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61.
62.
L C Stephens T E Schultheiss K J Vargas D M Cromeens K N Gray K K Ang 《Journal of medical primatology》1989,18(5):383-396
The various glands of rhesus monkey eyelids and human eyelids are similar. Numerous modified sebaceous glands are located along the tarsus. These conform with the meibomian glands, while typical sebaceous glands associated with the hair follicles of the lashes are consistent with the glands of Zeis. Lobules of accessory lacrimal tissue, corresponding to the glands of Krause and Wolfring, are located in the conjunctiva of the fornix and along the orbital border of the tarsal plate. Goblet cells are plentiful in the mucosa of the palpebral and bulbar conjunctiva, and along the lid margin are the sweat glands of Moll. 相似文献
63.
The evolutionary origins of organelles 总被引:37,自引:0,他引:37
M W Gray 《Trends in genetics : TIG》1989,5(9):294-299
Analysis of organellar genomes strongly supports the idea that chloroplasts and mitochondria originated in evolution as eubacteria-like endosymbionts, whose closest contemporaries are cyanobacteria and purple photosynthetic bacteria, respectively. However, there is still much debate about whether a single endosymbiotic event or multiple ones gave rise to each organelle in different eukaryotes, and considerable uncertainty about what has happened to the genomes of chloroplasts and mitochondria since their appearance in the eukaryotic cell. 相似文献
64.
Effect of acyl chain composition on salt-induced lamellar to inverted hexagonal phase transitions in cardiolipin 总被引:3,自引:0,他引:3
Salt-induced fluid lamellar (L alpha) to inverted hexagonal (HII) phase transitions have been studied in diphosphatidylglycerols (cardiolipins) with different acyl chain compositions, using 31P nuclear magnetic resonance (NMR) spectroscopy. Cardiolipins with four myristoyl chains, tetramyristoyl cardiolipin (TMCL), and with four oleoyl chains, tetraoleoyl cardiolipin (TOCL), were synthesized chemically. TMCL was found to undergo a thermotropic lamellar gel to lamellar liquid-crystalline phase transition at 33-35 degrees C. This lipid exhibited an axially symmetric 31P-NMR spectrum corresponding to a lamellar phase at all NaCl concentrations between 0 and 6 M. In the case of TOCL, formation of an HII phase was induced by salt concentrations of 3.5 M NaCl or greater. These observations, taken together with earlier findings that bovine heart cardiolipin aqueous dispersions adopt an HII phase at salt concentrations of 1.5 M NaCl or greater, indicate that increasing unsaturation and length of the acyl chains favour formation of the HII phase in diphosphatidylglycerols. 相似文献
65.
The CD spectra of four filamentous bacteriophages--fd, IKe, Pf1, and Pf3--were analyzed to determine the alpha-helix contents of their major coat proteins. Measured spectra included the 192-nm band so that analyses could be carried out over the full wavelength range of the reference spectra for protein secondary structures available (a) from globular proteins [J.T. Yang, C.S.C. Wu, and H.M. Martinez (1986) Methods in Enzymology 130, 208-269] and (b) from poly(L-lysine) [N. Greenfield and G.D. Fasman (1960) Biochemistry 8, 4108-4116]. Extended analyses were also performed with the addition of the spectrum of a model beta-turn to the Greenfield and Fasman reference set, with the spectrum of a short alpha-helix in the Yang et al. reference set, and with an estimate of the spectrum of Trp added to both reference sets. The reference set based on the simple poly(L-lysine) polypeptide, plus a spectrum of a model beta-turn or of Trp, gave reasonably good fits to the measured spectra for all four phages and yielded the largest percentages of alpha-helix. The class I phages--fd and IKe--had large percentages of alpha-helix of 98 +/- 2 and 97 +/- 5%, respectively, while the two class II phages--Pf1 and Pf3--had similar but smaller alpha-helix contents of 83 +/- 6 and 84 +/- 2, respectively. While these alpha-helix contents were within the ranges previously reported from CD spectra of these phages in solution, they were more precise, and they indicated that the coat proteins of the intact phages have CD spectra that are probably modeled better by the reference spectra of polypeptides than by those of globular proteins. 相似文献
66.
Two bovine genes for mitochondrial ADP/ATP translocase expressed differences in various tissues 总被引:7,自引:0,他引:7
Two different bovine cDNAs have been characterized that encode closely related homologues of the mitochondrial membrane carrier protein ADP/ATP translocase. One of them codes for the protein that has been characterized previously from bovine heart mitochondria, and the other codes for a protein that differs from it in 33 amino acids out of 297. Including the base substitutions required to bring about these changes in amino acid sequence, the coding regions of the cDNAs differ at 184 positions. In addition, they are extensively diverged in their 3' noncoding sequences, which differ greatly in both length and sequence, and these segments of the cDNAs have been used as hybridization probes to demonstrate that the expression of the two genes giving rise to the two proteins is very different in various bovine tissues. Expression of one gene predominates in heart muscle and that of the other in intestine. Hybridization experiments with digests of genomic DNA have shown the presence of numerous sequences related to the two cDNAs in both the bovine and human genomes. Some of these probably arise from pseudogenes, but three expressed genes have been detected in the human genome. The study of the regulation of the expression of these genes may help to illuminate the basis of tissue-specific human mitochondrial diseases which arise because of defects in mitochondrial enzymes only in the affected tissue and not in other tissues of the same individual. 相似文献
67.
Helical complexes formed between fd DNA and reductively methylated fd gene 5 protein were indistinguishable by electron microscopy from complexes formed with the nonmethylated protein. 13C NMR spectroscopy of 13C-enriched N epsilon, N epsilon-dimethyllsyl residues of the protein showed that three of these residues (Lys-24, Lys-46, and Lys-69) were selectively perturbed by binding of the oligomer d(pA)7. These were the same lysyl residues that we previously found to be most protected from methylation by binding of the protein to poly[r(U)] [Dick, L. R., Sherry, A. D., Newkirk, M. M., & Gray D. M. (1988) J. Biol. Chem. 263, 18864-18872]. Thus, these lysines are probably directly involved in the nucleic acid binding function of the protein. Negatively charged chelates of lanthanide ions were used to perturb the 13C NMR resonances of labeled lysyl and amino-terminal residues of the gene 5 protein. The terbium chelate was found to bind tightly (Ka approximately 10(5) M-1) to the protein with a stoichiometry of 1 chelate molecule per protein dimer. 13C resonances of Lys-24, Lys-46, and Lys-69 were maximally shifted by the terbium chelate and were maximally relaxed by the gadolinium chelate. Also, the terbium chelate was excluded by the oligomer d(pA)7. Computer fits of the induced chemical shifts of 13C resonances with those expected for various positions of the terbium chelate failed to yield a possible chelate binding site unless the chemical shift for Lys-24 was excluded from the fitting process.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
68.
M Hirasawa K A Gray M R Ondrias R W Larsen R W Shaw K J Morrow D B Knaff 《Biochimica et biophysica acta》1989,994(3):229-234
A recently discovered form of spinach catalase that contains both a novel heme and protoheme as prosthetic groups has been characterized using immunological and spectroscopic techniques. The enzyme appears to be a dimer of identical Mr 60,000 monomers. Extraction of the non-covalently bound prosthetic groups, followed by thin-layer chromatography of the extract, suggested that the novel heme contains four carboxylic acid side-chain groups. The resonance Raman spectrum of the resting enzyme indicates that the protoheme prosthetic group is five-coordinate and high-spin. The enzyme was shown to bind formate, azide and cyanide. Cyanide and azide binding to catalase are biphasic, suggesting the existence of two different binding sites for cyanide and azide in the enzyme. Results obtained from EPR and resonance Raman spectroscopies also support the hypothesis that two different ligand-binding sites are present in the enzyme. Western blots suggest that the Mr 60,000 peptide of the novel heme-containing catalase is similar or identical to that of a previously characterized, exclusively protoheme-containing, tetrameric catalase. 相似文献
69.
Inoculation of mature gerbils with BCG gave protection to subsequent infection with B. divergens when inoculated by the intracardiac and intraperitoneal routes, the latter showing a dose dependent relationship. BCG vaccination was most effective in immature gerbils (less than 4 weeks old), which are innately resistant to B. divergens. Vaccination of gerbils with killed Propionesbacterium acne and zymosan A failed to elicit a protective response, which contrasts conspicuously with rodent babesia studies. Incubation of B. divergens-infected gerbil blood with hydrogen peroxide produced parasite inhibition only at the highest concentration and treatment of parasitized gerbils with the oxidative radical inducer, alloxan monohydrate, gave equivocal results so it is evident that, unlike Plasmodium spp., B. divergens is not significantly susceptible to the action of reactive oxygen forms. 相似文献
70.
The epsilon-subunit of ATP synthase from bovine heart mitochondria. Complementary DNA sequence, expression in bovine tissues and evidence of homologous sequences in man and rat. 总被引:1,自引:1,他引:0 下载免费PDF全文
The epsilon-subunit of ATP synthase from bovine heart mitochondria is assembled into the extrinsic membrane sector, F1-ATPase. The mature protein is 50 amino acid residues in length and its function is unknown. It is a nuclear gene product that is imported into the organelle. A mixture of 64 oligonucleotides 17 bases long, designed on the basis of the known protein sequence, was synthesized and used as a hybridization probe to isolate a cognate cDNA clone from a bovine library. The DNA sequence of this clone was determined, and the protein sequence of the epsilon-subunit deduced from it agrees exactly with that determined by direct sequence analysis of the protein isolated from bovine hearts. The bovine cDNA was used as a hybridization probe to examine the expression of the epsilon-subunit in various bovine tissues. mRNAs related to the cDNA are found in all of these tissues, and no evidence was obtained of the presence of mRNAs for the epsilon-subunit with similar coding sequences and dissimilar 3' non-coding regions. By hybridization experiments with digests of DNA from cow, man and rat it has been shown that sequences related to the bovine cDNA are present in the genomes of all three species. More than one related sequence was detected in all cases, indicating the presence in all three genomes of more than one gene and/or pseudogenes. 相似文献