scholarly journals Effect of P depletion on the functional pools of diatom carbohydrates, and their utilization by bacterial communities

2020 ◽  
Vol 641 ◽  
pp. 49-62
Author(s):  
C Labry ◽  
D Delmas ◽  
B Moriceau ◽  
M Gallinari ◽  
J Quere ◽  
...  
Keyword(s):  
Heterotrophic Bacteria ◽  
Chemical Characterization ◽  
Bacterial Degradation ◽  
Tight Coupling ◽  
P Limitation ◽  
Polymer Hydrolysis ◽  
Attached Bacteria ◽  
Particle Potential ◽  
Bay Of Brest ◽  
P Depletion

Phosphorus (P) limitation of phytoplankton growth is known to affect the accumulation and release of carbohydrates (CHO) by micro-algae. However, relatively little is known about the fate of algal exudates, notably their bacterial degradation. The CHO chemical characterization is also not exhaustive, especially in ‘functional’ pools relevant for phytoplankton physiology (particulate reserve [R] or structural [S] CHO) and for bacterial degradation (dissolved mono- [MDCHO] and polysaccharides [P-DCHO]). In this study, we investigated how P depletion and repletion affect the CHO composition in diatom Thalassiosira weissflogii cultures, and the shortterm response of free and diatom-attached bacteria in terms of abundance and potential βglucosidase activity (βGlc). The bacterial inoculum was composed of the bacterial consortiums of diatom precultures and a natural bacterial community from the Bay of Brest. P depletion favored CHO accumulation in diatom cells, mainly as R i.e. soluble CHO accumulated in cytoplasm, but also as S, polysaccharides linked to the cell wall. The R:S ratio was high in the present diatom cultures. The high M-DCHO observed in P-deplete cultures (twice that of P-replete cultures) when P-DCHO remained quite similar is explained both by active polysaccharide hydrolysis (very high potential βGlc of attached bacteria) and reduced uptake of M-DCHO by Pdepleted bacteria. P depletion of heterotrophic bacteria favors labile CHO accumulation, which may affect particle potential aggregation. However, the remarkably constant M-DCHO concentration over time for both conditions suggests tight coupling between phytoplankton accumulation, release, polymer hydrolysis and monomer uptake by bacteria.

Abundance and chemical characterization of extracellular carbohydrates released by the marine diatomCylindrotheca fusiformisunder N- and P-limitation

2004 ◽  
Vol 39 (2) ◽  
pp. 133-142 ◽  
Author(s):  
Erika Magaletti ◽  
Ranieri Urbani ◽  
Paola Sist ◽  
Carla Rita Ferrari ◽  
Anna Maria Cicero
Keyword(s):  
Chemical Characterization ◽  
P Limitation

scholarly journals Diel Protein Regulation of Marine Picoplanktonic Communities Assessed by Metaproteomics

2021 ◽  
Vol 9 (12) ◽  
pp. 2621
Author(s):  
Augustin Géron ◽  
Johannes Werner ◽  
Philippe Lebaron ◽  
Ruddy Wattiez ◽  
Sabine Matallana-Surget
Keyword(s):  
Heterotrophic Bacteria ◽  
Temporal Structure ◽  
Sea Surface ◽  
Diel Cycle ◽  
Diel Variation ◽  
Protein Regulation ◽  
Free Living ◽  
Bacterial Populations ◽  
Form Complex ◽  
Attached Bacteria

The diel cycle is of enormous biological importance in that it imposes temporal structure on ecosystem productivity. In the world’s oceans, microorganisms form complex communities that carry out about half of photosynthesis and the bulk of life-sustaining nutrient cycling. How the functioning of microbial communities is impacted by day and night periods in surface seawater remains to be elucidated. In this study, we compared the day and night metaproteomes of the free-living and the particle-attached bacterial fractions from picoplanktonic communities sampled from the northwest Mediterranean Sea surface. Our results showed similar taxonomic distribution of free-living and particle-attached bacterial populations, with Alphaproteobacteria, Gammaproteobacteria and Cyanobacteria being the most active members. Comparison of the day and night metaproteomes revealed that free-living and particle-attached bacteria were more active during the day and the night, respectively. Interestingly, protein diel variations were observed in the photoautotroph Synechococcales and in (photo)-heterotrophic bacteria such as Flavobacteriales, Pelagibacterales and Rhodobacterales. Moreover, our data demonstrated that diel cycle impacts light-dependent processes such as photosynthesis and UV-stress response in Synechococcales and Rhodobacterales, respectively, while the protein regulation from the ubiquitous Pelagibacterales remained stable over time. This study unravels, for the first time, the diel variation in the protein expression of major free-living and particle-attached microbial players at the sea surface, totaling an analysis of eight metaproteomes.

scholarly journals Dynamics of various viral groups infecting autotrophic plankton in Lake Geneva

2012 ◽  
Vol 3 (2) ◽  
pp. 171 ◽  
Author(s):  
Ammini Parvathi ◽  
Xu Zhong ◽  
Stéphan Jacquet
Keyword(s):  
Carbon Fixation ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Heterotrophic Bacteria ◽  
Significant Proportion ◽  
Late Summer ◽  
Lake Geneva ◽  
Tight Coupling ◽  
Virus Like Particles ◽  
Signature Genes ◽  
Gradient Gel Electrophoresis

Viral community structure and dynamics were investigated for the first time in surface waters (0–20 m) of Lake Geneva over a 5-month period between July and November 2011. Abundances of autotrophic picoplankton, heterotrophic bacteria and virus-like particles determined using flow cytometry revealed their predominance during the summer months followed by a slight decrease in fall. Two groups of viruses could be discriminated, referred to as virus-like particles (VLP) group 1 and 2. The abundance of VLP1 correlated significantly with the bacterial abundance, while that of VLP2 correlated with both chlorophyll a and picocyanobacterial abundance suggesting a tight coupling between these viral groups and bacteria or phytoplankton. The abundance of cyanomyoviruses and cyanopodoviruses varied between 7.3 × 102 ml−1 (July) to 1.2 × 104 ml−1 (November) and 5.8 × 103 ml−1 (July) to 2.2 × 104 ml−1 (September), respectively. The abundance of the picocyanobacterial hosts was in concurrence with that of the cyanophages, being higher in late summer. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) of viral signature genes such as g20, g23, mcp, polB, psbA and psbD revealed a relatively high richness within these genes with their diversity increasing towards the summer months. The diversity of psbD was found to be particularly high and correlated with picocyanobacterial abundance suggesting that cyanophages may be directly responsible for a significant proportion of carbon fixation in Lake Geneva.

Correlation between specific groups of heterotrophic bacteria and microcystin biodegradation in freshwater bodies of central Europe

2019 ◽  
Vol 95 (11) ◽  
Author(s):  
Dariusz Dziga ◽  
Mikołaj Kokociński ◽  
Jakub Barylski ◽  
Grzegorz Nowicki ◽  
Anna Maksylewicz ◽  
...  
Keyword(s):  
Bacterial Community Structure ◽  
Redundancy Analysis ◽  
Heterotrophic Bacteria ◽  
Comprehensive Analysis ◽  
Bacterial Degradation ◽  
Physical Parameters ◽  
Natural Ecosystems ◽  
Biodegradation Process ◽  
Freshwater Bodies ◽  
Bacterial Groups

ABSTRACT Microcystins produced by several toxic cyanobacterial strains constitute an important problem for public health. Bacterial degradation of these hepatotoxins may play an important role in natural ecosystems, however the nature of the process is very poorly understood. The aim of our study was to investigate the possible interactions between cyanotoxin producers and degraders. Samples collected from 24 water bodies in western Poland were analysed to determine the chemo-physical parameters, phytoplankton content, bacterial community structure and microcystin-biodegradation potency. A redundancy analysis identified a positive correlation between the capacity of a community to degrade microcystin LR (MC-LR) and temperature, pH, chlorophyll a concentration and the abundance of MC-producers. The relative abundance of classes F38, TM7-3 and the order WCHB1-81c (Actinobacteria) was significantly higher in the lakes with MC-biodegradation potency. Some specific bacterial genera belonging to Acidobacteria, Chloroflexi, Gemmatimonadetes, Firmicutes and TM7 were closely correlated with the occurrence of Microcystis spp. Furthermore, the MC biodegradation process was connected with the same bacterial groups. Thus, our approach allowed us to provide a broader picture of some specific relations between microcystin producers and potential microcystin degraders. A more comprehensive analysis of the existing correlations may be helpful in our understanding of natural mechanisms of MC elimination using bacteria such as MC-degraders.

Distribution of heterotrophic bacteria in relation to the concentration of particulate organic matter in seawater

1983 ◽  
Vol 29 (5) ◽  
pp. 570-575 ◽  
Author(s):  
Kimio Fukami ◽  
Usio Simidu ◽  
Nobuo Taga
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Heterotrophic Bacteria ◽  
Viable Count ◽  
Plate Count ◽  
Free Living ◽  
Count Method ◽  
Attached Bacteria ◽  
Geographical Scale ◽  
Living Bacteria

The relationship between the number of bacteria and the concentration of particulate organic carbon (POC) in seawater was investigated. In coastal seawater in summer, the POC concentration showed better correlation to the density of bacteria obtained by the viable plate count method (viable count, V.C.) than by the total direct count method (total count, T.C.). The number of attached bacteria (A) showed significant fluctuation, both laterally on a geographical scale and vertically in the water column; on the other hand, the number of free-living bacteria (F) was relatively constant. The POC concentration had a much higher correlation with A (r = 0.8795) than with T.C. (r = 0.7339), and had a low correlation with F (r = 0.6935). Moreover, a very good correlation was observed between the density of bacteria obtained by V.C. and A (r = 0.9153). These results indicate that when the concentration of particulate organic matter (POM) increases, some free-living bacteria become attached to POM, and grow on the surface of POM. These communities of attached bacteria have the ability to make colonies on plate media and can be counted as the "viable plate count."

Research of Effect on Water Quality of Combined Stainless Steel Plastic Pipe and PPR Pipe

2013 ◽  
Vol 864-867 ◽  
pp. 2108-2111
Author(s):  
Tao Wu ◽  
Zeng Zhang Wang
Keyword(s):  
Water Quality ◽  
Stainless Steel ◽  
Drinking Water ◽  
Water Distribution ◽  
Heterotrophic Bacteria ◽  
Plate Count ◽  
Plastic Pipe ◽  
Attached Bacteria ◽  
Drinking Water Distribution

Taking combined stainless steel plastic pipe and PPR pipe which was widely used in the secondary water supply system as research objects, we do a research of effect on water quality of these pipelines. These test indexes were divided into basic indexes and additional indexes. In addition, heterotrophic bacteria plate count was used to observe the attached bacteria on the inner wall of these two different pipes. The results showed that these two kinds of pipes are qualified for their hygienic safety as drinking water distribution equipments. The effects of pipe wall on water quality increased with the immersion time. Combined stainless steel plastic pipe is better than PPR pipe for less impact on water quality, less biofilm microbes attached, better stability, superior antibacterial effects. The combined stainless steel plastic pipe can give a better hygienic safety protection for drinking water.

The impacts of cyanobacteria on pulp-and-paper wastewater toxicity and biodegradation of wastewater contaminants

2005 ◽  
Vol 51 (7) ◽  
pp. 531-540 ◽  
Author(s):  
A E Kirkwood ◽  
C Nalewajko ◽  
R R Fulthorpe
Keyword(s):  
Waste Treatment ◽  
Heterotrophic Bacteria ◽  
Pulp And Paper ◽  
Bacterial Degradation ◽  
Nutrient Concentrations ◽  
Nutrient Competition ◽  
Batch Studies ◽  
Paper Waste ◽  
Paper Wastewater ◽  
Cyanobacterial Biomass

This study investigated the effects of cyanobacteria from pulp-and-paper waste-treatment systems on biological toxicity removal and biodegradation of certain wastewater contaminants. In field and batch studies, using the Microtox®assay, cyanobacterial biomass and final wastewater toxicity were significantly correlated. In softwood-based wastewater, a decrease in toxicity was negatively correlated with cyanobacterial biomass, but the correlation was positive in hardwood-based wastewater. In the softwood-based wastewater, toxicity remained higher in the light than it was in the dark, whereas in hardwood-based wastewater, toxicity was lower in the light than it was in the dark. All of these results were light-dependent, suggesting that the photosynthetic growth of cyanobacteria is required to induce significant effects. When grown in mixed cultures with bacterial degraders, cyanobacteria from pulp-and-paper waste-treatment systems generally impeded the biodegradation of the wastewater contaminants phenol and dichloroacetate (DCA). However, there was one case where the cyanobacterium Phormidium insigne improved the bacterial degradation of DCA. Doubling inorganic nutrient concentrations did not improve phenol or DCA biodegradation in the majority of cases, indicating that nutrient competition is not a major factor. These data suggest that cyanobacteria play an important role during the biological treatment of contaminants, and, hence, toxicity removal in pulp-and-paper waste-treatment systems.Key words: cyanobacteria, heterotrophic bacteria, biodegradation, pulp and paper waste-treatment, wastewater toxicity.

scholarly journals Acidification increases microbial polysaccharide degradation in the ocean

2009 ◽  
Vol 6 (6) ◽  
pp. 11377-11400 ◽  
Author(s):  
J. Piontek ◽  
M. Lunau ◽  
N. Händel ◽  
C. Borchard ◽  
M. Wurst ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Extracellular Enzymes ◽  
Heterotrophic Bacteria ◽  
Co2 Storage ◽  
Experimental Simulation ◽  
Bacterial Degradation ◽  
Seawater Ph ◽  
Carbon Pump ◽  
Acidic Sugars ◽  
Carbon Dioxide Co2

Abstract. With the accumulation of anthropogenic carbon dioxide (CO2), a proceeding decline in seawater pH has been induced that is referred to as ocean acidification. The ocean's capacity for CO2 storage is strongly affected by biological processes, whose feedback potential is difficult to evaluate. The main source of CO2 in the ocean is the decomposition and subsequent respiration of organic molecules by heterotrophic bacteria. However, very little is known about potential effects of ocean acidification on bacterial degradation activity. This study reveals that the degradation of polysaccharides, a major component of marine organic matter, by bacterial extracellular enzymes was significantly accelerated during experimental simulation of ocean acidification. Results were obtained from pH perturbation experiments, where rates of extracellular α- and β-glucosidase were measured and the loss of neutral and acidic sugars from phytoplankton-derived polysaccharides was determined. Our study suggests that a faster bacterial turnover of polysaccharides at lowered ocean pH has the potential to affect the cycling of organic carbon in the future ocean by weakening the biological carbon pump and increasing the respiratory production of CO2.

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