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Sample records for luminescent bacterial strains

  1. Piezoelectric and deformation potential effects of strain-dependent luminescence in semiconductor quantum well structures

    DEFF Research Database (Denmark)

    Zhang, Aihua; Peng, Mingzeng; Willatzen, Morten

    2017-01-01

    The mechanism of strain-dependent luminescence is important for the rational design of pressure-sensing devices. The interband momentum-matrix element is the key quantity for understanding luminescent phenomena. We analytically solved an infinite quantum well (IQW) model with strain, in the frame......The mechanism of strain-dependent luminescence is important for the rational design of pressure-sensing devices. The interband momentum-matrix element is the key quantity for understanding luminescent phenomena. We analytically solved an infinite quantum well (IQW) model with strain......, in the framework of the 6 × 6 k·p Hamiltonian for the valence states, to directly assess the interplay between the spin-orbit coupling and the strain-induced deformation potential for the interband momentum-matrix element. We numerically addressed problems of both the infinite and IQWs with piezoelectric fields...... to elucidate the effects of the piezoelectric potential and the deformation potential on the strain-dependent luminescence. The experimentally measured photoluminescence variatio½n as a function of pressure can be qualitatively explained by the theoretical results....

  2. Determination of Silver Ions Toxicity in Short-Term and Long-Term Experiments Using a Luminescent Recombinant Strain of E. coli

    Directory of Open Access Journals (Sweden)

    Tatiana P. Yudina

    2013-01-01

    Full Text Available The effects of silver ions on the luminescent recombinant strain of Escherichia coli carrying luxCDABE operon of Vibrio fischeri were investigated. The toxicity of silver ions was determined in 30 minutes and in chronic 24 hours experiments. Changes in the luminescence intensity and in the growth rate of bacteria were considered as a measure of silver ions toxicity within the range of concentrations applied. The effect of silver ions was demonstrated to be strongly dependent on the concentration of bacteria and on the medium composition. EC50 values were 0.018 mg/l after 30 min exposure and 0.014 mg/l after 10 hours of bacterial growth. Comparison of two modifications of the experiment showed that silver ions have a strong non-specific toxicity, as well as a specific effect on bacterial cells

  3. Effect of concentrating and exposing the bioluminescent bacteria to the non-luminescent allo-bacterial extracellular products on their luminescence

    Digital Repository Service at National Institute of Oceanography (India)

    Ravindran, J.; Priya, G.G.; Kannapiran, E.

    of cell-cell physical contact will be high. In this study, the physical proximity was artificially enhanced between cells and the effect on luminescence in the concentrated cells in the normal culture medium and in the presence of other non-bacterial cell...

  4. Strain modulated defect luminescence in ZnO nanostructures grown on Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hung-Ing; Hsiao, Jui-Ju; Huang, Yi-Jen; Wang, Jen-Cheng [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan, ROC (China); Wu, Ya-Fen [Department of Electronic Engineering, Ming Chi University of Technology, Taishan, New Taipei 243, Taiwan, ROC (China); Lu, Bing-Yuh [Department of Electrical Engineering, Tun Gnan University, Shenkeng, New Taipei 222, Taiwan, ROC (China); Nee, Tzer-En, E-mail: neete@mail.cgu.edu.tw [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan, ROC (China)

    2015-12-15

    The strain modulated defect green luminescence from ZnO nanostructures grown on silicon substrates has been investigated in-depth. According to the Warren–Averbach Fourier analysis of the X-ray diffraction profiles, both the internal strain and the average crystallite size of the well-ordered nano-size ZnO nanostructures could be subtly modulated by careful adjustment of the aqueous solution of zinc nitrate (Zn(NO{sub 3}){sub 2}) and ammonium hydroxide (NH{sub 3}OH) used in the hydrothermal treatment. Visible defect-related and ultraviolet band-to-band emissions were characterized using temperature-dependent photoluminescence measurements over a broad temperature range from 20 to 300 K. It was found that the thermal-related tensile strain led to the blueshift of the green emission with increasing temperature, while the violet and ultraviolet emissions were thermally insensitive. These spectral observations were substantially corroborated by the deformation potential theory. - Highlights: • The strain modulated defect green luminescence from ZnO nanostructures. • Visible and ultraviolet emissions were characterized using photoluminescence. • The tensile strain led to the blueshift of the green emission. • The spectral observations were corroborated by the deformation potential theory.

  5. Physical and functional maps of the luminescence gene cluster in an autoinducer-deficient Vibrio fischeri strain isolated from a squid light organ.

    Science.gov (United States)

    Gray, K M; Greenberg, E P

    1992-07-01

    Vibrio fischeri ES114 is an isolate representing the specific bacterial light organ symbiont of the squid Euprymna scolopes. An interesting feature of this strain of V. fischeri is that it is visibly luminous within the light organ of the squid host but is nonluminous when grown under standard laboratory conditions. Luminescence can be restored in laboratory culture, however, by the addition of autoinducer, a species-specific inducer of the V. fischeri luminescence (lux) genes. Most other isolates of V. fischeri produce autoinducer in sufficient quantities to induce luminescence in laboratory culture. We have cloned an 8.8-kb DNA fragment from V. fischeri ES114 that encodes all of the functions necessary for luminescence in Escherichia coli in the absence of exogenous autoinducer. This DNA contains both of the recognized V. fischeri lux regulatory genes, one of which (luxI) directs E. coli to synthesize autoinducer. The organization of the individual lux genes within this DNA fragment appears to be the same as that in the other strains of V. fischeri studied; the restriction map of the V. fischeri ES114 lux DNA has diverged substantially, however, from the largely conserved maps of V. fischeri MJ1 and ATCC 7744. Although E. coli containing the V. fischeri ES114 lux DNA synthesizes considerable amounts of autoinducer, V. fischeri ES114 synthesizes autoinducer only in small amounts, even when transcription of the lux genes, including luxI, is activated by the addition of exogenous autoinducer. Nonetheless, transconjugants of V. fischeri ES114 that contain multicopy plasmids bearing the ES114 lux genes synthesize sufficient autoinducer to induce luminescence. These results suggest that V. fischeri ES11r does not lack a functional luxl, nor is it deficient in the ability to synthesize metabolic precursors for autoinducer synthesis.

  6. Development of luminescent pH sensor films for monitoring bacterial growth through tissue.

    Science.gov (United States)

    Wang, Fenglin; Raval, Yash; Chen, Hongyu; Tzeng, Tzuen-Rong J; DesJardins, John D; Anker, Jeffrey N

    2014-02-01

    Although implanted medical devices (IMDs) offer many benefits, they are susceptible to bacterial colonization and infections. Such infections are difficult to treat because bacteria could form biofilms on the implant surface, which reduce antibiotics penetration and generate local dormant regions with low pH and low oxygen. In addition, these infections are hard to detect early because biofilms are often localized on the surface. Herein, an optical sensor film is developed to detect local acidosis on an implanted surface. The film contains both upconverting particles (UCPs) that serve as a light source and a pH indicator that alters the luminescence spectrum. When irradiated with 980 nm light, the UCPs produce deeply penetrating red light emission, while generating negligible autofluorescence in the tissue. The basic form of the pH indicator absorbs more of upconversion luminescence at 661 nm than at 671 nm and consequently the spectral ratio indicates pH. Implanting this pH sensor film beneath 6-7 mm of porcine tissue does not substantially affect the calibration curve because the peaks are closely spaced. Furthermore, growth of Staphylococcus epidermidis on the sensor surface causes a local pH decrease that can be detected non-invasively through the tissue. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Antifungal activity of bacterial strains from the rhizosphere of ...

    African Journals Online (AJOL)

    This study evaluated the antifungal action of biomolecules produced from the secondary metabolism of bacterial strains found in the rhizosphere of semi arid plants against human pathogenic Candida albicans. Crude extracts were obtained using ethyl acetate as an organic solvent and the bioactivity was assessed with a ...

  8. Identification and characterisation of potential biofertilizer bacterial strains

    Science.gov (United States)

    Karagöz, Kenan; Kotan, Recep; Dadaşoǧlu, Fatih; Dadaşoǧlu, Esin

    2016-04-01

    In this study we aimed that isolation, identification and characterizations of PGPR strains from rhizosphere of legume plants. 188 bacterial strains isolated from different legume plants like clover, sainfoin and vetch in Erzurum province of Turkey. These three plants are cultivated commonly in the Erzurum province. It was screen that 50 out of 188 strains can fix nitrogen and solubilize phosphate. These strains were identified via MIS (Microbial identification system). According to MIS identification results, 40 out of 50 strains were identified as Bacillus, 5 as Pseudomonas, 3 as Paenibacillus, 1 as Acinetobacter, 1 as Brevibacterium. According to classical test results, while the catalase test result of all isolates are positive, oxidase, KOH and starch hydrolysis rest results are variable.

  9. Antimicrobial resistance of bacterial strains isolated from avian cellulitis

    Directory of Open Access Journals (Sweden)

    MM Santos

    2014-03-01

    Full Text Available Avian cellulitis is an inflammatory process in the subcutaneous tissue, mainly located in the abdomen and thighs. This problem is commonly observed in poultry at slaughter and it is considered one of the major causes of condemnation of carcasses in Brazil. The aim of this study was to perform the microbial isolation of lesions of avian cellulitis from a processing plant located in the State of Goiás in order to analyze antimicrobial resistance by antibiogram test and to detect resistance genes by polymerase chain reaction. A total of 25 samples of avian cellulitis lesions were analyzed, from which 30 bacterial strains were isolated. There were eleven (44% strains of Escherichia coli, nine (36% strains of Staphylococcus epidermidis, seven (28% strains of Proteus mirabilis and three (12% strains of Manheimiahaemolytica. The antibiogram test showed that all strains were resistant to at least one antimicrobial. The gene of antimicrobial resistance tetB was detected in E. coli, S. epidermidis and P. mirabilis strains, and was the most frequently observed gene. The gene of antimicrobial resistance Sul1 was detected in all bacterial species, while tetA was found in E. coli and S. epidermidis strains, SHV in E. coli strains, S. epidermidis and P. mirabilis,and cat1 in one P. mirabilis strain. The results suggest a potential public health hazard due to the ability of these microorganisms to transmit antimicrobial resistancegenes to other microorganisms present in the intestinal tract of humans and animals, which may affect clinical-medical usage of these drugs.

  10. Carbazole degradation in the soil microcosm by tropical bacterial strains

    Directory of Open Access Journals (Sweden)

    Lateef B. Salam

    2015-01-01

    Full Text Available In a previous study, three bacterial strains isolated from tropical hydrocarbon-contaminated soils and phylogenetically identified as Achromobacter sp. strain SL1, Pseudomonassp. strain SL4 and Microbacterium esteraromaticum strain SL6 displayed angular dioxygenation and mineralization of carbazole in batch cultures. In this study, the ability of these isolates to survive and enhance carbazole degradation in soil were tested in field-moist microcosms. Strain SL4 had the highest survival rate (1.8 x 107 cfu/g after 30 days of incubation in sterilized soil, while there was a decrease in population density in native (unsterilized soil when compared with the initial population. Gas chromatographic analysis after 30 days of incubation showed that in sterilized soil amended with carbazole (100 mg/kg, 66.96, 82.15 and 68.54% were degraded by strains SL1, SL4 and SL6, respectively, with rates of degradation of 0.093, 0.114 and 0.095 mg kg−1 h−1. The combination of the three isolates as inoculum in sterilized soil degraded 87.13% carbazole at a rate of 0.121 mg kg−1 h−1. In native soil amended with carbazole (100 mg/kg, 91.64, 87.29 and 89.13% were degraded by strains SL1, SL4 and SL6 after 30 days of incubation, with rates of degradation of 0.127, 0.121 and 0.124 mg kg−1h−1, respectively. This study successfully established the survivability (> 106 cfu/g detected after 30 days and carbazole-degrading ability of these bacterial strains in soil, and highlights the potential of these isolates as seed for the bioremediation of carbazole-impacted environments.

  11. Detection of antibiotic resistance in clinical bacterial strains from pets

    OpenAIRE

    Poeta, P.; Rodrigues, J.

    2008-01-01

    The identification of different bacterial strains and the occurrence of antibiotic resistance were investigated in several infection processes of pets as skin abscess with purulent discharge, bronco alveolar fluid, earwax, urine, mammary, and eye fluid. Streptococcus spp. and Staphylococcus spp. were the most detected in the different samples. A high frequency of antimicrobial resistance has been observed and this could reflect the wide use of antimicrobials in pets, making the effectiveness ...

  12. Evaluation of different lactic acid bacterial strains for probiotic characteristics

    OpenAIRE

    B. Srinu,; T. Madhava Rao,; P. V. Mallikarjuna Reddy; K. Kondal Reddy

    2013-01-01

    Objective: The objective of the present study was to collect different Lactic acid bacterial strains from culture collection centers and screen their functional probiotic characteristics such as acid tolerance, bile tolerance, antibacterial activity and antibiotic sensitivity for their commercial use. Materials and Methods: Acid and bile tolerence of selected LAB(Lactic acid bacteria) was determined. The antibiotic resistance of Lactobacillus species was assessed using different antibiotic di...

  13. Bacterial strain changes during chronic otitis media surgery.

    Science.gov (United States)

    Kim, G J; Yoo, S; Han, S; Bu, J; Hong, Y; Kim, D-K

    2017-09-01

    Cultures obtained from pre-operative middle-ear swabs from patients with chronic otitis media have traditionally been used to guide antibiotic selection. This study investigated changes in the bacterial strains of the middle ear during chronic otitis media surgery. Pre-operative bacterial cultures of otorrhoea, and peri-operative cultures of the granulation tissue in either the middle ear or mastoid cavity, were obtained. Post-operative cultures were selectively obtained when otorrhoea developed after surgery. Bacterial growth was observed in 45.5 per cent of pre-operative cultures, 13.5 per cent of peri-operative cultures and 4.5 per cent of post-operative cultures. Methicillin-resistant Staphylococcus aureus was identified as the most common bacteria in all pre-operative (32.4 per cent), peri-operative (52.4 per cent) and post-operative (71.4 per cent) tests, and the percentage of Methicillin-resistant S aureus increased from the pre- to the post-operative period. The bacterial culture results for post-operative otorrhoea showed low agreement with those for pre-operative or peri-operative culture, and strain re-identification was required.

  14. Transforming microbial genotyping: a robotic pipeline for genotyping bacterial strains.

    Directory of Open Access Journals (Sweden)

    Brian O'Farrell

    Full Text Available Microbial genotyping increasingly deals with large numbers of samples, and data are commonly evaluated by unstructured approaches, such as spread-sheets. The efficiency, reliability and throughput of genotyping would benefit from the automation of manual manipulations within the context of sophisticated data storage. We developed a medium- throughput genotyping pipeline for MultiLocus Sequence Typing (MLST of bacterial pathogens. This pipeline was implemented through a combination of four automated liquid handling systems, a Laboratory Information Management System (LIMS consisting of a variety of dedicated commercial operating systems and programs, including a Sample Management System, plus numerous Python scripts. All tubes and microwell racks were bar-coded and their locations and status were recorded in the LIMS. We also created a hierarchical set of items that could be used to represent bacterial species, their products and experiments. The LIMS allowed reliable, semi-automated, traceable bacterial genotyping from initial single colony isolation and sub-cultivation through DNA extraction and normalization to PCRs, sequencing and MLST sequence trace evaluation. We also describe robotic sequencing to facilitate cherrypicking of sequence dropouts. This pipeline is user-friendly, with a throughput of 96 strains within 10 working days at a total cost of 200,000 items were processed by two to three people. Our sophisticated automated pipeline can be implemented by a small microbiology group without extensive external support, and provides a general framework for semi-automated bacterial genotyping of large numbers of samples at low cost.

  15. Perturbing Tandem Energy Transfer in Luminescent Heterobinuclear Lanthanide Coordination Polymer Nanoparticles Enables Real-Time Monitoring of Release of the Anthrax Biomarker from Bacterial Spores.

    Science.gov (United States)

    Gao, Nan; Zhang, Yunfang; Huang, Pengcheng; Xiang, Zhehao; Wu, Fang-Ying; Mao, Lanqun

    2018-06-05

    Lanthanide-based luminescent sensors have been widely used for the detection of the anthrax biomarker dipicolinic acid (DPA). However, mainly based on DPA sensitization to the lanthanide core, most of them failed to realize robust detection of DPA in bacterial spores. We proposed a new strategy for reliable detection of DPA by perturbing a tandem energy transfer in heterobinuclear lanthanide coordination polymer nanoparticles simply constructed by two kinds of lanthanide ions, Tb 3+ and Eu 3+ , and guanosine 5'-monophosphate. This smart luminescent probe was demonstrated to exhibit highly sensitive and selective visual luminescence color change upon exposure to DPA, enabling accurate detection of DPA in complex biosystems such as bacterial spores. DPA release from bacterial spores on physiological germination was also successfully monitored in real time by confocal imaging. This probe is thus expected to be a powerful tool for efficient detection of bacterial spores in responding to anthrax threats.

  16. Fluorescence-PCR Assays and Isolation of Luminescent Bacterial Clones Using an Automated Plate Reader

    Science.gov (United States)

    Crowley, Thomas E.

    2011-01-01

    The genes responsible for luminescence in various species of the marine microorganism "Photobacterium", have been used for many years as a tool by researchers and instructors. In particular, the "lux" operon of "Photobacterium fischeri" has been used by many instructors to teach recombinant DNA techniques. Two methods using an automated plate…

  17. Evaluation of different lactic acid bacterial strains for probiotic characteristics

    Directory of Open Access Journals (Sweden)

    B. Srinu,

    2013-08-01

    Full Text Available Objective: The objective of the present study was to collect different Lactic acid bacterial strains from culture collection centers and screen their functional probiotic characteristics such as acid tolerance, bile tolerance, antibacterial activity and antibiotic sensitivity for their commercial use. Materials and Methods: Acid and bile tolerence of selected LAB(Lactic acid bacteria was determined. The antibiotic resistance of Lactobacillus species was assessed using different antibiotic discs on de Mann Rogosa Sharpe broth (MRS agar plates seeded with the test probiotic organism. The antibacterial activity of LAB was assessed by using well diffusion method.Results: Among the six probiotic strains tested, all showed good survivability at high bile salt concentration (0.3 to 2.0 % oxgall and good growth at a low pH of 1.5 to 3.5. These probiotic species showed good survival abilities in acidic pH of 2.0 to 3.5 except Lactobacillus delbrueckii subspp. bulgaricus 281 which did not grown at pH of 2.0. Lactobacillus fermentum 141 was able to grow even at pH of 1.5 also. Among the six lactic acid species, Lactobacillus fermentum 141 (except Tetracycline, Lactobacillus delbrueckii subspp. Bulgaricus 281 except (Cefpodoxime and all other LAB were resistant to all the antibiotics tested (Ampicillin, Nalidixic acid , Ciprofloxacin ,Co-Trimoxazole, Gentamicin and Cefpodoxime. All these probiotic organisms were screened for their in vitro inhibition ability against pathogenic microorganisms namely, E.coli ATCC (American type culture collection centre, Pseudomonas aeruginosa, Salmonella paratyphi, Staphylococcus aureus. Lactobacillus delbrueckii subspp. bulgaricus 281, Lactobacillus casei 297 and Lactobacillus fermentum 141 inhibited the growth of all the pathogenic bacteria used in the study. Conclusion: The study indicated Lactobacillus fermentum 141 and Lactobacillus casei 297 as potential functional probiotics for future in vivo studies for

  18. Isolation and characterization of a bacterial strain for aniline ...

    African Journals Online (AJOL)

    STORAGESEVER

    which the microbes enzymatically decompose and utilize in cellular ... dioxygenases, liberating ammonia and subsequently ... others). MATERIALS AND METHODS ... results were then interpreted for bacterial identification according to.

  19. Comparison of Bacterial Cellulose Production among Different Strains and Fermented Media

    Directory of Open Access Journals (Sweden)

    Maryam Jalili Tabaii

    2015-12-01

    Full Text Available The effect of different carbon sources on bacterial cellulose production by Gluconacetobacter xylinus (PTCC 1734 and two newly isolated strains (from vinegar under static culture conditions was studied. The production of bacterial cellulose was examined in modified Hestrin-Shramm medium by replacing D-glucose with other carbon sources. The results showed that the yield and characteristics of bacterial cellulose were influenced by the type of carbon source. Glycerol gave the highest yield in all of the studied strains (6%, 9.7% and 3.8% for S, A2 strain and Gluconacetobacter xylinus (PTCC 1734, respectively. The maximum dry bacterial cellulose weight in the glycerol containing medium is due to A2 strain (1.9 g l-1 in comparison to Gluconacetobacter xylinus as reference strain (0.76 g l-1. Although all of the studied strains were in Gluconacetobacter family, each used different sugars for maximum production after glycerol (mannitol and fructose for two newly isolated strains and glucose for Gluconacetobacter xylinus. The maximum moisture content was observed when sucrose and food-grade sucrose were used as carbon source. Contrary to expectations, while the maximum thickness of bacterial cellulose membrane was attained when glycerol was used, bacterial cellulose from glycerol had less moisture content than the others. The oxidized cellulose showed antibacterial activities, which makes it as a good candidate for food-preservatives.

  20. Colonization of Tomato Root by Antagonistic Bacterial Strains to Fusarium Wilt of Tomato

    Directory of Open Access Journals (Sweden)

    Arif Wibowo

    2005-12-01

    Full Text Available Fusarium wilt of tomato caused by Fusarium oxysporum f.sp. lycopersici (Fol is an important disease in tomato which cause a significant loss of yield in major growing regions of the world. This study examined the ability of bacterial strains antagonistic to F. oxysporum f.sp. lycopersici (H5, H22, H63, H71, Burkholderia cepacia strain 65 and 526 to colonize tomato seedlings and the effect of plant growth. The effect of bacterial population size and air temperature on the bacterial colonization and their spread along the root systems was also assessed.The results of this study showed that the bacterial population at 28°/23° C day/night temperature 14 days after planting was significantly greater than 23°/18° C for 4 of 6 strains tested. Although there was no significant effect of temperature on bacterial population observed in this study, the ability of the baacterial strains to colonize the rhizosphere was significantly different. Three strains (H5, B. cepacia strain 65 and 526 survived well in the rhizosphere and at 4 weeks after planting rhizosphere populations per gram fresh root were not significantly different from those recovered 2 weeks after planting. The largest population of the bacterial inoculants developed in the basal region of the roots and this differed between strains by log10 2.7 cfu/cm root. The bacterial populations in other parts of the root were also strain dependent. Strain H71, for example, was able to colonize the root segments at a high population level. However strain H63 was recovered only in small number in all root segments.

  1. Analysis of bacterial strains from contaminated and non ...

    African Journals Online (AJOL)

    Administrator

    2007-05-02

    May 2, 2007 ... A total 18 strains were collected from non-contaminated and contaminated environments, and were purified. All purified strains were characterized for Gram reaction and biochemical analysis. Screening for bioplastic production was done by Sudan black staining. Strains isolated from non-contaminated.

  2. Laboratory-Cultured Strains of the Sea Anemone Exaiptasia Reveal Distinct Bacterial Communities

    KAUST Repository

    Herrera Sarrias, Marcela; Ziegler, Maren; Voolstra, Christian R.; Aranda, Manuel

    2017-01-01

    Exaiptasia is a laboratory sea anemone model system for stony corals. Two clonal strains are commonly used, referred to as H2 and CC7, that originate from two genetically distinct lineages and that differ in their Symbiodinium specificity. However, little is known about their other microbial associations. Here, we examined and compared the taxonomic composition of the bacterial assemblages of these two symbiotic Exaiptasia strains, both of which have been cultured in the laboratory long-term under identical conditions. We found distinct bacterial microbiota for each strain, indicating the presence of host-specific microbial consortia. Putative differences in the bacterial functional profiles (i.e., enrichment and depletion of various metabolic processes) based on taxonomic inference were also detected, further suggesting functional differences of the microbiomes associated with these lineages. Our study contributes to the current knowledge of the Exaiptasia holobiont by comparing the bacterial diversity of two commonly used strains as models for coral research.

  3. Laboratory-Cultured Strains of the Sea Anemone Exaiptasia Reveal Distinct Bacterial Communities

    KAUST Repository

    Herrera Sarrias, Marcela

    2017-05-02

    Exaiptasia is a laboratory sea anemone model system for stony corals. Two clonal strains are commonly used, referred to as H2 and CC7, that originate from two genetically distinct lineages and that differ in their Symbiodinium specificity. However, little is known about their other microbial associations. Here, we examined and compared the taxonomic composition of the bacterial assemblages of these two symbiotic Exaiptasia strains, both of which have been cultured in the laboratory long-term under identical conditions. We found distinct bacterial microbiota for each strain, indicating the presence of host-specific microbial consortia. Putative differences in the bacterial functional profiles (i.e., enrichment and depletion of various metabolic processes) based on taxonomic inference were also detected, further suggesting functional differences of the microbiomes associated with these lineages. Our study contributes to the current knowledge of the Exaiptasia holobiont by comparing the bacterial diversity of two commonly used strains as models for coral research.

  4. StrainSeeker: fast identification of bacterial strains from raw sequencing reads using user-provided guide trees.

    Science.gov (United States)

    Roosaare, Märt; Vaher, Mihkel; Kaplinski, Lauris; Möls, Märt; Andreson, Reidar; Lepamets, Maarja; Kõressaar, Triinu; Naaber, Paul; Kõljalg, Siiri; Remm, Maido

    2017-01-01

    Fast, accurate and high-throughput identification of bacterial isolates is in great demand. The present work was conducted to investigate the possibility of identifying isolates from unassembled next-generation sequencing reads using custom-made guide trees. A tool named StrainSeeker was developed that constructs a list of specific k -mers for each node of any given Newick-format tree and enables the identification of bacterial isolates in 1-2 min. It uses a novel algorithm, which analyses the observed and expected fractions of node-specific k -mers to test the presence of each node in the sample. This allows StrainSeeker to determine where the isolate branches off the guide tree and assign it to a clade whereas other tools assign each read to a reference genome. Using a dataset of 100 Escherichia coli isolates, we demonstrate that StrainSeeker can predict the clades of E. coli with 92% accuracy and correct tree branch assignment with 98% accuracy. Twenty-five thousand Illumina HiSeq reads are sufficient for identification of the strain. StrainSeeker is a software program that identifies bacterial isolates by assigning them to nodes or leaves of a custom-made guide tree. StrainSeeker's web interface and pre-computed guide trees are available at http://bioinfo.ut.ee/strainseeker. Source code is stored at GitHub: https://github.com/bioinfo-ut/StrainSeeker.

  5. [3H] Thymidine incorporation to estimate growth rates of anaerobic bacterial strains

    International Nuclear Information System (INIS)

    Winding, A.

    1992-01-01

    The incorporation of [ 3 H] thymidine by axenic cultures of anaerobic bacteria was investigated as a means to measure growth. The three fermentative strains and one of the methanogenic strains tested incorporated [ 3 H] thymidine during growth. It is concluded that the [ 3 H] thymidine incorporation method underestimates bacterial growth in anaerobic environments

  6. Biodegradation of petroleum oil by certain bacterial strains

    International Nuclear Information System (INIS)

    Zakaria, A.E.M.

    1998-01-01

    Balaeam base oil was chosen as a model oil in the present study through which some abiotic treatments were implemented aiming at attenuating its naphthenic and aromatic contents; such as the adsorptive technique and the gamma-irradiation technique . In an attempt to apply the biodegrading bacteria as oil pollutant bio indicators upon coastal water samples, a correlation between hydrocarbon concentration and the relative enumeration of the bacterial oil degraders was detected for some litter locations along the mediterranean Sea shore west and east Delta, Suez canal. and suez gulf. 24 petroleum utilizing bacterial isolates were isolated from El-Zayteia port (suez) and identified by morphological, physiological and environmental examination . the biodegradation capacity of the isolates towards the chosen model oil and its separate components was studied in comparison with the standard isolate pseudomonas aeruginosa. Further, the role of the bacterial plasmids taking part in the biodegradation process was investigated as well

  7. Isolation and identification of biocellulose-producing bacterial strains from Malaysian acidic fruits.

    Science.gov (United States)

    Voon, W W Y; Rukayadi, Y; Meor Hussin, A S

    2016-05-01

    Biocellulose (BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm (HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l(-1) in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l(-1) of BC production, respectively. Biocellulose (BC) is pure extracellular cellulose that is formed by many micro-organisms in the presence of carbon source and acidic condition. It can replace plant-based cellulose in multifarious applications due to its unique characteristics. In this study, three potential biocellulose-producing bacterial strains were obtained from Malaysian acidic fruits and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. This study reports for the first time the new biocellulose-producing bacterial strains isolated from Malaysian acidic fruits. © 2016 The

  8. Biodegradation of orange G by a novel isolated bacterial strain ...

    African Journals Online (AJOL)

    At these optimum levels of parameters, bacterial decolorization of orange G by 94.48% was obtained under static conditions. Biodegradation and decolorization of azo dye, orange G, was confirmed using UV-VIS spectrophotometry, thin layer chromatography (TLC) and fourier transform infrared spectroscopy (FTIR) and ...

  9. Promising Biological Indicator of Heavy Metal Pollution: Bioluminescent Bacterial Strains Isolated and Characterized from Marine Niches of Goa, India.

    Science.gov (United States)

    Thakre, Neha A; Shanware, Arti S

    2015-09-01

    In present study, several marine water samples collected from the North Goa Beaches, India for isolation of luminescent bacterial species. Isolates obtained labelled as DP1-5 and AB1-6. Molecular characterization including identification of a microbial culture using 16S rRNA gene based molecular technique and phylogenetic analysis confirmed that DP3 & AB1 isolates were Vibrio harveyi. All of the isolates demonstrated multiple metal resistances in terms of growth, with altered luminescence with variable metal concentration. Present investigations were an attempt towards exploring and reporting an updated diversity of bioluminescent bacterial species from various sites around the Goa, India which would be explored in future for constructing luminescence based biosensor for efficiently monitoring the level of hazardous metals in the environment.

  10. Defect luminescence and lattice strain in Mn{sup 2+} doped ZnGa{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Somasundaram, K.; Abhilash, K.P. [Department of Physics, Nallamuthu Gounder Mahalingam College, Pollachi, 642001 Coimbatore (India); Sudarsan, V., E-mail: vsudar@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Christopher Selvin, P., E-mail: pcsphyngmc@rediffmail.com [Department of Physics, Nallamuthu Gounder Mahalingam College, Pollachi, 642001 Coimbatore (India); Kadam, R.M. [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2016-06-15

    Undoped and Mn{sup 2+} doped ZnGa{sub 2}O{sub 4} phosphors were prepared by solution combustion method and characterized by XRD, SEM, luminescence and electron paramagnetic resonance (EPR) techniques. Based on XRD results, it is inferred that, strain in ZnGa{sub 2}O{sub 4} host lattice increases with incorporation of Mn{sup 2+} ions in the lattice. Mn{sup 2+} doping at concentration levels investigated, lead to significant reduction in the defect emission and this has been attributed to the formation of higher oxidation states of Mn ions in the lattice. Electron Paramagnetic Resonance studies confirmed that majority of Mn ions exist as Mn{sup 2+} species and they occupy tetrahedral Zn{sup 2+} site in ZnGa{sub 2}O{sub 4} lattice with an average hyperfine coupling constant, A{sub iso}∼82 G.

  11. Volatile emissions from Mycobacterium avium subsp. paratuberculosis mirror bacterial growth and enable distinction of different strains.

    Directory of Open Access Journals (Sweden)

    Phillip Trefz

    Full Text Available Control of paratuberculosis in livestock is hampered by the low sensitivity of established direct and indirect diagnostic methods. Like other bacteria, Mycobacterium avium subsp. paratuberculosis (MAP emits volatile organic compounds (VOCs. Differences of VOC patterns in breath and feces of infected and not infected animals were described in first pilot experiments but detailed information on potential marker substances is missing. This study was intended to look for characteristic volatile substances in the headspace of cultures of different MAP strains and to find out how the emission of VOCs was affected by density of bacterial growth. One laboratory adapted and four field strains, three of MAP C-type and one MAP S-type were cultivated on Herrold's egg yolk medium in dilutions of 10(-0, 10(-2, 10(-4 and 10(-6. Volatile substances were pre-concentrated from the headspace over the MAP cultures by means of Solid Phase Micro Extraction (SPME, thermally desorbed from the SPME fibers and separated and identified by means of GC-MS. Out of the large number of compounds found in the headspace over MAP cultures, 34 volatile marker substances could be identified as potential biomarkers for growth and metabolic activity. All five MAP strains could clearly be distinguished from blank culture media by means of emission patterns based on these 34 substances. In addition, patterns of volatiles emitted by the reference strain were significantly different from the field strains. Headspace concentrations of 2-ethylfuran, 2-methylfuran, 3-methylfuran, 2-pentylfuran, ethyl acetate, 1-methyl-1-H-pyrrole and dimethyldisulfide varied with density of bacterial growth. Analysis of VOCs emitted from mycobacterial cultures can be used to identify bacterial growth and, in addition, to differentiate between different bacterial strains. VOC emission patterns may be used to approximate bacterial growth density. In a perspective volatile marker substances could be used to

  12. Volatile emissions from Mycobacterium avium subsp. paratuberculosis mirror bacterial growth and enable distinction of different strains.

    Science.gov (United States)

    Trefz, Phillip; Koehler, Heike; Klepik, Klaus; Moebius, Petra; Reinhold, Petra; Schubert, Jochen K; Miekisch, Wolfram

    2013-01-01

    Control of paratuberculosis in livestock is hampered by the low sensitivity of established direct and indirect diagnostic methods. Like other bacteria, Mycobacterium avium subsp. paratuberculosis (MAP) emits volatile organic compounds (VOCs). Differences of VOC patterns in breath and feces of infected and not infected animals were described in first pilot experiments but detailed information on potential marker substances is missing. This study was intended to look for characteristic volatile substances in the headspace of cultures of different MAP strains and to find out how the emission of VOCs was affected by density of bacterial growth. One laboratory adapted and four field strains, three of MAP C-type and one MAP S-type were cultivated on Herrold's egg yolk medium in dilutions of 10(-0), 10(-2), 10(-4) and 10(-6). Volatile substances were pre-concentrated from the headspace over the MAP cultures by means of Solid Phase Micro Extraction (SPME), thermally desorbed from the SPME fibers and separated and identified by means of GC-MS. Out of the large number of compounds found in the headspace over MAP cultures, 34 volatile marker substances could be identified as potential biomarkers for growth and metabolic activity. All five MAP strains could clearly be distinguished from blank culture media by means of emission patterns based on these 34 substances. In addition, patterns of volatiles emitted by the reference strain were significantly different from the field strains. Headspace concentrations of 2-ethylfuran, 2-methylfuran, 3-methylfuran, 2-pentylfuran, ethyl acetate, 1-methyl-1-H-pyrrole and dimethyldisulfide varied with density of bacterial growth. Analysis of VOCs emitted from mycobacterial cultures can be used to identify bacterial growth and, in addition, to differentiate between different bacterial strains. VOC emission patterns may be used to approximate bacterial growth density. In a perspective volatile marker substances could be used to diagnose MAP

  13. Functional morphology of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae), a bacterially luminous coral reef fish.

    Science.gov (United States)

    Dunlap, Paul V; Nakamura, Masaru

    2011-08-01

    Previous studies of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae) identified a ventral light organ, reflector, lens, duct, and a ventral diffuser extending from the throat to the caudal peduncle. The control and function of luminescence in this and other species of Siphamia, however, have not been defined. Morphological examination of fresh and preserved specimens identified additional components of the luminescence system involved in control and ventral emission of luminescence, including a retractable shutter over the ventral face of the light organ, contiguity of the ventral diffuser from the caudal peduncle to near the chin, and transparency of the bones and other tissues of the lower jaw. The shutter halves retract laterally, allowing the ventral release of light, and relax medially, blocking ventral light emission; topical application of norepinephrine to the exposed light organ resulted in retraction of the shutter halves, which suggests that operation of the shutter is under neuromuscular control. The extension of the diffuser to near the chin and transparency of the lower jaw allow a uniform emission of luminescence over the entire ventrum of the fish. The live aquarium-held fish were found to readily and consistently display ventral luminescence. At twilight, the fish left the protective association with their longspine sea urchin, Diadema setosum, and began to emit ventral luminescence and to feed on zooplankton. Ventral luminescence illuminated a zone below and around the fish, which typically swam close to the substrate. Shortly after complete darkness, the fish stopped feeding and emitting luminescence. These observations suggest that S. versicolor uses ventral luminescence to attract and feed on zooplankton from the reef benthos at twilight. Ventral luminescence may allow S. versicolor to exploit for feeding the gap at twilight in the presence of potential predators as the reef transitions from diurnally active to

  14. Use of colony-based bacterial strain typing for tracking the fate of Lactobacillus strains during human consumption

    Directory of Open Access Journals (Sweden)

    Drevinek Pavel

    2009-12-01

    Full Text Available Abstract Background The Lactic Acid Bacteria (LAB are important components of the healthy gut flora and have been used extensively as probiotics. Understanding the cultivable diversity of LAB before and after probiotic administration, and being able to track the fate of administered probiotic isolates during feeding are important parameters to consider in the design of clinical trials to assess probiotic efficacy. Several methods may be used to identify bacteria at the strain level, however, PCR-based methods such as Random Amplified Polymorphic DNA (RAPD are particularly suited to rapid analysis. We examined the cultivable diversity of LAB in the human gut before and after feeding with two Lactobacillus strains, and also tracked the fate of these two administered strains using a RAPD technique. Results A RAPD typing scheme was developed to genetically type LAB isolates from a wide range of species, and optimised for direct application to bacterial colony growth. A high-throughput strategy for fingerprinting the cultivable diversity of human faeces was developed and used to determine: (i the initial cultivable LAB strain diversity in the human gut, and (ii the fate of two Lactobacillus strains (Lactobacillus salivarius NCIMB 30211 and Lactobacillus acidophilus NCIMB 30156 contained within a capsule that was administered in a small-scale human feeding study. The L. salivarius strain was not cultivated from the faeces of any of the 12 volunteers prior to capsule administration, but appeared post-feeding in four. Strains matching the L. acidophilus NCIMB 30156 feeding strain were found in the faeces of three volunteers prior to consumption; after taking the Lactobacillus capsule, 10 of the 12 volunteers were culture positive for this strain. The appearance of both Lactobacillus strains during capsule consumption was statistically significant (p Conclusion We have shown that genetic strain typing of the cultivable human gut microbiota can be

  15. The Mechanism for Type I Interferon Induction by Mycobacterium tuberculosis is Bacterial Strain-Dependent.

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    Kirsten E Wiens

    2016-08-01

    Full Text Available Type I interferons (including IFNαβ are innate cytokines that may contribute to pathogenesis during Mycobacterium tuberculosis (Mtb infection. To induce IFNβ, Mtb must gain access to the host cytosol and trigger stimulator of interferon genes (STING signaling. A recently proposed model suggests that Mtb triggers STING signaling through bacterial DNA binding cyclic GMP-AMP synthase (cGAS in the cytosol. The aim of this study was to test the generalizability of this model using phylogenetically distinct strains of the Mtb complex (MTBC. We infected bone marrow derived macrophages with strains from MTBC Lineages 2, 4 and 6. We found that the Lineage 6 strain induced less IFNβ, and that the Lineage 2 strain induced more IFNβ, than the Lineage 4 strain. The strains did not differ in their access to the host cytosol and IFNβ induction by each strain required both STING and cGAS. We also found that the three strains shed similar amounts of bacterial DNA. Interestingly, we found that the Lineage 6 strain was associated with less mitochondrial stress and less mitochondrial DNA (mtDNA in the cytosol compared with the Lineage 4 strain. Treating macrophages with a mitochondria-specific antioxidant reduced cytosolic mtDNA and inhibited IFNβ induction by the Lineage 2 and 4 strains. We also found that the Lineage 2 strain did not induce more mitochondrial stress than the Lineage 4 strain, suggesting that additional pathways contribute to higher IFNβ induction. These results indicate that the mechanism for IFNβ by Mtb is more complex than the established model suggests. We show that mitochondrial dynamics and mtDNA contribute to IFNβ induction by Mtb. Moreover, we show that the contribution of mtDNA to the IFNβ response varies by MTBC strain and that additional mechanisms exist for Mtb to induce IFNβ.

  16. Characterization and optimization of antibiotic resistant bacterial strains for polyhydroxyalkanoates (phas) production

    International Nuclear Information System (INIS)

    Rehman, S. U.; Jamil, N.; Hussain, S.

    2005-01-01

    In this investigation, sugarcane soil, sewage water and soil containing long chain hydrocarbons was screened to obtain bacterial strains that were able to synthesize poly-beta-hydroxyalkanoates (PHA). The potential to synthesize PHA was tested qualitatively by Sudan Black staining of colonies growing in glucose and sucrose. Sixteen bacterial strains were isolated, purified and characterized for Gram reaction, biochemical analysis and PHA production. Isolates showed a wide range of tolerance to different commonly used antibiotics. PHA extraction was done by solvent extraction and hypochlorite digestion method. PHA production was optimized for different nitrogen concentrations. (author)

  17. Isolation of Bacterial Strain for Biodegradation of Fats, Oil and Grease

    International Nuclear Information System (INIS)

    Alkhatib, M.F.; Mohd Zahangir Alam; Shabana, H.F.M.

    2015-01-01

    Fat, oil and grease (FOG) deposition is one of the major problems that harm the environment and cause dissatisfaction for human. Uncontrolled and un-pre-treated FOG removal from the kitchen could lead to its accumulation in the piping system. Problems include the interference of fat with the aerobic microorganisms that are responsible in treating the wastewater by reducing oxygen transfer rates and for anaerobic microorganisms; their efficiency could also be reduced due to the reduction of the transport of soluble substrates to the bacterial biomass. Biodegradation could be one of the effective means to treat FOG. The main objective of this study is to isolate bacterial strains from the FOG waste and identify the strains that are capable in biodegrading FOG waste. FOG sample was collected from a sewer manhole. Enrichment technique was applied, followed by isolation of bacterial strains to determine which strain is able to degrade the FOG deposition. Some morphology for the bacterial strain was done to determine its characteristics. (author)

  18. Highly luminescent, high-indium-content InGaN film with uniform composition and full misfit-strain relaxation

    Science.gov (United States)

    Fischer, A. M.; Wei, Y. O.; Ponce, F. A.; Moseley, M.; Gunning, B.; Doolittle, W. A.

    2013-09-01

    We have studied the properties of thick InxGa1-xN films, with indium content ranging from x ˜ 0.22 to 0.67, grown by metal-modulated epitaxy. While the low indium-content films exhibit high density of stacking faults and dislocations, a significant improvement in the crystalline quality and optical properties has been observed starting at x ˜ 0.6. Surprisingly, the InxGa1-xN film with x ˜ 0.67 exhibits high luminescence intensity, low defect density, and uniform full lattice-mismatch strain relaxation. The efficient strain relaxation is shown to be due to a critical thickness close to the monolayer range. These films were grown at low temperatures (˜400 °C) to facilitate indium incorporation and with precursor modulation to enhance surface morphology and metal adlayer diffusion. These findings should contribute to the development of growth techniques for nitride semiconductors under high lattice misfit conditions.

  19. Research on heavy oil degradation by four thermophilic bacterial strains

    Energy Technology Data Exchange (ETDEWEB)

    Bao, M.; Chen, Q.; Liu, Z.; Li, Y. [Ocean Univ. of China, Qingdao, Shandong (China)

    2009-07-01

    The Shengli oilfield is the second largest onshore oil field in China, with a crude oil output of approximately 30 million tons per year. The large quantities of wastewater that are produced during thermal recovery methods have posed a challenge in terms of water reuse, reinjection and discharge. The important aspect of wastewater treatment is the removal of residual heavy oil. Biological methods are considered to be efficient in solving this problem. This paper reported on a study in which 4 thermophilic microorganisms which had the ability to biodegrade heavy oil were screened from heavy oil wastewater in the Shengli oilfield. Their degradation to heavy oil was discussed and the suitable biodegradation conditions of these bacteria were investigated. The study showed that the degrading efficiency of heavy oil by the 4 bacteria was up to 42.0, 47.6, 55.6 and 43.4 per cent in the wastewater which contained 500 mg per litre of heavy oil, respectively. The crude oil samples were analyzed using gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS) before and after degradation. The single 4 strains demonstrated strong biodegradability to normal alkanes and aromatics, and the average degrading efficiency was about 50 and 35 per cent. The degrading efficiency of the mixed 4 strains was better than the single ones, particularly for the poor biodegradable hydrocarbons such as phenanthrenes and fluorines. 21 refs., 2 tabs., 17 figs.

  20. A luminescent nisin biosensor

    Science.gov (United States)

    Immonen, Nina; Karp, Matti

    2006-02-01

    Nisin is a lantibiotic, an antibacterial peptide produced by certain Lactococcus lactis strains that kills or inhibits the growth of other bacteria. Nisin is widely used as a food preservative, and its long-time use suggests that it can be generally regarded as safe. We have developed a method for determining the amount of nisin in food samples that is based on luminescent biosensor bacteria. Bacterial luciferase operon luxABCDE was inserted into plasmid pNZ8048, and the construct was transformed by electroporation into Lc. lactis strain NZ9800, whose ability to produce nisin has been erased by deletion of the gene nisA. The operon luxABCDE has been modified to be functional in gram-positive bacteria to confer a bioluminescent phenotype without the requirement of adding an exogenous substrate. In the plasmid pNZ8048, the operon was placed under control of the nisin-inducible nisA promoter. The chromosomal nisRK genes of Lc. lactis NZ9800 allow it to sense nisin in the environment and relay this signal via signal transduction proteins NisK and NisR to initiate transcription from nisA promoter. In the case of our sensor bacteria, this leads to production of luciferase and, thus, luminescence that can be directly measured from living bacteria. Luminescence can be detected as early as within minutes of induction. The nisin assay described here provides a detection limit in the sub-picogram level per ml, and a linear area between 1 - 1000 pg/ml. The sensitivity of this assay exceeds the performance of all previously published methods.

  1. Simultaneous Microcystis Algicidal and Microcystin Degrading Capability by a Single Acinetobacter Bacterial Strain.

    Science.gov (United States)

    Li, Hong; Ai, Hainan; Kang, Li; Sun, Xingfu; He, Qiang

    2016-11-01

    Measures for removal of toxic harmful algal blooms often cause lysis of algal cells and release of microcystins (MCs). In this study, Acinetobacter sp. CMDB-2 that exhibits distinct algal lysing activity and MCs degradation capability was isolated. The physiological response and morphological characteristics of toxin-producing Microcystis aeruginosa, the dynamics of intra- and extracellular MC-LR concentration were studied in an algal/bacterial cocultured system. The results demonstrated that Acinetobacter sp. CMDB-2 caused thorough decomposition of algal cells and impairment of photosynthesis within 24 h. Enhanced algal lysis and MC-LR release appeared with increasing bacterial density from 1 × 10 3 to 1 × 10 7 cells/mL; however, the MC-LR was reduced by nearly 94% within 14 h irrespective of bacterial density. Measurement of extracellular and intracellular MC-LR revealed that the toxin was decreased by 92% in bacterial cell incubated systems relative to control and bacterial cell-free filtrate systems. The results confirmed that the bacterial metabolite caused 92% lysis of Microcystis aeruginosa cells, whereas the bacterial cells were responsible for approximately 91% reduction of MC-LR. The joint efforts of the bacterium and its metabolite accomplished the sustainable removal of algae and MC-LR. This is the first report of a single bacterial strain that achieves these dual actions.

  2. Distinct Bacterial Composition Associated with Different Laboratory-cultured Aiptasia Strains Across Two Thermal Conditions

    KAUST Repository

    Ahmed, Hanin

    2018-01-01

    laboratory model system to study the role of the coral microbiome. Analyses of the bacterial compositions associated with different Aiptasia strains across two temperatures (25 °C and 32 °C), based on 16S rRNA gene sequencing. This study aims also to identify

  3. Radioprotective effect of garlic extract on some bacterial strains with different radiation sensitivities

    International Nuclear Information System (INIS)

    Tawfik, Z.S.; Abushady, M.R.

    1992-01-01

    The radioprotective effect of garlic on four bacterial strains with different degrees of radiation sensitivities was investigated. The presence of garlic led to an increase in d-10 value of Ps. Aeruginosa, S. aureus and S. typhimurium by 160%, 50%, and 30% respectively. The protective efficiency of garlic against radiation was noticed to be proportional to its concentration in a given inoculum size. Garlic extract up to 180 micro liter per 10 8 inoculum size of B. cereus showed no protective effect. This fact was attributed to the existence of sulphur compounds in the given strain. Higher garlic concentrations appeared to affect the cloning efficiency of a given strain. 4fig., 2tab

  4. Systematic determination of the mosaic structure of bacterial genomes: species backbone versus strain-specific loops

    Directory of Open Access Journals (Sweden)

    Gendrault-Jacquemard A

    2005-07-01

    Full Text Available Abstract Background Public databases now contain multitude of complete bacterial genomes, including several genomes of the same species. The available data offers new opportunities to address questions about bacterial genome evolution, a task that requires reliable fine comparison data of closely related genomes. Recent analyses have shown, using pairwise whole genome alignments, that it is possible to segment bacterial genomes into a common conserved backbone and strain-specific sequences called loops. Results Here, we generalize this approach and propose a strategy that allows systematic and non-biased genome segmentation based on multiple genome alignments. Segmentation analyses, as applied to 13 different bacterial species, confirmed the feasibility of our approach to discern the 'mosaic' organization of bacterial genomes. Segmentation results are available through a Web interface permitting functional analysis, extraction and visualization of the backbone/loops structure of documented genomes. To illustrate the potential of this approach, we performed a precise analysis of the mosaic organization of three E. coli strains and functional characterization of the loops. Conclusion The segmentation results including the backbone/loops structure of 13 bacterial species genomes are new and available for use by the scientific community at the URL: http://genome.jouy.inra.fr/mosaic.

  5. Expert Opinion on Three Phage Therapy Related Topics: Bacterial Phage Resistance, Phage Training and Prophages in Bacterial Production Strains

    Directory of Open Access Journals (Sweden)

    Christine Rohde

    2018-04-01

    Full Text Available Phage therapy is increasingly put forward as a “new” potential tool in the fight against antibiotic resistant infections. During the “Centennial Celebration of Bacteriophage Research” conference in Tbilisi, Georgia on 26–29 June 2017, an international group of phage researchers committed to elaborate an expert opinion on three contentious phage therapy related issues that are hampering clinical progress in the field of phage therapy. This paper explores and discusses bacterial phage resistance, phage training and the presence of prophages in bacterial production strains while reviewing relevant research findings and experiences. Our purpose is to inform phage therapy stakeholders such as policy makers, officials of the competent authorities for medicines, phage researchers and phage producers, and members of the pharmaceutical industry. This brief also points out potential avenues for future phage therapy research and development as it specifically addresses those overarching questions that currently call for attention whenever phages go into purification processes for application.

  6. Effect of CuO Nanoparticles over Isolated Bacterial Strains from Agricultural Soil

    International Nuclear Information System (INIS)

    Concha-Guerrero, S.I.; Pinon-Castillo, H.A.; Luna-Velasco, A.; Orrantia-Borunda, E.; Brito, E.M.S.; Tarango-Rivero, S.H.; Caretta, C.A.; Duran, R.

    2014-01-01

    The increased use of the nanoparticles (NPs) on several processes is notorious. In contrast the eco toxicological effects of NPs have been scarcely studied. The main current researches are related to the oxide metallic NPs. In the present work, fifty-six bacterial strains were isolated from soil, comprising 17 different OTUs distributed into 3 classes: Bacilli (36 strains), Flavobacteria (2 strains), and Gamma proteobacteria (18 strains). Copper oxide nanoparticles (CuONPs) were synthesized using a process of chemical precipitation. The obtained CuONPs have a spherical shape and primary size less than 17 nm. Twenty-one strains were used to evaluate the cytotoxicity of CuONPs and 11 of these strains showed high sensibility. Among those 11 strains, 4 (Brevibacillus later osporus strain CSS8, Chryseobacterium indoltheticum strain CSA28, and Pantoea ananatis strains CSA34 and CSA35) were selected to determine the kind of damage produced. The CuONPs toxic effect was observed at expositions over 25 mg·L -1 and the damage to cell membrane above 160 mg·L -1 . The electron microscopy showed the formation of cavities, holes, membrane degradation, blebs, cellular collapse, and lysis. These toxic effects may probably be due to the ions interaction, the oxide-reduction reactions, and the generation of reactive species

  7. Exploring the Potentiality of Novel Rhizospheric Bacterial Strains against the Rice Blast Fungus Magnaporthe oryzae

    Science.gov (United States)

    Amruta, Narayanappa; Prasanna Kumar, M. K.; Puneeth, M. E.; Sarika, Gowdiperu; Kandikattu, Hemanth Kumar; Vishwanath, K.; Narayanaswamy, Sonnappa

    2018-01-01

    Rice blast caused by Magnaporthe oryzae is a major disease. In the present study, we aimed to identify and evaluate the novel bacterial isolates from rice rhizosphere for biocontrol of M. oryzae pathogen. Sixty bacterial strains from the rice plant’s rhizosphere were tested for their biocontrol activity against M. oryzae under in vitro and in vivo. Among them, B. amyloliquefaciens had significant high activity against the pathogen. The least disease severity and highest germination were recorded in seeds treated with B. amyloliquefaciens UASBR9 (0.96 and 98.00%) compared to untreated control (3.43 and 95.00%, respectively) under in vivo condition. These isolates had high activity of enzymes in relation to growth promoting activity upon challenge inoculation of the pathogen. The potential strains were identified based on 16S rRNA gene sequencing and dominance of these particular genes were associated in Bacillus strains. These strains were also confirmed for the presence of antimicrobial peptide biosynthetic genes viz., srfAA (surfactin), fenD (fengycin), spaS (subtilin), and ituC (iturin) related to secondary metabolite production (e.g., AMPs). Overall, the results suggested that application of potential bacterial strains like B. amyloliquefaciens UASBR9 not only helps in control of the biological suppression of one of the most devastating rice pathogens, M. grisea but also increases plant growth along with a reduction in application of toxic chemical pesticides. PMID:29628819

  8. Pyroprinting: a rapid and flexible genotypic fingerprinting method for typing bacterial strains.

    Science.gov (United States)

    Black, Michael W; VanderKelen, Jennifer; Montana, Aldrin; Dekhtyar, Alexander; Neal, Emily; Goodman, Anya; Kitts, Christopher L

    2014-10-01

    Bacterial strain typing is commonly employed in studies involving epidemiology, population ecology, and microbial source tracking to identify sources of fecal contamination. Methods for differentiating strains generally use either a collection of phenotypic traits or rely on some interrogation of the bacterial genotype. This report introduces pyroprinting, a novel genotypic strain typing method that is rapid, inexpensive, and discriminating compared to the most sensitive methods already in use. Pyroprinting relies on the simultaneous pyrosequencing of polymorphic multicopy loci, such as the intergenic transcribed spacer regions of rRNA operons in bacterial genomes. Data generated by sequencing combinations of variable templates are reproducible and intrinsically digitized. The theory and development of pyroprinting in Escherichia coli, including the selection of similarity thresholds to define matches between isolates, are presented. The pyroprint-based strain differentiation limits and phylogenetic relevance compared to other typing methods are also explored. Pyroprinting is unique in its simplicity and, paradoxically, in its intrinsic complexity. This new approach serves as an excellent alternative to more cumbersome or less phylogenetically relevant strain typing methods. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Detoxification of mercury pollutant leached from spent fluorescent lamps using bacterial strains.

    Science.gov (United States)

    Al-Ghouti, Mohammad A; Abuqaoud, Reem H; Abu-Dieyeh, Mohammed H

    2016-03-01

    The spent fluorescent lamps (SFLs) are being classified as a hazardous waste due to having mercury as one of its main components. Mercury is considered the second most toxic heavy metal (arsenic is the first) with harmful effects on animal nervous system as it causes different neurological disorders. In this research, the mercury from phosphor powder was leached, then bioremediated using bacterial strains isolated from Qatari environment. Leaching of mercury was carried out with nitric and hydrochloric acid solutions using two approaches: leaching at ambient conditions and microwave-assisted leaching. The results obtained from this research showed that microwave-assisted leaching method was significantly better in leaching mercury than the acid leaching where the mercury leaching efficiency reached 76.4%. For mercury bio-uptake, twenty bacterial strains (previously isolated and purified from petroleum oil contaminated soils) were sub-cultured on Luria Bertani (LB) plates with mercury chloride to check the bacterial tolerance to mercury. Seven of these twenty strains showed a degree of tolerance to mercury. The bio-uptake capacities of the promising strains were investigated using the mercury leached from the fluorescent lamps. Three of the strains (Enterobacter helveticus, Citrobacter amalonaticus, and Cronobacter muytjensii) showed bio-uptake efficiency ranged from 28.8% to 63.6%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Characterization of rumen bacterial strains isolated from enrichments of rumen content in the presence of propolis.

    Science.gov (United States)

    de Aguiar, Sílvia Cristina; Zeoula, Lucia Maria; do Prado, Odimari Pricila Pires; Arcuri, Pedro Braga; Forano, Evelyne

    2014-11-01

    Propolis presents many biological properties, including antibacterial activities, and has been proposed as an additive in ruminant nutrition. Twenty bacterial strains, previously isolated from enrichments of Brazilian cow rumen contents in the presence of different propolis extracts (LLOS), were characterized using phenotyping and 16S rRNA identification. Seven strains were assigned to Streptococcus sp., most likely S. bovis, and were all degrading starch. One amylolytic lactate-utilizing strain of Selenomonas ruminantium was also found. Two strains of Clostridium bifermentans were identified and showed proteolytic activity. Two strains were assigned to Mitsuokella jalaludinii and were saccharolytic. One strain belonged to a Bacillus species and seven strains were affiliated with Escherichia coli. All of the 20 strains were able to use many sugars, but none of them were able to degrade the polysaccharides carboxymethylcellulose and xylans. The effect of three propolis extracts (LLOS B1, C1 and C3) was tested on the in vitro growth of four representative isolates of S. bovis, E. coli, M. jalaludinii and C. bifermentans. The growth of S. bovis, E. coli and M. jalaludinii was not affected by the three propolis extracts at 1 mg ml(-1). C. bifermentans growth was completely inhibited at this LLOS concentration, but this bacterium was partially resistant at lower concentrations. LLOS C3, with the lower concentration of phenolic compounds, was a little less inhibitory than B1 and C1 on this strain.

  11. Antimicrobial sensitivity and frequency of DRUG resistance among bacterial strains isolated from cancer patients

    International Nuclear Information System (INIS)

    Faiz, M.; Bashir, T.

    2004-01-01

    Blood stream infections (bacteremia) is potentially life threatening. Concomitant with a change in the incidence and epidemiology of infecting organisms, there has been an increase in resistance to many antibiotic compounds. The widespread emergence of resistance among bacterial pathogens has an impact on our ability to treat patients effectively. The changing spectrum of microbial pathogens and widespread emergence of microbial resistance to antibiotic drugs has emphasized the need to monitor the prevalence of resistance in these strains. In the present study frequency of isolation of clinically significant bacteria and their susceptibility and resistance pattern against a wide range of antimicrobial drugs from positive blood cultures collected during 2001-2003 was studied. A total of 102 consecutive isolates were found with 63% gram positive and 44% gram negative strains. The dominating pathogens were Staphylococcus aureus (51%), Streptococci (31%), Pseudomonas (40%), Proteus (13%), Klebsiella (13%). The isolated strains were tested against a wide range of antibiotics belonging to cephalosporins, aminoglycosides and quinolone derivative group by disk diffusion method. It has been observed that isolated strains among gram positive and negative strains showed different level of resistance against aminoglycosides and cephalosporin group of antibiotics with gram positives showing highest number and frequency of resistance against aminoglycosides (40-50%) and cephalosporins.(35-45%) whereas cephalosporins were found to be more effective against gram negatives with low frequency of resistant strains. Cabapenem and quinolone derivative drugs were found to be most effective among other groups in both gram positive and negative strains with 23-41% strains found sensitive to these two drugs. The frequency of sensitive strains against aminoglycoside and cephalosporin in gram negative and gram positive strains were found to be decreasing yearwise with a trend towards an

  12. Exposure to static magnetic field stimulates quorum sensing circuit in luminescent Vibrio strains of the Harveyi clade.

    Directory of Open Access Journals (Sweden)

    Adelfia Talà

    Full Text Available In this study, the evidence of electron-dense magnetic inclusions with polyhedral shape in the cytoplasm of Harveyi clade Vibrio strain PS1, a bioluminescent bacterium living in symbiosis with marine organisms, led us to investigate the behavior of this bacterium under exposure to static magnetic fields ranging between 20 and 2000 Gauss. When compared to sham-exposed, the light emission of magnetic field-exposed bacteria growing on solid medium at 18°C ±0.1°C was increased up to two-fold as a function of dose and growth phase. Stimulation of bioluminescence by magnetic field was more pronounced during the post-exponential growth and stationary phase, and was lost when bacteria were grown in the presence of the iron chelator deferoxamine, which caused disassembly of the magnetic inclusions suggesting their involvement in magnetic response. As in luminescent Vibrio spp. bioluminescence is regulated by quorum sensing, possible effects of magnetic field exposure on quorum sensing were investigated. Measurement of mRNA levels by reverse transcriptase real time-PCR demonstrated that luxR regulatory gene and luxCDABE operon coding for luciferase and fatty acid reductase complex were significantly up-regulated in magnetic field-exposed bacteria. In contrast, genes coding for a type III secretion system, whose expression was negatively affected by LuxR, were down-regulated. Up-regulation of luxR paralleled with down-regulation of small RNAs that mediate destabilization of luxR mRNA in quorum sensing signaling pathways. The results of experiments with the well-studied Vibrio campbellii strain BB120 (originally classified as Vibrio harveyi and derivative mutants unable to synthesize autoinducers suggest that the effects of magnetic fields on quorum sensing may be mediated by AI-2, the interspecies quorum sensing signal molecule.

  13. ANTIMICROBIAL POTENTIAL OF GARLIC AND OREGANO EXTRACTS AND ESSENTIAL OILS AGAINST DIFFERENT BACTERIAL STRAINS

    Directory of Open Access Journals (Sweden)

    Ionica Deliu

    2017-12-01

    Full Text Available The modern world is often concerned about the bacterial diseases and the diversity of treatment possibilities. The herbal medicines overreach the medical world because the less number of side effects than synthetic drugs and their low costs. In addition to conventional drugs, the natural remedies can solve exceptional health problems. In this study the antibacterial actions of ethanolic, methanolic and aqueous plant extracts (Allium sativum L. and Origanum vulgare L. were tested. Also, we tested the antimicrobial effects of garlic and oregano essential oils against three bacterial strains. The extracts were tested by diffusion method and certain variants were used. The antibacterial effects were read after 24h of incubation at 37°C. The most obvious effect was observed for oregano essential oil and the smallest growth inhibition was registered for aqueous extracts. The alcoholic extracts were more efficient after concentration by evaporation. The most sensitive bacterial strain was Staphylococcus aureus strain. However the Citrobacter freundii clinical strain had not so high sensitivity at plant extracts, we shall consider the plant extracts as a good alternative to synthetic drugs.

  14. Limited diffusive fluxes of substrate facilitate coexistence of two competing bacterial strains

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Or, D.; Smets, Barth F.

    2008-01-01

    . It has been proposed, but never unambiguously experimentally tested, that a low substrate diffusive flux would impact bacterial diversity, by promoting the coexistence between slow-growing bacteria and their potentially faster-growing competitors. We used a simple experimental system, based on a Petri...... dish and a perforated Teflon((R)) membrane to control diffusive fluxes of substrate (benzoate) whilst permitting direct observation of bacterial colonies. The system was inoculated with prescribed strains of Pseudomonas, whose growth was quantified by microscopic monitoring of the fluorescent proteins...

  15. Characterization and degradation potential of diesel-degrading bacterial strains for application in bioremediation.

    Science.gov (United States)

    Balseiro-Romero, María; Gkorezis, Panagiotis; Kidd, Petra S; Van Hamme, Jonathan; Weyens, Nele; Monterroso, Carmen; Vangronsveld, Jaco

    2017-10-03

    Bioremediation of polluted soils is a promising technique with low environmental impact, which uses soil organisms to degrade soil contaminants. In this study, 19 bacterial strains isolated from a diesel-contaminated soil were screened for their diesel-degrading potential, biosurfactant (BS) production, and biofilm formation abilities, all desirable characteristics when selecting strains for re-inoculation into hydrocarbon-contaminated soils. Diesel-degradation rates were determined in vitro in minimal medium with diesel as the sole carbon source. The capacity to degrade diesel range organics (DROs) of strains SPG23 (Arthobacter sp.) and PF1 (Acinetobacter oleivorans) reached 17-26% of total DROs after 10 days, and 90% for strain GK2 (Acinetobacter calcoaceticus). The amount and rate of alkane degradation decreased significantly with increasing carbon number for strains SPG23 and PF1. Strain GK2, which produced BSs and biofilms, exhibited a greater extent, and faster rate of alkane degradation compared to SPG23 and PF1. Based on the outcomes of degradation experiments, in addition to BS production, biofilm formation capacities, and previous genome characterizations, strain GK2 is a promising candidate for microbial-assisted phytoremediation of diesel-contaminated soils. These results are of particular interest to select suitable strains for bioremediation, not only presenting high diesel-degradation rates, but also other characteristics which could improve rhizosphere colonization.

  16. Bacterial strains diversity in Musa spp. phyllosphere with antifungal activity against Mycosphaerella fijiensis Morelet

    Directory of Open Access Journals (Sweden)

    Mileidy Cruz-Martín

    2016-01-01

    Full Text Available The search for alternatives to agricultural pesticides used for the management of black Sigatoka (Mycosphaerella fijiensis Morelet includes the selection of microorganisms strains with potential for the control of this pathogen. The objective of the work was to characterize bacterial strains isolated from the phylosphere of Musa spp. with antifungal effect against M. fijiensis. A morphological, cultural, physiological and molecular characterization of the strains was performed and the antifungal activity of these strains was quantified by dual culture. It was verified the diversity of bacteria with antifungal properties against M. fijiensis present in the phylosphere of Musa spp.  In addition, it was found that the phyllosphere of these crops can be used as a source of obtaining possible biological controls of M. fijiensis.   Keywords: bacteria, biocontrol, Black Sigatoka, epiphytes

  17. Metabolic fingerprinting of bacterial strains isolated from northern areas of Pakistan

    International Nuclear Information System (INIS)

    Zaheer, A.; Latif, Z.

    2017-01-01

    The diversity of Plant Growth Promoting Rhizobacteria (PGPR) in the rhizosphere plays a key role in the maintenance of sustainable agricultural system. In this study, samples were obtained from northern areas of Pakistan. Thirty bacterial strains were isolated, purified, characterized biochemically and subjected to the metabolic fingerprinting by performing nitrogen fixation, phosphate solubilization, protease, indole acetic acid (IAA) production, antibiotic susceptibility and heavy metal resistance test, lead acetate assay for the H2S production. Strains showing distinct characteristics were further characterized by 16S rDNA sequencing and characterized as Bacillus pumilus (KT273321), Acinetobacter baumanii (KT273323), Acinetobacter junii (KT273324), Pseudomonas aeruginosa (KT273325), Bacillus circulans (KT273326) and Bacillus cereus (KT273327). As most of the strains show positive results for resistance against heavy metals, phosphate solubilization, nitrogen fixation, IAA production, and so these strains might be utilized for the removal of heavy metals from the ecosystem as well as biofertilizer in agriculture lands of northern areas. (author)

  18. A rapid colorimetric screening method for vanillic acid and vanillin-producing bacterial strains.

    Science.gov (United States)

    Zamzuri, N A; Abd-Aziz, S; Rahim, R A; Phang, L Y; Alitheen, N B; Maeda, T

    2014-04-01

    To isolate a bacterial strain capable of biotransforming ferulic acid, a major component of lignin, into vanillin and vanillic acid by a rapid colorimetric screening method. For the production of vanillin, a natural aroma compound, we attempted to isolate a potential strain using a simple screening method based on pH change resulting from the degradation of ferulic acid. The strain Pseudomonas sp. AZ10 UPM exhibited a significant result because of colour changes observed on the assay plate on day 1 with a high intensity of yellow colour. The biotransformation of ferulic acid into vanillic acid by the AZ10 strain provided the yield (Yp/s ) and productivity (Pr ) of 1·08 mg mg(-1) and 53·1 mg L(-1) h(-1) , respectively. In fact, new investigations regarding lignin degradation revealed that the strain was not able to produce vanillin and vanillic acid directly from lignin; however, partially digested lignin by mixed enzymatic treatment allowed the strain to produce 30·7 mg l(-1) and 1·94 mg l(-1) of vanillic acid and biovanillin, respectively. (i) The rapid colorimetric screening method allowed the isolation of a biovanillin producer using ferulic acid as the sole carbon source. (ii) Enzymatic treatment partially digested lignin, which could then be utilized by the strain to produce biovanillin and vanillic acid. To the best of our knowledge, this is the first study reporting the use of a rapid colorimetric screening method for bacterial strains producing vanillin and vanillic acid from ferulic acid. © 2013 The Society for Applied Microbiology.

  19. Synergism between hydrogen peroxide and seventeen acids against six bacterial strains.

    Science.gov (United States)

    Martin, H; Maris, P

    2012-09-01

    The objective of this study was to evaluate the bactericidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains were reference strains and strains representative of contaminating bacteria in the food industry. Each synergistic hydrogen peroxide/acid combination found after 5-min contact time at 20°C in distilled water was then tested in conditions simulating four different use conditions. Thirty-two combinations were synergistic in distilled water; twenty-five of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination was synergistic for all six bacterial strains in distilled water and remained synergistic with interfering substances. Six other combinations maintained their synergistic effect in the presence of an organic load but only for one or two bacterial strains. Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. A rapid screening method was proposed and used to reveal the synergistic potential of disinfectant and/or sanitizer combinations. © 2012 ANSES Fougères Laboratory Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  20. [Characterization of a bacterial biocontrol strain 1404 and its efficacy in controlling postharvest citrus anthracnose].

    Science.gov (United States)

    Wang, Qian; Hu, Chunjin; Ke, Fanggang; Huang, Siliang; Li, Qiqin

    2010-09-01

    Anthracnose caused by Colletotrichum gloeosporioides (Penz.) Sacc. is a main disease in citrus production. To develop an effective biocontrol measure against citrus postharvest anthracnose, we screened antagonistic microbes and obtained a bacterial strain 1404 from the rhizospheric soil of chili plants in Nanning city, Guangxi, China. The objectives of the present study were to: (1) identify and characterize the antagonistic bacterium; and (2) to evaluate the efficacy of the antagonistic strain in controlling citrus postharvest anthracnose disease. Strain 1404 was identified by comparing its 16S rDNA sequence with related bacteria from GenBank database, as well as analyzing its morphological, physiological and biochemical characters. The antagonistic stability of the strain 1404 was determined by continuously transferring it on artificial media. The effect of the strain on suppressing citrus anthracnose at postharvest stage was tested by stab inoculation method. The 16S rDNA of strain 1404 was amplified with primers PF1 (5'-AGAGTTTGATCATGGCTCAG-3') and PR1 (5'-TACGGTTACCTTGTTACGACTT-3') and its sequence submitted to GenBank (accession number: GU361113). Strain 1404 clustered with the GenBank-derived Brevibacillus brevis strains in the 16S-rDNA-sequence-based phylogenetic tree at 100% bootstrap level. The morphological traits, physiological and biochemical characters of strain 1404 agreed with that of Brevibacillus brevis. Less change in the suppressive ability of antagonist against growth of Colletotrichum gloeosporioides was observed during four continuous transfers on artificial media. The average control efficacy of the strain was 64. 9 % against the disease 20 days after the antagonist application. Strain 1404 was identified as Brevibacillus brevis based on its morphological traits, phyiological and biochemical characters as well as 16S rDNA sequence analysis. The antagonist was approved to be a promising biocontrol agent. This is the first report of

  1. Distinct Bacterial Composition Associated with Different Laboratory-cultured Aiptasia Strains Across Two Thermal Conditions

    KAUST Repository

    Ahmed, Hanin

    2018-05-01

    Coral reefs are crucial for the ecological sustainability of the oceans, yet, increasing sea surface temperature is threatening these ecosystems globally. Microbial communities associated with corals have become a recent research focus, as the associated microbiome may contribute to coral resilience to environmental stressors, e.g., heat stress. However, research in this area is hampered by the difficulty of working with corals. This study aims to use Aiptasia, a sea anemone, as a tractable laboratory model system to study the role of the coral microbiome. Analyses of the bacterial compositions associated with different Aiptasia strains across two temperatures (25 °C and 32 °C), based on 16S rRNA gene sequencing. This study aims also to identify a “core” microbiome associated with heat stress acclimation, as well as host-specific differences. In general, results showed that bacterial composition associated with Aiptasia strains differs significantly with temperature. Higher bacterial diversity and richness were observed when all Aiptasia strains were placed under heat stress. Moreover, results showed an increase in beta diversity and dispersion of bacterial communities in response to heat stress. These changes in the bacterial composition are in line with the recently described “Anna Karenina principle” for animal microbiomes, which suggests that the microbiomes of unhealthy individuals vary more than healthy and stable individuals. This study further shows that while temperature had the greatest effect on structuring the bacterial compositions, there were some variations better attributed to batch and host effects. This suggests that technical aspects have to be carefully addressed in the framework of microbiome studies. Members of a putative “core” microbiome associated with 32 °C Aiptasia have been identified as indicator species of heat stress (i.e., Francisella sp.,). Previous reports have shown that these indicator taxa are associated with

  2. Effects of Bacterial Strains to Inhibit Growth of Phytophthora pistaciae under Different Electrical Conductivities

    Directory of Open Access Journals (Sweden)

    Moslem Hajabdolahi

    2018-06-01

    Full Text Available Root and crown rot (gummosis is known as the most destructive disease affecting pistachio in Iran. The efficiency of bacterial strains to reduce the growth rate of Phytophthora pistaciae was studied under different electrical conductivities (EC, 0, 2, 4, 8, 12 ds/m. Soil and rhizosphere samples were collected from pistachio growing regions in Kerman province, Iran, during 2011 - 2012. Overall, the strains of bacteria were presented in all sampling areas in both infected and uninfected orchards. Out of 400 bacterial isolates, 63% and 37% were collected from soil and rhizosphere samples, respectively. Among 400 bacterial isolates, 19 exhibited the highest ability to reduce the growth of P. pistaciae in dual culture, volatile and non-volatile compounds, though by different degrees. The degrees of inhibitory activities against mycelial growth of P. pistaciae by Pseudomonas fluorescens strains ranged from 40 to 97.5%, 8 to 97.5% and 7.5 to 90% in dual culture, non-volatile and volatile assays, respectively. The Bacillus subtilis strains reduced the growth of P. pistaciae by 22-92.5%, 17-85%, 21-92.5% in dual culture, non-volatile and volatile assays, respectively. The negative effects of ECs on the growth of P. pistaciae in modified CMA were observed in 8 and 12 ECs. ECs had no effect until 8 ds/m on the growth of P. pistaciae, while the mycelial growth decreased by ECs higher than 8 ds/m. No mycelial growth was observed at EC 14 ds/m. There were significant differences between different bacterial isolates, ECs and their interactions on the mycelial growth of P. pistaciae. The highest mycelial suppression belonged to isolates Nos. 123 and 112 in dual culture, volatile and non-volatile compounds test. More research is required to understand the native mechanisms involved in biological control under natural conditions in pistachio orchards

  3. Eradication of the corrosion-causing bacterial strains Desulfovibrio vulgaris and Desulfovibrio desulfuricans using photodisinfection

    Energy Technology Data Exchange (ETDEWEB)

    Street, C.N.; Gibbs, A.J. [Biocorrosion Solutions Inc., Edmonton, AB (Canada)

    2010-07-01

    Microbiologically influenced corrosion (MIC) can cause oil and gas pipelines to fail prematurely. The free-floating bacteria collects on the inner pipeline surface to form complex adherent biofilms. This study evaluated the use of photodisinfection as a means of treating 2 sulfate-reducing bacterial strains known to contribute to MIC. The sulfate-reducing strains Desulfovibrio vulgaris and Desulfovibrio desulfuricans were studied experimentally to a concentration of 10{sup 7} colony-forming units per millimeter. Bacterial inocula was made to an optical density of 0.150 at 420 nm in order to assess biofilm growth. The study showed that photodisinfection was able to eradicate more than 99 per cent of the bacterial populations prepared in the study. The method was highly effective in removing the biofilms known to cause MIC in oil and gas pipelines. A close-loop dynamic flow system model will be prepared to evaluate the ability of photodisinfection to inhibit bacterially-influenced corrosion of steel coupons. 24 refs., 3 tabs., 1 fig.

  4. Band-gap engineering by molecular mechanical strain-induced giant tuning of the luminescence in colloidal amorphous porous silicon nanostructures.

    Science.gov (United States)

    Mughal, A; El Demellawi, J K; Chaieb, Sahraoui

    2014-12-14

    Nano-silicon is a nanostructured material in which quantum or spatial confinement is the origin of the material's luminescence. When nano-silicon is broken into colloidal crystalline nanoparticles, its luminescence can be tuned across the visible spectrum only when the sizes of the nanoparticles, which are obtained via painstaking filtration methods that are difficult to scale up because of low yield, vary. Bright and tunable colloidal amorphous porous silicon nanostructures have not yet been reported. In this letter, we report on a 100 nm modulation in the emission of freestanding colloidal amorphous porous silicon nanostructures via band-gap engineering. The mechanism responsible for this tunable modulation, which is independent of the size of the individual particles and their distribution, is the distortion of the molecular orbitals by a strained silicon-silicon bond angle. This mechanism is also responsible for the amorphous-to-crystalline transformation of silicon.

  5. Band-gap engineering by molecular mechanical strain-induced giant tuning of the luminescence in colloidal amorphous porous silicon nanostructures

    KAUST Repository

    Mughal, Asad Jahangir

    2014-01-01

    Nano-silicon is a nanostructured material in which quantum or spatial confinement is the origin of the material\\'s luminescence. When nano-silicon is broken into colloidal crystalline nanoparticles, its luminescence can be tuned across the visible spectrum only when the sizes of the nanoparticles, which are obtained via painstaking filtration methods that are difficult to scale up because of low yield, vary. Bright and tunable colloidal amorphous porous silicon nanostructures have not yet been reported. In this letter, we report on a 100 nm modulation in the emission of freestanding colloidal amorphous porous silicon nanostructures via band-gap engineering. The mechanism responsible for this tunable modulation, which is independent of the size of the individual particles and their distribution, is the distortion of the molecular orbitals by a strained silicon-silicon bond angle. This mechanism is also responsible for the amorphous-to-crystalline transformation of silicon. This journal is

  6. Regional analysis of potential polychlorinated biphenyl degrading bacterial strains from China

    Directory of Open Access Journals (Sweden)

    Jianjun Shuai

    Full Text Available ABSTRACT Polychlorinated biphenyls (PCBs, the chlorinated derivatives of biphenyl, are one of the most prevalent, highly toxic and persistent groups of contaminants in the environment. The objective of this study was to investigate the biodegradation of PCBs in northeastern (Heilongjiang Province, northern (Shanxi Province and eastern China (Shanghai municipality. From these areas, nine soil samples were screened for PCB-degrading bacteria using a functional complementarity method. The genomic 16S rDNA locus was amplified and the products were sequenced to identify the bacterial genera. Seven Pseudomonas strains were selected to compare the capacity of bacteria from different regions to degrade biphenyl by HPLC. Compared to the biphenyl content in controls of 100%, the biphenyl content went down to 3.7% for strain P9-324, 36.3% for P2-11, and 20.0% for the other five strains. These results indicate that a longer processing time led to more degradation of biphenyl. PCB-degrading bacterial strains are distributed differently in different regions of China.

  7. Effect of Aqueous Garlic Extract (AGE) and gamma irradiation on some Bacterial Strains

    International Nuclear Information System (INIS)

    Awny, N.M; Tawfik, Z.S; Abu Nor, S.M; El-Saled, K.M.

    2005-01-01

    In the present study the sensitivity of four bacterial strains; Salmonella typhimurium, Escherichia coli, Bacillus subtilis and Bacillus pumilus were tested towards the antibacterial effect of aqueous garlic extract (AGE) with different concentration. The results indicated that, the Gram positive spore forming strains, Bacillus subtilis and Bacillus pumilus treated with AGE from 0 to 70μ1/m1 were more resistant than Gram negative non-spore forming ones, Salmonella typhimurium and Escherichia coli treated with AGE from 0 to 24 μ1/m1. The effect of AGE treatment on the radiosensitivity of the tested bacterial strains showed that, AGE treatment before γ-irradiation induced a higher protection than treatment immediately after γ-irradiation. The ultrastructure configuration of untreated strains, treated with AGE or irradiation and combination between AGE and Irradiation, were investigated using transmission electron microscope (TEM). The results indicated that, ultra-structures configuration of the cells treated with AGE before irradiation appeared with less damage than those of cells irradiated without AGE treatment

  8. Screening of bacterial strains for pectinolytic activity: characterization of the polygalacturonase produced by Bacillus sp

    Directory of Open Access Journals (Sweden)

    Soares Márcia M.C.N.

    1999-01-01

    Full Text Available One hundred sixty eight bacterial strains, isolated from soil and samples of vegetable in decomposition, were screened for the use of citrus pectin as the sole carbon source. 102 were positive for pectinase depolymerization in assay plates as evidenced by clear hydrolization halos. Among them, 30% presented considerable pectinolytic activity. The cultivation of these strains by submerged and semi-solid fermentation for polygalacturonase production indicated that five strains of Bacillus sp produced high quantities of the enzyme. The physico-chemical characteristics, such as optimum pH of 6.0 - 7.0, optimum temperatures between 45oC and 55oC, stability at temperatures above 40oC and in neutral and alkaline pH, were determined.

  9. Antibacterial activity of fumaria indica (hausskn.) pugsley against selected bacterial strains

    International Nuclear Information System (INIS)

    Toor, Y.; Nawaz, K.; Hussain, K.

    2015-01-01

    Antibacterial properties of methanolic extracts of F. indica prepared in different doses against seven Gram-positive and Gram-negative bacterial strains i.e. Streptococcus pyogenes, Staphylococcus aureus (1), Staphylococcus aureus (2), Shigella sonnei, Escherichia coli (1), Escherichia coli (2) and Neisseria gonorrhoeae using agar well diffusion method (inhibition zone measurements) compared to gentamicin as standard antibiotic. Results showed significant activities against the test organisms with overall satisfactory statistics. Streptococcus pyogenes, Staphylococcus aureus strains as well as Neisseria gonorrhoeae showed more inhibition to methanolic extracts of F. indica. Minimum inhibitory as well as minimum bactericidal concentrations against all strains except Shigella sonnei were also recorded. Studies showed promising horizons for the use of F. indica as an active antibacterial component in modern drug formulations. (author)

  10. Identification of bacterial strains isolated from the Mediterranean Sea exhibiting different abilities of biofilm formation.

    Science.gov (United States)

    Brian-Jaisson, Florence; Ortalo-Magné, Annick; Guentas-Dombrowsky, Linda; Armougom, Fabrice; Blache, Yves; Molmeret, Maëlle

    2014-07-01

    The Mediterranean Sea has rarely been investigated for the characterization of marine bacteria as compared to other marine environments such as the Atlantic or Pacific Ocean. Bacteria recovered from inert surfaces are poorly studied in these environments, when it has been shown that the community structure of attached bacteria can be dissimilar from that of planktonic bacteria present in the water column. The objectives of this study were to identify and characterize marine bacteria isolated from biofilms developed on inert surfaces immersed in the Mediterranean Sea and to evaluate their capacity to form a biofilm in vitro. Here, 13 marine bacterial strains have been isolated from different supports immersed in seawater in the Bay of Toulon (France). Phylogenetic analysis and different biological and physico-chemical properties have been investigated. Among the 13 strains recovered, 8 different genera and 12 different species were identified including 2 isolates of a novel bacterial species that we named Persicivirga mediterranea and whose genus had never been isolated from the Mediterranean Sea. Shewanella sp. and Pseudoalteromonas sp. were the most preponderant genera recovered in our conditions. The phenotypical characterization revealed that one isolate belonging to the Polaribacter genus differed from all the other ones by its hydrophobic properties and poor ability to form biofilms in vitro. Identifying and characterizing species isolated from seawater including from Mediterranean ecosystems could be helpful for example, to understand some aspects of bacterial biodiversity and to further study the mechanisms of biofilm (and biofouling) development in conditions approaching those of the marine environment.

  11. Spatial variation in deposition rate coefficients of an adhesion-deficient bacterial strain in quartz sand.

    Science.gov (United States)

    Tong, Meiping; Camesano, Terri A; Johnson, William P

    2005-05-15

    The transport of bacterial strain DA001 was examined in packed quartz sand under a variety of environmentally relevant ionic strength and flow conditions. Under all conditions, the retained bacterial concentrations decreased with distance from the column inlet at a rate that was faster than loglinear, indicating that the deposition rate coefficient decreased with increasing transport distance. The hyperexponential retained profile contrasted againstthe nonmonotonic retained profiles that had been previously observed for this same bacterial strain in glass bead porous media, demonstrating that the form of deviation from log-linear behavior is highly sensitive to system conditions. The deposition rate constants in quartz sand were orders of magnitude below those expected from filtration theory, even in the absence of electrostatic energy barriers. The degree of hyperexponential deviation of the retained profiles from loglinear behavior did not decrease with increasing ionic strength in quartz sand. These observations demonstrate thatthe observed low adhesion and deviation from log-linear behavior was not driven by electrostatic repulsion. Measurements of the interaction forces between DA001 cells and the silicon nitride tip of an atomic force microscope (AFM) showed that the bacterium possesses surface polymers with an average equilibrium length of 59.8 nm. AFM adhesion force measurements revealed low adhesion affinities between silicon nitride and DA001 polymers with approximately 95% of adhesion forces having magnitudes responsible for the low adhesion to silicon nitride, indicating that steric interactions from extracellular polymers controlled DA001 adhesion deficiency and deviation from log-linear behavior on quartz sand.

  12. Conductivity-Dependent Strain Response of Carbon Nanotube Treated Bacterial Nanocellulose

    Directory of Open Access Journals (Sweden)

    S. Farjana

    2013-01-01

    Full Text Available This paper reports the strain sensitivity of flexible, electrically conductive, and nanostructured cellulose which was prepared by modification of bacterial cellulose with double-walled carbon nanotubes (DWCNTs and multiwalled carbon nanotubes (MWCNTs. The electrical conductivity depends on the modifying agent and its dispersion process. The conductivity of the samples obtained from bacterial cellulose (BNC pellicles modified with DWCNT was in the range from 0.034 S·cm−1 to 0.39 S·cm−1, and for BNC pellicles modified with MWCNTs it was from 0.12 S·cm−1 to 1.6 S·cm−1. The strain-induced electromechanical response, resistance versus strain, was monitored during the application of tensile force in order to study the sensitivity of the modified nanocellulose. A maximum gauge factor of 252 was found from the highest conductive sample treated by MWCNT. It has been observed that the sensitivity of the sample depends on the conductivity of the modified cellulose.

  13. Hexavalent chromium reduction by bacterial consortia and pure strains from an alkaline industrial effluent.

    Science.gov (United States)

    Piñón-Castillo, H A; Brito, E M S; Goñi-Urriza, M; Guyoneaud, R; Duran, R; Nevarez-Moorillon, G V; Gutiérrez-Corona, J F; Caretta, C A; Reyna-López, G E

    2010-12-01

    To characterize the bacterial consortia and isolates selected for their role in hexavalent chromium removal by adsorption and reduction. Bacterial consortia from industrial wastes revealed significant Cr(VI) removal after 15 days when incubated in medium M9 at pH 6·5 and 8·0. The results suggested chromium reduction. The bacterial consortia diversity (T-RFLP based on 16S rRNA gene) indicated a highest number of operational taxonomic units in an alkaline carbonate medium mimicking in situ conditions. However, incubations under such conditions revealed low Cr(VI) removal. Genomic libraries were obtained for the consortia exhibiting optimal Cr(VI) removal (M9 medium at pH 6·5 and 8·0). They revealed the dominance of 16S rRNA gene sequences related to the genera Pseudomonas/Stenotrophomonas or Enterobacter/Halomonas, respectively. Isolates related to Pseudomonas fluorescens and Enterobacter aerogenes were efficient in Cr(VI) reduction and adsorption to the biomass. Cr(VI) reduction was better at neutral pH rather than under in situ conditions (alkaline pH with carbonate). Isolated strains exhibited significant capacity for Cr(VI) reduction and adsorption. Bacterial communities from chromium-contaminated industrial wastes as well as isolates were able to remove Cr(VI). The results suggest a good potential for bioremediation of industrial wastes when optimal conditions are applied. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology. No claim to Mexican Government works.

  14. Programmable removal of bacterial strains by use of genome-targeting CRISPR-Cas systems.

    Science.gov (United States)

    Gomaa, Ahmed A; Klumpe, Heidi E; Luo, Michelle L; Selle, Kurt; Barrangou, Rodolphe; Beisel, Chase L

    2014-01-28

    CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems in bacteria and archaea employ CRISPR RNAs to specifically recognize the complementary DNA of foreign invaders, leading to sequence-specific cleavage or degradation of the target DNA. Recent work has shown that the accidental or intentional targeting of the bacterial genome is cytotoxic and can lead to cell death. Here, we have demonstrated that genome targeting with CRISPR-Cas systems can be employed for the sequence-specific and titratable removal of individual bacterial strains and species. Using the type I-E CRISPR-Cas system in Escherichia coli as a model, we found that this effect could be elicited using native or imported systems and was similarly potent regardless of the genomic location, strand, or transcriptional activity of the target sequence. Furthermore, the specificity of targeting with CRISPR RNAs could readily distinguish between even highly similar strains in pure or mixed cultures. Finally, varying the collection of delivered CRISPR RNAs could quantitatively control the relative number of individual strains within a mixed culture. Critically, the observed selectivity and programmability of bacterial removal would be virtually impossible with traditional antibiotics, bacteriophages, selectable markers, or tailored growth conditions. Once delivery challenges are addressed, we envision that this approach could offer a novel means to quantitatively control the composition of environmental and industrial microbial consortia and may open new avenues for the development of "smart" antibiotics that circumvent multidrug resistance and differentiate between pathogenic and beneficial microorganisms. Controlling the composition of microbial populations is a critical aspect in medicine, biotechnology, and environmental cycles. While different antimicrobial strategies, such as antibiotics, antimicrobial peptides, and lytic bacteriophages, offer partial solutions

  15. Seaweed as source of energy. 1: effect of a specific bacterial strain on biogas production

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivasa R.P.; Tarwade, S.J.; Sarma, K.S.R.

    1980-09-01

    Only certain marine bacteria capable of digesting the special type of polysaccharide - agar and alginic acid can bring about the biodegradation of these substances and utilise them as carbon source to produce the organics which will be utilised by the methane bacteria to produce methane. When bacterial strain was used in conjunction with cowdung as a source of methane bacteria in seaweed digester, production of biogas from seaweed was accelerated. Adding of small amount of Ulva to seaweed digester increased the output of gas. (Refs. 4).

  16. Bioremediation of crude oil polluted seawater by a hydrocarbon-degrading bacterial strain immobilized on chitin and chitosan flakes

    International Nuclear Information System (INIS)

    Gentili, A.R.; Cubitto, M.A.; Ferrero, M.; Rodriguez, M.S.

    2006-01-01

    In this laboratory-scale study, we examined the potential of chitin and chitosan flakes obtained from shrimp wastes as carrier material for a hydrocarbon-degrading bacterial strain. Flakes decontamination, immobilization conditions and the survival of the immobilized bacterial strain under different storage temperatures were evaluated. The potential of immobilized hydrocarbon-degrading bacterial strain for crude oil polluted seawater bioremediation was tested in seawater microcosms. In terms of removal percentage of crude oil after 15 days, the microcosms treated with the immobilized inoculants proved to be the most successful. The inoculants formulated with chitin and chitosan as carrier materials improved the survival and the activity of the immobilized strain. It is important to emphasize that the inoculants formulated with chitin showed the best performance during storage and seawater bioremediation. (author)

  17. Isolation, screening and molecular identification of novel bacterial strain removing methylene blue from water solutions

    Science.gov (United States)

    Kilany, Mona

    2017-11-01

    The potentially deleterious effects of methylene blue (MB) on human health drove the interest in its removal promptly. Bioremediation is an effective and eco friendly for removing MB. Soil bacteria were isolated and examined for their potential to remove MB. The most potent bacterial candidate was characterized and identified using 16S rRNA sequence technique. The evolutionary history of the isolate was conducted by maximum likelihood method. Some physiochemical parameters were optimized for maximum decolorization. Decolorization mechanism and microbial toxicity study of MB (100 mg/l) and by-products were investigated. Participation of heat killed bacteria in color adsorption have been investigated too. The bacterial isolate was identified as Stenotrophomonas maltophilia strain Kilany_MB 16S ribosomal RNA gene with 99% sequence similarity. The sequence was submitted to NCBI (Accession number = KU533726). Phylogeny depicted the phylogenetic relationships between 16S ribosomal RNA gene, partial sequence (1442 bp), of the isolated strain and other strains related to Stenotrophomonas maltophilia in the GenBank database. The optimal conditions were investigated to be pH 5 at 30 °C, after 24 h using 5 mg/l MB showing optimum decolorization percentage (61.3%). Microbial toxicity study demonstrated relative reduction in the toxicity of MB decolorized products on test bacteria. Mechanism of color removal was proved by both biosorption and biodegradation, where heat-killed and live cells showed 43 and 52% of decolorization, respectively, as a maximum value after 24-h incubation. It was demonstrated that the mechanism of color removal is by adsorption. Therefore, good performance of S maltophilia in MB color removal reinforces the exploitation of these bacteria in environmental clean-up and restoration of the ecosystem.

  18. Evaluation of indigenous bacterial strains for biocontrol of the frogeye leaf spot of soya bean caused by Cercospora sojina.

    Science.gov (United States)

    Simonetti, E; Carmona, M A; Scandiani, M M; García, A F; Luque, A G; Correa, O S; Balestrasse, K B

    2012-08-01

    Assessment of biological control of Cercospora sojina, causal agent of frogeye leaf spot (FLS) of soya bean, using three indigenous bacterial strains, BNM297 (Pseudomonas fluorescens), BNM340 and BNM122 (Bacillus amyloliquefaciens). From cultures of each bacterial strain, cell suspensions and cell-free supernatants were obtained and assayed to determine their antifungal activity against C. sojina. Both mycelial growth and spore germination in vitro were more strongly inhibited by bacterial cell suspensions than by cell-free supernatants. The Bacillus strains BNM122 and BNM340 inhibited the fungal growth to a similar degree (I ≈ 52-53%), while cells from P. fluorescens BNM297 caused a lesser reduction (I ≈ 32-34%) in the fungus colony diameter. The foliar application of the two Bacillus strains on soya bean seedlings, under greenhouse conditions, significantly reduced the disease severity with respect to control soya bean seedlings and those sprayed with BNM297. This last bacterial strain was not effective in controlling FLS in vivo. Our data demonstrate that the application of antagonistic bacteria may be a promising and environmentally friendly alternative to control the FLS of soya bean.   To our knowledge, this is the first report of biological control of C. sojina by using native Bacillus strains. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

  19. Pathogenicity of a Very Virulent Strain of Marek's Disease Herpesvirus Cloned as Infectious Bacterial Artificial Chromosomes

    Directory of Open Access Journals (Sweden)

    Lorraine P. Smith

    2011-01-01

    Full Text Available Bacterial artificial chromosome (BAC vectors containing the full-length genomes of several herpesviruses have been used widely as tools to enable functional studies of viral genes. Marek's disease viruses (MDVs are highly oncogenic alphaherpesviruses that induce rapid-onset T-cell lymphomas in chickens. Oncogenic strains of MDV reconstituted from BAC clones have been used to examine the role of viral genes in inducing tumours. Past studies have demonstrated continuous increase in virulence of MDV strains. We have previously reported on the UK isolate C12/130 that showed increased virulence features including lymphoid organ atrophy and enhanced tropism for the central nervous system. Here we report the construction of the BAC clones (pC12/130 of this strain. Chickens were infected with viruses reconstituted from the pC12/130 clones along with the wild-type virus for the comparison of the pathogenic properties. Our studies show that BAC-derived viruses induced disease similar to the wild-type virus, though there were differences in the levels of pathogenicity between individual viruses. Generation of BAC clones that differ in the potential to induce cytolytic disease provide the opportunity to identify the molecular determinants of increased virulence by direct sequence analysis as well as by using reverse genetics approaches on the infectious BAC clones.

  20. [Co-occurence of indol-producing bacterial strains in the vagina of women infected with Chlamydia trachomatis].

    Science.gov (United States)

    Romanik, Małgorzata; Martirosian, Gayane; Wojciechowska-Wieja, Anna; Cieślik, Katarzyna; Kaźmierczak, Wojciech

    2007-08-01

    The aim of this study was to determine if cervicitis, caused by Chlamydia trachomatis (C. trachomatis), has an influence on the frequency of occurrence of selected aerobic and anaerobic bacterial strains, connected with etiology of aerobic vaginitis (AV) and bacterial vaginosis (BV). Indole-producing bacteria have received particular attention due to their possibly inductive role in chronic cervicitis caused by C. trachomatis. The swabs from vagina and cervical canal have been obtained from 122 women (aged 18-40). The presence of C. trachomatis antigen had been detected and diagnosed with the help of direct immunofluorescence, BV with Amesl and Nugent criteria, whereas the AV with Donders criteria. The identification of the bacterial strains isolated from vagina has been performed according to classical microbiological diagnostics. Disruption of vaginal microflora (4-10 in Nugent score) was determined in 11,5% of observed women. AV was diagnosed in 4.5% women with chlamydial cervicitis, BV was diagnosed in 10.9% and 5.45% of these women, on the basis of Amsel and Nugent criteria respectively. Indole-producing bacterial strains connected with BV and AV (Peptostreptococcus anaerobius, Propionibacterium acnes, Escherichia coli) have been isolated significantly more often from vagina of women infected with C trachomatis (p = 0.0405, chi2 = 4.20) and these findings confirm co-importance of indole-producing bacterial strains in cervicitis caused by C trachomatis .

  1. Identification of thermophilic bacterial strains producing thermotolerant hydrolytic enzymes from manure compost.

    Science.gov (United States)

    Charbonneau, David M; Meddeb-Mouelhi, Fatma; Boissinot, Maurice; Sirois, Marc; Beauregard, Marc

    2012-03-01

    Ten thermophilic bacterial strains were isolated from manure compost. Phylogenetic analysis based on 16S rRNA genes and biochemical characterization allowed identification of four different species belonging to four genera: Geobacillus thermodenitrificans, Bacillus smithii, Ureibacillus suwonensis and Aneurinibacillus thermoaerophilus. PCR-RFLP profiles of the 16S-ITS-23S rRNA region allowed us to distinguish two subgroups among the G. thermodenitrificans isolates. Isolates were screened for thermotolerant hydrolytic activities (60-65°C). Thermotolerant lipolytic activities were detected for G. thermodenitrificans, A. thermoaerophilus and B. smithii. Thermotolerant protease, α-amylase and xylanase activities were also observed in the G. thermodenitrificans group. These species represent a source of potential novel thermostable enzymes for industrial applications.

  2. Seaweed as source of energy. I: effect of a specific bacterial strain on biogas production

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P.S.; Tarwade, S.J.; Sarma, K.S.R.

    1980-01-01

    Biogas was produced from seaweed by making use of alginate-digesting marine bacteria that were isolated from decomposing seaweed and can digest seaweed carbohydrates (agar and alginic acid). Laboratory digesters containing 100 g seaweed were inoculated with 50 mL broth cultures of different seaweed-derived bacterial strains, and the maximum amount of degradation obtained was 28% (compared with 13% for a bacteria-free digestion). Cow dung was added as a source of methanogenic bacteria, and the amount of biogas produced was more than double the amount obtained when seaweed and cow dung were digested in the absence of the seaweed-derived bacteria. Adding a small amount of Ulva to the seaweed digester increased the production of biogas.

  3. A nonluminescent and highly virulent Vibrio harveyi strain is associated with "bacterial white tail disease" of Litopenaeus vannamei shrimp.

    Directory of Open Access Journals (Sweden)

    Junfang Zhou

    Full Text Available Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by "white tail" and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905 was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN, white tail disease (WTD or penaeid white tail disease (PWTD. To differentiate from such diseases as with a sign of "white tail" but of non-bacterial origin, the present disease was named as "bacterial white tail disease (BWTD". Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system.

  4. Bio-degradation of oily food waste employing thermophilic bacterial strains.

    Science.gov (United States)

    Awasthi, Mukesh Kumar; Selvam, Ammaiyappan; Chan, Man Ting; Wong, Jonathan W C

    2018-01-01

    The objective of this work was to isolate a novel thermophilic bacterial strain and develop a bacterial consortium (BC) for efficient degradation oily food waste. Four treatments were designed: 1:1 mixture of pre-consumption food wastes (PrCFWs) and post-consumption food wastes (PCFWs) (T-1), 1:2 mixture of PrCFWs and PCFWs mixture (T-2), PrCFWs (T-3) and PCFWs (T-4). Equal quantity of BC was inoculated into each treatment to compare the oil degradation efficiency. Results showed that after 15days of incubation, a maximum oil reduction of 65.12±0.08% was observed in treatment T-4, followed by T-2 (55.44±0.12%), T-3 (54.79±0.04%) and T-1 (52.52±0.02%), while oil reduction was negligible in control. Results indicate that the development of oil utilizing thermophilic BC was more cost-effective in solving the degradation of oily food wastes and conversion into a stable end product. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The effect of rhamnolipid biosurfactant produced by Pseudomonas fluorescens on model bacterial strains and isolates from industrial wastewater.

    Science.gov (United States)

    Vasileva-Tonkova, Evgenia; Sotirova, Anna; Galabova, Danka

    2011-02-01

    In this study, the effect of rhamnolipid biosurfactant produced by Pseudomonas fluorescens on bacterial strains, laboratory strains, and isolates from industrial wastewater was investigated. It was shown that biosurfactant, depending on the concentration, has a neutral or detrimental effect on the growth and protein release of model Gram (+) strain Bacillus subtilis 168. The growth and protein release of model Gram (-) strain Pseudomonas aeruginosa 1390 was not influenced by the presence of biosurfactant in the medium. Rhamnolipid biosurfactant at the used concentrations supported the growth of some slow growing on hexadecane bacterial isolates, members of the microbial community. Changes in cell surface hydrophobicity and permeability of some Gram (+) and Gram (-) isolates in the presence of rhamnolipid biosurfactant were followed in experiments in vitro. It was found that bacterial cells treated with biosurfactant became more or less hydrophobic than untreated cells depending on individual characteristics and abilities of the strains. For all treated strains, an increase in the amount of released protein was observed with increasing the amount of biosurfactant, probably due to increased cell permeability as a result of changes in the organization of cell surface structures. The results obtained could contribute to clarify the relationships between members of the microbial community as well as suggest the efficiency of surface properties of rhamnolipid biosurfactant from Pseudomonas fluorescens making it potentially applicable in bioremediation of hydrocarbon-polluted environments.

  6. Occurrence of Antibiotic resistance in some bacterial strains due to gamma radiation, heavy metals or food preservatives

    International Nuclear Information System (INIS)

    Mattar, Z.A.; Bashandy, A.S.

    2006-01-01

    The susceptibility of bacterial strains (B. cereus, Staph. aureus, Escherichia coli and Salmonella) against 10 different antibiotics that are commonly used against food borne pathogens was studied. All the tested strains were observed to tolerate up to 100 mg/l copper sulphate or lead acetate, and there was a positive correlations between the tolerance to high levels of Cu or Pb and multiple antibiotic resistance was investigated. When the food preservatives (potassium sorbate or sodium benzoate) were added to the growth medium at different concentrations, the bacterial strains were able to tolerate up to 1000 ppm potassium sorbate or sodium benzoate (MIC). The antibiotic resistance of these strains was increased when grown on media supplemented with the MIC of sodium sorbate or potassium benzoate. When these bacterial strains were irradiated at dose levels of 1 or 3 or 5 KGy and examined for antibiotic sensitivity, a correlation was observed between the increases of radiation dose up to 5 KGy and the antibiotic resistance in all the studied strains

  7. Biotransformation of tetracycline by a novel bacterial strain Stenotrophomonas maltophilia DT1.

    Science.gov (United States)

    Leng, Yifei; Bao, Jianguo; Chang, Gaofeng; Zheng, Han; Li, Xingxing; Du, Jiangkun; Snow, Daniel; Li, Xu

    2016-11-15

    Although several abiotic processes have been reported that can transform antibiotics, little is known about whether and how microbiological processes may degrade antibiotics in the environment. This work isolated one tetracycline degrading bacterial strain, Stenotrophomonas maltophilia strain DT1, and characterized the biotransformation of tetracycline by DT1 under various environmental conditions. The biotransformation rate was the highest when the initial pH was 9 and the reaction temperature was at 30°C, and can be described using the Michaelis-Menten model under different initial tetracycline concentrations. When additional substrate was present, the substrate that caused increased biomass resulted in a decreased biotransformation rate of tetracycline. According to disk diffusion tests, the biotransformation products of tetracycline had lower antibiotic potency than the parent compound. Six possible biotransformation products were identified, and a potential biotransformation pathway was proposed that included sequential removal of N-methyl, carbonyl, and amine function groups. Results from this study can lead to better estimation of the fate and transport of antibiotics in the environment and has the potential to be utilized in designing engineering processes to remove tetracycline from water and soil. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Factors influencing production of lipase under metal supplementation by bacterial strain, Bacillus subtilis BDG-8.

    Science.gov (United States)

    Dhevahi, B; Gurusamy, R

    2014-11-01

    Lipases are biocatalyst having wide applications in industries due to their versatile properties. In the present study, a lipolytic bacterial strain, Bacillus subtilis BDG-8 was isolated from an oil based industrial soil. The effect of selenium and nickel as a media supplement on enhancement of lipase production, was studied individually with the isolated strain by varying the concentration of selected metal. 60 μg l(-1) selenium enhanced lipase production to an enzyme activity measuring 7.8 U ml(-1) while 40 μgI(-1) nickel gave the maximum enzyme activity equivalent to 7.5 U ml(-1). However, nickel and selenium together at a range of concentration with an equal w/v ratio, at 60 μg l(-1) each, showed the maximum lipase activity of 8.5 U ml(-1). The effect of pH and temperature on lipase production showed maximum enzyme activity in the presence of each of the metals at pH 7 and 35°C among the other tested ranges. After optimisation of the parameters such as metal concentration, pH and temperature lipase production by Bacillus subtilis BDG-8 had increased several folds. This preliminary investigation may consequently lead as to various industrial applications such as treatment of wastewater contaminated with metal or oil with simultaneous lipase production.

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

    Science.gov (United States)

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

    2015-03-01

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

  10. ‘Olegusella massiliensis’ strain KHD7, a new bacterial genus isolated from the female genital tract

    Directory of Open Access Journals (Sweden)

    K. Diop

    2016-07-01

    Full Text Available We report the main characteristics of ‘Olegusella massiliensis’ gen. nov., sp. nov., strain KHD7 (= CSUR P2268=DSM 101849, a new member of the Coriobacteriaceae family isolated from the vaginal flora of a patient with bacterial vaginosis.

  11. Soil microbial species loss affects plant biomass and survival of an introduced bacterial strain, but not inducible plant defences

    NARCIS (Netherlands)

    Kurm, Viola; van der Putten, W.H.; Pineda, A.M.; Hol, W.H.G.

    2018-01-01

    • Background and Aims Plant growth-promoting rhizobacteria (PGPR) strains can influence plant–insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence

  12. Soil microbial species loss affects plant biomass and survival of an introduced bacterial strain, but not inducible plant defences

    NARCIS (Netherlands)

    Kurm, Viola; Putten, Van Der Wim H.; Pineda, Ana; Hol, G.W.H.

    2018-01-01

    • Background and Aims: Plant growth-promoting rhizobacteria (PGPR) strains can influence plant-insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence

  13. Luminescence nanothermometry

    Science.gov (United States)

    Jaque, Daniel; Vetrone, Fiorenzo

    2012-07-01

    The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed.The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed. This work was supported by the Universidad Autónoma de Madrid and Comunidad Autónoma de Madrid (Project S2009/MAT-1756), by the Spanish Ministerio de Educacion y Ciencia (MAT2010-16161) and by Caja Madrid Foundation.

  14. Transport of EDTA into cells of the EDTA-degrading bacterial strain DSM 9103.

    Science.gov (United States)

    Witschel, M; Egli, T; Zehnder, A J; Wehrli, E; Spycher, M

    1999-04-01

    In the bacterial strain DSM 9103, which is able to grow with the complexing agent EDTA as the sole source of carbon, nitrogen and energy, the transport of EDTA into whole cells was investigated. EDTA uptake was found to be dependent on speciation: free EDTA and metal-EDTA complexes with low stability constants were readily taken up, whereas those with stability constants higher than 1016 were not transported. In EDTA-grown cells, initial transport rates of CaEDTA showed substrate-saturation kinetics with a high apparent affinity for CaEDTA (affinity constant Kt= 0.39 microM). Several uncouplers had an inhibitory effect on CaEDTA transport. CaEDTA uptake was also significantly reduced in the presence of an inhibitor of ATPase and the ionophore nigericin, which dissipates the proton gradient. Valinomycin, however, which affects the electrical potential, had little effect on uptake, indicating that EDTA transport is probably driven by the proton gradient. Of various structurally related compounds tested only Ca2+-complexed diethylenetriaminepentaacetate (CaDTPA) competitively inhibited CaEDTA transport. Uptake in fumarate-grown cells was low compared to that measured in EDTA-grown bacteria. These results strongly suggest that the first step in EDTA degradation by strain DSM 9103 consists of transport by an inducible energy-dependent carrier. Uptake experiments with 45Ca2+ in the presence and absence of EDTA indicated that Ca2+ is transported together with EDTA into the cells. In addition, these transport studies and electron-dispersive X-ray analysis of electron-dense intracellular bodies present in EDTA-grown cells suggest that two mechanisms acting simultaneously allow the cells to cope with the large amounts of metal ions taken up together with EDTA. In one mechanism the metal ions are excreted, in the other they are inactivated intracellularly in polyphosphate granules.

  15. Resistance and Inactivation Kinetics of Bacterial Strains Isolated from the Non-Chlorinated and Chlorinated Effluents of a WWTP

    Directory of Open Access Journals (Sweden)

    Claudia Coronel-Olivares

    2013-08-01

    Full Text Available The microbiological quality of water from a wastewater treatment plant that uses sodium hypochlorite as a disinfectant was assessed. Mesophilic aerobic bacteria were not removed efficiently. This fact allowed for the isolation of several bacterial strains from the effluents. Molecular identification indicated that the strains were related to Aeromonas hydrophila, Escherichia coli (three strains, Enterobacter cloacae, Kluyvera cryocrescens (three strains, Kluyvera intermedia, Citrobacter freundii (two strains, Bacillus sp. and Enterobacter sp. The first five strains, which were isolated from the non-chlorinated effluent, were used to test resistance to chlorine disinfection using three sets of variables: disinfectant concentration (8, 20 and 30 mg·L−1, contact time (0, 15 and 30 min and water temperature (20, 25 and 30 °C. The results demonstrated that the strains have independent responses to experimental conditions and that the most efficient treatment was an 8 mg·L−1 dose of disinfectant at a temperature of 20 °C for 30 min. The other eight strains, which were isolated from the chlorinated effluent, were used to analyze inactivation kinetics using the disinfectant at a dose of 15 mg·L−1 with various retention times (0, 10, 20, 30, 60 and 90 min. The results indicated that during the inactivation process, there was no relationship between removal percentage and retention time and that the strains have no common response to the treatments.

  16. Plant domestication and the assembly of bacterial and fungal communities associated with strains of the common sunflower, Helianthus annuus.

    Science.gov (United States)

    Leff, Jonathan W; Lynch, Ryan C; Kane, Nolan C; Fierer, Noah

    2017-04-01

    Root and rhizosphere microbial communities can affect plant health, but it remains undetermined how plant domestication may influence these bacterial and fungal communities. We grew 33 sunflower (Helianthus annuus) strains (n = 5) that varied in their extent of domestication and assessed rhizosphere and root endosphere bacterial and fungal communities. We also assessed fungal communities in the sunflower seeds to investigate the degree to which root and rhizosphere communities were influenced by vertical transmission of the microbiome through seeds. Neither root nor rhizosphere bacterial communities were affected by the extent of sunflower domestication, but domestication did affect the composition of rhizosphere fungal communities. In particular, more modern sunflower strains had lower relative abundances of putative fungal pathogens. Seed-associated fungal communities strongly differed across strains, but several lines of evidence suggest that there is minimal vertical transmission of fungi from seeds to the adult plants. Our results indicate that plant-associated fungal communities are more strongly influenced by host genetic factors and plant breeding than bacterial communities, a finding that could influence strategies for optimizing microbial communities to improve crop yields. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  17. Proanthocyanidins-Will they effectively restrain conspicuous bacterial strains devolving on urinary tract infection?

    Science.gov (United States)

    Jagannathan, Venkataseshan; Viswanathan, Pragasam

    2018-05-18

    Struvite or infection stones are one of the major clinical burdens among urinary tract infection, which occur due to the interaction between microbes and urine mineral components. Numerous urinary tract infection (UTI) causing microbes regulate through biofilm formation for survival from host defense, it is often found difficult in its eradication with simple anti-microbial agents and also the chance of recurrence and resistance development is significantly high. Cranberry consumption and maintenance of urinary tract health have been supported by clinical, epidemiological, and mechanistic studies. It predominantly contains proanthocyanidins that belong to the class of polyphenols with repeating catechin and epicatechin monomeric units. Numerous studies have correlated proanthocyanidin consumption and prevention of bacterial adhesion to uroepithelial cells. Quorum sensing (QS) is the prime mechanism that drives bacteria to coordinate biofilm development and virulence expression. Reports have shown that proanthocyanidins are effective in disrupting cell-cell communication by quenching signal molecules. Overall, this review assesses the merits of proanthocyanidins and its effective oppression on adherence, motility, QS, and biofilm formation of major UTI strains such as Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis by comparing and evaluating results from many significant findings. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Biodegradation of hexavalent chromium (Cr+6) in wastewater using Pseudomonas sp. and Bacillus sp. bacterial strains

    Energy Technology Data Exchange (ETDEWEB)

    Qasim, Muhammad [Department of Chemical Engineering, American University of Sharjah (United Arab Emirates)

    2013-07-01

    The recovery of toxic metal compounds is a deep concern in all industries. Hexavalent chromium is particularly worrying because of its toxic influence on human health. In this paper, biodegradation of hexavalent chromium (Cr+6) present in wastewater has been studied using two different bacterial strains; Pseudomonas sp. and Bacillus sp. A chemostat (with and without recycle of cells) with 10 L liquid culture volume was used to study the substrate and the biomass cell concentrations with time. Also, the degree of substrate conversion was studied by the varying the dilution rate as an independent parameter. The dilution rate (ratio of feed flow rate to the culture volume) was varied by varying the feed volumetric rate from 110-170 mL/h for inlet hexavalent chromium concentrations of 70 mg/dm3. The results show that a chemostat with recycle gives a better performance in terms of substrate conversion than a chemostat without a recycle. Moreover, the degree of substrate conversion decreases as the dilution rate is increased. Also, Bacillus sp. was found to give higher conversions compared to pseudomonas sp.

  19. Application of two bacterial strains for wastewater bioremediation and assessment of phenolics biodegradation.

    Science.gov (United States)

    Paisio, Cintia E; Quevedo, María R; Talano, Melina A; González, Paola S; Agostini, Elizabeth

    2014-08-01

    The use of native bacteria is a useful strategy to decontaminate industrial effluents. In this work, two bacterial strains isolated from polluted environments constitutes a promising alternative since they were able to remove several phenolic compounds not only from synthetic solutions but also from effluents derived from a chemical industry and a tannery which are complex matrices. Acinetobacter sp. RTE 1.4 showed ability to completely remove 2-methoxyphenol (1000 mg/L) while Rhodococcus sp. CS 1 not only degrade the same concentration of this compound but also removed 4- chlorophenol, 2,4-dichlorophenol and pentachlorophenol with high efficiency. Moreover, both bacteria degraded phenols naturally present or even exogenously added at high concentrations in effluents from the chemical industry and a tannery in short time (up to 5 d). In addition, a significant reduction of biological oxygen demand and chemical oxygen demand values was achieved after 7 d of treatment for both effluents using Acinetobacter sp. RTE 1.4 and Rhodococcus sp. CS1, respectively. These results showed that Acinetobacter sp. RTE1.4 and Rhodococcus sp. CS 1 might be considered as useful biotechnological tools for an efficient treatment of different effluents, since they showed wide versatility to detoxify these complex matrices, even supplemented with high phenol concentrations.

  20. Characterization of CRISPR-Cas system in clinical Staphylococcus epidermidis strains revealed its potential association with bacterial infection sites

    DEFF Research Database (Denmark)

    Li, Qiuchun; Xie, Xiaolei; Yin, Kequan

    2016-01-01

    Staphylococcus epidermidis is considered as a major cause of nosocomial infections, bringing an immense burden to healthcare systems. Virulent phages have been confirmed to be efficient in combating the pathogen, but the prensence of CRISPR-Cas system, which is a bacterial immune system eliminating...... phages was reported in few S. epidermidis strains. In this study, the CRISPR-Cas system was detected in 12 from almost 300 published genomes in GenBank and by PCR of cas6 gene in 18 strains out of 130 clinical isolates obtained in Copenhagen. Four strains isolated in 1965-1966 harboured CRISPR elements...... spacers located in the CRISPR1 locus with homolgy to virulent phage 6ec DNA sequences, and 19 strains each carrying 2 or 3 different spacers recognizing this phage, implied that the CRISPR-Cas immunity could be abrogated by nucleotide mismatch between the spacer and its target phage sequence, while new...

  1. Strains of bacterial species induce a greatly varied acute adaptive immune response: The contribution of the accessory genome.

    Directory of Open Access Journals (Sweden)

    Uri Sela

    2018-01-01

    Full Text Available A fundamental question in human susceptibility to bacterial infections is to what extent variability is a function of differences in the pathogen species or in individual humans. To focus on the pathogen species, we compared in the same individual the human adaptive T and B cell immune response to multiple strains of two major human pathogens, Staphylococcus aureus and Streptococcus pyogenes. We found wide variability in the acute adaptive immune response induced by various strains of a species, with a unique combination of activation within the two arms of the adaptive response. Further, this was also accompanied by a dramatic difference in the intensity of the specific protective T helper (Th response. Importantly, the same immune response differences induced by the individual strains were maintained across multiple healthy human donors. A comparison of isogenic phage KO strains, demonstrated that of the pangenome, prophages were the major contributor to inter-strain immune heterogeneity, as the T cell response to the remaining "core genome" was noticeably blunted. Therefore, these findings extend and modify the notion of an adaptive response to a pathogenic bacterium, by implying that the adaptive immune response signature of a bacterial species should be defined either per strain or alternatively to the species' 'core genome', common to all of its strains. Further, our results demonstrate that the acquired immune response variation is as wide among different strains within a single pathogenic species as it is among different humans, and therefore may explain in part the clinical heterogeneity observed in patients infected with the same species.

  2. Bacterial Feeders, the Nematode Caenorhabditis elegans and the Flagellate Cercomonas longicauda, have different Effects on Outcome of Competition among the Pseudomonas Biocontrol Strains CHA0 and DSS73

    DEFF Research Database (Denmark)

    Pedersen, Annette; Nybroe, Ole; Winding, Anne

    2009-01-01

    How bacterial feeding fauna affects colonization and survival of bacteria in soil is not well understood, which constrains the applicability of bacterial inoculants in agriculture. This study aimed to unravel how food quality of bacteria and bacterial feeders with different feeding habits (the......50090 or one of two biocontrol strains P. fluorescens CHA0 or Pseudomonas sp. DSS73) or combinations of two bacterial strains. DSM50090 is a suitable food bacterium, DSS73 is of intermediate food quality, and CHA0 is inedible to the bacterial feeders. Bacterial and protozoan cell numbers were measured...... predation pressure. Hence, the results suggested that the outcome of competition among bacteria depended on their ability to cope with the prevailing bacterial predator....

  3. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2009-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

  4. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2008-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs

  5. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2012-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materials in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

  6. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2009-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs

  7. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2013-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materials in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

  8. The strains recommended for use in the bacterial reverse mutation test (OECD guideline 471) can be certified as non-genetically modified organisms.

    Science.gov (United States)

    Sugiyama, Kei-Ichi; Yamada, Masami; Awogi, Takumi; Hakura, Atsushi

    2016-01-01

    The bacterial reverse mutation test, commonly called Ames test, is used worldwide. In Japan, the genetically modified organisms (GMOs) are regulated under the Cartagena Domestic Law, and organisms obtained by self-cloning and/or natural occurrence would be exempted from the law case by case. The strains of Salmonella typhimurium and Escherichia coli recommended for use in the bacterial reverse mutation test (OECD guideline 471), have been considered as non-GMOs because they can be constructed by self-cloning or naturally occurring bacterial strains, or do not disturb the biological diversity. The present article explains the reasons why these tester strains should be classified as non-GMOs.

  9. Evaluation of insecticidal activity of a bacterial strain, Serratia sp. EML-SE1 against diamondback moth.

    Science.gov (United States)

    Jeong, Hyung Uk; Mun, Hye Yeon; Oh, Hyung Keun; Kim, Seung Bum; Yang, Kwang Yeol; Kim, Iksoo; Lee, Hyang Burm

    2010-08-01

    To identify novel bioinsecticidal agents, a bacterial strain, Serratia sp. EML-SE1, was isolated from a dead larva of the lepidopteran diamondback moth (Plutella xylostella) collected from a cabbage field in Korea. In this study, the insecticidal activity of liquid cultures in Luria-Bertani broth (LBB) and nutrient broth (NB) of a bacterial strain, Serratia sp. EML-SE1 against thirty 3rd and 4th instar larvae of the diamondback moth was investigated on a Chinese cabbage leaf housed in a round plastic cage (Ø 10 x 6 cm). 72 h after spraying the cabbage leaf with LBB and NB cultures containing the bacterial strain, the mortalities of the larvae were determined to be 91.7% and 88.3%, respectively. In addition, the insecticidal activity on potted cabbage containing 14 leaves in a growth cage (165 x 83 x 124 cm) was found to be similar to that of the plastic cage experiment. The results of this study provided valuable information on the insecticidal activity of the liquid culture of a Serratia species against the diamondback moth.

  10. Conformational locking by design: relating strain energy with luminescence and stability in rigid metal-organic frameworks.

    Science.gov (United States)

    Shustova, Natalia B; Cozzolino, Anthony F; Dincă, Mircea

    2012-12-05

    Minimization of the torsional barrier for phenyl ring flipping in a metal-organic framework (MOF) based on the new ethynyl-extended octacarboxylate ligand H(8)TDPEPE leads to a fluorescent material with a near-dark state. Immobilization of the ligand in the rigid structure also unexpectedly causes significant strain. We used DFT calculations to estimate the ligand strain energies in our and all other topologically related materials and correlated these with empirical structural descriptors to derive general rules for trapping molecules in high-energy conformations within MOFs. These studies portend possible applications of MOFs for studying fundamental concepts related to conformational locking and its effects on molecular reactivity and chromophore photophysics.

  11. Construction of a stable GFP-tagged Vibrio harveyi strain for bacterial dynamics analysis of abalone infection.

    Science.gov (United States)

    Travers, Marie-Agnès; Barbou, Annaïck; Le Goïc, Nelly; Huchette, Sylvain; Paillard, Christine; Koken, Marcel

    2008-12-01

    Vibrio harveyi is a bacterial marine pathogen that can cause fatal disease in a large range of vertebrates and invertebrates, including the commercially important marine gastropod, Haliotis tuberculata. Since 1997, strains of this bacterium have regularly been causing high mortalities in farmed and wild abalone populations. The way in which the pathogen enters into abalone and the disease transmission mechanisms are thus far unknown. Therefore, a pathogenic strain, ORM4, was green fluorescent protein-tagged and validated both for its growth characteristics and for its virulence as a genuine model for abalone disease. The strain allows V. harveyi quantification by flow cytometry in seawater and in abalone haemolymph as well as the in situ detection of the parasite inside abalone tissues.

  12. The inoculation method affects colonization and performance of bacterial inoculant strains in the phytoremediation of soil contaminated with diesel oil.

    Science.gov (United States)

    Afzal, Muhammad; Yousaf, Sohail; Reichenauer, Thomas G; Sessitsch, Angela

    2012-01-01

    Plants in combination with microorganisms can remediate soils, which are contaminated with organic pollutants such as petroleum hydrocarbons. Inoculation of plants with degrading bacteria is one approach to improve remediation processes, but is often not successful due to the competition with resident microorganisms. It is therefore of high importance to address the persistence and colonization behavior of inoculant strains. The objective of this study was to determine whether the inoculation method (seed imbibement and soil inoculation) influences bacterial colonization, plant growth promotion and hydrocarbon degradation. Italian ryegrass was grown in non-sterilized soil polluted with diesel and inoculated with different alkane-degrading strains Pantoea sp. ITSI10, Pantoea sp. BTRH79 and Pseudomonas sp. MixRI75 individually as well as in combination. Inoculation generally had a beneficial effect on plant biomass production and hydrocarbon degradation, however, strains inoculated in soil performed better than applied by seed imbibement. Performance correlated with the colonization efficiency of the inoculated strains. The highest hydrocarbon degradation was observed in the treatment, in which all three strains were inoculated in combination into soil. Our study revealed that besides the degradation potential and competitive ability of inoculant strains the inoculation method plays an important role in determining the success of microbial inoculation.

  13. Antibiotic Resistance and Virulence Phenotypes of Recent Bacterial Strains Isolated from Urinary Tract Infections in Elderly Patients with Prostatic Disease

    Directory of Open Access Journals (Sweden)

    Cristina Delcaru

    2017-05-01

    Full Text Available Acute bacterial prostatitis is one of the frequent complications of urinary tract infection (UTI. From the approximately 10% of men having prostatitis, 7% experience a bacterial prostatitis. The purpose of this study was to investigate the prevalence of uropathogens associated with UTIs in older patients with benign prostatic hyperplasia and to assess their susceptibility to commonly prescribed antibiotics as well as the relationships between microbial virulence and resistance features. Uropathogenic Escherichia coli was found to be the most frequent bacterial strain isolated from patients with benign prostatic hyperplasia, followed by Enterococcus spp., Enterobacter spp., Klebsiella spp., Proteus spp., Pseudomonas aeruginosa, and Serratia marcescens. Increased resistance rates to tetracyclines, quinolones, and sulfonamides were registered. Besides their resistance profiles, the uropathogenic isolates produced various virulence factors with possible implications in the pathogenesis process. The great majority of the uropathogenic isolates revealed a high capacity to adhere to HEp-2 cell monolayer in vitro, mostly exhibiting a localized adherence pattern. Differences in the repertoire of soluble virulence factors that can affect bacterial growth and persistence within the urinary tract were detected. The Gram-negative strains produced pore-forming toxins—such as hemolysins, lecithinases, and lipases—proteases, siderophore-like molecules resulted from the esculin hydrolysis and amylases, while Enterococcus sp. strains were positive only for caseinase and esculin hydrolase. Our study demonstrates that necessity of investigating the etiology and local resistance patterns of uropathogenic organisms, which is crucial for determining appropriate empirical antibiotic treatment in elderly patients with UTI, while establishing correlations between resistance and virulence profiles could provide valuable input about the clinical evolution and

  14. Cooked meat products made of coarsely ground pork: the main bacterial strains of bacterial flora, their heat resistance and effect on spoilage

    Directory of Open Access Journals (Sweden)

    Esko Petäjä

    1993-09-01

    Full Text Available This study was conducted to investigate the bacterial flora of the surface layer and the core of meat products made of coarsely ground pork at the moment of spoilage when stored at 7°C or 4°C. The dominating strains were isolated, their heat resistance was studied in APT-broth, on APT-agar and in coarsely ground cured pork, and their growth after heating and effect on spoilage were followed in coarsely ground cured pork. The first signs of spoilage appeared in the surface layer of the products. The strains were coccoid lactic acid bacteria with counts ranging from 3,5 to 7.8 log cfu (colony forming units/g. They survived only accidentally after heating for 15 minutes at 72°C in APT-broth. The core of the products contained only coccoid lactic acid bacteria or only pseudomonads or both as the main bacterial strains. The counts ranged from 2.6 to 6.0 log cfu/g. Most of the strains isolated from the core survived after heating for 30 minutes at 72°C in APT-broth in at least three tests out of six. The most noticeable result of the study was the occurence of heat-resistant pseudomonads in the core. It must be pointed out that all pseudomonads found survived after heating for 60 minutes at 72°C in APT-broth, and often after heating for 15 minutes at 72°C in coarsely ground cured pork (core 72°C. The cfu number of the two most heat-resistant streptococcus strains decreased only 1 log unit over 15 minutes at 72°C in coarsely ground cured pork. The numbers of inoculated pseudomonads decreased but those of streptococci rose by a maximum of 1 log unit when the experimental porks were kept at 4°C after heating. This indicates that streptococci and pseudomonads probably do not constitute a serious spoilage factor in cooked meat products, but spoilage is generally effected by bacteria which have contaminated the surface layer of the products after heat treatment.

  15. New Parameters to Quantitatively Express the Invasiveness of Bacterial Strains from Implant-Related Orthopaedic Infections into Osteoblast Cells

    Directory of Open Access Journals (Sweden)

    Davide Campoccia

    2018-04-01

    Full Text Available Complete eradication of bacterial infections is often a challenging task, especially in presence of prosthetic devices. Invasion of non-phagocytic host cells appears to be a critical mechanism of microbial persistence in host tissues. Hidden within host cells, bacteria elude host defences and antibiotic treatments that are intracellularly inactive. The intracellular invasiveness of bacteria is generally measured by conventional gentamicin protection assays. The efficiency of invasion, however, markedly differs across bacterial species and adjustments to the titre of the microbial inocula used in the assays are often needed to enumerate intracellular bacteria. Such changes affect the standardisation of the method and hamper a direct comparison of bacteria on a same scale. This study aims at investigating the precise relation between inoculum, in terms of multiplicity of infection (MOI, and internalised bacteria. The investigation included nine Staphylococcus aureus, seven Staphylococcus epidermidis, five Staphylococcus lugdunensis and two Enterococcus faecalis clinical strains, which are co-cultured with MG63 human osteoblasts. Unprecedented insights are offered on the relations existing between MOI, number of internalised bacteria and per cent of internalised bacteria. New parameters are identified that are of potential use for qualifying the efficiency of internalization and compare the behaviour of bacterial strains.

  16. New Parameters to Quantitatively Express the Invasiveness of Bacterial Strains from Implant-Related Orthopaedic Infections into Osteoblast Cells.

    Science.gov (United States)

    Campoccia, Davide; Montanaro, Lucio; Ravaioli, Stefano; Cangini, Ilaria; Testoni, Francesca; Visai, Livia; Arciola, Carla Renata

    2018-04-03

    Complete eradication of bacterial infections is often a challenging task, especially in presence of prosthetic devices. Invasion of non-phagocytic host cells appears to be a critical mechanism of microbial persistence in host tissues. Hidden within host cells, bacteria elude host defences and antibiotic treatments that are intracellularly inactive. The intracellular invasiveness of bacteria is generally measured by conventional gentamicin protection assays. The efficiency of invasion, however, markedly differs across bacterial species and adjustments to the titre of the microbial inocula used in the assays are often needed to enumerate intracellular bacteria. Such changes affect the standardisation of the method and hamper a direct comparison of bacteria on a same scale. This study aims at investigating the precise relation between inoculum, in terms of multiplicity of infection (MOI), and internalised bacteria. The investigation included nine Staphylococcus aureus , seven Staphylococcus epidermidis , five Staphylococcus lugdunensis and two Enterococcus faecalis clinical strains, which are co-cultured with MG63 human osteoblasts. Unprecedented insights are offered on the relations existing between MOI, number of internalised bacteria and per cent of internalised bacteria. New parameters are identified that are of potential use for qualifying the efficiency of internalization and compare the behaviour of bacterial strains.

  17. MALDI-TOF-MS with PLS Modeling Enables Strain Typing of the Bacterial Plant Pathogen Xanthomonas axonopodis

    Science.gov (United States)

    Sindt, Nathan M.; Robison, Faith; Brick, Mark A.; Schwartz, Howard F.; Heuberger, Adam L.; Prenni, Jessica E.

    2018-02-01

    Matrix-assisted desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) is a fast and effective tool for microbial species identification. However, current approaches are limited to species-level identification even when genetic differences are known. Here, we present a novel workflow that applies the statistical method of partial least squares discriminant analysis (PLS-DA) to MALDI-TOF-MS protein fingerprint data of Xanthomonas axonopodis, an important bacterial plant pathogen of fruit and vegetable crops. Mass spectra of 32 X. axonopodis strains were used to create a mass spectral library and PLS-DA was employed to model the closely related strains. A robust workflow was designed to optimize the PLS-DA model by assessing the model performance over a range of signal-to-noise ratios (s/n) and mass filter (MF) thresholds. The optimized parameters were observed to be s/n = 3 and MF = 0.7. The model correctly classified 83% of spectra withheld from the model as a test set. A new decision rule was developed, termed the rolled-up Maximum Decision Rule (ruMDR), and this method improved identification rates to 92%. These results demonstrate that MALDI-TOF-MS protein fingerprints of bacterial isolates can be utilized to enable identification at the strain level. Furthermore, the open-source framework of this workflow allows for broad implementation across various instrument platforms as well as integration with alternative modeling and classification algorithms.

  18. Isolation of non-sulphur photosynthetic bacterial strains efficient in hydrogen production at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.P.; Srivastava, S.C. (Banaras Hindu Univ., Varanasi (IN). Centre of Advanced Study in Botany)

    1991-01-01

    Four strains of non-sulphur photosynthetic bacteria were isolated from root zone associations of aquatic plants like Azolla, Salvinia and Eichhornia, as well as the deep-water rice. Based on the gross cell morphology and pigmentation, the isolates resembled Rhodopseudomonas sp. and have been designated as BHU strains 1 to 4, respectively. When subjected to elevated temperature (from 33-45{sup o}C), substantial growth/hydrogen production could be observed only in strains 1 and 4. Strains 2 and 3 on the other hand, showed diminished growth and negligible hydrogen photoproduction. The BHU strains 1 and 4 have been selected as the most active (thermostable) hydrogen producing strains of local origin as far as the Indian tropical climate is concerned. (author).

  19. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain

    Science.gov (United States)

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Micklem, Chris N.; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S.; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

    2016-01-01

    Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae. Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology. PMID:27247386

  20. Evaluation of biofilm formation by bacterial strains isolated from milking equipment and milk samples from cows with mastitis

    Directory of Open Access Journals (Sweden)

    Laura Gonçalves da Silva Chagas

    2017-08-01

    Full Text Available The presence of biofilm-forming bacteria from the mammary gland of dairy cows adhered to equipment in the milking environment represents one of the major causes of bacterial resistance during mastitis treatment. The aim of this study was to identify strains of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli in milk samples from cows with mastitis, as well as in the expansion tank and milking set liners. We aimed to quantify the extracellular proteins and polysaccharides in the biofilm produced by each strain. A total of 294 samples were collected from a dairy farm in the municipality of Uberlândia, Minas Gerais. To identify the S. aureus, S. epidermidis and E. coli isolates responsible for biofilm production, we tested the phenotype using the Congo red agar (CRA and microplate adhesion tests. Protein quantification was performed with a Bicinchoninic Acid Protein Assay Kit (BCA kit, and polysaccharides were quantified by the phenol sulfuric acid method. We identified eight strains of S. aureus, one strain of S. epidermidis and 11 strains of E. coli responsible for biofilm production, all of which showed a higher concentration of polysaccharides than proteins in the matrix. Escherichia coli was considered the most prevalent bacterium among the samples, and S. aureus was determined to be the largest biofilm producer. The results of the CRA and microplate adhesion tests were similar in regard to identification of the biofilm-producing strains according to their phenotype and matrix composition. The classification of S. aureus strains as major biofilm producers is of great concern for producers, as such bacteria are considered one of the predominant contagious etiological agents that cause bovine mastitis. In addition, our observation that E. coli and S. epidermidis can produce biofilms highlights the need to reassess prophylactic measures to avoid the adhesion of biofilm-producing bacteria.

  1. Strain Dependent Genetic Networks for Antibiotic-Sensitivity in a Bacterial Pathogen with a Large Pan-Genome.

    Directory of Open Access Journals (Sweden)

    Tim van Opijnen

    2016-09-01

    Full Text Available The interaction between an antibiotic and bacterium is not merely restricted to the drug and its direct target, rather antibiotic induced stress seems to resonate through the bacterium, creating selective pressures that drive the emergence of adaptive mutations not only in the direct target, but in genes involved in many different fundamental processes as well. Surprisingly, it has been shown that adaptive mutations do not necessarily have the same effect in all species, indicating that the genetic background influences how phenotypes are manifested. However, to what extent the genetic background affects the manner in which a bacterium experiences antibiotic stress, and how this stress is processed is unclear. Here we employ the genome-wide tool Tn-Seq to construct daptomycin-sensitivity profiles for two strains of the bacterial pathogen Streptococcus pneumoniae. Remarkably, over half of the genes that are important for dealing with antibiotic-induced stress in one strain are dispensable in another. By confirming over 100 genotype-phenotype relationships, probing potassium-loss, employing genetic interaction mapping as well as temporal gene-expression experiments we reveal genome-wide conditionally important/essential genes, we discover roles for genes with unknown function, and uncover parts of the antibiotic's mode-of-action. Moreover, by mapping the underlying genomic network for two query genes we encounter little conservation in network connectivity between strains as well as profound differences in regulatory relationships. Our approach uniquely enables genome-wide fitness comparisons across strains, facilitating the discovery that antibiotic responses are complex events that can vary widely between strains, which suggests that in some cases the emergence of resistance could be strain specific and at least for species with a large pan-genome less predictable.

  2. Comparison of some indigenous bacterial strains of pseudomonas ssp. for production of biosurfactants

    International Nuclear Information System (INIS)

    Sahafeeq, M.; Kokub, D.; Khalid, Z.M.; Malik, K.A.

    1991-01-01

    Some indigenous pseudomonas spp. were found to have the ability of emulsification, lowering the surface and interfacial tensions, and formation of high reciprocal CMCs. Six strains of Pseudomonas spp were compared for biosurfactant production grown on hexadecane. Supernatant from whole culture broth of these strains could lower surface tension from 65 mN/m to 28-32 nM/m, interfacial tension from 40 nM/m to 1-3 mN/m and had high reciprocal CMCs. When compared for emulsification ability by the culture broth of these strains, the emulsification index (E24) was found to range between 60-65. Biosurfactant containing culture broth of some strains could retain the property up to 80 C, pH of 13 and sodium chloride concentration for 17% which indicates their possible role in some depleted oil well. (author)

  3. SERS-based detection methods for screening of genetically modified bacterial strains

    DEFF Research Database (Denmark)

    Morelli, Lidia

    factories vary largely, including industrial production of valuable compounds for biofuels, polymer synthesis and food, cosmetic and pharmaceutical industry. The improvement of computational and biochemical tools has revolutionized the synthesis of novel modified microbial strains, opening up new......The importance of metabolic engineering has been growing over the last decades, establishing the use of genetically modified microbial strains for overproduction of metabolites at industrial scale as an innovative, convenient and biosustainable method. Nowadays, application areas of microbial...

  4. Biodegradation and detoxification of melanoidin from distillery effluent using an aerobic bacterial strain SAG{sub 5} of Alcaligenes faecalis

    Energy Technology Data Exchange (ETDEWEB)

    Santal, Anita Rani, E-mail: anita.gangotra@gmail.com [Department of Microbiology, Maharshi Dayanand University, Rohtak-124001, Haryana (India); Singh, N.P. [Centre for Biotechnology, Maharshi Dayanand University, Rohtak-124001, Haryana (India); Saharan, Baljeet Singh [Department of Microbiology, Kurukshetra University, Kurukshetra-136119, Haryana (India)

    2011-10-15

    Highlights: {yields} The Alcaligenes faecalis strain SAG{sub 5} decolorizes 72.6 {+-} 0.56% of melanoidins. {yields} The decolorization was achieved at pH 7.5 and temperature 37 {sup o}C on 5th day. {yields} The distillery effluent after biological treatment is environmentally safe. - Abstract: Distillery effluent retains very dark brown color even after anaerobic treatment due to presence of various water soluble, recalcitrant and coloring compounds mainly melanoidins. In laboratory conditions, melanoidin decolorizing bacteria was isolated and optimized the cultural conditions at various incubation temperatures, pH, carbon sources, nitrogen sources and combined effect of both carbon and nitrogen sources. The optimum decolorization (72.6 {+-} 0.56%) of melanoidins was achieved at pH 7.5 and temperature 37 {sup o}C on 5th day of cultivation. The toxicity evaluation with mung bean (Vigna radiata) revealed that the raw distillery effluent was environmentally highly toxic as compared to biologically treated distillery effluent, which indicated that the effluent after bacterial treatment is environmentally safe. This proves to be novel biological treatment technique for biodegradation and detoxification of melanoidin from distillery effluent using the bacterial strain SAG{sub 5}.

  5. Production of putrescine-capped stable silver nanoparticle: its characterization and antibacterial activity against multidrug-resistant bacterial strains

    Science.gov (United States)

    Saha, Saswati; Gupta, Bhaskar; Gupta, Kamala; Chaudhuri, Mahua Ghosh

    2016-11-01

    Integration of biology with nanotechnology is now becoming attention-grabbing area of research. The antimicrobial potency of silver has been eminent from antiquity. Due to the recent desire for the enhancement of antibacterial efficacy of silver, various synthesis methods of silver in their nano dimensions are being practiced using a range of capping material. The present work highlights a facile biomimetic approach for production of silver nanoparticle being capped and stabilized by putrescine, possessing a diameter of 10-25 ± 1.5 nm. The synthesized nanoparticles have been analyzed spectrally and analytically. Morphological studies are carried out by high-resolution transmission electron microscopy and crystallinity by selected area electron diffraction patterns. Moreover, the elemental composition of the capped nanoparticles was confirmed by energy-dispersive X-ray spectroscopy analysis. A comparative study (zone of inhibition and minimum inhibitory concentration) regarding the interactions and antibacterial potentiality of the capped silver nanoparticles with respect to the bare ones reveal the efficiency of the capped one over the bare one. The bacterial kinetic study was executed to monitor the interference of nanoparticles with bacterial growth rate. The results also highlight the efficacy of putrescine-capped silver nanoparticles as effective growth inhibitors against multi-drug resistant human pathogenic bacterial strains, which may, thus, potentially be applicable as an effective antibacterial control system to fight diseases.

  6. Identification of electrode respiring, hydrocarbonoclastic bacterial strain Stenotrophomonas maltophilia MK2 highlights the untapped potential for environmental bioremediation

    Directory of Open Access Journals (Sweden)

    Krishnaveni Venkidusamy

    2016-12-01

    Full Text Available Electrode respiring bacteria (ERB possess a great potential for many biotechnological applications such as microbial electrochemical remediation systems (MERS because of their exoelectrogenic capabilities to degrade xenobiotic pollutants. Very few ERB have been isolated from MERS, those exhibited a bioremediation potential towards organic contaminants. Here we report once such bacterial strain, Stenotrophomonas maltophilia MK2, a facultative anaerobic bacterium isolated from a hydrocarbon fed MERS, showed a potent hydrocarbonoclastic behavior under aerobic and anaerobic environments. Distinct properties of the strain MK2 were anaerobic fermentation of the amino acids, electrode respiration, anaerobic nitrate reduction and the ability to metabolize n-alkane components (C8-C36 of petroleum hydrocarbons including the biomarkers, pristine and phytane. The characteristic of diazoic dye decolorization was used as a criterion for pre-screening the possible electrochemically active microbial candidates. Bioelectricity generation with concomitant dye decolorization in MERS showed that the strain is electrochemically active. In acetate fed microbial fuel cells, maximum current density of 273±8 mA/m2 (1000Ω was produced (power density 113±7 mW/m2 by strain MK2 with a coulombic efficiency of 34.8 %. Further, the presence of possible alkane hydroxylase genes (alkB and rubA in the strain MK2 indicated that the genes involved in hydrocarbon degradation are of diverse origin. Such observations demonstrated the potential of facultative hydrocarbon degradation in contaminated environments. Identification of such a novel petrochemical hydrocarbon degrading ERB is likely to offer a new route to the sustainable bioremedial process of source zone contamination with simultaneous energy generation through MERS.

  7. Biodegradation of oil spill by petroleum refineries using consortia of novel bacterial strains.

    Science.gov (United States)

    Singh, Bina; Bhattacharya, Amit; Channashettar, Veeranna A; Jeyaseelan, C Paul; Gupta, Sachin; Sarma, Priyangshu M; Mandal, Ajoy K; Lal, Banwari

    2012-08-01

    Feasibility study carried out at the site prior to the full scale study showed that the introduced bacterial consortium effectively adapted to the local environment of the soil at bioremediation site. The soil samples were collected from the contaminated fields after treatment with bacterial consortium at different time intervals and analyzed by gas chromatography after extraction with hexane and toluene. At time zero (just before initiation of bioremediation), the concentration of total petroleum hydrocarbons in the soil (25-cm horizon) of plot A, B, C and D was 30.90 %, 18.80 %, 25.90 % and 29.90 % respectively, after 360 days of treatment with microbial consortia was reduced to 0.97 %, 1.0 %, 1.0 %, and 1.1 % respectively. Whereas, only 5 % degradation was observed in the control plot after 365 days (microbial consortium not applied).

  8. Bacterial succession during curing process of a skate (Dipturus batis) and isolation of novel strains.

    Science.gov (United States)

    Reynisson, E; Thornór Marteinsson, V; Jónsdóttir, R; Magnússon, S H; Hreggvidsson, G O

    2012-08-01

    To study the succession of cultivated and uncultivated microbes during the traditional curing process of skate. The microbial diversity was evaluated by sequencing 16Sr RNA clone libraries and cultivation in variety of media from skate samples taken periodically during a 9-day curing process. A pH shift was observed (pH 6·64-9·27) with increasing trimethylamine (2·6 up to 75·6 mg N per 100 g) and total volatile nitrogen (TVN) (from 58·5 to 705·8 mg N per 100 g) but with relatively slow bacterial growth. Uncured skate was dominated by Oceanisphaera and Pseudoalteromonas genera but was substituted after curing by Photobacterium and Aliivibrio in the flesh and Pseudomonas on the skin. Almost 50% of the clone library is derived from putative undiscovered species. Cultivation and enrichment strategies resulted in isolation of putatively new species belonging to the genera Idiomarina, Rheinheimera, Oceanisphaera, Providencia and Pseudomonas. The most abundant genera able to hydrolyse urea to ammonia were Oceanisphaera, Psychrobacter, Pseudoalteromonas and isolates within the Pseudomonas genus. The curing process of skate is controlled and achieved by a dynamic bacterial community where the key players belong to Oceanisphaera, Pseudoalteromonas, Photobacterium, Aliivibrio and Pseudomonas. For the first time, the bacterial population developments in the curing process of skate are presented and demonstrate a reservoir of many yet undiscovered bacterial species. No Claim to Norwegian Government works Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  9. Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels.

    Science.gov (United States)

    Guan, Xuefang; Xu, Qingxian; Zheng, Yi; Qian, Lei; Lin, Bin

    To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940) and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v) in simulated gastric juice (pH 2.5) for 2h and in simulated intestinal fluid (pH 8.0) for 3h. The auto-aggregation rate increased to 87.74% after 24h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  10. Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels

    Directory of Open Access Journals (Sweden)

    Xuefang Guan

    Full Text Available ABSTRACT Objective To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. Methods The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. Results The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940 and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v in simulated gastric juice (pH 2.5 for 2 h and in simulated intestinal fluid (pH 8.0 for 3 h. The auto-aggregation rate increased to 87.74% after 24 h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. Conclusion These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health.

  11. luminescence properties

    Indian Academy of Sciences (India)

    1Faculty of Science and Arts, Department of Chemistry, Bozok University, Yozgat 66900, Turkey. 2Faculty of Science, Department of Chemistry, Erciyes ... synthesized by the conventional solid-state reaction method, their crystal structures and luminescence properties were investigated. X-ray diffraction patterns (XRD) ...

  12. Biodegradation of phenol and benzene by endophytic bacterial strains isolated from refinery wastewater-fed Cannabis sativa.

    Science.gov (United States)

    Iqbal, Aneela; Arshad, Muhammad; Hashmi, Imran; Karthikeyan, Raghupathy; Gentry, Terry J; Schwab, Arthur Paul

    2017-06-13

    The presence of benzene and phenol in the environment can lead to serious health effects in humans and warrant development of efficient cleanup strategies. The aim of the present work was to assess the potential of indigenous endophytic bacterial strains to degrade benzene and phenol. Seven strains were successfully isolated from Cannabis sativa plants irrigated with oil refinery wastewater. Molecular characterization was performed by 16S rRNA gene sequencing. Phenol was biodegraded almost completely with Achromobacter sp. (AIEB-7), Pseudomonas sp. (AIEB-4), and Alcaligenes sp. (AIEB-6) at 250, 500, and 750 mg L -1 ; however, the degradation was only 81%, 72%, and 69%, respectively, when exposed to 1000 mg L -1 . Bacillus sp. (AIEB-1), Enterobacter sp. (AIEB-3), and Acinetobacter sp. (AIEB-2) degraded benzene significantly at 250, 500, and 750 mg L -1 . However, these strains showed 80%, 72%, and 68% benzene removal at 1000 mg L -1 exposure, respectively. Rates of degradation could be modeled with first-order kinetics with rate constant values of 1.86 × 10 -2 for Pseudomonas sp. (AIEB-4) and 1.80 × 10 -2  h -1 for Bacillus sp. (AIEB-1) and half-lives of 1.5 and 1.6 days, respectively. These results establish a foundation for further testing of the phytoremediation of hydrocarbon-contaminated soils in the presence of these endophytic bacteria.

  13. The Genomic Sequence of the Oral Pathobiont Strain NI1060 Reveals Unique Strategies for Bacterial Competition and Pathogenicity.

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    Youssef Darzi

    Full Text Available Strain NI1060 is an oral bacterium responsible for periodontitis in a murine ligature-induced disease model. To better understand its pathogenicity, we have determined the complete sequence of its 2,553,982 bp genome. Although closely related to Pasteurella pneumotropica, a pneumonia-associated rodent commensal based on its 16S rRNA, the NI1060 genomic content suggests that they are different species thriving on different energy sources via alternative metabolic pathways. Genomic and phylogenetic analyses showed that strain NI1060 is distinct from the genera currently described in the family Pasteurellaceae, and is likely to represent a novel species. In addition, we found putative virulence genes involved in lipooligosaccharide synthesis, adhesins and bacteriotoxic proteins. These genes are potentially important for host adaption and for the induction of dysbiosis through bacterial competition and pathogenicity. Importantly, strain NI1060 strongly stimulates Nod1, an innate immune receptor, but is defective in two peptidoglycan recycling genes due to a frameshift mutation. The in-depth analysis of its genome thus provides critical insights for the development of NI1060 as a prime model system for infectious disease.

  14. Antimicrobial activity of Lactobacillus strains of chicken origin against bacterial pathogenss.

    Science.gov (United States)

    Dec, Marta; Puchalski, Andrzej; Nowaczek, Anna; Wernicki, Andrzej

    2016-03-01

    This study was conducted to identify and evaluate the antimicrobial activity of some Lactobacillus isolates of chicken origin. Among 90 isolates 14 Lactobacillus species were distinguished using MALDI-TOF mass spectrometry and 16S-ARDRA. The dominant species was L. salivarius (34.4%), followed by L. johnsonii (23.3%), L. crispatus (13.3%) and L. reuteri (11.1%). All lactobacilli were screened for antimicrobial activity against wild-type strains of Salmonella enterica, Escherichia coli, and Clostridium perfringens. Results from the agar slab method showed that all Lactobacillus isolates were able to produce active compounds on solid media with antagonistic properties against these pathogens. The highest sensitivity to lactobacilli was observed in C. perfringens strains, and the lowest in E. coli. Lactobacillus salivarius exhibited particularly strong antagonism towards all of the indicator bacteria. Strains of L. ingluviei and L. johnsonii and one strain of L. salivarius (10d) selectively inhibited the growth of C. perfringens. No antimicrobial activity of many Lactobacillus isolates was observed when cell-free culture supernatant was used in a well diffusion assay. All Lactobacillus isolates exhibited the ability to produce H2O2 and proved to be hydrophobic (excluding one of L. salivarius). [Int Microbiol 19(1):57-67 (2016)]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  15. [Processes of plant colonization by Methylobacterium strains and some bacterial properties ].

    Science.gov (United States)

    Romanovskaia, V A; Stoliar, S M; Malashenko, Iu R; Dodatko, T N

    2001-01-01

    The pink-pigmented facultative methylotrophic bacteria (PPFMB) of the genus Methylobacterium are indespensible inhabitants of the plant phyllosphere. Using maize Zea mays as a model, the ways of plant colonization by PPFMB and some properties of the latter that might be beneficial to plants were studied. A marked strain, Methylobacterium mesophilicum APR-8 (pULB113), was generated to facilitate the detection of the methylotrophic bacteria inoculated into the soil or applied to the maize leaves. Colonization of maize leaves by M. mesophilicum APR-8 (pULB113) occurred only after the bacteria were applied onto the leaf surface. In this case, the number of PPFMB cells on inoculated leaves increased with plant growth. During seed germination, no colonization of maize leaves with M. mesophilicum cells occurred immediately from the soil inoculated with the marked strain. Thus, under natural conditions, colonization of plant leaves with PPFMB seems to occur via soil particle transfer to the leaves by air. PPFMB monocultures were not antagonistic to phytopathogenic bacteria. However, mixed cultures of epiphytic bacteria containing Methylobacterium mesophilicum or M. extorquens did exhibit an antagonistic effect against the phytopathogenic bacteria studied (Xanthomonas camprestris, Pseudomonas syringae, Erwinia carotovora, Clavibacter michiganense, and Agrobacterium tumifaciens). Neither epiphytic and soil strains of Methylobacterium extorquens, M. organophillum, M. mesophilicum, and M. fujisawaense catalyzed ice nucleation. Hence, they cause no frost injury to plants. Thus, the results indicate that the strains of the genus Methylobacterium can protect plants against adverse environmental factors.

  16. Mutagenic and antimutagenic activities of Artemisia absinthium volatile oil by the bacterial reverse mutation assay in Salmonella typhimurium strains TA98 and TA100

    Directory of Open Access Journals (Sweden)

    Mahboubeh Taherkhani

    2014-09-01

    Full Text Available Objective: To investigate the mutagenic and antimutagenic activities of Artemisia absinthium L. (A. absinthium essential oil by the bacterial reverse mutation assay in Salmonella typhimurium (S. typhimurium strains. Methods: Water-distilled essential oil of A. absinthium collected from Ardabil, NorthWestern Iran, was investigated for mutagenic and antimutagenic activities. In present study, the mutagenic and antimutagenic activities of A. absinthium oil were investigated by the bacterial revere mutation assay in S. typhimurium TA98 and TA100 strains with and without S9 (microsomal mutagenesis assay. Results: The comparative mutagenicity effect was seen in 1.5 mg/plate by the bacterial reverse mutation assay in S. typhimurium TA98 strains, without S9 and the excellent antimutagenicity effect was seen in 1.5 mg/plate against S. typhimurium TA100, without S9. Conclusions: The mutagenicity and antimutagenicity effects of the volatile oil of A. absinthium were seen without the presence of metabolic activation.

  17. Evolution of Bacterial Global Modulators: Role of a Novel H-NS Paralogue in the Enteroaggregative Escherichia coli Strain 042.

    Science.gov (United States)

    Prieto, A; Bernabeu, M; Aznar, S; Ruiz-Cruz, S; Bravo, A; Queiroz, M H; Juárez, A

    2018-01-01

    Bacterial genomes sometimes contain genes that code for homologues of global regulators, the function of which is unclear. In members of the family Enterobacteriaceae , cells express the global regulator H-NS and its paralogue StpA. In Escherichia coli , out of providing a molecular backup for H-NS, the role of StpA is poorly characterized. The enteroaggregative E. coli strain 042 carries, in addition to the hns and stpA genes, a third gene encoding an hns paralogue ( hns2 ). We present in this paper information about its biological function. Transcriptomic analysis has shown that the H-NS2 protein targets a subset of the genes targeted by H-NS. Genes targeted by H-NS2 correspond mainly with horizontally transferred (HGT) genes and are also targeted by the Hha protein, a fine-tuner of H-NS activity. Compared with H-NS, H-NS2 expression levels are lower. In addition, H-NS2 expression exhibits specific features: it is sensitive to the growth temperature and to the nature of the culture medium. This novel H-NS paralogue is widespread within the Enterobacteriaceae . IMPORTANCE Global regulators such as H-NS play key relevant roles enabling bacterial cells to adapt to a changing environment. H-NS modulates both core and horizontally transferred (HGT) genes, but the mechanism by which H-NS can differentially regulate these genes remains to be elucidated. There are several instances of bacterial cells carrying genes that encode homologues of the global regulators. The question is what the roles of these proteins are. We noticed that the enteroaggregative E. coli strain 042 carries a new hitherto uncharacterized copy of the hns gene. We decided to investigate why this pathogenic E. coli strain requires an extra H-NS paralogue, termed H-NS2. In our work, we show that H-NS2 displays specific expression and regulatory properties. H-NS2 targets a subset of H-NS-specific genes and may help to differentially modulate core and HGT genes by the H-NS cellular pool.

  18. Colonization of Vitis vinifera by a Green Fluorescence Protein-Labeled, gfp-Marked Strain of Xylophilus ampelinus, the Causal Agent of Bacterial Necrosis of Grapevine

    OpenAIRE

    Grall, Sophie; Manceau, Charles

    2003-01-01

    The dynamics of Xylophilus ampelinus were studied in Vitis vinifera cv. Ugni blanc using gfp-marked bacterial strains to evaluate the relative importance of epiphytic and endophytic phases of plant colonization in disease development. Currently, bacterial necrosis of grapevine is of economic importance in vineyards in three regions in France: the Cognac, Armagnac, and Die areas. This disease is responsible for progressive destruction of vine shoots, leading to their death. We constructed gfp-...

  19. Effectiveness of Origanum vulgare L. and Origanum majorana L. essential oils in inhibiting the growth of bacterial strains isolated from the patients with conjunctivitis

    OpenAIRE

    Oliveira, Jana Luíza Toscano Mendes de; Diniz, Margareth de Fátima Melo; Lima, Edeltrudes de Oliveira; Souza, Evandro Leite de; Trajano, Vinícius Nogueira; Santos, Bernadete Helena Cavalcante

    2009-01-01

    This study aimed to evaluate the antibacterial activity of Origanum vulgare L. and O. majorana L. essential oils on Staphylococcus aureus, S. coagulase negative, Enterobacter spp., Proteus spp., Acinetobacter spp., Klebsiella spp. isolated from the patients with conjunctivitis. The results showed a prominent inhibitory effect of both the essential oils on all the bacterial strains, noted by the large bacterial growth inhibition zones (15-32mm). The Minimum Inhibitory Concentrations (MIC) valu...

  20. Genomic survey of pathogenicity determinants and VNTR markers in the cassava bacterial pathogen Xanthomonas axonopodis pv. Manihotis strain CIO151.

    Science.gov (United States)

    Arrieta-Ortiz, Mario L; Rodríguez-R, Luis M; Pérez-Quintero, Álvaro L; Poulin, Lucie; Díaz, Ana C; Arias Rojas, Nathalia; Trujillo, Cesar; Restrepo Benavides, Mariana; Bart, Rebecca; Boch, Jens; Boureau, Tristan; Darrasse, Armelle; David, Perrine; Dugé de Bernonville, Thomas; Fontanilla, Paula; Gagnevin, Lionel; Guérin, Fabien; Jacques, Marie-Agnès; Lauber, Emmanuelle; Lefeuvre, Pierre; Medina, Cesar; Medina, Edgar; Montenegro, Nathaly; Muñoz Bodnar, Alejandra; Noël, Laurent D; Ortiz Quiñones, Juan F; Osorio, Daniela; Pardo, Carolina; Patil, Prabhu B; Poussier, Stéphane; Pruvost, Olivier; Robène-Soustrade, Isabelle; Ryan, Robert P; Tabima, Javier; Urrego Morales, Oscar G; Vernière, Christian; Carrere, Sébastien; Verdier, Valérie; Szurek, Boris; Restrepo, Silvia; López, Camilo; Koebnik, Ralf; Bernal, Adriana

    2013-01-01

    Xanthomonas axonopodis pv. manihotis (Xam) is the causal agent of bacterial blight of cassava, which is among the main components of human diet in Africa and South America. Current information about the molecular pathogenicity factors involved in the infection process of this organism is limited. Previous studies in other bacteria in this genus suggest that advanced draft genome sequences are valuable resources for molecular studies on their interaction with plants and could provide valuable tools for diagnostics and detection. Here we have generated the first manually annotated high-quality draft genome sequence of Xam strain CIO151. Its genomic structure is similar to that of other xanthomonads, especially Xanthomonas euvesicatoria and Xanthomonas citri pv. citri species. Several putative pathogenicity factors were identified, including type III effectors, cell wall-degrading enzymes and clusters encoding protein secretion systems. Specific characteristics in this genome include changes in the xanthomonadin cluster that could explain the lack of typical yellow color in all strains of this pathovar and the presence of 50 regions in the genome with atypical nucleotide composition. The genome sequence was used to predict and evaluate 22 variable number of tandem repeat (VNTR) loci that were subsequently demonstrated as polymorphic in representative Xam strains. Our results demonstrate that Xanthomonas axonopodis pv. manihotis strain CIO151 possesses ten clusters of pathogenicity factors conserved within the genus Xanthomonas. We report 126 genes that are potentially unique to Xam, as well as potential horizontal transfer events in the history of the genome. The relation of these regions with virulence and pathogenicity could explain several aspects of the biology of this pathogen, including its ability to colonize both vascular and non-vascular tissues of cassava plants. A set of 16 robust, polymorphic VNTR loci will be useful to develop a multi-locus VNTR analysis

  1. Quality and characteristics of fermented ginseng seed oil based on bacterial strain and extraction method

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    Myung-Hee Lee

    2017-07-01

    Results and Conclusion: The color of the fermented ginseng seed oil did not differ greatly according to the fermentation or extraction method. The highest phenolic compound content recovered with the use of supercritical fluid extraction combined with fermentation using the Bacillus subtilis Korea Food Research Institute (KFRI 1127 strain. The fatty acid composition did not differ greatly according to fermentation strain and extraction method. The phytosterol content of ginseng seed oil fermented with Bacillus subtilis KFRI 1127 and extracted using the supercritical fluid method was highest at 983.58 mg/100 g. Therefore, our results suggested that the ginseng seed oil fermented with Bacillus subtilis KFRI 1127 and extracted using the supercritical fluid method can yield a higher content of bioactive ingredients, such as phenolics, and phytosterols, without impacting the color or fatty acid composition of the product.

  2. High Frequency and Diversity of Antimicrobial Activities Produced by Nasal Staphylococcus Strains against Bacterial Competitors.

    Directory of Open Access Journals (Sweden)

    Daniela Janek

    2016-08-01

    Full Text Available The human nasal microbiota is highly variable and dynamic often enclosing major pathogens such as Staphylococcus aureus. The potential roles of bacteriocins or other mechanisms allowing certain bacterial clones to prevail in this nutrient-poor habitat have hardly been studied. Of 89 nasal Staphylococcus isolates, unexpectedly, the vast majority (84% was found to produce antimicrobial substances in particular under habitat-specific stress conditions, such as iron limitation or exposure to hydrogen peroxide. Activity spectra were generally narrow but highly variable with activities against certain nasal members of the Actinobacteria, Proteobacteria, Firmicutes, or several groups of bacteria. Staphylococcus species and many other Firmicutes were insusceptible to most of the compounds. A representative bacteriocin was identified as a nukacin-related peptide whose inactivation reduced the capacity of the producer Staphylococcus epidermidis IVK45 to limit growth of other nasal bacteria. Of note, the bacteriocin genes were found on mobile genetic elements exhibiting signs of extensive horizontal gene transfer and rearrangements. Thus, continuously evolving bacteriocins appear to govern bacterial competition in the human nose and specific bacteriocins may become important agents for eradication of notorious opportunistic pathogens from human microbiota.

  3. Construction of a full-length infectious bacterial artificial chromosome clone of duck enteritis virus vaccine strain

    Science.gov (United States)

    2013-01-01

    Background Duck enteritis virus (DEV) is the causative agent of duck viral enteritis, which causes an acute, contagious and lethal disease of many species of waterfowl within the order Anseriformes. In recent years, two laboratories have reported on the successful construction of DEV infectious clones in viral vectors to express exogenous genes. The clones obtained were either created with deletion of viral genes and based on highly virulent strains or were constructed using a traditional overlapping fosmid DNA system. Here, we report the construction of a full-length infectious clone of DEV vaccine strain that was cloned into a bacterial artificial chromosome (BAC). Methods A mini-F vector as a BAC that allows the maintenance of large circular DNA in E. coli was introduced into the intergenic region between UL15B and UL18 of a DEV vaccine strain by homologous recombination in chicken embryoblasts (CEFs). Then, the full-length DEV clone pDEV-vac was obtained by electroporating circular viral replication intermediates containing the mini-F sequence into E. coli DH10B and identified by enzyme digestion and sequencing. The infectivity of the pDEV-vac was validated by DEV reconstitution from CEFs transfected with pDEV-vac. The reconstructed virus without mini-F vector sequence was also rescued by co-transfecting the Cre recombinase expression plasmid pCAGGS-NLS/Cre and pDEV-vac into CEF cultures. Finally, the in vitro growth properties and immunoprotection capacity in ducks of the reconstructed viruses were also determined and compared with the parental virus. Results The full genome of the DEV vaccine strain was successfully cloned into the BAC, and this BAC clone was infectious. The in vitro growth properties of these reconstructions were very similar to parental DEV, and ducks immunized with these viruses acquired protection against virulent DEV challenge. Conclusions DEV vaccine virus was cloned as an infectious bacterial artificial chromosome maintaining full

  4. Synergistic and additive effect of oregano essential oil and biological silver nanoparticles against multidrug-resistant bacterial strains

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    Sara eScandorieiro

    2016-05-01

    Full Text Available Bacterial resistance to conventional antibiotics has become a clinical and public health problem, making therapeutic decisions more challenging. Plant compounds and nanodrugs have been proposed as potential antimicrobial alternatives. Studies have shown that oregano (Origanum vulgare essential oil (OEO and silver nanoparticles have potent antibacterial activity, also against multidrug-resistant strains; however, the strong organoleptic characteristics of OEO and the development of resistance to these metal nanoparticles can limit their use. This study evaluated the antibacterial effect of a two-drug combination of biologically synthesized silver nanoparticles (bio-AgNP, produced by Fusarium oxysporum, and OEO against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. OEO and bio-AgNP showed bactericidal effects against all seventeen strains tested, with minimal inhibitory concentrations (MIC ranging from 0.298 to 1.193 mg/mL and 62.5 to 250 µM, respectively. Time-kill curves indicated that OEO acted rapidly (within 10 min, while the metallic nanoparticles took 4 h to kill Gram-negative bacteria and 24 h to kill Gram-positive bacteria. The combination of the two compounds resulted in a synergistic or additive effect, reducing their MIC values and reducing the time of action compared to bio-AgNP used alone, i.e., 20 min for Gram-negative bacteria and 7 h for Gram-positive bacteria. Scanning electron microscopy (SEM revealed similar morphological alterations in Staphylococcus aureus (non-methicillin-resistant S. aureus, non-MRSA cells exposed to three different treatments (OEO, bio-AgNP and combination of the two, which appeared cell surface blebbing. Individual and combined treatments showed reduction in cell density and decrease in exopolysaccharide matrix compared to untreated bacterial cells. It indicated that this composition have an antimicrobial activity against S. aureus by disrupting cells. Both compounds

  5. Synergistic and Additive Effect of Oregano Essential Oil and Biological Silver Nanoparticles against Multidrug-Resistant Bacterial Strains.

    Science.gov (United States)

    Scandorieiro, Sara; de Camargo, Larissa C; Lancheros, Cesar A C; Yamada-Ogatta, Sueli F; Nakamura, Celso V; de Oliveira, Admilton G; Andrade, Célia G T J; Duran, Nelson; Nakazato, Gerson; Kobayashi, Renata K T

    2016-01-01

    Bacterial resistance to conventional antibiotics has become a clinical and public health problem, making therapeutic decisions more challenging. Plant compounds and nanodrugs have been proposed as potential antimicrobial alternatives. Studies have shown that oregano (Origanum vulgare) essential oil (OEO) and silver nanoparticles have potent antibacterial activity, also against multidrug-resistant strains; however, the strong organoleptic characteristics of OEO and the development of resistance to these metal nanoparticles can limit their use. This study evaluated the antibacterial effect of a two-drug combination of biologically synthesized silver nanoparticles (bio-AgNP), produced by Fusarium oxysporum, and OEO against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. OEO and bio-AgNP showed bactericidal effects against all 17 strains tested, with minimal inhibitory concentrations (MIC) ranging from 0.298 to 1.193 mg/mL and 62.5 to 250 μM, respectively. Time-kill curves indicated that OEO acted rapidly (within 10 min), while the metallic nanoparticles took 4 h to kill Gram-negative bacteria and 24 h to kill Gram-positive bacteria. The combination of the two compounds resulted in a synergistic or additive effect, reducing their MIC values and reducing the time of action compared to bio-AgNP used alone, i.e., 20 min for Gram-negative bacteria and 7 h for Gram-positive bacteria. Scanning electron microscopy (SEM) revealed similar morphological alterations in Staphylococcus aureus (non-methicillin-resistant S. aureus, non-MRSA) cells exposed to three different treatments (OEO, bio-AgNP and combination of the two), which appeared cell surface blebbing. Individual and combined treatments showed reduction in cell density and decrease in exopolysaccharide matrix compared to untreated bacterial cells. It indicated that this composition have an antimicrobial activity against S. aureus by disrupting cells. Both compounds showed very low

  6. An Endophytic Bacterial Strain Isolated from Eucommia ulmoides Inhibits Southern Corn Leaf Blight

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    Ting Ding

    2017-05-01

    Full Text Available Bacillus subtilis DZSY21 isolated from the leaves of Eucommia ulmoides oliv. was labeled by antibiotic marker and found to effectively colonize the leaves of maize plant. Agar diffusion assays and biocontrol effect experiments showed that strain DZSY21 and its lipopeptides had antagonistic activity against Bipolaris maydis, as well as high biocontrol effects on southern corn leaf blight caused by B. maydis. Using MALDI-TOF-MS analysis, we detected the presence of antimicrobial surfactin A, surfactin B, and fengycin in the strain DZSY21. Signaling pathways mediated by DZSY21 were analyzed by testing the expression of key plant genes involved in regulation of salicylic acid (SA or JA/ET pathways, the defense-related genes PR1 and LOX were concurrently expressed in the leaves of DZSY21-treated plants; this corresponded to slight increase in the expression level of PDF1.2 and decreases in ERF gene transcription levels. The results indicated an induced systemic response that is dependent on the SA and jasmonic acid (JA pathways. Thus, we hypothesized that the strain DZSY21 inhibits B. maydis by producing antifungal lipopeptides and activating an induced systemic response through SA- and JA-dependent signaling pathways. This work describes a mechanism behind reduced disease severity in plants inoculated with the endophytic bacteria DZSY21.

  7. [Isolation, identification and characterization of a diethylstilbestrol-degrading bacterial strain Serratia sp].

    Science.gov (United States)

    Xu, Ran-Fang; Sun, Min-Xia; Liu, Juan; Wang, Hong; Li, Xin; Zhu, Xue-Zhu; Ling, Wan-Ting

    2014-08-01

    Utilizing the diethylstilbestrol (DES)-degrading bacteria to biodegrade DES is a most reliable technique for cleanup of DES pollutants from the environment. However, little information is available heretofore on the isolation of DES-degrading bacteria and their DES removal performance in the environment. A novel bacterium capable of degrading DES was isolated from the activated sludge of a wastewater treatment plant. According to its morphology, physiochemical characteristics, and 16S rDNA sequence analysis, this strain was identified as Serratia sp.. The strain was an aerobic bacterium, and it could degrade 68.3% of DES (50 mg x L(-1)) after culturing for 7 days at 30 degrees C, 150 r x min(-1) in shaking flasks. The optimal conditions for DES biodegradation by the obtained strain were 30 degrees C, 40-60 mg x L(-1) DES, pH 7.0, 5% of inoculation volume, 0 g x L(-1) of added NaCl, and 10 mL of liquid medium volume in 100 mL flask.

  8. The longitudinal effect of a multi-strain probiotic on the intestinal bacterial microbiota of neonatal foals

    DEFF Research Database (Denmark)

    Schoster, Angelika; Guardabassi, Luca; Staempfli, H. R.

    2016-01-01

    REASONS FOR PERFORMING THE STUDY: The microbiota plays a key role in health and disease. Probiotics are a potential way to therapeutically modify the intestinal microbiota and prevent disease. OBJECTIVES: The aim of this study was to investigate the effects of probiotics on the bacterial microbiota...... of foals during and after administration. STUDY DESIGN: Randomised placebo controlled field trial. METHODS: Thirty-eight healthy neonatal foals enrolled in a prior study were selected. The foals had received a multi-strain probiotic (four Lactobacillus spp 3-4x10(3) cfu/g each, Bifidobacterium animalis spp...... or class level between treatment groups at any age (all p>0.08) but some significant changes in relative abundance of families. Probiotic administration did not result in an increased relative abundance of lactobacilli or bifidobacteria at any age (Lactobacillus: p = 0.95, p = 0.1 and p = 0...

  9. Extracellular polymeric substances (EPS) producing bacterial strains of municipal wastewater sludge: isolation, molecular identification, EPS characterization and performance for sludge settling and dewatering.

    Science.gov (United States)

    Bala Subramanian, S; Yan, S; Tyagi, R D; Surampalli, R Y

    2010-04-01

    Wastewater treatment plants often face the problems of sludge settling mainly due to sludge bulking. Generally, synthetic organic polymer and/or inorganic coagulants (ferric chloride, alum and quick lime) are used for sludge settling. These chemicals are very expensive and further pollute the environment. Whereas, the bioflocculants are environment friendly and may be used to flocculate the sludge. Extracellular polymeric substances (EPS) produced by sludge microorganisms play a definite role in sludge flocculation. In this study, 25 EPS producing strains were isolated from municipal wastewater treatment plant. Microorganisms were selected based on EPS production properties on solid agar medium. Three types of EPS (slime, capsular and bacterial broth mixture of both slime and capsular) were harvested and their characteristics were studied. EPS concentration (dry weight), viscosity and their charge (using a Zetaphoremeter) were also measured. Bioflocculability of obtained EPS was evaluated by measuring the kaolin clay flocculation activity. Six bacterial strains (BS2, BS8, BS9, BS11, BS15 and BS25) were selected based on the kaolin clay flocculation. The slime EPS was better for bioflocculation than capsular EPS and bacterial broth. Therefore, extracted slime EPS (partially purified) from six bacterial strains was studied in terms of sludge settling [sludge volume index (SVI)] and dewatering [capillary suction time (CST)]. Biopolymers produced by individual strains substantially improved dewaterability. The extracted slime EPS from six different strains were partially characterized. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  10. Antibacterial activity of the essential oil of Origanum vulgare L. (Lamiaceae against bacterial multiresistant strains isolated from nosocomial patients

    Directory of Open Access Journals (Sweden)

    Adalberto Coelho da Costa

    Full Text Available Antibiotics are considered the main therapeutic option to treat bacterial infections; however, there is the disadvantage of increasing bacterial resistance. Thus, the research of antimicrobials of plant origin has been an important alternative. This work aimed at determining the in vitro antibacterial activity of the essential oil of Origanum vulgare L. (Lamiaceae on multiresistant bacteria isolated from biological materials. 24 strains of nosocomial bacteria were used and divided into six different species that were inhibited by the essential oil in the preliminary "screening" which was accomplished by the diffusion technique in agar. MIC was determined by the microdilution method, beginning with solutions with the final concentrations: 8 up to 0.125% with the following results: The four samples (100% of Escherichia coli, Enterococcus faecalis and MRSA were inhibited by the essential oil at the concentration of 0.125%. Three samples (75% of Acinetobacter baumannii at 0.125% and a sample (25% at 0.5%; Klebsiella pneumoniae (75% at 0.125% and 25% at 0.25%; Pseudomonas aeruginosa (75% at 0.5% and 25% at 0.25%. MIC varied from 78 to 83%. It was concluded through the obtained data that there was not difference in the minimum bactericidal concentration (0.5% of the referred oil for Gram positive as well for Gram negative microorganisms.

  11. Plutonium interaction with a bacterial strain isolated from the waste isolation pilot plant (WIPP) environment

    International Nuclear Information System (INIS)

    Strietelmeier, B.A.; Kraus, S.M.; Leonard, P.A.; Triay, I.R.

    1996-01-01

    This work was conducted as part of a series of experiments to determine the association and interaction of various actinides with bacteria isolated from the WIPP site. The majority of bacteria that exist at the site are expected to be halophiles, or extreme halophiles, due to the high concentration of salt minerals at the location. Experiments were conducted to determine the toxicity of plutonium-n-239, neptunium-237 and americium-243 to several species of these halophiles and the results were reported elsewhere. As an extension of these experiments, we report an investigation of the type of association that occurs between 239 Pu and the isolate WIPP-1A, isolated by staff at Brookhaven National Laboratory, when grown in a high-salt, defined medium. Using scanning electron microscopy (SEM) techniques, we demonstrate a surface association of the 239 Pu with the bacterial cells

  12. Aerobic biodegradation of N-nitrosodimethylamine (NDMA) by axenic bacterial strains.

    Science.gov (United States)

    Sharp, Jonathan O; Wood, Thomas K; Alvarez-Cohen, Lisa

    2005-03-05

    The water contaminant N-nitrosodimethylamine (NDMA) is a probable human carcinogen whose appearance in the environment is related to the release of rocket fuel and to chlorine-based disinfection of water and wastewater. Although this compound has been shown to be biodegradable, there is minimal information about the organisms capable of this degradation, and little is understood of the mechanisms or biochemistry involved. This study shows that bacteria expressing monooxygenase enzymes functionally similar to those demonstrated to degrade NDMA in eukaryotes have the capability to degrade NDMA. Specifically, induction of the soluble methane monooxygenase (sMMO) expressed by Methylosinus trichosporium OB3b, the propane monooxygenase (PMO) enzyme of Mycobacterium vaccae JOB-5, and the toluene 4-monooxygenases found in Ralstonia pickettii PKO1 and Pseudomonas mendocina KR1 resulted in NDMA degradation by these strains. In each of these cases, brief exposure to acetylene gas, a suicide substrate for certain monooxygenases, inhibited the degradation of NDMA. Further, Escherichia coli TG1/pBS(Kan) containing recombinant plasmids derived from the toluene monooxygenases found in strains PKO1 and KR1 mimicked the behavior of the parent strains. In contrast, M. trichosporium OB3b expressing the particulate form of MMO, Burkholderia cepacia G4 expressing the toluene 2-monooxygenase, and Pseudomonas putida mt-2 expressing the toluene sidechain monooxygenase were not capable of NDMA degradation. In addition, bacteria expressing aromatic dioxygenases were not capable of NDMA degradation. Finally, Rhodococcus sp. RR1 exhibited the ability to degrade NDMA by an unidentified, constitutively expressed enzyme that, unlike the confirmed monooxygenases, was not inhibited by acetylene exposure. 2005 Wiley Periodicals, Inc.

  13. Enhanced biodegradation of alkane hydrocarbons and crude oil by mixed strains and bacterial community analysis.

    Science.gov (United States)

    Chen, Yu; Li, Chen; Zhou, Zhengxi; Wen, Jianping; You, Xueyi; Mao, Youzhi; Lu, Chunzhe; Huo, Guangxin; Jia, Xiaoqiang

    2014-04-01

    In this study, two strains, Acinetobacter sp. XM-02 and Pseudomonas sp. XM-01, were isolated from soil samples polluted by crude oil at Bohai offshore. The former one could degrade alkane hydrocarbons (crude oil and diesel, 1:4 (v/v)) and crude oil efficiently; the latter one failed to grow on alkane hydrocarbons but could produce rhamnolipid (a biosurfactant) with glycerol as sole carbon source. Compared with pure culture, mixed culture of the two strains showed higher capability in degrading alkane hydrocarbons and crude oil of which degradation rate were increased from 89.35 and 74.32 ± 4.09 to 97.41 and 87.29 ± 2.41 %, respectively. In the mixed culture, Acinetobacter sp. XM-02 grew fast with sufficient carbon source and produced intermediates which were subsequently utilized for the growth of Pseudomonas sp. XM-01 and then, rhamnolipid was produced by Pseudomonas sp. XM-01. Till the end of the process, Acinetobacter sp. XM-02 was inhibited by the rapid growth of Pseudomonas sp. XM-01. In addition, alkane hydrocarbon degradation rate of the mixed culture increased by 8.06 to 97.41 % compared with 87.29 % of the pure culture. The surface tension of medium dropping from 73.2 × 10(-3) to 28.6 × 10(-3) N/m. Based on newly found cooperation between the degrader and the coworking strain, rational investigations and optimal strategies to alkane hydrocarbons biodegradation were utilized for enhancing crude oil biodegradation.

  14. Antimicrobial and Anti-Swarming Effects of Bacteriocins and Biosurfactants from Probiotic Bacterial Strains against Proteus spp.

    Directory of Open Access Journals (Sweden)

    Laila Goudarzi

    2017-02-01

    Full Text Available Background:   Proteus spp. belongs to the family of Enterobacteriaceae. These bacteria are Gram-negative and motile microorganisms and known as the third most common causes of urinary tract infections. The aim of the current study was to investigate the effects of some secondary metabolites from probiotic strains of Lactobacillus spp. on swarming and growth of Proteus mirabilis and P. vulgaris. Methods:   After determination of optimal conditions for the growth and production of antimicrobials, bacteriocins and biosurfactants were partially purified from Lactobacillus culture supernatants. Then, effects of the purified compounds on growth and swarming migration of Proteus spp. were examined in the presence of various concentrations of semi-purified compounds. Results:  Results showed that the partially purified bacteriocins inhibited Proteus spp. swarming distance and had a significant reduction on the bacterial growth curves. Biosurfactants in a solvent form did not have any considerable effects on factors produced by Proteus spp. Conclusion:  According to the results, the secondary metabolites, especially bacteriocins or bacteriocin-like substances derived from Lactobacillus strains, can inhibit or reduce growth and swarming migration of Proteus spp. which are considered as the bacteria major virulence factors.

  15. Rhizospheric bacterial strain Brevibacterium casei MH8a colonizes plant tissues and enhances Cd, Zn, Cu phytoextraction by white mustard

    Directory of Open Access Journals (Sweden)

    Tomasz ePłociniczak

    2016-02-01

    Full Text Available Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants.The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%, Zn (86% and Cu (39% in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.

  16. Rhizospheric Bacterial Strain Brevibacterium casei MH8a Colonizes Plant Tissues and Enhances Cd, Zn, Cu Phytoextraction by White Mustard.

    Science.gov (United States)

    Płociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sułowicz, Sławomir; Piotrowska-Seget, Zofia

    2016-01-01

    Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.

  17. Endozoicomonas genomes reveal functional adaptation and plasticity in bacterial strains symbiotically associated with diverse marine hosts

    KAUST Repository

    Neave, Matthew J.

    2017-01-17

    Endozoicomonas bacteria are globally distributed and often abundantly associated with diverse marine hosts including reef-building corals, yet their function remains unknown. In this study we generated novel Endozoicomonas genomes from single cells and metagenomes obtained directly from the corals Stylophora pistillata, Pocillopora verrucosa, and Acropora humilis. We then compared these culture-independent genomes to existing genomes of bacterial isolates acquired from a sponge, sea slug, and coral to examine the functional landscape of this enigmatic genus. Sequencing and analysis of single cells and metagenomes resulted in four novel genomes with 60–76% and 81–90% genome completeness, respectively. These data also confirmed that Endozoicomonas genomes are large and are not streamlined for an obligate endosymbiotic lifestyle, implying that they have free-living stages. All genomes show an enrichment of genes associated with carbon sugar transport and utilization and protein secretion, potentially indicating that Endozoicomonas contribute to the cycling of carbohydrates and the provision of proteins to their respective hosts. Importantly, besides these commonalities, the genomes showed evidence for differential functional specificity and diversification, including genes for the production of amino acids. Given this metabolic diversity of Endozoicomonas we propose that different genotypes play disparate roles and have diversified in concert with their hosts.

  18. Endozoicomonas genomes reveal functional adaptation and plasticity in bacterial strains symbiotically associated with diverse marine hosts

    KAUST Repository

    Neave, Matthew J.; Michell, Craig; Apprill, Amy; Voolstra, Christian R.

    2017-01-01

    Endozoicomonas bacteria are globally distributed and often abundantly associated with diverse marine hosts including reef-building corals, yet their function remains unknown. In this study we generated novel Endozoicomonas genomes from single cells and metagenomes obtained directly from the corals Stylophora pistillata, Pocillopora verrucosa, and Acropora humilis. We then compared these culture-independent genomes to existing genomes of bacterial isolates acquired from a sponge, sea slug, and coral to examine the functional landscape of this enigmatic genus. Sequencing and analysis of single cells and metagenomes resulted in four novel genomes with 60–76% and 81–90% genome completeness, respectively. These data also confirmed that Endozoicomonas genomes are large and are not streamlined for an obligate endosymbiotic lifestyle, implying that they have free-living stages. All genomes show an enrichment of genes associated with carbon sugar transport and utilization and protein secretion, potentially indicating that Endozoicomonas contribute to the cycling of carbohydrates and the provision of proteins to their respective hosts. Importantly, besides these commonalities, the genomes showed evidence for differential functional specificity and diversification, including genes for the production of amino acids. Given this metabolic diversity of Endozoicomonas we propose that different genotypes play disparate roles and have diversified in concert with their hosts.

  19. Virulence of luminescent and non-luminescent isogenic vibrios towards gnotobiotic Artemia franciscana larvae and specific pathogen-free Litopenaeus vannamei shrimp.

    Science.gov (United States)

    Phuoc, L H; Defoirdt, T; Sorgeloos, P; Bossier, P

    2009-04-01

    This study was conducted to test the virulence of luminescent (L) and non-luminescent (NL) isogenic strains of Vibrio campbellii LMG21363, Vibrio harveyi BB120 (wild type) and quorum-sensing mutant strains derived from the wild type such as Vibrio harveyi BB152, BB170, MM30 and BB886. The NL strains could be obtained by culturing rifampicin-resistant luminescent strains in the dark under static condition. The virulence of the L and NL strains was tested in gnotobiotic Artemia franciscana larvae challenged with 10(4) CFU ml(-1) of bacteria. All luminescent isogenic tested strains showed higher virulence compared to the NL strains. The virulence of L and NL V. campbellii and V. harveyi BB120 was also tested in specific pathogen-free juvenile shrimp upon intramuscular injection with 10(6) CFU of bacteria. In contrast with Artemia, there was no significant difference in mortality between the groups challenged with L and NL strains (P > 0.05). The non-luminescent strains were not able to revert back to the luminescent state and quorum sensing did not influence this phenotypic shift. Luminescent Vibrio strains can switch to a non-luminescent state by culturing them in static conditions. The NL strains become less virulent as verified in Artemia. The luminescent state of Vibrio cells in a culture needs to be verified in order to assure maintenance of virulence.

  20. [Features of interaction bacterial strains Micrococcus luteus LBK1 from plants varieties/hybrids cucumber and sweet pepper and with fungus Fusarium oxysporum Scelecht].

    Science.gov (United States)

    Parfeniuk, A; Sterlikova, O; Beznosko, I; Krut', V

    2014-01-01

    The article presents the results of studying the impact of bacterial strain M. luteus LBK1, stimulating the growth and development of plant varieties/hybrids of cucumber and sweet pepper on the intensity of sporulation of the fungus F. oxysporum Scelecht--fusariose rot pathogen.

  1. Beneficial role of hydrophytes in removing Cr(VI) from wastewater in association with chromate-reducing bacterial strains Ochrobactrum intermedium and Brevibacterium.

    Science.gov (United States)

    Faisal, Muhammad; Hasnain, Shahida

    2005-01-01

    This study deals with the use of three chromium-resistant bacterial strains (Ochrobactrum intermedium CrT-1, Brevibacterium CrT-13, and CrM-1) in conjunction with Eichornia crassipes for the removal of toxic chromium from wastewater. Bacterial strains resulted in reduced uptake of chromate into inoculated plants as compared to noninoculated control plants. In the presence of different heavy metals, chromium uptake into the plants was 28.7 and 7.15% less at an initial K2CrO4 concentration of 100 and 500 microg ml(-1) in comparison to a metal free chromium solution. K2CrO4 uptake into the plant occurred at different pHs tested, but maximum uptake was observed at pH 5. Nevertheless, the bacterial strains caused some decrease in chromate uptake into the plants, but the combined effect of plants and bacterial strains conduce more removal of Cr(VI) from the solution.

  2. ‘Khoudiadiopia massiliensis’ gen. nov., sp. nov., strain Marseille-P2746TT, a new bacterial genus isolated from the female genital tract

    Directory of Open Access Journals (Sweden)

    A. Diop

    2017-09-01

    Full Text Available We report the main characteristics of ‘Khoudiadiopia massiliensis’ gen. nov., sp. nov., strain Marseille-P2746T (= CSUR P2746, a new member of the Peptoniphilaceae family isolated from a vaginal swab of a patient suffering from bacterial vaginosis.

  3. Voice Prosthetic Biofilm Formation and Candida Morphogenic Conversions in Absence and Presence of Different Bacterial Strains and Species on Silicone-Rubber

    NARCIS (Netherlands)

    van der Mei, Henny C.; Buijssen, Kevin J. D. A.; van der Laan, Bernard F. A. M.; Ovchinnikova, Ekatarina; Geertsema-Doornbusch, Gesinda I.; Atema-Smit, Jelly; van de Belt-Gritter, Betsy; Busscher, Henk J.

    2014-01-01

    Morphogenic conversion of Candida from a yeast to hyphal morphology plays a pivotal role in the pathogenicity of Candida species. Both Candida albicans and Candida tropicalis, in combination with a variety of different bacterial strains and species, appear in biofilms on silicone-rubber voice

  4. In vitro antibacterial activity of methanol and water extracts of adiantum capillus veneris and tagetes patula against multidrug resistant bacterial strains

    International Nuclear Information System (INIS)

    Hussain, M.M.; Ahmad, B.; Bashid, E.; Hashim, S.

    2014-01-01

    The aim of present study was to screen the antimicrobial activities of extracts of leaves and stems of Adiantum capillus veneris and Tagetes patula against multidrug-resistant (MDR) bacterial strains. Extracts from the leaves and stems of these plants were extracted with methanol and water and tested for their antibacterial activity by disc diffusion method against ten MDR bacterial strains i.e., Citrobacter freundii, Escherichia coli, Providencia, Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, Proteus vulgaris, Salmonella typhi, Shigella and Vibrio cholerae. Leaves methanol extract (LME) of Adiantum showed maximum Zone of Inhibition (ZI) against Providencia, Klebsiella pneumoniae, Shigella, Vibrio cholerae, Staphylococcus aureus, Proteus vulgaris and Salmonella typhi, whereas its stem methanol extract (SME) was very active against Escherichia coli, Klebsiella pneumoniae and Salmonella typhi. Similarly LME of Tagetes showed highest ZI against Escherichia coli and Vibrio cholerae while SME showed highest ZI to Escherichia coli, Vibrio cholerae, Providencia, Shigella and Klebsiella pneumoniae. Leaves water extract (LWE) of Adiantum was very active against all ten bacterial strains while its stem water extract (SWE) showed maximum ZI against Escherichia coli, Klebsiella pneumoniae and Salmonella typhi, Shigella, Proteus vulgaris and Providencia. LWE of Tagetes was only active against Vibrio cholerae whereas SWE was very active against Salmonella typhi and active against P. vulgaris, Citrobacter freundii and Vibrio cholerae. It was concluded from this study that extracts of both Adiantum and Tagetes have prominent activities against most of the MDR bacterial strains and needs further studies for utmost benefits. (author)

  5. Cytokine responses in primary chicken embryo intestinal cells infected with Campylobacter jejuni strains of human and chicken origin and the expression of bacterial virulence-associated genes

    DEFF Research Database (Denmark)

    Li, Yiping; Ingmer, Hanne; Madsen, Mogens

    2008-01-01

    of the bacterial genes. We have investigated the invasiveness of primary chicken embryo intestinal cells (CEICs) by C. jejuni strains of human and chicken origins and the production of pro-inflammatory cytokines as well as the expression of the bacterial virulence-associated genes during co-cultivation. Results C......-free media from another co-cultivation experiment also increased the expression of the virulence-associated genes in the C. jejuni chicken isolate, indicating that the expression of bacterial genes is regulated by component(s) secreted upon co-cultivation of bacteria and CEICs. Conclusion We show that under...... in vitro culture condition C. jejuni strains of both human and chicken origins can invade avian host cells with a pro-inflammatory response and that the virulence-associated genes of C. jejuni may play a role in this process....

  6. Bacterial Polymertropism, the Response to Strain-Induced Alignment of Polymers

    Science.gov (United States)

    Lemon, David J.

    In nature, bacteria often live in surface-associated communities known as biofilms. Biofilm-forming bacteria deposit a layer of polysaccharide on the surfaces they inhabit; hence, polysaccharide is their immediate environment on any surface. In this study, we examined how the physical characteristics of polysaccharide substrates influence the behavior of the biofilm-forming bacterium Myxococcus xanthus. M. xanthus colonies, and indeed those of the majority of biofilm-forming species tested, respond to the compression-induced deformation of polysaccharide substrates by preferentially spreading across the surface perpendicular to the axis of compression. This response is conserved across multiple distantly related phyla and is found in species with an array of distinct motility apparatuses.The birefringence and small angle X-ray scattering patterns of compressed polysaccharide substrates indicate that the directed surface movements of these bacteria consistently match the orientation of the long axes of aligned and tightly packed polysaccharide fibers in compressed substrates. Therefore, we refer to this behavior as polymertropism to denote that the directed movements are a response to the physical arrangement of the change in packing and alignment of the polymers in the substrate. In addition to altering the colony morphology we find the behavior of groups of cells, called flares, is also affected in several species resulting in increased flare speed, duration, and displacement on compressed gel substrates.We suggest that polymertropism, which requires a downward-facing motility apparatus in M. xanthus, may be responsible for the observed tendency of bacterial cells to follow trails of extruded and presumably aligned polysaccharides, which their neighbors secrete and deposit on the substrate as they move across it. Polymertropism may also play a role in the organization of bacteria in a biofilm, as the iterative process of polysaccharide trail deposition and

  7. Optimization of Culture Parameters for Maximum Polyhydroxybutyrate Production by Selected Bacterial Strains Isolated from Rhizospheric Soils.

    Science.gov (United States)

    Lathwal, Priyanka; Nehra, Kiran; Singh, Manpreet; Jamdagni, Pragati; Rana, Jogender S

    2015-01-01

    The enormous applications of conventional non-biodegradable plastics have led towards their increased usage and accumulation in the environment. This has become one of the major causes of global environmental concern in the present century. Polyhydroxybutyrate (PHB), a biodegradable plastic is known to have properties similar to conventional plastics, thus exhibiting a potential for replacing conventional non-degradable plastics. In the present study, a total of 303 different bacterial isolates were obtained from soil samples collected from the rhizospheric area of three crops, viz., wheat, mustard and sugarcane. All the isolates were screened for PHB (Poly-3-hydroxy butyric acid) production using Sudan Black staining method, and 194 isolates were found to be PHB positive. Based upon the amount of PHB produced, the isolates were divided into three categories: high, medium and low producers. Representative isolates from each category were selected for biochemical characterization; and for optimization of various culture parameters (carbon source, nitrogen source, C/N ratio, different pH, temperature and incubation time periods) for maximizing PHB accumulation. The highest PHB yield was obtained when the culture medium was supplemented with glucose as the carbon source, ammonium sulphate at a concentration of 1.0 g/l as the nitrogen source, and by maintaining the C/N ratio of the medium as 20:1. The physical growth parameters which supported maximum PHB accumulation included a pH of 7.0, and an incubation temperature of 30 degrees C for a period of 48 h. A few isolates exhibited high PHB accumulation under optimized conditions, thus showing a potential for their industrial exploitation.

  8. Luminescent screens

    International Nuclear Information System (INIS)

    Lu, C.-I.

    1982-01-01

    Luminescent screens which are useful for such purposes as intensifying screens for radiographs are comprised of a support bearing a layer of finely divided particles of a phosphor dispersed in a cross-linked polymeric matrix formed by heat-curing of a coating composition comprising an unsaturated cross-linkable polymer, a polymerizable acrylic monomer, a thermoplastic polyurethane elastomer, and a heat-activatable polymerization initiator. The phosphor layer includes voids formed by evaporation of an evaporable component which is present in the coating composition from which such layer is formed. (author)

  9. Biodegradation of Maya crude oil fractions by bacterial strains and a defined mixed culture isolated from Cyperus laxus rhizosphere soil in a contaminated site

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Ramirez, I. J.; Gutierrez-Rojas, M.; Favela-Torres, E. [Autonomous Metropolitan University (UAM)- Iztapalapa, Dept. of Biotechnology, Federal District (Mexico); Ramirez-Sada, H. [Autonomous Metropolitan University (UAM)-Xochimilco, Dept. of Biological Systems, Federal District (Mexico)

    2003-12-01

    Biodegradation of aliphatic, aromatic, and polar constituents of Maya crude oil by a set of isolated bacterial strains and a defined mixed culture made up with all isolated strains, was evaluated. The bacterial strains were obtained from the rhizosphere of Cyperus laxus, a native plant on a highly hydrocarbon-polluted site. Oxygen uptake rate was used to determine the culture transfer timing during the enrichment culture. Results showed that five of the isolated strains were able to degrade 50 per cent of the aliphatic fractions of Maya crude oil. With the defined mixed culture the level of biodegradation was 47 per cent for aliphatics and 6 per cent of the aromatic-polar mixture. When grown in the presence of total hydrocarbons, the defined mixed culture was able to degrade 40 per cent of the aliphatic fraction and 26 per cent of the aromatic fraction. By combining enrichment cultures with oxygen uptake rate to determine the culture transfer timing during the enrichment cultures allowed the isolation of bacterial strains that are able to degrade specific hydrocarbon fractions at high consumption rates. 28 refs., 4 tabs., 1 fig.

  10. Efficient biotransformation of herbicide diuron by bacterial strain Micrococcus sp. PS-1.

    Science.gov (United States)

    Sharma, Priyanka; Chopra, Adity; Cameotra, Swaranjit Singh; Suri, C Raman

    2010-11-01

    A Gram-positive, Micrococcus sp. strain PS-1 capable of utilizing phenylurea herbicide diuron as a sole carbon source at a high concentration (up to 250 ppm) was isolated from diuron storage site by selective enrichment study. The taxonomic characterization with 16S rRNA gene sequencing (1,477 bp) identified PS-1 as a member of Micrococcus sp. It was studied for the degradation of diuron and a range of its analogues (monuron, linuron, monolinuron, chlortoluron and fenuron). The shake flasks experiments demonstrated fast degradation of diuron (up to 96% at 250 ppm within 30 h incubation) with the addition of small quantity (0.01%) of non-ionic detergent. The relative degradation profile by the isolate was in the order of fenuron > monuron > diuron > linuron > monolinuron > chlortoluron. Further, the biochemical characterization of catabolic pathway by spectroscopic and chromatographic techniques demonstrated that the degradation proceeded via formation of dealkylated metabolites to form 3,4-dichloroaniline (3,4-DCA). It was the major metabolite formed, associated with profound increase in degradation kinetics in presence of appropriate additive.

  11. Hospitalized Premature Infants Are Colonized by Related Bacterial Strains with Distinct Proteomic Profiles

    Science.gov (United States)

    Xiong, Weili; Olm, Matthew R.; Thomas, Brian C.; Baker, Robyn; Firek, Brian; Morowitz, Michael J.; Hettich, Robert L.

    2018-01-01

    ABSTRACT During the first weeks of life, microbial colonization of the gut impacts human immune system maturation and other developmental processes. In premature infants, aberrant colonization has been implicated in the onset of necrotizing enterocolitis (NEC), a life-threatening intestinal disease. To study the premature infant gut colonization process, genome-resolved metagenomics was conducted on 343 fecal samples collected during the first 3 months of life from 35 premature infants housed in a neonatal intensive care unit, 14 of whom developed NEC, and metaproteomic measurements were made on 87 samples. Microbial community composition and proteomic profiles remained relatively stable on the time scale of a week, but the proteome was more variable. Although genetically similar organisms colonized many infants, most infants were colonized by distinct strains with metabolic profiles that could be distinguished using metaproteomics. Microbiome composition correlated with infant, antibiotics administration, and NEC diagnosis. Communities were found to cluster into seven primary types, and community type switched within infants, sometimes multiple times. Interestingly, some communities sampled from the same infant at subsequent time points clustered with those of other infants. In some cases, switches preceded onset of NEC; however, no species or community type could account for NEC across the majority of infants. In addition to a correlation of protein abundances with organism replication rates, we found that organism proteomes correlated with overall community composition. Thus, this genome-resolved proteomics study demonstrated that the contributions of individual organisms to microbiome development depend on microbial community context. PMID:29636439

  12. Hospitalized Premature Infants Are Colonized by Related Bacterial Strains with Distinct Proteomic Profiles

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    Christopher T. Brown

    2018-04-01

    Full Text Available During the first weeks of life, microbial colonization of the gut impacts human immune system maturation and other developmental processes. In premature infants, aberrant colonization has been implicated in the onset of necrotizing enterocolitis (NEC, a life-threatening intestinal disease. To study the premature infant gut colonization process, genome-resolved metagenomics was conducted on 343 fecal samples collected during the first 3 months of life from 35 premature infants housed in a neonatal intensive care unit, 14 of whom developed NEC, and metaproteomic measurements were made on 87 samples. Microbial community composition and proteomic profiles remained relatively stable on the time scale of a week, but the proteome was more variable. Although genetically similar organisms colonized many infants, most infants were colonized by distinct strains with metabolic profiles that could be distinguished using metaproteomics. Microbiome composition correlated with infant, antibiotics administration, and NEC diagnosis. Communities were found to cluster into seven primary types, and community type switched within infants, sometimes multiple times. Interestingly, some communities sampled from the same infant at subsequent time points clustered with those of other infants. In some cases, switches preceded onset of NEC; however, no species or community type could account for NEC across the majority of infants. In addition to a correlation of protein abundances with organism replication rates, we found that organism proteomes correlated with overall community composition. Thus, this genome-resolved proteomics study demonstrated that the contributions of individual organisms to microbiome development depend on microbial community context.

  13. Characterization of a novel oxyfluorfen-degrading bacterial strain Chryseobacterium aquifrigidense and its biochemical degradation pathway.

    Science.gov (United States)

    Zhao, Huanhuan; Xu, Jun; Dong, Fengshou; Liu, Xingang; Wu, Yanbing; Wu, Xiaohu; Zheng, Yongquan

    2016-08-01

    Persistent use of the diphenyl ether herbicides oxyfluorfen may seriously increase the health risks and ecological safety problems. A newly bacterium R-21 isolated from active soil was able to degrade and utilize oxyfluorfen as the sole carbon source. R-21 was identified as Chryseobacterium aquifrigidense by morphology, physiobiochemical characteristics, and genetic analysis. Under the optimum cultural conditions (pH 6.9, temperature 33.4 °C, and inoculum size 0.2 g L(-1)), R-21 could degrade 92.1 % of oxyfluorfen at 50 mg L(-1) within 5 days. During oxyfluorfen degradation, six metabolites were detected and identified by atmospheric pressure gas chromatography coupled to quadrupole-time of flight mass spectrometry and ultra-performance liquid chromatography coupled to quadrupole-time of flight mass spectrometry, and a plausible degradation pathway was deduced. Strain R-21 is a promising potential in bioremediation of oxyfluorfen-contaminated environments.

  14. Bio-transformation of selenium in Se-enriched bacterial strains of Lactobacillus casei.

    Science.gov (United States)

    Kurek, Eliza; Ruszczyńska, Anna; Wojciechowski, Marcin; Łuciuk, Anna; Michalska-Kacymirow, Magdalena; Motyl, Ilona; Bulska, Ewa

    Selenium is an element of very great importance for the proper functioning of the human body, mainly due to its antioxidant properties. Selenium exhibits a preventive effect in the case of cardiovascular disease, the immune system, male infertility and inhibits the toxic action of other agents. Selenium is important for Hashimoto's disease. Intake of selenium in the diet slows the aging process. The biological and toxicological effects of selenium strongly depend on its chemical form. Some organisms for example: plant, yeast, are capable of metabolizing low bioavailable selenium compounds (inorganic selenium) into its high bioavailable forms (organic selenium). The aim of this study was to investigate the bio-transformation of selenium by Lactobacillus bacteria towards the characterisation of selenium metabolites. The speciation of selenium was evaluated by high performance liquid chromatography with inductively coupled plasma mass spectrometry detector. The extraction of selenium species from lyophilized bacteria was executed with water, the mixture of lipase and protease, as well as lisozyme and sodium dodecyl sulphate. All investigated bacteria strains cultivated in the presence of Na2SeO3 effectively uptake selenium. Surprisingly, none of the applied extraction media exhibited a strong power to release the majority of the uptaken selenium compounds. Thus a maximum of 10% of the selenium was extracted from bacteria exposed to the enzymes. However, it was found that Lactobacillus bacteria are able to metabolize inorganic ions of selenium (IV) into Se-methionine, Se-methyloselenocysteine and other unidentified forms. The study confirmed the ability of probiotic bacteria to biotransform inorganic selenium into its organic derivatives. Therefore, Se-enriched bacteria can be considered as an addition to the functional food. selenium speciation, extraction procedure, Lactobacillus casei bacteria, Lactic acid bacteria (LAB), HPLC ICP-MS, functional food.

  15. Soil microbial species loss affects plant biomass and survival of an introduced bacterial strain, but not inducible plant defences.

    Science.gov (United States)

    Kurm, Viola; van der Putten, Wim H; Pineda, Ana; Hol, W H Gera

    2018-02-12

    Plant growth-promoting rhizobacteria (PGPR) strains can influence plant-insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence of rare soil microbe reduction on induced systemic resistance (ISR) in a wild ecotype of Arabidopsis thaliana against the aphid Myzus persicae was investigated. To create a gradient of microbial abundances, soil was inoculated with a serial dilution of a microbial community and responses of Arabidopsis plants that originated from the same site as the soil microbes were tested. Plant biomass, transcription of genes involved in plant defences, and insect performance were measured. In addition, the effects of the PGPR strain Pseudomonas fluorescens SS101 on plant and insect performance were tested under the influence of the various soil dilution treatments. Plant biomass showed a hump-shaped relationship with soil microbial community dilution, independent of aphid or Pseudomonas treatments. Both aphid infestation and inoculation with Pseudomonas reduced plant biomass, and led to downregulation of PR1 (salicylic acid-responsive gene) and CYP79B3 (involved in synthesis of glucosinolates). Aphid performance and gene transcription were unaffected by soil dilution. Neither the loss of rare microbial species, as caused by soil dilution, nor Pseudomonas affect the resistance of A. thaliana against M. persicae. However, both Pseudomonas survival and plant biomass respond to rare species loss. Thus, loss of rare soil microbial species can have a significant impact on both above- and below-ground organisms. © The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Anti-bacterial Efficacy of Bacteriocin Produced by Marine Bacillus subtilis Against Clinically Important Extended Spectrum Beta-Lactamase Strains and Methicillin-Resistant Staphylococcus aureus

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    Suresh Mickymaray

    2018-02-01

    Full Text Available Objective: To investigate the anti-bacterial efficacy of bacteriocin produced by Bacillus subtilis SM01 (GenBank accession no: KY612347, a Gram-positive marine bacterium, against Extended Spectrum Beta-Lactamase (ESBL producing Gram-negative pathogens Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli, and Gram-positive pathogen Methicillin-Resistant Staphylococcus aureus (MRSA. Methods: A marine bacterium was isolated from mangrove sediment from the Red Sea coast of Jeddah, Kingdom of Saudi Arabia, and identified based on its morphological, biochemical, and molecular characteristics. The bacteriocin production using this isolate was carried out in brain heart infusion broth (BHIB medium. The Anti-bacterial activity of bacteriocin was evaluated against selected ESBL strains and MRSA by the well agar method. The effects of incubation time, pH, and temperature on the Anti-bacterial activity were studied. Results: The bacteriocin Bac-SM01 produced by B. subtilis SM01 demonstrated broad-spectrum Anti-bacterial activity against both Gram-negative and -positive bacteria. The present study is the first report that the bacteriocin Bac-SM01 inhibits the growth of ESBL producing Gram-negative strains A. baumannii, P. aeruginosa, and E. coli, and a Gram-positive MRSA strain. The optimum incubation time, pH, and temperature for the Anti-bacterial activity of Bac-SM01 was 24 h, 7, and 37°C respectively. Conclusion: The overall investigation can conclude that the bacteriocin Bac-SM01 from the marine isolate Bacillus subtilis SM01 could be used as an alternative Anti-bacterial agent in pharmaceutical products.

  17. Effects of liposomal-curcumin on five opportunistic bacterial strains found in the equine hindgut - preliminary study

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    S. D. Bland

    2017-06-01

    Full Text Available Abstract Background The horse intestinal tract is sensitive and contains a highly complex microbial population. A shift in the microbial population can lead to various issues such as inflammation and colic. The use of nutraceuticals in the equine industry is on the rise and curcumin is thought to possess antimicrobial properties that may help to minimize the proliferation of opportunistic bacteria. Methods Four cecally-cannulated horses were utilized to determine the optimal dose of liposomal-curcumin (LIPC on reducing Streptococcus bovis/equinus complex (SBEC, Escherichia coli K-12, Escherichia coli general, Clostridium difficile, and Clostridium perfringens in the equine hindgut without adversely affecting cecal characteristics. In the first study cecal fluid was collected from each horse and composited for an in vitro, 24 h batch culture to examine LIPC at four different dosages (15, 20, 25, and 30 g in a completely randomized design. A subsequent in vivo 4 × 4 Latin square design study was conducted to evaluate no LIPC (control, CON or LIPC dosed at 15, 25, and 35 g per day (dosages determined from in vitro results for 9 days on the efficacy of LIPC on selected bacterial strains, pH, and volatile fatty acids. Each period was 14 days with 9 d for acclimation and 5 d withdrawal period. Results In the in vitro study dosage had no effect (P ≥ 0.42 on Clostridium strains, but as the dose increased SBEC concentrations increased (P = 0.001. Concentrations of the E. coli strain varied with dose. In vivo, LIPC’s antimicrobial properties, at 15 g, significantly decreased (P = 0.02 SBEC when compared to 25 and 35 g dosages. C. perfringens decreased linearly (P = 0.03 as LIPC dose increased. Butyrate decreased linearly (P = 0.01 as LIPC dose increased. Conclusion Further studies should be conducted with a longer dosing period to examine the antimicrobial properties of curcumin without adversely affecting cecal characteristics.

  18. A Nonluminescent and Highly Virulent Vibrio harveyi Strain Is Associated with “Bacterial White Tail Disease” of Litopenaeus vannamei Shrimp

    Science.gov (United States)

    Zhou, Junfang; Fang, Wenhong; Yang, Xianle; Zhou, Shuai; Hu, Linlin; Li, Xincang; Qi, Xinyong; Su, Hang; Xie, Layue

    2012-01-01

    Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by “white tail” and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905) was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN), white tail disease (WTD) or penaeid white tail disease (PWTD). To differentiate from such diseases as with a sign of “white tail” but of non-bacterial origin, the present disease was named as “bacterial white tail disease (BWTD)”. Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system. PMID:22383954

  19. Isolation and characterization of butachlor-catabolizing bacterial strain Stenotrophomonas acidaminiphila JS-1 from soil and assessment of its biodegradation potential.

    Science.gov (United States)

    Dwivedi, S; Singh, B R; Al-Khedhairy, A A; Alarifi, S; Musarrat, J

    2010-07-01

    Isolation, characterization and assessment of butachlor-degrading potential of bacterial strain JS-1 in soil. Butachlor-degrading bacteria were isolated using enrichment culture technique. The morphological, biochemical and genetic characteristics based on 16S rDNA sequence homology and phylogenetic analysis confirmed the isolate as Stenotrophomonas acidaminiphila strain JS-1. The strain JS-1 exhibited substantial growth in M9 mineral salt medium supplemented with 3.2 mmol l(-1) butachlor, as a sole source of carbon and energy. The HPLC analysis revealed almost complete disappearance of butachlor within 20 days in soil at a rate constant of 0.17 day(-1) and half-life (t((1/2))) of 4.0 days, following the first-order rate kinetics. The strain JS-1 in stationary phase of culture also produced 21.0 microg ml(-1) of growth hormone indole acetic acid (IAA) in the presence of 500 microg ml(-1) of tryptophan. The IAA production was stimulated at lower concentrations of butachlor, whereas higher concentrations above 0.8 mmol l(-1) were found inhibitory. The isolate JS-1 characterized as Stenotrophomonas acidaminiphila was capable of utilizing butachlor as sole source of carbon and energy. Besides being an efficient butachlor degrader, it substantially produces IAA. The bacterial strain JS-1 has a potential for butachlor remediation with a distinctive auxiliary attribute of plant growth stimulation.

  20. [Synthesis of reserve polyhydroxyalkanoates by luminescent bacteria].

    Science.gov (United States)

    Boiandin, A N; Kalacheva, G S; Rodicheva, E K; Volova, T G

    2008-01-01

    The ability of marine luminescent bacteria to synthesize polyesters of hydroxycarboxylic acids (polyhydroxyalkanoates, PHA) as reserve macromolecules was studied. Twenty strains from the collection of the luminescent bacteria CCIBSO (WDSM839) of the Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, assigned to different taxa (Photobacterium leiognathi, Ph. phosphoreum, Vibrio harveyi, and V. fischeri) were analyzed. The most productive strains were identified, and the conditions ensuring high polymer yields in batch culture (40-70% of the cell dry mass weight) were determined. The capacity of synthesizing two- and three-component polymers containing hydroxybutyric acid as the main monomer and hydroxyvaleric and hydroxyhexanoic acids was revealed in Ph. leiognathi and V. harveyi strains. The results allow luminescent microorganisms to be regarded as new producers of multicomponent polyhydroxyalkanoates.

  1. Experimental infection with different bacterial strains in larvae and juvenile Litopenaeus vannamei reared in Santa Catarina State, Brazil - doi: 10.4025/actascibiolsci.v32i3.5471 Experimental infection with different bacterial strains in larvae and juvenile Litopenaeus vannamei reared in Santa Catarina State, Brazil - doi: 10.4025/actascibiolsci.v32i3.5471

    Directory of Open Access Journals (Sweden)

    Adolfo Jatoba

    2010-09-01

    Full Text Available This study evaluated the pathogenic characteristics of bacteria isolated from Litopenaeus vannamei during an outbreak at the Laboratory of Marine Shrimp, UFSC, Santa Catarina State, Brazil. Their virulence potential in larvae and juvenile shrimp and the effects on the total haemocyte count, phenoloxidase activity and serum agglutinate titre were examined after experimental infection. Bacterial strains were isolated from larvae and adult shrimps, identified by the AP120E biochemical system as: two strains of Vibrio alginolyticus, three of Aeromonas salmonicida and one of Pasteurella multocida sp. and Pasteurella sp. All the bacterial strains isolated in this study caused mortality in shrimp. One strain of V. alginolyticus was responsible for 97.3 and 88.7% mortality in larvae and juvenil shrimps, respectively. The shrimp immunological system was influenced by experimental infection with V. alginolyticus. Decrease in the total haemocyte count and increase in the phenoloxidase activity and the serum agglutinate titre (p V. alginolyticus isolated from larvae and juvenile reared marine shrimp.This study evaluated the pathogenic characteristics of bacteria isolated from Litopenaeus vannamei during an outbreak at the Laboratory of Marine Shrimp, UFSC, Santa Catarina State, Brazil. Their virulence potential in larvae and juvenile shrimp and the effects on the total haemocyte count, phenoloxidase activity and serum agglutinate titre were examined after experimental infection. Bacterial strains were isolated from larvae and adult shrimps, identified by the AP120E biochemical system as: two strains of Vibrio alginolyticus, three of Aeromonas salmonicida and one of Pasteurella multocida sp. and Pasteurella sp. All the bacterial strains isolated in this study caused mortality in shrimp. One strain of V. alginolyticus was responsible for 97.3 and 88.7% mortality in larvae and juvenil shrimps, respectively. The shrimp immunological system was influenced by

  2. Mechanism of Excretion of a Bacterial Proteinase: Demonstration of Two Proteolytic Enzymes Produced by a Sarcina Strain (Coccus P)

    Energy Technology Data Exchange (ETDEWEB)

    SARNER, NITZA Z; BISSELL, MINA J; GIROLAMO, MARIO Di; GORINI, LUIGI

    1970-06-29

    A Sarcina strain (Coccus P) produces two proteolytic enzymes. One is found only extracellularly, is far more prevalent, and is actively excreted during exponential growth. It is the enzyme responsible for the known strong proteolytic activity of the cultures of this strain. A second protease is, however, produced which remains associated with the intact cells but is released by the protoplasts. The two enzymes appear unrelated in their derivation. Calcium ions play an essential role in preventing autodigestion of the excreted enzyme. Bacterial proteins are found outside the cell boundary as a consequence either of passive processes such as leakage or lysis or of active excretion. Under conditions in which leakage and lysis do not occur, as during exponential growth, the cell boundary is a barrier causing a complete separation of the bulk of the intracellular proteins from the one or very few extracellular proteins, with no trace of either type being detectable on the wrong side of the boundary. Since in bacteria there is no evidence of protein being produced other than internally, the separation into intraand extracellular proteins should occur after peptide chain formation. The question arises as to whether the structure of the cell boundary or that of the excreted proteins themselves determines this separation. Coccus P, a Sarcina closely related to Micrococcus lysodeikticus (3), produces an extracellular proteinase during the exponential phase of growth so that the process appears to be active excretion. The organism grows exponentially in a defined synthetic medium (12) to relatively high cell density (10{sup 9} cells/ml); therefore the mechanism of excretion can be studied over an extended period of time without the difficulties of changing growth rates. Coagulation of reconstituted skim milk provides a simple and sensitive assay for enzyme activity (I 1). The extracellular proteinase has also been purified and partially characterized (6-8). It has been shown

  3. The efficacy of different anti-microbial metals at preventing the formation of, and eradicating bacterial biofilms of pathogenic indicator strains.

    Science.gov (United States)

    Gugala, Natalie; Lemire, Joe A; Turner, Raymond J

    2017-06-01

    The emergence of multidrug-resistant pathogens and the prevalence of biofilm-related infections have generated a demand for alternative anti-microbial therapies. Metals have not been explored in adequate detail for their capacity to combat infectious disease. Metal compounds can now be found in textiles, medical devices and disinfectants-yet, we know little about their efficacy against specific pathogens. To help fill this knowledge gap, we report on the anti-microbial and antibiofilm activity of seven metals: silver, copper, titanium, gallium, nickel, aluminum and zinc against three bacterial strains, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. To evaluate the capacity of metal ions to prevent the growth of, and eradicate biofilms and planktonic cells, bacterial cultures were inoculated in the Calgary Biofilm Device (minimal biofilm eradication concentration) in the presence of the metal salts. Copper, gallium and titanium were capable of preventing planktonic and biofilm growth, and eradicating established biofilms of all tested strains. Further, we observed that the efficacies of the other tested metal salts displayed variable efficacy against the tested strains. Further, contrary to the enhanced resistance anticipated from bacterial biofilms, particular metal salts were observed to be more effective against biofilm communities versus planktonic cells. In this study, we have demonstrated that the identity of the bacterial strain must be considered before treatment with a particular metal ion. Consequent to the use of metal ions as anti-microbial agents to fight multidrug-resistant and biofilm-related infections increases, we must aim for more selective deployment in a given infectious setting.

  4. Effect Of GAMMA-Irradiation On Production And Characteristics Of Chitosan Produced From Crustacean Waste By Using Some Bacterial Strains

    International Nuclear Information System (INIS)

    INAS ISMAIL MAHMOUD RAAFAT

    2015-01-01

    The main study focused on separation of chitin from crustacean waste (shrimp shell) using some proteolytic bacterial isolates. After that, chitosan was obtained by deactylation and its characteristics were studied using some characterizing tools. The produced chitosan was degraded to different molecular weights and evaluated as an antibacterial agent. Seventy bacterial isolates were obtained from different sources (soil, plant roots and shrimp shell waste) and tested for their ability to produce proteolytic enzymes. One isolate was selected, due its high proteolytic activity and ability to grow using shrimp as carbon and nitrogen source on shrimp shell agar medium and identified as Bacillus subtilis NA12 by 16S-rRNA gene sequences with a high degree of similarity (99 %) as a gene bank database. Factors affecting deproteinization (DP) and demineralization (DM) efficiency of shrimp shell waste (SSW) (carbon source and its optimal concentration, shrimp shell waste concentration, inoculum size and fermentation time) were studied. The most efficient DP (92.40 %) and DM (81.37 %) of SSW by B. subtilis NA12 were sucrose 10 % (w/v) and inoculum size 15 % (v/v 35 x 108 CFU/ml ) to ferment shrimp shell waste 5 % (w/v) for 6 days of fermentation time. The effect of γ-irradiation on the performance of selected bacterial strain was studied to maximize chitin yield. Box-Behnken design using response surface methodology was employed to establish the relationship between the previous variables, implied that the model was highly significant. It was found that a sucrose concentration of 5 % (w/v), SSW of 12.5 % (w/v), inoculum size of 10 % (v/v) and fermentation time of 7 days; had a predicted value of DP of 97.65 % whereas the actual experiment gave 96.37 %. The predicted value of DM was 82.94 % whereas the actual experiment gave 82.19 %. Chitosan polymer was successfully prepared by the deacetylation reaction from fermented shrimp shell waste (SSW) by Bacillus subtilis NA12

  5. The efficacy of Carica papaya leaf extract on some bacterial and a fungal strain by well diffusion method

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    C. Baskaran

    2012-10-01

    Full Text Available Objective: To investigate the antimicrobial activity and phytochemical screening Ethanol, methanol, Ethyl acetate, acetone, chloroform, Petroleum ether, hexane, hot water, and extracts of Carica papaya. Methods: The aim of the present study was to evaluate the qualitative analysis of phytochemicals and antimicrobial activity of various solvent extracts of Carica papaya. The antimicrobial activities of different solvent extracts of Carica papaya were tested against the Gram-positive and Gram-negative bacterial strains and fungus by observing the zone of inhibition. The Gram-positive bacteria used in the test were Staphylococcus aureus, Bacillus cereus and Micrococcus luteus, and the Gram-negative bacteria were Escherichia coli, and Klebsiella pneumoniae, fungus like Aspergillus niger, Aspergillus flavus, Candida albicans, Candida tropicalis, Cryptococcus neoformans, and Candida kefyr. Results: It was observed that ethanol, methanol, ethyl acetate, aceton, chloroform, petroleum ether, hexane and aquas extracts showed activity against bacteria and fungus. The chloroform extract of Carica papaya showed more activity against Micrococcus luteus, zone of diameter 15.17暲0.29mm and acetone extract of Carica papaya showed more activity against Candida albicans, zone of diameter 11.23暲0.25mm compared to other solvent extracts. Conclusions: In this study chloroform extract in bacteria and acetone extract in fungus showed a varying degree of inhibition to the growth of tested organism, than Ethanol, methanol, Ethyl acetate, Petroleum ether, hexane and hot water extracts. The results confirmed the presence of antibacterial and antifungal activity of Carica papaya extract against various human pathogenic bacteria. Presences of phytochemical and antimicrobial activity are confirmed.

  6. Colonization of Vitis vinifera by a green fluorescence protein-labeled, gfp-marked strain of Xylophilus ampelinus, the causal agent of bacterial necrosis of grapevine.

    Science.gov (United States)

    Grall, Sophie; Manceau, Charles

    2003-04-01

    The dynamics of Xylophilus ampelinus were studied in Vitis vinifera cv. Ugni blanc using gfp-marked bacterial strains to evaluate the relative importance of epiphytic and endophytic phases of plant colonization in disease development. Currently, bacterial necrosis of grapevine is of economic importance in vineyards in three regions in France: the Cognac, Armagnac, and Die areas. This disease is responsible for progressive destruction of vine shoots, leading to their death. We constructed gfp-marked strains of the CFBP2098 strain of X. ampelinus for histological studies. We studied the colonization of young plants of V. vinifera cv. Ugni blanc by X. ampelinus after three types of artificial contamination in a growth chamber and in a greenhouse. (i) After wounding of the stem and inoculation, the bacteria progressed down to the crown through the xylem vessels, where they organized into biofilms. (ii) When the bacteria were forced into woody cuttings, they rarely colonized the emerging plantlets. Xylem vessels could play a key role in the multiplication and conservation of the bacteria, rather than being a route for plant colonization. (iii) When bacterial suspensions were sprayed onto the plants, bacteria progressed in two directions: both in emerging organs and down to the crown, thus displaying the importance of epiphytic colonization in disease development.

  7. DNA microarray-based genome comparison of a pathogenic and a nonpathogenic strain of Xylella fastidiosa delineates genes important for bacterial virulence.

    Science.gov (United States)

    Koide, Tie; Zaini, Paulo A; Moreira, Leandro M; Vêncio, Ricardo Z N; Matsukuma, Adriana Y; Durham, Alan M; Teixeira, Diva C; El-Dorry, Hamza; Monteiro, Patrícia B; da Silva, Ana Claudia R; Verjovski-Almeida, Sergio; da Silva, Aline M; Gomes, Suely L

    2004-08-01

    Xylella fastidiosa is a phytopathogenic bacterium that causes serious diseases in a wide range of economically important crops. Despite extensive comparative analyses of genome sequences of Xylella pathogenic strains from different plant hosts, nonpathogenic strains have not been studied. In this report, we show that X. fastidiosa strain J1a12, associated with citrus variegated chlorosis (CVC), is nonpathogenic when injected into citrus and tobacco plants. Furthermore, a DNA microarray-based comparison of J1a12 with 9a5c, a CVC strain that is highly pathogenic and had its genome completely sequenced, revealed that 14 coding sequences of strain 9a5c are absent or highly divergent in strain J1a12. Among them, we found an arginase and a fimbrial adhesin precursor of type III pilus, which were confirmed to be absent in the nonpathogenic strain by PCR and DNA sequencing. The absence of arginase can be correlated to the inability of J1a12 to multiply in host plants. This enzyme has been recently shown to act as a bacterial survival mechanism by down-regulating host nitric oxide production. The lack of the adhesin precursor gene is in accordance with the less aggregated phenotype observed for J1a12 cells growing in vitro. Thus, the absence of both genes can be associated with the failure of the J1a12 strain to establish and spread in citrus and tobacco plants. These results provide the first detailed comparison between a nonpathogenic strain and a pathogenic strain of X. fastidiosa, constituting an important step towards understanding the molecular basis of the disease.

  8. Screening of bacterial strains capable of converting biodiesel-derived raw glycerol into 1,3-propanediol, 2,3-butanediol and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Metsoviti, Maria; Paramithiotis, Spiros; Drosinos, Eleftherios H.; Galiotou-Panayotou, Maria; Nychas, George-John E.; Papanikolaou, Seraphim [Department of Food Science and Technology, Agricultural University of Athens, Athens (Greece); Zeng, An-Ping [Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology (TUHH), Hamburg (Germany)

    2012-02-15

    The ability of bacterial strains to assimilate glycerol derived from biodiesel facilities to produce metabolic compounds of importance for the food, textile and chemical industry, such as 1,3-propanediol (PD), 2,3-butanediol (BD) and ethanol (EtOH), was assessed. The screening of 84 bacterial strains was performed using glycerol as carbon source. After initial trials, 12 strains were identified capable of consuming raw glycerol under anaerobic conditions, whereas 5 strains consumed glycerol under aerobiosis. A plethora of metabolic compounds was synthesized; in anaerobic batch-bioreactor cultures PD in quantities up to 11.3 g/L was produced by Clostridium butyricum NRRL B-23495, while the respective value was 10.1 g/L for a newly isolated Citrobacter freundii. Adaptation of Cl. butyricum at higher initial glycerol concentration resulted in a PD{sub max} concentration of {proportional_to}32 g/L. BD was produced by a new Enterobacter aerogenes isolate in shake-flask experiments, under fully aerobic conditions, with a maximum concentration of {proportional_to}22 g/L which was achieved at an initial glycerol quantity of 55 g/L. A new Klebsiella oxytoca isolate converted waste glycerol into mixtures of PD, BD and EtOH at various ratios. Finally, another new C. freundii isolate converted waste glycerol into EtOH in anaerobic batch-bioreactor cultures with constant pH, achieving a final EtOH concentration of 14.5 g/L, a conversion yield of 0.45 g/g and a volumetric productivity of {proportional_to}0.7 g/L/h. As a conclusion, the current study confirmed the utilization of biodiesel-derived raw glycerol as an appropriate substrate for the production of PD, BD and EtOH by several newly isolated bacterial strains under different experimental conditions. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Feldspar, Infrared Stimulated Luminescence

    DEFF Research Database (Denmark)

    Jain, Mayank

    2014-01-01

    This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

  10. Insights from the Genome Sequence of Acidovorax citrulli M6, a Group I Strain of the Causal Agent of Bacterial Fruit Blotch of Cucurbits.

    Science.gov (United States)

    Eckshtain-Levi, Noam; Shkedy, Dafna; Gershovits, Michael; Da Silva, Gustavo M; Tamir-Ariel, Dafna; Walcott, Ron; Pupko, Tal; Burdman, Saul

    2016-01-01

    Acidovorax citrulli is a seedborne bacterium that causes bacterial fruit blotch of cucurbit plants including watermelon and melon. A. citrulli strains can be divided into two major groups based on DNA fingerprint analyses and biochemical properties. Group I strains have been generally isolated from non-watermelon cucurbits, while group II strains are closely associated with watermelon. In the present study, we report the genome sequence of M6, a group I model A. citrulli strain, isolated from melon. We used comparative genome analysis to investigate differences between the genome of strain M6 and the genome of the group II model strain AAC00-1. The draft genome sequence of A. citrulli M6 harbors 139 contigs, with an overall approximate size of 4.85 Mb. The genome of M6 is ∼500 Kb shorter than that of strain AAC00-1. Comparative analysis revealed that this size difference is mainly explained by eight fragments, ranging from ∼35-120 Kb and distributed throughout the AAC00-1 genome, which are absent in the M6 genome. In agreement with this finding, while AAC00-1 was found to possess 532 open reading frames (ORFs) that are absent in strain M6, only 123 ORFs in M6 were absent in AAC00-1. Most of these M6 ORFs are hypothetical proteins and most of them were also detected in two group I strains that were recently sequenced, tw6 and pslb65. Further analyses by PCR assays and coverage analyses with other A. citrulli strains support the notion that some of these fragments or significant portions of them are discriminative between groups I and II strains of A. citrulli. Moreover, GC content, effective number of codon values and cluster of orthologs' analyses indicate that these fragments were introduced into group II strains by horizontal gene transfer events. Our study reports the genome sequence of a model group I strain of A. citrulli, one of the most important pathogens of cucurbits. It also provides the first comprehensive comparison at the genomic level between the

  11. The influence of Photorhabdus luminescens strains and form variants on the reproduction and bacterial retention of Heterorhabditis megidis

    NARCIS (Netherlands)

    Gerritsen, L.J.M.; Smits, P.H.

    1997-01-01

    The preference of nematodes for feeding on, and retention of strains and form variants of symbionts was tested. Heterorhabditis megidis strains DH-SH1 (= HSH) and NLH-E87.3 (= HE) could multiply on the primary forms of both symbionts. Photorhabdus luminescens strains PSH/1 and PE/1, respectively,

  12. Whole genome sequencing options for bacterial strain typing and epidemiologic analysis based on single nucleotide polymorphism versus gene-by-gene-based approaches.

    Science.gov (United States)

    Schürch, A C; Arredondo-Alonso, S; Willems, R J L; Goering, R V

    2018-04-01

    Whole genome sequence (WGS)-based strain typing finds increasing use in the epidemiologic analysis of bacterial pathogens in both public health as well as more localized infection control settings. This minireview describes methodologic approaches that have been explored for WGS-based epidemiologic analysis and considers the challenges and pitfalls of data interpretation. Personal collection of relevant publications. When applying WGS to study the molecular epidemiology of bacterial pathogens, genomic variability between strains is translated into measures of distance by determining single nucleotide polymorphisms in core genome alignments or by indexing allelic variation in hundreds to thousands of core genes, assigning types to unique allelic profiles. Interpreting isolate relatedness from these distances is highly organism specific, and attempts to establish species-specific cutoffs are unlikely to be generally applicable. In cases where single nucleotide polymorphism or core gene typing do not provide the resolution necessary for accurate assessment of the epidemiology of bacterial pathogens, inclusion of accessory gene or plasmid sequences may provide the additional required discrimination. As with all epidemiologic analysis, realizing the full potential of the revolutionary advances in WGS-based approaches requires understanding and dealing with issues related to the fundamental steps of data generation and interpretation. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Preliminary data on antibacterial activity of Echinacea purpurea-associated bacterial communities against Burkholderia cepacia complex strains, opportunistic pathogens of Cystic Fibrosis patients.

    Science.gov (United States)

    Chiellini, Carolina; Maida, Isabel; Maggini, Valentina; Bosi, Emanuele; Mocali, Stefano; Emiliani, Giovanni; Perrin, Elena; Firenzuoli, Fabio; Mengoni, Alessio; Fani, Renato

    2017-03-01

    Burkholderia cepacia complex bacteria (Bcc) represent a serious threat for immune-compromised patient affected by Cystic Fibrosis (CF) since they are resistant to many substances and to most antibiotics. For this reason, the research of new natural compounds able to inhibit the growth of Bcc strains has raised new interest during the last years. A source of such natural compounds is represented by medicinal plants and, in particular, by bacterial communities associated with these plants able to produce molecules with antimicrobial activity. In this work, a panel of 151 (endophytic) bacteria isolated from three different compartments (rhizospheric soil, roots, and stem/leaves) of the medicinal plant Echinacea purpurea were tested (using the cross-streak method) for their ability to inhibit the growth of 10 Bcc strains. Data obtained revealed that bacteria isolated from the roots of E. purpurea are the most active in the inhibition of Bcc strains, followed by bacteria isolated from the rhizospheric soil, and endophytes from stem/leaf compartment. At the same time, Bcc strains of environmental origin showed a higher resistance toward inhibition than the Bcc strains with clinical (i.e. CF patients) origin. Differences in the inhibition activity of E. purpurea-associated bacteria are mainly linked to the environment -the plant compartment- rather than to their taxonomical position. Copyright © 2016 Elsevier GmbH. All rights reserved.

  14. Enzymes produced by halotolerant spore-forming gram-positive bacterial strains isolated from a resting habitat (Restinga de Jurubatiba) in Rio de Janeiro, Brazil: focus on proteases.

    Science.gov (United States)

    D Santos, Anderson Fragoso; Pacheco, Clarissa Almeida; Valle, Roberta D Santos; Seldin, Lucy; D Santos, André Luis Souza

    2014-12-01

    The screening for hydrolases-producing, halotolerant, and spore-forming gram-positive bacteria from the root, rhizosphere, and non-rhizosphere soil of Blutaparon portulacoides, a plant found in the Restinga de Jurubatiba located at the northern region of Rio de Janeiro State, Brazil, resulted in the isolation of 22 strains. These strains were identified as Halobacillus blutaparonensis (n = 2), Oceanobacillus picturae (n = 5), and Oceanobacillus iheyensis (n = 15), and all showed the ability to produce different extracellular enzymes. A total of 20 isolates (90.9 %) showed activity for protease, 5 (22.7 %) for phytase, 3 (13.6 %) for cellulase, and 2 (9.1 %) for amylase. Some bacterial strains were capable of producing three (13.6 %) or two (9.1 %) distinct hydrolytic enzymes. However, no bacterial strain with ability to produce esterase and DNase was observed. The isolate designated M9, belonging to the species H. blutaparonensis, was the best producer of protease and also yielded amylase and phytase. This strain was chosen for further studies regarding its protease activity. The M9 strain produced similar amounts of protease when grown either without or with different NaCl concentrations (from 0.5 to 10 %). A simple inspection of the cell-free culture supernatant by gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of three major alkaline proteases of 40, 50, and 70 kDa, which were fully inhibited by phenylmethylsulfonyl fluoride (PMSF) and tosyl-L-phenylalanine chloromethyl ketone (TPCK) (two classical serine protease inhibitors). The secreted proteases were detected in a wide range of temperature (from 4 to 45 °C) and their hydrolytic activities were stimulated by NaCl (up to 10 %). The serine proteases produced by the M9 strain cleaved gelatin, casein, albumin, and hemoglobin, however, in different extensions. Collectively, these results suggest the potential use of the M9 strain in biotechnological

  15. A multi-channel bioluminescent bacterial biosensor for the on-line detection of metals and toxicity. Part I: design and optimization of bioluminescent bacterial strains

    Energy Technology Data Exchange (ETDEWEB)

    Charrier, Thomas; Durand, Marie-Jose; Jouanneau, Sulivan; Thouand, Gerald [UMR CNRS 6144 GEPEA, CBAC, Nantes University, PRES UNAM, Campus de la Courtaisiere-IUT, La Roche-sur-Yon cedex (France); Dion, Michel [UMR CNRS 6204, Nantes University, PRES UNAM, Biotechnologie, Biocatalyse, Bioregulation, 2, Rue de la Houssiniere, BP 92208, Nantes cedex 3 (France); Pernetti, Mimma; Poncelet, Denis [ONIRIS-ENITIAA, UMR CNRS GEPEA, Rue de la Geraudiere, BP 82225, Nantes cedex 3 (France)

    2011-05-15

    This study describes the construction of inducible bioluminescent strains via genetic engineering along with their characterization and optimization in the detection of heavy metals. Firstly, a preliminary comparative study enabled us to select a suitable carbon substrate from pyruvate, glucose, citrate, diluted Luria-Bertani, and acetate. The latter carbon source provided the best induction ratios for comparison. Results showed that the three constructed inducible strains, Escherichia coli DH1 pBzntlux, pBarslux, and pBcoplux, were usable when conducting a bioassay after a 14-h overnight culture at 30 C. Utilizing these sensors gave a range of 12 detected heavy metals including several cross-detections. Detection limits for each metal were often close to and sometimes lower than the European standards for water pollution. Finally, in order to maintain sensitive bacteria within the future biosensor-measuring cell, the agarose immobilization matrix was compared to polyvinyl alcohol (PVA). Agarose was selected because the detection limits of the bioluminescent strains were not affected, in contrast to PVA. Specific detection and cross-detection ranges determined in this study will form the basis of a multiple metals detection system by the new multi-channel Lumisens3 biosensor. (orig.)

  16. Luminescence and energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Blasse, G; Bleijenberg, K C; Powell, R C

    1980-01-01

    This paper deals with the luminescence of uranate centres in solids. The luminescence properties are influenced by the coordination number of the hexavalent uranium ion and by the crystallographic surroundings of the uranate centre. Transitions playing a role in the luminescence processes within the octahedral UO/sub 6//sup 6 -/ group are discussed using the results from both theoretical and experimental studies on another octahedral uranium complex: UF/sub 6/. The luminescence of the octahedral uranate group in oxidic compounds is discussed. Attention is paid to the vibrational structure, which is observed in the luminescence spectra at low temperatures and to the temperature quenching of the luminescence. The temperature quenching of the uranate luminescence in uranium-doped tungstates with ordered perovskite structure can be described in terms of a three state single configurational coordinate diagram. The complicated luminescence spectra of uranium-activated sodium fluoride (NaF-U) crystals have been unraveled using chemical variation of the crystal compositions and using site selective laser excitation techniques. Four different luminescent uranate centres have been observed in NaF-U. A model for the configurations of the luminescent centres has been deduced using the results from ionic conductivity experiments.

  17. View of the bacterial strains of Escherichia coli M-17 and its interaction with the nanoparticles of zinc oxide by means of atomic force microscopy

    International Nuclear Information System (INIS)

    Sagitova, A; Yaminsky, I; Meshkov, G

    2016-01-01

    Visualization of the structure of biological objects plays a key role in medicine, biotechnology, nanotechnology and IT-technology. Atomic force microscopy (AFM) is a promising method of studying of objects’ morphology and structure. In this work, AFM was used to determine the size and shape of the bacterial strains of Escherichia coli M-17 and visualization its interaction with the nanoparticles of zinc oxide. The suspension of E.coli bacteria was applied to natural mica and studied by contact mode using the FemtoScan multifunctional scanning probe microscope. (paper)

  18. View of the bacterial strains of Escherichia coli M-17 and its interaction with the nanoparticles of zinc oxide by means of atomic force microscopy

    Science.gov (United States)

    Sagitova, A.; Yaminsky, I.; Meshkov, G.

    2016-08-01

    Visualization of the structure of biological objects plays a key role in medicine, biotechnology, nanotechnology and IT-technology. Atomic force microscopy (AFM) is a promising method of studying of objects’ morphology and structure. In this work, AFM was used to determine the size and shape of the bacterial strains of Escherichia coli M-17 and visualization its interaction with the nanoparticles of zinc oxide. The suspension of E.coli bacteria was applied to natural mica and studied by contact mode using the FemtoScan multifunctional scanning probe microscope.

  19. Bacterial membrane activity of a-peptide/b-peptoid chimeras: Influence of amino acid composition and chain length on the activity against different bacterial strains

    DEFF Research Database (Denmark)

    Hein-Kristensen, Line; Knapp, Kolja M; Franzyk, Henrik

    2011-01-01

    and subsequent killing is usually not tested. In this report, six α-peptide/β-peptoid chimeras were examined for the effect of amino acid/peptoid substitutions and chain length on the membrane perturbation and subsequent killing of food-borne and clinical bacterial isolates. RESULTS: All six AMP analogues...... acid only had a minor effect on MIC values, whereas chain length had a profound influence on activity. All chimeras were less active against Serratia marcescens (MICs above 46 μM). The chimeras were bactericidal and induced leakage of ATP from Staphylococcus aureus and S. marcescens with similar time...... of onset and reduction in the number of viable cells. EDTA pre-treatment of S. marcescens and E. coli followed by treatment with chimeras resulted in pronounced killing indicating that disintegration of the Gram-negative outer membrane eliminated innate differences in susceptibility. Chimera chain length...

  20. Role of the Genes of Type VI Secretion System in Virulence of Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae Strain RS-2

    Directory of Open Access Journals (Sweden)

    Md. Mahidul Islam Masum

    2017-09-01

    Full Text Available The Type VI secretion system (T6SS is a class of macromolecular machine that is required for the virulence of gram-negative bacteria. However, it is still not clear what the role of T6SS in the virulence of rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa is. The aim of the current study was to investigate the contribution of T6SS in Aaa strain RS2 virulence using insertional deletion mutation and complementation approaches. This strain produced weak virulence but contains a complete T6SS gene cluster based on a genome-wide analysis. Here we compared the virulence-related phenotypes between the wild-type (RS-2 and 25 T6SS mutants, which were constructed using homologous recombination methods. The mutation of 15 T6SS genes significantly reduced bacterial virulence and the secretion of Hcp protein. Additionally, the complemented 7 mutations ΔpppA, ΔclpB, Δhcp, ΔdotU, ΔicmF, ΔimpJ, and ΔimpM caused similar virulence characteristics as RS-2. Moreover, the mutant ΔpppA, ΔclpB, ΔicmF, ΔimpJ and ΔimpM genes caused by a 38.3~56.4% reduction in biofilm formation while the mutants ΔpppA, ΔclpB, ΔicmF and Δhcp resulted in a 37.5~44.6% reduction in motility. All together, these results demonstrate that T6SS play vital roles in the virulence of strain RS-2, which may be partially attributed to the reductions in Hcp secretion, biofilm formation and motility. However, differences in virulence between strain RS-1 and RS-2 suggest that other factors may also be involved in the virulence of Aaa.

  1. Role of the Genes of Type VI Secretion System in Virulence of Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae Strain RS-2.

    Science.gov (United States)

    Masum, Md Mahidul Islam; Yang, Yingzi; Li, Bin; Olaitan, Ogunyemi Solabomi; Chen, Jie; Zhang, Yang; Fang, Yushi; Qiu, Wen; Wang, Yanli; Sun, Guochang

    2017-09-21

    The Type VI secretion system (T6SS) is a class of macromolecular machine that is required for the virulence of gram-negative bacteria. However, it is still not clear what the role of T6SS in the virulence of rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa) is. The aim of the current study was to investigate the contribution of T6SS in Aaa strain RS2 virulence using insertional deletion mutation and complementation approaches. This strain produced weak virulence but contains a complete T6SS gene cluster based on a genome-wide analysis. Here we compared the virulence-related phenotypes between the wild-type (RS-2) and 25 T6SS mutants, which were constructed using homologous recombination methods. The mutation of 15 T6SS genes significantly reduced bacterial virulence and the secretion of Hcp protein. Additionally, the complemented 7 mutations Δ pppA , Δ clpB , Δ hcp , Δ dotU , Δ icmF , Δ impJ , and Δ impM caused similar virulence characteristics as RS-2. Moreover, the mutant Δ pppA , Δ clpB , Δ icmF , Δ impJ and Δ impM genes caused by a 38.3~56.4% reduction in biofilm formation while the mutants Δ pppA , Δ clpB , Δ icmF and Δ hcp resulted in a 37.5~44.6% reduction in motility. All together, these results demonstrate that T6SS play vital roles in the virulence of strain RS-2, which may be partially attributed to the reductions in Hcp secretion, biofilm formation and motility. However, differences in virulence between strain RS-1 and RS-2 suggest that other factors may also be involved in the virulence of Aaa.

  2. Luminescent beam stop

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Diane; Morton, Simon A.

    2017-10-25

    This disclosure provides systems, methods, and apparatus related to beam stops. In one aspect, a device comprises a luminescent material, a beam stop plate, and an optical fiber. The luminescent material is a parallelepiped having a first side and a second side that are squares and having a third side that is a rectangle or a square. The first side and the second side are perpendicular to the third side. The beam stop plate is attached to the first side of the luminescent material. The optical fiber has a first end and a second end, with the first end of the optical fiber attached to the third side of the luminescent material.

  3. Luminescence detection of shellfish

    International Nuclear Information System (INIS)

    Sanderson, D.C.W.; Carmichael, L.A.; Spencer, J.Q.; Naylor, J.D.

    1996-01-01

    The Scottish Universities Research and Reactor Centre (SURRC) has been active in the development and application of luminescence techniques in the detection of irradiated foods, in support of UK legislation. Thermoluminescence (TL), photostimulated luminescence (PSL) and photo-transfer luminescence (PTTL) are radiation-specific phenomena which arise due to energy stored by trapped charge carriers following irradiation. The energy released following stimulation is accompanied by detectable luminescence. The TL method involves preparation of pure silicate extracts from the sample and subsequent TL analysis, whereas PSL uses stimulation by electromagnetic radiation (visible, or near visible wavelengths) thus avoiding heating the sample. (author)

  4. Construction and evaluation of an exopolysaccharide-producing engineered bacterial strain by protoplast fusion for microbial enhanced oil recovery.

    Science.gov (United States)

    Sun, Shanshan; Luo, Yijing; Cao, Siyuan; Li, Wenhong; Zhang, Zhongzhi; Jiang, Lingxi; Dong, Hanping; Yu, Li; Wu, Wei-Min

    2013-09-01

    Enterobacter cloacae strain JD, which produces water-insoluble biopolymers at optimal temperature of 30°C, and a thermophilic Geobacillus strain were used to construct an engineered strain for exopolysaccharide production at high temperatures by protoplast fusion. The obtained fusant strain ZR3 produced exopolysaccharides at up to 45°C with optimal growth temperature at 35°C. The fusant produced exopolysaccharides of approximately 7.5 g/L or more at pH between 7.0 and 9.0. The feasibility of the enhancement of crude oil recovery with the fusant was tested in a sand-packed column at 40°C. The results demonstrated that bioaugmentation of the fusant was promising approach for MEOR. Mass growth of the fusant was confirmed in fermentor tests. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Accelerating the sludge disintegration potential of a novel bacterial strain Planococcus jake 01 by CaCl2 induced deflocculation.

    Science.gov (United States)

    Kavitha, S; Saranya, T; Kaliappan, S; Adish Kumar, S; Yeom, Ick Tae; Rajesh Banu, J

    2015-01-01

    The present study investigates the impacts of phase separated disintegration through CaCl2 (calcium chloride) mediated biosurfactant producing bacterial pretreatment. In the initial phase of the study, the flocs were disintegrated (deflocculation) with 0.06g/gSS of CaCl2. In the subsequent phase, the sludge biomass was disintegrated (cell disintegration) through potent biosurfactant producing new novel bacteria, Planococcus jake 01. The pretreatment showed that suspended solids reduction and chemical oxygen demand solubilization for deflocculated - bacterially pretreated sludge was found to be 17.14% and 14.14% which were comparatively higher than flocculated sludge (treated with bacteria alone). The biogas yield potential of deflocculated - bacterially pretreated, flocculated, and control sludges were observed to be 0.322(L/gVS), 0.225(L/gVS) and 0.145(L/gVS) respectively. To our knowledge, this is the first study to present the thorough knowledge of biogas production potential through a novel phase separated biosurfactant bacterial pretreatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Evaluation of assembling methods on determination of whole genome sequence of Xylella fastidiosa blueberry bacterial leaf scorch strain

    Science.gov (United States)

    Blueberry bacterial leaf scorch (BBLS) disease, a threat to blueberry production in the Southern USA and potentially elsewhere, is caused by Xylella fastidiosa. Efficient control of BBLS requires knowledge of the pathogen. However, this is challenging because Xylella fastidiosa is difficult to cultu...

  7. Complementary Mechanisms for Degradation of Inulin-Type Fructans and Arabinoxylan Oligosaccharides among Bifidobacterial Strains Suggest Bacterial Cooperation.

    Science.gov (United States)

    Rivière, Audrey; Selak, Marija; Geirnaert, Annelies; Van den Abbeele, Pieter; De Vuyst, Luc

    2018-05-01

    Inulin-type fructans (ITF) and arabinoxylan oligosaccharides (AXOS) are broken down to different extents by various bifidobacterial strains present in the human colon. To date, phenotypic heterogeneity in the consumption of these complex oligosaccharides at the strain level remains poorly studied. To examine mechanistic variations in ITF and AXOS constituent preferences present in one individual, ITF and AXOS consumption by bifidobacterial strains isolated from the simulator of the human intestinal microbial ecosystem (SHIME) after inoculation with feces from one healthy individual was investigated. Among the 18 strains identified, four species-independent clusters displaying different ITF and AXOS degradation mechanisms and preferences were found. Bifidobacterium bifidum B46 showed limited growth on all substrates, whereas B. longum B24 and B. longum B18 could grow better on short-chain-length fractions of fructooligosaccharides (FOS) than on fructose. B. longum B24 could cleave arabinose substituents of AXOS extracellularly, without using the AXOS-derived xylose backbones, whereas B. longum B18 was able to consume oligosaccharides (up to xylotetraose) preferentially and consumed AXOS to a limited extent. B. adolescentis B72 degraded all fractions of FOS simultaneously, partially degraded inulin, and could use xylose backbones longer than xylotetraose extracellularly. The strain-specific degradation mechanisms were suggested to be complementary and indicated resource partitioning. Specialization in the degradation of complex carbohydrates by bifidobacteria present on the individual level could have in vivo implications for the successful implementation of ITF and AXOS, aiming at bifidogenic and/or butyrogenic effects. Finally, this work shows the importance of taking microbial strain-level differences into account in gut microbiota research. IMPORTANCE It is well known that bifidobacteria degrade undigestible complex polysaccharides, such as ITF and AXOS, in the

  8. The effect of new probiotic strain Lactobacillus plantarum on counts of coliforms, lactobacilli and bacterial enzyme activities in rats exposed to N,N-dimethylhydrazine (chemical carcinogen

    Directory of Open Access Journals (Sweden)

    Denisa Čokášová

    2012-01-01

    Full Text Available The aim of the present study was to evaluate the effect of the new probiotic strain Lactobacillus plantarum on chemically induced carcinogenesis in rats. Sprague dowley rats (n = 33 were divided into control and experimental groups and were fed a conventional laboratory diet. In the experimental group, rats were treated with the probiotic at the dose of 1 × 109 CFU (colony-forming units/ml. Two weeks after the beginning of the trial, N,N-dimethylhydrazine (chemical carcinogen injections were applied s.c. at the dose of 21 mg/kg b.w., 5 × weekly. At the end of the 8-month experimental period, faeces samples were taken from the rats and used for laboratory analysis. The counts of lactobacilli and coliforms and bacterial enzyme activity were determined. The probiotic strain L. plantarum as single species or in combination with oil (Lini oleum virginale decreased the count of total coliforms and increased lactobacilli in faeces of rats. Application of probiotic microorganisms significantly (P < 0.05 decreased the activities of bacterial enzymes (β-galactosidase and β-glucuronidase compared to the control group rats. The results of this study indicate that probiotic microorganisms could exert a preventive effect on colon carcinogenesis induced by N,N-dimethylhydrazine.

  9. Evaluation of Anti-adherent Activity of Excretions of Irradiated Lucilia sericata Maggot and Certain Essential Oils against Some Pathogenic Bacterial Strains

    International Nuclear Information System (INIS)

    Eltablawy, S.Y.; Amin, M.M.

    2011-01-01

    Essential Oils are widely used for their medicinal properties. They block adhesion and colonization of pathogenic microbes to epithelial cells which associated with bacterial resistance to antibiotics. So, this study investigates the effect of Lu cilia sacarato (flesh fly-an ectoparasitic) excretions of non-irradiated and irradiated maggot and some essential oils on biofilm formation by tube method, antimicrobial susceptibility by agar disc diffusion method as well as on their anti-adherent activity by spectrophotometric method. The results showed that excretions and secretions (E/S) of non-irradiated and irradiated maggots (at 20 Gy), as well as (clove and cinnamon oils) did not have antibacterial activity against the tested bacterial strains Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (St. aureus) and Staphylococcus epidermidis (St. epidermidis) except marjoram oil which has low antimicrobial activity against all the tested strains. The results also showed that the most potent oil was clove which decrease biofilm of P. aeruginosa by 83%, followed by marjoram (69%), then E/S of non-irradiated maggots (66%). Whiles, biofilm was less affected by cinnamon oil and E/S of irradiated maggots by 50 % and 36%, respectively. In addition, clove oil and E/S of non-irradiated maggots affect the pre-adhered biofilm of P. aeruginosa by 57 and 45 %, respectively. Conclusion: Clove oil flowed by marjoram had anti-adherent effect on P. aeruginosa. Greater inhibition of adhesion was observed by excretions of non-irradiated lucilia sericata.

  10. Thermal History Using Microparticle Trap Luminescence

    Science.gov (United States)

    2012-06-01

    the size and shape of bacterial or viral agents and dispersed in a burst vessel . After the test, luminescence from the microparticles is measured to...platinum resistor sputtered on 1 nm adhesion layer of chrome, in turn on a 200nm LPCVD nitride; silicon wet -etching makes this a platform suspended...increased to 500°C until combustion occurred (- 7 min). The remaining powder was collected, crushed in a agate mortar, and annealed (typically at 900

  11. Biomimetic synthesis of selenium nanospheres by bacterial strain JS-11 and its role as a biosensor for nanotoxicity assessment: a novel se-bioassay.

    Science.gov (United States)

    Dwivedi, Sourabh; Alkhedhairy, Abdulaziz A; Ahamed, Maqusood; Musarrat, Javed

    2013-01-01

    Selenium nanoparticles (Se-NPs) were synthesized by green technology using the bacterial isolate Pseudomonas aeruginosa strain JS-11. The bacteria exhibited significant tolerance to selenite (SeO3(2-)) up to 100 mM concentration with an EC50 value of 140 mM. The spent medium (culture supernatant) contains the potential of reducing soluble and colorless SeO3(2-) to insoluble red elemental selenium (Se(0)) at 37°C. Characterization of red Se° product by use of UV-Vis spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM) with energy dispersive X-ray spectrum (EDX) analysis revealed the presence of stable, predominantly monodispersed and spherical selenium nanoparticles (Se-NPs) of an average size of 21 nm. Most likely, the metabolite phenazine-1-carboxylic acid (PCA) released by strain JS-11 in culture supernatant along with the known redox agents like NADH and NADH dependent reductases are responsible for biomimetic reduction of SeO3(2-) to Se° nanospheres. Based on the bioreduction of a colorless solution of SeO3(2-) to elemental red Se(0), a high throughput colorimetric bioassay (Se-Assay) was developed for parallel detection and quantification of nanoparticles (NPs) cytotoxicity in a 96 well format. Thus, it has been concluded that the reducing power of the culture supernatant of strain JS-11 could be effectively exploited for developing a simple and environmental friendly method of Se-NPs synthesis. The results elucidated that the red colored Se° nanospheres may serve as a biosensor for nanotoxicity assessment, contemplating the inhibition of SeO3(2-) bioreduction process in NPs treated bacterial cell culture supernatant, as a toxicity end point.

  12. Selection of potent bacterial strain for over-production of PHB by using low cost carbon source for eco-friendly bioplastics

    Directory of Open Access Journals (Sweden)

    Rahat Abdul Rehman

    2015-11-01

    Full Text Available Background: The microbial PHB production is a promising tool for the plastic industry for the synthesis of environmental friendly, biodegradable plastic in contrast to the conventional petro-chemical based non-degradable plastics. The selection of potent bacterial strains, inexpensive carbon source, efficient fermentation and recovery processes are important aspects that were taken into account during this study. Methods: Different bacterial strains i.e. Bacillus Spp, P. putida and P. fluorescens were screened for maximum PHB production. Under media optimization, various carbon and nitrogen sources (alone or in combination were used to achieve the maximum PHB production. Finally the degradation tests of the PHB sheet were also performed to test its biodegradability potential. Results: Shake flask studies have shown the PHB concentrations upto 7.02, 4.50 and 34.4 mg/g of dry cell mass of P. putida, P. fluorescens and Bacillus Spp. respectively. Almost same results were observed at laboratory scale production of PHB in 10 L fermenter i.e. 6.28, 6.23 and 39.5 mg/g of dry cell mass by P. putida, P. fluorescens and Bacillus Spp. respectively. On the basis of these observations, Bacillus Spp. was chosen for laboratory scale PHB production. Corn steep liquor (4% was chosen as the best medium to achieve the highest PHB contents. Isolated PHB has shown biodegradation in soil up to 86.7% at 37oC. Conclusion: The Bacillus Spp. Proved to be the best strain for PHB production on only 4% CSL which is cheapest and easily available.

  13. Identification of an Endophytic Antifungal Bacterial Strain Isolated from the Rubber Tree and Its Application in the Biological Control of Banana Fusarium Wilt.

    Directory of Open Access Journals (Sweden)

    Deguan Tan

    Full Text Available Banana Fusarium wilt (also known as Panama disease is one of the most disastrous plant diseases. Effective control methods are still under exploring. The endophytic bacterial strain ITBB B5-1 was isolated from the rubber tree, and identified as Serratia marcescens by morphological, biochemical, and phylogenetic analyses. This strain exhibited a high potential for biological control against the banana Fusarium disease. Visual agar plate assay showed that ITBB B5-1 restricted the mycelial growth of the pathogenic fungus Fusarium oxysporum f. sp. cubense race 4 (FOC4. Microscopic observation revealed that the cell wall of the FOC4 mycelium close to the co-cultured bacterium was partially decomposed, and the conidial formation was prohibited. The inhibition ratio of the culture fluid of ITBB B5-1 against the pathogenic fungus was 95.4% as estimated by tip culture assay. Chitinase and glucanase activity was detected in the culture fluid, and the highest activity was obtained at Day 2 and Day 3 of incubation for chitinase and glucanase, respectively. The filtrated cell-free culture fluid degraded the cell wall of FOC4 mycelium. These results indicated that chitinase and glucanase were involved in the antifungal mechanism of ITBB B5-1. The potted banana plants that were inoculated with ITBB B5-1 before infection with FOC4 showed 78.7% reduction in the disease severity index in the green house experiments. In the field trials, ITBB B5-1 showed a control effect of approximately 70.0% against the disease. Therefore, the endophytic bacterial strain ITBB B5-1 could be applied in the biological control of banana Fusarium wilt.

  14. Soil Type Dependent Rhizosphere Competence and Biocontrol of Two Bacterial Inoculant Strains and Their Effects on the Rhizosphere Microbial Community of Field-Grown Lettuce

    Science.gov (United States)

    Schreiter, Susanne; Sandmann, Martin; Smalla, Kornelia; Grosch, Rita

    2014-01-01

    Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 106 colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they significantly affected

  15. Soil type dependent rhizosphere competence and biocontrol of two bacterial inoculant strains and their effects on the rhizosphere microbial community of field-grown lettuce.

    Directory of Open Access Journals (Sweden)

    Susanne Schreiter

    Full Text Available Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 10(6 colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they

  16. Soil type dependent rhizosphere competence and biocontrol of two bacterial inoculant strains and their effects on the rhizosphere microbial community of field-grown lettuce.

    Science.gov (United States)

    Schreiter, Susanne; Sandmann, Martin; Smalla, Kornelia; Grosch, Rita

    2014-01-01

    Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 10(6) colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they significantly affected

  17. ISOLATION AND CHARACTERIZATION OF BIFENTHRIN CATABOLIZING BACTERIAL STRAIN BACILLUS CIBI FROM SOIL FOR PYRETHROIDS BIODEGRADATION

    OpenAIRE

    Preeti Pandey; Geetika Pant; G. Sibi

    2014-01-01

    Pyrethroids are commonly used in most parts of the world and are reported to have potential health risks. Bifenthrin, a third generation pyrethroid used as insecticide has caused potential effect on aquatic life and human health. Bioremediation is a practical approach to reduce pesticide in the environment and reports of microbial degradation of bifenthrin are meagre. This study was aimed at isolating and characterizing bacterial isolates for the efficient removal of bifenthrin residues in th...

  18. BACTERIAL CONSORTIUM

    Directory of Open Access Journals (Sweden)

    Payel Sarkar

    2013-01-01

    Full Text Available Petroleum aromatic hydrocarbons like benzen e, toluene, ethyl benzene and xylene, together known as BTEX, has almost the same chemical structure. These aromatic hydrocarbons are released as pollutants in th e environment. This work was taken up to develop a solvent tolerant bacterial cons ortium that could degrade BTEX compounds as they all share a common chemical structure. We have isolated almost 60 different types of bacterial strains from different petroleum contaminated sites. Of these 60 bacterial strains almost 20 microorganisms were screene d on the basis of capability to tolerate high concentration of BTEX. Ten differe nt consortia were prepared and the compatibility of the bacterial strains within the consortia was checked by gram staining and BTEX tolerance level. Four successful mi crobial consortia were selected in which all the bacterial strains concomitantly grew in presence of high concentration of BTEX (10% of toluene, 10% of benzene 5% ethyl benzene and 1% xylene. Consortium #2 showed the highest growth rate in pr esence of BTEX. Degradation of BTEX by consortium #2 was monitored for 5 days by gradual decrease in the volume of the solvents. The maximum reduction observed wa s 85% in 5 days. Gas chromatography results also reveal that could completely degrade benzene and ethyl benzene within 48 hours. Almost 90% degradation of toluene and xylene in 48 hours was exhibited by consortium #2. It could also tolerate and degrade many industrial solvents such as chloroform, DMSO, acetonitrile having a wide range of log P values (0.03–3.1. Degradation of aromatic hydrocarbon like BTEX by a solvent tolerant bacterial consortium is greatly significant as it could degrade high concentration of pollutants compared to a bacterium and also reduces the time span of degradation.

  19. Bacterial biodiversity analysis of a contaminated soil from the Chernobyl exclusion zone and characterization of the committed interaction of a Microbacterium strain with uranium

    International Nuclear Information System (INIS)

    Theodorakopoulos, Nicolas

    2013-01-01

    The nuclear power plants accidents of Chernobyl and Fukushima demonstrate the importance of the understanding of the transfer of the radioactive contamination in the environment and its ecological consequences. Although certain studies have been realized on superior organisms of the food chain, studies on telluric bacterial communities are scarce. The latter play nevertheless an essential role in the mobility of contaminants in soils by decreasing or improving their transfer towards other compartments (water, vegetables and animals). Moreover radionuclides (RNs) can have toxic effects on bacteria, leading to an inhibition of their participation in such transfer. The objectives of this study were (1) to estimate the impact of the radioactive contamination on bacterial communities belonging to a soil of the Chernobyl exclusion zone (trench T22) and (2) to study the uranium-bacteria interactions of a resistant strain, isolated from this soil. The various techniques used to characterize the bacterial diversity (culture of bacteria, DGGE, 454 pyro-sequencing) all testified of the multiplicity and the abundance of the bacterial communities in spite of the contamination. An impact on the community structure was difficult to assess by DGGE or cultural approach, but was nevertheless highlighted by the use of pyro-sequencing, suggesting the presence of species more adapted to the contaminated soil conditions. A specific molecular tool dedicated to the search of bacteria affiliated to the known radiation resistant Deinococcus-Thermus phylum (for example the Deinococcus radiodurans specie survives after an irradiation of several kGy) was developed. However it did not reveal the presence of bacteria affiliated to such a phylum in the studied soil. In parallel to the study of the bacterial biodiversity, about fifty culturable bacteria were isolated from this site and were used as a support to select a species (Microbacterium) capable to survive strong U(VI) concentrations. The

  20. Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source

    OpenAIRE

    Antoniou, Eleftheria; Fodelianakis, Stilianos; Korkakaki, Emmanouela; Kalogerakis, Nicolas

    2015-01-01

    Biosurfactants (BS) are green amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm biosurfactant producing strains or mixed consortia. The community structure of the best consortia based on the drop c...

  1. Isolation and Identification of an Indigenous Probiotic Lactobacillus Strain: Its Encapsulation with Natural Branched Polysaccharids to Improve Bacterial Viability

    OpenAIRE

    Nafiseh Sadat Foroutan; Fatemeh Tabandeh; Mahvash Khodabandeh; Naheed Mojgani; Amir Maghsoudi; Meisam Moradi

    2017-01-01

    Background and Objective: Probiotics have to reach their site of action in certain numbers in order to exhibit positive health effects. Encapsulation has shown remarkable enhancing effects on probiotic survival in simulated gastric conditions compared to free bacteria. The purpose of this study was identification and evaluation of a potential probiotic strain using encapsulation process by new carriers in order to improve probiotic viability during in vitro simulated conditions.Material and M...

  2. Isolation and Identification of an Indigenous Probiotic Lactobacillus Strain: Its Encapsulation with Natural Branched Polysaccharids to Improve Bacterial Viability

    Directory of Open Access Journals (Sweden)

    Nafiseh Sadat Foroutan

    2017-06-01

    Full Text Available Background and Objective: Probiotics have to reach their site of action in certain numbers in order to exhibit positive health effects. Encapsulation has shown remarkable enhancing effects on probiotic survival in simulated gastric conditions compared to free bacteria. The purpose of this study was identification and evaluation of a potential probiotic strain using encapsulation process by new carriers in order to improve probiotic viability during in vitro simulated conditions.Material and Methods: A native Lactobacillus was isolated from yogurt, identified as Lactobacillus casei PM01 (NCBI registered and analyzed for probiotic properties alongside established probiotic strains of Lactobacillus acidophilus ATCC 43556, and Lactobacillus rhamnosus ATCC 7469. Acid and bile resistance, adhesion to Caco-2 cells and antibiotic resistance were evaluated. Lactobacillus casei PM01 was encapsulated with alginate, chitosan and natural branched polysaccharides (pectin, tragacanth gum and gum Arabic by using extrusion technique. Encapsulation efficiency, acidification activity and viability of entrapped Lactobacillus casei PM01 in simulated gastric pH were determined. Results and Conclusion: Based on the results, all the three strains could be considered as potential probiotics, and are good candidates for further in vitro and in vivo evaluation. The results showed that the survival of encapsulated Lactobacillus casei PM01 was significantly (p≤0.05 increased when it was incubated in simulated gastric pH. It can be concluded that indigenous Lactobacillus casei PM01 in encapsulated form is introduced as an efficient probiotic strain for using in dairy products.Conflict of interest: The authors declare no conflict of interest.

  3. Effect of Different Carbon Sources on Bacterial Nanocellulose Production and Structure Using the Low pH Resistant Strain Komagataeibacter Medellinensis

    Directory of Open Access Journals (Sweden)

    Carlos Molina-Ramírez

    2017-06-01

    Full Text Available Bacterial cellulose (BC is a polymer obtained by fermentation with microorganism of different genera. Recently, new producer species have been discovered, which require identification of the most important variables affecting cellulose production. In this work, the influence of different carbon sources in BC production by a novel low pH-resistant strain Komagataeibacter medellinensis was established. The Hestrin-Schramm culture medium was used as a reference and was compared to other media comprising glucose, fructose, and sucrose, used as carbon sources at three concentrations (1, 2, and 3% w/v. The BC yield and dynamics of carbon consumption were determined at given fermentation times during cellulose production. While the carbon source did not influence the BC structural characteristics, different production levels were determined: glucose > sucrose > fructose. These results highlight considerations to improve BC industrial production and to establish the BC property space for applications in different fields.

  4. Indigenous Pseudomonas spp. Strains from the Olive (Olea europaea L.) Rhizosphere as Effective Biocontrol Agents against Verticillium dahliae: From the Host Roots to the Bacterial Genomes

    Science.gov (United States)

    Gómez-Lama Cabanás, Carmen; Legarda, Garikoitz; Ruano-Rosa, David; Pizarro-Tobías, Paloma; Valverde-Corredor, Antonio; Niqui, José L.; Triviño, Juan C.; Roca, Amalia; Mercado-Blanco, Jesús

    2018-01-01

    The use of biological control agents (BCA), alone or in combination with other management measures, has gained attention over the past decades, driven by the need to seek for sustainable and eco-friendly alternatives to confront plant pathogens. The rhizosphere of olive (Olea europaea L.) plants is a source of bacteria with potential as biocontrol tools against Verticillium wilt of olive (VWO) caused by Verticillium dahliae Kleb. A collection of bacterial isolates from healthy nursery-produced olive (cultivar Picual, susceptible to VWO) plants was generated based on morphological, biochemical and metabolic characteristics, chemical sensitivities, and on their in vitro antagonistic activity against several olive pathogens. Three strains (PIC25, PIC105, and PICF141) showing high in vitro inhibition ability of pathogens' growth, particularly against V. dahliae, were eventually selected. Their effectiveness against VWO caused by the defoliating pathotype of V. dahliae was also demonstrated, strain PICF141 being the rhizobacteria showing the best performance as BCA. Genotypic and phenotypic traits traditionally associated with plant growth promotion and/or biocontrol abilities were evaluated as well (e.g., phytase, xylanase, catalase, cellulase, chitinase, glucanase activities, and siderophore and HCN production). Multi-locus sequence analyses of conserved genes enabled the identification of these strains as Pseudomonas spp. Strain PICF141 was affiliated to the “Pseudomonas mandelii subgroup,” within the “Pseudomonas fluorescens group,” Pseudomonas lini being the closest species. Strains PIC25 and PIC105 were affiliated to the “Pseudomonas aeruginosa group,” Pseudomonas indica being the closest relative. Moreover, we identified P. indica (PIC105) for the first time as a BCA. Genome sequencing and in silico analyses allowed the identification of traits commonly associated with plant-bacteria interactions. Finally, the root colonization ability of these olive

  5. The Effect of Specific Conditions on Cu, Ni, Zn and Al Recovery from PCBS Waste Using Acidophilic Bacterial Strains

    Directory of Open Access Journals (Sweden)

    Mrážiková A.

    2016-03-01

    Full Text Available The objective of this work was to evaluate the influence of static, stirring and shaking conditions on copper, zinc, nickel and aluminium dissolution from printed circuit boards (PCBs using the mixed acidophilic bacterial culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The results revealed that static conditions were the most effective in zinc and aluminium dissolution. Zinc was removed almost completely under static conditions, whereas maximum of nickel dissolution was reached under the stirring conditions. The highest copper recovery (36% was reached under stirring conditions. The shaking conditions appeared to be the least suitable. The relative importance of these systems for the bioleaching of copper and nickel decreased in the order: stirring, static conditions, shaking.

  6. Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source

    Directory of Open Access Journals (Sweden)

    Eleftheria eAntoniou

    2015-04-01

    Full Text Available Biosurfactants (BS are green amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm biosurfactant producing strains or mixed consortia. The community structure of the best consortia based on the drop collapse test was determined by 16S-rDNA pyrotag screening. Subsequently, the effect of incubation time, temperature, substrate and supplementation with inorganic nutrients, on biosurfactant production, was examined. Two types of BS - lipid mixtures were extracted from the culture broth; the low molecular weight BS Rhamnolipids and Sophorolipids. Crude extracts were purified by silica gel column chromatography and then identified by thin layer chromatography (TLC and Fourier transform infrared spectroscopy (FT-IR. Results indicate that biosurfactant production yield remains constant and low while it is independent of the total culture biomass, carbon source, and temperature. A constant BS concentration in a culture broth with continuous degradation of crude oil implies that the BS producing microbes generate no more than the required amount of biosurfactants that enables biodegradation of the crude oil. Isolated pure strains were found to have higher specific production yields than the complex microbial marine community-consortia. The heavy oil fraction of crude oil has emerged as a promising substrate for BS production (by marine BS producers with fewer impurities in the final product. Furthermore, a particular strain isolated from sediments, Paracoccus marcusii, may be an optimal choice for bioremediation purposes as its biomass remains trapped in the hydrocarbon phase, not suffering from potential dilution effects by sea currents.

  7. Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source.

    Science.gov (United States)

    Antoniou, Eleftheria; Fodelianakis, Stilianos; Korkakaki, Emmanouela; Kalogerakis, Nicolas

    2015-01-01

    Biosurfactants (BSs) are "green" amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm BS producing strains or mixed consortia. The community structure of the best consortia based on the drop collapse test was determined by 16S-rDNA pyrotag screening. Subsequently, the effect of incubation time, temperature, substrate and supplementation with inorganic nutrients, on BS production, was examined. Two types of BS - lipid mixtures were extracted from the culture broth; the low molecular weight BS Rhamnolipids and Sophorolipids. Crude extracts were purified by silica gel column chromatography and then identified by thin layer chromatography and Fourier transform infrared spectroscopy. Results indicate that BS production yield remains constant and low while it is independent of the total culture biomass, carbon source, and temperature. A constant BS concentration in a culture broth with continuous degradation of crude oil (CO) implies that the BS producing microbes generate no more than the required amount of BSs that enables biodegradation of the CO. Isolated pure strains were found to have higher specific production yields than the complex microbial marine community-consortia. The heavy oil fraction of CO has emerged as a promising substrate for BS production (by marine BS producers) with fewer impurities in the final product. Furthermore, a particular strain isolated from sediments, Paracoccus marcusii, may be an optimal choice for bioremediation purposes as its biomass remains trapped in the hydrocarbon phase, not suffering from potential dilution effects by sea currents.

  8. Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source

    Science.gov (United States)

    Antoniou, Eleftheria; Fodelianakis, Stilianos; Korkakaki, Emmanouela; Kalogerakis, Nicolas

    2015-01-01

    Biosurfactants (BSs) are “green” amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm BS producing strains or mixed consortia. The community structure of the best consortia based on the drop collapse test was determined by 16S-rDNA pyrotag screening. Subsequently, the effect of incubation time, temperature, substrate and supplementation with inorganic nutrients, on BS production, was examined. Two types of BS – lipid mixtures were extracted from the culture broth; the low molecular weight BS Rhamnolipids and Sophorolipids. Crude extracts were purified by silica gel column chromatography and then identified by thin layer chromatography and Fourier transform infrared spectroscopy. Results indicate that BS production yield remains constant and low while it is independent of the total culture biomass, carbon source, and temperature. A constant BS concentration in a culture broth with continuous degradation of crude oil (CO) implies that the BS producing microbes generate no more than the required amount of BSs that enables biodegradation of the CO. Isolated pure strains were found to have higher specific production yields than the complex microbial marine community-consortia. The heavy oil fraction of CO has emerged as a promising substrate for BS production (by marine BS producers) with fewer impurities in the final product. Furthermore, a particular strain isolated from sediments, Paracoccus marcusii, may be an optimal choice for bioremediation purposes as its biomass remains trapped in the hydrocarbon phase, not suffering from potential dilution effects by sea currents. PMID:25904907

  9. Positron-Induced Luminescence

    Science.gov (United States)

    Stenson, E. V.; Hergenhahn, U.; Stoneking, M. R.; Pedersen, T. Sunn

    2018-04-01

    We report on the observation that low-energy positrons incident on a phosphor screen produce significantly more luminescence than electrons do. For two different wide-band-gap semiconductor phosphors (ZnS:Ag and ZnO:Zn), we compare the luminescent response to a positron beam with the response to an electron beam. For both phosphors, the positron response is significantly brighter than the electron response, by a factor that depends strongly on incident energy (0-5 keV). Positrons with just a few tens of electron-volts of energy (for ZnS:Ag) or less (for ZnO:Zn) produce as much luminescence as is produced by electrons with several kilo-electron-volts. We attribute this effect to valence band holes and excited electrons produced by positron annihilation and subsequent Auger processes. These results demonstrate a valuable approach for addressing long-standing questions about luminescent materials.

  10. Purification and characterization of enterocin 62-6, a two-peptide bacteriocin produced by a vaginal strain of Enterococcus faecium: Potential significance in bacterial vaginosis

    Science.gov (United States)

    Dezwaan, Diane C.; Mequio, Michael J.; Littell, Julia S.; Allen, Jonathan P.; Rossbach, Silvia; Pybus, Vivien

    2009-01-01

    A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designated enterocin 62-6, was characterized following purification and DNA sequence analysis and compared to previously described bacteriocins. Enterocin 62-6 was isolated from brain heart infusion (BHI) culture supernatants using ammonium sulfate precipitation followed by elution from a Sepharose cation exchange column using a continuous salt gradient (0.1–0.7 M NaCl). SDS-PAGE of an active column fraction resulted in an electrophoretically pure protein, which corresponded to the growth inhibition of the sensitive Lactobacillus indicator strain in the gel overlay assay. Purified enterocin 62-6 was shown to be heat- and pH-stable, and sensitive to the proteolytic enzymes α-chymotrypsin and pepsin. Results from mass spectrometry suggested that it comprised two peptides of 5206 and 5219±1 Da, which was confirmed by DNA sequence analysis. The characteristics of enterocin 62-6 as a small, heat- and pH-stable, cationic, hydrophobic, two-peptide, plasmid-borne bacteriocin, with an inhibitory spectrum against a broad range of Gram-positive but not Gram-negative bacteria, were consistent with its classification as a class IIc bacteriocin. Furthermore, its wide spectrum of growth inhibitory activity against Gram-positive bacteria of vaginal origin including lactobacilli, and stability under the acidic conditions of the vagina, are consistent with our hypothesis that it could have potential significance in disrupting the ecology of the vaginal tract and pave the way for the establishment of the abnormal microbiota associated with the vaginal syndrome bacterial vaginosis. This is the first class IIc bacteriocin produced by a strain of E. faecium of vaginal origin to be characterized. PMID:19578555

  11. A novel approach to eliminate Wolbachia infections in Nasonia vitripennis revealed different antibiotic resistance between two bacterial strains.

    Science.gov (United States)

    Liu, Hai-Yang; Wang, Yan-Kun; Zhi, Cong-Cong; Xiao, Jin-Hua; Huang, Da-Wei

    2014-06-01

    Wolbachia are widespread in insects and can manipulate host reproduction. Nasonia vitripennis is a widely studied organism with a very high prevalence of Wolbachia infection. To study the effect of Wolbachia infection in Nasonia spp., it is important to obtain noninfected individuals by artificial methods. Current methods that employ sugar water-containing antibiotics can successfully eliminate Wolbachia from the parasitic wasps; however, treatment of at least three generations is required. Here, we describe a novel, feasible, and effective approach to eliminate Wolbachia from N. vitripennis by feeding fly pupae continuously offering antibiotics to Nasonia populations, which shortened the time to eliminate the pathogens to two generations. Additionally, the Wolbachia Uni and CauB strains have obviously different rifampicin-resistance abilities, which is a previously unknown phenomenon. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  12. Stress determination in thermally grown alumina scales using ruby luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Renusch, D.; Veal, B.W.; Koshelev, I.; Natesan, K.; Grimsditch [Argonne National Lab., IL (United States); Hou, P.Y. [Lawrence Berkeley Lab., CA (United States)

    1996-06-01

    By exploiting the strain dependence of the ruby luminescence line, we have measured the strain in alumina scales thermally grown on Fe-Cr- Al alloys. Results are compared and found to be reasonably consistent with strains determined using x rays. Oxidation studies were carried out on alloys Fe - 5Cr - 28Al and Fe - 18Cr - 10Al (at.%). Significantly different levels of strain buildup were observed in scales on these alloys. Results on similar alloys containing a ``reactive element`` (Zr or Hf) in dilute quantity are also presented. Scales on alloys containing a reactive element (RE) can support significantly higher strains than scales on RE-free alloys. With the luminescence technique, strain relief associated with spallation thresholds is readily observed.

  13. Biosynthesis of myristic acid in luminescent bacteria

    International Nuclear Information System (INIS)

    Byers, D.M.

    1987-01-01

    In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with [ 14 C] acetate in a nutrient-depleted medium accumulated substantial tree [ 14 C]fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with [ 14 C]acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition

  14. Isolation of a bacterial strain, Acinetobacter sp. from centrate wastewater and study of its cooperation with algae in nutrients removal.

    Science.gov (United States)

    Liu, Hui; Lu, Qian; Wang, Qin; Liu, Wen; Wei, Qian; Ren, Hongyan; Ming, Caibing; Min, Min; Chen, Paul; Ruan, Roger

    2017-07-01

    Algae were able to grow healthy on bacteria-containing centrate wastewater in a pilot-scale bioreactor. The batch experiment indicated that the co-cultivation of algae and wastewater-borne bacteria improved the removal efficiencies of chemical oxygen demand and total phosphorus in centrate wastewater to 93.01% and 98.78%, respectively. A strain of beneficial aerobic bacteria, Acinetobacter sp., was isolated and its biochemical characteristics were explored. Synergistic cooperation was observed in the growth of algae and Acinetobacter sp. Removal efficiencies of some nutrients were improved significantly by the co-cultivation of algae and Acinetobacter sp. After treatment, residual nutrients in centrate wastewater reached the permissible discharge limit. The cooperation between algae and Acinetobacter sp. was in part attributed to the exchange of carbon dioxide and oxygen between the algae and bacteria. This synergetic relationship between algae and Acinetobacter sp. provided a promising way to treat the wastewater by improving the nutrients removal and biomass production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Different flour microbial communities drive to sourdoughs characterized by diverse bacterial strains and free amino acid profiles

    Directory of Open Access Journals (Sweden)

    GIUSEPPE CELANO

    2016-11-01

    Full Text Available This work aimed to investigate whether different microbial assemblies in flour may influence the microbiological and biochemical characteristics of traditional sourdough. To reach this purpose, members of lactic acid bacteria, enterobacteria, and yeasts were isolated from durum wheat flour. Secondly, the isolated microorganisms (Pediococcus pentosaceus, Saccharomyces cerevisiae, Pantoea agglomerans, and Escherichia hermanni were inoculated in doughs prepared with irradiated flour (gamma rays at 10 kGy, so that eight different microbial assemblies were obtained. Two non-inoculated controls were prepared, one of which (C-IF using irradiated flour and the other (C using non-irradiated flour.As shown by plate counts, irradiation of flour caused total inactivation of yeasts and a decrease of all the other microbial populations. However acidification occurred also in the dough C-IF, due to metabolic activity of P. pentosaceus that had survived irradiation. After six fermentations, P. pentosaceus was the dominant lactic acid bacterium species in all the sourdoughs produced with irradiated flour (IF. Yet, IF-based sourdoughs broadly differed from each other in terms of strains of P. pentosaceus, probably due to the different microorganisms initially inoculated. Quantitative and qualitative differences of free amino acids concentration were found among the sourdoughs, possibly because of different microbial communities. In addition, as shown by culture-independent analysis (16S metagenetics, irradiation of flour lowered and modified microbial diversity of sourdough ecosystem.

  16. Effect of feeding tannin degrading bacterial culture (Streptococcus gallolyticus strain TDGB 406) on nutrient utilization, urinary purine derivatives and growth performance of goats fed on Quercus semicarpifolia leaves.

    Science.gov (United States)

    Kumar, K; Chaudhary, L C; Agarwal, N; Kamra, D N

    2014-10-01

    To study the effect of supplementation of tannin degrading bacterial culture (Streptococcus gallolyticus strain TDGB 406) on growth performance, nutrient utilization and urinary purine derivatives of goats fed on oak (Quercus semicarpifolia) leaves. For growth study, eighteen billy goats (4 month old, average body weight 9.50 ± 1.50 kg) were distributed into three groups of six animals each. The animals of group 1 served as control while animals of groups 2 (T1) and 3 (T2) were given (@ 5 ml/kg live weight) autoclaved and live culture of isolate TDGB 406 (10(6) cells/ml) respectively. The animals were fed measured quantity of dry oak leaves as the main roughage source and ad libitum maize hay along with fixed quantity of concentrate mixture. The feeding of live culture of isolate TDGB 406 (probiotic) did not affect dry matter intake and digestibility of nutrients except that of dry matter and crude protein, which was higher in T2 group as compared to control. All the animals were in positive nitrogen balance. There was no significant effect of feeding isolate TDGB 406 on urinary purine derivatives (microbial protein production) in goats. The body weight gain and average live weight gain was significantly higher (p = 0.071) in T2 group as compared to control. Feed conversion efficiency was also better in the goats fed on live culture of TDGB 406 (T2). The feeding of tannin degrading bacterial isolate TDGB 406 as probiotic resulted in improved growth performance and feed conversion ratio in goats fed on oak leaves as one of the main roughage source. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

  17. Involvement of hrpX and hrpG in the Virulence of Acidovorax citrulli Strain Aac5, Causal Agent of Bacterial Fruit Blotch in Cucurbits

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Zhang

    2018-03-01

    Full Text Available Acidovorax citrulli causes bacterial fruit blotch, a disease that poses a global threat to watermelon and melon production. Despite its economic importance, relatively little is known about the molecular mechanisms of pathogenicity and virulence of A. citrulli. Like other plant-pathogenic bacteria, A. citrulli relies on a type III secretion system (T3SS for pathogenicity. On the basis of sequence and operon arrangement analyses, A. citrulli was found to have a class II hrp gene cluster similar to those of Xanthomonas and Ralstonia spp. In the class II hrp cluster, hrpG and hrpX play key roles in the regulation of T3SS effectors. However, little is known about the regulation of the T3SS in A. citrulli. This study aimed to investigate the roles of hrpG and hrpX in A. citrulli pathogenicity. We found that hrpG or hrpX deletion mutants of the A. citrulli group II strain Aac5 had reduced pathogenicity on watermelon seedlings, failed to induce a hypersensitive response in tobacco, and elicited higher levels of reactive oxygen species in Nicotiana benthamiana than the wild-type strain. Additionally, we demonstrated that HrpG activates HrpX in A. citrulli. Moreover, transcription and translation of the type 3-secreted effector (T3E gene Aac5_2166 were suppressed in hrpG and hrpX mutants. Notably, hrpG and hrpX appeared to modulate biofilm formation. These results suggest that hrpG and hrpX are essential for pathogenicity, regulation of T3Es, and biofilm formation in A. citrulli.

  18. Mercury (II) removal by resistant bacterial isolates and mercuric (II) reductase activity in a new strain of Pseudomonas sp. B50A.

    Science.gov (United States)

    Giovanella, Patricia; Cabral, Lucélia; Bento, Fátima Menezes; Gianello, Clesio; Camargo, Flávio Anastácio Oliveira

    2016-01-25

    This study aimed to isolate mercury resistant bacteria, determine the minimum inhibitory concentration for Hg, estimate mercury removal by selected isolates, explore the mer genes, and detect and characterize the activity of the enzyme mercuric (II) reductase produced by a new strain of Pseudomonas sp. B50A. The Hg removal capacity of the isolates was determined by incubating the isolates in Luria Bertani broth and the remaining mercury quantified by atomic absorption spectrophotometry. A PCR reaction was carried out to detect the merA gene and the mercury (II) reductase activity was determined in a spectrophotometer at 340 nm. Eight Gram-negative bacterial isolates were resistant to high mercury concentrations and capable of removing mercury, and of these, five were positive for the gene merA. The isolate Pseudomonas sp. B50A removed 86% of the mercury present in the culture medium and was chosen for further analysis of its enzyme activity. Mercuric (II) reductase activity was detected in the crude extract of this strain. This enzyme showed optimal activity at pH 8 and at temperatures between 37 °C and 45 °C. The ions NH4(+), Ba(2+), Sn(2+), Ni(2+) and Cd(2+) neither inhibited nor stimulated the enzyme activity but it decreased in the presence of the ions Ca(2+), Cu(+) and K(+). The isolate and the enzyme detected were effective in reducing Hg(II) to Hg(0), showing the potential to develop bioremediation technologies and processes to clean-up the environment and waste contaminated with mercury. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Direct bacterial loop-mediated isothermal amplification detection on the pathogenic features of the nosocomial pathogen - Methicillin resistant Staphylococcus aureus strains with respiratory origins.

    Science.gov (United States)

    Lin, Qun; Xu, Pusheng; Li, Jiaowu; Chen, Yin; Feng, Jieyi

    2017-08-01

    Loop-mediated isothermal amplification based detection assays using bacterial culture or colony for direct detection of methicillin resistant Staphylococcus aureus(MRSA) had been developed and evaluated, followed by its extensive application on a large scale of clinical MRSA isolated from respiratory origins, including nasal swabs and sputums. Six primers, including outer primers, inner primers and loop primers, were specifically designed for recognizing eight distinct sequences on four targets: 16SrRNA, femA, mecA and orfX. Twenty-seven reference strains were used to develop, evaluate and optimize this assay. Then, a total of 532 clinical MRSA isolates were employed for each detected targets. And the results were determined through both visual observation of the color change by naked eye and electrophoresis. The specific of each primer had been confirmed, and the optimal amplification was obtained under 65 °C for 40 min. The limit of detections (LOD) of bacteria culture LAMP assays were determined to be 10 4  CFU/ml for 16S rRNA, femA, as well as orfX and 10 5  CFU/ml for mecA, respectively. The established novel assays on MRSA detection may provide new strategies for rapid detection of foodborne pathogens. Copyright © 2017. Published by Elsevier Ltd.

  20. A Simple Luminescent Adenylate-Cyclase Functional Assay for Evaluation of Bacillus anthracis Edema Factor Activity

    Directory of Open Access Journals (Sweden)

    Ma’ayan Israeli

    2016-08-01

    Full Text Available Edema Factor (EF, the toxic sub-unit of the Bacillus anthracis Edema Toxin (ET is a calmodulin-dependent adenylate cyclase whose detrimental activity in the infected host results in severe edema. EF is therefore a major virulence factor of B. anthracis. We describe a simple, rapid and reliable functional adenylate-cyclase assay based on inhibition of a luciferase-mediated luminescence reaction. The assay exploits the efficient adenylate cyclase-mediated depletion of adenosine tri-phosphate (ATP, and the strict dependence on ATP of the light-emitting luciferase-catalyzed luciferin-conversion to oxyluciferin, which can be easily visualized. The assay exhibits a robust EF-dose response decrease in luminescence, which may be specifically reverted by anti-EF antibodies. The application of the assay is exemplified in: (a determining the presence of EF in B. anthracis cultures, or its absence in cultures of EF-defective strains; (b evaluating the anti-EF humoral response in experimental animals infected/vaccinated with B. anthracis; and (c rapid discrimination between EF producing and non-producing bacterial colonies. Furthermore, the assay may be amenable with high-throughput screening for EF inhibitory molecules.

  1. Novel Accurate Bacterial Discrimination by MALDI-Time-of-Flight MS Based on Ribosomal Proteins Coding in S10-spc-alpha Operon at Strain Level S10-GERMS

    Science.gov (United States)

    Tamura, Hiroto; Hotta, Yudai; Sato, Hiroaki

    2013-08-01

    Matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is one of the most widely used mass-based approaches for bacterial identification and classification because of the simple sample preparation and extremely rapid analysis within a few minutes. To establish the accurate MALDI-TOF MS bacterial discrimination method at strain level, the ribosomal subunit proteins coded in the S 10-spc-alpha operon, which encodes half of the ribosomal subunit protein and is highly conserved in eubacterial genomes, were selected as reliable biomarkers. This method, named the S10-GERMS method, revealed that the strains of genus Pseudomonas were successfully identified and discriminated at species and strain levels, respectively; therefore, the S10-GERMS method was further applied to discriminate the pathovar of P. syringae. The eight selected biomarkers (L24, L30, S10, S12, S14, S16, S17, and S19) suggested the rapid discrimination of P. syringae at the strain (pathovar) level. The S10-GERMS method appears to be a powerful tool for rapid and reliable bacterial discrimination and successful phylogenetic characterization. In this article, an overview of the utilization of results from the S10-GERMS method is presented, highlighting the characterization of the Lactobacillus casei group and discrimination of the bacteria of genera Bacillus and Sphingopyxis despite only two and one base difference in the 16S rRNA gene sequence, respectively.

  2. Luminescence study of spodumene

    International Nuclear Information System (INIS)

    Isotani, S.; Fujii, A.T.; Antonini, R.; Pontuschka, W.M.; Rabani, S.R.; Furtado, W.W.

    1990-02-01

    A comparative study is made of the luminescence of five kinds of spodumene from Minas Gerais, Brazil, studied previously by optical absorption spectroscopy. Natural gemstones are used which, in the course of the experiments, were irradiated with X-rays. (L.C.) [pt

  3. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  4. Antibiotic sensitivity of bacterial strains isolated from newborn infants Sensibilidad a los antibióticos de bacterias aisladas de neonatos hospitalizados

    Directory of Open Access Journals (Sweden)

    Alvaro Uribe

    1990-02-01

    Full Text Available

    Eighty nine bacterial strains isolated from newborn infants hospitalized at a Special Care Unit in Medellin, Colombia, were studied. The sensitivity of each one was determined by the Minimallnhibitory Concentration method against 21 antibiotics; a high frequency of resistance was found toward gentamycin, netilmycin, oxacillin, penicillin G and ampicillin, that are often employed as initial therapy in newborn infants; on the other hand both Gram positive and Gram negative bacteria exhibited high percentages of sensitivity against quinolones; aztreonam and third generation cephalosporins were also highly effective against Gram negative bacilli. On the basis of this new information the need to restate therapeutic conducts in the case of serious bacterial neonatal infections is emphasized.

    Se estudiaron 89 cepas bacterianas aisladas de neonatos hospitalizados en la sala de cuidados especiales de la Fundación Hospitalaria San Vicente de Paúl, de Medellín; a cada una se le determinó la sensibilidad frente a 21 antibióticos por el método de la concentración inhibitoria mínima (CIM; se halló una alta frecuencia de resistencia hacia la gentamicina, la netilmicina, la oxacilina y la ampicilina que se usan a menudo en esta institución como terapia inicial en las infecciones del recién nacido; por otra parte se demostraron altos porcentajes de sensibilidad hacia las quinolonas tanto de las bacterias gram positivas como de las gram negativas; contra estas últimas también fueron muy efectivos el aztreonam y las cefalosporinas de tercera generación. A la luz de esta nueva información se llama la atención hacia la necesidad de revaluar las normas de la antibioterapia en las infecciones graves del recién nacido.

  5. Effectiveness of Origanum vulgare L. and Origanum majorana L. essential oils in inhibiting the growth of bacterial strains isolated from the patients with conjunctivitis

    Directory of Open Access Journals (Sweden)

    Jana Luíza Toscano Mendes de Oliveira

    2009-02-01

    Full Text Available This study aimed to evaluate the antibacterial activity of Origanum vulgare L. and O. majorana L. essential oils on Staphylococcus aureus, S. coagulase negative, Enterobacter spp., Proteus spp., Acinetobacter spp., Klebsiella spp. isolated from the patients with conjunctivitis. The results showed a prominent inhibitory effect of both the essential oils on all the bacterial strains, noted by the large bacterial growth inhibition zones (15-32mm. The Minimum Inhibitory Concentrations (MIC values were between 5-20µL/mL and 2.5-10 µL/mL for O. vulgare and O. majorana essential oil, respectively. The MIC were able to cause significant (PEste estudo objetivou analisar a atividade antibacteriana do óleo essencial de O. vulgare L. and O. majorana L. sobre cepas bacterianas (Staphylococcus aureus, S. coagulase negative, Enterobacter spp., Proteus spp., Acinetobacter spp., Klebsiella spp. isoladas de pacientes com conjuntivite. Os resultados mostraram um destacável efeito inibitório de ambos os óleos essenciais ensaiadossobre todas as cepas bacterianas, notado pela formação de amplas zonas de inibição do crescimento bacteriano (15-32 mm. Os valores de Concentração Inibitória Mínima - CIM encontradas estiveram entre 5-20µL/mL e 2.5-10 µL/mL para o óleo essencial de O. vulgare e O. majorana, respectivamente. Os valores de CIM foram capazes de causar significante efeito inibitório sobre a viabilidade celular de Klebisiella spp., Proteus spp. e S. aureus causando uma total eliminação do inóculo microbiano em um tempo máximo de 24 h de exposição. Estes resultados mostraram a efetividade antibacteriana dos óleos essenciais de O. vulgare e O. majorana, bem como suporta a possibilidade do uso de tais produtos como fontes de compostos antimicrobianos.

  6. Experimental infection with different bacterial strains in larvae and juvenile Litopenaeus vannamei reared in Santa Catarina State, Brazil - doi: 10.4025/actascibiolsci.v32i3.5471

    OpenAIRE

    Buglione, Celso Carlos; UFSC; Vieira, Felipe do Nascimento; UFSC; Mouriño, José Luiz Pedreira; UFSC; Pedrotti, Fabiola Santiago; UFSC; Jatoba, Adolfo; UFSC; Martins, Maurício Laterça; UFSC

    2010-01-01

    This study evaluated the pathogenic characteristics of bacteria isolated from Litopenaeus vannamei during an outbreak at the Laboratory of Marine Shrimp, UFSC, Santa Catarina State, Brazil. Their virulence potential in larvae and juvenile shrimp and the effects on the total haemocyte count, phenoloxidase activity and serum agglutinate titre were examined after experimental infection. Bacterial strains were isolated from larvae and adult shrimps, identified by the AP120E biochemical system as:...

  7. Construction of a Recombinant Allergen-Producing Probiotic Bacterial Strain: Introduction of a New Line for a Live Oral Vaccine Against Chenopodium album Pollen Allergy

    Directory of Open Access Journals (Sweden)

    Leila Roozbeh Nasiraie

    2013-10-01

    Full Text Available Background: During the last two decades, significant advances have been made in the fields of lactococcal genetics and protein expression. Lactococcus lactis (L. lactis is an effective vector for protein expression and can be used as an antigen delivery system. Hence, L. lactis is an ideal candidate for mucosal immunotherapy. Profilin (Che a 2, the major allergen in Chenopodium album, is one of the most important causes of allergic diseases in desert and semi-desert areas, especially in Iran, Saudi Arabia, and Kuwait that was cloned and expressed in L. lactis for the first time. Methods: To construct L. lactis that expressed Che a 2, a DNA sequence was cloned and used to transform bacteria. Expression of Che a 2 was analyzed via monitoring of related RNA and protein. Hydrophobicity, adherence to HT-29 cells, antibiotic resistance, resistance to gastrointestinal contents, pH, and bile salt in recombinant and native L. lactis were evaluated. Results: Immunoblot analyses demonstrated that recombinant Che a 2 is expressed as a 32 kDa dimeric protein immunological studies showed it can bind human IgE. Both native and recombinant bacteria were sensitive to low pH and simulated gastric conditions. Bacterial survival was reduced 80-100% after 2 h of exposure to pH 1.5-2. Both native and recombinant bacteria were able to grow in 0.3 and 2% bile salts. After incubation of recombinant L. lactis in simulated gastric and intestinal juices for one and two hours, respectively, cell survival was reduced by 100%. Adhesion capability in both strains was minimal and there were no significant differences in any of our tests between native and recombinant bacteria. Conclusion: Successfully recombinant L. lactis with capability of expression Che a 2 was produced and revealed it is sensitive to gastrointestinal contents.

  8. Proof of Principle for a Real-Time Pathogen Isolation Media Diagnostic: The Use of Laser-Induced Breakdown Spectroscopy to Discriminate Bacterial Pathogens and Antimicrobial-Resistant Staphylococcus aureus Strains Grown on Blood Agar

    Directory of Open Access Journals (Sweden)

    Rosalie A. Multari

    2013-01-01

    Full Text Available Laser-Induced Breakdown Spectroscopy (LIBS is a rapid, in situ, diagnostic technique in which light emissions from a laser plasma formed on the sample are used for analysis allowing automated analysis results to be available in seconds to minutes. This speed of analysis coupled with little or no sample preparation makes LIBS an attractive detection tool. In this study, it is demonstrated that LIBS can be utilized to discriminate both the bacterial species and strains of bacterial colonies grown on blood agar. A discrimination algorithm was created based on multivariate regression analysis of spectral data. The algorithm was deployed on a simulated LIBS instrument system to demonstrate discrimination capability using 6 species. Genetically altered Staphylococcus aureus strains grown on BA, including isogenic sets that differed only by the acquisition of mutations that increase fusidic acid or vancomycin resistance, were also discriminated. The algorithm successfully identified all thirteen cultures used in this study in a time period of 2 minutes. This work provides proof of principle for a LIBS instrumentation system that could be developed for the rapid discrimination of bacterial species and strains demonstrating relatively minor genomic alterations using data collected directly from pathogen isolation media.

  9. Luminescence, virulence and quorum sensing signal production by pathogenic Vibrio campbellii and Vibrio harveyi isolates

    OpenAIRE

    Defoirdt, T.; Verstraete, W.; Bossier, P.

    2008-01-01

    Aims: To study the relationship between luminescence, autoinducer production and virulence of pathogenic vibrios.Methods and Results: Luminescence, quorum sensing signal production and virulence towards brine shrimp nauplii of 13 Vibrio campbellii and Vibrio harveyi strains were studied. Although only two of the tested strains were brightly luminescent, all of them were shown to produce the three different types of quorum sensing signals known to be produced by Vibrio harveyi. Cell-free cultu...

  10. Luminescent solar concentrator

    Directory of Open Access Journals (Sweden)

    Tugce Tosun

    2015-07-01

    Full Text Available Luminescent solar concentrator (LSC is a device that has luminescent molecules embedding or topping polymeric or glass waveguide to generate electricity from sunlight with a photovoltaic cell attachment. LSCs can be employed both in small and large scale projects, independent on the direction or angle of the surface with respect to the sun, promising more freedom for integration in urban environments compared to the traditional PV systems. The aim of the SEB&C PDEng project is to investigate the applicability of this innovative technology in the built environment and to bridge the gap of knowledge linking societal, design and technological aspects. The final goal is to exhibit potential application concepts of LSC developed by co-creative methods at SPARK campus which is a hub for open innovation in built environment. Necessity of a paradigm shift towards sustainable and smart cities came into being due to the significant increase in energy demand of the buildings. The challenge is to increase renewable sources in the energy mix while designing aesthetic environments. Thus, building integrated renewable energy technologies represent a great opportunity to help overcome this current challenge. Smart energy, energy efficiency and use of renewable sources are key aspects to be considered nowadays and many innovative technologies need further exploitation to be commercially viable, such as luminescent solar concentrator.

  11. Quantitative luminescence imaging system

    Science.gov (United States)

    Erwin, David N.; Kiel, Johnathan L.; Batishko, Charles R.; Stahl, Kurt A.

    1990-01-01

    The QLIS images and quantifies low-level chemiluminescent reactions in an electromagnetic field. It is capable of real time nonperturbing measurement and simultaneous recording of many biochemical and chemical reactions such as luminescent immunoassays or enzyme assays. The system comprises image transfer optics, a low-light level digitizing camera with image intensifying microchannel plates, an image process or, and a control computer. The image transfer optics may be a fiber image guide with a bend, or a microscope, to take the light outside of the RF field. Output of the camera is transformed into a localized rate of cumulative digitalized data or enhanced video display or hard-copy images. The system may be used as a luminescent microdosimetry device for radiofrequency or microwave radiation, as a thermal dosimeter, or in the dosimetry of ultra-sound (sonoluminescence) or ionizing radiation. It provides a near-real-time system capable of measuring the extremely low light levels from luminescent reactions in electromagnetic fields in the areas of chemiluminescence assays and thermal microdosimetry, and is capable of near-real-time imaging of the sample to allow spatial distribution analysis of the reaction. It can be used to instrument three distinctly different irradiation configurations, comprising (1) RF waveguide irradiation of a small Petri-dish-shaped sample cell, (2) RF irradiation of samples in a microscope for the microscopie imaging and measurement, and (3) RF irradiation of small to human body-sized samples in an anechoic chamber.

  12. Draft Genome Sequence of Two Sphingopyxis sp. Strains, Dominant Members of the Bacterial Community Associated with a Drinking Water Distribution System Simulator

    Science.gov (United States)

    We report the draft genome of two Sphingopyxis spp. strains isolated from a chloraminated drinking water distribution system simulator. Both strains are ubiquitous residents and early colonizers of water distribution systems. Genomic annotation identified a class 1 integron (in...

  13. Luminescence, virulence and quorum sensing signal production by pathogenic Vibrio campbellii and Vibrio harveyi isolates.

    Science.gov (United States)

    Defoirdt, T; Verstraete, W; Bossier, P

    2008-05-01

    To study the relationship between luminescence, autoinducer production and virulence of pathogenic vibrios. Luminescence, quorum sensing signal production and virulence towards brine shrimp nauplii of 13 Vibrio campbellii and Vibrio harveyi strains were studied. Although only two of the tested strains were brightly luminescent, all of them were shown to produce the three different types of quorum sensing signals known to be produced by Vibrio harveyi. Cell-free culture fluids of all strains significantly induced bioluminescence in the cholerae autoinducer 1, autoinducer 2 and harveyi autoinducer 1 reporter strains JAF375, JMH597 and JMH612, respectively. There was no relation between luminescence and signal production and virulence towards brine shrimp. There is a large difference between different strains of Vibrio campbellii and Vibrio harveyi with respect to bioluminescence. However, this is not reflected in signal production and virulence towards gnotobiotic brine shrimp. Moreover, there seems to be no relation between quorum sensing signal production and virulence towards brine shrimp. The results presented here indicate that strains that are most brightly luminescent are not necessarily the most virulent ones and that the lower virulence of some of the strains is not due to a lack of autoinducer production.

  14. Interactions between bicarbonate, potassium, and magnesium, and sulfur-dependent induction of luminescence in Vibrio fischeri.

    Science.gov (United States)

    Tabei, Yosuke; Era, Mariko; Ogawa, Akane; Morita, Hiroshi

    2012-06-01

    In spite of its central importance in research efforts, the relationship between seawater compounds and bacterial luminescence has not previously been investigated in detail. Thus, in this study, we investigated the effect of cations (Na(+) , K(+) , NH(4) (+) , Mg(2+) , and Ca(2+) ) and anions (Cl(-) , HCO(3) (-) , CO(3) (2-) , and NO(3) (-) ) on the induction of both inorganic (sulfate, sulfite, and thiosulfate) and organic (L-cysteine and L-cystine) sulfur-dependent luminescence in Vibrio fischeri. We found that HCO(3) (-) (bicarbonate) and CO(3) (2-) (carbonate), in the form of various compounds, had a stimulatory effect on sulfur-dependent luminescence. The luminescence induced by bicarbonate was further promoted by the addition of magnesium. Potassium also increased sulfur-dependent luminescence when sulfate or thiosulfate was supplied as the sole sulfur source, but not when sulfite, L-cysteine, or L-cystine was supplied. The positive effect of potassium was accelerated by the addition of magnesium and/or calcium. Furthermore, the additional supply of magnesium improved the induction of sulfite- or L-cysteine-dependent luminescence, but not the l-cystine-dependent type. These results suggest that sulfur-dependent luminescence of V. fischeri under nutrient-starved conditions is mainly controlled by bicarbonate, carbonate, and potassium. In addition, our results indicate that an additional supply of magnesium is effective for increasing V. fischeri luminescence. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Investigation of lactic acid bacterial strains for meat fermentation and the product's antioxidant and angiotensin-I-converting-enzyme inhibitory activities.

    Science.gov (United States)

    Takeda, Shiro; Matsufuji, Hisashi; Nakade, Koji; Takenoyama, Shin-Ichi; Ahhmed, Abdulatef; Sakata, Ryoichi; Kawahara, Satoshi; Muguruma, Michio

    2017-03-01

    In the lactic acid bacteria (LAB) strains screened from our LAB collection, Lactobacillus (L.) sakei strain no. 23 and L. curvatus strain no. 28 degraded meat protein and tolerated salt and nitrite in vitro. Fermented sausages inoculated strains no. 23 and no. 28 showed not only favorable increases in viable LAB counts and reduced pH, but also the degradation of meat protein. The sausages fermented with these strains showed significantly higher antioxidant activity than those without LAB or fermented by each LAB type strain. Angiotensin-I-converting-enzyme (ACE) inhibitory activity was also significantly higher in the sausages fermented with strain no. 23 than in those fermented with the type strain. Higher ACE inhibitory activity was also observed in the sausages fermented with strain no. 28, but did not differ significantly from those with the type strain. An analysis of the proteolysis and degradation products formed by each LAB in sausages suggested that those bioactivities yielded fermentation products such as peptides. Therefore, LAB starters that can adequately ferment meat, such as strains no. 23 and no. 28, should contribute to the production of bioactive compounds in meat products. © 2016 Japanese Society of Animal Science.

  16. Luminescence dating of Netherland's sediments

    NARCIS (Netherlands)

    Wallinga, J.; Davids, F.; Dijkmans, J.W.A.

    2007-01-01

    Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we revity: 1) the development of the methodology, 2) tests of the reliability of luminescence dating on Netherlands' sediments;

  17. Luminescence from metals and insulators

    International Nuclear Information System (INIS)

    Crawford, O.H.

    1985-01-01

    The term luminescence is normally applied to light emission that is not explainable by the mechanisms discussed by the other speakers in this meeting. Specifically, it is not transition radiation, surface plasmon radiation, or bremsstrahlung. One normally thinks of luminescence as arising from one-electron transitions within a medium. This talk consists of an overview of luminescence from condensed matter under irradiation by either energetic particles or photons. The author begins with organic molecules, where luminescence is best understood, and then discusses inorganic insulators and metals. Finally, the dependence of yield upon projectile species and velocity is discussed, and predictions are made concerning the relative effectiveness of electrons, protons, and hydrogen atoms in exciting luminescence

  18. LUMINESCENCE DETERMINATION OF ETODOLAC

    Directory of Open Access Journals (Sweden)

    A. V. Yegorova

    2015-02-01

    Full Text Available A highly sensitive, simple and rapid method for determination of non-steroidal anti- inflammatory drug – etodolac (Et in washings from surfaces of pharmaceutical equipment have been proposed. The intensity of native luminescence of water-n-propanol solutions of etodolac (λex= 274 nm; λlum= 350 nm was used as the analytical signal. The calibration graph is linear in the concentration range 0.014-2.3 μg/ml, the limit of detection is 0.5 ng/ml.

  19. Luminescence dating in archaeology

    International Nuclear Information System (INIS)

    Wintle, A.G.

    2001-01-01

    Thermoluminescence (TL) dating is routinely applied to burnt lithic material. Simple fires are capable of enabling stones weighing a few hundred grams to reach 450 o C, thus zeroing the TL signal. TL dates have been obtained for Upper and Lower Paleolithic sites in Europe and the Near East. TL dating continues to be used for dating pottery and for authentification of ceramic works of art. Some recent studies report the use of optically stimulated luminescence (OSL) (also know as photoluminescence) for dating very small samples of quartz, e.g. from small pieces of pottery or frm metallurgical slag The major recent advance has been in the development of a reliable laboratory procedure for using the OSL signal from quartz to obtain the past radiation exposure. The quartz OSL signal is extremely sensitive to light and is reduced to a negligible level on exposure to direct sunlight for radionuclides during burial, signal to date san.sized quartz grains extracted from sediments, The OSL signal is stimulated by 470 nm light from emitting diodes and the detected using flirters centred on 340 nm A similar signal can be obtained from feldspar grain when are exposed to infrared wavelengths around 880 nm. The infrared stimulated luminescence (IRSL) signals is also rapidly depleted by exposure to sunlight, and dating of colluvial deposits from archaeological sites has been reported

  20. Wpływ szczepów bakterii wyizolowanych z hydroponicznej uprawy sałaty (Lactuca sativa L. na wzrost siewek sałaty, rosnących w obecnosci rożnych form pożywienia azotowego [Influence of bacterial strains isolated from hydroponic cultures of lettuce (Lactuca sativa L. on the growth of lettuce seedlings growing in the presence of various forms of nitrogen nutrition

    Directory of Open Access Journals (Sweden)

    Z. Kobierzyńska-Gołąb

    2015-06-01

    Full Text Available 320 bacterial strains isolated from the surface of cultivated plants, as well as from other parts of hydroponic cultures showed stimulating (49 bacterial strains or inhibitory (9 bacterial strains properties in respect to the investigated plant. The following bacteria were isolated: Pseudomonas, Flavobacterium, Agrobacterium, Achromobacter and Chromobacterium. The effects of active bacterial strains on the growth of seedlings were investigated in dependence on the kind of inorganic form of nitrogen present in the nutrient solutions. The same bacterial strains exerted a stimulating effect on seedlings growing on nitrates, weaker stimulation was observed in cultures with ammonium nitrate; the growth of lettuce seedlings on nutrient solution with ammonium only, was, as a rule, inhibited by the bacteria.

  1. Bioleaching of Zn, Ni and Fe from contaminated sediments of water reservoir Ružín I with using heterotrophic bacterial strains

    Directory of Open Access Journals (Sweden)

    Katarína Jablonovská

    2012-12-01

    Full Text Available This study investigates the bioleaching of the zinc polluted sediment from water reservoir Ružín I using heterotrophic bacterialstrains ubiquitous in sediment environment. The effect of bacterial activity, pH, iron solubilization and precipitation and bioleachingmedium were evaluated. The pH value controls the bacterial activity during the leaching process. Addition of glucose to the bioleachingmedium accelerated the bioleaching rate. The results indicates, that the leachibility of zinc depend on the geochemical formsand surface interaction between metal and sediment fraction. Sequential chemical extraction confirm, that Zn was predominantly boundto the iron-manganese oxides.

  2. Plant growth promotion properties of bacterial strains isolated from the rhizosphere of the Jerusalem artichoke (Helianthus tuberosus L.) adapted to saline-alkaline soils and their effect on wheat growth.

    Science.gov (United States)

    Liu, Xiaolin; Li, Xiangyue; Li, Yan; Li, Runzhi; Xie, Zhihong

    2017-03-01

    The Jerusalem artichoke (JA; Helianthus tuberosus), known to be tolerant to saline-alkaline soil conditions, has been cultivated for many years in the Yellow River delta, Shandong Province coastal zone, in China. The aim of our study was to isolate nitrogen-fixing bacteria colonizing the rhizosphere of JA and to characterize other plant growth promotion properties. The ultimate goal was to identify isolates that could be used as inoculants benefiting an economic crop, in particular for improving wheat growth production in the Yellow River delta. Bacterial strains were isolated from the rhizosphere soil of JA on the basis of growth on nitrogen-free Ashby medium. Identification and phylogenetic analysis was performed after nucleotide sequencing of 16S rRNA gene. Plant-growth-promoting traits, such as nitrogen fixation activity, phosphate solubilization activity, indole-3-acetic acid production, were determined using conventional methods. Eleven strains were isolated and 6 of them were further examined for their level of salt tolerance and their effect on plant growth promotion. Inoculation of Enterobacter sp. strain N10 on JA and wheat led to significant increases in both root and shoot dry mass and shoot height. Enterobacter sp. strain N10 appeared to be the best plant-growth-promoting rhizobacteria to increase wheat productivity in future field applications.

  3. Bacterial bioluminescence regulates expression of a host cryptochrome gene in the squid-Vibrio symbiosis.

    Science.gov (United States)

    Heath-Heckman, Elizabeth A C; Peyer, Suzanne M; Whistler, Cheryl A; Apicella, Michael A; Goldman, William E; McFall-Ngai, Margaret J

    2013-04-02

    The symbiosis between the squid Euprymna scolopes and its luminous symbiont, Vibrio fischeri, is characterized by daily transcriptional rhythms in both partners and daily fluctuations in symbiont luminescence. In this study, we sought to determine whether symbionts affect host transcriptional rhythms. We identified two transcripts in host tissues (E. scolopes cry1 [escry1] and escry2) that encode cryptochromes, proteins that influence circadian rhythms in other systems. Both genes cycled daily in the head of the squid, with a pattern similar to that of other animals, in which expression of certain cry genes is entrained by environmental light. In contrast, escry1 expression cycled in the symbiont-colonized light organ with 8-fold upregulation coincident with the rhythms of bacterial luminescence, which are offset from the day/night light regime. Colonization of the juvenile light organ by symbionts was required for induction of escry1 cycling. Further, analysis with a mutant strain defective in light production showed that symbiont luminescence is essential for cycling of escry1; this defect could be complemented by presentation of exogenous blue light. However, blue-light exposure alone did not induce cycling in nonsymbiotic animals, but addition of molecules of the symbiont cell envelope to light-exposed animals did recover significant cycling activity, showing that light acts in synergy with other symbiont features to induce cycling. While symbiont luminescence may be a character specific to rhythms of the squid-vibrio association, resident microbial partners could similarly influence well-documented daily rhythms in other systems, such as the mammalian gut.

  4. Mesorhizobium bacterial strains isolated from the legume Lotus corniculatus are an alternative source for the production of polyhydroxyalkanoates (PHAs) to obtain bioplastics.

    Science.gov (United States)

    Marcos-García, Marta; García-Fraile, Paula; Filipová, Alena; Menéndez, Esther; Mateos, Pedro F; Velázquez, Encarna; Cajthaml, Tomáš; Rivas, Raúl

    2017-07-01

    Polyhydroxyalkanoic acids (PHAs) are natural polyesters that can be used to produce bioplastics which are biodegradable. Numerous microorganisms accumulate PHAs as energy reserves. Combinations of different PHAs monomers lead to the production of bioplastics with very different properties. In the present work, we show the capability of strains belonging to various phylogenetic lineages within the genus Mesorhizobium, isolated from Lotus corniculatus nodules, to produce different PHA monomers. Among our strains, we found the production of 3-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxydodecanoate, and 3-hydroxyhexadecanoate. Most of the PHA-positive strains were phylogenetically related to the species M. jarvisii. However, our findings suggest that the ability to produce different monomers forming PHAs is strain-dependent.

  5. Thermo-luminescent dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Reither, M; Schorn, B; Schneider, E

    1981-01-01

    The development of paediatric radiology which began in the late 195O's has been characterised by the need to limit the dose of ionising radiation to which the child is subjected. The aim has been to keep radiation exposure as low as possible by the introduction of suitable techniques and by the development of new methods. It is therefore surprising that studies in dosimetry in the paediaytric age range have only been carried out in recent years. One reason for this may have been the fact that a suitable technique of measurement was not available at the time. The introduction of solid state dosimetry based on thermo-luminescence, first into radiotherapy (1968) and subsequently into radiodiagnosis, has made it possible to abandon the previously widely used ionisation chamber. The purpose of the present paper is to indicate the suitability of this form of dose measurement for paediatric radiological purposes and to stimulate its application in this field.

  6. Persistent luminescence nanothermometers

    Science.gov (United States)

    Martín Rodríguez, Emma; López-Peña, Gabriel; Montes, Eduardo; Lifante, Ginés; García Solé, José; Jaque, Daniel; Diaz-Torres, Luis Armando; Salas, Pedro

    2017-08-01

    Persistent phosphorescence nanoparticles emitting in the red and near-infrared spectral regions are strongly demanded as contrast nanoprobes for autofluorescence free bioimaging and biosensing. In this work, we have developed Sr4Al14O25:Eu2+, Cr3+, Nd3+ nanopowders that produce persistent red phosphorescence peaking at 694 nm generated by Cr3+ ions. This emission displays temperature sensitivity in the physiological temperature range (20-60 °C), which makes these nanoparticles potentially useful as fluorescence (contactless) nanothermometers operating without requiring optical excitation. Nd3+ ions, which act as shallow electron traps for the red Cr3+ persistent emission, also display infrared emission bands, extending the fluorescence imaging capability to the second biological window. This unique combination of properties makes these nanoparticles multifunctional luminescent probes with great potential applications in nanomedicine.

  7. A TaqMan-based real time PCR assay for specific detection and quantification of Xylella fastidiosa strains causing bacterial leaf scorch in oleander.

    Science.gov (United States)

    Guan, Wei; Shao, Jonathan; Singh, Raghuwinder; Davis, Robert E; Zhao, Tingchang; Huang, Qi

    2013-02-15

    A TaqMan-based real-time PCR assay was developed for specific detection of strains of X. fastidiosa causing oleander leaf scorch. The assay uses primers WG-OLS-F1 and WG-OLS-R1 and the fluorescent probe WG-OLS-P1, designed based on unique sequences found only in the genome of oleander strain Ann1. The assay is specific, allowing detection of only oleander-infecting strains, not other strains of X. fastidiosa nor other plant-associated bacteria tested. The assay is also sensitive, with a detection limit of 10.4fg DNA of X. fastidiosa per reaction in vitro and in planta. The assay can also be applied to detect low numbers of X. fastidiosa in insect samples, or further developed into a multiplex real-time PCR assay to simultaneously detect and distinguish diverse strains of X. fastidiosa that may occupy the same hosts or insect vectors. Specific and sensitive detection and quantification of oleander strains of X. fastidiosa should be useful for disease diagnosis, epidemiological studies, management of oleander leaf scorch disease, and resistance screening for oleander shrubs. Published by Elsevier B.V.

  8. Hydrocarbon degradation and plant colonization of selected bacterial strains isolated from the rhizsophere and plant interior of Italian ryegrass and Birdsfoot trefoil

    Science.gov (United States)

    Sohail, Y.; Andria, V.; Reichenauer, T. G.; Sessitsch, A.

    2009-04-01

    Hydrocarbon-degrading strains were isolated from the rhizosphere, root and shoot interior of Italian ryegrass (Lolium multiflorum var. Taurus), Birdsfoot trefoil (Lotus corniculatus var. Leo) grown in a soil contaminated with petroleum oil. Strains were tested regarding their phylogeny and their degradation efficiency. The most efficient strains were tested regarding their suitability to be applied for phytoremediation of diesel oils. Sterilized and non-sterilized agricultural soil, with and with out compost, were spiked with diesel and used for planting Italian ryegrass and birdsfoot trefoil. Four selected strains with high degradation activities, derived from the rhizosphere and plant interior, were selected for individual inoculation. Plants were harvested at flowering stage and plant biomass and hydrocarbon degradation was determined. Furthermore, it was investigated to which extent the inoculant strains were able to survive and colonize plants. Microbial community structures were analysed by 16S rRNA and alkB gene analysis. Results showed efficient colonization by the inoculant strains and improved degradation by the application of compost combined with inoculation as well as on microbial community structures will be presented.

  9. Reflection measurements for luminescent powders

    Science.gov (United States)

    Kroon, R. E.

    2018-04-01

    Luminescent materials are useful in applications varying from lighting and display technologies to document security features and medical research, amongst many others. Measurement of the excitation range is an important consideration, and absorption bands are often determined from a decrease in the measured diffuse reflectance of the material using a ultraviolet-visible (UV-vis) spectrophotometer with an integrating sphere. Such a system may provide questionable results when used to measure the reflectance of a luminescence material, which is demonstrated for a Tb doped silica phosphor, because the system cannot differentiate between the reflected light and luminescence. It is shown that more reliable results are achieved for this phosphor by measuring the reflectance using a synchronous zero-offset scan in a fluorescence spectrometer equipped with an integrating sphere. This method is therefore recommended instead of traditional reflectance measurements using a UV-vis spectrophotometer for luminescent powders.

  10. Luminescence enhancement in irradiated polyethylene

    International Nuclear Information System (INIS)

    Charlesby, A.; Owen, G.P.

    1976-01-01

    Results are presented for the luminescence decay in polyethylene following irradiation at liquid nitrogen temperature and its enhancement on application of an electric field. It is found that both the luminescence enhancement and its subsequent decay may be described by a model involving electron tunnelling from a monoenergetic trap distribution to the parent positive ion. The possible nature of the trap is briefly discussed. (author)

  11. Investigation of the yield process by deformation luminescence of X-ray irradiated KCl:Ca2+

    International Nuclear Information System (INIS)

    Nakamura, S.; Ida, K.; Ohgaku, T.

    2011-01-01

    It is found that deformation luminescence gives us information about the microscopic yield process of X-ray irradiated KCl:Ca 2+ . The stress-strain curve has a macroscopic yield point. But we find that luminescence appears to start before the macroscopic yield. This means that dislocation begin to move before the macroscopic yield because deformation luminescence is attributed to radiation-induced dislocation motion. The beginning of luminescence is considered to be the microscopic yield. Investigating the dependence of microscopic yield stress on strain rate and impurity concentration gives us additional information. The activation volume obtained from the dependence of microscopic yield stress on strain rate is comparable to the value estimated from the concentration of impurity. Then the dislocation starts to move overcoming impurity-vacancy dipoles as obstacles to dislocation motion. The dislocation density starts to increase at the microscopic yield point and then sharply increases to the macroscopic yield.

  12. Biosynthesis of myristic acid in luminescent bacteria. [Vibrio harveyi

    Energy Technology Data Exchange (ETDEWEB)

    Byers, D.M.

    1987-05-01

    In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with (/sup 14/C) acetate in a nutrient-depleted medium accumulated substantial tree (/sup 14/C)fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with (/sup 14/C)acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition.

  13. Goldenphilicity: Luminescent gold compounds

    International Nuclear Information System (INIS)

    Sansores, L.E.

    2002-01-01

    In the solids and molecules different types of bonds are presented depending on the involved atoms, covalent bonds are common among elements of open shell, where more bond orbitals are filled than anti bond orbitals. It is expected that ionic bonds among closed shell atoms which have charges of opposite sign. Bonds type Van der Waals are presented among molecules which have a bipolar moment. It would not be expected bonds among zero charge species, or more generally with the same nominal charge and in any case the attractive forces would be very small. In fact it is expected that two metallic cations to be repelled each other. There recently is evidence that in organic or organometallic compounds could exist attractive interactions between two cations of the d 8 -d 10 -s 2 families. These bonds are weak but stronger than those of Van der Waals. They are compared with the hydrogen bonds. In this work it was reviewed some examples in which the goldenphilicity plays an important role in the luminescence that the gold complexes present. Examples of mono, bi and trinuclear and the structures that these organometallic compounds could take are examined. (Author)

  14. Antibacterial activity of Artemisia asiatica essential oil against some common respiratory infection causing bacterial strains and its mechanism of action in Haemophilus influenzae.

    Science.gov (United States)

    Huang, Jiehui; Qian, Chao; Xu, Hongjie; Huang, Yanjie

    2018-01-01

    The main objective of the current study was to investigate the chemical composition of the essential oil of Artemisia asiatica together with investigating the antibacterial effects it exerts on several common respiratory infection causing bacteria including Haemophilus influenzae. Its mechanism of action was studied using various state-of-the-art assays like scanning electron microscopy, DNA, RNA and protein leakage assays, growth curve assays etc. The essential oil was extracted from the leaves of A. asiatica by supercritical CO 2 fluid extraction technology. Chemical composition of essential oils was analyzed by gas chromatography-mass-spectrometry (GC-MS). The antibacterial activity was evaluated against 6 bacteria by the paper disc diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC) values of the essential oil were estimated by agar dilution method. The antibacterial mechanism was evaluated by growth curve, the integrity of cell membrane and scanning electronmicroscope (SEM). Gas chromatographic analysis of the A. asiatica essential oil led to the identification of 16 chemical constituents accounting for 97.2% of the total oil composition. The major components were found to be Piperitone, (z)-davanone, p-cymene and 1, 8-cineole. The essential oil showed maximum growth inhibition against Haemophilus influenzae with a zone of inhibition of 24.5 mm and MIC/MBC values of 1.9/4.5 mg/mL respectively. Bacteria treated with the essential oil led to a rapid decrease in the number of viable cells. On adding the essential oil of A. asiatica to the bacterial culture, the constituents of the bacterial cell got released into the medium and this cell constituent release increased with increasing doses of the essential oil. SEM showed that the bacterial cells treated with the essential oil showed damaged cell wall, deformed cell morphology and shrunken cells. Copyright © 2017. Published by Elsevier Ltd.

  15. Luminescence sensitivity changes in quartz

    CERN Document Server

    Wintle, A G

    1999-01-01

    In the luminescence dating of sedimentary or heated quartz, some heat treatment is usually applied to the sample immediately prior to the measurement of the optically stimulated luminescence. In this paper we report experiments on a 30,000-year-old sedimentary quartz, in which we use the luminescence response to a test dose to monitor the changes in sensitivity that are caused by holding the quartz at temperatures from 160 to 280 deg. C for times from 10 s to 22 h. For an optically bleached sample, the monitoring is by both optically stimulated luminescence and the 110 deg. C TL peak; both luminescence signals are shown to have the same sensitisation (i.e. activation energy) characteristics. For natural or laboratory irradiated samples only the 110 deg. C TL peak can be used; sensitivity increases of up to a factor of 1.3 and 3 are observed for the natural and laboratory irradiated aliquots, respectively. Up to four exponential components are used to deconvolve the sensitivity change data; the dominant compon...

  16. Luminescence in medical image science

    Energy Technology Data Exchange (ETDEWEB)

    Kandarakis, I.S., E-mail: kandarakis@teiath.gr

    2016-01-15

    Radiation detection in Medical Imaging is mostly based on the use of luminescent materials (scintillators and phosphors) coupled to optical sensors. Materials are employed in the form of granular screens, structured (needle-like) crystals and single crystal transparent blocks. Storage phosphors are also incorporated in some x-ray imaging plates. Description of detector performance is currently based on quality metrics, such as the Luminescence efficiency, the Modulation Transfer Function (MTF), the Noise Power Spectrum (NPS) and the Detective Quantum Efficiency (DQE) can be defined and evaluated. The aforementioned metrics are experimental evaluated for various materials in the form of screens. A software was designed (MINORE v1) to present image quality measurements in a graphical user interface (GUI) environment. Luminescence efficiency, signal and noise analysis are valuable tools for the evaluation of luminescent materials as candidates for medical imaging detectors. - Highlights: • Luminescence based medical imaging detectors. • Image science: MTF, NPS, DQE. • Phosphors screens light emission efficiency experimental evaluation. • Theoretical models for estimation of phosphor screen properties. • Software for medical image quality metrics.

  17. Biocatalytic Conversion of Avermectin to 4"-Oxo-Avermectin: Characterization of Biocatalytically Active Bacterial Strains and of Cytochrome P450 Monooxygenase Enzymes and Their Genes

    Science.gov (United States)

    Jungmann, Volker; Molnár, István; Hammer, Philip E.; Hill, D. Steven; Zirkle, Ross; Buckel, Thomas G.; Buckel, Dagmar; Ligon, James M.; Pachlatko, J. Paul

    2005-01-01

    4"-Oxo-avermectin is a key intermediate in the manufacture of the agriculturally important insecticide emamectin benzoate from the natural product avermectin. Seventeen biocatalytically active Streptomyces strains with the ability to oxidize avermectin to 4"-oxo-avermectin in a regioselective manner have been discovered in a screen of 3,334 microorganisms. The enzymes responsible for this oxidation reaction in these biocatalytically active strains were found to be cytochrome P450 monooxygenases (CYPs) and were termed Ema1 to Ema17. The genes for Ema1 to Ema17 have been cloned, sequenced, and compared to reveal a new subfamily of CYPs. Ema1 to Ema16 have been overexpressed in Escherichia coli and purified as His-tagged recombinant proteins, and their basic enzyme kinetic parameters have been determined. PMID:16269732

  18. Isolation of high-salinity-tolerant bacterial strains, Enterobacter sp., Serratia sp., Yersinia sp., for nitrification and aerobic denitrification under cyanogenic conditions.

    Science.gov (United States)

    Mpongwana, N; Ntwampe, S K O; Mekuto, L; Akinpelu, E A; Dyantyi, S; Mpentshu, Y

    2016-01-01

    Cyanides (CN(-)) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH(4)-N in the presence of 65.91 mg/L of free cyanide (CN(-)) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH(4)-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h(-1) (I), 4.21 h(-1) (H) and 3.79 h(-1) (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH.

  19. Experimental infection with different bacterial strains in larvae and juvenile Litopenaeus vannamei reared in Santa Catarina State, Brazil = Infecção experimental em larvas e juvenis de Litopaenaeus vannamei cultivados no Estado de Santa Catarina, Brasil

    Directory of Open Access Journals (Sweden)

    Celso Carlos Buglione

    2010-07-01

    Full Text Available This study evaluated the pathogenic characteristics of bacteria isolated from Litopenaeus vannamei during an outbreak at the Laboratory of Marine Shrimp, UFSC, Santa Catarina State, Brazil. Their virulence potential in larvae and juvenile shrimp and theeffects on the total haemocyte count, phenoloxidase activity and serum agglutinate titre were examined after experimental infection. Bacterial strains were isolated from larvae and adult shrimps, identified by the AP120E biochemical system as: two strains of Vibrioalginolyticus, three of Aeromonas salmonicida and one of Pasteurella multocida sp. and Pasteurella sp. All the bacterial strains isolated in this study caused mortality in shrimp. One strain of V. alginolyticus was responsible for 97.3 and 88.7% mortality in larvae and juvenil shrimps, respectively. The shrimp immunological system was influenced by experimental infection with V. alginolyticus. Decrease in the total haemocyte count and increase in the phenoloxidase activity and the serum agglutinate titre (p Este estudo avaliou as características patogênicas de cepas de bactérias isoladas de Litopenaeus vannamei durante surto de mortalidade no Laboratório de Camarões Marinhos, UFSC, Estado de Santa Catarina, Brasil. Seu potencial de virulência em larvas e juvenis de camarão marinho e os efeitos sobre a contagem total de hemócito, atividade de fenoloxidase e título aglutinante do soro foramavaliados após infecção experimental. As cepas bacterianas foram isoladas de larvas e de camarões adultos e identificadas bioquimicamente pelo sistema API20E como: duas cepas de Vibrio alginolyticus, três de Aeromonas salmonicida e uma de Pasteurella sp. e P. multocida. Todas as cepas isoladas provocaram mortalidade em L. vannamei, e uma de V. alginolyticus resultou em mortalidade de 97,3 e 88,7% para larvas e juvenis de camarões, respectivamente. O sistema imunológico dos camarões juvenis sofreu influência da infecção experimental

  20. Degradation and mineralization of 2-chloro-, 3-chloro- and 4-chlorobiphenyl by a newly characterized natural bacterial strain isolated from an electrical transformer fluid-contaminated soil.

    Science.gov (United States)

    Ilori, Matthew O; Robinson, Gary K; Adebusoye, Sunday A

    2008-01-01

    A bacterium classified as Achromobacter xylosoxidans strain IR08 by phenotypic typing coupled with 16S rRNA gene analysis was isolated from a soil contaminated with electrical transformer fluid for over sixty years using Aroclor 1221 as an enrichment substrate. The substrate utilization profiles revealed that IR08 could grow on all three monochlorobiphenyls (CBs), 2,4'- and 4,4'-dichlorobiphenyl as well as 2-chlorobenzoate (2-CBA), 3-CBA, 4-CBA, and 2,3-dichlorobenzoate. Unusually, growth was poorly sustained on biphenyl and benzoate. In growth experiments, IR08 degraded all CBs (0.27 mmol/L) in less than 96 h with concomitant stoichiometric release of inorganic chloride and growth yields were 2-3 times higher than those observed on biphenyl. In contrast to most of the chlorobiphenyl-degrading strains described in the literature, which are reported to form CBA, no metabolite was identified in the culture broth by HPLC analysis. When co-incubated with respective CBs and biphenyl, strain IR08 preferentially utilized the chlorinated analogues in less than 96 h while it took another 264 h before 90% of the initially supplied biphenyl could be degraded. The promotion of co-metabolic transformation of halogenated substrates by the inclusion of their non-halogenated derivatives may not therefore, result in universal benefits.

  1. Luminescent lanthanide coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

    1999-12-13

    One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

  2. Iron control of the Vibrio fischeri luminescence system in Escherichia coli.

    Science.gov (United States)

    Dunlap, P V

    1992-01-01

    Iron influences luminescence in Vibrio fischeri; cultures iron-restricted for growth rate induce luminescence at a lower optical density (OD) than faster growing, iron-replete cultures. An iron restriction effect analogous to that in V. fischeri (slower growth, induction of luminescence at a lower OD) was established using Escherichia coli tonB and tonB+ strains transformed with recombinant plasmids containing the V. fischeri lux genes (luxR luxICDABEG) and grown in the presence and absence of the iron chelator ethylenediamine-di(o-hydroxylphenyl acetic acid) (EDDHA). This permitted the mechanism of iron control of luminescence to be examined. A fur mutant and its parent strain containing the intact lux genes exhibited no difference in the OD at induction of luminescence. Therefore, an iron-binding repressor protein apparently is not involved in iron control of luminescence. Furthermore, in the tonB and in tonB+ strains containing lux plasmids with Mu dI(lacZ) fusions in luxR, levels of beta-galactosidase activity (expression from the luxR promoter) and luciferase activity (expression from the luxICDABEG promoter) both increased by a similar amount (8-9 fold each for tonB, 2-3 fold each for tonB+) in the presence of EDDHA. Similar results were obtained with the luxR gene present on a complementing plasmid. The previously identified regulatory factors that control the lux system (autoinducer-LuxR protein, cyclic AMP-cAMP receptor protein) differentially control expression from the luxR and luxICDABEG promoters, increasing expression from one while decreasing expression from the other. Consequently, these results suggest that the effect of iron on the V. fischeri luminescence system is indirect.

  3. On luminescence lifetimes in quartz

    International Nuclear Information System (INIS)

    Chithambo, M.L.; Galloway, R.B.

    2000-01-01

    In this paper we present results of investigations concerning the time dependence of luminescence emission relative to the time of stimulation in quartz. Measurements of time-resolved spectra were performed on a new versatile pulsed light emitting diode system using 525 nm stimulation, an 11 μs duration pulse, a repetition rate of 11 kHz and a 64 μs dynamic range. Effects on luminescence lifetime resulting from sample treatments such as optical stimulation, irradiation, and preheating, are reported

  4. Luminescent materials and their applications

    CERN Document Server

    Virk, Hardev Singh

    2015-01-01

    It is pertinent to note that Luminescence phenomenon has once again occupied a central stage with the announcement of Nobel Prize in October 2014 to three Japanese scientists. The discovery of Galium Nitride proved to be a revolutionary step forward in creation of Blue LEDs. With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources. The Volume under reference consists of 9 Chapters, written by experts in the area of Luminescent Materials. First 5 Chapters are contributed as Review Papers and the last 4 are based on Research Papers.Chapter

  5. Characterization of bacterial strains isolated from a beef-processing plant following cleaning and disinfection - Influence of isolated strains on biofilm formation by Sakaï and EDL 933 E. coli O157:H7.

    Science.gov (United States)

    Marouani-Gadri, Nesrine; Augier, Gladys; Carpentier, Brigitte

    2009-07-31

    The objective of this study was to investigate the effects on Escherichia coli O157:H7 biofilm formation of bacteria isolated from meat site surfaces following cleaning and disinfection. We first isolated and identified, to the genus level, strains of the latter organisms. Samples were obtained by swabbing the surfaces of equipment or floors over areas ranging from 315 to 3200 cm(2) in a slaughter hall, a meat cutting room and a meat boning room of a meat-processing plant. The number of bacteria recovered from these surfaces ranged from 10(5) CFU/cm(2). In the slaughter hall, stainless steel was in one case one of the most contaminated materials and in other cases one of the less contaminated. The same observation was made for conveyor belts made of polyvinyl chloride in the boning room. Dominant genera in the meat plant were Staphylococcus and Bacillus which were both 34% of the isolates from the slaughter hall and 14 and 4% respectively of the isolates from the cutting room. Randomly selected isolates of each of the genera recovered from the slaughter hall were cultured with E. coli O157:H7 in meat exudate at 15 degrees C to form dual-organism biofilms on polyurethane. In all cases but one, the isolates increased the numbers of attached E. coli O157:H7. The effects ranged from 0.37 to 1.11 for EDL 933 strain and from 0.19 to 1.38 log (CFU/cm(2)) for Sakaï strain. This is the first time that a resident microbiota of a meat-processing plant has been shown to have a favourable effect on E. coli O157:H7 colonization of a solid surface, which is of great interest from a food safety standpoint.

  6. Advantages and disadvantages of luminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Olko, Pawel, E-mail: Pawel.Olko@ifj.edu.p [Institute of Nuclear Physics Polish Academy of Science (IFJ PAN), Krakow (Poland)

    2010-03-15

    Owing to their excellent dosimetric properties, luminescence detectors of ionizing radiation are now extensively applied in individual dosimetry services. The most frequently used personal dosemeters are based on Optically Stimulated Luminescence (OSL), radiophotoluminescence (RPL) or thermoluminescence (TL). Luminescence detectors have also found several applications in clinical dosimetry, especially around new radiation modalities in radiotherapy, such as Intensity Modulated Radiotherapy (IMRT) or ion beam radiotherapy. Requirements of luminescence detectors applied in individual and clinical dosimetry and some recent developments in luminescence of detectors and techniques leading to significant improvements of the functionality and accuracy of dosimetry systems are reviewed and discussed.

  7. Bacterial meningitis

    NARCIS (Netherlands)

    Roos, Karen L.; van de Beek, Diederik

    2010-01-01

    Bacterial meningitis is a neurological emergency. Empiric antimicrobial and adjunctive therapy should be initiated as soon as a single set of blood cultures has been obtained. Clinical signs suggestive of bacterial meningitis include fever, headache, meningismus, vomiting, photophobia, and an

  8. Molecular approaches for bacterial azoreductases

    Directory of Open Access Journals (Sweden)

    Montira Leelakriangsak

    2013-12-01

    Full Text Available Azo dyes are the dominant types of synthetic dyes, widely used in textiles, foods, leather, printing, tattooing, cosmetics, and pharmaceutical industries. Many microorganisms are able to decolorize azo dyes, and there is increasing interest in biological waste treatment methods. Bacterial azoreductases can cleave azo linkages (-N=N- in azo dyes, forming aromatic amines. This review mainly focuses on employing molecular approaches, including gene manipulation and recombinant strains, to study bacterial azoreductases. The construction of the recombinant protein by cloning and the overexpression of azoreductase is described. The mechanisms and function of bacterial azoreductases can be studied by other molecular techniques discussed in this review, such as RT-PCR, southern blot analysis, western blot analysis, zymography, and muta-genesis in order to understand bacterial azoreductase properties, function and application. In addition, understanding the regulation of azoreductase gene expression will lead to the systematic use of gene manipulation in bacterial strains for new strategies in future waste remediation technologies.

  9. Hydrothermal synthesis, characterization and luminescent ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF 4 nanoparticles. JIGMET LADOL HEENA KHAJURIA SONIKA KHAJURIA ... Keywords. Citric acid; X-ray diffraction; down-conversion emission; energy transfer.

  10. Hydrothermal synthesis, characterization and luminescent ...

    Indian Academy of Sciences (India)

    that nanoparticles have cylindrical shape and crystalline nature of nanoparticles was confirmed by SAED patterns. Down- conversion (DC) luminescent properties of doped NaLaF4 were also .... Figure 1 shows the XRPD patterns of undoped NaLaF4 and .... which can be assigned to the transitions from the 7F6 ground.

  11. A portable luminescence dating instrument

    DEFF Research Database (Denmark)

    Kook, M.H.; Murray, A.S.; Lapp, Torben

    2011-01-01

    We describe a portable luminescence reader suitable for use in remote localities in the field. The instrument weighs about 8kg and is based around a 30mm bialkali photomultiplier detecting signals through a glass filter centered on 340nm. Stimulation is by 470nm blue LEDs (24W in total) operating...

  12. Advances in luminescence instrument systems

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Bulur, E.; Duller, G.A.T.

    2000-01-01

    We report on recent advances in the development of luminescence measurement systems and techniques at Riso. These include: (1) optical stimulation units based on new-generation powerful blue light (470 nm) emitting diodes providing up to 28 mW/cm(2) for OSL measurements; (2) an infrared (830 nm...

  13. Studies On Optimization Of Protease Production Using Bacterial Isolate Clri Strain 5468 And Its Application In Dehairing And Hydrolysis Of Tannery Fleshings Solid Waste Management

    Directory of Open Access Journals (Sweden)

    Vimala Devi Seenivasagham

    2015-08-01

    Full Text Available The strain which produces protease was originally isolated characterized in Biotechnology laboratory at CLRI and was maintained. The microorganism was growned on several proteolytic media and the maximum activity was observed. The characterization of enzyme was analysed for different pH temperature size of inoculum inhibitors age of the culture. Then the enzyme was observed for the unhairing of skin and the disadvantage in chemical treatment was studied. The conformation of unhairing was studied using histology studies. The tannery waste solid fleshings as it is cannot be directly disposed off to the environment. It was treated with the microbial proteases. The hydrolysis of waste was done using proteases. The solid waste was converted to protien fat and the salt matter. Future work is to optimize the cheap media for the production of the enzyme for large scale applications in various industries.

  14. Bacterial Prostatitis: Bacterial Virulence, Clinical Outcomes, and New Directions.

    Science.gov (United States)

    Krieger, John N; Thumbikat, Praveen

    2016-02-01

    Four prostatitis syndromes are recognized clinically: acute bacterial prostatitis, chronic bacterial prostatitis, chronic prostatitis/chronic pelvic pain syndrome, and asymptomatic prostatitis. Because Escherichia coli represents the most common cause of bacterial prostatitis, we investigated the importance of bacterial virulence factors and antimicrobial resistance in E. coli strains causing prostatitis and the potential association of these characteristics with clinical outcomes. A structured literature review revealed that we have limited understanding of the virulence-associated characteristics of E. coli causing acute prostatitis. Therefore, we completed a comprehensive microbiological and molecular investigation of a unique strain collection isolated from healthy young men. We also considered new data from an animal model system suggesting certain E. coli might prove important in the etiology of chronic prostatitis/chronic pelvic pain syndrome. Our human data suggest that E. coli needs multiple pathogenicity-associated traits to overcome anatomic and immune responses in healthy young men without urological risk factors. The phylogenetic background and accumulation of an exceptional repertoire of extraintestinal pathogenic virulence-associated genes indicate that these E. coli strains belong to a highly virulent subset of uropathogenic variants. In contrast, antibiotic resistance confers little added advantage to E. coli strains in these healthy outpatients. Our animal model data also suggest that certain pathogenic E. coli may be important in the etiology of chronic prostatitis/chronic pelvic pain syndrome through mechanisms that are dependent on the host genetic background and the virulence of the bacterial strain.

  15. Bacterial Larvicide, Bacillus thuringiensis israelensis Strain AM 65-52 Water Dispersible Granule Formulation Impacts Both Dengue Vector, Aedes aegypti (L.) Population Density and Disease Transmission in Cambodia.

    Science.gov (United States)

    Setha, To; Chantha, Ngan; Benjamin, Seleena; Socheat, Doung

    2016-09-01

    A multi-phased study was conducted in Cambodia from 2005-2011 to measure the impact of larviciding with the bacterial larvicide, Bacillus thuringiensis israelensis (Bti), a water dispersible granule (WG) formulation on the vector, Aedes aegypti (L.) and the epidemiology. In our studies, all in-use containers were treated at 8 g/1000 L, including smaller containers and animal feeders which were found to contribute 23% of Ae aegypti pupae. The treated waters were subjected to routine water exchange activities. Pupal production was suppressed by an average 91% for 8 weeks. Pupal numbers continued to remain significantly lower than the untreated commune (UTC) for 13 weeks post treatment in the peak dengue vector season (ptreated commune. An average 70% of the household harbored 0-5 Ae aegypti mosquitoes per home for 8 weeks post treatment, but in the same period of time >50% of the household in the UTC harbored ≥11 mosquitoes per home. The adult population continued to remain at significantly much lower numbers in the Bti treated commune than in the UTC for 10-12 weeks post treatment (ptreatment in the 6 months monsoon season with complete coverage of the target districts achieved an overall dengue case reduction of 48% in the 6 treated districts compared to the previous year, 2010. Five untreated districts in the same province had an overwhelming increase of 352% of dengue cases during the same period of time. The larvicide efficacy, treatment of all in-use containers at the start of the monsoon season, together with treatment coverage of entire districts interrupted disease transmission in the temephos resistant province.

  16. Interaction of Prevotella intermedia strain 17 leucine-rich repeat domain protein AdpF with eukaryotic cells promotes bacterial internalization.

    Science.gov (United States)

    Sengupta, Dipanwita; Kang, Dae-Joong; Anaya-Bergman, Cecilia; Wyant, Tiana; Ghosh, Arnab K; Miyazaki, Hiroshi; Lewis, Janina P

    2014-06-01

    Prevotella intermedia is an oral bacterium implicated in a variety of oral diseases. Although internalization of this bacterium by nonphagocytic host cells is well established, the molecular players mediating the process are not well known. Here, the properties of a leucine-rich repeat (LRR) domain protein, designated AdpF, are described. This protein contains a leucine-rich region composed of 663 amino acid residues, and molecular modeling shows that it folds into a classical curved solenoid structure. The cell surface localization of recombinant AdpF (rAdpF) was confirmed by electron and confocal microscopy analyses. The recombinant form of this protein bound fibronectin in a dose-dependent manner. Furthermore, the protein was internalized by host cells, with the majority of the process accomplished within 30 min. The internalization of rAdpF was inhibited by nystatin, cytochalasin, latrunculin, nocodazole, and wortmannin, indicating that microtubules, microfilaments, and signal transduction are required for the invasion. It is noteworthy that preincubation of eukaryotic cells with AdpF increased P. intermedia 17 internalization by 5- and 10-fold for HeLa and NIH 3T3 fibroblast cell lines, respectively. The addition of the rAdpF protein was also very effective in inducing bacterial internalization into the oral epithelial cell line HN4, as well as into primary cells, including human oral keratinocytes (HOKs) and human umbilical vein endothelial cells (HUVECs). Finally, cells exposed to P. intermedia 17 internalized the bacteria more readily upon reinfection. Taken together, our data demonstrate that rAdpF plays a role in the internalization of P. intermedia 17 by a variety of host cells.

  17. The effect of sequential dual-gas testing on laser-induced breakdown spectroscopy-based discrimination: Application to brass samples and bacterial strains

    International Nuclear Information System (INIS)

    Rehse, Steven J.; Mohaidat, Qassem I.

    2009-01-01

    Four Cu-Zn brass alloys with different stoichiometries and compositions have been analyzed by laser-induced breakdown spectroscopy (LIBS) using nanosecond laser pulses. The intensities of 15 emission lines of copper, zinc, lead, carbon, and aluminum (as well as the environmental contaminants sodium and calcium) were normalized and analyzed with a discriminant function analysis (DFA) to rapidly categorize the samples by alloy. The alloys were tested sequentially in two different noble gases (argon and helium) to enhance discrimination between them. When emission intensities from samples tested sequentially in both gases were combined to form a single 30-spectral line 'fingerprint' of the alloy, an overall 100% correct identification was achieved. This was a modest improvement over using emission intensities acquired in argon gas alone. A similar study was performed to demonstrate an enhanced discrimination between two strains of Escherichia coli (a Gram-negative bacterium) and a Gram-positive bacterium. When emission intensities from bacteria sequentially ablated in two different gas environments were combined, the DFA achieved a 100% categorization accuracy. This result showed the benefit of sequentially testing highly similar samples in two different ambient gases to enhance discrimination between the samples.

  18. Microbiological and Physicochemical Characterization of Small-Scale Cocoa Fermentations and Screening of Yeast and Bacterial Strains To Develop a Defined Starter Culture

    Science.gov (United States)

    Pereira, Gilberto Vinícius de Melo; Miguel, Maria Gabriela da Cruz Pedrozo; Ramos, Cíntia Lacerda

    2012-01-01

    Spontaneous cocoa bean fermentations performed under bench- and pilot-scale conditions were studied using an integrated microbiological approach with culture-dependent and culture-independent techniques, as well as analyses of target metabolites from both cocoa pulp and cotyledons. Both fermentation ecosystems reached equilibrium through a two-phase process, starting with the simultaneous growth of the yeasts (with Saccharomyces cerevisiae as the dominant species) and lactic acid bacteria (LAB) (Lactobacillus fermentum and Lactobacillus plantarum were the dominant species), which were gradually replaced by the acetic acid bacteria (AAB) (Acetobacter tropicalis was the dominant species). In both processes, a sequence of substrate consumption (sucrose, glucose, fructose, and citric acid) and metabolite production kinetics (ethanol, lactic acid, and acetic acid) similar to that of previous, larger-scale fermentation experiments was observed. The technological potential of yeast, LAB, and AAB isolates was evaluated using a polyphasic study that included the measurement of stress-tolerant growth and fermentation kinetic parameters in cocoa pulp media. Overall, strains L. fermentum UFLA CHBE8.12 (citric acid fermenting, lactic acid producing, and tolerant to heat, acid, lactic acid, and ethanol), S. cerevisiae UFLA CHYC7.04 (ethanol producing and tolerant to acid, heat, and ethanol), and Acetobacter tropicalis UFLA CHBE16.01 (ethanol and lactic acid oxidizing, acetic acid producing, and tolerant to acid, heat, acetic acid, and ethanol) were selected to form a cocktail starter culture that should lead to better-controlled and more-reliable cocoa bean fermentation processes. PMID:22636007

  19. Comparative evaluation of culture and PCR for the detection and determination of persistence of bacterial strains and DNAs in the Chinchilla laniger model of otitis media.

    Science.gov (United States)

    Aul, J J; Anderson, K W; Wadowsky, R M; Doyle, W J; Kingsley, L A; Post, J C; Ehrlich, G D

    1998-06-01

    This study was designed to determine the persistence of culturable bacteria versus DNA in the presence of a middle ear effusion in a chinchilla model of otitis media. Cohorts of animals were either infected with an ampicillin-resistant Haemophilus influenzae strain or injected with a tripartite inoculum consisting of freeze-thawed Streptococcus pneumoniae; pasteurized Moraxella catarrhalis; and DNA from H influenzae. The H influenzae-infected animals displayed culture positivity and polymerase chain reaction positivity through day 35. In the chinchillas infected with the low-copy number inocula of S pneumoniae, DNA was not detectable after day 1 from the co-inoculated pasteurized M catarrhalis bacteria or the purified H influenzae DNA; however, amplifiable DNA from the live low-copy number bacteria persisted through day 21 even though they were not culture-positive past day 3. These results demonstrate that DNA, and DNA from intact but nonviable bacteria, does not persist in an amplifiable form for more than a day in the presence of an effusion; however, live bacteria, while not culturable, persist in a viable state for weeks.

  20. Uranyl fluoride luminescence in acidic aqueous solutions

    International Nuclear Information System (INIS)

    Beitz, J.V.; Williams, C.W.

    1996-01-01

    Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 ± 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO 4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO 2 F 2 . Studies on the effect of added LiNO 3 or Na 2 WO 4 ·2H 2 O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF 6 content of WF 6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF 6

  1. Luminescence of LiH(D):Ru monocrystals

    International Nuclear Information System (INIS)

    Sabirzyanov, A.A.; Oparin, D.V.; Pilipenko, G.I.; Gavrilov, F.F.

    1993-01-01

    Luminescence of lithium hydride (deuteride) activated by ruthenium is recorded for the first time. The features connected with the structure and oscillations of the basic lattice are detected in luminescence spectrum. The qualitative model of luminescence spectrum is suggested

  2. Luminescence centers in bismuth orthogermanate

    International Nuclear Information System (INIS)

    Bordun, O.M.

    2001-01-01

    The luminescence and photoexcitation spectra of single crystals,ceramics,and thin films of Bi 4 Ce 3 O 1 2 are studied.The decomposition of the luminescence spectra into elementary components by the Alentsev-Fock method showed that they consist of three bands with maxima at 2.7,2.4,and 2.05 eV.The bands with maxima at 2.7 and 2.4 eV are assigned to the emission of self-trapped Frenkel excitons describing the excited state of a (BiO 6 ) 9- molecular ion. Emission bands with maxima at 2.0 5 eV are assigned to recombination on traps caused by structural defects

  3. X-ray luminescent glasses

    International Nuclear Information System (INIS)

    Takahashi, T.; Yamada, O.

    1981-01-01

    X-ray luminescent glasses comprising a divalent cation such as an alkaline earth metal or other divalent cations such as pb, cd, or zn, and certain rare earth metaphosphates are suitable as vitreous, x-ray phosphors or x-ray luminescent glass fibers in an x-ray intensifying screen. The glasses have the composition n(Mo X p2o5)((1-y)tb2o3 X yce2o3 X 3p2o5) wherein N is greater than zero but less than or equal to 16, M is an alkaline earth metal or other divalent cation such as pb, cd, or zn, and Y is greater than or equal to zero but less than one

  4. Apparatus for reducing solvent luminescence background emissions

    Energy Technology Data Exchange (ETDEWEB)

    Affleck, Rhett L. (Los Alamos, NM); Ambrose, W. Patrick (Los Alamos, NM); Demas, James N. (Charlottesville, VA); Goodwin, Peter M. (Jemez Springs, NM); Johnson, Mitchell E. (Pittsburgh, PA); Keller, Richard A. (Los Alamos, NM); Petty, Jeffrey T. (Los Alamos, NM); Schecker, Jay A. (Sante Fe, NM); Wu, Ming (Los Alamos, NM)

    1998-01-01

    The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

  5. Modern luminescence spectroscopy of minerals and materials

    CERN Document Server

    Gaft, Michael; Panczer, Gerard

    2005-01-01

    Luminescence Spectroscopy of Minerals and Materials presents an overview of the general concepts in luminescence spectroscopy as well as experimental methods and their interpretation. Special emphasis is laid on the fluorescence lifetime and the determination of time-resolved spectra. This method enables the exposure of new luminescence in minerals previously hidden by more intensive centers. Specialists in the fields of solid state physics, chemistry and spectroscopy will find a wealth of new information in this unique book.

  6. Material for a luminescent solar concentrator

    Science.gov (United States)

    Andrews, L.J.

    1984-01-01

    A material for use in a luminescent solar concentrator, formed by ceramitizing the luminescent ion Cr/sup 3 +/ with a transparent ceramic glass containing mullite. The resultant material has tiny Cr/sup 3 +/-bearing crystallites dispersed uniformly through an amorphous glass. The invention combines the high luminescent efficiency of Cr/sup 3 +/ in the crystalline phase with the practical and economical advantages of glass technology.

  7. Handbook of luminescent semiconductor materials

    CERN Document Server

    Bergman, Leah

    2011-01-01

    Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to study semiconductor materials in a variety of applications, including solid-state lighting, solar energy conversion, optical devices, and biological imaging. After introducing basic semiconductor theory and photoluminescence principles, the book focuses

  8. Electrostatic probes in luminescent discharges

    International Nuclear Information System (INIS)

    Cunha Raposo, C. da.

    1980-01-01

    A system to produce luminescent type plasma by continuos discharge and ionization by high frequency was constructed. The ionization was done in the air and in the argon under pressures from 3 to 10 mmHg. The parameters of a non magnetized collisional plasma and the parameters of a magnetized plasma such as, density, eletron temperature and potential, using a Langmuir probe with plane geometry, were determined. (M.C.K.) [pt

  9. Luminescence studies on phosphor screens

    International Nuclear Information System (INIS)

    Panayiotakis, G.; Nomikos, C.; Bakas, A.; Proimos, B.

    1994-01-01

    We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors)

  10. Luminescence studies on phosphor screens

    Energy Technology Data Exchange (ETDEWEB)

    Panayiotakis, G; Nomikos, C; Bakas, A; Proimos, B [Medical Physics Department, University of Patras, 265 00 Patras, Greece (Greece)

    1994-12-31

    We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors). 12 refs, 3 figs.

  11. Optical stimulated luminescence (OSL) dating

    International Nuclear Information System (INIS)

    Banerjee, D.

    1999-01-01

    Since the pioneering work by Huntley et al. (1985), optical dating is being increasingly recognised as an important technique for establishing a time frame of deposition of sediments (Aitken, 1998). Optical dating differs from thermoluminescence (TL) dating in that visible/infrared light from lasers or LEDs (light-emitting-diodes) is used as a means of stimulation, in contrast to thermal stimulation. It has several advantages over TL dating: (i) the resetting of the OSL (optically stimulated luminescence) clock is more effective than that of TL clock; for sediments transported under water or in other situations where the sediment grains have undergone inhomogeneous bleaching, this property ensures that ages based on optical dating are generally more reliable than TL ages, (ii) the optical dating technique is non-destructive, and multiple readouts of the optical signal is possible; this feature has resulted in the development of single-aliquot and single-grain protocols (Murray and Wintle, 1999; Banerjee et al. 1999), (iii) the sample is not heated as in TL; thus, spurious luminescence is avoided and there is a significant reduction in blackbody radiation. Dating of materials which change phase on heating is also practical, and finally, (iv) thermal quenching of luminescence is negligible, allowing accurate estimation of kinetic parameters using standard techniques and providing access to deep OSL traps. This characteristic may be helpful in extending the limits of optical dating beyond the last 150 ka from a global point of view

  12. Methods of producing luminescent images

    International Nuclear Information System (INIS)

    Broadhead, P.; Newman, G.A.

    1977-01-01

    A method is described for producing a luminescent image in a layer of a binding material in which is dispersed a thermoluminescent material. The layer is heated uniformly to a temperature of 80 to 300 0 C and is exposed to luminescence inducing radiation whilst so heated. The preferred exposing radiation is X-rays and preferably the thermoluminescent material is insensitive to electromagnetic radiation of wavelength longer than 300 mm. Information concerning preparation of the luminescent material is given in BP 1,347,672; this material has the advantage that at elevated temperatures it shows increased sensitivity compared with room temperature. At temperatures in the range 80 to 150 0 C the thermoluminescent material exhibits 'afterglow', allowing the image to persist for several seconds after the X-radiation has ceased, thus allowing the image to be retained for visual inspection in this temperature range. At higher temperatures, however, there is negligible 'afterglow'. The thermoluminescent layers so produced are particularly useful as fluoroscopic screens. The preferred method of heating the thermoluminescent material is described in BP 1,354,149. An example is given of the application of the method. (U.K.)

  13. Resonance-shifting luminescent solar concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Giebink, Noel Christopher; Wiederrecht, Gary P.; Wasielewski, Michael R.

    2018-01-23

    An optical system and method to overcome luminescent solar concentrator inefficiencies by resonance-shifting, in which sharply directed emission from a bi-layer cavity into a glass substrate returns to interact with the cavity off-resonance at each subsequent reflection, significantly reducing reabsorption loss en route to the edges. In one embodiment, the system comprises a luminescent solar concentrator comprising a transparent substrate, a luminescent film having a variable thickness; and a low refractive index layer disposed between the transparent substrate and the luminescent film.

  14. Discuss on luminescence dose data analysis technology

    International Nuclear Information System (INIS)

    Ma Xinhua; Xiao Wuyun; Ai Xianyun; Shi Zhilan; Liu Ying

    2009-01-01

    This article describes the development of luminescence dose data measurement and processing technology. General design planning of luminescence dose data measurement and processing technology is put forward with the diverse demands. The emphasis is focused on dose data processing method, luminescence curve analysis method, using of network, mechanics of communication among computers, data base management system of individual dose in this paper. The main methods and skills used in this technology as well as their advantages are also discussed. And it offers general design references for development luminescence dose data processing software. (authors)

  15. Biodegradability of bacterial surfactants.

    Science.gov (United States)

    Lima, Tânia M S; Procópio, Lorena C; Brandão, Felipe D; Carvalho, André M X; Tótola, Marcos R; Borges, Arnaldo C

    2011-06-01

    This work aimed at evaluating the biodegradability of different bacterial surfactants in liquid medium and in soil microcosms. The biodegradability of biosurfactants by pure and mixed bacterial cultures was evaluated through CO(2) evolution. Three bacterial strains, Acinetobacter baumanni LBBMA ES11, Acinetobacter haemolyticus LBBMA 53 and Pseudomonas sp. LBBMA 101B, used the biosurfactants produced by Bacillus sp. LBBMA 111A (mixed lipopeptide), Bacillus subtilis LBBMA 155 (lipopeptide), Flavobacterium sp. LBBMA 168 (mixture of flavolipids), Dietzia Maris LBBMA 191(glycolipid) and Arthrobacter oxydans LBBMA 201(lipopeptide) as carbon sources in minimal medium. The synthetic surfactant sodium dodecyl sulfate (SDS) was also mineralized by these microorganisms, but at a lower rate. CO(2) emitted by a mixed bacterial culture in soil microcosms with biosurfactants was higher than in the microcosm containing SDS. Biosurfactant mineralization in soil was confirmed by the increase in surface tension of the soil aqueous extracts after incubation with the mixed bacterial culture. It can be concluded that, in terms of biodegradability and environmental security, these compounds are more suitable for applications in remediation technologies in comparison to synthetic surfactants. However, more information is needed on structure of biosurfactants, their interaction with soil and contaminants and scale up and cost for biosurfactant production.

  16. Microbiological study of a crushed 'core heart' packaged under sterile atmosphere and isolation of different bacterial strains from the Callovo-Oxfordian argillaceous rock (Bure, France)

    International Nuclear Information System (INIS)

    Mayeux, B.; Daumas, S.; Vinsot, A.; Labat, M.

    2010-01-01

    Document available in extended abstract form only. To study the feasibility of a reversible storage of high activity and long life radioactive waste, many parameters have to be take into account, including microbiological parameters. Indeed, it is necessary to determine the extent of biological reactions that could develop in a disposal. For example, processes such as canister corrosion, retention and transport of radionuclides and gas production may be partially mediated by microbial activities. An initial microbiological characterization of the Callovo- Oxfordian clay-rock was conducted in 2006 by S. Poulain. This previous work highlighted a number of bacterial strains responsible for the disturbances of some geochemical parameters observed in experiments performed in the Andra's Meuse/Haute-Marne Underground Research Laboratory (URL). A thoroughly metabolic study on each isolated strain was then launched after a new phase of microorganism isolation. The purpose of this new study is to analyse the gas produced by bacteria (like CO 2 , H 2 or H 2 S) and the products of their metabolism, in particular corrosive molecules. The microflora was mainly studied on solid samples. These samples came from a 5-m long borehole drilled using aseptic techniques on June, 2009. All parts of the drilling equipment were cleaned with bleach, rinsed with demineralized water, and wrapped in sterile foil and clean plastic, prior to arrival on site. The equipment was handled with ethanol-sterilized gloves and when needed (i.e., after each retraction from the borehole to remove core sections), re-cleaned on site with ethanol. The borehole was drilled with compressed N 2 to avoid air contamination. After retrieval of the cores, they were conditioned on site on a conditioning table prepared for working under clean conditions. The sample were placed in sterile plastic bags, flushed with filter-sterilized N 2 and closed by thermal sealing at ambient temperature. The samples were further

  17. Bacterial cheating limits antibiotic resistance

    Science.gov (United States)

    Xiao Chao, Hui; Yurtsev, Eugene; Datta, Manoshi; Artemova, Tanya; Gore, Jeff

    2012-02-01

    The widespread use of antibiotics has led to the evolution of resistance in bacteria. Bacteria can gain resistance to the antibiotic ampicillin by acquiring a plasmid carrying the gene beta-lactamase, which inactivates the antibiotic. This inactivation may represent a cooperative behavior, as the entire bacterial population benefits from removing the antibiotic. The cooperative nature of this growth suggests that a cheater strain---which does not contribute to breaking down the antibiotic---may be able to take advantage of cells cooperatively inactivating the antibiotic. Here we find experimentally that a ``sensitive'' bacterial strain lacking the plasmid conferring resistance can invade a population of resistant bacteria, even in antibiotic concentrations that should kill the sensitive strain. We observe stable coexistence between the two strains and find that a simple model successfully explains the behavior as a function of antibiotic concentration and cell density. We anticipate that our results will provide insight into the evolutionary origin of phenotypic diversity and cooperative behaviors.

  18. Bacterial prostatitis.

    Science.gov (United States)

    Gill, Bradley C; Shoskes, Daniel A

    2016-02-01

    The review provides the infectious disease community with a urologic perspective on bacterial prostatitis. Specifically, the article briefly reviews the categorization of prostatitis by type and provides a distillation of new findings published on bacterial prostatitis over the past year. It also highlights key points from the established literature. Cross-sectional prostate imaging is becoming more common and may lead to more incidental diagnoses of acute bacterial prostatitis. As drug resistance remains problematic in this condition, the reemergence of older antibiotics such as fosfomycin, has proven beneficial. With regard to chronic bacterial prostatitis, no clear clinical risk factors emerged in a large epidemiological study. However, bacterial biofilm formation has been associated with more severe cases. Surgery has a limited role in bacterial prostatitis and should be reserved for draining of a prostatic abscess or the removal of infected prostatic stones. Prostatitis remains a common and bothersome clinical condition. Antibiotic therapy remains the basis of treatment for both acute and chronic bacterial prostatitis. Further research into improving prostatitis treatment is indicated.

  19. Luminescent converter of neodymium laser radiation

    International Nuclear Information System (INIS)

    Ryba-Romanowski, W.; Golab, S.

    1992-01-01

    The new luminescent converter of neodymium laser radiation has been worked out. Activated inorganic compounds of ytterbium and erbium ions has been used as luminescent agent. The multi-component inorganic glass containing tellurium oxide as well as boron, sodium, magnesium and zinc oxides has been applied as a converter matrix

  20. Receptor-Targeted Luminescent Silver Bionanoparticles

    NARCIS (Netherlands)

    Bunschoten, Anton; Chin, Patrick T.K.; Buckle, Tessa; Linden, van der Marte; Barendregt, Arjan; Verheijen, Marcel A.; Leeuwen, van Fijs W.B.

    2016-01-01

    Luminescent Ag nanoclusters (Ag-NC) provide the next generation in bionanoparticles, wherein the luminescence (650 nm) and large Stokes shift of these inorganic nanoclusters are favorable for biological imaging. By combining these characteristics with those of human serum albumin (HSA; a protein

  1. Kinetics of infrared stimulated luminescence from feldspars

    DEFF Research Database (Denmark)

    Jain, Mayank; Sohbati, Reza; Guralnik, Benny

    2015-01-01

    thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same...

  2. Application of luminescence techniques in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Jungner, H.

    1999-01-01

    Luminescence signals measured from minerals within bricks or ceramic samples can provide information about the absorbed radiation dose. This feature has for several years been used in dating archaeological and geological samples and recently luminescence techniques have been intensively used far ...

  3. Engineering nanoparticles to silence bacterial communication

    Directory of Open Access Journals (Sweden)

    Kristen Publicover Miller

    2015-03-01

    Full Text Available The alarming spread of bacterial resistance to traditional antibiotics has warranted the study of alternative antimicrobial agents. Quorum sensing is a chemical cell-to-cell communication mechanism utilized by bacteria to coordinate group behaviors and establish infections. Quorum sensing is integral to bacterial survival, and therefore provides a unique target for antimicrobial therapy. In this study, silicon dioxide nanoparticles (Si-NP were engineered to target the signaling molecules (i.e. acylhomoserine lactones (HSL used for quorum sensing in order to halt bacterial communication. Specifically, when Si-NP were surface functionalized with beta-cyclodextrin (beta-CD, then added to cultures of bacteria (Vibrio fischeri, whose luminous output depends upon HSL-mediated quorum sensing, the cell-to-cell communication was dramatically reduced. Reductions in luminescence were further verified by quantitative polymerase chain reaction (qPCR analyses of luminescence genes. Binding of AHLs to Si-NPs was examined using nuclear magnetic resonance (NMR spectroscopy. The results indicated that by delivering high concentrations of engineered NPs with associated quenching compounds, the chemical signals were removed from the immediate bacterial environment. In actively-metabolizing cultures, this treatment blocked the ability of bacteria to communicate and regulate quorum sensing, effectively silencing and isolating the cells. Si-NPs provide a scaffold and critical stepping-stone for more pointed developments in antimicrobial therapy, especially with regard to quorum sensing – a target that will reduce resistance pressures imposed by traditional antibiotics.

  4. Time-resolved measurements of luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Collier, Bradley B. [Department of Biomedical Engineering, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States); McShane, Michael J., E-mail: mcshane@tamu.edu [Department of Biomedical Engineering, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States); Materials Science and Engineering Program, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States)

    2013-12-15

    Luminescence sensing and imaging has become more widespread in recent years in a variety of industries including the biomedical and environmental fields. Measurements of luminescence lifetime hold inherent advantages over intensity-based response measurements, and advances in both technology and methods have enabled their use in a broader spectrum of applications including real-time medical diagnostics. This review will focus on recent advances in analytical methods, particularly calculation techniques, including time- and frequency-domain lifetime approaches as well as other time-resolved measurements of luminescence. -- Highlights: • Developments in technology have led to widespread use of luminescence lifetime. • Growing interest for sensing and imaging applications. • Recent advances in approaches to lifetime calculations are reviewed. • Advantages and disadvantages of various methods are weighed. • Other methods for measurement of luminescence lifetime also described.

  5. Time-resolved measurements of luminescence

    International Nuclear Information System (INIS)

    Collier, Bradley B.; McShane, Michael J.

    2013-01-01

    Luminescence sensing and imaging has become more widespread in recent years in a variety of industries including the biomedical and environmental fields. Measurements of luminescence lifetime hold inherent advantages over intensity-based response measurements, and advances in both technology and methods have enabled their use in a broader spectrum of applications including real-time medical diagnostics. This review will focus on recent advances in analytical methods, particularly calculation techniques, including time- and frequency-domain lifetime approaches as well as other time-resolved measurements of luminescence. -- Highlights: • Developments in technology have led to widespread use of luminescence lifetime. • Growing interest for sensing and imaging applications. • Recent advances in approaches to lifetime calculations are reviewed. • Advantages and disadvantages of various methods are weighed. • Other methods for measurement of luminescence lifetime also described

  6. Metal plasmon enhanced europium complex luminescence

    International Nuclear Information System (INIS)

    Liu Feng; Aldea, Gabriela; Nunzi, Jean-Michel

    2010-01-01

    The plasmon enhanced luminescence of a rare-earth complex Tris(6, 6, 7, 7, 8, 8, 8-heptafluoro-2, 2-dimethyl-3, 5-octanedionato) europium (Eu(fod) 3 ) was investigated. A polyvinyl alcohol (PVA) thin film was successfully adopted as a spacer to separate the Eu complex from the silver island film (SIF), and five-fold enhancement of the radiative decay rate of the Eu complex on SIF was demonstrated based on the luminescence intensity and lifetime measurement. Investigation of the distance dependent luminescence indicates that 7 nm is an optimal distance for SIF enhanced Eu luminescence. Plasmon enhanced rare-earth luminescence based on an organic film spacer would find potential applications in plasmon enhanced organic light emitting diode (OLED) devices.

  7. Luminescence detection of irradiated foods

    International Nuclear Information System (INIS)

    Sanderson, D.C.W.

    1990-01-01

    The need for forensic tests to identify irradiated foods has been widely recognised at a time of growing international trade in such products and impending changes in UK and EEC legislation to control the process. This paper outlines the requirements for and of such tests, and discusses recent developments in luminescence approaches aimed at meeting the needs of public analysts, retailers and consumers. Detecting whether or not food has been irradiated, and if so to what dose, is one of the challenges which food irradiation poses to the scientist. (author)

  8. Rupture luminescence from natural fibers

    Science.gov (United States)

    Li, W.; Haneman, D.

    1999-12-01

    Fibers of cotton and wool, and samples of paper, have been ruptured in tension in vacuum and in air, and give detectable luminescence in the visible range. All have a common emission peak at around 2.0 eV, which is ascribed to the deexcitation of states excited by the rupture of organic chain molecule bonds. Rubber bands give stronger emission in air, but no emission in vacuum, suggesting the material breaks only at weak interchain bonds. Mohair, cat, and horse hair also give emission in air. The phenomena reveal effects that would occur widely in nature.

  9. Bacterial Vaginosis

    Science.gov (United States)

    ... Archive STDs Home Page Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes Hepatitis HIV/AIDS & STDs Human Papillomavirus ( ... of getting other STDs, such as chlamydia and gonorrhea . These bacteria can sometimes cause pelvic inflammatory disease ( ...

  10. Ultraviolet radiation response of two heterotropy Antarctic marine bacterial

    International Nuclear Information System (INIS)

    Hernandez, Edgardo A.; Ferreyra, Gustavo A.; Mac Cormack, Walter P.

    2004-01-01

    Two Antarctic marine bacterial strains, were exposed to different irradiance of ultraviolet (UV) solar radiation using several experimental protocols and interferential filters. Results showed that both, UV-A and UV-B radiation produce deleterious effects on two tested bacterial strains. The mortality values under UVB treatments were higher than those observed under UVA treatments. UVvi strain proved to be more resistant to UV radiation than the UVps strain. (author) [es

  11. Detection Antibiotic Resistance of Enviromental Bacterial Strains

    Directory of Open Access Journals (Sweden)

    Huda Zuheir Majeed

    2018-05-01

    Full Text Available      Antibiotics are randomly prescribed  for veterinary and human medication. Antibiotics by little number are used by human , animals are digested uncompletely  in their digestive system and ended up in communal sewage and hospitals, eventually discharge in environmental water sources directly with no processing.     Water itself consider as major factor of dispersal of bacteria between different environmental components. Besides, bacteria had  transferable genetic mobile elements to different sites of soil, water and humans.       Environmental swabs were collected locally including 50 swabs of hospital environment , 15 samples of poultry feces and chicken guts , 20 sample of heavy water and 15 sample of fish tank to identify16 isolate of Staphylococcus (4 isolate of Staphylococus aureus and 12 isolate of coagulase –ve Staphylococcus , 19 isolate of Enterococcus spp. , 7 isolates of Pseudomonas and 5 environment isolates for each Shigella spp.  and Salmonella spp. .           Teicoplanin and Vancomycin sensitivity test of isolates was done , showing that 2out of 16 isolates of Staphylococcus (12.5% were Vancomycin-resistant , and 3out of 19 isolates of Enterococcus (15.7 % were Vancomycin-resistant, while the rest of isolates were Vancomycin- sensitive. From other side , all isolates was Teicoplanin- sensitive except only 1 Enterococcus spp. Isolate which was intermediate . The range of the Vancomycin MIC were (6-64 µg/ml . Vancomycin resistant isolates , showed that some isolates have one plasmid band after Extraction of their DNA.

  12. Bacterial membrane proteomics.

    Science.gov (United States)

    Poetsch, Ansgar; Wolters, Dirk

    2008-10-01

    About one quarter to one third of all bacterial genes encode proteins of the inner or outer bacterial membrane. These proteins perform essential physiological functions, such as the import or export of metabolites, the homeostasis of metal ions, the extrusion of toxic substances or antibiotics, and the generation or conversion of energy. The last years have witnessed completion of a plethora of whole-genome sequences of bacteria important for biotechnology or medicine, which is the foundation for proteome and other functional genome analyses. In this review, we discuss the challenges in membrane proteome analysis, starting from sample preparation and leading to MS-data analysis and quantification. The current state of available proteomics technologies as well as their advantages and disadvantages will be described with a focus on shotgun proteomics. Then, we will briefly introduce the most abundant proteins and protein families present in bacterial membranes before bacterial membrane proteomics studies of the last years will be presented. It will be shown how these works enlarged our knowledge about the physiological adaptations that take place in bacteria during fine chemical production, bioremediation, protein overexpression, and during infections. Furthermore, several examples from literature demonstrate the suitability of membrane proteomics for the identification of antigens and different pathogenic strains, as well as the elucidation of membrane protein structure and function.

  13. Investigation into scanning tunnelling luminescence microscopy

    International Nuclear Information System (INIS)

    Manson-Smith, S.K.

    2001-01-01

    This work reports on the development of a scanning tunnelling luminescence (STL) microscope and its application to the study of Ill-nitride semiconductor materials used in the production of light emitting devices. STL microscopy is a technique which uses the high resolution topographic imaging capabilities of the scanning tunnelling microscope (STM) to generate high resolution luminescence images. The STM tunnelling current acts as a highly localised source of electrons (or holes) which generates luminescence in certain materials. Light generated at the STM tunnelling junction is collected concurrently with the height variation of the tunnelling probe as it is scanned across a sample surface, producing simultaneous topographic and luminescence images. Due to the very localised excitation source, high resolution luminescence images can be obtained. Spectroscopic resolution can be obtained by using filters. Additionally, the variation of luminescence intensity with tunnel current and with bias voltage can provide information on recombination processes and material properties. The design and construction of a scanning tunnelling luminescence microscope is described in detail. Operating under ambient conditions, the microscope has several novel features, including a new type of miniature inertial slider-based approach motor, large solid-angle light collection optical arrangement and a tip-height regulation system which requires the minimum of operator input. (author)

  14. Polymeric Luminescent Compositions Doped with Beta-Diketonates Boron Difluoride as Material for Luminescent Solar Concentrator

    Science.gov (United States)

    Khrebtov, A. A.; Fedorenko, E. V.; Reutov, V. A.

    2017-11-01

    In this paper we investigated polymeric luminescent compositions based on polystyrene doped with beta diketonates boron difluoride. Transparent films with effective absorption in the ultraviolet and blue regions of the spectrum were obtained. Polymeric luminescent compositions based on the mixture of dyes allow expanding the absorption region and increase the radiation shift. A luminescent solar concentrator consisting of a glass plate coated with such film can be used for photovoltaic window application.

  15. Salmonella typhimurium strain SL7207 induces apoptosis and inhibits the growth of HepG2 hepatoma cells in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Baowei Li

    2012-12-01

    Full Text Available Salmonella typhimurium is probably most extensively studied tumor-targeting bacteria and SL7207 is one of its attenuated strains. SL7207 was first made for bacterial vaccine development and its therapeutic efficacy and safety for hepatocellular carcinoma has not been characterized. In this study, the inhibitory ability of SL7207-lux on human hepatoma HepG2 cells was tested in vitro and in vivo. A bacterial luminescent gene cluster (lux CDABE was transfected into SL7207 to better monitor the invasion of the bacteria. The results show that SL7207-lux can rapidly enter HepG2 cells and localize in the cytoplasm. This invasion represses cell proliferation and induces apoptosis. In vivo real-time invasion studies showed that the bacteria gradually accumulate in the tumor. This enrichment was confirmed by anatomic observation at 5 days after inoculation. About 40% of tumor growth was inhibited by SL7207-lux at 34 days post-treatment without significant loss of body weight. The area of necrosis of tumor tissue was clearly increased in the treated group. Bacterial quantification showed that the number of colony-forming units per gram of bacteria within tumor tissue was approximately 1000-fold higher than that of liver and spleen. These data suggest that attenuated S. typhimurium strain SL7207 has potential for the treatment of cancers.

  16. Luminescence properties of uranyl-acetate species

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, Hannes; Moll, Henry [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry

    2017-06-01

    Time-resolved laser-induced fluorescence spectroscopy (TRLFS) was applied to characterize uranium(VI)- acetate species based on their luminescence properties. In contrast to previous interpretations, no indications were detected for the existence of the 1: 3 complex.

  17. Calibration beads containing luminescent lanthanide ion complexes

    Science.gov (United States)

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  18. Towards Luminescence Dating Of Mosaic Glass

    Science.gov (United States)

    Galli, A.; Martini, M.; Sibila, E.; Villa, I.

    The possibility of dating archaeological glass by means of luminescent techniques has been investigated in recent years, despite the difficulties of this application, mainly linked to the amorphous structure of the material. We focused in particular on mosaic glass, after the encouraging results obtained on byzantine and medieval samples. Further studies were devoted to the comprehension of the luminescent mechanisms in silica glasses, and to the investigation of the relationships between luminescence, colouring or opacifier ions and crystalline phase of the vitreous matrix. The results of a study on the dosimetric characteristics of thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) of a few medieval blue-green mosaic glasses from the San Lorenzo church (Milan) are presented, and the experimental protocols established to identify their suitability for dating are discussed.

  19. Controlled fabrication of luminescent and magnetic nanocomposites

    Science.gov (United States)

    Ma, Yingxin; Zhong, Yucheng; Fan, Jing; Huang, Weiren

    2018-03-01

    Luminescent and magnetic multifunctional nanocomposite is in high demand and widely used in many scales, such as drug delivery, bioseparation, chemical/biosensors, and so on. Although lots of strategies have been successfully developed for the demand of multifunctional nanocomposites, it is not easy to prepare multifunctional nanocomposites by using a simple method, and satisfy all kinds of demands simultaneously. In this work, via a facile and versatile method, luminescent nanocrystals and magnetic nanoparticles were successfully synthesized through self-assembly under vigorous stirring and ultrasonic treatment. These multifunctional nanocomposites are not only water stable but also find wide application such as magnetic separation and concentration with a series of moderate speed, multicolor fluorescence at different emission wavelength, high efficiency of the excitation and emission, and so on. By changing different kinds of luminescent nanocrystals and controlling the amount of luminescent and magnetic nanoparticles, a train of multifunctional nanocomposites was successfully fabricated via a versatile and robust method.

  20. Synthesis, crystal structure, theoretical study and luminescence ...

    Indian Academy of Sciences (India)

    and Material Engineering, Jiangnan University, Wuxi 214122, P. R. China. cChina-Australia Joint ... School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China e-mail: ..... The title complex is luminescent.

  1. Recent developments in luminescent solar concentrators

    Science.gov (United States)

    van Sark, W. G. J. H. M.

    2014-10-01

    High efficiency photovoltaic devices combine full solar spectrum absorption and effective generation and collection of charge carriers, while commercial success depends on cost effectiveness in manufacturing. Spectrum modification using down shifting has been demonstrated in luminescent solar concentrators (LSCs) since the 1970s, as a cheap alternative for standard c-Si technology. LSCs consist of a highly transparent plastic plate, in which luminescent species are dispersed, which absorb incident light and emit light at a red-shifted wavelength, with high quantum efficiency. Material issues have hampered efficiency improvements, in particular re-absorption of light emitted by luminescent species and stability of these species. In this contribution, approaches are reviewed on minimizing re-absorption, which should allow surpassing the 10% luminescent solar concentrator efficiency barrier.

  2. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    , which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...... tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters...

  3. Bacterial meningitis

    NARCIS (Netherlands)

    Heckenberg, Sebastiaan G. B.; Brouwer, Matthijs C.; van de Beek, Diederik

    2014-01-01

    Bacterial meningitis is a neurologic emergency. Vaccination against common pathogens has decreased the burden of disease. Early diagnosis and rapid initiation of empiric antimicrobial and adjunctive therapy are vital. Therapy should be initiated as soon as blood cultures have been obtained,

  4. Bacterial lipases

    NARCIS (Netherlands)

    Jaeger, Karl-Erich; Ransac, Stéphane; Dijkstra, Bauke W.; Colson, Charles; Heuvel, Margreet van; Misset, Onno

    Many different bacterial species produce lipases which hydrolyze esters of glycerol with preferably long-chain fatty acids. They act at the interface generated by a hydrophobic lipid substrate in a hydrophilic aqueous medium. A characteristic property of lipases is called interfacial activation,

  5. Bacterial stress

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Bacterial stress. Physicochemical and chemical parameters: temperature, pressure, pH, salt concentration, oxygen, irradiation. Nutritional depravation: nutrient starvation, water shortage. Toxic compounds: Antibiotics, heavy metals, toxins, mutagens. Interactions with other cells: ...

  6. Luminescence basic concepts, applications and instrumentation

    CERN Document Server

    Virk, Hardev Singh

    2014-01-01

    The word luminescence was first used by a German physicist, Eilhardt Wiedemann, in 1888. He also classified luminescence into six kinds according to the method of excitation. No better basis of classification is available today. He recognized photoluminescence, thermoluminescence, electroluminescence, crystalloluminescence, triboluminescence, and chemiluminescence. The designations are obvious, characterized by the prefix. This Volume consists of 9 Chapters, including 8 Review Papers and one Case Study. The first two papers are based on OLEDs. Organic light emitting diodes (OLEDs) have been th

  7. Review of present trends in luminescence research

    International Nuclear Information System (INIS)

    Williams, F.; Delaware Univ., Newark

    1981-01-01

    The difficulties of a comprehensive review of the broad and diverse branches of molecular and solid-state luminescence research are noted. This review is thus limited to selective topics. Some general concepts and trends are then introduced, including: luminescence excitation as a collective excitation of a many-body problem, encompassing in some cases the source and probe in its formulation; continuing trends towards extremal conditions of experiments and towards inhomogeneous and structured materials, from man-made superlattices to biological materials; and increased attention to applications of luminescence research to lamps, displays, solar devices and biological research. Representative recent and new specific research areas include: site selection spectroscopy and 'hole burning'; picosecond delayed coherent anti-Stokes Raman scattering; computer simulation of dynamical processes in luminescence; electron-hole expansion from the Fermi pressure of e-h plasmas; and hot electron phenomena and hot luminescence. Finally some pending problems in luminescence research, such as reconciling the configuration coordinate model and the electronic band theory and clarifying multi-phonon non-radiative processes, are discussed. (orig.)

  8. Plasmon-enhanced optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, E. J.; Baffa, O. [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Ramos, A. P., E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Quimica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    2015-10-15

    Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

  9. Plasmon-enhanced optically stimulated luminescence

    International Nuclear Information System (INIS)

    Guidelli, E. J.; Baffa, O.; Ramos, A. P.

    2015-10-01

    Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

  10. Silica nanoparticles with a substrate switchable luminescence

    International Nuclear Information System (INIS)

    Bochkova, O D; Mustafina, A R; Fedorenko, S V; Konovalov, A I

    2011-01-01

    Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR luminescence (Ru-Yb doped) were obtained by reverse w/o microemulsion procedure. Plenty of luminescent complexes (from 4900 to 10000) encapsulated into each nanoparticle ensures the intensive luminescence of nanoparticles and their applicability as biomarkers. The silica surface decoration by definite anchor groups is the required step for the gaining to these nanoparticles marking and sensing functions. Thus covalent and non-covalent surface modification of these nanoparticles was developed to provide the binding with biotargets and sensing of anions. The dicationic surfactant coating of negatively charged Tb(III)-TCAS doped silica nanoparticles was chosen as the basis for the anion responsible system. The reversible insertion of the quenching anions (namely phenol red) into the surfactant based layer at the surface of luminescent nanoparticles switches off the Tb-centered luminescence. In turn the reversible reestablishment of the luminescence results from the competitive insertion of the non-quenching anions into the surfactant layer at the silica/water interface. The hydrophobic anions exemplified by dodecylsulfates versus hydrophilic ones (hydrophosphates) are preferable in the competition with phenol red anions.

  11. Dielectrophoretic assay of bacterial resistance to antibiotics

    International Nuclear Information System (INIS)

    Johari, Juliana; Huebner, Yvonne; Hull, Judith C; Dale, Jeremy W; Hughes, Michael P

    2003-01-01

    The dielectrophoretic collection spectra of antibiotic-sensitive and antibiotic-resistant strains of Staphylococcus epidermidis have been determined. These indicate that in the absence of antibiotic treatment there is a strong similarity between the dielectric properties of sensitive and resistant strains, and that there is a significant difference between the sensitive strains before and after treatment with the antibiotic streptomycin after 24 h exposure. This method offers possibilities for the assessment of bacterial resistance to antibiotics. (note)

  12. Bacterial growth kinetics

    International Nuclear Information System (INIS)

    Boonkitticharoen, V.; Ehrhardt, J.C.; Kirchner, P.T.

    1989-01-01

    Quantitative measurement of bacterial growth may be made using a radioassay technique. This method measures, by scintillation counting, the 14 CO 2 derived from the bacterial metabolism of a 14 C-labeled substrate. Mathematical growth models may serve as reliable tools for estimation of the generation rate constant (or slope of the growth curve) and provide a basis for evaluating assay performance. Two models, i.e., exponential and logistic, are proposed. Both models yielded an accurate fit to the data from radioactive measurement of bacterial growth. The exponential model yielded high precision values of the generation rate constant, with an average relative standard deviation of 1.2%. Under most conditions the assay demonstrated no changes in the slopes of growth curves when the number of bacteria per inoculation was changed. However, the radiometric assay by scintillation method had a growth-inhibiting effect on a few strains of bacteria. The source of this problem was thought to be hypersensitivity to trace amounts of toluene remaining on the detector

  13. Luminescence studies of molecular materials

    International Nuclear Information System (INIS)

    Miller, P.F.

    2000-01-01

    Molecular materials have been widely studied for their potential uses in novel semiconductor devices. They occupy the intellectually interesting area between molecular and bulk descriptions of matter, and as such often have unique and useful characteristics. The design and engineering of these structures is inter-disciplinary in its nature, embracing the fields of physics, electrical engineering and both synthetic and physical chemistry. In this thesis luminescence studies of molecular materials will be presented that probe the nature of the excited states in two promising semiconductor systems. Luminescence techniques provide a powerful and sensitive tool in the investigation of kinetic pathways of radiative and non-radiative emission from these samples. This is particularly appropriate here, as the materials being studied are of potential use in electroluminescent devices. The suitability of photoluminescence techniques comes from both the electroluminescence and photoluminescence sharing the same emitting state. The first class of material studied here is an organic semiconducting polymer, cyano-substituted polyphenylenevinylene (CN-PPV). Conjugated polymers combine semiconducting electronic properties with favourable processing properties and offer the possibility of tuning their optical and electronic properties chemically. The cyanosubstitution increases the electron affinity of the polymer backbone, facilitating electron injection in light-emitting diodes. The polymers are soluble in solvents such as toluene and chloroform due the presence of alkoxy sidegroups. CdSe semiconductor nanocrystals are the other class of material characterised in this work. Semiconductor nanocrystals exhibit interesting size-tunable optical properties due to the confinement of the electronic wave functions. Characterisation of samples produced by different synthetic routes has been carried out to demonstrate the advantages of a novel synthetic method in terms of physical and

  14. [Bacterial vaginosis].

    Science.gov (United States)

    Romero Herrero, Daniel; Andreu Domingo, Antonia

    2016-07-01

    Bacterial vaginosis (BV) is the main cause of vaginal dysbacteriosis in the women during the reproductive age. It is an entity in which many studies have focused for years and which is still open for discussion topics. This is due to the diversity of microorganisms that cause it and therefore, its difficult treatment. Bacterial vaginosis is probably the result of vaginal colonization by complex bacterial communities, many of them non-cultivable and with interdependent metabolism where anaerobic populations most likely play an important role in its pathogenesis. The main symptoms are an increase of vaginal discharge and the unpleasant smell of it. It can lead to serious consequences for women, such as an increased risk of contracting sexually transmitted infections including human immunodeficiency virus and upper genital tract and pregnancy complications. Gram stain is the gold standard for microbiological diagnosis of BV, but can also be diagnosed using the Amsel clinical criteria. It should not be considered a sexually transmitted disease but it is highly related to sex. Recurrence is the main problem of medical treatment. Apart from BV, there are other dysbacteriosis less characterized like aerobic vaginitis of which further studies are coming slowly but are achieving more attention and consensus among specialists. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  15. Arsenic uptake in bacterial calcite

    Science.gov (United States)

    Catelani, Tiziano; Perito, Brunella; Bellucci, Francesco; Lee, Sang Soo; Fenter, Paul; Newville, Matthew; Rimondi, Valentina; Pratesi, Giovanni; Costagliola, Pilario

    2018-02-01

    Bio-mediated processes for arsenic (As) uptake in calcite were investigated by means of X-ray Diffraction (XRD) and X-ray Absorption Spectroscopy (XAS) coupled with X-ray Fluorescence measurements. The environmental bacterial strain Bacillus licheniformis BD5, sampled at the Bullicame Hot Springs (Viterbo, Central Italy), was used to synthesize calcite from As-enriched growth media. Both liquid and solid cultures were applied to simulate planktonic and biofilm community environments, respectively. Bacterial calcite samples cultured in liquid media had an As enrichment factor (Kd) 50 times higher than that from solid media. The XRD analysis revealed an elongation of the crystal lattice along the c axis (by 0.03 Å) for biogenic calcite, which likely resulted from the substitution of larger arsenate for carbonate in the crystal. The XAS data also showed a clear difference in the oxidation state of sorbed As between bacterial and abiotic calcite. Abiotic chemical processes yielded predominantly As(V) uptake whereas bacterial precipitation processes led to the uptake of both As(III) and As(V). The presence of As(III) in bacterial calcite is proposed to result from subsequent reduction of arsenate to arsenite by bacterial activities. To the best of our knowledge, this is the first experimental observation of the incorporation of As(III) in the calcite crystal lattice, revealing a critical role of biochemical processes for the As cycling in nature.

  16. Arsenic uptake in bacterial calcite

    Energy Technology Data Exchange (ETDEWEB)

    Catelani, Tiziano; Perito, Brunella; Bellucci, Francesco; Lee, Sang Soo; Fenter, Paul; Newville, Matthew G.; Rimondi, Valentina; Pratesi, Giovanni; Costagliola, Pilario

    2018-02-01

    Bio-mediated processes for arsenic (As) uptake in calcite were investigated by means of X-ray Diffraction (XRD) and Xray Absorption Spectroscopy (XAS) coupled with X-ray Fluorescence measurements. The environmental bacterial strain Bacillus licheniformis BD5, sampled at the Bullicame Hot Springs (Viterbo, Central Italy), was used to synthesize calcite from As-enriched growth media. Both liquid and solid cultures were applied to simulate planktonic and biofilm community environments, respectively. Bacterial calcite samples cultured in liquid media had an As enrichment factor (Kd) 50 times higher than that from solid media. The XRD analysis revealed an elongation of the crystal lattice along the c axis (by 0.03Å) for biogenic calcite, which likely resulted from the substitution of larger arsenate for carbonate in the crystal. The XAS data also showed a clear difference in the oxidation state of sorbed As between bacterial and abiotic calcite. Abiotic chemical processes yielded predominantly As(V) uptake whereas bacterial precipitation processes led to the uptake of both As(III) and As(V). The presence of As(III) in bacterial calcite is proposed to result from subsequent reduction of arsenate to arsenite by bacterial activities. To the best of our knowledge, this is the first experimental observation of the incorporation of As(III) in the calcite crystal lattice, revealing a critical role of biochemical processes for the As cycling in nature.

  17. Luminescence dating at Rose cottage cave: a progress report

    CSIR Research Space (South Africa)

    Woodborne, S

    1997-10-01

    Full Text Available Deal with infrared-stimulated luminescence and thermoluminescence dates from Rose Cottage Cave in South Africa. Discrepancy between luminescence and radiocarbon dates; Concentration of radioactive elements in sediments before and after leaching...

  18. Europium enabled luminescent nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Syamchand, S.S., E-mail: syamchand.ss@gmail.com; Sony, G., E-mail: emailtosony@gmail.com

    2015-09-15

    Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

  19. Europium enabled luminescent nanoparticles for biomedical applications

    International Nuclear Information System (INIS)

    Syamchand, S.S.; Sony, G.

    2015-01-01

    Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

  20. Luminescent polymethyl methacrylate modified by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Guilherme F. [Faculdade de Tecnologia de Sao Paulo (FATEC-ZL), Sao Paulo, SP (Brazil); Forster, Pedro L.; Marchini, Leonardo G.; Lugao, Ademar B.; Parra, Duclerc F., E-mail: dfparra@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Thin films of PMMA (polymethyl methacrylate) doped with luminescent complexes have been studied and developed for applications in advanced technologies. The problem of stability of these films is focused in this study. Films stabilization by reaction with fluorinated monomers is a recent study that aims to increase its luminescence properties for long time. The films were prepared by dilution of PMMA in chloroform with addition of europium complex, at proportion of 5% by weight of polymer. The luminescent polymer films were obtained by casting. Thin layer slides of the film were separated in three parts. One was reacted with fluorinated monomers (C{sub 2}F{sub 4}) in closed reactor for 48 hours. A second part was reacted with C{sub 2}F{sub 4} after irradiation in gamma source at 5 kGy in simultaneous process. The last part was used as obtained. The luminescent polymer matrices were characterized using the techniques of infrared (FTIR) and thermogravimetry (TGA/DTG). Samples of the films were, in presence of fluorine monomers, exposed to ionizing radiation in dose of 5 kGy, for react with monomers in the doped polymer surface. In this case the effects of radiation were evaluated on the luminescent films. (author)

  1. Luminescent polymethyl methacrylate modified by gamma radiation

    International Nuclear Information System (INIS)

    Morais, Guilherme F.; Forster, Pedro L.; Marchini, Leonardo G.; Lugao, Ademar B.; Parra, Duclerc F.

    2011-01-01

    Thin films of PMMA (polymethyl methacrylate) doped with luminescent complexes have been studied and developed for applications in advanced technologies. The problem of stability of these films is focused in this study. Films stabilization by reaction with fluorinated monomers is a recent study that aims to increase its luminescence properties for long time. The films were prepared by dilution of PMMA in chloroform with addition of europium complex, at proportion of 5% by weight of polymer. The luminescent polymer films were obtained by casting. Thin layer slides of the film were separated in three parts. One was reacted with fluorinated monomers (C 2 F 4 ) in closed reactor for 48 hours. A second part was reacted with C 2 F 4 after irradiation in gamma source at 5 kGy in simultaneous process. The last part was used as obtained. The luminescent polymer matrices were characterized using the techniques of infrared (FTIR) and thermogravimetry (TGA/DTG). Samples of the films were, in presence of fluorine monomers, exposed to ionizing radiation in dose of 5 kGy, for react with monomers in the doped polymer surface. In this case the effects of radiation were evaluated on the luminescent films. (author)

  2. Bacterial mitosis

    DEFF Research Database (Denmark)

    Møller-Jensen, Jakob; Borch, Jonas; Dam, Mette

    2003-01-01

    Bacterial DNA segregation takes place in an active and ordered fashion. In the case of Escherichia coli plasmid R1, the partitioning system (par) separates paired plasmid copies and moves them to opposite cell poles. Here we address the mechanism by which the three components of the R1 par system...... act together to generate the force required for plasmid movement during segregation. ParR protein binds cooperatively to the centromeric parC DNA region, thereby forming a complex that interacts with the filament-forming actin-like ParM protein in an ATP-dependent manner, suggesting that plasmid...

  3. Luminescence enhancement of uranyl ion by benzoic acid in acetonitrile

    International Nuclear Information System (INIS)

    Satendra Kumar; Maji, S.; Joseph, M.; Sankaran, K.

    2014-01-01

    Uranyl ion is known for its characteristic green luminescence and therefore luminescence spectroscopy is a suitable technique for characterizing different uranyl species. In aqueous medium, luminescence of uranyl ion is generally weak due to its quenching by water molecules and therefore in order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HCIO 4 have been widely used. The other method to enhance the uranyl luminescence is by ligand sensitized luminescence, a method well established for lanthanides. In this work, luminescence of uranyl ion is found to be enhanced by benzoic acid in acetonitrile medium. In aqueous medium benzoic acid does not enhance the uranyl luminescence although it forms 1:1 and 1:2 complexes with uranyl ion. Luminescence spectra of uranyl benzoate revealed that enhancement is due to sensitization of uranyl luminescence by benzoate ions. UV-Vis spectroscopy has been utilized to characterize the specie formed in the in acetonitrile medium. UV-Vis spectroscopy along with luminescence spectra revealed that the specie to be tribenzoate complex of uranyl (UO 2 (C 6 H 5 COO) 3 ) - having D 3 h symmetry. (author)

  4. Study of the liquid water luminescence induced by charged particles

    International Nuclear Information System (INIS)

    Rusu, Mircea; Stere, Oana; Haiduc, Maria; Caramete, Laurentiu

    2004-01-01

    Many observations suggested that liquid water (with impurities) could give a luminescence output when irradiated with charged particles. We investigate theoretical and practical possibility of detecting such luminescence. Preliminary results on this possibility are presented, and a layout of the device proposed for measuring luminescence is given. (authors)

  5. Antibiotic resistance of bacterial biofilms

    DEFF Research Database (Denmark)

    Hoiby, N.; Bjarnsholt, T.; Givskov, M.

    2010-01-01

    A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and DNA. Bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics and disinfectant chemicals as well as resisting phagocytosis...... and other components of the body's defence system. The persistence of, for example, staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients is caused by biofilm-growing mucoid strains....... Characteristically, gradients of nutrients and oxygen exist from the top to the bottom of biofilms and these gradients are associated with decreased bacterial metabolic activity and increased doubling times of the bacterial cells; it is these more or less dormant cells that are responsible for some of the tolerance...

  6. Compatible bacterial mixture, tolerant to desiccation, improves maize plant growth.

    Science.gov (United States)

    Molina-Romero, Dalia; Baez, Antonino; Quintero-Hernández, Verónica; Castañeda-Lucio, Miguel; Fuentes-Ramírez, Luis Ernesto; Bustillos-Cristales, María Del Rocío; Rodríguez-Andrade, Osvaldo; Morales-García, Yolanda Elizabeth; Munive, Antonio; Muñoz-Rojas, Jesús

    2017-01-01

    Plant growth-promoting rhizobacteria (PGPR) increase plant growth and crop productivity. The inoculation of plants with a bacterial mixture (consortium) apparently provides greater benefits to plant growth than inoculation with a single bacterial strain. In the present work, a bacterial consortium was formulated containing four compatible and desiccation-tolerant strains with potential as PGPR. The formulation had one moderately (Pseudomonas putida KT2440) and three highly desiccation-tolerant (Sphingomonas sp. OF178, Azospirillum brasilense Sp7 and Acinetobacter sp. EMM02) strains. The four bacterial strains were able to adhere to seeds and colonize the rhizosphere of plants when applied in both mono-inoculation and multi-inoculation treatments, showing that they can also coexist without antagonistic effects in association with plants. The effects of the bacterial consortium on the growth of blue maize were evaluated. Seeds inoculated with either individual bacterial strains or the bacterial consortium were subjected to two experimental conditions before sowing: normal hydration or desiccation. In general, inoculation with the bacterial consortium increased the shoot and root dry weight, plant height and plant diameter compared to the non-inoculated control or mono-inoculation treatments. The bacterial consortium formulated in this work had greater benefits for blue maize plants even when the inoculated seeds underwent desiccation stress before germination, making this formulation attractive for future field applications.

  7. Compatible bacterial mixture, tolerant to desiccation, improves maize plant growth.

    Directory of Open Access Journals (Sweden)

    Dalia Molina-Romero

    Full Text Available Plant growth-promoting rhizobacteria (PGPR increase plant growth and crop productivity. The inoculation of plants with a bacterial mixture (consortium apparently provides greater benefits to plant growth than inoculation with a single bacterial strain. In the present work, a bacterial consortium was formulated containing four compatible and desiccation-tolerant strains with potential as PGPR. The formulation had one moderately (Pseudomonas putida KT2440 and three highly desiccation-tolerant (Sphingomonas sp. OF178, Azospirillum brasilense Sp7 and Acinetobacter sp. EMM02 strains. The four bacterial strains were able to adhere to seeds and colonize the rhizosphere of plants when applied in both mono-inoculation and multi-inoculation treatments, showing that they can also coexist without antagonistic effects in association with plants. The effects of the bacterial consortium on the growth of blue maize were evaluated. Seeds inoculated with either individual bacterial strains or the bacterial consortium were subjected to two experimental conditions before sowing: normal hydration or desiccation. In general, inoculation with the bacterial consortium increased the shoot and root dry weight, plant height and plant diameter compared to the non-inoculated control or mono-inoculation treatments. The bacterial consortium formulated in this work had greater benefits for blue maize plants even when the inoculated seeds underwent desiccation stress before germination, making this formulation attractive for future field applications.

  8. Cleavage Luminescence from Cleaved Indium Phosphide

    International Nuclear Information System (INIS)

    Dong-Guang, Li

    2008-01-01

    We outline the experiments performed to gain further information about the structure and properties of cleaved InP surfaces. The experiments involved detecting the luminescence produced after cleaving thin InP plates within a high vacuum, by a process of converting the luminescence to an electrical signal which could be amplified and measured accurately. The experimental results show that the detected luminescence durations from cleaved InP are usually only about 10μs. It is believed that this time represents the time of travel of the crack with the actual recombination time being much shorter. Strong signals could also be picked up from cleaved InP in air

  9. Process for obtaining luminescent glass layers

    International Nuclear Information System (INIS)

    Heindi, R.; Robert, A.

    1984-01-01

    Process for obtaining luminescent glass layers, application to the production of devices provided with said layers and to the construction of photoscintillators. The process comprises projecting onto a support, by cathodic sputtering, the material of at least one target, each target including silica and at least one chemical compound able to give luminescent centers, such as a cerium oxide, so as to form at least one luminescent glass layer of the said support. The layer or layers formed preferably undergo a heat treatment such as annealing in order to increase the luminous efficiency thereof. It is in this way possible to form a scintillating glass layer on the previously frosted entrance window of a photomultiplier in order to obtain an integrated photoscintillator

  10. Cerium luminescence in nd0 perovskites

    International Nuclear Information System (INIS)

    Setlur, A.A.; Happek, U.

    2010-01-01

    The luminescence of Ce 3+ in perovskite (ABO 3 ) hosts with nd 0 B-site cations, specifically Ca(Hf,Zr)O 3 and (La,Gd)ScO 3 , is investigated in this report. The energy position of the Ce 3+ excitation and emission bands in these perovskites is compared to those of typical Al 3+ perovskites; we find a Ce 3+ 5d 1 centroid shift and Stokes shift that are larger versus the corresponding values for the Al 3+ perovskites. It is also shown that Ce 3+ luminescence quenching is due to Ce 3+ photoionization. The comparison between these perovskites shows reasonable correlations between Ce 3+ luminescence quenching, the energy position of the Ce 3+ 5d 1 excited state with respect to the host conduction band, and the host composition. - Graphical abstract: Ce 3+ decay times versus temperature for perovskites with nd 0 B-site cations.

  11. Vaginal epithelial cells regulate membrane adhesiveness to co-ordinate bacterial adhesion

    NARCIS (Netherlands)

    Younes, Jessica A.; Klappe, Karin; Kok, Jan Willem; Busscher, Henk J.; Reid, Gregor; van der Mei, Henny C.

    Vaginal epithelium is colonized by different bacterial strains and species. The bacterial composition of vaginal biofilms controls the balance between health and disease. Little is known about the relative contribution of the epithelial and bacterial cell surfaces to bacterial adhesion and whether

  12. Thermal quenching of luminescence processes in feldspars

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Duller, G.A.T.

    1995-01-01

    , which display very different behaviour. The first involves the internal transitions of common transition metal ions. The second is typical of centres not displaying excited states within the band gap that are likely to arise from direct recombination between the conduction band and the ground state......The technique of optically stimulated luminescence has important uses in the dose evaluation of irradiated feldspars. The luminescence process involves the eviction of electrons from donor traps, charge transfer through the conduction band, and recombination at acceptor sites; each...

  13. Evaluation of antifungal activity from Bacillus strains against ...

    African Journals Online (AJOL)

    In this study, 30 bacterial strains isolated from marine biofilms were screened for their antifungal activity against Rhizoctonia solani by dual culture assay. Two bacterial strains, Bacillus subtilis and Bacillus cereus, showed a clear antagonism against R. solani on potato dextrose agar (PDA) medium. The antagonistic activity ...

  14. Bacterial Ecology

    DEFF Research Database (Denmark)

    Fenchel, Tom

    2011-01-01

    compounds these must first be undergo extracellular hydrolysis. Bacteria have a great diversity with respect to types of metabolism that far exceeds the metabolic repertoire of eukaryotic organisms. Bacteria play a fundamental role in the biosphere and certain key processes such as, for example......, the production and oxidation of methane, nitrate reduction and fixation of atmospheric nitrogen are exclusively carried out by different groups of bacteria. Some bacterial species – ‘extremophiles’ – thrive in extreme environments in which no eukaryotic organisms can survive with respect to temperature, salinity...... biogeochemical processes are carried exclusively by bacteria. * Bacteria play an important role in all types of habitats including some that cannot support eukaryotic life....

  15. Antibiotics promote aggregation within aquatic bacterial communities

    Directory of Open Access Journals (Sweden)

    Gianluca eCorno

    2014-07-01

    Full Text Available The release of antibiotics (AB into the environment poses several threats for human health due to potential development of ABresistant natural bacteria. Even though the use of low-dose antibiotics has been promoted in health care and farming, significant amounts of AB are observed in aquatic environments. Knowledge on the impact of AB on natural bacterial communities is missing both in terms of spread and evolution of resistance mechanisms, and of modifications of community composition and productivity. New approaches are required to study the response of microbial communities rather than individual resistance genes. In this study a chemostat-based experiment with 4 coexisting bacterial strains has been performed to mimicking the response of a freshwater bacterial community to the presence of antibiotics in low and high doses. Bacterial abundance rapidly decreased by 75% in the presence of AB, independently of their concentration, and remained constant until the end of the experiment. The bacterial community was mainly dominated by Aeromonas hydrophila and Brevundimonas intermedia while the other two strains, Micrococcus luteus and Rhodococcus sp. never exceed 10%. Interestingly, the bacterial strains, which were isolated at the end of the experiment, were not AB-resistant, while reassembled communities composed of the 4 strains, isolated from treatments under AB stress, significantly raised their performance (growth rate, abundance in the presence of AB compared to the communities reassembled with strains isolated from the treatment without AB. By investigating the phenotypic adaptations of the communities subjected to the different treatments, we found that the presence of AB significantly increased co-aggregation by 5-6 fold.These results represent the first observation of co-aggregation as a successful strategy of AB resistance based on phenotype in aquatic bacterial communities, and can represent a fundamental step in the understanding of

  16. Bacterial Actins.

    Science.gov (United States)

    Izoré, Thierry; van den Ent, Fusinita

    2017-01-01

    A diverse set of protein polymers, structurally related to actin filaments contributes to the organization of bacterial cells as cytomotive or cytoskeletal filaments. This chapter describes actin homologs encoded by bacterial chromosomes. MamK filaments, unique to magnetotactic bacteria, help establishing magnetic biological compasses by interacting with magnetosomes. Magnetosomes are intracellular membrane invaginations containing biomineralized crystals of iron oxide that are positioned by MamK along the long-axis of the cell. FtsA is widespread across bacteria and it is one of the earliest components of the divisome to arrive at midcell, where it anchors the cell division machinery to the membrane. FtsA binds directly to FtsZ filaments and to the membrane through its C-terminus. FtsA shows altered domain architecture when compared to the canonical actin fold. FtsA's subdomain 1C replaces subdomain 1B of other members of the actin family and is located on the opposite side of the molecule. Nevertheless, when FtsA assembles into protofilaments, the protofilament structure is preserved, as subdomain 1C replaces subdomain IB of the following subunit in a canonical actin filament. MreB has an essential role in shape-maintenance of most rod-shaped bacteria. Unusually, MreB filaments assemble from two protofilaments in a flat and antiparallel arrangement. This non-polar architecture implies that both MreB filament ends are structurally identical. MreB filaments bind directly to membranes where they interact with both cytosolic and membrane proteins, thereby forming a key component of the elongasome. MreB filaments in cells are short and dynamic, moving around the long axis of rod-shaped cells, sensing curvature of the membrane and being implicated in peptidoglycan synthesis.

  17. Fabrication of luminescent porous silicon with stain etches and evidence that luminescence originates in amorphous layers

    Science.gov (United States)

    Fathauer, R. W.; George, T.; Ksendzov, A.; Lin, T. L.; Pike, W. T.; Vasquez, R. P.; Wu, Z.-C.

    1992-01-01

    Simple immersion of Si in stain etches of HF:HNO3:H2O or NaNO2 in aqueous HF was used to produce films exhibiting luminescence in the visible similar to that of anodically-etched porous Si. All of the luminescent samples consist of amorphous porous Si in at least the near surface region. No evidence was found for small crystalline regions within these amorphous layers.

  18. Luminescent properties of fluorophosphate glasses with lead chalcogenides molecular clusters

    International Nuclear Information System (INIS)

    Kolobkova, E.V.; Kukushkin, D.S.; Nikonorov, N.V.; Shakhverdov, T.A.; Sidorov, A.I.; Vasiliev, V.N.

    2015-01-01

    Fluorophosphate glasses containing lead, selenium, and sulfur exhibit an intense luminescence in the 400–620 nm spectral region when excited by the 240–420 nm radiation. This luminescence is due to the presence of (PbSe) n and/or (PbS) n molecular clusters in the glasses, which appear in the as-prepared glasses before quantum dots formation. The thermal treatment at temperatures less than the glass transition temperature results in the red-shift of the luminescence bands and in an increase in the luminescence intensity. Heating the thermally treated glass samples leads to the reversible thermal quenching of the luminescence. - Highlights: • Fluorophosphate glasses with Pb, Se, and S ions contain (PbSe) n or (PbS) n molecular clusters. • (PbSe) n and (PbS) n molecular clusters possess luminescence in the visible with UV excitation. • Heating the glass leads to the reversible thermal quenching of the luminescence

  19. Acute toxicity assessment of explosive-contaminated soil extracting solution by luminescent bacteria assays.

    Science.gov (United States)

    Xu, Wenjie; Jiang, Zhenming; Zhao, Quanlin; Zhang, Zhenzhong; Su, Hongping; Gao, Xuewen; Ye, Zhengfang

    2016-11-01

    Explosive-contaminated soil is harmful to people's health and the local ecosystem. The acute toxicity of its extracting solution was tested by bacterial luminescence assay using three kinds of luminescent bacteria to characterize the toxicity of the soil. An orthogonal test L 16 (4 5 ) was designed to optimize the soil extracting conditions. The optimum extracting conditions were obtained when the ultrasonic extraction time, ultrasonic extraction temperature, and the extraction repeat times were 6 h, 40 °C, and three, respectively. Fourier transform infrared spectroscopy (FTIR) results showed that the main components of the contaminated soil's extracting solution were 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO 3 - ); 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO 3 - ); and 2,6-dinitrotoluene (2,6-DNT). Compared with Photobacterium phosphoreum and Vibrio fischeri, Vibrio qinghaiensis sp. Nov. is more suitable for assessing the soil extracting solution's acute toxicity. Soil washing can remove most of the contaminants toxic to luminescent bacterium Vibrio qinghaiensis sp. Nov., suggesting that it may be a potential effective remediation method for explosive-contaminated soil.

  20. Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

    International Nuclear Information System (INIS)

    Guidelli, Eder José; Baffa, Oswaldo; Ramos, Ana Paula

    2016-01-01

    Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films. (paper)

  1. Organic metabolites produced by Vibrio parahaemolyticus strain ...

    African Journals Online (AJOL)

    Identification and action of several antibacterial metabolites produced by a fish pathogen Vibrio parahaemolyticus strain An3 from marine ecosystem of Goa has been demonstrated. Antibacterial activity of the crude cell extract of the test bacterium has been evaluated against indicator pathogenic bacterial strains such as ...

  2. Multistate Luminescent Solar Concentrator "Smart" Windows

    NARCIS (Netherlands)

    Sol, Jeroen A.H.P.; Timmermans, Gilles H.; Breugel, van Abraham J.; Schenning, Albertus P.H.J.; Debije, Michael G.

    2018-01-01

    A supertwist liquid crystalline luminescent solar concentrator (LSC) "smart" window is fabricated which can be switched electrically between three states: one designed for increased light absorption and electrical generation (the "dark" state), one for transparency (the "light" state), and one for

  3. Luminescent Solar Concentrators with Fibre Geometry

    NARCIS (Netherlands)

    Edelenbosch, O.Y.; Fisher, M.; Patrignani, L.; Sark, W.G.J.H.M. van; Chatten, A.J.

    2013-01-01

    The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear

  4. Co-precipitation synthesis and upconversion luminescence ...

    Indian Academy of Sciences (India)

    Introduction. Researches of rare-earth-doped upconversion (UC) materials as fluorescent labels, temperature-sensing probes, solid-state lasers and new generation television screens have recently started to be considered1,2 due to their enhanced luminescent properties induced by the small size. UC process is the gener-.

  5. Holographic patterning of luminescent photopolymer nanocomposites

    International Nuclear Information System (INIS)

    Sakhno, Oksana V.; Smirnova, Tatiana N.; Goldenberg, Leonid M.; Stumpe, Joachim

    2008-01-01

    Volume phase gratings in the photopolymerisable composites, containing luminescent nanoparticles have been fabricated for the first time. Nanoparticles of LaPO 4 , doped by Ce 3+ and Tb 3+ ions (the trade name is REN-X-green) with high luminescence quantum yield were used as a luminescent inorganic additive. The holographic gratings in such materials are formed as a result of the diffusion distribution of the nanoparticles during exposure of photopolymerisable composites to interference pattern. The influence of the pre-polymer formulation and the holographic patterning parameters on the grating formation is comprehensively investigated. The use of the optimised pre-polymer syrup containing two monomers with sufficiently different polymerisation rates allows fabrication of gratings with diffraction efficiency up to 80% at low optical losses (< 5%) (20 μm film thickness). To obtain maximum diffraction efficiency the intensity and the period of the interference pattern were optimised for each formulation. In addition maximum diffraction efficiency was achieved with the nanocomposites containing 30-32 wt.% of nanoparticles. On the other hand the highest possible modulation of the nanoparticles' concentration was obtained for the concentration of about 20 wt.%. In this case maximum ordering of the nanoparticles in the polymer matrix is achieved. The photoluminescence of the nanoparticles within the homogeneous polymer film and within the grating has been measured. The example application of the photopolymerisable composite containing luminescence inorganic nanoparticles in holographic security technology has been demonstrated

  6. Probing luminescence centers in Na rich feldspar

    DEFF Research Database (Denmark)

    Prasad, Amit Kumar; Lapp, Torben; Kook, Myung Ho

    2016-01-01

    our understanding of the luminescence mechanisms and recombination sites, in a sample of Na rich plagioclase feldspar (oligoclase). Both the UV and violet–blue emissions show resonant excitations arising from a distribution of energy levels. We propose, contrary to the general understanding...

  7. Studies of positron induced luminescence from polymers

    International Nuclear Information System (INIS)

    Xu, J.; Hulett, L.D. Jr.; Lewis, T.A.; Tolk, N.H.

    1994-01-01

    Light emission from polymers (anthracene dissolved in polystryrene) induced by low-energy positrons and electrons has been studied. Results indicate a clear difference between optical emissions under positron and electron bombardment. The positron-induced luminescence spectrum is believed to be generated by both collisional and annihilation processes

  8. Combustion synthesis and preliminary luminescence studies of ...

    Indian Academy of Sciences (India)

    The polycrystalline sample of LiBaPO4 : Tb3+ (LBPT) was successfully synthesized by solution combustion synthesis and studied for its luminescence characteristics. The thermoluminescence (TL) glow curve of LBPT material consists of two peaks at 204.54 and 251.21°C. The optimum concentration was 0.005 mol to ...

  9. Co-precipitation synthesis and upconversion luminescence ...

    Indian Academy of Sciences (India)

    ... light: strong green (539 nm), weak red (670 nm) and near-infrared (760 nm). The upconversion luminescence is based on two-photon absorption by the energy transfer from the donor (Yb3+) to the acceptor (Ho3+). All the results indicate that ZrO2:Yb3+-Ho3+ phosphors could be a promising biological labelling material.

  10. Luminescence of porous silicon doped by erbium

    International Nuclear Information System (INIS)

    Bondarenko, V.P.; Vorozov, N.N.; Dolgij, L.N.; Dorofeev, A.M.; Kazyuchits, N.M.; Leshok, A.A.; Troyanova, G.N.

    1996-01-01

    The possibility of the 1.54 μm intensive luminescence in the silicon dense porous layers, doped by erbium, with various structures is shown. Low-porous materials of both porous type on the p-type silicon and porous silicon with wood-like structure on the n + type silicon may be used for formation of light-emitting structures

  11. Probiotic features of Lactobacillus plantarum mutant strains.

    Science.gov (United States)

    Bove, Pasquale; Gallone, Anna; Russo, Pasquale; Capozzi, Vittorio; Albenzio, Marzia; Spano, Giuseppe; Fiocco, Daniela

    2012-10-01

    In this study, the probiotic potential of Lactobacillus plantarum wild-type and derivative mutant strains was investigated. Bacterial survival was evaluated in an in vitro system, simulating the transit along the human oro-gastro-intestinal tract. Interaction with human gut epithelial cells was studied by assessing bacterial adhesive ability to Caco-2 cells and induction of genes involved in innate immunity. L. plantarum strains were resistant to the combined stress at the various steps of the simulated gastrointestinal tract. Major decreases in the viability of L. plantarum cells were observed mainly under drastic acidic conditions (pH ≤ 2.0) of the gastric compartment. Abiotic stresses associated to small intestine poorly affected bacterial viability. All the bacterial strains significantly adhered to Caco-2 cells, with the ΔctsR mutant strain exhibiting the highest adhesion. Induction of immune-related genes resulted higher upon incubation with heat-inactivated bacteria rather than with live ones. For specific genes, a differential transcriptional pattern was observed upon stimulation with different L. plantarum strains, evidencing a possible role of the knocked out bacterial genes in the modulation of host cell response. In particular, cells from Δhsp18.55 and ΔftsH mutants strongly triggered immune defence genes. Our study highlights the relevance of microbial genetic background in host-probiotic interaction and might contribute to identify candidate bacterial genes and molecules involved in probiosis.

  12. Paper-based biodetection using luminescent nanoparticles.

    Science.gov (United States)

    Ju, Qiang; Noor, M Omair; Krull, Ulrich J

    2016-05-10

    Point-of-care and in-field technologies for rapid, sensitive and selective detection of molecular biomarkers have attracted much interest. Rugged bioassay technology capable of fast detection of markers for pathogens and genetic diseases would in particular impact the quality of health care in the developing world, but would also make possible more extensive screening in developed countries to tackle problems such as those associated with water and food quality, and tracking of infectious organisms in hospitals and clinics. Literature trends indicate an increasing interest in the use of nanomaterials, and in particular luminescent nanoparticles, for assay development. These materials may offer attributes for development of assays and sensors that could achieve improvements in analytical figures of merit, and provide practical advantages in sensitivity and stability. There is opportunity for cost-efficiency and technical simplicity by implementation of luminescent nanomaterials as the basis for transduction technology, when combined with the use of paper substrates, and the ubiquitous availability of cell phone cameras and associated infrastructure for optical detection and transmission of results. Luminescent nanoparticles have been described for a broad range of bioanalytical targets including small molecules, oligonucleotides, peptides, proteins, saccharides and whole cells (e.g., cancer diagnostics). The luminescent nanomaterials that are described herein for paper-based bioassays include metal nanoparticles, quantum dots and lanthanide-doped nanocrystals. These nanomaterials often have broad and strong absorption and narrow emission bands that improve opportunity for multiplexed analysis, and can be designed to provide emission at wavelengths that are efficiently processed by conventional digital cameras. Luminescent nanoparticles can be embedded in paper substrates that are designed to direct fluid flow, and the resulting combination of technologies can offer

  13. Quenching methods for background reduction in luminescence-based probe-target binding assays

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Hong [Los Alamos, NM; Goodwin, Peter M [Los Alamos, NM; Keller, Richard A [Los Alamos, NM; Nolan, Rhiannon L [Santa Fe, NM

    2007-04-10

    Background luminescence is reduced from a solution containing unbound luminescent probes, each having a first molecule that attaches to a target molecule and having an attached luminescent moiety, and luminescent probe/target adducts. Quenching capture reagent molecules are formed that are capable of forming an adduct with the unbound luminescent probes and having an attached quencher material effective to quench luminescence of the luminescent moiety. The quencher material of the capture reagent molecules is added to a solution of the luminescent probe/target adducts and binds in a proximity to the luminescent moiety of the unbound luminescent probes to quench luminescence from the luminescent moiety when the luminescent moiety is exposed to exciting illumination. The quencher capture reagent does not bind to probe molecules that are bound to target molecules and the probe/target adduct emission is not quenched.

  14. Dual-In/Out strategy for genes integration into bacterial chromosome: a novel approach to step-by-step construction of plasmid-less marker-less recombinant E. coli strains with predesigned genome structure

    Directory of Open Access Journals (Sweden)

    Biryukova Irina V

    2008-08-01

    Full Text Available Abstract Background The development of modern producer strains with metabolically engineered pathways poses special problems that often require manipulating many genes and expressing them individually at different levels or under separate regulatory controls. The construction of plasmid-less marker-less strains has many advantages for the further practical exploitation of these bacteria in industry. Such producer strains are usually constructed by sequential chromosome modifications including deletions and integration of genetic material. For these purposes complex methods based on in vitro and in vivo recombination processes have been developed. Results Here, we describe the new scheme of insertion of the foreign DNA for step-by-step construction of plasmid-less marker-less recombinant E. coli strains with chromosome structure designed in advance. This strategy, entitled as Dual-In/Out, based on the initial Red-driven insertion of artificial φ80-attB sites into desired points of the chromosome followed by two site-specific recombination processes: first, the φ80 system is used for integration of the recombinant DNA based on selective marker-carrier conditionally-replicated plasmid with φ80-attP-site, and second, the λ system is used for excision of inserted vector part, including the plasmid ori-replication and the marker, flanked by λ-attL/R-sites. Conclusion The developed Dual-In/Out strategy is a rather straightforward, but convenient combination of previously developed recombination methods: phages site-specific and general Red/ET-mediated. This new approach allows us to detail the design of future recombinant marker-less strains, carrying, in particular, rather large artificial insertions that could be difficult to introduce by usually used PCR-based Recombineering procedure. The developed strategy is simple and could be particularly useful for construction of strains for the biotechnological industry.

  15. Molecular methods for bacterial genotyping and analyzed gene regions

    Directory of Open Access Journals (Sweden)

    İbrahim Halil Yıldırım1, Seval Cing Yıldırım2, Nadir Koçak3

    2011-06-01

    Full Text Available Bacterial strain typing is an important process for diagnosis, treatment and epidemiological investigations. Current bacterial strain typing methods may be classified into two main categories: phenotyping and genotyping. Phenotypic characters are the reflection of genetic contents. Genotyping, which refers discrimination of bacterial strains based on their genetic content, has recently become widely used for bacterial strain typing. The methods already used in genotypingof bacteria are quite different from each other. In this review we tried to summarize the basic principles of DNA-based methods used in genotyping of bacteria and describe some important DNA regions that are used in genotyping of bacteria. J Microbiol Infect Dis 2011;1(1:42-46.

  16. Sequence and function of LuxO, a negative regulator of luminescence in Vibrio harveyi.

    Science.gov (United States)

    Bassler, B L; Wright, M; Silverman, M R

    1994-05-01

    Density-dependent expression of luminescence in Vibrio harveyi is regulated by the concentration of extracellular signal molecules (autoinducers) in the culture medium. A recombinant clone that restored function to one class of spontaneous dim mutants was found to encode a function required for the density-dependent response. Transposon Tn5 insertions in the recombinant clone were isolated, and the mutations were transferred to the genome of V. harveyi for examination of mutant phenotypes. Expression of luminescence in V. harveyi strains with transposon insertions in one locus, luxO, was independent of the density of the culture and was similar in intensity to the maximal level observed in wild-type bacteria. Sequence analysis of luxO revealed one open reading frame that encoded a protein, LuxO, similar in amino acid sequence to the response regulator domain of the family of two-component, signal transduction proteins. The constitutive phenotype of LuxO- mutants indicates that LuxO acts negatively to control expression of luminescence, and relief of repression by LuxO in the wild type could result from interactions with other components in the Lux signalling system.

  17. Luminescent amine sensor based on europium(III) chelate.

    Science.gov (United States)

    Petrochenkova, Nataliya V; Mirochnik, Anatolii G; Emelina, Tatyana B; Sergeev, Alexander A; Leonov, Andrei A; Voznesenskii, Sergey S

    2018-07-05

    The effect of methylamine vapor on luminescence of Eu(III) tris-benzoylacetonate (I) immobilized in thin-layer chromatography plates has been investigated. It has been revealed that interaction of I with analyte vapor results in increase of the intensity of Eu(III) luminescence. The mechanism of the effect of methylamine vapors on intensification of the Eu(III) luminescence has been suggested using the data of IR spectroscopy and quantum chemistry calculations. The mechanism of luminescence sensitization consists in bonding of an analyte molecule with a water molecule into the coordination sphere of Eu(III). As a result, the bond of a water molecule with the luminescence centre weakens, rigid structural fragment including europium ion, water and methylamine molecules forms. The presence of such fragment must naturally promote decrease of influence of OH-vibrations on luminescence of the complex I. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Structural, electrical and luminescent characteristics of ultraviolet light emitting structures grown by hydride vapor phase epitaxy

    Directory of Open Access Journals (Sweden)

    A.Y. Polyakov

    2017-03-01

    Full Text Available Electrical and luminescent properties of near-UV light emitting diode structures (LEDs prepared by hydride vapor phase epitaxy (HVPE were studied. Variations in photoluminescence and electroluminescence efficiency observed for LEDs grown under nominally similar conditions could be attributed to the difference in the structural quality (dislocation density, density of dislocations agglomerates of the GaN active layers, to the difference in strain relaxation achieved by growth of AlGaN/AlGaN superlattice and to the presence of current leakage channels in current confining AlGaN layers of the double heterostructure.

  19. Neutron dosimetry using optically stimulated luminescence

    International Nuclear Information System (INIS)

    Miller, S.D.; Eschbach, P.A.

    1991-06-01

    The addition of thermoluminescent (TL) materials within hydrogenous matrices to detect neutron-induced proton recoils for radiation dosimetry is a well-known concept. Previous attempts to implement this technique have met with limited success, primarily due to the high temperatures required for TL readout and the low melting temperatures of hydrogen-rich plastics. Research in recent years at Pacific Northwest laboratories (PNL) has produced a new Optically Stimulated Luminescence (OSL) technique known as the Cooled Optically Stimulated Luminescence (COSL) that offers, for the first time, the capability of performing extremely sensitive radiation dosimetry at low temperatures. In addition to its extreme sensitivity, the COSL technique offers multiple readout capability, limited fading in a one-year period, and the capability of analyzing single grains within a hydrogenous matrix. 4 refs., 10 figs

  20. Luminescence properties of a nanoporous freshwater diatom.

    Science.gov (United States)

    Goswami, Bondita; Choudhury, Amarjyoti; Buragohain, Alak K

    2012-01-01

    Freshwater diatom frustules show special optical properties. In this paper we observed luminescence properties of the freshwater diatom Cyclotella meneghiniana. To confirm the morphological properties we present scanning electron microscopy (SEM) images. X-ray diffraction (XRD) studies were carried out to visualize the structural properties of the frustules, confirming that silica present in diatom frustules crystallizes in an α-quartz structure. Study of the optical properties of the silica frustules of diatoms using ultra-violet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy confirmed that the diatom C. meneghiniana shows luminescence in the blue region of the electromagnetic spectrum when irradiated with UV light. This property of diatoms can be exploited to obtain many applications in day-to-day life. Also, using time-resolved photoluminescence spectroscopy (TRPL) it was confirmed that this species of diatom shows bi-exponential decay. Copyright © 2011 John Wiley & Sons, Ltd.

  1. New luminescence measurement facilities in retrospective dosimetry

    DEFF Research Database (Denmark)

    Lapp, Torben; Jain, Mayank; Thomsen, Kristina Jørkov

    2012-01-01

    ), this facility has been used to measure natural doses in feldspar using the decaying NIR RL signal.Secondly, we present a method for mapping radiation field of the built-in 90Sr/90Y β-source and estimating grain-location specific dose-rates. This is important for the accuracy of single grain results, when......This paper gives a review of recent developments in luminescence measurement facilities on the Risø TL/OSL reader including radio-luminescence (RL), exo-electron and violet stimulation attachments, and a method for characterising and if necessary correcting for beta irradiation source non...... radiation field is spatially non-uniform across the sample area. We document the effect of this correction method and further investigate on the effect of lifting the source to achieve a better dose-rate uniformity.Finally we summarise two recently-developed novel facilities to help investigate (i) the time...

  2. The double luminescence of Color Centers

    International Nuclear Information System (INIS)

    Baldacchini, Giuseppe

    2015-01-01

    An experiment on the luminescence of Color Centers (CCs) carried out in 1987 at the ENEA Laboratories in Frascati had a negative result, but subsequent investigations showed that it was not a failure but rather a discovery of a new phenomenon. Since the coming of lasers, CCs in alkali halides have been successfully used as optically active materials, in particular FA Centers. One of these centers, well known for its medium infrared laser emission at 77 K, cooled further to 2 K emitted in the near infrared and without laser effect. Further investigations showed that the double luminescence was a fundamental property unknown until that time. This important discovery was achieved in Frascati because of the existence since 1973 of a solid and extensive expertise in the field of CCs, which continued over time and later on applied to the modern miniaturized photonic devices [it

  3. Anomalous enhancement of nanodiamond luminescence upon heating

    Science.gov (United States)

    Khomich, A. A.; Kudryavtsev, O. S.; Dolenko, T. A.; Shiryaev, A. A.; Fisenko, A. V.; Konov, V. I.; Vlasov, I. I.

    2017-02-01

    Characteristic photoluminescence (PL) of nanodiamonds (ND) of different origin (detonation, HPHT, extracted from meteorite) was studied in situ at high temperatures in the range 20-450 °C. Luminescence was excited using 473 nm laser and recorded in the range 500-800 nm. In contrast to decrease of point defect PL in bulk diamond with temperature, we found that the ND luminescence related to ND surface defects increases almost an order of magnitude upon heating to 200-250 °C. The observed effect reveals that water adsorbed on ND surfaces efficiently quenches PL; water desorption on heating leads to dramatic increase of the radiative de-excitation.

  4. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Boks, N.P.; Norde, W.; Meil, H.C.; Busscher, H.J.

    2008-01-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F-prev) and to detach adhering bacteria (F-det) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the

  5. Uranyl(VI) luminescence spectroscopy at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Steudtner, Robin; Franzen, Carola; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Surface Processes; Haubitz, Toni [Brandenburg Univ. of Technology, Cottbus-Senftenberg (Germany)

    2016-07-01

    We studied the influence of temperature and ionic strength on the luminescence characteristics (band position, decay time and intensity) of the free uranyl ion (UO{sub 2}{sup 2+}) in acidic aqueous solution. Under the chosen conditions an increasing temperature reduced both intensity and luminescence decay time of the UO{sub 2}{sup 2+} luminescence, but the individual U(VI) emission bands did not change.

  6. Method and apparatus for reducing solvent luminescence background emissions

    Energy Technology Data Exchange (ETDEWEB)

    Affleck, Rhett L. (Los Alamos, NM); Ambrose, W. Patrick (Los Alamos, NM); Demas, James N. (Charlottesville, VA); Goodwin, Peter M. (Jemez Springs, NM); Johnson, Mitchell E. (Pittsburgh, PA); Keller, Richard A. (Los Alamos, NM); Petty, Jeffrey T. (Los Alamos, NM); Schecker, Jay A. (Santa Fe, NM); Wu, Ming (Los Alamos, NM)

    1998-01-01

    The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

  7. Ab initio calculations of cross luminescence materials

    International Nuclear Information System (INIS)

    Kanchana, V.

    2016-01-01

    Abintio calculations have been performed to study the structural, electronic, and optical properties of ABX 3 (A=alkali, B=alkaline-earth, and X=halide) compounds. The ground state properties are calculated using the pseudopotential method with the inclusion of van der Waals interaction, which we find inevitable in reproducing the experimental structure properties in alkali iodides because of its layered structure. All calculations were performed using the Full-Potential Linearized Augmented Plane Wave method. The band structures are plotted with various functionals and we find the newly developed Tran and Blaha modified Becke-Johnson potential to improve the band gap significantly. The optical properties such as complex dielectric function, refractive index, and absorption spectra are calculated which clearly reveal the optically isotropic nature of these materials though being structurally anisotropic, which is the key requirement for ceramic scintillators. Cross luminescence materials are very interesting because of its fast decay. One of the major criteria for the cross luminescence to happen is the energy difference between valence band and next deeper core valence band being lesser when compared to energy gap of the compound, so that radiative electronic transition may occur between valence band and core valence band. We found this criteria to be satisfied in all the studied compounds leading to cross luminescence except for KSrI 3 , RbSrI 3 . The present study suggest that among the six compounds studied, CsSrI 3 , CsMgCl 3 , CsCaCl 3 , and CsSrCl 3 compounds are cross luminescence materials, which is well explained from the band structure, optical properties calculations. Chlorides are better scintillators that iodides and CsMgCl 3 is found to be promising one among the studied compounds. Apart from these materials we have also discussed electronic structure and optical properties of other scintillator compounds. (author)

  8. Thermally stimulated luminescence of KDP activated crystals

    International Nuclear Information System (INIS)

    Tagaeva, B.S.

    2005-01-01

    The aim of this work is the study of recombination luminescence pure and doped by the ions Tl, Se, Pb and Cu of crystals double potassium phosphates (KDP) at irradiation by X-rays. It is established that in the given crystals mechanisms for under-threshold defect formation are realize. The impurity ions results the basic crystal light sum redistribution in the TL peaks. Explanations for some phenomena are given. (author)

  9. Process for producing a self luminescent material

    Energy Technology Data Exchange (ETDEWEB)

    Abe, E

    1962-01-28

    A self luminescent material is produced by a process comprising applying a hydroxide or fluoride of promethium-147 suspended in a medium of paraffinic acid to the surface of a fluorescent body. Promethium-147 decays with a half-life of 2.6 years and emits beta-rays but not alpha- and gamma-rays so that it is suitable for manufacturing self luminescent materials. A chloride of promethium-147 cannot be employed because its structure is destroyed by acids. Although fluorides and hydroxides of promethium-147 are difficult to mix with the fluorescent body material, they become mixable when paraffinic acids containing from 12 to 20 carbon atoms, (for example, steric acid, palmitic acid and margaric acid) are used as a medium. In embodiments, the self luminescent materials are prepared by either neutralization of a promethium-147 chloride solution having a specific radioactivity of 1.2 c/cc. with an ammonium hydroxide solution to form gelatinous hydroxide, or the reaction of a promethium-147 chloride solution with H/sub 2/SiF/sub 6/ by heating at 80/sup 0/C to form a fluoride of promethium-147. The products have a specific radioactivity of 8 to 12 mc/g. These products are suspended in vehicles of polystyrene and methacrylic resin to produce the self luminescent coating materials. Tests show that the initical brightness is comparatively high, the decreasing rate of brightness is small, no blackening effects by alpha-rays occur and costs are low. The brightness of the coating containing promethium-147 is 82-85 after 5 days, 100-105 after 100 days and 82-92 after 180 days. With respect to the coating containing radium the values are 31-70 after 5 days, 28-49 after 100 days and 19-31 after 180 days.

  10. Broadband luminescence in liquid-solid transition

    CERN Document Server

    Achilov, M F; Trunilina, O V

    2002-01-01

    Broadband luminescence (BBL) intensity behavior in liquid-solid transition in polyethyleneglycol-600 has been established. Oscillation of BBL intensity observed in liquid-polycrystal transition are not found to observed in liquid-amorphous solid transition. It is shown that application of the theory of electron state tails to interpretation of BBL spectral properties in liquids demands restriction. BBL spectroscopy may be applied for optimization of preparation of polymers with determined properties. (author)

  11. Luminescent Metal Nanoclusters for Potential Chemosensor Applications

    Directory of Open Access Journals (Sweden)

    Muthaiah Shellaiah

    2017-12-01

    Full Text Available Studies of metal nanocluster (M-NCs-based sensors for specific analyte detection have achieved significant progress in recent decades. Ultra-small-size (<2 nm M-NCs consist of several to a few hundred metal atoms and exhibit extraordinary physical and chemical properties. Similar to organic molecules, M-NCs display absorption and emission properties via electronic transitions between energy levels upon interaction with light. As such, researchers tend to apply M-NCs in diverse fields, such as in chemosensors, biological imaging, catalysis, and environmental and electronic devices. Chemo- and bio-sensory uses have been extensively explored with luminescent NCs of Au, Ag, Cu, and Pt as potential sensory materials. Luminescent bi-metallic NCs, such as Au-Ag, Au-Cu, Au-Pd, and Au-Pt have also been used as probes in chemosensory investigations. Both metallic and bi-metallic NCs have been utilized to detect various analytes, such as metal ions, anions, biomolecules, proteins, acidity or alkalinity of a solution (pH, and nucleic acids, at diverse detection ranges and limits. In this review, we have summarized the chemosensory applications of luminescent M-NCs and bi-metallic NCs.

  12. Optically stimulated luminescence (OSL) and some other luminescence images from granite slices exposed with radiations

    International Nuclear Information System (INIS)

    Hashimoto, T.; Notoya, S.; Ojima, T.; Hoteida, M.

    1995-01-01

    Optically stimulated luminescence (OSL) images of some X- and γ-irradiated granite slices were obtained using photon detection through a 570 nm bandpass filter with diode-laser excitation of 910 nm. Alternative photo-induced phosphorescence (PIP) images, which were colour photographed immediately after the sunlight exposure of slice samples, were also found to be helpful in the observation of the luminescence properties and to filter selection for OSL measurements. These OSL and PIP images were compared with some other colour luminescence images, including thermoluminescence images (TLCI) and after-glow images (AGCI). It was obvious that there exists a variety of coloured emissions derived mainly from feldspar constituents and these were found to be dependent on the geological history or metamorphism of the granites. (Author)

  13. Near-Infrared Quantum Cutting Long Persistent Luminescence

    OpenAIRE

    Zou, Zehua; Feng, Lin; Cao, Cheng; Zhang, Jiachi; Wang, Yuhua

    2016-01-01

    By combining the unique features of the quantum cutting luminescence and long persistent luminescence, we design a new concept called ?near-infrared quantum cutting long persistent luminescence (NQPL)?, which makes it possible for us to obtain highly efficient (>100%) near-infrared long persistent luminescence in theory. Guided by the NQPL concept, we fabricate the first NQPL phosphor Ca2Ga2GeO7:Pr3+,Yb3+. It reveals that both the two-step energy transfer of model (I) and the one-step energy ...

  14. Inhibition of luminescence and virulence in the black tiger prawn (Penaeus monodon) pathogen Vibrio harveyi by intercellular signal antagonists.

    Science.gov (United States)

    Manefield, M; Harris, L; Rice, S A; de Nys, R; Kjelleberg, S

    2000-05-01

    Expression of luminescence in the Penaeus monodon pathogen Vibrio harveyi is regulated by an intercellular quorum sensing mechanism involving the synthesis and detection of two signaling molecules, one of which is N-hydroxy butanoyl-L-homoserine lactone and the other of which is uncharacterized. Indirect evidence has suggested that virulence, associated with a toxic extracellular protein, and luminescence in V. harveyi are coregulated. In this study the effects of an acylated homoserine lactone antagonist produced by the marine alga Delisea pulchra on luminescence and toxin production in a virulent strain of V. harveyi were analyzed. Luminescence and toxin production were both inhibited by the signal antagonist at concentrations that had no impact on growth. Toxin production was found to be prematurely induced in V. harveyi cultures incubated in a 10% conditioned medium. Additionally, a significant reduction in the toxicity of concentrated supernatant extracts from V. harveyi cultures incubated in the presence of the signal antagonist, as measured by in vivo toxicity assays in mice and prawns, was observed. These results suggest that intercellular signaling antagonists have potential utility in the control of V. harveyi prawn infections.

  15. Inhibition of Luminescence and Virulence in the Black Tiger Prawn (Penaeus monodon) Pathogen Vibrio harveyi by Intercellular Signal Antagonists

    Science.gov (United States)

    Manefield, Michael; Harris, Lachlan; Rice, Scott A.; de Nys, Rocky; Kjelleberg, Staffan

    2000-01-01

    Expression of luminescence in the Penaeus monodon pathogen Vibrio harveyi is regulated by an intercellular quorum sensing mechanism involving the synthesis and detection of two signaling molecules, one of which is N-hydroxy butanoyl-l-homoserine lactone and the other of which is uncharacterized. Indirect evidence has suggested that virulence, associated with a toxic extracellular protein, and luminescence in V. harveyi are coregulated. In this study the effects of an acylated homoserine lactone antagonist produced by the marine alga Delisea pulchra on luminescence and toxin production in a virulent strain of V. harveyi were analyzed. Luminescence and toxin production were both inhibited by the signal antagonist at concentrations that had no impact on growth. Toxin production was found to be prematurely induced in V. harveyi cultures incubated in a 10% conditioned medium. Additionally, a significant reduction in the toxicity of concentrated supernatant extracts from V. harveyi cultures incubated in the presence of the signal antagonist, as measured by in vivo toxicity assays in mice and prawns, was observed. These results suggest that intercellular signaling antagonists have potential utility in the control of V. harveyi prawn infections. PMID:10788385

  16. Luminescence of water or ice as a new detection method for magnetic monopoles

    Directory of Open Access Journals (Sweden)

    Pollmann Anna Obertacke

    2017-01-01

    We present analysis techniques to use luminescence in neutrino telescopes and discuss experimental setups to measure the light yield of luminescence for the particular conditions in neutrino detectors.

  17. Principal component analysis of normalized full spectrum mass spectrometry data in multiMS-toolbox: An effective tool to identify important factors for classification of different metabolic patterns and bacterial strains.

    Science.gov (United States)

    Cejnar, Pavel; Kuckova, Stepanka; Prochazka, Ales; Karamonova, Ludmila; Svobodova, Barbora

    2018-06-15

    Explorative statistical analysis of mass spectrometry data is still a time-consuming step. We analyzed critical factors for application of principal component analysis (PCA) in mass spectrometry and focused on two whole spectrum based normalization techniques and their application in the analysis of registered peak data and, in comparison, in full spectrum data analysis. We used this technique to identify different metabolic patterns in the bacterial culture of Cronobacter sakazakii, an important foodborne pathogen. Two software utilities, the ms-alone, a python-based utility for mass spectrometry data preprocessing and peak extraction, and the multiMS-toolbox, an R software tool for advanced peak registration and detailed explorative statistical analysis, were implemented. The bacterial culture of Cronobacter sakazakii was cultivated on Enterobacter sakazakii Isolation Agar, Blood Agar Base and Tryptone Soya Agar for 24 h and 48 h and applied by the smear method on an Autoflex speed MALDI-TOF mass spectrometer. For three tested cultivation media only two different metabolic patterns of Cronobacter sakazakii were identified using PCA applied on data normalized by two different normalization techniques. Results from matched peak data and subsequent detailed full spectrum analysis identified only two different metabolic patterns - a cultivation on Enterobacter sakazakii Isolation Agar showed significant differences to the cultivation on the other two tested media. The metabolic patterns for all tested cultivation media also proved the dependence on cultivation time. Both whole spectrum based normalization techniques together with the full spectrum PCA allow identification of important discriminative factors in experiments with several variable condition factors avoiding any problems with improper identification of peaks or emphasis on bellow threshold peak data. The amounts of processed data remain still manageable. Both implemented software utilities are available

  18. A polarized photoluminescence study of strained layer GaAs photocathodes

    International Nuclear Information System (INIS)

    Mair, R.A.

    1996-07-01

    Photoluminescence measurements have been made on a set of epitaxially grown strained GaAs photocathode structures. The photocathodes are designed to exhibit a strain-induced enhancement of the electron spin polarization obtainable by optical pumping with circularly polarized radiation of near band gap energy. For the case of non-strained GaAs, the degree of spin polarization is limited to 50% by crystal symmetry. Under an appropriate uniaxial compression or tension, however, the valence band structure near the gap minimum is modified such that a spin polarization of 100% is theoretically possible. A total of nine samples with biaxial compressive strains ranging from zero to ∼0.8% are studied. X-ray diffraction analysis, utilizing Bragg reflections, is used to determine the crystal lattice structure of the samples. Luminescence spectra and luminescence circular polarization data are obtained at room temperature, ∼78 K and ∼12 K. The degree of luminescence circular polarization is used as a relative measure of the photo-excited electron spin polarization. The room temperature luminescence circular polarization data is compared with the measured electron spin polarization when the samples are used as electron photo-emitters with a negative electron affinity surface preparation. The luminescence data is also analyzed in conjunction with the crystal structure data with the goal of understanding the strain dependent valence band structure, optical pumping characteristics and spin depolarization mechanisms of the photocathode structures. A simple model is used to describe the luminescence data, obtained for the set of samples. Within the assumptions of the model, the deformation potentials a, b and d for GaAs are determined. The measured values are a = -10.16±.21 eV, b = -2.00±.05 eV and d = -4.87±.29 eV. Good agreement with published values of the deformation potentials provides support for the model used to describe the data

  19. Identification and Characterization of Novel Biocontrol Bacterial

    Directory of Open Access Journals (Sweden)

    Young Cheol Kim

    2014-09-01

    Full Text Available Because bacterial isolates from only a few genera have been developed commercially as biopesticides, discovery and characterization of novel bacterial strains will be a key to market expansion. Our previous screen using plant bioassays identified 24 novel biocontrol isolates representing 12 different genera. In this study, we characterized the 3 isolates showing the best biocontrol activities. The isolates were Pantoea dispersa WCU35, Proteus myxofaciens WCU244, and Exiguobacterium acetylicum WCU292 based on 16S rRNA sequence analysis. The isolates showed differential production of extracellular enzymes, antimicrobial activity against various fungal or bacterial plant pathogens, and induced systemic resistance activity against tomato gray mold disease caused by Botrytis cinerea. E. acetylicum WCU292 lacked strong in vitro antimicrobial activity against plant pathogens, but induced systemic resistance against tomato gray mold disease. These results confirm that the trait of biological control is found in a wide variety of bacterial genera

  20. Agentes bacterianos enteropatogênicos em suínos de diferentes faixas etárias e perfil de resistência a antimicrobianos de cepas de Escherichia coli e Salmonella spp Enteropathogenic bacterial agents in pigs of different age groups and profile of resistance in strains of Escherichia coli and Salmonella spp. to antimicrobial agents

    Directory of Open Access Journals (Sweden)

    Álvaro Menin

    2008-09-01

    Full Text Available As enterites infecciosas bacterianas provocam severas perdas para a indústria suína em todo o mundo. Os objetivos deste trabalho foram determinar os agentes bacterianos, associados com a ocorrência de diarréia em suínos, em diferentes faixas etárias, no Estado de Santa Catarina, Brasil, e verificar o perfil de resistência das cepas de Escherichia coli e Salmonella spp, frente aos principais antimicrobianos utilizados em granjas de suínos. Os principais gêneros/espécies bacterianos diagnosticados foram Escherichia coli, Clostridium spp, Salmonella spp Brachyspira hyodysenteriae, Brachyspira pilosicoli e Lawsonia intracellularis. Os fatores de virulência de E. coli mais prevalentes na fase de maternidade foram F5 / (K99 20%, F6 / (987P 16,3%, F42 6,8% e F41 5,7%, já nas fases de creche e terminação, predominaram cepas com fimbrias F4 (K88 11,2% e 5,4%, respectivamente. Para E. coli os maiores índices de resistência foram encontrados para oxitetraciclina (94% e tetraciclina (89,5% e os menores índices de resistência para neomicina (55%, ceftiofur (57,4%. Quanto às amostras de Salmonella spp, estas apresentaram maior resistência à oxitetraciclina (77%, e à tetraciclina (42,1% e menor à gentamicina (3,5% e amoxicilina (4,8%.Infectious bacterial enteritis causes severe losses to the swine industry worldwide. The objective of this study was to determine the epidemiology of bacterial agents that are associated with the occurrence of diarrhea in pigs at different age groups, and to verify the profile of resistance of strains of Escherichia coli and Salmonella spp to the main antimicrobial agents. The main bacterial species diagnosed were Escherichia coli, Clostridium spp, Salmonella spp, Brachyspira hyodysenteriae, Brachyspira pilosicoli and Lawsonia intracellularis. The E. coli virulence factors of higher prevalence in preweaning piglets were F5 / (K99 20%, F6 / (987P 16.3%, F42 6.8% and F41 5.7%, whereas at the nursery and with

  1. Preparation of carbon quantum dots based high photostability luminescent membranes.

    Science.gov (United States)

    Zhao, Jinxing; Liu, Cui; Li, Yunchuan; Liang, Jiyuan; Liu, Jiyan; Qian, Tonghui; Ding, Jianjun; Cao, Yuan-Cheng

    2017-06-01

    Urethane acrylate (UA) was used to prepare carbon quantum dots (C-dots) luminescent membranes and the resultants were examined with FT-IR, mechanical strength, scanning electron microscope (SEM) and quantum yields (QYs). FT-IR results showed the polyurethane acrylate (PUA) prepolymer -C = C-vibration at 1101 cm -1 disappeared but there was strong vibration at1687cm -1 which was contributed from the-C = O groups in cross-linking PUA. Mechanical strength results showed that the different quantity of C-dots loadings and UV-curing time affect the strength. SEM observations on the cross-sections of the membranes are uniform and have no structural defects, which prove that the C-dots are compatible with the water-soluble PUA resin. The C-dot loading was increased from 0 to 1 g, the maximum tensile stress was nearly 2.67 MPa, but the tensile strain was decreased from 23.4% to 15.1% and 7.2% respectively. QYs results showed that the C-dots in the membrane were stable after 120 h continuous irradiation. Therefore, the C-dots photoluminescent film is the promising material for the flexible devices in the future applications. Copyright © 2016 John Wiley & Sons, Ltd.

  2. The uncultured luminous symbiont of Anomalops katoptron (Beryciformes: Anomalopidae) represents a new bacterial genus.

    Science.gov (United States)

    Hendry, Tory A; Dunlap, Paul V

    2011-12-01

    Flashlight fishes (Beryciformes: Anomalopidae) harbor luminous symbiotic bacteria in subocular light organs and use the bacterial light for predator avoidance, feeding, and communication. Despite many attempts anomalopid symbionts have not been brought into laboratory culture, which has restricted progress in understanding their phylogenetic relationships with other luminous bacteria, identification of the genes of their luminescence system, as well as the nature of their symbiotic interactions with their fish hosts. To begin addressing these issues, we used culture-independent analysis of the bacteria symbiotic with the anomalopid fish, Anomalops katoptron, to characterize the phylogeny of the bacteria and to identify the genes of their luminescence system including those involved in the regulation of luminescence. Analysis of the 16S rRNA, atpA, gapA, gyrB, pyrH, recA, rpoA, and topA genes resolved the A. katoptron symbionts as a clade nested within and deeply divergent from other members of Vibrionaceae. The bacterial luminescence (lux) genes were identified as a contiguous set (luxCDABEG), as found for the lux operons of other luminous bacteria. Phylogenetic analysis based on the lux genes confirmed the housekeeping gene phylogenetic placement. Furthermore, genes flanking the lux operon in the A. katoptron symbionts differed from those flanking lux operons of other genera of luminous bacteria. We therefore propose the candidate name Candidatus Photodesmus (Greek: photo = light, desmus = servant) katoptron for the species of bacteria symbiotic with A. katoptron. Results of a preliminary genomic analysis for genes regulating luminescence in other bacteria identified only a Vibrio harveyi-type luxR gene. These results suggest that expression of the luminescence system might be continuous in P. katoptron. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Oral bacterial DNA findings in pericardial fluid

    Directory of Open Access Journals (Sweden)

    Anne-Mari Louhelainen

    2014-11-01

    Full Text Available Background: We recently reported that large amounts of oral bacterial DNA can be found in thrombus aspirates of myocardial infarction patients. Some case reports describe bacterial findings in pericardial fluid, mostly done with conventional culturing and a few with PCR; in purulent pericarditis, nevertheless, bacterial PCR has not been used as a diagnostic method before. Objective: To find out whether bacterial DNA can be measured in the pericardial fluid and if it correlates with pathologic–anatomic findings linked to cardiovascular diseases. Methods: Twenty-two pericardial aspirates were collected aseptically prior to forensic autopsy at Tampere University Hospital during 2009–2010. Of the autopsies, 10 (45.5% were free of coronary artery disease (CAD, 7 (31.8% had mild and 5 (22.7% had severe CAD. Bacterial DNA amounts were determined using real-time quantitative PCR with specific primers and probes for all bacterial strains associated with endodontic disease (Streptococcus mitis group, Streptococcus anginosus group, Staphylococcus aureus/Staphylococcus epidermidis, Prevotella intermedia, Parvimonas micra and periodontal disease (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Fusobacterium nucleatus, and Dialister pneumosintes. Results: Of 22 cases, 14 (63.6% were positive for endodontic and 8 (36.4% for periodontal-disease-associated bacteria. Only one case was positive for bacterial culturing. There was a statistically significant association between the relative amount of bacterial DNA in the pericardial fluid and the severity of CAD (p=0.035. Conclusions: Oral bacterial DNA was detectable in pericardial fluid and an association between the severity of CAD and the total amount of bacterial DNA in pericardial fluid was found, suggesting that this kind of measurement might be useful for clinical purposes.

  4. Efecto de la inoculación de la cepa Sphingomonas paucimobilis 20006FA sobre la composición de un consorcio bacteriano degradador de fenantreno Effect of the inoculant strain Sphingomonas paucimobilis 20006FA on the bacterial composition of a phenanthrene-degrading consortium

    Directory of Open Access Journals (Sweden)

    L. Madueño

    2009-06-01

    Full Text Available Se estudió el efecto de la inoculación con la cepa Sphingomonas paucimobilis 20006FA sobre la composición bacteriana de un consorcio degradador de fenantreno en cultivos discontinuos (batch con 8 repiques sucesivos. El consorcio original se obtuvo a partir de un suelo prístino. A los fines del estudio, se obtuvieron y mantuvieron dos consorcios: uno inoculado (F200+I y otro sin inocular (F200. Se estudió la diversidad bacteriana de los consorcios mediante el análisis de microorganismos cultivables (por caracterización fenotípica y genotípica y totales (por PCR-DGGE. A lo largo de los repiques sucesivos pudo observarse en ambos consorcios una tendencia a la pérdida de la capacidad degradadora de fenantreno, acompañada por una disminución de la diversidad bacteriana. Si bien la inoculación no produjo cambios significativos en la capacidad degradadora de fenantreno de los consorcios (29,9% para F200 y 27,6% para F200+I hacia el tercer repique, sí produjo cambios en la composición bacteriana, ya que los perfiles de DGGE revelaron una dinámica estructural diferente en el consorcio inoculado. En ambos consorcios se pudo observar la presencia de una banda intensa posicionada a la misma altura que el ADN del inóculo en el gel de DGGE; sin embargo, los cultivos aislados de los consorcios que presentaban idéntica posición de banda en el perfil PCR-DGGE que la cepa S. paucimobilis 20006FA mostraron baja similitud con la cepa inoculada mediante la técnica de RAPD.The effect of the inoculant strain Sphingomonas paucimobilis 20006FA on the bacterial composition of a phenanthrene-degrading consortium obtained from a pristine soil in sequencing batch cultures was studied. Inoculated (F200+I and non-inoculated (F200 phenanthrene-degrading consortia, were obtained. Bacterial diversity of consortia was studied at cultivable (phenotype and genotype characterization and non-cultivable (PCR-DGGE levels. During the successive cultures, a loss in

  5. Bacterial diversity in agricultural soils during litter decomposition

    NARCIS (Netherlands)

    Dilly, O.; Bloem, J.; Vos, A.; Munch, J.C.

    2004-01-01

    Denaturing gradient gel electrophoresis (DGGE) of amplified fragments of genes coding for 16S rRNA was used to study the development of bacterial communities during decomposition of crop residues in agricultural soils. Ten strains were tested, and eight of these strains produced a single band.

  6. Luminescent properties of terbium complex with phenylanthranilic acid

    International Nuclear Information System (INIS)

    Alakaeva, L.A.; Kalazhokova, I.A.; Naurzhanova, F.Kh.

    1990-01-01

    Existence of terbium luminescence reaction in complex with phenanthranilic acid (FAA) is ascertained. The optimal conditions of terbium complexing with FAA are found. The ratio of components in the complex is 1:1. The influence of foreign rare earth in terbium luminescence intensity in complex with FAA is studied

  7. Luminescence properties of some food dye-stuffs

    International Nuclear Information System (INIS)

    Astanov, S.Kh.; Muminova, Z.A.; Urunov, R.G.

    2004-01-01

    The luminescence properties of the natural food dye-stuffs and vitamins in temperature range of 300-5.2 K are studied. On the basis of experimental data on quantum yields of the fluorescence, trans-cis-isomerization and luminescence of the molecular oxygen the main ways of the inactivation of electronic excitations in researching compounds have been defined. (author)

  8. Doped luminescent materials and particle discrimination using same

    Science.gov (United States)

    Doty, F. Patrick; Allendorf, Mark D; Feng, Patrick L

    2014-10-07

    Doped luminescent materials are provided for converting excited triplet states to radiative hybrid states. The doped materials may be used to conduct pulse shape discrimination (PSD) using luminescence generated by harvested excited triplet states. The doped materials may also be used to detect particles using spectral shape discrimination (SSD).

  9. Integrated light in direct excitation and energy transfer luminescence

    OpenAIRE

    Chimczak, Eugeniusz

    2007-01-01

    Integrated light in direct excitation and energy transfer luminescence has been investigated. In the investigations reported here, monomolecular centers were taken into account. It was found that the integrated light is equal to the product of generation rate and time of duration of excitation pulse for both direct excitation and energy transfer luminescence.

  10. Luminescence imaging using radionuclides: a potential application in molecular imaging

    International Nuclear Information System (INIS)

    Park, Jeong Chan; Il An, Gwang; Park, Se-Il; Oh, Jungmin; Kim, Hong Joo; Su Ha, Yeong; Wang, Eun Kyung; Min Kim, Kyeong; Kim, Jung Young; Lee, Jaetae; Welch, Michael J.; Yoo, Jeongsoo

    2011-01-01

    Introduction: Nuclear and optical imaging are complementary in many aspects and there would be many advantages when optical imaging probes are prepared using radionuclides rather than classic fluorophores, and when nuclear and optical dual images are obtained using single imaging probe. Methods: The luminescence intensities of various radionuclides having different decay modes have been assayed using luminescence imaging and in vitro luminometer. Radioiodinated Herceptin was injected into a tumor-bearing mouse, and luminescence and microPET images were obtained. The plant dipped in [ 32 P]phosphate solution was scanned in luminescence mode. Radio-TLC plate was also imaged in the same imaging mode. Results: Radionuclides emitting high energy β + /β - particles showed higher luminescence signals. NIH3T6.7 tumors were detected in both optical and nuclear imaging. The uptake of [ 32 P]phosphate in plant was easily followed by luminescence imaging. Radio-TLC plate was visualized and radiochemical purity was quantified using luminescence imaging. Conclusion: Many radionuclides with high energetic β + or β - particles during decay were found to be imaged in luminescence mode due mainly to Cerenkov radiation. 'Cerenkov imaging' provides a new optical imaging platform and an invaluable bridge between optical and nuclear imaging. New optical imaging probes could be easily prepared using well-established radioiodination methods. Cerenkov imaging will have more applications in the research field of plant science and autoradiography.

  11. Identification of resistance and virulence factors in an epidemic Enterobacter hormaechei outbreak strain

    NARCIS (Netherlands)

    Paauw, A.; Caspers, M.P.M.; Leverstein-van Hall, M.A.; Schuren, F.H.J.; Montijn, R.C.; Verhoef, J.; Fluit, A.C.

    2009-01-01

    Bacterial strains differ in their ability to cause hospital outbreaks. Using comparative genomic hybridization, Enterobacter cloacae complex isolates were studied to identify genetic markers specific for Enterobacter cloacae complex outbreak strains. No outbreak-specific genes were found that were

  12. Identification of Methyl Halide-Utilizing Genes in the Methyl Bromide-Utilizing Bacterial Strain IMB-1 Suggests a High Degree of Conservation of Methyl Halide-Specific Genes in Gram-Negative Bacteria

    Science.gov (United States)

    Woodall, C.A.; Warner, K.L.; Oremland, R.S.; Murrell, J.C.; McDonald, I.R.

    2001-01-01

    Strain IMB-1, an aerobic methylotrophic member of the alpha subgroup of the Proteobacteria, can grow with methyl bromide as a sole carbon and energy source. A single cmu gene cluster was identified in IMB-1 that contained six open reading frames: cmuC, cmuA, orf146, paaE, hutI, and partial metF. CmuA from IMB-1 has high sequence homology to the methyltransferase CmuA from Methylobacterium chloromethanicum and Hyphomicrobium chloromethanicum and contains a C-terminal corrinoid-binding motif and an N-terminal methyl-transferase motif. However, cmuB, identified in M. chloromethanicum and H. chloromethanicum, was not detected in IMB-1.

  13. Probing bacterial adhesion at the single-cell level

    DEFF Research Database (Denmark)

    Zeng, Guanghong; Müller, Torsten; Meyer, Rikke Louise

    be considered. We have developed a simple and versatile method to make single-cell bacterial probes for measuring single cell adhesion by force spectroscopy using atomic force microscopy (AFM). A single-cell probe was readily made by picking up a bacterial cell from a glass surface by approaching a tipless AFM...... cantilever coated with the commercial cell adhesive CellTakTM. We applied the method to study adhesion of living cells to abiotic surfaces at the single-cell level. Immobilisation of single bacterial cells to the cantilever was stable for several hours, and viability was confirmed by Live/Dead staining...... on the adhesion force, we explored the bond formation and adhesive strength of four different bacterial strains towards three abiotic substrates with variable hydrophobicity and surface roughness. The adhesion force and final rupture length were dependent on bacterial strains, surfaces properties, and time...

  14. Luminescence spectroscopy with synchrotron radiation: History, highlights, future

    International Nuclear Information System (INIS)

    Zimmerer, Georg

    2006-01-01

    Luminescence spectroscopy and the investigation of dynamical processes with synchrotron radiation (SR) started about 35 years ago in nearly all SR laboratories existing at that time. In the present paper, the pioneering experiments are particularly emphasized. The exciting development is illustrated presenting highlights for the whole period from the beginning to the present day. The highlights are taken from fields like exciton self-trapping, inelastic electron-electron scattering, optically stimulated desorption, cross luminescence, or probing of cluster properties with luminescence spectroscopic methods. More technological aspects play a role in present day's experiments, like quantum cutting in rare-earth-doped insulators. Promising two-photon excitation and light amplification experiments with SR will be included, as well as the first results obtained in a luminescence experiment with selective Vaccum ultraviolet-free electron laser excitation. Finally, a few ideas concerning the future development of luminescence spectroscopy with SR will be sketched

  15. Magnetic-luminescent spherical particles synthesized by ultrasonic spray pyrolysis

    International Nuclear Information System (INIS)

    Michel, Norma L; Hirata, Gustavo A; Flores, Dora L

    2015-01-01

    The combination of magnetic and luminescent properties in a single particle system, opens-up a wide range of potential applications in biotechnology and biomedicine. In this work, we performed the synthesis of magnetic-luminescent Gd 2 O 3 :Eu 3+ @Fe 2 O 3 particles by ultrasonic spray pyrolysis performed in a tubular furnace. In order to achieve the composite formation, commercial superparamagnetic Fe 3 O 4 nanoparticles were coated with a luminescent Eu 3+ -doped Gd 2 O 3 shell in a low-cost one-step process. The spray pyrolysis method yields deagglomerated spherical shape magneto/luminescent particles. The photoluminescence spectra under UV excitation (λ Exc = 265 nm) of the magnetic Gd 2 O 3 :Eu 3+ @Fe 2 O 3 compound showed the characteristic red emission of Eu 3+ (λ Em = 612 nm). This magneto/luminescent system will find applications in biomedicine and biotechnology. (paper)

  16. Factors influencing bacterial adhesion to contact lenses.

    Science.gov (United States)

    Dutta, Debarun; Cole, Nerida; Willcox, Mark

    2012-01-01

    The process of any contact lens related keratitis generally starts with the adhesion of opportunistic pathogens to contact lens surface. This article focuses on identifying the factors which have been reported to affect bacterial adhesion to contact lenses. Adhesion to lenses differs between various genera/species/strains of bacteria. Pseudomonas aeruginosa, which is the predominant causative organism, adheres in the highest numbers to both hydrogel and silicone hydrogel lenses in vitro. The adhesion of this strain reaches maximum numbers within 1h in most in vitro studies and a biofilm has generally formed within 24 h of cells adhering to the lens surface. Physical and chemical properties of contact lens material affect bacterial adhesion. The water content of hydroxyethylmethacrylate (HEMA)-based lenses and their iconicity affect the ability of bacteria to adhere. The higher hydrophobicity of silicone hydrogel lenses compared to HEMA-based lenses has been implicated in the higher numbers of bacteria that can adhere to their surfaces. Lens wear has different effects on bacterial adhesion, partly due to differences between wearers, responses of bacterial strains and the ability of certain tear film proteins when bound to a lens surface to kill certain types of bacteria.

  17. Synthesis of high luminescent carbon nanoparticles

    Science.gov (United States)

    Gvozdyuk, Alina A.; Petrova, Polina S.; Goryacheva, Irina Y.; Sukhorukov, Gleb B.

    2017-03-01

    In this article we report an effective and simple method for synthesis of high luminescent carbon nanodots (CDs). In our work as a carbon source sodium dextran sulfate (DS) was used because it is harmless, its analogs are used in medicine as antithrombotic compounds and blood substitutes after hemorrhage. was used as a substrate We investigated the influence of temperature parameters of hydrothermal synthesis on the photoluminescence (PL) intensity and position of emission maxima. We discovered that the PL intensity can be tuned by changing of synthesis temperature and CD concentration.

  18. Circularly polarized luminescence of syndiotactic polystyrene

    Science.gov (United States)

    Rizzo, Paola; Abbate, Sergio; Longhi, Giovanna; Guerra, Gaetano

    2017-11-01

    Syndiotactic polystyrene (s-PS) films, when crystallized from the amorphous state by temporary sorption of non-racemic guest molecules (like carvone) not only exhibit unusually high optical activity, both in the UV-Visible and Infrared ranges, but also present circularly polarized luminescence (CPL) with high dissymmetry ratios (g = ΔI/I values in the range 0.02-0.03). Experimental evidences provide support, rather than to the usual molecular circular dichroism, to a supramolecular chiral optical response being extrinsic to the site of photon absorption and emission, possibly associated with a helical morphology of s-PS crystallites.

  19. Luminescent properties of praseodymium in some fluorides

    International Nuclear Information System (INIS)

    Potapov, A.S.; Rodnyj, P.A.; Mikhrin, S.B.; Magunov, I.R.

    2005-01-01

    Influence of diverse factors on efficiency of the Pr 3+ cascade emission in BaF 2 : Pr and SrAlF 5 : Pr. The effect of the environment of the luminescence center on the mutual position of the lowest 5d and the 4f level 1 S 0 of Pr 3+ ion is considered. PrF 3 clustering in BaF 2 is observed at a high praseodymium concentration. The promising potential of magnesium as a charge compensator for praseodymium in SrAlF 5 is demonstrated [ru

  20. Luminescent solar concentrators with fiber geometry.

    Science.gov (United States)

    Edelenbosch, Oreane Y; Fisher, Martyn; Patrignani, Luca; van Sark, Wilfried G J H M; Chatten, Amanda J

    2013-05-06

    The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear with fibre length. A 1 m long, radius 1 mm, fibre LSC doped with Lumogen Red 305 is predicted to concentrate the AM1.5 g spectrum up to 1100 nm at normal incidence by ~35 x. The collection efficiency under diffuse and direct irradiance in London has been analysed showing that, even under clear sky conditions, in winter the diffuse contribution equals the direct.

  1. Research Update: Luminescence in lead halide perovskites

    Directory of Open Access Journals (Sweden)

    Ajay Ram Srimath Kandada

    2016-09-01

    Full Text Available Efficiency and dynamics of radiative recombination of carriers are crucial figures of merit for optoelectronic materials. Following the recent success of lead halide perovskites in efficient photovoltaic and light emitting technologies, here we review some of the noted literature on the luminescence of this emerging class of materials. After outlining the theoretical formalism that is currently used to explain the carrier recombination dynamics, we review a few significant works which use photoluminescence as a tool to understand and optimize the operation of perovskite based optoelectronic devices.

  2. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... to include the effects of the environmental dose rate. By fitting the model to the dose-depth variation from a single clast, four events (two light exposures of different durations each followed by a burial period) in the history of a single cobble are identified and quantified. However, the use of model...

  3. Isolation and characterization of bacterial endophytes of Curcuma longa L.

    OpenAIRE

    Kumar, Ajay; Singh, Ritu; Yadav, Akhilesh; Giri, D. D.; Singh, P. K.; Pandey, Kapil D.

    2016-01-01

    Fourteen endophytic bacterial isolates were isolated from the rhizome of Curcuma longa L. were characterized on the basis of morphology, biochemical characteristics and 16S rRNA gene sequence analysis. The isolates were identified to six strains namely Bacillus cereus (ECL1), Bacillus thuringiensis (ECL2), Bacillus sp. (ECL3), Bacillus pumilis (ECL4), Pseudomonas putida (ECL5), and Clavibacter michiganensis (ECL6). All the strains produced IAA and solubilized phosphate and only two strains pr...

  4. Luminescence at the end of the tunnelling - Investigating charge transfer mechanisms and luminescence dating methods for feldspar minerals

    NARCIS (Netherlands)

    Kars, R.H.

    2014-01-01

    This thesis comprises analyses of mineral physics with an application in geology and archeology. The thesis contributes to the development of feldspar luminescence dating methods in order to extend the applicable age range of feldspar luminescence dating in the Quaternary (last 2.6 Ma). The research

  5. High prevalence of biofilm synergy among bacterial soil isolates in cocultures indicates bacterial interspecific cooperation

    DEFF Research Database (Denmark)

    Ren, Dawei; Madsen, Jonas Stenløkke; Sørensen, Søren Johannes

    2015-01-01

    of single-species biofilms, indicating that all the individual strains benefit from inclusion in the multispecies community. Our results show a high prevalence of synergy in biofilm formation in multispecies consortia isolated from a natural bacterial habitat and suggest that interspecific cooperation...

  6. Mechanism for iron control of the Vibrio fischeri luminescence system: involvement of cyclic AMP and cyclic AMP receptor protein and modulation of DNA level.

    Science.gov (United States)

    Dunlap, P V

    1992-07-01

    Iron controls luminescence in Vibrio fischeri by an indirect but undefined mechanism. To gain insight into that mechanism, the involvement of cyclic AMP (cAMP) and cAMP receptor protein (CRP) and of modulation of DNA levels in iron control of luminescence were examined in V. fischeri and in Escherichia coli containing the cloned V. fischeri lux genes on plasmids. For V. fischeri and E. coli adenylate cyclase (cya) and CRP (crp) mutants containing intact lux genes (luxR luxICDABEG), presence of the iron chelator ethylenediamine-di(o-hydroxyphenyl acetic acid) (EDDHA) increased expression of the luminescence system like in the parent strains only in the cya mutants in the presence of added cAMP. In the E. coli strains containing a plasmid with a Mu dl(lacZ) fusion in luxR, levels of beta-galactosidase activity (expression from the luxR promoter) and luciferase activity (expression from the lux operon promoter) were both 2-3-fold higher in the presence of EDDHA in the parent strain, and for the mutants this response to EDDHA was observed only in the cya mutant in the presence of added cAMP. Therefore, cAMP and CRP are required for the iron restriction effect on luminescence, and their involvement in iron control apparently is distinct from the known differential control of transcription from the luxR and luxICDABEG promoters by cAMP-CRP. Furthermore, plasmid and chromosomal DNA levels were higher in E. coli and V. fischeri in the presence of EDDHA. The higher DNA levels correlated with an increase in expression of chromosomally encoded beta-galactosidase in E. coli and with a higher level of autoinducer in cultures of V. fischeri. These results implicate cAMP-CRP and modulation of DNA levels in the mechanism of iron control of the V. fischeri luminescence system.

  7. Seismic Moment and Recurrence using Luminescence Dating Techniques: Characterizing brittle fault zone materials suitable for luminescence dating

    Science.gov (United States)

    Tsakalos, E.; Lin, A.; Bassiakos, Y.; Kazantzaki, M.; Filippaki, E.

    2017-12-01

    During a seismic-geodynamic process, frictional heating and pressure are generated on sediments fragments resulting in deformation and alteration of minerals contained in them. The luminescence signal enclosed in minerals crystal lattice can be affected and even zeroed during such an event. This has been breakthrough in geochronological studies as it could be utilized as a chronometer for the previous seismic activity of a tectonically active area. Although the employment of luminescence dating has in some cases been successfully described, a comprehensive study outlining and defining protocols for routine luminescence dating applied to neotectonic studies has not been forthcoming. This study is the experimental investigation, recording and parameterization of the effects of tectonic phenomena on minerals luminescence signal and the development of detailed protocols for the standardization of the luminescence methodology for directly dating deformed geological formations, so that the long-term temporal behaviour of seismically active faults could be reasonably understood and modeled. This will be achieved by: a) identifying and proposing brittle fault zone materials suitable for luminescence dating using petrological, mineralogical and chemical analyses and b) investigating the "zeroing" potential of the luminescence signal of minerals contained in fault zone materials by employing experimental simulations of tectonic processes in the laboratory, combined with luminescence measurements on samples collected from real fault zones. For this to be achieved, a number of samples collected from four faults of four different geographical regions will be used. This preliminary-first step of the study presents the microstructural, and mineralogical analyses for the characterization of brittle fault zone materials that contain suitable minerals for luminescence dating (e.g., quartz and feldspar). The results showed that the collected samples are seismically deformed fault

  8. Luminescence optically stimulated: theory and applications

    International Nuclear Information System (INIS)

    Rivera M, T.; Azorin N, J.

    2002-01-01

    The thermally stimulated luminescence (Tl) has occupied an important place in the Solid state physics (FES) by the flexibility of the phenomena, mainly for its applications in the fields of Radiation Physics (FR) and Medical Physics (MF). The reason of this phenomena lies in the fact of the electrons release by the action of heat. Under that same reason, it can be used the action of another stimulant agent for releasing the trapped electrons in the metastable states (EM), this agent is the light which has the same effect that the heat, giving as result the production of light photons at using light in the visible spectra, of different wavelength that the excitation light. This phenomena is called Luminescence optically stimulated (LOE). The LOE has a great impact in the Solid State Physics (FES), dating and now in the use of the phenomena as a dosimetric method, alternate to the Tl, for its use in the ionizing and non-ionizing radiations fields. (Author)

  9. Nervous control of photophores in luminescent fishes.

    Science.gov (United States)

    Zaccone, Giacomo; Abelli, Luigi; Salpietro, Lorenza; Zaccone, Daniele; Macrì, Battesimo; Marino, Fabio

    2011-07-01

    Functional studies of the autonomic innervation in the photophores of luminescent fishes are scarce. The majority of studies have involved either the stimulation of isolated photophores or the modulatory effects of adrenaline-induced light emission. The fish skin is a highly complex organ that performs a wide variety of physiological processes and receives extensive nervous innervations. The latter includes autonomic nerve fibers of spinal sympathetic origin having a secretomotor function. More recent evidence indicates that neuropeptide-containing nerve fibers, such as those that express tachykinin and its NK1 receptor, neuropeptide Y, or nitric oxide, may also play an important role in the nervous control of photophores. There is no anatomical evidence that shows that nNOS positive (nitrergic) neurons form a population distinct from the secretomotor neurons with perikarya in the sympathetic ganglia. The distribution and function of the nitrergic nerves in the luminous cells, however, is less clear. It is likely that the chemical properties of the sympathetic postganglionic neurons in the ganglia of luminescent fishes are target-specific, such as observed in mammals. Copyright © 2010 Elsevier GmbH. All rights reserved.

  10. Eye-specification genes in the bacterial light organ of the bobtail squid Euprymna scolopes, and their expression in response to symbiont cues.

    Science.gov (United States)

    Peyer, Suzanne M; Pankey, M Sabrina; Oakley, Todd H; McFall-Ngai, Margaret J

    2014-02-01

    The squid Euprymna scolopes has evolved independent sets of tissues capable of light detection, including a complex eye and a photophore or 'light organ', which houses the luminous bacterial symbiont Vibrio fischeri. As the eye and light organ originate from different embryonic tissues, we examined whether the eye-specification genes, pax6, eya, six, and dac, are shared by these two organs, and if so, whether they are regulated in the light organ by symbiosis. We obtained sequences of the four genes with PCR, confirmed orthology with phylogenetic analysis, and determined that each was expressed in the eye and light organ. With in situ hybridization (ISH), we localized the gene transcripts in developing embryos, comparing the patterns of expression in the two organs. The four transcripts localized to similar tissues, including those associated with the visual system ∼1/4 into embryogenesis (Naef stage 18) and the light organ ∼3/4 into embryogenesis (Naef stage 26). We used ISH and quantitative real-time PCR to examine transcript expression and differential regulation in postembryonic light organs in response to the following colonization conditions: wild-type, luminescent V. fischeri; a mutant strain defective in light production; and as a control, no symbiont. In ISH experiments light organs showed down regulation of the pax6, eya, and six transcripts in response to wild-type V. fischeri. Mutant strains also induced down regulation of the pax6 and eya transcripts, but not of the six transcript. Thus, luminescence was required for down regulation of the six transcript. We discuss these results in the context of symbiont-induced light-organ development. Our study indicates that the eye-specification genes are expressed in light-interacting tissues independent of their embryonic origin and are capable of responding to bacterial cues. These results offer evidence for evolutionary tinkering or the recruitment of eye development genes for use in a light

  11. Zinc and nitrogen ornamented bluish white luminescent carbon dots for engrossing bacteriostatic activity and Fenton based bio-sensor.

    Science.gov (United States)

    Das, Poushali; Ganguly, Sayan; Bose, Madhuparna; Mondal, Subhadip; Choudhary, Sumita; Gangopadhyay, Subhashis; Das, Amit Kumar; Banerjee, Susanta; Das, Narayan Chandra

    2018-07-01

    Carbon dots with heteroatom co-doping associated with consummate luminescence features are of acute interest in diverse applications such as biomolecule markers, chemical sensing, photovoltaic, and trace element detection. Herein, we demonstrate a straightforward, highly efficient hydrothermal dehydration technique to synthesize zinc and nitrogen co-doped multifunctional carbon dots (N, Zn-CDs) with superior quantum yield (50.8%). The luminescence property of the carbon dots can be tuned by regulating precursor ratio and surface oxidation states in the carbon dots. A unique attribution of the as-prepared carbon dots is the high monodispersity and robust excitation-independent emission behavior that is stable in enormously reactive environment and over a wide range of pH. These N, Zn-CDs unveils captivating bacteriostatic activity against gram-negative bacteria Escherichia coli. Furthermore, the excellent luminescence properties of these carbon dots were applied as a platform of sensitive biosensor for the detection of hydrogen peroxide. Under optimized conditions, these N, Zn-CDs reveals high sensitivity over a broad range of concentrations with an ultra-low limit of detection (LOD) indicating their pronounced prospective as a fluorescent probe for chemical sensing. Overall, the experimental outcomes propose that these zero-dimensional nano-dots could be developed as bacteriostatic agents to control and prevent the persistence and spreading of bacterial infections and as a fluorescent probe for hydrogen peroxide detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Carbon and Hydrogen Stable Isotope Fractionation during Aerobic Bacterial Degradation of Aromatic Hydrocarbons†

    Science.gov (United States)

    Morasch, Barbara; Richnow, Hans H.; Schink, Bernhard; Vieth, Andrea; Meckenstock, Rainer U.

    2002-01-01

    13C/12C and D/H stable isotope fractionation during aerobic degradation was determined for Pseudomonas putida strain mt-2, Pseudomonas putida strain F1, Ralstonia pickettii strain PKO1, and Pseudomonas putida strain NCIB 9816 grown with toluene, xylenes, and naphthalene. Different types of initial reactions used by the respective bacterial strains could be linked with certain extents of stable isotope fractionation during substrate degradation. PMID:12324375

  13. Principal and secondary luminescence lifetime components in annealed natural quartz

    International Nuclear Information System (INIS)

    Chithambo, M.L.; Ogundare, F.O.; Feathers, J.

    2008-01-01

    Time-resolved luminescence spectra from quartz can be separated into components with distinct principal and secondary lifetimes depending on certain combinations of annealing and measurement temperature. The influence of annealing on properties of the lifetimes related to irradiation dose and temperature of measurement has been investigated in sedimentary quartz annealed at various temperatures up to 900 deg. C. Time-resolved luminescence for use in the analysis was pulse stimulated from samples at 470 nm between 20 and 200 deg. C. Luminescence lifetimes decrease with measurement temperature due to increasing thermal effect on the associated luminescence with an activation energy of thermal quenching equal to 0.68±0.01eV for the secondary lifetime but only qualitatively so for the principal lifetime component. Concerning the influence of annealing temperature, luminescence lifetimes measured at 20 deg. C are constant at about 33μs for annealing temperatures up to 600 0 C but decrease to about 29μs when the annealing temperature is increased to 900 deg. C. In addition, it was found that lifetime components in samples annealed at 800 deg. C are independent of radiation dose in the range 85-1340 Gy investigated. The dependence of lifetimes on both the annealing temperature and magnitude of radiation dose is described as being due to the increasing importance of a particular recombination centre in the luminescence emission process as a result of dynamic hole transfer between non-radiative and radiative luminescence centres

  14. Increasing lanthanide luminescence by use of the RETEL effect.

    Science.gov (United States)

    Leif, Robert C; Vallarino, Lidia M; Becker, Margie C; Yang, Sean

    2006-08-01

    Luminescent lanthanide complexes produce emissions with the narrowest-known width at half maximum; however, their significant use in cytometry required an increase in luminescence intensity. The companion review, Leif et al., Cytometry 2006;69A:767-778, described a new technique for the enhancement of lanthanide luminescence, the Resonance Energy Transfer Enhanced Luminescence (RETEL) effect, which increases luminescence and is compatible with standard slide microscopy. The luminescence of the europium ion macrocyclic complex, EuMac, was increased by employing the RETEL effect. After adding the nonluminescent gadolinium ion complex of the thenoyltrifluoroacetonate (TTFA) ligand or the sodium salt of TTFA in ethanol solution, the EuMac-labeled sample was allowed to dry. Both a conventional arc lamp and a time-gated UV LED served as light sources for microscopic imaging. The emission intensity was measured with a CCD camera. Multiple time-gated images were summed with special software to permit analysis and effective presentation of the final image. With the RETEL effect, the luminescence of the EuMac-streptavidin conjugate increased at least six-fold upon drying. Nuclei of apoptotic cells were stained with DAPI and tailed with 5BrdUrd to which a EuMac-anti-5BrdU conjugate was subsequently attached. Time-gated images showed the long-lived EuMac luminescence but did not show the short-lived DAPI fluorescence. Imaging of DNA-synthesizing cells with an arc lamp showed that both S phase and apoptotic cells were labeled, and that their labeling patterns were different. The images of the luminescent EuMac and fluorescent DAPI were combined to produce a color image on a white background. This combination of simple chemistry, instrumentation, and presentation should make possible the inexpensive use of the lanthanide macrocycles, Quantum Dyes, as molecular diagnostics for cytological and histopathological microscopic imaging. (c) 2006 International Society for Analytical

  15. Luminescence imaging of water during alpha particle irradiation

    Science.gov (United States)

    Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Toshito, Toshiyuki

    2016-05-01

    The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of 241Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

  16. Luminescence imaging of water during alpha particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Komori, Masataka; Koyama, Shuji [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center (Japan)

    2016-05-21

    The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of {sup 241}Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

  17. Oxide/polymer nanocomposites as new luminescent materials

    Science.gov (United States)

    Vollath, D.; Szabó, D. V.; Schlabach, S.

    2004-06-01

    It is demonstrated that nanocomposites, consisting of an electrically insulating oxide core and PMMA coating exhibit strong luminescence. This luminescence is connected to the interface, where PMMA is bond via a carboxylate bonding to the surface. In this case, luminescence is originated at the carbonyl group of the coating polymer. With decreasing particle size, this emission shows a blue shift, following a law inversely the ones found for quantum confinement systems. For semi-conducting oxides, such as ZnO, this interface related emission is found additionally to quantum confinement phenomena.

  18. Splitting of the luminescent excited state of the uranyl ion

    International Nuclear Information System (INIS)

    Flint, C.D.; Sharma, P.; Tanner, P.A.

    1982-01-01

    The luminescence spectra of some uranyl compounds has been studied. It has been proposed that the splitting of the luminescent excited state of the uranyl ion is due to a descent in symmetry experienced by the uranyl ion when it is placed in a crystal field. In recent years there has been developed a highly successful model of the electronic structure of the uranyl ion. In this paper the authors use this model to interpret the luminescence spectra of a variety of uranyl compounds

  19. NaCl samples for optical luminescence dosimetry

    International Nuclear Information System (INIS)

    Catli, S.

    2005-01-01

    Optically stimulated luminescence (OSL) have been used broadly for luminescence dosimetry and dating. In many cases, it has been pointed out that the decay of the OSL do not generally behave according to a simple exponential function. In this study the Infra-red stimulated luminescence (IRSL) intensity from NaCl samples were experimentally measured. The decay curves for this sample were fitted to some functions and it is in good agreement with the function y = α + b exp(-cx). The IRSL decay curves from NaCl using different β-doses have been obtained and investigated their dose response

  20. Chemisorptive luminescence on γ-irradiated magnesium oxide

    International Nuclear Information System (INIS)

    Breakspere, R.J.; Read, R.L.

    1976-01-01

    The intensity of a chemisorptive luminescence produced on MgO by oxygen at room temperature is increased by prior γ-irradiation of the MgO, under vacuum, before adsorption. This enhancement of the luminescence increases with radiation dose up to 1.9 x 10 6 rad and is attributed to the interaction between the F + sub (s) centres produced by the radiation and oxygen molecules arriving at the surface from the gas phase. In this work, the spectrum of the emitted luminescence could not be measured. (author)

  1. A luminescence imaging system based on a CCD camera

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.; Markey, B.G.

    1997-01-01

    Stimulated luminescence arising from naturally occurring minerals is likely to be spatially heterogeneous. Standard luminescence detection systems are unable to resolve this variability. Several research groups have attempted to use imaging photon detectors, or image intensifiers linked...... to photographic systems, in order to obtain spatially resolved data. However, the former option is extremely expensive and it is difficult to obtain quantitative data from the latter. This paper describes the use of a CCD camera for imaging both thermoluminescence and optically stimulated luminescence. The system...

  2. Determination of uranium by luminescent method (tablet variant)

    International Nuclear Information System (INIS)

    Sergeev, A.N.; Yufa, B.Ya.

    1985-01-01

    A new tablet variant of luminescent determination of uranium in rocks is developed. The analytical process includes the following operations: sample decomposition, uranium separation from luminescence quencher impurities, preparation of luminescent sample (tablet), photometry of the tablet. The method has two variants developed: the first one is characterized by a more hard decomposition, sample mass being 0.2 g; the second variant has a better detection limit (5x10 -6 %), the sample mass being 0.2-1 g. Procedures of the sample preparation for both variants of analysis are described

  3. Luminescence from potassium feldspars stimulated by infrared and green light

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.

    1993-01-01

    A series of experiments are reported which investigate stimulated luminescence from potassium feldspar. The aim is to provide a basic phenomenological description of the response of the material to stimulation by heat, infrared radiation (875 DELTA 80 nm) and a green light wavelength band from 5 15...... to 560 nm. Two conclusions are drawn: firstly it is suggested that the majority of the trapped charge responsible for the infrared stimulated luminescence signal does not give rise to a thermoluminescence signal, and secondly that a large traction of the two optically stimulated luminescence signals...

  4. Container Verification Using Optically Stimulated Luminescence

    International Nuclear Information System (INIS)

    Tanner, Jennifer E.; Miller, Steven D.; Conrady, Matthew M.; Simmons, Kevin L.; Tinker, Michael R.

    2008-01-01

    Containment verification is a high priority for safeguards containment and surveillance. Nuclear material containers, safeguards equipment cabinets, camera housings, and detector cable conduit are all vulnerable to tampering. Even with a high security seal on a lid or door, custom-built hinges and interfaces, and special colors and types of finishes, the surfaces of enclosures can be tampered with and any penetrations repaired and covered over. With today's technology, these repairs would not be detected during a simple visual inspection. Several suggested solutions have been to develop complicated networks of wires, fiber-optic cables, lasers or other sensors that line the inside of a container and alarm when the network is disturbed. This results in an active system with real time evidence of tampering but is probably not practical for most safeguards applications. A more practical solution would be to use a passive approach where an additional security feature was added to surfaces which would consist of a special coating or paint applied to the container or enclosure. One type of coating would incorporate optically stimulated luminescent (OSL) material. OSL materials are phosphors that luminesce in proportion to the ionizing radiation dose when stimulated with the appropriate optical wavelengths. The OSL fluoresces at a very specific wavelength when illuminated at another, very specific wavelength. The presence of the pre-irradiated OSL material in the coating is confirmed using a device that interrogates the surface of the enclosure using the appropriate optical wavelength and then reads the resulting luminescence. The presence of the OSL indicates that the integrity of the surface is intact. The coating itself could be transparent which would allow the appearance of the container to remain unchanged or the OSL material could be incorporated into certain paints or epoxies used on various types of containers. The coating could be applied during manufacturing

  5. Detection of food irradiation with luminescence methods

    International Nuclear Information System (INIS)

    Anderle, H.

    1997-06-01

    Food irradiation is applied as method for the preservation of foods, the prevention of food spoilage and the inhibition of food-borne pathogens. Doses exceeding 10 kGy (10 kJ/kg) are not recommended by the WHO. The different legislation requires methods for the detection and the closimetry of irradiated foods. Among the physical methods based on the radiation-induced changes in inorganic, nonhygroscopic crystalline solids are thermoluminescence (TL), photostimulated luminescence (PSL) and lyoluminescence (LL) measurement. The luminescence methods were tested on natural minerals. Pure quartz, feldspars, calcite, aragonite and dolomite of known origin were irradiated, read out and analyzed to determine the influence of luminescence-activators and deactivators. Carbonate minerals show an orange-red TL easily detectable by blue-sensitive photomultiplier tubes. TIL-inactive carbonate samples may be identified by a lyoluminescence method using the reaction of trapped irradiation-generated charge carriers with the solvent during crystal-lattice breakup. The fine-ground mineral is dissolved in an alkaline complexing agent/chemiluminescence sensitizer/chemiluminescence catalyst (EDTA/luminol/hemin) reagent mixture. The TL and PSL of quartz is too weak to contribute a significant part for the corresponding signals in polymineral dust. Alkali and soda feldspar show intense TL and PSL. The temperature maxima in the TL glow curves allow a clear distinction. PSL does not give this additional information, it suffers from bleaching by ambient light and requires light-protection. Grain disinfestated with low irradiation doses (500 Gy) may not identified by both TL and PSL measurement. The natural TL of feldspar particles may be overlap with the irradiation-induced TL of other minerals. As a routine method, irradiated spices are identified with TL measurement. The dust particles have to be enriched by heavy-liquid flotation and centrifugation. The PSL method allows a clear

  6. Morphological characterization of several strains of the rice-pathogenic bacterium Burkholderia glumae in North Sumatra

    Science.gov (United States)

    Hasibuan, M.; Safni, I.; Lisnawita; Lubis, K.

    2018-02-01

    Burkholderia glumae is a quarantine seed-borne bacterial pathogen causing panicle blight disease on rice. This pathogen has been detected in some locations in Java, and recently, farmers in North Sumatra have reported rice yield loss with symptoms similar with those on rice infeced by the rice-pathogenic bacterium B. glumae. This research was aimed to isolate several bacterial strains from several rice varieties in various locations in North Sumatra and characterize the morphology of the strains to detect and identify the unknown bacterial strains presumably B. glumae. Several rice seed varieties were collected from Medan and Deli Serdang Districts. The seed samples were extracted, isolated and purified, then grown in semi-selective media PPGA. The morphological characteristics of the bacterial strains were determined including Gram staining, bacterial colony’s and bacterial cell’s morphology. The results showed that of eleven strains isolated, two strains were Gram negative and nine strains were Gram positive. On the basis of colony morphology, all strains had circular form, flat elevation and cream colour while the colony margin varied, i.e. entire and undulate. Most strains had bacillus/rod shape (8 strains) and only 3 strains were coccus.

  7. Bacterial endophytes enhance competition by invasive plants.

    Science.gov (United States)

    Rout, Marnie E; Chrzanowski, Thomas H; Westlie, Tara K; DeLuca, Thomas H; Callaway, Ragan M; Holben, William E

    2013-09-01

    Invasive plants can alter soil microbial communities and profoundly alter ecosystem processes. In the invasive grass Sorghum halepense, these disruptions are consequences of rhizome-associated bacterial endophytes. We describe the effects of N2-fixing bacterial strains from S. halepense (Rout and Chrzanowski, 2009) on plant growth and show that bacteria interact with the plant to alter soil nutrient cycles, enabling persistence of the invasive. • We assessed fluxes in soil nutrients for ∼4 yr across a site invaded by S. halepense. We assayed the N2-fixing bacteria in vitro for phosphate solubilization, iron chelation, and production of the plant-growth hormone indole-3-acetic acid (IAA). We assessed the plant's ability to recruit bacterial partners from substrates and vertically transmit endophytes to seeds and used an antibiotic approach to inhibit bacterial activity in planta and assess microbial contributions to plant growth. • We found persistent alterations to eight biogeochemical cycles (including nitrogen, phosphorus, and iron) in soils invaded by S. halepense. In this context, three bacterial isolates solubilized phosphate, and all produced iron siderophores and IAA in vitro. In growth chamber experiments, bacteria were transmitted vertically, and molecular analysis of bacterial community fingerprints from rhizomes indicated that endophytes are also horizontally recruited. Inhibiting bacterial activity with antibiotics resulted in significant declines in plant growth rate and biomass, with pronounced rhizome reductions. • This work suggests a major role of endophytes on growth and resource allocation of an invasive plant. Indeed, bacterial isolate physiology is correlated with invader effects on biogeochemical cycles of nitrogen, phosphate, and iron.

  8. Luminescence and the light emitting diode the basics and technology of leds and the luminescence properties of the materials

    CERN Document Server

    Williams, E W; Pamplin, BR

    2013-01-01

    Luminescence and the Light Emitting Diode: The Basics and Technology of LEDS and the Luminescence Properties of the Materials focuses on the basic physics and technology of light emitting diodes (LEDS) and pn junction lasers as well as their luminescence properties. Optical processes in semiconductors and the useful devices which can be made are discussed. Comprised of 10 chapters, this book begins with an introduction to the crystal structure and growth, as well as the optical and electrical properties of LED materials. The detailed fabrication of the LED is then considered, along with the lu

  9. Rapid Identification of Bacterial Virulence Factors

    Science.gov (United States)

    2014-04-15

    protein sorting and transport. F/’/wyi-deletion mutants had decreased invasiveness of HeLa cells when compared to their parental strain, and it has...mileux. Bacteria with intracellular life styles and have reductive genomes often have many different ABC transporters. This is certainly the case in...34 Microbiology 151:2975-2986. Newman , R.M., P. Salunkhe, A. Godzik, J.C. Reed. 2006. Identification and Characterization of a Novel Bacterial

  10. Factors influencing bacterial adhesion to contact lenses

    OpenAIRE

    Dutta, Debarun; Cole, Nerida; Willcox, Mark

    2012-01-01

    The process of any contact lens related keratitis generally starts with the adhesion of opportunistic pathogens to contact lens surface. This article focuses on identifying the factors which have been reported to affect bacterial adhesion to contact lenses. Adhesion to lenses differs between various genera/species/strains of bacteria. Pseudomonas aeruginosa, which is the predominant causative organism, adheres in the highest numbers to both hydrogel and silicone hydrogel lenses in vitro. The ...

  11. Detection of irradiated food using photostimulated luminescence

    International Nuclear Information System (INIS)

    Malec-Czechowska, K.; Stachowicz, W.

    2005-01-01

    Detection of irradiated spices, dried mushrooms and flavour blends using photostimulated luminescence (PSL) is presented. PSL measurements were carried out as described in standard PN-EN 13751. A lower threshold (T 1 700 counts/60s) and an upper threshold (T 2 = 5000 counts/60s) were used to classify the sample. PSL intensities below the threshold were classified as from non-irradiated samples and PSL signals above the upper threshold were regarded from irradiated samples. Signal levels between the two thresholds were classified as intermediate, showing that further investigations are necessary. The PSL tests were carried out at Institute Nutritional Physiology, Federal Research Centre for Nutrition in Karlsruhe with a SURRAC PPSL Iradiated food screening system (SURRAC, Glasgow, UK). (author)

  12. Delayed Luminescence and Biophotons from Biological Materials

    Science.gov (United States)

    Knoesel, Ernst; Hann, Patrick; Garzon, Maria; Pfeiffer, Erik; Lofland, Samuel

    2008-03-01

    There has recently been increased interest in the field of biophotonics, since it is a non-invasive technique. Many biological systems, such as yeast, bacteria, leaves, seeds, and algae display the unusual phenomenon of a weak, delayed luminescence on the timescale of seconds to minutes after transient illumination. It is also observed that the time decay of the biophotonic emission is not exponential, even after the delay, and that there can be oscillations in intensity with time, which depend on the duration of the illumination. Results from two types of yeast, i.e. bread yeast, and saccharomyces, as well as those from several types of algae are presented. Possible mechanisms for the source of the ultraweak photon emission are discussed.

  13. Sono-luminescence and nuclear fusion

    International Nuclear Information System (INIS)

    Seife, Ch.; Hilgenfeldt, S.; Lohse, D.

    2002-01-01

    This article presents multi-bubble and single-bubble luminescence. Since long scientists have known that ultra-sound waves could trigger the formation of bubbles in water (phenomenon called cavitation) but in 1930, for the first time experiments showed that these bubbles could emit light in particular conditions. In 1989 F. Gaitan succeeded in trapping a single bubble by using stationary ultra-sound waves, this bubble was exploding 20.000 times per second according to the frequency of the wave while emitting a series of flashes of light. Some scientists thought that the gas inside the bubble could reach very high values of temperature and pressure, and proposed the possibility of nuclear fusion to explain the excess of neutrons that has been evidenced in a cavitation experiment with deuterated acetone. The last part of this article describes the controversy triggered by the article describing this experiment, that was published by 'Science' in march 2002. (A.C.)

  14. Metal luminescence in a bright disintegrated prominence

    International Nuclear Information System (INIS)

    Yakovkin, N.A.; Zel'dina, M.Yu.; Rakhubovskij, A.S.; AN Ukrainskoj SSR, Kiev. Glavnaya Astronomicheskaya Observatoriya)

    1975-01-01

    It is found that Na, Mg, Ca, Sc, Ti, Fe, Sr, and Ba contents in a protuberance relative to the hydrogen content is about the same as in photosphere and chromosphere (except for the Na abundance). The metals are in the state of single ionization with the exception of calcium [Ca ++ ] approximately [Ca + ], strontium [Sr ++ ] = 0.5 [Sr + ], and barium [Ba ++ ] = 6Ba + , whose secondary ionization occurs from metastable states by Lsub(α)-emission in the protuberance. The Lsub(α)-emission ionizes neutral iron as well. Primary ionization of remaining metals is performed by the solar near ultraviolet. Luminescence in metal lines is provided by the photosphere emission scattering, and only H and KCa + lines are excited by electron impacts

  15. Detection of irradiated prawns by photostimulated luminescence

    International Nuclear Information System (INIS)

    Chen, Susu; Saito, Kimie; Hagiwara, Shoji; Todoriki, Setsuko; Nakajima, Mitsutoshi

    2011-01-01

    The purpose of this study was to investigate how photostimulated luminescence (PSL) can be applied to verify whether prawns have been irradiated by analyzing their intestinal tracts. Prawns from five different locations which were irradiated at doses of 1 kGy of γ-radiations were analyzed using the Japanese model PSL system. The results showed that the integrated photon counts of all the irradiated samples exceeded the upper threshold value (T 2 =4000 counts/90 s), whereas those of the non-irradiated samples were blew than the lower threshold value (T 1 =1000 counts/90 s). Moreover, using the other parameters which were decrease of intensity after optically stimulation and increase of intensity by optically stimulation, a clear difference was observed between non-irradiated and 1 kGy irradiated samples. Therefore, the Japanese model PSL system can be used as a screening method for detecting irradiated prawns by analyzing their intestinal tracts. (author)

  16. Luminescence properties of lustre decorated majolica

    Science.gov (United States)

    Galli, A.; Martini, M.; Sibilia, E.; Padeletti, G.; Fermo, P.

    Luminescence measurements have been performed on several Italian Renaissance ceramic shards produced in central Italy, as well as on some others from Hispano-Moresque and Fatimid periods. The aim of this study was the characterisation of the raw materials used to manufacture lustre decorated majolica. At first, the thermoluminescence (TL) dating of all ceramic bodies was performed, because the shards lacked sure chronological attribution, having been provided by private collectors, or found during emergency restoration works or archaeological surveys. To characterise the defects and the recombination centers of the different components of the ceramics (ceramic body, glaze, glaze, and lustre), radioluminescence (RL) measurements have been performed on samples representative of each historical period. The dating results are reported, as well as the preliminary RL results.

  17. Luminescent solar concentrators utilizing stimulated emission.

    Science.gov (United States)

    Kaysir, Md Rejvi; Fleming, Simon; MacQueen, Rowan W; Schmidt, Timothy W; Argyros, Alexander

    2016-03-21

    Luminescent solar concentrators (LSCs) are an emerging technology that aims primarily to reduce the cost of solar energy, with great potential for building integrated photovoltaic (PV) structures. However, realizing LSCs with commercially viable efficiency is currently hindered by reabsorption losses. Here, we introduce an approach to reducing reabsorption as well as improving directional emission in LSCs by using stimulated emission. Light from a seed laser (potentially an inexpensive laser diode) passes through the entire area of the LSC panel, modifying the emission spectrum of excited dye molecules such that it is spectrally narrower, at wavelengths that minimize reabsorption to allow net gain in the system, and directed towards a small PV cell. A mathematical model, taking into account thermodynamic considerations, of such a system is presented which identifies key parameters and allows evaluation in terms of net effective output power.

  18. Bacterial lung abscess

    International Nuclear Information System (INIS)

    Groskin, S.A.; Panicek, D.M.; Ewing, D.K.; Rivera, F.; Math, K.; Teixeira, J.; Heitzman, E.R.

    1987-01-01

    A retrospective review of patients with bacterial lung abscess was carried out. Demographic, clinical, and radiographical features of this patient group are compared with similar data from patients with empyema and/or cavitated lung carcinoma; differential diagnostic points are stressed. The entity of radiographically occult lung abscess is discussed. Complications associated with bacterial lung abscess are discussed. Current therapeutic options and treatment philosophy for patients with bacterial lung abscess are noted

  19. Modeling bacterial contamination of fuel ethanol fermentation.

    Science.gov (United States)

    Bischoff, Kenneth M; Liu, Siqing; Leathers, Timothy D; Worthington, Ronald E; Rich, Joseph O

    2009-05-01

    The emergence of antibiotic-resistant bacteria may limit the effectiveness of antibiotics to treat bacterial contamination in fuel ethanol plants, and therefore, new antibacterial intervention methods and tools to test their application are needed. Using shake-flask cultures of Saccharomyces cerevisiae grown on saccharified corn mash and strains of lactic acid bacteria isolated from a dry-grind ethanol facility, a simple model to simulate bacterial contamination and infection was developed. Challenging the model with 10(8) CFU/mL Lactobacillus fermentum decreased ethanol yield by 27% and increased residual glucose from 6.2 to 45.5 g/L. The magnitude of the effect was proportional to the initial bacterial load, with 10(5) CFU/mL L. fermentum still producing an 8% decrease in ethanol and a 3.2-fold increase in residual glucose. Infection was also dependent on the bacterial species used to challenge the fermentation, as neither L. delbrueckii ATCC 4797 nor L. amylovorus 0315-7B produced a significant decrease in ethanol when inoculated at a density of 10(8) CFU/mL. In the shake-flask model, treatment with 2 microg/mL virginiamycin mitigated the infection when challenged with a susceptible strain of L. fermentum (MIC for virginiamycin model may find application in developing new antibacterial agents and management practices for use in controlling contamination in the fuel ethanol industry. Copyright 2008 Wiley Periodicals, Inc.

  20. Peritonitis - spontaneous bacterial

    Science.gov (United States)

    Spontaneous bacterial peritonitis (SBP); Ascites - peritonitis; Cirrhosis - peritonitis ... who are on peritoneal dialysis for kidney failure. Peritonitis may have other causes . These include infection from ...

  1. Intrinsic luminescence of un-doped borate glasses

    International Nuclear Information System (INIS)

    Kindrat, I.I.; Padlyak, B.V.; Drzewiecki, A.

    2017-01-01

    The nature of intrinsic luminescence in the un-doped borate glasses of different compositions has been investigated using spectroscopic methods including photoluminescence, optical absorption, electron paramagnetic resonance (EPR), and thermally stimulated luminescence (TSL). The un-doped borate glasses with Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 basic compositions were obtained from corresponding polycrystalline compounds in the air with usage the standard technology of glasses. Three different broad emission bands in the UV–Visible spectral range have been observed under different wavelength of photoexcitation. The luminescence kinetics of the observed emission bands have been registered and analysed. The nature and possible mechanisms of the intrinsic luminescence in the investigated borate glasses are considered and discussed based on the obtained results and referenced data.

  2. Thermo-optical properties of optically stimulated luminescence in feldspars

    DEFF Research Database (Denmark)

    Poolton, N.R.J.; Bøtter-Jensen, L.; Johnsen, O.

    1995-01-01

    Optically stimulated luminescence processes in feldspars are subject to competing thermal enhancement and quenching processes: this article describes the thermal enhancement effects for orthoclase, albite and plagioclase feldspars. It is demonstrated that certain lattice vibrational modes can be ...

  3. Fabrication and Spectral Properties of Wood-Based Luminescent Nanocomposites

    Directory of Open Access Journals (Sweden)

    Xianjun Li

    2014-01-01

    Full Text Available Pressure impregnation pretreatment is a conventional method to fabricate wood-based nanocomposites. In this paper, the wood-based luminescent nanocomposites were fabricated with the method and its spectral properties were investigated. The results show that it is feasible to fabricate wood-based luminescent nanocomposites using microwave modified wood and nanophosphor powders. The luminescent strength is in positive correlation with the amount of phosphor powders dispersed in urea-formaldehyde resin. Phosphors absorb UV and blue light efficiently in the range of 400–470 nm and show a broad band of bluish-green emission centered at 500 nm, which makes them good candidates for potential blue-green luminescent materials.

  4. Examination of the picture properties of luminescence memory foils

    International Nuclear Information System (INIS)

    Ewert, U.; Heine, S.; Nockemann, C.; Stade, J.; Tillack, G.R.; Wessel, H.; Zscherpel, U.; Mattis, A.

    1995-01-01

    Luminescence memory foils are a new medium for radiography without films. They are known by the name of image plates or digital memory foils. The suitability of such systems for industrial radiography is examined. (orig.) [de

  5. Negative luminescence and devices based on this phenomenon

    International Nuclear Information System (INIS)

    Ivanov-Omskii, V. I.; Matveev, B. A.

    2007-01-01

    Recent publications concerned with infrared emitters whose electrical modulation results in absorption of radiation detected as negative luminescence are reviewed. The main properties of the devices based on this phenomenon are analyzed

  6. Negative luminescence and devices based on this phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov-Omskii, V I; Matveev, B. A. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)], E-mail: bmat@iropt3.ioffe.rssi.ru

    2007-03-15

    Recent publications concerned with infrared emitters whose electrical modulation results in absorption of radiation detected as negative luminescence are reviewed. The main properties of the devices based on this phenomenon are analyzed.

  7. Renewable energy : better luminescent solar panels in prospect

    NARCIS (Netherlands)

    Debije, M.G.

    2015-01-01

    Devices known as luminescent solar concentrators could find use as renewable-energy generators, but have so far been plagued by a major light-reabsorption effect. A new study offers a promising route to tackling this problem

  8. Influence of excitonic effects on luminescence quantum yield in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Sachenko, A.V.; Kostylyov, V.P.; Vlasiuk, V.M. [V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 41 prospect Nauky, 03028 Kyiv (Ukraine); Sokolovskyi, I.O., E-mail: isokolovskyi@mun.ca [V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 41 prospect Nauky, 03028 Kyiv (Ukraine); Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John' s, NL, A1B 3X7 Canada (Canada); Evstigneev, M. [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John' s, NL, A1B 3X7 Canada (Canada)

    2017-03-15

    Nonradiative exciton lifetime in silicon is determined by comparison of the experimental and theoretical curves of bulk minority charge carriers lifetime on doping and excitation levels. This value is used to analyze the influence of excitonic effects on internal luminescence quantum yield at room temperature, taking into account both nonradiative and radiative exciton lifetimes. A range of Shockley-Hall-Reed lifetimes is found, where excitonic effects lead to an increase of internal luminescence quantum yield.

  9. Raman scattering and luminescence of high-Tc superconducting oxides

    International Nuclear Information System (INIS)

    Eremenko, V.V.; Gnezdilov, V.P.; Fomin, V.I.; Fugol', I.Ya.; Samovarov, V.N.

    1989-01-01

    Raman and luminescence spectra of high-T c superconducting oxides are summarized, mainly YBa 2 Cu 3 O 7-σ and partly La 2-x Ba x CuO 4-σ . In raman spectra we succeeded to distinguish electron scattering to define the energy gap Δ in the superconducting state. The luminescence spectra are due to the emission of oxygen and interaction with conduction electrons. 70 refs.; 13 figs

  10. Optical and luminescent properties of the lead and barium molybdates

    Energy Technology Data Exchange (ETDEWEB)

    Spassky, D.A. E-mail: dima@opts.phys.msu.ru; Ivanov, S.N.; Kolobanov, V.N.; Mikhailin, V.V.; Zemskov, V.N.; Zadneprovski, B.I.; Potkin, L.I

    2004-12-01

    Time-resolved luminescence as well as excitation and reflectivity spectra of the oriented lead and barium molybdate single crystals were studied using synchrotron radiation. Features in reflectivity spectra in the fundamental absorption region were analyzed. The contribution of electronic states of lead cation to the formation of the bandgap in PbMoO{sub 4} is supposed. The role of lead states in the intrinsic luminescence of PbMoO{sub 4} is discussed.

  11. Degradation of 4-fluorophenol by Arthrobacter sp strain IF1

    NARCIS (Netherlands)

    Ferreira, Maria Isabel M.; Marchesi, Julian R.; Janssen, Dick B.

    A Gram-positive bacterial strain capable of aerobic biodegradation of 4-fluorophenol (4-FP) as the sole source of carbon and energy was isolated by selective enrichment from soil samples collected near an industrial site. The organism, designated strain IF1, was identified as a member of the genus

  12. Vaginal epithelial cells regulate membrane adhesiveness to co-ordinate bacterial adhesion.

    Science.gov (United States)

    Younes, Jessica A; Klappe, Karin; Kok, Jan Willem; Busscher, Henk J; Reid, Gregor; van der Mei, Henny C

    2016-04-01

    Vaginal epithelium is colonized by different bacterial strains and species. The bacterial composition of vaginal biofilms controls the balance between health and disease. Little is known about the relative contribution of the epithelial and bacterial cell surfaces to bacterial adhesion and whether and how adhesion is regulated over cell membrane regions. Here, we show that bacterial adhesion forces with cell membrane regions not located above the nucleus are stronger than with regions above the nucleus both for vaginal pathogens and different commensal and probiotic lactobacillus strains involved in health. Importantly, adhesion force ratios over membrane regions away from and above the nucleus coincided with the ratios between numbers of adhering bacteria over both regions. Bacterial adhesion forces were dramatically decreased by depleting the epithelial cell membrane of cholesterol or sub-membrane cortical actin. Thus, epithelial cells can regulate membrane regions to which bacterial adhesion is discouraged, possibly to protect the nucleus. © 2015 John Wiley & Sons Ltd.

  13. Role of overexpressed CFA/I fimbriae in bacterial swimming.

    Science.gov (United States)

    Cao, Ling; Suo, Zhiyong; Lim, Timothy; Jun, Sangmu; Deliorman, Muhammedin; Riccardi, Carol; Kellerman, Laura; Avci, Recep; Yang, Xinghong

    2012-06-01

    Enterotoxigenic Escherichia coli CFA/I is a protective antigen and has been overexpressed in bacterial vectors, such as Salmonella Typhimurium H683, to generate vaccines. Effects that overexpressed CFA/I may engender on the bacterial host remain largely unexplored. To investigate, we constructed a high CFA/I expression strain, H683-pC2, and compared it to a low CFA/I expression strain, H683-pC, and to a non-CFA/I expression strain, H683-pY. The results showed that H683-pC2 was less able to migrate into semisolid agar (0.35%) than either H683-pC or H683-pY. Bacteria that migrated showed motility halo sizes of H683-pC2 CFA/I fimbriae on bacterial swimming motility.

  14. Brucella abortus Strain 2308 Wisconsin Genome: Importance of the Definition of Reference Strains

    Science.gov (United States)

    Suárez-Esquivel, Marcela; Ruiz-Villalobos, Nazareth; Castillo-Zeledón, Amanda; Jiménez-Rojas, César; Roop II, R. Martin; Comerci, Diego J.; Barquero-Calvo, Elías; Chacón-Díaz, Carlos; Caswell, Clayton C.; Baker, Kate S.; Chaves-Olarte, Esteban; Thomson, Nicholas R.; Moreno, Edgardo; Letesson, Jean J.; De Bolle, Xavier; Guzmán-Verri, Caterina

    2016-01-01

    Brucellosis is a bacterial infectious disease affecting a wide range of mammals and a neglected zoonosis caused by species of the genetically homogenous genus Brucella. As in most studies on bacterial diseases, research in brucellosis is carried out by using reference strains as canonical models to understand the mechanisms underlying host pathogen interactions. We performed whole genome sequencing analysis of the reference strain B. abortus 2308 routinely used in our laboratory, including manual curated annotation accessible as an editable version through a link at https://en.wikipedia.org/wiki/Brucella#Genomics. Comparison of this genome with two publically available 2308 genomes showed significant differences, particularly indels related to insertional elements, suggesting variability related to the transposition of these elements within the same strain. Considering the outcome of high resolution genomic techniques in the bacteriology field, the conventional concept of strain definition needs to be revised. PMID:27746773

  15. Brucella abortus strain 2308 Wisconsin genome: importance of the definition of reference strains

    Directory of Open Access Journals (Sweden)

    Marcela Suárez-Esquivel

    2016-09-01

    Full Text Available Brucellosis is a bacterial infectious disease affecting a wide range of mammals and a neglected zoonosis caused by species of the genetically homogenous genus Brucella. As in most studies on bacterial diseases, research in brucellosis is carried out by using reference strains as canonical models to understand the mechanisms underlying host pathogen interactions. We performed whole genome sequencing (WGS analysis of the reference strain Brucella abortus 2308 routinely used in our laboratory, including manual curated annotation accessible as an editable version at www.wikipedia.Comparison of this genome with two publically available 2308 genomes showed significant differences, particularly indels related to insertional elements, suggesting variability related to the transposition of these elements within the same strain. Considering the outcome of high resolution genomic techniques in the bacteriology field, the conventional concept of strain definition needs to be revised.

  16. Flight testing of a luminescent surface pressure sensor

    Science.gov (United States)

    Mclachlan, B. G.; Bell, J. H.; Espina, J.; Gallery, J.; Gouterman, M.; Demandante, C. G. N.; Bjarke, L.

    1992-01-01

    NASA ARC has conducted flight tests of a new type of aerodynamic pressure sensor based on a luminescent surface coating. Flights were conducted at the NASA ARC-Dryden Flight Research Facility. The luminescent pressure sensor is based on a surface coating which, when illuminated with ultraviolet light, emits visible light with an intensity dependent on the local air pressure on the surface. This technique makes it possible to obtain pressure data over the entire surface of an aircraft, as opposed to conventional instrumentation, which can only make measurements at pre-selected points. The objective of the flight tests was to evaluate the effectiveness and practicality of a luminescent pressure sensor in the actual flight environment. A luminescent pressure sensor was installed on a fin, the Flight Test Fixture (FTF), that is attached to the underside of an F-104 aircraft. The response of one particular surface coating was evaluated at low supersonic Mach numbers (M = 1.0-1.6) in order to provide an initial estimate of the sensor's capabilities. This memo describes the test approach, the techniques used, and the pressure sensor's behavior under flight conditions. A direct comparison between data provided by the luminescent pressure sensor and that produced by conventional pressure instrumentation shows that the luminescent sensor can provide quantitative data under flight conditions. However, the test results also show that the sensor has a number of limitations which must be addressed if this technique is to prove useful in the flight environment.

  17. Luminescence from cavitation bubbles deformed in uniform pressure gradients

    Science.gov (United States)

    Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Farhat, Mohamed

    2017-09-01

    Presented here are observations that demonstrate how the deformation of millimetric cavitation bubbles by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelength range, 300-900 nm) from the individual collapses of laser-induced bubbles in water. By varying the bubble size, driving pressure, and perceived gravity level aboard parabolic flights, we probed the limit from aspherical to highly spherical bubble collapses. Luminescence was detected for bubbles of maximum radii within the previously uncovered range, R0=1.5 -6 mm, for laser-induced bubbles. The relative luminescence energy was found to rapidly decrease as a function of the bubble asymmetry quantified by the anisotropy parameter ζ , which is the dimensionless equivalent of the Kelvin impulse. As established previously, ζ also dictates the characteristic parameters of bubble-driven microjets. The threshold of ζ beyond which no luminescence is observed in our experiment closely coincides with the threshold where the microjets visibly pierce the bubble and drive a vapor jet during the rebound. The individual fitted blackbody temperatures range between Tlum=7000 and Tlum=11 500 K but do not show any clear trend as a function of ζ . Time-resolved measurements using a high-speed photodetector disclose multiple luminescence events at each bubble collapse. The averaged full width at half-maximum of the pulse is found to scale with R0 and to range between 10 and 20 ns.

  18. [New antibiotics produced by Bacillus subtilis strains].

    Science.gov (United States)

    Malanicheva, I A; Kozlov, D G; Efimenko, T A; Zenkova, V A; Kastrukha, G S; Reznikova, M I; Korolev, A M; Borshchevskaia, L N; Tarasova, O D; Sineokiĭ, S P; Efremenkova, O V

    2014-01-01

    Two Bacillus subtilis strains isolated from the fruiting body of a basidiomycete fungus Pholiota squarrosa exhibited a broad range of antibacterial activity, including those against methicillin-resistant Staphylococcus aureus INA 00761 (MRSA) and Leuconostoc mes6nteroides VKPM B-4177 resistant to glycopep-> tide antibiotics, as well as antifungal activity. The strains were identified as belonging to the "B. subtilis" com- plex based on their morphological and physiological characteristics, as well as by sequencing of the 16S rRNA gene fragments. Both strains (INA 01085 and INA 01086) produced insignificant amounts of polyene antibiotics (hexaen and pentaen, respectively). Strain INA 01086 produced also a cyclic polypeptide antibiotic containing Asp, Gly, Leu, Pro, Tyr, Thr, Trp, and Phe, while the antibiotic of strain INA 01085 contained, apart from these, two unidentified nonproteinaceous amino acids. Both polypeptide antibiotics were new compounds efficient against gram-positive bacteria and able to override the natural bacterial antibiotic resistance.

  19. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    . As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  20. The use of 14C-FIAU to predict bacterial thymidine kinase presence: Implications for radiolabeled FIAU bacterial imaging

    International Nuclear Information System (INIS)

    Peterson, Kristin L.; Reid, William C.; Freeman, Alexandra F.; Holland, Steven M.; Pettigrew, Roderic I.; Gharib, Ahmed M.; Hammoud, Dima A.

    2013-01-01

    Currently available infectious disease imaging techniques cannot differentiate between infection and sterile inflammation or between different types of infections. Recently, radiolabeled FIAU was found to be a substrate for the thymidine kinase (TK) enzyme of multiple pathogenic bacteria, leading to its translational use in the imaging of bacterial infections. Patients with immunodeficiencies, however, are susceptible to a different group of pathogenic bacteria when compared to immunocompetent subjects. In this study, we wanted to predict the usefulness of radiolabeled FIAU in the detection of bacterial infections commonly occurring in patients with immunodeficiencies, in vitro, prior to attempting in vivo imaging with 124 I-FIAU-PET. Methods: We obtained representative strains of bacterial pathogens isolated from actual patients with genetic immunodeficiencies. We evaluated the bacterial susceptibility of different strains to the effect of incubation with FIAU, which would implicate the presence of the thymidine kinase (TK) enzyme. We also incubated the bacteria with 14 C-FIAU and consequently measured its rate of incorporation in the bacterial DNA using a liquid scintillation counter. Results: Unlike the other bacterial strains, the growth of Pseudomonas aeruginosa was not halted by FIAU at any concentration. All the tested clinical isolates demonstrated different levels of 14 C-FIAU uptake, except for P. aeruginosa. Conclusion: Radiolabeled FIAU has been successful in delineating bacterial infections, both in preclinical and pilot translational studies. In patients with immunodeficiencies, Pseudomonas infections are commonly encountered and are usually difficult to differentiate from fungal infections. The use of radiolabeled FIAU for in vivo imaging of those patients, however, would not be useful, considering the apparent lack of TK enzyme in Pseudomonas. One has to keep in mind that not all pathogenic bacteria possess the TK enzyme and as such will not all