Phylogeography of the leaf beetle Chrysolina virgata in wetlands of Japan inferred from the distribution of mitochondrial haplotypes

The genetic differentiation among populations of the leaf beetle Chrysolina virgata living in wetlands of Japan was studied based on the sequence data of the mitochondrial cytochrome oxidase subunit I gene region (750 bp). Two distinct lineages of mitochondrial haplotypes were found: one (clade A) consisted of 26 haplotypes distributed over the distribution range of C. virgata between north‐east Honshu and Kyushu, whereas the other (clade B) was monotypic and confined to a small region in north‐east Honshu where it coexisted with clade A. Nested clade analysis for these haplotypes suggested that range expansion and following differentiation due to isolation by distance might have resulted in the present distribution pattern of the haplotypes in clade A. We discuss the evolutionary process leading to the occurrence of two distinct haplotype clades in Japan in terms of repeated colonization from the continent and range expansion and contraction during climatic changes.     

Endothelin inhibits presynaptic adrenergic neurotransmission in rat mesenteric artery

The effect of endothelin(ET) on adrenergic neurotransmission was examined in isolated perfused rat mesenteric arteries. Porcine ET(10(-12) to 10(-10)M) attenuated the pressor response to sympathetic nerve stimulation (NS). It also stimulated the release of prostaglandin E2 (PGE2), but its inhibition of the pressor response to NS was not affected by indomethacin treatment. ET also caused dose-dependent inhibition of [3H]norepinephrine release during NS. Higher doses of ET rather enhanced the pressor response to NS. These results suggest that ET inhibits presynaptic adrenergic neurotransmission without mediation of PGE2, while it potentiates the responsiveness of the postsynaptic alpha-adrenergic receptor. Thus ET appears to act directly on the neuroeffector junction as well as on the peripheral vasculature.     

Regional excitatory and inhibitory amino acid levels in epileptic El mouse brain

Inbred mutant El mice are highly susceptible to convulsive seizures upon tossing stimulation. The levels of excitatory (e.g. glutamate and aspartate) and inhibitory amino acids [e.g. -aminobutyrate (GABA)] were examined in discrete regions of stimulated El mice [El(+)] non-stimulated El mice [El(-)] and ddY mice, which do not have convulsive disposition. In comparison with ddY, a general increased levels of aspartate, glutamate, glutamine, and taurine were detected in brain regions of El(-). The levels of GABA and glycine were almost the same in ddY and El(-). Compared to El(+), the levels of aspartate, glutamate, glutamine, and GABA in El(-) were either the same or higher. In the case of taurine and glycine, the levels in El(-) were either the same or lower than El(+). Alanine is special in that El(-) have a higher level than El(+) in hippocampus but lower in cerebellum. Furthermore, while marked changes were registered in several brain regions, none of the amino acids investigated showed any significant differences in the hypothalamus of three different groups of mice.     

Peri-operative immunotherapy with OK-432

Pre- and postoperative intradermal administration of OK-432 enhanced the SU-PS skin reaction in patients with gastric cancer, but failed to prevent a fall in the NK activity induced by the operation.The change in NK activity was not associated with a change in the proportion of Leu 7-positive cells, but was related to Leu 11a-positive cells. Intradermal injection of OK-432 increased the proportion of Leu 7-positive cells in the patients in whom they accounted for less than 20% of lymphocyte population. The case was the same with Leu 11a-positive cells.Intravenous injection of OK-432 tended to increase suppressor-inducer T cells (CD4⁺2HA⁺ cells), B cells and Leu 7-positive cells. Particularly, the proportions of OK-M₁-positive cells and MHC class II antigen-positive cells increased in all patients. Immunotherapy with OK-432 given intravenously at a dose of 0.1 KE appeared to be safe because no side effects were essentially observed.     

Genetic organization and nucleotide sequence of the stability locus of IncFII plasmid NR1

The stability (stb) locus of IncFII plasmid NR1 was mapped to a 1700 base-pair NaeI-TaqI restriction fragment. A series of unstable plasmids that contained insertion, deletion, and point mutations that inactivated the stability function was isolated. The unstable point mutants examined were all stabilized (complemented) in trans by a copy of the wild-type stb locus, suggesting that the mutations had inactivated diffusible gene products. The nucleotide sequence of the stb locus contained two tandem open reading frames, designated stbA and stbB, that encoded essential trans-acting protein products with predicted sizes of 36,000 Mr and 13,000 Mr, respectively. A third open reading frame, stbC, that could encode a peptide of 8000 Mr was contained within stbB in the complementary DNA strand. Plasmid-encoded proteins of 36,000 Mr and 13,000 Mr were identified in minicell experiments as the products of stbA and stbB, respectively. Unstable deletion mutants that retained the promoter proximal region of the stb locus upstream from stbA but had deleted both stbA and stbB were stabilized in trans by plasmids that could supply StbA and StbB. In contrast, deletion mutants that had lost the stbAB promoter region were not complemented in trans, indicating that this region contained an essential cis-acting site (or sites). Unlike some other loci that mediate stable plasmid inheritance, cloned copies of the wild-type stb locus of NR1 did not exert strong incompatibility (i.e. trans destabilization) against other stb+ derivatives of plasmid NR1 present in the same cell.     

Reassessment of plasma angiotensins measurement: effects of protease inhibitors and sample handling procedures.

Characterization of C- and N-terminal forms of angiotensin (Ang) peptides mandated assessment of methods to determine plasma levels. 125I-Ang I, 125I-Ang II, and 125I-Ang(1-7) were added to blood samples in the presence of protease inhibitors. Ethylenediaminetetraacetic acid (EDTA) inhibited the conversion of 125I-Ang I to 125I-Ang II. o-Phenanthroline and EDTA (EDTA + o-Ph) did not eliminate [des-Asp1] fragments or 125I-Ang(1-7). The combination of EDTA + o-Ph and pepstatin A or 4-(chloromercuri) benzoic acid (PCMB) significantly reduced 125I-Ang(1-7) generation. Only PCMB plus EDTA + o-Ph eliminated [des-Asp1] fragments. Authentic plasma values of Ang peptides require the correct choice of protease inhibitors.     

A novel action of activin A: stimulation of insulin secretion in rat pancreatic islets

The present study was conducted to examine an action of activin A on insulin secretion from rat pancreatic islets. In a batch incubation system, activin A stimulated insulin secretion in a dose-dependent manner at concentrations higher than 1 nM. Furthermore, activin A greatly potentiated glucose-induced insulin release. When islets were perifused with 1 nM activin A, insulin secretion was barely affected in this system. However, the insulin response to 16.7 mM glucose was greatly enhanced. Both the first and second phases of insulin response were enhanced by 1 nM activin A. These results indicate that, in addition to its known actions on pituitary-gonadal and hematopoietic systems, activin A modulates the function of pancreatic islets and stimulates insulin secretion.     

Effect of captopril on renal vascular resistance, renin, prostaglandins and kinin in the isolated perfused kidney

Vasodilatory and natriuretic effects of captopril were studied in the isolated hog kidney perfused with modified Krebs-Ringer solution. Renal arterial infusion of captopril caused increases in releases of renin, prostaglandins (PGE2, 6-keto-PGF1 alpha and PGF2 alpha) and kinin, and was accompanied by a decrease in the renal vascular resistance and an increase in urinary sodium excretion. Indomethacin administered with captopril diminished the saluretic effect of captopril and evoked an increase in kinin, but was associated with a marked decrease in prostaglandin and renin releases, while renal vascular resistance remained decreased. Indomethacin alone did not alter vascular resistance and kinin; however, renin and prostaglandin releases were decreased. Aprotinin administered with captopril showed a decrease in releases of prostaglandins, renin and kinin without any change in vascular resistance. These results suggest that increased release of kinin induced by captopril contributes to a reduction in renal vascular resistance. Increased prostaglandin release after captopril administration may be caused by an increase in kinin without direct involvement of captopril in prostaglandin synthesis. Renal prostaglandins may enhance sodium excretion and mediate renin secretion in captopril perfusion.     

The existence of activin A/erythroid differentiation factor and its inhibitor in human serum: comparison of normal and chronic renal failure sera.

Activin A/EDF, initially found as a differentiation inducer of murine Friend erythroleukemia, also has a stimulatory effect on erythropoiesis in vitro and in vivo. Here we proved activin A/EDF activity in human serum. The activin A/EDF level in 18 normal human serum samples was measured by a specific bioassay and was found to be 8.3 +/- 4.6 ng/ml, indicating that there exists sufficient activity to affect erythropoiesis in normal serum. In contrast, activin A/EDF activity was reduced in the chronic renal failure patients and 23/26 serum samples examined showed levels below 1.2 ng/ml. Further analysis using HPLC revealed that chronic renal failure serum actually contained as much activin A/EDF as normal serum, and that the difference between normal and patient serum existed in the content of a specific inhibitor of activin A/EDF. This observation suggests the possibility that the inhibitor is participating in the regulation of activin A/EDF activity in vivo in chronic renal failure patients and also the possibility of activin A/EDF could be utilized in the therapy of the anemia of such patients.     

Concentrations of essential elements after repeated administrations of tin and selenium

To study effects of simultaneous administration of tin (Sn) and selenium (Se) on concentrations of several essential elements, mice were injected with either SnCl2 (ip) or Na2SeO3 (sc), alone or both compounds at a daily dose of 5 mumol/kg each for 12 consecutive days. Mice were sacrificed at 20 h after the last injection and concentrations of Sn, Se, Na, Ca, Zn, P, Fe, K, and Mg in the liver, kidney, spleen, pancreas, testis, seminal vesicle, lung, femoral muscle, and femoral bone were determined. In the control mice, Sn and Se concentrations were the highest in bone (0.69 micrograms Sn and 6.93 micrograms Se/g dry wt). Administered Sn was found to accumulate in all organs except the testis. Among the essential elements determined, Na was the most affected in terms of concentration in the organs and Mg was the least affected element in these organs. Among the organs tested, each elemental concentration in the pancreas was most affected. Simultaneous injections of Sn and Se appeared to keep the correlation coefficients between elements similar to those found in the control mice.