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Sie sind hier: Startseite Forschung Miething, Andreas PD. Research

Project Overview

Research Topics

  • Establishment of mammalian spermatogenesis
  • Significance of the Sertoli cell barrier
  • Clonal mode of male germ cell proliferation
  • Differentiation of Purkinje cell neurons in the cerebellum

Establishment of mammalian spermatogenesis

The prepubertal period of testis differentiation ranges from sexual differentiation to the time, when immature germ cells transform into the first "mature" stem cells of spermatogenesis. Germ cells (prospermatogonia) pass through successive phases of enhanced mitotic proliferation or quiescence, while the somatic (Sertoli) cells differentiate and continuously proliferate.
During pubertal development of the testis, germ cells pass initially through the complete succession of spermatogenic differentiation. Both the complex process of germ cell proliferation and differentiation and the cyclic course of spermatogenesis are established.
Detailed morphological and cell kinetic analyses emphasize and specify the close structural and functional interdependence of germ cell and somatic (Sertoli and Leydig) cell development during this period.

Publications:
Miething A (1993) Proliferative activity of the developing seminiferous epithelium during prespermatogenesis in the golden hamster testis measured by bromodeoxyuridine labeling. Anat Embryol 187:249-258

Miething A (1998) The establishment of spermatogenesis in the seminiferous epithelium of the pubertal golden hamster (Mesocricetus auratus). Adv Anat Embryol Cell Biol 140:1-95

Miething A (1999) The degenerative fate of germ cells not conforming to stage in the pubertal golden hamster testis. J Anat 193:519-527

Significance of the Sertoli cell barrier

The pattern of establishment of the Sertoli cell barrier is related to the developmental level reached by the spermatocytes in the initial spermatogenic cycle. Several observations point to the hypothesis that this barrier is important to shield a (basal) mitotic milieu against an (adluminal) meiotic one within the epithelium. Without this barrier, mitotic germ cells might be affected by a specific mitotic arrest and subsequent degeneration.

Publications:
Miething A (1998) The establishment of spermatogenesis in the seminiferous epithelium of the pubertal golden hamster (Mesocricetus auratus). Adv Anat Embryol Cell Biol 140:1-95

Miething A (2002) The bridge-partitioning complex is absent in a distinct type of defective germ cell division in the gonads of the golden hamster. Cell Tissue Res 308:103-8

Miething A (2005) Arrested germ cell divisions in the ageing human testis. Andrologia 37:10-16

Clonal mode of male germ cell proliferation

Most of the mitotic and all meiotic male germ cell divisions display an incomplete cytokinesis. By means of the resulting intercellular bridges, daughter germ cells remain linked to one another (picture below, red arrows) and thus go through the process of spermatogenesis as synchronously developing germ cell clones:

germ cell clone

During the successive divisions, the pre-existing bridges are transiently closed by the bridge-partitioning complex, a membranous structure evolving within the bridge channel (see picture below):

bpc

 

 

 

Publications:
Miething A (1990) Intercellular bridges between germ cells in the immature golden hamster testis: evidence for clonal and non-clonal mode of proliferation. Cell Tissue Res 262:559-567

Miething A (1995) The bridge-partitioning complex of germ-cell intercellular bridges in the testis of the golden hamster. Cell Tissue Res 281:359-365

Miething A (2003) The formation and dissolution of the bridge-partitioning complex in intercellular bridges of dividing germ cells in the testis of the golden hamster. J Submicrosc Cytol Pathol 35:271-276

Miething A (2010) Local desynchronization of cellular development within mammalian male germ cell clones. Ann Anat 192:247-250

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