The influence of bacterial activity and diversity on bacterial growth efficiency was investigated in a flatland river. Eutrophic River Warnow drains predominantly agricultural land and is heavily loaded with nutrients, dissolved and particulate organic matter (DOM and POM), especially humic substances. Although the water column bacterial community consists of many inactive or damaged cells, bacterioplankton sustained a high bacterial secondary production of 0.2-14.5 μg C L(-1) h(-1) and a high DNA synthesis (thymidine uptake) of 6.1-15.5 μg C L(-1) h(-1). The direct and short-term measurement of bacterial respiration (by optodes) revealed high respiration rates especially in summer leading to directly estimated bacterial growth efficiencies (BGE) of 2-28%. These values are compared to calculations based only on bacterial production, which considerably overestimated BGEs. From all these data, River Warnow can be characterized as a strongly remineralizing system. River Warnow was dominated among others by Cytophaga/Flavobacteria and Actinobacteria which are typical for organic rich waters because of their ability to degrade high molecular weight compounds. However, community composition did not significantly affect BGE.
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http://dx.doi.org/10.1007/s00248-010-9729-z | DOI Listing |
Int J Syst Evol Microbiol
January 2025
Department of Life Sciences, University of Coimbra, CEMMPRE, ARISE, Coimbra, Portugal.
Three bacterial strains, designated FZUC8N2.13, FBOR7N2.3 and FZUR7N2.
View Article and Find Full Text PDFExtremophiles
January 2025
Microbiology Laboratory, Department of Botany (DST-FIST and UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal, 731235, India.
To fish-out novel salt-tolerance genes, metagenomic DNA of moderately saline sediments of India's largest hypersaline Sambhar Lake was cloned in fosmid. Two functionally-picked clones helped the Escherichia coli host to tolerate 0.6 M NaCl.
View Article and Find Full Text PDFArch Environ Contam Toxicol
January 2025
Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, Zhejiang, China.
Toxic effects of herbicide atrazine (ATR) have been evaluated in various aquatic organisms, but our understanding of its potential impacts in reptile species remains limited. In this study, the functional performances, and gut microbiota and liver metabolite alterations of ATR-exposed Mauremys sinensis juveniles were measured to evaluate its potential toxic effects in turtles. ATR exposure had no impact on the growth rate, but would allow turtles to right themselves more quickly.
View Article and Find Full Text PDFJ Bacteriol
January 2025
Department of Plant & Microbial Biology, University of California Berkeley, Berkeley, California, USA.
Bacteria encounter chemically similar nutrients in their environment, which impact their growth in distinct ways. Among such nutrients are cobamides, the structurally diverse family of cofactors related to vitamin B (cobalamin), which function as cofactors for diverse metabolic processes. Given that different environments contain varying abundances of different cobamides, bacteria are likely to encounter cobamides that enable them to grow robustly and also those that do not function efficiently for their metabolism.
View Article and Find Full Text PDFJ Bacteriol
January 2025
Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA.
Not only do surface-growing microbes such as biofilms display specific traits compared to planktonic cells, but also they display many heterogeneous behaviors over many spatial and temporal contexts. While the application of molecular genetics tools to extract or visualize gene expression or regulatory function data is now common in studying surface growth, the use of analytical chemistry tools to visualize the spatiotemporal distribution of chemical products synthesized by these surface microbes is less common. Here, we review chemical imaging tools that have been used to inform our understanding of surface-growing microbes.
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