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  • Chemistry
  • Inorganic Chemistry
  • Microorganisms
  • 2015-2019  (3)
  • 1995-1999
  • 1990-1994
  • 1950-1954
  • 1925-1929
  • 2019  (3)
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  • 2015-2019  (3)
  • 1995-1999
  • 1990-1994
  • 1950-1954
  • 1925-1929
Year
  • 1
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    Unknown
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Publication Date: 2022-05-25
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Oceanographic Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2019.
    Description: Marine microbes are key drivers of biogeochemical transformations within the world’s oceans. Although seawater appears uniform at scales that humans often interact with and sample, the world that marine microbes inhabit can be highly heterogeneous, with numerous biological and physical processes giving rise to resource hotspots where nutrient concentrations exceed background levels by orders of magnitude. While the impact of this microscale heterogeneity has been investigated in the laboratory with microbial isolates and theoretical models, microbial ecologists have lacked adequate tools to interrogate microscale processes directly in the natural environment. Within this thesis I introduce three new technologies that enable interrogation of microbial processes at the microscale in natural marine communities. The IFCB-Sorter acquires images and sorts individual phytoplankton cells, directly from seawater, allowing studies exploring connections between the diversity of forms present in the plankton and genetic variability at the single-cell level. The In Situ Chemotaxis Assay (ISCA) is a field-going microfluidic device designed to probe the distribution and role of motility behavior among microbes in aquatic environments. By creating microscale hotspots that simulate naturally occurring ones, the ISCA makes it possible to examine the role of microbial chemotaxis in resource acquisition, phytoplankton-bacteria interactions, and host-symbiont systems. Finally, the Millifluidic In Situ Enrichment (MISE) is an instrument that enables the study of rapid shifts in gene expression that permit microbial communities to exploit chemical hotspots in the ocean. The MISE subjects natural microbial communities to a chemical amendment and preserves their RNA in a minute-scale time series. Leveraging an array of milliliter-volume wells, the MISE allows comparison of community gene expression in response to a chemical stimulus to that of a control, enabling elucidation of the strategies employed by marine microbes to survive and thrive in fluctuating environments. Together, this suite of instruments enables culture-independent examination of microbial life at the microscale and will empower microbial ecologists to develop a more holistic understanding of how interactions at the scale of individual microbes impact processes in marine ecosystems at a global scale.
    Description: I’d like to thank the Gordon and Betty Moore Foundation, the National Science Foundation, and NSERC for funding portions of my research.
    Description: I’d like to thank the Gordon and Betty Moore Foundation, the National Science Foundation, and NSERC for funding portions of my research.
    Keywords: Microorganisms ; Bacteria ; Marine ecology ; Scientific apparatus and instruments ; Plankton ; Plankton--Growth ; Phytoplankton ; Chemical oceanography ; Antarctic Ocean
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
    Location Call Number Expected Availability
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  • 2
    Publication Date: 2021-05-19
    Description: Quantitative and qualitative composition of the bacterioflora of biosediments produced by mussels and oysters were studied in the southern Kerch Strait, area of potential experimental and commercial culture of molluscs. Sampling was made from May to October 1993. A total of 45 various groups of microorganisms were determined and 50 pure bacterial cultures were isolated. On the basis of research into morphological, tinctorial, cultural and physiological and biochemical properties of the isolated strains, they were identified to species or genus level. Of 22 isolated strains of the enteric bacilli group, Escherichia coli accounted for 9.1%, Enterobacter agglomerans, 50%, Citrobacter freundii, 27.3%, C. diversus, 9.1%, C. amalonaticus 4.5%. Among enterococci, mainly Enterococcus faecium were determined, E. faecalis accounting for from 8 to 25% of the enterococci group. Bacteria of the genera Aeromonas, Pseudomonas, Bacillus, Vibrio, and a proteolytic biovariety of enterococcus were most active hydrolase producers. Among aerobic bacteria, Bacillus cereus were identified; anaerobic bacteria were represented mainly by Clostridium perfringens.
    Description: Выявлен обильный рост гетеротрофной (сапрофитной) микрофлоры. Сапрофитные бактерии используют органическое вещество биоотложений в своём конструктивном и энергетическом обмене их количество напрямую связано с наличием легкоусвояемых соединений углерода и азота, поэтому они могут рассматриваться как достаточно информативные биологические индикаторы процессов самоочищения среды. По отдельности определяли количество психрофильных бактерий с температурным оптимумом роста 20-22°С и мезофильных — растущих при температуре инкубации 37°С. Психрофилы в основном состоят из представителей морской флоры, циркулирующих в водной среде и организме гидробионтов. Среди мезофилов доминируют терригенные бактерии, поступающие в прибрежную зону моря с различными источниками антропогенного загрязнения и адаптированные к новым условиям существования. Сезонная динамика этих двух групп сапрофитов в биоотложениях моллюсков района размещения мидий- ных установок представлена на графиках. Общепринятые показатели санитарно-гигиенического и эпидемического состояния объектов внешней среды — бактерии группы кишечных палочек (БГКП) и энтерококки были обнаружены в среднем количестве 240 НВЧ/г. Численность энтерококков в биоотложениях была почти постоянной (за исключением единичного случая), БГКП — более вариабельна. БГКП были представлены в основном цитратассимилируюшими видами. Из 22 выделенных штаммов БГКП Escherichia соli составили 9,1%, Enterobacter agglomerans — 50,0%, Citrobacter freundii — 27,3%, С. diversus — 9,1%, С, amalonaticus — 4,5%. Среди энтерококков определены в основном Enterococcus faecium, а количество Е. faecalis составляло в общей группе энтерококков от 8 до 25%. Таким образом, показатели фекального загрязнения были обнаружены в биоотложениях в невысоких количествах.
    Description: Published
    Keywords: Taxonomy ; Bacterioflora ; Microorganisms ; Biological sedimentation ; Enterobacter agglomerans ; Citrobacter freundii ; Escherichia соli ; Bacillus cereus ; Biotechnologies ; Таксономия ; Микроорганизмы ; Биоотложения ; Анаэробные бактерии ; Энтерококки ; Биотехника
    Repository Name: AquaDocs
    Type: Journal Contribution , Non Refereed
    Format: pp.120-123
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  • 3
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    Unknown
    Universidade Estadual de Maringá. Departamento de Biologia. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais
    Publication Date: 2022-09-07
    Description: Vertebrates and invertebrates are known as important biological vectors in the dispersal of terrestrial neotropical communities (e.g. plants, animals). However, its role in the formation and maintenance of the microbial community in aquatic ecosystems is, in general, greatly underestimated. The objective was to evaluate the relative role of different biological vectors (amphibians and odonates) in the dispersion and consequent structuring of ciliate protozoan communities. An experiment was carried out in the open air, simulated in polyethylene pots, for 33 days, 4 treatments were designated a control with only the action of the wind, without addition of propagules one with addition of propagules from odonatas washes, one with addition of propagules from amphibian washes and one with addition of propagules from washes of both vectors. There were 54 species of ciliates, distributed in 9 orders, being the most representative Hymenostomatida and Peritrichia. The results showed that animal vectors represent an important pathway for the dispersion of ciliates. The species richness and abundance of ciliates showed a significant increase in their values, markedly after the 12th day of experiment. For the species composition, differences were evidenced between the treatments, within each time, as well as between the different treatments throughout the experiment. The dynamics of the dispersion of ciliary protists was enhanced when mediated by biological vectors, especially amphibians. Emphasizing that the nature of the propagule (forms of resistance or active) seems to play a relevant role in the dispersion and colonization capacity, determining the structure and dynamics of the ciliate protist communities.
    Description: Vertebrados e invertebrados são conhecidos como vetores biológicos importantes na dispersão de comunidades neotropicais terrestres (e.g. plantas, animais). Entretanto, seu papel para formação e manutenção da comunidade microbiana em ecossistemas aquáticos é, em geral,subestimado. O objetivo foi avaliar o papel relativo de diferentes vetores biológicos (anfíbios e odonatas) na dispersão e consequente estruturação das comunidades de protozoários ciliados. Foi realizado um experimento ao ar livre, simulados em potes de politileneo, durante 33 dias, foram designados 4 tratamentos um controle com apenas ação do vento, sem adição de propágulos um com adição de propágulos a partir de lavagens de odonatas, um com adição de propágulos a partir de lavagens de anfíbios e um com adição de propágulos a partir de lavagens de ambos os vetores. Foram registradas 54 espécies de ciliados, distribuídos em 9 ordens, sendo as mais representativas Hymenostomatida e Peritrichia. Vetores animais representam uma via importante para a dispersão de ciliados. A riqueza de espécies e abundância de ciliados evidenciaram um aumento significativo em seus valores, marcadamente após o 12º dia de experimento. Para a composição de espécies, diferenças foram evidenciadas entre os tratamentos, dentro de cada tempo e entre os distintos tratamentos ao longo do experimento. A dinâmica da dispersão de protistas ciliados foi potencializada quando mediada por vetores biológicos, especialmente anfíbios. Enfatizando que a natureza do propágulo (formas de resistências ou ativas) parece ter papel relevante na capacidade de dispersão e colonização, determinando a estrutura e dinâmica das comunidades de protistas ciliados.
    Description: Masters
    Keywords: Protistas Ciliophora ; Ciliados planctônicos (Ciliophora) ; Ciliados de água doce ; Colonização ; Sucessão ; Dispersão ; Colonization ; Succession ; Potential dispersal ; Effective dispersal ; Microorganisms ; Passive dispersal ; Ecologia, Comunidades de ; ASFA_2015::P::Protists ; ASFA_2015::F::Freshwater ecology ; ASFA_2015::F::Freshwater organisms ; ASFA_2015::C::Communities (ecological) ; ASFA_2015::P::Plankton ; ASFA_2015::D::Dispersion ; ASFA_2015::C::Colonization
    Repository Name: AquaDocs
    Type: Thesis/Dissertation
    Format: 36pp.
    Location Call Number Expected Availability
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