Moth sex-pheromone biosynthesis is inhibited by the herbicide diclofop

Pheromones of nocturnal moths are derived from fatty acids produced as a result of the activity of acetyl-CoA carboxylase. This timely production is initiated in nocturnal moths by a tropic peptide, pheromone biosynthesis activating neuropeptide released into the hemolymph. In monocotyledonous plants, specific plastid acetyl-CoA carboxylase is inhibited by herbicides that target the eukaryotic form of the enzyme. We report evidence that these herbicides can also target pheromone biosynthesis by a moth, thereby implicating the acetyl-CoA carboxylase as a key regulatory enzyme in the pheromone biosynthetic pathway. These findings, whilst indicating the possible action of such herbicides on non-target organisms, also suggest a novel alternative method of insect pest management, which precludes sex-pheromone production and mating success, thereby reducing insect population growth.     

云南省马铃薯晚疫病菌的交配型、抗药性及生理小种分布的研究

 从云南省陆良县、建水县和南涧县采集2000年秋播的马铃薯晚疫病标本,分离获得124个致病疫霉菌株,连同1999~2000年分离自昆明、曲靖等地的春播马铃薯晚疫病的10个菌株共134个,采用常规技术对这些菌株进行了交配型、抗药性及生理小种的研究。交配型测定结果为:陆良县的18个菌株中有3个为A₂交配型,其余15个菌株为A₁交配型,建水县和南涧县的106个菌株及昆明、曲靖1999~2000年的10个菌株都是A₁交配型。测定了83个菌株对瑞毒霉(metalaxyl)和烯酰吗啉(dimethomorph)的抗药性,结果有12.0%的菌株对瑞毒霉表现抗性,16.9%表现中抗,71.1%表现敏感,其中陆良、昆明和曲靖的抗瑞毒霉菌株的比例大于建水和南涧的抗药性菌株的比例;所测定的83个菌株都对烯酰吗啉表现敏感。生理小种鉴定结果表明,云南晚疫病菌为3.4、0、3和4生理小种,分别占鉴定菌株总数的48.0%、32.5%、15.6%和3.9%。但南涧仅发现3.4和0小种,而昆明有0、3、3.4和4小种,陆良有0、3和3.4小种,可见昆明和陆良地区的晚疫病菌生理小种比南涧地区的生理小种的组成更趋多样。     

甘肃东方蜜蜂的形态特征研究

通过测定甘肃2个不同样点的4群东方蜜蜂发现,甘肃蜜蜂种群内遗传变异丰富,种群中许多形态性状特征表现出较明显的地理变异性;蜜蜂个体增大、体色变深,具体是:前翅长、前翅宽、背板3,4宽;后腿长、蜡镜长、蜡镜宽、蜡镜间距、腹片3,6的长和宽逐渐增加;背板3,4、小盾片的色素度逐渐加深。这些均具有生态适应意义。     

木质包装中黄斑星天牛微波处理初探

为了探索微波处理作为木质包装替代处理方法的可能性,对不同规格和含水量的杨树木块进行微波处理试验,结果表明:频率为2450MHz的微波能够穿透厚度为10cm的杨树木材;当微波功率为900W时,规格为10cm×10cm×10cm和10cm×10cm×2.5cm的新木块中黄斑星天牛(Anoplophora nobolis)幼虫完全死亡所需时间分别为5min和2min;而干木块中则仅需3min和30s.对微波处理引起木材温度变化和水分损失以及天牛幼虫的水分损失进行了初步研究.     

Pocono mesic till barrens in retreat: topography,fire and forest contagion effects

The Pocono mesic till barrens (PMTB) are a unique assemblage of fire-maintained shrub communities that support numerous rare species. Historically these barrens covered a large area in the vicinity of Long Pond, Pennsylvania, USA. However, due largely to regional fire suppression instituted in the early 1960s, over 70% of the area covered by barrens succeeded to fire-intolerant forest that does not support the rare species. We investigated the influence of forest proximity on barrens succession across three geomorphic types during periods of high fire frequency and fire suppression, testing the hypothesis that forest processes such as seed rain, shading, and detrital enrichment of soils enhances barrens succession through a contagion effect. Evidence of a forest contagion effect should be shown by increased rates of barrens succession with increasing proximity to the nearest forest edge. In order to detect a forest contagion effect, barrens persistence and barrens succession were modeled in proximity zones of 0-50 m, 50-100 m, 100-200 m, and greater than 200 m from the nearest forest edge. We used existing GIS data layers for fire, geomorphology, and vegetation distribution in 1938, 1963, and 1992. The layers were modified and overlain using ArcView software to determine persistence and succession rates for each unique combination of layers in each proximity zone from 1938 to 1963 (pre-fire suppression) and 1963 to 1992 (post-fire suppression). ANCOVA results indicate that proximity to the nearest forest edge significantly affected barrens persistence rates in both time periods, but succession rates were significantly affected in 1938 to 1963 only. Twenty-eight percent of the 1938 barrens succeeded to forest by 1963; 56% of the 1963 barrens became forest by 1992. Results support previous findings that barrens persistence is enhanced by increased fire frequency, and that barrens persist longer where they overlie flat glacial till than on other geomorphology types.     

Upregulation of neurokinin A levels by nerve growth factor in the experimental asthmatic guinea pig

AIM: To explore the regulatory mechanism of nerve growth factor (NGF) on neurokinin A in the experimental asthmatic guinea pig. METHODS: Radioimmunoassay was used to determine the alteration of neurokinin A levels in the lower respiratory tract and visceral sensory afferent sites while NGF was absent (inhalation of NGF antibody through nasal cavity) in the asthmatic guinea pig. RESULTS: The contents of neurokinin A in the trachea, bronchus, lung, C₇-T₅ spinal ganglia and the correspondent spinal dorsal horn, nodose ganglia and solitary nucleus area in the experimental asthmatic guinea pig with the absent of NGF in the respiratory tract were much lower than those in the asthmatic and control groups (P＜0.01). CONCLUSION: NGF upregulated the contents of neurokinin A in the lower respiratory tract and visceral sensory sites of the experimental asthmatic guinea pig, and both might be involved in the pathogenesis of asthma.     

赤峰市松山区土地利用动态变化及其原因分析

以TM遥感资料为信息源 ,利用 3S技术手段 ,对内蒙古自治区赤峰市松山区 1987,1993,2 0 0 0年的土地利用变化进行了分析。结果表明 ,在不同年度内 ,其主要的土地利用类型为耕地、草地和林地。土地利用类型的总量变化也以这 3种土地利用类型和建设用地变化最大。而从年变化速率看 ,1987- 2 0 0 0年 ,以建设用地的增加和未利用土地类型的减少最为快速。从土地利用类型转化的方向看 ,以耕地、草地和林地相互之间的转化最为频繁。从土地利用类型的空间稳定性看 ,耕地的稳定性最高 ,其次为草地 ;而最不稳定的土地利用类型为未利用土地。利用相关分析所作的土地利用变化动因显示 ,该地区土地利用变化的驱动因素主要是社会与经济因素 ,其中以总人口、农业总产值、粮食作物产量总计、农牧民人均纯收入、化肥使用面积和化肥实物量等因子的作用最大 ,而自然因素对该地区土地利用变化的影响极小。     

Human interleukin-1β induces A375-S2 human melanoma apoptosis through caspase pathway

AIM: To study the molecular biological mechanism and signal transduction pathway of interleukin-1β (IL-1β)-induced apoptosis in A375-S2 melanoma cells. METHODS: Photomicrocropy showed typical apoptotic changes. The cytotoxic effect of IL-1β in vitro and influences of caspases in this effect were measured by MTT assay. The cytotoxicity of cells was assessed by LDH-based assay. Degradation of DNA was detected by agarose gel electrophoresis. RESULTS: The inhibitory effect of IL-1β on A375-S2 cell growth was in a dose and time-dependent manner, and cell death rate reached more than 90% at 72 h after treatment with 10^-9mol/L IL-1β. The inhibitors of caspase-family, -1, -3, -8, -9, and -10, partially blocked cell death at early stage. LDH assay showed that major IL-1β-induced cell death was apoptosis, and in a dose and time-dependent manner. Typical apoptotic DNA ladder was observed in agarose gel electrophoresis. CONCLUSION: IL-1β induced apoptosis in melanoma A375-S2 cells by activating caspase pathway.     

昆虫抗菌肽生物学活性及其应用前景

昆虫抗菌肽是昆虫免疫后存在于血淋巴中的一类活性肽 ,具有广谱的抗菌、抗病毒、抑制肿瘤的生物活性 ,具有很高的应用潜力。本文主要介绍昆虫抗菌肽的类型、生理活性、基因的克隆与表达及在动物科学中的应用前景