Evidence of male germ cell redifferentiation into female germ cells in planarian regeneration

Development ◽  
1982 ◽  
Vol 70 (1) ◽  
pp. 29-36
Author(s):  
V. Gremigni ◽  
M. Nigro ◽  
I. Puccinelli
Keyword(s):  
Germ Cells ◽  
Somatic Cells ◽  
The Body ◽  
Diploid Male ◽  
Female Gonad ◽  
Anterior Portion ◽  
Male Germ Cells ◽  
Blastema Formation ◽  
Planarian Regeneration ◽  
Undifferentiated Cells

The source and fate of blastema cells are important and still unresolved problems in planarian regeneration. In the present investigation we have attempted to obtain new evidence of cell dedifferentiation-redifferentiation by using a polyploid biotype of Dugesia lugubris s.1. This biotype is provided with a natural karyological marker which allows the discrimination of triploid embryonic and somatic cells from diploid male germ cells and from hexaploid female germ cells. Thanks to this cell mosaic we previously demonstrated that male germ cells take part in blastema formation and are then capable of redifferentiating into somatic cells. In the present investigation sexually mature specimens were transected behind the ovaries and the posterior stumps containing testes were allowed to regenerate the anterior portion of the body. Along with the usual hexaploid oocytes, a small percentage (3.2%) of tetraploid oocytes were produced from regenerated specimens provided with new ovaries. By contrast only hexaploid oocytes were produced from control untransected specimens. The tetraploid oocytes are interpreted as original diploid male germ cells which following the transection take part in blastema formation and then during regeneration redifferentiate into female germ cells thus doubling their chromosome number as usual for undifferentiated cells entering the female gonad in this biotype.

On the role of germ cells in planarian regeneration

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 65-76
Author(s):  
V. Gremigni ◽  
C. Miceli ◽  
E. Picano
Keyword(s):  
Germ Cells ◽  
Dna Content ◽  
Somatic Cells ◽  
Diploid Male ◽  
Dna Amount ◽  
Male Germ Cells ◽  
Blastema Formation ◽  
Planarian Regeneration ◽  
Cytophotometric Analysis

Previous findings by our group have shown how primordial male germ cells take part in regenerative blastema formation in planarians by migrating to the wound. The role of these cells in rebuilding transected tissues has been investigated in a population of Dugesia lugubris s.l. which is particularly suited for our purpose. In fact, these planarians provide a clear karyological marker to distinguish diploid male germ cells (2n = 8) from tryploid embryonic or somatic cells (3n = 12). In this study we employed the cytophotometric analysis of the nuclear Feulgen-DNA content in order to distinguish non-replicating male germ cells from reserve and somatic cells. The Feulgen-DNA content in cells from the gonad-free caudal area was measured after complete regeneration. Most non-replicating cells (94–95%) were found to have a DNA amount typical of cells previously estimated as triploid. Some (5–6%) nuclei containing a DNA amount typical of cells previously estimated as diploid male gonia were also found. These findings seem to support the view that primordial male germ cells also participate in rebuilding somatic tissues according to the field influence they encounter during regeneration. The possibility that metaplasia (or cell transdifferentiation) may occur in planarians is finally discussed.

On the role of germ cells in planarian regeneration

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 53-63
Author(s):  
V. Gremigni ◽  
C. Miceli ◽  
I. Puccinelli
Keyword(s):  
Chromosome Number ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Karyological Analysis ◽  
Blastema Formation ◽  
Planarian Regeneration ◽  
Somatic Tissues ◽  
Caudal Area ◽  
Complete Regeneration

Specimens from a polyploid biotype of Dugesia lugubris s.l. were used to clarify the role and fate of germ cells during planarian regeneration. These specimens provide a useful karyological marker because embryonic and somatic cells (3n = 12) can be easily distinguished from male (2n = 8) and female (6n = 24) germ cells by their chromosome number. We succeed in demonstrating how primordial germ cells participate in blastema formation and take part in rebuilding somatic tissues. This evidence was obtained by cutting each planarian specimen twice at appropriate levels. The first aimed to induce primordial germ cells to migrate to the wound. The second cut was performed after complete regeneration and aimed to obtain a blastema from a cephalic or caudal area devoid of gonads. A karyological analysis of mitotic cells present in each blastema obtained after the second cut provided evidence that cells, originally belonging to the germ lines, are still present in somatic tissues even months after complete regeneration. The role of primordial germ cells in planarian regeneration was finally discussed in relation to the phenomenon of metaplasia or transdifferentiation.

377 SPERMATOZOA RETRIEVED FROM MALE MICE FROZEN FOR 15 YEARS CAN PRODUCE NORMAL OFFSPRING

2007 ◽  
Vol 19 (1) ◽  
pp. 304
Author(s):  
N. Ogonuki ◽  
K. Mochida ◽  
H. Miki ◽  
K. Inoue ◽  
T. Iwaki ◽  
...  
Keyword(s):  
Germ Cells ◽  
Mammalian Species ◽  
The Body ◽  
Freezing And Thawing ◽  
Abdominal Incision ◽  
Closely Related Species ◽  
Male Germ Cells ◽  
Testicular Spermatozoa ◽  
One Year ◽  
Normal Offspring

Cryopreservation of male germ cells is a strategy to conserve animal species and strains of animals valuable to biomedical research. However, to minimize damage that may occur during freezing and thawing, complex cryopreservation protocols that have been optimized for the stage and species of male germ cells are usually employed. Recently, we have found that mouse male germ cells can be cryopreserved at -80�C by freezing the whole epididymides and testes without cryoprotectant for at least one year (Ogonuki et al. 2006 Reprod. Fertil. Dev. 18, 286 abst). This study was undertaken to determine whether mouse male germ cells retrieved from the bodies of mice frozen at -20�C for 15 years could produce normal offspring by microinsemination. Mature males of BALB/c-nude and C3H/He (8 weeks of age) were euthanized by overdose of pentobarbital on February 20 and March 8, 1991, respectively, and kept in a -20�C freezer. The frozen body was thawed about 15 years after freezing (February 2006) by putting it in a water bath until the outer surface of the body was softened. The body was then removed from the water, and the testes were isolated through an abdominal incision. Testicular spermatozoa were collected from the testes and microinseminated into B6D2F1 oocytes. Within 24 h after sperm injection, over 80% of oocytes developed into 2-cell embryos. Apparently normal pups were born after embryo transfer in both strains of mice at rates of 21% (17/81) and 12% (12/97) per transfer, respectively. Two pups from the BALB/c-nude group died shortly after Caesarian section due to respiratory failure, but others grew normally and were proven to be fertile when they matured (at least 19 mice out of 20 mice tested). We further mated these F1 offspring and confirmed that the nude gene was safely propagated. The present study demonstrates that spermatozoa can retain their fertilizing ability in frozen whole bodies for longer than we anticipated. If spermatozoa of extinct mammalian species (e.g. woolly mammoth) can be retrieved from animal bodies that were kept frozen in permanent frost, live animals might be restored by injecting them into oocytes from females of closely related species.

scholarly journals Fertilization of mouse oocytes using somatic cells as male germ cells

2001 ◽  
Vol 3 (3) ◽  
pp. 205-211 ◽  
Author(s):  
Orly Lacham-Kaplan ◽  
Rob Daniels ◽  
Alan Trounson
Keyword(s):  
Germ Cells ◽  
Somatic Cells ◽  
Male Germ Cells ◽  
Mouse Oocytes

Regeneration and pattern formation in planarians

Development ◽  
1984 ◽  
Vol 83 (1) ◽  
pp. 63-80
Author(s):  
Emili Saló ◽  
Jaume Baguñà
Keyword(s):  
Pattern Formation ◽  
Mitotic Activity ◽  
Intermediate Stage ◽  
Point Of View ◽  
Blastema Formation ◽  
Biphasic Pattern ◽  
Spatial Point ◽  
Planarian Regeneration ◽  
Undifferentiated Cells ◽  
S Period

Mitotic activity during regeneration in the planarian Dugesia (G) tigrina shows a biphasic pattern, with a first maximum at 4–12 h, a second and higher maximum at 2–4 days, and a relative minimum in between. The first peak is mainly due to pre-existing G2 cells entering mitosis shortly after cutting, whereas the second maximum is due to cells that divide after going through the S period from the onset of regeneration. From a spatial point of view, the highest mitotic values are found in stump (postblastema) regions near the wound (0–300 µm), though regions far from it also show increased mitotic values but always lower overall values. As regeneration continues the postblastema maximum shifts slightly to more proximal regions. In contrast, no mitosis has been found within the blastema, even though the number of blastema cells increases steadily during regeneration. These results suggest that blastema in planarians forms through an early accumulation of undifferentiated cells at the wound boundary, and grows by the continuous local migration of new undifferentiated cells from the stump to the base of blastema. The results obtained demonstrate that blastema formation in planarians occurs through mechanisms somewhat different to those shown to occur in the classical epimorphic models of regeneration (Annelida, Insecta, Amphibia), and suggest that planarian regeneration could represent an intermediate stage between morphallactic and epimorphic modalities of regeneration.

Cell movement in intact and regenerating planarians. Quantitation using chromosomal, nuclear and cytoplasmic markers

Development ◽  
1985 ◽  
Vol 89 (1) ◽  
pp. 57-70
Author(s):  
Emili Saló ◽  
Jaume Baguñà
Keyword(s):  
Cell Movement ◽  
Chromosomal Marker ◽  
Blastema Formation ◽  
Differentiated Cells ◽  
Planarian Regeneration ◽  
Latex Beads ◽  
Undifferentiated Cells ◽  
Speed Up ◽  
X Irradiation ◽  
Parenchymal Cells

One of the tenets of Wolff and Dubois' ‘neoblast theory’ of planarian regeneration (Wolff & Dubois, 1948) is that blastema is mainly formed by the accumulation of undifferentiated parenchymal cells (neoblasts) that can migrate, if needed, over long distances to the wound. That neoblasts migrate was claimed by these authors after partial X-irradiation, and total Xirradiation and grafting using planarian strains of different pigmentation. From this they suggested that migration of neoblasts is stimulated by the wound and directed towards it. To study the nature and extent of such ‘migration’ in intact and regenerating organisms, and in order to avoid the flaws of using pigmentation as a marker, we made grafts between sexual and asexual races of Dugesia(S)mediterranea that differ in a chromosomal marker, and between diploid and tetraploid biotypes of Dugesia(S)polychroa that differ in nuclear size. Also, fluorescent latex beads were used as cytoplasmic markers to follow ‘migration’ of differentiated cells. The hosts were irradiated or non-irradiated intact and regenerating organisms. The results show that: 1) movement of graft cells into host tissues occurs in intact organisms at a rate of ≃40µm/day, and that this increases up to ≃75µm/day in irradiated hosts; 2) movement of cells occurs evenly in all directions; 3) regeneration does not speed up rate of movement nor drives cells preferentially to the wound; 4) spreading of cells is mainly due to the movement of undifferentiated cells (neoblasts); and 5) higher rates of movement are correlated with higher mitotic indexes. From this, it is concluded that the so-called ‘migration’ of neoblasts is not a true cell migration but the result of the slow, even and progressive spreading of these cells mainly caused by random movements linked to cell proliferation. The implications of these results for blastema formation and the origin of blastema cells are discussed.

Gametogenesis and Spawning Induction in Batissa violacea Lamarck, (1806) at Cagayan River, Philippines

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
EUNICE A. LAYUGAN ◽  
SUSUMU SEGAWA ◽  
LIBERATO V. LAURETA ◽  
JESSE D. RONQUILLO
Keyword(s):  
Data Analysis ◽  
Germ Cells ◽  
Aquatic Ecology ◽  
Mature Stage ◽  
Female Gonad ◽  
Freshwater Bivalve ◽  
Descriptive Data ◽  
Male Germ Cells ◽  
Cytological Characteristics ◽  
First Time

Batissaviolacea Lamarck (l806) locally known as “cabibi” is considered endemic in Cagayan River at Lallo, Philippines and the most expensive freshwater bivalve in the region. This study described through monthly histological examination the cytological characteristics of gametogenesis and sexual dimorphism of the gonad of B. violacea collected from the wild, and determined spawning response using serotonin. Eight category sizes of the species were established, and 10 samples from each size were processed. Gonads were preserved, and subjected for histological processes to confirm gametogenesis. Using descriptive data analysis, confirmation of the identified mature stage at 31-35 mm was further tested through induction of serotonin. Results showed progressive stages of sperm formation in male follicles. Follicles could be seen in clusters and identified as to their sizes from spermatogonia, spermatocytes, spermatids and spermatozoa. Growing female follicles appeared attached to a cytoplasmic stalk in different sizes and shapes. Initially male germ cells appeared tiny and became concentrated at the lumen in radiating bands as they become mature. Likewise, mature oocytes with enlarged nucleus and tiny nucleolus fill the center of the lumen of the female gonad was observed. B. violacea successfully spawn using either 0.2 ml or 0.5 ml earlier (0.21 hour) compared to 36.70 hour when no injection was administered. This is a first time report in the country along the possibility of breeding the species in captivity.Keywords: Aquatic ecology, Batissa violacea, gametogenesis, Cagayan River, induced spawning,experimental design, Cagayan river

scholarly journals Transcriptomic analysis of dead end knockout testis reveals germ cell and gonadal somatic factors in Atlantic salmon

2019 ◽  
Author(s):  
Lene Kleppe ◽  
Rolf Brudvik Edvardsen ◽  
Tomasz Furmanek ◽  
Eva Andersson ◽  
Kai Ove Skaftnesmo ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Germ Cell ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Somatic Cells ◽  
The Body ◽  
Genetic Introgression ◽  
Transcriptome Data ◽  
Dead End ◽  
Testis Tissue

Abstract Background Sustainability challenges are currently hampering an increase in salmon production. Using sterile salmon can solve problems with precocious puberty and genetic introgression from farmed escapees to wild populations. Recently sterile salmon was produced by knocking out the germ cell-specific dead end (dnd). Several approaches may be applied to inhibit Dnd function, including gene knockout, knockdown or immunization. Since it is challenging to develop a successful treatment against a gene product already existing in the body, alternative targets are being explored. Germ cells are surrounded by, and dependent on, gonadal somatic cells. Targeting genes essential for the survival of gonadal somatic cells may be good alternative targets for sterility treatments. Our aim was to identify and characterize novel germ cell and gonadal somatic factors in Atlantic salmon. Results We have for the first time analysed RNA-sequencing data from germ cell-free (GCF)/dnd knockout and wild type (WT) salmon testis and searched for genes preferentially expressed in either germ cells or gonadal somatic cells. To exclude genes with extra-gonadal expression, our dataset was merged with available multi-tissue transcriptome data. We identified 389 gonad specific genes, of which 194 were preferentially expressed within germ cells, and 11 were confined to gonadal somatic cells. Interestingly, 5 of the 11 gonadal somatic transcripts represented genes encoding secreted TGF-β factors; gsdf, inha, nodal and two bmp6-like genes, all representative vaccine targets. Of these, gsdf and inha had the highest transcript levels. Expression of gsdf and inha was further confirmed to be gonad specific, and their spatial expression was restricted to granulosa and Sertoli cells of the ovary and testis, respectively. Finally, we show that inha expression increases with puberty in both ovary and testis tissue, while gsdf expression does not change or decreases during puberty in ovary and testis tissue, respectively. Conclusions This study contributes with transcriptome data on salmon testis tissue with and without germ cells. We provide a list of novel and known germ cell- and gonad somatic specific transcripts, and show that the expression of two highly active gonadal somatic secreted TGF-β factors, gsdf and inha, are located within granulosa and Sertoli cells.

scholarly journals The Golgi Glycoprotein MGAT4D is an Intrinsic Protector of Testicular Germ Cells From Mild Heat Stress

2019 ◽  
Author(s):  
Ayodele Akintayo ◽  
Meng Liang ◽  
Boris Bartholdy ◽  
Frank Batista ◽  
Jennifer Aguilan ◽  
...  
Keyword(s):  
Heat Stress ◽  
Germ Cell ◽  
Germ Cells ◽  
The Body ◽  
Wild Type ◽  
Tgfβ Signaling ◽  
Male Germ Cells ◽  
Mild Heat ◽  
Intrinsic Mechanism ◽  
Shock Response

AbstractMale germ cells are sensitive to heat stress and testes must be maintained outside the body for optimal fertility. However, no germ cell intrinsic mechanism that protects from heat has been reported. Here, we identify the germ cell specific Golgi glycoprotein MGAT4D as a protector of male germ cells from heat stress. Mgat4d is highly expressed in spermatocytes and spermatids. Unexpectedly, when the Mgat4d gene was inactivated globally or conditionally in spermatogonia, or mis-expressed in spermatogonia, spermatocytes or spermatids, neither spermatogenesis nor fertility were affected. On the other hand, when males were subjected to mild heat stress of the testis (43°C for 25 min), germ cells with inactivated Mgat4d were markedly more sensitive to the effects of heat stress, and transgenic mice expressing Mgat4d were partially protected from heat stress. Germ cells lacking Mgat4d generally mounted a similar heat shock response to control germ cells, but could not maintain that response. Several pathways activated by heat stress in wild type were induced to a lesser extent in Mgat4d[−/−] heat-stressed germ cells (NFκB response, TNF and TGFβ signaling, Hif1α and Myc genes). Thus, the Golgi glycoprotein MGAT4D is a novel, intrinsic protector of male germ cells from heat stress.

scholarly journals The Transformation of the Centrosome into the Basal Body: Similarities and Dissimilarities between Somatic and Male Germ Cells and Their Relevance for Male Fertility

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2266
Author(s):  
Constanza Tapia Contreras ◽  
Sigrid Hoyer-Fender
Keyword(s):  
Germ Cells ◽  
Basal Body ◽  
Male Fertility ◽  
Round Spermatid ◽  
Clinical Diagnostics ◽  
The Body ◽  
Microtubule Organizing Center ◽  
Male Germ Cells ◽  
Sperm Tail ◽  
Acrosomal Vesicle

The sperm flagellum is essential for the transport of the genetic material toward the oocyte and thus the transmission of the genetic information to the next generation. During the haploid phase of spermatogenesis, i.e., spermiogenesis, a morphological and molecular restructuring of the male germ cell, the round spermatid, takes place that includes the silencing and compaction of the nucleus, the formation of the acrosomal vesicle from the Golgi apparatus, the formation of the sperm tail, and, finally, the shedding of excessive cytoplasm. Sperm tail formation starts in the round spermatid stage when the pair of centrioles moves toward the posterior pole of the nucleus. The sperm tail, eventually, becomes located opposed to the acrosomal vesicle, which develops at the anterior pole of the nucleus. The centriole pair tightly attaches to the nucleus, forming a nuclear membrane indentation. An articular structure is formed around the centriole pair known as the connecting piece, situated in the neck region and linking the sperm head to the tail, also named the head-to-tail coupling apparatus or, in short, HTCA. Finally, the sperm tail grows out from the distal centriole that is now transformed into the basal body of the flagellum. However, a centriole pair is found in nearly all cells of the body. In somatic cells, it accumulates a large mass of proteins, the pericentriolar material (PCM), that together constitute the centrosome, which is the main microtubule-organizing center of the cell, essential not only for the structuring of the cytoskeleton and the overall cellular organization but also for mitotic spindle formation and chromosome segregation. However, in post-mitotic (G1 or G0) cells, the centrosome is transformed into the basal body. In this case, one of the centrioles, which is always the oldest or mother centriole, grows the axoneme of a cilium. Most cells of the body carry a single cilium known as the primary cilium that serves as an antenna sensing the cell’s environment. Besides, specialized cells develop multiple motile cilia differing in substructure from the immotile primary cilia that are essential in moving fluids or cargos over the cellular surface. Impairment of cilia formation causes numerous severe syndromes that are collectively subsumed as ciliopathies. This comparative overview serves to illustrate the molecular mechanisms of basal body formation, their similarities, and dissimilarities, in somatic versus male germ cells, by discussing the involved proteins/genes and their expression, localization, and function. The review, thus, aimed to provide a deeper knowledge of the molecular players that is essential for the expansion of clinical diagnostics and treatment of male fertility disorders.

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