| a novel mechanism of sperm motility in a viscous environment: corkscrew-shaped spermatozoa cruise by spinning. | fertilization of the green tree frog, rhacophorus arboreus, occurs in the viscous environment of a foam nest, which is laid on vegetation. their spermatozoa have a characteristic corkscrew-shaped head and a thick tail that extends perpendicularly to its longitudinal axis. however, it is unclear how these corkscrew-shaped spermatozoa move in this highly viscous environment. here, we found that the spinning of the corkscrew-shaped head, caused by winding and unwinding of the tail, enables the sper ... | 2009 | 19334064 |
| ultrastructural analysis of spermiogenesis in rhacophorus arboreus (amphibia, anura, rhacophoridae). | the spermatozoa of the japanese green tree frog, rhacophorus arboreus (amphibia, anura, rhacophoridae), have a characteristic corkscrew-shaped head and a thick tail that extends perpendicular to the longitudinal axis of the head. we examined the process of spermatogenesis in rh. arboreus, particularly spermiogenesis, using light and transmission electron microscopy. spermiogenesis was categorized into the early, mid, and late stages based on the spermatid morphology and their location within the ... | 2011 | 21780156 |
| a novel cysteine knot protein for enhancing sperm motility that might facilitate the evolution of internal fertilization in amphibians. | internal fertilization ensures successful reproduction of tetrapod vertebrates on land, although how this mode of reproduction evolved is unknown. here, we identified a novel gene encoding sperm motility-initiating substance (smis), a key protein for the internal fertilization of the urodele cynops pyrrhogaster by edman degradation of an isolated protein and subsequent reverse transcription polymerase chain reaction. the smis gene encoded a 150 amino-acid sequence including the cysteine knot (ck ... | 2016 | 27579691 |
| the fine structure of the spermatozoa of two species of rhacophorus (arboreus, schlegelii). i. phase-contrast microscope, scanning electron microscope, and cytochemical observations of the head piece. | green tree frogs, rhacophorus arboreus and rhacophorus schlegelii, living on the main island of japan have spermatozoa in the form of a counterclockwise corkscrew composed of about 20 coils arranged in the shape of a cone. a head piece coiled loosely and tightly 5-6 times each. it was composed of two subcoils, one outside and the other inside. the outside subcoils composed the nuclear head, and the inside coils the acrosome. following the head piece, a middle piece which had a mitochondrial shea ... | 2006 | 2445866 |
| origin of somatic cells and histogenesis in the primordial gonad of the japanese tree frog rhacophorus arboreus. | gonadal development in rhacophorus arboreus, a sexually semidifferentiated type of tree frog, was observed by means of the electron microscope, and cell proliferation kinetics were examined autoradiographically. the genital ridge consisted of coelomic epithelial cells and primordial germ cells. the gonadal medulla was formed by the segregation of epithelial cells within the primordial gonad. thereafter, the medullary cell mass was well developed and oogenesis began in the gonadal cortex, irrespe ... | 1989 | 2802180 |
| [1st year gonadal development in the frog, rhacophorus arboreus]. | | 1969 | 5389076 |
| the protective effects of some narcotic substances against x-irradiation on aquatic animals. (3). effects of urethane and changes in concentration of chlorobuthanol solution against x-irradiation in larvae of rhacophorus arboreus. | | 1966 | 5232396 |
| the protective effects of some narcotic substances against x-irradiation in aquatic animals. (i). effects of chlorobutanol in larvae of rhacophorus arboreus. | | 1966 | 5232394 |
| mycobacterium marinum infection in japanese forest green tree frogs (rhacophorus arboreus). | four japanese forest green tree frogs (rhacophorus arboreus) were presented with emaciation, abdominal distention and ulcerative and nodular cutaneous lesions affecting the brisket, limbs, digits and ventral abdomen. another three frogs had been found dead in the same tank 1 year previously. necropsy examination of these seven frogs revealed splenomegaly and hepatomegaly, with multiple tan-yellow nodular foci present in the liver, spleen, heart, lungs, ovaries and kidneys. microscopically, five ... | 2014 | 25047922 |
| redescription of gyrinicola japonica, a tadpole-endoparasitic nematode from japan, with resurrection of the family gyrinicolidae (nematoda: oxyurina). | the taxonomic account of the tadpole-parasitic nematode gyrinicola japonica yamaguti, 1938, which is the type species of the genus, was reassessed based on syntypes and newly-collected specimens from the type locality. our redescription of g. japonica addresses the erroneous original description of a spicule in this nematode, and emends the diagnosis of the species. additionally, molecular phylogenetic trees based on nuclear 18s and 28s rdna sequences revealed that g. japonica forms a distinctiv ... | 2020 | 32068376 |