Characterization and activation requirements of bovine lymphocytes acquiring cytotoxic activity after interleukin-2 treatment.

Interleukin-2 (IL-2) treatment of cells and generation of non-major histocompatibility complex (MHC)-restricted cytotoxic cells from peripheral blood mononuclear leukocytes (PBML) was studied. Effector-target conjugate assays demonstrated that bovine PBML bound but did not lyse K562, HL60S and HL60R cells unless activated with IL-2. The magnitude of IL-2-activated killing of tumor cells as well as the magnitude of antibody-dependent cellular cytotoxicity depended on the IL-2 concentration. A short treatment (12-18 h) of effector cells with IL-2 was sufficient for development of cytotoxic activity. Withdrawal of IL-2 from the culture resulted in a reduction of cytotoxic activity that could be restored by further addition of IL-2. Cytotoxic activity of IL-2-activated populations obtained after nylon wool or Sephadex G-10 passage, and Percoll gradient centrifugation of PBML suggests that lymphokine-activated killer (LAK) cell activity in PBML is mainly mediated by a non-adherent lymphocyte lacking markers for B-cells. Positive and negative selection experiments using cell sorting confirmed these findings and demonstrated that the cell responsible for LAK cell activity in cattle belongs to a non-monocyte, non-B, CD2+ lymphocyte population. Furthermore, cytotoxic activity could not be generated in CD2+ populations enriched for cells expressing molecules equivalent to human and murine CD4 and CD8. These findings suggest that effector cells mediating non MHC-restricted cytotoxicity in cattle prevail in a population bearing a CD2+, CD4-, CD8- phenotype and that this population depends on the continuous presence of IL-2 for optimal cytotoxic function.     

A paravaccinia virus isolated from cattle.

Isolation of viruses from calves with acute respiratory tract disease were attempted on bovine embryonic lung cell cultures. An isolate obtained from one calf with oral lesions and respiratory disease, designated 44-M-E482, was characterized as a paravaccinia virus on the basis of biological and physical properties. The calf from which the paravaccinia virus 44-M-E482 was isolated did not possess serum neutralizing antibody in its convalescent sera; neither did experimentally inoculated calves possess serum neutralizing antibody to the isolate. However, a low titer of serum neutralizing antibody was produced in one calf after several intravenous injections of the virus. Inoculation of calves with 44-M-E482 into the oral mucosa, skin, nasal cavity and pharynx did not cause any noticeable illness or lesions. The relation of 44-M-E482 to the viruses which cause bovine papular stomatitis and pseudocowpox is discussed.     

Lung-tissue extract as an alternative to serum for surveillance for brucellosis in chamois

Serological surveys are the most-used way to study diseases in free-ranging wild animals. However, the difficulty in obtaining a sufficient number of suitable serum samples is a major problem. To resolve this problem, we investigated the possibility of using lung-tissue extract in place of blood serum for searching for antibodies against Brucella abortus. Antibodies titres against B. abortus was tested from blood serum and lung-tissue extract from 112 chamois and 99 cattle. Although in complement-fixation-test, lung-tissue extract titres usually were one-to three-fold lower than serum titres, there was a good agreement between serum and lung-tissue extract positivity both in chamois and in cattle. The lung-tissue extract appears a suitable resource in monitoring brucellosis in chamois.     

The status of warning services for plant pests in Italy*

A survey of the present status of warning services for plant protection in Italy shows the lack of a national project, so that the different regional governments approach the question in different ways. In spite of this, some common characters are present: (1) most of the regions manage the warning service directly; (2) everywhere, the warning service interacts with research institutes, farmers’ associations, agrometeorological networks and other warning services; (3)‘indirect warning’ is the prevalent model of organization; geographical areas are divided into homogeneous subareas, where information useful for producing advice is collected and elaborated; warnings are then disseminated by different means of communication, and farmers comply with them autonomously; (4) warnings are usually prepared by a team of advisers, who meet periodically, analyse available information and elaborate suggestions for crop protection; (5) available information comes from field monitoring, weather stations, insect and spore traps, forecasting models for pests and diseases; unfortunately, forecasting models are not widespread; (6) the content of warnings is rather uniform, including information on crops, pests and diseases, suggestions for control strategies and, frequently, meteorological conditions and forecasts; (7) different means are used to disseminate warnings to farmers; usually several methods co‐exist: bulletins published in local newspapers, sent by mail or fax, displayed on notice boards or available via the Internet; placards; telephone messages; surveys on local TV or radio.     

Genetic and Pathogenic Diversity of Pseudomonas avellanae Strains Isolated from Corylus avellana Trees in North-west of Italy, and Comparison with Strains from Other Regions

Forty strains of Pseudomonas avellanae isolated from hazelnut (Corylus avellana L.) trees in the Langhe district of Italy were compared with 15 strains collected from various geographic areas. All strains were assessed by rep-PCR genomic fingerprinting using ERIC, REP and BOX primer sets. Cluster analysis was performed by means of UPGMA. To check the possible differential virulence of the strains, pathogenicity tests were carried out by inoculating leaf scars of hazelnut trees in early autumn. Cluster analysis indicated that, during a four-year study, at least five groups of strains were isolated from different hazelnut orchards located in the small district of Langhe. Two groups were isolated from the same twig. Such strains showed around 20% similarity with other P. avellanae strains collected from northern Greece and central Italy. The strains from Langhe were less aggressive to hazelnut than strains from northern Greece and central Italy. These results and previous genomic characterizations indicate a possible correlation between genomic profile type and regional geographic distribution of P. avellanae strains. In addition, the genetic variability found in the strains from Langhe indicates that such populations are older than the more homogenous P. avellanae populations from other regions.     

Influence of Environmental Conditions on Infection of Peach Shoots by Taphrina deformans

ABSTRACT The effect of weather conditions on the infection of peach shoots by Taphrina deformans was investigated both under orchard conditions and in controlled-environment experiments. Leaf curl incidence and severity were related to rainfall, length of wet periods, and temperature during wetness and during the incubation period, as well as to the development stage of shoots. Surface wetness was more important than rainfall for infection to occur. Minimum rainfall for infection was 3 mm, with a wet period of at least 12.5 h; higher amounts of rainfall did not cause infection when the wet period they triggered was shorter. Wet periods initiated by dew or fog were too short for infection to occur. Infection occurred only when air temperature was <16 degrees C during the wet period and <19 degrees C during incubation. Logistic equations relating relative disease incidence and either duration of wetness or temperature were developed under controlled-environment conditions, with asymptotes at >/=48 h of wetness and 相似文献   

COMPUTED TOMOGRAPHIC CHARACTERISTICS OF EOSINOPHILIC PULMONARY GRANULOMATOSIS IN FIVE DOGS

Canine pulmonary eosinophilic granulomatosis is a rare inflammatory pulmonary disease characterized by formation of eosinophilic granulomas that tend to obliterate the normal pulmonary architecture. The purpose of this retrospective study was to describe the CT characteristics of confirmed idiopathic pulmonary eosinophilic granulomatosis in a group of dogs. Five dogs met inclusion criteria. All patients were young adult dogs of variable breeds. No dog had concurrent occult heartworm disease. Computed tomographic characteristics most commonly included pulmonary masses and nodules of variable size, and lesions were most commonly located in the caudal lung lobes. Four dogs had large pulmonary masses with or without additional nodules and one dog had nodular lesions disseminated throughout the entire lung parenchyma. All large eosinophilic granulomas were smoothly margined, heterogeneous pulmonary masses displaying heterogeneous contrast enhancement. A honeycomb‐like enhancement pattern was observed in all but one mass and consisted of multiple hyperattenuating rims delineating central hypoattenuating areas, suggestive of bronchiectatic lung with peripheral enhancing airway walls and fluid‐filled, necrotic bronchial lumen. One dog had evidence of tracheobronchial lymphadenopathy. Findings indicated that canine eosinophilic pulmonary granulomatosis should be included as a differential diagnosis for dogs with CT characteristics of multiple pulmonary masses and/or nodules in caudal lung lobes, and a honeycomb‐like enhancement pattern in masses after intravenous administration of iodinated contrast medium.