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71.
N-phthaloyl GABA (P. GABA) inhibited gastric ulceration induced by 3 hr restraint stress at 4 degrees C (CRS) in albino rats. Antiulcer activity of P. GABA was compared with sodium valproate and cimetidine. P. GABA, sodium valproate and cimetidine showed a dose dependent reduction of gastric ulceration. Pretreatment with GABA antagonists-bicuculline methiodide (0.5 mg/kg, im) or 3 mercaptopropionic acid (2 mg/kg, im) reversed the antiulcerogenic activity of both the drugs (P. GABA and sodium valproate). GABA antagonists as such did not induce gastric ulceration in normal rats. 相似文献
72.
Low‐pH and Al3+ stresses are the major causes of poor plant growth in acidic soils. However, there is still a poor understanding of plant responses to low‐pH and Al3+ toxicity. Low‐pH or combined low‐pH and Al3+ stress was imposed in order to measure rhizosphere pH, ion fluxes, plasma membrane potential and intracellular H+ concentration in distal elongation and mature zones (MZs) along the longitudinal axis of Arabidopsis thaliana roots. Low‐pH stress facilitated H+ influx into root tissues and caused cytoplasmic acidification; by contrast, combined low‐pH/Al3+ treatment either decreased H+ influx in the distal elongation zone (DEZ) or induced H+ efflux in the MZ, leading to cytoplasmic alkalinization in both zones. Low‐pH stress induced an increase in rhizosphere pH in the DEZ, whereas combined low‐pH/Al3+ stress resulted in lower rhizosphere pH in both root zones compared with the low‐pH treatment alone. Low‐pH stress facilitated K+ efflux; the presence of Al3+ diminished K+ efflux or favored K+ influx into root tissues. In both zones, low‐pH treatment induced plasma membrane (PM) depolarization, which was significantly diminished (P≤ 0.05) when combined stresses (low‐pH/100 µM Al3+) were imposed. After 60 min of exposure, low pH caused PM depolarization, whereas low pH/100 µM Al3+ caused PM hyperpolarization. Thus, low pH and Al3+ toxicity differentially affect root tissues and, consequently, the rhizosphere, which might underpin the differential mechanisms of plant adaptation to these abiotic stresses. 相似文献
73.
Boral S Gupta AN Bohidar HB 《International journal of biological macromolecules》2006,39(4-5):240-249
Controlled osmotic swelling and de-swelling measurements have been performed on gelatin, a polyampholyte, hydrogels suspended in water-ethanol marginal solvent at room temperature (20 degrees C) where the alcohol concentration was changed from 0 to 100% (v/v). The change in gel mass was monitored as function of time until osmotic equilibrium was established with the surrounding solvent. It was observed that osmotic pressure of polymer-solvent mixing, pi(m)相似文献
74.
Debayan Bose Anh H. Ngo Van C. Nguyen Yuki Nakamura 《The Plant journal : for cell and molecular biology》2021,106(2):409-418
Non-specific phospholipase Cs (NPCs) are responsible for membrane lipid remodeling that involves hydrolysis of the polar head group of membrane phospholipids. Arabidopsis NPC2 and NPC6 are essential in gametogenesis, but their underlying role in the lipid remodeling remains elusive. Here, we show that these NPCs are required for triacylglycerol (TAG) production in pollen tube growth. NPC2 and NPC6 are highly expressed in developing pollen tubes and are localized at the endoplasmic reticulum. Mutants of NPC2 and NPC6 showed reduced rate of pollen germination, length of pollen tube and amount of lipid droplets (LDs). Overexpression of NPC2 or NPC6 induced LD accumulation, which suggests that these NPCs are involved in LD production. Furthermore, mutants defective in the biosynthesis of TAG, a major component of LDs, showed defective pollen tube growth. These results suggest that NPC2 and NPC6 are essential in gametogenesis for a role in hydrolyzing phospholipids and producing TAG required for pollen tube growth. Thus, lipid remodeling from phospholipids to TAG during pollen tube growth represents an emerging role for the NPC family in plant developmental control. 相似文献
75.
Arijita Basu Priyanka Upadhyay Avijit Ghosh Aparajita Bose Payal Gupta Sreya Chattopadhyay Dipankar Chattopadhyay Arghya Adhikary 《Biochimica et Biophysica Acta (BBA)/General Subjects》2021,1865(3):129841
BackgroundTriple negative breast cancer (TNBC) is the most aggressive form of breast cancer with limited treatment modalities. It is associated with high propensity of cancer recurrence.MethodsUV Spectroscopy, FTIR, DLS, Zeta potential, TEM and SEM were employed to characterize nanoparticles. MTT assay, Wound healing assay, SEM, Immunocytochemistry analysis, Western blot, RT-PCR, mammosphere formation assay were employed to study apoptosis, cell migration and stemness. Tumor regression was studied in chick embryo xenograft and BALB/c mice model.ResultsHylaluronic acid engrafted metformin loaded graphene oxide (HA-GO-Met) nanoparticles exhibited an anti-cancer efficacy at much lower dosage as compared to metformin alone. HA-GO-Met nanoparticles induced apoptosis and inhibited cell migration of TNBC cells by targeting miR-10b/PTEN axis via NFkB-p65. Upregulation of PTEN affected pAKT(473) expression that induced apoptosis. Cell migration was inhibited by reduction of pFAK/integrinβ1 expressions. Treatment inhibited epithelial mesenchymal transition (EMT) and reduced stemness as evident from the increase in E-cadherin expression, inhibition of mammosphere formation and low expression levels of stemness markers including nanog, oct4 and sox2 as compared to control. Moreover, tumor regression was studied in chick embryo xenograft and BALB/c mice model. HA-GO-Met nanoparticle treatment reduced tumor load and nullified toxicity in peripheral organs imparted by tumor.ConclusionsHA-GO-Met nanoparticles exhibited an enormous anti-cancer efficacy in TNBC in vitro and in vivo.General significanceHA-GO-Met nanoparticles induced apoptosis and attenuated cell migration in TNBC. It nullified overall toxicity imparted by tumor load. It inhibited EMT and reduced stemness and thereby addressed the issue of cancer recurrence. 相似文献
76.
The enzyme fraction A, a constituent enzyme of the three-fraction enzyme mycobacillin synthetase, independently and sequentially activated five amino acids starting from L-proline, producing the pentapeptide Pro(Asp1,Glu1,Tyr1)Asp. The fractions B and C were unable to function independently. However, the fraction B synthesized the nonapeptide Pro(Asp3,Glu1,Tyr2,Ser1)Leu, sequentially activating the pentapeptide and next four amino acids, whereas the fraction C synthesized mycobacillin by the sequential activation of the nonapeptide and the remaining four amino acids. The pH optima of the above enzymes are almost identical (pH 7.8), but their Km values are a little different. 相似文献
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Loss of cell wall alpha(1-3) glucan affects Cryptococcus neoformans from ultrastructure to virulence 总被引:1,自引:0,他引:1
Reese AJ Yoneda A Breger JA Beauvais A Liu H Griffith CL Bose I Kim MJ Skau C Yang S Sefko JA Osumi M Latge JP Mylonakis E Doering TL 《Molecular microbiology》2007,63(5):1385-1398
Yeast cell walls are critical for maintaining cell integrity, particularly in the face of challenges such as growth in mammalian hosts. The pathogenic fungus Cryptococcus neoformans additionally anchors its polysaccharide capsule to the cell surface via alpha(1-3) glucan in the wall. Cryptococcal cells disrupted in their alpha glucan synthase gene were sensitive to stresses, including temperature, and showed difficulty dividing. These cells lacked surface capsule, although they continued to shed capsule material into the environment. Electron microscopy showed that the alpha glucan that is usually localized to the outer portion of the cell wall was absent, the outer region of the wall was highly disorganized, and the inner region was hypertrophic. Analysis of cell wall composition demonstrated complete loss of alpha glucan accompanied by a compensatory increase in chitin/chitosan and a redistribution of beta glucan between cell wall fractions. The mutants were unable to grow ina mouse model of infection, but caused death in nematodes. These studies integrate morphological and biochemical investigations of the role of alpha glucan in the cryptococcal cell wall. 相似文献