5α-Stigmast-9(11)-en-3β-ol,a sterol from Costus speciosus roots

A new sterol isolated from Costus species roots has been characterized as 5α-stigmast-9(11)-en-3β-ol by spectroscopic data and chemical studies.     

Coenzyme specificity of dehydrogenases and fermentation of pyruvate by clostridia

Summary Four clostridial species (C. pasteurianum, C. butylicum, C. butyricum and C. tetanomorphum) grow on pyruvate. Two other species (C. roseum and C. rubrum) only ferment this compound; this is probably due to their inability to synthesize hexose phosphates from pyruvate (fructose-1,6-diphosphatase and pyruvate carboxylase are absent).The fermentation of pyruvate by the above clostridia yields acetate, carbon dioxide, hydrogen and small amounts of compounds more reduced than acetate. Hydrogen pressure increases the amount of ethanol, butanol and butyrate formed during the fermentation of pyruvate. Since C. roseum and C. rubrum contain a ferredoxin: NADP reductase it seems likely that NADPH₂ is the coenzyme involved in ethanol formation. In accordance with this acetaldehyde and alcohol dehydrogenases exhibit activity with NADPH₂.The glyceraldehyde-3-phosphate dehydrogenase of the clostridia under investigation is NAD specific and so is the -hydroxy-butyryl-CoA dehydrogenase with the exception of C. kluyveri.The specific activity of hydrogenase and the coenzyme specificity of NAD(P) reductase vary among the clostridial species.     

Human α-globin maps to pter-p13.3 in chromosome 16 distal to PGP

Summary Fibroblasts from a fetus with an unbalanced karyotype 46(XY),-16,+(16qter-16p13.3::4q31.1-4qter) were found to possess only one allele at the 3 hypervariable region (3HVR) close to the -globin locus and two alleles at the PGP locus. This places the -globin locus at the very tip of 16p, distal to PGP.     

Union instability and fertility in three Caribbean societies

This paper examines the relationship between sexual union instability and fertility in 3 English-speaking Caribbean societies--Guyana, Jamaica, and Trinidad/Tobago--using data collected in the World Fertility Program. There is usually a positive association between marital stability and fertility, the main reason being that marital instability causes periods of time in which a woman is not sexually active. High levels of divorce and marital separation are likely factors making for lower levels of aggregate fertility. To examine this relationship, this study used an index of cumulative fertility, the duration ratio, that controls for the biological effects of age, and age at 1st union was used as the dependent variable in a multiple regression analysis. The study demonstrated that despite many similarities between the 3 societies, there are also clear differences in terms of how membership in different types of sexual unions interacts with fertility. 1 main conclusion was that there is a positive association between the number of sexual unions and fertility, (in keeping with previous research on these societies). However, the factors were not uniform across the 3 societies. In Guyana marriage had the greatest effect on fertility while in Jamaica the 2 most unstable unions--visiting and common-law--had the greatest effect. In Trinidad/Tobago marriage and common-law had the greatest effect.     

Pathology of black bass hepatic tissue infected with larvae of the tapeworm Proteocephalm ambloplitis

Intra- and interspecific differences in pigmentation between finfold larvae of the three most abundant cyprinids in Dutch eutrophic waters, bream, white bream and roach, were studied, using laboratory-raised larvae in the length range 8–11 mm. Because the internal pigmentation of the larvae has been used for identification, some attention is paid to the effects of different ways of fixation and preservation on transparency. The size and the shape of the melanophores, as described in the literature, could not be used as identification characters because of too much intraspecific variation and the effects of light conditions at the moment of fixation. Three characters proved to be significant for the identification of the larvae of the three species. Roach can be distinguished from bream and white bream by the pattern of melanophores on the belly. A second character is the pigmentation of the ventral aorta, which is only found in white bream. Lastly bream shows an irregular pattern of melanophores on the dorsal side, in contrast to roach which has a regular pattern.     

Vole population dynamics: factors affecting peak densities and amplitudes of annual population fluctuations of<Emphasis Type="Italic">Microtus pennsylvanicus</Emphasis>

We studied factors affecting peak densities and amplitudes of fluctuation during 20 annual population fluctuations ofMicrotus pennsylvanicus Ord, 1815 in alfalfa and bluegrass habitats over a 25-year period. Survival was correlated with population density over the 25 years and was the most consistent variable associated with stoppage of population growth. Although not correlated with population density over the 25 years, a decline in the proportion of reproductively active adult females contributed to cessation of growth of population fluctuations that peaked in late autumn-winter, and to cessation of growth of eight of eleven population fluctuations that peaked during summer-early autumn. We conclude variation in survival to be the primary factor affecting peak densities and amplitudes of population fluctuation ofM. pennsylvanicus.     

Plantlet Regeneration via Multiple Shoot Induction in Indian Cultivars of Lucerne (Medicago sativa L)

An efficient protocol has been developed for in vitro plant regeneration via multiple shoot induction in lucerne (Medicago sativa L). Shoot tips from in vitro grown 5–6 days old seedlings of 3 cultivars, LLC-3, Chetak and RL-88 were used as explants for multiple shoot induction on MS medium supplemented with cytokinins. Maximum of 14 shoots per apical meristem were observed in case of cv Chetak on MS medium supplemented with BAP (12.6 μM) and KN (9.3 μM). Shoot elongation on MS medium supplemented with GA (5.8 μM), while root induction was achieved on MS medium supplemented with IAA (11.4 μM) and activated charcoal (2.0 g l^?1). Tissue raised plants showed 75% survival after transfer to soil under field conditions.     

Paracentric inversions: a review

This review of paracentric inversions in man includes what we know of the behaviour and reproductive consequences of paracentric inversions from other species. Observations of naturally occurring inversions in several species of plants and animals and results of experiments with mutagenically induced inversions in the mouse are discussed. From a review of 184 cases, it is concluded that most of the paracentric inversions in man are harmless and that the risk of heterozygotes having a child with an unbalanced karyotype is low. However, in some cases, it is difficult, if not impossible, to distinguish between a paracentric inversion and a paracentric insertion, the risk in the latter case being about 15%. Caution is also necessary in interpreting the results of prenatal diagnosis for heterozygotes of paracentric inversions, because of the possibility of a variety of unpredictable unbalanced chromosome products.