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61.
Delany I.R. Walsh U.F. Ross I. Fenton A.M. Corkery D.M. O'Gara F. 《Plant and Soil》2001,232(1-2):195-205
Pseudomonas fluorescens F113 is an effective biocontrol agent against Pythium ultimum, the causative agent of damping-off of sugarbeet seedlings. Biocontrol is mediated via the production of the anti-fungal metabolite 2,4-diacetylphloroglucinol (Phl). A genetic approach was used to further enhance the biocontrol ability of F113. Two genetically modified (GM) strains, P. fluorescens F113Rif (pCU8.3) and P. fluorescens F113Rif (pCUP9), were developed for enhanced Phl production and assessed for biocontrol efficacy and impact on sugarbeet in microcosm experiments. The multicopy plasmid pCU8.3 contains the biosynthetic genes (phlA, C, B and D) and the putative permease gene (phlE) of F113 cloned into the rhizosphere stable plasmid pME6010, independent of external promoters. The plasmid pCUP9 consists of the Phl biosynthetic genes cloned downstream of the constitutive Plac promoter in pBBR1MCS. Introduction of pCU8.3 and pCUP9 into P. fluorescens F113 significantly altered the kinetics of Phl biosynthesis when grown in SA medium. A significant and substantial increase in Phl production by the GM strains was observed in the early logarithmic phase and stationary phase of growth compared with the wild-type strain. In microcosm, the two Phl overproducing strains proved to be as effective at controlling damping-off disease as the proprietary fungicide treatment, indicating the potential of genetic modification for plant disease control. 相似文献
62.
The extent of polylactosamine glycosylation of MDCK LAMP-2 is determined by its Golgi residence time 总被引:2,自引:1,他引:1
The increased polylactosamine glycosylation of LAMP-2 in MDCK cells
cultured for 1 day relative to cells cultured for 3 days has been
correlated with its slower rate of Golgi transit (Nabi and Rodriguez-
Boulan, 1993, Mol. Biol. Cell., 4, 627-635). To determine if the
differential polylactosamine glycosylation of LAMP-2 is a consequence of
glycosyltransferase expression levels, the activities of beta1- 6GlcNAc-TV,
beta1-3GlcNAc-T(i), beta1-2GlcNAc-TI, beta1, 4Gal-T, alpha2- 6sialyl-T, and
alpha2-3sialyl-T were assayed and no significant differences in the
activities of these enzymes in 1 and 3 day cell extracts were detected.
During MDCK epithelial polarization, the Golgi apparatus undergoes
morphological changes and apiconuclear Golgi networks were more evident in
3 day cells. Treatment with nocodazole disrupted Golgi networks and
generated numerous Golgi clusters in both 1 day and 3 day cells. In the
presence of nocodazole the differential migration of LAMP-2 in 1 and 3 day
MDCK cells was maintained and could be eliminated by treatment with
endo-beta-galactosidase, indicating that gross Golgi morphology did not
influence the extent of LAMP-2 polylactosamine glycosylation. Nocodazole
treatment did, however, result in the faster migration of LAMP-2 which was
not due to modification of core N-glycans as the precursor form of the
glycoprotein migrated with an identical molecular size. Following
incubation at 20 degrees C, which prevents the exit of proteins from the
trans-Golgi network, the molecular size of LAMP-2 increased to a similar
extent in both 1 and 3 day MDCK cells. Extending the time of incubation at
20 degrees C did not influence the size of LAMP-2, demonstrating that its
glycosylation is modified not by its retention within the Golgi but rather
by its equivalent slower Golgi passage at the lower temperature in both 1
and 3 day cells. An identical effect was observed in nocodazole treated
cells, demonstrating that Golgi residence time determines the extent of
LAMP-2 polylactosamine glycosylation, even in isolated Golgi clusters.
相似文献
63.
Vascular endothelial growth factors (VEGFs) are a family of secreted polypeptides with a highly conserved receptor-binding
cystine-knot structure similar to that of the platelet-derived growth factors. VEGF-A, the founding member of the family,
is highly conserved between animals as evolutionarily distant as fish and mammals. In vertebrates, VEGFs act through a family
of cognate receptor kinases in endothelial cells to stimulate blood-vessel formation. VEGF-A has important roles in mammalian
vascular development and in diseases involving abnormal growth of blood vessels; other VEGFs are also involved in the development
of lymphatic vessels and disease-related angiogenesis. Invertebrate homologs of VEGFs and VEGF receptors have been identified
in fly, nematode and jellyfish, where they function in developmental cell migration and neurogenesis. The existence of VEGF-like
molecules and their receptors in simple invertebrates without a vascular system indicates that this family of growth factors
emerged at a very early stage in the evolution of multicellular organisms to mediate primordial developmental functions. 相似文献
64.
Second report on chicken genes and chromosomes 2005 总被引:1,自引:0,他引:1
Schmid M Nanda I Hoehn H Schartl M Haaf T Buerstedde JM Arakawa H Caldwell RB Weigend S Burt DW Smith J Griffin DK Masabanda JS Groenen MA Crooijmans RP Vignal A Fillon V Morisson M Pitel F Vignoles M Garrigues A Gellin J Rodionov AV Galkina SA Lukina NA Ben-Ari G Blum S Hillel J Twito T Lavi U David L Feldman MW Delany ME Conley CA Fowler VM Hedges SB Godbout R Katyal S Smith C Hudson Q Sinclair A Mizuno S 《Cytogenetic and genome research》2005,109(4):415-479
65.
66.
Samples of tail muscle from 32 American alligators (Alligator mississippiensis) in Florida were analyzed for contaminant concentrations to provide preliminary information on the potential public health hazard of meat consumption. Detectable levels were found for eight metals; copper, zinc, iron, chromium, mercury, lead, cadmium and arsenic. Mean residue was highest for mercury (geometric mean = 0.61 ppm). DDE, DDD, DDT, dieldrin, heptachlor epoxide, lindane, and PCB's were found. Mean residue concentrations were compared by lake. Alligators appeared to be suitable monitors of environmental pollution. Concentrations of contaminants found in these animals probably pose little threat to public health. However, recommendations must await analysis of larger sample sizes and information on amount and frequency of meat consumption. Alligators killed for human consumption should continue to be monitored for contaminant residues. 相似文献
67.
68.
Jeb P. Owen Mary E. Delany Arthur A. Bickford 《International journal for parasitology》2009,39(7):789-799
Vertebrate immune responses to ectoparasites influence pathogen transmission and host fitness costs. Few studies have characterized natural immune responses to ectoparasites and resultant fitness effects on the ectoparasite. These are critical gaps in understanding vertebrate-ectoparasite interaction, disease ecology and host-parasite co-adaptation. This study focused on an ectoparasite of birds—the northern fowl mite (NFM) (Ornithonyssus sylviarum). Based on prior evidence that chickens develop resistance to NFM, these experiments tested two hypotheses: (i) skin inflammation blocks mite access to blood, impairing development, reproduction and survival; and (ii) host immunogenetic variation influences the inflammatory response and subsequent effects on the ectoparasite. On infested hosts, histology of skin inflammation revealed increased epidermal cell number and size, immigration of leukocytes and deposition of serous exudates on the skin surface. Survival of adult mites and their offspring decreased as the area of skin inflammation increased during an infestation. Inflammation increased the distance to blood vessels beyond the length of mite mouthparts (100-160 μm) and prevented protonymphs and adults from reaching a blood source. Consequently, protonymphs could not complete development, evidenced by a significant inverse relationship between inflammation and protonymph feeding success, as well as an increasing protonymph/adult ratio. Adult females were unable to feed and reproduce, indicated by an inverse relationship between inflammation and egg production, and decreasing female/juvenile ratio. These combined impacts of host inflammation reversed NFM population growth. Intensity of inflammation was influenced by the genotype of the major histocompatibility complex (MHC), supporting previous research that linked these immunological loci with NFM resistance. Overall, these data provide a model for a mechanism of avian resistance to an ectoparasitic arthropod and the fitness costs to the parasite of that host defense. 相似文献
69.
70.
The chicken coloboma mutation exhibits features similar to human congenital developmental malformations such as ocular coloboma, cleft-palate, dwarfism, and polydactyly. The coloboma-associated region and encoded genes were investigated using advanced genomic, genetic, and gene expression technologies. Initially, the mutation was linked to a 990 kb region encoding 11 genes; the application of the genetic and genomic tools led to a reduction of the linked region to 176 kb and the elimination of 7 genes. Furthermore, bioinformatics analyses of capture array-next generation sequence data identified genetic elements including SNPs, insertions, deletions, gaps, chromosomal rearrangements, and miRNA binding sites within the introgressed causative region relative to the reference genome sequence. Coloboma-specific variants within exons, UTRs, and splice sites were studied for their contribution to the mutant phenotype. Our compiled results suggest three genes for future studies. The three candidate genes, SLC30A5 (a zinc transporter), CENPH (a centromere protein), and CDK7 (a cyclin-dependent kinase), are differentially expressed (compared to normal embryos) at stages and in tissues affected by the coloboma mutation. Of these genes, two (SLC30A5 and CENPH) are considered high-priority candidate based upon studies in other vertebrate model systems. 相似文献