scholarly journals Factors controlling aminoacyl-transfer-ribonucleic acid synthesis in vitro by a plant system

1971 ◽  
Vol 121 (3) ◽  
pp. 495-501 ◽  
Author(s):  
K. L. Tao ◽  
T. C. Hall
Keyword(s):  
Protein Synthesis ◽  
Acid Synthesis ◽  
Regulatory Function ◽  
Factors Affecting ◽  
Trna Species ◽  
Aminoacyl Transfer ◽  
Leaf System ◽  
Bean Leaves

1. Factors affecting aminoacyl-tRNA synthesis in vitro by cell-free preparations from bean leaves were investigated. 2. Evidence was obtained that optimum concentrations as well as correct ratios of Mg2+ and ATP are required for aminoacyl-tRNA synthesis in the bean-leaf system. 3. The results indicated that pH is a controlling factor having differential effects on the formation of individual aminoacyl-tRNA species. The possible micro-regulatory function of pH in protein synthesis in vivo is discussed with special reference to alanyl-tRNA formation. 4. Very low rates of alanine-stimulated pyrophosphate exchange were observed in the absence of tRNA. This observation is discussed relative to proposals about the mechanism of aminoacyl-tRNA synthesis.

scholarly journals Rates of aminoacyl-transfer-ribonucleic acid synthesis in vivo and in vitro by bean leaves

1970 ◽  
Vol 117 (5) ◽  
pp. 853-859 ◽  
Author(s):  
T. C. Hall ◽  
K. L. Tao
Keyword(s):  
Amino Acids ◽  
Ribonucleic Acid ◽  
Acid Synthesis ◽  
Leaf Discs ◽  
Endogenous Amino Acids ◽  
Intact Leaves ◽  
Aminoacyl Transfer ◽  
Bean Leaves

1. A procedure for measuring rates of aminoacyl-tRNA synthesis in vitro and in intact leaves is presented. 2. Leaf discs showed rates close to those of intact leaves. 3. Cell-free preparations showed similar rates when assayed by pyrophosphate exchange, but actual aminoacyl-tRNA formation rates appeared to be much lower. Evidence is presented that dilution of supplied labelled amino acids was a major factor causing the low apparent rates. 4. Attempts to strip endogenous amino acids from plant tRNA resulted in low acceptor capability of the tRNA.

scholarly journals Biochemical studies with a new cytotoxic immunosuppressive agent, 3-acetyl-5-(4-fluorobenzylidene)-2,5-dihydro-4-hydroxy-2-oxothiophen (I.C.I. 47776)

1967 ◽  
Vol 102 (3) ◽  
pp. 705-711 ◽  
Author(s):  
T. J. Franklin ◽  
B. Higginson
Keyword(s):  
Protein Synthesis ◽  
Lymph Node ◽  
Nucleic Acid ◽  
Acid Synthesis ◽  
Nucleic Acid Synthesis ◽  
Atp Concentration ◽  
Inhibition Of Protein Synthesis ◽  
Lymph Node Cells

1. A new cytotoxic agent, 3-acetyl-5-(4-fluorobenzylidene)-2,5-dihydro-4-hydroxy-2-oxothiophen (I.C.I. 47776), strongly inhibits protein and nucleic acid synthesis and, to a smaller extent, respiration in lymph-node cells and Landschütz ascites-tumour cells in vitro. 2. The activity of I.C.I. 47776 in vitro declines as the pH of the medium is increased and is inversely proportional to the concentration of serum in the medium. 3. The compound has no effect on the incorporation of leucine by a cell-free preparation from Landschütz ascites cells containing ATP and phosphoenolpyruvate. 4. I.C.I. 47776 stimulates glycolysis in suspensions of Landschütz ascites cells in the presence of excess of glucose but has no effect on glycolysis in suspensions of rat lymph-node cells. 5. I.C.I. 47776 markedly depresses ATP concentration in ascites cells in the absence of glucose but has no effect on the ATP concentration in the presence of glucose. The inhibition of protein synthesis by I.C.I. 47776 in ascites cells is, however, only partially reversed by the addition of glucose. 6. The ATP concentration of rat lymph-node cells incubated with I.C.I. 47776 in the absence of glucose is also markedly depressed but the addition of glucose increases the ATP concentration only slightly. Further, glucose has no effect on the inhibition of protein synthesis in lymph-node cells by I.C.I. 47776. 7. It is suggested that I.C.I. 47776 inhibits protein and nucleic acid synthesis in cell suspensions indirectly by acting as a mitochondrial poison. 8. The relevance of studies on the activity of I.C.I. 47776 in vitro to its cytotoxic and immunosuppressive action in vivo is discussed.

scholarly journals Silver Nanoparticles and Their Antibacterial Applications

2021 ◽  
Vol 22 (13) ◽  
pp. 7202
Author(s):  
Tamara Bruna ◽  
Francisca Maldonado-Bravo ◽  
Paul Jara ◽  
Nelson Caro
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Agents ◽  
Multidrug Resistant ◽  
Secondary Effects ◽  
Cytotoxic Effects ◽  
Factors Affecting ◽  
Gram Positive Bacteria ◽  
Resistant Strains

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

scholarly journals E3 ubiquitin ligase Grail promotes hepatic steatosis through Sirt1 inhibition

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Pei-Yao Liu ◽  
Cheng-Cheung Chen ◽  
Chia-Ying Chin ◽  
Te-Jung Liu ◽  
Wen-Chiuan Tsai ◽  
...  
Keyword(s):  
Hepatic Steatosis ◽  
Lipid Accumulation ◽  
Acid Synthesis ◽  
Sirtuin 1 ◽  
Nonalcoholic Fatty Liver ◽  
Expression Of Genes ◽  
Hepatic Fat ◽  
Underlying Mechanisms

AbstractIn obese adults, nonalcoholic fatty liver disease (NAFLD) is accompanied by multiple metabolic dysfunctions. Although upregulated hepatic fatty acid synthesis has been identified as a crucial mediator of NAFLD development, the underlying mechanisms are yet to be elucidated. In this study, we reported upregulated expression of gene related to anergy in lymphocytes (GRAIL) in the livers of humans and mice with hepatic steatosis. Grail ablation markedly alleviated the high-fat diet-induced hepatic fat accumulation and expression of genes related to the lipid metabolism, in vitro and in vivo. Conversely, overexpression of GRAIL exacerbated lipid accumulation and enhanced the expression of lipid metabolic genes in mice and liver cells. Our results demonstrated that Grail regulated the lipid accumulation in hepatic steatosis via interaction with sirtuin 1. Thus, Grail poses as a significant molecular regulator in the development of NAFLD.

Factors affecting in vitro and in vivo antioxidant effects. Experimental conditions and nature of oxidants determine antioxidant efficacy

2021 ◽  
pp. 1-9
Author(s):  
Etsuo Niki
Keyword(s):  
Biological Molecules ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Beneficial Effects ◽  
Multiple Oxidants ◽  
Antioxidant Effects

Reactive oxygen and nitrogen species have been implicated in the onset and progression of various diseases and the role of antioxidants in the maintenance of health and prevention of diseases has received much attention. The action and effect of antioxidants have been studied extensively under different reaction conditions in multiple media. The antioxidant effects are determined by many factors. This review aims to discuss several important issues that should be considered for determination of experimental conditions and interpretation of experimental results in order to understand the beneficial effects and limit of antioxidants against detrimental oxidation of biological molecules. Emphasis was laid on cell culture experiments and effects of diversity of multiple oxidants on antioxidant efficacy.

Maturation, iron deficiency, and ligands in enteric radioiron transport in vitro

1963 ◽  
Vol 204 (1) ◽  
pp. 171-175 ◽  
Author(s):  
W. S. Ruliffson ◽  
J. M. Hopping
Keyword(s):  
Ascorbic Acid ◽  
Iron Deficiency ◽  
Iron Absorption ◽  
Deficiency Anemia ◽  
Anaerobic Incubation ◽  
Reverse Effect ◽  
Factors Affecting ◽  
Everted Gut Sac

The effects in rats, of age, iron-deficiency anemia, and ascorbic acid, citrate, fluoride, and ethylenediaminetetraacetate (EDTA) on enteric radioiron transport were studied in vitro by an everted gut-sac technique. Sacs from young animals transported more than those from older ones. Proximal jejunal sacs from anemic animals transported more than similar sacs from nonanemic rats, but the reverse effect appeared in sacs formed from proximal duodenum. When added to media containing ascorbic acid or citrate, fluoride depressed transport as did anaerobic incubation in the presence of ascorbic acid. Anaerobic incubation in the presence of EDTA appeared to permit elevated transport. Ascorbic acid, citrate, and EDTA all enhanced the level of Fe59 appearing in serosal media. These results appear to agree with previously established in vivo phenomena and tend to validate the in vitro method as one of promise for further studies of factors affecting iron absorption and of the mechanism of iron absorption.

Effect of microbial isolates on microbial yield estimation in RUSITEC system

1998 ◽  
Vol 22 ◽  
pp. 306-308
Author(s):  
M. D. Carro ◽  
E. L. Miller
Keyword(s):  
Protein Synthesis ◽  
Liquid Phase ◽  
Solid Phase ◽  
Liquid Fraction ◽  
Microbial Protein ◽  
Microbial Protein Synthesis ◽  
Continuous Culture System ◽  
The One

The estimation of rumen microbial protein synthesis is one of the main points in the nitrogen (N)-rationing systems for ruminants, as microbial protein provides proportionately 0.4 to 0.9 of amino acids entering the small intestine in ruminants receiving conventional diets (Russell et al., 1992). Methods of estimating microbial protein synthesis rely on marker techniques in which a particular microbial constituent is related to the microbial N content. Marker : N values have generally been established in mixed bacteria isolated from the liquid fraction of rumen digesta and it has been assumed that the same relationship holds in the total population leaving the rumen (Merry and McAllan, 1983). However, several studies have demonstrated differences in composition between solid-associated (SAB) and fluid-associated bacteria in vivo (Legay-Carmier and Bauchart, 1989) and in vitro (Molina Alcaide et al, 1996), as well in marker : N values (Pérez et al., 1996). This problem could be more pronounced in the in vitro semi-continuous culture system RUSITEC, in which there are three well defined components (a free liquid phase, a liquid phase associated with the solid phase and a solid phase), each one having associated microbial populations.The objective of this experiment was to investigate the effect of using different bacterial isolates (BI) on the estimation of microbial production of four different diets in RUSITEC (Czerkawski and Breckenridge, 1977), using (15NH4)2 SO4 as microbial marker, and to assess what effects any differences would have on the comparison of microbial protein synthesis between diets.This study was conducted in conjunction with an in vitro experiment described by Carro and Miller (1997). Two 14-day incubation trials were carried out with the rumen simulation technique RUSITEC (Czerkawski and Breckenridge, 1977). The general incubation procedure was the one described by Czerkawski and Breckenridge (1977) and more details about the procedures of this experiment are given elsewhere (Carro and Miller, 1997).

scholarly journals Phosphorylation of eukaryotic initiation factor 4E (eIF4E) at Ser209 is not required for protein synthesis in vitro and in vivo

2001 ◽  
Vol 268 (20) ◽  
pp. 5375-5385 ◽  
Author(s):  
Linda McKendrick ◽  
Simon J. Morley ◽  
Virginia M. Pain ◽  
Rosemary Jagus ◽  
Bhavesh Joshi
Keyword(s):  
Protein Synthesis ◽  
Initiation Factor ◽  
Eukaryotic Initiation Factor ◽  
Eukaryotic Initiation Factor 4E

scholarly journals Membrane Stored Curvature Elastic Stress Modulates Recruitment of Maintenance Proteins PspA and Vipp1

mBio ◽  
2015 ◽  
Vol 6 (5) ◽  
Author(s):  
Christopher McDonald ◽  
Goran Jovanovic ◽  
Oscar Ces ◽  
Martin Buck
Keyword(s):  
Elastic Stress ◽  
Membrane Binding ◽  
Membrane Integrity ◽  
Regulatory Function ◽  
Membrane Stress ◽  
Inner Membrane ◽  
Thylakoid Biogenesis ◽  
Stress Dependent

ABSTRACTPhage shock protein A (PspA), which is responsible for maintaining inner membrane integrity under stress in enterobacteria, and vesicle-inducting protein in plastids 1 (Vipp1), which functions for membrane maintenance and thylakoid biogenesis in cyanobacteria and plants, are similar peripheral membrane-binding proteins. Their homologous N-terminal amphipathic helices are required for membrane binding; however, the membrane features recognized and required for expressing their functionalities have remained largely uncharacterized. Rigorously controlled,in vitromethodologies with lipid vesicles and purified proteins were used in this study and provided the first biochemical and biophysical characterizations of membrane binding by PspA and Vipp1. Both proteins are found to sense stored curvature elastic (SCE) stress and anionic lipids within the membrane. PspA has an enhanced sensitivity for SCE stress and a higher affinity for the membrane than Vipp1. These variations in binding may be crucial for some of the proteins’ differing rolesin vivo. Assays probing the transcriptional regulatory function of PspA in the presence of vesicles showed that a relief of transcription inhibition occurs in an SCE stress-specific manner. Thisin vitrorecapitulation of membrane stress-dependent transcription control suggests that the Psp response may be mountedin vivowhen a cell's inner membrane experiences increased SCE stress.IMPORTANCEAll cell types maintain the integrity of their membrane systems. One widely distributed membrane stress response system in bacteria is the phage shock protein (Psp) system. The central component, peripheral membrane protein PspA, which mitigates inner membrane stress in bacteria, has a counterpart, Vipp1, which functions for membrane maintenance and thylakoid biogenesis in plants and photosynthetic bacteria. Membrane association of both these proteins is accepted as playing a pivotal role in their functions. Here we show that direct membrane binding by PspA and Vipp1 is driven by two physio-chemical signals, one of which is membrane stress specific. Our work points to alleviation of membrane stored curvature elastic stress by amphipathic helix insertions as an attractive mechanism for membrane maintenance by PspA and Vipp1. Furthermore, the identification of a physical, stress-related membrane signal suggests a unilateral mechanism that promotes both binding of PspA and induction of the Psp response.

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