Larger testes are associated with a higher level of polyandry, but a smaller ejaculate volume, across bushcricket species (Tettigoniidae)

While early models of ejaculate allocation predicted that both relative testes and ejaculate size should increase with sperm competition intensity across species, recent models predict that ejaculate size may actually decrease as testes size and sperm competition intensity increase, owing to the confounding effect of potential male mating rate. A recent study demonstrated that ejaculate volume decreased in relation to increased polyandry across bushcricket species, but testes mass was not measured. Here, we recorded testis mass for 21 bushcricket species, while ejaculate (ampulla) mass, nuptial gift mass, sperm number and polyandry data were largely obtained from the literature. Using phylogenetic-comparative analyses, we found that testis mass increased with the degree of polyandry, but decreased with increasing ejaculate mass. We found no significant relationship between testis mass and either sperm number or nuptial gift mass. While these results are consistent with recent models of ejaculate allocation, they could alternatively be driven by substances in the ejaculate that affect the degree of polyandry and/or by a trade-off between resources spent on testes mass versus non-sperm components of the ejaculate.     

Increased copulation duration before ejaculate transfer is associated with larger spermatophores, and male genital titillators, across bushcricket taxa

Copulation duration varies considerably across species, but few comparative studies have examined factors that might underlie such variation. We examined the relationship between copulation duration (prior to spermatophore transfer), the complexity of titillators (sclerotized male genital contact structures), spermatophore mass and male body mass across 54 species of bushcricket. Using phylogenetic comparative analyses, we found that copulation duration was much longer in species with titillators than those without, but it was not longer in species with complex compared with simple titillators. A positive relationship was found between spermatophore size and copulation duration prior to ejaculate transfer, which supports the hypothesis that this represents a period of mate assessment. The slope of this relationship was steeper in species with simple rather than complex titillators. Although the data suggest that the presence of titillators is necessary to maintain long copulation prior to ejaculate transfer, mechanisms underlying this association remain unclear.     

Equipped to cope with climate change: traits associated with range filling across European taxa

In order to understand the ecological effects of climate change it is essential to forecast suitable areas for species in the future. However, species’ ability to reach potentially suitable areas is also critical for species survival. These ‘range‐shift’ abilities can be studied using life‐history traits related to four range‐shift stages: emigration, movement, establishment, and proliferation. Here, we use the extent to which species’ ranges fill the climatically suitable area available (‘range filling’) as a proxy for the ability of European mammals and birds to shift their ranges under climate change. We detect which traits associate most closely with range filling. Drawing comparisons with a recent analysis for plants, we ask whether the latitudinal position of species’ ranges supports the assertion that post‐glacial range‐shift limitations cause disequilibrium between ranges and climate. We also disentangle which of the three taxonomic groups has greatest range filling. For mammals, generalists and early‐reproducing species have the greatest range filling. For birds, generalist species with high annual fecundity, which live longer than expected based on body size, have the greatest range filling. Although we consider traits related to the four range‐shift stages, only traits related to establishment and proliferation ability significantly influence range filling of mammals and birds. Species with the greatest range filling are those whose range centroid falls in the latitudinal centre of Europe, suggesting that post‐glacial range expansion is a leading cause of disequilibrium with climate, although other explanations are also possible. Range filling of plants is lower than that of mammals or birds, suggesting that plants are more range‐limited by non‐climatic factors. Therefore, plants might be face greater non‐climatic restraints on range shifts than mammals or birds.     

Marriage and fatherhood are associated with lower testosterone in males

In order to study the hormonal correlates of the tradeoff between mating and parenting effort in human males, we examined the salivary testosterone (T) levels of 58 Boston-area men who were either unmarried (n=29), married without children (n=14), or married with children (n=15). Additionally, we asked participants to complete a questionnaire that surveyed their demographic, marital, and parenting backgrounds. We tested the hypotheses that (1) T levels will be lower in married than in unmarried men and (2) married men with children will have lower T levels than unmarried men and married men without children. We also tested a series of hypotheses relating variation in parenting and spousal relationships to T. We found that married men with and without children had significantly lower evening T than unmarried men. No significant differences in T were found among the groups in morning samples. Among married men without children, higher scores on a “spousal investment” measure and more hours spent with a man's wife on his last day off work were both associated with lower T levels. We suggest that lower T levels during the day among fathers may facilitate paternal care in humans by decreasing the likelihood that a father will engage in competitive and/or mating behavior.     

The influence of maternal effects on indirect benefits associated with polyandry

Despite numerous and diverse theoretical models for the indirect benefits of polyandry, empirical support is mixed. One reason for the difficulty in detecting indirect benefits of polyandry may be that these are subtle and are mediated by environmental effects, such as maternal effects. Maternal effects may be especially important if females allocate resources to their offspring depending on the characteristics of their mating partners. We test this hypothesis in the burying beetle Nicrophorus vespilloides, a species that provides extensive and direct parental care to offspring. We used a fully factorial design and mated females to one, two, three, four or five different males and manipulated conditions so that their offspring received reduced (12 h) or full (ca 72 h) maternal care. We found that average offspring fitness increased with full maternal care but there was no significant effect of polyandry or the interaction between the duration of maternal care and the level of polyandry on offspring fitness. Thus, although polyandry could provide a mechanism for biasing paternity towards high quality or compatible males, and variation in parental care matters, we found no evidence that female N. vespilloides gain indirect benefits by using parental care to bias the allocation of resources under different mating conditions.     

Characteristics of associated microflora of ejaculate from males with gonococcal infections

Species composition and biological properties of aerobic and anaerobic microflora from an ejaculate from males with acute and chronic gonococcal infection and from healthy men were studied. Patients with gonococcal infection were shown to present quantitative and qualitative changes in microbiocenosis of the reproductive tract. Patients with acute gonorrhea displayed decreased species diversity in contrast to healthy persons, while different species of associated with gonococci microbes with high persistent potential, were cultured in patients suffering from a chronic form of infection. The role of revealed pathological biocenosis patterns in developing chronic infection as well as postgonorrheal gonococci-free urethritis is discussed.     

Bacterial taxa associated with the lung lichen Lobaria pulmonaria are differentially shaped by geography and habitat

The correlation between the taxonomic composition of Alphaproteobacteria, Burkholderia and nitrogen fixers associated with the lichen Lobaria pulmonaria and the geographical distribution of the host was studied across four sites in Europe. Results proved that the diversity of Alphaproteobacteria is affected by geography, while those of Burkholderia and nitrogen fixers were mostly driven by local habitat. This difference indicates a higher stability of the association between Alphaproteobacteria and the lichen host.     

Substrate specificity of a maize ribosome-inactivating protein differs across diverse taxa.

The superfamily of ribosome-inactivating proteins (RIPs) consists of toxins that catalytically inactivate ribosomes at a universally conserved region of the large ribosomal RNA. RIPs carry out a single N-glycosidation event that alters the binding site of the translational elongational factor eEF1A and causes a cessation of protein synthesis that leads to subsequent cell death. Maize RIP1 is a kernel-specific RIP with the unusual property of being produced as a zymogen, proRIP1. ProRIP1 accumulates during seed development and becomes active during germination when cellular proteases remove acidic residues from a central domain and both termini. These deletions also result in RIP activation in vitro. However, the effectiveness of RIP1 activity against target ribosomes remains species-dependent. To determine the potential efficiency of maize RIP1 as a plant defense protein, we used quantitative RNA gel blots to detect products of RIP activity against intact ribosomal substrates from various species. We determined the enzyme specificity of recombinant maize proRIP1 (rproRIP1), papain-activated rproRIP1 and MOD1 (an active deletion mutant of rproRIP1) against ribosomal substrates with differing levels of RIP sensitivity. The rproRIP1 had no detectable enzymatic activity against ribosomes from any of the species assayed. The papain-activated rproRIP1 was more active than MOD1 against ribosomes from either rabbit or the corn pathogen, Aspergillus flavus, but the difference was much more marked when rabbit ribosomes were used as a substrate. The papain-activated rproRIP1 was much more active against rabbit ribosomes than homologous Zea mays ribosomes and had no detectable effect on Escherichia coli ribosomes.     

Variants associated with common disease are not unusually differentiated in frequency across populations

Genetic variants that contribute to risk of common disease may differ in frequency across populations more than random variants in the genome do, perhaps because they have been exposed to population-specific natural selection. To assess this hypothesis empirically, we analyzed data from two groups of single-nucleotide polymorphisms (SNPs) that have shown reproducible (n = 9) or reported (n = 39) associations with common diseases. We compared the frequency differentiation (between Europeans and Africans) of the disease-associated SNPs with that of random SNPs in the genome. These common-disease-associated SNPs are not significantly more differentiated across populations than random SNPs. Thus, for the data examined here, ethnicity will not be a good predictor of genotype at many common-disease-associated SNPs, just as it is rarely a good predictor of genotype at random SNPs in the genome.     

Broad and Gag-biased HIV-1 epitope repertoires are associated with lower viral loads

Background

HLA class-I alleles differ in their ability to control HIV replication through cell-mediated immune responses. No consistent associations have been found between the breadth of Cytotoxic T Lymphocytes (CTL) responses and the control of HIV-1, and it is unknown whether the size or distribution of the viral proteome-wide epitope repertoire, i.e., the intrinsic ability to present fewer, more or specific viral epitopes, could affect clinical markers of disease progression.

Methodology/Principal Findings

We used an epitope prediction model to identify all epitope motifs in a set of 302 HIV-1 full-length proteomes according to each individual''s HLA (Human Leukocyte Antigen) genotype. The epitope repertoire, i.e., the number of predicted epitopes per HIV-1 proteome, varied considerably between HLA alleles and thus among individual proteomes. In a subgroup of 270 chronically infected individuals, we found that lower viral loads and higher CD4 counts were associated with a larger predicted epitope repertoire. Additionally, in Gag and Rev only, more epitopes were restricted by alleles associated with low viral loads than by alleles associated with higher viral loads.

Conclusions/Significance

This comprehensive analysis puts forth the epitope repertoire as a mechanistic component of the multi-faceted HIV-specific CTL response. The favorable impact on markers of disease status of the propensity to present more HLA binding peptides and specific proteins gives impetus to vaccine design strategies that seek to elicit responses to a broad array of HIV-1 epitopes, and suggest a particular focus on Gag.     

Lysozyme‐associated bactericidal activity in the ejaculate of a wild passerine

Numerous antibacterial substances have been identified in the ejaculates of animals and are suggested to protect sperm from bacterial‐induced damage in both the male and female reproductive tracts. Lysozymes, enzymes that exhibit bactericidal activity through their ability to break down bacterial cell walls, are likely to be particularly important for sperm defence as they are part of the constitutive innate immune system and are thus immediately available to protect sperm from bacterial attack. Birds are an ideal model for studies of ejaculate antimicrobial defences because of the dual function of the avian cloaca (i.e. waste excretion and sperm transfer), yet the antibacterial activity of avian ejaculates remains largely unexplored, and data on ejaculate lysozyme levels are only available for the domestic turkey (Meleagris gallopavo). Moreover, ejaculate lysozyme levels have not been reported for any species in the wild; which many argue is necessary to gain a comprehensive understanding of the function and dynamics of immune responses. Here, we show that lysozyme is present in the ejaculate of a wild passerine, the superb fairy‐wren (Malurus cyaneus), and that the concentration of lysozyme in ejaculates varies substantially among males. This variation, however, is not associated with male condition, sperm quality or plumage coloration. Nevertheless, we suggest that lysozyme‐associated antibacterial activity in ejaculates may be the target of natural and sexual selection and that these enzymes are likely to function in defending avian sperm from bacterial‐induced damage. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 92–100.     

Single-layer centrifugation with Androcoll-E can be scaled up to allow large volumes of stallion ejaculate to be processed easily

The objective of the current study was to optimize the volumes of Androcoll-E and sperm sample used in various sizes of centrifuge tube to scale up single-layer centrifugation (SLC) for routine use in the field. Although sperm suspensions of equivalent quality were produced using Androcoll-E in small and large tubes, the sperm yield was much lower in the latter (P < 0.001). In contrast, in 200-mL tubes (XL), the yields were approximately 25% higher than those for the small tubes. An increased volume (4.5 mL) of extended ejaculate in small tubes (SLC-Inc) or 15 to 18 mL extended ejaculate on 15 mL of colloid of a reduced density, Androcoll-E-Large (SLC-Large), in 50-mL tubes were both found to give similar yields of motile spermatozoa as that of the SLC-Small method (SLC-Small, 49.7 ± 18.6%; SLC-Inc, 53.3 ± 17.1%; SLC-Large, 44.9 ± 18.3%) and were found to be equivalent in quality (motility: 88.0 ± 8.8%, 84.0 ± 3.5%, 90.0 ± 5.4%; normal morphology: 69.4 ± 17.0%, 69.4 ± 12.7%, 63.9 ± 15.6%; viability: 78 ± 16.7%, 83.8 ± 12.5%, 80.05 ± 14.6%; DNA fragmentation index: 14.7 ± 10.9%, 12.8 ± 8.1%, 11.6 ± 7.6%, respectively). The processing of an “average” stallion Equus caballus ejaculate in approximately twenty-seven 10-mL tubes (SLC-Inc) or eight 50-mL tubes (SLC-Large) is feasible, the latter being considered more practical for on-stud use.     

High immunoglobulin-M levels to oxidation-specific epitopes are associated with lower risk of acute myocardial infarction

Immunoglobulin M (IgM) autoantibodies to oxidation-specific epitopes (OSEs) can be present at birth and protect against atherosclerosis in experimental models. This study sought to determine whether high titers of IgM titers to OSE (IgM OSE) are associated with a lower risk of acute myocardial infarction (AMI) in humans. IgM to malondialdehyde (MDA)-LDL, phosphocholine-modified BSA, IgM apolipoprotein B100-immune complexes, and a peptide mimotope of MDA were measured within 24 h of first AMI in 4,559 patients and 4,617 age- and sex-matched controls in the Pakistan Risk of Myocardial Infarction Study. Multivariate-adjusted logistic regression was used to estimate odds ratio (OR) and 95% confidence interval for AMI. All four IgM OSEs were lower in AMI versus controls (P < 0.001 for all). Males, smokers and individuals with hypertension and diabetes had lower levels of all four IgM OSE than unaffected individuals (P < 0.001 for all). Compared to the lowest quintile, the highest quintiles of IgM MDA-LDL, phosphocholine-modified BSA, IgM apolipoprotein B100-immune complexes, and MDA mimotope P1 had a lower OR of AMI: OR (95% confidence interval) of 0.67 (0.58–0.77), 0.64 (0.56–0.73), 0.70 (0.61–0.80) and 0.72 (0.62–0.82) (P < 0.001 for all), respectively. Upon the addition of IgM OSE to conventional risk factors, the C-statistic improved by 0.0062 (0.0028–0.0095) and net reclassification by 15.5% (11.4–19.6). These findings demonstrate that IgM OSE provides clinically meaningful information and supports the hypothesis that higher levels of IgM OSE may be protective against AMI.     

Relative predicted protein levels of functionally associated proteins are conserved across organisms

We show that the predicted protein levels of functionally related proteins change in a coordinated fashion over many unicellular organisms. For each protein, we created a profile containing a protein abundance measure in each of a set of organisms. We show that for functionally related proteins these profiles tend to be correlated. Using the Codon Adaptation Index as a predictor of protein abundance in 48 unicellular organisms, we demonstrated this phenomenon for two types of functional relations: for proteins that physically interact and for proteins involved in consecutive steps within a metabolic pathway. Our results suggest that the protein abundance levels of functionally related proteins co-evolve.     

Intrinsic segments of band 3 that are associated with anion transport across red blood cell membranes

Summary After treatment of red cell ghosts with chymotrypsin, the predominant intrinsic peptides remaining in the membrane fraction are 15,000 and 9,000 daltons mol wt. After partial extraction with Triton X-100, the residual membrane vesicles have almost no other stained peptides and such vesicles are reported to carry out anion transport activities sensitive to specific inhibitors. In vesicles derived from cells treated with DIDS(4,4-diisothiocyano-2,2-stilbene disulfonic acid), an irreversible inhibitor of anion transport that is highly localized in an abundant intrinsic protein known as band 3, the probe is largely recovered in the 15,000 dalton peptide. The part of band 3 from which it is derived is a previously reported 17,000 transmembrane segment (Steck, T.L., Ramos, R., Strapazon, E., 1976,Biochemistry 15:1154). The 9,000-dalton peptide is present in the vesicles in a one-to-one mole ratio with the 15,000-dalton peptide, suggesting that both are derived from the same protein. This conclusion is supported by the finding that the 35,000-dalton C-terminal end of band 3, derived by chymotrypsin treatment of cells, is further proteolysed if the cells are converted to ghosts and its disappearance coincides with the appearance of the 9,000-dalton fragment. Evidence is presented that the 9,000-dalton fragment crosses the bilayer and that it is closely associated with the 15,000-dalton peptide.This paper is dedicated to the memory of Walther Wilbrandt.     

Higher ghrelin and lower leptin secretion are associated with lower LH secretion in young amenorrheic athletes compared with eumenorrheic athletes and controls

Amenorrhea is common in young athletes and is associated with low fat mass. However, hormonal factors that link decreased fat mass with altered gonadotropin pulsatility and amenorrhea are unclear. Low levels of leptin (an adipokine) and increased ghrelin (an orexigenic hormone that increases as fat mass decreases) impact gonadotropin pulsatility. Studies have not examined luteinizing hormone (LH) secretory dynamics in relation to leptin or ghrelin secretory dynamics in adolescent and young adult athletes. We hypothesized that 1) young amenorrheic athletes (AA) would have lower LH and leptin and higher ghrelin secretion than eumenorrheic athletes (EA) and nonathletes and 2) higher ghrelin and lower leptin would be associated with lower LH secretion. This was a cross-sectional study. We examined ghrelin and leptin secretory patterns (over 8 h, from 11 PM to 7 AM) in relation to LH secretory patterns in AA, EA, and nonathletes aged 14-21 yr. Ghrelin and leptin were assessed every 20 min and LH every 10 min. Groups did not differ for age, bone age, or BMI. However, fat mass was lower in AA than in EA and nonathletes. AA had lower LH and higher ghrelin pulsatile secretion and AUC than nonathletes and lower leptin pulsatile secretion and AUC than EA and nonathletes. Percent body fat was associated positively with LH and leptin secretion and inversely with ghrelin. In a regression model, ghrelin and leptin secretory parameters were associated independently with LH secretory parameters. We conclude that higher ghrelin and lower leptin secretion in AA related to lower fat mass may contribute to altered LH pulsatility and amenorrhea.     

Adjustment of sperm allocation under high risk of sperm competition across taxa: a meta-analysis

Sperm competition theory predicts that under high risk of sperm competition, males will increase the number of sperm that they allocate to a female. This prediction has been supported by some experimental studies but not by others. Here, I conducted a meta-analysis to determine whether the increase in sperm allocation under high risk of sperm competition is a generalized response across taxa. I collected data from 39 studies and 37 species. Across taxa, males under a high risk of sperm competition respond by increasing their sperm allocation (mean effect size=0.32). Number of offspring did not explain a significant portion of the variation in effect sizes. A traditional meta-analysis (i.e. without phylogenetic information) described the variation among effect sizes better than a meta-analysis that incorporates the phylogenetic relationships among species, suggesting that the increase in sperm allocation under high risk of sperm competition is similarly prevalent across taxa.