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51.
Bacterial glycogen is a polyglucose storage compound that is thought to prolong viability during stationary phase. However, a specific role for glycogen has not been determined. We have characterized SMEG53, a temperature-sensitive mutant of Mycobacterium smegmatis that contains a mutation in glgE, encoding a putative glucanase. This mutation causes exponentially growing SMEG53 cells to stop growing at 42 degrees C in response to high levels of glycogen accumulation. The mutation in glgE is also associated with an altered growth rate and colony morphology at permissive temperatures; the severity of these phenotypes correlates with the amount of glycogen accumulated by the mutant. Suppression of the temperature-sensitive phenotype, via a decrease in glycogen accumulation, is mediated by growth in certain media or multicopy expression of garA. The function of GarA is unknown, but the presence of a forkhead-associated domain suggests that this protein is a member of a serine-threonine kinase signal transduction pathway. Our results suggest that in M. smegmatis glycogen is continuously synthesized and then degraded by GlgE throughout exponential growth. In turn, this constant recycling of glycogen controls the downstream availability of carbon and energy. Thus, in addition to its conventional storage role, glycogen may also serve as a carbon capacitor for glycolysis during the exponential growth of M. smegmatis. 相似文献
52.
A report of the Biochemical Society/Wellcome Trust meeting 'Protein Evolution - Sequences, Structures and Systems', Hinxton,
UK, 26-27 January 2009. 相似文献
53.
Chu GH Gu M Cassel JA Belanger S Stabley GJ DeHaven RN Conway-James N Koblish M Little PJ DeHaven-Hudkins DL Dolle RE 《Bioorganic & medicinal chemistry letters》2006,16(3):645-648
A novel series of phenylamino acetamide derivatives was synthesized. These amides were shown to be potent and selective kappa opioid receptor agonists. 相似文献
54.
Widiez T Hartman TG Dudai N Yan Q Lawton M Havkin-Frenkel D Belanger FC 《Plant molecular biology》2011,76(6):475-488
Caffeoyl CoA O-methyltransferases (OMTs) have been characterized from numerous plant species and have been demonstrated to be involved in
lignin biosynthesis. Higher plant species are known to have additional caffeoyl CoA OMT-like genes, which have not been well
characterized. Here, we identified two new caffeoyl CoA OMT-like genes by screening a cDNA library from specialized hair cells
of pods of the orchid Vanilla planifolia. Characterization of the corresponding two enzymes, designated Vp-OMT4 and Vp-OMT5, revealed that in vitro both enzymes preferred
as a substrate the flavone tricetin, yet their sequences and phylogenetic relationships to other enzymes are distinct from
each other. Quantitative analysis of gene expression indicated a dramatic tissue-specific expression pattern for Vp-OMT4, which was highly expressed in the hair cells of the developing pod, the likely location of vanillin biosynthesis. Although
Vp-OMT4 had a lower activity with the proposed vanillin precursor, 3,4-dihydroxybenzaldehyde, than with tricetin, the tissue
specificity of expression suggests it may be a candidate for an enzyme involved in vanillin biosynthesis. In contrast, the
Vp-OMT5 gene was mainly expressed in leaf tissue and only marginally expressed in pod hair cells. Phylogenetic analysis suggests
Vp-OMT5 evolved from a cyanobacterial enzyme and it clustered within a clade in which the sequences from eukaryotic species
had predicted chloroplast transit peptides. Transient expression of a GFP-fusion in tobacco demonstrated that Vp-OMT5 was
localized in the plastids. This is the first flavonoid OMT demonstrated to be targeted to the plastids. 相似文献
55.
Understanding the genetic variation within a parasitic species is crucial to implementing successful control programs and preventing the dispersal of drug resistance alleles. We examined the population genetics and structure of canine heartworm (Dirofilaria immitis) by developing a panel of 11 polymorphic microsatellite loci for this abundant parasite. In total, 192 individual nematodes were opportunistically sampled from 9 geographic regions in the United States and Mexico and genotyped. Population genetic analyses indicate the presence of 4 genetic clusters. The canine heartworm samples used in this study were characterized by low heterozygosity, with eastern and central North America experiencing high levels of reciprocal gene flow. Geographic barriers impede the movement of vectors and infected hosts west of the Rocky Mountains and south of the Central Mexican Plateau. This, combined with corridors of contiguous habitat, could influence the spread of drug resistance alleles. 相似文献
56.
Dele Ogunremi John Devenish Kingsley Amoako Hilary Kelly Andrée Ann Dupras Sebastien Belanger Lin Ru Wang 《BMC genomics》2014,15(1)
Background
There is a need to characterize genomes of the foodborne pathogen, Salmonella enterica serovar Enteritidis (SE) and identify genetic information that could be ultimately deployed for differentiating strains of the organism, a need that is yet to be addressed mainly because of the high degree of clonality of the organism. In an effort to achieve the first characterization of the genomes of SE of Canadian origin, we carried out massively parallel sequencing of the nucleotide sequence of 11 SE isolates obtained from poultry production environments (n = 9), a clam and a chicken, assembled finished genomes and investigated diversity of the SE genome.Results
The median genome size was 4,678,683 bp. A total of 4,833 chromosomal genes defined the pan genome of our field SE isolates consisting of 4,600 genes present in all the genomes, i.e., core genome, and 233 genes absent in at least one genome (accessory genome). Genome diversity was demonstrable by the presence of 1,360 loci showing single nucleotide polymorphism (SNP) in the core genome which was used to portray the genetic distances by means of a phylogenetic tree for the SE isolates. The accessory genome consisted mostly of previously identified SE prophage sequences as well as two, apparently full- sized, novel prophages namely a 28 kb sequence provisionally designated as SE-OLF-10058 (3) prophage and a 43 kb sequence provisionally designated as SE-OLF-10012 prophage.Conclusions
The number of SNPs identified in the relatively large core genome of SE is a reflection of substantial diversity that could be exploited for strain differentiation as shown by the development of an informative phylogenetic tree. Prophage sequences can also be exploited for SE strain differentiation and lineage tracking. This work has laid the ground work for further studies to develop a readily adoptable laboratory test for the subtyping of SE.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-713) contains supplementary material, which is available to authorized users. 相似文献57.
Summary Zygotes of the brown algaFucus distichus undergo a series of intracellular changes resulting in the establishment of a polar growth axis prior to the first embryonic cell division. In order to examine the dynamics of membrane recycling which occur in the zygote during polar growth of the rhizoid, we probed living Fucus zygotes with the vital stain FM4-64, N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylammo)phenyl)hexatrienyl)pyridinium dibromide. In newly fertilized, spherical zygotes, FM4-64 staining is symmetric and predominantly in the perinuclear region which is rich in endoplasmic reticulum, Golgi, and vacuolar membranes. As rhizoid or tip growth is initiated, this population of stained membranes becomes asymmetrically redistributed, concentrating at the rhizoid tip and extending centrally to the perinuclear region. This asymmetric localization is maintained in the zygote throughout polar growth of the rhizoid and during karyokinesis. Subsequently, FM4-64 staining also begins to accumulate in a central location between the daughter nuclei. As cytokinesis proceeds, this region of stain expands laterally from this central location, perpendicular to the plane of polar rhizoid outgrowth. The staining pattern thus delineates the formation of a cell plate, similar spatially to the accumulation of nascent plate membranes of higher plants. Treatment of Fucus zygotes with brefeldin-A inhibits both asymmetric growth of the rhizoid and formation of a new cell plate. These data suggest that inF. distichus FM4-64 is labeling a Golgi-derived membrane fraction that appears to be recycling between the site of tip growth, perinuclear region, and new cell plate.Abbreviations AF
after fertilization
- ASW
artificial seawater
- BFA
brefeldin A
- ER
endoplasmic reticulum
- FM4-64
N-(3-triethylam-moniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)pyridinium dibromide 相似文献
58.
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