Social status and availability of females determine patterns of sperm allocation in the fowl

Where sperm competition occurs, the number and quality of sperm males inseminate relative to rival males influences fertilization success. The number of sperm males produce, however, is limited, and theoretically males should allocate sperm according to the probability of gaining future reproductive opportunities and the reproductive benefits associated with copulations. However, the reproductive opportunities and value of copulations males obtain can change over their lifetime, but whether individuals respond to such changes by adjusting the way they allocate sperm is unclear. Here we show that, in the fowl, Gallus gallus, dominant males, which have preferential access to females, modulate the number of sperm they ejaculate according to the availability of females. When presented with two females, dominant males allocated more sperm to higher quality females, whereas when females were on their own, only copulation order had an affect on their sperm numbers. In contrast, subordinate males, whose mating activity is restricted by dominant males, allocated high numbers of sperm to initial copulations, irrespective of female availability. We further show, by manipulating male social status, that sperm allocation is both phenotypically plastic, with males adjusting their patterns of sperm allocation according to their dominance rank, and intrinsic, with males being consistently different in the way they allocate sperm, once the effects of social status are taken into account. This study suggests that males have evolved sophisticated patterns of sperm allocation to respond to frequent fluctuations in the value and frequency of reproductive opportunities.     

Alcohol consumption and the risk of incident atrial fibrillation among people with cardiovascular disease

Background:

Moderate alcohol consumption may reduce cardiovascular events, but little is known about its effect on atrial fibrillation in people at high risk of such events. We examined the association between moderate alcohol consumption and the risk of incident atrial fibrillation among older adults with existing cardiovascular disease or diabetes.

Methods:

We analyzed data for 30 433 adults who participated in 2 large antihypertensive drug treatment trials and who had no atrial fibrillation at baseline. The patients were 55 years or older and had a history of cardiovascular disease or diabetes with end-organ damage. We classified levels of alcohol consumption according to median cut-off values for low, moderate and high intake based on guidelines used in various countries, and we defined binge drinking as more than 5 drinks a day. The primary outcome measure was incident atrial fibrillation.

Results:

A total of 2093 patients had incident atrial fibrillation. The age- and sex-standardized incidence rate per 1000 person-years was 14.5 among those with a low level of alcohol consumption, 17.3 among those with a moderate level and 20.8 among those with a high level. Compared with participants who had a low level of consumption, those with higher levels had an increased risk of incident atrial fibrillation (adjusted hazard ratio [HR] 1.14, 95% confidence interval [CI] 1.04–1.26, for moderate consumption; 1.32, 95% CI 0.97–1.80, for high consumption). Results were similar after we excluded binge drinkers. Among those with moderate alcohol consumption, binge drinkers had an increased risk of atrial fibrillation compared with non–binge drinkers (adjusted HR 1.29, 95% CI 1.02–1.62).

Interpretation:

Moderate to high alcohol intake was associated with an increased incidence of atrial fibrillation among people aged 55 or older with cardiovascular disease or diabetes. Among moderate drinkers, the effect of binge drinking on the risk of atrial fibrillation was similar to that of habitual heavy drinking.A trial fibrillation is associated with an increased risk of stroke and a related high burden of mortality and morbidity, both in the general public and among patients with existing cardiovascular disease.^1,2 The prevalence of atrial fibrillation increases steadily with age, as do the associated risks, and atrial fibrillation accounts for up to 23.5% of all strokes among elderly people.³Moderate alcohol consumption has been reported to be associated with a reduced risk of cardiovascular disease and all-cause death,^1,2 whereas heavy alcohol intake and binge drinking have been associated with an increased risk of stroke,⁴ cardiovascular disease and all-cause death.^5,6 Similarly, heavy drinking and binge drinking are associated with an increased risk of incident atrial fibrillation in the general population.⁷ However, the association between moderate drinking and incident atrial fibrillation is less consistent and not well understood among older people with existing cardiovascular disease.In this analysis, we examined whether drinking moderate quantities of alcohol, and binge drinking, would be associated with an increased risk of incident atrial fibrillation in a large cohort of people with existing cardiovascular disease or diabetes with end-organ damage who had been followed prospectively in 2 long-term antihypertensive drug treatment trials.     

Genome shrinkage and loss of nutrient-providing potential in the obligate symbiont of the primitive termite Mastotermes darwiniensis

Beneficial microbial associations with insects are common and are classified as either one or a few intracellular species that are vertically transmitted and reside intracellularly within specialized organs or as microbial assemblages in the gut. Cockroaches and termites maintain at least one if not both beneficial associations. Blattabacterium is a flavobacterial endosymbiont of nearly all cockroaches and the termite Mastotermes darwiniensis and can use nitrogenous wastes in essential amino acid and vitamin biosynthesis. Key changes during the evolutionary divergence of termites from cockroaches are loss of Blattabacterium, diet shift to wood, acquisition of a specialized hindgut microbiota, and establishment of advanced social behavior. Termite gut microbes collaborate to fix nitrogen, degrade lignocellulose, and produce nutrients, and the absence of Blattabacterium in nearly all termites suggests that its nutrient-provisioning role has been replaced by gut microbes. M. darwiniensis is a basal, extant termite that solely retains Blattabacterium, which would show evidence of relaxed selection if it is being supplanted by the gut microbiome. This termite-associated Blattabacterium genome is ～8% smaller than cockroach-associated Blattabacterium genomes and lacks genes underlying vitamin and essential amino acid biosynthesis. Furthermore, the M. darwiniensis gut microbiome membership is more consistent between individuals and includes specialized termite gut-associated bacteria, unlike the more variable membership of cockroach gut microbiomes. The M. darwiniensis Blattabacterium genome may reflect relaxed selection for some of its encoded functions, and the loss of this endosymbiont in all remaining termite genera may result from its replacement by a functionally complementary gut microbiota.     

Cyclic tetrapyrrolic photosensitizers from Cladophora patentiramea (Cladophoraceae, Chlorophyta) and Turbinaria conoides (Sargassaceae, Phaeophyta) for photodynamic therapy

In screening for novel photosensitizers for photodynamic therapy, 14 seaweed samples from Port Dickson in Malaysia were collected. Methanolic extracts of these samples were prepared and evaluated for phototoxicity using a short-term cell viability assay, where promyelocytic leukemia cells, HL60 were incubated with the extracts prior to irradiation with a broad spectrum light at 9.6?J?cm^?2 (equivalent to 10.5?mW?cm^?2 for 10?min). Four of the methanolic extracts demonstrated moderate to strong phototoxicity and bioassay-guided isolation of photosensitizers was carried out on two selected seaweeds to yield a total of eight cyclic tetrapyrrolic compounds which are derivatives of chlorophyll-a and -b. Seven of these compounds showed >50% phototoxicity at 5?μg?mL^?1 while exhibiting minimal cytotoxicity in the dark, which is an important characteristic of an ideal photosensitizer.     

The interactive effect of alcohol and folic acid on genome stability in human WIL2-NS cells measured using the cytokinesis-block micronucleus cytome assay

Chromosomal mutations are commonly found in cancer cells, and can be caused by several factors including dietary insufficiency and exposure to environmental and life-style genotoxins. Folate (vitamin B9), one of the essential micronutrients, is required for DNA repair and synthesis and to maintain genome stability. Since excessive alcohol (ethanol) consumption may alter folate status and low folate might alter susceptibility to alcohol toxicity, a study was performed to investigate the individual and interactive impacts of folic acid (FA) and ethanol on genome stability in vitro. The experiments were performed using WIL2-NS cells cross-tested at three FA (20, 200 and 2000 nM) and four ethanol concentrations (0, 0.09, 0.36 and 1.34%, v/v) over a two-week culture time. Chromosomal damage and cytotoxicity were measured using the cytokinesis-block micronucleus cytome assay. The present study showed dose-related genotoxic effects of both decreasing folic acid concentration and increased ethanol on day 15 resulting in significant induction of micronuclei, nuclear buds and nucleoplasmic bridges which are biomarkers of chromosome breakage or loss, gene amplification and chromosomal rearrangement, respectively. Increased ethanol and FA deficiency interacted to further significantly increase micronuclei and nucleoplasmic bridges. However there was no evidence showing alcohol's ability to cleave FA. The findings from this study suggest a protective effect of FA against alcohol-induced DNA damage and that FA deficiency in the physiological range has a stronger impact on genome stability than exposure to cytotoxic doses of ethanol achievable in binge drinking.     

Real-time determination of kinetics of adsorption of lead(II) onto palm shell-based activated carbon using ion selective electrode

In this study, the kinetics of adsorption of Pb(II) from aqueous solution onto palm shell-based activated carbon (PSAC) were investigated by employing ion selective electrode (ISE) for real-time Pb(II) and pH monitoring. Usage of ISE was very appropriate for real-time adsorption kinetics data collection as it facilitated recording of adsorption data at very specific and short time intervals as well as provided consistent kinetics data. Parameters studied were initial Pb(II) concentration and agitation speed. It was found that increases in initial Pb(II) concentration and agitation speed resulted in higher initial rate of adsorption. Pseudo first-order, pseudo second-order, Elovich, intraparticle diffusion and liquid film diffusion models were used to fit the adsorption kinetics data. It was suggested that chemisorption was the rate-controlling step for adsorption of Pb(II) onto PSAC since the adsorption kinetics data fitted both the pseudo second-order and Elovich models well.     

Shark and ray teeth from the Hauterivian (Lower Cretaceous) of north-east England

Sampling of hiatal horizons within the Hauterivian part of the Speeton Clay Formation of north-east England has produced teeth of several species of sharks and rays, four of which are previously unnamed. One species of shark, Cretorectolobus doylei sp. nov., and two species of rays, Spathobatis rugosus sp. nov. and Dasyatis speetonensis sp. nov., are named, whilst the presence of an indeterminate triakid shark is also noted. Synechodus dubrisiensis (Mackie) is shown to be a senior synonym of S. michaeli Thies. Although the dasyatid ray and triakid shark are by far the oldest representatives of their respective families, the overall composition of the fauna is considered to resemble more closely assemblages known from the Jurassic than those from upper parts of the Cretaceous.