Broad-range effects of ionophore X-537A on pollen tubes of Lilium longiflorum

The effects of the broad-range cationophore X-537A on pollen tubes of Lilium longiflorum were investigated, using both light and electron microscopy. Pollen tube growth is completely inhibited within 30 min after the application of 5·10^-5 M ionophore X-537A; cytoplasmic streaming is stopped only after 60 min of ionophore treatment. Ultrastructurally, X-537A effects are a vacuolation of Golgi cisternae and a general vacuolation. The wall is thickened at the very tip. Coated vesicles and coated regions are enriched close to and at the plasma membrane. The results indicate that pollen tube tip growth needs a specific ion distribution.Abbreviations CTC chlorotetracycline - DMSO dimethylsulfoxide     

Multiple physical differences in the genome structure of functionally related bacteriophages P1 and P7

Summary Comparative restriction cleavage analysis of the genomes of bacteriophage P7, of several recombinant phages between P7 and P1, and of bacteriophage P1 allowed to draw PstI, BglII, BamHI and HindIII cleavage maps of all genomes studied. The data obtained complement Yun and Vapnek's (1977) conclusions with regard to areas of major nonhomology based on electron microscopical heteroduplex analysis and they identify several additional minor differences between P1 and P7. The use of hybrid phage strains allowed to locate the genes for particular functions on the physical genome map.Abbreviations Cm chloramphenicol - Ap ampicillin - bp base pairs - kb kilo-base pairs     

A search for the indianapolis-variant of human alcohol dehydrogenase in liver autopsy samples from North Germany and Japan

Summary Human liver alcohol dehydrogenase (ADH) variants were screened in random autopsy specimens from 53 North German and 34 Japanese individuals. Based on pH-activity profile and electrophoretic pattern, only ADH₂ and ADH₃ variants were detected. In relatively fresh specimens, an anodic band or -ADH band was also observed. The recently reported new molecular forms collectively called ADH_Indianapolis (Bosron et al. 1980) could not be demonstrated and therefore may be confined hitherto only to the American black population.This paper is dedicated to Professor Dr. Dr. H. Baitsch on his 60th birthday     

The uptake of copper by cell suspension cultures of Phaseolus vulgaris L. cv. SAXA

In experiments with cell suspension cultures of Phaseolus vulgaris L. cv. SAXA it could be demonstrated that gas-shocks caused by aeration decrease the uptake of copper. An aeration period of 30 h prior to the addition of copper was found to be sufficient to reestablish the copper uptake system. EDTA/sucrose solutions seemed to be adequate to remove the adsorbed copper. The time course of the uptake of copper showed saturation behaviour, whereas the velocity of the uptake was dependent on the given concentration of copper.     

Biliprotein assembly in the hemidiscoidal phycobilisomes of the thermophilic cyanobacterium Mastigocladus laminosus Cohn. Characterization of dissociation products with special reference to the peripheral phycoerythrocyanin-phycocyanin complexes

The dissociation products of isolated phycobilisomes of Mastigocladus laminosus were separated and analyzed by ultracentrifugation and, in part, by isoelectric focusing. With the exception of the allophycocyanin core, the sedimentation constants of peripheral phycocyanin- and phycoerythrocyanin-phycocyanin complexes lay in the range of 6 to 17S. The latter was represented by a 17S aggregate of two hexameric phycocyanins (dodecamer, dipartite unit). A complex with an absorption maximum at 610 nm (phycocyanin) and a shoulder at 580 nm (phycoerythrocyanin), a fluorescence emission maximum at 645 nm and a sedimentation constant of 11 S is described as a heterogeneously composed hexamer of ()₃-phycoerythrocyanin-()₃-phycocyanin. It was stable under extended dissociation in the cold and under isoelectric focusing. An aggregate of 14 S with an absorption maximum at 576 nm and a shoulder in the fluorescence emission spectrum at 625 nm (phycoerythrocyanin) in addition to the maximum at 645 nm (phycocyanin) is interpreted as a polar phycoerythrocyanin/ phycoerythrocyanin-phycocyanin complex. Combining these complexes with phycocyanin dodecamers creates peripheral rods of the phycobilisome. A proposal of the phycobiliprotein distribution within the phycobilisome of M. laminosus is presented.Abbreviations APC allophycocyanin - PC phycocyanin - PE phycoerythrin - PEC phycoerythrocyanin     

Studies on immobilized α-glucosidase from brewers yeastSaccharomyces carlsbergensis

Summary -Glucosidase isolated from brewer's yeast (Saccharomyces carlsbergensis) was immobilized using hydroxymethacrylate activated by cyanogen bromide as a carrier. Up to a hundred-fold increase in the stability of the enzyme was observed after immobilization. The yield in activity (bound/applied) was up to 30%. Before developing the process of enzymatic cleavage of maltose further we evaluated the kinetic properties of the enzyme catalyst, as we had observed earlier that the soluble enzyme is strongly inhibited by the product glucose. This is even more pronounced with the immobilized -glucosidase leading in this case to a linear relation between initial rate and substrate concentration, so K_M (approx.) values can no longer be defined due to the dominating influence of the product inhibition.     

Possible sites of ultrafiltration in Tubifex tubifex Müller (Annelida,Oligochaeta)

Summary The endothelia of Tubifex tubifex Müller consist of myoendothelial cells, chloragocytes, or podocytes. The latter seem to occur only as windows on the ventral vessel which has an endothelium of myoendothelial cells elsewhere. The podocytes are large cells, with several processes on the inner side which ramify into several pedicels. These are aligned upon the outside of the basement membrane which lines the inside of the endothelium. The gaps between adjacent pedicels are about 40 nm wide. In capillaries fenestrated endothelia occur with irregular spacings measuring up to 0.4–1 m. A diaphragm in podocytes or capillary fenestrations do not seem to exist. The basement membrane is the only continuous layer lining the blood vessels and capillaries of Tubifex with a rather uniform diameter in the range of 50 nm. It is the only permeability barrier between blood and coelomic fluid.     

Multiple forms of phycoerythrin-545 from Cryptomonas maculata

Three multiple phycoerythrin-545 forms were purified from crude extracts of Cryptomonas maculata by preparative isoelectric focusing. The phycoerythrin forms are charge isomers with isoelectric points at 7.83, 5.05 and 4.84. The multiple pigment forms have similar molecular weights of 44500 daltons and are composed of subunits of unequal size in a 1:1 stoichiometry with molecular weights of () 9900 and () 15700 daltons, twice. The proposed quarternary structure of the native pigments is ()₂()₂.The charge differences of the phycoerthrins are caused by a charge heterogeneity of the light subunits, as revealed by urea gel electrophoresis. The chains of pigment form pI 7.83 had a greater electrophoretic mobility than those subunits of the acidic pigment forms pI 5.05 and pI 4.84.The phycoerythrin forms have an absorption spectrum with similar absorption maxima at 544 nm, but differ in the position of the long wavelength shoulders lying at 555 and 557 nm in the negatively charged pigment forms and at 560 nm for the phycoerythrin form with a pI at 7.83.The fluorescence emission spectra coincide in their asymmetrical shape with shoulders at about 620 nm; they slightly differ int he position of the emission maxima at 586 nm for the phycoerythrins with pIs at 4.84 and 5.05 and at 584 nm for phycoerythrin with pI at 7.83.Abbreviations PC phycocyanin - PE phycoerythrin - pI isoelectric point - SDS sodium dodecyl sulphate     

Metabolic interlock between the acetolactate synthase isoenzymes and lysine biosynthesis in Escherichia coli K-12

Summary Some of the strains containing mutations in the genes for the acetolactate synthase isoenzymes are temperature sensitive (ts). Suppression of the acetolactate synthase defect due to one of these mutations suppresses also the ts phenotype; moreover, a genetic cross shows that the two phenotypes cannot be dissociated.The ts phenotype is accompanied by a decreased efficiency of transduction with Pl phage. Observations at the light microscope show formation of abnormal cells. Under specific conditions diaminopimelate stimulates growth and restores normal transduction efficiency. The rate of diaminopimelate formed and excreted by non-growing cells decreases when an acetolactate synthase mutation is present.We give evidence that the ts phenotype is due to an increased formation of lysine from diaminopimelate; this causes a starvation for the latter and therefore cell wall abnormalities. In fact, even at the permissive temperature, the lysine pool is 8x increased in a strain with an acetolactate synthase defect, while a slight decrease in the diaminopimelate pool is observed. Moreover, introduction into a ts strain of a mutation in lysA (the gene coding for diaminopimelate decarboxylase) cures the ts phenotype. Finally among the temperature resistant revertants we found some lysine auxotrophs.