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991.
Density and species richness of fungal communities in soils ofFusarium infested and non-infested tomato-growing localities were studied by comparison of rhizoplanes, rhizospheres, and root-free
soils. The rhizosphere soils harbored the highest counts of fungi, followed by root-free soil and rhizoplanes in both localities.
Species richness was high in the rhizosphere and root-free soil but distinctly low in the rhizoplane. The population density
of the zhizosphere and the rhizoplane showed a significant difference between infested and non-infested localities. 相似文献
992.
Abdulrahman T. Saadi C. Caroline Blackwell Stephen D. Essery Mohammed W. Raza Omar R. El Ahmer Doris A.C. MacKenzie Valerie S. James Donald M. Weir Marie M. Ogilvie Robert A. Elton Anthony Busuttil Jean W. Keeling 《FEMS immunology and medical microbiology》1996,16(1):51-59
Abstract Asymptomatic infection due to Bordetella pertussis has been suggested to be one cause of sudden infant death syndrome (SIDS). We examined developmental and environmental factors previously found to affect binding of another toxigenic species, Staphylococcus aureus , to human epithelial cells: expression of the Lewisa antigen; infection with respiratory syncytial virus (RSV); exposure to cigarette smoke; and the inhibitory effect of breast milk on bacterial binding. Binding of two strains of B. pertussis (8002 and 250825) to buccal epithelial cells was significantly reduced by treating the cells with monoclonal antibodies to Lewisa ( P < 0.05) and Lewisx ( P < 0.01) antigens. Both strains bound in significantly greater numbers to cells from smokers compared with cells from non-smokers ( P < 0.05). HEp-2 cells infected with RSV subtypes A or B had higher binding indices for both 8002 ( P < 0.001) and 250825 ( P < 0.01). On RSV-infected cells, there was significantly enhanced binding of monoclonal antibodies to Lewisx ( P < 0.05), CD14 ( P < 0.001) and CD18 ( P < 0.01); and pre-treatment of cells with anti-CD14 or CD18 also significantly reduced binding of both strains of B. pertussis . Pre-treatment of the bacteria with human milk significantly reduced their binding to epithelial cells. The results are discussed in relation to our three-year survey of bacterial carriage among 253 healthy infants, their mothers and local SIDS cases between 1993–1995 and in relation to the change to an earlier immunisation schedule for infants and the recent decline in SIDS in Britain. 相似文献
993.
Ningzhi Xu Omar Coso Daruka Mahadevan Antonio De Blasi Paul K. Goldsmith William F. Simonds J. Silvio Gutkind 《Cellular and molecular neurobiology》1996,16(1):51-59
Summary 1. The noncatalytic domain of Ras-GAP can affect signaling through G protein-coupled receptors by a poorly understood mechanism.
2. In this study, fusion proteins containing elements of the noncatalytic domain ofras-GAP were examined for their ability to bindβγ subunits of heterotrimeric G proteins and phosphotyrosine-containing polypeptides.
3. Our results demonstrate that purifiedβγ dimers associated with bacterially expressed GAP proteins and that this association does not require SH2 or SH3 domains but
is dependent on the presence of the GAP pleckstrin-homology (PH) domain. In contrast, only the SH2 domains are necessary for
binding to tyrosine phosphorylated proteins.
4. These findings raise the possibility that heterotrimeric G proteins might affect functioning ofras-like proteins throughβγ subunits acting on their regulatory molecules. 相似文献
994.
Herman L. De Pooter Muhammad Nor Omar Brigitte A. Coolsaet Niceas M. Schamp 《Phytochemistry》1985,24(1):93-96
The essential oil of A. galanga, a common spice in Malaysia, was prepared from fresh and dried rhizomes and analysed by means of capillary GC and GC/MS. Forty components were identified (only three of which were previously reported), accounting for 83–93% of the oil, depending on its method of preparation. Apart from monoterpenes, monoterpene alcohols and esters, and sesquiterpenes, also methyleugenol, eugenol acetate, chavicol (4-allylphenol) and chavicol acetate were present. This is the first time the latter substance has been reported in nature. Standardization of GC is proposed and tentatively applied towards a more systematic use of the Kováts indices as an aid in the identification of the constituents of essential oils. 相似文献
995.
Abdelghani Iddar Federico Valverde Omar Assobhei Aurelio Serrano Abdelaziz Soukri 《International microbiology》2005,8(4):251-258
The non-phosphorylating glyceraldehyde 3-phosphate dehydrogenase (GAPDHN, NADP+-specific, EC 1.2.1.9) is present in green eukaryotes and some Streptococcus strains. The present report describes the results of activity and immunoblot analyses, which were used to generate the first survey of bacterial GAPDHN distribution in a number of Bacillus, Streptococcus and Clostridium strains. Putative gapN genes were identified after PCR amplification of partial 700-bp sequences using degenerate primers constructed from highly conserved protein regions. Alignment of the amino acid sequences of these fragments with those of known sequences from other eukaryotic and prokaryotic GAPDHNs, demonstrated the presence of conserved residues involved in catalytic activity that are not conserved in aldehyde dehydrogenases, a protein family closely linked to GAPDHNs. The results confirm that the basic structural features of the members of the GAPDHN family have been conserved throughout evolution and that no identity exists with phosphorylating GAPDHs. Furthermore, phylogenetic trees generated from multiple sequence alignments suggested a close relationship between plant and bacterial GAPDHN families. 相似文献
996.
Maria S. Gonzlez Omar J. Rimoldi Rodolfo R. Brenner 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1995,110(4)
The function of Triatoma infestans very-high-density lipoprotein (VHDL) as a free fatty acid transport protein was analyzed. Lipophorin (HDLp) and VHDL are the unique hemolymphatic proteins able to transport free fatty acids (FFA). The transfer of this lipid species between HDLp and VHDL was studied using 14C-palmitic acid-labeled VHDL or 14C-palmitic acid-labeled HDLp as donor substrate and the same unlabeled lipoproteins as acceptor substrate. The VHDL is more effective as acceptor of 14C-FFA from HDLp rather than donor of 14C-FFA to HDLp. When 14C-palmitic acid-labeled VHDL was incubated with either fat body or testicle, it was observed that the 14C-palmitic acid was taken up by both tissues and incorporated into their lipid components. 相似文献
997.
Electron microscope study on the development of ciliary components of the neural epithelium of the chick embryo 总被引:1,自引:0,他引:1
Summary Ciliary development was studied in the cells of the neural canal of chick embryos incubated from 60 hours to 7 days.It was found that centrioles move after the last mitosis to the cell periphery where one of them enters into contact (terminal contact) with the cell membrane; the other centriole remains close by, its axis aligned along the axis of the former.The cell membrane was seen afterwards bulging at the contact point, and the content of the ciliary bud thus formed is only constituted at the beginning of a varied number of vesicles of about 140 Å diameter.The ciliary bud becomes elongated shortly after filaments start becoming organized in the bud matrix.Roughly coinciding with the initiation of filament organization the centrioles move inward and the cilium becomes deeply invaginated in the cell. At the end of ciliary growth the centriole moves again toward the surface and the cilium emerges in the neural canal lumen. 相似文献
998.
Refka Ben Issa Hélène Gautier Guy Costagliola Laurent Gomez 《Entomologia Experimentalis et Applicata》2016,160(2):164-178
Intercropping of companion plants (CPs) that release distinct volatile compounds with horticultural crops has been proposed to improve pest management. Although CP extracts or essential oils have been reported to be efficient in disturbing the settling of insects such as aphids, the effect of using actual CPs remains relatively unknown. Our aim was to screen odorous CP species for their effect on the performance of green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae), when released on adjacent pepper plants. Intercropping was tested in growth chambers using potted plants to avoid root interactions and homogenise the abiotic environment of CPs. Our results indicated that eight CP species—rosemary, African marigold, French marigold, geranium, lavender, basil, chives, and pot marigold—affected aphid performance by reducing the reproductive performance and/or settlement of females. Rosemary followed by African and French marigold was associated with the largest reduction in adult female and nymph number. Chemical analyses indicated that rosemary and French marigold emit specific volatiles. In contrast, four CP species (false yellowhead, thyme, savoury, and peppermint) were not associated with a significant change in aphid performance and emitted a lower diversity of volatiles. This screening of CPs under controlled conditions may be considered as a first step towards the identification of volatiles emitted by actual plants that can affect aphid performance and help the choice of CPs to optimise intercropping strategies. 相似文献
999.
The historical biogeography of the southern group of the sucker genus Moxostoma (Teleostei: Catostomidae) and the colonization of central Mexico
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Rodolfo Pérez‐Rodríguez Omar Domínguez‐Domínguez Adan Fernando Mar‐Silva Ignacio Doadrio Gerardo Pérez‐Ponce de León 《Zoological Journal of the Linnean Society》2016,177(3):633-647
The historical biogeography of the southern group of Moxostoma Rafinesque, 1820, a genus of Nearctic freshwater fishes belonging to the Catostomidae, along its entire distribution in North America was inferred to: (1) determine the biogeographical events responsible for its current pattern of diversity and distribution; (2) correlate the climatic and geologic history of the region with the biogeographical pattern observed; and (3) trace the colonization route into central Mexico and the western Pacific slope drainages. The sequences of mitochondrial cytochrome b and the third intron of the growth hormone were obtained for the members of the southern group and related species of the Catostomidae. Phylogenetic analyses and relaxed molecular clock analyses were performed to determine the relatedness of the species and to estimate divergence times. To uncover biogeographical patterns, a dispersal–extinction–cladogenesis (DEC) analysis was conducted. The phylogenetic analyses were consistent with the historical hydrographic scenario in the region. The divergence times show that the southern group evolved during the Pliocene–Pleistocene. The DEC analyses showed that vicariance and dispersal played an important role in the current distribution patterns of the lineages in central Mexico, and allow us to trace an independent route of colonization from the northern areas of North America into central Mexico. 相似文献
1000.
Omar M. Amin R. Paul Evans Magloire Boungou Richard Heckmann 《Systematic parasitology》2016,93(2):173-191