Immunoquantitation of aldose reductase in human tissues

Rabbit antibodies raised against bovine kidney aldose reductase (ALR2) were shown to be monospecific for human ALR2 by Western blot analysis of human muscle homogenates. The human enzyme was detected, by reaction with the antiserum (alpha-BKALR2), in homogenates of adrenal gland, muscle, lens, brain, testes, kidney, and placenta, but not in erythrocytes or leukocytes. The amount of enzyme in each tissue was determined by densitometric analysis of autoradiographs of Western blots probed with alpha-BKALR2 and [125I]protein A. Standard curves of radiographic intensity versus amount of purified human muscle ALR2 were linear in the 20 to 200-ng range; a similar sensitivity was seen in tissue homogenates containing up to 675 micrograms total protein. The results presented here for the ALR2 level in human tissues (adrenal greater than muscle greater than lens approximately brain approximately testes greater than kidney approximately placenta) are in agreement with literature values for those tissues from which the enzyme has previously been purified. A notable exception was the absence of detectable ALR2 in human erythrocytes. A quantitative comparison of immunoradiographic response showed that bovine kidney ALR2 was about sevenfold more reactive with a alpha-BKALR2 compared to the human muscle enzyme.     

Aspects of the mineral nutrition of some native British plants — inter-site variation

Fifteen common native British plants were each sampled at a range of sites in Great Britain and green tissues analysed for several inorganic nutrients. Sampling criteria are discussed. The inter-site variation of each element within a species is assessed as a frequency distribution of raw data. Sample values of parameters including arithmetic mean, variance (coefficient of variation), skewness and kurtosis are presented. Their stability is assessed from nitrogen in sub-samples of Pteridium. This suggested sample sizes were adequate but some distributions had sufficient kurtosis to affect the variance. These parameters showed distinctions between macro- and micro-elements and between species. Some mean values sharply distinguished between species and may help to assess current theories of strategy and adaptation but a wider range of species is needed to clarify trends. Coefficients of variation are discussed and were relatively low for a nation-wide survey after allowing for sampling constraints. Coefficients of skewness and kurtosis showed two-thirds of the sample distributions were non-normal. Ecological aspects of the distributions are discussed and are relevant to studies along environmental gradients. Published hypotheses linking positive skewness to stress in the field are considered and two other postulates discussed. Distribution bounds such as those confining 95% of the values are discussed in relation to possible critical levels of nutrients.Nomenclature follows Clapham et al. (1981), Excursion flora of the British Isles. 3rd ed. University Press, Cambridge, except Chamaenerion.     

Phylogeny of Greya (Lepidoptera: Prodoxidae), based on nucleotide sequence variation in mitochondrial cytochrome oxidase I and II: congruence with morphological data

The phylogeny of Greya Busck (Lepidoptera: Prodoxidae) was inferred from nucleotide sequence variation across a 765-bp region in the cytochrome oxidase I and II genes of the mitochondrial genome. Most parsimonious relationships of 25 haplotypes from 16 Greya species and two outgroup genera (Tetragma and Prodoxus) showed substantial congruence with the species relationships indicated by morphological variation. Differences between mitochondrial and morphological trees were found primarily in the positions of two species, G. variabilis and G. pectinifera, and in the branching order of the three major species groups in the genus. Conflicts between the data sets were examined by comparing levels of homoplasy in characters supporting alternative hypotheses. The phylogeny of Greya species suggests that host-plant association at the family level and larval feeding mode are conservative characters. Transition/transversion ratios estimated by reconstruction of nucleotide substitutions on the phylogeny had a range of 2.0-9.3, when different subsets of the phylogeny were used. The decline of this ratio with the increase in maximum sequence divergence among taxa indicates that transitions are masked by transversions along deeper internodes or long branches of the phylogeny. Among transitions, substitutions of A-->G and T-->C outnumbered their reciprocal substitutions by 2-6 times, presumably because of the approximately 4:1 (77%) A+T-bias in nucleotide base composition. Of all transversions, 73%-80% were A<-->T substitutions, 85% of which occurred at third positions of codons; these estimates did not decrease with an increase in maximum sequence divergence of taxa included in the analysis. The high frequency of A<-->T substitutions is either a reflection or an explanation of the 92% A+T bias at third codon positions.      

Stereochemistry of the porphyrin-protein bond of cytochrome c. Stereochemical comparison of Rhodospirillum rubrum, yeast, and horse heart porphyrins c.

Porphyrins c have been obtained from Rhodospirillum rubrum cytochrome c2, yeast cytochrome c, and horse heart cytochrome c and compared using proton magnetic resonance and circular dichroism. Identity of the spectra establishes that chemically and stereochemically the three porphyrins c are identical. Since the stereochemistry of the porphyrin alpha-thioether linkage is not affected in the conversion to porphyrin c, the stereochemistry at the porphyrin alpha-thioether bonds among the corresponding cytochromes c also must be the same. Differences between the proton magnetic resonance of R. rubrum cytochrome c2 and horse heart cytochrome c which were rationalized by invoking an opposite stereochemistry at these condensation sites (Smith, G. M., and Kamen, M. D. (1974), Proc. Natl. Acad. Sci. U.S.A. 71, 4303) must therefore be attributed to other factors.