Our current understanding of the operation of sexual selection is predicated on a sex difference in parental investment, which favours one sex becoming limiting and choosy over mates, the other competitive and nonchoosy. This difference is reflected in the operational sex ratio (OSR), the ratio of sexually receptive males to females, considered to be of fundamental importance in predicting the direction of sexual selection. Difficulties in measuring OSR directly have led to the use of the potential reproductive rates (PRR) as a measure of the level of investment in offspring of males and females. Several recent studies have emphasized that other factors, such as variation in mate quality and sex differences in mortality patterns, also influence the direction of sexual selection. However, as yet there has been no attempt to form a comprehensive theory of sex roles. Here we show that neither OSR nor PRR is the most fundamentally important determinant of sex roles, and that they are not interchangeable. Instead, the cost of a single breeding attempt has a strong direct effect on competition and choosiness as well as consistent relationships to both OSR and PRR. Our life history based approach to mate choice also yields simple, testable predictions on lack of choice in either sex and on mutual mate choice.

Background: Surgical mortality data are collected routinely in high-income countries, yet virtually no low-or middle-income countries have outcome surveillance in place. The aim was prospectively to collect worldwide mortality data following emergency abdominal surgery, comparing findings across countries with a low, middle or high Human Development Index (HDI).Methods: This was a prospective, multicentre, cohort study. Self-selected hospitals performing emergency surgery submitted prespecified data for consecutive patients from at least one 2-week interval during July to December 2014. Postoperative mortality was analysed by hierarchical multivariable logistic regression.

Gremlin1 has a distinct preference for which bone morphogenetic protein it binds to in kidney epithelial cells. Grem1–BMP-2 complexes are favoured over other BMPs, and this may play an important role in fibrotic kidney disease.

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It is well known that lysine acetylation (Kace) modification is a common post-translational modification (PTM) that plays an important role in multiple biological and pathological functions in bacteria. However, few studies have focused on lysine acetylation modification in aquatic pathogens to date. In this study, the acetylome profiling of fish pathogen, Vibrio alginolyticus was investigated by combining affinity enrichment with LC MS/MS. A total of 2883 acetylation modification sites on 1178 proteins in this pathogen were identified. The Kace modification of several selected proteins were further validated by Co-immunocoprecipitation combined with Western blotting. Bioinformatics analysis showed that seven conserved motifs can be enriched among Kace peptides, and many of them were significantly enriched in metabolic processes such as biosynthesis of secondary metabolites, microbial metabolism in diverse environments, and biosynthesis of amino acids, which was similar to data previously published for V. parahaemolyticus. Moreover, we found at least 102 acetylation modified proteins predicted as virulence factors, which indicate the important role of PTM on bacterial virulence. In general, our results provide a promising starting point for further investigations of the biological role of lysine acetylation on bacterial virulence in V. alginolyticus.

BackgroundThe salmon louse, Lepeophtheirus salmonis, is an ectoparasitic copepod which feeds on the mucus, skin and blood of salmonid fish species. The parasite can persist on the surface of the fish without any effective control being exerted by the host immune system. Other ectoparasitic invertebrates produce compounds in their saliva, excretions and/or secretions which modulate the host immune responses allowing them to remain on or in the host during development. Similarly, compounds are produced in secretions of L. salmonis which are thought to be responsible for immunomodulation of the host responses as well as other aspects of crucial host-parasite interactions.MethodsIn this study we have identified and characterised the proteins in the excretory/secretory (E/S) products of L. salmonis using LC-ESI-MS/MS.ResultsIn total 187 individual proteins were identified in the E/S collected from adult lice and pre-adult sea lice. Fifty-three proteins, including 13 serine-type endopeptidases, 1 peroxidase and 5 vitellogenin-like proteins were common to both adult and pre-adult E/S products. One hundred and seven proteins were identified in the adult E/S but not in the pre-adult E/S and these included serine and cysteine-type endopeptidases, vitellogenins, sphingomyelinase and calreticulin. A total of 27 proteins were identified in pre-adult E/S products but not in adult E/S.ConclusionsThe assigned functions of these E/S products and the potential roles they play in host-parasite interaction is discussed.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-2885-6) contains supplementary material, which is available to authorized users.

Koi herpesvirus (KHV) causes an economically important, highly infectious disease in common carp and koi, Cyprinus carpio L. Since the occurrence of mass mortalities worldwide, highly specific and sensitive molecular diagnostic methods have been developed for KHV detection. The sensitivity and reliability of these assays have essentially focused at the detection of low viral DNA copy numbers during latent or persistent infections. However, the efficacy of these assays has not been investigated with regard to low-level viraemia during acute infection stages. This study was conducted to compare the sensitivity of seven different polymerase chain reaction (PCR) assays to detect KHV during the first hours and days post-infection (hpi; dpi), using lethal and non-lethal sampling methods. The results highlight the limitations of the assays for detecting virus during the first 4 dpi despite rapid mortality in experimentally infected carp. False-negative results were associated with time post-infection and the tissue sampled. Non-lethal sampling appears effective for KHV screening, with efficient detection in mucus samples obtained from external swabs during this early infection period (<5 dpi), while biopsies from gills and kidney were negative using the same PCR assays. Non-lethal sampling may improve the reliability of KHV detection in subclinical, acutely infected carp.

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