Progesterone-dependent messenger RNA: heterospecific activity in vivo.

The action of progesterone in mediating the synthesis of avidin by the chick oviduct can be simulated by the intraoviductal instillation of nitrocellulose-trapped RNA from hormonally prepared chick or pigeon oviduct. Similarly, the pigeon oviduct synthesizes avidin in response to chick oviduct RNA. Thus, a heterospecific transfer of hormonal stimulation, through the transfer of progesterone-induced RNA, is demonstrated. The biological activity is lost after digestion by pancreatic ribonuclease. The 50-fold purification achieved by nitrocellulose chromatography of the total RNA preparation suggests that the activity resides in a messenger RNA fraction.

A novel icetexane diterpene, 5-epi-icetexone from Salvia gilliessi is active against Trypanosoma cruzi.

In this work the effect of a novel compound, 5-epi-icetexone (ICTX) obtained from Salvia gilliessi Benth. (Labiatae), is studied on cultured epimastigotes of Trypanosoma cruzi (Tulahuen). It was found that the compound exerts an antiproliferative effect on the parasites at concentrations between 2.8 and 4.2 microM, and similar sensitivity in other strains (Dm28c, CL-Brener and Y-strain). The compound was deleterious at concentrations higher than 4.2 microM, with an estimated IC50 of 6.5+/-0.75 microM, but with low cytotoxicity to mammalian cells. These effects were irreversible, even at short times of exposure to the drug. In solution, ICTX showed to be stable for at least 96 h at 29 degrees C. With cytostatic dose a little percentage of parasites was resistant to the action of ICTX, and they continued growing although with different kinetic. By electron transmission microscopy, at dose of 4.2 microM an external vesiculization was observed on the first day of exposure to the compound, but the parasite cytoplasm became plenty of vacuoles and exhibited nuclear disorganization from the second day of exposure. It was concluded that ICTX is active against T. cruzi and may act by multiple mechanisms. In future, this novel icetexane diterpene may be a good candidate for therapeutic use against Chagas' disease.

Surface changes of the rat embryo before implantation.

Study of the rat embryo surface under the scanning electron microscope shows the superficial structure of the pellucid membrane as a perforated network cover which does not change throughout the preimplantation period (1 to 41/2 days). Dissolution of the pellucid membrane by brief ATP treatment reveals a zygotic surface which changes from day to day. The number and length of microvilli increase with development. At the early blastula stage there is a great heterogeneity of microvilli of different size and shape as well as large membranous ruffles mainly located at one pole of the embryo. The significance of these structures may relate to the changing metabolic requirements of the developing embryo and to the invasive properties of the trophoblast.

Detection of the mouse acrosome reaction by acid phosphatase. Comparison with chlortetracycline and electron microscopy.

The sperm acrosome is a uniquely regulated secretory vesicle containing several hydrolase enzymes, including acid phosphatase (AP). The exocytotic event that releases these enzymes, the acrosome reaction, is required for fertilization in mammals. Different methods have been described in the scientific literature for detection of the acrosome reaction: double and triple stains, fluorescent-lectin stains, monoclonal antibodies against acrosomal antigens (immunodetection techniques), Coomassie blue, differential interference contrast or phase contrast, flow cytometry, and chlortetracycline (CTC). In contrast, only 1 method to detect AP released by live and reacted sperm has been described in the literature thus far. In this work we compare 2 classical methods, CTC and transmission electron microscopy (TEM), with the assay of AP released from the acrosome. AP released during the acrosome reaction was measured in the culture medium. Enzyme remaining in nonreacted sperm cells was released by Triton X-100 treatment. This enzyme-based methodology shows an increase of AP in the culture media after the acrosome reaction and a corresponding decrease in the detergent-releasable enzyme. The AP assay thus permits the detection of the mouse acrosome reaction and compares well with the CTC and TEM methods. This method is performed on the whole sperm population and so avoids the observer error that is inherent in light microscopic methods.

Evolutionary sperm morphology and morphometry in armadillos.

Little is known about the evolution of vertebrate spermatozoa. In most eutherian taxa a high degree of uniformity in sperm shapes and dimensions among species was observed. The aim of this work is to trace a possible evolutionary change in sperm morphology and morphometry in dasypodids. The main difference between the spermatozoa of the studied armadillos is the shape of the sperm heads. We have classified the spermatozoa into 4 different groups according with their head shapes. Sperm from group 1 (Dasypus) are considered ancestral and are clearly separated from the others. The remaining sperm types are derivative ones; those from group 2 (Tolypeutes) are farther from those of groups 3 (Priodontes and Cabassous) and 4 (Chaetopractus, Zaedyus and Euphractus) which would have recently differentiated from each other. The sperm shape and size are not constant across taxa in armadillos; an important evolutive differentiation was established on the sperm morphology and morphometry between the different genera in Dasypodidae.

Activation of macrophage functions by growth factor present in uterus and embryo extract of pregnant mouse.

A pregnant mouse uterus and embryo extract (PMUE) that contains growth hematopoietic factor (M-CSF or CSF-1), was used to test its action on the phagocytic and digestive functions of macrophage. Macrophages incubated with and without PMUE for 24 hours previous to each experiment were compared. A good phagocytosis of Trypanosoma cruzi by macrophages incubated with PMUE, was observed on video microscopy. No phagocytic activity was observed in the macrophages deprived of PMUE 24 hours before. The studies of phagocytic and degradative behavior of macrophages by both soluble and particulated (S. aureus) complex 125I-antibodies showed that total binding of soluble ligands was almost double in the group of macrophages incubated with PMUE. Both the soluble and particulated ligands were digested more efficiently by the macrophages stimulated by PMUE. Counting the macrophages with trypan blue, an equal viability was found, of the cells incubated with and without PMUE. From the experimental data obtained, we may conclude that the hematopoietic growth factor present in PMUE is essential for phagocytic and degradative functions of macrophages.

Immunocytochemical reaction of sera from chagasic patients against Trypanosoma cruzi, intestine of Triatoma infestans and normal human heart.

Chagas disease has been considered by some authors as an autoimmune pathology and denied by others. In this paper we present by means of immunocytochemical reactions with sera of chagasic patients, evidence in favor of the presence of similar antigens in the parasite, vector and non chagasic human heart. The immunocytochemical technique used permits the localization by electron microscopy of the antigens in the peritrophic membrane of the parasite and basement membranes of the vector's midgut and of the myosin band of the normal human heart. These observations support the assumption of an autoimmune response in Chagas disease.

Epididymal glycoprotein involved in rat sperm association.

Recently, a new head-to-head sperm association was described in the rat during epididymal transit. This association was called a rosette and a filamentous and PAS-positive material was also described joining the sperm heads. The beginning of rosette formation in the epididymis and the linking material between heads have remained unclear. Epididymides of adult rats were fixed by vascular perfusion and thin sections of the principal regions were studied by transmission electron microscopy (TEM). The first evidence of rosette formation was observed in the distal corpus. Rosettes were isolated from the distal corpus and processed for immunogold and immunofluorescence microscopy to detect an epididymal glycoprotein called DE. This glycoprotein is secreted by the corpus epididymis and appears to be involved in sperm maturation. Colloidal gold marks and fluorescence were observed in the linking material between the sperm heads. The results presented here show that rosettes begin to appear following the sites of DE secretion and permit us to postulate that DE is involved in rosette formation and constitutes another example of gamete-epididymal interaction.

The Golgi complex of the early spermatid in guinea pig.

After aldehyde-tannic fixation, Zinc-iodine-osmium fixation, Phospho Tungstic acid-chromium stain and two cytochemical reactions, the ultrastructure of the Golgi complex of early spermatids in the guinea pig reveals two different regions. One, close to the cell surface, involves endoplasmic reticulum (ER), intermediate vesicles, and Golgi outer cisternae and has membranes of uniform thickness and symmetrical trilaminar pattern, a strong ZIO precipitate, and an almost negligible cytochemical reaction to polysaccharides and cholesterol. The other region, close to the nucleus, exhibits thicker, sometimes asymmetric membranes, a polygonal network coating the thick cisterna, condensing vacuoles and areas of the acrosomal membrane, an intense reaction to polysaccharides and cholesterol, and packages of different densities in the condensing vacuoles and acrosome. This work also shows the coincidence of the cytochemical marker of cholesterol with the polygonal coating of clathrin in the condensing face of the Golgi.

The effect of LH and copulation on the number of spermatozoa in the rat testis.

In the present work we have re-examined our previous observations concerning the hormonal control of spermiation. We have applied a method which consists in the treatment of testicular homogenates by a detergent and subsequent counting of the resistant sperm heads. The results show that both LH administration and copulation are able to produce a significant diminution of the number of spermatozoa contained in the rat testis.

Tridimensional reconstruction and histology of the intratesticular seminal pathway in the hamster.

The present work reports a tridimensional reconstruction of the intratesticular seminal pathway in the hamster as studied with light microscopy of serial sections of the proximal pole of the testis. It has three portions: a "terminal segment" of the seminiferous tubules; the tubuli recti with three parts; and the rete testis with two parts, intratesticular and extratesticular. Experiments using ductuli efferentes ligation show a marked dilation of the rete testis and tubuli recti without a corresponding dilation of the seminiferous tubules. This may be due to a valve-like action of the cells in the terminal segment of the tubules.

First spermiation and spermatozoa concentration in hemicastrated rats.

Male rats ten days of age were divided in three groups: a) hemicastrated, b) sham operated and c) control. They were daily sacrificed between 30 and 50 days of age. Wet weight and dry weight were determined in testis, seminal vesicles and epididymis. The concentration of spermatozoa was measured in testis and caput epididymis. The results show a significant increase in both wet and dry weight of testis of hemicastrated animals (40.5% at 30 days of age). The total population of psermatozoa per testis is higher in hemicastrated after 48 days of age. The first arrival of spermatozoa to the caput epididymis (first spermiation) which occurs in control at 45 days of age is delayed 48 hours in the hemicastrated group, however at 50 days of age the concentration of spermatozoa in the caput is higher than in control. We related our results to the rise in plasma FSH which occurs immediately after hemicastration and involved a larger and higher exposure of the testis to FSH.

Sperm association in the rat epididymis.

During dissolution of drops obtained by puncture of rat epididymis in distal caput, mid corpus, proximal and distal cauda we observed in the last two regions the appearance of a new sperm association which we call rosette and the formation in the same two regions of dense clusters of non-motile degenerating spermatozoa already described in the rat vas deferens. Rosettes become organized in the proximal cauda by head to head sperm contact through a filamentous PAS positive material. By video microscopy was observed the dilution of a dense drop of cauda epididymal content in a balanced salt solution at 36 degrees C. In less than 3 min, rosettes become dispersed into single sperm with a display of intense motility which starts immediately after dilution. A glycoprotein with cohesive properties secreted by the epididymal epithelium is postulated as the factor promoting rosette formation. We confirm that dense clusters correspond to degenerating spermatozoa and describe its first appearance in the epididymal proximal cauda with increase in number toward vas deferens.

The surface extracellular coat of the midgut in Triatoma infestans. I. Mechanism of development.

The mechanism of formation of the apical surface, extracellular coat, and microvilli of the midgut of adult Triatoma infestans (hematophagous insect) has been studied with the electron microscope after a recent meal and after 10 days postfeeding. In the first case the extracellular coat becomes disorganized and mixed with the intestinal content. At the same time, small basal cells show the appearance of intracytoplasmic lipid droplets surrounded by a well-developed rough endoplasmic reticulum; the droplets increase in size and complexity by incorporation of other smaller droplets. Short microvilli appear at the surface of the newly formed droplets. The homogeneous dense content gradually changes due to development of delicate plexiform membranes. Fusion with similar droplets from the neighbor cells coincides with desquamation of older degenerated superficial cells and their replacement by basal cells. An extracellular coat complex emerges from the fused droplets. At 10 days postfeeding, the microvilli-coat complex attains maximal development.