Paralogous origin of the rhodopsinlike opsin genes in lizards

Rhodopsinlike opsins constitute a distinct phylogenetic group (Yokoyama 1994, Mol. Biol. Evol. 11:32–39). This RH2 group includes the green-sensitive opsins in chicken and goldfish and the blue-sensitive opsin in a nocturnal lizard gecko. In the present study, we isolated and sequenced the genomic DNA clones for the RH2 opsin gene, rh2 _Ac , of the diurnal lizard Anolis carolinensis. This single-copy gene spans 18.3 kb from start to stop codons, making it the longest opsin gene known in vertebrates. Phylogenetic analysis strongly suggests that rh2 _Ac is more closely related to the chicken green opsin gene than to the gecko blue opsin gene. This gene tree differs from the organismal tree, where the two lizard species should be most closely related, implying that rh2 _Ac and the gecko blue-sensitive opsin genes have been derived from duplicate ancestral genes.Correspondence to: S. Yukiyama     

Numerical simulation of neuronal population coding: influences of noise and tuning width on the coding error

Performance of neuronal population coding is investigated numerically, in neurons with Gaussian tuning functions of various widths and noise ratios. The present model is applicable to both direction coding and orientation coding. It is shown that the coding error exhibits peculiar dependence on the width of the tuning function and that the dependence under the influence of noise is different from that of the noise-free case. In the absence of noise, the coding error increases monotonically with the width of the tuning function. The increment obeys the power law (the exponent estimated is 0.501) when the width is less than the critical value. In this region of the width a scaling law is obtained, which shows that the root-mean-square error is proportional to the square root of the ratio of the width of the tuning function to the population size. When the width exceeds the critical value, the coding error increases more rapidly than the power law. The reason for this anomalous increase, not seen previously, is argued. Existence of noise changes the dependence of the coding error on the width of the tuning function. Unlike the noise-free case, the error under the influence of noise becomes minimum at an intermediate value of the width. The width that gives the minimum coding error is termed the optimum width in this article. The numerical results suggest that the optimum width is roughly proportional to the square root of the noise ratio but has only a weak dependence on the population size. It is further shown that the coding error for the optimum width increases sharply when the noise ratio exceeds about 0.5 and is inversely proportional to the square root of the population size.     

Alcohol and aldehyde dehydrogenase genotypes and drinking behavior of Chinese living in Shanghai

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), the principal enzymes responsible for oxidative metabolism of ethanol, exist in multiple, genetically determined molecular forms. Widely different kinetic properties in some of these isozymes account for the individual differences in alcohol sensitivity. In this study we used the polymerase chain reaction/restriction fragment length polymorphism method to determine the genotypes of the ADH2 and ALDH2 loci of alcoholic and nonalcoholic Chinese living in Shanghai. We also investigated the subjects' drinking patterns by means of semistructured interviews. The alcoholics had significantly lower frequencies of the ADH2² and ALDH2² alleles than did the nonalcoholics, suggesting the inhibitory effects of these alleles for the development of alcoholism. In the nonalcoholic subjects, ADH2² had little, if any, effect, despite the significant effect of the ALDH2² allele in decreasing the alcohol consumption of the individual. Taken together, these results fit the proposed hypothesis for the development of alcoholism, i.e., drinking behavior is greatly influenced by the individual's gentoypes of alcohol-metabolizing enzymes, and the risk of becoming alcoholic is proportionate with the ethanol consumption of the individual.     

Modified cyclic nucleotide systems in Morris hepatoma 3924A favoring expression of cyclic GMP effect.

Modifications in the cyclic nucleotide systems favoring the expression of cyclic GMP effects were found to occur in the transplanted fast-growing Morris hepatoma 3924A. These included: (a) a decreased level of cyclic GMP phosphodiesterase and an increased level of cyclic AMP phosphodiesterase; (b) a disproportionately increased level of cylic GMP-dependent protein kinase relative to that of cyclic AMP-dependent protein kinase; (c) a disproportionately increased level of stimulatory modulator of cyclic AMP-dependent protein kinase relative to that of inhibitory modulator of cyclic AMP-dependent protein kinase; and (d) an increased level of phosphoprotein phosphatase.     

Corn leaf glutamate synthase: Purification and properties of the enzyme

An assay for ferredoxin-glutamate synthase is introduced thatuses an anion exchange resin to isolate the glutamate formedand subsequent determination with the ninhydrin procedure. Theenzyme was purified 200-fold from corn leaves by ammonium sulfatefractionation and chromatography on DEAE-cellulose, DEAE-Sephaceland ferredoxin- Sepharose. The purified enzyme had a specificactivity of 14 µmoles glutamate formed min^–1mg^–1protein. The enzyme has a molecular weight of 160,000. The pHoptimum for catalytic activity is 6.9. The isoelectric pointis at pH 4.2. The apparent Km values of the enzyme for L-glutamine,2-oxoglutarate and ferredoxin are 1,100, 240 and 1.7 µM.The enzyme has a high specificity toward these substrates witha stoichiometry between glutamate formation and glutamine consumption.Sulfhydryl reagents, bathophenanthroline, phthalein acids andazaserine produced strong inhibition of the enzyme activity. ¹Permanent address: Department of Agricultural Chemistry, KyotoUniversity, Kyoto 606, Japan. ²To whom inquiries should be addressed. (Received July 7, 1979; )     

A search for the indianapolis-variant of human alcohol dehydrogenase in liver autopsy samples from North Germany and Japan

Summary Human liver alcohol dehydrogenase (ADH) variants were screened in random autopsy specimens from 53 North German and 34 Japanese individuals. Based on pH-activity profile and electrophoretic pattern, only ADH₂ and ADH₃ variants were detected. In relatively fresh specimens, an anodic band or -ADH band was also observed. The recently reported new molecular forms collectively called ADH_Indianapolis (Bosron et al. 1980) could not be demonstrated and therefore may be confined hitherto only to the American black population.This paper is dedicated to Professor Dr. Dr. H. Baitsch on his 60th birthday     

Studies on Thin-Layer Chromatography after Incubation with [35S]Methionine as an Aid to Identification of Mycobacteria

Thin-layer chromatography (TLC) of ethyl ether-ethanol extracts of mycobacteria obtained after incubation with [³⁵S] methionine is useful for differentiation among mycobacterial species, as the distribution of radioactive spots in TLC shows a characteristic pattern except for a few species, including M. intracellulare and M. gordonae. Some supplementary studies have been carried out in the present investigation and the following results have been obtained.

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Ly-m19: The Lyb-2 region of mouse chromosome 4 controls a new surface alloantigen

Spleen cells from an SJL mouse immunized with 70'/3 cells, an established pre-B cell line, were fused with cells of the nonsecretor myeloma line NS.1. One established hybridoma cell line (clone K10.6) continuously secreted antibody that recognized a new antigenic specificity tentatively named Ly-m19. This newly found antigen is detectable on both T and B cells. Cytotoxicity assays reveal that 75 percent of the spleen and lymph-node cells, 35 percent of bone-marrow cells, and 15 percent of thymus cells reacted with antibody of clone K10.6. Strains expressing the specificity Ly-m19.1 are characterized by negative reactions and include the strains AKR, CE/J, RF/J, GR/A, SJL, P/J, BDP/J, and LG/J. All other strains so far tested are Ly-m19.2. This strain distribution pattern distinguishes Ly-m19 from any known murine lymphocyte alloantigen, but it parallels the Lyb-2 ^c haplotype. Linkage test of a set of AKXL recombinant inbred strains revealed close linkage of Ly-m19 and Lyb-2 loci on mouse chromosome 4.Abbreviations used in this paper LPS lipopolysaccharide - B6 C57BL/6 - Con-A concanavalin A - MLC mixed-lymphocyte culture The prefix m (monoclonal) is used following a suggestion by Klein and co-workers (1979).     

Phlegmacins and anhydrophlegmacinquinones: Dimeric hydroanthracenes from seedlings of Cassia torosa

From seedlings of Cassia torosa four dimeric hydroanthracenes have been isolated. Two, a pair of atropisomeric dimers consisting of two molecules o     

Dammarane saponins of leaves of Panax pseudo-ginseng subsp. himalaicus

From dried leaves of Panax pseudo-ginseng subsp. himalaicus collected in Eastern Himalaya, new dammarane saponins, named pseudo-ginsenosides-F₁₁ and -F₈ were isolated along with the known Ginseng-root saponins, ginsenosides-Rb₃, Rd and -Re. Pseudo-ginsenoside-F₈ was proved to be a mono-acetyl-ginsenoside-Rb₃ and the location of its acetyl group was established mainly by ¹³C NMR spectroscopy. Pseudo-ginsenoside-F₁₁, was identified as the 6-O-α-rhamnopyransyl(1 → 2)-β-glucopyranoside of 3β,6α,12β,25-tetrahydoxy-(20S,24R)-epoxy-dammarane. The C-24 configuration of ocotillone and its related triterpenes was confirmed to be 24R excluding the recent comment by Lavie et al.