scholarly journals Biochemistry and control of the reductive tricarboxylic acid pathway of CO2 fixation and physiological role of the Rubis CO-like protein

2008 ◽  
Author(s):  
F. Robert Tabita
Keyword(s):  
Physiological Role ◽  
Tricarboxylic Acid ◽  
Acid Pathway ◽  
And Control

scholarly journals l-Aspartate: An Essential Metabolite for Plant Growth and Stress Acclimation

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1887
Author(s):  
Mei Han ◽  
Can Zhang ◽  
Peter Suglo ◽  
Shuyue Sun ◽  
Mingyao Wang ◽  
...  
Keyword(s):  
Plant Growth ◽  
Physiological Role ◽  
Tca Cycle ◽  
Extensive Study ◽  
Cell Compartments ◽  
Stress Acclimation ◽  
Whole Plant ◽  
Glycolysis Pathway ◽  
Acid Pathway

L-aspartate (Asp) serves as a central building block, in addition to being a constituent of proteins, for many metabolic processes in most organisms, such as biosynthesis of other amino acids, nucleotides, nicotinamide adenine dinucleotide (NAD), the tricarboxylic acid (TCA) cycle and glycolysis pathway intermediates, and hormones, which are vital for growth and defense. In animals and humans, lines of data have proved that Asp is indispensable for cell proliferation. However, in plants, despite the extensive study of the Asp family amino acid pathway, little attention has been paid to the function of Asp through the other numerous pathways. This review aims to elucidate the most important aspects of Asp in plants, from biosynthesis to catabolism and the role of Asp and its metabolic derivatives in response to changing environmental conditions. It considers the distribution of Asp in various cell compartments and the change of Asp level, and its significance in the whole plant under various stresses. Moreover, it provides evidence of the interconnection between Asp and phytohormones, which have prominent functions in plant growth, development, and defense. The updated information will help improve our understanding of the physiological role of Asp and Asp-borne metabolic fluxes, supporting the modular operation of these networks.

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 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 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 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.

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.

The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Ions ◽  
Peroxide Bleaching ◽  
Metals Removal ◽  
Peroxide Decomposition ◽  
Equipment Corrosion ◽  
And Performance ◽  
And Control ◽  
Main Effects

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

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