BACKGROUND Benzo(a)pyrene (BaP) is an endocrine toxicant that is widely distributed in the environment. The adverse effects of BaP on fertility are well documented, however its effects on fertility in the subsequent generations are not known. We aimed to investigate the transgenerational effects of BaP on male fertility in mice. METHODS Six-week-old male mice (F0) were orally administered BaP...

Knowledge about the mechanism that establishes embryonic polarity is fundamental in understanding mammalian development. In re-addressing several controversial claims, we recently proposed a model in which mouse embryonic polarity is not specified until the blastocyst stage. Before fertilization, the fully differentiated oocyte has been characterized as "polarized," and we indeed observed that ...

Background: To clarify the mechanism of sperm penetration through the zona pellucida, the flagellar force generated by a hyperactivated spermatozoon was evaluated using the resistive force theory applied to the hyperactivated flagellar waves that were obtained from the mammalian spermatozoa. Materials and Methods: The hydrodynamic calculation of the flagellar force of the activated (non-hyperac...

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 pol...

introduction: the frequency of sperm pcc indiction in normal and infertile men was investigated. material and methods: zona – free hamster oocyte were retrieved after super ovulation by pmsg and hcg infection. following treatment with hyaloronidase, zona was removed by trypsin digestion. sperms were classified with sperms, and then transferred to fresh media containing colcemid. slides were pre...

A typical mammalian egg is surrounded by an outer layer of about 3,000 cumulus cells embedded in an extracellular matrix rich in hyaluronic acid. A current, widely proposed model is that the fertilizing sperm, while it is acrosome intact, passes through the cumulus cell layer and binds to the egg zona pellucida. This current model lacks a well-supported explanation for how sperm penetrate the c...

Electron microscope observations of osmium tetroxide-fixed rat eggs indicate that small nucleoli are extruded from pronuclei in a sharply demarcated time period after sperm penetration. Approximately 4(1/2) hours after sperm penetration, fine fibrous material aggregated in distinct loci along the inner surface of the nuclear envelope and condensed into small, dense bodies. The term tertiary nuc...

INTRODUCTION It is widely recognized that all that fathers essentially contribute to the next generation is half of their genome, and mature sperm cells are transcriptionally and translationally inactive. However, an increasing number of reports have shown that RNAs were present in human sperm detected by using RT-PCR, differential display, in situ hybridization and microarrays [1]. One study s...

Conventional semen analysis solely is not completely adequate to predict pregnancy outcomes. Therefore, advanced sperm function tests have been developed and introduced to clinical practice. These tests use different methods and techniques to evaluate different stages of fertilization steps. In this review, we reported some commonly used sperm function tests: sperm penetration assay, sperm-zona...