Characteristics of inapparent Aleutian disease virus infection in mink.     

S H An  F J DePauli  P Wright  D G Ingram 《Research in veterinary science》1978,24(2):200-204

Inapparent of nonprogressive Aleutian disease virus (ADV) infection is a subclinical but persistent virus infection of mink. Mink with the inapparent type of ADV infection when subjected to stress did not develop the progessive form of the disease. However, when challenged with a large dose of the virus, these mink did develop progressive Aleutian disease indicating that they were not highly resistant to the virus. Sera of mink with either the progressive of the inapparent type of ADV infection did not neutralise the virus. The anti-ADV antibody activity in mink with inapparent type of ADV infection was in the IgG fraction of the serum the same as in mink with progressive Aleutian disease. These data indicate that the resistance of the mink with inapparent infection as compared to mink with progressive Aleutian disease was not due to a difference in the class of immunoglobulin response to the virus. However, mink with progressive Aleutian disease showed a greatly increased immunoglobulin response.  相似文献   

Scanning electron microscope study of Sendai virus fusion between HeLa cells and chick erythrocytes.     

A D Irvin  H S Anger  E R Young  J F Reeves 《Research in veterinary science》1978,25(1):67-75

Chick erythrocytes were fused with HeLa cells by Sendai virus and preparations examined by scanning electron microscopy at different times after fusion. Heterokaryons were usually formed by fusion of erythrocyte ghosts with HeLa cells. Occasionally whole erythrocytes were engulfed but there was no evidence that free nuclei fused. Initial inter-cell attachments were usually, and possibly always, made at the site of an attached virus particle. This study helps to correlate topographical findings with previous two-dimensional studies with the transmission electron microscope and may also provide a model system for the fusion of parasitised erythrocytes with eukaryotic cells.  相似文献   

The redox potential of growing cultures of Streptococcus bovis Orla-Jensen compared with other facultative anaerobes.     

J Wolstrup  S A Chaudry  V Jensen 《Acta veterinaria Scandinavica》1978,19(4):535-542

The changes of redox potential were measured in growing cultures of three strains of Streptococcus bovis, together with three strains of Staphylococcus aureus and one strain of each of Lactobacillus plantaram, Lactobacillus casei, and Eschericia coli. It was found that both S. aureus and E. coli could reduce the redox potential of the growth medium to very low values (between —400 mv and —600 mv), whereas the streptococci and lactobacilli were able to cause only slight or insignificant changes of the redox potential. Respirometric measurements confirmed that the capacity of oxygen consumption of S. bovis was very small compared to that of E. coli and S. aureus. On this basis the authors conclude that S. bovis in all probability is unable to contribute significantly to maintenance of the low redox potential of its natural habitat, the rumen. This function must be carried out by other bacteria, such as enterobacteria or staphylococci, which are capable of performing a true, aerobic respiration.  相似文献   

Miniaturized methods for testing the toxicity of pesticides to microorganisms     

S. L. COOPER  G. I. WINGFIELD  R. La WLEY  M. P GREAVES 《Weed Research》1978,18(2):105-107

A minialurized method of determining the toxicity of pesticides to large numbers or soil mitroorganisms is described. Bacteria. actinomycetes, yeasts, fungi and algae can be used as test organisms. A modification of the method allows determination of minimum inhibitory concentrations of pesticides to specific microorganisms. Some results obtained with herbicides are presented. Microméthodex pour éprauver la toxicité des pesticides vis-á-vis des micro-organismes Une micromethode pour determiner la toxicité des pesticides vis-á-vis de nombreux micro-organismes du sol est décrite. Des bactéries. des actinomycetes, des levures. des champignons et des algues peuvent ëtre utilisés comme organismes-tesis. Une modifitation de la méthode permel les determinations des concentrations minimales inhibitrices des pesticides vis-á-vis des micro-organismes specifiques. Quelques resultats obtenus avec des herbicides sont présentés. Miniaturisierte Methoden zur Prüf'ung der Toxizitüt von Pflan- zenhehandlumgsmit teln auf Mikraorganismen Es wird einc miniaturisierte Methode zur BestimmungderToxi- zität von Pfianzenbehandlungsmitteln für groβe Zablen von Bodenmikroorganismen beschrieben, Als Testorganismen können Bakterien. Actinomyceten. Hefen, Pilze und Algen benutzi werden. Eine Modifizierung der Methode gestattet die Bestimmung der Minimum-Hemmkonzentration von Pflanzen- behandlungsmitteln auf spezielle Mikroorganismen. Einige Ergebnisse, die mit Herbiziden erarbeitel wurden. sind darge-stellt.  相似文献   

Chlorinated insecticide and PCB residues in fish and mussels of east coastal waters of the middle and north Adriatic Sea, 1974--75.     

M Picer  N Picer  M Ahel 《Pesticides monitoring journal》1978,12(3):102-112

Concentrations of chlorinated pesticides and polychlorinated biphenyls (PCBs) were determined in mussels (Mytilus galloprovincialis) and goby fish (Gibius sp.) collected in four areas located in eastern coastal waters of the middle and north Adriatic Sea. Most samples were collected in early spring and late summer of 1974 and 1975. The compounds p,p'-DDT, p,p'-DDE, p,p'-TDE, and PCBs were detected most frequently. In about 60 percent of the samples dieldrin was also detected. Average wet-weight concentrations of sigmaDDT and PCBs in mussels from the four areas sampled were: Istrian coast, 65 and 76 ppb; Rijeka Bay, 58 and 75 ppb; Zadar, 36 and 128 ppb; Losinj Island, 167 and 133 ppb. Average concentrations in fish samples were: Istrian coast, 124 and 144 ppb; Rijeka Bay, 37 and 82 ppb; Losinj Island, 166 and 157 ppb. Dieldrin concentrations were in the low ppb range. Although major Italian rivers discharge chlorinated hydrocarbons into the north Adriatic, sampling of biota from Istrian coastal waters indicates no significant effect on the pollution level. However, waste waters from small coastal settlements evidently do contribute significantly to chlorinated hydrocarbon contamination of that ocean. Marine samples from Losinj Island had high chlorinated hydrocarbon concentrations, indicating uptake of pollutants from the north Adriatic.  相似文献   

A New Biotype of Red Spider Mite (Tetranychus urticae (Koch)) causing Atypical Damage to Tomatoes.     

G. N. Foster  J. Barker 《Plant pathology》1978,27(1):47-48

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Preliminary observations on the occurrence of the equine XO syndrome.     

A N Bruère  M G Blue  P M Jaine  K S Walker  L M Henderson  H M Chapman 《New Zealand veterinary journal》1978,26(6):145-146

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An Evaluation of the USDA Preshipment Clearance Program for Propagative Material1)     

N.G. SANTACROCE 《EPPO Bulletin》1978,8(1):67-72

One of the programs utilized by PPQ-APHIS-USDA2) to prevent the introduction of hazardous pests and pathogens is known as preclearance. Preclearance relies more on inspection at origin than it does on inspection upon arrival or entry into the United States. Two such programs have been developed by PPQ for plant materials. One, established in 1951, is for bulbs, while the other, established in 1975, is for a few ornamental crops. The USDA, in co-operation with the Plant Protection Services of the Netherlands, Belgium, France, Italy, Fed. Rep. of Germany, Israel and South Africa, has been performing preclearance for bulbous plant propagative materials. Flower bulbs are being precleared in all of the above countries at the request of the exporter's groups of the respective countries. The objective of this clearance is to facilitate the entry of this material, reduce the chances of introducing plant pests and diseases into the United States, and save APHIS manpower at US ports of entry. This is achieved by having USDA personnel working cooperatively with foreign plant protection services in the inspection of material in the field and packing houses in the country of origin. Detection and elimination of plant pests and diseases is a co-operative effort for mutual benefit of both parties.  相似文献   

Herbicidal interference with the photochemical activities of chloroplasts (in vivo and in vitro) of certain crop and weed species     

M. Santakumari  V.S.R. Das 《Pesticide biochemistry and physiology》1978,9(1):119-129

The independent modes of action of diuron and atrazine on the photochemical activities of chloroplasts (In vivo and in vitro) from the leaves of crop plants Pisum sativum and Pennisetum typhoides and the weeds Amaranthus viridis and Cyperus rotundus were investigated. Hill reaction activity (DCPIP photoreduction) of in vivo chloroplasts (chloroplasts isolated from herbicide-sprayed plants) was unaffected by treatment at sublethal or intermediate levels of diuron or atrazine while that of in vitro chloroplasts (chloroplasts incubated in the required herbicidal concentration) was severely inhibited. The ferricyanide catalyzed noncyclic photophosphorylation was markedly reduced in both the in vivo and in vitro chloroplast systems. N-Methyl phenozonium sulfate (PMS)-mediated cyclic photophosphorylation was inhibited in the in vivo system while a pronounced enhancement of activity was noticed in the in vitro chloroplasts. The rate of NADP⁺ photoreduction was severely inhibited in the in vitro chloroplasts. The unaffected in the in vivo system. The herbicidal effects on the photoreactions of isolated chloroplasts were compared with chloroplasts isolated from herbicide-sprayed plants.  相似文献   

Movement and metabolic fate of [14C]ethephon in flue-cured tobacco     

S.C. Domir  C.L. Foy 《Pesticide biochemistry and physiology》1978,9(1):9-22

The absorption, distribution, and metabolic fate of [¹⁴C]ethephon in flue-cured tobacco (Nicotiana tabacum L.) was studied using autoradiography, thin-layer chromatography, high-voltage paper electrophoresis, and liquid scintillation spectrometry. Labeled ethephon penetrated mature leaf tissue easily and was translocated primarily in an acropetal direction. No ¹⁴C activity was detected in any other plant part except the treated leaf. The first day after treatment, most of the translocated ¹⁴C was detected in the midrib, and after 2 days radioactivity was noticed in veinal areas distal to the point of application. Four days later, however, ¹⁴C was detected in slight amounts only in the midrib, indicating that [¹⁴C]ethephon was rapidly degraded by the leaf tissue. Depending on leaf position on the stalk, as much as 92% of the radioactivity had disappeared from the leaf tissue during the first day after treatment, and as little as 5% of the applied radioactivity was recovered 4 days later. Methanol-extracted plant residues contained insignificant amounts of ¹⁴C. All of the ¹⁴C in methanol extracts was present in the form of a labeled compound with an R_f value corresponding to that of ethephon, indicating the absence of any detectable metabolites of the parent compound. Smoke analysis of cigarettes showed that more [¹⁴C]ethylene than ¹⁴CO₂ was recovered in the main stream, whereas the trend was reversed in the case of side stream smoke.  相似文献