Two Ophiostoma species associated with bark beetles in wave-regenerated Abies veitchii forests in Japan

Two species of Ophiostoma were isolated from four bark beetles (i.e., Cryphalus montatus, C. piceae, Dryocoetes hectographus, and Polygraphus proximus) infesting Abies veitchii and from their galleries in the wave-regenerated forests in the central part of the main island (Honshu) of Japan. One of them is described here as a new species, Ophiostoma subalpinum, and the other is identified as O. davidsonii, newly reported in Japan. Ophiostoma subalpinum is characterized by short ostiolar hyphae, oblong or allantoid ascospores enclosed in a thin, hyaline sheath, and a Pesotum anamorph. Received: June 4, 2001 / Accepted: December 25, 2001     

Effects of phenylmethylsulphonylfluoride on activities of cholesteryl ester synthesis and hydrolysis in testes of rats, and on serum testosterone and LH levels.

PMSF was injected subcutaneously to male rats once a day for 10 days at a dose of 10 mg/day. There was an increase in the concentrations of free and esterified cholesterol in the testes, a decrease in activities of cholesteryl ester synthesis and hydrolysis but no change in activity of cholesterol side-chain cleavage enzyme. Serum testosterone and LH levels were significantly decreased. The only effect of PMSF on the lipids of the testes was a marked elevation of docosapentaenoic (22:5) acid and the cholesteryl esters.     

Taste-enhancing effects of glycine on the sweetness of glucose: a gustatory aspect of symbiosis between the ant, Camponotus japonicus, and the larvae of the lycaenid butterfly, Niphanda fusca.

The lycaenid butterfly, Niphanda fusca, has a parasitic relationship with its host ant, Camponotus japonicus: the caterpillars may use chemical mimicry to enter the ant nest where they are fed mouth-to-mouth by the adult ants until pupation. Nevertheless, larvae offer their host ants a nutritious secretion that contains 160 mM glucose and 43 mM glycine. Using glucose and glycine mixture as artificial secretions, we investigated the gustatory effect of glucose and/or glycine on the ants. Glycine induced neither feeding behavior nor gustatory response in the ants if its concentration was <500 mM. In the presence of glycine at the concentration in the secretion, however, the ants improved their preference to glucose, and the sugar receptor cell exhibited electrophysiological enhancement of response to glucose in a glycine-concentration-dependent manner. By adding glycine to glucose in their secretions, therefore, the butterfly larvae can manipulate the gustatory sense of the ants. The alluring taste of 'glycine-flavored glucose' could motivate the host ants to feed the larvae and thereby receive the secretions as a reward. The taste enhancement created by the combination of sugar and amino acid may play a role in the evolution of the parasitic relationships of these insects. The taste-enhancing effect appears to be analogous to taste enhancement by 'umami' substances in humans.     

Spectroscopic and equilibrium dialysis studies of poly(α-L-glutamic acid)–Cu(II) complexes in the pH range 4–7

The formation of complex between the Cu²⁺ ion and poly(α-L -glutamic acid) [poly(Glu)] in 150 mM NaCl solutions was studied by uv–visible absorption and equilibrium dialysis methods at the mixing ratios of Glu residues to Cu²⁺, R, of 32, 16, and 8 and in the pH range 4–7. The results showed that more than 90% of Cu²⁺ ions bind to the poly(Glu) at pH > 4.9, but the bound Cu(II) begins to dissociate with a decrease in pH. The absorption spectra of bound Cu(II) varied with pH and R in a complicated manner. Three different component spectra were disclosed from the analysis of the pH dependence of the bound spectra. We concluded that poly(Glu)–Cu(II) complexes fall into three classes in the pH range 4–7, with the proportions of these complexes varying with both pH and R. The three complexes predominate either in the helix or extended-coil region, in the helix–coil transition region, or in the helix-aggregate region. The stability constant and binding mode of each Cu(II)–Glu complex were estimated from the dialysis data. With these results, the possible structure of each complex is discussed.     

Population dynamics of movable genetic elements in Japanese natural populations of Drosophila melanogaster. I. Microevolution of male recombination determinants in experimental populations

Five natural populations of D. melanogaster in Japan were surveyed for male recombination frequency in terms of the quantities of the mean and variance after crossing with cn bw females. The experimental condition enabled P-M system hybrid dysgenesis to take place. The means were not so different from one another, but there was a vast variation in the variances between them. Using one of these populations, two additional experimental populations were started, and the male recombination frequencies were monitored for 30 generations. Both the means and variances decreased in value at 25 degrees C. The regression line was Y = -0.000030X + 0.001706 on generation for the mean values, and was Y = -0.000098X + 0.005068 for the standard deviations in the cage population. There was no correlation between the means or the standard deviations and the copy numbers of the members of P element family as a whole. The experimental results indicate that the complete P transposable elements still retained in population were decreased in frequency and replaced by its degenerative nonautonomous forms.