温度对黄粉虫成虫繁殖的影响

黄粉虫是多种小型经济动物的常用优良饵料,本试验在20.1℃,24.0℃、28.5℃、31.7℃和36.5五种恒温下饲养该成虫结果,成虫寿命平均分别为63.0、54.2、38.8、38.0和26.1天;每雌平均产卵量则分别为200.3、207.3、122.3、115.8和81.2粒,成虫平均生产1g卵消耗麸皮量分别为2.66、2.00、2.19、2.14和4.15g。结果说明人工繁殖黄粉虫的成虫期温度以24℃为最适宜。     

杉木、台湾杉、香杉逐步判别分析

通过对杉木、台湾杉、香杉２２个种源的叶长、叶宽、叶厚、维管束的宽与厚、栅栏组织厚、机械组织厚、表皮厚和气孔数等９个叶性状进行逐步判别分析,选取栅栏组织厚（Ｘ＿６）、叶长（Ｘ＿１）和叶厚（Ｘ＿３）三个重要因子,建立优化判别方程：Ｆ＿１（台湾杉）＝－２３５．８７１４＋１７．３１０４Ｘ＿６＋２６．３５８７Ｘ＿１＋５．９０４６Ｘ＿３Ｆ＿２（杉木）＝－５６４．９２５９＋７８．４２５４Ｘ＿６＋９３．１９２３Ｘ＿１＋０．６２９５Ｘ＿３Ｆ＿３（香杉）＝－３４９．４２０５＋６４．１９２６Ｘ＿６＋６２．６４７９Ｘ＿１＋０．８９６９Ｘ＿３定量地区分这三个树种,旨在对逐步判别分析法在树种分类上的应用进行探讨。     

Uniparental Mitochondrial Transmission in the Cultivated Button Mushroom, Agaricus bisporus

A uniparental mitochondrial (mt) transmission pattern has been previously observed in laboratory matings of the cultivated mushroom Agaricus bisporus on petri dishes. In this study, four sets of specific matings were further examined by taking mycelial plugs from the confluent zone of mated homokaryons and inoculating these plugs into rye grain for laboratory fruiting and for fruiting under industrial conditions. Examination of the mt genotype of each individual fruit body for mt-specific restriction fragment length polymorphisms further confirmed that the mt genome was inherited uniparentally. The vegetative radial growth and the fruiting activity of two pairs of intraspecific heterokaryons, each pair carrying the same combination of nuclear genomes but different mt genotypes, were compared. Our results suggested that the mt genotype did not appreciably affect radial growth or fruiting activity. The failure to recover both heterokaryons, each carrying either parental mt genotype in any given cross, therefore clearly indicated that in matings of A. bisporus, the mt genome from one of the parental homokaryons is either selectively excluded in the newly formed heterokaryon or selectively eliminated in the immediate heterokaryotic mitotic progeny of the newly formed heterokaryon.     

Metabolic activation of unsaturated derivatives of valproic acid. Identification of novel glutathione adducts formed through coenzyme A-dependent and -independent processes

The ability of 2-n-propyl-4-pentenoic acid (Δ⁴-VPA) and 2-n-propyl-2(E)-pentenoic acid ([E]-Δ²-VPA), two unsaturated metabolites of valproic acid (VPA), to form reactive intermediates, deplete hepatic glutathione (GSH) and cause accumulation of liver triglycerides was investigated in the rat. With the aid of ionspray liquid chromatography-tandem mass spectrometry (LC-MS/MS), three GSH adducts were detected in the bile of Δ⁴-VPA-treated animals and were identified as 4-hydroxy-5-glutathion-S-yl-VPA-γ-lactone, 5-glutathion-S-yl-(E)-Δ³-VPA and 3-oxo-5-glutathion-S-yl-VPA. A fourth conjugate was identified tentatively as 4-glutathion-S-yl-5-hydroxy-VPA. Quantitative analysis of the corresponding N-acetylcysteine (NAC) conjugates in urine indicated that metabolism of Δ⁴-VPA via the GSH-dependent pathways accounted for approximately 20% of an acute dose (100 mg kg⁻¹ i.p.). In contrast, when rats were given an equivalent dose of (E)-Δ²-VPA, only one GSH adduct (5-glutathion-S-yl-(E)-Δ³-VPA) was detected at low concentrations in bile. In vitro experiments with rat liver mitochondria demonstrated that Δ⁴-VPA undergoes coenzyme A- and ATP-dependent metabolic activation in this organelle via the β-oxidation pathway to intermediates which bind covalently to proteins. When liver homogenates and hepatic mitochondria from rats injected with Δ⁴-VPA, (E)-Δ²-VPA or VPA were analyzed for GSH content, it was found that only Δ⁴-VPA depleted GSH pools significantly. Treatment of rats with Δ⁴-VPA and (to a lesser extent) VPA led to an accumulation of liver triglycerides, whereas (E)-Δ²-VPA had no measurable effect. It is concluded that Δ⁴-VPA undergoes metabolic activation by both microsomal cytochrome P-450-dependent and mitochondrial coenzyme A-dependent processes, and that the resulting electrophilic intermediates, which are trapped in part by GSH, may mediate the hepatotoxic effects of this compound. In contrast, (E)-Δ²-VPA is not transformed to any appreciable extent to reactive metabolites, which thus accounts for the apparent lack of hepatotoxicity of this positional isomer in the rat.     

Expression and characterization of virus-like particles containing rubella virus structural proteins.

Rubella virus (RV) virions contain two envelope glycoproteins (E1 and E2) and a capsid protein (C). Noninfectious RV-like particles (VLPs) containing three structural proteins were expressed in a BHK cell line (BHK-24S) by using an inducible promoter. These VLPs were found to resemble RV virons in terms of their size, their morphology, and some biological activities. In immunoblotting studies, VLPs were found to bind similarly to native RV virions with 10 of a panel of 12 RV-specific murine monoclonal antibodies. Immunization of mice with VLPs induced specific antibody responses against RV structural proteins as well as virus-neutralizing and hemagglutination-inhibiting antibodies. After immunization of mice with VLPs, in vitro challenge of isolated lymphocytes with inactivated RV and individual RV structural proteins stimulated proliferation. Our data suggest the possibility of using VLPs as immunogens for serodiagnostic assays and RV vaccines.     

New killing system controlled by two genes located immediately upstream of the mukB gene in Escherichia coli

The nucleotide sequence was determined of the region upstream of the mukB gene of Escherichia coli. Two new genes were found, designated kicA and kicB (killing of cell); the gene order is kicB-kicA-mukB. Promoter activities were detected in the regions immediately upstream of kicB and kicA, but not in front of mukB. Gene disruption experiments revealed that the kicA disruptant was nonviable, but the kicB-disrupted mutant and the mutant lacking both the kicB and kicA genes were able to grow. When kicA disruptant cells bearing a temperature-sensitive replication plasmid carrying the kicA ⁺ gene were grown at 30° C and then transferred to 42° C, the mutant cells gradually lost colony-forming ability, even in the presence of a mukB ⁺ plasmid. Rates of protein synthesis, but not of RNA or DNA synthesis, fell dramatically during incubation at 42° C. These results suggested that the kicB gene encodes a killing factor and the kicA gene codes for a protein that suppresses the killing function of the kicB gene product. It was also demonstrated that KicA and KicB can function as a post-segregational killing system, when the genes are transferred from the E. coli chromosome onto a plasmid.     

向日葵幼苗环旋运动的三维轨迹

采用光学显微镜标尺和垂线原理制作的三维空间点测定仪,对向日葵（Ｈｅｌｉａｎｔｈｕｓ ａｎｎｕｕｓＬ．）幼苗的环旋运动进行了连续测量。结果表明：向日葵环旋运动的轨迹有椭圆型、摆动型和不规则型;同一植株在不同生长阶段所表现的环旋运动轨迹不一定相同,同一株龄的不同个体也不一定具有相同的运动轨迹;运动的方向有左旋和右旋,圆周运动光源可以显著地改变运动方向;从三维角度看,在整个下胚轴生长阶段,环旋运动的振幅存在一个由小变大再由大变小的变化规律     

生态环境对川芎产、质量的影响

生态环境对川芎产、质量的影响丁德蓉,陈兴福,卢进,黄文秀,刘岁荣（四川省中医药研究院药物种植研究所,南川６４８４０８）ＩｎｆｌｕｅｎｃｅｏｆＥｃｏｅｎｖｉｒｏｎｍｅｎｔｏｎｔｈｅＹｉｅｌｄａｎｄＱｕａｌｉｔｙｏｆＬｉｇｕｓｔｉｃｕｍｃｈｕａｎｘｉｏｎ...