Sexual colouration and sperm traits in guppies

The relationships among the area, hue, saturation and brightness of orange colouration and sperm traits in the guppy Poecilia reticulata were investigated. Males with greater areas of orange colouration had significantly larger sperm loads, more motile sperm and longer sperm relative to males with relatively little orange colouration. Males with greater areas of orange colouration did not possess more viable sperm than males with relatively little orange colouration. There was no evidence that any of the sperm traits were related to the hue, saturation or brightness of the orange colouration. These results are discussed in the context of the roles that direct and indirect selection might play in maintaining female preference for male guppies with large areas of orange colouration.     

Nicotine and its metabolites. Radioimmunoassay for gamma-(3-pyridyl)-gamma-oxo-N-methylbutyramide

A radioimmunoassay has been developed for the nicotine metabolite γ-(3-pyridyl)-γ-oxo-N-methylbutyramide. The sensitivity and specificity of the assay allow the determination of this compound at the picomole level in the presence of several structurally related molecules including nicotine and seven other nicotine metabolites. The assay has been used to characterize the enzyme system present in rabbit liver extract responsible for the conversion of cotinine to the oxoamide, and to measure oxoamide levels in urine, sera, and amniotic fluid of smokers. High-pressure liquid chromatography was used as an independent method to follow the enzymatic oxidation and in conjunction with the radioimmunoassay to analyze the urine samples.     

How air pollution influences clinical management of respiratory diseases. A case-crossover study in Milan

Background

Environmental pollution is a known risk factor for multiple diseases and furthermore increases rate of hospitalisations. We investigated the correlation between emergency room admissions (ERAs) of the general population for respiratory diseases and the environmental pollutant levels in Milan, a metropolis in northern Italy.

Methods

We collected data from 45770 ERAs for respiratory diseases. A time-stratified case-crossover design was used to investigate the association between air pollution levels and ERAs for acute respiratory conditions. The effects of air pollutants were investigated at lag 0 to lag 5, lag 0–2 and lag 3–5 in both single and multi-pollutant models, adjusted for daily weather variables.

Results

An increase in ozone (O₃) levels at lag 3–5 was associated with a 78% increase in the number of ERAs for asthma, especially during the warm season. Exposure to carbon monoxide (CO) proved to be a risk factor for pneumonia at lag 0–2 and in the warm season increased the risk of ERA by 66%. A significant association was found between ERAs for COPD exacerbation and levels of sulphur dioxide (SO₂), CO, nitrate dioxide (NO₂), and particulate matter (PM₁₀ and PM_2.5). The multipollutant model that includes all pollutants showed a significant association between CO (26%) and ERA for upper respiratory tract diseases at lag 0–2. For chronic obstructive pulmonary disease (COPD) exacerbations, only CO (OR 1.19) showed a significant association.

Conclusions

Exposure to environmental pollution, even at typical low levels, can increase the risk of ERA for acute respiratory diseases and exacerbation of obstructive lung diseases in the general population.     

EVOLUTION OF MATE CHOICE FOR GENOME-WIDE HETEROZYGOSITY

The extent to which indirect genetic benefits can drive the evolution of directional mating preferences for more ornamented mates, and the mechanisms that maintain such preferences without depleting genetic variance, remain key questions in evolutionary ecology. We used an individual-based genetic model to examine whether a directional preference for mates with higher genome-wide heterozygosity ( H ), and consequently greater ornamentation, could evolve and be maintained in the absence of direct fitness benefits of mate choice. We specifically considered finite populations of varying size and spatial genetic structure, in which parent–offspring resemblance in heterozygosity could provide an indirect benefit of mate choice. A directional preference for heterozygous mates evolved under broad conditions, even given a substantial direct cost of mate choice, low mutation rate, and stochastic variation in the link between individual heterozygosity and ornamentation. Furthermore, genetic variance was retained under directional sexual selection. Preference evolution was strongest in smaller populations, but weaker in populations with greater internal genetic structure in which restricted dispersal increased local inbreeding among offspring of neighboring females that all preferentially mated with the same male. These results suggest that directional preferences for heterozygous or outbred mates could evolve and be maintained in finite populations in the absence of direct fitness benefits, suggesting a novel resolution to the lek paradox.     

Temperature-dependent inactivation of nucleic acid binding and aggregation of the 1,25-dihydroxyvitamin D3 receptor

The interaction of the 1α,25-dihydroxyvitamin D₃ receptor with immobilized calf thymus DNA has been compared with its sedimentation properties on hypotonic sucrose gradients. Forty to sixty percent of total hormone:receptor complexes formed at 4 °C were retained by DNA-cellulose and could be eluted by 0.18 to 0.2 m KCl. In contrast, heating preparations to 25 °C rapidly and irreversibly converted receptor to a form which bound hormone and DEAE-cellulose normally, but was unable to associate with DNA. Similarly, the ability of receptor to aggregate to a 6 S species was labile at 25 °C. Stabilization of receptor in the DNA binding aggregating form was accomplished using Ca²⁺, Mg²⁺, Mn²⁺, or Na₂MoO₄ while several protease and phosphatase inhibitors were ineffective. An examination of DNA binding properties of aggregating and nonaggregating receptor forms revealed that only receptor competent to enter into aggregates could bind DNA suggesting that a functional nucleic acid binding site, and, hence, a nucleic acid interaction is necessary for aggregate formation. Consistent with this view, an RNA:receptor interaction appears to be involved in formation of the 6 S complex since removal of RNA by ribonuclease treatment or purification of receptor reduced aggregation, an effect that could be reversed by addition of purified RNA.     

Photosharing websites may improve Hemiptera biodiversity knowledge and conservation

Internet photosharing websites is a very recent and powerful tool for the study of biodiversity, and a meeting point of general public fond of nature and professional naturalists. The article discusses when an uploaded picture is scientifically valuable, and the benefits of structured hosting websites for the most fruitful information retrieval. Examples are given of faunistic, biological, ecological and conservation results concerning Hemiptera provided by information download from photosharing websites.     

Development of anabolic-androgenic steroids purity certified reference materials for anti-doping

Background

The need for certified reference materials (CRM) of anabolic-androgenic steroids reference materials was emphasized by the Beijing 2008 Olympic game as a tool to improve comparability, ensuring accuracy and traceability of analytical results for competing athletes. The China National Institute of Metrology (NIM) responded to the state request by providing seven anabolic-androgenic steroids (AAS) reference materials for Beijing Olympic anti-doping, GBW (E) 100086-GBW (E) 100092.

Experimental

This work describes the production of the series of AAS CRMs, according to ISO Guides 34 and 35 [1] and [2], which comprises the material processing, homogeneity and stability assessment, CRMs’ characterization including moisture content, trace metal content. The AASs’ purity values were assigned with collaborative study involved eight laboratories applying high resolution liquid chromatography-diode array detector (HPLC-DAD). Homogeneity of the AAS CRMs were determined by an in-house validated liquid chromatographic methodology. Potential degradation during storage was also investigated and a shelf-life based on this value was established.

Results

The certified values of CRMs were 99.76 ± 0.079%, 99.76 ± 0.25%, 99.63 ± 0.09%, 99.67 ± 0.11%, 98.82 ± 0.56%, 96.30 ± 0.39% and 99.71 ± 0.49% (purity ± expanded uncertainty with confidence level of 95%) for methyltestosterone, testosterone propionate, nandrolone, nandrolone 17-propionate, boldenone, trenbolone acetate and testosterone respectively.

Conclusions

The certified values for all the studied AAS reference materials are traceable to the international system of units (SI). The CRMs developed were applied by 32 laboratory including sports organizations and analytical laboratories during the 2008 Olympic game for anti-doping control.     

Characteristics of the induction of aldehyde dehydrogenase in rat liver

The activity of rat liver supernatant aldehyde dehydrogenase is increased by phenobarbital treatment in one selected strain (RR) but not in another strain (rr) of animals derived from randomally bred populations (Deitrich, Collins, and Erwin (1972) J. Biol. Chem., 247, 7232). Before 14 days of age, increased enzyme activity after phenobarbital treatment is minimal but between 30 and 60 days of age there is a maximal increase in activity after phenobarbital treatment. Using animals of this age, it was shown that both cycloheximide and actinomycin D block this response to phenobarbital. Phenobarbital treatment decreases heat stability of crude preparations of the enzyme from RR rats, but increases heat stability of the enzyme from rr animals.     

Nature De-naturalised: Modes of Relation with the Environment among the Drung of Northwest Yunnan (China)

ABSTRACT

This article is about the ways the Drung (Dulong), a minority inhabiting a remote mountainous valley of Northwest Yunnan province (China), view the ‘natural world’ as part of a cosmological order in which human society is integrated. The article explores the principles of differentiation that preside over the modes of relation between the diverse components of this world, by paying close attention to subsistence activities. Until recently, the Drung people practised swidden agriculture, and hunting and collecting remained important secondary sources of food. These activities imply specific relationships with natural forces, deities and spirits, which constitute a socio-cultural means of accessing natural resources and obtaining prosperity, or ‘good fortune’. Four mutually non-exclusive modalities of transaction with these entities are identified, which capture the variability of peoples’ attitudes toward natural resources and ideas of social reproduction. Recent socio-economic reforms that have brought traditional cultivation to an end, threatening Drung people’s livelihood and culture, seem to influence the dominance of a certain modality of economic transaction.