scholarly journals More, smaller bacteria in response to ocean's warming?

2015 ◽  
Vol 282 (1810) ◽  
pp. 20150371 ◽  
Author(s):  
Xosé Anxelu G. Morán ◽  
Laura Alonso-Sáez ◽  
Enrique Nogueira ◽  
Hugh W. Ducklow ◽  
Natalia González ◽  
...  
Keyword(s):  
Heterotrophic Bacteria ◽  
Total Biomass ◽  
Marine Food Webs ◽  
Flow Cytometric ◽  
Short Period ◽  
Major Shift ◽  
Temperature Manipulation ◽  
Atlantic Coastal ◽  
Individual Size ◽  
Interannual Scale

Heterotrophic bacteria play a major role in organic matter cycling in the ocean. Although the high abundances and relatively fast growth rates of coastal surface bacterioplankton make them suitable sentinels of global change, past analyses have largely overlooked this functional group. Here, time series analysis of a decade of monthly observations in temperate Atlantic coastal waters revealed strong seasonal patterns in the abundance, size and biomass of the ubiquitous flow-cytometric groups of low (LNA) and high nucleic acid (HNA) content bacteria. Over this relatively short period, we also found that bacterioplankton cells were significantly smaller, a trend that is consistent with the hypothesized temperature-driven decrease in body size. Although decadal cell shrinking was observed for both groups, it was only LNA cells that were strongly coherent, with ecological theories linking temperature, abundance and individual size on both the seasonal and interannual scale. We explain this finding because, relative to their HNA counterparts, marine LNA bacteria are less diverse, dominated by members of the SAR11 clade. Temperature manipulation experiments in 2012 confirmed a direct effect of warming on bacterial size. Concurrent with rising temperatures in spring, significant decadal trends of increasing standing stocks (3% per year) accompanied by decreasing mean cell size (−1% per year) suggest a major shift in community structure, with a larger contribution of LNA bacteria to total biomass. The increasing prevalence of these typically oligotrophic taxa may severely impact marine food webs and carbon fluxes by an overall decrease in the efficiency of the biological pump.

scholarly journals The significance of biomass allocation to population growth of the invasive species Ambrosia artemisiifolia and Ambrosia trifida with different densities

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenxuan Zhao ◽  
Tong Liu ◽  
Yan Liu ◽  
Hanyue Wang ◽  
Ruili Wang ◽  
...  
Keyword(s):  
Cluster Formation ◽  
Ambrosia Artemisiifolia ◽  
High Density ◽  
High Population ◽  
Leaf Biomass ◽  
Total Biomass ◽  
Low Density ◽  
Population Densities ◽  
Ambrosia Trifida ◽  
Short Period

Abstract Background Ambrosia artemisiifolia and Ambrosia trifida are globally distributed harmful and invasive weeds. High density clusters play an important role in their invasion. For these two species, the early settled populations are distributed at low densities, but they can rapidly achieve high population densities in a short period of time. However, their response to intraspecific competition to improve the fitness for rapid growth and maintenance of high population densities remains unclear. Therefore, to determine how these species form and maintain high population densities, individual biomass allocations patterns between different population densities (low and high), and plasticity during seedling, vegetative, breeding and mature stages were compared. In 2019, we harvested seeds at different population densities and compared them, and in 2020, we compared the number of regenerated plants across the two population densities. Results Most biomass was invested in the stems of both species. Ambrosia trifida had the highest stem biomass distribution, of up to 78%, and the phenotypic plasticity of the stem was the highest. Path analysis demonstrated that at low-density, total biomass was the biggest contributor to seed production, but stem and leaf biomass was the biggest contributors to high-density populations. The number of seeds produced per plant was high in low-density populations, while the seed number per unit area was huge in high-density populations. In the second year, the number of low-density populations increased significantly. A. artemisiifolia and A. trifida accounted for 75.6% and 68.4% of the mature populations, respectively. Conclusions High input to the stem is an important means to regulate the growth of the two species to cope with different densities. These two species can ensure reproductive success and produce appropriate seed numbers. Therefore, they can maintain a stable population over time and quickly form cluster advantages. In the management, early detection of both species and prevention of successful reproduction by chemical and mechanical means are necessary to stop cluster formation and spread.

scholarly journals Flow cytometric analysis of virus-like particles and heterotrophic bacteria within coral-associated reef water

2006 ◽  
Vol 86 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Nicole L. Patten ◽  
Justin R. Seymour ◽  
James G. Mitchell
Keyword(s):  
Flow Cytometry ◽  
Bacterial Community ◽  
Heterotrophic Bacteria ◽  
Flow Cytometric Analysis ◽  
Water Layer ◽  
Dead Coral ◽  
Overlying Water ◽  
Virus Like Particles ◽  
Flow Cytometric ◽  
Diseased Coral

Using flow cytometry, two distinct populations of virus-like particles (VLP) and heterotrophic bacteria were defined within the 12 cm water layer immediately overlying healthy, diseased and dead acroporid corals. Bacterial abundances were similar in overlying water for all coral types, however, VLP were 30% higher above diseased corals than healthy or dead corals. Mean virus to bacteria ratios (VBR) were up to 30% higher above diseased corals than above healthy or dead coral or in distant water. Concomitant with increasing VLP concentrations within 5 cm of coral surfaces, VBR distributions were generally highest above healthy and diseased coral and depressed above dead coral. These results suggest fundamental shifts in the VLP and bacterial community in water associated with diseased corals.

Fungi active in weathering of rock and stone monuments

1995 ◽  
Vol 73 (S1) ◽  
pp. 1384-1390 ◽  
Author(s):  
P. Hirsch ◽  
F. E. W. Eckhardt ◽  
R. J. Palmer Jr.
Keyword(s):  
Electron Microscopy ◽  
Heterotrophic Bacteria ◽  
Close Contact ◽  
Dry Weight ◽  
Cell Counting ◽  
Fungal Colonization ◽  
Total Biomass ◽  
Fungal Cell ◽  
Rock Samples ◽  
Cation Extraction

Fungal colonization of sandstone and granite from Antarctica was studied. Granite from a church, sandstones from a monument and a courthouse in Germany, glazed bricks from a German cathedral, and some other stone types were also examined. All samples contained fungi and heterotrophic bacteria, often also cyanobacteria or algae. For cell counting and enrichment of microorganisms the samples were crushed aseptically, suspended in NaCl–Tween-80, plated on oligotrophic media, and incubated at 16–25 °C dark or in dim light. Total biomass was determined as phospholipid-bound phosphate (PLP). Rock samples were also viewed by electron microscopy. Typical viable fungal cell numbers (CFU∙g−1 dry weight) were the following: sandstone 1.6 × 104, granite 6.2 × 105, and glazed bricks 1.2 × 105. Total biomass ranged from 41 (sandstone) to 137 (glaze) nmol PLP∙g−1 dry weight; antarctic sandstone had 88 nmol PLP∙g−1. Fungal genera identified were the following: Alternaria, Aspergillus, Aureobasidium, Candida, Cladosporium, Paecilomyces, Phoma, Penicillium, and Sporobolomyces. Scanning electron microscopy revealed fungal bridging of open spaces with their hyphae or close contact between fungal hyphae and coccal cells believed to be algae. In some cases fungi were found to produce secondary minerals or their hyphae were covered with partially etched mineral layers. Exopolymer formation was common among the endolithic microorganisms. Mites were found to feed on epiliths. In pure culture, fungi from sandstone produced in 24 h cultures organic acids (citrate, glutamate, pyruvate, malate, succinate, lactate, formate, fumarate, and oxalate). Many of these acids could also be extracted from rock samples. Fungal growth on glucose and mineral powder resulted in up to 60% cation extraction from the mineral. Some fungi were antibiotically active against bacteria or yeasts but also stimulated other bacterial isolates. In summary, epi- and endo-lithic communities contained fungi that probably contribute substantially to the deterioration of many stones and monuments. Key words: rock weathering, biomass, acid excretion, cation extraction.

scholarly journals Spatial distribution of picoseston in the Saratov reservoir in summer

2021 ◽  
pp. 176-190
Author(s):  
E. S. Krasnova ◽  
M. V. Umanskaya
Keyword(s):  
Spatial Distribution ◽  
Food Webs ◽  
Significant Contribution ◽  
Heterotrophic Bacteria ◽  
Total Biomass ◽  
Total Abundance ◽  
Saratov Reservoir ◽  
Autotrophic Picoplankton ◽  
Upper Volga ◽  
Planktonic Food

The structure and spatial distribution of picoseston in the Saratov reservoir in July 2011 and August 2014 are described. On average, the total abundance of cells and particles forming picoseston was 1.87±0.73×106 cells (part.)/mL; and the total biomass of picoseston was 43.8±19.4 µg C/L. During the study period, solitary heterotrophic bacteria and phototrophic picocyanobacteria prevailed in the picoseston of the Saratov reservoir, amounting to 77–100% of its total abundance and biomass. The proportion of picodetrital particles was extremely small (on average, 4.1% of the total biomass of picoseston). The high heterogeneity of picoceston distribution (Cv is 130% and 110% for abundance and biomass, respectively) was found in the Saratov reservoir during the study period. On average, the abundance and biomass of heterotrophic bacterioplaknton and picodetritus at stations of the tributary estuaries were slightly higher than in the riverbed. At the same time, the abundance of picocyanobacteria was higher, and the biomass was lower at the estuarine stations compared to the riverbed ones. The total number of bacterioplankton and autotrophic picoplankton in the Saratov reservoir in 2011 and 2014 corresponded to the mesotrophic level of productivity. Picodetrital particles, in contrast to the Upper Volga and Kama reservoirs, make no significant contribution to the planktonic food webs of the Saratov reservoir, at least during the study period.

scholarly journals Characterization of Thymic Nurse-Cell Lymphocytes, Using an Improved Procedure for Nurse-Cell Isolation

1993 ◽  
Vol 3 (2) ◽  
pp. 103-112 ◽  
Author(s):  
Mireille Lahoud ◽  
David Vremec ◽  
Richard L. Boyd ◽  
Ken Shortman
Keyword(s):  
Nurse Cell ◽  
Flow Cytometric Analysis ◽  
Lymphoid Cells ◽  
Immunomagnetic Bead ◽  
Thymic Nurse Cells ◽  
Flow Cytometric ◽  
Short Period ◽  
High Sedimentation ◽  
Tissue Digestion

Thymic nurse cells (TNC), multicellular complexes consisting of lymphoid cells enclosed within cortical epithelial cells, were isolated from mouse thymus by a modified procedure allowing immunofluorescent labeling and flow cytometric analysis of their lymphoid contents (TNC-L). Collagenase was the only protease used for tissue digestion, to ensure that surface antigen markers remained intact. Zonal unit-gravity elutriation was used to enrich the TNC on the basis of their high sedimentation rate, followed by immunomagnetic bead depletion to remove residual mononuclear cell contaminants and a density separation to remove debris. The TNC-L were then released from inside TNC by a short period of culture. The measured contamination of TNC-L with exogenous thymocytes was around 0.5%. Three-color immunofluorescent labeling revealed that TNC-L included, as well as a maiority of immature CD4+8+3lowthymocytes, about 12% of apparently mature CD4+8-3highand CD4-8+3highthymocytes. TNC are located in the cortex, where mature cells are rare; the occurrence of mature phenotype cells within these structures suggests that they represent a microenvironment for the selection and generation of mature T cells.

scholarly journals Microscale patchiness of virioplankton

2006 ◽  
Vol 86 (3) ◽  
pp. 551-561 ◽  
Author(s):  
J.R. Seymour ◽  
L. Seuront ◽  
M. Doubell ◽  
R.L. Waters ◽  
J.G. Mitchell
Keyword(s):  
Heterotrophic Bacteria ◽  
Open Water ◽  
Sediment Surface ◽  
Viral Abundance ◽  
Normal Distributions ◽  
Flow Cytometric ◽  
Spatiotemporal Scales ◽  
Contrasting Habitats ◽  
Discrete Populations ◽  
Virus Abundance

The microscale spatial distributions of viruses were investigated in three contrasting environments including oligotrophic open ocean, eutrophic coastal and estuarine habitats. The abundances of two discrete populations of both viruses and heterotrophic bacteria were measured at spatial resolutions of between 1 and 5 cm using purpose-designed microscale sampling equipment and flow cytometric sample analysis. Within open water samples, virus distributions were characterized by non-normal distributions and by ‘hotspots’ in abundance where concentrations varied by up to 17-fold. In contrast to patterns generally observed at larger spatiotemporal scales, there was no correlation between bacterial and viral abundance or correspondence between bacteria and virus hotspots within these samples. Consequently, strong hotspots and gradients in the virus:bacteria ratio (VBR) were also apparent within samples. Within vertical profiles taken from above the sediment–water interface within a temperate mangrove estuary, distributions of planktonic viruses were characterized by gradients in abundance, with highest concentrations observed within the 1–2 cm immediately above the sediment surface, and virus distributions were correlated to bacterial abundance (P<0.01). The patterns observed in these contrasting habitats indicate that microscale patchiness of virus abundance may be a common feature of the marine environment. This form of heterogeneity may have important implications for virus–host dynamics and subsequently influence microbial trophodynamics and nutrient cycling in the ocean.

scholarly journals Subculture of Germ Cell-Derived Colonies with GATA4-Positive Feeder Cells from Neonatal Pig Testes

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Kyung Hoon Lee ◽  
Won Young Lee ◽  
Jin Hoi Kim ◽  
Chan Kyu Park ◽  
Jeong Tae Do ◽  
...  
Keyword(s):  
Germ Cell ◽  
Somatic Cells ◽  
Culture Method ◽  
Feeder Cells ◽  
Self Renewal ◽  
Flow Cytometric ◽  
Testicular Cells ◽  
Short Period ◽  
Neonatal Pig

Enrichment of spermatogonial stem cells is important for studying their self-renewal and differentiation. Although germ cell-derived colonies (GDCs) have been successfully cultured from neonatal pig testicular cells under 31°C conditions, the short period ofin vitromaintenance (<2 months) limited their application to further investigations. To develop a culture method that allows forin vitromaintenance of GDCs for long periods, we subcultured the GDCs with freshly prepared somatic cells from neonatal pig testes as feeder cells. The subcultured GDCs were maintained up to passage 13 with the fresh feeder cells (FFCs) and then frozen. Eight months later, the frozen GDCs could again form the colonies on FFCs as shown in passages 1 to 13. Immunocytochemistry data revealed that the FFCs expressed GATA-binding protein 4 (GATA4), which is also detected in the cells of neonatal testes and total testicular cells, and that the expression of GATA4 was decreased in used old feeder cells. The subcultured GDCs in each passage had germ and stem cell characteristics, and flow cytometric analyses revealed that ~60% of these cells were GFRα-1 positive. In conclusion, neonatal pig testes-derived GDCs can be maintained for long periods with GATA4-expressing testicular somatic cells.

scholarly journals Numbers and biomass of soil invertebrates in a reserved field in central Finland

1979 ◽  
Vol 51 (1) ◽  
pp. 172-187 ◽  
Author(s):  
Timo Törmälä
Keyword(s):  
Soil Surface ◽  
Dry Weight ◽  
Soil Invertebrates ◽  
Soil Invertebrate ◽  
Total Biomass ◽  
Invertebrate Community ◽  
Wet Weight ◽  
The Mean ◽  
Individual Size ◽  
Diptera Larvae

The numbers and biomasses of soil invertebrates were investigated in a reserved field in central Finland. Samples were taken monthly from June to September. Five methods were employed to extract the animals from the soil samples. The animals were counted, measured and their dry biomasses were estimated by body length/weight regressions and dry weight/wet weight ratios derived from the literature. In July the total biomass of the soil invertebrate community (excluding Protozoa, Tardigrada and Rotatoria) was about 9.6 g dry weight m-2. The most dominant groups were Lumricidae (73.1 %), Enchytraeidae (5,7 %), Oribatei (5.0 %), and Nematoda (4.4 %). In September the biomass of Diptera larvae was high (1.0 g dw m-2). In numbers nematodes were superior (maximum 12 million m-2) to other groups. Oribatei, Mesostigmata and Collembola were more concentrated to the soil surface than other Acari, Enchytraeidae and Nematoda. The mean individual size decreased with depth in all of the studied groups.

scholarly journals Microbial Diversity of Co-occurring Heterotrophs in Cultures of Marine Picocyanobacteria

2020 ◽  
Author(s):  
Sean Michael Kearney ◽  
Elaina Thomas ◽  
Allison Coe ◽  
Sallie W. Chisholm
Keyword(s):  
Organic Carbon ◽  
Community Composition ◽  
Net Primary Productivity ◽  
Heterotrophic Bacteria ◽  
Global Ocean ◽  
Marine Food Webs ◽  
Enrichment Cultures ◽  
In The Wild ◽  
Family Rhodobacteraceae ◽  
Global Oceans

Abstract BackgroundProchlorococcus and Synechococcus are responsible for around 10% of global net primary productivity, serving as part of the foundation of marine food webs. Heterotrophic bacteria are often co-isolated with these picocyanobacteria in seawater enrichment cultures that contain no added organic carbon; heterotrophs grow on organic carbon supplied by the photolithoautotrophs. We have maintained these cultures of Prochlorococcus and Synechococcus for 100s to 1000s of generations; they represent ideal microcosms for examining the selective pressures shaping autotroph/heterotroph interactions. ResultsWe examine the diversity of heterotrophs in 74 enrichment cultures of these picocyanobacteria obtained from diverse areas of the global oceans. Heterotroph community composition differed between clades and ecotypes of the autotrophic ‘hosts’ but there was significant overlap in heterotroph community composition. Differences were associated with timing, location, depth, and methods of isolation, suggesting the particular conditions surrounding isolation have a persistent effect on long-term culture composition. The majority of heterotrophs in the cultures are rare in the global ocean; enrichment conditions favor the opportunistic outgrowth of these rare bacteria. We did find a few examples, such as heterotrophs in the family Rhodobacteraceae, that are ubiquitous and abundant in cultures and in the global oceans; their abundance in the wild is also positively correlated with that of picocyanobacteria. ConclusionsCollectively, the cultures converged on similar compositions, likely from bottlenecking and selection that happens during the early stages of enrichment for the picocyanobacteria. We highlight the potential for examining ecologically relevant relationships by identifying patterns of distribution of culture-enriched organisms in the global oceans.

scholarly journals Microbial Diversity of Co-occurring Heterotrophs in Cultures of Marine Picocyanobacteria

2020 ◽  
Author(s):  
Sean Michael Kearney ◽  
Elaina Thomas ◽  
Allison Coe ◽  
Sallie W. Chisholm
Keyword(s):  
Organic Carbon ◽  
Community Composition ◽  
Net Primary Productivity ◽  
Heterotrophic Bacteria ◽  
Global Ocean ◽  
Marine Food Webs ◽  
Enrichment Cultures ◽  
In The Wild ◽  
Family Rhodobacteraceae ◽  
Global Oceans

Abstract BackgroundProchlorococcus and Synechococcus are responsible for around 10% of global net primary productivity, serving as part of the foundation of marine food webs. Heterotrophic bacteria are often co-isolated with these picocyanobacteria in seawater enrichment cultures that contain no added organic carbon; heterotrophs grow on organic carbon supplied by the photolithoautotrophs. We have maintained these cultures of Prochlorococcus and Synechococcus for 100s to 1000s of generations; they represent ideal microcosms for examining the selective pressures shaping autotroph/heterotroph interactions. ResultsWe examine the diversity of heterotrophs in 74 enrichment cultures of these picocyanobacteria obtained from diverse areas of the global oceans. Heterotroph community composition differed between clades and ecotypes of the autotrophic ‘hosts’ but there was significant overlap in heterotroph community composition. Differences were associated with timing, location, depth, and methods of isolation, suggesting the particular conditions surrounding isolation have a persistent effect on long-term culture composition. The majority of heterotrophs in the cultures are rare in the global ocean; enrichment conditions favor the opportunistic outgrowth of these rare bacteria. We did find a few examples, such as heterotrophs in the family Rhodobacteraceae, that are ubiquitous and abundant in cultures and in the global oceans; their abundance in the wild is also positively correlated with that of picocyanobacteria. ConclusionsCollectively, the cultures converged on similar compositions, likely from bottlenecking and selection that happens during the early stages of enrichment for the picocyanobacteria. We highlight the potential for examining ecologically relevant relationships by identifying patterns of distribution of culture-enriched organisms in the global oceans.

Sign in / Sign up

Export Citation Format

Share Document