The malmö polymorphism of coagulation factor IX, an immunologic polymorphism due to dimorphism of residue 148 that is in linkage disequilibrium with two other F.IX polymorphisms

A mouse monoclonal antibody (MAB 9.9) to coagulation factor IX (F.IX) detects a polymorphism in the plasma of normal people. Its epitope has been narrowed down to <6 amino acids in the activation peptide of the X-linked F.IX protein. The activation peptide contains a dimorphism—Thr:Ala—at position 148 of the protein. Using synthetic oligonucleotides, we have demonstrated that (1) the F.IX which reacts with 9.9 has Thr at position 148 and (2) that which does not has Ala. Positive reactors (148^thr) are designated Malmö A, and negative reactors (148^ala) are designated Malmö B. The plasma levels of AA women are indistinguishable from those of A men, and both B men and BB women are null against MAB 9.9. The plasma level of Malmö A in AB women is approximately half that of AA women, and “lyonization” is clearly operating in the heterozygotes. The dimorphism is in strong linkage disequilibrium with two other intragenic RFLPs, TaqI and XmnI. Furthermore, intragenic crossing-over—including double crossing-over—appears to have occurred between the three sites. Seven of the eight possible haplotypes have been identified, five in men and two others in women. The immunoassay that identifies ～50% of the AB women in the pool of Malmö A females with 95% confidence identifies men unambiguously as A or B. The assay would be very useful for population-genetic studies of the Malmö epitope if the studies were limited to men.     

Role of chemical concentration and second carbon sources in acclimation of microbial communities for biodegradation.

A study was conducted to determine the role of concentration of the test chemical, of a second organic compound, and of mutation in the acclimation period before the mineralization of organic compounds in sewage. The acclimation period for the mineralization in sewage of 2 micrograms of 4-nitrophenol (PNP) per liter increased from 6 to 12 days in the presence of 10 mg of 2,4-dinitrophenol per liter. The extension of the acclimation period was equivalent to the time required for mineralization of 2,4-dinitrophenol. In contrast, the time for acclimation for the degradation of 2 micrograms of PNP per liter was reduced when 10 or 100 mg of phenol per liter was added. Lower phenol levels increased the acclimation period to 8 days. The length of the acclimation period for PNP mineralization decreased as the initial concentration of PNP increased from 2 micrograms to 100 mg/liter. The acclimation period for phenol mineralization was lengthened as the phenol concentration increased from 100 to 1,400 mg/liter. The length of the acclimation period for PNP and phenol biodegradation was reproducible, but it varied among replicates for the biodegradation of other nitro-substituted compounds added to sewage or lake water, suggesting that a mutation was responsible for acclimation to these other compounds. The acclimation period may thus reflect the time required for the destruction of toxins, and it also may be affected by the concentration of the test compound or the presence of other substrates.     

Structure and function of Y chromosomal DNA

The sequence organization of four different families of Y chromosomal repetitive DNA is characterized at three levels of spatial extension along the Y chromosome of Drosophila hydei. At the lowest level of resolution, DNA blot analysis of Y chromosomal fragments of different lengths and in situ hybridization experiments on metaphase chromosomes demonstrate the clustering of each particular sequence family within one defined region of the chromosome. At a higher level of resolution, family specific repeats can be detected within these clusters by crosshybridization within 10–20 kb long continuous stretches of cloned DNA in EMBL3 phages. At the highest level of resolution, detailed sequence analysis of representative subclones about 1 kb in length reveals a satellite-like head to tail arrangement of family specific degenerated subrepeats as the building scheme common to all four families. Our results provide the first comparative sequence analysis of three novel families of repetitive DNA on the long arm of the F chromosome of D. hydei. Additional data are presented which support the existence of two related subfamilies of repetitive DNA on the short arm of the Y chromosome.     

The sensitivity of G0-state haemopoietic spleen colony-forming cells to a stimulus for proliferation

Haemopoietic spleen colony-forming units (CFU-s) close to the axis (axial CFU-s) of the long bones have a high probability of self-renewal. They are pluripotent cells and are largely in a G0-State. By contrast, CFU-s close to the bone surface (marginal CFU-s) have a lower probability of self-renewal and are probably more mature, though still pluripotent. Most CFU-s proliferation arises in this zone. As a consequence, marginal CFU-s tend to have shorter G0 histories than do axial CFU-s. Femoral marrow was, therefore, divided into axial and marginal populations and the sensitivity of the CFU-s to an endogenous CFU-s-specific proliferation-stimulating factor was assessed and compared by the tritiated thymidine suicide technique. It was found that axial CFU-s are considerably more resistant to stimulation than are marginal CFU-s in that larger doses for longer periods of exposure are required to increase the proliferative activity of the cells. This behaviour is consistent with the suggestion that cells with a low division probability exist in deeper levels of the quiescent G0-state. Although this hypothesis was developed from the behaviour of cells maintained in culture under sub-optimal physiological conditions, this phenomenon appears, in vivo, to be a characteristic of the stem cell population of haemopoietic tissue; their high resistance to stimulation maintaining the axial CFU-s in a quiescent state.     

Kinetics of mineralization of organic compounds at low concentrations in soil.

The kinetics of mineralization of 14C-labeled phenol and aniline were measured at initial concentrations ranging from 0.32 to 5,000 ng and 0.30 ng to 500 micrograms/g of soil, respectively. Mineralization of phenol at concentrations less than or equal to 32 ng/g of soil and of aniline at all concentrations began immediately, and the curves for the evolution of labeled CO2 were biphasic. The patterns of mineralization of 4.0 ng of 2,4-dichlorophenol per g of soil and 20 ng of nitrilotriacetic acid per g of soil were similar to the patterns for phenol and aniline. The patterns of mineralization of 1.0 to 100 ng of p-nitrophenol and 6.0 ng of benzylamine per g of soil were also biphasic but after a short apparent lag period. The curves of CO2 evolution from higher concentrations of phenol and p-nitrophenol had increasing apparent lag phases and were S-shaped or linear. Cumulative plots of the percentage of substrate converted to CO2 were fit by nonlinear regression to first-order, integrated Monod, logistic, logarithmic, zero-order, three-half-order, and two-compartment models. None of the models of the Monod family provided the curve of best fit to any of the patterns of mineralization. The linear growth form of the three-half-order model provided the best fit for the mineralization of p-nitrophenol, with the exception of the lowest concentrations, and of benzylamine. The two-compartment model provided the best fit for the mineralization of concentrations of phenol below 100 ng/g, of several concentrations of aniline, and of nitrilotriacetic acid. It is concluded that models derived from the Monod equation, including the first-order model, do not adequately describe the kinetics of mineralization of low concentrations of chemicals added to soil.     

Kinetics of mineralization of phenols in lake water.

The kinetics of mineralization of phenol and p-nitrophenol in lake water was determined at concentrations from 200 pg/ml to 5 micrograms/ml. The mineralization data were fit by nonlinear regression to equations for 14 kinetic models that describe patterns of biodegradation by nongrowing cells or by microorganisms growing on either the test chemical or other organic substrates. The kinetics od mineralization of phenol in water samples collected in July was best described by first-order models for 0.5 ng of phenol per ml; by Monod-without-growth, logistic, and logarithmic models for 1.0 and 2.0 ng/ml and 5.0 ng/ml to 1.0 micrograms/ml, respectively, if it is assumed that the mineralizing population uses phenol as the sole carbon source for growth; by models (for phenol at concentrations of 2.0 ng/ml to 1.0 micrograms/ml) that assume that the phenol-mineralizing populations do not grow or grow logarithmically or logistically on uncharacterized carbon compounds but metabolize the phenol when present at levels below and above Km, respectively, for that compound; and by a logarithmic model at 5.0 micrograms/ml. Under the test conditions, usually less than 10% of the phenol C that was metabolized was incorporated into microbial cells or retained by other particulate material in the water at substrate concentrations of 10 ng/ml or less, and the percentage increased at higher substrate concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Carbohydrate side chains of Rauscher leukemia virus envelope glycoproteins are not required to elicit a neutralizing antibody response.

Antisera raised against Rauscher leukemia virus (R-MuLV) contain a preponderance of antibodies against glycoprotein gp70 that are dependent on the presence of carbohydrate side chains for reactivity, as judged by immunoprecipitation or Western blotting. However, the majority of neutralizing antibodies were not dependent on the presence of carbohydrate, as indicated by (i) the ability of deglycosylated R-MuLV to adsorb neutralizing antibody from sera as efficiently as glycosylated R-MuLV and (ii) the ability of deglycosylated R-MuLV to induce neutralizing antibody responses when injected into rabbits. Moreover, a faster response was obtained with deglycosylated R-MuLV than with untreated control virus in the latter experiments. The results indicate that the neutralizing antibodies are a discrete subpopulation of the total antibody response. Furthermore, the carbohydrate moieties appear to afford protection to the virion during infection, rather than serve as a target for neutralization.     

Effect of haemopoietic stem-cell proliferation regulators on early and late spleen colony-forming cells

An inhibitor and stimulator of CFU-s proliferation can be obtained from haemopoietic tissue containing, respectively, relatively quiescent CFU-s (e.g. normal bone marrow) and proliferating CFU-s (e.g. regenerating bone marrow). Their effects on the proliferative behaviour of steady-state and regenerating marrow CFU-s, which produce colonies 7, 10 and 12 days post-transplantation have been investigated. The results demonstrate changing sensitivities of CFU-s to inhibitor and stimulator as they progress through a developmental age structure, 'Older' CFU-s (producing early spleen colonies) are more sensitive to stimulator, 'Younger' CFU-s (producing late spleen colonies) are more sensitive to inhibitor.     

Minimum bacterial density for bacteriophage replication: implications for significance of bacteriophages in natural ecosystems.

Bacteriophage 80 alpha did not increase in number in cultures containing less than about 1.0 X 10(4) to 1.5 X 10(4) CFU of Staphylococcus aureus per ml, but bacteriophage replication did occur when the number of bacteria exceeded this density, either initially or as a result of host cell multiplication. The minimum density of an asporogenous strain of Bacillus subtilis required for an increase in the number of bacteriophage SP beta cI was about 3 X 10(4) CFU/ml. The threshold density of Escherichia coli for the multiplication of bacteriophage T4 was about 7 X 10(3) CFU/ml. In the presence of montmorillonite, bacteriophage T4 did not increase in number until the E. coli population exceeded 10(4) CFU/ml. The mineralization of glucose was not affected in E. coli cultures inoculated with a low number of bacteriophage T4, but it could not be detected in cultures inoculated with a large number of phage. The numbers of bacteriophage T4 and a bacteriophage that lyses Pseudomonas putida declined rapidly after being added to lake water or sewage. We suggest that bacteriophages do not affect the number or activity of bacteria in environments where the density of the host species is below the host cell threshold of about 10(4) CFU/ml.     

Numerical taxonomic analysis of cross-inoculation patterns of legumes and Rhizobium

Summary A survey was made of published results of tests of the capacity of Rhizobium derived from one legume genus to nodulate plants from other genera. The data were derived from more than 14,000 separate cross-inoculation trials involving species from 165 genera of legumes. Numerical taxonomic techniques were applied to 113 of the genera for which results of substantial cross-infection tests were available. The data were examined using mean character difference coefficients re-expressed as total and positive-only similarity coefficients. The resulting similarity matrices were clustered by the unweighted pair-group method using arithmetic averages. Eighteen affinity groups were defined at the 70% similarity level. With few exceptions, the physiological and cultural behavior of the rhizobia was consistent within the defined groups. Two broad categories were suggested in the numerical taxonomic analysis, and their validity is discussed in regard to the geographic, physiological and cultural characteristics of the legumes and their Rhizobium microsymbionts. The taxonomic and agronomic value of this approach and the new groupings are discussed.