Nucleotide sequence divergence among DNA fractions of different syngens of Tetrahymena pyriformis

The magnitude of the differences in base sequence of DNA fractions derived from different syngens of the ciliated protozoan Tetrahymena pyriformis was investigated. Each DNA was fractionated into unique and repeated sequences by hydroxylapatite chromatography, and the fractions were tested by in vitro molecular hybridization techniques. The amount of hybrid formed and the thermal stability of the hybrid molecules were examined at different incubation temperatures (50 and 65 C) for unique sequences and at 50 C for repeated sequences. The extent of the reactions involving either unique or repeated sequences was nearly complete when the two DNAs compared were derived from the same syngen. Moreover, intrasyngenic hybrids formed at 50 C (and 65 C for unique sequences) exhibit a high degree of thermal stability. In contrast, the extent of the reactions involving sequences derived from different syngens was low, as expected from the effect of mismatching on rate of reassociation, and intersyngenic hybrids formed at 50 C have low thermal stability. The reaction of unique sequences is further reduced at 65 C and the intersyngenic hybrids formed have a higher thermal stability than those formed at 50 C. The degree to which thermal stability is lowered was then used to estimate the percentage of mispaired bases. The average divergence of unique sequences between syngens is large and of the magnitude found for rodent DNAs from different genera or for Drosophila DNAs from nonsibling species. The repeated sequence fraction may contain more than one component and may be more conserved than the unique sequence fraction.     

Methodological considerations in the study of population density and social pathology

A previous study of the effects of overcrowding on social behavior is discussed and replicated in this article. Consideration of two major methodological problems — the construction of the class and ethnicity indices and the measurement of social class — leads to reanalysis of the data and to results differing in several significant respects from the original results. Although these new results do not provide a definitive answer to the question of the effects of population density on social pathologies, they do show that studies of the problem are subject to several, possibly severe, measurement problems. Until these are more adequately dealt with, conclusions regarding the relation between density and human behavior must be both cautious and tentative.     

Micro Indirect Hemagglutination Test for Cytomegalovirus

In an effort to obtain the flexibility and ease of performance of a rapid, serological test for detection of cytomegalovirus antibody, the indirect hemagglutination (IHA) technique was investigated by using a microserological system. Antigens were prepared from tissue cultures of infected human fibroblasts. The specificity of the cytomegalovirus antibody response detected by the IHA test correlated well with the standard neutralization test. The IHA method was more sensitive than the complement fixation test in detecting antibody in congenitally infected newborns. There appeared to be some heterologous antibody response with Herpesvirus hominis or varicella virus infections. The IHA test pattern was found to be very stable with excellent persistence of agglutination.     

Large scale separation of protease inhibitors from malignant human breast tissue

Summary ₁-Antitrypsin was isolated as an electrophoretically homogeneous protein in preparative quantities from malignant human breast tissue by a two-step procedure of affinity chromatography on Sepharose-chymotrypsin, followed by polyacrylamide gel electrophoresis. Additionally, ₂-macroglobulin and ₁-antichymotrypsin were bound to, and subsequently eluted from the column. Antithrombin III and ₁-acid glycoprotein, which were also components of the tissue extracts, were not bound, and appeared in the breakthrough peak. ₁-Antitrypsin appeared to be partially modified immunologically by Sepharose-chymotryppin chromatography. However, ₂-macroglobulin remained immunologically unaltered. Upon subsequent polyacrylamide gel electrophoresis, the ₁-antitrypsin regained its capacity to give an immunological reaction of complete identity. Inhibitory activity toward proteases is also observed in filtrates of 1000 molecular weight cut-off membrane filters. Endogenous caseinolytic activity was observed in several eluate fractions. However, only N-benzoyl-L-tyrosine-ethyl ester, of the model compounds tested, was cleaved. The esterase activity is attributed to a breast tissue component since the column was free from dissociable chymotrypsin. Affinity chromatography on Sepharose-chymotrypsin represents a means of rapidly separating 37.5% of the total antichymotryptic activity from breast tissue extracts in high purity, in a single step.     

Adaptation at Specific Loci. IV. Differential Mating Success among Glycolytic Allozyme Genotypes of Colias Butterflies

Male mating success as a function of genotype is an important fitness component. It can be studied in wild populations, in species for which a given group of progeny has exactly one father, by determining genotypes of wildcaught mothers and of sufficient numbers of their progeny. Here, we study male mating success as a function of allozyme genotype at two glycolytic loci in Colias butterflies, in which sperm precedence is complete, so that the most recent male to mate fathers all of a female's subsequent progeny.--For the phosphoglucose isomerase, PGI, polymorphism, we predict mating advantage and disadvantage of male genotypes based on evaluation of their biochemical functional differences in the context of thermal-physiological-ecological constraints on the insects' flight activity. As predicted, we find major, significant advantage in mating success for kinetically favored genotypes, compared to the genotype distribution of males active with the sampled females in the wild. These effects are repeatable among samples and on different semispecies' genetic backgrounds.--Initial study of the phosphoglucomutase, PGM, polymorphism in the same samples reveals heterozygote advantage in male-mating success, compared to males active with the females sampled. This contrasts with a lack of correspondence between PGI and PGM genotypes in other fitness index or component differences.--Epistatic interactions in mating success between the two loci are absent.--There is no evidence for segregation distortion associated with the alleles of either primary locus studied, nor is there significant assortative mating.--These results extend our understanding of the specific variation studied and suggest that even loci closely related in function may have distinctive experience of evolutionary forces. Implications of the specificity of the effects seen are briefly discussed.     

A bacteriological investigation of the effectiveness of cleaning and disinfection procedures for toilet hygiene

S cott , E. & B loomfield , S.F. 1985. A bacteriological investigation of the effectiveness of cleaning and disinfection procedures for toilet hygiene, Journal of Applied Bacteriology 59 , 291–297.
The bacterial contamination of hospital and institutional toilets and toilet areas which were cleaned daily was investigated. The effect of daily disinfection with hypochlorite or a quaternary ammonium product, or with a continuous-release hypochlorite disinfectant system, based on the chlorine-releasing agent trichloro-isocyanuric acid, was determined. The continuous release system produced substantial and sustained reduction in contamination of the toilet itself (water, toilet bowl and rim) and some reduction in contamination of sites surrounding the toilet (seat, floor, and air). By contrast, although daily disinfection produced some reduction in contamination compared with daily cleaning, the reductions were less than that associated with the continuous release system and indicated the inadequacy of daily disinfection and/or cleaning for toilets where effective procedures are required.     

Chlorophyll-protein complexes from higher plants: A procedure for improved stability and fractionation

An improved procedure for the electrophoretic fractionation of higher plant chlorophyllprotein complexes is described. Compared with currently used systems, it greatly reduces the amount of chlorophyll that is found unassociated with protein after electrophoresis and resolves four chlorophyll-protein complexes. The slowest migrating band has a red adsorption maximum at 674 nm or greater, contains chlorophyll a but not chlorophyll b, and has a molecular weight equivalency of 110,000. These properties are similar to the previously described CPI or P700-chlorophyll a-protein complex. The amount of the total chlorophyll in this material is increased by two to three fold over that present in the equivalent complex fractionated by previous procedures. The other three chlorophyll-protein complexes contain both chlorophylls a and b, and have molecular weight equivalencies of 80,000, 60,000, and 46,000. None of these complexes seems to correspond directly to the previously characterized light-harvesting chlorophyll $\text{a}\text{b}$-protein complex.     

Kloeckera apis st. nov.; the imperfect state of Hanseniaspora guilliermondii Pijper

K. apiculata var. apis (nom. nud.) was found to be the imperfect state of H. guilliermondii Pijper by a high degree of DNA reassociation. The name is validated and raised to species rank, K. apis Lavie ex Smith, Simione and Meyer. K. apis and H. guilliermondii could be distinguished from H. uvarum and H. valbyensis by a low DNA reassociation and by growth at 37 C.DNA studies performed at the ATCC were supported in part by Public Health Service grant GM 19240-05.