Abundance and functional roles of intrinsic disorder in the antimicrobial peptides of the NK-lysin family

NK-lysins are antimicrobial peptides (AMPs) that participate in the innate immune response and also have several pivotal roles in various biological processes. Such multifunctionality is commonly found among intrinsically disordered proteins. However, NK-lysins have never been systematically analyzed for intrinsic disorder. To fill this gap, the amino acid sequences of NK-lysins from various species were collected from UniProt and used for the comprehensive computational analysis to evaluate the propensity of these proteins for intrinsic disorder and to investigate the potential roles of disordered regions in NK-lysin functions. We analyzed abundance and peculiarities of intrinsic disorder distribution in all-known NK-lysins and showed that many NK-lysins are expected to have substantial levels of intrinsic disorder. Curiously, high level of intrinsic disorder was also found even in two proteins with known 3D-strucutres (NK-lysin from pig and human granulysin). Many of the identified disordered regions can be involved in protein–protein interactions. In fact, NK-lysins are shown to contain three to eight molecular recognition features; i.e. short structure-prone segments which are located within the long disordered regions and have a potential to undergo a disorder-to-order transition upon binding to a partner. Furthermore, these disordered regions are expected to have several sites of various posttranslational modifications. Our study shows that NK-lysins, which are AMPs with a set of prominent roles in the innate immune response, are expected to abundantly possess intrinsically disordered regions that might be related to multifunctionality of these proteins in the signal transduction pathways controlling the host response to pathogenic agents.     

Circulating glutathione concentrations in marine,semiaquatic, and terrestrial mammals

An important low molecular weight antioxidant in biological systems is glutathione; its efficiency depends on the equilibrium between its reduced (GSH) and oxidized (GSSG) forms. The oxidized:total glutathione (GSSG:GSH‐Eq) ratio can be used as an indicator of oxidative stress. Previous studies suggest that marine mammals, unlike terrestrial mammals, do not show adverse effects in tissues exposed to ischemia/reperfusion during the peripheral vasoconstriction associated with breath‐hold diving. This is due, in part, to higher antioxidant enzyme activities in marine mammals compared with terrestrial mammals. The objective of this study was to compare circulating glutathione levels among mammals with different diving capacities. Circulating GSH‐Eq, GSH, and GSSG concentrations in erythrocyte samples from northern elephant seals (Mirounga angustirostris), bottlenose dolphins (Tursiops truncatus), neotropical otters (Lontra longicaudis annectens), domestic pigs (Sus scrofa), and humans were quantified using spectrophotometry. Higher GSH‐Eq and GSH concentrations and a lower GSSG:GSH‐Eq index were found in erythrocytes from northern elephant seals and bottlenose dolphins as compared to otters, domestic pigs, and humans. Results suggest that marine mammals, independent of their diving capacity, possess a highly developed antioxidant system, including GSH; continuous availability of GSH could allow these species to avoid oxidative damage and tolerate ischemia/reperfusion and hypoxia/reoxygenation events associated with diving.     

Phylogeny and taxonomy of the genus Ilyodon Eigenmann, 1907 (Teleostei: Goodeidae), based on mitochondrial and nuclear DNA sequences

Taxonomy of the live‐bearing fish of the genus Ilyodon Eigenmann, 1907 (Goodeidae), in Mexico, is controversial, with morphology and mitochondrial genetic analyses in disagreement about the number of valid species. The present study accumulated a comprehensive DNA sequences dataset of 98 individuals of all Ilyodon species and mitochondrial and nuclear loci to reconstruct the evolutionary history of the genus. Phylogenetic inference produced five clades, one with two sub‐clades, and one clade including three recognized species. Genetic distances in mitochondrial genes (cytb: 0.5%–2.1%; coxI: 0.5%–1.1% and d‐loop: 2.3%–10.2%) were relatively high among main clades, while, as expected, nuclear genes showed low variation (0.0%–0.2%), with geographic concordance and few shared haplotypes among river basins. High genetic structure was observed among clades and within basins. Our genetic analyses, applying the priority principle, suggest the recognition only of Ilyodon whitei and Ilyodon furcidens, with I. cortesae relegated to an invalid species, the populations of which belong to I. whitei.     

Ellagic acid and rosmarinic acid attenuate doxorubicin‐induced testicular injury in rats

The anticancer drug doxorubicin causes testicular toxicity as an undesirable effect. The present study was undertaken to investigate the possible protection of ellagic acid and rosmarinic acid during doxorubicin administration. For this purpose eight groups of male Sprague–Dawley rats were used (n = 10), one group received vehicle served as control, and other groups received 5 mg/kg doxorubicin twice a week for 2 weeks for a cumulative dose of 20 mg/kg, ellagic acid (10 mg/kg/day, 14 consecutive days p.o.), rosmarinic acid (75 mg/kg/day, 14 consecutive days p.o.), ellagic acid and rosmarinic acid. The latter three regimens were given to control and doxorubicin‐received rats. Doxorubicin decreased testicular relative weight, sperm count, motility, serum testosterone, testicular glycogen, and sialic acid with increased incidence of histopathological changes, oxidative stress, tumor necrosis factor‐alpha, as well as cholinesterase activity. Conversely, ellagic and rosmarinic acid treatment ameliorated such damage, thus showing the possibility to use as an adjuvant during doxorubicin treatment.     

Rhamnose synthase activity is required for pathogenicity of the vascular wilt fungus Verticillium dahliae

The initial interaction of a pathogenic fungus with its host is complex and involves numerous metabolic pathways and regulatory proteins. Considerable attention has been devoted to proteins that play a crucial role in these interactions, with an emphasis on so‐called effector molecules that are secreted by the invading microbe to establish the symbiosis. However, the contribution of other types of molecules, such as glycans, is less well appreciated. Here, we present a random genetic screen that enabled us to identify 58 novel candidate genes that are involved in the pathogenic potential of the fungal pathogen Verticillium dahliae, which causes vascular wilt diseases in over 200 dicotyledonous plant species, including economically important crops. One of the candidate genes that was identified concerns a putative biosynthetic gene involved in nucleotide sugar precursor formation, as it encodes a putative nucleotide‐rhamnose synthase/epimerase‐reductase (NRS/ER). This enzyme has homology to bacterial enzymes involved in the biosynthesis of the nucleotide sugar deoxy‐thymidine diphosphate (dTDP)‐rhamnose, a precursor of L‐rhamnose, which has been shown to be required for virulence in several human pathogenic bacteria. Rhamnose is known to be a minor cell wall glycan in fungi and has therefore not been suspected as a crucial molecule in fungal–host interactions. Nevertheless, our study shows that deletion of the VdNRS/ER gene from the V. dahliae genome results in complete loss of pathogenicity on tomato and Nicotiana benthamiana plants, whereas vegetative growth and sporulation are not affected. We demonstrate that VdNRS/ER is a functional enzyme in the biosynthesis of uridine diphosphate (UDP)‐rhamnose, and further analysis has revealed that VdNRS/ER deletion strains are impaired in the colonization of tomato roots. Collectively, our results demonstrate that rhamnose, although only a minor cell wall component, is essential for the pathogenicity of V. dahliae.     

刺芹侧耳不同发育时期的转录组差异分析

为了探讨刺芹侧耳子实体生长发育时期的基因表达变化,本文利用高通量测序技术对刺芹侧耳不同发育时期（菌丝期、原基期、子实体时期）进行RNA-Seq分析,在转录水平上解析差异表达基因在刺芹侧耳生长发育过程中的作用和功能。KEGG功能富集显示,菌丝期差异表达基因主要富集在碳代谢和氨基酸代谢中,其中三羧酸循环中编码柠檬酸合酶、乌头酸水合酶、异柠檬酸脱氢酶、琥珀酰辅酶A合成酶、琥珀酸脱氢酶、苹果酸脱氢酶的基因表达量均上调,说明碳代谢和氨基酸代谢是菌丝时期的主要能量来源;原基期上调的差异表达基因主要富集在脂肪酸代谢,其中RT-PCR定量结果显示原基期编码脂肪酸合酶的基因和编码脂酰辅酶A合成酶的基因下调,编码超氧化物酶的基因和编码过氧化氢酶的基因上调,表明脂肪酸代谢和抗氧化酶对刺芹侧耳原基期维持机体的稳定和生物应激方面起着重要作用。子实体时期上调的差异表达基因主要富集在剪接体、类固醇的生物合成以及AMPK信号通路中,说明环境因子对子实体时期有一定的影响。