High serum S-equol content in red clover fed ewes: the classical endocrine disruptor is a single enantiomer

An expedient high performance liquid chromatography (HPLC) method was developed for the quantitative analysis of environmental estrogenic isoflavonoids, particularly (S)-equol, in red clover fed ewes. We report here the phytoestrogen analysis of red clover silage and the serum of ewes fed with this feed. Ewes received daily 10.5 g of formononetin on average from red clover silage. In the serum samples a major part of formononetin had been metabolised to equol (average 7.7 μg ml⁻¹). According to chiral HPLC analysis, the equol present in the serum of ewes was solely of the (S)-form. We also demonstrate the presence of the metabolite O-demethylangolensin (O-DMA) in ovine serum.     

Delayed maturation in plumage colour: Evidence for the female-mimicry hypothesis in the kestrel

Summary In many sexually dichromatic species, young males have female-like plumage during their first potential breeding year. The female-mimicry hypothesis (FMH) supposes that by possessing female-like plumage young males deceive older conspicuous males into believing that they are females, thus reducing competition from adult males. The status-signalling hypothesis (SSH) supposes that adult males can distinguish sex, but postulates that young males reduce competition from adult males by reliably signaling low status with their dull plumage. We tested these hypotheses in the European kestrel (Falco tinnunculus). Female-like young males settled to breed closer to adult males than did other adult males (Figs. 1a, b). By settling near adult males, young males seemed to increase their chance of mating with adult females. Adult female-young male pairs had better reproductive success than yearling-yearling pairs. These results suggest that there is an adaptive value in possessing a female-like plumage colour in the breeding season. To test the FMH, we measured sexual preference of adult males when adult females and young males were simultaneously shown in an aviary. Adult males were unable to recognize sex, because in half the cases they preferred young males (Fig. 3). However, when adult males and females were shown simultaneously, males preferred females (Fig. 2). Our results support the FMH rather than the SSH, because young males successfully deceived older males by their plumage.     

Lysozyme,chitinase and exo-N-acetyl-β-D-glucosaminidase (NAGase) in lymphomyeloid tissue of marine fishes

Lymphomyeloid (haemopoietic) tissues produce or store blood cells — among these leucocytes rich in lysosomal enzymes. The thymus, unlike the other lymphomyeloid tissues found in fish, produces exclusively lymphocytes. The carbohydrate-hydrolysing enzymes lysozyme (EC 3.2.1.17), chitinase (EC 3.2.1.14) and exo-N-acetyl--D-glucosaminidase (NAGase; EC 3.2.1.30) were assayed in various lymphomyeloid tissues of the cartilaginous fish Chimaera monstrosa, Squalus acanthias, Etmopterus spinax and Raja radiata, and in the thymus of the marine teleost Lophius piscatorius. Lysozyme activity was high in the cranial lymphomyeloid tissue of C. monstrosa; in Leydig's organ (oesophageal lymphomyeloid tissue) and the spleen from E. spinax; and in Leydig's organ, the epigonal organ and the spleen from R. radiata. Little or no lysozyme activity was found in Leydig's organ and the epigonal organ of S. acanthias, or in the thymus of C. monstrosa, R. radiata and L. piscatorius. The pH optima for lysozyme activities lay between 4.8 and 5.4 when assayed photometrically. Chitinase was most active at pH 1 in Leydig's organ from R. radiata, and at pH 2.7 in the epigonal organ from S. acanthias. The chitinolytic activity in Leydig's organ of E. spinax may be due to lysozyme. The optimum for NAGase activity in Leydig's organ from R. radiata lay at pH 4.0, that from S. acanthias and E. spinax at pH 4.5. The role of the enzymes in the defense against microorganisms and parasites is discussed.     

Tests for a biased sex ratio when the data are clustered

In behavioral ecology the overall sex ratio in a population of birds is often tested to see if it differs from a 50/50 ratio. In recent publications the binomial test or the ² test are carried out although the sexes of chicks within the same nest may not be independent. The lack of independence occurs since female birds can adjust the sex ratio in an adaptive way as demonstrated in recent studies. In order to take dependence into consideration the Wilcoxon signed rank test based on the within-brood differences between the proportions of sons and daughters was performed in a study investigating great tit hatchling sex ratios. We compare this test with a test based on an optimally weighted estimator recently proposed for medical studies with clustered binary data. According to our simulation results, this novel test is more powerful than the Wilcoxon signed rank test and should be used for the analysis of avian sex ratios. The methods are illustrated with real data from the great reed warbler.     

Rate of growth and longevity of a large colony of Pentapora foliacea (Bryozoa) recorded in their oxygen isotope profiles

We studied the growth patterns and the stable oxygen isotopic composition of an individual of Pentapora foliacea (Ellis and Solander 1786) collected on October 6, 1978 from the Bristol Channel, Pembrokeshire, UK, Irish Sea. The stable oxygen isotopes are in equilibrium with the ambient seawater and show a marked seasonal variation reflecting seasonal water temperature changes. The stable oxygen isotopes further suggest that regular growth patterns of less calcified growth bands, which are secreted in winter, are perennial. These winter growth check lines can easily be used to determine longevity of these bryozoa colonies and of annual growth rates. The colony analysed is at least 3-years-old with an annual growth rate of approximately 2 cm per year.     

Metabolic disposition of lactate in the horseshoe crab Limulus polyphemus and the stone crab Menippe mercenaria

The metabolism of ¹⁴C-labelled lactate was investigated in the horseshoe crab Limulus polyphemus and the stone crab Menippe mercenaria. When a bolus of (¹⁴C-U)-D-lactate was injected into L. polyphemus, there was substantial release pf ¹⁴CO₂ into the medium. In the case of M. mercenaria, ¹⁴CO₂ release was also observed after injection of (¹⁴C-U)-L-lactate into experimental individuals. Analysis of the distribution of radioactivity in whole body extracts of both species revealed easily detectable amounts of radioactivity in the glycogen fraction, although the bulk of the radioactivity was in the cation, anion/neutral and CO₂ fractions. To investigate the metabolism of lactate further, ¹⁴C-labelled lactate was injected into large individuals of L. polyphemus and M. mercenaria, and the distribution of radioactivity was determined in the hemolymph, muscle and hepatopancreas. Utilization of (¹⁴C-U)-D-lactate by L. polyphemus resulted in the accumulation of significant amounts of labelled glucose in all three body compartments as well as the production of labelled glycogen in the telson levator muscle and hepatopancreas. Utilization of (¹⁴C-U)-L-lactate resulted in a similar pattern of glucose and glycogen labelling in the hemolymph, cheliped muscle and hepatopancreas of M. mercenaria. These studies demonstrate that both L. polyphemus and M. mercenaria have the capacity for glyco- and gluconeogenesis using lactate as the substrate.     

Female benefit,male risk: Polyandry in the true armyworm Pseudaletia unipuncta

In Lepidoptera polyandry is common and females may increase their lifetime reproductive output through repeated matings if they acquire essential resources from male ejaculates. However, the paternity of males mating with previously-mated females is far from assured unless sperm precedence is absolute. In this study on the polyandrous armyworm, Pseudaletia unipuncta, we used two strains of male (the black-eyed wild type and a red-eyed homozygous, recessive mutant), mated with red-eyed females, to determine (i) whether male investment has any impact on female reproductive output, and (ii) if females do benefit from multiple matings, to what extent males fertilize the eggs to which they contributed. Multiple mating resulted in a significant increase in both the fecundity and longevity of females. However, the degree of sperm precedence (those eggs fertilized by the second male) varied from 0–100%, but was not affected by either male size or age, or by the duration of copulation. In cases where sperm precedence was <50% (x = 12%) females produced significantly more eggs (1384 versus 940) prior to the second mating than females where sperm precedence was >50% (x = 89%), indicating that the quality of the first mating influenced the fertilization success of the female's second mate.