Kazumi Tagami

Occurrence of aquatic oribatid and astigmatid mites in swimming pools

Abstract The geographic distribution, density, species composition, food habits and route of invasion of aquatic oribatid and astigmatid mites in swimming pools were studied. These animals occurred in 53% of the indoor swimming pools tested. Oribatids were found only in a restricted area, while astigmatids were widely distributed throughout Japan. The identified species were Hydronothrus crispus Aoki in four pools, Trimalaconothrus maniculatus Fain et Lambrechts in four and Histiostoma ocellatum Fain et Lambrechts in 15 of 36 pools. Mite faunas were usually very simple, being of a single species; if other species were found to co-exist they were few in number. The highest density determined by our tests was less than 50 individuals/m 2 . To clarify the route of invasion to the pools, 50–100 m 3 of the water entering a pool was screened through a nylon mesh. Mites found in the residue on the screen were of the same species as those found in the swimming pools.

Muscle glycogen repletion and pre-exercise glycogen content: effect of carbohydrate loading in rats previously fed a high fat diet

We have recently reported that rates of muscle glycogen repletion during the early period of recovery were increased by carbohydrate (CHO) loading in rats previously fed a high fat diet. However, the reason for this remained unanswered. The purpose of this study was to examine whether an increase of glycogen utilization due to an elevated pre-exercise glycogen store would enhance rates of glycogen repletion in muscle. Despite an equal degree of glycogen depletion, the rates of glycogen repletion of soleus, red and white gastrocnemius muscles by postexercise administration of glucose (3.0 g · kg−1 body mass) and citrate (0.5 g · kg−1 body mass) were faster in the CHO loaded (3 days) rats than in the nonloaded rats, as a result of elevated pre-exercise glycogen content and consequently the greater glycogen utilization. The higher rate of muscle glycogen repletion may in part be explained by increased postexercise glycogen synthase activity.

Exercise-induced liver β2-microglobulin expression is related to lower IgG clearance in the blood

Voluntary wheel running exercise induced higher antigen-specific IgG in circulating blood is well recognized in mice. This antibody response may be regulated by an exercise-induced mechanism that protects against IgG catabolism. The recent hypothesis that the beta2-microglobulin gene is implicated in IgG protection is investigated further on mice voluntary wheel running. Male C57BL/6N mice were intraperitoneally immunized with 0.375microg/kg (body weight) of tetanus toxoid to induce primary and secondary antibody responses. At the peak concentration of blood tetanus toxoid specific IgG in this experiment, we administered (125)I-labeled mouse IgG. To determine how (125)I-IgG half-life is prolonged in voluntary wheel running exercised mice, we observed the tissue radioactivity (125)I-IgG. Significantly higher blood IgG concentrations were demonstrated in the exercised group compared to non-exercised group (P<.05). The mean value of radioactivity in the liver was higher in the exercised group (P<.05). Furthermore, extracted IgG concentration of exercised mouse liver was higher than that of non-exercised group (P<.05). Immunohistochemical analysis showed dramatically increased tissue IgG in the liver of the exercised group (P<.05). The gene expression of beta2-microglobulin was up-regulated in the exercised mouse liver (P<.05). There is a significant correlation between liver accumulation of (125)I-IgG and (125)I-IgG concentration in the blood (P<.05). In addition, there is a significant correlation between extracted total hepatic IgG and beta2-microglobulin in the liver (P<.05). These findings indicate that voluntary wheel running exercise-induced liver beta2-microglobulin expression is related to lower IgG clearance in the blood.

Effects of short-term dietary change from high fat to high carbohydrate diets on the storage and utilization of glycogen and triacylglycerol in untrained rats

The effects of short-term diet change from high fat (F) to high carbohydrate (C) (or vice versa) on the storage and utilization of glycogen and triacylglycerol (TG) in muscle and liver were studied in untrained rats. Rats were fed on an F or C diet for 28 days. For an additional 3 days, half of the rats in both F and C groups were fed the same diets as before (F-F and C-C) and the other half of the rats were switched to the counterpart diets (F-C and C-F). On the final day of the experiment, half of the rats in each diet group were exercised by swimming for 1.5 h and the other half were rested. Short-term diet change from F to C diets increased, but the change from C to F diets decreased, glycogen stores of soleus and plantaris muscles and liver, resulting in no difference in glycogen stores between F-C and C-C, and between F-F and C-F. The dietary change also had an affect on TG stores of red gastrocnemius muscle and liver - however, muscle TG stores were still higher in F-C than in C-C and C-F, and there were no differences in liver TG stores between F-C and C-F. Exercise decreased muscle glycogen contents markedly in F-C and C-C, whereas, it decreased muscle TG concentrations in F-F and C-F. Liver glycogen depletion was lower in F-C than in other groups. Lipolytic activities of epididymal adipose tissue at rest and postexercise were no differences between F-F and F-C, and were higher in F-C than in C-C and C-F. β-adrenergic receptor binding was determined with [125I] iodocyanopindolol, and maximal numbers of β-adrenergic receptor of plasma membrane from perirenal adipose tissue were approximately 170%–200% higher in F-C than in other groups at rest and postexercise. These results suggested that short-term C diet fed rats adapted to F diet enhanced not only glycogen stores of muscle and liver but also did not decrease lipolytic activity of adipose tissue with increased β-adrenergic receptor density, resulting in the preservation of energy reserves (glycogen and TG) of muscle at rest, and liver glycogen sparing during exercise.

Effect of exercise on bone status and body composition in Japanese students

PURPOSE We evaluated the effect of exercise on stiffness and fat-free mass (FFM), which consists of bone and muscle, in Japanese students. It is uncertain whether exercise or sports activities will help to accumulate overall peak bone mass in Japanese adolescents. METHODS A total of 710 Japanese students (age = 15-20 yr) were enrolled. Students who regularly engage in physical exercise were assigned to an exercise group; other students were assigned to a nonexercise group. Body composition, including height, weight, waist circumference, hip circumference, body mass index, and waist-to-hip ratio, were measured and calculated. Lung volume, body volume, and body fat percentage were evaluated by air displacement plethysmography. Fat mass and FFM were derived from body fat percentage and body weight. Bone status, such as speed of sounds, broadband ultrasound attenuation, and stiffness, which is defined as bone density, was assessed by quantitative ultrasound. RESULTS In both sexes, height, weight, body mass index, circumferences, waist-to-hip ratio, lung volume, and body volume between the exercise and nonexercise groups did not show any significant differences. FFM, speed of sounds, broadband ultrasound attenuation, and stiffness in the exercise group were statistically higher than those in the nonexercise group (P < 0.05). Although stiffness positively correlated with age with the exception of the nonexercise group in females (P < 0.01), stiffness correlated with FFM in the exercise and nonexercise groups in both sexes (P < 0.01). CONCLUSIONS Ours is the first analysis of a trend in peak bone mass, including the effect of exercise in Japanese students. For Japanese pubertal females who did not have a history of regular exercise, stiffness slowly decreased with age. Exercise habits in early childhood are important in the relationship between stiffness and FFM.

Description of adults and redescription of deutonymphs of Histiostoma darwishii Eraky, 1994 (Astigmata: Histiostomatidae), an associate of Parasitus fimetorum Berlese (Mesostigmata: Parasitidae)

Abstract Histiostoma darwishii Eraky (Astigmata: Histiostomatidae) was studied from a culture of a mesostigmatid mite (Parasitus fimetorum Berlese, 1903, Mesostigmata: Parasitidae), collected from compost at the Hokkaido University Experimental Farm in 1997. The morphological characters of the deutonymphs were identical to those of Histiostoma darwishii Eraky, 1994, recorded from an animal farm of the College of Agriculture, Assiut, Egypt. The adult male and female are described and illustrated for the first time, and the deutonymph is redescribed.

Inhibition of the Mitochondrial Complex I Activity by Fatty Acid Derivatives of Vanillylamide

Fatty acid derivatives of vanillylamide were found to inhibit the mitochondrial NADH oxidase activity, but almost not the succinate oxidase activity. These results suggest that the compounds are specific inhibitors of the Complex I activity. A study using purified Complex I demonstrated that the compounds inhibit NADH-coenzyme Q reductase activity of the enzyme. However, these did not inhibit rotenone-insensitive NADH-menadione reductase activity and electron transfer from NADH through iron-sulfur centers in Complex I. Kinetic analyses with double-reciprocal plots showed that these compounds were competitive inhibitors with respect to coenzyme Q1. These findings suggest that the compounds bind to the coenzyme Q binding site of Complex I. The natures of acyl groups greatly affected the inhibitory potencies of the compounds, suggesting that the acyl group of compound is important for the binding of compound to the binding site of Complex I.