scholarly journals A widely distributed hydrogenase oxidises atmospheric H2 during bacterial growth

2020 ◽  
Author(s):  
Zahra F. Islam ◽  
Caitlin Welsh ◽  
Katherine Bayly ◽  
Rhys Grinter ◽  
Gordon Southam ◽  
...  
Keyword(s):  
Physiological Role ◽  
Pcr Analysis ◽  
Ecological Niches ◽  
Bacterial Phyla ◽  
Oxidation Rates ◽  
Biochemical Assays ◽  
Phylogenomic Analyses ◽  
Phylogenetic Lineages ◽  
And Control

AbstractDiverse aerobic bacteria persist by consuming atmospheric hydrogen (H2) using group 1h [NiFe]-hydrogenases. However, other hydrogenase classes are also distributed in aerobes, including the group 2a [NiFe]-hydrogenase. Based on studies focused on Cyanobacteria, the reported physiological role of the group 2a [NiFe]-hydrogenase is to recycle H2 produced by nitrogenase. However, given this hydrogenase is also present in various heterotrophs and lithoautotrophs lacking nitrogenases, it may play a wider role in bacterial metabolism. Here we investigated the role of this enzyme in three species from different phylogenetic lineages and ecological niches: Acidithiobacillus ferrooxidans (phylum Proteobacteria), Chloroflexus aggregans (phylum Chloroflexota), and Gemmatimonas aurantiaca (phylum Gemmatimonadota). qRT-PCR analysis revealed that the group 2a [NiFe]-hydrogenase of all three species is significantly upregulated during exponential growth compared to stationary phase, in contrast to the profile of the persistence-linked group 1h [NiFe]-hydrogenase. Whole-cell biochemical assays confirmed that all three strains aerobically respire H2 to sub-atmospheric levels, and oxidation rates were much higher during growth. Moreover, the oxidation of H2 supported mixotrophic growth of the carbon-fixing strains C. aggregans and A. ferrooxidans. Finally, we used phylogenomic analyses to show that this hydrogenase is widely distributed and is encoded by 13 bacterial phyla. These findings challenge the current persistence-centric model of the physiological role of atmospheric H2 oxidation and extends this process to two more phyla, Proteobacteria and Gemmatimonadota. In turn, these findings have broader relevance for understanding how bacteria conserve energy in different environments and control the biogeochemical cycling of atmospheric trace gases.

scholarly journals A widely distributed hydrogenase oxidises atmospheric H2 during bacterial growth

2020 ◽  
Vol 14 (11) ◽  
pp. 2649-2658 ◽  
Author(s):  
Zahra F. Islam ◽  
Caitlin Welsh ◽  
Katherine Bayly ◽  
Rhys Grinter ◽  
Gordon Southam ◽  
...  
Keyword(s):  
Physiological Role ◽  
Pcr Analysis ◽  
Ecological Niches ◽  
Bacterial Phyla ◽  
Oxidation Rates ◽  
Biochemical Assays ◽  
Phylogenomic Analyses ◽  
Phylogenetic Lineages ◽  
And Control

Abstract Diverse aerobic bacteria persist by consuming atmospheric hydrogen (H2) using group 1h [NiFe]-hydrogenases. However, other hydrogenase classes are also distributed in aerobes, including the group 2a [NiFe]-hydrogenase. Based on studies focused on Cyanobacteria, the reported physiological role of the group 2a [NiFe]-hydrogenase is to recycle H2 produced by nitrogenase. However, given this hydrogenase is also present in various heterotrophs and lithoautotrophs lacking nitrogenases, it may play a wider role in bacterial metabolism. Here we investigated the role of this enzyme in three species from different phylogenetic lineages and ecological niches: Acidithiobacillus ferrooxidans (phylum Proteobacteria), Chloroflexus aggregans (phylum Chloroflexota), and Gemmatimonas aurantiaca (phylum Gemmatimonadota). qRT-PCR analysis revealed that the group 2a [NiFe]-hydrogenase of all three species is significantly upregulated during exponential growth compared to stationary phase, in contrast to the profile of the persistence-linked group 1h [NiFe]-hydrogenase. Whole-cell biochemical assays confirmed that all three strains aerobically respire H2 to sub-atmospheric levels, and oxidation rates were much higher during growth. Moreover, the oxidation of H2 supported mixotrophic growth of the carbon-fixing strains C. aggregans and A. ferrooxidans. Finally, we used phylogenomic analyses to show that this hydrogenase is widely distributed and is encoded by 13 bacterial phyla. These findings challenge the current persistence-centric model of the physiological role of atmospheric H2 oxidation and extend this process to two more phyla, Proteobacteria and Gemmatimonadota. In turn, these findings have broader relevance for understanding how bacteria conserve energy in different environments and control the biogeochemical cycling of atmospheric trace gases.

scholarly journals Role of ghrelin in fertilization, early embryo development, and implantation periods

Reproduction ◽  
2014 ◽  
Vol 148 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Eugenia Mercedes Luque ◽  
Pedro Javier Torres ◽  
Nicolás de Loredo ◽  
Laura María Vincenti ◽  
Graciela Stutz ◽  
...  
Keyword(s):  
Embryo Development ◽  
Ovulation Induction ◽  
Physiological Role ◽  
Fertilization Rate ◽  
Early Embryo ◽  
Corpora Lutea ◽  
Negative Effects ◽  
Early Embryo Development ◽  
And Control

In order to clarify the physiological role of ghrelin in gestation, we evaluated the effects of administration of exogenous ghrelin (2 or 4 nmol/animal per day) or its antagonist (6 nmol/animal per day of (d-Lys3)GHRP6) on fertilization, early embryo development, and implantation periods in mice. Three experiments were performed, treating female mice with ghrelin or its antagonist: i) starting from 1 week before copulation to 12 h after copulation, mice were killed at day 18 of gestation; ii) since ovulation induction until 80 h later, when we retrieved the embryos from oviducts/uterus, and iii) starting from days 3 to 7 of gestation (peri-implantation), mice were killed at day 18. In experiments 1 and 3, the antagonist and/or the highest dose of ghrelin significantly increased the percentage of atrophied fetuses and that of females exhibiting this finding or a higher amount of corpora lutea compared with fetuses (nCL/nF) (experiment 3: higher nCL/nF-atrophied fetuses: ghrelin 4, 71.4–71.4% and antagonist, 75.0–62.5% vs ghrelin 2, 46.2−15.4% and control, 10–0.0%;n=7–13 females/group;P<0.01). In experiment 2, the antagonist diminished the fertilization rate, and both, ghrelin and the antagonist, delayed embryo development (blastocysts: ghrelin 2, 62.5%; ghrelin 4, 50.6%; and antagonist, 61.0% vs control 78.4%;n=82–102 embryos/treatment;P<0.0001). In experiment 3, additionally, ghrelin (4 nmol/day) and the antagonist significantly diminished the weight gain of fetuses and dams during pregnancy. Our results indicate that not only hyperghrelinemia but also the inhibition of the endogenous ghrelin effects exerts negative effects on the fertilization, implantation, and embryo/fetal development periods, supporting the hypothesis that ghrelin (in ‘adequate’ concentrations) has a physiological role in early gestational events.

scholarly journals Abnormal Cardiac Autonomic Regulation in Mice Lacking ASIC3

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ching-Feng Cheng ◽  
Terry B. J. Kuo ◽  
Wei-Nan Chen ◽  
Chao-Chieh Lin ◽  
Chih-Cheng Chen
Keyword(s):  
Heart Rate ◽  
Autonomic Function ◽  
Physiological Role ◽  
Autonomic Regulation ◽  
Pcr Analysis ◽  
Baseline Heart Rate ◽  
Cardiac Autonomic Function ◽  
Sympathetic Function ◽  
Cardiac Autonomic Regulation

Integration of sympathetic and parasympathetic outflow is essential in maintaining normal cardiac autonomic function. Recent studies demonstrate that acid-sensing ion channel 3 (ASIC3) is a sensitive acid sensor for cardiac ischemia and prolonged mild acidification can open ASIC3 and evoke a sustained inward current that fires action potentials in cardiac sensory neurons. However, the physiological role of ASIC3 in cardiac autonomic regulation is not known. In this study, we elucidate the role of ASIC3 in cardiac autonomic function usingAsic3−/−mice.Asic3−/−mice showed normal baseline heart rate and lower blood pressure as compared with their wild-type littermates. Heart rate variability analyses revealed imbalanced autonomic regulation, with decreased sympathetic function. Furthermore,Asic3−/−mice demonstrated a blunted response to isoproterenol-induced cardiac tachycardia and prolonged duration to recover to baseline heart rate. Moreover, quantitative RT-PCR analysis of gene expression in sensory ganglia and heart revealed that no gene compensation for muscarinic acetylcholines receptors and beta-adrenalin receptors were found inAsic3−/−mice. In summary, we unraveled an important role of ASIC3 in regulating cardiac autonomic function, whereby loss of ASIC3 alters the normal physiological response to ischemic stimuli, which reveals new implications for therapy in autonomic nervous system-related cardiovascular diseases.

Effects of testicular interstitial fluid on the proliferation of the mouse spermatogonial stem cells in vitro

Zygote ◽  
2013 ◽  
Vol 22 (3) ◽  
pp. 395-403 ◽  
Author(s):  
Peng Wang ◽  
Yi Zheng ◽  
Ying Li ◽  
Hua Shang ◽  
Guang-Xuan Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Interstitial Fluid ◽  
Culture Medium ◽  
Physiological Role ◽  
Spermatogonial Stem Cells ◽  
Proliferation Rate ◽  
Pcr Analysis ◽  
Polymerase Chain

SummarySpermatogenesis is a process in adult male mammals supported by spermatogonial stem cells (SSCs). The cultivation of SSCs has potential value, for example for the treatment of male infertility or spermatogonial transplantation. Testicular interstitial fluid was added to culture medium to a final concentration of 5, 10, 20, 30 or 40%, in order to investigate its effects on proliferation of mouse SSCs in vitro, Alkaline phosphatase (AKP) assay, reverse transcription polymerase chain reaction (RT-PCR) analysis and indirect immunofluorescence of cells were performed to identify SSCs, and the proliferation rate and diameters of the SSCs colonies were measured. The results showed that the optimal addition of testicular interstitial fluid to culture medium was 30%. When medium supplemented with 30% testicular interstitial fluid was used to culture mouse SSCs, the optimum proliferation rate and diameter of the cell colonies were 72.53% and 249 μm, respectively, after 8 days in culture, values that were significant higher than those found for other groups (P < 0.05). In conclusion, proliferation of mouse SSCs could be promoted significantly by supplementation of the culture medium with 30% testicular interstitial fluid. More research is needed to evaluate and understand the precise physiological role of testicular interstitial fluid during cultivation of SSCs.

scholarly journals 309 metagenome assembled microbial genomes from deep sediment samples in the Gulfs of Kathiawar Peninsula

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Neelam M. Nathani ◽  
Kaushambee J. Dave ◽  
Priyanka P. Vatsa ◽  
Mayur S. Mahajan ◽  
Parth Sharma ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Anthropogenic Activities ◽  
Ecological Niches ◽  
Microbial Genomes ◽  
Deep Sediment ◽  
Bacterial Phyla ◽  
Metagenomics Data ◽  
Deep Sediments ◽  
Sediment Microbes

AbstractProkaryoplankton genomes from the deep marine sediments are less explored compared to shallow shore sediments. The Gulfs of Kathiawar peninsula experience varied currents and inputs from different on-shore activities. Any perturbations would directly influence the microbiome and their normal homeostasis. Advancements in reconstructing genomes from metagenomes allows us to understand the role of individual unculturable microbes in ecological niches like the Gulf sediments. Here, we report 309 bacterial and archaeal genomes assembled from metagenomics data of deep sediments from sites in the Gulf of Khambhat and Gulf of Kutch as well as a sample from the Arabian Sea. Phylogenomics classified them into 5 archaeal and 18 bacterial phyla. The genomes will facilitate understanding of the physiology, adaptation and impact of on-shore anthropogenic activities on the deep sediment microbes.

scholarly journals Physiological role of the interaction between CARMIL1 and capping protein

2013 ◽  
Vol 24 (19) ◽  
pp. 3047-3055 ◽  
Author(s):  
Marc Edwards ◽  
Yun Liang ◽  
Taekyung Kim ◽  
John A. Cooper
Keyword(s):  
Cell Migration ◽  
Mammalian Cells ◽  
Physiological Role ◽  
Physiological Significance ◽  
Actin Assembly ◽  
Capping Protein ◽  
And Control ◽  
In Cells

The regulation of free barbed ends is central to the control of dynamic actin assembly and actin-based motility in cells. Capping protein (CP) is known to regulate barbed ends and control actin assembly in cells. The CARMIL family of proteins can bind and inhibit CP in vitro, but the physiological significance of the interaction of CARMIL with CP in cells is poorly understood. Mammalian cells lacking CARMIL1 have defects in lamellipodia, macropinocytosis, cell migration, and Rac1 activation. Here we investigate the physiological significance of the CARMIL1–CP interaction, using a point mutant with a well-defined biochemical defect. We find that the CARMIL1–CP interaction is essential for the assembly of lamellipodia, the formation of ruffles, and the process of macropinocytosis. In contrast, the interaction of CARMIL1 with CP shows little to no importance for other functions of CARMIL1, including localization of CARMIL1 to the membrane, activation of Rac1, and cell migration. One implication is that lamellipodia are only marginally important for cell migration in a wound-healing model. The results also suggest that the ability of CARMIL1 to inhibit CP in cells may be regulated.

scholarly journals Effects of ketone bodies on insulin release and islet-cell metabolism in the rat

1983 ◽  
Vol 212 (2) ◽  
pp. 371-377 ◽  
Author(s):  
T J Biden ◽  
K W Taylor
Keyword(s):  
Insulin Secretion ◽  
Insulin Release ◽  
Islet Cell ◽  
Response Curve ◽  
Ketone Bodies ◽  
Cell Metabolism ◽  
Insulin Response ◽  
Physiological Role ◽  
Oxidation Rates

Ketone bodies promote insulin secretion from isolated rat pancreatic islets in the presence of 5 mM-glucose, but are ineffective in its absence. At concentrations of 10 mM or less, the relative abilities of the ketone bodies to potentiate release are in the order D-3-hydroxybutyrate greater than DL-3-hydroxybutyrate greater than acetoacetate. The response curve relating insulin release to D-3-hydroxybutyrate concentration displays a threshold at 1 mM and a maximum at 10 mM. D-3-Hydroxybutyrate (5 mM, but not 10 mM) promotes insulin secretion in the presence of 5 mM concentrations of both L-arginine and DL-glyceraldehyde, but not with L-leucine, L-alanine, L-glutamate or 4-methyl-2-oxopentanoate. The oxidation rates of the exogenous ketone bodies do not correlate well with their capacities to promote insulin release. Moreover, the oxidation of 5 mM-D-3-hydroxybutyrate can be inhibited by 25% with methylmalonate (10 mM) without any diminution of release. The potentiation with D-3-hydroxybutyrate occurs without an observable increase in total islet cyclic AMP. However, a small net efflux matches the relative abilities of the ketone bodies to promote insulin release. With islets from 48 h-starved animals the insulin response is both diminished and less sensitive than in fed animals, since insulin secretion is not significantly raised until a threshold of 5 mM-D-3-hydroxybutyrate is reached. These results suggest that, in the rat at least, there should be a reappraisal of the physiological role of ketone bodies in the promotion of insulin release.

Morphogenesis of a New Human Herpes-Type Virus Isolate (Sasha Virus)

1973 ◽  
Vol 31 ◽  
pp. 592-593
Author(s):  
R. F. Zeigel ◽  
W. Munyon
Keyword(s):  
Virus Isolate ◽  
Calf Serum ◽  
Uranyl Acetate ◽  
Human Herpes ◽  
Human Embryonic Lung ◽  
Human Herpes Virus ◽  
Intracytoplasmic Inclusions ◽  
Hel Cells ◽  
And Control

In continuing studies on the role of viruses in biochemical transformation, Dr. Munyon has succeeded in isolating a highly infectious human herpes virus. Fluids of buccal pustular lesions from Sasha Munyon (10 mo. old) uiere introduced into monolayer sheets of human embryonic lung (HEL) cell cultures propagated in Eagles’ medium containing 5% calf serum. After 18 hours the cells exhibited a dramatic C.P.E. (intranuclear vacuoles, peripheral patching of chromatin, intracytoplasmic inclusions). Control HEL cells failed to reflect similar changes. Infected and control HEL cells were scraped from plastic flasks at 18 hrs. of incubation and centrifuged at 1200 × g for 15 min. Resultant cell packs uiere fixed in Dalton's chrome osmium, and post-fixed in aqueous uranyl acetate. Figure 1 illustrates typical hexagonal herpes-type nucleocapsids within the intranuclear virogenic regions. The nucleocapsids are approximately 100 nm in diameter. Nuclear membrane “translocation” (budding) uias observed.

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