Mammalian spermatogenesis requires a stem cell pool, a period of amplification of cell numbers, the completion of reduction division to haploid cells (meiosis), and the morphological transformation of the haploid cells into spermatozoa (spermiogenesis). The net result of these processes is the production of massive numbers of spermatozoa over the reproductive lifetime of the animal. One study t...

Research on in vitro spermatogenesis is important for elucidating the spermatogenic mechanism. We previously developed an organ culture method which can support spermatogenesis from spermatogonial stem cells up to sperm formation using immature mouse testis tissues. In this study, we examined whether it is also applicable to mature testis tissues of adult mice. We used two lines of transgenic m...

OBJECTIVE To assess the possibility of using cytological examination and DNA image-analysis of testicular fine-needle aspirates instead of open surgical biopsy in the investigation of infertile men, as testicular biopsy has long been used for investigating infertility but the interpretation of histological slides is usually subjective. PATIENTS AND METHODS Thirty-three men (aged 22-36 years) ...

One of the ways of haploid production is a cross between wheat and maize. Recently success has been achieved in this method, leading to the production of zygotes; these zygotes generally undergo elimination of maize chromosomes and thus lead to production of wheat haploid plant. The purpose of this study was to develop an efficient method of haploid production via maize pollination in short dur...

M aking sperm in a culture dish has been a long-term goal of reproductive biologists. In 2010, a group of investigators from Yokohama, Japan, reinvestigated an organ culture system that was originally used for testicular tissue in the 1960s (1–3). By using better molecular markers, they were able to demonstrate that some cells in this culture system underwent complete meiosis to form round sper...

During spermiogenesis, the histone-to-protamine replacement causes the compaction of the spermatid chromatin. The genes for protamines, PRM-1 and PRM-2, are transcribed in round and elongating spermatids. The transcripts are stored in a translationally-repressed state by the binding of protein repressors before being translated in elongating and elongated spermatids. RNA extracts from homogeniz...

Round spermatids can be collected from testicular biopsy material or occasionally from semen samples. We evaluated the influence of the passage of round spermatids through the male reproductive tract on their reproductive potential. A model of abnormal release of round spermatids from the seminiferous epithelium was created in mature male rats (group A). Additional sham-treated rats of the same...

In all species, reproductive function depends on the ability of the individual to produce functional differentiated gametes. Spermatogenesis is a cyclic process in which diploid spermatogonia differentiate into mature haploid spermatozoa. Thus from a genetic point of view, spermatogenesis can be divided into two phases, namely the diploid and haploid phase. Indeed, this complex differentiation ...