几株杆状病毒包涵体蛋白双向高压电泳指纹图谱比较

用蔗糖密度梯度离心提纯的6种昆虫病毒包涵体(BsNPV1,BsNPV2,BtNPV,EpNPV,PrGV,PxGV)经DAS碱解,粗提纯的包涵体蛋白经Sepharose-6B柱层析和Caaalco-prep-disc法进一步纯化后,在SDS-PAGE中显示为一条分子量约28,000d的带。用常规双向免疫扩散法检查各种包涵体蛋白之间的差异,结果表明血清学BsNPV与BtNPV,PrGV与PxGV之间都是不可分辩的。6种包涵体蛋白的双向高压指纹图谱表明,它们的指纹图谱都不同程度地存在着一些相同或十分相似的肽点。就每种病毒的指纹图谱又都是独特的,NPV间相似性低于GV间相似性。我们认为NPV和GV的包涵体蛋白在结构上存在着一些相同的或相似的保守区域,但不同种之间在整个一级结构上是有差异的。利用包涵体蛋白的指纹图谱鉴定杆状病毒是个灵敏可行的方法。     

高寒草甸生态系统牲畜种群结构和动态

本文用Leslie矩阵模型研究了高寒草甸生态系统牲畜种群结构及动态。模型考虑了更加精确的年龄组转移关系,出栏率是种群波动的主要因子。目前,牲畜种群结构不合理,种群数量不能保持平衡。     

裂叶苣荬菜的研究

本文对裂叶苣荬菜(Sonchus arvensis L)进行了初步研究。考察了它的植物生态特征和分布环境,预试了化学成分并进行了临床病例观察。为裂叶苣荬菜以其本名作为治疗肝炎的草药入药提供了可靠的依据。     

浸染豇豆的一种病毒分离物的鉴定

在合肥地区从豇豆带毒实生苗中分离到一株病毒分离物Cp—2.侵染豇豆表现为卷叶、花叶,并使叶片革质化.易经汁液摩擦接种.可经桃蚜、棉蚜、蚕豆好及豆蚜以非持久性方式传播.其寄主范围广泛,能侵染测试的7科20种植物中的11种。稀释限点为10~(-3)～10~(-4),钝化温度为60～65℃,体外存活期7～8天。纯化病毒悬液A260/280为1.523.病毒粒体为杆状,宽约18～20nm,多种长度,优势长度分别为58,98,150nm。在琼脂双扩散试验中不与烟草脆裂病毒(TRV)、豌豆早枯病毒(PEBV)苜蓿花叶病毒(ALMV)、烟草花叶病毒(TMV)的抗血清发生反应。病毒外壳蛋白为单一电泳组分.其分子量为34 800,氨基酸组成中缺精所酸和脯氨酸。根据上述特征,认为Cp—2分离物为一种不隶属于目前确认病毒组群的单一病毒,且在国内外尚未见类似的报道,故暂定名为豇豆蚜传碎裂病毒(Cowpea aphid-borne breakage virus,CABV)。     

Functional and phenotypic modifications induced by IL-4, as single agent or in combination with IL-2, on PBMC preactivated in vivo by alpha-interferon + interleukin-2 therapy

The effect of human IL-4, used as a single agent or in combination with low or high dose IL-2, upon LAK-cell proliferation and activation has been tested on PBMC from patients treated with alpha 2-IFN and IL-2. Four days in vitro culture with IL-4 did not induce any LAK-cell activation; IL-4 induced the proliferation of CD3+ CD4+ T-cells, but decreased the percentage of NK cells in culture samples. When combined with high dose IL-2, IL-4 improved the recovery of MN cell without modification of T-cell subsets; however, IL-4 had no major effect on IL-2-induced NK or LAK cell activity. The combination of IL-4 and low dose IL-2 still significantly improved the total MN cell recovery but did not modify the distribution of T and NK lymphocytes; IL-4 inhibited low dose IL-2-induced NK and LAK cell activity, and increased the BL-esterase activity induced by high or low dose IL-2. The combination of IL-4 and IL-2 did not induce any large variation in the percentage of IL-2R (p55) expressing cells. In all tested conditions, IL-2R (p55) was mainly expressed on CD4+ T cells; less than 2% of the cells coexpressed the NK cell marker CD56 and IL-2R (p55). The effect of IL-4 upon IL-2-induced LAK cell expansion is thus very different on PBMC pre-activated in vivo by alpha IFN + IL-2 therapy than on PBMC pre-treated in vitro with IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)     

家兔早期胚胎细胞发育能力的研究

本文利用胚泡注射法制作嵌合体对家兔交配后96,120和144小时的ICM细胞的发育能力进行了研究。供体胚胎取自青紫兰灰免,受体胚胎取自新西兰白兔,结果表明96和120小时供胚的ICM细胞与96小时受胚胚泡组合后均能参与发育,形成嵌合兔,144小时者未获得嵌合体。由于120小时的ICM细胞发育的2只表型为雄性的嵌合兔,其中1只不育,其性腺和外周血核型表明不育兔为xx/xy性嵌合,性腺中有处于不同发育程度的卵巢和精细管,外周血含xx和xy两种核型。本实验结果首次证明家兔交配后120小时胚泡的ICM细胞仍具有参与嵌合体发育的能力。它不仅能参与体细胞的分化,并具有形成生殖细胞的能力。交配后144小时胚泡的ICM细胞其发育能力似乎已发生了局限。     

Modulation of ζ-Protein Kinase C by Cyclic AMP in PC12 Cells Occurs Through Phosphorylation by Protein Kinase A

Abstract: Although cyclic AMP (cAMP) has been reported to cross talk with the protein kinase C (PKC) system, effects of elevated intracellular cAMP on the activities of specific PKC isoforms have not been studied. We report findings from a permeabilized cell assay that was used to examine changes in the activity of the atypical PKC isoforms brought about by exposure of PC12 cells to agents that elevate intracellular cAMP. We found that increases in intracellular cAMP led to rapid stimulation of atypical PKC activity, 40–70% above control, for a sustained period of time, a response that occurred independent of the phorbol 12-myristate 13-acetate (PMA)-sensitive PKC isoforms. Changes in intracellular cAMP levels resulted in a dose-dependent redistribution of ζ-PKC to the cytoplasm with a concomitant increase in the phosphorylation state of the enzyme. Incubation of purified ζ-PKC with increasing concentrations of PKA likewise caused a twofold increase in the phosphorylation state of ζ-PKC. In contrast to the positive effect that PKA-mediated phosphorylation had on the activity of ζ-PKC, the enzyme displayed reduced binding to ras when phosphorylated. Taken together, these findings are consistent with the hypothesis that protein phosphorylation of PKC acts as a positive effector of its enzyme activity and may serve as a negative modulator for interaction with other proteins.     

Heterogeneity of the glutathione transferase genes encoding enzymes responsible for insecticide degradation in the housefly

One of the four glutathione-S-transferases (GST) that is overproduced in the insecticide-resistant Cornell-R strain of the housefly (Musca domestica) produces an activity that degrades the insecticide dimethyl parathion and conjugates glutathione to lindane. In earlier work, it was shown that the resistant Cornell-R carries an amplification, probably a duplication, of one or more of its GST loci and that this amplification is directly related to resistance. Using polymerase chain reaction (PCR) amplification with genomic DNA, multiple copies of the gene encoding the parathion-degrading activity (called MdGst-3) were subcloned from both the ancestral, insecticide-susceptible strain BPM and from the insecticide-resistant Cornell-R. In BPM, three different MdGst-3 genes were identified while in Cornell-R, 12 different MdGst-3 sequences were found that, though closely related to ancestral genes, had diverged by a few nucleotides. This diversity in MdGst-3 genomic sequences in Cornell-R is reflected in the expressed sequences, as sampled through a cDNA bank. Population heterozygosity cannot account for these multiple GST genes. We suggest that selection for resistance to insecticides has resulted in not only amplification of the MdGst-3 genes but also in the divergence of sequence between the amplified copies. Received: 22 November 1995 / Accepted: 23 February 1996     

Identification and Characterization of Autosomal Genes That Interact with Glass in the Developing Drosophila Eye

The glass gene encodes a zinc finger, DNA-binding protein that is required for photoreceptor cell development in Drosophila melanogaster. In the developing compound eye, glass function is regulated at two points: (1) the protein is expressed in all cells' nuclei posterior to the morphogenetic furrow and (2) the ability of the Glass protein to regulate downstream genes is largely limited to the developing photoreceptor cells. We conducted a series of genetic screens for autosomal dominant second-site modifiers of the weak allele glass(3), to discover genes with products that may regulate glass function at either of these levels. Seventy-six dominant enhancer mutations were recovered (and no dominant suppressors). Most of these dominant mutations are in essential genes and are associated with recessive lethality. We have assigned these mutations to 23 complementation groups that include multiple alleles of Star and hedgehog as well as single alleles of Delta, roughened eye, glass and hairy. Mutations in 18 of the complementation groups are embryonic lethals, and of these, 13 show abnormal adult retinal phenotypes in homozygous clones, usually with altered numbers of photoreceptor cells in some of the ommatidia.     

Replication of a plasmid lacking the normal site for initiation of one strand.

The origin of replication of the plasmid R1162 contains an initiation site for the synthesis of each DNA strand. When one of these sites (oriL) is deleted, synthesis on the corresponding strand is no longer initiated efficiently in vitro by the R1162-encoded replication proteins, and the plasmid is no longer stably maintained in the cell. However, in vivo the two strands of the plasmid duplex molecule are active at a similar level as templates for DNA synthesis, and newly synthesized copies of each strand are incorporated into daughter molecules at a similar rate. No secondary, strong initiation sites on the delta oriL strand were detected in the region of the origin. The delta oriL plasmid induces the SOS response, and this is important for plasmid maintenance even in a recombination-proficient strain. Our results indicate that an SOS-induced host system can maintain an R1162 derivative lacking one of its initiation sites.