On the Divergence of Alleles in Nested Subsamples from Finite Populations

Within-population variation at the DNA level will rarely be studied by sequencing of loci of randomly chosen individuals. Instead, individuals will usually be chosen for sequencing based on some knowledge of their genotype. Data collected in this way require new sampling theory. Motivated by these observations, we have examined the sampling properties of a finite population model with two mutation processes and with no selection or recombination. One mutation process generates new alleles according to an infinite-alleles model, and the other generates polymorphisms at sites according to an infinite-sites model. A sample of n genes is considered. The stationary distribution of the number of segregating sites in a subsample from one of the allelic classes in the sample conditional on the allelic configuration of the sample is studied. A recursive scheme is developed to compute the moments of this distribution, and it is shown that the distribution is functionally independent of the number of additional alleles in the sample and their respective frequencies in the sample. For the case in which the sample contains only two alleles, the distribution of the number of segregating sites in a subsample containing both alleles conditional on the sample frequencies of the alleles is studied. The results are applied to the analysis of DNA sequences of two alleles found at the Adh locus of Drosophila melanogaster. No significant departure from the neutral model is detected.     

The structure of the basement membrane of human lymph node high endothelial venules: An ultrastructural, histochemical and immunocytochemical study

Summary The structure of the basement membrane of the high endothelium of reactive human lymph nodes was investigated by techniques selective for carbohydrates (periodic acid-Schiff; critical electrolyte concentration staining with Alcian Blue; lectin histochemistry), specific proteins (immunohistochemistry for laminin and fibronectin) and by conventional techniques of light and transmission electron microscopy. Adjacent small lymphocytes were assigned to B and T cell subsets by use of monoclonal antibodies and they were analysed for non-specific esterase,-glucuronidase,-N-acetylglucaminidase and proteolytic activities. The basement membranes were shown to be distinctive and to contain three layers, of differing laminin, glycosaminoglycan and glycoprotein oligosaccharide content. Certain lymphocytes (probably T) contained enzymes potentially able to degrade some components of these basement membranes.     

The relationship between maternal age and chromosome size in autosomal trisomy.

The pattern of maternal age-specific incidence of autosomal trisomy in spontaneous abortions was examined for each chromosome for which a sufficient number of trisomies was observed. This included chromosomes 2, 4, 7-10, 13-16, 18, and 20-22. The rate of increase after age 30 for each of the small chromosomes (groups D-G) was similar, with the exception of chromosome 16, which showed a significantly shallower rate. The C group chromosomes tended to have an intermediate rate of increase after age 30, with the exception of chromosome 7, which had a pattern similar to the smaller chromosomes. The larger chromosomes (2 and 4) had the smallest rate of increase. There was a significant relationship between chromosome size and rate of increase after age 30 (after excluding chromosome 16), but not with rate of increase before age 30. The results suggest that autosomal trisomies may be of heterogeneous origin, with a maternal age-related factor associated with chromosome size and other sources unrelated to chromosome size. Additional evidence for and against this hypothesis is discussed.     

An autosomal dominant form of adolescent multinodular goiter.

Eighteen members of an extended pedigree have been found to have a form of euthyroid adolescent multinodular goiter. Histological examination showed multiple adenomata with areas of epithelial hyperplasia, hemorrhage, and calcification. In two subjects there were focal areas of epithelial hyperplasia reminiscent of low-grade papillary carcinoma, but capsular and vascular invasion was not found. The pattern of inheritance appeared to be autosomal dominant, with diminished penetrance in males. Although the patients were euthyroid, the likely basis for this disorder is an abnormality in thyroglobulin structure and function.     

Polymorphisms of mitochondrially encoded proteins.

Polymorphisms of mitochondrially encoded proteins can be detected in human lymphocytes by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Using an SDS-polyacrylamide 8 M urea system, 17 mitochondrially encoded proteins are distinguishable. Three of these (ME-6, ME-8, and ME-17) were polymorphic among 92 individuals screened, and these polymorphisms are reported here for the first time. With SDS-polyacrylamide electrophoresis without urea, 18 mitochondrial proteins are detectable. One of these (MV-1) varied in two of 31 individuals tested. This polymorphism has been identified previously in HeLa cells. Maternal inheritance of the ME-8 polymorphism was demonstrated by three informative families.     

Evaluation of Diverse Antisera, Conjugates, and Support Media for Detecting Bradyrhizobium japonicum by Indirect Enzyme-Linked Immunosorbent Assay

We evaluated three antisera and four enzyme conjugates for the detection of Bradyrhizobium japonicum by an indirect enzyme-linked immunosorbent assay in microtiter plates. Nitrocellulose membrane sheets were then evaluated as an alternative support medium by using some combinations. Partially purified immunoglobulin G (IgG) or unpurified antisera to strain USDA 110 raised in rabbits, goats, or sheep was reacted in microtiter plates with alkaline phosphatase conjugated to protein A, goat anti-rabbit (GAR), sheep anti-rabbit (SAR), or rabbit anti-goat (RAG) IgG. Cultures or nodules containing homologous rhizobia were detected with equal sensitivity when protein A, GAR, or SAR was reacted with 5 μg of protein IgG per ml or a 1:800 titer of antisera from rabbits, but not goats or sheep. RAG reacted with IgG or antisera from goats or sheep. The detection limit was 2 × 10⁵ rhizobia per well. Rhizobia were spotted on nitrocellulose sheets as an alternative support medium, followed by soaking in 5 μg of protein per ml as IgG and 1:4,000 dilutions of protein A or GAR conjugate. Rhizobia in serogroup 110 were detected with the dye combination Nitro Blue Tetrazolium-5-bromo-4-chloro-3-indolyl phosphate (NBT-BCIP), and rhizobia in serogroup 122 were detected with fast red-naphthol phosphate (FR-NP). At the conclusion of the 5-h assay, purple (NBT-BCIP) or red (FR-NP) spots were visible in positive reactions. The sensitivity of detection was about 1,000 rhizobial cells or 3 μg of nodules tissue.     

Preparation and properties of the water-soluble chlorophyll-bovine serum albumin complexes

By mixing chlorophyll (Chl) a or b with a dense bovine serum albumin solution, the water-soluble Chl-bovine serum albumin complexes were prepared. These complexes, eluted near the void volume on a gel filtration, were separated well from unreacted bovine serum albumin, indicating an aggregation of such molecules in the complexes. Preparation of chlorophyllide (Chlide) a- or Chlide b-bovine serum albumin complex was unsuccessful, while the phytol-, and β-carotene-bovine serum albumin complexes could be obtained. Chls in the Chl-bovine serum albumin complexes had the following characteristics. (i) Main absorption peak of Chl a or b in the red region occurred at 675 nm or 652 nm, respectively. The Chl a-bovine serum albumin complex having absorption peak at 740 nm was also prepared. As compared with the stabilities of Chl a and b in Triton X-100. (ii) Both Chls in the bovine serum albumin-complexes were stable against oxidative stresses, such as photobleaching, Fenton reagent, peroxidase-H₂O₂ system. But (iii) they were easily hydrolyzed by chlorophyllase. These properties of Chls in the bovine serum albumin-complexes were similar to those of Chls in the isolated light-harvesting Chl a/b protein complex. A possible localization of Chls within the bovine serum albumin complexes was suggested that the porphyrin moiety of Chl was buried in bovine serum albumin; however, the hydrophilic edge of porphyrin ring, adjacent to the phytol group, occurred in the hydrophilic region of a bovine serum albumin molecule.     

Chromosomal localization of Emv-16 and Emv-17, two closely linked ecotropic proviruses of RF/J mice.

Emv-16 and Emv-17, the two closely linked ecotropic proviral loci of RF/J mice, have been mapped to chromosome 1 between leaden, ln, and the mouse engrailed homeo-box locus, En-1, by using recombinant inbred strains and conventional backcross analysis.     

Genome organization and nucleotide sequence of human papillomavirus type 33, which is associated with cervical cancer.

The 7,909-nucleotide sequence of human papillomavirus type 33, which is associated with cervical cancer, has been determined and used to deduce the corresponding genome arrangement. Extensive sequence homologies and other genetic features are shared with the related oncogenic virus, human papillomavirus type 16, especially in the major reading frames. A surprising difference was found in the noncoding region of human papillomavirus type 33 as, unlike all other sequenced papillomaviruses, it contains a perfect 78-base pair tandem repeat.