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排序方式: 共有153条查询结果,搜索用时 15 毫秒
1.
Anaphylactic reaction associated with Ranitidine in a patient with acute pancreatitis: a case report
Sustained chronic tachyarrhythmias often cause a deterioration of cardiac function known as tachycardia-induced cardiomyopathy or tachycardiomyopathy. The incidence of tachycardia-induced cardiomyopathy is unknown, but in selected studies of patients with atrial fibrillation, approximately 25% to 50% of those with left ventricular dysfunction had some degree of tachycardia-induced cardiomyopathy. It is an important clinical entity due to the high incidence and potential reversibility of the disease process. This case describes a cardiomyopathy induced by excess caffeine consumption. Six months following withdrawal of caffeine from the subject's diet, full resolution of symptoms occurred. 相似文献
2.
We have studied the effects of two polyamine biosynthetic inhibitors, alpha-difluoromethylornithine (DFMO) and alpha-difluoromethylarginine (DFMA), and of polyamines (PAs), alone and in combination, on mycelial growth and morphology of four phytopathogenic fungi: Botrytis sp, B. cinerea, Rhizoctonia solani and Monilinia fructicola. The inhibitors were added to a Czapek agar medium to get final concentrations of 0.1, 0.5 and 1.0 mM. DFMO and DFMA, suicide inhibitors of ornithine decarboxylase (ODC) and arginine decarboxylase (ADC) respectively, inhibited mycelial growth strongly; the effect was generally more pronounced with DFMA than with DFMO, but each fungus had its own response pattern. The addition of the PAs putrescine (Put) and spermidine (Spd) to the culture medium resulted in a promotion of growth. In Botrytis sp and Monilinia fructicola exposed to inhibitors plus PAs, mycelial growth was actually increased above control values. Mycelial morphology was altered and cell size dramatically reduced in plates containing inhibitors alone, whereas with PAs alone, or in combination with inhibitors, morphology was normal, but cell length and diameters increased considerably. These results suggest that PAs are essential for growth in fungal mycelia. The inhibition caused by DFMA may be due to its arginase-mediated conversion to DFMO. 相似文献
3.
Polyamine Accumulation and Near Loss of Morphogenesis in Long-Term Callus Cultures of Rice (Restoration of Plant Regeneration by Manipulation of Cellular Polyamine Levels) 总被引:3,自引:0,他引:3 下载免费PDF全文
We have shown (S. Bajaj and M.V. Rajam [1995] Plant Cell Rep 14: 717-720) that a significant reduction in morphogenetic potential occurs in callus cultures of rice (Oryza sativa L. cv TN-1) (up to 1 year old), and that plant regeneration could be improved in such cultures with spermidine treatment. We now show a near loss in plant regeneration capacity, concomitant with massive polyamine accumulation (primarily the diamine putrescine), due to the increase in arginine decarboxylase activity and an altered putrescine-to-spermidine ratio in 20- and 36-month-old rice callus cultures. The blockage of polyamine accumulation due to the reduction in arginine decarboxylase activity by a putrescine synthesis inhibitor, [alpha]-difluoromethylarginine, completely restored plant regeneration capacity in these long-term cultures. Additionally, spermidine treatment of long-term cultures caused an increase in cellular spermidine content and a reduction in putrescine content and arginine decarboxylase activity, leading to an adjustment in putrescine-to-spermidine ratio and the restoration of plant regeneration ability. 相似文献
4.
Polyamine (PA) biosynthesis inhibitors, difluoromethylornithine (DFMO), difluoromethylarginine (DFMA), methylglyoxal bis-(guanylhydrazone) (MGBG) and bis-(cyclohexylammonium) sulphate (BCHA) have been tested for their effects on colony diameters at different intervals after inoculation of four plant pathogenic fungi (Helminthosporium oryzae, Curvularia lunata, Pythium aphanidermatum and Colletotrichum capsici). All these inhibitors, except DFMA had strongly retarded the growth of four fungi in a dose- and species-dependent fashion, and H. oryzae and C. lunata were found to be most sensitive to the effects of PA inhibitors. P. aphanidermatum and C. capsici were relatively insensitive and required rather high concentrations of inhibitors to get greater inhibition of mycelial growth, except DFMA which had stimulatory effect on the growth of these two fungi. However DFMA had greatly suppressed the growth of H. oryzae and C. lunata. The effect was generally more pronounced with MGBG than with DFMO and BCHA, and 1 mM Put completely prevented the inhibitory effects of 1 and 5 mM DFMO. Analysis of free and conjugated PAs in two sensitive fungi (H. oryzae and C. lunata) revealed that Put was present in highest concentrations followed by Spd and Spm and their levels were greatly reduced by DFMO application, and such inhibitions were totally reversed by exogenously supplied Put; in fact, PA titers were considerably increased by 1 mM Put alone and in combination with 1 mM DFMO. These results suggest that PA inhibitors, particularly DFMO and MGBG may be useful as target-specific fungicides in plants. 相似文献
5.
A protocol has been developed to obtain whole plants from apical shoot meristems of red pepper (Capsicum annuum L. cv. Bhivapuri), susceptible to viral infections. The meristems (~ 0.8 mm long), from aseptically grown seedlings (one-month-old), cultured on filter paper bridge in liquid Murashige and Skoog medium supplemented with 2 mg/l benzylaminopurine produced multiple shoots (5–7 per explant). The differentiated shoots developed further upon transfer to agar-solidified medium. Complete plantlets were obtained after rooting of shoots on MS medium fortified with 1 mg/l naphthaleneacetic acid. 相似文献
6.
Computational methods have played a key role in elucidating the various three-dimensional structures of oligosaccharides. Such structural information, together with other experimental data, leads to a better understanding of the role of oligosaccharide in various biological processes. The disialoside Neu5Ac-alpha2-->8-Neu5Ac appears as the terminal glycan in glycoproteins and glycolipids, and is known to play an important role in various events of cellular communication. Neurotoxins such as botulinum and tetanus require Neu5Ac-alpha2 --> 8-Neu5Ac for infecting the host. Glycoconjugates containing this disialoside and the enzymes catalyzing their biosynthesis are also regulated during cell growth, development, and differentiation. Unlike other biologically relevant disaccharides that have only two linkage bonds, the alpha2-->8-linked disialoside has four: C2-O, O-C8', C8'-C7', and C7'-C6'. The present report describes the results from nine 1 ns MD simulations of alpha2-->8-linked disialoside (Neu5Ac-alpha2-->8-Neu5Ac); simulations were run using GROMOS96 by explicitly considering the solvent molecules. Conformations around the O-C8' bond are restricted to the +sc/+ap regions due to stereochemical reasons. In contrast, conformations around the C2-O and C8'-C7' bonds were found to be largely unrestricted and all the three staggered regions are accessible. The conformations around the C7'-C6' bond were found to be in either the -sc or the anti region. These results are in excellent agreement with the available NMR and potential energy calculation studies. Overall, the disaccharide is flexible and adopts mainly two ensembles of conformations differing in the conformation around the C7'-C6' bond. The flexibility associated with this disaccharide allows for better optimization of intermolecular contacts while binding to proteins and this may partially compensate for the loss of conformational entropy that may be incurred due to disaccharide's flexibility. 相似文献
7.
Clinical decision is often difficult with chlorhexidine mouthwash. The use of antioxidant mouthwashes for the treatment of periodontal disease is in practise. Therefore, it is of interest to collect gleaned information on Antioxidant mouthwashes as periodontal therapy from known literature. Improvement in treatment using antioxidant mouthwashes is reported in several studies. The mouthwash with antioxidants has similar anti-gingivitis, antiplaque and antimicrobial effects as that of chlorhexidine mouthwash. 相似文献
8.
Choudhury Aparajita Verma Shubham Muthamilarasan Mehanathan Rajam Manchikatla Venkat 《Molecular biology reports》2021,48(11):7477-7485
Molecular Biology Reports - Maruca vitrata is one of the potential insect pests that cause devastating losses to legume cultivation worldwide. Gene functional studies facilitate dissecting the... 相似文献
9.
Alexey Vorobev Sheeja Jagadevan Bipin S. Baral Alan A. DiSpirito Brittani C. Freemeier Brandt H. Bergman Nathan L. Bandow Jeremy D. Semrau 《Applied and environmental microbiology》2013,79(19):5918-5926
Many methanotrophs have been shown to synthesize methanobactin, a novel biogenic copper-chelating agent or chalkophore. Methanobactin binds copper via two heterocyclic rings with associated enethiol groups. The structure of methanobactin suggests that it can bind other metals, including mercury. Here we report that methanobactin from Methylosinus trichosporium OB3b does indeed bind mercury when added as HgCl2 and, in doing so, reduced toxicity associated with Hg(II) for both Alphaproteobacteria methanotrophs, including M. trichosporium OB3b, M. trichosporium OB3b ΔmbnA (a mutant defective in methanobactin production), and Methylocystis sp. strain SB2, and a
Gammaproteobacteria methanotroph, Methylomicrobium album BG8. Mercury binding by methanobactin was evident in both the presence and absence of copper, despite the fact that methanobactin had a much higher affinity for copper due to the rapid and irreversible binding of mercury by methanobactin. The formation of a gray precipitate suggested that Hg(II), after being bound by methanobactin, was reduced to Hg(0) but was not volatilized. Rather, mercury remained associated with methanobactin and was also found associated with methanotrophic biomass. It thus appears that although the mercury-methanobactin complex was cell associated, mercury was not removed from methanobactin. The amount of biomass-associated mercury in the presence of methanobactin from M. trichosporium OB3b was greatest for M. trichosporium wild-type strain OB3b and the ΔmbnA mutant and least for M. album BG8, suggesting that methanotrophs may have selective methanobactin uptake systems that may be based on TonB-dependent transporters but that such uptake systems exhibit a degree of infidelity. 相似文献
10.
Bela M Arosalo Marja Raekallio Minna Rajamäki Elina Holopainen Tuulia Kastevaara Hanna Salonen Satu Sankari 《Acta veterinaria Scandinavica》2007,49(1):4