Flavonoid chemistry of arceuthobium (viscaceae)

Flavonoid compounds from 36 of the 38 known taxa of the genusArceuthobium (dwarf mistletoes) were examined. The flavonoid chemistry of the genus is rather uniform, all taxa producing 3-O-glycosides of the flavonols quercetin and myricetin. No infraspecific chemical variation was encountered, and in those instances where subspecific taxa are recognized, their chemistry was uniform. At the subgeneric level, members of subgenusArceuthobium synthesize primarily glucosides, whereas galactosides are more common in subgenusVaginata. In two of the four Old World species of subgenusArceuthobium (A. juniperi- procerae andA. oxycedri) only myricetin 3-O-glucoside was detected. There are no absolute flavonoid differences between subgenera, sections, or series. On the other hand, flavonoids are useful in several instances at the species level. In several cases, chemical data lend support to the recognition of species which in the past have been considered doubtfully distinct on the basis of morphology.     

A general procedure for the preparation of labeled l-ascorbic acid from labeled d-glucose

A simple, three-step conversion of 1,2-O-isopropylidene-α-d-glucofuranose into l-ascorbic acid, originally described by Bakke and Theander, was used to prepare l-[4-¹⁴C]ascorbic acid from milligram amounts of d-[3-¹⁴C]glucopyranose in 28% radioisotopic yield. In addition, l-[6-¹⁴C]- and l-[U-¹⁴C]-ascorbic acid were prepared from d-[1-¹⁴C]- and d-[U-¹⁴C]-glucopyranose, respectively. The procedure is useful for the synthesis of l-ascorbic acid bearing isotopic hydrogen, carbon, or oxygen atoms at specific positions, subject only to the availability of starting material.     

Variance Component Analysis of Allozyme Frequency Data from Eastern Populations of DROSOPHILA MELANOGASTER

Gene frequency variation at eight polymorphic allozyme loci in Drosophila melanogaster populations in North Carollina and the east coast of the United States were analyzed utilizing the variance component estimation procedures suggested by Cockerham (1969, 1973). These variance components were used to estimate correlations of genes within small geographic regions. The average (over loci) correlation between genes in the same individual within subpopulations was estimated to be 0.033. That between genes in the same subpopulation in different individuals was estimated to be very small, although significantly different from zero. The macrogeographic variation measured by the correlation of genes sampled from the same local region was large for some loci and smaller for others. this variation was also analyzed by correlation with latitude and longitude. Several previously recognized clines were identified as were several new clines.--These results were interpreted as indicating either some degree of nonrandom mating and local breeding unit isolation or a low frequency of null alleles. The geographic and temporal variation has no simple interpretation.     

Linkage of the gene controlling the synthesis of the fourth component of complement to the major histocompatibility complex of the guinea pig

C4-deficient (C4D) guinea pigs are lacking in C4 synthesis, a condition that appears to be caused by a structural gene defect. This defect is inherited as a simple autosomal recessive trait. We have demonstrated linkage between C4D and the major histocompatibility complex of the guinea pig (GPLA). Inbred C4D and inbred strain 13 guinea pigs appear to have the same GPLA haplotype. The use of these two strains should provide an animal model for reconstitution studies of C4 synthesis and for studied exploring the possible role of C4 in cellular and humoral immune responses.Abbreviations used in this paper are C4D deficiency of the fourth component of complement - MHC major histocompatibility complex - GPLA major histocompatibility complex of the guinea pig - MLC mixed lymphocyte culture     

Sex-chromosome aberrations in wood lemmings (Myopus schisticolor)

The wood lemming displays certain peculiar features: (1) The sex ratio shows a prevalence of females (FRANK, 1966; KALELA and OKSALA, 1966), and some females produce only female offspring (KALELA and OKSALA, 1966). (2) In a considerable proportion (in the present material, slightly less than half) of the females, an XY chromosome complement is found in the somatic tissues, but the Y is absent in the germ line of those studied (Fredga et al., 1976). Therefore, (3) a mechanism of double nondisjunction in early fetal life of XY females has to be postulated, which replaces the Y in the germ line by duplication of the X. It is assumed (4) that the X of XY females bears a sex-reversal factor that affects the male determining action of the Y (Fredga et al., 1977). There is (5) a strong presumption that in most cases the XY females are those that produce daughters only, but (6) a few exceptions may occur (FRANK, unpublished observations), suggesting that the regulation according to assumption 3 (perhaps also to 4) is incomplete in XY females. In the present report, four females are described with a 31,XO karyotype, two females with 33,XYY or 32,XY/33,XYY, respectively, two males with a 33,XXY, and one male with a 32,XX/33,XXY karyotype, as observed in a consecutive series of 502 wood lemmings. The incidence of sex-chromosome anomalies in liveborn and adult animals was 2.3%; the overall incidence, including embryos, was 1.79%. Neither the somatic XO constitution nor the existence of an extra Y in females precludes fertility. However, the XXY condition in the male results in sterility. There is certain evidence that an instability of the proposed mechanism for double mitotic nondisjunction of the sex chromosomes in oogonia accounts for the high rate of sex-chromosome aberrations in wood lemmings, at least when the mother is XY.     

Improved chemical synthesis and enzymatic assay of delta-1-pyrroline-5-carboxylic acid.

Δ¹-Pyrroline-5-car?ylic acid, an intermediate in both the biosynthesis and degradation ofl-proline, has been synthesized by the periodate oxidation of hydroxylysine and isolated as a pure compound, as indicated by enzymatic assay with pyrroline-5-car?ylate reductase fromEscherichia coli. Some features of the instability in solution ofΔ¹-pyrroline-5-car?ylic acid have been studied, leading to the conclusion that the rate of decomposition is sensitive to concentration of the compound. Colorimetric assay witho-aminobenzaldehyde was found to be an inadequate measure of the pyrroline compound in partially decomposed solutions.     

Dispersal polymorphisms in subdivided populations

Price's method for analyzing natural selection in subdivided populations is applied to the problem of dispersal polymorphism strategies in a stable habitat. The results agree with the more traditional Mendelian models for this same problem that have recently been published. Further, by using Price's method, the results obtained are simpler and more general, and the causal evolutionary mechanisms underlying the predicted patterns are more easily recognized. The most interesting new result is that the equilibrium proportion of dispersed individuals is a simple function of the risk of dispersing and the regression coefficient of relatedness among individuals who, in the absence of dispersal, would compete for a limited, local resource. This regression coefficient refers to the genotypes that control the dispersal phenotype. For example, when mothers control the phenotype of their progeny, then the regression is from the mother onto an offspring chosen randomly from the local group before dispersal; while when offspring control their own phenotype, the regression is taken directly from offspring onto a randomly chosen cohort member before dispersal. This use of controlling genotypes to calculate regressions explains the form of the parent-offspring conflict over dispersal noted by previous authors. The simplicity and generality of these results suggest that Price's method is a useful approach for studying the class of phenomena known as "games among relatives".