Molecular epidemiology of virulent Rhodococcus equi from foals in Brazil: virulence plasmids of 85-kb type I, 87-kb type I, and a new variant, 87-kb type III

We investigated the prevalence of virulent Rhodococcus equi in clinical isolates from 41 foals (19 sporadic and seven endemic cases) in Brazil between 1991 and 2003. Of the 41 virulent isolates, six contained an 85-kb type I plasmid, 33 contained an 87-kb type I plasmid, both of which have been found in isolates from the Americas, and the remaining two contained a new variant, which did not display the EcoRI, EcoT22I and BamHI digestion patterns of the 11 representative plasmids already reported (85-kb types I-IV; 87-kb types I and II; 90-kb types I-V). We tentatively designated the new variant as the '87-kb type III' plasmid, because its BamHI digestion pattern is similar to that of the 87-kb type I plasmid. This is the first report of the molecular epidemiology surveillance of virulent R. equi in clinical isolates from Brazilian foals.     

Insulin-like growth factor-I as a follicular growth promoter during early pregnancy in thoroughbred mares

To elucidate the physiological role of insulin-like growth factor-I (IGF-I) during early pregnancy in mares, number of ovarian follicles was monitored ultrasonically during different stages of the first trimester of pregnancy in 36 thoroughbred mares. From 9 of 36 mares, blood samples were collected weekly from the mating day till the end of the first trimester of pregnancy and plasma IGF-I profiles were examined with other hormones, like follicle stimulating hormone (FSH), luteinizing hormone (LH), ir-inhibin, progesterone and estradiol-17beta. Plasma IGF-I level fluctuated throughout the studied period with four peaks on the 7th, 28th, 49th and 84th days of pregnancy. Plasma IGF-I showed a positive correlation with plasma FSH (P<0.05), whereas no correlation was found with other hormones during the studied period. Plasma IGF-I had no correlation with the foetal size, but positive correlation with the number of large (> 30 mm) and medium (10-30 mm) follicles. These results suggested that IGF-I might produce from the medium and large follicles during early pregnancy and promote to develop their growth via pituitary FSH mediated effects in the mares.     

Foliar spray of validamycin a or validoxylamine a controls tomato fusarium wilt

ABSTRACT Tomato wilt, caused by the soilborne fungus Fusarium oxysporum f. sp. lycopersici, is effectively controlled by a foliar spray of validamycin A (VMA) or validoxylamine A (VAA) (>/=10 mug/ml); however, neither VMA nor VAA is antifungal in vitro. In pot tests, the effect of a foliar application of VMA or VAA at 100 mug/ml lasted for 64 days. Plants sprayed with VMA or VAA accumulated salicylic acid and had elevated expression of the systemic acquired resistance (SAR) marker genes P4 (PR-1), Tag (PR-2), and NP24 (PR-5). Foliar spray of VMA also controlled late blight and powdery mildew of tomato. The disease control by VMA and VAA lasted up to 64 days after treatment, was broad spectrum, and induced the expression of PR genes, all essential indicators of SAR, suggesting that VMA and VAA are plant activators. The foliar application of plant activators is a novel control method for soilborne diseases and may provide an economically feasible alternative to soil fumigants such as methyl bromide.     

Mechanism of resistance to carpropamid in Magnaporthe grisea

The inhibitory activity of carpropamid on scytalone dehydratase (SDH) extracted from a carpropamid-resistant strain of Magnaporthe grisea (Hebert) Barr was dramatically reduced in comparison with that on SDH extracted from the sensitive strain. A single-point mutation (G to A) located at the upstream region (233 bp downstream from the ATG codon) resulting in a one-amino-acid substitution (valine [GTG] 75 to methionine [ATG]: V75M) was found in the resistant strain. To examine whether the V75M mutation is the primary reason for decreasing the sensitivity of SDH to carpropamid, the SDH cDNAs of both the sensitive and the resistant strain were cloned into a GST-fused protein expression vector-system. The recombinant SDHs of both strains exhibited the same sensitivities to carpropamid as those extracted from the mycelia of the respective strains. These data clearly revealed that the V75M mutation causes the low sensitivities of the SDHs of the carpropamid-resistant strains, and strongly suggests that the V75M mutation confers resistance of these strains to carpropamid.     

Isolation of Rhodococcus equi from the feces of indigenous animals and soil from the Lower Zambezi National Park and Lochinvar National Park, Zambia

Rhodococcus equi is an important pathogen in foals; however, its incidence in African indigenous animals is poorly understood. Fecal samples (92 from nine indigenous species) and 43 soil samples were collected from two Zambian National Parks. The presence of R. equi was investigated and 533 isolates were tested for the presence of 15- to 17-kDa antigens (VapA) and a 20-kDa antigen (VapB) by immunoblotting and PCR. R. equi was isolated (10(2)-10(4) colony forming units/g) from 75% of fecal and 74% of soil samples. Neither antigen was detected; however, about 20% of the isolates contained cryptic plasmids of various sizes. There was no evidence of virulent R. equi, but the avirulent form was widespread in the animals and the soil.     

Bulk cultures of canine peripheral blood lymphocytes with solid phase anti-CD3 antibody and recombinant interleukin-2 for use in immunotherapy

Interleukin (IL)-2 can induce large numbers of lymphokine-activated killer cells in peripheral blood lymphocytes (PBL), but IL-2 alone cannot induce proliferation of a large number of canine (c) PBL. We used the solid phase anti-CD3 antibody and soluble recombinant (r) IL-2 in order to establish a large scale culture method for cPBL. The number of lymphocytes seeded (3 x 10 (7)) increased to 1 x 10(9) after incubation for 10 days. The phenotype of cultured cPBL cells (after 2 weeks) showed a CD4(+) or CD8(+) predominant cell population. The cultured cell solutions were administered with physiological saline intravenously to each dog. After transfusion of the cultured cells, the cPBL counts, especially the number of CD4(+), CD8(+) and CD4(-)CD8 (-)(DN) cells increased significantly in the recipient dogs. Natural killer (NK) cells, gammadeltaT cells and B cells were considered to be present in the DN cell population. The NK cells and gammadeltaT cells showed no adverse reaction to the transfusion of the activated cPBL. Therefore, it is necessary to recognize the B cells present in the DN cell population by detecting CD21(+) cells. In conclusion, the bulk culture system of cPBL with rIL-2 and solid phase anti-CD3 antibody may be useful for the development of novel immunotherapy in dogs.     

Morphological adaptation of the skull for various behaviors in the tree shrews

Skull size and shape were examined among 14 species of the tree shrews (Tupaia montana, T. picta, T. splendidula, T. mulleri, T. longipes, T. glis, T. javanica, T. minor, T. gracilis, T. dorsalis, T. tana, Dendrogale melanura, D. murina, and Ptilocercus lowii). The bones of face were rostro-caudally longer in T. tana and T. dorsalis, contrasting with T. minor and T. gracilis, D. melanura, D. murina and P. lowii which have smaller facial length ratios. The arbo-terrestrial species (T. longipes and T. glis) were similar to terrestrial species in length ratios of bones of face unlike the other arbo-terrestrial species (T. montana, T. picta, T. splendidula, and T. mulleri). We propose that T. longipes and T. glis have adapted to foraging for termites and ants as have T. tana and T. dorsalis. Additionally small body size in T. javanica may be the result of being isolated in Java. We separated the species into 5 groups from the measurment values of skulls: 1) Terrestrial species; T. tana and T. dorsalis, 2) Arboreal species; T. minor and T. gracilis, 3) Arbo-terrestrial species group 1: T. montana, T. splendidula, T. picta and T. mulleri, and T. javanica, 4) Arbo-terrestrial species group 2: T. glis and T. longipes, 5) Arboreal species of Dendrogale and Ptilocercus. Principal component analysis separated species into 8 clusters as follows: 1) T. tana, 2) T. dorsalis, 3) T. montana, T. splendidula, T. picta and T. mulleri, 4) T. glis and T. longipes, 5) T. javanica, 6) T. minor and T. gracilis, 7) D. melanura and D. murina, and 8) P. lowii. We suggest that these clusters correspond to behavioral strategies and peculiarities observed in foraging, feeding and locomotion in each species.     

Hydrocephalus with visual deficits in a cat

A 22-month-old male Japanese mongrel cat with a history of dysuria and recurrent generalised tonic-clonic seizure was examined by neuro-opthalmological testing and computed tomography (CT). Vision testing revealed narrowing of the visual field in the right eye, and complete visual deficits in the left eye. Pupillary reactions, and motor and sensory function in the eyelids and the eyes were normal. The cat was diagnosed as hydrocephalus by CT examination, because dilation of the right lateral ventricle, and compression of the right temporal and occipital cortices was shown. The etiology of the hydrocephalus was unclear. Although a unilateral lesion of the upper visual pathway was suspected, a complete homonymous hemianopsia was not shown.     

Immunohistochemical detection of P-glycoprotein (PGP) and multidrug resistance-associated protein (MRP) in canine cutaneous mast cell tumors

Fifty-four canine cutaneous mast cell tumors were evaluated immunohistochemically for the expression of P-glycoprotein (PGP) and multidrug-resistance-associated protein (MRP). All tumors examined were graded according to the histological malignancy. ranging from grade I to III. The expression of PGP was confirmed in 15% (8/54) of whole, 33% (5/15) of grade I, 10% (3/31) of grade II, and 0% (0/8) of grade III tumors. The expression of MRP was found in 18% (10/54) of whole, 26% (4/15) of grade I, 19% (6/31) of grade II, and 0% (0/8) of grade III tumors. The cases positive to at least one of these 2 multidrug markers were 26%, 47%, 23% and 0% of whole and grade I to III tumors, respectively. These results indicate that at least 26% of canine cutaneous mast cell tumors express PGP and/or MRP and that these tumors may be resistant to several anti-cancer drugs.     

Effects of inoculum density, leaf age, moisture, temperature, and wetness duration on black streak of edible burdock

Inoculum density, temperature, leaf age, and wetness duration were evaluated for their effects on the development of black streak (Itersonilia perplexans) on edible burdock (Arctium lappa L.) in a controlled environment. The effect of relative humidity (RH) on ballistospores production by I. perplexans was also evaluated. Symptoms of black streak on leaves increased in a linear fashion as the inoculum density of I. perplexans increased from 10² to 10⁶ ballistospores/ml. Rugose symptoms on young leaves were observed at densities of ≥10⁴ ballistospores/ml. Disease severity of I. perplexans in relation to leaf age followed a degradation curve when the leaves were inoculated with ballistospores. Disease severity was high in newly emerged leaves up to 5 days old, declined as leaf age increased to 29 days, and was zero when leaf age increased from 30 to 33 days. Disease development of edible burdock plants exposed to ballistospores of I. perplexans was evaluated at various combinations of temperature (10°, 15°, 20°, 25°C) and duration of leaf wetness (12, 24, 36, 48, and 72 h). Disease was most severe when plants were in contact with the ballistospore sources at 15° or 20°C. The least amount of disease occurred at 25°C regardless of wetness duration. Ballistospores required 24–36 h of continuous leaf wetness to cause visible symptoms by infection on edible burdock. Ballistospores production in infected lesions required at least 95.5% RH.