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101.
Gregory G. Brown Jong Seob Lee Normand Brisson Desh Pal S. Verma 《Journal of molecular evolution》1984,21(1):19-32
Summary We have analyzed the sequences of soybean leghemoglobin genes as an initial step toward understanding their mode of evolution. Alignment of the sequences of plant globin genes with those of animals reveals that (i) based on the proportion of nucleotide substitutions that have occurred at the first, second, and third codon positions, the time of divergence of plant and animal globin gene families appears to be extremely remote (between 900 million and 1.4 billion years ago, if one assumes constancy of evolutionary rate in both the plant and animal lineages) and (ii) in addition to the normal regulatory sequences on the 5 end, an approximately 30-base-pair sequence, specific to globin genes, that surrounds the cap site is conserved between the plant and animal globin genes. Comparison of the leghemoglobin sequences with one another shows that (i) the relative amount of sequence divergence in various coding and noncoding regions is roughly similar to that found for animal globin genes and (ii) as in animal globin genes, the positions of insertions and deletions in the intervening sequences often coincide with the locations of direct repeats. Thus, the mode of evolution of the plant globin genes appears to resemble, in many ways, that of their animal counterparts. We contrast the overall intergenic organization of the plant globin genes with that of animal genes, and discuss the possibility of the concerted evolution of the leghemoglobin genes. 相似文献
102.
Accumulation of messenger RNAs in potato tuber discs was analysed during the hypersensitive response induced by treatment with the biotic elicitor arachidonic acid. In vitro translation of polysomal poly(A)+ RNAs indicated that the accumulation of some sixteen mRNAs varied following treatment with arachidonic acid, and that the level of thirteen of these was increased. Two cDNA closes (pSTH-1 and-2) were isolated from a library of elicitor-treated tissue cDNAs. Northern blot analysis using these clones as molecular probes indicated that the levels of at least two mRNAs were markedly increased after elicitor treatment. In hybrid-released translation experiments, each of the cDNA clones selected more than one mRNA. Translation of these mRNAs yielded two polypeptides of Mr 45 000 (for the pSTH-1 clone), and three polypeptides of Me 17 000 (for the pSTH-2 clone). The low molecular weight polypeptides may correspond to potato pathogenesis-related (PR) proteins. 相似文献
103.
C. Brisson D. O. Azorsa L. K. Jennings S. Moog J. P. Cazenave F. Lanza 《The Histochemical journal》1997,29(2):153-165
Summary CD9 is a 24-kDa membrane glycoprotein expressed on the surface of human platelets and potentially involved in cellular activation
and adhesion functions. This protein belongs to a recently delineated family of cell-surface antigens that span the membrane
four times, called tetraspans, and found mainly in leucocytes and tumour cells. As a first approach to clarify the function
of CD9, we used immunoelectron microscopy to determine the localization of this antigen in human platelets, and compared its
distribution with that of the GPIIb-IIIa integrin, the platelet receptor for fibrinogen. Monoclonal antibodies against CD9
(MAb7) and GPIIb-IIIa (HP1-1D) coupled to colloidal gold of different sizes (5 and 15 nm) were incubated with intact platelets
in suspension or on ultrathin sections of platelets embedded in LR white. CD9 was found in association with GPIIb-IIIa on
the inner face of ·-granule membranes. These two antigens also co-localized on pseudopods of activated platelets and in contact
regions between adjacent platelets. CD63, another member of the tetraspan family, was absent from ·-granules but was associated
with lysosomal structures. Flow cytometric analysis of platelet CD9 with a series of monoclonal antibodies revealed an increased
expression upon thrombin stimulation, confirming the presence of an intracellular granular pool. The observation that CD9
and GPIIb-IIIa are stored in the same intracellular structures and migrate to the same activation zones after platelet stimulation
lends support to previous suggestions of a close association between CD9 and GPIIb-IIIa in human platelets and of a possible
involvement of CD9 in adhesive functions of platelets.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
104.
Vanessa L Brisson Kimberlee A West Patrick KH Lee Susannah G Tringe Eoin L Brodie Lisa Alvarez-Cohen 《The ISME journal》2012,6(9):1702-1714
Dehalococcoides bacteria are the only organisms known to completely reduce chlorinated ethenes to the harmless product ethene. However, Dehalococcoides dechlorinate these chemicals more effectively and grow more robustly in mixed microbial communities than in isolation. In this study, the phylogenetic composition and gene content of a functionally stable trichloroethene-degrading microbial community was examined using metagenomic sequencing and analysis. For phylogenetic classification, contiguous sequences (contigs) longer than 2500 bp were grouped into classes according to tetranucleotide frequencies and assigned to taxa based on rRNA genes and other phylogenetic marker genes. Classes were identified for Clostridiaceae, Dehalococcoides, Desulfovibrio, Methanobacterium, Methanospirillum, as well as a Spirochete, a Synergistete, and an unknown Deltaproteobacterium. Dehalococcoides contigs were also identified based on sequence similarity to previously sequenced genomes, allowing the identification of 170 kb on contigs shorter than 2500 bp. Examination of metagenome sequences affiliated with Dehalococcoides revealed 406 genes not found in previously sequenced Dehalococcoides genomes, including 9 cobalamin biosynthesis genes related to corrin ring synthesis. This is the first time that a Dehalococcoides strain has been found to possess genes for synthesizing this cofactor critical to reductive dechlorination. Besides Dehalococcoides, several other members of this community appear to have genes for complete or near-complete cobalamin biosynthesis pathways. In all, 17 genes for putative reductive dehalogenases were identified, including 11 novel ones, all associated with Dehalococcoides. Genes for hydrogenase components (271 in total) were widespread, highlighting the importance of hydrogen metabolism in this community. PhyloChip analysis confirmed the stability of this microbial community. 相似文献
105.
Structure of the O-chain of the lipopolysaccharide of Haemophilus pleuropneumoniae serotype 1 总被引:2,自引:0,他引:2
By phenol-water extraction an aqueous-phase soluble cellular lipopolysaccharide was isolated from Haemophilus pleuro-pneumoniae serotype 1. It was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, hydrolysis, methylation, and both one- and two-dimensional 1H and 13C nuclear magnetic resonance studies to be an S-type lipopolysaccharide, which could be cleaved to yield a lipid A and an O-chain polysaccharide identified as a high molecular weight branched polymer of a tetrasaccharide repeating unit having the structure: (Formula: see text). 相似文献
106.
Schoenhofen IC McNally DJ Vinogradov E Whitfield D Young NM Dick S Wakarchuk WW Brisson JR Logan SM 《The Journal of biological chemistry》2006,281(2):723-732
Helicobacter pylori and Campylobacter jejuni have been shown to modify their flagellins with pseudaminic acid (Pse), via O-linkage, while C. jejuni also possesses a general protein glycosylation pathway (Pgl) responsible for the N-linked modification of at least 30 proteins with a heptasaccharide containing 2,4-diacetamido-2,4,6-trideoxy-alpha-D-glucopyranose, a derivative of bacillosamine. To further define the Pse and bacillosamine biosynthetic pathways, we have undertaken functional characterization of UDP-alpha-D-GlcNAc modifying dehydratase/aminotransferase pairs, in particular the H. pylori and C. jejuni flagellar pairs HP0840/HP0366 and Cj1293/Cj1294, as well as the C. jejuni Pgl pair Cj1120c/Cj1121c using His(6)-tagged purified derivatives. The metabolites produced by these enzymes were identified using NMR spectroscopy at 500 and/or 600 MHz with a cryogenically cooled probe for optimal sensitivity. The metabolites of Cj1293 (PseB) and HP0840 (FlaA1) were found to be labile and could only be characterized by NMR analysis directly in aqueous reaction buffer. The Cj1293 and HP0840 enzymes exhibited C6 dehydratase as well as a newly identified C5 epimerase activity that resulted in the production of both UDP-2-acetamido-2,6-dideoxy-beta-L-arabino-4-hexulose and UDP-2-acetamido-2,6-dideoxy-alpha-D-xylo-4-hexulose. In contrast, the Pgl dehydratase Cj1120c (PglF) was found to possess only C6 dehydratase activity generating UDP-2-acetamido-2,6-dideoxy-alpha-D-xylo-4-hexulose. Substrate-specificity studies demonstrated that the flagellar aminotransferases HP0366 and Cj1294 utilize only UDP-2-acetamido-2,6-dideoxy-beta-L-arabino-4-hexulose as substrate producing UDP-4-amino-4,6-dideoxy-beta-L-AltNAc, a precursor in the Pse biosynthetic pathway. In contrast, the Pgl aminotransferase Cj1121c (PglE) utilizes only UDP-2-acetamido-2,6-dideoxy-alpha-D-xylo-4-hexulose producing UDP-4-amino-4,6-dideoxy-alpha-D-GlcNAc (UDP-2-acetamido-4-amino-2,4,6-trideoxy-alpha-D-glucopyranose), a precursor used in the production of the Pgl glycan component 2,4-diacetamido-2,4,6-trideoxy-alpha-D-glucopyranose. 相似文献
107.
McNally DJ Hui JP Aubry AJ Mui KK Guerry P Brisson JR Logan SM Soo EC 《The Journal of biological chemistry》2006,281(27):18489-18498
Bacterial genome sequencing has provided a wealth of genetic data. However, the definitive functional characterization of hypothetical open reading frames and novel biosynthetic genes remains challenging. This is particularly true for genes involved in protein glycosylation because the isolation of their glycan moieties is often problematic. We have developed a focused metabolomics approach to define the function of flagellin glycosylation genes in Campylobacter jejuni 81-176. A capillary electrophoresis-electrospray mass spectrometry and precursor ion scanning method was used to examine cell lysates of C. jejuni 81-176 for sugar nucleotides. Novel nucleotide-activated intermediates of the pseudaminic acid (Pse5NAc7NAc) pathway and its acetamidino derivative (PseAm) were found to accumulate within select isogenic mutants, and use of a hydrophilic interaction liquid chromatography-mass spectrometry method permitted large scale purifications of the intermediates. NMR with cryo probe (cold probe) technology was utilized to complete the structural characterization of microgram quantities of CMP-5-acetamido-7-acetamidino-3,5,7,9-tetradeoxy-L-glycero-alpha-L-manno-nonulosonic acid (CMP-Pse5NAc7Am), which is the first report of Pse modified at C7 with an acetamidino group in Campylobacter, and UDP-2,4-diacetamido-2,4,6-trideoxy-alpha-D-glucopyranose, which is a bacillosamine derivative found in the N-linked proteinglycan. Using this focused metabolomics approach, pseB, pseC, pseF, pseI, and for the first time pseA, pseG, and pseH were found to be directly involved in either the biosynthesis of CMP-Pse5NAc7NAc or CMP-Pse5NAc7Am. In contrast, it was shown that pseD, pseE, Cj1314c, Cj1315c, Cjb1301, Cj1334, Cj1341c, and Cj1342c have no role in the CMP-Pse5NAc7NAc or CMP-Pse5NAc7Am pathways. These results demonstrate the usefulness of this approach for targeting compounds within the bacterial metabolome to assign function to genes, identify metabolic intermediates, and elucidate novel biosynthetic pathways. 相似文献
108.
The O-chain polysaccharide (O-PS) of Bordetella avium was isolated from the lipopolysaccharide by mild acid hydrolysis to remove the lipid A, followed by hydrofluorolysis to remove the lipopolysaccharide core oligosaccharide leaving a residual O-PS for structural analysis. High resolution (1)H and (13)C NMR and MALDI studies showed the O-chain to be a polymer composed of 1,4-linked 2-acetamidino-3-[3-hydroxybutanamido]-2,3-dideoxy-beta-D-glucopyranosyluronic acid residues. 相似文献
109.
Michael FS Brisson JR Larocque S Monteiro M Li J Jacques M Perry MB Cox AD 《Carbohydrate research》2004,339(11):1973-1984
The structures of the core oligosaccharides of the lipopolysaccharides (LPS) from Actinobacillus pleuropneumoniae serotypes 1, 2, 5a and 5b were elucidated. The LPS's were subjected to a variety of degradative procedures. The structures of the purified products were established by monosaccharide and methylation analyses, NMR spectroscopy and mass spectrometry. The following structures for the core oligosaccharides were determined on the basis of the combined data from these experiments. [carbohydrate formula see text] For serotype 1: R is (1S)-GalaNAc-(1-->4,6)-alpha-Gal II-(1-->3)-beta-Gal I-(1-->, and R' is H For serotype 2: R is beta-Glc III-(1-->, and R' is D-alpha-D-Hep V-(1--> For serotypes 5a and 5b: R is H and R' is D-alpha-D-Hep V-(1--> All oligosaccharides elaborated a conserved inner core structure, as illustrated. All sugars were in the pyranose ring form apart from the open-chain N-acetylgalactosamine, the identification of which in the serotype 1 LPS was of interest. 相似文献
110.