this study presents the first details on morphological and histological characteristics of gonads, gonadal development stages and reproductive index of the persian loach, oxynoemacheilus persa (heckel, 1847), an iranian endemic species. sampling was done from april 2010 to april 2011 using electrofishing device and a total of 196 individuals were collected. the gonads of specimens were removed,...

Gonad morphology at the gross anatomical or histological levels has long been studied by fisheries biologists to identify annual reproductive cycles and length of breeding season, among other goals. Comparative surveys across vertebrate taxa have not been detailed enough, however, to describe fully the differences and similarities among gonads of bony fishes and other vertebrates, and to use go...

The nematode gonad is an exemplary system for the study of organogenesis and fundamental problems in developmental and cellular biology. Nematode gonads vary dramatically across species (Chitwood, B.G., Chitwood, M.B., 1950. Introduction to Nematology." University Park Press, Baltimore; Felix, M.A., Sternberg, P.W., 1996. Symmetry breakage in the development of one-armed gonads in nematodes. De...

Reproductive or neotenic soldiers of the Archotermopsid Zootermopsis nevadensisnevadensis (Hagen) are compared to sterile soldiers and primary male reproductives. Several head capsule morphometrics correlate significantly with gonad size across all forms and both sexes of soldiers. The easily observed field character of ratio of mandible length to labrum length is a consistent and reliable feat...

The pearl oyster, “Pinctada radiate”, is a native species of Persian Gulf area, which has always been attractive for its ability of producing pearl. Thus, studying the gonadal maturation of the pearl oyster has been important for nucleus implantation to pearl production. In this study, samples were taken in winter and spring from Lavan and Kish Islands. The classic histological methods were use...

Like other organs, the C. elegans gonad develops from a simple primordium that must undergo axial patterning to generate correct adult morphology. Proximal/distal (PD) polarity in the C. elegans gonad is established early during gonadogenesis by the somatic gonad precursor cells, Z1 and Z4. Z1 and Z4 each divide asymmetrically to generate one daughter with a proximal fate and one with a distal ...

To culture germline stem cells in vitro, establishment of the cell lines that can be used as the feeder cells is a prerequisite. In this study, we tried to establish gonad-derived cell lines in Siberian sturgeon (Acipenser baerii). Five 1-year-old A. baerii were used as a donor of gonad tissues, and gonad-dissociated cells were cultured in vitro. Subsequently, determination of growth conditions...

Development of female gonads in the chicken is asymmetric. This asymmetry affects gene expression, morphology, and germ cell development; consequently only the left ovary develops into a functional organ, whereas the right ovary remains vestigial. In males, on the other hand, both gonads develop into functional testes. Here, we revisited the development of asymmetric traits in female (and male)...

conclusions comprehensive protection programs with on-the-job training courses for staff members are strongly recommended, as well as, the provision of radiological shields and gonad shielding protocols in radiology departments to reduce the patient’s radiation dose during radiological examinations. materials and methods a retrospective, observational cross-sectional study on the application of...