WorldWideScience

Sample records for strain increases protease-activated

  1. Antioxidant and Anti-Protease Activities of Diazepinomicin from the Sponge-Associated Micromonospora Strain RV115

    OpenAIRE

    Abdelmohsen, Usama Ramadan; Szesny, Matthias; Othman, Eman Maher; Schirmeister, Tanja; Grond, Stephanie; Stopper, Helga; Hentschel, Ute

    2012-01-01

    Diazepinomicin is a dibenzodiazepine alkaloid with an unusual structure among the known microbial metabolites discovered so far. Diazepinomicin was isolated from the marine sponge-associated strain Micromonospora sp. RV115 and was identified by spectroscopic analysis and by comparison to literature data. In addition to its interesting preclinical broad-spectrum antitumor potential, we report here new antioxidant and anti-protease activities for this compound. Using the ferric reducing antioxi...

  2. Inhibition of sulfur mustard-increased protease activity by niacinamide, N-acetyl-L-cysteine or dexamethasone

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, F.M.; Broomfield, C.A.; Smith, W.J.

    1991-03-11

    The pathologic mechanism of sulfur mustard-induced skin vesication is as yet undefined. Papirmeister et al. have postulated a biochemical mechanism for sulfur mustard-induced cutaneous injury involving sequelae of DNA alkylation, metabolic disruption resulting in NAD+ depletion and activation of protease. The authors have utilized a chromogenic peptide substrate assay to establish that human peripheral blood lymphocytes exposed 24 hr previously to sulfur mustard exhibited an increase in proteolytic activity. Doses of compounds known to alter the biochemical events associated with sulfur mustard exposure or reduce protease activity were tested in this system for their ability to block the sulfur mustard-induced protease activity. Treatment with niacinamide 1 hr after or with N-acetyl-L-cysteine or dexamethasone 24 hr prior to sulfur mustard exposure resulted in a decrease of 39%, 33% and 42% respectively of sulfur mustard-increased protease activity. These data suggest that therapeutic intervention into the biochemical pathways that culminate in protease activation might serve as an approach to treatment of sulfur mustard-induced pathology.

  3. Antioxidant and anti-protease activities of diazepinomicin from the sponge-associated Micromonospora strain RV115.

    Science.gov (United States)

    Abdelmohsen, Usama Ramadan; Szesny, Matthias; Othman, Eman Maher; Schirmeister, Tanja; Grond, Stephanie; Stopper, Helga; Hentschel, Ute

    2012-10-01

    Diazepinomicin is a dibenzodiazepine alkaloid with an unusual structure among the known microbial metabolites discovered so far. Diazepinomicin was isolated from the marine sponge-associated strain Micromonospora sp. RV115 and was identified by spectroscopic analysis and by comparison to literature data. In addition to its interesting preclinical broad-spectrum antitumor potential, we report here new antioxidant and anti-protease activities for this compound. Using the ferric reducing antioxidant power (FRAP) assay, a strong antioxidant potential of diazepinomicin was demonstrated. Moreover, diazepinomicin showed a significant antioxidant and protective capacity from genomic damage induced by the reactive oxygen species hydrogen peroxide in human kidney (HK-2) and human promyelocytic (HL-60) cell lines. Additionally, diazepinomicin inhibited the proteases rhodesain and cathepsin L at an IC₅₀ of 70-90 µM. It also showed antiparasitic activity against trypomastigote forms of Trypanosoma brucei with an IC₅₀ of 13.5 µM. These results showed unprecedented antioxidant and anti-protease activities of diazepinomicin, thus further highlighting its potential as a future drug candidate.

  4. Antioxidant and Anti-Protease Activities of Diazepinomicin from the Sponge-Associated Micromonospora Strain RV115

    Directory of Open Access Journals (Sweden)

    Helga Stopper

    2012-10-01

    Full Text Available Diazepinomicin is a dibenzodiazepine alkaloid with an unusual structure among the known microbial metabolites discovered so far. Diazepinomicin was isolated from the marine sponge-associated strain Micromonospora sp. RV115 and was identified by spectroscopic analysis and by comparison to literature data. In addition to its interesting preclinical broad-spectrum antitumor potential, we report here new antioxidant and anti-protease activities for this compound. Using the ferric reducing antioxidant power (FRAP assay, a strong antioxidant potential of diazepinomicin was demonstrated. Moreover, diazepinomicin showed a significant antioxidant and protective capacity from genomic damage induced by the reactive oxygen species hydrogen peroxide in human kidney (HK-2 and human promyelocytic (HL-60 cell lines. Additionally, diazepinomicin inhibited the proteases rhodesain and cathepsin L at an IC50 of 70–90 µM. It also showed antiparasitic activity against trypomastigote forms of Trypanosoma brucei with an IC50 of 13.5 µM. These results showed unprecedented antioxidant and anti-protease activities of diazepinomicin, thus further highlighting its potential as a future drug candidate.

  5. Increased expression of cathelicidin by direct activation of protease-activated receptor 2: possible implications on the pathogenesis of rosacea.

    Science.gov (United States)

    Kim, Ji Young; Kim, Yoon Jee; Lim, Beom Jin; Sohn, Hyo Jung; Shin, Dongyun; Oh, Sang Ho

    2014-11-01

    Recent findings of increased cathelicidin protein and its proteolytic fragments in rosacea suggest a pathogenic role for cathelicidin in this disease. The relationship between cathelicidin and protease-activated receptor 2 (PAR-2) is therefore of interest, as PAR-2, expressed principally in keratinocytes, regulates pro-inflammatory cytokine expression in the skin. The purpose of this study was to determine the relationship between expression of PAR-2 and cathelicidin in rosacea and to test the effect of direct PAR-2 activation on cathelicidin expression in keratinocytes. Samples from 40 patients with clinicopathologic diagnosis of rosacea and facial skin tissue samples from 20 patients with no specific findings or milium without inflammation were retrieved. Intensities of immunohistochemical staining for PAR-2 and cathelicidin were compared between normal and rosacea-affected skin tissues. Additionally, correlations between PAR-2 and cathelicidin staining intensities within rosacea patients were analyzed. In cultured keratinocytes, changes in PAR-2, cathelicidin, and vascular endothelial growth factor (VEGF) mRNA and protein were analyzed after treatment with PAR-2 activating peptide (AP). Cathelicidin expression was significantly higher in rosacea skin tissues than in normal tissues (prosacea tissues than in normal skin tissues. A positive correlation between PAR-2 and cathelicidin within rosacea samples was observed (R=0.330, p=0.037). After treatment of PAR-2 AP, both mRNA and protein levels for PAR-2, cathelicidin, and VEGF significantly increased in cultured keratinocytes, compared with PAR-2 control peptide treatment. PAR-2 may participate in the pathogenesis of rosacea through activation of cathelicidin LL-37, a mediator of innate immune responses in the skin.

  6. Zebra chip disease decreases tuber (Solanum tuberosum L.) protein content by attenuating protease inhibitor levels and increasing protease activities.

    Science.gov (United States)

    Kumar, G N Mohan; Knowles, Lisa O; Knowles, N Richard

    2015-11-01

    Zebra chip disease of potato decreases protease inhibitor levels resulting in enhanced serine-type protease activity, decreased protein content and altered protein profiles of fully mature tubers. Zebra-chip (ZC), caused by Candidatus Liberibacter solanacearum (CLso), is a relatively new disease of potato that negatively affects growth, yield, propagation potential, and fresh and process qualities of tubers. Diseased plants produce tubers with characteristic brown discoloration of vascular tissue accompanied by elevated levels of free amino acids and reducing sugars. Here we demonstrate that ZC disease induces selective protein catabolism in tubers through modulating protease inhibitor levels. Soluble protein content of tubers from CLso-infected plants was 33% lower than from non-infected plants and electrophoretic analyses revealed substantial reductions in major tuber proteins. Patatin (~40 kDa) and ser-, asp- (22 kDa) and cys-type (85 kDa) protease inhibitors were either absent or greatly reduced in ZC-afflicted tubers. In contrast to healthy (non-infected) tubers, the proteolytic activity in CLso infected tubers was high and the ability of extracts from infected tubers to inhibit trypsin (ser-type) and papain (cys-type) proteases greatly attenuated. Moreover, extracts from CLso-infected tubers rapidly catabolized proteins purified from healthy tubers (40 kDa patatin, 22 kDa protease inhibitors, 85 kDa potato multicystatin) when subjected to proteolysis individually. In contrast, crude extracts from non-infected tubers effectively inhibited the proteolytic activity from ZC-afflicted tubers. These results suggest that the altered protein profile of ZC afflicted tubers is largely due to loss of ser- and cys-type protease inhibitors. Further analysis revealed a novel PMSF-sensitive (ser) protease (ca. 80-120 kDa) in CLso infected tubers. PMSF abolished the proteolytic activities responsible for degrading patatin, the 22 kDa protease inhibitor(s) and potato

  7. Immunoglobulin A1 protease activity in Gemella haemolysans

    DEFF Research Database (Denmark)

    Lomholt, JA; Kilian, Mogens

    2000-01-01

    The purpose of this study was to determine the occurrence and nature of immunoglobulin A1 (IgA1) protease activity in members of the genus Gemella and related taxa. Among a total of 22 Gemella strains belonging to the four species Gemella haemolysans, Gemella morbillorum, Gemella sanguinis...

  8. Changes in protease activity and Cry3Aa toxin binding in the Colorado potato beetle: implications for insect resistance to Bacillus thuringiensis toxins

    Science.gov (United States)

    Olga Loseva; Mohamed Ibrahim; Mehmet Candas; C. Noah Koller; Leah S. Bauer; Lee A. Jr. Bulla

    2002-01-01

    Widespread commercial use of Bacillus thuringiensis Cry toxins to control pest insects has increased the likelihood for development of insect resistance to this entomopathogen. In this study, we investigated protease activity profiles and toxin-binding capacities in the midgut of a strain of Colorado potato beetle (CPB) that has developed resistance...

  9. Time-Dependent Increases in Protease Activities for Neuronal Apoptosis in Spinal Cords of Lewis Rats During Development of Acute Experimental Autoimmune Encephalomyelitis

    Science.gov (United States)

    Das, Arabinda; Guyton, M. Kelly; Matzelle, Denise D.; Ray, Swapan K.; Banik, Naren L.

    2008-01-01

    Multiple sclerosis (MS) is characterized by axonal demyelination and neurodegeneration, the latter having been inadequately explored in the MS animal model experimental autoimmune encephalomyelitis (EAE). The purpose of this study was to examine the time-dependent correlation between increased calpain and caspase activities and neurodegeneration in spinal cord tissues from Lewis rats with acute EAE. An increase in TUNEL-positive neurons and internucleosomal DNA fragmentation in EAE spinal cords suggested that neuronal death was a result of apoptosis on days 8–10 following induction of EAE. Increases in calpain expression in EAE correlated with activation of pro-apoptotic proteases, leading to apoptotic cell death beginning on day 8 of EAE, which occurred before the appearance of visible clinical symptoms. Increases in calcineurin expression and decreases in phospho-Bad (p-Bad) suggested Bad activation in apoptosis during acute EAE. Increases in the Bax:Bcl-2 ratio and activation of caspase-9 showed the involvement of mitochondria in apoptosis. Further, caspase-8 activation suggested induction of the death receptor–mediated pathway for apoptosis. Endoplasmic reticulum stress leading to caspase-3 activation was also observed, indicating that multiple apoptotic pathways were activated following EAE induction. In contrast, cell death was mostly a result of necrosis on the later day (day 11), when EAE entered a severe stage. From these findings, we conclude that increases in calpain and caspase activities play crucial roles in neuronal apoptosis during the development of acute EAE. PMID:18521931

  10. Protease activity of legumain is inhibited by an increase of cystatin E/M in the DJ-1-knockout mouse spleen, cerebrum and heart

    Directory of Open Access Journals (Sweden)

    Takuya Yamane

    2017-03-01

    Full Text Available Legumain (EC 3.4.22.34 is an asparaginyl endopeptidase. Legumain activity has been detected in various mouse tissues including the kidney, spleen and epididymis. Legumain is overexpressed in the majority of human solid tumors and transcription of the legumain gene is regulated by the p53 tumor suppressor in HCT116 cells. The legumain activity is also increased under acid conditions in Alzheimer's disease brains. DJ-1/PARK7, a cancer- and Parkinson's disease-associated protein, works as a coactivator to various transcription factors, including the androgen receptor, p53, PSF, Nrf2, SREBP and RREB1. Recently, we found that legumain expression, activation and cleavage of annexin A2 are regulated by DJ-1 through p53. In this study, we found that the expression levels of legumain mRNA were increased in the cerebrum, kidney, spleen, heart, lung, epididymis, stomach, small intestine and pancreas from DJ-1-knockout mice, although legumain activity levels were decreased in the cerebrum, spleen and heart from DJ-1-knockout mice. Furthermore, we found that cystatin E/M expression was increased in the spleen, cerebrum and heart from DJ-1-knockout mice. These results suggest that reduction of legumain activity is caused by an increase of cystatin E/M expression in the spleen, cerebrum and heart from DJ-1-knockout mice.

  11. Esterase and protease activities of Bacillus spp. from afitin, iru and ...

    African Journals Online (AJOL)

    The electrophoretic profiles of fermented African locust bean protein (ALBP), using strains presenting the highest protease activities in casein agar, were analyzed by SDS-PAGE to select strains with good ability to be used as starter cultures. All the Bacillus spp. tested showed esterase activity against tributyrin with high ...

  12. Protease-activated receptor 2, a receptor involved in melanosome transfer, is upregulated in human skin by ultraviolet irradiation.

    Science.gov (United States)

    Scott, G; Deng, A; Rodriguez-Burford, C; Seiberg, M; Han, R; Babiarz, L; Grizzle, W; Bell, W; Pentland, A

    2001-12-01

    Previous studies have shown that the protease-activated receptor 2 is involved in skin pigmentation through increased phagocytosis of melanosomes by keratinocytes. Ultraviolet irradiation is a potent stimulus for melanosome transfer. We show that protease-activated receptor 2 expression in human skin is upregulated by ultraviolet irradiation. Subjects with skin type I, II, or III were exposed to two or three minimal erythema doses of irradiation from a solar simulator. Biopsies were taken from nonexposed and irradiated skin 24 and 96 h after irradiation and protease-activated receptor 2 expression was detected using immunohistochemical staining. In nonirradiated skin, protease-activated receptor 2 expression was confined to keratinocytes in the lower one-third of the epidermis. After ultraviolet irradiation protease-activated receptor 2 expression was observed in keratinocytes in the upper two-thirds of the epidermis or the entire epidermis at both time points studied. Subjects with skin type I showed delayed upregulation of protease-activated receptor 2 expression, however, compared with subjects with skin types II and III. Irradiated cultured human keratinocytes showed upregulation in protease-activated receptor 2 expression as determined by immunofluorescence microscopy and Western blotting. Cell culture supernatants from irradiated keratinocytes also exhibited a dose-dependent increase in protease-activated receptor-2 cleavage activity. These results suggest an important role for protease-activated receptor-2 in pigmentation in vivo. Differences in protease-activated receptor 2 regulation in type I skin compared with skin types II and III suggest a potential mechanism for differences in tanning in subjects with different skin types.

  13. A preliminary study of the protease activities in germinating brown rice (Oryza sativa L.).

    Science.gov (United States)

    Li, Cuijuan; Cao, Xiaohong; Gu, Zhenxin; Wen, Huanbin

    2011-03-30

    Proteases hydrolyse storage proteins to provide precursors for perpetuating species. The aim of this study was to investigate and characterise different proteases in germinating brown rice. The protease activity of brown rice increased sevenfold during 7 days of germination. It was highest on day 6 when determined at pH 3.5. With casein as substrate the proteases showed two catalytic groups: acidic proteases with an optimal pH of 3.5 and alkaline proteases with an optimal pH of 8.0. The acidic protease activity was inhibited by Ba(2+) and Pb(2+) but stimulated by Zn(2+) , while the alkaline protease activity was inhibited by Ca(2+) and Pb(2+) but stimulated by Mg(2+) and Zn(2+) . SDS-gelatin-PAGE assay showed two protease activity bands at pH 3.5, while two different bands with higher molecular weights were observed at pH 8.0. Inhibition assay revealed that pepstatin A and E-64 inhibited 67.63 and 38.26% respectively of the protease activity at pH 3.5, indicating the presence of aspartic and cysteine proteases. Metalloproteases played a major role under alkaline conditions (88.37% inhibition with EDTA). Germinated brown rice proteases fall into different classes with different properties. This study is helpful for their further purification. Copyright © 2010 Society of Chemical Industry.

  14. Pharmacological Targeting of Protease-Activated Receptor 2 Affords Protection from Bleomycin-Induced Pulmonary Fibrosis

    NARCIS (Netherlands)

    Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C. Arnold

    2015-01-01

    Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease that remains refractory to therapy. Despite increasing evidence that protease-activated receptor 2 (PAR-2) contributes to fibrosis, its importance in pulmonary fibrosis is under debate. We addressed whether PAR-2

  15. Pharmacological targeting of protease-activated receptor 2 affords protection from bleomycin-induced pulmonary fibrosis

    NARCIS (Netherlands)

    C. Lin (Cong); J. von der Thusen (Jan); J. Daalhuisen (Joost); M. Ten Brink (Marieke); B. Crestani (Bruno); T. van der Poll (Tom); K. Borensztajn (Keren); C. Arnold Spek (C.)

    2015-01-01

    textabstractIdiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease that remains refractory to therapy. Despite increasing evidence that protease-activated receptor 2 (PAR-2) contributes to fibrosis, its importance in pulmonary fibrosis is under debate. We addressed

  16. Acanthamoeba protease activity promotes allergic airway inflammation via protease-activated receptor 2.

    Directory of Open Access Journals (Sweden)

    Mi Kyung Park

    Full Text Available Acanthamoeba is a free-living amoeba commonly present in the environment and often found in human airway cavities. Acanthamoeba possesses strong proteases that can elicit allergic airway inflammation. To our knowledge, the aeroallergenicity of Acanthamoeba has not been reported. We repeatedly inoculated mice with Acanthamoeba trophozoites or excretory-secretory (ES proteins intra-nasally and evaluated symptoms and airway immune responses. Acanthamoeba trophozoites or ES proteins elicited immune responses in mice that resembled allergic airway inflammation. ES proteins had strong protease activity and activated the expression of several chemokine genes (CCL11, CCL17, CCL22, TSLP, and IL-25 in mouse lung epithelial cells. The serine protease inhibitor phenyl-methane-sulfonyl fluoride (PMSF inhibited ES protein activity. ES proteins also stimulated dendritic cells and enhanced the differentiation of naive T cells into IL-4-secreting T cells. After repeated inoculation of the protease-activated receptor 2 knockout mouse with ES proteins, airway inflammation and Th2 immune responses were markedly reduced, but not to basal levels. Furthermore, asthma patients had higher Acanthamoeba-specific IgE titers than healthy controls and we found Acanthamoeba specific antigen from house dust in typical living room. Our findings suggest that Acanthamoeba elicits allergic airway symptoms in mice via a protease allergen. In addition, it is possible that Acanthamoeba may be one of the triggers human airway allergic disease.

  17. Acanthamoeba Protease Activity Promotes Allergic Airway Inflammation via Protease-Activated Receptor 2

    Science.gov (United States)

    Park, Mi Kyung; Cho, Min Kyoung; Kang, Shin Ae; Park, Hye-Kyung; Kim, Dong-Hee; Yu, Hak Sun

    2014-01-01

    Acanthamoeba is a free-living amoeba commonly present in the environment and often found in human airway cavities. Acanthamoeba possesses strong proteases that can elicit allergic airway inflammation. To our knowledge, the aeroallergenicity of Acanthamoeba has not been reported. We repeatedly inoculated mice with Acanthamoeba trophozoites or excretory-secretory (ES) proteins intra-nasally and evaluated symptoms and airway immune responses. Acanthamoeba trophozoites or ES proteins elicited immune responses in mice that resembled allergic airway inflammation. ES proteins had strong protease activity and activated the expression of several chemokine genes (CCL11, CCL17, CCL22, TSLP, and IL-25) in mouse lung epithelial cells. The serine protease inhibitor phenyl-methane-sulfonyl fluoride (PMSF) inhibited ES protein activity. ES proteins also stimulated dendritic cells and enhanced the differentiation of naive T cells into IL-4-secreting T cells. After repeated inoculation of the protease-activated receptor 2 knockout mouse with ES proteins, airway inflammation and Th2 immune responses were markedly reduced, but not to basal levels. Furthermore, asthma patients had higher Acanthamoeba-specific IgE titers than healthy controls and we found Acanthamoeba specific antigen from house dust in typical living room. Our findings suggest that Acanthamoeba elicits allergic airway symptoms in mice via a protease allergen. In addition, it is possible that Acanthamoeba may be one of the triggers human airway allergic disease. PMID:24658532

  18. Synergism of Selective Tumor Vascular Thrombosis and Protease Activated Prodrug

    National Research Council Canada - National Science Library

    Liu, Cheng

    2008-01-01

    ... by administration of protease-activated prodrug. The activation of coagulation cascade and tumor vascular thrombosis as well as the following activation of the thrombolytic pathways led to explosive amplification of serine protease cascades...

  19. Allergens with Protease Activity from House Dust Mites

    Directory of Open Access Journals (Sweden)

    Manuel Reithofer

    2017-06-01

    Full Text Available Globally, house dust mites (HDM are one of the main sources of allergens causing Type I allergy, which has a high risk of progressing into a severe disabling disease manifestation such as allergic asthma. The strong protease activities of a number of these allergens are thought to be involved in several steps of the pathophysiology of this allergic disease. It has been a common notion that protease activity may be one of the properties that confers allergenicity to proteins. In this review we summarize and discuss the roles of the different HDM proteases in the development of Type I allergy.

  20. Comparative characterization of protease activity in cultured spotted rose snapper juveniles (Lutjanus guttatus

    Directory of Open Access Journals (Sweden)

    Emyr Peña

    2015-09-01

    Full Text Available Partial characterizations of digestive proteases were studied in three life stages of spotted rose snapper: early (EJ, middle (MJ and late juvenile (LJ with corresponding average weights of 21.3 ± 2.6 g (3 months after hatching, MAH, 190 ± 4.4 g (7 MAH, and 400 ± 11.5 g (12 MAH. At sampling points, the digestive tract was dissected into the stomach (St, pyloric caeca (PC, and the intestine in three sections (proximal (PI, middle (MI and distal intestine (DI. The effect of pH and temperature and specific inhibitors were evaluated for acid and alkaline proteases. Total acid and alkaline protease activity showed a tendency to increase with juvenile life stage of fish while trypsin activity decreased. Differences were found in acid and alkaline protease activities at different pH and temperatures during juvenile stages. Pepstatin A inhibited total activity in the stomach extract in all juvenile stages. Activity in total alkaline protease inhibition was significantly higher in EJ using TLCK, PMSF, SBTI, Phen and Ovo than in MJ and LJ, while no significant differences were found with TPCK inhibition. Therefore increases in protease activities with fish growth through juvenile stages in which a substitution or diversification in the type of alkaline enzymes exist. These results lead a better comprehension of changes in digestive potential of Lutjanidae fish.

  1. Increasing the alkaline protease activity of Bacillus cereus and ...

    African Journals Online (AJOL)

    User

    2011-05-09

    73441, Iran. Accepted 1 April, 2011 ... Bacterial spores are amongst the most resistant of all microbial forms to inactivation by chemical or ... containing soya flour, starch and wheat bran as the main com-ponents. The produced ...

  2. Skeletal muscle protease activities in the early growth and development of wild Atlantic salmon (Salmo salar L.).

    Science.gov (United States)

    Lysenko, Liudmila A; Kantserova, Nadezda P; Kaivarainen, Elena I; Krupnova, Marina Yu; Nemova, Nina N

    2017-09-01

    Growth-related dynamics of intracellular protease activities in four year classes of the Atlantic salmon (Salmo salar L. 1758) parr and smolts inhabiting salmon rivers of northwestern Russia (the White Sea basin) were studied. Cathepsin B, cathepsin D, proteasome, and calpain activities in the skeletal muscles of salmon were assessed to investigate their relative contribution to the total protein degradation as well as to young fish growth process. It was confirmed that calpain activity dominates in salmon muscles while proteasome plays a minor role, in contrast to terrestrial vertebrates. Calpain and proteasome activities were maximal at the early post-larval stage (in parrs 0+) and declined with age (parrs 1+ through 2+) dropping to the lowest level in salmon smolts. Annual growth increments and proteolytic activities of calpains and proteasome in the muscles of salmon juveniles changed with age in an orchestrated manner, while lysosomal cathepsin activities increased with age. Comparing protease activities and growth increments in salmon parr and smolts we suggested that the partial suppression of the protein degradation could be a mechanism stimulating efficient growth in smoltifying salmon. Growth and smoltification-related dynamics of protease activities was quite similar in salmon populations from studied spawning rivers, such as Varzuga and Indera; however, some habitat-related differences were observed. Growth increments and protease activities varied in salmon parr 0+ (but not on later ages) inhabiting either main rivers or small tributaries apparently due to habitat difference on the resources for fish growth. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Protease activated receptors (PARS) mediation in gyroxin biological activity

    International Nuclear Information System (INIS)

    Silva, Jose Alberto Alves da

    2009-01-01

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH 2 , respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  4. Protease activated receptor-2 (PAR2): possible target of phytochemicals.

    Science.gov (United States)

    Kakarala, Kavita Kumari; Jamil, Kaiser

    2015-09-01

    The use of phytochemicals either singly or in combination with other anticancer drugs comes with an advantage of less toxicity and minimal side effects. Signaling pathways play central role in cell cycle, cell growth, metabolism, etc. Thus, the identification of phytochemicals with promising antagonistic effect on the receptor/s playing key role in single transduction may have better therapeutic application. With this background, phytochemicals were screened against protease-activated receptor 2 (PAR2). PAR2 belongs to the superfamily of GPCRs and is an important target for breast cancer. Using in silico methods, this study was able to identify the phytochemicals with promising binding affinity suggesting their therapeutic potential in the treatment of breast cancer. The findings from this study acquires importance as the information on the possible agonists and antagonists of PAR2 is limited due its unique mechanism of activation.

  5. Rapid Detection of Thrombin and Other Protease Activity Directly in Whole Blood

    Science.gov (United States)

    Yu, Johnson Chung Sing

    Thrombin is a serine protease that plays a key role in the clotting cascade to promote hemostasis following injury to the endothelium. From a clinical diagnostic perspective, in-vivo thrombin activity is linked to various blood clotting disorders, as well as cardiovascular disease (DVT, arteriosclerosis, etc). Thus, the ability to rapidly measure protease activity directly in whole blood will provide important new diagnostics, and clinical researchers with a powerful tool to further elucidate the relationship between circulating protease levels and disease. The ultimate goal is to design novel point of care (POC) diagnostic devices that are capable of monitoring protease activities directly in whole blood and biological sample. A charge-changing substrate specific to the thrombin enzyme was engineered and its functionality was confirmed by a series of experiments. This led to the preliminary design, construction, and testing of two device platforms deemed fully functional for the electrophoretic separation and focusing of charged peptide fragments. The concept of using the existing charge-changing substrate platform for bacterial protease detection was also investigated. Certain strains of E coli are associated with severe symptoms such as abdominal cramps, bloody diarrhea, and vomiting. The OmpT protease is expressed on the outer membrane of E coli and plays a role in the cleavage of antimicrobial peptides, the degradation of recombinant heterologous proteins, and the activation of plasminogen in the host. Thus, a synthetic peptide substrate specific to the OmpT protease was designed and modeled for the purpose of detecting E coli in biological sample.

  6. Protease-activated receptors in kidney disease progression.

    Science.gov (United States)

    Palygin, Oleg; Ilatovskaya, Daria V; Staruschenko, Alexander

    2016-12-01

    Protease-activated receptors (PARs) are members of a well-known family of transmembrane G protein-coupled receptors (GPCRs). Four PARs have been identified to date, of which PAR1 and PAR2 are the most abundant receptors, and have been shown to be expressed in the kidney vascular and tubular cells. PAR signaling is mediated by an N-terminus tethered ligand that can be unmasked by serine protease cleavage. The receptors are activated by endogenous serine proteases, such as thrombin (acts on PARs 1, 3, and 4) and trypsin (PAR2). PARs can be involved in glomerular, microvascular, and inflammatory regulation of renal function in both normal and pathological conditions. As an example, it was shown that human glomerular epithelial and mesangial cells express PARs, and these receptors are involved in the pathogenesis of crescentic glomerulonephritis, glomerular fibrin deposition, and macrophage infiltration. Activation of these receptors in the kidney also modulates renal hemodynamics and glomerular filtration rate. Clinical studies further demonstrated that the concentration of urinary thrombin is associated with glomerulonephritis and type 2 diabetic nephropathy; thus, molecular and functional mechanisms of PARs activation can be directly involved in renal disease progression. We briefly discuss here the recent literature related to activation of PAR signaling in glomeruli and the kidney in general and provide some examples of PAR1 signaling in glomeruli podocytes. Copyright © 2016 the American Physiological Society.

  7. Pathogen-secreted proteases activate a novel plant immune pathway.

    Science.gov (United States)

    Cheng, Zhenyu; Li, Jian-Feng; Niu, Yajie; Zhang, Xue-Cheng; Woody, Owen Z; Xiong, Yan; Djonović, Slavica; Millet, Yves; Bush, Jenifer; McConkey, Brendan J; Sheen, Jen; Ausubel, Frederick M

    2015-05-14

    Mitogen-activated protein kinase (MAPK) cascades play central roles in innate immune signalling networks in plants and animals. In plants, however, the molecular mechanisms of how signal perception is transduced to MAPK activation remain elusive. Here we report that pathogen-secreted proteases activate a previously unknown signalling pathway in Arabidopsis thaliana involving the Gα, Gβ, and Gγ subunits of heterotrimeric G-protein complexes, which function upstream of an MAPK cascade. In this pathway, receptor for activated C kinase 1 (RACK1) functions as a novel scaffold that binds to the Gβ subunit as well as to all three tiers of the MAPK cascade, thereby linking upstream G-protein signalling to downstream activation of an MAPK cascade. The protease-G-protein-RACK1-MAPK cascade modules identified in these studies are distinct from previously described plant immune signalling pathways such as that elicited by bacterial flagellin, in which G proteins function downstream of or in parallel to an MAPK cascade without the involvement of the RACK1 scaffolding protein. The discovery of the new protease-mediated immune signalling pathway described here was facilitated by the use of the broad host range, opportunistic bacterial pathogen Pseudomonas aeruginosa. The ability of P. aeruginosa to infect both plants and animals makes it an excellent model to identify novel immunoregulatory strategies that account for its niche adaptation to diverse host tissues and immune systems.

  8. Detection of protease activity by fluorescent protein FRET sensors: from computer simulation to live cells

    Science.gov (United States)

    Goryashchenko, Alexander S.; Khrenova, Maria G.; Savitsky, Alexander P.

    2018-04-01

    Förster resonance energy transfer (FRET) sensors are widely used for the detection of protease activity in vitro and in vivo. Usually they consist of a FRET pair connected with a polypeptide linker containing a specific cleavage site for the relevant protease. Use of the fluorescent proteins as components of the FRET pair allows genetic encoding of such sensors and solves the problem of their delivery into live cells and animals. There are several ways to improve the properties of such sensors, mainly to increase FRET efficiency and therefore the dynamic range. One of the ways to achieve this is to use a non-fluorescent chromoprotein as an acceptor. Molecular dynamic simulations may assist in the construction of linker structures connecting donor and acceptor molecules. Estimation of the orientation factor κ 2 can be obtained by methods based on quantum theory and combined quantum mechanics/molecular mechanics approaches. The linker can be structured by hydrophobic interactions, bringing it into a closed conformation that shortens the distance between donor and acceptor and, consequently, increases FRET efficiency. We analyzed the effects of different linker structures on the detection of caspase-3 activity using a non-fluorescent acceptor. Also we have constructed the Tb3+- TagRFP sensor in which a complex of the terbium ion and terbium-binding peptide is used as a donor. This allowed us to use the unique property of lanthanide ions—fluorescence lifetime up to milliseconds—to perform measurements with time delay and exclude the nanosecond-order fluorescence. Using our systems as a starting point, by changing the recognition site in the linker it is possible to perform imaging of different protease activity in vitro or in vivo.

  9. Survey of immunoglobulin A protease activity among selected species of Ureaplasma and Mycoplasma: specificity for host immunoglobulin A.

    Science.gov (United States)

    Kapatais-Zoumbos, K; Chandler, D K; Barile, M F

    1985-03-01

    Because immunoglobulin A (IgA) is the predominant immunoglobulin at mucosal surfaces, IgA proteases produced by pathogenic bacteria are considered potential virulence factors for organisms that cause disease or gain entry at mucous membranes. To determine the role of IgA protease in the pathogenicity of mycoplasmal disease, a variety of human and animal mycoplasma and ureaplasma species were examined for IgA protease activity with human, murine, porcine, and canine IgA. None of the mycoplasma species examined showed detectable IgA protease activity with any of the IgAs tested. Twenty-eight strains of Ureaplasma urealyticum isolated from human urogenital tissues cleaved human IgA1, but no cleavage of human IgA2 or murine, porcine, or canine IgA was observed. Ureaplasmas isolated from nonhuman hosts (feline, canine, avian, and bovine [Ureaplasma diversum]) did not cleave human IgA1. Two strains of canine ureaplasmas were able to cleave canine IgA, but not murine IgA. Thus, ureaplasmas from other species can produce IgA protease, but the specificity of the enzyme was restricted to the IgA of the appropriate host. This finding suggests that IgA proteases could play a role in the selective host specificity of mucosal pathogens.

  10. Isolation of Mucorales from processed maize (Zea mays L.) and screening for protease activity

    OpenAIRE

    de Azevedo Santiago, Andr? Luiz Cabral Monteiro; de Souza Motta, Cristina Maria

    2008-01-01

    Mucorales were isolated from maize flour, corn meal and cooked cornflakes using surface and depth plate methods. Rhizopus oryzae, Circinella muscae, Mucor subtilissimus, Mucor hiemalis f. hiemalis, Syncephalastrum racemosum, Rhizopus microsporus var. chinensis and Absidia cylindrospora showed protease activity.

  11. THE EFFECT OF FEEDING Lactobacillus ON GROWTH, SURVIVAL RATE AND PROTEASE ACTIVITY OF Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Nunak Nafiqoh

    2011-12-01

    Full Text Available This study examined the effect of two Lactobacillus bacteria on protease activity and growth rate of Litopenaeus vannamei. An experiment was conducted to examine protease activity and growth rate. The experiment consisted of two treatment tanks, the first tank was provided with artemia immersed in 2.6 x 1016 cfu/mL of bacteria solution, the second tank served as the control tank. After 20 days, the L. vannamei in the tank that received Lactobacillus have significantly different in growth, survival rate and protease activity (P<0.05 compared to the control, but no significant difference between Lactobacillus casei and Lactobacillus plantarum treatments. Within the digestive organ, protease activity of hepatopancreas and stomach demonstrated significant higher activity (P<0.05 compared to the intestine.

  12. Targeting protease activated receptor-1 with P1pal-12 limits bleomycin-induced pulmonary fibrosis

    NARCIS (Netherlands)

    Lin, Cong; Duitman, Janwillem; Daalhuisen, Joost; ten Brink, Marieke; von der Thüsen, Jan; van der Poll, Tom; Borensztajn, Keren; Spek, C. Arnold

    2014-01-01

    Idiopathic pulmonary fibrosis is the most devastating fibrotic diffuse parenchymal lung disease which remains refractory to pharmacological therapies. Therefore, novel treatments are urgently required. Protease-activated receptor (PAR)-1 is a G-protein-coupled receptor that mediates critical

  13. Reduction of protease activity in milk by continuous flow high-intensity pulsed electric field treatments.

    Science.gov (United States)

    Bendicho, S; Barbosa-Cánovas, G V; Martín, O

    2003-03-01

    High-intensity pulsed electric field (HIPEF) is a non-thermal food processing technology that is currently being investigated to inactivate microorganisms and certain enzymes, involving a limited increase of food temperature. Promising results have been obtained on the inactivation of microbial enzymes in milk when suspended in simulated milk ultrafiltrate. The aim of this study was to evaluate the effectiveness of continuous HIPEF equipment on inactivating a protease from Bacillus subtilis inoculated in milk. Samples were subjected to HIPEF treatments of up to 866 micros of squared wave pulses at field strengths from 19.7 to 35.5 kV/cm, using a treatment chamber that consisted of eight colinear chambers connected in series. Moreover, the effects of different parameters such as pulse width (4 and 7 micros), pulse repetition rates (67, 89, and 111 Hz), and milk composition (skim and whole milk) were tested. Protease activity decreased with increased treatment time or field strength and pulse repetition rate. Regarding pulse width, no differences were observed between 4 and 7 micros pulses when total treatment time was considered. On the other hand, it was observed that milk composition affected the results since higher inactivation levels were reached in skim than in whole milk. The maximum inactivation (81%) was attained in skim milk after an 866-micros treatment at 35.5 kV/cm and 111 Hz.

  14. MALT1 Protease Activity Is Required for Innate and Adaptive Immune Responses.

    Directory of Open Access Journals (Sweden)

    Jong W Yu

    Full Text Available CARMA-BCL10-MALT1 signalosomes play important roles in antigen receptor signaling and other pathways. Previous studies have suggested that as part of this complex, MALT1 functions as both a scaffolding protein to activate NF-κB through recruitment of ubiquitin ligases, and as a protease to cleave and inactivate downstream inhibitory signaling proteins. However, our understanding of the relative importance of these two distinct MALT1 activities has been hampered by a lack of selective MALT1 protease inhibitors with suitable pharmacologic properties. To fully investigate the role of MALT1 protease activity, we generated mice homozygous for a protease-dead mutation in MALT1. We found that some, but not all, MALT1 functions in immune cells were dependent upon its protease activity. Protease-dead mice had defects in the generation of splenic marginal zone and peritoneal B1 B cells. CD4+ and CD8+ T cells displayed decreased T cell receptor-stimulated proliferation and IL-2 production while B cell receptor-stimulated proliferation was partially dependent on protease activity. In dendritic cells, stimulation of cytokine production through the Dectin-1, Dectin-2, and Mincle C-type lectin receptors was also found to be partially dependent upon protease activity. In vivo, protease-dead mice had reduced basal immunoglobulin levels, and showed defective responses to immunization with T-dependent and T-independent antigens. Surprisingly, despite these decreased responses, MALT1 protease-dead mice, but not MALT1 null mice, developed mixed inflammatory cell infiltrates in multiple organs, suggesting MALT1 protease activity plays a role in immune homeostasis. These findings highlight the importance of MALT1 protease activity in multiple immune cell types, and in integrating immune responses in vivo.

  15. Protease-Activated Receptor-2 Is Associated with Terminal Differentiation of Epidermis and Eccrine Sweat Glands

    Science.gov (United States)

    Shin, Yong-Sup; Kim, Hyung Won; Kim, Chang Deok; Kim, Hyun-Woo; Park, Jin Woon; Jung, Sunggyun; Lee, Jeung-Hoon; Ko, Young-Kwon

    2015-01-01

    Background Protease-activated receptor 2 (PAR-2) participates in various biological activities, including the regulation of epidermal barrier homeostasis, inflammation, pain perception, and melanosome transfer in the skin. Objective To evaluate the basic physiological role of PAR-2 in skin. Methods We investigated PAR-2 expression in human epidermis, skin tumors, and cultured epidermal cells using western blot and immunohistochemical analysis. Additionally, we examined the effect of the PAR-2 agonist, SLIGRL-NH2, on cultured keratinocytes. Results Strong PAR-2 immunoreactivity was observed in the granular layer of normal human skin and the acrosyringium of the eccrine sweat glands. In contrast, weak PAR-2 immunoreactivity was seen in the granular layer of callused skin and in the duct and gland cells of the eccrine sweat glands. Interestingly, PAR-2 immunoreactivity was very weak or absent in the tumor cells of squamous cell carcinoma (SCC) and syringoma. PAR-2 was detected in primary keratinocytes and SV-40T-transformed human epidermal keratinocytes (SV-HEKs), an immortalized keratinocyte cell line, but not in SCC12 cells. SV-HEKs that were fully differentiated following calcium treatment displayed higher PAR-2 expression than undifferentiated SV-HEKs. Treatment of cultured SV-HEKs with PAR-2 agonist increased loricrin and filaggrin expression, a terminal differentiation marker. Conclusion Our data suggest that PAR-2 is associated with terminal differentiation of epidermis and eccrine sweat glands. PMID:26273149

  16. Pharmacological Targeting of Protease-Activated Receptor 2 Affords Protection from Bleomycin-Induced Pulmonary Fibrosis

    Science.gov (United States)

    Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C Arnold

    2015-01-01

    Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease that remains refractory to therapy. Despite increasing evidence that protease-activated receptor 2 (PAR-2) contributes to fibrosis, its importance in pulmonary fibrosis is under debate. We addressed whether PAR-2 deficiency persistently reduces bleomycin-induced pulmonary fibrosis or merely delays disease progression and whether pharmacological PAR-2 inhibition limits experimental pulmonary fibrosis. Bleomycin was instilled intranasally into wild-type or PAR-2–deficient mice in the presence/absence of a specific PAR-2 antagonist (P2pal-18S). Pulmonary fibrosis was consistently reduced in PAR-2–deficient mice throughout the fibrotic phase, as evident from reduced Ashcroft scores (29%) and hydroxyproline levels (26%) at d 28. Moreover, P2pal-18S inhibited PAR-2–induced profibrotic responses in both murine and primary human pulmonary fibroblasts (p bleomycin-treated wild-type mice but did not further reduce fibrosis in PAR-2–deficient mice. Importantly, P2pal-18S treatment starting even 7 d after the onset of fibrosis limits pulmonary fibrosis as effectively as when treatment was started together with bleomycin instillation. Overall, PAR-2 contributes to the progression of pulmonary fibrosis, and targeting PAR-2 may be a promising therapeutic strategy for treating pulmonary fibrosis. PMID:26147947

  17. A Novel Apoptotic Protease Activated in Human Breast Cancer Cells After Poisoning Topoisomerase I

    Science.gov (United States)

    1999-10-01

    the unknown protease activated by the active anti -breast cancer agent, B-lapachone (B- lap). The research team showed for the first time that B-lap...protease activated by the active anti -breast cancer agent, B-lapachone (B-lap). The research team showed for the first time that B-lap requires NQ01, a...leukemia cell line HL60 cells peroxide production in Trypanosoma cruzi . Acta Trop., 35: 35-40, 1978. undergoing apoptosis induced by DNA damage. Cancer

  18. Extracellular Protease Activity of Enteropathogenic Escherechia coli on Mucin Substrate

    Directory of Open Access Journals (Sweden)

    SRI BUDIARTI

    2007-03-01

    Full Text Available Enteropathogenic Escherichia coli (EPEC causes gastrointestinal infections in human. EPEC invasion was initiated by attachment and aggressive colonization on intestinal surface. Attachment of EPEC alter the intestine mucosal cells. Despite this, the pathogenic mechanism of EPEC infectior has not been fully understood. This research hypothesizes that extracellular proteolytic enzymes is necessary for EPEC colonization. The enzyme is secreted into gastrointestinal milieu and presumably destroy mucus layer cover the gastrointestinal tract. The objective of this study was to assay EPEC extracellular protease enzyme by using mucin substrate. The activity of EPEC extracellular proteolytic enzyme on 1% mucin substrate was investigated. Non-pathogenic E. coli was used as a negative control. Positive and tentative controls were Yersinia enterocolitica and Salmonella. Ten EPEC strains were assayed, seven of them were able to degrade mucin, and the highest activity was produced by K1.1 strain. Both positive and tentative controls also showed the ability to digest 0.20% mucin.

  19. Detection of extracellular protease activity in different species and genera of ectomycorrhizal fungi.

    Science.gov (United States)

    Nygren, Cajsa M R; Edqvist, Johan; Elfstrand, Malin; Heller, Gregory; Taylor, Andy F S

    2007-05-01

    In northern forest ecosystems, most soil nitrogen (N) is in organic form and forest trees are largely dependent on ectomycorrhizal (ECM) fungi and their degradative abilities for N uptake. The ability of ECM fungi to acquire N from organic substrates should, therefore, be a widespread trait given its ecological importance. However, little is known about the degradative abilities of most ECM fungi as they remain untested due to problems of isolation or extremely slow growth in pure culture. In this paper, we present data on extracellular protease activity of 32 species of ECM fungi, most of which have not previously been cultured. Milk powder plates and zymograms were compared for detecting protease activity in these intractable species. In total, 29/32 of the species produced extracellular protease activity, but detection was method dependent. Growth on milk powder plates detected protease activity in 28 of 32 species, while zymograms only detected proteases in Amanita muscaria, Russula chloroides, Lactarius deterrimus and Lactarius quieticolor. The study supports the hypothesis that protease excretion is a widespread physiological trait in ECM fungi and that this ability is of considerable significance for nitrogen uptake in forest ecosystems.

  20. Protease-activated receptor (PAR)-2 is required for PAR-1 signalling in pulmonary fibrosis

    NARCIS (Netherlands)

    Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C. Arnold

    2015-01-01

    Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease of unknown aetiology. Compelling evidence suggests that both protease-activated receptor (PAR)-1 and PAR-2 participate in the development of pulmonary fibrosis. Previous studies have shown that bleomycin-induced

  1. Protease-activated receptor-1 deficiency protects against streptozotocin-induced diabetic nephropathy in mice

    NARCIS (Netherlands)

    Waasdorp, Maaike; Duitman, Janwillem; Florquin, Sandrine; Spek, C. Arnold

    2016-01-01

    Endogenously administered activated protein C ameliorates diabetic nephropathy (DN) in a protease-activated receptor-1 (PAR-1)-dependent manner, suggesting that PAR-1 activation limits the progression of DN. Activation of PAR-1 in fibroblast-like cells, however, induces proliferation and

  2. Deletion of protease-activated receptor 2 prolongs survival of scrapie-inoculated mice

    Czech Academy of Sciences Publication Activity Database

    Matěj, R.; Olejár, Tomáš; Janoušková, O.; Holada, K.

    2012-01-01

    Roč. 93, č. 9 (2012), s. 2057-2061 ISSN 0022-1317 Institutional support: RVO:67985823 Keywords : protease-activated receptor (PAR2) * scrapie * neurodegenerative disorders Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 3.127, year: 2012

  3. Alternaria-derived serine protease activity drives IL-33–mediated asthma exacerbations

    Science.gov (United States)

    Snelgrove, Robert J.; Gregory, Lisa G.; Peiró, Teresa; Akthar, Samia; Campbell, Gaynor A.; Walker, Simone A.; Lloyd, Clare M.

    2014-01-01

    Background The fungal allergen Alternaria alternata is implicated in severe asthma and rapid onset life-threatening exacerbations of disease. However, the mechanisms that underlie this severe pathogenicity remain unclear. Objective We sought to investigate the mechanism whereby Alternaria was capable of initiating severe, rapid onset allergic inflammation. Methods IL-33 levels were quantified in wild-type and ST2−/− mice that lacked the IL-33 receptor given inhaled house dust mite, cat dander, or Alternaria, and the effect of inhibiting allergen-specific protease activities on IL-33 levels was assessed. An exacerbation model of allergic airway disease was established whereby mice were sensitized with house dust mite before subsequently being challenged with Alternaria (with or without serine protease activity), and inflammation, remodeling, and lung function assessed 24 hours later. Results Alternaria, but not other common aeroallergens, possessed intrinsic serine protease activity that elicited the rapid release of IL-33 into the airways of mice through a mechanism that was dependent upon the activation of protease activated receptor-2 and adenosine triphosphate signaling. The unique capacity of Alternaria to drive this early IL-33 release resulted in a greater pulmonary inflammation by 24 hours after challenge relative to the common aeroallergen house dust mite. Furthermore, this Alternaria serine protease–IL-33 axis triggered a rapid, augmented inflammation, mucus release, and loss of lung function in our exacerbation model. Conclusion Alternaria-specific serine protease activity causes rapid IL-33 release, which underlies the development of a robust TH2 inflammation and exacerbation of allergic airway disease. PMID:24636086

  4. Alternaria-derived serine protease activity drives IL-33-mediated asthma exacerbations.

    Science.gov (United States)

    Snelgrove, Robert J; Gregory, Lisa G; Peiró, Teresa; Akthar, Samia; Campbell, Gaynor A; Walker, Simone A; Lloyd, Clare M

    2014-09-01

    The fungal allergen Alternaria alternata is implicated in severe asthma and rapid onset life-threatening exacerbations of disease. However, the mechanisms that underlie this severe pathogenicity remain unclear. We sought to investigate the mechanism whereby Alternaria was capable of initiating severe, rapid onset allergic inflammation. IL-33 levels were quantified in wild-type and ST2(-/-) mice that lacked the IL-33 receptor given inhaled house dust mite, cat dander, or Alternaria, and the effect of inhibiting allergen-specific protease activities on IL-33 levels was assessed. An exacerbation model of allergic airway disease was established whereby mice were sensitized with house dust mite before subsequently being challenged with Alternaria (with or without serine protease activity), and inflammation, remodeling, and lung function assessed 24 hours later. Alternaria, but not other common aeroallergens, possessed intrinsic serine protease activity that elicited the rapid release of IL-33 into the airways of mice through a mechanism that was dependent upon the activation of protease activated receptor-2 and adenosine triphosphate signaling. The unique capacity of Alternaria to drive this early IL-33 release resulted in a greater pulmonary inflammation by 24 hours after challenge relative to the common aeroallergen house dust mite. Furthermore, this Alternaria serine protease-IL-33 axis triggered a rapid, augmented inflammation, mucus release, and loss of lung function in our exacerbation model. Alternaria-specific serine protease activity causes rapid IL-33 release, which underlies the development of a robust TH2 inflammation and exacerbation of allergic airway disease. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Apixaban Enhances Vasodilatation Mediated by Protease-Activated Receptor 2 in Isolated Rat Arteries

    Directory of Open Access Journals (Sweden)

    Ambra Villari

    2017-07-01

    Full Text Available Apixaban (APX is a direct inhibitor of factor X (FXa approved for prophylaxis and treatment of deep venous thrombosis and atrial fibrillation. Because FXa activates protease-activated receptor 2 (PAR-2 in endothelium and vascular smooth muscle, inhibition of FXa by APX may affect vasomotor function. The effect of APX was assessed in vitro, by wire myography, in rat mesenteric resistance arteries (MRAs and basilar arteries challenged with vasoconstrictors [phenylephrine (PE; 5-hydroxytryptamine (5-HT], vasodilators [acetylcholine (ACh; sodium nitroprusside (SNP] or with the PAR-2 peptide agonist SLIGRL. APX (10 μM reduced the vasoconstriction to PE and 5-HT while did not change the vasodilatation to ACh or SNP. SLIGRL induced concentration-dependent vasodilation in pre-constricted arteries, that was reduced by incubation with the NO inhibitor NG-nitro-L-arginine (L-NNA and abolished by endothelium removal. APX enhanced vasodilation to SLIGRL either in the presence or in the absence of L-NNA, but was ineffective in endothelium-denuded vessels. In preparations from heparin-treated rats (to inhibit FXa APX did not change the vasodilation to SLIGRL. FXa enzymatic activity, detected in mesentery homogenates from controls, was inhibited by APX, whereas APX-sensitive enzymatic activity was undetectable in homogenates from heparin-treated rats. Immunoblot analysis showed that incubation of MRA or aorta with APX increased the abundance of PAR-2, an effect not seen in MRA from heparin-treated rats or in endothelium-denuded aortas. In conclusion, inhibition of FXa by APX increases vasodilatation mediated by PAR-2. APX may act by inhibiting PAR-2 desensitization induced by endogenous FXa. This effect could be useful in the context of endothelial dysfunction associated to cardiovascular diseases.

  6. A protease-activated receptor-1 antagonist protects against podocyte injury in a mouse model of nephropathy

    Directory of Open Access Journals (Sweden)

    Yu Guan

    2017-10-01

    Full Text Available The kidney expresses protease-activated receptor-1 (PAR-1. PAR-1 is known as a thrombin receptor, but its role in kidney injury is not well understood. In this study, we examined the contribution of PAR-1 to kidney glomerular injury and the effects of its inhibition on development of nephropathy. Mice were divided into 3 groups: control, doxorubicin + vehicle (15 mg/kg doxorubicin and saline and doxorubicin + Q94 (doxorubicin at 15 mg/kg and the PAR-1 antagonist Q94 at 5 mg/kg/d groups. Where indicated, doxorubicin was administered intravenously and PAR-1 antagonist or saline vehicle by subcutaneous osmotic mini-pump. PAR-1 expression was increased in glomeruli of mice treated with doxorubicin. Q94 treatment significantly suppressed the increased albuminuria in these nephropathic mice. Pathological analysis showed that Q94 treatment significantly attenuated periodic acid–Schiff and desmin staining, indicators of podocyte injury, and also decreased glomerular levels of podocin and nephrin. Furthermore, thrombin increased intracellular calcium levels in podocytes. This increase was suppressed by Q94 and Rox4560, a transient receptor potential cation channel (TRPC3/6 antagonist. In addition, both Q94 and Rox4560 suppressed the doxorubicin-induced increase in activities of caspase-9 and caspase-3 in podocytes. These data suggested that PAR-1 contributes to development of podocyte and glomerular injury and that PAR-1 antagonists have therapeutic potential. Keywords: Protease-activated receptor-1, Podocyte, Transient receptor potential cation channel, Kidney injury

  7. Protease activated receptor signaling is required for African trypanosome traversal of human brain microvascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Dennis J Grab

    2009-07-01

    Full Text Available Using human brain microvascular endothelial cells (HBMECs as an in vitro model for how African trypanosomes cross the human blood-brain barrier (BBB we recently reported that the parasites cross the BBB by generating calcium activation signals in HBMECs through the activity of parasite cysteine proteases, particularly cathepsin L (brucipain. In the current study, we examined the possible role of a class of protease stimulated HBMEC G protein coupled receptors (GPCRs known as protease activated receptors (PARs that might be implicated in calcium signaling by African trypanosomes.Using RNA interference (RNAi we found that in vitro PAR-2 gene (F2RL1 expression in HBMEC monolayers could be reduced by over 95%. We also found that the ability of Trypanosoma brucei rhodesiense to cross F2RL1-silenced HBMEC monolayers was reduced (39%-49% and that HBMECs silenced for F2RL1 maintained control levels of barrier function in the presence of the parasite. Consistent with the role of PAR-2, we found that HBMEC barrier function was also maintained after blockade of Galpha(q with Pasteurella multocida toxin (PMT. PAR-2 signaling has been shown in other systems to have neuroinflammatory and neuroprotective roles and our data implicate a role for proteases (i.e. brucipain and PAR-2 in African trypanosome/HBMEC interactions. Using gene-profiling methods to interrogate candidate HBMEC pathways specifically triggered by brucipain, several pathways that potentially link some pathophysiologic processes associated with CNS HAT were identified.Together, the data support a role, in part, for GPCRs as molecular targets for parasite proteases that lead to the activation of Galpha(q-mediated calcium signaling. The consequence of these events is predicted to be increased permeability of the BBB to parasite transmigration and the initiation of neuroinflammation, events precursory to CNS disease.

  8. Differential Expression of Extracellular Lipase and Protease Activities of Mycelial and Yeast Forms in Malassezia furfur.

    Science.gov (United States)

    Juntachai, Weerapong; Kajiwara, Susumu

    2015-10-01

    Malassezia furfur is a dimorphic yeast that is part of the human skin microflora. This fungus is a pathogen of a certain skin diseases, such as pityriasis versicolor, and in rare cases causes systemic infection in neonates. However, the role of dimorphism in the pathogenicity remains unclear. A modified induction medium (IM) was successfully able to induce mycelial growth of M. furfur under both solid and liquid condition. Filamentous elements with branching hyphae were observed when cultured in the IM. Furthermore, addition of bovine fetus serum into the liquid IM did not promote hyphal formation; on the contrary, it retrograded hyphae to the yeast form. Plate-washing assay showed that M. furfur hyphae did not possess the ability of invasive growth. Secretory proteins from both yeast and hyphal forms were isolated, and lipase and protease activities were analyzed. Intriguingly, the hyphal form showed higher activities than those of the yeast form, particularly the protease activity.

  9. Effects of short-term caloric restriction on circulating free IGF-I, acid-labile subunit, IGF-binding proteins (IGFBPs)-1-4, and IGFBPs-1-3 protease activity in obese subjects

    DEFF Research Database (Denmark)

    Rasmussen, Michael Højby; Juul, Anders; Kjems, Lise Lund

    2006-01-01

    Decreased levels of GH and total IGF-I have been reported in obesity. It has been hypothesized that increased free (biologically active) IGF-I levels generated from IGF-binding protein (IGFBP) protease activity could be the mechanism for the low GH release in dieting obese subjects. However, no p...

  10. Effects of short-term caloric restriction on circulating free IGF-I, acid-labile subunit, IGF-binding proteins (IGFBPs)-1-4, and IGFBPs-1-3 protease activity in obese subjects

    DEFF Research Database (Denmark)

    Rasmussen, Michael Højby; Juul, Anders; Kjems, Lise Lund

    2006-01-01

    Decreased levels of GH and total IGF-I have been reported in obesity. It has been hypothesized that increased free (biologically active) IGF-I levels generated from IGF-binding protein (IGFBP) protease activity could be the mechanism for the low GH release in dieting obese subjects. However, no p...... a short-term very low-calorie diet (VLCD)....

  11. Cell-based fluorescence assay for human immunodeficiency virus type 1 protease activity

    Czech Academy of Sciences Publication Activity Database

    Lindsten, K.; Kondrová, Taťána; Konvalinka, Jan; Masucci, M. G.; Dantuma, N. P.

    2001-01-01

    Roč. 45, č. 9 (2001), s. 2616-2622 ISSN 0066-4804 R&D Projects: GA ČR GA303/98/1559 Grant - others:HHMI(US) 75195-540801; ECTM(XE) ERBFMRXCT960026 Institutional research plan: CEZ:AV0Z4055905 Keywords : HIV -1 * protease activity Subject RIV: CE - Biochemistry Impact factor: 4.562, year: 2001

  12. A novel protease activity assay using a protease-responsive chaperone protein

    Energy Technology Data Exchange (ETDEWEB)

    Sao, Kentaro [Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395 (Japan); Murata, Masaharu, E-mail: m-murata@dem.med.kyushu-u.ac.jp [Department of Advanced Medical Initiatives, Faculty of Medical Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku Fukuoka 812-8582 (Japan); Fujisaki, Yuri; Umezaki, Kaori [Department of Advanced Medical Initiatives, Faculty of Medical Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku Fukuoka 812-8582 (Japan); Mori, Takeshi; Niidome, Takuro; Katayama, Yoshiki [Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395 (Japan); Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Nishi-ku Fukuoka 819-0395 (Japan); Center for Future Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Hashizume, Makoto [Department of Advanced Medical Initiatives, Faculty of Medical Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku Fukuoka 812-8582 (Japan)

    2009-06-05

    Protease activity assays are important for elucidating protease function and for developing new therapeutic agents. In this study, a novel turbidimetric method for determining the protease activity using a protease-responsive chaperone protein is described. For this purpose, a recombinant small heat-shock protein (sHSP) with an introduced Factor Xa protease recognition site was synthesized in bacteria. This recombinant mutant, FXa-HSP, exhibited chaperone-like activity at high temperatures in cell lysates. However, the chaperone-like activity of FXa-HSP decreased dramatically following treatment with Factor Xa. Protein precipitation was subsequently observed in the cell lysates. The reaction was Factor Xa concentration-dependent and was quantitatively suppressed by a specific inhibitor for Factor Xa. Protein aggregation was detected by a simple method based on turbidimetry. The results clearly demonstrate that this assay is an effective, easy-to-use method for determining protease activities without the requirement of labeling procedures and the use of radioisotopes.

  13. The role of protease-activated receptor type 2 in nociceptive signaling and pain

    Czech Academy of Sciences Publication Activity Database

    Mrózková, Petra; Paleček, Jiří; Špicarová, Diana

    2016-01-01

    Roč. 65, č. 3 (2016), s. 357-367 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LH12058; GA ČR(CZ) GBP304/12/G069; GA ČR(CZ) GA15-11138S; GA MŠk(CZ) LH15279; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 Keywords : protease-activated receptor (PAR2) * signaling pathways * nociception * pain * spinal cord Subject RIV: FH - Neurology Impact factor: 1.461, year: 2016

  14. Characterization of the protease activity that cleaves the extracellular domain of β-dystroglycan

    International Nuclear Information System (INIS)

    Zhong Di; Saito, Fumiaki; Saito, Yuko; Nakamura, Ayami; Shimizu, Teruo; Matsumura, Kiichiro

    2006-01-01

    Dystroglycan (DG) complex, composed of αDG and βDG, provides a link between the extracellular matrix (ECM) and cortical cytoskeleton. Although the proteolytic processing of βDG was reported in various physiological and pathological conditions, its exact mechanism remains unknown. In this study, we addressed this issue using the cell culture system of rat schwannoma cell line RT4. We found that the culture medium of RT4 cells was enriched with the protease activity that degrades the fusion protein construct of the extracellular domain of βDG specifically. This activity was suppressed by the inhibitor of matrix metalloproteinase-2 (MMP-2) and MMP-9, but not by the inhibitors of MMP-1, MMP-3, MMP-8, and MMP-13. Zymography and RT-PCR analysis showed that RT4 cells secreted MMP-2 and MMP-9 into the culture medium. Finally, active MMP-2 and MMP-9 enzymes degraded the fusion protein construct of the extracellular domain of βDG. These results indicate (1) that RT4 cells secrete the protease activity that degrades the extracellular domain of βDG specifically and (2) that MMP-2 and MMP-9 may be involved in this process

  15. Protease-Activated Receptor 2: Are Common Functions in Glial and Immune Cells Linked to Inflammation-Related CNS Disorders?

    Science.gov (United States)

    Bushell, Trevor J; Cunningham, Margaret R; McIntosh, Kathryn A; Moudio, Serge; Plevin, Robin

    2016-01-01

    Protease-activated receptors (PARs) are a novel family of G-protein coupled receptors (GPCRs) whose activation requires the cleavage of the N-terminus by a serine protease. However, recent evidence reveals that alternative routes of activation also occur, that PARs signal via multiple pathways and that pathway activation is activator- dependent. Given our increased understanding of PAR function both under physiological and pathophysiological conditions, one aspect that has remained constant is the link between PAR2 and inflammation. PAR2 is expressed in immune cells of both the innate and adaptive immune system and has been shown to play a role in several peripheral inflammatory conditions. PAR2 is similarly expressed on astrocytes and microglia within the CNS and its activation is either protective or detrimental to CNS function depending on the conditions or disease state investigated. With a clear similarity between the function of PAR2 on both immune cells and CNS glial cells, here we have reviewed their roles in both these systems. We suggest that the recent development of novel PAR2 modulators, including those that show biased signalling, will further increase our understanding of PAR2 function and the development of potential therapeutics for CNS disorders in which inflammation is proposed to play a role.

  16. Protease-activated receptor-2 expression and the role of trypsin in cell proliferation in human pancreatic cancers.

    Science.gov (United States)

    Ohta, Tetsuo; Shimizu, Koichi; Yi, Shuangqin; Takamura, Hiroyuki; Amaya, Kohji; Kitagawa, Hirohisa; Kayahara, Masato; Ninomiya, Itasu; Fushida, Sachio; Fujimura, Takashi; Nishimura, Gen-Ichi; Miwa, Koichi

    2003-07-01

    Protease-activated receptor (PAR)-2 is a G protein-coupled receptor that is activated by trypsin. The purpose of this study was to examine PAR-2 expression and the role of trypsin in cell proliferation in human pancreatic cancer cells. All four pancreatic cancer cell lines studied, from well to undifferentiated types, AsPC-1, BxPC-3, Panc-1, and MIAPaCa-2, had significant levels of PAR-2 mRNA detected by reverse transcription-polymerase chain reaction, and showed a band of about 55 kDa corresponding to the known molecular weight of PAR-2: AsPC-1, BxPC-3 and Panc-1 showed a strong band, and MIAPaCa-2 showed a weak one. Immunocytochemically, AsPC-1, BxPC-3, and Panc-1 showed intense immunostaining for PAR-2, predominantly in the plasma membrane, while in MIAPaCa-2, immunostaining was weak. Proliferative activity of AsPC-1 cells was increased by concentrations of trypsin as low as 10 nM, and activity peaked at a concentration of 100 nM, representing almost 60% of that induced by 10% fetal bovine serum. In contrast, trypsin had no significant effect on proliferation of MIAPaCa-2 cells. These findings suggest that trypsin plays a role in the growth of PAR-2-positive pancreatic cancer cells and serves as a potent mitogen in vitro, functioning as a growth factor.

  17. Activation of Protease-Activated Receptor 2-Mediated Signaling by Mast Cell Tryptase Modulates Cytokine Production in Primary Cultured Astrocytes

    Directory of Open Access Journals (Sweden)

    Xiaoning Zeng

    2013-01-01

    Full Text Available Protease-activated receptor 2 (PAR-2, which is abundantly expressed in astrocytes, is known to play major roles in brain inflammation. However, the influence of the natural agonist of PAR-2, tryptase, on proinflammatory mediator releasedfrom astrocytes remains uninvestigated. In the present study, we found that tryptase at lower concentrations modestly reduced intracellular ROS production but significantly increased IL-6 and TNF-α secretion at higher concentrations without affecting astrocytic viability and proliferation. The actions of tryptase were alleviated by specific PAR-2 antagonist FSLLRY-NH2 (FS, indicating that the actions of tryptase were via PAR-2. PI3K/AKT inhibitor LY294002 reversed the effect of tryptase on IL-6 production, whereas inhibitors specific for p38, JNK, and ERK1/2 abolished the effect of tryptase on TNF-α production, suggesting that different signaling pathways are involved. Moreover, tryptase-induced activation of MAPKs and AKT was eliminated by FS, implicating that PAR-2 is responsible for transmitting tryptase biosignals to MAPKs and AKT. Tryptase provoked also expression of TGF-β and CNTF in astrocytes. The present findings suggest for the first time that tryptase can regulate the release of cytokines from astrocytes via PAR-2-MAPKs or PAR-2-PI3K/AKT signaling pathways, which reveals PAR-2 as a new target actively participating in the regulation of astrocytic functions.

  18. Differential regulation of protease activated receptor-1 and tissue plasminogen activator expression by shear stress in vascular smooth muscle cells

    Science.gov (United States)

    Papadaki, M.; Ruef, J.; Nguyen, K. T.; Li, F.; Patterson, C.; Eskin, S. G.; McIntire, L. V.; Runge, M. S.

    1998-01-01

    Recent studies have demonstrated that vascular smooth muscle cells are responsive to changes in their local hemodynamic environment. The effects of shear stress on the expression of human protease activated receptor-1 (PAR-1) and tissue plasminogen activator (tPA) mRNA and protein were investigated in human aortic smooth muscle cells (HASMCs). Under conditions of low shear stress (5 dyn/cm2), PAR-1 mRNA expression was increased transiently at 2 hours compared with stationary control values, whereas at high shear stress (25 dyn/cm2), mRNA expression was decreased (to 29% of stationary control; Pmuscle cells, indicating that the effects of shear stress on human PAR-1 were not species-specific. Flow cytometry and ELISA techniques using rat smooth muscle cells and HASMCs, respectively, provided evidence that shear stress exerted similar effects on cell surface-associated PAR-1 and tPA protein released into the conditioned media. The decrease in PAR-1 mRNA and protein had functional consequences for HASMCs, such as inhibition of [Ca2+] mobilization in response to thrombin stimulation. These data indicate that human PAR-1 and tPA gene expression are regulated differentially by shear stress, in a pattern consistent with their putative roles in several arterial vascular pathologies.

  19. Increased effects of machining damage in beryllium observed at high strain rates

    International Nuclear Information System (INIS)

    Beitscher, S.; Brewer, A.W.; Corle, R.R.

    1980-01-01

    Tensile tests at both low and high strain rates, and also impact shear tests, were performed on a weldable grade powder-source beryllium. Impact energies increased by a factor of 2 to 3 from the as-machined level after etching or annealing. Similar increases in the ductility from machining damage removal were observed from the tensile data at the higher strain rate (10 s -1 ) while an insignificant increase in elongation was measured at the lower strain rate (10 -4 s -1 ). High strain-rate tests appear to be more sensitive and reliable for evaluating machining practice and damage removal methods for beryllium components subjected to sudden loads. 2 tables

  20. The coagulation factor Xa/protease activated receptor-2 axis in the progression of liver fibrosis : a multifaceted paradigm

    NARCIS (Netherlands)

    Borensztajn, Keren; von der Thusen, Jan H.; Peppelenbosch, Maikel P.; Spek, C. Arnold

    2010-01-01

    Introduction Activation of the coagulation cascade during liver fibrosis: a puzzling paradox Protease-activated receptors: the link between coagulation cascade activation and liver fibrosis Expression and distribution of human PAR-2 in normal and pathological liver tissue FXa signalling on PAR-2

  1. Protease-Activated Receptor-2 Activation Contributes to House Dust Mite-Induced IgE Responses in Mice

    NARCIS (Netherlands)

    Post, Sijranke; Heijink, Irene; Petersen, A H; de Bruin, Harold G.; van Oosterhout, Antoon J. M.; Nawijn, Martijn C.

    2014-01-01

    Aeroallergens such as house dust mite (HDM), cockroach, and grass or tree pollen are innocuous substances that can induce allergic sensitization upon inhalation. The serine proteases present in these allergens are thought to activate the protease-activated receptor (PAR)-2, on the airway epithelium,

  2. Mutant E. coli strain with increased succinic acid production

    Science.gov (United States)

    Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    1998-01-01

    A method for isolating succinic acid producing bacteria is provided comprising increasing the biomass of an organism which lacks the ability to catabolize pyruvate, and then subjecting the biomass to glucose-rich medium in an anaerobic environment to enable pyruvate-catabolizing mutants to grow. The invention also provides for a mutant that produces high amounts of succinic acid, which as been derived from a parent which lacked the genes for pyruvate formate lyase and lactate dehydrogenase, and which belongs to the E.coli Group of Bacteria.

  3. Mutant E. coli strain with increased succinic acid production

    Science.gov (United States)

    Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    2001-09-25

    A method for isolating succinic acid producing bacteria is provided comprising increasing the biomass of an organism which lacks the ability to catabolize pyruvate, and then subjecting the biomass to glucose-rich medium in an anaerobic environment to enable pyruvate-catabolizing mutants to grow. The invention also provides for a mutant that produces high amounts of succinic acid, which has been derived from a parent which lacked the genes for pyruvate formate lyase and lactate dehydrogenase, and which belongs to the E.coli Group of Bacteria.

  4. Mast cell tryptase stimulates myoblast proliferation; a mechanism relying on protease-activated receptor-2 and cyclooxygenase-2

    Directory of Open Access Journals (Sweden)

    Côté Claude H

    2011-10-01

    Full Text Available Abstract Background Mast cells contribute to tissue repair in fibrous tissues by stimulating proliferation of fibroblasts through the release of tryptase which activates protease-activated receptor-2 (PAR-2. The possibility that a tryptase/PAR-2 signaling pathway exists in skeletal muscle cell has never been investigated. The aim of this study was to evaluate whether tryptase can stimulate myoblast proliferation and determine the downstream cascade. Methods Proliferation of L6 rat skeletal myoblasts stimulated with PAR-2 agonists (tryptase, trypsin and SLIGKV was assessed. The specificity of the tryptase effect was evaluated with a specific inhibitor, APC-366. Western blot analyses were used to evaluate the expression and functionality of PAR-2 receptor and to assess the expression of COX-2. COX-2 activity was evaluated with a commercial activity assay kit and by measurement of PGF2α production. Proliferation assays were also performed in presence of different prostaglandins (PGs. Results Tryptase increased L6 myoblast proliferation by 35% above control group and this effect was completely inhibited by APC-366. We confirmed the expression of PAR-2 receptor in vivo in skeletal muscle cells and in satellite cells and in vitro in L6 cells, where PAR-2 was found to be functional. Trypsin and SLIGKV increased L6 cells proliferation by 76% and 26% above control, respectively. COX-2 activity was increased following stimulation with PAR-2 agonist but its expression remained unchanged. Inhibition of COX-2 activity by NS-398 abolished the stimulation of cell proliferation induced by tryptase and trypsin. Finally, 15-deoxy-Δ-12,14-prostaglandin J2 (15Δ-PGJ2, a product of COX-2-derived prostaglandin D2, stimulated myoblast proliferation, but not PGE2 and PGF2α. Conclusions Taken together, our data show that tryptase can stimulate myoblast proliferation and this effect is part of a signaling cascade dependent on PAR-2 activation and on the downstream

  5. Increasing multidrug resistance in Helicobacter pylori strains isolated from children and adults in Mexico.

    Science.gov (United States)

    Torres, J; Camorlinga-Ponce, M; Pérez-Pérez, G; Madrazo-De la Garza, A; Dehesa, M; González-Valencia, G; Muñoz, O

    2001-07-01

    The susceptibilities to three antimicrobials of 195 Helicobacter pylori strains isolated from Mexican patients is reported; 80% of the strains were resistant to metronidazole, 24% were resistant to clarithromycin, and 18% presented a transient resistance to amoxicillin. Resistance to two or more antimicrobials increased significantly from 1995 to 1997.

  6. Increasing Multidrug Resistance in Helicobacter pylori Strains Isolated from Children and Adults in Mexico

    OpenAIRE

    Torres, Javier; Camorlinga-Ponce, Margarita; Pérez-Pérez, Guillermo; Madrazo-De la Garza, Armando; Dehesa, Margarita; González-Valencia, Gerardo; Muñoz, Onofre

    2001-01-01

    The susceptibilities to three antimicrobials of 195 Helicobacter pylori strains isolated from Mexican patients is reported; 80% of the strains were resistant to metronidazole, 24% were resistant to clarithromycin, and 18% presented a transient resistance to amoxicillin. Resistance to two or more antimicrobials increased significantly from 1995 to 1997.

  7. Interference with plastome gene expression and Clp protease activity in Arabidopsis triggers a chloroplast unfolded protein response to restore protein homeostasis.

    Science.gov (United States)

    Llamas, Ernesto; Pulido, Pablo; Rodriguez-Concepcion, Manuel

    2017-09-01

    Disruption of protein homeostasis in chloroplasts impairs the correct functioning of essential metabolic pathways, including the methylerythritol 4-phosphate (MEP) pathway for the production of plastidial isoprenoids involved in photosynthesis and growth. We previously found that misfolded and aggregated forms of the first enzyme of the MEP pathway are degraded by the Clp protease with the involvement of Hsp70 and Hsp100/ClpC1 chaperones in Arabidopsis thaliana. By contrast, the combined unfolding and disaggregating actions of Hsp70 and Hsp100/ClpB3 chaperones allow solubilization and hence reactivation of the enzyme. The repair pathway is promoted when the levels of ClpB3 proteins increase upon reduction of Clp protease activity in mutants or wild-type plants treated with the chloroplast protein synthesis inhibitor lincomycin (LIN). Here we show that LIN treatment rapidly increases the levels of aggregated proteins in the chloroplast, unleashing a specific retrograde signaling pathway that up-regulates expression of ClpB3 and other nuclear genes encoding plastidial chaperones. As a consequence, folding capacity is increased to restore protein homeostasis. This sort of chloroplast unfolded protein response (cpUPR) mechanism appears to be mediated by the heat shock transcription factor HsfA2. Expression of HsfA2 and cpUPR-related target genes is independent of GUN1, a central integrator of retrograde signaling pathways. However, double mutants defective in both GUN1 and plastome gene expression (or Clp protease activity) are seedling lethal, confirming that the GUN1 protein is essential for protein homeostasis in chloroplasts.

  8. DNA G-Wire Formation Using an Artificial Peptide is Controlled by Protease Activity.

    Science.gov (United States)

    Usui, Kenji; Okada, Arisa; Sakashita, Shungo; Shimooka, Masayuki; Tsuruoka, Takaaki; Nakano, Shu-Ichi; Miyoshi, Daisuke; Mashima, Tsukasa; Katahira, Masato; Hamada, Yoshio

    2017-11-16

    The development of a switching system for guanine nanowire (G-wire) formation by external signals is important for nanobiotechnological applications. Here, we demonstrate a DNA nanostructural switch (G-wire particles) using a designed peptide and a protease. The peptide consists of a PNA sequence for inducing DNA to form DNA-PNA hybrid G-quadruplex structures, and a protease substrate sequence acting as a switching module that is dependent on the activity of a particular protease. Micro-scale analyses via TEM and AFM showed that G-rich DNA alone forms G-wires in the presence of Ca 2+ , and that the peptide disrupted this formation, resulting in the formation of particles. The addition of the protease and digestion of the peptide regenerated the G-wires. Macro-scale analyses by DLS, zeta potential, CD, and gel filtration were in agreement with the microscopic observations. These results imply that the secondary structure change (DNA G-quadruplex DNA/PNA hybrid structure) induces a change in the well-formed nanostructure (G-wire particles). Our findings demonstrate a control system for forming DNA G-wire structures dependent on protease activity using designed peptides. Such systems hold promise for regulating the formation of nanowire for various applications, including electronic circuits for use in nanobiotechnologies.

  9. Protease-activated receptors and their biological role - focused on skin inflammation.

    Science.gov (United States)

    Guenther, Florian; Melzig, Matthias F

    2015-12-01

    For several years, protease-activated receptors (PARs) are targets of science regarding to various diseases and platelet aggregation. In the past, a number of publications related to PARs have been published, which refer to a variety of aspects. An important point of view is the inflammation of the skin, which has not been reported in detail yet. This review will provide an overview of the current knowledge on PARs, and in particular, on the involvement of PARs in terms of skin inflammation. Wound healing is an important step after skin injury and is connected with involvement of PARs and inflammation. An important point in skin inflammation is the coagulation-dependent skin inflammation. PARs are a special kind of receptors, being activated by proteolytic cleavage or chemical agonists. They may play an important role in various physiological processes. It is shown that the proteases are involved in many diseases for example Parkinson's disease and Alzheimer's disease. The fact, that proteases regulate the coagulation, and are involved in interleukin and cytokine release leads to the conclusion that they are involved in inflammation processes. © 2015 Royal Pharmaceutical Society.

  10. Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy.

    Science.gov (United States)

    Rwibasira Rudinga, Gamariel; Khan, Ghulam Jilany; Kong, Yi

    2018-02-14

    Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

  11. Protease-Activated Receptor 4 (PAR4: A Promising Target for Antiplatelet Therapy

    Directory of Open Access Journals (Sweden)

    Gamariel Rwibasira Rudinga

    2018-02-01

    Full Text Available Cardiovascular diseases (CVDs are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs, including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR. Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

  12. Nepenthesin protease activity indicates digestive fluid dynamics in carnivorous nepenthes plants.

    Directory of Open Access Journals (Sweden)

    Franziska Buch

    Full Text Available Carnivorous plants use different morphological features to attract, trap and digest prey, mainly insects. Plants from the genus Nepenthes possess specialized leaves called pitchers that function as pitfall-traps. These pitchers are filled with a digestive fluid that is generated by the plants themselves. In order to digest caught prey in their pitchers, Nepenthes plants produce various hydrolytic enzymes including aspartic proteases, nepenthesins (Nep. Knowledge about the generation and induction of these proteases is limited. Here, by employing a FRET (fluorescent resonance energy transfer-based technique that uses a synthetic fluorescent substrate an easy and rapid detection of protease activities in the digestive fluids of various Nepenthes species was feasible. Biochemical studies and the heterologously expressed Nep II from Nepenthes mirabilis proved that the proteolytic activity relied on aspartic proteases, however an acid-mediated auto-activation mechanism was necessary. Employing the FRET-based approach, the induction and dynamics of nepenthesin in the digestive pitcher fluid of various Nepenthes plants could be studied directly with insect (Drosophila melanogaster prey or plant material. Moreover, we observed that proteolytic activity was induced by the phytohormone jasmonic acid but not by salicylic acid suggesting that jasmonate-dependent signaling pathways are involved in plant carnivory.

  13. Nepenthesin protease activity indicates digestive fluid dynamics in carnivorous nepenthes plants.

    Science.gov (United States)

    Buch, Franziska; Kaman, Wendy E; Bikker, Floris J; Yilamujiang, Ayufu; Mithöfer, Axel

    2015-01-01

    Carnivorous plants use different morphological features to attract, trap and digest prey, mainly insects. Plants from the genus Nepenthes possess specialized leaves called pitchers that function as pitfall-traps. These pitchers are filled with a digestive fluid that is generated by the plants themselves. In order to digest caught prey in their pitchers, Nepenthes plants produce various hydrolytic enzymes including aspartic proteases, nepenthesins (Nep). Knowledge about the generation and induction of these proteases is limited. Here, by employing a FRET (fluorescent resonance energy transfer)-based technique that uses a synthetic fluorescent substrate an easy and rapid detection of protease activities in the digestive fluids of various Nepenthes species was feasible. Biochemical studies and the heterologously expressed Nep II from Nepenthes mirabilis proved that the proteolytic activity relied on aspartic proteases, however an acid-mediated auto-activation mechanism was necessary. Employing the FRET-based approach, the induction and dynamics of nepenthesin in the digestive pitcher fluid of various Nepenthes plants could be studied directly with insect (Drosophila melanogaster) prey or plant material. Moreover, we observed that proteolytic activity was induced by the phytohormone jasmonic acid but not by salicylic acid suggesting that jasmonate-dependent signaling pathways are involved in plant carnivory.

  14. Fluorescently labeled inhibitors detect localized serine protease activities in Drosophila melanogaster pole cells, embryos, and ovarian egg chambers

    DEFF Research Database (Denmark)

    Jakobsen, Rasmus Kragh; Ono, S.; Powers, J. C.

    2005-01-01

    processes that they mediate. Until only recently, the tools to conveniently address the question of where and when serine proteases are active within complex tissues have been lacking. In order to detect spatially restricted serine protease activities in Drosophila embryos and ovaries we introduce...... activity localized to the oocyte-somatic follicle cell interface of the developing egg chamber. Our results suggest that this technique holds promise to identify new spatially restricted activities in adult Drosophila tissues and developing embryos....

  15. A Comparative Study of New Aspergillus Strains for Proteolytic Enzymes Production by Solid State Fermentation

    Directory of Open Access Journals (Sweden)

    Gastón Ezequiel Ortiz

    2016-01-01

    Full Text Available A comparative study of the proteolytic enzymes production using twelve Aspergillus strains previously unused for this purpose was performed by solid state fermentation. A semiquantitative and quantitative evaluation of proteolytic activity were carried out using crude enzymatic extracts obtained from the fermentation cultures, finding seven strains with high and intermediate level of protease activity. Biochemical, thermodynamics, and kinetics features such as optimum pH and temperature values, thermal stability, activation energy (Ea, quotient energy (Q10, Km, and Vmax were studied in four enzymatic extracts from the selected strains that showed the highest productivity. Additionally, these strains were evaluated by zymogram analysis obtaining protease profiles with a wide range of molecular weight for each sample. From these four strains with the highest productivity, the proteolytic extract of A. sojae ATCC 20235 was shown to be an appropriate biocatalyst for hydrolysis of casein and gelatin substrates, increasing its antioxidant activities in 35% and 125%, respectively.

  16. EFFECTIVE FRACTURE ENERGY OF ULTRA-HIGH-PERFORMANCE FIBRE-REINFORCED CONCRETE UNDER INCREASED STRAIN RATES

    Directory of Open Access Journals (Sweden)

    Radoslav Sovják

    2014-10-01

    Full Text Available The main objective of this paper is to contribute to the development of ultra-high performance fibre reinforced concrete (UHPFRC with respect to its effective fracture energy. Effective fracture energy was investigated in this paper considering different fibre volume fractions and different strain rates. It was concluded that the effective fracture energy is dependent on the strain rate. In addition, it was found that higher fibre volume fractions tend to decrease the sensitivity of the UHPFRC to increased strain rates.

  17. Protease-activated receptor-2 activation exaggerates TRPV1-mediated cough in guinea pigs.

    Science.gov (United States)

    Gatti, Raffaele; Andre, Eunice; Amadesi, Silvia; Dinh, Thai Q; Fischer, Axel; Bunnett, Nigel W; Harrison, Selena; Geppetti, Pierangelo; Trevisani, Marcello

    2006-08-01

    A lowered threshold to the cough response frequently accompanies chronic airway inflammatory conditions. However, the mechanism(s) that from chronic inflammation results in a lowered cough threshold is poorly understood. Irritant agents, including capsaicin, resiniferatoxin, and citric acid, elicit cough in humans and in experimental animals through the activation of the transient receptor potential vanilloid 1 (TRPV1). Protease-activated receptor-2 (PAR2) activation plays a role in inflammation and sensitizes TRPV1 in cultured sensory neurons by a PKC-dependent pathway. Here, we have investigated whether PAR2 activation exaggerates TRPV1-dependent cough in guinea pigs and whether protein kinases are involved in the PAR2-induced cough modulation. Aerosolized PAR2 agonists (PAR2-activating peptide and trypsin) did not produce any cough per se. However, they potentiated citric acid- and resiniferatoxin-induced cough, an effect that was completely prevented by the TRPV1 receptor antagonist capsazepine. In contrast, cough induced by hypertonic saline, a stimulus that provokes cough in a TRPV1-independent manner, was not modified by aerosolized PAR2 agonists. The PKC inhibitor GF-109203X, the PKA inhibitor H-89, and the cyclooxygenase inhibitor indomethacin did not affect cough induced by TRPV1 agonists, but abated the exaggeration of this response produced by PAR2 agonists. In conclusion, PAR2 stimulation exaggerates TRPV1-dependent cough by activation of diverse mechanism(s), including PKC, PKA, and prostanoid release. PAR2 activation, by sensitizing TRPV1 in primary sensory neurons, may play a role in the exaggerated cough observed in certain airways inflammatory diseases such as asthma and chronic obstructive pulmonary disease.

  18. Macelignan inhibits melanosome transfer mediated by protease-activated receptor-2 in keratinocytes.

    Science.gov (United States)

    Choi, Eun-Jung; Kang, Young-Gyu; Kim, Jaekyung; Hwang, Jae-Kwan

    2011-01-01

    Skin pigmentation is the result of melanosome transfer from melanocytes to keratinocytes. Protease-activated receptor-2 (PAR-2) is a key mediator of melanosome transfer, which occurs as the melanocyte extends its dendrite toward surrounding keratinocytes that take up melanosomes by phagocytosis. We investigated the effects of macelignan isolated from Myristica fragrans HOUTT. (nutmeg) on melanosome transfer and the regulation of PAR-2 in human keratinocytes (HaCaT). HaCaT cells stimulated by the PAR-2-activating peptide Ser-Leu-Ile-Gly-Arg-Leu-NH₂ (SLIGRL) were treated with macelignan; PAR-2 expression was then determined by reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and immunocytochemistry. We evaluated the effects of macelignan on calcium mobilization and keratinocyte phagocytosis. In addition, B16F10 melanoma cells and keratinocytes were co-cultured to assess the effects of macelignan on prostaglandin E₂ (PGE₂) secretion and subsequent dendrite formation. Macelignan decreased HaCaT PAR-2 mRNA and protein levels in a dose-dependent manner. Furthermore, macelignan markedly reduced intracellular calcium mobilization and significantly downregulated keratinocyte phagocytosis, as shown by decreased ingestion of Escherichia coli bioparticles and fluorescent microspheres. In co-culture experiments, macelignan reduced keratinocyte PGE₂ secretion, thereby preventing dendrite formation in B16F10 melanoma cells compared with SLIGRL-treated controls. Macelignan inhibits melanosome transfer by downregulating PAR-2, thereby reducing keratinocyte phagocytosis and PGE₂ secretion, which in turn inhibits dendrite formation in B16F10 melanoma cells. Taken together, our findings suggest that macelignan could be used as a natural depigmenting agent to ameliorate hyperpigmentation.

  19. Protease-Activated Receptor 4 Induces Bladder Pain through High Mobility Group Box-1.

    Directory of Open Access Journals (Sweden)

    Dimitrios E Kouzoukas

    Full Text Available Pain is the significant presenting symptom in Interstitial Cystitis/Painful Bladder Syndrome (IC/PBS. Activation of urothelial protease activated receptor 4 (PAR4 causes pain through release of urothelial macrophage migration inhibitory factor (MIF. High Mobility Group Box-1 (HMGB1, a chromatin-binding protein, mediates bladder pain (but not inflammation in an experimental model (cyclophosphamide of cystitis. To determine if PAR4-induced bladder hypersensitivity depends on HMGB1 downstream, we tested whether: 1 bladder PAR4 stimulation affected urothelial HMGB1 release; 2 blocking MIF inhibited urothelial HMGB1 release; and 3 blocking HMGB1 prevented PAR4-induced bladder hypersensitivity. HMGB1 release was examined in immortalized human urothelial cultures (UROtsa exposed to PAR4-activating peptide (PAR4-AP; 100 μM; 2 hours or scrambled control peptide. Female C57BL/6 mice, pretreated with a HMGB1 inhibitor (glycyrrhizin: 50 mg/kg; i.p. or vehicle, received intravesical PAR4-AP or a control peptide (100 μM; 1 hour to determine 1 HMGB1 levels at 1 hour in the intravesical fluid (released HMGB1 and urothelium, and 2 abdominal hypersensitivity to von Frey filament stimulation 24 hours later. We also tested mice pretreated with a MIF blocker (ISO-1: 20 mg/kg; i.p. to determine whether MIF mediated PAR4-induced urothelial HMGB1 release. PAR4-AP triggered HMGB1 release from human (in vitro and mice (in vivo urothelial cells. Intravesical PAR4 activation elicited abdominal hypersensitivity in mice that was prevented by blocking HMGB1. MIF inhibition prevented PAR4-mediated HMGB1 release from mouse urothelium. Urothelial MIF and HGMB1 represent novel targets for therapeutic intervention in bladder pain conditions.

  20. Protease-activated receptor 1-dependent neuronal damage involves NMDA receptor function.

    Science.gov (United States)

    Hamill, Cecily E; Mannaioni, Guido; Lyuboslavsky, Polina; Sastre, Aristide A; Traynelis, Stephen F

    2009-05-01

    Protease-activated receptor 1 (PAR1) is a G-protein coupled receptor that is expressed throughout the central nervous system. PAR1 activation by brain-derived as well as blood-derived proteases has been shown to have variable and complex effects in a variety of animal models of neuronal injury and inflammation. In this study, we have evaluated the effects of PAR1 on lesion volume in wild-type or PAR1-/- C57Bl/6 mice subjected to transient occlusion of the middle cerebral artery or injected with NMDA in the striatum. We found that removal of PAR1 reduced infarct volume following transient focal ischemia to 57% of control. Removal of PAR1 or application of a PAR1 antagonist also reduced the neuronal injury associated with intrastriatal injection of NMDA to 60% of control. To explore whether NMDA receptor potentiation by PAR1 activation contributes to the harmful effects of PAR1, we investigated the effect of NMDA receptor antagonists on the neuroprotective phenotype of PAR1-/- mice. We found that MK801 reduced penumbral but not core neuronal injury in mice subjected to transient middle cerebral artery occlusion or intrastriatal NMDA injection. Lesion volumes in both models were not significantly different between PAR1-/- mice treated with and without MK801. Use of the NMDA receptor antagonist and dissociative anesthetic ketamine also renders NMDA-induced lesion volumes identical in PAR1-/- mice and wild-type mice. These data suggest that the ability of PAR1 activation to potentiate NMDA receptor function may underlie its harmful actions during injury.

  1. Protease-activated receptor 2 mediates mucus secretion in the airway submucosal gland.

    Directory of Open Access Journals (Sweden)

    Hyun Jae Lee

    Full Text Available Protease-activated receptor 2 (PAR2, a G protein-coupled receptor expressed in airway epithelia and smooth muscle, plays an important role in airway inflammation. In this study, we demonstrated that activation of PAR2 induces mucus secretion from the human airway gland and examined the underlying mechanism using the porcine and murine airway glands. The mucosa with underlying submucosal glands were dissected from the cartilage of tissues, pinned with the mucosal side up at the gas/bath solution interface of a physiological chamber, and covered with oil so that secretions from individual glands could be visualized as spherical bubbles in the oil. Secretion rates were determined by optical monitoring of the bubble diameter. The Ca(2+-sensitive dye Fura2-AM was used to determine intracellular Ca(2+ concentration ([Ca(2+](i by means of spectrofluorometry. Stimulation of human tracheal mucosa with PAR2-activating peptide (PAR2-AP elevated intracellular Ca(2+ and induced glandular secretion equal to approximately 30% of the carbachol response in the human airway. Porcine gland tissue was more sensitive to PAR2-AP, and this response was dependent on Ca(2+ and anion secretion. When the mouse trachea were exposed to PAR2-AP, large amounts of secretion were observed in both wild type and ΔF508 cystic fibrosis transmembrane conductance regulator mutant mice but there is no secretion from PAR-2 knock out mice. In conclusion, PAR2-AP is an agonist for mucus secretion from the airway gland that is Ca(2+-dependent and cystic fibrosis transmembrane conductance regulator-independent.

  2. Methylene blue not ferrocene: Optimal reporters for electrochemical detection of protease activity.

    Science.gov (United States)

    González-Fernández, Eva; Avlonitis, Nicolaos; Murray, Alan F; Mount, Andrew R; Bradley, Mark

    2016-10-15

    Electrochemical peptide-based biosensors are attracting significant attention for the detection and analysis of proteins. Here we report the optimisation and evaluation of an electrochemical biosensor for the detection of protease activity using self-assembled monolayers (SAMs) on gold surfaces, using trypsin as a model protease. The principle of detection was the specific proteolytic cleavage of redox-tagged peptides by trypsin, which causes the release of the redox reporter, resulting in a decrease of the peak current as measured by square wave voltammetry. A systematic enhancement of detection was achieved through optimisation of the properties of the redox-tagged peptide; this included for the first time a side-by-side study of the applicability of two of the most commonly applied redox reporters used for developing electrochemical biosensors, ferrocene and methylene blue, along with the effect of changing both the nature of the spacer and the composition of the SAM. Methylene blue-tagged peptides combined with a polyethylene-glycol (PEG) based spacer were shown to be the best platform for trypsin detection, leading to the highest fidelity signals (characterised by the highest sensitivity (signal gain) and a much more stable background than that registered when using ferrocene as a reporter). A ternary SAM (T-SAM) configuration, which included a PEG-based dithiol, minimised the non-specific adsorption of other proteins and was sensitive towards trypsin in the clinically relevant range, with a Limit of Detection (LoD) of 250pM. Kinetic analysis of the electrochemical response with time showed a good fit to a Michaelis-Menten surface cleavage model, enabling the extraction of values for kcat and KM. Fitting to this model enabled quantitative determination of the solution concentration of trypsin across the entire measurement range. Studies using an enzyme inhibitor and a range of real world possible interferents demonstrated a selective response to trypsin

  3. Protease-activated receptor-2 turnover stimulated independently of receptor activation in porcine coronary endothelial cells

    Science.gov (United States)

    Hamilton, Justin R; Chow, Jean M; Cocks, Thomas M

    1999-01-01

    Protease-activated receptors (PARs) are activated by an irreversible proteolytic mechanism which renders cleaved receptors unresponsive to subsequent challenges with activating enzymes. Non-specific proteolysis of PARs downstream of the activation site also prevents subsequent enzymic activation. Therefore, we investigated the effects of non-activating amino-terminal proteolysis with the bacterial protease thermolysin on PAR-mediated relaxation of porcine coronary artery ring preparations contracted with the thromboxane A2 mimetic U46619 (1–10 nM). Treatment of contracted artery ring segments with thermolysin (0.01–1 u ml−1, 20 min) caused no response, but abolished endothelium-dependent relaxations induced by the enzymic activators of PAR-1 and PAR-2, thrombin (0.01–0.3 u ml−1) and trypsin (0.003–0.1 u ml−1) respectively. The same treatment, however, did not affect similar responses to the proteolysis-independent PAR-1 and PAR-2 activating peptides, SFLLRN-NH2 and SLIGRL-NH2 respectively (0.1–10 μM). The inhibition of responsiveness to trypsin after thermolysin treatment recovered in a time-dependent manner, with maximal recovery (77.3±8.0% of time controls) occurring 150 min after thermolysin treatment. No recovery of responsiveness to thrombin after thermolysin treatment was observed within this time, however, the thrombin response returned to control levels after 20 h. The recovery of responsiveness to trypsin was inhibited by the translation inhibitor cycloheximide (100 μM; 17.3±4.7%) and the protein trafficking inhibitor brefeldin A (10 μM; 12.1±4.8%) but was unaffected by the transcription inhibitor actinomycin D (2 μM; 65.1±3.6%), which did, however, abolish upregulation of B1-kinin receptors in this preparation. In conclusion, our findings indicate that activation-independent amino-terminal proteolysis of PARs stimulates selective recovery of endothelial cell PAR-2 responsiveness, which appears to be

  4. Screening of phytochemicals against protease activated receptor 1 (PAR1), a promising target for cancer.

    Science.gov (United States)

    Kakarala, Kavita Kumari; Jamil, Kaiser

    2015-02-01

    Drug resistance and drug-associated toxicity are the primary causes for withdrawal of many drugs, although patient recovery is satisfactory in many instances. Interestingly, the use of phytochemicals in the treatment of cancer as an alternative to synthetic drugs comes with a host of advantages; minimum side effects, good human absorption and low toxicity to normal cells. Protease activated receptor 1 (PAR1) has been established as a promising target in many diseases including various cancers. Strong evidences suggest its role in metastasis also. There are no natural compounds known to inhibit its activity, so we aimed to identify phytochemicals with antagonist activity against PAR1. We screened phytochemicals from Naturally Occurring Plant-based Anticancer Compound-Activity-Target database (NPACT, http://crdd.osdd.net/raghava/npact/ ) against PAR1 using virtual screening workflow of Schrödinger software. It analyzes pharmaceutically relevant properties using Qikprop and calculates binding energy using Glide at three accuracy levels (high-throughput virtual screening, standard precision and extra precision). Our study led to the identification of phytochemicals, which showed interaction with at least one experimentally determined active site residue of PAR1, showed no violations to Lipinski's rule of five along with predicted high human absorption. Furthermore, structural interaction fingerprint analysis indicated that the residues H255, D256, E260, S344, V257, L258, L262, Y337 and S344 may play an important role in the hydrogen bond interactions of the phytochemicals screened. Of these residues, H255 and L258 residues were experimentally proved to be important for antagonist binding. The residues Y183, L237, L258, L262, F271, L332, L333, Y337, L340, A349, Y350, A352, and Y353 showed maximum hydrophobic interactions with the phytochemicals screened. The results of this work suggest that phytochemicals Reissantins D, 24,25-dihydro-27-desoxywithaferin A, Isoguaiacin

  5. Optimization of protease production by an actinomycete Strain, PS ...

    African Journals Online (AJOL)

    Actinomycetes were isolated from the sediment samples of an estuarine shrimp pond located along the south east coast of India. During the investigation, a total of 28 strains of actinomycetes were isolated and examined for their protease activity. Among them, one strain PS-18A which was tentatively identified as ...

  6. Activated factor X signaling via protease-activated receptor 2 suppresses pro-inflammatory cytokine production from LPS-stimulated myeloid cells.

    LENUS (Irish Health Repository)

    Gleeson, Eimear M

    2013-07-19

    Vitamin K-dependent proteases generated in response to vascular injury and infection enable fibrin clot formation, but also trigger distinct immuno-regulatory signaling pathways on myeloid cells. Factor Xa, a protease crucial for blood coagulation, also induces protease-activated receptor-dependent cell signaling. Factor Xa can bind both monocytes and macrophages, but whether factor Xa-dependent signaling stimulates or suppresses myeloid cell cytokine production in response to Toll-like receptor activation is not known. In this study, exposure to factor Xa significantly impaired pro-inflammatory cytokine production from lipopolysaccharide-treated peripheral blood mononuclear cells, THP-1 monocytic cells and murine macrophages. Furthermore, factor Xa inhibited nuclear factor-kappa B activation in THP-1 reporter cells, requiring phosphatidylinositide 3-kinase activity for its anti-inflammatory effect. Active-site blockade, γ-carboxyglutamic acid domain truncation and a peptide mimic of the factor Xa inter-epidermal growth factor-like region prevented factor Xa inhibition of lipopolysaccharide-induced tumour necrosis factor-α release. In addition, factor Xa anti-inflammatory activity was markedly attenuated by the presence of an antagonist of protease-activated receptor 2, but not protease-activated receptor 1. The key role of protease-activated receptor 2 in eliciting factor Xa-dependent anti-inflammatory signaling on macrophages was further underscored by the inability of factor Xa to mediate inhibition of tumour necrosis factor-α and interleukin-6 release from murine bone marrow-derived protease-activated receptor 2-deficient macrophages. We also show for the first time that, in addition to protease-activated receptor 2, factor Xa requires a receptor-associated protein-sensitive low-density lipoprotein receptor to inhibit lipopolysaccharide-induced cytokine production. Collectively, this study supports a novel function for factor Xa as an endogenous, receptor

  7. Cathelicidin, kallikrein 5, and serine protease activity is inhibited during treatment of rosacea with azelaic acid 15% gel.

    Science.gov (United States)

    Coda, Alvin B; Hata, Tissa; Miller, Jeremiah; Audish, David; Kotol, Paul; Two, Aimee; Shafiq, Faiza; Yamasaki, Kenshi; Harper, Julie C; Del Rosso, James Q; Gallo, Richard L

    2013-10-01

    Excess cathelicidin and kallikrein 5 (KLK5) have been hypothesized to play a role in the pathophysiology of rosacea. We sought to evaluate the effects of azelaic acid (AzA) on these elements of the innate immune system. Gene expression and protease activity were measured in laboratory models and patients with rosacea during a 16-week multicenter, prospective, open-label study of 15% AzA gel. AzA directly inhibited KLK5 in cultured keratinocytes and gene expression of KLK5, Toll-like receptor-2, and cathelicidin in mouse skin. Patients with rosacea showed reduction in cathelicidin and KLK5 messenger RNA after treatment with AzA gel. Subjects without rosacea had lower serine protease activity (SPA) than patients with rosacea. Distinct subsets of patients with rosacea who had high and low baseline SPA were identified, and patients with high baseline exhibited a statistically significant reduction of SPA with 15% AzA gel treatment. Study size was insufficient to predict clinical efficacy based on the innate immune response to AzA. These results show that cathelicidin and KLK5 decrease in association with AZA exposure. Our observations suggest a new mechanism of action for AzA and that SPA may be a useful biomarker for disease activity. Copyright © 2013 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  8. Cathelicidin, kallikrein 5, and serine protease activity is inhibited during treatment of rosacea with azelaic acid 15% gel

    Science.gov (United States)

    Coda, Alvin B.; Hata, Tissa; Miller, Jeremiah; Audish, David; Kotol, Paul; Two, Aimee; Shafiq, Faiza; Yamasaki, Kenshi; Harper, Julie C.; Del Rosso, James Q.; Gallo, Richard L.

    2014-01-01

    Background Excess cathelicidin and kallikrein 5 (KLK5) have been hypothesized to play a role in the pathophysiology of rosacea. Objective We sought to evaluate the effects of azelaic acid (AzA) on these elements of the innate immune system. Methods Gene expression and protease activity were measured in laboratory models and patients with rosacea during a 16-week multicenter, prospective, open-label study of 15% AzA gel. Results AzA directly inhibited KLK5 in cultured keratinocytes and gene expression of KLK5, Toll-like receptor-2, and cathelicidin in mouse skin. Patients with rosacea showed reduction in cathelicidin and KLK5 messenger RNA after treatment with AzA gel. Subjects without rosacea had lower serine protease activity (SPA) than patients with rosacea. Distinct subsets of patients with rosacea who had high and low baseline SPA were identified, and patients with high baseline exhibited a statistically significant reduction of SPA with 15% AzA gel treatment. Limitations Study size was insufficient to predict clinical efficacy based on the innate immune response to AzA. Conclusions These results show that cathelicidin and KLK5 decrease in association with AZA exposure. Our observations suggest a new mechanism of action for AzA and that SPA may be a useful biomarker for disease activity. PMID:23871720

  9. Blood pressures, heart rate and locomotor activity during salt loading and angiotensin II infusion in protease-activated receptor 2 (PAR2 knockout mice

    Directory of Open Access Journals (Sweden)

    Halfyard Sarah J

    2008-10-01

    Full Text Available Abstract Background In this study we used radiotelemetry to measure hemodynamic variables and locomotor activity in conscious unrestrained male Protease-Activated Receptor 2 (PAR-2 knockout mice in order to provide a detailed assessment of their blood pressure phenotype. In addition we tested for an influence of PAR-2 on salt-sensitivity (8% versus 0.5% NaCl diet, 2.5 weeks and angiotensin II-induced hypertension (1 μg Ile5-angiotensin II/kg/min versus 0.25 μl/h saline, 2 weeks. Results Systolic arterial pressures of PAR-2 -/- (129 ± 1 mmHg, n = 21, P P Conclusion The data indicated gene knockout of PAR-2 was associated with a modest change in blood pressure phenotype. PAR-2 -/- mice exhibited moderate elevation of systolic arterial and pulse pressures, yet no increased diastolic arterial pressure, no increased blood pressure responses to high salt diet and a subtle difference in the time course of the blood pressure responses to angiotensin II infusion.

  10. Enhanced Effector Function of CD8+ T Cells From Healthy Controls and HIV-Infected Patients Occurs Through Thrombin Activation of Protease-Activated Receptor 1

    Science.gov (United States)

    Hurley, Amanda; Smith, Mindy; Karpova, Tatiana; Hasley, Rebecca B.; Belkina, Natalya; Shaw, Stephen; Balenga, Nariman; Druey, Kirk M.; Nickel, Erin; Packard, Beverly; Imamichi, Hiromi; Hu, Zonghui; Follmann, Dean; McNally, James; Higgins, Jeanette; Sneller, Michael; Lane, H. Clifford; Catalfamo, Marta

    2013-01-01

    Disruption of vascular integrity by trauma and other tissue insults leads to inflammation and activation of the coagulation cascade. The serine protease thrombin links these 2 processes. The proinflammatory function of thrombin is mediated by activation of protease-activated receptor 1 (PAR-1). We found that peripheral blood effector memory CD4+ and CD8+ T lymphocytes expressed PAR-1 and that expression was increased in CD8+ T cells from human immunodeficiency virus (HIV)–infected patients. Thrombin enhanced cytokine secretion in CD8+ T cells from healthy controls and HIV-infected patients. In addition, thrombin induced chemokinesis, but not chemotaxis, of CD8+ T cells, which led to structural changes, including cell polarization and formation of a structure rich in F-actin and phosphorylated ezrin-radexin-moesin proteins. These findings suggest that thrombin mediates cross-talk between the coagulation system and the adaptive immune system at sites of vascular injury through increased T-cell motility and production of proinflammatory cytokines. PMID:23204166

  11. Enhanced effector function of CD8(+) T cells from healthy controls and HIV-infected patients occurs through thrombin activation of protease-activated receptor 1.

    Science.gov (United States)

    Hurley, Amanda; Smith, Mindy; Karpova, Tatiana; Hasley, Rebecca B; Belkina, Natalya; Shaw, Stephen; Balenga, Nariman; Druey, Kirk M; Nickel, Erin; Packard, Beverly; Imamichi, Hiromi; Hu, Zonghui; Follmann, Dean; McNally, James; Higgins, Jeanette; Sneller, Michael; Lane, H Clifford; Catalfamo, Marta

    2013-02-15

    Disruption of vascular integrity by trauma and other tissue insults leads to inflammation and activation of the coagulation cascade. The serine protease thrombin links these 2 processes. The proinflammatory function of thrombin is mediated by activation of protease-activated receptor 1 (PAR-1). We found that peripheral blood effector memory CD4(+) and CD8(+) T lymphocytes expressed PAR-1 and that expression was increased in CD8(+) T cells from human immunodeficiency virus (HIV)-infected patients. Thrombin enhanced cytokine secretion in CD8(+) T cells from healthy controls and HIV-infected patients. In addition, thrombin induced chemokinesis, but not chemotaxis, of CD8(+) T cells, which led to structural changes, including cell polarization and formation of a structure rich in F-actin and phosphorylated ezrin-radexin-moesin proteins. These findings suggest that thrombin mediates cross-talk between the coagulation system and the adaptive immune system at sites of vascular injury through increased T-cell motility and production of proinflammatory cytokines.

  12. Protease-Activated Receptor 1 and Hematopoietic Cell Tissue Factor Are Required for Hepatic Steatosis in Mice Fed a Western Diet

    Science.gov (United States)

    Kassel, Karen M.; Owens, A. Phillip; Rockwell, Cheryl E.; Sullivan, Bradley P.; Wang, Ruipeng; Tawfik, Ossama; Li, Guodong; Guo, Grace L.; Mackman, Nigel; Luyendyk, James P.

    2011-01-01

    Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of obesity and metabolic syndrome and contributes to increased risk of cardiovascular disease and liver-related morbidity and mortality. Indeed, obese patients with metabolic syndrome generate greater amounts of thrombin, an indication of coagulation cascade activation. However, the role of the coagulation cascade in Western diet–induced NAFLD has not been investigated. Using an established mouse model of Western diet–induced NAFLD, we tested whether the thrombin receptor protease-activated receptor 1 (PAR-1) and hematopoietic cell–derived tissue factor (TF) contribute to hepatic steatosis. In association with hepatic steatosis, plasma thrombin-antithrombin levels and hepatic fibrin deposition increased significantly in C57Bl/6J mice fed a Western diet for 3 months. PAR-1 deficiency reduced hepatic inflammation, particularly monocyte chemoattractant protein-1 expression and macrophage accumulation. In addition, PAR-1 deficiency was associated with reduced steatosis in mice fed a Western diet, including reduced liver triglyceride accumulation and CD36 expression. Similar to PAR-1 deficiency, hematopoietic cell TF deficiency was associated with reduced inflammation and reduced steatosis in livers of low-density lipoprotein receptor–deficient mice fed a Western diet. Moreover, hematopoietic cell TF deficiency reduced hepatic fibrin deposition. These studies indicate that PAR-1 and hematopoietic cell TF are required for liver inflammation and steatosis in mice fed a Western diet. PMID:21907177

  13. Protease-activated receptor 1 and hematopoietic cell tissue factor are required for hepatic steatosis in mice fed a Western diet.

    Science.gov (United States)

    Kassel, Karen M; Owens, A Phillip; Rockwell, Cheryl E; Sullivan, Bradley P; Wang, Ruipeng; Tawfik, Ossama; Li, Guodong; Guo, Grace L; Mackman, Nigel; Luyendyk, James P

    2011-11-01

    Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of obesity and metabolic syndrome and contributes to increased risk of cardiovascular disease and liver-related morbidity and mortality. Indeed, obese patients with metabolic syndrome generate greater amounts of thrombin, an indication of coagulation cascade activation. However, the role of the coagulation cascade in Western diet-induced NAFLD has not been investigated. Using an established mouse model of Western diet-induced NAFLD, we tested whether the thrombin receptor protease-activated receptor 1 (PAR-1) and hematopoietic cell-derived tissue factor (TF) contribute to hepatic steatosis. In association with hepatic steatosis, plasma thrombin-antithrombin levels and hepatic fibrin deposition increased significantly in C57Bl/6J mice fed a Western diet for 3 months. PAR-1 deficiency reduced hepatic inflammation, particularly monocyte chemoattractant protein-1 expression and macrophage accumulation. In addition, PAR-1 deficiency was associated with reduced steatosis in mice fed a Western diet, including reduced liver triglyceride accumulation and CD36 expression. Similar to PAR-1 deficiency, hematopoietic cell TF deficiency was associated with reduced inflammation and reduced steatosis in livers of low-density lipoprotein receptor-deficient mice fed a Western diet. Moreover, hematopoietic cell TF deficiency reduced hepatic fibrin deposition. These studies indicate that PAR-1 and hematopoietic cell TF are required for liver inflammation and steatosis in mice fed a Western diet. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  14. NMDA-receptor inhibition restores Protease-Activated Receptor 1 (PAR1) mediated alterations in homeostatic synaptic plasticity of denervated mouse dentate granule cells.

    Science.gov (United States)

    Becker, Denise; Ikenberg, Benno; Schiener, Sabine; Maggio, Nicola; Vlachos, Andreas

    2014-11-01

    A common feature of neurological diseases is the loss of central neurons, which leads to deafferentation of connected brain regions. In turn, the remodeling of denervated neuronal networks is considered to play an important role for the postlesional recovery, but has also been linked to maladaptive plasticity resulting in disease-related complications such as memory dysfunction or epilepsy. Recent work has indicated that Protease-Activated Receptor 1 (PAR1), which can be activated by thrombin that enters the brain under pathological conditions, alters synaptic plasticity and neuronal excitability. However, the role of PAR1 in lesion-induced synaptic plasticity remains incompletely understood. Here, we used entorhinal denervation of organotypic hippocampal slice cultures to study the effects of PAR1 on denervation-induced homeostatic synaptic plasticity. Our results disclose that PAR1 activation counters the ability of denervated dentate granule cells to increase their excitatory synaptic strength in a compensatory, i.e., homeostatic manner. Furthermore, we demonstrate that this PAR1 effect is rescued by pharmacological inhibition of N-methyl-d-aspartate receptors (NMDA-R). Thus, NMDA-R inhibitors may restore the ability of denervated neurons to express homeostatic synaptic plasticity under conditions of increased PAR1-activity, which may contribute to their beneficial effects seen in the context of neurological diseases. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Protease-activated receptor-1 negatively regulates proliferation of neural stem/progenitor cells derived from the hippocampal dentate gyrus of the adult mouse

    Directory of Open Access Journals (Sweden)

    Masayuki Tanaka

    2016-07-01

    Full Text Available Thrombin-activated protease-activated receptor (PAR-1 regulates the proliferation of neural cells following brain injury. To elucidate the involvement of PAR-1 in the neurogenesis that occurs in the adult hippocampus, we examined whether PAR-1 regulated the proliferation of neural stem/progenitor cells (NPCs derived from the murine hippocampal dentate gyrus. NPC cultures expressed PAR-1 protein and mRNA encoding all subtypes of PAR. Direct exposure of the cells to thrombin dramatically attenuated the cell proliferation without causing cell damage. This thrombin-induced attenuation was almost completely abolished by the PAR antagonist RWJ 56110, as well as by dabigatran and 4-(2-aminoethylbenzenesulfonyl fluoride (AEBSF, which are selective and non-selective thrombin inhibitors, respectively. Expectedly, the PAR-1 agonist peptide (AP SFLLR-NH2 also attenuated the cell proliferation. The cell proliferation was not affected by the PAR-1 negative control peptide RLLFT-NH2, which is an inactive peptide for PAR-1. Independently, we determined the effect of in vivo treatment with AEBSF or AP on hippocampal neurogenesis in the adult mouse. The administration of AEBSF, but not that of AP, significantly increased the number of newly-generated cells in the hippocampal subgranular zone. These data suggest that PAR-1 negatively regulated adult neurogenesis in the hippocampus by inhibiting the proliferative activity of the NPCs.

  16. Increasing the scale of peroxidase production by Streptomyces sp. strain BSII#1.

    Science.gov (United States)

    Musengi, A; Khan, N; Le Roes-Hill, M; Pletschke, B I; Burton, S G

    2014-03-01

    To optimize peroxidase production by Streptomyces sp. strain BSII#1, up to 3 l culture volumes. Peroxidase production by Streptomyces sp. strain BSII#1 was optimized in terms of production temperature and pH and the use of lignin-based model chemical inducers. The highest peroxidase activity (1·30 ± 0·04 U ml(-1) ) in 10 ml culture volume was achieved in a complex production medium (pH 8·0) at 37°C in the presence of 0·1 mmol l(-1) veratryl alcohol, which was greater than those reported previously. Scale-up to 100 and 400 ml culture volumes resulted in decreased peroxidase production (0·53 ± 0·10 and 0·26 ± 0·08 U ml(-1) , respectively). However, increased aeration improved peroxidase production with the highest production achieved using an airlift bioreactor (4·76 ± 0·46 U ml(-1) in 3 l culture volume). Veratryl alcohol (0·1 mmol l(-1) ) is an effective inducer of peroxidase production by Streptomyces sp. strain BSII#1. However, improved aeration increased peroxidase production in larger volumes without the use of an inducer, surpassing induced yields in an optimized small-scale process. Only a limited number of reports in literature have focused on the up-scaling of bacterial peroxidase production. There remains opportunity for feasible large-scale production of bacterial peroxidases with potentially novel biocatalytic properties. © 2013 The Society for Applied Microbiology.

  17. Human osteoblast-like cells respond to mechanical strain with increased bone matrix protein production independent of hormonal regulation

    Science.gov (United States)

    Harter, L. V.; Hruska, K. A.; Duncan, R. L.

    1995-01-01

    Exposure of osteosarcoma cell lines to chronic intermittent strain increases the activity of mechano-sensitive cation (SA-cat) channels. The impact of mechano-transduction on osteoblast function has not been well studied. We analyzed the expression and production of bone matrix proteins in human osteoblast-like osteosarcoma cells, OHS-4, in response to chronic intermittent mechanical strain. The OHS-4 cells exhibit type I collagen production, 1,25-Dihydroxyvitamin D-inducible osteocalcin, and mineralization of the extracellular matrix. The matrix protein message level was determined from total RNA isolated from cells exposed to 1-4 days of chronic intermittent strain. Northern analysis for type I collagen indicated that strain increased collagen message after 48 h. Immunofluorescent labeling of type I collagen demonstrated that secretion was also enhanced with mechanical strain. Osteopontin message levels were increased several-fold by the application of mechanical load in the absence of vitamin D, and the two stimuli together produced an additive effect. Osteocalcin secretion was also increased with cyclic strain. Osteocalcin levels were not detectable in vitamin D-untreated control cells. However, after 4 days of induced load, significant levels of osteocalcin were observed in the medium. With vitamin D present, osteocalcin levels were 4 times higher in the medium of strained cells compared to nonstrained controls. We conclude that mechanical strain of osteoblast-like cells is sufficient to increase the transcription and secretion of matrix proteins via mechano-transduction without hormonal induction.

  18. Site-SpecificCu Labeling of the Serine Protease, Active Site Inhibited Factor Seven Azide (FVIIai-N), Using Copper Free Click Chemistry

    DEFF Research Database (Denmark)

    Jeppesen, Troels E; Kristensen, Lotte K; Nielsen, Carsten H

    2018-01-01

    A method for site-specific radiolabeling of the serine protease active site inhibited factor seven (FVIIai) with64Cu has been applied using a biorthogonal click reaction. FVIIai binds to tissue factor (TF), a trans-membrane protein involved in hemostasis, angiogenesis, proliferation, cell migrati...

  19. Determination of the protease cleavage site repertoire—The RNase H but not the RT domain is essential for foamy viral protease activity

    Energy Technology Data Exchange (ETDEWEB)

    Spannaus, Ralf; Bodem, Jochen, E-mail: Jochen.Bodem@vim.uni-wuerzburg.de

    2014-04-15

    In contrast to orthoretroviruses, the foamy virus protease is only active as a protease-reverse transcriptase fusion protein and requires viral RNA for activation. Maturation of foamy viral proteins seems to be restricted to a single cleavage site in Gag and Pol. We provide evidence that unprocessed Gag is required for optimal infectivity, which is unique among retroviruses. Analyses of the cleavage site sequences of the Gag and Pol cleavage sites revealed a high similarity compared to those of Lentiviruses. We show that positions P2' and P2 are invariant and that Gag and Pol cleavage sites are processed with similar efficiencies. The RNase H domain is essential for protease activity, but can functionally be substituted by RNase H domains of other retroviruses. Thus, the RNase H domain might be involved in the stabilization of the protease dimer, while the RT domain is essential for RNA dependent protease activation. - Highlights: • Unprocessed Gag is required for optimal infectivity of foamy viruses. • Positions P2 and P2' are invariant in the foamy viral cleavage sites. • The RNaseH domain is essential for protease activity. • The RNaseH domains of other retroviruses support foamy viral protease activity.

  20. Determination of the protease cleavage site repertoire—The RNase H but not the RT domain is essential for foamy viral protease activity

    International Nuclear Information System (INIS)

    Spannaus, Ralf; Bodem, Jochen

    2014-01-01

    In contrast to orthoretroviruses, the foamy virus protease is only active as a protease-reverse transcriptase fusion protein and requires viral RNA for activation. Maturation of foamy viral proteins seems to be restricted to a single cleavage site in Gag and Pol. We provide evidence that unprocessed Gag is required for optimal infectivity, which is unique among retroviruses. Analyses of the cleavage site sequences of the Gag and Pol cleavage sites revealed a high similarity compared to those of Lentiviruses. We show that positions P2' and P2 are invariant and that Gag and Pol cleavage sites are processed with similar efficiencies. The RNase H domain is essential for protease activity, but can functionally be substituted by RNase H domains of other retroviruses. Thus, the RNase H domain might be involved in the stabilization of the protease dimer, while the RT domain is essential for RNA dependent protease activation. - Highlights: • Unprocessed Gag is required for optimal infectivity of foamy viruses. • Positions P2 and P2' are invariant in the foamy viral cleavage sites. • The RNaseH domain is essential for protease activity. • The RNaseH domains of other retroviruses support foamy viral protease activity

  1. Galectin-3 facilitates cell motility in gastric cancer by up-regulating protease-activated receptor-1 (PAR-1 and matrix metalloproteinase-1 (MMP-1.

    Directory of Open Access Journals (Sweden)

    Seok-Jun Kim

    Full Text Available BACKGROUND: Galectin-3 is known to regulate cancer metastasis. However, the underlying mechanism has not been defined. Through the DNA microarray studies after galectin-3 silencing, we demonstrated here that galectin-3 plays a key role in up-regulating the expressions of protease-activated receptor-1 (PAR-1 and matrix metalloproteinase-1 (MMP-1 PAR-1 thereby promoting gastric cancer metastasis. METHODOLOGY/PRINCIPAL FINDINGS: We examined the expression levels of Galectin-3, PAR-1, and MMP-1 in gastric cancer patient tissues and also the effects of silencing these proteins with specific siRNAs and of over-expressing them using specific lenti-viral constructs. We also employed zebrafish embryo model for analysis of in vivo gastric cancer cell invasion. These studies demonstrated that: a galectin-3 silencing decreases the expression of PAR-1. b galectin-3 over-expression increases cell migration and invasion and this increase can be reversed by PAR-1 silencing, indicating that galectin-3 increases cell migration and invasion via PAR-1 up-regulation. c galectin-3 directly interacts with AP-1 transcriptional factor, and this complex binds to PAR-1 promoter and drives PAR-1 transcription. d galectin-3 also amplifies phospho-paxillin, a PAR-1 downstream target, by increasing MMP-1 expression. MMP-1 silencing blocks phospho-paxillin amplification and cell invasion caused by galectin-3 over-expression. e Silencing of either galectin-3, PAR-1 or MMP-1 significantly reduced cell migration into the vessels in zebrafish embryo model. f Galectin-3, PAR-1, and MMP-1 are highly expressed and co-localized in malignant tissues from gastric cancer patients. CONCLUSIONS/SIGNIFICANCE: Galectin-3 plays the key role of activating cell surface receptor through production of protease and boosts gastric cancer metastasis. Galectin-3 has the potential to serve as a useful pharmacological target for prevention of gastric cancer metastasis.

  2. Increasing rate of daptomycin non-susceptible strains of Staphylococcus aureus in patients with atopic dermatitis

    Directory of Open Access Journals (Sweden)

    Izabela Błażewicz

    2017-12-01

    Full Text Available Introduction : Daptomycin is a cyclic lipopeptide that is bactericidal against Staphylococcus aureus , including methicillin-resistant S. aureus (MRSA, vancomycin-intermediate S. aureus (VISA and vancomycin-resistant S. aureus (VRSA strains. Daptomycin exerts its antimicrobial effect by a calcium-dependent interaction with the cytoplasmic membrane resulting in depolarization, ion loss and rapid cell death. Unfortunately, loss of daptomycin susceptibility in S. aureus in the clinical setting has been noted. Aim : To evaluate the susceptibility profile to daptomycin among S. aureus strains isloted from patients with atopic dermatitis (AD. Another point was to correlate the results obtained by broth microdilution method and Etest, which is commonly applied in clinical setting. Material and methods : One hundred patients with the diagnosis of atopic dermatitis were microbiologically assessed for the carriage of S. aureus . Antimicrobial susceptibility tests were performed using broth-microdilution (BMD and Etests for daptomycin. Results : Staphylococcus aureus strains were isolated from the majority of our patients, either from the skin (73% or the anterior nares (75%. Six of the 100 nasal swabs (6% and 5 of the 100 skin swabs (5% were positive for methicillin-resistant Staphylococcus aureus (MRSA. A total of 81 of 148 (54.7% daptomycin non-susceptible isolates of S. aureus were identified by BMD. Only 19 of 81 were also classified as non-susceptible by Etest. Conclusions : Clinicians and microbiologists should be aware of the possibility of the emergence of daptomycin non-susceptibility (or increase in minimal inhibitory concentration during prolonged therapy and closely monitor the susceptibility of persisting isolates that might be recovered during therapy.

  3. Increasing antibiotic resistance in preservative-tolerant bacterial strains isolated from cosmetic products.

    Science.gov (United States)

    Orús, Pilar; Gomez-Perez, Laura; Leranoz, Sonia; Berlanga, Mercedes

    2015-03-01

    To ensure the microbiological quality, consumer safety and organoleptic properties of cosmetic products, manufacturers need to comply with defined standards using several preservatives and disinfectants. A drawback regarding the use of these preservatives is the possibility of generating cross-insusceptibility to other disinfectants or preservatives, as well as cross resistance to antibiotics. Therefore, the objective of this study was to understand the adaptive mechanisms of Enterobacter gergoviae, Pseudomonas putida and Burkholderia cepacia that are involved in recurrent contamination in cosmetic products containing preservatives. Diminished susceptibility to formaldehyde-donors was detected in isolates but not to other preservatives commonly used in the cosmetics industry, although increasing resistance to different antibiotics (β-lactams, quinolones, rifampicin, and tetracycline) was demonstrated in these strains when compared with the wild-type strain. The outer membrane protein modifications and efflux mechanism activities responsible for the resistance trait were evaluated. The development of antibiotic-resistant microorganisms due to the selective pressure from preservatives included in cosmetic products could be a risk for the emergence and spread of bacterial resistance in the environment. Nevertheless, the large contribution of disinfection and preservation cannot be denied in cosmetic products. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  4. Method for construction of bacterial strains with increased succinic acid production

    Science.gov (United States)

    Donnelly, Mark I.; Sanville-Millard, Cynthia; Chatterjee, Ranjini

    2000-01-01

    A fermentation process for producing succinic acid is provided comprising selecting a bacterial strain that does not produce succinic acid in high yield, disrupting the normal regulation of sugar metabolism of said bacterial strain, and combining the mutant bacterial strain and selected sugar in anaerobic conditions to facilitate production of succinic acid. Also provided is a method for changing low yield succinic acid producing bacteria to high yield succinic acid producing bacteria comprising selecting a bacterial strain having a phosphotransferase system and altering the phosphotransferase system so as to allow the bacterial strain to simultaneously metabolize different sugars.

  5. A Lactobacillus rhamnosus strain induces a heme oxygenase dependent increase in Foxp3+ regulatory T cells.

    Directory of Open Access Journals (Sweden)

    Khalil Karimi

    Full Text Available We investigated the consequences of feeding with a Lactobacillus species on the immune environment in GALT, and the role of dendritic cells and heme oxygenase-1 in mediating these responses. Feeding with a specific strain of Lactobacillus rhamnosus induced a significant increase in CD4+CD25+Foxp3+ functional regulatory T cells in GALT. This increase was greatest in the mesenteric lymph nodes and associated with a marked decrease in TNF and IFNγ production. Dendritic cell regulatory function and HO-1 expression was also increased. The increase in Foxp3+ T cells could be prevented by treatment with a heme oxygenase inhibitor. However, neither inhibition of heme oxygenase nor blockade of IL-10 and TGFβ prevented the inhibition of inflammatory cytokine production. In conclusion Lactobacillus feeding induced a tolerogenic environment in GALT. HO-1 was critical to the enhancement of Foxp3+ regulatory T cells while additional, as yet unknown, pathways were involved in the down-regulation of inflammatory cytokine production by T cells.

  6. Adaptor Protein Complex-2 (AP-2) and Epsin-1 Mediate Protease-activated Receptor-1 Internalization via Phosphorylation- and Ubiquitination-dependent Sorting Signals*

    Science.gov (United States)

    Chen, Buxin; Dores, Michael R.; Grimsey, Neil; Canto, Isabel; Barker, Breann L.; Trejo, JoAnn

    2011-01-01

    Signaling by protease-activated receptor-1 (PAR1), a G protein-coupled receptor (GPCR) for thrombin, is regulated by desensitization and internalization. PAR1 desensitization is mediated by β-arrestins, like most classic GPCRs. In contrast, internalization of PAR1 occurs through a clathrin- and dynamin-dependent pathway independent of β-arrestins. PAR1 displays two modes of internalization. Constitutive internalization of unactivated PAR1 is mediated by the clathrin adaptor protein complex-2 (AP-2), where the μ2-adaptin subunit binds directly to a tyrosine-based motif localized within the receptor C-tail domain. However, AP-2 depletion only partially inhibits agonist-induced internalization of PAR1, suggesting a function for other clathrin adaptors in this process. Here, we now report that AP-2 and epsin-1 are both critical mediators of agonist-stimulated PAR1 internalization. We show that ubiquitination of PAR1 and the ubiquitin-interacting motifs of epsin-1 are required for epsin-1-dependent internalization of activated PAR1. In addition, activation of PAR1 promotes epsin-1 de-ubiquitination, which may increase its endocytic adaptor activity to facilitate receptor internalization. AP-2 also regulates activated PAR1 internalization via recognition of distal C-tail phosphorylation sites rather than the canonical tyrosine-based motif. Thus, AP-2 and epsin-1 are both required to promote efficient internalization of activated PAR1 and recognize discrete receptor sorting signals. This study defines a new pathway for internalization of mammalian GPCRs. PMID:21965661

  7. Regulation of protease-activated receptor 1 signaling by the adaptor protein complex 2 and R4 subfamily of regulator of G protein signaling proteins.

    Science.gov (United States)

    Chen, Buxin; Siderovski, David P; Neubig, Richard R; Lawson, Mark A; Trejo, Joann

    2014-01-17

    The G protein-coupled protease-activated receptor 1 (PAR1) is irreversibly proteolytically activated by thrombin. Hence, the precise regulation of PAR1 signaling is important for proper cellular responses. In addition to desensitization, internalization and lysosomal sorting of activated PAR1 are critical for the termination of signaling. Unlike most G protein-coupled receptors, PAR1 internalization is mediated by the clathrin adaptor protein complex 2 (AP-2) and epsin-1, rather than β-arrestins. However, the function of AP-2 and epsin-1 in the regulation of PAR1 signaling is not known. Here, we report that AP-2, and not epsin-1, regulates activated PAR1-stimulated phosphoinositide hydrolysis via two different mechanisms that involve, in part, a subset of R4 subfamily of "regulator of G protein signaling" (RGS) proteins. A significantly greater increase in activated PAR1 signaling was observed in cells depleted of AP-2 using siRNA or in cells expressing a PAR1 (420)AKKAA(424) mutant with defective AP-2 binding. This effect was attributed to AP-2 modulation of PAR1 surface expression and efficiency of G protein coupling. We further found that ectopic expression of R4 subfamily members RGS2, RGS3, RGS4, and RGS5 reduced activated PAR1 wild-type signaling, whereas signaling by the PAR1 AKKAA mutant was minimally affected. Intriguingly, siRNA-mediated depletion analysis revealed a function for RGS5 in the regulation of signaling by the PAR1 wild type but not the AKKAA mutant. Moreover, activation of the PAR1 wild type, and not the AKKAA mutant, induced Gαq association with RGS3 via an AP-2-dependent mechanism. Thus, AP-2 regulates activated PAR1 signaling by altering receptor surface expression and through recruitment of RGS proteins.

  8. Diallylsulfide attenuates excessive collagen production and apoptosis in a rat model of bleomycin induced pulmonary fibrosis through the involvement of protease activated receptor-2

    International Nuclear Information System (INIS)

    Kalayarasan, Srinivasan; Sriram, Narayanan; Soumyakrishnan, Syamala; Sudhandiran, Ganapasam

    2013-01-01

    Pulmonary fibrosis (PF) can be a devastating lung disease. It is primarily caused by inflammation leading to severe damage of the alveolar epithelial cells. The pathophysiology of PF is not yet been clearly defined, but studying lung parenchymal injury by involving reactive oxygen species (ROS) through the activation of protease activated receptor-2 (PAR-2) may provide promising results. PAR-2 is a G-protein coupled receptor is known to play an important role in the development of PF. In this study, we investigated the inhibitory role of diallylsulfide (DAS) against ROS mediated activation of PAR-2 and collagen production accompanied by epithelial cell apoptosis. Bleomycin induced ROS levels may prompt to induce the expression of PAR-2 as well as extracellular matrix proteins (ECM), such as MMP 2 and 9, collagen specific proteins HSP-47, α-SMA, and cytokines IL-6, and IL-8RA. Importantly DAS treatment effectively decreased the expression of all these proteins. The inhibitory effect of DAS on profibrotic molecules is mediated by blocking the ROS level. To identify apoptotic signaling as a mediator of PF induction, we performed apoptotic protein expression, DNA fragmentation analysis and ultrastructural details of the lung tissue were performed. DAS treatment restored all these changes to near normalcy. In conclusion, treatment of PF bearing rats with DAS results in amelioration of the ROS production, PAR-2 activation, ECM production, collagen synthesis and alveolar epithelial cell apoptosis during bleomycin induction. We attained the first evidence that treatment of DAS decreases the ROS levels and may provide a potential therapeutic effect attenuating bleomycin induced PF. - Highlights: • DAS inhibits PAR-2 activity; bleomycin stimulates PAR-2 activity. • Increase in PAR-2 activity is correlated with pulmonary fibrosis • DAS reduces pro-inflammatory activity linked to facilitating pulmonary fibrosis. • DAS inhibits apoptosis of alveolar epithelial cells

  9. An improved labeling strategy enables automated detection of single-virus fusion and assessment of HIV-1 protease activity in single virions.

    Science.gov (United States)

    Sood, Chetan; Francis, Ashwanth C; Desai, Tanay M; Melikyan, Gregory B

    2017-12-08

    Enveloped viruses transfer their genomes into host cells by fusing their membrane to that of the cell. To visualize single-virus fusion in living cells, researchers take advantage of the proteolytic maturation of HIV, type 1 (HIV-1), which can generate free fluorescent proteins within the viral particle. Co-labeling viruses with a content marker and a fluorescently tagged Vpr (a viral core protein) enables detection of single-virus fusions, but a major limitation of this approach is that not all viral particles incorporate both markers. Here we designed a labeling strategy based on the bifunctional mCherry-2xCL-YFP-Vpr construct, in which 2xCL denotes a tandem cleavage site for the viral protease. This bifunctional marker was efficiently cleaved during virus maturation, producing free mCherry and the core-associated YFP-Vpr. A nearly perfect colocalization of these two markers in virions and their fixed 1:1 ratio enabled automated detection of single-particle fusion in both fixed and live cells based on loss of the mCherry signal. Furthermore, a drop in FRET efficiency between YFP and mCherry because of cleavage of the bifunctional marker, which manifested as a marked shift in the normalized YFP/mCherry fluorescence ratio, reliably predicted viral protease activity in single virions. This feature could discriminate between the particles containing free mCherry, and therefore likely representing mature viruses, and immature particles whose fusion cannot be detected. In summary, our new labeling strategy offers several advantages compared with previous approaches, including increased reliability and throughput of detection of viral fusion. We anticipate that our method will have significant utility for studying viral fusion and maturation. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Diallylsulfide attenuates excessive collagen production and apoptosis in a rat model of bleomycin induced pulmonary fibrosis through the involvement of protease activated receptor-2

    Energy Technology Data Exchange (ETDEWEB)

    Kalayarasan, Srinivasan, E-mail: kalaivasanbio@gmail.com; Sriram, Narayanan; Soumyakrishnan, Syamala; Sudhandiran, Ganapasam, E-mail: sudhandiran@yahoo.com

    2013-09-01

    Pulmonary fibrosis (PF) can be a devastating lung disease. It is primarily caused by inflammation leading to severe damage of the alveolar epithelial cells. The pathophysiology of PF is not yet been clearly defined, but studying lung parenchymal injury by involving reactive oxygen species (ROS) through the activation of protease activated receptor-2 (PAR-2) may provide promising results. PAR-2 is a G-protein coupled receptor is known to play an important role in the development of PF. In this study, we investigated the inhibitory role of diallylsulfide (DAS) against ROS mediated activation of PAR-2 and collagen production accompanied by epithelial cell apoptosis. Bleomycin induced ROS levels may prompt to induce the expression of PAR-2 as well as extracellular matrix proteins (ECM), such as MMP 2 and 9, collagen specific proteins HSP-47, α-SMA, and cytokines IL-6, and IL-8RA. Importantly DAS treatment effectively decreased the expression of all these proteins. The inhibitory effect of DAS on profibrotic molecules is mediated by blocking the ROS level. To identify apoptotic signaling as a mediator of PF induction, we performed apoptotic protein expression, DNA fragmentation analysis and ultrastructural details of the lung tissue were performed. DAS treatment restored all these changes to near normalcy. In conclusion, treatment of PF bearing rats with DAS results in amelioration of the ROS production, PAR-2 activation, ECM production, collagen synthesis and alveolar epithelial cell apoptosis during bleomycin induction. We attained the first evidence that treatment of DAS decreases the ROS levels and may provide a potential therapeutic effect attenuating bleomycin induced PF. - Highlights: • DAS inhibits PAR-2 activity; bleomycin stimulates PAR-2 activity. • Increase in PAR-2 activity is correlated with pulmonary fibrosis • DAS reduces pro-inflammatory activity linked to facilitating pulmonary fibrosis. • DAS inhibits apoptosis of alveolar epithelial cells.

  11. Protease-activated receptor (PAR2, but not PAR1, is involved in collateral formation and anti-inflammatory monocyte polarization in a mouse hind limb ischemia model.

    Directory of Open Access Journals (Sweden)

    Lisa G van den Hengel

    Full Text Available AIMS: In collateral development (i.e. arteriogenesis, mononuclear cells are important and exist as a heterogeneous population consisting of pro-inflammatory and anti-inflammatory/repair-associated cells. Protease-activated receptor (PAR1 and PAR2 are G-protein-coupled receptors that are both expressed by mononuclear cells and are involved in pro-inflammatory reactions, while PAR2 also plays a role in repair-associated responses. Here, we investigated the physiological role of PAR1 and PAR2 in arteriogenesis in a murine hind limb ischemia model. METHODS AND RESULTS: PAR1-deficient (PAR1-/-, PAR2-deficient (PAR2-/- and wild-type (WT mice underwent femoral artery ligation. Laser Doppler measurements revealed reduced post-ischemic blood flow recovery in PAR2-/- hind limbs when compared to WT, while PAR1-/- mice were not affected. Upon ischemia, reduced numbers of smooth muscle actin (SMA-positive collaterals and CD31-positive capillaries were found in PAR2-/- mice when compared to WT mice, whereas these parameters in PAR1-/- mice did not differ from WT mice. The pool of circulating repair-associated (Ly6C-low monocytes and the number of repair-associated (CD206-positive macrophages surrounding collaterals in the hind limbs were increased in WT and PAR1-/- mice, but unaffected in PAR2-/- mice. The number of repair-associated macrophages in PAR2-/- hind limbs correlated with CD11b- and CD115-expression on the circulating monocytes in these animals, suggesting that monocyte extravasation and M-CSF-dependent differentiation into repair-associated cells are hampered. CONCLUSION: PAR2, but not PAR1, is involved in arteriogenesis and promotes the repair-associated response in ischemic tissues. Therefore, PAR2 potentially forms a new pro-arteriogenic target in coronary artery disease (CAD patients.

  12. Two mutations associated with macrolide resistance in Treponema pallidum: increasing prevalence and correlation with molecular strain type in Seattle, Washington.

    Science.gov (United States)

    Grimes, Matthew; Sahi, Sharon K; Godornes, B Charmie; Tantalo, Lauren C; Roberts, Neal; Bostick, David; Marra, Christina M; Lukehart, Sheila A

    2012-12-01

    Although azithromycin promised to be a safe and effective single-dose oral treatment of early syphilis, azithromycin treatment failure has been documented and is associated with mutations in the 23S rDNA of corresponding Treponema pallidum strains. The prevalence of strains harboring these mutations varies throughout the United States and the world. We examined T. pallidum strains circulating in Seattle, Washington, from 2001 to 2010 to determine the prevalence of 2 mutations associated with macrolide resistance and to determine whether these mutations were associated with certain T. pallidum strain types. Subjects were enrolled in a separate ongoing study of cerebrospinal fluid abnormalities in patients with syphilis. T. pallidum DNA purified from blood and T. pallidum strains isolated from blood or cerebrospinal fluid were analyzed for two 23S rDNA mutations and for the molecular targets used in an enhanced molecular stain typing system. Nine molecular strain types of T. pallidum were identified in Seattle from 2001 to 2010. Both macrolide resistance mutations were identified in Seattle strains, and the prevalence of resistant T. pallidum exceeded 80% in 2005 and increased through 2010. Resistance mutations were associated with discrete molecular strain types of T. pallidum. Macrolide-resistant T. pallidum strains are highly prevalent in Seattle, and each mutation is associated with discrete strain types. Macrolides should not be considered for treatment of syphilis in regions where prevalence of the mutations is high. Combining the resistance mutations with molecular strain typing permits a finer analysis of the epidemiology of syphilis in a community.

  13. Molecular cloning of canine protease-activated receptor-2 and its expression in normal dog tissues and atopic skin lesions.

    Science.gov (United States)

    Maeda, Shingo; Maeda, Sadatoshi; Shibata, Sanae; Chimura, Naoki; Fukata, Tsuneo

    2009-05-01

    Protease-activated receptor-2 (PAR-2) belongs to a new G protein-coupled receptor subfamily and is activated by serine proteases. PAR-2 has been demonstrated to play an important role in inflammation and immune response in allergic diseases. In this study, we cloned canine PAR-2 cDNA from the canine kidney by RT-PCR. The canine PAR-2 clone contained a full-length open reading frame encoding 397 amino acids that had 84% and 80% homology with human and mouse homologues, respectively. Canine PAR-2 mRNA was detected in the heart, lung, liver, pancreas, stomach, small intestine, colon, kidney, adrenal gland, spleen, thyroid gland, thymus, skeletal muscle, lymph node, fat and skin of three healthy dogs. The expression pattern of PAR-2 mRNA in canine tissues was similar to that in humans. The expression level of PAR-2 mRNA in skin was not different between the atopic dermatitis (AD) and healthy dogs, suggesting that the level of PAR-2 mRNA transcription may not be associated with development of canine AD. The canine PAR-2 cDNA clone obtained in this study will be useful for further investigation of the immunopathogenesis of canine allergic diseases.

  14. Protease activity in the larval stage of the parasitoid wasp, Eulophus pennicornis (Nees) (Hymenoptera: Eulophidae); effects of protease inhibitors.

    Science.gov (United States)

    Down, R E; Ford, L; Mosson, H J; Fitches, E; Gatehouse, J A; Gatehouse, A M

    1999-08-01

    Hymenopteran, parasitoid wasps have good potential for use in integrated pest management (IPM); for example, the gregarious ectoparasitoid, Eulophus pennicornis, has been suggested as a biological control agent for larvae of the tomato moth (Lacanobia oleracea L.). However, the processes by which such parasitic larvae are able to utilize the nutritional resource provided by the host have been little studied. Protease activity was present in E. pennicornis larvae, and characterization of the enzymes responsible for proteolysis was performed using a range of synthetic substrates and specific inhibitors. Serine protease enzymes was both trypsin- and chymotrypsin-like activities were present. A range of plant-derived serine protease inhibitors was tested for activity against these enzymes. Certain inhibitors, notably soybean Kunitz inhibitor (SKTI), inhibited enzyme activity by > 80% at < 10(-5) M. When SKTI was fed to L. oleracea larvae in an artificial diet, the inhibitor was subsequently detected within the larval haemolymph, showing that protease inhibitors in the host diet can be delivered to a parasitoid via the host haemolymph. If transgenic plants expressing foreign protease inhibitors for protection against insect pests are to form a component of IPM systems, possible adverse effects, whether direct or indirect, of transgene expression on parasitoids like E. pennicornis should be considered.

  15. Interspecies differences in membrane-associated protease activities of thyrocytes and their relevance for thyroid cancer studies

    Directory of Open Access Journals (Sweden)

    Fröhlich Eleonore

    2012-05-01

    Full Text Available Abstract Background To understand the role of proteases involved in human thyroid cancer progression and tissue invasion, thyrocytes from other species could potentially be used provided their characteristics are similar. It is not known whether dipeptidyl peptidase IV and aminopeptidase N activities, which are overexpressed in human thyroid cancer, are, as in human, also absent in normal thyrocytes of other species, making them suitable models for studies on the regulation of these proteases. Methods To assess the role of these proteases, activity was measured in thyroid tissue of human, mouse, rat, porcine, bovine and ovine origin. The lysosomal protease, dipeptidyl peptidase II, was used for comparison. Results Murine, rat, ovine, bovine and human thyrocytes all lacked dipeptidyl peptidase IV and aminopeptidase N activity, but porcine thyrocytes were found to possess both. In contrast, lysosomal dipeptidyl peptidase II was strongly expressed in all species. These activity patterns were maintained in cultured cells. Cultured porcine thyrocytes formed follicles with typical morphology upon stimulation with TSH but differed from human thyrocytes in their response to thiamazole. Conclusions These species differences in the expression of dipeptidyl peptidase IV and aminopeptidase N, indicate that porcine thyrocytes cannot be considered appropriate for the study of proteases in human cancer development.

  16. The Inflammasome Drives GSDMD-Independent Secondary Pyroptosis and IL-1 Release in the Absence of Caspase-1 Protease Activity.

    Science.gov (United States)

    Schneider, Katharina S; Groß, Christina J; Dreier, Roland F; Saller, Benedikt S; Mishra, Ritu; Gorka, Oliver; Heilig, Rosalie; Meunier, Etienne; Dick, Mathias S; Ćiković, Tamara; Sodenkamp, Jan; Médard, Guillaume; Naumann, Ronald; Ruland, Jürgen; Kuster, Bernhard; Broz, Petr; Groß, Olaf

    2017-12-26

    Inflammasomes activate the protease caspase-1, which cleaves interleukin-1β and interleukin-18 to generate the mature cytokines and controls their secretion and a form of inflammatory cell death called pyroptosis. By generating mice expressing enzymatically inactive caspase-1 C284A , we provide genetic evidence that caspase-1 protease activity is required for canonical IL-1 secretion, pyroptosis, and inflammasome-mediated immunity. In caspase-1-deficient cells, caspase-8 can be activated at the inflammasome. Using mice either lacking the pyroptosis effector gasdermin D (GSDMD) or expressing caspase-1 C284A , we found that GSDMD-dependent pyroptosis prevented caspase-8 activation at the inflammasome. In the absence of GSDMD-dependent pyroptosis, the inflammasome engaged a delayed, alternative form of lytic cell death that was accompanied by the release of large amounts of mature IL-1 and contributed to host protection. Features of this cell death modality distinguished it from apoptosis, suggesting it may represent a distinct form of pro-inflammatory regulated necrosis. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  17. Protease-activated receptor-2 (PAR-2) in the rat gastric mucosa: immunolocalization and facilitation of pepsin/pepsinogen secretion

    Science.gov (United States)

    Kawao, Naoyuki; Sakaguchi, Yuriko; Tagome, Ai; Kuroda, Ryotaro; Nishida, Shozo; Irimajiri, Kiyohiro; Nishikawa, Hiroyuki; Kawai, Kenzo; Hollenberg, Morley D; Kawabata, Atsufumi

    2002-01-01

    Agonists of protease-activated receptor-2 (PAR-2) trigger neurally mediated mucus secretion accompanied by mucosal cytoprotection in the stomach. The present study immunolocalized PAR-2 in the rat gastric mucosa and examined if PAR-2 could modulate pepsin/pepsinogen secretion in rats. PAR-2-like immunoreactivity was abundant in the deep regions of gastric mucosa, especially in chief cells. The PAR-2 agonist SLIGRL-NH2, but not the control peptide LSIGRL-NH2, administered i.v. repeatedly at 0.3 – 1 μmol kg−1, four times in total, significantly facilitated gastric pepsin secretion, although a single dose produced no significant effect. The PAR-2-mediated gastric pepsin secretion was resistant to omeprazole, NG-nitro-L-arginine methyl ester (L-NAME) or atropine, and also to ablation of sensory neurons by capsaicin. Our study thus provides novel evidence that PAR-2 is localized in mucosal chief cells and facilitates gastric pepsin secretion in the rats, most probably by a direct mechanism. PMID:11877338

  18. Relationship between temperature optima and secreted protease activities of three Pythium species and pathogenicity toward plant and animal hosts.

    Science.gov (United States)

    Davis, Diana J; Lanter, Kelli; Makselan, Stephanie; Bonati, Christopher; Asbrock, Paige; Ravishankar, J P; Money, Nicholas P

    2006-01-01

    The in vitro physiological characteristics of three species of Pythium (oomycetes) that utilize different food sources were compared with their ecological activities: P. insidiosum is a pathogen of mammals (including humans), P. graminicola infects the roots of graminaceous hosts, and P. grandisporangium is an enigmatic water mold isolated from mangrove leaves and marine algae. P. insidiosum and P. graminicola showed peak growth rates at 37 degrees C before complete inhibition of growth at 40 degrees C; P. grandisporangium grew fastest at 22 degrees C. Differences between the invasive pressures exerted by the hyphae of these microorganisms were not considered significant in relation to the substrates colonized by these water molds. All three species showed substantial secreted protease activity, producing three or more serine proteases with weights ranging from 24-38 kDa. Fastest growth rates were supported when collagen was supplied as the sole carbon source, and none of the species were able to grow on purified plant cell wall polysaccharides. The growth and nutritional characteristics of P. graminicola and P. grandisporangium bear little obvious relationship to the ecological niches that they inhabit. This highlights the caution necessary in extrapolating from laboratory analyses to the natural environment, and points to the potential importance of ecological opportunity in determining the host range and food source of certain microorganisms.

  19. Inhibition of dengue virus replication by novel inhibitors of RNA-dependent RNA polymerase and protease activities.

    Science.gov (United States)

    Pelliccia, Sveva; Wu, Yu-Hsuan; Coluccia, Antonio; La Regina, Giuseppe; Tseng, Chin-Kai; Famiglini, Valeria; Masci, Domiziana; Hiscott, John; Lee, Jin-Ching; Silvestri, Romano

    2017-12-01

    Dengue virus (DENV) is the leading mosquito-transmitted viral infection in the world. With more than 390 million new infections annually, and up to 1 million clinical cases with severe disease manifestations, there continues to be a need to develop new antiviral agents against dengue infection. In addition, there is no approved anti-DENV agents for treating DENV-infected patients. In the present study, we identified new compounds with anti-DENV replication activity by targeting viral replication enzymes - NS5, RNA-dependent RNA polymerase (RdRp) and NS3 protease, using cell-based reporter assay. Subsequently, we performed an enzyme-based assay to clarify the action of these compounds against DENV RdRp or NS3 protease activity. Moreover, these compounds exhibited anti-DENV activity in vivo in the ICR-suckling DENV-infected mouse model. Combination drug treatment exhibited a synergistic inhibition of DENV replication. These results describe novel prototypical small anti-DENV molecules for further development through compound modification and provide potential antivirals for treating DENV infection and DENV-related diseases.

  20. Promoter methylation of protease-activated receptor (PAR2) is associated with severe clinical phenotypes of ulcerative colitis (UC).

    Science.gov (United States)

    Tahara, Tomomitsu; Shibata, Tomoyuki; Nakamura, Masakatsu; Yamashita, Hiromi; Yoshioka, Daisuke; Okubo, Masaaki; Maruyama, Naoko; Kamano, Toshiaki; Kamiya, Yoshio; Fujita, Hiroshi; Nakagawa, Yoshihito; Nagasaka, Mitsuo; Iwata, Masami; Takahama, Kazuya; Watanabe, Makoto; Nakano, Hiroshi; Hirata, Ichiro; Arisawa, Tomiyasu

    2009-06-01

    Tryptase acting at protease-activated receptor 2 (PAR2) contributes to the pathogenesis of Inflammatory bowel diseases (IBDs). DNA methylation has been shown to be an important mechanism in gene silencing. We attempted to clarify the relationship between the promoter methylation of PAR2 and ulcerative colitis (UC). 84 UC patients enrolled in the study. UC patients were classified by disease behavior, severity and extent of disease. For rectal inflammatory mucosal specimens from all the patients, and normal terminal ileum from 23 patients, promoter methylation of PAR2 gene was quantified by digital densitographic analysis following to methylation-specific polymerase chain reaction (MSP). The mean methylation levels of the PAR2 gene in all 84 subjects was 38.4 +/- 19.6%. Although mean methylation levels in rectal inflammatory mucosa, and paired normal terminal ileum did not vary, methylation levels of PAR2 gene was significantly higher in total colitis than rectal colitis (total colitis vs. rectal colitis; 42.9 +/- 19.6% vs. 34.5 +/- 18.9%, P = 0.046). The higher methylation levels were also associated with Steroid-dependent (P = 0.002) and refractory (P = 0.007) UC. Our data suggest that PAR2 methylation status in rectal mucosa correlates with more severe disease phenotypes of UC.

  1. Genome Plasticity and Polymorphisms in Critical Genes Correlate with Increased Virulence of Dutch Outbreak-Related Coxiella burnetii Strains

    Directory of Open Access Journals (Sweden)

    Runa Kuley

    2017-08-01

    Full Text Available Coxiella burnetii is an obligate intracellular bacterium and the etiological agent of Q fever. During 2007–2010 the largest Q fever outbreak ever reported occurred in The Netherlands. It is anticipated that strains from this outbreak demonstrated an increased zoonotic potential as more than 40,000 individuals were assumed to be infected. The acquisition of novel genetic factors by these C. burnetii outbreak strains, such as virulence-related genes, has frequently been proposed and discussed, but is not proved yet. In the present study, the whole genome sequence of several Dutch strains (CbNL01 and CbNL12 genotypes, a few additionally selected strains from different geographical locations and publicly available genome sequences were used for a comparative bioinformatics approach. The study focuses on the identification of specific genetic differences in the outbreak related CbNL01 strains compared to other C. burnetii strains. In this approach we investigated the phylogenetic relationship and genomic aspects of virulence and host-specificity. Phylogenetic clustering of whole genome sequences showed a genotype-specific clustering that correlated with the clustering observed using Multiple Locus Variable-number Tandem Repeat Analysis (MLVA. Ortholog analysis on predicted genes and single nucleotide polymorphism (SNP analysis of complete genome sequences demonstrated the presence of genotype-specific gene contents and SNP variations in C. burnetii strains. It also demonstrated that the currently used MLVA genotyping methods are highly discriminatory for the investigated outbreak strains. In the fully reconstructed genome sequence of the Dutch outbreak NL3262 strain of the CbNL01 genotype, a relatively large number of transposon-linked genes were identified as compared to the other published complete genome sequences of C. burnetii. Additionally, large numbers of SNPs in its membrane proteins and predicted virulence-associated genes were identified

  2. Strain differences in intermale aggression and possible factors regulating increased aggression in Japanese quail.

    Science.gov (United States)

    Maekawa, Fumihiko; Nagino, Koki; Yang, Jiaxin; Htike, Nang T T; Tsukahara, Shinji; Ubuka, Takayoshi; Tsutsui, Kazuyoshi; Kawashima, Takaharu

    2018-01-15

    The National Institute for Environmental Studies (NIES) of Japan established a strain of Japanese quail (Coturnix japonica) known as NIES-L by rotation breeding in a closed colony for over 35years; accordingly, the strain has highly inbred-like characteristics. Another strain called NIES-Brn has been maintained by randomized breeding in a closed colony to produce outbred-like characteristics. The current study aimed to characterize intermale aggressive behaviors in both strains and to identify possible factors regulating higher aggression in the hypothalamus, such as sex hormone and neuropeptide expression. Both strains displayed a common set of intermale aggressive behaviors that included pecking, grabbing, mounting, and cloacal contact behavior, although NIES-Brn quail showed significantly more grabbing, mounting, and cloacal contact behavior than did NIES-L quail. We examined sex hormone levels in the blood and diencephalon in both strains. Testosterone concentrations were significantly higher in the blood and diencephalon of NIES-Brn quail compared to NIES-L quail. We next examined gene expression in the hypothalamus of both strains using an Agilent gene expression microarray and real-time RT-PCR and found that gene expression of mesotocin (an oxytocin homologue) was significantly higher in the hypothalamus of NIES-Brn quail compared to NIES-L quail. Immunohistochemistry of the hypothalamus revealed that numbers of large cells (cell area>500μm 2 ) expressing mesotocin were significantly higher in the NIES-Brn strain compared to the NIES-L strain. Taken together, our findings suggest that higher testosterone and mesotocin levels in the hypothalamus may be responsible for higher aggression in the NIES-Brn quail strain. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Salicylic acid induced cysteine protease activity during programmed cell death in tomato plants.

    Science.gov (United States)

    Kovács, Judit; Poór, Péter; Szepesi, Ágnes; Tari, Irma

    2016-06-01

    The hypersensitive response (HR), a type of programmed cell death (PCD) during biotic stress is mediated by salicylic acid (SA). The aim of this work was to reveal the role of proteolysis and cysteine proteases in the execution of PCD in response of SA. Tomato plants were treated with sublethal (0.1 mM) and lethal (1 mM) SA concentrations through the root system. Treatment with 1 mM SA increased the electrolyte leakage and proteolytic activity and reduced the total protein content of roots after 6 h, while the proteolytic activity did not change in the leaves and in plants exposed to 0.1 mM SA. The expression of the papain-type cysteine protease SlCYP1, the vacuolar processing enzyme SlVPE1 and the tomato metacaspase SlMCA1 was induced within the first three hours in the leaves and after 0.5 h in the roots in the presence of 1 mM SA but the transcript levels did not increase significantly at sublethal SA. The Bax inhibitor-1 (SlBI-1), an antiapoptotic gene was over-expressed in the roots after SA treatments and it proved to be transient in the presence of sublethal SA. Protease inhibitors, SlPI2 and SlLTC were upregulated in the roots by sublethal SA but their expression remained low at 1 mM SA concentration. It is concluded that in contrast to leaves the SA-induced PCD is associated with increased proteolytic activity in the root tissues resulting from a fast up-regulation of specific cysteine proteases and down-regulation of protease inhibitors.

  4. Host Plants Indirectly Influence Plant Virus Transmission by Altering Gut Cysteine Protease Activity of Aphid Vectors*

    Science.gov (United States)

    Pinheiro, Patricia V.; Ghanim, Murad; Rebelo, Ana Rita; Santos, Rogerio S.; Orsburn, Benjamin C.; Gray, Stewart

    2017-01-01

    The green peach aphid, Myzus persicae, is a vector of the Potato leafroll virus (PLRV, Luteoviridae), transmitted exclusively by aphids in a circulative manner. PLRV transmission efficiency was significantly reduced when a clonal lineage of M. persicae was reared on turnip as compared with the weed physalis, and this was a transient effect caused by a host-switch response. A trend of higher PLRV titer in physalis-reared aphids as compared with turnip-reared aphids was observed at 24 h and 72 h after virus acquisition. The major difference in the proteomes of these aphids was the up-regulation of predicted lysosomal enzymes, in particular the cysteine protease cathepsin B (cathB), in aphids reared on turnip. The aphid midgut is the site of PLRV acquisition, and cathB and PLRV localization were starkly different in midguts of the aphids reared on the two host plants. In viruliferous aphids that were reared on turnip, there was near complete colocalization of cathB and PLRV at the cell membranes, which was not observed in physalis-reared aphids. Chemical inhibition of cathB restored the ability of aphids reared on turnip to transmit PLRV in a dose-dependent manner, showing that the increased activity of cathB and other cysteine proteases at the cell membrane indirectly decreased virus transmission by aphids. Understanding how the host plant influences virus transmission by aphids is critical for growers to manage the spread of virus among field crops. PMID:27932519

  5. Effect of a novel quaternary ammonium silane on dentin protease activities.

    Science.gov (United States)

    Umer, D; Yiu, C K Y; Burrow, M F; Niu, L-N; Tay, F R

    2017-03-01

    Demineralized dentin collagen release C-terminal cross-linked telopeptide (ICTP) and C-terminal peptide (CTX) during degradation. The present study evaluated the effects of dentin pre-treatment with K21, a quaternary ammonium silane (QAS), on matrix metalloproteinase (MMP) and cathepsin K-mediated collagen degradation. Dentin beams were demineralized with 10% H 3 PO 4 for 24h. After baseline dry mass measurements, the beams were divided into 5 groups (N=10) according to protease inhibitors. The beams were pre-treated for 2min with 2% chlorhexidine (CHX), 2%, 5% or 10% QAS; no pre-treatment was performed for the control group. The beams were subsequently incubated in calcium- and zinc-containing medium for 3, 7 or 14days, after which changes in dry mass were measured and incubation media were examined for ICTP and CTX release. The MMP-2 and cathepsin K activities in QAS-treated dentin powder were also quantified using ELISA. The two factors (disinfectants and time) had a significant effect on dry mass loss, ICTP and CTX release (psilane increases the resistance of dentin collagen to degradation by inhibiting endogenous matrix metalloproteinases and cysteine cathepsins. The quaternary ammonium silane cavity disinfectant is promising for use as a protease inhibitor to improve durability of resin-dentin bonds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Defining a new diagnostic assessment parameter for wound care: Elevated protease activity, an indicator of nonhealing, for targeted protease-modulating treatment.

    Science.gov (United States)

    Serena, Thomas E; Cullen, Breda M; Bayliff, Simon W; Gibson, Molly C; Carter, Marissa J; Chen, Lingyun; Yaakov, Raphael A; Samies, John; Sabo, Matthew; DeMarco, Daniel; Le, Namchi; Galbraith, James

    2016-05-01

    It is widely accepted that elevated protease activity (EPA) in chronic wounds impedes healing. However, little progress has occurred in quantifying the level of protease activity that is detrimental for healing. The aim of this study was to determine the relationship between inflammatory protease activity and wound healing status, and to establish the level of EPA above which human neutrophil-derived elastase (HNE) and matrix metalloproteases (MMP) activities correlate with nonhealing wounds. Chronic wound swab samples (n = 290) were collected from four wound centers across the USA to measure HNE and MMP activity. Healing status was determined according to percentage reduction in wound area over the previous 2-4 weeks; this was available for 211 wounds. Association between protease activity and nonhealing wounds was determined by receiver operating characteristic analysis (ROC), a statistical technique used for visualizing and analyzing the performance of diagnostic tests. ROC analysis showed that area under the curve (AUC) for HNE were 0.69 for all wounds and 0.78 for wounds with the most reliable wound trajectory information, respectively. For MMP, the corresponding AUC values were 0.70 and 0.82. Analysis suggested that chronic wounds having values of HNE >5 and/or MMP ≥13, should be considered wound healing impaired. EPA is indicative of nonhealing wounds. Use of a diagnostic test to detect EPA in clinical practice could enable clinicians to identify wounds that are nonhealing, thus enabling targeted treatment with protease modulating therapies. © 2016 by the Wound Healing Society.

  7. Host Plants Indirectly Influence Plant Virus Transmission by Altering Gut Cysteine Protease Activity of Aphid Vectors.

    Science.gov (United States)

    Pinheiro, Patricia V; Ghanim, Murad; Alexander, Mariko; Rebelo, Ana Rita; Santos, Rogerio S; Orsburn, Benjamin C; Gray, Stewart; Cilia, Michelle

    2017-04-01

    The green peach aphid, Myzus persicae , is a vector of the Potato leafroll virus (PLRV, Luteoviridae), transmitted exclusively by aphids in a circulative manner. PLRV transmission efficiency was significantly reduced when a clonal lineage of M. persicae was reared on turnip as compared with the weed physalis, and this was a transient effect caused by a host-switch response. A trend of higher PLRV titer in physalis-reared aphids as compared with turnip-reared aphids was observed at 24 h and 72 h after virus acquisition. The major difference in the proteomes of these aphids was the up-regulation of predicted lysosomal enzymes, in particular the cysteine protease cathepsin B (cathB), in aphids reared on turnip. The aphid midgut is the site of PLRV acquisition, and cathB and PLRV localization were starkly different in midguts of the aphids reared on the two host plants. In viruliferous aphids that were reared on turnip, there was near complete colocalization of cathB and PLRV at the cell membranes, which was not observed in physalis-reared aphids. Chemical inhibition of cathB restored the ability of aphids reared on turnip to transmit PLRV in a dose-dependent manner, showing that the increased activity of cathB and other cysteine proteases at the cell membrane indirectly decreased virus transmission by aphids. Understanding how the host plant influences virus transmission by aphids is critical for growers to manage the spread of virus among field crops. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Protease activity of the API2-MALT1 fusion oncoprotein in MALT lymphoma development and treatment.

    Science.gov (United States)

    Rosebeck, Shaun; Lucas, Peter C; McAllister-Lucas, Linda M

    2011-05-01

    Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a prototypical cancer that occurs in the setting of chronic inflammation and an important model for understanding how deregulated NF-κB transcriptional activity contributes to malignancy. Most gastric MALT lymphomas require ongoing antigenic stimulation for continued tumor growth, and Stage I disease is usually cured by eradicating the causative microorganism, Helicobacter pylori, with antibiotics. However, in a subset of MALT lymphomas, chromosomal translocations are acquired that render the lymphoma antigen-independent. The recurrent translocation t(11;18)(q21;q21) is associated with failure to respond to antibiotic therapy and increased rate of dissemination. This translocation creates the API2-MALT1 fusion oncoprotein, which comprises the amino terminus of inhibitor of apoptosis 2 (API2 or cIAP2) fused to the carboxy terminus of MALT1. A common characteristic of chromosomal translocations in MALT lymphoma, including t(11;18), is that genes involved in the regulation of the NF-κB transcription factor are targeted by the translocations, and these genetic perturbations thereby result in deregulated, constitutive NF-κB stimulation. In the last decade, great insights into the roles of API2 and MALT1 in NF-κB signaling have been made. For example, recent pivotal studies have uncovered the long sought-after proteolytic activity of MALT1 and have demonstrated its critical involvement in the survival of certain lymphomas. Here, we review the current understanding of the role of MALT1 in normal lymphocyte function and lymphomagenesis. We then highlight our recent work that has revealed an intriguing link between the proteolytic activity of the API2-MALT1 fusion and its ability to influence lymphomagenesis by cleaving a key NF-κB regulatory protein, NF-κB-inducing kinase.

  9. Profiling gene expression induced by protease-activated receptor 2 (PAR2 activation in human kidney cells.

    Directory of Open Access Journals (Sweden)

    Jacky Y Suen

    Full Text Available Protease-Activated Receptor-2 (PAR2 has been implicated through genetic knockout mice with cytokine regulation and arthritis development. Many studies have associated PAR2 with inflammatory conditions (arthritis, airways inflammation, IBD and key events in tumor progression (angiogenesis, metastasis, but they have relied heavily on the use of single agonists to identify physiological roles for PAR2. However such probes are now known not to be highly selective for PAR2, and thus precisely what PAR2 does and what mechanisms of downstream regulation are truly affected remain obscure. Effects of PAR2 activation on gene expression in Human Embryonic Kidney cells (HEK293, a commonly studied cell line in PAR2 research, were investigated here by comparing 19,000 human genes for intersecting up- or down-regulation by both trypsin (an endogenous protease that activates PAR2 and a PAR2 activating hexapeptide (2f-LIGRLO-NH(2. Among 2,500 human genes regulated similarly by both agonists, there were clear associations between PAR2 activation and cellular metabolism (1,000 genes, the cell cycle, the MAPK pathway, HDAC and sirtuin enzymes, inflammatory cytokines, and anti-complement function. PAR-2 activation up-regulated four genes more than 5 fold (DUSP6, WWOX, AREG, SERPINB2 and down-regulated another six genes more than 3 fold (TXNIP, RARG, ITGB4, CTSD, MSC and TM4SF15. Both PAR2 and PAR1 activation resulted in up-regulated expression of several genes (CD44, FOSL1, TNFRSF12A, RAB3A, COPEB, CORO1C, THBS1, SDC4 known to be important in cancer. This is the first widespread profiling of specific activation of PAR2 and provides a valuable platform for better understanding key mechanistic roles of PAR2 in human physiology. Results clearly support the development of both antagonists and agonists of human PAR2 as potential disease modifying therapeutic agents.

  10. Protease-activated receptor 1 and 2 contribute to angiotensin II-induced activation of adventitial fibroblasts from rat aorta

    International Nuclear Information System (INIS)

    He, Rui-Qing; Tang, Xiao-Feng; Zhang, Bao-Li; Li, Xiao-Dong; Hong, Mo-Na; Chen, Qi-Zhi; Han, Wei-Qing; Gao, Ping-Jin

    2016-01-01

    Adventitial fibroblasts (AFs) can be activated by angiotensin II (Ang II) and exert pro-fibrotic and pro-inflammatory effects in vascular remodeling. Protease-activated receptor (PAR) 1 and 2 play a significant role in fibrogenic and inflammatory diseases. The present study hypothesized that PAR1 and PAR2 are involved in Ang II-induced AF activation and contribute to adventitial remodeling. We found that direct activation of PAR1 and PAR2 with PAR1-AP and PAR2-AP led to AF activation, including proliferation and differentiation of AFs, extracellular matrix synthesis, as well as production of pro-fibrotic cytokine TGF-β and pro-inflammatory cytokines IL-6 and MCP-1. Furthermore, PAR1 and PAR2 mediated Ang II-induced AF activation, since both PAR1 and PAR2 antagonists inhibited Ang II-induced proliferation, migration, differentiation, extracellular matrix synthesis and production of pro-fibrotic and pro-inflammatory cytokines in AFs. Finally, mechanistic study showed that Ang II, via Ang II type I receptor (AT1R), upregulated both PAR1 and PAR2 expression, and transactivated PAR1 and PAR2, as denoted by internalization of both proteins. In conclusion, our results suggest that PAR1 and PAR2 play a critical role in Ang II-induced AF activation, and this may contribute to adventitia-related pathological changes. - Highlights: • Direct activation of PAR1 and PAR2 led to adventitial fibroblast (AF) activation. • PAR1 and PAR2 antagonists attenuated Ang II-induced AF activation. • Ang II induced the upregulation and transactivation of PAR1/PAR2 in AFs.

  11. Protease-activated receptor 1 and 2 contribute to angiotensin II-induced activation of adventitial fibroblasts from rat aorta

    Energy Technology Data Exchange (ETDEWEB)

    He, Rui-Qing; Tang, Xiao-Feng; Zhang, Bao-Li [State Key Laboratory of Medical Genetics, Shanghai Key Laboratory of Hypertension and Department of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (China); Shanghai Institute of Hypertension, Shanghai (China); Li, Xiao-Dong [State Key Laboratory of Medical Genetics, Shanghai Key Laboratory of Hypertension and Department of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (China); Laboratory of Vascular Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Shanghai Institute of Hypertension, Shanghai (China); Hong, Mo-Na [State Key Laboratory of Medical Genetics, Shanghai Key Laboratory of Hypertension and Department of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (China); Shanghai Institute of Hypertension, Shanghai (China); Chen, Qi-Zhi [Shanghai Institute of Hypertension, Shanghai (China); Han, Wei-Qing, E-mail: whan020@gmail.com [State Key Laboratory of Medical Genetics, Shanghai Key Laboratory of Hypertension and Department of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (China); Laboratory of Vascular Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Shanghai Institute of Hypertension, Shanghai (China); Gao, Ping-Jin, E-mail: gaopingjin@sibs.ac.cn [State Key Laboratory of Medical Genetics, Shanghai Key Laboratory of Hypertension and Department of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (China); Laboratory of Vascular Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Shanghai Institute of Hypertension, Shanghai (China)

    2016-04-29

    Adventitial fibroblasts (AFs) can be activated by angiotensin II (Ang II) and exert pro-fibrotic and pro-inflammatory effects in vascular remodeling. Protease-activated receptor (PAR) 1 and 2 play a significant role in fibrogenic and inflammatory diseases. The present study hypothesized that PAR1 and PAR2 are involved in Ang II-induced AF activation and contribute to adventitial remodeling. We found that direct activation of PAR1 and PAR2 with PAR1-AP and PAR2-AP led to AF activation, including proliferation and differentiation of AFs, extracellular matrix synthesis, as well as production of pro-fibrotic cytokine TGF-β and pro-inflammatory cytokines IL-6 and MCP-1. Furthermore, PAR1 and PAR2 mediated Ang II-induced AF activation, since both PAR1 and PAR2 antagonists inhibited Ang II-induced proliferation, migration, differentiation, extracellular matrix synthesis and production of pro-fibrotic and pro-inflammatory cytokines in AFs. Finally, mechanistic study showed that Ang II, via Ang II type I receptor (AT1R), upregulated both PAR1 and PAR2 expression, and transactivated PAR1 and PAR2, as denoted by internalization of both proteins. In conclusion, our results suggest that PAR1 and PAR2 play a critical role in Ang II-induced AF activation, and this may contribute to adventitia-related pathological changes. - Highlights: • Direct activation of PAR1 and PAR2 led to adventitial fibroblast (AF) activation. • PAR1 and PAR2 antagonists attenuated Ang II-induced AF activation. • Ang II induced the upregulation and transactivation of PAR1/PAR2 in AFs.

  12. The threonine protease activity of testes-specific protease 50 (TSP50 is essential for its function in cell proliferation.

    Directory of Open Access Journals (Sweden)

    Yu-Yin Li

    Full Text Available BACKGROUND: Testes-specific protease 50 (TSP50, a newly discovered threonine enzyme, has similar amino acid sequences and enzymatic structures to those of many serine proteases. It may be an oncogene. TSP50 is up-regulated in breast cancer epithelial cells, and ectopic expression of TSP50 in TSP50-deficient Chinese hamster ovary (CHO cells has been found to promote cell proliferation. However, the mechanisms by which TSP50 exerts its growth-promoting effects are not yet fully understood. METHODOLOGY/PRINCIPAL FINDINGS: To delineate whether the threonine protease activity of TSP50 is essential to its function in cell proliferation, we constructed and characterized a mutant TSP50, called TSP50 T310A, which was identified as a protease-dead mutant of TSP50. By a series of proliferation analyses, colony formation assays and apoptosis analyses, we showed that T310A mutation significantly depresses TSP50-induced cell proliferation in vitro. Next, the CHO stable cell line expressing either wild-type or T310A mutant TSP50 was injected subcutaneously into nude mice. We found that the T310A mutation could abolish the tumorigenicity of TSP50 in vivo. A mechanism investigation revealed that the T310A mutation prevented interaction between TSP50 and the NF-κBIκBα complex, which is necessary for TSP50 to perform its function in cell proliferation. CONCLUSION: Our data highlight the importance of threonine 310, the most critical protease catalytic site in TSP50, to TSP50-induced cell proliferation and tumor formation.

  13. Alternaria Fungus Induces the Production of GM-CSF, Interleukin-6 and Interleukin-8 and Calcium Signaling in Human Airway Epithelium through Protease-Activated Receptor 2

    Science.gov (United States)

    Matsuwaki, Yoshinori; Wada, Kota; White, Thomas; Moriyama, Hiroshi; Kita, Hirohito

    2012-01-01

    Rationale Recent studies suggest that host immune responses to environmental fungi may play an important role in the development of allergic diseases, such as human asthma. Epithelium is considered an active participant in allergic inflammation. We previously reported that aspartate protease from Alternaria induces the activation and degranulation of human eosinophils that are mediated through protease-activated receptor 2 (PAR-2). However, our current knowledge on the innate immune responses of epithelium to environmental fungi is very limited. We investigated the responses of epithelium to fungi and the mechanisms of these responses. Methods Human airway epithelial cell line BEAS-2B and Calu-3 (both from American Type Culture Collection) were incubated with PAR-2 peptides and extracts of various fungi. The cellular responses, including GM-CSF, interleukin (IL)-6, IL-8, eotaxin, eotaxin-2 and RANTES production as well as increases in intracellular calcium concentration ([Ca2+]i), were examined. To characterize the proteases involved in these responses, protease inhibitors such as pepstatin A and alkalo-thermophilic Bacillus inhibitor (ATBI), HIV protease inhibitors and 4-amidinophenylmethanesulfonyl fluoride hydrochloride were used. To investigate the role of PAR-2, PAR-2-agonistic and PAR-2-antagonistic peptides were used. Results PAR-2-activating peptide, but not the control peptide, induced GM-CSF, IL-6 and IL-8 production; these cellular responses were accompanied by a quick and marked increase in [Ca2+]i. Among 7 common environmental fungi, only Alternaria induced GM-CSF, IL-6 and IL-8 production and increased [Ca2+]i response. Both cytokine production and increased [Ca2+]i were significantly inhibited by PAR-2 antagonist peptide and by aspartate protease inhibitors (pepstatin A, ritonavir, nelfinavir and ATBI), but not by the PAR-2 control peptide or by other protease inhibitors. Conclusions Aspartate proteases from Alternaria induce cytokine production and

  14. Non-Conventional Yeast Strains Increase the Aroma Complexity of Bread

    Science.gov (United States)

    Rezaei, Mohammad Naser; Steensels, Jan; Courtin, Christophe M.; Verstrepen, Kevin J.

    2016-01-01

    Saccharomyces cerevisiae is routinely used yeast in food fermentations because it combines several key traits, including fermentation efficiency and production of desirable flavors. However, the dominance of S. cerevisiae in industrial fermentations limits the diversity in the aroma profiles of the end products. Hence, there is a growing interest in non-conventional yeast strains that can help generate the diversity and complexity desired in today’s diversified and consumer-driven markets. Here, we selected a set of non-conventional yeast strains to examine their potential for bread fermentation. Here, we tested ten non-conventional yeasts for bread fermentation, including two Saccharomyces species that are not currently used in bread making and 8 non-Saccharomyces strains. The results show that Torulaspora delbrueckii and Saccharomyces bayanus combine satisfactory dough fermentation with an interesting flavor profile. Sensory analysis and HS-SPME-GC-MS analysis confirmed that these strains produce aroma profiles that are very different from that produced by a commercial bakery strain. Moreover, bread produced with these yeasts was preferred by a majority of a trained sensory panel. These results demonstrate the potential of T. delbrueckii and S. bayanus as alternative yeasts for bread dough leavening, and provide a general experimental framework for the evaluation of more yeasts and bacteria. PMID:27776154

  15. Non-Conventional Yeast Strains Increase the Aroma Complexity of Bread.

    Directory of Open Access Journals (Sweden)

    Elham Aslankoohi

    Full Text Available Saccharomyces cerevisiae is routinely used yeast in food fermentations because it combines several key traits, including fermentation efficiency and production of desirable flavors. However, the dominance of S. cerevisiae in industrial fermentations limits the diversity in the aroma profiles of the end products. Hence, there is a growing interest in non-conventional yeast strains that can help generate the diversity and complexity desired in today's diversified and consumer-driven markets. Here, we selected a set of non-conventional yeast strains to examine their potential for bread fermentation. Here, we tested ten non-conventional yeasts for bread fermentation, including two Saccharomyces species that are not currently used in bread making and 8 non-Saccharomyces strains. The results show that Torulaspora delbrueckii and Saccharomyces bayanus combine satisfactory dough fermentation with an interesting flavor profile. Sensory analysis and HS-SPME-GC-MS analysis confirmed that these strains produce aroma profiles that are very different from that produced by a commercial bakery strain. Moreover, bread produced with these yeasts was preferred by a majority of a trained sensory panel. These results demonstrate the potential of T. delbrueckii and S. bayanus as alternative yeasts for bread dough leavening, and provide a general experimental framework for the evaluation of more yeasts and bacteria.

  16. Protease-activated receptor-2 promotes kidney tubular epithelial inflammation by inhibiting autophagy via the PI3K/Akt/mTOR signalling pathway.

    Science.gov (United States)

    Du, Chunyang; Zhang, Tao; Xiao, Xia; Shi, Yonghong; Duan, Huijun; Ren, Yunzhuo

    2017-08-02

    Protease-activated receptor-2 (PAR2), which belongs to a specific class of the G-protein-coupled receptors, is central to several inflammation processes. However, the precise molecular mechanism involved remains undefined. Autophagy has been previously shown to affect inflammation. In the present study, we examine the effect of PAR2 on kidney tubular epithelial autophagy and on autophagy-related inflammation and reveal the underlying mechanism involved. Autophagic activity and levels of autophagic marker LC3 were examined in human kidney tubular epithelial cells with PAR2 knockdown or overexpression. We administered the mammalian target of rapamycin (mTOR) inhibitor (rapamycin) or activator (MHY1485) to investigate the function of the phosphoinositide 3-kinase (PI3K)/Akt/mTOR pathway. We also used transforming growth factor-β1 (TGF-β1)-induced HK-2 cell inflammation models to investigate the role of PAR2-associated autophagy in kidney tubular epithelial inflammation. PAR2 antagonist and rapamycin were administered to mice after unilateral ureteral obstruction to detect the correlations between PAR2, autophagy, and inflammation. Our results show that PAR2 overexpression in HK-2 cells led to a greater reduction in autophagy via the PI3K/Akt/mTOR pathway activation and induces autophagy-related inflammation. Meanwhile, a knockdown of PAR2 via PAR2 RNAi transfection greatly increased autophagy and alleviated autophagy-associated inflammation. In unilateral ureteral obstruction (UUO) kidneys, PAR2 antagonist treatment greatly attenuated renal inflammation and interstitial injury by enhancing autophagy. Moreover, inhibition of mTOR, rapa, markedly increased autophagy and inhibited the UUO-induced inflammation. We conclude that PAR2 induces kidney tubular epithelial inflammation by inhibiting autophagy via the PI3K/Akt/mTOR signalling pathway. Our results are suggestive that PAR2 inhibition may play a role in the treatment of diseases with increased inflammatory

  17. Anti-inflammatory Lactobacillus rhamnosus CNCM I-3690 strain protects against oxidative stress and increases lifespan in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Gianfranco Grompone

    Full Text Available Numerous studies have shown that resistance to oxidative stress is crucial to stay healthy and to reduce the adverse effects of aging. Accordingly, nutritional interventions using antioxidant food-grade compounds or food products are currently an interesting option to help improve health and quality of life in the elderly. Live lactic acid bacteria (LAB administered in food, such as probiotics, may be good antioxidant candidates. Nevertheless, information about LAB-induced oxidative stress protection is scarce. To identify and characterize new potential antioxidant probiotic strains, we have developed a new functional screening method using the nematode Caenorhabditis elegans as host. C. elegans were fed on different LAB strains (78 in total and nematode viability was assessed after oxidative stress (3 mM and 5 mM H(2O(2. One strain, identified as Lactobacillus rhamnosus CNCM I-3690, protected worms by increasing their viability by 30% and, also, increased average worm lifespan by 20%. Moreover, transcriptomic analysis of C. elegans fed with this strain showed that increased lifespan is correlated with differential expression of the DAF-16/insulin-like pathway, which is highly conserved in humans. This strain also had a clear anti-inflammatory profile when co-cultured with HT-29 cells, stimulated by pro-inflammatory cytokines, and co-culture systems with HT-29 cells and DC in the presence of LPS. Finally, this Lactobacillus strain reduced inflammation in a murine model of colitis. This work suggests that C. elegans is a fast, predictive and convenient screening tool to identify new potential antioxidant probiotic strains for subsequent use in humans.

  18. Increased transmission of Mycobacterium tuberculosis Beijing genotype strains associated with resistance to streptomycin: a population-based study.

    Science.gov (United States)

    Buu, Tran N; van Soolingen, Dick; Huyen, Mai N T; Lan, Nguyen T N; Quy, Hoang T; Tiemersma, Edine W; Kremer, Kristin; Borgdorff, Martien W; Cobelens, Frank G J

    2012-01-01

    Studies have shown that the Mycobacterium tuberculosis Beijing genotype is an emerging pathogen that is frequently associated with drug resistance. This suggests that drug resistant Beijing strains have a relatively high transmission fitness compared to other drug-resistant strains. We studied the relative transmission fitness of the Beijing genotype in relation to anti-tuberculosis drug resistance in a population-based study of smear-positive tuberculosis patients prospectively recruited and studied over a 4-year period in rural Vietnam. Transmission fitness was analyzed by clustering of cases on basis of three DNA typing methods. Of 2531 included patients, 2207 (87%) were eligible for analysis of whom 936 (42%) were in a DNA fingerprint cluster. The clustering rate varied by genotype with 292/786 (37%) for the Beijing genotype, 527/802 (67%) for the East-African Indian (EAI) genotype, and 117/619 (19%) for other genotypes. Clustering was associated with the EAI compared to the Beijing genotype (adjusted odds ratio (OR(adj)) 3.4: 95% CI 2.8-4.4). Patients infected with streptomycin-resistant strains were less frequently clustered than patients infected with streptomycin-susceptible strains when these were of the EAI genotype (OR(adj) 0.6, 95% CI 0.4-0.9), while this pattern was reversed for strains of the Beijing genotype (OR(adj) 1.3, 95% CI 1.0-1.8, p for difference 0.002). The strong association between Beijing and MDR-TB (OR(adj) 7.2; 95% CI 4.2-12.3) existed only if streptomycin resistance was present. Beijing genotype strains showed less overall transmissibility than EAI strains, but when comparisons were made within genotypes, Beijing strains showed increased transmission fitness when streptomycin-resistant, while the reverse was observed for EAI strains. The association between MDR-TB and Beijing genotype in this population was strongly dependent on resistance to streptomycin. Streptomycin resistance may provide Beijing strains with a fitness advantage

  19. Increased cytotoxicity and streptolysin O activity in group G streptococcal strains causing invasive tissue infections

    DEFF Research Database (Denmark)

    Siemens, Nikolai; Kittang, Bård R; Chakrakodi, Bhavya

    2015-01-01

    Streptococcus dysgalactiae subsp. equisimilis (SDSE) has emerged as an important cause of severe skin and soft tissue infections, but little is known of the pathogenic mechanisms underlying tissue pathology. Patient samples and a collection of invasive and non-invasive group G SDSE strains (n = 69...

  20. Rational Design of Cyclodextrin Glycosyltransferase from Bacillus circulans Strain 251 to Increase α-Cyclodextrin Production

    NARCIS (Netherlands)

    Veen, Bart A. van der; Uitdehaag, Joost C.M.; Penninga, Dirk; Alebeek, Gert-Jan W.M. van; Smith, Loraine M.; Dijkstra, Bauke W.; Dijkhuizen, Lubbert

    2000-01-01

    Cyclodextrin glycosyltransferases (CGTase) (EC 2.4.1.19) are extracellular bacterial enzymes that generate cyclodextrins from starch. All known CGTases produce mixtures of α, β, and γ-cyclodextrins. A maltononaose inhibitor bound to the active site of the CGTase from Bacillus circulans strain 251

  1. Increased heterologous production of the antitumoral polyketide mithramycin A by engineered Streptomyces lividans TK24 strains.

    Science.gov (United States)

    Novakova, Renata; Núñez, Luz Elena; Homerova, Dagmar; Knirschova, Renata; Feckova, Lubomira; Rezuchova, Bronislava; Sevcikova, Beatrica; Menéndez, Nuria; Morís, Francisco; Cortés, Jesús; Kormanec, Jan

    2018-01-01

    Mithramycin A is an antitumor compound used for treatment of several types of cancer including chronic and acute myeloid leukemia, testicular carcinoma, hypercalcemia and Paget's disease. Selective modifications of this molecule by combinatorial biosynthesis and biocatalysis opened the possibility to produce mithramycin analogues with improved properties that are currently under preclinical development. The mithramycin A biosynthetic gene cluster from Streptomyces argillaceus ATCC12956 was cloned by transformation assisted recombination in Saccharomyces cerevisiae and heterologous expression in Streptomyces lividans TK24 was evaluated. Mithramycin A was efficiently produced by S. lividans TK24 under standard fermentation conditions. To improve the yield of heterologously produced mithramycin A, a collection of derivative strains of S. lividans TK24 were constructed by sequential deletion of known potentially interfering secondary metabolite gene clusters using a protocol based on the positive selection of double crossover events with blue pigment indigoidine-producing gene. Mithramycin A production was evaluated in these S. lividans strains and substantially improved mithramycin A production was observed depending on the deleted gene clusters. A collection of S. lividans strains suitable for heterologous expression of actinomycetes secondary metabolites were generated and efficient production of mithramycin A with yields close to 3 g/L, under the tested fermentation conditions was achieved using these optimized collection of strains.

  2. Mutant strains of Spirulina (Arthrospira) platensis to increase the efficiency of micro-ecological life support systems

    Science.gov (United States)

    Brown, Igor

    The European Micro-Ecological Life Support System Alternative (MELiSSA) is an advanced idea for organizing a bioregenerative system for long term space flights and extraterrestrial settlements (Hendrickx, De Wever et al., 2005). Despite the hostility of both lunar and Martian environments to unprotected life, it seems possible to cultivate photosynthetic bacteria using closed bioreactors illuminated and heated by solar energy. Such reactors might be employed in critical processes, e.g. air revitalization, foodcaloric and protein source, as well as an immunomodulators production. The MELiSSA team suggested cyanobacterium Spirulina as most appropriate agent to revitalize air and produce a simple "fast" food. This is right suggestion because Spirulina was recently shown to be an oxygenic organism with the highest level of O2 production per unit mass (Ananyev et al., 2005). Chemical composition of Spirulina includes proteins (55Aiming to make Spirulina cultivation in life support systems like MELiSSA more efficient, we selected Spirulina mutant strains with increased fraction of methionine in the biomass of this cyanobacterium and compared the effect of parental wild strain of Spirulina and its mutants on the tendency of such experimental illnesses as radiationinduced lesions and hemolythic anemia. Results: It was found that mutant strains 198B and 27G contain higher quantities of total protein, essential amino acids, c-phycocyanin, allophycocyanin and chlorophyll a than parental wild strain of S. platensis. The strain 198B is also characterized with increased content of carotenoids. Revealed biochemical peculiarities of mutant strains suggest that these strains can serve as an additional source of essential amino acids as well as phycobiliproteins and carotenoids for the astronauts. Feeding animals suffering from radiation-induced lesions, c-phycocyanin, extracted from strain 27G, led to a correction in deficient dehydrogenase activity and energy-rich phosphate levels

  3. Increasing cell biomass in Saccharomyces cerevisiae increases recombinant protein yield: the use of a respiratory strain as a microbial cell factory

    Directory of Open Access Journals (Sweden)

    Hedfalk Kristina

    2010-06-01

    Full Text Available Abstract Background Recombinant protein production is universally employed as a solution to obtain the milligram to gram quantities of a given protein required for applications as diverse as structural genomics and biopharmaceutical manufacture. Yeast is a well-established recombinant host cell for these purposes. In this study we wanted to investigate whether our respiratory Saccharomyces cerevisiae strain, TM6*, could be used to enhance the productivity of recombinant proteins over that obtained from corresponding wild type, respiro-fermentative strains when cultured under the same laboratory conditions. Results Here we demonstrate at least a doubling in productivity over wild-type strains for three recombinant membrane proteins and one recombinant soluble protein produced in TM6* cells. In all cases, this was attributed to the improved biomass properties of the strain. The yield profile across the growth curve was also more stable than in a wild-type strain, and was not further improved by lowering culture temperatures. This has the added benefit that improved yields can be attained rapidly at the yeast's optimal growth conditions. Importantly, improved productivity could not be reproduced in wild-type strains by culturing them under glucose fed-batch conditions: despite having achieved very similar biomass yields to those achieved by TM6* cultures, the total volumetric yields were not concomitantly increased. Furthermore, the productivity of TM6* was unaffected by growing cultures in the presence of ethanol. These findings support the unique properties of TM6* as a microbial cell factory. Conclusions The accumulation of biomass in yeast cell factories is not necessarily correlated with a proportional increase in the functional yield of the recombinant protein being produced. The respiratory S. cerevisiae strain reported here is therefore a useful addition to the matrix of production hosts currently available as its improved biomass

  4. Increased survival and proliferation of the epidemic strain Mycobacterium abscessus subsp. massiliense CRM0019 in alveolar epithelial cells.

    Science.gov (United States)

    Ribeiro, Giovanni Monteiro; Matsumoto, Cristianne Kayoko; Real, Fernando; Teixeira, Daniela; Duarte, Rafael Silva; Mortara, Renato Arruda; Leão, Sylvia Cardoso; de Souza Carvalho-Wodarz, Cristiane

    2017-09-13

    Outbreaks of infections caused by rapidly growing mycobacteria have been reported worldwide generally associated with medical procedures. Mycobacterium abscessus subsp. massiliense CRM0019 was obtained during an epidemic of postsurgical infections and was characterized by increased persistence in vivo. To better understand the successful survival strategies of this microorganism, we evaluated its infectivity and proliferation in macrophages (RAW and BMDM) and alveolar epithelial cells (A549). For that, we assessed the following parameters, for both M. abscessus CRM0019 as well as the reference strain M. abscessus ATCC 19977: internalization, intracellular survival for up 3 days, competence to subvert lysosome fusion and the intracellular survival after cell reinfection. CRM0019 and ATCC 19977 strains showed the same internalization rate (approximately 30% after 6 h infection), in both A549 and RAW cells. However, colony forming units data showed that CRM0019 survived better in A549 cells than the ATCC 19977 strain. Phagosomal characteristics of CRM0019 showed the bacteria inside tight phagosomes in A549 cells, contrasting to the loosely phagosomal membrane in macrophages. This observation holds for the ATCC 19977 strain in both cell types. The competence to subvert lysosome fusion was assessed by acidification and acquisition of lysosomal protein. For M. abscessus strains the phagosomes were acidified in all cell lines; nevertheless, the acquisition of lysosomal protein was reduced by CRM0019 compared to the ATCC 19977 strain, in A549 cells. Conversely, in macrophages, both M. abscessus strains were located in mature phagosomes, however without bacterial death. Once recovered from macrophages M. abscessus could establish a new intracellular infection. Nevertheless, only CRM0019 showed a higher growth rate in A549, increasing nearly 10-fold after 48 and 72 h. M. abscessus CRM0019 creates a protective and replicative niche in alveolar epithelial cells mainly by

  5. Hand immersion in cold water alleviating physiological strain and increasing tolerance to uncompensable heat stress.

    Science.gov (United States)

    Khomenok, Gennadi A; Hadid, Amir; Preiss-Bloom, Orahn; Yanovich, Ran; Erlich, Tomer; Ron-Tal, Osnat; Peled, Amir; Epstein, Yoram; Moran, Daniel S

    2008-09-01

    The current study examines the use of hand immersion in cold water to alleviate physiological strain caused by exercising in a hot climate while wearing NBC protective garments. Seventeen heat acclimated subjects wearing a semi-permeable NBC protective garment and a light bulletproof vest were exposed to a 125 min exercise-heat stress (35 degrees C, 50% RH; 5 km/h, 5% incline). The heat stress exposure routine included 5 min rest in the chamber followed by two 50:10 min work-rest cycles. During the control trial (CO), there was no intervention, whilst in the intervention condition the subjects immersed their hands and forearms in a 10 degrees C water bath (HI). The results demonstrated that hand immersion in cold water significantly reduced physiological strain. In the CO exposure during the first and second resting periods, the average rectal temperature (T (re)) practically did not decrease. With hand immersion, the mean (SD) T (re) decreased by 0.45 (0.05 degrees C) and 0.48 degrees C (0.06 degrees C) during the first and second rest periods respectively (P immersion in cold water for 10 min is an effective method for decreasing the physiological strain caused by exercising under heat stress while wearing NBC protective garments. The method is convenient, simple, and allows longer working periods in hot or contaminated areas with shorter resting periods.

  6. A multicopy phr-plasmid increases the ultraviolet resistance of a recA strain of Escherichia coli

    International Nuclear Information System (INIS)

    Yamamoto, K.; Satake, M.; Shinagawa, H.

    1984-01-01

    It has been previously reported that the ultraviolet sensitivity of recA strains of Escherichia coli in the dark is suppressed by a plasmid pKY1 which carries the phr gene, suggesting that this is due to a novel effect of photoreactivating enzyme (PRE) of E. coli in the dark. In this work, it is observed that an increase of UV-resistance by pKY1 in the dark is not apparent in strains with a mutation in either uvrA, uvrB, uvrC, lexA, recBC or recF. The sensitivity of recA lexA and recA recBC multiple mutants to UV is suppressed by the plasmid but that of recA uvrA, recA uvrB and recA uvrC is not. Host-cell reactivation of UV-irradiated lambda phage is slightly more efficient in the recA/pKY1 strain compared with the parental recA strain. On the other hand, the recA and recA/pKY1 strains do not differ significantly in the following properties: Hfr recombination, induction of lambda by UV, and mutagenesis. It is suggested that dark repair of PRE is correlated with its capacity of excision repair. (Auth.)

  7. Coseismic Strain Steps of the 2008 Wenchuan Earthquake Indicate EW Extension of Tibetan Plateau and Increased Hazard South to Epicenter

    Science.gov (United States)

    Fu, G.; Shen, X.; Tang, J.; Fukuda, Y.

    2008-12-01

    The 2008 Wenchuan earthquake (Ms8.0) occurred at the east edge of Tibetan Plateau. It is the biggest seismic disaster in China since the 1976 Tangshan earthquake. To determine the effects of the earthquake on the deformation field of Tibetan Plateau, we collect and analyze continuing strain data of three stations before and after the earthquake in Tibetan Plateau observed by capacitance-type bore-hole strainmeters (Chi, 1985). We collect strain data in NS, EW, NE-SW and NW-NS directions at each borehole. Then we deduce the co-seismic strain steps at time point 14:28 of May 12, 2008 (at this time point the earthquake occurred) with the data before and after the earthquake using the least squares method. Our observation shows that in Tibetan Plateau significant co-seismic strain steps are accompanied with the 2008 Wenchuan earthquake. Extension in EW direction is observed at interior and north Tibetan Plateau which indicates a rapid EW extension of the whole Plateau. Field investigation shows that the 2008 Wenchuan earthquake is a manifestation of eastward growth of the Tibetan Plateau (Dong et al., 2008). Eastwards growth of the Tibetan Plateau results naturally in the extension of the Plateau in EW direction. Our co-seismic strain observation agrees well with the conclusion from surface rupture investigation. The magnitude of co-seismic strain step equals to five times of average year extensional strain rate throughout the plateau interior. Shortening in SE- NW direction is observed at the east edge of the Plateau. As hints that the eastward extension of Tibetan Plateau is resisted by Sichuan rigid basin which increases the potential earthquake hazard around the observation station, manifests the declaration from co-seismic stress changes calculation (Persons et al., 2008). Our observed co-seismic strain steps are in total lager than theoretical calculations of dislocation theories which indicate that magnitude of the great earthquake should be bigger than 7.9. Due

  8. NEW STRAIN PRODUCERS OF BIOBUTANOL. III. METHODS OF INCREASED BUTANOL ACCUMULATION FROM BIOMASS OF SWITCHGRASS Panicum virgatum L.

    Directory of Open Access Journals (Sweden)

    Tigunova O. O.

    2015-08-01

    Full Text Available The aim of this work was to enlarge accumulation of butanol from switchgrass Panicum virgatum L. biomass using strains-producers obtained from grounds and silts of Kyiv lakes. The objects of the study were strains of C. acetobutylicum ІМВ B-7407 (IFBG C6H, Clostridium acetobutylicum IFBG C6H 5М and Clostridium tyrobutyricum IFBG C4B from the "Collections of microbial strains and lines of plants for food and agricultural biotechnology" of the Public Institution "Institute of Food Biotechnology and Genomics" of the National Academy of Sciences of Ukraine. Gas chromatography was used to determine the alcohol concentration at the stage of solvent synthesis. To determine the effect of butanol precursors during cultivation, butyric, lactic and acetic acids were used. Optimization of processing parameters, which was based on the needs of cultures, allowed us to increase the yield by 20 and 50% for the initial and mutant strain respectively. Using synthetic precursors (such as lactic, butyric and acetic acid during cultivation increased total concentration of butanol by 1.7 times. To optimize the process, a study was carried out using acetone- butyl grains. Using of acetone-butyl grains in concentrations up to 60% does not affect the synthesis of butanol by C. acetobutylicum IFBG C6H 5M. Increasing the concentration of grains led to decrease in accumulation of butanol. Almost double increase in accumulation of the target product (butanol was achieved using two-stage fermentation and/or precursors of synthesis. It was shown the possibility of using acetone-butyl grains in fermentation. As a result the mass fraction of the waste was reduced.

  9. Inclusion of periodontal ligament fibres in mandibular finite element models leads to an increase in alveolar bone strains.

    Directory of Open Access Journals (Sweden)

    Steven W McCormack

    Full Text Available Alveolar bone remodelling is vital for the success of dental implants and orthodontic treatments. However, the underlying biomechanical mechanisms, in particular the function of the periodontal ligament (PDL in bone loading and remodelling, are not well understood. The PDL is a soft fibrous connective tissue that joins the tooth root to the alveolar bone and plays a critical role in the transmission of loads from the tooth to the surrounding bone. However, due to its complex structure, small size and location within the tooth socket it is difficult to study in vivo. Finite element analysis (FEA is an ideal tool with which to investigate the role of the PDL, however inclusion of the PDL in FE models is complex and time consuming, therefore consideration must be given to how it is included. The aim of this study was to investigate the effects of including the PDL and its fibrous structure in mandibular finite element models. A high-resolution model of a human molar region was created from micro-computed tomography scans. This is the first time that the fibrous structure of the PDL has been included in a model with realistic tooth and bone geometry. The results show that omission of the PDL creates a more rigid model, reducing the strains observed in the mandibular corpus which are of interest when considering mandibular functional morphology. How the PDL is modelled also affects the strains. The inclusion of PDL fibres alters the strains in the mandibular bone, increasing the strains in the tooth socket compared to PDL modelled without fibres. As strains in the alveolar bone are thought to play a key role in bone remodelling during orthodontic tooth movement, future FE analyses aimed at improving our understanding and management of orthodontic treatment should include the fibrous structure of the PDL.

  10. Protease activated receptors (PARS) mediation in gyroxin biological activity; Mediacao dos receptores ativados por proteases (PARs) em atividades biologicas da giroxina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jose Alberto Alves da

    2009-07-01

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH{sub 2}, respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  11. In vitro inhibition of protease-activated receptors 1, 2 and 4 demonstrates that these receptors are not involved in an Acanthamoeba castellanii keratitis isolate-mediated disruption of the human brain microvascular endothelial cells.

    Science.gov (United States)

    Iqbal, Junaid; Naeem, Komal; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2014-11-01

    Granulomatous amoebic encephalitis is a rare but serious human disease leading almost always to death. The pathophysiology of amoebic encephalitis is better understood, while events leading to the constitution of brain infection are largely unknown. Traversal of the blood-brain barrier is a key step in amoebae invasion of the central nervous system and facilitated by amoebic extracellular proteases. By using specific inhibitors of protease-activated receptors 1, 2 and 4, here we studied the role of these host receptors in Acanthamoeba castellanii-mediated damage to human brain microvasculature endothelial cells (HBMEC), which constitute the blood-brain barrier. The primary HBMEC were incubated with A. castellanii-conditioned medium in the presence or absence of FR-171113 (selective inhibitor of protease-activated receptor 1), FSLLRY-NH2 (inhibitor of protease-activated receptor 2), and tcY-NH2 (inhibitor of protease-activated receptor 4). The HBMEC monolayer disruptions were assessed by microscopy using Eosin staining, while host cell cytotoxicity was determined by measuring the release of cytoplasmic lactate dehydrogenase. Zymographic assays were performed to determine the effects of inhibitors of protease-activated receptors on the extracellular proteolytic activities of A. castellanii. A. castellanii-conditioned medium produced severe HBMEC monolayer disruptions within 60 min. The selective inhibitors of protease-activated receptors tested did not affect HBMEC monolayer disruptions. On the contrary, pre-treatment of A. castellanii-conditioned medium with phenylmethylsulfonyl fluoride, a serine protease inhibitor, or heating for 10 min at 95°C abolished HBMEC monolayer disruptions. Additionally, inhibitors of protease-activated receptors tested, failed to block A. castellanii-mediated HBMEC cytotoxicity and did not affect extracellular proteolytic activities of A. castellanii. Protease-activated receptors 1, 2 and 4 do not appear to play a role in A. castellanii

  12. Effects of Sainfoin (Onobrychis viciifolia Scop.) Condensed Tannins on Growth and Proteolysis by Four Strains of Ruminal Bacteria.

    Science.gov (United States)

    Jones, G A; McAllister, T A; Muir, A D; Cheng, K J

    1994-04-01

    Sainfoin leaf condensed tannins inhibited growth and protease activity in Butyrivibrio fibrisolvens A38 and Streptococcus bovis 45S1 but had little effect on Prevotella ruminicola B(1)4 or Ruminobacter amylophilus WP225. Tannins bound to cell coat polymers in all strains. Morphological changes in B. fibrisolvens and S. bovis implicated the cell wall as a target of tannin toxicity.

  13. Effects of Sainfoin (Onobrychis viciifolia Scop.) Condensed Tannins on Growth and Proteolysis by Four Strains of Ruminal Bacteria †

    Science.gov (United States)

    Jones, G. A.; McAllister, T. A.; Muir, A. D.; Cheng, K.-J.

    1994-01-01

    Sainfoin leaf condensed tannins inhibited growth and protease activity in Butyrivibrio fibrisolvens A38 and Streptococcus bovis 45S1 but had little effect on Prevotella ruminicola B14 or Ruminobacter amylophilus WP225. Tannins bound to cell coat polymers in all strains. Morphological changes in B. fibrisolvens and S. bovis implicated the cell wall as a target of tannin toxicity. Images PMID:16349244

  14. Evidence for Increased Aggressiveness in a Recent Widespread Strain of Puccinia striiformis f. sp. tritici Causing Stripe Rust of Wheat

    DEFF Research Database (Denmark)

    Milus, Eugene A; Kristensen, Kristian; Hovmøller, Mogens S

    2009-01-01

    Stripe rust (yellow rust) of wheat, caused by Puccinia striiformis f. sp. tritici, has become more severe in eastern United States, Australia, and elsewhere since 2000. Recent research has shown that this coincided with a global spread of two closely related strains that were similar based...... to the warm temperature regime for all variables. Based on these results and previously published models for stripe rust epidemics, recent severe stripe rust epidemics were most likely enhanced by the pathogen's increased aggressiveness, especially at higher temperature. Furthermore, these results demonstrate...... that wheat rust fungi can adapt to warmer temperatures and cause severe disease in previously unfavorable environments...

  15. Overexpression of a phosphatidic acid phosphatase type 2 leads to an increase in triacylglycerol production in oleaginous Rhodococcus strains.

    Science.gov (United States)

    Hernández, Martín A; Comba, Santiago; Arabolaza, Ana; Gramajo, Hugo; Alvarez, Héctor M

    2015-03-01

    Oleaginous Rhodococcus strains are able to accumulate large amounts of triacylglycerol (TAG). Phosphatidic acid phosphatase (PAP) enzyme catalyzes the dephosphorylation of phosphatidic acid (PA) to yield diacylglycerol (DAG), a key precursor for TAG biosynthesis. Studies to establish its role in lipid metabolism have been mainly focused in eukaryotes but not in bacteria. In this work, we identified and characterized a putative PAP type 2 (PAP2) encoded by the ro00075 gene in Rhodococcus jostii RHA1. Heterologous expression of ro00075 in Escherichia coli resulted in a fourfold increase in PAP activity and twofold in DAG content. The conditional deletion of ro00075 in RHA1 led to a decrease in the content of DAG and TAG, whereas its overexpression in both RHA1 and Rhodococcus opacus PD630 promoted an increase up to 10 to 15 % by cellular dry weight in TAG content. On the other hand, expression of ro00075 in the non-oleaginous strain Rhodococcus fascians F7 promoted an increase in total fatty acid content up to 7 % at the expense of free fatty acid (FFA), DAG, and TAG fractions. Moreover, co-expression of ro00075/atf2 genes resulted in a fourfold increase in total fatty acid content by a further increase of the FFA and TAG fractions. The results of this study suggest that ro00075 encodes for a PAP2 enzyme actively involved in TAG biosynthesis. Overexpression of this gene, as single one or with an atf gene, provides an alternative approach to increase the biosynthesis and accumulation of bacterial oils as a potential source of raw material for biofuel production.

  16. Genetic resistance to murine cryptococcosis: increased susceptibility in the CBA/N XID mutant strain of mice.

    Science.gov (United States)

    Marquis, G; Montplaisir, S; Pelletier, M; Mousseau, S; Auger, P

    1985-01-01

    In a survey of 301 normocomplementemic inbred mice (belonging to nine different strains: BALB/cN nu/nu and nu/+, CBA/N, C57BL/KsJ, C57BR/cdJ, CBA/CaJ, BRVR, DW/+, and C57BL/6J) for natural resistance to Cryptococcus neoformans, cumulative survival values were found to range from 12 to 22 days. When the average organ weights of infected animals were compared with reference values obtained in uninfected mice of the same age and genetic lineage, the following changes were documented. In the CBA/N strain, the mean spleen and brain weights increased 313 and 13.5%, respectively, whereas the mean liver weight remained unchanged. In the CBA/Ca strain, cerebral cryptococcosis was the dominant clinical feature, and a 54% increase in mean brain weight was recorded at the time of death. The averaged liver weight was drastically lower, whereas spleen weight values evinced a biphasic pattern of transient splenomegaly followed by involution. At the median time of death, CBA/N mice had significantly more cryptococci in the liver and spleen than corresponding CBA/Ca mice. In the (CBA/N X CBA/Ca)F1 mice, susceptibility to C. neoformans segregated according to the sex-linked inheritance of the X-linked immunodeficiency (xid) gene. It is concluded that (i) susceptibility to cryptococcosis is under multigenic control, (ii) the xid locus on the X chromosome influences susceptibility to cryptococcosis, and (iii) xid mice behave differently than CBA/Ca mice in their organ response during the course of the infection.

  17. Cannabinoids increase conditioned ultrasonic vocalisations and cat odour avoidance in rats: strain differences in drug-induced anxiety.

    Science.gov (United States)

    Arnold, Jonathon C; Dielenberg, Robert A; McGregor, Iain S

    2010-10-23

    Genetic disposition modulates the psychoactive effects of cannabis. Cannabinoids have a greater impact on brain regions that subserve anxiety in Wistar compared to Lewis strain rats. Here we aim to show that this correlates with strain differences in cannabinoid-induced anxiety-related behaviour. Lewis and Wistar rats were administered vehicle or the synthetic cannabinoid receptor agonist, CP 55,940 (10, 25 and 50μg/kg) before testing in the conditioned ultrasonic vocalization (USV), cat odour avoidance or open area avoidance models. Animals were placed in a chamber in which they had previously received footshock. Wistar but not Lewis rats re-exposed under the influence of all CP 55,940 doses emitted significantly more USVs than vehicle-treated rats. In the cat odour avoidance model, rats were exposed to cat odour and given the opportunity to hide in a small box. In Wistar but not Lewis rats, 50μg/kg of CP 55,940 magnified hiding behaviour promoted by cat odour exposure. Animals were also tested in the open area avoidance model which occurred in the same arena as the predatory avoidance model but without cat odour. In Wistar, but not Lewis rats, 25 and 50μg/kg of CP 55,940 increased the avoidance of the open space. CP 55,940 increased anxiety-related behaviour in Wistar rats but not Lewis rats providing a model to dissect the genetic basis of cannabinoid-induced anxiety. We show for the first time that cannabinoids magnify conditioned USVs and cat odour avoidance behaviour dependent on the strain being tested. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

  18. Adipose progenitor cells increase fibronectin matrix strain and unfolding in breast tumors

    Science.gov (United States)

    Chandler, E. M.; Saunders, M. P.; Yoon, C. J.; Gourdon, D.; Fischbach, C.

    2011-02-01

    Increased stiffness represents a hallmark of breast cancer that has been attributed to the altered physicochemical properties of the extracellular matrix (ECM). However, the role of fibronectin (Fn) in modulating the composition and mechanical properties of the tumor-associated ECM remains unclear. We have utilized a combination of biochemical and physical science tools to evaluate whether paracrine signaling between breast cancer cells and adipose progenitor cells regulates Fn matrix assembly and stiffness enhancement in the tumor stroma. In particular, we utilized fluorescence resonance energy transfer imaging to map the molecular conformation and stiffness of Fn that has been assembled by 3T3-L1 preadipocytes in response to conditioned media from MDA-MB231 breast cancer cells. Our results reveal that soluble factors secreted by tumor cells promote Fn expression, unfolding, and stiffening by adipose progenitor cells and that transforming growth factor-β serves as a soluble cue underlying these changes. In vivo experiments using orthotopic co-transplantation of primary human adipose-derived stem cells and MDA-MB231 into SCID mice support the pathological relevance of our results. Insights gained by these studies advance our understanding of the role of Fn in mammary tumorigenesis and may ultimately lead to improved anti-cancer therapies.

  19. Rayleigh scatter based order of magnitude increase in distributed temperature and strain sensing by simple UV exposure of optical fibre.

    Science.gov (United States)

    Loranger, Sébastien; Gagné, Mathieu; Lambin-Iezzi, Victor; Kashyap, Raman

    2015-06-16

    We present a technique to improve signal strength, and therefore sensitivity in distributed temperature and strain sensing (DTSS) using Frequency domain Rayleigh scatter. A simple UV exposure of a hydrogen loaded standard SMF-28 fibre core is shown to enhance the Rayleigh back-scattered light dramatically by ten-fold, independent of the presence of a Bragg grating, and is therefore created by the UV exposure alone. This increase in Rayleigh back-scatter allows an order-of-magnitude increase in temperature and strain resolution for DTSS compared to un-exposed SMF-28 fibre used as a sensing element. This enhancement in sensitivity is effective for cm range or more sensor gauge length, below which is the theoretical cross-correlation limit. The detection of a 20 mK temperature rise with a spatial resolution of 2 cm is demonstrated. This gain in sensitivity for SMF-28 is compared with a high Ge doped photosensitive fibre with a characteristically high NA. For the latter, the UV enhancement is also present although of lower amplitude, and enables an even lower noise level for sensing, due to the fibre's intrinsically higher Rayleigh scatter signal.

  20. Pace bowlers in cricket with history of lumbar stress fracture have increased risk of lower limb muscle strains, particularly calf strains

    Science.gov (United States)

    Orchard, John; Farhart, Patrick; Kountouris, Alex; James, Trefor; Portus, Marc

    2010-01-01

    Objective To assess whether a history of lumbar stress fracture in pace bowlers in cricket is a risk factor for lower limb muscle strains. Methods This was a prospective cohort risk factor study, conducted using injury data from contracted first class pace bowlers in Australia during seasons 1998–1999 to 2008–2009 inclusive. There were 205 pace bowlers, 33 of whom suffered a lumbar stress fracture when playing first class cricket. Risk ratios ([RR] with 95% confidence intervals[CI]) were calculated to compare the seasonal incidence of various injuries between bowlers with a prior history of lumbar stress fracture and those with no history of lumbar stress fracture. Results Risk of calf strain was strongly associated with prior lumbar stress fracture injury history (RR = 4.1; 95% CI: 2.4–7.1). Risks of both hamstring strain (RR = 1.5; 95% CI: 1.03–2.1) and quadriceps strain (RR = 2.0; 95% CI: 1.1–3.5) were somewhat associated with history of lumbar stress fracture. Risk of groin strain was not associated with history of lumbar stress fracture (RR = 0.7; 95% CI: 0.4–1.1). Other injuries showed little association with prior lumbar stress fracture, although knee cartilage injuries were more likely in the non-stress fracture group. Conclusion Bony hypertrophy associated with lumbar stress fracture healing may lead to subsequent lumbar nerve root impingement, making lower limb muscle strains more likely to occur. Confounders may be responsible for some of the findings. In particular, bowling speed is likely to be independently correlated with risk of lumbar stress fracture and risk of muscle strain. However, as the relationship between lumbar stress fracture history and calf strain was very strong, and that there is a strong theoretical basis for the connection, it is likely that this is a true association. PMID:24198555

  1. Pace bowlers in cricket with history of lumbar stress fracture have increased risk of lower limb muscle strains, particularly calf strains.

    Science.gov (United States)

    Orchard, John; Farhart, Patrick; Kountouris, Alex; James, Trefor; Portus, Marc

    2010-01-01

    To assess whether a history of lumbar stress fracture in pace bowlers in cricket is a risk factor for lower limb muscle strains. This was a prospective cohort risk factor study, conducted using injury data from contracted first class pace bowlers in Australia during seasons 1998-1999 to 2008-2009 inclusive. There were 205 pace bowlers, 33 of whom suffered a lumbar stress fracture when playing first class cricket. Risk ratios ([RR] with 95% confidence intervals[CI]) were calculated to compare the seasonal incidence of various injuries between bowlers with a prior history of lumbar stress fracture and those with no history of lumbar stress fracture. Risk of calf strain was strongly associated with prior lumbar stress fracture injury history (RR = 4.1; 95% CI: 2.4-7.1). Risks of both hamstring strain (RR = 1.5; 95% CI: 1.03-2.1) and quadriceps strain (RR = 2.0; 95% CI: 1.1-3.5) were somewhat associated with history of lumbar stress fracture. Risk of groin strain was not associated with history of lumbar stress fracture (RR = 0.7; 95% CI: 0.4-1.1). Other injuries showed little association with prior lumbar stress fracture, although knee cartilage injuries were more likely in the non-stress fracture group. Bony hypertrophy associated with lumbar stress fracture healing may lead to subsequent lumbar nerve root impingement, making lower limb muscle strains more likely to occur. Confounders may be responsible for some of the findings. In particular, bowling speed is likely to be independently correlated with risk of lumbar stress fracture and risk of muscle strain. However, as the relationship between lumbar stress fracture history and calf strain was very strong, and that there is a strong theoretical basis for the connection, it is likely that this is a true association.

  2. A mild pulsed electric field condition that improves acid tolerance, growth, and protease activity of Lactobacillus acidophilus LA-K and Lactobacillus delbrueckii subspecies bulgaricus LB-12.

    Science.gov (United States)

    Najim, N; Aryana, Kayanush J

    2013-06-01

    Pulsed electric field (PEF) processing involves the application of pulses of voltage for less than 1 s to fluid products placed between 2 electrodes. The effect of mild PEF on beneficial characteristics of probiotic bacteria Lactobacillus acidophilus and Lactobacillus delbrueckii ssp. bulgaricus is not clearly understood. The objective of this study was to determine the influence of mild PEF conditions on acid tolerance, growth, and protease activity of Lb. acidophilus LA-K and Lactobacillus delbrueckii ssp. bulgaricus LB-12. A pilot plant PEF system (OSU-4M; The Ohio State University, Columbus) was used. The PEF treatments were positive square unipolar pulse width of 3 µs, pulse period of 0.5s, electric field strength of 1 kV/cm, delay time of 20 µs, flow rate of 60 mL/min, and 40.5°C PEF treatment temperature. Both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 subjected to mild PEF conditions were acid tolerant until the end of the 120 min of incubation, unlike the Lb. bulgaricus control, which was not acid tolerant after 30 min. The mild PEF-treated Lb. acidophilus LA-K and Lb. bulgaricus LB-12 reached the logarithmic phase of growth an hour earlier than the control. Mild PEF conditions studied significantly improved acid tolerance, exponential growth, and protease activity of both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 compared with the control. The mild PEF conditions studied can be recommended for pretreating cultures to enhance these desirable attributes. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. Pace bowlers in cricket with history of lumbar stress fracture have increased risk of lower limb muscle strains, particularly calf strains

    Directory of Open Access Journals (Sweden)

    John Orchard

    2010-09-01

    Full Text Available John Orchard1, Patrick Farhart2, Alex Kountouris3, Trefor James3, Marc Portus31School of Public Health, University of Sydney, Australia; 2Punjab Kings XI team, Indian Premier League, India; 3Cricket Australia, Melbourne, AustraliaObjective: To assess whether a history of lumbar stress fracture in pace bowlers in cricket is a risk factor for lower limb muscle strains.Methods: This was a prospective cohort risk factor study, conducted using injury data from contracted first class pace bowlers in Australia during seasons 1998–1999 to 2008–2009 inclusive. There were 205 pace bowlers, 33 of whom suffered a lumbar stress fracture when playing first class cricket. Risk ratios ([RR] with 95% confidence intervals[CI] were calculated to compare the seasonal incidence of various injuries between bowlers with a prior history of lumbar stress fracture and those with no history of lumbar stress fracture.Results: Risk of calf strain was strongly associated with prior lumbar stress fracture injury history (RR = 4.1; 95% CI: 2.4–7.1. Risks of both hamstring strain (RR = 1.5; 95% CI: 1.03–2.1 and quadriceps strain (RR = 2.0; 95% CI: 1.1–3.5 were somewhat associated with history of lumbar stress fracture. Risk of groin strain was not associated with history of lumbar stress fracture (RR = 0.7; 95% CI: 0.4–1.1. Other injuries showed little association with prior lumbar stress fracture, although knee cartilage injuries were more likely in the non-stress fracture group.Conclusion: Bony hypertrophy associated with lumbar stress fracture healing may lead to subsequent lumbar nerve root impingement, making lower limb muscle strains more likely to occur. Confounders may be responsible for some of the findings. In particular, bowling speed is likely to be independently correlated with risk of lumbar stress fracture and risk of muscle strain. However, as the relationship between lumbar stress fracture history and calf strain was very strong, and that there is a

  4. Job strain associated with increases in ambulatory blood and pulse pressure during and after work hours among female hotel room cleaners.

    Science.gov (United States)

    Feaster, Matt; Krause, Niklas

    2018-03-22

    Previously documented elevated hypertension rates among Las Vegas hotel room cleaners are hypothesized to be associated with job strain. Job strain was assessed by questionnaire. Ambulatory blood pressure (ABP) was recorded among 419 female cleaners from five hotels during 18 waking hours. Multiple linear regression models assessed associations of job strain with ABP and pulse pressure for 18-h, work hours, and after work hours. Higher job strain was associated with increased 18-h systolic ABP, after work hours systolic ABP, and ambulatory pulse pressure. Dependents at home but not social support at work attenuated effects. Among hypertensive workers, job strain effects were partially buffered by anti-hypertensive medication. High job strain is positively associated with blood pressure among female hotel workers suggesting potential for primary prevention at work. Work organizational changes, stress management, and active ABP surveillance and hypertension management should be considered for integrated intervention programs. © 2018 Wiley Periodicals, Inc.

  5. Differences in SpeB protease activity among group A streptococci associated with superficial, invasive, and autoimmune disease.

    Directory of Open Access Journals (Sweden)

    Anhphan T Ly

    Full Text Available The secreted cysteine proteinase SpeB is an important virulence factor of group A streptococci (GAS, whereby SpeB activity varies widely among strains. To establish the degree to which SpeB activity correlates with disease, GAS organisms were recovered from patients with pharyngitis, impetigo, invasive disease or acute rheumatic fever (ARF, and selected for analysis using rigorous sampling criteria; >300 GAS isolates were tested for SpeB activity by casein digestion assays, and each GAS isolate was scored as a SpeB-producer or non-producer. Highly significant statistical differences (p < 0.01 in SpeB production are observed between GAS recovered from patients with ARF (41.5% SpeB-non-producers compared to pharyngitis (20.5%, invasive disease (16.7%, and impetigo (5.5%. SpeB activity differences between pharyngitis and impetigo isolates are also significant, whereas pharyngitis versus invasive isolates show no significant difference. The disproportionately greater number of SpeB-non-producers among ARF-associated isolates may indicate an altered transcriptional program for many rheumatogenic strains and/or a protective role for SpeB in GAS-triggered autoimmunity.

  6. Analysis of Genes for Succinoyl Trehalose Lipid Production and Increasing Production in Rhodococcus sp. Strain SD-74

    Science.gov (United States)

    Inaba, Tomohiro; Tokumoto, Yuta; Miyazaki, Yusuke; Inoue, Naoyuki; Maseda, Hideaki; Nakajima-Kambe, Toshiaki; Uchiyama, Hiroo

    2013-01-01

    Succinoyl trehalose lipids (STLs) are promising glycolipid biosurfactants produced from n-alkanes that are secreted by Rhodococcus species bacteria. These compounds not only exhibit unique interfacial properties but also demonstrate versatile biochemical actions. In this study, three novel types of genes involved in the biosynthesis of STLs, including a putative acyl coenzyme A (acyl-CoA) transferase (tlsA), fructose-bisphosphate aldolase (fda), and alkane monooxygenase (alkB), were identified. The predicted functions of these genes indicate that alkane metabolism, sugar synthesis, and the addition of acyl groups are important for the biosynthesis of STLs. Based on these results, we propose a biosynthesis pathway for STLs from alkanes in Rhodococcus sp. strain SD-74. By overexpressing tlsA, we achieved a 2-fold increase in the production of STLs. This study advances our understanding of bacterial glycolipid production in Rhodococcus species. PMID:24038682

  7. Increased household financial strain, the Great Recession and child health-findings from the UK Millennium Cohort Study.

    Science.gov (United States)

    McKenna, Caoimhe; Law, Catherine; Pearce, Anna

    2017-03-09

    There is a growing body of evidence associating financial strain (FS) with poor health but most of this research has been cross-sectional and adult-focused. During the 'Great Recession' many UK households experienced increased FS. The primary aim of this study was to determine the impact of increased FS on child health. We analysed the Millennium Cohort Study, a longitudinal study of children born in the UK between 2000 and 2002. Surveys at 7 years (T1, 2008) and 11 years (T2, 2012) spanned the 'Great Recession'. Three measures of increased FS were defined; 'became income poor' (self-reported household income dropped below the 'poverty line' between T1 and T2); 'developed difficulty managing' (parental report of being 'financially comfortable' at T1 and finding it 'difficult to manage' at T2); 'felt worse off' (parental report of feeling financially 'worse off' at T2 compared with T1). Poisson regression was used to estimate risk ratios (RR), adjusted risk ratios (aRR) and 95% CIs for six child health outcomes: measured overweight/obesity, problematic behaviour as scored by parents and teachers, and parental reports of fair/poor general health, long-standing illness and bedwetting at T2 (N=13 112). In subanalyses we limited our sample to those who were above the poverty line at T2. Compared with those who were not financially strained at both time points, children in households which experienced increased FS were at an increased risk of all unhealthy outcomes examined. In most cases, these increased risks persisted after adjustment for confounding and when limiting the sample to those above the poverty line. FS is associated with a range of new or continued poor child health outcomes. During times of widespread economic hardship, such as the 'Great Recession', measures should be taken to buffer children and their families from the impact of FS, and these should not be limited to those who are income poor. Published by the BMJ Publishing Group Limited. For

  8. Antibiotic resistance in Pseudomonas aeruginosa strains with increased mutation frequency due to inactivation of the DNA oxidative repair system.

    Science.gov (United States)

    Mandsberg, L F; Ciofu, O; Kirkby, N; Christiansen, L E; Poulsen, H E; Høiby, N

    2009-06-01

    The chronic Pseudomonas aeruginosa infection of the lungs of cystic fibrosis (CF) patients is characterized by the biofilm mode of growth and chronic inflammation dominated by polymorphonuclear leukocytes (PMNs). A high percentage of P. aeruginosa strains show high frequencies of mutations (hypermutators [HP]). P. aeruginosa is exposed to oxygen radicals, both those generated by its own metabolism and especially those released by a large number of PMNs in response to the chronic CF lung infection. Our work therefore focused on the role of the DNA oxidative repair system in the development of HP and antibiotic resistance. We have constructed and characterized mutT, mutY, and mutM mutants in P. aeruginosa strain PAO1. The mutT and mutY mutants showed 28- and 7.5-fold increases in mutation frequencies, respectively, over that for PAO1. These mutators had more oxidative DNA damage (higher levels of 7,8-dihydro-8-oxodeoxyguanosine) than PAO1 after exposure to PMNs, and they developed resistance to antibiotics more frequently. The mechanisms of resistance were increased beta-lactamase production and overexpression of the MexCD-OprJ efflux-pump. Mutations in either the mutT or the mutY gene were found in resistant HP clinical isolates from patients with CF, and complementation with wild-type genes reverted the phenotype. In conclusion, oxidative stress might be involved in the development of resistance to antibiotics. We therefore suggest the possible use of antioxidants for CF patients to prevent the development of antibiotic resistance.

  9. Increased prevalence of carbapenem resistant Enterobacteriaceae in hospital setting due to cross-species transmission of the bla NDM-1 element and clonal spread of progenitor resistant strains.

    Science.gov (United States)

    Wang, Xuan; Chen, Gongxiang; Wu, Xiaoyan; Wang, Liangping; Cai, Jiachang; Chan, Edward W; Chen, Sheng; Zhang, Rong

    2015-01-01

    This study investigated the transmission characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains collected from a hospital setting in China, in which consistent emergence of CRE strains were observable during the period of May 2013 to February 2014. Among the 45 CRE isolates tested, 21 (47%) strains were found to harbor the bla NDM-1 element, and the rest of 24 CRE strains were all positive for bla KPC-2. The 21 bla NDM-1-borne strains were found to comprise multiple Enterobacteriaceae species including nine Enterobacter cloacae, three Escherichia coli, three Citrobacter freundii, two Klebsiella pneumoniae, two Klebsiella oxytoca, and two Morganella morganii strains, indicating that cross-species transmission of bla NDM-1 is a common event. Genetic analyses by PFGE and MLST showed that, with the exception of E. coli and E. cloacae, strains belonging to the same species were often genetically unrelated. In addition to bla NDM-1, several CRE strains were also found to harbor the bla KPC-2, bla VIM-1, and bla IMP-4 elements. Conjugations experiments confirmed that the majority of carbapenem resistance determinants were transferable. Taken together, our findings suggest that transmission of mobile resistance elements among members of Enterobacteriaceae and clonal spread of CRE strains may contribute synergistically to a rapid increase in the population of CRE in clinical settings, prompting a need to implement more rigorous infection control measures to arrest such vicious transmission cycle in CRE-prevalent areas.

  10. Increased Air Velocity Reduces Thermal and Cardiovascular Strain in Young and Older Males during Humid Exertional Heat Stress.

    Science.gov (United States)

    Wright Beatty, Heather E; Hardcastle, Stephen G; Boulay, Pierre; Flouris, Andreas D; Kenny, Glen P

    2015-01-01

    Older adults have been reported to have a lower evaporative heat loss capacity than younger adults during exercise when full sweat evaporation is permitted. However, it is unclear how conditions of restricted evaporative and convective heat loss (i.e., high humidity, clothing insulation) alter heat stress. to the purpose of this study was to examine the heat stress responses of young and older males during and following exercise in a warm/humid environment under two different levels of air velocity. Ten young (YOUNG: 24±2 yr) and 10 older (OLDER: 59±3 yr) males, matched for body surface area performed 4×15-min cycling bouts (15-min rest) at a fixed rate of heat production (400 W) in warm/humid conditions (35°C, 60% relative humidity) under 0.5 (Low) and 3.0 (High) m·s(-1) air velocity while wearing work coveralls. Rectal (Tre) and mean skin (MTsk) temperatures, heart rate (HR), local sweat rate, % max skin blood flow (SkBF) (recovery only), and blood pressure (recovery only) were measured. High air velocity reduced core and skin temperatures (p 0.05) but was more effective in reducing cardiovascular strain (absolute and % max HR; p velocity reduced the number of males surpassing the 38.0°C Tre threshold from 90% (Low) to 50% (High). Despite age-related local heat loss differences, YOUNG and OLDER males had similar levels of heat stress during intermittent exercise in warm and humid conditions while wearing work coveralls. Increased air velocity was effective in reducing heat stress equally, and cardiovascular strain to a greater extent, in YOUNG and OLDER males, and may be useful for mitigating heat stress in all workers.

  11. An assay to monitor HIV-1 protease activity for the identification of novel inhibitors in T-cells.

    Directory of Open Access Journals (Sweden)

    Brett J Hilton

    Full Text Available The emergence of resistant HIV strains, together with the severe side-effects of existing drugs and lack of development of effective anti-HIV vaccines highlight the need for novel antivirals, as well as innovative methods to facilitate their discovery. Here, we have developed an assay in T-cells to monitor the proteolytic activity of the HIV-1 protease (PR. The assay is based on the inducible expression of HIV-1 PR fused within the Gal4 DNA-binding and transactivation domains. The fusion protein binds to the Gal4 responsive element and activates the downstream reporter, enhanced green fluorescent protein (eGFP gene only in the presence of an effective PR Inhibitor (PI. Thus, in this assay, eGFP acts as a biosensor of PR activity, making it ideal for flow cytometry based screening. Furthermore, the assay was developed using retroviral technology in T-cells, thus providing an ideal environment for the screening of potential novel PIs in a cell-type that represents the natural milieu of HIV infection. Clones with the highest sensitivity, and robust, reliable and reproducible reporter activity, were selected. The assay is easily adaptable to other PR variants, a multiplex platform, as well as to high-throughput plate reader based assays and will greatly facilitate the search for novel peptide and chemical compound based PIs in T-cells.

  12. Paraquat increases superoxide dismutase activity and radiation resistance in two mouse lymphoma L5178Y cell strains of different radiosensitivities

    International Nuclear Information System (INIS)

    Jaworska, A.; Rosiek, O.

    1991-01-01

    It is shown that paraquat treatment (1 h, 1 x 10 -5 mol/l) increases the activity of superoxide dismutase (SOD) in L5178Y (LY) R and S cells by about three times. When combined with X-irradiation, 0.5 h of treatment preceding irradiation increased the SOD activity two-fold and the α/β ratio three-fold, as estimated from the X-ray survival curves. LY-S cells were more sensitive than LY-R cells to treatment with paraquat alone. These results indicate that SOD may be a radioprotective enzyme in LY strains and that LY-S cells are particularly sensitive to superoxide radicals as a result of a relatively low SOD activity. This explains their sensitivity to paraquat, which generates O 2 - , and to X-rays. The low SOD level may also explain the higher initial DNA damage in X-irradiated LY-S than LY-R cells. (author)

  13. Helicobacter pylori strains harboring babA2 from Indian sub population are associated with increased virulence in ex vivo study.

    Science.gov (United States)

    Ghosh, Prachetash; Sarkar, Avijit; Ganguly, Mou; Raghwan; Alam, Jawed; De, Ronita; Mukhopadhyay, Asish K

    2016-01-01

    The babA2 gene along with the cagA and vacA of Helicobacter pylori has been considered as a risk factor for the disease outcome in certain populations. This study was aimed to understand the role of babA2 of H. pylori with the background of cagA and vacA in disease manifestations in Indian sub population. A total of 114 H. pylori strains isolated from duodenal ulcer (DU) (n = 53) and non-ulcer dyspepsia (NUD) patients (n = 61) were screened for the prevalence of these virulence markers by PCR. The comparative study of IL-8 production and apoptosis were done by co-culturing the AGS cell line with H. pylori strains with different genotypes. Adherence assay was performed with babA2 positive and negative strains. Two isogenic mutants of babA2 were constructed and the aforesaid comparative studies were carried out. PCR results indicated that 90.6 % (48/53), 82 % (50/61) and 73.6 % (39/53) strains from DU patients were positive for cagA, vacA, and babA2, respectively. Whereas the prevalence of these genes in NUD subjects were 70.5 % (43/61); 69.8 % (37/53), and 65.6 % (39/61), respectively. Although adherence to AGS cells was comparable among strains with babA2 positive and negative genotypes, but the triple positive strains could induce highest degree of IL-8 production and apoptosis, followed by the cagA (-)/vacA (-)/babA2 (+) strains and triple negative strains, respectively. The wild type strains showed significantly higher IL-8 induction as well as apoptosis in ex vivo than its isogenic mutant of babA2. PCR study demonstrated that there was no significant association between the distribution of babA2 genotype or of triple positive strains and disease outcome in this sub population. The adherence assay showed that there was no significant difference in the extent of adherence to AGS cells among babA2 positive and negative strains. But the ex vivo study indicated that the triple positive or even the babA2 only positive strains are involved in increased

  14. Increased transmission of Mycobacterium tuberculosis Beijing genotype strains associated with resistance to streptomycin: a population-based study.

    NARCIS (Netherlands)

    Buu, T.N.; Soolingen, D. van; Huyen, M.N.; Lan, N.T.; Quy, H.T.; Tiemersma, E.W.; Kremer, K.; Borgdorff, M.W.; Cobelens, F.G.

    2012-01-01

    BACKGROUND: Studies have shown that the Mycobacterium tuberculosis Beijing genotype is an emerging pathogen that is frequently associated with drug resistance. This suggests that drug resistant Beijing strains have a relatively high transmission fitness compared to other drug-resistant strains.

  15. Increased Transmission of Mycobacterium tuberculosis Beijing Genotype Strains Associated with Resistance to Streptomycin: A Population-Based Study

    NARCIS (Netherlands)

    Buu, Tran N.; van Soolingen, Dick; Huyen, Mai N. T.; Lan, Nguyen T. N.; Quy, Hoang T.; Tiemersma, Edine W.; Kremer, Kristin; Borgdorff, Martien W.; Cobelens, Frank G. J.

    2012-01-01

    Background: Studies have shown that the Mycobacterium tuberculosis Beijing genotype is an emerging pathogen that is frequently associated with drug resistance. This suggests that drug resistant Beijing strains have a relatively high transmission fitness compared to other drug-resistant strains.

  16. Coagulation factor VIIa-mediated protease-activated receptor 2 activation leads to β-catenin accumulation via the AKT/GSK3β pathway and contributes to breast cancer progression.

    Science.gov (United States)

    Roy, Abhishek; Ansari, Shabbir A; Das, Kaushik; Prasad, Ramesh; Bhattacharya, Anindita; Mallik, Suman; Mukherjee, Ashis; Sen, Prosenjit

    2017-08-18

    Cell migration and invasion are very characteristic features of cancer cells that promote metastasis, which is one of the most common causes of mortality among cancer patients. Emerging evidence has shown that coagulation factors can directly mediate cancer-associated complications either by enhancing thrombus formation or by initiating various signaling events leading to metastatic cancer progression. It is well established that, apart from its distinct role in blood coagulation, coagulation factor FVIIa enhances aggressive behaviors of breast cancer cells, but the underlying signaling mechanisms still remain elusive. To this end, we investigated FVIIa's role in the migration and invasiveness of the breast cancer cell line MDA-MB-231. Consistent with previous observations, we observed that FVIIa increased the migratory and invasive potential of these cells. We also provide molecular evidence that protease-activated receptor 2 activation followed by PI3K-AKT activation and GSK3β inactivation is involved in these processes and that β-catenin, a well known tumor-regulatory protein, contributes to this signaling pathway. The pivotal role of β-catenin was further indicated by the up-regulation of its downstream targets cyclin D1, c-Myc, COX-2, MMP-7, MMP-14, and Claudin-1. β-Catenin knockdown almost completely attenuated the FVIIa-induced enhancement of breast cancer migration and invasion. These findings provide a new perspective to counteract the invasive behavior of breast cancer, indicating that blocking PI3K-AKT pathway-dependent β-catenin accumulation may represent a potential therapeutic approach to control breast cancer. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Protease-activated receptor 1 suppresses Helicobacter pylori gastritis via the inhibition of macrophage cytokine secretion and interferon regulatory factor 5.

    Science.gov (United States)

    Chionh, Y-T; Ng, G Z; Ong, L; Arulmuruganar, A; Stent, A; Saeed, M A; Wee, J Lk; Sutton, P

    2015-01-01

    Chronic gastritis from Helicobacter pylori infection is a major factor in the development of gastric adenocarcinoma. Factors that regulate gastritis severity are important in determining which individuals are susceptible to H. pylori-associated disease. Although protease-activated receptor 1 (PAR1) has been identified as one such host factor, its mechanism of action is unknown. Using chimeric mice, we demonstrated that PAR1-mediated protection against H. pylori gastritis requires bone marrow-derived cells. Analyses of the gastric mucosa revealed that PAR1 suppresses cellular infiltration and both T helper type 1 (Th1) and T helper type 17 (Th17) responses to infection. Moreover, PAR1 expression was associated with reduced vaccine-mediated protection against H. pylori. Analyses of H. pylori-stimulated macrophages revealed that PAR1 activation suppressed secretion of interleukin (IL)-12 and IL-23, key drivers of Th1 and Th17 immunity, respectively. Furthermore, PAR1 suppressed interferon regulatory factor 5 (IRF5), an important transcription factor for IL-12 and IL-23, both in the infected mucosa and following bacterial stimulation. PAR1 suppression of IRF5 and IL-12/23 secretion by macrophages provides a novel mechanism by which the host suppresses the mucosal Th1 and Th17 response to H. pylori infection. Dysregulation of this process is likely an important factor in the susceptibility of some individuals to H. pylori-associated disease.

  18. Molecular dynamics and docking simulation of a natural variant of Activated Protein C with impaired protease activity: implications for integrin-mediated antiseptic function.

    Science.gov (United States)

    D'Ursi, Pasqualina; Orro, Alessandro; Morra, Giulia; Moscatelli, Marco; Trombetti, Gabriele; Milanesi, Luciano; Rovida, Ermanna

    2015-01-01

    Activated Protein C (APC) is a multifunctional serine protease, primarily known for its anticoagulant function in the coagulation system. Several studies have already elucidated its role in counteracting apoptosis and inflammation in cells, while significant effort is still ongoing for defining its involvement in sepsis. Earlier literature has shown that the antiseptic function of APC is mediated by its binding to leukocyte integrins, which is due to the presence of the integrin binding motif Arg-Gly-Asp at the N-terminus of the APC catalytic chain. Many natural mutants have been identified in patients with Protein C deficiency diagnosis including a variant of specificity pocket (Gly216Asp). In this work, we present a molecular model of the complex of APC with αVβ3 integrin obtained by protein-protein docking approach. A computational analysis of this variant is hereby presented, based on molecular dynamics and docking simulations, aiming at investigating the effects of the Gly216Asp mutation on the protein conformation and inferring its functional implications. Our study shows that such mutation is likely to impair the protease activity while preserving the overall protein fold. Moreover, superposition of the integrin binding motifs in wild-type and mutant forms suggests that the interaction with integrin can still occur and thus the mutant is likely to retain its antiseptic function related to the neutrophyl integrin binding. Therapeutic applications could result in this APC mutant which retains antiseptic function without anticoagulant side effects.

  19. Protease activity of PprI facilitates DNA damage response: Mn2+-dependence and substrate sequence-specificity of the proteolytic reaction.

    Directory of Open Access Journals (Sweden)

    Yunguang Wang

    Full Text Available The extremophilic bacterium Deinococcus radiodurans exhibits an extraordinary resistance to ionizing radiation. Previous studies established that a protein named PprI, which exists only in the Deinococcus-Thermus family, acts as a general switch to orchestrate the expression of a number of DNA damage response (DDR proteins involved in cellular radio-resistance. Here we show that the regulatory mechanism of PprI depends on its Mn(2+-dependent protease activity toward DdrO, a transcription factor that suppresses DDR genes' expression. Recognition sequence-specificity around the PprI cleavage site is essential for DNA damage repair in vivo. PprI and DdrO mediate a novel DNA damage response pathway differing from the classic LexA-mediated SOS response system found in radiation-sensitive bacterium Escherichia coli. This PprI-mediated pathway in D. radiodurans is indispensable for its extreme radio-resistance and therefore its elucidation significantly advances our understanding of the DNA damage repair mechanism in this amazing organism.

  20. Interaction of Protease-Activated Receptor 2 with G Proteins and Beta-Arrestin 1 Studied by Bioluminescence Resonance Energy Transfer

    Directory of Open Access Journals (Sweden)

    Mohammed Akli eAyoub

    2013-12-01

    Full Text Available G protein-coupled receptors (GPCRs are well recognized as being able to activate several signaling pathways through the activation of different G proteins as well as other signaling proteins such as beta-arrestins. Therefore, understanding how such multiple GPCR-mediated signaling can be integrated constitute an important aspect. Here, we applied bioluminescence resonance energy transfer (BRET to shed more light on the G protein coupling profile of trypsin receptor, or protease-activated receptor 2 (PAR2, and its interaction with beta-arrestin1. Using YFP and Rluc fusion constructs expressed in COS-7 cells, BRET data revealed a pre-assembly of PAR2 with both Galphai1 and Galphao and a rapid and transient activation of these G proteins upon receptor activation. In contrast, no preassembly of PAR2 with Galpha12 could be detected and their physical association can be measured with a very slow and sustained kinetics similar to that of beta-arrestin1 recruitment. These data demonstrate the coupling of PAR2 with Galphai1, Galphao and Galpha12 in COS-7 cells with differences in the kinetics of GPCR-G protein coupling, a parameter that very likely influences the cellular response. Moreover, this further illustrates that preassembly or agonist-induced G protein interaction depends on receptor-G protein pairs indicating another level of complexity and regulation of the signaling of GPCR-G protein complexes and its multiplicity.

  1. Neutrophil Cathepsin G, but Not Elastase, Induces Aggregation of MCF-7 Mammary Carcinoma Cells by a Protease Activity-Dependent Cell-Oriented Mechanism

    Directory of Open Access Journals (Sweden)

    Satoru Yui

    2014-01-01

    Full Text Available We previously found that a neutrophil serine protease, cathepsin G, weakens adherence to culture substrates and induces E-cadherin-dependent aggregation of MCF-7 human breast cancer cells through its protease activity. In this study, we examined whether aggregation is caused by degradation of adhesion molecules on the culture substrates or through an unidentified mechanism. We compared the effect of treatment with cathepsin G and other proteases, including neutrophil elastase against fibronectin- (FN- coated substrates. Cathepsin G and elastase potently degraded FN on the substrates and induced aggregation of MCF-7 cells that had been subsequently seeded onto the substrate. However, substrate-bound cathepsin G and elastase may have caused cell aggregation. After inhibiting the proteases on the culture substrates using the irreversible inhibitor phenylmethylsulfonyl fluoride (PMSF, we examined whether aggregation of MCF-7 cells was suppressed. PMSF attenuated cell aggregation on cathepsin G-treated substrates, but the effect was weak in cells pretreated with high concentrations of cathepsin G. In contrast, PMSF did not suppress cell aggregation on elastase-treated FN. Moreover, cathepsin G, but not elastase, induced aggregation on poly-L-lysine substrates which are not decomposed by these enzymes, and the action of cathepsin G was nearly completely attenuated by PMSF. These results suggest that cathepsin G induces MCF-7 aggregation through a cell-oriented mechanism.

  2. Anticipation of Artemia sp. supply in the larviculture of the barber goby Elacatinus figaro (Gobiidae: Teleostei influenced growth, metamorphosis and alkaline protease activity

    Directory of Open Access Journals (Sweden)

    Maria Fernanda da Silva-Souza

    2015-09-01

    Full Text Available The barber goby Elacatinus figaro is considered endangered due to overexploitation by the ornamental industry. Farming marine ornamental fishes, especially the threatened ones, can be one of the measures to minimize the pressure on the natural stocks. Among the priority issues for their production is the determination of the most appropriate feeding management. The feeding protocol commonly used in the larviculture of barber goby, when the start of Artemia sp. offer occurred at the 18th DAH (days after hatching (treatment T18, was modified, by anticipating brine shrimp supply in 6 days (treatment T12. Alkaline proteases activity, growth and metamorphosis of larvae were evaluated in both protocols. Juveniles at T12 showed higher weight (0.04 ± 0.001 g and lower activity of total alkaline proteases (1.3 ± 0.2 mU mg-1 protein compared to T18 (0.02 ± 0.001 g; 2.8 ± 0.4 mU mg-1 protein, respectively. With anticipation of brine shrimp, the commencing and end of larval transformation was observed earlier (at 24 and 34 DAH, respectively in comparison to those with the supply of Artemia sp. at 18 DAH (27 and 41 DAH, respectively. Thus, the Artemia sp. anticipation was beneficial during the larviculture of the barber goby, considering that larvae reached metamorphosis earlier.

  3. [Roles of protease-activated receptor-2 (PAR-2), a G protein-coupled receptor, in modulation of exocrine gland functions].

    Science.gov (United States)

    Nishikawa, Hiroyuki

    2006-07-01

    Protease-activated receptor-2 (PAR-2), a G protein-coupled receptor, is activated by proteolytic unmasking of the N-terminal extracellular tethered ligand that presumably binds to the extracellular loop 2 of the receptor itself. PAR-2 is widely distributed in the mammalian body and plays various roles in biological events in the cardiovascular, respiratory, alimentary, and central neurons systems. PAR-2-activating peptides administered systemically to mice and rats trigger prompt salivation in vivo. In an in vitro study, PAR-2 agonists including the endogenous PAR-2 activator trypsin induce secretion of amylase and mucin from isolated rat parotid glands and sublingual glands, respectively. PAR-2-activating peptides administered systemically also modulate pancreatic exocrine secretion in vivo as well as in vitro. In the gastric mucosa, PAR-2 stimulation enhances secretion of mucus and pepsinogen and suppresses acid secretion. Tear secretion can also be caused by PAR-2-related peptides in PAR-2-dependent and -independent manners. PAR-2 thus plays a general or key role in the regulation of exocrine secretion. This review focuses on the physiologic and/or pathophysiologic roles of PAR-2 in glandular exocrine secretion. The possibility of PAR-2 as a target for drug development is also discussed.

  4. Is there a potential relationship between prior hamstring strain injury and increased risk for future anterior cruciate ligament injury?

    Science.gov (United States)

    Opar, David A; Serpell, Benjamin G

    2014-02-01

    Hamstring strain injuries (HSIs) are the most prevalent injury in a number of sports, and while anterior cruciate ligament (ACL) injuries are less common, they are far more severe and have long-term implications, such as an increased risk of developing osteoarthritis later in life. Given the high incidence and severity of these injuries, they are key targets of injury preventive programs in elite sport. Evidence has shown that a previous severe knee injury (including ACL injury) increases the risk of HSI; however, whether the functional deficits that occur after HSI result in an increased risk of ACL injury has yet to be considered. In this clinical commentary, we present evidence that suggests that the link between previous HSI and increased risk of ACL injury requires further investigation by drawing parallels between deficits in hamstring function after HSI and in women athletes, who are more prone to ACL injury than men athletes. Comparisons between the neuromuscular function of the male and female hamstring has shown that women display lower hamstring-to-quadriceps strength ratios during isokinetic knee flexion and extension, increased activation of the quadriceps compared with the hamstrings during a stop-jump landing task, a greater time required to reach maximal isokinetic hamstring torque, and lower integrated myoelectrical hamstring activity during a sidestep cutting maneuver. Somewhat similarly, in athletes with a history of HSI, the previously injured limb, compared with the uninjured limb, displays lower eccentric knee flexor strength, a lower hamstrings-to-quadriceps strength ratio, lower voluntary myoelectrical activity during maximal knee flexor eccentric contraction, a lower knee flexor eccentric rate of torque development, and lower voluntary myoelectrical activity during the initial portion of eccentric contraction. Given that the medial and lateral hamstrings have different actions at the knee joint in the coronal plane, which hamstring head is

  5. Neuroinflammation-Induced Interactions between Protease-Activated Receptor 1 and Proprotein Convertases in HIV-Associated Neurocognitive Disorder.

    Science.gov (United States)

    Kim, WooJin; Zekas, Erin; Lodge, Robert; Susan-Resiga, Delia; Marcinkiewicz, Edwidge; Essalmani, Rachid; Mihara, Koichiro; Ramachandran, Rithwik; Asahchop, Eugene; Gelman, Benjamin; Cohen, Éric A; Power, Christopher; Hollenberg, Morley D; Seidah, Nabil G

    2015-11-01

    The proprotein convertases (PCs) furin, PC5, PACE4, and PC7 cleave secretory proteins after basic residues, including the HIV envelope glycoprotein (gp160) and Vpr. We evaluated the abundance of PC mRNAs in postmortem brains of individuals exhibiting HIV-associated neurocognitive disorder (HAND), likely driven by neuroinflammation and neurotoxic HIV proteins (e.g., envelope and Vpr). Concomitant with increased inflammation-related gene expression (interleukin-1β [IL-1β]), the mRNA levels of the above PCs are significantly increased, together with those of the proteinase-activated receptor 1 (PAR1), an inflammation-associated receptor that is cleaved by thrombin at ProArg41↓ (where the down arrow indicates the cleavage location), and potentially by PCs at Arg41XXXXArg46↓. The latter motif in PAR1, but not its R46A mutant, drives its interactions with PCs. Indeed, PAR1 upregulation leads to the inhibition of membrane-bound furin, PC5B, and PC7 and inhibits gp160 processing and HIV infectivity. Additionally, a proximity ligation assay revealed that furin and PC7 interact with PAR1. Reciprocally, increased furin expression reduces the plasma membrane abundance of PAR1 by trapping it in the trans-Golgi network. Furthermore, soluble PC5A/PACE4 can target/disarm cell surface PAR1 through cleavage at Arg46↓. PACE4/PC5A decreased calcium mobilization induced by thrombin stimulation. Our data reveal a new PC-PAR1-interaction pathway, which offsets the effects of HIV-induced neuroinflammation, viral infection, and potentially the development of HAND. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. F16357, a novel protease-activated receptor 1 antagonist, improves urodynamic parameters in a rat model of interstitial cystitis.

    Science.gov (United States)

    Monjotin, N; Gillespie, J; Farrié, M; Le Grand, B; Junquero, D; Vergnolle, N

    2016-07-01

    The aims of the present study were to characterize the role of PAR1 in rat bladder under inflammatory conditions and determine whether a selective PAR1 antagonist, F16357, can prevent the pathophysiological symptoms of cyclophosphamide-induced interstitial cystitis (IC). Immunohistochemistry, contractile activity in isolated bladder and urodynamics were determined before and after cyclophosphamide treatment. F16357 was administered intravesically during the acute phase of inflammation, and effects on PAR1 and PAR1-related bladder contraction evaluated 24 h after cyclophosphamide injection. Urodynamics and associated voided volumes were recorded 7 and 24 h after cyclophosphamide. In control conditions, PAR1 was present only in some umbrella cells. Cyclophosphamide disrupted the urothelium and expression of PAR1 by all remaining urothelial cells. After F16357 treatment, urothelial damage was absent and PAR1 immunoreactivity similar to control tissues. Thrombin and TFLLR-NH2 induced bladder contractions. These were increased in inflammatory conditions and antagonized by F16357 in a concentration-dependent manner. In telemetric experiments, furosemide increased urine production and voiding frequency for 60 min, 7 h after cyclophosphamide injection. Intravesical administration of F16357 blocked these changes with a return to a physiological profile; 24 h after cyclophosphamide, the volume of micturition was still lower with no increase in number of micturitions. F16357 30 μM reduced the number of micturitions and improved bladder capacity, but did not affect diuresis. Under similar experimental conditions, lidocaine 2% induced comparable effects. PAR1 is expressed in rat bladder, overactivated in inflammatory conditions and involved in bladder function and sensation. F16357 could represent an interesting candidate for IC treatment. © 2016 Laboratories Pierre Febre. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British

  7. Apical serine protease activity is necessary for assembly of a high-resistance renal collecting duct epithelium

    DEFF Research Database (Denmark)

    Steensgaard, Mette; Svenningsen, Per; Tinning, Anne R

    2010-01-01

    Abstract AIM: We hypothesized that the serine protease prostasin is necessary for differentiation of a high resistance renal collecting duct epithelium governed by glucocorticoid. METHODS: Postnatal rat kidney and adult human kidney was used to study expression and localization of prostasin...... 21) and was detected in collecting ducts. Immunoreactive prostasin was associated with collecting ducts and loops of Henle in human kidney. In rat, adrenalectomy at day 10 had no effect on prostasin mRNA level in kidney at day 20. Cultured M-1 cells exhibited parallel increases in prostasin m...

  8. Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres.

    Science.gov (United States)

    Ibrahim, Abdelnasser Salah Shebl; Al-Salamah, Ali A; El-Toni, Ahmed M; Almaary, Khalid S; El-Tayeb, Mohamed A; Elbadawi, Yahya B; Antranikian, Garabed

    2016-01-29

    The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS-NH₂ nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher V(max), k(cat) and k(cat)/K(m), than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media.

  9. Increasing Antimicrobial Resistance of Vibrio cholerae OI Biotype EI Tor Strains Isolated in a Tertiary-care Centre in India

    Science.gov (United States)

    Mandal, Jharna; Dinoop, K.P.

    2012-01-01

    The antimicrobial susceptibility patterns are on constant change with the recent emergence of multidrug-resistant strains of most bacteria. Results of recent studies in India showed that most isolates of Vibrio cholerae O1 were resistant to the commonly-used antibiotics. The study was conducted to determine the antibiotic susceptibility patterns of V. cholerae O1 isolated during 2008-2010 at the hospital of the Jawaharlal Nehru Institute of Post Graduate Medical Education and Research, Puducherry, India. In total, 154 strains of V. cholerae O1 from 2,658 stool specimens were reported during January 2008–December 2010—34 in 2008, 2 in 2009, and 118 in 2010. The isolates of V. cholerae O1 were subjected to antimicrobial susceptibili-ty testing using the Kirby-Bauer method. The antibiotic disks tested were tetracycline (30 μg), furazolidone (100 μg), ampicillin (10 μg), ceftriaxone (30 μg), and ciprofloxacin (5 μg). Escherichia coli ATCC 25922 was used as the control organism. The minimum inhibitory concentrations (MICs) of ceftriaxone, ciprofloxacin, and tetracycline were determined using the agar dilution method for all the strains. The E-test method was used for the strains which had either intermediate resistance or were resistant to the antibiotics by the agar dilution method. The results of the agar dilution corroborated the results of the E-test. The MIC of ceftriaxone in 151 strains was resistant to ceftriaxone by the disc-diffusion test. The MIC of ciprofloxacin in 150 strains was 32 μg/mL, and the MIC of ciprofloxacin was >8 μg/mL. These four strains were resistant to both tetracycline and ciprofloxacin by the disc-diffusion test and were exclusive of the three ceftriaxone-resistant strains. The majority of the isolates were obtained from children aged 0-5 year(s)—70.3% (83 of 118) and 41.2% (14 of 34) were reported in 2010 and 2008 respectively. Since treating severe cases of cholera with antibiotics is important, the continuing spread of

  10. Expression of protease-activated receptor-2 (PAR-2) is related to advanced clinical stage and adverse prognosis in ovarian clear cell carcinoma.

    Science.gov (United States)

    Aman, Murasaki; Ohishi, Yoshihiro; Imamura, Hiroko; Shinozaki, Tomoko; Yasutake, Nobuko; Kato, Kiyoko; Oda, Yoshinao

    2017-06-01

    Recent studies demonstrated that protease-activated receptor-2 (PAR-2) correlates with tumor progression in various tissues. On the other hand, oxidative stress arising from endometriosis has been considered a cause of carcinogenesis in ovarian clear cell carcinoma (OCCC). We previously demonstrated that oxidative stress up-regulates PAR-2 expression, and we conducted the present study to investigate the PAR-2 expression and its relation to clinicopathological factors and oxidative stress in OCCC. We performed an immunohistochemical evaluation in 95 cases of OCCC. For the evaluation of oxidative stress markers, 31 cases of ovarian endometrioid carcinoma (OEC) were also examined. No significant differences in the expression of cyclooxygenase-2 and inducible nitric oxide synthase were observed between OCCC and OEC. Sixty-two percent of the OCCC cases showed high 8-hydroxydeoxyguanosine expression, whereas all of the OEC cases showed almost negative immunoreactivities. The presence of endometriosis did not affect the expression of these oxidative stress markers or prognosis. High PAR-2 expression was observed in 20% (14/71) of the early International Federation of Gynecology and Obstetrics (FIGO) stage cases and 58% (14/24) of the advanced FIGO stage cases. High PAR-2 expression was significantly correlated with advanced FIGO stage and shorter overall survival. We found no correlations between PAR-2 expression and oxidative stress in OCCC. Our results suggest that PAR-2 plays an important role in the progression of OCCC. The expression of 8-hydroxydeoxyguanosine is a characteristic finding of OCCC, indicating that the injury of DNA by oxidative stress may be involved in the carcinogenesis of OCCC. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Salmon and human thrombin differentially regulate radicular pain, glial-induced inflammation and spinal neuronal excitability through protease-activated receptor-1.

    Directory of Open Access Journals (Sweden)

    Jenell R Smith

    Full Text Available Chronic neck pain is a major problem with common causes including disc herniation and spondylosis that compress the spinal nerve roots. Cervical nerve root compression in the rat produces sustained behavioral hypersensitivity, due in part to the early upregulation of pro-inflammatory cytokines, the sustained hyperexcitability of neurons in the spinal cord and degeneration in the injured nerve root. Through its activation of the protease-activated receptor-1 (PAR1, mammalian thrombin can enhance pain and inflammation; yet at lower concentrations it is also capable of transiently attenuating pain which suggests that PAR1 activation rate may affect pain maintenance. Interestingly, salmon-derived fibrin, which contains salmon thrombin, attenuates nerve root-induced pain and inflammation, but the mechanisms of action leading to its analgesia are unknown. This study evaluates the effects of salmon thrombin on nerve root-mediated pain, axonal degeneration in the root, spinal neuronal hyperexcitability and inflammation compared to its human counterpart in the context of their enzymatic capabilities towards coagulation substrates and PAR1. Salmon thrombin significantly reduces behavioral sensitivity, preserves neuronal myelination, reduces macrophage infiltration in the injured nerve root and significantly decreases spinal neuronal hyperexcitability after painful root compression in the rat; whereas human thrombin has no effect. Unlike salmon thrombin, human thrombin upregulates the transcription of IL-1β and TNF-α and the secretion of IL-6 by cortical cultures. Salmon and human thrombins cleave human fibrinogen-derived peptides and form clots with fibrinogen with similar enzymatic activities, but salmon thrombin retains a higher enzymatic activity towards coagulation substrates in the presence of antithrombin III and hirudin compared to human thrombin. Conversely, salmon thrombin activates a PAR1-derived peptide more weakly than human thrombin. These

  12. Desensitisation of protease-activated receptor-1 (PAR-1) in rat astrocytes: evidence for a novel mechanism for terminating Ca2+ signalling evoked by the tethered ligand

    Science.gov (United States)

    Ubl, Joachim J; Sergeeva, Marina; Reiser, Georg

    2000-01-01

    Protease-activated receptor-1 (PAR-1), a G-protein-coupled receptor, is activated when thrombin cleaves its N-terminal exodomain, thereby regulating morphology, growth and survival of neurones and astrocytes. We have investigated the mechanism of PAR-1 desensitisation and resensitisation after proteolytic or non-proteolytic stimulation with thrombin or thrombin receptor agonist peptide (TRag), respectively. In rat primary astrocytes, short-term stimulation with thrombin resulted in a single [Ca2+]i transient and a dose-dependent de- and resensitisation, as assessed by single-cell Ca2+ imaging of fura-2-loaded astrocytes. An initial proteolytic activation of astrocyte PAR-1 by exposure to thrombin strongly decreased the response elicited by subsequent application of a second dose of thrombin or of TRag. In contrast, after an initial non-proteolytic activation of astrocyte PAR-1 by TRag, the subsequent response to thrombin, but not to an additional application of TRag, was strongly attenuated, and the time course for desensitisation was slower. Based on this finding we hypothesised that after PAR-1 activation, the ‘tethered ligand’ is proteolytically destroyed. As a consequence, the receptor becomes unresponsive to a subsequent thrombin stimulus but is still capable of responding to TRag. This hypothesis was supported by applying thermolysin, which is known to cleave PAR-1 within its tethered-ligand domain, and was confirmed by incubation with soybean trypsin inhibitor. PAR-1 resensitisation occurs via new PAR-1 synthesis since resensitisation was inhibited by cycloheximide and brefeldin A. From these results, we derive a novel model wherein activation of PAR-1, in addition to initiating signal transduction, activates a protease mechanism that cleaves the N-terminus of the receptor, thus terminating the signal and probably inducing receptor internalisation. PMID:10835036

  13. Protease signaling through protease activated receptor 1 mediate nerve activation by mucosal supernatants from irritable bowel syndrome but not from ulcerative colitis patients.

    Science.gov (United States)

    Buhner, Sabine; Hahne, Hannes; Hartwig, Kerstin; Li, Qin; Vignali, Sheila; Ostertag, Daniela; Meng, Chen; Hörmannsperger, Gabriele; Braak, Breg; Pehl, Christian; Frieling, Thomas; Barbara, Giovanni; De Giorgio, Roberto; Demir, Ihsan Ekin; Ceyhan, Güralp Onur; Zeller, Florian; Boeckxstaens, Guy; Haller, Dirk; Kuster, Bernhard; Schemann, Michael

    2018-01-01

    The causes of gastrointestinal complaints in irritable bowel syndrome (IBS) remain poorly understood. Altered nerve function has emerged as an important pathogenic factor as IBS mucosal biopsy supernatants consistently activate enteric and sensory neurons. We investigated the neurally active molecular components of such supernatants from patients with IBS and quiescent ulcerative colitis (UC). Effects of supernatants from 7 healthy controls (HC), 20 IBS and 12 UC patients on human and guinea pig submucous neurons were studied with neuroimaging techniques. We identify differentially expressed proteins with proteome analysis. Nerve activation by IBS supernatants was prevented by the protease activated receptor 1 (PAR1) antagonist SCHE79797. UC supernatants also activated enteric neurons through protease dependent mechanisms but without PAR1 involvement. Proteome analysis of the supernatants identified 204 proteins, among them 17 proteases as differentially expressed between IBS, UC and HC. Of those the four proteases elastase 3a, chymotrypsin C, proteasome subunit type beta-2 and an unspecified isoform of complement C3 were significantly more abundant in IBS compared to HC and UC supernatants. Of eight proteases, which were upregulated in IBS, the combination of elastase 3a, cathepsin L and proteasome alpha subunit-4 showed the highest prediction accuracy of 98% to discriminate between IBS and HC groups. Elastase synergistically potentiated the effects of histamine and serotonin-the two other main neuroactive substances in the IBS supernatants. A serine protease inhibitor isolated from the probiotic Bifidobacterium longum NCC2705 (SERPINBL), known to inhibit elastase-like proteases, prevented nerve activation by IBS supernatants. Proteases in IBS and UC supernatants were responsible for nerve activation. Our data demonstrate that proteases, particularly those signalling through neuronal PAR1, are biomarker candidates for IBS, and protease profiling may be used to

  14. A Functional Interplay between Human Immunodeficiency Virus Type 1 Protease Residues 77 and 93 Involved in Differential Regulation of Precursor Autoprocessing and Mature Protease Activity.

    Directory of Open Access Journals (Sweden)

    Christopher J Counts

    Full Text Available HIV-1 protease (PR is a viral enzyme vital to the production of infectious virions. It is initially synthesized as part of the Gag-Pol polyprotein precursor in the infected cell. The free mature PR is liberated as a result of precursor autoprocessing upon virion release. We previously described a model system to examine autoprocessing in transfected mammalian cells. Here, we report that a covariance analysis of miniprecursor (p6*-PR sequences derived from drug naïve patients identified a series of amino acid pairs that vary together across independent viral isolates. These covariance pairs were used to build the first topology map of the miniprecursor that suggests high levels of interaction between the p6* peptide and the mature PR. Additionally, several PR-PR covariance pairs are located far from each other (>12 Å Cα to Cα relative to their positions in the mature PR structure. Biochemical characterization of one such covariance pair (77-93 revealed that each residue shows distinct preference for one of three alkyl amino acids (V, I, and L and that a polar or charged amino acid at either of these two positions abolishes precursor autoprocessing. The most commonly observed 77V is preferred by the most commonly observed 93I, but the 77I variant is preferred by other 93 variances (L, V, or M in supporting precursor autoprocessing. Furthermore, the 77I93V covariant enhanced precursor autoprocessing and Gag polyprotein processing but decreased the mature PR activity. Therefore, both covariance and biochemical analyses support a functional association between residues 77 and 93, which are spatially distant from each other in the mature PR structure. Our data also suggests that these covariance pairs differentially regulate precursor autoprocessing and the mature protease activity.

  15. Prophage Rs551 and Its Repressor Gene orf14 Reduce Virulence and Increase Competitive Fitness of Its Ralstonia solanacearum Carrier Strain UW551

    Directory of Open Access Journals (Sweden)

    Abdelmonim Ali Ahmad

    2017-12-01

    Full Text Available We previously characterized a filamentous lysogenic bacteriophage, ϕRs551, isolated directly from the race 3 biovar 2 phylotype IIB sequevar 1 strain UW551 of Ralstonia solanacearum grown under normal culture conditions. The genome of ϕRs551 was identified with 100% identity in the deposited genomes of 11 race 3 biovar 2 phylotype IIB sequevar 1 strains of R. solanacearum, indicating evolutionary and biological importance, and ORF14 of ϕRs551 was annotated as a putative type-2 repressor. In this study, we determined the effect of the prophage and its ORF14 on the virulence and competitive fitness of its carrier strain UW551 by deleting the orf14 gene only (the UW551 orf14 mutant, and nine of the prophage’s 14 genes including orf14 and six out of seven structural genes (the UW551 prophage mutant, respectively, from the genome of UW551. The two mutants were increased in extracellular polysaccharide production, twitching motility, expression of targeted virulence and virulence regulatory genes (pilT, egl, pehC, hrPB, and phcA, and virulence, suggesting that the virulence of UW551 was negatively regulated by ϕRs551, at least partially through ORF14. Interestingly, we found that the wt ϕRs551-carrying strain UW551 of R. solanacearum significantly outcompeted the wt strain RUN302 which lacks the prophage in tomato plants co-inoculated with the two strains. When each of the two mutant strains was co-inoculated with RUN302, however, the mutants were significantly out-competed by RUN302 for the same colonization site. Our results suggest that ecologically, ϕRs551 may play an important role by regulating the virulence of and offering a competitive fitness advantage to its carrier bacterial strain for persistence of the bacterium in the environment, which in turn prolongs the symbiotic relationship between the phage ϕRs551 and the R. solanacearum strain UW551. Our study is the first toward a better understanding of the co-existence between a

  16. Aerobic physiology of redox-engineered Saccharomyces cerevisiae strains modified in the ammonium assimilation for increased NADPH availability

    DEFF Research Database (Denmark)

    Santos, Maria Margarida M. dos; Thygesen, G.; Kotter, P.

    2003-01-01

    , and alternative pathways for ammonium assimilation were overexpressed: GDH2 (NADH-consuming) or GLN1 and GLT1 (the GS-GOGAT system). The flux through the pentose phosphate pathway during aerobic growth on glucose decreased to about half that of the reference strain Saccharomyces cerevisiae CEN.KK113-7D...

  17. Neutrophil Elastase Activates Protease-activated Receptor-2 (PAR2) and Transient Receptor Potential Vanilloid 4 (TRPV4) to Cause Inflammation and Pain.

    Science.gov (United States)

    Zhao, Peishen; Lieu, TinaMarie; Barlow, Nicholas; Sostegni, Silvia; Haerteis, Silke; Korbmacher, Christoph; Liedtke, Wolfgang; Jimenez-Vargas, Nestor N; Vanner, Stephen J; Bunnett, Nigel W

    2015-05-29

    Proteases that cleave protease-activated receptor-2 (PAR(2)) at Arg(36)↓Ser(37) reveal a tethered ligand that binds to the cleaved receptor. PAR(2) activates transient receptor potential (TRP) channels of nociceptive neurons to induce neurogenic inflammation and pain. Although proteases that cleave PAR(2) at non-canonical sites can trigger distinct signaling cascades, the functional importance of the PAR(2)-biased agonism is uncertain. We investigated whether neutrophil elastase, a biased agonist of PAR(2), causes inflammation and pain by activating PAR2 and TRP vanilloid 4 (TRPV4). Elastase cleaved human PAR(2) at Ala(66)↓Ser(67) and Ser(67)↓Val(68). Elastase stimulated PAR(2)-dependent cAMP accumulation and ERK1/2 activation, but not Ca(2+) mobilization, in KNRK cells. Elastase induced PAR(2) coupling to Gαs but not Gαq in HEK293 cells. Although elastase did not promote recruitment of G protein-coupled receptor kinase-2 (GRK(2)) or β-arrestin to PAR(2), consistent with its inability to promote receptor endocytosis, elastase did stimulate GRK6 recruitment. Elastase caused PAR(2)-dependent sensitization of TRPV4 currents in Xenopus laevis oocytes by adenylyl cyclase- and protein kinase A (PKA)-dependent mechanisms. Elastase stimulated PAR(2)-dependent cAMP formation and ERK1/2 phosphorylation, and a PAR(2)- and TRPV4-mediated influx of extracellular Ca(2+) in mouse nociceptors. Adenylyl cyclase and PKA-mediated elastase-induced activation of TRPV4 and hyperexcitability of nociceptors. Intraplantar injection of elastase to mice caused edema and mechanical hyperalgesia by PAR(2)- and TRPV4-mediated mechanisms. Thus, the elastase-biased agonism of PAR(2) causes Gαs-dependent activation of adenylyl cyclase and PKA, which activates TRPV4 and sensitizes nociceptors to cause inflammation and pain. Our results identify a novel mechanism of elastase-induced activation of TRPV4 and expand the role of PAR(2) as a mediator of protease-driven inflammation and pain.

  18. Genetic resistance to murine cryptococcosis: increased susceptibility in the CBA/N XID mutant strain of mice.

    OpenAIRE

    Marquis, G; Montplaisir, S; Pelletier, M; Mousseau, S; Auger, P

    1985-01-01

    In a survey of 301 normocomplementemic inbred mice (belonging to nine different strains: BALB/cN nu/nu and nu/+, CBA/N, C57BL/KsJ, C57BR/cdJ, CBA/CaJ, BRVR, DW/+, and C57BL/6J) for natural resistance to Cryptococcus neoformans, cumulative survival values were found to range from 12 to 22 days. When the average organ weights of infected animals were compared with reference values obtained in uninfected mice of the same age and genetic lineage, the following changes were documented. In the CBA/...

  19. Isolation of Mucorales from processed maize (Zea mays L. and screening for protease activity Isolamento de Mucorales de milho processado (Zea mays L. e seleção quanto à atividade proteásica

    Directory of Open Access Journals (Sweden)

    André Luiz Cabral Monteiro de Azevedo Santiago

    2008-12-01

    Full Text Available Mucoraleswere isolated from maize flour, corn meal and cooked cornflakes using surface and depth plate methods. Rhizopus oryzae, Circinella muscae, Mucor subtilissimus,Mucor hiemalis f. hiemalis, Syncephalastrum racemosum, Rhizopus microsporus var. chinensis and Absidia cylindrospora showed protease activity.Mucorales foram isolados da farinha de milho, fubá e flocos de milho pré-cozidos pelos métodos de plaqueamento em superfície e em profundidade. Rhizopus oryzae, Circinella muscae, Mucor subtilissimus,Mucor hiemalis f. hiemalis, Syncephalastrum racemosum, Rhizopus microsporus var. chinensis e Absidia cylindrospora exibiram atividade proteásica.

  20. Protease-activated receptor 2 (PAR2) is upregulated by Acanthamoeba plasminogen activator (aPA) and induces proinflammatory cytokine in human corneal epithelial cells.

    Science.gov (United States)

    Tripathi, Trivendra; Abdi, Mahshid; Alizadeh, Hassan

    2014-05-29

    Acanthamoeba plasminogen activator (aPA) is a serine protease elaborated by Acanthamoeba trophozoites that facilitates the invasion of trophozoites to the host and contributes to the pathogenesis of Acanthamoeba keratitis (AK). The aim of this study was to explore if aPA stimulates proinflammatory cytokine in human corneal epithelial (HCE) cells via the protease-activated receptors (PARs) pathway. Acanthamoeba castellanii trophozoites were grown in peptone-yeast extract glucose for 7 days, and the supernatants were collected and centrifuged. The aPA was purified using the fast protein liquid chromatography system, and aPA activity was determined by zymography assays. Human corneal epithelial cells were incubated with or without aPA (100 μg/mL), PAR1 agonists (thrombin, 10 μM; TRAP-6, 10 μM), and PAR2 agonists (SLIGRL-NH2, 100 μM; AC 55541, 10 μM) for 24 and 48 hours. Inhibition of PAR1 and PAR2 involved preincubating the HCE cells for 1 hour with the antagonist of PAR1 (SCH 79797, 60 μM) and PAR2 (FSLLRY-NH2, 100 μM) with or without aPA. Human corneal epithelial cells also were preincubated with PAR1 and PAR2 antagonists and then incubated with or without PAR1 agonists (thrombin and TRAP-6) and PAR2 agonists (SLIGRL-NH2 and AC 55541). Expression of PAR1 and PAR2 was examined by quantitative RT-PCR (qRT-PCR), flow cytometry, and immunocytochemistry. Interleukin-8 expression was quantified by qRT-PCR and ELISA. Human corneal epithelial cells constitutively expressed PAR1 and PAR2 mRNA. Acanthamoeba plasminogen activator and PAR2 agonists significantly upregulated PAR2 mRNA expression (1- and 2-fold, respectively) (P aPA, and PAR2 agonists induced PAR2 mRNA expression in HCE cells (P aPA, significantly upregulated PAR1 mRNA expression, which was significantly inhibited by PAR1 antagonist in HCE cells. Acanthamoeba plasminogen activator and PAR2 agonists stimulated IL-8 mRNA expression and protein production, which is significantly diminished by PAR2 antagonist

  1. THE KINETICS OF THE REACTIONS CATALYZED BY AN ENZYMATIC PREPARATION PRODUCED BY A BACILLUS LICHENIFORMIS STRAIN

    Directory of Open Access Journals (Sweden)

    MONICA DRAGOMIRESCU

    2007-05-01

    Full Text Available Robust immobilization techniques that preserve the activity of biomolecules have manypotential applications. In recent years, a number of new bioimobilisation methods in solgel-derived materials were reported. The interactions between the biomolecule and theinorganic material determine the degree to which the biomolecule retains its nativeproperties. The newer technological developments in the field of immobilizedbiocatalysts can offer the possibility of a wider and more economical exploitation ofbiocatalysts in biological applications, food and feed industry, medicine, and in thedevelopment of bioprocess monitoring devices, like the biosensors.The aim of this study was to obtain immobilized enzymatic preparations by methodswhich affect enzyme conformations and kinetic parameters as less as possible. Weimmobilized the enzymatic preparation with protease activity produced by a Bacilluslicheniformis B 40 local strain by physical bonding on ceramics and entrapment into solgel-derived glasses obtained from tetraethyl orthosilicate (TEOS, deposited in thin layeron a ceramic support (entrapment/deposition. Both physically adsorbed andentrapped/deposited enzymes follow Michaelis-Menten kinetics, similar with the solubleenzyme. In the case of immobilized enzymes, the apparent Michaelis constant, Km, wasgreater than that of the native one, as it was expected. The kinetic parameters indicatethat the enzymatic preparations adsorbed on ceramic support and entrapped/depositedshow less affinity for the substrate, Km being 1.3 and 2.1 times higher than that of thenative enzyme, respectively. The maximum velocity increased also by 3.5 and 7.9 timesrespectively, compared with the free counterpart (according to Lineweaver-Burklinearization.

  2. 'Synthetic lipase' production from a newly isolated Sporidiobolus pararoseus strain by submerged fermentation

    Directory of Open Access Journals (Sweden)

    Alessandra Smaniotto

    2012-12-01

    Full Text Available The lipase produced by a newly isolate Sporidiobolus pararoseus strain has potential catalysis ability for esterification reactions. In order to improve its synthetic activity, this work aimed at optimizing 'synthetic lipase' production by submerged fermentation of a conventional media based on peptone, yeast extract, NaCl and olive oil using experimental design technique. According to the results obtained in the first experimental design (2(4-1, yeast extract and NaCl concentrations were tested to further optimization by response surface methodology. The maximum 'synthetic lipase' activity obtained was 26.9 U/mL in the optimized media (5.0, 6.8, 7.0 and 1.0% (wt/v of peptone, yeast extract, NaCl and olive oil, respectively, representing a 6.36-fold increase compared to the initial medium. The time course of 'synthetic lipase' production in the optimized condition was evaluated in terms of synthetic activity, protease activity, biomass and total carbon and the maximum synthetic activity was observed during the stationary phase of growth.

  3. The probiotic bacterial strain Lactobacillus fermentum D3 increases in vitro the bioavailability of Ca, P, and Zn in fermented goat milk.

    Science.gov (United States)

    Bergillos-Meca, Triana; Navarro-Alarcón, Miguel; Cabrera-Vique, Carmen; Artacho, Reyes; Olalla, Manuel; Giménez, Rafael; Moreno-Montoro, Miriam; Ruiz-Bravo, Alfonso; Lasserrot, Agustín; Ruiz-López, Ma Dolores

    2013-02-01

    We determined calcium, magnesium, phosphorus and zinc levels in a total of 27 samples of commercial goat- and cow-milk fermented products and 9 samples of a goat-milk fermented product with addition of a probiotic bacterial strain, Lactobacillus fermentum D3, manufactured experimentally by our research group. Atomic absorption spectroscopy with flame atomization and UV/VIS spectrophotometry were used as analytic techniques. The results of an in vitro digestion process showed that the bioavailability of calcium, phosphorus, and zinc was significantly higher in our fermented milk containing the probiotic bacterial strain than it was in commercial goat-milk fermented products. Furthermore, our product showed a significantly higher bioavailability of calcium and zinc compared to goat- and cow-milk fermented products made with other microorganisms. We conclude that, in in vitro assays, strain D3 seems to increase the bioavailability of these minerals and that this new product may constitute a better source of bioavailable minerals compared to other products already on the market.

  4. Rapid evolution of human immunodeficiency virus strains with increased replicative capacity during the seronegative window of primary infection.

    Science.gov (United States)

    Ferbas, J; Daar, E S; Grovit-Ferbas, K; Lech, W J; Detels, R; Giorgi, J V; Kaplan, A H

    1996-01-01

    The relationship between host and virus was examined during the initial stages of human immunodeficiency virus type 1 (HIV) infection in a volunteer from the Multicenter AIDS Cohort Study (MACS). The individual was asymptomatic and unaware of his infection during an initial donation of blood and inguinal lymphoid tissue. Proviral DNA, however, was present in cells from both sources, HIV RNA was detected in the plasma, and CD4+ cell levels were reduced by approximately 50% compared with previous donations in the MACS. In a second blood donation 12 days later, plasma HIV RNA increased 200-fold in tandem with viral isolates with an increased growth phenotype in vitro. HIV burden was ultimately suppressed upon seroconversion and the emergence of HIV-specific CD8+ cytotoxic T lymphocytes. These observations provide further evidence that the potential benefits of early treatment may be maximized during the early stages of infection, when viral fitness may be low but is unopposed by immune responses. PMID:8794384

  5. Enhancement of 2,3-butanediol production from Jerusalem artichoke tuber extract by a recombinant Bacillus sp. strain BRC1 with increased inulinase activity.

    Science.gov (United States)

    Park, Jang Min; Oh, Baek-Rock; Kang, In Yeong; Heo, Sun-Yeon; Seo, Jeong-Woo; Park, Seung-Moon; Hong, Won-Kyung; Kim, Chul Ho

    2017-07-01

    A Bacillus sp. strain named BRC1 is capable of producing 2,3-butanediol (2,3-BD) using hydrolysates of the Jerusalem artichoke tuber (JAT), a rich source of the fructose polymer inulin. To enhance 2,3-BD production, we undertook an extensive analysis of the Bacillus sp. BRC1 genome, identifying a putative gene (sacC) encoding a fructan hydrolysis enzyme and characterizing the activity of the resulting recombinant protein expressed in and purified from Escherichia coli. Introduction of the sacC gene into Bacillus sp. BRC1 using an expression vector increased enzymatic activity more than twofold. Consistent with this increased enzyme expression, 2,3-BD production from JAT was also increased from 3.98 to 8.10 g L -1 . Fed-batch fermentation of the recombinant strain produced a maximal level of 2,3-BD production of 28.6 g L -1 , showing a high theoretical yield of 92.3%.

  6. Prolonged exposure of methicillin-resistant Staphylococcus aureus (MRSA) COL strain to increasing concentrations of oxacillin results in a multidrug-resistant phenotype

    DEFF Research Database (Denmark)

    Martins, Ana; Couto, Isabel; Aagaard, Lone

    2007-01-01

    Our previous studies demonstrated that exposure of a bacterium to increasing concentrations of an antibiotic would increase resistance to that antibiotic as a consequence of activating efflux pumps. This study utilises the same approach; however, it employs the methicillin-resistant Staphylococcus...... aureus (MRSA) COL strain, which is highly resistant to oxacillin (OXA). MRSA COL was adapted to 3200 mg/L of OXA. Changes in resistance to other antibiotics were evaluated and efflux pump activity during the adaptation process was determined. MRSA COL was exposed to stepwise two-fold increases of OXA....... At the end of each step, minimum inhibitory concentration determination for erythromycin (ERY) and other antibiotics was conducted. Reserpine (RES) was employed to evaluate whether resistance to ERY was dependent on efflux pump activity. Efflux pump activity was also evaluated using the ethidium bromide (EB...

  7. Study on optimum growth condition and designing formulation for increasing shelf life of Streptomyces rimosus strain C-2012 as biocontrol agent

    Directory of Open Access Journals (Sweden)

    Ebrahim Karimi

    2015-12-01

    Full Text Available Introduction: An important issue in microbial biotechnology is linkage between screened beneficial strains in laboratory and industry. Therefore, to develop beneficial microbial biocontrol agents; optimization of nutritional and physiological condition for high level production and selection of carrier for final formulation are necessary. In this research we tried to find the best growth condition and suitable formulation for biocontrol Streptomyces rimosus strain C-2012. Materials and methods: For optimization of growth condition of strain C-2012, utilization of carbon sources, growth in different media, effect of temperature, pH and NaCl were investigated. Then the effect of different carriers and additives in final formulation and shelf life of microbial community were studied. Results: Study on utilization of carbon sources showed that glucose, fructose and mannitole were suitable carbon sources for growth and the best initial pH and temperature were 7 and 28°C, respectively. Results showed that the culture medium containing glucose, yeast extract and malt extract was the best medium. Investigation on NaCl effect showed that from 0 up to 300 mM sodium chloride could increase microbial community and salinity more than this range decreased microbial community. Based on the results we found that sand is suitable as microbial carrier comparing hydrogel polymers. Viability test during 36 months showed that formulation with NaCl content could keep 200 times (8*106 cfu/g more than samples without salinity at last month. Discussion and conclusion: Using suitable carbon sources such as glucose at 28 °C and pH at 7 are important items in optimum growth and preparing final formulation with good level of microbial community. Capability in secondary volatile and liquid metabolites production and fungal pathogen control by Streptomyces rimosus in the presence of NaCl showed that this strain has high potentiality to apply in both normal and saline area

  8. Screening and characterization of alkaline protease produced by a pink pigmented facultative methylotrophic (PPFM strain, MSF 46

    Directory of Open Access Journals (Sweden)

    Shanmugam Jayashree

    2014-12-01

    Full Text Available Among the various bacterial isolates, the strain MSF 46 isolated from thorn forest soil samples, Tamil Nadu, India, was screened and characterized for its proteolytic activity. While the 16S rRNA sequencing and biochemical characterization revealed that the strain closely resembles Methylobacterium sp., methylotrophy of the strain was confirmed by the sequence homology of mxaF gene with other relative Methylobacterium sp. The alkaline protease was purified to homogeneity using DEAE cellulose ion exchange chromatography, with a 5.2-fold increase in specific activity and 34% recovery. The apparent molecular weight of the enzyme was determined as 40 kDa by SDS–PAGE study. The pH and temperature optima were 9.0 and 50 °C respectively with maximum protease activity of 1164 U/ml. Protease of MSF 46 was active in a broad pH range 7.0–11.0 with a maximum at pH 8.5 and exhibited thermostability at 50 °C. The enzyme activity was inhibited by PMSF but showed stability with Tween 20, Triton X-100 and hydrogen peroxide. Nearly 30% reduction in enzyme activity was observed in the presence of EDTA and DTT. The enzyme was effective in hydrolyzing gelatin, skimmed milk and blood clots and exhibited the potency for dehairing of goat skin and removing blood stain from cotton fabric. Significant morphological changes were observed under scanning electron microscope between cells grown in normal and casein amended medium. This first detailed report on the production of alkaline protease by a PPFM strain appears promising toward development of protocols for mass production, study of the molecular mechanism and other applications.

  9. Increased number of intestinal villous M cells in levamisole - pretreated weaned pigs experimentally infected with F4ac+ enterotoxigenic Escherichia coli strain

    Directory of Open Access Journals (Sweden)

    H. Valpotić

    2010-07-01

    Full Text Available Immunoprophylaxis of porcine postweaning colibacillosis (PWC caused by enterotoxigenic Escherichia coli (ETEC expressing F4 fimbriae is an unsolved problem. Just as ETEC strains can exploit intestinal microfold (M cells as the entry portal for infection, their high transcytotic ability make them an attractive target for mucosally delivered vaccines, adjuvants and therapeutics. We have developed a model of parenteral/oral immunization of 4-weeks-old pigs with either levamisole or vaccine candidate F4ac+ non-ETEC strain to study their effects on de novo differentiation of antigen-sampling M cells. Identification, localization and morphometric quantification of cytokeratin 18 positive M cells in the ileal mucosa of 6-weeks-old pigs revealed that they were: 1 exclusively located within villous epithelial layer, 2 significantly numerous (P< 0.01 in levamisole pretreated/challenged pigs, and 3 only slightly, but not significantly numerous in vaccinated/challenged pigs compared with non-pretreated/challenged control pigs. The fact that levamisole may affect the M cells frequency by increasing their numbers, makes it an interesting adjuvant to study development of an effective M cell-targeted vaccine against porcine PWC.

  10. Ability of an alkali-tolerant mutant strain of the microalga Chlorella sp. AT1 to capture carbon dioxide for increasing carbon dioxide utilization efficiency.

    Science.gov (United States)

    Kuo, Chiu-Mei; Lin, Tsung-Hsien; Yang, Yi-Chun; Zhang, Wen-Xin; Lai, Jinn-Tsyy; Wu, Hsi-Tien; Chang, Jo-Shu; Lin, Chih-Sheng

    2017-11-01

    An alkali-tolerant Chlorella sp. AT1 mutant strain was screened by NTG mutagenesis. The strain grew well in pH 6-11 media, and the optimal pH for growth was 10. The CO 2 utilization efficiencies of Chlorella sp. AT1 cultured with intermittent 10% CO 2 aeration for 10, 20 and 30min at 3-h intervals were approximately 80, 42 and 30%, respectively. In alkaline medium (pH=11) with intermittent 10% CO 2 aeration for 30min at 3-, 6- and 12-h intervals, the medium pH gradually changed to 10, and the biomass productivities of Chlorella sp. AT1 were 0.987, 0.848 and 0.710gL -1 d -1 , respectively. When Chlorella sp. AT1 was aerated with 10% CO 2 intermittently for 30min at 3-h intervals in semi-continuous cultivation for 21days, the biomass concentration and biomass productivity were 4.35gL -1 and 0.726gL -1 d -1 , respectively. Our results show that CO 2 utilization efficiency can be markedly increased by intermittent CO 2 aeration and alkaline media as a CO 2 -capturing strategy for alkali-tolerant microalga cultivation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Increased hepatic Th2 and Treg subsets are associated with biliary fibrosis in different strains of mice caused by Clonorchis sinensis.

    Directory of Open Access Journals (Sweden)

    Bei-Bei Zhang

    Full Text Available Previous studies showed that CD4+T cells responses might be involved in the process of biliary fibrosis. However, the underlying mechanism resulting in biliary fibrosis caused by Clonorchis sinensis remains not yet fully elucidated. The objectives of the present study were to investigate the different profiles of hepatic CD4+T cell subsets (Th1, Th2, Th17 and Treg cells and their possible roles in the biliary fibrosis of different strains of mice (C57BL/6, BALB/c and FVB mice induced by C. sinensis infection. C57BL/6, BALB/c and FVB mice were orally gavaged with 45 metacercariae. All mice were sacrificed on 28 days post infection in deep anesthesia conditions. The leukocytes in the liver were separated to examine CD4+T cell subsets by flow cytometry and the left lobe of liver was used to observe pathological changes, collagen depositions and the concentrations of hydroxyproline. The most serious cystic and fibrotic changes appeared in FVB infected mice indicated by gross observation, Masson's trichrome staining and hydroxyproline content detection. In contrast to C57BL/6 infected mice, diffuse nodules and more intensive fibrosis were observed in the BALB/c infected mice. No differences of the hepatic Th1 subset and Th17 subset were found among the three strains, but the hepatic Th2 and Treg cells and their relative cytokines were dramatically increased in the BALB/c and FVB infected groups compared with the C57BL/6 infected group (P<0.01. Importantly, increased Th2 subset and Treg subset all positively correlated with hydroxyproline contents (P<0.01. This result for the first time implied that the increased hepatic Th2 and Treg cell subsets were likely to play potential roles in the formation of biliary fibrosis in C. sinensis-infected mice.

  12. Diammonium phosphate stimulates transcription of L-lactate dehydrogenase leading to increased L-lactate production in the thermotolerant Bacillus coagulans strain.

    Science.gov (United States)

    Sun, Lifan; Li, Yanfeng; Wang, Limin; Wang, Yanping; Yu, Bo

    2016-08-01

    Exploration of cost-effective fermentation substrates for efficient lactate production is an important economic objective. Although some organic nitrogen sources are also cheaper, inorganic nitrogen salts for lactate fermentation have additional advantages in facilitating downstream procedures and significantly improving the commercial competitiveness of lactate production. In this study, we first established an application of diammonium phosphate to replace yeast extract with a reduced 90 % nitrogen cost for a thermotolerant Bacillus coagulans strain. In vivo enzymatic and transcriptional analyses demonstrated that diammonium phosphate stimulates the gene expression of L-lactate dehydrogenase, thus providing higher specific enzyme activity in vivo and increasing L-lactic acid production. This new information provides a foundation for establishing a cost-effective process for polymer-grade L-lactic acid production in an industrial setting.

  13. Increased prevalence of human cutaneous leishmaniasis in Israel and the Palestinian Authority caused by the recent emergence of a population of genetically similar strains of Leishmania tropica.

    Science.gov (United States)

    Azmi, Kifaya; Krayter, Lena; Nasereddin, Abedelmajeed; Ereqat, Suheir; Schnur, Lionel F; Al-Jawabreh, Amer; Abdeen, Ziad; Schönian, Gabriele

    2017-06-01

    Twelve unlinked microsatellite markers were used to determine the microsatellite profiles of 50 newly and 46 previously typed strains of L. tropica from various Israeli and Palestinian foci. Their microsatellite profiles were compared to those of 99 previously typed strains of L. tropica from 15 countries. Israeli and Palestinian strains of L. tropica fell into three different groups, one of which contained 75 of the 96 Israeli and Palestinian strains. This population separated from all the others at the first hierarchical level by Bayesian statistics and formed a distinct monophyletic group on applying genetic distance and allele frequency analyses. The second cluster contained ten Israeli strains from a specific focus north of the Sea of Galilee, which were previously shown to differ from all other strains of L. tropica in their serological, biochemical and molecular biological parameters. This cluster was closely related to clusters comprising strains of L. tropica from Africa. Four Israeli and five Palestinian strains fell into different genetic entities mostly related to strains from Asian foci of CL. Importation during numerous migrations of humans and, perhaps, infected reservoir animals in the past and, now, through modern travel is the most likely explanation for the existence of so many locally encountered genetic variants of L. tropica in the Israeli-Palestinian region. Geographical and ecological variation may play a role in expanding the genetic heterogeneity once given importations had become established in different foci. Currently, one population is expanding in the area comprising almost all of the Palestinian and Israeli strains of L. tropica isolated since 1996 and investigated in this study, which differ clearly from all other strains of whatsoever origin. This population seems to result from the re-emergence of a previously existing genotype owing to environmental changes and human activities. Copyright © 2016 The Author(s). Published by

  14. Brain tissue strains vary with head impact location: A possible explanation for increased concussion risk in struck versus striking football players.

    Science.gov (United States)

    Elkin, Benjamin S; Gabler, Lee F; Panzer, Matthew B; Siegmund, Gunter P

    2018-03-29

    On-field football helmet impacts over a large range of severities have caused concussions in some players but not in other players. One possible explanation for this variability is the struck player's helmet impact location. We examined the effect of impact location on regional brain tissue strain when input energy was held constant. Laboratory impacts were performed at 12 locations distributed over the helmet and the resulting head kinematics were simulated in two finite element models of the brain: the Simulated Injury Monitor and the Global Human Body Model Consortium brain model. Peak kinematics, injury metrics and brain strain varied significantly with impact location. Differences in impact location explained 33 to 37% of the total variance in brain strain for the whole brain and cerebrum, considerably more than the variance explained by impact location for the peak resultant head kinematics (8 to 23%) and slightly more than half of the variance explained by the difference in closing speed (57 to 61%). Both finite element models generated similar strain results, with minor variations for impacts that generated multi-axial rotations, larger variations in brainstem strains for some impact locations and a small bias for the cerebellum. Based on this experimental and computational simulation study, impact location on the football helmet has a large effect on regional brain tissue strain. We also found that the lowest strains consistently occurred in impacts to the crown and forehead, helmet locations commonly associated with the striking player. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Non-Saccharomyces and Saccharomyces strains co-fermentation increases acetaldehyde accumulation: effect on anthocyanin-derived pigments in Tannat red wines.

    Science.gov (United States)

    Medina, Karina; Boido, Eduardo; Fariña, Laura; Dellacassa, Eduardo; Carrau, Francisco

    2016-07-01

    During fermentation, Saccharomyces cerevisiae releases into the medium secondary metabolic products, such as acetaldehyde, able to react with anthocyanins, producing more stable derived pigments. However, very limited reports are found about non-Saccharomyces effects on grape fermentation. In this study, six non-Saccharomyces yeast strains, belonging to the genera Metschnikowia and Hanseniaspora, were screened for their effect on red wine colour and wine-making capacity under pure culture conditions and mixed with Saccharomyces. An artificial red grape must was prepared, containing a phenolic extract of Tannat grapes that allows monitoring changes of key phenol parameters during fermentation, but without skin solids in the medium. When fermented in pure cultures, S. cerevisiae produced higher concentrations of acetaldehyde and vitisin B (acetaldehyde reaction-dependent) compared to M. pulcherrima M00/09G, Hanseniaspora guillermondii T06/09G, H. opuntiae T06/01G, H. vineae T02/05F and H. clermontiae (A10/82Fand C10/54F). However, co-fermentation of H. vineae and H. clermontiae with S. cerevisiae resulted in a significantly higher concentration of acetaldehyde compared with the pure S. cerevisiae control. HPLC-DAD-MS analysis confirmed an increased formation of vitisin B in co-fermentation treatments when compared to pure Saccharomyces fermentation, suggesting the key role of acetaldehyde. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Increased replication of T-cell-tropic HIV strains and CXC-chemokine receptor-4 induction in T cells treated with macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and RANTES beta-chemokines.

    Science.gov (United States)

    Dolei, A; Biolchini, A; Serra, C; Curreli, S; Gomes, E; Dianzani, F

    1998-01-22

    To study, in T-lymphoid cells, the effects of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and RANTES beta-chemokines on the replication of T-cell-tropic HIV-1 strains, since it has been reported that beta-chemokines interfere with the replication of macrophage-tropic HIV-1 strains, but not T-cell-tropic strains. Freshly phytohaemagglutinin (PHA)-activated peripheral blood lymphocytes (PBL) and cultured PHA-activated T cells from healthy volunteers, as well as the C8166 T-cell line, were treated overnight with beta-chemokines before infection with T-cell-tropic HIV-1 isolates, or human T-lymphotropic virus type IIIB. HIV replication was followed by detecting the production of infectious particles, p24 antigen, and viral sequences. CXC-chemokine receptor (CXCR)-4 expression was followed by detection and quantification of specific transcripts. Pretreatment of T cells with MIP-1alpha, MIP-1beta and RANTES affected T-cell-tropic strains, increased the replication of HIV-1beta and HIV-1RPdT strains dose-dependently, as well as virus absorption and provirus DNA accumulation. These findings were associated with increased accumulation of CXCR-4 transcripts, and mediated by the protein tyrosine kinase signalling. Moreover, beta-chemokines stimulated PBL proliferation. Beta-chemokines increase the adsorption and replication of at least some T-cell-tropic HIV-1 strains, and this is related to stimulated expression of the CXCR-4 coreceptor.

  17. Effect of poloxamer 407 administration on the serum lipids profile, anxiety level and protease activity in the heart and liver of mice

    Science.gov (United States)

    Johnston, Thomas P.; Dubrovina, Nina I.; Kisarova, Yana A.; Zhanaeva, Svetlana Ya.; Cherkanova, Marina S.; Filjushina, Elena E.; Alexeenko, Tatyana V.; Machova, Eva; Zhukova, Natalya A.

    2013-01-01

    Chronic administration of the poloxamer 407 (P-407), a block copolymer, to elevate serum lipids in mice is a well-established mouse model of hyperlipidemia and atherosclerosis. We tested the hypothesis that the activity of several types of proteases in heart and liver tissue is changed in the early stages of atherosclerosis development. Additionally, we evaluated whether increased serum lipids would induce anxiety in mice, as determined by using a ‘plus-maze’ test. The mice were administered P-407 by intraperitoneal injection twice a week for one month. P-407 administration to mice resulted in a marked increase in total serum cholesterol, atherogenic non-HDL-cholesterol, and especially in total triglycerides, and it also increased anxiety. Morphological changes observed in P-407-treated mice included contractile type changes in cardiomyocytes and foamy macrophages in liver. A significant increase of cysteine proteases cathepsin B and cathepsin L (at 24 h) and aspartate protease cathepsin D (at both 24 h and 5 days) was determined in heart tissue following P-407 administration. However, no changes were noted in heart matrix metalloproteinase activity. The activity of cysteine and aspartate proteases was significantly increased in liver at both 24 hours and 5 days after P-407 administration. In conclusion, administration of P-407 to mice for one month resulted in increased anxiety, and more importantly, there was an increase in the activity of heart and liver proteases secondary to sustained dyslipidemia. It is suggested that heart and liver cysteine and aspartate proteases may represent potential therapeutic targets in the early stages of atherosclerosis. PMID:24170975

  18. Purification and characterization of a halophilic α-amylase with increased activity in the presence of organic solvents from the moderately halophilic Nesterenkonia sp. strain F.

    Science.gov (United States)

    Shafiei, Mohammad; Ziaee, Abed-Ali; Amoozegar, Mohammad Ali

    2012-07-01

    An extracellular halophilic α-amylase was purified from Nesterenkonia sp. strain F using 80 % ethanol precipitation and Q-Sepharose anion exchange chromatography. The enzyme showed a single band with an apparent molecular weight of 110 kDa by SDS-PAGE. The amylase exhibited maximal activity at pH 7-7.5, being relatively stable at pH 6.5-7.5. Optimal temperature for the amylase activity and stability was 45 °C. The purified enzyme was highly active in the broad range of NaCl concentrations (0-4 M) with optimal activity at 0.25 M NaCl. The amylase was highly stable in the presence of 3-4 M NaCl. Amylase activity was not influenced by Ca²⁺, Rb⁺, Li⁺, Cs⁺, Mg²⁺ and Hg²⁺, whereas Fe³⁺, Cu²⁺, Zn²⁺ and Al³⁺) strongly inhibited the enzyme activity. The α-amylase was inhibited by EDTA, but was not inhibited by PMSF and β-mercaptoethanol. K(m) value of the amylase for soluble starch was 6.6 mg/ml. Amylolytic activity of the enzyme was enhanced not only by 20 % of water-immiscible organic solvents but also by acetone, ethanol and chloroform. Higher concentration (50 %) of the water-miscible organic solvents had no significant effect on the amylase activity. To the best of our knowledge, this is the first report on increased activity of a microbial α-amylase in the presence of organic solvents.

  19. Chow fed UC Davis strain female Lepr fatty Zucker rats exhibit mild glucose intolerance, hypertriglyceridemia, and increased urine volume, all reduced by a Brown Norway strain chromosome 1 congenic donor region.

    Directory of Open Access Journals (Sweden)

    Craig H Warden

    Full Text Available Our objective is to identify genes that influence the development of any phenotypes of type 2 diabetes (T2D or kidney disease in obese animals. We use the reproductively isolated UC Davis fatty Zucker strain rat model in which the defective chromosome 4 leptin receptor (LeprfaSte/faSte results in fatty obesity. We previously produced a congenic strain with the distal half of chromosome 1 from the Brown Norway strain (BN on a Zucker (ZUC background (BN.ZUC-D1Rat183-D1Rat90. Previously published studies in males showed that the BN congenic donor region protects from some phenotypes of renal dysfunction and T2D. We now expand our studies to include females and expand phenotyping to gene expression. We performed diabetes and kidney disease phenotyping in chow-fed females of the BN.ZUC-D1Rat183-D1Rat90 congenic strain to determine the specific characteristics of the UC Davis model. Fatty LeprfaSte/faSte animals of both BN and ZUC genotype in the congenic donor region had prediabetic levels of fasting blood glucose and blood glucose 2 hours after a glucose tolerance test. We observed significant congenic strain chromosome 1 genotype effects of the BN donor region in fatty females that resulted in decreased food intake, urine volume, glucose area under the curve during glucose tolerance test, plasma triglyceride levels, and urine glucose excretion per day. In fatty females, there were significant congenic strain BN genotype effects on non-fasted plasma urea nitrogen, triglyceride, and creatinine. Congenic region genotype effects were observed by quantitative PCR of mRNA from the kidney for six genes, all located in the chromosome 1 BN donor region, with potential effects on T2D or kidney function. The results are consistent with the hypothesis that the BN genotype chromosome 1 congenic region influences traits of both type 2 diabetes and kidney function in fatty UC Davis ZUC females and that there are many positional candidate genes.

  20. Response surface methodology for production, characterization and application of solvent, salt and alkali-tolerant alkaline protease from isolated fungal strain Aspergillus niger WA 2017.

    Science.gov (United States)

    Abdel Wahab, Walaa A; Ahmed, Samia A

    2018-04-17

    Isolated strain Aspergillus niger WA 2017 was selected as potential protease producer and was identified on the basis of 18S rDNA gene homology. Optimization of protease production conditions was performed using statistical methodology. The most significant factors were identified by Plackett-Burman design (PB) and were optimized by central composite design (CCD). The enzyme production was increased by 3.6-fold with statistically optimized medium when compared to the basal medium. Based on the protease activity, 25-50% ethanol fraction exhibited the highest specific activity. The partially purified enzyme showed its highest activity (4.7-fold) after 10 min incubation at pH 10.0 and 60 °C. The enzyme was stable over a wide range of pH (7-11) and salt concentration (up to 20%). Kinetic parameters Michaelis constant (K m ) and maximum velocity (V max ) were calculated at varying casein concentrations. Additionally, thermal stability of the enzyme was substantially improved by NaCl. The enzyme showed excellent stability and compatibility in presence of organic solvents and detergents retaining 115.3 and 114.5% of its activity in presence of ethanol and Tide, respectively at 40 °C for 1 h. The results revealed that the produced enzyme was able to recover silver from used X-ray film under optimized condition using statistical methodology (CCD). Copyright © 2017. Published by Elsevier B.V.

  1. Effect of poloxamer 407 administration on the serum lipids profile, anxiety level and protease activity in the heart and liver of mice

    OpenAIRE

    Korolenko, Tatyana A.; Johnston, Thomas P.; Dubrovina, Nina I.; Kisarova, Yana A.; Zhanaeva, Svetlana Ya.; Cherkanova, Marina S.; Filjushina, Elena E.; Alexeenko, Tatyana V.; Machova, Eva; Zhukova, Natalya A.

    2013-01-01

    Chronic administration of the poloxamer 407 (P-407), a block copolymer, to elevate serum lipids in mice is a well-established mouse model of hyperlipidemia and atherosclerosis. We tested the hypothesis that the activity of several types of proteases in heart and liver tissue is changed in the early stages of atherosclerosis development. Additionally, we evaluated whether increased serum lipids would induce anxiety in mice, as determined by using a ?plus-maze? test. The mice were administered ...

  2. Development of a Markerless Genetic Exchange System in Desulfovibrio vulgaris Hildenborough and Its Use in Generating a Strain with Increased Transformation Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Kimberly L.; Bender, Kelly S.; Wall, Judy D.

    2009-07-21

    In recent years, the genetic manipulation of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough has seen enormous progress. In spite of this progress, the current marker exchange deletion method does not allow for easy selection of multiple sequential gene deletions in a single strain because of the limited number of selectable markers available in D. vulgaris. To broaden the repertoire of genetic tools for manipulation, an in-frame, markerless deletion system has been developed. The counterselectable marker that makes this deletion system possible is the pyrimidine salvage enzyme, uracil phosphoribosyltransferase, encoded by upp. In wild-type D. vulgaris, growth was shown to be inhibited by the toxic pyrimidine analog 5-fluorouracil (5-FU); whereas, a mutant bearing a deletion of the upp gene was resistant to 5-FU. When a plasmid containing the wild-type upp gene expressed constitutively from the aph(3')-II promoter (promoter for the kanamycin resistance gene in Tn5) was introduced into the upp deletion strain, sensitivity to 5-FU was restored. This observation allowed us to develop a two-step integration and excision strategy for the deletion of genes of interest. Since this inframe deletion strategy does not retain an antibiotic cassette, multiple deletions can be generated in a single strain without the accumulation of genes conferring antibiotic resistances. We used this strategy to generate a deletion strain lacking the endonuclease (hsdR, DVU1703) of a type I restriction-modification system, that we designated JW7035. The transformation efficiency of the JW7035 strain was found to be 100 to 1000 times greater than that of the wild-type strain when stable plasmids were introduced via electroporation.

  3. Increasing antimicrobial resistance of Vibrio cholerae OI biotype E1 tor strains isolated in a tertiary-care centre in India.

    Science.gov (United States)

    Mandal, Jharna; Dinoop, K P; Parija, Subhash Chandra

    2012-03-01

    The antimicrobial susceptibility patterns are on constant change with the recent emergence of multidrug-resistant strains of most bacteria. Results of recent studies in India showed that most isolates of Vibrio cholerae O1 were resistant to the commonly-used antibiotics. The study was conducted to determine the antibiotic susceptibility patterns of V. cholerae O1 isolated during 2008-2010 at the hospital of the Jawaharlal Nehru Institute of Post Graduate Medical Education and Research, Puducherry, India. In total, 154 strains of V. cholerae O1 from 2,658 stool specimens were reported during January 2008-December 2010--34 in 2008, 2 in 2009, and 118 in 2010. The isolates of V. cholerae O1 were subjected to antimicrobial susceptibility testing using the Kirby-Bauer method. The antibiotic disks tested were tetracycline (30 microg), furazolidone (100 microg), ampicillin (10 microg), ceftriaxone (30 microg), and ciprofloxacin (5 microg). Escherichia coli ATCC 25922 was used as the control organism. The minimum inhibitory concentrations (MICs) of ceftriaxone, ciprofloxacin, and tetracycline were determined using the agar dilution method for all the strains. The E-test method was used for the strains which had either intermediate resistance or were resistant to the antibiotics by the agar dilution method. The results of the agar dilution corroborated the results of the E-test. The MIC of ceftriaxone in 151 strains was resistant to ceftriaxone by the disc-diffusion test. The MIC of ciprofloxacin in 150 strains was 32 microg/mL, and the MIC of ciprofloxacin was >8 microg/mL. These four strains were resistant to both tetracycline and ciprofloxacin by the disc-diffusion test and were exclusive of the three ceftriaxone-resistant strains. The majority of the isolates were obtained from children aged 0-5 year(s)-70.3% (83 of 118) and 41.2% (14 of 34) were reported in 2010 and 2008 respectively. Since treating severe cases of cholera with antibiotics is important, the continuing

  4. Characterization of Nomuraea rileyi strains using polymorphic DNA, virulence and enzyme activity

    Directory of Open Access Journals (Sweden)

    Vargas Lúcia Rosane Bertholdo

    2003-01-01

    Full Text Available The characterization of entomopathogenic microorganisms is important for the selection of more effective strains for use in integrated pest-control programs. Five Nomuraea rileyi strains (SA86101, GU87401, SR86151, CG128 and VA9101 were characterized using random amplified polymorphic DNA (RAPD analysis, virulence studies and assessment of chitinolytic and proteolytic activity. RAPD analysis divided the strains into two groups with a similarity coefficient of 0,76%, group 1 consisting of strains SA86101, GU87401 and SR86151 and group 2 of strains CG128 and VA9101. The LT50 varied from 165h with strain VA9101 to 246h with strain GU87401. Chitinolytic and proteolytic activity of the fungi after 144h growth in minimal medium were tested using colloidal chitin as substrate. All strains exhibited enzyme activity, with strain VA9101 having the highest chitinase activity (0,0040 mumol/mL/min the 40ºC and strain SA86101 the highest proteolytic activity. No relationship was found between RAPD analysis, virulence and chitinase or protease activity.

  5. Cathepsin B- and L-like cysteine protease activities during the in vitro development of Hysterothylacium aduncum (Nematoda: Anisakidae), a worldwide fish parasite.

    Science.gov (United States)

    Malagón, David; Díaz-López, Manuel; Benítez, Rocío; Adroher, Francisco Javier

    2010-03-01

    Proteinases play an important role as virulence factors both in the life-cycle of parasites and in the pathogen-host relationship. Hysterothylacium aduncum is a worldwide fish parasite nematode which has been associated with non-invasive anisakidosis and allergic responses to fish consumption in humans. Cysteine proteinases have been associated with allergy to plant pollens, detergents and dust mites. In this study the presence of two types of cysteine proteinases (cathepsin B and cathepsin L) during in vitro development of H. aduncum is investigated. Specific fluorescent substrates were used to determine cathepsin activities. The activity detected with substrate Z-FR-AMC was identified as cathepsin L (optimum pH=5.5; range 3.5-6.5). Cathepsin B activity was only identified with Z-RR-AMC (optimum pH=7.0-7.5; range 5.0-8.0). The start of cultivation led to increased activity of both cathepsins (1.8-fold for cathepsin B and 6.3-fold for cathepsin L). These activities varied according to the developmental stage. Cathepsin B activity decreased after M4, returning to its initial level. Cathepsin L activity also decreased after M4, but still maintained a high level (4-6 times the initial level) in adult stages. Having considered these activity variations and the optimum pH values, we suggest that cathepsin L has a role in digestive processes while cathepsin B could be involved in cuticle renewal, among other possible functions. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  6. Molecular and Phenotypic Characterization of Metschnikowia pulcherrima Strains from Douro Wine Region

    Directory of Open Access Journals (Sweden)

    Catarina Barbosa

    2018-01-01

    Full Text Available Some non-Saccharomyces yeasts, including Metschnikowia pulcherrima, have been proposed as selected starters due to their contribution for the overall aroma and chemical profiles of wines. In this work, we aimed to evaluate the genetic and phenotypic diversity of Metschnikowia pulcherrima strains isolated from different locations of Douro Wine Region, and to explore their potential as co-adjuncts of S. cerevisiae in alcoholic fermentation. For that purpose, a set of 64 M. pulcherrima isolates were used. Polymerase chain reaction (PCR fingerprinting with M13 primers demonstrated to be an efficient tool in intraspecific discrimination of M. pulcherrima strains. No significant associations were found between genotypic profiles and either geographical origin or winery. The isolates were screened for their stress resistance ability (ethanol, SO2, chitosan, copper, H2O2, and Grape Juice Medium, aroma-related activities (resistance to 5, 5′, 5′′-trifluor-d, l-leucine and cerulenin and β-glycosidase, β-lyase and sulfite-reductase activities as well as other relevant technological proprieties (protease activity and biogenic amines production. M. pulcherrima response to the different enological traits evaluated was greatly strain-dependent. The most discriminant features were the ability of the strains to grow in Grape-Juice Medium (GJM and sulfite-reductase, and their β-lyase and protease activities. The enological potential of a selected M. pulcherrima strain in mixed-culture with S. cerevisiae was also assessed in natural grape-juice of a local variety, under two nitrogen regimes. M. pulcherrima proved to be promising for future industrial application as a co-starter, lowering ethanol, acetic acid and, reported here for the first time, lowering hydrogen sulfide levels in the wines.

  7. Protease-activated quantum dot probes

    International Nuclear Information System (INIS)

    Chang, Emmanuel; Miller, Jordan S.; Sun, Jiantang; Yu, William W.; Colvin, Vicki L.; Drezek, Rebekah; West, Jennifer L.

    2005-01-01

    We have developed a novel nanoparticulate luminescent probe with inherent signal amplification upon interaction with a targeted proteolytic enzyme. This construct may be useful for imaging in cancer detection and diagnosis. In this system, quantum dots (QDs) are bound to gold nanoparticles (AuNPs) via a proteolytically degradable peptide sequence to non-radiatively suppress luminescence. A 71% reduction in luminescence was achieved with conjugation of AuNPs to QDs. Release of AuNPs by peptide cleavage restores radiative QD photoluminescence. Initial studies observed a 52% rise in luminescence over 47 h of exposure to 0.2 mg/mL collagenase. These probes can be customized for targeted degradation simply by changing the sequence of the peptide linker

  8. Helicobacter pylori strains harboring babA2 from Indian sub population are associated with increased virulence in ex vivo study

    OpenAIRE

    Ghosh, Prachetash; Sarkar, Avijit; Ganguly, Mou; Raghwan,; Alam, Jawed; De, Ronita; Mukhopadhyay, Asish K.

    2016-01-01

    Background The babA2 gene along with the cagA and vacA of Helicobacter pylori has been considered as a risk factor for the disease outcome in certain populations. This study was aimed to understand the role of babA2 of H. pylori with the background of cagA and vacA in disease manifestations in Indian sub population. Methods A total of 114 H. pylori strains isolated from duodenal ulcer (DU) (n?=?53) and non-ulcer dyspepsia (NUD) patients (n?=?61) were screened for the prevalence of these virul...

  9. Regulator of G protein signaling 2 (RGS2 and RGS4 form distinct G protein-dependent complexes with protease activated-receptor 1 (PAR1 in live cells.

    Directory of Open Access Journals (Sweden)

    Sungho Ghil

    Full Text Available Protease-activated receptor 1 (PAR1 is a G-protein coupled receptor (GPCR that is activated by natural proteases to regulate many physiological actions. We previously reported that PAR1 couples to Gi, Gq and G12 to activate linked signaling pathways. Regulators of G protein signaling (RGS proteins serve as GTPase activating proteins to inhibit GPCR/G protein signaling. Some RGS proteins interact directly with certain GPCRs to modulate their signals, though cellular mechanisms dictating selective RGS/GPCR coupling are poorly understood. Here, using bioluminescence resonance energy transfer (BRET, we tested whether RGS2 and RGS4 bind to PAR1 in live COS-7 cells to regulate PAR1/Gα-mediated signaling. We report that PAR1 selectively interacts with either RGS2 or RGS4 in a G protein-dependent manner. Very little BRET activity is observed between PAR1-Venus (PAR1-Ven and either RGS2-Luciferase (RGS2-Luc or RGS4-Luc in the absence of Gα. However, in the presence of specific Gα subunits, BRET activity was markedly enhanced between PAR1-RGS2 by Gαq/11, and PAR1-RGS4 by Gαo, but not by other Gα subunits. Gαq/11-YFP/RGS2-Luc BRET activity is promoted by PAR1 and is markedly enhanced by agonist (TFLLR stimulation. However, PAR1-Ven/RGS-Luc BRET activity was blocked by a PAR1 mutant (R205A that eliminates PAR1-Gq/11 coupling. The purified intracellular third loop of PAR1 binds directly to purified His-RGS2 or His-RGS4. In cells, RGS2 and RGS4 inhibited PAR1/Gα-mediated calcium and MAPK/ERK signaling, respectively, but not RhoA signaling. Our findings indicate that RGS2 and RGS4 interact directly with PAR1 in Gα-dependent manner to modulate PAR1/Gα-mediated signaling, and highlight a cellular mechanism for selective GPCR/G protein/RGS coupling.

  10. Increased risk for Campylobacter jejuni and C. coli infection of pet origin in dog owners and evidence for genetic association between strains causing infection in humans and their pets.

    Science.gov (United States)

    Mughini Gras, L; Smid, J H; Wagenaar, J A; Koene, M G J; Havelaar, A H; Friesema, I H M; French, N P; Flemming, C; Galson, J D; Graziani, C; Busani, L; VAN Pelt, W

    2013-12-01

    We compared Campylobacter jejuni/coli multilocus sequence types (STs) from pets (dogs/cats) and their owners and investigated risk factors for pet-associated human campylobacteriosis using a combined source-attribution and case-control analysis. In total, 132/687 pet stools were Campylobacter-positive, resulting in 499 strains isolated (320 C. upsaliensis/helveticus, 100 C. jejuni, 33 C. hyointestinalis/fetus, 10 C. lari, 4 C. coli, 32 unidentified). There were 737 human and 104 pet C. jejuni/coli strains assigned to 154 and 49 STs, respectively. Dog, particularly puppy, owners were at increased risk of infection with pet-associated STs. In 2/68 cases vs. 0.134/68 expected by chance, a pet and its owner were infected with an identical ST (ST45, ST658). Although common sources of infection and directionality of transmission between pets and humans were unknown, dog ownership significantly increased the risk for pet-associated human C. jejuni/coli infection and isolation of identical strains in humans and their pets occurred significantly more often than expected.

  11. Increased A:T-->C:G mutations in the mutT strain upon 8-hydroxy-dGTP treatment: direct evidence for MutT involvement in the prevention of mutations by oxidized dGTP.

    Science.gov (United States)

    Kamiya, Hiroyuki; Ishiguro, Chieko; Harashima, Hideyoshi

    2004-09-01

    The Escherichia coli MutT protein hydrolyzes 8-hydroxy-dGTP (8-OH-dGTP) in vitro, and mutT gene deficiencies cause increased spontaneous A:T-->C:G mutations. However, no direct evidence exists for enhanced mutagenicity of 8-OH-dGTP in mutT cells. In this study, 8-OH-dGTP was introduced into wild type and mutT E. coli cells, and mutations of a chromosomal gene were monitored. 8-OH-dGTP induced mutations of the rpoB gene, the degree of the mutation induction in the mutT strain being approximately 6-fold higher than that in the wild type strain. On the other hand, 2-hydroxy-dATP, which is not a substrate of the MutT protein, increased the mutation to similar degrees in the two strains. These results constitute the first evidence that the MutT protein suppresses mutation by 8-OH-dGTP in vivo.

  12. LAOS: The strain softening/strain hardening paradox

    NARCIS (Netherlands)

    Mermet-Guyennet, M.R.B.; de Castro, J.G.; Habibi, M.; Martzel, N.; Denn, M.M.; Bonn, D.

    2015-01-01

    Numerous materials, from biopolymers to filled rubbers, exhibit strain softening at high strain amplitudes during a strain sweep in oscillatory rheology: The modulus decreases with increasing deformation. On the other hand, if the nonlinear elastic response is analyzed within a single oscillation

  13. STAT3 polymorphism and Helicobacter pylori CagA strains with higher number of EPIYA-C segments independently increase the risk of gastric cancer

    International Nuclear Information System (INIS)

    Rocha, Gifone A; Rocha, Andreia MC; Gomes, Adriana D; Faria, César LL Jr; Melo, Fabrício F; Batista, Sérgio A; Fernandes, Viviane C; Almeida, Nathálie BF; Teixeira, Kádima N; Brito, Kátia S; Queiroz, Dulciene Maria Magalhães

    2015-01-01

    Because to date there is no available study on STAT3 polymorphism and gastric cancer in Western populations and taking into account that Helicobacter pylori CagA EPIYA-C segment deregulates SHP-2/ERK-JAK/STAT3 pathways, we evaluated whether the two variables are independently associated with gastric cancer. We included 1048 subjects: H. pylori-positive patients with gastric carcinoma (n = 232) and with gastritis (n = 275) and 541 blood donors. Data were analyzed using logistic regression model. The rs744166 polymorphic G allele (p = 0.01; OR = 1.76; 95 % CI = 1.44-2.70), and CagA-positive (OR = 12.80; 95 % CI = 5.58-19.86) status were independently associated with gastric cancer in comparison with blood donors. The rs744166 polymorphism (p = 0.001; OR = 1.64; 95 % CI = 1.16-2.31) and infection with H. pylori CagA-positive strains possessing higher number of EPIYA-C segments (p = 0.001; OR = 2.28; 95 % CI = 1.41-3.68) were independently associated with gastric cancer in comparison with gastritis. The association was stronger when host and bacterium genotypes were combined (p < 0.001; OR = 3.01; 95 % CI = 2.29-3.98). When stimulated with LPS (lipopolysaccharide) or Pam3Cys, peripheral mononuclear cells of healthy carriers of the rs744166 GG and AG genotypes expressed higher levels of STAT3 mRNA than those carrying AA genotype (p = 0.04 for both). The nuclear expression of phosphorylated p-STAT3 protein was significantly higher in the antral gastric tissue of carriers of rs744166 GG genotype than in carriers of AG and AA genotypes. Our study provides evidence that STAT3 rs744166 G allele and infection with CagA-positive H. pylori with higher number of EPIYA-C segments are independent risk factors for gastric cancer. The odds ratio of having gastric cancer was greater when bacterium and host high risk genotypes were combined

  14. Expression of dehydrin gene from Arctic Cerastium arcticum increases abiotic stress tolerance and enhances the fermentation capacity of a genetically engineered Saccharomyces cerevisiae laboratory strain.

    Science.gov (United States)

    Kim, Il-Sup; Kim, Hyun-Young; Kim, Young-Saeng; Choi, Han-Gu; Kang, Sung-Ho; Yoon, Ho-Sung

    2013-10-01

    We investigated Arctic plants to determine if they have a specific mechanism enabling them to adapt to extreme environments because they are subject to such conditions throughout their life cycles. Among the cell defense systems of the Arctic mouse-ear chickweed Cerastium arcticum, we identified a stress-responsive dehydrin gene CaDHN that belongs to the SK5 subclass and contains conserved regions with one S segment at the N-terminus and five K segments from the N-terminus to the C-terminus. To investigate the molecular properties of CaDHN, the yeast Saccharomyces was transformed with CaDHN. CaDHN-expressing transgenic yeast (TG) cells recovered more rapidly from challenge with exogenous stimuli, including oxidants (hydrogen peroxide, menadione, and tert-butyl hydroperoxide), high salinity, freezing and thawing, and metal (Zn(2+)), than wild-type (WT) cells. TG cells were sensitive to copper, cobalt, and sodium dodecyl sulfate. In addition, the cell survival of TG cells was higher than that of WT cells when cells at the mid-log and stationary stages were exposed to increased ethanol concentrations. There was a significant difference in cultures that have an ethanol content >16 %. During glucose-based batch fermentation at generally used (30 °C) and low (18 °C) temperatures, TG cells produced a higher alcohol concentration through improved cell survival. Specifically, the final alcohol concentrations were 13.3 and 13.2 % in TG cells during fermentation at 30 and 18 °C, respectively, whereas they were 10.2 and 9.4 %, respectively, in WT cells under the same fermentation conditions. An in vitro assay revealed that purified CaDHN acted as a reactive oxygen species scavenger by neutralizing H2O2 and a chaperone by preventing high temperature-mediated catalase inactivation. Taken together, our results show that CaDHN expression in transgenic yeast confers tolerance to various abiotic stresses by improving redox homeostasis and enhances fermentation capacity

  15. An attemp at reversibility and increase of the virulence of axenic strains of Entamoeba histolytica Tentativa de reversibilidade e aumento de virulência de cepas axônicas de Entamoeba histolytica

    Directory of Open Access Journals (Sweden)

    Maria Aparecida Gomes

    1993-12-01

    Full Text Available In this study we have tried to verify whether the interaction "in vitro" with bacteria or small pieces of normal hamster liver would modify the pathogenic behavior of axenic strains of E. histolytica: avirulent ones (ICB-32 and ICB-RPS, of attenuated virulence (ICB-CSP and HM1 and of mean virulence (ICB-462. Every attempt to render virulent, recover or increase the virulence of axenic strains of E. histolytica has failedNeste trabalho procuramos verificar se a interação "in vitro" com bactérias e fragmentos de fígado de hamster normal, modificaria o comportamento patogênico de cepas axênicas de E. histolytica avirulentas (ICB-32 e ICB-RPS; virulentas, porém atenuadas (ICB-CSP e HM1 e de média virulência (ICB-462. Todas as tentativas de tornar virulentas, restabelecer ou aumentar a virulência das cepas axênicas de E. histolytica utilizadas fracassaram

  16. Dimerization of the type IV pilin from Pseudomonas aeruginosa strain K122-4 results in increased helix stability as measured by time-resolved hydrogen-deuterium exchange

    Directory of Open Access Journals (Sweden)

    Cristina Lento

    2016-01-01

    Full Text Available Truncated pilin monomers from Pseudomonas aeruginosa strain K122-4 (ΔK122 have been shown to enter a monomer-dimer equilibrium in solution prior to oligomerization into protein nanotubes. Here, we examine the structural changes occurring between the monomeric and dimeric states of ΔK122 using time-resolved hydrogen-deuterium exchange mass spectrometry. Based on levels of deuterium uptake, the N-terminal α-helix and the loop connecting the second and third strands of the anti-parallel β-sheet contribute significantly to pilin dimerization. Conversely, the antiparallel β-sheet and αβ loop region exhibit increased flexibility, while the receptor binding domain retains a rigid conformation in the equilibrium state.

  17. Phenotypic characterization and adhesive properties of vaginal Candida spp. strains provided by the CHU Farhat Hached (Sousse, Tunisia).

    Science.gov (United States)

    Noumi, Emira; Snoussi, Mejdi; Noumi, Inès; Saghrouni, Fatma; Aouni, Mahjoub; Valentin, Eulogio

    2015-01-01

    Vulvovaginal candidiasis is a common infection among women worldwide, being Candida albicans the most commonly isolated species. Therefore, controlling this opportunistic yeast is one of the key factors for reducing nosocomial infection. We investigated several virulence properties of 28 vaginal strains of Candida isolated from Tunisian women suffering from vulvovaginitis. We also analyzed the virulence properties of a clinical Candida krusei strain and five Candida reference strains. Candida strains were subjected to microscopic analysis and culture in Candida ID2 chromogenic medium. The adhesive properties of these strains were estimated by the microtiter plate - the safranin-staining - and the Congo red agar (CRA) methods, for determining yeast ability to form biofilms on biomaterials used in urinary catheter manufacturing. Their potency to produce hydrolytic enzymes was also studied. Our results showed that nine out of the total studied strains produced phospholipase. In addition, very high protease activity was detected in 23 Candida strains. All Candida strains were beta-hemolytic and adhered to polystyrene microtiter plates in varying degrees. Two vaginal C. albicans strains were strongly adhesive to polystyrene and glass slides. Also, our results showed that vaginal Candida strains were more adhesive to the three tested materials than the reference strains. This study shows the presence of a range of virulence and adhesion factors in clinical isolates of vaginal Candida. Consequently, control and treatment of vaginal candidiasis as a means to prevent biofilm formation on urinary catheters is of crucial importance. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  18. Effect of strain rate and temperature at high strains on fatigue behavior of SAP alloys

    DEFF Research Database (Denmark)

    Blucher, J.T.; Knudsen, Per; Grant, N.J.

    1968-01-01

    Fatigue behavior of three SAP alloys of two nominal compositions (7 and 13% Al2O3) was studied in terms of strain rate and temperature at high strains; strain rate had no effect on life at 80 F, but had increasingly greater effect with increasing temperature above 500 F; life decreased with decre......Fatigue behavior of three SAP alloys of two nominal compositions (7 and 13% Al2O3) was studied in terms of strain rate and temperature at high strains; strain rate had no effect on life at 80 F, but had increasingly greater effect with increasing temperature above 500 F; life decreased...

  19. Human immunodeficiency virus type 1 Brazilian subtype B variant showed an increasing avidity of the anti-V3 antibodies over time compared to the subtype B US/European strain in São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Casseb Jorge

    2004-01-01

    Full Text Available The Brazilian variant of human immunodeficiency virus type 1 (HIV-1 subtype B, (serotype B"-GWGR, has a tryptophan replacing the proline in position 328 the HIV-1 envelope. A longer median time period from infection to acquired immunodeficiency syndrome (AIDS for serotype B (B"-GWGR infected subjects compared to the B-GPGR US/European strain was reported. In a cohort study, in São Paulo city, 10 B"-GWGR patients had a statistically significant increased avidity of the anti-V3 antibodies, from 79% ± 33% to 85% ± 75%, versus from 48% ± 59% to 32% ± 17% for the 10 B-GPGR subjects (p = 0.02. The T CD4+ cells showed a mean increase of + 0.45 cells/month for the B-GPGR subjects and for B"-GWGR the slope was + 1.24 cells/month (p = 0.06, for 62 and 55 months of follow up, respectively. RNA plasma viral load decreased from 3.98 ± 1.75 to 2.16 ± 1.54 log10 in the B"-GWGR group while B-GPGR patients showed one log10 reduction in viral load from 4.09 ± 0.38 to 3.17 ± 1.47 log10 over time (p = 0.23, with a decreasing slope of 0.0042 ± log10,/month and 0.0080 ± log10/month, for B-GPGR and B"-GWGR patients, respectively (p = 0.53. Neither group presented any AIDS defining events during the study, according to Center for Diseases Control criteria. Although the sample size is small, these results may indicate that differences in the pathogenicity of the 2 HIV-1 B serotypes which co-circulate in Brazil may be correlated to the avidity of anti-V3 antibodies.

  20. THE EFFECT OF BETA GLUCAN OF SACCHAROMYCES CEREVISAE ON THE INCREASE OF THE NUMBER OF BRAIN CELLS IN SUBSTANTIA NIGRA BRAIN OF PARKINSON’S WISTAR STRAIN RAT (RATTUS NORVEGICUS MODEL INDUCED WITH ROTENONE

    Directory of Open Access Journals (Sweden)

    Masruroh Rahayu

    2015-01-01

    the number of brain cells in the substantia nigra of the brain of Parkinson’s Strain Wistar rat model significantly. The maximum increase in the number of brain cells is found after given the Saccharomyces cerevisae with the dose of 72mg/kgBB.

  1. Mutations in the Histone-like Nucleoid Structuring Regulatory Gene (hns) Decrease the Adherence of Shiga Toxin-producing Escherichia coli 091:H21 Strain B2F1 to Human Colonic Epithelial Cells and Increase the Production of Hemolysin

    Science.gov (United States)

    1999-10-19

    MacConkey media (SMAC) is used extensively to isolate 0157 from patient stool samples and differentiate these organisms from other fecal E. coli that...strains were routinely cultured in Luria-Bertani (LB) broth or agar (Difco Laboratories, Detroit, Mich), or on MacConkey agar (Difco), or M-9 minimal...grown on Maloney media and were not auxotrophic since they grew well on minimal M9 media Strains 34.3, 34.7 and 30.1Oa grew well on MacConkey media and

  2. The increased severity in patients presenting to hospital with diarrhea in Dhaka, Bangladesh since the emergence of the hybrid strain of Vibrio cholerae O1 is not unique to cholera patients.

    Science.gov (United States)

    Chowdhury, Fahima; Kuchta, Alison; Khan, Ashraful Islam; Faruque, A S G; Calderwood, Stephen B; Ryan, Edward T; Qadri, Firdausi

    2015-11-01

    A hybrid strain of Vibrio cholerae O1 El Tor that expresses a classical cholera toxin (CT) emerged in 2001. This hybrid variant rapidly replaced the previous El Tor strain around the world. The global emergence of this variant coincided with anecdotal reports that cholera patients were presenting with more severe dehydration and disease in many locations. A comparison was made of the severity of disease before and after the emergence of the hybrid strain in cholera patients attending an icddr,b hospital in Dhaka, Bangladesh. It was found that cholera patients presented with more severe dehydration and severe disease in the later period. However, this was also true for all non-cholera patients as well. In addition, in sub-analyses of patients who presented with rotavirus and enterotoxigenic Escherichia coli (ETEC), similar results were found. Comparing the two periods for differences in patient characteristics, nutritional status, vaccination status, and income, no plausible cause for patients presenting with more severe disease was identified in the later period. As a shift in severity for both cholera and non-cholera was observed, these results indicate that the altered El Tor strain cannot fully explain the difference in cholera severity before and after 2001. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Serum concentrations of free and total insulin-like growth factor-I, IGF binding proteins -1 and -3 and IGFBP-3 protease activity in boys with normal or precocious puberty

    DEFF Research Database (Denmark)

    Juul, A; Flyvbjerg, Allan; Frystyk, Jan

    1996-01-01

    Circulating IGF-I and IGF binding protein-3 (IGFBP-3) levels both increase in puberty where growth velocity is high. The amount of free IGF-I is dependent on the IGF-I level and on the concentrations of the specific IGFBPs. Furthermore, IGFBP-3 proteolysis regulates the bioavailability of IGF......-I. However, the concentration of free IGF-I and possible IGFBP-3 proteolytic activity in puberty has not previously been studied....

  4. Evaluation of early nodulation and Nitrogen fixation a number of Bradyrhizobium Japonicum strains to increase nitrogen fixation ability of soybean cultivars ars by using the A-value (N-15) method

    International Nuclear Information System (INIS)

    Piervali-Bieranvand, N.; Teimori, S.; Khorasani, A.

    2004-01-01

    To date significant contribution of atmospheric N fixation to soybean nutrition and growth, is approved. Nevertheless several studies have demonstrated that effectiveness of soybean -rhizobium symbiosis is medium compared with other legumes. The time course study of biological nitrogen fixation in soybean under field conditions has been shown that soybean has limited initial fixation and fixes substantially atmospheric nitrogen just during the reproductive periods (R1 until R 5).So there is the possibility of enhancing nitrogen fixation in soybean during vegetation growth. This could be done by improving inoculation methods or breeding for early nodulation. Hence, the present study was conducted to examine the effect of some Bradyrhizobium japonicum strains on early nodulation and biological nitrogen fixation three soybean cultivars by using a-value method. The experiment, was a factorial on randomized complete block design with three replications under proper glass house condition. Treatments were harvesting times(one , two and three weeks after flowering, respectively.)soybean cultivars(Chippewa, M 112 and clay )and Bradyrhizobium japonicum strains(J 1, J 3 and J 43). Ninety-plastic pots were filled with 1.5 kg of a compound of sand and soil(1:3). Rhizobial inoculation was performed by mixing 10 ml of a suspension(Yeast extract Manitol Broth) containing about 9X10 8 cells per ml to the soil of mixing pots were kept weed-free and watered with demineralized water as well as have received every two weeks 5 ml of a solution containing all the necessary nutrients except nitrogen. For measuring biological nitrogen fixation using a-value approach, two solutions of N-15 enriched ammonium sulfate containing 10.16 and %2 N-15 atom excess in amount of 5 and 25 mg N/Kg soil were mixed with soils in each pot containing fixing and reference plants, respectively. A non-nodulation isoline of soybean C v. M 129 for the all cultivars was used as a reference crop. First harvest was

  5. Hamstring strain - aftercare

    Science.gov (United States)

    Pulled hamstring muscle; Sprain - hamstring ... There are 3 levels of hamstring strains: Grade 1 -- mild muscle strain or pull Grade 2 -- partial muscle tear Grade 3 -- complete muscle tear Recovery time depends ...

  6. The Zinc-Dependent Protease Activity of the Botulinum Neurotoxins

    Science.gov (United States)

    Lebeda, Frank J.; Cer, Regina Z.; Mudunuri, Uma; Stephens, Robert; Singh, Bal Ram; Adler, Michael

    2010-01-01

    The botulinum neurotoxins (BoNT, serotypes A-G) are some of the most toxic proteins known and are the causative agents of botulism. Following exposure, the neurotoxin binds and enters peripheral cholinergic nerve endings and specifically and selectively cleaves one or more SNARE proteins to produce flaccid paralysis. This review centers on the kinetics of the Zn-dependent proteolytic activities of these neurotoxins, and briefly describes inhibitors, activators and factors underlying persistence of toxin action. Some of the structural, enzymatic and inhibitor data that are discussed here are available at the botulinum neurotoxin resource, BotDB (http://botdb.abcc.ncifcrf.gov). PMID:22069621

  7. Obturator internus muscle strains

    Directory of Open Access Journals (Sweden)

    Caoimhe Byrne, MB BCh, BAO

    2017-03-01

    Full Text Available We report 2 cases of obturator internus muscle strains. The injuries occurred in young male athletes involved in kicking sports. Case 1 details an acute obturator internus muscle strain with associated adductor longus strain. Case 2 details an overuse injury of the bilateral obturator internus muscles. In each case, magnetic resonance imaging played a crucial role in accurate diagnosis.

  8. Simulation and Analysis of Strain Sensitivity of CNT-Based Strain Sensors

    Science.gov (United States)

    Sapra, Gaurav; Vig, Renu; Sharma, Manu

    2016-10-01

    Carbon nanotubes (CNT) is turning out to be a replacement to all the existing traditional sensors due to their high gauge factor, multidirectional sensing capability, high flexibility, low mass density, high dynamic range and high sensitivity to strains at nano and macro- scales. The strain sensitivity of CNT-based strain sensors depends on number of parameters; quality and quantity of CNT used, type of polymer used, deposition and dispersion technique adopted and also on environmental conditions. Due to all these parameters, the piezoresistive behavior of CNT is diversified and it needs to be explored. This paper theoretically analyses the strain sensitivity of CNT-based strain sensors. The strain sensitivity response of CNT strain sensor is a result of change in total resistance of CNT network with respect to applied strain. The total resistance of CNT network consists of intrinsic resistance and inter-tube resistance. It has been found that the change in intrinsic resistance under strain is due to the variation of bandgap of individual, which depends on the chirality of the tube and it varies exponentially with strain. The inter-tube resistance of CNT network changes nonlinearly due to change in distance between neighboring CNTs with respect to applied strain. As the distance d between CNTs increases due to applied strain, tunneling resistance Rtunnel increases nonlinearly in exponential manner. When the concentration of CNTs in composite is close to percolation threshold, then the change of inter-tube resistances is more dominant than intrinsic resistance. At percolation threshold, the total resistance of CNT networks changes nonlinearly and this effect of nonlinearity is due to tunneling effect. The strain sensitivity of CNT-based strain sensors also varies nonlinearly with the change in temperature. For the change of temperature from -20∘C to 50∘C, there is more than 100% change in strain sensitivity of CNT/polymer composite strain sensor. This change is

  9. Characterization of a novel protease from Aeribacillus pallidus strain VP3 with potential biotechnological interest.

    Science.gov (United States)

    Mechri, Sondes; Ben Elhoul Berrouina, Mouna; Omrane Benmrad, Maroua; Zaraî Jaouadi, Nadia; Rekik, Hatem; Moujehed, Emna; Chebbi, Alif; Sayadi, Sami; Chamkha, Mohamed; Bejar, Samir; Jaouadi, Bassem

    2017-01-01

    The present study investigates the purification and physico-chemical characterization of an extracellular protease from the Aeribacillus pallidus strain VP3 previously isolated from a geothermal oil-field (Sfax, Tunisia). The maximum protease activity recorded after 22h of incubation at 45°C was 3000U/ml. Pure enzyme, designated as SPVP, was obtained after ammonium sulfate fractionation (40-60%)-dialysis followed by heat-treatment (70°C for 30min) and UNO Q-6 FPLC anion-exchange chromatography. The purified enzyme is a monomer of molecular mass about 29kDa. The sequence of the 25 NH 2 -terminal residues of SPVP showed a high homology with those of Bacillus proteases. The almost complete inhibition by PMSF and DIFP confirmed that SPVP is a member of serine protease family. Its optima of pH and temperature were pH 10 and 60°C, respectively. Its half-life times at 70 and 80°C were 8 and 4h, respectively. Its catalytic efficiency was higher than those of SAPCG, Alcalase Ultra 2.5L, and Thermolysin type X. SPVP exhibited excellent stability to detergents and wash performance analysis revealed that it could remove blood-stains effectively and high resistance against organic solvents. These properties make SPVP a potential candidate for applications in detergent formulations and non-aqueous peptide biocatalysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. A strain gauge

    DEFF Research Database (Denmark)

    2016-01-01

    The invention relates to a strain gauge of a carrier layer and a meandering measurement grid positioned on the carrier layer, wherein the strain gauge comprises two reinforcement members positioned on the carrier layer at opposite ends of the measurement grid in the axial direction....... The reinforcement members are each placed within a certain axial distance to the measurement grid with the axial distance being equal to or smaller than a factor times the grid spacing. The invention further relates to a multi-axial strain gauge such as a bi-axial strain gauge or a strain gauge rosette where each...... of the strain gauges comprises reinforcement members. The invention further relates to a method for manufacturing a strain gauge as mentioned above....

  11. Production and some properties of crude alkaline proteases of indigenous Central Amazonian rhizobia strains

    Directory of Open Access Journals (Sweden)

    Arlem Nascimento de Oliveira

    2010-10-01

    Full Text Available Two rhizobia strains isolated from soils of the Central Amazonian floodplain produced appreciable quantities of crude alkaline protease extracts with inexpensive carbon and nitrogen sources. These protease crude extracts were optimally active at pH 9.0-11.0. The optimum temperatures were 35 ºC for Rhizobium sp. strain R-986 and 55 ºC for Bradyrhizobium sp. strain R-993. Protease activities in the crude extracts were enhanced in the presence of 5 mM metal ions, such as Na+, Ca2+, Mg2+ and Mn2+. Rhizobia proteases were strongly inhibited by PMSF, a serine-protease inhibitor. The enzymes were active in the presence of surfactants (SDS and Triton X-100 and stable in oxidizing (H2O2 and reducing agents (β-mercaptoethanol, and organic solvents (acetone, hexane, methanol, 1-propanol and toluene.Duas estirpes de rizóbia isoladas de solos de várzea da Amazônia Central produziram grandes quantidades de proteases alcalinas extracelulares, usando fontes baratas de carbono e nitrogênio. Os extratos brutos de proteases foram ativos em pH 9,0-11,0. As temperaturas ótimas foram de 35 ºC para a enzima do Rhizobium R-986 e de 55 ºC para a do Bradyrhizobium R-993. As atividades proteolíticas aumentaram na presença de 5 mM dos íons Na+, Ca2+ , Mg2+ e Mn2+ . As proteases secretadas pelos rizóbios foram fortemente inibidas por PMSF, um inibidor de serina protease. As enzimas foram ativas na presença de surfactantes (SDS e Triton X-100, e estáveis na presença de agentes oxidantes (H2O2 e redutores (β-mercaptoetanol e solventes orgânicos (acetona, hexano, metanol, 1-propanol e tolueno.

  12. On fracture in finite strain gradient plasticity

    DEFF Research Database (Denmark)

    Martínez Pañeda, Emilio; Niordson, Christian Frithiof

    2016-01-01

    predictions. These differences increase significantly when large strains are taken into account, as a consequence of the contribution of strain gradients to the work hardening of the material. The magnitude of stress elevation at the crack tip and the distance ahead of the crack where GNDs significantly alter......In this work a general framework for damage and fracture assessment including the effect of strain gradients is provided. Both mechanism-based and phenomenological strain gradient plasticity (SGP) theories are implemented numerically using finite deformation theory and crack tip fields...

  13. Job strain and the risk of stroke

    DEFF Research Database (Denmark)

    Fransson, Eleonor I; Nyberg, Solja T; Heikkilä, Katriina

    2015-01-01

    studies to investigate the association between job strain, a measure of work-related stress, and incident stroke. RESULTS: In 1.8 million person-years at risk (mean follow-up 9.2 years), 2023 first-time stroke events were recorded. The age- and sex-adjusted hazard ratio for job strain relative to no job....... CONCLUSION: Job strain may be associated with an increased risk of ischemic stroke, but further research is needed to determine whether interventions targeting job strain would reduce stroke risk beyond existing preventive strategies....

  14. Studies on a novel serine protease of a ΔhapAΔprtV Vibrio cholerae O1 strain and its role in hemorrhagic response in the rabbit ileal loop model.

    Directory of Open Access Journals (Sweden)

    Aurelia Syngkon

    Full Text Available BACKGROUND: Two well-characterized proteases secreted by Vibrio cholerae O1 strains are hemagglutinin protease (HAP and V. cholerae protease (PrtV. The hapA and prtV knock out mutant, V. cholerae O1 strain CHA6.8ΔprtV, still retains residual protease activity. We initiated this study to characterize the protease present in CHA6.8ΔprtV strain and study its role in pathogenesis in rabbit ileal loop model (RIL. METHODOLOGY/PRINCIPAL FINDINGS: We partially purified the residual protease secreted by strain CHA6.8ΔprtV from culture supernatant by anion-exchange chromatography. The major protein band in native PAGE was identified by MS peptide mapping and sequence analysis showed homology with a 59-kDa trypsin-like serine protease encoded by VC1649. The protease activity was partially inhibited by 25 mM PMSF and 10 mM EDTA and completely inhibited by EDTA and PMSF together. RIL assay with culture supernatants of strains C6709 (FA ratio 1.1+/-0.3 n = 3, CHA6.8 (FA ratio 1.08+/-0.2 n = 3, CHA6.8ΔprtV (FA ratio 1.02+/-0.2 n = 3 and partially purified serine protease from CHA6.8ΔprtV (FA ratio 1.2+/-0.3 n = 3 induced fluid accumulation and histopathological studies on rabbit ileum showed destruction of the villus structure with hemorrhage in all layers of the mucosa. RIL assay with culture supernatant of CHA6.8ΔprtVΔVC1649 strain (FA ratio 0.11+/-0.005 n = 3 and with protease incubated with PMSF and EDTA (FA ratio 0.3+/-0.05 n = 3 induced a significantly reduced FA ratio with almost complete normal villus structure. CONCLUSION: Our results show the presence of a novel 59-kDa serine protease in a ΔhapAΔprtV V. cholerae O1 strain and its role in hemorrhagic response in RIL model.

  15. Strain-engineered MOSFETs

    CERN Document Server

    Maiti, CK

    2012-01-01

    Currently strain engineering is the main technique used to enhance the performance of advanced silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Written from an engineering application standpoint, Strain-Engineered MOSFETs introduces promising strain techniques to fabricate strain-engineered MOSFETs and to methods to assess the applications of these techniques. The book provides the background and physical insight needed to understand new and future developments in the modeling and design of n- and p-MOSFETs at nanoscale. This book focuses on recent developments in st

  16. Strain specificity and simultaneous transmission of closely related strains of a Potyvirus by Myzus persicae.

    Science.gov (United States)

    Srinivasan, Rajagopalbabu; Hall, Darren G; Cervantes, Felix A; Alvarez, Juan M; Whitworth, Jonathan L

    2012-06-01

    Potato virus Y (PVY), a Potyvirus, is transmitted by aphids in a nonpersistent manner. PVY severely affects potato production worldwide. Single and mixed infections of PVY strains, namely PVY(O), PVY(NTN), and PVY(N:O) are a common occurrence in potato systems. However, information available on the ability of aphids to simultaneously transmit multiple PVY strains, specificity associated with simultaneous transmission, and factors affecting specificity are limited. Aphid-mediated transmission experiments were conducted to test the ability of individual aphids to transmit multiple strains using a PVY indicator host. Preliminary results revealed that aphids can transmit at least two viral strains simultaneously. Subsequently, aphid-mediated transmission of three dual-strain combinations was tested using potato plants. Individual aphids transmitted two viral strains simultaneously for all three dual-strain combinations. In all aphid-mediated dual-strain infections involving PVY(NTN), the rate of PVY(NTN) infection was greater than the infection rates of the second strain and dual-strain combinations, indicating specificity associated with transmission of PVY strains. Results of aphid-mediated transmission experiments were compared with results obtained through mechanical transmission. In general, PVY infection rates from aphid-mediated transmission were lower than the rates obtained through mechanical transmission. Unlike aphid-mediated transmission, component strains in dual-strain inoculations were not eliminated during mechanical transmission. These results suggest that there may also be interference associated with aphid-mediated transmission of closely related PVY strains. Perhaps, the observed specificity and/or interference may explain the increase in the incidence of PVY(NTN) and other necrotic strains in recent years.

  17. A NEW STRAIN OF TRANSMISSIBLE LEUCEMIA IN FOWLS (STRAIN H).

    Science.gov (United States)

    Ellermann, V

    1921-03-31

    1. A new strain of fowl leucosis has been transmitted through twelve generations of fowls. 2. An increase in virulence was observed during its passage. This was shown in a shortening of the interval between inoculation and death. The increase in virulence does not affect the number of successful inoculations, which remains approximately constant in from 20 to 40 per cent of the birds employed. 3. As with former strains, the disease manifests itself in various forms; i.e., myeloid and intravascular lymphoid types. A single lymphatic case was observed. 4. In several intravascular cases a diminution in the hemolytic power of the serum was established. This phenomenon was absent in a number of myeloid cases. 5. Active immunization cannot be produced by means of the subcutaneous injection of virulent material. 6. The finding of previous experiments that the virus is filterable has been confirmed. 7. The inoculation of human leucemic material into fowls gave negative results.

  18. Material approaches to stretchable strain sensors.

    Science.gov (United States)

    Park, Jaeyoon; You, Insang; Shin, Sangbaie; Jeong, Unyong

    2015-04-27

    With the recent progress made in wearable electronics, devices now require high flexibility and stretchability up to large strain levels (typically larger than 30 % strain). Wearable strain sensors or deformable strain sensors have been gaining increasing research interest because of the rapid development of electronic skins and robotics and because of their biomedical applications. Conventional brittle strain sensors made of metals and piezoresistors are not applicable for such stretchable sensors. This Review summarizes recent advances in stretchable sensors and focuses on material aspects for high stretchability and sensitivity. It begins with a brief introduction to the Wheatstone bridge circuit of conventional resistive strain sensors. Then, studies on the manipulation of materials are reviewed, including waved structural approaches for making metals and semiconductors stretchable, the use of liquid metals, and conductive filler/elastomer composites by using percolation among the fillers. For capacitive strain sensors, the constant conductivity of the electrode is a key factor in obtaining reliable sensors. Possible approaches to developing capacitive strain sensors are presented. This Review concludes with a discussion on the major challenges and perspectives related to stretchable strain sensors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. A strain gauge

    DEFF Research Database (Denmark)

    2017-01-01

    The invention relates to a strain gauge of a carrier layer and a meandering measurement grid (101) positioned on the carrier layer, wherein the measurement grid comprises a number of measurement grid sections placed side by side with gaps in between, and a number of end loops (106) interconnecting...... relates to a method for manufacturing a strain gauge as mentioned above....

  20. Hole doped Dirac states in silicene by biaxial tensile strain

    KAUST Repository

    Kaloni, Thaneshwor P.

    2013-03-11

    The effects of biaxial tensile strain on the structure, electronic states, and mechanical properties of silicene are studied by ab-initio calculations. Our results show that up to 5% strain the Dirac cone remains essentially at the Fermi level, while higher strain induces hole doped Dirac states because of weakened Si–Si bonds. We demonstrate that the silicene lattice is stable up to 17% strain. It is noted that the buckling first decreases with the strain (up to 10%) and then increases again, which is accompanied by a band gap variation. We also calculate the Grüneisen parameter and demonstrate a strain dependence similar to that of graphene.

  1. Characterization of halo-alkaline and thermostable protease from Halorubrum ezzemoulense strain ETR14 isolated from Sfax solar saltern in Tunisia.

    Science.gov (United States)

    Dammak, Donyez Frikha; Smaoui, Salma Masmoudi; Ghanmi, Fadoua; Boujelben, Ines; Maalej, Sami

    2016-04-01

    A total of 54 halophilic strains were isolated from crystallizer TS18 (26 strains) and non-crystallizer M1 (28 strains) ponds and screened for their ability to produce protease, amylase, and lipase activities. Enzymatic assays allowed the selection of thirty-two active strains, among them, the ETR14 strain from TS18 showed maximum protease production yields and therefore, selected for further analysis. The results from 16S rRNA gene sequence analysis revealed that the strain belonged to Halorubrum ezzemoulense (Hrr. ezzemoulense) species. Further results indicated that optimum growth and protease production yields were obtained with 10-15% NaCl concentrations in the DSC-97 medium. The enzyme was also able to maintain high levels of protease activity at salt concentrations of up to 25%. While readily available carbon sources were noted to significantly reduce protease production, the combination between yeast extract and peptone enhanced protease excretion, which reached a maximum of 284 U ml(-1) at the end of the exponential growth phase. The enzyme exhibited optimum activity at pH 9 and 60 °C. The halophilic protease retained 87% of its initial activity after 1 h incubation at 70 °C and showed high stability over a wide range of pH, ranging from 7 to 10. This protease exhibited good temperature, pH, and salinity tolerance, which distinguishes it from other proteases previously described from other members of the holoarchaea genera and makes it a promising candidate for application in various industries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Variation in the strain anisotropy of Zircaloy with temperature and strain

    International Nuclear Information System (INIS)

    Hindle, E.D.; Worswick, D.

    1984-04-01

    Strain anisotropy was investigated at temperatures in the range 293 to 1117K in circular tensile specimens prepared from rolled Zircaloy-2 plate so that their tensile axes were parallel to and transverse to the rolling direction. The strain anisotropy factor for both types of specimen increased markedly in the high alpha phase region above 923K reaching a maximum at circa 1070K. Above this temperature in the alpha-plus-beta phase region the strain anisotropy decreased rapidly as the proportion of beta phase increased and was almost non-existent at 1173K. The strain anisotropy was markedly strain dependent, particularly in the high alpha phase region. The study was extended to Zircaloy-4 pressurized water reactor (PWR) 17 x 17 type fuel rod tubing specimens which were strained under biaxial conditions using cooling conditions which promoted uniform diametral strain over most of their lengths (circa 250 mm). In these circumstances the strain anisotropy is manifest by a reduction in length. Measurement of this change along with that in diameter and wall thickness produced data from which the strain anisotropy factor was calculated. The results, although influenced by additional factors discussed in the paper, were similar to those observed in the uniaxial Zircaloy-2 tensile tests. (author)

  3. Low cycle fatigue behavior of the extruded AZ80 magnesium alloy under different strain amplitudes and strain rates

    Directory of Open Access Journals (Sweden)

    Cong Wang

    2016-09-01

    Full Text Available Low cycle fatigue behavior of extruded AZ80 magnesium alloy was investigated under uniaxial tension-compression at different strain amplitudes and strain rates. The results show that the extruded AZ80 magnesium alloy exhibits cyclic hardening at strain amplitudes ranging from 0.4% to 1.0%, the asymmetry of hysteresis loops becomes increasingly obvious when the strain amplitude increases. Higher strain rates correspond to higher stress amplitudes, high mean stresses and short fatigue life. {10–12} extension twins play a role in the cyclic deformation under higher strain amplitudes (0.8%, 1.0%. The relationship between total strain energy density and fatigue life can be described by the modified Morrow model. The effect of strain rate on the fatigue life can also be predicted by the model.

  4. Photothermal strain imaging

    Science.gov (United States)

    Choi, Changhoon; Ahn, Joongho; Jeon, Seungwan; Kim, Chulhong

    2017-07-01

    Vulnerable plaques are the major cause of cardiovascular disease, but they are difficult to detect with conventional intravascular imaging techniques. Techniques are needed to identify plaque vulnerability based on the presence of lipids in plaque. Thermal strain imaging (TSI) is an imaging technique based on ultrasound (US) wave propagation speed, which varies with the medium temperature. In TSI, the strain that occurs during tissue temperature change can be used for lipid detection because it has a different tendency depending on the type of tissue. Here, we demonstrate photothermal strain imaging (pTSI) using an intravascular ultrasound catheter. pTSI is performed by slightly and selectively heating lipid using a relatively inexpensive continuous laser source. We applied a speckle-tracking algorithm to US B-mode images for strain calculations. As a result, the strain produced in porcine fat was different from the strain produced in water-bearing gelatin phantom, which made it possible to distinguish the two. This suggests that pTSI could potentially be a way of differentiating lipids in coronary artery.

  5. Aspartic protease from Aspergillus (Eurotium) repens strain MK82 is involved in the hydrolysis and decolourisation of dried bonito (Katsuobushi).

    Science.gov (United States)

    Aoki, Kenji; Matsubara, Sayaka; Umeda, Mayo; Tachibanac, Shusaku; Doi, Mikiharu; Takenaka, Shinji

    2013-04-01

    Katsuobushi is a dried, smoked and fermented bonito used in Japanese cuisine. During the fermentation process with several Aspergillus species, the colour of Katsuobushi gradually changes from a dark reddish-brown derived from haem proteins to pale pink. The change in colour gives Katsuobushi a higher ranking and price. This study aimed to elucidate the mechanism of decolourisation of Katsuobushi. A decolourising factor from the culture supernatant of Aspergillus (Eurotium) repens strain MK82 was purified to homogeneity. The purification was monitored by measuring the decolourising activity using equine myoglobin and bovine haemoglobin as substrates. It was found that the decolourising factor had protease activity towards myoglobin and haemoglobin. Complete inhibition of the enzyme by the inhibitor pepstatin A and the internal amino acid sequence classified the protein as an aspartic protease. The enzyme limitedly hydrolysed myoglobin between 1-Met and 2-Gly, 43-Lys and 44-Phe, and 70-Leu and 71-Thr. The purified enzyme decolourised blood of Katsuwonus pelamis (bonito) and a slice of dried bonito. It is proposed that aspartic protease plays a role in the decolourisation of Katsuobushi by the hydrolysis of haem proteins that allows the released haem to aggregate in the dried bonito. © 2012 Society of Chemical Industry.

  6. Strain: Fact or Fiction?

    Science.gov (United States)

    Heilbronner, Renée

    2017-04-01

    2017 marks the 50th anniversary of the publication of John Ramsay's well known textbook "Folding and Fracturing of Rocks" - ... and the 30th anniversary of the rejection of a rather less well known paper entitled "Strain: Fact or Fiction?" submitted by Renée Panozzo to the Journal of Structural Geology. The gist of the paper was simple and straight forward: it was argued that not every fabric that can be observed in deformed rocks is necessarily a measure of the amount of strain the rock incurred. A distinction was made between a general "fabric", i.e., the traceable geometry of grain boundaries, for example, and a so-called "strain fabric", i.e., the model geometry that would result from homogeneously straining an initially isotropic fabric and that would exhibit at least orthorhombic symmetry. To verify if a given fabric was indeed a strain fabric it was therefore suggested to use the SURFOR method (published by Panozzo) and to carry out a so-called strain test, i.e., a check of symmetry, before interpreting the results of a fabric analysis in terms of strain. The problem with the paper was that it was very obviously written out of frustration. The frustration came form having reviewed a number of manuscripts which tried to use the then novel SURFOR method for strain analysis without first checking if the the fabric was a indeed a "strain fabric" or not, and then blaming the SURFOR method for producing ambiguous results. As a result, the paper was not exactly well balanced and carefully thought out. It was considered "interesting but not scholarly" by one of the reviewers and down-right offensive by the second. To tell the truth, however, the paper was not formally rejected. The editor Sue Treagus strongly encouraged Panozzo to revise the paper, ... and 30 years later, I will follow her advise and offer a revised paper as a tribute to John Ramsay. To quote from the original manuscript: "We should be a little more impressed that strain works so well, and less

  7. Strain superlattices in graphene

    Science.gov (United States)

    Zhang, Yingjie; Kim, Youngseok; Lyding, Joseph; Gilbert, Matthew; Mason, Nadya

    Superlattices have been widely explored to tailor the electronic properties of two-dimensional electron systems. Previous approaches to create superlattices have been limited to periodic potential modulations, either in the form of electrostatic gating or moiré heterostructures. Here we present a new strategy to generate superlattices in 2D materials. We deposit these 2D membranes on a periodic array of dielectric nanospheres, and achieve superlattices with periodic strain modulations. We studied the electronic and magneto-transport properties of strained graphene superlattices, and observed salient features of Dirac point cloning and Hofstadter's butterfly. Furthermore, we were able to tune the transport properties by changing the magnitude of strain in the graphene superlattice. This new degree of freedom provides a novel platform both for fundamental studies of 2D electron correlations and for prospective applications in 2D electronic devices. Y.Z. and N.M. acknowledge support from the National Science Foundation under Grant No. ENG-1434147.

  8. Strain and temperature measurement

    International Nuclear Information System (INIS)

    Stewart, P.A.E.; Fowler, P.H.

    1988-01-01

    A method of non-invasively measuring strain and temperature of an object, substantially simultaneously, using neutrons of selected energy levels is described. A pulsed neutron source is made to emit thermal and epithermal neutrons in a collimated beam directed at the object. Temperature is monitored by observing the thermal Doppler broadening of resonances in the neutron transmission characteristic for the epithermal neutrons and strain is measured from observations made of changes to the thermal neutron diffraction pattern. The object may be a gas turbine blade or a thrust bearing. (author)

  9. Comparison of cell-specific activity between free-living and attached bacteria using isolates and natural assemblages

    DEFF Research Database (Denmark)

    Grossart, H.P.; Tang, K.W.; Kiørboe, Thomas

    2007-01-01

    Marine snow aggregates are microbial hotspots that support high bacterial abundance and activities. We conducted laboratory experiments to compare cell-specific bacterial protein production (BPP) and protease activity between free-living and attached bacteria. Natural bacterial assemblages attached...... bacteria increasing their metabolism upon attachment to surfaces. In subsequent experiments, we used four strains of marine snow bacteria isolates to test the hypothesis that bacteria could up- and down-regulate their metabolism while on and off an aggregate. The protease activity of attached bacteria...

  10. Anterior Cruciate Ligament Strain In Vivo

    Science.gov (United States)

    Luque-Seron, Juan Antonio; Medina-Porqueres, Ivan

    2016-01-01

    Context: Distinct exercises have been proposed for knee rehabilitation after anterior cruciate ligament (ACL) reconstruction. There is a need to understand ACL strain behavior during different rehabilitation exercises to protect the graft from excessive strain that could interfere with its healing process. Objective: To critically review studies that directly measured normal ACL strain in vivo during different movements, conditions, or exercises to gain insight into which of them may produce more strain on the ligament or the ligament graft in the case of reconstructed knees. Data Sources: A literature search of PubMed, CINAHL, SPORTDiscus, and PEDro databases was conducted. Keywords included anterior cruciate ligament, strain, stress, deformation, transducer, rehabilitation, rehabilitation exercise, physical therapy, and physiotherapy. Study Selection: Inclusion criteria were (1) peer-reviewed studies published in English or Spanish, (2) research conducted on adult human subjects with normal ACLs and healthy knees, and (3) ACL strain directly measured during different movements, conditions, or exercises by using a transducer. Study Design: Systematic review. Level of Evidence: Level 4. Data Extraction: Specific data were abstracted from the selected studies, including isometric quadriceps and hamstrings activity, active and passive flexion-extension of the knee, closed kinetic chain exercises, and application of joint compressive load. Results: A total of 10 studies met all criteria and were included in the final analysis. The strain values produced by closed kinetic chain and open kinetic chain exercises were similar. However, closed kinetic chain exercises appear to attenuate the strain increase that occurs in open kinetic chain exercises when increasing resistance. Conclusion: These data may be relevant to develop rehabilitation exercises or programs that do not endanger the healing ACL graft and to provide a basis for future clinical trials. PMID:27418161

  11. Plastic strain caused by contraction of pores in polycrystalline graphites

    International Nuclear Information System (INIS)

    Ioka, Ikuo; Yoda, Shinichi; Konishi, Takashi.

    1989-01-01

    The effects of porosity on mechanical properties and deformation behavior of four isotropic polycrystalline graphites were studied. The pore size distributions of the graphites were measured using a conventional mercury penetration technique. The average pore radius of ISO-88 graphite was about one-tenth of that of ISEM-1, IG-11 or IG-15 graphites. Young's modulus of the graphites decreased with increasing porosity. The stress-strain curve of each graphite was measured in its lateral and axial directions. Young's modulus of graphite decreased with increasing load. The plastic strain at a given compressive load was calculated from the stress-strain curve and the initial gradient of the unloading curve at the load. The ratio of lateral plastic strain to axial plastic strain for the graphites was less than 0.5, indicating that the volume of the graphites decreased during compressive loading. By assuming that the volume change was caused by contraction of pores, plastic strain associated with contraction of pores was calculated from the axial plastic strain and lateral plastic strain by slips along the basal planes. The plastic strain increased with increasing axial plastic strain and porosity of graphite. (author)

  12. Mesoscopic Features of Plastic Strain in Step Yield

    Science.gov (United States)

    Krishtal, M. M.

    2002-09-01

    A specially developed method for isolating the macroscopically homogeneous part of plastic strain in step yield (SY) of materials is used for analyzing stress-strain curves of alloy AMg5 obtained at various strain rates in the range of appearance of SY. It is shown that the beginning of the SY corresponds to the inflection point in the linear dependence of the true stresses ( S) on the true plastic strain ( e) in S - e 1/2 coordinates, which is identified as the appearance of a new individual strain stage caused by the change in the strain mechanism at the mesolevel. The established change in the strain mechanism is shown to consist in an abrupt growth of the elementary volume of plastic strain due to the appearance of a space-time correlation in the development of the strain microprocesses, which is responsible for macrolocalization and general loss of the stability of the strain. The developed experimental and computational method is used to determine the rate sensitivity of the strain resistance to step yield, which is a positive quantity that increases with the strain.

  13. Strain Rate Effect on Tensile Behavior for a High Specific Strength Steel: From Quasi-Static to Intermediate Strain Rates

    OpenAIRE

    Wei Wang; Yan Ma; Muxin Yang; Ping Jiang; Fuping Yuan; Xiaolei Wu

    2017-01-01

    The strain rate effect on the tensile behaviors of a high specific strength steel (HSSS) with dual-phase microstructure has been investigated. The yield strength, the ultimate strength and the tensile toughness were all observed to increase with increasing strain rates at the range of 0.0006 to 56/s, rendering this HSSS as an excellent candidate for an energy absorber in the automobile industry, since vehicle crushing often happens at intermediate strain rates. Back stress hardening has been ...

  14. Revealing differences in metabolic flux distributions between a mutant strain and its parent strain Gluconacetobacter xylinus CGMCC 2955.

    Directory of Open Access Journals (Sweden)

    Cheng Zhong

    Full Text Available A better understanding of metabolic fluxes is important for manipulating microbial metabolism toward desired end products, or away from undesirable by-products. A mutant strain, Gluconacetobacter xylinus AX2-16, was obtained by combined chemical mutation of the parent strain (G. xylinus CGMCC 2955 using DEC (diethyl sulfate and LiCl. The highest bacterial cellulose production for this mutant was obtained at about 11.75 g/L, which was an increase of 62% compared with that by the parent strain. In contrast, gluconic acid (the main byproduct concentration was only 5.71 g/L for mutant strain, which was 55.7% lower than that of parent strain. Metabolic flux analysis indicated that 40.1% of the carbon source was transformed to bacterial cellulose in mutant strain, compared with 24.2% for parent strain. Only 32.7% and 4.0% of the carbon source were converted into gluconic acid and acetic acid in mutant strain, compared with 58.5% and 9.5% of that in parent strain. In addition, a higher flux of tricarboxylic acid (TCA cycle was obtained in mutant strain (57.0% compared with parent strain (17.0%. It was also indicated from the flux analysis that more ATP was produced in mutant strain from pentose phosphate pathway (PPP and TCA cycle. The enzymatic activity of succinate dehydrogenase (SDH, which is one of the key enzymes in TCA cycle, was 1.65-fold higher in mutant strain than that in parent strain at the end of culture. It was further validated by the measurement of ATPase that 3.53-6.41 fold higher enzymatic activity was obtained from mutant strain compared with parent strain.

  15. A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

    Directory of Open Access Journals (Sweden)

    Waris Obitayo

    2012-01-01

    Full Text Available The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

  16. Strain-controlled electrocatalysis on multimetallic nanomaterials

    Science.gov (United States)

    Luo, Mingchuan; Guo, Shaojun

    2017-11-01

    Electrocatalysis is crucial for the development of clean and renewable energy technologies, which may reduce our reliance on fossil fuels. Multimetallic nanomaterials serve as state-of-the-art electrocatalysts as a consequence of their unique physico-chemical properties. One method of enhancing the electrocatalytic performance of multimetallic nanomaterials is to tune or control the surface strain of the nanomaterials, and tremendous progress has been made in this area in the past decade. In this Review, we summarize advances in the introduction, tuning and quantification of strain in multimetallic nanocrystals to achieve more efficient energy conversion by electrocatalysis. First, we introduce the concept of strain and its correlation with other key physico-chemical properties. Then, using the electrocatalytic reduction of oxygen as a model reaction, we discuss the underlying mechanisms behind the strain-adsorption-reactivity relationship based on combined classical theories and models. We describe how this knowledge can be harnessed to design multimetallic nanocrystals with optimized strain to increase the efficiency of oxygen reduction. In particular, we highlight the unexpectedly beneficial (and previously overlooked) role of tensile strain from multimetallic nanocrystals in improving electrocatalysis. We conclude by outlining the challenges and offering our perspectives on the research directions in this burgeoning field.

  17. Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis

    Science.gov (United States)

    Khan, Meraj A.; Philip, Lijy M.; Cheung, Guillaume; Vadakepeedika, Shawn; Grasemann, Hartmut; Sweezey, Neil; Palaniyar, Nades

    2018-01-01

    Neutrophils migrating from the blood (pH 7.35–7.45) into the surrounding tissues encounter changes in extracellular pH (pHe) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H+ ions reducing the intracellular pH (pHi). Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET) formation (NETosis) is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS) and neutrophil protease activity, stimulating NETosis. Here, we found that raising pHe (ranging from 6.6 to 7.8; every 0.2 units) increased pHi of both activated and resting neutrophils within 10–20 min (Seminaphtharhodafluor dual fluorescence measurements). Since Nox activity generates H+ ions, pHi is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging) during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs). In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots) and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative)-, and Staphylococcus aureus (Gram-positive)-induced NETosis. Thus, higher pHe promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pHe-mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM) increases NETosis. Each Tris molecule can bind 3H+ ions, whereas each bicarbonate HCO3− ion binds 1H+ ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar

  18. Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis

    Directory of Open Access Journals (Sweden)

    Meraj A. Khan

    2018-02-01

    Full Text Available Neutrophils migrating from the blood (pH 7.35–7.45 into the surrounding tissues encounter changes in extracellular pH (pHe conditions. Upon activation of NADPH oxidase 2 (Nox, neutrophils generate large amounts of H+ ions reducing the intracellular pH (pHi. Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET formation (NETosis is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS and neutrophil protease activity, stimulating NETosis. Here, we found that raising pHe (ranging from 6.6 to 7.8; every 0.2 units increased pHi of both activated and resting neutrophils within 10–20 min (Seminaphtharhodafluor dual fluorescence measurements. Since Nox activity generates H+ ions, pHi is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs. In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative-, and Staphylococcus aureus (Gram-positive-induced NETosis. Thus, higher pHe promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pHe-mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM increases NETosis. Each Tris molecule can bind 3H+ ions, whereas each bicarbonate HCO3− ion binds 1H+ ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar

  19. Ratchetting strain prediction

    International Nuclear Information System (INIS)

    Noban, Mohammad; Jahed, Hamid

    2007-01-01

    A time-efficient method for predicting ratchetting strain is proposed. The ratchetting strain at any cycle is determined by finding the ratchetting rate at only a few cycles. This determination is done by first defining the trajectory of the origin of stress in the deviatoric stress space and then incorporating this moving origin into a cyclic plasticity model. It is shown that at the beginning of the loading, the starting point of this trajectory coincides with the initial stress origin and approaches the mean stress, displaying a power-law relationship with the number of loading cycles. The method of obtaining this trajectory from a standard uniaxial asymmetric cyclic loading is presented. Ratchetting rates are calculated with the help of this trajectory and through the use of a constitutive cyclic plasticity model which incorporates deviatoric stresses and back stresses that are measured with respect to this moving frame. The proposed model is used to predict the ratchetting strain of two types of steels under single- and multi-step loadings. Results obtained agree well with the available experimental measurements

  20. Strain measurement based battery testing

    Science.gov (United States)

    Xu, Jeff Qiang; Steiber, Joe; Wall, Craig M.; Smith, Robert; Ng, Cheuk

    2017-05-23

    A method and system for strain-based estimation of the state of health of a battery, from an initial state to an aged state, is provided. A strain gauge is applied to the battery. A first strain measurement is performed on the battery, using the strain gauge, at a selected charge capacity of the battery and at the initial state of the battery. A second strain measurement is performed on the battery, using the strain gauge, at the selected charge capacity of the battery and at the aged state of the battery. The capacity degradation of the battery is estimated as the difference between the first and second strain measurements divided by the first strain measurement.

  1. Strain characterization of FinFETs using Raman spectroscopy

    International Nuclear Information System (INIS)

    Kaleli, B.; Hemert, T. van; Hueting, R.J.E.; Wolters, R.A.M.

    2013-01-01

    Metal induced strain in the channel region of silicon (Si) fin-field effect transistor (FinFET) devices has been characterized using Raman spectroscopy. The strain originates from the difference in thermal expansion coefficient of Si and titanium-nitride. The Raman map of the device region is used to determine strain in the channel after preparing the device with the focused ion beam milling. Using the Raman peak shift relative to that of relaxed Si, compressive strain values up to – 0.88% have been obtained for a 5 nm wide silicon fin. The strain is found to increase with reducing fin width though it scales less than previously reported results from holographic interferometry. In addition, finite-element method (FEM) simulations have been utilized to analyze the amount of strain generated after thermal processing. It is shown that obtained FEM simulated strain values are in good agreement with the calculated strain values obtained from Raman spectroscopy. - Highlights: ► Strain is characterized in nanoscale devices with Raman spectroscopy. ► There is a fin width dependence of the originated strain. ► Strain levels obtained from this technique is in correlation with device simulations

  2. Streptococcus mitis Strains Causing Severe Clinical Disease in Cancer Patients

    Science.gov (United States)

    Sahasrabhojane, Pranoti; Saldana, Miguel; Yao, Hui; Su, Xiaoping; Horstmann, Nicola; Thompson, Erika; Flores, Anthony R.

    2014-01-01

    The genetically diverse viridans group streptococci (VGS) are increasingly recognized as the cause of a variety of human diseases. We used a recently developed multilocus sequence analysis scheme to define the species of 118 unique VGS strains causing bacteremia in patients with cancer; Streptococcus mitis (68 patients) and S. oralis (22 patients) were the most frequently identified strains. Compared with patients infected with non–S. mitis strains, patients infected with S. mitis strains were more likely to have moderate or severe clinical disease (e.g., VGS shock syndrome). Combined with the sequence data, whole-genome analyses showed that S. mitis strains may more precisely be considered as >2 species. Furthermore, we found that multiple S. mitis strains induced disease in neutropenic mice in a dose-dependent fashion. Our data define the prominent clinical effect of the group of organisms currently classified as S. mitis and lay the groundwork for increased understanding of this understudied pathogen. PMID:24750901

  3. Studies on Drosophila radiosensitive strains

    International Nuclear Information System (INIS)

    Varentsova, E.P.; Zakharov, I.A.

    1976-01-01

    45 of radiosensitive strains of Drosophila melanogaster were isolated by Curly/Lobe technique after EMS treatment of Livadia population males. The lethality of non-Curly late larvae after gamma-irradiation (4000r) characterized radiosensitivity strains. Most of them exhibited higher frequency of the spontaneous dominant lethals (up to 69%). The males of 6 strains were semi-sterile. 5 of these strains exhibited higher frequency of X-chromosome non-disjunction

  4. Haemophilus influenzae Strains in Tunisian Children

    Directory of Open Access Journals (Sweden)

    Mzilem Sabrine

    2017-11-01

    Full Text Available Background: Haemophilus influenzae, a major pathogen causing respiratory tract infections and meningitis, is becoming increasingly resistant to narrow spectrum penicillin. Investigating the reasons for this resistance is challenging. Methods: The sequences of the ftsI gene, encoding the transpeptidase domain of penicillin binding protein (PBP3, were determined for 44 strains of Haemophilus influenzae with reduced susceptibility to β-lactam antibiotics. Strains, isolated from children, were analyzed for genetic relationship by pulsed-field gel electrophoresis (PFGE. Results: Sequence analysis of the ftsI gene revealed different mutations. We used this polymorphism to classify the different strains into three groups: (I (n=3, II (n=36, including H. influenzae ATCC 49247, this group was divided into four subgroups and III (n=5. In each group various substitutions were observed. Conclusion: The increasing number of Haemophilus influenzae strains with reduced susceptibility to β-lactam due to mutations in the ftsI gene, is becoming a serious health issue in Tunisia. The resistance to β-lactam was observed in both strains that produce β-lactamase and those that do not. The level of resistance is remarkably high in our country.

  5. Variation in the strain anisotropy of Zircaloy with temperature and strain

    International Nuclear Information System (INIS)

    Hindle, E.D.; Worswick, D.

    1984-01-01

    The strong crystallographic texture which is developed during the fabrication of zirconium-based alloys causes pronounced anisotropy in their mechanical properties, particularly deformation. The tendency for circular-section tension specimens with a high concentration of basal poles in one direction to become elliptical when deformed in tension has been used in this study to provide quantitative data on the effects of both strain and temperature on strain anisotropy. Tension tests were carried out over a temperature range of 293 to 1193 K on specimens machined from Zircaloy-2 plate. The strain anisotropy was found to increase markedly at temperatures over 923 K, reaching a maximum in the region of 1070 K. The strain anisotropy increased with increasing strain in this temperature region. The study was extended to Zircaloy-4 pressurized-water reactor fuel cladding by carrying out tube swelling tests and evaluating the axial deformation produced. Although scatter in the test results was higher than that exhibited in the tension tests, the general trend in the data was similar. The effects of the strain anisotropy observed are discussed in relation to the effects of temperature on the ductility of Zircaloy fuel cladding tubes during postulated largebreak loss-of-coolant accidents

  6. Effects of gauge volume on pseudo-strain induced in strain measurement using time-of-flight neutron diffraction

    Science.gov (United States)

    Suzuki, Hiroshi; Harjo, Stefanus; Abe, Jun; Xu, Pingguang; Aizawa, Kazuya; Akita, Koichi

    2013-07-01

    Spurious or pseudo-strains observed in time-of-flight (TOF) neutron diffraction due to neutron attenuation, surface-effects and a strain distribution within the gauge volume were investigated. Experiments were carried out on annealed and bent ferritic steel bars to test these effects. The most representative position in the gauge volume corresponds to the neutron-weighted center of gravity (ncog), which takes into account variations in intensity within the gauge volume due to neutron attenuation and/or absence of material in the gauge volume. The average strain in the gauge volume was observed to be weighted towards the ncog position but following an increase in the size of the gauge volume the weighted average strain was changed because of the change in the ncog position when a strain gradient appeared within the gauge volume. On the other hand, typical pseudo-strains, which are well known, did appear in through-surface strain measurements when the gauge volume was incompletely filled by the sample. Tensile pseudo-strains due to the surface-effect increased near the sample surface and exhibited a similar trend regardless of the size of the gauge volume, while the pseudo-strains increased faster for the smaller gauge volume. Furthermore, a pseudo-strain due to a change in the ncog position was observed even when the gauge volume was perfectly filled in the sample, and it increased with an increase in the size of the gauge volume. These pseudo-strains measured were much larger than those simulated by the conventional modeling, whereas they were simulated by taking into account an incident neutron beam divergence additionally in the model. Therefore, the incident divergence of the incident neutron beam must be carefully designed to avoid pseudo-strains in time-of-flight neutron diffractometry.

  7. Strain-tuning of edge magnetism in zigzag graphene nanoribbons.

    Science.gov (United States)

    Yang, Guang; Li, Baoyue; Zhang, Wei; Ye, Miao; Ma, Tianxing

    2017-09-13

    Using the determinant quantum Monte-Carlo method, we elucidate the strain tuning of edge magnetism in zigzag graphene nanoribbons. Our intensive numerical results show that a relatively weak Coulomb interaction may induce a ferromagnetic-like behaviour with a proper strain, and the edge magnetism can be enhanced greatly as the strain along the zigzag edge increases, which provides another way to control graphene magnetism even at room temperature.

  8. Computational modeling of dynamic mechanical properties of pure polycrystalline magnesium under high loading strain rates

    Directory of Open Access Journals (Sweden)

    Li Qizhen

    2015-01-01

    Full Text Available Computational simulations were performed to investigate the dynamic mechanical behavior of pure polycrystalline magnesium under different high loading strain rates with the values of 800, 1000, 2000, and 3600 s−1. The Johnson-Cook model was utilized in the simulations based on finite element modeling. The results showed that the simulations provided well-matched predictions of the material behavior such as the strain rate-time history, the stress-strain curve, and the temperature increase. Under high loading strain rates, the tested material experienced linear strain hardening at the early stage of plastic deformation, increased strain hardening at the intermediate plastic deformation region, and decreased strain hardening at the region before fracture. The strain hardening rates for the studied high loading strain rate cases do not vary much with the change of strain rates.

  9. [Echinococcus and strain concepts].

    Science.gov (United States)

    Utük, Armağan Erdem; Simsek, Sami

    2008-01-01

    Hydatid disease (echinococcosis) is one of the most important parasitic zoonoses and remains a public health and economic problem all over the world. Echinococcus granulosus includes a number of genetic variants and, up to date, analyses of mitochondrial DNA sequences have identified ten distinct genetic types (genotypes G1-10). This categorization follows closely the pattern of strain variation emerging based on biological characteristics. The extensive variation in E. granulosus may influence life-cycle patterns, host specificity, development rate, antigenicity, transmission dynamics, sensitivity to chemotherapeutic agents, and pathology. In this review, the recent genetic characterizations of Echinococcus genus have been summarized.

  10. Reconstruction of axisymmetric strain distributions via neutron strain tomography

    Science.gov (United States)

    Abbey, Brian; Zhang, Shu Yan; Vorster, Wim; Korsunsky, Alexander M.

    2012-01-01

    Predicting the behaviour of structural components under a particular set of loading conditions requires knowledge of the residual elastic strain distribution throughout the bulk of these components. Characterising the 3D strain state at any particular point involves the measurement of six independent components which make up the second order strain tensor. Mapping the complete strain distribution throughout large volumes thus presents significant practical challenges. One possible solution to this problem is to reconstruct the 3D variation of strain components using tomographic techniques. The basic principle underpinning this idea is that the multi-component strain tensor can be reconstructed from a redundant set of lower order projection data. Here we demonstrate this fundamental concept for two samples: a shrink fit 'ring-and-plug' sample, and a spray-quenched circular cylinder, both possessing axially symmetric internal strain distribution. We present and contrast different approaches to the strain tomography problem. The methods described here can also be readily applied to high-energy X-ray diffraction measurements and represent an important step toward developing the tomographic reconstruction framework for strain tensor distributions of arbitrary complexity. The major benefit of neutron strain tomography is that the incident beam flux is utilised more fully, greatly reducing the data collection times. Using micro-channel plate (MCP) neutron detectors, a spatial resolution of the order of 0.1 mm can be achieved [1].

  11. Splicing landscape of the eight collaborative cross founder strains.

    Science.gov (United States)

    Zheng, Christina L; Wilmot, Beth; Walter, Nicole Ar; Oberbeck, Denesa; Kawane, Sunita; Searles, Robert P; McWeeney, Shannon K; Hitzemann, Robert

    2015-02-05

    The Collaborative Cross (CC) is a large panel of genetically diverse recombinant inbred mouse strains specifically designed to provide a systems genetics resource for the study of complex traits. In part, the utility of the CC stems from the extensive genome-wide annotations of founder strain sequence and structural variation. Still missing, however, are transcriptome-specific annotations of the CC founder strains that could further enhance the utility of this resource. We provide a comprehensive survey of the splicing landscape of the 8 CC founder strains by leveraging the high level of alternative splicing within the brain. Using deep transcriptome sequencing, we found that a majority of the splicing landscape is conserved among the 8 strains, with ~65% of junctions being shared by at least 2 strains. We, however, found a large number of potential strain-specific splicing events as well, with an average of ~3000 and ~500 with ≥3 and ≥10 sequence read coverage, respectively, within each strain. To better understand strain-specific splicing within the CC founder strains, we defined criteria for and identified high-confidence strain-specific splicing events. These splicing events were defined as exon-exon junctions 1) found within only one strain, 2) with a read coverage ≥10, and 3) defined by a canonical splice site. With these criteria, a total of 1509 high-confidence strain-specific splicing events were identified, with the majority found within two of the wild-derived strains, CAST and PWK. Strikingly, the overwhelming majority, 94%, of these strain-specific splicing events are not yet annotated. Strain-specific splicing was also located within genomic regions recently reported to be over- and under-represented within CC populations. Phenotypic characterization of CC populations is increasing; thus these results will not only aid in further elucidating the transcriptomic architecture of the individual CC founder strains, but they will also help in guiding

  12. Efficient characterization of inhomogeneity in contraction strain pattern.

    Science.gov (United States)

    Nazzal, Christina M; Mulligan, Lawrence J; Criscione, John C

    2012-05-01

    Cardiac dyssynchrony often accompanies patients with heart failure (HF) and can lead to an increase in mortality rate. Cardiac resynchronization therapy (CRT) has been shown to provide substantial benefits to the HF population with ventricular dyssynchrony; however, there still exists a group of patients who do not respond to this treatment. In order to better understand patient response to CRT, it is necessary to quantitatively characterize both electrical and mechanical dyssynchrony. The quantification of mechanical dyssynchrony via characterization of contraction strain field inhomogeneity is the focus of this modeling investigation. Raw data from a 3D finite element (FE) model were received from Roy Kerckhoffs et al. and analyzed in MATLAB. The FE model consisted of canine left and right ventricles coupled to a closed circulation with the effects of the pericardium acting as a pressure on the epicardial surface. For each of three simulations (normal synchronous, SYNC, right ventricular apical pacing, RVA, and left ventricular free wall pacing, LVFW) the Gauss point locations and values were used to generate lookup tables (LUTs) with each entry representing a location in the heart. In essence, we employed piecewise cubic interpolation to generate a fine point cloud (LUTs) from a course point cloud (Gauss points). Strain was calculated in the fiber direction and was then displayed in multiple ways to better characterize strain inhomogeneity. By plotting average strain and standard deviation over time, the point of maximum contraction and the point of maximal inhomogeneity were found for each simulation. Strain values were organized into seven strain bins to show operative strain ranges and extent of inhomogeneity throughout the heart wall. In order to visualize strain propagation, magnitude, and inhomogeneity over time, we created 2D area maps displaying strain over the entire cardiac cycle. To visualize spatial strain distribution at the time point of maximum

  13. Sadovskii vortex in strain

    Science.gov (United States)

    Freilich, Daniel; Llewellyn Smith, Stefan

    2014-11-01

    A Sadovskii vortex is a patch of fluid with uniform vorticity surrounded by a vortex sheet. Using a boundary element type method, we investigate the steady states of this flow in an incompressible, inviscid straining flow. Outside the vortex, the fluid is irrotational. In the limiting case where the entire circulation is due to the vortex patch, this is a patch vortex (Moore & Saffman, Aircraft wake turbulence and its detection 1971). In the other limiting case, where all the circulation is due to the vortex sheet, this is a hollow vortex (Llewellyn Smith and Crowdy, J. Fluid Mech. 691, 2012). This flow has two governing nondimensional parameters, relating the strengths of the straining field, vortex sheet, and patch vorticity. We study the relationship between these two parameters, and examine the shape of the resulting vortices. We also work towards a bifurcation diagram of the steady states of the Sadovskii vortex in an attempt to understand the connection between vortex sheet and vortex patch desingularizations of the point vortex. Support from NSF-CMMI-0970113.

  14. Comparison of historic and contemporary strains of Senecavirus A

    Science.gov (United States)

    Objective One hypothesis for the sudden increase in SVA cases in the United States was that contemporary strains were more pathogenic than historical strains. Our objective was to study disease progression of historical and contemporary SVA isolates in growing pigs. Materials and Methods Commercial ...

  15. Colony Dimorphism in Bradyrhizobium Strains

    Science.gov (United States)

    Sylvester-Bradley, Rosemary; Thornton, Philip; Jones, Peter

    1988-01-01

    Ten isolates of Bradyrhizobium spp. which form two colony types were studied; the isolates originated from a range of legume species. The two colony types differed in the amount of gum formed or size or both, depending on the strain. Whole 7-day-old colonies of each type were subcultured to determine the proportion of cells which had changed to the other type. An iterative computerized procedure was used to determine the rate of switching per generation between the two types and to predict proportions reached at equilibrium for each strain. The predicted proportions of the wetter (more gummy) or larger colony type at equilibrium differed significantly between strains, ranging from 0.9999 (strain CIAT 2383) to 0.0216 (strain CIAT 2469), because some strains switched faster from dry to wet (or small to large) and others switched faster from wet to dry (or large to small). Predicted equilibrium was reached after about 140 generations in strain USDA 76. In all but one strain (CIAT 3030) the growth rate of the wetter colony type was greater than or similar to that of the drier type. The mean difference in generation time between the two colony types was 0.37 h. Doubling times calculated for either colony type after 7 days of growth on the agar surface ranged from 6.0 to 7.3 h. The formation of two persistent colony types by one strain (clonal or colony dimorphism) may be a common phenomenon among Bradyrhizobium strains. Images PMID:16347599

  16. Price increase

    CERN Multimedia

    2006-01-01

    Please take note that after five years of stable prices at Restaurant No 1 a price increase will come into force on 1st January 2006. This increase has been agreed after discussions between the CSR (Comité de Surveillance des Restaurants) and the catering company Novae and will reflect the inflation rate of the last few years. In addition, a new children's menu will be introduced, as well as 'Max Havelaar' fair-trade coffee at a price of 1.70 CHF.

  17. Price increase

    CERN Multimedia

    2005-01-01

    Please take note that after five years of stable prices at Restaurant No 1 a price increase will come into force on 1st January 2006. This increase has been agreed after discussions between the CSR (Comité de Surveillance des Restaurants) and the catering company Novae and will reflect the inflation rate of the last few years. In addition, a new children's menu will be introduced as well as 'Max Havelaar' fair-trade coffee at a price of 1.70 CHF.

  18. Health-promoting properties exhibited by Lactobacillus helveticus strains.

    Science.gov (United States)

    Skrzypczak, Katarzyna; Gustaw, Waldemar; Waśko, Adam

    2015-01-01

    Many strains belonging to lactobacilli exert a variety of beneficial health effects in humans and some of the bacteria are regarded as probiotic microorganisms. Adherence and capabilities of colonization by Lactobacillus strains of the intestinal tract is a prerequisite for probiotic strains to exhibit desired functional properties. The analysis conducted here aimed at screening strains of Lactobacillus helveticus possessing a health-promoting potential. The molecular analysis performed, revealed the presence of a slpA gene encoding the surface S-layer protein SlpA (contributing to the immunostimulatory activity of L. helveticus M 92 probiotic strain) in all B734, DSM, T80, and T105 strains. The product of gene amplification was also identified in a Bifidobacterium animalis ssp. lactis BB12 probiotic strain. SDS-PAGE of a surface protein extract demonstrated the presence of a protein with a mass of about 50 kDa in all strains, which refers to the mass of the S-layer proteins. These results are confirmed by observations carried with transmission electron microscopy, where a clearly visible S-layer was registered in all the strains analyzed. The in vitro study results obtained indicate that the strongest adhesion capacity to epithelial cells (HT-29) was demonstrated by L. helveticus B734, while coaggregation with pathogens was highly diverse among the tested strains. The percentage degree of coaggregation was increasing with the incubation time. After 5 h of incubation, the strongest ability to coaggregate with Escherichia coli was expressed by T104. The T80 strain demonstrated a significant ability to co-aggregate with Staphylococcus aureus, while DSM with Bacillus subtilis. For B734, the highest values of co-aggregation coefficient was noted in samples with Salmonella. The capability of autoaggregation, antibiotic susceptibility, resistance to increasing salt concentrations, and strain survival in simulated small intestinal juice were also analyzed.

  19. Strain rate effect on the mechanical behavior of the anterior cruciate ligament-bone complex

    OpenAIRE

    Pioletti, Dominique P.; Rakotomanana, L. R.; Leyvraz, P. F.

    1999-01-01

    Traction tests were performed on the bovine anterior cruciate ligament-bone complex at seven strain rates (0.1, 1, 5, 10, 20, 30, 40%/s). Corresponding stress-strain curves showed that, for a given strain level, the stress increased with the augmentation of the strain rate. This phenomenon was important since the stress increased by a factor of three between the tests performed at the lowest and highest strain rates. The influence of the strain rate was quantified with a new variable called t...

  20. Strain Rate Effect on Tensile Behavior for a High Specific Strength Steel: From Quasi-Static to Intermediate Strain Rates

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2017-12-01

    Full Text Available The strain rate effect on the tensile behaviors of a high specific strength steel (HSSS with dual-phase microstructure has been investigated. The yield strength, the ultimate strength and the tensile toughness were all observed to increase with increasing strain rates at the range of 0.0006 to 56/s, rendering this HSSS as an excellent candidate for an energy absorber in the automobile industry, since vehicle crushing often happens at intermediate strain rates. Back stress hardening has been found to play an important role for this HSSS due to load transfer and strain partitioning between two phases, and a higher strain rate could cause even higher strain partitioning in the softer austenite grains, delaying the deformation instability. Deformation twins are observed in the austenite grains at all strain rates to facilitate the uniform tensile deformation. The B2 phase (FeAl intermetallic compound is less deformable at higher strain rates, resulting in easier brittle fracture in B2 particles, smaller dimple size and a higher density of phase interfaces in final fracture surfaces. Thus, more energy need be consumed during the final fracture for the experiments conducted at higher strain rates, resulting in better tensile toughness.

  1. Isolation of rifampicin resistant Flavobacterium psychrophilum strains and their potential as live attenuated vaccine candidates

    Science.gov (United States)

    Previous studies have demonstrated that passage of pathogenic bacteria on increasing concentrations of the antibiotic rifampicin leads to the attenuation of virulence and these resistant strains may serve as live attenuated vaccines. Two rifampicin resistant strains of Flavobacterium psychrophilum,...

  2. Types of strain among family members of individuals with autism spectrum disorder across the lifespan.

    Science.gov (United States)

    Shivers, Carolyn M; Krizova, Katarina; Lee, Gloria K

    2017-09-01

    Although increased caregiver strain is often found among family caregivers of individuals with autism spectrum disorder, it is still unclear as to how different types of strain relate to amount and types of caregiving across the lifespan. The present study examined different types of strain (i.e. subjective internalized strain, subjective externalized strain, and objective strain) and how such strain relates to the amount of caregiving responsibilities. Data was collected via online survey from a sample of 193 family caregivers of individuals with ASD from the United States, Canada, and the Republic of Ireland. Participants completed measures of strain and caregiving responsibilities, as well as coping, demographics, and services needed and received by the individual with ASD. Caregivers reported higher levels of objective strain than subjective, and caregiving responsibility was related to objective and subjective internalized strain. Coping style was strongly correlated with all types of strain, and unmet service needs were significantly related to objective and subjective internalized strain. Caregiving behaviors were only related to objective strain. The present results indicate that, although caregiving responsibility is related to objective and subjective internalized strain, the relationship is perhaps not as strong as the relationship between coping mechanisms and strain. Future research is needed to understand different types of strain and develop strategies to help caregivers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Angiogenesis is induced by airway smooth muscle strain.

    Science.gov (United States)

    Hasaneen, Nadia A; Zucker, Stanley; Lin, Richard Z; Vaday, Gayle G; Panettieri, Reynold A; Foda, Hussein D

    2007-10-01

    Angiogenesis is an important feature of airway remodeling in both chronic asthma and chronic obstructive pulmonary disease (COPD). Airways in those conditions are exposed to excessive mechanical strain during periods of acute exacerbations. We recently reported that mechanical strain of human airway smooth muscle (HASM) led to an increase in their proliferation and migration. Sustained growth in airway smooth muscle in vivo requires an increase in the nutritional supply to these muscles, hence angiogenesis. In this study, we examined the hypothesis that cyclic mechanical strain of HASM produces factors promoting angiogenic events in the surrounding vascular endothelial cells. Our results show: 1) a significant increase in human lung microvascular endothelial cell (HMVEC-L) proliferation, migration, and tube formation following incubation in conditioned media (CM) from HASM cells exposed to mechanical strain; 2) mechanical strain of HASM cells induced VEGF expression and release; 3) VEGF neutralizing antibodies inhibited the proliferation, migration, and tube formations of HMVEC-L induced by the strained airway smooth muscle CM; 4) mechanical strain of HASM induced a significant increase in hypoxia-inducible factor-1alpha (HIF-1alpha) mRNA and protein, a transcription factor required for VEGF gene transcription; and 5) mechanical strain of HASM induced HIF-1alpha/VEGF through dual phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) and ERK pathways. In conclusion, exposing HASM cells to mechanical strain induces signal transduction pathway through PI3K/Akt/mTOR and ERK pathways that lead to an increase in HIF-1alpha, a transcription factor required for VEGF expression. VEGF release by mechanical strain of HASM may contribute to the angiogenesis seen with repeated exacerbation of asthma and COPD.

  4. Asymptomatic bacteriuria Escherichia coli strains

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast...... to uropathogenic E. coli (UPEC) that cause symptomatic UTI, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the growth characteristics in human urine as well as adhesin repertoire of nine ABU strains; the ability of ABU strains to compete...

  5. Hydrogen production from microbial strains

    Science.gov (United States)

    Harwood, Caroline S; Rey, Federico E

    2012-09-18

    The present invention is directed to a method of screening microbe strains capable of generating hydrogen. This method involves inoculating one or more microbes in a sample containing cell culture medium to form an inoculated culture medium. The inoculated culture medium is then incubated under hydrogen producing conditions. Once incubating causes the inoculated culture medium to produce hydrogen, microbes in the culture medium are identified as candidate microbe strains capable of generating hydrogen. Methods of producing hydrogen using one or more of the microbial strains identified as well as the hydrogen producing strains themselves are also disclosed.

  6. Internal residual strain mapping in carburized chrome molybdenum steel after quenching by neutron strain scanning

    International Nuclear Information System (INIS)

    Sakaida, Yoshihisa; Serizawa, Takanobu; Manzanka, Michiya

    2011-01-01

    A hollow circular cylinder specimen with an annular U-notch of chrome molybdenum steel with 0.20 mass% C (SCM420) was carburized in carrier gas and quenched in oil bath. In order to determine the case depth, the specimen was cut off and carbon content and Vickers hardness gradients were measured experimentally near the carburized surface. The residual strain mapping in the interior of carburized cylinder was conducted nondestructively by neutron strain scanning. In this study, the neutron diffraction from Fe-211 plane was used for strain scanning. The neutron wavelength was tuned to 0.1654nm so that diffraction angle became about 90deg. Radial, hoop and axial residual strains were measured by scanning diffracting volume along the axial direction of cylinder specimen. Each residual strain was calculated from lattice spacing change. Unstressed lattice spacing was determined experimentally using reference coupon specimens that were cut from the interior of same carburized cylinder. As a result, the diffraction peak width at half height, FWHM, near the carburized surface was about 3.7 times wider than that of coupon specimens. On the other hand, the most peak widths in the interior equaled to that of coupon specimens. Peak width broadened slightly as the diffracting volume approached the carburized case layer. From the center to the quarter of cylinder specimen, the hoop and axial strains were tensile, and the radial one was compressive in the interior. From the quarter to the edge of the cylinder specimen, the hoop tensile strain increased, radial and axial strains changed to tensile and compressive, respectively. Therefore, the interior of the cylinder specimen was found to be deformed elastically to balance the existence of compressive residual stresses in the carburized case layer. (author)

  7. Dynamic strain measurements in a sliding microstructured contact

    International Nuclear Information System (INIS)

    Bennewitz, Roland; David, Jonathan; Lannoy, Charles-Francois de; Drevniok, Benedict; Hubbard-Davis, Paris; Miura, Takashi; Trichtchenko, Olga

    2008-01-01

    A novel experiment is described which measures the tangential strain development across the contact between a PDMS (polydimethylsiloxane) block and a glass surface during the initial stages of sliding. The surface of the PDMS block has been microfabricated to take the form of a regular array of pyramidal tips at 20 μm separation. Tangential strain is measured by means of light scattering from the interface between the block and surface. Three phases are observed in all experiments: initial shear deformation of the whole PDMS block, a pre-sliding tangential compression of the tip array with stepwise increase of the compressive strain, and sliding in stick-slip movements as revealed by periodic variation of the strain. The stick-slip sliding between the regular tip array and the randomly rough counter surface always takes on the periodicity of the tip array. The fast slip can cause either a sudden increase or a sudden decrease in compressive strain

  8. TL transgenic mouse strains

    International Nuclear Information System (INIS)

    Obata, Y.; Matsudaira, Y.; Hasegawa, H.; Tamaki, H.; Takahashi, T.; Morita, A.; Kasai, K.

    1993-01-01

    As a result of abnormal development of the thymus of these mice, TCR αβ lineage of the T cell differentiation is disturbed and cells belonging to the TCR γδ CD4 - CD8 - double negative (DN) lineage become preponderant. The γδ DN cells migrate into peripheral lymphoid organs and constitute nearly 50% of peripheral T cells. Immune function of the transgenic mice is severely impaired, indicating that the γδ cells are incapable of participating in these reactions. Molecular and serological analyses of T-cell lymphomas reveal that they belong to the γδ lineage. Tg.Tla a -3-1 mice should be useful in defining the role of TL in normal and abnormal T cell differentiation as well as in the development of T-cell lymphomas, and further they should facilitate studies on the differentiation and function of γδ T cells. We isolated T3 b -TL gene from B6 mice and constructed a chimeric gene in which T3 b -TL is driven by the promoter of H-2K b . With the chimeric gene, two transgenic mouse strains, Tg. Con.3-1 and -2 have been derived in C3H background. Both strains express TL antigen in various tissues including skin. The skin graft of transgenic mice on C3H and (B6 X C3H)F 1 mice were rejected. In the mice which rejected the grafts, CD8 + TCRαβ cytotoxic T cells (CTL) against TL antigens were recognized. The recognition of TL by CTL did not require the antigen presentation by H-2 molecules. The results indicated that TL antigen in the skin becomes a transplantation antigen and behaves like a typical allogeneic MHC class I antigen. The facts that (B6 X C3H)F 1 mice rejected the skin expressing T3 b -TL antigen and induced CTL that killed TL + lymphomas of B6 origin revealed that TL antigen encoded by T3 b -TL is recognized as non-self in B6 mice. Experiments are now extended to analyze immune responses to TL antigen expressed on autochthonous T cell lymphomas. (J.P.N.)

  9. Strain ageing in welds of nuclear pressure vessels

    International Nuclear Information System (INIS)

    Otterberg, R.; Karlsson, C.

    1979-01-01

    Static and dynamic strain ageing have been investigated on submerged-arc welds and repair welds from plates of the pressure vessel steel A 533B. The results permit the determination of the worst strain ageing conditions existing in a nuclear pressure vessel. Static strain ageing was investigated by means of data from tension tests, hardness measurements and Charpy-V impact properties for prestrained and aged material for ageing temperatures from room temperature to 350 deg C and ageing times up to 1000h. Dynamic strain ageing was investigated by tensile tests up to 350 deg C at different strain rates. At the most static strain ageing was found to increase the impact transition temperature from -75 deg C in the as-received condition to -55 deg C after prestraining and ageing for the plate material, from -35 to -10 deg C for the submerged arc weld and from -90 to -40 deg C for the repair weld. Approximately 10 deg C of the deleterious effect is due to the effect of ageing for the two former materials whereas the corresponding figure for the repair weld amounts to 35 deg C. The dynamic strain ageing is strongest at very low strain rates at temperatures just below 300 deg C. The effect of strain ageing can be reduced by stress relief heat treatment or by other means decreasing the content of nitrogen in solution. (author)

  10. Production and Characterization of Alkaline Protease from a High Yielding and Moderately Halophilic Strain of SD11 Marine Bacteria

    Directory of Open Access Journals (Sweden)

    Hongxia Cui

    2015-01-01

    Full Text Available A marine bacterium SD11, which was isolated from sea muds (Geziwo Qinhuangdao Sea area, China, was used to produce thermostable alkaline serine nonmetal protease in the skim milk agar plate medium with 10% NaCl. The optimal temperature about the manufacture of the extracellular protease was ~60°C. The crude enzyme was stable at 20–50°C. The activity was retained to 60% and 45% after heating for 1 h at 60 and 70°C, respectively. The protease was highly active in a wide pH scope (8.0–10.0 and maximum protease activity exhibited at pH 10.0. The activity was restrained by phenylmethylsulfonyl fluoride (PMSF but mildly increased (~107% in the presence of ethylenediaminetetraacetic acid (EDTA, indicating that the production contains serine-protease(s and nonmetal protease(s. Moreover, the crude alkaline protease was active with the 5 mM Ca2+, Mn2+, Zn2+, Cu2+, Na+, and K+ that existed separately. In addition, the protease showed superduper stability when exposed to an anionic surfactant (5 mM SDS, an oxidizing agent (1% H2O2, and several organic solvents (methanol, isopropanol, and acetone. These results suggest that the marine bacterium SD11 is significant in the industry from the prospects of its ability to produce thermally stable alkaline protease.

  11. Nutritionally fastidious Ruminococct $ flovefociens : strains

    African Journals Online (AJOL)

    than those obtained in a medium containing rumen fluid. Growth of all strains was remarkably uniform. Where the same inoculum was used, differences in the qualitative com- position of the medium usually had little effect on growth. In contrast, the R. f/avefaciens strains were much more variable in their growth responses.

  12. Haldane model under nonuniform strain

    Science.gov (United States)

    Ho, Yen-Hung; Castro, Eduardo V.; Cazalilla, Miguel A.

    2017-10-01

    We study the Haldane model under strain using a tight-binding approach, and compare the obtained results with the continuum-limit approximation. As in graphene, nonuniform strain leads to a time-reversal preserving pseudomagnetic field that induces (pseudo-)Landau levels. Unlike a real magnetic field, strain lifts the degeneracy of the zeroth pseudo-Landau levels at different valleys. Moreover, for the zigzag edge under uniaxial strain, strain removes the degeneracy within the pseudo-Landau levels by inducing a tilt in their energy dispersion. The latter arises from next-to-leading order corrections to the continuum-limit Hamiltonian, which are absent for a real magnetic field. We show that, for the lowest pseudo-Landau levels in the Haldane model, the dominant contribution to the tilt is different from graphene. In addition, although strain does not strongly modify the dispersion of the edge states, their interplay with the pseudo-Landau levels is different for the armchair and zigzag ribbons. Finally, we study the effect of strain in the band structure of the Haldane model at the critical point of the topological transition, thus shedding light on the interplay between nontrivial topology and strain in quantum anomalous Hall systems.

  13. The preterm infant stomach actively degrades milk proteins with increasing breakdown across digestion time.

    Science.gov (United States)

    Demers-Mathieu, Veronique; Qu, Yunyao; Underwood, Mark A; Dallas, David C

    2018-01-31

    This study investigated the effect of time post-ingestion on gastric digestion and gastric hormones after feeding preterm infants unfortified and fortified human milk. Human milk and infant gastric samples were collected from 14 preterm (23-32 weeks birth gestational age) mother-infant pairs within 7-98 days postnatal age. Gastric samples were collected one, two and three hours after beginning of feeding. Samples were analysed for pH, proteolysis, general protease activity and the concentrations of pepsin, gastrin and gastrin-releasing peptide (GRP). One-way ANOVA with repeated measures followed by Tukey's multiple comparisons test was used. Gastric pH was significantly decreased after each hour in the preterm infant stomach from one to three hours postprandial. Proteolysis increased significantly from human milk to gastric contents at one, two and three hours postprandial (by 62, 131% and 181%, p milk to the gastric contents at two hours postprandial. GRP was present in human milk, whereas gastrin was produced in the infant stomach. Although preterm infants may digest human milk proteins to a lesser extent than term infants, we demonstrated that the preterm infant stomach actively degrades milk proteins with increasing breakdown over digestion time. ©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  14. Colloid straining within saturated heterogeneous porous media.

    Science.gov (United States)

    Porubcan, Alexis A; Xu, Shangping

    2011-02-01

    The transport of 0.46 μm, 2.94 μm, 5.1 μm and 6.06 μm latex particles in heterogeneous porous media prepared from the mixing of 0.78 mm, 0.46 mm and 0.23 mm quartz sands was investigated through column transport experiments. It was observed that the 0.46 μm particles traveled conservatively within the heterogeneous porous media, suggesting that under the experimental conditions employed in this research the strong repulsive interactions between the negatively charged latex particles and the clean quartz sands led to minimal colloid immobilization due to physicochemical filtration. The immobilization of the 2.94 μm, 5.1 μm and 6.06 μm latex particles was thus attributed to colloid straining. Experimental results showed that the straining of colloidal particles within heterogeneous sand mixtures increased when the fraction of finer sands increased. The mathematical model that was developed and tested based on results obtained using uniform sands (Xu et al., 2006) was found to be able to describe colloid straining within heterogeneous porous media. Examination of the relationship between the best-fit values of the clean-bed straining rate coefficients (k(0)) and the ratio of colloid diameter (d(p)) and sand grain size (d(g)) indicated that when number-average sizes were used to represent the size of the heterogeneous porous media, there existed a consistent relationship for both uniform sands and heterogeneous sand mixtures. Similarly, the use of the number-averaged sizes for the heterogeneous porous media produced a uniform relationship between the colloid straining capacity term (λ) and the ratio of d(p)/d(g) for all the sand treatments. © 2010 Elsevier Ltd. All rights reserved.

  15. Informal eldercare and work-related strain.

    Science.gov (United States)

    Trukeschitz, Birgit; Schneider, Ulrike; Mühlmann, Richard; Ponocny, Ivo

    2013-03-01

    In light of an aging workforce, reconciling informal eldercare and paid work becomes increasingly pertinent. This article investigates the association between informal eldercare and work-related strain and tests for both the "competing demands" and "expansion" hypotheses. The sample of 938 Austrian employees consisted of employees caring for older relatives and a control group of employees without eldercare obligations. We ran a Tobit regression model on work-related strain with different measures of informal eldercare as explanatory variables and controls for both personal and workplace characteristics. Accounting for different characteristics of eldercare within one estimation model revealed that informal eldercare was associated with work-related strain in 2 ways, that is, it increased with both care hours and subjective care burden. However, after controlling for these burdensome attributes of eldercare, the carer status as such was found to be negatively associated with work-related strain. In addition and independently of care commitments, work-related factors, such as advanced skills and job motivation, reduced work-related strain. This article lends support to both the "competing demands" and the "expansion" hypotheses. Commitment to eldercare can enhance work-related outcomes but entails work-related problems if care burden and time demands of eldercare are substantial. Thus, workers with eldercare responsibilities cannot be considered less productive from the outset. An individual assessment of their situation, considering the care and work setting, is required. Findings from this study support the design of workplace initiatives to uphold workers' productivity in general and bring specific attention to policies alleviating workers' eldercare burden.

  16. Electronic, mechanical and dielectric properties of silicane under tensile strain

    Energy Technology Data Exchange (ETDEWEB)

    Jamdagni, Pooja, E-mail: j.poojaa1228@gmail.com; Sharma, Munish; Ahluwalia, P. K. [Physics Department, Himachal Pradesh University, Shimla, Himachal Pradesh, India 171005 (India); Kumar, Ashok [Physics Department, Panjab University, Chandigarh, India, 160014 (India); Thakur, Anil [Physics Department, Govt. Collage Solan, Himachal Pradesh, India,173212 (India)

    2015-05-15

    The electronic, mechanical and dielectric properties of fully hydrogenated silicene i.e. silicane in stable configuration are studied by means of density functional theory based calculations. The band gap of silicane monolayer can be flexibly reduced to zero when subjected to bi-axial tensile strain, leading to semi-conducting to metallic transition, whereas the static dielectric constant for in-plane polarization increases monotonically with increasing strain. Also the EEL function show the red shift in resonance peak with tensile strain. Our results offer useful insight for the application of silicane monolayer in nano-optical and electronics devices.

  17. Electronic, mechanical and dielectric properties of silicane under tensile strain

    International Nuclear Information System (INIS)

    Jamdagni, Pooja; Sharma, Munish; Ahluwalia, P. K.; Kumar, Ashok; Thakur, Anil

    2015-01-01

    The electronic, mechanical and dielectric properties of fully hydrogenated silicene i.e. silicane in stable configuration are studied by means of density functional theory based calculations. The band gap of silicane monolayer can be flexibly reduced to zero when subjected to bi-axial tensile strain, leading to semi-conducting to metallic transition, whereas the static dielectric constant for in-plane polarization increases monotonically with increasing strain. Also the EEL function show the red shift in resonance peak with tensile strain. Our results offer useful insight for the application of silicane monolayer in nano-optical and electronics devices

  18. Strain gradients in epitaxial ferroelectrics

    International Nuclear Information System (INIS)

    Catalan, G.; Noheda, B.; McAneney, J.; Sinnamon, L.J.; Gregg, J.M.

    2005-01-01

    X-ray analysis of ferroelectric thin layers of Ba 1/2 Sr 1/2 TiO 3 with different thicknesses reveals the presence of strain gradients across the films and allows us to propose a functional form for the internal strain profile. We use this to calculate the influence of strain gradient, through flexoelectric coupling, on the degradation of the ferroelectric properties of films with decreasing thickness, in excellent agreement with the observed behavior. This paper shows that strain relaxation can lead to smooth, continuous gradients across hundreds of nanometers, and it highlights the pressing need to avoid such strain gradients in order to obtain ferroelectric films with bulklike properties

  19. A cell strain system for small homogeneous strain applications.

    Science.gov (United States)

    Bottlang, M; Simnacher, M; Schmitt, H; Brand, R A; Claes, L

    1997-11-01

    A cell culture system has been developed that enables application of well characterized, homogeneously distributed cyclic strains to monolayer cell cultures. Optically clear silicone culture dishes atop Plexiglas base plates are deformed by four-point bending of flexible silicone culture wells driven in user specified strain cycle patterns using computer controlled electromagnetic linear actuators. Cyclic mechano-transduction can be induced in amplitudes of 0 to 3000 mustrain, in frequencies of 0 to 30 Hz and in any specified strain cycle pattern. The cell culture system, which contains six simultaneously driven culture wells, has been mechanically characterized by holographic interferometry, laser displacement sensor recordings of the dish surfaces, strain gauge monitoring of the base plates, and finite element modeling of the dishes on the base plates. The standard deviation of the strain amplitudes among the six simultaneously stimulated culture wells is less than 5%. The cell culture system allows accurate generation of small magnitudes of well characterized, homogeneous strain, easy handling of the culture wells, flexible setting of cyclic strain pattern parameters, simultaneous stimulation of 6 culture wells, and light microscopic observation of the cell cultures.

  20. Strain expansion-reduction approach

    Science.gov (United States)

    Baqersad, Javad; Bharadwaj, Kedar

    2018-02-01

    Validating numerical models are one of the main aspects of engineering design. However, correlating million degrees of freedom of numerical models to the few degrees of freedom of test models is challenging. Reduction/expansion approaches have been traditionally used to match these degrees of freedom. However, the conventional reduction/expansion approaches are only limited to displacement, velocity or acceleration data. While in many cases only strain data are accessible (e.g. when a structure is monitored using strain-gages), the conventional approaches are not capable of expanding strain data. To bridge this gap, the current paper outlines a reduction/expansion technique to reduce/expand strain data. In the proposed approach, strain mode shapes of a structure are extracted using the finite element method or the digital image correlation technique. The strain mode shapes are used to generate a transformation matrix that can expand the limited set of measurement data. The proposed approach can be used to correlate experimental and analytical strain data. Furthermore, the proposed technique can be used to expand real-time operating data for structural health monitoring (SHM). In order to verify the accuracy of the approach, the proposed technique was used to expand the limited set of real-time operating data in a numerical model of a cantilever beam subjected to various types of excitations. The proposed technique was also applied to expand real-time operating data measured using a few strain gages mounted to an aluminum beam. It was shown that the proposed approach can effectively expand the strain data at limited locations to accurately predict the strain at locations where no sensors were placed.

  1. Antimicrobial resistance among Brazilian Corynebacterium diphtheriae strains

    Directory of Open Access Journals (Sweden)

    Gabriela Andrade Pereira

    2008-08-01

    Full Text Available The increasing problems with multidrug resistance in relation to Corynebacterium, including C. diphtheriae, are examples of challenges confronting many countries. For this reason, Brazilian C. diphtheriae strains were evaluated by the E-Test for their susceptibility to nine antibacterial drugs used in therapy. Resistance (MIC < 0.002; 0.38 µg/ml to penicillin G was found in 14.8% of the strains tested. Although erythromycin (MIC90 0.75 µg/ml and azithromycin (MIC90 0.064 µg/ml were active against C. diphtheriae in this study, 4.2% of the strains showed decreased susceptibility (MIC 1.0 µg/ml to erythromycin. Multiple resistance profiles were determined by the disk diffusion method using 31 antibiotics. Most C. diphtheriae strains (95.74% showed resistance to mupirocin, aztreonam, ceftazidime, and/or oxacillin, ampicillin, penicillin, tetracycline, clindamycin, lincomycin, and erythromycin. This study presents the antimicrobial susceptibility profiles of Brazilian C. diphtheriae isolates. The data are of value to practitioners, and suggest that some concern exists regarding the use of penicillin.

  2. Characterizing large strain crush response of redwood

    International Nuclear Information System (INIS)

    Cramer, S.M.; Hermanson, J.C.

    1996-12-01

    Containers for the transportation of hazardous and radioactive materials incorporate redwood in impact limiters. Redwood is an excellent energy absorber, but only the most rudimentary information exists on its crush properties. The objectives of the study were to fill the information gap by collecting triaxial load-deformation data for redwood; to use these data to characterize redwood crush, assess current wood failure theories, provide developments toward a complete stress-strain theory for redwood; and to review the literature on strain-rate effects on redwood crush performance. The load-deformation responses of redwood at temperature conditions corresponding to ambient (70 degrees F), 150 degrees F, and -20 degrees F conditions were measured in approximately 100 confined compression tests for crush levels leading to material densification. Data analysis provided a more complete description of redwood crush performance and a basis for assessing proposed general orthotropic stress-strain relationships for redwood. A review of existing literature indicated that strain-rate effects cause at most a 20 percent increase in crush stress parallel to grain

  3. Modulation of virulence and antibiotic susceptibility of enteropathogenic Escherichia coli strains by Enterococcus faecium probiotic strain culture fractions.

    Science.gov (United States)

    Ditu, Lia-Mara; Chifiriuc, Mariana Carmen; Bezirtzoglou, Eugenia; Voltsi, Chrysa; Bleotu, Coralia; Pelinescu, Diana; Mihaescu, Grigore; Lazar, Veronica

    2011-12-01

    The increasing rate of antimicrobial resistance drastically reduced the efficiency of conventional antibiotics and led to the reconsideration of the interspecies interactions in influencing bacterial virulence and response to therapy. The aim of the study was the investigation of the influence of the soluble and cellular fractions of Enterococcus (E.) faecium CMGB16 probiotic culture on the virulence and antibiotic resistance markers expression in clinical enteropathogenic Escherichia (E.) coli strains. The 7 clinical enteropathogenic E. coli strains, one standard E. coli ATCC 25,922 and one Bacillus (B.) cereus strains were cultivated in nutrient broth, aerobically at 37 °C, for 24 h. The E. faecium CMGB16 probiotic strain was cultivated in anaerobic conditions, at 37 °C in MRS (Man Rogosa Sharpe) broth, and co-cultivated with two pathogenic strains (B. cereus and E. coli O28) culture fractions (supernatant, washed sediment and heat-inactivated culture) for 6 h, at 37 °C. After co-cultivation, the soluble and cellular fractions of the probiotic strain cultivated in the presence of two pathogenic strains were separated by centrifugation (6000 rpm, 10 min), heat-inactivated (15 min, 100 °C) and co-cultivated with the clinical enteropathogenic E. coli strains in McConkey broth, for 24 h, at 37 °C, in order to investigate the influence of the probiotic fractions on the adherence capacity and antibiotic susceptibility. All tested probiotic combinations influenced the adherence pattern of E. coli tested strains. The enteropathogenic E. coli strains susceptibility to aminoglycosides, beta-lactams and quinolones was increased by all probiotic combinations and decreased for amoxicillin-clavulanic acid. This study demonstrates that the plurifactorial anti-infective action of probiotics is also due to the modulation of virulence factors and antibiotic susceptibility expression in E. coli pathogenic strains. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Effects of strain and strain-induced α'-martensite on passive films in AISI 304 austenitic stainless steel.

    Science.gov (United States)

    Lv, Jinlong; Luo, Hongyun

    2014-01-01

    In this paper, the effects of strain and heat treatment on strain-induced α'-martensite of AISI 304 stainless steel tubes were measured by X-ray diffraction. Moreover, the effects of strain and content of α'-martensite on passivated property on the surface of the material in borate buffer solution were evaluated by electrochemical technique. The results showed that the volume fraction of α'-martensite increased gradually with the increase of tensile strain for as-received and solid solution samples. However, α'-martensite in as-received sample was more than that in the solid solution sample. The electrochemical impedance spectroscopy results showed that the solid solution treatment improved corrosion resistance of the steel, especially for samples with small strain. Moreover, acceptor densities were always higher than donor densities for as-received and solid solution samples. With the increase of strain, the increase tendency of acceptor density was more significant than that of donor density. We also found that the total density of the acceptor and donor almost increased linearly with the increase of α'-martensite. The present results indicated that the increased acceptor density might lead to the decreased corrosion resistance of the steel. © 2013.

  5. Inactivated Tianjin strain, a novel genotype of Sendai virus, induces apoptosis in HeLa, NCI-H446 and Hep3B cells.

    Science.gov (United States)

    Chen, Jun; Han, Han; Wang, Bin; Shi, Liying

    2016-07-01

    The Sendai virus strain Tianjin is a novel genotype of the Sendai virus. In previous studies, ultraviolet-inactivated Sendai virus strain Tianjin (UV-Tianjin) demonstrated antitumor effects on human breast cancer cells. The aim of the present study was to investigate the in vitro antitumor effects of UV-Tianjin on the human cervical carcinoma HeLa, human small cell lung cancer NCI-H446 and human hepatocellular carcinoma Hep 3B cell lines, and the possible underlying mechanisms of these antitumor effects. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay revealed that UV-Tianjin treatment inhibited the proliferation of HeLa, NCI-H446 and Hep 3B cells in a dose- and time-dependent manner. Hoechst and Annexin V-fluorescein isothiocyanate/propidium iodide double staining indicated that UV-Tianjin induced dose-dependent apoptosis in all three cell lines with the most significant effect observed in the HeLa cell line. In the HeLa cell line, UV-Tianjin-induced apoptosis was further confirmed by the disruption of the mitochondria membrane potential and the activation of caspases, as demonstrated by fluorescent cationic dye and colorimetric assays, respectively. In addition, western blot analysis revealed that UV-Tianjin treatment resulted in significant upregulation of cytochrome c , apoptosis protease activating factor-1, Fas, Fas ligand and Fas-associated protein with death domain, and activated caspase-9, -8 and -3 in HeLa cells. Based on these results, it is hypothesized that UV-Tianjin exhibits anticancer activity in HeLa, NCI-H446 and Hep 3B cell lines via the induction of apoptosis. In conclusion, the results of the present study indicate that in the HeLa cell line, intrinsic and extrinsic apoptotic pathways may be involved in UV-Tianjin-induced apoptosis.

  6. In vitro determination of the antibiotic susceptibility of biofilm-forming Pseudomonas aeruginosa and Staphylococcus aureus: possible role of proteolytic activity and membrane lipopolysaccharide.

    Science.gov (United States)

    Masadeh, Majed M; Mhaidat, Nizar M; Alzoubi, Karem H; Hussein, Emad I; Al-Trad, Esra'a I

    2013-01-01

    We carried out a comprehensive overview of inhibitory effects of selected antibiotics on planktonic and biofilm cells of Staphylococcus aureus (ATCC 29213) and Pseudomonas aeruginosa (ATCC 27853) strains. The possible involvement of protease activity and the lipopolysaccharide (LPS) profile of P. aeruginosa were also analyzed. Biofilm cells of both strains were more resistant to antibiotics than their planktonic counterparts. Protease activity was increased in both strains in the biofilm forms. Challenge with sublethal doses of antibiotics also increased proteolytic activity of biofilm cells. Additionally, the LPS profile of P. aeruginosa showed pattern alterations of the biofilm that can contribute to biofilm resistance and survival. These observations provide evidence for the involvement of bacterial proteolytic activity and LPS profile in the resistance of biofilm bacteria to antibiotics compared to their planktonic counterparts.

  7. Consumer perceptions of strain differences in Cannabis aroma.

    Science.gov (United States)

    Gilbert, Avery N; DiVerdi, Joseph A

    2018-01-01

    The smell of marijuana (Cannabis sativa L.) is of interest to users, growers, plant breeders, law enforcement and, increasingly, to state-licensed retail businesses. The numerous varieties and strains of Cannabis produce strikingly different scents but to date there have been few, if any, attempts to quantify these olfactory profiles directly. Using standard sensory evaluation techniques with untrained consumers we have validated a preliminary olfactory lexicon for dried cannabis flower, and characterized the aroma profile of eleven strains sold in the legal recreational market in Colorado. We show that consumers perceive differences among strains, that the strains form distinct clusters based on odor similarity, and that strain aroma profiles are linked to perceptions of potency, price, and smoking interest.

  8. Construction of acetoin high-producing Bacillus subtilis strain

    Directory of Open Access Journals (Sweden)

    Yanjun Tian

    2016-07-01

    Full Text Available This paper describes the construction and selection of a high-producing mutant, Bacillus subtilis HB-32, with enhanced acetoin yield and productivity. The mutant was obtained by the protoplast fusion of a Bacillus subtilis mutant TH-49 (Val− producing acetoin and Bacillus licheniformis AD-30 producing α-acetolactate decarboxylase, with the fusogen polyethylene glycol and after the regeneration and selection, etc. of the fusant. The acetoin production reached 49.64 g/L, which is an increase of 61.8% compared to that of B. subtilis strain TH-49. Random amplified polymorphic DNA analysis was performed to determine the mutagenic and protoplast fusion effects and the genomic changes in the acetoin high-producing strain compared to the parent strains at the molecular level. The constructed strain was shown to be promising for large-scale acetoin production. Future studies should focus on the application of the mutant strain in practice.

  9. Undergraduate Prescription Stimulant Misuse: The Impact of Academic Strain.

    Science.gov (United States)

    Norman, Lauren; Ford, Jason

    2018-01-09

    This study investigated the misuse of prescription stimulants among undergraduates for academic purposes. This research is important as existing literature has indicated that this type of prescription drug misuse is a growing concern, especially among college undergraduates aged 18-25. This study focused on how various types of academic strain (i.e., academic strain, grade strain, and academic impediments) influenced the misuse of prescription stimulants. Roughly 900 quantitative surveys were collected at a large Southeastern university in May 2014 that specifically addressed prescription stimulant misuse. Results from regression analyses indicated that college students are at an increased likelihood of misusing prescription stimulants for academic purposes if they experienced academic impediments and/or grade strain during the past academic year. Conclusions/Importance: It is necessary to identify how academic strain impacts undergraduates' likelihood of engaging in the misuse of prescription stimulants as this information may aid in college based educational and prevention programs.

  10. Parallel Microcracks-based Ultrasensitive and Highly Stretchable Strain Sensors.

    Science.gov (United States)

    Amjadi, Morteza; Turan, Mehmet; Clementson, Cameron P; Sitti, Metin

    2016-03-02

    There is an increasing demand for flexible, skin-attachable, and wearable strain sensors due to their various potential applications. However, achieving strain sensors with both high sensitivity and high stretchability is still a grand challenge. Here, we propose highly sensitive and stretchable strain sensors based on the reversible microcrack formation in composite thin films. Controllable parallel microcracks are generated in graphite thin films coated on elastomer films. Sensors made of graphite thin films with short microcracks possess high gauge factors (maximum value of 522.6) and stretchability (ε ≥ 50%), whereas sensors with long microcracks show ultrahigh sensitivity (maximum value of 11,344) with limited stretchability (ε ≤ 50%). We demonstrate the high performance strain sensing of our sensors in both small and large strain sensing applications such as human physiological activity recognition, human body large motion capturing, vibration detection, pressure sensing, and soft robotics.

  11. Strain Rate Effects in CFRP Used For Blast Mitigation

    Directory of Open Access Journals (Sweden)

    Sarah. L. Orton

    2014-04-01

    Full Text Available The purpose of this research is to gain a better understanding of strain rate effects in carbon fiber reinforced polymer (CFRP laminates exposed to blast loading. The use of CFRP offers an attractive option for mitigating structures exposed to blasts. However, the effect of high strain rates in CFRP composites commonly used in the civil industry is unknown. This research conducted tensile tests of 21 CFRP coupons using a hydraulically powered dynamic loader. The strain rates ranged from 0.0015 s−1 to 7.86 s−1 and are representative of strain rates that CFRP may see in a blast when used to strengthen reinforced concrete structures. The results of the testing showed no increase in the tensile strength or stiffness of the CFRP at the higher strain rates. In addition, the results showed significant scatter in the tensile strengths possibly due to the rate of loading or manufacture of the coupon.

  12. Consumer perceptions of strain differences in Cannabis aroma.

    Directory of Open Access Journals (Sweden)

    Avery N Gilbert

    Full Text Available The smell of marijuana (Cannabis sativa L. is of interest to users, growers, plant breeders, law enforcement and, increasingly, to state-licensed retail businesses. The numerous varieties and strains of Cannabis produce strikingly different scents but to date there have been few, if any, attempts to quantify these olfactory profiles directly. Using standard sensory evaluation techniques with untrained consumers we have validated a preliminary olfactory lexicon for dried cannabis flower, and characterized the aroma profile of eleven strains sold in the legal recreational market in Colorado. We show that consumers perceive differences among strains, that the strains form distinct clusters based on odor similarity, and that strain aroma profiles are linked to perceptions of potency, price, and smoking interest.

  13. Effect of pressurization on antibacterial properties of Lactobacillus strains

    Science.gov (United States)

    Jankowska, Agnieszka; Grześkiewicz, Aleksandra; Wiśniewska, Krystyna; Reps, Arnold

    2010-03-01

    The objective of the study was to determine the effect of high pressures on antibacterial properties of selected strains of the Lactobacillus species. Cultures of 22 strains were subjected to high-pressure treatment at 30, 60, 90, and 300 MPa/1 min/18 °C. The susceptibility of the bacteria pressurized at 30-90 MPa was diversified and depended on the strain and not on its species affiliation. When compared with pressures of 30-90 MPa, the pressure treatment at 300 MPa caused the inhibition of the acidifying activity of the strains analyzed. In turn, the pressures applied had no impact on the quantity of hydrogen peroxide synthesized. An increase in pressure was accompanied by a diminishing antibacterial activity of the investigated Lactobacillus strains.

  14. Electronic properties of polycrystalline graphene under large local strain

    International Nuclear Information System (INIS)

    He, Xin; Tang, Ning; Duan, Junxi; Mei, Fuhong; Meng, Hu; Lu, Fangchao; Xu, Fujun; Yang, Xuelin; Gao, Li; Wang, Xinqiang; Shen, Bo; Ge, Weikun

    2014-01-01

    To explore the transport properties of polycrystalline graphene under large tensile strain, a strain device has been fabricated using piezocrystal to load local strain onto graphene, up to 22.5%. Ionic liquid gate whose capability of tuning carrier density being much higher than that of a solid gate is used to survey the transfer characteristics of the deformed graphene. The conductance of the Dirac point and field effect mobility of electrons and holes is found to decrease with increasing strain, which is attributed to the scattering of the graphene grain boundaries, the strain induced change of band structure, and defects. However, the transport gap is still not opened. Our study is helpful to evaluate the application of graphene in stretchable electronics.

  15. Enzymes From Rare Actinobacterial Strains.

    Science.gov (United States)

    Suriya, J; Bharathiraja, S; Manivasagan, P; Kim, S-K

    Actinobacteria constitute rich sources of novel biocatalysts and novel natural products for medical and industrial utilization. Although actinobacteria are potential source of economically important enzymes, the isolation and culturing are somewhat tough because of its extreme habitats. But now-a-days, the rate of discovery of novel compounds producing actinomycetes from soil, freshwater, and marine ecosystem has increased much through the developed culturing and genetic engineering techniques. Actinobacteria are well-known source of their bioactive compounds and they are the promising source of broad range of industrially important enzymes. The bacteria have the capability to degrade a range of pesticides, hydrocarbons, aromatic, and aliphatic compounds (Sambasiva Rao, Tripathy, Mahalaxmi, & Prakasham, 2012). Most of the enzymes are mainly derived from microorganisms because of their easy of growth, minimal nutritional requirements, and low-cost for downstream processing. The focus of this review is about the new, commercially useful enzymes from rare actinobacterial strains. Industrial requirements are now fulfilled by the novel actinobacterial enzymes which assist the effective production. Oxidative enzymes, lignocellulolytic enzymes, extremozymes, and clinically useful enzymes are often utilized in many industrial processes because of their ability to catalyze numerous reactions. Novel, extremophilic, oxidative, lignocellulolytic, and industrially important enzymes from rare Actinobacterial population are discussed in this chapter. © 2016 Elsevier Inc. All rights reserved.

  16. Strain fluctuations and elastic constants

    Energy Technology Data Exchange (ETDEWEB)

    Parrinello, M.; Rahman, A.

    1982-03-01

    It is shown that the elastic strain fluctuations are a direct measure of elastic compliances in a general anisotropic medium; depending on the ensemble in which the fluctuation is measured either the isothermal or the adiabatic compliances are obtained. These fluctuations can now be calculated in a constant enthalpy and pressure, and hence, constant entropy, ensemble due to recent develpments in the molecular dynamics techniques. A calculation for a Ni single crystal under uniform uniaxial 100 tensile or compressive load is presented as an illustration of the relationships derived between various strain fluctuations and the elastic modulii. The Born stability criteria and the behavior of strain fluctuations are shown to be related.

  17. Strain accumulation in quasicrystalline solids

    International Nuclear Information System (INIS)

    Nori, F.; Ronchetti, M.; Elser, V.

    1988-01-01

    We study the relaxation of 2D quasicrystalline elastic networks when their constituent bonds are perturbed homogeneously. Whereas ideal, quasiperiodic networks are stable against such perturbations, we find significant accumulations of strain in a class of disordered networks generated by a growth process. The grown networks are characterized by root mean square phason fluctuations which grow linearly with system size. The strain accumulation we observe in these networks also grows linearly with system size. Finally, we find a dependence of strain accumulation on cooling rate

  18. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right...... of the cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained...

  19. Strain rate effects for spallation of concrete

    Directory of Open Access Journals (Sweden)

    Häussler-Combe Ulrich

    2015-01-01

    Full Text Available Appropriate triaxial constitutive laws are the key for a realistic simulation of high speed dynamics of concrete. The strain rate effect is still an open issue within this context. In particular the question whether it is a material property – which can be covered by rate dependent stress strain relations – or mainly an effect of inertia is still under discussion. Experimental and theoretical investigations of spallation of concrete specimen in a Hopkinson Bar setup may bring some evidence into this question. For this purpose the paper describes the VERD model, a newly developed constitutive law for concrete based on a damage approach with included strain rate effects [1]. In contrast to other approaches the dynamic strength increase is not directly coupled to strain rate values but related to physical mechanisms like the retarded movement of water in capillary systems and delayed microcracking. The constitutive law is fully triaxial and implemented into explicit finite element codes for the investigation of a wide range of concrete structures exposed to impact and explosions. The current setup models spallation experiments with concrete specimen [2]. The results of such experiments are mainly related to the dynamic tensile strength and the crack energy of concrete which may be derived from, e.g., the velocity of spalled concrete fragments. The experimental results are compared to the VERD model and two further constitutive laws implemented in LS-Dyna. The results indicate that both viscosity and retarded damage are required for a realistic description of the material behaviour of concrete exposed to high strain effects [3].

  20. X-ray determination of crystallite size and effect of lattice strain on ...

    Indian Academy of Sciences (India)

    ... the half-widths and integrated intensities of the Bragg reflections. In Pt, the Debye–Waller factor is found to increase with lattice strain. From the correlation between the strain and effective Debye–Waller factor, the Debye–Waller factors for zero strain have been estimated for Pt. The variation of energy of vacancy formation ...

  1. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.

    2016-01-01

    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress...... fibre tends to increase the strain, stress and force sensitivity of the photo-inscribed sensor....

  2. Nickel--chromium strain gages for cryogenic stress analysis of superconducting structures in high magnetic fields

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Magnetoresistance measurements of strain gages were made. The magnitude and variation of the magnetoresistance of a large number of strain gages were measured for the following conditions: (1) dc magnetic fields up to 12 T, (2) three orthogonal field directions, (3) increasing and decreasing fields, (4) a wide range of strain levels, and (5) liquid helium temperature

  3. Strain engineering the work function in monolayer metal dichalcogenides

    International Nuclear Information System (INIS)

    Lanzillo, Nicholas A; Simbeck, Adam J; Nayak, Saroj K

    2015-01-01

    We use first-principles density functional theory to investigate the effect of both tensile and compressive strain on the work functions of various metal dichalcogenide monolayers. We find that for all six species considered, including MoS 2 , WS 2 , SnS 2 , VS 2 , MoSe 2 and MoTe 2 , that compressive strain of up to 10% decreases the work function continuously by as much as 1.0 eV. Large enough tensile strain is also found to decrease the work function, although in some cases we observe an increase in the work function for intermediate values of tensile strain. This work function modulation is attributed to a weakening of the chalcogenide-metal bonds and an increase in total energy of each system as a function of strain. Values of strain which bring the metal atoms closer together lead to an increase in electrostatic potential energy, which in turn results in an increase in the vacuum potential level. The net effect on the work function can be explained in terms of the balance between the increases in the vacuum potential levels and Fermi energy. (paper)

  4. Ductility of aluminium alloy AA7075 at high strain rates

    Energy Technology Data Exchange (ETDEWEB)

    El-Magd, E.; Brodmann, M. [Technische Hochschule Aachen (Germany). Dept. of Mater. Sci.

    2000-09-01

    Under dynamic loading the stabilising effect of increased strain rate sensitivity of the material restrains neck formation in tension tests and leads to an increase in ductility. On the other hand the adiabatic character of the deformation process reduces the flow stress and promotes instability, localisation and adiabatic shear band initiation. Furthermore, the notch sensitivity of the material increases with increasing strain rate. Dynamic and quasi-static tension and compression tests were carried out on the age hardenable aluminium wrought alloy AA7075. There, dispers distributed precipitations are often the starting point for ductile fracture caused by impact due to the nucleation, growth and coalescence of voids and micro-cracks in case of tension. Neck formation under tensile loading and instabilities like shear bands in case of compression are discussed on the basis of the theory of imperfection under consideration of the increased strain rate sensitivity of the material and the adiabatic character of the deformation process at high strain rates. In case of tensile loading, tests with various notched geometries allowed the study of the influence of degree of multiaxiality. Through combination of experiment and simulation, the influence of strain rate on the local fracture strain could be determined for tensile and compression loading. (orig.)

  5. Impact of SEG on uniaxially strained MuGFET performance

    Science.gov (United States)

    Agopian, Paula Ghedini Der; Pacheco, Vinícius Heltai; Martino, João Antonio; Simoen, Eddy; Claeys, Cor

    2011-05-01

    This work focuses on the impact of the source and drain Selective Epitaxial Growth (SEG) on the performance of uniaxially strained MuGFETs. With the channel length reduction, the normalized transconductance (gm. L/ W) of unstressed MuGFETs decreases due to the series resistance and short channel effects (SCE), while the presence of uniaxial strain improves the gm. The competition between the series resistance ( Rs) and the uniaxial strain results in a normalized gm maximum point for a specific channel length. Since the SEG structure influences both Rs and the strain in the channel, this work studies from room down to low temperature how these effects influence the performance of the triple-gate FETs. For lower temperatures, the strain-induced mobility enhancement increases and leads to a shift in the maximum point towards shorter channel lengths for devices without SEG. This shift is not observed for devices with SEG where the strain level is much lower. At 150 K the gm behavior of short channel strained devices with SEG is similar to the non SEG ones due to the better gm temperature enhancement for devices without SEG caused by the strain. For lower temperatures SEG structure is not useful anymore.

  6. PROPERTIES OF NEW STRAINS CHEMOLITHOTROPHIC BACTERIA ISOLATED FROM INDUSTRIAL SUBSTRATES

    Directory of Open Access Journals (Sweden)

    I. A.

    2015-12-01

    Full Text Available The purpose of the research was determination of strains Acidithiobacillus ferrooxidans MFLv37 and Acidithiobacillus ferrooxidans MFLad27, isolated from aboriginal consortium of coal beneficiation dumps and fly ash from coal combustion, resistance to heavy metals, forming part of these waste, as well as adaption ability of the strains to new substrates. New strains increased resistance to heavy metal ions as compared to A. ferrooxidans standard and collection strains is found; minimal inhibitory concentrations of heavy and toxic metals are determined; a number of metals that have negative impact on growth of isolated cultures are identified. It is shown that the minimal metals concentrations, at which strains growth still happens, are several times higher than their concentrations in technogenic waste. It has been established that isolated strains differed in their ability to adapt, as well as in growth rate and substrates oxidation. This is due to the specific conditions of microbiocenoses formation in making and further storage of rock dumps and fly ash, whereof the appropriate strains are isolated. The investigations indicate the necessity in directional selection of strains that are resistant to the toxic compounds and are able to oxidize various mineral substrates, as well as in their adaptation to new substrates for the extraction of heavy metals.

  7. Effect of plastic strain on elastic-plastic fracture toughness of SM490 carbon steel

    International Nuclear Information System (INIS)

    Kamaya, Masayuki

    2010-01-01

    Although the plastic strain induced in materials increases the mechanical strength, it may reduce the fracture toughness. The change in the fracture toughness is brought about by four factors; reduction in critical plastic strain due to pre-strain, localization of deformation, increase of material strength by work hardening, and change in material resistance for fracture. In this study, correlation between change in fracture toughness by pre-strain and the four factors was investigated. Firstly, the change in the tensile properties and fracture toughness were examined for pre-strained SM490 carbon steel. The specimens with blunt notch of 0.2 mm and 0.4 mm radius were used in addition to those with conventional fatigue pre-cracking. The degree of applied plastic strain was 5%, 10% and 20%. The fracture toughness was largest when the induced plastic strain was 5%, although it decreased in the cases for the plastic strain of 10% and 20%. Secondly, the stress and strain field near notch tip was evaluated by simulating the experiment using elastic-plastic finite element analyses. It was concluded that the change in fracture toughness was mainly brought about by the change in material resistance caused by the plastic strain. Under the plastic strain of 10% and 20%, the critical plastic strain for crack initiation decreased due to change in material resistance in addition to apparent reduction by pre-straining. The localized deformation and work hardening had minor effect on the change in fracture toughness. (author)

  8. Strains and Sprains

    Science.gov (United States)

    ... Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Drugs & Alcohol School & Jobs Sports Expert Answers (Q&A) Staying Safe Videos for ... limb that looks "bent" or misshapen signs of infection (increased warmth, redness, ... in any sport, and make sure they always wear appropriate protective ...

  9. Strain localisation in granular media

    OpenAIRE

    Desrues , Jacques

    1984-01-01

    This study is devoted to strain localisation in Granular materials. Both experimental and theoretical results have been obtained.The first part of the thesis is a review of the methods and theories about rupture in sols mechanics and more generally, in solid mechanics. The classical framework of Shear Band analysis is presented, and the main results available for different classes of materials are discussed.The second part describes an experimental study of strain localisation in sand specime...

  10. Global Strain in Severe Aortic Valve Stenosis

    DEFF Research Database (Denmark)

    Dahl, Jordi S; Videbæk, Lars; Poulsen, Mikael K

    2012-01-01

    BACKGROUND: -Global longitudinal systolic strain (GLS) is often reduced in aortic stenosis despite normal ejection fraction. The importance of reduced preoperative GLS on long-term outcome after aortic valve replacement (AVR) is unknown. METHODS AND RESULTS: -A total of 125 patients with severe...... quartile 49% (n=15), p=0.04. Patients with increased age, left ventricular hypertrophy and left atrial dilatation were at increased risk. In Cox regression analysis after correcting for standard risk factors and ejection fraction, GLS was found to be significantly associated with cardiac morbidity...

  11. Organic chemistry. Strain-release amination.

    Science.gov (United States)

    Gianatassio, Ryan; Lopchuk, Justin M; Wang, Jie; Pan, Chung-Mao; Malins, Lara R; Prieto, Liher; Brandt, Thomas A; Collins, Michael R; Gallego, Gary M; Sach, Neal W; Spangler, Jillian E; Zhu, Huichin; Zhu, Jinjiang; Baran, Phil S

    2016-01-15

    To optimize drug candidates, modern medicinal chemists are increasingly turning to an unconventional structural motif: small, strained ring systems. However, the difficulty of introducing substituents such as bicyclo[1.1.1]pentanes, azetidines, or cyclobutanes often outweighs the challenge of synthesizing the parent scaffold itself. Thus, there is an urgent need for general methods to rapidly and directly append such groups onto core scaffolds. Here we report a general strategy to harness the embedded potential energy of effectively spring-loaded C-C and C-N bonds with the most oft-encountered nucleophiles in pharmaceutical chemistry, amines. Strain-release amination can diversify a range of substrates with a multitude of desirable bioisosteres at both the early and late stages of a synthesis. The technique has also been applied to peptide labeling and bioconjugation. Copyright © 2016, American Association for the Advancement of Science.

  12. Transfer induced compressive strain in graphene

    DEFF Research Database (Denmark)

    Larsen, Martin Benjamin Barbour Spanget; Mackenzie, David; Caridad, Jose

    2014-01-01

    We have used spatially resolved micro Raman spectroscopy to map the full width at half maximum (FWHM) of the graphene G-band and the 2D and G peak positions, for as-grown graphene on copper catalyst layers, for transferred CVD graphene and for micromechanically exfoliated graphene, in order...... to characterize the effects of a transfer process on graphene properties. Here we use the FWHM(G) as an indicator of the doping level of graphene, and the ratio of the shifts in the 2D and G bands as an indicator of strain. We find that the transfer process introduces an isotropic, spatially uniform, compressive...... strain in graphene, and increases the carrier concentration....

  13. Relation between job strain and myocardial infarction

    DEFF Research Database (Denmark)

    Netterstrøm, B; Nielsen, F E; Kristensen, T S

    1999-01-01

    OBJECTIVES: To study the influence of different job related and socioeconomic factors for development of myocardial infarction (MI). METHOD: The study was a case-control study of 76 male wage earners who had been admitted to hospital with MI. As a control group 176 male wage earners not admitted...... to hospital who were residents of the same county were used. Both groups were interviewed with an extensive questionnaire on job related conditions. Several indices on job related psychosocial factors were established in accordance with Karasek's job strain model as well as the extension of the model......, the isostrain model. RESULTS: The most significant findings were consistent with Karasek's job strain model in that mean with a high degree of demand combined with a low degree of control at work had a significantly increased odds ratio (OR) 95% confidence interval (95% CI) of 2.1 (1.2 to 3.8) for MI after...

  14. Extracellular Signals of a Human Epithelial Colorectal Adenocarcinoma (Caco-2) Cell Line Facilitate the Penetration of Pseudomonas aeruginosa PAO1 Strain through the Mucin Layer

    Science.gov (United States)

    Hayashi, Naoki; Yokotani, Atsushi; Yamamoto, Masami; Kososhi, Mariko; Morita, Mayu; Fukunishi, Chiaki; Nishizawa, Nagisa; Gotoh, Naomasa

    2017-01-01

    Pseudomonas aeruginosa can penetrate the layer of mucus formed by host intestinal epithelial cells, often resulting in sepsis in immunocompromised patients. We have previously demonstrated that P. aeruginosa can penetrate the mucin layer by flagellar motility and the degradation of the mucin layer. However, it remains unclear how P. aeruginosa initially recognizes epithelial cells. Using the human epithelial colorectal adenocarcinoma (Caco-2) cell line, we investigated extracellular signaling that could facilitate the penetration of P. aeruginosa through the mucin layer. The supernatant from Caco-2 cell cultures increased penetration of P. aeruginosa through an artificial mucin layer. The Caco-2 cell supernatant increased bacterial flagella-dependent swarming motility, but it did not influence P. aeruginosa growth or protease activity. Filtering of the Caco-2 cell supernatant indicated that proteins weighing Caco-2 cell supernatant attracted P. aeruginosa cells. Finally, we identified that growth-regulated oncogene-α (GRO-α) secreted by Caco-2 cells was a factor facilitating flagellar filament rotation and swarming motility, although it did not attract the bacteria. We conclude that penetration of the mucin layer by P. aeruginosa is facilitated by small proteins (Caco-2 cells, both by inducing acceleration of flagellar motility and increasing chemotaxis. PMID:28983473

  15. Note on Strain Release Variation with Depth

    Directory of Open Access Journals (Sweden)

    A. G. GALANOPOULOS

    1964-06-01

    Full Text Available In the present paper an attempt is made to approach
    the problem of the upper mantle structure by studying the strain relea.se
    variation with depth. If the method and data used in this paper are adequate,
    we may be allowed to say that although there is no strain release
    evidence for the depth of the upper boundary of the asthenospliere zone on
    account of lack of adequate accuracy in the determination of focal depths,
    nevertheless there is ample indication of a discontinuity at about 125 km
    depth. The abrupt change in the rate of decrease in the strain release
    with depth near this level clearly indicates that a sudden decrease in the
    yield strength of the material in the earth should occur at about this depth.
    I t might even be possible to think that the melting point of some kind of
    crystal grains or rocks in the earth is attained at that depth. However,
    this does not involve a completely molten state. This state should rather
    occur at depths where there is a complete lack of strain release. Regionally
    this state is attained at different depths, but in some regions the partially
    molten state, i. e. the heterogeneity of the mantle, probably recurs or increases
    due to the pressure increase or some other reason and reaches a minor
    maximum beyond which it might be possible to speculate that the heterogeneity
    of the mantle falls off rapidly and a continuous layer of material
    in molten state covers the whole earth. If data from other sources will
    confirm this structure, there will be good reasons to think of redefining
    the upper boundaries of surface and intermediate shocks at depths of 125
    and 425 km or thereabouts, respectively.

  16. Embedded silicon nanocrystal interface structure and strain

    Science.gov (United States)

    Shenoy, Bhamy Maithry; Hegde, G. M.; Mahapatra, D. Roy

    2018-01-01

    The structure of nanocrystal-matrix interface and strain in embedded nanocrystals are studied using large-scale atomistic simulations, with the examples of Si nanocrystal embedded in amorphous matrix of SiO2. Photoluminescence from silicon nanocrystals embedded in a dielectric matrix like SiO2 and Si3N4 are promising for Si-based optical devices. The nanocrystal-matrix interface plays a crucial role in understanding its optical and electrical properties. Nanocrystals with diameters varying from 2.17 to 4.56 nm are studied. A detailed quantitative analysis of the variation of Si/SiO2 interface structure and strain distribution with nanocrystal diameter is reported. A linear variation of the interface width with nanocrystal diameter is observed with thinner interfaces for larger nanocrystals. Local deformation analysis reveals that the smaller nanocrystals are highly strained, whereas the strain in the larger ones shifts to the interface. This is in accordance with observed increase in total percentage of defect states in the interface from 39 to 70 % for diameter increasing from 2.17 to 4.56 nm. Moreover, based on the atomic arrangements at the interface, optically active defects like Pb centres, E centres and non-bridging oxygen centres are identified and a dominance of Pb centres is observed for all the nanocrystals. The detailed structural characterization-related investigations using the proposed simulation approach will find useful application in designing system-level response of embedded nanocrystals and also to correlate various experimental observations.

  17. Complex strain paths in polycrystalline copper: microstructural aspects

    Directory of Open Access Journals (Sweden)

    M.F. Vieira

    1999-07-01

    Full Text Available Microstructural aspects of polycrystalline copper sheets subjected to complex strain paths were analysed in this work. Dislocation structures developed during the strain paths (rolling and tension and the evolution of this microstructure during reloading have been studied. The active slip systems developed in each strain path were used to explain the microstructural evolution. The heterogeneous surface deformation observed on polished tensile specimens prestrained in rolling was also analysed. The structural aspects are related with the mechanical behaviour of the material, namely with the increase in yield stress in reloading, the work hardening evolution and the premature occurrence of plastic instability for some prestrain values.

  18. Effect of lattice strain on the electro-catalytic activity of IrO2for water splitting.

    Science.gov (United States)

    Sun, Wei; Wang, Zhiqiang; Zaman, Waqas Qamar; Zhou, Zhenhua; Cao, Limei; Gong, Xue-Qing; Yang, Ji

    2018-01-23

    The lattice strain of IrO 2 plays a critical role in determining its OER activity. The Ir-O bond length change in IrO 6 coordination induces lattice strain. Increasing the annealing temperature results in a stretching strain along the c axis and a compressive strain on the a and b axes, leading to a larger c/a ratio. Enhancing the lattice strain decreases the c/a ratio, which is beneficial for improving OER activity.

  19. Dual-phase cardiac diffusion tensor imaging with strain correction.

    Directory of Open Access Journals (Sweden)

    Christian T Stoeck

    Full Text Available In this work we present a dual-phase diffusion tensor imaging (DTI technique that incorporates a correction scheme for the cardiac material strain, based on 3D myocardial tagging.In vivo dual-phase cardiac DTI with a stimulated echo approach and 3D tagging was performed in 10 healthy volunteers. The time course of material strain was estimated from the tagging data and used to correct for strain effects in the diffusion weighted acquisition. Mean diffusivity, fractional anisotropy, helix, transverse and sheet angles were calculated and compared between systole and diastole, with and without strain correction. Data acquired at the systolic sweet spot, where the effects of strain are eliminated, served as a reference.The impact of strain correction on helix angle was small. However, large differences were observed in the transverse and sheet angle values, with and without strain correction. The standard deviation of systolic transverse angles was significantly reduced from 35.9±3.9° to 27.8°±3.5° (p<0.001 upon strain-correction indicating more coherent fiber tracks after correction. Myocyte aggregate structure was aligned more longitudinally in systole compared to diastole as reflected by an increased transmural range of helix angles (71.8°±3.9° systole vs. 55.6°±5.6°, p<0.001 diastole. While diastolic sheet angle histograms had dominant counts at high sheet angle values, systolic histograms showed lower sheet angle values indicating a reorientation of myocyte sheets during contraction.An approach for dual-phase cardiac DTI with correction for material strain has been successfully implemented. This technique allows assessing dynamic changes in myofiber architecture between systole and diastole, and emphasizes the need for strain correction when sheet architecture in the heart is imaged with a stimulated echo approach.

  20. Effects of C and Si on strain aging of strain-based API X60 pipeline steels

    Science.gov (United States)

    Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Lee, Byeong-Joo; Hong, Seung-Pyo; Kim, Young-Woon; Yoo, Jang Yong; Hwang, Byoungchul; Shin, Sang Yong

    2017-05-01

    Four types of strain-based API X60 pipeline steels were fabricated by varying the C and Si contents, and the effects of C and Si on strain aging were investigated. The 0.05 wt% C steels consisted mainly of polygonal ferrite (PF), whereas the 0.08 wt% C steels consisted of acicular ferrite (AF). The volume fraction of AF increased with increasing C content because C is an austenite stabilizer element. The volume fractions of bainitic ferrite (BF) of the 0.15 wt% Si steels were higher than those of the 0.25 wt% Si steels, whereas the volume fractions of the secondary phases were lower. From the tensile properties before and after the aging process of the strainbased API X60 pipeline steels, the yield strength increased and the uniform and total elongation decreased, which is the strain aging effect. The strain aging effect in the strain-based API X60 pipeline steels was minimized when the volume fraction of AF was increased and secondary phases were distributed uniformly. On the other hand, an excessively high C content formed fine precipitates, and the strain aging effect occurred because of the interactions among dislocations and fine precipitates.

  1. [Resistance of Mycobacterium tuberculosis strains to antimycobacterial preparations].

    Science.gov (United States)

    Iavors'ka, H V; Puhachevs'ka, L P

    2006-01-01

    Investigations of dynamics of Mycobacterium tuberculosis strains, isolated from patients with pulmonary tuberculosis were carried out in the Lviv region during 1994-2003. As a result of conducted investigations the tendency was revealed to increasing the amount of cultures resistant to streptomycine, isoniazide, canamycine, ethambutol, ryfampycine and their multiresistance during the investigation years. High quantity of resistant strains was revealed in common in 1997, 1999 and 2002.

  2. In-situ strain localization analysis in low density transformation-twinning induced plasticity steel using digital image correlation

    Science.gov (United States)

    Eskandari, M.; Yadegari-Dehnavi, M. R.; Zarei-Hanzaki, A.; Mohtadi-Bonab, M. A.; Basu, R.; Szpunar, J. A.

    2015-04-01

    The effect of deformation temperature on the strain localization has been evaluated by an adapted digital image correlation (DIC) technique during tensile deformation. The progress of strain localization was traced by the corresponding strain maps. The electron backscatter diffraction analysis and tint etching technique were utilized to determine the impact of martensitic transformation and deformation twinning on the strain localization in both elastic and plastic regimes. In elastic regime the narrow strain bands which are aligned perpendicular to the tension direction were observed in temperature range of 25 to 180 °C due to the stress-assisted epsilon martensite. The strain bands were disappeared by increasing the temperature to 300 °C and reappeared at 400 °C due to the stress-assisted deformation twinning. In plastic regime strain localization continued at 25 °C and 180 °C due to the strain-induced alfa-martensite and deformation twinning, respectively. The intensity of plastic strain localization was increased by increasing the strain due to the enhancement of martensite and twin volume fraction. The plastic strain showed more homogeneity at 300 °C due to the lack of both strain-induced martensite and deformation twinning. Effect of deformation mechanism by changing temperature on strain localization is investigated by digital image correlation. EBSD technique is served to validate deformation mechanism as well as microstructural evolution. Strain induced martensite as well as deformation twinning is activated in the present steel affecting strain localization.

  3. Evaluation of local strain in Si using UV-Raman spectroscopy

    International Nuclear Information System (INIS)

    Ogura, Atsushi; Kosemura, Daisuke; Takei, Munehisa; Uchida, Hidetsugu; Hattori, Nobuyoshi; Yoshimaru, Masaki; Mayuzumi, Satoru; Wakabayashi, Hitoshi

    2009-01-01

    'Strained-Si', in which intentional strain is introduced in Si crystal to improve carrier mobility by using a modulated band structure, is recognized as one of the most important technologies in post-scaling-generation LSIs. Strain-evaluation technology to probe strain in shallow surfaces that correspond to the channels of MOSFETs is crucial to achieving strained-Si technology. In this paper, we introduce the results we obtained by evaluating strain with the new UV-Raman spectroscopy we developed. Quasi-line shape illumination enabled Raman measurements with 200-nm intervals on the sample. The local-strain mechanism caused by SiN stressors covering a MOSFET was clarified by measuring one-dimensional strain profiles induced by patterned SiN film on Si. We also demonstrated that the induced strain was proportional to the inner stresses of SiN film and that it is more effective to introduce strain in SOI substrates than in bulk substrates. In the evaluation of a actual device fabricated by using the gate-last process in which strain was significantly enhanced after the dummy gate was removed, the size effect, i.e., an increase in induced strain with a decrease in gate length, was confirmed through one-dimensional strain-profile measurements with various gate lengths.

  4. Enterobacter Strains Might Promote Colon Cancer.

    Science.gov (United States)

    Yurdakul, Dilşad; Yazgan-Karataş, Ayten; Şahin, Fikrettin

    2015-09-01

    Many studies have been performed to determine the interaction between bacterial species and cancer. However, there has been no attempts to demonstrate a possible relationship between Enterobacter spp. and colon cancer so far. Therefore, in the present study, it is aimed to investigate the effects of Enterobacter strains on colon cancer. Bacterial proteins were isolated from 11 Enterobacter spp., one Morganella morganii, and one Escherichia coli strains, and applied onto NCM460 (Incell) and CRL1790 (ATCC) cell lines. Cell viability and proliferation were determined in MTS assay. Flow Cytometry was used to detect CD24 level and apoptosis. Real-Time PCR studies were performed to determine NFKB and Bcl2 expression. Graphpad Software was used for statistical analysis. The results showed that proteins, isolated from the Enterobacter spp., have significantly increased cell viability and proliferation, while decreasing the apoptosis of the cell lines tested. The data in the present study indicated that Enterobacter strains might promote colon cancer. Moreover, Enterobacter spp. could be a clinically important factor for colon cancer initiation and progression. Studies can be extended on animal models in order to develop new strategies for treatment.

  5. Characterization of enterococcus strains contained in probiotic products.

    Science.gov (United States)

    Noguchi, Norihisa; Nakaminami, Hidemasa; Nakase, Keisuke; Sasatsu, Masanori

    2011-01-01

    Probiotics are additives containing live microbes that beneficially affect a host by improving the properties of the host intestinal microflora. Recently, advances in medical treatments have led to increased numbers of immunocompromised patients; some patients contract opportunistic infections of Enterococcus species, which are considered non-pathogenic bacteria. To evaluate the safety of probiotics containing Enterococcus strains, we isolated Enterococcus from six probiotic products and compared the pathogenic genes and antimicrobial susceptibility of the probiotic strains to those of clinical isolates. Our study showed that all Enterococcus strains contained in probiotic products were E. faecium, and no vancomycin-resistant strains were found. In addition, no pathogenic genes, such as ace, agg, gelE, cylM, cylB, cylA, cpd, cob, ccf, efaA(fs), efaA(fm), esp(fs), or esp(fm), were found in the probiotic strains. Pulsed-field gel electrophoresis (PFGE) analysis showed obvious genetic differences between the probiotic strains and the clinical isolates. The data suggested that the probiotic Enterococcus strains were not transmitted to hospitalized patients. Therefore, our results strongly suggest that probiotic products are unlikely agents for causing opportunistic infections.

  6. Strain fields and electronic structure of antiferromagnetic CrN

    Science.gov (United States)

    Rojas, Tomas; Ulloa, Sergio E.

    2017-09-01

    We present a theoretical analysis of the role that strain plays on the electronic structure of chromium nitride (CrN) crystals. We use local spin-density approximation + U calculations to study the elastic constants, deformation potentials, and strain dependence of electron and hole masses near the fundamental gap. We consider the lowest energy antiferromagnetic models believed to describe CrN at low temperatures, and apply strain along different directions. We find relatively large deformation potentials for all models, and find increasing gaps for tensile strain along most directions. Most interestingly, we find that compressive strains should be able to close the relatively small indirect gap (≃100 meV) at moderate amplitudes ≃1.3 % . We also find large and anisotropic changes in the effective masses with strain, with principal axes closely related to the magnetic ordering of neighboring layers in the antiferromagnet. It would be interesting to consider the role that these effects may have on typical film growth on different substrates, and the possibility of monitoring optical and transport properties of thin films as strain is applied.

  7. Strain effects on the work function of an organic semiconductor

    KAUST Repository

    Wu, Yanfei

    2016-02-01

    Establishing fundamental relationships between strain and work function (WF) in organic semiconductors is important not only for understanding electrical properties of organic thin films, which are subject to both intrinsic and extrinsic strains, but also for developing flexible electronic devices. Here we investigate tensile and compressive strain effects on the WF of rubrene single crystals. Mechanical strain induced by thermal expansion mismatch between the substrate and rubrene is quantified by X-ray diffraction. The corresponding WF change is measured by scanning Kelvin probe microscopy. The WF of rubrene increases (decreases) significantly with in-plane tensile (compressive) strain, which agrees qualitatively with density functional theory calculations. An elastic-to-plastic transition, characterized by a steep rise of the WF, occurs at ~0.05% tensile strain along the rubrene π-stacking direction. The results provide the first concrete link between mechanical strain and WF of an organic semiconductor and have important implications for understanding the connection between structural and electronic disorder in soft organic electronic materials.

  8. First-principles study of the transport behavior of zigzag graphene nanoribbons tailored by strain

    Directory of Open Access Journals (Sweden)

    Jinying Wang

    2012-03-01

    Full Text Available The charge transport properties of zigzag graphene nanoribbons (ZGNRs under uniaxial and shear strains are theoretically studied. Although all strained ZGNRs have similar metallic band structures, they show four types of transport behavior under bias voltages that depend on the type of strain and the mirror symmetry of the ZGNR. Under an applied uniaxial strain, the current of symmetric ZGNRs is consistently small, while for asymmetric ZGNRs it is large. In contrast, the current increases with increasing shear strain for symmetric ZGNRs while it decreases for asymmetric ZGNRs. The current properties merge when the shear strain exceeds a critical value, and the two systems then show similar behavior. Our results suggest that strained ZGNRs with an appropriate applied shear are ideal conducting wires.

  9. Hydrogen production by recombinant Escherichia coli strains

    Science.gov (United States)

    Maeda, Toshinari; Sanchez‐Torres, Viviana; Wood, Thomas K.

    2012-01-01

    Summary The production of hydrogen via microbial biotechnology is an active field of research. Given its ease of manipulation, the best‐studied bacterium Escherichia coli has become a workhorse for enhanced hydrogen production through metabolic engineering, heterologous gene expression, adaptive evolution, and protein engineering. Herein, the utility of E. coli strains to produce hydrogen, via native hydrogenases or heterologous ones, is reviewed. In addition, potential strategies for increasing hydrogen production are outlined and whole‐cell systems and cell‐free systems are compared. PMID:21895995

  10. Piezoresistive and piezoelectric MEMS strain sensors for vibration detection

    Science.gov (United States)

    Kon, Stanley; Oldham, Kenn; Horowitz, Roberto

    2007-04-01

    Both piezoresistive and piezoelectric materials are commonly used to detect strain caused by structural vibrations in macro-scale structures. With the increasing complexity and miniaturization of modern mechanical systems such as hard disk drive suspensions, it is imperative to explore the performance of these strain sensors when their dimensions must shrink along with those of the host structures. The miniaturized strain sensors must remain as small as possible so as to minimum their effect on structure dynamics, yet still have acceptable sensing resolution. The performances of two types of novel micro-scale strain gage for installation on stainless steel parts are compared in this paper. Micro-fabrication processes have been developed to build polycrystalline silicon piezoresistive strain sensors on a silicon substrate, which are later bonded to a steel substrate for testing. Piezoresistor geometries are optimized to effectively increase the gage factor of piezoresistive sensors while reducing sensor size. The advantage and disadvantage of these piezoresistors are compared to those of piezoelectric sensors. Experimental results reveal that the MEMS piezoelectric sensors are able to achieve a better resolution than piezoresistors, while piezoresistors can be built in much smaller areas. Both types of the MEMS strain sensors are capable of high sensitivity measurements, subject to differing constraints.

  11. Relationship between strain stored by compressive deformation and crystallographic orientation in a pure aluminum

    International Nuclear Information System (INIS)

    Takayama, Y; Watanabe, H; Yoshimura, T

    2015-01-01

    In order to investigate relationship between stored strain and crystallographic orientation, 99.99% purity aluminum cubes were compressed with uniaxial or with plane strain state up to a nominal strain of 30%. The aluminum cubes were examined on the same surface before and after compression by SEM/EBSD technique. Stored strain was estimated by Kernel Average Misorientation (KAM) derived from the EBSD analysis, and Taylor factor (TF) was measured before the compressive deformation. The analysis revealed that KAM value or the stored strain decreases until a certain value of TF and then increases with increment of TF. (paper)

  12. Enhanced hydrocarbon biodegradation by a newly isolated bacillus subtilis strain

    International Nuclear Information System (INIS)

    Christova, N.; Tuleva, B.; Nikolova-Damyanova, B.

    2004-01-01

    The relation between hydrocarbon degradation and biosurfactant (rhamnolipid) production by a new bacillus subtilis 22BN strain was investigated. The strain was isolated for its capacity to utilize n-hexadecane and naphthalene and at the same time to produce surface-active compound at high concentrations (1.5 - 2.0 g l -1 ). Biosurfactant production was detected by surface tension lowering and emulsifying activity. The strain is a good degrader of both hydrocarbons used with degradability of 98.3 ± 1% and 75 ± 2% for n-hexadecane and naphthalene, respectively. Measurement of cell hydrophobicity showed that the combination of slightly soluble substrate and rhamnolipid developed higher hydrophobicity correlated with increased utilization of both hydrocarbon substrates. To our knowledge, this is the first report of bacillus subtilis strain that degrades hydrophobic compounds and at the same time produces rhamnolipid biosurfactant. (orig.)

  13. Rehabilitation and return to sport after hamstring strain injury

    Directory of Open Access Journals (Sweden)

    Lauren N. Erickson

    2017-09-01

    Full Text Available Hamstring strain injuries are common among sports that involve sprinting, kicking, and high-speed skilled movements or extensive muscle lengthening-type maneuvers with hip flexion and knee extension. These injuries present the challenge of significant recovery time and a lengthy period of increased susceptibility for recurrent injury. Nearly one third of hamstring strains recur within the first year following return to sport with subsequent injuries often being more severe than the original. This high re-injury rate suggests that athletes may be returning to sport prematurely due to inadequate return to sport criteria. In this review article, we describe the epidemiology, risk factors, differential diagnosis, and prognosis of an acute hamstring strain. Based on the current available evidence, we then propose a clinical guide for the rehabilitation of acute hamstring strains and an algorithm to assist clinicians in the decision-making process when assessing readiness of an athlete to return to sport.

  14. ANALYSIS OF THE ACCURACY OF FIBRE-OPTIC STRAIN GAUGES

    Directory of Open Access Journals (Sweden)

    Dita Jiroutová

    2013-12-01

    Full Text Available In recent years, the field of structure monitoring has been making increasing use of systems based on fiber-optic technologies. Fiber-optic technology offers many advantages, including higher quality measurements, greater reliability, easier installation and maintenance, insensitivity to the environment (mainly to the electromagnetic field, corrosion resistance, safety in explosive and flammable environments, the possibility of long-term monitoring and lower cost per lifetime. We have used SOFO fibre-optic strain gauges to perform measurements to check the overall relative deformation of a real reinforced concrete structure. Long-term monitoring of the structure revealed that the measurement readings obtained from these fibre-optic strain gauges differed from each other. Greater attention was therefore paid to the calibration of the fibre-optic strain gauges, and to determining their measurement accuracy. The experimental results show that it is necessary to calibrate SOFO strain gauges before they are used, and to determine their calibration constant.

  15. Photoacoustic spectroscopy of Entamoeba histolytica strains

    Science.gov (United States)

    Acosta-Avalos, D.; Alvarado-Gil, J. J.; Silva, E. F.; Orozco, E.; de Menezes, L. F.; Vargas, H.

    2005-06-01

    Pathogenic and non-pathogenic strains of E. histolytica are studied using photoacoustic spectroscopy. It is shown that the pathogenic strain presents a spectrum similar to that of iron sulfur proteins. The non-pathogenic strain does not show any relevant absorption at the studied wavelength range. The differences observed between the optical absorption spectra of both strains opens the possibility of using photoacoustic spectroscopy as a reliable and simple technique to identify different types of E. histolytica strains.

  16. In silico comparison of bacterial strains using mutual information

    Indian Academy of Sciences (India)

    Fast-sequencing throughput methods have increased the number of completely sequenced bacterial genomes to about 400 by December 2006, with the number increasing rapidly. These include several strains. In silico methods of comparative genomics are of use in categorizing and phylogenetically sorting these bacteria ...

  17. Anterior Cruciate Ligament Strain In Vivo: A Systematic Review.

    Science.gov (United States)

    Luque-Seron, Juan Antonio; Medina-Porqueres, Ivan

    2016-09-01

    Distinct exercises have been proposed for knee rehabilitation after anterior cruciate ligament (ACL) reconstruction. There is a need to understand ACL strain behavior during different rehabilitation exercises to protect the graft from excessive strain that could interfere with its healing process. To critically review studies that directly measured normal ACL strain in vivo during different movements, conditions, or exercises to gain insight into which of them may produce more strain on the ligament or the ligament graft in the case of reconstructed knees. A literature search of PubMed, CINAHL, SPORTDiscus, and PEDro databases was conducted. Keywords included anterior cruciate ligament, strain, stress, deformation, transducer, rehabilitation, rehabilitation exercise, physical therapy, and physiotherapy. Inclusion criteria were (1) peer-reviewed studies published in English or Spanish, (2) research conducted on adult human subjects with normal ACLs and healthy knees, and (3) ACL strain directly measured during different movements, conditions, or exercises by using a transducer. Systematic review. Level 4. Specific data were abstracted from the selected studies, including isometric quadriceps and hamstrings activity, active and passive flexion-extension of the knee, closed kinetic chain exercises, and application of joint compressive load. A total of 10 studies met all criteria and were included in the final analysis. The strain values produced by closed kinetic chain and open kinetic chain exercises were similar. However, closed kinetic chain exercises appear to attenuate the strain increase that occurs in open kinetic chain exercises when increasing resistance. These data may be relevant to develop rehabilitation exercises or programs that do not endanger the healing ACL graft and to provide a basis for future clinical trials. © 2016 The Author(s).

  18. Strain gradient effects on cyclic plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Legarth, Brian Nyvang

    2010-01-01

    Size effects on the cyclic shear response are studied numerically using a recent higher order strain gradient visco-plasticity theory accounting for both dissipative and energetic gradient hardening. Numerical investigations of the response under cyclic pure shear and shear of a finite slab between...... rigid platens have been carried out, using the finite element method. It is shown for elastic–perfectly plastic solids how dissipative gradient effects lead to increased yield strength, whereas energetic gradient contributions lead to increased hardening as well as a Bauschinger effect. For linearly...... hardening materials it is quantified how dissipative and energetic gradient effects promote hardening above that of conventional predictions. Usually, increased hardening is attributed to energetic gradient effects, but here it is found that also dissipative gradient effects lead to additional hardening...

  19. Analysis of local deformation effects in resistive strain sensing of a submicron-thickness AFM cantilever

    Science.gov (United States)

    Adams, Jonathan D.; Schwalb, Christian H.; Winhold, Marcel; Šńukić, Maja; Huth, Michael; Fantner, Georg E.

    2013-05-01

    Incorporating resistive strain-sensing elements into MEMS devices is a long-standing approach for electronic detection of the device deformation. As the need for more sensitivity trends the device dimensions downwards, the size of the strain-sensor may become comparable to the device size, which can have significant impact on the mechanical behaviour of the device. To study this effect, we modelled a submicron-thickness silicon nitride AFM cantilever with strain-sensing element. Using finite element analysis, we calculated the strain in the sensor elements for a deflected cantilever. The sensor element contributes to a local stiffening effect in the device structure which lowers the strain in the sensor. By varying the sensor geometry, we investigated the degree to which this effect impacts the strain. Minimizing the sensor size increases the strain, but the reduction in sensor cross-sectional area increases the resistance and expected sensor noise. The optimal sensor geometry must therefore account for this effect. We used our analysis to optimize geometric variations of nanogranular tunnelling resistor (NTR) strain sensors arranged in a Wheatstone bridge on a silicon nitride AFM cantilever. We varied the dimensions of each sensor element to maintain a constant cross-sectional area but maximize the strain in the sensor element. Through this approach, we expect a 45% increase in strain in the sensor and corresponding 20% increase in the Wheatstone bridge signal. Our results provide an important consideration in the design geometry of resistive strainsensing elements in MEMS devices.

  20. The Effect of Grain Size on the Strain Hardening Behavior for Extruded ZK61 Magnesium Alloy

    Science.gov (United States)

    Zhang, Lixin; Zhang, Wencong; Chen, Wenzhen; Duan, Junpeng; Wang, Wenke; Wang, Erde

    2017-12-01

    The effects of grain size on the tensile and compressive strain hardening behaviors for extruded ZK61 alloys have been investigated by uniaxial tensile and compressive tests along the extrusion directions. Cylindrical tension and compression specimens of extruded ZK61 alloys with various sized grain were fabricated by annealing treatments. Tensile and compressive tests at ambient temperature were conducted at a strain rate of 0.5 × 10-3 s-1. The results indicate that both tensile strain hardening and compressive strain hardening of ZK61 alloys with different grain sizes have an athermal regime of dislocation accumulation in early deformation. The threshold stress value caused dynamic recovery is predominantly related to grain size in tensile strain hardening, but the threshold stress values for different grain sizes are almost identical in compressive strain hardening. There are obvious transition points on the tensile strain hardening curves which indicate the occurrence of dynamic recrystallization (DRX). The tensile strain hardening rate of the coarse-grained alloy obviously decreases faster than that of fine-grained alloys before DRX and the tensile strain hardening curves of different grain sizes basically tend to parallel after DRX. The compressive strain hardening rate of the fine-grained alloy obviously increases faster than that of coarse-grained alloy for twin-induced strain hardening, but compressive strain hardening curves also tend to parallel after twinning is exhausted.

  1. Influence of mechanical strain on magnetic characteristics of spin valves

    Science.gov (United States)

    Áč, V.; Anwarzai, B.; Luby, S.; Majkova, E.

    2008-03-01

    Giant magnetoresistance (GMR) of Co and Fe-Co based e-beam evaporated spin valves with Cu and Au spacers was studied. The effect of strain on samples, which is detrimental in standard GMR sensors, was measured in a bending configuration. The different dependences of coercivity Hc and magnetic field Hip in the point of inflection of MR loops vs. strain were found. For sample with Co/Au/Co core, Hc, Hip increase with increasing compressive stress, whereas for sample with FeCo/Cu/Co core they increase with tensile stress. The highest relative change of MR ratio vs. bending in the strain interval ± 300 × 10-6 is 1-2 % of the basic magnetoresistance and, practically, it does not influence the SV output.

  2. Influence of mechanical strain on magnetic characteristics of spin valves

    International Nuclear Information System (INIS)

    Ac, V; Anwarzai, B; Luby, S; Majkova, E

    2008-01-01

    Giant magnetoresistance (GMR) of Co and Fe-Co based e-beam evaporated spin valves with Cu and Au spacers was studied. The effect of strain on samples, which is detrimental in standard GMR sensors, was measured in a bending configuration. The different dependences of coercivity H c and magnetic field H ip in the point of inflection of MR loops vs. strain were found. For sample with Co/Au/Co core, H c , H ip increase with increasing compressive stress, whereas for sample with FeCo/Cu/Co core they increase with tensile stress. The highest relative change of MR ratio vs. bending in the strain interval ± 300 x 10 -6 is 1-2 % of the basic magnetoresistance and, practically, it does not influence the SV output

  3. Mobilomics in Saccharomyces cerevisiae strains.

    Science.gov (United States)

    Menconi, Giulia; Battaglia, Giovanni; Grossi, Roberto; Pisanti, Nadia; Marangoni, Roberto

    2013-03-20

    Mobile Genetic Elements (MGEs) are selfish DNA integrated in the genomes. Their detection is mainly based on consensus-like searches by scanning the investigated genome against the sequence of an already identified MGE. Mobilomics aims at discovering all the MGEs in a genome and understanding their dynamic behavior: The data for this kind of investigation can be provided by comparative genomics of closely related organisms. The amount of data thus involved requires a strong computational effort, which should be alleviated. Our approach proposes to exploit the high similarity among homologous chromosomes of different strains of the same species, following a progressive comparative genomics philosophy. We introduce a software tool based on our new fast algorithm, called regender, which is able to identify the conserved regions between chromosomes. Our case study is represented by a unique recently available dataset of 39 different strains of S.cerevisiae, which regender is able to compare in few minutes. By exploring the non-conserved regions, where MGEs are mainly retrotransposons called Tys, and marking the candidate Tys based on their length, we are able to locate a priori and automatically all the already known Tys and map all the putative Tys in all the strains. The remaining putative mobile elements (PMEs) emerging from this intra-specific comparison are sharp markers of inter-specific evolution: indeed, many events of non-conservation among different yeast strains correspond to PMEs. A clustering based on the presence/absence of the candidate Tys in the strains suggests an evolutionary interconnection that is very similar to classic phylogenetic trees based on SNPs analysis, even though it is computed without using phylogenetic information. The case study indicates that the proposed methodology brings two major advantages: (a) it does not require any template sequence for the wanted MGEs and (b) it can be applied to infer MGEs also for low coverage genomes

  4. Comparative genomic characterization of citrus-associated Xylella fastidiosa strains

    Directory of Open Access Journals (Sweden)

    Nunes Luiz R

    2007-12-01

    identified ORFs, obtained by SSH, represent an approximately 10% increase in our current knowledge of the South American Xf gene pool and include new putative virulence factors, as well as novel potential markers for strain identification. Surprisingly, this list of novel elements include sequences previously believed to be unique to North American strains, pointing to the necessity of revising the list of specific markers that may be used for identification of distinct Xf strains.

  5. Inverse strain rate effect on cyclic stress response in annealed Zircaloy-2

    Energy Technology Data Exchange (ETDEWEB)

    Sudhakar Rao, G.; Verma, Preeti [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Chakravartty, J.K. [Mechanical Metallurgy Group, Bhabha Atomic Research Center, Trombay 400 085, Mumbai (India); Nudurupati, Saibaba [Nuclear Fuel Complex, Hyderabad 500 062 (India); Mahobia, G.S.; Santhi Srinivas, N.C. [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Singh, Vakil, E-mail: vsingh.met@itbhu.ac.in [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2015-02-15

    Low cycle fatigue behavior of annealed Zircaloy-2 was investigated at 300 and 400 °C at different strain amplitudes and strain rates of 10{sup −2}, 10{sup −3}, and 10{sup −4} s{sup −1}. Cyclic stress response showed initial hardening with decreasing rate of hardening, followed by linear cyclic hardening and finally secondary hardening with increasing rate of hardening for low strain amplitudes at both the temperatures. The rate as well the degree of linear hardening and secondary hardening decreased with decrease in strain rate at 300 °C, however, there was inverse effect of strain rate on cyclic stress response at 400 °C and cyclic stress was increased with decrease in strain rate. The fatigue life decreased with decrease in strain rate at both the temperatures. The occurrence of linear cyclic hardening, inverse effect of strain rate on cyclic stress response and deterioration in fatigue life with decrease in strain rate may be attributed to dynamic strain aging phenomena resulting from enhanced interaction of dislocations with solutes. Fracture surfaces revealed distinct striations, secondary cracking, and oxidation with decrease in strain rate. Deformation substructure showed parallel dislocation lines and dislocation band structure at 300 °C. Persistent slip band wall structure and development of fine Corduroy structure was observed at 400 °C.

  6. Engineering and preclinical evaluation of attenuated nontyphoidal Salmonella strains serving as live oral vaccines and as reagent strains.

    Science.gov (United States)

    Tennant, Sharon M; Wang, Jin-Yuan; Galen, James E; Simon, Raphael; Pasetti, Marcela F; Gat, Orit; Levine, Myron M

    2011-10-01

    While nontyphoidal Salmonella (NTS) has long been recognized as a cause of self-limited gastroenteritis, it is becoming increasingly evident that multiple-antibiotic-resistant strains are also emerging as important causes of invasive bacteremia and focal infections, resulting in hospitalizations and deaths. We have constructed attenuated Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis strains that can serve as live oral vaccines and as "reagent strains" for subunit vaccine production in a safe and economical manner. Prototype attenuated vaccine strains CVD 1921 and CVD 1941, derived from the invasive wild-type strains S. Typhimurium I77 and S. Enteritidis R11, respectively, were constructed by deleting guaBA, encoding guanine biosynthesis, and clpP, encoding a master protease regulator. The clpP mutation resulted in a hyperflagellation phenotype. An additional deletion in fliD yielded reagent strains CVD 1923 and CVD 1943, respectively, which export flagellin monomers. Oral 50% lethal dose (LD₅₀) analyses showed that the NTS vaccine strains were all highly attenuated in mice. Oral immunization with CVD 1921 or CVD 1923 protected mice against lethal challenge with wild-type S. Typhimurium I77. Immunization with CVD 1941 but not CVD 1943 protected mice against lethal infection with S. Enteritidis R11. Immune responses induced by these strains included high levels of serum IgG anti-lipopolysaccharide (LPS) and anti-flagellum antibodies, with titers increasing progressively during the immunization schedule. Since S. Typhimurium and S. Enteritidis are the most common NTS serovars associated with invasive disease, these findings can pave the way for development of a highly effective, broad-spectrum vaccine against invasive NTS.

  7. Effect of in site strain on passivated property of the 316L stainless steels.

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Ting, Guo

    2016-04-01

    The effect of the strain of 316L stainless steel on its corrosion resistance in borate buffer solution was investigated by in site tensile test and the electrochemical impedance spectroscopy measurements. It was found that the corrosion resistance of the 316L stainless steel decreased with the increasing of in site strain. The lower corrosion resistance of the stainless steel during in site strain was mainly attributed to the higher doping concentration in passive film. Especially, with the increasing of in site strain, the concentrations of acceptor (i.e., cation vacancies) in the passive films significantly increased. More acceptor concentrations reduced the compactness of the passive film and its corrosion resistance. Moreover, two exponential relationships were found between in site strain and the charge transfer resistance of the passive film and between in site strain and total doping concentrations in passive film, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. GC-MS-Based Metabonomic Profiling Displayed Differing Effects of Borna Disease Virus Natural Strain Hu-H1 and Laboratory Strain V Infection in Rat Cortical Neurons.

    Science.gov (United States)

    Liu, Siwen; Bode, Liv; Zhang, Lujun; He, Peng; Huang, Rongzhong; Sun, Lin; Chen, Shigang; Zhang, Hong; Guo, Yujie; Zhou, Jingjing; Fu, Yuying; Zhu, Dan; Xie, Peng

    2015-08-17

    Borna disease virus (BDV) persists in the central nervous systems of a wide variety of vertebrates and causes behavioral disorders. Previous studies have revealed that metabolic perturbations are associated with BDV infection. However, the pathophysiological effects of different viral strains remain largely unknown. Rat cortical neurons infected with human strain BDV Hu-H1, laboratory BDV Strain V, and non-infected control (CON) cells were cultured in vitro. At day 12 post-infection, a gas chromatography coupled with mass spectrometry (GC-MS) metabonomic approach was used to differentiate the metabonomic profiles of 35 independent intracellular samples from Hu-H1-infected cells (n = 12), Strain V-infected cells (n = 12), and CON cells (n = 11). Partial least squares discriminant analysis (PLS-DA) was performed to demonstrate discrimination between the three groups. Further statistical testing determined which individual metabolites displayed significant differences between groups. PLS-DA demonstrated that the whole metabolic pattern enabled statistical discrimination between groups. We identified 31 differential metabolites in the Hu-H1 and CON groups (21 decreased and 10 increased in Hu-H1 relative to CON), 35 differential metabolites in the Strain V and CON groups (30 decreased and 5 increased in Strain V relative to CON), and 21 differential metabolites in the Hu-H1 and Strain V groups (8 decreased and 13 increased in Hu-H1 relative to Strain V). Comparative metabonomic profiling revealed divergent perturbations in key energy and amino acid metabolites between natural strain Hu-H1 and laboratory Strain V of BDV. The two BDV strains differentially alter metabolic pathways of rat cortical neurons in vitro. Their systematic classification provides a valuable template for improved BDV strain definition in future studies.

  9. The effects of academic and interpersonal stress on dating violence among college students: a test of classical strain theory.

    Science.gov (United States)

    Mason, Brandon; Smithey, Martha

    2012-03-01

    This study examines Merton's Classical Strain Theory (1938) as a causative factor in intimate partner violence among college students. We theorize that college students experience general life strain and cumulative strain as they pursue the goal of a college degree. We test this strain on the likelihood of using intimate partner violence. Strain due to unrealistic expectations of intimate partnership and economic strain are also examined. The analysis examines the following causative factors representing strain: 1) the College Undergraduate Stress Scale (Renner & Mackin, 1998); 2) cumulative academic strain measured by college classification; 3) cumulative intimate partner strain measured as the length of time in the relationship; 4) academic strain measured by number of hours studied weekly, and 5) economic strain measured by number of hours worked weekly. Additionally, we examine the extent to which gender and race/ethnicity differentially affect intimate partner in the context of these measures of strain. The Conflict Tactics Scales II (Straus et al, 1996) are used to measure dating violence and include indicators for sexual coercion, physical aggression, injury, and psychological aggression. Data were collected from 142 students in lower-division classes from Texas Tech University. Results show that general strain and cumulative intimate partner strain increase the use of dating violence among college students. The longer dating partners are in a relationship, the higher the chances of psychological aggression, physical assault, and sexual coercion. Converse to our expectations, time spent working reduces psychological aggression due to reducing time spent together rather than reflecting economic strain.

  10. Human Achilles tendon plasticity in response to cyclic strain: effect of rate and duration.

    Science.gov (United States)

    Bohm, Sebastian; Mersmann, Falk; Tettke, Martin; Kraft, Marc; Arampatzis, Adamantios

    2014-11-15

    High strain magnitude and low strain frequency are important stimuli for tendon adaptation. Increasing the rate and duration of the applied strain may enhance the adaptive responses. Therefore, our purpose was to investigate the effect of strain rate and duration on Achilles tendon adaptation. The study included two experimental groups (N=14 and N=12) and a control group (N=13). The participants of the experimental groups exercised according to a reference protocol (14 weeks, four times a week), featuring a high strain magnitude (~6.5%) and a low strain frequency (0.17 Hz, 3 s loading/3 s relaxation) on one leg and with either a higher strain rate (one-legged jumps) or a longer strain duration (12 s loading) on the other leg. The strain magnitude and loading volume were similar in all protocols. Before and after the interventions, the tendon stiffness, Young's modulus and cross-sectional area were examined using magnetic resonance imaging, ultrasound and dynamometry. The reference and long strain duration protocols induced significantly increased (P<0.05) tendon stiffness (57% and 25%), cross-sectional area (4.2% and 5.3%) and Young's modulus (51% and 17%). The increases in tendon stiffness and Young's modulus were higher in the reference protocol. Although region-specific tendon hypertrophy was also detected after the high strain rate training, there was only a tendency of increased stiffness (P=0.08) and cross-sectional area (P=0.09). The control group did not show any changes (P=0.86). The results provide evidence that a high strain magnitude, an appropriate strain duration and repetitive loading are essential components for an efficient adaptive stimulus for tendons. © 2014. Published by The Company of Biologists Ltd.

  11. Effect of Mycobacterium sp. strain CH1 and mycobacterium sp. strain CH2 on the degradation of four-ring creosote compounds.

    Science.gov (United States)

    Harper, Jennifer Paige; Churchill, Perry F; Lokey-Flippo, Laura; Lalor, Melinda M

    2005-01-01

    The influence of nutrients, Mycobacterium sp. strain CH1 and Mycobacterium sp. strain CH2 on the degradation of aged creosote hydrocarbon contaminants was investigated. The Mycobacterium sp. strain CH2 showed the highest positive influence on the degradation of three- and four-ring PAH compounds. The addition of Mycobacterium sp. strain CH1 had the second highest measured positive influence on the degradation of four-ring compounds. Soluble nitrogen and phosphorus also increased the degradation of aged creosote compounds in the contaminated soil. The addition of bacteria decreased the number of measured bacterial species, indicating competition for limited nutrients in the soil.

  12. Influence of strain on band structure of semiconductor nanostructures

    Directory of Open Access Journals (Sweden)

    Raičević Nevena

    2009-01-01

    Full Text Available The influence of the mechanical strain on the electronic structure of the asymmetric (In,GaAs/GaAs quantum well is considered. Both the direct influence of strain on the orbital part of the electronic structure and an indirect influence through the strain dependent Rashba and Dresselhaus Hamiltonians are taken into account. The analyzed quantum well is taken to have a triangular shape, and is oriented along the direction. For this direction, there exists both the intrinsic and strain-induced spin-orbit interaction. For all analyzed types of spin-orbit interaction, subband splittings depend linearly on the in-plane wave vector. On the other hand, the electronic structure for the Rashba type of the strain-induced spin-orbit interaction shows isotropic dependence in the k-space, while the electronic structure due to the Dresselhaus type shows anisotropy. Furthermore, the Rashba strain-induced spin-orbit interaction increases subband splitting, while the effect of the Dresselhaus Hamiltonian on the electronic structure is opposite to the intrinsic spin-orbit interaction for certain polar angles.

  13. Construction of l-Isoleucine Overproducing Strains of Corynebacterium glutamicum

    Science.gov (United States)

    Sahm, H.; Eggeling, L.; Morbach, S.; Eikmanns, B.

    Nowadays the gram-positive bacterium Corynebacterium glutamicum is used for the industrial production of the amino acids l-glutamate (1×106tons/year) and l-lysine (300×103tons/year). The classical approach to obtain amino acid overproducing strains of C. glutamicum was mutagenesis and then a selection of mutants. In the past 10 years the genetic engineering and amplification of genes have become fascinating methods for studying metabolic pathways in greater detail and for constructing microbial strains with desired genotypes. To obtain l-isoleucine overproducing strains of C. glutamicum we therefore studied the l-isoleucine biosynthesis by overexpression of the various corresponding genes. To enable a flux increase in recombinant strains all genes specific for l-threonine and l-isoleucine biosynthesis were cloned from this bacterium. We demonstratet that amplification of the feedback inhibition insensitive homoserine dehydrogenase and homoserine kinase in a high l-lysine overproducing strain enable the channeling of the carbon flow from the intermediate l-aspartate semialdehyde towards homoserine, resulting in an accumulation of l-threonine. To obtain effective l-isoleucine overproduction a deregulated threonine dehydratase was overexpressed in l-threonine producing strains of C. glutamicum. In this way the l-threonine was converted to l-isoleucine, which was secreted up to 30g/l into the culture medium.

  14. Immunosuppression with cyclophosphamide favors reinfection with recombinant Toxoplasma gondii strains

    Directory of Open Access Journals (Sweden)

    Silva L.A.

    2012-08-01

    Full Text Available The aim of this study was to verify the effect of immunosuppression by cyclophosphamide (Cy on susceptibility of BALB/c mice subjected to challenge with recombinant strains of Toxoplasma gondii. Animals were prime infected with the D8 (recombinant I/III or the ME49 (type II non-virulent strains, weekly immunosuppressed with Cy and challenged with the CH3 or EGS virulent strains (I/III. Parasites recovered from surviving mice were submitted to PCR-RFLP analysis to confirm co-infection. Prime-infection with the D8 strain conferred more protection against challenge with the CH3 and EGS strains when compared with ME49 prime infection. Cy treatment caused significant leukopenia in the infected mice, what probably favors reinfection after challenge. Reinfection was associated with increased levels of IgA. Otherwise, Cy-treated mice presented significantly lower IgA levels after challenge, suggesting involvement of this immunoglobulin on protection against reinfection. In conclusion, BALB/c mice susceptibility to reinfection by T. gondii is related to genetic differences among the strains used for primary and challenge infections. Alteration of the host’s immune integrity by Cy probably compromises the protection previously established by primary infection.

  15. Endosulfan degradation by a Rhodococcus strain isolated from earthworm gut.

    Science.gov (United States)

    Verma, K; Agrawal, N; Farooq, M; Misra, R B; Hans, R K

    2006-07-01

    A Rhodococcus MTCC 6716 bacterial strain was isolated apparently for the first time from the gut microflora of an Indian earthworm (Metaphire posthuma). Endosulfan was used as a carbon source by the strain and degraded it up to 92.58% within 15 days. Furthermore, the isolated strain of the bacterium did not produce the persistent form of the toxic metabolite endosulfan sulfate. This strain exhibits luxury growth in minimal medium with high concentrations of endosulfan (80 microg mL(-1)). Degradation of the endosulfan occurred simultaneously with bacterial growth and an increase in chloride ion (87.1%) in the growth medium, suggesting nearly complete degradation of the insecticide. This strain is able to tolerate 45 degrees C and retain its degradation potential even under sunlight exposure. Since endosulfan is used worldwide for pest control and its residues have been retained for long periods in soil, water, and agricultural products, the strain isolated by us is valuable for bioremediation of endosulfan-contaminated soil and water.

  16. Strain stiffening and stress heterogeneities in sheared collagen networks

    Science.gov (United States)

    Urbach, Jeffrey

    2014-03-01

    Disordered networks of stiff or semi-flexible filaments display unusual mechanical properties, including dramatic stiffening when sheared, but little is known about the spatial distribution of stresses. This talk will introduce the technique of Boundary Stress Microscopy, which adapts the approach of traction force microscopy to rheological measurements in order to quantify the non-uniform surface stresses in sheared soft materials. Our results on networks of the biopolymer collagen, a major component of the extracellular matrix, show stress variations over length scales much larger than the network mesh size. We find that the heterogeneity increases with strain stiffening, with stresses at high strains exceeding average stresses by an order of magnitude. The strain stiffening behavior over a wide range of mesh sizes can be parameterized by a single characteristic strain and associated stress, which describes both the strain stiffening regime and network yielding. The characteristic stress is approximately proportional to network density, but the peak stress at both the characteristic strain and at yielding are remarkably insensitive to concentration. These results show the power of Boundary Stress Microscopy to reveal the nature of stress propagation in disordered soft materials, which is critical for understanding many important mechanical properties, including the ultimate strength of a material and the nature of appropriate microscopic constitutive equations. Supported by the AFOSR (FA9550-10-1-0473) and the NSF (DMR-0804782).

  17. Elevated temperature stress strain behavior of beryllium powder product

    Energy Technology Data Exchange (ETDEWEB)

    Abeln, S.P.; Field, R. [Los Alamos National Lab., NM (United States); Mataya, M.C. [Safe Sites of Colorado, Golden, CO (United States)

    1995-09-01

    Several grades of beryllium powder product were tested under isothermal conditions in compression over a temperature range of room temperature to 1000 C and a strain rate range from 0.001 s{sup {minus}1} to 1 s{sup {minus}1}. Samples were compressed to a total strain of 1 (64% reduction in height). It is shown that all the grades are strain rate sensitive and that strain rate sensitivity increases with temperature. Yield points were exhibited by some grades up to a temperature of 500 C, and appeared to be primarily dependent on prior thermal history which determined the availability of mobile dislocations. Serrated flow in the form of stress drops was seen in all the materials tested and was most pronounced at 500 C. The appearance and magnitude of the stress drops were dependent on accumulated strain, strain rate, sample orientation, and composition. The flow stress and shape of the flow curves differed significantly from grade to grade due to variations in alloy content, the size and distribution of BeO particles, aging precipitates, and grain size. The ductile-brittle transition temperature (DBTT) was determined for each grade of material and shown to be dependent on composition and thermal treatment. Structure/property relationships are discussed using processing history, microscopy (light and transmission), and property data.

  18. Diversity of Streptococcus mutans strains in bacterial interspecies interactions.

    Science.gov (United States)

    Li, Xiaolan; Hoogenkamp, Michel A; Ling, Junqi; Crielaard, Wim; Deng, Dong Mei

    2014-02-01

    Biofilms are matrix-enclosed microbial population adhere to each other and to surfaces. Compared to planktonic bacterial cells, biofilm cells show much higher levels of antimicrobial resistance. We aimed to investigate Streptococcus mutans strain diversity in biofilm formation and chlorhexidine (CHX) resistance of single S. mutans and dual S. mutans-Enterococcus faecalis biofilms. Four clinical S. mutans strains (C180-2, C67-1, HG723 and UA159) formed 24-h biofilms with or without an E. faecalis strain. These biofilms were treated for 10 min with 0.025% CHX. Biofilm formation, CHX resistance and S.mutans-E. faecalis interactions were evaluated by biomass staining, resazurin metabolism, viable count and competition agar assays. The main finding is that the presence of E. faecalis generally reduced all dual-species biofilm formation, but the proportions of S. mutans in the dual-species biofilms as well as CHX resistance displayed a clear S. mutans strain dependence. In particular, decreased resistance against CHX was observed in dual S. mutans C67-1 biofilms, while increased resistance was found in dual S. mutans UA159 biofilms. In conclusion, the interaction of S. mutans with E. faecalis in biofilms varies between strains, which underlines the importance of studying strain diversity in inter-species virulence modulation and biofilm antimicrobial resistance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Elevated temperature stress strain behavior of beryllium powder product

    International Nuclear Information System (INIS)

    Abeln, S.P.; Field, R.; Mataya, M.C.

    1995-01-01

    Several grades of beryllium powder product were tested under isothermal conditions in compression over a temperature range of room temperature to 1000 C and a strain rate range from 0.001 s -1 to 1 s -1 . Samples were compressed to a total strain of 1 (64% reduction in height). It is shown that all the grades are strain rate sensitive and that strain rate sensitivity increases with temperature. Yield points were exhibited by some grades up to a temperature of 500 C, and appeared to be primarily dependent on prior thermal history which determined the availability of mobile dislocations. Serrated flow in the form of stress drops was seen in all the materials tested and was most pronounced at 500 C. The appearance and magnitude of the stress drops were dependent on accumulated strain, strain rate, sample orientation, and composition. The flow stress and shape of the flow curves differed significantly from grade to grade due to variations in alloy content, the size and distribution of BeO particles, aging precipitates, and grain size. The ductile-brittle transition temperature (DBTT) was determined for each grade of material and shown to be dependent on composition and thermal treatment. Structure/property relationships are discussed using processing history, microscopy (light and transmission), and property data

  20. Tuning magnetism by biaxial strain in native ZnO.

    Science.gov (United States)

    Peng, Chengxiao; Wang, Yuanxu; Cheng, Zhenxiang; Zhang, Guangbiao; Wang, Chao; Yang, Gui

    2015-07-07

    Magnetic ZnO, one of the most important diluted magnetic semiconductors (DMS), has attracted great scientific interest because of its possible technological applications in optomagnetic devices. Magnetism in this material is usually delicately tuned by the doping level, dislocations, and local structures. The rational control of magnetism in ZnO is a highly attractive approach for practical applications. Here, the tuning effect of biaxial strain on the d(0) magnetism of native imperfect ZnO is demonstrated through first-principles calculations. Our calculation results show that strain conditions have little effect on the defect formation energy of Zn and O vacancies in ZnO, but they do affect the magnetism significantly. For a cation vacancy, increasing the compressive strain will obviously decrease its magnetic moment, while tensile strain cannot change the moment, which remains constant at 2 μB. For a singly charged anion vacancy, however, the dependence of the magnetic moment on strain is opposite to that of the Zn vacancy. Furthermore, the ferromagnetic state is always present, irrespective of the strain type, for ZnO with two zinc vacancies, 2VZns. A large tensile strain is favorable for improving the Curie temperature and realizing room temperature ferromagnetism for ZnO-based native semiconductors. For ZnO with two singly charged oxygen vacancies, 2Vs, no ferromagnetic ordering can be observed. Our work points the way to the rational design of materials beyond ZnO with novel non-intrinsic functionality by simply tuning the strain in a thin film form.

  1. Beryllium strain under dynamic loading

    Directory of Open Access Journals (Sweden)

    Pushkov Victor

    2015-01-01

    Full Text Available There are some data (not much on dynamic characteristics of beryllium that are important, for example, when estimating construction performance at NPP emergencies. A number of data on stress-strain curves, spall strength, shear strength, fracture and structure responses of shock loaded beryllium have obtained in US and Russian laboratories. For today the model description of this complex metal behavior does not have a reasonable agreement with the experimental data, thus a wider spectrum of experimental data is required. This work presents data on dynamic compression-test diagrams of Russian beryllium. Experiments are performed using Hopkinson bar method (SHPB. Strain rates were ε ∼ 103 s−1.

  2. Design and Validation of a Cyclic Strain Bioreactor to Condition Spatially-Selective Scaffolds in Dual Strain Regimes

    Directory of Open Access Journals (Sweden)

    J. Matthew Goodhart

    2014-03-01

    Full Text Available The objective of this study was to design and validate a unique bioreactor design for applying spatially selective, linear, cyclic strain to degradable and non-degradable polymeric fabric scaffolds. This system uses a novel three-clamp design to apply cyclic strain via a computer controlled linear actuator to a specified zone of a scaffold while isolating the remainder of the scaffold from strain. Image analysis of polyethylene terephthalate (PET woven scaffolds subjected to a 3% mechanical stretch demonstrated that the stretched portion of the scaffold experienced 2.97% ± 0.13% strain (mean ± standard deviation while the unstretched portion experienced 0.02% ± 0.18% strain. NIH-3T3 fibroblast cells were cultured on the PET scaffolds and half of each scaffold was stretched 5% at 0.5 Hz for one hour per day for 14 days in the bioreactor. Cells were checked for viability and proliferation at the end of the 14 day period and levels of glycosaminoglycan (GAG and collagen (hydroxyproline were measured as indicators of extracellular matrix production. Scaffolds in the bioreactor showed a seven-fold increase in cell number over scaffolds cultured statically in tissue culture plastic petri dishes (control. Bioreactor scaffolds showed a lower concentration of GAG deposition per cell as compared to the control scaffolds largely due to the great increase in cell number. A 75% increase in hydroxyproline concentration per cell was seen in the bioreactor stretched scaffolds as compared to the control scaffolds. Surprisingly, little differences were experienced between the stretched and unstretched portions of the scaffolds for this study. This was largely attributed to the conditioned and shared media effect. Results indicate that the bioreactor system is capable of applying spatially-selective, linear, cyclic strain to cells growing on polymeric fabric scaffolds and evaluating the cellular and matrix responses to the applied strains.

  3. Nepenthesin protease activity indicates digestive fluid dynamics in carnivorous Nepenthes plants

    NARCIS (Netherlands)

    Buch, F. (Franziska); W.E. Kaman (Wendy); F.J. Bikker (Floris); Yilamujiang, A. (Ayufu); Mithöfer, A. (Axel)

    2015-01-01

    textabstractCarnivorous plants use different morphological features to attract, trap and digest prey, mainly insects. Plants from the genus Nepenthes possess specialized leaves called pitchers that function as pitfall-traps. These pitchers are filled with a digestive fluid that is generated by the

  4. Nepenthesin protease activity indicates digestive fluid dynamics in carnivorous Nepenthes plants

    NARCIS (Netherlands)

    Buch, F.; Kaman, W.E.; Bikker, F.J.; Yilamujiang, A.; Mithöfer, A.

    2015-01-01

    Carnivorous plants use different morphological features to attract, trap and digest prey, mainly insects. Plants from the genus Nepenthes possess specialized leaves called pitchers that function as pitfall-traps. These pitchers are filled with a digestive fluid that is generated by the plants

  5. Conservative Mechanisms of Extracellular Trap Formation by Annelida Eisenia andrei: Serine Protease Activity Requirement.

    Directory of Open Access Journals (Sweden)

    Joanna Homa

    Full Text Available Formation of extracellular traps (ETs capturing and immobilizing pathogens is now a well-established defense mechanism added to the repertoire of vertebrate phagocytes. These ETs are composed of extracellular DNA (extDNA, histones and antimicrobial proteins. Formation of mouse and human ETs depends on enzymes (i facilitating decondensation of chromatin by citrullination of histones, and (ii serine proteases degrading histones. In invertebrates, initial reports revealed existence of ETs composed of extDNA and histones, and here we document for the first time that also coelomocytes, immunocompetent cells of an earthworm Eisenia andrei, cast ETs which successfully trap bacteria in a reactive oxygen species (ROS-dependent and -independent manner. Importantly, the formation of ETs was observed not only when coelomocytes were studied ex vivo, but also in vivo, directly in the earthworm coelom. These ETs were composed of extDNA, heat shock proteins (HSP27 and H3 histones. Furthermore, the formation of E. andrei ETs depended on activity of serine proteases, including elastase-like activity. Moreover, ETs interconnected and hold together aggregating coelomocytes, a processes proceeding encapsulation. In conclusion, the study confirms ET formation by earthworms, and unravels mechanisms leading to ET formation and encapsulation in invertebrates.

  6. Anti-HIV-1 protease activities of crude extracts of some Garcinia ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-22

    Mar 22, 2010 ... indicated significant HIV-1 protease inhibition (Chen et al., 1996). Garcinia livingstoneii has been reported to produce gutifferone A, being an anti-HIV ..... Abe F, Estrada MJ, Soler C, Chilpa RR. (2004). HIV-1 inhibitory compounds from Calophyllum brasiliense leaves. Biol. Pharm. Bull. 27: 1471-1475.

  7. Basis Tetrapeptides as Potent Intracellular Inhibitors of type A Botulinum Neurotoxin Protease Activity

    Energy Technology Data Exchange (ETDEWEB)

    Hale, M.; Swaminathan, S.; Oyler, G.; Ahmed, S. A.

    2011-01-21

    Botulinum neurotoxins (BoNT) are the most potent of all toxins that cause flaccid muscle paralysis leading to death. They are also potential biothreat agents. A systematic investigation of various short peptide inhibitors of the BoNT protease domain with a 17-residue peptide substrate led to arginine-arginine-glycine-cysteine having a basic tetrapeptide structure as the most potent inhibitor. When assayed in the presence of dithiothreitol (DTT), the inhibitory effect was drastically reduced. Replacing the terminal cysteine with one hydrophobic residue eliminated the DTT effect but with two hydrophobic residues made the pentapeptide a poor inhibitor. Replacing the first arginine with cysteine or adding an additional cysteine at the N terminus did not improve inhibition. When assessed using mouse brain lysates, the tetrapeptides also inhibited BoNT/A cleavage of the endogenous SNAP-25. The peptides penetrated the neuronal cell lines, N2A and BE(2)-M17, without adversely affecting metabolic functions as measured by ATP production and P-38 phosphorylation. Biological activity of the peptides persisted within cultured chick motor neurons and rat and mouse cerebellar neurons for more than 40 h and inhibited BoNT/A protease action inside the neurons in a dose- and time-dependent fashion. Our results define a tetrapeptide as the smallest peptide inhibitor in the backdrop of a large substrate protein of 200+ amino acids having multiple interaction regions with its cognate enzyme. The inhibitors should also be valuable candidates for drug development.

  8. pH regulates pore formation of a protease activated Vip3Aa from Bacillus thuringiensis.

    Science.gov (United States)

    Kunthic, Thittaya; Watanabe, Hirokazu; Kawano, Ryuji; Tanaka, Yoshikazu; Promdonkoy, Boonhiang; Yao, Min; Boonserm, Panadda

    2017-11-01

    Vip3Aa insecticidal protein is produced from Bacillus thuringiensis and exerts a broad spectrum of toxicity against lepidopteran insect species. Although Vip3Aa has been effectively used as part of integrated pest management strategies, the mechanism of the toxin remains unclear. Here, we investigated the effect of pH in a range from 5.0 to 10.0 on the pore-forming activity of the trypsin activated Vip3Aa (actVip3Aa) by in vitro pore-forming assays. Based on calcein release assay, actVip3Aa could permeabilize the artificial neutral liposomes under all the pH tested, except pH10.0. The maximum membrane permeability of actVip3Aa was detected at pH8.0 and the permeability decreased and abolished when exposing to acidic and alkaline conditions, respectively. The planar lipid bilayer experiment revealed that actVip3Aa formed ion channels at pH5.0-8.0 but no current signals were detected at pH10.0, consistent with the observation from calcein release assay. The toxin formed ion channels with a diameter of 1.4nm at pH8.0 and pore size was gradually decreased when reducing the pH. This study provided a view of the molecular mechanism of Vip3Aa by which the pore-forming activity is regulated by pH. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Attenuated vasodilator effectiveness of protease-activated receptor 2 agonist in heterozygous par2 knockout mice.

    Directory of Open Access Journals (Sweden)

    John C Hennessey

    Full Text Available Studies of homozygous PAR2 gene knockout mice have described a mix of phenotypic effects in vitro and in vivo. However, there have been few studies of PAR2 heterozygous (wild-type/knockout; PAR2-HET mice. The phenotypes of many hemi and heterozygous transgenic mice have been described as intermediates between those of wild-type and knockout animals. In our study we aimed to determine the effects of intermediary par2 gene zygosity on vascular tissue responses to PAR2 activation. Specifically, we compared the vasodilator effectiveness of the PAR2 activating peptide 2-furoyl-LIGRLO-amide in aortas of wild-type PAR2 homozygous (PAR2-WT and PAR2-HET mice. In myographs under isometric tension conditions, isolated aortic rings were contracted by alpha 1-adrenoeceptor agonist (phenylephrine, and thromboxane receptor agonist (U46619 and then relaxation responses by the additions of 2-furoyl-LIGRLO-amide, acetylcholine, and nitroprusside were recorded. A Schild regression analysis of the inhibition by a PAR2 antagonist (GB-83 of PAR2 agonist-induced aortic ring relaxations was used to compare receptor expression in PAR2-WT to PAR2-HET. PAR2 mRNA in aortas was measured by quantitative real-time PCR. In aortas contracted by either phenylephrine or U46619, the maximum relaxations induced by 2-furoyl-LIGRLO-amide were less in PAR2-HET than in the gender-matched PAR2-WT. GB-83 was 3- to 4-fold more potent for inhibition of 2fly in PAR2-HET than in PAR2-WT. PAR2 mRNA content of aortas from PAR2-HET was not significantly different than in PAR2-WT. Acetylcholine- and nitroprusside-induced relaxations of aortas from PAR2-HET were not significantly different than in PAR2-WT and PAR2 knockout. An interesting secondary finding was that relaxations induced by agonists of PAR2 and muscarinic receptors were larger in females than in males. We conclude that the lower PAR2-mediated responses in PAR2-HET aortas are consistent with evidence of a lower quantity of functional receptor expression, despite the apparently normal PAR2 mRNA content in PAR2-HET aortas.

  10. Electrical stimulation affects metabolic enzyme phosphorylation, protease activation and meat tenderization in beef

    DEFF Research Database (Denmark)

    Li, C.B.; Li, J.; Zhou, G.H.

    2012-01-01

    The objective of this study was to investigate the response of sarcoplasmic proteins in bovine longissimus muscle to low-voltage electrical stimulation (ES, 80 V, 35 s) after dressing and its contribution to meat tenderization at early postmortem time. Proteome analysis showed that ES resulted...... muscles up to 24 h. Immunohistochemistry and transmission electron microscopy further indicated that lysosomal enzymes were released at early postmortem time. ES also induced ultrastructural disruption of sarcomeres. In addition, ES accelerated (P

  11. Stimulation of endothelial cells by protease activity in commercial preparations of xanthine oxidase.

    Science.gov (United States)

    Ager, A; Wenham, D J; Gordon, J L

    1984-07-01

    The oxygen radical generating system of xanthine oxidase plus xanthine, which has been used as a model for the oxidative burst of activated granulocytes, is known to damage endothelium in vivo and in vitro. We previously observed effects (inhibited by catalase, and thus associated with the formation of H2O2) on several parameters of endothelial function, using a non-commercial preparation of xanthine oxidase. Our present study demonstrates that xanthine oxidase from two different commercial sources has additional effects on endothelial morphology and ion flux that are substrate-independent (i.e. produced in the absence of added xanthine) and are attributable to the presence of pancreatin (a crude enzyme mixture used in the commercial preparation of xanthine oxidase from milk). These effects are related to the tryptic activity of pancreatin and extend previous observations on the effects of neutral proteases on endothelial cells. Our results emphasise the practical point that studies on the effects of commercial xanthine oxidase preparations on endothelial cells must take account of their trypsin-like activity as well as their capacity to generate oxygen products.

  12. Fullerene Derivatives Strongly Inhibit HIV-1 Replication by Affecting Virus Maturation without Impairing Protease Activity.

    Science.gov (United States)

    Martinez, Zachary S; Castro, Edison; Seong, Chang-Soo; Cerón, Maira R; Echegoyen, Luis; Llano, Manuel

    2016-10-01

    Three compounds (1, 2, and 3) previously reported to inhibit HIV-1 replication and/or in vitro activity of reverse transcriptase were studied, but only fullerene derivatives 1 and 2 showed strong antiviral activity on the replication of HIV-1 in human CD4(+) T cells. However, these compounds did not inhibit infection by single-round infection vesicular stomatitis virus glycoprotein G (VSV-G)-pseudotyped viruses, indicating no effect on the early steps of the viral life cycle. In contrast, analysis of single-round infection VSV-G-pseudotyped HIV-1 produced in the presence of compound 1 or 2 showed a complete lack of infectivity in human CD4(+) T cells, suggesting that the late stages of the HIV-1 life cycle were affected. Quantification of virion-associated viral RNA and p24 indicates that RNA packaging and viral production were unremarkable in these viruses. However, Gag and Gag-Pol processing was affected, as evidenced by immunoblot analysis with an anti-p24 antibody and the measurement of virion-associated reverse transcriptase activity, ratifying the effect of the fullerene derivatives on virion maturation of the HIV-1 life cycle. Surprisingly, fullerenes 1 and 2 did not inhibit HIV-1 protease in an in vitro assay at the doses that potently blocked viral infectivity, suggesting a protease-independent mechanism of action. Highlighting the potential therapeutic relevance of fullerene derivatives, these compounds block infection by HIV-1 resistant to protease and maturation inhibitors. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  13. Relative contribution of matrix metalloprotease and cysteine protease activities to cytokine-stimulated articular cartilage degradation

    DEFF Research Database (Denmark)

    Sondergaard, B C; Henriksen, K; Wulf, H

    2006-01-01

    (GAG), hydroxyproline, and cross-linked C-telopeptide fragments of type II collagen (CTX-II), which were compared to immunohistochemical evaluations of proteoglycans and CTX-II. We assessed MMP expression by gelatine zymography and CK expression by immunohistochemistry. In vivo, CTX-II release...... was measured from CK-deficient mice. RESULTS: OSM and TNF-alpha combined induced significant (Pzymography, and CK expression...

  14. Potential novel targets: Protease-activated receptors in idiopathic pulmonary fibrosis

    NARCIS (Netherlands)

    Lin, C.

    2015-01-01

    Idiopathic pulmonary fibrosis (IPF) is the most devastating diffuse fibrosing lung disease of unknown etiology. IPF patients suffer from severe breathlessness caused by decreasing lung compliance eventually leading to respiratory failure and death. The prognosis of IPF is devastating: there is only

  15. Anti-HIV-1 protease activities of crude extracts of some Garcinia ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-22

    Mar 22, 2010 ... the life cycle of the virus is the HIV-1 protease (PR) which process viral proteins into functional enzymes and structural proteins. HIV-1 PR plays a key role in the maturity and infectivity of the virus hence it has become an important target in HIV drug development (Kohl et al., 1988). HIV-1. PR function as a ...

  16. The diagnostic potential of salivary protease activities in periodontal health and disease

    NARCIS (Netherlands)

    Thomadaki, K.; Bosch, J.A.; Oppenheim, F.G.; Helmerhorst, E.J.

    2013-01-01

    Periodontal disease is characterised by proteolytic processes involving enzymes that are released by host immune cells and periodontal bacteria. These enzymes, when detectable in whole saliva, may serve as valuable diagnostic markers for disease states and progression. Because the substrate

  17. Strain improvement of Aspergillus niger for enhanced lipase production.

    Science.gov (United States)

    Sandana Mala, John Geraldine; Kamini, Numbi R.; Puvanakrishnan, Rengarajulu

    2001-08-01

    The enhancement of lipase production from Aspergillus niger was attempted by ultraviolet (UV) and nitrous acid mutagenesis, and the mutants were selected on media containing bile salts. Nitrous acid mutants exhibited increased efficiency for lipase production when compared with UV mutants in submerged fermentation. The hyperproducing UV and nitrous acid mutants were further subjected to a second step of mutagenesis to devise an economical and ecofriendly technique for lipase production by the effective use of hydrocarbons. One percent kerosene was found to be optimal for lipase production, and one of the mutant strains NAII exhibited 2.53 times more increased lipase activity than the parental strain did. This investigation indicates a possible role for the A. niger mutant strains in the biodegradation of oil-polluted environments for the development of ecofriendly technologies.

  18. Ultramylonite generation via phase mixing in high-strain experiments

    Science.gov (United States)

    Cross, A. J.; Skemer, P.

    2017-03-01

    Dynamic recrystallization and phase mixing are considered to be important processes in ductile shear zone formation, as they collectively enable a permanent transition to the strain-weakening, grain-size sensitive deformation regime. While dynamic recrystallization is well understood, the underlying physical processes and timescales required for phase mixing remain enigmatic. Here, we present results from high-strain phase mixing experiments on calcite-anhydrite composites. A poorly mixed starting material was synthesized from fine-grained calcite and anhydrite powders. Samples were deformed in the Large Volume Torsion apparatus at 500°C and shear strain rates of 5 × 10-5 to 5 × 10-4 s-1, to finite shear strains of up to γ = 57. Microstructural evolution is quantified through analysis of backscattered electron images and electron backscatter diffraction data. During deformation, polycrystalline domains of the individual phases are geometrically stretched and thinned, causing an increase in the spatial density of interphase boundaries. At moderate shear strains (γ ≥ 6), domains are so severely thinned that they become "monolayers" of only one or two grain's width and form a thin compositional layering. Monolayer formation is accompanied by a critical increase in the degree of grain boundary pinning and, consequently, grain-size reduction below the theoretical limit established by the grain-size piezometer or deformation mechanism field boundary. Ultimately, monolayers neck and disaggregate at high strains (17 <γ <57) to complete the phase mixing process. This "geometric" phase mixing mechanism is consistent with observations of mylonites, where layer (i.e., foliation) formation is associated with strain localization, and layers are ultimately destroyed at the mylonite-ultramylonite transition.

  19. [The difference in specific humoral immune responses induced with the attenuated equine infectious anemia vaccine strain and virulent strain.].

    Science.gov (United States)

    Zhu, Zhen-Ying; Lin, Yue-Zhi; Wang, Yu-Hong; Zhao, Li-Ping; Zhu, Yuan-Mao; Zhou, Jian-Hua

    2009-12-01

    To disclose the potential roles of humoral immune response in the EIAV vaccine-induced protective immunity. In this study, major parameters of humoral immunity be compared between horses inoculated with the EIAV vaccine strain and the pathogenic virulent strain. Experimental horses were randomly assigned into the group inoculated with the vaccine strain EIAV(DLV); (the vaccinated group) and the group inoculated with sub-morbigenous dose of virulent strain EIAV(Liao); (the inapparent infection group). Humoral immunity parameters, including binding endpoint titer and avidity index of antibodies to the envelop protein (Env) and the capsid protein (P26), and the conformation-dependent index of the Env antibody, were assayed and compared between these two groups by using ELISA. Neutralizing antibodies to the EIAV vaccine strain and a pathogenic strain were simultaneously detected by using plaque forming unite assay (PFU) and reverse transcriptase activity assay, respectively. In general, all humoral parameters increased with a time-dependent manner in both the vaccinated and the inapparent infection group. However, significantly higher antibody activities for P26 binding endpoint titer and Env avidity index were detected in the vaccinated group within 2 months post infection (Pinfection group throughout the entire observation period (Pinfected horses (P<0.01 for EIAV(FDDV); and P<0.05 for EIAV(DLV34);). Statistically significant differences in EIAV-specific binding antibodies and the neutralizing antibody are detected between animals induced with the EIAV vaccine strain and the virulent strain. Importantly, the significantly early and strong responses in the neutralizing antibody and the conformation-dependent Env antibody induced by the vaccine implicate special roles these antibodies playing in EIAV vaccine-induced immune protection.

  20. Antagonistic Activity of Three Newly Isolated Yeast Strains from the Surface of Fruits

    Directory of Open Access Journals (Sweden)

    Ortansa Csutak

    2013-01-01

    Full Text Available Three Metschnikowia pulcherrima strains isolated from white grapes(strains designated SG1 and SG2 and cherries (strain CPM1 from Romania were tested for antagonistic activity against natural and reference yeasts, fungi and E. coli. The best results were obtained for SG2 strain against the following microbes isolated from natural environments: yeasts Candida tropicalis OT4 and Candida albicans Cc, and fungal strains Botrytis cinerea BCS and BCF1. Using 2 % sodium hydrogen carbonate and 1 or 2 % calcium chloride, antimicrobial activities of strains SG1 and SG2 were maintained or even enhanced, while strain CPM1 was less influenced. Antimicrobial tests revealed four types of colonies and halos of strains SG1, SG2 and CPM1 reflecting differences in iron immobilization under similar growth conditions. Antifungal activity and the level of pigment production increased at 25 °C, and the largest diffusible pigment area was obtained by strain SG2, which altered Botrytis conidia germination and induced modifications of mycelium. Competition for iron seems to be the major mechanism of antagonistic action of our strains, which is reduced/absent under iron chloride addition. Lowering of antifungal activity by heating or proteolytic treatment indicates that a protein might also be involved. The inhibitory activity of yeast supernatants was less important, suggesting a cell-related mechanism. When combined, strains SG1 and SG2 had synergistic activity, which was reduced in the presence of CPM1 due to possible production of an inhibitory compound.

  1. Local strain exerted on Nb3Sn filaments in an ITER strand

    International Nuclear Information System (INIS)

    Osamura, Kozo; Machiya, Shutaro; Harjo, Stefanus; Nakamoto, Tatsushi; Cheggour, Najib; Nijhuis, Arend

    2015-01-01

    As part of an international project to benchmark facilities for measuring the strain dependence of critical current in International Thermonuclear Experimental Reactor (ITER) Nb 3 Sn strands, direct measurement of local strain exerted on Nb 3 Sn filaments was attempted at cryogenic temperature by means of a pulsed neutron technique. The lattice axial strain increased linearly with a slope close to unity against applied strain, while the thermal axial strain was −0.22% at 8.5 K. As a result, the force-free strain was evaluated to be 0.22–0.23%. This key parameter should provide an accurate estimate of the peak location of critical current versus applied strain. The lattice transverse strain decreased linearly as a function of applied strain with a slope of 0.33–0.34. The lattice strains of the Nb and Cu components were also measured and their behavior was analyzed by computing diffraction elastic moduli based on micromechanics theories. The stress–strain curve calculated according to the rule of mixtures described quite well the macroscopic curve measured for the present ITER Nb 3 Sn strand. (paper)

  2. Effect of strain field on displacement cascade in tungsten studied by molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Gao, N., E-mail: ning.gao@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Z.G., E-mail: zhgwang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Gao, X. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); He, W.H. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Cui, M.H.; Pang, L.L.; Zhu, Y.B. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2016-10-01

    Using atomistic methods, the coupling effect of strain field and displacement cascade in body-centered cubic (BCC) tungsten is directly simulated by molecular dynamics (MD) simulations at different temperatures. The values of the hydrostatic and uniaxial (parallel or perpendicular to primary knock-on atom (PKA) direction) strains are from −2% to 2% and the temperature is from 100 to 1000 K. Because of the annealing effect, the influence of strain on radiation damage at low temperature has been proved to be more significant than that at high temperature. When the cascade proceeds under the hydrostatic strain, the Frenkel Pair (FP) production, the fraction of defect in cluster and the average size of the defect cluster, all increase at tensile state and decrease at compressive state. When the cascade is under uniaxial strain, the effect of strain parallel to PKA direction is less than the effect of hydrostatic strain, while the effect of strain perpendicular to PKA direction can be negligible. Under the uniaxial strain along 〈1 1 1〉 direction, the SIA and SIA cluster is observed to orientate along the strain direction at tensile state and the uniaxial compressive strain with direction perpendicular to 〈1 1 1〉 has led to the similar preferred nucleation. All these results indicate that under irradiation, the tensile state should be avoided for materials used in nuclear power plants.

  3. Experimental Investigation of Strain Rate and Temperature Dependent Response of an Epoxy Resin Undergoing Large Deformation

    Science.gov (United States)

    Tamrakar, Sandeep; Ganesh, Raja; Sockalingam, Subramani; Haque, Bazle Z.; Gillespie, John W.

    2018-01-01

    Experimental investigation of the effect of strain rate and temperature on large inelastic deformation of an epoxy resin is presented. Uniaxial compression tests were conducted on DER 353 epoxy resin at strain rates ranging from 0.001 to 12,000/s. Experimental results showed significant rate sensitivity in yield stress, which increased from 85 MPa at 0.001/s to 220 MPa at 12,000/s strain rate. Thermal softening became more prominent as the strain rate was increased, resulting in complete absence of strain hardening at high strain rates. Rise in temperature under high strain rate, due to adiabatic heating, was estimated to increase above glass transition temperature (T g ). A series of compression tests carried out at temperatures ranging from ambient to T g + 80 °C showed yield stress vanishing at T g . Above T g , the epoxy became completely rubbery elastic at quasi-static loading rate. Epoxy became less sensitive to strain rate as the temperature was increased further above T g . The strain rate and temperature dependent yield behavior of the epoxy resin is predicted using Ree-Eyring model.

  4. Rhizobium Strain Effects on Yield and Bleeding Sap Amino Compounds in Pisum sativum

    DEFF Research Database (Denmark)

    Rosendahl, Lis

    1984-01-01

    Bleeding sap composition, dry matter production and N distribution in pea (P. sativum L. cv. Bodil) grown with and without nitrate and nodulated with either R. leguminosarum strain 128c53 or strain 1044 were compared. Nitrate increased the total dry matter production of both symbioses, but decrea......Bleeding sap composition, dry matter production and N distribution in pea (P. sativum L. cv. Bodil) grown with and without nitrate and nodulated with either R. leguminosarum strain 128c53 or strain 1044 were compared. Nitrate increased the total dry matter production of both symbioses...... relative to the total N-accumulation was greater with strain 128c53 due to a higher production of nodule tissue. The root bleeding sap of the symbiosis with the greater yield (strain 1044) contained high levels of asparagine and aspartic acid. In the 128c53 symbiosis, glutamine plus homoserine accounted...

  5. Development of Industrial Yeast Platform Strains

    DEFF Research Database (Denmark)

    Bergdahl, Basti; Dato, Laura; Förster, Jochen

    2014-01-01

    Most of the current metabolic engineering projects are carried out using laboratory strains as the starting host. Although such strains are easily manipulated genetically, their robustness does not always meet the requirements set by industrial fermentation conditions. In such conditions, the cel...... screening of the 36 industrial and laboratory yeast strains. In addition, progress in the development of molecular biology methods for generating the new strains will be presented....

  6. Right ventricular strain in heart failure: Clinical perspective.

    Science.gov (United States)

    Tadic, Marijana; Pieske-Kraigher, Elisabeth; Cuspidi, Cesare; Morris, Daniel A; Burkhardt, Franziska; Baudisch, Ana; Haßfeld, Sabine; Tschöpe, Carsten; Pieske, Burket

    2017-10-01

    The number of studies demonstrating the importance of right ventricular remodelling in a wide range of cardiovascular diseases has increased in the past two decades. Speckle-tracking imaging provides new variables that give comprehensive information about right ventricular function and mechanics. In this review, we summarize current knowledge of right ventricular mechanics in heart failure with reduced ejection fraction and preserved ejection fraction. We searched PubMed, MEDLINE, Ovid and Embase databases for studies published from January 2000 to December 2016 in the English language using the following keywords: "right ventricle"; "strain"; "speckle tracking"; "heart failure with reduced ejection fraction"; and "heart failure with preserved ejection fraction". Investigations showed that right ventricular dysfunction is associated with higher cardiovascular and overall mortality in patients with heart failure, irrespective of ejection fraction. The number of studies investigating right ventricular strain in patients with heart failure with reduced ejection fraction is constantly increasing, whereas data on right ventricular mechanics in patients with heart failure with preserved ejection fraction are limited. Given the high feasibility, accuracy and clinical implications of right ventricular strain in the population with heart failure, it is of great importance to try to include the evaluation of right ventricular strain as a regular part of each echocardiographic examination in patients with heart failure. However, further investigations are necessary to establish right ventricular strain as a standard variable for decision-making. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  7. A strain gradient plasticity theory with application to wire torsion

    KAUST Repository

    Liu, J. X.

    2014-06-05

    Based on the framework of the existing strain gradient plasticity theories, we have examined three kinds of relations for the plastic strain dependence of the material intrinsic length scale, and thus developed updated strain gradient plasticity versions with deformation-dependent characteristic length scales. Wire torsion test is taken as an example to assess existing and newly built constitutive equations. For torsion tests, with increasing plastic strain, a constant intrinsic length predicts too high a torque, while a decreasing intrinsic length scale can produce better predictions instead of the increasing one, different from some published observations. If the Taylor dislocation rule is written in the Nix-Gao form, the derived constitutive equations become singular when the hardening exponent gets close to zero, which seems questionable and calls for further experimental clarifications on the exact coupling of hardening due to statistically stored dislocations and geometrically necessary dislocations. Particularly, when comparing the present model with the mechanism-based strain gradient plasticity, the present model satisfies the reciprocity relation naturally and gives different predictions even under the same parameter setting. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  8. Effect of strain rate on bake hardening response of BH220 steel

    Directory of Open Access Journals (Sweden)

    Das Anindya

    2015-01-01

    Full Text Available This study aims at understanding the bake hardening ability of ultra low carbon BH220 steel at different strain rates. The as-received material has been pre-strained to four different levels and then deformed in tension under (a as pre-strained state and (b after baking at 170 ∘C for 20 minutes, at three different strain rates of 0.001, 0.1 and 100/s. In both the conditions, yield stress increased with pre-strain and strain rate, but bake hardening ability was found to decrease when strain rate was increased. The strain rate sensitivity of the material was also found to decrease with bake hardening. Generation of dislocation forests and their subsequent immobility during baking treatment enables them to act as long range obstacles during further deformation. At higher strain rates, less amount of dislocations are produced which can interact with themselves and produce hardening, because of which bake hardening ability and the strain rate drops. A dislocation based strengthening model, as proposed by Larour et al. 2011 [7], was used to predict the yield stress values obtained at different conditions. The equation produced excellent co-relation with the experimental data.

  9. Characterization of Clostridium thermocellum strains with disrupted fermentation end-product pathways

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Veen, Douwe [ORNL; Lo, Jonathan [Dartmouth College; Brown, Steven D [ORNL; Johnson, Courtney M [ORNL; Tschaplinski, Timothy J [ORNL; Martin, Madhavi Z [ORNL; Engle, Nancy L [ORNL; Van den Berg, Robert A [Katholieke University Leuven, Belgium; Argyros, Aaron [Mascoma Corporation; Caiazza, Nicky [Mascoma Corporation; Guss, Adam M [ORNL; Lynd, Lee R [Thayer School of Engineering at Dartmouth

    2013-01-01

    Clostridium thermocellum is a thermophilic, cellulolytic anaerobe that is a candidate microorganism for industrial biofuels production. Strains with mutations in genes associated with production of L-lactate (Dldh) and/or acetate (Dpta) were characterized to gain insight into the intracellular processes that convert cellobiose to ethanol and other fermentation end-products. Cellobiose-grown cultures of the Dldh strain had identical biomass accumulation, fermentation end-products, transcription profile, and intracellular metabolite concentrations compared to its parent strain (DSM1313 Dhpt Dspo0A). The Dpta-deficient strain grew slower and had 30 % lower final biomass concentration compared to the parent strain, yet produced 75% more ethanol. A Dldh Dpta double-mutant strain evolved for faster growth had a growth rate and ethanol yield comparable to the parent strain, whereas its biomass accumulation was comparable to Dpta. Free amino acids were secreted by all examined strains, with both Dpta strains secreting higher amounts of alanine, valine, isoleucine, proline, glutamine, and threonine. Valine concentration for Dldh Dpta reached 5 mM by the end of growth, or 2.7 % of the substrate carbon utilized. These secreted amino acid concentrations correlate with increased intracellular pyruvate concentrations, up to sixfold in the Dpta and 16-fold in the Dldh Dpta strain. We hypothesize that the deletions in fermentation end-product pathways result in an intracellular redox imbalance, which the organism attempts to relieve, in part by recycling NADP* through increased production of amino acids.

  10. Characterization of Clostridium thermocellum strains with disrupted fermentation end product pathways

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Veen, Douwe [ORNL; Lo, Jonathan [Dartmouth College; Brown, Steven D [ORNL; Johnson, Courtney M [ORNL; Tschaplinski, Timothy J [ORNL; Martin, Madhavi Z [ORNL; Engle, Nancy L [ORNL; Argyros, Aaron [Mascoma Corporation; Van den Berg, Robert A [Katholieke University Leuven, Belgium; Caiazza, Nicky [Mascoma Corporation; Guss, Adam M [ORNL; Lynd, Lee R [Thayer School of Engineering at Dartmouth

    2013-01-01

    Clostridium thermocellum is a thermophilic, cellulolytic anaerobe that is a candidate microorganism for industrial biofuels production. Strains with mutations in genes associated with production of Llactate ( ldh) and/or acetate ( pta) were characterized to gain insight into the intracellular processes that convert cellobiose to ethanol and other fermentation end products. Cellobiose-grown cultures of the ldh strain had identical biomass accumulation, fermentation end products, transcription profile and intracellular metabolite concentrations compared to its parent strain (DSM1313 hpt spo0A). The pta-deficient strain grew slower and had 30% lower final biomass concentration compared to the parent strain, yet produced 75% more ethanol. A ldh pta double mutant strain evolved for faster growth had growth rate and ethanol yield comparable to the parent strain, whereas its biomass accumulation was comparable to pta. Free amino acids were secreted by all examined strains, with both pta strains secreting higher amounts of alanine, valine, isoleucine, proline, glutamine, and threonine. Valine concentration for ldh pta reached 5 mM by the end of growth, or 2.7% of the substrate carbon utilized. These secreted amino acid concentrations correlate with increased intracellular pyruvate concentrations, up to 6-fold in the pta and 16-fold in the ldh pta strain. We hypothesize that the deletions in fermentation end product pathways result in an intracellular redox imbalance, which the organism attempts to relieve, in part by recycling NADP+ through increased production of amino acids.

  11. Strain engineering of van der Waals heterostructures

    NARCIS (Netherlands)

    Vermeulen, Paul A.; Mulder, Jefta; Momand, Jamo; Kooi, Bart J.

    2018-01-01

    Modifying the strain state of solids allows control over a plethora of functional properties. The weak interlayer bonding in van der Waals (vdWaals) materials such as graphene, hBN, MoS2, and Bi2Te3 might seem to exclude strain engineering, since strain would immediately relax at the vdWaals

  12. drug resistant strains of Salmonella enterica

    African Journals Online (AJOL)

    Conclusions: The aqueous extract of Thonningia sanguinea can provide an alternative therapy for the treatment of salmonellosis, mainly for typhoid fever caused by MDR strains of S. Typhi.The extract also inhibits S.Hadar a MDR emerging strain in Ivory Coast. Keywords: Thonningia sanguinea; Salmonella, MDR strains, ...

  13. Modal strain energies in COSMIC NASTRAN

    Science.gov (United States)

    Snyder, B. D.; Venkayya, V. B.

    1989-01-01

    A computer program was developed to take a NASTRAN output file from a normal modes analysis and calculate the modal strain energies of selected elements. The FORTRAN program can determine the modal strain energies for CROD, CBAR, CELAS, CTRMEM, CQDMEM2, and CSHEAR elements. Modal strain energies are useful in estimating damping in structures.

  14. Engineering piezoresistivity using biaxially strained silicon

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Richter, Jacob; Brandbyge, Mads

    2008-01-01

    of the piezocoefficient on temperature and dopant density is altered qualitatively for strained silicon. In particular, we find that a vanishing temperature coefficient may result for silicon with grown-in biaxial tensile strain. These results suggest that strained silicon may be used to engineer the iezoresistivity...

  15. Phenotypic characterization of Lactobacillus strains isolated from ...

    African Journals Online (AJOL)

    Thirty three strains of Lactobacillus were isolated from human milk and infant faeces, animal (cow and goat) milks and from plants (Anagalis arvensis and Bromus mango species). The various strains were identified based on phenotypic tests. Amongst them, 12 strains belonged to group 1, which comprised L. acidophilus, ...

  16. Solubilisation of inorganic phosphates by inoculant strains from tropical legumes

    Directory of Open Access Journals (Sweden)

    Leandro Marciano Marra

    2011-10-01

    Full Text Available Microbial solubilisation of low soluble inorganic phosphates is an important process contributing for the phosphorus available to plants in tropical soils. This study evaluates the ability of inoculant strains for tropical legumes to solubilise inorganic phosphates of low solubility that are found in tropical soils. Seven strains of Leguminosae nodulating bacteria (LNB were compared with one another and with a non-nodulating positive control, Burkholderia cepacia (LMG 1222T. Four of the strains are used as inoculants for cowpeas (Vigna unguiculata (Bradyrhizobium sp. UFLA 03-84; Bradyrhizobium elkani INPA 03-11B and Bradyrhizobium japonicum BR3267 or for common beans (Phaseolus vulgaris (Rhizobium tropici CIAT 899T. Rhizobium etli UFLA 02-100 and Rhizobium leguminosarum 316C10a are also efficient nodulators of beans and Cupriavidus taiwanensis LMG 19424T nodulates on Mimosa pudica. Two experiments, with solid and liquid media, were performed to determine whether the strains were able to solubilise CaHPO4, Al(H2PO43 or FePO4.2H2O. On solid GELP medium none of the strains dissolved FePO4.2H2O, but LMG 1222, UFLA 03-84 and CIAT 899 solubilised CaHPO4 particularly well. These strains, along with LMG 19424 and BR 3267, were also able to increase the solubility of Al(H2PO43. In liquid GELP medium, LMG 1222 solubilised all phosphate sources, but no legume nodulating strain could increase the solubility of Al(H2PO43. The strains CIAT 899 and UFLA 02-100 were the only legume nodulating bacteria able to solubilise the other phosphate sources in liquid media, dissolving both CaHPO4 and FePO4.2H2O. There was a negative correlation between the pH of the culture medium and the concentration of soluble phosphate when the phosphorus source was CaHPO4 or FePO4.2H2O. The contribution of these strains to increasing the phosphorus nutrition of legumes and non-legume plant species should be investigated further by in vivo experiments.

  17. Strain rate effect on sooting characteristics in laminar counterflow diffusion flames

    KAUST Repository

    Wang, Yu

    2016-01-20

    The effects of strain rate, oxygen enrichment and fuel type on the sooting characteristics of counterflow diffusion flames were studied. The sooting structures and relative PAH concentrations were measured with laser diagnostics. Detailed soot modeling using recently developed PAH chemistry and surface reaction mechanism was performed and the results were compared with experimental data for ethylene flames, focusing on the effects of strain rates. The results showed that increase in strain rate reduced soot volume fraction, average size and peak number density. Increase in oxygen mole fraction increased soot loading and decreased its sensitivity on strain rate. The soot volume fractions of ethane, propene and propane flames were also measured as a function of global strain rate. The sensitivity of soot volume fraction to strain rate was observed to be fuel dependent at a fixed oxygen mole fraction, with the sensitivity being higher for more sooting fuels. However, when the soot loadings were matched at a reference strain rate for different fuels by adjusting oxygen mole fraction, the dependence of soot loading on strain rate became comparable among the tested fuels. PAH concentrations were shown to decrease with increase in strain rate and the dependence on strain rate is more pronounced for larger PAHs. Soot modeling was performed using detailed PAH growth chemistry with molecular growth up to coronene. A qualitative agreement was obtained between experimental and simulation results, which was then used to explain the experimentally observed strain rate effect on soot growth. However, quantitatively, the simulation result exhibits higher sensitivity to strain rate, especially for large PAHs and soot volume fractions.

  18. Antigenic differentiation of classical swine fever vaccinal strain PAV-250 from other strains, including field strains from Mexico.

    Science.gov (United States)

    Mendoza, Susana; Correa-Giron, Pablo; Aguilera, Edgar; Colmenares, Germán; Torres, Oscar; Cruz, Tonatiuh; Romero, Andres; Hernandez-Baumgarten, Eliseo; Ciprián, Abel

    2007-10-10

    Twenty-nine classical swine fever virus (CSFv) strains were grown in the PK15 or SK6 cell lines. Antigenic differentiation studies were performed using monoclonal antibodies (McAbs), produced at Lelystad (CDI-DLO), The Netherlands. The monoclonals which were classified numerically as monoclonals 2-13. Epitope map patterns that resulted from the reactivity with McAbs were found to be unrelated to the pathogenicity of the viruses studied. Antigenic determinants were recognized by McAbs 5 and 8, were not detected in some Mexican strains; however, sites for McAb 6 were absent in all strains. The PAV-250 vaccine strain was recognized by all MAbs, except by MAb 6. Furthermore, the Chinese C-S vaccine strain was found to be very similar to the GPE(-) vaccine. None of the studied Mexican vaccines or field strains was found to be similar to the PAV-250 vaccine strain.

  19. High incidence of multidrug-resistant strains of methicill inresistant ...

    African Journals Online (AJOL)

    Infections of methicillin-resistant Staphylococcus aureus (MRSA) are becoming an increasingly concerning clinical problem. The aim of this study was to assess the development of multidrug resistant strains of MRSA from clinical samples andpossibilities for reducing resistance. This study included a total of seventy-five (75) ...

  20. Stress-Strain Curves for High-Performance Fiber Reinforced ...

    African Journals Online (AJOL)

    Steel fiber reinforced concrete (SFRC) is increasingly being used day by day as a structural material for various applications. The complete stress-strain curve of this material in compression is needed for the analysis and design of structural elements. An experimental investigation was carried out to generate the complete ...

  1. Strain improvement in dye decolourising mutants of Mucor mucedo ...

    African Journals Online (AJOL)

    The fusant MMFu3 showed very good increase in the production of three enzymes protease (1.90 U/ml), peroxidase (1100 U/ml) and laccase (200 U/ml) when compared to the two parent strains proving that the higher enzymatic secretions are responsible for the decolourisation activity. In protease isozyme analysis, fusants ...

  2. Computational Strain Gradient Crystal Plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2011-01-01

    element solution method is presented, which delivers the slip-rate field and the velocity-field based on two minimum principles. Some plane deformation problems relevant for certain specific orientations of a face centered cubic crystal under plane loading conditions are studied, and effective in......A model for strain gradient crystal visco-plasticity is formulated along the lines proposed by Fleck andWillis (2009) for isotropic plasticity. Size-effects are included in the model due to the addition of gradient terms in both the free energy as well as through a dissipation potential. A finite...

  3. Monoclonal antibodies to Toxoplasma gondii strain 119 identify recently isolated Danish strains as one group

    DEFF Research Database (Denmark)

    Jensen, L.; Petersen, E.; Henriksen, S.A.

    1998-01-01

    Four mAb raised against the Danish Toxoplasma gondii strain 119, were selected by screening hybridoma supernatants by indirect immunofluorescence against tachyzoites of the RH strain in order to obtain strain restricted markers. Strain restriction extended beyond discrimination of the 119 and RH...

  4. The role of nitrogen uptake on the competition ability of three vineyard Saccharomyces cerevisiae strains.

    Science.gov (United States)

    Vendramini, Chiara; Beltran, Gemma; Nadai, Chiara; Giacomini, Alessio; Mas, Albert; Corich, Viviana

    2017-10-03

    Three vineyard strains of Saccharomyces cerevisiae, P301.4, P304.4 and P254.12, were assayed in comparison with a commercial industrial strain, QA23. The aim was to understand if nitrogen availability could influence strain competition ability during must fermentation. Pairwise-strain fermentations and co-fermentations with the simultaneous presence of the four strains were performed in synthetic musts at two nitrogen levels: control nitrogen condition (CNC) that assured the suitable assimilable nitrogen amount required by the yeast strains to complete the fermentation and low nitrogen condition (LNC) where nitrogen is present at very low level. Results suggested a strong involvement of nitrogen availability, as the frequency in must of the vineyard strains, respect to QA23, in LNC was always higher than that found in CNC. Moreover, in CNC only strain P304.4 reached the same strain frequency as QA23. P304.4 competition ability increased during the fermentation, indicating better performance when nitrogen availability was dropping down. P301.4 was the only strain sensitive to QA23 killer toxin. In CNC, when it was co-inoculated with the industrial strain QA23, P301.4 was never detected. In LNC, P301.4 after 12h accounted for 10% of the total population. This percentage increased after 48h (20%). Single-strain fermentations were also run in both conditions and the nitrogen metabolism further analyzed. Fermentation kinetics, ammonium and amino-acid consumptions and the expression of genes under nitrogen catabolite repression evidenced that vineyard yeasts, and particularly strain P304.4, had higher nitrogen assimilation rate than the commercial control. In conclusion, the high nitrogen assimilation rate seems to be an additional strategy that allowed vineyard yeasts successful competition during the growth in grape musts. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. EDITORIAL: Excelling under strain: band engineering in nanomaterials Excelling under strain: band engineering in nanomaterials

    Science.gov (United States)

    Demming, Anna

    2013-08-01

    A little stress or strain has been known to improve the performance of athletes, actors and of course nanomaterials alike. In fact strain in silicon is now a major engineering tool for improving the performance of devices, and is ubiquitously used in device design and fabrication. Strain engineering alters a material's band structure, a model of electron behaviour that describes how as atoms come together in a solid, their discrete electron orbitals overlap to ultimately give rise to bands of allowed energy levels. In a strained crystal lattice of silicon or silicon germanium the distance between atoms in the lattice is greater than usual and the bands of allowed energy levels change. This July marks 100 years since Bohr submitted his paper 'On the constitution of atoms and molecules' [1] where he describes the structure of the atom in terms of discrete allowed energy levels. The paper was a seminal contribution to the development of quantum mechanics and laid the initial theoretical precepts for band gap engineering in devices. In this issue Nrauda and a collaboration of researchers in Europe and Australia study the growth of defect-free SiGe islands on pre-patterned silicon [2]. They analyse the strain in the islands and determine at what point lattice dislocations set in with a view to informing implementation of strain engineering in devices. The effects of strain on band structure in silicon and germanium were already studied and reported in the 1950s [3, 4]. Since then the increasing focus on nanoscale materials and the hunger for control of electronic properties has prompted further study of strain effects. The increased surface area to volume ratio in nanostructures changes the strain behaviour with respect to bulk materials, and this can also be exploited for handling and fine tuning strain to manipulate material properties. It is perhaps no surprise that graphene, one of the most high-profile materials in current nanotechnology research, has attracted

  6. Spontaneous abortion and physical strain around implantation

    DEFF Research Database (Denmark)

    Hjollund, N H; Jensen, Tina Kold; Bonde, Jens Peter

    2000-01-01

    Existing studies of physical strain and spontaneous abortion are mainly retrospective or based only on pregnancies that have survived the first trimester. Furthermore, almost all studies have relied on averaged measures of physical strain, which tend to blur an effect if peak values during short...... pregnancy the women recorded physical strain prospectively in a structured diary. Physical strain around the time of implantation was associated with later spontaneous abortion. The adjusted risk ratio for women who reported physical strain higher than average at day 6 to 9 after the estimated date...

  7. Local strains in waste tank deflagration analysis

    International Nuclear Information System (INIS)

    Bryan, B.J.; Flanders, H.E. Jr.

    1993-01-01

    In recent years extensive effort has been expended to qualify buried nuclear waste storage tanks under accident conditions. One of these conditions is deflagration of the combustible gases which may build up over time. While much work has been done to calculate the general strain state, less effort has been made to address the local strains at structural discontinuities. An analytical method is presented for calculating these local strains and combining them with the general strain state. A closed form solution of the local strains is compared to a finite element solution

  8. On lower order strain gradient plasticity theories

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Hutchinson, J. W.

    2003-01-01

    the tangent moduli governing increments of stress and strain. It is shown that the modification is far from benign from a mathematical standpoint, changing the qualitative character of solutions and leading to a new type of localization that is at odds with what is expected from a strain gradient theory......By way of numerical examples, this paper explores the nature of solutions to a class of strain gradient plasticity theories that employ conventional stresses, equilibrium equations and boundary conditions. Strain gradients come into play in these modified conventional theories only to alter....... The findings raise questions about the physical acceptability of this class of strain gradient theories....

  9. Sensibility of different wheat varieties (strains) to Ar+ implantation

    International Nuclear Information System (INIS)

    Cui Huanhu; Jing Hua; Ma Aiping; Kang Xiuli; Yang Liping; Huang Mingjing; Ma Buzhou; Shanxi Academy of Agricultural Sciences, Taiyuan

    2005-01-01

    The sensibility of different wheat varieties (strains) to Ar + implantation was studied. The results showed that the survival rate of 21 wheat varieties (strains) at the dose of 6 x 10 16 Ar + /cm 2 could be divided into five groups: surplus sensitive varieties (strains), sensitive varieties (strains), transitional varieties (strains), obtuse varieties (strains) and surplus obtuse varieties (strains). The sensibility of wheat varieties (strains) to Ar + injection is high-moisture-fertility wheat varieties (strains) > medium-moisture-fertility wheat varieties (strains) > dry land wheat varieties (strains). The study has provided theoretical basis in induced mutation medial lethal dose of different wheat varieties (strains) to Ar + implantation. (authors)

  10. Azospirillum sp. strain B510 enhances rice growth and yield.

    Science.gov (United States)

    Isawa, Tsuyoshi; Yasuda, Michiko; Awazaki, Hirotoshi; Minamisawa, Kiwamu; Shinozaki, Satoshi; Nakashita, Hideo

    2010-01-01

    Inoculation experiments with the endophytic bacterium Azospirillum sp. strain B510, an isolate from surface-sterilized stems of field-grown rice, were conducted in pots in a greenhouse, and in paddy fields in Hokkaido, Japan. B510 significantly enhanced the growth of newly generated leaves and shoot biomass under greenhouse conditions. When rice seedlings were treated with 1×10(8) CFU ml(-1), then transplanted to paddy fields, tiller numbers and seed yield significantly increased. Azospirillum sp. strain B510 is a promising bacterial inoculant for plant growth promotion and agricultural practices.

  11. Interaction of pea (Pisum sativum L.) lectins with rhizobial strains.

    Science.gov (United States)

    Bajaj, M; Soni, G; Singh, C K

    2001-01-01

    Lectins from two varieties (PG-3 and LFP-48) of pea have been purified by affinity chromatography on Sephadex G-50. The specific activity increased by 23 and 25 folds, respectively. These lectins from both the varieties were found to be specific for mannose. The purified fluorescein isothiocyanate (FITC)-labelled lectins showed binding reaction with homologous as well as heterologous strains of Rhizobium spp. The results revealed that pea lectins are not highly specific to their respective rhizobia. Moreover, these lectins showed a greater stimulatory effect on homologous Rhizobium leguminosarum strains.

  12. Characterization of a cytolytic strain of equine infectious anemia virus.

    Science.gov (United States)

    Maury, Wendy; Wright, Patrick J; Bradley, Sarahann

    2003-02-01

    A novel strain of equine infectious anemia virus (EIAV) called vMA-1c that rapidly and specifically killed infected equine fibroblasts (ED cells) but not other infectible cell lines was established. This strain was generated from an avirulent, noncytopathic strain of EIAV, MA-1. Studies with this new cytolytic strain of virus have permitted us to define viral parameters associated with EIAV-induced cell killing and begin to explore the mechanism. vMA-1c infection resulted in induction of rapid cell death, enhanced fusogenic activity, and increased rates of spread in equine fibroblasts compared to other strains of EIAV. The highly cytolytic nature of vMA-1c suggested that this strain might be superinfecting equine fibroblasts. Receptor interference studies demonstrated that prior infection of equine fibroblasts with EIAV did not alter the ability of vMA-1c to infect and kill these cells. In similar studies in a canine fibroblast cell line, receptor interference did occur. vMA-1c infection of equine fibroblasts was also associated with large quantities of unintegrated viral DNA, a well-established hallmark of retroviral superinfection. Cloning of the vMA-1c genome identified nucleotide changes that would result in at least one amino acid change in all viral proteins. A chimeric infectious molecular clone containing the vMA-1c tat, S2, and env open reading frames recapitulated most of the characteristics of vMA-1c, including superinfection, fibroblast killing, and fusogenic activity. In summary, in vitro selection for a strain of EIAV that rapidly killed cells resulted in the generation of a virus that was able to superinfect these cells, presumably by the use of a novel mechanism of cell entry. This phenotype mapped to the 3' half of the genome.

  13. Strain-based failure criteria for steel containments

    International Nuclear Information System (INIS)

    Fanous, F.; Greimann, L.F.

    1989-01-01

    The Containment Integrity Division of the Sandia National Laboratories (Sandia) has been conducting a program to evaluate the performance of containment buildings with internal pressure. Sandia has suggested that in the absence of leakage past penetrations, containment buildings will fail by rupturing after large plastic strains are developed up to ultimate strain of the material. This paper represents a portion of work conducted at Ames Laboratory for Sandia, the objective of which was to identify fabrication details that may affect the performance of a containment building. Construction drawings for nine steel containment buildings were surveyed, and several significant strain concentration regions were identified by using recommendations from Sandia and Section NE-3217 of the ASME Boiler and Pressure Vessel Code. These following regions were identified as: eccentricities in stiffener patterns around penetrations, eccentricities in containment shell middle surface, flat plate covers used on spare penetrations, containment base connection details, and containment heads. Examples of each of these regions were analyzed by the finite-element method, by simplified equations or both. In the case of middle surface eccentricities, the strains were found to be self-limiting. Even though flat plates have primary strains, they are typically designed so as not to control. Bolts in the base connection have primary strains and may control. The circumferential compressive strains introduced at the knuckle during buckling of the containment head grow as the pressure increases, but are somewhat restricted by the meridional tension. Finally, three analysis techniques and their associated failure criteria for the analysis of containment strength are introduced. (orig.)

  14. Intraspecific competition between co-infecting parasite strains enhances host survival in African trypanosomes.

    Science.gov (United States)

    Balmer, Oliver; Stearns, Stephen Curtis; Schötzau, Andreas; Brun, Reto

    2009-12-01

    It is becoming increasingly clear that under natural conditions parasitic infections commonly consist of co-infections with multiple conspecific strains. Multiple-strain infections lead to intraspecific interactions and may have important ecological and evolutionary effects on both hosts and parasites. However, experimental evidence on intraspecific competition or facilitation in infections has been scarce because of the technical challenges of distinguishing and tracking individual co-infecting strains. To overcome this limitation, we engineered transgenic strains of the protozoan parasite Trypanosoma brucei, the causal agent of human African sleeping sickness. Different strains were transfected with fluorescence genes of different colors to make them visually distinguishable in order to investigate the effects of multiple-strain infections on parasite population dynamics and host fitness. We infected mice either with each strain alone or with mixes of two strains. Our results show a strong mutual competitive suppression of co-infecting T. brucei strains very early in infection. This mutual suppression changes within-host parasite dynamics and alleviates the effects of infection on the host. The strength of suppression depends on the density of the co-infecting strain, and differences in life-history traits between the strains determine the consequences of strain-strain competition for the host. Unexpectedly, co-infection with a less virulent strain significantly enhances host survival (+15%). Analysis of the strain dynamics reveals that this is due to the suppression of the density of the more virulent strain (-33%), whose degree of impact ultimately determines the physical condition of the host. The competitive suppression is likely caused by allelopathic interference or by apparent competition mediated by strain-specific immune responses. These findings highlight the importance of intraspecific variation for parasite-parasite and parasite-host interactions. To

  15. Tensile behaviour of aluminium 7017 alloy at various temperatures and strain rates

    Directory of Open Access Journals (Sweden)

    Ravindranadh Bobbili

    2016-04-01

    Full Text Available The objective of the present study is to carry out high strain rate tensile tests on 7017 aluminium alloy under different strain rates ranging from 0.01, 500, 1000 and 1500 s−1 and at temperatures of 25, 100, 200 and 300 °C. Quasi-Static tensile stress–strain curves were generated using INSTRON 8500 machine. Johnson-Cook (J-C constitutive model was developed for 7017 aluminium alloy based on high strain rate tensile data generated from split Hopkinson tension bar (SHTB at various temperatures. This study evidently showed an improvement in dynamic strength as the strain rate increases. The predictions of J-C model are observed to be in consistence with the experimental data for all strain rates and temperatures. The fracture surfaces of specimens tested were studied under SEM. The change in fracture mode has been observed at different strain rates. The shear mode of fracture is dominant at lower strain rates (0.01 and 500 s−1; whereas cup- and cone-like surface representing dimple structure is found at the higher strain rates (1000 and 1500 s−1. The numbers of dimples at high strain rates are more than the quasi-static and intermediate strain rates. It is also observed that the flow stress decreases with increase in temperature. The 7017 aluminium alloy demonstrates thermal softening at higher temperatures. So when the temperature is more than 200 °C at these strain rates, thermal softening is predominant mode of deformation mechanism. It is found that when the temperature increases to 200 °C, the number of dimples rises and the dimple size of 7017 aluminium alloy is larger than at lower temperatures.

  16. Studies on Drosophila radiosensitivity strains

    International Nuclear Information System (INIS)

    Varentsova, E.R.; Sharygin, V.I.; Khromykh, Yu.U.

    1985-01-01

    Fertility of radiosensitive mutant drosophila female strain rad (2) 201 61 after irradiation and frequency of dominant lethal mutations (DLM), induced by γ-radiation for 0-5 h and 5-7 days, are investigated. It is shown, that oocytes of the mutant strain are more radiosensitive as compared with cells of mongrel flies as to criterion of DLM appearance over the period of maturing. Early oocytes of stages 2-7 are the most sensitive, i.e. at the stages, corresponding to the manifestation of previously established recombination-defective properties of mutations rad (2) 201 61 . It is also sown, that doses of γ-rays, exceeding 10 Gy produce a strong sterilizing effect on mutant females due to destruction and resorption of egg chambers, irradiated at the stages of previtellogenetic growth of oocytes. In females, carrying mutation of radiosensitivity there is no direct correlation betwen sensitivity of oocytes proper to DLM induction and sensitivity of egg folleicles to resorbing effect of γ-rays. The ways of possible involvement of mutant locus studied into genetic processes in various specialized cells of drosophila

  17. Strain rate dependence in plasticized and un-plasticized PVC

    Directory of Open Access Journals (Sweden)

    Siviour C.R.

    2012-08-01

    Full Text Available An experimental and analytical investigation has been made into the mechanical behaviour of two poly (vinyl chloride (PVC polymers – an un-plasticized PVC and a diisononyl phthalate (DINP-plasticized PVC. Measurements of the compressive stress-strain behaviour of the PVCs at strain rates ranging from 10−3 to 103s−1 and temperatures from − 60 to 100∘C are presented. Dynamic Mechanical Analysis was also performed in order to understand the material transitions observed in compression testing as the strain rate is increased. This investigation develops a better understanding of the interplay between the temperature dependence and rate dependence of polymers, with a focus on locating the temperature and rate-dependent material transitions that occur during high rate testing.

  18. Strain Elastography of Breast and Prostata Cancer: Similarities and Differences.

    Science.gov (United States)

    Daniaux, M; Auer, T; De Zordo, T; Junker, D; Santner, W; Hubalek, M; Jaschke, W; Aigner, F

    2016-03-01

    Typically both breast and prostate cancer present as tissue with decreased elasticity. Palpation is the oldest technique of tumor detection in both organs and is based on this principle. Thus an operator can grade a palpable mass as suspicious for cancer. Strain elastography as modern ultrasound technique allows the visualization of tissue elasticity in a color coded elastogram and can be understood as technical finger. The following article shows similarities and differences of ultrasound strain elastography in the diagnosis of breast and prostate cancer. • In prostata cancer elastography, in breast cancer B-mode is the primary sonographic search modality. • The diagnostic value of the search modalities change with increasing age.• A cut-off value for a strain ratio is hard to obtain in the elastography of the prostata, because there is no stabile reference tissue in the prostata. © Georg Thieme Verlag KG Stuttgart · New York.

  19. Distributed perfluorinated POF strain sensor using OTDR and OFDR techniques

    Science.gov (United States)

    Liehr, Sascha; Wendt, Mario; Krebber, Katerina

    2009-10-01

    This paper presents the latest advances in distributed strain sensing using perfluorinated (PF) polymer optical fibers (POF). Compared to previously introduced PMMA POF strain sensors, PF POF have the advantage of lower loss and therefore extended measurement length of more than 500 m at increased spatial resolution of 10 cm. It is shown that PF POF can measure strain distributed up to 100 %. The characteristic backscatter signature of this fiber type provides additional evaluation possibilities. We show that, by applying a cross-correlation algorithm to the backscatter signal, the distributed length change can be measured along the fiber. We also present, to our knowledge for the first time, incoherent Optical Frequency Domain Reflectometry (OFDR) in POF to measure distributed reflections and loss along the fiber. The OFDR technique proves superior to existing OTDR techniques in measurement speed, resolution and potential instrument costs.

  20. Sleep monitoring sensor using flexible metal strain gauge

    Science.gov (United States)

    Kwak, Yeon Hwa; Kim, Jinyong; Kim, Kunnyun

    2018-05-01

    This paper presents a sleep monitoring sensor based on a flexible metal strain gauge. As quality of life has improved, interest in sleep quality, and related products, has increased. In this study, unlike a conventional single sensor based on a piezoelectric material, a metal strain gauge-based array sensor based on polyimide and nickel chromium (NiCr) is applied to provide movement direction, respiration, and heartbeat data as well as contact-free use by the user during sleeping. Thin-film-type resistive strain gage sensors are fabricated through the conventional flexible printed circuit board (FPCB) process, which is very useful for commercialization. The measurement of movement direction and respiratory rate during sleep were evaluated, and the heart rate data were compared with concurrent electrocardiogram (ECG) data. An algorithm for analyzing sleep data was developed using MATLAB, and the error rate was 4.2% when compared with ECG for heart rate.

  1. Salt stress sensitivity of nitrogen fixation in Enterobacter agglomerans strains.

    Science.gov (United States)

    Rai, Raman; Rieder, Gabriele

    1998-12-01

    Two strains 333 to 339 of Enterobacter agglomerans were selected in the present study to evaluate the response of increasing concentrations of NaCl on growth, N(2)-fixation, and nitrogenase activity/synthesis. E. agglomerans strains 333 and 339 showed optimum growth and acetylene-reducing activity with 0.5 to 1.0% NaCl in a nitrogen-free minimal medium (NFDM) with glucose, respectively, in 28 h incubation, although both strains displayed better growth and acetylene-reducing activity with 3.0% and 2.0% NaCl after 52 h and 100 h incubation periods than the 28 h culture did. Our experiments with shiftings of salt concentrations in NFDM medium indicated that a synthesis of nitrogenase enzyme was generally more sensitive to higher concentrations of NaCl than nitrogenase activity was.

  2. Remote Strain Sensing of CFRP Using Microwave Frequency Domain Reflectometry

    Science.gov (United States)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    NASA's Advanced Composites Project is investigating technologies that increase automated remote inspection of aircraft composite structures. Therefore, microwave Frequency Domain Reflectometry (FDR) is being investigated as a method of enabling rapid remote measurement of strain occurring at the first ply of a composite fiber reinforced polymer (CFRP) structure using Radio Frequency (RF) Electro-Magnetic (EM) radiation. While microwave reflectometry has been used to detect disbonds in CFRP structures, its use in detecting strain has been limited. This work will present data demonstrating the measurement of the reactance changes due to loading conditions that are indicative of strain in a CFRP structure. In addition, the basic EM signature will be presented along with an analysis of temperature and humidity effects.

  3. Band-gap engineering in fluorographene nanoribbons under uniaxial strain

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan, E-mail: bingbing@mail.ustc.edu.cn, E-mail: liqun@ustc.edu.cn; Li, Qunxiang, E-mail: bingbing@mail.ustc.edu.cn, E-mail: liqun@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-01-28

    Based on extensive first-principles calculations, we report the structural and electronic properties of fluorinated graphene, i.e., fluorographene nanoribbons (FGNRs) under uniaxial strain. Our results indicate that the FGNRs are semiconductors with wide direct band gaps regardless of their edge structures. Moreover, the band gap of FGNR can be effectively modulated nonlinearly with the applied uniaxial elastic strain, where the band gap value increases first and then reduces when the applied strain changes from −10.0% to 10.0%. This abnormal behavior mainly originates from the electronic structures of valence and conduction band edges, which is quite different from previously reported linear behavior on graphene nanoribbon. Our results imply the great potential applications of FGNRs in the optical electronics.

  4. Anisotropic RKKY interaction and modulation with mechanical strain in phosphorene

    Science.gov (United States)

    Duan, Houjian; Li, Shuai; Zheng, Shi-Han; Sun, Zhenlong; Yang, Mou; Wang, Rui-Qiang

    2017-10-01

    We investigate the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between two magnetic impurities placed on a phosphorene surface based on the tight-binding model. It is found that the RKKY interaction exhibits strong anisotropy along different lattice directions and is sensitive to the deformed direction. The RKKY interaction is largest for impurities distributed in the armchair direction while the strain effect is strongest for the deformation exerted along the zigzag direction. Applied linear strain can increase the RKKY magnitude nonlinearly, and observably prolong the decay rate from the exponent to the 1/{R}2 law with the impurity distance. Most interestingly, near the strain-induced closing point of the bandgap, we find that the RKKY interaction is no longer simply ferromagnetic or antiferromagnetic, but presents oscillatory behavior, exhibiting the transition from ferromagnetism to antiferromagnetism. This originates from the combination effect of negative energy in the conduction band due to modification of the Fermi surface and the narrowing bandgap, and importantly both of them are reached simultaneously just by tuning the strain. Therefore, the strain effect proves to be an alternative approach to engineering impurity interactions in phosphorene materials.

  5. Room Temperature Dynamic Strain Aging in Ultrafine-Grained Titanium

    Science.gov (United States)

    Lopes, Felipe Perissé D.; Lu, Chia Hui; Zhao, Shiteng; Monteiro, Sergio N.; Meyers, Marc A.

    2015-10-01

    Dynamic strain aging (DSA) in coarse-grained (CG) titanium is usually observed at intermediate to high temperatures 473 K to 973 K (200 °C to 700 °C) and is characterized by serrations in the stress vs strain curves. In the present work, despite the absence of apparent serrations, ultrafine-grained titanium (UFG Ti) undergoes DSA at room temperature, exhibited through an abnormal increase in the elastic limit and negative strain rate sensitivity. This effect is observed at 293 K (20 °C) in the strain rate interval of 10-4 to 10-2 s-1, and at 203 K (-70 °C) and 373 K (100 °C) in a distinct strain rate range. Based on a calculated activation energy of 17.3 kJ/mol and microstructural observations by transmission electron microscopy, it is proposed that the dominant mechanism for DSA in UFG Ti involves interstitial solutes interacting with dislocations emitted from grain boundaries. The interstitials migrate from the grain boundaries along dislocation lines bowing out as they are emitted from the boundaries, a mechanism with a low calculated activation energy which is comparable with the experimental measurements. The dislocation velocities and interstitial diffusion along the dislocation cores are consistent.

  6. Observations of Dynamic Strain Aging in Polycrystalline NiAl

    Science.gov (United States)

    Weaver, M. L.; Noebe, R. D.; Kaufman, M. J.

    1996-01-01

    Dynamic strain aging has been investigated at temperatures between 77 and 1100 K in eight polycrystalline NiAl alloys. The 0.2% offset yield stress and work hardening rates for these alloys generally decreased with increasing temperature. However, local plateaus or maxima were observed in conventional purity and carbon doped alloys at intermediate temperatures (600-900 K). This anomalous behavior was not observed in low interstitial high-purity, nitrogen doped, or in titanium doped materials. Low or negative strain rate sensitivities (SRS) were also observed in all eight alloys in this intermediate temperature range. Coincident with the occurrence of negative SRS was the occurrence of serrated flow in conventional purity alloys containing high concentrations of Si in addition to C. These phenomena have been attributed to dynamic strain aging (DSA). Chemical analysis of the alloys used in this study suggests that the main species causing strain aging in polycrystalline NiAl is C but indicate that residual Si impurities can enhance the strain aging effect.

  7. Time-dependent strains and stresses in a pumpkin balloon

    Science.gov (United States)

    Gerngross, T.; Xu, Y.; Pellegrino, S.

    This paper presents a study of pumpkin-shaped superpressure balloons consisting of gores made from a thin polymeric film attached to high stiffness meridional tendons This type of design is being used for the NASA ULDB balloons The gore film shows considerable time-dependent stress relaxation whereas the behaviour of the tendons is essentially time-independent Upon inflation and pressurization the instantaneous i e linear-elastic strain and stress distributions in the film show significantly higher values in the meridional direction However over time and due to the biaxial visco-elastic stress relaxation of the the gore material the em hoop strains increase and the em meridional stresses decrease whereas the em remaining strain and stress components remain substantially unchanged These results are important for a correct assessment of the structural integrity of a pumpkin balloon in a long-duration mission both in terms of the material performance and the overall stability of the shape of the balloon An experimental investigation of the time dependence of the biaxial strain distribution in the film of a 4 m diameter 48 gore pumpkin balloon is presented The inflated shape of selected gores has been measured using photogrammetry and the time variation in strain components at some particular points of these gores has been measured under constant pressure and temperature The results show good correlation with a numerical study using the ABAQUS finite-element package that includes a widely used model of

  8. Strain Effect on Electronic Structure and Work Function in α-Fe2O3 Films

    Directory of Open Access Journals (Sweden)

    Li Chen

    2017-03-01

    Full Text Available We investigate the electronic structure and work function modulation of α-Fe2O3 films by strain based on the density functional method. We find that the band gap of clean α-Fe2O3 films is a function of the strain and is influenced significantly by the element termination on the surface. The px and py orbitals keep close to Fermi level and account for a pronounced narrowing band gap under compressive strain, while unoccupied dz2 orbitals from conduction band minimum draw nearer to Fermi level and are responsible for the pronounced narrowing band gap under tensile strain. The spin polarized surface state, arising from localized dangling-bond states, is insensitive to strain, while the bulk band, especially for pz orbital, arising from extended Bloch states, is very sensitive to strain, which plays an important role for work function decreasing (increasing under compressive (tensile strain in Fe termination films. In particular, the work function in O terminated films is insensitive to strain because pz orbitals are less sensitive to strain than that of Fe termination films. Our findings confirm that the strain is an effective means to manipulate electronic structures and corrosion potential.

  9. Effect of CuO Nanoparticles over Isolated Bacterial Strains from Agricultural Soil

    International Nuclear Information System (INIS)

    Concha-Guerrero, S.I.; Pinon-Castillo, H.A.; Luna-Velasco, A.; Orrantia-Borunda, E.; Brito, E.M.S.; Tarango-Rivero, S.H.; Caretta, C.A.; Duran, R.

    2014-01-01

    The increased use of the nanoparticles (NPs) on several processes is notorious. In contrast the eco toxicological effects of NPs have been scarcely studied. The main current researches are related to the oxide metallic NPs. In the present work, fifty-six bacterial strains were isolated from soil, comprising 17 different OTUs distributed into 3 classes: Bacilli (36 strains), Flavobacteria (2 strains), and Gamma proteobacteria (18 strains). Copper oxide nanoparticles (CuONPs) were synthesized using a process of chemical precipitation. The obtained CuONPs have a spherical shape and primary size less than 17 nm. Twenty-one strains were used to evaluate the cytotoxicity of CuONPs and 11 of these strains showed high sensibility. Among those 11 strains, 4 (Brevibacillus later osporus strain CSS8, Chryseobacterium indoltheticum strain CSA28, and Pantoea ananatis strains CSA34 and CSA35) were selected to determine the kind of damage produced. The CuONPs toxic effect was observed at expositions over 25 mg·L -1 and the damage to cell membrane above 160 mg·L -1 . The electron microscopy showed the formation of cavities, holes, membrane degradation, blebs, cellular collapse, and lysis. These toxic effects may probably be due to the ions interaction, the oxide-reduction reactions, and the generation of reactive species

  10. Ultrasensitive tunability of the direct bandgap of 2D InSe flakes via strain engineering

    Science.gov (United States)

    Li, Yang; Wang, Tianmeng; Wu, Meng; Cao, Ting; Chen, Yanwen; Sankar, Raman; Ulaganathan, Rajesh K.; Chou, Fangcheng; Wetzel, Christian; Xu, Cheng-Yan; Louie, Steven G.; Shi, Su-Fei

    2018-04-01

    InSe, a member of the layered materials family, is a superior electronic and optical material which retains a direct bandgap feature from the bulk to atomically thin few-layers and high electronic mobility down to a single layer limit. We, for the first time, exploit strain to drastically modify the bandgap of two-dimensional (2D) InSe nanoflakes. We demonstrated that we could decrease the bandgap of a few-layer InSe flake by 160 meV through applying an in-plane uniaxial tensile strain to 1.06% and increase the bandgap by 79 meV through applying an in-plane uniaxial compressive strain to 0.62%, as evidenced by photoluminescence (PL) spectroscopy. The large reversible bandgap change of ~239 meV arises from a large bandgap change rate (bandgap strain coefficient) of few-layer InSe in response to strain, ~154 meV/% for uniaxial tensile strain and ~140 meV/% for uniaxial compressive strain, representing the most pronounced uniaxial strain-induced bandgap strain coefficient experimentally reported in 2D materials. We developed a theoretical understanding of the strain-induced bandgap change through first-principles DFT and GW calculations. We also confirmed the bandgap change by photoconductivity measurements using excitation light with different photon energies. The highly tunable bandgap of InSe in the infrared regime should enable a wide range of applications, including electro-mechanical, piezoelectric and optoelectronic devices.

  11. Enhanced ethanol fermentation by engineered Saccharomyces cerevisiae strains with high spermidine contents.

    Science.gov (United States)

    Kim, Sun-Ki; Jo, Jung-Hyun; Jin, Yong-Su; Seo, Jin-Ho

    2017-05-01

    Construction of robust and efficient yeast strains is a prerequisite for commercializing a biofuel production process. We have demonstrated that high intracellular spermidine (SPD) contents in Saccharomyces cerevisiae can lead to improved tolerance against various fermentation inhibitors, including furan derivatives and acetic acid. In this study, we examined the potential applicability of the S. cerevisiae strains with high SPD contents under two cases of ethanol fermentation: glucose fermentation in repeated-batch fermentations and xylose fermentation in the presence of fermentation inhibitors. During the sixteen times of repeated-batch fermentations using glucose as a sole carbon source, the S. cerevisiae strains with high SPD contents maintained higher cell viability and ethanol productivities than a control strain with lower SPD contents. Specifically, at the sixteenth fermentation, the ethanol productivity of a S. cerevisiae strain with twofold higher SPD content was 31% higher than that of the control strain. When the SPD content was elevated in an engineered S. cerevisiae capable of fermenting xylose, the resulting S. cerevisiae strain exhibited much 40-50% higher ethanol productivities than the control strain during the fermentations of synthetic hydrolysate containing high concentrations of fermentation inhibitors. These results suggest that the strain engineering strategy to increase SPD content is broadly applicable for engineering yeast strains for robust and efficient production of ethanol.

  12. Foil Strain Gauges Using Piezoresistive Carbon Nanotube Yarn: Fabrication and Calibration.

    Science.gov (United States)

    Abot, Jandro L; Góngora-Rubio, Mário R; Anike, Jude C; Kiyono, César Y; Mello, Luis A M; Cardoso, Valtemar F; Rosa, Reinaldo L S; Kuebler, Derek A; Brodeur, Grace E; Alotaibi, Amani H; Coene, Marisa P; Coene, Lauren M; Jean, Elizabeth; Santiago, Rafael C; Oliveira, Francisco H A; Rangel, Ricardo; Thomas, Gilles P; Belay, Kalayu; da Silva, Luciana W; Moura, Rafael T; Seabra, Antonio C; Silva, Emílio C N

    2018-02-05

    Carbon nanotube yarns are micron-scale fibers comprised by tens of thousands of carbon nanotubes in their cross section and exhibiting piezoresistive characteristics that can be tapped to sense strain. This paper presents the details of novel foil strain gauge sensor configurations comprising carbon nanotube yarn as the piezoresistive sensing element. The foil strain gauge sensors are designed using the results of parametric studies that maximize the sensitivity of the sensors to mechanical loading. The fabrication details of the strain gauge sensors that exhibit the highest sensitivity, based on the modeling results, are described including the materials and procedures used in the first prototypes. Details of the calibration of the foil strain gauge sensors are also provided and discussed in the context of their electromechanical characterization when bonded to metallic specimens. This characterization included studying their response under monotonic and cyclic mechanical loading. It was shown that these foil strain gauge sensors comprising carbon nanotube yarn are sensitive enough to capture strain and can replicate the loading and unloading cycles. It was also observed that the loading rate affects their piezoresistive response and that the gauge factors were all above one order of magnitude higher than those of typical metallic foil strain gauges. Based on these calibration results on the initial sensor configurations, new foil strain gauge configurations will be designed and fabricated, to increase the strain gauge factors even more.

  13. Foil Strain Gauges Using Piezoresistive Carbon Nanotube Yarn: Fabrication and Calibration

    Directory of Open Access Journals (Sweden)

    Jandro L. Abot

    2018-02-01

    Full Text Available Carbon nanotube yarns are micron-scale fibers comprised by tens of thousands of carbon nanotubes in their cross section and exhibiting piezoresistive characteristics that can be tapped to sense strain. This paper presents the details of novel foil strain gauge sensor configurations comprising carbon nanotube yarn as the piezoresistive sensing element. The foil strain gauge sensors are designed using the results of parametric studies that maximize the sensitivity of the sensors to mechanical loading. The fabrication details of the strain gauge sensors that exhibit the highest sensitivity, based on the modeling results, are described including the materials and procedures used in the first prototypes. Details of the calibration of the foil strain gauge sensors are also provided and discussed in the context of their electromechanical characterization when bonded to metallic specimens. This characterization included studying their response under monotonic and cyclic mechanical loading. It was shown that these foil strain gauge sensors comprising carbon nanotube yarn are sensitive enough to capture strain and can replicate the loading and unloading cycles. It was also observed that the loading rate affects their piezoresistive response and that the gauge factors were all above one order of magnitude higher than those of typical metallic foil strain gauges. Based on these calibration results on the initial sensor configurations, new foil strain gauge configurations will be designed and fabricated, to increase the strain gauge factors even more.

  14. Foil Strain Gauges Using Piezoresistive Carbon Nanotube Yarn: Fabrication and Calibration

    Science.gov (United States)

    Góngora-Rubio, Mário R.; Kiyono, César Y.; Mello, Luis A. M.; Cardoso, Valtemar F.; Rosa, Reinaldo L. S.; Kuebler, Derek A.; Brodeur, Grace E.; Alotaibi, Amani H.; Coene, Marisa P.; Coene, Lauren M.; Jean, Elizabeth; Santiago, Rafael C.; Oliveira, Francisco H. A.; Rangel, Ricardo; Thomas, Gilles P.; Belay, Kalayu; da Silva, Luciana W.; Moura, Rafael T.; Seabra, Antonio C.; Silva, Emílio C. N.

    2018-01-01

    Carbon nanotube yarns are micron-scale fibers comprised by tens of thousands of carbon nanotubes in their cross section and exhibiting piezoresistive characteristics that can be tapped to sense strain. This paper presents the details of novel foil strain gauge sensor configurations comprising carbon nanotube yarn as the piezoresistive sensing element. The foil strain gauge sensors are designed using the results of parametric studies that maximize the sensitivity of the sensors to mechanical loading. The fabrication details of the strain gauge sensors that exhibit the highest sensitivity, based on the modeling results, are described including the materials and procedures used in the first prototypes. Details of the calibration of the foil strain gauge sensors are also provided and discussed in the context of their electromechanical characterization when bonded to metallic specimens. This characterization included studying their response under monotonic and cyclic mechanical loading. It was shown that these foil strain gauge sensors comprising carbon nanotube yarn are sensitive enough to capture strain and can replicate the loading and unloading cycles. It was also observed that the loading rate affects their piezoresistive response and that the gauge factors were all above one order of magnitude higher than those of typical metallic foil strain gauges. Based on these calibration results on the initial sensor configurations, new foil strain gauge configurations will be designed and fabricated, to increase the strain gauge factors even more. PMID:29401745

  15. Non-uniformity of hot plastic strain of stainless steels with austenitic-ferritic structure

    International Nuclear Information System (INIS)

    Laricheva, L.P.; Peretyat'ko, V.N.; Rostovtsev, A.N.; Levius, A.M.

    1987-01-01

    Non-uniformity of hot strain of stainless steels of various alloying was investigated. Steels with austenite and δ-ferrite structure of two classes were chosen for investigation: 08Kh18N10T steel of austenitic class and 08Kh21N5T steel of austenitic-ferritic class. Tests were conducted for samples subjected to preliminary thermal treatment: heating up to 1250 deg C, holding during 0.5 h, cooling in water. The heat treatment enabled to produce large grains of austenite and δ-ferrite (about 30 μm) in 08Kh21N5T steel, and sufficient amount of δ-ferrite (up to 50%) in 08Kh18N10T steel. It is shown that hot strain of austenitic-ferritic steels is non-uniform. δ-ferrite strain is more pronounced as compared to austenite. The ratio of mean δ-ferrite strain to the mean austenite strain grows with increase of the degree of general steel strain and temperature. The ratio of mean phase strains in 08Kh18N10T steel is higher as compared to 08Kh21N5T steel, general strain and temperature being equal. Temperature effect on the ratio of δ-ferrite and austenite strains is more pronounced for 08Kh18N10T steel. It is explaind by the value of ratios of phase strain resistance and temperature effect on them

  16. Strain Effect on Electronic Structure and Work Function in α-Fe₂O₃ Films.

    Science.gov (United States)

    Chen, Li; Shi, Changmin; Li, Xiaolong; Mi, Zhishan; Wang, Dongchao; Liu, Hongmei; Qiao, Lijie

    2017-03-09

    We investigate the electronic structure and work function modulation of α-Fe₂O₃ films by strain based on the density functional method. We find that the band gap of clean α-Fe₂O₃ films is a function of the strain and is influenced significantly by the element termination on the surface. The p x and p y orbitals keep close to Fermi level and account for a pronounced narrowing band gap under compressive strain, while unoccupied d z ₂ orbitals from conduction band minimum draw nearer to Fermi level and are responsible for the pronounced narrowing band gap under tensile strain. The spin polarized surface state, arising from localized dangling-bond states, is insensitive to strain, while the bulk band, especially for p z orbital, arising from extended Bloch states, is very sensitive to strain, which plays an important role for work function decreasing (increasing) under compressive (tensile) strain in Fe termination films. In particular, the work function in O terminated films is insensitive to strain because p z orbitals are less sensitive to strain than that of Fe termination films. Our findings confirm that the strain is an effective means to manipulate electronic structures and corrosion potential.

  17. Genetically-Improved Tilapia Strains in Africa: Potential Benefits and Negative Impacts

    Directory of Open Access Journals (Sweden)

    Yaw B. Ansah

    2014-06-01

    Full Text Available Two genetically improved tilapia strains (GIFT and Akosombo have been created with Oreochromis niloticus (Nile tilapia, which is native to Africa. In particular, GIFT has been shown to be significantly superior to local African tilapia strains in terms of growth rate. While development economists see the potential for food security and poverty reduction in Africa from culture of these new strains of tilapia, conservationists are wary of potential ecological and genetic impacts on receiving ecosystems and native stocks of tilapia. This study reviews the history of the GIFT technology, and identifies potential environmental and genetic risks of improved and farmed strains and tilapia in general. We also estimate the potential economic gains from the introduction of genetically improved strains in Africa, using Ghana as a case country. Employing a combination of the Economic-Surplus model and Monte Carlo simulation, we found the mean net present value (NPV of the introduction of the GIFT strain in Ghana to be approximately 1% of the country’s gross domestic product. Sensitivity analysis indicated that the difference in growth or yield between the GIFT and locally-available strains has the largest effect on mean NPV. We conclude that improvements in management practices and infrastructure could increase the yield and profitability of the local strains even if genetically-improved strains are not introduced. These improvements also will ensure the realization of the full potential of introduced strains.

  18. Yeast strains designed for 2. generation bioethanol production. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Roennow, B.

    2013-04-15

    The aim of the project was to develop a suitable fermentation organism for 2G bioethanol production that would efficiently ferment all of the sugars in lignocellulosic biomass into ethanol at a commercially viable rate (comparable to yeast based 1G ethanol production). More specifically, a yeast strain would be developed with the ability to ferment also the pentoses in lignocellulosic biomass and thereby increase the ethanol yield of the process by 30-45% with a profound positive effect on the total process economy. The project has succeeded in developing a new industrial yeast strain V1. The yeast strain can transform the difficult C5 sugars to ethanol from waste products such as straw and the like from the agricultural sector. The classic issues relating to industrial uses such as inhibitor and ethanol tolerance and high ethanol production is resolved satisfactorily. The potential of the use of the new strain for 2nd generation bioethanol production is that the ethanol yields increase by 30-45%. With the increased ethanol yield follows a marked improvement in the overall process economics. (LN)

  19. DOMESTIC BUTANOL-PRODUCING STRAINS OF THE Clostridium GENUS

    Directory of Open Access Journals (Sweden)

    O. O. Tigunova

    2017-02-01

    Full Text Available The aim of the work was to summarize the results of own research concerning obtaining butanol producing strains of Clostridium genus, to identify them by physiological, morphological and genetic methods. Further study of characteristics and biological features of the strains, and various approaches in biotechnological process of butanol production are discussed. The work includes methods to increase butanol accumulation by producer strains. Perspectives of using chemical mutagenesis in Clostridia as a method of increasing butanol production are considered. The feasibility of using non-food raw material as a substrate for fermentation is discussed. Different methods of pretreatment and their impact on the accumulation of butanol in the liquid medium are compared. Butanol accumulation is shown to increase significantly if the synthesis precursors are added as components of enzymatic medium, and the “reverse bard” is used to reduce waste production without affecting the level of butanol synthesis. The problem of conservation of producing strains is given, and protective medium for microorganisms during the freeze-drying is defined.

  20. Determination of strain localization in aluminum alloys using photoemission measurements

    Science.gov (United States)

    Cai, Mingdong; Langford, Stephen; Levine, Lyle; Dickinson, Thomas

    2004-03-01

    We report photoemission measurements during uniaxial tensile deformation of aluminum (1200), Al-Mn (3003), Al-Mg (5052), and Al-Mg-Si (6061) alloys during exposure to pulsed excimer laser radiation (248-nm). Photostimulated electron emission increases with strain as slip exposes fresh metal to the vacuum; strain localization alters the production rate of slip bands and hence can be monitored by this technique. All samples were annealed at 300 °C for three hours immediately after polishing to produce a relatively thick (typically 40-nm) surface oxide. This oxide reduces photoemission from undeformed material. Time-resolved electron emission measurements after each laser pulse show two or more photoemission peaks. The intensity of the late (slow) peaks changes little during deformation and apparently reflects electron emission from oxidized, undeformed portions of the sample and other nearby surfaces. The intensity of the first (fast) electron peak reflects emission from fresh metal along slip lines/bands generated by deformation. As strain proceeds, the intensity of the fast peak shows three stages of growth: a gradually increasing, incipient growth during the onset of deformation, followed by two linear increasing stages. We provide evidence that the transition between the two linear stages corresponds to the onset of strain localization.

  1. Demonstration of bacteriocin activity in bovine and bison strains of Pasteurella multocida. [UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chengappa, M.M.; Carter, G.R.

    1977-08-01

    Of 33 strains of Pasteurella multocida examined, 14 showed bacteriocin activity and 17 were susceptible to bacteriocin. The activity was increased by about twofold if the cultures were induced with ultraviolet radiation; however, no increase in bacteriocin activity was observed if the potential producer strains were induced with mitomycin C. The bacteriocin activity of potential producer strains was increased if CaCl/sub 2/ was incorporated in the medium. The patterns of bacteriocin susceptibility indicate that these substances may ultimately contribute to a typing scheme for the species. An extra-chromosomal genetic element was not detected when a potential producer strain was not detected when a potential producer strain was tested by the dye-buoyant density gradient method. This fact suggests that the genetic material responsible for bacteriocin activity in P multocida is located on the host chromosome proper.

  2. SPICE compatible analytical electron mobility model for biaxial strained-Si-MOSFETs

    International Nuclear Information System (INIS)

    Chaudhry, Amit; Sangwan, S.; Roy, J. N.

    2011-01-01

    This paper describes an analytical model for bulk electron mobility in strained-Si layers as a function of strain. Phonon scattering, columbic scattering and surface roughness scattering are included to analyze the full mobility model. Analytical explicit calculations of all of the parameters to accurately estimate the electron mobility have been made. The results predict an increase in the electron mobility with the application of biaxial strain as also predicted from the basic theory of strain physics of metal oxide semiconductor (MOS) devices. The results have also been compared with numerically reported results and show good agreement. (semiconductor devices)

  3. Strain-rate dependent fatigue behavior of 316LN stainless steel in high-temperature water

    Science.gov (United States)

    Tan, Jibo; Wu, Xinqiang; Han, En-Hou; Ke, Wei; Wang, Xiang; Sun, Haitao

    2017-06-01

    Low cycle fatigue behavior of forged 316LN stainless steel was investigated in high-temperature water. It was found that the fatigue life of 316LN stainless steel decreased with decreasing strain rate from 0.4 to 0.004 %s-1 in 300 °C water. The stress amplitude increased with decreasing strain rate during fatigue tests, which was a typical characteristic of dynamic strain aging. The fatigue cracks mainly initiated at pits and slip bands. The interactive effect between dynamic strain aging and electrochemical factors on fatigue crack initiation is discussed.

  4. Context and strain-dependent behavioral response to stress

    Directory of Open Access Journals (Sweden)

    Baum Amber E

    2008-06-01

    Full Text Available Abstract Background This study posed the question whether strain differences in stress-reactivity lead to differential behavioral responses in two different tests of anxiety. Strain differences in anxiety-measures are known, but strain differences in the behavioral responses to acute prior stress are not well characterized. Methods We studied male Fisher 344 (F344 and Wistar Kyoto (WKY rats basally and immediately after one hour restraint stress. To distinguish between the effects of novelty and prior stress, we also investigated behavior after repeated exposure to the test chamber. Two behavioral tests were explored; the elevated plus maze (EPM and the open field (OFT, both of which are thought to measure activity, exploration and anxiety-like behaviors. Additionally, rearing, a voluntary behavior, and grooming, a relatively automatic, stress-responsive stereotyped behavior were measured in both tests. Results Prior exposure to the test environment increased anxiety-related measures regardless of prior stress, reflecting context-dependent learning process in both tests and strains. Activity decreased in response to repeated testing in both tests and both strains, but prior stress decreased activity only in the OFT which was reversed by repeated testing. Prior stress decreased anxiety-related measures in the EPM, only in F344s, while in the OFT, stress led to increased freezing mainly in WKYs. Conclusion Data suggest that differences in stressfulness of these tests predict the behavior of the two strains of animals according to their stress-reactivity and coping style, but that repeated testing can overcome some of these differences.

  5. Physical Strain: A New Perspective on Walking in Cerebral Palsy.

    Science.gov (United States)

    Balemans, Astrid C; Bolster, Eline A; Brehm, Merel-Anne; Dallmeijer, Annet J

    2017-12-01