scholarly journals Weekly variations of viruses and heterotrophic nanoflagellates and their potential impact on bacterioplankton in shallow waters of the central Red Sea

2020 ◽  
Vol 96 (4) ◽  
Author(s):  
Eman I Sabbagh ◽  
Tamara M Huete-Stauffer ◽  
Maria L l Calleja ◽  
Luis Silva ◽  
Miguel Viegas ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Red Sea ◽  
Acid Content ◽  
Temporal Dynamics ◽  
Heterotrophic Bacteria ◽  
Membrane Integrity ◽  
Heterotrophic Nanoflagellates ◽  
Nucleic Acid Content ◽  
Top Down ◽  
The Impact

ABSTRACT Bacterioplankton play a pivotal role in marine ecosystems. However, their temporal dynamics and underlying control mechanisms are poorly understood in tropical regions such as the Red Sea. Here, we assessed the impact of bottom-up (resource availability) and top-down (viruses and heterotrophic nanoflagellates) controls on bacterioplankton abundances by weekly sampling a coastal central Red Sea site in 2017. We monitored microbial abundances by flow cytometry together with a set of environmental variables including temperature, salinity, dissolved organic and inorganic nutrients and chlorophyll a. We distinguished five groups of heterotrophic bacteria depending on their physiological properties relative nucleic acid content, membrane integrity and cell-specific respiratory activity, two groups of Synechococcus cyanobacteria and three groups of viruses. Viruses controlled heterotrophic bacteria for most of the year, as supported by a negative correlation between their respective abundances and a positive one between bacterial mortality rates and mean viral abundances. On the contrary, heterotrophic nanoflagellates abundance covaried with that of heterotrophic bacteria. Heterotrophic nanoflagellates showed preference for larger bacteria from both the high and low nucleic acid content groups. Our results demonstrate that top-down control is fundamental in keeping heterotrophic bacterioplankton abundances low (< 5 × 10 5 cells mL−1) in Red Sea coastal waters.

scholarly journals Effects of oxygen exposure on relative nucleic acid content and membrane integrity in the human gut microbiota

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10602
Author(s):  
Mariia Taguer ◽  
Ophélie Quillier ◽  
Corinne F. Maurice
Keyword(s):  
Nucleic Acid ◽  
Gut Microbiota ◽  
Acid Content ◽  
Membrane Integrity ◽  
Nucleic Acid Content ◽  
Human Gut ◽  
Short Term ◽  
Bacterial Physiology ◽  
Oxygen Exposure ◽  
Anaerobic Chamber

While the diversity of the human gut microbiota is becoming increasingly well characterized, bacterial physiology is still a critical missing link in understanding how the gut microbiota may be implicated in disease. The current best practice for studying bacterial physiology involves the immediate storage of fecal samples in an anaerobic chamber. This reliance on immediate access to anaerobic chambers greatly limits the scope of sample populations that can be studied. Here, we assess the effects of short-term oxygen exposure on gut bacterial physiology and diversity. We use relative nucleic acid content and membrane integrity as markers of bacterial physiology, and 16S rRNA gene amplicon sequencing to measure bacterial diversity. Samples were stored for up to 6 h in either ambient conditions or in anoxic environments created with gas packs or in an anaerobic chamber. Our data indicate that AnaeroGen sachets preserve bacterial membrane integrity and nucleic acid content over the course of 6 h similar to storage in an anaerobic chamber. Short-term oxygen exposure increases bacterial membrane permeability, without exceeding inter-individual differences. As oxygen exposure remains an important experimental consideration for bacterial metabolism, our data suggest that AnaeroGen sachets are a valid alternative limiting loss of membrane integrity for short-term storage of samples from harder-to-access populations.

Variations of the abundance and nucleic acid content of heterotrophic bacteria in Beaufort Shelf waters during winter and spring

2008 ◽  
Vol 74 (3-4) ◽  
pp. 946-956 ◽  
Author(s):  
Claude Belzile ◽  
Sonia Brugel ◽  
Christian Nozais ◽  
Yves Gratton ◽  
Serge Demers
Keyword(s):  
Nucleic Acid ◽  
Acid Content ◽  
Heterotrophic Bacteria ◽  
Nucleic Acid Content

Application of Ogur & Rosen's Method for the Determination of Nucleic Acid Content of Bacteria

1957 ◽  
Vol 12 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Nobuyasu KAWASAKI ◽  
Ichiro TAKI ◽  
Chiaki WATANABE ◽  
Kiyoshi MATOBA ◽  
Mokichiro NISHIO ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Acid Content ◽  
Nucleic Acid Content

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.

Age-Related Effect of Dietary Nucleotides on Liver Nucleic Acid Content in Rats

1997 ◽  
Vol 41 (5) ◽  
pp. 324-330 ◽  
Author(s):  
Ana T. López-Navarro ◽  
Angel Gil ◽  
Antonio Sánchez-Pozo
Keyword(s):  
Nucleic Acid ◽  
Acid Content ◽  
Nucleic Acid Content ◽  
Related Effect ◽  
Age Related ◽  
Dietary Nucleotides

scholarly journals Effect of starvation and refeeding on polyamine concentrations and ornithine decarboxylase antizyme in mammary gland of lactating rats

1983 ◽  
Vol 212 (1) ◽  
pp. 149-153 ◽  
Author(s):  
M E Brosnan ◽  
R Farrell ◽  
H Wilansky ◽  
D H Williamson
Keyword(s):  
Mammary Gland ◽  
Nucleic Acid ◽  
Ornithine Decarboxylase ◽  
Acid Content ◽  
Marked Decrease ◽  
Mammary Glands ◽  
Nucleic Acid Content ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity ◽  
Polyamine Content

Starvation caused a marked increase in putrescine content in mammary gland of lactating rats, together with a marked decrease in activity of ornithine decarboxylase and appearance of measurable ornithine decarboxylase antizyme. 2. Refeeding for 5 h caused disappearance of free antizyme and ornithine decarboxylase activity returned to the value in fed animals. Putrescine concentration remained elevated. 3. There was no significant change in nucleic acid content of mammary gland from starved rats, but spermidine and spermine contents increased significantly. 4. Refeeding for 5 h returned the spermidine content of mammary glands to ‘fed’ values, and significantly decreased the content of spermine, although it did not reach control values. Thus changes in polyamine content of mammary gland in starved rats are clearly dissociated from changes in either RNA content or activities of polyamine-synthetic decarboxylases. 5. Starvation caused a fall in the content of spermidine in liver, with no change in spermine content. Refeeding for 5 h returned the spermidine content to ‘fed’ values.

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