Molecular Cloning of Two Novel Temporins From Lithobates catesbeianus and Studying of Their Antimicrobial Mechanisms / 生物化学与生物物理进展

Temporins are a kind of small,hydrophobic and C-terminus amidated antimicrobial peptides from Rana species.They are effective against bacteria,fungi,yeast,protozoa and viruses.Two novel temporins named as temporin-La(LLRHWKILEKYLanifc) and temporin-Lb(LFRHVVKIFEK.Ylamid.) were cloned from Lithobates catesbeianus.Synthetic peptides of temporin-La and temporin-Lb showed strong antimicrobial activities against bacteria tested,especially Gram-positive bacteria.Besides,temporin-La showed no haemolytic activity to rabbit erythrocytes at the concentration of 250 mg/L while temporin-Lb showed weak haemolytic activity(LC50≈ 230 μmol/L).Transmission electron microscopy showed that temporin-La and temporin-Lb induced different effects on bacterial structure of Staphylococcus aureus.

Antibiotic Sensitivity Detection and Analysis of Escherichia coli Isolated Clinically in China / 中国兽医学报

The susceptibility to 9 kinds of antibiotics of 393 animal pathogenic E. coli isolated from clinical samples was determined from 2000 to 2003. The resistance to TC, GM, CMP, AMP, RA, KM, FT, SM and CIP were 93.89%, 57.76%,78.63%, 77.86%, 92.11% ,47.33%, 46.82%, 76.84% and 74.81%, respectively. The isolates could be classified into eight classes according to the number of drugs to which srains were resistant. The resistance spectrum of the isolates varied from 2to 9 kinds of the above drugs. The strains that were resistant to seven kinds of drugs were more than 80 percent. The resistance rates of swine origin strains to GM,AMP and KM were higher than those of poultry origin strains, while the resistance rates of poultry origin strains to TC, CMP, SM and CIP were higher remarkably than those of swine origins. The frequency of resistance increased from 2000 to 2003,which was from 67.33% to 90.58% for CMP, 71.29% to 84.81% for AMP, 73.76%to 80.10% for SM and 61.88% to 88.48% for CIP. At the same time, the resistance rate of GM decreased from 61.39% to 53.92%. Thirty-seven strains (95 %) could make all the Kunming mice die within 72 h injected intraperitoneally with the culmice three times in vivo. The pathogenicity of wild strains with drug resistance acquired naturaly to mice did not decline.

The effect of OX-LDL and simvastatin on PKC activity and cytosolic free Ca 2+ in cultured human monocytes / 中国药理学通报

AIM　To investigate the effect of OX-LDL and HMG- CoA reductase inhibitors simvastatin on PKC activity and cytosolic free Ca2+ in cultured human monocy tes. METHOD　The activity of PKC was determined by its ability to tr ansfer phosphate from ［32P］ATP to lysine-rich histone and cytosolic free calcium［Ca2+］i was measured by flow cytometric analysis loading with the Ca2+ dye fluo3/Am. RESULTS　OX-LDL increased PKC tot al activity in a dose-dependent manner with phase peaking at 12 min, then decre ased slowly and maintained for at least 20 min, while OX-LDL induced biphasic ［Ca2+］i responses including the rapid initial transient phase and the sustained phase. Removal of extracellular Ca2+ did not inhibit the rapid i nitial transient phase of OX-LDL-induced rise in ［Ca2+］i,but abolish ed the sustained phase of ［Ca2+］i response to OX-LDL. When simvastati n was added, the activity of PKC was markedly decreased and simvastatin did not impair the initial peak response to OX-LDL but significantly reduced the subseq uent plateau phase. CONCLUSION OX-LDL can significantly activate t he activity of PKC and elevate ［Ca2+］i in monocytes. The rapid initial transient phase was the result of mobilization of ［Ca2+］i from intrac ellular pool and sustained phase resulted from the influx of extracellular Ca 2+. The inhibition of PKC activity induced by simvastatin may be contribute to the changes of intracellular Ca2+.

Effects of oxLDL and simvastatin on PKC activity and level of cytosolic free Ca 2+ in cultured human umbilical vein endothelial cells / 第二军医大学学报

Objective: To investigate the effects of oxLDL and HMG-CoA reductase inhibitor simvastatin on PKC activity, and level of cytosol ic free Ca 2+ in cultured human umbilical vein endothelial cells. Methods: Th e activity of PKC was determined by its ability to transfer phosphate from 32P-ATP to lysine-rich histone and level of cytosolic free calcium［Ca2+ ］i was measured by flow cytometric analysis loading with the Ca2+ dye F luo-3/Am. Results: oxLDL increased PKC total activity in a dose-de pendent manner and peaked after 12 min, then decreased slowly and maintained for at least 30 min, while oxLDL induced biphasic ［Ca2+］i responses includ ing the rapid initial transient phase and the sustained phase. Removal of extrac ellular Ca2+ did not inhibit the rapid transient phase, but abolished the sustained phase. When simvastatin was added, the activity of PKC wasmarkedly dec reased with no impairment to the initial peak response, but significantly reduce d the sustained phase. Conclusion: oxLDL can induced dynamic changes of signal transduction of PKC and level of cytosolic free Ca2+ in HUVEC, these 2 events are closely linked. The change of rapid initial transient phase i s the result of mobilization of Ca2+ from intracellular pool and the chang e of sustained phase is from the influx of extracellular Ca2+. The inhibit ion of PKC activity induced by simvastatin may contribute to the changes of ［Ca 2+］i.

Effects of oxidized low density lipoprotein and vitamin E on the levels of IL-6,IL-8 and TNF-? in cultured human umbilical vein endothelial cells / 中国病理生理杂志

AIM: To investigate effects of OX-LDL and VitE on the levels of IL-6,IL-8 and TNF-? in human umbilical vein endothelial cells(HUVEC). METHODS: Human umbilical vein endothelial cells were obtained by in vitro culture. HUVEC treated with or without Vit E was incubated with OX-LDL, and the levels of IL-6, IL-8 and TNF-? were determined by enzyme-linked immunosorbent assy technique. RESULTS:50 ?g/L,100 ?g/L, 200 ?g/L OX-LDL induced the release of IL-6,IL-8 and TNF-? by HUVEC in a dose-dependent manner. Compared with the control group , the levels of IL-6 and IL-8 were significantly increased at 6-12 h of stimulation with OX-LDL . Maximal levels of IL-6 and IL-8 occurred after 24-36 h, reaching a plateau maintained for at least 48 h. TNF-? rose after 2-6 h in HUVEC, and reached a maximum after 12 h. In contrast to IL-6 and IL-8, TNF-? declined after 48 h. However, when VitE (50 mg/L,100 mg/L,200 mg/L)was added, it can significant inhibited the release of IL-6, IL-8 and TNF-? in a dose-dependent manner, and after 48 h these cytokines have no diference between OX-LDL+VitE groups and OX-LDL groups. CONCLUSION: OX-LDL can obviously stimulate the production of IL-6,IL-8 and TNF-? in vascular endothelial cells, which can significantly be inhibited by VitE in a short time.

The effect of OX-LDL and simvastatin on PKC activity and cytosolic free Ca~(2+) in cultured human monocytes / 中国药理学通报

AIM To investigate the effect of OX- LDL and HMG-CoA reductase inhibitors simvastatin on PKC activity and cytosolic free Ca2+ in cultured human monocytes. METHOD The activity of PKC was determined by its ability to transfer phosphate fm [32P] ATP to lysine-rich histone and cytosolic free calcium[Ca2+]i was measured by flow cytometric analysis loading with the Ca2+ dye fluo3/Am.RE- SULTS OX-LDL increased PKC total activity in a dose-dependent manner with phase peaking at 12 min, then decreased slowly and maintained for at least 20 min, while OX-LDL induced biphasic [Ca2+ ], responses including the rapid initial transient phase and the sustained phase. Removal of extracellular Ca2+ did not inhibit the rapid initial transient phase of OX-LDL-induced rise. in [ Ca2+ ]i, but abol- abolished the sustained phase of [ Ca2+ ] i response to OX LDL. When simvastatin was added, the activity of PKC was markedly decreased and simvastatin did not impair the initial peak response to OX-LDL but sig- nificantly reduced the subsequent plateau phase. CONCLUSION OX-LDL can significantly activate the activity of PKC and elevate [Ca2+ ]i in monocytes. The rapid initial transient phase was the result of mobilization of [Ca2+ ], fm intracellular pool and sustained phase resulted from the influx of extracellular Ca2+. The inhibition of PKC activity induced by simvastatin may be contribute to the changes of intracellular Ca2+.

Effect of OX-LDL and simvastatin on PKC activity and cytosolic free Ca~(2+) in cultured rat aortic smooth muscle cells / 中国病理生理杂志

AMI: To clarify whether OX-LDL and simvastatin can induce the changes of PKC activity and cytosolic free Ca 2+ in rat aortic smooth muscle cells (ASMC). METHODS: PKC activity and cytosolic free Ca 2+ were measured by its ability to transfer phosphate from ATP to lysine-rich histone and flow cytometric analysis after loading with the Ca 2+ dye fluo 3/Am, respectively. RESULTS: OX-LDL increased PKC total activity in a dose-dependent manner and induced translocation of PKC from the cytosolic to membrane, while OX-LDL induced biphasic [Ca 2+ ]i responses including the rapid initial transient phase and the sustained phase. When simvastatin was added, the translocation of PKC was markedly decreased and simvastatin did not impair the initial peak response to OX-LDL but significantly reduced the subsequent plateau phase. CONCLUSSION: OX-LDL can induce dynamic changes of signal transduction of PKC and cytosolic free Ca 2+ in ASMC and these two events are closely linked.

Effects of oxLDL and simvastatin on PKC activity and level of cytosolic free Ca~(2+) in cultured human umbilical vein endothelial cells / 第二军医大学学报

Objective: To investigate the effects of oxLDL and HMG CoA reductase inhibitor simvastatin on PKC activity, and level of cytosolic free Ca 2+ in cultured human umbilical vein endothelial cells. Methods: The activity of PKC was determined by its ability to transfer phosphate from 32 P ATP to lysine rich histone and level of cytosolic free calcium[Ca 2+ ]i was measured by flow cytometric analysis loading with the Ca 2+ dye Fluo 3/Am. Results: oxLDL increased PKC total activity in a dose dependent manner and peaked after 12 min, then decreased slowly and maintained for at least 30 min, while oxLDL induced biphasic [Ca 2+ ]i responses including the rapid initial transient phase and the sustained phase. Removal of extracellular Ca 2+ did not inhibit the rapid transient phase, but abolished the sustained phase. When simvastatin was added, the activity of PKC wasmarkedly decreased with no impairment to the initial peak response, but significantly reduced the sustained phase. Conclusion: oxLDL can induced dynamic changes of signal transduction of PKC and level of cytosolic free Ca 2+ in HUVEC, these 2 events are closely linked. The change of rapid initial transient phase is the result of mobilization of Ca 2+ from intracellular pool and the change of sustained phase is from the influx of extracellular Ca 2+ . The inhibition of PKC activity induced by simvastatin may contribute to the changes of [Ca 2+ ]i. [