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131.
A. M. Crawford K. G. Dodds A. J. Ede C. A. Pierson G. W. Montgomery H. G. Garmonsway A. E. Beattie K. Davies J. F. Maddox S. W. Kappes R. T. Stone T. C. Nguyen J. M. Penty E. A. Lord J. E. Broom J. Buitkamp W. Schwaiger J. T. Epplen P. Matthew M. E. Matthews D. J. Hulme K. J. Beh R. A. McGraw C. W. Beattie 《Genetics》1995,140(2):703-724
We report the first extensive ovine genetic linkage map covering 2070 cM of the sheep genome. The map was generated from the linkage analysis of 246 polymorphic markers, in nine three-generation fullsib pedigrees, which make up the AgResearch International Mapping Flock. We have exploited many markers from cattle so that valuable comparisons between these two ruminant linkage maps can be made. The markers, used in the segregation analyses, comprised 86 anonymous microsatellite markers derived from the sheep genome, 126 anonymous microsatellites from cattle, one from deer, and 33 polymorphic markers of various types associated with known genes. The maximum number of informative meioses within the mapping flock was 222. The average number of informative meioses per marker was 140 (range 18-209). Linkage groups have been assigned to all 26 sheep autosomes. 相似文献
132.
Induction of microbial genes for pathogenesis and symbiosis by chemicals from root border cells. 总被引:6,自引:0,他引:6
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Reporter strains of soil-borne bacteria were used to test the hypothesis that chemicals released by root border cells can influence the expression of bacterial genes required for the establishment of plant-microbe associations. Promoters from genes known to be activated by plant factors included virE, required for Agrobacterium tumefaciens pathogenesis, and common nod genes from Rhizobium leguminosarum bv viciae and Rhizobium meliloti, required for nodulation of pea (Pisum sativum) and alfalfa (Medicago sativum), respectively. Also included was phzB, an autoinducible gene encoding the biosynthesis of antibiotics by Pseudomonas aureofaciens. The virE and nod genes were activated to different degrees, depending on the source of border cells, whereas phzB activity remained unaffected. The homologous interaction between R. leguminosarum bv viciae and its host, pea, was examined in detail. Nod gene induction by border cells was dosage dependent and responsive to environmental signals. The highest levels of gene induction by pea (but not alfalfa) border cells occurred at low temperatures, when little or no bacterial growth was detected. Detached border cells cultured in distilled water exhibited increased nod gene induction (ini) in response to signals from R. leguminosarum bv viciae. 相似文献
133.
Fungal Colonization of Air Filters and Insulation in a Multi-Story Office Building: Production of Volatile Organics 总被引:1,自引:0,他引:1
D.G. Ahearn S.A. Crow R.B. Simmons D.L. Price S.K. Mishra D.L. Pierson 《Current microbiology》1997,35(5):305-308
Secondary air filters in the air-handling units on four floors of a multi-story office building with a history of fungal
colonization of insulation within the air distribution system were examined for the presence of growing fungi and production
of volatile organic compounds. Fungal mycelium and conidia of Cladosporium and Penicillium spp. were observed on insulation from all floors and both sides of the air filters from one floor. Lower concentrations of
volatile organics were released from air filter medium colonized with fungi as compared with noncolonized filter medium. However,
the volatiles from the colonized filter medium included fungal metabolites such as acetone and a carbonyl sulfide-like compound
that were not released from noncolonized filter medium. The growth of fungi in air distribution systems may affect the content
of volatile organics in indoor air.
Received: 2 June 1997 / Accepted: 13 June 1997 相似文献
134.
Current phylogenetic tree reconstruction methods assume that there is a
single underlying tree topology for all sites along the sequence. The
presence of mosaic sequences due to recombination violates this assumption
and will cause phylogenetic methods to give misleading results due to the
imposition of a single tree topology on all sites. The detection of mosaic
sequences caused by recombination is therefore an important first step in
phylogenetic analysis. A graphical method for the detection of
recombination, based on the least squares method of phylogenetic
estimation, is presented here. This method locates putative recombination
breakpoints by moving a window along the sequence. The performance of the
method is assessed by simulation and by its application to a real data set.
相似文献
135.
We used the repetitive character of transposable elements to isolate a
non-LTR retrotransposon in Drosophila subobscura. bilbo, as we have called
it, has homology to TRIM and LOA elements. Sequence analysis showed a 5'
untranslated region (UTR), an open reading frame (ORF) with no RNA-binding
domains, a downstream ORF that had structural homology to that of the I
factor, and, finally, a 3' UTR which ended in several 5-nt repeats. The
results of our phylogenetic and structural analyses shed light on the
evolution of Drosophila non-LTR retrotransposons and support the hypothesis
that an ancestor of these elements was structurally complex.
相似文献
136.
Green-fluorescent protein fusions for efficient characterization of nuclear targeting 总被引:16,自引:0,他引:16
Robert J. Grebenok Elizabeth Pierson Georgina M. Lambert Fang-Cheng Gong Claudio L. Afonso Ruth Haldeman-Cahill James C. Carrington David W. Galbraith 《The Plant journal : for cell and molecular biology》1997,11(3):573-586
The green-fluorescent protein (GFP) from Aequorea victoria has been shown to be a convenient and flexible reporter molecule within a variety of eukaryotic systems, including higher plants. It is particularly suited for applications in vivo, since the mechanism of fluorophore formation involves an intramolecular autoxidation and does not require exogenous co-factors. Unlike standard histochemical procedures of fixation and staining required for analysis of the cellular or tissue-specific expression of other popular reporter molecules, such as the β-glucuronidase (GUS) marker, analysis of GFP can be done in living cells with no specific pretreatments. This implies that GFP might also be particularly suited for studies of intracellular protein targeting. In this paper, the use of GUS is compared with that of GFP for the analysis of nuclear targeting in tobacco. A novel oligopeptide motif from a tobacco protein is described which confers nuclear localization of GUS. The use of this oligopeptide and two from potyviral proteins to target GFP to the nucleus is examined. An essential modification of GFP is described, which specifically increases its molecular weight to eliminate its passive penetration into the nucleus. Three examples of the targeting of these enlarged GFP molecules to the nucleus are illustrated. GFP, in combination with confocal microscopy, offers significant advantages over traditional methods of studying nuclear targeting. 相似文献
137.
Variation of physico-chemical parameters along a river transect through the Okavango Delta,Botswana 总被引:1,自引:0,他引:1
The Okavango Delta depends on water quantity and quality to sustain its ecosystem services. Whereas many studies have been carried out on its hydrology, few have been done on water quality in the delta. Water pH, electrical conductivity (EC), dissolved oxygen (DO), turbidity, total suspended solids (TSS) and dissolved organic carbon (DOC) were monitored at 10 sites along the Okavango–Boro–Thamalakane–Lake Ngami system almost fortnightly from June 2008 to June 2010. Water quality in the delta was generally good, despite high evapotranspiration rates which would normally produce very saline waters. Electrical conductivity and water temperature increased with distance from Mohembo to Lake Ngami, the former most likely due to evapoconcentration. In contrast, pH, DO, turbidity and TSS decreased with distance from Mohembo to Boro at the lower end of the seasonal floodplain, before increasing again to Lake Ngami. Dissolved oxygen and TSS most likely declined due to biological uptake and particle sedimentation, respectively. Strong and significant relationships were observed between TSS and turbidity and between DOC and EC, indicating that turbidity and EC could be useful proxies for routine estimations of TSS and DOC, respectively, in the delta. 相似文献
138.
The suitability of using macroinvertebrates as bioindicators of stream water quality was tested in the Mkondoa River in an agricultural area at Kilosa, using the rapid bioassessment protocol. The family biotic index (FBI) showed marked variation in water quality along the stream from values ranging from 4.1 to 5.0 in the upstream reaches, indicating good water quality, 5.3 to 5.5 in the mid-reaches and 6.0 to 6.5 in the lower reaches. The water quality index (WQI) indicated that water quality was fair (77 ± 0.98) in the upstream reach of the Mkondoa, marginal (55 ± 0.86) in the midstream reach and poor (33 ± 0.45) in the downstream reach. There were significant relationships between biological oxygen demand and dissolved oxygen and the occurrence of specific taxa, mainly Chironomus and Caenis. Significant changes in macroinvertebrate abundance were mostly related to changes in water quality. As in other parts of the world, macroinvertebrate communities proved to be good biological indicators of water quality and they should be used as bioindicators in long-term monitoring of this river. 相似文献
139.
Summary Double labeling with fluorescent probes showed that in the cortical cytoplasm of pollen tubes ofNicotiana tabacum andLilium longiflorum, the microtubules and actin filaments co-localize for the most part. They displayed complex net-axial or helical distributions. They structural association of microtubules and actin filaments implies a functional relationship with respect to organelle movement and/or the organization of the cortical cytoplasm and cell surface.Abbreviations EGTA
ethyleneglycol-bis-(-aminoethylether)-N,N,N,N-tetra-acetic acid
- FITC
fluoresceine iso-thiocyanate 相似文献
140.