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41.
Electron Microscope Observations on the Fine Structure of Parietal Cells 总被引:16,自引:15,他引:1
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An electron microscope study has been made of the structure of parietal cells in cats, dogs, and rats and of the cells lining the gastric glands of Bufo spinulosus. It is characteristic of all these cells to contain numerous vesicles about 0.05 to 0.3 µ in size. In the mammalian parietal cells an intracellular system of canaliculi is also observed, which is much more complex in the rat than in the cat or dog. Stimulation with histamine causes in the cat a very marked hypertrophy of the canalicular system with development of a large number of villi and a decrease in the number of vesicles. In Bufo, histamine induces the formation of a very complex system of membrane infoldings which circumscribe finger-like processes that entirely fill the glandular lumen. The cytoplasmic vesicles diminish or disappear. These experiments show that under histamine stimulation all these cells undergo a great increase in the cell membrane area. These findings provide additional circumstantial evidence that parietal cells play a role in the secretion of hydrochloric acid. 相似文献
42.
The bioelectric characterization of bull spermatozoa was based on the establishment of a standard, for comparison with cells subjected to manipulation of the ionic environment. In addition to potassium and sodium, chloride concentration was also found to have an effect on bull spermatozoa membrane potential and motility. The chloride effect on potential was similar in magnitude to that of sodium but smaller than that of potassium. Potential difference in potassium, sodium and chloride supplemented media was related to the amplitude of the flagellar wave. 相似文献
43.
Proteinase K Processing of Rabbit Muscle Creatine Kinase 总被引:2,自引:0,他引:2
Chantal Leydier Jens S. Andersen Fabienne Couthon Eric Forest Olivier Marcillat Luc Denoroy Christian Vial Eric Clottes 《Journal of Protein Chemistry》1997,16(1):67-74
Proteinase K cleaves selectively both cytosolic and mitochondrial isoforms of creatine kinase leading to the appearance of two fragments, a large N-terminal one (K1) and a small C-terminal peptide (K2) which remain associated together. The loss of enzymatic activity correlates with the extent of monomer cleavage. N-terminal sequencing of the K2 fragments from rabbit cytosolic and pig mitochondrial creatine kinase shows that these peptides begin with A328 and A324, respectively. Electrospray ionization mass spectrometry demonstrates that K2 peptide is composed of 53 residues (A328–K380). However, the C-terminal end of the K1 fragment is not A327 as expected, but D325. Thus, the amino acids residues T326 and A327 have been eliminated by the protease. 相似文献
44.
S Duthel M Bost E Ollagnon C Vial P Petiot G Chazot A Vandenberghe 《Annales de génétique》1999,42(3):151-159
We report clinical, genetical and genealogical findings in 149 French families from the Rh?ne-Alpes area studied over a 5-year period. There was a significant excess of DM females compared to DM males with (CTG) repeat sizes between 1-2 kb. The mean maternal (CTG) repeat size was higher than paternal repeat size. Anticipation phenomenom was significantly higher after maternal than after paternal transmission. A significant correlation between parental (CTG) repeat size and intergenerational variation both in paternal and maternal transmissions was observed. The anticipation phenomenom was more important for sons than daughters particularly after maternal transmission. The mean (CTG) repeat size in mothers of CDM cases was about twice that of mothers of NCDM children. The risk of giving birth to a CDM child increased considerably when the number of maternal (CTG) repeats was over 300 (CTG). A significant excess of DM females was observed. They had on average 24% fewer children than male patients. Paternal transmission (63.6%) of DM occurred more frequently than maternal transmission (52.7%). 相似文献
45.
AMPKα1‐LDH pathway regulates muscle stem cell self‐renewal by controlling metabolic homeostasis
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Marine Theret Gaëtan Juban Sabrina Ben Larbi Michèle Weiss‐Gayet Laurent Bultot Marc Foretz Dominique Desplanches Pascual Sanz Zizhao Zang Lin Yang Guillaume Vial Benoit Viollet Kei Sakamoto Anne Brunet Bénédicte Chazaud Rémi Mounier 《The EMBO journal》2017,36(13):1946-1962
Control of stem cell fate to either enter terminal differentiation versus returning to quiescence (self‐renewal) is crucial for tissue repair. Here, we showed that AMP‐activated protein kinase (AMPK), the master metabolic regulator of the cell, controls muscle stem cell (MuSC) self‐renewal. AMPKα1?/? MuSCs displayed a high self‐renewal rate, which impairs muscle regeneration. AMPKα1?/? MuSCs showed a Warburg‐like switch of their metabolism to higher glycolysis. We identified lactate dehydrogenase (LDH) as a new functional target of AMPKα1. LDH, which is a non‐limiting enzyme of glycolysis in differentiated cells, was tightly regulated in stem cells. In functional experiments, LDH overexpression phenocopied AMPKα1?/? phenotype, that is shifted MuSC metabolism toward glycolysis triggering their return to quiescence, while inhibition of LDH activity rescued AMPKα1?/? MuSC self‐renewal. Finally, providing specific nutrients (galactose/glucose) to MuSCs directly controlled their fate through the AMPKα1/LDH pathway, emphasizing the importance of metabolism in stem cell fate. 相似文献
46.
Sílvia Vieira Stephanie Vial Rui L. Reis J. Miguel Oliveira 《Biotechnology progress》2017,33(3):590-611
Tissue engineering (TE) envisions the creation of functional substitutes for damaged tissues through integrated solutions, where medical, biological, and engineering principles are combined. Bone regeneration is one of the areas in which designing a model that mimics all tissue properties is still a challenge. The hierarchical structure and high vascularization of bone hampers a TE approach, especially in large bone defects. Nanotechnology can open up a new era for TE, allowing the creation of nanostructures that are comparable in size to those appearing in natural bone. Therefore, nanoengineered systems are now able to more closely mimic the structures observed in naturally occurring systems, and it is also possible to combine several approaches ‐ such as drug delivery and cell labeling ‐ within a single system. This review aims to cover the most recent developments on the use of different nanoparticles for bone TE, with emphasis on their application for scaffolds improvement; drug and gene delivery carriers, and labeling techniques. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:590–611, 2017 相似文献
47.
48.
Fernández V Tapia G Varela P Gaete L Vera G Mora C Vial MT Videla LA 《Free radical biology & medicine》2008,44(9):1724-1731
Hepatic ischemia-reperfusion (IR) injury, a major clinical drawback during surgery, is abolished by L-3,3',5-triiodothyronine (T(3)) administration. Considering that the triggering mechanisms are unknown, the aim of this study is to assess the role of oxidative stress in T(3) preconditioning using N-acetylcysteine (NAC) before T(3) administration. Male Sprague-Dawley rats given a single dose of 0.1 mg of T(3)/kg were subjected to 1 h ischemia followed by 20 h reperfusion, in groups of animals pretreated with 0.5 g of NAC/kg 0.5 h before T(3) or with the respective control vehicles. At the end of the reperfusion period, blood and liver samples were taken for analysis of serum aspartate aminotransferase (AST) and hepatic histology, glutathione (GSH) and protein carbonyl contents, and nuclear factor-kappaB (NF-kappaB) and activating protein 1 (AP-1) DNA binding. The IR protocol used led to a 4.5-fold increase in serum AST levels and drastic changes in liver histology, with significant GSH depletion and enhancement of protein carbonyl levels and of the protein carbonyl/GSH content ratio, whereas NF-kappaB and AP-1 DNA binding was decreased and enhanced, respectively. In a time window of 48 h, T(3) exerted protection against hepatic IR injury, with 88% reduction in the protein carbonyl/GSH ratio and normalization of NF-kappaB and AP-1 DNA binding, changes that were suppressed by NAC administration before T(3). Data presented suggest that a transient increase in the oxidative stress status of the liver is an important trigger for T(3) preconditioning, evidenced in a warm IR injury model through antioxidant intervention. 相似文献
49.
Burkholderia pseudomallei, B. thailandensis, and B. ambifaria produce 4-hydroxy-2-alkylquinoline analogues with a methyl group at the 3 position that is required for quorum-sensing regulation
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Vial L Lépine F Milot S Groleau MC Dekimpe V Woods DE Déziel E 《Journal of bacteriology》2008,190(15):5339-5352
4-Hydroxy-2-alkylquinolines (HAQs), especially 3,4-dihydroxy-2-heptylquinoline (Pseudomonas quinolone signal) and its precursor, 4-hydroxy-2-heptylquinoline, are attracting much attention, mainly because of their role as signaling molecules in Pseudomonas aeruginosa. The pqsABCDE operon is centrally involved in their biosynthesis. The presence of a homologous operon in Burkholderia pseudomallei and B. thailandensis was recently reported. Thus, we have investigated the abilities of 11 Burkholderia species to produce HAQ-like molecules by liquid chromatography/mass spectrometry. We have identified 29 different HAQ derivatives produced by the only three Burkholderia species where a pqsABCDE homologue was found among available sequenced Burkholderia species genomes, including B. ambifaria, a member of the Burkholderia cepacia complex. In contrast with those of P. aeruginosa, Burkholderia HAQs typically bear a methyl group, hence their designation as 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs). We identified three families of HMAQs with a saturated or unsaturated alkyl chain at the 2' position, in contrast with the 1' position of P. aeruginosa, including one with an N-oxide group. Furthermore, the operon in these species contains two more genes downstream of the pqsE homologue, resulting in the hmqABCDEFG operon. While the inactivation of hmqA inhibits the production of HMAQs, the methylation of the quinoline ring requires a putative methyltransferase encoded by hmqG. Interestingly, hmqA or hmqG mutations increase the production of acyl homoserine lactones and, consequently, phenotypes under the control of quorum sensing in B. ambifaria: antifungal activity, siderophore production, and proteolytic activity. These results indicate that only HAQs bearing a methyl group (HMAQs) are involved in quorum-sensing regulation. 相似文献
50.
María V. Niklison-Chirou Fernando Dupuy Liliana B. Pena Susana M. Gallego Maria Laura Barreiro-Arcos Cesar Avila Clarisa Torres-Bugeau Beatriz E. Arcuri Augusto Bellomio Carlos Minahk Roberto D. Morero 《The international journal of biochemistry & cell biology》2010,42(2):273-281
We previously showed that the antimicrobial peptide microcin J25 induced the over-production of reactive oxygen species with the concomitant release of cytochrome c from rat heart mitochondria via the opening of the mitochondrial permeability transition pore. Here, we were able to demonstrate that indeed, as a consequence of the oxidative burst, MccJ25 induces carbonylation of mitochondrial proteins, which may explain the irreversible inhibition of complex III and the partial inhibition of superoxide dismutase and catalase. Moreover, the peptide raised the levels of oxidized membrane lipids, which triggers the release of cytochrome c. From in silico analysis, we hypothesize that microcin would elicit these effects through interaction with heme c1 at mitochondrial complex III. On the other hand, under an excess of l-arginine, MccJ25 caused nitric oxide overproduction with no oxidative damage and a marked inhibition in oxygen consumption. Therefore, a beneficial anti-oxidative activity could be favored by the addition of l-arginine. Conversely, MccJ25 pro-oxidative–apoptotic effect can be unleashed in either an arginine-free medium or by suppressing the nitric oxide synthase activity. 相似文献