Maturation Division Research Articles

Оцінка стану сперматогенезу щурів за умов моделювання радіаційного ураження та впливу препаратів природного походження

Male infertility is probably to be affected by intense heat exposure and extreme exposure to pesticides, irradiation, electromagnetic radiation and other hazardous substances. The authors of most of the works agree that the cells of the basement membrane of the tubules and spermatogonia, which are quickly exhausted after irradiation, are the most vulnerable in the testes. The type and extent of these changes depends on the dose, duration and frequency of radiation. The participation of connective tissue in almost all typical pathological conditions has been shown: inflammation, allergy, carcinogenesis, hypoxia, free radical oxidation processes, etc. The purpose of the work was to study evaluation the state of rats' spermatogenesis under conditions of the total irradiation exposure and to correct the pathological process with drugs of natural origin Chondroitin sulfate and "Bioglobin-U". Material and methods. A model of total single irradiation with a dose of 3 Gy was used to obtain the pathology of the testes, after which the substance Chondroitin sulfate was administered at a dose of 60 mg / kg; comparison drug Tribestan at a dose of 60 mg/kg; the drug "Bioglobin-U" at a dose of 200 μl / kg and Chondroitin sulfate + Tribestan in the above doses. Results and discussion. 30 days of exposure of single total irradiation with a dose of 3 Gy led to significant disruption of the morphological state of the testes and spermatogenic epithelium of rats. Thus, in rats with irradiation, the number of normal spermatogonia in the convoluted tubules was reduced by 5.7 times, there were practically no convoluted tubules with spermatocytes in the metaphase of the 2nd maturation division (with the 12th stage of meiosis) and tubules with desquamated spermatogenic epithelium, the index of spermatogenesis decreased by almost 6.5 times. The introduction of natural origin drugs led to an improvement in the quantitative and qualitative indicators of spermatogenesis. Conclusion. In the conditions of irradiation exposure, Chondroitin sulfate has more significant regenerative properties, the effect of which is almost 1.9 times better than the effect of the reference drug Tribestan. The effectiveness of "Bioglobin-U" in these experimental conditions was somewhat inferior to Chondroitin sulfate, but this drug was almost 1.4 times more effective than the reference drug Tribestan. The combination of Tribestan and the substance Chondroitin sulfate was more than 1.4 times more effective than the reference drug Tribestan itself

Polymorphisms within the Boule Gene Detected by Tetra-Primer Amplification Refractory Mutation System PCR (T-ARMS-PCR) are Significantly Associated with Goat Litter Size.

Simple SummaryMutations of the Boule gene, a gene that contributes to spermatogenesis, are a main cause of mammal infertility in reproduction. As a conserved gene, only some single nucleotide polymorphisms (SNPs) in the introns within it have been reported in humans with meiosis block, but not in goats, and especially its fundamental roles in female reproduction are still unknown. Therefore, this study detected the potential polymorphisms of the Boule gene in goats via the tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR). Herein, one predicted SNP locus (rs661484476: g.7254T>C) of the Boule gene was first detected and displayed moderate polymorphism among all the studied groups. Notably, the polymorphisms of the goat Boule gene were significantly associated with the goat litter size in different groups, and female goats with the heterozygous genotype (CT) had more possibilities to produce multiple lambs than others, indicating that the Boule gene might underlie female reproductive capacities and that g.7254T>C could be a potential marker in the marker-assisted selection process for litter size in goats.As a gene contributing to spermatogenesis, the Boule gene (also called Boll), whose mutations result in azoospermia and sterility of flies and mice, was conserved in reductional maturation divisions. However, in goats, the polymorphisms of Boule, especially with regard to their fundamental roles in female reproduction traits, are still unknown. Therefore, the aims of this study were to detect a potential mutation (rs661484476: g.7254T>C) located in intron 2 of the Boule gene by tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR) and to explore its potential association with the litter size of Shaanbei White-Cashmere goats (SBWGs). In this study, g.7254T>C was firstly detected. The TT genotype was the dominant genotype in the single-lamb group, and T was also the dominant allele in all tested groups. Additionally, the detected locus displayed moderate polymorphism with polymorphism information content (PIC) values among all studied goats ranging from 0.303 to 0.344. Notably, according to the χ2 test, the distribution differences for the genotypic frequencies between the single- and multi-lamb groups was significant (p = 0.014). Furthermore, the polymorphisms of the goat Boule gene were significantly associated with the goat litter size in SBWGs (p < 0.05), which indicated that g.7254T>C could be a potential marker in the marker-assisted selection process for potential litter size in goats. These results also indicated that the Boule gene might exercise important functions in female goat reproduction, which provided new insight for female goat breeding and could accelerate the process of goat breeding.

A huge diversity of metopids (Ciliophora, Armophorea) in soil from the Murray River floodplain, Australia. III. Morphology, ontogenesis and conjugation of Metopus boletus nov. spec., with implications for the phylogeny of the SAL supercluster

The morphology, ontogenesis, conjugation, and phylogenetic position of Metopus boletus nov. spec. were studied using live observation, various silver impregnation methods, scanning electron microscopy, morphometry, and the 18S rRNA gene sequence. The new species is outstanding in having a mushroom-like appearance; a globular to broadly ellipsoid macronucleus in anterior body half; 5–10 elongated caudal cilia; 4–6 dikinetids curved rightwards in the anterior portion of the first postoral kinety; and an adoral zone composed of an average of 28 small polykinetids. Ontogenesis of M. boletus follows the metopid mode and the species-specific vegetative morphology is obtained after division. Its conjugation is temporary, isogamic and the partners unite ventral-to-dorsal, forming strongly arched to almost rod-like pairs, which indicates a heteropolar arrangement. There are only two maturation divisions and a single synkaryon division in exconjugants. The conjugation data corroborate a sister group relationship of the classes Armophorea and Litostomatea within the SAL (Spirotrichea + Armophorea + Litostomatea) supercluster in that the partners unite ventral-to-dorsal and the main body axes are antiparallel. On the other hand, the last common ancestor of the spirotricheans very likely had a ventral-to-ventral and homopolar conjugation mode with the main body axes oriented in parallel.

Embryonic expression of festina lente (fel), a novel maternal gene, in the oligochaete annelid Tubifex tubifex

We have cloned and characterized the expression of a novel maternal gene festina lente (designated Ttu-fel) from the clitellate annelid Tubifex tubifex. Northern blot analyses have shown that Ttu-fel mRNA is approximately 8 kbp in length and that its expression is restricted to oocytes undergoing maturation division and early embryos up to 22-cell stage. Maternal transcripts of Ttu-fel are first detected in oocytes in the ovary of young adults (ca. 40 days after hatching); its expression continues in growing oocytes in the ovisac. Ttu-fel mRNA is distributed broadly throughout the egg undergoing maturation divisions. During the process of ooplasmic segregation that results in the pole plasm formation, Ttu-fel mRNA becomes concentrated to the animal and vegetal poles. The RNA in the animal hemisphere is distributed in a gradient with highest concentration in the cortical region. During the first two cleavages, Ttu-fel mRNA is segregated to CD cell then to D cell; it is subsequently inherited by the three D quadtrant micromeres, 1d, 2d and 3d. Around the time of transition to 22-cell stage, Ttu-fel mRNA becomes undetectable throughout the embryo.

Ultrastructural Studies of Germ Cell Development and the Functions of Leydig Cells and Sertoli Cells associated with Spermatogenesis in Kareius bicoloratus (Teleostei, Pleuronectiformes, Pleuronectidae).

The ultrastructures of germ cells and the functions of Leydig cells and Sertoli cells during spermatogenesis inmale Kareius bicoloratus (Pleuronectidae) were investigated by electron microscope observation. Each of the well-developed Leydig cells during active maturation division and before spermiation contained an ovoid vesicular nucleus, a number of smooth endoplasmic reticula, well-developed tubular or vesicular mitochondrial cristae, and several lipid droplets in the cytoplasm. It is assumed that Leydig cells are typical steroidogenic cells showing cytological characteristics associated with male steroidogenesis. No cyclic structural changes in the Leydig cells were observed through the year. However, although no clear evidence of steroidogenesis or of any transfer of nutrients from the Sertoli cells to spermatogenic cells was observed, cyclic structural changes in the Sertoli cells were observed over the year. During the period of undischarged germ cell degeneration after spermiation, the Sertoli cells evidenced a lysosomal system associated with phagocytic function in the seminiferous lobules. In this study, the Sertoli cells function in phagocytosis and the resorption of products originating from degenerating spermatids and spermatozoa after spermiation. The spermatozoon lacks an acrosome, as have been shown in all teleost fish spermatozoa. The flagellum or sperm tail of this species evidences the typical 9+2 array of microtubules.

Prediction of embryonic development and clinical outcome following ICSI according to the stages of nuclear maturation division

Pre-ovulatory oocytes collected after controlled ovarian stimulation are considered mature with the extrusion of the first polar body at ICSI. However embryonic development varies following ICSI for morphologically mature oocytes. We conducted this study to investigate whether it is possible to predict embryonic development and clinical outcome according to the stages of nuclear maturation division.

Varicocele-Induced Infertility in Animal Models.

Varicocele is characterized by abnormal tortuosity and dilation of the veins of the pampiniform plexus within the spermatic cord. Although several reports show the mechanisms by which the varicocele exerts its infertility impact, the exact pathophysiology for varicocele-induced inflammation and its relationship with testicular endocrine disruption remain largely unknown. This review article will update previous findings by discussing the pathophysiology of long term-induced varicocele in rats. Testicular endocrine disruption in experimentally-induced varicocele, new findings related to biochemical alterations in germinal epithelium, and sperm cells apoptosis are highlighted. Recent observations show that varicocele down-regulates first and second maturation divisions, results in Leydig and Sertoli cell inflammation, and increases immune cell infiltration in the testes of the rat as an animal model. Ultimately, previous findings of our laboratory have revealed that varicocele decreased sperm motility, viability and severe DNA damage. Damage in sperm significantly lowers the animal's fertility potential. Varicocele not only exerts its pathologic impact by lowering the testicular antioxidant capacity but it also down-regulates first and second maturation divisions by exerting biochemical alterations such as reducing the intracytoplasmic carbohydrate ratio in germinal epithelium.

The boule gene is essential for spermatogenesis of haploid insect male

boule (bol), a member of the Deleted in Azoospermia (DAZ) gene family plays an important role in meiosis (reductional maturation divisions) in a spermatogenesis-specific manner in animals by regulating translation of the downstream cell division cycle 25 (cdc25) phosphatase mRNA. Orthologues of bol are conserved among animals and found in the genomes of hymenopteran insects, in which the general mode of reproduction is haplodiploidy: female is diploid and male is haploid. In this mode of reproduction, haploid males produce haploid sperm through non-reductional maturation divisions. The question thus arises of whether the bol gene actually functions during spermatogenesis in these haploid males. In this study, we identified two transcriptional isoforms of bol orthologue (Ar bol and Ar bol-2), and one cdc25 orthologue (Ar cdc25) in the hymenopteran sawfly, Athalia rosae. Ar bol was expressed exclusively in the testis when maturation divisions occurred, while Ar bol-2 was expressed ubiquitously. Knockdown of all bol transcripts (both Ar bol and Ar bol-2) resulted in a lack of mature sperm, whereas males with sole knockdown of Ar bol-2 were able to produce a small number of mature sperm. The cell cycle was arrested before maturation divisions in the testis in which all bol transcripts were knocked down, as revealed by flow cytometry. Although no mature sperm was produced, sperm elongation was partially observed when Ar cdc25 alone was knocked down. These results indicate that Ar bol is essential for the entry and progression of maturation divisions and sperm differentiation in haploid males.

Prediction of embryonic development and clinical outcome following ICSI according to the stages of nuclear maturation division

Pre-ovulatory oocytes collected after controlled ovarian stimulation are considered mature with the extrusion of the first polar body at ICSI. However embryonic development varies following ICSI for morphologically mature oocytes. We conducted this study to investigate whether it is possible to predict embryonic development and clinical outcome according to the stages of nuclear maturation division.

Development of the swimming acorn worm Glandiceps hacksi: similarity to holothuroids

Spawnings of Glandiceps hacksi (Hemichordata: Enteropneusta) were stimulated in the laboratory by a brief increase in temperature, and the development from fertilization through metamorphosis is described for the first time for a member of the family Spengelidae. When fertilized, the spawned female gametes, which are primary oocytes, rapidly raise a fertilization membrane and undergo two maturation divisions. Holoblastic, radial cleavage produces a blastula; a gastrula then forms by invagination from the vegetal pole, and the blastopore closes soon thereafter. In previously described enteropneust embryos, the archenteron buds off the protocoel before the latter connects to the exterior via the proboscis pore. By contrast, in G. hacksi the archenteron precociously connects with the exterior before the protocoel forms. Soon thereafter, the embryo becomes uniformly ciliated and then hatches from the fertilization envelope at approximately 32 h (15°C culture temperature). At day 3 of development, the protocoel separates from the gut, which establishes a mouth opening to the exterior; by this time, the gut has differentiated into an esophagus, a stomach, and an intestine that opens posteriorly as an anus. The larva grows to form a tornaria with distinctive pigment patches along its ciliary bands.

Apomictic parthenogenesis in a parasitoid waspMeteorus pulchricornis, uncommon in the haplodiploid order Hymenoptera

Although apomixis is the most common form of parthenogenesis in diplodiploid arthropods, it is uncommon in the haplodiploid insect order Hymenoptera. We found a new type of spontaneous apomixis in the Hymenoptera, completely lacking meiosis and the expulsion of polar bodies in egg maturation division, on the thelytokous strain of a parasitoid wasp Meteorus pulchricornis (Wesmael) (Braconidae, Euphorinae) on pest lepidopteran larvae Spodoptera litura (Fabricius) (Noctuidae). The absence of the meiotic process was consistent with a non-segregation pattern in the offspring of heterozygous females, and no positive evidence was obtained for the induction of thelytoky by any bacterial symbionts. We discuss the conditions that enable the occurrence of such rare cases of apomictic thelytoky in the Hymenoptera, suggesting the significance of fixed heterosis caused by hybridization or polyploidization, symbiosis with bacterial agents, and occasional sex. Our finding will encourage further genetic studies on parasitoid wasps to use asexual lines more wisely for biological control.

La Theorie de la Chiasmatypie

Abstract First published in 1909 in La Cellule, F. A. Janssens’s “The chiasmatype theory. A new interpretation of the maturation divisions” proved controversial and was for several decades resisted by many geneticists and cytologists. In this month’s Perspectives, Koszul et al. revisit Janssens's findings and the surrounding controversies. Here, translated for the first time in English, GENETICS republishes the original Janssens’s article. The article is presented as closely as possible to the original publication’s format and style.2 GENETICS wishes to thank Romain Koszul and Denise Zickler for their labors in presenting the scientific community with this new translation.

RFamide-Related Peptide and Messenger Ribonucleic Acid Expression in Mammalian Testis: Association with the Spermatogenic Cycle

RFamide-related peptide (RFRP), the mammalian homolog of avian gonadotropin-inhibitory hormone, has a pronounced suppressive action on the reproductive axis across species. In mammals, RFRP acts directly on GnRH neurons, and likely at the level of the pituitary, to inhibit gonadotropin secretion. In the present study, we examined whether RFRP might act outside of mammalian brain on reproductive tissues directly. Using RT-PCR and in situ hybridization, we found that both RFRP and its receptors [G protein-coupled receptor (GPR) 147 and GPR74] are expressed in the testis of Syrian hamster. These results were confirmed and extended using double- and triple-label immunohistochemistry. RFRP expression was observed in spermatocytes and in round to early elongated spermatids. Significant expression of RFRP was not seen in Leydig cells. GPR147 protein was observed in myoid cells in all stages of spermatogenesis, pachytene spermatocytes, maturation division spermatocytes, and in round and late elongated spermatids. GPR74 proteins only appeared in late elongated spermatids. Additionally, we found that RFRP and its receptor mRNA are markedly altered by day length and reproductive condition. These findings highlight a possible novel autocrine and/or paracrine role for RFRP in Syrian hamster testis, potentially contributing to the differentiation of spermatids during spermiogenesis.

Automictic parthenogenesis of a geographically parthenogenetic mayfly, Ephoron shigae (Insecta: Ephemeroptera, Polymitarcyidae)

In the geographically parthenogenetic mayfly, Ephoron shigae, egg maturation and counts of chromosome number of unfertilized, parthenogenetic eggs were studied, in comparison with fertilized eggs from a bisexual population. The primary oocyte becomes mature through two successive maturation divisions. The first maturation division (meiotic division) takes place in the primary oocyte to produce a secondary oocyte and a first polar body. The second maturation division soon occurs in the secondary oocyte, in which the nucleus is divided into a mature egg nucleus (female pronucleus) and second polar body nuclei. The first polar body, in some cases, was successively divided into two polar bodies; in other instances, it was not divided. After the successive maturation division, the egg nucleus and the sister second polar body nucleus drew near to fuse into the zygote nucleus. The chromosome number was doubled in the zygote, and this conjugation initiates subsequent embryonic development. This suggests that, in E. shigae, the process of parthenogenetic recovery of diploidy is the automictic type categorized as the ‘terminal fusion’ pattern. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 335–343.

256 ROLE OFTHE BOVINE OOCYTE-SPECIFIC PROTEIN JY-1 IN REGULATION OF MESSENGER RNA ABUNDANCE FOR GENES LINKED TO CUMULUS EXPANSION

We have previously demonstrated a requirement of the oocyte-specific protein JY-1 for oocyte and early embryonic development in cattle. Microin- jection of JY-1 siRNA into cumulus-enclosed germinal vesicle-stage oocytes impedes progression to metaphase II and cumulus expansion during in vitro maturation and limits subsequent embryonic development following in vitro fertilization. Negative effects of siRNA-mediated reduction in JY-1 on oocyte maturation, cumulus expansion, and initial cleavage divisions following in vitro fertilization can be rescued bysupplementation with recom- binant JY-1 protein during oocyte culture. However, the mechanisms involved in JY-1 regulation of above developmental endpoints are unknown. The objective of the current study was to determine whether JY-1-induced regulation of cumulus expansion during meiotic maturation is linked to alterations in mRNA abundance for genes that promote formation and stabilization of the mucified extracellular matrix characteristic of an expanded cumulus layer. Cumulus-enclosed germinal vesicle stage-bovine oocytes were microinjected with JY-1 siRNA, subjected to negative control siRNA microinjection or served as uninjected controls (n = 10 oocytes/treatment; n = 5 replicates), and cultured for 48 h in maturation medium containing 50 μM S-roscovitine to block spontaneous germinal vesicle breakdown. Cumulus-oocyte complexes were then washed and in vitro matured for an additional 24 h in maturation medium minus S-roscovitine. Additional JY-1 siRNA injected and uninjected cumulus-enclosed oocytes were cultured as described earlier but in the presence of 1 ng/mL of recombinant JY-1 protein (n = 10 oocytes/treatment; n = 5 replicates). Dose of recombinant JY-1 protein utilized was previously shown to reverse inhibitory effects of JY-1 siRNA injection on cumulus expansion. After in vitro maturation, cumulus cells were harvested and RNA isolated and subjected to reverse transcription. Real-time PCR analysis was then conducted to determine the effect of treatments on cumulus-cell mRNA abundance for HAS2, HAS3, PTX3, and TNFAIP6. Effects of JY-1 supplementation or depletion (siRNA injection) on cumulus-cell mRNA abundance for HAS2 and HAS3 (enzymes involved in hyaluronan synthesis) were not observed. However, abundance of mRNA for TNFAIP6 and PTX3 (molecules implicated in stabilization of the hyaluronan-rich extracellular matrix) was reduced (relative to uninjected and negative control siRNA groups) in response to JY-1 siRNA injection (P &lt; 0.05) and effects of JY-1 siRNA were rescued by JY-1 protein treatment (P &lt; 0.05). Effects of JY-1 protein supplementation on cumulus-cell TNFAIP6 and PTX3 mRNA in uninjected controls were not observed. Results support a requirement of the oocyte-specific protein JY-1 for regulation of expression of genes functionally linked to stabilization of the hyaluronan-rich extracellular matrix and cumulus expansion. This research was supported by USDA 2008-35203-19094 to G. W. Smith.

Reducing CYP51 inhibits follicle-stimulating hormone induced resumption of mouse oocyte meiosis in vitro

Meiosis activating sterol, produced directly by lanosterol 14-alpha-demethylase (CYP51) during cholesterol biosynthesis, has been shown to promote the initiation of oocyte meiosis. However, the physiological significance of CYP51 action on oocyte meiosis in response to gonadotrophins' induction remained to be further explored. Herein, we analyzed the role of CYP51 in gonadotrophin-induced in vitro oocyte maturation via RNA interference (RNAi). We showed that although both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) significantly induced meiotic resumption in follicle-enclosed oocytes (FEOs), the effect of LH on oocyte meiosis resumption in FEOs was weaker than FSH. Moreover, both FSH and LH were able to upregulate CYP51 expression in cultured follicular granulosa cells when examined at 8 h or 12 h posttreatments, respectively. Interestingly, whereas knockdown of CYP51 expression via small interference RNA (siRNA) moderately blocked (23% reduction at 24 h) FSH-induced oocyte maturation [43% germinal vesicle breakdown (GVBD) rate in RNAi vs. 66% in control, P < 0.05] in FEOs, similar treatments showed no apparent effects on LH-induced FEO meiotic maturation (58% GVBD rate in RNAi vs. 63% in control, P > 0.05). Moreover, the results in a cumulus-enclosed oocytes (CEOs) model showed that approximately 30% of FSH-induced CEOs' meiotic resumption was blocked upon CYP51 knockdown by siRNAs. These findings suggest that FSH, partially at least, employs CYP51, and therefore the MAS pathway, to initiate oocyte meiosis.

Kinetics of the Enzymatic Pattern in the Testis

The "morphology" of the enzymatic activities of thiamine pyrophosphatase (TPPase), acid phosphatases (ACPases), adenosine triphosphatase (ATPase) and steroid-3 beta-ol dehydrogenase (St-3 beta-ol DH) has been described using as a basis the classification of the seminiferous epithelium of the rat into 14 stages as proposed by Leblond and Clermont (1952a, b). It was demonstrated (Figs. 1, 2) that 1. the kinetics of the enzymatic pattern is correlated with the developmental stages during spermatocyto- and spermiogenesis, and that therefore the chemocytostructure, especially of the germ cells, shows characteristic changes. 2. the enzymatic pattern yields information on the chemohistostructure of the testis, and thus indicates interactions between the germ cells and the coordinated somatic cells. This is valid especially for the behaviour of the "marker enzymes" TPPase and ACPases. Initially the activity of both enzymes is distributed in the cytoplasm: TPPase appears in stage VII in the preleptotene spermatocytes, and ACPases appear in stage VII in the pachytene spermatocytes. In the following stages the activity of TPPase and ACPases increases and becomes more and more concentrated, i.e. from stage IX to XIV and thereafter from stage I to XIII in the case of TPPase, and from stage I to XIII in the case of ACPases. Finally the enzymatic activity of both TPPase and ACPases is arranged in spherical bodies near the nucleus of the spermatocytes. Thus the late pachytene and diplotene spermatocytes, as well as the spermatocytes in diakinesis, are characterized by deeply stained spherical dots covering the region of the Golgi apparatus. Both enzymes disappear during the maturation divisions--parts of the cytoplasm of the II-spermatocytes during interphase react weakly positive--, reappear in the Golgi region of the newly formed spermatids in stage I, remain there up to stage V in the case of ACPases, and up to stage VII in the case of TPPase. From stages VIII to XIV TPPase is weakly positive in the Golgi apparatus of the elongating spermatids, moving within the cytoplasm from the head region towards the tail. Finally they appear in the cytoplasm of the Sertoli cells: (1) ACPases appear in the borderline region between the Sertoli cells and the elongated spermatids in stages XII to XIV (2) TPPase first appears in the basal region of the Sertoli cells in stages XI to XIV, and becomes positive in the subsequent stages I to IV as "streamer like" bands from the basement membrane up to the heads of the elongated spermatids. Both enzymes disappear gradually during stages I to III and IV to V respectively. Stage dependence of ATPase can be observed in the apical region of the Sertoli cells around the heads and the middle pieces of the elongated spermatids. ATPase appears for the first time in stages IX to X, and becomes increasingly more and more concentrated and condensed up to the point when the newly formed spermatozoa are released in stage VIII...

Influence of an Aromatase Inhibitor (4-Acetoxy-4-Androstene-3,17-Dione) on Experimentally Induced Impairment of Spermatogenesis in Immature Rats/Einfluß eines Aromatasehemmers (4-Acetoxy-4-Androsten-3,17-dion) auf die experimentell induzierte Hemmung der

Subcutaneous treatment of immature male rats with an estrogen precursor, 19-hydroxy-testosterone (19-OHT), at a daily dose of 1 mg/animal for 14 days leads to a significant decrease in the weight of testis, ventral prostate and seminal vesicle. The peripheral levels of LH are lowered. Testicular histology indicates that the effects of 19-OHT are very similar to the known of effect induced by estradiol-17 beta. 19OHT induces a marked impairment of spermato- and spermiogenesis. The maturation division is completely inhibited. The effect of 19-OHT on spermatogenesis is partially reversed by concomitant administration of an aromatase inhibitor (4-acetoxy-4-androstene-3.17-dione, (4-AA] at a dose of 1 mg/animal/day s.c. Meiotic activity is restored, and the weights of genital organs and the serum LH values increase. 4-AA alone has no appreciable effect on the parameters examined in this study. The present results suggest that specific inhibitors of estrogen biosynthesis might not only be useful to investigate the patho-physiological role of estrogens on spermatogenesis, but also be suitable to some extent for the treatment of estrogen-induced infertility in men suffering from idiopathic oligozoospermia.

Conjugation in the spirotrich ciliate Halteria grandinella (Müller, 1773) Dujardin, 1841 (Protozoa, Ciliophora) and its phylogenetic implications

The conjugation of Halteria grandinella was studied in protargol preparations. The isogamontic conjugants fuse partially with their ventral sides to a homopolar pair. The first maturation division generates dramatic transformations: (i) the partners obtain an interlocking arrangement; (ii) the number of bristle kineties decreases from seven to four in each partner; and (iii) the right conjugant loses its buccal membranelles, the left the whole adoral zone. The remaining collar membranelles arrange around the pair's anterior end and are shared by both partners; finally, the couple resembles a vegetative specimen in size and outline. The vegetative macronucleus fragments before pycnosis. The micronucleus performs three maturation divisions, but only one derivative each performs the second and third division. The synkaryon divides twice, producing a micronucleus, a macronucleus anlage, and two disintegrating derivatives. Scattered somatic kinetids occur during conjugation, but disappear without reorganization. An incomplete oral primordium originates in both partners. The conjugation of Halteria grandinella resembles in several respects that of hypotrich spirotrichs; however, the majority of morphological, ontogenetical, and ultrastructural features still indicates an affiliation with the oligotrich and choreotrich spirotrichs. Accordingly, the cladistic analysis still contradicts the genealogy based on the sequences of the small subunit rRNA gene.

Developmental potential of selectively enucleated immature mouse oocytes upon nuclear transfer

Selective enucleation (SE) was applied to germinal vesicle (GV) oocytes by removing the chromatin attached to nuclear envelope, and leaving the liquid contents of GV in the cytoplast. However, after reconstruction with 1/8 blastomeres or fetal fibroblasts (FFs) neither the maturation efficiency nor the frequency of normal (asymmetric) division was improved as compared with completely enucleated (CE) oocytes. Chromosomal aberrations introduced with somatic nuclei were not rescued in SE oocytes either. On the other hand, timing of maturation division in SE GV oocytes, but not in CE GV oocytes, reconstructed with GV-karyoplasts was like in the control. After maturation and fertilization in vitro, SE oocytes reconstructed with 1/8 blastomeres developed nucleolated donor pronuclei, contrary to CE oocytes. The latter could be rescued with nucleoli-containing nucleus, but not anucleolate nucleus, from a 1/2 blastomere. SE oocytes reconstructed with FFs contained nucleolated pronuclei upon activation, unlike CE GV oocytes. These experiments show that the ooplast nucleolar material and/or embryonic nucleolus are indispensable for pronuclei formation. SE oocytes reconstructed with 1/8 blastomeres or FFs failed to cleave after activation or in vitro fertilization. Control GV oocytes enucleolated before fertilization seized cleavage at the 6-cell stage, as oppose to intact GV oocytes, which in 50.9% yielded morulae/blastocysts. These results suggest that ooplast nucleolar material is essential for the cleavage divisions. Activation of cumulus-enclosed SE GV oocytes matured in hormone-supplemented medium and fused to 1/2 blastomere-karyoplasts, yielded morulae, and blastocysts in 45.5% and 23.4% of reconstructed oocytes, respectively.