Complotypes in individuals of African origin: frequencies and possible extended MHC haplotypes

We analyzed the frequency distribution of 106 complotypes [four allele sets of the major histocompatibility complex (MHC) genes for the complement proteins factor B, C2, C4A, and C4B] from 32 Black families residing in Boston and Washington, DC. Twenty-five different complotypes were identified, among which there were four complotypes that had not been previously observed in our large database of complotypes compiled from family studies of Boston Caucasians and that are, presumably, unique to individuals of African origin. These four African-derived complotypes areFC(1,90)0, FC63, S1C2,17, andSC(3,2,90)0. The frequencies of two of these four unique Black complotypes,FC(1,90)0 andFC63, were increased significantly when compared to Caucasians (p_corr <0.00042, p_corr=0.00294, respectively). The complotypeFC(1,90)0 was in positive linkage disequilibrium withHLA-DR3 haplotypes containing theB locus antigens Bw42, Bw52, Bw53, and Bw58, whileFC63 was associated withHLA-Bw70,-DR5. These findings demonstrate the extensive polymorphism of complotypes in Blacks, and also suggest that it may be possible to define unique extended haplotypes of African origin.     

In vitro multiplication in liquid culture of Syngonium contaminated with Bacillus spp. and Rathayibacter tritici

Contaminated Syngonium clusters were multiplied in an air lift bioreactor in liquid medium containing sucrose with the medium being circulated through a sterilizing filter. After 30 days, the culture in filtered medium produced 19.5 shoot initials per gram fresh weight of inoculum compared to 8.7 shoot initials produced in unfiltered medium. Transfer to an elongation medium with 30 mg l^-1 Rifampicin produced shoots on 67% of the clusters, while transfer to elongation medium without Rifampicin poduced shoots on 40% of the clusters. Clusters grown for three subcultures in a reactor without medium filtration had lost their multiplication ability. Clusters grown for three subcultures in a reactor with filtration, however, continued to show a two-three fold increase in fresh weight and shoot production.Abbreviations MS Murashige and Skoog     

Human C4 haplotypes with duplicated C4A or C4B

In the course of study of families for the sixth chromosome markers HLA-A, C, B, D/DR, BF, and C2, the two loci for C4, C4A, and C4B, and glyoxalase I, we encountered five examples of probable duplication of one or the other of the two loci for C4. In one of these, both parents and one sib expressed two different structural genes for C4B, one sib expressed one, and one sib expressed none, suggesting that two C4B alleles were carried on a single haplotype: HLA-A2, B7, DR3, BFS1, C2C, C4A2, C4B1, C4B2, GLO1. In a second case, two siblings inherited C4B*1 and C4B*2 from one parent and C4B*Q0 from the other. This duplication appeared on the chromosome as HLA-AW33, B14, DR1, BFS, C2C, C4A2, C4B1, C4B2, GLO2. In a third, very large family with 3 generations, a duplication of the C4B locus occurred which was followed in 2 generations. In one individual, there were three C4B alleles and two C4A alleles. One of the C4B alleles had a hemolytically active product with electrophoretic mobility near C4B2 and was designated C4B*22. It segregated with C4B1 in the family studied. The complete haplotype was HLA-A11, CW1, BW56, DR5, BFS, C2C, C4A3, C4B22, C4B1, GLO2. In another family with 12 siblings, one parent and eight children expressed two C4A alleles on the haplotype HLA-AW30, BW38, DR1, BFF, C2C, C4A3, C4A2, C4BQ0, GLO1.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mapping of the structural gene for the second component of complement with respect to the human major histocompatibility complex.

Families have been HLA typed, and allotypes of the second component of complement and properdin factor B determined. The lod score for the C2 structural gene and HLA-B from the study of 11 families and 55 informative meioses was 14.39 at maximum likelihood estimate of the recombination fraction of .02. This is related to other estimates of the distance between these two genes. The relative kinetic activities of the C2 allotypes were studied and no differences were demonstrated. No crossovers between Bf and C2 were observed.