scholarly journals A Novel Algorithm for the Determination of Bacterial Cell Volumes That is Unbiased by Cell Morphology

2011 ◽  
Vol 17 (5) ◽  
pp. 799-809 ◽  
Author(s):  
M. Zeder ◽  
E. Kohler ◽  
L. Zeder ◽  
J. Pernthaler
Keyword(s):  
Bacterial Cell ◽  
Aquatic Ecosystems ◽  
Bacterial Biomass ◽  
Filamentous Bacteria ◽  
Total Abundance ◽  
Binary Images ◽  
Heterotrophic Microbes ◽  
Cell Volumes ◽  
Bacterial Morphotypes

AbstractThe determination of cell volumes and biomass offers a means of comparing the standing stocks of auto- and heterotrophic microbes of vastly different sizes for applications including the assessment of the flux of organic carbon within aquatic ecosystems. Conclusions about the importance of particular genotypes within microbial communities (e.g., of filamentous bacteria) may strongly depend on whether their contribution to total abundance or to biomass is regarded. Fluorescence microscopy and image analysis are suitable tools for determining bacterial biomass that moreover hold the potential to replace labor-intensive manual measurements by fully automated approaches. However, the current approaches to calculate bacterial cell volumes from digital images are intrinsically biased by the models that are used to approximate the morphology of the cells. Therefore, we developed a generic contour based algorithm to reconstruct the volumes of prokaryotic cells from two-dimensional representations (i.e., microscopic images) irrespective of their shape. Geometric models of commonly encountered bacterial morphotypes were used to verify the algorithm and to compare its performance with previously described approaches. The algorithm is embedded in a freely available computer program that is able to process both raw (8-bit grayscale) and thresholded (binary) images in a fully automated manner.

Contribution of large bacteria to bacterial biomass in a deep freshwater lake (Lake Biwa, Japan)

2020 ◽  
Vol 85 ◽  
pp. 131-139
Author(s):  
S Shen ◽  
Y Shimizu
Keyword(s):  
Cell Volume ◽  
Bacterial Cell ◽  
Lake Biwa ◽  
Bacterial Biomass ◽  
Spatial Variations ◽  
Freshwater Lake ◽  
Heterotrophic Nanoflagellates ◽  
Bacterial Productivity ◽  
Transmission Electron ◽  
Seasonal And Spatial Variations

Despite the importance of bacterial cell volume in microbial ecology in aquatic environments, literature regarding the effects of seasonal and spatial variations on bacterial cell volume remains scarce. We used transmission electron microscopy to examine seasonal and spatial variations in bacterial cell size for 18 mo in 2 layers (epilimnion 0.5 m and hypolimnion 60 m) of Lake Biwa, Japan, a large and deep freshwater lake. During the stratified period, we found that the bacterial cell volume in the hypolimnion ranged from 0.017 to 0.12 µm3 (median), whereas that in the epilimnion was less variable (0.016 to 0.033 µm3, median) and much lower than that in the hypolimnion. Additionally, in the hypolimnion, cell volume during the stratified period was greater than that during the mixing period (up to 5.7-fold). These differences in cell volume resulted in comparable bacterial biomass in the hypolimnion and epilimnion, despite the fact that there was lower bacterial abundance in the hypolimnion than in the epilimnion. We also found that the biomass of larger bacteria, which are not likely to be grazed by heterotrophic nanoflagellates, increased in the hypolimnion during the stratified period. Our data suggest that estimation of carbon flux (e.g. bacterial productivity) needs to be interpreted cautiously when cell volume is used as a constant parametric value. In deep freshwater lakes, a difference in cell volume with seasonal and spatial variation may largely affect estimations.

The Calculation of Turbulent Diffusion Coefficients in Aquatic Ecosystems

2019 ◽  
Vol 70 (11) ◽  
pp. 3903-3907
Author(s):  
Galina Marusic ◽  
Valeriu Panaitescu
Keyword(s):  
Transport Equation ◽  
Turbulent Diffusion ◽  
Diffusion Coefficients ◽  
Aquatic Ecosystems ◽  
Specific Area ◽  
Left Bank ◽  
The Right ◽  
Prut River

The paper deals with the issues related to the pollution of aquatic ecosystems. The influence of turbulence on the transport and dispersion of pollutants in the mentioned systems, as well as the calculation of the turbulent diffusion coefficients are studied. A case study on the determination of turbulent diffusion coefficients for some sectors of the Prut River is presented. A new method is proposed for the determination of the turbulent diffusion coefficients in the pollutant transport equation for specific sectors of a river, according to the associated number of P�clet, calculated for each specific area: the left bank, the right bank and the middle of the river.

scholarly journals Cyanobacterial Toxins and Peptides in Lake Vegoritis, Greece

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 394
Author(s):  
Sevasti-Kiriaki Zervou ◽  
Kimon Moschandreou ◽  
Aikaterina Paraskevopoulou ◽  
Christophoros Christophoridis ◽  
Elpida Grigoriadou ◽  
...  
Keyword(s):  
Public Health ◽  
Risk Assessment ◽  
Simultaneous Determination ◽  
Aquatic Ecosystems ◽  
Human Exposure ◽  
Bioactive Metabolites ◽  
Cyanobacterial Toxins ◽  
Major Threat ◽  
Almost All

Cyanotoxins (CTs) produced by cyanobacteria in surface freshwater are a major threat for public health and aquatic ecosystems. Cyanobacteria can also produce a wide variety of other understudied bioactive metabolites such as oligopeptides microginins (MGs), aeruginosins (AERs), aeruginosamides (AEGs) and anabaenopeptins (APs). This study reports on the co-occurrence of CTs and cyanopeptides (CPs) in Lake Vegoritis, Greece and presents their variant-specific profiles obtained during 3-years of monitoring (2018–2020). Fifteen CTs (cylindrospermopsin (CYN), anatoxin (ATX), nodularin (NOD), and 12 microcystins (MCs)) and ten CPs (3 APs, 4 MGs, 2 AERs and aeruginosamide (AEG A)) were targeted using an extended and validated LC-MS/MS protocol for the simultaneous determination of multi-class CTs and CPs. Results showed the presence of MCs (MC-LR, MC-RR, MC-YR, dmMC-LR, dmMC-RR, MC-HtyR, and MC-HilR) and CYN at concentrations of <1 μg/L, with MC-LR (79%) and CYN (71%) being the most frequently occurring. Anabaenopeptins B (AP B) and F (AP F) were detected in almost all samples and microginin T1 (MG T1) was the most abundant CP, reaching 47.0 μg/L. This is the first report of the co-occurrence of CTs and CPs in Lake Vegoritis, which is used for irrigation, fishing and recreational activities. The findings support the need for further investigations of the occurrence of CTs and the less studied cyanobacterial metabolites in lakes, to promote risk assessment with relevance to human exposure.

scholarly journals Development of biosensor for the determination of total viable bacterial cell count.

1991 ◽  
Vol 57 (2) ◽  
pp. 281-285 ◽  
Author(s):  
Masakazu Hoshi ◽  
Hideaki Nishi ◽  
Tetsuhito Hayashi ◽  
Masayo Okuzumi ◽  
Etsuo Watanabe
Keyword(s):  
Cell Count ◽  
Bacterial Cell ◽  
Viable Bacterial Cell

Validation of an analytical method for the quantitative determination of selenium in bacterial biomass by ultraviolet–visible spectrophotometry

2018 ◽  
Vol 255 ◽  
pp. 182-186 ◽  
Author(s):  
Ana Paula Mörschbächer ◽  
Anja Dullius ◽  
Carlos Henrique Dullius ◽  
Cassiano Ricardo Bandt ◽  
Daniel Kuhn ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Analytical Method ◽  
Bacterial Biomass ◽  
Visible Spectrophotometry

Anomalously low electrostatic bending stiffness of graphene oxide 2D membranes regulates its environmental fate in aquatic ecosystems

2021 ◽  
Author(s):  
Mohamad Ali Sanjari Shahrezaei ◽  
Seyed Mohammad-Reza Taheri ◽  
Hesam Nikfazan ◽  
Alexandra Satalov ◽  
Mohsen Moazzami Gudarzi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Environmental Impact ◽  
Surface Waters ◽  
Aquatic Ecosystems ◽  
Environmental Fate ◽  
2D Materials ◽  
Bending Stiffness ◽  
High Importance

Though deemed to be of high importance for the determination of environmental impact of 2D materials upon their release into surface waters, control over the conformational engineering of atomically thin...

Spectrophotometric and visual determination of zoledronic acid by using a bacterial cell-derived nanopaper doped with curcumin

2019 ◽  
Vol 186 (11) ◽  
Author(s):  
Shadab Faham ◽  
Raouf Ghavami ◽  
Hamed Golmohammadi ◽  
Gholamreza Khayatian
Keyword(s):  
Zoledronic Acid ◽  
Bacterial Cell

scholarly journals Frequency of mentum deformity in Chironomus sancticaroli (Diptera: Chironomidae) in a laboratory culture

2019 ◽  
Vol 14 (2) ◽  
pp. 1
Author(s):  
Mariana Silveira Guerra Moura e Silva ◽  
Ana Lúcia Silva Marigo ◽  
William Viveiros ◽  
Mônica Luisa Kuhlmann
Keyword(s):  
Aquatic Ecosystems ◽  
Low Frequency ◽  
Average Frequency ◽  
Laboratory Culture ◽  
Inorganic Pollutants ◽  
Ecotoxicological Tests ◽  
Research And Teaching ◽  
Dilution Water

The midge Chironomus sancticaroli (Diptera: Chironomidae) has been used in ecotoxicological tests because it is sensitive to a variety of inorganic pollutants. Among the parameters used to evaluate the toxicity of a substance is the frequency of mentum deformity, which is part of the oral system of this organism. However, there is still no consensus on the baseline level (percentage) of acceptable deformities in laboratory cultures not exposed to pollutants. The determination of this variable is important to ensure the validity of bioassays and to compare cultures from different research and teaching institutions. Once this value is established, it will also be used to monitor the quality of organisms cultured, since factors such as inbreeding could increase the frequency of mentum deformity. Thus, the objective of this study was to quantify the percentage of mentum deformity in the fourth instar of C. sancticaroli larvae from the culture of the Laboratory of Aquatic Ecosystems, at Embrapa Meio Ambiente. The average frequency of mentum deformity obtained was 6,63%. It is believed that factors such as the renewal of the culture with the inclusion of spawns from the laboratories of other institutions, as well as the control of the quality of the dilution water and the sediment of the breeding may have contributed to a low frequency of mentum deformity of the culture observed in this study.

scholarly journals New Mixed Y0.5R0.5VO4 and RVO4:Bi Materials: Synthesis, Crystal Structure and Some Luminescence Properties

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 94 ◽  
Author(s):  
Leonid Vasylechko ◽  
Andrii Tupys ◽  
Vasyl Hreb ◽  
Volodymyr Tsiumra ◽  
Iryna Lutsiuk ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Binary Systems ◽  
Materials Synthesis ◽  
Lattice Constants ◽  
Cation Radius ◽  
Photoluminescence Studies ◽  
The Impact ◽  
Structure And Microstructure ◽  
Cell Volumes

The results are reported on a precise crystal structure and microstructure determination of new mixed YVO4-based orthovanadates of Y0.5R0.5VO4 (R = Sm, Tb, Dy, Ho, Tm, Yb, Lu) as well as some Bi3+-doped RVO4 (R = La, Gd, Y, Lu) nano- (submicro-) materials. The formation of continuous solid solutions in the YVO4–RVO4 pseudo-binary systems (R = Sm, Tb, Dy, Ho, Tm, Yb, Lu) has been proved. The lattice constants and unit cell volumes of the new mixed orthovanadates were analyzed as a function of R3+ cation radius. The impact of crystal structure parameters on the energy band gap of the materials was studied by means of photoluminescence studies of the Bi3+-doped compounds.

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