Initiation and solicitation in male-female grooming in a wild Japanese macaque troop on yakushima island

Grooming initiation among adult males and females of a Japanese macaque troop was analyzed during the non-mating season. Some gestures (“solicitation”) elicited grooming from partners at a high rate. Grooming initiation patterns were divided into two main types: (1) a male often solicited a female to groom him immediately after approaching her and was groomed by her; and (2) a female approached an alpha male selectively, and immediately groomed him. After a female groomed a male, she rarely solicited him to groom her and instead often moved away from him. These results indicated that males were motivated to be groomed, while females were more highly motivated to groom. Sex differences in grooming motivation can be explained by sex differences in the benefit to be groomed.     

Selective inhibition of MAO-A in serotonergic synaptosomes by two amphetamine metabolites, p-hydroxyamphetamine and p-hydroxynorephedrine

The present study was carried out mainly to clarify whether the two amphetamine metabolites, p-hydroxyamphetamine (P-OHA) and p-hydroxynorephedrine (p-OHN) are taken up by mouse brain 5-hydroxytryptamine (5-HT) nerve terminals to inhibit type A monoamine oxidase (MAO-A) and then potentiate the abnormal behavior, head-twitch. Of the two metabolites, only intracerebroventricular p-OHA, at 80 μg/mouse, sufficient to cause a head-twitch response (HTR), appreciably inhibited MAO-A activity without affecting MAO-B activity in homogenates of the mouse striatum, hypothalamus and the rest of the forebrain; and p-OHN did not inhibit either type of MAO at the dose tested. Estimation of intra- and extrasynaptosomal MAO-A activity showed that both metabolites significantly inhibited only the intrasynaptosomal deamination of 5-HT by MAO-A with p-OHA being more potent. Taken together with our previous findings, these present results clearly indicate that p-OHA may accumulate in the 5-HT nerve terminals through the uptake system, and concomitantly inhibit MAO-A activity. These actions of p-OHA may increase intraneuronal 5-HT levels and then potentiate 5-HT release to cause interaction with the post-synaptic 5-HT receptors.     

Termination of endothelin signaling: Role of nitric oxide

Cellular mechanisms responsible for the termination of ET-1 signal are poorly understood. In order to examine the hypothesis that nitric oxide serves as a physiological brake of ET- 1 signaling, Chinese hamster ovary (CHO) cells stably transfected with the ET_A receptor cDNA (CHO-ET) were studied. CHO-ET responded to ET-1 with robust [Ca²⁺], transients and developed a long-lasting homologous desensitization. Donors of nitric oxide (NO), 3-morpholino-sydnonimine HCl(SIN-1), or sodium nitroprusside (SNP) reduced the amplitude of these responses, accelerated the rate of [Ca²⁺], recovery, and counteracted the development of homologous desensitization by a cyclic GMP-independent mechanism, suggesting an alternative mode for NO modulation of ET-1 responses. Stimulation of CHO-ET cells with mastoparan, a wasp venom acting directly on G proteins (bypassing receptor activation), was inhibited by NO, revealing a postreceptoral target for NO-induced modulation of [Ca²⁺] mobilization. Using a lys⁹-biotinylated ET-1 (ET-1 [BtK⁹]), binding sites were “mapped” in CHO-ET cells. Receptor-ligand complexes did not exhibit spontaneous dissociation during 60min observations. Quantitative fluorescence microscopy revealed that SNP or SIN-1 caused a rapid, concentration-dependent, and reversible dissociation of biotinylated ET- 1 from ET_A receptor (EC₅₀ = 75 μM and 6 μM, respectively), an effect that was not mimicked by 8-bromo-cyclic GMP. “Sandwich” co-culture of endothelial cells with CHO-ET showed that activation of NO production by endothelial cells similarly resulted in dissociation of ET-1 [BtK⁹] from ET_A receptors. We hypothesize that NO plays a role in physiological termination of ET-1 signalling by dual mechanisms: (1) displacement of bound ET-1 from its receptor, thus preventing homologous desensitization, and (2) interference with the postreceptoral pathway for [Ca²⁺] mobilization, hence inhibiting end-responses to ET-1. © 1994 Wiley-Liss, Inc.     

Pyridoxal kinase immunoreactivity in rabbit brain

Murine polyclonal antibody against purified bovine brain pyridoxal kinase (EC 2.7.1.35) was generated and showed cross-reactivity with rabbit brain pyridoxal kinase. This antibody was used to immunohistochemically examine the distribution of pyridoxal kinase in the rabbit brain. The cytoplasm of neuronal cells and neuroglial cells in the cerebral cortex, hippocampal region, brain nuclei and cerebellar cortex showed positive staining with various degrees of intensity. The neuronal cells and surrounding fibers in some brain nuclei, such as the area tegmentalis ventralis or the substantia nigra, showed intense staining. The neuronal cells of the hippocampal region showed somewhat weak reactivity, but some with intense reactivity were found sparsely distributed and positive staining fiber networks of a very low density were also observed.     

Osteological and histological comparison of the development of the interphalangeal intercalary skeletal element between hyloid and ranoid anurans

Some frog species have a unique skeletal element, referred to as the intercalary element (IE), in the joints between the terminal and subterminal phalanges of all digits. IEs are composed of cartilage or connective tissue and have a markedly differ shape than the phalanges. IEs are highly related to the arboreal lifestyle and toe pads. The IE is found only in neobatrachian frogs among anurans, suggesting that it is a novelty of Neobatrachia. IEs are widely distributed among multiple neobatrachian lineages and are found in the suborders Hyloides and Ranoides (the two major clades in Neobatrachia). However, it is unclear whether the IEs found in multiple linages resulted from convergent evolution. Therefore, in this study, we aimed to examine how similar or different the developmental trajectories of the IEs are between Hyloides and Ranoides. To that end, we compared the osteological and histological developmental processes of the IEs of the hyloid frog Dryophytes japonicus and the ranoid frog Zhangixalus schlegelii. Both species shared the same IE-initiation site and level of tissue differentiation around the IE when it began to form in tadpoles, although the IE developments initiated at different stages which were determined by external criteria. These results suggest that similar mechanisms drive IE formation in the digits of both species, supporting the hypothesis that the IEs did not evolve convergently.     

Calpain and calpastatin in porcine retina. Identification and action on microtubule-associated proteins.

Two forms of Ca2+-dependent cysteine proteinase (calpain, EC 3.4.22.17) and their specific endogenous inhibitor (calpastatin) were partially purified from porcine retina: calpain I (low-Ca2+-requiring form) was half-maximally activated at 8 microM-Ca2+, and calpain II (high-Ca2+-requiring form) at 250 microM-Ca2+. Both calpain I and calpain II were inhibited by calpastatin. Calpain I from porcine retina was shown to be composed of 83 000- and 29 000-Mr subunits, and calpain II of 80 000- and 29 000-Mr subunits, by the use of monospecific antibodies. Calpains I and II were both found to hydrolyse microtubule-associated proteins 1 and 2 rapidly.     

Phosphoramidon inhibits the generation of endothelin-1 from exogenously applied big endothelin-1 in cultured vascular endothelial cells and smooth muscle cells

When cultured porcine aortic endothelial cells (ECs) were incubated with porcine big endothelin-1 (bit ET-1(1-39)), there was a time-dependent increase in immunoreactive (IR)-ET in the culture supernatant, in addition to an endogenous IR-ET release fron the cells. Reverse-phase HPLC of the culture supernatant revealed one major IR-ET component corresponding to the elution position of synthetic ET-1, thereby indicating that the additional increase in IR-ET was due to the conversion of big ET-1 to mature ET-1(1-21). Phosphoramidon, a metalloproteinase inhibitor, strongly suppressed this increase in IR-ET as well as the endogenous IR-ET release. Cultured vascular smooth muscle cells (VSMCs) also released IR-ET. The apparent conversion of exogenously applied big ET-1 to ET-1 and its inhibition by phosphoramidon were observed using cultured VSMCs, although the enzyme inhibitor did not influence the basal secretion of IR-ET from VSMCs. These results suggest that both cultured ECs and VSMCs can generate ET-1 from exogenously applied big ET-1 via action of the same type of phosphoramidon-sensitive metalloproteinase, which is also involved in the endogenous ET-1 generation in ECs.     

Mechanisms of somatic embryogenesis in cell cultures: Physiology,biochemistry, and molecular biology

Summary One of the most characteristic cell functions in plants is totipotency. Somatic embryogenesis can be regarded as a model system for the investigation of mechanisms of totipotency, because a high frequency and synchronous embryogenic system from single somatic cells has been established in carrot suspension cultures. Four phases are recognized in this process, and several molecular markers, viz. polypeptides, mRNAs, antigens against monoclonal antibodies, can be detected during the expression of totipotency, but they disappear during its loss. Four organ-specific genes have been isolated from hypocotyls and roots by differential screening. They were expressed preferentially after the globular-heart stages of embryogenesis, and were strongly suppressed by auxin. A CEM 1 gene was isolated by differential screening of embryogenic cell clusters. This gene was expressed strongly and transiently during the proglobular and globular stages. The sequence of CEM 1 was found to encode a polypeptide showing high homology to the elongation factor isolated from eucaryotic cells. Thus good progress is being made in understanding the basic mechanisms of somatic embryogenesis. Presented in the Session-in-Depth Developmental Biology of Embryogenesis at the 1991 World Congress on Cell and Tissue Culture, Anaheim, California, June 16–20, 1991.     

Conversion of big endothelin-1 to endothelin-1 by two types of metalloproteinases derived from porcine aortic endothelial cells

Incubation of big endothelin-1 (big ET-1(1-39] with either the cytosolic or membrane fraction obtained from cultured endothelial cells, resulted in an increase in immunoreactive-endothelin (IR-ET), which was markedly inhibited by metal chelators. Phosphoramidon, a metalloproteinase inhibitor, specifically suppressed the membrane fraction-induced increase in IR-ET, whereas the increase in IR-ET observed with the cytosolic fraction was not influenced by phosphoramidon. Reverse-phase (RP)-HPLC of the incubation mixture of big ET-1 with the cytosolic or membrane fraction revealed one major IR-ET component corresponding to the elution position of synthetic ET-1(1-21). Simultaneously, immunoreactivities like the C-terminal fragment (CTF22-39) of big ET-1 were present, as deduced from the RP-HPLC coupled with the radioimmunoassay for CTF. Our results indicate the presence of two types of metalloproteinases, which convert big ET-1 to ET-1 via a single cleavage between Trp21 and Val22, in vascular endothelial cells.