Effects of the R(+)- and S(-)-isomers of beta-adrenoceptor blockers with intrinsic sympathomimetic activity, befunolol and carteolol, on rabbit intraocular pressure.

Effects of the R(+)- and S(-)-isomers of befunolol and carteolol, beta-adrenoceptors with intrinsic sympathomimetic activity, on the rabbit intraocular pressure were tested. The intraocular pressure was decreased by instillation of the R(+)- and S(-)-isomers of befunolol (0.1 and 0.3%) and of carteolol (1.0%) to the eye and attained the minimum level at 60 min. However, 0.3% of the R(+)- and S(-)-isomers of carteolol did not influence the pressure. The corresponding time courses for the intraocular pressure for the R(+)- and S(-)-isomers did not differ, suggesting that in the treatment of glaucoma, the therapeutic advantage of the R(+)-isomers of befunolol and carteolol may be similar to the S(-)-isomers.     

Selection and reproductive success in males of the dragonfly,Orthetrum japonicum (Odonata: Libellulidae)

Reproductive success, copulation success, and mating success were measured for a population of male dragonflies,Orthetrum japonicum. Copulation success explained the greatest variation in reproductive success. The proportion of copulations followed by oviposition was positively correlated with the number of oviposited eggs per mating. Directional selection on four morphological characters was estimated. The effect of selection on correlated traits was comparable to that of direct selection. Directional selection varied between traits and between episodes in a single trait. The probability that the observed directional selection on the four morphological traits was expected under the condition of the selective neutrality of traits was not smaller than 5%.     

Changes in sensitivity to anoxia of the cardiac action potential plateau during chick embryonic development.

The effects of anoxia on cardiac action potentials were studied at different stages of development of embryonic chick heart. The plateau phase of the action potential was markedly depressed by anoxia in old (15–16 days old) embryonic hearts without any significant change in other configurations of the action potential. Raising the concentration of glucose in the external fluid prevented the shortening of the action potential plateau by anoxia, and, conversely, a further reduction was observed in glucose-free media. In young (3–4 days old) embryonic hearts, the shortening of the action potential plateau was not produced by anoxia, but was produced by a combination of anoxia and glucose deprivation. When the action potential was shortened by anoxia in old hearts and by anoxia plus glucose deprivation in young hearts, isoproterenol (10^?5M), dibutyryl cyclic 3′,5′-adenosine monophosphate (dBcAMP: 1 mM) plus aminophylline (1 mM), and calcium ion (3–6 mM), partially reversed the shortened action potential in old hearts, but did not produce any prolongation in the young hearts. Therefore, the cation channels responsible for the action potential plateau in young hearts may be pharmacologically different from those in old hearts. The differences in action potential plateau between young and old hearts were discussed in relation to dependence upon energy.     

Factors governing the evolution of eusociality through kin selection

The evolution of eusociality through kin selection was analyzed by simple population genetical models. Models were solved analytically with no approximation. The main results are

1. Sex ratio in reproductives in a colony of haplodiploid species does not affect the direction of evolution, contrary to the hypothesis ofTrivers andHare (1976). Female biased sex ratio increases the rate of evolution irrespective of its direction.
2. The only factor that determines the direction of evolution is the balance of benefit and cost of altruism of workers.
3. The value of ratio of benefit to cost of altruism of workers when the change of gene frequency of altruistic allele does not take place is unity in both haplodiploid and diploid species. There is no theoretical reason that the eusociality through kin selection evolves more easily in haplodiploidy than in diploidy, contrary to the hypotheses ofHamilton (1964) andTrivers andHare (1976).
4. The larger the colony size is, the lower the rate of evolution is irrespective of its direction.

It was concluded that discussion on the evolution of altruism which depended on only the values of the degrees of relatedness is misleading. The importance of life history structure, oviposition of workers and number of relating gene(s) in the evolution of eusociality were discussed.     

Efficient production of human tumour necrosis factor in Escherichia coli

Human tumour necrosis factor (TNF) cDNA was isolated from a cDNA library prepared using TNF mRNA from human alveolar macrophages. Using the cDNA, various expression plasmids were constructed and their TNF producibility was examined in Escherichia coli. The best transformants produced a TNF polypeptide in a yield of about 20% of cellular proteins. The purified TNF polypeptide was lacking a methionine residue at the N-terminus, and possessed the expected physical and chemical properties and the biological activities characteristic of TNF.     

Effects of the Consumption of Male Spermatophylax on the Oviposition Schedule of Females in the Decorated Cricket, Gryllodes sigillatus

The effects of the consumption of the spermatophylax produced by males on female fitness were studied in the decorated cricket, Gryllodes sigillatus. An increase in the number of spermatophylaces presented to females did not increase the total number of eggs made by females, the number of eggs laid, or the hatchability of eggs laid by females, but increased the number of eggs laid in the early stage of adult life of females. The duration of the egg stage decreased with the number of spermatophylaces presented to females. The implication of the results on the sham hypothesis that the spermatophylax does not have nutritional value is discussed.     

Cyclic nucleotide PDE-3

Type 3 cyclic nucleotide phosphodiesterase (PDE-3) isoforms exhibit a high affinity (“lowK _m”) for cAMP and are specifically inhibited by cGMP and a number of pharmacological agents, which increase myocardial contractility, inhibit platelet aggregation, and increase smooth muscle relaxation. The PDE-3 family consists of at least two isozymes, PDE-3A (cardiac type) and PDE-3B (adipocyte type), with distinct tissue-specific distributions. PDE-3A mRNA is highly expressed in the cardiovascular system, whereas PDE-3B mRNA is primarily expressed in adipocytes and hepatocytes. Toward understanding potential roles of PDE-3 in diabetes mellitus, we have established a specific and sensitive RNase protection assay (RPA) for quantitating PDE-3A and PDE-3B mRNA in rat diabetic models. In fatty Zucker diabetic (ZDF) rats, PDE-3A mRNA, but not PDE-3B mRNA, was expressed in heart, whereas liver and white and brown fat tissues predominantly expressed PDE-3B mRNA. Unexpectedly, PDE-3B mRNA expression was ≈2.5 times higher than PDE-3A mRNA in aorta from both ZDF and Sprague-Dawley (SD) rats. In contrast, expression levels of PDE-3A mRNA in heart were similar in both species. With this RPA, we were thus able to compare PDE-3A and-3B mRNA levels in different tissues as well as in different rat species.     

Dibutyryl cyclic adenosine monophosphate protects mice against tumor necrosis factor-α-induced hepatocyte apoptosis accompanied by increased heat shock protein 70 expression

Liver injury accompanied by apoptosis of hepatocytes was provoked in mice by an intravenous injection of recombinant tumor necrosis factor-α (rTNF-α) (1.0 µg/kg) together with an intraperitoneal injection of D-galactosamine (D-gal) (500 mg/kg). Injection of various doses of dibutyryl cAMP (DBcAMP) protected mice from TNF-α/D-gal-induced liver injury as assessed by serum alanine aminotransferase (ALT) levels, histological examination and DNA fragmentation. DBcAMP significantly enhanced the Hsp70 expression in the hepatocytes of D-gal/TNF-α-injected mice in close correlation with supression of liver injury. DBcAMP induced Hsp70 expression in the hepatocyte in vitro. These results suggest that increase in Hsp70 expression by DBcAMP is involved in protective mechanisms by DBcAMP against TNF-α-induced liver injury in D-gal-sensitized mice.     

Action of endothelin-1 on rat astrocytes through the ETB receptor.

We investigated the effect of ET-1 on the state of rat cerebral astrocytes (AC) differentiation. AC ceased to proliferate and changed into its differentiated state by treatment with dibutyryl cyclic AMP (DBcAMP). The cell growth activity in DBcAMP-treated AC was stimulated by ET-1 in a dose-dependent manner. Over similar dose ranges, ET-1 suppressed the glutamine synthetase activity in DBcAMP-treated AC. The molar potency of ET-1 in this action was at least 3 orders of magnitude higher than that in mitogenic action in AC under the proliferative state previously reported. Northern blot analysis revealed that ETB receptor mRNA level in DBcAMP-treated AC was markedly higher than that in AC untreated with DBcAMP. Consistently, binding studies showed that the Bmax value for [125I]ET-1 in DBcAMP-treated AC was 16 times higher than that in AC untreated with DBcAMP. These results suggest that ET-1 potently induced a retraction of the differentiation state of AC from fully the specialized state and that the high responsiveness of differentiated AC to ET-1 was partly attributed to the high level expression of the ETB receptor.     

A DWARF FORM OF THE SPINNER DOLPHIN (STENELLA LONGIROSTRIS) FROM THAILAND

A very small form of the spinner dolphin has been found to inhabit the Gulf of Thailand. Ten specimens taken incidentally in a local shrimp fishery differ from specimens of this species collected elsewhere in body size and shape, skull size and shape, number of teeth and numbers of thoracic and lumbar vertebrae. Four cranially adult males were 129–137 cm long, well below the ranges for the Indian Ocean, western Pacific, central Pacific, eastern Pacific and Atlantic. The skull is also very small. Tooth counts and vertebral counts average lower than in other series. The color pattern is not significantly different from that of spinner dolphins in the central and western Pacific, Atlantic and Indian Oceans but differs from that of the small eastern spinner of the eastern Pacific. The Gulf of Thailand specimens are morphologically separable from all other specimens, but it is to be expected that when larger samples are available there will be some overlap. The dwarf form may overlap in body and skull size with small spinner dolphins taken incidentally in a gillnet fishery for sharks off northern Australia. The geographic range of the dwarf spinner may be restricted. The size and status of the population and the impact of the shrimp fishery are unknown and should be investigated. The dwarf spinner may have an ecology different from that of other spinners, feeding mainly on reef-associated and benthic organisms rather than mesopelagic animals.