Some motile properties of fast characean myosin

We improved a motility assay system by using an affinity-purified antibody against the C-terminal globular domain of characean myosin. This improvement allowed us to study the sensitivity to ionic strength or the processivity of characean myosin. The sliding velocity of actin filaments on a characean myosin-coated surface was unaffected by ionic strength. This property is unlike that of skeletal or smooth muscle myosin and suggests that the binding manner of characean myosin to actin is different from that in other muscle myosins. The sliding velocity decreased when the MgADP concentration was raised. The extent of inhibition by MgADP on the motile activity of characean myosin was almost the same as in skeletal muscle or cardiac myosin. The number of sliding filaments on the characean myosin-coated surface decreased drastically with a decrease in the motor density. The motor density required to produce a successful movement of actin filament was about 200 molecules/microm(2). These results suggest that the characean myosin is not a processive motor protein.     

Genera and species of Baetidae in Japan: <Emphasis Type="Italic">Nigrobaetis,Alainites, Labiobaetis</Emphasis>, and <Emphasis Type="Italic">Tenuibaetis</Emphasis> n. stat. (Ephemeroptera)

We describe morphological characters of the genera Nigrobaetis, Alainites, Labiobaetis, and Tenuibaetis n. stat. and provide generic situations of six Japanese species: Nigrobaetis chocoratus n. comb., N. sacishimensis n. comb., Alainites atagonis, A. florens, A. yoshinensis, and Tenuibaetis pseudofrequentus. To evaluate the polarities of the morphological characters and the monophyly of Nigrobaetis, Alainites, Labiobaetis, and Tenuibaetis, character states of these four genera were compared with the genus Cloeon as an outgroup. Labiobaetis is considered to be a monophyletic group supported by a wide paraglossa. Tenuibaetis is a monophyletic group that is distinguishable from the related genera by robust setae with a medial ridge on the dorsomedian surface of the nymphal femur. We did not find any synapomorphic characters of Nigrobaetis or Alainites. Although we tentatively treat Nigrobaetis and Alainites as distinct genera, they are considered to be paraphyletic taxa.     

Labiobaetis species of Japan, Taiwan, and Korea, with a new synonym of L. atrebatinus (Eaton 1870) and reerection of the subspecies L. atrebatinus orientalis (Kluge 1983) (Ephemeroptera, Baetidae)

We associated nymphs of Labiobaetis sp. G and Labiobaetis sp. Q from Japan with imagoes reared from nymphs in the field. Labiobaetis sp. G was identified with L. atrebatinus (Eaton 1870) based on characters of the reared male and female imagoes, nymphs, and eggs. We also synonymized a Taiwanese species, L. morus (Chang and Yang 1994), with L. atrebatinus. After further examination of the characters of male imagoes from Japan and Korea and nymphs from Japan and Taiwan, we found them to be correspondent to subspecies L. atrebatinus orientalis (Kluge 1983). Thus, we reerected the subspecific status of L. a. orientalis, although it had been considered not distinguishable from the nominotypical subspecies L. a. atrebatinus. Labiobaetis a. orientalis is distributed in the Russian Far East, Japan, Korea, and Taiwan. We identified Labiobaetis sp. Q with L. tricolor (Tshernova 1928) based on characters of the reared male and female imagoes, nymphs, and eggs. Labiobaetis tricolor was recorded from Japan for the first time.     

Carbon-carbon bond cleavage of fucosterol-24, 28-oxide by cell-free extracts of silkworm Bombyx mori.

The 1500 X g supernatant of the silkworm $\text{Bombyx mori}$ gut homogenate catalyzed the conversion of 24, 28-epoxystigmast-5-en-3β-ol(III) to cholesta-5, 24-dien-3β-ol(IV) which is a key step of stigmast-5-en-3β-ol(I) dealkylation in the insects. A structural analog 24, 28-imino-stigmast-5-en-3β-ol(VI) was a potent inhibitor of this conversion.     

Local increase in trapezius muscle oxygenation during and after acupuncture

Purpose

This study aimed to compare the trapezius muscle blood volume and oxygenation in the stimulation region and in a distant region in the same muscle during acupuncture stimulation (AS). We hypothesized that AS provokes a localized increase in muscle blood volume and oxygenation in the stimulation region.

Methods

Two sets of near-infrared spectrometer (NIRS) probes, with 40-mm light-source detector spacing, were placed on the right trapezius muscle, with a 50-mm distance between the probes. Changes in muscle oxygenation (oxy-Hb) and blood volume (t-Hb) in stimulation and distant regions (50 mm away from the stimulation point) were measured using NIRS. Nine healthy acupuncture-experienced subjects were chosen as the experimental (AS) group, and 10 healthy acupuncture-experienced subjects were chosen for the control (no AS) group. Measurements began with a 3-min rest period, followed by "Jakutaku" (AS) for 2 min, and recovery after stimulation.

Results

There was a significant increase in oxy-Hb (60.7 μM at maximum) and t-Hb (48.1 μM at maximum) in the stimulation region compared to the distant region. In the stimulation region, a significant increase in oxy-Hb and t-Hb compared with the pre-stimulation level was first noted at 58.5 s and 13.5 s, respectively, after the onset of stimulation.

Conclusion

In conclusion, oxygenation and blood volume increased, indicating elevated blood flow to the small vessels, not in the distant region used in this study, but in the stimulation region of the trapezius muscle during and after a 2-min AS.

     

A study of passive weight-bearing lower limb exercise effects on local muscles and whole body oxidative metabolism: a comparison with simulated horse riding,bicycle, and walking exercise

Background

We have developed an exercise machine prototype for increasing exercise intensity by means of passively exercising lower limb muscles. The purpose of the present study was to compare the passive exercise intensity of our newly-developed machine with the intensities of different types of exercises. We also attempted to measure muscle activity to study how these forms of exercise affected individual parts of the body.

Methods

Subjects were 14 healthy men with the following demographics: age 30 years, height 171.5 cm, weight 68.3 kg. They performed 4 types of exercise: Passive weight-bearing lower limb exercise (PWLLE), Simulated horse riding exercise (SHRE), Bicycle exercise, and Walking exercise, as described below at an interval of one week or longer. Oxygen uptake, blood pressure, heart rate, and electromyogram (EMG) were measured or recorded during exercise. At rest prior to exercise and immediately after the end of each exercise intensity, the oxygenated hemoglobin levels of the lower limb muscles were measured by near-infrared spectroscopy to calculate the rate of decline. This rate of decline was obtained immediately after exercise as well as at rest to calculate oxygen consumption of the lower limb muscles as expressed as a ratio of a post-exercise rate of decline to a resting one.

Results

The heart rate and oxygen uptake observed in PWLLE during maximal intensity were comparable to that of a 20-watt bicycle exercise or 2 km/hr walking exercise. Maximal intensity PWLLE was found to provoke muscle activity comparable to an 80-watt bicycle or 6 km/hr walking exercise. As was the case with the EMG results, during maximal intensity PWLLE, the rectus femoris muscle consumed oxygen in amounts identical to that of an 80-watt bicycle or a 6 km/hr walking exercise.

Conclusion

Passive weight-bearing lower limb exercise using our trial machine could provide approximately 3 MET of exercise and the thigh exhibited muscle activity equivalent to that of 80-watt bicycle or 6 km/hr walking exercise. Namely, given the same oxygen uptake, PWLLE exceeded bicycle or walking exercise in muscle activity, thus PWLLE is believed to strengthen muscle power while reducing the load imposed on the cardiopulmonary system.

     

Salmon cartilage proteoglycan suppresses mouse experimental colitis through induction of Foxp3+ regulatory T cells

Proteoglycans (PGs) are complex glycohydrates which are widely distributed in extracellular matrix (ECM). PGs are involved in the construction of ECM, cell proliferation and differentiation. ECM components are involved in transduction of proinflammatory responses, but it is still unknown whether PGs are involved in inflammatory response. In this study, we investigated the effect of PG extracted from salmon cartilage on the progression of experimental colitis-induced in severe combined immunodeficiency mice by cell transfer from interleukin-10 (IL-10)^−/− mice. IL-10^−/− cell-transferred mice showed weight loss, colon shortening and histological appearance of mild colitis. Daily oral administration of PG attenuated the clinical progression of colitis in a dose-dependent manner. Colitis-induced mice showed the elevated expression of IFN-γ, IL-12, TNF-α, IL-21, IL-23p19, IL-6, IL-17A and retinoic acid-related orphan receptor γt (RORγt) in lamina propria mononuclear cells (LPMCs) and oral administration of PG suppressed the expression of these factors. Conversely, expression of Foxp3 that induces CD4⁺CD25⁺ regulatory T cells in LPMCs was enhanced by PG administration. These findings suggested that salmon PG attenuated the progression of colitis due to suppression of inflammatory response by enhancement of regulatory T cell induction.     

Bower‐building behaviour is associated with increased sperm longevity in Tanganyikan cichlids

We investigated the evolutionary relationship between spawning behaviour and sperm motility traits among Tanganyikan mouth‐brooding cichlid species that have developed diverse mating behaviours and male sexual traits. Mouth‐brooding behaviour is common among these fish, but different species demonstrate a range of spawning behaviours, bower construction, male sexual traits and timing of gamete release. We observed spawning behaviours and compared sperm motility traits of 28 Tanganyikan mouth‐brooding cichlids to elucidate the evolutionary correlations between these traits. Sperm longevity was considerably longer in bower‐building species that construct crater‐shaped spawning sites compared with species that do not build bowers. Male bower builders released sperm in the pit of the bower prior to spawning, and the time from ejaculation to fertilization was longer. Conversely, most mouth‐brooding cichlids deposited semen directly into the female buccal cavity, and spawned eggs were immediately picked up to be placed inside the cavity; thus, the time from ejaculation to fertilization was short. These observations suggest that increased sperm longevity is favoured in bower builders. Comparative phylogenetic analyses suggested that bower‐building behaviour and greater time from ejaculation to fertilization are associated with the extension of sperm longevity, whereas sperm competition rank does not play a major role. In addition, bower‐building behaviour preceded the emergence of increased sperm longevity. These results indicate that the extension of sperm longevity as a result of the emergence of bower builders may have acted as an evolutionary attractor for sperm longevity.