Virulence-associated protein characterisation of Rhodococcus equi isolated from bovine lymph nodes

Rhodococcus equi has a low pathogenicity in cattle, but it occasionally causes lymph node granulomas, which are detected at abattoir post mortem inspection, and must be distinguished from tuberculous granulomas. Lymph node lesions were detected in 6719 cattle, from a total of 3,263,622 cattle examined post mortem in abattoirs, in the Republic of Ireland, during 1997 and 1998. Histological examination was performed on all lesions, principally for the purpose of identifying animals with tuberculosis. A total of 1122 of the lesions were cultured on blood agar and on Stonebrinks and Lowenstein-Jensen medium containing pyruvate, because the histological findings were difficult to interpret or were suggestive of R. equi infection. R. equi was isolated from 264 lesions. Almost all of the R. equi granulomas were confined to a single lymph node, and were present predominantly in the retropharyngeal, bronchial and mediastinal lymph nodes. R. equi granulomas were present in a significantly higher proportion of the lesions detected in steers and heifers compared to cows. The prevalence in the total population of 3.3 million cattle examined post mortem was 0.008%. The 15-17kDa antigens, associated with virulence in this organism, and the 20kDa antigen, associated with intermediate virulence, were not detected in isolates from 146 cattle, analysed by immunoblot assays. A PCR assay to detect the plasmid gene encoding the 15-17kDa antigens was also negative for isolates from these 146 animals. Plasmids were not detected in 30 isolates which were examined.     

Cutaneous pyogranuloma in a cat caused by virulent Rhodococcus equi containing an 87 kb type I plasmid

A 2-year-old intact male domestic shorthaired cat presented with a chronic, nodular, ulcerated, cutaneous lesion on the right thoracic limb. Histological and cytological examination revealed a pyogranulomatous inflammation with basophilic organisms in the macrophages. A virulent form of Rhodococcus equi containing an 87 kb type I (VapA) virulence plasmid was identified from cultures of biopsy samples. This report describes the clinicopathological features, plasmid profile and virulence of this case of R equi infection.     

Experimental infection of laying chickens with egg-drop syndrome 1976 virus

Brown layer hens (BC and HC strains) and white layer hens (WL strain) orally infected with the H-162 strain of the egg-drop syndrome 1976 virus developed few clinical signs except for abnormal egg production. Depressed and/or aberrant-egg production was observed for 3 days or longer in 17 of 18 BC hens, 13 of 15 HC hens, and 10 of 17 WL hens. On the average, abnormal egg production began 8.8, 10.3, and 12.2 days after infection of the BC, HC, and WL hens, respectively. Egg production was depressed in the WL hens, but little depression was observed in the BC and HC hens. Aberrant-egg production was much less frequent in the WL hens than in the BC and HC hens. Aberrant eggs were shell-less, soft-shelled, thin-shelled, and/or discolored. No eggs of abnormal internal quality or shape were observed. The virus spread from infected BC and WL hens to contact hens.     

Effect of continuous compost application on water-stable soil macroaggregation in a field subjected to double cropping

The influence of continuous application of compost and fertilizer on soil macroaggregation in a field subjected to long-term (ca. 20 years) double cropping (rice and barley) was investigated. Soil samples were collected from 4 different plots: a) No-NF, fertilizer containing P and K but no N; b) F, fertilizer containing N, P, and K; c) F+ LC, fertilizer plus low rate of compost; and d) F+ HC, fertilizer plus high rate of compost. The application of compost and fertilizer increased the degree of macroaggregation (>0.25 mm), the contents of organic C, total N, hydrolyzable carbohydrates, and dithionitecitrate-bicarbonate (DCB) soluble Al, and the hyphal length in the order of No-NF<F<F+LC<F+HC plots. The degree of macroaggregation showed high correlation coefficients (r ≥ 0.95) with the contents of organic and inorganic components or the hyphal length. Most of these properties were strongly intercorrelated among themselves. The results obtained in this study suggest that organic matter including polysaccharides, active Al, and hyphae play an important role together in soil macro aggregation in the field subjected to double cropping under study.     

Evaluation of the in vitro growth-inhibitory effect of epoxomicin on Babesia parasites

Epoxomicin potently and irreversibly inhibits the catalytic activity of proteasomal subunits. Treatment of proliferating cells with epoxomicin results in cell death through accumulation of ubiquinated proteins. Thus, epoxomicin has been proposed as a potential anti-cancer drug. In the present study, the inhibitory effects of epoxomicin on the in vitro growth of bovine and equine Babesia parasites were evaluated. The inhibitory effect of epoxomicin on the in vivo growth of Babesia microti was also assessed. The in vitro growth of five Babesia species that were tested was significantly inhibited (P < 0.05) by nanomolar concentrations of epoxomicin (IC₅₀ values = 21.4 ± 0.2, 4 ± 0.1, 39.5 ± 0.1, 9.7 ± 0.3, and 21.1 ± 0.1 nM for Babesia bovis, Babesia bigemina, Babesia ovata, Babesia caballi, and Babesia equi, respectively). Epoxomicin IC₅₀ values for Babesia parasites were low when compared with diminazene aceturate and tetracycline hydrochloride. Combinations of epoxomicin with diminazene aceturate synergistically potentiated its inhibitory effects in vitro on B. bovis, B. bigemina, and B. caballi. In B. microti-infected mice, epoxomicin caused significant (P < 0.05) inhibition of the growth of B. microti at the non-toxic doses of 0.05 and 0.5 mg/kg BW relative to control groups. Therefore, epoxomicin might be used for treatment of babesiosis.     

Response biomarkers of inhalation exposure to cigarette smoke in the mouse lung

Cigarette smoking is known to increase the risk of cancer and chronic obstructive pulmonary disease (COPD). In this study, we evaluated the effects of short-term nose-only inhalation exposure to cigarette smoke in mice. Male 10-week-old C57BL mice were exposed to clean air (control) or mainstream cigarette smoke for 1 h/day, 5 days/week, for 2 or 4 weeks. Exposure to cigarette smoke increased the number of inflammatory cells, especially neutrophils, in the bronchoalveolar lavage fluid, increased inflammatory cell infiltration foci, and caused an increase in the thickness of the peripheral bronchial epithelium. Microarray gene expression analysis indicated that smoke exposure induced inflammatory responses, including leukocyte migration and activation of phagocytes and myeloid cells, as early as two weeks after the initiation of exposure. Importantly, chemokine (C-C motif) ligand 17, resistin-like alpha, and lipocalin 2 were upregulated and may serve as useful markers of the toxic effects of exposure to cigarette smoke before pulmonary histological changes become evident.     

Bovine spongiform encephalopathy (BSE) safety measures in Japan

Since the first identification of bovine spongiform encephalopathy (BSE) in Japan in September 2001, a series of safety measures was introduced by the Ministry of Agriculture, Forestry and Fisheries, the Ministry of Health, Labour and Welfare and the Food Safety Commission of the Cabinet Office. These measures included blanket BSE testing and removal of specified risk materials at slaughterhouses, surveillance of risk animals and a ban on the use of meat-and-bone meals and traceability on all farms. The Japanese experience over the past five years has shed light on several issues in countries that have a low BSE incidence.     

Potassium acetate-catalyzed acetylation of wood at low temperatures I: simplified method using a mixed reagent

Ezomatsu wood blocks were acetylated in a mixture of acetic anhydride and acetic acid containing excess potassium acetate (KAc). The mixture method enabled rapid acetylation at 120°C: a 20% weight gain (weight percent gain; WPG) was achieved within 30 min while the WPG did not exceed 18% after 120 min of conventional uncatalyzed acetylation. At 40°C, however, a satisfactory WPG was not achieved with the mixture method because both the wood swelling and KAc concentration in the reagent solution were limited at that temperature. In addition, the antiswelling efficiency attained by the mixture method was irregularly low, probably because of nonuniform reaction involving shrinkage of the cell lumina. These results suggest that the mixture method is not advantageous for low-temperature acetylation, whereas it enables simple and rapid acetylation at high temperature.