Genetics and biology of the sawfly,Athalia rosae (Hymenoptera)

Hymenopteran insects are a unique group of animals in which arrhenotokous reproduction (haploid males develop from unfertilized eggs) is a rule. Males produce sperm through a non-reductional maturation division. A sawfly species,Athalia rosae ruficornis Jakovlev (Tenthredinidae, Symphyta, Hymenoptera), has been introduced as a new experimental material for studies on genetics and developmental biology. Basic features relating to the potential usefulness of the species in elucidating some of the important genetic and developmental biological problems are described.     

Light-induced phase-shifting of the peripheral circadian oscillator in the hearts of food-deprived mice.

In the present study, we investigated the effect of fasting on photoentrainment of the peripheral circadian oscillator in the mammalian heart. Northern blotting showed that a single light pulse applied at an appropriate time in constant darkness, caused obvious phase-shifting in the circadian expression rhythm of the mammalian clock gene Period2 (mPer2) even in the hearts of food-deprived mice. Fasting did not significantly affect either the phase or the light-induced phase-shifts of the mPer2 rhythm. Although several studies of temporal feeding restriction have indicated that feeding is the dominant timing cue for mammalian peripheral oscillators, our findings suggest that feeding is not essential for mammals to induce phase resetting of the circadian oscillator in the heart.     

Expression of hepatic calcium-binding protein regucalcin mRNA is elevated by refeeding of fasted rats: Involvement of glucose,insulin and calcium as stimulating factors

The effect of refeeding on the expression of Ca²⁺-binding protein regucalcin mRNA in the liver of fasted rats was investigated. When rats were fasted overnight, the hepatic regucalcin mRNA level was reduced about 70% of that in feeding rats. Refeeding produced a remarkable elevation of hepatic regucalcin mRNA level (about 150–170% of fasted rats). Liver regucalcin concentration was appreciably increased by refeeding, although it was not altered by fasting. The oral administration of glucose (2 g/kg body weight) to fasted rats caused a significant increase in hepatic regucalcin mRNA level. Moreover, hepatic regucalcin mRNA level was clearly elevated by a single subcutaneous administration of insulin (10 and 100 U/kg) to fasted rats. The hormonal effect was not further enhanced by the simultaneous administration of calcium chloride (250 mg Ca/kg) to fasted rats, although calcium administration stimulated regucalcin mRNA expression in the liver. The present study suggests that the expression of hepatic regucalcin mRNA stimulated by refeeding is significantly involved in the action of insulin and/or calcium as stimulating factors.     

Cloning of cDNA for Vitellogenin of the Parasitoid Wasp, Pimpla nipponica (Hymenoptera: Apocrita: Ichneumonidae): Vitellogenin Primary Structure and Evolutionary Considerations

The cDNA for vitellogenin (Vg) of the parasitoid wasp Pimpla nipponica (Hymenoptera: Apocrita) was cloned and sequenced.¹ The deduced amino acid sequence with 1807 residues was obtained. The N-terminal 20 amino acids chemically determined for vitellin (Vn) agreed completely with the deduced 20 amino acids that follow the 16 amino acid residues for putative signal peptide. The cDNA clone for the Vg of the turnip sawfly Athalia rosae (Hymenoptera: Symphyta), previously obtained and partially sequenced, was also completely sequenced and the amino acid sequence deduced. Amino acid sequences were compared between these two species and also with known Vg sequences from other insects. Common to all these insects is the presence of two long regions with relatively well-conserved amino acid sequences, one near the N-terminal extending 267–282 residues (including two cysteines at conserved locations), and the other starting at position 450 to 655 and extending 279–283 residues, and of a region at the C-terminal extending some 200 residues (about 250 in Aedes aegypti due to the presence of a serine-rich stretch) with 10 cysteines at conserved locations. A molecular phylogenetic tree was constructed.     

UV Irradiation induces an activity which stimulates Simian virus 40 rescue upon cell fusion.

UV irradiation of African green monkey cells greatly stimulated efficiency of simian virus 40 induction from simian virus 40-transformed Syrian hamster cells after cell fusion. The maximum inducing activity was observed at 15 to 20 h after irradiation but remained only transiently. The addition of cycloheximide after UV irradiation eliminated the stimulation of the activity.     

Reexamination of paternal age effect in Down's syndrome

Summary Paternal age distribution for 1279 cases of Down's syndrome born in 1952–1968 was compared with the corresponding distribution for the general population, corrected for the maternal age as well as for the year of birth of the patients. Although there was no difference in the mean paternal age, the two distributions differed significantly, largely due to the excess of fathers aged 55 years and over and to the deficit of those aged 40–44 years in the patients born to mothers aged 30 years and over. The overall pattern of the relative incidence of Down's syndrome with advancing paternal age, with maternal age controlled, seems consistent with the hypothesis proposed by Stene et al. (1977). It increased from 0.8 for fathers aged 20–24 years slowly up to 1.2 for those aged 45–49 years, though with an intermediate drop to 0.8 at the age of 40–44 years, and then sharply to 2.4 for those aged 55 years and over. This rising pattern of the relative incidence with paternal age was essentially the same for the patients born in 1952–1960 and for those born in 1961–1968, although the slope was less steep in the latter than in the former group.This paper is dedicated to Professor Heinrich Schade in honor of his 70th birthday     

Relative potency in acute and chronic suppressive effects of prednisolone and betamethasone on the hypothalamic-pituitary-adrenal axis in man

The relative potency in the hypothalamic-pituitary-adrenal (HPA) suppression of both prednisolone and betamethasone was examined in an acute study with normal volunteers and in a chronic study with glucocorticoid-treated patients. Circadian rhythm of plasma cortisol was studied after a single dose administration of 5 to 30 mg prednisolone or 0.5 to 3.0 mg betamethasone at 8:00 hr. Morning-rise of plasma cortisol occurred on the morning after the administration of 30 mg or less prednisolone but no morning rise was noted after the administration of 1.0 mg or more betamethasone. Plasma ACTH was slightly elevated on the morning after 30 mg prednisolone administration but showed low levels throughout the night after 3.0 mg betamethasone administration. Plasma cortisol responsiveness to ACTH was examined in patients before and during therapy with either prednisolone or betamethasone. The basal cortisol level was not suppressed and the responsiveness to ACTH remained nearly normal during long-term 5 mg prednisolone therapy, but these were completely suppressed during long-term 5 mg betamethasone therapy. The responsiveness to ACTH was nearly normal in patients receiving alternate-day therapy with prednisolone in such large doses as 50 or 60 mg every other day, but was completely suppressed in patients receiving 1.0 mg betamethasone every other day. The relative potency of betamethasone in acute and chronic suppressive effects on the HPA system seems to be much stronger than that of prednisolone in equivalent doses with comparable anti-inflammatory effects. It is also suggested that the alternate-day therapy with such long-acting steroids as betamethasone are useless in preventing HPA suppression.     

Bactericidal effects of macrophages of mice treated with interferon]

The preparations of interferon or virus-inhibiting factor produced in L cell (L-IF) and mouse brain (MB-IF) enhanced the killing of Staphylococcus aureus (S.a.) by the mouse peritoneal macrophage. The L-IF, heat-inactivated at 80 degrees or 60 degrees for 30 min., and mock L-IF could not enhance the killing of S.a. The heterologous human and rabbit interferon preparations didn't enhance the bactericidal activity of macrophage. The L-IF didn't have any effect on the release of lysozyme from the macrophages.     

Oxytocin contracts rat uterine smooth muscle in Ca2(+)-free medium without any phosphorylation of myosin light chain

Contraction of rat uterine smooth muscle related to phosphorylation state of myosin light chain under various conditions was investigated. In the Ca2(+)-containing medium, both high K+ and oxytocin induced marked contraction of the muscle accompanied by pronounced phosphorylation of myosin light chain. In the Ca2(+)-free medium, although both vanadate and oxytocin induced slight contraction, phosphorylation of myosin light chain was only evident for vanadate but not for oxytocin. It was suggested that another mechanism distinct from myosin light chain phosphorylation might be involved in Ca2(+)-independent contraction of uterine smooth muscle elicited by oxytocin.