Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 2: Changes in spermatid organelles associated with development of spermatozoa

2009 ◽  
pp. NA-NA ◽  
Author(s):  
Louis Hermo ◽  
R.-Marc Pelletier ◽  
Daniel G. Cyr ◽  
Charles E. Smith
Keyword(s):  
Life History ◽  
Germ Cells ◽  
Cycle Life ◽  
Wave Cycle

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 1: Background to spermatogenesis, spermatogonia, and spermatocytes

2009 ◽  
Vol 73 (4) ◽  
pp. 241-278 ◽  
Author(s):  
Louis Hermo ◽  
R.-Marc Pelletier ◽  
Daniel G. Cyr ◽  
Charles E. Smith
Keyword(s):  
Life History ◽  
Germ Cells ◽  
Cycle Life ◽  
Wave Cycle

The Fine Structure of Primordial Germ Cells of the Rat

1973 ◽  
Vol 31 ◽  
pp. 634-635
Author(s):  
E. M. Eddy
Keyword(s):  
Endoplasmic Reticulum ◽  
Life History ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Germ Cells ◽  
Fibrous Material ◽  
Primordial Germ Cells ◽  
The Other ◽  
Large Size ◽  
History Of

Primordial germ cells are readily recognizable in embryos of the rat due to their large size, generally rounded shape and prominent nuclei with uniformly dispersed heterochromatin. They often have blunted pseudopodal processes at one end and small ruffles or trailing processes at the other, characteristics expected from their known ameboid activity- and migratory abilities. Also, the cytoplasm is rich in polyribosomes and contains a modest amount of rough endoplasmic reticulum and the mitochondria are frequently larger and less dense than those of adjacent somatic cells.In addition to these general characteristics, there are features unique to germ cells which allow them to be identified with certainty. These are: 1) small vesicles containing an irregular, dense core and 2) discrete accumulations of fibrous material known as nuage. Both of these features are present in other species and at other times in the life history of germ cells. The dense-cored vesicles have been noted in fetal and early postnatal mouse oogonia and oocytes, and in hamster and rabbit oocytes.

Evolutionary radiation in polychaete ovaries and vitellogenic mechanisms: their possible role in life history patterns

1983 ◽  
Vol 61 (3) ◽  
pp. 487-504 ◽  
Author(s):  
Kevin J. Eckelbarger
Keyword(s):  
Life History ◽  
Germ Cells ◽  
Comparative Studies ◽  
Significant Variation ◽  
Important Process ◽  
Nutrient Storage ◽  
Coelomic Cavity ◽  
Evolutionary Radiation ◽  
Life History Patterns

Two types of oogenesis have evolved in polychaetes: one (extraovarian) in which germ cells are ovulated into the coelomic cavity where they undergo vitellogenesis, and another (intraovarian) in which the germ cells are released from the ovary after or near the completion of vitellogenesis. There are many mechanisms of yolk synthesis and significant variation as to the sources of yolk precursors, their route of entry into developing oocytes, and the oocytic organelles involved in yolk synthesis. The evolution of the coelom and its role in nutrient storage and transfer, as well as the origin of germ cells, are intimately related to the evolution of vitellogenic mechanisms in polychaetes. Comparative studies have revealed a correlation between mechanisms of yolk synthesis and the breeding patterns of polychaetes with the rate and type of vitellogenesis being related to the frequency of breeding. Vitellogenic mechanisms in polychaetes are compared with those of other metazoans in an effort to better understand the evolution of this important process and to identify primitive and derived features of yolk synthesis within the Polychaeta.

scholarly journals A Contribution to Our Knowledge of the Life History of Arenicola Marina L.

1948 ◽  
Vol 27 (3) ◽  
pp. 554-580 ◽  
Author(s):  
G. E. Newell
Keyword(s):  
Life History ◽  
Breeding Season ◽  
Germ Cells ◽  
Full Moon ◽  
Body Cavity ◽  
The Body ◽  
Spawning Period ◽  
Arenicola Marina ◽  
History Of ◽  
New Moon

The breeding season of the lugworms of the Whitstable area is a sharply defined one, extending for 14 days between the new moon and full moon spring tides in the second half of October. Spawning begins slowly and reaches a maximum at the intervening neap tides and then declines in intensity.Both eggs and sperms are discharged from the burrows at extreme low water to lie on the surface of the sand. Here fertilization occurs.No germ cells were detected in the body cavity from November to June, but from August onwards to the end of October 98% of the adult worms are ripe.At the end of the spawning period about 40% of the adults die.A brief description of gametogenesis and of the mature gametes is given.Germ cells are discharged through the nephridia.

The gametogenic cycle and life history of Nicolea uspiana (Polychaeta: Terebellidae) on the south-east coast of Brazil

2014 ◽  
Vol 94 (5) ◽  
pp. 925-933
Author(s):  
André Rinaldo Senna Garraffoni ◽  
Leonardo Querobim Yokoyama ◽  
Antonia Cecília Zacagnini Amaral
Keyword(s):  
Life History ◽  
Germ Cells ◽  
Anterior Part ◽  
Follicle Cells ◽  
Maximum Diameter ◽  
Coelomic Fluid ◽  
Maturation Stage ◽  
Gametogenic Cycle ◽  
Male Gametes ◽  
History Of

The gametogenic cycle and life history of Nicolea uspiana (Nogueira, 2003) (Polychaeta: Terebellidae) was studied by taking monthly samples over a 13 month period. Each month, 10 females were sorted; 50 oocytes were removed from the coelom of each specimen, and the maximum diameter was determined. Additionally, 10 males were sorted and 100 gametes were randomly selected from each specimen to evaluate their shape and maturation stage. This species is gonochoric and exhibits slight external sexual dimorphism (in the shape of the nephridial papillae). The sex-ratio of N. uspiana was 2.4 male for each female. The initial gametic stages of both sexes are produced in special structures called nephromixia. Oogenesis is extra-ovarian, and the germ cells are clumped and surrounded by follicle cells. These cells are ovulated into the coelomic fluid, and yolk synthesis occurs in this cavity. The maximum diameter of oocytes measured, 225 µm, showed that these eggs fall into the size-range for lecithotrophy. Furthermore, N. uspiana is an iteroparous species, as the mature individuals can breed several times during their lifetime. Male gonads release germ cells early in development, and sperm maturation also occurs in the coelomic fluid. The male gametes consist of flattened plaques of germ cells attached on their anterior part by a cytophore assuming a rosette-like appearance. Following maturation of the male cells, the spermatids produce arrays of stiffly vibratile tails, assuming a morula shape. The reproductive patterns and life history of the terebellids are also discussed.

Epididymosomes: the black box of Darwin’s pangenesis?

2021 ◽  
Author(s):  
Hamid Reza Nejabati ◽  
Vahideh Shahnazi ◽  
Yousef Faridvand ◽  
Nazila Fathi-Maroufi ◽  
Zahra Bahrami-Asl ◽  
...  
Keyword(s):  
Life History ◽  
Germ Cells ◽  
Wide Spectrum ◽  
Cell Communication ◽  
Black Box ◽  
The Body ◽  
Environmental Stressors ◽  
External Information ◽  
Historical Events ◽  
Attractive Candidate

Abstract Darwin, in the pangenesis theory, imagined particles, named as ‘gemmules’, which are released from all (‘pan’) cells of the body. By cell–cell communication and also circulation through the body, they finally reach the germ cells to participate in the generation (‘genesis’) of the new individual. It has been shown that circulatory exosomes are affected by environmental stressors and they can reach the parental germ cells. Therefore, in the mirror of his theory, circulatory exosomes could interact with epididymosomes: epididymis-derived exosomes which have a wide spectrum of variation in content and size, are very sensitive to environmental stressors, and may be involved in translating external information to the germ cells. The protein and RNA cargo would be transferred by epididymosomes to sperm during sperm maturation, which would be then delivered to the embryo at fertilization and inherited by offspring. Therefore, in this study, we will briefly discuss Darwin’s pangenesis theory and its possible relation with epididymosomes. We believed that epididymosomes could be considered as an attractive candidate for the storage of RNA contents, changing the epigenome of the next generations, and allowing the reappearance acquired characteristics of ancestors. Therefore, epididymosomes, as a black box of Darwin’s pangenesis, may unravel parental life history and also disclose the historical events that affect the life of offspring.

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