Evaluation of coproantigen diagnosis for natural Echinococcus multilocularis infection in red foxes.

The validity of a coproantigen ELISA for Echinococcus multilocularis was evaluated by comparison of three diagnostic methods; autopsy, egg examination and the ELISA. Of 71 foxes, 39 were found to be infected with the cestode at autopsy. The overall mean of worm burdens was 3,451, but the number varied (1-34,522). The ELISA could detect 94.9% (37/39) of the worm positives and there were no false-positives. Two false-negatives were infected with 1 and 4 cestodes, whereas 3 cases with similar worm burdens (2, 4 and 6 worms) were diagnosed as positives. This indicates the detection limit of the assay may be equivalent to less than 10 (in the worm burden). On the other hand, egg examination showed low sensitivity (43.6%, 17/39). These results suggest the ELISA has a potential to replace for the conventional methods.     

Isolation of Salmonella organisms from the mesenteric lymph nodes of horses at necropsy.

OBJECTIVES: To determine the prevalence of Salmonella infections in horses at necropsy. DESIGN: Cross-sectional prevalence survey. ANIMALS: 102 horses. PROCEDURE: Mesenteric lymph nodes were collected from horses that were necropsied. Horses had died or were euthanatized because of severe disease or at the request of the owner. Twenty-eight of the horses were racehorses euthantized following acute catastrophic injuries on the racetrack. Mesenteric lymph nodes were submitted for Salmonella culture via direct plating of tissue specimens on MacConkey agar and by use of 4 enrichment culture techniques that used tetrathionate and selenite enrichment broth and brilliant green and Salmonella-Shigella selective plating media. RESULTS: Salmonella typhimurium was isolated from the mesenteric lymph nodes of 2 foals (2/102, 1.96% of the horses). Salmonella organisms were not isolated from the mesenteric lymph nodes of adult horses. CONCLUSIONS AND CLINICAL RELEVANCE: Prevalence of Salmonella infections in horses of our study (1.96%) suggests that the results of cross-sectional surveys, using bacteriologic culture to determine prevalence of Salmonella infection, should be interpreted with caution. Prevalence of Salmonella infections determined in a single facility may not reflect the prevalence of Salmonella-infected horses in the general population; furthermore, obtaining a Salmonella isolate from a horse does not establish that the horse is a chronic Salmonella carrier.     

A new method for evaluation of the resistance to rice kernel cracking based on moisture absorption in brown rice under controlled conditions

We developed and evaluated the effectiveness of a new method to detect differences among rice cultivars in their resistance to kernel cracking. The method induces kernel cracking under laboratory controlled condition by moisture absorption to brown rice. The optimal moisture absorption conditions were determined using two japonica cultivars, ‘Nipponbare’ as a cracking-resistant cultivar and ‘Yamahikari’ as a cracking-susceptible cultivar: 12% initial moisture content of the brown rice, a temperature of 25°C, a duration of 5 h, and only a single absorption treatment. We then evaluated the effectiveness of these conditions using 12 japonica cultivars. The proportion of cracked kernels was significantly correlated with the mean 10-day maximum temperature after heading. In addition, the correlation between the proportions of cracked kernels in the 2 years of the study was higher than that for values obtained using the traditional late harvest method. The new moisture absorption method could stably evaluate the resistance to kernel cracking, and will help breeders to develop future cultivars with less cracking of the kernels.     

早籼稻近缘系的主要农艺性状与SSR标记鉴定

以早籼稻浙106与近缘系浙205、浙206和浙207共4个品种(系)为研究对象,利用农艺性状为观测指标的形态标记鉴定技术和简单重复序列(SSR)分子标记鉴定技术对4个品种(系)的农艺性状和基因组DNA进行性状考查。结果表明:4个材料具有各自所特有的外观形态标记,但只运用农艺性状的观察很难来鉴定浙106与近缘系,选用的32对引物中有13对引物在品种(系)间表现明显的多态性特征,SSR标记结合形态标记用于近缘系间的品种鉴别较为合适。     

Molecular identification of macroalgal fragments in gut contents of the sea urchin <Emphasis Type="Italic">Hemicentrotus pulcherrimus</Emphasis>

In order to improve the efficiency of stock enhancement programs for the sea urchin Hemicentrotus pulcherrimus, information on food algal species, which affect growth and gonad production greatly, is necessary. Since it is difficult to identify species from the macroalgal fragments within the gut contents of the sea urchin by microscopic observation, we tried to apply a DNA barcoding method for gut contents analysis. We used a partial rbcL gene sequence for taxonomic section and newly designed primer sets, respectively, for brown algae and for red algae. Direct sequencing of the PCR products was carried out. Species identification was based on the phylogenetic relationship. We could objectively identify four species and two taxonomic groups (genus or family) in brown algae, and two species and four taxonomic groups in red algae from the gut contents. Sargassum hemiphyllum was the most abundant brown alga in the gut contents but was not dominant in the study site. The result showed the importance of identification to the species level. In addition, red algal epiphytes were detected with brown algal fragments. The DNA barcoding method will enable the researchers to verify the important role of epiphytes as a potential food source.     

The use of tetracycline in anthelmintic baits to assess baiting rate and drug efficacy against Echinococcus multilocularis in foxes

Anthelmintic (praziquantel) baiting of wild red foxes against Echinococcus multilocularis infection was studied in a highly epizootic suburban area of Otaru, Hokkaido (the northern island of Japan) during the summer and autumn in the years 1999-2004. Acceptance of baits containing the biomarker tetracycline (TC) was evaluated. The prevalence of E. multilocularis infection in foxes before baiting (1999-2000) was 58% (88/153), whereas in the fourth year of bait distribution year (2004), it decreased to 11% (5/45). Analysis of TC marking in the teeth of foxes showed that 39% (77/195) of those captured after baiting were estimated to have consumed baits in the year of capture. Importantly, more juvenile (56%, 49/87) than adult foxes (26%, 28/108) were marked, indicating efficient baiting of juveniles, which tended to have a higher worm burden of E. multilocularis. Of 77 marked foxes, E. multilocularis and Alaria alata (monitored as the second indicator species of deworming) were not detected in 70 (90%) and 76 (99%) foxes, respectively. The results suggest effective deworming by bait consumption. However, it was also demonstrated that 9% of the marked foxes were infected or re-infected after bait consumption, suggesting high infection pressure and the importance of frequent baiting.