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11.
In field experiments, larvae of codling moth Cydia pomonella (L.) rarely acquired granulosis virus on hatching from the egg, but picked up most later, on the tree surface. Deposits of virus sprayed in 1.0% w/v skimmed milk did not affect neonate larval behaviour. Larvae died, usually in the first instar, after entering treated fruit, but they frequently entered via the calyx or near the base of the stalk or through cracks in the skin, where little feeding damage by first-and sometimes second-instar larvae was seen.
Résumé En verger, la pulvérisation d'oeufs de carpocapse avec du virus de la granulose en suspension dans l'eau (additionnée de lait écrémé dilué à 1%) n'a pas modifié la survie des chenilles avant pénétration dans le fruit; par contre la pulvérisation des arbres a provoqué une forte mortalité. Bien que des chenilles consommant des poils et la surface des feuilles aient été observées avant leur pénétration dans le fruit, ce qui aurait pu provoquer leur contamination par le virus, il semble que la contamination létale provienne des fruits seuls.La présence de produit n'a modifié ni le comportement larvaire, ni le taux de pénétration dans les fruits; la mortalité y a lieu ensuite, généralement au premier stade. Dans 74 à 78% des cas, les chenilles ont pénétré dans le fruit par le calice ou près de la base du pédoncule — aucun dégât provenant de larves du premier stade n'y était visible, de même que dans le calice pour les larves du deuxième stade. Par contre, toute pénétration par la surface du fruit était repérable dès le premier stade. Il est possible que la répartition des lieux de pénétration dans le fruit influe sur la létalité due au virus et explique les variations d'efficacité observées en verger. Un système de classification des dégâts, provoqués lors de la pénétration dans le fruit, de chenilles du premier au troisième stade est proposé pour évaluer l'efficacité des essais en verger.相似文献
12.
Effect of Light on the Metabolism of Lipids in the Rat Retina 总被引:1,自引:1,他引:0
Robert E. Anderson Maureen B. Maude Glen A-Wen Pu Joe G. Hollyfield 《Journal of neurochemistry》1985,44(3):773-778
The effect of light on the in vitro incorporation of a variety of radioactive precursors into glycerolipids was tested in isolated retinas of albino rats. There was an increase in the incorporation of [2-3H]myo-inositol, 32Pi, [2-3H]glycerol, and [methyl-3H]choline into retinal phospholipids in light compared to that in darkness. [2-3H]myo-Inositol was incorporated primarily into phosphatidylinositol. 32Pi was incorporated primarily into the phosphoinositides, although there were significant increases in the specific activities of all retinal phospholipids in light compared to those in darkness. Likewise, [2-3H]glycerol incorporation into all retinal phospholipids and diglycerides was greater in light than in the dark. There was no effect of light on the incorporation of [2-3H]ethanolamine into phosphatidylethanolamine or of [3-3H]serine into phosphatidylserine, although these phospholipids were labeled to a greater extent in light with [2-3H]glycerol. There was no effect of light on the incorporation of [3H]palmitic acid into diglycerides and phospholipids, with the exception of phosphatidylinositol. Light also had no effect on the uptake of [2-3H]glycerol, [2-3H]inositol, or [methyl-3H]choline into the retina. We conclude from these studies that light stimulates the phosphoinositide effect in the rat retina. Although some of the results are consistent with a stimulation of de novo synthesis of all lipid classes, our studies with [3H]palmitate, [2-3H]ethanolamine, and [3-3H]serine do not support this conclusion.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
13.
The objective of this study was to determine the feasibility of using airborne T3 coliphage as a viral tracer in microbial aerosols. Although T3 coliphage was relatively stable when stored either at temperatures ranging from 21 to 37 C or in the frozen state at -20 C, there was a 2-log loss in infectivity when stored for 72 days at 4 C. Either agitation of stored coliphage suspensions held at 31 C or wide fluctuations in storage temperature produced an increased loss of infectivity. In the airborne state, freshly prepared coliphage and stored coliphage behaved similarly, with survival diminishing as the relative humidity (RH) was lowered. The greatest loss occurred during the first five min following aerosolization. The results showed that only under certain conditions of temperature and relative humidity can T3 coliphage be used as a satisfactory aerosol tracer. 相似文献
14.
An analytical model for the counter-current heat exchange mechanism in animals has been formulated and a solution has been obtained. The nondimensional parameters that govern the mechanism have been determined in terms of the properties of the animal. The normalized temperatures are functions of normalized distance and, in general, three nondimensional heat transfer conductances. Graphical results are presented for two representative physiological systems. These results allow a delineation of those situations in which counter-current heat transfer is important, and also a quantitative prediction of the heat transfer and temperature distributions. The theory is compared to the available experimental results. 相似文献
15.
In Vitro Studies on the Antiviral Activity of 1,3-Bis(2-Chloroethyl)-1-Nitrosourea 总被引:1,自引:1,他引:0
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Chemotherapy experiments carried out in vitro demonstrated that 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) was active against lymphocytic choriomeningitis virus and had an equivocal antiviral effect on Semliki Forest, herpes simplex, and vaccinia viruses. No antiviral effect was observed with BCNU against western equine encephalomyelitis, polio, and parainfluenza (HA-1) viruses. Activity of the drug was determined by inhibition of viral-induced cytopathogenic effect in KB or chick embryo cells and by reduction of virus titer in cell culture supernatant fluid. Maximal activity against the viruses was observed when drug and virus were incubated together for 30 min prior to addition to cells; essentially no activity could be demonstrated if BCNU and virus were added to cells with no prior incubation. 相似文献
16.
Summary The triacylglycerol fatty acid and sterol profiles of microorganisms from three McMurdo Sound sediment sites, collected during the austral summer of 1984–1985, were determined using gas chromatography and gas chromatography-mass spectrometry. Comparison of the three sites indicated that Cape Evans contained the greatest concentration of triacylglycerol (TG) (220 nmoles/gram dry weight (gdw) of sediment), approximately six to seven times that determined for sediment microorganisms from the Cape Armitage and New Harbor sites. The relative proportion of triacylglycerolderived polyunsaturated fatty acids (PUFA) revealed a somewhat different trend. New Harbor sediment contained the greatest relative proportion of PUFA (22% of triacylglycerol fatty acids), followed by Cape Evans (16%) and Cape Armitage (11%). The proportion of unsaturated fatty acids (poly-and monounsaturated) was relatively constant and ranged from 63% to 71% of the triacylglycerol fatty acids for the three sites. Sterol concentrations varied from 610 pmoles/gdw at Cape Evans, to 370 and 240 pmoles/gdw for Cape Armitage and New Harbor respectively, and was approximately 1% of the total determined lipid. Cholesterol was the major sterol component detected, occurring at similar relative levels (29%) for all three sites. Other sterols present in decreasing order of abundance were 22-dehydrocholesterol, brassicasterol, 24-ethylcholesterol and 24-methylcholesterol. 5-stanols were only minor components of the three sediments, indicating that in situ biohydrogenation of stenols was not a major sterol transformation process in these recent surface oxic sediments.Part 3 in the series: Microbial Ecology in Antarctic Sea-Ice and Benthic Communities 相似文献
17.
Validation of signature polarlipid fatty acid biomarkers for alkane-utilizing bacteria in soils and subsurface aquifer materials 总被引:3,自引:0,他引:3
David B. Ringelberg John D. Davis Glen A. Smith Susan M. Pfiffner Peter D. Nichols Janet S. Nickels J.Michael Henson John T. Wilson Marylynn Yates Donald H. Kampbell Harvey W. Read Thomas T. Stocksdale David C. White 《FEMS microbiology letters》1989,62(1):39-50
Abstract Extractable cell membrane-derived polarlipid ester-linked fatty acids (PLFA) obtained from aerated soils gassed with methane or propane and from methane- and propane-oxidizing bacteria isolated from the soils were analyzed by capillary gas chromatography/mass spectrometry. Exposure of aerated soils to methane resulted in the formation of a high proportion of an unusual 18-carbon mono-unsaturated PLFA, 18:lw8c. High proportions of this fatty acid biomarker are found in monocultures from this soil grown in minimal media with methane. This PLFA has been previously established as associated with authentic type II methane-oxidizing bacteria. The microbiota in aerated soils exposed to hydrocarbons containing propane, formed a suite of PLFA characterized by high proportions of a 16-carbon mono-unsaturated acid, 16:lw6c, and an 18-carbon saturated fatty acid with an additional methyl branch at the 10 position, 10 Me 18:0. This PLFA pattern has been detected in several monocultures enriched from the soil with propane-amended minimal media. The correspondence of high proportions of these unusual mono-unsaturated PLFA in the isolated monocultures and in situ in the soils after stimulation with the appropriate hydrocarbon is a strong validation of the utility of these biomarkers in defining the community structure of the surface soil microbial community. 相似文献
18.
Lisa M. Vogler Sumner W. Jones Glen E. Jensen R. Gary Brewer Karen J. Brewer 《Inorganica chimica acta》1996,250(1-2):155-162
A number of osmium and ruthenium complexes of the tridentate ligands 2,2′:6′,2″-terpyridine (tpy) and 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tpp) have been prepared and characterized by our laboratory. All these complexes possess metal based oxidations and ligand based reductions localized on each polyazine ligand. Polymetallic complexes bridged by the tpp ligand exhibit two sequential tpp based reductions prior to the reduction of other polyazine ligands in these complexes. The spectroscopy of these complexes is dominated by ligand based π-π* transitions in the ultraviolet and MLCT (metal-to-ligand charge transfer) bands terminating on each polyzine ligand in the visible. For the complexes reported herein the lowest lying optical transitionis a M → BL CT band. For most of the complexes reported, occupation of this excited state gives rise to an observable emission at room temperature. For ruthenium complexes of these tridentate ligands, the presence of a low-lying LF state shortens the excited state lifetimes of these chromophores. This gives rise to ruthenium complexes that display shorter excited state lifetimes than the analogous osmium based systems. Incorporation of tpp based chromophores into polymetallic frameworks leads to the production of bimetallic species with long-lived excited states, 100 ns at room temperature. This makes these chromophores good candidates for the development of stereochemically defined supramolecular complexes. It is possible to measure an electrochemical HOMO-LUMO energy gap and a correlation between this electrochemically measured energy gap and the spectroscopic energy associated with this HOMO→LUMO transition are reported herein (HOMO== highest occupied molecular orbital, LUMO = lowest unoccupied molecular orbital). 相似文献
19.
Hydroperoxide inactivation of enzymes within spores of Bacillus megaterium ATCC19213 总被引:2,自引:0,他引:2
Abstract Hydroperoxide inactivation of the protoplast enzymes enolase, aldolase and glucose-6-phosphate dehydrogenase in intact spores of Bacillus megaterium ATCC19213 was assessed by first treating the cells with lethal levels of H2 O2 , then germinating them in the presence of chloramphenicol prior to permeabilization and enzyme assays. Glucose-6-phosphate dehydrogenase proved to be more sensitive to H2 O2 than enolase or aldolase, in agreement with findings for isolated enzymes. Average D values (time for 90% inactivation) for spores treated with 0.50% H2 O2 were 173 min for enolase, 67 min for aldolase and 32 min for glucose-6-phosphate dehydrogenase, compared with a D value of 34 min for spore killing. H2 O2 killing of spores was found to be conditional in that recoveries of survivors were greater on complex medium than on minimal medium. Overall, it appeared that oxidative inactivation of enzymes may be important for hydroperoxide killing of spores. 相似文献
20.
The behaviour of the endoparasitic tracheal mite, Acarapis woodi (Rennie) on honey bees (Apis mellifera L.) is a challenge to observe because of its small size. Through a microscope, we videotaped this mite's movement on young bees, dead bees and bees exposed to vegetable oil. Previous studies have shown that solid vegetable oil decreases mite infestations in a bee colony. We hypothesized that the oil alters mite behaviour to the detriment of the parasite, thus helping to safeguard the host. Habitat-seeking behaviour, identified as necessary for mites to locate a new host environment, was disrupted on both dead and oil-treated bees. Questing behaviour, which is associated with transfer between hosts, increased significantly on the dead and oily bees. The behaviours of mites were significantly different between all three treatments (x
2=494.96, p<0.001 on dead bees and x
2=851.11, p<0.001 on oily bees). Both questing and seeking behaviours were significantly different on each of the thoracic treatments (F
2,66=7.88, p<0.001 and F
2,66=21.28, p<0.001) and mite questing behaviour was not altered between males and females on live or oily bees (F
1,22=0.25, p<0.62), but habitat seeking was (F
1,22=7.42, p<0.012). The male questing and habitat-seeking behaviours were observed. We conclude that oil-treated bees gained protection from habitat-seeking mites because the normal behaviour of the mites seeking an oviposition site is interrupted. 相似文献