Evaluation of novel sulfonylurea derivatives with a fused heterocyclic moiety as paddy herbicides that control sulfonylurea‐resistant weeds

Herbicidal activity and acetolactate synthase (ALS) inhibition of sulfonylurea derivatives with a fused heterocyclic moiety bonded to a sulfonyl group were investigated. Some compounds that had an imidazo[1,2‐b]pyridazine moiety substituted at the 2‐position by chlorine or methyl controlled sulfonylurea‐resistant (SU‐R) weeds and showed inhibitory activity to ALS prepared from SU‐R Schoenoplectus juncoides shoot. There was a correlation between in vitro and whole‐plant herbicidal activity of the compounds mentioned above against SU‐R Schoenoplectus juncoides. Among them 1‐(2‐chloro‐6‐propylimidazo[1,2‐b]pyridazin‐3‐ylsulfonyl)‐3‐(4,6‐dimethoxypyrimidin‐2‐yl)urea, propyrisulfuron, was selected for further evaluation. Propyrisulfuron effectively controlled paddy weeds at doses of 70 and 140 g a.i. ha^?1 with good rice selectivity in a field trial.     

Inhibitory effect of enokitake extract on melanosis of shrimp

ABSTRACT:  The inhibitory effect of 70% acetone extract of enokitakemushroom Flammulina velutipes on the mealnosis of shrimp Trachypenaeuscurvirostris was investigated. The acetone extract effectivelyprevented the mushroom tyrosinase activity as well as melanosisof American crayfish Procambarus clarkii hemolymph. Wheneach of two fractions of the acetone extract, which were unadsorbedon both of Dowex 50W X8 and/or DEAE-TOYOPERAL 650 columns,was mixed with hemolymph of the American crayfish, the melanosisthat usually occurs in the heparinized hemolymph was effectivelyprevented. Immersing shrimp in the acetone extract of enokitakemushroom delayed the color darkening usually found in the post-mortemshrimp. These observations suggested that enokitake mushroom containedcertain compounds that inhibit the formation of melanin due to thecatalytic oxidation of polyphenol oxidase, as well as mushroom tyrosinaseactivity.     

Pathology of female mice experimentally infected with an in vitro cultured strain of Trypanosoma equiperdum

Dourine, caused by infection with Trypanosoma equiperdum, is one of the trypanosomiasis in equids. The clinical course of dourine is long-term, ranging from 1–2 months to several years. Since the pathogenesis of dourine has not yet been elucidated, experimental studies using mouse infection models are needed. Although mice are not susceptible to most T. equiperdum strains, some strains can infect mice. Even in such strains, infected mice develop rapidly transient parasitemia and die within 2–8 days. Therefore, mice experimentally infected with these T. equiperdum strains are not suitable for mouse infection models to analysis the pathogenesis of dourine. A sequential method of isolating parasites from dourine-affected horses and adapting them to in vitro cultures using soft agarose media was recently developed. Various T. equiperdum strains adapted to in vitro conditions have been established using this technique. We used one of these strains, the T. equiperdum IVM-t2 strain. In the present study, T. equiperdum IVM-t2 strain inoculated mice developed periodic parasitemia during the experimental period of 60 days. Histopathologically, vaginitis and dermatitis were observed. These findings were comparable to those of dourine-affected horses. Therefore, mice infected with T. equiperdum IVM-t2 strain may be a valuable tool for pathological, immunological, and parasitological in vivo research, and will contribute to investigations on the mechanisms underlying the disease process and the host-parasite relationship.     

Effects of aging and delivery order on the breeding capacity of F344/N rats

Reproductive performance affects the efficiency of the production of animals. Therefore, knowing the reproductive properties of each species or strain of animal is important for proper management of breeding stocks. To elucidate the reproductive properties of female F344/N rats, frequently used for longevity and gerontology research, we monitored the breeding duration, number of deliveries, litter size and weaning rate of their pups. The first delivery was observed at 2.9 ± 0.1 (mean ± standard deviation) months of age (M) and the last delivery was at 15.1 ± 1.8 M. The number of deliveries was 10.4 ± 2.8 (range of 7–16) within the life span of the mother (24.7 ± 5.6 M). The litter sizes at the third (10.0 ± 3.0) or fourth (10.3 ± 2.7) deliveries were higher than for other deliveries. The breeding outcome declined after the fifth delivery yielding reduced litter size or weaning rate, number of delivered mother. These results suggests that though female F344/N rats are able to deliver more than 10 times, the reproductive performance lowered after fifth delivery.