Efficient Method for Analysis of QTL Using F1 Progenies in an Outcrossing Species

In the present paper, we proposed a statistical procedure based on composite interval mapping for accurate analysis of quantitative trait loci (QTL) for individuals sampled from an outcrossing population with two-generation families consisting of the sampled individuals and F1 progenies obtained by crossing them as parental individuals. In the proposed procedure, haplotypes of markers of parental individuals were reconstructed based on the genotypes of F1 progenies and QTL analyses with composite interval mapping were conducted separately for each of parents as well as jointly for both parents. A least squares method was applied to the composite interval mapping, where some of markers were selected as cofactors to absorb the variation induced by QTL located elsewhere in the genome. The procedure was evaluated for the efficiency in detecting QTL and the precision of estimates of locations and effects of QTL using simulations. It was shown that QTL with interaction between paternal and maternal alleles was effectively detected by joint analysis of both parents, while a QTL segregating only in one parent, closely linked to a QTL segregating only in the other parent, was successfully detected by analyzing separately each of the parents with inclusion of markers of both parents. The proposed procedure can provide detailed genetic information useful for marker assisted breeding in an outcrossing species such as forest trees.     

Characterization of N-methyl-D-aspartate receptor subunits involved in acute ammonia toxicity

Rapid administration of large doses of ammonia leads to death of animals, which is largely prevented by pretreatment with N-methyl-D-aspartate (NMDA) receptor antagonists. The present study focuses on a subunit(s) of NMDA receptor involved in ammonia-induced death by use of NMDA receptor GluRepsilon subunit-deficient (GluRepsilon(-/-)) mice and the selective GluRepsilon2 antagonist CP-101,606. Acute ammonia intoxication was induced in mice (eight per group) by a single intraperitoneal (i.p.) injection of ammonium chloride. Appearance of neurological deteriorations depended on the doses of ammonium chloride injected. While wild-type, GluRepsilon1(-/-), GluRepsilon4(-/-), and GluRepsilon1(-/-)/epsilon4(-/-) mice all died by ammonium chloride at 12 mmol/kg during the first tonic convulsions, two of eight GluRepsilon3(-/-) mice survived. Pretreatment of wild-type mice with CP-101,606 prevented two mice from ammonia-induced death. Pretreatment of GluRepsilon3(-/-) mice with CP-101,606 prevented the death of three mice and prolonged the time of death of non-survivors. Similarly, the neuronal form of nitric oxide synthase (NOS) inhibitor 7-nitroindazole (7-NI) as well as the nonselective NOS inhibitor L-NMMA, but not the inducible NOS inhibitor 1400W, partially prevented the death of mice and prolonged the period of death. Furthermore, ammonium chloride prolonged the increase in intracellular free Ca2+ concentration ([Ca2+]i) and subsequent NO production induced by NMDA in the cerebellum. These results suggest that activation of NMDA receptor containing GluRepsilon2 and GluRepsilon3 subunits and following activation of neuronal NOS are involved in acute ammonia intoxication which leads to death of animals.     

Dynamics of sibling aggression of a cichlid fish in Lake Tanganyika

Hydrobiologia - Siblings often compete for limited resources, particularly food provided by their parents. Such competition is usually nonviolent, but direct aggression has evolved in some species....     

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.     

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.     

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.

     

Seasonal changes in reproductive and physical condition, sexual dimorphism, and male mating tactics in the jewelled blenny Salarias fasciatus

To investigate seasonal changes in reproductive and physical condition, sexual dimorphism, and mating tactics in the jewelled blenny Salarias fasciatus, monthly collections were conducted on the fringing reef in northern Okinawa, Japan. Monthly variation in the female gonadosomatic index suggested that the breeding season of this species is from April to June. The physical condition and hepatosomatic index of both sexes considerably deteriorated during the course of the breeding season. Such declines may be primarily due to egg production in females and brood care in males. Males’ elongated anal spines were longer than females’, but no other apparent sexual dimorphisms were detected, indicating that S. fasciatus exhibits a low degree of sexual dimorphism. Examinations of testes size and the testicular gland area during the estimated breeding season revealed that the gonadosomatic index values of smaller males did not differ from those of larger males. This result may differ from other blenny species that exhibit alternative male reproductive tactics. However, patterns of male testicular glands of S. fasciatus were similar to those of other blennies with alternative tactics, i.e., smaller males had poorly developed testicular glands compared with larger males.