Hirudin, the most potent inhibitor of thrombin found in nature, has a short half-life in serum, which sig-nificantly limits its clinical application as an anticoagulant. Recently, PEGylation has been commonly used as ...Hirudin, the most potent inhibitor of thrombin found in nature, has a short half-life in serum, which sig-nificantly limits its clinical application as an anticoagulant. Recently, PEGylation has been commonly used as an effective method to prolong its half-life in serum. In contrast to the nonspecific pEGylation under basic conditions that targets lysine residues randomly, PEGylation sites under mildly acidic conditions preferably targets histidine residues, and there is only one histidine residue at 51 in r-hirudin; therefore, succinimidyl carbonyl methoxy poly-ethylene glycol （SC-mPEG, 20000） was attached to r-hirudin at mildly acidic pH to favor the formation of mono-PEGylated r-hirudin. The reaction mixture with high mono-PEGylated ratio was easily separated by a one-step ion-exchange chromatographic （IEC） procedure. Approximately 79.71% of the mono-PEGylated r-hirudin was PEGylated at His51, which showed that the acidic PEGylation operation prevented the PEGylation of active center （Lys47） of r-hirudin in pdnciple. Mono-PEGylated.product with purity higher than. 95% was obtained as the pre-dominant product, and 34% of the anticoagulant activity was retained in vitro. The staining method for sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE） was improved to obtain perfect electrophoretic pattern in less than 5min. More accurate molecular weight was deduced due to the use of PEGs as molecular weight standards.展开更多
Sesamum, an important oil yielding crop suffers a huge loss in its yield due to attack of large number of fungal pathogens. In semi-arid regions Sesamum is mainly affected by two major plant-pathogenic fungus viz. Mac...Sesamum, an important oil yielding crop suffers a huge loss in its yield due to attack of large number of fungal pathogens. In semi-arid regions Sesamum is mainly affected by two major plant-pathogenic fungus viz. Macrophomina phaseolina and Fusarium oxysporum. The aim of the study was to analyze the metabolic alterations in Sesamum after infection with both pathogens. This accomplished by individually by （the word estimating is not quantitative） the levels of total phenolic compounds and the activities of phenylalanine ammonia lyase （PAL） of one week old plants. The PAL showed high activity in infected plants, revealing the active phase in the synthesis of secondary metabolites in the Sesamum plant after infection. As a consequence, in infected plants the contents of polyphenols along with salicylic acid （SA） considerably exceeded when compared to control plants. This in vivo study of M. phaseolina and F. oxysporum infection reveals the differences of resistance levels in sesame against these two pathogens. These results provide important information regarding the plant-pathogen interactions and also forfor Sesamum improvement programs seeking the adaptation to diverse range of fungal attack along with adverse environmental factors.展开更多
文摘Hirudin, the most potent inhibitor of thrombin found in nature, has a short half-life in serum, which sig-nificantly limits its clinical application as an anticoagulant. Recently, PEGylation has been commonly used as an effective method to prolong its half-life in serum. In contrast to the nonspecific pEGylation under basic conditions that targets lysine residues randomly, PEGylation sites under mildly acidic conditions preferably targets histidine residues, and there is only one histidine residue at 51 in r-hirudin; therefore, succinimidyl carbonyl methoxy poly-ethylene glycol （SC-mPEG, 20000） was attached to r-hirudin at mildly acidic pH to favor the formation of mono-PEGylated r-hirudin. The reaction mixture with high mono-PEGylated ratio was easily separated by a one-step ion-exchange chromatographic （IEC） procedure. Approximately 79.71% of the mono-PEGylated r-hirudin was PEGylated at His51, which showed that the acidic PEGylation operation prevented the PEGylation of active center （Lys47） of r-hirudin in pdnciple. Mono-PEGylated.product with purity higher than. 95% was obtained as the pre-dominant product, and 34% of the anticoagulant activity was retained in vitro. The staining method for sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE） was improved to obtain perfect electrophoretic pattern in less than 5min. More accurate molecular weight was deduced due to the use of PEGs as molecular weight standards.
文摘Sesamum, an important oil yielding crop suffers a huge loss in its yield due to attack of large number of fungal pathogens. In semi-arid regions Sesamum is mainly affected by two major plant-pathogenic fungus viz. Macrophomina phaseolina and Fusarium oxysporum. The aim of the study was to analyze the metabolic alterations in Sesamum after infection with both pathogens. This accomplished by individually by （the word estimating is not quantitative） the levels of total phenolic compounds and the activities of phenylalanine ammonia lyase （PAL） of one week old plants. The PAL showed high activity in infected plants, revealing the active phase in the synthesis of secondary metabolites in the Sesamum plant after infection. As a consequence, in infected plants the contents of polyphenols along with salicylic acid （SA） considerably exceeded when compared to control plants. This in vivo study of M. phaseolina and F. oxysporum infection reveals the differences of resistance levels in sesame against these two pathogens. These results provide important information regarding the plant-pathogen interactions and also forfor Sesamum improvement programs seeking the adaptation to diverse range of fungal attack along with adverse environmental factors.
