Arrangement of subunit IV in beef heart cytochrome c oxidase probed by chemical labeling and protease digestion experiments

The arrangement of subunit IV in beef heart cytochrome c oxidase has been explored by chemical labeling and protease digestion studies. This subunit has been purified from four samples of cytochrome c oxidase that had been reacted with N-(4-azido-2-nitrophenyl)-2-aminoethyl[35S]-sulfonate (NAP-taurine), diazobenzene[35S]sulfonate, 1-myristoyl-2-[12-[(4-azido-2-nitrophenyl)amino]lauroyl]-sn-glycero-3- [14C]phosphocholine (I), and 1-palmitoyl-2-(2-azido-4-nitrobenzoyl)-sn-glycero-3-[3H]phosphocholine (II), respectively. The labeled polypeptide was then fragmented by cyanogen bromide, at arginyl side chains with trypsin (after maleylation), and the distribution of the labeling within the sequence was analyzed. The N-terminal part of subunit IV (residues 1-71) was shown to be heavily labeled by water-soluble, lipid-insoluble reagents but not by the phospholipid derivatives. These latter reagents labeled only in the region of residues 62-122, containing the long hydrophobic and putative membrane-spanning stretch. Trypsin cleavage of native cytochrome c oxidase complex at pH 8.2 was shown to clip the first seven amino acids from subunit IV. This cleavage was found to occur in submitochondrial particles but not in mitochondria or mitoplasts. These results are interpreted to show that subunit IV is oriented with its N terminus on the matrix side of the mitochondrial inner membrane and spans the membrane with the extended sequence of hydrophobic lipid residues 79-98 buried in the bilayer.     

中国东北地区常见有瓣蝇类调查初步报告

与人类杂处的蝇类,在我国东北地区的分布情况尚少系统调查。作者于1956年5月、8月曾赴内蒙东北部(伊图里河、图里河),6月、7月赴营口、盘山(田庄台),借这些机会,顺便采集了蝇类标本;同年9月组内同志去绥中也采回部分标本;1957年5月至10月作者又赴吉林、辽宁两省各地进行了蝇类调查。其中有瓣蝇类已经定名的共计5科26属68种,有6种为国内新记录。兹将结果报告如下:     

我国赫坎按蚊群内中华按蚊不同类型的研究——Ⅳ.幼虫形态的比较

对于赫坎按蚊群内(Anopheles(A.)hyrcanus group.)用四龄幼虫的形态来区别不同种型,在国外曾有若干报导,如马来亚(Reid,1953;1963)、日本(Otsuru and Ohmori,1960)、菲律宾(Baisas et al.,1936等)及印澳(Bonne-Wepsrer and Swellengrebel,1953)等,但在国内对这方面的研究很少。1938年林樑城和姚永政对于南京地区中华按蚊(统称)幼     

酪氨酸对人离体滋养层细胞孕酮与hCG分泌的影响

本文观察三种剂量(2×10~(-5)mol/L,2×10~(-4)mol/L和2×10~(-3)mol/L)的酪氮酸对离体培养的滋养层细胞孕酮及hCG分泌的影响,并对其抑制效应的机理作了初步探讨。实验结果表明,三种剂量的酪氨酸均可抑制滋养层细胞孕酮分泌(P<0.01),但是,在孕酮分泌受酪氨酸抑制的同时,未见对hCG分泌发生影响(P>0.05),进一步观察了酪氨酸对滋养层细胞3β-羟甾脱氢酶活性的影响,结果表明,酪氨酸能显著抑制3β-羟甾脱氢酶活性,提示酪氨酸对滋养层细胞孕酮生成的抑制作用与抑制3β-羟甾脱氢酶活性有关。     

胄蝗属一新种及其染色体组型与带型分析(直翅目:蝗总科)

胄蝗属(Stolzia Willemse)的种类,已知分布于菲律宾、印度尼西亚、马来西亚及我国等地区。在我国已知仅一种,即海南胄蝗Stolzia hainanensis(Tinkham).作者等于1985年9月,在海南省尖峰岭地区采集时,采得胄蝗属一新种,我们同时对该种蝗虫的染色体组型和带型进行了观察,现记述如下。 模式标本保存于陕西师范大学生物系蝗虫研究室。 尖峰胄蝗Stolzia jianfengensis新种 雄性:体中小型,密具皱纹和刻点。头顶近平,狭三角形,突出于触角基节之前,眼间距极狭,其最狭处狭于触角基节的宽度;颜面侧观倾斜,在触角基部之间的下方略凹曲,颜     

Construction and packaging of pseudotype retrovirus containing human N—ras cDNA antisense sequence and its biological effects on human hepatoma cells

N-ras is one of the transforming genes in human hepatic cancer cells.It has been found that N-ras was overexpressed at the mRNA and protein level in hepatoma cells.In order to explore the biological roles of N-ras in human hepatic carcinogenesis and the potential application in control of cancer cell growth,a preudotype retrovirus containing antisense sequence of human N-ras was constructed and packaged.A recombinant retrovirus vector containing antisense or sense sequences of N-ras cDNA was constructed by pZIP-NeoSV(X)1.The pseudotype virus was packaged ang rescued by transfection and infection in PA317 and ψ 2 helper cells.It has been demonstrated that the pseudotype retrovirus containing antisense N-ras sequence did inhibit the growth of human PLC/PRF/5 hepatoma cells accompanied with inhibition of p21 expression,while the retrovirus containing sense sequence had none.The pseudotype virus had no effect on human diploid fibroblasts.     

吉林省寄螨亚科三新种(啤螨目:寄螨科)

本文记述寄螨亚科(Parasitinae)三新种。模式标本保存于吉林省地方病第一防治研究所。文内测量单位为微米,括号内为测量平均值。     

腐霉属分类性状评价及其中国的种

本文对腐霉属Pythium Pringsheim的研究历史作了简单的回顾,对该属的分类性状和系统进行了论述和评价,最后对中国已发现的55种腐霉,以检索表的方式进行了分类、检索。     

Plasma membrane isolation from freshwater and salt-tolerant species of Chara: antibody cross-reactions and phosphohydrolase activities

Plasma membranes were isolated using the aqueous polymer two-phasepartition method from the algae Chara corallina and Chara longifolia,algae which differ in their ability to grow in saline environments.Enrichment of plasma membrane and depletion of tonoplast relativeto the microsomal fraction was monitored using phosphohydrolaseassays and crossreactions to antibodies raised against higherplant transporters. Antibodies to the vacuolar ATPase and pyrophosphatasecross-reacted with epitopes in the microsomal fraction, butshowed little affinity for the plasma membrane fraction. Pyrophosphataseactivity also declined in the plasma membrane fraction relativeto the microsomal fraction. The V-type H⁺ -ATPase activity,sensitive to nitrate or bafilomycin, was low in both fractions,though the cross-reaction to the antibody was reduced in theplasma membrane fraction. By contrast, the antibody recognitionof a P-type H⁺-ATPase amino acid sequence from Arabidopsis didnot occur strongly in the anticipated 90–100 kDa range.While there was enhanced recognition of a polypeptide at around140 kDa in the plasma membrane fraction, salt treatment of Charalongifolia resulted in plasma membrane fractions with reducedamounts of this epitope, but no change in vanadate-sensitiveATPase activity, suggesting that it does not represent the onlyP-type ATPase. Microsomal membranes from saltadapted C. longifoliahave higher reactivity with the antibody to the tonoplast ATPase. Key words: Chara, plasma membrane, salt tolerance, ATPase     

Deep-level diagnostic value of the rDNA-ITS region

The similarity of certain reported angiosperm rDNA internal transcribed spacer (ITS) region sequences to those of green algae prompted our analysis of the deep-level phylogenetic signal in the highly conserved but short 5.8S and hypervariable ITS2 sequences. We found that 5.8S sequences yield phylogenetic trees similar to but less well supported than those generated by a ca. 10-fold longer alignment from rDNA-18S sequences, as well as independent evidence. We attribute this result to our finding that, compared to 18S, the 5.8S has a higher proportion of sites subject to vary and greater among-site substitution rate homogeneity. We also determined that our phylogenetic results are not likely affected by intramolecular compensatory mutation to maintain RNA secondary structure nor by evident systematic biases in base composition. Despite historical homology, there appears to be no ITS2 primary sequence similarity shared sufficient similarity to cluster correctly on the basis of alignability. Our results indicate that groups, however, share sufficient similarity to cluster correctly on the basis of alignability. Our results indicate that ITS region sequences can diagnose organismal origins and phylogenetic relationships at many phylogenetic levels and provide a useful paradigm for molecular evolutionary study.