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Sample records for marcescens polyribosome fractions

  1. Polyribosomes from Pear Fruit: Changes during Ripening and Senescence.

    Science.gov (United States)

    Drouet, A; Hartmann, C

    1979-12-01

    Polysome profiles were examined from lyophilized peel tissue of ripening pear (Pyrus communis, L. var. Passe-Crassane). Messenger RNA chains bearing up to eight ribosomes (octamers) were resolved and exhibited the highest absorption peak when ribonuclease activity was eliminated during extraction. Neither normal ripening nor the increase of large polyribosomes that normally accompanies ripening and senescence of the fruit occurred when pretreatment at 0 C was omitted. Normal ripening and increase of large polyribosomes would, however, be initiated by an ethylene treatment. The size distribution of the polyribosomes remained essentially constant throughout a 4-month cold storage; there was, however, a large increase in ribosomes by the 12th week of storage.

  2. [Efflux systems in Serratia marcescens].

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    Mardanova, A M; Bogomol'naia, L M; Romanova, Iu D; Sharipova, M R

    2014-01-01

    A widespread bacterium Serratia marcescens (family Enterobacteriaceae) is an opportunistic and exhibits multiple drug resistance. Active removal of antibiotics and other antimicrobials from pathogen and exhibits multiple drug resistance. Active removal of antibiotics and other antimicrobials from the cells by efflux systems is one of the mechanisms responsible for microbial resistance to these compounds. Among enterobacteria, efflux systems of Escherichia coli and Salmonella enterica var. Typhimurium have been studied most extensively. Few efflux systems that belong to different families have been reported for S. marcescens. In this review, we analyzed available literature about S. marcescens efflux systems and carried out the comparative analysis of the genes encoding the RND type systems in different Serratia species and in other enterobacteria. Bioinformatical analysis of the S. marcescens genome allowed us to identify the previously unknown efflux systems based on their homology with the relevant E. coli genes. Identification of additional efflux systems in S. marcescens genome will promote our understanding of physiology of these bacteria, will detect new molecular mechanisms of resistance and will reveal their resistance potential.

  3. Sepse por Serratia marcescens KPC Serratia marcescens KPC sepsis

    OpenAIRE

    Pedro Fernandez Del Peloso; Matheus Felipe Leal de Barros; Fernanda Abreu dos Santos

    2010-01-01

    A resistência aos carbapenems entre as bactérias não fermentadoras de glicose é comumente descrita. Porém, os relatos de resistência aos carbapenems em enterobactérias ainda são fatos isolados. Neste relato de caso, descrevemos um caso de infecção generalizada por Serratia marcescens carreadora de gene blaKPC. No Brasil, já foram relatados casos de isolados de Klebsiella pneumoniae e Escherichia coli carreando gene blaKPC, ficando evidente a emergência desse tipo de carbapenemase e sua dissem...

  4. Sepse por Serratia marcescens KPC Serratia marcescens KPC sepsis

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    Pedro Fernandez Del Peloso

    2010-10-01

    Full Text Available A resistência aos carbapenems entre as bactérias não fermentadoras de glicose é comumente descrita. Porém, os relatos de resistência aos carbapenems em enterobactérias ainda são fatos isolados. Neste relato de caso, descrevemos um caso de infecção generalizada por Serratia marcescens carreadora de gene blaKPC. No Brasil, já foram relatados casos de isolados de Klebsiella pneumoniae e Escherichia coli carreando gene blaKPC, ficando evidente a emergência desse tipo de carbapenemase e sua disseminação entre espécies diferentes de enterobactérias em nosso país.Carbapenem resistance among Gram-negative non fermentative bacteria is widely known, whereas carbapenem resistance among Enterobacteriaceae is rare. In this study we describe a case of sepsis caused by Serratia marcescens carrying blaKPC gene. In Brazil, cases of KPC have been reported in Klebsiella pneumoniae and Escherichia coli, which shows the emergence of this kind of carbapenemase and its dissemination among different species of Enterobacteriaceae in our country.

  5. Sepse por Serratia marcescens KPC

    OpenAIRE

    Del Peloso, Pedro Fernandez; Barros,Matheus Felipe Leal de; Santos,Fernanda Abreu dos

    2010-01-01

    A resistência aos carbapenems entre as bactérias não fermentadoras de glicose é comumente descrita. Porém, os relatos de resistência aos carbapenems em enterobactérias ainda são fatos isolados. Neste relato de caso, descrevemos um caso de infecção generalizada por Serratia marcescens carreadora de gene blaKPC. No Brasil, já foram relatados casos de isolados de Klebsiella pneumoniae e Escherichia coli carreando gene blaKPC, ficando evidente a emergência desse tipo de carbapenemase e sua dissem...

  6. Review of Prodigiosin, Pigmentation in Serratia marcescens

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    Anita Khanafari

    2006-01-01

    Full Text Available Prodigiosins, a family of natural red pigments characterized by a common pyrrolylpyrromethane skeleton, are produced by various bacteria that first characterized from Serratia marcescens. This pigment is a promising drug owing to its reported characteristics of having antifungal, immunosuppressive and anti-proliferative activity. From an industrial point of view to obtain optimal conditions to enhance the growth of Serratia marcescens and the pigment production is necessity. In present study, the production condition, physicochemical and functional characteristics, structure, genetic and gene expression, apoptosis and toxigenic effects of prodigiosin will be discussed in-order to contribute to the world of Serratia marcescens with respect to its prodigiosin production property.

  7. Biological activity of Serratia marcescens cytotoxin

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    G.V. Carbonell

    2003-03-01

    Full Text Available Serratia marcescens cytotoxin was purified to homogeneity by ion-exchange chromatography on a DEAE Sepharose Fast Flow column, followed by gel filtration chromatography on a Sephadex G100 column. The molecular mass of the cytotoxin was estimated to be about 50 kDa. Some biological properties of the cytotoxin were analyzed and compared with well-characterized toxins, such as VT1, VT2 and CNF from Escherichia coli and hemolysin produced by S. marcescens. The sensitivity of the cell lines CHO, HeLa, HEp-2, Vero, BHK-21, MA 104 and J774 to the cytotoxin was determined by the cell viability assay using neutral red. CHO and HEp-2 were highly sensitive, with massive cellular death after 1 h of treatment, followed by BHK-21, HeLa, Vero and J774 cells, while MA 104 was insensitive to the toxin. Cytotoxin induced morphological changes such as cell rounding with cytoplasmic retraction and nuclear compactation which were evident 15 min after the addition of cytotoxin. The cytotoxic assays show that 15 min of treatment with the cytotoxin induced irreversible intoxication of the cells, determined by loss of cell viability. Concentrations of 2 CD50 (0.56 µg/ml of purified cytotoxin did not present any hemolytic activity, showing that the cytotoxin is distinct from S. marcescens hemolysin. Antisera prepared against S. marcescens cytotoxin did not neutralize the cytotoxic activity of VT1, VT2 or CNF toxin, indicating that these toxins do not share antigenic determinants with cytotoxin. Moreover, we did not detect gene sequences for any of these toxins in S. marcescens by PCR assay. These results suggest that S. marcescens cytotoxin is not related to any of these toxins from E. coli.

  8. Biological activity of Serratia marcescens cytotoxin.

    Science.gov (United States)

    Carbonell, G V; Amorim, C R N; Furumura, M T; Darini, A L C; Fonseca, B A L; Yano, T

    2003-03-01

    Serratia marcescens cytotoxin was purified to homogeneity by ion-exchange chromatography on a DEAE Sepharose Fast Flow column, followed by gel filtration chromatography on a Sephadex G100 column. The molecular mass of the cytotoxin was estimated to be about 50 kDa. Some biological properties of the cytotoxin were analyzed and compared with well-characterized toxins, such as VT1, VT2 and CNF from Escherichia coli and hemolysin produced by S. marcescens. The sensitivity of the cell lines CHO, HeLa, HEp-2, Vero, BHK-21, MA 104 and J774 to the cytotoxin was determined by the cell viability assay using neutral red. CHO and HEp-2 were highly sensitive, with massive cellular death after 1 h of treatment, followed by BHK-21, HeLa, Vero and J774 cells, while MA 104 was insensitive to the toxin. Cytotoxin induced morphological changes such as cell rounding with cytoplasmic retraction and nuclear compactation which were evident 15 min after the addition of cytotoxin. The cytotoxic assays show that 15 min of treatment with the cytotoxin induced irreversible intoxication of the cells, determined by loss of cell viability. Concentrations of 2 CD50 (0.56 g/ml) of purified cytotoxin did not present any hemolytic activity, showing that the cytotoxin is distinct from S. marcescens hemolysin. Antisera prepared against S. marcescens cytotoxin did not neutralize the cytotoxic activity of VT1, VT2 or CNF toxin, indicating that these toxins do not share antigenic determinants with cytotoxin. Moreover, we did not detect gene sequences for any of these toxins in S. marcescens by PCR assay. These results suggest that S. marcescens cytotoxin is not related to any of these toxins from E. coli.

  9. The molecular structure of the left-handed supra-molecular helix of eukaryotic polyribosomes.

    Science.gov (United States)

    Myasnikov, Alexander G; Afonina, Zhanna A; Ménétret, Jean-François; Shirokov, Vladimir A; Spirin, Alexander S; Klaholz, Bruno P

    2014-11-07

    During protein synthesis, several ribosomes bind to a single messenger RNA (mRNA) forming large macromolecular assemblies called polyribosomes. Here we report the detailed molecular structure of a 100 MDa eukaryotic poly-ribosome complex derived from cryo electron tomography, sub-tomogram averaging and pseudo-atomic modelling by crystal structure fitting. The structure allowed the visualization of the three functional parts of the polysome assembly, the central core region that forms a rather compact left-handed supra-molecular helix, and the more open regions that harbour the initiation and termination sites at either ends. The helical region forms a continuous mRNA channel where the mRNA strand bridges neighbouring exit and entry sites of the ribosomes and prevents mRNA looping between ribosomes. This structure provides unprecedented insights into protein- and RNA-mediated inter-ribosome contacts that involve conserved sites through 40S subunits and long protruding RNA expansion segments, suggesting a role in stabilizing the overall polyribosomal assembly.

  10. Intracranial complications of Serratia marcescens infection in neonates.

    Science.gov (United States)

    Madide, Ayanda; Smith, Johan

    2016-03-15

    Even though Serratia marcescens is not one of the most common causes of infection in neonates, it is associated with grave morbidity and mortality. We describe the evolution of brain parenchymal affectation observed in association with S. marcescens infection in neonates. This retrospective case series details brain ultrasound findings of five neonates with hospital-acquired S. marcescens infection. Neonatal S. marcescens infection with or without associated meningitis can be complicated by brain parenchymal affectation, leading to cerebral abscess formation. It is recommended that all neonates with this infection should undergo neuro-imaging more than once before discharge from hospital; this can be achieved using bedside ultrasonography.

  11. Serratia marcescens osteomyelitis in Cushing's disease.

    Science.gov (United States)

    Martins, Hugo F G; Raposo, Alexandra; Baptista, Isabel; Almeida, Julio

    2015-11-30

    We report a case of a 46-year-old man with fever, hypotension and arthralgias of the ankles and knees after brain surgery for a pituitary tumour causing Cushing's disease. Blood and urine cultures isolated Serratia marcescens; antibiotic susceptibility testing showed sensitivity to piperacillin-tazobactan and ciprofloxacin. Articular MRI showed inflammation and necrosis of both knees and ankles, and left hip and right elbow (compatible with osteomyelitis). Culture of an ankle abscess on the ankle joint was positive for Serratia marcescens. Bone scintigraphy confirmed osteomyelitic lesions. Medical treatment included antibiotics and strong opioid therapy for 14 weeks. The patient was discharged clinically improved maintaining ciprofloxacin for 24 additional weeks based on clinical and analytic recovery.

  12. USE OF A NATURAL DYE FROM SERRATIA MARCESCENS SUBSPECIES MARCESCENS IN DYEING OF TEXTILE FABRICS

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    Ravindra Adivarekar

    2013-06-01

    Full Text Available A strain of Serratia marcescens subspecies marcescens capable of producing a novel rose red pigment with a mass of 112 Da has been isolated from Mahim Mangroove soil. Studies regarding the growth conditions of bacteria, partial characterization of the produced pigment and use of this rose red pigment to dye natural fabrics has been studied and described. Dyeing of wool, cotton and silk fabrics with this rose red microbial pigment as natural dye indicated that the colour strength values and the dye uptake were high with satisfactory fastness properties of the dyed fabric.

  13. Serratia marcescens harboring SME-4 in Brazil: A silent threat.

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    Cayô, Rodrigo; Leme, Rodrigo Cuiabano Paes; Streling, Ana Paula; Matos, Adriana Pereira; Nodari, Carolina Silva; Chaves, Jessica Reis Esteves; Brandão, Jorge Luiz Ferreira; de Almeida, Maíra Fernandes; Carrareto, Valério; de Castro Pereira, Marco Aurélio; de Almeida, Jean Pierre Aquino; Ferreira, Demian Candido; Gales, Ana Cristina

    2017-04-01

    The intrinsic polymyxin resistance displayed by Serratia marcescens makes the acquisition of carbapenemase encoding genes a worrisome event. This study report a SME-4-producing S. marcescens isolate causing septic shock in Brazil. The insertion of novel resistance determinants and their consequent spread in our territory is noteworthy.

  14. Buffering Capacity of Pigmented and Nonpigmented Strains of Serratia marcescens

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    Rius, Núria; Solé, Montserrat; Francia, Alicia; Lorén, José G.

    1994-01-01

    The pigmented strain Serratia marcescens ATCC 274 had a higher buffering capacity and a higher membrane H+ conductance than S. marcescens GP, a spontaneous nonpigmented mutant of ATCC 274. The data suggest that mutations which apparently affect only the synthesis of a secondary metabolite can modify buffering capacity and passive H+ conductance. PMID:16349300

  15. Characterization of Poly(A)-Protein Complexes Isolated from Free and Membrane-Bound Polyribosomes of Ehrlich Ascites Tumor Cells

    NARCIS (Netherlands)

    Janssen, Dick B.; Counotte-Potman, Anda D.; Venrooij, Walther J. van

    1976-01-01

    Proteins present in messenger ribonucleoprotein particles were labeled with [35S]-methionine in Ehrlich ascites tumor cells in which synthesis of new ribosomes was inhibited. Poly(A)-protein complexes were isolated from free and membrane-bound polyribosomes by sucrose gradient centrifugation and aff

  16. Fear learning increases the number of polyribosomes associated with excitatory and inhibitory synapses in the barrel cortex.

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    Malgorzata Jasinska

    Full Text Available Associative fear learning, resulting from whisker stimulation paired with application of a mild electric shock to the tail in a classical conditioning paradigm, changes the motor behavior of mice and modifies the cortical functional representation of sensory receptors involved in the conditioning. It also induces the formation of new inhibitory synapses on double-synapse spines of the cognate barrel hollows. We studied density and distribution of polyribosomes, the putative structural markers of enhanced synaptic activation, following conditioning. By analyzing serial sections of the barrel cortex by electron microscopy and stereology, we found that the density of polyribosomes was significantly increased in dendrites of the barrel activated during conditioning. The results revealed fear learning-induced increase in the density of polyribosomes associated with both excitatory and inhibitory synapses located on dendritic spines (in both single- and double-synapse spines and only with the inhibitory synapses located on dendritic shafts. This effect was accompanied by a significant increase in the postsynaptic density area of the excitatory synapses on single-synapse spines and of the inhibitory synapses on double-synapse spines containing polyribosomes. The present results show that associative fear learning not only induces inhibitory synaptogenesis, as demonstrated in the previous studies, but also stimulates local protein synthesis and produces modifications of the synapses that indicate their potentiation.

  17. Pink Breast Milk: Serratia marcescens Colonization.

    Science.gov (United States)

    Valle, Cipatli Ayuzo Del; Salinas, Emilio Treviño

    2014-11-01

    Background Breast milk can turn pink with Serratia marcescens colonization, this bacterium has been associated with several diseases and even death. It is seen most commonly in the intensive care settings. Discoloration of the breast milk can lead to premature termination of nursing. We describe two cases of pink-colored breast milk in which S. marsescens was isolated from both the expressed breast milk. Antimicrobial treatment was administered to the mothers. Return to breastfeeding was successful in both the cases. Conclusions Pink breast milk is caused by S. marsescens colonization. In such cases,early recognition and treatment before the development of infection is recommended to return to breastfeeding.

  18. Increased cytoplasmic TDP-43 reduces global protein synthesis by interacting with RACK1 on polyribosomes.

    Science.gov (United States)

    Russo, Arianna; Scardigli, Raffaella; La Regina, Federico; Murray, Melissa E; Romano, Nicla; Dickson, Dennis W; Wolozin, Benjamin; Cattaneo, Antonino; Ceci, Marcello

    2017-04-15

    TDP-43 is a well known RNA binding protein involved in the pathogenesis of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Dementia (FTLD). In physiological conditions, TDP-43 mainly localizes in the nucleus and shuttles, at least in neurons, to the cytoplasm to form TDP-43 RNA granules. In the nucleus, TDP-43 participates to the expression and splicing of RNAs, while in the cytoplasm its functions range from transport to translation of specific mRNAs. However, if loss or gain of these TDP-43 functions are affected in ALS/FTLD pathogenesis is not clear. Here, we report that TDP-43 localizes on ribosomes not only in primary neurons but also in SH-SY5Y human neuroblastoma cells. We find that binding of TDP-43 to the translational machinery is mediated by an interaction with a specific ribosomal protein, RACK1, and that an increase in cytoplasmic TDP-43 represses global protein synthesis, an effect which is rescued by overexpression of RACK1. Ribosomal loss of RACK1, which excludes TDP-43 from the translational machinery, remarkably reduces formation of TDP-43 cytoplasmic inclusions in neuroblastoma cells. Finally, we corroborate the interaction between TDP-43 and RACK1 on polyribosomes of neuroblastoma cells with mis-localization of RACK1 on TDP-43 positive cytoplasmic inclusions in motor neurons of ALS patients. In conclusions, results from this study suggest that TDP-43 represents a translational repressor not only for specific mRNAs but for overall translation and that its binding to polyribosomes through RACK1 may promote, under conditions inducing ALS pathogenesis, the formation of cytoplasmic inclusions. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Non-contiguous multifocal vertebral osteomyelitis caused by Serratia marcescens.

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    Lau, Jen Xin; Li, Jordan Yuanzhi; Yong, Tuck Yean

    2015-03-01

    Serratia marcescens is a common nosocomial infection but a rare cause of osteomyelitis and more so of vertebral osteomyelitis. Vertebral osteomyelitis caused by this organism has been reported in few studies. We report a case of S. marcescens vertebral discitis and osteomyelitis affecting multiple non-contiguous vertebras. Although Staphylococcus aureus is the most common cause of vertebral osteomyelitis, rare causes, such as S. marcescens, need to be considered, especially when risk factors such as intravenous heroin use, post-spinal surgery and immunosuppression are present. Therefore, blood culture and where necessary biopsy of the infected region should be undertaken to establish the causative organism and determine appropriate antibiotic susceptibility. Prompt diagnosis of S. marcescens vertebral osteomyelitis followed by the appropriate treatment can achieve successful outcomes.

  20. Serratia marcescens: an unusual pathogen associated with snakebite cellulitis.

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    Subramani, Parimala; Narasimhamurthy, Gokul Bindiganavile; Ashokan, Bhaskaran; Madappa, Beena Prasavangada

    2013-02-15

    This study reports a case of Serratia marcescens cellulitis following a snakebite in a 50-year-old woman. The bite was on the dorsum of the right hand with symptoms of envenomation. She developed swelling and cellulitis with tissue necrosis. Wound debridement was performed.  Pus and tissue biopsy cultures yielded Serratia marcescens sensitive to fluoroquinolones, aminoglycosides, third-generation cephalosporins and carbapenems. The patient responded to anti-snake venom (ASV) therapy, ciprofloxacin, local wound management and recovered uneventfully.

  1. ANTAGONISTIC ACTIVITY OF SERRATIA MARCESCENS AGAINST PYRICULARIA ORYZAE

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    V. JAIGANESH

    2007-08-01

    Full Text Available Rice is an important crop, widely affected by quite a number of diseases that results in higher yield losses. Among the fungal diseases, blast incited by Pyricularia oryzae is a major disease. The biological method of plant disease management seems to be an alternative to chemical fungicides in managing the blast disease. A new bio control agent viz., Serratia marcescens appears to be an ideal agent for the control of P. oryzae, because it produces chitinolytic enzymes which causes degradation of the fungal cell walls, induction of plant defence reaction and certain antifungal low molecular weight molecules. A study was undertaken to investigate the effect of a new bio control agent like S. marcescens against P. oryzae. The talc based formulation of S. marcescens (@ 1.0, 1.5, 2.0 and 2.5 kg/ha was sprayed on old IR 50 rice plants in fields. Out of the six-bio protectants tested, S. marcescens was found very effective against P. oryzae under in vitro conditions. S. marcescens could be isolated from shoots as well as roots emerging from the treated seeds and the plant parts from treated seeds inhibited P. oryzae. The antagonist S. marcescens survived in the phyllosphere even 80 days after spray. The results revealed that rice blast control was achieved by spraying S. marcescens @ 1.0 kg/ha. The increasing dose of talc-based inoculum when applied on foliage increased the phyllosphere population of S. marcescens and controlled rice blast. The maximum disease control was achieved when inoculum was applied at 2.5 kg/ha.

  2. Serratia marcescens is injurious to intestinal epithelial cells.

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    Ochieng, John B; Boisen, Nadia; Lindsay, Brianna; Santiago, Araceli; Ouma, Collins; Ombok, Maurice; Fields, Barry; Stine, O Colin; Nataro, James P

    2014-01-01

    Diarrhea causes substantial morbidity and mortality in children in low-income countries. Although numerous pathogens cause diarrhea, the etiology of many episodes remains unknown. Serratia marcescens is incriminated in hospital-associated infections, and HIV/AIDS associated diarrhea. We have recently found that Serratia spp. may be found more commonly in the stools of patients with diarrhea than in asymptomatic control children. We therefore investigated the possible enteric pathogenicity of S. marcescens in vitro employing a polarized human colonic epithelial cell (T84) monolayer. Infected monolayers were assayed for bacterial invasion, transepithelial electrical resistance (TEER), cytotoxicity, interleukin-8 (IL-8) release and morphological changes by scanning electron microscopy. We observed significantly greater epithelial cell invasion by S. marcescens compared to Escherichia coli strain HS (p = 0.0038 respectively). Cell invasion was accompanied by reduction in TEER and secretion of IL-8. Lactate dehydrogenase (LDH) extracellular concentration rapidly increased within a few hours of exposure of the monolayer to S. marcescens. Scanning electron microscopy of S. marcescens-infected monolayers demonstrated destruction of microvilli and vacuolization. Our results suggest that S. marcescens interacts with intestinal epithelial cells in culture and induces dramatic alterations similar to those produced by known enteric pathogens.

  3. Additive and synergistic effects of kinetin and ethrel on germination, thermodormany, and polyribosome formation in lettuce seeds.

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    Rao, V S; Sankhla, N; Khan, A A

    1975-08-01

    The inhibition of germination of Grand Rapids lettuce (Lactuca sativa L.) seeds at 35 C was removed to a marked extent by kinetin and 2-chloroethylphosphonic acid (ethrel). When both compounds were used together, an additive effect was observed. A synergistic effect was, however, noted when ethrel promoted the kinetin reversal of abscisic acid inhibition of seed germination (light- as well as gibberellic acid-, induced). Both kinetin and ethrel increased the total ribosomal material and the percentage of polyribosomes in lettuce seeds imbibed in the light for 24 hours. A combination of the two compounds showed a synergism in polyribosome formation only at high ethrel concentration. The inability of ethrel to reverse abscisic acid inhibition indicates that kinetin action cannot always be substituted by ethrel. The possible mechanisms involved in the enhanced response by a combination of kinetin and ethrel are discussed.

  4. Highly Solvent Tolerance in Serratia marcescens IBBPo15

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    Mihaela Marilena Stancu

    Full Text Available ABSTRACT The aim of this study was to investigate the solvent tolerance mechanisms in Serratia marcescens strain IBBPo15 (KT315653. Serratia marcescens IBBPo15 exhibited remarkable solvent-tolerance, being able to survive in the presence of high concentrations (above 40% of toxic organic solvents, such as cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. S. marcescens IBBPo15 produced extracellular protease and the enzyme production decreased in cells exposed to 5% cyclohexane, n-hexane, toluene, styrene, and ethylbenzene, as compared with the control and n-decane exposed cells. S. marcescens IBBPo15 cells produced carotenoid pigments and alteration of pigments profile (i.e., phytoene, lycopene were observed in cells exposed to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. The exposure of S. marcescens IBBPo15 cells to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, ethylbenzene induced also changes in the intracellular (e.g., 50 kDa protein and extracellular (e.g., 39, 41, 43, 53, 110 kDa proteins proteins profile. Significant RAPD, ARDRA, rep-PCR and PCR pattern modifications were not observed in DNA extracted from S. marcescens IBBPo15 cells exposed to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. Though only HAE1 and acrAB genes were detected in the genome of S. marcescens IBBPo15 cells, the unspecific amplification of other fragments being observed also when the primers for ompF and recA genes were used.

  5. STRUCTURAL AND PHYSICOCHEMICAL SURFACE-PROPERTIES OF SERRATIA-MARCESCENS STRAINS

    NARCIS (Netherlands)

    VANDERMEI, HC; COWAN, MM; GENET, MJ; ROUXHET, PG; BUSSCHER, HJ

    1992-01-01

    Serratia marcescens is an important pathogen with noteworthy hydrophobicity characteristics as assessed by microbial adhesion to hydrocarbons. However, the present knowledge on the surface characteristics of S. marcescens strains does not include physicochemical properties relevant for adhesion such

  6. STRUCTURAL AND PHYSICOCHEMICAL SURFACE-PROPERTIES OF SERRATIA-MARCESCENS STRAINS

    NARCIS (Netherlands)

    VANDERMEI, HC; COWAN, MM; GENET, MJ; ROUXHET, PG; BUSSCHER, HJ

    1992-01-01

    Serratia marcescens is an important pathogen with noteworthy hydrophobicity characteristics as assessed by microbial adhesion to hydrocarbons. However, the present knowledge on the surface characteristics of S. marcescens strains does not include physicochemical properties relevant for adhesion such

  7. Production and toxicological evaluation of Prodigiosin from Serratia marcescens UCP/WFCC1549 on Mannitol Solid Medium

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    J. C. Lapenda Lins

    2014-05-01

    Full Text Available Summary. Prodigiosins, a family of natural red pigments, were produced by a new strain of Serratia marcescens UCP/WFCC1549 using peptone-glycerol and mannitol solid media. Prodigiosin is a secondary metabolite alkaloid (5((3-methoxy-5-pyrrol-2-ylidene-pyrrol-2-ylidene-methyl-2-methyl-3-pentyl-1H-pyrrole with a unique tripyrrole chemical structure, and has antimicrobial, antimalarial, antimycotic, immunomodulating, antitumor and anti-proliferative properties. The mannitol medium produced a high amount of biomass, and the red pigment was extracted by methanol and scanned at 200-700nm. The raw pigment was purified by exclusion chromatography by Sephadex LH-20, resulting in 96 fractions. The isolated red pigment was analyzed by electrospray ionization mass spectrometry (GC-MS, its molecular weight was 323.4Da, and it was identified as Prodigiosin. Cytotoxic activity using Artemia salina showed LC50=78.33 µg/mL.Industrial relevance. Prodigiosin produced by Serratia marcescens is a promising drug owing to its reported characteristics of having antifungal, anti-microbial, anti-malarial, anti-cancer and immunosuppressive properties. Of these, its immunosuppressive and anti-cancer activities have received greatest attention because they have clinical promise. From the point of view of industrial production, we obtained a suitable medium so as simultaneously to enhance the growth of Serratia marcescens UCP/WFCC1549 and production of the pigment. The red purified fraction was identified as Prodigiosin and is a promising molecule owing to its low toxicity and potential for therapeutic application in the future.Keywords. cytotoxicity; mannitol medium; mass spectrometry; phytotoxicity; Serratia marcescens; Prodigiosin.

  8. Identification of a Csr system in Serratia marcescens 2170.

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    Ito, Manabu; Nomura, Kazuki; Sugimoto, Hayuki; Watanabe, Takeshi; Suzuki, Kazushi

    2014-01-01

    The carbon storage regulator (Csr) global regulatory system is conserved in many eubacteria and coordinates the expression of various genes that facilitate adaptation during the major physiological growth phase. The Csr system in Escherichia coli comprises an RNA-binding protein, CsrA; small non-coding RNAs, CsrB and CsrC; and a decay factor for small RNAs, CsrD. In this study, we identified the Csr system in Serratia marcescens 2170. S. marcescens CsrA was 97% identical to E. coli CsrA. CsrB and CsrC RNAs had typical stem-loop structures, including a GGA motif that is the CsrA binding site. CsrD was composed of N-terminal two times transmembrane region and HAMP-like, GGDEF, and EAL domains. Overexpression of S. marcescens csr genes complemented the phenotype of E. coli csr mutants. S. marcescens CsrD affected the decay of CsrB and CsrC RNAs in E. coli. These results suggest that the Csr system in S. marcescens is composed of an RNA-binding protein, two Csr small RNAs, and a decay factor for Csr small RNAs.

  9. Plasmid-determined resistance to fosfomycin in Serratia marcescens.

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    Mendoza, C; Garcia, J M; Llaneza, J; Mendez, F J; Hardisson, C; Ortiz, J M

    1980-08-01

    Multiple-antibiotic-resistant strains of Serratia marcescens isolated from hospitalized patients were examined for their ability to transfer antibiotic resistance to Escherichia coli by conjugation. Two different patterns of linked transferable resistance were found among the transconjugants. The first comprised resistance to carbenicillin, streptomycin, and fosfomycin; the second, and more common, pattern included resistance to carbenicillin, streptomycin, kanamycin, gentamicin, tetracycline, chloramphenicol, sulfonamide, and fosfomycin. The two types of transconjugant strains carried a single plasmid of either 57 or 97 megadaltons in size. Both of these plasmids are present in parental S. marcescens strains resistant to fosfomycin. The 57-megadalton plasmid was transformed into E. coli.

  10. Serratia marcescens spinal epidural abscess formation following acupuncture.

    Science.gov (United States)

    Yang, Chih-Wei; Hsu, Shun-Neng; Liu, Jhih-Syuan; Hueng, Dueng-Yuan

    2014-01-01

    The formation of spinal epidural abscess following acupuncture is very rare. We herein report the case of a 54-year-old woman who presented with progressive low back pain and fever with a root sign. She underwent surgical decompression, with an immediate improvement of the low back pain. A culture of the epidural abscess grew Serratia marcescens. One year postoperatively, magnetic resonance imaging revealed the almost complete eradication of the abscess. This case is the first case of Serratia marcescens-associated spinal epidural abscess formation secondary to acupuncture. The characteristics of spinal epidural abscess that develop after acupuncture and how to prevent such complications are also discussed.

  11. Outbreak of meningitis due to Serratia marcescens after spinal anaesthesia.

    Science.gov (United States)

    Ersoz, G; Uguz, M; Aslan, G; Horasan, E S; Kaya, A

    2014-06-01

    This article describes an outbreak of meningitis caused by Serratia marcescens in patients who had undergone spinal anaesthesia for caesarean section. Bacterial meningitis was diagnosed in 12 of the 46 patients who underwent a caesarean section under spinal anaesthesia in a 75-bed private hospital between 6(th) and 14(th) March 2011. S. marcescens was isolated from samples taken from four prefilled syringes and one bag containing 5% dextrose with norepinephrine, suggesting that medications used in spinal anaesthesia were contaminated extrinsically. Strategies for prevention of anaesthesia-associated infections in operating theatres are discussed.

  12. Antibiotic susceptibility of Serratia marcescens and Serratia liquefaciens.

    Science.gov (United States)

    Traub, W H

    2000-01-01

    Over a period of 20 years, a total of 1,603 Serratia isolates were recovered from clinical specimens and examined for susceptibility to 29 antimicrobial drugs using the Bauer-Kirby agar disk diffusion test. Serratia marcescens was recovered most frequently (n = 1,409), followed by S. liquefaciens (n = 172); other Serratia species were scarce. During the 2-decade observation period there occurred 35 putative episodes/clusters of nosocomial cross-infection and 1 pseudo-outbreak due to S. marcescens, but none due to S. liquefaciens. The antimicrobial susceptibility data for S. marcescens and S. liquefaciens were subdivided into two observation periods: I = 1980-1993, and II = 1993-1999. The crude data (series A) obtained for S. marcescens were corrected in two ways: by the omission of repetitive patient isolates (series B) and the additional removal of outbreak isolates except for index case isolates (series C). Comparison of data obtained in series IC and IIC disclosed an increase in the susceptibility of S. marcescens to ampicillin + sulbactam, cefotaxime, chloramphenicol, doxycycline, fosfomycin, gentamicin, piperacillin, piperacillin + tazobactam, timentin and tobramycin during observation period II. Conversely, there was a decrease in susceptibility to ciprofloxacin, nalidixic acid and trovafloxacin, and slightly diminished susceptibility to norfloxacin and ofloxacin during observation period II as compared with the previous period. The crude data obtained for S. liquefaciens required no correction, as there were only a few repeat isolates. There was an increase in susceptibility to ampicillin, ampicillin + sulbactam, cefuroxime, doxycycline, fosfomycin, nitrofurantoin and polymyxin B (clear inhibition zones). However, there was an inexplicable decrease in susceptibility to piperacillin + tazobactam. Cocarde growth around polymyxin B disks was noted with 55.8% of the S. marcescens isolates as compared with 6.8% of the S. liquefaciens isolates. Slime around

  13. Risk Factors for Mortality in Patients with Serratia marcescens Bacteremia

    Science.gov (United States)

    Kim, Sun Bean; Jeon, Yong Duk; Kim, Jung Ho; Kim, Jae Kyoung; Ann, Hea Won; Choi, Heun; Kim, Min Hyung; Song, Je Eun; Ahn, Jin Young; Jeong, Su Jin; Han, Sang Hoon; Choi, Jun Yong; Song, Young Goo; Kim, June Myung

    2015-01-01

    Purpose Over the last 30 years, Serratia marcescens (S. marcescens) has emerged as an important pathogen, and a common cause of nosocomial infections. The aim of this study was to identify risk factors associated with mortality in patients with S. marcescens bacteremia. Materials and Methods We performed a retrospective cohort study of 98 patients who had one or more blood cultures positive for S. marcescens between January 2006 and December 2012 in a tertiary care hospital in Seoul, South Korea. Multiple risk factors were compared with association with 28-day all-cause mortality. Results The 28-day mortality was 22.4% (22/98 episodes). In a univariate analysis, the onset of bacteremia during the intensive care unit stay (p=0.020), serum albumin level (p=0.011), serum C-reactive protein level (p=0.041), presence of indwelling urinary catheter (p=0.023), and Sequential Oran Failure Assessment (SOFA) score at the onset of bacteremia (p<0.001) were significantly different between patients in the fatal and non-fatal groups. In a multivariate analysis, lower serum albumin level and an elevated SOFA score were independently associated with 28-day mortality [adjusted odds ratio (OR) 0.206, 95% confidential interval (CI) 0.044-0.960, p=0.040, and adjusted OR 1.474, 95% CI 1.200-1.810, p<0.001, respectively]. Conclusion Lower serum albumin level and an elevated SOFA score were significantly associated with adverse outcomes in patients with S. marcescens bacteremia. PMID:25683980

  14. Mechanisms of Bacterial (Serratia marcescens) Attachment to, Migration along, and Killing of Fungal Hyphae

    OpenAIRE

    Hover, Tal; Maya, Tal; Ron, Sapir; Sandovsky, Hani; Shadkchan, Yana; Kijner, Nitzan; Mitiagin, Yulia; Fichtman, Boris; Harel, Amnon; Shanks, Robert M. Q.; Bruna, Roberto E.; García-Véscovi, Eleonora; Osherov, Nir

    2016-01-01

    We have found a remarkable capacity for the ubiquitous Gram-negative rod bacterium Serratia marcescens to migrate along and kill the mycelia of zygomycete molds. This migration was restricted to zygomycete molds and several basidiomycete species. No migration was seen on any molds of the phylum Ascomycota. S. marcescens migration did not require fungal viability or surrounding growth medium, as bacteria migrated along aerial hyphae as well. S. marcescens did not exhibit growth tropism toward ...

  15. Serratia marcescens endogenous endophthalmitis in an immunocompetent host.

    Science.gov (United States)

    Memon, Muhammad; Raman, Vasant

    2016-01-20

    A systemically well 66-year-old white Caucasian man presented to the urgent care department with a short history of progressive pain and blurring of vision in his left eye. He denied a history of trauma, intraocular surgery or use of illicit drugs. He was diagnosed with endogenous endophthalmitis. Vitreous biopsy grew Serratia marcescens, a Gram negative bacteria. In spite of extensive investigation, there was no obvious source of infection. He had an indwelling urine catheter for prostate hypertrophy, but urine culture was negative. There was no evidence of immunocompromise. He was treated with systemic as well as intravitreal antibiotics. In spite of appropriate treatment, the patient lost vision. S. marcescens endophthalmitis, seen even in immunocompetent people, carries a poor visual prognosis.

  16. Morphological and intracellular alterations induced by Serratia marcescens cytotoxin.

    Science.gov (United States)

    Carbonell, Gleize Villela; Falcón, Rosabel; Yamada, Aureo T; da Fonseca, Benedito Antonio Lopes; Yano, Tomomasa

    2004-01-01

    In the present work, in vitro assays were used to investigate the toxicity of Serratia marcescens cytotoxin in cultured Chinese hamster ovary (CHO) cells. The time necessary to detect cellular alterations such as the onset of apoptosis, the perturbation of mitochondrial function, and cytoskeletal changes was assessed. The internalization of the cytotoxin by CHO cells was also examined. Within 10-15 min of exposure to cytotoxin, CHO cells became round, the nucleus shrank, the chromatin became more compact, and cytoplasmic blebs appeared on the cell surface. TUNEL (TdT-mediated dUTP nick end labeling) and propidium iodide staining identified some nuclei with fragmented DNA, and electrophoresis of CHO cell DNA obtained after 30-min exposure to S. marcescens toxin showed a pattern of DNA fragments typically associated with apoptosis. The cells also lost their characteristic actin organization within 10 min of exposure to cytotoxin. Lactate dehydrogenase leakage was detected after 20-min exposure to the cytotoxin and increased with time thereafter. Concomitantly, there was a time-dependent reduction in mitochondrial activity. Fluorescein-labeled S. marcescens cytotoxin was detected only on the surface of CHO cells, even after 30-min exposure to the toxin. These results show that there was no internalization of the toxin by CHO cells, and that, once bound to the cell surface, the toxin was able to induce changes in intracellular metabolism and to trigger cell death by apoptosis.

  17. Reseach Progress on Serratia marcescens Non-specific Nuclease%Serratia marcescens 非特异性核酸酶研究进展

    Institute of Scientific and Technical Information of China (English)

    张瑜; 郑伟; 顾剑飞; 石陆娥

    2016-01-01

    Serratia marcescens nuclease is a non-specific endonuclease, which is able to cleave different forms of DNA and RNA.The cleavage sites and the catalytic mechanism of the non-specific nuclease of Serratia marcescen, its characteristics of the degrade substrate were mainly summarized.In addition, the research on prokaryotic expression and application of this nuclease was briefly introduced in order to provide the theoretical basis for further research of Serratia marcescens non-specific nuclease.%Serratia marcescens 核酸酶是一种非特异性核酸内切酶,可降解不同形式的 DNA 和 RNA。本文综合国内外的研究概况,主要介绍了 Serratia marcescens 非特异性核酸酶的水解位点、催化机制及其降解底物的特点,另外也阐述了 Serratia marcescens 非特异性核酸酶的原核表达的研究以及其应用现状,为 Serratia marcescens 非特异性核酸酶更深层次的研究提供理论基础。

  18. Characterization of the gacA-dependent surface and coral mucus colonization by an opportunistic coral pathogen Serratia marcescens PDL100.

    Science.gov (United States)

    Krediet, Cory J; Carpinone, Emily M; Ritchie, Kim B; Teplitski, Max

    2013-05-01

    Opportunistic pathogens rely on global regulatory systems to assess the environment and to control virulence and metabolism to overcome host defenses and outcompete host-associated microbiota. In Gammaproteobacteria, GacS/GacA is one such regulatory system. GacA orthologs direct the expression of the csr (rsm) small regulatory RNAs, which through their interaction with the RNA-binding protein CsrA (RsmA), control genes with functions in carbon metabolism, motility, biofilm formation, and virulence. The csrB gene was controlled by gacA in Serratia marcescens PDL100. A disruption of the S. marcescens gacA gene resulted in an increased fitness of the mutant on mucus of the host coral Acropora palmata and its high molecular weight fraction, whereas the mutant was as competitive as the wild type on the low molecular weight fraction of the mucus. Swarming motility and biofilm formation were reduced in the gacA mutant. This indicates a critical role for gacA in the efficient utilization of specific components of coral mucus and establishment within the surface mucopolysaccharide layer. While significantly affecting early colonization behaviors (coral mucus utilization, swarming motility, and biofilm formation), gacA was not required for virulence of S. marcescens PDL100 in either a model polyp Aiptasia pallida or in brine shrimp Artemia nauplii.

  19. Ocorrência de Serratia marcescens bizio sobre lagartas de Heliothis virescens (Fabr. Occurrence of Serratia marcescens bizio on Heliothis virescens (Fabr.

    Directory of Open Access Journals (Sweden)

    Margarida Fumiko Ito

    1996-01-01

    Full Text Available Observou-se, em laboratório, grande número de lagartas mortas em uma criação de Heliothis virescens (Fabr.. Dessas lagartas, isolou-se uma bactéria, posteriormente identificada como Serratia marcescens Bizio. O presente trabalho registra sua ocorrência e comprova-lhe a patogenicidade sobre aquelas lagartas.A large quantity of dead worms was observed in rearing of Heliothis virescens. A bacteria, later identified as Serratia marcescens Bizio, was isolated from the dead worms. The present work registers the occurrence and confirms the pathogenicity of S. marcescens on H. virescens.

  20. Quorum Sensing Regulation of Adhesion in Serratia Marcescens MG1 is surface dependent

    DEFF Research Database (Denmark)

    Labbate, M.; Zhu, H.; Thung, L.;

    2007-01-01

    Serratia marcescens is an opportunistic pathogen and a major cause of ocular infections. In previous studies of S. marcescens MG1, we showed that biofilm maturation and sloughing were regulated by N-acyl homoserine lactone (AHL)-based quorum sensing (QS). Because of the importance of adhesion...

  1. CHITINASE-B FROM SERRATIA-MARCESCENS-BJL200 IS EXPORTED TO THE PERIPLASM WITHOUT PROCESSING

    NARCIS (Netherlands)

    BRURBERG, MB; EIJSINK, VGH; HAANDRIKMAN, AJ; VENEMA, G; NES, IF

    1995-01-01

    A gene encoding a chitinase from Serratia marcescens BJL200 was cloned and expressed in Escherichia coli and S. marcescens. Nucleotide sequencing revealed an open reading frame encoding a 55.5 kDa protein of 499 amino acids without a typical signal peptide for export. The cellular localization of th

  2. The inhibitory effect of a Lactobacillus acidophilus derived biosurfactant on Serratia marcescens biofilm formation

    Directory of Open Access Journals (Sweden)

    Maliheh Shokouhfard

    2015-10-01

    Results: The FTIR analysis of derived biosurfactant revealed the composition as protein component. Because of the release of such biosurfactants, L. acidophilus was able to interfere with the adhesion and biofilm formation of the S. marcescens strains. In co- incubation method this biosurfactant in 2.5 mg/ml concentration showed anti-adhesive activity against all tested strains of S. marcescens (P

  3. The formation of polyribosomes during the germination of grains of wheat of different ripeness

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    Stanisław Weidner

    2014-01-01

    Full Text Available The total ribosomal fraction was isolated from whole seedlings from grains of wheat gathered at the milk-, milk-wax and full-ripeness stages. A gradual increase in the amount of the total ribosomal fraction was observed during germination until the 6th day in all of the studied groups. From the 6th to 12th days of germination a decrease in this, fraction was found. In all of these groups polysomes constituted 88-90% of the total ribosomal fraction after 48 hrs of germination. From the 2nd to the 12th day, polysomes made up a decreasing percentage of the total ribosomal fraction. The percentage of polysomes contained in this fraction at the begining (0-24 h as well as at the end (10-12th day of the studied period of germination of immature grains was lower than in mature ones, which is synonymous with a lower level of protein synthesis in their tissues. When the results were calculated per seedling, it was shown that the less mature the grain, the lower the total ribosome content. These results show that grains gathered at full ripeness are the most vigorous.

  4. Tracking the Fragile X Mental Retardation Protein in a Highly Ordered Neuronal RiboNucleoParticles Population: A Link between Stalled Polyribosomes and RNA Granules

    Science.gov (United States)

    Tremblay, Sandra; Jaglin, Xavier; Dury, Alain; Robert, Claude; De Koninck, Paul; Khandjian, Edouard W.

    2016-01-01

    Local translation at the synapse plays key roles in neuron development and activity-dependent synaptic plasticity. mRNAs are translocated from the neuronal soma to the distant synapses as compacted ribonucleoparticles referred to as RNA granules. These contain many RNA-binding proteins, including the Fragile X Mental Retardation Protein (FMRP), the absence of which results in Fragile X Syndrome, the most common inherited form of intellectual disability and the leading genetic cause of autism. Using FMRP as a tracer, we purified a specific population of RNA granules from mouse brain homogenates. Protein composition analyses revealed a strong relationship between polyribosomes and RNA granules. However, the latter have distinct architectural and structural properties, since they are detected as close compact structures as observed by electron microscopy, and converging evidence point to the possibility that these structures emerge from stalled polyribosomes. Time-lapse video microscopy indicated that single granules merge to form cargoes that are transported from the soma to distal locations. Transcriptomic analyses showed that a subset of mRNAs involved in cytoskeleton remodelling and neural development is selectively enriched in RNA granules. One third of the putative mRNA targets described for FMRP appear to be transported in granules and FMRP is more abundant in granules than in polyribosomes. This observation supports a primary role for FMRP in granules biology. Our findings open new avenues for the study of RNA granule dysfunctions in animal models of nervous system disorders, such as Fragile X syndrome. PMID:27462983

  5. Pink hypopyon in a patient with Serratia marcescens corneal ulceration.

    Science.gov (United States)

    Stefater, James A; Borkar, Durga S; Chodosh, James

    2015-01-01

    A 65-year-old woman presented to the emergency ward at the Massachusetts Eye and Ear Infirmary with 2 days of redness, irritation, photophobia, and diminished vision in her left eye. She was found to have a large central corneal ulcer with a small hypopyon. On the following day, after initiation of broad-spectrum antibiotics, the patient had improved symptoms but now had a 2-mm hypopyon that was distinctly pink in color. Cultures were positive for Serratia marcescens. A pink hypopyon, a rare occurrence, alerted the authors to a causative agent of Enterobacteriacae, either Klebsiella or Serratia. Immediate and intensive treatment was subsequently initiated.

  6. Mechanisms of Bacterial (Serratia marcescens) Attachment to, Migration along, and Killing of Fungal Hyphae.

    Science.gov (United States)

    Hover, Tal; Maya, Tal; Ron, Sapir; Sandovsky, Hani; Shadkchan, Yana; Kijner, Nitzan; Mitiagin, Yulia; Fichtman, Boris; Harel, Amnon; Shanks, Robert M Q; Bruna, Roberto E; García-Véscovi, Eleonora; Osherov, Nir

    2016-05-01

    We have found a remarkable capacity for the ubiquitous Gram-negative rod bacterium Serratia marcescens to migrate along and kill the mycelia of zygomycete molds. This migration was restricted to zygomycete molds and several basidiomycete species. No migration was seen on any molds of the phylum Ascomycota. S. marcescens migration did not require fungal viability or surrounding growth medium, as bacteria migrated along aerial hyphae as well.S. marcescens did not exhibit growth tropism toward zygomycete mycelium. Bacterial migration along hyphae proceeded only when the hyphae grew into the bacterial colony. S. marcescens cells initially migrated along the hyphae, forming attached microcolonies that grew and coalesced to generate a biofilm that covered and killed the mycelium. Flagellum-defective strains of S. marcescens were able to migrate along zygomycete hyphae, although they were significantly slower than the wild-type strain and were delayed in fungal killing. Bacterial attachment to the mycelium does not necessitate type 1 fimbrial adhesion, since mutants defective in this adhesin migrated equally well as or faster than the wild-type strain. Killing does not depend on the secretion of S. marcescens chitinases, as mutants in which all three chitinase genes were deleted retained wild-type killing abilities. A better understanding of the mechanisms by which S. marcescens binds to, spreads on, and kills fungal hyphae might serve as an excellent model system for such interactions in general; fungal killing could be employed in agricultural fungal biocontrol.

  7. ISOLATION AND CHARACTERIZATION OF A NOVEL BENZOATE- UTILIZING Serratia marcescens

    Directory of Open Access Journals (Sweden)

    ANTONIUS SUWANTO

    2003-01-01

    Full Text Available A new benzoate-utilizing strain, Serratia marcescens DS-8, isolated from the environment was characterized. The strain was enterobacilli, Gram negative, mesophilic, non ha lophilic, and aerobic bacterium that showed motile ovale-rod shaped cells. The isolate produced extracellular chitinase, protease, and prodigiosin (a red pigment pr oduced by several Serratia strains yielding bright red or pink colonies. A physiological assay using Microbact* test showed that the strain was closely related to Klebsiella ozaenae (49.85% and Serratia liquefaciens (24.42%, respectively. However, 16S rRNA sequence analysis indicated that the strain was closely related to S. marcescens DSM 30121 with similarity level of 98%. DS-8 strain was able to synthesize its own vitamins. Optimum growth in benzoate was obtained at pH between 7-8.5 and NaCl concentration of 1- 1.5% (w/v. The isolate could grow in benzoate-containing medium up to 10 mM. Other carbon sources that could support the growth of DS-8 were casamino acid, glutamate, glucose, acetate, potato star ch, and ethanol.

  8. Serratamolide is a hemolytic factor produced by Serratia marcescens.

    Directory of Open Access Journals (Sweden)

    Robert M Q Shanks

    Full Text Available Serratia marcescens is a common contaminant of contact lens cases and lenses. Hemolytic factors of S. marcescens contribute to the virulence of this opportunistic bacterial pathogen. We took advantage of an observed hyper-hemolytic phenotype of crp mutants to investigate mechanisms of hemolysis. A genetic screen revealed that swrW is necessary for the hyper-hemolysis phenotype of crp mutants. The swrW gene is required for biosynthesis of the biosurfactant serratamolide, previously shown to be a broad-spectrum antibiotic and to contribute to swarming motility. Multicopy expression of swrW or mutation of the hexS transcription factor gene, a known inhibitor of swrW expression, led to an increase in hemolysis. Surfactant zones and expression from an swrW-transcriptional reporter were elevated in a crp mutant compared to the wild type. Purified serratamolide was hemolytic to sheep and murine red blood cells and cytotoxic to human airway and corneal limbal epithelial cells in vitro. The swrW gene was found in the majority of contact lens isolates tested. Genetic and biochemical analysis implicate the biosurfactant serratamolide as a hemolysin. This novel hemolysin may contribute to irritation and infections associated with contact lens use.

  9. Serratia marcescens Bullous Cellulitis in a Splenectomized Patient: A Case Report and Review of the Literature.

    Science.gov (United States)

    Fournier, John B; Dabiri, Ganary; Thomas, Vinod; Skowron, Gail; Carson, Polly; Falanga, Vincent

    2016-06-01

    Serratia marcescens is a Gram-negative bacillus belonging to the Enterobacteriaceae family. Cutaneous infection with Serratia is rare, and usually occurs in immunocompromised individuals. Primary cutaneous infections are uncommon, but they are typically severe and are associated with significant morbidity and mortality. The pathogenetic factors leading to S. marcescens infection are not fully understood, but contributing virulence factors include proteases, secreted exotoxins, and the formation of biofilm. We report a case of cellulitis occurring in a splenectomized patient, which led to multiple wound debridements and a transmetatarsal amputation. This dramatic case led us to review the published literature on soft tissue infections caused by S. marcescens.

  10. Outbreak of postoperative empyema caused by Serratia marcescens in a thoracic surgery unit.

    Science.gov (United States)

    Ulu-Kilic, A; Parkan, O; Ersoy, S; Koc, D; Percin, D; Onal, O; Metan, G; Alp, E

    2013-11-01

    An increase in the number of cases of postoperative empyema due to S. marcescens was recognized in the intensive care unit (ICU) of our Division of Thoracic Surgery between 3 and 19 March 2013. Pleural samples from patients and environmental samples from the operating room and ICU were obtained. A total of eight isolates (six from pleural fluid and two from portable suction devices in ICU) were identified as Serratia marcescens. All isolates were found to be identical by repetitive sequence-based polymerase chain reaction. This is the first report of an outbreak caused by S. marcescens related to a contaminated portable suction machine.

  11. Necrotizing Fasciitis of the Lower Extremity Caused by Serratia marcescens A Case Report.

    Science.gov (United States)

    Heigh, Evelyn G; Maletta-Bailey, April; Haight, John; Landis, Gregg S

    2016-03-01

    Necrotizing fasciitis is a rare and potentially fatal infection, with mortality of up to 30%. This case report describes a patient recovering from a laryngectomy for laryngeal squamous cell cancer who developed nosocomial necrotizing fasciitis of the lower extremity due to Serratia marcescens . Only eight cases of necrotizing fasciitis exclusive to the lower extremity due to S marcescens have been previously reported. Patients with S marcescens necrotizing fasciitis of the lower extremity often have multiple comorbidities, are frequently immunosuppressed, and have a strikingly high mortality rate.

  12. Emergence of Serratia marcescens isolates possessing carbapenem-hydrolysing β-lactamase KPC-2 from China.

    Science.gov (United States)

    Lin, X; Hu, Q; Zhang, R; Hu, Y; Xu, X; Lv, H

    2016-09-01

    Eighty-three carbapenem-resistant Serratia marcescens isolates were recovered from Zhejiang Provincial People's Hospital, China. The minimum inhibitory concentrations of imipenem, meropenem, and ertapenem for all isolates were 2 to >128 μg/mL. Polymerase chain reaction indicated that 63 S. marcescens isolates produced Klebsiella pneumoniae carbapenemase (KPC)-2. Clone A (15 isolates) and clone B (41 isolates) were the two dominant clones and clone A strains were gradually replaced by clone B strains between 2011 and 2014. The results indicate that blaKPC-2-positive S. marcescens emerged in our hospital as the major mechanism of carbapenem resistance.

  13. Skin Abscess due to Serratia marcescens in an Immunocompetent Patient after Receiving a Tattoo

    Directory of Open Access Journals (Sweden)

    J. Diranzo García

    2015-01-01

    Full Text Available The incidence of skin infections caused by Serratia marcescens is extremely low and such infections are typically observed in immunocompromised patients. The clinical manifestations of these infections include cellulitis, abscesses, fluctuant nodules, or granulomatous lesions. Infections caused by S. marcescens are very difficult to treat due to their resistance to many antibiotics, which often leads to specific and prolonged treatment. Infections after receiving a tattoo are very rare and are caused by unhygienic conditions or the inexperience of the tattooist. In this paper we present the case of a 32-year-old male with no comorbidity, who presented an abscess caused by S. marcescens in a area that was tattooed one month earlier. The case was resolved with surgery and antimicrobial therapy that was based on the antibiogram. To our knowledge, this is the first reported case of a S. marcescens skin infection following a tattoo, in the absence of immunosuppression.

  14. Optimized production of Serratia marcescens B742 mutants for preparing chitin from shrimp shells powders.

    Science.gov (United States)

    Zhang, Hongcai; Fang, Jiyang; Deng, Yun; Zhao, Yanyun

    2014-08-01

    To improve the deproteinization (DP) efficacy of shrimp shell powders (SSP) for preparing chitin, Serratia marcescens B742 mutants were prepared using 2% diethyl sulfate (DES), UV-irradiation, and/or microwave heating treatments. Both single-stage and multi-stage mutations were investigated for optimizing S. marcescens B742 mutation conditions. Under the optimized mutation conditions (2% DES treatment for 30min plus successive 20min UV-irradiation), the protease and chitosanase activity produced by mutant S. marcescens B742 was 240.15 and 170.6mU/mL, respectively, as compared with 212.58±1.51 and 83.75±6.51mU/mL, respectively, by wild S. marcescens B742. DP efficacy of SSP by mutant S. marcescens B742 reached 91.4±4.6% after 3d of submerged fermentation instead of 83.4±4.7% from the wild S. marcescens B742 after 4d of submerged fermentation. Molecular mass of chitosanase and protease was 41.20 and 47.10kDa, respectively, and both enzymes were verified by mass spectrometry analysis. The chitosanase from both wild and mutant S. marcescens B742 was activated by sodium dodecyl sulfate (SDS), Tween 20, Tween 40, and Triton-100, and the protease and chitosanase were strongly inhibited by ethylenediaminetetraacetic acid (EDTA). These results suggested that S. marcescens B742 mutants can be used in the biological production of chitin through deproteinization of SSP.

  15. Severe Osteomyelitis and Septic Arthritis due to Serratia marcescens in an Immunocompetent Patient

    Directory of Open Access Journals (Sweden)

    Hiba Hadid

    2015-01-01

    Full Text Available Septic arthritis and osteomyelitis due to Serratia marcescens in immunocompetent patients without risk factors are extremely rare. Here, we report a case of septic arthritis and severe adjacent osteomyelitis of the tibia due to Serratia marcescens in a diabetic community-dweller patient. The patient had no contact with healthcare workers or facilities and had no chronic disease except for poorly controlled diabetes. Without predisposing risk factors, this type of infection is extremely rare, even in diabetics.

  16. [Serratia marcescens outbreak in Neonatal Intensive Care Unit: Guayaquil, Ecuador].

    Science.gov (United States)

    Soria, Claudia; Nieto, Nelson; Villacís, José E; Lainez, Sara; Cartelle, Mónica

    2016-12-01

    We report a Serratia marcescens outbreak occurred in the NICU of a pediatric hospital in Guayaquil, Ecuador. Nine cases of infection were detected, from which septicemia was developed in 55.5%. The index case was a newborn derived from another institution with septic arthritis caused by the outbreak strain. The infection rate was 17.6% and mortality rate was 33.3%. All isolates were resistant to aminoglycosides and susceptible to third generation cephalosporins and carbapenems. Clonality analysis by pulsed-field gel electrophoresis (PFGE) revealed the presence of two closely related clones confirming the horizontal spread. Measures were taken by the committee such as: strengthening the hand hygiene, patient hygiene and cohort studies of gastrointestinal colonization, which allowed the control of the outbreak.

  17. Nosocomial transmission of Serratia marcescens in a veterinary hospital due to contamination by benzalkonium chloride.

    Science.gov (United States)

    Fox, J G; Beaucage, C M; Folta, C A; Thornton, G W

    1981-01-01

    During a 1-year period, Serratia marcescens was isolated from 50% of all contaminate intravenous catheters from dogs and cats in a large veterinary hospital. S. marcescens was also isolated from respiratory tracts, genitourinary tracts, skin, and other sites in hospitalized animals. A total of 55% of the clinical isolates and 66% of the intravenous catheter isolates had the same API biochemical profile. The source of the S. marcescens was determined to be aqueous benzalkonium chloride (0.025%) sponge pots located in the intensive care unit, surgery rooms, and outpatient clinic areas of the hospital. Of the 11 S. marcescens isolates submitted to the Centers for Disease Control for serotyping (6 from aqueous benzalkonium chloride sponge pots, 5 from intravenous catheters), 8 were identified as serotype O10:H11. All S. marcescens isolates tested for antibiotic susceptibilities were multiply resistant; isolates were most frequently resistant to streptomycin, cephalothin, and ampicillin. This study demonstrates that improper use of disinfectants plays an important role in the nosocomial transmission of S. marcescens. PMID:7024303

  18. Antimicrobial effect and membrane-active mechanism of tea polyphenols against Serratia marcescens.

    Science.gov (United States)

    Yi, Shumin; Wang, Wei; Bai, Fengling; Zhu, Junli; Li, Jianrong; Li, Xuepeng; Xu, Yongxia; Sun, Tong; He, Yutang

    2014-02-01

    In this study, we investigated the antimicrobial effect of tea polyphenols (TP) against Serratia marcescens and examined the related mechanism. Morphology changes of S. marcescens were first observed by transmission electron microscopy after treatment with TP, which indicated that the primary inhibition action of TP was to damage the bacterial cell membranes. The permeability of the outer and inner membrane of S. marcescens dramatically increased after TP treatment, which caused severe disruption of cell membrane, followed by the release of small cellular molecules. Furthermore, a proteomics approach based on two-dimensional gel electrophoresis and MALDI-TOF/TOF MS analysis was used to study the difference of membrane protein expression in the control and TP treatment S. marcescens. The results showed that the expression of some metabolism enzymes and chaperones in TP-treated S. marcescens significantly increased compared to the untreated group, which might result in the metabolic disorder of this bacteria. Taken together, our results first demonstrated that TP had a significant growth inhibition effect on S. marcescens through cell membrane damage.

  19. Phosphate limitation induces the intergeneric inhibition of Pseudomonas aeruginosa by Serratia marcescens isolated from paper machines.

    Science.gov (United States)

    Kuo, Pei-An; Kuo, Chih-Horng; Lai, Yiu-Kay; Graumann, Peter L; Tu, Jenn

    2013-06-01

    Phosphate is an essential nutrient for heterotrophic bacteria, affecting bacterioplankton in aquatic ecosystems and bacteria in biofilms. However, the influence of phosphate limitation on bacterial competition and biofilm development in multispecies populations has received limited attention in existing studies. To address this issue, we isolated 13 adhesive bacteria from paper machine aggregates. Intergeneric inhibition of Pseudomonas aeruginosa WW5 by Serratia marcescens WW4 was identified under phosphate-limited conditions, but not in Luria-Bertani medium or M9 minimal medium. The viable numbers of the pure S. marcescens WW4 culture decreased over 3 days in the phosphate-limited medium; however, the mortality of S. marcescens WW4 was significantly reduced when it was co-cultured with P. aeruginosa WW5, which appeared to sustain the S. marcescens WW4 biofilm. In contrast, viable P. aeruginosa WW5 cells immediately declined in the phosphate-limited co-culture. To identify the genetic/inhibitory element(s) involved in this process, we inserted a mini-Tn5 mutant of S. marcescens WW4 that lacked inhibitory effect. The results showed that an endonuclease bacteriocin was involved in this intergeneric inhibition by S. marcescens WW4 under phosphate limitation. In conclusion, this study highlights the importance of nutrient limitation in bacterial interactions and provides a strong candidate gene for future functional characterisation.

  20. Necrotizing cellulitis with multiple abscesses on the leg caused by Serratia marcescens.

    Science.gov (United States)

    Hau, Estelle; Bouaziz, Jean-David; Lafaurie, Matthieu; Saussine, Anne; Masson, Vincent; Rausky, Jonathan; Bagot, Martine; Guibal, Fabien

    2016-03-01

    Serratia marcescens is an unusual cause of severe skin infection initially described in immunocompromised patients. We report a case of necrotizing cellulitis of the leg caused by S marcescens in a 68-year-old woman with diabetes mellitus and a history of chronic lymphoedema of the leg. We reviewed the literature and found 49 cases of severe skin infections from S marcescens that included 20 cases of necrotizing fasciitis (NF) as well as 29 cases of severe skin infections without NF (non-NF cases). Patients were immunocompromised in 59% to 70% of cases. The mortality rate was high in NF cases (60%) versus non-NF cases (3%). Surgery was required in 95% of NF cases and in 24% of non-NF cases. The other clinical manifestations of S marcescens skin infection reported in the literature included disseminated papular eruptions in patients infected with human immunodeficiency virus with folliculitis on the trunk. Serratia marcescens is naturally resistant to amoxicillin alone and amoxicillin associated with clavulanic acid. Broad-spectrum antibiotics are indicated to treat S marcescens skin infections, and surgery should be promptly considered in cases of severe skin infections if appropriate antibiotic therapy does not lead to rapid improvement.

  1. Application of the BIOLOG system for characterization of Serratia marcescens ss marcescens isolated from onsite wastewater technology (OSWT).

    Science.gov (United States)

    Chojniak, Joanna; Jałowiecki, Łukasz; Dorgeloh, Elmar; Hegedusova, Berta; Ejhed, Helene; Magnér, Jörgen; Płaza, Grażyna

    2015-01-01

    The scope of this study was to apply the Biolog system to identify and characterize a Serratia strain isolated from the surface of black plastic pieces which constitute the fluidized bed filter (onsite wastewater technology, OSWT). The preliminary isolation of the strain was done in the medium with tetracycline at a 16 mg/l concentration. To characterize the isolated strain, the following Biolog methods were applied: (1) EcoPlates microplates for evaluation of physiological profiling, (2) GEN III OmniLog® ID System for identification of the isolate, and (3) phenotypic microarrays (PM) technology for evaluation of sensitivity to antibiotics (PM11 and PM12). Results were recorded using the original OmniLog® software. The Serratia strain was identified as Serratia marcescens ss marcescens with similarity index 0.569. The same identification was obtained by the 16S rDNA analysis. PM analysis showed an enhancement of phenotype (resistance or growth) of this strain to 35 antibiotics. The loss of phenotype (sensitivity or non-growth) was observed only for 5 antibiotics: lomefloxacin (0.4 µg/ml), enoxacin (0.9 µg/ml), nalidixic acid (18.0 µg/ml), paromomycin (25.0 µg/ml) and novobiocin (1100 µg/ml). This study acknowledges that the methods proposed by the Biolog system allow correct and complete identification and characterization of the microbes isolated from different environments. Phenotypic microarrays could be successfully used as a new tool for identification of the multi-antibiotic resistance of bacteria and for determination of the minimal inhibition concentrations (MIC).

  2. Community-acquired Serratia marcescens spinal epidural abscess in a patient without risk factors: Case report and review.

    Science.gov (United States)

    Parkins, Michael D; Gregson, Daniel B

    2008-05-01

    Serratia marcescens has rarely been reported as an agent of invasive disease in patients presenting from the community. Furthermore, S marcescens is frequently opportunistic, affecting individuals with serious medical comorbidities including immune suppression and diabetes. A case of a community-acquired S marcescens spontaneous lumbar epidural abscess presenting as cauda equina syndrome is reported in a previously well 36-year-old man with no identifiable risk factors. To the authors' knowledge, this is the first report of invasive S marcescens causing disease in a patient with no medical comorbidities.

  3. Community-Acquired Serratia Marcescens Spinal Epidural Abscess in a Patient Without Risk Factors: Case Report and Review

    Directory of Open Access Journals (Sweden)

    Michael D Parkins

    2008-01-01

    Full Text Available Serratia marcescens has rarely been reported as an agent of invasive disease in patients presenting from the community. Furthermore, S marcescens is frequently opportunistic, affecting individuals with serious medical comorbidities including immune suppression and diabetes. A case of a community-acquired S marcescens spontaneous lumbar epidural abscess presenting as cauda equina syndrome is reported in a previously well 36-year-old man with no identifiable risk factors. To the authors’ knowledge, this is the first report of invasive S marcescens causing disease in a patient with no medical comorbidities.

  4. Antimicrobial susceptibilities and bacteriological characteristics of bovine Pseudomonas aeruginosa and Serratia marcescens isolates from mastitis.

    Science.gov (United States)

    Ohnishi, Mamoru; Sawada, Takuo; Hirose, Kazuhiko; Sato, Reiichiro; Hayashimoto, Mizuki; Hata, Eiji; Yonezawa, Chizuko; Kato, Hajime

    2011-12-29

    The presence of metallo-β-lactamase (MBL)-producing and multidrug-resistant Pseudomonas aeruginosa (MDRP) strains among bovine isolates of Gram-negative bacilli, and O-serotypes of bovine Serratia marcescens and P. aeruginosa isolates have been reported rarely. The aims of this study were to (1) elucidate antimicrobial susceptibilities and O-serotypes of P. aeruginosa and S. marcescens isolates from bovine mastitis and the presence of MBL-producers and MDRP strains among them and (2) evaluate their relationships to human isolates. We investigated the MICs of 24 antimicrobials and O-serotypes for 116 P. aeruginosa and 55 S. marcescens isolates in Japan, primarily in 2006. A total of 171 isolates exhibited high antimicrobial susceptibilities with the exception of a partial drug. P. aeruginosa isolates exhibited high susceptibilities of ≥ 95.7% to ciprofloxacin, imipenem, meropenem, piperacillin, ceftazidime, cefepime, cefoperazone/sulbactam, amikacin, tobramycin, and gentamicin; however, they exhibited a susceptibility of only 69.8% to aztreonam. They exhibited substantial resistances to ceftriaxone, enrofloxacin, cefotaxime, and moxalactam. S. marcescens isolates exhibited high susceptibilities of ≥ 90.9% to kanamycin, ceftiofur, sulfamethoxazole-trimethoprim, and the 15 aforementioned drugs, but exhibited resistance to minocycline. Neither MBL-producers nor MDRP strains were detected among the 171 strains. The dominant serotypes of P. aeruginosa isolates were OG, OA, OB, OI, OF, OE, and OK; those of S. marcescens isolates were O6 and O5. Every S. marcescens isolate was pigmented. These findings suggest that bovine P. aeruginosa and S. marcescens isolates differ from human isolates from both antibiogram and phenotypic perspectives, and could help to evaluate differences in bacteriological characteristics between bovine and human isolates.

  5. ManA is regulated by RssAB signaling and promotes motility in Serratia marcescens.

    Science.gov (United States)

    Soo, Po-Chi; Horng, Yu-Tze; Chang, Yung-Lin; Tsai, Wei-Wen; Jeng, Wen-Yih; Lu, Chia-Chen; Lai, Hsin-Chih

    2014-01-01

    Serratia marcescens swarms on 0.8% LB agar at 30 °C but not at 37 °C. To understand the molecular mechanism regulating Serratia swarming, transposon mutagenesis was performed to screen for mutants that swarmed at 37 °C. In one mutant, S. marcescens WW100, the transposon was inserted in the upstream region of manA, which encodes mannose-6-phosphate isomerase, a type I phosphomannose isomerase. The transcriptional and translational levels of manA were higher in S. marcescens WW100 than in the wild-type strain. S. marcescens WW100 produced more serrawettin W1 (biosurfactant) than the wild-type, as detected by thin-layer chromatography, to promote surface motility by reducing surface tension. Serratia swarming was previously shown to be negatively regulated by the RssA-RssB two-component system. An electrophoretic mobility shift assay (EMSA) indicated that phosphorylated RssB (the response regulator) binds upstream of the transposon insertion site and manA in S. marcescens WW100. Analysis by real-time RT-PCR (qRT-PCR) revealed that, compared to the wild-type level, manA mRNA was increased in the rssA deletion mutant. The results indicated that RssA-RssB signaling directly represses the expression of manA and that overexpression of manA increases the production of serrawettin for Serratia swarming at 37 °C.

  6. Identification of a Serratia marcescens virulence factor that promotes hemolymph bleeding in the silkworm, Bombyx mori.

    Science.gov (United States)

    Ishii, Kenichi; Adachi, Tatsuo; Hara, Takashi; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

    2014-03-01

    Injection of culture supernatant of Serratia marcescens, a Gram-negative bacterium pathogenic to a wide range of host animals including insects and mammals, into the hemolymph of silkworm (Bombyx mori) larvae led to continuous flow of the hemolymph (blood of insects) from the injection site. The amount of hemolymph lost within 60 min reached 15-20% of the total larval weight. Using a bioassay with live silkworms, we purified Serralysin, a metalloprotease that requires divalent cations for its activity, as the factor responsible for the promotion of hemolymph bleeding from the culture supernatant of S. marcescens. Recombinant protein also induced hemolymph bleeding in silkworms. Moreover, the culture supernatant of an S. marcescens disruption mutant of the ser gene showed attenuated ability to promote hemolymph bleeding. In addition, this bleeding-promoting activity of the S. marcescens culture supernatant was attenuated by disruption of the wecA gene, which is involved in the biosynthesis of the lipopolysaccharide O-antigen. These findings suggest that Serralysin metalloprotease contributes to the pathogenesis of S. marcescens by inhibiting wound healing, which leads to a massive loss of hemolymph from silkworm larvae.

  7. Multiple skin ulcers due to Serratia marcescens in a immunocompetent patient.

    Science.gov (United States)

    Carlesimo, M; Pennica, A; Muscianese, M; Bottoni, U; Abruzzese, C; Giubettini, M; Pranteda, G; Pranteda, G

    2014-06-01

    Serratia marcescens is a species of gram negative bacillus, classified as a member of the Enterobacteriaceae, mainly involved in opportunistic infections, particulary in the hospital environment. Cutaneous infections have rarely reported in literature and are predominantly observed in elderly or in immunocompromised patients. The clinical manifestations of skin infections include granulomatous lesions, necrotizing fasciitis, nodules, cellulitis, ulcers, dermal abscesses. Infections caused by S. marcescens may be difficult to treat because of resistance to a variety of antibiotics, including ampicillin and first and second generation cephalosporins. Aminoglycosides have good activity against S. marcescens, but resistant strains have also been described. We report a very intriguing case of S. marcescens infection, in an immunocompetent 18-year-old man, causing multiple rounded ulcers of varying sizes, along with few pustular lesions that both clinically and histopathologically mimic a pyoderma gangrenosum (PG). This is a non infectious neutrophilic skin disorder, characterized by painful and rapidly progressing skin ulceration. According to our experience, we would strongly recommend to perform cultures of multiple skin ulcers resembling PG, even in young healthy patients, to ensure correct diagnosis and treatment, since resistant to conventional antibiotics bacteria such as S. marcescens may be the cause of these lesions, like in the case here reported.

  8. RssAB-FlhDC-ShlBA as a major pathogenesis pathway in Serratia marcescens.

    Science.gov (United States)

    Lin, Chuan-Sheng; Horng, Jim-Tong; Yang, Chun-Hung; Tsai, Yu-Huan; Su, Lin-Hui; Wei, Chia-Fong; Chen, Chang-Chieh; Hsieh, Shang-Chen; Lu, Chia-Chen; Lai, Hsin-Chih

    2010-11-01

    Serratia marcescens has long been recognized as an important opportunistic pathogen, but the underlying pathogenesis mechanism is not completely clear. Here, we report a key pathogenesis pathway in S. marcescens comprising the RssAB two-component system and its downstream elements, FlhDC and the dominant virulence factor hemolysin ShlBA. Expression of shlBA is under the positive control of FlhDC, which is repressed by RssAB signaling. At 37°C, functional RssAB inhibits swarming, represses hemolysin production, and promotes S. marcescens biofilm formation. In comparison, when rssBA is deleted, S. marcescens displays aberrant multicellularity favoring motile swarming with unbridled hemolysin production. Cellular and animal infection models further demonstrate that loss of rssBA transforms this opportunistic pathogen into hypervirulent phenotypes, leading to extensive inflammatory responses coupled with destructive and systemic infection. Hemolysin production is essential in this context. Collectively, a major virulence regulatory pathway is identified in S. marcescens.

  9. Requirement for Serratia marcescens cytolysin in a murine model of hemorrhagic pneumonia.

    Science.gov (United States)

    González-Juarbe, Norberto; Mares, Chris A; Hinojosa, Cecilia A; Medina, Jorge L; Cantwell, Angelene; Dube, Peter H; Orihuela, Carlos J; Bergman, Molly A

    2015-02-01

    Serratia marcescens, a member of the carbapenem-resistant Enterobacteriaceae, is an important emerging pathogen that causes a wide variety of nosocomial infections, spreads rapidly within hospitals, and has a systemic mortality rate of ≤41%. Despite multiple clinical descriptions of S. marcescens nosocomial pneumonia, little is known regarding the mechanisms of bacterial pathogenesis and the host immune response. To address this gap, we developed an oropharyngeal aspiration model of lethal and sublethal S. marcescens pneumonia in BALB/c mice and extensively characterized the latter. Lethal challenge (>4.0 × 10(6) CFU) was characterized by fulminate hemorrhagic pneumonia with rapid loss of lung function and death. Mice challenged with a sublethal dose (marcescens strains that failed to cause profound weight loss, extended illness, hemorrhage, and prolonged lung pathology in mice. This study describes a model of S. marcescens pneumonia that mimics known clinical features of human illness, identifies neutrophils and the toxin ShlA as a key factors important for defense and infection, respectively, and provides a solid foundation for future studies of novel therapeutics for this important opportunistic pathogen.

  10. Serratia marcescens resistance profile and its susceptibility to photodynamic antimicrobial chemotherapy.

    Science.gov (United States)

    Parente, Ticiana Mont Alverne Lopes; Rebouças, Emanuela de Lima; Santos, Vitor Coutinho Vieira Dos; Barbosa, Francisco Cesar Barroso; Zanin, Iriana Carla Junqueira

    2016-06-01

    Some authors have reported the antimicrobial action of photodynamic antimicrobial chemotherapy (PACT) on bacteria related to nosocomial infections but there are few studies evaluating PACT on Serratia marcescens grown as planktonic cultures or as biofilms. The purpose of this study was to analyze the S. marcescens resistance profile and its susceptibility to PACT. Initially, 55 S. marcescens strains isolated from environmental, oral and extra-oral infections were tested by antimicrobial resistance to cefotaxime (CTX), imipenem (IPM), ciprofloxacin (CIP), tobramycin (TOB) and doxycycline (DOX) using E-test(®). Following, isolates grown as planktonic cultures or biofilms were submitted to PACT using the association of a light-emitting diode and toluidine blue (TBO). The E-test(®) results demonstrated intermediated sensitive strains to CTX, IMP, TOB, and DOX; and resistant strains to CTX, TOB, DOX and CIP. Also, CTX and IMP demonstrated variation when CLSI 2007 and CLSI 2015 were compared. Planktonic cultures and biofilms submitted to PACT demonstrated counts varying from 10(11) to 10(7) for planktonic cultures and 10(10) to 10(7) for biofilms. There were no statistical differences in the results when planktonic cultures and biofilms were compared. Increase in the profile of S. marcescens resistance was observed when CLSI 2007 and CLSI 2015 were compared. Also, IMP remains as the drug with lower rate of resistance. Additionally, both S. marcescens planktonic cultures and early biofilms are susceptible to PACT under tested conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Pathogenicity of Isolates of Serratia Marcescens towards Larvae of the Scarab Phyllophaga Blanchardi (Coleoptera)

    Science.gov (United States)

    Pineda-Castellanos, Mónica L.; Rodríguez-Segura, Zitlhally; Villalobos, Francisco J.; Hernández, Luciano; Lina, Laura; Nuñez-Valdez, M. Eugenia

    2015-01-01

    Serratia marcescens is a Gram negative bacterium (Enterobacteriaceae) often associated with infection of insects. In order to find pathogenic bacteria with the potential to control scarab larvae, several bacterial strains were isolated from the hemocoel of diseased Phyllophaga spp (Coleoptera:Scarabaeidae) larvae collected from cornfields in Mexico. Five isolates were identified as Serratia marcescens by 16S rRNA gene sequencing and biochemical tests. Oral and injection bioassays using healthy Phyllophaga blanchardi larvae fed with the S. marcescens isolates showed different degrees of antifeeding effect and mortality. No insecticidal activity was observed for Spodoptera frugiperda larvae (Lepidoptera: Noctuidae) by oral inoculation. S. marcescens (Sm81) cell-free culture supernatant caused significant antifeeding effect and mortality to P. blanchardi larvae by oral bioassay and also mortality by injection bioassay. Heat treated culture broths lost the ability to cause disease symptoms, suggesting the involvement of proteins in the toxic activity. A protein of 50.2 kDa was purified from the cell-free broth and showed insecticidal activity by injection bioassay towards P. blanchardi. Analysis of the insecticidal protein by tandem- mass spectrometry (LC-MS/MS) showed similarity to a Serralysin-like protein from S. marcescens spp. This insecticidal protein could have applications in agricultural biotechnology. PMID:25984910

  12. Effects of Dimerization of Serratia marcescens Endonuclease on Water Dynamics.

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chuanying; Beck, Brian W.; Krause, Kurt; Weksberg, Tiffany E.; Pettitt, Bernard M.

    2007-02-15

    The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. The dynamics and structure of Serratia marcescens endonuclease and its neighboring solvent are investigated by molecular dynamics (MD). Comparisons are made with structural and biochemical experiments. The dimer form is physiologic and functions more processively than the monomer. We previously found a channel formed by connected clusters of waters from the active site to the dimer interface. Here, we show that dimerization clearly changes correlations in the water structure and dynamics in the active site not seen in the monomer. Our results indicate that water at the active sites of the dimer is less affected compared with bulk solvent than in the monomer where it has much slower characteristic relaxation times. Given that water is a required participant in the reaction, this gives a clear advantage to dimerization in the absence of an apparent ability to use both active sites simultaneously.

  13. Severe necrotizing myocarditis caused by serratia marcescens infection in an axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Del-Pozo, J; Girling, S; Pizzi, R; Mancinelli, E; Else, R W

    2011-05-01

    This report provides the first account of the pathological changes associated with infection by Serratia marcescens in an adult male axolotl. The infection resulted in septicaemia with severe multifocal necrotizing myocarditis. The latter lesion evolved to cardiac rupture, haemopericardium and death resulting from cardiac tamponade. This animal was exposed to higher than usual temperatures (24-25 °C) 2 weeks before the onset of disease and this may have resulted in immunocompromise and opportunistic bacterial infection. S. marcescens was isolated from the coelomic and pericardial cavity. Both isolates were identical and were resistant to β-lactam antibiotics, but not to aminoglycosides or fluoroquinolones. The production of red prodigiosin pigment by the bacterium suggested an environmental origin. Overall, the clinical and histopathological presentation suggests that S. marcescens should be included in the list of aetiological agents of the 'red-leg'/bacterial dermatosepticaemia syndrome of amphibians.

  14. A case of pulmonary Serratia marcescens granuloma radiologically mimicking metastatic malignancy and tuberculosis infection.

    Science.gov (United States)

    Das, Joyutpal; Layton, Benjamin; Lamb, Harriet; Sinnott, Nicola; Leahy, Bernard C

    2015-11-01

    Serratia marcescens is a saprophytic gram-negative bacillus capable of causing a wide range of infections. A 57-year-old female was admitted to our hospital for four weeks with community acquired pneumonia. A chest x-ray, six weeks after discharge, demonstrated multiple, bilateral 'cannon ball'-like opacities and mediastinal lymphadenopathy which were highly suspicious of disseminated malignancy or tuberculosis. The only symptom that this patient had was a productive cough. She had multiple commodities, but no specific immunodeficiency disorder. Interestingly, her sputum and bronchial washing samples grew S. marcescens. The computed tomography-guided lung biopsy demonstrated necrotic granulomatous changes. There was no pathological evidence of tuberculosis or fungal infection, malignancy or vasculitis. There are only a handful of reported cases of Serratia granulomas. Thus, we are reporting a rare instance of pulmonary Serratia marcescens granuloma radiologically mimicking metastatic malignancy and tuberculosis infection.

  15. Inhibition of Serratia marcescens Smj-11 biofilm formation by Alcaligenes faecalis STN17 crude extract

    Energy Technology Data Exchange (ETDEWEB)

    Lutfi, Zainal; Ahmad, Asmat [School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Usup, Gires [School of Environmental and Natural Resources Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2014-09-03

    Serratia marcescens biofilms are formed when they are bound to surfaces in aqueous environments. S. marcescens utilizes N-acylhomoserine lactone (AHL) as its quorum sensing signal molecule. The accumulation of AHL indicates the bacteria to produce matrices to form biofilms. Prodigiosin (2-methyl-3-pentyl-6-methoxyprodigiosin), which causes red pigmentation in the colonies, are also produced when the AHL reaches a certain threshold. The Alcaligenes faecalis STN17 crude extract is believed to inhibit quorum sensing in the S. marcescens Smj-11 and, thus, impedes its biofilm formation ability. A. faecalis STN17 was grown in marine broth, and ethyl acetate extraction was carried out. The crude compound of A. faecalis STN17 was diluted at high concentration (0.2-6.4 mg/mL) and was taken to confirm anti-biofilm activity through the crystal violet method in 96-wells plate. Then, the crude extract underwent purification using simple solvents partitioning test to discern the respective compounds that had the anti-biofilm activity under the crystal violet method. The crystal violet test showed that the crude did have anti-biofilm activity on S. marcescens Smj-11, but did not kill the cells. This finding signifies that the suppression of biofilm formation in S. marcescens by A. faecalis STN17 has a strong correlation. The partitioning test showed that A. faecalis STN17 crude extract has several compounds and only the compound(s) in chloroform showed activities. In conclusion, the crude extract of A. faecalis STN17 has the ability to inhibit S. marcescens Smj-11 biofilm formation.

  16. Severe Acute Infection Due to Serratia marcescens Causing Respiratory Distress in An Immunocompetent Adult.

    Science.gov (United States)

    Ruiz-Sada, Pablo; Escalante, Mikel; Lizarralde, Eva

    2016-01-01

    The role of Serratia marcescens changed from a harmless saprophytic microorganism to an important opportunistic human pathogen. It often causes nosocomial device-associated outbreaks and rarely serious invasive community acquired infections. We present a case of a community-acquired Serratia marcescens bacteremia leading to Respiratory Distress Syndrome in a previously healthy 51-year-old man without identifiable risk factors. Full recovery was achieved with solely medical treatment and observation in ICU during three days. To our knowledge it is an extremely uncommon presentation and just few cases have been previously reported in the literature.

  17. Compatible results obtained from biotyping and serotyping in Serratia marcescens.

    Science.gov (United States)

    Grimont, P A; Grimont, F; Le Minor, S; Davis, B; Pigache, F

    1979-10-01

    The correspondence between complete serotype and biotype (P.A.D. Grimont and F. Grimont, J. Clin. Microbiol. 8:73-83, 1978) of 474 Serratia marcescens strains was studied. Of 127 serotypes, 70 were represented by two or more strains of the same serotype belonged to one biotype. However, for 91% of serotypes, strains of the same serotype belonged to one biogroup--i.e., a group of closely related biotypes. Biogroups are A1 (A1a, A1b); A2/6 (A2a, A2b, A6a, A6b); A3 (A3a, A3b, A3c, A3d); A4 (A4a, A4b); A5/8 (A5, A8a, A8b, A8c); and TCT (TCT, TT). Only two serotypes were composed of a mixture of pigmented and nonpigmented biogroups. Pigmented biogroups (A1 and A2/6) were otherwise differentiated from nonpigmented biogroups (A3, A4, A5/8, and TCT) by serotyping. Some biogroups preferentially occurred in some O serogroups: A4 in 01; A2/6 in O6, O8, and O14; and A3 in O9, O12, and O15. Three H serogroups were found to be biochemically homogeneous: H1, H7, and H20 were respectively and uniquely composed of biogroups A4, TCT, and A3. A square matrix of O versus H serogroups, with the corresponding biogroup for each O X H combination, was used for comparisons between O groups and between H groups. Identical patterns of biogroups were shown by serogroups O6, O8, and O14. Taxonomical, ecological, and practical consequences of these findings are discussed.

  18. The response of Serratia marcescens JG to environmental changes by quorum sensing system.

    Science.gov (United States)

    Sun, Shu-Jing; Liu, Hui-Jun; Weng, Cai-Hong; Lai, Chun-Fen; Ai, Liu-Ying; Liu, Yu-Chen; Zhu, Hu

    2016-08-01

    Many bacterial cells are known to regulate their cooperative behaviors and physiological processes through a molecular mechanism called quorum sensing. Quorum sensing in Serratia marcescens JG is mediated by the synthesis of autoinducer 2 (AI-2) which is a furanosyl borate diester. In this study, the response of quorum sensing in S. marcescens JG to environment changes such as the initial pH, carbon sources and boracic acid was investigated by a bioreporter and real-time PCR analysis. The results show that glucose can affect AI-2 synthesis to the greatest extent, and 2.0 % glucose can stimulate S. marcescens JG to produce more AI-2, with a 3.5-fold increase in activity compared with control culture. Furthermore, the response of quorum sensing to changes in glucose concentration was performed by changing the amount of luxS RNA transcripts. A maximum of luxS transcription appeared during the exponential growth phase when the glucose concentration was 20.0 g/L. AI-2 production was also slightly impacted by the low initial pH. It is significant for us that the addition of boracic acid at microdosage (0.1-0.2 g/L) can also induce AI-2 synthesis, which probably demonstrated the feasible fact that the 4,5-dihydroxy-2, 3-pentanedione cyclizes by the addition of borate and the loss of water, is hydrated and is converted to the final AI-2 in S. marcescens JG.

  19. Phenotypic Diversification and Adaptation of Serratia marcescens MG1 Biofilm-Derived Morphotypes

    DEFF Research Database (Denmark)

    Koh, Kai Shyang; Lam, Kin Wai; Alhede, Morten

    2007-01-01

    We report here the characterization of dispersal variants from microcolony-type biofilms of Serratia marcescens MG1. Biofilm formation proceeds through a reproducible process of attachment, aggregation, microcolony development, hollow colony formation, and dispersal. From the time when hollow col...

  20. HasB, the Serratia marcescens TonB paralog, is specific to HasR.

    Science.gov (United States)

    Benevides-Matos, Najla; Wandersman, Cécile; Biville, Francis

    2008-01-01

    Serratia marcescens possesses two functional TonB paralogs, TonB(Sm) and HasB, for energizing TonB-dependent transport receptors (TBDT). Previous work had shown that HasB is specific to heme uptake in the natural host and in Escherichia coli expressing the S. marcescens TBDT receptor HasR, whereas the S. marcescens TonB and E. coli TonB proteins function equally well with various TBDT receptors for heme and siderophores. This has raised the question of the target of this specificity. HasB could be specific either to heme TBDT receptors or only to HasR. To resolve this question, we have cloned in E. coli another S. marcescens heme receptor, HemR, and we show here that this receptor is TonB dependent and does not work with HasB. This demonstrates that HasB is not dedicated to heme TBDT receptors but rather forms a specific pair with HasR. This is the first reported case of a specific TonB protein working with only one TBDT receptor in one given species. We discuss the occurrence, possible molecular mechanisms, and selective advantages of such dedicated TonB paralogs.

  1. Enhanced production of prodigiosin by Serratia marcescens MO-1 using ram horn peptone

    Directory of Open Access Journals (Sweden)

    Esabi Basaran Kurbanoglu

    2015-06-01

    Full Text Available This work addresses the production of prodigiosin from ram horn peptone (RHP using MO-1, a local isolate in submerged culture. First, a novel gram-negative and rod-shaped bacterial strain, MO-1, was isolated from the body of the grasshopper (Poecilemon tauricola Ramme 1951, which was collected from pesticide-contaminated fields. Sequence analysis of 16S rDNA classified the microbe as Serratia marcescens. The substrate utilization potential (BIOLOG and fatty acid methyl ester profile (FAME of S. marcescens were also determined. The effect of RHP on the production of prodigiosin by S. marcescens MO-1 was investigated, and the results showed that RHP supplementation promoted the growth of MO-1 and increased the production of prodigiosin. A concentration of 0.4% (w/v RHP resulted in the greatest yield of prodigiosin (277.74 mg/L after 48 h when mannitol was used as the sole source of carbon. The pigment yield was also influenced by the types of carbon sources and peptones. As a result, RHP was demonstrated to be a suitable substrate for prodigiosin production. These results revealed that prodigiosin could be produced efficiently by S. marcescens using RHP.

  2. Hand washing soap as a source of neonatal Serratia marcescens outbreak.

    Science.gov (United States)

    Rabier, V; Bataillon, S; Jolivet-Gougeon, A; Chapplain, J-M; Beuchée, A; Bétrémieux, P

    2008-10-01

    To describe an outbreak of Serratia marcescens infections in a neonatal intensive care unit (NICU) and to report investigations and interventions having led to the cessation of the outbreak. Observational study of microbiological and epidemiological investigations realised during a S. marcescens outbreak between March and October 2006. Nine cases were observed in a 5 months period. A Serratia outbreak was therefore identified, and all the strains were compared by pulsed-field gel electrophoresis (PFGE). Data from medical notes were gathered retrospectively. Environmental samples were gathered prospectively. Four infants were colonized and five infants were infected by S. marcescens. PFGE revealed that three different strains were present. Seven of the nine babies were infected by only one of these strains. This same strain was found in a nonantimicrobial soap bottle (NAS) that could be the source of contamination. It is the first time that S. marcescens is found in a NAS during a neonatal nosocomial outbreak. Molecular analysis is a method of choice to compare different strains. Identification and elimination of the nosocomial source and adherence to the infection control policies are essential to succeed in the containment of a nosocomial epidemic.

  3. Prodigiosin production by Serratia marcescens UCP 1549 using renewable-resources as a low cost substrate.

    Science.gov (United States)

    de Araújo, Helvia W Casullo; Fukushima, K; Takaki, Galba M Campos

    2010-10-08

    A new strain of Serratia marcescens UCP1459 isolated from a semi-arid soil produced the natural red pigment prodigiosin, characterized by an uncommon pyrrolylpyrromethane skeleton. Prodigiosin is a promising drug due to its reported antifungal, immunosuppressive and anti-proliferative activities. The objective of this work was to indentify a suitable medium to simultaneously enhance S. marcescens growth and pigment production using renewable resources obtained from industrial wastes. S. marcescens produced the highest level of prodigiosin (49.5 g/L) at 48 h of cultivation using 6% "manipueira" (cassava wastewater) supplemented with mannitol (2%) at pH 7 and 28 °C. Carbohydrates in "manipueira" and mannitol play a role in the enhanced cell growth and prodigiosin production. The purified pigment extracted from the biomass was analyzed by mass spectrophotometry and showed the expected molecular weight of 324 Da corresponding to prodigiosin. In conclusion, we have successfully designed a new, economically feasible medium supporting enhanced S. marcescens growth and a high yield production of prodigiosin.

  4. Draft Genome Sequences of Pandrug-Resistant Serratia marcescens Clinical Isolates Harboring blaNDM-1

    Science.gov (United States)

    Yao, Yancheng; Falgenhauer, Linda; Kempf, Volkhard A. J.; Hogardt, Michael; Göttig, Stephan; Imirzalioglu, Can

    2017-01-01

    ABSTRACT The draft genome sequences of two clonal, pandrug-resistant Serratia marcescens clinical isolates were determined. The resistance phenotype was plasmid driven, as 14 of 17 resistance genes were present on large IncFIB(K), IncHI2, and IncA/C2 plasmids indicating a large pool of transmissible antibiotic resistance genes. PMID:28104656

  5. Oxidation of dibenzothiophene (DBT by Serratia marcescens UCP 1549 formed biphenyl as final product

    Directory of Open Access Journals (Sweden)

    de Araújo Hélvia W

    2012-05-01

    Full Text Available Abstract Background The desulphurization of dibenzothiophene (DBT, a recalcitrant thiophenic fossil fuel component by Serratia marcescens (UCP 1549 in order for reducing the Sulphur content was investigated. The Study was carried out establishing the growth profile using Luria Bertani medium to different concentrations of DBT during 120 hours at 28°C, and orbital Shaker at 150 rpm. Results The results indicated that concentrations of DBT 0.5, 1.0 and 2.0 mM do not affected the growth of the bacterium. The DBT showed similar Minimum Inhibitory Concentration (MIC and Minimum Bactericidal Concentration (MCB (3.68 mM. The desulphurization of DBT by S. marcescens was used with 96 hours of growth on 2 mM of DBT, and was determined by gas chromatography (GC and GC-mass spectrometry. In order to study the desulphurization process by S. marcescens was observed the presence of a sulfur-free product at 16 hours of cultivation. Conclusions The data suggests the use of metabolic pathway “4S” by S. marcescens (UCP 1549 and formed biphenyl. The microbial desulphurization process by Serratia can be suggest significant reducing sulphur content in DBT, and showed promising potential for reduction of the sulfur content in diesel oil.

  6. Toxicity evaluation of prodigiosin from Serratia marcescens in a Caenorhabditis elegans model

    Science.gov (United States)

    Seah, Siew-Wei; Nathan, Sheila; Wan, Kiew-Lian

    2016-11-01

    Serratia marcescens produces several secondary metabolites, including a red antimicrobial pigment, prodigiosin. There is considerable interest in prodigiosin and its derivatives due to their anticancer and immunosuppressive properties. Prodigiosin has also become the main choice of red dye in textiles. As prodigiosin has potentially high commercial value, there is a demand to develop high-throughput and cost-effective bioprocesses for prodigiosin production. However little is still known about its toxicity. This study was carried out to investigate the toxicity effect of prodigiosin. To determine if prodigiosin was potentially toxic to eukaryotic systems, the S. marcescens ATCC 274 wild type (Sma 274) and the non-prodigiosin producer S. marcescens Bizio WF mutant ATCC 29635 (WF mutant) were grown under the optimised conditions for prodigiosin production and fed to the nematode Caenorhabditis elegans. The mean time to death (TDmean) for Sma 274-infected worms assayed on agar was 112.6 hours while the WF mutant culture had a TDmean of 104.4 hours. However, the nematode killing kinetics were not significantly different between the prodigiosin-producing and non-producing S. marcescens strains (p>0.05). In lieu of its non-toxic property, prodigiosin has the potential to be developed for safe therapeutic applications and as a safe environmental friendly bio-dye.

  7. Production of vanillic acid from vanillin by resting cells of Serratia marcescens.

    OpenAIRE

    Perestelo, F.; Dalcón, M A; de la Fuente, G.

    1989-01-01

    Resting-cell suspensions of Serratia marcescens were able to convert, quantitatively, 0.3% vanillin to vanillic acid. The vanillic acid-producing activity reached a maximum after 28 h of incubation with 0.01% vanillin as an inducer.

  8. Enhanced production of prodigiosin by Serratia marcescens MO-1 using ram horn peptone.

    Science.gov (United States)

    Kurbanoglu, Esabi Basaran; Ozdal, Murat; Ozdal, Ozlem Gur; Algur, Omer Faruk

    2015-06-01

    This work addresses the production of prodigiosin from ram horn peptone (RHP) using MO-1, a local isolate in submerged culture. First, a novel gram-negative and rod-shaped bacterial strain, MO-1, was isolated from the body of the grasshopper (Poecilemon tauricola Ramme 1951), which was collected from pesticide-contaminated fields. Sequence analysis of 16S rDNA classified the microbe as Serratia marcescens. The substrate utilization potential (BIOLOG) and fatty acid methyl ester profile (FAME) of S. marcescens were also determined. The effect of RHP on the production of prodigiosin by S. marcescens MO-1 was investigated, and the results showed that RHP supplementation promoted the growth of MO-1 and increased the production of prodigiosin. A concentration of 0.4% (w/v) RHP resulted in the greatest yield of prodigiosin (277.74 mg/L) after 48 h when mannitol was used as the sole source of carbon. The pigment yield was also influenced by the types of carbon sources and peptones. As a result, RHP was demonstrated to be a suitable substrate for prodigiosin production. These results revealed that prodigiosin could be produced efficiently by S. marcescens using RHP.

  9. Detection of cytotoxic activity on Vero cells in clinical isolates of Serratia marcescens

    Directory of Open Access Journals (Sweden)

    G.V. Carbonell

    1997-11-01

    Full Text Available Cytotoxin production was studied in 60 Serratia marcescens strains isolated from hospitalized patients. Association of cytotoxic activity with serotype, source of isolation and presence of plasmids was also evaluated. Thirteen of the 60 S. marcescens strains produced a cytotoxic effect on Vero cells. These strains were isolated from distinct clinical sources and classified into seven different serotypes (O1:H7; O4:NM; O10:NT; O19:NM; O6,14:H4; O6,14:NM and O6,14:H1. No relationship was observed between cytotoxic activity and clinical source or serotypes of the strains. Plasmids from five cytotoxin-producing S. marcescens strains were transferred to E. coli K12/711. The transconjugants did not exhibit cytotoxicity, indicating that the cytotoxic effect is not plasmid-mediated among these strains. Although a cytotoxic activity was demonstrated in filtrates of some S. marcescens strains, further studies should be performed to assess the role of this toxin in pathogenesis

  10. CdTe quantum dots as a novel biosensor for Serratia marcescens and Lipopolysaccharide.

    Science.gov (United States)

    Ebrahim, Sh; Reda, M; Hussien, A; Zayed, D

    2015-01-01

    The main objective of this work is to synthesize CdTe quantum dots (QDs) conjugated with Concanavalin A (Con A) as a novel biosensor to be selective and specific for the detection of Lipopolysaccharide (LPS). In addition, the conjugated CdTe QDs-Con A was used as fluorescence labels to capture Serratia marcescens bacteria through the recognition between CdTe QDs-Con A and LPS of S. marcescens. The appearance of the lattice plans in the high resolution transmission electron photograph indicated a high crystalline with an average size of 4-5 nm for the CdTe QDs. The results showed that the relative fluorescence intensity of CdTe QDs-Con A decreased linearly with LPS concentration in the range from 10 to 90 fg/mL and with correlation coefficient (R(2)) equal to 0.9713. LPS surrounding the S. marcescens bacteria was bound to the CdTe QDs-Con A and leads to quenching of PL intensity. It was found that a good linear relationship between the relative PL intensity and the logarithmic of cell population of S. marcescens in range from 1×10 to 1×10(6) CFU/mL at pH 7 with R(2) of 0.952 was established.

  11. In vitro synergistic effects of fisetin and norfloxacin against aquatic isolates of Serratia marcescens.

    Science.gov (United States)

    Dong, Jing; Ruan, Jing; Xu, Ning; Yang, Yibin; Ai, Xiaohui

    2016-01-01

    Serratia marcescens is a common pathogenic bacterium that can cause infections in both humans and animals. It can cause a range of diseases, from slight wound infections to life-threatening bacteraemia and pneumonia. The emergence of antimicrobial resistance has limited the treatment of the diseases caused by the bacterium to a great extent. Consequently, there is an urgent need to develop novel antimicrobial strategies against this pathogen. Synergistic strategy is a new approach to treat the infections caused by drug-resistant bacteria. In this paper, we isolated and identified the first multi-resistant pathogenic Serratia marcescens strain from diseased soft-shelled turtles (Pelodiscus sinensis) in China. We then performed a checkerboard assay; the results showed that out of 10 tested natural products fisetin had synergistic effects against S. marcescens when combined with norfloxacin. The time-kill curve assay further confirmed the results of the checkerboard assay. We found that this novel synergistic effect could significantly reduce the dosage of norfloxacin against S. marcescens. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Interference of quorum sensing in urinary pathogen Serratia marcescens by Anethum graveolens.

    Science.gov (United States)

    Salini, Ramesh; Pandian, Shunmugiah Karutha

    2015-08-01

    Serratia marcescens is an opportunistic turned obligate pathogen frequently associated with urinary tract infections (UTI) and are multidrug resistant at most instances. Quorum sensing (QS) system, a population-dependent global regulatory system, controls the pathogenesis machinery of S. marcescens as it does in other pathogens. In the present study, methanol extract of a common herb and spice, Anethum graveolens (AGME) was assessed for its anti-QS potential against the clinical isolate of S. marcescens. AGME notably reduced the biofilm formation and QS-dependent virulence factors production in a concentration-dependent manner (64-1024 μg mL(-1)). The light and confocal microscopic images clearly evidenced the antibiofilm activity of AGME (256 μg mL(-1)) at its minimal biofilm inhibitory concentration. Besides, in support of biochemical assays, the expression analysis of QS-regulated genes fimC, bsmA and flhD which are crucial for initial adhesion and motility confirmed their downregulation upon exposure to AGME. LC-MS analysis of AGME revealed 3-O-methyl ellagic acid (3-O-ME) as one of its active principles having nearly similar antibiofilm activity and a reduced inhibition of prodigiosin (27%) and protease (15%) compared to AGME [prodigiosin (47%) and protease (50%)]. UFLC analysis revealed that 0.355 mg g(-1) of 3-O-ME was present in the AGME. AGME and the 3-O-ME significantly interfered the QS system of a QS model strain S. marcescens MG1 and its mutant S. marcescens MG44 which in turn corroborates the anti-QS mechanism of AGME.

  13. Carbon-Starvation Induces Cross-Resistance to Thermal, Acid, and Oxidative Stress in Serratia marcescens

    Directory of Open Access Journals (Sweden)

    Joseph R. Pittman

    2015-10-01

    Full Text Available The broad host-range pathogen Serratia marcescens survives in diverse host and non-host environments, often enduring conditions in which the concentration of essential nutrients is growth-limiting. In such environments, carbon and energy source starvation (carbon-starvation is one of the most common forms of stress encountered by S. marcescens. Related members of the family Enterobacteriaceae are known to undergo substantial changes in gene expression and physiology in response to the specific stress of carbon-starvation, enabling non-spore-forming cells to survive periods of prolonged starvation and exposure to other forms of stress (i.e., starvation-induced cross-resistance. To determine if carbon-starvation also results in elevated levels of cross-resistance in S. marcescens, both log-phase and carbon-starved cultures, depleted of glucose before the onset of high cell-density stationary-phase, were grown in minimal media at either 30 °C or 37 °C and were then challenged for resistance to high temperature (50 °C, low pH (pH 2.8, and oxidative stress (15 mM H2O2. In general, carbon-starved cells exhibited a higher level of resistance to thermal stress, acid stress, and oxidative stress compared to log-phase cells. The extent of carbon-starvation-induced cross-resistance was dependent on incubation temperature and on the particular strain of S. marcescens. In addition, strain- and temperature-dependent variations in long-term starvation survival were also observed. The enhanced stress-resistance of starved S. marcescens cells could be an important factor in their survival and persistence in many non-host environments and within certain host microenvironments where the availability of carbon sources is suboptimal for growth.

  14. Serratia marcescens induces apoptotic cell death in host immune cells via a lipopolysaccharide- and flagella-dependent mechanism.

    Science.gov (United States)

    Ishii, Kenichi; Adachi, Tatsuo; Imamura, Katsutoshi; Takano, Shinya; Usui, Kimihito; Suzuki, Kazushi; Hamamoto, Hiroshi; Watanabe, Takeshi; Sekimizu, Kazuhisa

    2012-10-19

    Injection of Serratia marcescens into the blood (hemolymph) of the silkworm, Bombyx mori, induced the activation of c-Jun NH(2)-terminal kinase (JNK), followed by caspase activation and apoptosis of blood cells (hemocytes). This process impaired the innate immune response in which pathogen cell wall components, such as glucan, stimulate hemocytes, leading to the activation of insect cytokine paralytic peptide. S. marcescens induced apoptotic cell death of silkworm hemocytes and mouse peritoneal macrophages in vitro. We searched for S. marcescens transposon mutants with attenuated ability to induce apoptosis of silkworm hemocytes. Among the genes identified, disruption mutants of wecA (a gene involved in lipopolysaccharide O-antigen synthesis), and flhD and fliR (essential genes in flagella synthesis) showed reduced motility and impaired induction of mouse macrophage cell death. These findings suggest that S. marcescens induces apoptosis of host immune cells via lipopolysaccharide- and flagella-dependent motility, leading to the suppression of host innate immunity.

  15. [Examination of metallo-beta-lactamase-producing different types of Serratia marcescens detected in the same patient].

    Science.gov (United States)

    Takamitsu, Ito; Fukui, Yasuo; Ono, Noriaki; Ikeda, Fumiaki; Kanayama, Akiko; Kobayashi, Intetsu

    2013-03-01

    Metallo-beta-lactamase (MBL) producing Serratia marcescens isolate was recovered from a study patient in September, 2007 in whom MBL non-producing S. marcescens had been isolated 2 months previously. Two S. marcescens isolates recovered from the study patient showed the same pulsed-field gel electrophoresis (PFGE) pattern. Seven S. marcescens isolates were recovered from other patients in our hospital during August, 2007 and November, 2007. Five of the seven isolates produced MBL. All of the MBL-producing isolates showed the same PFGE pattern and harbored plasmids of the same size and bla(IMP) genes. The bla(IMP) genes were easily transferred to Escherichia coli DH5alpha by transformation of a plasmid purified from the MBL-producing isolate. Those transformation experiments suggested that bla(IMP) genes were encoded by the plasmid. From these observations, it was speculated that the MBL non-producing S. marcescens isolate recovered from the study patient had acquired the plasmid which encoded bla(IMP) genes and a monoclone of MBL-producing S. marcescens spread horizontally in our hospital.

  16. Risk Assessment for the Spread of Serratia marcescens Within Dental-Unit Waterline Systems Using Vermamoeba vermiformis.

    Science.gov (United States)

    Lal, Sham; Singhrao, Sim K; Achilles-Day, Undine E M; Morton, L H Glyn; Pearce, Mark; Crean, StJohn

    2015-10-01

    Vermamoeba vermiformis is associated with the biofilm ecology of dental-unit waterlines (DUWLs). This study investigated whether V. vermiformis is able to act as a vector for potentially pathogenic bacteria and so aid their dispersal within DUWL systems. Clinical dental water was initially examined for Legionella species by inoculating it onto Legionella selective-medium plates. The molecular identity/profile of the glassy colonies obtained indicated none of these isolates were Legionella species. During this work bacterial colonies were identified as a non-pigmented Serratia marcescens. As the water was from a clinical DUWL which had been treated with Alpron™, this prompted the question as to whether S. marcescens had developed resistance to the biocide. Exposure to Alpron™ indicated that this dental biocide was effective, under laboratory conditions, against S. marcescens at up to 1 × 10(8) colony forming units/millilitre (cfu/ml). V. vermiformis was cultured for 8 weeks on cells of S. marcescens and Escherichia coli. Subsequent electron microscopy showed that V. vermiformis grew equally well on S. marcescens and E. coli (P = 0.0001). Failure to detect the presence of S. marcescens within the encysted amoebae suggests that V. vermiformis is unlikely to act as a vector supporting the growth of this newly isolated, nosocomial bacterium.

  17. Epidemic septic arthritis caused by Serratia marcescens and associated with a benzalkonium chloride antiseptic.

    Science.gov (United States)

    Nakashima, A K; McCarthy, M A; Martone, W J; Anderson, R L

    1987-01-01

    During a 6-week period, 10 patients were admitted to a hospital for treatment of knee or shoulder joint infections due to Serratia species. Isolates from eight patients were identified as Serratia marcescens with identical biochemical characteristics and antibiotic susceptibility patterns. Before the onset of infections, all patients had been treated by two orthopedic surgeons who shared an office. Studies revealed that infections were associated with previous joint injections (P = 4.44 X 10(-5] of methylprednisolone and lidocaine. Environmental cultures revealed that a canister of cotton balls soaked in aqueous benzalkonium chloride and two multiple-dose vials of methylprednisolone previously used by office personnel were contaminated with the epidemic strain of S. marcescens. The canister may have served as a potential reservoir for contamination of sterile solutions and equipment used for joint injections, of skin at the injection site, and of hands of personnel. No further cases occurred after the use of aqueous benzalkonium chloride was discontinued. PMID:3298308

  18. [Outbreak due to Serratia marcescens associated with intrinsic contamination of aqueous chlorhexidine].

    Science.gov (United States)

    Hervé, Beatrice; Chomali, May; Gutiérrez, Cecilia; Luna, Mariana; Rivas, Jeannette; Blamey, Rodrigo; Espinoza, Ricardo; Izquierdo, Giannina; Cabezas, Catalina; Alvarez, Claudia; de la Fuente, Sebastián

    2015-10-01

    Serratia marcescens is a widely distributed gram-negative rod, often associated to nosocomial infections. Some outbreaks linked to contaminated antiseptic solutions have been reported. In this study we report a nosocomial outbreak of surgical site infection and catheter insertion site infection due to S. marcescens. 33 patients with positive cultures were studied after an index case was identified. Epidemiological, microbiological and molecular analysis demostrated an intrinsic contamination of alcohol free chlorhexidine solution as causal factor. Positive cultures were associated with 13 clinical infections, 9 colonized patients, 6 pseudobacteremia episodes and 5 patients without documented exposure. Hospital and national recall of contaminated chlorhexidine solution was performed after this study. Intrinsic contamination of antiseptic solutions is an infrequent cause of nosocomial infections with major epidemiological relevance.

  19. KPC-PRODUCING Serratia marcescens IN A HOME-CARE PATIENT FROM RECIFE, BRAZIL.

    Science.gov (United States)

    Margate, Emmily; Magalhães, Vera; Fehlberg, Lorena Cristina Corrêa; Gales, Ana Cristina; Lopes, Ana Catarina Souza

    2015-01-01

    In this brief communication we describe the occurrence of a KPC-producing Serratia marcescens isolate in a home-care patient from Recife, Brazil. The blaKPC, blaSPM, blaIMP, blaVIM, blaOXA, blaCTX-M, blaSHV, blaTEM and blaGES genes were investigated by Polymerase Chain Reaction (PCR) and DNA sequencing. The isolate was positive for blaKPC-2 and blaTEM-1 and was resistant to aztreonam, cefepime, cefotaxime, imipenem, meropenem, gentamicin, ciprofloxacin and cefazidime, and susceptible only to amikacin, tigecycline and gatifloxacin. This is the first report in Brazil of KPC-producing S. marcescens clinical isolate outside of a hospital environment. Caregivers should be alert for the presence of this isolate in the community setting.

  20. Epidemiological markers of Serratia marcescens isolates causing nosocomial infections in Spain (1981-1991).

    Science.gov (United States)

    Boquete, T; Vindel, A; Martin-Bourgon, C; Azañedo, L; Sáez-Nieto, J A

    1996-12-01

    The distribution of epidemiological markers (serotyping and phage-typing) of Serratia marcescens isolates from nosocomial episodes (63 nosocomial cutbreaks with 475 isolates, and 1208 sporadic cases) received in our laboratory during the period 1981-1991 was studied. The records for 1683 isolates from Spanish hospitals have been analyzed. In relation with the sporadic cases, the predominant types were serotype O6 (13.4%) and serotype O14 (11.4%); polyagglutinable strains accounted for 15.6%; in outbreaks, type O14 is clearly predominant (27.4%). Phage-typing was a good secondary marker, with a 87.9% of typability; the number of lytic patterns was very high, extended patterns (six or more phages) being the most frequent. We have studied the characteristics of S. marcescens isolates causing infections in the nosocomial environment in Spain.

  1. The role of outer membrane in Serratia marcescens intrinsic resistance to antibiotics.

    Science.gov (United States)

    Sánchez, L; Ruiz, N; Leranoz, S; Viñas, M; Puig, M

    1997-09-01

    Three different porins from Serratia marcescens were described. They were named Omp1, Omp2 and Omp3 and their molecular weights were 42, 40 and 39 kDa respectively. Omp2 and Omp3 showed osmoregulation and thermoregulation in a similar way to OmpC and OmpF of Escherichia coli. Permeability coefficients of the outer membrane of this species were calculated following the Zimmermann and Rosselet method. P values were similar to those obtained in Escherichia coli, which suggests that the chromosomal beta-lactamase would play a major role in the resistance of Serratia marcescens to beta-lactam antibiotics. Both MIC values and permeabilities were modified by salycilates and acetylsalycilate. Synergism between the outer membrane and the beta-lactamase was also evaluated. When bacteria grew in the presence of a beta-lactam in the medium, the beta-lactamase accounted for most of the resistance.

  2. An outbreak of multidrug-resistant Serratia marcescens: The importance of continuous monitoring of nosocomial infections

    Directory of Open Access Journals (Sweden)

    Maida Šiširak

    2013-05-01

    Full Text Available Objectives. Serratia marcescens is a well-established as a nosocomial pathogen, resulting in considerable morbidity and mortality in immunocompromised patients. The aim of this study was to investigate an outbreak of Serratia marcescens at the Orthopaedic Clinic of the Clinical Center University of Sarajevo. Methods. A total of 96 strains from 79 patients were isolated. The isolates were identified by conventional methods. Susceptibility testing was performed by the discdiffusion method following CLSI guidelines. Results were confirmed by VITEC-2 Compact. Results. From January to December 2010, 96 strains from 79 patients were isolated at the Orthopaedic Clinic of the Clinical Center, University of Sarajevo.The strains were isolated from wound swabs, blood cultures and cerebrospinal fluid. The strains were identifed using current phenotypic methods as Serratia marcescens with identical biochemical characteristics and antibiotic susceptibility patterns. All strains were susceptible to imipenem, meropenem, amikacin, ciprofloxacin, levofloxacin and piperacillin/tazobactam. The infection control team was alerted and after investigation they discovered the same phenotype of Serratia marcescens in the anaesthetic vials used in procedures. This outbreak was extremely difficult to terminate, even with cohorting of patients, sterilisation of equipment, reinforcement of handwashing and deep-cleaning of facilities. The implementation of new control measures terminated the outbreak in February 2011. Conclusion. Continuous monitoring of nosocomial infections is indispensable. Phenotypic characterization of the isolates is useful for studying the relationship of microbial pathogens. The relationship of one clinical isolate to another during an outbreak is important in motivating the search for a common source or mode of transmission.

  3. Genome evolution and plasticity of Serratia marcescens, an important multidrug-resistant nosocomial pathogen.

    Science.gov (United States)

    Iguchi, Atsushi; Nagaya, Yutaka; Pradel, Elizabeth; Ooka, Tadasuke; Ogura, Yoshitoshi; Katsura, Keisuke; Kurokawa, Ken; Oshima, Kenshiro; Hattori, Masahira; Parkhill, Julian; Sebaihia, Mohamed; Coulthurst, Sarah J; Gotoh, Naomasa; Thomson, Nicholas R; Ewbank, Jonathan J; Hayashi, Tetsuya

    2014-08-01

    Serratia marcescens is an important nosocomial pathogen that can cause an array of infections, most notably of the urinary tract and bloodstream. Naturally, it is found in many environmental niches, and is capable of infecting plants and animals. The emergence and spread of multidrug-resistant strains producing extended-spectrum or metallo beta-lactamases now pose a threat to public health worldwide. Here we report the complete genome sequences of two carefully selected S. marcescens strains, a multidrug-resistant clinical isolate (strain SM39) and an insect isolate (strain Db11). Our comparative analyses reveal the core genome of S. marcescens and define the potential metabolic capacity, virulence, and multidrug resistance of this species. We show a remarkable intraspecies genetic diversity, both at the sequence level and with regards genome flexibility, which may reflect the diversity of niches inhabited by members of this species. A broader analysis with other Serratia species identifies a set of approximately 3,000 genes that characterize the genus. Within this apparent genetic diversity, we identified many genes implicated in the high virulence potential and antibiotic resistance of SM39, including the metallo beta-lactamase and multiple other drug resistance determinants carried on plasmid pSMC1. We further show that pSMC1 is most closely related to plasmids circulating in Pseudomonas species. Our data will provide a valuable basis for future studies on S. marcescens and new insights into the genetic mechanisms that underlie the emergence of pathogens highly resistant to multiple antimicrobial agents.

  4. Characterization of a new TEM-derived beta-lactamase produced in a Serratia marcescens strain.

    OpenAIRE

    Perilli, M.; Felici, A.; Franceschini, N; De Santis, A; Pagani, L.(Physics Department, Università degli Studi and INFN, 16146 Genova, Italy); Luzzaro, F.; Oratore, A; Rossolini, G. M.; Knox, J R; Amicosante, G

    1997-01-01

    A natural TEM variant beta-lactamase was isolated from an epidemic strain of Serratia marcescens. Nucleotide gene sequencing revealed multiple point mutations located in the 42-to-44 tripeptide and positions 145 to 146, 178, and 238. In addition, a glutamic acid 212 deletion was also found. The purified enzyme was studied from a kinetic point of view, revealing the highest catalytic efficiency (k[cat]/Km) values for ceftazidime and aztreonam compared with the TEM-1 prototype enzyme. The in vi...

  5. Sepsis and Hemocyte Loss in Honey Bees (Apis mellifera) Infected with Serratia marcescens Strain Sicaria.

    Science.gov (United States)

    Burritt, Nancy L; Foss, Nicole J; Neeno-Eckwall, Eric C; Church, James O; Hilger, Anna M; Hildebrand, Jacob A; Warshauer, David M; Perna, Nicole T; Burritt, James B

    2016-01-01

    Global loss of honey bee colonies is threatening the human food supply. Diverse pathogens reduce honey bee hardiness needed to sustain colonies, especially in winter. We isolated a free-living Gram negative bacillus from hemolymph of worker honey bees (Apis mellifera) found separated from winter clusters. In some hives, greater than 90% of the dying bees detached from the winter cluster were found to contain this bacterium in their hemolymph. Throughout the year, the same organism was rarely found in bees engaged in normal hive activities, but was detected in about half of Varroa destructor mites obtained from colonies that housed the septic bees. Flow cytometry of hemolymph from septic bees showed a significant reduction of plasmatocytes and other types of hemocytes. Interpretation of the16S rRNA sequence of the bacterium indicated that it belongs to the Serratia genus of Gram-negative Gammaproteobacteria, which has not previously been implicated as a pathogen of adult honey bees. Complete genome sequence analysis of the bacterium supported its classification as a novel strain of Serratia marcescens, which was designated as S. marcescens strain sicaria (Ss1). When compared with other strains of S. marcescens, Ss1 demonstrated several phenotypic and genetic differences, including 65 genes not previously found in other Serratia genomes. Some of the unique genes we identified in Ss1 were related to those from bacterial insect pathogens and commensals. Recovery of this organism extends a complex pathosphere of agents which may contribute to failure of honey bee colonies.

  6. The role of Serratia marcescens in soft contact lens associated ocular infections. A review.

    Science.gov (United States)

    Parment, P A

    1997-02-01

    Serratia marcescens is a Gram negative rod which for a century and a half was considered a harmless saphrophyte. However, medical technology and the use of antibacterial agents have created ecological niches for this bacterium, which is now a medical problem. The bacterium is encountered in connection with contact lens keratitis, often associated with contaminated contact lens solutions. The concentrations of chlorhexidin and thiomersal required in contact lens solution to suppress the bacterium have been proved toxic to the eye. Modern contact lens solutions with biguanids have rapid killing kinetics, while in solutions with polyquaternium S. marcescens can survive in reduced numbers for up to 72 hours. The adherence of a specific isolate of Serratia to hydrogel lenses increased with decreased water content of the lenses. However, there has been no correlation between hydrophobicity markers or hemagglutinins and adherence to contact lenses or urinary tract epithelium. When handling medical plastic devices, such as contact lenses, strictly enforced hygiene remains the most important method to combat environmental bacteria such as Serratia marcescens.

  7. Failed Reverse Total Shoulder Arthroplasty Caused by Recurrent Candida glabrata Infection with Prior Serratia marcescens Coinfection

    Science.gov (United States)

    Skedros, John G.; Keenan, Kendra E.; Updike, Wanda S.; Oliver, Marquam R.

    2014-01-01

    This report describes a 58-year-old insulin-dependent diabetic male patient who initially sustained a proximal humerus fracture from a fall. The fracture fixation failed and then was converted to a humeral hemiarthroplasty, which became infected with Candida glabrata and Serratia marcescens. After these infections were believed to be cured with antibacterial and antifungal treatments and two-stage irrigation and debridement, he underwent conversion to a reverse total shoulder arthroplasty. Unfortunately, the C. glabrata infection recurred and, nearly 1.5 years after implantation of the reverse total shoulder, he had a resection arthroplasty (removal of all implants and cement). His surgical and pharmacologic treatment concluded with (1) placement of a tobramycin-impregnated cement spacer also loaded with amphotericin B, with no plan for revision arthroplasty (i.e., the spacer was chronically retained), and (2) chronic use of daily oral fluconazole. We located only three reported cases of Candida species causing infection in shoulder arthroplasties (two C. albicans, one C. parapsilosis). To our knowledge, a total shoulder arthroplasty infected with C. glabrata has not been reported, nor has a case of a C. glabrata and S. marcescens periprosthetic coinfection in any joint. In addition, it is well known that S. marcescens infections are uncommon in periprosthetic joint infections. PMID:25431708

  8. Failed Reverse Total Shoulder Arthroplasty Caused by Recurrent Candida glabrata Infection with Prior Serratia marcescens Coinfection

    Directory of Open Access Journals (Sweden)

    John G. Skedros

    2014-01-01

    Full Text Available This report describes a 58-year-old insulin-dependent diabetic male patient who initially sustained a proximal humerus fracture from a fall. The fracture fixation failed and then was converted to a humeral hemiarthroplasty, which became infected with Candida glabrata and Serratia marcescens. After these infections were believed to be cured with antibacterial and antifungal treatments and two-stage irrigation and debridement, he underwent conversion to a reverse total shoulder arthroplasty. Unfortunately, the C. glabrata infection recurred and, nearly 1.5 years after implantation of the reverse total shoulder, he had a resection arthroplasty (removal of all implants and cement. His surgical and pharmacologic treatment concluded with (1 placement of a tobramycin-impregnated cement spacer also loaded with amphotericin B, with no plan for revision arthroplasty (i.e., the spacer was chronically retained, and (2 chronic use of daily oral fluconazole. We located only three reported cases of Candida species causing infection in shoulder arthroplasties (two C. albicans, one C. parapsilosis. To our knowledge, a total shoulder arthroplasty infected with C. glabrata has not been reported, nor has a case of a C. glabrata and S. marcescens periprosthetic coinfection in any joint. In addition, it is well known that S. marcescens infections are uncommon in periprosthetic joint infections.

  9. Optimization of prodigiosin production by Serratia marcescens using crude glycerol and enhancing production using gamma radiation

    Directory of Open Access Journals (Sweden)

    Nora M. Elkenawy

    2017-03-01

    Full Text Available Prodigiosin is a red pigment produced by Serratia marcescens. Prodigiosin is regarded as a promising drug owing to its reported characteristics of possessing anti-microbial, anti-cancer, and immunosuppressive activity. A factorial design was applied to generate a set of 32 experimental combinations to study the optimal conditions for pigment production using crude glycerol obtained from local biodiesel facility as carbon source for the growth of Serratia marcescens. The maximum production (870 unit/cell was achieved at 22 °C, at pH 9 with the addition of 1% (w/v peptone and 109 cell/ml inoculum size after 6 days of incubation. Gamma radiation at dose 200 Gy was capable of doubling the production of the pigment using the optimized conditions and manipulating production temperature. Our results indicate that we have designed an economic medium supporting enhanced Serratia marcescens MN5 prodigiosin production giving an added value for crude glycerol obtained from biodiesel industry.

  10. Intraphagocytic bactericidal activity of ofloxacin compared with that of aztreonam and ceftriaxone against Serratia marcescens.

    Science.gov (United States)

    Traub, W H; Spohr, M; Bauer, D

    1986-02-01

    Addition of phenylbutazone (2 mg/ml) to 55 vol % of fresh defibrinated human blood permitted leukocytic ingestion of serum-resistant Serratia marcescens bacteria, but blocked phagocytic killing activity. The group A (phage tail) bacteriocin bA+ 16 served to kill extraphagocytic test bacteria. At greater than or equal to 2 X MBC, the DNA gyrase inhibitor ofloxacin revealed potent intraphagocytic bactericidal activity against S. marcescens test bacteria (99% kill; 3 h observation period) which corresponded to that of the control drug rifampin (97% kill). The monobactam aztreonam (11% kill) and the third generation cephalosporin ceftriaxone (14% kill) corresponded to cefotaxime (26% kill) in terms of suboptimal intraphagocytic activity. Ofloxacin and aztreonam yielded additive effects following combination of supra-(2 X MIC) and inhibitory (MIC), but not sub-inhibitory (0.5 X MIC) concentrations with 55 vol % of defibrinated human blood against S. marcescens and Escherichia coli control strain ATCC 25922; sub- and inhibitory concentrations of ceftriaxone yielded indifferent effects.

  11. The PhoP/PhoQ system and its role in Serratia marcescens pathogenesis.

    Science.gov (United States)

    Barchiesi, Julieta; Castelli, María Eugenia; Di Venanzio, Gisela; Colombo, María Isabel; García Véscovi, Eleonora

    2012-06-01

    Serratia marcescens is able to invade, persist, and multiply inside nonphagocytic cells, residing in nonacidic, nondegradative, autophagosome-like vacuoles. In this work, we have examined the physiological role of the PhoP/PhoQ system and its function in the control of critical virulence phenotypes in S. marcescens. We have demonstrated the involvement of the PhoP/PhoQ system in the adaptation of this bacterium to growth on scarce environmental Mg(2+), at acidic pH, and in the presence of polymyxin B. We have also shown that these environmental conditions constitute signals that activate the PhoP/PhoQ system. We have found that the two S. marcescens mgtE orthologs present a conserved PhoP-binding motif and demonstrated that mgtE1 expression is PhoP dependent, reinforcing the importance of PhoP control in magnesium homeostasis. Finally, we have demonstrated that phoP expression is activated intracellularly and that a phoP mutant strain is defective in survival inside epithelial cells. We have shown that the Serratia PhoP/PhoQ system is involved in prevention of the delivery to degradative/acidic compartments.

  12. Ethyl methanesulfonate mutagenesis-enhanced mineral phosphate solubilization by groundnut-associated Serratia marcescens GPS-5.

    Science.gov (United States)

    Tripura, Chaturvedula; Sashidhar, Burla; Podile, Appa Rao

    2007-02-01

    Twenty-three bacterial isolates were screened for their mineral phosphate-solubilizing (MPS) ability on Pikovskaya and National Botanical Research Institute's phosphate (NBRIP) agar. The majority of the isolates exhibited a strong ability to solubilize hydroxyapatite in both solid and liquid media. The solubilization in liquid medium corresponded with a decrease in the pH of the medium. Serratia marcescens GPS-5, known for its biocontrol of late leaf spot in groundnut, emerged as the best solubilizer. S. marcescens GPS-5 was subjected to ethyl methanesulfonate (EMS) mutagenesis, and a total of 1700 mutants, resulting after 45 minutes of exposure, were screened on buffered NBRIP medium for alterations in MPS ability compared with that of the wild type. Seven mutants with increased (increased-MPS mutants) and 6 mutants with decreased (decreased-MPS mutants) MPS ability were isolated. All seven increased-MPS mutants were efficient at solubilizing phosphate in both solid and liquid NBRIP medium. Among the increased-MPS mutants, EMS XVIII Sm-35 showed the maximum (40%) increase in the amount of phosphate released in liquid medium compared with wild-type S. marcescens GPS-5, therefore, it would be a useful microbial inoculant in groundnut cultivation. EMS III Sm W, a nonpigmented mutant, showed the lowest solubilization of phosphate among the 6 decreased-MPS mutants.

  13. Outbreak of a cluster with epidemic behavior due to Serratia marcescens after colistin administration in a hospital setting.

    Science.gov (United States)

    Merkier, Andrea Karina; Rodríguez, María Cecilia; Togneri, Ana; Brengi, Silvina; Osuna, Carolina; Pichel, Mariana; Cassini, Marcelo H; Centrón, Daniela

    2013-07-01

    Serratia marcescens causes health care-associated infections with important morbidity and mortality. Particularly, outbreaks produced by multidrug-resistant isolates of this species, which is already naturally resistant to several antibiotics, including colistin, are usually described with high rates of fatal outcomes throughout the world. Thus, it is important to survey factors associated with increasing frequency and/or emergence of multidrug-resistant S. marcescens nosocomial infections. We report the investigation and control of an outbreak with 40% mortality due to multidrug-resistant S. marcescens infections that happened from November 2007 to April 2008 after treatment with colistin for Acinetobacter baumannii meningitis was started at hospital H1 in 2005. Since that year, the epidemiological pattern of frequently recovered species has changed, with an increase of S. marcescens and Proteus mirabilis infections in 2006 in concordance with a significant decrease of the numbers of P. aeruginosa and A. baumannii isolates. A single pulsed-field gel electrophoresis (PFGE) cluster of S. marcescens isolates was identified during the outbreak. When this cluster was compared with S. marcescens strains (n = 21) from 10 other hospitals (1997 to 2010), it was also identified in both sporadic and outbreak isolates circulating in 4 hospitals in Argentina. In132::ISCR1::blaCTX-M-2 was associated with the multidrug-resistant cluster with epidemic behavior when isolated from outbreaks. Standard infection control interventions interrupted transmission of this cluster even when treatment with colistin continued in several wards of hospital H1 until now. Optimizing use of colistin should be achieved simultaneously with improved infection control to prevent the emergence of species naturally resistant to colistin, such as S. marcescens and P. mirabilis.

  14. Serratia marcescens arn, a PhoP-regulated locus necessary for polymyxin B resistance.

    Science.gov (United States)

    Lin, Quei Yen; Tsai, Yi-Lin; Liu, Ming-Che; Lin, Wei-Cheng; Hsueh, Po-Ren; Liaw, Shwu-Jen

    2014-09-01

    Polymyxins, which are increasingly being used to treat infections caused by multidrug-resistant bacteria, perform poorly against Serratia marcescens. To investigate the underlying mechanisms, Tn5 mutagenesis was performed and two mutants exhibiting increased polymyxin B (PB) susceptibility were isolated. The mutants were found to have Tn5 inserted into the arnB and arnC genes. In other bacteria, arnB and arnC belong to the seven-gene arn operon, which is involved in lipopolysaccharide (LPS) modification. LPSs of arn mutants had greater PB-binding abilities than that of wild-type LPS. Further, we identified PhoP, a bacterial two-component response regulator, as a regulator of PB susceptibility in S. marcescens. By the reporter assay, we found PB- and low-Mg2+-induced expression of phoP and arn in the wild-type strain but not in the phoP mutant. Complementation of the phoP mutant with the full-length phoP gene restored the PB MIC and induction by PB and low Mg2+ levels, as in the wild type. An electrophoretic mobility shift assay (EMSA) further demonstrated that PhoP bound directly to the arn promoter. The PB challenge test confirmed that pretreatment with PB and low Mg2+ levels protected S. marcescens from a PB challenge in the wild-type strain but not in the phoP mutant. Real-time reverse transcriptase-PCR also indicated that PB serves as a signal to regulate expression of ugd, a gene required for LPS modification, in S. marcescens through a PhoP-dependent pathway. Finally, we found that PB-resistant clinical isolates displayed greater expression of arnA upon exposure to PB than did susceptible isolates. This is the first report to describe the role of S. marcescens arn in PB resistance and its modulation by PB and Mg2+ through the PhoP protein.

  15. Use of quantitative real-time PCR for direct detection of serratia marcescens in marine and other aquatic environments.

    Science.gov (United States)

    Joyner, Jessica; Wanless, David; Sinigalliano, Christopher D; Lipp, Erin K

    2014-03-01

    Serratia marcescens is the etiological agent of acroporid serratiosis, a distinct form of white pox disease in the threatened coral Acropora palmata. The pathogen is commonly found in untreated human waste in the Florida Keys, which may contaminate both nearshore and offshore waters. Currently there is no direct method for detection of this bacterium in the aquatic or reef environment, and culture-based techniques may underestimate its abundance in marine waters. A quantitative real-time PCR assay was developed to detect S. marcescens directly from environmental samples, including marine water, coral mucus, sponge tissue, and wastewater. The assay targeted the luxS gene and was able to distinguish S. marcescens from other Serratia species with a reliable quantitative limit of detection of 10 cell equivalents (CE) per reaction. The method could routinely discern the presence of S. marcescens for as few as 3 CE per reaction, but it could not be reliably quantified at this level. The assay detected environmental S. marcescens in complex sewage influent samples at up to 761 CE ml(-1) and in septic system-impacted residential canals in the Florida Keys at up to 4.1 CE ml(-1). This detection assay provided rapid quantitative abilities and good sensitivity and specificity, which should offer an important tool for monitoring this ubiquitous pathogen that can potentially impact both human health and coral health.

  16. Serratia marcescens in a neonatal intensive care unit: two long-term multiclone outbreaks in a 10-year observational study.

    Science.gov (United States)

    Casolari, Chiara; Pecorari, Monica; Della Casa, Elisa; Cattani, Silvia; Venturelli, Claudia; Fabio, Giuliana; Tagliazucchi, Sara; Serpini, Giulia Fregni; Migaldi, Mario; Marchegiano, Patrizia; Rumpianesi, Fabio; Ferrari, Fabrizio

    2013-10-01

    We investigated two consecutive Serratia marcescens (S. marcescens) outbreaks which occurred in a neonatal intensive care unit (NICU) of a tertiary level hospital in North Italy in a period of 10 years (January 2003-December 2012). Risk factors associated with S. marcescens acquisition were evaluated by a retrospective case-control study. A total of 21,011 clinical samples was examined: S. marcescens occurred in 127 neonates: 43 developed infection and 3 died. Seven clusters were recorded due to 12 unrelated clones which persisted for years in the ward, although no environmental source was found. The main epidemic clone A sustaining the first cluster in 2003 reappeared in 2010 as an extended spectrum ?-lactamase (ESBL)-producing strain and supporting the second epidemic. Birth weight, gestational age, use of invasive devices and length of stay in the ward were significantly related to S. marcescens acquisition. The opening of a new ward for non-intensive care-requiring neonates, strict adherence to alcoholic hand disinfection, the timely identification and isolation of infected and colonized neonates assisted in containing the epidemics. Genotyping was effective in tracing the evolution and dynamics of the clones demonstrating their long-term persistence in the ward.

  17. Potential transmission of Pantoea spp. and Serratia marcescens (Enterobacteriales: Enterobacteriaceae) to plants by Lygus hesperus (Hemiptera: Miridae).

    Science.gov (United States)

    Cooper, W Rodney; Nicholson, Scott J; Puterka, Gary J

    2014-02-01

    Lygus hesperus Knight (Hemiptera: Miridae) is a key agricultural pest in the western United States. In a recent study, proteins from Pantoea ananatis and Serratia marcescens (Enterobacteriales: Enterobacteriaceae) were identified in diet that was stylet probed and fed on by L. hesperus adults. P. ananatis and S. marcescens are ubiquitous bacteria that infect a wide range of crops. The objective of our study was to determine whether L. hesperus transfer P. ananatis and S. marcescens to food substrates during stylet-probing activities. Sucrose (5%) was spread under parafilm and exposed to adult L. hesperus for 24 h. Diet similarly prepared but not exposed to insects was used for controls. MacConkey agar was inoculated with stylet-probed or control diets and incubated at 25 degrees C. After 24 h, bacterial colonies were observed on agar that was inoculated with stylet-probed diet, but were not observed on agar inoculated with control diet. Isolated bacterial colonies were putatively identified as either Pantoea spp. or S. marcescens using the API 20e identification kit. These results indicate that L. hesperus is capable of vectoring P. ananatis and S. marcescens.

  18. Serratia marcescens suppresses host cellular immunity via the production of an adhesion-inhibitory factor against immunosurveillance cells.

    Science.gov (United States)

    Ishii, Kenichi; Adachi, Tatsuo; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

    2014-02-28

    Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachment of both silkworm hemocytes and murine peritoneal macrophages. Incubation of silkworm hemocytes or murine macrophages with serralysin resulted in degradation of the cellular immune factor BmSPH-1 or calreticulin, respectively. Furthermore, serralysin suppressed in vitro phagocytosis of bacteria by hemocytes and in vivo bacterial clearance in silkworms. Disruption of the ser gene in S. marcescens attenuated its host killing ability in silkworms and mice. These findings suggest that serralysin metalloprotease secreted by S. marcescens suppresses cellular immunity by decreasing the adhesive properties of immunosurveillance cells, thereby contributing to bacterial pathogenesis.

  19. Systematic Analysis of White Pox Disease in Acropora palmata of the Florida Keys and Role of Serratia marcescens.

    Science.gov (United States)

    Joyner, Jessica L; Sutherland, Kathryn P; Kemp, Dustin W; Berry, Brett; Griffin, Ashton; Porter, James W; Amador, Molly H B; Noren, Hunter K G; Lipp, Erin K

    2015-07-01

    White pox disease (WPD) affects the threatened elkhorn coral, Acropora palmata. Owing in part to the lack of a rapid and simple diagnostic test, there have been few systematic assessments of the prevalence of acroporid serratiosis (caused specifically by Serratia marcescens) versus general WPD signs. Six reefs in the Florida Keys were surveyed between 2011 and 2013 to determine the disease status of A. palmata and the prevalence of S. marcescens. WPD was noted at four of the six reefs, with WPD lesions found on 8 to 40% of the colonies surveyed. S. marcescens was detected in 26.9% (7/26) of the WPD lesions and in mucus from apparently healthy colonies both during and outside of disease events (9%; 18/201). S. marcescens was detected with greater frequency in A. palmata than in the overlying water column, regardless of disease status (P = 0.0177). S. marcescens could not be cultured from A. palmata but was isolated from healthy colonies of other coral species and was identified as pathogenic pulsed-field gel electrophoresis type PDR60. WPD lesions were frequently observed on the reef, but unlike in prior outbreaks, no whole-colony death was observed. Pathogenic S. marcescens was circulating on the reef but did not appear to be the primary pathogen in these recent WPD episodes, suggesting that other pathogens or stressors may contribute to signs of WPD. Results highlight the critical importance of diagnostics in coral disease investigations, especially given that field manifestation of disease may be similar, regardless of the etiological agent.

  20. Spaceflight Causes Increased Virulence of Serratia Marcescens on a Drosophila Melanogaster Host

    Science.gov (United States)

    Bhattacharya, Sharmila; Wade, William; Clemens-Grisham, Rachel; Hosamani, Ravikumar; Bhardwaj, Shilpa R.; Lera, Matthew P.; Gresser, Amy L.

    2015-01-01

    Drosophila melanogaster, or the fruit fly, has long been an important organism for Earth-based research, and is now increasingly utilized as a model system to understand the biological effects of spaceflight. Studies in Drosophila melanogaster have shown altered immune responses in 3rd instar larvae and adult males following spaceflight, changes similar to those observed in astronauts. In addition, spaceflight has also been shown to affect bacterial physiology, as evidenced by studies describing altered virulence of Salmonella typhimurium following spaceflight and variation in biofilm growth patterns for the opportunistic pathogen Pseudomonas aeruginosa during flight. We recently sent Serratia marcescens Db11, a Drosophila pathogen and an opportunistic human pathogen, to the ISS on SpaceX-5 (Fruit Fly Lab-01). S. marcescens samples were stored at 4degC for 24 days on-orbit and then allowed to grow for 120 hours at ambient station temperature before being returned to Earth. Upon return, bacteria were isolated and preserved in 50% glycerol or RNAlater. Storage, growth, and isolation for ground control samples were performed using the same procedures. Spaceflight and ground samples stored in 50% glycerol were diluted and injected into 5-7-day-old ground-born adult D. melanogaster. Lethality was significantly greater in flies injected with the spaceflight samples compared to those injected with ground bacterial samples. These results indicate a shift in the virulence profile of the spaceflight S. marcescens Db11 and will be further assessed with molecular biological analyses. Our findings strengthen the conclusion that spaceflight impacts the virulence of bacterial pathogens on model host organisms such as the fruit fly. This research was supported by NASA's ISS Program Office (ISSPO) and Space Life and Physical Sciences Research and Applications (SLPSRA).

  1. Identification of SlpB, a Cytotoxic Protease from Serratia marcescens.

    Science.gov (United States)

    Shanks, Robert M Q; Stella, Nicholas A; Hunt, Kristin M; Brothers, Kimberly M; Zhang, Liang; Thibodeau, Patrick H

    2015-07-01

    The Gram-negative bacterium and opportunistic pathogen Serratia marcescens causes ocular infections in healthy individuals. Secreted protease activity was characterized from 44 ocular clinical isolates, and a higher frequency of protease-positive strains was observed among keratitis isolates than among conjunctivitis isolates. A positive correlation between protease activity and cytotoxicity to human corneal epithelial cells in vitro was determined. Deletion of prtS in clinical keratitis isolate K904 reduced, but did not eliminate, cytotoxicity and secreted protease production. This indicated that PrtS is necessary for full cytotoxicity to ocular cells and implied the existence of another secreted protease(s) and cytotoxic factors. Bioinformatic analysis of the S. marcescens Db11 genome revealed three additional open reading frames predicted to code for serralysin-like proteases noted here as slpB, slpC, and slpD. Induced expression of prtS and slpB, but not slpC and slpD, in strain PIC3611 rendered the strain cytotoxic to a lung carcinoma cell line; however, only prtS induction was sufficient for cytotoxicity to a corneal cell line. Strain K904 with deletion of both prtS and slpB genes was defective in secreted protease activity and cytotoxicity to human cell lines. PAGE analysis suggests that SlpB is produced at lower levels than PrtS. Purified SlpB demonstrated calcium-dependent and AprI-inhibited protease activity and cytotoxicity to airway and ocular cell lines in vitro. Lastly, genetic analysis indicated that the type I secretion system gene, lipD, is required for SlpB secretion. These genetic data introduce SlpB as a new cytotoxic protease from S. marcescens.

  2. The efficacy of soft contact lens disinfection solutions against Serratia marcescens and Pseudomonas aeruginosa.

    Science.gov (United States)

    Parment, P A; Colucci, B; Nyström, B

    1996-06-01

    Samples of five different solutions for disinfection of soft contact lenses were experimentally inoculated with a strain of Pseudomonas aeruginosa or Serratia marcescens. No bacteria could be detected after one hour in solutions with biguanids, while they survived in reduced number up to 72 h in solutions with polyquaternium as active substance. However, prolonged survival after one week could not be detected. Lenses treated with polyquaternium based contact lens disinfectant solutions overnight may still harbour bacteria, which might increase the risk for bacterial complications, such as keratitis.

  3. Use of colistin and sorbitol for better isolation of Serratia marcescens in clinical samples.

    OpenAIRE

    Grasso, G. M.; D'Errico, M. M.; Schioppa, F.; Romano, F.; Montanaro, D

    1988-01-01

    A comparison was made of different culture media and procedures for detection of Serratia marcescens from faecal, pharyngeal and ocular swabs collected from 213 neonates. MacConkey agar and MacConkey agar with sorbitol (1%) and/or colistin (200 i.u./ml) were used both for primary isolation and after enrichment using Mossel Enterobacteriaceae broth with colistin (200 i.u./ml). The use of MacConkey agar supplemented with colistin for primary isolation improved considerably the isolation rate of...

  4. Remoção de Serratia marcescens (Enterobacteriaceae das mãos pelo uso de diferentes agentes degermantes Removal of Serratia marcescens (Enterobacteriaceae from hands contaminated with different degermants

    Directory of Open Access Journals (Sweden)

    Heloisa Nakai Kwabara

    2002-04-01

    Full Text Available Foi investigado o efeito imediato do sabão, álcool etílico 70%, polivinilpirrolidona-iodo 10% (PVP-I e clorhexidina 4% na remoção de uma amostra de Serratia marcescens aplicada nas mãos de cinco voluntários. Utilizou-se como modelo experimental um quadrado latino contendo dois blocos aleatorizados 5 x 4. No primeiro bloco (baixa contaminação, a taxa de remoção de Serratia marcescens (Enterobacteriaceae das mãos, expressa pelo fator de redução logarítmica (FRL, foi de 2,77 para o PVP-I e o álcool, 2,38 para a clorhexidina e de 1,88 para o sabão. Não houve diferença entre os tratamentos (P > 0,05. No segundo bloco (alta contaminação, o PVP-I (FRL = 5,71 e o álcool (FRL = 5,08 foram mais eficientes do que a clorhexidina (FRL = 2,80 e o sabão (FRL = 2,48 (P > 0,05. Os resultados sugerem que o PVP-I e o álcool podem ser mais eficazes na remoção de Serratia marcescens das mãos altamente contaminadasThe effectiveness of soap, 70% ethyl alcohol, 10% povidone-iodine (PVP-I, 4% chlorhexidine gluconate in removing a strain of Serratia marcescens (Enterobacteriaceae from contaminated hands of five volunteers was studied. The experiments were performed using a Latin square statistical design with two 5 x 4 randomized blocks. The removal rates of Serratia marcescens were estimated by analysis of variance. In the first block (lightly-contamination hand, the use of hand-cleansing agents resulted in 2.77 (PVP-I and alcohol, 2.38 (chlorhexidine, and 1.88 (soap log10 reduction factors (RF in counts of Serratia marcescens applied to the fingertips. There were no significant differences between treatments (P > .05. In the second block (heavily-contamination hand, PVP-I (RF, 5.71 and alcohol (RF, 5.08 were significantly more effective than chlorhexidine (RF, 2.80 and soap (RF, 2.48 (P > .05. The results suggest that PVP-I and 70% ethyl alcohol may be the most effective for removing this Serratia marcescens strain from heavily contaminated

  5. [Control measures against Serratia marcescens colonization at the neonatal intensive care unit of UOEH hospital].

    Science.gov (United States)

    Ikeno, Takako; Tanabe, Tadao; Muratani, Tetsuro; Nakano, Noriko; Kotake, Tomoko; Shirakawa, Yoshitsugu; Taniguchi, Hatsumi; Matsumoto, Tetsuro

    2003-03-01

    In September 2001, twelve neonatal intensive care unit (NICU) patients were found to be colonized with pigment-producing strains of Serratia marcescens. The UOEH Infection Control Group (ICG) committee investigated the source of this epidemic and carried out several remedial measures. Immediate investigation of both the environment and the hands of health care workers were enforced. The most likely means of transmission was thought to be from the hands contaminated with S. marcescens that was found on antiseptic cotton, kept in shared stainless steel canisters, used for wiping the patients' buttocks. Therefore, we suggested the following interventions: 1) abolish the stainless steel canisters, and prepare antiseptic cottons for each patient, 2) monitor cultures with some specimens for all patients in the NICU, 3) periodically investigate the environment, 4) enforce workers to wash and disinfect their hands before and after patient care, 5) use new gloves for each treatment, 6) re-examine and modify the caring procedures for inpatients by the nursing staff. In January 2002, this nosocomial colonization came to an end without any serious infection. One of the key points of this success was the quick response by the clinical staff and ICG committee members to the laboratory results of bacteriological examinations. Furthermore, the early investigation of reservoir and good communication between the clinical staff and ICG committee members mostly prevented this nosocomial colonization from becoming worse.

  6. Biodegradation of Malathion using mixed culture of Serratia marcescens BNA1and Pseudomonas aeruginosa BNA2

    Directory of Open Access Journals (Sweden)

    B Nadalian

    2016-03-01

    Full Text Available Background and Objectives: Organophosphate pesticides are used most commonly for domestic, commercial, and agricultural purposes and have been found to be highly toxic. In essence, bioremediation has become one of the most important tools for removing these compounds in the environment, considering its higher efficiency when compared with the physicochemical methods. Materials and Methods: The biodegradation efficiency of two bacterial strains (i.e. Serratia marcescens BNA1 and Pseudomonas aeruginosa BNA2 were assessed. In order to evaluate Malathion biodegradation, each sample was cultured on mineral salts medium containing Malathion as a sole carbon source. Malathion biodegradation efficiency of the strains was monitored in different culture media. The ability of bacterial isolates to degrade Malathion was studied using gas chromatography. Results: Serratia marcescens BNA1 and Pseudomonas aeruginosa BNA2 were able to degrade Malathion. Biodegradation percentage in different treatments recorded were: BNA1+Ma (33.88%, BNA2+MA (26.45%, BNA1+BNA2+Ma (46/96%, BNA1+Ma+Tween (61.05%, BNA2+Ma+Tween (40.17%, and BNA1+BNA2+Ma+ Tween (67.79%. Conclusion: It could be speculated that the best degradation efficiency can be yielded using mixture of strains plus a surfactant. The results of this study can be used in the bioremediation of Malathion contaminate soil after doing the pilot experiments.

  7. Comparative genome analyses of Serratia marcescens FS14 reveals its high antagonistic potential.

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    Pengpeng Li

    Full Text Available S. marcescens FS14 was isolated from an Atractylodes macrocephala Koidz plant that was infected by Fusarium oxysporum and showed symptoms of root rot. With the completion of the genome sequence of FS14, the first comprehensive comparative-genomic analysis of the Serratia genus was performed. Pan-genome and COG analyses showed that the majority of the conserved core genes are involved in basic cellular functions, while genomic factors such as prophages contribute considerably to genome diversity. Additionally, a Type I restriction-modification system, a Type III secretion system and tellurium resistance genes are found in only some Serratia species. Comparative analysis further identified that S. marcescens FS14 possesses multiple mechanisms for antagonism against other microorganisms, including the production of prodigiosin, bacteriocins, and multi-antibiotic resistant determinants as well as chitinases. The presence of two evolutionarily distinct Type VI secretion systems (T6SSs in FS14 may provide further competitive advantages for FS14 against other microbes. To our knowledge, this is the first report of comparative analysis on T6SSs in the genus, which identifies four types of T6SSs in Serratia spp.. Competition bioassays of FS14 against the vital plant pathogenic bacterium Ralstonia solanacearum and fungi Fusarium oxysporum and Sclerotinia sclerotiorum were performed to support our genomic analyses, in which FS14 demonstrated high antagonistic activities against both bacterial and fungal phytopathogens.

  8. Potential of Chitinolytic Serratia marcescens Strain JPP1 for Biological Control of Aspergillus parasiticus and Aflatoxin

    Directory of Open Access Journals (Sweden)

    Kai Wang

    2013-01-01

    Full Text Available Serratia marcescens strain JPP1 was isolated from peanut hulls in Huai'an city, Jiangsu Province, China. Its potential to inhibit the mycelial growth of Aspergillus parasiticus and the subsequent aflatoxin production was evaluated. The strain JPP1 could produce chitinase to degrade fungal cell walls, which was the main mechanism of strain JPP1 for biocontrol. Scanning electron microscopy of fungi treated with the crude chitinase revealed abnormal morphological changes. While the strain was grown in the peanut hulls-based medium, the chitinase activity reached 7.39 units. RT-PCR analysis showed that the crude chitinase repressed the transcription of genes involved in the aflatoxin gene cluster, such as aflR, aflC (pksL1, and aflO (dmtA genes. By visual agar plate assay and tip culture method, the strain JPP1 exhibited remarkable inhibitory effect on mycelia growth (antifungal ratio >95% and subsequent aflatoxin production (antiaflatoxigenic ratio >98%. An in vitro assay with seed coating agent of bacterial suspension showed that strain JPP1 effectively reduced fungal growth and subsequent aflatoxin production on peanut seeds, and its antagonistic effect was superior to the common agricultural fungicide of carbendazim. These characteristics suggest that S. marcescens JPP1 strain could potentially be utilized for the biological control of phytopathogenic fungi and aflatoxin in Chinese peanut main producing areas.

  9. Potential of chitinolytic Serratia marcescens strain JPP1 for biological control of Aspergillus parasiticus and aflatoxin.

    Science.gov (United States)

    Wang, Kai; Yan, Pei-Sheng; Cao, Li-Xin; Ding, Qing-Long; Shao, Chi; Zhao, Teng-Fei

    2013-01-01

    Serratia marcescens strain JPP1 was isolated from peanut hulls in Huai'an city, Jiangsu Province, China. Its potential to inhibit the mycelial growth of Aspergillus parasiticus and the subsequent aflatoxin production was evaluated. The strain JPP1 could produce chitinase to degrade fungal cell walls, which was the main mechanism of strain JPP1 for biocontrol. Scanning electron microscopy of fungi treated with the crude chitinase revealed abnormal morphological changes. While the strain was grown in the peanut hulls-based medium, the chitinase activity reached 7.39 units. RT-PCR analysis showed that the crude chitinase repressed the transcription of genes involved in the aflatoxin gene cluster, such as aflR, aflC (pksL1), and aflO (dmtA) genes. By visual agar plate assay and tip culture method, the strain JPP1 exhibited remarkable inhibitory effect on mycelia growth (antifungal ratio >95%) and subsequent aflatoxin production (antiaflatoxigenic ratio >98%). An in vitro assay with seed coating agent of bacterial suspension showed that strain JPP1 effectively reduced fungal growth and subsequent aflatoxin production on peanut seeds, and its antagonistic effect was superior to the common agricultural fungicide of carbendazim. These characteristics suggest that S. marcescens JPP1 strain could potentially be utilized for the biological control of phytopathogenic fungi and aflatoxin in Chinese peanut main producing areas.

  10. High-level soluble expression of Serratia marcescens H30 lipase in Escherichia coli.

    Science.gov (United States)

    Su, Erzheng; Xu, Jingjing; Wu, Xiangping

    2015-01-01

    Serratia marcescens lipase (SmL) is an important biocatalyst used to enantioselectively hydrolyze (±)-trans-3-(4-methoxyphynyl) glycidic acid methyl ester. However, the economically justified level recombinant soluble expression of SmL in Escherichia coli has not been established. Thus, fusion genes of lipase from S. marcescens H30 with different fusion tags were constructed and expressed in E. coli. The effects of fusion tags were revealed. A significant increase in recombinant lipase solubility showed that E. coli BL21 (DE3)/pET32a-SmL was a suitable choice for SmL production. To optimize the performance of recombinant SmL production, changes in culture medium compositions and induction conditions were systematically tested. Finally, the recombinant SmL activity and productivity reached approximately 23,000 U/L and 1,278 U/L/H in shake flasks, respectively. This value is the highest SmL activity attained by heterogeneous recombinant expression in E. coli. Lipase activity and productivity reached 19,650 U/L and 1,228 U/L/H, respectively, by scaling up SmL production in a 7.0 L fermenter. The existence of the Trx tag did not influence the chiral selectivity of recombinant SmL. These findings indicate a possibility for soluble and economical SmL expression in E. coli to meet industrial needs.

  11. Interactions between the tropical sea anemone Aiptasia pallida and Serratia marcescens, an opportunistic pathogen of corals.

    Science.gov (United States)

    Krediet, Cory J; Meyer, Julie L; Gimbrone, Nicholas; Yanong, Roy; Berzins, Ilze; Alagely, Ali; Castro, Herman; Ritchie, Kim B; Paul, Valerie J; Teplitski, Max

    2014-06-01

    Coral reefs are under increasing stress caused by global and local environmental changes, which are thought to increase the susceptibility of corals to opportunistic pathogens. In the absence of an easily culturable model animal, the understanding of the mechanisms of disease progression in corals remains fairly limited. In the present study, we tested the susceptibility of the tropical sea anemone Aiptasia pallida to an opportunistic coral pathogen (Serratia marcescens). A. pallida was susceptible to S. marcescens PDL100 and responded to this opportunistic coral pathogen with darkening of the tissues and retraction of tentacles, followed by complete disintegration of polyp tissues. Histological observations revealed loss of zooxanthellae and structural changes in eosinophilic granular cells in response to pathogen infection. A screen of S. marcescens mutants identified a motility and tetrathionate reductase mutants as defective in virulence in the A. pallida infection model. In co-infections with the wild-type strain, the tetrathionate reductase mutant was less fit within the surface mucopolysaccharide layer of the host coral Acropora palmata.

  12. Genome Sequence of Rhizobacterium Serratia marcescens Strain 90-166, Which Triggers Induced Systemic Resistance and Plant Growth Promotion.

    Science.gov (United States)

    Jeong, Haeyoung; Kloepper, Joseph W; Ryu, Choong-Min

    2015-06-18

    The rhizobacterium Serratia marcescens strain 90-166 elicits induced systemic resistance against plant pathogens and herbivores and promotes plant growth under greenhouse and field conditions. Strain 90-166 secretes volatile compounds, siderophores, salicylic acid, and quorum-sensing autoinducers as bacterial determinants toward plant health. Herein, we present its draft genome sequence.

  13. Survival of Serratia marcescens in benzalkonium chloride and in multiple-dose medication vials: relationship to epidemic septic arthritis.

    Science.gov (United States)

    Nakashima, A K; Highsmith, A K; Martone, W J

    1987-01-01

    In an epidemic of septic arthritis due to Serratia marcescens, the intra-articular injection of contaminated methylprednisolone may have played a key role. The epidemic strain was found in used multiple-dose vials of methylprednisolone and in a canister of cotton balls soaked in benzalkonium chloride. The cotton balls had been used for antisepsis and disinfection. Growth characteristics of the epidemic strain of S. marcescens were compared with those of control strains of S. marcescens which had been obtained from unrelated nosocomial outbreaks. The epidemic strain was able to survive in 1:100 dilutions of benzalkonium chloride and was able to grow to greater than 10(5) CFU/ml in multiple-dose vials of methylprednisoline; control strains could not be recovered after 24 h in the same solutions. The preservative in methylprednisolone is gamma-myristyl picolinium chloride, a compound chemically related to benzalkonium chloride. We speculate that the epidemic strain of S. marcescens, which was resistant to benzalkonium chloride, had cross-resistance to gamma-myristyl picolinium chloride. If the cotton balls were used to disinfect the tops of the multiple-dose vials of methylprednisolone, small numbers of organisms subsequently introduced into the solution could have grown to high concentrations. PMID:3298309

  14. EXPRESSION OF A CHITINASE GENE FROM SERRATIA-MARCESCENS IN LACTOCOCCUS-LACTIS AND LACTOBACILLUS-PLANTARUM

    NARCIS (Netherlands)

    BRURBERG, MB; HAANDRIKMAN, AJ; LEENHOUTS, KJ; VENEMA, G; NES, IF

    1994-01-01

    A chitinase gene from the Gram-negative bacterium Serratia marcescens BJL200 was cloned in Lactococcus lactis subsp. lactis MG1363 and in the silage inoculum strain Lactobacillus plantarum E19b. The chitinase gene was expressed as an active enzyme at a low level in Lactococcus lactis, when cloned in

  15. The dependence of quorum sensing in Serratia marcescens JG on the transcription of luxS gene.

    Science.gov (United States)

    Sun, Shu-Jing; Liu, Yu-Chen; Sun, Jiao; Zhu, Hu

    2015-06-01

    Bacteria communicate with one another using chemical signal molecules. This phenomenon termed quorum sensing enables the bacteria to monitor the environment for other bacteria and to alter behavior on a population-wide scale in response to cell density. Serratia marcescens JG, a quorum sensing bacterium, can secrete a furanosyl borate diester autoinducer (AI-2) in the exponential phase of growth. In this study, to further investigate the regulation of AI-2 production in S. marcescens JG, the pfs and luxS promoter fusions to an operon luxCDABE reporter were constructed in a low-copy-number vector pBR322K, which allows an examination of transcription of the genes in the pathway for signal synthesis. The results show that the luxS expression is constitutive, and the transcription of luxS is tightly correlated with AI-2 production in S. marcescens JG because the peaks of AI-2 production and transcriptional level of luxS appear at the same time point. The close relation of the profiles of luxS transcription and AI-2 production was also confirmed with real-time PCR technology. These results support the hypothesis that the quorum sensing in S. marcescens JG is luxS dependent.

  16. Outbreak of Serratia marcescens colonization and infection traced to a Healthcare worker with long-term carriage on the hands

    NARCIS (Netherlands)

    de Vries, Jutte J. C.; Baas, Willy H.; van der Ploeg, Kees; Heesink, Albert; Degener, John E.; Arends, Jan P.

    2006-01-01

    objective. To reveal the source of a nosocomial outbreak of colonization and infection with a strain of Serratia marcescens positive for Guiana extended-spectrum beta-lactamase 1 (GES-1) that occurred among patients in a neurosurgical intensive care unit (ICU) in a Dutch university medical center fr

  17. Serratia marcescens bacteraemia outbreak in haemodialysis patients with tunnelled catheters due to colonisation of antiseptic solution. Experience at 4 hospitals

    Directory of Open Access Journals (Sweden)

    José L. Merino

    2016-11-01

    Conclusions: The presence of bacteraemia due to unconventional germs should alert us to a potential outbreak. The application of a solution contaminated by S. marcescens in haemodialysis catheters was the source of bacteraemia. The intravenous antibiotic treatment and the catheter lock solution allowed an excellent survival of patients and catheters.

  18. Potential transmission of Pantoea spp. and Serratia marcescens (Enterobacteriales: Enterobacteriaceae) to plants by Lygus hesperus (Hemiptera: Miridae)

    Science.gov (United States)

    Lygus hesperus Knight (Hemiptera: Miridae) is a key agricultural pest in the western United States. In a recent study, proteins from Pantoea ananatis and Serratia marcescens (Enterobacteriales: Enterobacteriaceae) were identified in diet that was stylet-probed and fed upon by L. hesperus adults. P...

  19. Molecular detection and analysis of a novel metalloprotease gene of entomopathogenic Serratia marcescens strains in infected Galleria mellonella.

    Science.gov (United States)

    Tambong, J T; Xu, R; Sadiku, A; Chen, Q; Badiss, A; Yu, Q

    2014-04-01

    Serratia marcescens strains isolated from entomopathogenic nematodes (Rhabditis sp.) were examined for their pathogenicity and establishment in wax moth (Galleria mellonella) larvae. All the Serratia strains were potently pathogenic to G. mellonella larvae, leading to death within 48 h. The strains were shown to possess a metalloprotease gene encoding for a novel serralysin-like protein. Rapid establishment of the bacteria in infected larvae was confirmed by specific polymerase chain reaction (PCR) detection of a DNA fragment encoding for this protein. Detection of the viable Serratia strains in infected larvae was validated using the SYBR Green reverse transcriptase real-time PCR assay targeting the metalloprotease gene. Nucleotide sequences of the metalloprotease gene obtained in our study showed 72 single nucleotide polymorphisms (SNP) and 3 insertions compared with the metalloprotease gene of S. marcescens E-15. The metalloprotease gene had 60 synonymous and 8 nonsynonymous substitutions relative to the closest GenBank entry, S. marcescens E-15. A comparison of the amino acid composition of the new serralysin-like protein with that of the serralysin protein of S. marcescens E-15 revealed differences at 11 positions and a new aspartic acid residue. Analysis of the effect of protein variation suggests that a new aspartic acid residue resulting from nonsynonymous nucleotide mutations in the protein structure could have the most significant effect on its biological function. The new metalloprotease gene and (or) its product could have applications in plant agricultural biotechnology.

  20. Synthesis of hydroxytyrosol, 2-hydroxyphenylacetic acid, and 3-hydroxyphenylacetic acid by differential conversion of tyrosol isomers using Serratia marcescens strain.

    Science.gov (United States)

    Allouche, Noureddine; Sayadi, Sami

    2005-08-10

    We investigated to develop an effective procedure to produce the potentially high-added-value phenolic compounds through bioconversion of tyrosol isomers. A soil bacterium, designated Serratia marcescens strain, was isolated on the basis of its ability to grow on p-tyrosol (4-hydroxyphenylethanol) as a sole source of carbon and energy. During growth on p-tyrosol, Ser. marcescens strain was capable of promoting the formation of hydroxytyrosol. To achieve maximal hydroxytyrosol yield, the growth state of the culture utilized for p-tyrosol conversion as well as the amount of p-tyrosol that was treated were optimized. The optimal yield of hydroxytyrosol (80%) was obtained by Ser. marcescens growing cells after a 7-h incubation using 2 g/L of p-tyrosol added at the end of the exponential phase to a culture pregrown on 1 g/L of p-tyrosol. Furthermore, the substrate specificity of the developed biosynthesis was investigated using m-tyrosol (3-hydroxyphenylethanol) and o-tyrosol (2-hydroxyphenylethanol) as substrates. Ser. marcescens strain transformed completely m-tyrosol and o-tyrosol into 3-hydroxyphenylacetic acid and 2-hydroxyphenylacetic acid, respectively, via the oxidation of the side chain carbon of the treated substrates. This proposed procedure is an alternative approach to obtain hydroxytyrosol, 2-hydroxyphenylacetic acid, and 3-hydroxyphenylacetic acid in an environmentally friendly way which could encourage their use as alternatives in the search for replacement of synthetic food additives.

  1. Effect of the bacterium Serratia marcescens SCBI on the longevity and reproduction of the nematode Caenorhabditis briggsae KT0001

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    Lancaster Jeremiah D

    2012-12-01

    Full Text Available Abstract Background Extensive research effort has advanced our understanding of Caenorhabditis as a model system, but its natural association with bacteria remains to be explored in an ecological context. Explored associations vary vastly from mutualistic to parasitic. Serratia marcescens has been shown to be pathogenic to Caenorhabditis with a fitness cost. The recent isolation of an entomopathogenic Caenorhabditis briggsae KT0001/S. marcescens SCBI association from the wild has allowed us to examine under laboratory conditions whether such an association poses a serious cost to Caenorhabditis as previously surmised for other Serratia. Results A fecundity table of Caenorhabditis briggsae KT0001 fed on S. marcescens SCBI and the control fed on E. coli OP50 is presented. We found no significant difference in survivorship or total fecundity between the S. marcescens SCBI fed and E. coli OP50 fed Caenorhabditis briggsae KT0001. Only the mean onset of reproduction was significantly different between the two groups with E. coli fed C. briggsae maturing earlier (2.12 days than those fed on Serratia (2.42 days. Conclusion S. marcescens SCBI is not highly pathogenic to C. briggsae KT0001 indicating that the entomopathogenicity reported for this association may be beneficial for both the nematode and bacteria. In light of the fact that hitherto conducted experimental tests conform to widely held view that Serratia are highly pathogenic to Caenorhabditis, the absence of a high fitness cost for C. briggsae we report here may indicate that this entomopathogenic association is non-transient suggesting nematode/bacterial associations in the wild may vary greatly. Consequently, broad generalizations about nematode/bacterial associations should be interpreted with care.

  2. Cloning of a Serratia marcescens DNA fragment that induces quinoprotein glucose dehydrogenase-mediated gluconic acid production in Escherichia coli in the presence of stationary phase Serratia marcescens.

    Science.gov (United States)

    Krishnaraj, P U; Goldstein, A H

    2001-12-18

    Serratia marcescens ER2 was isolated from an endorhizosphere sample based on its high level of mineral phosphate solubilizing (MPS) activity. This phenotype was correlated with expression of the direct oxidation pathway. An ER2 plasmid library constructed in Escherichia coli strain DH5alpha was screened for MPS activity. A recombinant clone DH5alpha (pKG3791) was capable of gluconic acid (GA) production and tricalcium phosphate solubilization but only in the presence of stationary phase ER2 cells. GA production in DH5alpha (pKG3791) was apparently the result of the quinoprotein glucose dehydrogenase activity because AG121 (a Tn5 knockout of gcd) carrying pKG3791 did not produce GA under the same conditions. GA production by DH5alpha (pKG3791) was not observed when ER2 was replaced by another PQQ-producing strain bacterium. These data add to a growing body of evidence that E. coli contains some type of PQQ biosynthesis pathway distinct from those previously characterized in Gram-negative bacteria and that these genes may be induced under appropriate conditions.

  3. Carbapenem-resistant Serratia marcescens isolates producing Bush group 2f beta-lactamase (SME-1) in the United States: results from the MYSTIC Programme.

    Science.gov (United States)

    Gales, A C; Biedenbach, D J; Winokur, P; Hacek, D M; Pfaller, M A; Jones, R N

    2001-02-01

    Two carbapenem (imipenem, meropenem)-resistant Serratia marcescens strains were isolated in the United States (Chicago, IL) through the 1999 MYSTIC (Meropenem Yearly Susceptibility Test Information Collection) Programme. The S. marcescens antimicrobial susceptible patterns were: susceptible to ceftriaxone, ceftazidime, and cefepime (MICs, 32 microg/ml) and aztreonam (MIC, > = 16 microg/ml). Each S. marcescens isolate shared an identical epidemiologic type (ribotype and PFGE) and the outer membrane protein profile was also identical to those of the wild type susceptible strains from the same medical center. The PCR utilizing bla(sme-1) primers amplified a gene product that was identified as consistent with SME-1 after DNA sequencing. Imipenem and meropenem resistance due to production of carbapenem-hydrolyzing enzymes among clinical isolates is still very rare, but microbiology laboratories should be aware of these chromosomally encoded enzymes among class C beta-lactamases producing enteric bacilli such as S. marcescens and Enterobacter cloacae.

  4. [Post-antibiotic effect of imipenem, amikacin and ciprofloxacin against various strains of Serratia marcescens].

    Science.gov (United States)

    Bollet, C; Mallet, M N; Bouchemal, H; de Micco, P

    1990-05-01

    The authors compared the post-antibiotic effect (PAE) of imipenem, amikacin, ciprofloxacin, and latamoxef against Serratia marcescens ATCC 13880 (type strain) and against 12 clinical strains belonging to Grimont's most frequent biotypes: A2a, A3a, A3b, A4a, A4b, A5, A6a, A8a, A8b, A8c, TT, TCT. PAE was determined by measuring bacterial growth kinetics after one hour exposure to concentration of 2 x MIC of 10(6) CFUs in Mueller-Hinton broth. Drug removal was by 10-3 dilution of the exposed culture. A PAE was consistently present with imipenem (range 0.8-2.9 hrs), amikacin (range 1.0-4.9 hrs), ciprofloxacin (range 1.4-2.8 hrs). The duration of PAE did not correlate with MIC or Grimont's biotypes.

  5. Brain abscesses after Serratia marcescens infection on a neonatal intensive care unit: differences on serial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Messerschmidt, A.; Olischar, M.; Pollak, A.; Birnbacher, R. [Division of Neonatology and Intensive Care, Department of Paediatrics, University of Vienna, Wahringer Guertel 18-20, 1090, Vienna (Austria); Prayer, D. [Division of Radiology, University of Vienna, Waehringer Guertel 18-20, 1090, Vienna (Austria)

    2004-02-01

    Serratia are known to be a possible cause of severe cerebral infections in neonates. We describe imaging of three premature infants infected with Serratia marcescens. Born in the 31{sup st}, 25{sup th} and 28{sup th} weeks of gestation, they presented with signs of septicaemia on postnatal days 9, 24 and 32. Initial sonography showed cysts in the first child, two areas with anechoic centre and echogenic rim in the second, and several echogenic areas in the third. Lesions were seen on CT, of low density in two cases and minimally increased density in the third. MRI in the first patient showed cysts with incomplete contrast enhancement of the lesions, while patient 2 showed five ring-enhancing fluid-containing lesions with thick walls. In the third patient two abscesses with contrast enhancement and several high-signal spots were seen. We discuss the pathophysiology of the lesions and the impact of the various imaging methods. (orig.)

  6. 粘质沙雷氏菌(Serratia marcescens)的研究Ⅰ-Serratia marcescens 9-2菌株分离、分类鉴定和形态特征%STUDY ON SERRATIA MARCESCENS Ⅰ:THE CHARACTERISTICS OF THE SHAPE,ISOLATION, AND IDENTIFICATION OF SERRATIA MARCESCENS 9-2 STRAIN

    Institute of Scientific and Technical Information of China (English)

    黄文芳

    2003-01-01

    9-2菌株为革兰氏阴性短杆菌,周生鞭毛,菌落红色,经自动微生物鉴定系统(VITECK-AMS-CC2)鉴定9-2菌株为粘质沙雷氏菌(Serratia marcescens),鉴定为99%;9-2菌株对丁氨卡那、强力霉素、复方新诺明、氟哌酸和庆大霉素敏感,对卡那霉素中敏,对呋喃唑酮、头孢唑啉、氯霉素、链霉素、呋喃妥因、红霉素、青霉素G、氨苄青霉素和四环素不敏感;能产生灵杆菌素.

  7. KPC-PRODUCING Serratia marcescens IN A HOME-CARE PATIENT FROM RECIFE, BRAZIL

    Science.gov (United States)

    MARGATE, Emmily; MAGALHÃES, Vera; FEHLBERG, Lorena Cristina Corrêa; GALES, Ana Cristina; LOPES, Ana Catarina Souza

    2015-01-01

    SUMMARY In this brief communication we describe the occurrence of a KPC-producing Serratia marcescensisolate in a home-care patient from Recife, Brazil. The bla KPC, bla SPM, bla IMP, bla VIM bla OXA, bla CTX-M, bla SHV, bla TEM and bla GES genes were investigated by Polymerase Chain Reaction (PCR) and DNA sequencing. The isolate was positive for bla KPC-2 and bla TEM-1 and was resistant to aztreonam, cefepime, cefotaxime, imipenem, meropenem, gentamicin, ciprofloxacin and cefazidime, and susceptible only to amikacin, tigecycline and gatifloxacin. This is the first report in Brazil of KPC-producing S. marcescens clinical isolate outside of a hospital environment. Caregivers should be alert for the presence of this isolate in the community setting. PMID:26422164

  8. KPC-PRODUCING Serratia marcescens IN A HOME-CARE PATIENT FROM RECIFE, BRAZIL

    Directory of Open Access Journals (Sweden)

    Emmily MARGATE

    2015-08-01

    Full Text Available SUMMARY In this brief communication we describe the occurrence of a KPC-producing Serratia marcescensisolate in a home-care patient from Recife, Brazil. The blaKPC, blaSPM, blaIMP, blaVIMblaOXA, blaCTX-M, blaSHV, blaTEM and blaGES genes were investigated by Polymerase Chain Reaction (PCR and DNA sequencing. The isolate was positive for blaKPC-2 and blaTEM-1 and was resistant to aztreonam, cefepime, cefotaxime, imipenem, meropenem, gentamicin, ciprofloxacin and cefazidime, and susceptible only to amikacin, tigecycline and gatifloxacin. This is the first report in Brazil of KPC-producing S. marcescens clinical isolate outside of a hospital environment. Caregivers should be alert for the presence of this isolate in the community setting.

  9. Cefepime shows good efficacy and no antibiotic resistance in pneumonia caused by Serratia marcescens and Proteus mirabilis - an observational study.

    Science.gov (United States)

    Yayan, Josef; Ghebremedhin, Beniam; Rasche, Kurt

    2016-03-23

    Many antibiotics have no effect on Gram-positive and Gram-negative microbes, which necessitates the prescription of broad-spectrum antimicrobial agents that can lead to increased risk of antibiotic resistance. These pathogens constitute a further threat because they are also resistant to numerous beta-lactam antibiotics, as well as other antibiotic groups. This study retrospectively investigates antimicrobial resistance in hospitalized patients suffering from pneumonia triggered by Gram-negative Serratia marcescens or Proteus mirabilis. The demographic and clinical data analyzed in this study were obtained from the clinical databank of the HELIOS Clinic, Witten/Herdecke University, Wuppertal, Germany, for inpatients presenting with pneumonia triggered by S. marcescens or P. mirabilis from 2004 to 2014. An antibiogram was conducted for the antibiotics utilized as part of the management of patients with pneumonia triggered by these two pathogens. Pneumonia was caused by Gram-negative bacteria in 115 patients during the study period from January 1, 2004, to August 12, 2014. Of these, 43 (37.4 %) hospitalized patients [26 males (60.5 %, 95 % CI 45.9 %-75.1 %) and 17 females (39.5 %, 95 % CI 24.9 %-54.1 %)] with mean age of 66.2 ± 13.4 years had pneumonia triggered by S. marcescens, while 20 (17.4 %) patients [14 males (70 %, 95 % CI 49.9 %-90.1 %) and 6 females (30 %, 95 % CI 9.9 %-50.1 %)] with a mean age of 64.6 ± 12.8 years had pneumonia caused by P. mirabilis. S. marcescens showed an increased antibiotic resistance to ampicillin (100 %), ampicillin-sulbactam (100 %), and cefuroxime (100 %). P. mirabilis had a high resistance to tetracycline (100 %) and ampicillin (55 %). S. marcescens (P resistance to cefepime in these patients with pneumonia. S. marcescens and P. mirabilis were resistant to several commonly used antimicrobial agents, but showed no resistance to cefepime.

  10. Fractional Echoes

    CERN Document Server

    Karras, G; Billard, F; Lavorel, B; Siour, G; Hartmann, J -M; Faucher, O; Gershnabel, Erez; Prior, Yehiam; Averbukh, Ilya Sh

    2016-01-01

    We report the observation of fractional echoes in a double-pulse excited nonlinear system. Unlike standard echoes which appear periodically at delays which are integer multiple of the delay between the two exciting pulses, the fractional echoes appear at rational fractions of this delay. We discuss the mechanism leading to this phenomenon, and provide the first experimental demonstration of fractional echoes by measuring third harmonic generation in a thermal gas of CO2 molecules excited by a pair of femtosecond laser pulses.

  11. FRACTIONAL BANKING

    OpenAIRE

    Maria Klimikova

    2010-01-01

    Understanding the reasons of the present financial problems lies In understanding the substance of fractional reserve banking. The substance of fractional banking is in lending more money than the bankers have. Banking of partial reserves is an alternative form which links deposit banking and credit banking. Fractional banking is causing many unfavorable economic impacts in the worldwide system, specifically an inflation.

  12. FRACTIONAL BANKING

    OpenAIRE

    Maria Klimikova

    2010-01-01

    Understanding the reasons of the present financial problems lies In understanding the substance of fractional reserve banking. The substance of fractional banking is in lending more money than the bankers have. Banking of partial reserves is an alternative form which links deposit banking and credit banking. Fractional banking is causing many unfavorable economic impacts in the worldwide system, specifically an inflation.

  13. Fractional randomness

    Science.gov (United States)

    Tapiero, Charles S.; Vallois, Pierre

    2016-11-01

    The premise of this paper is that a fractional probability distribution is based on fractional operators and the fractional (Hurst) index used that alters the classical setting of random variables. For example, a random variable defined by its density function might not have a fractional density function defined in its conventional sense. Practically, it implies that a distribution's granularity defined by a fractional kernel may have properties that differ due to the fractional index used and the fractional calculus applied to define it. The purpose of this paper is to consider an application of fractional calculus to define the fractional density function of a random variable. In addition, we provide and prove a number of results, defining the functional forms of these distributions as well as their existence. In particular, we define fractional probability distributions for increasing and decreasing functions that are right continuous. Examples are used to motivate the usefulness of a statistical approach to fractional calculus and its application to economic and financial problems. In conclusion, this paper is a preliminary attempt to construct statistical fractional models. Due to the breadth and the extent of such problems, this paper may be considered as an initial attempt to do so.

  14. Chromate Reduction in Serratia marcescens Isolated from Tannery Effluent and Potential Application for Bioremediation of Chromate Pollution

    Directory of Open Access Journals (Sweden)

    M.A. Mondaca

    2002-01-01

    Full Text Available Pollution of aquatic systems by heavy metals has resulted in increasing environmental concern because they cannot be biodegraded. One metal that gives reason for concern due to its toxicity is chromium. Cr(VI and Cr(III are the principal forms of chromium found in natural waters. A chromate-resistant strain of the bacterium S. marcescens was isolated from tannery effluent. The strain was able to reduce Cr(VI to Cr(III, and about 80% of chromate was removed from the medium. The reduction seems to occur on the cell surface. Transmission electron microscopic examination of cells revealed that particles were deposited on the outside of bacterial cells. A stable biofilm was formed in less than 10 h, reaching around 1010 cfu attached per milligram of activated carbon. These findings demonstrate that immobilized S. marcescens might be used in industrial waste treatment processes.

  15. Serratia marcescens-contaminated baby shampoo causing an outbreak among newborns at King Abdulaziz University Hospital, Jeddah, Saudi Arabia.

    Science.gov (United States)

    Madani, T A; Alsaedi, S; James, L; Eldeek, B S; Jiman-Fatani, A A; Alawi, M M; Marwan, D; Cudal, M; Macapagal, M; Bahlas, R; Farouq, M

    2011-05-01

    During November 2008 to January 2009, 11 babies in the neonatal intensive care (NICU) and three babies in the nursery were infected with Serratia marcescens at King Abdulaziz University Hospital in Saudi Arabia. Overall, fifteen infections were identified among 11 newborns in the NICU: septicaemia (five cases), purulent conjunctivitis (three), urinary tract infection (two), meningitis (two) and cellulitis (one). Three newborns in the nursery had three infections: purulent conjunctivitis (two cases) and omphalitis (one). Thirteen of 14 babies recovered fully but one died from S. marcescens meningitis and septicaemia. All infections were traced to intrinsically contaminated baby shampoo introduced to the units five days before the first reported case. The outbreak terminated following withdrawal of the shampoo product.

  16. Biodegradation and bioremediation potential of diazinon-degrading Serratia marcescens to remove other organophosphorus pesticides from soils.

    Science.gov (United States)

    Cycoń, Mariusz; Żmijowska, Agnieszka; Wójcik, Marcin; Piotrowska-Seget, Zofia

    2013-03-15

    The ability of diazinon-degrading Serratia marcescens to remove organophosphorus pesticides (OPPs), i.e. chlorpyrifos (CP), fenitrothion (FT), and parathion (PT) was studied in a mineral salt medium (MSM) and in three soils of different characteristics. This strain was capable of using all insecticides at concentration of 50 mg/l as the only carbon source when grown in MSM, and 58.9%, 70.5%, and 82.5% of the initial dosage of CP, FT, and PT, respectively was degraded within 14 days. The biodegradation experiment showed that autochthonous microflora in all soils was characterized by a degradation potential of all tested OPPs; however, the initial lag phases for degradation of CP and FT, especially in sandy soil, were observed. During the 42-day experiment, 45.3%, 61.4% and 72.5% of the initial dose of CP, FT, and PT, respectively, was removed in sandy soil whereas the degradation of CP, FT, and PT in the same period, in sandy loam and silty soils reached 61.4%, 79.7% and 64.2%, and 68.9%, 81.0% and 63.6%, respectively. S. marcescens introduced into sterile soils showed a higher degradation potential (5-13%) for OPPs removal than those observed in non-sterile soil with naturally occurring attenuation. Inoculation of non-sterile soils with S. marcescens enhanced the disappearance rates of all insecticides, and DT50 for CP, FT, and PT was reduced by 20.7, 11.3 and 13.0 days, and 11.9, 7.0 and 8.1 days, and 9.7, 14.5 and 12.6 days in sandy, sandy loam, and silty soils, respectively, in comparison with non-sterile soils with only indigenous microflora. This ability of S. marcescens makes it a suitable strain for bioremediation of soils contaminated with OPPs.

  17. SME-3, a novel member of the Serratia marcescens SME family of carbapenem-hydrolyzing beta-lactamases.

    Science.gov (United States)

    Queenan, Anne Marie; Shang, Wenchi; Schreckenberger, Paul; Lolans, Karen; Bush, Karen; Quinn, John

    2006-10-01

    Imipenem-resistant Serratia marcescens isolates were cultured from a lung transplant patient given multiple antibiotics over several months. The strains expressed SME-3, a beta-lactamase of the rare SME carbapenem-hydrolyzing family. SME-3 differed from SME-1 by a single amino acid substitution of tyrosine for histidine at position 105, but the two beta-lactamases displayed similar hydrolytic profiles.

  18. Characterization of the mineral phosphate solubilizing activity of Serratia marcescens CTM 50650 isolated from the phosphate mine of Gafsa.

    Science.gov (United States)

    Ben Farhat, Mounira; Farhat, Ameny; Bejar, Wacim; Kammoun, Radhouan; Bouchaala, Kameleddine; Fourati, Amin; Antoun, Hani; Bejar, Samir; Chouayekh, Hichem

    2009-11-01

    The mineral phosphate solubilizing (MPS) ability of a Serratia marcescens strain, namely CTM 50650, isolated from the phosphate mine of Gafsa, was characterized on a chemically defined medium (NBRIP broth). Various insoluble inorganic phosphates, including rock phosphate (RP), calcium phosphate (CaHPO(4)), tri-calcium phosphate (Ca(3)(PO(4))(2)) and hydroxyapatite were tested as sole sources of phosphate for bacterial growth. Solubilization of these phosphates by S. marcescens CTM 50650 was very efficient. Indeed, under optimal conditions, the soluble phosphorus (P) concentration it produced reached 967, 500, 595 and 326 mg/l from CaHPO(4), Ca(3)(PO(4))(2), hydroxyapatite and RP, respectively. Study of the mechanisms involved in the MPS activity of CTM 50650, showed that phosphate solubilization was concomitant with significant drop in pH. HPLC-analysis of culture supernatants revealed the secretion of gluconic acid (GA) resulting from direct oxidation pathway of glucose when the CTM 50650 cells were grown on NBRIP containing glucose as unique carbon source. This was correlated with the simultaneous detection by PCR for the first time in a S. marcescens strain producing GA, of a gene encoding glucose dehydrogenase responsible for GA production, as well as the genes pqqA, B, C and E involved in biosynthesis of its PQQ cofactor. This study is expected to lead to the development of an environmental-friendly process for fertilizer production considering the capacity of S. marcescens CTM 50650 to achieve yields of P extraction up to 75% from the Gafsa RP.

  19. Fractional thermoelasticity

    CERN Document Server

    Povstenko, Yuriy

    2015-01-01

    This book is devoted to fractional thermoelasticity, i.e. thermoelasticity based on the heat conduction equation with differential operators of fractional order. Readers will discover how time-fractional differential operators describe memory effects and space-fractional differential operators deal with the long-range interaction. Fractional calculus, generalized Fourier law, axisymmetric and central symmetric problems and many relevant equations are featured in the book. The latest developments in the field are included and the reader is brought up to date with current research.  The book contains a large number of figures, to show the characteristic features of temperature and stress distributions and to represent the whole spectrum of order of fractional operators.  This work presents a picture of the state-of-the-art of fractional thermoelasticity and is suitable for specialists in applied mathematics, physics, geophysics, elasticity, thermoelasticity and engineering sciences. Corresponding sections of ...

  20. Anti-biofilm potential of a glycolipid surfactant produced by a tropical marine strain of Serratia marcescens.

    Science.gov (United States)

    Dusane, Devendra H; Pawar, Vinay S; Nancharaiah, Y V; Venugopalan, V P; Kumar, Ameeta Ravi; Zinjarde, Smita S

    2011-01-01

    A tropical marine bacterium isolated from the hard coral, Symphyllia sp. was identified as Serratia marcescens on the basis of morphological, biochemical and 16S rDNA analysis. The bacterium showed antimicrobial activity towards the pathogens Candida albicans and Pseudomonas aeruginosa and the marine biofouling bacterium Bacillus pumilus. S. marcescens displayed biosurfactant activity as evidenced by drop collapse, blood hemolysis and surface tension reduction (52.0-27 mN m(-1)). The active compound was purified by solvent extraction and silicic acid chromatography. Characterization was by thin layer chromatography, gas chromatography mass spectroscopy (GC-MS), Fourier transform infrared (FTIR) spectroscopy and (1)H as well as (13)C nuclear magnetic resonance (NMR) analysis. The surfactant was found to be a glycolipid composed of glucose and palmitic acid. The glycolipid prevented adhesion of C. albicans BH, P. aeruginosa PAO1 and B. pumilus TiO1. The glycolipid also disrupted preformed biofilms of these cultures in microtitre plates. Confocal laser scanning microscopy and electron microscopy confirmed the effective removal of biofilms from glass surfaces. The glycolipid derived from S. marcescens could thus serve as a potential anti-biofilm agent.

  1. Role of the phosphopantetheinyltransferase enzyme, PswP, in the biosynthesis of antimicrobial secondary metabolites by Serratia marcescens Db10.

    Science.gov (United States)

    Gerc, Amy J; Stanley-Wall, Nicola R; Coulthurst, Sarah J

    2014-08-01

    Phosphopantetheinyltransferase (PPTase) enzymes fulfil essential roles in primary and secondary metabolism in prokaryotes, archaea and eukaryotes. PPTase enzymes catalyse the essential modification of the carrier protein domain of fatty acid synthases, polyketide synthases (PKSs) and non-ribosomal peptide synthetases (NRPSs). In bacteria and fungi, NRPS and PKS enzymes are often responsible for the biosynthesis of secondary metabolites with clinically relevant properties; these secondary metabolites include a variety of antimicrobial peptides. We have previously shown that in the Gram-negative bacterium Serratia marcescens Db10, the PPTase enzyme PswP is essential for the biosynthesis of an NRPS-PKS dependent antibiotic called althiomycin. In this work we utilize bioinformatic analyses to classify PswP as belonging to the F/KES subfamily of Sfp type PPTases and to putatively identify additional NRPS substrates of PswP, in addition to the althiomycin NRPS-PKS, in Ser. marcescens Db10. We show that PswP is required for the production of three diffusible metabolites by this organism, each possessing antimicrobial activity against Staphylococcus aureus. Genetic analyses identify the three metabolites as althiomycin, serrawettin W2 and an as-yet-uncharacterized siderophore, which may be related to enterobactin. Our results highlight the use of an individual PPTase enzyme in multiple biosynthetic pathways, each contributing to the ability of Ser. marcescens to inhibit competitor bacteria by the production of antimicrobial secondary metabolites.

  2. Risk factors for extended-spectrum beta-lactamase-producing Serratia marcescens and Klebsiella pneumoniae acquisition in a neonatal intensive care unit.

    Science.gov (United States)

    Crivaro, V; Bagattini, M; Salza, M F; Raimondi, F; Rossano, F; Triassi, M; Zarrilli, R

    2007-10-01

    We investigated the molecular epidemiology of gentamicin-resistant, extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and Serratia marcescens, and risk factors associated with their acquisition in a neonatal intensive care unit (NICU) of a university hospital in Italy. During the study period (April-November 2004), S. marcescens was responsible for six infections and 31 colonisations, while K. pneumoniae was responsible for six infections and 103 colonisations. Concurrent isolation of both organisms occurred in 24 neonates. Molecular typing identified one major pulsed-field gel electrophoresis pattern each for S. marcescens and K. pneumoniae strains isolated during the study period. An 80 kb plasmid containing bla(SHV-12), bla(TEM-1) and aac(6')-Ib genes, isolated from both S. marcescens and K. pneumoniae strains, and showing identical restriction profiles, transferred resistance to third-generation cephalosporins to a previously susceptible Escherichia coli host. Birthweight, gestational age and use of invasive devices were significantly associated with S. marcescens and K. pneumoniae acquisition on univariate analysis, while empiric antimicrobial treatment with ampicillin and gentamicin, and duration of hospital stay, proved to be the only independent risk factors. In conclusion, conjugal plasmid transfer and empiric antimicrobial therapy with ampicillin and gentamicin might have contributed to the selection and spread of gentamicin-resistant ESBL-producing Enterobacteriaceae in the NICU.

  3. Biosynthesis of bismuth nanoparticles using Serratia marcescens isolated from the Caspian Sea and their characterisation.

    Science.gov (United States)

    Nazari, P; Faramarzi, M A; Sepehrizadeh, Z; Mofid, M R; Bazaz, R D; Shahverdi, A R

    2012-06-01

    Today, synthesis of nanoparticles (NPs) using micro-organisms has been receiving increasing attention. In this investigation, a bismuth-reducing bacterium was isolated from the Caspian Sea in Northern Iran and was used for intracellular biosynthesis of elemental bismuth NPs. This isolate was identified as non-pigmented Serratia marcescens using conventional identification assays and the 16s rDNA fragment amplification method and used to prepare bismuth NPs. The biogenic bismuth NPs were released by liquid nitrogen and highly purified using an n-octanol water two-phase extraction system. Different characterisations of the purified NPs such as particle shapes, size and purity were carried out with different instruments. The energy-dispersive X-ray and X-ray diffraction (XRD) patterns demonstrated that the purified NPs consisted of only bismuth and are amorphous. In addition, the transmission electron micrograph showed that the small NPs formed larger aggregated NPs around <150 nm. Although the chemical syntheses of elemental bismuth NPs have been reported in the literature, the biological synthesis of elemental bismuth NPs has not been published yet. This is the first report to demonstrate a biological method for synthesising bismuth NPs and their purification with a simple solvent partitioning method.

  4. SOME FEATURES OF HYDROLYSIS OF THE HYBRID B-Z-FORM DNA BY SERRATIA MARCESCENS NUCLEASE

    Directory of Open Access Journals (Sweden)

    Maria Filimonova

    2014-01-01

    Full Text Available Highly polymerized herring testis DNA of the random nucleotide sequence was used as a model of natural substrate to study some features of hydrolysis of the hybrid B-Z form with Serratia marcescens nuclease. The hybrid B-Z-form was formed upon addition of 1.15 M MgSO4 and 0.421 mM Co(NH36Cl3. The DNA transition from the right handed B-form to the hybrid B-Z-form caused a decrease in Vmax of DNA cleavage with the nuclease. The diminishing Vmax was consistent with diminishing values of Km and Kcat. The binding of Mg2+ or Co(NH363+ to highly polymerized DNA caused correspondingly about 80-or 7-fold decrease in Km and more than 1600 or 600 decrease in Kcat compared with that of Mg-DNA complex of B-form.

  5. Influence of incubation temperature on biofilm formation and corrosion of carbon steel by Serratia marcescens

    Science.gov (United States)

    Harimawan, Ardiyan; Devianto, Hary; Kurniawan, Ignatius Chandra; Utomo, Josephine Christine

    2017-01-01

    Microbial induced corrosion (MIC) or biocorrosion is one type of corrosion, directly or indirectly influenced by microbial activities, by forming biofilm and adhering on the metal surface. When forming biofilm, the microorganisms can produce extracellular products which influence the cathodic and anodic reactions on metal surfaces. This will result in electrochemical changes in the interface between the biofilm and the metal surface, leading to corrosion and deterioration of the metal. MIC might be caused by various types of microorganism which leads to different corrosion mechanism and reaction kinetics. Furthermore, this process will also be influenced by various environmental conditions, such as pH and temperature. This research is aimed to determine the effect of incubation temperature on corrosion of carbon steel caused by Serratia marcescens in a mixture solution of synthetic seawater with Luria Bertani medium with a ratio of 4:1. The incubation was performed for 19 days with incubation temperature of 30, 37, and 50°C. The analyses of biofilm were conducted by total plate count (TPC), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Biofilm was found to be evenly growth on the surface and increasing with increasing incubation temperature. It consists of functional group of alcohol, alkane, amine, nitro, sulfate, carboxylic acid, and polysulfide. The analyses of the corrosion were conducted by gravimetric and X-ray diffraction (XRD). Higher incubation temperature was found to increase the corrosion rate. However, the corrosion products were not detected by XRD analysis.

  6. Multigenic natural variation underlies Caenorhabditis elegans olfactory preference for the bacterial pathogen Serratia marcescens.

    Science.gov (United States)

    Glater, Elizabeth E; Rockman, Matthew V; Bargmann, Cornelia I

    2014-02-19

    The nematode Caenorhabditis elegans can use olfaction to discriminate among different kinds of bacteria, its major food source. We asked how natural genetic variation contributes to choice behavior, focusing on differences in olfactory preference behavior between two wild-type C. elegans strains. The laboratory strain N2 strongly prefers the odor of Serratia marcescens, a soil bacterium that is pathogenic to C. elegans, to the odor of Escherichia coli, a commonly used laboratory food source. The divergent Hawaiian strain CB4856 has a weaker attraction to Serratia than the N2 strain, and this behavioral difference has a complex genetic basis. At least three quantitative trait loci (QTLs) from the CB4856 Hawaii strain (HW) with large effect sizes lead to reduced Serratia preference when introgressed into an N2 genetic background. These loci interact and have epistatic interactions with at least two antagonistic QTLs from HW that increase Serratia preference. The complex genetic architecture of this C. elegans trait is reminiscent of the architecture of mammalian metabolic and behavioral traits.

  7. RssAB signaling coordinates early development of surface multicellularity in Serratia marcescens.

    Directory of Open Access Journals (Sweden)

    Yu-Huan Tsai

    Full Text Available Bacteria can coordinate several multicellular behaviors in response to environmental changes. Among these, swarming and biofilm formation have attracted significant attention for their correlation with bacterial pathogenicity. However, little is known about when and where the signaling occurs to trigger either swarming or biofilm formation. We have previously identified an RssAB two-component system involved in the regulation of swarming motility and biofilm formation in Serratia marcescens. Here we monitored the RssAB signaling status within single cells by tracing the location of the translational fusion protein EGFP-RssB following development of swarming or biofilm formation. RssAB signaling is specifically activated before surface migration in swarming development and during the early stage of biofilm formation. The activation results in the release of RssB from its cognate inner membrane sensor kinase, RssA, to the cytoplasm where the downstream gene promoters are located. Such dynamic localization of RssB requires phosphorylation of this regulator. By revealing the temporal activation of RssAB signaling following development of surface multicellular behavior, our findings contribute to an improved understanding of how bacteria coordinate their lifestyle on a surface.

  8. Heterotrophic nitrogen removal by a newly-isolated alkalitolerant microorganism, Serratia marcescens W5.

    Science.gov (United States)

    Wang, Teng; Dang, Qifeng; Liu, Chengsheng; Yan, Jingquan; Fan, Bing; Cha, Dongsu; Yin, Yanyan; Zhang, Yubei

    2016-07-01

    A new microbe, Serratia marcescens W5 was successfully isolated. Its feasibility in purification of excessively nitrogen-containing wastewater was evaluated using inorganic nitrogen media. Single factor tests showed that W5 exhibited high ammonium removal rates (above 80%) under different culture conditions (pH 7-10, C/N ratios of 6-20, 15-35°C, 0-2.5% of salinity, respectively). Besides various organic carbon sources, W5 was able to utilize calcium carbonate with 28.05% of ammonium removed. Further experiments indicated that W5 was capable of resisting high-strength ammonium (1200mg/L) with the maximum removal rate of 514.13mgL(-1)d(-1). The nitrogen removal pathway of W5 was also tested, showing that both nitrite and nitrate were efficiently removed only in the presence of ammonium, with hydroxylamine as intermediate, which was different from the conventional nitrogen removal pathway. All the results verified that W5 was a good candidate for the purification of excessively nitrogenous wastewater.

  9. Degradation of 4-aminophenol by hydrogen peroxide oxidation using enzyme from Serratia marcescens as catalyst

    Institute of Scientific and Technical Information of China (English)

    SUN Min; YAO Risheng; YOU Yahua; DENG Shengsong; GAO Wenxia

    2007-01-01

    This paper reports on the degradation of 4-aminophenol using hydrogen peroxide as oxidizer and the enzyme from Serratia marcescens AB 90027 as catalyst.The effecting factors during degradation and the degrading mechanism were studied.Also,the location of the enzyme in the cell,which could catalyze the degradation of 4-aminophenol,was analyzed.The results showed that to degrade 50 mL of 4-aminophenol whose concentration was 500 mg/L,the optimal conditions were:volume of H2O2=3 mL,temperature=40-60℃ and pH=9-10]In the degradation process,4-aminophenol was first converted to benzo quinone and NH3,then organic acids including maleic acid,fumaleic acid,and oxalic acid were formed,and then finally CO2 and H2O were generated as final products.The enzyme that could catalyze the degradation of 4-aminophenol was mainly extracellular enzyme.

  10. Fractional motions

    Energy Technology Data Exchange (ETDEWEB)

    Eliazar, Iddo I., E-mail: eliazar@post.tau.ac.il [Holon Institute of Technology, P.O. Box 305, Holon 58102 (Israel); Shlesinger, Michael F., E-mail: mike.shlesinger@navy.mil [Office of Naval Research, Code 30, 875 N. Randolph St., Arlington, VA 22203 (United States)

    2013-06-10

    Brownian motion is the archetypal model for random transport processes in science and engineering. Brownian motion displays neither wild fluctuations (the “Noah effect”), nor long-range correlations (the “Joseph effect”). The quintessential model for processes displaying the Noah effect is Lévy motion, the quintessential model for processes displaying the Joseph effect is fractional Brownian motion, and the prototypical model for processes displaying both the Noah and Joseph effects is fractional Lévy motion. In this paper we review these four random-motion models–henceforth termed “fractional motions” –via a unified physical setting that is based on Langevin’s equation, the Einstein–Smoluchowski paradigm, and stochastic scaling limits. The unified setting explains the universal macroscopic emergence of fractional motions, and predicts–according to microscopic-level details–which of the four fractional motions will emerge on the macroscopic level. The statistical properties of fractional motions are classified and parametrized by two exponents—a “Noah exponent” governing their fluctuations, and a “Joseph exponent” governing their dispersions and correlations. This self-contained review provides a concise and cohesive introduction to fractional motions.

  11. Assessment of process parameters influencing the enhanced production of prodigiosin from Serratia marcescens and evaluation of its antimicrobial, antioxidant and dyeing potentials

    Directory of Open Access Journals (Sweden)

    Gulani, C.

    2012-06-01

    Full Text Available Aims: Prodigiosin is a bright red pigment produced by certain strains of Serratia marcescens, characterized by a common pyrrolylpyrromethane skeleton. This pigment is found to possess antibacterial, antifungal, immunosuppressive and antiproliferative activity. The present study aimed at designing process parameters for the enhanced production of this pigment.Methodology and Results: Peptone glycerol broth was selected as the best synthetic medium. The effects of various media components and process parameters like carbon and nitrogen sources, temperature, pH, incubation period and other supplements were investigated. Maximal amount of prodigiosin was produced at temperature 25 °C, pH 7.0 andincubation period of 48 h. Supplementation of media with maltose and peptone yielded maximal amount of prodigiosin. Incorporation of minimal amount of supplements like silica gel, iron salts, inorganic phosphate also showed promising results. Chromatographic separations suggested that prodigiosin is made up of three different fractions (purple, orange and red. Further investigation of antimicrobial properties of prodigiosin revealed that it is a potent inhibitor against gram positive bacteria like Staphylococcus aureus and Bacillus cereus and fungal pathogens like Candida albicans, C.parapsilosis and Cryptococcus sp. This antimicrobial potency remained stable under a wide range of temperature and pH. The antioxidant capacity of prodigiosin was found to be 22.05 Bg ascorbic acid equivalents/ml of extract. When applied to textiles, prodigiosin resisted the action of acid, alkali and detergent. Conclusion, Significance and Impact of study: Besides combating gram positive bacterial pathogens and some pathogenic yeasts, prodigiosin with strong dyeing and antioxidant activity may find broad applications in textile and therapeutic industries.

  12. Conversion of α-chitin substrates with varying particle size and crystallinity reveals substrate preferences of the chitinases and lytic polysaccharide monooxygenase of Serratia marcescens.

    Science.gov (United States)

    Nakagawa, Yuko S; Eijsink, Vincent G H; Totani, Kazuhide; Vaaje-Kolstad, Gustav

    2013-11-20

    Industrial depolymerization of chitinous biomass generally requires numerous steps and the use of deleterious substances. Enzymatic methods provide an alternative, but fundamental knowledge that could direct potential development of industrial enzyme cocktails is scarce. We have studied the contribution of monocomponent chitinases (ChiA, -B, and -C) and the lytic polysaccharide monooxygenase (LPMO) from Serratia marcescens on depolymerization of α-chitin substrates with varying particle size and crystallinity that were generated using a converge mill. For all chitinases activity was positively correlated to a decline in particle size and crystallinity. Especially ChiC, the only nonprocessive endochitinase from the S. marcescens chitinolytic machinery, benefited from mechanical pretreatment. Combining the chitinases revealed clear synergies for all substrates tested. CBP21, the chitin-active LPMO from S. marcescens, increased solubilization of substrates with high degrees of crystallinity when combined with each of the three chitinases, but this synergy was reduced upon decline in crystallinity.

  13. Polymer fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, A. F.

    1985-04-09

    Soluble polymers are fractionated according to molecular weight by cryogenically comminuting the polymer and introducing the polymer particles, while still in the active state induced by cryogenic grinding, into a liquid having a solvent power selected to produce a coacervate fraction containing high molecular weight polymer species and a dilute polymer solution containing lower molecular weight polymer species. The coacervate may be physically separated from the solution and finds use in the production of antimisting jet fuels and the like.

  14. SME-type carbapenem-hydrolyzing class A beta-lactamases from geographically diverse Serratia marcescens strains.

    Science.gov (United States)

    Queenan, A M; Torres-Viera, C; Gold, H S; Carmeli, Y; Eliopoulos, G M; Moellering, R C; Quinn, J P; Hindler, J; Medeiros, A A; Bush, K

    2000-11-01

    Three sets of carbapenem-resistant Serratia marcescens isolates have been identified in the United States: 1 isolate in Minnesota in 1985 (before approval of carbapenems for clinical use), 5 isolates in Los Angeles (University of California at Los Angeles [UCLA]) in 1992, and 19 isolates in Boston from 1994 to 1999. All isolates tested produced two beta-lactamases, an AmpC-type enzyme with pI values of 8.6 to 9.0 and one with a pI value of approximately 9.5. The enzyme with the higher pI in each strain hydrolyzed carbapenems and was not inhibited by EDTA, similar to the chromosomal class A SME-1 beta-lactamase isolated from the 1982 London strain S. marcescens S6. The genes encoding the carbapenem-hydrolyzing enzymes were cloned in Escherichia coli and sequenced. The enzyme from the Minnesota isolate had an amino acid sequence identical to that of SME-1. The isolates from Boston and UCLA produced SME-2, an enzyme with a single amino acid change relative to SME-1, a substitution from valine to glutamine at position 207. Purified SME enzymes from the U. S. isolates had beta-lactam hydrolysis profiles similar to that of the London SME-1 enzyme. Pulsed-field gel electrophoresis analysis revealed that the isolates showed some similarity but differed by at least three genetic events. In conclusion, a family of rare class A carbapenem-hydrolyzing beta-lactamases first described in London has now been identified in S. marcescens isolates across the United States.

  15. Understanding Multiplication of Fractions.

    Science.gov (United States)

    Sweetland, Robert D.

    1984-01-01

    Discussed the use of Cuisenaire rods in teaching the multiplication of fractions. Considers whole number times proper fraction, proper fraction multiplied by proper fraction, mixed number times proper fraction, and mixed fraction multiplied by mixed fractions. (JN)

  16. Biodegradation of diazinon by Serratia marcescens DI101 and its use in bioremediation of contaminated environment.

    Science.gov (United States)

    Abo-Amer, Aly

    2011-01-01

    Four diazinon-degrading bacteria were isolated from agricultural soil by using an enrichment technique. The biochemical analysis and molecular method including RFLP indicated that these isolates were identical, and one strain designated DI101 was selected for further study. Phylogenetic analysis based on 16S rDNA sequencing indicated that the strain DI101 clearly belongs to the Serratia marcescens group. The ability of the strain to utilize diazinon as a source of carbon and phosphorus was investigated under different culture conditions. The DI101 strain was able to completely degrade 50 mg/l diazinon in MSM within 11 days with a degradation rate of 0.226 day-1. The inoculation of sterilized soil treated with 100 mg/kg of diazinon with 10(6) CFU/g DI101 resulted in a faster degradation rate than was recorded in non-sterilized soil. The diazinon degradation rate by DI101 was efficient at temperatures from 25 to 30degrees C and at pHs from 7.0 to 8.0. The degradation rate of diazinon was not affected by the absence of a phosphorus supplement, and addition of other carbon sources (glucose or succinate) resulted in the slowing down of the degradation rate. The maximum degradation rate (Vmax) of diazinon was 0.292 day-1 and its saturation constant (Ks) was 11 mg/l, as determined by a Michaelis-Menten curve. The strain was able to degrade diethylthiophosphate-containing organophosphates such as chlorpyrifos, coumaphos, parathion, and isazofos when provided as a source of carbon and phosphorus, but not ethoprophos, cadusafos, and fenamiphos. These results propose useful information for the potential application of the DI101 strain in bioremediation of pesticide-contaminated environments.

  17. Kinetics of mercury reduction by Serratia marcescens mercuric reductase expressed by pseudomonas putida strains

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M.; Deckwer, W.D. [GBF-Gesellschaft fuer Biotechnologische Forschung mbH, Abteilung TU-BCE, Mascheroder Weg 1, D-38124 Braunschweig (Germany)

    2005-10-01

    Mercury (Hg) resistance is widespread among microorganisms and is based on the intracellular transformation of Hg(II) to less toxic elemental Hg(0). The use of microbial consortia to demercurize polluted wastewater streams and environments has been demonstrated. To develop efficient and versatile microbial cleanup strategies requires detailed knowledge of transport and reaction rates. This study focuses on the kinetics of the key enzyme of the microbial transformation, e.g., the mercuric reductase (MerA) under conditions closely resembling the cell interior. To this end, previously constructed and characterized Pseudomonas putida strains expressing MerA from Serratia marcescens were applied. Of the P. putida strains considered in this study P. putida KT2442::mer73 constitutively expressing broad spectrum mercury resistance (merTPAB) yielded the highest mercuric reductase (MerA) activity directly after cell disruption. MerA in the raw extract was further purified (about 100 fold). Reduction rates were measured for various substrates (HgCl{sub 2}, Hg{sub 2}SO{sub 4}, Hg(NO{sub 3}){sub 2} and phenyl mercury acetate) up to high concentrations dependent on the purification grade. In all cases, a pronounced substrate inhibition was found. The kinetic constants determined for the cell raw extract are in agreement with those measured for intact cells. However, the rate data exhibit reduced affinity and inhibition with rising purification grade (specific activity). Therefore, the findings seemingly point to reactions preceding the catalytic reduction. Based on simplified assumptions, a kinetic model is suggested which reasonably describes the experimental findings and can advantageously be applied to the bioreactor design. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  18. Genetic dissection of Anopheles gambiae gut epithelial responses to Serratia marcescens.

    Directory of Open Access Journals (Sweden)

    Stavros Stathopoulos

    2014-03-01

    Full Text Available Genetic variation in the mosquito Anopheles gambiae profoundly influences its ability to transmit malaria. Mosquito gut bacteria are shown to influence the outcome of infections with Plasmodium parasites and are also thought to exert a strong drive on genetic variation through natural selection; however, a link between antibacterial effects and genetic variation is yet to emerge. Here, we combined SNP genotyping and expression profiling with phenotypic analyses of candidate genes by RNAi-mediated silencing and 454 pyrosequencing to investigate this intricate biological system. We identified 138 An. gambiae genes to be genetically associated with the outcome of Serratia marcescens infection, including the peptidoglycan recognition receptor PGRPLC that triggers activation of the antibacterial IMD/REL2 pathway and the epidermal growth factor receptor EGFR. Silencing of three genes encoding type III fibronectin domain proteins (FN3Ds increased the Serratia load and altered the gut microbiota composition in favor of Enterobacteriaceae. These data suggest that natural genetic variation in immune-related genes can shape the bacterial population structure of the mosquito gut with high specificity. Importantly, FN3D2 encodes a homolog of the hypervariable pattern recognition receptor Dscam, suggesting that pathogen-specific recognition may involve a broader family of immune factors. Additionally, we showed that silencing the gene encoding the gustatory receptor Gr9 that is also associated with the Serratia infection phenotype drastically increased Serratia levels. The Gr9 antibacterial activity appears to be related to mosquito feeding behavior and to mostly rely on changes of neuropeptide F expression, together suggesting a behavioral immune response following Serratia infection. Our findings reveal that the mosquito response to oral Serratia infection comprises both an epithelial and a behavioral immune component.

  19. Secretion and activation of the Serratia marcescens hemolysin by structurally defined ShlB mutants.

    Science.gov (United States)

    Pramanik, Avijit; Könninger, Ulrich; Selvam, Arun; Braun, Volkmar

    2014-05-01

    The ShlA hemolysin of Serratia marcescens is secreted across the outer membrane by the ShlB protein; ShlB belongs to the two-partner secretion system (type Vb), a subfamily of the Omp85 outer membrane protein assembly and secretion superfamily. During secretion, ShlA is converted from an inactive non-hemolytic form into an active hemolytic form. The structure of ShlB is predicted to consist of the N-terminal α-helix H1, followed by the two polypeptide-transport-associated domains POTRA P1 and P2, and the β-barrel of 16 β-strands. H1 is inserted into the pore of the β-barrel in the outer membrane; P1 and P2 are located in the periplasm. To obtain insights into the secretion and activation of ShlA by ShlB, we isolated ShlB mutants impaired in secretion and/or activation. The triple H1 P1 P2 mutant did not secrete ShlA. The P1 and P2 deletion derivatives secreted reduced amounts of ShlA, of which P1 showed some hemolysis, whereas P2 was inactive. Deletion of loop 6 (L6), which is conserved among exporters of the Omp85 family, compromised activation but retained low secretion. Secretion-negative mutants generated by random mutagenesis were located in loop 6. The inactive secreted ShlA derivatives were complemented in vitro to active ShlA by an N-terminal ShlA fragment (ShlA242) secreted by ShlB. Deletion of H1 did not impair secretion of hemolytic ShlA. The study defines domains of ShlB which are important for ShlA secretion and activation.

  20. Structure of the imipenem-hydrolyzing class A beta-lactamase SME-1 from Serratia marcescens.

    Science.gov (United States)

    Sougakoff, Wladimir; L'Hermite, Guillaume; Pernot, Lucile; Naas, Thierry; Guillet, Valérie; Nordmann, Patrice; Jarlier, Vincent; Delettré, Jean

    2002-02-01

    The structure of the beta-lactamase SME-1 from Serratia marcescens, a class A enzyme characterized by its significant activity against imipenem, has been determined to 2.13 A resolution. The overall structure of SME-1 is similar to that of other class A beta-lactamases. In the active-site cavity, most of the residues found in SME-1 are conserved among class A beta-lactamases, except at positions 104, 105 and 237, where a tyrosine, a histidine and a serine are found, respectively, and at position 238, which is occupied by a cysteine forming a disulfide bridge with the other cysteine residue located at position 69. The crucial role played by this disulfide bridge in SME-1 was confirmed by site-directed mutagenesis of Cys69 to Ala, which resulted in a mutant unable to confer resistance to imipenem and all other beta-lactam antibiotics tested. Another striking structural feature found in SME-1 was the short distance separating the side chains of the active serine residue at position 70 and the strictly conserved glutamate at position 166, which is up to 1.4 A shorter in SME-1 compared with other class A beta-lactamases. Consequently, the SME-1 structure cannot accommodate the essential catalytic water molecule found between Ser70 and Glu166 in the other class A beta-lactamases described so far, suggesting that a significant conformational change may be necessary in SME-1 to properly position the hydrolytic water molecule involved in the hydrolysis of the acyl-enzyme intermediate.

  1. Characterization of a chitinase with antifungal activity from a native Serratia marcescens B4A

    Directory of Open Access Journals (Sweden)

    Mandana Zarei

    2011-09-01

    Full Text Available Chitinases have the ability of chitin digestion that constitutes a main compound of the cell wall in many of the phytopathogens such as fungi. In the following investigation, a novel chitinase with antifungal activity was characterized from a native Serratia marcescens B4A. Partially purified enzyme had an apparent molecular mass of 54 kDa. It indicated an optimum activity in pH 5 at 45ºC. Enzyme was stable in 55ºC for 20 min and at a pH range of 3-9 for 90 min at 25ºC. When the temperature was raised to 60ºC, it might affect the structure of enzymes lead to reduction of chitinase activity. Moreover, the Km and Vmax values for chitin were 8.3 mg/ml and 2.4 mmol/min, respectively. Additionally, the effect of some cations and chemical compounds were found to stimulate the chitinase activity. In addition, Iodoacetamide and Idoacetic acid did not inhibit enzyme activity, indicating that cysteine residues are not part of the catalytic site of chitinase. Finally, chitinase activity was further monitored by scanning electronic microscopy data in which progressive changes in chitin porosity appeared upon treatment with chitinase. This enzyme exhibited antifungal activity against Rhizoctonia solani, Bipolaris sp, Alternaria raphani, Alternaria brassicicola, revealing a potential application for the industry with potentially exploitable significance. Fungal chitin shows some special features, in particular with respect to chemical structure. Difference in chitinolytic ability must result from the subsite structure in the enzyme binding cleft. This implies that why the enzyme didn't have significant antifungal activity against other Fungi.

  2. Antagonism of Serratia marcescens towards Phytophthora parasitica and its effects in promoting the growth of citrus Antagonismo de Serratia marcescens contra Phytophthora parasitica e seu efeito na promoção do crescimentos de citros

    Directory of Open Access Journals (Sweden)

    Brigida Pimentel Villar de Queiroz

    2006-12-01

    Full Text Available Phytophthora parasitica causes serious widespread, and difficult-to-control root rots in warmer regions. This oomycete is one of the most important pathogen of citrus. This paper reports the biological control of the pathogen by a strain of Serratia marcescens R-35, isolated from citrus rhizosphere. In greenhouse trials, the bacterium suppressed more than 50% of the disease and promoted the plant growth.Phytophthora parasitica é um oomiceto que causa sérios problemas fitossanitários em diferentes espécies de plantas em regiões tropicais e o controle tem sido difícil. Este patógeno é um dos mais importante à citricultura. Este trabalho relata o controle biológico do patógeno por uma linhagem de Serratia marcescens R-35, isolada da rizosfera de citros. Em condições de casa-de-vegetação, a bactéria reduziu em mais de 50% a incidência da doença, ao mesmo tempo que promoveu o crescimento de plantas.

  3. Mystery Fractions

    Science.gov (United States)

    Bhattacharyya, Sonalee; Namakshi, Nama; Zunker, Christina; Warshauer, Hiroko K.; Warshauer, Max

    2016-01-01

    Making math more engaging for students is a challenge that every teacher faces on a daily basis. These authors write that they are constantly searching for rich problem-solving tasks that cover the necessary content, develop critical-thinking skills, and engage student interest. The Mystery Fraction activity provided here focuses on a key number…

  4. Mystery Fractions

    Science.gov (United States)

    Bhattacharyya, Sonalee; Namakshi, Nama; Zunker, Christina; Warshauer, Hiroko K.; Warshauer, Max

    2016-01-01

    Making math more engaging for students is a challenge that every teacher faces on a daily basis. These authors write that they are constantly searching for rich problem-solving tasks that cover the necessary content, develop critical-thinking skills, and engage student interest. The Mystery Fraction activity provided here focuses on a key number…

  5. Modulation of Quorum Sensing in Acylhomoserine Lactone-Producing or -Degrading Tobacco Plants Leads to Alteration of Induced Systemic Resistance Elicited by the Rhizobacterium Serratia marcescens 90-166.

    Science.gov (United States)

    Ryu, Choong-Min; Choi, Hye Kyung; Lee, Chi-Ho; Murphy, John F; Lee, Jung-Kee; Kloepper, Joseph W

    2013-06-01

    Numerous root-associated bacteria (rhizobacteria) are known to elicit induced systemic resistance (ISR) in plants. Bacterial cell-density-dependent quorum sensing (QS) is thought to be important for ISR. Here, we investigated the role of QS in the ISR elicited by the rhizobacterium, Serratia marcescens strain 90-166, in tobacco. Since S. marcescens 90-166 produces at least three QS signals, QS-mediated ISR in strain 90-166 has been difficult to understand. Therefore, we investigated the ISR capacity of two transgenic tobacco (Nicotiana tabacum) plants that contained either bacterial acylhomoserine lactone-producing (AHL) or -degrading (AiiA) genes in conjunction with S. marcescens 90-166 to induce resistance against bacterial and viral pathogens. Root application of S. marcescens 90-166 increased ISR to the bacterial pathogens, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas syringae pv. tabaci, in AHL plants and decreased ISR in AiiA plants. In contrast, ISR to Cucumber mosaic virus was reduced in AHL plants treated with S. marcescens 90-166 but enhanced in AiiA plants. Taken together, these data indicate that QS-dependent ISR is elicited by S. marcescens 90-166 in a pathogen-dependent manner. This study provides insight into QS-dependent ISR in tobacco elicited by S. marcescens 90-166.

  6. Modulation of Quorum Sensing in Acylhomoserine Lactone-Producing or -Degrading Tobacco Plants Leads to Alteration of Induced Systemic Resistance Elicited by the Rhizobacterium Serratia marcescens 90-166

    Directory of Open Access Journals (Sweden)

    Choong-Min Ryu

    2013-06-01

    Full Text Available Numerous root-associated bacteria (rhizobacteria are known to elicit induced systemic resistance (ISR in plants. Bacterial cell-density-dependent quorum sensing (QS is thought to be important for ISR. Here, we investigated the role of QS in the ISR elicited by the rhizobacterium, Serratia marcescens strain 90–166, in tobacco. Since S. marcescens 90–166 produces at least three QS signals, QS-mediated ISR in strain 90–166 has been difficult to understand. Therefore, we investigated the ISR capacity of two transgenic tobacco (Nicotiana tabacum plants that contained either bacterial acylhomoserine lactone-producing (AHL or -degrading (AiiA genes in conjunction with S. marcescens 90–166 to induce resistance against bacterial and viral pathogens. Root application of S. marcescens 90–166 increased ISR to the bacterial pathogens, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas syringae pv. tabaci, in AHL plants and decreased ISR in AiiA plants. In contrast, ISR to Cucumber mosaic virus was reduced in AHL plants treated with S. marcescens 90–166 but enhanced in AiiA plants. Taken together, these data indicate that QS-dependent ISR is elicited by S. marcescens 90–166 in a pathogen-dependent manner. This study provides insight into QS-dependent ISR in tobacco elicited by S. marcescens 90–166.

  7. Isolation and identiifcation of Serratia marcescens Ha1 and herbicidal activity of Ha1‘pesta’ granular formulation

    Institute of Scientific and Technical Information of China (English)

    YANG Juan; WANG Wei; YANG Peng; TAO Bu; YANG Zheng; ZHANG Li-hui; DONG Jin-gao

    2015-01-01

    A total of 479 bacterial strains were isolated from brine (Bohai, Qinhuangdao City, Hebei Province, China). Bioassay results indicated that 4 strains named Ha1, Ha17, Ha38, and Ha384 had herbicidal activity. And strain Ha1 had the highest effective herbicidal activity. As a result, this study aims to identify strain Ha1, characterize its physiological and biological activities, evaluate the herbicidal activity of its metabolites, and develop a‘pesta’ formulation and assess its effectiveness on Digitaria sanguinalis. Ha1 was identiifed as Serratia marcescens based on 16S rDNA sequencing. This strain has a lfagel um, a diameter of 0.5 to 0.8μm, and a length of 0.9 to 2.0μm. The indole test shows positive results, and the catalase enzyme exhibits strong positive reactions. Results further showed that the inhibitory concentration (IC50) of the crude extracts to D. sanguinalis radicula and coleoptile were 3.332 and 2.828 mg mL–1, respectively. Both the suppression of D. sanguinalis and the cel viability of the Ha1 formulation in‘pesta’ were higher when stored at 4°C than at (25±2)°C. These results indi-cated that S. marcescens Ha1 can potential y be used as a biocontrol agent against D. sanguinalis.

  8. Genetic environments of the transferable plasmid-mediated blaCTX-M-3 gene in Serratia marcescens isolates.

    Science.gov (United States)

    Chu, Pei-Yu; Peng, Chien-Fang

    2014-01-01

    In this study, genetic environments of the transferable plasmid-mediated blaCTX-M-3 gene were characterized among 14 isolates of cefotaxime-resistant Serratia marcescens using PCR and BLAST DNA sequence analysis. A total of 3 types of genetic architectures in the regions surrounding this blaCTX-M-3 gene were identified. Type I architecture was characterized by the presence of a complete insertion sequence of tnpA-ISEcp1, identified as interrupting a reverse IS26 sequence in the upstream region of the blaCTX-M-3 gene. A reverse-directional orf477 fragment was located downstream of the blaCTX-M-3 gene, which was in the same direction of the mucA gene. A common region containing the orf513 element was located upstream of the mucA gene. Moreover, a copy of the 3'-CS2 element was located immediately upstream of the orf513 element. A novel complex class 1 integron was characterized by the presence of the dfrA19 gene, which was flanked by two copies of class 1 integrons. This is the first report to describe the dfrA19 gene within a novel complex class 1 integron in S. marcescens isolates from Taiwan. This novel complex class 1 integron structure was located distantly upstream of the blaCTX-M-3 gene.

  9. Ethanol extracts of Serratia marcescens are compatible with Trichoderma isolates for control of damping-off of cucumber caused by Pythium ultimum

    Science.gov (United States)

    Environmentally friendly control measures for soil-borne plant pathogens are needed that are effective in different soils when applied alone or as components of an integrated disease control strategy. Ethanol extracts of Serratia marcescens N4-5 when applied as a cucumber seed treatment effectively ...

  10. Coproduction of KPC-2 and IMP-10 in Carbapenem-Resistant Serratia marcescens Isolates from an Outbreak in a Brazilian Teaching Hospital.

    Science.gov (United States)

    Silva, Kesia Esther; Cayô, Rodrigo; Carvalhaes, Cecilia Godoy; Patussi Correia Sacchi, Flávia; Rodrigues-Costa, Fernanda; Ramos da Silva, Ana Carolina; Croda, Julio; Gales, Ana Cristina; Simionatto, Simone

    2015-07-01

    We describe an outbreak caused by KPC-2- and IMP-10-producing Serratia marcescens isolates in a Brazilian teaching hospital. Tigecycline was the only active antimicrobial agent tested. The blaIMP-10 gene was located in a new class 1 integron, named In990, carried by a nonconjugative plasmid, in contrast to blaKPC-2.

  11. Epidemiology and molecular characterization of extended-spectrum beta-lactamase-producing Enterobacter spp., Pantoea agglomerans, and Serratia marcescens isolates from a Bulgarian hospital.

    Science.gov (United States)

    Markovska, Rumyana Donkova; Stoeva, Temenuga Jekova; Bojkova, Kalina Dineva; Mitov, Ivan Gergov

    2014-04-01

    Forty-two extended-spectrum beta-lactamase (ESBL)-producing isolates of Enterobacter aerogenes, Enterobacter cloacae, Pantoea agglomerans, and Serratia marcescens, collected consecutively during the period January-November 2011 from the University Hospital in Varna, Bulgaria, were studied to characterize their ESBLs by isoelectric focusing, group-specific PCR, and sequencing. The epidemiological relationship was evaluated by random amplified polymorphic DNA analysis (RAPD). Transferability of ESBL genes was determined by conjugation experiments. Plasmid analysis was done by replicon typing and PstI fingerprinting. The overall rate of ESBL production was 20%. The most widespread enzyme was CTX-M-3, found in 64%. It was dominant in E. aerogenes (100%) and S. marcescens (83%). SHV-12, CTX-M-3, and CTX-M-15 were found among E. cloacae isolates in 50%, 35%, and 45%, respectively. Three main CTX-M-3-producing epidemic clones of E. aerogenes and S. marcescens have been detected. Among E. cloacae isolates, six different RAPD profiles were discerned. The plasmids harboring blaCTX-M-3 belonged to IncL/M type and demonstrated similar PstI fingerprinting profiles. IncFII plasmids were detected in two CTX-M-15-producing E. cloacae isolates. Our results demonstrate wide intrahospital dissemination of clonal E. aerogenes and S. marcescens isolates, carrying IncL/M conjugative plasmids.

  12. Coproduction of KPC-2 and IMP-10 in Carbapenem-Resistant Serratia marcescens Isolates from an Outbreak in a Brazilian Teaching Hospital

    Science.gov (United States)

    Silva, Kesia Esther; Cayô, Rodrigo; Carvalhaes, Cecilia Godoy; Patussi Correia Sacchi, Flávia; Rodrigues-Costa, Fernanda; Ramos da Silva, Ana Carolina; Croda, Julio; Gales, Ana Cristina

    2015-01-01

    We describe an outbreak caused by KPC-2- and IMP-10-producing Serratia marcescens isolates in a Brazilian teaching hospital. Tigecycline was the only active antimicrobial agent tested. The blaIMP-10 gene was located in a new class 1 integron, named In990, carried by a nonconjugative plasmid, in contrast to blaKPC-2. PMID:25878341

  13. Fraction Reduction through Continued Fractions

    Science.gov (United States)

    Carley, Holly

    2011-01-01

    This article presents a method of reducing fractions without factoring. The ideas presented may be useful as a project for motivated students in an undergraduate number theory course. The discussion is related to the Euclidean Algorithm and its variations may lead to projects or early examples involving efficiency of an algorithm.

  14. Cloning, expression and characterization of glycerol dehydrogenase involved in 2,3-butanediol formation in Serratia marcescens H30.

    Science.gov (United States)

    Zhang, Liaoyuan; Xu, Quanming; Peng, Xiaoqian; Xu, Boheng; Wu, Yuehao; Yang, Yulong; Sun, Shujing; Hu, Kaihui; Shen, Yaling

    2014-09-01

    The meso-2,3-butanediol dehydrogenase (meso-BDH) from S. marcescens H30 is responsible for converting acetoin into 2,3-butanediol during sugar fermentation. Inactivation of the meso-BDH encoded by budC gene does not completely abolish 2,3-butanediol production, which suggests that another similar enzyme involved in 2,3-butanediol formation exists in S. marcescens H30. In the present study, a glycerol dehydrogenase (GDH) encoded by gldA gene from S. marcescens H30 was expressed in Escherichia coli BL21(DE3), purified and characterized for its properties. In vitro conversion indicated that the purified GDH could catalyze the interconversion of (3S)-acetoin/meso-2,3-butanediol and (3R)-acetoin/(2R,3R)-2,3-butanediol. (2S,3S)-2,3-Butanediol was not a substrate for the GDH at all. Kinetic parameters of the GDH enzyme showed lower K m value and higher catalytic efficiency for (3S/3R)-acetoin in comparison to those for (2R,3R)-2,3-butanediol and meso-2,3-butanediol, implying its physiological role in favor of 2,3-butanediol formation. Maximum activity for reduction of (3S/3R)-acetoin and oxidations of meso-2,3-butanediol and glycerol was observed at pH 8.0, while it was pH 7.0 for diacetyl reduction. The enzyme exhibited relative high thermotolerance with optimum temperature of 60 °C in the oxidation-reduction reactions. Over 60 % of maximum activity was retained at 70 °C. Additionally, the GDH activity was significantly enhanced for meso-2,3-BD oxidation in the presence of Fe(2+) and for (3S/3R)-acetoin reduction in the presence of Mn(2+), while several cations inhibited its activity, particularly Fe(2+) and Fe(3+) for (3S/3R)-acetoin reduction. The properties provided potential application for single configuration production of acetoin and 2,3-butanediol .

  15. Pharmacokinetics of continuous-infusion meropenem for the treatment of Serratia marcescens ventriculitis in a pediatric patient.

    Science.gov (United States)

    Cies, Jeffrey J; Moore, Wayne S; Calaman, Sharon; Brown, Melandee; Narayan, Prithvi; Parker, Jason; Chopra, Arun

    2015-04-01

    Neither guidelines nor best practices for the treatment of external ventricular drain (EVD) and ventriculoperitoneal shunt infections exist. An antimicrobial regimen with a broad spectrum of activity and adequate cerebrospinal fluid (CSF) penetration is vital in the management of both EVD and ventriculoperitoneal infections. In this case report, we describe the pharmacokinetics of continuous-infusion meropenem for a 2-year-old girl with Serratia marcescens ventriculitis. A right frontal EVD was placed for the management of a posterior fossa mass with hydrocephalus and intraventricular hemorrhage. On hospital day 6, CSF specimens were cultured, which identified a pan-sensitive Serratia marcescens with an initial cefotaxime minimum inhibitory concentration of 1 μg/ml or less. The patient was treated with cefotaxime monotherapy from hospital days 6 to 17, during which her CSF cultures and Gram's stain remained positive. On hospital day 26, Serratia marcescens was noted to be resistant to cefotaxime (minimum inhibitory concentration > 16 μg/ml), and the antimicrobial regimen was ultimately changed to meropenem and amikacin. Meropenem was dosed at 40 mg/kg/dose intravenously every 6 hours, infused over 30 minutes, during which, simultaneous serum and CSF meropenem levels were measured. Meropenem serum and CSF levels were measured at 2 and 4 hours from the end of the infusion with the intent to perform a pharmacokinetic/pharmacodynamic analysis. The resulting serum meropenem levels were 12 μg/ml at 2 hours and "undetectable" at 4 hours, with CSF levels of 1 and 0.5 μg/ml at 2 and 4 hours, respectively. On hospital day 27, the meropenem regimen was changed to a continuous infusion of 200 mg/kg/day, with repeat serum and CSF meropenem levels measured on hospital day 33. The serum and CSF levels were noted to be 13 and 0.5 μg/ml, respectively. The serum level of 13 μg/ml corresponds to an estimated meropenem clearance from the serum of 10.2 ml/kg/minute. Repeat

  16. Possibility of using strain F9 (Serratia marcescens) as a bio-collector for hema-tite flotation

    Institute of Scientific and Technical Information of China (English)

    Hui-fen Yang; Tian Li; Yan-hong Chang; Hui Luo; Qiong-yao Tang

    2014-01-01

    In this study, we characterized strain F9 and evaluated the interaction between strain F9 and hematite by scanning electron micros-copy (SEM), Fourier transform infrared spectrophotometry (FTIR), zeta potential, flotation, and other methods. The results showed that strain F9 belongs to Serratia marcescens. This brevibacterium had CH2, CH3, and hydroxyl groups on its cell wall, which imparted a strong hy-drophobic and negative charge. Adsorption of strain F9 reduced the zeta potential of the hematite surface and increased the hydrophobicity of the hematite surface, thereby generating hydrophobic hematite agglomerates. At least four groups on strain F9 interacted with the hematite surface, which contributed to chemical interactions of carboxylic groups and hydrophobic association among hydrophobic hematite particles. The possible use of strain F9 as a bio-collector for hematite flotation was proved.

  17. The Multifarious PGPR Serratia marcescens CDP-13 Augments Induced Systemic Resistance and Enhanced Salinity Tolerance of Wheat (Triticum aestivum L.).

    Science.gov (United States)

    Singh, Rajnish Prakash; Jha, Prabhat Nath

    2016-01-01

    The present study demonstrates the plant growth promoting (PGP) potential of a bacterial isolate CDP-13 isolated from 'Capparis decidua' plant, and its ability to protect plants from the deleterious effect of biotic and abiotic stressors. Based on 16S rRNA gene sequence analysis, the isolate was identified as Serratia marcescens. Among the PGP traits, the isolate was found to be positive for ACC deaminase activity, phosphate solubilization, production of siderophore, indole acetic acid production, nitrogen fixation, and ammonia production. CDP-13 showed growth at an increased salt (NaCl) concentration of up to 6%, indicating its potential to survive and associate with plants growing in saline soil. The inoculation of S. marcescens enhanced the growth of wheat plant under salinity stress (150-200 mM). It significantly reduced inhibition of plant growth (15 to 85%) caused by salt stressors. Application of CDP-13 also modulated concentration (20 to 75%) of different osmoprotectants (proline, malondialdehyde, total soluble sugar, total protein content, and indole acetic acid) in plants suggesting its role in enabling plants to tolerate salt stressors. In addition, bacterial inoculation also reduced the disease severity caused by fungal infection, which illustrated its ability to confer induced systemic resistance (ISR) in host plants. Treatment of wheat plants with the test organism caused alteration in anti-oxidative enzymes activities (Superoxide dismutase, Catalase, and Peroxidase) under various salinity levels, and therefore minimizes the salinity-induced oxidative damages to the plants. Colonization efficiency of strain CDP-13 was confirmed by CFU count, epi-fluorescence microscopy, and ERIC-PCR-based DNA fingerprinting approach. Hence, the study indicates that bacterium CDP-13 enhances plant growth, and has potential for the amelioration of salinity stress in wheat plants. Likewise, the results also provide insights into biotechnological approaches to using PGPR

  18. The Multifarious PGPR Serratia marcescens CDP-13 Augments Induced Systemic Resistance and Enhanced Salinity Tolerance of Wheat (Triticum aestivum L..

    Directory of Open Access Journals (Sweden)

    Rajnish Prakash Singh

    Full Text Available The present study demonstrates the plant growth promoting (PGP potential of a bacterial isolate CDP-13 isolated from 'Capparis decidua' plant, and its ability to protect plants from the deleterious effect of biotic and abiotic stressors. Based on 16S rRNA gene sequence analysis, the isolate was identified as Serratia marcescens. Among the PGP traits, the isolate was found to be positive for ACC deaminase activity, phosphate solubilization, production of siderophore, indole acetic acid production, nitrogen fixation, and ammonia production. CDP-13 showed growth at an increased salt (NaCl concentration of up to 6%, indicating its potential to survive and associate with plants growing in saline soil. The inoculation of S. marcescens enhanced the growth of wheat plant under salinity stress (150-200 mM. It significantly reduced inhibition of plant growth (15 to 85% caused by salt stressors. Application of CDP-13 also modulated concentration (20 to 75% of different osmoprotectants (proline, malondialdehyde, total soluble sugar, total protein content, and indole acetic acid in plants suggesting its role in enabling plants to tolerate salt stressors. In addition, bacterial inoculation also reduced the disease severity caused by fungal infection, which illustrated its ability to confer induced systemic resistance (ISR in host plants. Treatment of wheat plants with the test organism caused alteration in anti-oxidative enzymes activities (Superoxide dismutase, Catalase, and Peroxidase under various salinity levels, and therefore minimizes the salinity-induced oxidative damages to the plants. Colonization efficiency of strain CDP-13 was confirmed by CFU count, epi-fluorescence microscopy, and ERIC-PCR-based DNA fingerprinting approach. Hence, the study indicates that bacterium CDP-13 enhances plant growth, and has potential for the amelioration of salinity stress in wheat plants. Likewise, the results also provide insights into biotechnological approaches to

  19. Engineered Serratia marcescens for efficient (3R)-acetoin and (2R,3R)-2,3-butanediol production.

    Science.gov (United States)

    Bai, Fangmin; Dai, Lu; Fan, Jiying; Truong, Ngoctu; Rao, Ben; Zhang, Liaoyuan; Shen, Yaling

    2015-05-01

    (3R)-Acetoin and (2R,3R)-2,3-butanediol are important pharmaceutical intermediates. However, until now, the quantity of natural microorganisms with the ability to produce single configuration of optically pure (3R)-acetoin and (2R,3R)-2,3-butanediol is rare. In this study, a meso-2,3-butanediol dehydrogenase encoded by the slaC gene from Serratia marcescens MG1 was identified for meso-2,3-butanediol and (2S,3S)-2,3-butanediol biosynthesis. Inactivation of the slaC gene could significantly decrease meso-2,3-butanediol and (2S,3S)-2,3-butanediol and result in a large quantity of (3R)-acetoin accumulation. Furthermore, a (2R,3R)-2,3-butanediol dehydrogenase encoded by the bdhA gene from Bacillus subtilis 168 was introduced into the slaC mutant strain of Serratia marcescens MG1. Excess (2R,3R)-2,3-butanediol dehydrogenase could accelerate the reaction from (3R)-acetoin to (2R,3R)-2,3-butanediol and lead to (2R,3R)-2,3-butanediol accumulation. In fed-batch fermentation, the excess (2R,3R)-2,3-butanediol dehydrogenase expression strain could produce 89.81 g/l (2R,3R)-2,3-butanediol with a productivity of 1.91 g/l/h at 48 h. These results provided potential applications for (3R)-acetoin and (2R,3R)-2,3-butanediol production.

  20. The structure of Serratia marcescens Lip, a membrane-bound component of the type VI secretion system

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Vincenzo A.; Shepherd, Sharon M.; English, Grant; Coulthurst, Sarah J.; Hunter, William N., E-mail: w.n.hunter@dundee.ac.uk [College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland (United Kingdom)

    2011-12-01

    The high-resolution crystal structure of S. marcescens Lip reveals a new member of the transthyretin family of proteins. Lip, a core component of the type VI secretion apparatus, is localized to the outer membrane and is positioned to interact with other proteins forming this complex system. Lip is a membrane-bound lipoprotein and a core component of the type VI secretion system found in Gram-negative bacteria. The structure of a Lip construct (residues 29–176) from Serratia marcescens (SmLip) has been determined at 1.92 Å resolution. Experimental phases were derived using a single-wavelength anomalous dispersion approach on a sample cocrystallized with iodide. The membrane localization of the native protein was confirmed. The structure is that of the globular domain lacking only the lipoprotein signal peptide and the lipidated N-terminus of the mature protein. The protein fold is dominated by an eight-stranded β-sandwich and identifies SmLip as a new member of the transthyretin family of proteins. Transthyretin and the only other member of the family fold, 5-hydroxyisourate hydrolase, form homotetramers important for their function. The asymmetric unit of SmLip is a tetramer with 222 symmetry, but the assembly is distinct from that previously noted for the transthyretin protein family. However, structural comparisons and bacterial two-hybrid data suggest that the SmLip tetramer is not relevant to its role as a core component of the type VI secretion system, but rather reflects a propensity for SmLip to participate in protein–protein interactions. A relatively low level of sequence conservation amongst Lip homologues is noted and is restricted to parts of the structure that might be involved in interactions with physiological partners.

  1. Fractional complex transforms for fractional differential equations

    National Research Council Canada - National Science Library

    Ibrahim, Rabha W

    2012-01-01

    The fractional complex transform is employed to convert fractional differential equations analytically in the sense of the Srivastava-Owa fractional operator and its generalization in the unit disk...

  2. Fractional complex transform for fractional differential equations

    National Research Council Canada - National Science Library

    Lİ, Zheng Biao; HE, Ji Huan

    2010-01-01

    Fractional complex transform is proposed to convert fractional differential equations into ordinary differential equations, so that all analytical methods devoted to advanced calculus can be easily...

  3. Spectroscopic Characterization of Extracellular Polymeric Substances from Escherichia coli and Serratia marcescens: Suppression using Sub-Inhibitory Concentrations of Bismuth Thiols

    Energy Technology Data Exchange (ETDEWEB)

    Badireddy, Appala R.; Korpol, Bhoom Reddy; Chellam, Shankararaman; Gassman, Paul L.; Engelhard, Mark H.; Lea, Alan S.; Rosso, Kevin M.

    2008-10-21

    Free and capsular EPS produced by Escherichia coli and Serratia marcescens were characterized in detail using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES). Total EPS production decreased upon treatment with sub-inhibitory concentrations of lipophilic bismuth thiols (bismuth dimercaptopropanol, BisBAL; bismuth ethanedithiol, BisEDT; and bismuth pyrithione, BisPYR), BisBAL being most effective. Bismuth thiols also influenced acetylation and carboxylation of polysaccharides in EPS from S. marcescens. Extensive homology between EPS samples in the presence and absence of bismuth was observed with proteins, polysaccharides, and nucleic acids varying predominantly only in the total amount expressed. Second derivative analysis of the amide I region of FTIR spectra revealed decreases in protein secondary structures in the presence of bismuth thiols. Hence, anti-fouling properties of bismuth thiols appear to originate in their ability to suppress O-acetylation and protein secondary structures in addition to total EPS secretion.

  4. Evidence for grow-through penetration of 0.2-μm-pore-size filters by Serratia marcescens and Brevundimonas diminuta.

    Science.gov (United States)

    Kaushal, Simran; Gervais, Brandi; Lute, Scott; Eroraha, Ajiri; Faustino, Patrick; Brorson, Kurt; Hussong, David

    2013-04-01

    We find that both Brevundimonas diminuta and Serratia marcescens can grow through sterilizing grade filter membranes of different membrane polymer compositions. Although this passage does not occur on a consistent basis, generation of "grow-through positive" results indicate that grow-through can occur stochastically at basal levels. This observation argues that the following risk mitigation strategies during pharmaceutical aseptic processing are warranted: minimization of processing times, and monitoring, minimizing and characterizing pre-filter bioburden.

  5. Effect of clavulanic acid on activity of beta-lactam antibiotics in Serratia marcescens isolates producing both a TEM beta-lactamase and a chromosomal cephalosporinase.

    Science.gov (United States)

    Bush, K; Flamm, R K; Ohringer, S; Singer, S B; Summerill, R; Bonner, D P

    1991-01-01

    An isolate of Serratia marcescens that produced both an inducible chromosomal and a plasmid-mediated TEM-1 beta-lactamase was resistant to ampicillin and amoxicillin and also demonstrated decreased susceptibility to extended-spectrum beta-lactam antibiotics (ESBAs). Clavulanic acid did not lower the MICs of the ESBAs, but it decreased the MICs of the penicillins. The TEM-1-producing plasmid was transferred to a more susceptible S. marcescens strain that produced a well-characterized inducible chromosomal beta-lactamase. The MICs of the ESBAs remained at a low level for the transconjugant. Ampicillin and amoxicillin which were good substrates for the plasmid-mediated enzyme, were not well hydrolyzed by the chromosomal enzymes; the ESBAs were hydrolyzed slowly by all the enzymes. When each of the S. marcescens strains was grown with these beta-lactam antibiotics, at least modest increases in chromosomal beta-lactamase activity were observed. When organisms were grown in the presence of clavulanic acid and an ESBA, no enhanced induction was observed. The increases in the MICs of the ESBAs observed for the initial clinical isolate may have been due to a combination of low inducibility, slow hydrolysis, and differences in permeability between the S. marcescens isolates. When clavulanic acid and a penicillin were added to strains that produced both a plasmid-mediated TEM and a chromosomal beta-lactamase, much higher levels of chromosomal beta-lactamase activity were present than were observed in cultures induced by the penicillin alone. This was due to the higher levels of penicillin that were available for induction as a result of inhibition of the TEM enzyme by clavulanate. Images PMID:1803992

  6. Distribution, habitat preferences and population sizes of two threatened tree ferns, Cyathea cunninghamii and Cyathea x marcescens, in south-eastern Australia

    OpenAIRE

    Peacock, Ross J.; Downing, Alison; Brownsey, Patrick; Cameron, David

    2013-01-01

    The distribution, population sizes and habitat preferences of the rare tree ferns Cyathea cunninghamii Hook.f. (Slender Tree Fern) and F1 hybrid Cyathea x marcescens N.A.Wakef. (Skirted Tree Fern) in south-eastern Australia are described, together with the extension of the known distribution range of Cyathea cunninghamii from eastern Victoria into south-eastern New South Wales. Floristic and ecological data, encompassing most of the known habitat types, vegetation associations and population ...

  7. Recombinant soluble expression,immobilization and characterization of lipase from Serratia marcescens H30%Serratia marcescens H30脂肪酶的重组可溶表达、固定化及其酶学性质

    Institute of Scientific and Technical Information of China (English)

    徐晶晶; 苏二正; 吴向萍; 马昱澍; 魏东芝

    2014-01-01

    为了提高Serratia marcescens H30脂肪酶的可溶表达水平,分别将目的基因与 pGEX 4T 1、pET28a和pET32a构建重组表达载体,转入大肠杆菌BL21( DE3),通过优化诱导过程,发现可溶性酶的最高活性可达25000 U/L。再经Ni2+亲和柱纯化、LH EP 固定化后,固定化酶的比酶活为214 U/g(以1 g湿质量计),酶活回收率为51%。固定化后重组脂肪酶的最适温度由30℃提高到35℃,最适pH从7�0偏移至8�0左右,并且稳定性也有所增加。该固定化重组脂肪酶同样能够拆分消旋体反式4甲氧苯基缩水甘油酸甲酯,光学选择性没有改变。反应14 h,转化率为48�5%,底物的e�e.值为99�2%,表明该固定化脂肪酶能有效拆分消旋体反式4甲氧苯基缩水甘油酸甲酯,为工业生物催化制备地尔硫卓提供了可能。%To enhance the recombinant soluble expression of lipase from Serratia marcescens H30 in E�coli, different expression vectors such as pGEX⁃4T⁃1, pET28a and pET32a were studied�After optimization of inducing conditions, the maximum lipase activity reached to 25 000 U/L in shake flasks�The recombinant lipase was purified by Ni⁃NTA superflow column�Two carriers were used to immobilize the recombinant lipase, and LH⁃EP was the best one�Optimal temperature and pH of the immobilized lipase were 35 ℃ and 8�0, respectively�The thermal and pH stability of the lipase was improved after being immobilized onto LH⁃EP�The kinetic resolution of ( ± )⁃MPGM by immobilized lipase was studied, and a conversion of 48�5% was achieved along with an e�e. value of 98�2%�Our study reveals the good potential of immobilized Serratia marcescens H30 lipase for application in industrial production of diltiazem.

  8. Effects of temperature, pH and NaCl content on in vitro putrescine and cadaverine production through the growth of Serratia marcescens CCM 303.

    Science.gov (United States)

    Bubelová, Zuzana; Buňka, František; Taťáková, Monika; Štajnochová, Kateřina; Purevdorj, Khatantuul; Buňková, Leona

    2015-01-01

    The aim of this study was to evaluate the combined effect of temperature (10, 20 and 37°C), pH (4, 5, 6, 7 and 8), and NaCl content (0, 1, 3, 4, 5 and 6% w/v) on the growth and putrescine and cadaverine production of Serratia marcescens CCM 303 under model conditions. The decarboxylase activity of S. marcescens was monitored in broth after cultivation. The cultivation medium was enriched with selected amino acids (ornithine, arginine and lysine; 0.2% w/v each) serving as precursors of biogenic amines. Levels of putrescine and cadaverine in broth were analysed by high-performance liquid chromatography after pre-column derivatisation with o-phthalaldehyde reagent. S. marcescens produced higher amounts of putrescine (up to 2096.8 mg L(-1)) compared to cadaverine content (up to 343.3 mg L(-1)) in all cultivation media. The highest putrescine and cadaverine concentrations were reached during cultivation at 10-20°C, pH 5-7 and NaCl content 1-3% w/v. On the other hand, the highest BAs production of individual cell (recalculated based on a cell; so called "yield factor") was observed at 10°C, pH 4 and salt concentration 3-5% w/v as a response to environmental stress.

  9. Culture-dependent and culture-independent analyses reveal no prokaryotic community shifts or recovery of Serratia marcescens in Acropora palmata with white pox disease.

    Science.gov (United States)

    Lesser, Michael P; Jarett, Jessica K

    2014-06-01

    Recently, the etiological agent of white pox (WP) disease, also known as acroporid serratiosis, in the endangered coral Acropora palmata is the enteric bacterium Serratia marcescens with the source being localized sewage release onto coastal coral reef communities. Here, we show that both culture-dependent and culture-independent approaches could not recover this bacterium from samples of tissue and mucus from A. palmata colonies affected by WP disease in the Bahamas, or seawater collected adjacent to A. palmata colonies. Additionally, a metagenetic 16S rRNA pyrosequencing study shows no significant difference in the bacterial communities of coral tissues with and without WP lesions. As recent studies have shown for other coral diseases, S. marcescens cannot be identified in all cases of WP disease in several geographically separated populations of A. palmata with the same set of signs. As a result, its identification as the etiological agent of WP disease, and cause of a reverse zoonosis, cannot be broadly supported. However, the prevalence of WP disease associated with S. marcescens does appear to be associated with proximity to population centers, and research efforts should be broadened to examine this association, and to identify other causes of this syndrome.

  10. The C-type lectin-like domain containing proteins Clec-39 and Clec-49 are crucial for Caenorhabditis elegans immunity against Serratia marcescens infection.

    Science.gov (United States)

    Miltsch, S M; Seeberger, P H; Lepenies, B

    2014-07-01

    Caenorhabditis elegans exhibits protective immunity against a variety of fungal and bacterial pathogens. Since C. elegans lacks an adaptive immune system, pathogen recognition is mediated entirely by innate immunity. To date, little is known about the involvement of pattern recognition receptors (PRRs) in pathogen sensing as part of the C. elegans immunity. C-type lectin-like domain (CTLD) containing proteins represent a superfamily of PRRs. A large number of genes encoding for CTLD proteins are present in the C. elegans genome, however the role of CTLD proteins in bacterial recognition and antibacterial immunity has not yet been determined. In this study, we investigated the function of selected C. elegans CTLD proteins during infection with the Gram-negative bacterium Serratia marcescens. Wild-type and CTLD gene-deficient C. elegans strains were compared in their susceptibility to S. marcescens infection. Interestingly, survival and egg laying were significantly reduced in strains deficient for clec-39 and clec-49 indicating a role for both CTLD proteins in C. elegans immune defense against bacteria as evidenced by using S. marcescens infection. Binding studies with recombinantly expressed Clec-39-Fc and Clec-49-Fc fusion proteins revealed that both CTLD proteins recognized live bacteria in a Ca(2+)-independent manner. This study provides insight into the role of CTLD proteins in C. elegans immunity and demonstrates their function during bacterial infection.

  11. Meadow based Fraction Theory

    OpenAIRE

    Bergstra, Jan A.

    2015-01-01

    In the context of an involutive meadow a precise definition of fractions is formulated and on that basis formal definitions of various classes of fractions are given. The definitions follow the fractions as terms paradigm. That paradigm is compared with two competing paradigms for storytelling on fractions: fractions as values and fractions as pairs.

  12. 柞蚕蛹期灵菌败血病Serratia marcescens C3菌株分离鉴定%Isolation and Identification of Serratia marcescens C3:The Pathogen Causing an Antheraea pernyi Pupal Bacterial Disease

    Institute of Scientific and Technical Information of China (English)

    程瑞春; 崔建国; 王洪魁; 高国平; 孙守慧; 祁金玉; 王月

    2010-01-01

    以柞蚕(Antheraea pernyi)蛹为替代寄主繁殖白蛾周氏啮小蜂(Chouioia cunea)技术在辽宁、北京、天津、上海、河北、山东等地美国白蛾(Hyphantria cunea)的生物防治中发挥了重要作用.利用柞蚕蛹繁殖白蛾周氏啮小蜂时,柞蚕蛹期软化病是繁蜂的主要障碍.通过对利用柞蚕蛹繁蜂时蛹内组织液化后呈粉红色这一未知软化病的典型症状进行病原细菌的分离和纯化,得到C3菌株.经Biolog系统和16S rRNA序列分析,鉴定C3菌株为灵菌(Serratia marcescens),经过柯赫法则检验,确定灵菌C3菌株是导致柞蚕蛹期灵菌败血病的病原菌.描述了繁蜂时柞蚕蛹期灵菌败血病发病期的认别特征.

  13. Research Progress on the Application of Serratia marcescens%黏质沙雷菌应用研究进展

    Institute of Scientific and Technical Information of China (English)

    徐凤宇; 么乃全; 高云航; 胡静涛; 马红霞

    2012-01-01

    普遍存在于自然界的黏质沙雷菌具有广泛用途。无论是基础微生物学研究中应用的模式菌种,还是医药、生物防治领域所用的抗癌、抗细菌、抗真菌等制剂,以及环境修复和化工领域研究中,都有关于黏质沙雷菌的记载。虽然该菌中有些菌株是机会致病菌,但它正在或将来可能带给人类的益处一定是多方面的。%Serratia marcescens is found commonly in the nature with a wide range of applications. It can be used as type culture of the basic microbiology research, preparation for anticancer, antibacterial and antifungal, or in environmental remediation and chemical industry. Although some strains of the bacteria can be the opportunistic pathogen, but it may bring human many benefits in the current and future.

  14. Regulation of the chitin degradation and utilization system by the ChiX small RNA in Serratia marcescens 2170.

    Science.gov (United States)

    Suzuki, Kazushi; Shimizu, Mari; Sasaki, Naomi; Ogawa, Chisana; Minami, Haruka; Sugimoto, Hayuki; Watanabe, Takeshi

    2016-01-01

    Serratia marcescens 2170 produces three different types of chitinases and chitin-binding protein CBP21. We found that transposon insertion into the 5' untranslated region (5' UTR) of chiPQ-ctb led to defective chitinase and CBP21 production. ChiX small RNA possessed the complementary sequence of the 5' UTRs of the chiPQ-ctb and chiR and repressed the expression of chiP and chiR. ChiX was detected in a medium containing glucose, glycerol, GlcNAc, and (GlcNAc)2, but the expression of both chiP and chiR was only observed in a medium containing (GlcNAc)2. ∆chiX mutant produced chitinases, CBP21, and chitobiase without induction. chiP transcripts were more abundant than those of chiR or chiX in a medium containing (GlcNAc)2. These results suggest that the constitutively expressed ChiX binds to the highly abundant chiP 5' UTR, thereby leading to the induction of chiR mRNA translation and the subsequent expression of chitinases and CBP21.

  15. Transcriptomic and proteomic responses of Serratia marcescens to spaceflight conditions involve large-scale changes in metabolic pathways

    Science.gov (United States)

    Wang, Yajuan; Yuan, Yanting; Liu, Jinwen; Su, Longxiang; Chang, De; Guo, Yinghua; Chen, Zhenhong; Fang, Xiangqun; Wang, Junfeng; Li, Tianzhi; Zhou, Lisha; Fang, Chengxiang; Yang, Ruifu; Liu, Changting

    2014-04-01

    The microgravity environment of spaceflight expeditions has been associated with altered microbial responses. This study explores the characterization of Serratia marcescensis grown in a spaceflight environment at the phenotypic, transcriptomic and proteomic levels. From November 1, 2011 to November 17, 2011, a strain of S. marcescensis was sent into space for 398 h on the Shenzhou VIII spacecraft, and ground simulation was performed as a control (LCT-SM213). After the flight, two mutant strains (LCT-SM166 and LCT-SM262) were selected for further analysis. Although no changes in the morphology, post-culture growth kinetics, hemolysis or antibiotic sensitivity were observed, the two mutant strains exhibited significant changes in their metabolic profiles after exposure to spaceflight. Enrichment analysis of the transcriptome showed that the differentially expressed genes of the two spaceflight strains and the ground control strain mainly included those involved in metabolism and degradation. The proteome revealed that changes at the protein level were also associated with metabolic functions, such as glycolysis/gluconeogenesis, pyruvate metabolism, arginine and proline metabolism and the degradation of valine, leucine and isoleucine. In summary S. marcescens showed alterations primarily in genes and proteins that were associated with metabolism under spaceflight conditions, which gave us valuable clues for future research.

  16. Mitochondrial dysfunction in Trypanosoma cruzi: the role of Serratia marcescens prodigiosin in the alternative treatment of Chagas disease

    Directory of Open Access Journals (Sweden)

    Triana Omar

    2011-05-01

    Full Text Available Abstract Background Chagas disease is a health threat for many people, mostly those living in Latin America. One of the most important problems in treatment is the limitation of existing drugs. Prodigiosin, produced by Serratia marcescens (Rhodnius prolixus endosymbiont, belongs to the red-pigmented bacterial prodiginine family, which displays numerous biological activities, including antibacterial, antifungal, antiprotozoal, antimalarial, immunosuppressive, and anticancer properties. Here we describe its effects on Trypanosoma cruzi mitochondria belonging to Tc I and Tc II. Results Parasites exposed to prodigiosin altered the mitochondrial function and oxidative phosphorylation could not have a normal course, probably by inhibition of complex III. Prodigiosin did not produce cytotoxic effects in lymphocytes and Vero cells and has better effects than benznidazole. Our data suggest that the action of prodigiosin on the parasites is mediated by mitochondrial structural and functional disruptions that could lead the parasites to an apoptotic-like cell death process. Conclusions Here, we propose a potentially useful trypanocidal agent derived from knowledge of an important aspect of the natural life cycle of the parasite: the vector-parasite interaction. Our results indicate that prodigiosin could be a good candidate for the treatment of Chagas disease.

  17. Enhancement of prodigiosin production by Serratia marcescens TKU011 and its insecticidal activity relative to food colorants.

    Science.gov (United States)

    Liang, Tzu-Wen; Chen, Shin-Yi; Chen, Yen-Chern; Chen, Chia-Hung; Yen, Yue-Horng; Wang, San-Lang

    2013-11-01

    Prodigiosin (PG) has been reported to have various biological activities. With the aim of increasing Serratia marcescens TKU011 PG production on squid pen powder (SPP)-containing medium, the effects of phosphate and ferrous ion supplementation, autoclave treatment, and aeration were studied. Autoclave treatment showed positive results for PG productivity (2.48 mg/mL), which increased 2.5-fold when the organism was incubated in 50 mL of 40-min autoclaved medium in a baffle-based flask (250 mL) containing 1.5% SPP at 30 °C for 1 day and then at 25 °C for 2 additional days. Furthermore, the use of pigments including PG and the food colorants Allura Red AC (R40) and Tartrazine (Y4) as insecticides was also investigated. The lethal concentrations causing 50% Drosophila larval mortality (LC50) of PG, Y4, and R40 using a 5-d exposure period were 230, 449, and 30000 ppm, respectively. The results indicated that the biopigment PG and the food colorant Y4 were potentially toxic to Drosophila larvae.

  18. STUDY ON SERRATIA MARCESCENS Ⅱ: EFFECTION ON NUTRIENTS AND DIFFERENT COLOR LIGHT TO SERRATIA MARCESCENS GROWTH%粘质沙雷氏菌(Serratia marcescens)研究Ⅱ--营养基质和不同色光对粘质沙雷氏菌生长的影响

    Institute of Scientific and Technical Information of China (English)

    黄文芳; 诸瑜

    2005-01-01

    粘质沙雷氏菌(Serratia marcescens)9-1、9-2、16-1 3菌株,在牛肉膏蛋白胨培养基上生长很好,产生红色菌落. 它们都利用乳糖、D-半乳糖、L-(+)阿拉伯糖、鼠李糖、葡萄糖、蔗糖、D-山梨醇,生长良好并产生红色色素;在硫酸铵、L-赖氨酸、尿素、酪蛋白水解物、DL-天门冬酰胺、胰蛋白胨为氮源的培养基上生长得好并产生红色色素,而在硝酸铵、硝酸钠为氮源的培养基上则生长差和产生粉红色色素;Na+、K+、PO3-4、Ca2+、Mg2+等元素对这3菌株的生长和产生红色色素有一些影响;白色光有促进生长和红色色素的产生,绿色光和黄色光对生长和红色色素产生则有不良影响.

  19. Matrix fractional systems

    Science.gov (United States)

    Tenreiro Machado, J. A.

    2015-08-01

    This paper addresses the matrix representation of dynamical systems in the perspective of fractional calculus. Fractional elements and fractional systems are interpreted under the light of the classical Cole-Cole, Davidson-Cole, and Havriliak-Negami heuristic models. Numerical simulations for an electrical circuit enlighten the results for matrix based models and high fractional orders. The conclusions clarify the distinction between fractional elements and fractional systems.

  20. Study on the protective role of prodigiosine for the pigment-producing bacterium of Serratia marcescens y2%灵菌红素对色素产生菌Serratia marcescens y2作用研究

    Institute of Scientific and Technical Information of China (English)

    刘畅; 王飞; 罗海澜; 周银芳; 李囡囡; 王可; 芦利娟; 王闯

    2011-01-01

    灵菌红素在食品医药等领域具有应用潜力,为研究灵菌红素对产生菌Serratia marcescens y2的作用,以筛选到的产色素菌株(pg+)、色素减少突变株(pg)和不产色素突变株(pg-)为对象,实施不同温度处理后对生长情况、化学杀菌成分抑制效果比较,以了解色素对产生菌的作用。结果表明:在碳氮源适宜的PSA+1%甘氨酸培养基上,较低温度时(17℃),pg+生长量显著少于pg和pg-;温度适宜时pg+生长量显著高于pg和pg-,暗示了色素产生要求能量的消耗,表明适宜环境对菌的生长有促进作用。用牛津杯法实施的化学杀菌成分实验结果表明,色素的存在能保护产生细菌,减少了双氧水、氧氟沙星和氯霉素对细菌的抑制,推测是灵菌红素能抗氧化以缓冲双氧水,以其疏水性吸附阻碍两种抗生素迁移,达到保护产生菌的作用。%Prodigiosine showed potential use in food,medicine and dyeing industry. We focused on the protection function of the pigment on the pigment-producing bacterium. Three mutant strains from Serratia marcescens y2 producing pigment variously was named as pg+(wild type,producing large amount of pigments),pg(less pigment producing)and pg-(non pigment producing). The effects of different temperature and inhibiting effects of several bacterium-killing components on the growth of strains were investigated. In the low-temperature stress(17℃)experiment,the growth of pg+on PSA supplied with 1% glycine was less than that of pg and pg-. While the suitable temperature(25,30℃)results the better growth and more pigment of pg+than pg and pg-. The results indicated that pigment-producing process in pg+cost large amount of energy,so significant less growth was noticed. Under the suitable temperature conditions of 25 ~ 30℃,pg+showed more significant growth than pg and pg-,indicating the growth-promoting effect of prodigiosine for the strains

  1. Identification of Serratia marcescens SE1 and determination of its Herbicide 2,2-dichloropropionate (2,2-DCP Degradation Potential

    Directory of Open Access Journals (Sweden)

    Abel, E.

    2012-01-01

    Full Text Available Aims: The goal of the study is to isolate species of bacteria that capable of utilizing 2,2-dichloropropionic acid (2,2-DCP as sole carbon source from soil sample collected from surrounding lake water located in Universiti Teknologi Malaysia, Skudai, Johor. Methodology and Results: Genomic DNA from bacterium SE1 was extracted and PCR amplification was carried out using universal primers, Fd1 (5’ - AGA GTT TGA TCC TGGCTC AG - 3’ and rP1 (5’- ACG GTC ATA CCT TGT TAC GAC TT - 3’ before sending for sequencing. The 16S rDNA nucleotide sequences were compared with Basic Local Alignment Search Tool nucleotide (BLASTn and further analyzed using phylogenetic tree of Neighbour-Joining method (MEGA 5. Phylogenetic analysis indicated that SE1 strain clearly shared 97% homology to the genus of Serratia marcescens and therefore designated as Serratia marcescens sp. SE1. SE1 exhibited the ability to utilize 2,2-DCP as sole carbon source at 20 mM concentration with cell doubling time of 5 h and maximum chloride ion release of 38 μmolCl-/mL. This result suggests that the dehalogenase enzyme present in the bacteria has high affinity towards the substrate. Based on morphological and partial biochemical characteristics, strain SE1 was a non-motile Gram negative bacterium with red colonies, that gave a catalase positive reaction. Conclusion, significance and impact of study: A better understanding of dehalogenases enzyme produce by this S. marcescens sp. SE1 in general will be useful to be used as bioremediation tools for environmental management. This is the first reported case that Serratia sp. has the ability to degrade halogenated compound.

  2. Serratia marcescens ShlA pore-forming toxin is responsible for early induction of autophagy in host cells and is transcriptionally regulated by RcsB.

    Science.gov (United States)

    Di Venanzio, Gisela; Stepanenko, Tatiana M; García Véscovi, Eleonora

    2014-09-01

    Serratia marcescens is a Gram-negative bacterium that thrives in a wide variety of ambient niches and interacts with an ample range of hosts. As an opportunistic human pathogen, it has increased its clinical incidence in recent years, being responsible for life-threatening nosocomial infections. S. marcescens produces numerous exoproteins with toxic effects, including the ShlA pore-forming toxin, which has been catalogued as its most potent cytotoxin. However, the regulatory mechanisms that govern ShlA expression, as well as its action toward the host, have remained unclear. We have shown that S. marcescens elicits an autophagic response in host nonphagocytic cells. In this work, we determine that the expression of ShlA is responsible for the autophagic response that is promoted prior to bacterial internalization in epithelial cells. We show that a strain unable to express ShlA is no longer able to induce this autophagic mechanism, while heterologous expression of ShlA/ShlB suffices to confer on noninvasive Escherichia coli the capacity to trigger autophagy. We also demonstrate that shlBA harbors a binding motif for the RcsB regulator in its promoter region. RcsB-dependent control of shlBA constitutes a feed-forward regulatory mechanism that allows interplay with flagellar-biogenesis regulation. At the top of the circuit, activated RcsB downregulates expression of flagella by binding to the flhDC promoter region, preventing FliA-activated transcription of shlBA. Simultaneously, RcsB interaction within the shlBA promoter represses ShlA expression. This circuit offers multiple access points to fine-tune ShlA production. These findings also strengthen the case for an RcsB role in orchestrating the expression of Serratia virulence factors.

  3. Outbreak of Serratia marcescens Coproducing ArmA and CTX-M-15 Mediated High Levels of Resistance to Aminoglycoside and Extended-Spectrum Beta-Lactamases, Algeria.

    Science.gov (United States)

    Batah, Rima; Loucif, Lotfi; Olaitan, Abiola Olumuyiwa; Boutefnouchet, Nafissa; Allag, Hamoudi; Rolain, Jean-Marc

    2015-08-01

    Serratia marcescens is one of the most important pathogens responsible for nosocomial infections worldwide. Here, we have investigated the molecular support of antibiotic resistance and genetic relationships in a series of 54 S. marcescens clinical isolates collected from Eastern Algeria between December 2011 and July 2013. The 54 isolates were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). Antibiotic susceptibility testing was performed by disc diffusion and E-test methods. Antibiotic resistance genes were detected by polymerase chain reaction (PCR). The genetic transfer of antibiotic resistance was performed by conjugation using azide-resistant Escherichia coli J53 as the recipient strain, and plasmid analysis was done by PCR-based replicon typing. The relatedness of our isolates was determined by phylogenetic analysis based on partial sequences of four protein-encoding genes (gyrB, rpoB, infB, and atpD) and then compared to MALDI-TOF MS clustering. Thirty-five out of 54 isolates yielded an extended-spectrum β-lactamase (ESBL) phenotype and carried bla(CTX-M-15) (n=32), bla(TEM-1) (n=26), bla(TEM-71) (n=1), bla(SHV-1a) (n=1), and bla(PER-2) (n=12). Among these isolates, we identified a cluster of 15 isolates from a urology unit that coharbored ESBL and the 16S rRNA methyltransferase armA. Conjugation was successful for five selected strains, demonstrating the transferability of a conjugative plasmid of incompatibility group incL/M type. Phylogenetic analysis along with MALDI-TOF clustering likely suggested an outbreak of such isolates in the urology unit. In this study, we report for the first time the co-occurrence of armA methyltransferase with ESBL in S. marcescens clinical isolates in Eastern Algeria.

  4. Study on Serratia marcescensβ-lactam resistance gene%粘质沙雷菌β-内酰胺类耐药基因研究

    Institute of Scientific and Technical Information of China (English)

    谢在海; 朱元祺; 李莉; 邓乃梅; 苏维奇

    2014-01-01

    Objective Survey Serratia marcescens clinical isolatesβ-lactam resistance genes carry case,study its re-sistance mechanisms onβ-lactam antimicrobial.Methods Using Vitek 2 Compact automatic microbial analysis system identification of clinical isolates of Serratia marcescens,287 strains were detected,Susceptibility testing simultaneously selected 135 strains of multi-drug resistant Serratia marcescens.Using double disk confirmatory method for all 287 Ser-ratia marcescens for ESBLs detection,three-dimensional test AmpC enzyme assay,using the PCR method to 135 multi-drug resistant Serratia marcescens forβ-lactam antibiotics related gene SHV,TEM,OXA,PER,VEB,GES,IMP, VIM,FOX,CTX,KPC,DHA,MOX and oprD2 detection.Results Serratia marcescens to ampicillin,ceftriaxone, cefepime,cefotaxime,aztreonam,gentamicin,ciprofloxacin and piperacillin antimicrobial resistance rate is higher,the re-sistance rate of more than 60%,to imipenem,meropenem,sulperazone drug resistance rate is low,the resistance rate of less than 10%.In 287 Serratia marcescens,a total of 32 producing ESBLs,the detection rate of 11.1%,44 strains pro-ducing AmpC,the detection rate of 15.3%,while producing ESBLs and AmpC bacteria 16,accounting for 5.6%.PCR results showed that in 135 multi-drug resistant Serratia marcescens,the CTX-M genes detected with strains 91,TEM gene 25,SHV gene 19,DHA gene 48,KPC gene 10,MOX gene 3,OXA gene 1,oprD2 gene 7.Conclusion The region Serratia marcescens multidrug resistance phenomenon is more serious,the resistance genotype mainly CTX-M and DHA genotype.%目的:调查粘质沙雷菌临床分离株β-内酰胺类耐药基因的携带情况,研究其对β-内酰胺类抗菌药物的耐药机制。方法采用 Vitek2-Compact 全自动微生物系统对临床分离菌进行鉴定,检出粘质沙雷菌287株,同时进行药敏试验,选出多重耐药粘质沙雷菌135株;采用双纸片确证试验对所有287株粘质沙雷菌进行 ESBLs检测、三维试验法检测 Amp

  5. Transfer of drug-resistance plasmids by conjugation from nosocomial strains of Serratia marcescens to Escherichia coli in biological fluids of human origin.

    Science.gov (United States)

    Mendez, F J; Mendoza, M C; Llaneza, J J; Hardisson, C

    1982-09-01

    Six independent isolates of multi-resistant Serratia marcescens associated with nosocomial infections were examined for their ability to transfer drug-resistance plasmids by conjugation to Escherichia coli in biological fluids of human origin, such as normal and pathological urine, faeces, blood plasma and ascitic fluid. Luria broth was used as a control. Positive transfer was found in all media assayed. The different patterns of linked transferable resistance found in the transconjugants corresponded to the phenotypic expression of five plasmids. The frequencies of transfer varied with plasmid types and media employed. The culture media did not affect the phenotypic expression of the plasmids.

  6. Multistate outbreak of Serratia marcescens bloodstream infections caused by contamination of prefilled heparin and isotonic sodium chloride solution syringes.

    Science.gov (United States)

    Blossom, David; Noble-Wang, Judith; Su, John; Pur, Stacy; Chemaly, Roy; Shams, Alicia; Jensen, Bette; Pascoe, Neil; Gullion, Jessica; Casey, Eric; Hayden, Mary; Arduino, Matthew; Budnitz, Daniel S; Raad, Isaam; Trenholme, Gordon; Srinivasan, Arjun

    2009-10-12

    To investigate clusters of Serratia marcescens (SM) bloodstream infections (BSIs) at health care facilities in several states and determine whether contaminated prefilled heparin and isotonic sodium chloride solution (hereinafter, saline) syringes from a single manufacturer (company X) were the likely cause, we performed an outbreak investigation of inpatient and outpatient health care facilities from October 2007 through February 2008. Active case finding for clusters of SM BSIs. Information on SM BSIs was obtained, and SM blood isolates were sent to the Centers for Disease Control and Prevention (CDC). Culture specimens were taken from various lots of prefilled heparin and saline syringes by health care facilities and the CDC to test for the presence of SM. The SM isolates from syringes and blood were compared by pulsed-field gel electrophoresis. A total of 162 SM BSIs in 9 states were reported among patients at facilities using prefilled heparin and/or saline syringes made by company X. Cultures of unopened prefilled heparin and saline syringes manufactured by company X grew SM. Of 83 SM blood isolates submitted to the CDC from 7 states, 70 (84%) were genetically related to the SM strain isolated from prefilled syringes. A US Food and Drug Administration inspection revealed that company X was not in compliance with quality system regulations. A multistate outbreak of SM BSIs was associated with intrinsic contamination of prefilled syringes. Our investigation highlights important issues in medication safety, including (1) the importance of pursuing possible product-associated outbreaks suggested by strong epidemiologic data even when initial cultures of the suspected product show no contamination and (2) the challenges of medical product recalls when production has been outsourced from one company to another.

  7. Structural basis for type VI secreted peptidoglycan DL-endopeptidase function, specificity and neutralization in Serratia marcescens.

    Science.gov (United States)

    Srikannathasan, Velupillai; English, Grant; Bui, Nhat Khai; Trunk, Katharina; O'Rourke, Patrick E F; Rao, Vincenzo A; Vollmer, Waldemar; Coulthurst, Sarah J; Hunter, William N

    2013-12-01

    Some Gram-negative bacteria target their competitors by exploiting the type VI secretion system to extrude toxic effector proteins. To prevent self-harm, these bacteria also produce highly specific immunity proteins that neutralize these antagonistic effectors. Here, the peptidoglycan endopeptidase specificity of two type VI secretion-system-associated effectors from Serratia marcescens is characterized. These small secreted proteins, Ssp1 and Ssp2, cleave between γ-D-glutamic acid and L-meso-diaminopimelic acid with different specificities. Ssp2 degrades the acceptor part of cross-linked tetratetrapeptides. Ssp1 displays greater promiscuity and cleaves monomeric tripeptides, tetrapeptides and pentapeptides and dimeric tetratetra and tetrapenta muropeptides on both the acceptor and donor strands. Functional assays confirm the identity of a catalytic cysteine in these endopeptidases and crystal structures provide information on the structure-activity relationships of Ssp1 and, by comparison, of related effectors. Functional assays also reveal that neutralization of these effectors by their cognate immunity proteins, which are called resistance-associated proteins (Raps), contributes an essential role to cell fitness. The structures of two immunity proteins, Rap1a and Rap2a, responsible for the neutralization of Ssp1 and Ssp2-like endopeptidases, respectively, revealed two distinct folds, with that of Rap1a not having previously been observed. The structure of the Ssp1-Rap1a complex revealed a tightly bound heteromeric assembly with two effector molecules flanking a Rap1a dimer. A highly effective steric block of the Ssp1 active site forms the basis of effector neutralization. Comparisons with Ssp2-Rap2a orthologues suggest that the specificity of these immunity proteins for neutralizing effectors is fold-dependent and that in cases where the fold is conserved sequence differences contribute to the specificity of effector-immunity protein interactions.

  8. Initialized Fractional Calculus

    Science.gov (United States)

    Lorenzo, Carl F.; Hartley, Tom T.

    2000-01-01

    This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.

  9. Fraction Sense: Foundational Understandings.

    Science.gov (United States)

    Fennell, Francis Skip; Karp, Karen

    2016-08-09

    The intent of this commentary is to identify elements of fraction sense and note how the research studies provided in this special issue, in related but somewhat different ways, validate the importance of such understandings. Proficiency with fractions serves as a prerequisite for student success in higher level mathematics, as well as serving as a gateway to many occupations and varied contexts beyond the mathematics classroom. Fraction sense is developed through instructional opportunities involving fraction equivalence and magnitude, comparing and ordering fractions, using fraction benchmarks, and computational estimation. Such foundations are then extended to operations involving fractions and decimals and applications involving proportional reasoning. These components of fraction sense are all addressed in the studies provided in this issue, with particular consideration devoted to the significant importance of the use of the number line as a central representational tool for conceptually understanding fraction magnitude.

  10. Purification, crystallization and preliminary X-ray analysis of the outer membrane complex HasA–HasR from Serratia marcescens

    Energy Technology Data Exchange (ETDEWEB)

    Huché, Frédéric, E-mail: huche@pasteur.fr [Fachbereich Biologie, Universität Konstanz, 78457 Konstanz (Germany); Unité des Membranes Bactériennes, CNRS URA 2172, Département de Microbiologie Fondamentale et Médicale, Institut Pasteur, 25-28 Rue du Dr Roux, 75724 Paris CEDEX 15 (France); Delepelaire, Philippe; Wandersman, Cécile [Unité des Membranes Bactériennes, CNRS URA 2172, Département de Microbiologie Fondamentale et Médicale, Institut Pasteur, 25-28 Rue du Dr Roux, 75724 Paris CEDEX 15 (France); Welte, Wolfram [Fachbereich Biologie, Universität Konstanz, 78457 Konstanz (Germany)

    2006-01-01

    The expression, purification, and crystallization in space group P2{sub 1}2{sub 1}2{sub 1} of the complex HasA-HasR from S. marcescens are reported. Diffraction data have been collected and processed to 6.8 Å. Serratia marcescens is able to acquire iron using its haem-acquisition system (‘has’), which contains an outer membrane receptor HasR and a soluble haemophore HasA. After secretion, HasA binds free haem in the extracellular medium or extracts it from haemoproteins and delivers it to the receptor. Here, the crystallization of a HasA–HasR complex is reported. HasA and HasR have been overexpressed in Escherichia coli and the complex formed and crystallized. Small platelets and bunches of needles of dimensions 0.01 × 0.1 × 1 mm were obtained. A native data set has been collected to 6.8 Å.

  11. Study on the drug resistance and genotyping of Serratia marcescens%褪色沙雷菌耐药性及基因分型研究

    Institute of Scientific and Technical Information of China (English)

    苏维奇; 邓乃梅; 李莉; 朱元祺; 毕春霞; 闫志勇

    2015-01-01

    OBJECTIVE To understand the current situation of hospital infection of regional clinical isolates of Serratia marcescens , to establish random amplified polymorphic DNA (RAPD ) genotyping methods for genotyping of S .marcescens clinical isolates to provide molecular epidemiological data for the control of nosocomial infections .METHODS Infectious clinical specimens were collected between Jan .2010 - Dec .2012 ,and were isolated and cultured using conventional methods .VITEK‐2 Compact automatic microbial analysis system was used for strain identification and MIC determination was conducted to commonly used antimicrobial drugs .WHO‐NET5 .6 software was used to statistically analyze the specimen sources ,clinical distribution and drug resistance spectrum of the 287 clinical isolates of S .marcescens .Genotyping was performed by RAPD technique .RESULTS The 287 strains of S .marcescens were mainly from ICU ,respiratory and neurology ward ,accounting for 37 .6% , 31 .7% and 14 .6% ,respectively .The sources of specimens included respiratory tract 77 .7% ,urinary tract 11 .1% and operative site 8 .0% .Drug sensitivity results showed ,the drug resistance rates of S .marcescens to meropenem and imipenem , sulperazon were below 10 .0% , while the rates to ampicillin , piperacillin and ceftriaxone were greater than 70 .0% .Using RAPD technique ,the 287 strains of S .marcescens were divided into 12 genotypes ,A -L type ,in which A and D were the dominant types .CONCLUSION S .marcescens was mainly from the respiratory specimens of ICU ,respiratory and neurology ward ,and the multidrug resistance phenomenon was quite serious . S .marcescens in the region could be divided into 12 genotypes ,with A and D as the most common types .%目的:了解褪色沙雷菌临床分离株的医院感染现状,建立随机扩增多态性DNA(RAPD)基因分型方法,对褪色沙雷菌临床分离株进行基因分型,为控制医院感染提供分子流

  12. 粘质沙雷氏菌代谢产物灵菌红素的鉴定%Identification of Metabolite Prodigiosin of Serratia Marcescens

    Institute of Scientific and Technical Information of China (English)

    朱雄伟; 徐智鹏; 张楠; 苏腾甲; 陈杏洲; 邢彦君; 李卫朋

    2012-01-01

    A red pigment-producing strain Serratia marcescens ZSG was isolated from the acidic soil of a citric acid plant saccharification workshop. By acidic methanol extraction,concentration,silica gel column chroma-tography,thin-layer chromatography and column chromatography,the pure prodigiosin was separated and purified from the fermentation broth,and its structure was characterized by UV-Vis,IR and LC-MS.%从柠檬酸厂糖化车间酸性土壤中筛选得到一株产红色素的粘质沙雷氏菌(Serratia marcescens)ZSG,菌株发酵液经酸性甲醇萃取、浓缩、硅胶柱层析、薄层色谱和柱色谱等分离纯化后,得到灵菌红素纯品,并采用紫外可见吸收光谱、红外光谱、液质联用分析对其结构进行了表征.

  13. Biotransformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by a prospective consortium and its most effective isolate Serratia marcescens

    Energy Technology Data Exchange (ETDEWEB)

    Young, D.M.; Ogden, K.L. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Chemical and Environmental Engineering; Unkefer, P.J. [Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.

    1997-03-05

    The biotransformation of hexahydro-1,3,5-trinitro-1,3,5 triazine (RDX) has been observed in liquid culture by a consortium of bacteria found in horse manure. Five types of bacteria were found to predominate in the consortium and were isolated. The most effective of these isolates at transforming RDX was Serratia marcescens. The biotransformation of RDX by all of these bacteria was found to occur only in the anoxic stationary phase. The process of bacterial growth and RDX biotransformation was quantified for the purpose of developing a predictive type model. Cell growth was assumed to follow Monod kinetics. All of the aerobic and anoxid growth parameters were determined: {mu}{sub max}, K{sub s}, and Y{sub x/s}. RDX was found to competitively inhibit cell growth in both atmospheres. Degradation of RDX by Serratia marcescens was found to proceed through the stepwise reduction of the three nitro groups to nitroso groups. Each of these reductions was found to be first order in both component and cell concentrations. The degradation rate constant for the first step in this reduction process by the consortium was 0.022 L/g cells {center_dot} h compared to 0.033 L/g cells {center_dot} h for the most efficient isolate.

  14. Study on Optimization of Fermentative Culture Media of Serratia marcescens%粘质沙雷氏菌(Serratia marcescens)发酵培养基优化的研究

    Institute of Scientific and Technical Information of China (English)

    郝林华; 陈靠山; 牛德庆; 张玉凤

    2006-01-01

    采用单因素试验和正交试验,对从山东东营海岸湿地盐碱滩地土壤中筛选出的一株海洋菌种--粘质沙雷氏菌(Serratia marcescens)的发酵培养基进行优化,并进行100 L发酵罐中试放大试验的研究.确定粘质沙雷氏菌的最佳培养基配方为葡萄糖 10 g/L,硫酸铵 5 g/L,麸皮 50 g/L,柠檬酸三钠 1.0 g/L,K2HPO4·3H2O 0.3 g/L,FeSO4·7H2O 0.05 g/L,MgSO4·7H2O 0.5 g/L,pH 7.2~7.7.发酵最适温度为30 ℃.通过测定粘质沙雷氏菌在发酵罐中培养的生长曲线,确定发酵时间以28~30 h为宜,发酵结束后发酵液中的活菌数约为50×108 个/mL.将所筛选到的粘质沙雷氏菌应用于农作物的病害防治,效果非常显著,表明是一株高活性的生物防治拮抗菌.此研究结果为高效率、低成本和工业化生产具有生物防治作用的海洋菌种制剂提供了科学依据,也为海岸湿地盐碱土的可持续开发利用提供了技术支撑.

  15. Meaning of Fractions

    Science.gov (United States)

    Dewi, D. A. K.; Suryadi, D.; Suratno, T.; Mulyana, E.; Kurniawan, H.

    2017-02-01

    Introducing fractions is identical to divide an object. Suppose we divide the apple into two parts. One divided into two parts, the question arises whether one part can be called a half or not. Based on this activity, how can students give meaning to fractions. This study aims at designing a different fractions lesson by applying Didactical Design Research. In doing so, we undertook several research phases: 1) thinking what is fractions and why students should learn this concept; 2) designing didactical situation based on identified learning obstacles; and 3) reflecting retrospectively on the lesson design and its implementation as to redesign the fractions lesson. Our analysis revealed that most students held epistemological obstacles in giving meaning of fractions because they only know fractions as numbers that have numerator and denominator. By positioning ourselves as students, we discuss the ideal design to help students in constructing the meaning of fractions.

  16. Fractional Dynamical Systems

    CERN Document Server

    Edelman, Mark

    2014-01-01

    In this paper the author presents the results of the preliminary investigation of fractional dynamical systems based on the results of numerical simulations of fractional maps. Fractional maps are equivalent to fractional differential equations describing systems experiencing periodic kicks. Their properties depend on the value of two parameters: the non-linearity parameter, which arises from the corresponding regular dynamical systems; and the memory parameter which is the order of the fractional derivative in the corresponding non-linear fractional differential equations. The examples of the fractional Standard and Logistic maps demonstrate that phase space of non-linear fractional dynamical systems may contain periodic sinks, attracting slow diverging trajectories, attracting accelerator mode trajectories, chaotic attractors, and cascade of bifurcations type trajectories whose properties are different from properties of attractors in regular dynamical systems. The author argues that discovered properties s...

  17. Structural basis for type VI secreted peptidoglycan dl-endopeptidase function, specificity and neutralization in Serratia marcescens

    Energy Technology Data Exchange (ETDEWEB)

    Srikannathasan, Velupillai; English, Grant [University of Dundee, Dundee DD1 5EH, Scotland (United Kingdom); Bui, Nhat Khai [Newcastle University, Newcastle upon Tyne NE2 4HH (United Kingdom); Trunk, Katharina; O’Rourke, Patrick E. F.; Rao, Vincenzo A. [University of Dundee, Dundee DD1 5EH, Scotland (United Kingdom); Vollmer, Waldemar [Newcastle University, Newcastle upon Tyne NE2 4HH (United Kingdom); Coulthurst, Sarah J., E-mail: s.j.coulthurst@dundee.ac.uk; Hunter, William N., E-mail: s.j.coulthurst@dundee.ac.uk [University of Dundee, Dundee DD1 5EH, Scotland (United Kingdom)

    2013-12-01

    Crystal structures of type VI secretion system-associated immunity proteins, a peptidoglycan endopeptidase and a complex of the endopeptidase and its cognate immunity protein are reported together with assays of endopeptidase activity and functional assessment. Some Gram-negative bacteria target their competitors by exploiting the type VI secretion system to extrude toxic effector proteins. To prevent self-harm, these bacteria also produce highly specific immunity proteins that neutralize these antagonistic effectors. Here, the peptidoglycan endopeptidase specificity of two type VI secretion-system-associated effectors from Serratia marcescens is characterized. These small secreted proteins, Ssp1 and Ssp2, cleave between γ-d-glutamic acid and l-meso-diaminopimelic acid with different specificities. Ssp2 degrades the acceptor part of cross-linked tetratetrapeptides. Ssp1 displays greater promiscuity and cleaves monomeric tripeptides, tetrapeptides and pentapeptides and dimeric tetratetra and tetrapenta muropeptides on both the acceptor and donor strands. Functional assays confirm the identity of a catalytic cysteine in these endopeptidases and crystal structures provide information on the structure–activity relationships of Ssp1 and, by comparison, of related effectors. Functional assays also reveal that neutralization of these effectors by their cognate immunity proteins, which are called resistance-associated proteins (Raps), contributes an essential role to cell fitness. The structures of two immunity proteins, Rap1a and Rap2a, responsible for the neutralization of Ssp1 and Ssp2-like endopeptidases, respectively, revealed two distinct folds, with that of Rap1a not having previously been observed. The structure of the Ssp1–Rap1a complex revealed a tightly bound heteromeric assembly with two effector molecules flanking a Rap1a dimer. A highly effective steric block of the Ssp1 active site forms the basis of effector neutralization. Comparisons with Ssp2–Rap2

  18. On continued fraction algorithms

    NARCIS (Netherlands)

    Smeets, Ionica

    2010-01-01

    Is there a good continued fraction approximation between every two bad ones? What is the entropy of the natural extension for alpha-Rosen fractions? How do you find multi-dimensional continued fractions with a guaranteed quality in polynomial time? These, and many more, questions are answered in thi

  19. DIY Fraction Pack.

    Science.gov (United States)

    Graham, Alan; Graham, Louise

    2003-01-01

    Describes a very successful attempt to teach fractions to year 5 pupils based on pupils making their own fraction pack. Children decided for themselves how to make the fractional slices used in the activity using colored cardboard sheets and templates of a paper circle consisting of 24 equal slices. (Author/NB)

  20. On continued fraction algorithms

    NARCIS (Netherlands)

    Smeets, Ionica

    2010-01-01

    Is there a good continued fraction approximation between every two bad ones? What is the entropy of the natural extension for alpha-Rosen fractions? How do you find multi-dimensional continued fractions with a guaranteed quality in polynomial time? These, and many more, questions are answered in thi

  1. Fractional Differential Equations

    Directory of Open Access Journals (Sweden)

    Jianping Zhao

    2012-01-01

    Full Text Available An extended fractional subequation method is proposed for solving fractional differential equations by introducing a new general ansätz and Bäcklund transformation of the fractional Riccati equation with known solutions. Being concise and straightforward, this method is applied to the space-time fractional coupled Burgers’ equations and coupled MKdV equations. As a result, many exact solutions are obtained. It is shown that the considered method provides a very effective, convenient, and powerful mathematical tool for solving fractional differential equations.

  2. Fractional smith chart theory

    KAUST Repository

    Shamim, Atif

    2011-03-01

    For the first time, a generalized Smith chart is introduced here to represent fractional order circuit elements. It is shown that the standard Smith chart is a special case of the generalized fractional order Smith chart. With illustrations drawn for both the conventional integer based lumped elements and the fractional elements, a graphical technique supported by the analytical method is presented to plot impedances on the fractional Smith chart. The concept is then applied towards impedance matching networks, where the fractional approach proves to be much more versatile and results in a single element matching network for a complex load as compared to the two elements in the conventional approach. © 2010 IEEE.

  3. Fractional Dynamics and Control

    CERN Document Server

    Machado, José; Luo, Albert

    2012-01-01

    Fractional Dynamics and Control provides a comprehensive overview of recent advances in the areas of nonlinear dynamics, vibration and control with analytical, numerical, and experimental results. This book provides an overview of recent discoveries in fractional control, delves into fractional variational principles and differential equations, and applies advanced techniques in fractional calculus to solving complicated mathematical and physical problems.Finally, this book also discusses the role that fractional order modeling can play in complex systems for engineering and science. Discusses how fractional dynamics and control can be used to solve nonlinear science and complexity issues Shows how fractional differential equations and models can be used to solve turbulence and wave equations in mechanics and gravity theories and Schrodinger’s equation  Presents factional relaxation modeling of dielectric materials and wave equations for dielectrics  Develops new methods for control and synchronization of...

  4. Fractional factorial plans

    CERN Document Server

    Dey, Aloke

    2009-01-01

    A one-stop reference to fractional factorials and related orthogonal arrays.Presenting one of the most dynamic areas of statistical research, this book offers a systematic, rigorous, and up-to-date treatment of fractional factorial designs and related combinatorial mathematics. Leading statisticians Aloke Dey and Rahul Mukerjee consolidate vast amounts of material from the professional literature--expertly weaving fractional replication, orthogonal arrays, and optimality aspects. They develop the basic theory of fractional factorials using the calculus of factorial arrangements, thereby providing a unified approach to the study of fractional factorial plans. An indispensable guide for statisticians in research and industry as well as for graduate students, Fractional Factorial Plans features: * Construction procedures of symmetric and asymmetric orthogonal arrays. * Many up-to-date research results on nonexistence. * A chapter on optimal fractional factorials not based on orthogonal arrays. * Trend-free plans...

  5. Dividing Fractions: A Pedagogical Technique

    Science.gov (United States)

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  6. 褪色沙雷菌的医院感染分布与耐药性分析%Distribution and drug resistance of Serratia marcescens causing nosocomial infections

    Institute of Scientific and Technical Information of China (English)

    卫叶林; 来汉江; 佘军; 朱彤

    2012-01-01

    OBJECTIVE To explore the clinical distribution and drug resistance of Serratia marcescens causing nosocomial infections in the ICU and non-ICU so as to provide bases for reasonable use of antibiotics. METHODS The in vitro drug susceptibility testing was performed for 156 clinical isolates of S. marcescens by using KB method, β-lactamase was detected at the same time. RESULTS Of 156 strains of S. marcescens cultured and isolated, there were 57 (36. 5%) strains in ICU, 52 (33. 3%) strains in respiratory department, 28 (17. 9%) strains in neurology department, and 19 (12. 2%) strains in other departments; the average drug resistance rates to imipenem and cefoperazone/sulbactam were 5. 1% and 1.9%, the drug resistance rates to ampicillin, cefazolin, and amoxicillin/clavulanic acid were higher than 90. 0%; there were 21 strains of Ampc enzyme-producing S. marcescens detected with the detection rate of 13. 5%, 18 strains of ESBLs-producing S. marcescens with detection rate of 11. 5% and 7 strains of both Ampc enzyme and ESBLs-producing S. marcescens with detection rate of 4. 5%. CONCLUSION The drug resistance rate of S. marcescens strains isolated from ICU is significantly higher than those isolated from non-ICUs; the detection rates of the three phenotypes of Ampc and ESBLs are higher in ICU than in non-ICUs; the drug resistant mechanism of S. marcescens is complex,and S. marcescens is resistant to multiple antibiotics, it is necessary to reasonably choose antibiotics on the basis of drug susceptibility testing.%目的 了解褪色沙雷菌在医院感染的临床分布和在ICU与非ICU的耐药性,为临床合理选择和应用抗菌药物提供依据.方法 用K-B法对临床分离出的156株褪色沙雷菌进行体外药物敏感试验并统计分析,同时检测其β-内酰胺酶.结果 分离培养的156株褪色沙雷菌在科室分布,ICU 57株占36.5%、呼吸科52株占33.3%、神经内科28株占17.9%、其他科室19株占12.2%;对亚胺培南

  7. Nosocomial outbreak of Serratia marcescens in a Neonatal Intensive Care Unit: what to do not to close the unit when cohorting is not enough

    Directory of Open Access Journals (Sweden)

    Lorenza Pugni

    2014-12-01

    Full Text Available Background. Serratia marcescens, a Gram-negative organism, is a well-recognized nosocomial pathogen, especially in Neonatal Intensive Care Units (NICUs. Even if multiple point sources have been identified, the source of an outbreak often remains unknown. Because an outbreak of S. marcescens can spread rapidly, closing the Unit sometimes is necessary. Here, we report on an outbreak of S. marcescens occurred in our NICU and describe the control measures taken to stop the epidemic without closing the Unit. Material and Methods. Our Unit is a 56-bed Unit composed of two areas: a 23-bed (4 rooms intensive-care and a 33-bed (6 rooms intermediate-care area. After some cases of S. marcescens infection were identified during a 3-month period, a prospective epidemiological study was performed in both areas during a period of 8 months. Surveillance cultures were obtained from all neonates (pharynx, rectum, eyes, ears at admission, at room-changing and twice weekly, from medical and nursing staff (pharynx, rectum and from the environment (sinks, ventilators, incubators, soap dispensers, disinfectants, breast pumps, work surfaces. The following control measures were also taken: universal precautions were intensified (handwashing, gloves, masks, education of the staff was stressed, a survey was instituted to check the observance of the control measures, admissions to the NICU were limited and infected/colonized babies were strictly cohorted. Because the outbreak continued despite these control measures, we separated new admissions from hospitalized babies by using two ways in the Unit: a clean way (green and a dirty way (red with nurses, rooms and everything different between the green and the red babies. Results. During the study period, 589 neonates underwent surveillance cultures (14.156 samples; 32/589 (5% infants had positive swabs. Four (12.5% of the 32 colonized infants had clinical signs of infection: sepsis-like symptoms (2 cases and conjunctivitis

  8. Characterization of nosocomial Serratia marcescens isolates: comparison of Fourier-transform infrared spectroscopy with pulsed-field gel electrophoresis of genomic DNA fragments and multilocus enzyme electrophoresis.

    Science.gov (United States)

    Irmscher, H M; Fischer, R; Beer, W; Seltmann, G

    1999-07-01

    A total of 66 Serratia marcescens isolates from 46 patients was investigated by macrorestriction using XbaI followed by pulsed-field gel electrophoresis. 7 restriction fragment patterns attributable to more than one patient and 9 individual patterns were identified. The isolates were additionally characterized by multilocus enzyme electrophoresis and Fourier-transform infrared spectroscopy. The macrorestriction patterns and the multilocus enzyme electrophoresis patterns corresponded fairly well while the classifications derived from these methods were not completely congruent. The grouping achieved by Fourier-transform infrared spectroscopy on the basis of high (> 1000) and moderately high heterogeneity values (300) was consistent with the macrorestriction results. Grouping on a lower heterogeneity level did not contribute to further discrimination. In general, Fourier-transform infrared spectroscopy was less discriminatory than the two other methods, but easier to perform. Therefore, laboratories equipped with the necessary devices may use it to rapidly select bacterial isolates for macrorestriction or other well established characterization procedures.

  9. Fractional Pure Birth Processes

    CERN Document Server

    Orsingher, Enzo; 10.3150/09-BEJ235

    2010-01-01

    We consider a fractional version of the classical non-linear birth process of which the Yule-Furry model is a particular case. Fractionality is obtained by replacing the first-order time derivative in the difference-differential equations which govern the probability law of the process, with the Dzherbashyan-Caputo fractional derivative. We derive the probability distribution of the number $ \\mathcal{N}_\

  10. Fractional vortex Hilbert's Hotel

    CERN Document Server

    Gbur, Greg

    2015-01-01

    We demonstrate how the unusual mathematics of transfinite numbers, in particular a nearly perfect realization of Hilbert's famous hotel paradox, manifests in the propagation of light through fractional vortex plates. It is shown how a fractional vortex plate can be used, in principle, to create any number of "open rooms," i.e. topological charges, simultaneously. Fractional vortex plates are therefore demonstrated to create a singularity of topological charge, in which the vortex state is completely undefined and in fact arbitrary.

  11. Fractional Electromagnetic Waves

    CERN Document Server

    Gómez, J F; Bernal, J J; Tkach, V I; Guía, M

    2011-01-01

    In the present work we consider the electromagnetic wave equation in terms of the fractional derivative of the Caputo type. The order of the derivative being considered is 0 <\\gamma<1. A new parameter \\sigma, is introduced which characterizes the existence of the fractional components in the system. We analyze the fractional derivative with respect to time and space, for \\gamma = 1 and \\gamma = 1/2 cases.

  12. The mechanism of carbapenems resistance in Serratia marcescens strains%粘质沙雷菌碳青霉烯类耐药机制研究

    Institute of Scientific and Technical Information of China (English)

    孙瑶; 张环; 刘俊; 张晓蕾; 张亚培; 李梅梅; 周铁丽

    2014-01-01

    目的:了解临床分离的粘质沙雷菌碳青霉烯类药物耐药机制及流行特点。方法收集温州医科大学附属第一医院2006-2012年临床分离的147株粘质沙雷菌,用Vitek2 Compact及配套革兰阴性细菌药敏卡检测其药敏情况;筛选出的11株碳青霉烯类耐药的粘质沙雷菌,用琼脂稀释法测定其对10种常见抗菌药物的MIC值;改良Hodge试验进行碳青霉烯酶表型检测;PCR检测碳青霉烯酶、AmpC酶、外排泵及外膜蛋白基因的携带情况;琼脂稀释法测定加入外排泵抑制剂CCCP前后碳青霉烯类药物MIC值的变化;SDS-PAGE分析菌株外膜蛋白有无缺失;对碳青霉烯耐药菌株进行接合转移试验,PCR扩增并测定接合子的MIC,PFGE分析菌株之间的同源性。结果11株粘质沙雷菌对青霉素类、头孢菌素类抗生素和厄他培南全部耐药,其中10株菌同时对亚胺培南和美罗培南耐药,但对氟喹诺酮类和氨基糖苷类药物有较好的敏感性;11株菌中10株携带blaKPC-2,1株携带blaIMP-1,8株菌同时携带blaEBC和blaMOX ,1株同时携带blaEBC和blaDHA ,1株菌同时携带blaEBC、blaMOX和blaDHA基因,其他基因未检出;加入CCCP后有7株菌对亚胺培南的MIC值降低4~64倍,有3株菌对厄他培南的MIC值降低8~256倍,而对美罗培南的MIC值没有变化;11株菌均未检出外膜蛋白缺失;有7株菌的blaKPC-2基因成功转移到受体菌,接合子与受体菌相比MIC值有不同程度提高;PFGE结果显示11株菌中有8株菌属于一个克隆型。结论产KPC-2碳青霉烯酶是本院粘质沙雷菌对碳青霉烯类耐药的主要原因,本研究表明KPC-2在温州地区存在克隆播散并且可以水平传播,故应引起高度重视。%Objective To investigate the mechanism of carbapenems resistance in Serratia marces-cens strains isolated from Wenzhou and their epidemiological characteristics.Methods 147 non

  13. Fractional and noncommutative spacetimes

    NARCIS (Netherlands)

    Arzano, M.; Calcagni, M.; Oriti, D.; Scalisi, M.

    2011-01-01

    We establish a mapping between fractional and noncommutative spacetimes in configuration space. Depending on the scale at which the relation is considered, there arise two possibilities. For a fractional spacetime with log-oscillatory measure, the effective measure near the fundamental scale determi

  14. Can Kindergartners Do Fractions?

    Science.gov (United States)

    Cwikla, Julie

    2014-01-01

    Mathematics professor Julie Cwikla decided that she needed to investigate young children's understandings and see what precurricular partitioning notions young minds bring to the fraction table. Cwikla realized that only a handful of studies have examined how preschool-age and early elementary school-age students solve fraction problems (Empson…

  15. Can Kindergartners Do Fractions?

    Science.gov (United States)

    Cwikla, Julie

    2014-01-01

    Mathematics professor Julie Cwikla decided that she needed to investigate young children's understandings and see what precurricular partitioning notions young minds bring to the fraction table. Cwikla realized that only a handful of studies have examined how preschool-age and early elementary school-age students solve fraction problems (Empson…

  16. An Appetite for Fractions

    Science.gov (United States)

    Wilkerson, Trena L.; Bryan, Tommy; Curry, Jane

    2012-01-01

    This article describes how using candy bars as models gives sixth-grade students a taste for learning to represent fractions whose denominators are factors of twelve. Using paper models of the candy bars, students explored and compared fractions. They noticed fewer different representations for one-third than for one-half. The authors conclude…

  17. Categories of Fractions Revisited

    OpenAIRE

    Fritz, Tobias

    2008-01-01

    The theory of categories of fractions as originally developed by Gabriel and Zisman is reviewed in a pedagogical manner giving detailed proofs of all statements. A weakening of the category of fractions axioms used by Higson is discussed and shown to be equivalent to the original axioms.

  18. On fractional programming

    Energy Technology Data Exchange (ETDEWEB)

    Bajona-Xandri, C.; Martinez-Legaz, J.E.

    1994-12-31

    This paper studies the minimax fractional programming problem, assuming quasiconvexity of the objective function, under the lower subdifferentiability viewpoint. Necessary and sufficient optimality conditions and dual properties are found. We present applications of this theory to find the Pareto efficient solutions of a multiobjective fractional problem and to solve several economic models.

  19. 褪色沙雷菌3-内酰胺酶检测及耐药机制研究%Detection of β-lactamases produced by Serratia marcescens and study on drug-resistant mechanism

    Institute of Scientific and Technical Information of China (English)

    苏维奇; 谢在海; 朱元祺

    2012-01-01

    OBJECTIVE To investigate the β-lactamases produced by Serratia marcescens and explore the mechanism of antibiotic resistance. METHODS The drug susceptibility testing for 272 strains of S. marcescens was performed by using K-B disc diffusion method; the ESBLs and AmpC were detected by phenotype screening and three dimensional test, the modified Hodge test was adopted for detection of phenotype of carbapenemases with ertapenem as substrate. RESULTS The resistance rates of S. marcescens to ampicillin, cefazolin, and piperacillin were above 80. 0% , the resistance rates to imipenem and cefoperazone/sulbactam were lower than 10. 0%; among 272 strains of S. marcescens, there were 30 strains of ESBLs-producing S. marcescens detected with the detection rate of 11. 0%, there were 41 strains of AmpC-producing S. marcescens detected with the detection rate of 15.1%, there were 15 strains of both ESBLs and AmpC-producing S. marcescens with the detection rate of 5.5%; Hodge test showed that there were 15 strains positive. CONCLUSION The drug resistance rate of S. marcescens to commonly used antibiotics is high, the antibiotic resistance is related to the production of AmpC, ESBLs, or carbapenemases, so we should strengthen the detection and surveillance in clinical laboratory.%目的 了解褪色沙雷菌β-内酰胺酶的产生情况并探讨其耐药机制.方法 采用K-B纸片扩散法对临床分离的272株褪色沙雷菌进行药敏试验;用表型筛选及三维试验法进行ESBLs和AmpC酶检测;采用改良的Hodge试验,以厄他培南为指示药物进行碳青霉烯酶表型检测.结果 褪色沙雷菌对氨苄西林、头孢唑林和哌拉西林的耐药率均>80.0%,对亚胺培南、头孢哌酮/舒巴坦的耐药率<10.0%;272株褪色沙雷菌中产ESBLs菌30株,检出率为11.0%,产AmpC酶菌41株,检出率为15.1%,同时产ESBLs和AmpC酶15株,检出率为5.5%;Hodge试验结果,有15株为阳性.结论 褪色沙雷菌对常用抗菌药

  20. Fractional calculus in bioengineering.

    Science.gov (United States)

    Magin, Richard L

    2004-01-01

    Fractional calculus (integral and differential operations of noninteger order) is not often used to model biological systems. Although the basic mathematical ideas were developed long ago by the mathematicians Leibniz (1695), Liouville (1834), Riemann (1892), and others and brought to the attention of the engineering world by Oliver Heaviside in the 1890s, it was not until 1974 that the first book on the topic was published by Oldham and Spanier. Recent monographs and symposia proceedings have highlighted the application of fractional calculus in physics, continuum mechanics, signal processing, and electromagnetics, but with few examples of applications in bioengineering. This is surprising because the methods of fractional calculus, when defined as a Laplace or Fourier convolution product, are suitable for solving many problems in biomedical research. For example, early studies by Cole (1933) and Hodgkin (1946) of the electrical properties of nerve cell membranes and the propagation of electrical signals are well characterized by differential equations of fractional order. The solution involves a generalization of the exponential function to the Mittag-Leffler function, which provides a better fit to the observed cell membrane data. A parallel application of fractional derivatives to viscoelastic materials establishes, in a natural way, hereditary integrals and the power law (Nutting/Scott Blair) stress-strain relationship for modeling biomaterials. In this review, I will introduce the idea of fractional operations by following the original approach of Heaviside, demonstrate the basic operations of fractional calculus on well-behaved functions (step, ramp, pulse, sinusoid) of engineering interest, and give specific examples from electrochemistry, physics, bioengineering, and biophysics. The fractional derivative accurately describes natural phenomena that occur in such common engineering problems as heat transfer, electrode/electrolyte behavior, and sub

  1. Social Trust and Fractionalization:

    DEFF Research Database (Denmark)

    Bjørnskov, Christian

    2008-01-01

    This paper takes a closer look at the importance of fractionalization for the creation of social trust. It first argues that the determinants of trust can be divided into two categories: those affecting individuals' trust radii and those affecting social polarization. A series of estimates using...... a much larger country sample than in previous literature confirms that fractionalization in the form of income inequality and political diversity adversely affects social trust while ethnic diversity does not. However, these effects differ systematically across countries, questioning standard...... interpretations of the influence of fractionalization on trust....

  2. Resistance to Cefepime and Cefpirome Due to a 4-Amino-Acid Deletion in the Chromosome-Encoded AmpC β-Lactamase of a Serratia marcescens Clinical Isolate

    Science.gov (United States)

    Mammeri, Hedi; Poirel, Laurent; Bemer, Pascal; Drugeon, Henri; Nordmann, Patrice

    2004-01-01

    A multiresistant Serratia marcescens strain, HD, isolated from a patient with a urinary tract infection, was resistant to amino-, carboxy-, and ureidopenicillins, ceftazidime, and cefepime and was susceptible to cefotaxime and ceftriaxone, according to the guidelines of the NCCLS. No synergy was found between expanded-spectrum cephalosporins and clavulanic acid, according to the double-disk synergy test. The blaAmpC gene of the strain was amplified by PCR and cloned into Escherichia coli DH10B, giving rise to high-level resistance to ceftazidime, cefepime, and cefpirome. Sequencing analysis revealed that the blaAmpC gene from S. marcescens HD had a 12-nucleotide deletion compared to the blaAmpC gene from reference strain S. marcescens S3, leading to a 4-amino-acid deletion located in the H-10 helix of the β-lactamase. Kinetic analysis showed that this enzyme significantly hydrolyzed ceftazidime, cefepime, and cefpirome. This work underlined that resistance to the latest expanded-spectrum cephalosporins may be mediated by structurally modified AmpC-type β-lactamases. PMID:14982755

  3. Resistance to cefepime and cefpirome due to a 4-amino-acid deletion in the chromosome-encoded AmpC beta-lactamase of a Serratia marcescens clinical isolate.

    Science.gov (United States)

    Mammeri, Hedi; Poirel, Laurent; Bemer, Pascal; Drugeon, Henri; Nordmann, Patrice

    2004-03-01

    A multiresistant Serratia marcescens strain, HD, isolated from a patient with a urinary tract infection, was resistant to amino-, carboxy-, and ureidopenicillins, ceftazidime, and cefepime and was susceptible to cefotaxime and ceftriaxone, according to the guidelines of the NCCLS. No synergy was found between expanded-spectrum cephalosporins and clavulanic acid, according to the double-disk synergy test. The bla(AmpC) gene of the strain was amplified by PCR and cloned into Escherichia coli DH10B, giving rise to high-level resistance to ceftazidime, cefepime, and cefpirome. Sequencing analysis revealed that the bla(AmpC) gene from S. marcescens HD had a 12-nucleotide deletion compared to the bla(AmpC) gene from reference strain S. marcescens S3, leading to a 4-amino-acid deletion located in the H-10 helix of the beta-lactamase. Kinetic analysis showed that this enzyme significantly hydrolyzed ceftazidime, cefepime, and cefpirome. This work underlined that resistance to the latest expanded-spectrum cephalosporins may be mediated by structurally modified AmpC-type beta-lactamases.

  4. 粘质沙雷氏菌几丁质酶chiB基因的克隆与序列分析%Cloning and Sequence Analysis of Serratia marcescens Chitinase chiB Gene

    Institute of Scientific and Technical Information of China (English)

    叶辉; 程备久; 朱苏文; 甘德芳; 冯春

    2007-01-01

    采用改进的方法提取粘质沙雷氏菌基因组DNA,通过PCR扩增,得到大小为1500 bp特异性DNA片段(chiB基因),以pUC18质粒构建了pUC-chiB克隆载体,转化至感受态细胞E.coli DH5a培养,并筛选出重组质粒.经测序分析,证明克隆片段与文献报道相一致.%The genome DNA was extracted from serratia marcescens by improved method .A special fragment about 1 500 bp length was cloned from serratia marcescens genome DNA by Polymerasw Chain Reaction (PCR) amplification. Vector Puc-CHIb was constructed through ligating the fragment into the plasmid pUC18 and transformed into E. Coli DH5α. Through screening of recombinants and sequence analysis of it, the result showed that the cloned DNA fragment was chitinase chiB gene of Serratia marcescens which was the same as reported.

  5. Research and detection of Serratia marcescens using molecular biology in dairy products%乳制品中粘质沙雷菌的分子生物学检测方法研究

    Institute of Scientific and Technical Information of China (English)

    李晓虹; 黄逸男; 韩伟; 张琳; 阎东丽

    2009-01-01

    目的:建立一种利用PCR方法快速准确的从乳制品中检测粘质沙雷菌(Serratia marcescens)的分子生物学方法.方法:从增菌液中提取DNA,针对粘质沙雷菌(S.marcescens)16s rRNA区域的基因设计特异性引物,进行PCR检测,并对其进行特异性和灵敏性的研究.结果:通过PCR反应,得到长度为417 bp特异性的扩增产物.结论:实验结果表明,本研究建立的从乳制品中检测粘质沙雷菌(S.marcescens)PCR方法,较常规的检测方法简便、快速、灵敏度高,灵敏度可达70 cfu/ml.

  6. Discrete fractional calculus

    CERN Document Server

    Goodrich, Christopher

    2015-01-01

    This text provides the first comprehensive treatment of the discrete fractional calculus. Experienced researchers will find the text useful as a reference for discrete fractional calculus and topics of current interest. Students who are interested in learning about discrete fractional calculus will find this text to provide a useful starting point. Several exercises are offered at the end of each chapter and select answers have been provided at the end of the book. The presentation of the content is designed to give ample flexibility for potential use in a myriad of courses and for independent study. The novel approach taken by the authors includes a simultaneous treatment of the fractional- and integer-order difference calculus (on a variety of time scales, including both the usual forward and backwards difference operators). The reader will acquire a solid foundation in the classical topics of the discrete calculus while being introduced to exciting recent developments, bringing them to the frontiers of the...

  7. Fractional Derivative Cosmology

    CERN Document Server

    Roberts, Mark D

    2009-01-01

    The degree by which a function can be differentiated need not be restricted to integer values. Usually most of the field equations of physics are taken to be second order, curiosity asks what happens if this is only approximately the case and the field equations are nearly second order. For Robertson-Walker cosmology there is a simple fractional modification of the Friedman and conservation equations. In general fractional gravitational equations similar to Einstein's are hard to define as this requires fractional derivative geometry. What fractional derivative geometry might entail is briefly looked at and it turns out that even asking very simple questions in two dimensions leads to ambiguous or intractable results. A two dimensional line element which depends on the Gamma-function is looked at.

  8. Intracellular Cadmium Isotope Fractionation

    Science.gov (United States)

    Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

    2011-12-01

    Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

  9. New Fractional Complex Transform for Conformable Fractional Partial Differential Equations

    Directory of Open Access Journals (Sweden)

    Çenesiz Y.

    2016-12-01

    Full Text Available Conformable fractional complex transform is introduced in this paper for converting fractional partial differential equations to ordinary differential equations. Hence analytical methods in advanced calculus can be used to solve these equations. Conformable fractional complex transform is implemented to fractional partial differential equations such as space fractional advection diffusion equation and space fractional telegraph equation to obtain the exact solutions of these equations.

  10. 粘质沙雷菌医院感染现状及耐药性分析%The status of nosocomial infection and antibacterial drug resistance of Serratia marcescens

    Institute of Scientific and Technical Information of China (English)

    江艳; 李珂; 何萍

    2014-01-01

    目的 了解粘质沙雷菌医院感染的分布特点及对常用抗菌药物的耐药性,为临床抗感染治疗提供依据.方法 对四川省科学城医院2010-2013年分离的107株粘质沙雷菌进行细菌的分布和耐药性分析.结果 107株粘质沙雷菌主要来自呼吸道(87.9%).病房分布主要来自老年病房(39.3%)、呼吸内科(17.8%)和重症监护室(15.0%).耐药率低于10%的抗菌药物有阿米卡星、头孢替坦、头孢吡肟、头孢他啶、哌拉西林/他唑巴坦.2010-2012年间均未检出耐亚胺培南的粘质沙雷菌,2013年对亚胺培南的耐药率增至18.9%.亚胺培南耐药的粘质沙雷菌对抗菌药物耐药率亦明显增高.结论 粘质沙雷菌是引起医院感染的常见病原菌,其分离数逐年增加,对常用抗菌药物耐药率呈逐渐增高趋势,临床医生应重视.%Objective To investigate the clinical distribution and drug resistance of Serratia marcescens in order to provide reasonable basis for clinical therapy.Methods Retrospective analysis was performed on the clinical distribution and drug resistance of hospital-acquired Serratia marcescens form 2010 to 2013.Results The isolating rate of Serratia marcescens mainly from sputum was 87.9%.The hospital-acquired Serratia marcescens was mainly distributed in geriatrics department (39.3%),respiratory department (17.8%),and intensive care unit (15.0%).Antibiotics with resistant rate less than 10% were amikacin,cefotetan,cefepime,ceftazidime,and pieperacillin-tazobactam.Imipenem-resistant Serratia marcescens had not been detected from 2010 to 2012,the resistant rate to imipenem increased to 18.9% in 2013.Imipenem-resistant Seriatia marcescens also increased obviously.Conclusion Serratia marcescens is the major conditional pathogenic bacterium during hospital infections at present,the number of isolates have been increased in recent years,and its resistant trend to antibiotics is gradually increasing.The clinical

  11. Fractional Vortices and Lumps

    CERN Document Server

    Eto, Minoru; Gudnason, Sven Bjarke; Konishi, Kenichi; Nagashima, Takayuki; Nitta, Muneto; Ohashi, Keisuke; Vinci, Walter

    2009-01-01

    We study what might be called fractional vortices, vortex configurations with the minimum winding from the viewpoint of their topological stability, but which are characterized by various notable substructures in the transverse energy distribution. The fractional vortices occur in diverse Abelian or non-Abelian generalizations of the Higgs model. The global and local features characterizing these are studied, and we identify the two crucial ingredients for their occurrence - the vacuum degeneracy leading to non-trivial vacuum moduli M, and the BPS nature of the vortices. Fractional vortices are further classified into two kinds. The first type of such vortices appear when M has orbifold Z_n singularities; the second type occurs in systems in which the vacuum moduli space M possesses either a deformed geometry or some singularity. These general features are illustrated with several concrete models.

  12. Fractional-order devices

    CERN Document Server

    Biswas, Karabi; Caponetto, Riccardo; Mendes Lopes, António; Tenreiro Machado, José António

    2017-01-01

    This book focuses on two specific areas related to fractional order systems – the realization of physical devices characterized by non-integer order impedance, usually called fractional-order elements (FOEs); and the characterization of vegetable tissues via electrical impedance spectroscopy (EIS) – and provides readers with new tools for designing new types of integrated circuits. The majority of the book addresses FOEs. The interest in these topics is related to the need to produce “analogue” electronic devices characterized by non-integer order impedance, and to the characterization of natural phenomena, which are systems with memory or aftereffects and for which the fractional-order calculus tool is the ideal choice for analysis. FOEs represent the building blocks for designing and realizing analogue integrated electronic circuits, which the authors believe hold the potential for a wealth of mass-market applications. The freedom to choose either an integer- or non-integer-order analogue integrator...

  13. Fractional and noncommutative spacetimes

    Science.gov (United States)

    Arzano, Michele; Calcagni, Gianluca; Oriti, Daniele; Scalisi, Marco

    2011-12-01

    We establish a mapping between fractional and noncommutative spacetimes in configuration space. Depending on the scale at which the relation is considered, there arise two possibilities. For a fractional spacetime with log-oscillatory measure, the effective measure near the fundamental scale determining the log-period coincides with the nonrotation-invariant but cyclicity-preserving measure of κ-Minkowski spacetime. At scales larger than the log-period, the fractional measure is averaged and becomes a power law with real exponent. This can be also regarded as the cyclicity-inducing measure in a noncommutative spacetime defined by a certain nonlinear algebra of the coordinates, which interpolates between κ-Minkowski and canonical spacetime. These results are based upon a braiding formula valid for any nonlinear algebra which can be mapped onto the Heisenberg algebra.

  14. Fractional and noncommutative spacetimes

    CERN Document Server

    Arzano, Michele; Oriti, Daniele; Scalisi, Marco

    2011-01-01

    We establish a mapping between fractional and noncommutative spacetimes in configuration space. Depending on the scale at which the relation is considered, there arise two possibilities. For a fractional spacetime with log-oscillatory measure, the effective measure near the fundamental scale determining the log-period coincides with the non-rotation-invariant but cyclicity-preserving measure of \\kappa-Minkowski. At scales larger than the log-period, the fractional measure is averaged and becomes a power-law with real exponent. This can be also regarded as the cyclicity-inducing measure in a noncommutative spacetime defined by a certain nonlinear algebra of the coordinates, which interpolates between \\kappa-Minkowski and canonical spacetime. These results are based upon a braiding formula valid for any nonlinear algebra which can be mapped onto the Heisenberg algebra.

  15. Fractional standard map

    Energy Technology Data Exchange (ETDEWEB)

    Edelman, Mark, E-mail: edelman@cims.nyu.ed [Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, NY 10012 (United States)] [Department of Physics, Stern College at Yeshiva University, 245 Lexington Avenue, New York, NY 10016 (United States); Tarasov, Vasily E. [Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, NY 10012 (United States)] [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991 (Russian Federation)

    2009-12-28

    Properties of the phase space of the standard map with memory are investigated. This map was obtained from a kicked fractional differential equation. Depending on the value of the map parameter and the fractional order of the derivative in the original differential equation, this nonlinear dynamical system demonstrates attractors (fixed points, stable periodic trajectories, slow converging and slow diverging trajectories, ballistic trajectories, and fractal-like structures) and/or chaotic trajectories. At least one type of fractal-like sticky attractors in the chaotic sea was observed.

  16. Pseudomonas aeruginosa ExlA and Serratia marcescens ShlA trigger cadherin cleavage by promoting calcium influx and ADAM10 activation.

    Science.gov (United States)

    Reboud, Emeline; Bouillot, Stéphanie; Patot, Sabine; Béganton, Benoît; Attrée, Ina; Huber, Philippe

    2017-08-23

    Pore-forming toxins are potent virulence factors secreted by a large array of bacteria. Here, we deciphered the action of ExlA from Pseudomonas aeruginosa and ShlA from Serratia marcescens on host cell-cell junctions. ExlA and ShlA are two members of a unique family of pore-forming toxins secreted by a two-component secretion system. Bacteria secreting either toxin induced an ExlA- or ShlA-dependent rapid cleavage of E-cadherin and VE-cadherin in epithelial and endothelial cells, respectively. Cadherin proteolysis was executed by ADAM10, a host cell transmembrane metalloprotease. ADAM10 activation is controlled in the host cell by cytosolic Ca2+ concentration. We show that Ca2+ influx, induced by ExlA or ShlA pore formation in the plasma membrane, triggered ADAM10 activation, thereby leading to cadherin cleavage. Our data suggest that ADAM10 is not a cellular receptor for ExlA and ShlA, further confirming that ADAM10 activation occurred via Ca2+ signalling. In conclusion, ExlA- and ShlA-secreting bacteria subvert a regulation mechanism of ADAM10 to activate cadherin shedding, inducing intercellular junction rupture, cell rounding and loss of tissue barrier integrity.

  17. Stereoselective synthesis of (R)-phenylephrine using recombinant Escherichia coli cells expressing a novel short-chain dehydrogenase/reductase gene from Serratia marcescens BCRC 10948.

    Science.gov (United States)

    Peng, Guan-Jhih; Kuan, Yi-Chia; Chou, Hsiao-Yi; Fu, Tze-Kai; Lin, Jia-Shin; Hsu, Wen-Hwei; Yang, Ming-Te

    2014-01-20

    (R)-Phenylephrine [(R)-PE] is an α1-adrenergic receptor agonist and is widely used as a nasal decongestant to treat the common cold without the side effects of other ephedrine adrenergic drugs. We identified a short-chain dehydrogenase/reductase (SM_SDR) from Serratia marcescens BCRC 10948 that was able to convert 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) into (R)-PE. The SM_SDR used NADPH and NADH as cofactors with specific activities of 17.35±0.71 and 5.57±0.07mU/mg protein, respectively, at 30°C and pH 7.0, thereby indicating that this enzyme could be categorized as an NADPH-preferring short-chain dehydrogenase/reductase. Escherichia coli strain BL21 (DE3) expressing SM_SDR could convert HPMAE into (R)-PE with more than 99% enantiomeric excess. The productivity and conversion yield were 0.57mmolPE/lh and 51.06%, respectively, using 10mM HPMAE. Fructose was the most effective carbon source for the conversion of HPMAE to (R)-PE.

  18. Complete Sequence of Four Multidrug-Resistant MOBQ1 Plasmids Harboring blaGES-5 Isolated from Escherichia coli and Serratia marcescens Persisting in a Hospital in Canada.

    Science.gov (United States)

    Boyd, David; Taylor, Geoffrey; Fuller, Jeff; Bryce, Elizabeth; Embree, Joanne; Gravel, Denise; Katz, Kevin; Kibsey, Pamela; Kuhn, Magdalena; Langley, Joanne; Mataseje, Laura; Mitchell, Robyn; Roscoe, Diane; Simor, Andrew; Thomas, Eva; Turgeon, Nathalie; Mulvey, Michael

    2015-06-01

    The usefulness of carbapenems for gram-negative infections is becoming compromised by organisms harboring carbapenemases, enzymes which can hydrolyze the drug. Currently KPC (class A), NDM (class B), and OXA-48 types (class D) are the most globally widespread carbapenemases. However, among the GES-type class A extended-spectrum β-lactamases (ESBLs) there are variants that hydrolyze carbapenems, with blaGES-5 being the most common. Two Escherichia coli and two Serratia marcescens harboring blaGES-5 on plasmids were isolated by the Canadian Nosocomial Infection Surveillance Program (CNISP) from four different patients in a single hospital over a 2-year period. Complete sequencing of the blaGES-5 plasmids indicated that all four had nearly identical backbones consisting of genes for replication, partitioning, and stability, but contained variant accessory regions consisting of mobile elements and antimicrobial resistance genes. The plasmids were of a novel replicon type, but belonged to the MOBQ1 group based on relaxase sequences, and appeared to be mobilizable, but not self-transmissible. Considering the time periods of bacterial isolation, it would appear the blaGES-5 plasmid has persisted in an environmental niche for at least 2 years in the hospital. This has implications for infection control and clinical care when it is transferred to clinically relevant gram-negative organisms.

  19. Biogenesis of outer membrane vesicles in Serratia marcescens is thermoregulated and can be induced by activation of the Rcs phosphorelay system.

    Science.gov (United States)

    McMahon, Kenneth J; Castelli, Maria E; García Vescovi, Eleonora; Feldman, Mario F

    2012-06-01

    Outer membrane vesicles (OMVs) have been identified in a wide range of bacteria, yet little is known of their biogenesis. It has been proposed that OMVs can act as long-range toxin delivery vectors and as a novel stress response. We have found that the formation of OMVs in the gram-negative opportunistic pathogen Serratia marcescens is thermoregulated, with a significant amount of OMVs produced at 22 or 30°C and negligible quantities formed at 37°C under laboratory conditions. Inactivation of the synthesis of the enterobacterial common antigen (ECA) resulted in a hypervesiculation phenotype, supporting the hypothesis that OMVs are produced in response to stress. We demonstrate that the phenotype can be reversed to wild-type (WT) levels upon the loss of the Rcs phosphorelay response regulator RcsB, but not RcsA, suggesting a role for the Rcs phosphorelay in the production of OMVs. MS fingerprinting of the OMVs provided evidence of cargo selection within wild-type cells, suggesting a possible role for Serratia OMVs in toxin delivery. In addition, OMV-associated cargo proved toxic upon injection into the haemocoel of Galleria mellonella larvae. These experiments demonstrate that OMVs are the result of a regulated process in Serratia and suggest that OMVs could play a role in virulence.

  20. 黏质沙雷氏菌产几丁质酶的发酵工艺优化%Culture Parameter Optimization of Chitinase Production by Serratia marcescens

    Institute of Scientific and Technical Information of China (English)

    施腾鑫; 刘嘉; 贺淹才

    2010-01-01

    利用均匀设计法,优化一株黏质沙雷氏菌(Serratia marcescens)产几丁质酶培养基的组分;同时,利用正交设计法优化其摇瓶发酵产酶的条件. 研究结果表明,最佳培养基组分(质量分数):0.504%胶体几丁质,1.178%酵母粉,0.025%MgSO4·7H2O,0.095%K2HPO4 ,0.001%FeSO4·7H2O,0.005%山梨醇,0.030%KH2PO4;最佳摇瓶发酵工艺条件:培养时间为48 h,发酵温度为30 ℃,初始pH值为9.0,装液量为30 mL,接种量为1% 在此优化条件下,酶活力可达9.39 μkat·L-1,比未优化的产酶条件下酶活力提高了81.6%.

  1. From Complex Fractional Fourier Transform to Complex Fractional Radon Transform

    Institute of Scientific and Technical Information of China (English)

    FAN Hong-Yi; JIANG Nian-Quan

    2004-01-01

    We show that for n-dimensional complex fractional Fourier transform the corresponding complex fractional Radon transform can also be derived, however, it is different from the direct product of two n-dimensional real fractional Radon transforms. The complex fractional Radon transform of two-mode Wigner operator is calculated.

  2. Avoidance of Fractions.

    Science.gov (United States)

    Hart, Kathleen; Kerslake, Daphne

    The Concepts in Secondary Mathematics and Science (CSMS) and Strategies and Errors in Secondary Mathematics (SESM) research projects based at Chelsa College, England, have shown the marked reluctance of secondary school students to use fractions when solving mathematical problems, even though they have been taught the topic for a number of years.…

  3. Brewing with fractionated barley

    NARCIS (Netherlands)

    Donkelaar, van L.H.G.

    2016-01-01

    Brewing with fractionated barley Beer is a globally consumed beverage, which is produced from malted barley, water, hops and yeast. In recent years, the use of unmalted barley and exogenous enzymes have become more popular because they enable simpler processing and reduced environmental impact. Raw

  4. Ramping up on Fractions

    Science.gov (United States)

    Stephens, Ana C.; Bottge, Brian A.; Rueda, Enrique

    2009-01-01

    This article describes a technology-based and hands-on instructional intervention designed to advance middle school students' understandings of fractions. This problem-solving experience is based on the principles of Enhanced Anchored Instruction (EAI) and proved instructionally worthwhile and motivating to teachers and students in both inclusive …

  5. Sweet Work with Fractions

    Science.gov (United States)

    Vinogradova, Natalya; Blaine, Larry

    2013-01-01

    Almost everyone loves chocolate. However, the same cannot be said about fractions, which are loved by markedly fewer. Middle school students tend to view them with wary respect, but little affection. The authors attempt to sweeten the subject by describing a type of game involving division of chocolate bars. The activity they describe provides a…

  6. Momentum fractionation on superstrata

    Science.gov (United States)

    Bena, Iosif; Martinec, Emil; Turton, David; Warner, Nicholas P.

    2016-05-01

    Superstrata are bound states in string theory that carry D1, D5, and momentum charges, and whose supergravity descriptions are parameterized by arbitrary functions of (at least) two variables. In the D1-D5 CFT, typical three-charge states reside in high-degree twisted sectors, and their momentum charge is carried by modes that individually have fractional momentum. Understanding this momentum fractionation holographically is crucial for understanding typical black-hole microstates in this system. We use solution-generating techniques to add momentum to a multi-wound supertube and thereby construct the first examples of asymptotically-flat superstrata. The resulting supergravity solutions are horizonless and smooth up to well-understood orbifold singularities. Upon taking the AdS3 decoupling limit, our solutions are dual to CFT states with momentum fractionation. We give a precise proposal for these dual CFT states. Our construction establishes the very nontrivial fact that large classes of CFT states with momentum fractionation can be realized in the bulk as smooth horizonless supergravity solutions.

  7. Fractional statistics and confinement

    CERN Document Server

    Gaete, P; Gaete, Patricio; Wotzasek, Clovis

    2004-01-01

    It is shown that a pointlike composite having charge and magnetic moment displays a confining potential for the static interaction while simultaneously obeying fractional statistics in a pure gauge theory in three dimensions, without a Chern-Simons term. This result is distinct from the Maxwell-Chern-Simons theory that shows a screening nature for the potential.

  8. Brewing with fractionated barley

    NARCIS (Netherlands)

    Donkelaar, van L.H.G.

    2016-01-01

    Brewing with fractionated barley Beer is a globally consumed beverage, which is produced from malted barley, water, hops and yeast. In recent years, the use of unmalted barley and exogenous enzymes have become more popular because they enable simpler processing and reduced environmental impact. Raw

  9. Fractional Differential Equation

    Directory of Open Access Journals (Sweden)

    Moustafa El-Shahed

    2007-01-01

    where 2<α<3 is a real number and D0+α is the standard Riemann-Liouville fractional derivative. Our analysis relies on Krasnoselskiis fixed point theorem of cone preserving operators. An example is also given to illustrate the main results.

  10. Creating, Naming, and Justifying Fractions

    Science.gov (United States)

    Siebert, Daniel; Gaskin, Nicole

    2006-01-01

    For students to develop meaningful conceptions of fractions and fraction operations, they need to think of fractions in terms other than as just whole-number combinations. In this article, we suggest two powerful images for thinking about fractions that move beyond whole-number reasoning. (Contains 5 figures.)

  11. -Dimensional Fractional Lagrange's Inversion Theorem

    Directory of Open Access Journals (Sweden)

    F. A. Abd El-Salam

    2013-01-01

    Full Text Available Using Riemann-Liouville fractional differential operator, a fractional extension of the Lagrange inversion theorem and related formulas are developed. The required basic definitions, lemmas, and theorems in the fractional calculus are presented. A fractional form of Lagrange's expansion for one implicitly defined independent variable is obtained. Then, a fractional version of Lagrange's expansion in more than one unknown function is generalized. For extending the treatment in higher dimensions, some relevant vectors and tensors definitions and notations are presented. A fractional Taylor expansion of a function of -dimensional polyadics is derived. A fractional -dimensional Lagrange inversion theorem is proved.

  12. Fractional lattice charge transport

    Science.gov (United States)

    Flach, Sergej; Khomeriki, Ramaz

    2017-01-01

    We consider the dynamics of noninteracting quantum particles on a square lattice in the presence of a magnetic flux α and a dc electric field E oriented along the lattice diagonal. In general, the adiabatic dynamics will be characterized by Bloch oscillations in the electrical field direction and dispersive ballistic transport in the perpendicular direction. For rational values of α and a corresponding discrete set of values of E(α) vanishing gaps in the spectrum induce a fractionalization of the charge in the perpendicular direction - while left movers are still performing dispersive ballistic transport, the complementary fraction of right movers is propagating in a dispersionless relativistic manner in the opposite direction. Generalizations and the possible probing of the effect with atomic Bose-Einstein condensates and photonic networks are discussed. Zak phase of respective band associated with gap closing regime has been computed and it is found converging to π/2 value. PMID:28102302

  13. Fractions in elementary education

    CERN Document Server

    Quinn, Frank

    2013-01-01

    This paper is one of a series in which elementary-education practice is analyzed by comparison with the history of mathematics, mathematical structure, modern practice, and (occasionally) cognitive neuroscience. The primary concerns are: Why do so many children find elementary mathematics difficult? And, why are the ones who succeed still so poorly prepared for college material needed for technical careers? The answer provided by conventional wisdom is essentially that mathematics is difficult. Third-graders are not developmentally ready for the subtlety of fractions, for instance, and even high-performing students cannot be expected to develop the skills of experienced users. However we will see that this is far from the whole story and is probably wrong: elementary-education fractions are genuinely harder and less effective than the version employed by experienced users. Experts discard at least 90% of what is taught in schools. Our educational system is actually counterproductive for skill development, and...

  14. Testing Fractional Action Cosmology

    CERN Document Server

    Shchigolev, V K

    2015-01-01

    The present work deals with a combined test of the so-called Fractional Action Cosmology (FAC) on the example of a specific model obtained by the author earlier. In this model, the effective cosmological term is proportional to the Hubble parameter squared through the so-called kinematic induction. The reason of studying this cosmological model could be explained by its ability to describe two periods of accelerated expansion, that is in agreement with the recent observations and the cosmological inflation paradigm. First of all, we put our model through the theoretical tests that gives a general conception of the influence of the model parameters on its behavior. Then, we obtain some restrictions on the principal parameters of the model, including the fractional index, by means of the observational data. Finally, the cosmography parameters and the observational data compared to the theoretical predictions are presented both analytically and graphically.

  15. Testing fractional action cosmology

    Science.gov (United States)

    Shchigolev, V. K.

    2016-08-01

    The present work deals with a combined test of the so-called Fractional Action Cosmology (FAC) on the example of a specific model obtained by the author earlier. In this model, the effective cosmological term is proportional to the Hubble parameter squared through the so-called kinematic induction. The reason of studying this cosmological model could be explained by its ability to describe two periods of accelerated expansion, that is in agreement with the recent observations and the cosmological inflation paradigm. First of all, we put our model through the theoretical tests, which gives a general conception of the influence of the model parameters on its behavior. Then, we obtain some restrictions on the principal parameters of the model, including the fractional index, by means of the observational data. Finally, the cosmography parameters and the observational data compared to the theoretical predictions are presented both analytically and graphically.

  16. Nonlinear fractional relaxation

    Indian Academy of Sciences (India)

    A Tofighi

    2012-04-01

    We define a nonlinear model for fractional relaxation phenomena. We use -expansion method to analyse this model. By studying the fundamental solutions of this model we find that when → 0 the model exhibits a fast decay rate and when → ∞ the model exhibits a power-law decay. By analysing the frequency response we find a logarithmic enhancement for the relative ratio of susceptibility.

  17. Brewing with fractionated barley

    OpenAIRE

    Donkelaar, van, CC René

    2016-01-01

    Brewing with fractionated barley Beer is a globally consumed beverage, which is produced from malted barley, water, hops and yeast. In recent years, the use of unmalted barley and exogenous enzymes have become more popular because they enable simpler processing and reduced environmental impact. Raw barley, however, contains less endogenous enzymes and more undesired components for the use of beer brewing, compared to malted barley.  The overall aim of this thesis is to investigate how ba...

  18. Momentum Fractionation on Superstrata

    CERN Document Server

    Bena, Iosif; Turton, David; Warner, Nicholas P

    2016-01-01

    Superstrata are bound states in string theory that carry D1, D5, and momentum charges, and whose supergravity descriptions are parameterized by arbitrary functions of (at least) two variables. In the D1-D5 CFT, typical three-charge states reside in high-degree twisted sectors, and their momentum charge is carried by modes that individually have fractional momentum. Understanding this momentum fractionation holographically is crucial for understanding typical black-hole microstates in this system. We use solution-generating techniques to add momentum to a multi-wound supertube and thereby construct the first examples of asymptotically-flat superstrata. The resulting supergravity solutions are horizonless and smooth up to well-understood orbifold singularities. Upon taking the AdS3 decoupling limit, our solutions are dual to CFT states with momentum fractionation. We give a precise proposal for these dual CFT states. Our construction establishes the very nontrivial fact that large classes of CFT states with mom...

  19. 医院感染褪色沙雷菌的临床分布与耐药性分析%Clinical distribution and drug resistance of Serratia marcescens causing nosocomial infection

    Institute of Scientific and Technical Information of China (English)

    王蓓; 刘红; 邹雪; 蒋晓飞

    2015-01-01

    OBJECTIVE To investigate the clinical distribution of Serratia marcescens causing nosocomial infections and observe the drug resistance to the commonly used antibiotics so as to guide the reasonable clinical use of antibi‐otics .METHODS A total of 434 strains of S .marcescens were isolated from the submitted specimens that were ob‐tained from the patients who were hospitalized Huashan Hospital from Jan 2009 to Dec 2013 .The drug susceptibil‐ity testing and the statistical analysis were performed .The drug resistance rates were analyzed with the use of Whonet5 .4 software .RESULTS Totally 434 strains of S .marcescens were isolated from the submitted specimens , most of which were isolated from the sputum ,wound ,urine ,and secretions specimens .The drug susceptibility rates of the S .marcescens to cefoperazone‐sulbactam ,piperacillin‐tazobactam ,imipenem ,meropenem ,and ertap‐enem were 74 .4% ,82 .5% ,84 .8% ,90 .2% ,and 88 .9% ,respectively ;while the drug resistance rate of the S . marcescens to carbapenems was increased year by year and continued to show an upward trend .CONCLUSION The drug resistance rate of the S .marcescens to carbapenems shows an upward trend ,therefore ,it is necessary for the hospital to monitor the nosocomial infections ,analyze the drug resistance of the pathogens ,reasonably use antibi‐otics based on the results of the drug susceptibility testing ,and curb the spread of drug‐resistant strains .%目的:了解患者医院感染褪色沙雷菌的临床分布特点及对常用抗菌药物的耐药性变化,指导临床合理使用抗菌药物。方法收集2009年1月-2013年12月华山医院住院患者送检标本分离出的褪色沙雷菌434株,进行药敏试验及统计分析;使用世界卫生组织耐药监控网提供的Whonet 5.4软件进行耐药率分析。结果从临床送检标本中共检出434株褪色沙雷菌,主要分离自痰液、伤口、尿液和分泌物等标本;褪色沙雷菌对头

  20. Application of Serratia Marcescens in Immunomodulatory and Anti-tumor%粘质沙雷氏菌在免疫调节及抗肿瘤方面的应用

    Institute of Scientific and Technical Information of China (English)

    张帅; 卢磊; 王靖瑶; 王天女

    2015-01-01

    Today,the tumor is still major threats to human health, and the chemical treatment of the tumor treatment would kill the tumor cells and cause irreversible damage to normal cells, resulting in tumor therapy research focus gradually in low toxic drugs, such as polysaccharide. Lipopolysaccharides of bacterium prodigiosum was extracted from Serratia marcescens, it has good function in immunity and anti-tumor, and its toxicity is lower than other bacterial endotoxin toxicity, more suitable for relevant treatment.This arti-cle focuses on serratia marcescens related physical and chemical properties and its secondary metabolites, Serratia marcescens fat polysaccharide extraction as well as in the role of the medicine.%时至今日,肿瘤依然人类健康的重大威胁,而治疗肿瘤的化学治疗方法会在杀死肿瘤细胞的同时对正常细胞造成不可逆的损害,由此在肿瘤治疗的研究重心逐步转向多糖类等低毒害药物上。从粘质沙雷氏菌细胞壁提取出的灵杆菌脂多糖有较好的免疫调节和抗肿瘤作用,且灵杆菌脂多糖毒性比其他细菌内毒素毒性要低,更适合用于相关治疗。本文将重点介绍粘质沙雷氏菌相关理化性质及其次生代谢产物,粘质沙雷氏菌脂多糖的提取以及在医学方面的作用。

  1. Fractional random walk lattice dynamics

    CERN Document Server

    Michelitsch, Thomas; Riascos, Alejandro Perez; Nowakowski, Andrzeij; Nicolleau, Franck

    2016-01-01

    We analyze time-discrete and continuous `fractional' random walks on undirected regular networks with special focus on cubic periodic lattices in $n=1,2,3,..$ dimensions.The fractional random walk dynamics is governed by a master equation involving {\\it fractional powers of Laplacian matrices $L^{\\frac{\\alpha}{2}}$}where $\\alpha=2$ recovers the normal walk.First we demonstrate thatthe interval $0\\textless{}\\alpha\\leq 2$ is admissible for the fractional random walk. We derive analytical expressions for fractional transition matrix and closely related the average return probabilities. We further obtain thefundamental matrix $Z^{(\\alpha)}$, and the mean relaxation time (Kemeny constant) for the fractional random walk.The representation for the fundamental matrix $Z^{(\\alpha)}$ relates fractional random walks with normal random walks.We show that the fractional transition matrix elements exihibit for large cubic $n$-dimensional lattices a power law decay of an $n$-dimensional infinite spaceRiesz fractional deriva...

  2. Brote de bacteriemia por Serratia marcescens en pacientes portadores de catéteres tunelizados en hemodiálisis secundario a colonización de la solución antiséptica. Experiencia en 4 centros

    Directory of Open Access Journals (Sweden)

    José L. Merino

    2016-11-01

    Conclusiones: Las bacteriemias por gérmenes no convencionales deben ponernos sobre aviso para investigar posibles brotes. La aplicación de una solución contaminada por S. marcescens en los catéteres en hemodiálisis fue la vía de bacteriemia. El tratamiento antibiótico intravenoso y el sellado de los catéteres permitió una excelente supervivencia tanto de los pacientes como de los catéteres.

  3. Clinicaldistribution and antibiotic-resistance changes of 121 Serratia marcescens strains%122株粘质沙雷菌临床分布及耐药性变迁

    Institute of Scientific and Technical Information of China (English)

    蒋旻; 焦梅; 赵水娣; 胡慧敏; 吴根容; 赵艳丰

    2013-01-01

    目的 了解粘质沙雷菌感染的分布及耐药性特征,为临床用药提供依据.方法 收集本院2009年-2011年分离的122株粘质沙雷菌的药物敏感性试验结果,进行细菌的分布及耐药性的分析.结果 分离的122株粘质沙雷菌,其中痰标本有87株(占73.1%).粘质沙雷菌分离数不断增加.其耐药率>95%的抗菌素有氨苄西林和头孢唑啉;耐药率为20%~50%的有头孢他啶、头孢噻肟、头孢吡肟、阿米卡星、庆大霉素、哌拉西林/他唑巴坦和复方新诺明;耐药率<15%的有亚胺培南、美罗培南和左旋氧氟沙星.结论 粘质沙雷菌耐药机制复杂,而且对抗生素具有多重耐药性,根据药敏试验合理应用抗菌素十分重要.%Objective To investigate the distribution characteristics and drug resistance of Serratia marcescens,and to provide basis for clinical medication.Methods The drug sensitivity test results of 122 Serratia marcescens isolates from Second Affiliated Hospital of Nanjing Medical University during 2009 and 2011 were collected to analyze the distribution and drug resistance.Results Serratia marcescens were mainly separated from sputum samples (87/ 122,73.1%).The drug resistance rate more than 95% was found in ampicillin and cefazolin,between 20% and 50% was found in ceftazidime,cefotaxime,cefepime,amikacin,gentamicin,piperacillin-tazobactam and trimethoprim-sulfamethoxazole,less than 15% was found in imipenem,meropenem and levofloxacin.Conclusion Due to the complex resistant mechanism and multi-drug resistance to antibiotics of Serratia marcescens,it is very important to rationally use antibiotics according to susceptibility testing results.

  4. Distribution and resistant analysis for acquisition of serratia marcescens in intensive care unit of cancer hospital%肿瘤医院ICU获得性粘质沙雷菌感染的分布及药敏分析

    Institute of Scientific and Technical Information of China (English)

    徐珊玲; 全勇; 熊冠泽; 吴家玉

    2011-01-01

    目的 探讨肿瘤医院重症监护室内获得性粘质沙雷菌感染的分布以及耐药性特征,为临床预防和控制粘质沙雷萄感染提供依据.方法 对我院重症监护室分离的36株粘质沙雷菌的资料进行细菌分布以及耐药性分析.结果 分离的36株粘质沙雷菌,其中痰标本19株(52.8%);粘质沙雷菌对头孢呋肟、头孢噻吩和头孢唑啉等一代和二代头孢菌素耐药率较高;对四代头孢菌素以及亚胺培南、阿米卡星、复方新诺明和环丙沙星的敏感性较好.结论 粘质沙雷菌耐药机制复杂,而且对抗生素具有多重耐药性,根据药敏试验合理应用抗菌素十分重要.%Objective To investigate distribution and resistance for acquired infection of Serratia marcescens in a intensive care unit of cancer hospital, and provide reliable evidence for preventing and monitoring nosocomial Serratia marcescens infection. Methods 36 strains of Serratia marcescens were separated during January 2006 to October 2009. Distribution and resistant analysis were performed. Results Serratia marcescens had much higher antimicrobial resistance to the 1st and 2nd generation cephalosporin. They were all susceptible to imipenem, 4th generation cephalosporin, amikacin, trimethoprim-sulfamethoxazole and ciprofloxacin. Conclusion Ser show multi-drug resistance. It is very important to rationally use antibiotics according to susceptibility testing results.

  5. 粘质沙雷氏菌和红曲霉跨界原生质体融合子的分子鉴定%Molecular identification of the protoplast fusant of Serratia marcescens and Monascus

    Institute of Scientific and Technical Information of China (English)

    周林; 朱爽; 杜嘉妮

    2011-01-01

    目的 应用分子生物学方法鉴定粘质沙雷氏菌和红曲霉原生质体跨界融合子.方法 采用随机扩增多态性分析和功能基因PCR扩增的方法对9个融合子进行分子鉴定.结果 筛选出的6条随机引物对2个亲本和9个融合子的DNA均能扩增出清晰的条带,除第5号融合子和粘质沙雷氏菌的相似指数略低,其余8个融合子和2个亲本的相似指数均大于2个亲本之间的相似指数.红曲霉和9个融合子中均能扩增出红曲霉功能基因mKH的条带,从粘质沙雷氏菌中则未扩增出相应条带.结论 用分子生物学方法证实获得的9个能产红色素的菌株均为粘质沙雷氏菌和红曲霉的跨界融合子.%Objective To identify the inter-kingdom fusants of Senatia marcescens and Monascus with molecular biology method. Methods The random amplified polymorphic DNA ( RAPD) and functional gene amplification assay were employed to identify the nine fusants. Results Distinct DNA fragments were obtained with the screened six random primers from both parent strains and nine fusants. Except the legs similarity between the No. 5 fusant and Serratia marcescens, the similarity between the eight fusants and two parent strains was greater than that between the two parent strains. The functional mkH gene of Monascus can be amplified from the nine fusants and Monascus rubber, but not detected from the DNA of Serratia marcescens. Conclusion The nine pigmented fusants were successfully identified to be the inter-kingdom fusants from Serratia marcescens and Monascus.

  6. Gauge Invariant Fractional Electromagnetic Fields

    CERN Document Server

    Lazo, Matheus Jatkoske

    2011-01-01

    Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators.

  7. Fractional Langevin equation and Riemann-Liouville fractional derivative.

    Science.gov (United States)

    Sau Fa, Kwok

    2007-10-01

    In this present work we consider a fractional Langevin equation with Riemann-Liouville fractional time derivative which modifies the classical Newtonian force, nonlocal dissipative force, and long-time correlation. We investigate the first two moments, variances and position and velocity correlation functions of this system. We also compare them with the results obtained from the same fractional Langevin equation which uses the Caputo fractional derivative.

  8. ISOLATION AND CHARACTERIZATION OF A MOLYBDENUM-REDUCING AND AZO-DYE DECOLORIZING SERRATIA MARCESCENS STRAIN NENI-1 FROM INDONESIAN SOIL

    Directory of Open Access Journals (Sweden)

    Neni Gusmanizar

    2016-01-01

    Full Text Available Heavy metals and organic xenobiotics including dyes are important industrial components with their usage amounting to the millions of tonnes yearly. Their presence in the environment is a serious pollution issue globally. Bioremediation of these pollutants using microbes with multiple detoxification capacity is constantly being sought. In this work we screen the ability of a molybdenum-reducing bacterium isolated from contaminated soil to decolorize various azo and triphenyl methane dyes. The bacterium reduces molybdate to molybdenum blue (Mo-blue optimally at pH 6.0, and temperatures of between 25 and 40oC. Glucose was the best electron donor for supporting molybdate reduction followed by sucrose, trehalose, maltose, d-sorbitol, dmannitol, d-mannose, myo-inositol, glycerol and salicin in descending order. Other requirements include a phosphate concentration of between 5.0 and 7.5 mM and a molybdate concentration between 10 and 20 mM. The absorption spectrum of the Moblue produced was similar to previous Mo-reducing bacterium, and closely resembles a reduced phosphomolybdate. Molybdenum reduction was inhibited by copper, silver and mercury at 2 ppm by 43.8%, 42.3% and 41.7%, respectively. We screen for the ability of the bacterium to decolorize various dyes. The bacterium was able to decolorize the dye Congo Red. Biochemical analysis resulted in a tentative identification of the bacterium as Serratia marcescens strain Neni-1. The ability of this bacterium to detoxify molybdenum and decolorize azo dye makes this bacterium an important tool for bioremediation.

  9. Preheating with fractional powers

    Science.gov (United States)

    Moghaddam, Hossein Bazrafshan; Brandenberger, Robert

    2016-11-01

    We consider preheating in models in which the potential for the inflaton is given by a fractional power, as is the case in axion monodromy inflation. We assume a standard coupling between the inflaton field and a scalar matter field. We find that in spite of the fact that the oscillation of the inflaton about the field value which minimizes the potential is anharmonic, there is nevertheless a parametric resonance instability, and we determine the Floquet exponent which describes this instability as a function of the parameters of the inflaton potential.

  10. Fractional cointegration rank estimation

    DEFF Research Database (Denmark)

    Lasak, Katarzyna; Velasco, Carlos

    We consider cointegration rank estimation for a p-dimensional Fractional Vector Error Correction Model. We propose a new two-step procedure which allows testing for further long-run equilibrium relations with possibly different persistence levels. The fi…rst step consists in estimating......-likelihood ratio test of no-cointegration on the estimated p - r common trends that are not cointegrated under the null. The cointegration degree is re-estimated in the second step to allow for new cointegration relationships with different memory. We augment the error correction model in the second step...

  11. Fractional Reserve Banking

    OpenAIRE

    Andreasen, Niels; Bjerregaard, Mads; Lund, Jonas; Olsen, Ove Bitsch; Rasmussen, Andreas Dalgas

    2012-01-01

    Projektet er bygget op omkring kritisk realisme, som er det gennemgående videnskabelige fundament til undersøgelsen af hvilke strukturelle grunde der er til finansiel ustabilitet i Danmark. Projektet går i dybden med Fractional Reserve Banking og incitamentsstrukturen i banksystemet. Vi bevæger os både på det makro- og mikroøkonomiske niveau i analysen. På makro niveau bruger vi den østrigske skole om konjunktur teori (The Positive Theory of the Cycle). På mikro niveau arbejder vi med princip...

  12. Fractional Reserve Banking

    OpenAIRE

    Andreasen, Niels; Bjerregaard, Mads; Lund, Jonas; Olsen, Ove Bitsch; Rasmussen, Andreas Dalgas

    2012-01-01

    Projektet er bygget op omkring kritisk realisme, som er det gennemgående videnskabelige fundament til undersøgelsen af hvilke strukturelle grunde der er til finansiel ustabilitet i Danmark. Projektet går i dybden med Fractional Reserve Banking og incitamentsstrukturen i banksystemet. Vi bevæger os både på det makro- og mikroøkonomiske niveau i analysen. På makro niveau bruger vi den østrigske skole om konjunktur teori (The Positive Theory of the Cycle). På mikro niveau arbejder vi med princip...

  13. Fractional Integral Inequalities via Hadamard’s Fractional Integral

    OpenAIRE

    2014-01-01

    We establish new fractional integral inequalities, via Hadamard’s fractional integral. Several new integral inequalities are obtained, including a Grüss type Hadamard fractional integral inequality, by using Young and weighted AM-GM inequalities. Many special cases are also discussed.

  14. Body Fractions: A Physical Approach to Fraction Learning

    Science.gov (United States)

    Mills, Judith

    2011-01-01

    Many students experience great difficulty understanding the meaning of fractions. For many students who have spent their early mathematics lessons focusing on counting (whole) numbers, recognising that there are many numbers between those whole numbers called fractional numbers, is quite revolutionary. The foundation of understanding fractions is…

  15. Cosmological Models with Fractional Derivatives and Fractional Action Functional

    Institute of Scientific and Technical Information of China (English)

    V.K. Shchigolev

    2011-01-01

    Cosmological models of a scalar field with dynamical equations containing fractional derivatives or derived from the Einstein-Hilbert action of fractional order, are constructed. A number of exact solutions to those equations of fractional cosmological models in both eases is given.

  16. The Geminga Fraction

    CERN Document Server

    Harding, A K; Gonthier, P L; Harding, Alice K.; Grenier, Isabelle A.; Gonthier, Peter L.

    2007-01-01

    Radio-quiet gamma-ray pulsars like Geminga may account for a number of the unidentified EGRET sources in the Galaxy. The number of Geminga-like pulsars is very sensitive to the geometry of both the gamma-ray and radio beams. Recent studies of the shape and polarization of pulse profiles of young radio pulsars have provided evidence that their radio emission originates in wide cone beams at altitudes that are a significant fraction (1 -10%) of their light cylinder radius. Such wide radio emission beams will be visible at a much larger range of observer angles than the narrow core components thought to originate at lower altitude. Using 3D geometrical modeling that includes relativistic effects from pulsar rotation, we study the visibility of such radio cone beams as well as that of the gamma-ray beams predicted by slot gap and outer gap models. From the results of this study one can obtain revised predictions for the fraction of Geminga-like, radio quiet pulsars present in the gamma-ray pulsar population.

  17. Identification of Prodigiosin-producing Serratia marcescens HFUT1301 Strain Isolated from Mandarin Fish Intestine%一株分离自鳜鱼肠道的粘质沙雷氏菌(Serratia marcescens)HFUT 1301的鉴定及灵菌红素的分析

    Institute of Scientific and Technical Information of China (English)

    张丹峰; 杨培周; 姜绍通

    2015-01-01

    灵菌红素是粘质沙雷氏菌(Serratia marcescens)产生的具有抗癌功效的一种色素.本研究从鳜鱼肠道中筛选出一株高产红色素的菌株,根据形态学特征、生理生化性质、16S rDNA对其进行鉴定,采用紫外可见光全波长扫描、LC-MS和FT-IR图谱鉴定该菌种产红色素的结构,研究表明:在基础培养基上菌落呈圆形、直径1-3 mm、中间红色不透明,呈隆起状、边缘整齐,16S rDNA片段大小为1445bp,与粘质沙雷氏菌同源性为99%,将该菌株命名为S.marcescens HFUT 1301;通过超声波辅助乙醇浸提及硅胶色谱分离纯化,获得纯度超过95%的红色素;在pH 3和pH 10的甲醇溶液中,该色素分别在535 nm和470 nm波长处存在明显吸收峰;LC-MS图谱主要离子峰为323.5486和324.8468;FT-IR图谱的主要吸收波数为3396 cm-1、2923 cm-1、2851 cm-1、1710 cm-1、1465cm-1和1164 cm-1.根据已有报道灵菌红素结构特征,推测该红色素为灵菌红素.在发酵培养基上灵菌红素产量达到3.22 g/L.

  18. Construction of a smart cDNA library of Asian yellow pond turtle stimulated with Serratia marcescens and identification of related genes%黏质沙雷氏菌诱导的黄喉拟水龟SMART cDNA文库构建及相关基因的鉴定

    Institute of Scientific and Technical Information of China (English)

    赵密; 朱新平; 史燕; 高明英

    2011-01-01

    以致病黏质沙雷氏菌人工感染的黄喉拟水龟肝组织为材料,应用SMART(switching mechanism at5'end of RNA transcript)技术,构建了黄喉拟水龟的全长cDNA文库.首先用SMARTTM PCR cDNA systhesis kit合成全长的双链cDNA,通过琼脂糖凝胶分级分离技术切除小片段的cDNA,将大于500 bp的cDNA连接到pGEM-T载体中,电转化到JM109感受态细胞.在构建好的文库中,经测定,文库约含有1.8×105个重组子,重组效率达90%,插入片段多在0.5~3.0 kb之间.对库中长度约为1 000 bp的80个基因进行了测序,结果显示大部分首次在龟类发现.测序鉴定的基因包括免疫相关基因9个、信号传导基因6个、催化酶类基因8个、糖代谢相关基因2个、转运相关基因1个、结构基因2个.%To understand anti-infectious response to bacteria in the Asian yellow pond turtle (Mauremys mutica), a full length cDNA library was constructed for it by SMART technique experimentally infected with Serratia marcescens. Firstly, the double-strand cDNA was synthesized using SMARTTM PCR cDNA systhesis kit. Second, the ds cDNA was separated into two parts based on the size distribution of amplified ds cDNA by agarose gel size fractionation. The part shorter than 500 bp was discarded and the other one longer than 500 bp was ligated to the pGEM-T vector. The ligation mixture was transformed into E. coli JM109 by electroporation. The cDNA library contained 1.8 × 105 independent clones with DNA inserts of 0. 5-3. 0 kb. The recombination rate was 90. 30%. We sequenced 80 cDNA clones about 1 kb and most of the genes were found the first time in reptiles. We classified these clones in functions with 9 in immunity, 6 in cell signaling, 8 in catalytic activity, 2 in sugar/glycolysis metabolism, 1 in transport metabolism, and 2 in cell structure. The successfully constructed cDNA library will be essential for rapid isolation of differentially expressed genes related to Serratia marcescens

  19. NESDIS VIIRS Green Vegetation Fraction

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains weekly Green Vegetation Fraction (GVF) derived from VIIRS. The Green Vegetation Fraction product is updated daily and is used as an input to...

  20. Advances in robust fractional control

    CERN Document Server

    Padula, Fabrizio

    2015-01-01

    This monograph presents design methodologies for (robust) fractional control systems. It shows the reader how to take advantage of the superior flexibility of fractional control systems compared with integer-order systems in achieving more challenging control requirements. There is a high degree of current interest in fractional systems and fractional control arising from both academia and industry and readers from both milieux are catered to in the text. Different design approaches having in common a trade-off between robustness and performance of the control system are considered explicitly. The text generalizes methodologies, techniques and theoretical results that have been successfully applied in classical (integer) control to the fractional case. The first part of Advances in Robust Fractional Control is the more industrially-oriented. It focuses on the design of fractional controllers for integer processes. In particular, it considers fractional-order proportional-integral-derivative controllers, becau...

  1. Fractional Reserve in Banking System

    OpenAIRE

    Valkonen, Maria

    2016-01-01

    This thesis is aimed to provide understanding of the role of the fractional reserve in the mod-ern banking system worldwide and particularly in Finland. The fractional reserve banking is used worldwide, but the benefits of this system are very disputable. On the one hand, experts say that the fractional reserve is a necessary instrument for the normal business and profit making. On the other hand, sceptics openly criticize the fractional reserve system and blame it for fiat money (money n...

  2. Fractional Reserve in Banking System

    OpenAIRE

    Valkonen, Maria

    2016-01-01

    This thesis is aimed to provide understanding of the role of the fractional reserve in the mod-ern banking system worldwide and particularly in Finland. The fractional reserve banking is used worldwide, but the benefits of this system are very disputable. On the one hand, experts say that the fractional reserve is a necessary instrument for the normal business and profit making. On the other hand, sceptics openly criticize the fractional reserve system and blame it for fiat money (money n...

  3. Experimental observation of fractional echoes

    Science.gov (United States)

    Karras, G.; Hertz, E.; Billard, F.; Lavorel, B.; Siour, G.; Hartmann, J.-M.; Faucher, O.; Gershnabel, Erez; Prior, Yehiam; Averbukh, Ilya Sh.

    2016-09-01

    We report the observation of fractional echoes in a double-pulse excited nonlinear system. Unlike standard echoes, which appear periodically at delays which are integer multiples of the delay between the two exciting pulses, the fractional echoes appear at rational fractions of this delay. We discuss the mechanism leading to this phenomenon, and provide experimental demonstration of fractional echoes by measuring third harmonic generation in a thermal gas of CO2 molecules excited by a pair of femtosecond laser pulses.

  4. Fractional Hopfield Neural Networks: Fractional Dynamic Associative Recurrent Neural Networks.

    Science.gov (United States)

    Pu, Yi-Fei; Yi, Zhang; Zhou, Ji-Liu

    2016-07-14

    This paper mainly discusses a novel conceptual framework: fractional Hopfield neural networks (FHNN). As is commonly known, fractional calculus has been incorporated into artificial neural networks, mainly because of its long-term memory and nonlocality. Some researchers have made interesting attempts at fractional neural networks and gained competitive advantages over integer-order neural networks. Therefore, it is naturally makes one ponder how to generalize the first-order Hopfield neural networks to the fractional-order ones, and how to implement FHNN by means of fractional calculus. We propose to introduce a novel mathematical method: fractional calculus to implement FHNN. First, we implement fractor in the form of an analog circuit. Second, we implement FHNN by utilizing fractor and the fractional steepest descent approach, construct its Lyapunov function, and further analyze its attractors. Third, we perform experiments to analyze the stability and convergence of FHNN, and further discuss its applications to the defense against chip cloning attacks for anticounterfeiting. The main contribution of our work is to propose FHNN in the form of an analog circuit by utilizing a fractor and the fractional steepest descent approach, construct its Lyapunov function, prove its Lyapunov stability, analyze its attractors, and apply FHNN to the defense against chip cloning attacks for anticounterfeiting. A significant advantage of FHNN is that its attractors essentially relate to the neuron's fractional order. FHNN possesses the fractional-order-stability and fractional-order-sensitivity characteristics.

  5. Nonholonomic constraints with fractional derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, Vasily E [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119992 (Russian Federation); Zaslavsky, George M [Courant Institute of Mathematical Sciences, New York University, 251 Mercer St, New York, NY 10012 (United States)

    2006-08-04

    We consider the fractional generalization of nonholonomic constraints defined by equations with fractional derivatives and provide some examples. The corresponding equations of motion are derived using variational principle. We prove that fractional constraints can be used to describe the evolution of dynamical systems in which some coordinates and velocities are related to velocities through a power-law memory function.

  6. How Weird Are Weird Fractions?

    Science.gov (United States)

    Stuffelbeam, Ryan

    2013-01-01

    A positive rational is a weird fraction if its value is unchanged by an illegitimate, digit-based reduction. In this article, we prove that each weird fraction is uniquely weird and initiate a discussion of the prevalence of weird fractions.

  7. Nonhomogeneous fractional Poisson processes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaotian [School of Management, Tianjin University, Tianjin 300072 (China)]. E-mail: swa001@126.com; Zhang Shiying [School of Management, Tianjin University, Tianjin 300072 (China); Fan Shen [Computer and Information School, Zhejiang Wanli University, Ningbo 315100 (China)

    2007-01-15

    In this paper, we propose a class of non-Gaussian stationary increment processes, named nonhomogeneous fractional Poisson processes W{sub H}{sup (j)}(t), which permit the study of the effects of long-range dependance in a large number of fields including quantum physics and finance. The processes W{sub H}{sup (j)}(t) are self-similar in a wide sense, exhibit more fatter tail than Gaussian processes, and converge to the Gaussian processes in distribution in some cases. In addition, we also show that the intensity function {lambda}(t) strongly influences the existence of the highest finite moment of W{sub H}{sup (j)}(t) and the behaviour of the tail probability of W{sub H}{sup (j)}(t)

  8. Membrane Assisted Enzyme Fractionation

    DEFF Research Database (Denmark)

    Yuan, Linfeng

    . In this thesis, separations using crossflow elecro-membrane filtration (EMF) of amino acids, bovine serum albumin (BSA) and industrial enzymes from Novozymes were performed. The main objective of this study was to investigate the technological feasibility of EMF in the application of industrial enzyme...... fractionation, such as removal of a side activity from the main enzyme activity. As a proof-of-concept, amino acids were used as model solution to test the feasibility of EMF in the application of amphoteric molecule separation. A single amino acid was used to illustrate the effect of an electric field...... on the separation performance were very small in the investigated range. The mass transport of each enzyme can be well explained by the Extended-Nernst-Planck equation. Better separation was observed at lower feed concentration, higher solution pH in the investigated range and with a polysulfone (PS) MF membrane...

  9. Membrane Assisted Enzyme Fractionation

    DEFF Research Database (Denmark)

    Yuan, Linfeng

    . In this thesis, separations using crossflow elecro-membrane filtration (EMF) of amino acids, bovine serum albumin (BSA) and industrial enzymes from Novozymes were performed. The main objective of this study was to investigate the technological feasibility of EMF in the application of industrial enzyme...... fractionation, such as removal of a side activity from the main enzyme activity. As a proof-of-concept, amino acids were used as model solution to test the feasibility of EMF in the application of amphoteric molecule separation. A single amino acid was used to illustrate the effect of an electric field...... on the separation performance were very small in the investigated range. The mass transport of each enzyme can be well explained by the Extended-Nernst-Planck equation. Better separation was observed at lower feed concentration, higher solution pH in the investigated range and with a polysulfone (PS) MF membrane...

  10. Fractional Chemotaxis Diffusion Equations

    CERN Document Server

    Langlands, T A M

    2010-01-01

    We introduce mesoscopic and macroscopic model equations of chemotaxis with anomalous subdiffusion for modelling chemically directed transport of biological organisms in changing chemical environments with diffusion hindered by traps or macro-molecular crowding. The mesoscopic models are formulated using Continuous Time Random Walk master equations and the macroscopic models are formulated with fractional order differential equations. Different models are proposed depending on the timing of the chemotactic forcing. Generalizations of the models to include linear reaction dynamics are also derived. Finally a Monte Carlo method for simulating anomalous subdiffusion with chemotaxis is introduced and simulation results are compared with numerical solutions of the model equations. The model equations developed here could be used to replace Keller-Segel type equations in biological systems with transport hindered by traps, macro-molecular crowding or other obstacles.

  11. Multifarious beneficial traits and plant growth promoting potential of Serratia marcescens KiSII and Enterobacter sp. RNF 267 isolated from the rhizosphere of coconut palms (Cocos nucifera L.).

    Science.gov (United States)

    George, Priya; Gupta, Alka; Gopal, Murali; Thomas, Litty; Thomas, George V

    2013-01-01

    Two plant growth promoting bacteria designated as KiSII and RNF 267 isolated from the rhizosphere of coconut palms were identified as Serratia marcescens and Enterobacter sp. based on their phenotypic features, BIOLOG studies and 16S rRNA gene sequence analysis. Both bacteria exhibited phosphate solubilization, ammonification, and production of indole acetic acid, β-1, 3 glucanase activities and 1-aminocyclopropane-1-carboxylate-deaminase activity. They could also tolerate a range of pH conditions, low temperature and salinity (NaCl). In addition, S. marcescens KiSII exhibited N- fixation potential, chitinase activity, siderophore production and antibiotics production. Seed bacterization with these bacteria increased the growth parameters of test plants such as paddy and cowpea over uninoculated control in green house assay. In coconut seedlings, significant increase in growth and nutrient uptake accompanied with higher populations of plant beneficial microorganisms in their rhizospheres were recorded on inoculation with both the PGPRs. The present study clearly revealed that PGPRs can aid in production of healthy and vigorous seedlings of coconut palm which are hardy perennial crops. They offer a scope to be developed into novel PGPR based bioinoculants for production of elite seedlings that can benefit the coconut farming community and the coconut based ecology.

  12. Current status of prevalence of nosocomial infections caused by Serratia marcescens and analysis of drug resistance%褪色沙雷菌医院感染现状及耐药性分析

    Institute of Scientific and Technical Information of China (English)

    方叶青; 胡庆丰; 魏取好; 吕火烊

    2015-01-01

    OBJECTIVE To understand the clinical characteristics of Serratia marcescens infections and observe the current status of drug resistance so as to provide guidance for clinical treatment and control of nosocomial infections .METHODS From 2008 to 2012 ,the distribution of 300 clinical S .marcescens isolates was retrospective‐ly analyzed ,the change of the drug resistance spectrum was observed ,and the drug resistance of the strains was compared between the ICU wards and the non‐ICU wards .RESULTS During the five years ,the clinical isolation rate of S .marcescens causing nosocomial infections was increased year by year ,increasing from 0 .8% in 2008 to 5 .3% in 2012 .Among the isolated S .marcescens strains ,44 .7% were isolated from the ICU1 ,17 .3% from the surgery department ,16 .0% from the internal medicine department ,7 .7% from the respiratory department ;the sputum was the predominant specimen source ,accounting for 85 .6% .The drug resistance of the S .marcescens to cefoperazone‐sulbactam ,ceftazidime , ceftriaxone , imipenem , and gentamycin showed an upward trend ( P<0 .05);by 2012 ,the drug resistance rate to cefoperazone‐sulbactam reached 24 .7% ,ceftriaxone 59 .2% ,imipen‐em 24 .3% ,gentamycin 24 .9% ;the S .marcescens strains were highly susceptible to amikacin ,tobramycin ,and levofloxacin ,with the drug resistance rates of 1 .2% ,3 .6% ,and 5 .9% ,respectively ;the drug resistance rates of the S .marcescens strains isolated from the ICUs to compound preparation ,cephalosporins ,and carbapenems were significantly higher than those of the strains isolated from the non‐ICUs ,while the drug susceptibility rate to ami‐noglycosides and quinolones were higher in the ICUs than in the non‐ICUs .CONCLUSION The incidence of the S . marcescens infections shows an upward trend .It is necessary for the hospital to reasonably use antibiotics on the basis of the results of drug susceptibility testing so as to prevent the emergence of drug

  13. 粘质沙雷菌整合子检测及其与耐药表型的相关性分析%Serratia marcescens integron test and Associated analysis with drug resistance phenotype

    Institute of Scientific and Technical Information of China (English)

    苏维奇; 朱元祺; 李莉; 毕春霞; 闫志勇; 邓乃梅

    2015-01-01

    Objective Understanding of the carrying situation in the region of Serratia marcescens isolates Ⅰ,Ⅱ,Ⅲintegron,To explore the relationship between integrons and drug resistance phenotype.Methods Clinical isolates col-lected by VITEK-2 Compact analysis system for identification of 287 strains of Serratia marcescens.Prepared to boil PCR amplification of bacterial DNA as a template,using the polymerase chain reaction (PCR)testing of classⅠ,Ⅱ,Ⅲintegron.Analysis and comparison the differences of integron positive strains and negative strains in drug sensitive test. Results In 287 strains of Serratia marcescens,262 strains of bacteria detected integron,the detection rate was 91.3%, 3 strains of bacteria detected class Ⅲ integron,II integron were not detected.The drug sensitivity results showed,the classⅠ integron positive strains resistant to ciprofloxacin and cefotaxime were higher than that of Ⅰintegron negative strains (P0.05).Conclusion Ⅰ integron prevalent in Serratia marcescens,class Ⅰ integron and mul-tidrug-resistant Serratia marcescens is no significant correlation.%目的:了解本地区粘质沙雷菌临床分离株Ⅰ、Ⅱ、Ⅲ类整合子的携带情况,探讨整合子与其耐药表型的相关性。方法收集临床分离的经 VITEK-2 Compact 细菌分析系统鉴定的粘质沙雷菌287株,以煮沸法制备细菌DNA作为PCR扩增模板,采用聚合酶链反应(PCR)检测菌株的第Ⅰ、Ⅱ、Ⅲ类整合子,分析比较整合子阳性菌株与阴性菌株的药敏试验结果差异。结果在287株粘质沙雷菌中,有262株细菌检出Ⅰ类整合子,检出率为91.3%,3株细菌检出Ⅲ类整合子,未检出Ⅱ类整合子。药敏结果显示,第Ⅰ类整合子阳性菌株对环丙沙星和头孢噻肟的耐药率高于Ⅰ类整合子阴性菌株(P均<0.05),对其他抗菌药物的耐药性,Ⅰ类整合子阳性菌株和阴性菌株间差异无统计学意义(P均>0.05)。

  14. 空间环境诱导褪色沙雷菌LCT-SM166的蛋白质组学分析%Proteomics of space serratia marcescens LCT-SM166 strain

    Institute of Scientific and Technical Information of China (English)

    王雅娟; 姜学革; 刘岩; 陈振鸿; 王立; 刘长庭; 刘进文; 方向群; 李天志; 王俊锋; 郭英华; 徐国纲; 常德; 苏龙翔

    2013-01-01

    Objective To analyze and identify the proteins with different expressions in serratia marcescens loaded in Shenzhou 8 spacecraft. Methods The serratia marcescens strain LCT-SM166 loaded in Shenzhou 8 spacecraft and ground control strain LCT-SM213 were isolated and their 16sRN was identified by isobaric tags for relative and absolute quantitation (iTRAQ). The proteins of serratia marcescens LCT-SM166 and LCT-SM213 strains were detected by mass spectrometry and their differential expression was analyzed. Results Among the 111 differentially expressed proteins in the 1 713 possible proteins identified in this study, the expression was up-regulated in 20 and down-regulated in 91. Gene ontology (GO) enrichment analysis showed that the majority of differentially expressed proteins were related to bacterial metabolism. Conclusion Space environment can affect the protein expressions of serratia marcescens. The differentially expressed proteins mainly participate in the bacterial metabolic process. Proteomic analysis of space serratia marcescens mutants can lay a foundation for further transomics analysis.%  目的分析和鉴定神舟八号飞船搭载褪色沙雷菌的差异表达蛋白质。方法对神州八号飞船搭载的褪色沙雷菌LCT-SM166及地面对照组LCT-SM213进行分离并进行16sRNA鉴定,采用同重同位素相对与绝对定量(isobaric tags for relative and absolute quantitation,iTRAQ)方法对褪色沙雷菌LCT-SM166和LCT-SM213进行蛋白质组质谱检测,分析两株菌的差异表达蛋白。结果共鉴定到1713个蛋白质,LCT-SM166与LCT-SM213的差异蛋白组学分析发现了111个蛋白质表达的改变,其中29个蛋白表达上调,91个蛋白表达下调。基因本体论(gene ontology,GO)功能富集分析显示大多数差异蛋白质主要与能量代谢有关。结论空间环境可影响褪色沙雷菌大量蛋白质的表达,差异表达蛋白主要分布在代谢相关过程。空间诱变菌

  15. 黏质沙雷菌中AmpC酶的检测及药敏率分析%Antimicrobial resistance of AmpC-producing serratia marcescens in Anhui

    Institute of Scientific and Technical Information of China (English)

    杨海飞; 程君; 胡立芬; 刘艳艳; 潘亚超; 朱玉林; 李家斌

    2012-01-01

    Objective To investigate the resistance of AmpC - producing Serratia marcescens for providing the scientific evidence in clinical diagnosis and treatment. Methods Potential AmpC - producing strains were detected by the cefoxitin disk diffusion method as described by CLSI 2010. Three - dimensional test was adopted for confirming AmpC - producing strains. The MICs of Serratia marcescens were determined by broth microdilution method. The results were judged according to the criteria recommended by CLSI 2010. Results The majority of Serratia marcescens were isolated from the specimen of sputum, accounting for 59. 6% . The bacteria were mostly detected in Respiratory department, followed by Intensive Care Unit, Gerontology Department. 41 of 104 isolates were identified as resistant to cefoxitin, accounting for 39. 4%. 8 strains ( 7. 7% ) produced AmpC β - lactamases. The antimicrobial susceptibility test showed that all strains were sensitive to imipenem and meropenem. The rates of resistance to cefepime, levofloxacin and gatifloxacin remained relatively unchanged between AmpC - producing strains and non - AmpC - producing strains. The resistant rates to other antimicrobial agents were significantly statistical difference ( P <0. 05 ) between the AmpC - producers and the non - AmpC - producers. Conclusion It showed that the production of AmpC β -lactamases in Serratia marcescens confers a high level of resistance to most kinds of antimicrobial agents. Carbapenems, fluoro-quinolones, and fourth generation cephalosporins should be selected in empirical therapy of serious infections caused by AmpC - producing Serratia marcescens.%目的 了解安徽省临床分离的104株黏质沙雷菌中AmpC酶的产生情况及其对常用抗菌药物的耐药特征,以指导临床合理用药.方法 采用头孢西丁纸片扩散法筛选疑产AmpC酶阳性菌株,并用酶粗提物进行三维试验确证产AmpC酶菌株.药敏试验采用琼脂稀释法,依据CLSI 2010年推荐的

  16. Fractional Calculus: Integral and Differential Equations of Fractional Order

    CERN Document Server

    Gorenflo, Rudolf

    2008-01-01

    We introduce the linear operators of fractional integration and fractional differentiation in the framework of the Riemann-Liouville fractional calculus. Particular attention is devoted to the technique of Laplace transforms for treating these operators in a way accessible to applied scientists, avoiding unproductive generalities and excessive mathematical rigor. By applying this technique we shall derive the analytical solutions of the most simple linear integral and differential equations of fractional order. We show the fundamental role of the Mittag-Leffler function, whose properties are reported in an ad hoc Appendix. The topics discussed here will be: (a) essentials of Riemann-Liouville fractional calculus with basic formulas of Laplace transforms, (b) Abel type integral equations of first and second kind, (c) relaxation and oscillation type differential equations of fractional order.

  17. An improved fractional divider for fractional-N frequency synthesizers

    Science.gov (United States)

    Zhang, Wei; Liu, Yang; Zhou, Yongqi

    2009-07-01

    This paper presents an improved fractional divider used in 1.8~2GHz fractional-N frequency synthesizers. A new clock setting for delta-sigma modulator (DSM) is proposed to prevent the potential problems of traditional fractional dividers: the DSM output would be wrongly loaded and the action of DSM circuit may affect the phase-detection of phase-frequency-detector (PFD). Simulation result shows the effectiveness of this improvement.

  18. QM/MM free-energy simulations of reaction in Serratia marcescens Chitinase B reveal the protonation state of Asp142 and the critical role of Tyr214.

    Science.gov (United States)

    Jitonnom, Jitrayut; Limb, Michael A L; Mulholland, Adrian J

    2014-05-01

    Serratia marcescens Chitinase B (ChiB), belonging to the glycosidase family 18 (GH18), catalyzes the hydrolysis of β-1,4-glycosidic bond, with retention of configuration, via an unusual substrate-assisted mechanism, in which the substrate itself acts as an intramolecular nucleophile. Here, both elementary steps (glycosylation and deglycosylation) of the ChiB-catalyzed reaction are investigated by means of combined quantum mechanics/molecular mechanics (QM/MM) umbrella sampling molecular dynamics (MD) simulations at the SCC-DFTB/CHARMM22 level of theory. We examine the influence of the Asp142 protonation state on the reaction and the role that this residue performs in the reaction. Our simulations show that reaction with a neutral Asp142 is preferred and demonstrate that this residue provides electrostatic stabilization of the oxazolinium ion intermediate formed in the reaction. Insight into the conformational itinerary ((1,4)B↔(4)H5↔(4)C1) adopted by the substrate (bound in subsite -1) along the preferred reaction pathway is also provided by the simulations. The relative energies of the stationary points found along the reaction pathway calculated with SCC-DFTB and B3LYP were compared. The results suggest that SCC-DFTB is an accurate method for estimating the relative barriers for both steps of the reaction; however, it was found to overestimate the relative energy of an intermediate formed in the reaction when compared with the higher level of theory. Glycosylation is suggested to be a rate-determining step in the reaction with calculated overall reaction free-energy barrier of 20.5 kcal/mol, in a reasonable agreement with the 16.1 kcal/mol barrier derived from the experiment. The role of Tyr214 in catalysis was also investigated with the results, indicating that the residue plays a critical role in the deglycosylation step of the reaction. Simulations of the enzyme-product complex were also performed with an unbinding event suggested to have been observed

  19. Incompressible Stars and Fractional Derivatives

    CERN Document Server

    Bayin, S S

    2014-01-01

    Fractional calculus is an effective tool in incorporating the effects of non-locality and memory into physical models. In this regard, successful applications exist rang- ing from signal processing to anomalous diffusion and quantum mechanics. In this paper we investigate the fractional versions of the stellar structure equations for non radiating spherical objects. Using incompressible fluids as a comparison, we develop models for constant density Newtonian objects with fractional mass distributions or stress conditions. To better understand the fractional effects, we discuss effective values for the density, gravitational field and equation of state. The fractional ob- jects are smaller and less massive than integer models. The fractional parameters are related to a polytropic index for the models considered.

  20. Proton Fraction in Neutron Stars

    Institute of Scientific and Technical Information of China (English)

    张丰收; 陈列文

    2001-01-01

    The proton fraction in β-stable neutron stars is investigated within the framework of the Skyrme-Hartree-Fock theory using the extended Skyrme effective interaction for the first time. The calculated results show that the proton fraction disappears at high density, which implies that the pure neutron matter may exist in the interior of neutron stars. The incompressibility of the nuclear equation-of-state is shown to be more important to determine the proton fraction. Meanwhile, it is indicated that the addition of muons in neutron stars will change the proton fraction. It is also found that the higher-order terms of the nuclear symmetry energy have obvious effects on the proton fraction and the parabolic law of the nuclear symmetry energy is not enough to determine the proton fraction.

  1. Accessible solitons of fractional dimension

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Wei-Ping, E-mail: zhongwp6@126.com [Department of Electronic and Information Engineering, Shunde Polytechnic, Guangdong Province, Shunde 528300 (China); Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Belić, Milivoj [Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Zhang, Yiqi [Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China)

    2016-05-15

    We demonstrate that accessible solitons described by an extended Schrödinger equation with the Laplacian of fractional dimension can exist in strongly nonlocal nonlinear media. The soliton solutions of the model are constructed by two special functions, the associated Legendre polynomials and the Laguerre polynomials in the fraction-dimensional space. Our results show that these fractional accessible solitons form a soliton family which includes crescent solitons, and asymmetric single-layer and multi-layer necklace solitons. -- Highlights: •Analytic solutions of a fractional Schrödinger equation are obtained. •The solutions are produced by means of self-similar method applied to the fractional Schrödinger equation with parabolic potential. •The fractional accessible solitons form crescent, asymmetric single-layer and multilayer necklace profiles. •The model applies to the propagation of optical pulses in strongly nonlocal nonlinear media.

  2. Number line representations of fractions

    OpenAIRE

    Behr, Merlyn J.; Bright, George W.; Wachsmuth, Ipke; Wagner, Sigrid

    1982-01-01

    The study explored students' interpretations of representations of fractions on number lines and the effect of instruction on those interpretations. Subjects were five fourth-graders, and instruction was a four-day unit on the use of number lines. A 16-item, multiple-choice pre- and posttest was used along with videotaped interviews. Performance improved except when students had to associate a reduced fraction symbol with an equivalent, unreduced fraction representation on a number line. The ...

  3. 肿瘤医院粘质沙雷菌所致院内下呼吸道感染情况分析%Analysis of Serratia marcescens causing hospital-acquired lower respiratory tract infection in cancer hospital

    Institute of Scientific and Technical Information of China (English)

    王久惠; 叶波; 贾红; 李舸; 魏晋勇

    2011-01-01

    目的 了解肿瘤医院内粘质沙雷菌所致院内下呼吸道感染的临床特点和对常用杭菌药物的耐药情况,为临床治疗院内下呼吸道感染提供依据.方法 对我院2007年1月~2009年12月116例粘质沙雷菌所致院内下呼吸道感染的临床特点以及痰中分离的138株粘质沙雷菌耐药性进行分析.结果 肿瘤医院粘质沙雷菌所致院内下呼吸道感染患者中原发病以食管癌、肺癌术后、放化疗后为主(肺癌占45%,食管癌占27%).粘质沙雷菌对目前常用抗菌药物有不同程度耐药,对阿莫西林、替卡西林、头孢西丁、头孢呋辛耐药率较高,均>50%,对亚胺培南、哌拉西林/他唑巴坦、头孢他啶、头孢哌酮/舒巴坦、头孢吡肟、阿米卡星、左氧氟沙星敏感率均>80%,但大多数耐药率有逐年上升的趋势.结论 肿瘤医院内对于经手术或多程放化疗后的肿瘤患者尤其是食管癌、肺癌要考虑可能并发粘质沙雷菌院内感染的发生,应及时进行微生物学检查,尽早依据药敏选用抗菌药物.粘质沙雷菌对半合成青霉素、二代头孢菌素表现很高的耐药性,对三代头孢菌素也表现不同程度的耐药,临床医生应重视.%Objective To study the clinical charateristics of the serratia marcescens causing hospital-acquired lower respiratory- tract infection in cancer hospital and its drug resistance to commonly used antibiotics in order to apply basis for the treatment of the hospital-acquired lower respiratory- tract infection. Methods Clinical charateristics of 116 cases of patients with serratia marcescens causing hospital-acquired lower respiratory tract infection from Jan. 2007 to Dec. 2009 as well as the drug-resistance of 138 strains of serratia marcescens seperated from sputum were analyzed in this study. Results The primary diseases of the serratia marcescens causing hospital-acquired lower respiratory-tract infection in cancer hospital included easophagus

  4. 安徽省104株黏质沙雷菌的分布及耐药性监测%Distribution and resistance surveillance of 104 clinical strains of Serratia marcescens in Anhui Province

    Institute of Scientific and Technical Information of China (English)

    程君; 杨海飞; 朱玉林; 胡立芬; 潘亚超; 刘艳艳; 叶英; 李家斌

    2012-01-01

    Objective To analyze the clinical distribution and antimicrobial resistance profile of Serratia marcescens (S. marcescens), and to provide the scientific evidence supporting clinical diagnosis and treatment.Methods The antimicrobial susceptibility test was performed in 104 strains of S. marcescens by agar dilution method. The results were judged according to the criteria recommended by Clinical and Laboratory Standards Institute (CLSI) 2010.The data were analyzed by chi square test. Results The majority of S. marcescens were isolated from sputum specimens,accounting for 59.6% (62/104). The bacteria were most frequently isolated from department of respiratory (33.7%,35/104),followed by intensive care unit (23.1%,24/104),department of gerontology (16.3%, 17/104). The results of antimicrobial susceptibility test showed that the resistance rates of S.marcescens against ampicillin,gentamicin and cephazolin were high,which were 90.4%,86.5% and 79.8%,respectively; those against the 3rd generation of cephalosporins were 24.0%-43.3%. No imipenem and meropenem resistant strains were identified. Compared with cefoxitin-resistant strains,the resistance rates of non-cefoxitin resistant strains against piperacillin (82.9% vs 28.6%),ceftazidime (63.4% vs 9.5%),aztreonam (68.3% vs 9.5%),amikacin (68.3% vs 20.6%),ciprofloxacin (48.8% vs 19.1%) and chloramphenicol (90.3% vs 58.7%) were all lower (all P < 0.05 ). Conclusions S. marcescens is one of the most common conditional pathogenic bacteria leading to nosocomial infections,which is resistant to many kinds of antimicrobial agents.The surveillance of antimicrobial resistance in S. marcescens should be strengthened for purpose of preventing the transmission of multidrug resistant strains.%目的 探讨黏质沙雷菌感染的临床分布及耐药特点,为临床诊断和治疗提供依据.方法 104株黏质沙雷菌药物敏感试验采用琼脂稀释法,结果依据临

  5. Comment on "Fractional quantum mechanics" and "Fractional Schroedinger equation"

    CERN Document Server

    Wei, Yuchuan

    2016-01-01

    In this comment, we point out some shortcomings in two papers "Fractional quantum mechanics" [Phys. Rev. E 62, 3135 (2000)] and "Fractional Schroedinger equation" [Phys. Rev. E 66, 056108 (2002)]. We prove that the fractional uncertainty relation does not hold generally. The probability continuity equation in fractional quantum mechanics has a missing source term, which leads to particle teleportation, i.e., a particle can teleport from one place to another. Since the relativistic kinetic energy can be viewed as an approximate realization of the fractional kinetic energy, the particle teleportation should be an observable relativistic effect in quantum mechanics. With the help of this concept, superconductivity could be viewed as the teleportation of electrons from one side of a superconductor to another and superfluidity could be viewed as the teleportation of helium atoms from one end of a capillary tube to the other. We also point out how to teleport a particle to a destination.

  6. COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS

    Energy Technology Data Exchange (ETDEWEB)

    S.O. Bader

    1999-10-18

    The purpose of this design analysis is to specify and document the total and respirable fractions for radioactive materials that are released from an accident event at the Monitored Geologic Repository (MGR) involving commercial spent nuclear fuel (CSNF) in a dry environment. The total and respirable release fractions will be used to support the preclosure licensing basis for the MGR. The total release fraction is defined as the fraction of total CSNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. The radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses. This subset of the total release fraction is referred to as the respirable release fraction. Potential accidents may involve waste forms that are characterized as either bare (unconfined) fuel assemblies or confined fuel assemblies. The confined CSNF assemblies at the MGR are contained in shipping casks, canisters, or disposal containers (waste packages). In contrast to the bare fuel assemblies, the container that confines the fuel assemblies has the potential of providing an additional barrier for diminishing the total release fraction should the fuel rod cladding breach during an accident. However, this analysis will not take credit for this additional bamer and will establish only the total release fractions for bare unconfined CSNF assemblies, which may however be

  7. 粘质沙雷氏菌α-乙酰乳酸脱羧酶基因的体外表达%Expression of Serratia marcescens α-Acetolactate Decarboxylase Gene in Escherichia coli and Pichia pastoris

    Institute of Scientific and Technical Information of China (English)

    王亚平; 周荣华; 饶犇; 马立新

    2013-01-01

    根据GenBank中α-乙酰乳酸脱羧酶的基因序列(slaA)设计引物,以粘质沙雷氏菌(Serratia marcescens)HU1基因组DNA为模板通过PCR扩增得到了目标基因,全长为780 bp.将该基因分别连接到大肠杆菌表达载体pET30a和毕赤酵母表达栽体pPICZαA上,构建表达质粒pET30a-slaA和pPICZαA-slaA,并在对应的宿主中进行了表达.结果表明,大肠杆菌和毕赤酵母的表达产物的最适温度和pH均分别为40℃和7,两者在不同pH下的稳定性也相似,只不过毕赤酵母的表达产物的热稳定性要略强于大肠杆菌的表达产物.%Serratia marcescens α-acetolactate decarboxylase gene in Escherichia coli and Pichia pastoris,repectively.Primers of α-acetolactate decarboxylase gene (slaA) were designed according to the gene sequence in GeneBank; and target gene was obtained by PCR amplification using S.marcescens MG1 genomic DNA as template,which was 780 bp.Then slaA gene was inserted into pET-30a,expression vector of E.coli,and pPICZαA,expression vector of P.pastoris,resulting in plasmids pET30a-slaA and pPICZoA-slaA.The two expression vectors were introduced into the corresponding hosts and the gene was successfully expressed.The results showed that the optimum temperature and pH of the enzyme produced by E.coli and P.pastoris were both about 40 ℃ and 7,respectively.The stability of the enzyme at different pH from E.coli and P.pastoris was also similar.However,the thermal stability of the enzyme produced by P.pastoris was slightly stronger than that from E.coii.

  8. Screening of the Cultivation Medium of Prodigiosin Production from Serratia marcescens%粘质沙雷氏菌产灵菌红素培养基的筛选

    Institute of Scientific and Technical Information of China (English)

    黄小龙; 黄东益; 周双清; 吴繁花; 陶思宇

    2009-01-01

    目的:确定菌株S418产生灵菌红素的最优培养基配方及其的分类地位.方法:以花生粉为基础培养基,通过单因素试验和四因素三水平正交试验筛选出了菌株S418产灵菌红素的最佳培养基配方;根据该菌株的16S rRNA基因序列系统发育树分析初步确定了菌株S418的分类地位.结果:培养基最优配方为:花生粉2%,花生油0.5%,L-脯氨酸1%,硫酸镁0.025%.在28℃、pH7.5、250r/min振荡培养24h,灵菌红素产量达67.92mg/L.菌株S418初步鉴定为粘质沙雷氏菌(Serratia marcescens S418).结论:花生粉培养基是一种适合粘质沙雷氏菌产灵菌红素的优良培养基.%Objective:To determine optimal culture medium and taxonomic status of strain S418 producing prodigiosin.Method: In the base of preliminary determination that peanut powder was the basic medium for fermentable cultivation,the optimal submerged fermentation medium of prodigiosin production for the strain S418 were investigated by single factor test and L_9(3_4) orthogonal test.The strain S418 was identified by 16S ribosomal RNA gene sequences analysis.Result:It showed that the optimal culture was: Peanut powder 2%,peanut oil 0.5%,L-proline 1%,MgSO_4 0.025%.Under fermented condition: culture temperature 28℃,rotation speed 250r/min and fermentation time 24h,the yield of prodigiosin was 67.92mg/L.The strain S418 were preliminarily identified to Serratia marcescens S418.Conclusion: peanut powder broth was a optimal culture medium for prodigiosin production by Serratia marcescens.

  9. Deterministic ratchets for suspension fractionation

    NARCIS (Netherlands)

    Kulrattanarak, T.

    2010-01-01

    Driven by the current insights in sustainability and technological development in biorefining natural renewable resources, the food industry has taken an interest in fractionation of agrofood materials, like milk and cereal crops. The purpose of fractionation is to split the raw material in sever

  10. Financial Planning with Fractional Goals

    NARCIS (Netherlands)

    M.H. Goedhart; J. Spronk (Jaap)

    1995-01-01

    textabstractWhen solving financial planning problems with multiple goals by means of multiple objective programming, the presence of fractional goals leads to technical difficulties. In this paper we present a straightforward interactive approach for solving such linear fractional programs with mult

  11. Financial Planning with Fractional Goals

    OpenAIRE

    Goedhart, M.H.; Spronk, Jaap

    1995-01-01

    textabstractWhen solving financial planning problems with multiple goals by means of multiple objective programming, the presence of fractional goals leads to technical difficulties. In this paper we present a straightforward interactive approach for solving such linear fractional programs with multiple goal variables. The approach is illustrated by means of an example in financial planning.

  12. Approximations of fractional Brownian motion

    CERN Document Server

    Li, Yuqiang; 10.3150/10-BEJ319

    2012-01-01

    Approximations of fractional Brownian motion using Poisson processes whose parameter sets have the same dimensions as the approximated processes have been studied in the literature. In this paper, a special approximation to the one-parameter fractional Brownian motion is constructed using a two-parameter Poisson process. The proof involves the tightness and identification of finite-dimensional distributions.

  13. Investigations on Multiplication of Fractions.

    Science.gov (United States)

    Sai, Khoo Phon; Inder, Walter R. D.

    1984-01-01

    Three different models with continuous materials, discontinuous materials, and number lines were used to study the operation concept in six investigations on multiplication with fractions with pupils aged 11-12 in a Penang International School. All approaches could be understood by pupils, but they preferred the area and fractional models. (MNS)

  14. Understanding Magnitudes to Understand Fractions

    Science.gov (United States)

    Gabriel, Florence

    2016-01-01

    Fractions are known to be difficult to learn and difficult to teach, yet they are vital for students to have access to further mathematical concepts. This article uses evidence to support teachers employing teaching methods that focus on the conceptual understanding of the magnitude of fractions.

  15. Ejection Fraction Heart Failure Measurement

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More Ejection Fraction Heart Failure Measurement Updated:Feb 15,2017 The ejection fraction ( ... failure This content was last reviewed April 2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  16. Unwrapping Students' Ideas about Fractions

    Science.gov (United States)

    Lewis, Rebecca M.; Gibbons, Lynsey K.; Kazemi, Elham; Lind, Teresa

    2015-01-01

    Supporting students to develop an understanding of the meaning of fractions is an important goal of elementary school mathematics. This involves developing partitioning strategies, creating representations, naming fractional quantities, and using symbolic notation. This article describes how teachers can use a formative assessment problem to…

  17. Rational Exponentials and Continued Fractions

    Science.gov (United States)

    Denny, J. K.

    2012-01-01

    Using continued fraction expansions, we can approximate constants, such as pi and e, using an appropriate integer n raised to the power x[superscript 1/x], x a suitable rational. We review continued fractions and give an algorithm for producing these approximations.

  18. Wavelet-fractional Fourier transforms

    Institute of Scientific and Technical Information of China (English)

    Yuan Lin

    2008-01-01

    This paper extends the definition of fractional Fourier transform (FRFT) proposed by Namias V by using other orthonormal bases for L2 (R) instead of Hermite-Ganssian functions.The new orthonormal basis is gained indirectly from multiresolution analysis and orthonormal wavelets. The so defined FRFT is called wavelets-fractional Fourier transform.

  19. 菌株Serratia marcescens SYBC08产过氧化氢酶液态发酵工艺的优化及酶性质研究%Optimization of Fermentation Conditions for Catalase by Serratia marcescens SYBC08 and Characterization of Its Crude Enzyme

    Institute of Scientific and Technical Information of China (English)

    曾化伟; 张峰; 蔡宇杰; 廖祥儒; 李娇阳; 邢玉鹏; 张大兵

    2011-01-01

    The nutrient and environmental conditions for catalase production by Serratia marcescens SYBC08 were optimized with single factor experiment and orthogonal design in this study. The optimum conditions were listed as follows: 25 g/L citric acid,36 g/L corn steep liquor powder, initial pH 6.75, liquid volume 50 mL/250 mL flask, 4% inoculation, 35 ℃, 250 rpm, for 36 hours. With the optimum conditions, the catalase titer achieved at 9553 U/mL, which was 5.49-fold than that of the control. Properties of the catalase after purification by ammonium sulfate precipitation were studied. At 60 ℃ and pH 9.0, the enzyme was stable for 150 min; at 65 ℃ and pH 9, the half-life of the enzyme was approximately 150 min; its thermo stability was higher than that of commercial catalase from bovine. It was also active at 20 ℃ and had 78% of its activity at 0 ℃. These results suggest that the enzyme displays a property with cold adaption and thermo stability, and it has potential applications in high-temperature, alkaline and lowtemperature conditions.%利用单因素筛选和正交试验对菌株Serratia marcescens SYBC08液态发酵产酶的培养基和条件进行了优化,其最优工艺为:柠檬酸25 g/L,玉米浆粉36 g/L,初始pH值为6.75,接种量为体积分数4%,装液量50 mL,转速250 r/min,35℃培养36 h产酶活力可达9 553 U/mL,是优化前的5.49倍.通过对硫酸铵沉淀得到的过氧化氢酶进行酶学性质研究,该酶在碱性条件(pH值为9.0)条件下,60℃下保温150 min酶活力几乎不变,65℃半衰期为150 min,其比商品化的牛肝过氧化氢酶具有更高的热稳定性.该酶最佳催化温度是20℃,在0℃依然展示了78%的活力.这些结果表明该酶具有良好的冷适应和热稳定性,在高温、碱性条件或极低温条件有应用潜力.

  20. Fractional active disturbance rejection control.

    Science.gov (United States)

    Li, Dazi; Ding, Pan; Gao, Zhiqiang

    2016-05-01

    A fractional active disturbance rejection control (FADRC) scheme is proposed to improve the performance of commensurate linear fractional order systems (FOS) and the robust analysis shows that the controller is also applicable to incommensurate linear FOS control. In FADRC, the traditional extended states observer (ESO) is generalized to a fractional order extended states observer (FESO) by using the fractional calculus, and the tracking differentiator plus nonlinear state error feedback are replaced by a fractional proportional-derivative controller. To simplify controller tuning, the linear bandwidth-parameterization method has been adopted. The impacts of the observer bandwidth ωo and controller bandwidth ωc on system performance are then analyzed. Finally, the FADRC stability and frequency-domain characteristics for linear single-input single-output FOS are analyzed. Simulation results by FADRC and ADRC on typical FOS are compared to demonstrate the superiority and effectiveness of the proposed scheme.

  1. Radiating subdispersive fractional optical solitons

    Energy Technology Data Exchange (ETDEWEB)

    Fujioka, J., E-mail: fujioka@fisica.unam.mx; Espinosa, A.; Rodríguez, R. F. [Departamento de Física Química, Instituto de Física, Universidad Nacional Autónoma de México, Mexico, DF 04510 (Mexico); Malomed, B. A. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

    2014-09-01

    It was recently found [Fujioka et al., Phys. Lett. A 374, 1126 (2010)] that the propagation of solitary waves can be described by a fractional extension of the nonlinear Schrödinger (NLS) equation which involves a temporal fractional derivative (TFD) of order α > 2. In the present paper, we show that there is also another fractional extension of the NLS equation which contains a TFD with α < 2, and in this case, the new equation describes the propagation of radiating solitons. We show that the emission of the radiation (when α < 2) is explained by resonances at various frequencies between the pulses and the linear modes of the system. It is found that the new fractional NLS equation can be derived from a suitable Lagrangian density, and a fractional Noether's theorem can be applied to it, thus predicting the conservation of the Hamiltonian, momentum and energy.

  2. Mechanical Analogies of Fractional Elements

    Institute of Scientific and Technical Information of China (English)

    HU Kai-Xin; ZHU Ke-Qin

    2009-01-01

    A Fractional element model describes a special kind of viscoelastic material.Its stress is proportional to the fractional-order derivative of strain. Physically the mechanical analogies of fractional elements can be represented by spring-dashpot fractal networks. We introduce a constitutive operator in the constitutive equations of viscoelastic materials.To derive constitutive operators for spring-dashpot fractal networks, we use Heaviside operational calculus, which provides explicit answers not otherwise obtainable simply.Then the series-parallel formulas for the constitutive operator are derived. Using these formulas, a constitutive equation of fractional element with 1/2-order derivative is obtained.Finally we find the way to derive the constitutive equations with other fractional-order derivatives and their mechanical analogies.

  3. Permutation entropy of fractional Brownian motion and fractional Gaussian noise

    Energy Technology Data Exchange (ETDEWEB)

    Zunino, L. [Centro de Investigaciones Opticas, C.C. 124 Correo Central, 1900 La Plata (Argentina); Departamento de Ciencias Basicas, Facultad de Ingenieria, Universidad Nacional de La Plata (UNLP), 1900 La Plata (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata (Argentina)], E-mail: lucianoz@ciop.unlp.edu.ar; Perez, D.G. [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso (PUCV), 23-40025 Valparaiso (Chile)], E-mail: dario.perez@ucv.cl; Martin, M.T. [Instituto de Fisica (IFLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata and Argentina' s National Council (CCT-CONICET), C.C. 727, 1900 La Plata (Argentina)], E-mail: mtmartin@fisica.unlp.edu.ar; Garavaglia, M. [Centro de Investigaciones Opticas, C.C. 124 Correo Central, 1900 La Plata (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata (Argentina)], E-mail: garavagliam@ciop.unlp.edu.ar; Plastino, A. [Instituto de Fisica (IFLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata and Argentina' s National Council (CCT-CONICET), C.C. 727, 1900 La Plata (Argentina)], E-mail: plastino@fisica.unlp.edu.ar; Rosso, O.A. [Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, School of Electrical Engineering and Computer Science, The University of Newcastle, University Drive, Callaghan NSW 2308 (Australia); Chaos and Biology Group, Instituto de Calculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellon II, Ciudad Universitaria, 1428 Ciudad de Buenos Aires (Argentina)], E-mail: oarosso@fibertel.com.ar

    2008-06-30

    We have worked out theoretical curves for the permutation entropy of the fractional Brownian motion and fractional Gaussian noise by using the Bandt and Shiha [C. Bandt, F. Shiha, J. Time Ser. Anal. 28 (2007) 646] theoretical predictions for their corresponding relative frequencies. Comparisons with numerical simulations show an excellent agreement. Furthermore, the entropy-gap in the transition between these processes, observed previously via numerical results, has been here theoretically validated. Also, we have analyzed the behaviour of the permutation entropy of the fractional Gaussian noise for different time delays.

  4. In vitro antibacterial efficacy of crude ethanolic leaf extract and alkaloidal fractions of phyllanthus amarus on URO-pathogens

    Directory of Open Access Journals (Sweden)

    Olajide Joseph Akinjogunla

    2012-11-01

    Full Text Available The phytochemistry and in vitro antibacterial efficacy of crude ethanolic leaf extract and alkaloidal fractions of Phyllanthus amarus on the Gram positive (Streptococcus sp, Staphylococcus aureus; Coagulase negative Staphylococcus sp and Enterococcus faecalis and Gram negative bacteria (Escherichia coli, Enterobacter sp.; Serratia marcescens; Klebsiella sp and Pseudomonas aeruginosa isolated from mid stream urine were carried out using standard microbiological and disc diffusion techniques. The preliminary phytochemical analysis of the ethanolic leaf extracts of P. amarus revealed the presence of phyto-constituents such as alkaloids (+++, tannins (+++, saponins (++, flavonoids (++, cardiac glycoside (+, free anthraquinones (++, deoxy-Sugar test (+ and phlobatanins (+, while combined anthraquinones was not detected. The results showed that P. amarus extracts exhibited varying degrees of inhibitory effects against both Gram positive and Gram negative bacteria isolated from urine samples. Highest mean zones of inhibition (14.3+1.0 mm and activity index (0.97 were obtained at 40.0mgml-1 among the Gram positive bacteria, while the highest mean zones of inhibition (14.5 + 0.5mm and activity index (1.12 at 40.0mgml-1 were obtained among the Gram negative. The results also showed that Coagulase negative Staphylococcus sp (CS03 was not sensitive to both 20.0mg/ml-1 of crude extracts of P. amarus and alkaloidal fractions. Among the Gram negative, Enterobacter sp (ES03 was not sensitive to 20.0mg/ml-1 of crude extracts of P. amarus, alkaloidal fractions and Streptomycin. Therefore, there is a need to consider the use of this potent ethanolic leaf extracts and the alkaloids for developing synthetic drugs against uro-pathogens.

  5. 重症监护病房与非重症监护病房粘质沙雷菌耐药性比较%Comparison of drug-resistance of Serratia marcescens between ICU and non-ICU

    Institute of Scientific and Technical Information of China (English)

    倪笑媚; 黄金莲; 胡硕

    2013-01-01

    目的 了解重症监护病房(ICU)与非重症监护病房粘质沙雷菌耐药情况,指导抗生素的合理应用.方法 收集2009年至2010年永康市第一人民医院ICU病房送检标本中分离到的33株粘质沙雷菌与同期非ICU病房送检标本中分离到的26株粘质沙雷菌,对其耐药性进行回顾性分析.结果 ICU与非ICU分离的粘质沙雷菌,除均对头孢他啶、庆大霉素、亚胺培南、左氧氟沙星、哌拉西林/他唑巴坦、复方新诺明耐药外,ICU粘质沙雷菌对氨苄西林/舒巴坦、氨曲南、头孢曲松、头孢唑啉耐药率明显高于非ICU病房(P<0.05),差异有统计学意义.结论 ICU粘质沙雷菌耐药率明显高于非ICU.应及时对ICU患者进行抗生素耐药性检查,根据药敏试验结果选用抗生素,细菌耐药率少于30%的抗菌药物,首先选用,但要考虑感染程度及器官功能状态;耐药率大于75%的药物暂停使用.%Objective To investigate the drug resistance of Serratia marcescens isolated from ICU and non-ICUs, and provide evidences for the clinical reasonable application of antibiotics. Methods From January 2009 to December 2010, 33 strains of Serratia marcescens isolated from ICU and 26 strains from non-ICUs were evaluated by Microscan-Walkaway 40 (American Dade Behring) and their MICs were determined by combined bacterial identification/medicine sensitive analyzer. Statistical retrospective analysis of drug resistance results was conducted. Results Serratia marcescens isolated from both the ICU and non-ICUs were resistant to Ceftazidime, Gentamicin, Imipenem, Levofloxacin, Piperacillin/Tazobactam and Trimethoprim-Sulfamethoxazole. In addition, the pathogens from ICU were more resistant to Ampicillin/Sulbactam, Aztreonam, Ceftriaxone and Cefazolin than those from non-ICUs (P <0.05). Conclusion The rate of drug resistance of ICU Serratia marcescens is higher than that of the non-ICUs. Clinicians should select effective antibiotics

  6. Isolation and Culture Condition of Serratia Marcescens y2 Producing Red Pigment%一株粘质沙雷氏菌的分离和产红色素初步研究

    Institute of Scientific and Technical Information of China (English)

    王飞; 罗海澜; 刘畅; 王建国; 李林珂; 李佳秀; 高宜

    2011-01-01

    从小麦叶表分离到一株产红色素的菌株y2.用16S rDNA序列分析的方法对这株菌进行菌种鉴定,确定为Serratia marcescens y2,产生色素属灵菌红素类色素.PA培养基中添加2%蔗糖和乳糖,0.5%的葡萄糖能促进其色素产生,但4%葡萄糖显著抑制色素产生;培养温度为28℃产色素量最多,38°C不产色素.

  7. 黏质沙雷菌ECU1010脂肪酶新基因lipB的克隆和表达%Cloning and Expression of Novel Lipase Gene lipB from Serratia marcescens ECU1010

    Institute of Scientific and Technical Information of China (English)

    吴娇娇; 李素霞; 赵健; 范立强; 许建和

    2011-01-01

    目的 克隆黏质沙雷菌ECU1010脂肪酶基因lipB于大肠杆菌中表达后研究其酶学性质.方法 PCR克隆脂肪酶基因,与质粒pET-28a(+)连接后转化至大肠杆菌BL21(DE3).硫酸铵沉淀法纯化表达产物,研究酶的稳定性等酶学性质.结果 成功克隆了S.marcescens ECU1010中脂肪酶基因lipB(GenBank:HM440338),在E.coli中高效表达.LipB最适反应温度40℃,最适pH8.5.该酶能在pH5~7条件下保持稳定,Ca有促进酶活性的作用.LipB对不同有机溶剂的耐受性与黏质沙雷菌脂肪酶LipA有明显差异.结论 lipB基因克隆丰富了脂肪酶基因资源,分析LipB的酶学性质表明,此酶在食品工业和手性药物的拆分等领域有广阔的应用前景.%Objective To clone a novel lipase gene lipB from Serratia marcescens ECU1010 and express it in E.coli, then study it' s enzymatic properties. Methods The lipase gene lipB was cloned by PCR and connected with plasmid pET-28a(+), then transformed to E. coli BL21(DE3). The expression product was purified by ammonium sulfate precipitation and it' s enzymatic properties were determined. Results The novel lipase gene lipB(GenBank: HM440338) was successfully cloned from Serratia marcescens ECU1010 and expressed in E. coli. The optimal reaction temperature and pH of lipB were 40℃ and pH 8.5. This enzyme was stable in pH 5~7. Its activity was found to increase in the presence of metal ions such as Ca2+. Compared with the lipase A (lipA) from Serratia marcescens,lipB had different tolerance to various organic solvents. Conclusion The lipase genes can be abundant with the cloning of lipB. The enzymatic properties of lipB determined indicate that this enzyme may have potential value in food industry and resolution of chiral drugs.

  8. 黏质沙雷菌对碳青霉烯类抗生素的耐药性研究%Study on carbapenem resistance characterization of Serratia marcescens

    Institute of Scientific and Technical Information of China (English)

    邹安庆; 费静娴; 吴莲凤; 谢瑶瑶; 周铁丽

    2013-01-01

    Objective To investigate the clinical infection and drug resistance in Serratia marcescens, and analysis its resistance characteristics to carbapenems antibiotic. Methods Retrospective survey the distribution of 109 Serratia marcescens clinical isolated from 2004 to 2010, VITEK-60 automatic microorganism analyzer was used to detect the susceptibility of antibiotics, and minimum inhibitory concentration (MIC) of imipenem, meropenem and ertapenem were detected by agar dilution method. Results The number of Serratia marcescens strains isolated had a upward trend year after year. And the specimen which was from the sputum occupy the most, accounting for 73.4%, followed by urine 12.8% and blood 6.4%; The sensitivity rates of ciprofloxacin, sulfamethoxazole, amikacin, levofloxacin and ceftriaxone were all above 80%, the resistance rates were 8.3% ( 9/109), 5.5% (6/109) and 22.0% (24/109) to imipenem, meropenem, ertapenem respectively. Conclusion Clinical isolates of Serratia marcescens has a fine overall sensitivity to antimicrobial drugs, but there is a high proportion of carbapenem antibiotics resistant, and there is a discrepancy in different carbapenem antibiotics.%目的 了解黏质沙雷菌的临床感染特点和耐药现状,分析其对碳青霉烯类抗生素的耐药特性.方法 回顾性调查2004年-2010年临床分离109株黏质沙雷菌的分布情况,VITEK-60自动化微生物分析仪检测其对临床常用抗菌药物的敏感性,琼脂稀释法测定其对亚胺培南、美罗培南和厄他培南的最低抑菌浓度(MIC).结果 临床分离黏质沙雷菌各年份分离数呈上升趋势.标本来源以痰液标本最多,占73.4%,其次为尿液标本,占12.8%、血液标本,占6.4%;黏质沙雷菌对环丙沙星、复方磺胺甲噁唑、阿米卡星、左氧氟沙星、头孢曲松的敏感率均大于80%,对亚胺培南、美罗培南、厄他培南3种碳青霉烯类抗生素的耐药率分别为8.3%,5.5%和22.0%.结论 临床

  9. SMB-1, a Novel Subclass B3 Metallo-β-Lactamase, Associated with ISCR1 and a Class 1 Integron, from a Carbapenem-Resistant Serratia marcescens Clinical Isolate▿

    Science.gov (United States)

    Wachino, Jun-ichi; Yoshida, Hiroyuki; Yamane, Kunikazu; Suzuki, Satowa; Matsui, Mari; Yamagishi, Takuya; Tsutsui, Atsuko; Konda, Toshifumi; Shibayama, Keigo; Arakawa, Yoshichika

    2011-01-01

    A carbapenem-resistant Serratia marcescens strain, 10mdr148, was identified in a Japanese hospital in 2010. The carbapenem resistance of this strain was attributed to the production of a novel metallo-β-lactamase (MBL), named SMB-1 (Serratia metallo-β-lactamase). SMB-1 possessed a zinc binding motif, H(Q)XHXDH (residues 116 to 121), H196, and H263 and was categorized as a member of subclass B3 MBL. SMB-1 has 75% amino acid identity with the most closely related MBL, AMO1, of uncultured bacterium, recently identified through the metagenomic analysis of apple orchard soil. The introduction of blaSMB-1 into Escherichia coli conferred resistance to a variety of β-lactam antibiotics, penicillins, cephalosporins, and carbapenems, but not aztreonam, a resistance pattern consistent with those of other MBLs. SMB-1 demonstrated high kcat values of >500 s−1 for carbapenems, resulting in the highest hydrolyzing efficiency (kcat/Km) among the agents tested. The hydrolyzing activity of SMB-1 was well inhibited by chelating agents. The blaSMB-1 gene was located on the chromosome of S. marcescens strain 10mdr148 and at the 3′ end of the ISCR1 element in complex with a typical class 1 integron carrying aac(6′)-Ib and catB3 gene cassettes. Downstream of blaSMB-1, the second copy of the 3′conserved segment and ISCR1 were found. To our knowledge, this is the first subclass B3 MBL gene associated with an ISCR1 element identified in an Enterobacteriaceae clinical isolate. A variety of antibiotic resistance genes embedded with ISCR1 have been widely spread among Enterobacteriaceae clinical isolates, thus the further dissemination of blaSMB-1 mediated by ISCR1 transposition activity may become a future concern. PMID:21876060

  10. SMB-1, a novel subclass B3 metallo-beta-lactamase, associated with ISCR1 and a class 1 integron, from a carbapenem-resistant Serratia marcescens clinical isolate.

    Science.gov (United States)

    Wachino, Jun-ichi; Yoshida, Hiroyuki; Yamane, Kunikazu; Suzuki, Satowa; Matsui, Mari; Yamagishi, Takuya; Tsutsui, Atsuko; Konda, Toshifumi; Shibayama, Keigo; Arakawa, Yoshichika

    2011-11-01

    A carbapenem-resistant Serratia marcescens strain, 10mdr148, was identified in a Japanese hospital in 2010. The carbapenem resistance of this strain was attributed to the production of a novel metallo-β-lactamase (MBL), named SMB-1 (Serratia metallo-β-lactamase). SMB-1 possessed a zinc binding motif, H(Q)XHXDH (residues 116 to 121), H196, and H263 and was categorized as a member of subclass B3 MBL. SMB-1 has 75% amino acid identity with the most closely related MBL, AMO1, of uncultured bacterium, recently identified through the metagenomic analysis of apple orchard soil. The introduction of bla(SMB-1) into Escherichia coli conferred resistance to a variety of β-lactam antibiotics, penicillins, cephalosporins, and carbapenems, but not aztreonam, a resistance pattern consistent with those of other MBLs. SMB-1 demonstrated high k(cat) values of >500 s(-1) for carbapenems, resulting in the highest hydrolyzing efficiency (k(cat)/K(m)) among the agents tested. The hydrolyzing activity of SMB-1 was well inhibited by chelating agents. The bla(SMB-1) gene was located on the chromosome of S. marcescens strain 10mdr148 and at the 3' end of the ISCR1 element in complex with a typical class 1 integron carrying aac(6')-Ib and catB3 gene cassettes. Downstream of bla(SMB-1), the second copy of the 3'conserved segment and ISCR1 were found. To our knowledge, this is the first subclass B3 MBL gene associated with an ISCR1 element identified in an Enterobacteriaceae clinical isolate. A variety of antibiotic resistance genes embedded with ISCR1 have been widely spread among Enterobacteriaceae clinical isolates, thus the further dissemination of bla(SMB-1) mediated by ISCR1 transposition activity may become a future concern.

  11. Ferroelectric Fractional-Order Capacitors

    KAUST Repository

    Agambayev, Agamyrat

    2017-07-25

    Poly(vinylidene fluoride)-based polymers and their blends are used to fabricate electrostatic fractional-order capacitors. This simple but effective method allows us to precisely tune the constant phase angle of the resulting fractional-order capacitor by changing the blend composition. Additionally, we have derived an empirical relation between the ratio of the blend constituents and the constant phase angle to facilitate the design of a fractional order capacitor with a desired constant phase angle. The structural composition of the fabricated blends is investigated using Fourier transform infrared spectroscopy and X-ray diffraction techniques.

  12. On Generalized Fractional Differentiator Signals

    Directory of Open Access Journals (Sweden)

    Hamid A. Jalab

    2013-01-01

    Full Text Available By employing the generalized fractional differential operator, we introduce a system of fractional order derivative for a uniformly sampled polynomial signal. The calculation of the bring in signal depends on the additive combination of the weighted bring-in of N cascaded digital differentiators. The weights are imposed in a closed formula containing the Stirling numbers of the first kind. The approach taken in this work is to consider that signal function in terms of Newton series. The convergence of the system to a fractional time differentiator is discussed.

  13. Fractional trajectories: Decorrelation versus friction

    Science.gov (United States)

    Svenkeson, A.; Beig, M. T.; Turalska, M.; West, B. J.; Grigolini, P.

    2013-11-01

    The fundamental connection between fractional calculus and subordination processes is explored and affords a physical interpretation of a fractional trajectory, that being an average over an ensemble of stochastic trajectories. Heretofore what has been interpreted as intrinsic friction, a form of non-Markovian dissipation that automatically arises from adopting the fractional calculus, is shown to be a manifestation of decorrelations between trajectories. We apply the general theory developed herein to the Lotka-Volterra ecological model, providing new insight into the final equilibrium state. The relaxation time to achieve this state is also considered.

  14. Antibiotics resistance and the carbapenems-resistant mechanisms in Serratia marcescens%黏质沙雷菌耐药性及碳青霉烯类抗生素耐药机制研究

    Institute of Scientific and Technical Information of China (English)

    胡丽庆; 吕火祥

    2012-01-01

    Objective To find out the antimicrobial resistance of clinical sequential isolates of Serratia marcescens,investigate the primary antimicrobial resistant mechanism of Serratia marcescens to β-lactams antibiotics.Methods Review the antimicrobial resistance data of 247 Serratia marcescens isolates collected sequentially from different clinical wards during 2007 to 2010 in the First Hospital of Ningbo,which their antimicrobial susceptihility testing was got by using Vitek2-Compact system and matching products of gram-negative susceptibility card (GNS).The antimicrobial resistant genes of 20 carbapenems resistant isolates were detected by PCR.Results The Serratia marcescens resistant rates to ceftriaxone,aztreonarn and ciprofloxacin in our hospital were 70.4% ( 174/247 ),64.8% ( 160/247 ),57.4% ( 142/247),respectively,the resistant rates were lower to amikacin,gentamicin,imipenem and meropenem,which were 3.5% ( 8/229 ),5.4% ( 13/241 ),5.9% ( 14/237 ),8.1% ( 20/247 ),respectively.PCR experiment showed that the expression levels of the AmpC gene in 4 strains were higher than that of the negative reference strains.The expression levels were 98.3,102.3,121.5,87.3 times compared to the negative reference strains,respectively.Twelve strains (strain no.2,3,5,6,9,10,14,15,16,17,18 and 19) produce both blaCTX-M and blaKPC-2 enzymes.Highly deteced hlaCTX-M of Serratia marcescens in our hospital included CTX-M1,CTX-M2,CTX-M9.Isolates no.7 and 18 were carrying blaSHV gene,Isolates no.8 and 13 were carrying blaSME,Isolates no.11 and 20 were carrying blaTEM.There were 5 strains (no.3,4,5,7 and 16) lose the outer membrane protein (OMP) genes ompC and ompF.Two strains( no.1 and 12 ) lose OMP gene ompF only,and one strain ( no.20 ) was lose OMP gene ompC only.Conclusions The cause of β-lactam antibiotics resistance of Serratia marcescens was complicated,and the most important mechanism is producing β-1actams and loss of OMP.Understanding the evolution and drug

  15. Drug resistance rate and multilocus sequence analysis of Serratia marcescens isolates%褪色沙雷菌耐药率与多位点序列分析研究

    Institute of Scientific and Technical Information of China (English)

    赵瑞珂; 顾国浩; 韩清珍; 赵丽娜; 钱雪峰; 张险峰; 史进方; 徐杰

    2016-01-01

    目的:研究褪色沙雷菌的耐药率与分子流行病学规律,建立多位点序列分析方法,明确其进化特征,为临床针对性使用抗菌药物和防控此致病菌感染提供依据。方法对2013年9月-2014年12月分离的40株褪色沙雷菌进行体外药物敏感性试验与多位点序列分析(MLSA),并用Splits tree与CLUSTALW软件进行生物信息学分析,揭示其流行趋势。结果体外药敏试验结果表明,40株褪色沙雷菌对13种抗菌药物的耐药率在10.0%~52.5%,对亚胺培南耐药率为32.5%;M LSA设计4个管家基因,GC含量约为60.0%;各等位基因数分布于14~16,各多态性位点数分布于33~74,gyrB的多态性位点数最多(74个);Splits tree软件分裂分解分析结果显示,大部分褪色沙雷菌聚在一起,形成一个克隆复合体;CLUSTALW软件聚类分析结果显示,40株褪色沙雷菌形成19个ST型,其中ST8型12株,且ST8型是耐碳青霉烯类抗菌药物褪色沙雷菌的流行与暴发型, ST8、ST9、ST10与ST11形成一个克隆复合体CC8。结论褪色沙雷菌对碳青霉烯类抗菌药物耐药率较高,且多为泛耐药菌株;褪色沙雷菌的分子流行病学趋势相对较慢,在基因组上高度保守,目前需要重点监测以ST8型为代表褪色沙雷菌CC8克隆复合体的流行,以防其在医院的大规模流行与暴发。%OBJECTIVE To study the drug resistance rate and molecular epidemiological characteristics ,establish the multilocus sequence analysis (MLSA) ,method ,define the evolutionary characteristics so as to provide guid‐ance for clinical use of antibiotics and prevention of infection caused by this species of pathogen .METHODS The in vitro drug susceptibility testing and MLSA were conducted for 40 strains of Serratia marcescens that were isolated from Sep 2013 to Dec 2014 ,and the biological information was analyzed by using Splits tree and CLUSTALW

  16. Solutions of fractional diffusion problems

    Directory of Open Access Journals (Sweden)

    Rabha W. Ibrahim

    2010-10-01

    Full Text Available Using the concept of majorant functions, we prove the existence and uniqueness of holomorphic solutions to nonlinear fractional diffusion problems. The analytic continuation of these solutions is studied and the singularity for two cases are posed.

  17. Australia's Next Top Fraction Model

    Science.gov (United States)

    Gould, Peter

    2013-01-01

    Peter Gould suggests Australia's next top fraction model should be a linear model rather than an area model. He provides a convincing argument and gives examples of ways to introduce a linear model in primary classrooms.

  18. Fractional Dynamics of Relativistic Particle

    CERN Document Server

    Tarasov, Vasily E

    2011-01-01

    Fractional dynamics of relativistic particle is discussed. Derivatives of fractional orders with respect to proper time describe long-term memory effects that correspond to intrinsic dissipative processes. Relativistic particle subjected to a non-potential four-force is considered as a nonholonomic system. The nonholonomic constraint in four-dimensional space-time represents the relativistic invariance by the equation for four-velocity u_{\\mu} u^{\\mu}+c^2=0, where c is a speed of light in vacuum. In the general case, the fractional dynamics of relativistic particle is described as non-Hamiltonian and dissipative. Conditions for fractional relativistic particle to be a Hamiltonian system are considered.

  19. Physcicists rewarded for 'fractional electrons'

    CERN Multimedia

    Ball, P

    1998-01-01

    The 1998 Nobel prize for physics has been awarded to Horst Stormer, Daniel Tsui and Robert Laughlin.Stormer and Tsui were the first to observe the fractional quantum Hall effect and Laughlin provided the theory shortly afterwards (1 page).

  20. Commercial SNF Accident Release Fractions

    Energy Technology Data Exchange (ETDEWEB)

    J. Schulz

    2004-11-05

    The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M&O 1999). In contrast to bare unconfined fuel assemblies, the

  1. Concurrent fractional and equilibrium crystallisation

    Science.gov (United States)

    Sha, Lian-Kun

    2012-06-01

    This paper proposes the concept of concurrent fractional and equilibrium crystallisation (CFEC) in a multi-phase magmatic system in light of experimental results on diffusivities of elements and other species in minerals and melts. A group of equations are presented to describe how the concentrations of an element or isotope change in fractionated solid, equilibrated solid, melt, liquid, and gas phases, as well as in magma, as a function of distribution coefficients and mass fractions during the CFEC process. CFEC model is a generalised and unified formulation that is valid, not only for pure fractional crystallisation (FC) and perfect equilibrium crystallisation (EC) singly, as two of its limiting end-member cases, but also for the geologically more important process of concurrent fractional and equilibrium crystallisation. The concept that both fractional and equilibrium crystallisation can operate concurrently in a magmatic system, for a given element, among different minerals, and even within different-sized crystal grains of the very same mineral phase, is of fundamental importance in deepening our current understanding of magmatic differentiation processes. CFEC probably occurs more frequently in the natural world than either pure fractional or perfect equilibrium crystallisation alone, as a result of the interplay of varying diffusivities of elements under diverse physicochemical conditions, different residence time and growth rates of mineral phases in magmas, and varying grain sizes within each phase and among different phases. The marked systematic variations in trace element concentrations in the melts of the Bishop Tuff have long been perplexing and difficult to reconcile with existing models of differentiation. CFEC, which is able to better explain the scatter trends in a systematic way than fractional crystallisation, is considered to be the cause.

  2. The Periodogram of fractional processes

    OpenAIRE

    Velasco, Carlos

    2007-01-01

    We analyse asymptotic properties of the discrete Fourier transform and the periodogram of time series obtained through (truncated) linear filtering of stationary processes. The class of filters contains the fractional differencing operator and its coefficients decay at an algebraic rate, implying long-range-dependent properties for the filtered processes when the degree of integration α is positive. These include fractional time series which are nonstationary for any value of the memory param...

  3. Fractional Reserve Banking: Some Quibbles

    OpenAIRE

    Bagus, Philipp; Howden, David

    2010-01-01

    We explore several unaddressed issues in George Selgin’s (1988) claim that the best monetary system to maintain monetary equilibrium is a fractional reserve free banking one. The claim that adverse clearing balances would limit credit expansion in a fractional reserve free banking system is more troublesome than previously reckoned. Both lengthened clearing periods and interbank agreements render credit expansion unrestrained. “The theory of free banking” confuses increases in money held with...

  4. Xenon fractionation in porous planetesimals.

    Science.gov (United States)

    Zahnle, K; Pollack, J B; Kasting, J F

    1990-01-01

    The distinctively fractionated Xe on Mars and Earth may have its root in a common source from which both planets accreted. We begin with Ozima and Nakazawa's hypothesis that terrestrial Xe fractionation was caused by gravitational separation of adsorbed solar nebular gases inside large porous planetesimals. We point out that Xe would have been trapped as the planetesimal grew and pores were squeezed shut by lithostatic pressure. We show that enough fractionated Xe to supply the Earth could have been trapped this way. The degree of fractionation is controlled by the lithostatic pressure at the pore-closing front and so would have been roughly the same for all large planetesimals. The predicted degree of fractionation agrees well with that preserved in terrestrial and martian Xe. Relative to Xe, this source is strongly depleted in other noble gases. In contrast to the original Ozima and Nakazawa hypothesis, our hypothesis predicts the observed fractionation, and it allows planetary accretion to occur after the dissipation of the solar nebula. The required planetesimals are large, representing a class of object now extinct in the solar system.

  5. Fractional Charge Definitions and Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Goldhaber, A.S.

    2004-06-04

    Fractional charge is known through theoretical and experimental discoveries of isolable objects carrying fractions of familiar charge units--electric charge Q, spin S, and the difference of baryon and lepton numbers B-L. With a few simple assumptions all these effects may be described using a generalized version of charge renormalization for locally conserved charges, in which medium correlations yield familiar adiabatic, continuous renormalization, or sometimes nonadiabatic, discrete renormalization. Fractional charges may be carried by fundamental particles or fundamental solitons. Either picture works for the simplest fractional-quantum-Hall-effect quasiholes, though the particle description is far more general. The only known fundamental solitons in three or fewer space dimensions d are the kink (d = 1), the vortex (d = 2), and the magnetic monopole (d = 3). Further, for a charge not intrinsically coupled to the topological charge of a soliton, only the kink and the monopole may carry fractional values. The same reasoning enforces fractional values of B-L for electrically charged elementary particles.

  6. Fractional characteristic times and dissipated energy in fractional linear viscoelasticity

    Science.gov (United States)

    Colinas-Armijo, Natalia; Di Paola, Mario; Pinnola, Francesco P.

    2016-08-01

    In fractional viscoelasticity the stress-strain relation is a differential equation with non-integer operators (derivative or integral). Such constitutive law is able to describe the mechanical behavior of several materials, but when fractional operators appear, the elastic and the viscous contribution are inseparable and the characteristic times (relaxation and retardation time) cannot be defined. This paper aims to provide an approach to separate the elastic and the viscous phase in the fractional stress-strain relation with the aid of an equivalent classical model (Kelvin-Voigt or Maxwell). For such equivalent model the parameters are selected by an optimization procedure. Once the parameters of the equivalent model are defined, characteristic times of fractional viscoelasticity are readily defined as ratio between viscosity and stiffness. In the numerical applications, three kinds of different excitations are considered, that is, harmonic, periodic, and pseudo-stochastic. It is shown that, for any periodic excitation, the equivalent models have some important features: (i) the dissipated energy per cycle at steady-state coincides with the Staverman-Schwarzl formulation of the fractional model, (ii) the elastic and the viscous coefficients of the equivalent model are strictly related to the storage and the loss modulus, respectively.

  7. From fractional Fourier transformation to quantum mechanical fractional squeezing transformation

    Institute of Scientific and Technical Information of China (English)

    吕翠红; 范洪义; 李东韡

    2015-01-01

    By converting the triangular functions in the integration kernel of the fractional Fourier transformation to the hy-perbolic function, i.e., tanα→tanhα, sinα→sinhα, we find quantum mechanical fractional squeezing transformation (FrST) which satisfies additivity. By virtue of the integration technique within ordered product of operators (IWOP) wederive the unitary operator responsible for the FrST, which is composite and is made of eiπa†a/2 and exp[ iα2 (a2+a†2)]. The FrST may be implemented in combinations of quadratic nonlinear crystals with different phase mismatches.

  8. Isolation and Identification of Serratia marcescens Yj1, and Separation and Purification of Organophosphate Degrading Enzymes%沙雷氏菌(Serratia marcescens)Yj1的分离鉴定及菌体有机磷降解酶的分离纯化

    Institute of Scientific and Technical Information of China (English)

    于亭; 王春红; 张婷婷; 汲添; 武志海; 杨美英

    2015-01-01

    从大豆土壤中分离纯化得到一株具有卵磷脂和乐果降解能力的菌株Yj1,对该菌株进行鉴定、生长条件优化、酶活性鉴定以及有机磷降解酶的分离纯化.结果表明,Yj1与Serratia marcescens WW4(CP003959.1)的16S rDNA相似度为99%.正交试验对所需培养基进行优化,得到该菌株的最佳生长条件为甘露糖、蛋白胨和pH 8的组合.Yj1菌株在两种磷源条件下,菌株生长量均很低,但72 h内以大豆卵磷脂为磷源时的菌体生长情况优于乐果.以大豆卵磷脂为磷源时酸性磷酸酶、碱性磷酸酶与有机磷降解酶活性明显高于以乐果为磷源时的酶活,且72 h内碱性磷酸酶活性一直都高于酸性磷酸酶和有机磷降解酶.硫酸铵沉淀法结合阳离子交换层析成功从Yj1菌体中分离纯化了有机磷降解酶,SDS-PAGE结果显示纯化的蛋白为单一条带.且阳离子交换层析的提纯倍数是硫酸氨沉淀的5.303倍,硫酸氨沉淀为粗酶的1.416倍.

  9. FRACTIONAL TRANSPORT OF SEDIMENT MIXTURES

    Institute of Scientific and Technical Information of China (English)

    Baosheng WU; Albert MOLINAS; Anping SHU

    2003-01-01

    A new method based on the Transport Capacity Fraction (TCF) concept is proposed to compute the fractional transport rates for nonuniform sediment mixtures in sand-bed channels. The TCF concept is derived from the understanding that the measurements and predictions of bed-material load are more accurate and reliable than the measurements and predictions of fractional loads. First the bed-material load is computed using an appropriate equation, then the fractional transport rates are determined by distributing the bed-material load into size groups through a transport capacity distribution function. For the computation of bed-material loads, the Aekers and White, Engelund and Hansen, and Yang equations are used in this study. Two new transport capacity distribution functions are developed for flows in sand-bed channels. The new expressions presented in this paper account for the sheltering and exposure effects that exist in mixtures. Comparisons with measured data show that the proposed method can significantly improve the predictions of fractional transport rates for nonuniform sediment mixtures.

  10. Phytotoxic characterization of various fractions of Launaea ...

    African Journals Online (AJOL)

    Administrator

    2011-06-15

    Jun 15, 2011 ... Abbreviations: DMSO, Dimethyl sulfoxide; LPME, Launaea procumbens ... 1, non treated control; 2, n-hexane fraction; 3, ethyl acetate fraction; ... fractionated using n-hexane, ethyl acetate, chloroform, butanol and distilled ...

  11. REFractions: The Representing Equivalent Fractions Game

    Science.gov (United States)

    Tucker, Stephen I.

    2014-01-01

    Stephen Tucker presents a fractions game that addresses a range of fraction concepts including equivalence and computation. The REFractions game also improves students' fluency with representing, comparing and adding fractions.

  12. Type-2 fuzzy fractional derivatives

    Science.gov (United States)

    Mazandarani, Mehran; Najariyan, Marzieh

    2014-07-01

    In this paper, we introduce two definitions of the differentiability of type-2 fuzzy number-valued functions of fractional order. The definitions are in the sense of Riemann-Liouville and Caputo derivative of order β ɛ (0, 1), and based on type-2 Hukuhara difference and H2-differentiability. The existence and uniqueness of the solutions of type-2 fuzzy fractional differential equations (T2FFDEs) under Caputo type-2 fuzzy fractional derivative and the definition of Laplace transform of type-2 fuzzy number-valued functions are also given. Moreover, the approximate solution to T2FFDE by a Predictor-Evaluate-Corrector-Evaluate (PECE) method is presented. Finally, the approximate solutions of two examples of linear and nonlinear T2FFDEs are obtained using the PECE method, and some cases of T2FFDEs applications in some sciences are presented.

  13. Optical encryption with cascaded fractional wavelet transforms

    Institute of Scientific and Technical Information of China (English)

    BAO Liang-hua; CHEN Lin-fei; ZHAO Dao-mu

    2006-01-01

    On the basis of fractional wavelet transform, we propose a new method called cascaded fractional wavelet transform to encrypt images. It has the virtues of fractional Fourier transform and wavelet transform. Fractional orders, standard focal lengths and scaling factors are its keys. Multistage fractional Fourier transforms can add the keys easily and strengthen information security. This method can also realize partial encryption just as wavelet transform and fractional wavelet transform. Optical realization of encryption and decryption is proposed. Computer simulations confirmed its possibility.

  14. Homology analysis of Serratia marcescens strains causing blood stream infection in an intensive care unit%引发重症监护室内血流感染的粘质沙雷菌同源性分析

    Institute of Scientific and Technical Information of China (English)

    陈炜; 甄国东; 赵琼; 邓梅; 毕晟; 盛吉芳

    2015-01-01

    目的:分析从绍兴市中心医院重症监护室( ICU)内血流感染患者中分离的粘质沙雷菌株的同源性和耐药情况,为临床合理用药及感染控制提供依据。方法收集ICU病房2013年6月至2013年9月血流感染中分离培养出来的粘质沙雷菌株,并从ICU医务人员手上采集细菌,进行分离培养。对培养出的17株粘质沙雷菌进行药敏检测,用PCR技术扩增常见耐药基因,使用脉冲场凝胶电泳( PFGE)技术进行同源性分析。收集患者的临床资料,用Spearman相关法进行统计学分析。结果17株粘质沙雷菌对第一代、二代头孢霉素、庆大霉素、环丙沙星耐药率100%,对阿米卡星及头孢他啶敏感,对碳青酶烯类的耐药率为11.76%~35.29%,PCR扩增结果显示1(5.88%)株粘质沙雷菌携带TEM基因,17株粘质沙雷菌PFGE分型一致。结论粘质沙雷菌是重要的致病菌,存在着院内传播现象,具有多重耐药性。临床应根据药敏试验合理选用抗菌药物,加强感染控制,防止耐药菌株在院内交叉传播和暴发流行。%Objective To provide the guidance for the control and treatment of blood stream infec-tion caused by Serratia marcescens strains through analyzing the homology and drug resistant genes of the iso-lates collected from the Intensive Care Unit ( ICU) of Shaoxing County Central Hospital.Methods Serratia marcescens strains were isolated from ICU patients with blood stream infection and also from the hands of health care providers in the ICU from June 1st to September 30th, 2013.The antibiotic susceptibilities of the Serratia marcescens isolates were tested.PCR was performed to amplify the common drug resistant genes. Pulse-field gel electrophoresis ( PFGE) was carried out for analyzing the homology of all isolates.The com-plete clinical data of the patients were collected and statistically analyzed with Spearman′s rank correlation coefficient

  15. Experimental phage therapy against Serratia marcescens infection in BALB/c mice%噬菌体对黏质沙雷菌感染 BA LB/c小鼠的保护作用

    Institute of Scientific and Technical Information of China (English)

    徐花; 李毅; 逯茵茵; 周佳琦; 韩放; 李诗恒; 孙延波

    2015-01-01

    本文旨在观察噬菌体对黏质沙雷菌感染小鼠的治疗作用,为噬菌体疗法应用于细菌性感染提供依据。以黏质沙雷菌为宿主菌,采用双层琼脂噬斑法从污水中分离和纯化裂解性噬菌体。将最小致死量的黏质沙雷菌经腹腔感染BALB/c小鼠后,立即腹腔注射不同剂量的噬菌体,观察动物的生存率并确定噬菌体的保护剂量。在动物感染后的不同时间(0、20、40、60和180 min )观察噬菌体疗法对动物存活率的影响。将噬菌体和细菌同时或分别注射动物后,分析噬菌体在动物体内的药代动力学。结果显示,经噬斑法从污水中分离出1株裂解性噬菌体(命名为φSM9‐3Y ),电镜观察发现该噬菌体属有尾噬菌体目肌尾噬菌体科。动物腹腔感染黏质沙雷菌并立即给予噬菌体后发现,当噬菌体的保护剂量为108 PFU/ml时,动物的存活率为100%。动物感染后40和60 min给予噬菌体(1010 PFU/ml)治疗,动物的存活率为60%。药代动力学表明,将噬菌体和细菌同时注入动物体内,在6 h内噬菌体的滴度维持在1010 PFU/ml。结果提示,噬菌体对黏质沙雷菌所致动物腹腔内感染的治疗是有效的,提示针对细菌性感染的噬菌体疗法具有潜在的应用价值。%This study aims to evaluate the efficacy of phage therapy against Serratia marcescens infections in mice and to provide the basis of phage therapy applied in bacterial infections .Double‐agar overlay plaque method was employed to screen lytic phages from sewage , using Serratia marcescens isolates as hosts . Serratia marcescens strains at minimal lethal dose (MLD) were injected intraperitoneally (i .p .) into BALB/c mice and an i .p .of phage was followed .The survival rate of animals and protective dose of phage were examined at different time points (0 , 20 , 40 , 60 and 180 min ) after the bacterial challenge . Pharmacokinetics of phages

  16. Fractional Derivatives in Dengue Epidemics

    Science.gov (United States)

    Pooseh, Shakoor; Rodrigues, Helena Sofia; Torres, Delfim F. M.

    2011-09-01

    We introduce the use of fractional calculus, i.e., the use of integrals and derivatives of non-integer (arbitrary) order, in epidemiology. The proposed approach is illustrated with an outbreak of dengue disease, which is motivated by the first dengue epidemic ever recorded in the Cape Verde islands off the coast of west Africa, in 2009. Numerical simulations show that in some cases the fractional models fit better the reality when compared with the standard differential models. The classical results are obtained as particular cases by considering the order of the derivatives to take an integer value.

  17. On a fractional difference operator

    Directory of Open Access Journals (Sweden)

    P. Baliarsingh

    2016-06-01

    Full Text Available In the present article, a set of new difference sequence spaces of fractional order has been introduced and subsequently, an application of these spaces, the notion of the derivatives and the integrals of a function to the case of non-integer order have been generalized. Certain results involving the unusual and non-uniform behavior of the corresponding difference operator have been investigated and also been verified by using some counter examples. We also verify these unusual and non-uniform behaviors by studying the geometry of fractional calculus.

  18. A Fast Fractional Difference Algorithm

    DEFF Research Database (Denmark)

    Jensen, Andreas Noack; Nielsen, Morten Ørregaard

    We provide a fast algorithm for calculating the fractional difference of a time series. In standard implementations, the calculation speed (number of arithmetic operations) is of order T 2, where T is the length of the time series. Our algorithm allows calculation speed of order T logT . For mode......We provide a fast algorithm for calculating the fractional difference of a time series. In standard implementations, the calculation speed (number of arithmetic operations) is of order T 2, where T is the length of the time series. Our algorithm allows calculation speed of order T log...

  19. Fractional Boundaries for Fluid Spheres

    CERN Document Server

    Bayin, S; Krisch, J P; Bayin, Selcuk; Krisch, Jean P.

    2006-01-01

    A single Israel layer can be created when two metrics adjoin with no continuous metric derivative across the boundary. The properties of the layer depend only on the two metrics it separates. By using a fractional derivative match, a family of Israel layers can be created between the same two metrics. The family is indexed by the order of the fractional derivative. The method is applied to Tolman IV and V interiors and a Schwarzschild vacuum exterior. The method creates new ranges of modeling parameters for fluid spheres. A thin shell analysis clarifies pressure/tension in the family of boundary layers.

  20. Fractional derivatives in Dengue epidemics

    CERN Document Server

    Pooseh, Shakoor; Torres, Delfim F M

    2011-01-01

    We introduce the use of fractional calculus, i.e., the use of integrals and derivatives of non-integer (arbitrary) order, in epidemiology. The proposed approach is illustrated with an outbreak of dengue disease, which is motivated by the first dengue epidemic ever recorded in the Cape Verde islands off the coast of west Africa, in 2009. Numerical simulations show that in some cases the fractional models fit better the reality when compared with the standard differential models. The classical results are obtained as particular cases by considering the order of the derivatives to take an integer value.

  1. Staircase and Fractional Part Functions

    Science.gov (United States)

    Amram, Meirav; Dagan, Miriam; Ioshpe, Michael; Satianov, Pavel

    2016-01-01

    The staircase and fractional part functions are basic examples of real functions. They can be applied in several parts of mathematics, such as analysis, number theory, formulas for primes, and so on; in computer programming, the floor and ceiling functions are provided by a significant number of programming languages--they have some basic uses in…

  2. Fractional Laplace Transforms - A Perspective

    CERN Document Server

    Treumann, R A

    2014-01-01

    A form of the Laplace transform is reviewed as a paradigm for an entire class of fractional functional transforms. Various of its properties are discussed. Such transformations should be useful in application to differential/integral equations or problems in non-extensive statistical mechanics.

  3. Subcellular fractionation of rough microsomes.

    Science.gov (United States)

    Sabatini, David D

    2014-09-02

    When eukaryotic cells are homogenized, the rough endoplasmic reticula are converted into small vesicles, called rough microsomes. Strategies for the isolation of rough microsomes are introduced here, as are methods for evaluating the purity and intactness of an isolated rough microsomal fraction.

  4. Working with a fractional object:

    DEFF Research Database (Denmark)

    Christensen, Bodil Just; Hillersdal, Line; Holm, Lotte

    2017-01-01

    constitutes ‘appetite’ was a key concern, as each discipline has its particular definition and operationalization of the term. In response, a material-semiotic approach was chosen which allowed for a reconceptualization of appetite as a ‘fractional object’, engaged in multiple relations and enacted...

  5. Complexity and the Fractional Calculus

    Science.gov (United States)

    2013-01-01

    developed in a number of signif- icant ways in the recent past. Sokolov et al. [1] maintain that this calculus was restricted to the field of mathematics... Sokolov , J. Klafter, and A. Blumen, “Fractional kinetics,” Physics Today, vol. 55, no. 11, pp. 48–54, 2002. [2] V. Seshadri and B. J. West, “Fractal

  6. Fractional Laplace Transforms - A Perspective

    Directory of Open Access Journals (Sweden)

    Rudolf A. Treumann

    2014-06-01

    Full Text Available A new form of the Laplace transform is reviewed as a paradigm for an entire class of fractional functional transforms. Various of its properties are discussed. Such transformations should be useful in application to differential/integral equations or problems in non-extensive statistical mechanics.

  7. A note on fractional supersolutions

    Directory of Open Access Journals (Sweden)

    Janne Korvenpaa

    2016-09-01

    Full Text Available We study a class of equations driven by nonlocal, possibly degenerate, integro-differential operators of differentiability order $s\\in (0,1$ and summability growth $p>1$, whose model is the fractional $p$-Laplacian with measurable coefficients. We prove that the minimum of the corresponding weak supersolutions is a weak supersolution as well.

  8. Math Fair: Focus on Fractions

    Science.gov (United States)

    Mokashi, Neelima A.

    2009-01-01

    This article depicts the rewarding experience of creating mathematical environments for kindergarten and elementary students by focusing on one of the most important and often difficult-to-grasp concepts (fractions) through play methods incorporated into a math fair. The basic concept of a math fair is threefold: (1) to create preplanned,…

  9. Pythagorean Approximations and Continued Fractions

    Science.gov (United States)

    Peralta, Javier

    2008-01-01

    In this article, we will show that the Pythagorean approximations of [the square root of] 2 coincide with those achieved in the 16th century by means of continued fractions. Assuming this fact and the known relation that connects the Fibonacci sequence with the golden section, we shall establish a procedure to obtain sequences of rational numbers…

  10. Riesz potential versus fractional Laplacian

    KAUST Repository

    Ortigueira, Manuel Duarte

    2014-09-01

    This paper starts by introducing the Grünwald-Letnikov derivative, the Riesz potential and the problem of generalizing the Laplacian. Based on these ideas, the generalizations of the Laplacian for 1D and 2D cases are studied. It is presented as a fractional version of the Cauchy-Riemann conditions and, finally, it is discussed with the n-dimensional Laplacian.

  11. Fractional diffusion: recovering the distributed fractional derivative from overposed data

    Science.gov (United States)

    Rundell, W.; Zhang, Z.

    2017-03-01

    There has been considerable recent study in ‘subdiffusion’ models that replace the standard parabolic equation model by a one with a fractional derivative in the time variable. There are many ways to look at this newer approach and one such is to realize that the order of the fractional derivative is related to the time scales of the underlying diffusion process. This raises the question of what order α of derivative should be taken and if a single value actually suffices. This has led to models that combine a finite number of these derivatives each with a different fractional exponent {αk} and different weighting value c k to better model a greater possible range of time scales. Ultimately, one wants to look at a situation that combines derivatives in a continuous way—the so-called distributional model with parameter μ ≤ft(α \\right) . However all of this begs the question of how one determines this ‘order’ of differentiation. Recovering a single fractional value has been an active part of the process from the beginning of fractional diffusion modeling and if this is the only unknown then the markers left by the fractional order derivative are relatively straightforward to determine. In the case of a finite combination of derivatives this becomes much more complex due to the more limited analytic tools available for such equations, but recent progress in this direction has been made, (Li et al 2015 Appl. Math. Comput. 257 381–97, Li and Yamamoto 2015 Appl. Anal. 94 570–9). This paper considers the full distributional model where the order is viewed as a function μ ≤ft(α \\right) on the interval (0, 1]. We show existence, uniqueness and regularity for an initial-boundary value problem including an important representation theorem in the case of a single spatial variable. This is then used in the inverse problem of recovering the distributional coefficient μ ≤ft(α \\right) from a time trace of the solution and a uniqueness result is

  12. 黏质沙雷氏菌C8-8几丁质酶基因的克隆与表达%Cloning and expression of a chitinase gene from Serratia marcescens strain C8-8

    Institute of Scientific and Technical Information of China (English)

    刘邮洲; 罗楚平; 刘永锋; 陈志谊

    2012-01-01

    利用PCR方法从黏质沙雷氏菌(Serratia marcescens)C8-8中克隆到编码几丁质酶的chiA基因,大小为1692bp,推测其编码一条长563个氨基酸的多肽链,分子量约为60900.同源分析研究结果表明从C8-8中克隆的chiA基因序列与黏质沙雷氏菌株141(DQ990373.1)和14041菌株(DQ493896.1)的chiA基因序列相似性最高,达到99%.结构域分析结果表明从C8-8中克隆的chiA基因N末端(23AA)存在典型的信号肽序列,C端存在另外两个结构域,即PKD区(73AA)和几丁质酶催化区(387AA).采用大肠杆菌表达系统重组表达chiA基因,结果表明重组菌株在几丁质诱导培养基上能产生透明的水解圈.采用SDS-PAGE电泳分析,结果表明chiA重组表达产物的相对分子质量约为60000,与预测分子量大小基本一致.初步提纯后,生物活性试验结果表明该重组表达产物能水解几丁质,在几丁质培养基上产生透明的水解圈.%An open reading frame encoding chiA gene was cloned from the Serratia marcescens strain C8-8 genomic DNA by PCR, with the length of 1 692 bp. Its sequence was 99% identical with chiA sequences of Serratia marcescens 141 and 14041. Domain analysis showed that the cloned chiA gene involved a typical signal peptide sequence at N-terraination (23 AA), and PKD domain (73 AA) and chitinase catalytic domain (387 AA) at C-termination. The PCR fragment was digested and cloned into plasmid pET28a to construct plasmid pET28a-ChiA, which was then transformed into expression host Escherichia. coli DH3. The recombined strain DH3 ChiA could yield transparent hydrolyzed zone on the colloidal chi-tin plate induced by isopropyl-1 -thiogalactopyranoside (IPTG). A protein with molecular weight about 60 000 was expressed by DH3 ChiA, and could also yield a hydrolyzed rone on the colloidal chitin plate. It indicated that chiA gene from C8-8 could be utilized as a potential biological factor for control of fungi.

  13. Addition of Ctric Acid for Stimulating Catalase Accumulation by Serratia marcescens%添加柠檬酸促进粘质沙雷氏菌发酵产过氧化氢酶

    Institute of Scientific and Technical Information of China (English)

    贺仁艳; 蔡宇杰; 廖祥儒; 李婷婷; 张大兵

    2011-01-01

    在优化1株粘质沙雷氏菌发酵产过氧化氢酶(CAT)的培养基成分时发现,柠檬酸可以显著提高该菌胞内CAT的活力。结合先前报道,探究了柠檬酸促进粘质沙雷氏菌合成胞内CAT的原因。以等摩尔碳含量的柠檬酸、葡萄糖、柠檬酸与葡萄糖的混合物分别作为碳源,测定了在不同碳源发酵产CAT时粘质沙雷氏菌胞内抗氧化的相关数据。结果显示:添加柠檬酸(20g/L)后,该菌细胞内H2O2和羟自由基含量均比对照组(葡萄糖)高,说明柠檬酸代谢物对其产生了活性氧胁迫,进而诱导更多CAT的合成。考察了甲萘醌和百草枯(活性氧O2^-·的来源物)对该菌合成CAT的影响,实验结果验证了适量的活性氧能够诱导该菌合成CAT的结论。%In an experiment to optimize the culture conditions for the catalase(CAT) production by Serratia marcescens SYBCT02,an interesting phenomenon occurred that the addition of ctric acid to the culture medium significantly stimulated the accumulation of CAT.To explore the reason for this finding,an experiment was designed based on the previous reports.Three kinds of carbon source,i.e.glucose,ctric acid and a mixture constituted by glucose and citric acid,with the same amount of carbon element,were used in the culture medium for CAT production by Serratia marcescens SYBCT02.After determining the contents of cellular antioxidant substrates and the activities of cellular antioxidant enzymes,an occurrence of oxidative stress was found in the cells of Serratia marcescens SYBCT02 cultivated in the media with citric acid.Compared with the control,the increased amounts of hydrogen peroxide(H2O2) and hydroxyl radical( ·OH ) induced the synthesis of CAT after an addition of citric acid to the culture medium. This conclusion was further confirmed by the addition of exogenous reactive oxygen(produced by menadione and paraquat) to the culture media.

  14. Galaxy Cluster Baryon Fractions Revisited

    Science.gov (United States)

    Gonzalez, Anthony H.; Sivanandam, Suresh; Zabludoff, Ann I.; Zaritsky, Dennis

    2013-11-01

    We measure the baryons contained in both the stellar and hot-gas components for 12 galaxy clusters and groups at z ~ 0.1 with M = 1-5 × 1014 M ⊙. This paper improves upon our previous work through the addition of XMM-Newton X-ray data, enabling measurements of the total mass and masses of each major baryonic component—intracluster medium, intracluster stars, and stars in galaxies—for each system. We recover a mean relation for the stellar mass versus halo mass, M_{\\star }\\propto M_{500}^{-0.52+/- 0.04}, that is 1σ shallower than in our previous result. We confirm that the partitioning of baryons between the stellar and hot-gas components is a strong function of M 500; the fractions of total mass in stars and X-ray gas within a sphere of radius r 500 scale as f_{\\star }\\propto M_{500}^{-0.45+/- 0.04} and f_{gas}\\propto M_{500}^{0.26+/- 0.03}, respectively. We also confirm that the combination of the brightest cluster galaxy and intracluster stars is an increasingly important contributor to the stellar baryon budget in lower halo masses. Studies that fail to fully account for intracluster stars typically underestimate the normalization of the stellar baryon fraction versus M 500 relation by ~25%. Our derived stellar baryon fractions are also higher, and the trend with halo mass weaker, than those derived from recent halo occupation distribution and abundance matching analyses. One difference from our previous work is the weak, but statistically significant, dependence here of the total baryon fraction upon halo mass: f_{bary}\\propto M_{500}^{0.16+/- 0.04}. For M 500 >~ 2 × 1014, the total baryon fractions within r 500 are on average 18% below the universal value from the seven year Wilkinson Microwave Anisotropy Probe (WMAP) analysis, or 7% below for the cosmological parameters from the Planck analysis. In the latter case, the difference between the universal value and cluster baryon fractions is less than the systematic uncertainties associated with

  15. Fractional Processes and Fractional-Order Signal Processing Techniques and Applications

    CERN Document Server

    Sheng, Hu; Qiu, TianShuang

    2012-01-01

    Fractional processes are widely found in science, technology and engineering systems. In Fractional Processes and Fractional-order Signal Processing, some complex random signals, characterized by the presence of a heavy-tailed distribution or non-negligible dependence between distant observations (local and long memory), are introduced and examined from the ‘fractional’ perspective using simulation, fractional-order modeling and filtering and realization of fractional-order systems. These fractional-order signal processing (FOSP) techniques are based on fractional calculus, the fractional Fourier transform and fractional lower-order moments. Fractional Processes and Fractional-order Signal Processing: • presents fractional processes of fixed, variable and distributed order studied as the output of fractional-order differential systems; • introduces FOSP techniques and the fractional signals and fractional systems point of view; • details real-world-application examples of FOSP techniques to demonstr...

  16. The radiosurgery fractionation quandary: single fraction or hypofractionation?

    Science.gov (United States)

    Kirkpatrick, John P; Soltys, Scott G; Lo, Simon S; Beal, Kathryn; Shrieve, Dennis C; Brown, Paul D

    2017-04-01

    Stereotactic radiosurgery (SRS), typically administered in a single session, is widely employed to safely, efficiently, and effectively treat small intracranial lesions. However, for large lesions or those in close proximity to critical structures, it can be difficult to obtain an acceptable balance of tumor control while avoiding damage to normal tissue when single-fraction SRS is utilized. Treating a lesion in 2 to 5 fractions of SRS (termed "hypofractionated SRS" [HF-SRS]) potentially provides the ability to treat a lesion with a total dose of radiation that provides both adequate tumor control and acceptable toxicity. Indeed, studies of HF-SRS in large brain metastases, vestibular schwannomas, meningiomas, and gliomas suggest that a superior balance of tumor control and toxicity is observed compared with single-fraction SRS. Nonetheless, a great deal of effort remains to understand radiobiologic mechanisms for HF-SRS driving the dose-volume response relationship for tumors and normal tissues and to utilize this fundamental knowledge and the results of clinic studies to optimize HF-SRS. In particular, the application of HF-SRS in the setting of immunomodulatory cancer therapies offers special challenges and opportunities.

  17. Improving Children's Knowledge of Fraction Magnitudes

    Science.gov (United States)

    Fazio, Lisa K.; Kennedy, Casey A.; Siegler, Robert S.

    2016-01-01

    We examined whether playing a computerized fraction game, based on the integrated theory of numerical development and on the Common Core State Standards' suggestions for teaching fractions, would improve children's fraction magnitude understanding. Fourth and fifth-graders were given brief instruction about unit fractions and played "Catch…

  18. Green's Theorem for Generalized Fractional Derivatives

    CERN Document Server

    Odzijewicz, Tatiana; Torres, Delfim F M

    2012-01-01

    We study three types of generalized partial fractional operators. An extension of Green's theorem, by considering partial fractional derivatives with more general kernels, is proved. New results are obtained, even in the particular case when the generalized operators are reduced to the standard partial fractional derivatives and fractional integrals in the sense of Riemann-Liouville or Caputo.

  19. Using Number Sense to Compare Fractions

    Science.gov (United States)

    Bray, Wendy S.; Abreu-Sanchez, Laura

    2010-01-01

    One mathematical focus for third graders is to develop deep understanding of fractions and fraction equivalence, including comparing fractions through use of models and reasoning strategies. Before reading further, consider how you might solve the following problem: Which fraction is greater, 14/24 or 17/36? The initial impulse of many adults is…

  20. 'The mother of all continued fractions'

    NARCIS (Netherlands)

    Dajani, K.; Kraaikamp, C.

    2001-01-01

    In this paper we give the relationship between the regular continued fraction and the Lehner fractions using a procedure known as insertion Starting from the regular continued fraction expansion of any real irrational x when the maximal number of insertions is applied one obtains the Lehner fraction

  1. 9 CFR 113.7 - Multiple fractions.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Multiple fractions. 113.7 Section 113... § 113.7 Multiple fractions. (a) When a biological product contains more than one immunogenic fraction, the completed product shall be evaluated by tests applicable to each fraction. (b) When...

  2. Evaluating fractionated space systems - Status

    Science.gov (United States)

    Cornford, S.; Jenkins, S.; Wall, S.; Cole, B.; Bairstow, B.; Rouquette, N.; Dubos, G.; Ryan, T.; Zarifian, P.; Boutwell, J.

    DARPA has funded a number of teams to further refine its Fractionated Spacecraft vision. Several teams, including this team led by JPL, have been tasked to develop a tool for the evaluation of the Business case for a fractionated system architecture. This evaluation is to understand under what conditions and constraints the fractionated architecture make more sense (in a cost/benefit sense) than the traditional monolithic paradigm. Our approach to this evaluation is to generate and evaluate a variety of trade space options. These options include various sets of stimuli, various degrees of fractionation and various subsystem element properties. The stimuli include many not normally modeled such as technology obsolescence, funding profile changes and changes in mission objectives during the mission itself. The degrees of fractionation enable various traditional subsystem elements to be distributed across different free flyers which then act in concert as needed. This will enable key technologies to be updated as need dictates and availability allows. We have described our approach in a previous IEEE Aerospace conference paper but will briefly summarize here. Our approach to generate the Business Case evaluation is to explicitly model both the implementation and operation phases for the life cycle of a fractionated constellation. A variety of models are integrated into the Phoenix ModelCenter framework and are used to generate various intermediate data which is aggregated into the Present Strategic Value (PSV). The PSV is essentially the value (including the value of the embedded real options) minus the cost. These PSVs are calculated for a variety of configurations and scenarios including variations of various stimuli or uncertainties (e.g. supply chain delays, launch vehicle failures and orbital debris events). There are various decision options (e.g. delay, accelerate, cancel) which can now be exercised for each stimulus. We can compute the PSV for the various comb

  3. Fractional conservation laws in optimal control theory

    CERN Document Server

    Frederico, Gastao S F

    2007-01-01

    Using the recent formulation of Noether's theorem for the problems of the calculus of variations with fractional derivatives, the Lagrange multiplier technique, and the fractional Euler-Lagrange equations, we prove a Noether-like theorem to the more general context of the fractional optimal control. As a corollary, it follows that in the fractional case the autonomous Hamiltonian does not define anymore a conservation law. Instead, it is proved that the fractional conservation law adds to the Hamiltonian a new term which depends on the fractional-order of differentiation, the generalized momentum, and the fractional derivative of the state variable.

  4. Fractional Authorship in Nuclear Physics

    CERN Document Server

    Pritychenko, B

    2015-01-01

    Large, multi-institutional groups or collaborations of scientists are engaged in nuclear physics research projects, and the number of research facilities is dwindling. These collaborations have their own authorship rules, and they produce a large number of highly-cited papers. Multiple authorship of nuclear physics publications creates a problem with the assessment of an individual author's productivity relative to his/her colleagues and renders ineffective a performance metrics solely based on annual publication and citation counts. Many institutions are increasingly relying on the total number of first-author papers; however, this approach becomes counterproductive for large research collaborations with an alphabetical order of authors. A concept of fractional authorship (the claiming of credit for authorship by more than one individual) helps to clarify this issue by providing a more complete picture of research activities. In the present work, nuclear physics fractional and total authorships have been inv...

  5. Nitrogen fractionation in Titan's aerosols

    Science.gov (United States)

    Carrasco, Nathalie; Kuga, Maia; Marty, Bernard; Fleury, Benjamin; Marrocchi, Yves

    2016-06-01

    A strong nitrogen fractionation is found by Cassini in Titan's atmosphere with the detection of 15N-rich HCN relative to N2. Photodissociation of N2 associated or not to self-shielding might involve 15N-rich radicals prone to incorporation into forming organics. However the isotopic composition is only available for very simple gaseous N-bearing compounds, and the propagation and conservation of such a large N-isotopic fractionation upon polymerization is actually out of reach with the instruments onboard Cassini. We will therefore present a first laboratory investigation of the possible enrichment in the solid organic aerosols. We will also discuss the space instrumention required in the future to answer this pending issue on Titan.

  6. Astrophysical Applications of Fractional Calculus

    Science.gov (United States)

    Stanislavsky, Aleksander A.

    The paradigm of fractional calculus occupies an important place for the macroscopic description of subdiffusion. Its advance in theoretical astrophysics is expected to be very attractive too. In this report we discuss a recent development of the idea to some astrophysical problems. One of them is connected with a random migration of bright points associated with magnetic fields at the solar photosphere. The transport of the bright points has subdiffusive features that require the fractional generalization of the Leighton's model. Another problem is related to the angular distribution of radio beams, being propagated through a medium with random inhomogeneities. The peculiarity of this medium is that radio beams are trapped because of random wave localization. This idea can be useful for the diagnostics of interplanetary and interstellar turbulent media.

  7. Geometrical explanation of the fractional complex transform and derivative chain rule for fractional calculus

    Energy Technology Data Exchange (ETDEWEB)

    He, Ji-Huan, E-mail: hejihuan@suda.edu.cn [National Engineering Laboratory for Modern Silk, College of Textile and Engineering, Soochow University, 199 Ren-ai Road, Suzhou 215123 (China); Elagan, S.K., E-mail: sayed_khalil2000@yahoo.com [Mathematics and Statistics Department, Faculty of Science, Taif University, P.O. 888 (Saudi Arabia); Department of Mathematics, Faculty of Science, Menofiya University, Shebin Elkom (Egypt); Li, Z.B., E-mail: zhengbiaoli@l26.com [College of Mathematics and Information Science, Qujing Normal University, Qujing, Yunnan 655011 (China)

    2012-01-09

    The fractional complex transform is suggested to convert a fractional differential equation with Jumarie's modification of Riemann–Liouville derivative into its classical differential partner. Understanding the fractional complex transform and the chain rule for fractional calculus are elucidated geometrically. -- Highlights: ► The chain rule for fractional calculus is invalid, a counter example is given. ► The fractional complex transform is explained geometrically. ► Fractional equations can be converted into differential equations.

  8. Fractional-calculus diffusion equation

    OpenAIRE

    Ajlouni, Abdul-Wali MS; Al-Rabai'ah, Hussam A

    2010-01-01

    Background Sequel to the work on the quantization of nonconservative systems using fractional calculus and quantization of a system with Brownian motion, which aims to consider the dissipation effects in quantum-mechanical description of microscale systems. Results The canonical quantization of a system represented classically by one-dimensional Fick's law, and the diffusion equation is carried out according to the Dirac method. A suitable Lagrangian, and Hamiltonian, describing the diffusive...

  9. Fractional statistical potential in graphene

    Science.gov (United States)

    Ardenghi, J. S.

    2017-03-01

    In this work the fractional statistics is applied to an anyon gas in graphene to obtain the special features that the arbitrary phase interchange of the particle coordinates introduce in the thermodynamic properties. The electron gas is constituted by N anyons in the long wavelength approximation obeying fractional exclusion statistics and the partition function is analyzed in terms of a perturbation expansion up to first order in the dimensionless constant λ / L being L the length of the graphene sheet and λ = βℏvF the thermal wavelength. By considering the correct permutation expansion of the many-anyons wavefunction, taking into account that the phase changes with the number of inversions in each permutation, the statistical fermionic/bosonic potential is obtained and the intermediate statistical behavior is found. It is shown that "extra" fermonic and bosonic particles states appears and this "statistical particle" distribution depends on N. Entropy and specific heat is obtained up to first order in λ / L showing that the results obtained differs from those obtained in different approximation to the fractional exclusion statistics.

  10. Symmetry fractionalization and twist defects

    Science.gov (United States)

    Tarantino, Nicolas; Lindner, Netanel H.; Fidkowski, Lukasz

    2016-03-01

    Topological order in two-dimensions can be described in terms of deconfined quasiparticle excitations—anyons—and their braiding statistics. However, it has recently been realized that this data does not completely describe the situation in the presence of an unbroken global symmetry. In this case, there can be multiple distinct quantum phases with the same anyons and statistics, but with different patterns of symmetry fractionalization—termed symmetry enriched topological order. When the global symmetry group G, which we take to be discrete, does not change topological superselection sectors—i.e. does not change one type of anyon into a different type of anyon—one can imagine a local version of the action of G around each anyon. This leads to projective representations and a group cohomology description of symmetry fractionalization, with the second cohomology group {H}2(G,{{ A }}{{abelian}}) being the relevant group. In this paper, we treat the general case of a symmetry group G possibly permuting anyon types. We show that despite the lack of a local action of G, one can still make sense of a so-called twisted group cohomology description of symmetry fractionalization, and show how this data is encoded in the associativity of fusion rules of the extrinsic ‘twist’ defects of the symmetry. Furthermore, building on work of Hermele (2014 Phys. Rev. B 90 184418), we construct a wide class of exactly-solvable models which exhibit this twisted symmetry fractionalization, and connect them to our formal framework.

  11. Lipopolysaccharides from Serratia marcescens possess one or two 4-amino-4-deoxy-L-arabinopyranose 1-phosphate residues in the lipid A and D-glycero-D-talo-oct-2-ulopyranosonic acid in the inner core region.

    Science.gov (United States)

    Vinogradov, Evgeny; Lindner, Buko; Seltmann, Guntram; Radziejewska-Lebrecht, Joanna; Holst, Otto

    2006-08-25

    The carbohydrate backbones of the core-lipid A region were characterized from the lipopolysaccharides (LPSs) of Serratia marcescens strains 111R (a rough mutant strain of serotype O29) and IFO 3735 (a smooth strain not serologically characterized but possessing the O-chain structure of serotype O19). The LPSs were degraded either by mild hydrazinolysis (de-O-acylation) and hot 4 M KOH (de-N-acylation), or by hydrolysis in 2 % aqueous acetic acid, or by deamination. Oligosaccharide phosphates were isolated by high-performance anion-exchange chromatography. Through the use of compositional analysis, electrospray ionization Fourier transform mass spectrometry, and 1H and 13C NMR spectroscopy applying various one- and two-dimensional experiments, we identified the structures of the carbohydrate backbones that contained D-glycero-D-talo-oct-2-ulopyranosonic acid and 4-amino-4-deoxy-L-arabinose 1-phosphate residues. We also identified some truncated structures for both strains. All sugars were D-configured pyranoses and alpha-linked, except where stated otherwise.

  12. Screening and identification of Serratia marcescens high-producing prodigiosin%一株高产灵菌红素粘质沙雷氏菌的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    韦凤; 蒋冬花; 蔡琪敏; 宋迤明

    2011-01-01

    A red pigment producing bacterial strain was screened from a freshwater fish body through isolating color bacteria in nature. This strain was identified as Serratia marcescens based on morphological, physiological characters and 16S rDNA gene sequence. This pigment was demonstrated belong to prodigiosin on the basis of UV spectrum and TLC. The yield of crude prodigiosin reached at 475 mg/L.%通过筛选自然生境中的产色素菌株,从淡水鱼体中分离得到一株高产红色色素的Sm-128菌株.经形态观察、生理生化实验和16S rDNA基因序列分析,鉴定Sm-128菌株为粘质沙雷氏菌(Serratia marcescens).结合紫外吸收光谱及薄层色谱分析,证实Sm-128菌株所产色素为灵菌红素,粗品产量达475 mg/L.

  13. Potentiation of the synergistic activities of chitinases ChiA, ChiB and ChiC from Serratia marcescens CFFSUR-B2 by chitobiase (Chb) and chitin binding protein (CBP).

    Science.gov (United States)

    Gutiérrez-Román, Martha Ingrid; Dunn, Michael F; Tinoco-Valencia, Raunel; Holguín-Meléndez, Francisco; Huerta-Palacios, Graciela; Guillén-Navarro, Karina

    2014-01-01

    With the goal of understanding the chitinolytic mechanism of the potential biological control strain Serratia marcescens CFFSUR-B2, genes encoding chitinases ChiA, ChiB and ChiC, chitobiase (Chb) and chitin binding protein (CBP) were cloned, the protein products overexpressed in Escherichia coli as 6His-Sumo fusion proteins and purified by affinity chromatography. Following affinity tag removal, the chitinolytic activity of the recombinant proteins was evaluated individually and in combination using colloidal chitin as substrate. ChiB and ChiC were highly active while ChiA was inactive. Reactions containing both ChiB and ChiC showed significantly increased N-acetylglucosamine trimer and dimer formation, but decreased monomer formation, compared to reactions with either enzyme alone. This suggests that while both ChiB and ChiC have a general affinity for the same substrate, they attack different sites and together degrade chitin more efficiently than either enzyme separately. Chb and CBP in combination with ChiB and ChiC (individually or together) increased their chitinase activity. We report for the first time the potentiating effect of Chb on the activity of the chitinases and the synergistic activity of a mixture of all five proteins (the three chitinases, Chb and CBP). These results contribute to our understanding of the mechanism of action of the chitinases produced by strain CFFSUR-B2 and provide a molecular basis for its high potential as a biocontrol agent against fungal pathogens.

  14. On fractional Langevin equation involving two fractional orders

    Science.gov (United States)

    Baghani, Omid

    2017-01-01

    In numerical analysis, it is frequently needed to examine how far a numerical solution is from the exact one. To investigate this issue quantitatively, we need a tool to measure the difference between them and obviously this task is accomplished by the aid of an appropriate norm on a certain space of functions. For example, Sobolev spaces are indispensable part of theoretical analysis of partial differential equations and boundary integral equations, as well as are necessary for the analysis of some numerical methods for the solving of such equations. But most of articles that appear in this field usually use ‖.‖∞ in the space of C[a, b] which is very restrictive. In this paper, we introduce a new norm that is convenient for the fractional and singular differential equations. Using this norm, the existence and uniqueness of initial value problems for nonlinear Langevin equation with two different fractional orders are studied. In fact, the obtained results could be used for the classical cases. Finally, by two examples we show that we cannot always speak about the existence and uniqueness of solutions just by using the previous methods.

  15. Conformable Fractional Nikiforov—Uvarov Method

    Science.gov (United States)

    Karayer, H.; Demirhan, D.; Büyükkılıç, F.

    2016-07-01

    We introduce conformable fractional Nikiforov—Uvarov (NU) method by means of conformable fractional derivative which is the most natural definition in non-integer calculus. Since, NU method gives exact eigenstate solutions of Schrödinger equation (SE) for certain potentials in quantum mechanics, this method is carried into the domain of fractional calculus to obtain the solutions of fractional SE. In order to demonstrate the applicability of the conformable fractional NU method, we solve fractional SE for harmonic oscillator potential, Woods—Saxon potential, and Hulthen potential.

  16. Fractional vortex dipole phase filter

    Science.gov (United States)

    Sharma, Manoj Kumar; Joseph, Joby; Senthilkumaran, Paramasivam

    2014-10-01

    In spatial filtering experiments, the use of vortex phase filters plays an important role in realizing isotropic edge enhancement. In this paper, we report the use of a vortex dipole phase filter in spatial filtering. A dipole made of fractional vortices is used, and its filtering characteristics are studied. It is observed that the filter performance can be tuned by varying the distance of separation between the vortices of the dipole to achieve better contrast and output noise suppression, and when this distance tends to infinity, the filter performs like a 1-D Hilbert mask. Experimental and simulation results are presented.

  17. Fractional Trajectories: Decorrelation Versus Friction

    Science.gov (United States)

    2013-07-27

    function, andmoving back to the time domain yields the fractional trajectory V(t) = Eα(Otα)V(0). (4) Note that the Mittag-Leffler function is defined...bxy) ∂ ∂x − (cy − δxy) ∂ ∂y , (35) with the vector V having the components x and y. The predictor– corrector integration method is adopted to solve...Using the predictor– corrector method with α = 1 we numerically integrate the system of differential equations to find the operational time trajectory

  18. Reconstructing past fractional record values

    Directory of Open Access Journals (Sweden)

    Magdy E. El-Adll

    2016-10-01

    Full Text Available In this paper, reconstructing past fractional upper (lower records from any absolutely continuous distribution is proposed. For this purpose, two pivotal quantities are given and their exact distributions are derived. More detailed results, including the case of unknown parameters, are given for the exponential and Fre´chet distributions. Moreover, the exact mean square reconstructor errors are obtained and some comparisons between the pivotal quantities are performed. To explore the efficiency of the obtained results, a simulation study is conducted and two real data sets are analyzed.

  19. Fractional Moments on Bandit Problems

    CERN Document Server

    B, Ananda Narayanan

    2012-01-01

    Reinforcement learning addresses the dilemma between exploration to find profitable actions and exploitation to act according to the best observations already made. Bandit problems are one such class of problems in stateless environments that represent this explore/exploit situation. We propose a learning algorithm for bandit problems based on fractional expectation of rewards acquired. The algorithm is theoretically shown to converge on an eta-optimal arm and achieve O(n) sample complexity. Experimental results show the algorithm incurs substantially lower regrets than parameter-optimized eta-greedy and SoftMax approaches and other low sample complexity state-of-the-art techniques.

  20. A Local Fractional Variational Iteration Method for Laplace Equation within Local Fractional Operators

    Directory of Open Access Journals (Sweden)

    Yong-Ju Yang

    2013-01-01

    Full Text Available The local fractional variational iteration method for local fractional Laplace equation is investigated in this paper. The operators are described in the sense of local fractional operators. The obtained results reveal that the method is very effective.

  1. Galaxy Cluster Baryon Fractions Revisited

    CERN Document Server

    Gonzalez, Anthony H; Zabludoff, Ann I; Zaritsky, Dennis

    2013-01-01

    We measure the baryons contained in both the stellar and hot gas components for twelve galaxy clusters and groups at z~0.1 with M=1-5e14 Msun. This paper improves upon our previous work through the addition of XMM data, enabling measurements of the total mass and masses of each major baryonic component --- ICM, intracluster stars, and stars in galaxies --- for each system. We recover a relation for the stellar mass versus halo mass consistent with our previous result. We confirm that the partitioning of baryons between the stellar and hot gas components is a strong function of M500; the fractions of total mass in stars and X-ray gas within r500 scale as M500^-0.45 and M500^0.26, respectively. We also confirm that the combination of the BCG and intracluster stars is an increasingly important contributor to the stellar baryon budget in lower halo masses. We find a weak, but statistically significant, dependence of the total baryon fraction upon halo mass, scaling as M500^0.16. For M500>2e14, the total baryon fr...

  2. Microfluidic Devices for Blood Fractionation

    Directory of Open Access Journals (Sweden)

    Chwee Teck Lim

    2011-07-01

    Full Text Available Blood, a complex biological fluid, comprises 45% cellular components suspended in protein rich plasma. These different hematologic components perform distinct functions in vivo and thus the ability to efficiently fractionate blood into its individual components has innumerable applications in both clinical diagnosis and biological research. Yet, processing blood is not trivial. In the past decade, a flurry of new microfluidic based technologies has emerged to address this compelling problem. Microfluidics is an attractive solution for this application leveraging its numerous advantages to process clinical blood samples. This paper reviews the various microfluidic approaches realized to successfully fractionate one or more blood components. Techniques to separate plasma from hematologic cellular components as well as isolating blood cells of interest including certain rare cells are discussed. Comparisons based on common separation metrics including efficiency (sensitivity, purity (selectivity, and throughput will be presented. Finally, we will provide insights into the challenges associated with blood-based separation systems towards realizing true point-of-care (POC devices and provide future perspectives.

  3. Continued fractions and heavy sequences

    CERN Document Server

    Boshernitzan, Michael

    2009-01-01

    We initiate the study of the sets $H(c)$, $0=x-[x]$ stands for the fractional part of $x\\in \\mathbb R$. We prove that, for rational $c$, the sets $H(c)$ are of positive Hausdorff dimension and, in particular, are uncountable. For integers $m\\geq1$, we obtain a surprising characterization of the numbers $\\alpha\\in H_m= H(\\frac1m)$ in terms of their continued fraction expansions: The odd entries (partial quotients) of these expansions are divisible by $m$. The characterization implies that $x\\in H_m$ if and only if $\\frac 1{mx} \\in H_m$, for $x>0$. We are unaware of a direct proof of this equivalence, without making a use of the mentioned characterization of the sets $H_m$. We also introduce the dual sets $\\hat H_m$ of reals $y$ for which the sequence of integers $\\big([ky]\\big)_{k\\geq1}$ consistently hits the set $m\\mathbb Z$ with the at least expected frequency $\\frac1m$ and establish the connection with the sets $H_m$: {2mm} If $xy=m$ for $x,y>0$, then $x\\in H_m$ if and only if $y\\in \\hat H_m$. The motivatio...

  4. Fractional baud-length coding

    Directory of Open Access Journals (Sweden)

    J. Vierinen

    2011-06-01

    Full Text Available We present a novel approach for modulating radar transmissions in order to improve target range and Doppler estimation accuracy. This is achieved by using non-uniform baud lengths. With this method it is possible to increase sub-baud range-resolution of phase coded radar measurements while maintaining a narrow transmission bandwidth. We first derive target backscatter amplitude estimation error covariance matrix for arbitrary targets when estimating backscatter in amplitude domain. We define target optimality and discuss different search strategies that can be used to find well performing transmission envelopes. We give several simulated examples of the method showing that fractional baud-length coding results in smaller estimation errors than conventional uniform baud length transmission codes when estimating the target backscatter amplitude at sub-baud range resolution. We also demonstrate the method in practice by analyzing the range resolved power of a low-altitude meteor trail echo that was measured using a fractional baud-length experiment with the EISCAT UHF system.

  5. Staircase and fractional part functions

    Science.gov (United States)

    Amram, Meirav; Dagan, Miriam; Ioshpe, Michael; Satianov, Pavel

    2016-10-01

    The staircase and fractional part functions are basic examples of real functions. They can be applied in several parts of mathematics, such as analysis, number theory, formulas for primes, and so on; in computer programming, the floor and ceiling functions are provided by a significant number of programming languages - they have some basic uses in various programming tasks. In this paper, we view the staircase and fractional part functions as a classical example of non-continuous real functions. We introduce some of their basic properties, present some interesting constructions concerning them, and explore some intriguing interpretations of such functions. Throughout the paper, we use these functions in order to explain basic concepts in a first calculus course, such as domain of definition, discontinuity, and oddness of functions. We also explain in detail how, after researching the properties of such functions, one can draw their graph; this is a crucial part in the process of understanding their nature. In the paper, we present some subjects that the first-year student in the exact sciences may not encounter. We try to clarify those subjects and show that such ideas are important in the understanding of non-continuous functions, as a part of studying analysis in general.

  6. Dean flow fractionation of chromosomes

    Science.gov (United States)

    Hockin, Matt; Sant, Himanshu J.; Capecchi, Mario; Gale, Bruce K.

    2016-03-01

    Efforts to transfer intact mammalian chromosomes between cells have been attempted for more than 50 years with the consistent result being transfer of sub unit length pieces regardless of method. Inertial microfluidics is a new field that has shown much promise in addressing the fractionation of particles in the 2-20 μm size range (with unknown limits) and separations are based upon particles being carried by curving confined flows (within a spiral shaped, often rectangular flow chamber) and migrating to stable "equilibrium" positions of varying distance from a chamber wall depending on the balance of dean and lift forces. We fabricated spiral channels for inertial microfluidic separations using a standard soft lithography process. The concentration of chromosomes, small contaminant DNA and large cell debris in each outlets were evaluated using microscope (60X) and a flow cytometer. Using Dean Flow Fractionation, we were able to focus 4.5 times more chromosomes in outlet 2 compared to outlet 4 where most of the large debris is found. We recover 16% of the chromosomes in outlet #1- 50% in 2, 23% in 3 and 11% in 4. It should be noted that these estimates of recovery do not capture one piece of information- it actually may be that the chromosomes at each outlet are physically different and work needs to be done to verify this potential.

  7. Multiple Interactive Representations for Fractions Learning

    NARCIS (Netherlands)

    Feenstra, Laurens; Aleven, Vincent; Rummel, Nikol; Taatgen, Niels; Aleven,; Kay, J; Mostow, J

    2010-01-01

    Multiple External Representations (MERs) have been used successfully in instructional activities, including fractions However, students often have difficulties making the connections between the MERs spontaneously We argue that interactive fraction representations may help students in discovering re

  8. Boundary Controllability of Nonlinear Fractional Integrodifferential Systems

    Directory of Open Access Journals (Sweden)

    Ahmed HamdyM

    2010-01-01

    Full Text Available Sufficient conditions for boundary controllability of nonlinear fractional integrodifferential systems in Banach space are established. The results are obtained by using fixed point theorems. We also give an application for integropartial differential equations of fractional order.

  9. Fractional Order Element Based Impedance Matching

    KAUST Repository

    Radwan, Ahmed Gomaa

    2014-06-24

    Disclosed are various embodiments of methods and systems related to fractional order element based impedance matching. In one embodiment, a method includes aligning a traditional Smith chart (|.alpha.|=1) with a fractional order Smith chart (|.alpha.|.noteq.1). A load impedance is located on the traditional Smith chart and projected onto the fractional order Smith chart. A fractional order matching element is determined by transitioning along a matching circle of the fractional order Smith chart based at least in part upon characteristic line impedance. In another embodiment, a system includes a fractional order impedance matching application executed in a computing device. The fractional order impedance matching application includes logic that obtains a first set of Smith chart coordinates at a first order, determines a second set of Smith chart coordinates at a second order, and determines a fractional order matching element from the second set of Smith chart coordinates.

  10. Fractional Smoothness of Some Stochastic Integrals

    Institute of Scientific and Technical Information of China (English)

    Peng XIE; Xi Cheng ZHANG

    2007-01-01

    We study the fractional smoothness in the sense of Malliavin calculus of stochastic integralsof the form ∫10 φ(Xs)d Xs,where Xs is a semimartingale and φ belongs to some fractional Sobolev spaceover R.

  11. The multiple-parameter fractional Fourier transform

    Institute of Scientific and Technical Information of China (English)

    LANG Jun; TAO Ran; RAN QiWen; WANG Yue

    2008-01-01

    The fractional Fourier transform (FRFT) has multiplicity, which is intrinsic in frac-tional operator. A new source for the multiplicity of the weight-type fractional Fou-rier transform (WFRFT) is proposed, which can generalize the weight coefficients of WFRFT to contain two vector parameters MN,∈ZM. Therefore a generalized frac-tional Fourier transform can be defined, which is denoted by the multiple-parameter fractional Fourier transform (MPFRFT). It enlarges the multiplicity of the FRFT, which not only includes the conventional FRFT and general multi-fractional Fourier transform as special cases, but also introduces new fractional Fourier transforms. It provides a unified framework for the FRFT, and the method is also available for fractionalizing other linear operators. In addition, numerical simulations of the MPFRFT on the Hermite-Gaussian and rectangular functions have been performed as a simple application of MPFRFT to signal processing.

  12. A fractional model for dye removal

    Directory of Open Access Journals (Sweden)

    Ji-Huan He

    2016-01-01

    Full Text Available The adsorption process has a fractional property, and a fractional model is suggested to study a transport model of direct textile industry wastewater. An approximate solution of the concentration is obtained by the variational iteration method.

  13. Fractional Transforms in Optical Information Processing

    Directory of Open Access Journals (Sweden)

    Maria Luisa Calvo

    2005-06-01

    Full Text Available We review the progress achieved in optical information processing during the last decade by applying fractional linear integral transforms. The fractional Fourier transform and its applications for phase retrieval, beam characterization, space-variant pattern recognition, adaptive filter design, encryption, watermarking, and so forth is discussed in detail. A general algorithm for the fractionalization of linear cyclic integral transforms is introduced and it is shown that they can be fractionalized in an infinite number of ways. Basic properties of fractional cyclic transforms are considered. The implementation of some fractional transforms in optics, such as fractional Hankel, sine, cosine, Hartley, and Hilbert transforms, is discussed. New horizons of the application of fractional transforms for optical information processing are underlined.

  14. Langevin equation with two fractional orders

    Energy Technology Data Exchange (ETDEWEB)

    Lim, S.C. [Faculty of Engineering, Multimedia University, Jalan Multimedia, Cyberjaya 63100, Selangor Darul Ehsan (Malaysia)], E-mail: sclim@mmu.edu.my; Li Ming [School of Information Science and Technology, East China Normal University, No. 500, Dong-Chuan Road, Shanghai 200241 (China)], E-mail: mli@ee.ecnu.edu.cn; Teo, L.P. [Faculty of Information Technology, Multimedia University, Jalan Multimedia, Cyberjaya 63100, Selangor Darul Ehsan (Malaysia)], E-mail: lpteo@mmu.edu.my

    2008-10-13

    A new type of fractional Langevin equation of two different orders is introduced. The solutions for this equation, known as the fractional Ornstein-Uhlenbeck processes, based on Weyl and Riemann-Liouville fractional derivatives are obtained. The basic properties of these processes are studied. An example of the spectral density of ocean wind speed which has similar spectral density as that of Weyl fractional Ornstein-Uhlenbeck process is given.

  15. Transcendental $p$-adic continued fractions

    OpenAIRE

    Ooto, Tomohiro

    2014-01-01

    We establish a new transcendence criterion of $p$-adic continued fractions which are called Ruban continued fractions. By this result, we give explicit transcendental Ruban continued fractions with bounded $p$-adic absolute value of partial quotients. This is $p$-adic analogy of Baker's result. We also prove that $p$-adic analogy of Lagrange Theorem for Ruban continued fractions is not true.

  16. Lyapunov functions for fractional order systems

    Science.gov (United States)

    Aguila-Camacho, Norelys; Duarte-Mermoud, Manuel A.; Gallegos, Javier A.

    2014-09-01

    A new lemma for the Caputo fractional derivatives, when 0<α<1, is proposed in this paper. This result has proved to be useful in order to apply the fractional-order extension of Lyapunov direct method, to demonstrate the stability of many fractional order systems, which can be nonlinear and time varying.

  17. An Alternative Starting Point for Fraction Instruction

    Science.gov (United States)

    Cortina, José Luis; Višnovská, Jana; Zúñiga, Claudia

    2015-01-01

    We analyze the results of a study conducted for the purpose of assessing the viability of an alternative starting point for teaching fractions. The alternative is based on Freudenthal's insights about fraction as comparison. It involves portraying the entities that unit fractions quantify as always being apart from the reference unit, instead of…

  18. Early Predictors of Middle School Fraction Knowledge

    Science.gov (United States)

    Bailey, Drew H.; Siegler, Robert S.; Geary, David C.

    2014-01-01

    Recent findings that earlier fraction knowledge predicts later mathematics achievement raise the question of what predicts later fraction knowledge. Analyses of longitudinal data indicated that whole number magnitude knowledge in first grade predicted knowledge of fraction magnitudes in middle school, controlling for whole number arithmetic…

  19. Stretching Student Teachers' Understanding of Fractions

    Science.gov (United States)

    Harvey, Roger

    2012-01-01

    The teaching of fractions in elementary school is known to be challenging. Literature indicates that teachers' and prospective teachers' lack of depth of fraction content knowledge and associated pedagogical knowledge is of concern. This study investigated the fraction content knowledge of prospective teachers and their ability to use that…

  20. Mathematical modelling of fractional order circuits

    CERN Document Server

    Moreles, Miguel Angel

    2016-01-01

    In this work a classical derivation of fractional order circuits models is presented. Generalized constitutive equations in terms of fractional Riemann-Liouville derivatives are introduced in the Maxwell's equations. Next the Kirchhoff voltage law is applied in a RCL circuit configuration. A fractional differential equation model is obtained with Caputo derivatives. Thus standard initial conditions apply.

  1. Stretching Student Teachers' Understanding of Fractions

    Science.gov (United States)

    Harvey, Roger

    2012-01-01

    The teaching of fractions in elementary school is known to be challenging. Literature indicates that teachers' and prospective teachers' lack of depth of fraction content knowledge and associated pedagogical knowledge is of concern. This study investigated the fraction content knowledge of prospective teachers and their ability to use that…

  2. Take a Bite out of Fraction Division

    Science.gov (United States)

    Cengiz, Nesrin; Rathouz, Margaret

    2011-01-01

    Division of fractions is often considered the most mechanical and least understood topic in elementary school. Enacting fraction division tasks in meaningful ways requires that teachers know not only "how" fraction division works but also "why" it works. The authors have created materials to help preservice teachers develop that knowledge. To…

  3. Preparing for Algebra by Building Fraction Sense

    Science.gov (United States)

    Rodrigues, Jessica; Dyson, Nancy I.; Hansen, Nicole; Jordan, Nancy C.

    2016-01-01

    Fractions are troublesome for many children, especially students with learning difficulties and disabilities in mathematics. To address this serious educational concern, this article recommends the use of number lines to build fraction sense. Math activities that center on the number line build fraction concepts as early as third grade. A number…

  4. The Richness of Children's Fraction Strategies

    Science.gov (United States)

    Kent, Laura B.; Empson, Susan B.; Nielsen, Lynne

    2015-01-01

    In this article, the authors discuss a special type of multiplication-and-division-of-fractions problem that elementary school teachers can use to promote children's understanding of fractional quantities and their relationships. These problems are accessible to students working at different levels of fraction understanding, and they can be solved…

  5. Continued fractions and the second Kepler law

    OpenAIRE

    Karpenkov, Oleg

    2009-01-01

    In this paper we introduce a link between geometry of ordinary continued fractions and trajectories of points that moves according to the second Kepler law. We expand geometric interpretation of ordinary continued fractions to the case of continued fractions with arbitrary elements.

  6. Identifying Fractions on a Number Line

    Science.gov (United States)

    Wong, Monica

    2013-01-01

    Fractions are generally introduced to students using the part--whole model. Yet the number line is another important representation which can be used to build fraction concepts (Australian Curriculum Assessment and Reporting Authority [ACARA], 2012). Number lines are recognised as key in students' number development not only of fractions, but…

  7. 16 CFR 500.17 - Fractions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Fractions. 500.17 Section 500.17 Commercial... LABELING ACT § 500.17 Fractions. (a) SI metric declarations of net quantity of contents of any consumer commodity may contain only decimal fractions. Other declarations of net quantity of contents may...

  8. Locating Fractions on a Number Line

    Science.gov (United States)

    Wong, Monica

    2013-01-01

    Understanding fractions remains problematic for many students. The use of the number line aids in this understanding, but requires students to recognise that a fraction represents the distance from zero to a dot or arrow marked on a number line which is a linear scale. This article continues the discussion from "Identifying Fractions on a…

  9. Teaching Fractions. Educational Practices Series-22

    Science.gov (United States)

    Fazio, Lisa; Siegler, Robert

    2011-01-01

    Students around the world have difficulties in learning about fractions. In many countries, the average student never gains a conceptual knowledge of fractions. This research guide provides suggestions for teachers and administrators looking to improve fraction instruction in their classrooms or schools. The recommendations are based on a…

  10. 12 CFR 5.67 - Fractional shares.

    Science.gov (United States)

    2010-01-01

    ... fractional shares. The bank may: (a) Issue scripts or warrants for trading; (b) Make reasonable arrangements... fair price upon the fraction not being issued through its sale, or the purchase of the additional... such stock is available; or (d) Sell full shares representing all the fractions at public auction, or...

  11. Natural fractionation of uranium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Noordmann, Janine

    2015-01-24

    The topic of this thesis was the investigation of U (n({sup 238}U) / n({sup 235}U)) isotope variations in nature with a focus on samples (1) that represent the continental crust and its weathering products (i.e. granites, shales and river water) (2) that represent products of hydrothermal alteration on mid-ocean ridges (i.e. altered basalts, carbonate veins and hydrothermal water) and (3) from restricted euxinic basins (i.e. from the water column and respective sediments). The overall goal was to explore the environmental conditions and unravel the mechanisms that fractionate the two most abundant U isotopes, n({sup 238}U) and n({sup 235}U), on Earth.

  12. Superconducting wires and fractional flux

    Science.gov (United States)

    Sá de Melo, C. A. R.

    1996-05-01

    The quantization of flux quanta in superconductors is revisited and analyzed in a new geometry. The system analyzed is a superconducting wire. The geometry is such that the superconducting wire winds N times around an insulating cylinder and that the wire has its end connected back to its beginning, thus producing an N-loop short circuited solenoid. The winding number N acts as a topological index that controls flux quantization. In this case, fractional flux quanta can be measured through the center of the insulating cylinder, provided that the cylinder radius is small enough. The Little-Parks experiment for an identical geometry is discussed. The period of oscillation of the transition temperature of the wire is found to vary as 1/N in units of flux Φ relative to the flux quantum Φ0. When a SQUID is made in such a geometry the maximal current through the SQUID varies with period Φ0/N.

  13. Subordination Pathways to Fractional Diffusion

    CERN Document Server

    Gorenflo, Rudolf; 10.1140/epjst/e2011-01386-2

    2011-01-01

    The uncoupled Continuous Time Random Walk (CTRW) in one space-dimension and under power law regime is splitted into three distinct random walks: (rw_1), a random walk along the line of natural time, happening in operational time; (rw_2), a random walk along the line of space, happening in operational time;(rw_3), the inversion of (rw_1), namely a random walk along the line of operational time, happening in natural time. Via the general integral equation of CTRW and appropriate rescaling, the transition to the diffusion limit is carried out for each of these three random walks. Combining the limits of (rw_1) and (rw_2) we get the method of parametric subordination for generating particle paths, whereas combination of (rw_2) and (rw_3) yields the subordination integral for the sojourn probability density in space-time fractional diffusion.

  14. Fractional Action Cosmology with Variable Order Parameter

    Science.gov (United States)

    El-Nabulsi, Rami Ahmad

    2017-04-01

    Fractional action cosmology with variable order parameter was constructed in this paper. Starting from a fractional weighted action which generalizes the fractional actionlike variational approach, a large number of cosmological dynamical equations are obtained depending on the mathematical type of the fractional order parameter. Through this paper, we selected two independent types which result on a number of cosmological scenarios and we discussed their dynamical consequences. It was observed that the present fractional cosmological formalism holds a large family of solutions and offers new features not found in the standard formalism and in many fundamental research papers.

  15. Correlation Structure of Fractional Pearson Diffusions.

    Science.gov (United States)

    Leonenko, Nikolai N; Meerschaert, Mark M; Sikorskii, Alla

    2013-09-01

    The stochastic solution to a diffusion equations with polynomial coefficients is called a Pearson diffusion. If the first time derivative is replaced by a Caputo fractional derivative of order less than one, the stochastic solution is called a fractional Pearson diffusion. This paper develops an explicit formula for the covariance function of a fractional Pearson diffusion in steady state, in terms of Mittag-Leffler functions. That formula shows that fractional Pearson diffusions are long range dependent, with a correlation that falls off like a power law, whose exponent equals the order of the fractional derivative.

  16. On the Definitions of Nabla Fractional Operators

    Directory of Open Access Journals (Sweden)

    Thabet Abdeljawad

    2012-01-01

    properties of the one operator by using the known properties of the other. We illustrate this idea with proving power rule and commutative property of discrete fractional sum operators. We also introduce and prove summation by parts formulas for the right and left fractional sum and difference operators, where we employ the Riemann-Liouville definition of the fractional difference. We formalize initial value problems for nonlinear fractional difference equations as an application of our findings. An alternative definition for the nabla right fractional difference operator is also introduced.

  17. Linearized asymptotic stability for fractional differential equations

    Directory of Open Access Journals (Sweden)

    Nguyen Cong

    2016-06-01

    Full Text Available We prove the theorem of linearized asymptotic stability for fractional differential equations. More precisely, we show that an equilibrium of a nonlinear Caputo fractional differential equation is asymptotically stable if its linearization at the equilibrium is asymptotically stable. As a consequence we extend Lyapunov's first method to fractional differential equations by proving that if the spectrum of the linearization is contained in the sector $\\{\\lambda \\in \\mathbb{C} : |\\arg \\lambda| > \\frac{\\alpha \\pi}{2}\\}$ where $\\alpha > 0$ denotes the order of the fractional differential equation, then the equilibrium of the nonlinear fractional differential equation is asymptotically stable.

  18. Laplace transform of fractional order differential equations

    Directory of Open Access Journals (Sweden)

    Song Liang

    2015-05-01

    Full Text Available In this article, we show that Laplace transform can be applied to fractional system. To this end, solutions of linear fractional-order equations are first derived by a direct method, without using Laplace transform. Then the solutions of fractional-order differential equations are estimated by employing Gronwall and Holder inequalities. They are showed be to of exponential order, which are necessary to apply the Laplace transform. Based on the estimates of solutions, the fractional-order and the integer-order derivatives of solutions are all estimated to be exponential order. As a result, the Laplace transform is proved to be valid in fractional equations.

  19. Fractional Action Cosmology with Variable Order Parameter

    Science.gov (United States)

    El-Nabulsi, Rami Ahmad

    2017-01-01

    Fractional action cosmology with variable order parameter was constructed in this paper. Starting from a fractional weighted action which generalizes the fractional actionlike variational approach, a large number of cosmological dynamical equations are obtained depending on the mathematical type of the fractional order parameter. Through this paper, we selected two independent types which result on a number of cosmological scenarios and we discussed their dynamical consequences. It was observed that the present fractional cosmological formalism holds a large family of solutions and offers new features not found in the standard formalism and in many fundamental research papers.

  20. Second Study of Hyper-Fractionated Radiotherapy

    Directory of Open Access Journals (Sweden)

    R. Jacob

    1999-01-01

    Full Text Available Purpose and Method. Hyper-fractionated radiotherapy for treatment of soft tissue sarcomas is designed to deliver a higher total dose of radiation without an increase in late normal tissue damage. In a previous study at the Royal Marsden Hospital, a total dose of 75 Gy using twice daily 1.25 Gy fractions resulted in a higher incidence of late damage than conventional radiotherapy using 2 Gy daily fractions treating to a total of 60 Gy. The current trial therefore used a lower dose per fraction of 1.2 Gy and lower total dose of 72 Gy, with 60 fractions given over a period of 6 weeks.

  1. Screening and Identification a Serratia marcescen Strain Producing Red-Pigment and Preliminary Study of the Fermentation Conditions%一株产灵菌红素粘质沙雷氏菌的筛选、鉴定及发酵条件

    Institute of Scientific and Technical Information of China (English)

    李子武; 张显; 徐美娟; 夏海锋; 饶志明

    2012-01-01

    A strain producing red-pigment was newly isolated under poor nutrition conditions. It was identified by 16S rDNA sequence and systematic analysis,as well as general morphological and biochemical characteristics,The results show that 16S rDNA sequence of the strain suggesting that the strain is Serratia marcescens Species. And it was named Serratia marcescens JNB5-1. The red-pigment was identified as prodigiosin by wavelength scanning and LC-MS. preliminary fermentation conditions of strain Serratia marcescens JNB5-1 was studied.The results showed that the yield of prodigiosin was improved to 4.139 g/L after 72 h in the medium:sucrose 2%,beef extract 1.5%, CaCl2 1%,proline 0.75%,MgSO4-7HIO 0.02%,FeSO4-7H2O 0.006%.%利用贫营养条件,从土壤样品中筛选到一株产红色素的菌株.经形态学、生理生化实验进行菌株初步鉴定,并经16S rDNA测序分析确定该菌株为粘质沙雷氏菌属,将其命名为:Serratia marcescens JNB5-1.该菌株所产红色素经全波长扫描及LC-MS确定为灵菌红素.对Serratia marcecens JNB5-1产灵菌红素做初步发酵研究,在蔗糖2g/dL,牛肉膏1.5 g/dL,CaCl21 g/dL,脯氨酸0.75 g/dL,MgSO4·7H2O 0.02 g/dL,FeSO4·7H2O 0.006 g/dL的培养基中发酵72 h后,其发酵产量可达4.139 g/L.

  2. 主动外排机制和膜蛋白缺失在粘质沙雷菌耐药中的研究∗%Study on the active efflux mechanism and the absence of membrane proteins in Serratia marcescens resistence

    Institute of Scientific and Technical Information of China (English)

    李欣; 汪建军; 任超杰; 扈会整; 王欣

    2015-01-01

    目的:研究粘质沙雷菌的耐药性与细胞的主动外排机制及细菌膜蛋白缺失相关性。方法:收集对亚胺培南和美罗培南耐药的粘质沙雷菌株15株,应用 PCR 扩增和 DNA 序列分析,采用 E 试验观察氰氯苯腙对亚胺培南最低抑菌浓度(MIC)的影响,以研究细胞内是否存在主动外排机制和膜蛋白缺失现象。结果:当 CCCP 存在时,其中7株粘质沙雷菌亚胺培南,美罗培南的MIC 值下降,提示存在主动外排机制。其中有1株 OprD2蛋白缺失,1株外排泵 MexB 基因阳性。结论:耐碳青霉烯类药物的粘质沙雷菌的耐药性与细胞的主动外排机制和膜蛋白缺失有关。%Objective:Study the drug resistance of Serratia marcescens whether related to the cells active efflux mechanism and the absence of bacterial membrane proteins or not.Methods:collected 1 5 strains Serratia marcescens that resist Imipenem and Meropenem ,application PCR amplification and DNA sequence analysis.adopt E test experiment observe the influence of CCCP for Imipenem minimal inhibitory concentration.in order to study intracellular was exist active efflux mechanism and the absence of membrane proteins or not.Results:When CCCP exist,there were 7 strains serratia marcescens for imipenem and Meropenem’MIC value decreased,prompting exist active efflux mechanism bacterial,and 1 strain absent OprD2 protein,1 strain efflux pump MexB gene positive.Con-clusion:The resistance of Serratia marcescens that resist Carbapenemase related to the cells active efflux mechanism and the absence of bacterial membrane proteins .

  3. Utilization of Different Corn Fractions by Broilers

    Directory of Open Access Journals (Sweden)

    SIFR Costa

    2015-09-01

    Full Text Available ABSTRACTThis study was conducted to evaluate the nutritional values of fractions of damaged corn. One hundred and eighty 22-d-old Cobb 500 male broilers were distributed in batteries according to a completely randomized design with six treatments of six replicates each. The treatments consisted of diets containing five corn fractions, classified as sound, fermented, insect-damaged, mold-damaged, or reference corn. The test diets consisted of 60% of reference diet + 40% of each corn fraction. Only the reference corn fraction included all the fractions at different proportions (0.8% fermented, 0.05% insect-damaged, 3.3% mold-damaged, and 95.85% sound grains. The method of total excreta collection was used to determine AMEn values and metabolizability coefficients of dry matter (MDM, crude protein (MCP, ether extract (MEE, and gross energy (MGE of the reference corn and its fractions. The density values of the corn fractions were used to calculate the correlations among the evaluated parameters. The evaluated corn fractions presented different compositions values. The insect-damaged and mold-damaged grains presented higher CP level, lower density, and MDM and MCP coefficients compared with the other fractions. However, calculated AMEn values were not significantly different (p>0.05 among corn fractions. A low correlation between density and AMEn content (r0.8 were calculated. Although the evaluated corn fractions presented different nutritional values, there were no marked differences in their utilization by broilers.

  4. Hydrologic transport and partitioning of phosphorus fractions

    Science.gov (United States)

    Berretta, C.; Sansalone, J.

    2011-06-01

    SummaryPhosphorus (P) in rainfall-runoff partitions between dissolved and particulate matter (PM) bound phases. This study investigates the transport and partitioning of P to PM fractions in runoff from a landscaped and biogenically-loaded carpark in Gainesville, FL (GNV). Additionally, partitioning and concentration results are compared to a similarly-sized concrete-paved source area of a similar rainfall depth frequency distribution in Baton Rouge, LA (BTR), where in contrast vehicular traffic represents the main source of pollutants. Results illustrate that concentrations of P fractions (dissolved, suspended, settleable and sediment) for GNV are one to two orders of magnitude higher than BTR. Despite these differences the dissolved fraction ( f d) and partitioning coefficient ( K d) distributions are similar, illustrating that P is predominantly bound to PM fractions. Examining PM size fractions, specific capacity for P (PSC) indicates that the P concentration order is suspended > settleable > sediment for GNV, similarly to BTR. For GNV the dominant PM mass fraction is sediment (>75 μm), while the mass of P is distributed predominantly between sediment and suspended (<25 μm) fractions since these PM mass fractions dominated the settleable one. With respect to transport of PM and P fractions the predominance of events for both areas is mass-limited first-flush, although each fraction illustrated unique washoff parameters. However, while transport is predominantly mass-limited, the transport of each PM and P fraction is influenced by separate hydrologic parameters.

  5. Fractional linear systems and electrical circuits

    CERN Document Server

    Kaczorek, Tadeusz

    2015-01-01

    This monograph covers some selected problems of positive and fractional electrical circuits composed of resistors, coils, capacitors and voltage (current) sources. The book consists of 8 chapters, 4 appendices and a list of references. Chapter 1 is devoted to fractional standard and positive continuous-time and discrete-time linear systems without and with delays. In chapter 2 the standard and positive fractional electrical circuits are considered and the fractional electrical circuits in transient states are analyzed.  Descriptor linear electrical circuits and their properties are investigated in chapter 3,  while chapter 4 is devoted to the stability of fractional standard and positive linear electrical circuits. The reachability, observability and reconstructability of fractional positive electrical circuits and their decoupling zeros are analyzed in chapter 5. The fractional linear electrical circuits with feedbacks are considered in chapter 6. In chapter 7 solutions of minimum energy control for standa...

  6. Solution of nonlinear space time fractional differential equations via the fractional projective Riccati expansion method

    CERN Document Server

    Abdel-Salam, Emad A-B; Hassan, Gmal F

    2015-01-01

    In this paper, the fractional projective Riccati expansion method is proposed to solve fractional differential equations. To illustrate the effectiveness of the method, we discuss the space-time fractional Burgers equation, the space-time fractional mKdV equation and time fractional biological population model. The solutions are expressed in terms of fractional hyperbolic functions. These solutions are useful to understand the mechanisms of the complicated nonlinear physical phenomena and fractional differential equations. Among these solutions, some are found for the first time. The fractal index for the obtained results is equal to one. Counter examples to compute the fractal index are introduced in appendix.

  7. Exact Solutions of Fractional Burgers and Cahn-Hilliard Equations Using Extended Fractional Riccati Expansion Method

    Directory of Open Access Journals (Sweden)

    Wei Li

    2014-01-01

    Full Text Available Based on a general fractional Riccati equation and with Jumarie’s modified Riemann-Liouville derivative to an extended fractional Riccati expansion method for solving the time fractional Burgers equation and the space-time fractional Cahn-Hilliard equation, the exact solutions expressed by the hyperbolic functions and trigonometric functions are obtained. The obtained results show that the presented method is effective and appropriate for solving nonlinear fractional differential equations.

  8. Wright functions governed by fractional directional derivatives and fractional advection diffusion equations

    CERN Document Server

    D'Ovidio, Mirko

    2012-01-01

    We consider fractional directional derivatives and establish some connection with stable densities. Solutions to advection equations involving fractional directional derivatives are presented and some properties investigated. In particular we obtain solutions written in terms of Wright functions by exploiting operational rules involving the shift operator. We also consider fractional advection diffusion equations involving fractional powers of the negative Laplace operator and directional derivatives of fractional order and discuss the probabilistic interpretations of solutions.

  9. Control and Synchronization of the Fractional-Order Lorenz Chaotic System via Fractional-Order Derivative

    Directory of Open Access Journals (Sweden)

    Ping Zhou

    2012-01-01

    Full Text Available The unstable equilibrium points of the fractional-order Lorenz chaotic system can be controlled via fractional-order derivative, and chaos synchronization for the fractional-order Lorenz chaotic system can be achieved via fractional-order derivative. The control and synchronization technique, based on stability theory of fractional-order systems, is simple and theoretically rigorous. The numerical simulations demonstrate the validity and feasibility of the proposed method.

  10. Control and Synchronization of the Fractional-Order Lorenz Chaotic System via Fractional-Order Derivative

    OpenAIRE

    Ping Zhou; Rui Ding

    2012-01-01

    The unstable equilibrium points of the fractional-order Lorenz chaotic system can be controlled via fractional-order derivative, and chaos synchronization for the fractional-order Lorenz chaotic system can be achieved via fractional-order derivative. The control and synchronization technique, based on stability theory of fractional-order systems, is simple and theoretically rigorous. The numerical simulations demonstrate the validity and feasibility of the proposed method.

  11. Hamiltonian chaos and fractional dynamics

    CERN Document Server

    Zaslavsky, George M

    2008-01-01

    The dynamics of realistic Hamiltonian systems has unusual microscopic features that are direct consequences of its fractional space-time structure and its phase space topology. The book deals with the fractality of the chaotic dynamics and kinetics, and also includes material on non-ergodic and non-well-mixing Hamiltonian dynamics. The book does not follow the traditional scheme of most of today's literature on chaos. The intention of the author has been to put together some of the most complex and yet open problems on the general theory of chaotic systems. The importance of the discussed issues and an understanding of their origin should inspire students and researchers to touch upon some of the deepest aspects of nonlinear dynamics. The book considers the basic principles of the Hamiltonian theory of chaos and some applications including for example, the cooling of particles and signals, control and erasing of chaos, polynomial complexity, Maxwell's Demon, and others. It presents a new and realistic image ...

  12. Water Fractions in Extrasolar Planetesimals

    CERN Document Server

    Jura, M

    2011-01-01

    With the goal of using externally-polluted white dwarfs to investigate the water fractions of extrasolar planetesimals, we assemble from the literature a sample that we estimate to be more than 60% complete of DB white dwarfs warmer than 13,000 K, more luminous than 3 ${\\times}$ 10$^{-3}$ L$_{\\odot}$ and within 80 pc of the Sun. When considering all the stars together, we find the summed mass accretion rate of heavy atoms exceeds that of hydrogen by over a factor of 1000. If so, this sub-population of extrasolar asteroids treated as an ensemble has little water and is at least a factor of 20 drier than CI chondrites, the most primitive meteorites. In contrast, while an apparent "excess" of oxygen in a single DB can be interpreted as evidence that the accreted material originated in a water-rich parent body, we show that at least in some cases, there can be sufficient uncertainties in the time history of the accretion rate that such an argument may be ambiguous. Regardless of the difficulty associated with int...

  13. Fractional ablative erbium YAG laser

    DEFF Research Database (Denmark)

    Taudorf, Elisabeth H; Haak, Christina S; Erlendsson, Andrés M

    2014-01-01

    BACKGROUND AND OBJECTIVES: Treatment of a variety of skin disorders with ablative fractional lasers (AFXL) is driving the development of portable AFXLs. This study measures micropore dimensions produced by a small 2,940 nm AFXL using a variety of stacked pulses, and determines a model correlating...... laser parameters with tissue effects. MATERIALS AND METHODS: Ex vivo pig skin was exposed to a miniaturized 2,940 nm AFXL, spot size 225 µm, density 5%, power levels 1.15-2.22 W, pulse durations 50-225 microseconds, pulse repetition rates 100-500 Hz, and 2, 20, or 50 stacked pulses, resulting in pulse...... 190 to 347 µm. CONCLUSIONS: Pulse stacking with a small, low power 2,940 nm AFXL created reproducible shallow to deep micropores, and influenced micropore configuration. Mathematical modeling established relations between laser settings and micropore dimensions, which assists in choosing laser...

  14. Dynamics with Low-Level Fractionality

    CERN Document Server

    Tarasov, V E; Tarasov, Vasily E.; Zaslavsky, George M.

    2005-01-01

    The notion of fractional dynamics is related to equations of motion with one or a few terms with derivatives of a fractional order. This type of equation appears in the description of chaotic dynamics, wave propagation in fractal media, and field theory. For the fractional linear oscillator the physical meaning of the derivative of order $\\alpha<2$ is dissipation. In systems with many spacially coupled elements (oscillators) the fractional derivative, along the space coordinate, corresponds to a long range interaction. We discuss a method of constructing a solution using an expansion in $\\epsilon=n-\\alpha$ with small $\\epsilon$ and positive integer $n$. The method is applied to the fractional linear and nonlinear oscillators and to fractional Ginzburg-Landau or parabolic equations.

  15. The fractional oscillator process with two indices

    Energy Technology Data Exchange (ETDEWEB)

    Lim, S C [Faculty of Engineering, Multimedia University, Jalan Multimedia, Cyberjaya 63100, Selangor Darul Ehsan (Malaysia); Teo, L P [Faculty of Information Technology, Multimedia University, Jalan Multimedia, Cyberjaya 63100, Selangor Darul Ehsan (Malaysia)], E-mail: sclim@mmu.edu.my, E-mail: lpteo@mmu.edu.my

    2009-02-13

    We introduce a new fractional oscillator process which can be obtained as a solution of a stochastic differential equation with two fractional orders. Basic properties such as fractal dimension and short-range dependence of the process are studied by considering the asymptotic properties of its covariance function. By considering the fractional oscillator process as the velocity of a diffusion process, we derive the corresponding diffusion constant, fluctuation-dissipation relation and mean-square displacement. The fractional oscillator process can also be regarded as a one-dimensional fractional Euclidean Klein-Gordon field, which can be obtained by applying the Parisi-Wu stochastic quantization method to a nonlocal Euclidean action. The Casimir energy associated with the fractional field at positive temperature is calculated by using the zeta function regularization technique.

  16. Review of Some Promising Fractional Physical Models

    CERN Document Server

    Tarasov, Vasily E

    2015-01-01

    Fractional dynamics is a field of study in physics and mechanics investigating the behavior of objects and systems that are characterized by power-law non-locality, power-law long-term memory or fractal properties by using integrations and differentiation of non-integer orders, i.e., by methods of the fractional calculus. This paper is a review of physical models that look very promising for future development of fractional dynamics. We suggest a short introduction to fractional calculus as a theory of integration and differentiation of non-integer order. Some applications of integro-differentiations of fractional orders in physics are discussed. Models of discrete systems with memory, lattice with long-range inter-particle interaction, dynamics of fractal media are presented. Quantum analogs of fractional derivatives and model of open nano-system systems with memory are also discussed.

  17. Fractional RC and LC Electrical Circuits

    Directory of Open Access Journals (Sweden)

    Gómez-Aguilar José Francisco

    2014-04-01

    Full Text Available In this paper we propose a fractional differential equation for the electrical RC and LC circuit in terms of the fractional time derivatives of the Caputo type. The order of the derivative being considered is 0 < ɣ ≤1. To keep the dimensionality of the physical parameters R, L, C the new parameter σ is introduced. This parameter characterizes the existence of fractional structures in the system. A relation between the fractional order time derivative ɣ and the new parameter σ is found. The numeric Laplace transform method was used for the simulation of the equations results. The results show that the fractional differential equations generalize the behavior of the charge, voltage and current depending of the values of ɣ. The classical cases are recovered by taking the limit when ɣ = 1. An analysis in the frequency domain of an RC circuit shows the application and use of fractional order differential equations.

  18. Oversampling analysis in fractional Fourier domain

    Institute of Scientific and Technical Information of China (English)

    ZHANG Feng; TAO Ran; WANG Yue

    2009-01-01

    Oversampling is widely used in practical applications of digital signal processing. As the fractional Fourier transform has been developed and applied in signal processing fields, it is necessary to consider the oversampling theorem in the fractional Fourier domain. In this paper, the oversampling theorem in the fractional Fourier domain is analyzed. The fractional Fourier spectral relation between the original oversampled sequence and its subsequences is derived first, and then the expression for exact reconstruction of the missing samples in terms of the subsequences is obtained. Moreover, by taking a chirp signal as an example, it is shown that, reconstruction of the missing samples in the oversampled signal Is suitable in the fractional Fourier domain for the signal whose time-frequency distribution has the minimum support in the fractional Fourier domain.

  19. Operator Fractional Brownian Motion and Martingale Differences

    Directory of Open Access Journals (Sweden)

    Hongshuai Dai

    2014-01-01

    Full Text Available It is well known that martingale difference sequences are very useful in applications and theory. On the other hand, the operator fractional Brownian motion as an extension of the well-known fractional Brownian motion also plays an important role in both applications and theory. In this paper, we study the relation between them. We construct an approximation sequence of operator fractional Brownian motion based on a martingale difference sequence.

  20. Early Predictors of Middle School Fraction Knowledge

    OpenAIRE

    Drew H. Bailey; Siegler, Robert S.; David C Geary

    2014-01-01

    Recent findings that earlier fraction knowledge predicts later mathematics achievement raise the question of what predicts later fraction knowledge. Analyses of longitudinal data indicated that whole number magnitude knowledge in first grade predicted knowledge of fraction magnitudes in middle school, controlling for whole number arithmetic proficiency, domain general cognitive abilities, parental income and education, race, and gender. Similarly, knowledge of whole number arithmetic in first...