aquatics are a source of bioactive compounds that these compounds have different properties such as antimicrobial activity. in this study, antibacterial activity of methanol, chloroform and hexane extracts from body wall, gonad and intestine of sea cucumber holothuria leucospilota was evaluated against bacillus subtilis, pseudomonas aeruginosa and staphylococcus aureus. bioactive compounds of b...

In wild-type Caenorhabditis elegans, the hermaphrodite gonad is a symmetrical structure, whereas the male gonad is asymmetric. Two cellular processes are critical for the generation of these sexually dimorphic gonadal shapes during early larval development. First, regulatory "leader" cells that control tube extension and gonadal shape are generated. Second, the somatic gonadal precursor cells m...

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...

Geoduck clams (Panopea generosa) are an increasingly important fishery and aquaculture product along the eastern Pacific coast from Baja California, Mexico, to Alaska. These long-lived clams are highly fecund, although sustainable hatchery production of genetically diverse larvae is hindered by the lack of sexual dimorphism, resulting in asynchronous spawning of broodstock, unequal sex ratios, ...

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,...

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...

This study describes and recognises, using histological and microscopical examinations on a morphometrical basis, several gonad traits through the early life stages of Chiton articulatus and C. albolineatus. Gonadal ontogenesis, gonad development stages, sexual differentiation, onset of the first sexual maturity, and growth sequences or "early life stages" were determined. In addition, allometr...

The development of any organ system requires a complex interplay of cellular signals to initiate the differentiation and development of the heterogeneous cell and tissue types required to carry out the organs' functions. In this way, an extracellular stimulus is transmitted to an intracellular target through an array of interacting protein intermediaries, ultimately enabling the target cell to ...

Although the genetic sex of an embryo is determined at conception by the presence or absence of the Y chromosome, both females and males have bipotential, undifferentiated gonads early in their development. Genes and testicular hormones direct differentiation into either testes or ovaries. The first relevant gene to be identified was the Y-linked master regulatory gene, SRY, since when several ...

Mutations in tcl-2 cause defects in the specification of the fates of the descendants of the TL and TR blast cells, whose polarity is regulated by lin-44/Wnt and lin-17/frizzled, during Caenorhabditis elegans development. In wild-type animals, POP-1/TCF/LEF, is asymmetrically distributed to the T cell daughters, resulting in a higher level of POP-1 in the nucleus of the anterior daughter. The P...