Toxoplasma gondii: Reproductive parameters in experimentally infected male rats

Toxoplasma gondii is a protozoan parasite that is globally widespread and infects man and animals. With the aim of studying the influence of toxoplasmosis on male reproductive parameters, we investigated sperm motility, concentration and morphology of male rats experimentally infected by T. gondii. The GT F1 strain of T. gondii tissue cysts were fed at a dose of 5 × 10³ tissue cysts per rat by oral gavage in an experimental group of 42 healthy adult male Wistar rats, while 42 male rats were used as controls. On days 10, 20, 30, 40, 50 and 60 post-inoculation (p.i.) 7 rats from each group were anesthetized. The body weight of each animal was recorded, then epididymis and testes were immediately removed, weighed and semen evaluation was undertaken. Weight of the right epididymis was significantly decreased on day 30 p.i., sperm motility was significantly decreased on days 10, 20, 30, 40, 50 and 60 p.i. and sperm concentration was significantly decreased on days 10, 30, 40 and 60 p.i. A marked increase of sperm abnormalities was noticed on days 30 and 40 p.i. No pathological lesions were detected either in the pituitary gland or the testes. In this study it was found that toxoplasmosis can affect main reproductive parameters in male rats, which are the most predictive of their fertilizing capacity.     

Adrenal glands and testes as steroidogenic tissue are affected by retinoylation reaction

This study was undertaken to better understand the physiological role of the retinoylation process in steroidogenic tissues. In adrenal gland mitochondria, the retinoylation extent was found equal to that of testes mitochondria but without ATP in the incubation buffer. We pointed out that the endogenous mitochondrial ATP in adrenal glands is much higher than in testes, about 1.3 x 10⁻² M and 5.2 x 10⁻⁸ M, respectively. In addition, less CoASH is required for the maximal acylation activity of the retinoyl moiety to protein(s) compared to testes. The fatty acid analysis revealed a different composition of mitochondrial membranes of these two tissues. Among the different values of fatty acids, it is important to note that adrenal glands contain a much higher amount of C18:0 and a much lower amount of C22:5 ω6 and C22:6 ω3 than testes in the mitochondrial membranes. In addition, there were also differences in arachidonic acid (ARA, C20:4 ω6) content between adrenal glands and testes mitochondria. These different values in the fatty acids composition should explain the different extent of the retinoylation process between the two organs.     

锯缘青蟹精巢发育的组织学观察

组织学观察表明,锯缘青蟹（Scylla serrata)精巢发育周期可以分为精原细胞期,精母细胞期,精子细胞期,精子期和休止期5个时期。在划分精巢发育期的基础上,结合生精小管直径的成熟节段比例这2个指标,可以较准确地反映锯缘青解精巢的发育状况。而成熟节段比例可以作为锯缘青蟹精巢发育的表征指标。     

Sperm production in an extremophile fish,the cave molly (<Emphasis Type="Italic">Poecilia mexicana</Emphasis>, Poeciliidae,Teleostei)

A prominent trade-off in life history theory and evolution balances the costs of reproduction with those of basic somatic needs. Hence, reproductive efforts may be reduced in environments where additional energy is required for somatic maintenance. Here, we investigated male sperm stores in Atlantic mollies (Poecilia mexicana) from a sulfidic cave and several sulfidic and non-sulfidic surface habitats. We found significant differences among populations in the number of sperm stripped per male, which was also correlated with differences in gonad weights. The largest sperm stores were detected in males from non-sulfidic surface creeks, while males from a partially sulfidic surface system had lower sperm counts, and males from completely sulfidic systems, surface as well as subterranean, had even fewer available sperm. We conclude that the extreme environmental conditions in sulfidic habitats appear to constrain male sperm production, since hydrogen sulfide as a naturally occurring toxin requires energy-demanding adaptations. Furthermore, we examined sperm counts of lab-reared cave and surface mollies in response to energy limitation. Males from stock populations were placed under high and low food treatments for a 2-week period and then stripped of sperm. Sperm counts of surface mollies tended to be reduced by low food availability, whereas sperm counts of cave mollies did not significantly vary between food treatments, which likely points towards a higher starvation resistance in cave mollies.     

Sequestration of host plant carotenoids in the larval tissues of Helicoverpa zea

To determine the cause of the unique yellow coloration in mandibular glands of soybean-fed Helicoverpa zea larvae, the accumulation of carotenoids in various tissues of last instar larvae fed soybean, cotton and tomato foliage was quantified. Five carotenoids were detected in the foliage of all host plants but at significantly different concentrations. Xanthophylls rather than carotenes were most likely to accumulate in larval tissues. Carotenoids accumulated at different rates and some were significantly affected by larval diet. Highest levels of carotenoid accumulation, notably lutein, were detected in the testes, followed by midgut epithelium, fat body and integument. The midgut epithelium contained the greatest and the testes the least diversity of carotenoid types. Low levels of lutein were detected in both labial and mandibular glands. Tomato foliage had the highest carotenoid content and caterpillar tissues fed these leaves often had the highest amounts of carotenoid. However, the accumulation of carotenoids did not protect larvae from antibiotic effects of tomato foliage because these caterpillars had the highest mortality and slowest growth rates of all the three host plants. Transport and absorption of lipid and oxidative stress may be some reasons for differential carotenoid accumulation.     

Movement of spermatozoa in the reproductive tract of adult male Spodoptera litura: daily rhythm of sperm descent and the effect of light regime on male reproduction

Sperm production and movement from the fused testes into the male reproductive tract of the common cutworm Spodoptera litura were studied in insects maintained in a 12 h:12 h light dark (LD) regime. Two types of sperm bundles, eupyrene (nucleated) and apyrene (anucleate) were present in the adult testes. Eupyrene bundles constituted about 25% of the total. Descent of spermatozoa from the testes into the upper vas deferens (UVD) first occurred about 24-30 h before adult eclosion. On entering the reproductive tract, eupyrene spermatozoa remained in bundles while apyrene bundles became dissociated before they reached the UVD. Downward movement of both eupyrene and apyrene spermatozoa within the male tract occurred in a daily rhythm. Sperm descent from the testes into the UVD occurred during the early scotophase, followed by their further descent into the seminal vesicle (SV) during the photophase. Spermatozoa remained in the SV for only a short duration, whence sperm quickly passed through the lower vas deferens into the duplex, which acted as the main sperm storage organ until mating was initiated. During mating 80% of sperm left the duplex, but mating did not influence the number of sperm bundles that subsequently descended into the duplex or the rate of their descent. There was no evidence of sperm reflux. Rearing in constant light (LL) and in constant dark (DD) reduced the number of eupyrene sperm present in the testes of adults that emerged in LL and DD compared to controls (LD), although there was no significant effect on the number of apyrene sperm in the testes. The rhythmic pattern of sperm descent was suppressed in both LL and DD regimes, and the number of sperm in the duplex was adversely affected, with a marked impact in LL reared insects. Male longevity, mating behaviour, oviposition and fertility were found to be more severely affected in LL than in DD.     

Effects of an LHRH agonist and gonadotropins on testicular prolactin receptors

Effects of administration of the LHRH agonist D-Leu6-LHRH ethylamide (LHRH-A), gonadotropin (PMS), and their interaction on testicular prolactin (PRL) receptor levels were investigated in rats. LHRH-A (2 micrograms/100 g body wt.) or saline was injected SC daily, and PMS (5 IU) injected every other day. In intact rats, the testicular PRL receptor levels were about 400 fmoles/testis after either 1 or 7 daily injections of saline. Administration of LHRH-A decreased PRL receptors to 12% of that of saline-injected control rats at day 1, and to 20% at day 2, and PRL receptor levels were partially restored to 55% at day 7. In hypophysectomized rats given daily injections of saline for 7 days PRL receptor levels were only 20% of those in saline-injected intact rats. Injections of LHRH-A in hypophysectomized animals did not further decrease PRL receptor numbers at this time. Administration of PMS to hypophysectomized rats for 7 days partially reversed the reduction of PRL receptors that occurred after hypophysectomy, to 46% of those in intact controls. Injections of LHRH-A into hypophysectomized. PMS-treated animals did not significantly alter PRL receptors on day 1 (117% of that of saline-injected, hypophysectomized, PMS-treated rats at day 1) or day 2 (96% of same-day controls), but decreased PRL receptors on day 7 to 102 fmoles/testis (55% of same-day controls). This latter concentration is nearly the same as that in saline-injected, 7-day hypophysectomized rats not treated with PMS. These findings suggest that: (1) the effects of LHRH-A on testicular PRL receptors differ depending on the presence or absence of gonadotropin, (2) gonadotropin, primarily FSH, maintains some population of testicular PRL receptors, and these gonadotropin-dependent PRL receptors are suppressed by direct action of LHRH-A upon the testes, and (3) there is a population of PRL receptors which is not affected by LHRH-A or gonadotropin.     

Cell-free transfer of sterols from dictyosome-like structures to plasma membrane vesicles of guinea pig testes

Summary Transfer of radiolabeled lipids from dictyosome-like structures (DLS) from testis tubules of the guinea pig as donor to unlabeled plasma membrane from testis tubules immobilized on nitrocellulose as acceptor was studied in a completely cell-free system. As a general label for lipids of the donor DLS, isolated testis tubules were incubated with [¹⁴C]acetate. Time- and temperature-dependent transfer of [¹⁴C]acetate labeled constituents was observed in the cellfree system. However, despite the fact that phospholipids and other constituents were highly labeled in the donor fraction, primarily radioactive sterols were transferred to the plasma membrane acceptor vesicles. Transfer at 37°C represented 0.4 to 0.7% of the total radiolabeled cholesterol at 37°C but little or no transfer occurred at 4°C. The sterols transferred exhibited Chromatographic mobilities corresponding to those of cholesterol and lanosterol. Similar results were obtained with [¹⁴C]mevalonic acid. In subsequent experiments, cholesterol transfer from DLS to plasma membrane was demonstrated by incubation of DLS with [³H]squalene which was converted into sterol or with [¹⁴C]cholesterol. Transfer of sterols required ATP, but not cytosol, and was both time- and temperature-dependent. DLS were more effective than either endoplasmic reticulum or plasma membrane as the donor fraction. The results from the cell-free analysis suggest a possible functional role of the DLS in sterol biogenesis and transfer to the plasma membrane during spermatid development.Abbreviations DLS dictyosome-like structure(s) - PBS phosphatebuffered saline - HEPES 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid - BSA bovine serum albumin     

Sperm parameters and testicular volumes in Saguinus mystax

Adult male Saguinus mystax tamarins were evaluated for sperm parameters and testicular volumes. Sperm concentrations average 195.5 X 10(6)/cc with 41.7% motile sperm. Semen specimens were classified as normal, relative to sperm morphology, when 95% or more of the sperm in the specimen had normal morphology; 76% of the animals evaluated had normal semen specimens using this criterion. Testicular volumes averaged 726.9 mm3. A total of 50 infants were sired by 16 of these males during the period covered by this report.