scholarly journals Viral Production in Seawater Filtered Through 0.2-μm Pore-Size Filters: A Hidden Biogeochemical Cycle in a Neglected Realm

2021 ◽  
Vol 12 ◽  
Author(s):  
Yanhui Yang ◽  
Toshi Nagata
Keyword(s):  
Pore Size ◽  
Nucleic Acid Content ◽  
Bacterial Cells ◽  
Viral Production ◽  
Viral Lysis ◽  
Viral Abundance ◽  
Marine Food Webs ◽  
Through Flow ◽  
Reduction Assay ◽  
Pass Through

Viral production is a key parameter for assessing virus-mediated biogeochemical cycles. One widely used method for the determination of viral production, called the virus reduction assay, reduces viral abundance, while maintaining bacterial abundance, using 0.2-μm pore-size filters. Viral production is estimated from the increase of viral abundance during incubation. We hypothesized that small-cell-sized bacterial communities can pass through 0.2-μm filters and drive viral production, representing a missing fraction of viral production that is missed by the virus reduction assay. Coastal seawater was filtered through 0.2-μm filters and diluted with virus-free seawater. Viral production in the <0.2-μm filtrate was estimated from changes in viral abundance determined through flow cytometry. We found that viruses were produced in the <0.2-μm communities, which were strongly enriched with low nucleic acid content bacteria. Estimated viral production in the <0.2-μm filtrates accounted for up to 43% of total viral production and 10% of dissolved organic carbon production mediated by viral lysis of bacterial cells. By not considering viral production in these <0.2-μm communities, the virus reduction assay may underestimate viral production. Virus–bacteria interactions in <0.2-μm communities may represent a significant and overlooked role of viruses in marine food webs and carbon fluxes.

scholarly journals Using flow cytometry and light-induced fluorescence technique to characterizethe variability and characteristics of bioaerosols in springtime at Metro Atlanta, Georgia

2018 ◽  
Author(s):  
Arnaldo Negron ◽  
Natasha DeLeon-Rodriguez ◽  
Samantha M. Waters ◽  
Luke D. Ziemba ◽  
Bruce Anderson ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Nucleic Acid ◽  
Acid Content ◽  
Fungal Spores ◽  
Epifluorescence Microscopy ◽  
Nucleic Acid Content ◽  
Rain Event ◽  
Bacterial Cells ◽  
Sampling System ◽  
Spores And Pollen

Abstract. The abundance and speciation of primary biological aerosol particles (PBAP) is important for understanding their impacts on human health, cloud formation and ecosystems. Towards this, we have developed a protocol for quantifying PBAP collected from large volumes of air with a portable wet-walled cyclone bioaerosol sampler. A flow cytometry (FCM) protocol was then developed to quantify and characterize the PBAP populations from the sampler, which were confirmed against epifluorescence microscopy. The sampling system and FCM analysis were used to study PBAP in Atlanta, GA over a two-month period and showed clearly defined populations of DNA-containing particles: Low Nucleic Acid-content particles (bioLNA), High Nucleic Acid-content particles (HNA) being fungal spores and pollen. We find that daily-average springtime PBAP concentration (1 to 5 μm diameter) ranged between 1.4 × 104 and 1.1 × 105 m−3. The BioLNA population dominated PBAP during dry days (72 ± 18 %); HNA dominated the PBAP during humid days and following rain events, where HNA (e.g., wet-ejected fungal spores) comprised up to 92 % of the PBAP number. Concurrent measurements with a Wideband Integrated Bioaerosol Sensor (WIBS-4A) showed that FBAP and total FCM counts are similar; HNA (from FCM) significantly correlated with ABC type FBAP concentrations throughout the sampling period (and for the same particle size range, 1–5 μm diameter). However, the FCM bioLNA population, possibly containing bacterial cells, did not correlate to any FBAP type. The lack of correlation of any WIBS FBAP type with the bioLNA suggest bacterial cells may be more difficult to detect with autofluorescence than previously thought. Ιdentification of bacterial cells even in the FCM (bioLNA population) is challenging, given that the fluorescence level of stained cells at times may be comparable to that seen from abiotic particles. HNA and ABC displayed highest concentration on a humid and warm day after a rain event (4/14), suggesting that both populations correspond to wet-ejected fungal spores. Overall, information from both instruments combined reveals a highly dynamic airborne bioaerosol community over Atlanta, with a considerable presence of fungal spores during humid days, and a bioLNA population dominating bioaerosol community during dry days.

scholarly journals THE INFLUENCE OF ELECTROMAGNETIC FIELD ON MORPHOPHYSIOLOGICAL PARAMETERS OF BACTERIAL CELLS EVALUATED THROUGH FLOW CYTOMETRY

2016 ◽  
Author(s):  
Elena Radu ◽  
◽  
F. Marinescu ◽  
I. Savin ◽  
C. M. Kamerzan (Saviuc) ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Electromagnetic Field ◽  
Bacterial Cells ◽  
Through Flow

scholarly journals The Exact Groundwater Divide on Water Table between Two Rivers: A Fundamental Model Investigation

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 685 ◽  
Author(s):  
Peng-Fei Han ◽  
Xu-Sheng Wang ◽  
Li Wan ◽  
Xiao-Wei Jiang ◽  
Fu-Sheng Hu
Keyword(s):  
Water Level ◽  
Water Table ◽  
Catchment Area ◽  
River Basins ◽  
Two Dimensional ◽  
Local Flow ◽  
Fundamental Model ◽  
Through Flow ◽  
Flow Systems ◽  
Pass Through

The groundwater divide within a plane has long been delineated as a water table ridge composed of the local top points of a water table. This definition has not been examined well for river basins. We developed a fundamental model of a two-dimensional unsaturated–saturated flow in a profile between two rivers. The exact groundwater divide can be identified from the boundary between two local flow systems and compared with the top of a water table. It is closer to the river of a higher water level than the top of a water table. The catchment area would be overestimated (up to ~50%) for a high river and underestimated (up to ~15%) for a low river by using the top of the water table. Furthermore, a pass-through flow from one river to another would be developed below two local flow systems when the groundwater divide is significantly close to a high river.

scholarly journals Diel Variation of Viral Production in a Coastal Subtropical Marine System

Diversity ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 426
Author(s):  
Pei-Chi Ho ◽  
Gwo-Ching Gong ◽  
Chih-Hao Hsieh ◽  
Patrichka Wei-Yi Chen ◽  
An-Yi Tsai
Keyword(s):  
Linear Regression ◽  
Coastal Region ◽  
Cell Types ◽  
Linear Regression Method ◽  
Diel Variation ◽  
Viral Production ◽  
Viral Lysis ◽  
Bacterial Mortality ◽  
Marine System ◽  
Classical Linear Regression

Viral production (VP) and bacterial mortality by viral lysis critically influence the production and mortality of aquatic bacteria. Although bacterial production, mortality by viral lysis, and viral density have been found to exhibit diel variations, the diel change in viral production has rarely been investigated. In this study, we conducted two diel dilution incubation experiments in a semi-enclosed, nutrient-rich coastal region in northeastern Taiwan to estimate the diel viral production and the mortality by viral lysis. We also compared two methods (linear regression between viral density and time versus arithmetic mean of VP during incubation) of estimating viral production. We found that viral production estimated by linear regression and bacterial mortality by viral lysis were higher during the daytime than during the nighttime. A possible explanation for the high viral production at daytime is that the bacterial community was composed of cell types with higher burst sizes at daytime. We further argued that the classical linear regression method can be used only when viral density significantly linearly increases with time, which does not always occur in dilution incubations. This study offered observations of diel variation in viral dynamics and discussed the methods estimating viral production in a marine environment.

scholarly journals Lytic viral infection of bacterioplankton in deep waters of the western Pacific Ocean

2013 ◽  
Vol 10 (12) ◽  
pp. 19633-19659
Author(s):  
Y. Li ◽  
T. Luo ◽  
J. Sun ◽  
L. Cai ◽  
N. Jiao ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Biogeochemical Cycling ◽  
Lytic Infection ◽  
Western Pacific ◽  
Viral Population ◽  
Western Pacific Ocean ◽  
Viral Lysis ◽  
Viral Abundance ◽  
Host Mortality ◽  
The Western Pacific

Abstract. As the most abundant biological entities in the ocean, viruses can influence host mortality and nutrients recycling mainly through lytic infection. Yet ecological characteristics of virioplankton and viral impacts on host mortality and biogeochemical cycling in the deep sea are largely unknown. In present study, viral abundance and lytic infection was investigated throughout the water column in the western Pacific Ocean. Both the prokaryotic and viral abundance and production showed a significantly decreasing trend from epipelagic to meso- and bathypelagic waters. Viral abundance decreased from 0.36–1.05 × 1010 particles L−1 to 0.43–0.80 × 109 particles L−1, while the virus : prokaryote ratio varied from 7.21–16.23 to 2.45–23.40, at surface and 2000 m depth, respectively. The lytic viral production rates in surface and 2000 m waters were, averagely, 1.03 × 1010 L−1 day−1 and 5.74 × 108 L−1 day−1, respectively. Relatively high percentages of prokaryotic cells lysed by virus in 1000 m and 2000 m were observed, suggesting a significant contribution of viruses to prokaryotic mortality in deep ocean. The carbon released by viral lysis in deep western Pacific Ocean waters was from 0.03 to 2.32 μg C L−1 day−1. Our findings demonstrated a highly dynamic and active viral population in the deep western Pacific Ocean and suggested that virioplankton play an important role in the microbial loop and subsequently biogeochemical cycling in deep oceans.

scholarly journals Picoplankton Distribution and Activity in the Deep Waters of the Southern Adriatic Sea

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1655 ◽  
Author(s):  
Danijela Šantić ◽  
Vedrana Kovačević ◽  
Manuel Bensi ◽  
Michele Giani ◽  
Ana Vrdoljak Tomaš ◽  
...  
Keyword(s):  
Deep Sea ◽  
Large Scale ◽  
Heterotrophic Bacteria ◽  
Eastern Mediterranean ◽  
Environmental Parameters ◽  
Anoxygenic Phototrophic Bacteria ◽  
Heterotrophic Nanoflagellates ◽  
Nucleic Acid Content ◽  
Viral Lysis ◽  
Deep Waters

Southern Adriatic (Eastern Mediterranean Sea) is a region strongly dominated by large-scale oceanographic processes and local open-ocean dense water formation. In this study, picoplankton biomass, distribution, and activity were examined during two oceanographic cruises and analyzed in relation to environmental parameters and hydrographic conditions comparing pre and post-winter phases (December 2015, April 2016). Picoplankton density with the domination of autotrophic biomasses was higher in the pre-winter phase when significant amounts of picoaoutotrophs were also found in the meso-and bathy-pelagic layers, while Synechococcus dominated the picoautotrophic group. Higher values of bacterial production and domination of High Nucleic Acid content bacteria (HNA bacteria) were found in deep waters, especially during the post-winter phase, suggesting that bacteria can have an active role in the deep-sea environment. Aerobic anoxygenic phototrophic bacteria accounted for a small proportion of total heterotrophic bacteria but contributed up to 4% of bacterial carbon content. Changes in the picoplankton community were mainly driven by nutrient availability, heterotrophic nanoflagellates abundance, and water mass movements and mixing. Our results suggest that autotrophic and heterotrophic members of the picoplankton community are an important carbon source in the food web in the deep-sea, as well as in the epipelagic layer. Besides, viral lysis may affect the activity of the picoplankton community and enrich the water column with dissolved organic carbon.

scholarly journals Using flow cytometry and light-induced fluorescence to characterize the variability and characteristics of bioaerosols in springtime in Metro Atlanta, Georgia

2020 ◽  
Vol 20 (3) ◽  
pp. 1817-1838 ◽  
Author(s):  
Arnaldo Negron ◽  
Natasha DeLeon-Rodriguez ◽  
Samantha M. Waters ◽  
Luke D. Ziemba ◽  
Bruce Anderson ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Nucleic Acid ◽  
Acid Content ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Epifluorescence Microscopy ◽  
Nucleic Acid Content ◽  
Rain Event ◽  
Bacterial Cells ◽  
Biological Aerosol Particles

Abstract. The abundance and speciation of primary biological aerosol particles (PBAP) is important for understanding their impacts on human health, cloud formation, and ecosystems. Towards this, we have developed a protocol for quantifying PBAP collected from large volumes of air with a portable wet-walled cyclone bioaerosol sampler. A flow cytometry (FCM) protocol was then developed to quantify and characterize the PBAP populations from the sampler, which were confirmed against epifluorescence microscopy. The sampling system and FCM analysis were used to study PBAP in Atlanta, GA, over a 2-month period and showed clearly defined populations of nucleic-acid-containing particles: low nucleic acid-content particles above threshold (LNA-AT) and high nucleic acid-content particles (HNA) likely containing wet-ejected fungal spores and pollen. We find that the daily-average springtime PBAP concentration (1 to 5 µm diameter) ranged between 1.4×104 and 1.1×105 m−3. The LNA-AT population dominated PBAP during dry days (72±18 %); HNA dominated the PBAP during humid days and following rain events, where HNA comprised up to 92 % of the PBAP number. Concurrent measurements with a Wideband Integrated Bioaerosol Sensor (WIBS-4A) showed that fluorescent biological aerosol particles (FBAP) and total FCM counts are similar; HNA (from FCM) moderately correlated with ABC-type FBAP concentrations throughout the sampling period (and for the same particle size range, 1–5 µm diameter). However, the FCM LNA-AT population, possibly containing bacterial cells, did not correlate with any FBAP type. The lack of correlation of any WIBS FBAP type with the LNA-AT suggests that airborne bacterial cells may be more difficult to unambiguously detect with autofluorescence than currently thought. Identification of bacterial cells even in the FCM (LNA-AT population) is challenging, given that the fluorescence level of stained cells at times may be comparable to that seen from abiotic particles. HNA and ABC displayed the highest concentration on a humid and warm day after a rain event (14 April 2015), suggesting that both populations correspond to wet-ejected fungal spores. Overall, information from both instruments combined reveals a highly dynamic airborne bioaerosol community over Atlanta, with a considerable presence of fungal spores during humid days and an LNA-AT population dominating the bioaerosol community during dry days.

scholarly journals Encapsulation of Micro- and Milli-Sized Particles with a Hollow-Type Spherical Bacterial Cellulose Gel via Particle-Preloaded Droplet Cultivation

2019 ◽  
Vol 20 (19) ◽  
pp. 4919 ◽  
Author(s):  
Toru Hoshi ◽  
Masashige Suzuki ◽  
Mayu Ishikawa ◽  
Masahito Endo ◽  
Takao Aoyagi
Keyword(s):  
Pore Size ◽  
Cell Suspension ◽  
Bacterial Cellulose ◽  
Silicone Oil ◽  
Drug Carrier ◽  
Immobilized Enzymes ◽  
Bioactive Molecules ◽  
Interior Space ◽  
Alginate Gel ◽  
Pass Through

A hollow-type spherical bacterial cellulose (HSBC) gel prepared using conventional methods cannot load particles larger than the pore size of the cellulose nanofiber network of bacterial cellulose (BC) gelatinous membranes. In this study, we prepared a HSBC gel encapsulating target substances larger than the pore size of the BC gelatinous membranes using two encapsulating methods. The first method involved producing the BC gelatinous membrane on the surface of the core that was a spherical alginate gel with a diameter of 2 to 3 mm containing the target substances. With this method, the BC gelatinous membrane was biosynthesized using Gluconacetobacter xylinus at the interface between the cell suspension attached onto the alginate gel and the silicone oil. The second method involved producing the BC gel membrane on the interface between the silicone oil and cell suspension, as well as the spherical alginate gel with a diameter of about 1 mm containing target substances. After the BC gelatinous membrane was biosynthesized, an alginate gel was dissolved in a phosphate buffer to prepare an HSBC gel with the target substances. These encapsulated substances could neither pass through the BC gelatinous membrane of the HSBC gel nor leak from the interior space of the HSBC gel. These results suggest that the HSBC gel had a molecular sieving function. The HSBC gel walls prepared using these methods were observed to be uniform and would be useful for encapsulating bioactive molecules, such as immobilized enzymes in HSBC gel, which is expected to be used as a drug carrier.

An atomically thin molecular aperture: two-dimensional gallium phosphate

2019 ◽  
Vol 4 (3) ◽  
pp. 667-673 ◽  
Author(s):  
Gregory S. Hutchings ◽  
Eric I. Altman
Keyword(s):  
Pore Size ◽  
Building Blocks ◽  
Two Dimensional ◽  
Pass Through ◽  
Gallium Phosphate

Stretching two-dimensional GaPO4 causes its GaO4 and PO4 building blocks to counter-rotate allowing its pore size to be dynamically tuned to allow specific molecules to pass through.

scholarly journals Does the High Nucleic Acid Content of Individual Bacterial Cells Allow Us To Discriminate between Active Cells and Inactive Cells in Aquatic Systems?

2001 ◽  
Vol 67 (4) ◽  
pp. 1775-1782 ◽  
Author(s):  
Philippe Lebaron ◽  
Pierre Servais ◽  
Helene Agogué ◽  
Claude Courties ◽  
Fabien Joux
Keyword(s):  
Flow Cytometry ◽  
Nucleic Acid ◽  
Acid Content ◽  
Fluorescent Dyes ◽  
Specific Activity ◽  
Aquatic Systems ◽  
Nucleic Acid Content ◽  
Leucine Incorporation ◽  
Bacterial Cells ◽  
Syto 13

ABSTRACT The nucleic acid contents of individual bacterial cells as determined with three different nucleic acid-specific fluorescent dyes (SYBR I, SYBR II, and SYTO 13) and flow cytometry were compared for different seawater samples. Similar fluorescence patterns were observed, and bacteria with high apparent nucleic acid contents (HNA) could be discriminated from bacteria with low nucleic acid contents (LNA). The best discrimination between HNA and LNA cells was found when cells were stained with SYBR II. Bacteria in different water samples collected from seven freshwater, brackish water, and seawater ecosystems were prelabeled with tritiated leucine and then stained with SYBR II. After labeling and staining, HNA, LNA, and total cells were sorted by flow cytometry, and the specific activity of each cellular category was determined from leucine incorporation rates. The HNA cells were responsible for most of the total bacterial production, and the specific activities of cells in the HNA population varied between samples by a factor of seven. We suggest that nucleic acid content alone can be a better indicator of the fraction of growing cells than total counts and that this approach should be combined with other fluorescent physiological probes to improve detection of the most active cells in aquatic systems.

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