Examination of the influences of density pressure on the pattern of adult emergence with reference to the azuki bean weevil,Callosobruchus chinensis

Summary The effect of competition pressure on the sequential pattern of adult emergence was studied by using the experimental population of the azuki bean weevil. The density and pattern of emergence curves of the parental adult induced the changes in the shape of emergence curve of the progeny as well as the number of progeny individuals. In order to explain these changes, a simple mathematical model which has two independent variables, the population density and the capacity of environment, was introduced. The model generated basically similar patterns of emergene curves as observed in the present experiments. This means that the model displayed well the competition pressure which differentially acted upon early-born and late-born individuals in the populations being at different densities and which were differentially received by individual progeny according to the sequential distributions of parents. This different severity of competition pressure resulted in the difference of time when the pressure compelled influences on the sequential distribution of adult emergence. Therefore, early developed individuals may have good chance to survive, but the competition pressure works as a factor modifying their fundamental superiority, especially in the scramble type of competition. Intense crowding of the azuki bean weevil gave rise to the scramble type of competition in the relation between the numbers of adults emerged in two successive generations. When parental emergence concentrated in a short term and at high density, the competition becomes intense, resulting in the inferiority of early developed individuals, in the decrease in number at the next generation and in the increase of duration for emergence.     

Methods for estimating the number of the Cryptomeria red mite,especially with the removal by solutions

We compared the removal by solution, the represented count-area method and the beating, for the purpose of estimating the number of the Cryptomeria red mite. Among them the solution procedure provided the smallest standard error as per cent of the mean. 0.25 per cent unheated solution of sodium hydroxide is used for the summer generation, and also 0.25 per cent boiling one for the winter eggs. The mean proportion removed±standard error for the summer eggs and the winter eggs were 0.8770±0.0316 and 0.7920±0.0281 respectively, while 0.9894±0.0050 for the mites.     

Development of the bitterling,Paracheilognathus himantegus (Cyprinidae), with a note on minute tubercles on the skin surface

The development of the eggs and larvae and minute tubercles on the skin surface ofParacheilognathus himantegus larvae were observed. The egg began to hatch approximately 68 hours after insemination and the larvae reached the free-swimming stage 23 days after hatching at water temperature of 22±1°C. The larval development and minute tubercles on the skin surface of this species were similar to those ofAcheilognathus lanceolata, A. limbata, A. signifer andTanakia tanago. However, the shape of the ripe eggs ofP. himantegus differed from those of the four species. As regards the shape of eggs, there was a common characteristic amongP. himantegus, Rhodeus uyekii andA. limbata from Korea. As regards larval development,P. himantegus had two characters also found inRhodeus. These facts seem to suggest thatP. himantegus is closely related toA. lanceolata, A. limbata, A. signifer andT. tanago but is more specialized than these four species, except forA. limbata from Korea.     

Regulation of Histamine Turnover via Muscarinic and Nicotinic Receptors in the Brain

To clarify the regulation of central histaminergic (HAergic) activity by cholinergic receptors, the effects of drugs that stimulate the cholinergic system on brain histamine (HA) turnover were examined, in vivo, in mice and rats. The HA turnover was estimated from the accumulation of tele-methylhistamine (t-MH) during the 90-min period after administration of pargyline (65 mg/kg, i.p.). In the whole brain of mice, oxotremorine, at doses higher than 0.05 mg/kg, s.c., significantly inhibited the HA turnover, this effect being completely antagonized by atropine but not by methylatropine. A large dose of nicotine (10 mg/kg, s.c.) also significantly inhibited the HA turnover. This inhibitory effect was antagonized by mecamylamine but not by atropine or hexamethonium. A cholinesterase inhibitor, physostigmine, at doses higher than 0.1 mg/kg, s.c., significantly inhibited the HA turnover. This effect was antagonized by atropine but not at all by mecamylamine. None of these cholinergic antagonists used affected the steady-state t-MH level or HA turnover by themselves. In the rat brain, physostigmine (0.1 and 0.3 mg/kg, s.c.) also decreased the HA turnover. This inhibitory effect of physostigmine was especially marked in the striatum and cerebral cortex where muscarinic receptors are present in high density. Oxotremorine (0.2 mg/kg, s.c.) and nicotine (1 mg/kg, s.c.) also decreased the HA turnover in the rat brain. However, these effects showed no marked regional differences. These results suggest that the stimulation of central muscarinic receptors potently inhibits the HAergic activity in the brain and that strong stimulation of central nicotinic receptors can also induce a similar effect.     

Arg74 in HLA-DRBI and DRB3 controls a DR3-related epitope

TR81 is a specificity closely related to or identical with DR3. In Caucasoids two amino acids, Tyr at position 26 and Arg at position 74 of HLA class II DR chains, have been found to be associated with the presence of TR81. Recently, a variant of DRBI *03 identified in American Blacks has been shown to possess Arg at position 74 but Phe at position 26. This codon combination is found to be present in four other cell lines where it still specifies the TR81 determinant. This suggests that the TR81 specificity is uniquely dependent on the presence of Arg at position 74.     

Carbachol-Induced Cosecretion of Immunoreactive Atrial Natriuretic Peptides with Catecholamines from Cultured Bovine Adrenal Medullary Cells

The distribution and secretion of atrial natriuretic peptides (ANPs) were investigated in bovine adrenal medulla. (1) Cultured bovine adrenal medullary cells (2 x 10(6)/dish) contained 100.4 +/- 6.0 fmol of immunoreactive ANP (IR-ANP) and 207.3 +/- 6.6 nmol of catecholamines as epinephrine plus norepinephrine. (2) Stimulation of nicotinic but not muscarinic acetylcholine receptors caused a cosecretion of IR-ANP and catecholamines corresponding to the ratio of IR-ANP to catecholamines in cultured bovine adrenal medullary cells. (3) Carbachol-stimulated secretion of IR-ANP was dependent on the presence of extracellular Ca2+. (4) Chromaffin granules isolated from bovine adrenal medulla contained large amounts of IR-ANP and catecholamines, in the same ratio as did cultured adrenal medullary cells. (5) Reverse-phase HPLC analysis showed that both stored and secreted IR-ANP consisted of two components, which eluted at the position of ANP(99-126) or ANP(1-126). These results indicate that ANPs are stored as ANP(99-126) and ANP(1-126) in chromaffin granules, and are cosecreted in parallel with catecholamines in a Ca2+-dependent manner by the stimulation of nicotinic acetylcholine receptors.     

Growth of the malignant and nonmalignant human squamous cells in a protein-free defined medium

Summary A novel protein-free synthetic medium has been developed for the culture of human squamous cell carcinoma cells. This medium, designated PF86-1, supports the serial subcultivation of six out of nine human squamous cell carcinoma cell lines in a protein-free, chemically defined condition without the adapting culture from serum-containing conditions. These cell lines growing in PF86-1 exhibited nearly equal potency to grow in massive culture without noticeable changes in morphology but presented a significantly decreased level of colony forming efficiency when compared with the cells cultured in serum-containing media, suggesting the implication of some autocrine mechanism. Interestingly, this medium supported the growth of normal human squamous cells of oral mucosa and skin for more than 2 mo. in the primary explant culture in spite of high levels of calcium ion concentration, where the overgrowth of fibroblasts as contaminant was not observed. These results suggest that PF86-1 supports the growth of cells derived from epidermal tissues selectively and provides the same defined condition for growth of malignant and nonmalignant human squamous cells. It seems, therefore, that PF86-1 allows investigations on the products of squamous cell carcinoma cells or on the differences of growth mechanisms between normal and neoplastic human squamous cells.     

Dimer Formation of a Cell-Cell Adhesion Protein, gp64 of the Cellular Slime Mold, Polysphondylium pallidum

The cellular slime mold, Polysphondylium pallidum, has two EDTA-resistanttypes of cell-cell adhesion. The major component of them hasbeen identified as a glycoprotein with a molecular mass of 64kDa on SDS-PAGE (referred to as gp64). We found that a substantialamount of the gp64 run as dimer, when gp64 was dissolved inSDS-sample buffer without 2-mercaptoethanol and then subjectedto electrophoresis. The occurrence of a homophilic dimer wasdemonstrated by analyzing the dimer-like band on a gel for itsamino acid sequence and amino acid composition. The dimer-likeband also was analyzed by three sorts of monoclonal antibodies,two of which recognize respectively a conforniational epitopeand a denatured epitope of the protein moiety of gp64. The dataindicate that the native conformation of gp64 is necessary fordimer formation. ²Present address: Institute of Immunological Science, HokkaidoUniversity, Sapporo, 060 Japan     

Micropropagation of horseradish hairy root by means of adventitious shoot primordia

Adventitious shoot primordia were formed on horseradish hairy root cultured in dark. Plantlet formation frequency from the primordia was higher than that from root fragments. Culture for 26 days provided the adventitious shoot primordia, which had the highest potential for plantlet formation (53% explants at 40 days). Benzyladenine supplementation in the dark caused primordium enlargement, but did not increase the number of primordia formed. After adventitious shoot primordia were encapsulated with calcium alginate, kinetin supplementation (2.0–4.0 M) increased the shoot formation frequency (65–80% explants at 20 days) in the light, but also promoted the undesirable formattion of multiple shoots. Supplementation with naphthaleneacetic acid (0.27–5.4 M) in the calcium alginate beads in light enhanced the root emergence from primordia without inhibition of plantlet formation when the encapsulated beads were put on the agar-medium without naphthaleneacetic acid.