Stable isotope fractionation by Clostridium pasteurianum. 3. Effect of SeO32– on the physiology and associated sulfur isotope fractionation during SeO32– and SeO42– reductions

1980 ◽  
Vol 26 (8) ◽  
pp. 952-958 ◽  
Author(s):  
G. I. Harrison ◽  
E. J. Laishley ◽  
H. R. Krouse
Keyword(s):  
Isotope Fractionation ◽  
Chemical Mechanism ◽  
Clostridium Pasteurianum ◽  
Whole Cells ◽  
In Vivo Experiments ◽  
Stable Isotope Fractionation ◽  
Sulfur Isotope Fractionation ◽  
Generation Times

Increased [Formula: see text] concentration reduced H2S evolution from [Formula: see text] during whole cell and cell-free extract reductions by Clostridium pasteurianum. H2S production from [Formula: see text] was completely inhibited by [Formula: see text] in stationary phase cells. Generation times increased with greater [Formula: see text] concentration, the increase with 1 mM[Formula: see text] being a factor of 2.5 for 1 mM[Formula: see text], and over 3 for 1 mM[Formula: see text] reductions. In vitro and in vivo experiments with proposed intermediates of the [Formula: see text] reduction pathway show that [Formula: see text] inhibited both the [Formula: see text] to [Formula: see text] and [Formula: see text] to S2− reaction sequences with the latter being more pronounced in growth experiments. Both extracts and whole cells reduced [Formula: see text], to Se0 but Se0 granules were not found in the cell's cytoplasm. The formation of [Formula: see text] by an extracellular chemical mechanism appears not to have occurred in these experiments. Increased [Formula: see text] concentration had the effect of compressing the isotopic release pattern for H2S along the H2S production axis and did not significantly alter the maximum and mimimum values of δ34S. Thus, inhibition by [Formula: see text] limited the conversions of sulfur species without altering the isotopic selectivity of rate-controlling steps in the pathway.

Stable isotope fractionation by Clostridium pasteurianum. 5. Effect of SeO42− on the physiology and associated sulfur isotope fractionation during SO32− and SO42− reductions

1982 ◽  
Vol 28 (3) ◽  
pp. 325-333 ◽  
Author(s):  
G. I. Harrison ◽  
E. J. Laishley ◽  
H. R. Krouse
Keyword(s):  
Stationary Phase ◽  
Isotope Fractionation ◽  
Sulfur Isotope ◽  
Reductase Activity ◽  
Clostridium Pasteurianum ◽  
Elemental Selenium ◽  
Whole Cells ◽  
Stable Isotope Fractionation ◽  
Sulfur Isotope Fractionation ◽  
Inverse Isotope Effect

The addition of 1 mM SeO42− significantly affected the physiology and metabolism of Clostridium pasteurianum growing on SO42− in the following ways: (1) the generation time was increased, essentially producing a biphasic growth curve, (2) cells became elongated and chains formed, (3) no H2S was liberated during the stationary phase, (4) assimilatory SO32− reductase activity was decreased, (5) ferredoxin levels decreased by a factor of 4. The effects of 1 mM SeO42− on Clostridium pasteurianum growing on SO32− were comparatively minor.H2S evolution in the stationary phase decreased by a factor of 2 and the δ34S maximum in the inverse isotope effect pattern occurred at a slightly lower percent H2S evolution. The deleterious effects of SeO42− addition were less pronounced than those associated with SeO32− addition. SeO32− but not SeO42− was reduced to elemental selenium by both whole cells and crude extracts.

Stable isotope fractionation by Clostridium pasteurianum. 4. Sulfur isotope fractionation during enzymatic S3O62−, S2O32−, and SO32− reductions

1981 ◽  
Vol 27 (8) ◽  
pp. 824-834
Author(s):  
G. I. Harrison ◽  
E. J. Laishley ◽  
H. R. Krouse
Keyword(s):  
Stable Isotope ◽  
Isotope Fractionation ◽  
Sulfur Isotope ◽  
Isotope Effects ◽  
Growth Conditions ◽  
Enzyme Concentration ◽  
Clostridium Pasteurianum ◽  
Relative Reduction ◽  
Stable Isotope Fractionation ◽  
Sulfur Isotope Fractionation

Cell-free extracts from Clostridium pasteurianum grown on SO32− utilize H2 to reduce S3O62−, S2O32−, and SO32− to H2S at a much faster rate than extracts from SO42−-grown cells. This further supports the concept of an inducible dissimilatory type SO32− reductive pathway in this organism. 35S dilution experiments further support the concept that S3O62− and S2O32− are pathway intermediates. The inducible SO32− reductase is ferredoxin linked and the kinetics of the reduction and the sulfur isotope fractionation of the product can be altered by altering the growth conditions. The attending sulfur isotope fractionations are similar to those observed during the chemical decomposition of these compounds. In the case of S2O32−, 35S labelling experiments verified the conclusions derived from the stable isotope fractionation data concerning the relative reduction rates of the sulfane and sulfonate sulfurs. The reduction rates were also affected by enzyme concentration. The integrity of the whole cell is a necessary requirement for the large inverse isotope effects previously reported.

Stable isotope fractionation by Clostridium pasteurianum. 2. Regulation of sulfite reductases by sulfur amino acids and their influence on sulfur isotope fractionation during SO32− and SO42− reduction

1978 ◽  
Vol 24 (6) ◽  
pp. 716-724 ◽  
Author(s):  
E. J. Laishley ◽  
H. R. Krouse
Keyword(s):  
Amino Acids ◽  
Isotope Fractionation ◽  
Sulfur Isotope ◽  
Sulfite Reductase ◽  
Clostridium Pasteurianum ◽  
Sulfur Amino Acids ◽  
Stable Isotope Fractionation ◽  
Sulfur Isotope Fractionation ◽  
Sulfide Production ◽  
Logarithmic Growth

In addition to an assimilatory sulfite reductase, studies of cultures of Clostridium pasteurianum supplemented with methionine, cysteine, and 35SO42− provide evidence for another reductase which is induced by SO32−. This inducible reductase appears to be dissimilatory because of the copious sulfide production arising when the cells are grown on SO32−. Cysteine can repress the assimilatory sulfite reductase but does not affect the inducible reductase. During late logarithmic growth on 1 mM SO42− + 10 mM cysteine, derepression of the inducible reductase occurred along with increased sulfide production. The presence of 1 mM cysteine and (or) 1 mM methionine does not affect the inverse sulfur isotope effect for evolved H2S. However, 5 and 10 mM cysteine reduce the maximum δ34S value for released H2S from +40 to +10‰. A small conversion of cysteine to H2S by C. pasteurianum occurs, but only in the stationary phase.

scholarly journals Brucella suis-Impaired Specific Recognition of Phagosomes by Lysosomes due to Phagosomal Membrane Modifications

2001 ◽  
Vol 69 (1) ◽  
pp. 486-493 ◽  
Author(s):  
Aroem Naroeni ◽  
Nicolas Jouy ◽  
Safia Ouahrani-Bettache ◽  
Jean-Pierre Liautard ◽  
Françoise Porte
Keyword(s):  
Fluorescence Microscopy ◽  
Phagocytic Cells ◽  
Whole Cells ◽  
Specific Recognition ◽  
In Vivo Experiments ◽  
In Vitro Reconstitution ◽  
Brucella Suis ◽  
Phagosomal Membrane

ABSTRACT Brucella species are gram-negative, facultatively intracellular bacteria that infect humans and animals. These organisms can survive and replicate within a membrane-bound compartment in phagocytic and nonprofessional phagocytic cells. Inhibition of phagosome-lysosome fusion has been proposed as a mechanism for intracellular survival in both types of cells. However, the biochemical mechanisms and microbial factors implicated in Brucellamaturation are still completely unknown. We developed two different approaches in an attempt to gain further insight into these mechanisms: (i) a fluorescence microscopy analysis of general intracellular trafficking on whole cells in the presence of Brucella and (ii) a flow cytometry analysis of in vitro reconstitution assays showing the interaction between Brucella suis-containing phagosomes and lysosomes. The fluorescence microscopy results revealed that fusion properties of latex bead-containing phagosomes with lysosomes were not modified in the presence of live Brucella suis in the cells. We concluded that fusion inhibition was restricted to the pathogen phagosome and that the host cell fusion machinery was not altered by the presence of live Brucellain the cell. By in vitro reconstitution experiments, we observed a specific association between killed B. suis-containing phagosomes and lysosomes, which was dependent on exogenously supplied cytosol, energy, and temperature. This association was observed with killed bacteria but not with live bacteria. Hence, this specific recognition inhibition seemed to be restricted to the pathogen phagosomal membrane, as noted in the in vivo experiments.

ANTITUMOR EFFECT OF COLLOIDAL SILVER BISILICATE IN EXPERIMENTAL IN VITRO AND IN VIVO STUDIES

2019 ◽  
Vol 65 (5) ◽  
pp. 760-765
Author(s):  
Margarita Tyndyk ◽  
Irina Popovich ◽  
A. Malek ◽  
R. Samsonov ◽  
N. Germanov ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Human Tumor ◽  
Significant Inhibition ◽  
In Vivo Studies ◽  
Ehrlich Carcinoma ◽  
In Vivo Experiments

The paper presents the results of the research on the antitumor activity of a new drug - atomic clusters of silver (ACS), the colloidal solution of nanostructured silver bisilicate Ag6Si2O7 with particles size of 1-2 nm in deionized water. In vitro studies to evaluate the effect of various ACS concentrations in human tumor cells cultures (breast cancer, colon carcinoma and prostate cancer) were conducted. The highest antitumor activity of ACS was observed in dilutions from 2.7 mg/l to 5.1 mg/l, resulting in the death of tumor cells in all studied cell cultures. In vivo experiments on transplanted Ehrlich carcinoma model in mice consuming 0.75 mg/kg ACS with drinking water revealed significant inhibition of tumor growth since the 14th day of experiment (maximally by 52% on the 28th day, p < 0.05) in comparison with control. Subcutaneous injections of 2.5 mg/kg ACS inhibited Ehrlich's tumor growth on the 7th and 10th days of the experiment (p < 0.05) as compared to control.

scholarly journals Plant-Derived Extracellular Vesicles: Current Findings,Challenges, and Future Applications

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 411
Author(s):  
Nader Kameli ◽  
Anya Dragojlovic-Kerkache ◽  
Paul Savelkoul ◽  
Frank R. Stassen
Keyword(s):  
Human Health ◽  
Extracellular Vesicles ◽  
Preliminary Results ◽  
In Vivo Experiments ◽  
Health And Disease ◽  
Conducting Research ◽  
Protocol Standardization ◽  
Insight Into

In recent years, plant-derived extracellular vesicles (PDEVs) have gained the interest of many experts in fields such as microbiology and immunology, and research in this field has exponentially increased. These nano-sized particles have provided researchers with a number of interesting findings, making their application in human health and disease very promising. Both in vitro and in vivo experiments have shown that PDEVs can exhibit a multitude of effects, suggesting that these vesicles may have many potential future applications, including therapeutics and nano-delivery of compounds. While the preliminary results are promising, there are still some challenges to face, such as a lack of protocol standardization, as well as knowledge gaps that need to be filled. This review aims to discuss various aspects of PDEV knowledge, including their preliminary findings, challenges, and future uses, giving insight into the complexity of conducting research in this field.

scholarly journals Osteoprotective Effects of Loganic Acid on Osteoblastic and Osteoclastic Cells and Osteoporosis-Induced Mice

2020 ◽  
Vol 22 (1) ◽  
pp. 233
Author(s):  
Eunkuk Park ◽  
Chang Gun Lee ◽  
Eunguk Lim ◽  
Seokjin Hwang ◽  
Seung Hee Yun ◽  
...  
Keyword(s):  
Osteoclast Differentiation ◽  
Osteoblastic Differentiation ◽  
Common Disease ◽  
Root Extract ◽  
Mouse Bone Marrow ◽  
Mineral Density ◽  
Bone Mineral Density Loss ◽  
In Vivo Experiments

Osteoporosis is a common disease caused by an imbalance of processes between bone resorption by osteoclasts and bone formation by osteoblasts in postmenopausal women. The roots of Gentiana lutea L. (GL) are reported to have beneficial effects on various human diseases related to liver functions and gastrointestinal motility, as well as on arthritis. Here, we fractionated and isolated bioactive constituent(s) responsible for anti-osteoporotic effects of GL root extract. A single phytochemical compound, loganic acid, was identified as a candidate osteoprotective agent. Its anti-osteoporotic effects were examined in vitro and in vivo. Treatment with loganic acid significantly increased osteoblastic differentiation in preosteoblast MC3T3-E1 cells by promoting alkaline phosphatase activity and increasing mRNA expression levels of bone metabolic markers such as Alpl, Bglap, and Sp7. However, loganic acid inhibited osteoclast differentiation of primary-cultured monocytes derived from mouse bone marrow. For in vivo experiments, the effect of loganic acid on ovariectomized (OVX) mice was examined for 12 weeks. Loganic acid prevented OVX-induced bone mineral density loss and improved bone structural properties in osteoporotic model mice. These results suggest that loganic acid may be a potential therapeutic candidate for treatment of osteoporosis.

scholarly journals Regorafenib-Attenuated, Bleomycin-Induced Pulmonary Fibrosis by Inhibiting the TGF-β1 Signaling Pathway

2021 ◽  
Vol 22 (4) ◽  
pp. 1985
Author(s):  
Xiaohe Li ◽  
Ling Ma ◽  
Kai Huang ◽  
Yuli Wei ◽  
Shida Long ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Kinase Inhibitor ◽  
In Vivo Experiments ◽  
Age Related ◽  
And Migration ◽  
Tgf Β1

Idiopathic pulmonary fibrosis (IPF) is a fatal and age-related pulmonary disease. Nintedanib is a receptor tyrosine kinase inhibitor, and one of the only two listed drugs against IPF. Regorafenib is a novel, orally active, multi-kinase inhibitor that has similar targets to nintedanib and is applied to treat colorectal cancer and gastrointestinal stromal tumors in patients. In this study, we first identified that regorafenib could alleviate bleomycin-induced pulmonary fibrosis in mice. The in vivo experiments indicated that regorafenib suppresses collagen accumulation and myofibroblast activation. Further in vitro mechanism studies showed that regorafenib inhibits the activation and migration of myofibroblasts and extracellular matrix production, mainly through suppressing the transforming growth factor (TGF)-β1/Smad and non-Smad signaling pathways. In vitro studies have also indicated that regorafenib could augment autophagy in myofibroblasts by suppressing TGF-β1/mTOR (mechanistic target of rapamycin) signaling, and could promote apoptosis in myofibroblasts. In conclusion, regorafenib attenuates bleomycin-induced pulmonary fibrosis by suppressing the TGF-β1 signaling pathway.

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