Thematische Bibliographien / Oligotrophic bacteria

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Auswahl der wissenschaftlichen Literatur zum Thema „Oligotrophic bacteria“

Autor: Grafiati

Veröffentlicht am 18. Mai 2024

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Zeitschriftenartikel zum Thema "Oligotrophic bacteria"

Nakamura, K., M. Shibata und Y. Miyaji. „Substrate Affinity of Oligotrophic Bacteria in Biofilm Reactors“. Water Science and Technology 21, Nr. 8-9 (01.08.1989): 779–90. http://dx.doi.org/10.2166/wst.1989.0281.

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Several biofilm reactors were operated to investigate the substrate affinity of oligotrophic bacteria in the biofilm reactor. The attached oligotrophs were removed from reactors, and substrate affinity was determined in dispersed form. The saturation constant (Ks) of attached oligotrophs for acetate was less than 10 µg-C/l. The apparent Ks (Ksa) values of reactors were also determined to evaluate the performance of reactors,and the effect of specific surface area of packed media on Ksa was investigated at a loading of 0.006 mg-C per cm3-apparent media volume per hour. Larger specific surface area led to smaller Ksa, and 6.9 µg-C/l of Ksa for acetate was obtained with the media having 340 cm2 -surface area per cm -apparent media volume of specific surface area. The bacterial flora in the oligotrophic biofilm was examined, and Pseudomonas was found to be dominant.

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Cottrell, Matthew T., und David L. Kirchman. „Transcriptional Control in Marine Copiotrophic and Oligotrophic Bacteria with Streamlined Genomes“. Applied and Environmental Microbiology 82, Nr. 19 (29.07.2016): 6010–18. http://dx.doi.org/10.1128/aem.01299-16.

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ABSTRACTBacteria often respond to environmental stimuli using transcriptional control, but this may not be the case for marine bacteria such as “CandidatusPelagibacter ubique,” a cultivated representative of the SAR11 clade, the most abundant organism in the ocean. This bacterium has a small, streamlined genome and an unusually low number of transcriptional regulators, suggesting that transcriptional control is low inPelagibacterand limits its response to environmental conditions. Transcriptome sequencing during batch culture growth revealed that only 0.1% of protein-encoding genes appear to be under transcriptional control inPelagibacterand in another oligotroph (SAR92) whereas >10% of genes were under transcriptional control in the copiotrophsPolaribactersp. strain MED152 andRuegeria pomeroyi. When growth levels changed, transcript levels remained steady inPelagibacterand SAR92 but shifted in MED152 andR. pomeroyi. Transcript abundances per cell, determined using an internal RNA sequencing standard, were low (<1 transcript per cell) for all but a few of the most highly transcribed genes in all four taxa, and there was no correlation between transcript abundances per cell and shifts in the levels of transcription. These results suggest that low transcriptional control contributes to the success ofPelagibacterand possibly other oligotrophic microbes that dominate microbial communities in the oceans.IMPORTANCEDiverse heterotrophic bacteria drive biogeochemical cycling in the ocean. The most abundant types of marine bacteria are oligotrophs with small, streamlined genomes. The metabolic controls that regulate the response of oligotrophic bacteria to environmental conditions remain unclear. Our results reveal that transcriptional control is lower in marine oligotrophic bacteria than in marine copiotrophic bacteria. Although responses of bacteria to environmental conditions are commonly regulated at the level of transcription, metabolism in the most abundant bacteria in the ocean appears to be regulated by other mechanisms.

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Lami, Raphaël, Matthew T. Cottrell, Joséphine Ras, Osvaldo Ulloa, Ingrid Obernosterer, Hervé Claustre, David L. Kirchman und Philippe Lebaron. „High Abundances of Aerobic Anoxygenic Photosynthetic Bacteria in the South Pacific Ocean“. Applied and Environmental Microbiology 73, Nr. 13 (11.05.2007): 4198–205. http://dx.doi.org/10.1128/aem.02652-06.

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ABSTRACT Little is known about the abundance, distribution, and ecology of aerobic anoxygenic phototrophic (AAP) bacteria, particularly in oligotrophic environments, which represent 60% of the ocean. We investigated the abundance of AAP bacteria across the South Pacific Ocean, including the center of the gyre, the most oligotrophic water body of the world ocean. AAP bacteria, Prochlorococcus, and total prokaryotic abundances, as well as bacteriochlorophyll a (BChl a) and divinyl-chlorophyll a concentrations, were measured at several depths in the photic zone along a gradient of oligotrophic conditions. The abundances of AAP bacteria and Prochlorococcus were high, together accounting for up to 58% of the total prokaryotic community. The abundance of AAP bacteria alone was up to 1.94 × 105 cells ml−1 and as high as 24% of the overall community. These measurements were consistent with the high BChl a concentrations (up to 3.32 × 10−3 μg liter−1) found at all stations. However, the BChl a content per AAP bacterial cell was low, suggesting that AAP bacteria are mostly heterotrophic organisms. Interestingly, the biovolume and therefore biomass of AAP bacteria was on average twofold higher than that of other prokaryotic cells. This study demonstrates that AAP bacteria can be abundant in various oligotrophic conditions, including the most oligotrophic regime of the world ocean, and can account for a large part of the bacterioplanktonic carbon stock.

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Feng, Cui, Jingyi Jia, Chen Wang, Mengqi Han, Chenchen Dong, Bin Huo, Dapeng Li und Xiangjiang Liu. „Phytoplankton and Bacterial Community Structure in Two Chinese Lakes of Different Trophic Status“. Microorganisms 7, Nr. 12 (27.11.2019): 621. http://dx.doi.org/10.3390/microorganisms7120621.

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Phytoplankton are the primary producers at the basis of aquatic food webs, and bacteria play an important role in energy flow and biochemical cycling in aquatic ecosystems. In this study, both the bacterial and phytoplankton communities were examined in the oligotrophic Lake Basomtso and the eutrophic Lake South (China). The results of this study showed that the phytoplankton density and diversity in the eutrophic lake were higher than those in the oligotrophic lake. Furthermore, Chlorophyta (68%) and Cryptophyta (24%) were the dominant groups in the eutrophic lake, while Bacillariophyta (95%) dominated in the oligotrophic lake. The bacterial communities in the waters and sediments of the two lakes were mainly composed of Proteobacteria (mean of 32%), Actinobacteria (mean of 25%), Bacteroidetes (mean of 12%), and Chloroflexi (mean of 6%). Comparative analysis showed that the abundance of bacteria in the eutrophic lake was higher than that in the oligotrophic lake (p < 0.05), but the bacterial diversity in the oligotrophic lake was higher than that in the eutrophic lake (p < 0.05). Finally, the bacterial abundance and diversity in the sediments of the two lakes were higher than those in the water samples (p < 0.05), and the Latescibacteria and Nitrospinae groups were identified only in the sediments. These results suggest that both the phytoplankton and bacterial communities differed considerably between the oligotrophic lake and the eutrophic lake.

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Lamy, D., C. Jeanthon, J. Ras, F. Van Wambeke, O. Dahan, M. T. Cottrell, D. L. Kirchman und P. Lebaron. „Ecology of aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea“. Biogeosciences Discussions 8, Nr. 1 (12.01.2011): 323–54. http://dx.doi.org/10.5194/bgd-8-323-2011.

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Abstract. Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic prokaryotes able to use both light and organic substrates for energy production. They are widely distributed in coastal and oceanic environments and may contribute significantly to the carbon cycle in the upper ocean. To better understand questions regarding links between the ecology of these photoheterotrophic bacteria and the trophic status of water masses, we examined their horizontal and vertical distribution and the effects of nutrient additions on their growth along an oligotrophic gradient in the Mediterranean Sea. Concentrations of bacteriochlorophyll-a (BChl-a) and AAP bacterial abundance decreased from the western to the eastern basins of the Mediterranean Sea and were linked with concentrations of chlorophyll-a, nutrient and dissolved organic carbon. Inorganic nutrient and glucose additions to surface seawater samples along the oligotrophic gradient revealed that AAP bacteria were nitrogen- and carbon-limited in the ultra-oligotrophic eastern basin. The intensity of the AAP bacterial growth response generally differed from that of the total bacterial growth response. BChl-a quota of AAP bacterial communities was significantly higher in the eastern basin than in the western basin, suggesting that reliance on phototrophy varied along the oligotrophic gradient and that nutrient and/or carbon limitation favors BChl-a synthesis.

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Lauro, Federico M., Diane McDougald, Torsten Thomas, Timothy J. Williams, Suhelen Egan, Scott Rice, Matthew Z. DeMaere et al. „The genomic basis of trophic strategy in marine bacteria“. Proceedings of the National Academy of Sciences 106, Nr. 37 (08.09.2009): 15527–33. http://dx.doi.org/10.1073/pnas.0903507106.

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Many marine bacteria have evolved to grow optimally at either high (copiotrophic) or low (oligotrophic) nutrient concentrations, enabling different species to colonize distinct trophic habitats in the oceans. Here, we compare the genome sequences of two bacteria,Photobacterium angustumS14 andSphingopyxis alaskensisRB2256, that serve as useful model organisms for copiotrophic and oligotrophic modes of life and specifically relate the genomic features to trophic strategy for these organisms and define their molecular mechanisms of adaptation. We developed a model for predicting trophic lifestyle from genome sequence data and tested >400,000 proteins representing >500 million nucleotides of sequence data from 126 genome sequences with metagenome data of whole environmental samples. When applied to available oceanic metagenome data (e.g., the Global Ocean Survey data) the model demonstrated that oligotrophs, and not the more readily isolatable copiotrophs, dominate the ocean's free-living microbial populations. Using our model, it is now possible to define the types of bacteria that specific ocean niches are capable of sustaining.

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Weisse, Thomas, und Erland MacIsaac. „Significance and fate of bacterial production in oligotrophic lakes in British Columbia“. Canadian Journal of Fisheries and Aquatic Sciences 57, Nr. 1 (01.01.2000): 96–105. http://dx.doi.org/10.1139/f99-187.

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We measured bacterial abundance, biomass, production rates, and grazing losses to protozoans in three oligotrophic British Columbia lakes and analyzed bacteria abundance and lake productivity data from 11 other lakes, most fertilized with inorganic nutrients to increase their productivity for juvenile salmon. Bacteria contributed about 24% to the phytoplankton-bacteria carbon biomass in the most ultraoligotrophic lakes, and their relative contribution declined to <11% with increasing lake productivity. At increasingly high nutrient loadings to the lakes, bacteria abundance increased and was closely correlated with phytoplankton biomass and productivity. Heterotrophic nanoflagellate (HNF) abundance was positively correlated with bacterial numbers. Grazing experiments revealed that HNF were the primary pathway for moving bacterial production to higher trophic levels in oligotrophic British Columbia lakes, and predation by the ciliate and rotifer microzooplankton community appeared to exert top-down control over the abundance of HNF and the transfer of carbon from bacteria. The HNF and microzooplankton, in turn, were affected by the abundance of crustacean mesozooplankton, principally copepods in our experiments.

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Kim, Mikyeong, und Mooyoung Han. „Composition and distribution of bacteria in an operating rainwater harvesting tank“. Water Science and Technology 63, Nr. 7 (01.04.2011): 1524–30. http://dx.doi.org/10.2166/wst.2011.410.

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In this study, we investigated the phylogenetic distribution of the bacteria present in an operating rainwater tank by denaturing gradient gel electrophoresis (DGGE), and compared the bacterial composition in rainwater and biofilm from the inlet and outlet of the tank. Seventeen species were identified, the DGGE profiles of which showed a clear difference between the planktonic bacterial community and the community in the biofilm. Most of the bacteria were closely related to fresh water, soil, and biofilm bacteria found in natural environments. The high proportion of Proteobacteria indicates the generally clean oligotrophic nature of the tank water. Biofilm formation is an advantage for bacteria that exist in oligotrophic environments. The groups identified in the biofilm, such as Sphingomonas, Bacillus, and Sphingophyxis, have been demonstrated to degrade certain contaminants and to act as bio-control agents. Thus, biofilm formation in rainwater tanks not only represents a survival strategy for bacteria, but also serves as a natural filter by removing contaminants and bacteria from rainwater.

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Chiba, Akane, Yoshitaka Uchida, Susanne Kublik, Gisle Vestergaard, Franz Buegger, Michael Schloter und Stefanie Schulz. „Soil Bacterial Diversity Is Positively Correlated with Decomposition Rates during Early Phases of Maize Litter Decomposition“. Microorganisms 9, Nr. 2 (11.02.2021): 357. http://dx.doi.org/10.3390/microorganisms9020357.

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This study aimed to investigate the effects of different levels of soil- and plant-associated bacterial diversity on the rates of litter decomposition, and bacterial community dynamics during its early phases. We performed an incubation experiment where soil bacterial diversity (but not abundance) was manipulated by autoclaving and reinoculation. Natural or autoclaved maize leaves were applied to the soils and incubated for 6 weeks. Bacterial diversity was assessed before and during litter decomposition using 16S rRNA gene metabarcoding. We found a positive correlation between litter decomposition rates and soil bacterial diversity. The soil with the highest bacterial diversity was dominated by oligotrophic bacteria including Acidobacteria, Nitrospiraceae, and Gaiellaceae, and its community composition did not change during the incubation. In the less diverse soils, those taxa were absent but were replaced by copiotrophic bacteria, such as Caulobacteraceae and Beijerinckiaceae, until the end of the incubation period. SourceTracker analysis revealed that litter-associated bacteria, such as Beijerinckiaceae, only became part of the bacterial communities in the less diverse soils. This suggests a pivotal role of oligotrophic bacteria during the early phases of litter decomposition and the predominance of copiotrophic bacteria at low diversity.

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Lamy, D., C. Jeanthon, M. T. Cottrell, D. L. Kirchman, F. Van Wambeke, J. Ras, O. Dahan et al. „Ecology of aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea“. Biogeosciences 8, Nr. 4 (20.04.2011): 973–85. http://dx.doi.org/10.5194/bg-8-973-2011.

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Abstract. Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic prokaryotes able to use both light and organic substrates for energy production. They are widely distributed in coastal and oceanic environments and may contribute significantly to the carbon cycle in the upper ocean. To better understand questions regarding links between the ecology of these photoheterotrophic bacteria and the trophic status of water masses, we examined their horizontal and vertical distribution and the effects of nutrient additions on their growth along an oligotrophic gradient in the Mediterranean Sea. Concentrations of bacteriochlorophyll-a (BChl-a) and AAP bacterial abundance decreased from the western to the eastern basin of the Mediterranean Sea and were linked with concentrations of chlorophyll-a, nutrient and dissolved organic carbon. Inorganic nutrient and glucose additions to surface seawater samples along the oligotrophic gradient revealed that AAP bacteria were nitrogen- and carbon-limited in the ultraoligotrophic eastern basin. The intensity of the AAP bacterial growth response generally differed from that of the total bacterial growth response. BChl-a quota of AAP bacterial communities was significantly higher in the eastern basin than in the western basin, suggesting that reliance on phototrophy varied along the oligotrophic gradient and that nutrient and/or carbon limitation favors BChl-a synthesis.

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Dissertationen zum Thema "Oligotrophic bacteria"

Machelett, Moritz Maximilian. „Nutrient uptake by oceanic oligotrophic bacteria“. Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/418021/.

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The oligotrophic ubiquitous SAR11 clade of alphaproteobacteria and Prochlorococcus cyanobacteria numerically dominate bacterioplankton that drives the ecosystems of the five subtropical oceanic gyres, which cumulatively cover 40% of earth. Common gyre features like extremely low nutrient and chlorophyll concentrations as well as dominance of obligate oligotrophs suggest that the gyre ecosystems are uniform and function at the same pace. Competition in oligotrophic environment should favour optimisation of surface to volume ratio and selection for eÿcient high aÿnity transporters, which could be structurally divergent from known transport systems. To test the hypothesis of gyre ecosystem similarity, SAR11 abundance and metabolic rates (used as a proxy for growth) were compared between three oceanic gyres by assessing their in situ uptake rates of amino acids: leucine and methionine (chapter 3). Bacterial abundance as well as absolute SAR11 amino acid uptake rates were higher in more productive waters of the Equatorial convergence zone of the Atlantic Ocean and SAR11 abundance in the surface mixed layer were similar in the three studied gyres, supporting the similarity hypothesis. However, SAR11 cells took up amino acids 3 – 4 times slower in the South Pacific gyre than in the North and South Atlantic gyres, despite similar concentrations of the amino acids in the gyres. Evidently SAR11 concentration similarity conceals metabolic di˙erences, which should better reflect contrasts in the gyre environments of the two oceans. Thus, the SAR11 metabolic rates indicate that the microbe-driven gyre ecosystem of the South Pacific could function one third slower than the analogous ecosystems of the Atlantic. Being able to dominate bacterioplankton while competing for nutrients at nanomolar concentrations, oligotrophs might possess uniquely eÿcient uptake systems. Identification of porins and high aÿnity ABC transporters in available genomes was guided by bioinform-atical analysis (chapter 4), showing great diversity. Identified porins as well as phosphate-(PstS) and iron-binding proteins (FutA) of Prochlorococcus, which are responsible for the respective transporters aÿnity, were chosen for analysis using X-ray crystallography (chapter 5, 6 and 7). In silico analysis of porin models revealed unique features, which might influence transport function in vivo. High resolution structures of PstS and FutA were determined, enabling a thorough comparison to other substrate-binding proteins such as FutA from Trichodesmium. Interestingly, there is little variation in overall ligand coordination. However, small structural di˙erences might hint at di˙erences in ligand binding. Analysis of the binding site of FutA shows unexpected iron-binding plasticity in the determined crystal structures, which might have implications for iron acquisition in vivo. Employing a combination of UV-Vis spectroscopy and multi-crystal merging techniques made it possible to monitor X-ray induced site specific radiation damage on the iron centre of FutA (chapter 8). The dose of the multi-crystal FutA structure is possibly the lowest reported X-ray dose, to our knowledge, for a crystal structure determined using non-XFEL methods, enabling us to study the iron-binding site mostly una˙ected by radiation damage and X-ray induced artefacts. In conclusion, this work was aimed to unveil unique adaptations of the most abundant organisms on earth. The employed multi-disciplinary approach led to discoveries with implications for diverse ecological and structural investigations.

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Kumar, Arvind. „Studies on oligotrophic bacteria of river Mahananda of northern West Bengal with special emphasis on mics of integrons“. Thesis, University of North Bengal, 2012. http://hdl.handle.net/123456789/1478.

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West, A. J. „Physiology and cell size of oligotrophic and copiotrophic aquatic bacteria“. Thesis, Cardiff University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384161.

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Al-Talhi, Abdullah Dakheel D. „Environmental and medical studies on microbial growth under low nutrient (oligotrophic) conditions“. Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340132.

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Ostrowski, Martin Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. „Physiological adaptation to nutrient limitation in a marine oligotrophic ultramicrobacterium Sphingopyxis alaskensis“. Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/27422.

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Sphingopyxis (formerly Sphingomonas) alaskensis, a numerically abundant species isolated from Alaskan waters and the North Sea represents one of the only pure cultures of a typical oligotrophic ultramicrobacterium isolated from the marine environment. In this study, physiological and molecular characterization of an extinction dilution isolate from the North Pacific indicate that it is a strain of Sphingopyxis alaskenis, extending the known geographical distribution of this strain and affirming its importance as a model marine oligotroph. Given the importance of open ocean systems in climatic processes, it is clearly important to understand the physiology and underlying molecular biology of abundant species, such as S. alaskensis, and to define their role in biogeochemical processes. S. alaskensis is thought to proliferate by growing slowly on limited concentrations of substrates thereby avoiding outright starvation. In order to mimic environmental conditions chemostat culture was used to study the physiology of this model oligotroph in response to slow growth and nutrient limitation. It was found that the extent of nutrient limitation and starvation has fundamentally different consequences for the physiology of oligotrophic ultramicrobacteria compared with well-studied copiotrophic bacteria (Vibrio angustum S14 and Escherichia coli). For example, growth rate played a critical role in hydrogen peroxide resistance of S. alaskensis with slowly growing cells being 10, 000 times more resistant than fast growing cells. In contrast, the responses of V. angustum and E. coli to nutrient availability differed in that starved cells were more resistant than growing cells, regardless of growth rate. In order to examine molecular basis of the response to general nutrient limitation, starvation and oxidative stress in S. alaskensis we used proteomics to define differences in protein profiles of chemostat-grown cultures at various levels of nutrient limitation. High-resolution two-dimensional electrophoresis (2DE) methods were developed and 2DE protein maps were used to define proteins regulated by the level of nutrient limitation. A number of these proteins were identified with the aid of mass spectrometry and cross-species database matching. The identified proteins are involved in fundamental cellular processes including protein synthesis, protein folding, energy generation and electron transport, providing an important step in discovering the molecular basis of oligotrophy in this model organism.

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Matallana, Surget Sabine-Astrid Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. „Physiological and molecular responses of the marine oligotrophic ultramicrobacterium Sphingopyxis Alaskensis rb2256 to visible light and ultraviolet radiation“. Awarded By:University of New South Wales. Biotechnology & Biomolecular Sciences, 2009. http://handle.unsw.edu.au/1959.4/43251.

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Ultraviolet radiation reaching the Earths surface (UVR, 280-400 nm) may penetrate deep into the clear oligotrophic waters influencing a large part of the euphotic layer. Marine heterotrophic bacteria at the surface of the oceans are especially sensitive to the damaging solar radiation due to their haploid genome with little or no functional redundancy and lack of protective pigmentation. In a context of climate change and ozone depletion, it is clearly important to understand the physiology and underlying molecular UVR responses of abundant marine bacteria species. We chose the marine ultramicrobacterium Sphingopyxis alaskensis as a reference species to study the impact of solar radiation due to its numerical abundance in oligotrophic waters and its photoresistance, previously reported. For this purpose, we focused on the formation of the two major UVB-induced DNA photoproducts (CPDs and 6-4PPs) as well as the differential protein expression under solar radiation. We first demonstrated that the GC content of prokaryotic genome had a major effect on the formation of UVB-induced photoproducts, quantified by HPLC-MS/MS. Due to its high GC content, S. alaskensis presented a favoured formation of highly mutagenic cytosine-containing photoproducts and therefore would be more susceptible to UVinduced mutagenesis. By comparing S. alaskensis to another marine bacterium Photobacterium angustum, we observed for the latter strain a remarkable resistance to high UVB doses associated with a decrease in the rate of formation of CPDs explained by a non-conventional activity of photolyase. We also demonstrated that DNA damage in S. alaskensis was markedly modulated by growth temperature and time spent in stationary phase. In order to assess the effects that environmental UV-R had on regulatory networks and pathways of S. alaskensis, and determine how the cells physiology was affected, a quantitative proteomics investigation was performed. Changes in proteome were analyzed, with the recent and powerful mass spectrometry based approach using iTRAQ methodology. Approximately, one third of the proteome of S. alaskensis was identified, with 119 statistically and significantly differentially abundant proteins. Cellular processes, pathways and interaction networks were determined and gave us unique insight into the biology of UV response and adaptation of S. alaskensis.

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Mandal, Amit Kumar. „Exploring physiology of an exopolysaccharide(EPS) producing facultatively oligotrophic bacterium klebsileea pneumoniae pb12 with special emphasis on structure -function analysis of EPS“. Thesis, University of North Bengal, 2015. http://ir.nbu.ac.in/hdl.handle.net/123456789/2755.

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Walters, Evelyn [Verfasser], Harald [Akademischer Betreuer] Horn, Hilde [Akademischer Betreuer] Lemmer und Peter [Akademischer Betreuer] Rutschmann. „Fate and Transport of Fecal Indicator Bacteria in Flume Systems Mimicking an Oligotrophic River / Evelyn Walters. Gutachter: Harald Horn ; Hilde Lemmer ; Peter Rutschmann. Betreuer: Harald Horn“. München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1045730157/34.

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Wenzel, Anja. „The role of terrestrial and phytoplankton-derived organic matter in planktonic food webs“. Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-62287.

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Lakes are important global ecosystems and many of them are nutrient-poor (unproductive). Especially in northern boreal latitudes, lakes may be heavily subsidized by terrestrial organic material (t-OM) from peat layers in the catchment. Thus, in addition to heterotrophic bacteria and phytoplankton, zooplankton may also use the particulate fraction of peat layer t-OM (t-POM) as a potential food source in those systems. Inputs of t-OM in northern latitudes are anticipated to increase in the future due to increasing precipitation and temperature. As t-OM is a good substrate for bacterial growth and as bacteria can often outcompete phytoplankton for inorganic nutrients, the proportions of heterotrophic bacteria and phytoplankton are expected to change in unproductive lakes. This may have pronounced impacts on zooplankton population dynamics. The aim of my thesis was to investigate how changes in food quality and quantity will affect metazoan zooplankton performance in unproductive lakes. Three laboratory studies assessed the quality of specific food components (phytoplankton, bacteria and peat layer t-POM) and their effects on Daphnia survival, growth and reproduction. Further, a mesocosm study with a full natural plankton community tested the predictions of the Light:Nutrient-Hypothesis in an unproductive clear water lake in situ by adding carbon and inorganic nutrients and changing light availability. I found that pure bacterial (Pseudomonas sp.) or t-POM diets could not sustain Daphnia populations, even though both were readily ingested. Daphnids needed at least 10-20% phytoplankton (Rhodomonas) in the diet to survive and even higher proportions (≥ 50%) were necessary for the production of viable offspring. Further, I showed that the dilution of non-limiting concentrations of Rhodomonas with increasing proportions of Pseudomonas or t-POM led to decreased Daphnia performance. Both Pseudomonas and t-POM lack essential biochemicals (fatty acids and sterols). In contrast, mineral nutrient limitation only occurred on t-POM-dominated diets as evidenced by a labeling experiment that showed Daphnia can incorporate carbon and phosphorus from Rhodomonas and Pseudomonas with similar efficiencies. Thus, peat layer t-POM was a lower quality food than Pseudomonas. This was corroborated by the finding that intermediate additions of Pseudomonas to limiting amounts of Rhodomonas supported increased Daphnia survival, growth and reproduction while t-POM additions had no beneficial effect. My results suggest that high terrestrial stable isotope signals in metazoan zooplankton are most likely derived from t-OM that is channeled tohigher trophic levels via the microbial loop (i.e. heterotrophic bacteria and/or bacterivorous protozoa) but not from direct metazoan feeding on t-POM. Furthermore, bacteria may serve as an important supplement to zooplankton diets when phytoplankton abundance is low. However, a sufficient proportion of high quality phytoplankton is always necessary to fulfil mineral and especially biochemical requirements of zooplankton in unproductive aquatic systems. The results of the mesocosm study showed that the Light:Nutrient-Hypothesis is not applicable to unproductive clear water systems in which the phytoplankton community is dominated by mixotrophs. In the face of the theoretical predictions, low light levels led to decreased zooplankton biomass. This was most likely caused by a shift in the algal community composition towards less edible taxa. Another reason may have been a weakening of the microbial loop. This is in line with the results of the laboratory studies that point out the importance of the microbial food web for zooplankton nutrition in unproductive lakes.

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Gammack, Graham F. „Bacterial attachment and activity in oligotrophic environments“. Thesis, Heriot-Watt University, 1988. http://hdl.handle.net/10399/991.

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Bücher zum Thema "Oligotrophic bacteria"

Bacteria in oligotrophic environments: Starvation-survival lifestyle. New York: Chapman & Hall, 1997.

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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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Kirchman, David L. Microbial growth, biomass production, and controls. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0008.

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Soon after the discovery that bacteria are abundant in natural environments, the question arose as to whether or not they were active. Although the plate count method suggested that they were dormant if not dead, other methods indicated that a large fraction of bacteria and fungi are active, as discussed in this chapter. It goes on to discuss fundamental equations for exponential growth and logistic growth, and it describes phases of growth in batch cultures, continuous cultures, and chemostats. In contrast with measuring growth in laboratory cultures, it is difficult to measure in natural environments for complex communities with co-occurring mortality. Among many methods that have been suggested over the years, the most common one for bacteria is the leucine approach, while for fungi it is the acetate-in ergosterol method. These methods indicate that the growth rate of the bulk community is on the order of days for bacteria in their natural environment. It is faster in aquatic habitats than in soils, and bacteria grow faster than fungi in soils. But bulk rates for bacteria appear to be slower than those for phytoplankton. All of these rates for natural communities are much slower than rates measured for most microbes in the laboratory. Rates in subsurface environments hundreds of meters from light-driven primary production and high organic carbon conditions are even lower. Rates vary greatly among microbial taxa, according to data on 16S rRNA. Copiotrophic bacteria grow much faster than oligotrophic bacteria, but may have low growth rates when conditions turn unfavorable. Some of the factors limiting heterotrophic bacteria and fungi include temperature and inorganic nutrients, but the supply of organic compounds is perhaps most important in most environments.

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Buchteile zum Thema "Oligotrophic bacteria"

Overbeck, Jürgen. „Saprophytic and Oligotrophic Bacteria in the Plußsee“. In Ecological Studies, 175–91. New York, NY: Springer New York, 1994. http://dx.doi.org/10.1007/978-1-4612-2606-2_7.

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Hayakawa, Darin H., Megan J. Huggett und Michael S. Rappé. „Ecology and Cultivation of Marine Oligotrophic Bacteria“. In Extremophiles Handbook, 1161–78. Tokyo: Springer Japan, 2011. http://dx.doi.org/10.1007/978-4-431-53898-1_56.

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Zhang, Haihan, und Shilei Zhou. „Screening and Cultivation of Oligotrophic Aerobic Denitrifying Bacteria“. In The Handbook of Environmental Chemistry, 451–73. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-20391-1_13.

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Tan, Tjhing Lok. „Biolog Metabolic Fingerprints for Clustering Marine Oligotrophic Bacteria from Polar Regions“. In Microbial Communities, 161–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60694-6_15.

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Giuliano, L., M. De Domenico und M. M. Yakimov. „Distribution of Representative Oligotrophic Bacteria in a Pelagic Marine Environment (Ligurian Sea) by in situ Hybridization with rRNA-targeted, Fluorescently Labelled Oligonucleotides“. In Mediterranean Ecosystems, 191–95. Milano: Springer Milan, 2001. http://dx.doi.org/10.1007/978-88-470-2105-1_24.

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Mallin, Michael A. „Nutrients and River Ecosystems“. In River Ecology, 25–50. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780199549511.003.0003.

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Abstract Streams and rivers carry nutrients (nitrogen [N] and phosphorus [P]) and transform nutrients, and in turn the nutrients strongly impact the growth and composition of bacteria, phytoplankton, benthic microalgae, macroalgae, and macrophyte vegetation. N exists in organic and inorganic forms and has complex cycles and “spirals” between dissolved inorganic ammonium and nitrate, and labile and refractory organic forms, which also can be dissolved or structurally part of organisms. P is either inorganic or organic, with less complex cycling, but critical as well. Too much N or P (or N and P) causes algal blooms and oxygen demands, and high N inorganic concentrations can be toxic. Sources of nutrients are discussed, as is how and why N or P (or both) can limit (or stimulate) the growth of phytoplankton to bloom conditions. The various concentrations of N and P that characterize eutrophic, mesotrophic, and oligotrophic waters is discussed in regulatory and nonregulatory situations.

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David, Luis, Varinia Lopez-Ramirez, Alejandra Moreno-Letelier, Luis Herrera-Estrella, Valeria Souza und Gabriela Olmedo-Alvarez. „Genomics of Bacteria from an Ancient Marine Origin: Clues to Survival in an Oligotrophic Environment“. In Earth and Environmental Sciences. InTech, 2011. http://dx.doi.org/10.5772/27555.

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Kumar Tiwary, Bipransh, und Nitya Rai. „Oligotrophs: Microbes at Low Nutrient Levels“. In Extremophiles: Diversity, Adaptation and Applications, 333–55. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815080353122010016.

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Extremophiles are microbes capable of adaptation, survival and growth in extreme habitats that are supposed as adverse or lethal for other life forms. Like various other extreme environments, bacteria are also reported to grow in a minimum medium without additional carbon and energy sources. The microorganisms that can grow in low nutrient concentrations, or in the apparent absence of nutrients, are known as oligotrophs. In contrast, copiotroph bacteria grow fast where the resource or nutrient is abundant. Many of these oligotrophs alter their morphology (surface to volume ratio) with changing nutrient concentrations. The diverse oligotrophs have been isolated from the different low-nutrient habitats, such as marine, soil, desert soil, ultra-pure water, etc. The molecular and physiological properties of diverse oligotrophs and their applications in bioremediation are also studied. Oligotrophs would also be suitable for in situ bioremediation, because such microorganisms can grow on the contaminated site without additional nutrients. Remarkably, the adaptive capabilities of oligotrophs convert them into an attractive source for industrial purposes. Thus, oligotrophs have a biotechnological potential, orienting researchers to attempt their isolation and studies from various low-nutrient habitats. The objective of this chapter is to discuss the characteristics, adaptations and applications of oligotrophs.

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Thomson, Peter. „Into the Lake—Deep“. In Sacred Sea. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195170511.003.0012.

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Dress warmly, hold your breath, and take a dive . . . You pierce the surface of Baikal at a soft angle and slip like the low rays of the high-latitude sun into a prism of liquid glass. The water molecules release their bonds with each other to embrace you. Sunlight follows you, wiggles, and scatters; the photons themselves become liquid. Sound becomes a liquid, too, thick and syrupy. Gravity loses its bearings and presses at you from all around. Normal reference points fall away— up and down, left and right—your sense of where you are comes only from subtle changes in light, temperature, and pressure. This will take some getting used to. But not to worry, here in the world’s oldest lake, still in its youth at twenty-five million years, you’ve got nothing but time. And if you put on your special magnifying goggles, you’ll see that you’ve got plenty of company, as well. You’re surrounded by a haze of tiny creatures, each no longer than a millimeter and a half. They’re Epischura baicalensis, those elfin shrimp that float through the lake, sucking massive Baikal through their little digestive tracts, feeding on algae and bacteria, pulling out impurities, and helping to keep the lake clean and clear. Epischura baicalensis are members of a group of organisms known as zooplankton—tiny animals and larva that drift and swim through the water, buffeted about by waves and currents. The miniscule creatures that make up zooplankton live everywhere, in just about every body of water on earth, and like Epischura baicalensis, many of them are little shrimp, or copepods. But Epischura baicalensis live nowhere else, and apparently can’t live anywhere else. It’s said that they can’t live even in a glass of Baikal water removed from the lake. Perhaps they die of homesickness. The water surrounding you as you float in Baikal is about as close as you can get in nature to pure H2O. It’s what aquatic scientists call “oligotrophic”— there’s very little in the way of nutrients and minerals running off into it from the surrounding landscape, and so a very limited supply of some of the basic building blocks of life.

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Nakamura, K., M. Shibata und Y. Miyaji. „SUBSTRATE AFFINITY OF OLIGOTROPHY BACTERIA IN BIOFILM REACTORS“. In Water Pollution Research and Control Brighton, 779–90. Elsevier, 1988. http://dx.doi.org/10.1016/b978-1-4832-8439-2.50079-1.

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Konferenzberichte zum Thema "Oligotrophic bacteria"

Klimenko, N. N. „Estimation of the state of microbocenosis of the peach rhizosphere during the biologization of its cultivation“. In CURRENT STATE, PROBLEMS AND PROSPECTS OF THE DEVELOPMENT OF AGRARIAN SCIENCE. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-2020-5-9-10-113.

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Our research has shown that the use of biologization techniques for growing peaches positively affected the number of bacteria of the main ecological and trophic groups involved in the transformation of soil organic matter: ammonifying bacteria ‒ by 26-47 %; amylolytic bacteria – by 48-103 %; phosphate mobilizing bacteria – by 32-72 %; oligonitrophilic bacteria – by 24-49 %; oligotrophic bacteria – by 57-59 %; cellulolytic bacteria – by 25-39 % in the soil layer of 0-30 and 30-60 cm compared to the control, respectively. There was a decrease in the number of micromycetes, which, in our opinion, is associated with the antagonistic effect of microbial preparations. The use of biologization techniques did not significantly affect the oligotrophy index: its values remained at the control level and fluctuated between 0.6 and 0.8, depending on the experiment variant. The values of the pedotrophy index of the soil of the experimental site on both backgrounds of grassing did not differ and amounted to 1.1 when using Azotobacterin and 1.0 – when bacterizing with CMP. Increasing values of this index indicate the transition of the studied biocenosis to a stable state.

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Radojević, Ivana, Aleksandar Ostojić und Vesna Ranković. „Ecological applications based on bacterial community abundance in reservoirs using an artificial neural network approach“. In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.317r.

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The objective of this study is to analyze the influence and predict abundance the heterotrophic bacteria (psychrophile; mesophile) and facultative oligotrophic bacteria as a reflection of ecological relationships in reservoirs and water quality. We used artificial neural networks (ANNs) to develop models based on input variables derived from two different reservoirs. The neural network models were developed using experimental data which is collected for ten years. Although reservoirs have a different position, different morphometric qualities, trophic state and dominant bacterial community there is a possibility of predicting these bacterial communities with the same input parameters. Comparing the modeled values by ANN with the experimental data indicates that neural network models provide accurate results. The important conclusion of this work is that ANNs can provide a flexible and applicable tool in monitoring water quality across bacterial communities in reservoirs.

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Klimenko, N. N., O. E. Klimenko und L. M. Aleksandrova. „Influence of microbial preparations on the state of plants and microbial cenosis of the rhizosphere of Tulipa L.“ In РАЦИОНАЛЬНОЕ ИСПОЛЬЗОВАНИЕ ПРИРОДНЫХ РЕСУРСОВ В АГРОЦЕНОЗАХ. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-15.05.2020.13.

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Our research has shown that the greatest influence on the height of Tulipa L. plants of the ‘Anna Krasavitsa’ (‘AK’) and ‘Blushing Lady’ (‘BL’) varieties had Aurill and Complex of Microbial Preparations (CMP). The tulip plant height increased by 3-8 % compared to control. The height of the flower glass of ‘AK’ and ‘Holland Chic’ (‘HC’) varieties also increased by 6-7 % compared to control when using microbial preparations (MP). The width of the glass also increased by 4-9 % compared to control. The length of the lower leaf increased by 3-7 % compared to control under the action of Aurill and CMP, respectively. The width of the lower leaf of ‘HC’ increased by 3 % under the action of Aurill compared to the control variant. Depending on the variety and the preparation, the number of ammonifying bacteria increased by 57 % relative to control. The number of amylolytic and phosphate mobilizing bacteria increased on average by 76 % and 63 % under the influence of CMP. The number of oligonitrophilic and oligotrophic bacteria, when using CMP, significantly exceeded the control values: on average, by 60 and 74 %, respectively. The number of micromycetes under the influence of Aurill decreased by 49 % compared to control. The number of cellulolytic bacteria increased by 78 % compared to control mainly because of the introduction of CMP into the tulips rhizosphere. Thus, we found that the bacterization of the rhizosphere of tulips with Aurill and CMP positively affected the morphological characteristics of this flower. Furthermore, these preparations contributed to an increase in the number of agronomically valuable bacteria in the rhizosphere of plants.

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Radojević, Ivana, Nenad Stefanović und Aleksandar Ostojić. „Classification and analysis of key parameters in predicting the state of facultative oligotrophs in two different reservoirs“. In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.312r.

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This study analyzes the condition, influence and dependence of facultative oligotrophs, with different physico-chemical and biological parameters determined in the routine monitoring of the status of natural water quality. The SeLaR database was used for advanced data analysis -statistical methods and data mining. Data were analyzed for reservoirs of different morphometric qualities, different positions, trophic status and dominant bacterial communities, Gruža and Grošnica. Classification and analysis of key influencing factors were applied in this research. The results indicate that the designed data mining system can successfully analyze the condition and impact of facultative oligotrophs in open waters, thus providing new information and knowledge valuable for research investigation and decision making.

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