What makes a mitochondrion?

Experimental analyses of the proteins found in the mitochondria of yeast, humans and Arabidopsis have confirmed some expectations but given some surprises and some insights into the evolutionary origins of mitochondrial proteins.     

What makes an urban bird?

Urban development is increasing across the globe. This poses a major threat to biodiversity, which is often relatively poor in towns and cities. Despite much interest in identifying species' traits that can predict their responses to environmental degradation this approach has seldom been used to assess which species are particularly vulnerable to urban development. Here we explore this issue, exploiting one of the best available datasets on species' responses to towns and cities in a highly urbanized region, comprising avian densities across approximately 3000 British urban and rural 1 km × 1 km grid cells. We find that the manner in which species' responses to urbanization is measured has a marked influence on the nature of associations between these responses and species' ecological and life history traits. We advocate that future studies should use continuous indices of responses that take relative urban and rural densities into account, rather than using urban densities in isolation, or a binary response recording the presence/absence of a species in towns and cities. Contrary to previous studies we find that urban development does not select against avian long‐distance migrants and insectivores, or species with limited annual fecundity and dispersal capacity. There was no evidence that behavioural flexibility, as measured by relative brain size, influenced species' responses to urban environments. In Britain, generalist species, as measured by niche position rather than breadth, are favoured by urban development as are, albeit to a lesser extent, those that feed on plant material and nest above the ground. Our results suggest that avian biodiversity in towns and cities in urbanizing regions will be promoted by providing additional resources that are currently scarce in urban areas, and developing suitable environments for ground‐nesting species.     

What happens between an external stimulus and an overt response? A study of covert behavior.

Peripheral components of feedthrough loops were psychophysiologically measured from the brain, both forelimbs, the tongue and the eyes during simple and choice reaction time tasks using linguistic and non-linguistic stimuli. Closing a microswitch with the little finger was the overt response. Covert electromyographic (EMG) responses were computer identified in the following average temporal order: generally, the earliest covert reactions were in the tongue, brain, eyes, and passive arm-hand region. Next were complex EMG events in the active limb. These covert reactions may function in feedthrough loops to generate and transmit codes during internal information processing. The passive arm-hand responses occurred significantly earlier than the onset of the covert EMG burst for closing the microswitch; perhaps there is an inhibitory response "commanding" the passive arm not to respond, before the other (active) limb can overtly respond. Mean response patterns to linguistic and non-linguistic stimuli were almost identical. Reaction time to the onset of the EMG burst for switch closing was from 40 to 95 milliseconds earlier than the usual overt reaction time measure (that to switch closing), suggesting that reaction time studies might be improved by using the onset of EMG increase as the more sensitive and precise measure.     

What makes a specialized endophyte special?

Fungal plant symbionts can be highly specialized on a limited range of host genotypes and species. Understanding the genetic basis of this specialization, the mechanisms governing its establishment and the relationship between specialization and speciation is a major challenge for evolutionary biologists (Timms & Read, 1999 ). A deeper knowledge of evolutionary plant–microbe interactions could be exploited to improve agricultural management, by bringing fungal biodiversity and fungal biomass under greater and more durable human control. Previous studies on pathogens have shown that effectors, that is, small secreted proteins that modulate plant physiology to favour host colonization, play a key role in infection of novel hosts (e.g., Inoue et al., 2017 ) or in host specialization (e.g., Liao et al. ( 2016 )). Like pathogens, endophytes also manipulate the physiology of their hosts and colonize novel hosts to which they specialize (Hardoim et al., 2015 ). These biological characteristics of endophytes raise the question of similarities in the protein arsenal contributing to the specialization of pathogens and endophytes. In this issue of Molecular Ecology, Schirrmann et al. ( 2018 ) used a combination of divergence genome scans and tests for positive selection to investigate the genetic basis of specialization of two subspecies of the symbiont Epichloë typhina occurring on two different grass hosts. Their analyses suggest a key role of effectors as determinants of host specialization. This study paves the way towards the comparative analysis of the genomics of speciation among plant symbionts.     

What makes an endurance athlete world-class? Not simply a physiological conundrum

Inter-individual variation in endurance performance capacity is a characteristic, not only of the general population, but also in trained athletes. The ability of sport scientists to predict which athletes amongst an elite group will become world-class is limited. We do not fully understand the interactions between biological factors, training, recovery and competitive performance. Assessment methods and interpretation of results do not take into account the facts that most research is not done on elite athletes and performances of world-class endurance athletes cannot be attributed to aerobic capacity alone. Many lines of evidence suggest that there is a limit to adaptation in aerobic capacity. Recent advances in molecular biology and genetics should be harnessed by exercise biologists in conjunction with previously used physiological, histological and biochemical techniques to study elite athletes and their responses to different training and recovery regimens. Technological advances should be harnessed to study world-class athletes to determine optimal training and competition strategies. In summary, it is likely that multiple factors are essential contributors to world-class endurance performance and that it is only by using a multidisciplinary approach that we will come closer to solving the conundrum: 'What makes an endurance athlete world class?'     

What makes a fly enter diapause?

Diapause is a dormant state that insects may undergo as a response to changing environmental conditions. In flies, like many insects inhabiting temperate zones, diapause occurs generally during the winter months when ambient temperatures are cool and food sources scarce. Whilst the environmental factors involved in determining diapause have been known for a long time, the genes and molecular events controling its initiation are poorly understood. Here I outline the factors that initiate diapause and highlight recent studies that implicate insulin signaling in its control.     

What makes a successful biocontrol agent? A meta-analysis of biological control agent performance

We qualitatively reviewed the biocontrol literature in two major journals, Biological Control and Environmental Entomology, over the past 10 years by scoring 878 studies into 11 biocontrol-oriented questions. Quantitative meta-analyses were then used on data from 145 studies to examine the effects of different types of biocontrol agents (parasitoids, predators, and pathogens) on several attributes of weed and pest populations. Results for our qualitative review showed that most biocontrol studies were focused on lepidopteran pests, and that parasitoids were the most common biocontrol agents used. Our quantitative review showed that, for weeds, biocontrol agents significantly reduced weed biomass (−82.0%), flower (−98.9%), and seed production (−89.4%). For pests, our quantitative review showed that biocontrol agents significantly reduced pest abundance by 130% compared to control groups, increased parasitism (+139.0%) and increased overall pest mortality (+159.0%) compared to targets not exposed to biocontrol agents. Effects on pest mortality tended to be stronger for parasitoids than predators, although reductions caused in pest abundance were much stronger when predators were used as biocontrol agents. Addition of two or more biocontrol agents increased mortality by 12.97% and decreased pest abundance by 27.17% compared to single releases. Separate sets of meta-analyses demonstrated that the negative impacts of biocontrol on non-target species were much smaller than those for target species, although adverse effects of biocontrol on non-target organisms are based on small sample sizes and should be interpreted with caution. Our results also showed that biocontrol efficacy tended to be higher when agents were generalists than when they were specialists. Large fail–safe numbers found for most of the estimated effects indicate the robustness of the results found for the efficacy of biological control programs.     

What makes a binding site a binding site?

Organic probe molecules have recently been used to define hydrophobic binding sites on the surface of proteins. It appears that the presence of water on the surface of a protein plays a crucial role in the interaction between that protein and its binding site.     

What factors shape rates of phenotypic evolution? A comparative study of cranial morphology of four mammalian clades

Understanding why rates of morphological evolution vary is a major goal in evolutionary biology. Classical work suggests that body size, interspecific competition, geographic range size and specialization may all be important, and each may increase or decrease rates of evolution. Here, we investigate correlates of proportional evolutionary rates in phalangeriform possums, phyllostomid bats, platyrrhine monkeys and marmotine squirrels, using phylogenetic comparative methods. We find that the most important correlate is body size. Large species evolve the fastest in all four clades, and there is a nonlinear relationship in platyrrhines and phalangeriformes, with the slowest evolution in species of intermediate size. We also find significant increases in rate with high environmental temperature in phyllostomids, and low mass-specific metabolic rate in marmotine squirrels. The mechanisms underlying these correlations are uncertain and appear to be size specific. We conclude that there is significant variation in rates of evolution, but that its meaning is not yet clear.     

What makes a cell face selective? The importance of contrast

Faces are robustly detected by computer vision algorithms that search for characteristic coarse contrast features. Here, we investigated whether face-selective cells in the primate brain exploit contrast features as well. We recorded from face-selective neurons in macaque inferotemporal cortex, while presenting?a face-like collage of regions whose luminances were changed randomly. Modulating contrast combinations between regions induced activity changes ranging from no response to a response greater than that to a real face in 50% of cells. The critical stimulus factor determining response magnitude was contrast polarity, for example, nose region brighter than left eye. Contrast polarity preferences were consistent across cells, suggesting a common computational strategy across the population, and matched features used by computer vision algorithms for face detection. Furthermore, most cells were tuned both for contrast polarity and for the geometry of facial features, suggesting cells encode information useful both for detection and recognition.     

Is ethnicity a meaningful category of employment policies for Roma? A comparative case study of Hungary and Spain

This paper aims to inquire into the potential of active labour market policies (LMP) to reach out to unemployed Roma population in Hungary and in Spain. While in Hungary unemployed Roma people are mainly thought to be reached through mainstream measures, Spain represents a more complex regime with an emphasis on ethnically targeted programmes. Our analysis draws on a wider comparative research project (NEUJOBS) conducted in 2012/2013 and provides an insight into how LMP function locally for unemployed Roma. We conclude that there are two intersecting challenges regarding the success of LMP that aim to influence the employment situation of the Roma: the targeting strategies and the quality and complexity of the programmes’ design. Our empirical data suggest that both aspects need to be given equal attention in order to promote the inclusion of the Roma into the labour market.