The lysis effect of bull spermatozoa on gelatin substrate film methodical investigations.

Proteolytic activity in the acrosomes of ejaculated bull spermatozoa was demonstrated using an autoradiographic film as a gelatin substrate. Incubation of the spermgelatin adducts at +37 degrees C and 94% humidity, which was kept constant by ventilating an incubator with water-saturated compressed air, yielded reproducible results. Gelatin depolymerisation started adjacent to the posterior segment of the acrosome within 30 to 60 s after application of individual spermatozoa to the substrate membrane and, finally, increased to a white circular digestion area enveloping the entire sperm head. The observed gelatinolysis seems to be mainly caused by acrosin, the trypsin-like acrosomal proteinase. This conclusion is supported by the positive correlation (r = +0.83, P is less than or equal to 0.01) found between the mean values of the lysis areas of individual spermatozoa on gelatin films and the acrosin activity of the sperm population measured with Bz-Arg-OEt as substrate after acidic extraction of the spermatozoa. In addition, prior saturation of the substrate layers with acrosin inhibitor (SSPI-I, II) from boar seminal plasma prevented the lysis reaction. Extraction of acrosin from the spermatozoa before application to the gelatin membranes resulted in a complete loss of any proteolytic activity. If spermatozoa were stored for 4 to 6 days at +4 degrees C or -20 degrees C in Tris buffer and afterwards applied to the substrate layer, lysis areas of individual spermatozoa differed markedly. Spermatozoa from undiluted ejaculated frozen at -20 degrees C showed no proteolytic effect on gelatin films. In general, there was a high correlation (r = +0.83, P is less than or equal 0.01) between the number of "living cells" characterized by live-dead staining and the percentage of spermatozoa active on the substrate membranes.     

Extrachromosomal inheritance of paromomycin resistance in Saccharomyces cerevisiae. Genetic and biochemical characterization of mutants

Summary In Saccharomyces cerevisiae, mutants were isolated which show high resistance to the aminoglycoside paromomycin. Amino acid incorporation of mitochondria isolated from such mutant strains proved also to be paromomycin resistant. All of them are cross-resistant to the structurally related antibiotic neomycin. Three independent methods revealed the resistance to be extrachromosomally, presumably mitochondrially inherited.     

Relation between the nuclei and the nucleoli during cell differentiation in roots of Vicia faba volumetric and cytochemical analysis

Summary The behaviour of the nuclei and the nucleoli of roots of Vicia faba during cell differentiation was studied quantitatively. The relations between these cell constituents and the polyploidy was analysed. The study was made on isolated nuclei and nucleoli and on plastic sections. A method for the isolation of nuclei and nucleoli of secondary roots fixed in formol was modified and another developed for material fixed in ethanol/acetic acid mixture. The volumetric investigation showed that the nuclear volume increases while the nucleolar decreases during cell differentiation. The mean number of nucleoli decreases. In Vicia faba there is no relation between the ploidy and the volume of nuclei and nucleoli; the protein synthesis rate has an influence on the size of these organelles. Quantitative investigation has shown the proportionality of dry weight, DNA, total protein, histone, protein-bound lysine and arginine content of the nuclei and their ploidy. The same experiments made on nucleoli showed linear relation between their content and volume. The concentration of analysed substances in constant in nucleoli.     

Beobachtungen einer Familie mit Galaktosämie und “Duarte-Variante”

Zusammenfassung Die Familienuntersuchungen einer galaktosämischen Patientin ergaben bei 5 Verwandten das gleichzeitige Vorkommen eines galaktosämischen Merkmals und eines varianten Enzyms (Duarte-Variante). Aktivität der Gal-1-Phosphat-Uridylyltransferase wurde mit Hilfe eines modifizierten UDPG-Verbrauchstests nach Beutler u. Baluda bestimmt.

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Summary 5 relatives of a patient with galactosemia showed a simultaneous occurence of the characteristic sign of galactosemia and of a variant enzyme (Duarte variant). The activity of Gal-1-Phosphat-Uridylyltransferase was determined by a modification of the UDPG-consumptiontest of Beutler and Baluda.

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With the aid of: Landesamt für Forschung des Landes Nordrhein-Westfalen und Landschaftsverband Westfalen Lippe.     

Biosynthesis of the carbohydrate portion of immunoglobulins. Incorporation of radioactive fucose into immunoglobulin G1 synthesized and secreted by mouse plasma-cell tumour MOPC 21

Incorporation of radioactive fucose into the immunoglobulin G1 myeloma protein secreted by mouse plasma-cell tumour MOPC 21 is stereospecific for the l-isomer. Heavy chains of the secreted form of the myeloma protein carry 90% of the label in fucose residues of their carbohydrate moieties. A small but significant amount of the intracellular immunoglobulin G1 of the mouse plasma-cell tumour MOPC 21 appears to be labelled. Serum in the incubation medium supplies low-molecular-weight diffusible substances necessary to maintain continuous secretion of fucose-labelled myeloma protein beyond 2-3h, and of leucine-labelled myeloma protein beyond 6-8h. In medium containing extensively dialysed serum the secretion of leucine- and fucose-labelled myeloma protein can be restored by the addition of 250mum-d-mannose, 250mum-d-galactose and 250mum-glucosamine. Synthesis and secretion appear to be facilitated in the presence of these sugars, although secretion of myeloma protein devoid of terminal fucose residues is possible for a limited time-period.     

Synthesis of phenazine and phenoxazinone derivatives of geldanamycin as potential polymerase inhibitors

Derivatives of geldanamycin—phenazines and phenoxazinones, some of them analogous to rifazine in the rifamycin series—have been synthesized. Most of the geldanamycin derivatives were highly effective inhibitors of RNA-dependent DNA polymerase from Rauscher leukemia virus. A simple analog containing the aromatic chromophore of the derivatives but without the ansa ring also showed viral inhibition.     

Die Photosynthese plasmolysierter Wasserpflanzen

• 1 . Mit Hilfe der elektrochemischen Sauerstoffbestimmung war es möglich, die Photosynthese dreier submerser Wasserpflanzen — Ceratophyllum demersum, Elodea canadensis und Riccia fluitans — in verschieden konzentrierten Zuckerlösungen kontinuierlich zu bestimmen. Überführt man die Pflanzen von Leitungswasser in 0,5 mol Mannitlösung (ebenfalls mit Leitungswasser angesetzt), plasmolysieren zwar die drei Arten sehr rasch, doch nur bei Riccia zeigte sich eine leichte Depression der Photosynthese
• 2 . Bei der Überführung in 1 mol Glucoselösung reagierten die drei Arten mit einer deutlichen Schockwirkung (Abb. 2), die jedoch bei Ceratophyllum vollständig überwunden wurde
• 3 . Eine schrittweise Überführung von Elodea in ansteigende Glucosemolaritä-ten zeigte zwischen 0,6 und 0,7 mol Glucose ein schrittweises Absinken der Photosynthese zu O. Eine Überführung in normales Leitungswasser zeigte bei jenen Sprossen, die plasmolysiert waren, keine Erholung. Bei an starkes Sonnenlicht angepaßten Elodea-Pflanzen war der kritische Bereich mit sofortigem Abfall der Photosynthese auf 1,8 bis 2 mol Glucose verschoben
• 4 . a) Es können also in hypertonischen Lösungen zwei Reaktionen unterschieden werden; eine Langzeitreaktion bei Konzentrationen der Grenzplasmolyse ohne sofortige Senkung der Photosynthese, jedoch gefolgt vom völligen Zusammenbruch des Lebenszustandes nach einigen Stunden b) Eine sofortige Hemmung der Photosynthese bei höheren Konzentrationen
• 5 . Die Atmung war weit weniger empfindlich gegenüber dem osmotischen Wasserverlust als die Photosynthese

     

Web spider's dilemma: a risky move or site dependent growth

Summary Nephila clavipes inhabiting adjacent habitats showed differences in rate and ratio of growth. Spiders inside the forest fed less, grew slower and stayed smaller than those at the forest edge, a richer environment. The mortality rate in this habitat was about 1% per day, the mortality of vagrant males was even higher. Experimentally fed spiders did not shift their webs readily, even starving individuals stayed much longer than expected. The spiders avoided frequent moves and in a poor site grew more slowly and in smaller size increments. It seems that the costs of small adult size are less than the risks of active foraging.     

The complete covalent structure of hirudin. Localization of the disulfide bonds

Hirudin, the thrombin-specific inhibitor from the leech Hirudo medicinalis, is a single-chain polypeptide (65 amino-acid residues) linked by three disulfide bridges. Localization of the three disulfide bonds could be assigned on the basis of the structures of cystine peptides derived by high performance liquid chromatography separations of thermolysinolytic digest of native hirudin. By characterization of the nine major fragments by amino-acid analysis, N-terminal amino-acid determination and sequence analysis, the following disulfide linkages were identified: Cys6-Cys14, Cys16-Cys28 and Cys22-Cys39. Due to the lack of any closer sequence homology and topological structural homology to other serine proteinase inhibitor proteins, hirudin seems to be unique in its primary structure and hence designates an unknown inhibitor family.