Effect of serotonin on ouabain-sensitive, K+-dependent, p-nitrophenylphosphatase activity in strial marginal cells of normal and reserpinized guinea pigs

Na+,K+-ATPase activity is abundant on the basolateral infoldings of the strial marginal cells and contributes to the maintenance of the characteristic electrolyte composition of the endolymph. However, the stria vascularis of the cochlea is known not to be innervated. In order to clarify its humoral regulation by serotonin, the K+-p-nitrophenylphosphatase activity of strial marginal cells was investigated with a cerium-based method in normal guinea pigs and in guinea pigs treated with reserpine, 5-hydroxytryptamine or reserpine plus 5-hydroxytryptamine. K+-p-nitrophenylphosphatase activity was almost completely depressed 3--20 days after reserpine administration. Ten days after reserpinization, followed by repeated 5-hydroxytryptamine treatment, the enzyme activity was detectable. These results suggest that 5-hydroxytryptamine increases the phosphatase activity. Thus, the function of the stria vascularis in producing cochlear endolymph may be regulated by 5-hydroxytrypt amine. © 1998 Chapman & Hall     

PHYSIOLOGICAL ACTIVITIES OF HELMINTHOSPOROL AND HELMINTHOSPORIC ACID: I. EFFECTS ON GROWTH OF INTACT PLANTS

Helminthosporol (H-ol) and helminthosporic acid (H-acid) wereeffective in promoting elongation of leaf sheaths of rice, Japanesebarnyard grass and dwarf maize (d-2 and d-5) and of hypocotylsof taisai (Brassica chinensis), but inactive in leaf sheathsof oat and wheat, hypocotyls of sesame and morning glory (Pharbitisnil) and epicotyls of Pharbitis and dwarf and tall peas. Onthe elongation of the leaf sheath of maize d-1, H-ol was promotivebut the activity of H-acid was doubtful. On hypocotyls of lettuceand daikon (Raphanus sativus), only H-acid was active. Multiplicationrate and size of fronds of Lemna perpusila were not affectedby either of the substances. Compared with gibberellic acid for the effect on the shoot growth,H-ol and H-acid were weak in activity and narrower in the scopeof plants that responded. H-ol and H-acid characteristicallypromoted the elongation of the primary root. Comparative effectivenessof H-ol and H-acid varied with plant species or parts examined. ¹ This study was supported in part by grant-in aid of the Ministryof Education (No. 0417). The results reported here were presentedat the Annual Meeting of the Botanical Society of Japan at Kanazawain 1964 (S).     

Morpho-Physiological Study of Ameboid Movement. 3. Invisible gel structures in the endoplasm of an ameba of the verrucosa type

SYNOPSIS. A small ameba of the verrucosa type has a flattened and fan-shaped body, at the broadest front of which there is formed a distinct hyaline zone. Along the lateral borders thereof there is a thin optically indistinct but rigid body wall, which can be determined by means of cine-micrographic analysis of the positions of granules in and near it, and their movements. Its caudal portion is well differentiated from the rest of the body and was identified as a region of complicated conditions, manifesting solating activity, contractility, ejection, formation of caudal pseudopods, and continuous shifting of its minute components. The tracks of moving endoplasmic granules were plotted to determine their individual irregularities in velocity and direction of movement. These tracks suggest the existence in the endoplasm of small to large motionless gel structures derived from the frontal hyaline zone, which is therefore postulated to be heterogeneously gelate as a whole. Judging from the fact that granules carried by the protoplasmic matrix passed through these so-called gel areas, it is proposed that the source of the motive force of ameboid movement may be in the advancing edge of the clear frontal zone where gelation is vigorously taking place.     

The lack of chiral specificity in a termite queen pheromone

The queens of many social insects produce pheromones that influence the behaviour and physiology of colony members. Pheromones produced by queens have long been considered as the prime factor inhibiting the differentiation of new reproductive individuals. A volatile pheromone consisting of a blend of n‐butyl‐n‐butyrate and 2‐methyl‐1‐butanol comprises a queen pheromone that inhibits the differentiation of female neotenic reproductives (secondary queens) of a termite Reticulitermes speratus. 2‐Methyl‐1‐butanol is the first chiral molecule to be identified as a primer pheromone in social insects, which presents the intriguing question of whether enantiomeric composition plays a role in caste regulation. In the present study, we report that the (R)‐ and (S)‐enantiomers and the racemic mixture of 2‐methyl‐1‐butanol show significant inhibitory effects on the differentiation of new female neotenics in combination with n‐butyl‐n‐butyrate, whereas no significant difference in inhibitory activity is observed among them. These results suggests that termites recognize 2‐methyl‐1‐butanol as a queen signal but they do not distinguish between the stereostructures of the enantiomers.     

Morphology and biology of Polysaccus japonicus (Crustacea, Rhizocephala, Akentrogonida, Polysaccidae, fam. n.), a parasite of the ghost-shrimp Callianassa japonica

The morphology and biology of Polysaccus japonicus Høeg & Lützen, 1993 is described. Nearly all infected hosts are adults, the females of which become castrated. Each bears 4–50 (female) externae on the underside of the abdomen. The externae are interconnected via a root system within the host's perineural blood sinus. The externae pass through three moults. Cypris larvae inject spermatogonia into the immature externa's mantle cavity, which is where spermiogenesis occurs later. Multiplication of the male cells is probably supported by secretion from paired mantle cavity glands, presumably homologous to the receptacles of kentrogonid rhizocephalans. Late during the 2nd intermoult the visceral mass ruptures to release the ova into the mantle cavity where they become fertilized. The third moult results in opening of the mantle aperture which initiates a period of vigorous peristalsis of the muscular mantle. Following emission of the cypris larvae the externae perish leaving distinct scars. The root system always contains buds of various sizes and stage of development. When the scarred host moults, the most advanced buds emerge to give rise to a new generation of externae. This is thought to be repeated for the rest of the host's life.
The antennule of the cyprid has a relatively very long and slender 3rd segment, a unique construction among Akentrogonida. Because of this and the presence of special mantle cavity glands, a new family, Polysaccidae, is erected, which in some characters is intermediate between the Kentrogonida and the Akentrogonida.