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.      

Selection for high-level chloroquine resistance results in deamplification of the pfmdr1 gene and increased sensitivity to mefloquine in Plasmodium falciparum.

A chloroquine resistant cloned isolate of Plasmodium falciparum, FAC8, which carries an amplification in the pfmdr1 gene was selected for high-level chloroquine resistance, resulting in a cell line resistant to a 10-fold higher concentration of chloroquine. These cells were found to have lost the amplification in pfmdr1 and to no longer over-produce the protein product termed P-glycoprotein homologue 1 (Pgh1). The pfmdr1 gene from this highly resistant cell line was not found to encode any amino acid changes that would account for increased resistance. Verapamil, which reverses chloroquine resistance in FAC8, also reversed high-level chloroquine resistance. Furthermore, verapamil caused a biphasic reversal of chloroquine resistance as the high-level resistance was very sensitive to low amounts of verapamil. These data suggest that over-expression of the P-glycoprotein homologue is incompatible with high levels of chloroquine resistance. In order to show that these results were applicable to other chloroquine selected lines, two additional mutants were selected for resistance to high levels of chloroquine. In both cases they were found to deamplify pfmdr1. Interestingly, while the level of chloroquine resistance of these mutants increased, they became more sensitive to mefloquine. This suggests a linkage between the copy number of the pfmdr1 gene and the level of chloroquine and mefloquine resistance.     

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.      

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.      

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.     

1H NMR of glycosaminoglycans and hyaluronic acid oligosaccharides in aqueous solution: the amide proton environment

The exchangeable amide protons of hyaluronic acid (HA) oligosaccharides and a higher-molecular-weight segment dissolved in H2O at pH 2.5 or 5.5 were examined by H NMR spectroscopy at 250 MHz. The HA segment preparation showed a single amide resonance, near the chemical shift for the amide proton of the monosaccharide 2-acetamido-2-deoxy-beta-D-glucopyranose (beta-GlcNAc). Smaller HA oligosaccharides showed two or three separate amide proton resonances, corresponding in relative peak area to interior or end GlcNAc residues. The interior GlcNAc amide resonance occurred at the same chemical shift as the single resonance of the HA segment. For the end GlcNAc residues, linkage to D-glucuronopyranose (GlcUA) through C1 resulted in an upfield shift relative to the beta-anomer of GlcNAc, whereas linkage through C3 resulted in a downfield shift relative to the corresponding anomer of GlcNAc. These chemical-shift perturbations appeared to be approximately offsetting in the case of linkage at both positions. The amide proton vicinal coupling constant (ca. 9 Hz) was found to be essentially independent of chain length, residue position, or solution pH. These data favor a nearly perpendicular orientation for the acetamido group with respect to the sugar ring, little affected by linkage of GlcNAc to GlcUA. No evidence for the existence of a stable hydrogen bond linking the amide proton with the carboxyl(ate) oxygen of the adjacent uronic acid residue was found. The amide proton resonances for chondroitin, chondroitin 4-sulfate, and dermatan sulfate were compared to that of HA. The chemical shifts of these resonances deviated no more than 0.1 ppm from that of HA. A small dependence on the identity of the adjacent uronic acid residue was noted, based on the observation of two resonances for dermatan sulfate.     

The expression of Plasmodium falciparum bloodstage antigens in Escherichia coli

A library of cDNA clones expressing proteins of the asexual blood stages of a Papua New Guinean isolate of Plasmodium falciparum (isolate FCQ27/PNG (FC27] was constructed in the bacteriophage vector lambda gt11-Amp3. In an in situ colony immunoassay, human serum was used to identify colonies producing natural immunogens. Sera from donors of defined clinical status, or reactive to a defined subset of natural immunogens were used to identify clones of particular interest (for example, clones reacting with convalescent but not with acute serum or clones expressing the isolate specific S-antigen of FC27). Antisera raised by immunizing mice and rabbits with cloned antigens were used to characterize the P. falciparum proteins corresponding to the antigen-positive clones. Nucleotide sequence analysis of an antigen found on the surface of cells infected with ring stage parasites revealed an unusual sequence coding for eight, four and three amino acid repeats rich in acidic amino acids. The discussion centres on the use of cloned antigens as tools for the analysis of the host-protective immune response and selection of candidate vaccine molecules.     

Amino Acid Requirements and Proteolytic Activity of Streptococcus sanguis

The growth response of Streptococcus sanguis groups 1:A and 1:B in a complete chemically defined medium was not influenced by the oxygen concentration of the growth atmosphere. All of the cultures required cysteine and arginine; tyrosine and branched-chain amino acids were frequently required. Proteolysis of casein, mucin, and the anionic proteins of germfree rat saliva by S. sanguis was demonstrated. Hydrolytic activity toward casein was found in the soluble contents of the cells and in the cellular debris after disruption of the cells, with the soluble fractions exhibiting greater proteolytic activity toward casein. The soluble fractions from S. sanguis did not hydrolyze mucin, but this substrate was hydrolyzed by the cell debris fraction. When the amino acid requirements and proteolytic activity of S. sanguis and S. mutans were compared, these two oral streptococcal species exhibited distinct and characteristic differences.     

Vicariance across major marine biogeographic barriers: temporal concordance and the relative intensity of hard versus soft barriers

The marine tropics contain five major biogeographic regions (East Pacific, Atlantic, Indian Ocean, Indo-Australian Archipelago (IAA) and Central Pacific). These regions are separated by both hard and soft barriers. Reconstructing ancestral vicariance, we evaluate the extent of temporal concordance in vicariance events across three major barriers (Terminal Tethyan Event (TTE), Isthmus of Panama (IOP), East Pacific Barrier, EPB) and two incomplete barriers (either side of the IAA) for the Labridae, Pomacentridae and Chaetodontidae. We found a marked lack of temporal congruence within and among the three fish families in vicariance events associated with the EPB, TTE and IOP. Vicariance across hard barriers separating the Atlantic and Indo-Pacific (TTE, IOP) is temporally diffuse, with many vicariance events preceding barrier formation. In marked contrast, soft barriers either side of the IAA hotspot support tightly concordant vicariance events (2.5 Myr on Indian Ocean side; 6 Myr on Central Pacific side). Temporal concordance in vicariance points to large-scale temporally restricted gene flow during the Late Miocene and Pliocene. Despite different and often complex histories, both hard and soft barriers have comparably strong effects on the evolution of coral reef taxa.