Inhibition of in vitro fertilization by mouse anti-mouse sperm sera and preliminary antigen identification

Antisperm antibodies are implicated as one causative factor of infertility, but the target antigens have not been identified. Immune responses to sperm antigens are qualitatively variable even within a single mouse strain. We took advantage of this variability and immunized individual female mice to allogeneic sperm to reflect their natural exposure during mating. We determined the ability of the individual sera to inhibit in vitro fertilization and to bind to sperm antigens separated by electrophoresis. Compared to preimmune sera, four of five immune sera significantly inhibited in vitro fertilization. The serum from individual mice bound variable panels of sperm antigens. By comparing the panels, we identified two polypeptides with molecular weights of 40,000 and 44,000 that were bound by all sera. We propose that these molecules may be good candidates for further investigation of the immunoprophylaxis of pregnancy.     

Effects of synaptic Activity on the metabolism and release of purines in the rat superior cervical ganglion

The release of radioactive metabolites from isolated rat superior cervical ganglia was measured under various conditions following preloading with 3H-adenosine. The 3H label was recovered primarily in the adenosine metabolites, ATP, ADP, AMP, IMP, and inosine, rather than in adenosine itself. Increased release was evoked by preganglionic stimulation or by exposure to a high-K+ medium, whereas in a low-Ca2+-high-Mg2+ medium, both spontaneous release and evoked release of most metabolites were inhibited. Exposure of the ganglion to an atmosphere of N2 also increased the release of most labeled metabolites, but this release was not substantially affected by a low-Ca2+ medium. The fluorescent derivatives of the endogenous adenine-containing compounds present in the ganglion were prepared from homogenates and separated by high-performance liquid chromatography (HPLC). By the end of the testing period (6 hr), levels of ATP in the isolated ganglia had dropped to 10-20% of the initial values, while levels of ADP, AMP, and adenosine increased. There was little difference in these values between nonstimulated ganglia and those exposed to N2 or to a high-K+ medium.     

Genetic characterization of mouse immunoglobulin allotypic determinants (allotopes) defined by monoclonal antibodies

We have generated a new series of monoclonal antibodies recognizing allotypic determinants on mouse IgG₁, IgG_2a, and IgG_2b. In this communication we describe their reactivities with immunoglobulins of the inbred mouse strains. Comparison with serology charts indicates that many of these monoclonal antibodies detect allotypic specificities previously defined by conventional antisera; others define previously undescribed specificities. Strain and isotype distribution allows us to assign five new allotypic specificities to Igh-1 and three new specificities to Igh-3. In addition, on the basis of reactivity with the monoclonal antibodies, we have defined a new Igh haplotype in SWR/J mice, Igh ^p.Abbreviations used in this paper Igh immunoglobulin heavy chain - SDS sodium dodecyl sulfate     

Thorotrast uptake and transit in embryonic glia, heart fibroblasts and neurons in vitro

Thorotrast (colloidal ThO₂) is incorporated into coated vesicles, various agranular vesicles and sacs, and a surface-associated system of membranous channels in times as short as 1 min by single cultured glial and heart cells. Thorotrast appears in ‘C’-shaped bodies and in small, dense bodies of the lysosomal series within ca. 25 min. With longer chase periods, thorotrast ‘clears’ from all cytoplasmic organelles except the lysosomal series. The technique of applying thorotrast and using varying chase periods fails to distinguish a class of membranous organelles, located close to the cell periphery, that might serve as a source of new cell surface during locomotory activity. Similarly, thorotrast (colloidal ThO₂) is incorporated into almost all classes of membrane-bounded organelles of growth cones and axons of single nerve cells in vitro in times as short as 1 min. This includes elements of the smooth endoplasmic reticulum. No thorotrast enters the lysosomal granules in this short time. During various chase periods, the tracer disappears from the initial sites of incorporation and accumulates in dense bodies of the lysosome series within growth cones and axons. ‘C’-shaped bodies may be an intermediate in that process. No unique sites of endocytotic activity or of a complete absence of endocytosis were observed that could be correlated with growth cone function and axonal elongation, though the presence of the tracer in agranular sacs of the smooth endoplasmic reticulum in growth cones could reflect hypothesized cycling of cell surface (Bray, 1973).     

Observations on freeze-fractured membranes of a Trypanosome

Pure preparations of Trypanosoma brucei, free from plasma and cellular components were isolated from rat blood, and concentrated into loose pellets by low-speed centrifugation. Pellets were either processed for thin sectioning as a control for general morphology, or glycerol-treated after glutaraldehyde fixation for preparation of freeze-fracture replicas. Concentration of cells of 50,000–100,000/mm² of sectioned or fractured surface facilitated identification of fracture faces of the cell body, invaginated flagellar pocket and flagellum. Particle distribution and A and B faces of these regions of the cell are described. A collar of B face particles occurs around the neck of the flagellar pocket, possibly associated with a junction controlling ingress of ingested materials to coated vesicles formed along the membrane defining the pocket. A and B faces of the flagellum and adjoining surface of the cell body have shown that the only intra-membrane specialization corresponding to the miniature ‘maculae adherentes’ described previously in thin sections is probably an uninterrupted series of small clusters (3–6) of 80 Å particles on the A face of the flagellar membrane. It is proposed that these arrays represent attachment points for strands linking the axoneme and paraxial rod to the flagellar surface, and are not directly concerned with the physical adhesion of the flagellum to the cell body surface—a linkage that appears to be established within the extracellular gap between these apposed surfaces of the cell. The potential use of freeze-etching in further study of the external antigens of the infective cell is discussed.     

Observations on the mechanism of indirect induction by mating with ultraviolet-irradiated col I donors

Summary Irradiation of the colI donor itself is required to initiate indirect induction of phage following mating with a lysogenic recipient. Attempts to demonstrate that some other cytoplasmic inducer is responsible for induction have been negative. However the level of transfer of a viable (colicin-producing) colI factor (to a non-lysogenic recipient) is not correlated with the transfer of indirect induction (to a lysogenic recipient) either with respect to relative UV sensivities, or relative kinetics. Transfer of viable colI factor from the irradiated donor is delayed for up to 40 minutes whereas indirect induction is initiated early after contact. There is some lethality and inhibition of division of recipient cells mated with the irradiated donor, these effects similarly being initiated extremely early after cell contact. The question as to whether these effects of mating with an irradiated donor on the recipient follow transfer of inviable colI, or reflect a disturbance of transfer itself remains unresolved.     

DEVELOPMENT AND GERMINATION OF THE AZOTOBACTER CYST

The fine structure of Azotobacter vinelandii has been studied by means of electron microscopy of ultrathin sections made of the encysting and germinating cells. The organisms were fixed with KMnO₄ and embedded in epoxy resin. On an encystment medium the rod-shaped bacteria begin to assume an almost spherical form and then bark-like exine appears in 1½ to 2 days. The exine thickens and an electron permeable intine forms between it and the shrinking cell body. In 5 days the intine makes up more than half of the cyst volume and begins to show a definite two-layered structure. Meanwhile the peripheral bodies, which may be extensions of the cell membrane of the vegetative cell, disappear as the encystment progresses. The cell wall and membrane of the vegetative cell remain demonstrable as the confining structure of the shrinking central body of the mature cyst. In this central body lipoidal globules appear together with aggregations of nuclear material. Cyst germination begins with an increase in the size of the central body at the expense of the intine. The nuclear aggregations become more diffuse and the lipoidal globules disappear. The exine may be pushed outward and the bark-like fragments separate as the emerging vegetative cell develops. Invagination of the cell wall and membrane may occur at this stage leading to cell division. Empty exines remain as horseshoe-shaped structures.     

A PLUCHEA HYBRID FROM THE PACIFIC

Two species of Pluchea have been introduced into the Hawaiian Islands in the present century. These are P. indica, native to southeastern Asia, and P. odorata, native to the western hemisphere. Both are erect shrubs. Within the past 30 years a third Pluchea taxon, a sprawling shrub morphologically distinct from the two species, has appeared in the Hawaiian Islands and on other islands in the tropical Pacific. On the basis of morphology, fertility, meiotic behavior, and other evidence, it is concluded that the third taxon is a hybrid between the two species. The hybrid is highly sterile; it has a limited capacity for asexual reproduction. Metaphase I configurations for both species were found to be 10_II; the most frequent configuration in the hybrid was 8_II + 4_I. The hybrid is given a binomial.     

Pathogenesis of hemosiderosis in lemurs: Role of dietary iron,tannin, and ascorbic acid

Clinical disease associated with excess iron deposition (hemosiderosis) in the duodenum, liver, and spleen occurs in captive lemurs. In this report we review the occurrence of hemosiderosis and related disease in the Zoological Society of San Diego lemur collection; we then define and describe potential pathogenic factors with the goal of establishing rational husbandry methods to limit or prevent the disease. At the San Diego Zoo, all 49 lemurs necropsied since 1968 were hemosiderotic, the severity increasing with increasing age; liver and kidney disease were common. Our review of iron metabolism, current knowledge on the pathogenesis of hemosiderosis in humans, and the diets of captive and wild lemurs reveals several key dietary substances that may contribute to lemur hemosiderosis: iron, tannins, and ascorbic acid. In captivity, excess dietary iron (commercial monkey chow) and high levels of ascorbic acid (citrus fruits) lead to enhanced iron uptake and increased toxicity of stored iron due to free radical formation. In the wild, lemurs have an unusual preference for leaves, fruits, and bark high in tannin, a polyphenolic secondary plant compound that rapidly chelates iron, protein, and minerals in the gastrointestinal (GI) tract, preventing their absorption. These findings suggest that hemosiderosis in captive lemurs results from a diet high in iron, high in ascorbic acid, and lacking in tannin. Immediate correction of captive diets may limit hemosiderosis in lemurs in the future.