Phenology of scramble polygyny in a wild population of chrysolemid beetles: the opportunity for and the strength of sexual selection

Recent debate has highlighted the importance of estimating both the strength of sexual selection on phenotypic traits, and the opportunity for sexual selection. We describe seasonal fluctuations in mating dynamics of Leptinotarsa undecimlineata (Coleoptera: Chrysomelidae). We compared several estimates of the opportunity for, and the strength of, sexual selection and male precopulatory competition over the reproductive season. First, using a null model, we suggest that the ratio between observed values of the opportunity for sexual selections and their expected value under random mating results in unbiased estimates of the actual nonrandom mating behavior of the population. Second, we found that estimates for the whole reproductive season often misrepresent the actual value at any given time period. Third, mating differentials on male size and mobility, frequency of male fighting and three estimates of the opportunity for sexual selection provide contrasting but complementary information. More intense sexual selection associated to male mobility, but not to male size, was observed in periods with high opportunity for sexual selection and high frequency of male fights. Fourth, based on parameters of spatial and temporal aggregation of female receptivity, we describe the mating system of L. undecimlineata as a scramble mating polygyny in which the opportunity for sexual selection varies widely throughout the season, but the strength of sexual selection on male size remains fairly weak, while male mobility inversely covaries with mating success. We suggest that different estimates for the opportunity for, and intensity of, sexual selection should be applied in order to discriminate how different behavioral and demographic factors shape the reproductive dynamic of populations.     

S-allylmercaptocysteine scavenges hydroxyl radical and singlet oxygen <Emphasis Type="Italic">in vitro</Emphasis> and attenuates gentamicin-induced oxidative and nitrosative stress and renal damage <Emphasis Type="Italic">in vivo</Emphasis>

Background  

Oxidative and nitrosative stress have been involved in gentamicin-induced nephrotoxicity. The purpose of this work was to study the effect of S-allylmercaptocysteine, a garlic derived compound, on gentamicin-induced oxidative and nitrosative stress and nephrotoxicity. In addition, the in vitro reactive oxygen species scavenging properties of S-allylmercaptocysteine were studied.     

Respiratory Mechanics and Plasma Levels of Tumor Necrosis Factor Alpha and Interleukin 6 Are Affected by Gas Humidification during Mechanical Ventilation in Dogs

The use of dry gases during mechanical ventilation has been associated with the risk of serious airway complications. The goal of the present study was to quantify the plasma levels of TNF-alpha and IL-6 and to determine the radiological, hemodynamic, gasometric, and microscopic changes in lung mechanics in dogs subjected to short-term mechanical ventilation with and without humidification of the inhaled gas. The experiment was conducted for 24 hours in 10 dogs divided into two groups: Group I (n = 5), mechanical ventilation with dry oxygen dispensation, and Group II (n = 5), mechanical ventilation with oxygen dispensation using a moisture chamber. Variance analysis was used. No changes in physiological, hemodynamic, or gasometric, and radiographic constants were observed. Plasma TNF-alpha levels increased in group I, reaching a maximum 24 hours after mechanical ventilation was initiated (ANOVA p = 0.77). This increase was correlated to changes in mechanical ventilation. Plasma IL-6 levels decreased at 12 hours and increased again towards the end of the study (ANOVA p>0.05). Both groups exhibited a decrease in lung compliance and functional residual capacity values, but this was more pronounced in group I. Pplat increased in group I (ANOVA p = 0.02). Inhalation of dry gas caused histological lesions in the entire respiratory tract, including pulmonary parenchyma, to a greater extent than humidified gas. Humidification of inspired gases can attenuate damage associated with mechanical ventilation.     

Serum Lipid Levels and Dyslipidaemia Prevalence among 2–10 Year-Old Northern Mexican Children

Background and Aims

The increase in overweight and obese children may be linked to increased rates of dyslipidaemia. The aim was to assess the prevalence of dyslipidaemia and associated risk factors among the Northern Mexican child population.

Methods and Results

Four hundred and fifty-one subjects aged between 2 and 10 (47.5% girls) took part in the Nuevo León State Survey of Nutrition and Health 2011–2012. According to the 2011 Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents, serum lipid levels (mg/dL) were categorized into three subgroups (acceptable, borderline-high/low or high/low) as follows: TChol: acceptable <170, borderline-high 170–199, high ≥200; LDL-chol: acceptable <110, borderline-high 110–129, high ≥130; non-HDL-chol: acceptable <120, borderline-high 120–144, high ≥145; HDL-chol: acceptable >45, borderline-low 40–45, low <40; and TG: acceptable <75, borderline-high 75–99, high ≥100 in ≤9 year-old children, and acceptable <90, borderline-high 90–129, and high ≥130 in 10 year-old children. The overall prevalence of borderline-high + high TG, non-HDL-chol, TChol, and LDL-chol was 63.0%, 44.1%, 43.5%, and 29.9%, respectively. The overall prevalence of borderline-low + low HDL-chol was 46.3%. The overall frequency of dyslipidaemia was 54.3%. Thirteen children (2.9%) had all five symptoms of dyslipidaemia. The most common dyslipidaemia was high TG in combination (26.2%) and in isolation (10.6%).

Conclusions

Half of the children had at least one abnormal lipid concentration. A high TG level was the most frequent dyslipidaemia. Obesity was associated with the occurrence of at least one abnormal lipid level. These findings emphasize the need to pay further attention to the prevention of cardiovascular disease and obesity from an early age.     

Surface Plasmon Resonances of Metallic Nanostars/Nanoflowers for Surface-Enhanced Raman Scattering

We investigate theoretically the optical properties associated to plasmon resonances of metal nanowires with cross section given by low-order Chebyshev nanoparticles (like rounded-tip nanostars or nanoflowers). The impact of the nanoflower shape is analyzed for varying symmetry and deformation parameter through the spectral dependence of resonances and their corresponding near field distributions. Large field intensity enhancements are obtained at the gaps between petals, apart from the tips themselves, which make these nanostars/nanoflowers specially suitable to host molecules for surface-enhanced Raman scattering sensing applications.     

Nascent polypeptide sequences that influence ribosome function

Ribosomes catalyze protein synthesis using transfer RNAs and auxiliary proteins. Historically, ribosomes have been considered nonspecific translational machines, having no regulatory functions. However, a new class of regulatory mechanisms has been discovered that is based on interactions occurring within the ribosomal peptide exit tunnel that result in ribosome stalling during translation of an appropriate mRNA segment. These discoveries reveal an unexpectedly dynamic role ribosomes play in regulating their own activity. By using nascent leader peptides in combination with bound specific amino acids or antibiotics, ribosome functions can be altered significantly resulting in regulated expression of downstream coding regions. This review summarizes relevant findings in recent articles and outlines our current understanding of nascent peptide-induced ribosome stalling in regulating gene expression.     

Parsimony Analysis of Endemicity (PAE) of Mexican hydrological basins based on helminth parasites of freshwater fishes

Aim The distributional patterns of helminthological fauna of freshwater fishes were analysed to postulate a general hypothesis on the relationships of some Mexican hydrological systems. Location Eight hydrological systems of central and eastern Mexico were studied and compared with records from Nicaragua. Methods A Parsimony Analysis of Endemicity (PAE) was applied to the presence/absence of ninety‐two helminth parasite taxa (Monogeneans, Digeneans, Cestodes, Acanthocephalans and Nematodes) of freshwater fishes, from eight Mexican hydrological systems, using the Hennig86 program. Results The results represent the first attempt for a biogeographical analysis through application of the PAE method to the distributional patterns of helminth parasites of freshwater fishes in Mexico. A single most parsimonious cladogram was obtained, which grouped all the Neotropical systems in accordance with previous proposals based on other plant and animal taxa. Main conclusions The most basal systems were Santiago and Lerma basins, which exhibited Nearctic affinities. The remaining areas of the cladogram showed Neotropical affinities. All the southeastern systems were grouped in a clade with the Nicaragua system, providing support for a ‘Mesoamerican province’ based on helminth parasites of cichlids. The cladogram also suggests that the treatment of the Lerma‐Santiago basin as a single biogeographical unit is inaccurate and that they should be treated as separate systems.     

Mutant p53 Aggregates into Prion-like Amyloid Oligomers and Fibrils: IMPLICATIONS FOR CANCER

Over 50% of all human cancers lose p53 function. To evaluate the role of aggregation in cancer, we asked whether wild-type (WT) p53 and the hot-spot mutant R248Q could aggregate as amyloids under physiological conditions and whether the mutant could seed aggregation of the wild-type form. The central domains (p53C) of both constructs aggregated into a mixture of oligomers and fibrils. R248Q had a greater tendency to aggregate than WT p53. Full-length p53 aggregated into amyloid-like species that bound thioflavin T. The amyloid nature of the aggregates was demonstrated using x-ray diffraction, electron microscopy, FTIR, dynamic light scattering, cell viabilility assay, and anti-amyloid immunoassay. The x-ray diffraction pattern of the fibrillar aggregates was consistent with the typical conformation of cross β-sheet amyloid fibers with reflexions of 4.7 Å and 10 Å. A seed of R248Q p53C amyloid oligomers and fibrils accelerated the aggregation of WT p53C, a behavior typical of a prion. The R248Q mutant co-localized with amyloid-like species in a breast cancer sample, which further supported its prion-like effect. A tumor cell line containing mutant p53 also revealed massive aggregation of p53 in the nucleus. We conclude that aggregation of p53 into a mixture of oligomers and fibrils sequestrates the native protein into an inactive conformation that is typical of a prionoid. This prion-like behavior of oncogenic p53 mutants provides an explanation for the negative dominance effect and may serve as a potential target for cancer therapy.