Research progress of new antibacterial drugs that target bacterial quorum sensing systems / 药学学报

In recent years, antibiotic resistance of bacteria has become a global health crisis. Especially, the new class of "superbug" was found in South Asia, which is resistant to almost known antibiotics and causes worldwide alarm. Through the underlying mechanisms of bacterial pathogenecity, the expression of many pathogen virulence factors is regulated by the process of quorum sensing. Screening efficient quorum sensing inhibitors is an especially compelling approach to the future treatment of bacterial infections and antibiotic resistance. This article focuses on bacterial quorum sensing system, quorum sensing screening model for in vitro and evaluation of animal models in vivo, recent research of quorum sensing inhibitors and so on.

Isolation and Identification of Marine Actinomycetes with Quorum Sensing Inhibitory Activity / 微生物学通报

Quorum sensing systems of pathogens are central regulators for the expression of virulence factors. Increasing evidence implies that targeting the quorum sensing system of many pathogenic bacteria is a promising therapeutic approach to control infections. In this work,we isolated 47 strains of actinomycetes from the mud sample of Jiaozhou Bay. Quorum sensing inhibitory activity was monitored by Chromobacterium violaceum CV026. As a result,the culture broth extract of actinomycetes WA-7 was found to have significant quorum sensing inhibitory activity. This strain was assigned to the genus Streptomyces based on its 16S rDNA sequence. Further investigation revealed that the extract could inhibit the quorum sensing-controlled violacein and proteases production of C. violaceum in a concentration-dependent manner.

Inhibition of MCP-1 mRNA expression by propylene glycol mannate sulfate in hyperlipidemic rat aorta / 药学学报

<p><b>AIM</b>To study the effects of prophylene glycol mannate sulfate (PGMS) on monocyte chemoattractant protein-1 (MCP-1) mRNA expression in hyperlipidemic rat aorta and to clarify the molecular mechanism of PGMS for the prevention of atherosclerosis.</p><p><b>METHODS</b>PGMS (37.8 and 75.6 mg.kg-1.d-1, ig) or PGMS (37.8 and 75.6 mg.kg-1.d-1, ig) combined with diethyldithiocarbamate (DDC, an inhibitor of SOD, 200 mg.kg-1 every three days, i.p.) were given to hyperlipidemic rats for three weeks. The MDA content and SOD activity were determined after 12 h of starvation, and MCP-1 mRNA expression in aorta was detected by reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>There was significant decrease (29.46% or 58.40)% of MCP-1 mRNA expression in aortic after the therapy. The SOD activity increased markedly and the MDA content decreased at the same time. After treatment with DDC, the SOD activity was inhibited and the MDA content increased, but with no significant effect on MCP-1 mRNA expression.</p><p><b>CONCLUSION</b>PGMS inhibited MCP-1 mRNA expression with no relation to its effect on decreasing MDA content.</p>

Effect of propylene glycol mannate sulfate on blood lipids and lipoprotein lipase in hyperlipidemic rat / 药学学报

<p><b>AIM</b>To study the effect of propylene glycol mannate sulfate (PGMS) on blood lipids and lipoprotein lipase in hyperlipidemic rat, and its anti-hyperlipidemic mechanism.</p><p><b>METHODS</b>PGMS was administered ig at different doses (37.8 mg.kg-1.d-1 and 75.6 mg.kg-1.d-1) to hyperlipidemic rats for three weeks and blood serum was obtained after starved 12 h. Total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) were examined. The mRNA expression of lipoprotein lipase (LPL) in liver, spleen and artery was detected by reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>PGMS significantly decreased the levels of TC, TG and LDL-C and increased that of HDL-C in hyperlipidemic serum dose-dependently. PGMS was shown to increase the level of LPL mRNA expression, which is related directly to the controlling effects of PGMS on blood lipids.</p><p><b>CONCLUSION</b>PGMS modulated blood lipids by promoting mRNA expression of LPL. This may be one important mechanism of PGMS to modulate blood lipids.</p>

Induction of CuZn-SOD mRNA expression and activity by PGMS in rat liver / 药学学报

<p><b>AIM</b>To study the effect of propylene glycol mannate sulfate (PGMS) on induction of CuZn-SOD.</p><p><b>METHODS</b>Wistar rats were given PGMS p.o. at different doses (0, 18.9, 37.8 and 75.6 mg.kg-1.d) for ten days. Then the rats were sacrificed and the total RNA was extracted from the livers. The total RNA samples were loaded on a 1% agarose gel to detect the quality of total RNA. RT-PCR was applied to study the expression of CuZn-SOD mRNA in rat livers. The amplified products were detected by the 1.5% agarose gel electrophoresis. Simultaneously, the CuZn-SOD activities in rat liver were determined by nitrite method.</p><p><b>RESULTS</b>The total RNA extracted from rat livers was integrated without being decomposed by RNase. The level of CuZn-SOD mRNA of the high-dosage group (75.6 mg.kg-1.d) was higher than that of the control group (0 mg.kg-1.d) (P < 0.01); the CuZn-SOD activities of the high-dosage group were significantly higher than those of the control group (P < 0.001) and the CuZn-SOD activities of the middle- (37.8 mg.kg-1.d) and low-dosage groups (18.9 mg.kg-1.d) were higher than those of the control group (P < 0.01).</p><p><b>CONCLUSION</b>PGMS can increase the CuZn-SOD activities as well as CuZn-SOD on mRNA level. Therefore, it is possible for PGMS to counteract Atherosclerosis (AS) by inducing the expression of CuZn-SOD.</p>