牡砺糖胺聚糖对血管内皮细胞损伤的保护作用研究

目的：探讨牡蛎糖胺聚糖（O—GAG）对血管内皮细胞损伤的保护作用,观察它对损伤的血管内皮细胞内一氧化氮（NO）、丙二醛（iDA）含量及乳酸脱氢酶（LDH）活性的影响。方法：采用人脐静脉内皮细胞株ECV304体外培养的方法,建立过氧化氢（H2O2）诱导的内皮细胞损伤模型,噻唑蓝（MTT）比色法观察牡蛎糖胺聚糖对血管内皮细胞增殖活性的影响,硝酸还原酶法、硫代巴比妥酸法和硝基苯肼法分别检测细胞内NO的含量、细胞培养液内MDA的含量和LDH的活性。结果：模型组较正常对照组细胞增殖活性明显降低（P〈0．01）。与模型组相比,经牡蛎糖胺聚糖预处理的各保护组（除10μg／ml）细胞增殖活性明显增加（P〈0．05,P〈0．01）,NO的含量增加,MDA的含量和LDH的活性降低（P〈0．01）。牡蛎糖胺聚糖（100、200μg／ml）对于正常的内皮细胞有促增殖作用（P〈0．05）。结论：牡蛎糖胺聚糖对氧化损伤的血管内皮细胞具有保护作用,其作用机制可能与增加细胞NO含量、减少MDA生成和LDH释放有关。牡蛎糖胺聚糖对正常血管内皮细胞在一定剂量范围内有促增殖作用．     

A gene controlling the early development of protoperithecium in Neurospora crassa

Summary A mutation (ff-1) which specifically destroys the ability to develop protoperithecia was found in Neurospora crassa. This mutation causes no change in vegetative morphology. It is located between arg-5 and try-3 on the right arm of linkage group II.     

Sensitivity to Ultraviolet Light of Tobacco Mosaic Virus Modified by Cetyltrimethylammonium Bromide

Cetyltrimethylammonium bromide (CTAB) modified tobacco mosaic virus (TMV) virions so that the intrinsic fluorescence changed, viral infectivity decreased, sensitivity to RNase or UV irradiation increased, and coat protein subunits were released by the addition of Triton X-100. The change in fluorescence emission at 320 nm shifted to 340 nm was observed at 100 μg of CTAB per ml. This represents a change in the tryptophan environment inside the virion. At a lower concentration of CTAB, intersubunit contact was weakened, resulting in the release of coat protein subunits and an increase in RNase sensitivity. The release of coat protein took place gradually and two relatively stable intermediates were observed. Increase in UV sensitivity was observed at a lower concentration of CTAB and formation of pyrimidine hydrate was involved in this inactivation. The nature of the minor structural change leading to UV inactivation is discussed.     

Optimization of process parameters for the continuous production of alcohol with a cell immobilized bioreactor

The optimum values of substrate concentration, pH and temperature for higher yields of alcohol in cell immobilized bioreactor using alginate entrapped cells of yeasts for continuous fermentation of alcohol were obtained employing full factorial search. The results indicate that the yield of alcohol is predominantly influenced by the substrate concentration and temperature, both individually and in combination. The pH, on the other hand, has no significant influence. The path of steepest ascent method has been used to optimise the alcohol yield. A best alcohol yield has been obtained with 23.5% substrate concentration, 30°C temperature and at pH 5.0.     

Modulating HIV-1 envelope glycoprotein conformation to decrease the HIV-1 reservoir

1. Download : Download high-res image (131KB)
2. Download : Download full-size image

     

A single dose of the SARS-CoV-2 vaccine BNT162b2 elicits Fc-mediated antibody effector functions and T cell responses

1. Download : Download high-res image (115KB)
2. Download : Download full-size image

     

Reversibility of monensin inhibition of oligosaccharide processing of human fibronectin

Monensin impairs oligosaccharide processing in fibronectin primarily by inhibiting the conversion of oligosaccharides from the high mannose type to the complex type. The separate effects of monensin and cations on alpha-mannosidase activity in fibroblasts were examined using an in vitro assay system. The results indicated that monensin did not directly inhibit alpha-mannosidase activity in vitro, although prior treatment of fibroblasts with monensin caused an irreversible suppression of enzyme activity. The reversibility of monensin action on oligosaccharide processing was also examined. Analyses using concanavalin A (ConA) Sepharose affinity chromatography showed that the inhibitory action of monensin on oligosaccharide processing was biologically reversible. A progressive return to complex type oligosaccharides began about 11 h after the removal of the monensin. These composite results indicate that the reversibility of monensin action on oligosaccharide processing in fibronectin may be attributed to the restoration of enzyme activity, although the mechanism by which restoration occurs remains to be deciphered.