The highly diverged trypanosomal MICOS complex is organized in a nonessential integral membrane and an essential peripheral module

The mitochondrial contact site and cristae organization system (MICOS) mediates the formation of cristae, invaginations in the mitochondrial inner membrane. The highly diverged MICOS complex of the parasitic protist Trypanosoma brucei consists of nine subunits. Except for two Mic10‐like and a Mic60‐like protein, all subunits are specific for kinetoplastids. Here, we determined on a proteome‐wide scale how ablation of individual MICOS subunits affects the levels of the other subunits. The results reveal co‐regulation of TbMic10‐1, TbMic10‐2, TbMic16 and TbMic60, suggesting that these nonessential, integral inner membrane proteins form an interdependent network. Moreover, the ablation of TbMic34 and TbMic32 reveals another network consisting of the essential, intermembrane space‐localized TbMic20, TbMic32, TbMic34 and TbMic40, all of which are peripherally associated with the inner membrane. The downregulation of TbMic20, TbMic32 and TbMic34 also interferes with mitochondrial protein import and reduces the size of the TbMic10‐containing complexes. Thus, the diverged MICOS of trypanosomes contains two subcomplexes: a nonessential membrane‐integrated one, organized around the conserved Mic10 and Mic60, that mediates cristae formation, and an essential membrane‐peripheral one consisting of four kinetoplastid‐specific subunits, that is required for import of intermembrane space proteins.     

Tropical rainforest flies carrying pathogens form stable associations with social nonhuman primates

Living in groups provides benefits but also incurs costs such as attracting disease vectors. For example, synanthropic flies associate with human settlements, and higher fly densities increase pathogen transmission. We investigated whether such associations also exist in highly mobile nonhuman primate (NHP) Groups. We studied flies in a group of wild sooty mangabeys (Cercocebus atys atys) and three communities of wild chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d'Ivoire. We observed markedly higher fly densities within both mangabey and chimpanzee groups. Using a mark–recapture experiment, we showed that flies stayed with the sooty mangabey group for up to 12 days and for up to 1.3 km. We also tested mangabey‐associated flies for pathogens infecting mangabeys in this ecosystem, Bacillus cereus biovar anthracis (Bcbva), causing sylvatic anthrax, and Treponema pallidum pertenue, causing yaws. Flies contained treponemal (6/103) and Bcbva (7/103) DNA. We cultured Bcbva from all PCR‐positive flies, confirming bacterial viability and suggesting that this bacterium might be transmitted and disseminated by flies. Whole genome sequences of Bcbva isolates revealed a diversity of Bcbva, probably derived from several sources. We conclude that flies actively track mangabeys and carry infectious bacterial pathogens; these associations represent an understudied cost of sociality and potentially expose many social animals to a diversity of pathogens.     

Thermal stability of single‐domain antibodies estimated by molecular dynamics simulations

Single‐domain antibodies (sdAbs) function like regular antibodies, however, consist of only one domain. Because of their low molecular weight, sdAbs have advantages with respect to production and delivery to their targets and for applications such as antibody drugs and biosensors. Thus, sdAbs with high thermal stability are required. In this work, we chose seven sdAbs, which have a wide range of melting temperature (T_m) values and known structures. We applied molecular dynamics (MD) simulations to estimate their relative stability and compared them with the experimental data. High‐temperature MD simulations at 400 K and 500 K were executed with simulations at 300 K as a control. The fraction of native atomic contacts, Q, measured for the 400 K simulations showed a fairly good correlation with the T_m values. Interestingly, when the residues were classified by their hydrophobicity and size, the Q values of hydrophilic residues exhibited an even better correlation, suggesting that stabilization is correlated with favorable interactions of hydrophilic residues. Measuring the Q value on a per‐residue level enabled us to identify residues that contribute significantly to the instability and thus demonstrating how our analysis can be used in a mutant case study.     

A Centipede Toxin Family Defines an Ancient Class of CSαβ Defensins

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Exon Inclusion Modulates Conformational Plasticity and Autoinhibition of the Intersectin 1 SH3A Domain

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Role of school climate and personality in the development of Czech adolescents’ political self-efficacy

This study examined the effects of school climate (open classroom and positive student relationships) and personality dispositions (shyness and need for cognition) on adolescents’ political self-efficacy. Data were collected in 2014 from 1,954 Czech ninth- and tenth-graders (mean age?=?15.60). A multilevel analysis showed that school-level political self-efficacy predicted self-efficacy for local politics. However, schools and classrooms were rather homogeneous in terms of students’ mean political self-efficacy and students’ self-reported acquisition of civic skills at school. Hence, school characteristics had only limited associations with adolescents’ political self-efficacy. At the same time, students’ political efficacy had a considerable association with lower shyness and higher need for cognition. These results suggest that the development of political efficacy at school goes beyond simple general influences of school environment and individual differences between students must be considered.     

Grey mould of strawberry,a devastating disease caused by the ubiquitous necrotrophic fungal pathogen Botrytis cinerea

The fungal pathogen Botrytis cinerea causes grey mould, a commercially damaging disease of strawberry. This pathogen affects fruit in the field, storage, transport and market. The presence of grey mould is the most common reason for fruit rejection by growers, shippers and consumers, leading to significant economic losses. Here, we review the biology and epidemiology of the pathogen, mechanisms of infection and the genetics of host plant resistance. The development of grey mould is affected by environmental and genetic factors; however, little is known about how B. cinerea and strawberry interact at the molecular level. Despite intensive efforts, breeding strawberry for resistance to grey mould has not been successful, and the mechanisms underlying tolerance to B. cinerea are poorly understood and under-investigated. Current control strategies against grey mould include pre- and postharvest fungicides, yet they are generally ineffective and expensive. In this review, we examine available research on horticultural management, chemical and biological control of the pathogen in the field and postharvest storage, and discuss their relevance for integrative disease management. Additionally, we identify and propose approaches for increasing resistance to B. cinerea in strawberry by tapping into natural genetic variation and manipulating host factors via genetic engineering and genome editing.     

A fundamental difference between macrobiota and microbial eukaryotes: protistan plankton has a species maximum in the freshwater-marine transition zone of the Baltic Sea

Remane's Artenminimum at the horohalinicum is a fundamental concept in ecology to describe and explain the distribution of organisms along salinity gradients. However, a recent metadata analysis challenged this concept for protists, proposing a species maximum in brackish waters. Due to data bias, this literature-based investigation was highly discussed. Reliable data verifying or rejecting the species minimum for protists in brackish waters were critically lacking. Here, we sampled a pronounced salinity gradient along a west–east transect in the Baltic Sea and analysed protistan plankton communities using high-throughput eDNA metabarcoding. A strong salinity barrier at the upper limit of the horohalinicum and 10 psu appeared to select for significant shifts in protistan community structures, with dinoflagellates being dominant at lower salinities, and dictyochophytes and diatoms being keyplayers at higher salinities. Also in vertical water column gradients in deeper basins (Kiel Bight, Arkona and Bornholm Basin) appeared salinity as significant environmental determinant influencing alpha- and beta-diversity patterns. Importantly, alpha-diversity indices revealed species maxima in brackish waters, that is, indeed contrasting Remane's Artenminimum concept. Statistical analyses confirmed salinity as the major driving force for protistan community structuring with high significance. This suggests that macrobiota and microbial eukaryotes follow fundamentally different rules regarding diversity patterns in the transition zone from freshwater to marine waters.     

Strikingly high levels of heterozygosity despite 20 years of inbreeding in a clonal honey bee

Inbreeding (the mating between closely related individuals) often has detrimental effects that are associated with loss of heterozygosity at overdominant loci, and the expression of deleterious recessive alleles. However, determining which loci are detrimental when homozygous, and the extent of their phenotypic effects, remains poorly understood. Here, we utilize a unique inbred population of clonal (thelytokous) honey bees, Apis mellifera capensis, to determine which loci reduce individual fitness when homozygous. This asexual population arose from a single worker ancestor approximately 20 years ago and has persisted for at least 100 generations. Thelytokous parthenogenesis results in a 1/3 of loss of heterozygosity with each generation. Yet, this population retains heterozygosity throughout its genome due to selection against homozygotes. Deep sequencing of one bee from each of the three known sub‐lineages of the population revealed that 3,766 of 10,884 genes (34%) have retained heterozygosity across all sub‐lineages, suggesting that these genes have heterozygote advantage. The maintenance of heterozygosity in the same genes and genomic regions in all three sub‐lineages suggests that nearly every chromosome carries genes that show sufficient heterozygote advantage to be selectively detrimental when homozygous.