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  1. Effects of co-occurring Wolbachia and Spiroplasma endosymbionts on the Drosophila immune response against insect pathogenic and non-pathogenic bacteria.

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    Shokal, Upasana; Yadav, Shruti; Atri, Jaishri; Accetta, Julia; Kenney, Eric; Banks, Katherine; Katakam, Akash; Jaenike, John; Eleftherianos, Ioannis

    2016-02-09

    Symbiotic interactions between microbes and animals are common in nature. Symbiotic organisms are particularly common in insects and, in some cases, they may protect their hosts from pathogenic infections. Wolbachia and Spiroplasma endosymbionts naturally inhabit various insects including Drosophila melanogaster fruit flies. Therefore, this symbiotic association is considered an excellent model to investigate whether endosymbiotic bacteria participate in host immune processes against certain pathogens. Here we have investigated whether the presence of Wolbachia alone or together with Spiroplasma endosymbionts in D. melanogaster adult flies affects the immune response against the virulent insect pathogen Photorhabdus luminescens and against non-pathogenic Escherichia coli bacteria. We found that D. melanogaster flies carrying no endosymbionts, those carrying both Wolbachia and Spiroplasma, and those containing Wolbachia only had similar survival rates after infection with P. luminescens or Escherichia coli bacteria. However, flies carrying both endosymbionts or Wolbachia only contained higher numbers of E. coli cells at early time-points post infection than flies without endosymbiotic bacteria. Interestingly, flies containing Wolbachia only had lower titers of this endosymbiont upon infection with the pathogen P. luminescens than uninfected flies of the same strain. We further found that the presence of Wolbachia and Spiroplasma in D. melanogaster up-regulated certain immune-related genes upon infection with P. luminescens or E. coli bacteria, but it failed to alter the phagocytic ability of the flies toward E. coli inactive bioparticles. Our results suggest that the presence of Wolbachia and Spiroplasma in D. melanogaster can modulate immune signaling against infection by certain insect pathogenic and non-pathogenic bacteria. Results from such studies are important for understanding the molecular basis of the interactions between endosymbiotic bacteria of insects

  2. First human systemic infection caused by Spiroplasma.

    Science.gov (United States)

    Aquilino, Ana; Masiá, Mar; López, Pilar; Galiana, Antonio J; Tovar, Juan; Andrés, María; Gutiérrez, Félix

    2015-02-01

    Spiroplasma species are organisms that normally colonize plants and insects. We describe the first case of human systemic infection caused by Spiroplasma bacteria in a patient with hypogammaglobulinemia undergoing treatment with biological disease-modifying antirheumatic agents. Spiroplasma turonicum was identified through molecular methods in several blood cultures. The infection was successfully treated with doxycycline plus levofloxacin. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  3. Male killing Spiroplasma protects Drosophila melanogaster against two parasitoid wasps

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    Xie, J; Butler, S; Sanchez, G; Mateos, M

    2014-01-01

    Maternally transmitted associations between endosymbiotic bacteria and insects are diverse and widespread in nature. Owing to imperfect vertical transmission, many heritable microbes have evolved compensational mechanisms to enhance their persistence in host lineages, such as manipulating host reproduction and conferring fitness benefits to host. Symbiont-mediated defense against natural enemies of hosts is increasingly recognized as an important mechanism by which endosymbionts enhance host fitness. Members of the genus Spiroplasma associated with distantly related Drosophila hosts are known to engage in either reproductive parasitism (i.e., male killing) or defense against natural enemies (the parasitic wasp Leptopilina heterotoma and a nematode). A male-killing strain of Spiroplasma (strain Melanogaster Sex Ratio Organism (MSRO)) co-occurs with Wolbachia (strain wMel) in certain wild populations of the model organism Drosophila melanogaster. We examined the effects of Spiroplasma MSRO and Wolbachia wMel on Drosophila survival against parasitism by two common wasps, Leptopilina heterotoma and Leptopilina boulardi, that differ in their host ranges and host evasion strategies. The results indicate that Spiroplasma MSRO prevents successful development of both wasps, and confers a small, albeit significant, increase in larva-to-adult survival of flies subjected to wasp attacks. We modeled the conditions under which defense can contribute to Spiroplasma persistence. Wolbachia also confers a weak, but significant, survival advantage to flies attacked by L. heterotoma. The host protective effects exhibited by Spiroplasma and Wolbachia are additive and may provide the conditions for such cotransmitted symbionts to become mutualists. Occurrence of Spiroplasma-mediated protection against distinct parasitoids in divergent Drosophila hosts suggests a general protection mechanism. PMID:24281548

  4. Identification of Spiroplasma insolitum symbionts in Anopheles gambiae [version 1; referees: 2 approved, 1 not approved

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    Sharon T. Chepkemoi

    2017-09-01

    Full Text Available Background: Insect symbionts have the potential to block the transmission of vector-borne diseases by their hosts. The advancement of a symbiont-based transmission blocking strategy for malaria requires the identification and study of Anopheles symbionts. Methods: High throughput 16S amplicon sequencing was used to profile the bacteria associated with Anopheles gambiae sensu lato and identify potential symbionts. The polymerase chain reaction (PCR with specific primers were subsequently used to monitor symbiont prevalence in field populations, as well as symbiont transmission patterns. Results: We report the discovery of the bacterial symbiont, Spiroplasma, in Anopheles gambiae in Kenya. We determine that geographically dispersed Anopheles gambiae populations in Kenya are infected with Spiroplasma at low prevalence levels. Molecular phylogenetics indicates that this Anopheles gambiae associated Spiroplasma is a member of the insolitum clade. We demonstrate that this symbiont is stably maternally transmitted across at least two generations and does not significantly affect the fecundity or egg to adult survival of its host. Conclusions: In diverse insect species, Spiroplasma has been found to render their host resistant to infection by pathogens. The identification of a maternally transmitted strain of Spiroplasma in Anopheles gambiae may therefore open new lines of investigation for the development of symbiont-based strategies for blocking malaria transmission.

  5. Honey bee colonies act as reservoirs for two Spiroplasma facultative symbionts and incur complex, multiyear infection dynamics

    Science.gov (United States)

    Schwarz, Ryan S; Teixeira, Érica Weinstein; Tauber, James P; Birke, Juliane M; Martins, Marta Fonseca; Fonseca, Isabela; Evans, Jay D

    2014-01-01

    Two species of Spiroplasma (Mollicutes) bacteria were isolated from and described as pathogens of the European honey bee, Apis mellifera, ∼30 years ago but recent information on them is lacking despite global concern to understand bee population declines. Here we provide a comprehensive survey for the prevalence of these two Spiroplasma species in current populations of honey bees using improved molecular diagnostic techniques to assay multiyear colony samples from North America (U.S.A.) and South America (Brazil). Significant annual and seasonal fluctuations of Spiroplasma apis and Spiroplasma melliferum prevalence in colonies from the U.S.A. (n = 616) and Brazil (n = 139) occurred during surveys from 2011 through 2013. Overall, 33% of U.S.A. colonies and 54% of Brazil colonies were infected by Spiroplasma spp., where S. melliferum predominated over S. apis in both countries (25% vs. 14% and 44% vs. 38% frequency, respectively). Colonies were co-infected by both species more frequently than expected in both countries and at a much higher rate in Brazil (52%) compared to the U.S.A. (16.5%). U.S.A. samples showed that both species were prevalent not only during spring, as expected from prior research, but also during other seasons. These findings demonstrate that the model of honey bee spiroplasmas as springtime-restricted pathogens needs to be broadened and their role as occasional pathogens considered in current contexts. PMID:24771723

  6. Presencia de Spiroplasma penaei en plancton, bentos y fauna acompañante en fincas camaroneras de Colombia

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    José Altamiranda M.

    2011-05-01

    Full Text Available Objetivo. Determinar la presencia de Spiroplasma penaei en el plancton, bentos y fauna acompañante en 2 fincas comerciales de camarones. Materiales y métodos. Fueron colectadas 200 muestras para identificación de lesiones características de Spiroplasma, a través de la técnica de histología, mientras que para la técnica de PCR se tomaron 326 muestras de plancton, bentos y fauna acompañante. Las muestras colectadas fueron preservadas en tubos estériles con etanol al 95% para análisis de PCR y en solución Davidson para análisis histológicos. Resultados. En los muestreos realizados en las dos fincas camaroneras fue detectada la presencia de Spiroplasma en una muestra de un representante de los dípteros (mosca de agua a través de la técnica de PCR en tiempo real, el cual arrojo una Tm=84, similar a la del control positivo de Spiroplasma utilizado. Esta muestra fue secuenciada y comparada con secuencias de bacterias almacenadas en el banco de datos GenBank usando el algoritmo BLAST, encontrando 100% de homología con un fragmento de los genes ribosomales 16S de la bacteria Spiroplasma penaei. Conclusiones. La mosca de agua es portadora de Spiroplasma penaei, sin embargo no se puede afirmar que este organismo sea el transmisor de la infección, por lo que se recomienda realizar ensayos de tipo experimental con moscas de agua infectadas con Spiroplasma penaei, en camarones libres de patógenos, para evaluar si en realidad es el vector de infección.

  7. Bacterial Infections across the Ants: Frequency and Prevalence of Wolbachia, Spiroplasma, and Asaia

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    Stefanie Kautz

    2013-01-01

    Full Text Available Bacterial endosymbionts are common across insects, but we often lack a deeper knowledge of their prevalence across most organisms. Next-generation sequencing approaches can characterize bacterial diversity associated with a host and at the same time facilitate the fast and simultaneous screening of infectious bacteria. In this study, we used 16S rRNA tag encoded amplicon pyrosequencing to survey bacterial communities of 310 samples representing 221 individuals, 176 colonies and 95 species of ants. We found three distinct endosymbiont groups—Wolbachia (Alphaproteobacteria: Rickettsiales, Spiroplasma (Firmicutes: Entomoplasmatales, and relatives of Asaia (Alphaproteobacteria: Rhodospirillales—at different infection frequencies (at the ant species level: 22.1%, 28.4%, and 14.7%, resp. and relative abundances within bacterial communities (1.0%–99.9%. Spiroplasma was particularly enriched in the ant genus Polyrhachis, while Asaia relatives were most prevalent in arboreal ants of the genus Pseudomyrmex. While Wolbachia and Spiroplasma have been surveyed in ants before, Asaia, an acetic acid bacterium capable of fixing atmospheric nitrogen, has received much less attention. Due to sporadic prevalence across all ant taxa investigated, we hypothesize facultative associations for all three bacterial genera. Infection patterns are discussed in relation to potential adaptation of specific bacteria in certain ant groups.

  8. Horizontal Acquisition and Transcriptional Integration of Novel Genes in Mosquito-Associated Spiroplasma.

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    Lo, Wen-Sui; Kuo, Chih-Horng

    2017-12-01

    Genetic differentiation among symbiotic bacteria is important in shaping biodiversity. The genus Spiroplasma contains species occupying diverse niches and is a model system for symbiont evolution. Previous studies have established that two mosquito-associated species have diverged extensively in their carbohydrate metabolism genes despite having a close phylogenetic relationship. Notably, although the commensal Spiroplasma diminutum lacks identifiable pathogenicity factors, the pathogenic Spiroplasma taiwanense was found to have acquired a virulence factor glpO and its associated genes through horizontal transfer. However, it is unclear if these acquired genes have been integrated into the regulatory network. In this study, we inferred the gene content evolution in these bacteria, as well as examined their transcriptomes in response to glucose availability. The results indicated that both species have many more gene acquisitions from the Mycoides-Entomoplasmataceae clade, which contains several important pathogens of ruminants, than previously thought. Moreover, several acquired genes have higher expression levels than the vertically inherited homologs, indicating possible functional replacement. Finally, the virulence factor and its functionally linked genes in S. taiwanense were up-regulated in response to glucose starvation, suggesting that these acquired genes are under expression regulation and the pathogenicity may be a stress response. In summary, although differential gene losses are a major process for symbiont divergence, gene gains are critical in counteracting genome degradation and driving diversification among facultative symbionts. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  9. Engineering bacteria for enhanced polyhydroxyalkanoates (PHA biosynthesis

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    Guo-Qiang Chen

    2017-09-01

    Full Text Available Polyhydroxyalkanoates (PHA have been produced by some bacteria as bioplastics for many years. Yet their commercialization is still on the way. A few issues are related to the difficulty of PHA commercialization: namely, high cost and instabilities on molecular weights (Mw and structures, thus instability on thermo-mechanical properties. The high cost is the result of complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and slow growth of microorganisms as well as difficulty of downstream separation. Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles, developments of engineering approaches for the extremophiles, increase on carbon substrates to PHA conversion and controlling Mw of PHA. The concept proof studies could still be conducted on E. coli or Pseudomonas spp. that are easily used for molecular manipulations. In this review, we will use E. coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.

  10. Hepatitis From Spiroplasma sp. in an Immunocompromised Patient.

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    Mueller, N J; Tini, G M; Weber, A; Gaspert, A; Husmann, L; Bloemberg, G; Boehler, A; Benden, C

    2015-09-01

    A 70-year-old lung transplant recipient patient was admitted with fever, nausea, abdominal pain, peripheral edema and pronounced weakness. An initial work-up for presumed infection revealed cholestatic hepatitis, leukocytosis and thrombocytopenia, but failed to detect a pathogen. An increased glucose uptake exclusively in the liver was demonstrated by positron emission tomography. Liver biopsy showed basophilic inclusions in the cytoplasm of hepatocytes. Broad- range 16S rRNA gene PCR followed by sequence analysis yielded Spiroplasma sp. in two independent blood samples and the liver biopsy, confirming Spiroplasma sp. as the causative agent. Antibiotic treatment with doxycycline and azithromycin led to complete recovery. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

  11. Chemically enhanced sunlight for killing bacteria

    International Nuclear Information System (INIS)

    Block, S.S.; Goswami, D.Y.

    1995-01-01

    Solar ultraviolet (UV) photocatalyzed oxidation of chemicals with titanium dioxide (TiO 2 ) has received considerable attention. Much less recognized, however, is the ability of the same system to destroy bacteria. This study examined this phenomenon and the conditions that affect it. Bacteria in aqueous solution were given solar exposure with titanium dioxide and their survival with time was determined. Lamps with a predominantly solar ultraviolet spectrum were also used in the experiments. Without exposure to UV light, TiO 2 had no deleterious effect on the bacteria. However, several common bacteria on solar exposure in the presence of TiO 2 were killed in just a few minutes, whereas without TiO 2 it took over an hour to destroy them. A concentration of 0.01% TiO 2 was most effective in killing bacteria and 10-fold concentrations lower or higher were successively less effective. Inorganic and organic compounds in solution, even in small amounts, interfered with the efficiency of killing. Alkaline solution also reduced the bactericidal activity. Circulation and agitation provided by stirring to keep the TiO 2 particles suspended reduced the time necessary to kill the bacteria. Time-intensity curves for killing bacteria were the same general shape with or without TiO 2 , indicating that TiO 2 served merely as a catalyst to increase the rate of the reaction but that the mechanism of action was not changed. The shape of the curves show that the organisms are sensitized with a minimum intensity of radiation and that an increase doesn't greatly increase the rate of kill. Below this critical intensity, however, the time required for killing markedly increases as the intensity is decreased

  12. Ultraviolet irradiation mutagenesis and recombination in spiroplasma citri

    Energy Technology Data Exchange (ETDEWEB)

    Labarere, J.; Barroso, G. (Bordeaux-2 Univ., 33 (France))

    1984-09-01

    A method for obtaining and screening uv-induced mutants from Spiroplasma citri is described. Lethality response curves showed that S. citri is more sensitive to uv irradiation than are other microorganisms. The presence of a shoulder in the lethality response curve showed the existence of systems able to repair uv-induced DNA damages. Toxic-resistant mutants have been obtained. A uv fluence equal to 10 J/m/sup 2/ multiplied by 2.5x10/sup 3/ gave the spontaneous mutation frequency. Arsenic acid- and xylitol-resistant mutants were used to investigate transfer of genetic information in S. citri. After 90 min of incubation, the recombination frequency was 5x10/sup -5/.

  13. Silver enhances antibiotic activity against gram-negative bacteria.

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    Morones-Ramirez, J Ruben; Winkler, Jonathan A; Spina, Catherine S; Collins, James J

    2013-06-19

    A declining pipeline of clinically useful antibiotics has made it imperative to develop more effective antimicrobial therapies, particularly against difficult-to-treat Gram-negative pathogens. Silver has been used as an antimicrobial since antiquity, yet its mechanism of action remains unclear. We show that silver disrupts multiple bacterial cellular processes, including disulfide bond formation, metabolism, and iron homeostasis. These changes lead to increased production of reactive oxygen species and increased membrane permeability of Gram-negative bacteria that can potentiate the activity of a broad range of antibiotics against Gram-negative bacteria in different metabolic states, as well as restore antibiotic susceptibility to a resistant bacterial strain. We show both in vitro and in a mouse model of urinary tract infection that the ability of silver to induce oxidative stress can be harnessed to potentiate antibiotic activity. Additionally, we demonstrate in vitro and in two different mouse models of peritonitis that silver sensitizes Gram-negative bacteria to the Gram-positive-specific antibiotic vancomycin, thereby expanding the antibacterial spectrum of this drug. Finally, we used silver and antibiotic combinations in vitro to eradicate bacterial persister cells, and show both in vitro and in a mouse biofilm infection model that silver can enhance antibacterial action against bacteria that produce biofilms. This work shows that silver can be used to enhance the action of existing antibiotics against Gram-negative bacteria, thus strengthening the antibiotic arsenal for fighting bacterial infections.

  14. The monomeric, tetrameric, and fibrillar organization of Fib: the dynamic building block of the bacterial linear motor of Spiroplasma melliferum BC3.

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    Cohen-Krausz, Sara; Cabahug, Pamela C; Trachtenberg, Shlomo

    2011-07-08

    Spiroplasmas belong to the class Mollicutes, representing the minimal, free-living, and self-replicating forms of life. Spiroplasmas are helical wall-less bacteria and the only ones known to swim by means of a linear motor (rather than the near-universal rotary bacterial motor). The linear motor follows the shortest path along the cell's helical membranal tube. The motor is composed of a flat monolayered ribbon of seven parallel fibrils and is believed to function in controlling cell helicity and motility through dynamic, coordinated, differential length changes in the fibrils. The latter cause local perturbations of helical symmetry, which are essential for net directional displacement in environments with a low Reynolds number. The underlying fibrils' core building block is a circular tetramer of the 59-kDa protein Fib. The fibrils' differential length changes are believed to be driven by molecular switching of Fib, leading consequently to axial ratio and length changes in tetrameric rings. Using cryo electron microscopy, diffractometry, single-particle analysis of isolated ribbons, and sequence analyses of Fib, we determined the overall molecular organization of the Fib monomer, tetramer, fibril, and linear motor of Spiroplasma melliferum BC3 that underlies cell geometry and motility. Fib appears to be a bidomained molecule, of which the N-terminal half is apparently a globular phosphorylase. By a combination of reversible rotation and diagonal shift of Fib monomers, the tetramer adopts either a cross-like nonhanded conformation or a ring-like handed conformation. The sense of Fib rotation may determine the handedness of the linear motor and, eventually, of the cell. A further change in the axial ratio of the ring-like tetramers controls fibril lengths and the consequent helical geometry. Analysis of tetramer quadrants from adjacent fibrils clearly demonstrates local differential fibril lengths. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Prevalence of pathogenic bacteria in Ixodes ricinus ticks in Central Bohemia.

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    Klubal, Radek; Kopecky, Jan; Nesvorna, Marta; Sparagano, Olivier A E; Thomayerova, Jana; Hubert, Jan

    2016-01-01

    Bacteria associated with the tick Ixodes ricinus were assessed in specimens unattached or attached to the skin of cats, dogs and humans, collected in the Czech Republic. The bacteria were detected by PCR in 97 of 142 pooled samples including 204 ticks, i.e. 1-7 ticks per sample, collected at the same time from one host. A fragment of the bacterial 16S rRNA gene was amplified, cloned and sequenced from 32 randomly selected samples. The most frequent sequences were those related to Candidatus Midichloria midichlori (71% of cloned sequences), followed by Diplorickettsia (13%), Spiroplasma (3%), Rickettsia (3%), Pasteurella (3%), Morganella (3%), Pseudomonas (2%), Bacillus (1%), Methylobacterium (1%) and Phyllobacterium (1%). The phylogenetic analysis of Spiroplasma 16S rRNA gene sequences showed two groups related to Spiroplasma eriocheiris and Spiroplasma melliferum, respectively. Using group-specific primers, the following potentially pathogenic bacteria were detected: Borellia (in 20% of the 142 samples), Rickettsia (12%), Spiroplasma (5%), Diplorickettsia (5%) and Anaplasma (2%). In total, 68% of I. ricinus samples (97/142) contained detectable bacteria and 13% contained two or more putative pathogenic groups. The prevalence of tick-borne bacteria was similar to the observations in other European countries.

  16. Detection of Spiroplasma melliferum in honey bee colonies in the US.

    Science.gov (United States)

    Zheng, Huo-Qing; Chen, Yan Ping

    2014-06-01

    Spiroplasma infections in honey bees have been reported in Europe and Asia quite recently, due to intensive studies on the epidemiology of honey bee diseases. The situation in the US is less well analyzed. Here, we examined the honey bee colonies in Beltsville, MD, where Spiroplasmamelliferum was originally reported and found S. melliferum infection in honey bees. Our data showed high variation of S. melliferum infection in honey bees with a peak prevalence in May during the course of one-year study period. The colony prevalence increased from 5% in February to 68% in May and then decreased to 25% in June and 22% in July. Despite that pathogenicity of spiroplasmas in honey bee colonies remains to be determined, our results indicated that spiroplasma infections need to be included for the consideration of the impacts on honey bee health. Published by Elsevier Inc.

  17. Molecular Detection of Spiroplasma Citri Associated with Stubborn Disease in Citrus Orchards in Syria

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    Spiroplasma citri, a phloem-limited pathogen, causes citrus stubborn disease (CSD) and can be transmitted from plant to plant by several species of phloem-feeding leafhoppers. CSD is an important disorder in certain warm and arid citrus-growing areas, and its agent has been recorded from several Med...

  18. Detection of Spiroplasma and Wolbachia in the bacterial gonad community of Chorthippus parallelus.

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    Martínez-Rodríguez, P; Hernández-Pérez, M; Bella, J L

    2013-07-01

    We have recently detected the endosymbiont Wolbachia in multiple individuals and populations of the grasshopper Chorthippus parallelus (Orthoptera: acrididae). This bacterium induces reproductive anomalies, including cytoplasmic incompatibility. Such incompatibilities may help explain the maintenance of two distinct subspecies of this grasshopper, C. parallelus parallelus and C. parallelus erythropus, which are involved in a Pyrenean hybrid zone that has been extensively studied for the past 20 years, becoming a model system for the study of genetic divergence and speciation. To evaluate whether Wolbachia is the sole bacterial infection that might induce reproductive anomalies, the gonadal bacterial community of individuals from 13 distinct populations of C. parallelus was determined by denaturing gradient gel electrophoresis analysis of bacterial 16S rRNA gene fragments and sequencing. The study revealed low bacterial diversity in the gonads: a persistent bacterial trio consistent with Spiroplasma sp. and the two previously described supergroups of Wolbachia (B and F) dominated the gonad microbiota. A further evaluation of the composition of the gonad bacterial communities was carried out by whole cell hybridization. Our results confirm previous studies of the cytological distribution of Wolbachia in C. parallelus gonads and show a homogeneous infection by Spiroplasma. Spiroplasma and Wolbachia cooccurred in some individuals, but there was no significant association of Spiroplasma with a grasshopper's sex or with Wolbachia infection, although subtle trends might be detected with a larger sample size. This information, together with previous experimental crosses of this grasshopper, suggests that Spiroplasma is unlikely to contribute to sex-specific reproductive anomalies; instead, they implicate Wolbachia as the agent of the observed anomalies in C. parallelus.

  19. Short communication: Lactose enhances bile tolerance of yogurt culture bacteria.

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    Mena, Behannis; Aryana, Kayanush

    2018-03-01

    Lactose is an energy source for culture bacteria. Bile tolerance is an important probiotic property. Our aim was to elucidate the effect of lactose on bile tolerance of yogurt starter culture Lactobacillus bulgaricus LB-12 and Streptococcus thermophilus ST-M5. Bile tolerance of pure cultures was determined using 0.3% oxgall in MRS THIO broth (Difco, Becton Dickinson, Sparks, MD) for L. bulgaricus and 0.3% oxgall in M17 broth (Oxoid, Basingstoke, UK) for Strep. thermophilus. Lactose was added to both broths at 0 (control), 1, 3, and 5% (wt/vol) broth. Dilutions were plated hourly for 12 h. Experiments were replicated 3 times. At 2, 4, and 12 h of incubation, lactose incorporated at all amounts, 1, 3, and 5% (wt/vol), showed higher counts of Strep. thermophilus ST-M5 compared with the control. Lactose use at 5% (wt/vol) significantly enhanced bile tolerance of both L. bulgaricus and Strep. thermophilus compared with control. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  20. Energy sources of yoghurt bacteria and enhancement of their ...

    African Journals Online (AJOL)

    The energy sources of yoghurt bacteria (Streptococcus thermophilus and Lactobacillus bulgaricus) were examined with a focus on probable impact of sucrose on their galactose uptake. Yoghurt bacteria were isolated from samples of yoghurt which were purchased from different outlets and kept under refrigeration ...

  1. Complete Genome Sequence of Spiroplasma floricola 23-6T (ATCC 29989), a Bacterium Isolated from a Tulip Tree (Liriodendron tulipifera L.).

    Science.gov (United States)

    Tsai, Yi-Ming; Wu, Pei-Shan; Lo, Wen-Sui; Kuo, Chih-Horng

    2018-04-19

    Spiroplasma floricola 23-6 T (ATCC 29989) was isolated from the flower surface of a tulip tree ( Liriodendron tulipifera L.). Here, we report the complete genome sequence of this bacterium to facilitate the investigation of its biology and the comparative genomics among Spiroplasma species. Copyright © 2018 Tsai et al.

  2. Challenging the Wigglesworthia, Sodalis, Wolbachia symbiosis dogma in tsetse flies: Spiroplasma is present in both laboratory and natural populations.

    Science.gov (United States)

    Doudoumis, V; Blow, F; Saridaki, A; Augustinos, A; Dyer, N A; Goodhead, I; Solano, P; Rayaisse, J-B; Takac, P; Mekonnen, S; Parker, A G; Abd-Alla, A M M; Darby, A; Bourtzis, K; Tsiamis, G

    2017-07-05

    Profiling of wild and laboratory tsetse populations using 16S rRNA gene amplicon sequencing allowed us to examine whether the "Wigglesworthia-Sodalis-Wolbachia dogma" operates across species and populations. The most abundant taxa, in wild and laboratory populations, were Wigglesworthia (the primary endosymbiont), Sodalis and Wolbachia as previously characterized. The species richness of the microbiota was greater in wild than laboratory populations. Spiroplasma was identified as a new symbiont exclusively in Glossina fuscipes fuscipes and G. tachinoides, members of the palpalis sub-group, and the infection prevalence in several laboratory and natural populations was surveyed. Multi locus sequencing typing (MLST) analysis identified two strains of tsetse-associated Spiroplasma, present in G. f. fuscipes and G. tachinoides. Spiroplasma density in G. f. fuscipes larva guts was significantly higher than in guts from teneral and 15-day old male and female adults. In gonads of teneral and 15-day old insects, Spiroplasma density was higher in testes than ovaries, and was significantly higher density in live versus prematurely deceased females indicating a potentially mutualistic association. Higher Spiroplasma density in testes than in ovaries was also detected by fluorescent in situ hybridization in G. f. fuscipes.

  3. Energy sources of yoghurt bacteria and enhancement of their ...

    African Journals Online (AJOL)

    Administrator

    2011-05-23

    May 23, 2011 ... starter culture consists of two symbiotically growing bacteria, S. thermophilus .... inoculated aseptically with pure colonies of the bacterial isolates. All ..... load and enzyme production of indigenously isolated yeast. Pak. J. Bot.

  4. GENOMIC ANALYSIS OF PLANT-ASSOCIATED BACTERIA AND THEIR POTENTIAL IN ENHANCING PHYTOREMEDIATION EFFICIENCY

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    Artur Piński

    2017-07-01

    Full Text Available Phytoremediation is an emerging technology that uses plants in order to cleanup pollutants including xenobiotics and heavy metals from soil, water and air. Inoculation of plants with plant growth promoting endophytic and rhizospheric bacteria can enhance efficiency of phytoremediation. Genomic analysis of four plant-associated strains belonging to the Stenotrophomonas maltophilia species revealed the presence of genes encoding proteins involved in plant growth promotion, biocontrol of phytopathogens, biodegradation of xenobiotics, heavy metals resistance and plant-bacteria-environment interaction. The results of this analysis suggest great potential of bacteria belonging to Stenotrophomonas maltophilia species in enhancing phytoremediation efficiency.

  5. Enhanced sulfate reduction with acidogenic sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Wang Aijie; Ren Nanqi; Wang Xu; Lee Duujong

    2008-01-01

    Sulfate reduction in a continuous flow, acidogenic reactor using molasses wastewater as the carbon source was studied at varying chemical oxygen demand/sulfate (COD/SO 4 2- ) ratios. At a critical COD/SO 4 2- ratio of 2.7, neither COD nor sulfate were in excess for extra production of ethanol or acetate in the reactor. An acetic-type microbial metabolism was established with sulfate-reducing bacteria (SRB) significantly consuming hydrogen and volatile fatty acids produced by acidogenic bacteria and hydrogen producing acetogens in degrading COD, thereby yielding sulfate removal rate >94.6%. A low critical COD/SO 4 2- ratio of 1.6 was also observed with the enriched ASRB population in reactor which overcomes the barrier to the treatment capability of sulfate-laden wastewater treatment with limited COD supply

  6. Enhancement of properties of recycled coarse aggregate concrete using bacteria

    Science.gov (United States)

    Sahoo; Arakha; Sarkar; P; Jha

    2016-01-01

    Due to rapid construction, necessity for raw materials of concrete, especially coarse aggregate, tends to increase the danger of early exhaustion of the natural resources. An alternative source of raw materials would perhaps delay the advent of this early exhaustion. Recycled coarse aggregate (RCA) plays a great role as an alternative raw material that can replace the natural coarse aggregate (NCA) for concrete. Previous studies show that the properties of RCA concrete are inferior in quality compared to NCA concrete. This article attempts to study the improvement of properties of RCA concrete with the addition of bacteria named as Bacillus subtilis. The experimental investigation was carried out to evaluate the improvement of the compressive strength, capillary water absorption, and drying shrinkage of RCA concrete incorporating bacteria. The compressive strength of RCA concrete is found to be increased by about 20% when the cell concentration of B. subtilis is 106 cells/ml. The capillary water absorption as well as drying shrinkage of RCA are reduced when bacteria is incorporated. The improvement of RCA concrete is confirmed to be due to the calcium carbonate precipitation as observed from the microstructure studies carried out on it such as EDX, SEM, and XRD.

  7. Lactic acid bacteria: promising supplements for enhancing the biological activities of kombucha.

    Science.gov (United States)

    Nguyen, Nguyen Khoi; Dong, Ngan Thi Ngoc; Nguyen, Huong Thuy; Le, Phu Hong

    2015-01-01

    Kombucha is sweetened black tea that is fermented by a symbiosis of bacteria and yeast embedded within a cellulose membrane. It is considered a health drink in many countries because it is a rich source of vitamins and may have other health benefits. It has previously been reported that adding lactic acid bacteria (Lactobacillus) strains to kombucha can enhance its biological functions, but in that study only lactic acid bacteria isolated from kefir grains were tested. There are many other natural sources of lactic acid bacteria. In this study, we examined the effects of lactic acid bacteria from various fermented Vietnamese food sources (pickled cabbage, kefir and kombucha) on kombucha's three main biological functions: glucuronic acid production, antibacterial activity and antioxidant ability. Glucuronic acid production was determined by high-performance liquid chromatography-mass spectrometry, antibacterial activity was assessed by the agar-well diffusion method and antioxidant ability was evaluated by determining the 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity. Four strains of food-borne pathogenic bacteria were used in our antibacterial experiments: Listeria monocytogenes ATCC 19111, Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028 and Bacillus cereus ATCC 11778. Our findings showed that lactic acid bacteria strains isolated from kefir are superior to those from other sources for improving glucuronic acid production and enhancing the antibacterial and antioxidant activities of kombucha. This study illustrates the potential of Lactobacillus casei and Lactobacillus plantarum isolated from kefir as biosupplements for enhancing the bioactivities of kombucha.

  8. Copper-resistant bacteria enhance plant growth and copper phytoextraction.

    Science.gov (United States)

    Yang, Renxiu; Luo, Chunling; Chen, Yahua; Wang, Guiping; Xu, Yue; Shen, Zhenguo

    2013-01-01

    In this study, we investigated the role of rhizospheric bacteria in solubilizing soil copper (Cu) and promoting plant growth. The Cu-resistant bacterium DGS6 was isolated from a natural Cu-contaminated soil and was identified as Pseudomonas sp. DGS6. This isolate solubilized Cu in Cu-contaminated soil and stimulated root elongation of maize and sunflower. Maize was more sensitive to inoculation with DGS6 than was sunflower and exhibited greater root elongation. In pot experiment, inoculation with DGS6 increased the shoot dry weight of maize by 49% and sunflower by 34%, and increased the root dry weight of maize by 85% and sunflower by 45%. Although the concentrations of Cu in inoculated and non-inoculated seedlings did not differ significantly, the total accumulation of Cu in the plants increased after inoculation. DGS6 showed a high ability to solubilize P and produce iron-chelating siderophores, as well as significantly improved the accumulation of P and Fe in both maize and sunflower shoots. In addition, DGS6 produced indole-3-acetic acid (IAA) and ACC deaminase, which suggests that it may modulate ethylene levels in plants. The bacterial strain DGS6 could be a good candidate for re-vegetation of Cu-contaminated sites. Supplemental materials are available for this article. Go to the publisher's online edition of International Journal of Phytoremediation to view the supplemental file.

  9. Molecular evolution of the actin-like MreB protein gene family in wall-less bacteria.

    Science.gov (United States)

    Ku, Chuan; Lo, Wen-Sui; Kuo, Chih-Horng

    2014-04-18

    The mreB gene family encodes actin-like proteins that determine cell shape by directing cell wall synthesis and often exists in one to three copies in the genomes of non-spherical bacteria. Intriguingly, while most wall-less bacteria do not have this gene, five to seven mreB homologs are found in Spiroplasma and Haloplasma, which are both characterized by cell contractility. To investigate the molecular evolution of this gene family in wall-less bacteria, we sampled the available genome sequences from these two genera and other related lineages for comparative analysis. The gene phylogenies indicated that the mreB homologs in Haloplasma are more closely related to those in Firmicutes, whereas those in Spiroplasma form a separate clade. This finding suggests that the gene family expansions in these two lineages are the results of independent ancient duplications. Moreover, the Spiroplasma mreB homologs can be classified into five clades, of which the genomic positions are largely conserved. The inference of gene gains and losses suggests that there has been an overall trend to retain only one homolog from each of the five mreB clades in the evolutionary history of Spiroplasma. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Biofilms Formed by Gram-Negative Bacteria Undergo Increased Lipid A Palmitoylation, Enhancing In Vivo Survival

    Science.gov (United States)

    Chalabaev, Sabina; Chauhan, Ashwini; Novikov, Alexey; Iyer, Pavithra; Szczesny, Magdalena; Beloin, Christophe; Caroff, Martine

    2014-01-01

    ABSTRACT Bacterial biofilm communities are associated with profound physiological changes that lead to novel properties compared to the properties of individual (planktonic) bacteria. The study of biofilm-associated phenotypes is an essential step toward control of deleterious effects of pathogenic biofilms. Here we investigated lipopolysaccharide (LPS) structural modifications in Escherichia coli biofilm bacteria, and we showed that all tested commensal and pathogenic E. coli biofilm bacteria display LPS modifications corresponding to an increased level of incorporation of palmitate acyl chain (palmitoylation) into lipid A compared to planktonic bacteria. Genetic analysis showed that lipid A palmitoylation in biofilms is mediated by the PagP enzyme, which is regulated by the histone-like protein repressor H-NS and the SlyA regulator. While lipid A palmitoylation does not influence bacterial adhesion, it weakens inflammatory response and enhances resistance to some antimicrobial peptides. Moreover, we showed that lipid A palmitoylation increases in vivo survival of biofilm bacteria in a clinically relevant model of catheter infection, potentially contributing to biofilm tolerance to host immune defenses. The widespread occurrence of increased lipid A palmitoylation in biofilms formed by all tested bacteria suggests that it constitutes a new biofilm-associated phenotype in Gram-negative bacteria. PMID:25139899

  11. Radiosensitization: enhancing the radiation inactivation of foodborne bacteria

    Science.gov (United States)

    Borsa, J.; Lacroix, M.; Ouattara, B.; Chiasson, F.

    2004-09-01

    Irradiation of meat products to kill pathogens can be limited by radiation-induced detriment of sensory quality. Since such detriment is directly related to dose, one approach to reduce it is by devising means to lower the dose of radiation required for processing. Increasing the radiation sensitivity of the target microorganisms would lower the dose required for a given level of microbial kill. In this work, the radiation sensitivities of inoculated Escherichia coli and Salmonella typhi in ground beef were examined under a variety of conditions. Results showed that specific manipulations of treatment conditions significantly increased the radiation sensitivity of the test organisms, ranging from a few percent to several-fold reduction in D10. In particular, radiation sensitization could be effected by certain additives, including carvacrol, thymol and trans-cinnamaldehyde, and also by certain compositions of modified atmosphere in the package headspace. A combination of additives and modified atmosphere effected a greater radiosensitization effect than could be achieved by either factor applied alone. Radiosensitization could be demonstrated with irradiation of either fresh or frozen ground meat. The radiosensitization phenomenon may be of practical utility in enhancing the technical effectiveness and feasibility of irradiation of a variety of meat and other food products.

  12. Radiosensitization: enhancing the radiation inactivation of foodborne bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Borsa, J. E-mail: jborsa@mds.nordion.com; Lacroix, M.; Ouattara, B.; Chiasson, F

    2004-10-01

    Irradiation of meat products to kill pathogens can be limited by radiation-induced detriment of sensory quality. Since such detriment is directly related to dose, one approach to reduce it is by devising means to lower the dose of radiation required for processing. Increasing the radiation sensitivity of the target microorganisms would lower the dose required for a given level of microbial kill. In this work, the radiation sensitivities of inoculated Escherichia coli and Salmonella typhi in ground beef were examined under a variety of conditions. Results showed that specific manipulations of treatment conditions significantly increased the radiation sensitivity of the test organisms, ranging from a few percent to several-fold reduction in D{sub 10}. In particular, radiation sensitization could be effected by certain additives, including carvacrol, thymol and trans-cinnamaldehyde, and also by certain compositions of modified atmosphere in the package headspace. A combination of additives and modified atmosphere effected a greater radiosensitization effect than could be achieved by either factor applied alone. Radiosensitization could be demonstrated with irradiation of either fresh or frozen ground meat. The radiosensitization phenomenon may be of practical utility in enhancing the technical effectiveness and feasibility of irradiation of a variety of meat and other food products.

  13. Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

    Science.gov (United States)

    Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

    2003-01-01

    The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

  14. An aptamer cocktail-functionalized photocatalyst with enhanced antibacterial efficiency towards target bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Song, Min Young [Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of); Jurng, Jongsoo [Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of); Department of Energy and Environmental Engineering, University of Science and Technology (UST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of); Park, Young-Kwon [School of Environmental Engineering, University of Seoul, Seoulsiripdae-ro 163, Dongdaemun-gu, Seoul 02504 (Korea, Republic of); Kim, Byoung Chan, E-mail: bchankim@kist.re.kr [Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of); Department of Energy and Environmental Engineering, University of Science and Technology (UST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of)

    2016-11-15

    Highlights: • Aptamer-conjugated TiO{sub 2} was developed for target-specific bacterial inactivation. • TiO{sub 2}-aptamer cocktail can enhance inactivation of target bacteria faster than TiO{sub 2}. • TiO{sub 2}-aptamer cocktail can enhance inactivation of target bacteria in mixed culture. • Efficient ROS transfer to the bacteria is caused by close contact of TiO{sub 2}-aptamer. - Abstract: We developed TiO{sub 2} particles conjugated with an Escherichia coli surface-specific ssDNA aptamer cocktail (composed of three different aptamers isolated from E. coli) for targeted and enhanced disinfection of E. coli. We examined the target-specific and enhanced inactivation of this composite (TiO{sub 2}-Apc), which were compared to those of TiO{sub 2} conjugated with a single aptamer (one of the three different aptamers, TiO{sub 2}-Aps) and non-modified TiO{sub 2}. We found that TiO{sub 2}-Apc enhanced the inactivation of targeted E. coli under UV irradiation compared to both the non-modified TiO{sub 2} and TiO{sub 2}-Aps. A higher number of TiO{sub 2}-Apc than TiO{sub 2}-Aps particles was observed on the surface of E. coli. The amount of TiO{sub 2}-Apc required to inactivate ∼99.9% of E. coli (10{sup 6} CFU/ml) was 10 times lower than that of non-modified TiO{sub 2}. The close proximity of functionalized particles with E. coli resulting from the interaction between the target surface and the aptamer induced the efficient and fast transfer of reactive oxygen species to the cells. In a mixed culture of different bacteria (E. coli and Staphylococcus epidermidis), TiO{sub 2}-Apc enhanced the inactivation of only E. coli. Taken together, these results support the use of aptamer cocktail-conjugated TiO{sub 2} for improvement of the target-specific inactivation of bacteria.

  15. Microbial enhanced oil recovery—a modeling study of the potential of spore-forming bacteria

    DEFF Research Database (Denmark)

    Nielsen, Sidsel Marie; Nesterov, Igor; Shapiro, Alexander

    2016-01-01

    resulted in the following conclusions. In order to obtain sufficient local concentrations of surfactant, substantial amounts of substrate should be supplied; however, massive growth of bacteria increases the risk for clogging at the well inlet areas, causing injectivity loss. In such areas, starvation may......Microbial enhanced oil recovery (MEOR) utilizes microbes for enhancing the recovery by several mechanisms, among which the most studied are the following: (1) reduction of oil-water interfacial tension (IFT) by the produced biosurfactant and (2) selective plugging by microbes and metabolic products...

  16. use of gamma irradiation for enhancing antibacterial activity of chitosan against pathogenic bacteria

    International Nuclear Information System (INIS)

    Taha, S.M.A.; Swailam, H.M.H.

    2009-01-01

    the effect of chitosan on growth of food poisoning bacteria including gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) and gram-positive bacteria (Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus) was investigated at ph 6.0 and 7.0 also, the effect of irradiation on the antibacterial activity of chitosan was studied . it was found that chitosan was more effective on the growth of gram-negative bacteria at ph 6 than ph 7 . addition of chitosan affected the growth of the tested pathogens in varying degrees compared to the control. as the concentration of chitosan increased, its effectiveness against these pathogens also increased. the growth for gram-positive and gram-negative bacterial isolates was completely inhibited at 0.6% chitosan after 72 hours of incubation. inactivation of these pathogens needs only 24 hour with 1.0% of chitosan. irradiation of chitosan at 50 kGy slightly increased the antimicrobial activity whereas at 100 kGy increased the antimicrobial activity and at 150 kGy the growth of these pathogens was completely inhibited . irradiation of chitosan at 50 kGy increased the flow index, whereas consistency index markedly decreased by increasing dose. the minimum inhibitory concentration (MIC) of unirradiated chitosan ranged from 0.35% to 0.50%, whereas the MIC of irradiated chitosan ranged from 0.1% to 0.45% depending on the bacteria and the irradiation dose used. these results demonstrate that irradiated chitosan was more effective to decontaminate pathogenic bacteria and can be easily used in different foods for enhancing health quality and ensuring safety

  17. Predicting Bacteria Removal by Enhanced Stormwater Control Measures (SCMs) at the Watershed Scale

    Science.gov (United States)

    Wolfand, J.; Bell, C. D.; Boehm, A. B.; Hogue, T. S.; Luthy, R. G.

    2017-12-01

    Urban stormwater is a major cause of water quality impairment, resulting in surface waters that fail to meet water quality standards and support their designated uses. Fecal indicator bacteria are present in high concentrations in stormwater and are strictly regulated in receiving waters; yet, their fate and transport in urban stormwater is poorly understood. Stormwater control measures (SCMs) are often used to treat, infiltrate, and release urban runoff, but field measurements show that the removal of bacteria by these structural solutions is limited (median log removal = 0.24, n = 370). Researchers have therefore looked to improve bacterial removal by enhancing SCMs through alterations in flow regimes or adding geomedia such as biochar. The present research seeks to develop a model to predict removal of fecal indicator bacteria by enhanced SCMs at the watershed scale in a semi-arid climate. Using the highly developed Ballona Creek watershed (290 km2) located in Los Angeles County as a case study, a hydrologic model is coupled with a stochastic water quality model to predict E. coli concentration near the outfall of the Ballona Creek, Santa Monica Bay. A hydrologic model was developed using EPA SWMM, calibrated for flow from water year 1998-2006 (NSE = 0.94; R2 = 0.94), and validated from water year 2007-2015 (NSE = 0.90; R2 = 0.93). This bacterial loading model was then linked to EPA SUSTAIN and a SCM bacterial removal script to simulate log removal of bacteria by various SCMs and predict bacterial concentrations in Ballona Creek. Preliminary results suggest small enhancements to SCMs that improve bacterial removal (<0.5 log removal) may offer large benefits to surface water quality and enable communities such as Los Angeles to meet their regulatory requirements.

  18. X-ray photoelectron spectroscopic evidence for bacteria-enhanced dissolution of hornblende

    Science.gov (United States)

    Kalinowski, B. E.; Liermann, L. J.; Brantley, S. L.; Barnes, A.; Pantano, C. G.

    2000-04-01

    An Arthrobacter species capable of extracting Fe from hornblende was isolated from a soil from the Adirondacks, NY (USA). This bacteria isolate, used in batch experiments with hornblende, accelerated the release of Fe from hornblende without measurably affecting Al release. The isolate produces both low molecular weight organic acids (LMWOA) and a catecholate siderophore. Polished hornblende (glass and crystal) discs were analyzed with X-ray photoelectron spectroscopy (XPS) before and after incubation with growing Arthrobacter sp. to investigate whether the bacteria caused a distinguishable chemical signature on the upper 100 Å of mineral surface. After removal of the arthrobacter grown on hornblende crystal or glass substrates using lysozyme, XPS revealed surface depletion of Fe for samples grown for several days in buffered (crystal) and unbuffered (crystal and glass) media. Fe/Si ratios of hornblende surfaces dissolved under biotic conditions are significantly lower than Fe/Si ratios on surfaces dissolved under abiotic conditions for similar amounts of time. Enhanced Fe release and the formation of Fe-depleted surfaces is inferred to be caused by catechol complexation at the mineral surface. Because natural siderophore was not isolated in sufficient quantities to run bacteria-free leaching experiments, parallel investigations were run with a commercially available siderophore (desferrioxamine B). Desferrioxamine B was observed to enhance release of Fe, Si, and Al from hornblende both with and without added bacteria. Formation of desferrioxamine-Fe surface complexes were probed by studying the multiple splitting and shift in intensities of the N 1s line analyzed by XPS on siderophore ± Fe on gold surfaces and siderophore + hornblende crystal surfaces. Based upon the observed formation of an hydroxamate (desferrioxamine) surface complex on hornblende, we infer that catecholate siderophores, such as those produced by the arthrobacter, also complex on the

  19. Optimization of Spore Forming Bacteria Flooding for Enhanced Oil Recovery in North Sea Chalk Reservoir

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Nielsen, Sidsel Marie; Eliasson Lantz, Anna

    2015-01-01

    .2-3.8 cm) during bacteria injection. Further seawater flooding after three days shut in period showed that permeability gradually increased in the first two sections of the core and started to decrease in the third section of the core (3.8-6.3 cm). Complete plugging was never observed in our experiments.......Little has been done to study microbial enhanced oil recovery (MEOR) in chalk reservoirs. The present study focused on core flooding experiments to see microbial plugging and its effect on oil recovery. A pressure tapped core holder with pressure ports at 1.2 cm, 3.8 cm, and 6.3 cm from the inlet...

  20. Surface-Enhanced Raman Scattering of Bacteria in Micro wells Constructed from Silver Nanoparticles

    International Nuclear Information System (INIS)

    Culha, M.; Yazici, M.M.; Kahraman, M.; Sahin, F.; Sesin Kocagoz, S.

    2012-01-01

    Whole bacterial cell characterization is critically important for fast bacterial identification. Surface-enhanced Raman scattering (SERS) is proven to be powerful technique to serve such a goal. In this study, the characterization of whole bacterial cells in the micro wells constructed from colloidal silver nanoparticles (AgNPs) with convective-assembly method is reported.- The proper size of the micro wells for the model bacteria, Escherichia coli and Staphylococcus cohnii, is determined to be 1.2μm from their electron microscopy images. A minimum dilution factor of 20 is necessary for the bacterial samples collected from growth media to diminish the bacterial aggregation to place the bacterial cells into the micro wells. The constructed micro well structures are tested for their bacterial SERS performance and compared to the SERS spectra obtained from the samples prepared with a simple mixing of bacteria and AgNPs for the same bacteria. The results indicate that micro well structures not only improve the spectral quality but also increase the reproducibility of the SERS spectra.

  1. Surface-Enhanced Raman Scattering of Bacteria in Microwells Constructed from Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mustafa Çulha

    2012-01-01

    Full Text Available Whole bacterial cell characterization is critically important for fast bacterial identification. Surface-enhanced Raman scattering (SERS is proven to be powerful technique to serve such a goal. In this study, the characterization of whole bacterial cells in the microwells constructed from colloidal silver nanoparticles (AgNPs with “convective-assembly” method is reported. The proper size of the microwells for the model bacteria, Escherichia coli and Staphylococcus cohnii, is determined to be 1.2 μm from their electron microscopy images. A minimum dilution factor of 20 is necessary for the bacterial samples collected from growth media to diminish the bacterial aggregation to place the bacterial cells into the microwells. The constructed microwell structures are tested for their bacterial SERS performance and compared to the SERS spectra obtained from the samples prepared with a simple mixing of bacteria and AgNPs for the same bacteria. The results indicate that microwell structures not only improve the spectral quality but also increase the reproducibility of the SERS spectra.

  2. Enhancing protein to extremely high content in photosynthetic bacteria during biogas slurry treatment.

    Science.gov (United States)

    Yang, Anqi; Zhang, Guangming; Meng, Fan; Lu, Pei; Wang, Xintian; Peng, Meng

    2017-12-01

    This work proposed a novel approach to achieve an extremely high protein content in photosynthetic bacteria (PSB) using biogas slurry as a culturing medium. The results showed the protein content of PSB could be enhanced strongly to 90% in the biogas slurry, which was much higher than reported microbial protein contents. The slurry was partially purified at the same time. Dark-aerobic was more beneficial than light-anaerobic condition for protein accumulation. High salinity and high ammonia of the biogas slurry were the main causes for protein enhancement. In addition, the biogas slurry provided a good buffer system for PSB to grow. The biosynthesis mechanism of protein in PSB was explored according to theoretical analysis. During biogas slurry treatment, the activities of glutamate synthase and glutamine synthetase were increased by 26.55%, 46.95% respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Surface-enhanced Raman scattering detection of bacteria on microarrays at single cell levels using silver nanoparticles

    International Nuclear Information System (INIS)

    Zhou, Haibo; Yang, Danting; Mircescu, Nicoleta E.; Ivleva, Natalia P.; Schwarzmeier, Kathrin; Niessner, Reinhard; Haisch, Christoph; Wieser, Andreas; Schubert, Sören

    2015-01-01

    We describe a method for the synthesis of SERS-active silver nanoparticles (AgNPs) directly on the surface of bacteria (bacteria-AgNPs), specifically of E. coli cells. This straightforward strategy allows for the sensitive determination of bacteria on a microarray platform. Antibodies were used as selective receptors on the microarray surface. The Raman signal of bacteria-AgNPs is about 10 times higher than that obtained previously with microarrays based on mixing bacteria and AgNPs (bacteria+AgNPs). The optimum SERS enhancement of bacteria-AgNPs is obtained under 633-nm laser excitation, and this most likely is due to the plasmonic interaction of aggregated AgNPs. The method allows for an identification and quantification even of single E. coli bacteria. In our perception, this straightforward approach represents a most valuable tool for the detection of E. coli and, conceivably, of other bacteria, and thus has a large potential in environmental monitoring, medical diagnosis, and in food safety and quality control. (author)

  4. Mass distribution and spatial organization of the linear bacterial motor of Spiroplasma citri R8A2.

    Science.gov (United States)

    Trachtenberg, Shlomo; Andrews, S Brian; Leapman, Richard D

    2003-03-01

    In the simple, helical, wall-less bacterial genus Spiroplasma, chemotaxis and motility are effected by a linear, contractile motor arranged as a flat cytoskeletal ribbon attached to the inner side of the membrane along the shortest helical line. With scanning transmission electron microscopy and diffraction analysis, we determined the hierarchical and spatial organization of the cytoskeleton of Spiroplasma citri R8A2. The structural unit appears to be a fibril, approximately 5 nm wide, composed of dimers of a 59-kDa protein; each ribbon is assembled from seven fibril pairs. The functional unit of the intact ribbon is a pair of aligned fibrils, along which pairs of dimers form tetrameric ring-like repeats. On average, isolated and purified ribbons contain 14 fibrils or seven well-aligned fibril pairs, which are the same structures observed in the intact cell. Scanning transmission electron microscopy mass analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified cytoskeletons indicate that the 59-kDa protein is the only constituent of the ribbons.

  5. Enhancement of Growth and Grain Yield of Rice in Nutrient Deficient Soils by Rice Probiotic Bacteria

    Institute of Scientific and Technical Information of China (English)

    Md Mohibul Alam KHAN; Effi HAQUE; Narayan Chandra PAUL; Md Abdul KHALEQUE; Saleh M. S. AL-GARNI; Mahfuzur RAHMAN; Md Tofazzal ISLAM

    2017-01-01

    Plant associated bacteria are promising alternatives to chemical fertilizers for plant growth and yield improvement in an eco-friendly manner. In this study, rice associated bacteria were isolated and assessed for mineral phosphate solubilization and indole-3-acetic acid (IAA) production activity in vitro. Six promising strains, which were tentatively identified as phylotaxon Pseudochrobactrum sp. (BRRh-1), Burkholderia sp. (BRRh-2), Burkholderia sp. (BRRh-3), Burkholderia sp. (BRRh-4), Pseudomonas aeruginosa (BRRh-5 and BRRh-6) based on their 16S rRNA gene phylogeny, exhibited significant phosphate solubilizing activity in National Botanical Research Institute phosphate growth medium, and BRRh-4 displayed the highest phosphate solubilizing activity, followed by BRRh-5. The pH of the culture broth declined, resulting in increase of growth rate of bacteria at pH 7, which might be due to organic acid secretion by the strains. In presence of L-tryptophan, five isolates synthesized IAA and the maximum IAA was produced by BRRh-2, followed by BRRh-1. Application of two most efficient phosphate solubilizing isolates BRRh-4 and BRRh-5 by root dipping (colonization) of seedling and spraying at the flowering stage significantly enhanced the growth and grain yield of rice variety BRRI dhan-29. Interestingly, application of both strains with 50% of recommended nitrogen, phosphorus and potassium fertilizers produced equivalent or higher grain yield of rice compared to the control grown with full recommended fertilizer doses, which suggests that these strains may have the potential to be used as bioinoculants for sustainable rice production.

  6. Enhanced bioremoval of lead by earthworm-Lumbricus terrestris co-cultivated with bacteria-Klebsiella variicola.

    Science.gov (United States)

    Das, Anamika; Osborne, Jabez W

    2017-10-01

    Lead is a toxic heavy metal having devastating effects on the environment. The current study was focussed on bioremoval of lead using earthworm and lead resistant bacteria. Earthworms were subjected to various concentrations of lead in the soil bioaugmented with lead resistant bacteria (VITMVCJ1) to enhance the uptake of lead from the contaminated soil. Significant increase was observed in the length and body weight of the earthworms supplemented with lead resistant bacteria. Similarly, there was a substantial increase in the locomotion rate of the earthworms treated with lead resistant bacteria in comparison with the control. The gut micro flora of bacterial treated earthworms had increased number of bacterial cells than the untreated earthworms. The histopathological studies revealed the toxic effects of lead on the gut of earthworms indicating severe damage in lead resistant bacteria untreated worms, whereas the cells were intact in lead resistant bacteria treated worms. COMET assay showed increased DNA damage with higher tail DNA percent in the untreated earthworms. Further, the colonisation of the bacteria supplemented, onto the gut region of earthworms was observed by scanning electron microscopy. Atomic absorption spectrophotometry indicated a fair 50% uptake of lead within the biomass of earthworm treated with lead resistant bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Rumen bacteria at work: bioaugmentation strategies to enhance biogas production from cow manure.

    Science.gov (United States)

    Ozbayram, E G; Akyol, Ç; Ince, B; Karakoç, C; Ince, O

    2018-02-01

    To investigate the effects of different bioaugmentation strategies for enhancing the biogas production from cow manure and evaluate microbial community patterns. Co-inoculation with cow rumen fluid and cow rumen-derived enriched microbial consortia was evaluated in anaerobic batch tests at 36°C and 41°C. Singular addition of both rumen fluid and enriched bioaugmentation culture had a promising enhancement on methane yields; however, the highest methane yield (311 ml CH 4 per gram VS at 41°C) was achieved when the anaerobic seed sludge was co-inoculated together with rumen fluid and enriched bioaugmentation culture. Bacterial community profiles were investigated by Ion PGM Platform, and specific lignocellulolytic bacteria dynamics in batch tests were assessed by qPCR. The temperature had minor effects on the abundance of bacterial community; in which Bacteroidetes and Firmicutes were the most abundant phyla in all digesters. Furthermore, Rikenellaceae, Clostridiaceae, Porphyromonadaceae, Bacteroidaceae and Ruminococcaceae played a crucial role during the anaerobic degradation of cow manure. There was an important impact of Firmicutes flavefaciens and Ruminococcus albus at 41°C, which in turn positively affected the methane production. The degree of enhancement in biogas production can be upgraded by the co-inoculation of rumen-derived bioaugmentation culture with anaerobic seed sludge with high methanogenic activity. A close look at the biotic interactions and their associations with abiotic factors might be valuable for evaluating rumen-related bioaugmentation applications. © 2017 The Society for Applied Microbiology.

  8. Motuporamine Derivatives as Antimicrobial Agents and Antibiotic Enhancers against Resistant Gram-Negative Bacteria.

    Science.gov (United States)

    Borselli, Diane; Blanchet, Marine; Bolla, Jean-Michel; Muth, Aaron; Skruber, Kristen; Phanstiel, Otto; Brunel, Jean Michel

    2017-02-01

    Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram-negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU-N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer-membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de-energization of the efflux pump rather than by direct interaction of the molecule with the pump. This suggests that depowering the efflux pump provides another strategy to address antibiotic resistance. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  9. Controller Parameter Optimization for Nonlinear Systems Using Enhanced Bacteria Foraging Algorithm

    Directory of Open Access Journals (Sweden)

    V. Rajinikanth

    2012-01-01

    Full Text Available An enhanced bacteria foraging optimization (EBFO algorithm-based Proportional + integral + derivative (PID controller tuning is proposed for a class of nonlinear process models. The EBFO algorithm is a modified form of standard BFO algorithm. A multiobjective performance index is considered to guide the EBFO algorithm for discovering the best possible value of controller parameters. The efficiency of the proposed scheme has been validated through a comparative study with classical BFO, adaptive BFO, PSO, and GA based controller tuning methods proposed in the literature. The proposed algorithm is tested in real time on a nonlinear spherical tank system. The real-time results show that, EBFO tuned PID controller gives a smooth response for setpoint tracking performance.

  10. Biogas production from brewery spent grain enhanced by bioaugmentation with hydrolytic anaerobic bacteria.

    Science.gov (United States)

    Čater, Maša; Fanedl, Lijana; Malovrh, Špela; Marinšek Logar, Romana

    2015-06-01

    Lignocellulosic substrates are widely available but not easily applied in biogas production due to their poor anaerobic degradation. The effect of bioaugmentation by anaerobic hydrolytic bacteria on biogas production was determined by the biochemical methane potential assay. Microbial biomass from full scale upflow anaerobic sludge blanket reactor treating brewery wastewater was a source of active microorganisms and brewery spent grain a model lignocellulosic substrate. Ruminococcus flavefaciens 007C, Pseudobutyrivibrio xylanivorans Mz5(T), Fibrobacter succinogenes S85 and Clostridium cellulovorans as pure and mixed cultures were used to enhance the lignocellulose degradation and elevate the biogas production. P. xylanivorans Mz5(T) was the most successful in elevating methane production (+17.8%), followed by the coculture of P. xylanivorans Mz5(T) and F. succinogenes S85 (+6.9%) and the coculture of C. cellulovorans and F. succinogenes S85 (+4.9%). Changes in microbial community structure were detected by fingerprinting techniques. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Bioaggregate of photo-fermentative bacteria for enhancing continuous hydrogen production in a sequencing batch photobioreactor.

    Science.gov (United States)

    Xie, Guo-Jun; Liu, Bing-Feng; Wang, Rui-Qing; Ding, Jie; Ren, Hong-Yu; Zhou, Xu; Ren, Nan-Qi

    2015-11-05

    Hydrogen recovery through solar-driven biomass conversion by photo-fermentative bacteria (PFB) has been regarded as a promising way for sustainable energy production. However, a considerable fraction of organic substrate was consumed for the growth of PFB as biocatalysts, furthermore, these PFB were continuously washed out from the photobioreactor in continuous operation because of their poor flocculation. In this work, PFB bioaggregate induced by L-cysteine was applied in a sequencing batch photobioreactor to enhance continuous hydrogen production and reduce biomass washout. The effects of the hydraulic retention time (HRT), influent concentration and light intensity on hydrogen production of the photobioreactor were investigated. The maximum hydrogen yield (3.35 mol H2/mol acetate) and production rate (1044 ml/l/d) were obtained at the HRT of 96 h, influent concentration of 3.84 g COD/l, and light intensity of 200 W/m(2). With excellent settling ability, biomass accumulated in the photobioreactor and reached 2.15 g/l under the optimum conditions. Structural analysis of bioaggregate showed that bacterial cells were covered and tightly linked together by extracellular polymeric substances, and formed a stable structure. Therefore, PFB bioaggregate induced by L-cysteine is an efficient strategy to improve biomass retention capacity of the photobioreactor and enhance hydrogen recovery efficiency from organic wastes.

  12. Bioaggregate of photo-fermentative bacteria for enhancing continuous hydrogen production in a sequencing batch photobioreactor

    Science.gov (United States)

    Xie, Guo-Jun; Liu, Bing-Feng; Wang, Rui-Qing; Ding, Jie; Ren, Hong-Yu; Zhou, Xu; Ren, Nan-Qi

    2015-11-01

    Hydrogen recovery through solar-driven biomass conversion by photo-fermentative bacteria (PFB) has been regarded as a promising way for sustainable energy production. However, a considerable fraction of organic substrate was consumed for the growth of PFB as biocatalysts, furthermore, these PFB were continuously washed out from the photobioreactor in continuous operation because of their poor flocculation. In this work, PFB bioaggregate induced by L-cysteine was applied in a sequencing batch photobioreactor to enhance continuous hydrogen production and reduce biomass washout. The effects of the hydraulic retention time (HRT), influent concentration and light intensity on hydrogen production of the photobioreactor were investigated. The maximum hydrogen yield (3.35 mol H2/mol acetate) and production rate (1044 ml/l/d) were obtained at the HRT of 96 h, influent concentration of 3.84 g COD/l, and light intensity of 200 W/m2. With excellent settling ability, biomass accumulated in the photobioreactor and reached 2.15 g/l under the optimum conditions. Structural analysis of bioaggregate showed that bacterial cells were covered and tightly linked together by extracellular polymeric substances, and formed a stable structure. Therefore, PFB bioaggregate induced by L-cysteine is an efficient strategy to improve biomass retention capacity of the photobioreactor and enhance hydrogen recovery efficiency from organic wastes.

  13. Genetic variability of Brazilian phytoplasma and spiroplasma isolated from maize plants Variabilidade genética de fitoplasma e espiroplasma isolados de plantas de milho no Brasil

    Directory of Open Access Journals (Sweden)

    Eliane Aparecida Gomes

    2004-01-01

    Full Text Available The objective of this work was to characterize the genetic variability of phytoplasma and Spiroplasma kunkelii isolated from maize plants showing symptoms of stunt collected from different Brazilian geographic regions. A DNA fragment of 500 base pairs (bp was amplified from the spiralin gene in S. kunkelii and one fragment of 1,200 bp was generated from 16S rDNA gene in phytoplasma. The partial sequences of the spiralin gene showed similarity of 98% among the isolates of S. kunkelii analyzed. These sequences were compared with the sequence of the spiralin gene from other Spiroplasma species deposited in the GenBank, resulting in a similarity varying from 76.9% to 88.1%. The 16S rDNA sequence from the phytoplasma were completely similar within the Brazilian isolates and showed up to 98% of the similarity with sequences already found from other phytoplasmas. A very narrow genetic variability was detected by these gene fragments within phytoplasma and Spiroplasma analyzed. However, other genomic regions with higher polymorphic levels shall be identified in order to better evaluate the genetic diversity within these microorganisms population.O objetivo deste trabalho foi caracterizar a variabilidade genética de isolados de fitoplasma e de Spiroplasma kunkelii obtidos de plantas de milho, apresentando sintomas de enfezamento, coletados em diferentes regiões do Brasil. Um fragmento de 500 pares de bases (pb do gene que codifica a espiralina de S. kunkelii foi amplificado e um produto de amplificação de 1.200 pb foi gerado a partir do gene 16S rDNA de fitoplasma. As seqüências parciais do gene da espiralina mostraram similaridade de 98% entre os isolados de S. kunkelii analisados. Essas seqüências foram comparadas com a seqüência do gene da espiralina de outras espécies de Spiroplasma depositadas no GenBank, resultando em similaridade variável entre 76,9% e 88,1%. As seqüências do gene 16S rDNA dos isolados de fitoplasma foram

  14. Label and label-free based surface-enhanced Raman scattering for pathogen bacteria detection: A review.

    Science.gov (United States)

    Liu, Yu; Zhou, Haibo; Hu, Ziwei; Yu, Guangxia; Yang, Danting; Zhao, Jinshun

    2017-08-15

    Rapid, accurate detection of pathogen bacteria is a highly topical research area for the sake of food safety and public health. Surface-enhanced Raman scattering (SERS) is being considered as a powerful and attractive technique for pathogen bacteria detection, due to its sensitivity, high speed, comparatively low cost, multiplexing ability and portability. This contribution aims to give a comprehensive overview of SERS as a technique for rapid detection of pathogen bacteria based on label and label-free strategies. A brief tutorial on SERS is given first of all. Then we summarize the recent trends and developments of label and label-free based SERS applied to detection of pathogen bacteria, including the relatively complete interpretation of SERS spectra. In addition, multifunctional SERS platforms for pathogen bacteria in matrix are discussed as well. Furthermore, an outlook of the work done and a perspective on the future directions of SERS as a reliable tool for real-time pathogen bacteria detection are given. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Bioreactor Study Employing Bacteria with Enhanced Activity toward Cyanobacterial Toxins Microcystins

    Directory of Open Access Journals (Sweden)

    Dariusz Dziga

    2014-08-01

    Full Text Available An important aim of white (grey biotechnology is bioremediation, where microbes are employed to remove unwanted chemicals. Microcystins (MCs and other cyanobacterial toxins are not industrial or agricultural pollutants; however, their occurrence as a consequence of human activity and water reservoir eutrophication is regarded as anthropogenic. Microbial degradation of microcystins is suggested as an alternative to chemical and physical methods of their elimination. This paper describes a possible technique of the practical application of the biodegradation process. The idea relies on the utilization of bacteria with a significantly enhanced MC-degradation ability (in comparison with wild strains. The cells of an Escherichia coli laboratory strain expressing microcystinase (MlrA responsible for the detoxification of MCs were immobilized in alginate beads. The degradation potency of the tested bioreactors was monitored by HPLC detection of linear microcystin LR (MC-LR as the MlrA degradation product. An open system based on a column filled with alginate-entrapped cells was shown to operate more efficiently than a closed system (alginate beads shaken in a glass container. The maximal degradation rate calculated per one liter of carrier was 219.9 µg h−1 of degraded MC-LR. A comparison of the efficiency of the described system with other biological and chemo-physical proposals suggests that this new idea presents several advantages and is worth investigating in future studies.

  16. Enhanced sulfamethoxazole degradation through ammonia oxidizing bacteria co-metabolism and fate of transformation products.

    Science.gov (United States)

    Kassotaki, Elissavet; Buttiglieri, Gianluigi; Ferrando-Climent, Laura; Rodriguez-Roda, Ignasi; Pijuan, Maite

    2016-05-01

    The occurrence of the widely-used antibiotic sulfamethoxazole (SFX) in wastewaters and surface waters has been reported in a large number of studies. However, the results obtained up-to-date have pointed out disparities in its removal. This manuscript explores the enhanced biodegradation potential of an enriched culture of Ammonia Oxidizing Bacteria (AOB) towards SFX. Several sets of batch tests were conducted to establish a link between SFX degradation and specific ammonia oxidation rate. The occurrence, degradation and generation of SFX and some of its transformation products (4-Nitro SFX, Desamino-SFX and N(4)-Acetyl-SFX) was also monitored. A clear link between the degradation of SFX and the nitrification rate was found, resulting in an increased SFX removal at higher specific ammonia oxidation rates. Moreover, experiments conducted under the presence of allylthiourea (ATU) did not present any removal of SFX, suggesting a connection between the AMO enzyme and SFX degradation. Long term experiments (up to 10 weeks) were also conducted adding two different concentrations (10 and 100 μg/L) of SFX in the influent of a partial nitrification sequencing batch reactor, resulting in up to 98% removal. Finally, the formation of transformation products during SFX degradation represented up to 32%, being 4-Nitro-SFX the most abundant. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Plant probiotic bacteria enhance the quality of fruit and horticultural crops

    Directory of Open Access Journals (Sweden)

    Alejandro Jiménez-Gómez

    2017-06-01

    Full Text Available The negative effects on the environment and human health caused by the current farming systems based on the overuse of chemical fertilizers have been reported in many studies. By contrast, bacterial inoculations produce positive effects on yields without causing this type of harm. Hence, during recent years, the commercialization of biofertilizers has been on the increase, and the number of companies and products available are expanding worldwide every year. In addition to the notable enhancement of crop production, many studies have shown how the application of bacteria has positive effects on food quality such as improved vitamin, flavonoid and antioxidant content, among other benefits. This advantage is interesting with respect to food that is consumed raw, such as fruits and many vegetables, as these bioactive molecules are maintained up until the moment the food is consumed. As regards this review focuses on the collection of studies that demonstrate that microorganisms can act as plant probiotics of fruit and horticultural crops, essential types of food that form part of a healthy diet.

  18. Barley β-Glucans-Containing Food Enhances Probiotic Performances of Beneficial Bacteria

    Directory of Open Access Journals (Sweden)

    Mattia P. Arena

    2014-02-01

    Full Text Available Currently, the majority of prebiotics in the market are derived from non-digestible oligosaccharides. Very few studies have focused on non-digestible long chain complex polysaccharides in relation to their potential as novel prebiotics. Cereals β-glucans have been investigated for immune-modulating properties and beneficial effects on obesity, cardiovascular diseases, diabetes, and cholesterol levels. Moreover, β-glucans have been reported to be highly fermentable by the intestinal microbiota in the caecum and colon, and can enhance both growth rate and lactic acid production of microbes isolated from the human intestine. In this work, we report the effects of food matrices containing barley β-glucans on growth and probiotic features of four Lactobacillus strains. Such matrices were able to improve the growth rate of the tested bacteria both in unstressed conditions and, importantly, after exposure to in vitro simulation of the digestive tract. Moreover, the effect of β-glucans-containing food on bacterial adhesion to enterocyte-like cells was analyzed and a positive influence on probiotic-enterocyte interaction was observed.

  19. Enhanced bioremediation of PAH-contaminated soil by immobilized bacteria with plant residue and biochar as carriers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Baoliang; Yuan, Miaoxin; Qian, Linbo [Zhejiang Univ., Hangzhou (China). Dept. of Environmental Science; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou (China)

    2012-10-15

    Polycyclic aromatic hydrocarbons (PAHs) are largely accumulated in soils in China. The immobilized-microorganism technique (IMT) is a potential approach for abating soil contamination with PAHs. However, few studies about the application of IMT to contaminated soil remediation were reported. Due to recalcitrance to decomposition, biochar application to soil may enhance soil carbon sequestration, but few studies on the application of biochars to remediation of contaminated soil were reported. In this study, we illustrated enhanced bioremediation of soil having a long history of PAH contamination by IMT using plant residues and biochars as carriers. Two PAH-degrading bacteria, Pseudomonas putida and an unidentified indigenous bacterium, were selected for IMT. The extractability and biodegradation of 15 PAHs in solution and an actual PAH-contaminated soil amended with immobilized-bacteria materials were investigated under different incubation periods. The effects of carriers and the molecular weight of PAHs on bioremediation efficiency were determined to illustrate their different bio-dissipation mechanisms of PAHs in soil. The IMT can considerably enhance the removal of PAHs. Carriers impose different effects on PAH bio-dissipation by amended soil with immobilized-bacteria, which can directly degrade the carrier-associated PAHs. The removal of PAHs from soil depended on PAH molecular weight and carrier types. Enhanced bio-dissipation by IMT was much stronger for 4- and 5-ring PAHs than for 3- and 6-ring ones in soil. Only P400 biochar-immobilized bacteria enhanced bio-dissipation of all PAHs in contaminated soil after a 90-day incubation. Biochar can promote bioremediation of contaminated soil as microbial carriers of IMT. It is vital to select an appropriate biochar as an immobilized carrier to stimulate biodegradation. It is feasible to use adsorption carriers with high sorptive capabilities to concentrate PAHs as well as microorganisms and thereby enhance

  20. Enhancing the auto-flocculation of photosynthetic bacteria to realize biomass recovery in brewery wastewater treatment.

    Science.gov (United States)

    Lu, Haifeng; Dong, Shan; Zhang, Guangming; Han, Ting; Zhang, Yuanhui; Li, Baoming

    2018-02-15

    Photosynthetic bacteria (PSB) wastewater treatment technology can simultaneously realize wastewater purification and biomass production. The produced biomass contains high value-added products, which can be used in medical and agricultural industry. However, because of the small size and high electronegativity, PSB are hard to be collected from wastewater, which hampers the commercialization of PSB-based industrial processes. Auto-flocculation is a low cost, energy saving, non-toxic biomass collection method for microbiology. In this work, the influence factors with their optimal levels and mechanism for enhancing the auto-flocculation of PSB were investigated in pure cultivation medium. Then PSB auto-flocculation performance in real brewery wastewater was probed. Results showed that Na + concentration, pH and light intensity were three crucial factors except the initial inoculum sizes and temperature. In the pure medium cultivation system, the optimal condition for PSB auto-flocculation was as follows: pH was 9.5, inoculum size was 420 mg l -1 , Na + concentration was 0.067 mol l -1 , light intensity was 5000 lux, temperature was 30°C. Under the optimal condition, the auto-flocculation ratio and biomass recovery reached 85.0% and 1488 mg l -1 , which improved by 1.67-fold and 2.14-fold compared with the PSB enrichment cultivation conditions, respectively. Mechanism analysis showed that the protein/polysaccharides ratio and absolute Zeta potential value had a liner relationship. For the brewery wastewater treatment, under the above optimal condition, the chemical oxygen demand removal reached 94.3% with the auto-flocculation ratio and biomass recovery of 89.6% and 1510 mg l -1 , which increased 2.75-fold and 2.77-fold, respectively.

  1. Population dynamics of bacteria involved in enhanced biological phosphorus removal in Danish wastewater treatment plants.

    Science.gov (United States)

    Mielczarek, Artur Tomasz; Nguyen, Hien Thi Thu; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

    2013-03-15

    The enhanced biological phosphorus removal (EBPR) process is increasingly popular as a sustainable method for removal of phosphorus (P) from wastewater. This study consisted of a comprehensive three-year investigation of the identity and population dynamics of polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in 28 Danish municipal wastewater treatment plants with nutrient removal. Fluorescence in situ hybridization was applied to quantify ten probe-defined populations of PAO and GAO that in total constituted a large fraction (30% on average) of the entire microbial community targeted by the EUBmix probes. Two PAO genera, Accumulibacter and Tetrasphaera, were very abundant in all EBPR plants (average of 3.7% and 27% of all bacteria, respectively), and their abundance was relatively stable in the Danish full-scale plants without clear temporal variations. GAOs were occasionally present in some plants (Competibacter in 11 plants, Defluviicoccus in 6 plants) and were consistent in only a few plants. This shows that these were not core species in the EBPR communities. The total GAO abundance was always lower than that of Accumulibacter. In plants without EBPR design, the abundance of PAO and GAO was significantly lower. Competibacter correlated in general with high fraction of industrial wastewater. In specific plants Accumulibacter correlated with high C/P ratio of the wastewater and Tetrasphaera with high organic loading. Interestingly, the relative microbial composition of the PAO/GAO species was unique to each plant over time, which gives a characteristic plant-specific "fingerprint". Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Implementing sponge physiological and genomic information to enhance the diversity of its culturable associated bacteria.

    Science.gov (United States)

    Lavy, Adi; Keren, Ray; Haber, Markus; Schwartz, Inbar; Ilan, Micha

    2014-02-01

    In recent years new approaches have emerged for culturing marine environmental bacteria. They include the use of novel culture media, sometimes with very low-nutrient content, and a variety of growth conditions such as temperature, oxygen levels, and different atmospheric pressures. These approaches have largely been neglected when it came to the cultivation of sponge-associated bacteria. Here, we used physiological and environmental conditions to reflect the environment of sponge-associated bacteria along with genomic data of the prominent sponge symbiont Candidatus Poribacteria sp. WGA-4E, to cultivate bacteria from the Red Sea sponge Theonella swinhoei. Designing culturing conditions to fit the metabolic needs of major bacterial taxa present in the sponge, through a combined use of diverse culture media compositions with aerobic and microaerophilic states, and addition of antibiotics, yielded higher diversity of the cultured bacteria and led to the isolation of novel sponge-associated and sponge-specific bacteria. In this work, 59 OTUs of six phyla were isolated. Of these, 22 have no close type strains at the species level (< 97% similarity of 16S rRNA gene sequence), representing novel bacteria species, and some are probably new genera and even families. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  3. Enhanced bioleaching on attachment of indigenous acidophilic bacteria to pyrite surface

    Science.gov (United States)

    Wi, D. W.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

    2012-04-01

    In recent years, bioleaching has been widely applied on an industrial scale due to the advantages of low cost and environment friendliness. The direct contact mechanism of bioleaching assumes the action of a metal sulfide-attached cell oxidizing the mineral by an enzyme system with oxygen to sulfate and metal cations. Fundamental surface properties of sulfide particles and leaching-bacteria in bioleaching play the key role in the efficiency of this process. The aim of this work is to investigate of direct contact bioleaching mechanism on pyrite through attachment properties between indigenous acidophilic bacteria and pyrite surfaces. The bacteria were obtained from sulfur hot springs, Hatchobaru thermal electricity plant in Japan. And pyrite was collected from mine waste from Gwang-yang abandoned gold mines, Korea. In XRD analyses of the pyrite, x-ray diffracted d-value belong to pyrite was observed. The indigenous acidophilic bacteria grew well in a solution and over the course of incubation pH decreased and Eh increased. In relation to a bacterial growth-curve, the lag phase was hardly shown while the exponential phase was very fast. Bioleaching experiment result was showed that twenty days after the indigenous acidophilic bacteria were inoculated to a pyrite-leaching medium, the bacterial sample had a greater concentration of Fe and Zn than within the control sample. In SEM-EDS analyses, rod-shaped bacteria and round-shaped microbes were well attached to the surface of pyrite. The size of the rod-shaped bacteria ranged from 1.05~1.10 ? to 4.01~5.38 ?. Round-shaped microbes were more than 3.0 ? in diameter. Paired cells of rod-shaped bacteria were attached to the surface of pyrite linearly.

  4. Combined use of vancomycin-modified Ag-coated magnetic nanoparticles and secondary enhanced nanoparticles for rapid surface-enhanced Raman scattering detection of bacteria.

    Science.gov (United States)

    Wang, Chongwen; Gu, Bing; Liu, Qiqi; Pang, Yuanfeng; Xiao, Rui; Wang, Shengqi

    2018-01-01

    Pathogenic bacteria have always been a significant threat to human health. The detection of pathogens needs to be rapid, accurate, and convenient. We present a sensitive surface-enhanced Raman scattering (SERS) biosensor based on the combination of vancomycin-modified Ag-coated magnetic nanoparticles (Fe 3 O 4 @Ag-Van MNPs) and Au@Ag nanoparticles (NPs) that can effectively capture and discriminate bacterial pathogens from solution. The high-performance Fe 3 O 4 @Ag MNPs were modified with vancomycin and used as bacteria capturer for magnetic separation and enrichment. The modified MNPS were found to exhibit strong affinity with a broad range of Gram-positive and Gram-negative bacteria. After separating and rinsing bacteria, Fe 3 O 4 @Ag-Van MNPs and Au@Ag NPs were synergistically used to construct a very large number of hot spots on bacteria cells, leading to ultrasensitive SERS detection. The dominant merits of our dual enhanced strategy included high bacterial-capture efficiency (>65%) within a wide pH range (pH 3.0-11.0), a short assay time (<30 min), and a low detection limit (5×10 2 cells/mL). Moreover, the spiked tests show that this method is still valid in milk and blood samples. Owing to these capabilities, the combined system enabled the sensitive and specific discrimination of different pathogens in complex solution, as verified by its detection of Gram-positive bacterium Escherichia coli , Gram-positive bacterium Staphylococcus aureus , and methicillin-resistant S. aureus . This method has great potential for field applications in food safety, environmental monitoring, and infectious disease diagnosis.

  5. Mycorrhization between Cistus ladanifer L. and Boletus edulis Bull is enhanced by the mycorrhiza helper bacteria Pseudomonas fluorescens Migula.

    Science.gov (United States)

    Mediavilla, Olaya; Olaizola, Jaime; Santos-del-Blanco, Luis; Oria-de-Rueda, Juan Andrés; Martín-Pinto, Pablo

    2016-02-01

    Boletus edulis Bull. is one of the most economically and gastronomically valuable fungi worldwide. Sporocarp production normally occurs when symbiotically associated with a number of tree species in stands over 40 years old, but it has also been reported in 3-year-old Cistus ladanifer L. shrubs. Efforts toward the domestication of B. edulis have thus focused on successfully generating C. ladanifer seedlings associated with B. edulis under controlled conditions. Microorganisms have an important role mediating mycorrhizal symbiosis, such as some bacteria species which enhance mycorrhiza formation (mycorrhiza helper bacteria). Thus, in this study, we explored the effect that mycorrhiza helper bacteria have on the efficiency and intensity of the ectomycorrhizal symbiosis between C. ladanifer and B. edulis. The aim of this work was to optimize an in vitro protocol for the mycorrhizal synthesis of B. edulis with C. ladanifer by testing the effects of fungal culture time and coinoculation with the helper bacteria Pseudomonas fluorescens Migula. The results confirmed successful mycorrhizal synthesis between C. ladanifer and B. edulis. Coinoculation of B. edulis with P. fluorescens doubled within-plant mycorrhization levels although it did not result in an increased number of seedlings colonized with B. edulis mycorrhizae. B. edulis mycelium culture time also increased mycorrhization levels but not the presence of mycorrhizae. These findings bring us closer to controlled B. edulis sporocarp production in plantations.

  6. Enhance wastewater biological treatment through the bacteria induced graphene oxide hydrogel.

    Science.gov (United States)

    Shen, Liang; Jin, Ziheng; Wang, Dian; Wang, Yuanpeng; Lu, Yinghua

    2018-01-01

    The interaction between bacteria and graphene-family materials like pristine graphene, graphene oxide (GO) and reduced graphene oxide (rGO) is such an elusive issue that its implication in environmental biotechnology is unclear. Herein, two kinds of self-assembled bio-rGO-hydrogels (BGHs) were prepared by cultivating specific Shewanella sp. strains with GO solution for the first time. The microscopic examination by SEM, TEM and CLSM indicated a porous 3D structure of BGHs, in which live bacteria firmly anchored and extracellular polymeric substances (EPS) abundantly distributed. Spectra of XRD, FTIR, XPS and Raman further proved that GO was reduced to rGO by bacteria along with the gelation process, which suggests a potential green technique to produce graphene. Based on the characterization results, four mechanisms for the BGH formation were proposed, i.e., stacking, bridging, rolling and cross-linking of rGO sheets, through the synergistic effect of activities and EPS from special bacteria. More importantly, the BGHs obtained in this study were found able to achieve unique cleanup performance that the counterpart free bacteria could not fulfill, as exemplified in Congo red decolorization and Cr(VI) bioreduction. These findings therefore enlighten a prospective application of graphene materials for the biological treatment of wastewaters in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Enhanced fatty acid production in engineered chemolithoautotrophic bacteria using reduced sulfur compounds as energy sources

    DEFF Research Database (Denmark)

    Beller, Harry R.; Zhou, Peng; Jewell, Talia N.M.

    2016-01-01

    Chemolithoautotrophic bacteria that oxidize reduced sulfur compounds, such as H2S, while fixing CO2 are an untapped source of renewable bioproducts from sulfide-laden waste, such as municipal wastewater. In this study, we report engineering of the chemolithoautotrophic bacterium Thiobacillus...

  8. Enhanced biohydrogen production from corn stover by the combination of Clostridium cellulolyticum and hydrogen fermentation bacteria.

    Science.gov (United States)

    Zhang, Shou-Chi; Lai, Qi-Heng; Lu, Yuan; Liu, Zhi-Dan; Wang, Tian-Min; Zhang, Chong; Xing, Xin-Hui

    2016-10-01

    Hydrogen was produced from steam-exploded corn stover by using a combination of the cellulolytic bacterium Clostridium cellulolyticum and non-cellulolytic hydrogen-producing bacteria. The highest hydrogen yield of the co-culture system with C. cellulolyticum and Citrobacter amalonaticus reached 51.9 L H2/kg total solid (TS). The metabolites from the co-culture system were significantly different from those of the mono-culture systems. Formate, which inhibits the growth of C. cellulolyticum, could be consumed by the hydrogen-evolving bacteria, and transformed into hydrogen. Glucose and xylose were released from corn stover via hydrolysis by C. cellulolyticum and were quickly utilized in dark fermentation with the co-cultured hydrogen-producing bacteria. Because the hydrolysis of corn stover by C. cellulolyticum was much slower than the utilization of glucose and xylose by the hydrogen-evolving bacteria, the sugar concentrations were always maintained at low levels, which favored a high hydrogen molar yield. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  9. Enhanced biodegradation of Pina Cuban crude oil by a culture of mixed marine bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, I.N.; Perigo, E. [Ministry of Science. Inst. of Oceanography, La Habana (Cuba); Bergueiro, J.R.; Pita, A.; Mayol, M.A. [Balearic Island Univ., Palma de Mallorca, Islas Baleares (Spain); Navarro, A. [Ministry of Industry, Oil Research Center, La Habana (Cuba)

    1998-09-01

    The ability of a mixed marine bacteria culture to degrade Pina Cuban crude oil in the presence of nutrients and sea water was studied. Laboratory experiments were conducted in flasks with 100 ml of saline liquid containing 1 per cent crude. The flasks were inoculated with marine bacteria (IDO-225, IDO-226, and IDO-229) at a final concentration of 10{sup 6} cell/ml. The cultures were grown at 29 degrees C for 21 days. Bacterial growth, and surface and interfacial tension were measured after 5, 13 and 21 days. Results showed that the marine bacteria were effective in accelerating the biodegradation process of Pina Cuban oil. The efficiency of the process increased when nutrients were added to the system. This biopreparation also accelerated emulsification of the oil without any negative effects to the natural microbiota. The biological oxygen demand at five days and at the end of the experiment was determined. The biodegradation constant and the biochemical stabilization constant were also measured. 14 refs., 5 tabs., 4 figs.

  10. Enhanced biodegradation of Pina Cuban crude oil by a culture of mixed marine bacteria

    International Nuclear Information System (INIS)

    Joseph, I.N.; Perigo, E.; Bergueiro, J.R.; Pita, A.; Mayol, M.A.; Navarro, A.

    1998-01-01

    The ability of a mixed marine bacteria culture to degrade Pina Cuban crude oil in the presence of nutrients and sea water was studied. Laboratory experiments were conducted in flasks with 100 ml of saline liquid containing 1 per cent crude. The flasks were inoculated with marine bacteria (IDO-225, IDO-226, and IDO-229) at a final concentration of 10 6 cell/ml. The cultures were grown at 29 degrees C for 21 days. Bacterial growth, and surface and interfacial tension were measured after 5, 13 and 21 days. Results showed that the marine bacteria were effective in accelerating the biodegradation process of Pina Cuban oil. The efficiency of the process increased when nutrients were added to the system. This biopreparation also accelerated emulsification of the oil without any negative effects to the natural microbiota. The biological oxygen demand at five days and at the end of the experiment was determined. The biodegradation constant and the biochemical stabilization constant were also measured. 14 refs., 5 tabs., 4 figs

  11. Combined use of alkane-degrading and plant growth-promoting bacteria enhanced phytoremediation of diesel contaminated soil.

    Science.gov (United States)

    Tara, Nain; Afzal, Muhammad; Ansari, Tariq M; Tahseen, Razia; Iqbal, Samina; Khan, Qaiser M

    2014-01-01

    Inoculation of plants with pollutant-degrading and plant growth-promoting microorganisms is a simple strategy to enhance phytoremediation activity. The objective of this study was to determine the effect of inoculation of different bacterial strains, possessing alkane-degradation and 1-amino-cyclopropane-1 -carboxylic acid (ACC) deaminase activity, on plant growth and phytoremediation activity. Carpet grass (Axonopus affinis) was planted in soil spiked with diesel (1% w/w) for 90 days and inoculated with different bacterial strains, Pseudomonas sp. ITRH25, Pantoea sp. BTRH79 and Burkholderia sp. PsJN, individually and in combination. Generally, bacterial application increased total numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere ofcarpet grass, plant biomass production, hydrocarbon degradation and reduced genotoxicity. Bacterial strains possessing different beneficial traits affect plant growth and phytoremediation activity in different ways. Maximum bacterial population, plant biomass production and hydrocarbon degradation were achieved when carpet grass was inoculated with a consortium of three strains. Enhanced plant biomass production and hydrocarbon degradation were associated with increased numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere of carpet grass. The present study revealed that the combined use of different bacterial strains, exhibiting different beneficial traits, is a highly effective strategy to improve plant growth and phytoremediation activity.

  12. Urinary tract infection (UTI) multi-bacteria multi-antibiotic testing using surface enhanced Raman spectroscopy (SERS)

    Science.gov (United States)

    Hadjigeorgiou, Katerina; Kastanos, Evdokia; Pitris, Costas

    2013-02-01

    Antibiotic resistance is a major health care problem mostly caused by the inappropriate use of antibiotics. At the root of the problem lies the current method for determination of bacterial susceptibility to antibiotics which requires overnight cultures. Physicians suspecting an infection usually prescribe an antibiotic without waiting for the results. This practice aggravates the problem of bacterial resistance. In this work, a rapid method of diagnosis and antibiogram for a bacterial infection was developed using Surface Enhanced Raman Spectroscopy (SERS) with silver nanoparticles. SERS spectra of three species of gram negative bacteria, Escherichia coli, Proteus spp., and Klebsiella spp. were obtained after 0 and 4 hour exposure to the seven different antibiotics. Even though the concentration of bacteria was low (2x105 cfu/ml), species classification was achieved with 94% accuracy using spectra obtained at 0 hours. Sensitivity or resistance to antibiotics was predicted with 81%-100% accuracy from spectra obtained after 4 hours of exposure to the different antibiotics. With the enhancement provided by SERS, the technique can be applied directly to urine or blood samples, bypassing the need for overnight cultures. This technology can lead to the development of rapid methods of diagnosis and antibiogram for a variety of bacterial infections.

  13. Multi-bacteria multi-antibiotic testing using surface enhanced Raman spectroscopy (SERS) for urinary tract infection (UTI) diagnosis

    Science.gov (United States)

    Hadjigeorgiou, Katerina; Kastanos, Evdokia; Pitris, Costas

    2013-06-01

    The inappropriate use of antibiotics leads to antibiotic resistance, which is a major health care problem. The current method for determination of bacterial susceptibility to antibiotics requires overnight cultures. However most of the infections cannot wait for the results to receive treatment, so physicians administer general spectrum antibiotics. This results in ineffective treatments and aggravates the rising problem of antibiotic resistance. In this work, a rapid method for diagnosis and antibiogram for a bacterial infection was developed using Surface Enhanced Raman Spectroscopy (SERS) with silver nanoparticles. The advantages of this novel method include its rapidness and efficiency which will potentially allow doctors to prescribe the most appropriate antibiotic for an infection. SERS spectra of three species of gram negative bacteria, Escherichia coli, Proteus spp., and Klebsiella spp. were obtained after 0 and 4 hour exposure to the seven different antibiotics. Bacterial strains were diluted in order to reach the concentration of (2x105 cfu/ml), cells/ml which is equivalent to the minimum concentration found in urine samples from UTIs. Even though the concentration of bacteria was low, species classification was achieved with 94% accuracy using spectra obtained at 0 hours. Sensitivity or resistance to antibiotics was predicted with 81%-100% accuracy from spectra obtained after 4 hours of exposure to the different antibiotics. This technique can be applied directly to urine samples, and with the enhancement provided by SERS, this method has the potential to be developed into a rapid method for same day UTI diagnosis and antibiogram.

  14. Application of droplet digital PCR for quantitative detection of Spiroplasma citri in comparison with real time PCR.

    Directory of Open Access Journals (Sweden)

    Yogita Maheshwari

    Full Text Available Droplet digital polymerase chain reaction (ddPCR is a method for performing digital PCR that is based on water-oil emulsion droplet technology. It is a unique approach to measure the absolute copy number of nucleic acid targets without the need of external standards. This study evaluated the applicability of ddPCR as a quantitative detection tool for the Spiroplasma citri, causal agent of citrus stubborn disease (CSD in citrus. Two sets of primers, SP1, based on the spiral in housekeeping gene, and a multicopy prophage gene, SpV1 ORF1, were used to evaluate ddPCR in comparison with real time (quantitative PCR (qPCR for S. citri detection in citrus tissues. Standard curve analyses on tenfold dilution series showed that both ddPCR and qPCR exhibited good linearity and efficiency. However, ddPCR had a tenfold greater sensitivity than qPCR and accurately quantified up to one copy of spiralin gene. Receiver operating characteristic analysis indicated that the ddPCR methodology was more robust for diagnosis of CSD and the area under the curve was significantly broader compared to qPCR. Field samples were used to validate ddPCR efficacy and demonstrated that it was equal or better than qPCR to detect S. citri infection in fruit columella due to a higher pathogen titer. The ddPCR assay detected both the S. citri spiralin and the SpV1 ORF1 targets quantitatively with high precision and accuracy compared to qPCR assay. The ddPCR was highly reproducible and repeatable for both the targets and showed higher resilience to PCR inhibitors in citrus tissue extract for the quantification of S. citri compare to qPCR.

  15. Parasitic infection improves survival from septic peritonitis by enhancing mast cell responses to bacteria in mice.

    Directory of Open Access Journals (Sweden)

    Rachel E Sutherland

    Full Text Available Mammals are serially infected with a variety of microorganisms, including bacteria and parasites. Each infection reprograms the immune system's responses to re-exposure and potentially alters responses to first-time infection by different microorganisms. To examine whether infection with a metazoan parasite modulates host responses to subsequent bacterial infection, mice were infected with the hookworm-like intestinal nematode Nippostrongylus brasiliensis, followed in 2-4 weeks by peritoneal injection of the pathogenic bacterium Klebsiella pneumoniae. Survival from Klebsiella peritonitis two weeks after parasite infection was better in Nippostrongylus-infected animals than in unparasitized mice, with Nippostrongylus-infected mice having fewer peritoneal bacteria, more neutrophils, and higher levels of protective interleukin 6. The improved survival of Nippostrongylus-infected mice depends on IL-4 because the survival benefit is lost in mice lacking IL-4. Because mast cells protect mice from Klebsiella peritonitis, we examined responses in mast cell-deficient Kit(W-sh/Kit(W-sh mice, in which parasitosis failed to improve survival from Klebsiella peritonitis. However, adoptive transfer of cultured mast cells to Kit(W-sh/Kit(W-sh mice restored survival benefits of parasitosis. These results show that recent infection with Nippostrongylus brasiliensis protects mice from Klebsiella peritonitis by modulating mast cell contributions to host defense, and suggest more generally that parasitosis can yield survival advantages to a bacterially infected host.

  16. Enhanced crude oil biodegradative potential of natural phytoplankton-associated hydrocarbonoclastic bacteria.

    Science.gov (United States)

    Thompson, Haydn; Angelova, Angelina; Bowler, Bernard; Jones, Martin; Gutierrez, Tony

    2017-07-01

    Phytoplankton have been shown to harbour a diversity of hydrocarbonoclastic bacteria (HCB), yet it is not understood how these phytoplankton-associated HCB would respond in the event of an oil spill at sea. Here, we assess the diversity and dynamics of the bacterial community associated with a natural population of marine phytoplankton under oil spill-simulated conditions, and compare it to that of the free-living (non phytoplankton-associated) bacterial community. While the crude oil severely impacted the phytoplankton population and was likely conducive to marine oil snow formation, analysis of the MiSeq-derived 16S rRNA data revealed dramatic and differential shifts in the oil-amended communities that included blooms of recognized HCB (e.g., Thalassospira, Cycloclasticus), including putative novel phyla, as well as other groups with previously unqualified oil-degrading potential (Olleya, Winogradskyella, and members of the inconspicuous BD7-3 phylum). Notably, the oil biodegradation potential of the phytoplankton-associated community exceeded that of the free-living community, and it showed a preference to degrade substituted and non-substituted polycyclic aromatic hydrocarbons. Our study provides evidence of compartmentalization of hydrocarbon-degrading capacity in the marine water column, wherein HCB associated with phytoplankton are better tuned to degrading crude oil hydrocarbons than that by the community of planktonic free-living bacteria. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. The concomitant use of indigenous soil bacteria and fungi to enhance the bioremediation of refinery waste

    Energy Technology Data Exchange (ETDEWEB)

    Campos Carvalho, F.J.P. de [Universidade Federal do Parana, Curitiba (Brazil)

    2001-07-01

    Usually, the use of indigenous soil bacteria for the remediation of petroleum-contaminated soils was restricted to the biodegradation of low-molecular weight petroleum hydrocarbons such as gasoline, diesel, fuel oil and jet fuel. The advantage of using indigenous microorganisms is the minimization of the impact of the treatment on the microbial diversity. As a rule,these techniques are also well accepted by the public. Other studies have shown that fungi is successful for the bioremediation of heavier-weight contaminants. The concomitant transformation of low-molecular weight and heavier recalcitrant oil fractions to inorganic and humic form can be accomplished with the concomitant action of bacteria and fungi. The development of a soil biotreatment program using this concomitant technique was performed by PETROBRAS Petroleo Brasileiro S.A. - Refinaria Presidente Getulio Vargas in conjunction with the Universidade Federal do Parana. It resulted in a full-scale technology that allows the degradation of oil waste. Approximately two years of treatment are required to achieve the desired results. The use of standard analytical methods and bioindicators used on the treated soil indicated that the treated soil met the standards for agricultural soil quality. A recent oil spill occurred in Araucaria, Brazil and a bioremediation area was inoculated, and to date the results prove the beneficial effects to be derived from the use of inoculation. Some results were presented in table format. 3 tabs.

  18. Delayed accumulation of intestinal coliform bacteria enhances life span and stress resistance in Caenorhabditis elegans fed respiratory deficient E. coli.

    Science.gov (United States)

    Gomez, Fernando; Monsalve, Gabriela C; Tse, Vincent; Saiki, Ryoichi; Weng, Emily; Lee, Laura; Srinivasan, Chandra; Frand, Alison R; Clarke, Catherine F

    2012-12-20

    Studies with the nematode model Caenorhabditis elegans have identified conserved biochemical pathways that act to modulate life span. Life span can also be influenced by the composition of the intestinal microbiome, and C. elegans life span can be dramatically influenced by its diet of Escherichia coli. Although C. elegans is typically fed the standard OP50 strain of E. coli, nematodes fed E. coli strains rendered respiratory deficient, either due to a lack coenzyme Q or the absence of ATP synthase, show significant life span extension. Here we explore the mechanisms accounting for the enhanced nematode life span in response to these diets. The intestinal load of E. coli was monitored by determination of worm-associated colony forming units (cfu/worm or coliform counts) as a function of age. The presence of GFP-expressing E. coli in the worm intestine was also monitored by fluorescence microscopy. Worms fed the standard OP50 E. coli strain have high cfu and GFP-labeled bacteria in their guts at the L4 larval stage, and show saturated coliform counts by day five of adulthood. In contrast, nematodes fed diets of respiratory deficient E. coli lacking coenzyme Q lived significantly longer and failed to accumulate bacteria within the lumen at early ages. Animals fed bacteria deficient in complex V showed intermediate coliform numbers and were not quite as long-lived. The results indicate that respiratory deficient Q-less E. coli are effectively degraded in the early adult worm, either at the pharynx or within the intestine, and do not accumulate in the intestinal tract until day ten of adulthood. The findings of this study suggest that the nematodes fed the respiratory deficient E. coli diet live longer because the delay in bacterial colonization of the gut subjects the worms to less stress compared to worms fed the OP50 E. coli diet. This work suggests that bacterial respiration can act as a virulence factor, influencing the ability of bacteria to colonize and

  19. Delayed accumulation of intestinal coliform bacteria enhances life span and stress resistance in Caenorhabditis elegans fed respiratory deficient E. coli

    Directory of Open Access Journals (Sweden)

    Gomez Fernando

    2012-12-01

    Full Text Available Abstract Background Studies with the nematode model Caenorhabditis elegans have identified conserved biochemical pathways that act to modulate life span. Life span can also be influenced by the composition of the intestinal microbiome, and C. elegans life span can be dramatically influenced by its diet of Escherichia coli. Although C. elegans is typically fed the standard OP50 strain of E. coli, nematodes fed E. coli strains rendered respiratory deficient, either due to a lack coenzyme Q or the absence of ATP synthase, show significant life span extension. Here we explore the mechanisms accounting for the enhanced nematode life span in response to these diets. Results The intestinal load of E. coli was monitored by determination of worm-associated colony forming units (cfu/worm or coliform counts as a function of age. The presence of GFP-expressing E. coli in the worm intestine was also monitored by fluorescence microscopy. Worms fed the standard OP50 E. coli strain have high cfu and GFP-labeled bacteria in their guts at the L4 larval stage, and show saturated coliform counts by day five of adulthood. In contrast, nematodes fed diets of respiratory deficient E. coli lacking coenzyme Q lived significantly longer and failed to accumulate bacteria within the lumen at early ages. Animals fed bacteria deficient in complex V showed intermediate coliform numbers and were not quite as long-lived. The results indicate that respiratory deficient Q-less E. coli are effectively degraded in the early adult worm, either at the pharynx or within the intestine, and do not accumulate in the intestinal tract until day ten of adulthood. Conclusions The findings of this study suggest that the nematodes fed the respiratory deficient E. coli diet live longer because the delay in bacterial colonization of the gut subjects the worms to less stress compared to worms fed the OP50 E. coli diet. This work suggests that bacterial respiration can act as a virulence factor

  20. Enhanced degradation activity by endophytic bacteria of plants growing in hydrocarbon contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, L.; Germida, J.J. [Saskatchewan Univ., Saskatoon, SK (Canada); Greer, C.W. [National Research Council of Canada, Montreal, PQ (Canada). Biotechnology Research Inst.

    2006-07-01

    The feasibility of using phytoremediation for cleaning soils contaminated with petroleum hydrocarbons was discussed. Petroleum hydrocarbons are problematic because of their toxicity, mobility and persistence in the environment. Appropriate clean-up methods are needed, given that 60 per cent of Canada's contaminated sites contain these compounds. Phytoremediation is an in situ biotechnology in which plants are used to facilitate contaminant removal. The approach relies on a synergistic relationship between plants and their root-associated microbial communities. Previous studies on phytoremediation have focussed on rhizosphere communities. However, it is believed that endophytic microbes may also play a vital role in organic contaminant degradation. This study investigated the structural and functional dynamics of both rhizosphere and endophytic microbial communities of plants from a phytoremediation field site in south-eastern Saskatchewan. The former flare pit contains up to 10,000 ppm of F3 to F4 hydrocarbon fractions. Root samples were collected from tall wheatgrass, wild rye, saltmeadow grass, perennial ryegrass, and alfalfa. Culture-based and culture-independent methods were used to evaluate the microbial communities associated with these roots. Most probable number assays showed that the rhizosphere communities contained more n-hexadecane, diesel fuel, and PAH degraders. However, mineralization assays with 14C labelled n-hexadecane, naphthalene, and phenanthrene showed that endophytic communities had more degradation activities per standardized initial degrader populations. Total community DNA samples taken from bulk, rhizosphere, and endophytic samples, were analyzed by denaturing gradient gel electrophoresis. It was shown that specific bacteria increased in endophytic communities compared to rhizosphere communities. It was suggested plants may possibly recruit specific bacteria in response to hydrocarbon contamination, thereby increasing degradation

  1. Investigation on behavior of bacteria in reservoir for microbial enhanced oil recovery; Biseibutsuho (MEOR) no tameno yusonai saikin katsudo ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, K.; Tanaka, S.; Otsuka, M.; Nakaya, K. [Kansai Research Institute, Kyoto (Japan). Lifescience Research Center; Maezumi, S.; Yazawa, N. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center; Hong, C.; Chida, T.; Enomoto, H. [Tohoku University, Miyagi (Japan). Graduate School of Engineering

    2000-07-01

    Behavior of bacteria activated in reservoir though molasses-injection-tests, was investigated using the restriction fragment length polymorphism analysis with the polymerase chain reaction (PCR-RFLP) method, for elucidating potential bacteria to suppress in situ growth of microbes to be injected into the reservoir in the microbial enhanced oil recovery (MEOR) process. As a result, some bacteria belonging to Enterobacteriaceae species or their close relative species were grown predominantly in the reservoir, among bacteria inhibiting in the ground-water. The foregoing indicates that behavior of these bacteria in reservoir must be taken into consideration when giving a full account of behavior of microbes to be injected into the reservoir to put the MEOR process into operation. Potential proliferation using molasses to activate those bacteria was also estimated on the laboratory tests, to clarify the growth of microbes to be injected into the reservoir to operate the MEOR process. In consequence, it became clear that these bacteria have a potential growth exceeding 10{sup 8} CFU/ml, utilizing molasses. These facts indicated that microbes to be injected into the reservoir at the MEOR field tests are necessary to grow more excellently than bacteria inhabiting in the ground-water. In addition, as flow, the injection fluid is influenced by reservoir heterogeneity caused by injection of molasses, it was inferred that microbes to be injected into the reservoir at the MEOR field process are also necessary to grow more remarkably than bacteria inhabiting in the reservoir brine at high permeability zones and bacteria inhabiting in the reservoir rock. Furthermore, the results of the functional testing for MEOR conducted in the presence of bacteria activated through molasses-injection-tests indicated the importance of effective use of microbes to be injected, taking into account the characteristics of the reservoir and function for MEOR of those microbes. (author)

  2. Enhanced reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide

    International Nuclear Information System (INIS)

    Li, F.B.; Li, X.M.; Zhou, S.G.; Zhuang, L.; Cao, F.; Huang, D.Y.; Xu, W.; Liu, T.X.; Feng, C.H.

    2010-01-01

    The transformation of DDT was studied in an anaerobic system of dissimilatory iron-reducing bacteria (Shewanella decolorationis S12) and iron oxide (α-FeOOH). The results showed that S. decolorationis could reduce DDT into DDD, and DDT transformation rate was accelerated by the presence of α-FeOOH. DDD was observed as the primary transformation product, which was demonstrated to be transformed in the abiotic system of Fe 2+ + α-FeOOH and the system of DIRB + α-FeOOH. The intermediates of DDMS and DBP were detected after 9 months, likely suggesting that reductive dechlorination was the main dechlorination pathway of DDT in the iron-reducing system. The enhanced reductive dechlorination of DDT was mainly due to biogenic Fe(II) sorbed on the surface of α-FeOOH, which can serve as a mediator for the transformation of DDT. This study demonstrated the important role of DIRB and iron oxide on DDT and DDD transformation under anaerobic iron-reducing environments. - This is the first case reporting the reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide.

  3. Enhanced reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide

    Energy Technology Data Exchange (ETDEWEB)

    Li, F.B., E-mail: cefbli@soil.gd.c [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Li, X.M. [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Zhou, S.G.; Zhuang, L. [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Cao, F. [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Huang, D.Y.; Xu, W.; Liu, T.X. [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Feng, C.H. [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China)

    2010-05-15

    The transformation of DDT was studied in an anaerobic system of dissimilatory iron-reducing bacteria (Shewanella decolorationis S12) and iron oxide (alpha-FeOOH). The results showed that S. decolorationis could reduce DDT into DDD, and DDT transformation rate was accelerated by the presence of alpha-FeOOH. DDD was observed as the primary transformation product, which was demonstrated to be transformed in the abiotic system of Fe{sup 2+} + alpha-FeOOH and the system of DIRB + alpha-FeOOH. The intermediates of DDMS and DBP were detected after 9 months, likely suggesting that reductive dechlorination was the main dechlorination pathway of DDT in the iron-reducing system. The enhanced reductive dechlorination of DDT was mainly due to biogenic Fe(II) sorbed on the surface of alpha-FeOOH, which can serve as a mediator for the transformation of DDT. This study demonstrated the important role of DIRB and iron oxide on DDT and DDD transformation under anaerobic iron-reducing environments. - This is the first case reporting the reductive dechlorination of DDT in an anaerobic system of dissimilatory iron-reducing bacteria and iron oxide.

  4. Microbial enhanced heavy oil recovery by the aid of inhabitant spore-forming bacteria: an insight review.

    Science.gov (United States)

    Shibulal, Biji; Al-Bahry, Saif N; Al-Wahaibi, Yahya M; Elshafie, Abdulkader E; Al-Bemani, Ali S; Joshi, Sanket J

    2014-01-01

    Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR) is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s) were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers.

  5. Microbial Enhanced Heavy Oil Recovery by the Aid of Inhabitant Spore-Forming Bacteria: An Insight Review

    Directory of Open Access Journals (Sweden)

    Biji Shibulal

    2014-01-01

    Full Text Available Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers.

  6. Enhanced mucosal delivery of antigen with cell wall mutants of lactic acid bacteria.

    Science.gov (United States)

    Grangette, Corinne; Müller-Alouf, Heide; Hols, Pascal; Goudercourt, Denise; Delcour, Jean; Turneer, Mireille; Mercenier, Annick

    2004-05-01

    The potential of recombinant lactic acid bacteria (LAB) to deliver heterologous antigens to the immune system and to induce protective immunity has been best demonstrated by using the C subunit of tetanus toxin (TTFC) as a model antigen. Two types of LAB carriers have mainly been used, Lactobacillus plantarum and Lactococcus lactis, which differ substantially in their abilities to resist passage through the stomach and to persist in the mouse gastrointestinal tract. Here we analyzed the effect of a deficiency in alanine racemase, an enzyme that participates in cell wall synthesis, in each of these bacterial carriers. Recombinant wild-type and mutant strains of L. plantarum NCIMB8826 and L. lactis MG1363 producing TTFC intracellularly were constructed and used in mouse immunization experiments. Remarkably, we observed that the two cell wall mutant strains were far more immunogenic than their wild-type counterparts when the intragastric route was used. However, intestinal TTFC-specific immunoglobulin A was induced only after immunization with the recombinant L. plantarum mutant strain. Moreover, the alanine racemase mutant of either LAB strain allowed induction of a much stronger serum TTFC-specific immune response after immunization via the vagina, which is a quite different ecosystem than the gastrointestinal tract. The design and use of these mutants thus resulted in a major improvement in the mucosal delivery of antigens exhibiting vaccine properties.

  7. Co-inoculation of arbusculr mycorrhizae and nitrogen fixing bacteria enhance alfalfa yield under saline conditions

    International Nuclear Information System (INIS)

    Zhu, R.; Tang, F.; Liu, F.; Chen, J.

    2016-01-01

    The study was to investigate the effects of combined inoculation of Glomus mosseae (arbusculr mycorrhizae fungi, AMF) and Sinorhizobium meliloti (nitrogen-fixing bacteria, i.e., an Rhizobium meliloti, RM) on yield, nutrient contents, nodulation and mycorrhizal colonization of different alfalfa cultivars under saline conditions. An experiment was conducted to test the efficacy of AMF and RM inoculation in development of salt tolerance in alfalfa cultivars (Zhaodong, Nongjing and Longmu) under different salinity levels (0, 60, 120 and 180 mM NaCl). We found that under non stress condition, double inoculation of alfalfa with rhizobium and AM increased the alfalfa yield, nodule weight and number, as well as shoot proline contents, the most when plants were double inoculated followed by AM and rhizobium inoculation, respectively. Whereas under salinity condition, double inoculation of alfalfa with rhizobium and AM increased alfalfa yield, mycorrhizal infection, nodule weight and number as well as increased in shoot proline content, the most followed by AM and rhizobium inoculation, respectively. The Results suggest that growth of alfalfa may be improved by combined inoculation of alfalfa with AM and rhizobium under salt and non-stress conditions. Alleviation of alfalfa growth under saline condition was perhaps due to an increase in mycorrhizal infection and nodule weight and number as well as an increased in shoot proline content by dual inoculation. (author)

  8. Natural exopolysaccharides enhance survival of lactic acid bacteria in frozen dairy desserts.

    Science.gov (United States)

    Hong, S H; Marshall, R T

    2001-06-01

    Viable lactic acid-producing bacteria in frozen dairy desserts can be a source of beta-galactosidase for persons who absorb lactose insufficiently. However, freezing kills many of the cells, causing loss of enzymatic activity. Cultures selected for high beta-galactosidase activities and high survival rates in the presence of bile were examined for survivability during freezing in reduced-fat ice cream. Encapsulated S. thermophilus strains survived better than their nonencapsulated mutants in reduced-fat ice cream after freezing and frozen storage at -29 degrees C for 16 d (28 vs. 19%). However, a small nonencapsulated strain of Lactobacillus delbrueckii sp. bulgaricus survived better than the large encapsulated strain in reduced-fat ice cream. Factors that improved survival of encapsulated S. thermophilus 1068 in ice cream were 1) harvest of cells in the late-log phase of growth at 37 degrees C rather than at 40, 42.5, or 45 degrees C; 2) overrun at 50% rather than 100%; and 3) storage at -17 degrees C rather than -23 or -29 degrees C. Survival of strain ST1068 was unaffected by 1) neutralization of acid during growth or 2) substitution of nitrogen for air in building overrun.

  9. Optimization of recombinant bacteria expressing dsRNA to enhance insecticidal activity against a lepidopteran insect, Spodoptera exigua.

    Directory of Open Access Journals (Sweden)

    Mohammad Vatanparast

    Full Text Available Double-stranded RNA (dsRNA has been applied to control insect pests due to its induction of RNA interference (RNAi of a specific target gene expression. However, developing dsRNA-based insecticidal agent has been a great challenge especially against lepidopteran insect pests due to variations in RNAi efficiency. The objective of this study was to screen genes of chymotrypsins (SeCHYs essential for the survival of the beet armyworm, Spodoptera exigua, to construct insecticidal dsRNA. In addition, an optimal oral delivery method was developed using recombinant bacteria. At least 7 SeCHY genes were predicted from S. exigua transcriptomes. Subsequent analyses indicated that SeCHY2 was widely expressed in different developmental stages and larval tissues by RT-PCR and its expression knockdown by RNAi caused high mortality along with immunosuppression. However, a large amount of dsRNA was required to efficiently kill late instars of S. exigua because of high RNase activity in their midgut lumen. To minimize dsRNA degradation, bacterial expression and formulation of dsRNA were performed in HT115 Escherichia coli using L4440 expression vector. dsRNA (300 bp specific to SeCHY2 overexpressed in E. coli was toxic to S. exigua larvae after oral administration. To enhance dsRNA release from E. coli, bacterial cells were sonicated before oral administration. RNAi efficiency of sonicated bacteria was significantly increased, causing higher larval mortality at oral administration. Moreover, targeting young larvae possessing weak RNase activity in the midgut lumen significantly enhanced RNAi efficiency and subsequent insecticidal activity against S. exigua.

  10. Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers.

    Science.gov (United States)

    Lin, Tzu-Yu; Wei, Chia-Cheng; Huang, Chi-Wei; Chang, Chun-Han; Hsu, Fu-Lan; Liao, Vivian Hsiu-Chuan

    2016-03-23

    Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater.

  11. Ancient horizontal gene transfer from bacteria enhances biosynthetic capabilities of fungi.

    Directory of Open Access Journals (Sweden)

    Imke Schmitt

    Full Text Available Polyketides are natural products with a wide range of biological functions and pharmaceutical applications. Discovery and utilization of polyketides can be facilitated by understanding the evolutionary processes that gave rise to the biosynthetic machinery and the natural product potential of extant organisms. Gene duplication and subfunctionalization, as well as horizontal gene transfer are proposed mechanisms in the evolution of biosynthetic gene clusters. To explain the amount of homology in some polyketide synthases in unrelated organisms such as bacteria and fungi, interkingdom horizontal gene transfer has been evoked as the most likely evolutionary scenario. However, the origin of the genes and the direction of the transfer remained elusive.We used comparative phylogenetics to infer the ancestor of a group of polyketide synthase genes involved in antibiotic and mycotoxin production. We aligned keto synthase domain sequences of all available fungal 6-methylsalicylic acid (6-MSA-type PKSs and their closest bacterial relatives. To assess the role of symbiotic fungi in the evolution of this gene we generated 24 6-MSA synthase sequence tags from lichen-forming fungi. Our results support an ancient horizontal gene transfer event from an actinobacterial source into ascomycete fungi, followed by gene duplication.Given that actinobacteria are unrivaled producers of biologically active compounds, such as antibiotics, it appears particularly promising to study biosynthetic genes of actinobacterial origin in fungi. The large number of 6-MSA-type PKS sequences found in lichen-forming fungi leads us hypothesize that the evolution of typical lichen compounds, such as orsellinic acid derivatives, was facilitated by the gain of this bacterial polyketide synthase.

  12. Dietary exposure to benzoxazinoids enhances bacteria-induced monokine responses by peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Damgaard, Dres; Jensen, Bettina Margrethe; Palarasah, Yaseelan

    2015-01-01

    -out, the groups switched diets. Peripheral blood mononuclear cells (PBMCs) were stimulated with Porphyromonas gingivalis, Escherichia coli lipopolysaccharide (LPS), or tetanus toxoid (TT). PBMCs from a healthy donor received the same stimuli in presence of serum from each participant receiving BXs. The production...... of monokines, T-cell cytokines and T-helper cell proliferation were assessed. A 3-wk diet with high BX content enhanced IL-1β responses against LPS and P. gingivalis, as well as TNF-α response against P. gingivalis, after 24 h of stimulation. Moreover, IL-6 was found to be increased after 7 days of stimulation...

  13. Enhanced dissolution of TCE in NAPL by TCE-degrading bacteria in wetland soils

    International Nuclear Information System (INIS)

    Lee, Sangjin

    2007-01-01

    The influence of trichloroethene (TCE) dechlorinating mixed cultures in dissolution of TCE in nonaqueous phase liquid (NAPL) via biodegradation was observed. Experiments were conducted in batch reactor system with and without marsh soils under 10 and 20 deg. C for 2 months. The dissolution phenomenon in biotic reactors containing mixed cultures was showed temporal increases compared to abiotic reactors treated with biocide. Effective NAPL-water transfer rate (K m ) calculated in this study showed more than four times higher in biotic reactors than that in abiotic reactors. The results might be attributed to the biologically enhanced dissolution process via dechlorination in reactors. Temperature would be a factor to determine the dissolution rate by controlling bacterial activity. The TCE dechlorination occurred even in an interface of TCE-NAPL that demonstrated no previous TCE biodegradation, suggesting that microbes may be useful in developing source-zone bioremediation system. In conclusion, dechlorinating mixed culture could enhance dissolution in NAPL that may be useful in the application of source zone bioremediation

  14. Bio-immobilization of dark fermentative bacteria for enhancing continuous hydrogen production from cornstalk hydrolysate.

    Science.gov (United States)

    Zhao, Lei; Cao, Guang-Li; Sheng, Tao; Ren, Hong-Yu; Wang, Ai-Jie; Zhang, Jian; Zhong, Ying-Juan; Ren, Nan-Qi

    2017-11-01

    Mycelia pellets were employed as biological carrier in a continuous stirred tank reactor to reduce biomass washout and enhance hydrogen production from cornstalk hydrolysate. Hydraulic retention time (HRT) and influent substrate concentration played critical roles on hydrogen production of the bioreactor. The maximum hydrogen production rate of 14.2mmol H 2 L -1 h -1 was obtained at optimized HRT of 6h and influent concentration of 20g/L, 2.6 times higher than the counterpart without mycelia pellets. With excellent immobilization ability, biomass accumulated in the reactor and reached 1.6g/L under the optimum conditions. Upon further energy conversion analysis, continuous hydrogen production with mycelia pellets gave the maximum energy conversion efficiency of 17.8%. These results indicate mycelia pellet is an ideal biological carrier to improve biomass retention capacity of the reactor and enhance hydrogen recovery efficiency from lignocellulosic biomass, and meanwhile provides a new direction for economic and efficient hydrogen production process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Surfactant-Enhanced Size-Excluded Transport of Bacteria Through Unsaturated Porous Media.

    Science.gov (United States)

    Zhu, J.

    2017-12-01

    US domestic waste water is rich in surfactants because of the intensive usage of surfactants-containing household product. It results in a surfactants presence environment when this untreated waste water released into subsurface. It was reported that surfactants enhance the colloidal transport in porous media, which have significant effect on issues such as subsurface pathogens contamination and biodegradation. In this study, soil column experiments were conducted. The soil column was remained unsaturated and with a steady flow passing through it. Escherichia coli K-12 transported in the soil column and its breakthrough data was collected in presence of surfactant anionic surfactant linear alkylbenzene sulfonate (LAS) concentration range over 0, 0.25, 0.5, 0.75, 1, and 2 times Critical Micelle Concentration (CMC). It was found that the increase in LAS concentration greatly increases breakthrough concentration C/C0 and decreases breakthrough time tb until LAS concentration reaches 1 xCMC. Numerical models were built simulating and investigating this phenomenon. The goodness of model fitting was greatly improved by adding exclusion factor into the model, which indicated that the presence of surfactant might enhance the exclusion effect. The relationships between LAS concentration and the two coefficients, deposition rate coefficient k and exclusion effect coefficient θim, were found can be fitted by a quasi-Langmuir equation. And the model validation with observed data showed that the model has an acceptable reliability.

  16. Bacteria within the gastrointestinal tract microbiota correlated with improved growth and feed conversion: Challenges presented for the identification of performance enhancing probiotic bacteria

    Directory of Open Access Journals (Sweden)

    Dragana eStanley

    2016-02-01

    Full Text Available Identification of bacteria associated with desirable productivity outcomes in animals may offer a direct approach to the identification of probiotic bacteria for use in animal production. We performed three controlled chicken trials (n=96 to investigate caecal microbiota differences between the best and poorest performing birds using four performance measures; Feed Conversion Rate (FCR, utilisation of energy from the feed measured as Apparent Metabolisable Energy (AME, gain rate (GR and amount of feed eaten (FE. The shifts in microbiota composition associated with the performance measures were very different between the three trials. Analysis of the caecal microbiota revealed that the high and low FCR birds had significant differences in the abundance of some bacteria as demonstrated by shifts in microbiota alpha and beta diversity. Trials 1 and 2 showed significant overall community shifts, however the microbial changes driving the difference between good and poor performers were very different. Lachnospiraceae, Ruminococcaceae and Erysipelotrichaceae families and genera Ruminococcus, Faecalibacterium and multiple lineages of genus Clostridium (from families Lachnospiraceae, Ruminococcaceae and Erysipelotrichaceae were highly abundant in good FCR birds in Trial 1. Different microbiota was associated with FCR in Trial 2; Catabacteriaceae and unknown Clostridiales family members were increased in good FCR and genera Clostridium (from family Clostridiaceae and Lactobacillus were associated with poor FCR. Trial 3 had only mild microbiota differences associated with all 4 performance measures. Overall, the genus Lactobacillus was correlated with feed intake which resulted in poor FCR performance. The genus Faecalibacterium correlated with improved FCR, increased GR and reduced FE. There was overlap in phylotypes correlated with improved FCR and GR, while different microbial cohorts appeared to be correlated with FE. Even under controlled conditions

  17. Thermally enhanced bioremediation of a gasoline-contaminated aquifer using toluene oxidizing bacteria

    International Nuclear Information System (INIS)

    Deeb, R.; Alvarez-Cohen, L.

    1994-01-01

    The combined application of steam injection and vacuum extraction has proved to be very effective for the in situ remediation of a gasoline contaminated aquifer. It is expected that the steam treated zone with its near-sterile nature, increased temperature, and decreased level of contaminant concentration will provide a superior environment for enhanced bioremediation, and will favor the survival of an introduced microbial culture for the destruction of residual gasoline hydrocarbons and especially BTEX compounds (Benzene, Toluene, Ethyl benzene, and Xylene). A mixed microbial culture seeded from the pre-steamed aquifer material was enriched in a laboratory chemostat on toluene, a major gasoline aromatic. Studies were conducted to determine the optimal conditions for microbial growth and activity. Growth rate studies conducted at different temperatures revealed that cell growth was optimal at 35 C, a temperature at which the aquifer can be maintained using the existing steam injection wells. The enriched culture was shown to degrade all BTEX compounds successfully both individually and in mixtures. Substrate toxicity was observed for some of the gasoline aromatics but at concentration levels well above those found in groundwater. When cells were exposed to mixtures of BTEX compounds, the biodegradation of xylene, the most recalcitrant aromatic among BTEX compounds, was stimulated. When cells were exposed to gasoline, BTEX degradation proceeded with no apparent inhibition by gasoline aliphatics; little aliphatic degradation took place, however, suggesting the absence of monooxygenase enzymes in the mixed culture. In mixtures of both toluene and propane enriched cultures, only dioxygenase activity was observed

  18. Identification of bacteria used for microbial enhanced oil recovery process by fluorescence in situ hybridization technique

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, K.; Tanaka, S.; Otsuka, M. [Kansai Research Institute, Kyoto (Japan). Lifescience Lab.; Yonebayashi, H. [Japan National Oil Corp., Chiba (Japan). Tech. Research Center; Enomoto, H. [Tohoku University, Sendai (Japan). Dept. of Geoscience and Tech.

    2000-01-01

    A fluorescence in situ hybridization (FISH) technique using 16S rRNA-targeted oligonucleotide probes was developed for rapid detection of microorganisms for use in the microbial enhancement of oil recovery (MEOR) process. Two microorganisms, Enterobacter cloacae TRC-322 and Bacillus licheniformis TRC-18-2-a, were selected from a collection of Enterobacter sp. and Bacillus sp. which were screened in previous studies as candidate microorganisms for injection, and were used for this experiment. Oligonucleotide probes, design based on specific sequences in the 16S rRNA gene were labeled with either fluorescein isothiocyanate (FITC), or 6-car-boxy-X-rhodamine (ROX), and were allowed to hybridize with fixed cells of the two microorganisms noted above. The fluorescence signal emitted from each microorganism cells could clearly be detected by an epifluorescence microscope. Moreover, E. cloacae TRC-322 and B, licheniformis TRC-18-2-a, suspended in actual reservoir brine, including inorganic salts, oil and aboriginal cells of the reservoir brine, could be detected directly by this hybridization method, without the need for cultivation and isolation. (author)

  19. A structural framework for a near-minimal form of life: mass and compositional analysis of the helical mollicute Spiroplasma melliferum BC3.

    Directory of Open Access Journals (Sweden)

    Shlomo Trachtenberg

    Full Text Available Spiroplasma melliferum is a wall-less bacterium with dynamic helical geometry. This organism is geometrically well defined and internally well ordered, and has an exceedingly small genome. Individual cells are chemotactic, polar, and swim actively. Their dynamic helicity can be traced at the molecular level to a highly ordered linear motor (composed essentially of the proteins fib and MreB that is positioned on a defined helical line along the internal face of the cell's membrane. Using an array of complementary, informationally overlapping approaches, we have taken advantage of this uniquely simple, near-minimal life-form and its helical geometry to analyze the copy numbers of Spiroplasma's essential parts, as well as to elucidate how these components are spatially organized to subserve the whole living cell. Scanning transmission electron microscopy (STEM was used to measure the mass-per-length and mass-per-area of whole cells, membrane fractions, intact cytoskeletons and cytoskeletal components. These local data were fit into whole-cell geometric parameters determined by a variety of light microscopy modalities. Hydrodynamic data obtained by analytical ultracentrifugation allowed computation of the hydration state of whole living cells, for which the relative amounts of protein, lipid, carbohydrate, DNA, and RNA were also estimated analytically. Finally, ribosome and RNA content, genome size and gene expression were also estimated (using stereology, spectroscopy and 2D-gel analysis, respectively. Taken together, the results provide a general framework for a minimal inventory and arrangement of the major cellular components needed to support life.

  20. Soil bacteria showing a potential of chlorpyrifos degradation and plant growth enhancement

    Directory of Open Access Journals (Sweden)

    Shamsa Akbar

    Full Text Available ABSTRACT Background: Since 1960s, the organophosphate pesticide chlorpyrifos has been widely used for the purpose of pest control. However, given its persistence and toxicity towards life forms, the elimination of chlorpyrifos from contaminated sites has become an urgent issue. For this process bioremediation is the method of choice. Results: Two bacterial strains, JCp4 and FCp1, exhibiting chlorpyrifos-degradation potential were isolated from pesticide contaminated agricultural fields. These isolates were able to degrade 84.4% and 78.6% of the initial concentration of chlorpyrifos (100 mg L-1 within a period of only 10 days. Based on 16S rRNA sequence analysis, these strains were identified as Achromobacter xylosoxidans (JCp4 and Ochrobactrum sp. (FCp1. These strains exhibited the ability to degrade chlorpyrifos in sterilized as well as non-sterilized soils, and were able to degrade 93-100% of the input concentration (200 mg kg-1 within 42 days. The rate of degradation in inoculated soils ranged from 4.40 to 4.76 mg-1 kg-1 d-1 with rate constants varying between 0.047 and 0.069 d-1. These strains also displayed substantial plant growth promoting traits such as phosphate solubilization, indole acetic acid production and ammonia production both in absence as well as in the presence of chlorpyrifos. However, presence of chlorpyrifos (100 and 200 mg L-1 was found to have a negative effect on indole acetic acid production and phosphate solubilization with percentage reduction values ranging between 2.65-10.6% and 4.5-17.6%, respectively. Plant growth experiment demonstrated that chlorpyrifos has a negative effect on plant growth and causes a decrease in parameters such as percentage germination, plant height and biomass. Inoculation of soil with chlorpyrifos-degrading strains was found to enhance plant growth significantly in terms of plant length and weight. Moreover, it was noted that these strains degraded chlorpyrifos at an increased rate (5

  1. Soil bacteria showing a potential of chlorpyrifos degradation and plant growth enhancement.

    Science.gov (United States)

    Akbar, Shamsa; Sultan, Sikander

    2016-01-01

    Since 1960s, the organophosphate pesticide chlorpyrifos has been widely used for the purpose of pest control. However, given its persistence and toxicity towards life forms, the elimination of chlorpyrifos from contaminated sites has become an urgent issue. For this process bioremediation is the method of choice. Two bacterial strains, JCp4 and FCp1, exhibiting chlorpyrifos-degradation potential were isolated from pesticide contaminated agricultural fields. These isolates were able to degrade 84.4% and 78.6% of the initial concentration of chlorpyrifos (100mgL(-1)) within a period of only 10 days. Based on 16S rRNA sequence analysis, these strains were identified as Achromobacter xylosoxidans (JCp4) and Ochrobactrum sp. (FCp1). These strains exhibited the ability to degrade chlorpyrifos in sterilized as well as non-sterilized soils, and were able to degrade 93-100% of the input concentration (200mgkg(-1)) within 42 days. The rate of degradation in inoculated soils ranged from 4.40 to 4.76mg(-1)kg(-1)d(-1) with rate constants varying between 0.047 and 0.069d(-1). These strains also displayed substantial plant growth promoting traits such as phosphate solubilization, indole acetic acid production and ammonia production both in absence as well as in the presence of chlorpyrifos. However, presence of chlorpyrifos (100 and 200mgL(-1)) was found to have a negative effect on indole acetic acid production and phosphate solubilization with percentage reduction values ranging between 2.65-10.6% and 4.5-17.6%, respectively. Plant growth experiment demonstrated that chlorpyrifos has a negative effect on plant growth and causes a decrease in parameters such as percentage germination, plant height and biomass. Inoculation of soil with chlorpyrifos-degrading strains was found to enhance plant growth significantly in terms of plant length and weight. Moreover, it was noted that these strains degraded chlorpyrifos at an increased rate (5.69mg(-1)kg(-1)d(-1)) in planted soil. The

  2. Enhancing plant productivity while suppressing biofilm growth in a windowfarm system using beneficial bacteria and ultraviolet irradiation.

    Science.gov (United States)

    Lee, Seungjun; Ge, Chongtao; Bohrerova, Zuzana; Grewal, Parwinder S; Lee, Jiyoung

    2015-07-01

    Common problems in a windowfarm system (a vertical and indoor hydroponic system) are phytopathogen infections in plants and excessive buildup of biofilms. The objectives of this study were (i) to promote plant health by making plants more resistant to infection by using beneficial biosurfactant-producing Pseudomonas chlororaphis around the roots and (ii) to minimize biofilm buildup by ultraviolet (UV) irradiation of the water reservoir, thereby extending the lifespan of the whole system with minimal maintenance. Pseudomonas chlororaphis-treated lettuce grew significantly better than nontreated lettuce, as indicated by enhancement of color, mass, length, and number of leaves per head (p < 0.05). The death rate of the lettuce was reduced by ∼ 50% when the lettuce was treated with P. chlororaphis. UV irradiation reduced the bacteria (4 log reduction) and algae (4 log reduction) in the water reservoirs and water tubing systems. Introduction of P. chlororaphis into the system promoted plant growth and reduced damage caused by the plant pathogen Pythium ultimum. UV irradiation of the water reservoir reduced algal and biofilm growth and extended the lifespan of the system.

  3. Combined bioaugmentation with anaerobic ruminal fungi and fermentative bacteria to enhance biogas production from wheat straw and mushroom spent straw.

    Science.gov (United States)

    Ferraro, Alberto; Dottorini, Giulia; Massini, Giulia; Mazzurco Miritana, Valentina; Signorini, Antonella; Lembo, Giuseppe; Fabbricino, Massimiliano

    2018-07-01

    Bioaugmentation with anaerobic ruminal fungi and a pool of hydrogen-producing fermenting bacteria was tested on wheat straw (WS) and mushroom spent straw (MSS) with the aim of improving anaerobic digestion performance. Batch tests were set up to simulate a Bioaugmentation Anaerobic Digestion (BAD) treatment comparing single- (I-BAD) and two-stage (II-BAD) process configurations, at two reactor scales, 120 and 1200 ml (×10). In both cases, higher CH 4 cumulative production was obtained in the II-BAD configuration on WS (65.1 ± 8.9 Nml and 922 ± 73.8 Nml respectively). The II-BADx10 tests allowed increasing CH 4 production (≃290% and ≃330% on WS and MSS, respectively) when compared to the unaugmented condition. Final results highlighted the achievable advantages of the two stage configuration in terms of CH 4 production enhancement. Microbial community investigations confirmed the efficiency of the bioaugmentation treatment and revealed that such a result was mainly related to the Methanosarcinales increase, mostly composed by Methanosaeta. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Mining Halophytes for Plant Growth-Promoting Halotolerant Bacteria to Enhance the Salinity Tolerance of Non-halophytic Crops

    Directory of Open Access Journals (Sweden)

    Hassan Etesami

    2018-02-01

    Full Text Available Salinity stress is one of the major abiotic stresses limiting crop production in arid and semi-arid regions. Interest is increasing in the application of PGPRs (plant growth promoting rhizobacteria to ameliorate stresses such as salinity stress in crop production. The identification of salt-tolerant, or halophilic, PGPRs has the potential to promote saline soil-based agriculture. Halophytes are a useful reservoir of halotolerant bacteria with plant growth-promoting capabilities. Here, we review recent studies on the use of halophilic PGPRs to stimulate plant growth and increase the tolerance of non-halophytic crops to salinity. These studies illustrate that halophilic PGPRs from the rhizosphere of halophytic species can be effective bio-inoculants for promoting the production of non-halophytic species in saline soils. These studies support the viability of bioinoculation with halophilic PGPRs as a strategy for the sustainable enhancement of non-halophytic crop growth. The potential of this strategy is discussed within the context of ensuring sustainable food production for a world with an increasing population and continuing climate change. We also explore future research needs for using halotolerant PGPRs under salinity stress.

  5. Effect of carbon sources on the aggregation of photo fermentative bacteria induced by L-cysteine for enhancing hydrogen production.

    Science.gov (United States)

    Xie, Guo-Jun; Liu, Bing-Feng; Ding, Jie; Wang, Qilin; Ma, Chao; Zhou, Xu; Ren, Nan-Qi

    2016-12-01

    Poor flocculation of photo fermentative bacteria resulting in continuous biomass washout from photobioreactor is a critical challenge to achieve rapid and stable hydrogen production. In this work, the aggregation of Rhodopseudomonas faecalis RLD-53 was successfully developed in a photobioreactor and the effects of different carbon sources on hydrogen production and aggregation ability were investigated. Extracellular polymeric substances (EPS) production by R. faecalis RLD-53 cultivated using different carbon sources were stimulated by addition of L-cysteine. The absolute ζ potentials of R. faecalis RLD-53 were considerably decreased with addition of L-cysteine, and aggregation barriers based on DLVO dropped to 15-43 % of that in control groups. Thus, R. faecalis RLD-53 flocculated effectively, and aggregation abilities of strain RLD-53 cultivated with acetate, propionate, lactate and malate reached 29.35, 32.34, 26.07 and 24.86 %, respectively. In the continuous test, hydrogen-producing activity was also promoted and reached 2.45 mol H 2 /mol lactate, 3.87 mol H 2 /mol propionate and 5.10 mol H 2 /mol malate, respectively. Therefore, the aggregation of R. faecalis RLD-53 induced by L-cysteine is independent on the substrate types, which ensures the wide application of this technology to enhance hydrogen recovery from wastewater dominated by different organic substrates.

  6. Production of biosurfactant from Bacillus licheniformis for microbial enhanced oil recovery and inhibition the growth of sulfate reducing bacteria

    Directory of Open Access Journals (Sweden)

    H.S. El-Sheshtawy

    2015-06-01

    Full Text Available In this study, the bacterium Bacillus licheniformis has been isolated from oil reservoir; the ability of this bacterium to produce a biosurfactant was detected. Surface properties of the produced biosurfactant were confirmed by determining the emulsification power as well as surface and interfacial tension. The crude biosurfactant has been extracted from supernatant culture growth, and the yield of crude biosurfactant was about 1 g/l. Also, chemical structure of the produced biosurfactant was confirmed using FTIR analysis. Results revealed that, the emulsification power has been increased up to 96% and the surface tension decreased from 72 of distilled water to 36 mN/m after 72 h of incubation. The potential application of this bacterial species in microbial-enhanced oil recovery (MEOR was investigated. The percent of oil recovery was 16.6% upon application in a sand pack column designed to stimulate an oil recovery. It also showed antimicrobial activity against the growth of different strains of SRB (sulfate reducing bacteria. Results revealed that a complete inhibition of SRB growth using 1.0% crude biosurfactant is achieved after 3 h.

  7. Epiphytic pink-pigmented methylotrophic bacteria enhance germination and seedling growth of wheat (Triticum aestivum) by producing phytohormone.

    Science.gov (United States)

    Meena, Kamlesh K; Kumar, Manish; Kalyuzhnaya, Marina G; Yandigeri, Mahesh S; Singh, Dhananjaya P; Saxena, Anil K; Arora, Dilip K

    2012-05-01

    Methylotrophic bacteria were isolated from the phyllosphere of different crop plants such as sugarcane, pigeonpea, mustard, potato and radish. The methylotrophic isolates were differentiated based on growth characteristics and colony morphology on methanol supplemented ammonium mineral salts medium. Amplification of the mxaF gene helped in the identification of the methylotrophic isolates as belonging to the genus Methylobacterium. Cell-free culture filtrates of these strains enhanced seed germination of wheat (Triticum aestivum) with highest values of 98.3% observed using Methylobacterium sp. (NC4). Highest values of seedling length and vigour were recorded with Methylobacterium sp. (NC28). HPLC analysis of production by bacterial strains ranged from 1.09 to 9.89 μg ml(-1) of cytokinins in the culture filtrate. Such cytokinin producing beneficial methylotrophs can be useful in developing bio-inoculants through co-inoculation of pink-pigmented facultative methylotrophs with other compatible bacterial strains, for improving plant growth and productivity, in an environment-friendly manner.

  8. Triterpenoid herbal saponins enhance beneficial bacteria, decrease sulfate-reducing bacteria, modulate inflammatory intestinal microenvironment and exert cancer preventive effects in ApcMin/+ mice

    Science.gov (United States)

    Chen, Lei; Brar, Manreetpal S.; Leung, Frederick C. C.; Hsiao, W. L. Wendy

    2016-01-01

    Saponins derived from medicinal plants have raised considerable interest for their preventive roles in various diseases. Here, we investigated the impacts of triterpenoid saponins isolated from Gynostemma pentaphyllum (GpS) on gut microbiome, mucosal environment, and the preventive effect on tumor growth. Six-week old ApcMin/+ mice and their wild-type littermates were fed either with vehicle or GpS daily for the duration of 8 weeks. The fecal microbiome was analyzed by enterobacterial repetitive intergenic consensus (ERIC)-PCR and 16S rRNA gene pyrosequencing. Study showed that GpS treatment significantly reduced the number of intestinal polyps in a preventive mode. More importantly, GpS feeding strikingly reduced the sulfate-reducing bacteria lineage, which are known to produce hydrogen sulfide and contribute to damage the intestinal epithelium or even promote cancer progression. Meanwhile, GpS also boosted the beneficial microbes. In the gut barrier of the ApcMin/+ mice, GpS treatment increased Paneth and goblet cells, up-regulated E-cadherin and down-regulated N-cadherin. In addition, GpS decreased the pro-oncogenic β-catenin, p-Src and the p-STAT3. Furthermore, GpS might also improve the inflamed gut epithelium of the ApcMin/+ mice by upregulating the anti-inflammatory cytokine IL-4, while downregulating pro-inflammatory cytokines TNF-β, IL-1β and IL-18. Intriguingly, GpS markedly stimulated M2 and suppressed M1 macrophage markers, indicating that GpS altered mucosal cytokine profile in favor of the M1 to M2 macrophages switching, facilitating intestinal tissue repair. In conclusion, GpS might reverse the host's inflammatory phenotype by increasing beneficial bacteria, decreasing sulfate-reducing bacteria, and alleviating intestinal inflammatory gut environment, which might contribute to its cancer preventive effects. PMID:27121311

  9. Enhanced performance of the microalga Chlorella sorokiniana remotely induced by the plant growth-promoting bacteria Azospirillum brasilense and Bacillus pumilus

    Science.gov (United States)

    Amavizca, Edgar; Bashan, Yoav; Ryu, Choong-Min; Farag, Mohamed A.; Bebout, Brad M.; de-Bashan, Luz E.

    2017-01-01

    Remote effects (occurring without physical contact) of two plant growth-promoting bacteria (PGPB) Azospirillum brasilense Cd and Bacilus pumilus ES4 on growth of the green microalga Chlorella sorokiniana UTEX 2714 were studied. The two PGPB remotely enhanced the growth of the microalga, up to six-fold, and its cell volume by about three-fold. In addition to phenotypic changes, both bacteria remotely induced increases in the amounts of total lipids, total carbohydrates, and chlorophyll a in the cells of the microalga, indicating an alteration of the microalga’s physiology. The two bacteria produced large amounts of volatile compounds, including CO2, and the known plant growth-promoting volatile 2,3-butanediol and acetoin. Several other volatiles having biological functions in other organisms, as well as numerous volatile compounds with undefined biological roles, were detected. Together, these bacteria-derived volatiles can positively affect growth and metabolic parameters in green microalgae without physical attachment of the bacteria to the microalgae. This is a new paradigm on how PGPB promote growth of microalgae which may serve to improve performance of Chlorella spp. for biotechnological applications. PMID:28145473

  10. Anaerobic bacteria

    Science.gov (United States)

    Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Brook I. Diseases caused by non-spore-forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

  11. Adaptation of Bacteria of Anaerobic Digestion to Higher Salinity for the Application to Microbial Enhanced Oil Recovery

    DEFF Research Database (Denmark)

    Rudyk, Svetlana Nikolayevna; Ivanova, Yanina; Spirov, Pavel

    g/L in the volume of 350 g/L. To revitalize bacteria and activate gas production, 200 mL salty water and 5 mL molasses were added. On the 6th day of the experiment, the maximum production was 1300 mL at 90 g/L and the minimum of 400 mL at 80 g/L. The experiment showed that bacteria of anaerobic......For this study, bacteria of anaerobic digestion from Ribe Biogas plant, Denmark, were chosen. The volume of the produced gas from the bacteria was measured in a water displacement setup every day. After the gas production ceased in the second day, the maximum produced gas was measured at 70 and 90...

  12. The ability of selected plant essential oils to enhance the action of recommended antibiotics against pathogenic wound bacteria.

    Science.gov (United States)

    Sienkiewicz, Monika; Łysakowska, Monika; Kowalczyk, Edward; Szymańska, Grażyna; Kochan, Ewa; Krukowska, Jolanta; Olszewski, Jurek; Zielińska-Bliźniewska, Hanna

    2017-03-01

    The aim of this work was to characterize the ability of essential oils to support antibiotics against pathogenic bacteria in wounds. Gram-positive and Gram-negative bacteria obtained from wound infections were identified according to standard microbiological methods. Essential oils were analysed by GC-FID-MS. The susceptibility of bacteria to antibiotics, essential oils and their combination was assessed using the disc-diffusion method. The Minimal Inhibitory Concentration and Minimum Bactericidal Concentration of the essential oils were established by the micro-dilution broth method. Although cinnamon, clove, thyme and lavender essential oils were found to have the greatest antibacterial activity when used alone, the greatest additive and synergistic effects against pathogenic wound bacteria in combination with recommended antibiotics were demonstrated by basil, clary sage and rosemary oils. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

  13. Selectively enhanced expression of prophenoloxidase activating enzyme 1 (PPAE1 at a bacteria clearance site in the white shrimp, Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Jang In-Kwon

    2011-12-01

    Full Text Available Abstract Background The prophenoloxidase-activating (PO activating system plays an important role in the crustacean innate immunity, particularly in wound healing and pathogen defense. A key member of this system is prophenoloxidase-activating enzyme (PPAE, which is the direct activator of prophenoloxidase (proPO. Despite their importance in crustacean PO activating system, the studies on them remain limited. Results Here we report on a PPAE of white shrimp, Litopenaeus vannamei (lvPPAE1, which showed 94% similarity to PPAE1 of Penaeus monodon. We found that lvPPAE1 in fluid hemocytes was down regulated after challenge by Vibrio harveyi but was enhanced when shrimps were exposed to a bacteria-rich environment for long-term. In vivo gene silence of lvPPAE1 by RNAi can significantly reduce the phenoloxidase activity (PO and increase the susceptibility of shrimps to V. harveyi. Although lvPPAE1 was down-regulated in fluid hemocytes by Vibrio challenge, its expression increased significantly in gill after bacteria injection, which is the primary bacteria-clearance tissue. Conclusion Suppressed expression in fluid hemocytes and enhanced expression in gill indicates selectively enhanced expression at the bacterial clearance site. This is a novel feature for PPAE expression. The results will contribute to our understanding of the PO activating system in crustaceans.

  14. Enhancing effects of picocyanobacteria on growth and hydrocarbon consumption potential of the associated oil-utilizing bacteria

    International Nuclear Information System (INIS)

    Radwan, S.S.; Al-Hasan, R.H.; Salamah, S.

    2004-01-01

    Marine surface waters around the world are rich in unicellular cyanobacteria or picocyanobacteria. This paper presents the results of a study which focused on the interaction of microorganisms in naturally occurring marine consortium active in hydrocarbon attenuation. Picocyanobacteria are minute phototrophs which accumulate hydrocarbons from water without any potential for oxidizing these compounds. This study demonstrates that the picocyanobacteria are part of a microbial consortia floating on the water surface of the Arabian Gulf. The consortia are include a rich population of oil-utilizing true bacteria whose growth and activities are improved in the presence of cyanobacterial partners. Each gram of picocyanobacterial biomass was associated with 10 8 - 10 12 cells of oil-utilizing bacteria. Studies have shown that oil-utilizing bacteria grow better in the presence of their partner picocyanobacteria. In addition, the oil-utilizing bacteria resulted in more powerful hydrocarbon attenuation in the presence of picocyanobacteria. Picocyanobacterial cells accumulate hydrocarbon from water without biodegrading it. The oil-utilizing bacteria grew on hydrocarbons for a source of carbon and energy. It was concluded that the oil-polluted environment of the Arabian Gulf can be cleaned effectively by the cooperative activities of this oil consuming group of bacteria composed of symbiotic microorganisms floating in the Gulf waters. 17 refs., 1 tab., 6 figs

  15. Enhancement in ex vivo phagocytic capacity of peritoneal leukocytes in mice by oral delivery of various lactic-acid-producing bacteria.

    Science.gov (United States)

    Lee, Yeonhee; Lee, Taik-Soo

    2005-01-01

    Lactic-acid-producing bacteria (LABs) are known to have immunomodulating activity. In the current study, various LABs were tested for their immunity-enhancing activity, especially the phagocytic activity of leukocytes. Viable but not heat-killed cells of Weissella kimchii strain PL9001, Lactobacillus fermentum strain PL9005, and L. plantarum strain PL9011 significantly increased the ex vivo phagocytic capacity of mouse peritoneal leukocytes to ingest fluorescein isothiocyanate (FITC)-labeled Escherichia coli in a strain-dependent manner. Results of this and previous studies suggest these LABs as candidates for new probiotics. This is the first report of the enhancement of peritoneal leukocyte activity of these species.

  16. Cr-resistant rhizo- and endophytic bacteria associated with Prosopis juliflora and their potential as phytoremediation enhancing agents in metal-degraded soils

    Directory of Open Access Journals (Sweden)

    Muhammad Umar Khan

    2015-01-01

    Full Text Available Prosopis juliflora is characterized by distinct and profuse growth even in nutritionally poor soil and environmentally stressed conditions and is believed to harbor some novel heavy metal-resistant bacteria in the rhizosphere and endosphere. This study was performed to isolate and characterize Cr-resistant bacteria from the rhizosphere and endosphere of P. juliflora growing on the tannery effluent contaminated soil. A total of 5 and 21 bacterial strains were isolated from the rhizosphere and endosphere, respectively, could tolerate Cr up to 3000 mg l-1. These isolates also exhibited tolerance to other toxic heavy metals such as, Cd, Cu, Pb and Zn, and high concentration (174 g l-1 of NaCl. Moreover, most of the isolated bacterial strains showed one or more plant growth-promoting activities. The phylogenetic analysis of the 16S rRNA gene indicated a higher and wider range of population of Cr-resistant bacteria in the endosphere than rhizosphere and the predominant species included Bacillus, Staphylococcus and Aerococcus. As far as we know, this is the first report detecting rhizo- and endophytic bacterial population associated with P. juliflora growing on the tannery effluent contaminated soil. The inoculation of three isolates to ryegrass (Lolium multiflorum L. improved plant growth and heavy metal removal from the tannery effluent contaminated soil suggesting that these bacteria could enhance the establishment of the plant in contaminated soil and also improve the efficiency of phytoremediation of heavy metal-degraded soils.

  17. Experimental design for assessment of electrokinetically enhanced delivery of lactate and bacteria in 1,2-cis-dichloroethylene contaminated limestone

    DEFF Research Database (Denmark)

    Hyldegaard, Bente Højlund; Nedergaard, L. W.; Ottosen, Lisbeth

    2015-01-01

    Bacterial dechlorination of chlorinated solvents often causes accumulation of the intermediate cis-DCE. Back diffusion of e.g. cis-DCE, due to the dual porosity of limestone, often limits the remediation efficiency. A remediation scheme capable of establishing contact between contaminant, degrading...... bacteria and electron donor within the low permeable limestone matrix is required. The technology EK-BIO, which combines enhanced reductive dechlorination and electrokinetics (EK), was assessed. This novel technology has not previously been tested in limestone. An experimental set-up was designed to meet...... that fermentative bacteria were distributed by electrophoresis. This study suggests that EK application can establish the essential contact and overcome back diffusion. Thereby, EK-BIO may be superior to advection-based technologies for bioremediation of chlorinated solvent contaminated limestone matrices....

  18. A veritable menagerie of heritable bacteria from ants, butterflies, and beyond: broad molecular surveys and a systematic review.

    Directory of Open Access Journals (Sweden)

    Jacob A Russell

    Full Text Available Maternally transmitted bacteria have been important players in the evolution of insects and other arthropods, affecting their nutrition, defense, development, and reproduction. Wolbachia are the best studied among these and typically the most prevalent. While several other bacteria have independently evolved a heritable lifestyle, less is known about their host ranges. Moreover, most groups of insects have not had their heritable microflora systematically surveyed across a broad range of their taxonomic diversity. To help remedy these shortcomings we used diagnostic PCR to screen for five groups of heritable symbionts-Arsenophonus spp., Cardinium hertigii, Hamiltonella defensa, Spiroplasma spp., and Wolbachia spp.-across the ants and lepidopterans (focusing, in the latter case, on two butterfly families-the Lycaenidae and Nymphalidae. We did not detect Cardinium or Hamiltonella in any host. Wolbachia were the most widespread, while Spiroplasma (ants and lepidopterans and Arsenophonus (ants only were present at low levels. Co-infections with different Wolbachia strains appeared especially common in ants and less so in lepidopterans. While no additional facultative heritable symbionts were found among ants using universal bacterial primers, microbes related to heritable enteric bacteria were detected in several hosts. In summary, our findings show that Wolbachia are the dominant heritable symbionts of ants and at least some lepidopterans. However, a systematic review of symbiont frequencies across host taxa revealed that this is not always the case across other arthropods. Furthermore, comparisons of symbiont frequencies revealed that the prevalence of Wolbachia and other heritable symbionts varies substantially across lower-level arthropod taxa. We discuss the correlates, potential causes, and implications of these patterns, providing hypotheses on host attributes that may shape the distributions of these influential bacteria.

  19. Nanowire arrays as cell force sensors to investigate adhesin-enhanced holdfast of single cell bacteria and biofilm stability

    NARCIS (Netherlands)

    Sahoo, P.K.; Janissen, R.; Monteiro, M.P.; Cavalli, A.; Murillo, D.M.; Merfa, M.V.; Cesar, C.L.; Carvalho, H.F.; de Souza, A.A.; Bakkers, E.P.A.M.; Cotta, M.A.

    2016-01-01

    Surface attachment of a planktonic bacteria, mediated by adhesins and extracellular polymeric substances (EPS), is a crucial step for biofilm formation. Some pathogens can modulate cell adhesiveness, impacting host colonization and virulence. A framework able to quantify cell-surface interaction

  20. A novel surface-enhanced Raman scattering (SERS) detection for natural gas exploration using methane-oxidizing bacteria.

    Science.gov (United States)

    Liang, Weiwei; Chen, Qiao; Peng, Fang; Shen, Aiguo; Hu, Jiming

    2018-07-01

    Methane-oxidizing bacteria (MOB), a unique group of Gram-negative bacteria utilizing methane as a sole source of carbon and energy, have been proved to be a biological indicator for gas prospecting. Field and cultivation-free detection of MOB is important but still challenging in current microbial prospecting of oil and gas (MPOG) system. Herein, SERS was used for the first time to our knowledge to investigate two species of methanotrophs and four closely relevant bacteria that universally coexisted in the upper soil of natural gas. A special but very simple approach was utilized to make silver nanoparticles (Ag NPs) sufficiently contact with every single bacterial cell, and highly strong and distinct Raman signals free from any native fluorescence have been obtained, and successfully utilized for distinguishing MOB from other species. A more convincing multi-Raman criterion based on single Raman bands, and further the entire Raman spectrum in combination with statistical analysis (e.g., principal component analysis (PCA)), which were found capable of classifying MOB related bacterial cells in soil with an accuracy of 100%. This study therefore demonstrated sensitive and rapid SERS measurement technique accompanied by complete Raman database of various gas reservoirs related bacteria could aid field exploration of natural gas reservoir. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Interspecies interactions result in enhanced biofilm formation by co-cultures of bacteria isolated from a food processing environment

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng; Raghupathi, Prem Krishnan; Herschend, Jakob

    2015-01-01

    Bacterial attachment and biofilm formation can lead to poor hygienic conditions in food processing environments. Furthermore, interactions between different bacteria may induce or promote biofilm formation. In this study, we isolated and identified a total of 687 bacterial strains from seven......-culture biofilm production with high relevance for food safety and food production facilities....

  2. Exploitation of grape marc as functional substrate for lactic acid bacteria and bifidobacteria growth and enhanced antioxidant activity.

    Science.gov (United States)

    Campanella, Daniela; Rizzello, Carlo Giuseppe; Fasciano, Cristina; Gambacorta, Giuseppe; Pinto, Daniela; Marzani, Barbara; Scarano, Nicola; De Angelis, Maria; Gobbetti, Marco

    2017-08-01

    This study aimed at using grape marc for the growth of lactic acid bacteria and bifidobacteria with the perspective of producing a functional ingredient having antioxidant activity. Lactobacillus plantarum 12A and PU1, Lactobacillus paracasei 14A, and Bifidobacterium breve 15A showed the ability to grow on grape marc (GM) based media. The highest bacterial cell density (>9.0 CFU/g) was found in GM added of 1% of glucose (GMG). Compared to un-inoculated and incubated control fermented GMG showed a decrease of carbohydrates and citric acid together with an increase of lactic acid. The content of several free amino acids and phenol compounds differed between samples. Based on the survival under simulated gastro-intestinal conditions, GMG was a suitable carrier of lactic acid bacteria and bifidobacteria strains. Compared to the control, cell-free supernatant (CFS) of fermented GMG exhibited a marked antioxidant activity in vitro. The increased antioxidant activity was confirmed using Caco-2 cell line after inducing oxidative stress, and determining cell viability and radical scavenging activity through MTT and DCFH-DA assays, respectively. Supporting these founding, the SOD-2 gene expression of Caco-2 cells also showed a lowest pro-oxidant effect induced by the four CFS of GMG fermented by lactic acid bacteria and bifidobacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Alteration of Rumen Bacteria and Protozoa Through Grazing Regime as a Tool to Enhance the Bioactive Fatty Acid Content of Bovine Milk.

    Science.gov (United States)

    Bainbridge, Melissa L; Saldinger, Laurel K; Barlow, John W; Alvez, Juan P; Roman, Joe; Kraft, Jana

    2018-01-01

    Rumen microorganisms are the origin of many bioactive fatty acids (FA) found in ruminant-derived food products. Differences in plant leaf anatomy and chemical composition between cool- and warm-season pastures may alter rumen microorganisms, potentially enhancing the quantity/profile of bioactive FA available for incorporation into milk. The objective of this study was to identify rumen bacteria and protozoa and their cellular FA when cows grazed a warm-season annual, pearl millet (PM), in comparison to a diverse cool-season pasture (CSP). Individual rumen digesta samples were obtained from five Holstein cows in a repeated measures design with 28-day periods. The treatment sequence was PM, CSP, then PM. Microbial DNA was extracted from rumen digesta and sequence reads were produced with Illumina MiSeq. Fatty acids (FA) were identified in rumen bacteria and protozoa using gas-liquid chromatography/mass spectroscopy. Microbial communities shifted in response to grazing regime. Bacteria of the phylum Bacteroidetes were more abundant during PM than CSP ( P rumenic acid, and α-linolenic acid in milk. In conclusion, grazing regime can potentially be used to alter microbial communities shifting the FA profile of microbial cells, and subsequently, alter the milk FA profile.

  4. Enhanced biotic and abiotic transformation of Cr(vi) by quinone-reducing bacteria/dissolved organic matter/Fe(iii) in anaerobic environment.

    Science.gov (United States)

    Huang, Bin; Gu, Lipeng; He, Huan; Xu, Zhixiang; Pan, Xuejun

    2016-09-14

    This study investigated the simultaneous transformation of Cr(vi) via a closely coupled biotic and abiotic pathway in an anaerobic system of quinone-reducing bacteria/dissolved organic matters (DOM)/Fe(iii). Batch studies were conducted with quinone-reducing bacteria to assess the influences of sodium formate (NaFc), electron shuttling compounds (DOM) and the Fe(iii) on Cr(vi) reduction rates as these chemical species are likely to be present in the environment during in situ bioremediation. Results indicated that the concentration of sodium formate and anthraquinone-2-sodium sulfonate (AQS) had apparently an effect on Cr(vi) reduction. The fastest decrease in rate for incubation supplemented with 5 mM sodium formate and 0.8 mM AQS showed that Fe(iii)/DOM significantly promoted the reduction of Cr(vi). Presumably due to the presence of more easily utilizable sodium formate, DOM and Fe(iii) have indirect Cr(vi) reduction capability. The coexisting cycles of Fe(ii)/Fe(iii) and DOM(ox)/DOM(red) exhibited a higher redox function than the individual cycle, and their abiotic coupling action can significantly enhance Cr(vi) reduction by quinone-reducing bacteria.

  5. Enhanced degradation of chlorpyrifos in rice (Oryza sativa L.) by five strains of endophytic bacteria and their plant growth promotional ability.

    Science.gov (United States)

    Feng, Fayun; Ge, Jing; Li, Yisong; He, Shuang; Zhong, Jianfeng; Liu, Xianjing; Yu, Xiangyang

    2017-10-01

    Endophytic bacteria reside in plant tissues, such as roots, stems, leaves and seeds. Most of them can stimulate plant growth or alleviate phytotoxicity of pollutants. There are handful species with dual functions stimulating plant growth and degrading pollutants have been reported. Five endophytic bacteria were isolated from chlorpyrifos (CP) treated rice plants and identified as Pseudomonas aeruginosa strain RRA, Bacillus megaterium strain RRB, Sphingobacterium siyangensis strain RSA, Stenotrophomonas pavanii strain RSB and Curtobacterium plantarum strain RSC according to morphological characteristics, physiological and biochemical tests, and 16S rDNA phylogeny. All of them possessed some plant growth promotional traits, including indole acetic acid and siderophore production, secretion of phosphate solubilization and 1-aminocyclopropane-1-carboxylate deaminase. The bacteria were marked with the green fluorescent protein (gfp) gene and successfully colonized into rice plants. All isolates were able to degrade CP in vitro and in vivo. The five isolates degraded more than 90% of CP in 24 h when the initial concentration was lower than 5 mg/L. CP degradation was significantly enhanced in the infested rice plants and rice grains. The final CP residual was reduced up to 80% in the infested rice grains compared to the controls. The results indicate that these isolates are promising bio-inoculants for the removal or detoxification of CP residues in rice plants and grains. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Cr-resistant rhizo- and endophytic bacteria associated with Prosopis juliflora and their potential as phytoremediation enhancing agents in metal-degraded soils.

    Science.gov (United States)

    Khan, Muhammad U; Sessitsch, Angela; Harris, Muhammad; Fatima, Kaneez; Imran, Asma; Arslan, Muhammad; Shabir, Ghulam; Khan, Qaiser M; Afzal, Muhammad

    2014-01-01

    Prosopis juliflora is characterized by distinct and profuse growth even in nutritionally poor soil and environmentally stressed conditions and is believed to harbor some novel heavy metal-resistant bacteria in the rhizosphere and endosphere. This study was performed to isolate and characterize Cr-resistant bacteria from the rhizosphere and endosphere of P. juliflora growing on the tannery effluent contaminated soil. A total of 5 and 21 bacterial strains were isolated from the rhizosphere and endosphere, respectively, and were shown to tolerate Cr up to 3000 mg l(-1). These isolates also exhibited tolerance to other toxic heavy metals such as, Cd, Cu, Pb, and Zn, and high concentration (174 g l(-1)) of NaCl. Moreover, most of the isolated bacterial strains showed one or more plant growth-promoting activities. The phylogenetic analysis of the 16S rRNA gene showed that the predominant species included Bacillus, Staphylococcus and Aerococcus. As far as we know, this is the first report analyzing rhizo- and endophytic bacterial communities associated with P. juliflora growing on the tannery effluent contaminated soil. The inoculation of three isolates to ryegrass (Lolium multiflorum L.) improved plant growth and heavy metal removal from the tannery effluent contaminated soil suggesting that these bacteria could enhance the establishment of the plant in contaminated soil and also improve the efficiency of phytoremediation of heavy metal-degraded soils.

  7. Covalent assembly of poly(ethyleneimine) via layer-by-layer deposition for enhancing surface density of protein and bacteria attachment

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Bing, E-mail: xiabing@njfu.edu.cn [Key Laboratory of Forest Genetics and Biotechnology (Ministry of Education of China), Nanjing Forestry University, Nanjing 210037 (China); Advanced Analysis and Testing Center, Nanjing Forestry University, Nanjing 210037 (China); Shi, Jisen; Dong, Chen; Zhang, Wenyi; Lu, Ye [Key Laboratory of Forest Genetics and Biotechnology (Ministry of Education of China), Nanjing Forestry University, Nanjing 210037 (China); Guo, Ping [Nanjing College of Information Technology, Nanjing 210023 (China)

    2014-02-15

    Covalently assembly of low molecular weight poly(ethyleneimine) was introduced to glass surfaces via glutaraldehyde crosslinking, with focus on its application on protein immobilization or bacteria attachment. Characterizations of Fourier transform infrared spectroscopy and ellipsometry measurement revealed a stepwise growth of poly(ethyleneimine) films by layer-by-layer deposition. After fluorescein isothiocyanate labelling, photoluminescence spectroscopy measurement indicated that the amount of surface accessible amine groups had been gradually enhanced with increasing poly(ethyleneimine) layers deposition. As compared with traditional aminosilanized surfaces, the surface density of amine groups was enhanced by ∼11 times after five layers grafting, which resulted in ∼9-time increasing of surface density of immobilized bovine serum albumin. Finally, these as-prepared PEI multi-films with excellent biocompatibility were adopted as culture substrates to improve Escherichia coli adherence, which showed that their surface density had been increased by ∼251 times.

  8. Drought-tolerance of wheat improved by rhizosphere bacteria from harsh environments: enhanced biomass production and reduced emissions of stress volatiles.

    Directory of Open Access Journals (Sweden)

    Salme Timmusk

    Full Text Available Water is the key resource limiting world agricultural production. Although an impressive number of research reports have been published on plant drought tolerance enhancement via genetic modifications during the last few years, progress has been slower than expected. We suggest a feasible alternative strategy by application of rhizospheric bacteria coevolved with plant roots in harsh environments over millions of years, and harboring adaptive traits improving plant fitness under biotic and abiotic stresses. We show the effect of bacterial priming on wheat drought stress tolerance enhancement, resulting in up to 78% greater plant biomass and five-fold higher survivorship under severe drought. We monitored emissions of seven stress-related volatiles from bacterially-primed drought-stressed wheat seedlings, and demonstrated that three of these volatiles are likely promising candidates for a rapid non-invasive technique to assess crop drought stress and its mitigation in early phases of stress development. We conclude that gauging stress by elicited volatiles provides an effectual platform for rapid screening of potent bacterial strains and that priming with isolates of rhizospheric bacteria from harsh environments is a promising, novel way to improve plant water use efficiency. These new advancements importantly contribute towards solving food security issues in changing climates.

  9. Investigations into the use of bacteria for enhanced recovery of petroleum; Untersuchungen zum Einsatz von Bakterien zur Erhoehung des Entoelungsgrades in Erdoellagerstaetten

    Energy Technology Data Exchange (ETDEWEB)

    Amro, M.

    1995-06-01

    Strains of bacteria were investigated with a view to their applicability and efficiency in enhanced recovery of petroleum. The mechanisms of enhanced recovery with bacteria were to be clarified as well. The experiments were carried out as static autoclave experiments without bedrock and as dynamic flooding experiments in a model pore space (Bentheim sandstone and carbonate rock) under the conditions of North German petroleum deposits. The static experiments carried out preliminary to the more time-consuming dynamic flooding experiments were to help with an optimized design of the injection experiments. (orig.) [Deutsch] Die vorliegende Arbeit hat zum Ziel, entoelungswirksame Bakterienstaemme zu untersuchen und hinsichtlich der durch sie bewirkten Erhoehung des Entoelungsgrades zu bewerten. Gleichzeitig sollen die Mechanismen aufgeklaert werden, die der Entoelungsverbesserung durch Einsatz von Bakterien zugrunde liegen. Die Experimente wurden als statische Autoklavenversuche ohne Lagerstaettengestein sowie als dynamische Flutversuche im Modellporenraum (Bentheimer Sandstein und karbonatisches Gesteinsmaterial) unter Bedingungen norddeutscher Lagerstaetten durchgefuehrt. Die statischen Versuche, die als Auswahltests den aufwendigeren dynamischen Flutversuchen vorgeschaltet waren, sollten dazu beitragen, die Flutversuche gezielt konzipieren zu koennen. (orig./EF)

  10. Simultaneous inhibition of sulfate-reducing bacteria, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl: Applications for microbial enhanced oil recovery.

    Science.gov (United States)

    Zhao, Feng; Zhou, Ji-Dong; Ma, Fang; Shi, Rong-Jiu; Han, Si-Qin; Zhang, Jie; Zhang, Ying

    2016-05-01

    Sulfate-reducing bacteria (SRB) are widely existed in oil production system, and its H2S product inhibits rhamnolipid producing bacteria. In-situ production of rhamnolipid is promising for microbial enhanced oil recovery. Inhibition of SRB, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl were investigated. Strain Rhl can simultaneously remove S(2-) (>92%) and produce rhamnolipid (>136mg/l) under S(2-) stress below 33.3mg/l. Rhl reduced the SRB numbers from 10(9) to 10(5)cells/ml, and the production of H2S was delayed and decreased to below 2mg/l. Rhl also produced rhamnolipid and removed S(2-) under laboratory simulated oil reservoir conditions. High-throughput sequencing data demonstrated that addition of strain Rhl significantly changed the original microbial communities of oilfield production water and decreased the species and abundance of SRB. Bioaugmentation of strain Rhl in oilfield is promising for simultaneous control of SRB, removal of S(2-) and enhance oil recovery. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Martian Soil Plant Growth Experiment: The Effects of Adding Nitrogen, Bacteria, and Fungi to Enhance Plant Growth

    Science.gov (United States)

    Kliman, D. M.; Cooper, J. B.; Anderson, R. C.

    2000-01-01

    Plant growth is enhanced by the presence of symbiotic soil microbes. In order to better understand how plants might prosper on Mars, we set up an experiment to test whether symbiotic microbes function to enhance plant growth in a Martian soil simulant.

  12. APPLICATION OF METAL RESISTANT BACTERIA BY MUTATIONAL ENHANCMENT TECHNIQUE FOR BIOREMEDIATION OF COPPER AND ZINC FROM INDUSTRIAL WASTES

    Directory of Open Access Journals (Sweden)

    M. R. Shakibaie ، A. Khosravan ، A. Frahmand ، S. Zare

    2008-10-01

    Full Text Available In this research, using mutation in the metal resistant bacteria, the bioremediation of the copper and zinc from copper factory effluents was investigated. Wastewater effluents from flocculation and rolling mill sections of a factory in the city of Kerman were collected and used for further experiments. 20 strains of Pseudomonas spp. were isolated from soil and effluents surrounding factory and identified by microbiological methods. Minimum inhibitory concentrations for copper (Cu and zinc (Zn were determined by agar dilution method. Those strains that exhibited highest minimum inhibitory concentrations values to the metals (5mM were subjected to 400-3200 mg/L concentrations of the three mutagenic agents, acriflavine, acridine orange and ethidium bromide. After determination of subinhibitory concentrations, the minimum inhibitory concentrations values for copper and zinc metal ions were again determined, which showed more than 10 fold increase in minimum inhibitory concentrations value (10 mM for Cu and 20 mM for Zn with P≤0.05. The atomic absorption spectroscopy of dried biomass obtained from resistant strains after exposure to mutagenic agents revealed that strains 13 accumulate the highest amount of intracellular copper (0.35% Cu/mg dried biomass and strain 10 showed highest accumulation of zinc (0.3% Zn/mg dried biomass respectively with P≤0.05. From above results it was concluded that the treatment of industrial waste containing heavy metals by artificially mutated bacteria may be appropriate solution for effluent disposal problems.

  13. Sustainability of Water Reclamation: Long-Term Recharge with Reclaimed Wastewater Does Not Enhance Antibiotic Resistance in Sediment Bacteria

    Directory of Open Access Journals (Sweden)

    Jean E. McLain

    2014-03-01

    Full Text Available Wastewater reclamation for municipal irrigation is an increasingly attractive option for extending water supplies. However, public health concerns include the potential for development of antibiotic resistance (AR in environmental bacteria after exposure to residual pharmaceuticals in reclaimed water. Though scientific studies have reported high levels of AR in soils irrigated with wastewater, these works often fail to address the soil resistome, or the natural occurrence of AR. This study compared AR patterns in sediment Enterococcus isolated from water storage basins containing either reclaimed water or groundwater in central Arizona. Resistance to 16 antibiotics was quantified in isolates to a depth of 30 cm. Results reveal high levels of resistance to certain antibiotics, including lincomycin, ciprofloxacin, and erythromycin, exists in sediments regardless of the water source (groundwater, reclaimed water, and higher AR was not detectable in reclaimed water sediments. Furthermore, multiple-antibiotic-resistance (MAR was substantially reduced in isolates from reclaimed water sediments, compared to freshwater sediment isolates. Comparing the development of AR in sediment bacteria at these two sites will increase awareness of the environmental and public health impacts of using reclaimed water for irrigation of municipal areas, and illustrates the necessity for control sites in studies examining AR development in environmental microbiota.

  14. Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management

    Science.gov (United States)

    Palmqvist, N. G. M.; Bejai, S.; Meijer, J.; Seisenbaeva, G. A.; Kessler, V. G.

    2015-05-01

    A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection.

  15. Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment.

    Science.gov (United States)

    Tong, Juan; Liu, Jibao; Zheng, Xiang; Zhang, Junya; Ni, Xiaotang; Chen, Meixue; Wei, Yuansong

    2016-10-01

    The fate of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were investigated during the sludge anaerobic digestion (AD) with microwave-acid (MW-H), microwave (MW) and microwave-H2O2-alkaline (MW-H2O2) pretreatments. Results showed that combined MW pretreatment especially for the MW-H pretreatment could efficiently reduce the ARB concentration, and most ARG concentrations tended to attenuate during the pretreatment. The subsequent AD showed evident removal of the ARB, but most ARGs were enriched after AD. Only the concentration of tetX kept continuous declination during the whole sludge treatment. The total ARGs concentration showed significant correlation with 16S rRNA during the pretreatment and AD. Compared with unpretreated sludge, the AD of MW and MW-H2O2 pretreated sludge presented slightly better ARB and ARGs reduction efficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Enhanced biological stabilization of heavy metals in sediment using immobilized sulfate reducing bacteria beads with inner cohesive nutrient

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin, E-mail: hgxlixin@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Dai, Lihua; Zhang, Chang; Zeng, Guangming; Liu, Yunguo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Zhou, Chen [Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University (United States); Xu, Weihua; Wu, Youe; Tang, Xinquan; Liu, Wei; Lan, Shiming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

    2017-02-15

    Highlights: • Nutrient beads of immobilized SRB were more effective in transforming heavy metals into the more stable bound phases. • Inner cohesive nutrient effectively promoted the stabilization process of heavy metals. • The excellent removal efficiencies of Cu, Zn, Pb and Cd were 76.3%, 95.6%, 100% and 91.2%, respectively. • Easy to recycle and avoid secondary pollution. - Abstract: A series of experiments were conducted for treating heavy metals contaminated sediments sampled from Xiangjiang River, which combined polyvinyl alcohol (PVA) and immobilized sulfate reducing bacteria (SRB) into beads. The sodium lactate was served as the inner cohesive nutrient. Coupling the activity of the SRB with PVA, along with the porous structure and huge specific surface area, provided a convenient channel for the transmission of matter and protected the cells against the toxicity of metals. This paper systematically investigated the stability of Cu, Zn, Pb and Cd and its mechanisms. The results revealed the performance of leaching toxicity was lower and the removal efficiencies of Cu, Zn, Pb and Cd were 76.3%, 95.6%, 100% and 91.2%, respectively. Recycling experiments showed the beads could be reused 5 times with superbly efficiency. These results were also confirmed by continuous extraction at the optimal conditions. Furthermore, X-ray diffraction (XRD) and energy-dispersive spectra (EDS) analysis indicated the heavy metals could be transformed into stable crystal texture. The stabilization of heavy metals was attributed to the carbonyl and acyl amino groups. Results presented that immobilized bacteria with inner nutrient were potentially and practically applied to multi-heavy-metal-contamination sediment.

  17. Enhancement of microbial quality and inactivation of pathogenic bacteria by gamma irradiation of ready-to-cook Iranian barbecued chicken

    Science.gov (United States)

    Fallah, Aziz A.; Siavash Saei-Dehkordi, S.; Rahnama, Mohammad

    2010-10-01

    Ready-to-cook Iranian barbecued chicken consists of cubed chicken breast, lemon juice, salt, red pepper, onion, saffron and vegetable oil with an overall pH value of about 5.5. This product is sometimes consumed under-cooked, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. In this study, the effect of gamma irradiation (0, 1.5, 3 and 4.5 kGy) on the microbial quality of ready-to-cook (RTC) barbecued chicken samples stored at 4 °C for 15 days was investigated. Moreover, the effectiveness of irradiation for inactivating Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella typhimurium inoculated into the samples was also studied. Irradiation of the samples resulted in dose dependent reduction in counts of aerobic mesophilic bacteria, yeasts and molds, Enterobacteriaceae and lactic acid bacteria. Among the microbial flora, yeasts and molds and Enterobacteriaceae were more sensitive to irradiation and got completely eliminated at dose of 3 kGy. D10 values of L. monocytogenes, E. coli O157:H7 and S. typhimurium inoculated into the samples were 0.680, 0.397 and 0.601 kGy, respectively. An irradiation dose of 3 kGy reduced the counts of E. coli O157:H7 to an undetectable level in RTC barbecued chicken but was ineffective on elimination of L. monocytogenes and S. typhimurium. However, none of the food-borne pathogens were detected in the samples irradiated at 4.5 kGy. This study showed that irradiation had no undesirable effects on the initial sensory attributes of barbecued chicken. At the end of the storage period, irradiated samples were more acceptable compared to non-irradiated ones.

  18. Enhancement of microbial quality and inactivation of pathogenic bacteria by gamma irradiation of ready-to-cook Iranian barbecued chicken

    International Nuclear Information System (INIS)

    Fallah, Aziz A.; Siavash Saei-Dehkordi, S.; Rahnama, Mohammad

    2010-01-01

    Ready-to-cook Iranian barbecued chicken consists of cubed chicken breast, lemon juice, salt, red pepper, onion, saffron and vegetable oil with an overall pH value of about 5.5. This product is sometimes consumed under-cooked, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. In this study, the effect of gamma irradiation (0, 1.5, 3 and 4.5 kGy) on the microbial quality of ready-to-cook (RTC) barbecued chicken samples stored at 4 o C for 15 days was investigated. Moreover, the effectiveness of irradiation for inactivating Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella typhimurium inoculated into the samples was also studied. Irradiation of the samples resulted in dose dependent reduction in counts of aerobic mesophilic bacteria, yeasts and molds, Enterobacteriaceae and lactic acid bacteria. Among the microbial flora, yeasts and molds and Enterobacteriaceae were more sensitive to irradiation and got completely eliminated at dose of 3 kGy. D 10 values of L. monocytogenes, E. coli O157:H7 and S. typhimurium inoculated into the samples were 0.680, 0.397 and 0.601 kGy, respectively. An irradiation dose of 3 kGy reduced the counts of E. coli O157:H7 to an undetectable level in RTC barbecued chicken but was ineffective on elimination of L. monocytogenes and S. typhimurium. However, none of the food-borne pathogens were detected in the samples irradiated at 4.5 kGy. This study showed that irradiation had no undesirable effects on the initial sensory attributes of barbecued chicken. At the end of the storage period, irradiated samples were more acceptable compared to non-irradiated ones.

  19. Enhancement of microbial quality and inactivation of pathogenic bacteria by gamma irradiation of ready-to-cook Iranian barbecued chicken

    Energy Technology Data Exchange (ETDEWEB)

    Fallah, Aziz A., E-mail: a_a_falah@yahoo.co [Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahre-Kord University, Shahre-Kord 34141 (Iran, Islamic Republic of); Research Institute of Zoonotic Diseases, Shahre-Kord University, Shahre-Kord 34141 (Iran, Islamic Republic of); Siavash Saei-Dehkordi, S. [Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahre-Kord University, Shahre-Kord 34141 (Iran, Islamic Republic of); Research Institute of Zoonotic Diseases, Shahre-Kord University, Shahre-Kord 34141 (Iran, Islamic Republic of); Rahnama, Mohammad [Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, University of Zabol, Zabol 98615 (Iran, Islamic Republic of)

    2010-10-15

    Ready-to-cook Iranian barbecued chicken consists of cubed chicken breast, lemon juice, salt, red pepper, onion, saffron and vegetable oil with an overall pH value of about 5.5. This product is sometimes consumed under-cooked, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. In this study, the effect of gamma irradiation (0, 1.5, 3 and 4.5 kGy) on the microbial quality of ready-to-cook (RTC) barbecued chicken samples stored at 4 {sup o}C for 15 days was investigated. Moreover, the effectiveness of irradiation for inactivating Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella typhimurium inoculated into the samples was also studied. Irradiation of the samples resulted in dose dependent reduction in counts of aerobic mesophilic bacteria, yeasts and molds, Enterobacteriaceae and lactic acid bacteria. Among the microbial flora, yeasts and molds and Enterobacteriaceae were more sensitive to irradiation and got completely eliminated at dose of 3 kGy. D{sub 10} values of L. monocytogenes, E. coli O157:H7 and S. typhimurium inoculated into the samples were 0.680, 0.397 and 0.601 kGy, respectively. An irradiation dose of 3 kGy reduced the counts of E. coli O157:H7 to an undetectable level in RTC barbecued chicken but was ineffective on elimination of L. monocytogenes and S. typhimurium. However, none of the food-borne pathogens were detected in the samples irradiated at 4.5 kGy. This study showed that irradiation had no undesirable effects on the initial sensory attributes of barbecued chicken. At the end of the storage period, irradiated samples were more acceptable compared to non-irradiated ones.

  20. Influence of Gamma Radiation on the Treatment of Sulfate Reducing Bacteria in the Injection Water Used for the Enhanced Oil Recovery

    International Nuclear Information System (INIS)

    El-Shahawy, M.R.; Ramzi, M.; Farag, R.M.

    2014-01-01

    The counts of sulfate reducing bacteria (SRB) in the water samples collected from the well head (formation water) and outlet of petroleum treatment plant (Produced water) in a petroleum field in middle delta- Egypt were determined. The data showed a low count of (SRB) in the collected formation water sample and there was an obvious increase in the bacterial counts which appeared in the produced water, that may reveal that the presence of appropriate conditions for the growth of (SRB) in the closed system in treatment plant. Two scale inhibitors were tested through jar test, the scale inhibitor I had maximum efficiency at 20 ppm, two SRB biocides were screened for their bactericidal activities. It was found that the biocides A was slightly superior in respect to the antibacterial efficacy compared to B in presence of 20 ppm scale inhibitor. These biocides were test for the study of the combined treatment with gamma radiation to maximize the efficiency on sulfate reducing bacteria using the minimum effective dose of both radiation and biocides to eliminate the negative impacts of the chemicals used and the radiation applied. The results demonstrated that, the lethal doses of biocides were (300 ppm) of biocides A or (400 ppm) of biocides B at 1 kGy irradiation dose. The treated produced water was evaluated in respect of enhanced oil recovery, the data showed increase of the recovery capacity by the irradiation and chemical treatment. This technology could be used for the water that are injected into reservoirs, and suitable for oil field and pipeline operators, and presented a viable bacteria control method

  1. Contribution of arbuscular mycorrhizal fungi and/or bacteria to enhancing plant drought tolerance under natural soil conditions: effectiveness of autochthonous or allochthonous strains.

    Science.gov (United States)

    Ortiz, N; Armada, E; Duque, E; Roldán, A; Azcón, R

    2015-02-01

    Autochthonous microorganisms [a consortium of arbuscular-mycorrhizal (AM) fungi and Bacillus thuringiensis (Bt)] were assayed and compared to Rhizophagus intraradices (Ri), Bacillus megaterium (Bm) or Pseudomonas putida (Psp) and non-inoculation on Trifolium repens in a natural arid soil under drought conditions. The autochthonous bacteria Bt and the allochthonous bacteria Psp increased nutrients and the relative water content and decreased stomatal conductance, electrolyte leakage, proline and APX activity, indicating their abilities to alleviate the drought stress. Mycorrhizal inoculation significantly enhanced plant growth, nutrient uptake and the relative water content, particularly when associated with specific bacteria minimizing drought stress-imposed effects. Specific combinations of autochthonous or allochthonous inoculants also contributed to plant drought tolerance by changing proline and antioxidative activities. However, non-inoculated plants had low relative water and nutrients contents, shoot proline accumulation and glutathione reductase activity, but the highest superoxide dismutase activity, stomatal conductance and electrolyte leakage. Microbial activities irrespective of the microbial origin seem to be coordinately functioning in the plant as an adaptive response to modulated water stress tolerance and minimizing the stress damage. The autochthonous AM fungi with Bt or Psp and those allochthonous Ri with Bm or Psp inoculants increased water stress alleviation. The autochthonous Bt showed the greatest ability to survive under high osmotic stress compared to the allochthonous strains, but when single inoculated or associated with Ri or AM fungi were similarly efficient in terms of physiological and nutritional status and in increasing plant drought tolerance, attenuating and compensating for the detrimental effect of water limitation. Copyright © 2014 Elsevier GmbH. All rights reserved.

  2. Probiotic potential of Bacillus velezensis JW: Antimicrobial activity against fish pathogenic bacteria and immune enhancement effects on Carassius auratus.

    Science.gov (United States)

    Yi, Yanglei; Zhang, Zhenhua; Zhao, Fan; Liu, Huan; Yu, Lijun; Zha, Jiwei; Wang, Gaoxue

    2018-04-24

    This study evaluated the probiotic potential of B. velezensis JW through experimental and genomic analysis approaches. Strain JW showed antimicrobial activity against a broad range of fish pathogenic bacteria including Aeromonas hydrophila, Aeromonas salmonicida, Lactococcus garvieae, Streptococcus agalactiae, and Vibrio Parahemolyticus. Fish (Carassius auratus) were fed with the diets containing 0 (control), 10 7 , and 10 9  cfu/g of B. velezensis JW for 4 weeks. Various immune parameters were examined at 1, 2, 3, and 4 weeks of post-feeding. Results showed that JW supplemented diets significantly increased acid phosphatase (ACP), alkaline phosphatase (AKP), and glutathione peroxidase (GSH-PX) activity. The mRNA expression of immune-related genes in the head kidney of C. auratus was measured. Among them, the interferon gamma gene (IFN- γ) and tumor necrosis factor-α (TNF-α) showed higher expression after 3 and 4 weeks of feeding (P velezensis JW has the potential to be developed as a probiotic agent in aquaculture. Copyright © 2018. Published by Elsevier Ltd.

  3. Chemical conjugation of 2-hexadecynoic acid to C5-curcumin enhances its antibacterial activity against multi-drug resistant bacteria.

    Science.gov (United States)

    Sanabria-Ríos, David J; Rivera-Torres, Yaritza; Rosario, Joshua; Gutierrez, Ricardo; Torres-García, Yeireliz; Montano, Nashbly; Ortíz-Soto, Gabriela; Ríos-Olivares, Eddy; Rodríguez, José W; Carballeira, Néstor M

    2015-11-15

    The first total synthesis of a C5-curcumin-2-hexadecynoic acid (C5-Curc-2-HDA, 6) conjugate was successfully performed. Through a three-step synthetic route, conjugate 6 was obtained in 13% overall yield and tested for antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) strains. Our results revealed that 6 was active against eight MRSA strains at MICs that range between 31.3 and 62.5 μg/mL. It was found that the presence of 2-hexadecynoic acid (2-HDA, 4) in conjugate 6 increased 4-8-fold its antibacterial activity against MRSA strains supporting our hypothesis that the chemical connection of 4 to C5-curcumin (2) increases the antibacterial activity of 2 against Gram-positive bacteria. Combinational index (CIn) values that range between 1.6 and 2.3 were obtained when eight MRSA strains were treated with an equimolar mixture of 2 and 4. These results demonstrated that an antagonistic effect is taking place. Finally, it was investigated whether conjugate 6 can affect the replication process of S. aureus, since this compound inhibited the supercoiling activity of the S. aureus DNA gyrase at minimum inhibitory concentrations (MIC) of 250 μg/mL (IC50=100.2±13.9 μg/mL). Moreover, it was observed that the presence of 4 in conjugate 6 improves the anti-topoisomerase activity of 2 towards S. aureus DNA gyrase, which is in agreement with results obtained from antibacterial susceptibility tests involving MRSA strains. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Yerba mate enhances probiotic bacteria growth in vitro but as a feed additive does not reduce Salmonella Enteritidis colonization in vivo.

    Science.gov (United States)

    Gonzalez-Gil, Francisco; Diaz-Sanchez, Sandra; Pendleton, Sean; Andino, Ana; Zhang, Nan; Yard, Carrie; Crilly, Nate; Harte, Federico; Hanning, Irene

    2014-02-01

    Yerba mate (Ilex paraguariensis) is a tea known to have beneficial effects on human health and antimicrobial activity against some foodborne pathogens. Thus, the application of yerba mate as a feed additive for broiler chickens to reduce Salmonella colonization was evaluated. The first in vitro evaluation was conducted by suspending Salmonella Enteritidis and lactic acid bacteria (LAB) in yerba mate extract. The in vivo evaluations were conducted using preventative and horizontal transmission experiments. In all experiments, day-of-hatch chicks were treated with one of the following 1) no treatment (control); 2) ground yerba mate in feed; 3) probiotic treatment (Lactobacillus acidophilus and Pediococcus; 9:1 administered once on day of hatch by gavage); or 4) both yerba mate and probiotic treatments. At d 3, all chicks were challenged with Salmonella Enteritidis (preventative experiment) or 5 of 20 chicks (horizontal transmission experiment). At d 10, all birds were euthanized, weighed, and cecal contents enumerated for Salmonella. For the in vitro evaluation, antimicrobial activity was observed against Salmonella and the same treatment enhanced growth of LAB. For in vivo evaluations, none of the yerba mate treatments significantly reduced Salmonella Enteritidis colonization, whereas the probiotic treatment significantly reduced Salmonella colonization in the horizontal transmission experiment. Yerba mate decreased chicken BW and decreased the performance of the probiotic treatment when used in combination. In conclusion, yerba mate had antimicrobial activity against foodborne pathogens and enhanced the growth of LAB in vitro, but in vivo yerba mate did not decrease Salmonella Enteritidis colonization.

  5. Concomitant ingestion of lactic acid bacteria and black tea synergistically enhances flavonoid bioavailability and attenuates d-galactose-induced oxidative stress in mice via modulating glutathione antioxidant system.

    Science.gov (United States)

    Zhao, Danyue; Shah, Nagendra P

    2016-12-01

    Black tea (BT) has been positively linked to improved redox status, while its efficacy is limited due to the low bioavailability of BT flavonoids. In addition to the direct antioxidant activity, flavonoids regulate redox balance via inducing endogenous antioxidants, particularly glutathione (GSH) and GSH-dependent antioxidant enzymes. This work first examined the effect of lactic acid bacteria (LAB) and BT alone or in combination on flavonoid bioavailability and metabolism; next, the effect of LAB-fermented BT diet in attenuating oxidative stress in mice and the underlying mechanisms were studied. Phenolic profiles of plasma, urine and feces from healthy mice consuming plain yogurt, BT milk (BTM) or BT yogurt (BTY) were acquired using LC-MS/MS. Plasma antioxidant capacity, lipid peroxidation level, content of nonprotein thiols and expression of GSH-related antioxidant enzymes and Nrf2 were examined in d-galactose-treated mice. Total flavonoid content in plasma following a single dose of BTY attained 0.657 μmol/l, increased by 50% compared with the BTM group. Increased excretion of phenolic metabolite and hippuric acid in urine and feces indicated enhanced metabolism of flavonoids in BTY-fed mice. In the second study, 8-week concomitant LAB-BT treatment of oxidatively stressed mice effectively restored plasma antioxidant capacity and GSH levels, and mitigated lipid peroxidation, which were associated with significant induction of GSH-dependent antioxidant enzymes and nuclear accumulation of Nrf2. Our results demonstrated the effect of LAB fermentation in enhancing BT flavonoid bioavailability in vivo. The synergistic antioxidant efficacy of LAB-BT diet implied its therapeutic potential in enhancing antioxidant defenses and protecting organisms from oxidative damage. Copyright © 2016. Published by Elsevier Inc.

  6. Effect of probiotic bacteria-fermented medicinal plants (Gynura procumbens, Rehmannia glutinosa, Scutellaria baicalensis) as performance enhancers in growing pigs.

    Science.gov (United States)

    Jeong, Jin Suk; Kim, In Ho

    2015-06-01

    This study was conducted to investigate the effect of dietary supplementation of mixed fermented medicinal plants (FMP) obtained from exudates of Gynura procumbens, Rehmannia glutinosa and Scutellaria baicalensis fermented with Lactobacillus plantarum, Saccharomyces cerevisiae and Bacillus licheniformis, respectively, on growth performance in growing pigs in order to assess the feasibility of using FMP as an alternative to antibiotic growth promoters (AGP), such as tiamulin. A total of 150 growing pigs (body wieght 25.50 ± 2.50 kg) were used in a 6 weeks experiment and randomly divided into five groups with six replicates of five growing pigs each. The treatments were NC (basal diet), basal diet with 33 ppm tiamulin (PC), basal diet with FMP 0.05% (FMP 0.05), basal diet with FMP 0.1% (FMP 0.1) and basal diet with FMP 0.2% (FMP 0.2). Overall, body weight gain, feed conversion rate, the digestibility of dry matter and gross energy, noxious gas emission all improved with FMP supplementation as compared to NC. Taken together, these results suggest the feasibility of using FMP as an alternative to AGP for enhancing the growth performance, nutrient digestibility and excreta noxious gas emission of growing pigs. © 2014 Japanese Society of Animal Science.

  7. Autologous albumin enhances the humoral immune response to capsular polysaccharide covalently co-attached to bacteria-sized latex beads

    Science.gov (United States)

    Colino, Jesus; Duke, Leah; Snapper, Clifford M.

    2014-01-01

    Abundant autologous proteins, like serum albumin, should be immunologically inert. However, individuals with no apparent predisposition to autoimmune disease can develop immune responses to autologous therapeutic proteins. Protein aggregation is a potential major trigger of these responses. Adsorption of proteins to particles provides macromolecular size and may generate structural changes in the protein, resembling aggregation. Using aldehyde/sulfate latex beads coated with murine serum albumin (MSA), we found that mice mounted MSA-specific IgG responses that were dependent on CD4+ T cells. IgG were specific for MSA adsorbed to solid surfaces and non-cross-reactive with human, bovine or pig albumins. T cells induced in response to MSA, augmented the primary and induced boosted secondary IgG and IgM responses specific for the T cell-independent antigen, capsular polysaccharide of Streptococcus pneumoniae type 14 (PPS14), when the latter was attached to the same bead. Similar to the anti-MSA IgG response, the boosted PPS14-specific IgG secondary response was CD4+ T cell-dependent, displayed a typical carrier effect, and was enhanced by, but did not require, Toll-like receptor stimulation. These results provide a potential mechanism for the induction of responses to autoantigens unable to induce specific T cell responses, and provide new insights into polysaccharide-specific immunity. PMID:24481921

  8. Enhancement of the immune response and protection induced by probiotic lactic acid bacteria against furunculosis in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Balcázar, José Luis; de Blas, Ignacio; Ruiz-Zarzuela, Imanol; Vendrell, Daniel; Gironés, Olivia; Muzquiz, José Luis

    2007-10-01

    We analysed the effect of probiotic strains on the cellular and humoral immune responses of rainbow trout (Oncorhynchus mykiss), and their capacity to prevent furunculosis during a challenge trial. Probiotic strains (Lactococcus lactis ssp. lactis CLFP 100, Leuconostoc mesenteroides CLFP 196, and Lactobacillus sakei CLFP 202) were administered orally to fish for 2 weeks at 10(6) CFU g(-1) of feed. In comparison to untreated control fish, the phagocytic activity of head kidney leukocytes and the alternative complement activity in serum were significantly greater in all probiotic groups at the end of the second week. With the exception of the group fed with Lactobacillus sakei, superoxide anion production was also significantly increased in the probiotic groups. Analysis of lysozyme activity did not exhibit any significant difference in the probiotic and control groups. Fifteen days after the start of the probiotic feeding, fish were challenged with Aeromonas salmonicida ssp. salmonicida. The fish supplemented with probiotics exhibited survival rates ranging from 97.8% to 100%, whereas survival was 65.6% in fish not treated with the probiotics. These results demonstrate that probiotic supplementation to fish can reduce the severity of furunculosis, and suggest that this reduction may be associated with enhanced humoral and cellular immune response.

  9. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria...

  10. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria......, the 80 x 600 mum large Epulopiscium sp. from the gut of tropical fish, are presumably living in a very nutrient-rich medium. Many large bacteria contain numerous inclusions in the cells that reduce the volume of active cytoplasm. The most striking examples of competitive advantage from large cell size...

  11. Magnetic Bacteria.

    Science.gov (United States)

    Nelson, Jane Bray; Nelson, Jim

    1992-01-01

    Describes the history of Richard Blakemore's discovery of magnetotaxic organisms. Discusses possible reasons why the magnetic response in bacteria developed. Proposes research experiments integrating biology and physics in which students investigate problems using cultures of magnetotaxic organisms. (MDH)

  12. Do bacteria, not fish, produce 'fish kairomone'?

    NARCIS (Netherlands)

    Ringelberg, J.; Van Gool, E.

    1998-01-01

    Fish-associated chemicals enhance phototactic downward swimming in Daphnia. If perch were treated with the antibiotic ampicillin, this enhancement was significantly decreased. Therefore, not fish, but bacteria associated with fish, seem to produce this kairomone. [KEYWORDS: Diel vertical migration;

  13. Review on SERS of Bacteria

    Directory of Open Access Journals (Sweden)

    Pamela A. Mosier-Boss

    2017-11-01

    Full Text Available Surface enhanced Raman spectroscopy (SERS has been widely used for chemical detection. Moreover, the inherent richness of the spectral data has made SERS attractive for use in detecting biological materials, including bacteria. This review discusses methods that have been used to obtain SERS spectra of bacteria. The kinds of SERS substrates employed to obtain SERS spectra are discussed as well as how bacteria interact with silver and gold nanoparticles. The roll of capping agents on Ag/Au NPs in obtaining SERS spectra is examined as well as the interpretation of the spectral data.

  14. Antibacterial Surface Design of Titanium-Based Biomaterials for Enhanced Bacteria-Killing and Cell-Assisting Functions Against Periprosthetic Joint Infection.

    Science.gov (United States)

    Wang, Jiaxing; Li, Jinhua; Qian, Shi; Guo, Geyong; Wang, Qiaojie; Tang, Jin; Shen, Hao; Liu, Xuanyong; Zhang, Xianlong; Chu, Paul K

    2016-05-04

    Periprosthetic joint infection (PJI) is one of the formidable and recalcitrant complications after orthopedic surgery, and inhibiting biofilm formation on the implant surface is considered crucial to prophylaxis of PJI. However, it has recently been demonstrated that free-floating biofilm-like aggregates in the local body fluid and bacterial colonization on the implant and peri-implant tissues can coexist and are involved in the pathogenesis of PJI. An effective surface with both contact-killing and release-killing antimicrobial capabilities can potentially abate these concerns and minimize PJI caused by adherent/planktonic bacteria. Herein, Ag nanoparticles (NPs) are embedded in titania (TiO2) nanotubes by anodic oxidation and plasma immersion ion implantation (PIII) to form a contact-killing surface. Vancomycin is then incorporated into the nanotubes by vacuum extraction and lyophilization to produce the release-killing effect. A novel clinical PJI model system involving both in vitro and in vivo use of methicillin-resistant Staphylococcus aureus (MRSA) ST239 is established to systematically evaluate the antibacterial properties of the hybrid surface against planktonic and sessile bacteria. The vancomycin-loaded and Ag-implanted TiO2 nanotubular surface exhibits excellent antimicrobial and antibiofilm effects against planktonic/adherent bacteria without appreciable silver ion release. The fibroblasts/bacteria cocultures reveal that the surface can help fibroblasts to combat bacteria. We first utilize the nanoarchitecture of implant surface as a bridge between the inorganic bactericide (Ag NPs) and organic antibacterial agent (vancomycin) to achieve total victory in the battle of PJI. The combination of contact-killing and release-killing together with cell-assisting function also provides a novel and effective strategy to mitigate bacterial infection and biofilm formation on biomaterials and has large potential in orthopedic applications.

  15. Rumen bacteria

    International Nuclear Information System (INIS)

    McSweeney, C.S.; Denman, S.E.; Mackie, R.I.

    2005-01-01

    The rumen is the most extensively studied gut community and is characterized by its high population density, wide diversity and complexity of interactions. This complex, mixed microbial culture is comprised of prokaryote organisms including methane-producing archaebacteria, eukaryote organisms, such as ciliate and flagellate protozoa, anaerobic phycomycete fungi and bacteriophage. Bacteria are predominant (up to 10 11 viable cells per g comprising 200 species) but a variety of ciliate protozoa occur widely (10 4 -10 6 /g distributed over 25 genera). The anaerobic fungi are also widely distributed (zoospore population densities of 10 2 -10 4 /g distributed over 5 genera). The occurrence of bacteriophage is well documented (10 7 -10 9 particles/g). This section focuses primarily on the widely used methods for the cultivation and the enumeration of rumen microbes, especially bacteria, which grow under anaerobic conditions. Methods that can be used to measure hydrolytic enzymes (cellulases, xylanases, amylases and proteinases) are also described, along with cell harvesting and fractionation procedures. Brief reference is also made to fungi and protozoa, but detailed explanations for culturing and enumerating these microbes is presented in Chapters 2.4 and 2.5

  16. Application of Gamma Radiation to Enhance Heavy Metals Removal Efficiency to Bacteria Isolated from Ronpiboon District, Nakhon Sri Thamarat Province, Thailand

    International Nuclear Information System (INIS)

    Intrasungkha, Nugul; Wisapan, Walakon; Piadang, Nattayana

    2006-09-01

    The objective of this study was to isolate soil bacteria capable to te move 4 heavy metals, namely, arsenic (As(III)), lead Pb(II) and cadmium f ron old tin mine in Ronpiboon district, Nakhon Sri Thamarat. It was found that there were bacteria which capable to resist arsenic, lead and copper 11, 15, 8 and 2 ileitis, respectively[evacuate;y. The arsenic removal efficiency of these bacteria was evaluated at the low concentration of 1 u g/l. with the results of 7-61%. The lead and copper removal efficiencies at 10 mg/l were found at the range pf 9-98% and 8-40%, respectively. Six isolates of bacteria (KRD, KRH, KRM, KCD13 and KCD14) were selected to be irradiated by gamma radiation at the levels of 2-10 kGy. The heavy metals resistance was found increase in the range of of 125-16% for arsenic, 0-50% for copper, 0-18% for lead and 0-17% for cadmium, respectively. Also ut was found that the low temperature at 4 and -40 degree Celsius can prolong the bacterial survival up to 6 months. Later the arsenic removal experiment in liquid medium was conducted and it was found that the mutants can perform slightly better than wild type only >17%. It was due to the initial concentration of arsenic was too high (10 mg/l). The preliminary study of arsenic removal in soil was also conducted using pack-bed reactor. We found the proper ratio of pack material (soil and gravel) was 1:1 to promote the liquid and air circulation. The suitable medium was found to be acidified mo lass solution which were found promote the growth of tested bacterial isolates.

  17. Facile synthesis of gold nanoparticles on propylamine functionalized SBA-15 and effect of surface functionality of its enhanced bactericidal activity against gram positive bacteria

    International Nuclear Information System (INIS)

    Bhuyan, Diganta; Saikia, Mrinal; Saikia, Lakshi; Gogoi, Animesh; Saikia, Ratul

    2015-01-01

    The facile synthesis of an SBA-15-pr- + NH 3 .Au 0 nano-hybrid material by spontaneous autoreduction of aqueous chloroaurate anions on propylamine functionalized SBA-15 was successfully demonstrated. The as-synthesized SBA-15-pr- + NH 3 .Au 0 nano-hybrid material was well characterized using low and wide angle x-ray diffraction (XRD), N 2 adsorption–desorption isotherms, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX), x-ray photoelectron spectroscopy (XPS), UV-Visible spectroscopy and atomic absorption spectroscopy (AAS). The activity of the nano-hybrid material as a potent bactericidal agent was successfully tested against Gram positive/negative bacteria viz. Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The colony killing percentage of Gram positive bacteria was found to be higher than Gram negative bacteria due to the stronger electrostatic interaction between the positively-charged amine functionality of SBA-15 and the negatively charged functionality of the bacterial cell wall. (paper)

  18. Interactions of rice (Oryza sativa L.) and PAH-degrading bacteria (Acinetobacter sp.) on enhanced dissipation of spiked phenanthrene and pyrene in waterlogged soil.

    Science.gov (United States)

    Gao, Y; Yu, X Z; Wu, S C; Cheung, K C; Tam, N F Y; Qian, P Y; Wong, M H

    2006-12-15

    The effects of cultivation of rice (Oryza sativa L.) and PAH-degrading bacteria (Acinetobacter sp.) separately, and in combination, on the dissipation of spiked phenanthrene and pyrene (0, 50+50, 100+100, 200+200 mg kg(-1)) in waterlogged soil were studied using pot trials. The population of introduced PAH-degrading bacteria remained at 10(5) CFU g(-1) dry soil after 20 days of treatment with Acinetobacter sp. only, but increased to 10(6) when planted with rice simultaneously. Shoot and root biomass of rice when grown alone was adversely affected by spiked PAHs, but significantly increased by 2-55% and 8-409%, respectively, when inoculated with Acinetobacter sp.. Phenanthrene and pyrene concentrations in roots ranged from 1-27 and 20-98 mg kg(-1), respectively, while their concentrations in shoots were generally lower than 0.2 mg kg(-1). The dissipation of phenanthrene was mainly due to abiotic loss as 70-78% phenanthrene was lost from the control soil at the end of 80 days, while removal of 86-87% phenanthrene had been achieved after 40 days in the treatment co-cultivated with Acinetobacter sp. and rice. Compared with the control where only 6-15% of pyrene was removed from soil, a much higher dissipation of pyrene (43-62%) was attained for the treatments co-cultivated with Acinetobacter sp. and rice at the end of 80 days. The results demonstrated that co-cultivation of rice and PAH-degrading bacteria may have a great potential to accelerate the bioremediation process of PAH-contaminated soil under waterlogged conditions.

  19. The Effect of Fermentation Time with Probiotic Bacteria on Organic Fertilizer as Daphnia magna Cultured Medium towards Nutrient Quality, Biomass Production and Growth Performance Enhancement

    Science.gov (United States)

    Endar Herawati, Vivi; Agung Nugroho, Ristiawan; Pinandoyo; Darmanto, YS; Hutabarat, Johannes

    2018-02-01

    The nutrient quality and growth performance of D. magna are highly depend on the organic fertilizer which is used in its culture medium. The objective of this study was to identify the best fermentation time by using probiotic bacteria on organic fertilizer as mass culture medium to improve its nutrient quality, biomass production, and growth performance. This study was conducted using completely randomized experimental design with five treatments and three repetitions. Organic fertilizers used cultured medium with chicken manure, rejected bread and tofu waste fermented by probiotic bacteria then cultured for 0, 7, 14, 21 and 28 days. The results showed that medium which used 25% chicken manure, 25% tofu waste and 50% rejected bread cultured for 28 days created the highest biomass production, population density and nutrient content of D. magna those are 233,980 ind/L for population density; 134.60 grams for biomass production, 0.574% specific growth rate; 68.06% protein content and 6.91% fat. The highest fatty acid profile is 4.83% linoleic and 3.54% linolenic acid. The highest essential amino acid is 53.94 ppm lysine. In general, the content of ammonia, DO, temperature, and pH during the study were in the good range of D. magna life. The conclusion of this research is medium which used 25% chicken manure, 25% tofu waste and 50% rejected bread cultured for 28 days created the highest biomass production, population and nutrient content of D. magna.

  20. Enhanced

    Directory of Open Access Journals (Sweden)

    Martin I. Bayala

    2014-06-01

    Full Text Available Land Surface Temperature (LST is a key parameter in the energy balance model. However, the spatial resolution of the retrieved LST from sensors with high temporal resolution is not accurate enough to be used in local-scale studies. To explore the LST–Normalised Difference Vegetation Index relationship potential and obtain thermal images with high spatial resolution, six enhanced image sharpening techniques were assessed: the disaggregation procedure for radiometric surface temperatures (TsHARP, the Dry Edge Quadratic Function, the Difference of Edges (Ts∗DL and three models supported by the relationship of surface temperature and water stress of vegetation (Normalised Difference Water Index, Normalised Difference Infrared Index and Soil wetness index. Energy Balance Station data and in situ measurements were used to validate the enhanced LST images over a mixed agricultural landscape in the sub-humid Pampean Region of Argentina (PRA, during 2006–2010. Landsat Thematic Mapper (TM and Moderate Resolution Imaging Spectroradiometer (EOS-MODIS thermal datasets were assessed for different spatial resolutions (e.g., 960, 720 and 240 m and the performances were compared with global and local TsHARP procedures. Results suggest that the Ts∗DL technique is the most adequate for simulating LST to high spatial resolution over the heterogeneous landscape of a sub-humid region, showing an average root mean square error of less than 1 K.

  1. Use of sourdough made with quinoa (Chenopodium quinoa) flour and autochthonous selected lactic acid bacteria for enhancing the nutritional, textural and sensory features of white bread.

    Science.gov (United States)

    Rizzello, Carlo Giuseppe; Lorusso, Anna; Montemurro, Marco; Gobbetti, Marco

    2016-06-01

    Lactic acid bacteria were isolated and identified from quinoa flour, spontaneously fermented quinoa dough, and type I quinoa sourdough. Strains were further selected based on acidification and proteolytic activities. Selected Lactobacillus plantarum T6B10 and Lactobacillus rossiae T0A16 were used as mixed starter to get quinoa sourdough. Compared to non-fermented flour, organic acids, free amino acids, soluble fibers, total phenols, phytase and antioxidant activities, and in vitro protein digestibility markedly increased during fermentation. A wheat bread was made using 20% (w/w) of quinoa sourdough, and compared to baker's yeast wheat breads manufactured with or without quinoa flour. The use of quinoa sourdough improved the chemical, textural, and sensory features of wheat bread, showing better performances compared to the use of quinoa flour. Protein digestibility and quality, and the rate of starch hydrolysis were also nutritional features that markedly improved using quinoa sourdough as an ingredient. This study exploited the potential of quinoa flour through sourdough fermentation. A number of advantages encouraged the manufacture of novel and healthy leavened baked goods. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Bioassessment of heavy metal toxicity and enhancement of heavy metal removal by sulfate-reducing bacteria in the presence of zero valent iron.

    Science.gov (United States)

    Guo, Jing; Kang, Yong; Feng, Ying

    2017-12-01

    A simple and valid toxicity evaluation of Zn 2+ , Mn 2+ and Cr 6+ on sulfate-reducing bacteria (SRB) and heavy metal removal were investigated using the SRB system and SRB+Fe 0 system. The heavy metal toxicity coefficient (β) and the heavy metal concentration resulting in 50% inhibition of sulfate reduction (I) from a modeling process were proposed to evaluate the heavy metal toxicity and nonlinear regression was applied to search for evaluation indices β and I. The heavy metal toxicity order was Cr 6+  > Mn 2+  > Zn 2+ . Compared with the SRB system, the SRB+Fe 0 system exhibited a better capability for sulfate reduction and heavy metal removal. The heavy metal removal was above 99% in the SRB+Fe 0 system, except for Mn 2+ . The energy-dispersive spectroscopy (EDS) analysis showed that the precipitates were removed primarily as sulfide for Zn 2+ and hydroxide for Mn 2+ and Cr 6+ .The method of evaluating the heavy metal toxicity on SRB was of great significance to understand the fundamentals of the heavy metal toxicity and inhibition effects on the microorganism and regulate the process of microbial sulfate reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Switching between Magnetotactic and Aerotactic Displacement Controls to Enhance the Efficacy of MC-1 Magneto-Aerotactic Bacteria as Cancer-Fighting Nanorobots

    Directory of Open Access Journals (Sweden)

    Sylvain Martel

    2016-05-01

    Full Text Available The delivery of drug molecules to tumor hypoxic areas could yield optimal therapeutic outcomes. This suggests that effective cancer-fighting micro- or nanorobots would require more integrated functionalities than just the development of directional propelling constructs which have so far been the main general emphasis in medical micro- and nanorobotic research. Development of artificial agents that would be most effective in targeting hypoxic regions may prove to be a very challenging task considering present technological constraints. Self-propelled, sensory-based and directionally-controlled agents in the form of Magnetotactic Bacteria (MTB of the MC-1 strain have been investigated as effective therapeutic nanorobots in cancer therapy. Following computer-based magnetotactic guidance to reach the tumor area, the microaerophilic response of drug-loaded MC-1 cells could be exploited in the tumoral interstitial fluid microenvironments. Accordingly, their swimming paths would be guided by a decreasing oxygen concentration towards the hypoxic regions. However, the implementation of such a targeting strategy calls for a method to switch from a computer-assisted magnetotactic displacement control to an autonomous aerotactic displacement control. In this way, the MC-1 cells will navigate to tumoral regions and, once there, target hypoxic areas through their microaerophilic behavior. Here we show not only how the magnitude of the magnetic field can be used for this purpose but how the findings could help determine the specifications of a future compatible interventional platform within known technological and medical constraints.

  4. Effect of plant growth-promoting bacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) inoculation on oats in saline-alkali soil contaminated by petroleum to enhance phytoremediation.

    Science.gov (United States)

    Xun, Feifei; Xie, Baoming; Liu, Shasha; Guo, Changhong

    2015-01-01

    To investigate the effect of plant growth-promoting bacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on phytoremediation in saline-alkali soil contaminated by petroleum, saline-alkali soil samples were artificially mixed with different amount of oil, 5 and 10 g/kg, respectively. Pot experiments with oat plants (Avena sativa) were conducted under greenhouse condition for 60 days. Plant biomass, physiological parameters in leaves, soil enzymes, and degradation rate of total petroleum hydrocarbon were measured. The result demonstrated that petroleum inhibited the growth of the plant; however, inoculation with PGPR in combination with AMF resulted in an increase in dry weight and stem height compared with noninoculated controls. Petroleum stress increased the accumulation of malondialdehyde (MDA) and free proline and the activities of the antioxidant enzyme such as superoxide dismutase, catalase, and peroxidase. Application of PGPR and AMF augmented the activities of three enzymes compared to their respective uninoculated controls, but decreased the MDA and free proline contents, indicating that PGPR and AMF could make the plants more tolerant to harmful hydrocarbon contaminants. It also improved the soil quality by increasing the activities of soil enzyme such as urease, sucrase, and dehydrogenase. In addition, the degradation rate of total petroleum hydrocarbon during treatment with PGPR and AMF in moderately contaminated soil reached a maximum of 49.73%. Therefore, we concluded the plants treated with a combination of PGPR and AMF had a high potential to contribute to remediation of saline-alkali soil contaminated with petroleum.

  5. Functional bacteria and process metabolism of the Denitrifying Sulfur conversion-associated Enhanced Biological Phosphorus Removal (DS-EBPR) system: An investigation by operating the system from deterioration to restoration.

    Science.gov (United States)

    Guo, Gang; Wu, Di; Hao, Tianwei; Mackey, Hamish Robert; Wei, Li; Wang, Haiguang; Chen, Guanghao

    2016-05-15

    A sulfur conversion-associated Enhanced Biological Phosphorus (P) Removal (EBPR) system is being developed to cater for the increasing needs to treat saline/brackish wastewater resulting from seawater intrusion into groundwater and sewers and frequent use of sulfate coagulants during drinking water treatment, as well as to meet the demand for eutrophication control in warm climate regions. However, the major functional bacteria and metabolism in this emerging biological nutrient removal system are still poorly understood. This study was thus designed to explore the functional microbes and metabolism in this new EBPR system by manipulating the deterioration, failure and restoration of a lab-scale system. This was achieved by changing the mixed liquor suspended solids (MLSS) concentration to monitor and evaluate the relationships among sulfur conversion (including sulfate reduction and sulfate production), P removal, variation in microbial community structures, and stoichiometric parameters. The results show that the stable Denitrifying Sulfur conversion-associated EBPR (DS-EBPR) system was enriched by sulfate-reducing bacteria (SRB) and sulfide-oxidizing bacteria (SOB). These bacteria synergistically participated in this new EBPR process, thereby inducing an appropriate level of sulfur conversion crucial for achieving a stable DS-EBPR performance, i.e. maintaining sulfur conversion intensity at 15-40 mg S/L, corresponding to an optimal sludge concentration of 6.5 g/L. This range of sulfur conversion favors microbial community competition and various energy flows from internal polymers (i.e. polysulfide or elemental sulfur (poly-S(2-)/S(0)) and poly-β-hydroxyalkanoates (PHA)) for P removal. If this range was exceeded, the system might deteriorate or even fail due to enrichment of glycogen-accumulating organisms (GAOs). Four methods of restoring the failed system were investigated: increasing the sludge concentration, lowering the salinity or doubling the COD

  6. Bleach vs. Bacteria

    Science.gov (United States)

    ... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

  7. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  8. Enhanced Production of Gypenoside LXXV Using a Novel Ginsenoside-Transforming β-Glucosidase from Ginseng-Cultivating Soil Bacteria and Its Anti-Cancer Property

    Directory of Open Access Journals (Sweden)

    Chang-Hao Cui

    2017-05-01

    Full Text Available Minor ginsenosides, such as compound K, Rg3(S, which can be produced by deglycosylation of ginsenosides Rb1, showed strong anti-cancer effects. However, the anticancer effects of gypenoside LXXV, which is one of the deglycosylated shapes of ginsenoside Rb1, is still unknown due to the rarity of its content in plants. Here, we cloned and characterized a novel ginsenoside-transforming β-glucosidase (BglG167b derived from Microbacterium sp. Gsoil 167 which can efficiently hydrolyze gypenoside XVII into gypenoside LXXV, and applied it to the production of gypenoside LXXV at the gram-scale with high specificity. In addition, the anti-cancer activity of gypenoside LXXV was investigated against three cancer cell lines (HeLa, B16, and MDA-MB231 in vitro. Gypenoside LXXV significantly reduced cell viability, displaying an enhanced anti-cancer effect compared to gypenoside XVII and Rb1. Taken together, this enzymatic method would be useful in the preparation of gypenoside LXXV for the functional food and pharmaceutical industries.

  9. Enhancement of anaerobic acidogenesis by integrating an electrochemical system into an acidogenic reactor: effect of hydraulic retention times (HRT) and role of bacteria and acidophilic methanogenic Archaea.

    Science.gov (United States)

    Zhang, Jingxin; Zhang, Yaobin; Quan, Xie; Chen, Shuo

    2015-03-01

    In this study, an acidogenic reactor packed with a pair of Fe-carbon electrodes (R1) was developed to enhance anaerobic acidogenesis of organic wastewater at short hydraulic retention times. The results indicated that the acidogenic efficiency was improved by settling a bio-electrochemical system. When hydraulic retention times decreased from 12 to 3h, R1 showed 18.9% more chemical oxygen demand removal and 13.8% more acidification efficiency. After cutting off the voltage of R1, the COD removal decreased by about 5%. Coupling of Fe(2+) leaching and electric field accelerated the hydrolysis of polysaccharide, relieving its accumulation in the sludge phase. Several acidophilic methanogenic Archaea such as Methanosarcina sp. were enriched in R1, which was favorable for consuming organic acids and preventing excessive pH decline. Thus, the developed acidogenic reactor with Fe-carbon electrodes is expected to be potentially effective and useful for wastewater treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Hyphae colonizing bacteria associated with Penicillium bilaii

    DEFF Research Database (Denmark)

    Ghodsalavi, Behnoushsadat

    shown that mycorrhizal helper bacteria presenting in mycorrhizal fungi could stimulate fungal growth, promote establishment of root-fungus symbiosis and enhance plant production. But it is unknown if the comparable relationship exist between the non-mycorrhizal fungus P. bilaii and its hyphae associated...... bacteria. In the current PhD thesis, we assumed that hyphae-associated microbiome of P. bilaii might harbor helper bacteria with ability to improve fungal growth and P solubilization performance. Therefore, we aimed to isolate bacteria associated with the P. bilaii hyphae and identify the fungal growth...... stimulating bacteria with the perspective of promoting efficiency of Jumpstart in soil – plant system. For this purpose, most of the work within the current project was carried out by development of suitable model systems by mimicking the natural soil habitat to reach to the reliable performance in soil...

  11. The Effect of Bacteria Penetration on Chalk Permeability

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Shapiro, Alexander; Nielsen, Sidsel Marie

    number of B. licheniformis was detected on the effluent compared with P. putida. However, in the experiment with B. licheniformis mainly spores were detected in the effluent. The core permeability decreased rapidly during injection of bacteria and a starvation period of 12 days did not allow......Bacteria selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery. Bacteria can plug the water-bearing zones of a reservoir, thus altering the flow paths and improving sweep efficiency. It is known that the bacteria can penetrate deeply...... into reservoirs, however, a complete understanding of the penetration behavior of bacteria is lacking, especially in chalk formations where the pore throat sizes are almost comparable with the sizes of bacteria vegetative cells. This study investigates the penetration of bacteria into chalk. Two bacteria types...

  12. Genomics of Probiotic Bacteria

    Science.gov (United States)

    O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

    Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

  13. How honey kills bacteria

    NARCIS (Netherlands)

    Kwakman, Paulus H. S.; te Velde, Anje A.; de Boer, Leonie; Speijer, Dave; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

    2010-01-01

    With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria

  14. Bacteria classification using Cyranose 320 electronic nose

    Directory of Open Access Journals (Sweden)

    Gardner Julian W

    2002-10-01

    Full Text Available Abstract Background An electronic nose (e-nose, the Cyrano Sciences' Cyranose 320, comprising an array of thirty-two polymer carbon black composite sensors has been used to identify six species of bacteria responsible for eye infections when present at a range of concentrations in saline solutions. Readings were taken from the headspace of the samples by manually introducing the portable e-nose system into a sterile glass containing a fixed volume of bacteria in suspension. Gathered data were a very complex mixture of different chemical compounds. Method Linear Principal Component Analysis (PCA method was able to classify four classes of bacteria out of six classes though in reality other two classes were not better evident from PCA analysis and we got 74% classification accuracy from PCA. An innovative data clustering approach was investigated for these bacteria data by combining the 3-dimensional scatter plot, Fuzzy C Means (FCM and Self Organizing Map (SOM network. Using these three data clustering algorithms simultaneously better 'classification' of six eye bacteria classes were represented. Then three supervised classifiers, namely Multi Layer Perceptron (MLP, Probabilistic Neural network (PNN and Radial basis function network (RBF, were used to classify the six bacteria classes. Results A [6 × 1] SOM network gave 96% accuracy for bacteria classification which was best accuracy. A comparative evaluation of the classifiers was conducted for this application. The best results suggest that we are able to predict six classes of bacteria with up to 98% accuracy with the application of the RBF network. Conclusion This type of bacteria data analysis and feature extraction is very difficult. But we can conclude that this combined use of three nonlinear methods can solve the feature extraction problem with very complex data and enhance the performance of Cyranose 320.

  15. Antibiotics from predatory bacteria

    Directory of Open Access Journals (Sweden)

    Juliane Korp

    2016-03-01

    Full Text Available Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism.

  16. Hydrocarbon degradation potentials of bacteria isolated from spent ...

    African Journals Online (AJOL)

    Hydrocarbon degradation potentials of bacteria isolated from spent lubricating oil contaminated soil. ... This study has shown that resident bacteria strains in lubricating oil contaminated soils have potential application in the bioremediation of oil polluted sites and enhance the possibility of developing models and strategies ...

  17. Extracellular communication in bacteria

    DEFF Research Database (Denmark)

    Chhabra, S.R.; Philipp, B.; Eberl, L.

    2005-01-01

    molecules, in different Gram-positive and Gram-negative bacteria they control pathogenicity, secondary metabolite production, biofilm differentiation, DNA transfer and bioluminescence. The development of biosensors for the detection of these signal molecules has greatly facilitated their subsequent chemical...

  18. Do Bacteria Age?

    Indian Academy of Sciences (India)

    Bacteria are thought to be examples of organisms that do not age. They divide by .... carry genetic material to the next generation through the process of reproduction; they are also .... molecules, and modified proteins. This report revealed that ...

  19. Social Behaviour in Bacteria

    Indian Academy of Sciences (India)

    Administrator

    the recipient. • Social behaviours can be categorized according to the fitness ... is actually the flagella of symbiotic spirochete bacteria that helps it to swim around .... Normal population. Responsive switching. (Environmental stress). Stochastic.

  20. [Darwin and bacteria].

    Science.gov (United States)

    Ledermann D, Walter

    2009-02-01

    As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

  1. Lipopolysaccharides in diazotrophic bacteria

    OpenAIRE

    Serrato, Rodrigo V.

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are...

  2. Lipopolysaccharides in diazotrophic bacteria.

    Science.gov (United States)

    Serrato, Rodrigo V

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.

  3. Extracellular deoxyribonuclease production by periodontal bacteria.

    Science.gov (United States)

    Palmer, L J; Chapple, I L C; Wright, H J; Roberts, A; Cooper, P R

    2012-08-01

    Whilst certain bacteria have long been known to secrete extracellular deoxyribonuclease (DNase), the purpose in microbial physiology was unclear. Recently, however, this enzyme has been demonstrated to confer enhanced virulence, enabling bacteria to evade the host's immune defence of extruded DNA/chromatin filaments, termed neutrophil extracellular traps (NETs). As NETs have recently been identified in infected periodontal tissue, the aim of this study was to screen periodontal bacteria for extracellular DNase activity. To determine whether DNase activity was membrane bound or secreted, 34 periodontal bacteria were cultured in broth and on agar plates. Pelleted bacteria and supernatants from broth cultures were analysed for their ability to degrade DNA, with relative activity levels determined using an agarose gel electrophoresis assay. Following culture on DNA-supplemented agar, expression was determined by the presence of a zone of hydrolysis and DNase activity related to colony size. Twenty-seven bacteria, including red and orange complex members Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Streptococcus constellatus, Campylobacter rectus and Prevotella nigrescens, were observed to express extracellular DNase activity. Differences in DNase activity were noted, however, when bacteria were assayed in different culture states. Analysis of the activity of secreted DNase from bacterial broth cultures confirmed their ability to degrade NETs. The present study demonstrates, for the first time, that DNase activity is a relatively common property of bacteria associated with advanced periodontal disease. Further work is required to determine the importance of this bacterial DNase activity in the pathogenesis of periodontitis. © 2011 John Wiley & Sons A/S.

  4. The fecal bacteria

    Science.gov (United States)

    Sadowsky, Michael J.; Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  5. Mycorrhiza helper bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Deveau, Aurelie [French National Insitute for Agricultural Research (INRA); Labbe, Jessy [ORNL

    2016-10-01

    This chapter focuses on the Mycorrhiza Helper Bacteria (MHB), a generic name given to bacteria which stimulate the formation of mycorrhizal symbiosis. By extension, some bacterial strains that positively impact the functioning of mycorrhizal symbiosis are also called MHB. These bacteria have applicative interests, as they indirectly improve the health and growth of tree seedlings. MHB are not restricted to a specific type of ecosystem, but are rather generalist in the way that they associate with both herbaceous and woody mycorrhizal plants from boreal, temperate, arid and tropical ecosystems. However, understanding the molecular mechanisms and their specificities will help us to know more about the ecology of the MHB. The process of acquisition varies between fungal species; while ectomycorrhizal fungi most probably recurrently acquire them from the environment, the association between bacterial endosymbionts and Glomeromycota probably dates back to very ancient times, and has since been vertically transmitted.

  6. Enhanced antiadhesive properties of chitosan/hyaluronic acid polyelectrolyte multilayers driven by thermal annealing: Low adherence for mammalian cells and selective decrease in adhesion for Gram-positive bacteria.

    Science.gov (United States)

    Muzzio, Nicolás E; Pasquale, Miguel A; Diamanti, Eleftheria; Gregurec, Danijela; Moro, Marta Martinez; Azzaroni, Omar; Moya, Sergio E

    2017-11-01

    The development of antifouling coatings with restricted cell and bacteria adherence is fundamental for many biomedical applications. A strategy for the fabrication of antifouling coatings based on the layer-by-layer assembly and thermal annealing is presented. Polyelectrolyte multilayers (PEMs) assembled from chitosan and hyaluronic acid were thermally annealed in an oven at 37°C for 72h. The effect of annealing on the PEM properties and topography was studied by atomic force microscopy, ζ-potential, circular dichroism and contact angle measurements. Cell adherence on PEMs before and after annealing was evaluated by measuring the cell spreading area and aspect ratio for the A549 epithelial, BHK kidney fibroblast, C2C12 myoblast and MC-3T3-E1 osteoblast cell lines. Chitosan/hyaluronic acid PEMs show a low cell adherence that decreases with the thermal annealing, as observed from the reduction in the average cell spreading area and more rounded cell morphology. The adhesion of S. aureus (Gram-positive) and E. coli (Gram-negative) bacteria strains was quantified by optical microscopy, counting the number of colony-forming units and measuring the light scattering of bacteria suspension after detachment from the PEM surface. A 20% decrease in bacteria adhesion was selectively observed in the S. aureus strain after annealing. The changes in mammalian cell and bacteria adhesion correlate with the changes in topography of the chitosan/hyaluronic PEMs from a rough fibrillar 3D structure to a smoother and planar surface after thermal annealing. Copyright © 2017. Published by Elsevier B.V.

  7. Injecting a liquid bacteria-based repair system to make porous network conrete healed

    NARCIS (Netherlands)

    Sangadji, S.; Wiktor, V.A.C.; Jonkers, H.M.; Schlangen, H.E.J.G.

    2013-01-01

    Bacteria induced calcite precipitation has been proven to be effective in making concrete structure self-healing. In Microlab TU Delft, the concept has been enhanced by developing a liquid bacteria-based concrete repair system. The solution contains calcite precipitating bacteria, nutrients and

  8. Communication among Oral Bacteria

    Science.gov (United States)

    Kolenbrander, Paul E.; Andersen, Roxanna N.; Blehert, David S.; Egland, Paul G.; Foster, Jamie S.; Palmer, Robert J.

    2002-01-01

    Human oral bacteria interact with their environment by attaching to surfaces and establishing mixed-species communities. As each bacterial cell attaches, it forms a new surface to which other cells can adhere. Adherence and community development are spatiotemporal; such order requires communication. The discovery of soluble signals, such as autoinducer-2, that may be exchanged within multispecies communities to convey information between organisms has emerged as a new research direction. Direct-contact signals, such as adhesins and receptors, that elicit changes in gene expression after cell-cell contact and biofilm growth are also an active research area. Considering that the majority of oral bacteria are organized in dense three-dimensional biofilms on teeth, confocal microscopy and fluorescently labeled probes provide valuable approaches for investigating the architecture of these organized communities in situ. Oral biofilms are readily accessible to microbiologists and are excellent model systems for studies of microbial communication. One attractive model system is a saliva-coated flowcell with oral bacterial biofilms growing on saliva as the sole nutrient source; an intergeneric mutualism is discussed. Several oral bacterial species are amenable to genetic manipulation for molecular characterization of communication both among bacteria and between bacteria and the host. A successful search for genes critical for mixed-species community organization will be accomplished only when it is conducted with mixed-species communities. PMID:12209001

  9. PATHOGENICITY OF BIOFILM BACTERIA

    Science.gov (United States)

    There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...

  10. Bacteria-surface interactions.

    Science.gov (United States)

    Tuson, Hannah H; Weibel, Douglas B

    2013-05-14

    The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field.

  11. Antifreeze Proteins of Bacteria

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 12. Antifreeze Proteins of Bacteria. M K Chattopadhyay. General Article Volume 12 Issue 12 December 2007 pp 25-30. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/012/12/0025-0030 ...

  12. Use of thermophilic bacteria for bioremediation of petroleum contaminants

    International Nuclear Information System (INIS)

    Al-Maghrabi, I.M.A.; Bin Aqil, A.O.; Chaalal, O.; Islam, M.R.

    1999-01-01

    Several strains of thermophilic bacteria were isolated from the environment of the United Arab Emirates. These bacteria show extraordinary resistance to heat and have their maximum growth rate around 60--80 C. This article investigates the potential of using these facultative bacteria for both in situ and ex situ bioremediation of petroleum contaminants. In a series of batch experiments, bacterial growth was observed using a computer image analyzer following a recently developed technique. These experiments showed clearly that the growth rate is enhanced in the presence of crude oil. This is coupled with a rapid degradation of the crude oil. These bacteria were found to be ideal for breaking down long-chain organic molecules at a temperature of 40 C, which is the typical ambient temperature of the Persian Gulf region. The same strains of bacteria are also capable of surviving in the presence of the saline environment that can prevail in both sea water and reservoir connate water. This observation prompted further investigation into the applicability of the bacteria in microbial enhanced oil recovery. In the United Arab Emirates, the reservoirs are typically at a temperature of around 85 C. Finally, the performance of the bacteria is tested in a newly developed bioreactor that uses continuous aeration through a transverse slotted pipe. This reactor also uses mixing without damaging the filamentous bacteria. In this process, the mechanisms of bioremediation are identified

  13. In situ growing Bi{sub 2}MoO{sub 6} on g-C{sub 3}N{sub 4} nanosheets with enhanced photocatalytic hydrogen evolution and disinfection of bacteria under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Juan [School of Chemical Engineering, Northwest University, Xi’an, 710069 (China); School of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, Luoyang, 471023 (China); Yin, Yunchao; Liu, Enzhou; Ma, Yongning; Wan, Jun [School of Chemical Engineering, Northwest University, Xi’an, 710069 (China); Fan, Jun, E-mail: fanjun@nwu.edu.cn [School of Chemical Engineering, Northwest University, Xi’an, 710069 (China); Hu, Xiaoyun, E-mail: hxy3275@nwu.edu.cn [School of Physics, Northwest University, Xi’an, 710069 (China)

    2017-01-05

    Graphical abstract: TEM image and schematic diagram of photocatalytic mechanism of Bi{sub 2}MoO{sub 6}/g-C{sub 3}N{sub 4} composite. - Highlights: • BM/CNNs heterojunctions were obtained by an in situ solvothermal method. • 2D CNNs are superior to CN as photocatalysts and supporting materials. • The photocatalytic hydrogen evolution of BM/CNNs has been first studied. • The photocatalytic disinfection of bacteria by BM/CNNs has been first studied. • The photocatalytic mechanism of BM/CNNs heterojunction was described. - Abstract: Bi{sub 2}MoO{sub 6}/g-C{sub 3}N{sub 4} heterojunctions were fabricated by an in situ solvothermal method using g-C{sub 3}N{sub 4} nanosheets. The photocatalytic activities of as-prepared samples were evaluated by hydrogen evolution from water splitting and disinfection of bacteria under visible light irradiation. The results indicate that exfoliating bulk g-C{sub 3}N{sub 4} to g-C{sub 3}N{sub 4} nanosheets greatly enlarges the specific surface area and shortens the diffusion distance for photogenerated charges, which could not only promote the photocatalytic performance but also benefit the sufficient interaction with Bi{sub 2}MoO{sub 6}. Furthermore, intimate contact of Bi{sub 2}MoO{sub 6} (BM) and g-C{sub 3}N{sub 4} nanosheets (CNNs) in the BM/CNNs composites facilitates the transfer and separation of photogenetrated electron-hole pairs. 20%-BM/CNNs heterojunction exhibits the optimal photocatalytic hydrogen evolution as well as photocatalytic disinfection of bacteria. Furthermore, h{sup +} was demonstrated as the dominant reactive species which could make the bacteria cells inactivated in the photocatalytic disinfection process. This study extends new chance of g-C{sub 3}N{sub 4}-based photocatalysts to the growing demand of clean new energy and drinking water.

  14. In situ growing Bi_2MoO_6 on g-C_3N_4 nanosheets with enhanced photocatalytic hydrogen evolution and disinfection of bacteria under visible light irradiation

    International Nuclear Information System (INIS)

    Li, Juan; Yin, Yunchao; Liu, Enzhou; Ma, Yongning; Wan, Jun; Fan, Jun; Hu, Xiaoyun

    2017-01-01

    Graphical abstract: TEM image and schematic diagram of photocatalytic mechanism of Bi_2MoO_6/g-C_3N_4 composite. - Highlights: • BM/CNNs heterojunctions were obtained by an in situ solvothermal method. • 2D CNNs are superior to CN as photocatalysts and supporting materials. • The photocatalytic hydrogen evolution of BM/CNNs has been first studied. • The photocatalytic disinfection of bacteria by BM/CNNs has been first studied. • The photocatalytic mechanism of BM/CNNs heterojunction was described. - Abstract: Bi_2MoO_6/g-C_3N_4 heterojunctions were fabricated by an in situ solvothermal method using g-C_3N_4 nanosheets. The photocatalytic activities of as-prepared samples were evaluated by hydrogen evolution from water splitting and disinfection of bacteria under visible light irradiation. The results indicate that exfoliating bulk g-C_3N_4 to g-C_3N_4 nanosheets greatly enlarges the specific surface area and shortens the diffusion distance for photogenerated charges, which could not only promote the photocatalytic performance but also benefit the sufficient interaction with Bi_2MoO_6. Furthermore, intimate contact of Bi_2MoO_6 (BM) and g-C_3N_4 nanosheets (CNNs) in the BM/CNNs composites facilitates the transfer and separation of photogenetrated electron-hole pairs. 20%-BM/CNNs heterojunction exhibits the optimal photocatalytic hydrogen evolution as well as photocatalytic disinfection of bacteria. Furthermore, h"+ was demonstrated as the dominant reactive species which could make the bacteria cells inactivated in the photocatalytic disinfection process. This study extends new chance of g-C_3N_4-based photocatalysts to the growing demand of clean new energy and drinking water.

  15. The friendly bacteria within us Commensal bacteria of the intestine ...

    Indian Academy of Sciences (India)

    Balance of bacterial species in the gut · Immunosensory detection of intestinal bacteria · Pathogenic bacteria release interleukin-8 from HT-29 cells · Lactobacillus GG prevents the IL-8 release in response to pathogens · Effect of probiotic bacteria on chemokine response of epithelia to pathogens · PCR array studies in colon ...

  16. Manufacture of Probiotic Bacteria

    Science.gov (United States)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  17. Pepsin homologues in bacteria

    Directory of Open Access Journals (Sweden)

    Bateman Alex

    2009-09-01

    Full Text Available Abstract Background Peptidase family A1, to which pepsin belongs, had been assumed to be restricted to eukaryotes. The tertiary structure of pepsin shows two lobes with similar folds and it has been suggested that the gene has arisen from an ancient duplication and fusion event. The only sequence similarity between the lobes is restricted to the motif around the active site aspartate and a hydrophobic-hydrophobic-Gly motif. Together, these contribute to an essential structural feature known as a psi-loop. There is one such psi-loop in each lobe, and so each lobe presents an active Asp. The human immunodeficiency virus peptidase, retropepsin, from peptidase family A2 also has a similar fold but consists of one lobe only and has to dimerize to be active. All known members of family A1 show the bilobed structure, but it is unclear if the ancestor of family A1 was similar to an A2 peptidase, or if the ancestral retropepsin was derived from a half-pepsin gene. The presence of a pepsin homologue in a prokaryote might give insights into the evolution of the pepsin family. Results Homologues of the aspartic peptidase pepsin have been found in the completed genomic sequences from seven species of bacteria. The bacterial homologues, unlike those from eukaryotes, do not possess signal peptides, and would therefore be intracellular acting at neutral pH. The bacterial homologues have Thr218 replaced by Asp, a change which in renin has been shown to confer activity at neutral pH. No pepsin homologues could be detected in any archaean genome. Conclusion The peptidase family A1 is found in some species of bacteria as well as eukaryotes. The bacterial homologues fall into two groups, one from oceanic bacteria and one from plant symbionts. The bacterial homologues are all predicted to be intracellular proteins, unlike the eukaryotic enzymes. The bacterial homologues are bilobed like pepsin, implying that if no horizontal gene transfer has occurred the duplication

  18. Overexpression of O-polysaccharide chain length regulators in Gram-negative bacteria using the Wzx-/Wzy-dependent pathway enhances production of defined modal length O-polysaccharide polymers for use as haptens in glycoconjugate vaccines.

    Science.gov (United States)

    Hegerle, N; Bose, J; Ramachandran, G; Galen, J E; Levine, M M; Simon, R; Tennant, S M

    2018-03-30

    O-polysaccharide (OPS) molecules are protective antigens for several bacterial pathogens, and have broad utility as components of glycoconjugate vaccines. Variability in the OPS chain length is one obstacle towards further development of these vaccines. Introduction of sizing steps during purification of OPS molecules of suboptimal or of mixed lengths introduces additional costs and complexity while decreasing the final yield. The overall goal of this study was to demonstrate the utility of engineering Gram-negative bacteria to produce homogenous O-polysaccharide populations that can be used as the basis of carbohydrate vaccines by overexpressing O-polysaccharide chain length regulators of the Wzx-/Wzy-dependent pathway. The O-polysaccharide chain length regulators wzzB and fepE from Salmonella Typhimurium I77 and wzz2 from Pseudomonas aeruginosa PAO1 were cloned and expressed in the homologous organism or in other Gram-negative bacteria. Overexpression of these Wzz proteins in the homologous organism significantly increased the proportion of long or very long chain O-polysaccharides. The same observation was made when wzzB was overexpressed in Salmonella Paratyphi A and Shigella flexneri, and wzz2 was overexpressed in two other strains of P. aeruginosa. Overexpression of Wzz proteins in Gram-negative bacteria using the Wzx/Wzy-dependant pathway for lipopolysaccharide synthesis provides a genetic method to increase the production of an O-polysaccharide population of a defined size. The methods presented herein represent a cost-effective and improved strategy for isolating preferred OPS vaccine haptens, and could facilitate the further use of O-polysaccharides in glycoconjugate vaccine development. © 2018 The Society for Applied Microbiology.

  19. Functional amyloids in bacteria.

    Science.gov (United States)

    Romero, Diego; Kolter, Roberto

    2014-06-01

    The term amyloidosis is used to refer to a family of pathologies altering the homeostasis of human organs. Despite having a name that alludes to starch content, the amyloid accumulations are made up of proteins that polymerize as long and rigid fibers. Amyloid proteins vary widely with respect to their amino acid sequences but they share similarities in their quaternary structure; the amyloid fibers are enriched in β-sheets arranged perpendicular to the axis of the fiber. This structural feature provides great robustness, remarkable stability, and insolubility. In addition, amyloid proteins specifically stain with certain dyes such as Congo red and thioflavin-T. The aggregation into amyloid fibers, however, it is not restricted to pathogenic processes, rather it seems to be widely distributed among proteins and polypeptides. Amyloid fibers are present in insects, fungi and bacteria, and they are important in maintaining the homeostasis of the organism. Such findings have motivated the use of the term "functional amyloid" to differentiate these amyloid proteins from their toxic siblings. This review focuses on systems that have evolved in bacteria that control the expression and assembly of amyloid proteins on cell surfaces, such that the robustness of amyloid proteins are used towards a beneficial end. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  20. Gut microbiota of Tenebrio molitor and their response to environmental change.

    Science.gov (United States)

    Jung, Jaejoon; Heo, Aram; Park, Yong Woo; Kim, Ye Ji; Koh, Hyelim; Park, Woojun

    2014-07-01

    A bacterial community analysis of the gut of Tenebrio molitor larvae was performed using pyrosequencing of the 16S rRNA gene. A predominance of genus Spiroplasma species in phylum Tenericutes was observed in the gut samples, but there was variation found in the community composition between T. molitor individuals. The gut bacteria community structure was not significantly affected by the presence of antibiotics or by the exposure of T. molitor larvae to a highly diverse soil bacteria community. A negative relationship was identified between bacterial diversity and ampicillin concentration; however, no negative relationship was identified with the addition of kanamycin. Ampicillin treatment resulted in a reduction in the bacterial community size, estimated using the 16S rRNA gene copy number. A detailed phylogenetic analysis indicated that the Spiroplasma-associated sequences originating from the T. molitor larvae were distinct from previously identified Spiroplasma type species, implying the presence of novel Spiroplasma species. Some Spiroplasma species are known to be insect pathogens; however, the T. molitor larvae did not experience any harmful effects arising from the presence of Spiroplasma species, indicating that Spiroplasma in the gut of T. molitor larvae do not act as a pathogen to the host. A comparison with the bacterial communities found in other insects (Apis and Solenopsis) showed that the Spiroplasma species found in this study were specific to T. molitor.

  1. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  2. Immunomodulatory properties of probiotic bacteria

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen

    2007-01-01

    Certain lactic acid bacteria (LAB) are part of the commensal intestinal flora and considered beneficial for health, as they compete with pathogens for adhesion sites in the intestine and ferment otherwise indigestible compounds. Another important property of these so-called probiotic bacteria...... with bacteria, and the cytokine pattern induced by specific bacteria resembled the pattern induced in MoDC, except for TNF-alpha and IL-6, which were induced in response to different bacteria in blood DC/monocytes and monocyte-derived DC. Autologous NK cells produced IFN-gamma when cultured with blood DC......, monocytes and monocyte-derived DC and IL-12-inducing bacteria, whereas only DC induced IFN-gamma production in allogeneic T cells. In vitro-generated DC is a commonly used model of tissue DC, but they differ in certain aspects from intestinal DC, which are in direct contact with the intestinal microbiota...

  3. Radiation-resistant asporogenic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yano, K [Tokyo Univ. (Japan). Faculty of Agriculture

    1975-09-01

    This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned.

  4. Radiation-resistant asporogenic bacteria

    International Nuclear Information System (INIS)

    Yano, Keiji

    1975-01-01

    This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned. (Tsukamoto, Y.)

  5. Bacteria transport through porous media. Annual report, December 31, 1984

    Energy Technology Data Exchange (ETDEWEB)

    Yen, T.F.

    1986-09-01

    The following five chapters in this report have been processed separately for inclusion in the Energy Data Base: (1) theoretical model of convective diffusion of motile and non-motile bacteria toward solid surfaces; (2) interfacial electrochemistry of oxide surfaces in oil-bearing sands and sandstones; (3) effects of sodium pyrophosphate additive on the ''huff and puff''/nutrient flooding MEOR process; (4) interaction of Escherichia coli B, B/4, and bacteriophage T4D with Berea sandstone rock in relation to enhanced oil recovery; and (5) transport of bacteria in porous media and its significance in microbial enhanced oil recovery.

  6. Acoustofluidic bacteria separation

    International Nuclear Information System (INIS)

    Li, Sixing; Huang, Tony Jun; Ma, Fen; Zeng, Xiangqun; Bachman, Hunter; Cameron, Craig E

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device. (paper)

  7. Acoustofluidic bacteria separation

    Science.gov (United States)

    Li, Sixing; Ma, Fen; Bachman, Hunter; Cameron, Craig E.; Zeng, Xiangqun; Huang, Tony Jun

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device.

  8. Bacteria, phages and septicemia.

    Directory of Open Access Journals (Sweden)

    Ausra Gaidelyte

    Full Text Available The use of phages is an attractive option to battle antibiotic resistant bacteria in certain bacterial infections, but the role of phage ecology in bacterial infections is obscure. Here we surveyed the phage ecology in septicemia, the most severe type of bacterial infection. We observed that the majority of the bacterial isolates from septicemia patients spontaneously secreted phages active against other isolates of the same bacterial strain, but not to the strain causing the disease. Such phages were also detected in the initial blood cultures, indicating that phages are circulating in the blood at the onset of sepsis. The fact that most of the septicemic bacterial isolates carry functional prophages suggests an active role of phages in bacterial infections. Apparently, prophages present in sepsis-causing bacterial clones play a role in clonal selection during bacterial invasion.

  9. Bacteria-Mineral Interactions on the Surfaces of Metal-Resistant Bacteria

    International Nuclear Information System (INIS)

    Malkin, A.J.

    2010-01-01

    The extraordinary ability of indigenous microorganisms, like metal-resistant bacteria, for biotransformation of toxic compounds is of considerable interest for the emerging area of environmental bioremediation. However, the underlying mechanisms by which metal-resistant bacteria transform toxic compounds are currently unknown and await elucidation. The project's objective was to study stress-induced responses of metal-resistant bacteria to environmental changes and chemical stimulants. This project involved a multi-institutional collaboration of our LLNL group with the group of Dr. H.-Y. Holman (Lawrence Berkeley National Laboratory). In this project, we have utilized metal-resistant bacteria Arthrobacter oxydans as a model bacterial system. We have utilized atomic force microscopy (AFM) to visualize for the first time at the nanometer scale formation of stress-induced structures on bacterial surfaces in response to Cr (VI) exposure. We have demonstrated that structure, assembly, and composition of these stress-induced structures are dependent on Cr (VI) concentrations. Our AFM observations of the appearance and development of stress-induced layers on the surfaces of Arthrobacter oxydans bacteria exposed to Cr (VI) were confirmed by Dr. Holman's biochemical, electron microscopy, and synchrotron infrared spectromicroscopy studies. In general, in vitro imaging of live microbial and cellular systems represents one of the most challenging issues in application of AFM. Various approaches for immobilization of bacteria on the substrate for in vitro imaging were tested in this project. Imaging of live bacteria was achieved, however further optimization of experimental methods are needed for high-resolution visualization of the cellular environmental structural dynamics by AFM. This project enhanced the current insight into molecular architecture, structural and environmental variability of bacterial systems. The project partially funded research for two book chapters (1

  10. Enhancing flora balance in the gastrointestinal tract of mice by lactic acid bacteria from Chinese sourdough and enzyme activities indicative of metabolism of protein, fat, and carbohydrate by the flora.

    Science.gov (United States)

    Yang, Dong; Yu, Xiaomin; Wu, Yaoping; Chen, Xingxing; Wei, Hua; Shah, Nagendra P; Xu, Feng

    2016-10-01

    In this study, we investigated the effect of administration of 5 strains of lactic acid bacteria (LAB) isolated from traditional Chinese sourdough on the flora balance of gastrointestinal tract of mice. We specifically measured Enterococcus, Enterobacter, Bacteroides, and Lactobacillus by plate count and real-time PCR methods, and α-glucosidase, lactate dehydrogenase, esterase, and aminopeptidase activities as indicative of metabolism of sugar, fat, and protein from LAB isolated from feces of mice in vitro. The results showed that administration of Lactobacillus acidophilus LAC0201 and Lactobacillus fermentum LFE0302 lowered the uricacid index of serum. Lactobacillus acidophilus LAC0201, L. fermentum LFE0302, as well as Lactobacillus curvatus LCU0401 administration resulted in a reduction in the opportunistic pathogens (i.e., Enterococcus and Enterobacter), meanwhile, administration of L. fermentum LFE0302 and Lactobacillus sp. ULA0104 resulted in an increase in the counts of Lactobacillus. Lactobacillus fermentum LFE0302 administration increased starch digestion of intestinal flora after 4wk of feeding and also resulted in increased α-glucosidase activity in the intestinal flora after 3wk of feeding. We found a similar trend in esterase activity after administration of L. acidophilus LAC0201 for 3wk. Hence, our study suggested that LAB from Chinese sourdough might be used as potential probiotics to strengthen the flora balance in gastrointestinal tract and positively change the metabolism of nutrients through bacterial enzyme activities. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  11. CRISPR-Cas Technologies and Applications in Food Bacteria.

    Science.gov (United States)

    Stout, Emily; Klaenhammer, Todd; Barrangou, Rodolphe

    2017-02-28

    Clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) proteins form adaptive immune systems that occur in many bacteria and most archaea. In addition to protecting bacteria from phages and other invasive mobile genetic elements, CRISPR-Cas molecular machines can be repurposed as tool kits for applications relevant to the food industry. A primary concern of the food industry has long been the proper management of food-related bacteria, with a focus on both enhancing the outcomes of beneficial microorganisms such as starter cultures and probiotics and limiting the presence of detrimental organisms such as pathogens and spoilage microorganisms. This review introduces CRISPR-Cas as a novel set of technologies to manage food bacteria and offers insights into CRISPR-Cas biology. It primarily focuses on the applications of CRISPR-Cas systems and tools in starter cultures and probiotics, encompassing strain-typing, phage resistance, plasmid vaccination, genome editing, and antimicrobial activity.

  12. Elective culture of bacteria used in bioleaching on pyrrhotite

    Institute of Scientific and Technical Information of China (English)

    邱冠周; 覃文庆; 蓝卓越; 黎维中

    2003-01-01

    Elective culture of bacteria on pyrrhotite was researched, and the selected bacteria were tested on bi-oleaching of marmatite and zinc sulfide ore. The results show that the microorganism cultured on pyrrhotite with va-rious S/Fe ratios is a mixed culture of thiobacillus ferrooxidans and thiobacillus thiooxidans, of which the integral ac-tivity and the oxidation capability of Fe2+ and S are enhanced. With the high Fe and low S content of pyrrhotite, the oxida-tion capacity of ferrous ion is improved; on the contrary, the oxidation capacity of sulfur is advanced. The bioleaching ca-pacity of bacteria cultured on marmatite is better than that of the bacteria cultivated by conventional methods.

  13. Ecophysiology of the Anammox Bacteria

    NARCIS (Netherlands)

    Kartal, M.B.

    2008-01-01

    Anaerobic ammonium oxidizing (anammox) bacteria oxidize ammonium to dinitrogen gas with nitrite as the electron acceptor. These bacteria are the key players in the global nitrogen cycle, responsible for the most of nitrogen production in natural ecosystems. The anammox process is also a

  14. Money and transmission of bacteria.

    NARCIS (Netherlands)

    Gedik, H.; Voss, T.A.; Voss, A.

    2013-01-01

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria

  15. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

  16. METHODS FOR DETECTING BACTERIA USING POLYMER MATERIALS

    NARCIS (Netherlands)

    Van Grinsven Bart Robert, Nicolaas; Cleij, Thomas

    2017-01-01

    A method for characterizing bacteria includes passing a liquid containing an analyte comprising a first bacteria and a second bacteria over and in contact with a polymer material on a substrate. The polymer material is formulated to bind to the first bacteria, and the first bacteria binds to the

  17. Facilitation of phosphorus uptake in maize plants by mycorrhizosphere bacteria

    DEFF Research Database (Denmark)

    Battini, Fabio; Grønlund, Mette; Agnolucci, Monica

    2017-01-01

    availability of soil P. This study investigated whether biofertilizers and bioenhancers, such as arbuscular mycorrhizal fungi (AMF) and their associated bacteria could enhance growth and P uptake in maize. Plants were grown with or without mycorrhizas in compartmented pots with radioactive P tracers and were...

  18. Effects of rhizobia and plant growth promoting bacteria inoculation ...

    African Journals Online (AJOL)

    Plant growth promoting rhizobacteria (PGPR) stimulate plant growth by producing phytohormone which enhances the growth and physiological activities of the host plant. Recently, legume bacteria (Rhizobium spp.) have been considered as a PGPR for legume as well as non-legumes and have the potential for growth ...

  19. Beer spoilage bacteria and hop resistance

    NARCIS (Netherlands)

    Sakamoto, K; Konings, WN

    2003-01-01

    For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and

  20. Electron transport chains of lactic acid bacteria

    NARCIS (Netherlands)

    Brooijmans, R.J.W.

    2008-01-01

    Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic

  1. Gut Bacteria Affect Immunotherapy Response

    Science.gov (United States)

    Three new studies have identified intestinal bacteria that appear to influence the response to checkpoint inhibitors. This Cancer Currents blog post explains how the researchers think their findings could be used to improve patients’ responses to these immunotherapy drugs.

  2. hydroxyalkanoate (PHAs) producing bacteria isolated

    African Journals Online (AJOL)

    SERVER

    2007-07-04

    Jul 4, 2007 ... ium (MSM), having inhibitors for Gram positive bacteria and fungi and a mixed ... Two techniques were used for detecting the presence of polymer: staining ... was saline solution at 600 nm wavelength on VARIAN DSM 100.

  3. Reactivity of the Bacteria-Water Interface: Linking Nutrient Availability to Bacteria-Metal Interactions

    Science.gov (United States)

    Fowle, D. A.; Daughney, C. J.; Riley, J. L.

    2002-12-01

    Identifying and quantifying the controls on metal mobilities in geologic systems is critical in order to understand processes such as global element cycling, metal transport in near-surface water-rock systems, sedimentary diagenesis, and mineral formation. Bacteria are ubiquitous in near-surface water-rock systems, and numerous laboratory and field studies have demonstrated that bacteria can facilitate the formation and dissolution of minerals, and enhance or inhibit contaminant transport. However, despite the growing evidence that bacteria play a key role in many geologic processes in low temperature systems, our understanding of the influence of the local nutrient dynamics of the system of interest on bacteria-metal interactions is limited. Here we present data demonstrating the effectiveness of coupling laboratory experiments with geochemical modeling to isolate the effect of nutrient availability on bacterially mediated proton and metal adsorption reactions. Experimental studies of metal-bacteria interactions were conducted in batch reactors as a function of pH, and solid-solute interactions after growth in a variety of defined and undefined media. Media nutrient composition (C,N,P) was quantified before and after harvesting the cells. Surface complexation models (SCM) for the adsorption reactions were developed by combining sorption data with the results of acid-base titrations, and in some cases zeta potential titrations of the bacterial surface. Our results indicate a clear change in both buffering potential and metal binding capacity of the cell walls of Bacillus subtilis as a function of initial media conditions. Combining current studies with our past studies on the effects of growth phase and others work on temperature dependence on metal adsorption we hope to develop a holistic surface complexation model for quantifying bacterial effects on metal mass transfer in many geologic systems.

  4. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.

    2006-01-01

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The....... The TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  5. Anaerobic bacteria that dechlorinate perchloroethene.

    Science.gov (United States)

    Fathepure, B Z; Nengu, J P; Boyd, S A

    1987-01-01

    In this study, we identified specific cultures of anaerobic bacteria that dechlorinate perchlorethene (PCE). The bacteria that significantly dechlorinated PCE were strain DCB-1, an obligate anaerobe previously shown to dechlorinate chlorobenzoate, and two strains of Methanosarcina. The rate of PCE dechlorination by DCB-1 compared favorably with reported rates of trichloroethene bio-oxidation by methanotrophs. Even higher PCE dechlorination rates were achieved when DCB-1 was grown in a methanogenic consortium. PMID:3426224

  6. Human body may produce bacteria.

    Science.gov (United States)

    Salerian, Alen J

    2017-06-01

    "Human body may produce bacteria" proposes that human body may produce bacteria and represent an independent source of infections contrary to the current paradigm of infectious disorders proposed by Louis Pasteur in 1880. The following observations are consistent with this hypothesis: A. Bidirectional transformations of both living and nonliving things have been commonly observed in nature. B. Complex multicellular organisms harbor the necessary properties to produce bacteria (water, nitrogen and oxygen). C. Physical laws suggest any previously observed phenomenon or action will occur again (life began on earth; a non living thing). D. Animal muscle cells may generate energy (fermentation). E. Sterilized food products (i.e. boiled eggs), may produce bacteria and fungus under special conditions and without any exposure to foreign living cells. "Human body may produce bacteria" may challenge the current medical paradigm that views human infectious disorders as the exclusive causative byproducts of invading foreign cells. It may also introduce new avenues to treat infectious disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Horizontal gene transfer between bacteria.

    Science.gov (United States)

    Heuer, Holger; Smalla, Kornelia

    2007-01-01

    Horizontal gene transfer (HGT) refers to the acquisition of foreign genes by organisms. The occurrence of HGT among bacteria in the environment is assumed to have implications in the risk assessment of genetically modified bacteria which are released into the environment. First, introduced genetic sequences from a genetically modified bacterium could be transferred to indigenous micro-organisms and alter their genome and subsequently their ecological niche. Second, the genetically modified bacterium released into the environment might capture mobile genetic elements (MGE) from indigenous micro-organisms which could extend its ecological potential. Thus, for a risk assessment it is important to understand the extent of HGT and genome plasticity of bacteria in the environment. This review summarizes the present state of knowledge on HGT between bacteria as a crucial mechanism contributing to bacterial adaptability and diversity. In view of the use of GM crops and microbes in agricultural settings, in this mini-review we focus particularly on the presence and role of MGE in soil and plant-associated bacteria and the factors affecting gene transfer.

  8. Nanofibrous solid dosage form of living bacteria prepared by electrospinning

    Directory of Open Access Journals (Sweden)

    I. Wagner

    2014-05-01

    Full Text Available The aim of this work was to investigate the suitability of electrospinning for biodrug delivery and to develop an electrospinning-based method to produce vaginal drug delivery systems. Lactobacillus acidophilus bacteria were encapsulated into nanofibers of three different polymers (polyvinyl alcohol and polyvinylpyrrolidone with two different molar masses. Shelf life of the bacteria could be enhanced by the exclusion of water and by preparing a solid dosage form, which is an advantageous and patient-friendly way of administration. The formulations were stored at –20, 7 and 25°C, respectively. Viability testing showed that the nanofibers can provide long term stability for huge amounts of living bacteria if they are kept at (or below 7°C. Furthermore, all kinds of nanowebs prepared in this work dissolved instantly when they got in contact with water, thus the developed biohybrid nanowebs can provide new potential ways for curing bacterial vaginosis.

  9. Psychobiotics and the Manipulation of Bacteria-Gut-Brain Signals.

    Science.gov (United States)

    Sarkar, Amar; Lehto, Soili M; Harty, Siobhán; Dinan, Timothy G; Cryan, John F; Burnet, Philip W J

    2016-11-01

    Psychobiotics were previously defined as live bacteria (probiotics) which, when ingested, confer mental health benefits through interactions with commensal gut bacteria. We expand this definition to encompass prebiotics, which enhance the growth of beneficial gut bacteria. We review probiotic and prebiotic effects on emotional, cognitive, systemic, and neural variables relevant to health and disease. We discuss gut-brain signalling mechanisms enabling psychobiotic effects, such as metabolite production. Overall, knowledge of how the microbiome responds to exogenous influence remains limited. We tabulate several important research questions and issues, exploration of which will generate both mechanistic insights and facilitate future psychobiotic development. We suggest the definition of psychobiotics be expanded beyond probiotics and prebiotics to include other means of influencing the microbiome. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Chitin Degradation In Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara; Machado, Henrique; Gram, Lone

    2015-01-01

    Introduction: Chitin is the most abundant polymer in the marine environment and the second most abundant in nature. Chitin does not accumulate on the ocean floor, because of microbial breakdown. Chitin degrading bacteria could have potential in the utilization of chitin as a renewable carbon...... and nitrogen source in the fermentation industry.Methods: Here, whole genome sequenced marine bacteria were screened for chitin degradation using phenotypic and in silico analyses.Results: The in silico analyses revealed the presence of three to nine chitinases in each strain, however the number of chitinases...... chitin regulatory system.Conclusions: This study has provided insight into the ecology of chitin degradation in marine bacteria. It also served as a basis for choosing a more efficient chitin degrading production strain e.g. for the use of chitin waste for large-scale fermentations....

  11. Methylotrophic bacteria in sustainable agriculture.

    Science.gov (United States)

    Kumar, Manish; Tomar, Rajesh Singh; Lade, Harshad; Paul, Diby

    2016-07-01

    Excessive use of chemical fertilizers to increase production from available land has resulted in deterioration of soil quality. To prevent further soil deterioration, the use of methylotrophic bacteria that have the ability to colonize different habitats, including soil, sediment, water, and both epiphytes and endophytes as host plants, has been suggested for sustainable agriculture. Methylotrophic bacteria are known to play a significant role in the biogeochemical cycle in soil ecosystems, ultimately fortifying plants and sustaining agriculture. Methylotrophs also improve air quality by using volatile organic compounds such as dichloromethane, formaldehyde, methanol, and formic acid. Additionally, methylotrophs are involved in phosphorous, nitrogen, and carbon cycling and can help reduce global warming. In this review, different aspects of the interaction between methylotrophs and host plants are discussed, including the role of methylotrophs in phosphorus acquisition, nitrogen fixation, phytohormone production, iron chelation, and plant growth promotion, and co-inoculation of these bacteria as biofertilizers for viable agriculture practices.

  12. Platelets and infections—complex interactions with bacteria

    Directory of Open Access Journals (Sweden)

    Hind eHAMZEH-COGNASSE

    2015-02-01

    Full Text Available Platelets can be considered sentinels of vascular system due to their high number in the circulation and to the range of functional immunoreceptors they express. Platelets express a wide range of potential bacterial receptors, including complement receptors, FcγRII, Toll-Like Receptors but also integrins conventionally described in the hemostatic response, such as GPIIb-IIIa or GPIb. Bacteria bind these receptors either directly, or indirectly via fibrinogen, fibronectin, the first complement C1q, the von Willebrand Factor, etc. The fate of platelet bound bacteria is questioned. Several studies reported the ability of activated platelets to internalize bacteria such as Staphylococcus aureus or Porphyromonas gingivalis, though there is no clue on what happens thereafter. Are they sheltered from the immune system in the cytoplasm of platelets or are they lysed? Indeed, while the presence of phagolysosome has not been demonstrated in platelets, they contain antimicrobial peptides that were shown to be efficient on S. aureus. Besides, the fact that bacteria can bind to platelets via receptors involved in hemostasis suggests that they may induce aggregation; this has indeed been described for Streptococcus sanguinis, S. epidermidis or C. pneumoniae. On the other hand, platelets are able to display an inflammatory response to an infectious triggering. We, and others, have shown that platelet release soluble immunomodulatory factors upon stimulation by bacterial components. Moreover, interactions between bacteria and platelets are not limited to only these two partners. Indeed, platelets are also essential for the formation of Neutrophil Extracellular Traps by neutrophils, resulting in bacterial clearance by trapping bacteria and concentrating antibacterial factors but in enhancing thrombosis. In conclusion, the platelet-bacteria interplay is a complex game; its fine analysis is complicated by the fact that the inflammatory component adds to the

  13. Transport of Chemotactic Bacteria in Porous Media with Structured Heterogeneity

    Science.gov (United States)

    Ford, R. M.; Wang, M.; Liu, J.; Long, T.

    2008-12-01

    Chemical contaminants that become trapped in low permeability zones (e.g. clay lenses) are difficult to remediate using conventional pump-and-treat approaches. Chemotactic bacteria that are transported by groundwater through more permeable regions may migrate toward these less permeable zones in response to chemical gradients created by contaminant diffusion from the low permeability source, thereby enhancing the remediation process by directing bacteria to the contaminants they degrade. What effect does the heterogeneity associated with coarse- and fine-grained layers that are characteristic of natural groundwater environments have on the transport of microorganisms and their chemotactic response? To address this question experiments were conducted over a range of scales from a single capillary tube to a laboratory- scale column in both static and flowing systems with and without chemoattractant gradients. In static capillary assays, motile bacteria accumulated at the interface between an aqueous solution and a suspension of agarose particulates. In microfluidic devices with an array of staggered cylinders, chemotactic bacteria migrated transverse to flow in response to a chemoattractant gradient. In sand columns packed with a coarse-grained core and surrounded by a fine-grained annulus, chemotactic bacteria migrated preferentially toward a chemoattractant source along the centerline. Mathematical models and computer simulations were developed to analyze the experimental observations in terms of transport parameters from the advection- disperson-sorption equation.

  14. Algae-bacteria interactions: Evolution, ecology and emerging applications.

    Science.gov (United States)

    Ramanan, Rishiram; Kim, Byung-Hyuk; Cho, Dae-Hyun; Oh, Hee-Mock; Kim, Hee-Sik

    2016-01-01

    Algae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as varied as deep seas to lichens and represent all conceivable modes of interactions - from mutualism to parasitism. Several studies have shown that algae and bacteria synergistically affect each other's physiology and metabolism, a classic case being algae-roseobacter interaction. These interactions are ubiquitous and define the primary productivity in most ecosystems. In recent years, algae have received much attention for industrial exploitation but their interaction with bacteria is often considered a contamination during commercialization. A few recent studies have shown that bacteria not only enhance algal growth but also help in flocculation, both essential processes in algal biotechnology. Hence, there is a need to understand these interactions from an evolutionary and ecological standpoint, and integrate this understanding for industrial use. Here we reflect on the diversity of such relationships and their associated mechanisms, as well as the habitats that they mutually influence. This review also outlines the role of these interactions in key evolutionary events such as endosymbiosis, besides their ecological role in biogeochemical cycles. Finally, we focus on extending such studies on algal-bacterial interactions to various environmental and bio-technological applications. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Release of Antibiotic Resistant Bacteria by a Waste Treatment Plant from Romania.

    Science.gov (United States)

    Lupan, Iulia; Carpa, Rahela; Oltean, Andreea; Kelemen, Beatrice Simona; Popescu, Octavian

    2017-09-27

    The occurrence and spread of bacterial antibiotic resistance are subjects of great interest, and the role of wastewater treatment plants has been attracting particular interest. These stations are a reservoir of bacteria, have a large range of organic and inorganic substances, and the amount of bacteria released into the environment is very high. The main purpose of the present study was to assess the removal degree of bacteria with resistance to antibiotics and identify the contribution of a wastewater treatment plant to the microbiota of Someşul Mic river water in Cluj county. The resistance to sulfamethoxazole and tetracycline and some of their representative resistance genes: sul1, tet(O), and tet(W) were assessed in this study. The results obtained showed that bacteria resistant to sulphonamides were more abundant than those resistant to tetracycline. The concentration of bacteria with antibiotic resistance changed after the treatment, namely, bacteria resistant to sulfamethoxazole. The removal of all bacteria and antibiotic-resistant bacteria was 98-99% and the degree of removal of bacteria resistant to tetracycline was higher than the bacteria resistant to sulfamethoxazole compared to total bacteria. The wastewater treatment plant not only contributed to elevating ARG concentrations, it also enhanced the possibility of horizontal gene transfer (HGT) by increasing the abundance of the intI1 gene. Even though the treatment process reduced the concentration of bacteria by two orders of magnitude, the wastewater treatment plant in Cluj-Napoca contributed to an increase in antibiotic-resistant bacteria concentrations up to 10 km downstream of its discharge in Someşul Mic river.

  16. ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

    DEFF Research Database (Denmark)

    Volpi, Marta

    2016-01-01

    solely based on endospores of sulphate-reducing bacteria (SRB), which presumably constitute only a small fraction of the total thermophilic endospore community reaching cold environments. My PhD project developed an experimental framework for using thermophilic fermentative endospores (TFEs) to trace...

  17. Alternative sources of Legionella bacteria

    NARCIS (Netherlands)

    van Heijnsbergen, H.H.L.

    2017-01-01

    Legionella bacteria can cause Legionnaires’ disease (LD) in humans. Symptoms of LD can range from mild disease to severe pneumonia with sometimes fatal outcome. In the Netherlands, the most important infective agent is Legionella pneumophila. L. pneumophila infection is associated with aquatic

  18. Programmed survival of soil bacteria

    DEFF Research Database (Denmark)

    Jensen, Lars Bogø; Molin, Søren; Sternberg, Claus

    Biological containment systems have been developed for Pseudomonas putida and related soil bacteria. The systems are based on combinations of lethal genes and regulated gene expression. Two types of killing function have been employed: 1) A membrane protein interfering with the membrane potential...

  19. Automated radiometric detection of bacteria

    International Nuclear Information System (INIS)

    Waters, J.R.

    1974-01-01

    A new radiometric method called BACTEC, used for the detection of bacteria in cultures or in supposedly sterile samples, was discussed from the standpoint of methodology, both automated and semi-automated. Some of the results obtained so far were reported and some future applications and development possibilities were described. In this new method, the test sample is incubated in a sealed vial with a liquid culture medium containing a 14 C-labeled substrate. If bacteria are present, they break down the substrate, producing 14 CO 2 which is periodically extracted from the vial as a gas and is tested for radioactivity. If this gaseous radioactivity exceeds a threshold level, it is evidence of bacterial presence and growth in the test vial. The first application was for the detection of bacteria in the blood cultures of hospital patients. Data were presented showing typical results. Also discussed were future applications, such as rapid screening for bacteria in urine industrial sterility testing and the disposal of used 14 C substrates. (Mukohata, S.)

  20. Synthetic Biology in Streptomyces Bacteria

    NARCIS (Netherlands)

    Medema, Marnix H.; Breitling, Rainer; Takano, Eriko

    2011-01-01

    Actinomycete bacteria of the genus Streptomyces are major producers of bioactive compounds for the biotechnology industry. They are the source of most clinically used antibiotics, as well as of several widely used drugs against common diseases, including cancer . Genome sequencing has revealed that

  1. Deodorant bacteria; Des bacteries desodorisantes

    Energy Technology Data Exchange (ETDEWEB)

    Fanlo, J.L. [Ecole Nationale Superieure des Mines, 30 - Ales (France)

    1998-02-01

    Purifying bacteria: if this concept is not new, its application to gases cleansing has only been developed recently. This method allows to eliminate the volatile organic compounds and the gaseous effluents odors which come from industrial sites. Three bioreactors types exist at the present time. Their principles are explained. (O.M.) 6 refs.

  2. Fuzzy species among recombinogenic bacteria

    Directory of Open Access Journals (Sweden)

    Fraser Christophe

    2005-03-01

    Full Text Available Abstract Background It is a matter of ongoing debate whether a universal species concept is possible for bacteria. Indeed, it is not clear whether closely related isolates of bacteria typically form discrete genotypic clusters that can be assigned as species. The most challenging test of whether species can be clearly delineated is provided by analysis of large populations of closely-related, highly recombinogenic, bacteria that colonise the same body site. We have used concatenated sequences of seven house-keeping loci from 770 strains of 11 named Neisseria species, and phylogenetic trees, to investigate whether genotypic clusters can be resolved among these recombinogenic bacteria and, if so, the extent to which they correspond to named species. Results Alleles at individual loci were widely distributed among the named species but this distorting effect of recombination was largely buffered by using concatenated sequences, which resolved clusters corresponding to the three species most numerous in the sample, N. meningitidis, N. lactamica and N. gonorrhoeae. A few isolates arose from the branch that separated N. meningitidis from N. lactamica leading us to describe these species as 'fuzzy'. Conclusion A multilocus approach using large samples of closely related isolates delineates species even in the highly recombinogenic human Neisseria where individual loci are inadequate for the task. This approach should be applied by taxonomists to large samples of other groups of closely-related bacteria, and especially to those where species delineation has historically been difficult, to determine whether genotypic clusters can be delineated, and to guide the definition of species.

  3. Bioremediation of toxic substances by mercury resistant marine bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    De, J.; Sarkar, A.; Ramaiah, N.

    : ramaiah@nio.org Introduction: The principal goal of bioremediation is to enhance the natural biological-chemical transformations that render pollutants harmless as minerals and thus to provide a relief and, if feasible, a permanent solution...). The combination of soil bioleaching and bioprecipitation of the leached metals, by sulfate reducing bacteria, proved to be effective in removing and concentrating a range of metals, including Zn, Cu and Cd from metal-contaminated soils (White et al., 1998...

  4. Endophytic bacteria: prospects and applications for the phytoremediation of organic pollutants.

    Science.gov (United States)

    Afzal, Muhammad; Khan, Qaiser M; Sessitsch, Angela

    2014-12-01

    Recently, there has been an increased effort to enhance the efficacy of phytoremediation of contaminated environments by exploiting plant-microbe interactions. The combined use of plants and endophytic bacteria is an emerging approach for the clean-up of soil and water polluted with organic compounds. In plant-endophyte partnerships, plants provide the habitat as well as nutrients to their associated endophytic bacteria. In response, endophytic bacteria with appropriate degradation pathways and metabolic activities enhance degradation of organic pollutants, and diminish phytotoxicity and evapotranspiration of organic pollutants. Moreover, endophytic bacteria possessing plant growth-promoting activities enhance the plant's adaptation and growth in soil and water contaminated with organic pollutants. Overall, the application of endophytic bacteria gives new insights into novel protocols to improve phytoremediation efficiency. However, successful application of plant-endophyte partnerships for the clean-up of an environment contaminated with organic compounds depends on the abundance and activity of the degrading endophyte in different plant compartments. Although many endophytic bacteria have the potential to degrade organic pollutants and improve plant growth, their contribution to enhance phytoremediation efficiency is still underestimated. A better knowledge of plant-endophyte interactions could be utilized to increase the remediation of polluted soil environments and to protect the foodstuff by decreasing agrochemical residues in food crops. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Genetics of Lactic Acid Bacteria

    Science.gov (United States)

    Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

  6. Re-engineering bacteria for ethanol production

    Science.gov (United States)

    Yomano, Lorraine P; York, Sean W; Zhou, Shengde; Shanmugam, Keelnatham; Ingram, Lonnie O

    2014-05-06

    The invention provides recombinant bacteria, which comprise a full complement of heterologous ethanol production genes. Expression of the full complement of heterologous ethanol production genes causes the recombinant bacteria to produce ethanol as the primary fermentation product when grown in mineral salts medium, without the addition of complex nutrients. Methods for producing the recombinant bacteria and methods for producing ethanol using the recombinant bacteria are also disclosed.

  7. Oligotrophic bacteria isolated from clinical materials.

    OpenAIRE

    Tada, Y; Ihmori, M; Yamaguchi, J

    1995-01-01

    Oligotrophic bacteria (oligotrophs) are microorganisms that grow in extremely nutritionally deficient conditions in which the concentrations of organic substances are low. Many oligotrophic bacteria were isolated from clinical materials including urine, sputum, swabbings of the throat, vaginal discharges, and others. Seventy-seven strains of oligotrophic bacteria from 871 samples of clinical material were isolated. A relatively higher frequency of isolation of oligotrophic bacteria was shown ...

  8. Geobiology of Marine Magnetotactic Bacteria

    Science.gov (United States)

    2006-06-01

    prokaryotic cells of diverse phylogeny when grown in media containing 45 1mM iron, suggesting some kind of detoxification function . The inclusions were...salt marsh productivity. FISH also showed that aggregates consist of genetically identical cells. QPCR data indicated that populations are finely...my advisor Katrina Edwards for taking a chance on someone who initially knew nothing about magnetotactic bacteria, microbial ecology , or microbiology

  9. Nitrogen-fixing methane-utilizing bacteria

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1976-01-01

    Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in

  10. Laser-Based Identification of Pathogenic Bacteria

    Science.gov (United States)

    Rehse, Steven J.

    2009-01-01

    Bacteria are ubiquitous in our world. From our homes, to our work environment, to our own bodies, bacteria are the omnipresent although often unobserved companions to human life. Physicists are typically untroubled professionally by the presence of these bacteria, as their study usually falls safely outside the realm of our typical domain. In the…

  11. Current strategies for improving food bacteria

    NARCIS (Netherlands)

    Kuipers, O P; Buist, Girbe; Kok, Jan

    2000-01-01

    Novel concepts and methodologies are emerging that hold great promise for the directed improvement of food-related bacteria, specifically lactic acid bacteria. Also, the battle against food spoilage and pathogenic bacteria can now be fought more effectively. Here we describe recent advances in

  12. Ecology of mycophagous collimonas bacteria in soil

    NARCIS (Netherlands)

    Höppener-Ogawa, Sachie

    2008-01-01

    Bacteria belonging to the genus Collimonas consist of soil bacteria that can grow at expense of living fungal hyphae i.e. they are mycophagous. This PhD studies deals with the ecology of mycophagous bacteria in soil using collimonads as model organisms. Collimonads were found to be widely

  13. Commensal Bacteria Aid Mate-selection in the Fruit Fly, Bactrocera dorsalis.

    Science.gov (United States)

    Damodaram, Kamala Jayanthi Pagadala; Ayyasamy, Arthikirubha; Kempraj, Vivek

    2016-10-01

    Commensal bacteria influence many aspects of an organism's behaviour. However, studies on the influence of commensal bacteria in insect mate-selection are scarce. Here, we present empirical evidence that commensal bacteria mediate mate-selection in the Oriental fruit fly, Bactrocera dorsalis. Male flies were attracted to female flies, but this attraction was abolished when female flies were fed with antibiotics, suggesting the role of the fly's microbiota in mediating mate-selection. We show that male flies were attracted to and ejaculated more sperm into females harbouring the microbiota. Using culturing and 16S rDNA sequencing, we isolated and identified different commensal bacteria, with Klebsiella oxytoca being the most abundant bacterial species. This preliminary study will enhance our understanding of the influence of commensal bacteria on mate-selection behaviour of B. dorsalis and may find use in devising control operations against this devastating pest.

  14. Low field orientation magnetic separation methods for magnetotactic bacteria

    International Nuclear Information System (INIS)

    Moeschler, F.D.

    1999-01-01

    range of motility inhibiting ions is such that MTB cannot be envisaged for general wastewater applications. Radionucleide studies were undertaken targeting a niche application where this metal ion restriction would not apply. Liquid scintillation and γ-ray counting measurements indicated that magnetotactic bacteria accumulate high levels of both plutonium and mercury. A number of both static and flow recovery separators for magnetotactic bacteria were developed. Statistical models predicting the behaviour of these separators were compared to measured results. These comparisons highlighted the problems of 'wash off' of accumulated bacteria in separators where flow was present. The most successful of the flow recovery designs - the channel separator - was then tested using a simulated effluent that contained plutonium. The results confirmed both previous radioisotope uptake studies and separator test results. The channel separator design was enhanced by the introduction of wire arrays into the separation chamber. Orientation magnetic separation in these hybrid-type separators was used to accumulate the biomass and the magnetic gradients generated by the wire arrays to retain the bacteria on the separator walls. These separators achieved increases in efficiency of up to 300% compared with the channel separator. In summary, this thesis describes a successful separation process for the recovery of motile MTB. However, to apply this separator approach to the suggested radioisotope application would require successful large scale culturing. (author)

  15. AIDS: "it's the bacteria, stupid!".

    Science.gov (United States)

    Broxmeyer, Lawrence; Cantwell, Alan

    2008-11-01

    Acid-fast tuberculous mycobacterial infections are common in AIDS and are regarded as secondary "opportunistic infections." According to the National Institute of Allergy and Infectious Diseases, TB is the major attributable cause of death in AIDS patients. Could such bacteria play a primary or causative role in AIDS? Certainly, In screening tests for HIV, there is frequent, up to 70%, cross-reactivity, between the gag and pol proteins of HIV and patients with mycobacterial infections such as tuberculosis. By 1972, five years before gays started dying in the U.S., Rolland wrote Genital Tuberculosis, a Forgotten Disease? And ironically, in 1979, on the eve of AIDS recognition, Gondzik and Jasiewicz showed that even in the laboratory, genitally infected tubercular male guinea pigs could infect healthy females through their semen by an HIV-compatible ratio of 1 in 6 or 17%, prompting him to warn his patients that not only was tuberculosis a sexually transmitted disease, but also the necessity of the application of suitable contraceptives, such as condoms, to avoid it. Gondzik's solution and date of publication are chilling; his findings significant. Since 1982 Cantwell et al found acid-fast bacteria closely related to tuberculosis (TB) and atypical tuberculosis in AIDS tissue. On the other hand molecular biologist and virologist Duesberg, who originally defined retroviral ultrastructure, has made it clear that HIV is not the cause of AIDS and that the so-called AIDS retrovirus has never been isolated in its pure state. Dr. Etienne de Harven, first to examine retroviruses under the electron, agrees. In 1993 HIV co-discoverer Luc Montagnier reported on cell-wall-deficient (CWD) bacteria which he called "mycoplasma" in AIDS tissue. He suspected these as a necessary "co-factor" for AIDS. Remarkably, Montagnier remained silent on Cantwell's reports of acid-fast bacteria which could simulate "mycoplasma" in AIDS tissue. Mattman makes clear that the differentiation between

  16. Characterization of mercury bioremediation by transgenic bacteria expressing metallothionein and polyphosphate kinase

    Directory of Open Access Journals (Sweden)

    Gonzalez-Ruiz Gloriene

    2011-08-01

    Full Text Available Abstract Background The use of transgenic bacteria has been proposed as a suitable alternative for mercury remediation. Ideally, mercury would be sequestered by metal-scavenging agents inside transgenic bacteria for subsequent retrieval. So far, this approach has produced limited protection and accumulation. We report here the development of a transgenic system that effectively expresses metallothionein (mt-1 and polyphosphate kinase (ppk genes in bacteria in order to provide high mercury resistance and accumulation. Results In this study, bacterial transformation with transcriptional and translational enhanced vectors designed for the expression of metallothionein and polyphosphate kinase provided high transgene transcript levels independent of the gene being expressed. Expression of polyphosphate kinase and metallothionein in transgenic bacteria provided high resistance to mercury, up to 80 μM and 120 μM, respectively. Here we show for the first time that metallothionein can be efficiently expressed in bacteria without being fused to a carrier protein to enhance mercury bioremediation. Cold vapor atomic absorption spectrometry analyzes revealed that the mt-1 transgenic bacteria accumulated up to 100.2 ± 17.6 μM of mercury from media containing 120 μM Hg. The extent of mercury remediation was such that the contaminated media remediated by the mt-1 transgenic bacteria supported the growth of untransformed bacteria. Cell aggregation, precipitation and color changes were visually observed in mt-1 and ppk transgenic bacteria when these cells were grown in high mercury concentrations. Conclusion The transgenic bacterial system described in this study presents a viable technology for mercury bioremediation from liquid matrices because it provides high mercury resistance and accumulation while inhibiting elemental mercury volatilization. This is the first report that shows that metallothionein expression provides mercury resistance and

  17. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    OpenAIRE

    Denoncourt, Alix M.; Paquet, Valérie E.; Charette, Steve J.

    2014-01-01

    Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging...

  18. Lactic acid bacteria as a cell factory for riboflavin production.

    Science.gov (United States)

    Thakur, Kiran; Tomar, Sudhir Kumar; De, Sachinandan

    2016-07-01

    Consumers are increasingly becoming aware of their health and nutritional requirements, and in this context, vitamins produced in situ by microbes may suit their needs and expectations. B groups vitamins are essential components of cellular metabolism and among them riboflavin is one of the vital vitamins required by bacteria, plants, animals and humans. Here, we focus on the importance of microbial production of riboflavin over chemical synthesis. In addition, genetic abilities for riboflavin biosynthesis by lactic acid bacteria are discussed. Genetically modified strains by employing genetic engineering and chemical analogues have been developed to enhance riboflavin production. The present review attempts to collect the currently available information on riboflavin production by microbes in general, while placing greater emphasis on food grade lactic acid bacteria and human gut commensals. For designing riboflavin-enriched functional foods, proper selection and exploitation of riboflavin-producing lactic acid bacteria is essential. Moreover, eliminating the in situ vitamin fortification step will decrease the cost of food production. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  19. Differential effects of catecholamines on in vitro growth of pathogenic bacteria

    Science.gov (United States)

    Belay, Tesfaye; Sonnenfeld, Gerald

    2002-01-01

    Supplementation of minimal medium inoculated with bacterial cultures with norepinephrine, epinephrine, dopamine, or isoproterenol resulted in marked increases in growth compared to controls. Norepinephrine and dopamine had the greatest enhancing effects on growth of cultures of Pseudomonas aeruginosa and Klebsiella pneumoniae, while epinephrine and isoproterenol also enhanced growth to a lesser extent. The growth of Escherichia coli in the presence of norepinephrine was greater than growth in the presence of the three other neurochemicals used in the study. Growth of Staphylococcus aureus was also enhanced in the presence of norepinephrine, but not to the same degree as was the growth of gram negative bacteria. Addition of culture supernatants from E. coli cultures that had been grown in the presence of norepinephrine was able to enhance the growth of K. pneumoniae. Addition of the culture supernatant fluid culture from E. coli cultures that had been grown in the presence of norepinephrine did not enhance growth of P. aeruginosa or S. aureus. Culture supernatant fluids from bacteria other than E. coli grown in the presence of norepinephrine were not able to enhance the growth of any bacteria tested. The results suggest that catecholamines can enhance growth of pathogenic bacteria, which may contribute to development of pathogenesis; however, there is no uniform effect of catecholamines on bacterial growth.

  20. Endocarditis caused by anaerobic bacteria.

    Science.gov (United States)

    Kestler, M; Muñoz, P; Marín, M; Goenaga, M A; Idígoras Viedma, P; de Alarcón, A; Lepe, J A; Sousa Regueiro, D; Bravo-Ferrer, J M; Pajarón, M; Costas, C; García-López, M V; Hidalgo-Tenorio, C; Moreno, M; Bouza, E

    2017-10-01

    Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES). We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria). Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%). IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Bacteria and vampirism in cinema.

    Science.gov (United States)

    Castel, O; Bourry, A; Thévenot, S; Burucoa, C

    2013-09-01

    A vampire is a non-dead and non-alive chimerical creature, which, according to various folklores and popular superstitions, feeds on blood of the living to draw vital force. Vampires do not reproduce by copulation, but by bite. Vampirism is thus similar to a contagious disease contracted by intravascular inoculation with a suspected microbial origin. In several vampire films, two real bacteria were staged, better integrated than others in popular imagination: Yersinia pestis and Treponema pallidum. Bacillus vampiris was created for science-fiction. These films are attempts to better define humans through one of their greatest fears: infectious disease. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  2. Pathogenic mechanisms of intracellular bacteria.

    Science.gov (United States)

    Niller, Hans Helmut; Masa, Roland; Venkei, Annamária; Mészáros, Sándor; Minarovits, Janos

    2017-06-01

    We wished to overview recent data on a subset of epigenetic changes elicited by intracellular bacteria in human cells. Reprogramming the gene expression pattern of various host cells may facilitate bacterial growth, survival, and spread. DNA-(cytosine C5)-methyltransferases of Mycoplasma hyorhinis targeting cytosine-phosphate-guanine (CpG) dinucleotides and a Mycobacterium tuberculosis methyltransferase targeting non-CpG sites methylated the host cell DNA and altered the pattern of gene expression. Gene silencing by CpG methylation and histone deacetylation, mediated by cellular enzymes, also occurred in M. tuberculosis-infected macrophages. M. tuberculosis elicited cell type-specific epigenetic changes: it caused increased DNA methylation in macrophages, but induced demethylation, deposition of euchromatic histone marks and activation of immune-related genes in dendritic cells. A secreted transposase of Acinetobacter baumannii silenced a cellular gene, whereas Mycobacterium leprae altered the epigenotype, phenotype, and fate of infected Schwann cells. The 'keystone pathogen' oral bacterium Porphyromonas gingivalis induced local DNA methylation and increased the level of histone acetylation in host cells. These epigenetic changes at the biofilm-gingiva interface may contribute to the development of periodontitis. Epigenetic regulators produced by intracellular bacteria alter the epigenotype and gene expression pattern of host cells and play an important role in pathogenesis.

  3. Money and transmission of bacteria.

    Science.gov (United States)

    Gedik, Habip; Voss, Timothy A; Voss, Andreas

    2013-08-28

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria to people who come in contact with the banknotes. The survival rate was highest for the Romanian Leu yielding all three microorganisms used after both three and six hours of drying. Furthermore, the Leu was the only banknote to yield VRE after one day of drying. Other currencies either enabled the survival of Extended-Spectrum Beta-Lactamases (ESBL) and VRE (e.g. Euro), but not of MRSA, or the other way round (e.g. US Dollar). While a variety of factors such as community hygiene levels, people's behaviour, and antimicrobial resistance rates at community level obviously have influence on the transmission of resistant microorganisms, the type of banknote-paper may be an additional variable to consider.

  4. Resistance of Bacteria to Biocides.

    Science.gov (United States)

    Maillard, Jean-Yves

    2018-04-01

    Biocides and formulated biocides are used worldwide for an increasing number of applications despite tightening regulations in Europe and in the United States. One concern is that such intense usage of biocides could lead to increased bacterial resistance to a product and cross-resistance to unrelated antimicrobials including chemotherapeutic antibiotics. Evidence to justify such a concern comes mostly from the use of health care-relevant bacterial isolates, although the number of studies of the resistance characteristics of veterinary isolates to biocides have increased the past few years. One problem remains the definition of "resistance" and how to measure resistance to a biocide. This has yet to be addressed globally, although the measurement of resistance is becoming more pressing, with regulators both in Europe and in the United States demanding that manufacturers provide evidence that their biocidal products will not impact on bacterial resistance. Alongside in vitro evidence of potential antimicrobial cross-resistance following biocide exposure, our understanding of the mechanisms of bacterial resistance and, more recently, our understanding of the effect of biocides to induce a mechanism(s) of resistance in bacteria has improved. This article aims to provide an understanding of the development of antimicrobial resistance in bacteria following a biocide exposure. The sections provide evidence of the occurrence of bacterial resistance and its mechanisms of action and debate how to measure bacterial resistance to biocides. Examples pertinent to the veterinary field are used where appropriate.

  5. Differential scanning calorimetry of bacteria.

    Science.gov (United States)

    Miles, C A; Mackey, B M; Parsons, S E

    1986-04-01

    Thermograms obtained by differential scanning calorimetry of a range of bacteria of different heat resistances were compared. Equations were derived to calculate the rate at which the numbers of viable organisms in a calorimeter decline as the temperature is raised at a constant rate. Vegetative bacteria scanned at 10 degrees C min-1 showed multi-peaked thermograms with four major peaks (denoted m, n, p and q) occurring in the regions 68-73, 77-84, 89-99 and 105-110 degrees C respectively. Exceptions were that peak m (the largest peak) occurred at 79-82 degrees C in Bacillus stearothermophilus and an additional peak, r, was detected in Escherichia coli at 119 degrees C. At temperatures below the main peak m there were major differences in thermograms between species. There was a direct relationship between the onset of thermal denaturation and the thermoresistance of different organisms. Heat-sensitive organisms displayed thermogram features which were absent in the more heat-resistant types. When samples were cooled to 5 degrees C and re-heated, a small endothermic peak, pr, was observed at the same temperature as p. Peaks p and pr were identified as the melting endotherms of DNA. In all vegetative organisms examined, maximum death rates, computed from published D and z values, occurred at temperatures above the onset of thermal denaturation, i.e. cell death and irreversible denaturation of cell components occurred within the same temperature range.

  6. Microeconomic principles explain an optimal genome size in bacteria.

    Science.gov (United States)

    Ranea, Juan A G; Grant, Alastair; Thornton, Janet M; Orengo, Christine A

    2005-01-01

    Bacteria can clearly enhance their survival by expanding their genetic repertoire. However, the tight packing of the bacterial genome and the fact that the most evolved species do not necessarily have the biggest genomes suggest there are other evolutionary factors limiting their genome expansion. To clarify these restrictions on size, we studied those protein families contributing most significantly to bacterial-genome complexity. We found that all bacteria apply the same basic and ancestral 'molecular technology' to optimize their reproductive efficiency. The same microeconomics principles that define the optimum size in a factory can also explain the existence of a statistical optimum in bacterial genome size. This optimum is reached when the bacterial genome obtains the maximum metabolic complexity (revenue) for minimal regulatory genes (logistic cost).

  7. Sulfur metabolism in phototrophic sulfur bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Dahl, Christiane

    2008-01-01

    Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB......). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms...... in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative...

  8. Plutonium speciation affected by environmental bacteria

    International Nuclear Information System (INIS)

    Neu, M.P.; Icopini, G.A.; Boukhalfa, H.

    2005-01-01

    Plutonium has no known biological utility, yet it has the potential to interact with bacterial cellular and extracellular structures that contain metal-binding groups, to interfere with the uptake and utilization of essential elements, and to alter cell metabolism. These interactions can transform plutonium from its most common forms, solid, mineral-adsorbed, or colloidal Pu(IV), to a variety of biogeochemical species that have much different physico-chemical properties. Organic acids that are extruded products of cell metabolism can solubilize plutonium and then enhance its environmental mobility, or in some cases facilitate plutonium transfer into cells. Phosphate- and carboxylate-rich polymers associated with cell walls can bind plutonium to form mobile biocolloids or Pu-laden biofilm/mineral solids. Bacterial membranes, proteins or redox agents can produce strongly reducing electrochemical zones and generate molecular Pu(III/IV) species or oxide particles. Alternatively, they can oxidize plutonium to form soluble Pu(V) or Pu(VI) complexes. This paper reviews research on plutonium-bacteria interactions and closely related studies on the biotransformation of uranium and other metals. (orig.)

  9. Bactericide for sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Shklyar, T F; Anoshina, G M; Blokhin, V Ye; Kisarrev, Ye L; Novikovsa, G M

    1981-01-01

    The aim of the invention is to find a bactericide for sulfate-reducing bacteria of oil fields in Western Siberia in order to suppress the biocorrosive activity on oil industry equipment. This goal is achieved by using M-nitroacetanylide as the bactericide of sulfate-reducing bacteria. This agent suppresses the activity of a stored culture of sulfate-reducing bacteria that comes from industrial waste waters injection wells of the Smotlor oil field.

  10. Differential staining of bacteria: acid fast stain.

    Science.gov (United States)

    Reynolds, Jackie; Moyes, Rita B; Breakwell, Donald P

    2009-11-01

    Acid-fastness is an uncommon characteristic shared by the genera Mycobacterium (Section 10A) and Nocardia. Because of this feature, this stain is extremely helpful in identification of these bacteria. Although Gram positive, acid-fast bacteria do not take the crystal violet into the wall well, appearing very light purple rather than the deep purple of normal Gram-positive bacteria. (c) 2009 by John Wiley & Sons, Inc.

  11. Transformation of gram positive bacteria by sonoporation

    Science.gov (United States)

    Yang, Yunfeng; Li, Yongchao

    2014-03-11

    The present invention provides a sonoporation-based method that can be universally applied for delivery of compounds into Gram positive bacteria. Gram positive bacteria which can be transformed by sonoporation include, for example, Bacillus, Streptococcus, Acetobacterium, and Clostridium. Compounds which can be delivered into Gram positive bacteria via sonoporation include nucleic acids (DNA or RNA), proteins, lipids, carbohydrates, viruses, small organic and inorganic molecules, and nano-particles.

  12. Magnetotactic bacteria at the geomagnetic equator

    International Nuclear Information System (INIS)

    Frankel, R.B.; Blakemore, R.P.; Araujo, F.F.T. de; Esquivel, D.M.S.; Danon, J.

    1981-01-01

    Magnetotatic bacteria are observed in freshwater and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments. (Author) [pt

  13. Bioenergetics of photoheterotrophic bacteria in the oceans.

    Science.gov (United States)

    Kirchman, David L; Hanson, Thomas E

    2013-04-01

    Photoheterotrophic microbes, such as proteorhodopsin (PR)-based phototrophic (PRP) and aerobic anoxygenic phototrophic (AAP) bacteria, are well known to be abundant in the oceans, potentially playing unique roles in biogeochemical cycles. However, the contribution of phototrophy to the energy requirements of these bacteria has not been quantitatively examined to date. To better understand the implications of photoheterophy in the oceans, we calculated energy benefits and costs of phototrophy and compared net benefits with maintenance costs. Benefits depend on the number of photosynthetic units (PSUs), absorption cross-section area of each PSU as function of wavelength, the in situ light quality, and the energy yield per absorbed photon. For costs we considered the energy required for the synthesis of pigments, amino acids and proteins in each PSU. Our calculations indicate that AAP bacteria harvest more light energy than do PRP bacteria, but the costs of phototrophy are much higher for AAP bacteria. Still, the net energy gained by AAP bacteria is often sufficient to meet maintenance costs, while that is not the case for PRP bacteria except with high light intensities and large numbers of proteorhodopsin molecules per cell. The low costs and simplicity of PR-based phototrophy explain the high abundance of proteorhodopsin genes in the oceans. However, even for AAP bacteria, the net energy yield of phototrophy is apparently too low to influence the distribution of photoheterotrophic bacteria among various marine systems. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  14. Quorum sensing in gram-negative bacteria

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.; Høiby, N.

    2004-01-01

    Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community, and the mechanism is referred to as quorum sensing (QS). Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal...... molecules. Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread. These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment...

  15. Isolation and characterization of methanogenic bacteria from ...

    African Journals Online (AJOL)

    Isolation and characterization of methanogenic bacteria from brewery wastewater in Kenya. Sylvia Injete Murunga, Duncan Onyango Mbuge, Ayub Njoroge Gitau, Urbanus Ndungwa Mutwiwa, Ingrid Namae Wekesa ...

  16. Fewer bacteria in warm water

    International Nuclear Information System (INIS)

    Bagh, Lene

    1999-01-01

    There has been many suggestions to how the ideal warm water system should be. Particularly whether warm water containers or heat exchangers in larger houses are the best solutions in order to maintain a water quality with low levels of bacteria. In an investigation made by Statens Byggeforskningsinstitutt (Denmark) regarding ''Bacterial growth in warm water installations with heat exchangers'' there were used several heat exchangers made by Gjelsted and Lund of three of which had HWAT heating cables. The bacterial content was low from these exchangers compared to exchangers with circulation. The article presents promising results from a study where the method was investigated over a longer period in two new larger warm water systems. Some energy conservation aspects are discussed

  17. Modeling Political Populations with Bacteria

    Science.gov (United States)

    Cleveland, Chris; Liao, David

    2011-03-01

    Results from lattice-based simulations of micro-environments with heterogeneous nutrient resources reveal that competition between wild-type and GASP rpoS819 strains of E. Coli offers mutual benefit, particularly in nutrient deprived regions. Our computational model spatially maps bacteria populations and energy sources onto a set of 3D lattices that collectively resemble the topology of North America. By implementing Wright-Fishcer re- production into a probabilistic leap-frog scheme, we observe populations of wild-type and GASP rpoS819 cells compete for resources and, yet, aid each other's long term survival. The connection to how spatial political ideologies map in a similar way is discussed.

  18. Cell Size Regulation in Bacteria

    Science.gov (United States)

    Amir, Ariel

    2014-05-01

    Various bacteria such as the canonical gram negative Escherichia coli or the well-studied gram positive Bacillus subtilis divide symmetrically after they approximately double their volume. Their size at division is not constant, but is typically distributed over a narrow range. Here, we propose an analytically tractable model for cell size control, and calculate the cell size and interdivision time distributions, as well as the correlations between these variables. We suggest ways of extracting the model parameters from experimental data, and show that existing data for E. coli supports partial size control, and a particular explanation: a cell attempts to add a constant volume from the time of initiation of DNA replication to the next initiation event. This hypothesis accounts for the experimentally observed correlations between mother and daughter cells as well as the exponential dependence of size on growth rate.

  19. Antioxidant Properties of Probiotic Bacteria.

    Science.gov (United States)

    Wang, Yang; Wu, Yanping; Wang, Yuanyuan; Xu, Han; Mei, Xiaoqiang; Yu, Dongyou; Wang, Yibing; Li, Weifen

    2017-05-19

    Oxidative stress defines a condition in which the prooxidant-antioxidant balance in the cell is disturbed, resulting in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells' viability. Probiotics have been known for many beneficial health effects, and the consumption of probiotics alone or in food shows that strain-specific probiotics can present antioxidant activity and reduce damages caused by oxidation. However, the oxidation-resistant ability of probiotics, especially the underling mechanisms, is not properly understood. In this view, there is interest to figure out the antioxidant property of probiotics and summarize the mode of action of probiotic bacteria in antioxidation. Therefore, in the present paper, the antioxidant mechanisms of probiotics have been reviewed in terms of their ability to improve the antioxidant system and their ability to decrease radical generation. Since in recent years, oxidative stress has been associated with an altered gut microbiota, the effects of probiotics on intestinal flora composition are also elaborated.

  20. Sterol Synthesis in Diverse Bacteria.

    Science.gov (United States)

    Wei, Jeremy H; Yin, Xinchi; Welander, Paula V

    2016-01-01

    Sterols are essential components of eukaryotic cells whose biosynthesis and function has been studied extensively. Sterols are also recognized as the diagenetic precursors of steranes preserved in sedimentary rocks where they can function as geological proxies for eukaryotic organisms and/or aerobic metabolisms and environments. However, production of these lipids is not restricted to the eukaryotic domain as a few bacterial species also synthesize sterols. Phylogenomic studies have identified genes encoding homologs of sterol biosynthesis proteins in the genomes of several additional species, indicating that sterol production may be more widespread in the bacterial domain than previously thought. Although the occurrence of sterol synthesis genes in a genome indicates the potential for sterol production, it provides neither conclusive evidence of sterol synthesis nor information about the composition and abundance of basic and modified sterols that are actually being produced. Here, we coupled bioinformatics with lipid analyses to investigate the scope of bacterial sterol production. We identified oxidosqualene cyclase (Osc), which catalyzes the initial cyclization of oxidosqualene to the basic sterol structure, in 34 bacterial genomes from five phyla (Bacteroidetes, Cyanobacteria, Planctomycetes, Proteobacteria, and Verrucomicrobia) and in 176 metagenomes. Our data indicate that bacterial sterol synthesis likely occurs in diverse organisms and environments and also provides evidence that there are as yet uncultured groups of bacterial sterol producers. Phylogenetic analysis of bacterial and eukaryotic Osc sequences confirmed a complex evolutionary history of sterol synthesis in this domain. Finally, we characterized the lipids produced by Osc-containing bacteria and found that we could generally predict the ability to synthesize sterols. However, predicting the final modified sterol based on our current knowledge of sterol synthesis was difficult. Some bacteria

  1. Plant-bacteria partnership: phytoremediation of hydrocarbons contaminated soil and expression of catabolic genes

    Directory of Open Access Journals (Sweden)

    Hamna Saleem

    2016-01-01

    Full Text Available Petroleum hydrocarbons are harmful to living organisms when they are exposed in natural environment. Once they come in contact, it is not an easy to remove them because many of their constituents are persistent in nature. To achieve this target, different approaches have been exploited by using plants, bacteria, and plant-bacteria together. Among them, combined use of plants and bacteria has gained tremendous attention as bacteria possess set of catabolic genes which produce catabolic enzymes to decontaminate hydrocarbons. In return, plant ooze out root exudates containing nutrients and necessary metabolites which facilitate the microbial colonization in plant rhizosphere. This results into high gene abundance and gene expression in the rhizosphere and, thus, leads to enhanced degradation. Moreover, high proportions of beneficial bacteria helps plant to gain more biomass due to their plant growth promoting activities and production of phytohromones. This review focuses functioning and mechanisms of catabolic genes responsible for degradation of straight chain and aromatic hydrocarbons with their potential of degradation in bioremediation. With the understanding of expression mechanisms, rate of degradation can be enhanced by adjusting environmental factors and acclimatizing plant associated bacteria in plant rhizosphere.

  2. Effect of adaptation and pulp density on bioleaching of mine waste using indigenous acidophilic bacteria

    Science.gov (United States)

    Cho, K.; Kim, B.; Lee, D.; Choi, N.; Park, C.

    2011-12-01

    Adaptation to environment is a natural phenomena that takes place in many animals, plants and microorganisms. These adapted organisms achieve stronger applicability than unadapted organisms after habitation in a specific environment for a long time. In the biohydrometallurgical industry, adaptation to special environment conditions by selective culturing is the most popular method for improving bioleaching activity of strains-although that is time consuming. This study investigated the influence of the bioleaching efficiency of mine waste under batch experimental conditions (adaptation and pulp density) using the indigenous acidophilic bacteria collected from acid mine drainage in Go-seong and Yeon-hwa, Korea. We conducted the batch experiments at the influences of parameters, such as the adaptation of bacteria and pulp density of the mine waste. In the adaptation case, the value of pH in 1'st adaptation bacteria sample exhibited lower than in 2'nd adaptation bacteria sample. And the content of both Cu and Zn at 1'st adaptation bacteria sample appeared lower than at 2'nd adaptation bacteria sample. In the SEM analysis, the rod-shaped bacteria with 1μm in length were observed on the filter paper (pore size - 0.45μm). The results of pulp density experiments revealed that the content of both Cu and Zn increased with increasing pulp density, since the increment of pulp density resulted in the enhancement of bioleaching capacity.

  3. Characterization of Bacteria Isolation of Bacteria from Pinyon Rhizosphere,

    Science.gov (United States)

    2016-01-01

    Two hundred and fifty bacterial strains were isolated from pinyon rhizosphere and screened for biosurfactants production. Among them, six bacterial strains were selected for their potential to produce biosurfactants using two low cost wastes, crude glycerol and lactoserum, as raw material. Both wastes were useful for producing biosurfactants because of their high content in fat and carbohydrates. The six strains were identified by 16S rDNA with an identity percentage higher than 95%, three strains belonged to Enterobacter sp., Pseudomonas aeruginosa, Bacillus pumilus and Rhizobium sp. All strains assayed were able to grow and showed halos around the colonies as evidence of biosurfactants production on Cetyl Trimethyl Ammonium Bromide agar with crude glycerol and lactoserum as substrate. In a mineral salt liquid medium enriched with both wastes, the biosurfactants were produced and collected from free cell medium after 72 h incubation. The biosurfactants produced reduced the surface tension from 69 to 30 mN/m with an emulsification index of diesel at approximately 60%. The results suggest that biosurfactants produced by rhizosphere bacteria from pinyon have promising environmental applications.

  4. Characterization of (per)chlorate-reducing bacteria

    NARCIS (Netherlands)

    Wolterink, A.F.W.M.

    2004-01-01

    Some bacteria can use (per)chlorateas terminal electron acceptor for growth. These bacteria convert perchlorate via chlorate and chlorite into chloride and molecular oxygen. Oxygen formation in microbial respiration is unique. In this study two chlorate-reducing strains

  5. Rapid methods for detection of bacteria

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Andersen, B.Ø.; Miller, M.

    2006-01-01

    Traditional methods for detection of bacteria in drinking water e.g. Heterotrophic Plate Counts (HPC) or Most Probable Number (MNP) take 48-72 hours to give the result. New rapid methods for detection of bacteria are needed to protect the consumers against contaminations. Two rapid methods...

  6. Rock-degrading endophytic bacteria in cacti

    Science.gov (United States)

    M. Esther Puente; Ching Y. Li; Yoav Bashan

    2009-01-01

    A plant-bacterium association of the cardon cactus (Pachycereus pringlei) and endophytic bacteria promotes establishment of seedlings and growth on igneous rocks without soil. These bacteria weather several rock types and minerals, unbind significant amounts of useful minerals for plants from the rocks, fix in vitro N2. produce...

  7. Comparative Genomics of Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Ussery, David; Davenport, C; Tümmler, B

    2010-01-01

    Eleven completely sequenced Chlorobi genomes were compared in oligonucleotide usage, gene contents, and synteny. The green sulfur bacteria (GSB) are equipped with a core genome that sustains their anoxygenic phototrophic lifestyle by photosynthesis, sulfur oxidation, and CO(2) fixation. Whole...... weight of 10(6), and are probably instrumental for the bacteria to generate their own intimate (micro)environment....

  8. Analyzing Arthropods for the Presence of Bacteria

    OpenAIRE

    Andrews, Elizabeth S.

    2013-01-01

    Bacteria within arthropods can be identified using culture-independent methods. This unit describes protocols for surface sterilization of arthropods, DNA extraction of whole bodies and tissues, touchdown PCR amplification using 16S rDNA general bacteria primers and profiling the bacterial community using denaturing gradient gel electrophoresis.

  9. Resuscitation effects of catalase on airborne bacteria.

    OpenAIRE

    Marthi, B; Shaffer, B T; Lighthart, B; Ganio, L

    1991-01-01

    Catalase incorporation into enumeration media caused a significant increase (greater than 63%) in the colony-forming abilities of airborne bacteria. Incubation for 30 to 60 min of airborne bacteria in collection fluid containing catalase caused a greater than 95% increase in colony-forming ability. However, catalase did not have any effects on enumeration at high relative humidities (80 to 90%).

  10. Catabolism of lysine by mixed rumen bacteria

    International Nuclear Information System (INIS)

    Onodera, Ryoji; Kandatsu, Makoto.

    1975-01-01

    Metabolites arising from the catabolism of lysine by the mixed rumen bacteria were chromatographically examined by using radioactive lysine. After 6 hr incubation, 241 nmole/ml of lysine was decomposed to give ether-soluble substances and CO 2 by the bacteria and 90 nmole/ml of lysine was incorporated unchanged into the bacteria. delta-Aminovalerate, cadaverine or pipecolate did not seem to be produced from lysine even after incubation of the bacteria with addition of those three amino compounds to trap besides lysine and radioactive lysine. Most of the ether-soluble substances produced from radioactive lysine was volatile fatty acids (VFAs). Fractionation of VFAs revealed that the peaks of butyric and acetic acids coincided with the strong radioactive peaks. Small amounts of radioactivities were detected in propionic acid peak and a peak assumed to be caproic acid. The rumen bacteria appeared to decompose much larger amounts of lysine than the rumen ciliate protozoa did. (auth.)

  11. Biodiversity of Bacteria Isolated from Different Soils

    Directory of Open Access Journals (Sweden)

    Fatma YAMAN

    2017-01-01

    Full Text Available The aim of this study was to determine the biodiversity of PHB producing bacteria isolated from soils where fruit and vegetable are cultivated (onion, grape, olive, mulberry and plum in Aydın providence. Morphological, cultural, biochemical, and molecular methods were used for bacteria identification. These isolated bacteria were identified by 16S rRNA sequencing and using BLAST. The following bacteria Bacillus thuringiensis (6, Bacillus cereus (8, Bacillus anthrachis (1, Bacillus circulans (1, Bacillus weihenstephanensis (1, Pseudomonas putida (1, Azotobacter chroococcum (1, Brevibacterium frigoritolerans (1, Burkholderia sp. (1, Staphylococcus epidermidis (1, Streptomyces exfoliatus (1, Variovorax paradoxus (1 were found. The Maximum Likelihood method was used to produce a molecular phylogenetic analysis and a phylogenetic tree was constructed. These bacteria can produce polyhydroxybutyrate (PHB which is an organic polymer with commercial potential as a biodegradable thermoplastic. PHB can be used instead of petrol derivated non-degradable plastics. For this reason, PHB producing microorganisms are substantial in industry.

  12. HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

    2006-08-15

    Fate of benzene ethylbenzene toluene xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted petroleum hydrocarbon contaminated soils. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. Biodegradation was measured using each organism individually and in combination. Both bacteria were shown to degrade each of the BTEX compounds. Alcaligenes piechaudii biodegraded BTEXs more efficiently while mixed with BP-20 and individually. Biosurfactant production was observed by culture techniques. In addition 3-hydroxy fatty acids, important in biosurfactant production, was observed by FAME analysis. In the all experiments toluene and m+p- xylenes were better growth substrates for both bacteria than the other BTEX compounds. In addition, the test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbons (BTEX) pollution increase biodegradation through the action by biosurfactants.

  13. Coryneform bacteria associated with canine otitis externa

    DEFF Research Database (Denmark)

    Aalbæk, Bent; Bemis, David A.; Schjærff, Mette

    2010-01-01

    This study aims to investigate the occurrence of coryneform bacteria in canine otitis externa. A combined case series and case-control study was carried out to improve the current knowledge on frequency and clinical significance of coryneform bacteria in samples from canine otitis externa. A total...... of 16 cases of otitis externa with involvement of coryneform bacteria were recorded at two referral veterinary hospitals in Denmark and the US, respectively. Coryneform bacteria were identified by partial 16S rRNA gene sequencing. Corynebacterium auriscanis was the most common coryneform species (10...... cases). Small colony variants of this species were also observed. Other coryneform isolates were identified as Corynebacterium amycolatum (3 cases), Corynebacterium freneyi (2 cases) and an Arcanobacterium-like species (1 case). The coryneform bacteria were in all cases isolated together with other...

  14. Type VI Secretion System Toxins Horizontally Shared between Marine Bacteria.

    Directory of Open Access Journals (Sweden)

    Dor Salomon

    2015-08-01

    Full Text Available The type VI secretion system (T6SS is a widespread protein secretion apparatus used by Gram-negative bacteria to deliver toxic effector proteins into adjacent bacterial or host cells. Here, we uncovered a role in interbacterial competition for the two T6SSs encoded by the marine pathogen Vibrio alginolyticus. Using comparative proteomics and genetics, we identified their effector repertoires. In addition to the previously described effector V12G01_02265, we identified three new effectors secreted by T6SS1, indicating that the T6SS1 secretes at least four antibacterial effectors, of which three are members of the MIX-effector class. We also showed that the T6SS2 secretes at least three antibacterial effectors. Our findings revealed that many MIX-effectors belonging to clan V are "orphan" effectors that neighbor mobile elements and are shared between marine bacteria via horizontal gene transfer. We demonstrated that a MIX V-effector from V. alginolyticus is a functional T6SS effector when ectopically expressed in another Vibrio species. We propose that mobile MIX V-effectors serve as an environmental reservoir of T6SS effectors that are shared and used to diversify antibacterial toxin repertoires in marine bacteria, resulting in enhanced competitive fitness.

  15. Effect of americium-241 on luminous bacteria. Role of peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrova, M., E-mail: maka-alexandrova@rambler.r [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Rozhko, T. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Vydryakova, G. [Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation); Kudryasheva, N. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation)

    2011-04-15

    The effect of americium-241 ({sup 241}Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of {sup 241}Am in nutrient media (0.16-6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 {sup o}C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the {sup 241}Am is discussed. The effect of {sup 241}Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in {sup 241}Am solutions was demonstrated; and the similarity of {sup 241}Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions. - Highlights: {yields} Am-241 in water solutions (A = 0.16-6.7 kBq/L) suppresses bacterial growth.{yields} Am-241 (A = 0.16-6.7 kBq/L) stimulate bacterial luminescence. {yields} Peroxides, secondary radiolysis products, cause increase of bacterial luminescence.

  16. Growth of Chlorella vulgaris and associated bacteria in photobioreactors

    Science.gov (United States)

    Lakaniemi, Aino‐Maija; Intihar, Veera M.; Tuovinen, Olli H.; Puhakka, Jaakko A.

    2012-01-01

    Summary The aim of this study was to test three flat plate photobioreactor configurations for growth of Chlorella vulgaris under non‐axenic conditions and to characterize and quantify associated bacterial communities. The photobioreactor cultivations were conducted using tap water‐based media to introduce background bacterial population. Growth of algae was monitored over time with three independent methods. Additionally, the quantity and quality of eukaryotes and bacteria were analysed using culture‐independent molecular tools based on denaturing gradient gel electrophoresis (PCR‐DGGE) and quantitative polymerase chain reaction (QPCR). Static mixers used in the flat plate photobioreactors did not generally enhance the growth at the low light intensities used. The maximum biomass concentration and maximum specific growth rate were 1.0 g l−1 and 2.0 day−1 respectively. Bacterial growth as determined by QPCR was associated with the growth of C. vulgaris. Based on PCR‐DGGE, bacteria in the cultures mainly originated from the tap water. Bacterial community profiles were diverse but reproducible in all flat plate cultures. Most prominent bacteria in the C. vulgaris cultures belonged to the class Alphaproteobacteria and especially to the genus Sphingomonas. Analysis of the diversity of non‐photosynthetic microorganisms in algal mass cultures can provide useful information on the public health aspects and unravel community interactions. PMID:21936882

  17. [Unique properties of highly radioresistant bacteria].

    Science.gov (United States)

    Romanovskaia, V A; Rokitko, P V; Malashenko, Iu R

    2000-01-01

    In connection with the Chernobyl Nuclear Power Plant (ChNPP) accident and the negative ecological after-effects for biota in this zone the interest has arisen to radioresistant bacteria, as to the most dynamic model of the given ecosystem, and to mechanisms which provide resistance of bacteria to ionizing radiation. The analysis of published data has shown that the radioresistant bacteria are not interrelated taxonomically and phylogenetically. The extreme radioresistant bacteria are represented by the Deinococcus species, which form a group phylogenetically close to the line Thermus-Meiothermus. Other radioresistant bacteria are the representatives of the genera Rubrobacter, Methylobacterium, Kocuria, Bacillus and some archebacteria. Data on natural habitats, of radioresistant bacteria are not numerous. In a number of cases it is difficult to distinguish their natural habitats, as they were isolated from the samples which were previously exposed to X-ray or gamma-irradiation, or from the ecosystems with the naturally raised radioactivity. To understand the strategy of survival of radioresistant bacteria, we briefly reviewed the mechanism of action of various species of radiation on cells and macromolecules; physiological signs of the cell damage caused by radiation; mechanisms eliminating (repairing) these damages. More details on mechanisms of the DNA repair in D. radiodurans are described. The extreme resistance of D. radiodurans to the DNA damaging factors is defined by 1) repair mechanisms which fundamentally differ from those in other procaryotes; 2) ability to increase the efficiency of a standard set of the DNA repairing proteins. Literary and own data on the effect of radiation on survival of various groups of bacteria in natural ecosystems are summarized. The ecological consequences of the ChNPP accident for soil bacteria in this region were estimated. The reduction of the number of soil bacteria and recession of microbial diversity under the effect of

  18. Comparative cytotoxicity of periodontal bacteria

    International Nuclear Information System (INIS)

    Stevens, R.H.; Hammond, B.F.

    1988-01-01

    The direct cytotoxicity of sonic extracts (SE) from nine periodontal bacteria for human gingival fibroblasts (HGF) was compared. Equivalent dosages (in terms of protein concentration) of SE were used to challenge HGF cultures. The cytotoxic potential of each SE was assessed by its ability to (1) inhibit HGF proliferation, as measured by direct cell counts; (2) inhibit 3H-thymidine incorporation in HGF cultures; or (3) cause morphological alterations of the cells in challenged cultures. The highest concentration (500 micrograms SE protein/ml) of any of the SEs used to challenge the cells was found to be markedly inhibitory to the HGFs by all three of the criteria of cytotoxicity. At the lowest dosage tested (50 micrograms SE protein/ml); only SE from Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Fusobacterium nucleatum caused a significant effect (greater than 90% inhibition or overt morphological abnormalities) in the HGFs as determined by any of the criteria employed. SE from Capnocytophaga sputigena, Eikenella corrodens, or Wolinella recta also inhibited cell proliferation and thymidine incorporation at this dosage; however, the degree of inhibition (5-50%) was consistently, clearly less than that of the first group of three organisms named above. The SE of the three other organisms tested (Actinomyces odontolyticus, Bacteroides intermedius, and Streptococcus sanguis) had little or no effect (0-10% inhibition) at this concentration. The data suggest that the outcome of the interaction between bacterial components and normal resident cells of the periodontium is, at least in part, a function of the bacterial species

  19. Tape Cassette Bacteria Detection System

    Science.gov (United States)

    1973-01-01

    The design, fabrication, and testing of an automatic bacteria detection system with a zero-g capability and based on the filter-capsule approach is described. This system is intended for monitoring the sterility of regenerated water in a spacecraft. The principle of detection is based on measuring the increase in chemiluminescence produced by the action of bacterial porphyrins (i.e., catalase, cytochromes, etc.) on a luminol-hydrogen peroxide mixture. Since viable as well as nonviable organisms initiate this luminescence, viable organisms are detected by comparing the signal of an incubated water sample with an unincubated control. Higher signals for the former indicate the presence of viable organisms. System features include disposable sealed sterile capsules, each containing a filter membrane, for processing discrete water samples and a tape transport for moving these capsules through a processing sequence which involves sample concentration, nutrient addition, incubation, a 4 Molar Urea wash and reaction with luminol-hydrogen peroxide in front of a photomultiplier tube. Liquids are introduced by means of a syringe needle which pierces a rubber septum contained in the wall of the capsule. Detection thresholds obtained with this unit towards E. coli and S. marcescens assuming a 400 ml water sample are indicated.

  20. Antioxidant Properties of Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2017-05-01

    Full Text Available Oxidative stress defines a condition in which the prooxidant–antioxidant balance in the cell is disturbed, resulting in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells’ viability. Probiotics have been known for many beneficial health effects, and the consumption of probiotics alone or in food shows that strain-specific probiotics can present antioxidant activity and reduce damages caused by oxidation. However, the oxidation-resistant ability of probiotics, especially the underling mechanisms, is not properly understood. In this view, there is interest to figure out the antioxidant property of probiotics and summarize the mode of action of probiotic bacteria in antioxidation. Therefore, in the present paper, the antioxidant mechanisms of probiotics have been reviewed in terms of their ability to improve the antioxidant system and their ability to decrease radical generation. Since in recent years, oxidative stress has been associated with an altered gut microbiota, the effects of probiotics on intestinal flora composition are also elaborated.

  1. The role of sulfur-oxidizing bacteria Thiobacillus thiooxidans in pyrite weathering

    International Nuclear Information System (INIS)

    Sasaki, K.; Tsunekawa, M.; Ohtsuka, T.; Konno, H.

    1998-01-01

    The paper investigates the role of the sulfur-oxidizing bacteria Thiobacillus thiooxidans in pyrite weathering in order to clarify the effects of the bacteria on the dissolution behavior of pyrite and the formation of secondary minerals using Raman spectroscopy and powder X-ray diffraction (XRD) in addition to solution analysis. It was found that T. thiooxidans, when present with the iron-oxidizing bacteria Thiobacillus ferrooxidans, enhanced the dissolution of Fe and S species for pyrite, whereas T. thiooxidans alone did not oxidize pyrite. Enhancement of the consumption of elemental sulfur and regeneration of Fe(II) ions were also observed with T. thiooxidans together with T. ferrooxidans, while this did not occur with T. ferrooxidans alone

  2. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Alix M Denoncourt

    2014-05-01

    Full Text Available Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.

  3. Enhancing the biological nitrogen fixation of leguminous crops ...

    African Journals Online (AJOL)

    Legumes have the ability to establish a symbiotic interaction with soil bacteria, collectively termed as rhizobia. These bacteria can enhance growth and development of associated crops by transferring atmospheric nitrogen into a form that is available for plant growth or by improving nutrient uptake through modulation of ...

  4. Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria.

    Science.gov (United States)

    Troxell, Bryan; Hassan, Hosni M

    2013-01-01

    In the ancient anaerobic environment, ferrous iron (Fe(2+)) was one of the first metal cofactors. Oxygenation of the ancient world challenged bacteria to acquire the insoluble ferric iron (Fe(3+)) and later to defend against reactive oxygen species (ROS) generated by the Fenton chemistry. To acquire Fe(3+), bacteria produce low-molecular weight compounds, known as siderophores, which have extremely high affinity for Fe(3+). However, during infection the host restricts iron from pathogens by producing iron- and siderophore-chelating proteins, by exporting iron from intracellular pathogen-containing compartments, and by limiting absorption of dietary iron. Ferric Uptake Regulator (Fur) is a transcription factor which utilizes Fe(2+) as a corepressor and represses siderophore synthesis in pathogens. Fur, directly or indirectly, controls expression of enzymes that protect against ROS damage. Thus, the challenges of iron homeostasis and defense against ROS are addressed via Fur. Although the role of Fur as a repressor is well-documented, emerging evidence demonstrates that Fur can function as an activator. Fur activation can occur through three distinct mechanisms (1) indirectly via small RNAs, (2) binding at cis regulatory elements that enhance recruitment of the RNA polymerase holoenzyme (RNAP), and (3) functioning as an antirepressor by removing or blocking DNA binding of a repressor of transcription. In addition, Fur homologs control defense against peroxide stress (PerR) and control uptake of other metals such as zinc (Zur) and manganese (Mur) in pathogenic bacteria. Fur family members are important for virulence within bacterial pathogens since mutants of fur, perR, or zur exhibit reduced virulence within numerous animal and plant models of infection. This review focuses on the breadth of Fur regulation in pathogenic bacteria.

  5. Endophytic colonization of plant roots by nitrogen-fixing bacteria

    International Nuclear Information System (INIS)

    Cocking, Edward C.

    2001-01-01

    Nitrogen-fixing bacteria are able to enter into roots from the rhizosphere, particularly at the base of emerging lateral roots, between epidermal cells and through root hairs. In the rhizosphere growing root hairs play an important role in symbiotic recognition in legume crops. Nodulated legumes in endosymbiosis with rhizobia are amongst the most prominent nitrogen-fixing systems in agriculture. The inoculation of non-legumes, especially cereals, with various non-rhizobial diazotrophic bacteria has been undertaken with the expectation that they would establish themselves intercellularly within the root system, fixing nitrogen endophytic ally and providing combined nitrogen for enhanced crop production. However, in most instances bacteria colonize only the surface of the roots and remain vulnerable to competition from other rhizosphere micro-organisms, even when the nitrogen-fixing bacteria are endophytic, benefits to the plant may result from better uptake of soil nutrients rather than from endophytic nitrogen fixation. Azorhizobium caulinodans is known to enter the root system of cereals, other nonlegume crops and Arabidopsis, by intercellular invasion between epidermal cells and to internally colonize the plant intercellularly, including the xylem. This raises the possibility that xylem colonization might provide a nonnodular niche for endosymbiotic nitrogen fixation in rice, wheat, maize, sorghum and other non-legume crops. A particularly interesting, naturally occurring, non-qodular xylem colonising endophytic diazotrophic interaction with evidence for endophytic nitrogen fixation is that of Gluconacetobacter diazotrophicus in sugarcane. Could this beneficial endophytic colonization of sugarcane by G. diazotrophicus be extended to other members of the Gramineae, including the major cereals, and to other major non-legume crops of the World? (author)

  6. Folate Production by Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Stefano Raimondi

    2011-01-01

    Full Text Available Probiotic bacteria, mostly belonging to the genera Lactobacillus and Bifidobacterium, confer a number of health benefits to the host, including vitamin production. With the aim to produce folate-enriched fermented products and/or develop probiotic supplements that accomplish folate biosynthesis in vivo within the colon, bifidobacteria and lactobacilli have been extensively studied for their capability to produce this vitamin. On the basis of physiological studies and genome analysis, wild-type lactobacilli cannot synthesize folate, generally require it for growth, and provide a negative contribution to folate levels in fermented dairy products. Lactobacillus plantarum constitutes an exception among lactobacilli, since it is capable of folate production in presence of para-aminobenzoic acid (pABA and deserves to be used in animal trials to validate its ability to produce the vitamin in vivo. On the other hand, several folate-producing strains have been selected within the genus Bifidobacterium, with a great variability in the extent of vitamin released in the medium. Most of them belong to the species B. adolescentis and B. pseudocatenulatum, but few folate producing strains are found in the other species as well. Rats fed a probiotic formulation of folate-producing bifidobacteria exhibited increased plasma folate level, confirming that the vitamin is produced in vivo and absorbed. In a human trial, the same supplement raised folate concentration in feces. The use of folate-producing probiotic strains can be regarded as a new perspective in the specific use of probiotics. They could more efficiently confer protection against inflammation and cancer, both exerting the beneficial effects of probiotics and preventing the folate deficiency that is associated with premalignant changes in the colonic epithelia.

  7. Magnetotactic Bacteria from Extreme Environments

    Directory of Open Access Journals (Sweden)

    Christopher T. Lefèvre

    2013-03-01

    Full Text Available Magnetotactic bacteria (MTB represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4 or greigite (Fe3S4 and cause cells to align along the Earth’s geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic–anoxic interface (OAI in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.

  8. Fermentative Bacteria Influence the Competition between Denitrifiers and DNRA Bacteria

    Directory of Open Access Journals (Sweden)

    Eveline M. van den Berg

    2017-09-01

    results of this study clearly show that not only the ratio of available substrates, but also the nature of the electron donor influences the outcome of competition between DNRA and denitrification. Apparently, fermentative bacteria are competitive for the electron donor and thereby alter the ratio of available substrates for nitrate reduction.

  9. The Microworld of Marine-Bacteria

    DEFF Research Database (Denmark)

    JØRGENSEN, BB

    1995-01-01

    Microsensor studies show that the marine environment in the size scale of bacteria is physically and chemically very different from the macroenvironment. The microbial world of the sediment-water interface is thus dominated by water viscosity and steep diffusion gradients. Because of the diverse...... metabolism types, bacteria in the mostly anoxic sea floor play an important role in the major element cycles of the ocean. The communities of giant, filamentous sulfur bacteria that live in the deep-sea hydrothermal vents or along the Pacific coast of South America are presented here as examples....

  10. Labelling of bacteria with indium chelates

    International Nuclear Information System (INIS)

    Kleinert, P.; Pfister, W.; Endert, G.; Sproessig, M.

    1985-01-01

    The indium chelates were prepared by reaction of radioactive indiumchloride with 10 μg oxine, 15 μg tropolone and 3 mg acetylacetone, resp. The formed chelates have been incubated with 10 9 germs/ml for 5 minutes, with labelling outputs from 90 to 95%. Both gram-positive (Streptococcus, Staphylococcus) and gram-negative bacteria (Escherichia coli) can be labelled. The reproductive capacity of the bacteria was not impaired. The application of indium labelled bacteria allows to show the distribution of microorganisms within the living organism and to investigate problems of bacterial adherence. (author)

  11. Mortality of fecal bacteria in seawater

    International Nuclear Information System (INIS)

    Garcia-Lara, J.; Menon, P.; Servais, P.; Billen, G.

    1991-01-01

    The authors propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloracetic acid-insoluble fraction in water samples to which [ 3 H]thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, they found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate

  12. Pu sorption to activated conglomerate anaerobic bacteria

    International Nuclear Information System (INIS)

    Sasaki, Takayuki; Kudo, Akira

    2001-01-01

    The sorption of Pu to the anaerobic bacteria activated under specific conditions of temperature, pH and depleted nutrients after long dormant period was investigated. After 4 h at neutral pH, the distribution coefficient (K d ) between bacteria and aqueous phase at 308 and 278 K had around 10 3 to 10 4 . After over 5 days, however, the K d at only 308 K had increased to over 10 5 . Sterilized (dead) and dormant anaerobic bacteria adsorbed Pu to the same extent. (author)

  13. Bacteria Culture Test: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/bacteriaculturetest.html Bacteria Culture Test To use the sharing features on this page, please enable JavaScript. What is a Bacteria Culture Test? Bacteria are a large group of ...

  14. Flow cytometry, fluorescent probes, and flashing bacteria

    NARCIS (Netherlands)

    Bunthof, C.J.

    2002-01-01


    Key words: fluorescent probes, flow cytometry, CSLM, viability, survival, microbial physiology, lactic acid bacteria, Lactococcus lactis , Lactobacillus plantarum , cheese, milk,

  15. Effect of leukocyte hydrolases on bacteria

    International Nuclear Information System (INIS)

    Cohen, D.; Michel, J.; Ferne, M.; Bergner-Rabinowitz, S.; Ginsburg, I.

    1979-01-01

    Leukocyte extracts, trypsin, and lysozyme are all capable of releasing the bulk of the LPS from S. typhi, S. typhimurium, and E. coli. Bacteria which have been killed by heat, ultraviolet irradiation, or by a variety of metabolic inhibitors and antibiotics which affect protein, DNA, RNA, and cell wall synthesis no longer yield soluble LPS following treatment with the releasing agents. On the other hand, bacteria which are resistant to certain of the antibiotics yield nearly the full amount of soluble LPS following treatment, suggesting that certain heatabile endogenous metabolic pathways collaborate with the releasing agents in the release of LPS from the bacteria. It is suggested that some of the beneficial effects of antibiotics on infections with gram-negative bacteria may be the prevention of massive release of endotoxin by leukocyte enzymes in inflammatory sites

  16. Systemic resistance induced by rhizosphere bacteria

    NARCIS (Netherlands)

    Loon, L.C. van; Bakker, P.A.H.M.; Pieterse, C.M.J.

    1998-01-01

    Nonpathogenic rhizobacteria can induce a systemic resistance in plants that is phenotypically similar to pathogen-induced systemic acquired resistance (SAR). Rhizobacteria-mediated induced systemic resistance (ISR) has been demonstrated against fungi, bacteria, and viruses in Arabidopsis, bean,

  17. Lactic acid bacteria: microbiological and functional aspects

    National Research Council Canada - National Science Library

    Lahtinen, Sampo

    2012-01-01

    "Updated with the substantial progress made in lactic acid and bacteria research since the third edition, this fourth volume discusses improved insights in genetics and new molecular biological techniques...

  18. Comparative genomics of the lactic acid bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; Karamychev, V.; Polouchine, N.; Shakhova, V.; Grigoriev, I.; Lou, Y.; Rokhsar, D.; Lucas, S.; Huang, K.; Goodstein, D. M.; Hawkins, T.; Plengvidhya, V.; Welker, D.; Hughes, J.; Goh, Y.; Benson, A.; Baldwin, K.; Lee, J. -H.; Diaz-Muniz, I.; Dosti, B.; Smeianov, V; Wechter, W.; Barabote, R.; Lorca, G.; Altermann, E.; Barrangou, R.; Ganesan, B.; Xie, Y.; Rawsthorne, H.; Tamir, D.; Parker, C.; Breidt, F.; Broadbent, J.; Hutkins, R.; O' Sullivan, D.; Steele, J.; Unlu, G.; Saier, M.; Klaenhammer, T.; Richardson, P.; Kozyavkin, S.; Weimer, B.; Mills, D.

    2006-06-01

    Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

  19. Bacteria-mediated bisphenol A degradation.

    Science.gov (United States)

    Zhang, Weiwei; Yin, Kun; Chen, Lingxin

    2013-07-01

    Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred.

  20. Abundance, viability and culturability of Antarctic bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; DeSouza, M.J.B.D.; Nair, S.; Chandramohan, D.

    The viability of total number of bacteria decide the mineralisation rate in any ecosystem and ultimately the fertility of the region. This study aims at establishing the extent of viability in the standing stock of the Antarctic bacterial population...

  1. Interactions between phototrophic bacteria in marine sediments

    NARCIS (Netherlands)

    de Wit, Rutger

    1989-01-01

    Phototrophic bacteria are the most consicious organisms occuring in laminated microbial sediment ecosystems (microbial mats). In the Waddensea area ecosystems consisting of a toplayer of the cyanobacterium Microleus chthonoplastes overlying a red layer of the purple sulfur bacterium Thiocapsa

  2. Insights into the Synergistic Effect of Fungi and Bacteria for Reactive Red Decolorization

    Directory of Open Access Journals (Sweden)

    Dandan Zhou

    2014-01-01

    Full Text Available Bacterial contamination is a prevalent problem in fungal dye wastewater decolorization that prevents the development of this technology in practical engineering. New insight into the relationship between fungi and bacteria is given in terms of settleability, bioadsorption, and biodegradation, which all confirm their synergistic effect. Sterilization is implied to be not the only mechanism for fungi decolorization. When the fungi and bacteria isolated from the activated sludge were cocultured, fungi removed more than 70% of the reactive red through sole bioadsorption in 5 min and enhanced the settleability of the bacteria group from 7.7 to 18.4 in the aggregation index. Subsequently, the bacteria played a more significant role in dye biodegradation according to the ultraviolet-visible spectrum analysis. They further enhanced the decolorization efficiency to over 80% when cocultured with fungi. Therefore, the advanced bioadsorption and settleability of fungi, combined with the good dye biodegradation ability of bacteria, results in the synergistic effect of the coculture microorganisms.

  3. Molecular genetic studies on obligate anaerobic bacteria

    International Nuclear Information System (INIS)

    Woods, D.R.

    1982-01-01

    Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

  4. Ecology: Electrical Cable Bacteria Save Marine Life

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter

    2016-01-01

    Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide.......Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide....

  5. Occurrence of diazotrophic bacteria in Araucaria angustifolia

    OpenAIRE

    Neroni,Rafaela de Fátima; Cardoso,Elke Jurandy Bran Nogueira

    2007-01-01

    Araucaria angustifolia is an environmentally threatened tree and the whole biota of the Araucaria Forest should be investigated with the aim of its preservation. Diazotrophic bacteria are extremely important for the maintenance of ecosystems, but they have never been studied in Araucaria Forests. In this study, diazotrophic bacteria were isolated from Araucaria roots and soil, when grown in semi-specific, semi-solid media. The diazotrophic character of some recovered isolates could be confirm...

  6. [Teichoic acids from lactic acid bacteria].

    Science.gov (United States)

    Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

    2012-01-01

    The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

  7. Plant probiotic bacteria Bacillus and Paraburkholderia improve growth, yield and content of antioxidants in strawberry fruit.

    Science.gov (United States)

    Rahman, Mosaddiqur; Sabir, Abdullah As; Mukta, Julakha Akter; Khan, Md Mohibul Alam; Mohi-Ud-Din, Mohammed; Miah, Md Giashuddin; Rahman, Mahfuzur; Islam, M Tofazzal

    2018-02-06

    Strawberry is an excellent source of natural antioxidants with high capacity of scavenging free radicals. This study evaluated the effects of two plant probiotic bacteria, Bacillus amylolequefaciens BChi1 and Paraburkholderia fungorum BRRh-4 on growth, fruit yield and antioxidant contents in strawberry fruits. Root dipping of seedlings (plug plants) followed by spray applications of both probiotic bacteria in the field on foliage significantly increased fruit yield (up to 48%) over non-treated control. Enhanced fruit yield likely to be linked with higher root and shoot growth, individual and total fruit weight/plant and production of phytohormone by the probiotic bacteria applied on plants. Interestingly, the fruits from plants inoculated with the isolates BChi1 and BRRh-4 had significantly higher contents of phenolics, carotenoids, flavonoids and anthocyanins over non-treated control. Total antioxidant activities were also significantly higher (p < 0.05) in fruits of strawberry plants treated with both probiotic bacteria. To the best of our knowledge, this is the first report of significant improvement of both yield and quality of strawberry fruits by the application of plant probiotic bacteria BChi1 and BRRh-4 in a field condition. Further study is needed to elucidate underlying mechanism of growth and quality improvement of strawberry fruits by probiotic bacteria.

  8. Engineering nanoparticle-coated bacteria as oral DNA vaccines for cancer immunotherapy.

    Science.gov (United States)

    Hu, Qinglian; Wu, Min; Fang, Chun; Cheng, Changyong; Zhao, Mengmeng; Fang, Weihuan; Chu, Paul K; Ping, Yuan; Tang, Guping

    2015-04-08

    Live attenuated bacteria are of increasing importance in biotechnology and medicine in the emerging field of cancer immunotherapy. Oral DNA vaccination mediated by live attenuated bacteria often suffers from low infection efficiency due to various biological barriers during the infection process. To this end, we herein report, for the first time, a new strategy to engineer cationic nanoparticle-coated bacterial vectors that can efficiently deliver oral DNA vaccine for efficacious cancer immunotherapy. By coating live attenuated bacteria with synthetic nanoparticles self-assembled from cationic polymers and plasmid DNA, the protective nanoparticle coating layer is able to facilitate bacteria to effectively escape phagosomes, significantly enhance the acid tolerance of bacteria in stomach and intestines, and greatly promote dissemination of bacteria into blood circulation after oral administration. Most importantly, oral delivery of DNA vaccines encoding autologous vascular endothelial growth factor receptor 2 (VEGFR2) by this hybrid vector showed remarkable T cell activation and cytokine production. Successful inhibition of tumor growth was also achieved by efficient oral delivery of VEGFR2 with nanoparticle-coated bacterial vectors due to angiogenesis suppression in the tumor vasculature and tumor necrosis. This proof-of-concept work demonstrates that coating live bacterial cells with synthetic nanoparticles represents a promising strategy to engineer efficient and versatile DNA vaccines for the era of immunotherapy.

  9. Acid, bile, and heat tolerance of free and microencapsulated probiotic bacteria.

    Science.gov (United States)

    Ding, W K; Shah, N P

    2007-11-01

    Eight strains of probiotic bacteria, including Lactobacillus rhamnosus, Bifidobacterium longum, L. salivarius, L. plantarum, L. acidophilus, L. paracasei, B. lactis type Bl-O4, and B. lactis type Bi-07, were studied for their acid, bile, and heat tolerance. Microencapsulation in alginate matrix was used to enhance survival of the bacteria in acid and bile as well as a brief exposure to heat. Free probiotic organisms were used as a control. The acid tolerance of probiotic organisms was tested using HCl in MRS broth over a 2-h incubation period. Bile tolerance was tested using 2 types of bile salts, oxgall and taurocholic acid, over an 8-h incubation period. Heat tolerance was tested by exposing the probiotic organisms to 65 degrees C for up to 1 h. Results indicated microencapsulated probiotic bacteria survived better (P strains. At 30 min of heat treatment, microencapsulated probiotic bacteria survived with an average loss of only 4.17-log CFU/mL, compared to 6.74-log CFU/mL loss with free probiotic bacteria. However, after 1 h of heating both free and microencapsulated probiotic strains showed similar losses in viability. Overall microencapsulation improved the survival of probiotic bacteria when exposed to acidic conditions, bile salts, and mild heat treatment.

  10. Contribution of midgut bacteria to blood digestion and egg production in aedes aegypti (diptera: culicidae (L.

    Directory of Open Access Journals (Sweden)

    Pimenta Paulo FP

    2011-06-01

    Full Text Available Abstract Background The insect gut harbors a variety of microorganisms that probably exceed the number of cells in insects themselves. These microorganisms can live and multiply in the insect, contributing to digestion, nutrition, and development of their host. Recent studies have shown that midgut bacteria appear to strengthen the mosquito's immune system and indirectly enhance protection from invading pathogens. Nevertheless, the physiological significance of these bacteria for mosquitoes has not been established to date. In this study, oral administration of antibiotics was employed in order to examine the contribution of gut bacteria to blood digestion and fecundity in Aedes aegypti. Results The antibiotics carbenicillin, tetracycline, spectinomycin, gentamycin and kanamycin, were individually offered to female mosquitoes. Treatment of female mosquitoes with antibiotics affected the lysis of red blood cells (RBCs, retarded the digestion of blood proteins and reduced egg production. In addition, antibiotics did not affect the survival of mosquitoes. Mosquito fertility was restored in the second gonotrophic cycle after suspension of the antibiotic treatment, showing that the negative effects of antibiotics in blood digestion and egg production in the first gonotrophic cycle were reversible. Conclusions The reduction of bacteria affected RBC lysis, subsequently retarded protein digestion, deprived mosquito from essential nutrients and, finally, oocyte maturation was affected, resulting in the production of fewer viable eggs. These results indicate that Ae. aegypti and its midgut bacteria work in synergism to digest a blood meal. Our findings open new possibilities to investigate Ae. aegypti-associated bacteria as targets for mosquito control strategies.

  11. Motility Control of Bacteria-Actuated Biodegradable Polymeric Microstructures by Selective Adhesion Methods

    Directory of Open Access Journals (Sweden)

    Hyung Jung Yoo

    2014-11-01

    Full Text Available Certain bacteria have motility and can be made non-toxic, and using them for drug delivery has been proposed. For example, using bacteria with flagella motion in multiple spin actuators in drug delivery microrobots has been suggested. This paper investigates various adhesion enhancement methods for attaching bacteria on preferred surfaces of cubic polymeric microstructures to achieve the directional control of motion. Serratia marcescens which has an excellent swimming behavior and 50-μm sized cubic structures made of biodegradable poly-capro-lactone (PCL are used. Three treatment methods are investigated and compared to the untreated control case. The first method is retarding bacterial attachments by coating certain surfaces with bovine serum albumin (BSA which makes those surfaces anti-adherent to bacteria. The second and third methods are roughening the surfaces with X-ray irradiation and plasma respectively to purposely increase bacterial attachments on the roughened surfaces. The measured motilities of bacteria-tethered PCL microactuators are 1.40 μm/s for the BSA coating method, 0.82 μm/s for the X-ray irradiation, and 3.89 μm/s for the plasma treatment method. Therefore, among the methods investigated in the paper the plasma treatment method achieves the highest directionality control of bacteria motility.

  12. Mimicking Seawater For Culturing Marine Bacteria

    DEFF Research Database (Denmark)

    Rygaard, Anita Mac; Sonnenschein, Eva; Gram, Lone

    2015-01-01

    Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum as solidif......Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum...... as solidifying agents, and enumerated bacteria from seawater and algal exudates. We tested if culturability could be influenced by addition of quorum sensing signals (AHLs). All plates were incubated at 15°C. Bacterial counts (CFU/g) from algal exudates from brown algae were highest on media containing algal...... polymers. In general, bacteria isolated from algal exudates preferred more rich media than bacteria isolated from seawater. Overall, culturability ranged from 0.01 to 0.8% as compared to total cell count. Substitution of agar with gellan gum increased the culturability of seawater bacteria approximately...

  13. Antibiotic-resistant bacteria in drinking water.

    Science.gov (United States)

    Armstrong, J L; Shigeno, D S; Calomiris, J J; Seidler, R J

    1981-08-01

    We analyzed drinking water from seven communities for multiply antibiotic-resistant (MAR) bacteria (bacteria resistant to two or more antibiotics) and screened the MAR bacterial isolates obtained against five antibiotics by replica plating. Overall, 33.9% of 2,653 standard plate count bacteria from treated drinking waters were MAR. Two different raw water supplies for two communities carried MAR standard plate count bacteria at frequencies of 20.4 and 18.6%, whereas 36.7 and 67.8% of the standard plate count populations from sites within the respective distribution systems were MAR. Isolate identification revealed that MAR gram-positive cocci (Staphylococcus) and MAR gram-negative, nonfermentative rods (Pseudomonas, Alcaligenes, Moraxella-like group M, and Acinetobacter) were more common in drinking waters than in untreated source waters. Site-to-site variations in generic types and differences in the incidences of MAR organisms indicated that shedding of MAR bacteria living in pipelines may have contributed to the MAR populations in tap water. We conclude that the treatment of raw water and its subsequent distribution select for standard plate count bacteria exhibiting the MAR phenotype.

  14. Innovative Approaches Using Lichen Enriched Media to Improve Isolation and Culturability of Lichen Associated Bacteria.

    Science.gov (United States)

    Biosca, Elena G; Flores, Raquel; Santander, Ricardo D; Díez-Gil, José Luis; Barreno, Eva

    2016-01-01

    Lichens, self-supporting mutualistic associations between a fungal partner and one or more photosynthetic partners, also harbor non-photosynthetic bacteria. The diversity and contribution of these bacteria to the functioning of lichen symbiosis have recently begun to be studied, often by culture-independent techniques due to difficulties in their isolation and culture. However, culturing as yet unculturable lichenic bacteria is critical to unravel their potential functional roles in lichen symbiogenesis, to explore and exploit their biotechnological potential and for the description of new taxa. Our objective was to improve the recovery of lichen associated bacteria by developing novel isolation and culture approaches, initially using the lichen Pseudevernia furfuracea. We evaluated the effect of newly developed media enriched with novel lichen extracts, as well as the influence of thalli washing time and different disinfection and processing protocols of thalli. The developed methodology included: i) the use of lichen enriched media to mimic lichen nutrients, supplemented with the fungicide natamycin; ii) an extended washing of thalli to increase the recovery of ectolichenic bacteria, thus allowing the disinfection of thalli to be discarded, hence enhancing endolichenic bacteria recovery; and iii) the use of an antioxidant buffer to prevent or reduce oxidative stress during thalli disruption. The optimized methodology allowed significant increases in the number and diversity of culturable bacteria associated with P. furfuracea, and it was also successfully applied to the lichens Ramalina farinacea and Parmotrema pseudotinctorum. Furthermore, we provide, for the first time, data on the abundance of culturable ecto- and endolichenic bacteria that naturally colonize P. furfuracea, R. farinacea and P. pseudotinctorum, some of which were only able to grow on lichen enriched media. This innovative methodology is also applicable to other microorganisms inhabiting these

  15. Innovative Approaches Using Lichen Enriched Media to Improve Isolation and Culturability of Lichen Associated Bacteria

    Science.gov (United States)

    Biosca, Elena G.; Flores, Raquel; Santander, Ricardo D.; Díez-Gil, José Luis; Barreno, Eva

    2016-01-01

    Lichens, self-supporting mutualistic associations between a fungal partner and one or more photosynthetic partners, also harbor non-photosynthetic bacteria. The diversity and contribution of these bacteria to the functioning of lichen symbiosis have recently begun to be studied, often by culture-independent techniques due to difficulties in their isolation and culture. However, culturing as yet unculturable lichenic bacteria is critical to unravel their potential functional roles in lichen symbiogenesis, to explore and exploit their biotechnological potential and for the description of new taxa. Our objective was to improve the recovery of lichen associated bacteria by developing novel isolation and culture approaches, initially using the lichen Pseudevernia furfuracea. We evaluated the effect of newly developed media enriched with novel lichen extracts, as well as the influence of thalli washing time and different disinfection and processing protocols of thalli. The developed methodology included: i) the use of lichen enriched media to mimic lichen nutrients, supplemented with the fungicide natamycin; ii) an extended washing of thalli to increase the recovery of ectolichenic bacteria, thus allowing the disinfection of thalli to be discarded, hence enhancing endolichenic bacteria recovery; and iii) the use of an antioxidant buffer to prevent or reduce oxidative stress during thalli disruption. The optimized methodology allowed significant increases in the number and diversity of culturable bacteria associated with P. furfuracea, and it was also successfully applied to the lichens Ramalina farinacea and Parmotrema pseudotinctorum. Furthermore, we provide, for the first time, data on the abundance of culturable ecto- and endolichenic bacteria that naturally colonize P. furfuracea, R. farinacea and P. pseudotinctorum, some of which were only able to grow on lichen enriched media. This innovative methodology is also applicable to other microorganisms inhabiting these

  16. Nanotextile membranes for bacteria Escherichia coli capturing

    Directory of Open Access Journals (Sweden)

    Jaroslav Lev

    2010-01-01

    Full Text Available The article describes an experimental study dealing with the possibility of nanotextile materials usa­ge for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP. As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E. coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration.Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified.

  17. [Spectrum and susceptibility of preoperative conjunctival bacteria].

    Science.gov (United States)

    Fernández-Rubio, M E; Cuesta-Rodríguez, T; Urcelay-Segura, J L; Cortés-Valdés, C

    2013-12-01

    To describe the conjunctival bacterial spectrum of our patients undergoing intraocular surgery and their antibiotic sensitivity during the study period. A retrospective study of preoperative conjunctival culture of patients consecutively scheduled for intraocular surgery from 21 February 2011 to 1 April 2013. Specimens were directly seeded onto blood-agar and MacConkey-agar (aerobiosis incubation, 2 days), and on chocolate-agar (6% CO2 incubation, 7 days). The identified bacteria were divided into 3 groups according to their origin; the bacteria susceptibility tests were performed on those more pathogenic and on some of the less pathogenic when more than 5 colonies were isolated. The sensitivity of the exigent growing bacteria was obtained with disk diffusion technique, and for of the non-exigent bacteria by determining their minimum inhibitory concentration. The Epidat 3.1 program was used for statistical calculations. A total of 13,203 bacteria were identified in 6,051 cultures, with 88.7% being typical colonizers of conjunctiva (group 1), 8.8% typical of airways (group 2), and the remaining 2.5% of undetermined origin (group 3). 530 cultures (8.8%) were sterile. The sensitivity of group 1 was: 99% vancomycin, 95% rifampicin, 87% chloramphenicol, 76% tetracycline. Levels of co-trimoxazole, aminoglycosides, quinolones, β-lactams and macrolides decreased since 2007. The group 2 was very sensitive to chloramphenicol, cefuroxime, rifampicin, ciprofloxacin and amoxicillin/clavulanate. In group 3, to levofloxacin 93%, ciprofloxacin 89%, tobramycin 76%, but ceftazidime 53% and cefuroxime 29% decreased. None of the tested antibiotics could eradicate all possible conjunctival bacteria. Bacteria living permanently on the conjunctiva (group 1) have achieved higher resistance than the eventual colonizers. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  18. Magnetosome chain superstructure in uncultured magnetotactic bacteria

    International Nuclear Information System (INIS)

    Abraçado, Leida G; Farina, Marcos; Abreu, Fernanda; Keim, Carolina N; Lins, Ulysses; Campos, Andrea P C

    2010-01-01

    Magnetotactic bacteria produce magnetosomes, which are magnetic particles enveloped by biological membranes, in a highly controlled mineralization process. Magnetosomes are used to navigate in magnetic fields by a phenomenon called magnetotaxis. Two levels of organization and control are recognized in magnetosomes. First, magnetotactic bacteria create a spatially distinct environment within vesicles defined by their membranes. In the vesicles, the bacteria control the size, composition and purity of the mineral content of the magnetic particles. Unique crystal morphologies are produced in magnetosomes as a consequence of this bacterial control. Second, magnetotactic bacteria organize the magnetosomes in chains within the cell body. It has been shown in a particular case that the chains are positioned within the cell body in specific locations defined by filamentous cytoskeleton elements. Here, we describe an additional level of organization of the magnetosome chains in uncultured magnetotactic cocci found in marine and freshwater sediments. Electron microscopy analysis of the magnetosome chains using a goniometer showed that the magnetic crystals in both types of bacteria are not oriented at random along the crystal chain. Instead, the magnetosomes have specific orientations relative to the other magnetosomes in the chain. Each crystal is rotated either 60°, 180° or 300° relative to their neighbors along the chain axis, causing the overlapping of the (1 1 1) and (1-bar 1-bar 1-bar) capping faces of neighboring crystals. We suggest that genetic determinants that are not present or active in bacteria with magnetosomes randomly rotated within a chain must be present in bacteria that organize magnetosomes so precisely. This particular organization may also be used as an indicative biosignature of magnetosomes in the study of magnetofossils in the cases where this symmetry is observed

  19. Using Bacteria to Store Renewable Energy (Text Version) | News | NREL

    Science.gov (United States)

    Using Bacteria to Store Renewable Energy (Text Version) Using Bacteria to Store Renewable Energy is a text version of the video entitled "Using Bacteria to Store Renewable Energy." ; Bacteria from some of the Earth's harshest environments now have a new home at NREL. [A natural spring has

  20. Rapid diagnostics of the bacteria in air

    Energy Technology Data Exchange (ETDEWEB)

    Belov Nikolai, N. [ATECH KFT, Budapest (Hungary)

    2000-07-01

    Presence of the bacteria and viruses in the air is great problem now. Terrorists are going to use the bacteria weapon. Now biotechnology provides very cheap equipment ({approx} $500) for modification of the bacteria sorts. It may be used for receiving of new variants of the bacteriological weapon. And presence of one small bacteria aerosol generator in the international airport during several days will start the dangerous epidemic incidence the entire world. From another side - poor countries with hot and wet weather are continuously producing new and new dangerous bacteria. Every year epidemic waves of influence are going from China, India or Africa. And once up a time it will be epidemic explosive with fast lethal finish. Methods of estimation of the bio-aerosols in Air of City are very poor. Standard Bio-aerosol sampler has two conflicting demands. From one side the bio-sampler needs in great air volume of sample with great efficiency of separation of aerosol particles from measured air. From another side all selected particles needs in great care. This demand carried out from method of measurement of bacteria in sample by counting of colonies that grew from bacteria on nutrient media after incubation time. It is a problem to prevent bacterial flora from death during collecting aerosol sample. This time of growth and counting of colony is so long that result of this measurement will be unusable if it will be terrorist action of start of bacteriological was. Here presented new methods for fast diagnostics of the bacteria in the air. It consists from 4 general parts: (1) Micro-droplet method for diagnostics of biological active substances in aerosol sample. This method allows to control the bio-particle position on the plate, to use series of biochemistry species for analytical reaction for this small bio-particle. Small volume of biochemical reaction reduces noise. This method provides extremely high sensitivity for discovering of biological material. (2

  1. Modulation of immune homeostasis by commensal bacteria

    Science.gov (United States)

    Ivanov, Ivaylo I.; Littman, Dan R.

    2011-01-01

    Intestinal bacteria form a resident community that has co-evolved with the mammalian host. In addition to playing important roles in digestion and harvesting energy, commensal bacteria are crucial for the proper functioning of mucosal immune defenses. Most of these functions have been attributed to the presence of large numbers of “innocuous” resident bacteria that dilute or occupy niches for intestinal pathogens or induce innate immune responses that sequester bacteria in the lumen, thus quenching excessive activation of the mucosal immune system. However it has recently become obvious that commensal bacteria are not simply beneficial bystanders, but are important modulators of intestinal immune homeostasis and that the composition of the microbiota is a major factor in pre-determining the type and robustness of mucosal immune responses. Here we review specific examples of individual members of the microbiota that modify innate and adaptive immune responses, and we focus on potential mechanisms by which such species-specific signals are generated and transmitted to the host immune system. PMID:21215684

  2. Molecular analysis of deep subsurface bacteria

    International Nuclear Information System (INIS)

    Jimenez Baez, L.E.

    1989-09-01

    Deep sediments samples from site C10a, in Appleton, and sites, P24, P28, and P29, at the Savannah River Site (SRS), near Aiken, South Carolina were studied to determine their microbial community composition, DNA homology and mol %G+C. Different geological formations with great variability in hydrogeological parameters were found across the depth profile. Phenotypic identification of deep subsurface bacteria underestimated the bacterial diversity at the three SRS sites, since bacteria with the same phenotype have different DNA composition and less than 70% DNA homology. Total DNA hybridization and mol %G+C analysis of deep sediment bacterial isolates suggested that each formation is comprised of different microbial communities. Depositional environment was more important than site and geological formation on the DNA relatedness between deep subsurface bacteria, since more 70% of bacteria with 20% or more of DNA homology came from the same depositional environments. Based on phenotypic and genotypic tests Pseudomonas spp. and Acinetobacter spp.-like bacteria were identified in 85 million years old sediments. This suggests that these microbial communities might have been adapted during a long period of time to the environmental conditions of the deep subsurface

  3. Overlapping riboflavin supply pathways in bacteria.

    Science.gov (United States)

    García-Angulo, Víctor Antonio

    2017-03-01

    Riboflavin derivatives are essential cofactors for a myriad of flavoproteins. In bacteria, flavins importance extends beyond their role as intracellular protein cofactors, as secreted flavins are a key metabolite in a variety of physiological processes. Bacteria obtain riboflavin through the endogenous riboflavin biosynthetic pathway (RBP) or by the use of importer proteins. Bacteria frequently encode multiple paralogs of the RBP enzymes and as for other micronutrient supply pathways, biosynthesis and uptake functions largely coexist. It is proposed that bacteria shut down biosynthesis and would rather uptake riboflavin when the vitamin is environmentally available. Recently, the overlap of riboflavin provisioning elements has gained attention and the functions of duplicated paralogs of RBP enzymes started to be addressed. Results point towards the existence of a modular structure in the bacterial riboflavin supply pathways. Such structure uses subsets of RBP genes to supply riboflavin for specific functions. Given the importance of riboflavin in intra and extracellular bacterial physiology, this complex array of riboflavin provision pathways may have developed to contend with the various riboflavin requirements. In riboflavin-prototrophic bacteria, riboflavin transporters could represent a module for riboflavin provision for particular, yet unidentified processes, rather than substituting for the RBP as usually assumed.

  4. Bacteria and plutonium in marine environments

    International Nuclear Information System (INIS)

    Carey, A.E.; Bowen, V.T.

    1978-01-01

    Microbes are important in geochemical cycling of many elements. Recent reports emphasize biogenous particulates and bacterial exometabolites as controlling oceanic distribution of plutonium. Bacteria perform oxidation/reduction reactions on metals such as mercury, nickel, lead, copper, and cadmium. Redox transformations or uptake of Pu by marine bacteria may well proceed by similar mechanisms. Profiles of water samples and sediment cores were obtained along the continental shelf off Nova Scotia and in the Gulf of St. Lawrence. Profiles of water samples, and sediment cores were obtained. Epifluorescent microscopy was used to view bacteria (from water or sediment) after concentration on membrane filters and staining with acridine orange. Radiochemical analyses measured Pu in sediments and water samples. Studies of 237 Pu uptake used a strain of Leucothrix mucor isolated from a macroalga. Enumeration shows bacteria to range 10 4 to 10 5 cells/ml in seawater or 10 7 to 10 8 cells/gram of sediment. These numbers are related to the levels and distrbution of Pu in the samples. In cultures of L. mucor amended with Pu atom concentrations approximating those present in open ocean environments, bacterial cells concentrated 237 Pu slower and to lower levels than did clay minerals, glass beads, or phytoplankton. These data further clarify the role of marine bacteria in Pu biogeochemistry

  5. Method of Detecting Coliform Bacteria and Escherichia Coli Bacteria from Reflected Light

    Science.gov (United States)

    Vincent, Robert (Inventor)

    2013-01-01

    The present invention relates to a method of detecting coliform bacteria in water from reflected light and a method of detecting Eschericha Coli bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

  6. COMPETITION BETWEEN ANOXYGENIC PHOTOTROPHIC BACTERIA AND COLORLESS SULFUR BACTERIA IN A MICROBIAL MAT

    NARCIS (Netherlands)

    VISSCHER, PT; VANDENENDE, FP; SCHAUB, BEM; VANGEMERDEN, H

    The populations of chemolithoautotrophic (colorless) sulfur bacteria and anoxygenic phototrophic bacteria were enumerated in a marine microbial mat. The highest population densities were found in the 0-5 mm layer of the mat: 2.0 X 10(9) cells CM-3 sediment, and 4.0 X 10(7) cells cm-3 sediment for

  7. Using Fluorescent Viruses for Detecting Bacteria in Water

    Science.gov (United States)

    Tabacco, Mary Beth; Qian, Xiaohua; Russo, Jaimie A.

    2009-01-01

    A method of detecting water-borne pathogenic bacteria is based partly on established molecular-recognition and fluorescent-labeling concepts, according to which bacteria of a species of interest are labeled with fluorescent reporter molecules and the bacteria can then be detected by fluorescence spectroscopy. The novelty of the present method lies in the use of bacteriophages (viruses that infect bacteria) to deliver the fluorescent reporter molecules to the bacteria of the species of interest.

  8. Lactic Acid Bacteria Exopolysaccharides in Foods and Beverages: Isolation, Properties, Characterization, and Health Benefits.

    Science.gov (United States)

    Lynch, Kieran M; Zannini, Emanuele; Coffey, Aidan; Arendt, Elke K

    2018-03-25

    Exopolysaccharides produced by lactic acid bacteria are a diverse group of polysaccharides produced by many species. They vary widely in their molecular, compositional, and structural characteristics, including mechanisms of synthesis. The physiochemical properties of these polymers mean that they can be exploited for the sensorial and textural enhancement of a variety of food and beverage products. Traditionally, lactic acid bacteria exopolysaccharides have an important role in fermented dairy products and more recently are being applied for the improvement of bakery products. The health benefits that are continually being associated with these polysaccharides enable the development of dual function, added-value, and clean-label products. To fully exploit and understand the functionality of these exopolysaccharides, their isolation, purification, and thorough characterization are of great importance. This review considers each of the above factors and presents the current knowledge on the importance of lactic acid bacteria exopolysaccharides in the food and beverage industry.

  9. Impact of gold nanoparticles combined to X-Ray irradiation on bacteria

    International Nuclear Information System (INIS)

    Simon-Deckers, A.; Gouget, B.; Carriere, M.; Brun, E.; Sicard-Roselli, C.

    2008-01-01

    Recent increase of multi drug-resistant bacteria represents a crucial issue of public health. As innovative approaches are required to face that problem, those emerging from nano-technology are of great interest. In that context we propose the possibility to use gold nano-particles combined with ionising radiation to destroy pathogenic bacteria. For that, we investigated the potential X-Rays enhanced reduction of bacterial cell viability, following nanoparticle exposure, on a bacterial model, Escherichia coli. Our first concern was to confirm the absence of toxicity of the colloidal solution used. Then, we developed an X-Ray irradiation system and showed that gold nanoparticles increased the efficiency of ionising radiation to induce bacteria cell death. (authors)

  10. Comparison of multi-enzyme and thermophilic bacteria on the hydrolysis of mariculture organic waste (MOW).

    Science.gov (United States)

    Guo, Liang; Sun, Mei; Zong, Yan; Zhao, Yangguo; Gao, Mengchun; She, Zonglian

    2016-01-01

    Mariculture organic waste (MOW) is rich in organic matter, which is a potential energy resource for anaerobic digestion. In order to enhance the anaerobic fermentation, the MOW was hydrolyzed by multi-enzyme and thermophilic bacteria. It was advantageous for soluble chemical oxygen demand (SCOD) release at MOW concentrations of 6 and 10 g/L with multi-enzyme and thermophilic bacteria pretreatments. For multi-enzyme, the hydrolysis was not obvious at substrate concentrations of 1 and 3 g/L, and the protein and carbohydrate increased with hydrolysis time at substrate concentrations of 6 and 10 g/L. For thermophilic bacteria, the carbohydrate was first released at 2-4 h and then consumed, and the protein increased with hydrolysis time. The optimal enzyme hydrolysis for MOW was determined by measuring the changes of SCOD, protein, carbohydrate, ammonia and total phosphorus, and comparing with acid and alkaline pretreatments.

  11. Effects of ionizing radiation on bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Suhadi, F [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1976-10-01

    The differences of radiosensitivities among bacteria in addition to the dependence upon the species or strains also depends on the environmental condition during irradiation (temperature, medium, the presence of protective or sensitizing agents, the gas phase or atmosphere, and water activity, or degree of hydration) and on the effects of the environmental condition before and after irradiation treatment (temperature of incubation, age of culture and growth medium). In general, spores are more resistant to radiation than vegetatic bacteria, with the exception that a few cocci are the most radiation resistant bacteria (Micrococcus and Streptococcus). The application of ionizing radiation in the fields of microbiology supports the radiation sterilization of medical and pharmaceutical products. In addition, microbiological aspects of food preservation, especially radurization, radicidation, and immunization studies by using irradiated microorganisms, are also important.

  12. Threats and opportunities of plant pathogenic bacteria.

    Science.gov (United States)

    Tarkowski, Petr; Vereecke, Danny

    2014-01-01

    Plant pathogenic bacteria can have devastating effects on plant productivity and yield. Nevertheless, because these often soil-dwelling bacteria have evolved to interact with eukaryotes, they generally exhibit a strong adaptivity, a versatile metabolism, and ingenious mechanisms tailored to modify the development of their hosts. Consequently, besides being a threat for agricultural practices, phytopathogens may also represent opportunities for plant production or be useful for specific biotechnological applications. Here, we illustrate this idea by reviewing the pathogenic strategies and the (potential) uses of five very different (hemi)biotrophic plant pathogenic bacteria: Agrobacterium tumefaciens, A. rhizogenes, Rhodococcus fascians, scab-inducing Streptomyces spp., and Pseudomonas syringae. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Hydrodynamic interaction between bacteria and passive sphere

    Science.gov (United States)

    Zhang, Bokai; Ding, Yang; Xu, Xinliang

    2017-11-01

    Understanding hydrodynamic interaction between bacteria and passive sphere is important for identifying rheological properties of bacterial and colloidal suspension. Over the past few years, scientists mainly focused on bacterial influences on tracer particle diffusion or hydrodynamic capture of a bacteria around stationary boundary. Here, we use superposition of singularities and regularized method to study changes in bacterial swimming velocity and passive sphere diffusion, simultaneously. On this basis, we present a simple two-bead model that gives a unified interpretation of passive sphere diffusion and bacterial swimming. The model attributes both variation of passive sphere diffusion and changes of speed of bacteria to an effective mobility. Using the effective mobility of bacterial head and tail as an input function, the calculations are consistent with simulation results at a broad range of tracer diameters, incident angles and bacterial shapes.

  14. Interactions among sulfide-oxidizing bacteria

    Science.gov (United States)

    Poplawski, R.

    1985-01-01

    The responses of different phototrophic bacteria in a competitive experimental system are studied, one in which primary factors such as H2S or light limited photometabolism. Two different types of bacteria shared one limited source of sulfide under specific conditions of light. The selection of a purple and a green sulfur bacteria and the cyanobacterium was based on their physiological similarity and also on the fact that they occur together in microbial mats. They all share anoxygenic photosynthesis, and are thus probably part of an evolutionary continuum of phototrophic organisms that runs from, strictly anaerobic physiology to the ability of some cyanobacteria to shift between anoxygenic bacterial style photosynthesis and the oxygenic kind typical of eukaryotes.

  15. Copper tolerance and virulence in bacteria

    Science.gov (United States)

    Ladomersky, Erik; Petris, Michael J.

    2015-01-01

    Copper (Cu) is an essential trace element for all aerobic organisms. It functions as a cofactor in enzymes that catalyze a wide variety of redox reactions due to its ability to cycle between two oxidation states, Cu(I) and Cu(II). This same redox property of copper has the potential to cause toxicity if copper homeostasis is not maintained. Studies suggest that the toxic properties of copper are harnessed by the innate immune system of the host to kill bacteria. To counter such defenses, bacteria rely on copper tolerance genes for virulence within the host. These discoveries suggest bacterial copper intoxication is a component of host nutritional immunity, thus expanding our knowledge of the roles of copper in biology. This review summarizes our current understanding of copper tolerance in bacteria, and the extent to which these pathways contribute to bacterial virulence within the host. PMID:25652326

  16. Lethal photosensitization of biofilm-grown bacteria

    Science.gov (United States)

    Wilson, Michael

    1997-12-01

    Antibacterial agents are increasingly being used for the prophylaxis and treatment of oral diseases. As these agents can be rendered ineffective by resistance development in the target organisms there is a need to develop alternative antimicrobial approaches. Light-activated antimicrobial agents release singlet oxygen and free radicals which can kill adjacent bacteria and a wide range of cariogenic and periodontopathogenic bacteria has been shown to be susceptible to such agents. In the oral cavity these organisms are present as biofilms (dental plaques) which are less susceptible to traditional antimicrobial agents than bacterial suspensions. The results of these studies have shown that biofilm-grown oral bacteria are also susceptible to lethal photosensitization although the light energy doses required are grater than those needed to kill the organisms when they are grown as aqueous suspensions.

  17. Gastric spiral bacteria in small felids.

    Science.gov (United States)

    Kinsel, M J; Kovarik, P; Murnane, R D

    1998-06-01

    Nine small cats, including one bobcat (Felis rufus), one Pallas cat (F. manul), one Canada lynx (F. lynx canadensis), two fishing cats (F. viverrina), two margays (F. wiedii), and two sand cats (F. margarita), necropsied between June 1995 and March 1997 had large numbers of gastric spiral bacteria, whereas five large cats, including one African lion (Panthera leo), two snow leopards (P. uncia), one Siberian tiger (P. tigris altaica), and one jaguar (P. onca), necropsied during the same period had none. All of the spiral organisms from the nine small cats were histologically and ultrastructurally similar. Histologically, the spiral bacteria were 5-14 microm long with five to nine coils per organism and were located both extracellularly within gastric glands and surface mucus, and intracellularly in parietal cells. Spiral bacteria in gastric mucosal scrapings from the Canada lynx, one fishing cat, and the two sand cats were gram negative and had corkscrewlike to tumbling motility when viewed with phase contrast microscopy. The bacteria were 0.5-0.7 microm wide, with a periodicity of 0.65-1.1 microm in all cats. Bipolar sheathed flagella were occasionally observed, and no periplasmic fibrils were seen. The bacteria were extracellular in parietal cell canaliculi and intracellular within parietal cells. Culture of mucosal scrapings from the Canada lynx and sand cats was unsuccessful. Based on morphology, motility, and cellular tropism, the bacteria were probably Helicobacter-like organisms. Although the two margays had moderate lymphoplasmacytic gastritis, the other cats lacked or had only mild gastric lymphoid infiltrates, suggesting that these organisms are either commensals or opportunistic pathogens.

  18. Exogenous fatty acid metabolism in bacteria.

    Science.gov (United States)

    Yao, Jiangwei; Rock, Charles O

    2017-10-01

    Bacterial type II fatty acid synthesis (FASII) is a target for novel antibiotic development. All bacteria encode for mechanisms to incorporate exogenous fatty acids, and some bacteria can use exogenous fatty acids to bypass FASII inhibition. Bacteria encode three different mechanisms for activating exogenous fatty acids for incorporation into phospholipid synthesis. Exogenous fatty acids are converted into acyl-CoA in Gammaproteobacteria such as E. coli. Acyl-CoA molecules constitute a separate pool from endogenously synthesized acyl-ACP. Acyl-CoA can be used for phospholipid synthesis or broken down by β-oxidation, but cannot be used for lipopolysaccharide synthesis. Exogenous fatty acids are converted into acyl-ACP in some Gram-negative bacteria. The resulting acyl-ACP undergoes the same fates as endogenously synthesized acyl-ACP. Exogenous fatty acids are converted into acyl-phosphates in Gram-positive bacteria, and can be used for phospholipid synthesis or become acyl-ACP. Only the order Lactobacillales can use exogenous fatty acids to bypass FASII inhibition. FASII shuts down completely in presence of exogenous fatty acids in Lactobacillales, allowing Lactobacillales to synthesize phospholipids entirely from exogenous fatty acids. Inhibition of FASII cannot be bypassed in other bacteria because FASII is only partially down-regulated in presence of exogenous fatty acid or FASII is required to synthesize essential metabolites such as β-hydroxyacyl-ACP. Certain selective pressures such as FASII inhibition or growth in biofilms can select for naturally occurring one step mutations that attenuate endogenous fatty acid synthesis. Although attempts have been made to estimate the natural prevalence of these mutants, culture-independent metagenomic methods would provide a better estimate. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  19. Isolation of Biosurfactant Producing Bacteria from Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    A Tabatabaee, M Mazaheri Assadi, AA Noohi,VA Sajadian

    2005-01-01

    Full Text Available Biosurfactants or surface-active compounds are produced by microoaganisms. These molecules reduce surface tension both aqueous solutions and hydrocarbon mixtures. In this study, isolation and identification of biosurfactant producing bacteria were assessed. The potential application of these bacteria in petroleum industry was investigated. Samples (crude oil were collected from oil wells and 45 strains were isolated. To confirm the ability of isolates in biosurfactant production, haemolysis test, emulsification test and measurement of surface tension were conducted. We also evaluated the effect of different pH, salinity concentrations, and temperatures on biosurfactant production. Among importance features of the isolated strains, one of the strains (NO.4: Bacillus.sp showed high salt tolerance and their successful production of biosurfactant in a vast pH and temperature domain and reduced surface tension to value below 40 mN/m. This strain is potential candidate for microbial enhanced oil recovery. The strain4 biosurfactant component was mainly glycolipid in nature.

  20. Utilization of bacteriocin-producing bacteria in dairy products

    Directory of Open Access Journals (Sweden)

    Matěj Patrovský

    2016-07-01

    Full Text Available Lactic acid bacteria have been used since ancient times for food preparation and for bio-conservation by fermentation. Selected strains are capable of producing antimicrobial peptides - bacteriocins, which can be natural preservatives, especially in products with short shelf lives. The present study is focused on inhibitory effects of the bacteriocin-producing bacteria strains Enterococcus faecium, Pediococccus acidilactici and Lactobacillus plantarum against Listeria innocua as an indicator microorganism. Freeze-dried preparations of bacterial strains producing particular bacteriocins were tested by agar well-diffusion assay and by the traditional spread plate method. Plantaricin exhibited the highest anti-listerial effect among the tested bacteriocins. Pediocin also demonstrated a distinct inhibitory effect, but enterocin appeared to be heat labile and its efficiency was also suppressed under cold storage conditions. Plantaricin reduced Listeria innocua counts by 1 log in dairy spread made from cheese and quark. The formation of bacteriocins by various Lactobacillus plantarum strains were substantially influenced by the cultivation conditions of the mother culture and by the microbial preparation process before freeze-drying. Bacteriocins introduced into foodstuffs via protective cultures in situ offer new perspectives on enhancing food quality and safety.

  1. Subsurface Endospore-Forming Bacteria Possess Bio-Sealant Properties.

    Science.gov (United States)

    Basha, Sreenivasulu; Lingamgunta, Lakshman Kumar; Kannali, Jayakumar; Gajula, Swarna Kumari; Bandikari, Ramesh; Dasari, Sreenivasulu; Dalavai, Veena; Chinthala, Paramageetham; Gundala, Prasada Babu; Kutagolla, Peera; Balaji, Vinodh Kumar

    2018-04-24

    Concrete is a strong and fairly inexpensive building substance, but has several disadvantages like cracking that allows corrosion, thus reducing its lifespan. To mitigate these complications, long-lasting microbial self-healing cement is an alternative that is eco-friendly and also actively repairs cracks. The present paper describes the detailed experimental investigation on compressive strength of cement mortars, mixed with six alkaliphilic bacteria, isolated from subsurface mica mines of high alkalinity. The experiments showed that the addition of alkaliphilic isolates at different cell concentrations (10 4 and 10 6 cells/ml) enhanced the compressive strength of cement mortar, because the rapid growth of bacteria at high alkalinity precipitates calcite crystals that lead to filling of pores and densifying the concrete mix. Thus, Bacillus subtilis (SVUNM4) showed the highest compressive strength (28.61%) of cement mortar at 10 4 cells/ml compared to those of other five alkaliphilic isolates (Brevibacillus sp., SVUNM15-22.1%; P. dendritiformis, SVUNM11-19.9%; B. methylotrophicus, SVUNM9-16%; B. licheniformis, SVUNM14-12.7% and S. maltophilia, SVUNM13-9.6%) and controlled cement mortar as well. This method resulted in the filling of cracks in concrete with calcite (CaCO 3 ), which was observed by scanning electron microscopy (SEM). Our results showed that the alkaliphilic bacterial isolates used in the study are effective in self-healing and repair of concrete cracks.

  2. Recent Developments for Remediating Acidic Mine Waters Using Sulfidogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Ivan Nancucheo

    2017-01-01

    Full Text Available Acidic mine drainage (AMD is regarded as a pollutant and considered as potential source of valuable metals. With diminishing metal resources and ever-increasing demand on industry, recovering AMD metals is a sustainable initiative, despite facing major challenges. AMD refers to effluents draining from abandoned mines and mine wastes usually highly acidic that contain a variety of dissolved metals (Fe, Mn, Cu, Ni, and Zn in much greater concentration than what is found in natural water bodies. There are numerous remediation treatments including chemical (lime treatment or biological methods (aerobic wetlands and compost bioreactors used for metal precipitation and removal from AMD. However, controlled biomineralization and selective recovering of metals using sulfidogenic bacteria are advantageous, reducing costs and environmental risks of sludge disposal. The increased understanding of the microbiology of acid-tolerant sulfidogenic bacteria will lead to the development of novel approaches to AMD treatment. We present and discuss several important recent approaches using low sulfidogenic bioreactors to both remediate and selectively recover metal sulfides from AMD. This work also highlights the efficiency and drawbacks of these types of treatments for metal recovery and points to future research for enhancing the use of novel acidophilic and acid-tolerant sulfidogenic microorganisms in AMD treatment.

  3. Insect symbiotic bacteria harbour viral pathogens for transovarial transmission.

    Science.gov (United States)

    Jia, Dongsheng; Mao, Qianzhuo; Chen, Yong; Liu, Yuyan; Chen, Qian; Wu, Wei; Zhang, Xiaofeng; Chen, Hongyan; Li, Yi; Wei, Taiyun

    2017-03-06

    Many insects, including mosquitoes, planthoppers, aphids and leafhoppers, are the hosts of bacterial symbionts and the vectors for transmitting viral pathogens 1-3 . In general, symbiotic bacteria can indirectly affect viral transmission by enhancing immunity and resistance to viruses in insects 3-5 . Whether symbiotic bacteria can directly interact with the virus and mediate its transmission has been unknown. Here, we show that an insect symbiotic bacterium directly harbours a viral pathogen and mediates its transovarial transmission to offspring. We observe rice dwarf virus (a plant reovirus) binding to the envelopes of the bacterium Sulcia, a common obligate symbiont of leafhoppers 6-8 , allowing the virus to exploit the ancient oocyte entry path of Sulcia in rice leafhopper vectors. Such virus-bacterium binding is mediated by the specific interaction of the viral capsid protein and the Sulcia outer membrane protein. Treatment with antibiotics or antibodies against Sulcia outer membrane protein interferes with this interaction and strongly prevents viral transmission to insect offspring. This newly discovered virus-bacterium interaction represents the first evidence that a viral pathogen can directly exploit a symbiotic bacterium for its transmission. We believe that such a model of virus-bacterium communication is a common phenomenon in nature.

  4. Detection of Foodborne Pathogenic Bacteria using Bacteriophage Tail Spike Proteins

    Science.gov (United States)

    Poshtiban, Somayyeh

    Foodborne infections are worldwide health problem with tremendous social and financial impacts. Efforts are focused on developing accurate and reliable technologies for detection of food contaminations in early stages preferably on-site. This thesis focuses on interfacing engineering and biology by combining phage receptor binding proteins (RBPs) with engineered platforms including microresonator-based biosensors, magnetic particles and polymerase chain reaction (PCR) to develop bacterial detection sensors. We used phage RBPs as target specific bioreceptors to develop an enhanced microresonator array for bacterial detection. These resonator beams are optimized to feature a high natural frequency while offer large surface area for capture of bacteria. Theoretical analysis indicates a high mass sensitivity with a threshold for the detection of a single bacterial cell. We used phage RBPs as target specific bioreceptors, and successfully demonstrated the application of these phage RBB-immobilized arrays for specific detection of C. jejuni cells. We also developed a RBP-derivatized magnetic pre-enrichment method as an upstream sample preparation method to improve sensitivity and specificity of PCR for detection of bacterial cells in various food samples. The combination of RBP-based magnetic separation and real-time PCR allowed the detection of small number of bacteria in artificially contaminated food samples without any need for time consuming pre-enrichment step through culturing. We also looked into integration of the RBP-based magnetic separation with PCR onto a single microfluidic lab-on-a-chip to reduce the overall turnaround time.

  5. Differential staining of bacteria: gram stain.

    Science.gov (United States)

    Moyes, Rita B; Reynolds, Jackie; Breakwell, Donald P

    2009-11-01

    In 1884, Hans Christian Gram, a Danish doctor, developed a differential staining technique that is still the cornerstone of bacterial identification and taxonomic division. This multistep, sequential staining protocol separates bacteria into four groups based on cell morphology and cell wall structure: Gram-positive cocci, Gram-negative cocci, Gram-positive rods, and Gram-negative rods. The Gram stain is useful for assessing bacterial contamination of tissue culture samples or for examining the Gram stain status and morphological features of bacteria isolated from mixed or isolated bacterial cultures. (c) 2009 by John Wiley & Sons, Inc.

  6. Motile bacteria in a critical fluid mixture

    Science.gov (United States)

    Koumakis, Nick; Devailly, Clémence; Poon, Wilson C. K.

    2018-06-01

    We studied the swimming of Escherichia coli bacteria in the vicinity of the critical point in a solution of the nonionic surfactant C12E5 in buffer solution. In phase-contrast microscopy, each swimming cell produces a transient trail behind itself lasting several seconds. Comparing quantitative image analysis with simulations show that these trails are due to local phase reorganization triggered by differential adsorption. This contrasts with similar trails seen in bacteria swimming in liquid crystals, which are due to shear effects. We show how our trails are controlled, and use them to probe the structure and dynamics of critical fluctuations in the fluid medium.

  7. Bacteria Provide Cleanup of Oil Spills, Wastewater

    Science.gov (United States)

    2010-01-01

    Through Small Business Innovation Research (SBIR) contracts with Marshall Space Flight Center, Micro-Bac International Inc., of Round Rock, Texas, developed a phototrophic cell for water purification in space. Inside the cell: millions of photosynthetic bacteria. Micro-Bac proceeded to commercialize the bacterial formulation it developed for the SBIR project. The formulation is now used for the remediation of wastewater systems and waste from livestock farms and food manufacturers. Strains of the SBIR-derived bacteria also feature in microbial solutions that treat environmentally damaging oil spills, such as that resulting from the catastrophic 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico.

  8. Functional Encyclopedia of Bacteria and Archaea

    Energy Technology Data Exchange (ETDEWEB)

    Blow, M. J.; Deutschbauer, A. M.; Hoover, C. A.; Lamson, J.; Lamson, J.; Price, M. N.; Waters, J.; Wetmore, K. M.; Bristow, J.; Arkin, A. P.

    2013-03-20

    Bacteria and Archaea exhibit a huge diversity of metabolic capabilities with fundamental importance in the environment, and potential applications in biotechnology. However, the genetic bases of these capabilities remain unclear due largely to an absence of technologies that link DNA sequence to molecular function. To address this challenge, we are developing a pipeline for high throughput annotation of gene function using mutagenesis, growth assays and DNA sequencing. By applying this pipeline to annotate gene function in 50 diverse microbes we hope to discover thousands of new gene functions and produce a proof of principle `Functional Encyclopedia of Bacteria and Archaea?.

  9. Beer spoilage bacteria and hop resistance.

    Science.gov (United States)

    Sakamoto, Kanta; Konings, Wil N

    2003-12-31

    For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and Megasphaera cerevisiae. They can spoil beer by turbidity, acidity and the production of unfavorable smell such as diacetyl or hydrogen sulfide. For the microbiological control, many advanced biotechnological techniques such as immunoassay and polymerase chain reaction (PCR) have been applied in place of the conventional and time-consuming method of incubation on culture media. Subsequently, a method is needed to determine whether the detected bacterium is capable of growing in beer or not. In lactic acid bacteria, hop resistance is crucial for their ability to grow in beer. Hop compounds, mainly iso-alpha-acids in beer, have antibacterial activity against Gram-positive bacteria. They act as ionophores which dissipate the pH gradient across the cytoplasmic membrane and reduce the proton motive force (pmf). Consequently, the pmf-dependent nutrient uptake is hampered, resulting in cell death. The hop-resistance mechanisms in lactic acid bacteria have been investigated. HorA was found to excrete hop compounds in an ATP-dependent manner from the cell membrane to outer medium. Additionally, increased proton pumping by the membrane bound H(+)-ATPase contributes to hop resistance. To energize such ATP-dependent transporters hop-resistant cells contain larger ATP pools than hop-sensitive cells. Furthermore, a pmf-dependent hop transporter was recently presented. Understanding the hop-resistance mechanisms has enabled the development of rapid methods to discriminate beer spoilage strains from nonspoilers. The horA-PCR method has been applied for bacterial control in breweries. Also, a discrimination method was developed based on ATP pool measurement in lactobacillus cells. However

  10. Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei)

    OpenAIRE

    Wilis Ari Setyati; Muhammad Zainuddin; Person Pesona Renta

    2017-01-01

    Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36...

  11. Plant growth-promoting bacteria for phytostabilization of mine tailings.

    Science.gov (United States)

    Grandlic, Christopher J; Mendez, Monica O; Chorover, Jon; Machado, Blenda; Maier, Raina M

    2008-03-15

    Eolian dispersion of mine tailings in arid and semiarid environments is an emerging global issue for which economical remediation alternatives are needed. Phytostabilization, the revegetation of these sites with native plants, is one such alternative. Revegetation often requires the addition of bulky amendments such as compost which greatly increases cost. We report the use of plant growth-promoting bacteria (PGPB) to enhance the revegetation of mine tailings and minimize the need for compost amendment. Twenty promising PGPB isolates were used as seed inoculants in a series of greenhouse studies to examine revegetation of an extremely acidic, high metal contenttailings sample previously shown to require 15% compost amendment for normal plant growth. Several isolates significantly enhanced growth of two native species, quailbush and buffalo grass, in tailings. In this study, PGPB/compost outcomes were plant specific; for quailbush, PGPB were most effective in combination with 10% compost addition while for buffalo grass, PGPB enhanced growth in the complete absence of compost. Results indicate that selected PGPB can improve plant establishment and reduce the need for compost amendment. Further, PGPB activities necessary for aiding plant growth in mine tailings likely include tolerance to acidic pH and metals.

  12. The interaction of Plutonium with Bacteria in the Repository Environment

    International Nuclear Information System (INIS)

    Gillow, J. B.; Francis, A. J.; Lucero, D. A.; Papenguth, H. W.

    2000-01-01

    Microorganisms in the nuclear waste repository environment may interact with plutonium through (1) sorption, (2) intracellular accumulation, and (3) transformation speciation. These interactions may retard or enhance the mobility of Pu by precipitation reactions, biocolloid formation, or production of more soluble species. Current and planned radioactive waste repository environments, such as deep subsurface halite and granite formations, are considered extreme relative to life processes in the near-surface terrestrial environment. There is a paucity of information on the biotransformation of radionuclides by microorganisms present in such extreme environments. In order to gain a better understanding of the interaction of plutonium with microorganisms present in the waste repository sites we investigated a pure culture (Halomonas sp.) and a mixed culture of bacteria (Haloarcula sinaiiensis, Marinobacter hydrocarbonoclasticus, Altermonas sp., and a γ-proteobacterium) isolated from the Waste Isolation Pilot Plant (WIPP) site and an Acetobacterium sp. from alkaline groundwater at the Grimsel Test Site in Switzerland

  13. Lessons from Digestive-Tract Symbioses Between Bacteria and Invertebrates.

    Science.gov (United States)

    Graf, Joerg

    2016-09-08

    In most animals, digestive tracts harbor the greatest number of bacteria in the animal that contribute to its health: by aiding in the digestion of nutrients, provisioning essential nutrients and protecting against colonization by pathogens. Invertebrates have been used to enhance our understanding of metabolic processes and microbe-host interactions owing to experimental advantages. This review describes how advances in DNA sequencing technologies have dramatically altered how researchers investigate microbe-host interactions, including 16S rRNA gene surveys, metagenome experiments, and metatranscriptome studies. Advantages and challenges of each of these approaches are described herein. Hypotheses generated through omics studies can be directly tested using site-directed mutagenesis, and findings from transposon studies and site-directed experiments are presented. Finally, unique structural aspects of invertebrate digestive tracts that contribute to symbiont specificity are presented. The combination of omics approaches with genetics and microscopy allows researchers to move beyond correlations to identify conserved mechanisms of microbe-host interactions.

  14. [Antibacterial activity of rare Streptomyces species against clinical resistant bacteria].

    Science.gov (United States)

    Boughachiche, Faiza; Reghioua, Sihem; Zerizer, Habiba; Boulahrouf, Abderrahmane

    2012-01-01

    In the search for new antibiotics from Steptomyces, investigating extremes habitats enhances the probability of isolating novel producers. In this context, the antibacterial activity of four Streptomyces strains isolated from Ezzmoul saltpans was studied. Two of them showed antibacterial activity against antibiotic's resistant bacteria (Bacillus cereus: β-lactamines and sulfamides resistant, Streptococcus faecalis: penicillin, tetracycline and cotrimoxazole resistant, and Staphylococcus aureus Mu 50: vancomycine resistant). The most active Streptomyces strain produces one type of polar bioactive molecules that resists to temperature variation and light exposition. Its activity appears in the first culture day and reaches its maximal value in the fourth day. The second strain presents themoresistant activity that reaches its maximal value in the first culture day. It produces two types of bioactive molecules, one is polar and the second is non polar (according to thin layer chromatography technique results).

  15. Elevated temperature increases carbon and nitrogen fluxes between phytoplankton and heterotrophic bacteria through physical attachment

    KAUST Repository

    Arandia-Gorostidi, Nestor

    2016-12-06

    Quantifying the contribution of marine microorganisms to carbon and nitrogen cycles and their response to predicted ocean warming is one of the main challenges of microbial oceanography. Here we present a single-cell NanoSIMS isotope analysis to quantify C and N uptake by free-living and attached phytoplankton and heterotrophic bacteria, and their response to short-term experimental warming of 4 °C. Elevated temperature increased total C fixation by over 50%, a small but significant fraction of which was transferred to heterotrophs within 12 h. Cell-to-cell attachment doubled the secondary C uptake by heterotrophic bacteria and increased secondary N incorporation by autotrophs by 68%. Warming also increased the abundance of phytoplankton with attached heterotrophs by 80%, and promoted C transfer from phytoplankton to bacteria by 17% and N transfer from bacteria to phytoplankton by 50%. Our results indicate that phytoplankton-bacteria attachment provides an ecological advantage for nutrient incorporation, suggesting a mutualistic relationship that appears to be enhanced by temperature increases.

  16. Proteomic insights into intra- and intercellular plant-bacteria symbiotic association during root nodule formation

    Directory of Open Access Journals (Sweden)

    Afshin eSalavati

    2013-02-01

    Full Text Available Over the last several decades, there have been a large number of studies done on the all aspects of legumes and bacteria which participate in nitrogen-fixing symbiosis. The analysis of legume-bacteria interaction is not just a matter of numerical complexity in terms of variants of gene products that can arise from a single gene. Bacteria regulate their quorum-sensing genes to enhance their ability to induce conjugation of plasmids and symbiotic islands, and various protein secretion mechanisms; that can stimulate a collection of chain reactions including species-specific combinations of plant-secretion isoflavonoids, complicated calcium signaling pathways and autoregulation of nodulation mechanisms. Quorum-sensing systems are introduced by the intra- and intercellular organization of gene products lead to protein–protein interactions or targeting of proteins to specific cellular structures. In this study, an attempt has been made to review significant contributions related to nodule formation and development and their impacts on cell proteome for better understanding of plant-bacterium interaction mechanism at protein level. This review would not only provide new insights into the plant-bacteria symbiosis response mechanisms but would also highlights the importance of studying changes in protein abundance inside and outside of cells in response to symbiosis. Furthermore, the application to agriculture programe of plant-bacteria interaction will be discussed.

  17. Vancomycin-functionalised Ag-TiO{sub 2} phototoxicity for bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wan Yi [Chinese Academy of Sciences, Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, 7 Nanhai Road, Qingdao 266071 (China); Zhang Dun, E-mail: zhangdun@ms.qdio.ac.cn [Chinese Academy of Sciences, Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, 7 Nanhai Road, Qingdao 266071 (China); Wang Yi; Qi Peng; Wu Jiajia; Hou Baorong [Chinese Academy of Sciences, Key Lab of Corrosion Science, Shandong Province, Institute of Oceanology, 7 Nanhai Road, Qingdao 266071 (China)

    2011-02-15

    Research highlights: {yields} A multivalent interaction between Van-Ag-TiO{sub 2} and SRB. {yields} Van-Ag-TiO{sub 2} allow for selective photokilling of pathogen. {yields} Van-Ag-TiO{sub 2} show certain bactericidal property in dark. - Abstract: This study reports on the synthesis of vancomycin (Van)-functionalised Ag-TiO{sub 2} nanoparticles and their enhanced bactericidal activities. Van-Ag-TiO{sub 2} nanoparticles were prepared by nanoparticle deposition and chemical cross-linking reactions. The catalysts showed high efficiency for the degradation of methylene blue under ultraviolet (UV) illumination. The photocatalytic inactivation of the sulphate-reducing bacteria, Desulfotomaculum, was also studied under UV light irradiation and in the dark using aqueous mixtures of Ag, Ag-SiO{sub 2}, Ag-TiO{sub 2}, and Van-Ag-TiO{sub 2}. The Van-Ag-TiO{sub 2} nanoparticles showed a capacity to target Van-sensitive bacteria. They also effectively prevented bacterial cell growth through the functionalised nanoparticles under UV irradiation for 1 h. To investigate the specificity of the catalyst phototoxicity, a Van-resistant bacteria, Vibrio anguillarum, was used as the negative control. The results indicated that Van-Ag-TiO{sub 2} nanoparticles had a higher selective phototoxicity for Van-sensitive bacteria. Therefore, the antibiotic molecule-functionalised core-shell nanoparticles allow for selective photokilling of pathogenic bacteria.

  18. Elevated temperature increases carbon and nitrogen fluxes between phytoplankton and heterotrophic bacteria through physical attachment

    KAUST Repository

    Arandia-Gorostidi, Nestor; Weber, Peter K; Alonso-Sá ez, Laura; Moran, Xose Anxelu G.; Mayali, Xavier

    2016-01-01

    Quantifying the contribution of marine microorganisms to carbon and nitrogen cycles and their response to predicted ocean warming is one of the main challenges of microbial oceanography. Here we present a single-cell NanoSIMS isotope analysis to quantify C and N uptake by free-living and attached phytoplankton and heterotrophic bacteria, and their response to short-term experimental warming of 4 °C. Elevated temperature increased total C fixation by over 50%, a small but significant fraction of which was transferred to heterotrophs within 12 h. Cell-to-cell attachment doubled the secondary C uptake by heterotrophic bacteria and increased secondary N incorporation by autotrophs by 68%. Warming also increased the abundance of phytoplankton with attached heterotrophs by 80%, and promoted C transfer from phytoplankton to bacteria by 17% and N transfer from bacteria to phytoplankton by 50%. Our results indicate that phytoplankton-bacteria attachment provides an ecological advantage for nutrient incorporation, suggesting a mutualistic relationship that appears to be enhanced by temperature increases.

  19. Soil and Waste Matrix Affects Spatial Heterogeneity of Bacteria Filtration during Unsaturated Flow

    Directory of Open Access Journals (Sweden)

    Adrian Unc

    2015-02-01

    Full Text Available Discontinuous flows resulting from discrete natural rain events induce temporal and spatial variability in the transport of bacteria from organic waste through soils in which the degree of saturation varies. Transport and continuity of associated pathways are dependent on structure and stability of the soil under conditions of variable moisture and ionic strength of the soil solution. Lysimeters containing undisturbed monoliths of clay, clay loam or sandy loam soils were used to investigate transport and pathway continuity for bacteria and hydrophobic fluorescent microspheres. Biosolids, to which the microspheres were added, were surface applied and followed by serial irrigation events. Microspheres, Escherichia coli, Enterococcus spp., Salmonella spp. and Clostridium perfringens were enumerated in drainage collected from 64 distinct collection areas through funnels installed in a grid pattern at the lower boundary of the monoliths. Bacteria-dependent filtration coefficients along pathways of increasing water flux were independent of flow volume, suggesting: (1 tracer or colloid dependent retention; and (2 transport depended on the total volume of contiguous pores accessible for bacteria transport. Management decisions, in this case resulting from the form of organic waste, induced changes in tortuosity and continuity of pores and modified the effective capacity of soil to retain bacteria. Surface application of liquid municipal biosolids had a negative impact on transport pathway continuity, relative to the solid municipal biosolids, enhancing retention under less favourable electrostatic conditions consistent with an initial increase in straining within inactive pores and subsequent by limited re-suspension from reactivated pores.

  20. Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters.

    Science.gov (United States)

    Martínez-Rodríguez, Julia del C; De la Mora-Amutio, Marcela; Plascencia-Correa, Luis A; Audelo-Regalado, Esmeralda; Guardado, Francisco R; Hernández-Sánchez, Elías; Peña-Ramírez, Yuri J; Escalante, Adelfo; Beltrán-García, Miguel J; Ogura, Tetsuya

    2014-01-01

    Agave tequilana Weber var. 'Azul' is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost.

  1. Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters

    Directory of Open Access Journals (Sweden)

    Julia del C. Martínez-Rodríguez

    2014-12-01

    Full Text Available Agave tequilana Weber var. 'Azul' is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI. Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost.

  2. Effect of non-Legionellaceae bacteria on the multiplication of Legionella pneumophila in potable water.

    Science.gov (United States)

    Wadowsky, R M; Yee, R B

    1985-05-01

    A naturally occurring suspension of Legionella pneumophila and associated microbiota contained three unidentified non-Legionellaceae bacteria which supported satellite growth of a subculture of L. pneumophila on an L-cysteine-deficient medium and another bacterium which did not support growth of the subculture. Washed suspensions containing 10(3), 10(5), 10(7), or 10(8) CFU of a mixture of isolates of these non-Legionellaceae bacteria failed to support the multiplication of an isolate of agar-grown L. pneumophila which had been washed and seeded into the suspensions. The suspensions which contained 10(3), 10(5), or 10(7) CFU of the non-Legionellaceae bacteria per ml appeared to enhance survival or cryptic growth of agar-grown L. pneumophila. A decline of 1.3 log CFU of L. pneumophila per ml occurred within the first week of incubation in the sample which contained 10(8) CFU of the non-Legionellaceae bacteria per ml. In contrast to these results, naturally occurring L. pneumophila multiplied in the presence of associated microbiota. The necessity to subculture L. pneumophila and the non-Legionellaceae bacteria on artificial medium to obtain pure cultures may have affected the multiplication of L. pneumophila in tap water. Alternatively, other microorganisms may be present in the naturally occurring suspension which support the growth of this bacterium.

  3. Cultivation of bacteria with ecological capsules in space

    Science.gov (United States)

    Sugiura, K.; Hashimoto, H.; Ishikawa, Y.; Kawasaki, Y.; Kobayashi, K.; Seki, K.; Koike, J.; Saito, T.

    1999-01-01

    A hermetically materially-closed aquatic microcosm containing bacteria, algae, and invertebrates was developed as a tool for determining the changes of ecological systems in space. The species composition was maintained for more than 365 days. The microcosm could be readily replicated. The results obtained from the simulation models indicated that there is a self-regulation homeostasis in coupling of production and consumption, which make the microcosm remarkably stable, and that the transfer of metabolites by diffusion is one of the important factors determining the behavior of the system. The microcosms were continuously irradiated using a 60 Co source. After 80 days, no elimination of organisms was found at any of the three irradiation levels (0.015, 0.55 and 3.0 mGy/day). The number of radio-resistance bacteria mutants was not increased in the microcosm at three irradiation levels. We proposed to research whether this microcosm is self-sustainable in space. When an aquatic ecosystem comes under stress due to the micro-gravity and enhanced radiation environment in space, whether the ecosystem is self-sustainable is not known. An aquatic ecosystem shows what happens as a result of the self-organizational processes of selection and adaptation. A microcosm is a useful tool for understanding such processes. We have proposed researching whether a microcosm is self-sustainable in space. The benefits of this project will be: (1) To acquire data for design of a Controlled Ecological Life Support System, (2) Possibility of microbial mutation in a space station. We report that a hermetically materially-closed microcosm, which could be a useful tool for determining changes of ecological processes in space, was developed, and that the effects of microgravity and enhanced radiation on the hermetically materially-closed microcosm were estimated through measurements on the Earth and simulation models.

  4. Microalgae growth-promoting bacteria: A novel approach in wastewater treatment

    Directory of Open Access Journals (Sweden)

    Luz E. de-Bashan

    2003-07-01

    Full Text Available Plant growth-promoting bacteria (PGPB from the genus Azospirillum are known to enhance the growth of numerous agricultural crops. The use of these bacteria is proposed as "micro-algae-growth promoting bacteria" (MGPB for enhancing freshwater micro-algae Chlorella vulgaris and C. sorokiniana capadty to clean polluted water. The deliberate inoculation of Chlorella sp. with a terrestrial PGPB has not been reported prior to these studies, perhaps because of the different origin of the two micro-organisms. Chlorella spp. is not known to harbour any plant growth-promoting bacteria and Azospirillum sp. is rarely used for inoculation in aquatic environments. Co-immobilisation of C. vulgaris and A. brasilense Cd in small alginate beads resulted in significant increases in numerous micro-algae growth parameters. Dry and fresh weight, total number of cells, micro-algal cluster (colonies size within the bead, number of micro-algal cells per cluster and micro-algal pigments levels significantly increased. Lipids and the variety of fatty adds also significantly increased, as did the combination of micro-algae. MGPB had superior capacity for removing ammonium and phosphorus from polluted synthetic and municipal wastewaters than the micro-algae by itself. Other PGPB (i.e. Flavobacterium sp. Azospirillum sp. and Azotobacter sp. are currently being tested in aquaculture; carp farming using enhanced phytoplankton growth and stabilising mass marine micro-algae culture for use as feed for marine organisms are both retuming promising results. This aspect of PGPB effect on water micro-organisms is currently in its infancy. We pro pose that co-immobilising micro-algae and plant growth-promoting bacteria represent an effective means of increasing micro-algal populations and also their capacity for cleaning polluted water. Key words: PGPB; micro-algae; wastewater treatment; co-immobilised

  5. Effects of symbiotic bacteria on chemical sensitivity of Daphnia magna.

    Science.gov (United States)

    Manakul, Patcharaporn; Peerakietkhajorn, Saranya; Matsuura, Tomoaki; Kato, Yasuhiko; Watanabe, Hajime

    2017-07-01

    The crustacean zooplankton Daphnia magna has been widely used for chemical toxicity tests. Although abiotic factors have been well documented in ecotoxicological test protocols, biotic factors that may affect the sensitivity to chemical compounds remain limited. Recently, we identified symbiotic bacteria that are critical for the growth and reproduction of D. magna. The presence of symbiotic bacteria on Daphnia raised the question as to whether these bacteria have a positive or negative effect on toxicity tests. In order to evaluate the effects of symbiotic bacteria on toxicity tests, bacteria-free Daphnia were prepared, and their chemical sensitivities were compared with that of Daphnia with symbiotic bacteria based on an acute immobilization test. The Daphnia with symbiotic bacteria showed higher chemical resistance to nonylphenol, fenoxycarb, and pentachlorophenol than bacteria-free Daphnia. These results suggested potential roles of symbiotic bacteria in the chemical resistance of its host Daphnia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Fermentation of D-Tagatose by Human Intestinal Bacteria and Dairy Lactic Acid Bacteria

    OpenAIRE

    Bertelsen, Hans; Andersen, Hans; Tvede, Michael

    2011-01-01

    A number of 174 normal or pathogenic human enteric bacteria and dairy lactic acid bacteria were screened for D-tagatose fermentation by incubation for 48 hours. Selection criteria for fermentation employed included a drop in pH below 5.5 and a distance to controls of more than 0.5. Only a few of the normal occurring enteric human bacteria were able to ferment D-tagatose, among those Enterococcus faecalis, Enterococcus faecium and Lactobacillus strains. D-Tagatose fermentation seems to be comm...

  7. Brilliant glyconanocapsules for trapping of bacteria.

    Science.gov (United States)

    Yan, Xibo; Sivignon, Adeline; Alcouffe, Pierre; Burdin, Béatrice; Favre-Bonté, Sabine; Bilyy, Rostyslav; Barnich, Nicolas; Fleury, Etienne; Ganachaud, François; Bernard, Julien

    2015-08-28

    Nanoprecipitation of miglyol into droplets surrounded by a functional glycopolymer generates nanocapsules of biointerest. Fluorophores are trapped in situ or post-grafted onto the crosslinked polymer shell for efficient imaging. The resulting colloids induce aggregation of bacteria through strong specific interactions and promote their facile removal.

  8. Brilliant glyconanocapsules for trapping of bacteria

    OpenAIRE

    Yan, Xibo; Sivignon, Adeline; Alcouffe, Pierre; Burdin, Béatrice; Favre-Bonté, Sabine; Bilyy, Rostyslav; Barnich, Nicolas; Fleury, Etienne; Ganachaud, François; Bernard, Julien

    2015-01-01

    Nanoprecipitation of miglyol into droplets surrounded by a functional glycopolymer generates nanocapsules of biointerest. Fluorophores are trapped in situ or post-grafted onto the crosslinked polymer shell for efficient imaging. The resulting colloids induce aggregation of bacteria through strong specific interactions and promote their facile removal.

  9. On Bunsen Burners, Bacteria and the Bible

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 2. On Bunsen Burners, Bacteria and the Bible. Milind Watve. Classroom Volume 1 Issue 2 February 1996 pp 84-89. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/02/0084-0089 ...

  10. The effects of bacteria on crystalline rock

    International Nuclear Information System (INIS)

    Brown, D.A.

    1994-01-01

    Many reactions involving inorganic minerals at water-rock interfaces have now been recognized to be bacterially mediated; these reactions could have a significant effect in the excavation of vaults for toxic and radioactive waste disposal. To investigate the role that bacteria play in the natural aqueous environment of crystalline rock the microbial growth factors of nutrition, energy and environment are described. Microbial activity has been investigated in Atomic Energy of Canada's Underground Research Laboratory (URL), situated in the Archean granitic Lac du Bonnet Batholith, Winnipeg, Manitoba. Faults, initiated in the Early Proterozoic, and later-formed fractures, provide ground-water pathways. Planktonic bacteria, free-swimming in the groundwater, have been observed in over 100 underground borehole samples. The number of bacteria varied from 10 3 to 10 5 mL -1 and appeared to decrease with depth and with increased salinity of the water. However, in the natural environment of deep (100-500 m) crystalline rocks, where nutrition is limited, formation of biofilms by sessile bacteria is a successful survival strategy. Natural biofilms at the URL and biofilms grown in bioreactors have been studied. The biofilms can accumulate different elements, depending upon the local environment. Precipitates of iron have been found in all the biofilms studied, where they are either passively accumulated or utilized as an energy source. Within the biofilm active and extensive biogeochemical immobilization of dissolved elements is controlled by distinct bacterial activities which are sufficiently discrete for hematite and siderite to be precipitated in close proximity

  11. Solvent-tolerant bacteria in biocatalysis.

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1998-01-01

    The toxicity of fine chemicals to the producer organism is a problem in several biotechnological production processes. In several instances, an organic phase can be used to extract the toxic product from the aqueous phase during a fermentation. With the discovery of solvent-tolerant bacteria, more

  12. OCCURRENCE OF PATHOGENIC BACTERIA ASSOCIATED WITH ...

    African Journals Online (AJOL)

    USER

    With the diminishing rate of natural fish resources globally, a reasonable percentage of fish and fish products .... from these artificial fish habitat, one may not be out of place to ... condition for bacteria reproduction and development in their host ...

  13. Identification of bacteria using mass spectrometry techniques

    Czech Academy of Sciences Publication Activity Database

    Krásný, Lukáš; Hynek, R.; Hochel, I.

    2013-01-01

    Roč. 353, NOV 2013 (2013), s. 67-79 ISSN 1387-3806 R&D Projects: GA ČR GAP503/10/0664 Institutional support: RVO:61388971 Keywords : Mass spectrometry * Bacteria * Identification Subject RIV: EE - Microbiology, Virology Impact factor: 2.227, year: 2013

  14. Antimicrobial resistant bacteria in the food chain

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar

    2003-01-01

    Antimicrobials are used for treatment and prevention of disease in food animals and as feed additives for growth promotion. All uses lead to the development of resistant bacteria, some of which are pathogenic to humans. Current main concerns are with resistance in Salmonella and Campylobacter...

  15. Bioluminescent bacteria: lux genes as environmental biosensors

    OpenAIRE

    Nunes-Halldorson,Vânia da Silva; Duran,Norma Letícia

    2003-01-01

    Bioluminescent bacteria are widespread in natural environments. Over the years, many researchers have been studying the physiology, biochemistry and genetic control of bacterial bioluminescence. These discoveries have revolutionized the area of Environmental Microbiology through the use of luminescent genes as biosensors for environmental studies. This paper will review the chronology of scientific discoveries on bacterial bioluminescence and the current applications of bioluminescence in env...

  16. (VAM) and phosphate solubilizing bacteria (PSB)

    African Journals Online (AJOL)

    User

    2013-09-18

    Sep 18, 2013 ... mycorrhiza (VAM), and phosphate solubilising bacteria (PSB) individually and in .... Two-way analysis of variance (ANOVA) was carried out at a 0.05 level of significance on the data and SPSS version 13.0 was used.

  17. Control of indigenous pathogenic bacteria in seafood

    DEFF Research Database (Denmark)

    Huss, Hans Henrik

    1997-01-01

    The pathogenic bacteria indigenous to the aquatic and general environment are listed. Their distribution in nature, prevalence in seafood and the possibilities for growth of these organisms in various types of products are outlined These data, combined with what is known regarding the epidemiology...

  18. Filamentous bacteria transport electrons over centimetre distances

    DEFF Research Database (Denmark)

    Pfeffer, Christian; Larsen, Steffen; Song, Jie

    2012-01-01

    across centimetre-wide zones. Here we present evidence that the native conductors are long, filamentous bacteria. They abounded in sediment zones with electric currents and along their length they contained strings with distinct properties in accordance with a function as electron transporters. Living...

  19. Halophilic and haloalkaliphilic sulfur-oxidizing bacteria

    NARCIS (Netherlands)

    Sorokin, D.Y.; Banciu, H.; Robertson, L.A.; Kuenen, J.G.; Muntyan, M.S.; Muyzer, G.; Rosenberg, E.; DeLong, F.; Delong, E.; Lory, S.; Stackebrandt, E.; Thompson, F.

    2013-01-01

    Chemotrophic sulfur-oxidizing bacteria (SOB) represent an important functional group of microorganisms responsible for the dark oxidation of reduced sulfur compounds generated by sulfidogens. Until recently, only a single genus of halophilic SOB (Halothiobacillus) has been described, and nothing was

  20. Identification of marine methanol-utilizing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, M; Iwaki, H; Kouno, K; Inui, T

    1980-01-01

    A taxonomical study of 65 marine methanol-utilizing bacteria is described. They were Gram-negative, non-spore-forming rods with a polar flagellum and had marine bacterial properties and required vitamin B/sub 12/ for growth. All of them assimilated fructose in addition to C/sub 1/-compounds and produced acid oxidatively from fructose. Twenty-four strains assimilated only C/sub 1/-compounds. They were resistant to penicillin, oxytetracycline and 0/129 substance (Vibrio stat), and tolerant to 12% NaCl. Guanine-cytosine contents of deoxyribonucleic acid in typical strains fell in the range of 43.8 to 47.6%. Other morphological and physiological properties were almost the same as those of terrestrial methanol-utilizers. Bacteria in the first group (41 strains) were facultative methylotrophs and were divided into three subgroups by the assimilation of methylated amines, that is, subgroup I (30 strains) assimilated mono-, di- and tri-methylamine, subgroup II (9 strains) assimilated only mono-methylamine, the bacteria of subgroups I and II were named Alteromonas thalassomethanolica sp. nov. and subgroup III (2 strains) did not assimilate methylated amines, and was tentatively assigned as Alteromonas sp. The second group of bacteria (24 strains) was obligate methylotrophs, named Methylomonas thalassica sp. nov. and was divided into subgroup IV (15 strains) which assimilated mono-, di and tri-methylamine and subgroup V (9 strains) which assimilated mono-methylamine.

  1. Bacteria Isolated from Post-Partum Infections

    Directory of Open Access Journals (Sweden)

    Nahid Arianpour

    2009-06-01

    Full Text Available Objective: This study was undertaken with an aim to determine bacterial species involved in post partum infections and also their abundance in patients admitted to at Khanevadeh hospital. In this study out of three different kinds of postpartum infections (i.e. genital, breast and urinary tract, only genital infection is considered.Materials and Methods: Post partum infection among 6077 patients (inpatients and re-admitted patients of Khanevadeh hospital from 2003 till 2008 was studied in this descriptive study. Samples were collected from patients for laboratory diagnosis to find out the causative organisms.Results: Follow up of mothers after delivery revealed 7.59% (461 patients had post partum infection, out of which 1.03% (63 patients were re-hospitalized. Infection was more often among younger mothers. Bacteria isolated and identified were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora of the site of infection. Though, some pathogenic bacteria like Staphylococcus aureus, Neisseria gonorrhea, Chlamydia trachomatis,were also the causative agents. The commonest infection was infection at the site of episiotomy. Conclusion: Puerperal infection was detected in of 7.59% mothers. Bacteria isolated were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora. However; some pathogenic bacteria were isolated.

  2. Serpins in unicellular Eukarya, Archaea, and Bacteria:

    DEFF Research Database (Denmark)

    Roberts, T.H.; Hejgaard, Jørn; Saunders, N.F.W

    2004-01-01

    , where serpins were found in only 4 of 13 genera, and Bacteria, in only 9 of 56 genera. The serpins from unicellular organisms appear to be phylogenetically distinct from all of the clades of higher eukaryotic serpins. Most of the sequences from unicellular organisms have the characteristics...

  3. Bacteria as transporters of phosphorus through soil

    DEFF Research Database (Denmark)

    Glæsner, N.; Bælum, Jacob; Jacobsen, C. S.

    2016-01-01

    The transport of phosphorus (P) from agricultural land has led to the eutrophication of surface waters worldwide, especially in areas with intensive animal production. In this research, we investigated the role of bacteria in the leaching of P through three agricultural soils with different...

  4. Multidrug transporters in lactic acid bacteria

    NARCIS (Netherlands)

    Mazurkiewicz, P; Sakamoto, K; Poelarends, GJ; Konings, WN

    Gram-positive lactic acid bacteria possess several Multi-Drug Resistance systems (MDRs) that excrete out of the cell a wide variety of mainly cationic lipophilic cytotoxic compounds as well as many clinically relevant antibiotics. These MDRs are either proton/drug antiporters belonging to the major

  5. Drug efflux proteins in multidrug resistant bacteria

    NARCIS (Netherlands)

    vanVeen, HW; Konings, WN

    Bacteria contain an array of transport proteins in their cytoplasmic membrane. Many of these proteins play an important role in conferring resistance to toxic compounds. The multidrug efflux systems encountered in prokaryotic cells are very similar to those observed in eukaryotic cells. Therefore, a

  6. Bioluminescent hydrocarbonclastic bacteria of the Niger Delta ...

    African Journals Online (AJOL)

    Utilization of three petroleum hydrocarbons (Mobil SAE 40 Engine Oil, Diesel and Bonny light Crude Oil) by four bioluminescent bacteria (Vibrio harveyi, V. fisheri, Photobacterium leiognathi and P. Phosphoreum isolated from the Bonny estuary in the Niger Delta, Nigeria was investigated. Microbial utilization was monitored ...

  7. Pathomorphology and aerobic bacteria associated with pneumonia ...

    African Journals Online (AJOL)

    Pneumonia occurs in all ages of sheep and goats, in all breeds, in every country of the world causing heavy economic losses. The aim of this study was to determine the prevalence of pneumonia and aerobic bacteria flora associated with it in small ruminants slaughtered at the Nsukka abattoir. Pneumonic lung of small ...

  8. Metabolic plasticity for isoprenoid biosynthesis in bacteria.

    Science.gov (United States)

    Pérez-Gil, Jordi; Rodríguez-Concepción, Manuel

    2013-05-15

    Isoprenoids are a large family of compounds synthesized by all free-living organisms. In most bacteria, the common precursors of all isoprenoids are produced by the MEP (methylerythritol 4-phosphate) pathway. The MEP pathway is absent from archaea, fungi and animals (including humans), which synthesize their isoprenoid precursors using the completely unrelated MVA (mevalonate) pathway. Because the MEP pathway is essential in most bacterial pathogens (as well as in the malaria parasites), it has been proposed as a promising new target for the development of novel anti-infective agents. However, bacteria show a remarkable plasticity for isoprenoid biosynthesis that should be taken into account when targeting this metabolic pathway for the development of new antibiotics. For example, a few bacteria use the MVA pathway instead of the MEP pathway, whereas others possess the two full pathways, and some parasitic strains lack both the MVA and the MEP pathways (probably because they obtain their isoprenoids from host cells). Moreover, alternative enzymes and metabolic intermediates to those of the canonical MVA or MEP pathways exist in some organisms. Recent work has also shown that resistance to a block of the first steps of the MEP pathway can easily be developed because several enzymes unrelated to isoprenoid biosynthesis can produce pathway intermediates upon spontaneous mutations. In the present review, we discuss the major advances in our knowledge of the biochemical toolbox exploited by bacteria to synthesize the universal precursors for their essential isoprenoids.

  9. Chitinolytic bacteria of the mammal digestive tract

    Czech Academy of Sciences Publication Activity Database

    Šimůnek, Jiří; Hodrová, Blanka; Bartoňová, H.; Kopečný, Jan

    2001-01-01

    Roč. 46, č. 1 (2001), s. 76-78 ISSN 0015-5632 R&D Projects: GA ČR GA525/00/0984; GA AV ČR KSK5052113 Keywords : chitinolytic bacteria Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.776, year: 2001

  10. Tolerance of anaerobic bacteria to chlorinated solvents.

    Science.gov (United States)

    Koenig, Joanna C; Groissmeier, Kathrin D; Manefield, Mike J

    2014-01-01

    The aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (CAHs), perchloroethene (PCE), carbon tetrachloride (CT), chloroform (CF) and 1,2-dichloroethane (1,2-DCA), on the growth of eight anaerobic bacteria: four fermentative species (Escherichia coli, Klebsiella sp., Clostridium sp. and Paenibacillus sp.) and four respiring species (Pseudomonas aeruginosa, Geobacter sulfurreducens, Shewanella oneidensis and Desulfovibrio vulgaris). Effective concentrations of solvents which inhibited growth rates by 50% (EC50) were determined. The octanol-water partition coefficient or log Po/w of a CAH proved a generally satisfactory measure of its toxicity. Most species tolerated approximately 3-fold and 10-fold higher concentrations of the two relatively more polar CAHs CF and 1,2-DCA, respectively, than the two relatively less polar compounds PCE and CT. EC50 values correlated well with growth rates observed in solvent-free cultures, with fast-growing organisms displaying higher tolerance levels. Overall, fermentative bacteria were more tolerant to CAHs than respiring species, with iron- and sulfate-reducing bacteria in particular appearing highly sensitive to CAHs. These data extend the current understanding of the impact of CAHs on a range of anaerobic bacteria, which will benefit the field of bioremediation.

  11. The proteolytic systems of lactic acid bacteria

    NARCIS (Netherlands)

    Kunji, Edmund R.S.; Mierau, Igor; Hagting, Anja; Poolman, Bert; Konings, Wil N.

    1996-01-01

    Proteolysis in dairy lactic acid bacteria has been studied in great detail by genetic, biochemical and ultrastructural methods. From these studies the picture emerges that the proteolytic systems of lactococci and lactobacilli are remarkably similar in their components and mode of action. The

  12. Proteolytic enzymes of lactic acid bacteria

    NARCIS (Netherlands)

    Law, J; Haandrikman, A

    The proteolytic system of lactic acid bacteria is essential for their growth in milk and contributes significantly to flavour development in fermented milk products where these microorganisms are used as starter cultures. The proteolytic system is composed of proteinases which initially cleave the

  13. Biological Potential of Chitinolytic Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara Skøtt; Andersen, Birgitte; Gram, Lone

    2016-01-01

    Chitinolytic microorganisms secrete a range of chitin modifying enzymes, which can be exploited for production of chitin derived products or as fungal or pest control agents. Here, we explored the potential of 11 marine bacteria (Pseudoalteromonadaceae, Vibrionaceae) for chitin degradation using...

  14. Exopolysaccharides produced by lactic acid bacteria

    NARCIS (Netherlands)

    Caggianiello, Graziano; Kleerebezem, Michiel; Spano, Giuseppe

    2016-01-01

    A wide range of lactic acid bacteria (LAB) is able to produce capsular or extracellular polysaccharides, with various chemical compositions and properties. Polysaccharides produced by LAB alter the rheological properties of the matrix in which they are dispersed, leading to typically viscous and

  15. Radiographic markers - A reservoir for bacteria?

    International Nuclear Information System (INIS)

    Tugwell, Jenna; Maddison, Adele

    2011-01-01

    Introduction: Amongst the most frequently handled objects in the radiology department are radiographic markers. They are personal accessories used with every patient, and are kept in the radiographers pockets when not utilised. Upon enquiry it was discovered that many radiographers disregarded the potential of these accessories to become a vector for cross-contamination thus never or rarely clean them. The aims of this study were therefore to identify if radiographic markers are a reservoir for bacteria and to establish an effective cleaning method for decontaminating them. Methodology: 25 radiographers/student radiographers were selected for this study. Swabbing of their markers prior and post cleaning took place. The microbiology laboratory subsequently analyzed the results by quantifying and identifying the bacteria present. The participants also completed a closed questionnaire regarding their markers (e.g. frequency of cleaning and type of marker) to help specify the results gained from the swabbing procedure. Results: From the sample swabbed, 92% were contaminated with various organisms including Staphylococcus and Bacillus species, the amount of bacteria present ranged from 0 to >50 CFU. There were no significant differences between disinfectant wipes and alcohol gel in decontaminating the markers. Both successfully reduced their bacterial load, with 80% of the markers post cleaning having 0 CFU. Conclusion: The results indicated that radiographic markers can become highly contaminated with various organisms thus serve as a reservoir for bacteria. In addition, the markers need to be cleaned on a regular basis, with either disinfectant wipes or alcohol gel to reduce their bacterial load.

  16. Heterotrophic bacteria associated with the green alga

    NARCIS (Netherlands)

    Ismail, A.; Ktari, L.; Ahmed, M.; Bolhuis, H.; Bouhaouala-Zahar, B.; Stal, L.J.; Boudabbous, A.; El Bour, M.

    2018-01-01

    Heterotrophic bacteria associated with the green alga Ulva rigida, collected from the coast of Tunisia, were isolated andsubsequently identified by their 16S rRNA gene sequences and by phylogenetic analysis. The 71 isolates belong to four phyla:Proteobacteria (Alpha-and Gamma- subclasses),

  17. Influence of the Biliary System on Biliary Bacteria Revealed by Bacterial Communities of the Human Biliary and Upper Digestive Tracts.

    Directory of Open Access Journals (Sweden)

    Fuqiang Ye

    Full Text Available Biliary bacteria have been implicated in gallstone pathogenesis, though a clear understanding of their composition and source is lacking. Moreover, the effects of the biliary environment, which is known to be generally hostile to most bacteria, on biliary bacteria are unclear. Here, we investigated the bacterial communities of the biliary tract, duodenum, stomach, and oral cavity from six gallstone patients by using 16S rRNA amplicon sequencing. We found that all observed biliary bacteria were detectable in the upper digestive tract. The biliary microbiota had a comparatively higher similarity with the duodenal microbiota, versus those of the other regions, but with a reduced diversity. Although the majority of identified bacteria were greatly diminished in bile samples, three Enterobacteriaceae genera (Escherichia, Klebsiella, and an unclassified genus and Pyramidobacter were abundant in bile. Predictive functional analysis indicated enhanced abilities of environmental information processing and cell motility of biliary bacteria. Our study provides evidence for the potential source of biliary bacteria, and illustrates the influence of the biliary system on biliary bacterial communities.

  18. The interaction of bacteria and metal surfaces

    International Nuclear Information System (INIS)

    Mansfeld, Florian

    2007-01-01

    This review discusses different examples for the interaction of bacteria and metal surfaces based on work reported previously by various authors and work performed by the author with colleagues at other institutions and with his graduate students at CEEL. Traditionally it has been assumed that the interaction of bacteria with metal surfaces always causes increased corrosion rates ('microbiologically influenced corrosion' (MIC)). However, more recently it has been observed that many bacteria can reduce corrosion rates of different metals and alloys in many corrosive environments. For example, it has been found that certain strains of Shewanella can prevent pitting of Al 2024 in artificial seawater, tarnishing of brass and rusting of mild steel. It has been observed that corrosion started again when the biofilm was killed by adding antibiotics. The mechanism of corrosion protection seems to be different for different bacteria since it has been found that the corrosion potential E corr became more negative in the presence of Shewanella ana and algae, but more positive in the presence of Bacillus subtilis. These findings have been used in an initial study of the bacterial battery in which Shewanella oneidensis MR-1 was added to a cell containing Al 2024 and Cu in a growth medium. It was found that the power output of this cell continuously increased with time. In the microbial fuel cell (MFC) bacteria oxidize the fuel and transfer electrons directly to the anode. In initial studies EIS has been used to characterize the anode, cathode and membrane properties for different operating conditions of a MFC that contained Shewanella oneidensis MR-1. Cell voltage (V)-current density (i) curves were obtained using potentiodynamic sweeps. The current output of a MFC has been monitored for different experimental conditions

  19. The interaction of bacteria and metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mansfeld, Florian [Corrosion and Environmental Effects Laboratory (CEEL), The Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-0241 (United States)

    2007-10-10

    This review discusses different examples for the interaction of bacteria and metal surfaces based on work reported previously by various authors and work performed by the author with colleagues at other institutions and with his graduate students at CEEL. Traditionally it has been assumed that the interaction of bacteria with metal surfaces always causes increased corrosion rates ('microbiologically influenced corrosion' (MIC)). However, more recently it has been observed that many bacteria can reduce corrosion rates of different metals and alloys in many corrosive environments. For example, it has been found that certain strains of Shewanella can prevent pitting of Al 2024 in artificial seawater, tarnishing of brass and rusting of mild steel. It has been observed that corrosion started again when the biofilm was killed by adding antibiotics. The mechanism of corrosion protection seems to be different for different bacteria since it has been found that the corrosion potential E{sub corr} became more negative in the presence of Shewanella ana and algae, but more positive in the presence of Bacillus subtilis. These findings have been used in an initial study of the bacterial battery in which Shewanella oneidensis MR-1 was added to a cell containing Al 2024 and Cu in a growth medium. It was found that the power output of this cell continuously increased with time. In the microbial fuel cell (MFC) bacteria oxidize the fuel and transfer electrons directly to the anode. In initial studies EIS has been used to characterize the anode, cathode and membrane properties for different operating conditions of a MFC that contained Shewanella oneidensis MR-1. Cell voltage (V) - current density (i) curves were obtained using potentiodynamic sweeps. The current output of a MFC has been monitored for different experimental conditions. (author)

  20. [Methanotrophic bacteria of acid sphagnum bogs].

    Science.gov (United States)

    Dedysh, S N

    2002-01-01

    Acid sphagnum bogs cover a considerable part of the territory of Russia and are an important natural source of biogenic methane, which is formed in their anaerobic layers. A considerable portion of this methane is consumed in the aerobic part of the bog profile by acidophilic methanotrophic bacteria, which comprise the methane filter of sphagnum bogs and decrease CH4 emission to the atmosphere. For a long time, these bacteria escaped isolation, which became possible only after the elucidation of the optimal conditions of their functioning in situ: pH 4.5 to 5.5; temperature, from 15 to 20 degrees C; and low salt concentration in the solution. Reproduction of these conditions and rejection of earlier used media with a high content of biogenic elements allowed methanotrophic bacteria of two new genera and species--Methylocella palustris and Methylocapsa acidophila--to be isolated from the peat of sphagnum bogs of the northern part of European Russia and West Siberia. These bacteria are well adapted to the conditions in cold, acid, oligotrophic sphagnum bogs. They grow in a pH range of 4.2-7.5 with an optimum at 5.0-5.5, prefer moderate temperatures (15-25 degrees C) and media with a low content of mineral salts (200-500 mg/l), and are capable of active nitrogen fixation. Design of fluorescently labeled 16S rRNA-targeted oligonucleotide probes for the detection of Methylocella palustris and Methylocapsa acidophila and their application to the analysis of sphagnum peat samples showed that these bacteria represent dominant populations of methanotrophs with a density of 10(5)-10(6) cells/g peat. In addition to Methylocella and Methylocapsa populations, one more abundant population of methanotrophs was revealed (10(6) cells/g peat), which were phylogenetically close to the genus Methylocystis.

  1. Anaerobic bacteria in wastewater treatment plant.

    Science.gov (United States)

    Cyprowski, Marcin; Stobnicka-Kupiec, Agata; Ławniczek-Wałczyk, Anna; Bakal-Kijek, Aleksandra; Gołofit-Szymczak, Małgorzata; Górny, Rafał L

    2018-03-28

    The objective of this study was to assess exposure to anaerobic bacteria released into air from sewage and sludge at workplaces from a wastewater treatment plant (WWTP). Samples of both sewage and sludge were collected at six sampling points and bioaerosol samples were additionally collected (with the use of a 6-stage Andersen impactor) at ten workplaces covering different stages of the technological process. Qualitative identification of all isolated strains was performed using the biochemical API 20A test. Additionally, the determination of Clostridium pathogens was carried out using 16S rRNA gene sequence analysis. The average concentration of anaerobic bacteria in the sewage samples was 5.49 × 10 4 CFU/mL (GSD = 85.4) and in sludge-1.42 × 10 6 CFU/g (GSD = 5.1). In turn, the average airborne bacterial concentration was at the level of 50 CFU/m 3 (GSD = 5.83) and the highest bacterial contamination (4.06 × 10 3  CFU/m 3 ) was found in winter at the bar screens. In total, 16 bacterial species were determined, from which the predominant strains belonged to Actinomyces, Bifidobacterium, Clostridium, Propionibacterium and Peptostreptococcus genera. The analysis revealed that mechanical treatment processes were responsible for a substantial emission of anaerobic bacteria into the air. In both the sewage and air samples, Clostridium perfringens pathogen was identified. Anaerobic bacteria were widely present both in the sewage and in the air at workplaces from the WWTP, especially when the technological process was performed in closed spaces. Anaerobic bacteria formed small aggregates with both wastewater droplets and dust particles of sewage sludge origin and as such may be responsible for adverse health outcomes in exposed workers.

  2. Antibacterial activity of silver-killed bacteria: the "zombies" effect

    Science.gov (United States)

    Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David

    2015-04-01

    We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.

  3. Endosymbiont-based immunity in Drosophila melanogaster against parasitic nematode infection.

    Science.gov (United States)

    Yadav, Shruti; Frazer, Joanna; Banga, Ashima; Pruitt, Katherine; Harsh, Sneh; Jaenike, John; Eleftherianos, Ioannis

    2018-01-01

    Associations between endosymbiotic bacteria and their hosts represent a complex ecosystem within organisms ranging from humans to protozoa. Drosophila species are known to naturally harbor Wolbachia and Spiroplasma endosymbionts, which play a protective role against certain microbial infections. Here, we investigated whether the presence or absence of endosymbionts affects the immune response of Drosophila melanogaster larvae to infection by Steinernema carpocapsae nematodes carrying or lacking their mutualistic Gram-negative bacteria Xenorhabdus nematophila (symbiotic or axenic nematodes, respectively). We find that the presence of Wolbachia alone or together with Spiroplasma promotes the survival of larvae in response to infection with S. carpocapsae symbiotic nematodes, but not against axenic nematodes. We also find that Wolbachia numbers are reduced in Spiroplasma-free larvae infected with axenic compared to symbiotic nematodes, and they are also reduced in Spiroplasma-containing compared to Spiroplasma-free larvae infected with axenic nematodes. We further show that S. carpocapsae axenic nematode infection induces the Toll pathway in the absence of Wolbachia, and that symbiotic nematode infection leads to increased phenoloxidase activity in D. melanogaster larvae devoid of endosymbionts. Finally, infection with either type of nematode alters the metabolic status and the fat body lipid droplet size in D. melanogaster larvae containing only Wolbachia or both endosymbionts. Our results suggest an interaction between Wolbachia endosymbionts with the immune response of D. melanogaster against infection with the entomopathogenic nematodes S. carpocapsae. Results from this study indicate a complex interplay between insect hosts, endosymbiotic microbes and pathogenic organisms.

  4. Lactic acid bacteria affect serum cholesterol levels, harmful fecal enzyme activity, and fecal water content

    OpenAIRE

    Chung Myung; Shin Hea; Lee Kyung; Kim Mi; Baek Eun; Jang Seok; Lee Do; Kim Jin; Lee Kang; Ha Nam

    2009-01-01

    Abstract Background Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content. Methods In vitro culture experiments were performed to ...

  5. A nanovehicle developed for treating deep-seated bacteria using low-dose X-ray.

    Science.gov (United States)

    Pan, Chien-Lin; Chen, Ming-Hong; Tung, Fu-I; Liu, Tse-Ying

    2017-01-01

    Many non-antibiotic strategies, such as photocatalysis and photodynamic therapy, have been proposed to inhibit and/or kill bacteria. However, these approaches still have drawbacks such as insufficient bacterial specificity and the limited penetration depth of ultraviolet and near-infrared light. To overcome these limitations, we developed a bacteria-specific anti-bacterial technique via using low-dose X-ray. Graphene oxide quantum dots (GQDs, a multifunctional vehicle) conjugated with vancomycin (Van, a bacteria-targeting ligand) were assembled with Protoporphyrin IX (PpIX, a photo/radiation sensitizer) to yield a novel Van-GQDs/PpIX complex that specifically attached to Escherichia coli and efficiently generated intracellular reactive oxygen species following X-ray activation. Delivery using GQDs increased the PpIX/Van ratio in the target bacterial cell, damaged bacterial cell wall, and enhanced X-ray-induced PpIX activation. Hence, this approach allowed for the use of a low-dose X-ray to efficiently activate the Van-GQDs/PpIX complex to exert its bactericidal effects on Escherichia coli without damaging normal cells. Furthermore, the E. coli did not develop resistance to the proposed approach for at least 7 rounds of repeated administration during one week. Thus, this proposed vehicle exhibiting bacteria-specific X-ray-triggered toxicity is a promising alternative to antibiotics for treating serious bacterial infections occurring in deep-seated tissues/organs (e.g., osteomyelitis and peritonitis). Administration of antibiotics is the most common treatment modality for bacterial infections. However, in some cases, patient attributes such as age, health, tolerance to antibiotics do not allow for the use of high-dose antibiotics. In addition, some bacteria develop resistance to antibiotics because of improper and long-term use of these agents. Therefore, non-antibiotic strategies to treat deeply situated bacterial infections, such as osteomyelitis, are urgently

  6. Interactions between Paramyxoviruses and Bacteria: Implications for Pathogenesis and Intervention

    NARCIS (Netherlands)

    D.T. Nguyen (Tien)

    2014-01-01

    markdownabstract__Abstract__ Globally, respiratory tract diseases caused by bacteria and viruses are an important burden of disease. Respiratory bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus) can colonize the upper respiratory tract.

  7. Time related total lactic acid bacteria population diversity and ...

    African Journals Online (AJOL)

    user

    2011-02-07

    Feb 7, 2011 ... the diversity and dynamics of lactic acid bacteria (LAB) population in fresh ..... combining morphological, biochemical and molecular data are important for ..... acid bacteria from fermented maize (Kenkey) and their interactions.

  8. Oh What a Tangled Biofilm Web Bacteria Weave

    Science.gov (United States)

    ... Home Page Oh What a Tangled Biofilm Web Bacteria Weave By Elia Ben-Ari Posted May 1, ... a suitable surface, some water and nutrients, and bacteria will likely put down stakes and form biofilms. ...

  9. Developing new bacteria subroutines in the SWAT model

    Science.gov (United States)

    Fecal bacteria observations from four different sites in Korea and the US demonstrate seasonal variability, showing a significant relationship with temperature (Figure 1); fecal indicator bacteria (FIB) concentrations are relatively higher in summer and lower in winter , including Stillwater river (...

  10. Bacteria Associated with Fresh Tilapia Fish (Oreochromis niloticus ...

    African Journals Online (AJOL)

    acer

    Keywords: Bacteria, Tilapia fish and Sokoto central market. INTRODUCTION ... The bacteria are transmitted by fish that have made contact ... with which a product spoils is also related to the .... Base on the percentage frequency of occurance ,.

  11. Frequency of Resistance and Susceptible Bacteria Isolated from Houseflies

    Directory of Open Access Journals (Sweden)

    B Davari

    2010-12-01

    Conclusion: Houseflies collected from hospitals and slaughterhouse may be involved in the spread of drug resistant bacteria and may increase the potential of human exposure to drug resistant bacteria.

  12. Have sex or not? Lessons from bacteria.

    Science.gov (United States)

    Lodé, T

    2012-01-01

    Sex is one of the greatest puzzles in evolutionary biology. A true meiotic process occurs only in eukaryotes, while in bacteria, gene transcription is fragmentary, so asexual reproduction in this case really means clonal reproduction. Sex could stem from a signal that leads to increased reproductive output of all interacting individuals and could be understood as a secondary consequence of primitive metabolic reactions. Meiotic sex evolved in proto-eukaryotes to solve a problem that bacteria did not have, namely a large amount of DNA material, occurring in an archaic step of proto-cell formation and genetic exchanges. Rather than providing selective advantages through reproduction, sex could be thought of as a series of separate events which combines step-by-step some very weak benefits of recombination, meiosis, gametogenesis and syngamy. Copyright © 2012 S. Karger AG, Basel.

  13. Mucosal immunity to pathogenic intestinal bacteria.

    Science.gov (United States)

    Perez-Lopez, Araceli; Behnsen, Judith; Nuccio, Sean-Paul; Raffatellu, Manuela

    2016-03-01

    The intestinal mucosa is a particularly dynamic environment in which the host constantly interacts with trillions of commensal microorganisms, known as the microbiota, and periodically interacts with pathogens of diverse nature. In this Review, we discuss how mucosal immunity is controlled in response to enteric bacterial pathogens, with a focus on the species that cause morbidity and mortality in humans. We explain how the microbiota can shape the immune response to pathogenic bacteria, and we detail innate and adaptive immune mechanisms that drive protective immunity against these pathogens. The vast diversity of the microbiota, pathogens and immune responses encountered in the intestines precludes discussion of all of the relevant players in this Review. Instead, we aim to provide a representative overview of how the intestinal immune system responds to pathogenic bacteria.

  14. Ancient bacteria show evidence of DNA repair

    DEFF Research Database (Denmark)

    Johnson, Sarah Stewart; Hebsgaard, Martin B; Christensen, Torben R

    2007-01-01

    -term survival of bacteria sealed in frozen conditions for up to one million years. Our results show evidence of bacterial survival in samples up to half a million years in age, making this the oldest independently authenticated DNA to date obtained from viable cells. Additionally, we find strong evidence...... geological timescales. There has been no direct evidence in ancient microbes for the most likely mechanism, active DNA repair, or for the metabolic activity necessary to sustain it. In this paper, we couple PCR and enzymatic treatment of DNA with direct respiration measurements to investigate long...... that this long-term survival is closely tied to cellular metabolic activity and DNA repair that over time proves to be superior to dormancy as a mechanism in sustaining bacteria viability....

  15. Protein-Injection Machines in Bacteria.

    Science.gov (United States)

    Galán, Jorge E; Waksman, Gabriel

    2018-03-08

    Many bacteria have evolved specialized nanomachines with the remarkable ability to inject multiple bacterially encoded effector proteins into eukaryotic or prokaryotic cells. Known as type III, type IV, and type VI secretion systems, these machines play a central role in the pathogenic or symbiotic interactions between multiple bacteria and their eukaryotic hosts, or in the establishment of bacterial communities in a diversity of environments. Here we focus on recent progress elucidating the structure and assembly pathways of these machines. As many of the interactions shaped by these machines are of medical importance, they provide an opportunity to develop novel therapeutic approaches to combat important human diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Seeing Streptococcus pneumoniae, a Common Killer Bacteria

    DEFF Research Database (Denmark)

    Kjærgaard, Rikke Schmidt; Andersen, Ebbe Sloth

    2014-01-01

    Look around you. The diversity and complexity of life on earth is overwhelming and data continues to grow. In our desire to understand and explain everything scientifically from molecular evolution to supernovas we depend on visual representations. This paper investigates visual representations...... of the bacteria Streptococcus pneumoniae by use of ink, watercolours and computer graphics. We propose a novel artistic visual rendering of Streptococcus pneumoniae and ask what the value of these kind of representations are compared to traditional scientific data. We ask if drawings and computer......-assisted representations can add to our scientific knowledge about this dangerous bacteria. Is there still a role for the scientific illustrator in the scientific process and synthesis of scientific knowledge?...

  17. [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.

  18. Tip enhancement

    CERN Document Server

    Kawata, Satoshi

    2007-01-01

    This book discusses the recent advances in the area of near-field Raman scattering, mainly focusing on tip-enhanced and surface-enhanced Raman scattering. Some of the key features covered here are the optical structuring and manipulations, single molecule sensitivity, analysis of single-walled carbon nanotubes, and analytic applications in chemistry, biology and material sciences. This book also discusses the plasmonic materials for better enhancement, and optical antennas. Further, near-field microscopy based on second harmonic generation is also discussed. Chapters have been written by some of the leading scientists in this field, who present some of their recent work in this field.·Near-field Raman scattering·Tip-enhanced Raman spectroscopy·Surface-enhanced Raman spectroscopy·Nano-photonics·Nanoanalysis of Physical, chemical and biological materials beyond the diffraction limits·Single molecule detection

  19. New Insight on the Response of Bacteria to Fluoride

    OpenAIRE

    Breaker, R.R.

    2012-01-01

    Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biolog...

  20. Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

    OpenAIRE

    Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, Rui

    2014-01-01

    This article belongs to the Special Issue Selected Papers from the 14th International Symposium on Marine Natural Products Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S...

  1. Bactericidal effects of antibiotics on slowly growing and nongrowing bacteria.

    OpenAIRE

    Eng, R H; Padberg, F T; Smith, S M; Tan, E N; Cherubin, C E

    1991-01-01

    Antimicrobial agents are most often tested against bacteria in the log phase of multiplication to produce the maximum bactericidal effect. In an infection, bacteria may multiply less optimally. We examined the effects of several classes of antimicrobial agents to determine their actions on gram-positive and gram-negative bacteria during nongrowing and slowly growing phases. Only ciprofloxacin and ofloxacin exhibited bactericidal activity against nongrowing gram-negative bacteria, and no antib...

  2. [Application of anaerobic bacteria detection in oral and maxillofacial infection].

    Science.gov (United States)

    Bao, Zhen-ying; Lin, Qin; Meng, Yan-hong; He, Chun; Su, Jia-zeng; Peng, Xin

    2016-02-18

    To investigate the distribution and drug resistance of anaerobic bacteria in the patients with oral and maxillofacial infection. Aerobic and anaerobic bacteria cultures from 61 specimens of pus from the patients with oral and maxillofacial infection in the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology were identified. The culture type was evaluated by API 20A kit and drug resistance test was performed by Etest method. The clinical data and antibacterial agents for the treatment of the 61 cases were collected, and the final outcomes were recorded. The bacteria cultures were isolated from all the specimens, with aerobic bacteria only in 6 cases (9.8%), anaerobic bacteria only in 7 cases (11.5%), and both aerobic and anaerobic bacteria in 48 cases (78.7%). There were 55 infected cases (90.2%) with anaerobic bacteria, and 81 anaerobic bacteria stains were isolated. The highest bacteria isolation rate of Gram positive anaerobic bacteria could be found in Peptostreptococcus, Bifidobacterium and Pemphigus propionibacterium. No cefoxitin, amoxicillin/carat acid resistant strain was detected in the above three Gram positive anaerobic bacteria. The highest bacteria isolation rate of Gram negative anaerobic bacteria could be detected in Porphyromonas and Prevotella. No metronidazole, cefoxitin, amoxicillin/carat acid resistant strain was found in the two Gram negative anaerobic bacteria. In the study, 48 patients with oral and maxillofacial infection were treated according to the results of drug resistance testing, and the clinical cure rate was 81.3%. Mixed aerobic and anaerobic bacteria cultures are very common in most oral and maxillofacial infection patients. Anaerobic bacteria culture and drug resistance testing play an important role in clinical treatment.

  3. Characterization of nitrate-reducing and amino acid-using bacteria prominent in nitrotoxin-enriched equine cecal populations

    Science.gov (United States)

    In the present study, populations of equine cecal microbes enriched for enhanced rates of 3-nitro-1-propionic acid (NPA) or nitrate metabolism were diluted and cultured for NPA-metabolizing bacteria on a basal enrichment medium (BEM) or tryptose soy agar (TSA) medium supplemented with either 5 mM NP...

  4. Accelerated wound healing in mice by on-site production and delivery of CXCL12 by transformed lactic acid bacteria.

    Science.gov (United States)

    Vågesjö, Evelina; Öhnstedt, Emelie; Mortier, Anneleen; Lofton, Hava; Huss, Fredrik; Proost, Paul; Roos, Stefan; Phillipson, Mia

    2018-02-20

    Impaired wound closure is a growing medical problem associated with metabolic diseases and aging. Immune cells play important roles in wound healing by following instructions from the microenvironment. Here, we developed a technology to bioengineer the wound microenvironment and enhance healing abilities of the immune cells. This resulted in strongly accelerated wound healing and was achieved by transforming Lactobacilli with a plasmid encoding CXCL12. CXCL12-delivering bacteria administrated topically to wounds in mice efficiently enhanced wound closure by increasing proliferation of dermal cells and macrophages, and led to increased TGF-β expression in macrophages. Bacteria-produced lactic acid reduced the local pH, which inhibited the peptidase CD26 and consequently enhanced the availability of bioactive CXCL12. Importantly, treatment with CXCL12-delivering Lactobacilli also improved wound closure in mice with hyperglycemia or peripheral ischemia, conditions associated with chronic wounds, and in a human skin wound model. Further, initial safety studies demonstrated that the topically applied transformed bacteria exerted effects restricted to the wound, as neither bacteria nor the chemokine produced could be detected in systemic circulation. Development of drugs accelerating wound healing is limited by the proteolytic nature of wounds. Our technology overcomes this by on-site chemokine production and reduced degradation, which together ensure prolonged chemokine bioavailability that instructed local immune cells and enhanced wound healing. Copyright © 2018 the Author(s). Published by PNAS.

  5. Cellulase Production by Bacteria: A Review

    OpenAIRE

    Sadhu Sangrila; Maiti Tushar Kanti

    2013-01-01

    Cellulose is an abundant natural biopolymer on earth and most dominating Agricultural waste. This cellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. It can be degraded by cellulase produced by cellulolytic bacteria. This enzyme has various industrial applications and now considered as major group of industrial enzyme. The review discusses application of cellulase, classification of cellulase, quantification...

  6. Tumour targeting with systemically administered bacteria.

    LENUS (Irish Health Repository)

    Morrissey, David

    2012-01-31

    Challenges for oncology practitioners and researchers include specific treatment and detection of tumours. The ideal anti-cancer therapy would selectively eradicate tumour cells, whilst minimising side effects to normal tissue. Bacteria have emerged as biological gene vectors with natural tumour specificity, capable of homing to tumours and replicating locally to high levels when systemically administered. This property enables targeting of both the primary tumour and secondary metastases. In the case of invasive pathogenic species, this targeting strategy can be used to deliver genes intracellularly for tumour cell expression, while non-invasive species transformed with plasmids suitable for bacterial expression of heterologous genes can secrete therapeutic proteins locally within the tumour environment (cell therapy approach). Many bacterial genera have been demonstrated to localise to and replicate to high levels within tumour tissue when intravenously (IV) administered in rodent models and reporter gene tagging of bacteria has permitted real-time visualisation of this phenomenon. Live imaging of tumour colonising bacteria also presents diagnostic potential for this approach. The nature of tumour selective bacterial colonisation appears to be tumour origin- and bacterial species- independent. While originally a correlation was drawn between anaerobic bacterial colonisation and the hypoxic nature of solid tumours, it is recently becoming apparent that other elements of the unique microenvironment within solid tumours, including aberrant neovasculature and local immune suppression, may be responsible. Here, we consider the pre-clinical data supporting the use of bacteria as a tumour-targeting tool, recent advances in the area, and future work required to develop it into a beneficial clinical tool.

  7. Chemotactic waves of bacteria at the mesoscale

    OpenAIRE

    Calvez, Vincent

    2016-01-01

    The existence of travelling waves for a model of concentration waves of bacteria is investigated. The model consists in a kinetic equation for the biased motion of cells following a run-and-tumble process, coupled with two reaction-diffusion equations for the chemical signals. Strong mathematical difficulties arise in comparison with the diffusive regime which was studied in a previous work. The cornerstone of the proof consists in establishing monotonicity properties of the spatial density o...

  8. Light irradiation helps magnetotactic bacteria eliminate intracellular reactive oxygen species.

    Science.gov (United States)

    Li, Kefeng; Wang, Pingping; Chen, Chuanfang; Chen, Changyou; Li, Lulu; Song, Tao

    2017-09-01

    Magnetotactic bacteria (MTB) demonstrate photoresponse. However, little is known about the biological significance of this behaviour. Magnetosomes exhibit peroxidase-like activity and can scavenge reactive oxygen species (ROS). Magnetosomes extracted from the Magnetospirillum magneticum strain AMB-1 show enhanced peroxidase-like activity under illumination. The present study investigated the effects of light irradiation on nonmagnetic (without magnetosomes) and magnetic (with magnetosomes) AMB-1 cells. Results showed that light irradiation did not affect the growth of nonmagnetic and magnetic cells but significantly increased magnetosome synthesis and reduced intracellular ROS level in magnetic cells. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to analyse the expression level of magnetosome formation-associated genes (mamA, mms6, mms13 and mmsF) and stress-related genes (recA, oxyR, SOD, amb0664 and amb2684). Results showed that light irradiation upregulated the expression of mms6, mms13 and mmsF. Furthermore, light irradiation upregulated the expression of stress-related genes in nonmagnetic cells but downregulated them in magnetic cells. Additionally, magnetic cells exhibited stronger phototactic behaviour than nonmagnetic ones. These results suggested that light irradiation could heighten the ability of MTB to eliminate intracellular ROS and help them adapt to lighted environments. This phenomenon may be related to the enhanced peroxidase-like activity of magnetosomes under light irradiation. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  9. Interaction of surfactant-modified zeolites and phosphate accumulating bacteria

    International Nuclear Information System (INIS)

    Hrenovic, J.; Rozic, M.; Sekovanic, L.; Anic-Vucinic, A.

    2008-01-01

    The aim of this study was to determine the interaction of surfactant-modified zeolites (SMZ) and orthophosphate (P)-accumulating bacteria in the process of P removal from wastewater. The SMZ were prepared from the natural zeolite (NZ) of size fractions <0.122 mm and 0.25-0.5 mm. The hexadecyltrimethylammonium (HDTMA) bromide was used to modify the NZ surface from partial monolayer to the bilayer coverage. The surface modification of NZ resulted in the change of zeta potential of particles from negative to positive and great enhancement of the P-adsorption capacity. Only in reactors containing <0.122 mm fraction of partial monolayer coverage of the SMZ, the P was efficiently removed from wastewater by combined adsorption onto the SMZ and bacterial uptake in the biomass. The SMZ with bilayer or patchy bilayer coverage showed the bactericidal effect. To enhance the P removal from wastewater in the aerated biological system, the SMZ can be used, but the special attention should be given to the configuration of sorbed HDTMA molecules and its potential desorption

  10. Isolation and identification of bacteria to improve the strength of concrete.

    Science.gov (United States)

    Krishnapriya, S; Venkatesh Babu, D L; G, Prince Arulraj

    2015-05-01

    The objective of this research work is to isolate and identify calcite precipitating bacteria and to check the suitability of these bacteria for use in concrete to improve its strength. Bacteria to be incorporated in concrete should be alkali resistant to endure the high pH of concrete and endospore forming to withstand the mechanical stresses induced in concrete during mixing. They must exhibit high urease activity to precipitate calcium carbonate in the form of calcite. Bacterial strains were isolated from alkaline soil samples of a cement factory and were tested for urease activity, potential to form endospores and precipitation of calcium carbonate. Based on these results, three isolates were selected and identified by 16S rRNA gene sequencing. They were identified as Bacillus megaterium BSKAU, Bacillus licheniformis BSKNAU and Bacillus flexus BSKNAU. The results were compared with B. megaterium MTCC 1684 obtained from Microbial Type Culture Collection and Gene Bank, Chandigarh, India. Experimental work was carried out to assess the influence of bacteria on the compressive strength and tests revealed that bacterial concrete specimens showed enhancement in compressive strength. The efficiency of bacteria toward crack healing was also tested. Substantial increase in strength and complete healing of cracks was observed in concrete specimens cast with B. megaterium BSKAU, B. licheniformis BSKNAU and B. megaterium MTCC 1684. This indicates the suitability of these bacterial strains for use in concrete. The enhancement of strength and healing of cracks can be attributed to the filling of cracks in concrete by calcite which was visualized by scanning electron microscope. Copyright © 2015 Elsevier GmbH. All rights reserved.

  11. Transfer of DNA from Bacteria to Eukaryotes

    Directory of Open Access Journals (Sweden)

    Benoît Lacroix

    2016-07-01

    Full Text Available Historically, the members of the Agrobacterium genus have been considered the only bacterial species naturally able to transfer and integrate DNA into the genomes of their eukaryotic hosts. Yet, increasing evidence suggests that this ability to genetically transform eukaryotic host cells might be more widespread in the bacterial world. Indeed, analyses of accumulating genomic data reveal cases of horizontal gene transfer from bacteria to eukaryotes and suggest that it represents a significant force in adaptive evolution of eukaryotic species. Specifically, recent reports indicate that bacteria other than Agrobacterium, such as Bartonella henselae (a zoonotic pathogen, Rhizobium etli (a plant-symbiotic bacterium related to Agrobacterium, or even Escherichia coli, have the ability to genetically transform their host cells under laboratory conditions. This DNA transfer relies on type IV secretion systems (T4SSs, the molecular machines that transport macromolecules during conjugative plasmid transfer and also during transport of proteins and/or DNA to the eukaryotic recipient cells. In this review article, we explore the extent of possible transfer of genetic information from bacteria to eukaryotic cells as well as the evolutionary implications and potential applications of this transfer.

  12. Intracellular bacteria: the origin of dinoflagellate toxicity.

    Science.gov (United States)

    Silva, E S

    1990-01-01

    Dinoflagellate blooms of the same species have been registered either as toxic or nontoxic and, in the latter case, toxicity may be of different types. A hypothesis has been formulated according to which the bacteria having in some way taken part in the toxin formation are either inside the dinoflagellate cell or in the nutritive liquid. The presence of intracellular bacteria in those microorganisms has been studied mainly in material from cultures, a few from the sea, and several strains were isolated from different species. Experiments with crossed inoculations have shown that the bacterial strain from Gonyaulax tamarensis caused the cells of some other species to become toxic. From nontoxic clonal cultures of Prorocentrum balticum, Glenodinium foliaceum, and Gyrodinium instriatum, after inoculation of that bacterial strain, cultures were obtained whose cell extracts showed the same kind of toxicity as G. tamarensis. No toxic action could be found in the extracts of the bacterial cells form the assayed strains. The interference of intracellular bacteria in the metabolism of dinoflagellates must be the main cause of their toxicity.

  13. Acoustic manipulation of bacteria cells suspensions

    Science.gov (United States)

    GutiéRrez-Ramos, Salomé; Hoyos, Mauricio; Aider, Jean Luc; Ruiz, Carlos; Acoustofluidics Team Team; Soft; Bio Group Collaboration

    An acoustic contacless manipulation gives advantages in the exploration of the complex dynamics enviroment that active matter exhibits. Our works reports the control confinement and dispersion of Escherichia coliRP437-pZA3R-YFP suspensions (M9Glu-Ca) via acoustic levitation.The manipulation of the bacteria bath in a parallel plate resonator is achieved using the acoustic radiation force and the secondary radiation force. The primary radiation force generates levitation of the bacteria cells at the nodal plane of the ultrasonic standing wave generated inside the resonator. On the other side, secondary forces leads to the consolidation of stable aggregates. All the experiments were performed in the acoustic trap described, where we excite the emission plate with a continuous sinusoidal signal at a frequency in the order of MHz and a quartz slide as the reflector plate. In a typical experiment we observed that, before the input of the signal, the bacteria cells exhibit their typical run and tumble behavior and after the sound is turned on all of them displace towards the nodal plane, and instantaneously the aggregation begins in this region. CNRS French National Space Studies, CONACYT Mexico.

  14. Fecal indicator bacteria at Havana Bay

    International Nuclear Information System (INIS)

    Lopez Perez, Lisse; Gomez D'Angelo, Yamiris; Beltran Gonzalez, Jesus; Alvarez Valiente, Reinaldo

    2013-01-01

    Aims: Fecal indicator bacteria concentrations were evaluated in Havana Bay. Methods: Concentrations of traditional fecal indicator bacteria were calculated between April 2010 and February 2011, by MPN methods. Concentrations of thermo tolerant coliform (CTT), Escherichia coli, fecal streptococci (EF), intestinal enterococci (ENT) in seawater, and Clostridium perfringens in sediment surface, were determined. Results: CTT and E. coli levels were far above Cuban water quality standard for indirect contact with water, showing the negative influence of sewage and rivers on the bay. The EF and ENT were measured during sewage spills at the discharge site and they were suitable indicators of fecal contamination, but these indicators didn't show the same behavior in other selected sites. This result comes from its well-known inactivation by solar light in tropical zones and the presumable presence of humid acids in the waters of the bay. Conclusion: Fecal indicator bacteria and its statistical relationships reflect recent and chronic fecal contamination at the bay and near shores.

  15. Alkaline phosphatase activity of rumen bacteria.

    Science.gov (United States)

    Cheng, K J; Costerton, J W

    1977-11-01

    Of the 54 strains of rumen bacteria examined for alkaline phosphatase (APase) production, 9 of 33 gram-negative strains and none of 21 gram-positive strains produced the enzyme. The APase of the cells of the three strains of Bacteroides ruminicola that produced significant amounts of the enzyme was located in the periplasmic area of the cell envelope, whereas the enzyme was located in the strains of Selenomonas ruminantium and Succinivibrio dextrinosolvens was associated with the outer membrane. The localization of APase production in the cells of natural populations of rumen bacteria from hay-fed sheep was accomplished by reaction product deposition, and both the proportion of APase-producing bacteria and the location of the enzyme in the cell envelope of the producing cells could be determined. We suggest that this procedure is useful in detecting shifts in the bacterial population and the release of cell-bound APase that accompany feedlot bloat and other sequelae of dietary manipulation in ruminants.

  16. Soil bacteria for remediation of polluted soils

    Energy Technology Data Exchange (ETDEWEB)

    Springael, D; Bastiaens, L; Carpels, M; Mergaey, M; Diels, L

    1996-09-18

    Soil bacteria, specifically adapted to contaminated soils, may be used for the remediation of polluted soils. The Flemish research institute VITO has established a collection of bacteria, which were isolated from contaminated areas. This collection includes microbacteria degrading mineral oils (Pseudomonas sp., Acinetobacter sp. and others), microbacteria degrading polycyclic aromatic hydrocarbons (genera Sphingomonas and Mycobacterium), microbacteria degrading polychlorobiphenyls (genus Ralstonia and strains related to beta-Proteobacteria), and metal resistant bacteria with plasmid borne resistances to Cd, Zn, Ni, Co, Cu, Hg, and Cr. Bench-scale reactors were developed to investigate the industrial feasibility of bioremediation. Batch Stirred Tank Reactors were used to evaluate the efficiency of oil degraders. Soils, contaminated with non-ferrous metals, were treated using a Bacterial Metal Slurry Reactor. It was found that the reduction of the Cd concentration may vary strongly from sample to sample: reduction factors vary from 95 to 50%. Is was shown that Cd contained in metallic sinter and biologically unavailable Cd could not be removed.

  17. Magnesium and manganese content of halophilic bacteria

    International Nuclear Information System (INIS)

    de Medicis, E.; Paquette, J.; Gauthier, J.J.; Shapcott, D.

    1986-01-01

    Magnesium and manganese contents were measured by atomic absorption spectrophotometry in bacteria of several halophilic levels, in Vibrio costicola, a moderately halophilic eubacterium growing in 1 M NaCl, Halobacterium volcanii, a halophilic archaebacterium growing in 2.5 NaCl, Halobacterium cutirubrum, an extremely halophilic archaebacterium growing in 4 M NaCl, and Escherichia coli, a nonhalophilic eubacterium growing in 0.17 M NaCl. Magnesium and manganese contents varied with the growth phase, being maximal at the early log phase. Magnesium and manganese molalities in cell water were shown to increase with the halophilic character of the logarithmically growing bacteria, from 30 mmol of Mg per kg of cell water and 0.37 mmol of Mn per kg of cell water for E. coli to 102 mmol of Mg per kg of cell water and 1.6 mmol of Mn per kg of cell water for H cutirubrum. The intracellular concentrations of manganese were determined independently by a radioactive tracer technique in V. costicola and H. volcanii. The values obtained by 54 Mn loading represented about 70% of the values obtained by atomic absorption. The increase of magnesium and manganese contents associated with the halophilic character of the bacteria suggests that manganese and magnesium play a role in haloadaptation

  18. Fish skin bacteria: Colonial and cellular hydrophobicity.

    Science.gov (United States)

    Sar, N; Rosenberg, E

    1987-05-01

    Bacteria were desorbed from the skin of healthy, fast-swimming fish by several procedures, including brief exposure to sonic oscillation and treatment with nontoxic surface active agents. The surface properties of these bacteria were studied by measuring their adhesion to hexadecane, as well as by a newly developed, simple method for studying the hydrophobicity of bacterial lawns. This method, referred to as the "Direction of Spreading" (DOS) method, consists of recording the direction to which a water drop spreads when introduced at the border between bacterial lawns and other surfaces. Of the 13 fish skin isolates examined, two strains were as hydrophobic as polystyrene by the DOS method. Suspended cells of one of these strains adhered strongly to hexadecane (84%), whereas cells of the other strain adhered poorly (13%). Another strain which was almost as hydrophobic as polystyrene by the DOS method did not adhere to hexadecane at all. Similarly, lawns of three other strains were more hydrophobic than glass by the DOS method, but cell suspensions prepared from these colonies showed little or no adhesion to hexadecane. The high colonial but relatively low cellular hydrophobicity could be due to a hydrophobic slime that is removed during the suspension and washing procedures. The possibility that specific bacteria assist in fish locomotion by changing the surface properties of the fish skin and by producing drag-reducing polymers is discussed.

  19. Contaminant bacteria in traditional-packed honey

    Directory of Open Access Journals (Sweden)

    Hening Tjaturina Pramesti

    2007-03-01

    Full Text Available Honey may be contaminated by microorganisms during its harvesting, processing, and packaging. Honey selected for clinical purposes must safe, sterile, and contain antimicrobial activity, so it must be evaluated using laboratory testing. The aim of this descriptive laboratory study was to isolate and identify the bacterial contaminant in the traditional-packed honey dealing with the use of honey for medical purposes. the colony forming units of honey sample cultured on blood agar were counted using Stuart bacterial colony counter. The suspected bacterial colonies were isolated and identified based on cultural morphology characteristics. The isolates of suspected bacterial colonies were stained according to Gram and Klein method and then were examined by the biochemical reaction. The results showed that there were two contaminant bacteria. Gram-positive cocci which were presumptively identified as coagulase-negative Staphylococci and gram-positive rods which were presumptively identified as Bacillus subtilis. In conclusion, the contaminant bacteria were regarded as low pathogen bacteria. The subtilin enzyme of B subtilis may cause an allergic reaction and coagulase-negative Staphylococci, Staphylococcus epidermidis is also an opportunist pathogen. Inevitably, for medical purposes, traditional-packed honey must be well filtered, water content above 18%, and standardized sterilization without loss of an antibacterial activity or change in properties.

  20. Excitons in intact cells of photosynthetic bacteria.

    Science.gov (United States)

    Freiberg, Arvi; Pajusalu, Mihkel; Rätsep, Margus

    2013-09-26

    Live cells and regular crystals seem fundamentally incompatible. Still, effects characteristic to ideal crystals, such as coherent sharing of excitation, have been recently used in many studies to explain the behavior of several photosynthetic complexes, especially the inner workings of the light-harvesting apparatus of the oldest known photosynthetic organisms, the purple bacteria. To this date, there has been no concrete evidence that the same effects are instrumental in real living cells, leaving a possibility that this is an artifact of unnatural study conditions, not a real effect relevant to the biological operation of bacteria. Hereby, we demonstrate survival of collective coherent excitations (excitons) in intact cells of photosynthetic purple bacteria. This is done by using excitation anisotropy spectroscopy for tracking the temperature-dependent evolution of exciton bands in light-harvesting systems of increasing structural complexity. The temperature was gradually raised from 4.5 K to ambient temperature, and the complexity of the systems ranged from detergent-isolated complexes to complete bacterial cells. The results provide conclusive evidence that excitons are indeed one of the key elements contributing to the energetic and dynamic properties of photosynthetic organisms.

  1. Functionalized carbon nanotubes in ZnO thin films for photoinactivation of bacteria

    International Nuclear Information System (INIS)

    Akhavan, O.; Azimirad, R.; Safa, S.

    2011-01-01

    Highlights: → Unfunctionalized and functionalized MWCNT/ZnO thin films were synthesized by sol-gel method. → Zn-O-C carbonaceous bonds formed in the functionalized MWCNT/ZnO thin films. → The functionalized MWCNT/ZnO had stronger photoinactivation of the bacteria than the unfunctionalize type. → 10 wt% functionalized MWCNT content had the optimum antibacterial property. - Abstract: Two types of unfunctionalized and functionalized multi-wall carbon nanotubes (MWCNTs) were prepared to be applied in fabrication of MWCNT-ZnO nanocomposite thin films with various MWCNT contents. X-ray photoelectron spectroscopy indicated formation of functional groups on surface of the functionalized MWCNTs in the MWCNT-ZnO nanocomposite. Formation of the effective carbonaceous bonds between the ZnO and the MWCNTs was also investigated through photoinactivation of Escherichia coli bacteria on surface of the both unfunctionalized and functionalized MWCNT-ZnO nanocomposites. The functionalized MWCNT-ZnO nanocomposites showed significantly stronger photoinactivation of the bacteria than the unfunctionalized ones, for all of the various MWCNT contents (from 2 to 30 wt%). While the functionalized MWCNT-ZnO nanocomposites with the optimum MWCNT content of 10 wt% inactivated whole of the bacteria after 10 min UV-visible light irradiation, the unfunctionalized ones could inactivate only 63% of the bacteria under the same conditions. The significant enhancement of the photoinactivation of the bacteria onto the surface of the functionalized MWCNT-ZnO nanocomposites was assigned to charge transfer through Zn-O-C bands formed between the Zn atoms of the ZnO film and oxygen atoms of the carboxylic functional groups of the functionalized MWCNTs.

  2. NREL Scientists Model Methane-Eating Bacteria | News | NREL

    Science.gov (United States)

    Scientists Model Methane-Eating Bacteria News Release: NREL Scientists Model Methane-Eating Bacteria February 13, 2018 Nature is full of surprises - not to mention solutions. A research team ) recently explored the possibilities provided by the natural world by researching how the bacteria

  3. Quantification and Qualification of Bacteria Trapped in Chewed Gum

    NARCIS (Netherlands)

    Wessel, Stefan W.; van der Mei, Henny C.; Morando, David; Slomp, Anje M.; van de Belt-Gritter, Betsy; Maitra, Amarnath; Busscher, Henk J.

    2015-01-01

    Chewing of gum contributes to the maintenance of oral health. Many oral diseases, including caries and periodontal disease, are caused by bacteria. However, it is unknown whether chewing of gum can remove bacteria from the oral cavity. Here, we hypothesize that chewing of gum can trap bacteria and

  4. Isolation and characterization of feather degrading bacteria from ...

    African Journals Online (AJOL)

    This study is aimed at isolating and characterizing new culturable feather degrading bacteria from soils of the University of Mauritius Farm. Bacteria that were isolated were tested for their capability to grow on feather meal agar (FMA). Proteolytic bacteria were tested for feather degradation and were further identified ...

  5. Bacteria associated with cultures of psathyrella atroumbonata (Pleger)

    African Journals Online (AJOL)

    These bacteria include Bacillus licheniformis, Bacillus subtilis, Leuconostoc mesenteroides, Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus. The average bacteria count was 1.0 x 106 cfu/ml and these bacteria grew within pH range of 5.0 and 9.0. the optimum temperature range of growth lied ...

  6. The growth of bacteria on organic compounds in drinking water

    NARCIS (Netherlands)

    Kooij, van der D.

    1984-01-01

    Growth ("regrowth") of bacteria In drinking water distribution systems results in a deterioration of the water quality. Regrowth of chemoheterotrophic bacteria depends on the presence of organic. compounds that serve as a nutrient source for these bacteria. A batch-culture technique was

  7. Bacteria associated with contamination of ready-to-eat (RTE ...

    African Journals Online (AJOL)

    The bacteria associated with contamination of ready-to-eat (RTE) cooked rice in Lagos, Nigeria were studied using standard microbiological methods. The objective of this study was to investigate the distribution of pathogenic bacteria recovered from RTE cooked rice in Lagos, assess bacteria load in the contaminated RTE ...

  8. Patterns and sources of fecal coliform bacteria in three streams in Virginia, 1999-2000

    Science.gov (United States)

    Hyer, Kenneth; Moyer, Douglas

    2003-01-01

    Surface-water impairment by fecal coliform bacteria is a water-quality issue of national scope and importance. In Virginia, more than 175 stream segments are on the Commonwealth's 1998 303(d) list of impaired waters because of elevated concentrations of fecal coliform bacteria. These fecal coliform-impaired stream segments require the development of total maximum daily load (TMDL) and associated implementation plans, but accurate information on the sources contributing these bacteria usually is lacking. The development of defendable fecal coliform TMDLs and management plans can benefit from reliable information on the bacteria sources that are responsible for the impairment. Bacterial source tracking (BST) recently has emerged as a powerful tool for identifying the sources of fecal coliform bacteria that impair surface waters. In a demonstration of BST technology, three watersheds on Virginia's 1998 303(d) list with diverse land-use practices (and potentially diverse bacteria sources) were studied. Accotink Creek is dominated by urban land uses, Christians Creek by agricultural land uses, and Blacks Run is affected by both urban and agricultural land uses. During the 20-month field study (March 1999?October 2000), water samples were collected from each stream during a range of flow conditions and seasons. For each sample, specific conductance, dissolved oxygen concentration, pH, turbidity, flow, and water temperature were measured. Fecal coliform concentrations of each water sample were determined using the membrane filtration technique. Next, Escherichia coli (E. coli) were isolated from the fecal coliform bacteria and their sources were identified using ribotyping (a method of 'genetic fingerprinting'). Study results provide enhanced understanding of the concentrations and sources of fecal coliform bacteria in these three watersheds. Continuum sampling (sampling along the length of the streams) indicated that elevated concentrations of fecal coliform bacteria

  9. Bacteria-Targeting Nanoparticles for Managing Infections

    Science.gov (United States)

    Radovic-Moreno, Aleksandar Filip

    Bacterial infections continue to be a significant concern particularly in healthcare settings and in the developing world. Current challenges include the increasing spread of drug resistant (DR) organisms, the side effects of antibiotic therapy, the negative consequences of clearing the commensal bacterial flora, and difficulties in developing prophylactic vaccines. This thesis was an investigation of the potential of a class of polymeric nanoparticles (NP) to contribute to the management of bacterial infections. More specifically, steps were taken towards using these NPs (1) to achieve greater spatiotemporal control over drug therapy by more targeted antibiotic delivery to bacteria, and (2) to develop a prophylactic vaccine formulation against the common bacterial sexually transmitted disease (STD) caused by Chlamydia trachomatis. In the first part, we synthesized polymeric NPs containing poly(lactic-co-glycolic acid)-block-poly(L-histidine)-block-poly(ethylene glycol) (PLGA-PLH-PEG). We show that these NPs are able to bind to bacteria under model acidic infection conditions and are able to encapsulate and deliver vancomycin to inhibit the growth of Staphylococcus aureus bacteria in vitro. Further work showed that the PLGA-PLH-PEG-based NPs demonstrated the potential for competition for binding bacteria at a site of infection from soluble protein and model phagocytic and tissue-resident cells in a NP composition dependent manner. The NPs demonstrated low toxicity in vitro, were well tolerated by mice in vivo, and circulated in the blood on timescales comparable to control PLGA-PEG NPs. In the second part, we used PLGA-PLH-PEG-based NPs to design a prophylactic vaccine against the obligate intracellular bacterium Chlamydia trachomatis, the most common cause of bacterial STD in the world. Currently, no vaccines against this pathogen are approved for use in humans. We first formulated NPs encapsulating the TLR7 agonist R848 conjugated to poly(lactic acid) (R848-PLA

  10. Isolation and Presumptive Identification of Adherent Epithelial Bacteria (“Epimural” Bacteria) from the Ovine Rumen Wall

    OpenAIRE

    Mead, Lorna J.; Jones, G. A.

    1981-01-01

    One hundred sixty-one strains of adherent bacteria were isolated under anaerobic conditions from four sites on the rumen epithelial surface of sheep fed hay or a hay-grain ration. Before isolation of bacteria, rumen tissue was washed six times in an anaerobic dilution solution, and viable bacteria suspended in the washings were counted. Calculation indicated that unattached bacteria would have been removed from the tissue by this procedure, but a slow and progressive release of attached bacte...

  11. Intercellular wiring enables electron transfer between methanotrophic archaea and bacteria.

    Science.gov (United States)

    Wegener, Gunter; Krukenberg, Viola; Riedel, Dietmar; Tegetmeyer, Halina E; Boetius, Antje

    2015-10-22

    The anaerobic oxidation of methane (AOM) with sulfate controls the emission of the greenhouse gas methane from the ocean floor. In marine sediments, AOM is performed by dual-species consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB) inhabiting the methane-sulfate transition zone. The biochemical pathways and biological adaptations enabling this globally relevant process are not fully understood. Here we study the syntrophic interaction in thermophilic AOM (TAOM) between ANME-1 archaea and their consortium partner SRB HotSeep-1 (ref. 6) at 60 °C to test the hypothesis of a direct interspecies exchange of electrons. The activity of TAOM consortia was compared to the first ANME-free culture of an AOM partner bacterium that grows using hydrogen as the sole electron donor. The thermophilic ANME-1 do not produce sufficient hydrogen to sustain the observed growth of the HotSeep-1 partner. Enhancing the growth of the HotSeep-1 partner by hydrogen addition represses methane oxidation and the metabolic activity of ANME-1. Further supporting the hypothesis of direct electron transfer between the partners, we observe that under TAOM conditions, both ANME and the HotSeep-1 bacteria overexpress genes for extracellular cytochrome production and form cell-to-cell connections that resemble the nanowire structures responsible for interspecies electron transfer between syntrophic consortia of Geobacter. HotSeep-1 highly expresses genes for pili production only during consortial growth using methane, and the nanowire-like structures are absent in HotSeep-1 cells isolated with hydrogen. These observations suggest that direct electron transfer is a principal mechanism in TAOM, which may also explain the enigmatic functioning and specificity of other methanotrophic ANME-SRB consortia.

  12. Screening and characterization of phosphate solubilizing bacteria from isolate of thermophilic bacteria

    Science.gov (United States)

    Yulianti, Evy; Rakhmawati, Anna

    2017-08-01

    The aims of this study were to select bacteria that has the ability to dissolve phosphate from thermophilic bacteria isolates after the Merapi eruption. Five isolates of selected bacteria was characterized and continued with identification. Selection was done by using a pikovskaya selective medium. Bacterial isolates were grown in selective medium and incubated for 48 hours at temperature of 55 ° C. Characterization was done by looking at the cell and colony morphology, physiological and biochemical properties. Identification was done with the Profile Matching method based on the reference genus Oscillospira traced through Bergey's Manual of Determinative Bacteriology. Dendogram was created based on similarity index SSM. The results showed there were 14 isolates of bacteria that were able to dissolve phosphate indicated by a clear zone surrounding the bacterial colony on selective media. Five isolates were selected with the largest clear zone. Isolates D79, D92, D110a, D135 and D75 have different characters. The result of phenotypic characters identification with Genus Oscillospira profile has a percentage of 100% similarity to isolate D92 and D110a; 92.31% for isolates D79, and 84.6% for isolates D75 and D135. Dendogram generated from average linkage algorithm / UPGMA using the Simple Matching Coefficient (SSM) algorithms showed, isolate thermophilic bacteria D75 and D135 are combined together to form cluster 1. D110a and D92 form a sub cluster A. Sub cluster A and D79 form cluster 2

  13. Rationalizing and advancing the 3-MPBA SERS sandwich assay for rapid detection of bacteria in environmental and food matrices.

    Science.gov (United States)

    Pearson, Brooke; Mills, Alexander; Tucker, Madeline; Gao, Siyue; McLandsborough, Lynne; He, Lili

    2018-06-01

    Bacterial foodborne illness continues to be a pressing issue in our food supply. Rapid detection methods are needed for perishable foods due to their short shelf lives and significant contribution to foodborne illness. Previously, a sensitive and reliable surface-enhanced Raman spectroscopy (SERS) sandwich assay based on 3-mercaptophenylboronic acid (3-MBPA) as a capturer and indicator molecule was developed for rapid bacteria detection. In this study, we explored the advantages and constraints of this assay over the conventional aerobic plate count (APC) method and further developed methods for detection in real environmental and food matrices. The SERS sandwich assay was able to detect environmental bacteria in pond water and on spinach leaves at higher levels than the APC method. In addition, the SERS assay appeared to have higher sensitivity to quantify bacteria in the stationary phase. On the other hand, the APC method was more sensitive to cell viability. Finally, a method to detect bacteria in a challenging high-sugar juice matrix was developed to enhance bacteria capture. This study advanced the SERS technique for real applications in environment and food matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Biocatalyst Enhancement

    Science.gov (United States)

    The increasing availability of enzyme collections has assisted attempts by pharmaceutical producers to adopt green chemistry approaches to manufacturing. A joint effort between an enzyme producer and a pharmaceutical manufacturer has been enhanced over the past three years by ena...

  15. Endophytic Bacteria Associated with Hieracium piloselloides: Their Potential for Hydrocarbon-Utilizing and Plant Growth-Promotion.

    Science.gov (United States)

    Pawlik, Małgorzata; Piotrowska-Seget, Zofia

    2015-01-01

    The aim of this study was to assess the potential of 18 crude-oil-degrading endophytic bacteria for removal of hydrocarbons and promotion of plant growth. Strains were isolated from Hieracium piloselloides (tall hawkweed), which grows in soil heavily polluted with petroleum hydrocarbons. Bacteria from the genus Pseudomonas were abundant among the isolates. The potential for hydrocarbon degradation was evaluated by polymerase chain reaction (PCR) analyses of the genes alkB, alkH, C23O, P450, and pah. It was found that 88.89% of the endophytic bacteria contained gene-encoding polycyclic aromatic hydrocarbon (PAH) initial dioxygenase, 61% possessed the 2,3-catechol dioxygenase gene, and 39% of strains that were tested had the cytochrome P-450 hydroxylase gene. All isolates were capable of producing indole-3-acetic acid (1.8-76.4 μg/ml). Only 17% of them were able to produce siderophores, excrete cellulase, and solubilize phosphate. Hydrogen cyanide synthesis occurred in 33% of endophytic bacteria. The 1-aminocyclopropane-1-carboxylate deaminase activity in isolates that were screened was in the range of 2.6 to 74.1 μmol α-ketobutyrate/mg/h. This feature of the bacteria indicated that isolates may enhance the phytoremediation process. Data suggest that crude-oil-degrading endophytic bacteria possess potential to be promising candidates for enhancement of phytoremediation of hydrocarbon-contaminated soil. Further evaluation of these bacteria is needed in order to assess the role played in the degradation of petroleum hydrocarbons.

  16. Screening and biological characteristics of fufenozide degrading bacteria

    Science.gov (United States)

    Xu, Chenhao; Gong, Mingfu; Guan, Qinlan; Deng, Xia; Deng, Hongyan; Huang, Jiao

    2018-04-01

    Fufenozide was a novel pesticide for the control of Lepidoptera pests, which was highly toxic to silkworm. Fufenozide-contaminated soil samples were collected and the bacteria that degrade fufenozide were isolated and screened by selective medium. The colony characteristics, cell characteristics and degradation characteristics in different concentrations fufenozide of the fufenozide degrading bacteria were studied. The results indicated that seven strains of fufenozide degradeing bacteria, named as DDH01, DDH03, DDH04, DDH04, DDH05, DDH07 and DDH07 respectively, were isolated from soil contaminated with fufenozide. DDH01, DDH02, DDH04 and DDH05 of seven fufenozide degrading bacteria, was gram-positive bacteria, and DDH03, DDH06 and DDH07 was gram-negative bacteria. All of seven strains of fufenozide degrading bacteria were not spores, weeks flagella, rod-shaped bacteria. DDH06 and DDH07 had capsules, and the remaining five strains had not capsule. The colonies formed by seven strains of fufenozide degradation bacteria on beef extract peptone medium plate were milky white colonies with irregular edges, thinner lawn, smaller colony with smooth surface. The growth of 7 strains of fufenozide degradation bacteria was significantly affected by the concentration of fufenozide, All of 7 strains grown in the range from 0.00025 g/mL to 1 g/mL of 10% fufenozide suspension. DDH2 was the best among the 7 strains of fufenozide degrading bacteria grown in 10% fufenozide suspension medium.

  17. Influence of bacteria on Pb and Zn speciation, mobility and bioavailability in soil: A laboratory study

    International Nuclear Information System (INIS)

    Wu, S.C.; Luo, Y.M.; Cheung, K.C.; Wong, M.H.

    2006-01-01

    A soil column experiment was carried out to investigate the effects of inoculation of bacteria on metal bioavailability, mobility and potential leachability through single chemical extraction, consequential extraction and in situ soil solution extraction technologies. Results showed that bacteria inoculated, including Azotobacter chroococcum, Bacillus megaterium and Bacillus mucilaginosus, may pose both positive and negative impacts on bioavailability and mobility of heavy metals in soil, depending on the chemical nature of the metals. The activities of bacteria led to an increase of water dissolved organic carbon (DOC) concentration and a decrease of pH value, which enhanced metal mobility and bioavailability (e.g. an increase of water-soluble and HOAc-soluble Zn). On the other hand, bacteria could immobilize metals (e.g. a great reduction of water-soluble Pb) due to the adsorption by bacterial cell walls and possible sedimentation reactions with phosphate or other anions produced through bacterial metabolism. - Influence of bacterial activities on heavy metal is two-edged

  18. Batch experiment on H2S degradation by bacteria immobilised on activated carbons.

    Science.gov (United States)

    Yan, R; Ng, Y L; Chen, X G; Geng, A L; Gould, W D; Duan, H Q; Liang, D T; Koe, L C C

    2004-01-01

    Biological treatments of odorous compounds, as compared to chemical or physical technologies, are in general ecologically and environmentally favourable. However, there are some inefficiencies relative to the media used in biofiltration processes, such as the need for an adequate residence time; the limited lifetime, and pore blockage of media, which at present render the technology economically non-viable. The aim of the study is to develop novel active media to be used in performance-enhanced biofiltration processes, by achieving an optimum balance and combination of the media adsorption capacity with the biodegradation of H2S through the bacteria immobilised on the media. An enrichment culture was obtained from activated sludges in order to metabolise thiosulphate. Batch-wise experiments were conducted to optimise the bacteria immobilisation on activated carbon, so as to develop a novel "biocarbon". Biofilm was mostly developed through culturing the bacteria with the presence of carbons in mineral media. SEM and BET tests of the carbon along with the culturing process were used to identify, respectively, the biofilm development and biocarbon porosity. Breakthrough tests evaluated the biocarbon performance with varying gas resistance time, inlet H2S concentration, and type of support materials. Fundamental issues were discussed, including type of support material, mode of bacteria immobilisation, pore blockages, and biodegradation kinetics, etc. This batch-wise study provides a basis for our future research on optimisation of the biofiltration process using a bio-trickling reactor.

  19. Differential oxidative and antioxidative response of duckweed Lemna minor toward plant growth promoting/inhibiting bacteria.

    Science.gov (United States)

    Ishizawa, Hidehiro; Kuroda, Masashi; Morikawa, Masaaki; Ike, Michihiko

    2017-09-01

    Bacteria colonizing the plant rhizosphere are believed to positively or negatively affect the host plant productivity. This feature has inspired researchers to engineer such interactions to enhance crop production. However, it remains to be elucidated whether rhizobacteria influences plant oxidative stress vis-a-vis other environmental stressors, and whether such influence is associated with their growth promoting/inhibiting ability. In this study, two plant growth-promoting bacteria (PGPB) and two plant growth-inhibiting bacteria (PGIB) were separately inoculated into axenic duckweed (Lemna minor) culture under laboratory conditions for 4 and 8 days in order to investigate their effects on plant oxidative stress and antioxidant activities. As previously characterized, the inoculation of PGPB and PGIB strains accelerated and reduced the growth of L. minor, respectively. After 4 and 8 days of cultivation, compared to the PGPB strains, the PGIB strains induced larger amounts of O 2 •- , H 2 O 2 , and malondialdehyde (MDA) in duckweed, although all bacterial strains consistently increased O 2 •- content by two times more than that in the aseptic control plants. Activities of five antioxidant enzymes were also elevated by the inoculation of PGIB, confirming the severe oxidative stress condition in plants. These results suggest that the surface attached bacteria affect differently on host oxidative stress and its response, which degree correlates negatively to their effects on plant growth. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Activation of type III interferon genes by pathogenic bacteria in infected epithelial cells and mouse placenta.

    Directory of Open Access Journals (Sweden)

    Hélène Bierne

    Full Text Available Bacterial infections trigger the expression of type I and II interferon genes but little is known about their effect on type III interferon (IFN-λ genes, whose products play important roles in epithelial innate immunity against viruses. Here, we studied the expression of IFN-λ genes in cultured human epithelial cells infected with different pathogenic bacteria and in the mouse placenta infected with Listeria monocytogenes. We first showed that in intestinal LoVo cells, induction of IFN-λ genes by L. monocytogenes required bacterial entry and increased further during the bacterial intracellular phase of infection. Other Gram-positive bacteria, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis, also induced IFN-λ genes when internalized by LoVo cells. In contrast, Gram-negative bacteria Salmonella enterica serovar Typhimurium, Shigella flexneri and Chlamydia trachomatis did not substantially induce IFN-λ. We also found that IFN-λ genes were up-regulated in A549 lung epithelial cells infected with Mycobacterium tuberculosis and in HepG2 hepatocytes and BeWo trophoblastic cells infected with L. monocytogenes. In a humanized mouse line permissive to fetoplacental listeriosis, IFN-λ2/λ3 mRNA levels were enhanced in placentas infected with L. monocytogenes. In addition, the feto-placental tissue was responsive to IFN-λ2. Together, these results suggest that IFN-λ may be an important modulator of the immune response to Gram-positive intracellular bacteria in epithelial tissues.

  1. Diversity and natural functions of antibiotics produced by beneficial and plant pathogenic bacteria.

    Science.gov (United States)

    Raaijmakers, Jos M; Mazzola, Mark

    2012-01-01

    Soil- and plant-associated environments harbor numerous bacteria that produce antibiotic metabolites with specific or broad-spectrum activities against coexisting microorganisms. The function and ecological importance of antibiotics have long been assumed to yield a survival advantage to the producing bacteria in the highly competitive but resource-limited soil environments through direct suppression. Although specific antibiotics may enhance producer persistence when challenged by competitors or predators in soil habitats, at subinhibitory concentrations antibiotics exhibit a diversity of other roles in the life history of the producing bacteria. Many processes modulated by antibiotics may be inherently critical to the producing bacterium, such as the acquisition of substrates or initiation of developmental changes that will ensure survival under stressful conditions. Antibiotics may also have roles in more complex interactions, including in virulence on host plants or in shaping the outcomes of multitrophic interactions. The innate functions of antibiotics to producing bacteria in their native ecosystem are just beginning to emerge, but current knowledge already reveals a breadth of activities well beyond the historical perspective of antibiotics as weaponry in microbial conflicts.

  2. Quantitative assay for the colonization ability of heterogeneous bacteria on controlled nanopillar structures

    International Nuclear Information System (INIS)

    Jin, Lin; Guo, Wen; Zhang, Yali; Xue, Peihong; Gao, Hainan; Zhao, Ming; Zheng, Chen; Han, Dong

    2015-01-01

    The colonization ability of bacteria on biomaterial surfaces is influenced by the morphology of the bacteria and the nanotopography of the biomaterial. However, interactions between the bacterial morphology and nanotopography of biomaterials have not yet been completely elucidated. In this article, we quantitatively characterized the bacterial morphology to illuminate the integrated effects of polyethylene terephthalate (PET) nanopillar arrays on the colonization of bacteria cells with different shapes. Our results demonstrated that the interaction between interpillar spacing and the diameter of the bacterial cells impacted the number of bacterial cells that adhered to different PET substrates. The interpillar spacing of nanopillar arrays promotes bacterial adhesion in a definite range (<50 nm). However, further increasing the interpillar spacing inhibited the adhesion of bacteria to the nanopillar arrays. Moreover, the interpillar spacing also influenced the morphologies of adherent bacterial cells on the PET nanopillar arrays, which consequently facilitated bacterial adhesion to the nanopillar arrays. Our findings enhance the understanding of interactions between controlled nanotopography and bacterial colonization and provide an appropriate parameter for the design of antibacterial materials with nanotopography. (paper)

  3. The role of intestinal microflora and probiotic bacteria in prophylactic and development of colorectal cancer

    Directory of Open Access Journals (Sweden)

    Ewa Wasilewska

    2013-08-01

    Full Text Available The gut microbiota comprises a large and diverse range of microorganisms whose activities have a significant impact on health. It interacts with its host at both the local and systemic level, resulting in a broad range of beneficial or detrimental outcomes for nutrition, infections, xenobiotic metabolism, and cancer. The current paper reviews research on the role of intestinal microflora in colorectal cancer development. Especially a protective effect of beneficial bacteria and probiotics on the risk of cancer development is highly discussed. There is substantial experimental evidence that the beneficial gut bacteria and their metabolism have the potential to inhibit the development and progression of neoplasia in the large intestine. Most of the data derive, however, from experimental and animal trials. Over a dozen well-documented animal studies have been published, wherein it has been clearly revealed that some lactic acid bacteria, especially lactobacilli and bifidobacteria, inhibit initiation and progression of colorectal cancer. Studies on cancer suppression in humans as a result of the consumption of probiotics are still sparse. Nevertheless, some epidemiological and interventional studies seem to confirm the bacterial anticancerogenic activity also in human gut. The mechanism by which probiotics may inhibit cancer development is unknown. Probiotics increase the amount of beneficial bacteria and decrease the pathogen level in the gut, consequently altering metabolic, enzymatic and carcinogenic activity in the intestine, decreasing inflammation and enhancing immune function, which may contribute to cancer defense.

  4. Probiotic bacteria: selective enumeration and survival in dairy foods.

    Science.gov (United States)

    Shah, N P

    2000-04-01

    A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp., and Lactobacillus casei. Because of the potential health benefits, these organisms are increasingly incorporated into dairy foods. However, studies have shown low viability of probiotics in market preparations. In order to assess viability of probiotic bacteria, it is important to have a working method for selective enumeration of these probiotic bacteria. Viability of probiotic bacteria is important in order to provide health benefits. Viability of probiotic bacteria can be improved by appropriate selection of acid and bile resistant strains, use of oxygen impermeable containers, two-step fermentation, micro-encapsulation, stress adaptation, incorporation of micronutrients such as peptides and amino acids and by sonication of yogurt bacteria. This review will cover selective enumeration and survival of probiotic bacteria in dairy foods.

  5. The influence of protruding filamentous bacteria on floc stability and solid-liquid separation in the activated sludge process.

    Science.gov (United States)

    Burger, Wilhelm; Krysiak-Baltyn, Konrad; Scales, Peter J; Martin, Gregory J O; Stickland, Anthony D; Gras, Sally L

    2017-10-15

    Filamentous bacteria can impact on the physical properties of flocs in the activated sludge process assisting solid-liquid separation or inducing problems when bacteria are overabundant. While filamentous bacteria within the flocs are understood to increase floc tensile strength, the relationship between protruding external filaments, dewatering characteristics and floc stability is unclear. Here, a quantitative methodology was applied to determine the abundance of filamentous bacteria in activated sludge samples from four wastewater treatment plants. An automated image analysis procedure was applied to identify filaments and flocs and calculate the length of the protruding filamentous bacteria (PFB) relative to the floc size. The correlation between PFB and floc behavior was then assessed. Increased filament abundance was found to increase interphase drag on the settling flocs, as quantified by the hindered settling function. Additionally, increased filament abundance was correlated with a lower gel point concentration leading to poorer sludge compactability. The floc strength factor, defined as the relative change in floc size upon shearing, correlated positively with filament abundance. This influence of external protruding filamentous bacteria on floc stability is consistent with the filamentous backbone theory, where filamentous bacteria within flocs increase floc resistance to shear-induced breakup. A qualitative correlation was also observed between protruding and internal filamentous structure. This study confirms that filamentous bacteria are necessary to enhance floc stability but if excessively abundant will adversely affect solid-liquid separation. The tools developed here will allow quantitative analysis of filament abundance, which is an improvement on current qualitative methods and the improved method could be used to assist and optimize the operation of waste water treatment plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Introduce of Viable But Nonculturable Bacteria

    Directory of Open Access Journals (Sweden)

    Mehdi Hassanshahian

    2008-03-01

    Full Text Available Viable-But-Nonculturable-State (VBNC is the condition in which bacteria fail to grow on their routine bacteriological media where they would normally grow and develop into colonies, but are still alive and capable of renewed metabolic activity. VBNC state is useful for evaluating public health and for ascertaining the sterility of drinking water, pharmaceuticals, and foodstuff. A number of bacteria, mostly pathogenic to humans, have been proved to enter into this state in response to natural stresses such as starvation, incubation out of optimum growth temperature, increased osmotic pressure, etc. Once in the VBNC state, they undergo various physiological, structural, and genetic alterations. These alterations result in reduced cell size, conversion from bacilli to coccid, thickened cell walls, and peptidoglycan gaining many cross links. Metabolic changes also occur that include reductions in growth, nutrient transport, and respiratory rate; biosynthesis of new protein, and ATP remaining at a constant level. It has been shown that in the VBNC state, some pathogens conserve their virulence properties. Gene expression continues in the VBNC cell. Nucleic acids remain intact in the early VBNC phase but they gradually undergo degradation with prolonged VBNC. Cytological methods such as direct viable count and reduction of tetrazolium salts, and molecular methods such as reverse transcription polymerase chain reaction and green fluorescent protein have been used for the study of VBNC. Resuscitation from VBNC state starts when the inducing factor(s is/are lifted. Factors that help the resuscitation of VBNC bacteria include addition of certain nutrients and chemicals, introduction of a few culturable cells into the VBNC cell population, and passage through the animal host. As virulence properties are sustained during the VBNC phase, special care must be paid when evaluating sterility of drinking water.

  7. Catecholate siderophores protect bacteria from pyochelin toxicity.

    Directory of Open Access Journals (Sweden)

    Conrado Adler

    Full Text Available Bacteria produce small molecule iron chelators, known as siderophores, to facilitate the acquisition of iron from the environment. The synthesis of more than one siderophore and the production of multiple siderophore uptake systems by a single bacterial species are common place. The selective advantages conferred by the multiplicity of siderophore synthesis remains poorly understood. However, there is growing evidence suggesting that siderophores may have other physiological roles besides their involvement in iron acquisition.Here we provide the first report that pyochelin displays antibiotic activity against some bacterial strains. Observation of differential sensitivity to pyochelin against a panel of bacteria provided the first indications that catecholate siderophores, produced by some bacteria, may have roles other than iron acquisition. A pattern emerged where only those strains able to make catecholate-type siderophores were resistant to pyochelin. We were able to associate pyochelin resistance to catecholate production by showing that pyochelin-resistant Escherichia coli became sensitive when biosynthesis of its catecholate siderophore enterobactin was impaired. As expected, supplementation with enterobactin conferred pyochelin resistance to the entE mutant. We observed that pyochelin-induced growth inhibition was independent of iron availability and was prevented by addition of the reducing agent ascorbic acid or by anaerobic incubation. Addition of pyochelin to E. coli increased the levels of reactive oxygen species (ROS while addition of ascorbic acid or enterobactin reduced them. In contrast, addition of the carboxylate-type siderophore, citrate, did not prevent pyochelin-induced ROS increases and their associated toxicity.We have shown that the catecholate siderophore enterobactin protects E. coli against the toxic effects of pyochelin by reducing ROS. Thus, it appears that catecholate siderophores can behave as protectors of

  8. Repair by genetic recombination in bacteria: overview

    International Nuclear Information System (INIS)

    Howard-Flanders, P.

    1975-01-01

    DNA molecules that have been damaged in both strands at the same level are not subject to repair by excision but instead can be repaired through recombination with homologous molecules. Examples of two-strand damage include postreplication gaps opposite pyrimidine dimers, two-strand breaks produced by x-rays, and chemically induced interstrand cross-links. In ultraviolet-irradiated bacteria, and newly synthesized DNA is of length equal to the interdimer spacing. With continued incubation, this low-molecular-weight DNA is joined into high-molecular-weight chains (postreplication repair), a process associated with sister exchanges in bacteria. Recombination is initiated by pyrimidine dimers opposite postreplication gaps and by interstrand cross-links that have been cut by excision enzymes. The free ends at the resulting gaps presumably initiate the exchanges. Postreplication repair in Escherichia coli occurs in recB - and recC - but is greatly slowed in recF - mutants. RecB and recC are the structural genes for exonuclease V, which digests two-stranded DNA by releasing oligonucleotides first from one strand and then from the other. The postreplication sister exchanges in ultraviolet-irradiated bacteria result in the distribution of pyrimidine dimers between parental and daughter strands, indicating that long exchanges involving both strands of each duplex occur. The R1 restriction endonuclease from E. coli has been used to cut the DNA of a bacterial drug-resistance transfer factor with one nuclease-sensitive site, and also DNA from the frog Xenopus enriched for ribosomal 18S and 28S genes. The fragments were annealed with the cut plasmid DNA and ligated, producing a new larger plasmid carrying the eukaryotic rDNA and able to infect and replicate in E. coli

  9. Close Encounters of Lymphoid Cells and Bacteria

    Science.gov (United States)

    Cruz-Adalia, Aranzazu; Veiga, Esteban

    2016-01-01

    During infections, the first reaction of the host against microbial pathogens is carried out by innate immune cells, which recognize conserved structures on pathogens, called pathogen-associated molecular patterns. Afterward, some of these innate cells can phagocytose and destroy the pathogens, secreting cytokines that would modulate the immune response to the challenge. This rapid response is normally followed by the adaptive immunity, more specific and essential for a complete pathogen clearance in many cases. Some innate immune cells, usually named antigen-presenting cells, such as macrophages or dendritic cells, are able to process internalized invaders and present their antigens to lymphocytes, triggering the adaptive immune response. Nevertheless, the traditional boundary of separated roles between innate and adaptive immunity has been blurred by several studies, showing that very specialized populations of lymphocytes (cells of the adaptive immunity) behave similarly to cells of the innate immunity. These “innate-like” lymphocytes include γδ T cells, invariant NKT cells, B-1 cells, mucosal-associated invariant T cells, marginal zone B cells, and innate response activator cells, and together with the newly described innate lymphoid cells are able to rapidly respond to bacterial infections. Strikingly, our recent data suggest that conventional CD4+ T cells, the paradigm of cells of the adaptive immunity, also present innate-like behavior, capturing bacteria in a process called transinfection. Transinfected CD4+ T cells digest internalized bacteria like professional phagocytes and secrete large amounts of proinflammatory cytokines, protecting for further bacterial challenges. In the present review, we will focus on the data showing such innate-like behavior of lymphocytes following bacteria encounter. PMID:27774092

  10. Electroactive biofilms of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina; Moura, Jose J.G.

    2008-01-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m -2 that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces

  11. Isolation and biochemical characterizations of the bacteria ...

    African Journals Online (AJOL)

    These isolates yielded off white convex colonies on potato dextrose agar (PDA) media at 29°C with 1.7 to 1.9 mm diameter and were yellow on yeast extract dextrose chalk agar (YDC) media at 27°C with 1.8 to 2.0 mm diameter. The bacteria were rod shape measuring 0.5 to 0.6 × 1.4 to 1.6 μm on PDA and 0.6 to 0.7 × 1.5 to ...

  12. Bioluminescent bacteria: lux genes as environmental biosensors

    Directory of Open Access Journals (Sweden)

    Nunes-Halldorson Vânia da Silva

    2003-01-01

    Full Text Available Bioluminescent bacteria are widespread in natural environments. Over the years, many researchers have been studying the physiology, biochemistry and genetic control of bacterial bioluminescence. These discoveries have revolutionized the area of Environmental Microbiology through the use of luminescent genes as biosensors for environmental studies. This paper will review the chronology of scientific discoveries on bacterial bioluminescence and the current applications of bioluminescence in environmental studies, with special emphasis on the Microtox toxicity bioassay. Also, the general ecological significance of bioluminescence will be addressed.

  13. Polymorphic transformation of helical flagella of bacteria

    Science.gov (United States)

    Lim, Sookkyung; Howard Berg Collaboration; William Ko Collaboration; Yongsam Kim Collaboration; Wanho Lee Collaboration; Charles Peskin Collaboration

    2016-11-01

    Bacteria such as E. coli swim in an aqueous environment by utilizing the rotation of flagellar motors and alternate two modes of motility, runs and tumbles. Runs are steady forward swimming driven by bundles of flagellar filaments whose motors are turning CCW; tumbles involve a reorientation of the direction of swimming triggered by motor reversals. During tumbling, the helical flagellum undergoes polymorphic transformations, which is a local change in helical pitch, helical radius, and handedness. In this work, we investigate the underlying mechanism of structural conformation and how this polymorphic transition plays a role in bacterial swimming. National Science Foundation.

  14. Ethylene-producing bacteria that ripen fruit.

    Science.gov (United States)

    Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

    2014-12-19

    Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples.

  15. Are Bacteria more dangerous in space?

    International Nuclear Information System (INIS)

    Leys, N.; Baatout, S.

    2010-01-01

    With a mission to Mars and a permanent base on the moon as the ultimate dream, space travel is continually pushing back the frontiers. But long space missions present great challenges for science, for example in the field of microbiology. Together with the European Space Agency (ESA), SCK-CEN is studying the effects of space travel conditions on the behaviour of bacteria. In 2009 the SCK-CEN experts completed four innovative research projects at the cutting edge of microbiology, radiation sciences and space travel.

  16. Electroactive biofilms of sulphate reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Moura, Jose J.G. [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)], E-mail: jose.moura@dq.fct.unl.pt

    2008-12-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m{sup -2} that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces.

  17. Bacteria-Triggered Release of Antimicrobial Agents

    DEFF Research Database (Denmark)

    Komnatnyy, Vitaly V.; Chiang, Wen-Chi; Tolker-Nielsen, Tim

    2014-01-01

    Medical devices employed in healthcare practice are often susceptible to microbial contamination. Pathogenic bacteria may attach themselves to device surfaces of catheters or implants by formation of chemically complex biofilms, which may be the direct cause of device failure. Extracellular...... bacterial lipases are particularly abundant at sites of infection. Herein it is shown how active or proactive compounds attached to polymeric surfaces using lipase‐sensitive linkages, such as fatty acid esters or anhydrides, may be released in response to infection. Proof‐of‐concept of the responsive...

  18. Anaerobic bacteria as producers of antibiotics.

    Science.gov (United States)

    Behnken, Swantje; Hertweck, Christian

    2012-10-01

    Anaerobic bacteria are the oldest terrestrial creatures. They occur ubiquitously in soil and in the intestine of higher organisms and play a major role in human health, ecology, and industry. However, until lately no antibiotic or any other secondary metabolite has been known from anaerobes. Mining the genome sequences of Clostridium spp. has revealed a high prevalence of putative biosynthesis genes (PKS and NRPS), and only recently the first antibiotic from the anaerobic world, closthioamide, has been isolated from the cellulose degrading bacterium Clostridium cellulolyticum. The successful genetic induction of antibiotic biosynthesis in an anaerobe encourages further investigations of obligate anaerobes to tap their hidden biosynthetic potential.

  19. A CRISPR-Cas system enhances envelope integrity mediating antibiotic resistance and inflammasome evasion

    NARCIS (Netherlands)

    T.R. Sampson (Timothy); B.A. Napier (Brooke); M.R. Schroeder (Max); J. Zhao (Jingshi); R.P.L. Louwen (Rogier); C.-Y. Chin (Chui-Yoke); H.K. Ratner (Hannah); A.C. Llewellyn (Anna); C.L. Jones (Crystal); H. Laroui (Hamed); D. Merlin (Didier); P. Zhou (Pei); H.P. Endtz (Hubert); D.S. Weiss (David)

    2014-01-01

    textabstractClustered, regularly interspaced, short palindromic repeats-CRISPR associated (CRISPR-Cas) systems defend bacteria against foreign nucleic acids, such as during bacteriophage infection and transformation, processes which cause envelope stress. It is unclear if these machineries enhance

  20. A Glutamic Acid-Producing Lactic Acid Bacteria Isolated from Malaysian Fermented Foods

    Science.gov (United States)

    Zareian, Mohsen; Ebrahimpour, Afshin; Bakar, Fatimah Abu; Mohamed, Abdul Karim Sabo; Forghani, Bita; Ab-Kadir, Mohd Safuan B.; Saari, Nazamid

    2012-01-01

    l-glutamaic acid is the principal excitatory neurotransmitter in the brain and an important intermediate in metabolism. In the present study, lactic acid bacteria (218) were isolated from six different fermented foods as potent sources of glutamic acid producers. The presumptive bacteria were tested for their ability to synthesize glutamic acid. Out of the 35 strains showing this capability, strain MNZ was determined as the highest glutamic-acid producer. Identification tests including 16S rRNA gene sequencing and sugar assimilation ability identified the strain MNZ as Lactobacillus plantarum. The characteristics of this microorganism related to its glutamic acid-producing ability, growth rate, glucose consumption and pH profile were studied. Results revealed that glutamic acid was formed inside the cell and excreted into the extracellular medium. Glutamic acid production was found to be growth-associated and glucose significantly enhanced glutamic acid production (1.032 mmol/L) compared to other carbon sources. A concentration of 0.7% ammonium nitrate as a nitrogen source effectively enhanced glutamic acid production. To the best of our knowledge this is the first report of glutamic acid production by lactic acid bacteria. The results of this study can be further applied for developing functional foods enriched in glutamic acid and subsequently γ-amino butyric acid (GABA) as a bioactive compound. PMID:22754309