苏云金芽孢杆菌cry基因在大肠杆菌中表达产物和生物活性

研究了几种Bt cry基因于大肠杆菌(Escherichia coli)中表达产物在pH 10.0的50mmol/L碳酸钠和20mmol/L乙醇胺溶解液中的溶解性 ,发现同样的Cry蛋白在碳酸钠中的溶解度大于乙醇胺。通过胰蛋白酶消化 ,明确Cry1Ca7、Cry1Ia8酶解产物为 38kD多肽 ;Cry1Ie1、Cry1Cb2、Cry2Ab4酶解产物为 41kD多肽 ;Cry1Ac酶解产物为60kD多肽。采用FPLC层析方法对 6种原毒素及其酶解后得到的毒素多肽进行了分离纯化 ,比较了原毒素和毒素的杀虫活性的差异。其结果表明 ,Cry1Ac的原毒素和毒素对棉铃虫初孵幼虫的校正死亡率均为 100% ,Cry2Ab4的原毒素的毒力高于其酶解毒素。     

电流处理抑制甘薯丛枝病症状及提高茎尖培养成苗率

甘薯丛枝病在我国东南沿海主薯区流行多年,发病率高,是影响我国甘薯产量和品质的一个主要限制因子。其典型症状是植株叶小、褪绿、矮缩和侧枝丛生。甘薯丛枝病病原物是一种类菌质体(Mycoplasma-like organism,MLO),现在国际上统称植原体(Phytoplasma)。     

羊肚菌研究进展

综述了近年来羊肚菌营养成分、有效成分，培养技术，以及细胞学、生物化学和分子生物学等方面的研究进展。     

Effect of heat shock precondition on reperfusion arrhythmia in rats

AIM:To investigate the effect of the heat shock response on the reperfusion arrhythmias(RAs) and the possible mechanism involved. METHODS:Fifty-five Sprague Dawley rats were randomly divided into 2 groups: the heat shock group (group H,n=29) and the control group (group C,n=26). The rats in group H were preconditioned with heat shock 24 hours before, and that in group C were not. The hearts of 16 rats in group H and 16 in group C were exercised and mounted on a non-circulating Langendorff perfusion apparatus and perfused retrogradely with modified K-H buffer and mimic ischemia/reperfusion was applied. Additionally, conventional intracellular microelectrode techniques were used for recording such electrophysiological parameters as resting potential(RP), action potential amplitude(APA), over shot(OS), maximum depolarization velocity(Vmax) of the hearts of other 13 rats in group H and 10 in group C. RESULTS:①Prior heat stress significantly decreased reperfusion arrhythmia. ②The amount of CK release in the effluent in group H was much less than that in group C. ③Myocardial HSP70 content was elevated significantly in group H. ④Heat stress significantly increased myocardial anti-oxydases activity and decreased lipid peroxydative products. Additionally, heat stress significantly reduced the Vmax of action potential. It indicated that rapid Na⁺ channel of papillary muscles may be inhibited by heat shock. The degree of change of Vmax after ischemia in H group was significantly less than that in group C. And the time of reperfusoin with Tyrode's solution till the action potential appeared as large as that before perfusion with mimic ischemic solution is shorter in group H than in group C. CONCLUSION:Heat shock pretreatment markedly reduces ischemia/reperfusion-induced injury of heart and ventricular arrhythmias in rats and this effect may be associated with the inhibition of rapid Na⁺ channel of papillary muscles by heat shock and the increase in myocardial HSP70 and anti-oxydase activity.     

Effect of lansoprazole on gastric ulceration in rats

AIM:To investigate the effect of lansoprazole on gastric ulceration in rats. METHODS:Using the gastric ulcer model induced by hemorrhagic shock, restraint water-immersion stress and pylorus-ligature, the protective effect of lansoprazole (iv) on gastric ulceration was observed. RESULTS:Pretreatment with lansoprazole (7.5-60 mg/kg) significantly inhibited the formation of gastric ulcer in the three models in a dose-dependent manner. The autiulcer efficacy of lansoprazole was similar to that of omeprazole in the equal dose, but stronger than that of omeprazole for ulcer induced by water-immersion stress.CONCLUSION:The intravenously administered lansoprazole inhibited formation of experimental gastric ulcer in rats.     

Se-containing spirulina phycocyanin attenuated liver injury induced by carbon tetrachloride in mice

AIM:To investigate the effect of Se-containing spirulina phycocyanin (Se-SPC) on liver injury of mice induced by carbon tetrachloride (CCl₄). METHODS:The mouse model was conducted by intragastric feeding with 2% CCl₄ oil for three times, meanwhile Se-SPC, spirulina phycocyanin (SPC) and Na₂SeO₃ were injected (ip) to various groups for 7 days. Then selenium (Se), glutathione peroxidase (GPx), superoxide dismutase (SOD), alanine aminotransferase (ALT), malondiaoldehyde (MDA) and nitric oxide (NO) levels in blood and liver were measured. RESULTS:The level of Se,GPx and SOD activities were obviously higher(P<0.05)but ALT activity,MDA and NO₂^-/NO₃^- levels were remarkably lower(P<0.05)in Se-SPC treated groups than those in CCl₄ groups,and effects of high dose Se-SPC on Se,GPx,MDA and NO₂^-/NO₃^- were even more significant(P<0.01).Under the same dose of Se or protein,effects of all selected targets in Se-SPC groups were more efficient than those in SPC groups and inorganic-Se groups.Furthermore,Se levels had a positive correlation with GPx activity(r=01705),which had negative correlation with levels of MDA,NO₂^-/NO₃^- and ALT(r=-0.629,r=-0.336,r=-0.457,respectively), and positive correlations between ALT activity and MDA or NO₂^-/NO₃^- level were found (r=0.519,r=0.641). CONCLUSION:These results indicated that Se-SPC may attenuate liver injury of mice induced by CCl₄ through its anti-inflammatory action and enhancing selenoenzyme expression.     

Effects of protein kinase C on modulation of vascular endothelium permeability

Protein kinase C pathway is an important intracellular signal transduction pathway. A growing number of evidences showes that activation of PKC influences endothelial cell permeability. In this review, we briefly summarize the effects and regulating pathways of protein kinase C in modulation of vascular endothelium permeability.     

Adult rat and human bone marrow mesenchymal stem cells differentiate into neurons with Musk's polypeptide

AIM: To investigate the differentiation from adult rat and human bone marrow mesenchymal stem cells (BMMSCs) into neuron with musk polypeptide (Mu-P).METHODS: Adult rat and human BMMSCs were induced with Mu-P.Neuron-specific enolase (NSE),neurofilament (NF),Nestin,glial fibrillary acidic protein (GFAP) were detected by immunohistochemistry.RESULTS: Simple methods with Mu-P induced adult rat and human BMMSCs exhibiting a neuronal phenotype,expressing Nestin at 3 hours to 5 hours,and expressing NE and NF at 5 hours to 7 days.But the neuron-like cells didn't express the glial astrocyte marker GFAP.CONCLUSION: Adult rat and human BMMSCs can be induced to differentiate into neurons with Mu-P.     

Effects of riboflavin and ascorbic acid on apoptosis and proliferative inhibition of mouse thymocytes induced by deoxynivalenol in vivo

AIM: To explore the effects of riboflavin and ascorbic acid on the apoptosis induced by deoxynivalenol(DON) in mouse thymocytes. METHODS: The effects of riboflavin and ascorbic acid on the apoptosis and proliferation inhibition of thymocytes induced by DON in KM mice were studied with animal experiment, DNA agarose gel electrophoresis and flow cytometric DNA content analysis. RESULTS: Apoptosis rate of thymocytes in DON (4 mg/kg) treated group was13.73%±15.3% The percentages of apoptosis in riboflavin (1.25 mg/kg-10mg/kg) and ascorbic acid (25 mg/kg-100mg/kg) pretreated thymocytes groups were significantly lower than that in DON group (P <0.05). The result of DNA agarose gel electrophoresis showed that the characteristic ladder pattern of apoptosis was found in DON-treated thymocytes, but not in control and riboflavin pretreatment and ascorbic acid pretreatment groups The significant differences in proliferation index were not found among DON-treated thymocytes and riboflavin and ascorbic acid-pretreated thymocytes CONCLUSION: Pretreatment with riboflavin and ascorbic acid inhibit apoptosis of mouse thymocytes induced by DON in certain extent and have no effect on proliferation inhibition by DON.     

The genetic susceptibility of HLA-DRB1 alleles in esophageal neoplasm of Hubei Han Chinese

AIM: To probe into the genetic susceptibility of HLA-DRB1 alleles to esophageal neoplasm in Hubei Han Chinese. METHODS: HLA-DRB1 gene polymorphism in 42 patients with esophageal neoplasm and 136 normal control subjects was studied by PCR and sequence. RESULTS: Allele frequency of HLA-DRB1 *0901 allele was significantly higher in esophageal cancer patients than those in normal controls(0.2500 vs 0.1397, P =0.028; the odds ratiO².053; etiologic fraction 0.1282).There were no association between the rested HLA-DRB1 alleles with patients. CONCLUSION: Individuals carrying HLA-DRB1 *0901 may be susceptible to esophagealo carcinoma, its nucleotide sepuence approachs to the corresponded allele sequence(exoN²)published in GenBank.