Purification of Avian Myeloblastosis Virus DNA Polymerase by Affinity Chromatography on Polycytidylate-Agarose

Polycytidylic acid [poly(rC)] covalently linked to cyanogen bromide-activated agarose is an effective affinity matrix for the RNA-dependent DNA polymerase from avian myeloblastosis virus. Poly(rC)-agarose is capable of binding large quantities of avian myeloblastosis DNA polymerase, which is then eluted by using a linear KCl gradient of increasing concentration. The DNA polymerase isolated from crude, detergent-disrupted virions by a single pass through columns of poly(rC)-agarose appears nearly homogeneous (approximately 90% pure) as determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. Complete recovery of input enzymatic activity was obtained. Results suggest that polyribonucleotide columns may provide a high-yield, rapid method for the purification of oncornaviral DNA polymerase.     

Genetic polymorphism of human plasminogen.

Using isoelectric focusing (IEF) in polyacrylamide gel of neuraminidase-treated serum or plasma samples and immunofixation or caseinolytic overlay after urokinase activation of gels, a common genetic polymorphism in human plasminogen has been delineated. Two alleles PLGN*A and PLGN*B, were observed with gene frequencies in whites of .69 and .30; in Orientals of .96 and .03; and in blacks of .80 and .18. Several rare alleles were also found. The distribution of phenotypes fits the Hardy-Weinberg equilibrium. Inheritance is autosomal codominant and fits the expectations of Mendelian inheritance. There is fetal synthesis, but no transplacental passage of plasminogen in either direction.     

Linkage relationships among five enzyme-coding gene loci in the copepod Tigriopus californicus: A genetic confirmation of achiasmatic meiosis

Linkage relationships among five polymorphic enzyme-coding gene loci in the marine copepod Tigriopus californicus have been determined using electrophoretic analysis of progeny from laboratory matings. Phosphoglucose isomerase (PGI; EC 5.3.1.9) was found to be tightly linked to glutamate-pyruvate transaminase (GPT; EC 2.6.1.2), with only one recombinant observed in 364 progeny; glutamate-oxaloacetate transaminase (GOT; EC 2.6.1.1) is linked to the PGI-GPT pair, with a recombination fraction of approximately 0.20 in male double heterozygotes. Phosphoglucomutase (PGM; EC 2.7.5.1) and an esterase (EST; EC 3.1.1.1) are not linked to the PGI, GPT, GOT grouping, which has been designated linkage group I. Reciprocal crosses have revealed that no recombination occurs in female T. californicus; this observation confirms a previous report that meiosis in female Tigriopus is achiasmatic.     

Preparation and Properties of Antibodies to GD3 and GM1 Gangliosides

Abstract: Gangliosides G_D3 and G_M1 were coupled to proteins by their car-boxyl groups and antisera were raised against the complexes. Anti-ganglioside antibodies were isolated by affinity chromatography on ganglioside-amino-propyl silica gel columns and the specificity of the antibodies was determined by a quantitative microcomplement fixation assay. Antibodies to G_D3 were highly specific and did not crossreact with G_M3, lactosyl ceramide, or other glycolipids. Purified antibodies to G_M1, in contrast, crossreacted with asialo-G_M1, G_D1b and to a lesser extent, G_M2 and asialo-G_M2. A derivative of G_M1, containing a C-7 sialic acid residue produced by periodate oxidation, reacted with the anti-G_M1 antibodies almost as readily as with G_M1. The specificities of anti-G_M1 antibodies elicited by the covalent ganglioside-protein complexes were similar to those produced by immunization with noncovalent complexes of G_M1 and methylated bovine serum albumin. The ganglioside-protein complexes described here should be useful for preparing antibodies to polysialo-gangliosides that contain neuraminidase-sensitive linkages.     

On the evolutionary significance of Mendel's ratios

Length of time in polymorphism is investigated as a possible evolutionary criterion for Mendel's laws in the case of two alleles at one locus and finite population. Deterministic models with constant and random segregation schemes are investigated. In deterministic models the optimum segregation system depends on the zygotic selection and is Mendelian only in symmetric models. In finite population models the initial gene frequencies interact with the segregation to determine mean time to fixation. In deterministic models with random distortion reduction of the variance of the distortion is more likely to produce polymorphism.     

Noninvolvement of Acyl Carrier Protein with Citrate Synthase and Malate Synthase

Acyl carrier protein (ACP coli) was isolated from commercially grown Escherichia coli B and was acetylated by chemical methods. Biological activity of the synthesized acetyl-ACP coli was checked in an in vitro fatty acid-synthesizing system isolated from E. coli B. Since acetyl-ACP is preferred over acetyl-coenzyme A (CoA) as a substrate in these reactions, the possibility that it may substitute for acetyl-CoA in biosynthetically and oxidatively important cellular pathways (glyoxylate and Krebs cycles, respectively) was examined. Acetyl-ACP was tested for substrate activity with the enzyme of each cycle which has been found to utilize acetyl-CoA. Crystalline citrate synthase (EC 4.1.3.7) of porcine origin (Calbiochem) was found to be inactive with acetyl-ACP coli, which acted neither as a substrate nor as an inhibitor in the presence of acetyl-CoA. Malate synthase (EC 4.1.3.2) of the acetate type was isolated from acetate-grown cells of a mutant of E. coli K-12 (VGD(3)H(5)) and was also found to be inactive with acetyl-ACP coli. The significance of these results and of the recent discovery of another phospho-pantetheine-containing protein are discussed.     

Understanding osteoporosis.

Considerable progress has been achieved recently in our understanding of the normal process by which bone mass is regulated. Age-related trabecular bone loss is characterized not simply by a global loss of bone but also by cortical porosity and loss of trabecular connections. Because bone strength depends on architectural as well as material properties, bone quantity alone cannot define fracture risk with precision. Traditional therapies for osteoporosis increase bone mass, and estrogen therapy, in particular, profoundly decreases fracture risk. The pharmacologic restoration of bone quantity and quality, however, remains elusive. Modern biotechnology offers the hope that progress may come about through the development of growth factors and other osteotropic compounds for clinical use.     

Some aspects of the reproductive biology of the clupeid Ilisha africana (Bloch) off the Lagos Coast, Nigeria

The maturation development, spawning period, oogenesis, fecundity and sex ratio of Ilisha africana off the Lagos Coast, Nigeria were investigated. Six macroscopic and seven microscopic stages of gonad maturity were identified. Maturity was attained at 12.0 cm total length. Breeding occurred throughout the year with the peak spawning between May and December. Oogenesis consisted of seven stages and breeding marks were observed in the species. Fecundity ranged between 2098 and 11 687 eggs. There was a slightly higher correlation between fecundity and weight than between fecundity and length. The egg diameter varied from 0.77 to 1.35 mm. The overall sex ratio was 1 male to 0.97 female. The females however predominated over the males during most months in the peak breeding period.