Histochemistry of implantation in the rabbit

Summary The distribution of glycogen, acid and neutral mucopolysaccharides, hydrolases alkaline phosphatases, and carbohydrate dehydrogenases is described in the rabbit blastocyst and its surroundings over the implantation period from 5 to 9 days.Glycogen is found mainly in the embryonic tissues, where peaks of concentration coincide with differentiation, some is also seen in the uterine epithelium and secretion, and large quantities accumulate in the developing decidua.Neutral mucopolysaccharide is found in the yolk-sac and embryonic endoderm, and as secretion droplets in the uterine epithelium and secretion.Acid mucopolysaccharide occurs in the embryonic coverings and uterine secretion.RNA is associated in the embryo with developing tissues, and accumulates in the developing decidual cells.Hydrolases (acid phosphatase, and B esterase) increase their activity in the trophoblast knobs, in developing syncytiotrophoblast, and in the embryonic endoderm. Degeneration of the uterine epithelium is associated with maximal hydrolase activity.Trophoblastic alkaline phosphatase activity (non-specific and specific) decreases from 5 to 7 days of gestation, then increases markedly in the developing syncytiotrophoblast. AMPase appears in the embryonic mesoderm. In the uterine epithelium intense brush border staining is seen, and TPPase and UDPase become visible for a short period in the Golgi region. Phosphatases increase their activity in the decidua to 8 days and then decrease.Carbohydrate dehydrogenases (except -glycero-phosphate and -hydroxy-butyrate dehydrogenases) increase their activity in embryonic tissues, particularly in the developing syncytiotrophoblast and endoderm. Symplasma formation in the uterine epithelium is also associated with increase in enzyme activity, and a similar increase, up to 8 days of gestation, is seen in the decidua with isocitrate, malate, glucose-6-phosphate, lactate, succinate, and furfuryl alcohol dehydrogenases.Some correlation is found between the histochemical findings and the phenomena of epithelial removal, uterine secretion, decidual formation and function, giant cell function, morphogenesis, and histiotrophic nutrition, and the results are compared with previous findings for the rat in which implantation is morphologically, and probably physiologically a very different process.     

Comparative histochemical distribution of “leucine amino-peptidase” in the placenta and foetal membranes

Summary The distribution of an enzyme, or enzymes hydrolysing l-leucyl--naphthylamide is studied in the placentae, foetal membranes, and uterine structures of the horse, sheep, cat, dog, ferret, rat, rabbit, guinea-pig, and human. Activity is seen mainly in the trophoblast (except that of the cat, dog, and guinea-pig), in the rodent yolk-sac endoderm (except that of the rat), or in the uterine epithelium — surface (sheep and guinea-pig) or glandular (dog). The presence of the enzyme or enzymes is correlated with possible functions in absorption and transport of materials, or in elaboration and release of complex molecules.     

Organization of centromeres in the decondensed nuclei of mature human sperm

The localization of centromeres in mature human sperm was shown by immunofluorescent labeling and nonisotopic in situ hybridization. In the decondensed nucleus structural elements (dimers, tetramers, linear arrays and V shape structures) formed by individual centromeres of nonhomologous chromosomes were observed. They organize the compact chromocenter, which was shown for nuclei decondensed to a low extent. The chromocenter is buried inside the nucleus; in contrast, telomeric regions of chromosomes were tentatively localized on the periphery. Thus, a gross architecture, which can influence selective unpackaging of the paternal genome upon fertilization, exists in human sperm.     

Comparison of the Molecular Forms of the Kex2/Subtilisin-Like Serine Proteases SPC2, SPC3, and Furin in Neuroendocrine Secretory Vesicles Reveals Differences in Carboxyl-Terminus Truncation and Membrane Association

Abstract: The molecular forms and membrane association of SPC2, SPC3, and furin were investigated in neuroendocrine secretory vesicles from the anterior, intermediate, and neural lobes of bovine pituitary and bovine adrenal medulla. The major immunoreactive form of SPC2 was the full-length enzyme with a molecular mass of 64 kDa. The major immunoreactive form of SPC3 was truncated at the carboxyl terminus and had a molecular mass of 64 kDa. Full-length 86-kDa SPC3 with an intact carboxyl terminus was found only in bovine chromaffin granules. Immunoreactive furin was also detected in secretory vesicles. The molecular masses of 80 and 76 kDa were consistent with carboxyl-terminal truncation of furin to remove the transmembrane domain. All three enzymes were distributed between the soluble and membrane fractions of secretory vesicles although the degree of membrane association was tissue specific and, in the case of SPC3, dependent on the molecular form of the enzyme. Significant amounts of membrane-associated and soluble forms of SPC2, SPC3, and furin were found in pituitary secretory vesicles, whereas the majority of the immunoreactivity in chromaffin granules was membrane associated. More detailed analyses of chromaffin granule membranes revealed that 86-kDa SPC3 was more tightly associated with the membrane fraction than the carboxyl terminus-truncated 64-kDa form.     

The VirB4 ATPase of Agrobacterium tumefaciens is a cytoplasmic membrane protein exposed at the periplasmic surface.

The VirB4 ATPase of Agrobacterium tumefaciens, a putative component of the T-complex transport apparatus, associates with the cytoplasmic membrane independently of other products of the Ti plasmid. VirB4 was resistant to extraction from membranes of wild-type strain A348 or a Ti-plasmidless strain expressing virB4 from an IncP replicon. To evaluate the membrane topology of VirB4, a nested deletion method was used to generate a high frequency of random fusions between virB4 and 'phoA, which encodes a periplasmically active alkaline phosphatase (AP) deleted of its signal sequence. VirB4::PhoA hybrid proteins exhibiting AP activity in Escherichia coli and A. tumefaciens had junction sites that mapped to two regions, between residues 58 and 84 (region 1) and between residues 450 and 514 (region 2). Conversely, VirB4::beta-galactosidase hybrid proteins with junction sites mapping to regions 1 and 2 exhibited low beta-galactosidase activities and hybrid proteins with junction sites elsewhere exhibited high beta-galactosidase activities. Enzymatically active VirB5::PhoA hybrid proteins had junction sites that were distributed throughout the length of the protein. Proteinase K treatment of A. tumefaciens spheroplasts resulted in the disappearance of the 87-kDa VirB4 protein and the concomitant appearance of two immunoreactive species of approximately 35 and approximately 45 kDa. Taken together, our data support a model in which VirB4 is topologically configured as an integral cytoplasmic membrane protein with two periplasmic domains.     

Tolerance and cross tolerance with morphine resulting from physiological release of endogenous opiates

Mice which had been exposed to a chronic schedule of warm water swimming showed the development of a significant tolerance to the antinociceptive response (tail-flick latency) and a significant, two-fold increase in the ED50 of morphine (tail-flick latency and abdominal constriction response). These results suggest the involvement of endogenous opiates during swim stress in mice and are consistent with the hypothesis that during chronic stress the opiate receptors are activated in a manner analogous to the repeated application of exogenous opiates producing tolerance, morphine cross tolerance and (as previously reported) withdrawal-like behaviour.     

Physical dependence on physiologically released endogenous opiates

Mice which had been submitted to a chronic schedule of warm water swimming exhibited a naloxone precipiated withdrawal behaviour which was remarkably similar to that produced in mice following chronic morphine treatment. These results are consistent with the activation of endogenous opiates during swim stress in mice and present the possibility that opiate receptors are activated in a manner analogous to the repeated application of exogenous opiates, producing both tolerance and withdrawal-like behaviour.