REPRODUCTIVE ISOLATION BY HOST SPECIFICITY IN A PAIR OF PHYTOPHAGOUS LADYBIRD BEETLES

Crossing experiments and food-choice tests show that two sympatric species of phytophagous ladybird beetles, Epilachna niponica and E. yasutomii, are reproductively isolated by host-plant specificity. Adult beetles selected their natural hosts when given choices, though some accepted the host of the other species when no choice was offered. In each species, survival of larvae to the second instar was significantly higher on their own host plant. No evidence for sexual isolation, gametic isolation, hybrid inviability, or reduced hybrid fertility was detected. Reproductive isolation by host specificity is an important prerequisite for certain models of sympatric speciation. Although the present example supports the plausibility of such models, an allopatric origin of host-plant specificity cannot be discounted.     

Potential Distribution and Ionic Concentration at the Bean Root Surface of the Growing Tip and Lateral Root Emerging Points

The electrical potential distribution has been measured preciselyaround the root surface of the bean sprout Vigna mungo (L) Hepper.A large negative potential well was found at the growth portionof the root tip. Also, in the matured region of the root, wefound a negative potential well at an unspecified position inspite of the fact that nothing was detected on the smooth surface.A lateral root emerge was found to have initiated after 15–20hours just at the position corresponding to the potential well.With the expectation that these potentials can be elucidatedbased on the transport of ions which are released or absorbedby the root as a result of cell activity, we precisely measuredthe concentrations of major ion species (K⁺, H⁺, and Cl^–)around the root. The theoretical potential distribution curvesobtained by putting all the concentration data into the Henderson'sEquation for a liquid junction (diffusion) potential coincidedwell with the experimental curves. (Received October 24, 1994; Accepted March 24, 1995)     

Entrainment of the circadian locomotor activity rhythm in the Japanese newt by melatonin injections

We examined whether melatonin can act as a synchronizing agent within the circadian system of amphibians by testing the ability of melatonin injections to entrain the circadian locomotor activity rhythm of a newt (Cynops pyrrhogaster). Under constant darkness, all newts (13 cases) showing the free-running rhythms were subcutaneously injected with 10 g melatonin at the same time every other day for at least 30 days. Subsequently, they were injected with vehicle (1% ethanolic saline) instead of melatonin for at least another 30 days. In 10 of the 13 newts, the locomotor activity rhythms could be entrained to a period of 24 h by melatonin injections but not by vehicle injections. During the entrained steady-state, the active phase of an activity-rest cycle preceded the time of melatonin injections as previously reported in other diurnal species. These results suggest that the endogenous circadian rhythm of melatonin concentration may be involved in synchronizing circadian oscillator(s) within the newt's circadian system.     

Immune response induced by live attenuated varicella vaccine and short term follow-up on immunity of the vaccinated children

Live attenuated varicella vaccine (Oka strain, 500 to 750 PFU) was inoculated into 234 children with various underlying diseases. Varicella-zoster virus (VZV) specific immune adherence hemagglutination antibody developed in 95% of initially seronegative subjects. VZV specific cellular immune responses were detected in 91% of subjects within 6 weeks after vaccination. A preliminary survey of 46 vaccinated normal-risk subjects during the first and the third year revealed excellent protection with the exception of one case who had not shown any antibody response at the fourth week.     

A new biologically active phenolic from Cattleya trianaei

A new phenolic, hydroxyeucomic acid, and dopamine were isolated from Cattleya trianaei and their biological activities examined.     

Effect of furosemide on urinary excretion of prostaglandin E in normal volunteers and pateints with essential hypertension

Urinary excretion of prostaglandin E was measured radioimmunologically in 19 healthy persons ( 15 men and 4 women ) and in 16 patients ( 10 men and 6 women ) with essential hypertension before and after the administration of furosemide. The excretion rates were increased from 26.3±3.0 to 64.5±11.3 ng/hr in the former and from 11.9±2.7 to 26.9±85 ng/hr in the latter. There was a significant difference between them, healthy subjects showing a greater increase than patients with essential hypertension.There was an obvious sexual difference in urinary excretion of prostaglandin. In men, greater increase in the excretion rates was found than in the women. Greater increases were also obtained in healthy men than in hypertensive men and in healthy women than in hypertensive women. The present results suggest that furosemide enhances urinary excretion of prostaglandin E by mechanisms which entails either an increase in prostaglandin synthesis or a decrease in renal metabolism.     

A Waldenstr?m's macroglobulin with anti-G3m(b1) antibody activity.

A human monoclonal macroglobulin (IgM, K) from a patient (KI) with Waldenstr?m's macroglobulinemia was shown to have antibody activity against a human IgG (Gm) allotype. In hemagglutination tests, only one anti-D serum with G3m(b0b1) reacted with macroglobulin KI. Antiglobulin specificity of macroglobulin KI was determined to be an anti-G3m(b1) antibody by hemagglutination inhibition tests. Fab fragments from macroglobulin KI could react with human IgG3 protein possessing G3m(b1), but Fc fragments could not react. Gm phenotype in IgG isolated from serum KI was determined to be Gm(a,z,g,b0,s,t,u). This is the first report of a Waldenstr?m's macroglobulin with antiglobulin specificity against a Gm allotype.     

Central effects of yohimbine on copulatory behavior in aged male rats

It is well known that yohimbine has a history of popular use because of its supposed aphrodisiac properties. The present study was done to determine whether yohimbine can modify the copulatory behavior of aged male rats. Adult male rats of the Wistar-Imamichi strain, 52 weeks of age and weighing 600-650g, were injected intracerebroventricularly with yohimbine hydrochloride (5, 10 micrograms/10 microliters/rat) or vehicle. Each male was then given the opportunity to mate with a receptive female for 30 min after administration of yohimbine or vehicle. Yohimbine produced significant decreases in the latency to initial mounting and significant increases in the number of mountings. However, there was no ejaculation in the yohimbine-and vehicle-treated males. This study is the first to clearly establish an important modulator of sexual arousal for yohimbine in aged male rats.