Effects of bicarbonate ions and pH on acquisition and maintenance of potential for motility in ayu, Plecoglossus altivelis Temminck et Schlegel (Osmeridae), spermatozoa

The effects of extracellular ions on the acquisition and maintenance of the potential for motility in the spermatozoa of the ayu, Plecoglossus altivelis Temminck et Schlegel (Osmeridae), were examined. Testicular spermatozoa and milt spermatozoa were obtained from fully matured males and diluted with buffered solution (BS, 20 mM HEPES–NaOH, pH 7.5). Testicular spermatozoa showed a significantly low rate of motility (0.8 ± 0.4%), whereas milt spermatozoa showed a high rate (89.4 ± 2.1%). The spermatozoa were incubated with various isotonic media for 2 h, diluted with BS, and changes in the rates of motility were then compared. When incubated for 2 h with artificial seminal plasma (ASP), corresponding in terms of ionic constituents to seminal plasma buffered at pH 8.0, both spermatozoa showed a high rate of motility. Testicular spermatozoa acquired and milt spermatozoa maintained the potential for motility in response to the HCO₃^– ion concentrations (between 0 and 20 mM) in the ASP. The differences in the pH of the ASP had a significant effect on the acquisition and maintenance of the potential for motility, and spermatozoa showed the highest rate of motility with the ASP at pH 8.0 and 8.5. These results suggest that the quality of milt in the ayu can be regulated by controlling the concentration of bicarbonate and the pH of the incubating media.     

Preparation of heavy meromyosin from the autolyzed squid mantle muscle homogenate

ABSTRACT:   Incubation of squid mantle muscle homogenate caused a selective cleavage of myosin into heavy meromyosin (HMM) and light meromyosin (LMM). HMM was isolated from the incubated homogenate by using ammonium sulfate fractionation. The purified HMM retained two types of light chain components. Its Mg²⁺-ATPase activity with or without F-actin showed a Ca-sensitivity. HMM was cleaved into subfragment-1 and subfragment-2 upon chymotryptic digestion with or without Ca²⁺, possessing different light chain composition. Two types of light chain component were kept intact when digested in the presence of Ca²⁺. Ca²⁺ stabilized HMM especially in a bound form to F-actin.     

Image-based phenotyping: use of colour signature in evaluation of melon fruit colour

Fruit colour, both external and internal, is important because it relates directly to the commercial value of the product. In breeding and in pre- and postharvest studies of fruit colour, an effective method for evaluating colour is needed to replace subjective evaluations by eye. We used a series of data processing and statistical analyses used in content-based image retrieval to evaluate melon flesh colour, and assessed the efficacy of this approach. This method relies on summarizing colour information from images into colour signatures, calculating the earth mover’s distance (EMD) between colour signatures, and multi-dimensional scaling (MDS) based on an EMD matrix. Performing MDS on a set of fruit flesh images revealed important colour features, such as the yellowish-green strength in green-fleshed melons and the relative size of the green and red parts in red-fleshed melons, without the need for an explicit definition of these features. The proportion of variance due to differences among cultivars was higher by MDS than by traditional evaluation, indicating that this new method performed best at detecting colour differences among cultivars. The method provides effective, objective indicators of fruit colour, and shows considerable promise for use in research and breeding programs.     

Effects of acquiring FSC forest management certification for Japanese enterprises using SmartWood Audits

We explore the organizational, environmental, and economic effects of sustainable forest management (FM) certification by Smart-Wood (SW), one of the certification bodies accredited by the Forest Stewardship Council (FSC) to carry out certification in Japan. We closely investigated three enterprises: the Yusuhara Forest Owners’ Cooperative, Yamanashi Prefectural Forest, and Ryujin-mura Forest Owners’ Cooperative. Interviews with representatives of these entities provided crucial empirical information regarding the influence of certification on environmental assessment, rare-species protection, landscape-management planning, management objectives, and forest supervision. Attainment of FM status improved environmental awareness and engendered positive changes in assessing and managing forests and other natural resources but simultaneously imposed heavier economic costs.     

Spatiotemporal distribution of barley and wheat plants naturally infected with bacterial black node in fields in western Japan

Bacterial black node caused by Pseudomonas syringae pv. syringae is the most serious bacterial disease of barley and wheat in Japan. The spatiotemporal distribution of barley and wheat plants infected with bacterial black node in fields in 2016–2017 was analyzed using Taylor’s model and Iwao’s model. In Taylor’s model, the sample variance (s ²) of the total and the newly diseased plants at each observation increased with mean plant density (m). In Iwao’s model, although the mean crowding (m*) of total and newly recognized diseased plants increased with m, Taylor’s model fit the data better than did Iwao’s model. Thus, bacterial black node could be explained as a colony expansion model.     

Oxidation and acetylation of sulfamonomethoxine by the snail Cepaea hortensis

Sulfamonomethoxine is not O-demethylated in the snail Cepaea hortensis, but acetylated (15.2%) and oxidised (0.78%) at the 2 position of the pyrimidine nucleus.     

Detection of endophyte toxins in the imported perennial ryegrass straw

From 1997 to 1999, 29 cases of disorders were detected in cattle and horses that had been fed ryegrass straw imported from the U.S.A. These animals showed symptoms resembling ryegrass staggers and the clinical signs disappeared after removal of the straw. Endophytic hyphae were detected in the seeds of all straw samples that were responsible for the clinical cases. Lolitrem B concentrations in the straw ranged between 972 and 3740 ppb. Ergovaline concentrations were between 355 and 1300 ppb. Even though the concentrations of lolitrem B were lower than the toxic threshold proposed by Oregon State University in better part of the cases, our observations suggest the possibility that lolitrem B lower than the proposed threshold can bring disorders to sensitive individuals.     

Synthesis and insecticidal and acaricidal activity of new N-(α-substituted phenoxybenzyl)-4-pyrimidinamines

A new class of insecticides and acaricides containing N-(α-substituted phenoxybenzyl)-4-pyrimidinamines as core structure were synthesized and their insecticidal and acaricidal potencies assessed. Among these, both the N-(3 or 4-phenoxybenzyl)-4-pyrimidinamine showed remarkable activity against diamondback moth, Plutella xylostella L., brown rice planthopper, Nilaparvata lugens (Stal) and two-spotted spider mite, Tetranychus urticae Koch. The potency of the new pyrimidinamines was particularly increased when a methyl, ethyl, iso-propyl, or cyclopropyl group was introduced at the α-position of benzyl moiety and it was evident that a single (+) optical isomer is more active than its antipode. Structure-activity relationships are discussed.     

Experimentally induced synovitis of chickens with Mycoplasma synoviae: effects of dexamethasone treatment.

Specific - pathogen - free chickens were inoculated in the right tibiometatarsal joint with a synovitis-derived Mycoplasma synoviae strain before or during dexamethasone treatment. Development of synovitis in chickens inoculated during the drug treatment was apparently delayed in comparison with development of synovitis in non-treated chickens. Severity of clinical synovitis in chickens inoculated before the drug was given was apparently less than that in chickens not treated or in chickens treated with dexamethasone. Histopathologic changes in the early stage of the infection (1 to 2 weeks) were not modified by dexamethasone treatment, although those changes in the succeeding stage (6 to 7 weeks) were greatly lessened. A relationship was observed between the dosage of dexamethasone and the severity of synovitis, as well as the kinds of cells that infiltrated into the joint lesions. Although serum antibody titers in chickens treated with an excessive dose of dexamethasone were markedly lower, clinical, bacteriologic, and histopathologic observations in chickens treated with dexamethasone were similar to those previously found in surgically thymectomized chickens. These results may support the theory that multiple synovitis of chickens caused by M synoviae infection develops mainly because of an immune response, especially by thymus-dependent functions.