Epizootiologic survey for Babesia microti among small wild mammals in northeastern Eurasia and a geographic diversity in the beta-tubulin gene sequences

We previously reported that small wild rodents in Japan harbor two types of novel Babesia microti-like parasites (designated as Hobetsu and Kobe types), but not the type commonly found in the northeastern United States (U.S. type) where human babesiosis is endemic. To determine whether these new types of parasites are distributed in places surrounding Japan, an epizootiologic survey was undertaken in three geographically distant areas in northeastern Eurasia; South Korea, Vladivostok in Russia, and Xinjiang in China. Blood samples were collected from a total of 387 animals comprising 24 species. DNAs extracted from the samples were tested by nested PCR targeting babesial nuclear small-subunit rRNA gene (rDNA), which revealed that small rodents harboring B. microti exist in all three survey areas. Sequence analysis showed that all PCR-positive samples had rDNA sequences virtually identical to that of U.S.-type B. microti. However, when beta-tubulin gene sequences were compared, evident geographic variations were seen. By use of primers specific for each of the beta-tubulin genes of Kobe-, Hobetsu-, and U.S.-type parasites, a type-specific PCR was developed. Parasite with Hobetsu- or Kobe-type sequence was not detected from any of the three survey areas. These findings suggest that U.S.-type B. microti is widely distributed among small wild mammals in temperate zones of not only North America, but also Eurasia, whereas that Hobetsu- and Kobe-type parasites may be uniquely distributed in Japan.     

Eastern equine encephalitis in a flock of emus (Dromaius novaehollandiae).

Eastern equine encephalitis (EEE) was diagnosed in a flock of emus in southeastern Louisiana. The outbreak involved juvenile and adult breeders ranging in age from 20 to 36 months, with an attack rate of 76% and a case fatality rate of 87%. The diagnosis was confirmed by isolation and characterization of the viral agent, and by detection of EEE antibody in two recovered emus. High mortality was preceded by marked depression, hemorrhagic diarrhea, and emesis of blood-stained ingesta. On postmortem examination, hemorrhagic enteritis and multiple petechia of viscera were observed. Microscopic changes included severe necrosis of hepatocytes, intestinal mucosa, and necrotizing vasculitis of the spleen and lamina propria of the intestine. No nervous system lesions were observed. This outbreak occurred concurrently with EEE in horses and was attributed to unseasonably heavy rainfall with an abundance of arthropod vectors and proximity to free-living reservoir host species.     

Ultrasonic measurement of fetal parameters for estimation of gestational age in Korean black goats

The objective of this study was to determine relationship of gestational age with measurement of diameter of head, orbit, trunk, long and short axis of heart, aorta, placentome, umbilical cord and umbilical vein in Korean black goats. In this study, ten pregnant Korean black goats (Capra hircus aegagrus) were used. Pregnancy diagnosis was performed with a 5 MHz linear transducer and ultrasonographic scan were performed at 60, 75, 90, 105, 120 and 135 days after mating with a 4-9 MHz convex transducer. For accurate measurement, all fetal organs were measured at least 3 times. The diameter of head, orbit, trunk, long and short axis of heart, aorta, placentome, umbilical cord and umbilical vein were significantly increased with the gestational age (p<0.05). Of these parameters, trunk (r=0.8876; p<0.001), long axis of heart (r=0.9168; p<0.001) and short axis of heart (r=0.8819; p<0.001) proved to be the more effective measurements than other parameters, as it correlated well with gestational age. Results indicate that ultrasonic measurements of these parameters were useful methods to estimate gestational age in Korean black goat.     

Perianal malignant melanoma in a dog

Melanocytic tumors are relatively common in dogs and most often occur in the oral cavity, lip, skin, digit, and eye. There are notable differences in the behavior of these tumors, depending on their anatomical location. The majority of oral melanomas and two-thirds of melanomas arising from the digit are malignant, whereas most of melanomas originating from the haired skin are benign. The anus and perianal areas are very uncommon sites for melanocytic tumors in domestic animals except horses, and most of those tumors in horses are malignant. To our knowledge, perianal malignant melanoma has not been reported in the dog and its prognosis is unknown.     

Enzyme-linked immunosorbent assay for screening the plasma residues of tetracycline antibiotics in pigs.

The recommended therapeutic doses of three kinds of tetracyclines, oxytetracycline (OTC, withdrawal period, 10 days), chlortetracycline (CTC, withdrawal period, 5 days) and tetracycline (TC, withdrawal period, 5 days), were each administered to a group of 15 pigs. Blood was sampled before drug administration and during the withdrawal period. The concentration of tetracyclines in plasma, determined by semi-quantitative ELISA, was compared with that of internal standard (10 ppb as oxytetracycline). The absorbance ratio of internal standard to sample (B/Bs) was employed as an index to determine the tissue residues in pigs. All 45 plasma samples from nontreated pigs showed negative in the residue of any of three tetracycline antibiotics. OTC was detected in plasma of pigs treated until the 8th day, CTC until the 4th day, and TC was detected until the 3rd day of its withdrawal period. The present study showed that the semi-quantitative ELISA easily be adopted in predicting tissue residues for tetracycline antibiotics in live pigs.     

Expression of nitric oxide synthase 2 and cyclooxygenase-2 in swine experimentally infected with Actinobacillus pleuropneumoniae

The expression of inflammatory mediators was examined in pigs experimentally infected with Actinobacillus pleuropneumoniae. The activity of nitric oxide synthase 2 (NOS2) and cyclooxygenase-2 (COX-2) was determined by measuring nitric oxide (NO) and prostaglandin E2 (PGE2) in bronchoalveolar lavage fluid in response to A. pleuropneumoniae in vivo. By in situ hybridization and immunohistochemistry, both NOS2 and COX-2 enzymes were detected in neutrophils and macrophages that had infiltrated into alveolar spaces. The sharp increase in PGE2 concentration preceded the increase in the concentrations of NO. NO levels were highly correlated with PGE2 level (rs=0.7218, P <0.05). The NO levels were positively correlated with lung lesion scores (rs=0.9087, P <0.05) until 24 hours postinoculation (hpi) as were the lung lesion scores and PGE2 levels (rs=0.925, P <0.01). High levels of PGE2 produced by COX-2 are generated in early infection (6 hpi). However, in later stages of infection (12-36 hpi), there is participation of NO and PGE2 accompanied by coinduction of both NOS2 and COX-2.     

Discovery and directed evolution of a glyphosate tolerance gene

The herbicide glyphosate is effectively detoxified by N-acetylation. We screened a collection of microbial isolates and discovered enzymes exhibiting glyphosate N-acetyltransferase (GAT) activity. Kinetic properties of the discovered enzymes were insufficient to confer glyphosate tolerance to transgenic organisms. Eleven iterations of DNA shuffling improved enzyme efficiency by nearly four orders of magnitude from 0.87 mM-1 min-1 to 8320 mM-1 min-1. From the fifth iteration and beyond, GAT enzymes conferred increasing glyphosate tolerance to Escherichia coli, Arabidopsis, tobacco, and maize. Glyphosate acetylation provides an alternative strategy for supporting glyphosate use on crops.