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51.
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In 59 samples of periphyton and phytoplankton collected in 2002 - 2003 from the Nahal Qishon (Qishon River), northern Israel, we found 178 species from seven divisions of algae and cyanoprocaryotes. Diatoms, clorophytes, and cyanoprocaryotes prevail. Nitzschia and Navicula (Bacillariophyta) are the most abundant. Most of the species are cosmopolitan or widespread, except Lagynion janei (Chrysophyta), which is endemic for the Mediterranean Realm. About 17% of species (26) are new for Israel and five of them represent the first recorded genera: Crinalium endophyticum Crow, Actinocyclus normanii (Gregory) Hustedt, Rhizoclonium hieroglyphicum (Agardh) Kütz (Chlorophyta), Lagynion janei Bourelly, and Stylococcus aureus Chodat. Most of them come from a rare riverine assemblage with red alga Audouinella pygmea, as well as from the estuarine assemblage. Alkaliphiles predominate among the indicators of acidity, with few acidophiles confined to the communities under the impact of industrial wastes. Among the indicators of salinity, most numerous are the oligohalobien-indifferents and species adapted to a moderate salinity level. The relative species richness of ecological groups and the indices of saprobity are correlated with changes in conductivity, pH, and N-nitrate concentration. Indicators of organic pollution fall in the range of betameso- to alfamesosaprobic self-purification grades. Our studies show ecological significance of the Nahal Qishon as a model for a strongly disturbed aquatic ecosystem in the coastal zone of eastern Mediterranean. 相似文献
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SS Padala MA Kiresur A Ananthaneni VS Guduru HK Puneeth B Bhavana 《Biotechnic & histochemistry》2013,88(5):336-339
Toto bodies are eosinophilic structures that resemble the cells of the superficial cell layer of the oral epithelium. Toto bodies commonly are associated with inflammatory gingival and other mucosal lesions including pyogenic granuloma, irritational fibroma, epulis fissuratum, peripheral giant cell granuloma and inflammatory hyperplastic gingivitis. We evaluated staining characteristics of Toto bodies to establish their origin and to identify their significance in lesions. We investigated pyogenic granuloma, fibroma and leukoplakia with epithelium that exhibited Toto bodies after hematoxylin and eosin (staining. Sections were stained with Alcian blue, periodic acid-Schiff and Ayoub-Shklar stains to evaluate staining intensity and distribution. More Toto bodies were found in pyogenic granuloma than in fibroma and leukoplakia. PAS and Alcian blue staining exhibited mild intensity and did not establish the origin of Toto bodies. High staining intensity and diffuse distribution of stain was observed using Ayoub-Shklar staining, which indicated that Toto bodies originate from keratin. 相似文献
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Multiple-copy cluster-type organization and evolution of genes encoding O-methyltransferases in the apple 总被引:1,自引:0,他引:1
Plant O-methyltransferases (OMTs) play important roles in secondary metabolism. Two clusters of genes coding for caffeic acid OMT (COMT) have been identified in the apple genome. Three genes from one cluster and two genes from another cluster were isolated. These five genes encoding COMT, designated Mdomt1-Mdomt5 (GenBank accession nos. DQ886018-DQ886022), were distinguished by a (CT)(n) microsatellite in the 5'-UTR and two transposon-like sequences present in the promoter region and intron 1, respectively. The transposon-like sequence in intron 1 unambiguously traced the five Mdomt genes in the apple to a common ancestor. The ancestor must have undergone an initial duplication generating two progenitors, and this was followed by further duplication of these progenitors resulting in the two clusters identified in this study. The distal regions of the transposon-like sequences in promoter regions of Mdomt genes are capable of forming palindromic hairpin-like structures. The hairpin formation is likely responsible for nucleotide sequence differences observed in the promoter regions of these genes as it plays a destabilizing role in eukaryotic chromosomes. In addition, the possible mechanism of amplification of Mdomt genes in the apple genome is also discussed. 相似文献
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Muhammad Awais Khan Yuepeng Han Youfu Frank Zhao Michela Troggio Schuyler S. Korban 《PloS one》2012,7(11)
Genetic maps serve as frameworks for determining the genetic architecture of quantitative traits, assessing structure of a genome, as well as aid in pursuing association mapping and comparative genetic studies. In this study, a dense genetic map was constructed using a high-throughput 1,536 EST-derived SNP GoldenGate genotyping platform and a global consensus map established by combining the new genetic map with four existing reliable genetic maps of apple. The consensus map identified markers with both major and minor conflicts in positioning across all five maps. These major inconsistencies among marker positions were attributed either to structural variations within the apple genome, or among mapping populations, or genotyping technical errors. These also highlighted problems in assembly and anchorage of the reference draft apple genome sequence in regions with known segmental duplications. Markers common across all five apple genetic maps resulted in successful positioning of 2875 markers, consisting of 2033 SNPs and 843 SSRs as well as other specific markers, on the global consensus map. These markers were distributed across all 17 linkage groups, with an average of 169±33 marker per linkage group and with an average distance of 0.70±0.14 cM between markers. The total length of the consensus map was 1991.38 cM with an average length of 117.14±24.43 cM per linkage group. A total of 569 SNPs were mapped onto the genetic map, consisting of 140 recombinant individuals, from our recently developed apple Oligonucleotide pool assays (OPA). The new functional SNPs, along with the dense consensus genetic map, will be useful for high resolution QTL mapping of important traits in apple and for pursuing comparative genetic studies in Rosaceae. 相似文献
58.
In this study, we attempted to understand the role of an orphan gene amyR in Erwinia amylovora, a functionally conserved ortholog of ybjN in Escherichia coli, which has recently been characterized. Amylovoran, a high molecular weight acidic heteropolymer exopolysaccharide, is a virulent factor of E. amylovora. As reported earlier, amylovoran production in an amyR knockout mutant was about eight-fold higher than that in the wild type (WT) strain of E. amylovora. When a multicopy plasmid containing the amyR gene was introduced into the amyR mutant or WT strains, amylovoran production was strongly inhibited. Furthermore, amylovoran production was also suppressed in various amylovoran-over-producing mutants, such as grrSA containing multicopies of the amyR gene. Consistent with amylovoran production, an inverse correlation was observed between in vitro expression of amyR and that of amylovoran biosynthetic genes. However, both the amyR knockout mutant and over-expression strains showed reduced levan production, another exopolysaccharide produced by E. amylovora. Virulence assays demonstrated that while the amyR mutant was capable of inducing slightly greater disease severity than that of the WT strain, strains over-expressing the amyR gene did not incite disease on apple shoots or leaves, and only caused reduced disease on immature pear fruits. Microarray studies revealed that amylovoran biosynthesis and related membrane protein-encoding genes were highly expressed in the amyR mutant, but down-regulated in the amyR over-expression strains in vitro. Down-regulation of amylovoran biosynthesis genes in the amyR over-expression strain partially explained why over-expression of amyR led to non-pathogenic or reduced virulence in vivo. These results suggest that AmyR plays an important role in regulating exopolysaccharide production, and thus virulence in E. amylovora. 相似文献
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Malnoy M Xu M Borejsza-Wysocka E Korban SS Aldwinckle HS 《Molecular plant-microbe interactions : MPMI》2008,21(4):448-458
The Vf locus, originating from the crabapple species Malus floribunda 821, confers resistance to five races of the fungal pathogen Venturia inaequalis, the causal agent of apple scab disease. Previously, a cluster of four receptor-like genes, Vfa1, Vfa2, Vfa3, and Vfa4, was identified within the Vf locus. Because the amino-acid sequence of Vfa3 is truncated, it was deemed nonfunctional. In this study, each of the three full-length Vfa genes was introduced into a plant cloning vector, pCAMBIA2301, and used for Agrobacterium-mediated transformation of two apple cultivars, Galaxy and McIntosh, to assess functionality of these genes and to characterize their roles in resistance to V. inaequalis. Transformed apple lines carrying each of Vfa1, Vfa2, or Vfa4 were developed, analyzed for the presence of the transgene using polymerase chain reaction and Southern blotting, and assayed for resistance to apple scab following inoculation with V. inaequalis. Transformed lines expressing Vfa4 were found to be susceptible to apple scab, whereas those expressing either Vfa1 or Vfa2 exhibited partial resistance to apple scab. Based on Western blot analysis as well as microscopic analysis of plant resistance reactions, the roles of Vfa1 and Vfa2 in apple scab disease resistance response are discussed. 相似文献