Respiration and Motility in Starfish Spermatozoa at Various Times in the Breeding Season

In the spermatozoa of Asterias amurensis , patterns of changes in the respiratory rate and motility following dilution of dry sperm in sea water varied among batches and were classified into three types. The type I spermatozoa were immotile and exhibited quite low respiratory rate. Ethylenediamine tetraacetic acid made the type I spermatozoa motile and elevated their respiratory rate. The type II spermatozoa were also immotile and the respiratory rate remained quite low for about 5 min after the dilution. Thereafter, they spontaneously became motile and the respiratory rate increased. The type III spermatozoa became motile upon their dilution and exhibited high respiratory rate. Differences in the motility and respiratory rate of spermatozoa among batches probably result from degree of their maturation. In moving spermatozoa, the ADP and AMP levels increased at the expense of ATP. 2,4-Dinitrophenol elevated the respiratory rate only in immotile spermatozoa, which showed a high ATP level and quite low ADP level, but did not made them motile. Oligomycin inhibited the respiration of both motile and immotile spermatozoa. Probably, the respiratory rate is made low by a shortage of ADP in immotile spermatozoa and is enhanced by ADP production due to the initiation of their movement.     

Genetic analysis of human lymphocyte proteins by two-dimensional gel electrophoresis: 3. Frequent occurrence of genetic variants in some abundant polypeptides of PHA-stimulated peripheral blood lymphocytes

Summary The 100 or so most intensely Coomassie blue-stained polypeptides from PHA-stimulated peripheral blood lymphocytes were analyzed by two-dimensional electrophoresis in combination with family and population studies. Besides polymorphic lymphocyte cytosol 64k polypeptide reported previously, genetic variants were frequently observed in three polypeptides with molecular weights of 100,000, 49,000, and 40,000. All of them occur in the cytosol. These variant polypeptides are charge variants, because they are separated in the isoelectric focusing dimension. It is indicated by family and population studies and cell distribution analysis that the polypeptide with a molecular weight of 100,000 shows a genetic polymorphism determined by two alleles at a new autosomal locus, as described in the following paper. Family and population studies also suggest that a genetic polymorphism defined by alleles at an autosomal locus is present in each of the polypeptides with molecular weights of 49,000 and 40,000. In contrast to the previous reports of the extremely restricted genetic variability of the 100 or so most abundant fibroblast polypeptides, the present data indicate that common genetic variants are present at least in four of the 100 or so most intensely Coomassie blue-stained lymphocyte polypeptides. The result also shows that careful side-by-side comparison of two-dimensional electrophoresis patterns among both parents and their children is an effective method to detect genetic variant polypeptides.     

Cloning of alkaline phosphatase isozyme gene (iap) of Escherichia coli

In Escherichia coli three major alkaline phosphatase isozymes are formed by molecular conversions depending on physiological conditions. A chromosomal gene, iap, is responsible for alkaline phosphatase isozyme conversion and is assumed to code for a proteolytic enzyme removing the arginine residue(s) from the N-terminal position of alkaline phosphatase subunits. A chromosomal fragment which complemented the Iap^? phenotype was cloned into pBR322 by a shotgun method. Transducing phage λiap was constructed in vitro from the chromosomal fragment containing the iap gene and λtna DNA. The integration site of the phage on chromosome was identified as the iap locus by PI transduction, which meant that the cloned chromosomal DNA contained authentic iap gene.The restriction map of the hybrid plasmid was constructed. Based upon this information, several iap deletion plasmids as well as smaller iup⁺ plasmids were constructed. Analysis of the phenotypes conferred by these plasmids enabled us to locate iap gene within a 2-kb segment of the cloned DNA.The cells carrying the iap⁺ plasmid showed very efficient isozyme conversion even in medium containing arginine, an inhibitor for the isozyme conversion. This indicates overproduction of the iap gene product.     

Chromosome segregation in an asymmetrically dividing bacterium,Caulobacter crescentus

The mode of chromosome segregation in an asymmetrically dividing bacterium, Caulobacter crescentus, was studied by examining the fate of labeled DNA strands. Swarmer cells (one type of Caulobacter daughter cell), in which single strands of DNA had been labeled with [³H]thymidine during the previous round of chromosome replication, were grown synchronously in a non-radioactive medium for two generations. The distribution of radioactivity among the cells was visualized by autoradiography under a phase-contrast microscope. The labeled DNA strands in each cell were found to consist of two conserved units. From this, we propose a model in which the swarmer cell has two identical chromosomes, which are segregated into the progeny swarmer cell and the progeny stalked cell after chromosome replication.     

Small circular DNA complexes in eucaryotic cells

A small number of eucaryotic cells (100 to 1000 cells) were pressed by mica sheet; then the extruded contents were adsorbed on mica and processed for electron microscopy. In the absence of divalent cation, small polydisperse circular DNA molecules bound to proteins or membrane material were preferentially adsorbed. The small circular DNA complexes have been found in every eucaryotic cell, primary lymphoid tissue cells of bursa and thymus, primary cell lines of retina and liver, and established cultured cell lines of embryonal teratocarcinoma, F9 and PCC3, HeLa and 3T6. Size distribution of these DNA complexes varies, depending on the cell source. The circles less than 1 μm in contour length predominate in cultured cell lines and the larger ones in primary cell lines and cells in situ. Polydisperse covalently closed circular DNAs were recovered from thymus lymphocytes by the conventional dye-CsCl buoyant density method. Their size distribution was similar to that of the small circular DNA complexes detected by the mica-press-adsorption method. They are present in several tens to hundreds of copies per cell representing, at a maximum, 0.02% of the total cellular DNA. The possibility that small circular DNA complexes may result from gene rearrangement as well as from replicon “misfiring” (A. Varshavsky, 1981, Proc. Nat. Acad. Sci. USA 78, 3673–3677) are discussed.     

Trisomy 12p syndrome

Summary The first case of trisomy of probable 12p mosaicism originated de novo is presented. Comparison of the clinical findings of this patient with those of previously described cases of 12p trisomy derived from translocated chromosomes indicates that the symptoms of 12p trisomy are: (1) normal birth weight and physical development, (2) severe psychomotor retardation and generalized hypotonia, (3) peculiarly round face with prominent cheeks, hypertelorism, epicanthus, broad, flat nasal bridge, short nose with anteverted nostrils, large philtrum, broad, prominent lower lip, and (4) poly(syn)dactyly of feet.