Bibliografías temáticas / Environmental bacterial isolates

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Literatura académica sobre el tema "Environmental bacterial isolates"

Autor: Grafiati

Publicado: 11 de marzo de 2023

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Artículos de revistas sobre el tema "Environmental bacterial isolates"

Pattani, Vivek B. "Characterization of Plant Growth-Promoting Activity of Bacteria Isolated from Forest and Coastal Regions of Saurashtra, Gujarat, India". Bioscience Biotechnology Research Communications 15, n.º 1 (25 de marzo de 2022): 144–51. http://dx.doi.org/10.21786/bbrc//15.1.22.

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The haphazard application of chemical fertilizers and pesticides causes tremendous damage to ecosystems and all biota. One of the most effective ways to tackle the threat is to use biofertilizer. Plant growth promoting bacteria (PGPB) are an important bacterial source for microbial fertilizers that can boost agricultural yields by encouraging plant growth. Bacterial isolates isolated from Saurashtra region, Gujarat, India were analysed for their capability to solubilize inorganic 'P' from tri calcium phosphate and production of indole acetic acid (IAA) quantitatively by bacterial. Production of ammonia, siderophore and hydrogen cyanide (HCN) by selected bacteria isolates was analysed. Biochemical characterization of selected bacterial isolates was done using Vitek 2 Compact system. Isolate GFS15C2 showed highest amount of phosphate solubilization, followed by isolate GFS07C1 and GFS01C1. Bacterial isolate GFS15C2 produced highest amount of IAA. All bacterial isolates were able produce ammonia. Eight bacteria isolates were be to produce HCN. Siderophore was produced by 14 bacterial isolates. In biochemical characterization all the bacterial isolates were able to use D-glucose. Based on biochemical characters clustering of bacteria isolates was done using Paleontological statistics software package for education and data analysis(PAST). Using cluster analysis by euclidean distance method based on biochemical characterization isolates GFS16C2 & SCS12C3 was found to have distinct characters than other isolates. The present study attempts to characterize PGPB which could be harnessed to improve plant growth. Several phosphate solubilizers and IAA producers also showed production of siderophores and HCN which suggests that these organisms do possess biocontrol ability. These PGPB microbial inoculants can be utilized to improve agricultural systems or as an alternate means of environmentally friendly plant disease biocontrol.

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Kurniawan, Ardiansyah, Suci Puspita Sari, Euis Asriani, Andi Kurniawan, Abu Bakar Sambah y Asep Awaludin Prihanto. "Molecular Identification of Cellulolytic Bacteria From Mangrove Sediment at Tin Minning Region In West Bangka". International Journal of Applied Biology 3, n.º 1 (29 de junio de 2019): 7. http://dx.doi.org/10.20956/ijab.v3i1.5848.

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Cellulose as an abundant source of glucose in Indonesia requires acceleration of decomposition utilizing cellulolytic bacteria. Cellulolytic bacteria can be obtained from the isolation of mangrove organic matter, such as sediments. Muntok Sub-district is one of the regions with the most tin mining in West Bangka Regency also has mangroves in the coastal area. Exploration of cellulolytic bacteria in mangroves with different environmental characteristics encourages researchers to find new bacterial strains that produce cellulase enzymes with new properties. Thirteen isolates were successfully isolated from three locations. Tembelok mangrove sediments produced Seven bacterial isolates, Peltim Mangrove samples produced three isolates and from Sukal Mangrove three isolates were obtained. Seven isolates showed clear zones in the Lugol test and three isolates including were gram-positive bacteria. Molecular test with 16S rRNA analysis showed TBL1 isolate has 85% similar identity of Vibrio parahaemolyticus strain HY3 and TBL2 isolate has 98% similar identity of Bacillus amyloliquefaciens strain HS8. Bacillus amyloliquefaciens potential to further study as cellulose degrading bacteria for feed ingredients.

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Abid, Suhad A., Sarah Naji Aziz, Noor Al-Huda Ali A. H. Saeed, Shaimaa N. Mizil, Israa M. S. Al-Kadmy, Nadheema H. Hussein, Nadal Al-Saryi, Susan A. Ibrahim y Jumaah D. Hussein. "Investigation of Virulence Factors in Microbial Organisms that Associated with Public Health Risk Isolates from Different Environmental Regions". Al-Mustansiriyah Journal of Science 33, n.º 5 (25 de febrero de 2023): 1–7. http://dx.doi.org/10.23851/mjs.v33i5.1303.

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Infectious diseases caused by infected tools in the environments are threaten to the safety and public health. Transmission sources of these infectious diseases are unknown, but it is thought that non-living materials called fomites, are the major source of acquired infections. Three hundred and one swabs were taken from different sources and cultured on blood agar to study heamolysis ability of isolated bacteria. In this study, MacConkey agar was used to isolate Gram-negative bacteria and Sabouraud agar (SDA) to isolate fungi. The biofilm formation test was done by Congo red plate assay. 41 (13.6%) bacterial isolates were obtained and (18.27%) of fungi were isolated on Sabouraud agar (SDA). Staphylococcus aureus was the more frequent bacterial species that isolated in this study. 29% of samples showed hemolysin activity on blood agar and 32%of the isolates were biofilm- producer. Results revealed that (7.9%) of Gram-negative bacteria harbored the fimH gene, (9%) harbored the icaA were Gram-positive and 6.3 % of fungal samples had HWP1 gene. Furthermore, (9.3%) from the total samples are bacterial samples harbored hla gene belong to Staphylococcus spp. Furthermore, (5.07%) of tested samples possessed hlyA gene were Gram-negative bacteria. We found in our study that infectious organisms can be transmitted from one individual to another by fomites responsible for acquired infection.

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Msango Soko, K. R., R. C. Bhattacharya, B. Ramakrishnan, K. Sharma y S. Subramanian. "Functional characterization of bacteria isolated from different gut compartments of white grub, Anamola dimidiata, larvae". Journal of Environmental Biology 41, n.º 6 (15 de noviembre de 2020): 1526–35. http://dx.doi.org/10.22438/jeb/41/6/mrn-1420.

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Aim: The aim of the present study was to isolate and characterize cellulolytic, lipolytic and nitrate reductase activities in the bacteria isolated from the gut of white grub, Anamola dimidiata larvae Methodology: Field collected third instar scarab larvae were dissected under aseptic conditions and inoculated on different bacteriological media to isolate gut bacteria. Identification of these isolates was carried out by amplifying and sequencing the 16S rRNA gene and comparing with their closest relatives in GenBank. Cellulolytic, lipolytic and nitrate reductase activities were assayed using Carbonmethyl cellulose (CMC), Rhodamine B and nitrate broth media. Results: The majority of culturable bacteria in the gut of A. dimidiata belonged to two phyla: Firmicutes (62.5%) and Proteobacteria (37.5%). Forty aerobic and eleven anaerobic bacterial strains were isolated and tested for cellulolytic, lipolytic and nitrate reductase activity, and twenty seven and thirty one cellulolytic and lipolytic gut bacteria were identified, respectively, with 19 isolates exhibiting both activities whereas ten facultative anaerobic bacteria isolates were positive for nitrate reductase activity. Interpretation: These bacterial isolates may be good sources for profiling novel isolates and enzymes for industrial use besides identifying new solutions for pest control.

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Ropiatningsuari, Nika, Suryo Wiyono y Suryahadi Suryahadi. "Skrining Bakteri Dekomposer Sebagai Penghilang Bau Kotoran Ayam". Bumi Lestari Journal of Environment 18, n.º 1 (1 de febrero de 2018): 19. http://dx.doi.org/10.24843/blje.2018.v18.i01.p03.

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The decomposition of chicken excreta produce odorous gases, that case environmental pollution. One of alternative technique to reduce the odorous gases is by applying specific bacteria. The aim of this study was to obtain bacterial isolates that capable of reducing NH3 and H2S production and odors. Decomposer bacterial candidates were isolated from chicken manure, guano, and peat soil. Selection of isolates of oxidizing bacteria is carried out using selective media. All isolates that were found from chicken manure, guano, and peat soil tested for hypersensitive reaction on tobacco and hemolysis on blood agar. The isolated bacteria that showed negative HR and HL responses than used for a further experiment. Five isolates of bacteria which reduce odors based on organoleptic test were WiK 15, TnK 7, WiGu 11, CGu 7 and MaGa 5. NH3 and H2S from decomposition chicken excreta were analyzed by spectrophotometric and colorimetric method. The average of total NH3 production from seven days observation showed ranged level from 1.09 ppm to 1.77 ppm, while total H2S gas production ranged from 15.05 to 16.57 ppm. Bacterial isolate CGU 7 showed make lowest total production of NH3.

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Khan, M. A., H. Satoh, T. Mino, H. Katayama, F. Kurisu y T. Matsuo. "Bacteriophage-host interaction in the enhanced biological phosphate removing activated sludge system". Water Science and Technology 46, n.º 1-2 (1 de julio de 2002): 39–43. http://dx.doi.org/10.2166/wst.2002.0453.

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Bacteriophages were isolated from a laboratory scale enhanced biological phosphate removing (EBPR) activated sludge process, and their host range was examined. Bacterial isolates to host the bacteriophages were isolated from the EBPR activated sludge process. Bacteriophages were eluted from the EBPR activated sludge, enriched by incubation with the bacterial isolates, and then tested for plaque formation on each of the bacterial isolates. Out of 12 bacterial isolates isolated, 4 supported plaque formation. Four bacteriophages were obtained from the plaques. The host range test was conducted with the combination of the bacteriophage isolates and the bacterial isolates. Three of the bacteriophages were found to form plaques on more than one host, and one of them formed plaques on both Gram +ve and Gram −ve bacterial isolates. Two of the four bacteriophages failed to form plaques on their original bacterial host, indicating the existence of mutation on either both or one of the host and the bacteriophage. This study strongly suggests that bacteriophages are an active part of the activated sludge microbial ecosystem, having very complex interaction with their host bacteria.

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Zhang, Peipei, József Baranyi y Mark Tamplin. "Interstrain Interactions between Bacteria Isolated from Vacuum-Packaged Refrigerated Beef". Applied and Environmental Microbiology 81, n.º 8 (6 de febrero de 2015): 2753–61. http://dx.doi.org/10.1128/aem.03933-14.

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ABSTRACTThe formation of bacterial spoilage communities in food is influenced by both extrinsic and intrinsic environmental factors. Although many reports describe how these factors affect bacterial growth, much less is known about interactions among bacteria, which may influence community structure. This study investigated interactions among representative species of bacteria isolated from vacuum-packaged (VP) beef. Thirty-nine effectors and 20 target isolates were selected, representing 10 bacterial genera:Carnobacterium,Pseudomonas,Hafnia,Serratia,Yersinia,Rahnella,Brochothrix,Bacillus,Leuconostoc, andStaphylococcus. The influence of live effectors on growth of target isolates was measured by spot-lawn agar assay and also in liquid culture medium broth using live targets and effector cell-free supernatants. Inhibition on agar was quantified by diameter of inhibition zone and in broth by measuring detection time, growth rate, and maximum population density. A number of interactions were observed, with 28.6% of isolates inhibiting and 4.2% promoting growth. The majority ofPseudomonasisolates antagonized growth of approximately one-half of target isolates. TwoBacillusspp. each inhibited 16 targets. Among lactic acid bacteria (LAB),Carnobacterium maltaromaticuminhibited a wider range of isolates compared to other LAB. The majority of effector isolates enhancing target isolate growth were Gram-negative, includingPseudomonasspp. andEnterobacteriaceae. These findings markedly improve the understanding of potential interactions among spoilage bacteria, possibly leading to more mechanistic descriptions of bacterial community formation in VP beef and other foods.

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Majeed, Huda Zuheir, Faris Nabeeh Jaafar, Mohammed Twffeek Abdul Hussein, Ashraf Sami Hassan, Nadia Kamil Bashar y Anaam Hameed Batah. "Detection Antibiotic Resistance of Enviromental Bacterial Strains". JOURNAL OF UNIVERSITY OF BABYLON for Pure and Applied Sciences 26, n.º 7 (15 de mayo de 2018): 54–62. http://dx.doi.org/10.29196/jubpas.v26i7.1372.

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

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Kadhim, Shurooq Rayyis. "Detection of The Antibacterial Activity of Bacteriocin from Local Isolates of Pseudomonas fluorescens Against Gram Positive Bacteria". Al Mustansiriyah Journal of Pharmaceutical Sciences 14, n.º 1 (1 de junio de 2014): 74–78. http://dx.doi.org/10.32947/ajps.v14i1.129.

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The antibacterial activity of local isolates of Pseudomonas fluorescens (P1and P2) were tested against some pathogenic bacteria, Staphylococcus aureus, S. epidermidis, Streptococcus faecalis, Streptococcus faecium isolated from stool urine and wounds by modified agar block method at 370C for 24 hr. The isolates of P. fluorescens were positive as producer of bacteriocin with a wide inhibition range on growth of gram positive pathogenic bacteria. P1 inhibited the bacterial growth of S. aureus isolates with a range of inhibition zone (12-20) mm. while P2 inhibited the bacterial growth with a range of inhibition zone was (13-22) mm .The range of inhibition zones of S.epidermidis by P1 were (10-18) mm. while the range by P2 was (9-20) mm. The isolate P1 inhibited the growth of all the tested isolates of S. faecalis with a range of inhibition zone between (12-19) mm. The range of inhibition zones of S. faecalis by P2 were (10-18) mm. The bacterial growth of S. faecium isolates were inhibited by P1 with a range of (15-19) mm. and (16-19) mm. with P2. Agar block method was suitable and easy for screening of bacteriocin production from this bacterium.

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Pacholak, Amanda, Wojciech Smułek, Agnieszka Zgoła-Grześkowiak y Ewa Kaczorek. "Nitrofurantoin—Microbial Degradation and Interactions with Environmental Bacterial Strains". International Journal of Environmental Research and Public Health 16, n.º 9 (30 de abril de 2019): 1526. http://dx.doi.org/10.3390/ijerph16091526.

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The continuous exposure of living organisms and microorganisms to antibiotics that have increasingly been found in various environmental compartments may be perilous. One group of antibacterial agents that have an environmental impact that has been very scarcely studied is nitrofuran derivatives. Their representative is nitrofurantoin (NFT)—a synthetic, broad-spectrum antibiotic that is often overdosed. The main aims of the study were to: (a) isolate and characterize new microbial strains that are able to grow in the presence of NFT, (b) investigate the ability of isolates to decompose NFT, and (c) study the impact of NFT on microbial cell properties. As a result, five microbial species were isolated. A 24-h contact of bacteria with NFT provoked modifications in microbial cell properties. The greatest differences were observed in Sphingobacterium thalpophilum P3d, in which a decrease in both total and inner membrane permeability (from 86.7% to 48.3% and from 0.49 to 0.42 µM min−1) as well as an increase in cell surface hydrophobicity (from 28.3% to 39.7%) were observed. Nitrofurantoin removal by selected microbial cultures ranged from 50% to 90% in 28 days, depending on the bacterial strain. Although the isolates were able to decompose the pharmaceutical, its presence significantly affected the bacterial cells. Hence, the environmental impact of NFT should be investigated to a greater extent.

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Tesis sobre el tema "Environmental bacterial isolates"

Clauson, John. "Cryptococcus neoformans Serotype Groups Found in Clinical and Environmental Isolates". TopSCHOLAR®, 1993. http://digitalcommons.wku.edu/theses/1888.

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Cryptococcus neoformans is an encapsulated yeast responsible for severe meningoencephalitis. The importance of epidemiological studies on cryptococcosis has increased since the beginning of the AIDS epidemic. C. neoformans exists in two varieties containing four serotypes, C. neoformans var. neoformans (serotypes A and D) and C. neoformans var. gattii (serotypes B and C). Locally C. neoformans var. neoformans has been associated with pigeon feces during those months having an average temperature of 64.2°F j(17.8°C) and above. Clinical and environmental isolates of C. neoformans obtained from regional hospitals and environmental samplings, respectively, have been grouped into their variety status utilizing canavanine-glycine-bromthymol blue agar. Polyclonal antisera against C. neoformans serotypes A, B, C and D were isolated from challenged rabbits. Serotyping C. neofromans isolates using the polyclonal antisera resulted in 57% (20 of 35) of the serotypes confirmed with a direct immunofluorescent assay utilizing a single monoclonal antibody (E1). Data from the immunofluorescence assay suggest all C. neoformans obtained from regional hospitals (26 of 26) and those isolated from the environment (9 of 9) belong to the A serotype group. These data have provided information leading to the origin of infection for cryptococcosis in our region, which may be beneficial to immunocompromised individuals.

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Gerard, Jeffery M. "Antibiotic secondary metabolites of bacteria isolated from the marine environment". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25055.pdf.

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Feio, Maria Jose Faria. "Characterisation and identification of two novel species of sulphate-reducing bacteria from marine environments". Thesis, University of Portsmouth, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327002.

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This study describes the characterisation and identification of two species of sulphate-reducing bacteria isolated from marine environments. The isolate coded Ind 1 was recovered from the heavily corroded hull of an oil storage vessel moored off the Indonesian coast. An isolate, referred to as Al 1, originated from a soured oil reservoir in Alaska. Observations using microscopy (light, scanning electron and atomic force) revealed that cells were Gram-negative, rod-shaped and very motile. Physiological characterisation, analysis of the fatty acid profiles and partial and full 16S rRNA sequencing demonstrated strong similarities between the two species and members of the Desulfovibrio genus. The position of the strains within phylogenetic trees showed Al 1 clustering closely with Desulfovibrio vietnamensis. Ind 1 revealed a high degree of similarity with both Desulfovibrio gigas and Desulfovibrio gabonensis and these three strains formed a separate cluster in the delta subdivision of the Proteobacteria. However, whole-cell protein profiles and Fourier-transform infrared spectroscopy studies showed that there is enough dissimilarity between the two isolates and the remaining species of the genus Desulfovibrio to consider Al 1 and Ind 1 as new separate species. Purification, physico-chemical and spectroscopic characterisation of the key enzymes involved in the sulphate metabolism was carried out for both isolates. Nuclear magnetic resonance and electron paramagnetic resonance studies revealed that the proteins of Al 1 and Ind 1 exhibited various features in common with their counterparts from other members of the genus Desulfovibrio. In particular, proteins from Ind 1 showed many similarities with the enzymes previously described for D. gigas. Based on the obtained results, the classification of Ind 1 as Desulfovibrio indonensiensis sp. nov. and Al 1 as Desulfovibrio alaskensis sp. nov. are proposed. The overall results highlight the complexity of the relationship between cell physiology and the organisms' environmental impact.

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GIBBS, SHAWN G. "ANTIBIOTIC RESISTANT BACTERIA ISOLATED FROM THE AIR OF SWINE CONFINEMENT OPERATIONS". University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin974839805.

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Morelos, M., Phillip R. Scheuerman y G. Gist. "Antibiotic Resistant Bacteria Isolated from German Cockroaches Collected from a Hospital Laundry Facility". Digital Commons @ East Tennessee State University, 1989. https://dc.etsu.edu/etsu-works/2887.

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Yooyen, Juthatip. "Degradation of volatile organic compounds by various bacteria isolated from the environment". Thesis, University of Warwick, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425992.

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Ternström, Anders. "Classification, grouping and identification of bacteria isolated from food and the environment". Lund : Dept. of Food Technology, Laboratory of hygiene and taxonomy, Lund University, 1992. http://catalog.hathitrust.org/api/volumes/oclc/39697487.html.

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Sislak, Christine Demko. "Novel Thermophilic Bacteria Isolated from Marine Hydrothermal Vents". PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1486.

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As part of a large study aimed at searching for patterns of diversity in the genus Persephonella along the north to south geochemical gradient of the ELSC, ten novel strains of Alphaproteobacteria were isolated unexpectedly. Using defined media under microaerophilic conditions to enrich for Persephonella from chimney samples collected at the seven vent fields on the ELSC and the dilution to extinction by serial dilution method to purify cultures, a total of ten strains belonging to the Alphaproteobacteria were isolated. Two of these isolates, designate MN-5 and TC-2 were chosen for further characterization and are proposed as two new species of a novel genus to be namedThermopetrobacter. Both strains are aerobic, capable of chemoautotrophic growth on hydrogen and grow best at 55°C, pH 6 and 3.0% NaCl. Strain MN-5 is capable of heterotrophic growth on pyruvate and malate and TC-2 is only able to grow heterotrophically with pyruvate. The GC content of MN-5 is 69.1 and TC-2 is 67 mol%. GenBank BLAST results from the 16S rRNA gene reveal the most closely related sequence to MN-5 is 90% similar and the most closely related sequence to strain TC-2 is 89% similar. Sampling at a shallow marine vent on the coast of Vulcano Island, Italy in 2007 led to the isolation of a novel species of Hydrogenothermus, a genus within the Hydrogenothermaceae family. This isolate, designated NV1, represents the secondHydrogenothermusisolated from a shallow marine vent. NV1 cells are rod-shaped, approximately 1.5μm long and 0.7μm wide, motile by means of a polar flagellum and grow singularly or in short chains. Cells grow chemoautotrophically using hydrogen or thiosulfate as electron donors and oxygen as the sole electron acceptor. Growth was observed between 45 and 75°C with an optimum of 65°C (doubling time 140 min), pH 4.0-6.5 and requires NaCl (0.5-6.0% w/v). The G+C content of total DNA is 32 mol%.

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Dávila, Céspedes Antonio [Verfasser]. "Metabolites of bacteria isolated from marine environments: chemistry and bioactivities / Antonio Dávila Céspedes". Bonn : Universitäts- und Landesbibliothek Bonn, 2018. http://d-nb.info/119893333X/34.

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Bumadian, Mohamed M. "Molecular identification and physiological characterisation of extremely halotolerant bacteria isolated from a freshwater environment". Thesis, University of Sheffield, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548562.

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Libros sobre el tema "Environmental bacterial isolates"

Hansen, Edward Jon. The transformation of tetrachloromethane under denitrifying conditions by a subsurface bacterial consortium and its isolates. 1990.

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Kirchman, David L. Genomes and meta-omics for microbes. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0005.

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The sequencing of entire genomes of microbes grown in pure cultures is now routine. The sequence data from cultivated microbes have provided insights into these microbes and their uncultivated relatives. Sequencing studies have found that bacterial genomes range from 0.18 Mb (intracellular symbiont) to 13 Mb (a soil bacterium), whereas genomes of eukaryotes are much bigger. Genomes from eukaryotes and prokaryotes are organized quite differently. While bacteria and their small genomes often grow faster than eukaryotes, there is no correlation between genome size and growth rates among the bacteria examined so far. Genomic studies have also highlighted the importance of genes exchanged (“horizontal gene transfer”) between organisms, seemingly unrelated, as defined by rRNA gene sequences. Microbial ecologists use metagenomics to sequence all microbes in a community. This approach has revealed unsuspected physiological processes in microbes, such as the occurrence of a light-driven proton pump, rhodopsin, in bacteria (dubbed proteorhodopsin). Genomes from single cells isolated by flow cytometry have also provided insights about the ecophysiology of both bacteria and protists. Oligotrophic bacteria have streamlined genomes, which are usually small but with a high fraction of genomic material devoted to protein-encoding genes, and few transcriptional control mechanisms. The study of all transcripts from a natural community, metatranscriptomics, has been informative about the response of eukaryotes as well as bacteria to changing environmental conditions.

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Capítulos de libros sobre el tema "Environmental bacterial isolates"

Moll, Henry, Laura Lütke y Andrea Cherkouk. "Bacterial Diversity in Clay and Actinide Interactions with Bacterial Isolates in Relation to Nuclear Waste Disposal". En Radionuclides in the Environment, 209–29. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-22171-7_12.

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Saha, Mousumi, Agniswar Sarkar y Bidyut Bandyopadhyay. "Phylogenetic Characterization of Nitrifying Bacteria Isolated from East Kolkata Wetland". En Proceedings of the Conference BioSangam 2022: Emerging Trends in Biotechnology (BIOSANGAM 2022), 114–22. Dordrecht: Atlantis Press International BV, 2022. http://dx.doi.org/10.2991/978-94-6463-020-6_12.

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AbstractEast Kolkata Wetland (EKW) is an “International Ramsar Site”, famous for broad biodiversity and insightful use of sewage for aquaculture. Native nitrifying bacteria of EKW play a significant role in maintaining water quality and controlling environmental pollution by converting ammonia into nitrate in wastewater. Therefore, the characterization of nitrifying bacteria is important in EKW. Thus, the main focus of this research was to identify and characterize the nitrifying bacteria, investigating their phylogeny and diversity in EKW. 16S rRNA and functional genes analysis may help in the proper evaluation of composition and distribution of nitrifying bacteria in some water bodies in EKW, which has not yet been explored. Molecular and phylogenetic characterization was targeted and achieved through 16S rRNA and functional gene analysis, followed by computational estimation. Resulted sequences were analysed to gain insight into the knowledge for global and local taxonomic orientation. Hence, a model can be created for characterizing the dynamics of nitrifying bacteria in wastewater treatment and sustainable aquaculture in different water bodies of EKW. Graphical Abstract

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Toussaint, M., J. M. D. Steen, P. C. Slot, J. Wolf, J. E. M. Beurskens y J. R. Parsons. "Reductive Dechlorination of Chlorinated Dibenzo-p-Dioxins by a Bacterial Consortium Isolated from Lake Ketelmeer Sediment". En Soil & Environment, 423–24. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0415-9_113.

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Tsuruta, Takehiko. "Biosorption of Uranium for Environmental Applications Using Bacteria Isolated from the Uranium Deposits". En Microbes and Microbial Technology, 267–81. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-7931-5_11.

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Benzina-Tihar, Farida, Thanina Chaouche, Mohamed Khoja y Hakima Mohand-Kaci Oulebsir. "Characterization of Bacteria Isolated from Hydrocarbon Contaminated Soils and Producers of Biosurfactants". En Recent Advances in Environmental Science from the Euro-Mediterranean and Surrounding Regions, 281–82. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-70548-4_89.

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Narita, Masaru y Ginro Endo. "Characteristics and Mechanisms of Mercury Resistance of the Anaerobic Bacteria Isolated from Mercury Polluted Sea Bottom Sediment". En Environmental Monitoring and Biodiagnostics of Hazardous Contaminants, 155–65. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-017-1445-7_13.

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Fle, Manfred G., Jan L. W. Rademaker, Frank J. Louws, James Versalovic y Frans J. De Bruijn. "Section 3 update: Genotyping of bacterial isolates from the environment using Low-Molecular-Weight RNA fingerprints". En Molecular Microbial Ecology Manual, 2489–512. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-2177-0_305.

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Strietelmeier, Betty A., Jeffrey B. Gillow, Cleveland J. Dodge, Maria E. Pansoy-Hjelvik, Suzanne M. Kitten, Patricia A. Leonard, Inés R. Triay, A. J. Francis y Hans W. Papenguth. "Toxicity of Actinides to Bacterial Strains Isolated from the Waste Isolation Pilot Plant (WIPP) Environment". En Actinide Speciation in High Ionic Strength Media, 261–68. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4419-8690-0_18.

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Chen, Nan, Chunyuan Wu, Qinfen Li y Xiao Deng. "Kocuria Rosea HN01: A Newly Discovered Alkaliphilic Humic-Reducing Bacteria Isolated from Cassava Dregs Composting". En Functions of Natural Organic Matter in Changing Environment, 869–71. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-5634-2_158.

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Makhloufi, Souad, Serra Djaboub, Abdallah Moussaoui y Sliman Benouis. "Antifungal Activity of Isolated Lactic Acid Bacteria Strain from Wheat Against Some Fusarium graminearum Strains". En Recent Advances in Environmental Science from the Euro-Mediterranean and Surrounding Regions, 345–46. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-70548-4_109.

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Actas de conferencias sobre el tema "Environmental bacterial isolates"

Siripornadulsil, Surasak y Wilailak Siripornadulsil. "Characterization of Cadmium-Resistant Bacteria and Their Application for Cadmium Bioremediation". En ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16072.

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On a global basis, trace-metal pollution is one of the most pervasive environmental problems. It is particularly difficult to prevent or clean up because the metals are toxic in their elemental form and cannot be decomposed. Bioremediation has been shown to be a powerful system for heavy metal pollution clean up and prevention. In this work, we characterized the cadmium (Cd)-resistant bacteria isolated from rice field soil downstream from zinc (Zn) mineralized area which the owners were contaminated at high level of cadmium content in their blood (>10 μgCd/g creatinine). We found that all 24 isolated bacteria tolerated toxic Cd concentrations (2,500 μM). In order to determine whether the Cd toxicity affected the growth of isolated bacteria, we grew the isolated bacterial cells in the absence and presence of toxic concentrations of CdCl2 (500 μM). In the absence of Cd, all isolated bacterial cells grew slightly better than in the presence of toxic concentrations of Cd. In addition, the Cd binding capacity of all isolated bacteria were very high, ranging from 6.38 to 9.38 log[Cd(atom)]/cell when grown in the presence of 500 μM CdCl2. Furthermore, the stability of Cd-bacteria complex of all isolated bacteria was affected by 1mM EDTA. When grown in the presence of 500 μM CdCl2, Cd-resistant isolates S2500-6, -8, -9, -15, -17, -18, -19, and -22 increasingly produced proteins containing cysteine (SH-group) (from 1.3 to 2.2 times) as well as 11 isolates of Cd-resistant bacteria, including S2500-1, -2, -3, -5, -6, -8, -9, -11, -16, -20, and -21, increasingly produced inorganic sulfide (1.5 to 4.7 times). Furthermore, the Sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy studies indicated that Cd-resistant isolated S2500-3 precipitated amounts of cadmium sulfide (CdS), when grown in the presence of 500 μM CdCl2. The results suggested that these Cd-resistant bacteria have potential ability to precipitate a toxic soluble CdCl2 as nontoxic insoluble CdS. Interestingly, Cd-resistant bacteria isolated S2500-3, -8, -9,and -20 increased cadmium tolerance of Thai jasmine rice (Kao Hom Mali 105) when grown in the presence of 200 μM CdCl2. These 4 isolates also decreased cadmium concentration accumulation in Kao Hom Mali 105 plant at 61, 9, 6, and 17%, respectively when grown in the presence of 200 μM CdCl2. They were identified by 16S rDNA sequence analysis and classified as Cupriavidus taiwanensis (isolate S2500-3) and Pseudomonas aeruginosa (isolates S2500-8, -9, and -20).

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Marco-Noales, Ester, Mónica Ordax, Neus Garcias-Bonet, María M. López, Núria Marbá y Carlos M. Duarte. "Degradative potential of marine bacterial isolates from the aquatic plant Posidonia oceanica". En Proceedings of the II International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2007). WORLD SCIENTIFIC, 2009. http://dx.doi.org/10.1142/9789812837554_0043.

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Abdel Samad, Rim, Zulfa Al Disi, Mohammad Ashfaq y Nabil Zouari. "The use of Principle Component Analysis and MALDI-TOF MS for the differentiation of mineral forming Virgibacillus and Bacillus species isolated from Sabkhas". En Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0069.

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Occurrence of mineral forming and other bacteria in mats is well demonstrated. However, their high diversity shown by ribotyping was not explained, although it could explain the diversity of formed minerals. Common biomarkers as well as phylogenic relationships are useful tools to clustering the isolates and predict their potential role in the natural niche. In this study, combination of MALDI-TOF MS with PCA was shown a powerful tool to categorize 35 mineral forming bacterial strains isolated from Dohat Fshaikh sabkha, at northwest of Qatar (23 from decaying mats and 12 from living ones). 23 strains from decaying mats belong to Virgibacillus genus as identified by ribotyping and are shown highly involved in formation of protodolomite and a diversity of minerals. They were used as internal references in categorization of sabkha bacteria. Combination of isolation of bacteria on selective mineral forming media, their MALDI TOF MS protein profiling and PCA analysis established their relationship in a phyloproteomic based on protein biomarkers including m/z 4905, 3265, 5240, 6430, 7765, and 9815. PCA analysis clustered the studied strains into 3 major clusters, showing strong correspondence to the 3 phyloproteiomic groups that were established by the dendrogram. Both clustering analysis means have evidently demonstrated a relationship between known Virgibacillus strains and other related bacteria based on profiling of their synthesized proteins. Thus, larger populations of bacteria in mats can be easily screened for their potential to exhibit certain activities, which is of ecological, environmental and biotechnological significance.

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Maltseva, S. V., A. S. Yakubovich, E. R. Gritskevitch, I. E. Buchenkov y A. G. Sysa. "ANTAGONISTIC ACTIVITY OF BACTERIA OF THE GENUS BACILLUS ISOLATED FROM SOILS UNDER PROLONGED EXPOSURE TO IONIZING RADIATION IN RELATION TO COLIMORPHOUS BACTERIA". En SAKHAROV READINGS 2022: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute of Belarusian State University, 2022. http://dx.doi.org/10.46646/sakh-2022-1-299-302.

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This paper presents the results of studies of the antagonistic activity of bacteria of the genus Bacillus (Bacillus subtilis, Bacillus thuringiensis, Bacillus mycoides and Bacillus cereus) under prolonged exposure to ionizing radiation in relation to bacteria of the E. coli group. It was found that bacteria of the genus Bacillus exhibit antagonistic activity of varying degrees of severity. It was found that the bacterial strains Bacillus subtilis, Bacillus thuringiensis and Bacillus mycoides showed a high level of antagonistic activity. Low antagonistic activity was characteristic of Bacillus cereus bacteria.

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Gordeev, A., A. Kamalova y S. Selivanovskaya. "SCREENING OF THE ABILITY OF RHIZOSPHERE BACTERIA TO PRODUCE BIOSURFACTANTS". En 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/5.1/s20.049.

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Surfactants produced by microorganisms, known as biosurfactants, have recently found wide application in the industry, from cosmetology to oil processing. Biosurfactants are more tolerant to extreme environmental conditions and less hazardous for the environment as compared with their chemical analogues. Despite on the fact that many biosurfactant producers have been recently isolated and described, the challenge to explore new producers still remains very urgent. In the present study, the isolates obtained from rhizosphere soil were screened towards their abilities to emulsify oil and to decrease interface tension between oil and water. As a source of potential producers, rhizosphere soil of Latuca sativa was used. 12 rapidly growing isolates were cultivated in glycerol nitrate medium at 28? for 72 h. Emulsification activity (E24) and drop collapse tests were used to screen the abilities of the supernatants obtained. The lowest E24 was registered for 7 of 12 isolates (from 0% to 43%), while the highest one was registered for 5 from 12 isolates (50%). All these 5 isolates (12b, 19a, 20b, 23a and 26b) demonstrated high efficiency in drop collapse test as well (maximal scores in qualitative test). Besides, 3 other isolates were characterized as the most efficient in the drop collapse test (2c, 9a and 17a).

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Taura, Usman, Sara Al-Araimi, Saif Al-Bahry, Yahya Al-Wahaibi y Lujain Al-Rashdi. "Isolation of Autochthonous Consortium for the Bioremediation of Oil Contaminated Produced Water". En SPE Nigeria Annual International Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/212024-ms.

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Abstract In this research, we isolated indigenous bacteria capable of remediating oil-contaminated produced water in an efficient, cost-effective and environmentally friendly manner. Nine different produced water samples were collected from Omani oil fields and analysed for their physicochemical properties and microbial communities present. Different technologies were performed to extract the DNA of the microbial community cultured in different media. Metagenomic classification of the microbial community showed that the abundant genera are the Acidithiobacillus, Proteinphilum and Marinobacter. The isolated microbes that showed the highest efficiency in oil degradation were further evaluated for liquid-based biodegradation as well as in naturally occurring and artificially contaminated soil. Fourteen bacteria samples were found to be efficient in bioremediating the three environments tested. In the liquid-based media, the isolates were able to degrade the heavy oil carbon chains (C14-C20) by at least 50% after 1 week period, while some of the most potent isolates have achieved more than 95% or completely degraded all the hydrocarbon chains. Similarly, in the naturally contaminated soil, the isolates demonstrated a complete degradation of the lighter carbon molecules from C10-C16 and also achieved a higher than 90% degradation for the heavier components. Likewise, the isolates have exhibited similar biodegradation ability when exposed to an induced contaminated soil where all the lower carbon chains (C12-C17) were mostly degraded by the microbes in the samples.

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Airil, Muhammad Syukri. "Isolation of Bioluminescence Bacterium from Marine Fish and Amplification of Luciferase (lux AB) Gene". En INTERNATIONAL CONFERENCE ON BIOLOGICAL RESEARCH AND APPLIED SCIENCE. Jinnah University for Women, Karachi,Pakistan, 2022. http://dx.doi.org/10.37962/ibras/2022/10-13.

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Bioluminescence bacteria (BLB) are the most abundant and widely distributed light-emitting organisms that can be found in the marine environment. They are suitable for detecting pollution or integrated into bioluminescent imaging due to their ability to luminesce. However, there are limited studies regarding bioluminescent bacteria in terms of distribution and species present in Malaysia. This study aims to isolate BLB and amplify the luciferase (luxAB) genes. Bioluminescent bacteria were isolated from the guts of marine fish, Selaroidesleptolepis and streak onto luminescence agar (LA). The brightest luminous colony present in the dark was marked and streaked again obtain a pure colony. Then, the pure culture of the colony was subjected to genomic extraction before luxAB genes amplification and phylogenetic analysis. As a result, BLB were successfully isolated and identified to be Photobacteriumleiognathis train SYA2 (MZ491870.1). Genes encoding for luciferase enzyme were also amplified and sequenced with the size of luxA and luxB were 767 bp and 943 bp, respectively. Pairwise distance showed that the isolate has the highest similarity to P. leiognathi (DQ790853) with 99.66% and the lowest similarity to P. kishitanii (AY642227) with 69.84%. The information about the isolate will contribute to the distribution of BLB in Malaysia as well as potential of BLB as a biosensor and bioreporter.

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Chou, Fong-In, Chia-Chin Li, Tzung-Yuang Chen y Hsiao-Wei Wen. "Microbial Occurrence in Bentonite-Based Buffer Materials of a Final Disposal Site for Low Level Radioactive Waste in Taiwan". En ASME 2010 13th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2010. http://dx.doi.org/10.1115/icem2010-40284.

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This research addresses the potential of microbial implications in bentonite for use as a buffer and backfill material in final disposal site for low-level radioactive waste (LLRW) in Taiwan, where has a special island-type climate. Microbe activities naturally present in this site were analyzed, and buffer materials (BM) consisted of 100%, 70% or 50% bentonite were prepared for laboratory studies. A total of 39 microbial strains were isolated, and the predominant strains included four bacterial, one yeast and four fungal strains. Growth inhibition was not detected in any tested strain cultured in a radiation field with a dose rate of 0.2 Gy/h. Most of the isolated strains grew under a dose rate of 1.4 Gy/h. The D10 values of the tested strains ranged from 0.16 to 2.05 kGy. The mycelia of tested fungal strains could spread over 5 cm during six months of inoculation in BM. The spreading activity of the tested bacteria was less than that of the fungi. Moreover, biofilms were observed on the surfaces of the BM. Since a large and diverse population of microbes is present in Taiwan, microbes may contribute to the mobilization of radionuclides in the disposal site.

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Fikó, Dezső-Róbert, Erika Kovács, Szabolcs Szilveszter, Tamás Felföldi y István Máthé. "Phenol Degradation Potential of Bacteria Isolated From Extreme Habitats". En The World Congress on Civil, Structural, and Environmental Engineering. Avestia Publishing, 2016. http://dx.doi.org/10.11159/awspt16.132.

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Mudawaroch, Roisu, Setiyono Setiyono, Lies Yusiati y Edi Suryanto. "Fermentation Kinetics of Isolate Lactic Acid Bacteria Probiotic BR 12 and BR 17 were Isolated from Broiler Chicken Meat". En International Conference on Environmental Awareness for Sustainable Development in conjunction with International Conference on Challenge and Opportunities Sustainable Environmental Development, ICEASD & ICCOSED 2019, 1-2 April 2019, Kendari, Indonesia. EAI, 2019. http://dx.doi.org/10.4108/eai.1-4-2019.2287183.

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Informes sobre el tema "Environmental bacterial isolates"

Cytryn, Eddie, Mark R. Liles y Omer Frenkel. Mining multidrug-resistant desert soil bacteria for biocontrol activity and biologically-active compounds. United States Department of Agriculture, enero de 2014. http://dx.doi.org/10.32747/2014.7598174.bard.

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Control of agro-associated pathogens is becoming increasingly difficult due to increased resistance and mounting restrictions on chemical pesticides and antibiotics. Likewise, in veterinary and human environments, there is increasing resistance of pathogens to currently available antibiotics requiring discovery of novel antibiotic compounds. These drawbacks necessitate discovery and application of microorganisms that can be used as biocontrol agents (BCAs) and the isolation of novel biologically-active compounds. This highly-synergistic one year project implemented an innovative pipeline aimed at detecting BCAs and associated biologically-active compounds, which included: (A) isolation of multidrug-resistant desert soil bacteria and root-associated bacteria from medicinal plants; (B) invitro screening of bacterial isolates against known plant, animal and human pathogens; (C) nextgeneration sequencing of isolates that displayed antagonistic activity against at least one of the model pathogens and (D) in-planta screening of promising BCAs in a model bean-Sclerotiumrolfsii system. The BCA genome data were examined for presence of: i) secondary metabolite encoding genes potentially linked to the anti-pathogenic activity of the isolates; and ii) rhizosphere competence-associated genes, associated with the capacity of microorganisms to successfully inhabit plant roots, and a prerequisite for the success of a soil amended BCA. Altogether, 56 phylogenetically-diverse isolates with bioactivity against bacterial, oomycete and fungal plant pathogens were identified. These strains were sent to Auburn University where bioassays against a panel of animal and human pathogens (including multi-drug resistant pathogenic strains such as A. baumannii 3806) were conducted. Nineteen isolates that showed substantial antagonistic activity against at least one of the screened pathogens were sequenced, assembled and subjected to bioinformatics analyses aimed at identifying secondary metabolite-encoding and rhizosphere competence-associated genes. The genome size of the bacteria ranged from 3.77 to 9.85 Mbp. All of the genomes were characterized by a plethora of secondary metabolite encoding genes including non-ribosomal peptide synthase, polyketidesynthases, lantipeptides, bacteriocins, terpenes and siderophores. While some of these genes were highly similar to documented genes, many were unique and therefore may encode for novel antagonistic compounds. Comparative genomic analysis of root-associated isolates with similar strains not isolated from root environments revealed genes encoding for several rhizospherecompetence- associated traits including urea utilization, chitin degradation, plant cell polymerdegradation, biofilm formation, mechanisms for iron, phosphorus and sulfur acquisition and antibiotic resistance. Our labs are currently writing a continuation of this feasibility study that proposes a unique pipeline for the detection of BCAs and biopesticides that can be used against phytopathogens. It will combine i) metabolomic screening of strains from our collection that contain unique secondary metabolite-encoding genes, in order to isolate novel antimicrobial compounds; ii) model plant-based experiments to assess the antagonistic capacities of selected BCAs toward selected phytopathogens; and iii) an innovative next-generation-sequencing based method to monitor the relative abundance and distribution of selected BCAs in field experiments in order to assess their persistence in natural agro-environments. We believe that this integrated approach will enable development of novel strains and compounds that can be used in large-scale operations.

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Wackett, Lawrence, Raphi Mandelbaum y Michael Sadowsky. Bacterial Mineralization of Atrazine as a Model for Herbicide Biodegradation: Molecular and Applied Aspects. United States Department of Agriculture, enero de 1999. http://dx.doi.org/10.32747/1999.7695835.bard.

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Atrazine is a broadly used herbicide in agriculture and it was used here as a model to study the biodegradation of herbicides. The bacterium Pseudomonas sp. ADP metabolizes atrazine to carbon dioxide and ammonia and chloride. The genes encoding atrazine catabolism to cyanuric acid were cloned and expressed in Escherichia coli. The genes were designated atzA, atzB and atzC. Each gene was sequenced. The enzyme activities were characterized. AtzA is atrazine chlorohydrolase which takes atrazine to hydroxyatrizine. AtzB is hydroxyatrazine N-ethylaminohydrolase which produces N-isopropylammelide and N-ethylamine. AtzC is N-isopropylammelide N-isopropylaminohydrolase which produces cyanuric acid and N-isopropylamine. Each product was isolated and characterized to confirm their identity by chromatography and mass spectrometry. Sequence analysis indicated that each of the hydrolytic enzymes AtzA, AtzB and AtzC share identity which the aminohydrolase protein superfamily. Atrazine chlorohydrolase was purified to homogeneity. It was shown to have a kcat of 11 s-1 and a KM of 150 uM. It was shown to require a metal ion, either Fe(II), Mn(II) or Co(II), for activity. The atzA, atzB and atzC genes were shown to reside on a broad-host range plasmid in Pseudomonas sp. ADP. Six other recently isolated atrazine-degrading bacteria obtained from Europe and the United States contained homologs to the atz genes identified in Pseudomonas sp. ADP. The identity of the sequences were very high, being greater than 98% in all pairwise comparisons. This indicates that many atrazine-degrading bacteria worldwide metabolize atrazine via a pathway that proceeds through hydroxyatrazine, a metabolite which is non-phytotoxic and non-toxic to mammals. Enzymes were immobilized and used for degradation of atrazine in aqueous phases. The in-depth understanding of the genomics and biochemistry of the atrazine mineralization pathway enabled us to study factors affecting the prevalence of atrazine degradation in various agricultural soils under conservative and new agricultural practices. Moreover, Pseudomonas sp. ADP and/or its enzymes were added to atrazine-contaminated soils, aquifers and industrial wastewater to increase the rate and extent of atrazine biodegradation above that of untreated environments. Our studies enhance the ability to control the fate of regularly introduced pesticides in agriculture, or to reduce the environmental impact of unintentional releases.

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Hutchinson, M. L., J. E. L. Corry y R. H. Madden. A review of the impact of food processing on antimicrobial-resistant bacteria in secondary processed meats and meat products. Food Standards Agency, octubre de 2020. http://dx.doi.org/10.46756/sci.fsa.bxn990.

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For meat and meat products, secondary processes are those that relate to the downstream of the primary chilling of carcasses. Secondary processes include maturation chilling, deboning, portioning, mincing and other operations such as thermal processing (cooking) that create fresh meat, meat preparations and ready-to-eat meat products. This review systematically identified and summarised information relating to antimicrobial resistance (AMR) during the manufacture of secondary processed meatand meat products (SPMMP). Systematic searching of eight literature databases was undertaken and the resultantpapers were appraised for relevance to AMR and SPMMP. Consideration was made that the appraisal scores, undertaken by different reviewers, were consistent. Appraisal reduced the 11,000 initially identified documents to 74, which indicated that literature relating to AMR and SPMMP was not plentiful. A wide range of laboratory methods and breakpoint values (i.e. the concentration of antimicrobial used to assess sensitivity, tolerance or resistance) were used for the isolation of AMR bacteria.The identified papers provided evidence that AMR bacteria could be routinely isolated from SPMMP. There was no evidence that either confirmed or refuted that genetic materials capable of increasing AMR in non-AMR bacteria were present unprotected (i.e. outside of a cell or a capsid) in SPMMP. Statistical analyses were not straightforward because different authors used different laboratory methodologies.However, analyses using antibiotic organised into broadly-related groups indicated that Enterobacteriaceaeresistant to third generation cephalosporins might be an area of upcoming concern in SPMMP. The effective treatment of patients infected with Enterobacteriaceaeresistant to cephalosporins are a known clinical issue. No AMR associations with geography were observed and most of the publications identified tended to be from Europe and the far east.AMR Listeria monocytogenes and lactic acid bacteria could be tolerant to cleaning and disinfection in secondary processing environments. The basis of the tolerance could be genetic (e.g. efflux pumps) or environmental (e.g. biofilm growth). Persistent, plant resident, AMR L. monocytogenes were shown by one study to be the source of final product contamination. 4 AMR genes can be present in bacterial cultures used for the manufacture of fermented SPMMP. Furthermore, there was broad evidence that AMR loci could be transferred during meat fermentation, with refrigeration temperatures curtailing transfer rates. Given the potential for AMR transfer, it may be prudent to advise food business operators (FBOs) to use fermentation starter cultures that are AMR-free or not contained within easily mobilisable genetic elements. Thermal processing was seen to be the only secondary processing stage that served as a critical control point for numbers of AMR bacteria. There were significant linkages between some AMR genes in Salmonella. Quaternary ammonium compound (QAC) resistance genes were associated with copper, tetracycline and sulphonamide resistance by virtue of co-location on the same plasmid. No evidence was found that either supported or refuted that there was any association between AMR genes and genes that encoded an altered stress response or enhanced the survival of AMR bacteria exposed to harmful environmental conditions.

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Eldar, Avigdor y Donald L. Evans. Streptococcus iniae Infections in Trout and Tilapia: Host-Pathogen Interactions, the Immune Response Toward the Pathogen and Vaccine Formulation. United States Department of Agriculture, diciembre de 2000. http://dx.doi.org/10.32747/2000.7575286.bard.

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In Israel and in the U.S., Streptococcus iniae is responsible for considerable losses in various fish species. Poor understanding of its virulence factors and limited know-how-to of vaccine formulation and administration are the main reasons for the limited efficacy of vaccines. Our strategy was that in order to Improve control measures, both aspects should be equally addressed. Our proposal included the following objectives: (i) construction of host-pathogen interaction models; (ii) characterization of virulence factors and immunodominant antigens, with assessment of their relative importance in terms of protection and (iii) genetic identification of virulence factors and genes, with evaluation of the protective effect of recombinant proteins. We have shown that two different serotypes are involved. Their capsular polysaccharides (CPS) were characterized, and proved to play an important role in immune evasion and in other consequences of the infection. This is an innovative finding in fish bacteriology and resembles what, in other fields, has become apparent in the recent years: S. iniae alters surface antigens. By so doing, the pathogen escapes immune destruction. Immunological assays (agar-gel immunodiffusion and antibody titers) confirmed that only limited cross recognition between the two types occurs and that capsular polysaccharides are immunodominant. Vaccination with purified CPS (as an acellular vaccine) results in protection. In vitro and ex-vivo models have allowed us to unravel additional insights of the host-pathogen interactions. S. iniae 173 (type II) produced DNA fragmentation of TMB-8 cells characteristic of cellular necrosis; the same isolate also prevented the development of apoptosis in NCC. This was determined by finding reduced expression of phosphotidylserine (PS) on the outer membrane leaflet of NCC. NCC treated with this isolate had very high levels of cellular necrosis compared to all other isolates. This cellular pathology was confirmed by observing reduced DNA laddering in these same treated cells. Transmission EM also showed characteristic necrotic cellular changes in treated cells. To determine if the (in vitro) PCD/apoptosis protective effects of #173 correlated with any in vivo activity, tilapia were injected IV with #173 and #164 (an Israeli type I strain). Following injection, purified NCC were tested (in vitro) for cytotoxicity against HL-60 target cells. Four significant observations were made : (i) fish injected with #173 had 100-400% increased cytotoxicity compared to #164 (ii) in vivo activation occurred within 5 minutes of injection; (iii) activation occurred only within the peripheral blood compartment; and (iv) the isolate that protected NCC from apoptosis in vitro caused in vivo activation of cytotoxicity. The levels of in vivo cytotoxicity responses are associated with certain pathogens (pathogen associated molecular patterns/PAMP) and with the tissue of origin of NCC. NCC from different tissue (i.e. PBL, anterior kidney, spleen) exist in different states of differentiation. Random amplified polymorphic DNA (RAPD) analysis revealed the "adaptation" of the bacterium to the vaccinated environment, suggesting a "Darwinian-like" evolution of any bacterium. Due to the selective pressure which has occurred in the vaccinated environment, type II strains, able to evade the protective response elicited by the vaccine, have evolved from type I strains. The increased virulence through the appropriation of a novel antigenic composition conforms with pathogenic mechanisms described for other streptococci. Vaccine efficacy was improved: water-in-oil formulations were found effective in inducing protection that lasted for a period of (at least) 6 months. Protection was evaluated by functional tests - the protective effect, and immunological parameters - elicitation of T- and B-cells proliferation. Vaccinated fish were found to be resistant to the disease for (at least) six months; protection was accompanied by activation of the cellular and the humoral branches.

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Shpigel, Nahum Y., Ynte Schukken y Ilan Rosenshine. Identification of genes involved in virulence of Escherichia coli mastitis by signature tagged mutagenesis. United States Department of Agriculture, enero de 2014. http://dx.doi.org/10.32747/2014.7699853.bard.

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Mastitis, an inflammatory response of the mammary tissue to invading pathogenic bacteria, is the largest health problem in the dairy industry and is responsible for multibillion dollar economic losses. E. coli are a leading cause of acute mastitis in dairy animals worldwide and certainly in Israel and North America. The species E. coli comprises a highly heterogeneous group of pathogens, some of which are commensal residents of the gut, infecting the mammary gland after contamination of the teat skin from the environment. As compared to other gut microflora, mammary pathogenic E. coli (MPEC) may have undergone evolutionary adaptations that improve their fitness for colonization of the unique and varied environmental niches found within the mammary gland. These niches include competing microbes already present or accompanying the new colonizer, soluble and cellular antimicrobials in milk, and the innate immune response elicited by mammary cells and recruited immune cells. However, to date, no specific virulence factors have been identified in E. coli isolates associated with mastitis. The original overall research objective of this application was to develop a genome-wide, transposon-tagged mutant collection of MPEC strain P4 and to use this technology to identify E. coli genes that are specifically involved in mammary virulence and pathogenicity. In the course of the project we decided to take an alternative genome-wide approach and to use whole genomes bioinformatics analysis. Using genome sequencing and analysis of six MPEC strains, our studies have shown that type VI secretion system (T6SS) gene clusters were present in all these strains. Furthermore, using unbiased screening of MPEC strains for reduced colonization, fitness and virulence in the murine mastitis model, we have identified in MPEC P4-NR a new pathogenicity island (PAI-1) encoding the core components of T6SS and its hallmark effectors Hcp, VgrG and Rhs. Next, we have shown that specific deletions of T6SS genes reduced colonization, fitness and virulence in lactating mouse mammary glands. Our long-term goal is to understand the molecular mechanisms of host-pathogen interactions in the mammary gland and to relate these mechanisms to disease processes and pathogenesis. We have been able to achieve our research objectives to identify E. coli genes that are specifically involved in mammary virulence and pathogenicity. The project elucidated a new basic concept in host pathogen interaction of MPEC, which for the best of our knowledge was never described or investigated before. This research will help us to shed new light on principles behind the infection strategy of MPEC. The new targets now enable prevalence and epidemiology studies of T6SS in field strains of MPEC which might unveil new geographic, management and ecological risk factors. These will contribute to development of new approaches to treat and prevent mastitis by MPEC and perhaps other mammary pathogens. The use of antibiotics in farm animals and specifically to treat mastitis is gradually precluded and thus new treatment and prevention strategies are needed. Effective mastitis vaccines are currently not available, structural components and effectors of T6SS might be new targets for the development of novel vaccines and therapeutics.

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