Inhibitory effects of endothelin-1 and endothelin-3 on prolactin release: possible involvement of endogenous endothelin isopeptides in the rat anterior pituitary.

Spontaneous prolactin release from the isolated rat anterior pituitary was inhibited by endothelin-1 in a dose-dependent manner (10(-8)-10(-6) M). Endothelin-3 also inhibited spontaneous prolactin release with an almost identical dose-response relationship as endothelin-1. These inhibitory effects were unaffected by application of a dopamine D2-receptor antagonist, YM-09151-2 (10(-7) M). Rat anterior and posterior pituitary glands were abundant in both endothelin-1 and endothelin-3, as compared with other regions of the brain. The present results suggest that endogenous endothelin-1 and endothelin-3 in the anterior and posterior pituitary are involved in the inhibitory regulation of prolactin secretion as autocrine or paracrine factors.     

兰科盆距兰属（Gastrochilus）植物的修订

本文对盆距兰属（Ｇａｓｔｒｏｃｈｉｌｕｓ）植物作了修订,共分３个组,含４６种和１变种,其中１个组（Ｓｅｃｔ．Ｃａｅｓｐｉｔｏｓｉ）和８个种（Ｇ．ｃａｒｎｓｕｓ,Ｇ．ｇａｒｈｗａｌｅｎｓｉｓ,Ｇ．ｌｉｎｅａｒｉｆｏｌｉｕｓ,Ｇ．ｇｕａｎｇｔｕｎｇｅｎｓｉｓ,Ｇ．ｓｕｂｐａｐｉｌｌｏｓｕｓ,Ｇ．ｎａｎｃｈｕａｎｅｎｓｉｓ,Ｇ．ｓａｃｃａｔｕｓａｎｄＧ．ｇｏｎｇｓｈａｎｅｎｓｉｓ）为新的,首次在本文作了描述报导。本属属的形态特征,研究历史和订正后属下的分类群检索表,种的文献引证、简短的特征记要和地理分布以及在属中被排除的分类单位索引均提供在本文。     

A Novel Class of Herbicides (Specific Inhibitors of Imidazoleglycerol Phosphate Dehydratase)

A new mode of herbicidal action was established by finding specific inhibitors of imidazoleglycerol phosphate dehydratase, an enzyme of histidine (His) biosynthesis. Three triazole phosphonates inhibited the reaction of the enzyme with Ki values of 40 [plus or minus] 6.5, 10 [plus or minus] 1.6, and 8.5 [plus or minus] 1.4 nM, respectively, and were highly cytotoxic to cultured plant cells. This effect was completely reversed by the addition of His, proving that the cytotoxicity was primarily caused by the inhibition of His biosynthesis. These inhibitors showed wide-spectrum, postemergent herbicidal activity at application rates ranging from 0.05 to 2 kg/ha.     

国产前原鹅观草的订正

对我国文献中记载的前原鹅观草（Ｒｏｅｇｎｅｒｉａｍａｙｅｂａｒａｎａ（Ｈｏｎｄａ）Ｏｈｗｉ）的标本和植物,与原产于日本的该种进行了比较形态学、细胞学研究,二者差异显著。作者认为我国所记载的该种种名应是山东鹅观草（Ｒｏｅｇｎｅｒｉａｓｈａｎｄｏｎｇｅｎｓｉｓ（Ｂ．Ｓａｌｏｍｏｎ）Ｊ．Ｌ．Ｙａｎｇ,Ｙ．Ｈ．ＺｈｏｕｅｔＹｅｎ）,其内稃先端钝圆,长为外稃的３／４,染色体数为２ｎ＝４ｘ＝２８,具ＳＹ染色体组,结实率达９０％以上,过去被错定为Ｒ．ｍａｙｅｂａｒａｎａ。而Ｒ．ｍａｙｅｂａｒａｎａ在日本系一天然杂种,其内稃先端尖,与外稃等长或稍短,染色体数为２ｎ＝６ｘ＝４２,具ＨＳＹ染色体组,结实率极低,仅０．２％～０．４％。     

Intracellular serine proteinase behaves as a heat-stress protein in nongrowing but as a cold-stress protein in growing populations of Bacillus megaterium

A temperature increase from 35° to 40–42°C enhances the rise of cytoplasmic serine proteinase (ISP1) activity in Bacillus megaterium incubated in a sporulation medium. A temperature shift from 27°C in the growth medium to 35°C in the sporulation medium has the same effect. Elevated temperature stimulates the increase of ISP1 level when applied immediately after the transfer of cells from the growth to the sporulation medium (at T₀) or at T₃, when sporulation becomes irreversible. The cytoplasmic PMSF-resistant activity or the proteolytic activity associated with the membrane fraction is stimulated only slightly or not at all. A temperature increase to 45–47°C suppresses the rise of proteolytic activities in all cell fractions. In addition to the elevation of the ISP1 activity by an upward temperature shift, the rise of this enzyme in nongrowing cells is also stimulated by osmotic stress. In growing populations, in contrast to the rise of the ISP1 activity caused by elevated temperature in nongrowing cells, this proteinase is induced by low temperatures (24–27°C). The ISP1 activity roughly correlates with the enzyme protein concentration determined by immunoblotting.     

Differential modulation of carbachol and trans-ACPD-stimulated phosphoinositide turnover following traumatic brain injury

In the fluid percussion model of traumatic brain injury (TBI), we examined muscarinic and metabotropic glutamate receptor-stimulated polyphosphoinositide (PPI) turnover in rat hippocampus. Moderate injury was obtained by displacement and deformation of the brain within the closed cranial cavity using a fluid percussion device. Carbachol and (±)-1-Aminocyclopentane-trans-1,3.-dicarboxylic acid (trans-ACPD)-stimulated PPI hydrolysis was assayed in hippocampus from injured and sham-injured controls at both 1 hour and 15 days following injury. At 1 hour after TBI, the response to carbachol was enhanced in injured rats by up to 200% but the response to trans-ACPD was diminished by as much as 28%. By contrast, at 15 days after TBI, the response to carbachol was enhanced by 25% and the response to trans-ACPD was enhanced by 73%. The ionotropic glutamate agonists N-methyl-D-aspartate (NMDA), and -amino-3 hydroxy-5-methyl-4-isoxazolepropionate (AMPA), did not increase PPI hydrolysis in either sham or injured rats and injury did not alter basal hydrolysis. Thus, hippocampal muscarinic and metabotropic receptors linked to phospholipase C are differentially altered by TBI.Abbreviations used TBI traumatic brain injury - EAA excitatory amino acids - PPI polyphosphoinositides - IP inositol phosphates - NMDA N-methyl-D-aspartate - AMPA -amino-3-hydroxy-5-methylisoxazole-4-propionate - trans-ACPD (±)-1-Aminocyclopentanetrans-1,3-dicarboxylic acid - LTP long term potentiation     

Methanogenic granular sludge formation in an upflow anaerobic sludge blanket reactir treating synthetic methanolic waste

A laboratory upflow anaerobic sludge blanket reactor, seeded with fine, suspended, bacterial floc with 1.76 g volatile suspended solids/l, was used to treat synthetic methanolic waste. After 180 days of continuous peration, granular sludge with discrete granules of 1 to 2 mm diam. was formed, with 52 g volatile suspended solids/l. Granules were brown, relatively soft and had a settling velocity of 1.61 cm/s. Extracellular polymeric matter extracted from the granular sludge had high carbohydrate content but low nucleic acid content. The ash of the granular sludge contained Na⁺, K⁺ and Mg²⁺ up to 15.0, 11.7 and 3.75 mg/g, respectively. Scanning and transmission electron microscopy revealed that the granular sludge was dominated by methanogens resembling Methanosarcina.The authors are with the Department of Environmental Engineering, Faculty of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565, Japan     

PFP的研究进展

焦磷酸:果糖-6-磷酸1-磷酸转移酶(PFP)可催化果糖-6-磷酸与果糖-1,6-二磷酸间的可逆转变.该酶广泛存在于各种高等植物及一些微生物体内.文章综述了90年代以来有关PFP的一些研究进展.包括:PFP的种类与亚基构成、活性中心、底物特异性、酶活性的调节及功能等.     

海马内生长抑素与γ－氨基丁酸在大鼠穿梭箱主动回避反应中的作用

本实验以大鼠穿梭箱主动回避反应（ＡＡＲ）的习得和消退为学习记忆的指标,研究了海马内生长抑素（ＳＳ）和γ－氨基丁酸（ＧＡＢＡ）在学习记忆中的作用。结果如下：（１）经训练而建立了ＡＡＲ的大鼠,其海马内ＳＳ较对照组显著增高,而海马内ＧＡＢＡ含量却明显降低;（２）海马内注入ＳＳ的耗竭剂半胱胺（Ｃｙｓ,２０ｇ／Ｌ）使大鼠ＡＡＲ的习得受到明显损害,ＡＡＲ的消退显著加速,海马内ＳＳ明显降低,而ＧＡＢＡ含量却显著升高;（３）海马内注入ＧＡＢＡ（２００ｇ／Ｌ）使大鼠ＡＡＲ的消退显著加速的同时,其海马内ＳＳ含量亦显著降低。由此表明,海马内ＳＳ可能有促进学习记忆的作用,而海马内ＧＡＢＡ升高则有相反的效应;二者在海马调控学习记忆过程中具有重要作用。