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Articles 1 - 7 of 7
Full-Text Articles in Life Sciences
Occurrence And Distribution Of Diverse Populations Of Magnetic Protists In A Chemically Stratified Coastal Salt Pond, Dennis A. Bazylinski, David R. Schlezinger, Brian H. Howes, Richard B. Frankel, Slava S. Epstein
Occurrence And Distribution Of Diverse Populations Of Magnetic Protists In A Chemically Stratified Coastal Salt Pond, Dennis A. Bazylinski, David R. Schlezinger, Brian H. Howes, Richard B. Frankel, Slava S. Epstein
Slava Epstein
Chemical stratification occurs in the water columns and sediments of many aquatic habitats resulting in vertical chemical and redox gradients. Various types of microorganisms are often associated with specific depths and chemical parameters in these situations. For example, magnetite-producing magnetotactic bacteria are known to form horizontal "plates" of cells at the oxic/anoxic transition zone (OATZ) of such environments. Here, we report the presence of populations of diverse magnetic protists in a seasonally chemically stratified, coastal salt pond. The protistan types included several biflagellates, a dinoflagellate, and a ciliate that were each associated with specific depths and thus, specific chemical, microbiological …
Enumeration Of Sandy Sediment Bacteria: Search For Optimal Protocol, Slava Epstein, Jeffrey Rossel
Enumeration Of Sandy Sediment Bacteria: Search For Optimal Protocol, Slava Epstein, Jeffrey Rossel
Slava Epstein
We examined and compared a variety of existing protocols for enumeration of bacteria from marine sandy sediments. The focus was on how to dislodge bacteria from sediment particles; a commercial blender, an ultrasonic cleaner, and an ultrasonic cell disrupter were tested. The ultrasonic cell disrupter was found to be the most efficient device for bacterial dislodgment. With a 5 mm microtip vibrating at 109 μm amplitude and 20 kHz, the optimal sonication time of small (≤ 0.5 cm³) samples was 180 s. Having identified the optimal dislodgment treatment, we went through other steps of sediment bacteria enumeration (use of surfactants, …
Environmental Rrna Inventories Miss Over Half Of Protistan Diversity, Sunok Jeon, John Bunge, Chesley Leslin, Thorsten Stoeck, Sunhee Hong, Slava S. Epstein
Environmental Rrna Inventories Miss Over Half Of Protistan Diversity, Sunok Jeon, John Bunge, Chesley Leslin, Thorsten Stoeck, Sunhee Hong, Slava S. Epstein
Slava Epstein
Background The main tool to discover novel microbial eukaryotes is the rRNA approach. This approach has important biases, including PCR discrimination against certain rRNA gene species, which makes molecular inventories skewed relative to the source communities. The degree of this bias has not been quantified, and it remains unclear whether species missed from clone libraries could be recovered by increasing sequencing efforts, or whether they cannot be detected in principle. Here we attempt to discriminate between these possibilities by statistically analysing four protistan inventories obtained using different general eukaryotic PCR primers. Results We show that each PCR primer set-specific clone …
Enumeration Of Sandy Sediment Bacteria: Are The Counts Quantitative Or Relative?, Slava S. Epstein, D. Alexander, K. Cosman, A. Dompé, S. Gallagher, J. Jarsobski, E. Laning, R. Martinez, G. Panasik, C. Peluso, R. Runde, E. Timmer
Enumeration Of Sandy Sediment Bacteria: Are The Counts Quantitative Or Relative?, Slava S. Epstein, D. Alexander, K. Cosman, A. Dompé, S. Gallagher, J. Jarsobski, E. Laning, R. Martinez, G. Panasik, C. Peluso, R. Runde, E. Timmer
Slava Epstein
Several tests were carried out to enable evaluation of the precision with which sandy sediment bacteria could be enumerated. This represented the first attempt to place direct epifluorescence counts of benthic bacteria on a quantitative, rather than relative, ground. The tests combined in situ radioisotope ([³H], [¹⁴C]) labeling of sediment bacteria, bacterial dislodgment by ultrasonic treatment, and bacterial enumeration via fluorescent staining. The results provided direct and indirect evidence that the employed protocol for bacterial enumeration accounted for 88 to 98% of all bacteria present in sediments. The identified approach thus allowed for a rather complete quantification of sediment bacteria. …
Methodology Of In Situ Grazing Experiments: Evaluation Of A New Vital Dye For Preparation Of Fluorescently Labeled Bacteria, Slava S. Epstein, Jeffrey Rossel
Methodology Of In Situ Grazing Experiments: Evaluation Of A New Vital Dye For Preparation Of Fluorescently Labeled Bacteria, Slava S. Epstein, Jeffrey Rossel
Slava Epstein
A new fluorescent dye, cyanoditolyl tetrazolium chloride (CTC), is suggested for use in grazing studies to prepare fluorescently labeled bacteria (FLB). As food tracers, CTC-stained bacteria appeared to have advantages over FLBs prepared in accordance with previously published protocols. The CTC is a vital dye, non-toxic to the examined bacteria; in our study, the CTC-stained bacteria grew at the same rate as non-stained bacteria. This is an advantage over the commonly used DTAF-employing staining protocol, which results in heat-killed or immobilized prey particles. The CTC-stained bacteria were not toxic to the studied bacterial grazers; a test ciliate grew on FLBs …
New Cultivation Strategies Bring More Microbial Plankton Species Into The Laboratory, Stephen J. Giovannoni, Rachel A. Foster, Michael S. Rappé, Slava S. Epstein
New Cultivation Strategies Bring More Microbial Plankton Species Into The Laboratory, Stephen J. Giovannoni, Rachel A. Foster, Michael S. Rappé, Slava S. Epstein
Slava Epstein
No abstract provided.
Protistan Diversity In The Arctic: A Case Of Paleoclimate Shaping Modern Biodiversity?, Thorsten Stoeck, Jennifer Kasper, John Bunge, Chesley Leslin, Valya Ilyin, Slava S. Epstein
Protistan Diversity In The Arctic: A Case Of Paleoclimate Shaping Modern Biodiversity?, Thorsten Stoeck, Jennifer Kasper, John Bunge, Chesley Leslin, Valya Ilyin, Slava S. Epstein
Slava Epstein
Background The impact of climate on biodiversity is indisputable. Climate changes over geological time must have significantly influenced the evolution of biodiversity, ultimately leading to its present pattern. Here we consider the paleoclimate data record, inferring that present-day hot and cold environments should contain, respectively, the largest and the smallest diversity of ancestral lineages of microbial eukaryotes. Methodology/Principal Findings We investigate this hypothesis by analyzing an original dataset of 18S rRNA gene sequences from Western Greenland in the Arctic, and data from the existing literature on 18S rRNA gene diversity in hydrothermal vent, temperate sediments, and anoxic water column communities. …