What makes wild chimpanzees wake up at night?

I examined the possible cause of night awakening among wild chimpanzees (Pan troglodytes) in Mahale Mountains National Park, Tanzania. Chimpanzee vocalizations and activity-related sounds (CVSs) were used to indicate awakening because I was unable to visually observe them. Over a 5-night observation period, CVSs (n = 128) were heard every night, and most (n = 91) were observed within 5 min of previous CVSs. Chimpanzees use CVSs as social communication to maintain spatial contact with other chimpanzees who occasionally travel at night. The first sound in a sequence of CVSs (CVS bout) was heard immediately following the vocalization or sound of another animal (n = 11), defecation or urination by a chimpanzee (n = 7), or unknown (n = 19). CVS bouts were longer when preceded by defecation or urination than when preceded by the vocalization or sound of other animals or an unknown factor. This suggests that the degree of wakefulness varies according to the possible cause of the disturbance. CVSs at night may be provoked by various factors, and awakening during the night is probably common among diurnal primates.     

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 us human?

The sequence of chimpanzee chromosome 22 is starting to help us to define the set of genetic attributes that are unique to humans, but interpreting the biological consequences of these remains a major challenge.     

What makes desiccation tolerable?

A comparison of drought tolerance in plants at extreme ends of the evolutionary spectrum is beginning to show the mechanisms involved.     

What makes the cell differentiate?

In the present paper, I propose a hypothesis whereby the necessity to maintain the permanent energy-dissipating metabolic flux represents the primary force that determines the eukaryotic cell's choice to grow, divide and/or differentiate. This view is based on the universal structure and the strict redox neutrality of the core metabolic network. I propose that the direct substrate level coupling between metabolism and gene expression through epigenetic mechanisms provides a mechanistic explanation of how this control is implemented.     

What makes ecological systems reactive?

Although perturbations from a stable equilibrium must ultimately vanish, they can grow initially, and the maximum initial growth rate is called reactivity. Reactivity thus identifies systems that may undergo transient population surges or drops in response to perturbations; however, we lack biological and mathematical intuition about what makes a system reactive. This paper presents upper and lower bounds on reactivity for an arbitrary linearized model, explores their strictness, and discusses their biological implications. I find that less stable systems (i.e. systems with long transients) have a smaller possible range of reactivities for which no perturbations grow. Systems with more species have a higher capacity to be reactive, assuming species interactions do not weaken too rapidly as the number of species increases. Finally, I find that in discrete time, reactivity is determined largely by mean interaction strength and neither discrete nor continuous time reactivity are sensitive to food web topology.     

What makes bacterial pathogens so sticky?

Pathogenic bacteria use a variety of cell surface adhesins to promote binding to host tissues and protein-coated biomaterials, as well as cell–cell aggregation. These cellular interactions represent the first essential step that leads to host colonization and infection. Atomic force microscopy (AFM) has greatly contributed to increase our understanding of the specific interactions at play during microbial adhesion, down to the single-molecule level. A key asset of AFM is that adhesive interactions are studied under mechanical force, which is highly relevant as surface-attached pathogens are often exposed to physical stresses in the human body. These studies have identified sophisticated binding mechanisms in adhesins, which represent promising new targets for antiadhesion therapy.     

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 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.