Hypotheses for the functions of intercellular bridges in male germ cell development and its cellular mechanisms

Guo, Guiqiang

doi:10.1016/s0022-5193(04)00111-0

Cited by 12 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A coordinate interaction between somatic and germ line tissues creates an organ, followed by the synchronization of spermiogenic cells by the formation of intercellular bridges connecting clonal cells to syncytia. These structures have a nutritive function as well as facilitating the sharing of specific haploid gene products (Morales et al 1998;Guo and Zheng 2004). However, we did not find any of these basic synapomorphies in Dicyema typus, which in contrast, shows an aberrant model in which spermiogenesis has been reduced to the cytoplasmic interior of a sole somatic cell, the infusorigen's axial cell, which functions as somatic gonadal founder cell.…”

Section: Discussioncontrasting

confidence: 69%

Dicyemid’s dilemma: structure versus genes. The unorthodox structure of dicyemid reproduction

Czaker

2011

Cell Tissue Res

View full text Add to dashboard Cite

The clear phylogenetic status of the enigmatic Phylum Dicyemida is still uncertain. Their primitive body plan lacks essential metazoan synapomorphies, while genetic data favor a kinship with higher lophotrochozoans. This ultrastructural study increases the confusion about this phylum by presenting an unusual gonad and sperm structure lacking all synapomorphies essential for the various phyla of the lophotrochozoans, either free-living ones or parasites. In Dicyema typus, gonadogenesis is reduced to a single somatic cell, i.e., the infusorigen's axial cell that functions as a somatic gonadal founder cell as soon as a spermatogonium takes residence in its cytoplasm. The spermiogenic cells resulting therefrom are not connected by intercellular bridges and permanently contain a bundle of microtubules in their cytoplasm, obviously a kind of "dormant" spindle having assembled without centrosomes. Primary spermatocytes develop so-called polycomplexes, multiple synaptinemal complexes. The structure of the sperm is based on a certain kind of somatic cell that has been minimally adapted to function as a sperm. The mature sperm consists in only three organelles: an ovoid nucleus with a somatic chromatin structure, numerous pore complexes and a centrally arranged cluster of coiled tubular structures; a bundle of microtubules embedded into a rim running along the nucleus longitudinal surface, projecting out of the cell like a spear; and a lipid vesicle tightly attached to one pole of the nucleus, touching there the adjacent bundle of microtubules. Immunelectron microscopy confirms the somatic condition of mature sperm, revealing somatic histone H1 immunoreactivity over the nucleus, which can be interpreted as synapomorphy shared with Protozoa, Porifera and Cnidaria. Fertilization occurs as selfing, where the sperm penetrates, "bundle of microtubules first", a primary oocyte attached vis-à-vis on the other side of the plasma membrane of the infusorigen's axial cell. This somatic situation points to an ancient evolutionary model rather than to a condition caused by retrogression due to their life as commensals.

show abstract

Section: Discussioncontrasting

confidence: 69%

Dicyemid’s dilemma: structure versus genes. The unorthodox structure of dicyemid reproduction

Czaker

2011

Cell Tissue Res

View full text Add to dashboard Cite

show abstract

“…Through the intercellular channels cytoplasmic exchange occurs and is believed to promote synchrony within the microsporocyte mass (Scott et al, 2004). After Guo and Zheng (2004) the intercellular connections (bridges) are necessary to exchange organelles between haploid cells. Some electron -dense bodies similar to those detected in Tillandsia were already Figs.…”

Section: Discussionmentioning

confidence: 99%

The ultrastructure of the development of Tillandsia (Bromeliaceae) trichome

Papini

Tani

Falco

et al. 2010

Flora - Morphology, Distribution, Functional Ecology of Plants

View full text Add to dashboard Cite

“…Kubrakiewicz, 1991;Bűning, 1994;Pepling and Spradling, 1998;Kloc et al, 2004;Miyazaki and Biliński, 2006;Pepling, 2006). The role of germline cysts seems to be different in male and female lines and it is still far from being fully explained (Pepling andSpradling, 1998, 2001;Pepling et al, 1999;Matova and Cooley, 2001;Guo and Zheng, 2004;Kloc et al, 2004). Germline cysts are formed in E. johanssoni just as in all of the clitellates studied to date.…”

Section: Germline Cystsmentioning

confidence: 99%

An ultrastructural study of the ovary cord organization and oogenesis in Erpobdella johanssoni (Annelida, Clitellata: Hirudinida)

Ahmed

Tekaya

Małota

et al. 2013

Micron

View full text Add to dashboard Cite

Hypotheses for the functions of intercellular bridges in male germ cell development and its cellular mechanisms

Cited by 12 publications

References 0 publications

Dicyemid’s dilemma: structure versus genes. The unorthodox structure of dicyemid reproduction

Dicyemid’s dilemma: structure versus genes. The unorthodox structure of dicyemid reproduction

The ultrastructure of the development of Tillandsia (Bromeliaceae) trichome

An ultrastructural study of the ovary cord organization and oogenesis in Erpobdella johanssoni (Annelida, Clitellata: Hirudinida)

Contact Info

Product

Resources

About