Fragile sites,chromosome evolution,and human neoplasia

Summary In a study of the possible relationship between human fragile sites, chromosomal rearrangements related to neoplasia, and chromosome regions involved in evolutionary changes, we have found that 17 fragile sites related to cancer, 15 fragile sites not related to cancer, and 17 non-fragile regions also related to human malignancy correspond or are close to bands involved in rearrangements that have taken place during chromosomal evolution in primates.     

The structure and evolution of the spider monkey delta-globin gene

We have isolated the delta-globin gene of the New-World spider monkey, Ateles geoffroyi, and compared its nucleotide sequence with those of other primate delta- and beta-globin genes. Among primate delta-globin genes, the rate of nonsynonymous substitutions is much less than the rate of synonymous substitutions. This suggests that primate delta- globin genes may remain under evolutionary conservation, perhaps because hemoglobin A2 has an as yet unknown physiological importance.      

Biochemical pathways in prokaryotes can be traced backward through evolutionary time

For the first time, a credible prokaryotic phylogenetic tree is being assembled by Woese and others using quantitative sequence analysis of oligonucleotides in the highly conservative rRNA. This provides an evolutionary scale against which the evolutionary steps that led to the arrangement and regulation of contemporary biochemical pathways can be measured. This paper presents an emerging evolutionary picture of aromatic amino acid biosynthesis within a large superfamily assemblage of prokaryotes that is sufficiently developed to illustrate a new perspective that will be applicable to many other biochemical pathways.      

Multiple forms of lactate dehydrogenase in Staphylococcus aureus

Activities for nicotinamide adenine dinucleotide (NAD)-dependent and NAD-independent forms of lactate dehydrogenase (LDH) were measured in cell-free extracts of Staphylococcus aureus strain PS 6 for the d and l isomers of lactate. Data obtained for the NAD-dependent lactate dehydrogenases indicate that oxidation of both isomers of lactate is due to both an l-lactate-specific LDH and a lactate racemase. After acrylamide gel electrophoresis, two bands exhibiting LDH activity were detected in crude or in partially purified cell-free extracts. The fast band exhibited LDH activity that was not NAD-dependent for both isomers of lactate, whereas, the slow band had very high NAD-dependent LDH activity for the l isomer but just detectable activity or the d isomer. Both bands appeared when d-lactate was used as the substrate, but only the slow band was formed when l-lactate was the substrate. NAD-dependent LDH, in apparent association with a nonspecific tetrazolium-reducing protein, is responsible for the production of the slow band.     

Instrumental assay of microbial lipase at constant pH

A rapid, accurate method with high sensitivity and reproducibility, and having the advantage of a short incubation period under constant pH, has been developed for routine measurement of microbial lipase. Assembled from readily available and economical instrumental components, the apparatus includes a pH meter, a thermoelectric heating and stirring device, a motor-driven burette, and an automatic recorder. The reaction mixture, consisting of 5 ml of a 10% olive oil-gum arabic emulsion, 2 ml of 3 m NaCl, 2 ml of sodium taurocholate (15 mg/ml) of 0.075 m CaCl(2), 5 ml of water, and 1 ml of enzyme solution, was adjusted to pH 8.0 and 37 C. The pH was maintained at a constant value by automatic addition of 0.01 n NaOH during the incubation period, which usually lasted 5 min. A lipase unit, derived from the use of this technique, may be defined as the number of microequivalents of acid liberated per minute under the specified conditions. The method was sensitive to 0.01 units. Various organisms tested produced 0.17 to 1.32 units per ml of the cell filtrate. An Arrhenius plot for staphylococcal lipase yielded 14,500 cal for function A (energy of activation).     

Nephelometric Assay of Bovine Antistaphylocoagulase Serum

A nephelometric assay of staphylococcal coagulase has been utilized to measure coagulase inhibition by bovine anticoagulase serum. Suitably diluted antisera produced maximal inhibition when incubated with purified coagulase at pH 7.3 in phosphate-buffered saline for 15 min at 22 C or 1 hr at 4 C. Neutralization of coagulase activity was measured as the reduction in the clotting rate of a fibrinogen-plasma substrate, and was directly proportional to the concentration of antiserum over a wide range of coagulase activity. A unit of anticoagulase was defined as the amount of inhibitor that neutralized one unit of coagulase. In addition to the heat-stable (56 C, 30 min) antibody contained in the crude gamma-globulin fraction, a heat-labile, nondialyzable coagulase inhibitor was also detected in the sera from 15 of 16 randomly selected dairy cows.     

The evolutionary history of the amylase multigene family in Drosophila pseudoobscura

In Drosophila pseudoobscura, the amylase (Amy) multigene family is contained within a series of inversions, or gene arrangements, on the third chromosome. The Standard (ST), Santa Cruz (SC), and Tree Line (TL) inversions are central to the phylogeny of arrangements, and have clusters of other arrangements derived from them. The gene arrangements belonging to each of these three clusters have a characteristic number of Amy genes, ranging from three in ST to two in SC to one in TL. This distribution pattern can reflect a history of either duplications or deletions, although the data available in the past did not permit a decision between these alternatives. We provide unambiguous evidence that three Amy genes were present before the divergence of the ST, SC, and TL arrangements. Thus, the current status of the Amy multigene family is the result of deletions in the TL and SC arrangements, which created three new pseudogenes: TL Amy2-psi, TL Amy3-psi, and SC Amy3- psi. Analysis of pseudogene sequences revealed that, in the SC and ST arrangements, pseudogene evolution has been retarded, most likely due to the homogenization effect of gene conversion. Finally, by determining the original copy number, we have reconstructed the evolutionary history of the Amy multigene family and linked it with the evolution of the central gene arrangements.      

Exploring the legacy of African and Indigenous Caribbean admixture in Puerto Rico

Objectives

From an anthropological genetic perspective, little is known about the ethnogenesis of African descendants in Puerto Rico. Furthermore, historical interactions between Indigenous Caribbean and African descendant peoples that may be reflected in the ancestry of contemporary populations are understudied. Given this dearth of genetic research and the precedence for Afro-Indigenous interactions documented by historical, archeological, and other lines of evidence, we sought to assess the biogeographic origins of African descendant Puerto Ricans and to query the potential for Indigenous ancestry within this community.

Materials and Methods

Saliva samples were collected from 58 self-identified African descendant Puerto Ricans residing in Puerto Rico. We sequenced whole mitochondrial genomes and genotyped Y chromosome haplogroups for each male individual (n = 25). Summary statistics, comparative analyses, and network analysis were used to assess diversity and variation in haplogroup distribution between the sample and comparative populations.

Results

As indicated by mitochondrial haplogroups, 66% had African, 5% had European, and 29% had Indigenous American matrilines. Along the Y chromosome, 52% had African, 28% had Western European, 16% had Eurasian, and, notably, 4% had Indigenous American patrilines. Both mitochondrial and Y chromosome haplogroup frequencies were significantly different from several comparative populations.

Discussion

Biogeographic origins are consistent with historical accounts of African, Indigenous American, and European ancestry. However, this first report of Indigenous American paternal ancestry in Puerto Rico suggests distinctive features within African descendant communities on the island. Future studies expanding sampling and incorporating higher resolution genetic markers are necessary to more fully understand African descendant history in Puerto Rico.     

USE OF SENSORY EVALUATION FOR MEASURING DEODORIZING EFFECTS OF AN AIR CONDITIONER

The application of sensory methodology for measuring deodorizing effect of an air conditioner equipped with electric plasma was introduced. Deodorizing effect was measured using chemical and sensory methods at different time (0, 30 and 60 min) and mode (control, blowing and cooling) of an air conditioner. Smoke from a roll of cigarette in a closed room was used as a source of odor and the concentrations of acetic acid and ammonia were measured as odorous chemical components. As one of the sensory methods triangle test was used and as a first step to obtain deodorizing effects by triangle test, the threshold of each panelist was obtained as the log dilution ratio of odor concentration at which the difference from odorless air was detected. The odor concentration at each time and mode was calculated using the threshold of the panel and the deodorizing effect was obtained on the basis of the odor concentration. In addition to a triangle test, scaling methods such as category scaling or magnitude estimation were used to measure deodorizing effect of an air conditioner. Deodorizing effects by scaling methods were calculated based on odor intensity with time at each mode. The regression analysis was done between the efficacy of deodorizing effect by sensory test and those by acetic acid and ammonia, the R² values of the regression equations for triangle test, category scale, and magnitude estimation were 0.84, 0.72 and 0.69, respectively. Deodorizing effect by triangle test explained the decrease of acetic acid and ammonia better than those by category scaling or magnitude estimation while high cost and time consuming labor involved in triangle tests reduced the merit. The results of this study demonstrated that various sensory methods could be used to measure deodorizing effect of air conditioners and further researches on fast and reliable methods are needed to establish the official procedures.