RESUMO
Six new tirucallane-type triterpenoids (1-6), along with ten known triterpenoids, were isolated from methylene chloride extract of the resin of Boswellia carterii Birdw. By the application of the comprehensive spectroscopic data, the structures of the compounds were clarified. The experimental electronic circular dichroism spectra were compared with those calculated, which allowed to assign the absolute configurations. Compounds 5 and 6 possesed a 2, 3-seco tirucallane-type triterpenoid skeleton, which were first reported. Their inhibitory activity against NO formation in LPS-activated BV-2 cells were evaluated. Compound 9 showed appreciable inhibitory effect, with an IC
RESUMO
Venous leg ulcer (VLU) is the most common chronic ulcer of lower extremity caused by persistent venous hypertension. Although the mortality rate is low, VLU seriously affects the quality of life of patients, and has the potential for infection, deterioration, and amputation. The compression therapy is simple and easy to implement, it can effectively reduce venous hypertension and is the most important conservative therapy for treating and preventing recurrence of VLU. There are various devices and applications of compression therapy, and this article reviews the classification of compression therapy, and its application in treatment and recurrence prevention of VLU.
RESUMO
Over the years, culturable cellulase-producing microorganisms have been isolated from a variety of sources and genes of cellulolytic enzymes have been cloned. Then again, the "great plate count anomaly" phenomenon necessitates a culture-independent metagenomic approach for the isolation of cellulolytic genes from microorganisms in their natural environment. We have constructed a metagenomic library derived from rice straw composts. Of 2739 clones screened, a lambda clone carrying a 12kb genomic fragment was able to yield a clear zone on an agar plate containing carboxymethyl cellulose (CMC). A 4.7kb subclone, generated by restriction enzyme digestion, was found to harbor a GH12 cellulase gene, RSC-EG1, encoding 464 amino acids along with two other ORFs. The identified cellulolytic gene showed more than 70% similarity on the amino acid level with cellulase from Micromonospora aurantiaca and Thermobispora sp. Interestingly, RSC-EG1 contains a stretch of approximately 86 amino acids not present in either of these close relatives. Our results demonstrated that RSC-EG1, stable over a wide temperature and pH range, is a novel endoglucanase, and provided the first example of metagenomics approach to isolate cellulolytic gene from rice straw composts.
