An analysis of repeated sequence heterogeneity

High-resolution thermal denaturation was used to measure the heterogeneity within repeated DNA sequences. An analysis of combined denaturation/redenaturation experiments on mouse satellite DNA suggests the existence of two minor components, one of which does not appear in the prepared EcoRII monomer. The resolving power of the denaturation/redenaturation experiment is estimated and contrasted with that of the reassociation experiment, often used to estimate repeated sequence heterogeneity. A mathematical model of the redenaturation experiment was developed and applied to mouse satellite data; the results suggest that only one-fourth of the mismatched base pairs are energetically significant in the reduction of heteroduplex stability.     

Haematological studies on wild African elephants (Loxodonta africana)

Various haematological parameters have been measured in a sample of wild African elephants from two game parks in Uganda. The results are compared with those of other authors for the African and Indian elephant and other mammals. No intersex differences were found to occur but calves (1–5 years) differed from the population as a whole in several respects. Some values varied with season and this may be attributed to the effect of dehydration during the dry season. A number of elephants from one of the parks had abnormally high red cell numbers and the possibility is considered that this may reflect an incidence of habitat induced cardiovascular disease.     

Effects of photophase entrainment on mating of the codling moth

Only 25.6% and 15.4% of adult male laboratory-reared diet-fed codling moths, Laspeyresia pomonella (L.), of a Polish strain mated in a field cage when they were reared from egg to adult with regimens of 1800–2400 or 2200–0400 hr darkness, respectively. However, 38.5%, 29.5%, and 29.4% of similar males mated (apple-reared from egg through larva in a 2200–0400 hr dark regime) after shifting the dark regimen in the late 5th instar to 1800–0400, 2200–0400 hr, or continuous dark, respectively.

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Résumé Une souche polonaise de Laspeyresia pomonella est élevée en laboratoire sur aliment artificiel, et soumise, de l'uf à l'adulte, à deux types de régime 1800–2400 h ou 2200–0400 h d'obscurité. Les adultes mâles issus de ces élevages et testés pour l'aptitude à l'accouplement dans des cages en nature, ne s'accouplèrent respectivement que dans la proportion de 25,6% et 15,4%. Toutefois on observe 38,5%, 29,5% et 29,4% d'accouplement avec des mâles comparables provenant d'élevages nourris sur pommes, et selon un régime de 2200–0400 h d'obscurité remplacé au cours du 5ème et dernier stade larvaire par 1800–0400, 2200–0400 h ou par l'obscurité continue.

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Financial support for this investigation was provided by the USDA under PL-480 Project PL-ARS-15 and the International Atomic Energy Agency Contract 13072. Mention of a proprietary product in this paper does not constitute an endorsement of this product by the USDA.     

Muramic Acid Assay in Sediments

An improved chromatographic assay for muramic acid which is sufficiently sensitive for marine sandy sediments is described; it involves acid hydrolysis, thin-layer chromatography, and gas-liquid chromatography.     

Survey of sickle-cell disease in England and Wales.

The incidence and the clinical course of patients suffering from sickle-cell syndrome (Hb SS; Hb SC; Hb S thal) in England and Wales are not known. In 1979 an ad hoc committee was formed to investigate these problems. Initially, a questionnaire was sent to 227 haematologists in England and Wales to determine the number of cases in these countries. The replies have indicated that 1367 cases were seen in 1978 and 1979. Probably this may represent only half the total number of cases. From this survey it has been possible to draw up a composite map showing the location of patients, which has provided a basis to determine the clinical course of the disease, and for further studies into the complications and management of sickle-cell disease in England and Wales. From a second questionnaire preliminary data about the general management and mortality in England and Wales have been recorded.     

Composition, stability and electrolyte permeability of Golgi membranes from lactating-rat mammary gland.

1. Golgi membrane vesicles, isolated from lactating-rat mammary gland and greatly enriched in galactosyltransferase (EC 2.4.1.22), contained over 40 separate bands of protein, including some periodic acid)(Schiff-staining material and free thiol groups, when analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 2. The membrane lipids were enriched in phosphatidylcholine, phosphatidylethanolamine and unesterified cholesterol. 3. Membrane fluidity, as monitored by the fluorescence polarization of 1,6-diphenylhexa-1,3,5-triene, increased linearly over 5-37 degrees C. 4. The vesicle membranes were impermeable to lactose over a wide pH range, but admitted electrolytes of molecular weight below about 300. 5. These properties are discussed with respect to other cellular membranes and the secretion of milk products.