Eight highly polymorphic microsatellite markers for the army ant Eciton burchellii

The army ant Eciton burchellii is a nomadic predator in the rain forests of Central and South America. Detailed work has documented many aspects of this species’ ecology, behaviour and life history. However, a detailed investigation into within colony relatedness structure requires the development of genetic tools. Here we present eight microsatellite markers with between nine and 25 alleles. For each loci there is close agreement between observed and expected heterozygosity.     

Poverty or income inequality as predictor of mortality: longitudinal cohort study.

OBJECTIVE: To determine the effect of inequality in income between communities independent of household income on individual all cause mortality in the United States. DESIGN: Longitudinal cohort study. SUBJECTS: A nationally representative sample of 14,407 people aged 25-74 years in the United States from the first national health and nutrition examination survey. SETTING: Subjects were followed from initial interview in 1971-5 until 1987. Complete follow up information was available for 92.2% of the sample. MAIN OUTCOME MEASURES: Relation between both household income and income inequality in community of residence and individual all cause mortality at follow up was examined with Cox proportional hazards survival analysis. RESULTS: Community income inequality showed a significant association with subsequent community mortality, and with individual mortality after adjustment for age, sex, and mean income in the community of residence. After adjustment for individual household income, however, the association with mortality was lost. CONCLUSIONS: In this nationally representative American sample, family income, but not community income inequality, independently predicts mortality. Previously reported ecological associations between income inequality and mortality may reflect confounding between individual family income and mortality.     

Effects of lead on luteal function in rhesus monkeys

Exposure to lead in the workplace or home environment has been implicated as a cause of decreased fertility in women. In a previous study, as part of our effort to determine effects of lead in primates, female rhesus monkeys were exposed to lead acetate in drinking water (n = 10) or provided water with no added lead (n = 7) for 33 mo. Lead was administered at levels between 2 and 8 mg/kg/day, with doses adjusted to keep blood lead values near a target of 70 micrograms/dl (observed mean +/- SEM = 68.9 +/- 6.54 micrograms/dl). Blood lead concentrations in control animals were less than 10 micrograms/dl. No significant differences were detected between control and experimental animals in body weight, hematocrit, or general health. Female monkeys receiving lead exhibited longer and more variable menstrual cycles and shorter menstrual flow. In the present study, circulating amounts of progesterone (P4) were determined to evaluate luteal function during the final 7 mo of treatment with lead. Several characteristics were altered as a result of lead treatment: circulating amounts of P4 were reduced as indicated by relative units of area under the concentration-time curve, maximal amounts of P4 were reduced, and P4 levels were greater than 1 ng/ml on fewer days. There were no significant differences between groups in mean percent of anovulatory cycles. Therefore, although chronic treatment with the levels of lead used in this study did not prevent ovulation, luteal function was suppressed. These results extend previous observations of adverse effects of lead on ovarian activity and fertility in monkeys.     

Alkaline phosphatase phenotypes in tumour and non-tumour cell lines: not an invariable marker for neoplastic transformation

The cytochemical localisation and presumed isoenzyme type (based on selective inhibition experiments) of alkaline phosphatase in 5 cell lines derived frrom normal human, rat, mouse and hamster tissues, 6 human lymphoblastoid lines and 6 human and mouse tumour-derived cell lines are described. Enzyme activity varied between the cell lines. An isoenzyme inhibited by L-phenylalanine was present in 3 normal lines, 3 lymphoblastoid lines and 2 tumour lines. The presence of this isoenzyme cannot be used as a marker of neoplastic transformation.     

Mapping the polarity profiles of general anesthetic target sites using n-alkane-(alpha, omega)-diols

The effects of the homologous series of n-alkane-(alpha, omega)-diols have been studied on the inhibition of the purified firefly luciferase enzyme from Photinus pyralis, the inhibition of the purified bacterial luciferase enzyme from Vibrio harveyi, and the induction of general anesthesia in Xenopus laevis tadpoles. All but one of the diols tested were found to be reversible general anesthetics. The diols inhibited firefly luciferase by competing with its normal substrate firefly luciferin, and they inhibited bacterial luciferase by competing with the substrate n-decanal. For all but the smallest agent (1,4-butanediol), only a single diol molecule was found to be involved in the inhibition of the enzymes. Inhibition constants Ki were determined for the enzymes, and general anesthetic EC50 concentrations were determined for tadpoles. These data were then used in conjunction with previously determined n-alkane and n-alcohol data to calculate, as a function of chain length, the incremental standard Gibbs free energies delta (delta G0) for adding apolar -CH2- groups and for converting apolar terminal -CH3 groups to polar -CH2OH groups. The resulting plots of delta (delta G0) versus chain length gave a consistent mapping of the polarity profiles of the anesthetic-binding pockets. They clearly reveal the existence of two substantial and distinct polar regions in the anesthetic-binding pocket of firefly luciferase but only one such region for bacterial luciferase and for the unknown target sites underlying general anesthesia. The polarities and geometric properties of these different binding sites for straight-chain anesthetics are discussed in terms of simple models.     

Synchronization of the behaviour within nests of the antLeptothorax acervorum (Fabricius)—II. Modelling the phenomenon and predictions from the model

Observations on activity of ants of the speciesLeptothorax acervorum show that ants within the nest are inactive for about 72% of their time (Frankset al., 1990.Bull. math. Biol.,52, 597–612). By examination of the activity of individual ants it is demonstrated that activity bouts of individuals are highly synchronized. The bursts of activity detected by Frankset al. occurred three to four times per hour. In this paper we develop a model to describe the phenomenon. As a result of the interdependence of the number of active ants within the nest and the high level of community activity some predictions are made, which are supported by experimental data in a quantitative way. In case of starvation the number of active ants will increase and no rhythms should occur. When proportionally more brood is present the rhythms should occur with a higher frequency. Eventually the rhythm breaks down and a stable equilibrium is reached.     

A method of synchronization of normal and malignant human cells in culture.

A method is described for providing reproducible S phase parasynchrony in both normal mesenchyme and transformed epithelia. Cells were seeded at low density in medium containing 10% serum. 24 h later the serum concentration was reduced to 0.5%. After 110th the cells were collected at the G1/S boundary in fresh medium containing 10% serum plus 2.5mM hydroxyurea over 20h. After removal of hydroxyurea and trypsinization the re-plated cells entered the S phase with a high degree of synchrony, as judged by autoradiography, pulse-labelling with 3H-thymidine, cell growth and time lapse cinematography. By 6h after synchronization 80% of the population had entered the S phase and between 10-13h 70% went through mitosis.