Growth-related changes in color and sex inHalichoeres poecilopterus

Coloration and sex change were studied in a temperate wrasseHalichoeres poecilopterus in the central part of the Seto Inland Sea, Japan. 1,270 examples, 45–179 mm SL, were collected from May to December both in 1983 and 1984. The species is a diandric, protogynous hermaphrodite, and has three color patterns: pale color type (A), brilliant color type (B) and intermediate color type (AB). A-fish were less than 142 mm SL and consisted of primary males (42.6%), females (55.4%), secondary males (0.3%) and fish with transitional gonads (1.7%). A-females changed their color to B, through AB, in the size range 101–131 mm SL. A-primary males changed their color to B, through AB, in the size range 103–134 mm SL. B-fish consisted of primary males (38.6%), secondary males (54.6%) and fish with transitional gonads (6.8%). The majority of females changed their sex to male in the size range 98–131 mm SL.     

Functional morphology of Gené's organ inHaemaphysalis longicornis (Acari: Ixodidae)

The structure and function of Gené's organ, which secretes the egg wax, were investigated inHaemaphysalis longicornis. The hatching rates of eggs deposited before and after the prevention of the eversion of Gené's organ were compared at the conditions of 30°C, 100% RH and soaking in liquid paraffin. The movement of Gené's organ was observed, and the structures of this organ in unfed and ovipositing females were examined with both light and scanning electron microscopes.The hatching rates of eggs without contact with Gené's organ were markedly lower (4.9%) than that of normal eggs (94.5%) even at the suitable condition for eggs (30°C, 100% RH). In contrast, the hatching rates of eggs soaked in liquid paraffin without contact of Gené's organ were considerably higher (71.8%) than that of eggs without both Gené's organ contact and soaking in liquid paraffin.When oviposition commenced, the camerostome of the female was widened by a downswing of the capitulum, the paired horns of Gené's organ emerged through it, and the oviposited egg from the genital aperture was coated with egg wax. At the same time of retraction of the horns which grip an egg, the capitulum was swung up and the egg was loaded on the scutum.Gené's organ included the outer and inner cuticles, and the outer one is highly folded like bellows when the horns of this organ were retracted into the haemocoel. The undeveloped glands lying in the peripheral region of Gené's organ in the unfed stage commenced their enlargement at the time of the onset of feeding, and they became large tubular glands in the 1-day ovipositing female. The columnar glandular cells of the tubular glands extended their domed apical region into the lumen and contained numerous secretory granules during oviposition.These results suggest that the tubular glands secrete the egg wax which is indispensable for egg survival by serving as a waterproofing agent.     

Effects of net charge on the hydrogen-deuterium exchange parameters of lysozyme.

Possible effects of changes in net charge on protein hydrogen exchange rates were investigated by desalting hen egg-white lysozyme, which allowed its net charge to increase with decreasing pH in the acid region. Chloride ion-binding ratios, expressed as ratios of free to total Cl^?, were measured with a chloride-specific electrode at pH 5 on a 2.4% solution of a five-time-desalted product. This ratio was used to show a 97% reduction of the 11% Cl^? present in a commercial lysozyme preparation upon three passes of the enzyme through a column of ion-retardation resin. Net charges on the purified product were assigned from a combination of electrophoretic mobility and proton titration data gathered under minimal ionic strength conditions. The net charge on the desalted product increased by 1.64 units between pH 5.0 and 3.0. Hydrogendeuterium exchange studies on the purified lysozyme in D₂O were obtained using the near-infrared region of a Cary 14R spectrophotometer. The rate-pD profile for k₂, the rate constant for the intermediate class of exchanging hydrogens, showed a decrease in the apparent pD of minimum exchange rate of 0.3 units, when compared to that obtained earlier in 0.2 m added NaCl. However, the rate of exchange at pD minimum and the number of hydrogens in the class remained largely unaffected. A similar shift was observed for the rate-pD profile of the class 1 hydrogens. Thus, the effect of an increase in net positive charge is to shift the rate-pD profile to a lower pD. Moreover, the effect extended to the interior peptide hydrogens of this globular protein. Consequently, the exchange rates of all the observable hydrogens are altered by the net charge changes, and the effect appeared uniform. The shift can be accounted for quantitatively by applying electrostatic interaction terms to the acid and base catalytic constants characterizing the exchange process. The calculated electrostatic interaction factors in minimal salt and 0.2 m added NaCl were found to be 29 and 18% lower, respectively, than those obtained theoretically. Therefore, under conditions where changes in net charge may occur for a globular protein, the effect on hydrogen exchange rates can be estimated fairly well theoretically, especially at moderate ionic strengths.     

Human leukocyte-derived arginine aminopeptidase. The third member of the oxytocinase subfamily of aminopeptidases

In this study we report the cloning and characterization of a novel human aminopeptidase, which we designate leukocyte-derived arginine aminopeptidase (L-RAP). The sequence encodes a 960-amino acid protein with significant homology to placental leucine aminopeptidase and adipocyte-derived leucine aminopeptidase. The predicted L-RAP contains the HEXXH(X)18E zinc-binding motif, which is characteristic of the M1 family of zinc metallopeptidases. Phylogenetic analysis indicates that L-RAP forms a distinct subfamily with placental leucine aminopeptidase and adipocyte-derived leucine aminopeptidase in the M1 family. Immunocytochemical analysis indicates that L-RAP is located in the lumenal side of the endoplasmic reticulum. Among various synthetic substrates tested, L-RAP revealed a preference for arginine, establishing that the enzyme is a novel arginine aminopeptidase with restricted substrate specificity. In addition to natural hormones such as angiotensin III and kallidin, L-RAP cleaved various N-terminal extended precursors to major histocompatibility complex class I-presented antigenic peptides. Like other proteins involved in antigen presentation, L-RAP is induced by interferon-gamma. These results indicate that L-RAP is a novel aminopeptidase that can trim the N-terminal extended precursors to antigenic peptides in the endoplasmic reticulum.     

Theanine,gamma-glutamylethylamide,is metabolized by renal phosphate-independent glutaminase

The distribution of theanine-degrading activity in Wistar rats was examined and this activity was detected only in the kidney. Judging from polyacrylamide gel electrophoresis, theanine-degrading enzyme from rat kidney was purified almost to homogeneity. Theanine-degrading activity was co-purified with glutaminase activity, and the relative activity for theanine was about 85% of that for L-glutamine throughout purification. Substrate specificity of purified enzyme preparation coincided well with the data of phosphate-independent glutaminase [EC 3.5.1.2], which had been previously reported. It was very curious that gamma-glutamyl methyl and ethyl esters were more effectively hydrolyzed than theanine and L-glutamine, in view of relative activity and K(m) value. It was suggested that gamma-glutamyl moiety in theanine molecule was transferred to form gamma-glutamylglycylglycine with relative ease in the presence of glycylglycine. On the other hand, purified phosphate-dependent glutaminase did not show theanine-degrading activity at all. Thus, it was concluded that theanine was hydrolyzed by phosphate-independent glutaminase in kidney and suggested that, as for the metabolic fate of theanine, its glutamyl moiety might be transferred by means of gamma-glutamyl transpeptidase reaction to other peptides in vivo.     

Cloning and characterization of the fur gene from Moraxella bovis

A homologue of the ferric uptake regulator gene (fur) was isolated from Moraxella bovis by degenerate polymerase chain reaction and cloning. Fur protein of M. bovis exhibited 72.1% amino acid identity with Acinetobacter calcoaceticus Fur. Western blot analysis showed a decrease of Fur expression in response to sufficient-iron conditions compared with deficient-iron conditions. An electrophoretic mobility-shift assay indicated that Fur protein binds to DNA fragments containing a putative Fur-box derived from the upstream region of the M. bovis fur gene. Fur of M. bovis may regulate the expression of iron transport systems in response to iron limitation in the environment.     

Inhibiting effects of theanine on caffeine stimulation evaluated by EEG in the rat

In this study, the inhibiting action of theanine on the excitation by caffeine at the concentration regularly associated with drinking tea was investigated using electroencephalography (EEG) in rats. First, the stimulatory action by caffeine i.v. administration at a level higher than 5 micromol/kg (0.970 mg/kg) b.w. was shown by means of brain wave analysis, and this level was suggested as the minimum dose of caffeine as a stimulant. Next, the stimulatory effects of caffeine were inhibited by an i.v. administration of theanine at a level higher than 5 micromol/kg (0.781 mg/kg) b.w., and the results suggested that theanine has an antagonistic effect on caffeine's stimulatory action at an almost equivalent molar concentration. On the other hand, the excitatory effects were shown in the rat i.v. administered 1 and 2 micromol/kg (0.174 and 0.348 mg/kg) b.w. of theanine alone. These results suggested two effects of theanine, depending on its concentration.     

Methamphetamine-induced hyperactivity and behavioral sensitization in PACAP deficient mice

Mice lacking the PACAP gene (PACAP(-/-)) display psychomotor abnormalities such as novelty-induced hyperactivity and jumping behavior, and they show different responses to amphetamine, a typical psychostimulant. The present study examined the possible role of endogenous PACAP in methamphetamine (METH)-induced hyperactivity and behavioral sensitization. The locomotor activity of hyperactive PACAP(-/-) mice was measured using the infrared photocell beam detection system, Acti-Track, after a habituation period. Single administration of METH (1 and 2mg/kg) caused a robust increase in locomotor activity of mice, but this effect did not differ between wild-type and PACAP(-/-) mice. Repeated administration of METH (1mg/kg) for 7 days enhanced METH-induced hyperactivity, and this sensitization was observed even when withdrawn for 7 days. There was no difference in the degree of development and expression of METH-induced behavioral sensitization between wild-type and PACAP(-/-) mice. In addition, there was no difference in METH-induced increases in extracellular serotonin and dopamine levels in the prefrontal cortex of the normal and sensitized mice between the two groups. These results suggest that endogenous PACAP is not involved in the locomotor stimulant activity of acute METH and repeated METH-induced behavioral and neurochemical sensitization.     

Heat-epimerized tea catechins have the same cholesterol-lowering activity as green tea catechins in cholesterol-fed rats

Tea catechins are known to be epimerized by heat treatment. The effect of heat-epimerized tea catechins on serum cholesterol concentration was compared with that of green tea catechins. Our observations strongly suggest that both tea catechins and heat-epimerized tea catechins lower serum cholesterol concentration by inhibiting cholesterol absorption in the intestine. There was no differential effect between the two catechin preparations.