Development of sensitive esterase assays based on alpha-cyano-containing esters.

A novel approach is reported for the development of fluorogenic esterase reporters using alpha-cyano-containing esters as substrates. After ester hydrolysis, the released alcohol, a cyanohydrin, rapidly eliminates HCN to yield the corresponding aldehyde resulting in strong fluorescence. The pi conjugation of the resulting aldehyde also greatly enhances UV absorption and red shifts fluorescence emission relative to a corresponding alcohol or phenol. Two substrates, R/S-acetic acid cyano-(6-methoxynaphthalen-2-yl)-methyl ester (compound I) and trans/cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid R/S-cyano-(6-methoxynaphthalen-2-yl)-methyl ester (compound II), were synthesized and evaluated as substrates. Such alpha-cyano substrates possess very low background fluorescence and are more stable under enzyme assay conditions than phenolic substrates due to the aliphatic cyano group. The higher molar absorbtivity and quantum yield of the aldehyde, along with its larger Stokes' shift combined with the increased stability and lower background signal of the cyanohydrin substrate, increases the utility and sensitivity of the resulting assays over current methods. Moreover, compound II showed high selectivity to pyrethroid-cleaving esterases and may provide a direct tool to monitor pyrethroid resistance in insects.     

大鼠隔—海马通路损伤对海马内递质含量及酶活力的影响

单侧切断大鼠海马缴和部分穹窿可使海马部分去神经。损伤后7d,海马内胆碱能系统中乙酰胆碱(ACh)含量下降72.5%,胆碱乙酰基转移酶(ChAT)活力下降45.7%,胆碱酯酶活力下降52.2%,在单胺能系统中,去甲肾上腺素(NA)含量下降16.3%,多巴胺(DA)含量下降31.3%,5-羟色胺含量下降30.3%。在损伤过程中,海马内氨基酸含量没有改变。实验结果表明,海马缴和穹窿是脑内胆碱能和单胺能传入神经到达海马靶区的部分共同通路。     

Nerve growth factor and neuronal cell death

The regulation of neuronal cell death by the neuronotrophic factor, nerve growth factor (NGF), has been described during neural development and following injury to the nervous system. Also, reduced NGF activity has been reported for the aged NGF-responsive neurons of the sympathetic nervous system and cholinergic regions of the central nervous system (CNS) in aged rodents and man. Although there is some knowledge of the molecular structure of the NGF and its receptor, less is known as to the mechanism of action of NGF. Here, a possible role for NGF in the regulation of oxidant--antioxidant balance is discussed as part of a molecular explanation for the known effects of NGF on neuronal survival during development, after injury, and in the aged CNS.     

紫茎泽兰的化学成分初报

紫茎泽兰(Eupalorium adenophorum Spreng)原产中美墨西哥,现在滇南一带广泛分布,对林、牧业生产造成严重危害。其化学成分研究未见报道。 从紫茎泽兰的叶和花序中,分到九个单体,经详细的光谱解析和与标准品对照,其中五个成分的化学结构分别为:正三十二烷n-dotriacontane(1),β-谷甾醇β-sitosterol(2),豆甾醇stigmasterol(3),蒲公英醇棕榈酸酯taraxasteryl palmitate(4),蒲公英醇乙酸酯taraxastcryl acetate(5)。     

胶茶群落及胶林、茶园太阳辐射光谱的研究

1983—1985年,我们进行了胶茶人工群落及胶林、茶园对太阳辐射光谱吸收利用状况的探索研究。着重对可见光谱区的两个吸收带,4000—5000(?)(蓝紫光)、6000—7600A(红橙光)以及红外光谱区的10000—13200(?)(近红外)、14800—18000(?)(远红外)进行了分析讨论,以期从生态和生理的角度阐明群落结构比单一结构的优越性及其对胶、茶产量和品质的影响。     

Serial studies of autologous antibody reactivity to squamous cell carcinoma of the head and neck

Summary In previous studies we evaluated the incidence and specificity of autologous antibody reactivity against squamous cell carcinoma of the head and neck (SCCHN). We were able to demonstrate that autologous antibody reactivity is present in native sera but was usually of too low a titer to allow further analysis. Dissociation of immune complexes by acidification and ultrafiltration of serum augmented autologous antibody reactivity in nine out of nine autologous systems tested. Native antibody and antibody derived from immune complexes produced by the host and reactive with autologous tumor cells may be directed against physiologically relevant antigens. Therefore, correlations of antibody titers with clinical course may provide insight into the nature of the host response to cancer. In the present analysis, serological studies of six patients with SCCHN were performed with serum samples obtained over many months. Results of serial serological assays were correlated to tumor progression and clinical course. Fluctuations in autologous antibody reactivity were noted over time. In four cases, rises in autologous antibody titers preceded the clinical diagnosis of recurrence by several months. Drops in autologous antibody reactivity were noted in two cases following surgery or radiation therapy. In two cases of long-term survivors, no correlation between antibody reactivity and clinical course was noted. Specificity analysis of the six autologous systems demonstrated reactivity against autologous and allogeneic SCCHN as well as melanoma cell lines. These sera did not react with glioma, neuroblastoma, renal cell, breast, bladder and colon carcinoma cell lines nor with fetal calf serum, pooled lymphocytes, red blood cells and platelets. Autologous serial serological studies may provide a means by which to evaluate the host/tumor relationship in patients with SCCHN.     

小麦原胚对外源大分子与不透膜物质的摄入

为检验小麦原胚基端特定位点上的外连丝型胞间连丝和开放孔道在摄取外源物质上的作用,以不透膜的阳离子铁蛋白(cationized ferritin)和萤黄(lucifer yellow CH )为示踪物,对其吸入与传布动态进行了荧光与电子显微镜观察。结果表明,这两种物质确可以以非跨膜运输的方式沿着原胚基端的特定通道进入原胚细胞。     

植物附生微生物与叶部病害生物防治研究进展

人们早已发现绿色植物叶面(phylloplane)栖居有大量微生物。在一百多年前微生物学家就从植物叶面分离到许多真菌和细菌。1910年Potter首先证实,叶面附生微生物在干扰真菌引起的叶部病害中起着重要作用。至本世纪上半叶,叶面微生物仍为人们所忽视。相反,在这期间土壤微生物得到很大发展,在土传植物病原菌生物防治研究方法上取得了很大进展,为后来的植物叶部病害生物防     

The long-distance migration of Nilaparvata lugens (Stål) (Delphacidae) in China: radar observations of mass return flight in the autumn

Abstract.

• 1 A case study is presented of the autumn migration of the brown planthopper, Nilaparvata lugens (Stål), in the area of Nanjing in the People's Republic of China. The study was made using a high frequency (8 mm wavelength) radar and a net suspended from a kytoon.
• 2 The observations confirmed that long-distance return migrations occur in China in mid and late September, with N.lugens being carried on the prevailing north-easterly wind towards the autumn infestation and overwintering areas of the species.
• 3 After mass take-off in the late afternoon or at dusk, the migrants flew for several hours during the evening, often in a dense layer which formed at heights between about 400 and 1000m above ground. These layers often had well-defined ceilings corresponding to an air temperature of about 16°C. The migration height was above the top of the surface temperature inversion, i.e. the migrants did not fly at the height of the warmest air.
• 4 The dense layer concentrations overflying the radar were backtracked to source areas up to 240 km away in the north-east of Jiangsu Province. Planthoppers observed emigrating from the Nanjing area would reach areas in south Anhui Province or north Jiangxi Province if they flew for 12 h.
• 5 There was a second period of mass take-off at dawn. Insect layers sometimes formed but did not last longer than 1–2h.
• 6 The present results were strikingly different from those previously observed in the dry season in the Philippines, where migratory flight durations were largely confined to periods of about 30min at dusk and dawn.
• 7 Our observations are discussed in relation to the equator-wards return migrations undertaken in autumn by other insect species, and the importance of these migrations for the maintenance of long-flying genotypes in the overwintering populations is considered.