Subcellular localization of gamma-glutamyltransferase in calf thymocytes.

The subcellular localization of gamma-glutamyltransferase in calf thymocytes was investigated and compared with that of alkaline phosphodiesterase I, alkaline nitrophenyl phosphatase, succinate-tetrazolium oxidoreductase (succinate-INT reductase) and lactate dehydrogenase after two different methods of cell disruption and differential centrifugation. Most of the activity was recovered in the crude membrane fractions (43.0%), but significant amounts co-pelleted with the large-granule (mitochondria) fractions (31%). The specific activity of the gamma-glutamyltransferase in the purified plasma membrane was 30-50 times that of the enzyme in the cell homogenate and had a similar subcellular distribution to the plasma-membrane markers, alkaline phosphodiesterase I and alkaline nitrophenyl phosphatase. It was concluded that gamma-glutamyltransferase was primary a plasma-membrane-bound enzyme, and that its location in other subcellular fractions was probably due to their contamination with plasma-membrane vesicles.     

The morphology of the cement gland apparatus of Larval Pterophyllum scalare Cuv. & Val. (Cichlidae,Teleostei)

Summary The cement gland apparatus of newly hatched Pterophyllum scalare Cuv. & Val. was examined by histology, scanning and transmission electron microscopy. The whole organ is composed of three pairs of endoepithelial, ductless glands, which cause prominent elevations on the larval head and are found in a specific arrangement. Each single gland is represented by an aggregation of elongated, tubular secretory cells surrounding a pyriform acinus. It overlies a basal lamina and is covered by the outer layer of the bilaminar embryonic epidermis.Two different types of secretory cells can be distinguished. One type is restricted to the bottom of the cavity. It is characterized by multiform cytoplasmic protrusions, which project into the gland's cavity. The secretory granules contain a network of light filamentous material. The second type constitutes the side wall of the acinus. It does not develop any protrusions. The contents of the secretory granules is of very high and homogeneous electron density. The mechanism of extrusion is discussed for both cell types. All secretory cells show a strong PAS-reaction. In SEM a circular microridge pattern with attached mucus globules can be recognized on the larval epithelial surface.Dedicated to Prof. Dr. H. Leonhardt on the occasion of his 60th birthday     

Dictyocaulus viviparus: Migration in agar of larvae subjected to a variety of physicochemical exposures

Dictyocaulus viviparus larvae were exposed to ox bile and CO₂ at intervals during their cultivation to the infective stage. Preinfective and young infective larvae were stimulated by CO₂. Bile slightly inhibited preinfective larvae, but stimulated the infective stage. Old coiled, resting infective larvae were stimulated by bile down to a concentration of 10 ppm of bile dry matter, by vertebrate biles of pig, sheep, newborn calf, cow, guinea pig, dog, and chicken, as well as by defatted bile dry matter and by glyco-, tauro-, glycodeoxy-, and taurodeoxycholates. Continuous bile exposure appeared necessary to maintain high larval activity. A high pCO₂ as well as a low redox potential potentiated the effect of bile, but had no effect alone. Exposure to pepsin-HCl and to trypsin had only a minor stimulatory effect.     

Bromine oxidation of 1,2-O-isopropylidene-α-d-Glucofuranose and sucrose

Sucrose and $\text{1,2-O-}\text{isopropylidene-α-}\text{d}\text{-glucofuranose}$ (1) were oxidised with bromine in aqueous solution at pH 7 and room temperature. The resulting keto derivatives were converted into their more-stable O-methyloximes, which were characterised by spectroscopic and chromatographic methods. Oxidation of 1 occurred at C-3 and C-5, with a preference for C-5. In the sucrose derivatives isolated after oxidation, those having a keto group in the glucopyranosyl moiety preponderated. The axial fructofuranosyl aglycon protects position 3 in the glucopyranosyl group and oxidation occurs only at C-2 and C-4. Small amounts of sucrose oxidised at C-3 in the fructofuranosyl moiety were also found.     

Actions of an antispermatogenic, but non-mutagenic, indenopyridine derivative in mice and Salmonella typhimurium.

This paper describes a new antispermatogenic agent. Following single oral administration to mice, the indenopyridine derivative (4aRS,5SR,9bRS)-2-ethyl-1,3,4,4a,5,9b-hexahydro-7-methyl-5-p-tolyl-2H-indeno(1,2-c)pyridine hydrochloride, code No. 20-438, produced long-lasting inhibition of the spermatogenic process at dose levels of 10 mg/kg (1/40 of the lowest lethal dose) and higher. Testes weights were significantly reduced from days 2--217 after treatment, and no clear-cut evidence of a recovery was found during this time. The fertility of treated males was normal during the initial 2 weeks after treatment, followed by partial or total sterility in weeks 3--6, and incomplete recovery in weeks 7--29 after treatment. The antifertility effects were caused by maturation depletion of the germ cells, leading to oligospermia. The following rank of decreasing "susceptibility" of the germ cells was observed: Spermatocytes greater than early spermatids, intermediate spermatogonia greater than stem cells. Sperm and late spermatids were not affected. Despite the characteristic specific germ-cell pattern of antifertility effects, 20-438 showed neither indications of pre- and post-implantational dominant lethality, nor mutagenic potentiality as measured by cytogenetic analysis of spermatocytes or spermatogonia, the sperm abnormality assay, the micronucleus test, and the Salmonella assay. These data suggest that the action of 20-438, leading to oligospermia, does not involve genetic toxic effects.     

Oxygen affinities of maternal and fetal hemoglobins of the viviparous seaperch,Embiotoca lateralis

Summary The striped seaperch,Embiotoca lateralis, is a viviparous teleost. The hemoglobins of adult and fetal seaperch are both tetrameric proteins which in their native state appear to be indistinguishable from one another by electrophoresis. However, differences in the subunit structure of maternal versus fetal seaperch hemoglobins can be detected by electrophoresis in urea with a reducing agent, amino acid analyses and peptide maps of the respective proteins. Furthermore, stripped adult and fetal hemoglobins have different oxygen binding affinities at all pH's tested between pH 6.8 and 8.0. Mid-gestation fetal hemoglobin has a higher oxygen affinity than late-gestation fetal hemoglobin which in turn has a higher affinity than that of the adult hemoglobin. All three stripped hemoglobins show a similar Bohr effect (=–0.9). These data suggest that a difference in oxygen affinities exists in vivo between the adult and fetal blood of the seaperchEmbiotoca lateralis and that it can be explained in part by the presence of a structurally unique fetal hemoglobin. This report is the first to provide evidence for a mechanism of maternal-fetal oxygen transfer in a teleost fish.Abbreviations A adult - LF late-gestation fetal - MF mid-gestation fetal (hemoglobins)     

Vascular reactions to horseradish peroxidase in the guinea pig

Summary Albino guinea pigs were given intradermal injections of the protein tracer horseradish peroxidase. In a 0.1 mM concentration the tracer did not increase vascular permeability to Evans blue-labelled plasma proteins. In a 1 mM concentration, however, the peroxidase induced a local vascular leakage. This leakage was almost totally inhibited by pretreating the animals with acetylsalicylic acid, while antihistamine had only a weak inhibitory effect. We therefore believe that prostaglandins are important mediators in this HRP-induced vascular reaction.     

Dipeptidyl peptidase IV inhibits the polymerization of fibrin monomers

A highly purified dipeptidyl peptidase IV from human placenta cleaves glycylproline from the N-terminal end of the fibrin α chain and inhibits the clotting of fibrin monomers. This result underlines the importance of the amino terminus of the fibrin α chain as an aggregation site masked by fibrinopeptide A. We speculate that the peptidase may hinder blood coagulation in intact vessels in vivo, because it is located on the surface of the capillary endothelium.     

Sarcocystis neurona n. sp. (Protozoa: Apicomplexa), the etiologic agent of equine protozoal myeloencephalitis

Sarcocystis neuronan n. sp. is proposed for the apicomplexan taxon associated with myeloencephalitis in horses. Only asexual stages of this parasite presently are known, and they are found within neuronal cells and leukocytes of the brain and spinal cord. The parasite is located in the host cell cytoplasm, does not have a parasitophorous vacuole, and divides by endopolygeny. Schizonts are 5-35 microns x 5-20 microns and contain 4-40 merozoites arranged in a rosette around a prominent residual body. Merozoites are approximately 4 x 1 micron, have a central nucleus, and lack rhoptries. Schizonts and merozoites react with Sarcocystis cruzi antiserum but not with Caryospora bigenetica. Toxoplasma gondii, Hammondia hammondi, or Neospora caninum antisera in an immunohistochemical test.