Over the last century the reproduction of sturgeon has been intensively studied par Russian scientists who established a technology for the ranching of alevins which included artificial fertilization of gametes taken from wild broodfish and larvae rearing. More recently, since 1970, major contributions originated from teams in the USA, the EU, Japan and Iran. A rather good knowledge of the repr...

A small portion of cytoplasm is generally retained as the cytoplasmic droplet (CD) on the flagellum of spermatozoa after spermiation in mice. CDs are believed to play a role in osmoadaptation by allowing water entrance or exit. However, many lines of evidence suggest that CDs may have roles beyond osmoregulation. To gain more insights, we purified CDs from murine epididymal spermatozoa and cond...

We trialled the efficacy of various exogenous hormones to induce spermiation, courtship behavior, and spawning in the "endangered" southern bell frog, Litoria raniformis. Intralymphatic administration of Lucrin(®), a synthetic nonapeptide luteinizing hormone releasing hormone (LHRH), was used successfully to induce courting behaviors and ejaculation of spermatozoa in males. Various hormones, in...

Vitamin A has been shown to be essential for a multitude of biological processes vital for mammalian development and homeostasis. Its active metabolite, retinoic acid (RA), is important for establishing and maintaining proper germ cell development. During spermatogenesis, the germ cells orient themselves in very distinct patterns, which have been organized into stages. There is evidence to show...

The goal of this morphometric study was to obtain quantitative information on the seminiferous tubules of Sprague-Dawley rats, including changes seen at various stages of the cycle of the seminiferous epithelium. Tissue from perfusion-fixed testes was embedded in Epon-Araldite; and sections were subjected to morphometric measurements at the light microscopic level, using point counting for volu...

The seminiferous epithelium cycle and developmental stages of spermatids in Clethrionomys rufocanus were observed under a light microscope. The seminiferous epithelium cycle was divided into 8 stages. Type Ad spermatogonia appeared through all stages. Type Ap, In, and B spermatogonia appeared in stages I, II, III, and IV. In the first meiosis prophase, the leptotene spermatocytes appeared from ...

During the haploid phase of spermatogenesis, spermatids undergo a complex remodeling of the paternal genome involving the finely orchestrated replacement of histones by the highly-basic protamines. The associated striking change in DNA topology is characterized by a transient surge of both single- and double-stranded DNA breaks in the whole population of spermatids which are repaired before spe...