Analysis of active nucleolus organizing regions in Capsicum (Solanaceae) by silver staining

Nucleolar activity of 22 samples belonging to nine diploid species of Capsicum was analyzed in somatic metaphases and interphase nuclei. They are: C, chacoënse, C. parvifolium, C. frutescens, C. chinense, C. annuum var. annuum, C. baccatum var. pendulum, C. pubescens, all with 2n = 24, and C. mirabile var. mirabile and C. campylopodium with 2n = 26. Silver staining was applied for the first time in Capsicum, providing useful markers for chromosome identification in combination with other banding techniques already employed in the genus. From two to eight AgNORs (silver-stained nucleolus organizing regions) were found in the diploid complement of the taxa studied. Nucleolar organizers are located at secondary constrictions of chromosomes which are conventionally stained or banded (C-banding or fluorochrome banding). Polymorphism of AgNORs and attached satellites often occurs. Nucleoli are usually fused to a variable extent. Number and position of active rDNA loci are variable not only between but also within species and populations. Homologies in position of NORs between species were established. The data obtained are related to previous conclusions on phylogenetic relationships in Capsicum. Possible trends of karyotype evolution concerning nucleolar organizers are discussed, and four NORs in the diploid complement (on chromosome pairs #1 [m] and #12 [st]) are regarded as the plesiomorphic condition.     

Measurement and prediction of the rates of spontaneous transfer of phospholipids between plasma lipoproteins

The purpose of this report is to develop a correlation between the hydrophobicity of a phospholipid as measured by reversed-phase high-performance liquid chromatography and its rate of spontaneous transfer and to use this correlation to predict the rate of transfer of any homologous lipid from any lipoprotein. We have studied the mechanism of transfer of a series of fluorescent or radiolabeled phospholipids among natural and reassembled serum lipoproteins. Fluorescent phosphatidylcholines included those with 9-(1-pyrenyl)nonanoic acid in the sn-2 position and lauric, myristic, palmitic, stearic, oleic or linoleic acid at sn-1. The radioactive phosphatidylcholines contained [3H]oleic acid in the sn-2 position and lauric, myristic, or palmitic acid at sn-1. The kinetics of transfer of the pyrene-labeled lipid were followed by changes in the excimer fluorescence, and that of the radioactive lipids by separation of the donor (lipid-apolipoprotein recombinant) from the acceptor (single bilayer vesicles) on a column of Sephacryl S-200. The retention time of each lipid was measured by high-performance hydrophobic chromatography through a Waters radially compressed C18 column eluted with 75% isopropanol and 25% triethylammonium phosphate (0.15 M). A linear relationship was observed between the rate-constant of transfer and the retention time which suggest that the rate of desorption of phosphatidylcholines from lipoproteins and vesicles is controlled predominately by the hydrophobic effect. For a homologous series of lipids, the rate of transfer can be predicted from retention times obtained from hydrophobic chromatography. The kinetics of transfer of 1-lauroyl-2-[9-(1-pyrenyl)nonanoyl] phosphatidylcholine between isolated human serum lipoproteins exhibits a linear correlation between the transfer half-time and the size of the donor lipoproteins. As a consequence, transfer from very-low-density lipoprotein is 10-times slower than that observed from high-density lipoproteins. The observed correlations between phospholipid transfer rates and both the Stokes radius of the donor and the retention time of the phospholipid on a hydrophobic column permit one to calculate the rate of transfer of homologous molecules between lipid-protein complexes. The results predict that the spontaneous transfer of phospholipids between plasma lipoproteins would be too slow to be a physiologically important phenomena.     

Physical map of the bacteriophage L (Salmonella typhimurium)

Abstract A circular restriction map of the genome of the phage L ( Salmonella typhimurium ) has been constructed with five restriction endonucleases, Eca I, Eco RI, Bam HI, Bgl I, and Pst I. The Eco RI fragments of phage-L DNA were cloned into pACYC184, and the resulting recombinant plasmids pL1, pL2,…,pL7 were introduced into Salmonella typhimurium . The genes present on the fragments cloned were identified by the marker rescue experiments with the L-phage amber mutants. A physical gene map of the L genome obtained in this way was compared with that of P22.     

Topo-optische Färbung der Erythrocytenmembran mit Thiazin- und Chinolinfarbstoffen

Zusammenfassung Die Untersuchungen erwiesen, daß die Farbstoffe 1:9-Dimethyl-Methylenblau, Azur A und N,N-Diäthylpseudoisozyaninchlorid für topo-optische Reaktionen an der Membran von Erythrocyten geeignet sind. Die Farbstoffmoleküle werden an der Membran orientiert gebunden. Ihre Bindung kann durch Behandlung mit Präzipitationslösungen stabilisiert werden, und zugleich wird die Anisotropie verstärkt. Die optische Analyse ergab, daß 1:9-Dimethyl-Methylenblau und Azur A radiär zur Membran ausgerichtet sind, während sich N,N-Diäthylpseudoisozyaninchlorid membranparallel anlagert.

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Tope-optical staining with thiazin and quinolin dyestuffs of the erythrocyte membrane

Summary The present studies prove the dyestuffs 1.9-dimethyl methyleneblue, azure A and N,N-diethylpseudoisocyanine chloride suitable for topo-optical reactions with the membrane of the red blood cell. The dye molecules are bound in orientated fashion. Treatment with precipitants stabilizes the binding of dye molecules and, in addition, it enhances the birefringence. Optical analysis revealed 1.9-dimethyl methyleneblue and azure A bound in radial position, however, N,N-diethylpseudoisocyanine chloride was bound parallel to the membrane's plane.

     

Arthopyrenia endobrya,spec. nov., eine hepaticole Flechte mit intrazellulärem Thallus aus Brasilien

Arthopyrenia endobrya from Southern Brazil is illustrated and described as a new species of lichens. The thallus is composed of filamentous green algae loosely surrounded by fungal hyphae. Both symbionts grow endophytically within the leaf cells of two species ofLejeuneaceae (Hepaticae). The algae and hyphae penetrate the cell walls of the host by means of fine perforations. The ascocarps develop between the leaves and perforate them with their apical region. The classification as a member of the genusArthopyrenia is preliminary.

     

Cell division and sister chromatid exchanges in 45,X/46,X,i(Xq) mosaicism

Summary The kinetics of cell division and sister chromatid exchanges were studied in PHA-stimulated short-term cultivations of peripheral blood by means of the BUDR/FPG technique in controls and in five patients with 45,X/46,X,i(Xq) mosaicism. No significant differences in the length of the cell cycle were observed between 45,X/46,X,i(Xq) and control 46,XX cells. The number of SCE on late i(Xq) was only nonsignificantly elevated (0.6 per i(Xq)) against the value expected on the basis of its relative length.