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841.
Incubation of pneumococci in a CO(2) environment decreases the zone sizes produced by optochin discs, with the result that pneumococcal-like organisms require further study.  相似文献   
842.
843.
The protection of apples against damage by the codling moth,Laspeyresia pomonella (L.), by applications of the granulosis virus ofL. pomonella was assessed in apple orchard tests at 4 locations in Canada in 1974–1978. Sprays containing 3×109 to 4×1010 granules/litre, applied 2 or 3 times per generation of codling moth larvae, reduced injury to apples by 44 to 85% compared to reductions of 72 to 98% by applications of azinphos-methyl or phosmet. Applications of the virus did not reduce numbers of arthropods predaceous on pest insects and mites.
Résumé L'efficacité de la protection des pommes contre le carpocapse,Laspeyresia pomonella (L.), par des applications du virus de la granulose deL. pomonella a été évaluée par des assais dans 4 vergers du Canada entre 1974 et 1978. Des pulvérisations contenant de 3×109 à 4×1010 granules/litre, appliquées 2 ou 3 fois par génération de larves du carpocapse des pommes, ont réduit les dommages aux pommes de 44 à 85% comparé à des réductions de 72 à 98% obtenues avec des pulvérisations d'azinphos-méthyl ou de phosmet. Les applications de virus n'ont pas réduit les populations d'arthropodes prédateurs d'insectes nuisibles et d'acariens.
  相似文献   
844.
845.
An in vivo ferret model was used to study the association of Staphylococcus aureus with specific tissues of the nasal cavity in both control and influenza A virus-infected animals. Ferrets were inoculated intranasally with various doses of influenza A3/Hong Kong/1/68 virus. On Days 2, 5, 9 and 14, four or five virus-inoculated and two uninoculated controls were challenged intranasally with a 1-ml volume of radiolabeled S. aureus (3 mg dry wt), a clinical isolate of low passage history. Ferrets were allowed to clear the staphylococci in vivo for 60 to 90 min before sacrifice. The animals were anesthetized, exsanguinated, and decapitated, and the lower jaw was removed. The nasal fossae were exposed by dissection and turbinates from the left nasal fossa were used for virus isolation. The median septum and tissues from the right nasal fossa, which included vestibule and anterior and posterior turbinates, were harvested and processed for radioassay. The percentage of recoverable staphylococci from virus-infected ferrets (Days 2 and 5) was greater than or equal to 10-fold higher compared with controls and animals infected with suboptimal doses of virus; greater than or equal to 76% of the recoverable staphylococci, whether from controls or virus-infected animals, was associated with the anterior turbinates. Histologic examination of the anterior turbinates from virus-infected ferrets, particularly on Days 2 and 5 postexposure to virus, showed that the staphylococci were adhering to desquamating respiratory epithelial cells. In contrast, the anterior turbinates from control ferrets uninoculated with virus and posterior turbinates from both control and virus-infected animals showed no evidence of bacteria adhering to host cells; instead, the staphylococci were found in association with the mucus gel layer of respiratory mucosa. Examination of vestibular tissue showed staphylococci in association with cells of the stratum granulosum in both virus-infected and control animals. Results of this study suggest that the early events of S. aureus interaction with different sites of ferret nasal tissues are effected by different mechanisms, and that the interaction is significantly enhanced by virus-infection.  相似文献   
846.
Vapors of mercury and iodine induce abscission in Coleus explantsand color-ripening in immature bananas. Their effects on abscissionare antagonized by an auxin, anaphthaleneacetic acid, and bycarbon dioxide. Alkyl derivatives of mercury and iodine areless active than the parent element, a situation parallel tothe reduced activity of the homologs (alkyl derivatives) ofethylene and acetylene. Chemical differences between the elements and olefins precludea direct ethylenelike effect. Hence it is suggested that theiractivities are mediated by endogenous ethylene, and that theirprimary action leads to increased biosynthesis. (Received November 18, 1974; )  相似文献   
847.
The potential of using nitrate as a terminal electron acceptor to stimulate anaerobic degradation of mixtures of monochlorophenols (MCPs) or dichlorophenols (DCPs) was evaluated. Contaminated and non-contaminated soils were added to water saturated anaerobic microcosms supplemented with 1 mM or 5 mM nitrate. Denitrification and dechlorination activity were present in three diverse soil types and were maintained upon refeeding both nitrate and the appropriate chlorophenol. However, dechlorination activity could only be serially transferred in enrichments with an added electron donor such as acetate. Dehalogenation activity in enrichments from four of the primary microcosms showed at least five different dechlorination reactions, each mediated by different microbial communities. Three of these are distinct ortho-dechlorinating paths; two are meta-dechlorinating and one is the para-dechlorination of 3,4-DCP. Simultaneous dechlorination and denitrification was observed and both activities could be maintained in microcosms but only in the presence of low nitrate concentrations. Dechlorination and denitrification were mediated by two separate microbial communities; one that dechlorinates without use of nitrate and one that denitrifies while oxidizing the dechlorinated aromatic ring. There was no evidence that dechlorination is mediated by the denitrifying community, however the maintenance of a denitrification potential using low (< 1 mM) nitrate concentrations may be useful for completing the food chain by stimulating the mineralization of phenol and benzoate.  相似文献   
848.
The biolistic process   总被引:5,自引:0,他引:5  
The biolistic process is a new process which employs high velocity microprojectiles to deliver substances into cells and tissues. It has been described in different ways and has been referred to as the particle gun method, the microprojectile method, the gene gun method, the particle acceleration method, the bio-blaster method. The inventors of the process have coined the term ‘biolistic’ (biological ballistics) to describe both the process and any associated apparatus used to shoot biological materials into living targets.  相似文献   
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