Ueber Astragalus monspessulanus L., A. Wulfeni Koch,A. incanus L. und A. incurvus Desf

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Rassenumwandlung bei Aspergillus niger

Zusammenfassung Es wurde versucht, zwei physiologisch durch die Oxalsäurebildung und die dadurch beeinflußte Richtung der Autolyse verschiedene Rassen von Aspergillus niger ineinander überzuführen. Dies gelang durch Einwirkung von Trocknen bzw. Erhitzen der Sporen und durch Passage über Tannin- und Oxalsäurelösung.Der Übergang der Rasse Göttingen neu (viel Oxalsäure, saure, helle Autolyse) in die Rasse Göttingen alt (wenig Oxalsäure, neutrale bzw. alkalische, dunkle Autolyse) ging bedeutend leichter als umgekehrt.Durch Oxalsäurepassage wird die Rasse Göttingen alt stärker in der Richtung der sauren, die Rasse Göttingen neu stärker in der Richtung der neutralen Autolyse beeinflußt.Die jeweiligen Veränderungen erwiesen sich drei bis acht Generationen, soweit untersucht, konstant.Mit Hilfe ähnlicher Methoden dürften die Veränderungen bei diesem Pilz der experimentellen Analyse zugänglich werden.Kurzer Auszug aus der Dissertation von Paul Hugo Kreutzmann, Untersuchungen über die Variabilität von Aspergillus niger. Göttingen 1935.     

Anfrage wegen der Bastartfrucht desLycopersicum esculentum undCapsicum annuum

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An nptI-sacB-sacR cartridge for constructing directed, unmarked mutations in gram-negative bacteria by marker exchange-eviction mutagenesis

A technique for marker exchange-eviction mutagenesis that enables the construction of directed, unmarked mutations in Gram-negative bacteria was demonstrated in Erwinia chrysanthemi. The technique employs an nptI-sacB-sacR cartridge that is carried on a 3.8-kb BamHI fragment and confers kanamycin (Km) resistance and sucrose sensitivity (due to the production of levansucrase by sacB) in E. chrysanthemi. The cartridge was inserted into a Sau3A site in a cloned E. chrysanthemi pelC gene (encoding pectate lyase isozyme PLc) and then introduced into the Erwinia genome by gene exchange recombination. The resulting mutant was KmR, sucrose-sensitive, and PLc-deficient. The cartridge was then excised from the plasmid-borne pelC gene by PstI cleavage to leave a 28-bp frame-shifting insertion. The pelC allele containing the 28-bp insertion was exchanged for the chromosomal allele containing the nptI-sacB-sacR cartridge by selection for sucrose tolerance. The resulting E. chrysanthemi mutant was Kms and PLc-deficient. The technique permits the construction of complex strains with many directed mutations without the introduction of a corresponding number of antibiotic resistance markers and should prove useful, for example, in exploring the role of the multiple pel genes in E. chrysanthemi.     

Direct carrier detection by in situ suppression hybridization with cosmid clones of the Duchenne/Becker muscular dystrophy locus

Summary A basic problem in genetic counseling of families with Duchenne/Becker muscular dystrophy (DMD/BMD) concerns the carrier status of female relatives of an affected male. In about 60% of these patients, deletions of one or more exons of the dystrophin gene can be identified. These deletions preferentially include exon 45, which can be detected by multiplex polymerase chain reaction (PCR) and Southern blot analysis of genomic cosmid clones that map to this critical region. As a new approach for definitive carrier detection, we have performed chromosomal in situ suppression (CISS) hybridization with these cosmid clones in female relatives of four unrelated patients. In normal females, most metaphases showed signals on both×chromosomes, whereas only one×chromosome was labeled in carriers. Our results demonstrate that CISS hybridization can define the carrier status in female relatives of DMD patients exhibiting a deletion in the dystrophin gene.     

Isolation and sequencing of a cDNA clone encoding lysosomal membrane glycoprotein mouse LAMP-1. Sequence similarity to proteins bearing onco-differentiation antigens

We have isolated and sequenced a cDNA clone encoding the mouse LAMP-1 (mLAMP-1) major lysosomal membrane glycoprotein. The deduced protein sequence, which included the NH2-terminal portion of the mLAMP-1 molecule, consisted of 382 amino acids (Mr 41,509). The predicted structure of this protein included an NH2-terminal intralumenal domain consisting of two homology units of approximately 160 residues each separated by a proline-rich hinge region. Each homology unit contained four cysteine residues with two intercysteine intervals of 36-38 residues and one of 68 or 76 residues. The molecule also contained 20 asparagine-linked glycosylation sites within residues 1-287, a membrane-spanning region from residues 347 to 370, and a carboxyl-terminal cytoplasmic domain of 12 residues. The biochemical properties and amino acid sequence of mLAMP-1 were highly similar to those of two other molecules that have been studied as cell surface onco-differentiation antigens: a highly sialylated polylactosaminoglycan-containing glycoprotein isolated from human chronic myelogenous leukemia cells (Viitala, J., Carlsson, S. R., Siebert, P. D., and Fukuda, M. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, in press) and the mouse gp130 (P2B) glycoprotein, in which an increase in beta 1-6 branching of asparagine-linked oligosaccharides has been correlated with metastatic potential in certain tumor cells (Dennis, J.W., Laferte, S., Waghorne, C., Breitman, M.L., and Kerbel, R.S. (1987) Science 236, 582-585).     

Pre-lysosomal divergence of alpha 2-macroglobulin and transferrin: a kinetic study using a monoclonal antibody against a lysosomal membrane glycoprotein (LAMP-1)

We have used electron microscopic immunocytochemistry to compare the distribution of LAMP-1, a marker for lysosomal membranes, with the intracellular localization of alpha 2-macroglobulin (alpha 2-M) and transferrin at various time points after their endocytosis into cultured NIH 3T3 cells. The purposes of this study were (a) to determine how soon endocytic ligands reach lysosomal organelles, (b) to examine whether the intermediate endocytic vesicles gained lysosomal markers gradually or in a precipitous, discrete event, and (c) to examine the relationship, if any, between the pathway of recycling ligands and lysosomes. At early time points (0-5 min) after initiation of endocytosis, most structures containing alpha 2-M labeled with colloidal gold (receptosomes) were not labeled by anti-LAMP-1 detected using ferritin bridge or peroxidase immunocytochemistry. At late time points (greater than or equal to 15 min), the structures containing alpha 2-M (lysosomes) were strongly labeled by anti-LAMP-1. In contrast, transferrin that was directly labeled with ferritin was mostly located in LAMP-1-negative structures at all time points studied. The proportion of alpha 2-M-gold containing vesicles strongly labeled for LAMP-1 roughly paralleled the proportion of alpha 2-M-gold-containing structures positive for cytochemically detectable acid phosphatase. Our data indicate that ligands such as transferrin that are internalized through coated pits and receptosomes, but not delivered to lysosomes, do not traverse a lysosomal organelle compartment as marked by LAMP-1 content. Ligands such as alpha 2-M that are destined for lysosomal delivery reach a LAMP-1-positive organelle compartment only after they traverse LAMP-1-negative, non-lysosomal vesicles previously described as receptosomes.     

Mutations in Methanobacterium formicicum conferring resistance to anti-80S ribosome-targeted antibiotics

Summary Mutants of Methanobacterium formicicum resistant to the anti-80S ribosome-targeted inhibitor anisomycin were isolated and characterized. The resistance phenotype is correlated with a mutationally altered 50S ribosomal subunit. Anisomycin resistance in the mutants is accompanied by cross-resistance to other inhibitors of the 80S peptidyl-transferase centre like narciclasine, bruceantin, trichodermin and verrucarin A and by hypersensitivity to sparsomycin. This phenotype is identical to that reported for anisomycin-resistant mutants of yeast; it appears therefore, that the anisomycin interaction sites on the 70S ribosomes from M. formicicum bear the structural features typical of eukaryotic 80S organelles.