灰葡萄孢菌nit突变体的诱导及其在营养体亲和性测定中的应用初探

 从山西运城、临汾、长治、晋中、大同等地保护地黄瓜灰霉病病株上采集、分离的分属于3个不同菌丝融合群的8个灰葡萄孢菌单孢菌株,经氯酸盐诱导处理,共获得了抗氯酸盐的硝酸盐利用缺陷突变体(nit突变体)59株,其中nit1型38株,nit3型10株,nitM型11株。所有nit突变株分别在PDA斜面转管培养3次(21 d)后,除6株恢复成野生菌株外,其余多数nit突变菌株表现稳定。来源于同一野生菌株的不同类型nit突变体间或同一菌丝融合群不同野生菌株的nit突变体间可产生互补反应而形成异核体,其中以nitM型突变株互补性最好,在利用nit突变体测定灰葡萄孢菌营养体亲和性时应作为标准菌株。来源于不同菌丝融合群的nit突变体间不能产生互补反应。     

猕猴桃果实成熟前补钙对果实含钙量的影响

猕猴桃果实成熟前用喷叶法和喷果法补钙，可显著提高果实中的钙含量。喷叶较喷果效果好。用Ca(NO3)2喷叶，比用CaCl2处理效果好，差异显著。而果实对CaCl2和Ca(NO3)2的吸收选择性差异不显著。经补钙处理的果实采后进行贮藏效果观察发现：用Ca(NO3)2喷叶处理的果实贮藏性较好，用其喷果处理次之；用CaCl2喷果和喷叶处理的果实贮至28天软果率均达到90％。     

铺散诸葛菜的组织培养及植株再生

 以铺散诸葛菜的叶柄及叶片为外植体, 研究了不同的再生方式。在6-BA 和NAA 配合使用的MS 培养基上, 叶柄和叶片外植体有高的成芽率, 具有强的器官再生能力。在2,4-D 与6-BA、NAA 结合的培养基上, 叶柄和叶片有较高的愈伤组织诱导率, 在含6-BA 的培养基上也易于分化。叶柄、叶片再生的芽和经愈伤组织分化而得来的芽快速繁殖后, 在生根培养基上形成完整植株。研究表明铺散诸葛菜具有极强的器官分化能力。     

世界葡萄抗寒育种的成就与展望

近2个世纪,通过选种和杂交育种,世界葡萄抗寒育种在抗寒性与果实优质性状的结合方面取得了突破,育成许多抗寒性极强(耐-30～-40℃低温)、品质优良的鲜食、酿酒和制汁品种。由于葡萄的抗寒性是受多基因控制的数量性状,杂交后代的抗寒性基本呈以亲中值为峰顶的正态分布,所以我国应积极引进这些品种,在华北、西北等葡萄主产区试验、推广露地越冬栽培的同时,利用它们与现有抗寒性较弱的主栽品种(抗寒性-15～-18℃)杂交,培育适合我国冬季气候条件的抗寒品种(抗寒性在-25℃左右),迅速提高我国葡萄抗寒育种水平。     

Role of vascular remolding induced by nitric oxide and matrix metalloproteinase in aneurysm

Nitric oxide (NO) and matrix metalloproteinases (MMPs) are important in vascular remolding, especially in abdominal aortic aneurysm. NO may be associated with aneurysms by modulating MMPs expression and activity.     

Nitric oxide-mediated the cardioprotection of tumor necrosis factor-alpha on cultured neonatal rat cardiomyocytes during hypoxia/reoxygenation

AIM: To investigate the role of nitric oxide synthase (NOS), soluble guanylyl cyclase (sGC) and protein kinase C (PKC) signaling in tumor necrosis factor-α (TNF-α)-induced cardioprotection against hypoxia/reoxygenation (H/R) injury. METHODS: Neonatal rat ventricular myocytes were pretreated with TNF-α or sodium nitroprusside (SNP) or L-arginine (L-Arg), respectively, for 12 h and then subjected to continuous hypoxia for 12 h, followed by reoxygenation for 6 h. The manganese superoxide dismutase (Mn-SOD) activity of the cells was measured after H/R. Myocyte injury was determined by the release of lactic dehydrogenase (LDH). RESULTS: TNF-α (10⁵ U/L) significantly increased the Mn-SOD activity and decreased release of LDH from ventricular myocytes. The cardioprotection against H/R injury was induced by the pretreatment with SNP (5 μmol/L) or L-Arg (5 mmol/L), which was blocked by ODQ (10 μmol/L), the specific sGC inhibitor, and Chel (5 μmol/L), the specific PKC inhibitor. Pretreatment with L-NAME (100 μmol/L), ODQ, Chel, antoxidant 2-MPG (400 μmol/L) or tyrosine kinase inhibitor genistein (50 μmol/L) attenuated the increased Mn-SOD activity and reduced LDH level induced by TNF-α. CONCLUSION: The results suggest that NO may play a role in TNF-α-induced cardioprotection, which is mediated by sGC and PKC.     

Changes of potassium currents in rabbit ventricle with healed myocardial infarction

AIM: To elucidate the mechanism of arrhythmia in healed myocardial infarction (HMI), and to investigate the changes of action potential duration (APD),transient outward potassium current (I_to), delayed rectifier potassium current (I_K) and inward rectifier potassium current (I_K1) of left ventricular myocytes in noninfarcted zone of HMI. METHODS: 12 rabbits were randomly assigned in two groups: HMI group (thoracotomy and ligation of the circumflex coronary); sham-operated group (thoracotomy but no conorary ligation). 3 months after operation, whole cell patch clamp technique was used to record APD, I_to, I_K and I_K1 of ventricular myocytes in non-infarcted zone. RESULTS: Membrane capacitance was larger in HMI group than that in sham-operated group. Action potential duration was lengthened significantly in HMI group and early after depolarization (EAD) appeared in HMI group. The densities of I_to, I_K,tail and I_K1 were reduced significantly in HMI group (P<0.01), from (6.72±0.42) pA/pF, (1.54±0.13) pA/pF and (25.6±2.6) pA/pF in Sham-operated group to (4.03±0.33) pA/pF, (1.14±0.11) pA/pF and (17.6±2.3) pA/pF, respectively. CONCLUSION: The reduced densities of I_to, I_K,tail and I_K1 in ventricular myocytes of non-infarcted zone in HMI are responsible for the prolongation of APD and the presentation of EAD, which play important roles in the malignant arrhythmia of HMI.     

中国北方沙尘天气原因探讨

我国是沙尘暴易发的国家,进入20世纪90年代以来,强沙尘暴有频率增加、强度加大、范围扩展、危害程度加剧的趋势。沙尘暴的发生危害范围亦逐渐从西北干旱经济落后区扩展到经济发达的北京、天津及华北平原区,近年来的沙尘暴造成了社会经济和人民生命财产的重大损失。受大气环流场和季风气候类型影响,中国冬、春盛吹西北风,强劲而干燥。发生沙尘暴的天数与大风日数和地面热力稳定程度相关,3-5月中国西北内陆地表增温大,是风力场和热力场极不稳定的季节,地表气候容易发生蠕动,沙尘暴便由此启动并易发。除自然要素外,不合理的人类活动也将诱发沙尘暴天气的发生,有些情况下还起到比自然要素更重要的作用。从生态地理区域的角度看,沙尘暴的源地在干旱和半干旱地区,由于大气环流的作用,影响到下风向的半湿润甚至湿润地区。无论何地干旱、半干旱地区都将存在沙尘暴发生的自然条件,而其下风向必将受到不同程度的影响,只是因为中国的季风气候,决定西北干旱、半干旱地区发生的沙尘暴必然影响东南部地区。在现有的科学技术条件下,人类所能做的就是调节自身的行为。因此,在沙尘暴源地实施生态建设是减缓沙尘暴发生的最重要措施,也是消除东部城市沙尘天气的主要途径。根据生态地理区域的特征,沙尘暴源地的干旱区、半干?     

Bone marrow mesenchymal stem cells are induced to differentiate into cardiomyocytes by hepatocyte growth factor in vitro

AIM: To explore a new method of hepatocyte growth factor (HGF) inducing bone marrow mesenchymal stem cells (MSC) to differentiate into cardiomyocytes. METHODS: Bone marrow MSC was cultured with DMEM media (10% fetal calf serum) 4-6 passages, and induced by HGF (10 μg/L) for 30 d. Automatical beating of the differentiated cells was observed daily with transverse microscopy, or under condition of 0.1% isoproterenol or cal-cium-deprived incubation. Specific cardiac myosin in the cells was indentified by immunochemistry. RESULTS: At 14-20 d of differentiation, bone marrow mesenchymal stem cells formed clones, in 10%-50% of which spontaneous beating cell-mass had come to continuously exist. Isoproterenol increased the beating rate and calcium-deprived media inhibited the beating. The cells were identified to be cardiomyocytes by expression of cardiac myosin heavy chain. CONCLUSION: HGF may induce bone marrow mesenchymal stem cells into cardiomyocytes with high efficiency, but the differentiating pathway of stem cells remains to be further studied.     

秦巴山区养羊户适度经营规模的研究

通过对秦巴山区陕西省西乡县15个典型陕南白山羊养殖专业户的资金投入、羊群结构、草地资源、经济效益等情况的调查，分析了养羊户的资源利用和生产经营状况，确定了与山羊生产密切相关的12个变量，即种公羊数、基础母羊数、后备母羊数、育肥羊数、羊舍面积、草地补种及施肥费用、医杂费、氨化或青贮饲料量、补饲精料量、工作日、投资额，并确定了各变量的参数值，以利润最大为目标函数，然后运用线性规划模型，计算出不同投资、不同人力及草地资源等条件下的适度经营规模。结果表明，养羊户的投资额是决定适度规模的主要因素。根据投资和羊群基础母羊数量设计的三种典型经营条件下，基础母羊全部留种的经营方式可获最大投资收益率(140．1％)；基础母羊数量达到20只以上，自繁种公羊的经营方式的最大投资收益率为74．0％；资金有限，人工授精配种的经营方式的投资收益率最低，为73．1％。