Distinctive communication networks in inactive states of β2-adrenergic receptor: Mutual information and entropy transfer analysis

Mutual information and entropy transfer analysis employed on two inactive states of human beta-2 adrenergic receptor (β₂-AR) unraveled distinct communication pathways. Previously, a so-called “highly” inactive state of the receptor was observed during 1.5 microsecond long molecular dynamics simulation where the largest intracellular loop (ICL3) was swiftly packed onto the G-protein binding cavity, becoming entirely inaccessible. Mutual information quantifying the degree of correspondence between backbone-C_α fluctuations was mostly shared between intra- and extra-cellular loop regions in the original inactive state, but shifted to entirely different regions in this latest inactive state. Interestingly, the largest amount of mutual information was always shared among the mobile regions. Irrespective of the conformational state, polar residues always contributed more to mutual information than hydrophobic residues, and also the number of polar-polar residue pairs shared the highest degree of mutual information compared to those incorporating hydrophobic residues. Entropy transfer, quantifying the correspondence between backbone-C_α fluctuations at different timesteps, revealed a distinctive pathway directed from the extracellular site toward intracellular portions in this recently exposed inactive state for which the direction of information flow was the reverse of that observed in the original inactive state where the mobile ICL3 and its intracellular surroundings drove the future fluctuations of extracellular regions.     

PCR-generated conspecific sodium channel gene probe for the house fly.

A segment of the house fly (Musca domestica) homologue of the para (paralytic) sodium channel gene of Drosophila melanogaster was isolated by using mixed sequence oligonucleotide primers in the polymerase chain reaction (PCR). The specificity of the procedure was demonstrated by genomic Southern analysis using the housefly PCR amplification product as a probe and by DNA sequence analysis. The latter showed structural homology to the para gene, but not to the corresponding region of DSC1, another D. melanogaster gene with structural similarity to vertebrate sodium channel genes.     

Index of intensity of sexual selection: A comment on Nishida's article

An index of intensity of sexual selection proposed by Nishida (1992: Res. Popul. Ecol. 34: 373–382) was examined. Two examples were presented to show that Nishida's index was not free from confounding effect of mortality schedule. Importance of removing the phylogenetic effects in comparative analyses was also discussed.     

Selection analysis on the rapid evolution of a secondary sexual trait

Evolutionary analyses of population translocations (experimental or accidental) have been important in demonstrating speed of evolution because they subject organisms to abrupt environmental changes that create an episode of selection. However, the strength of selection in such studies is rarely measured, limiting our understanding of the evolutionary process. This contrasts with long-term, mark–recapture studies of unmanipulated populations that measure selection directly, yet rarely reveal evolutionary change. Here, we present a study of experimental evolution of male colour in Trinidadian guppies where we tracked both evolutionary change and individual-based measures of selection. Guppies were translocated from a predator-rich to a low-predation environment within the same stream system. We used a combination of common garden experiments and monthly sampling of individuals to measure the phenotypic and genetic divergence of male coloration between ancestral and derived fish. Results show rapid evolutionary increases in orange coloration in both populations (1 year or three generations), replicating the results of previous studies. Unlike previous studies, we linked this evolution to an individual-based analysis of selection. By quantifying individual reproductive success and survival, we show, for the first time, that males with more orange and black pigment have higher reproductive success, but males with more black pigment also have higher risk of mortality. The net effect of selection is thus an advantage of orange but not black coloration, as reflected in the evolutionary response. This highlights the importance of considering all components of fitness when understanding the evolution of sexually selected traits in the wild.     

Towards the identification of the allosteric Phe-binding site in phenylalanine hydroxylase

The enzyme phenylalanine hydroxylase (PAH) is defective in the inherited disorder phenylketonuria. PAH, a tetrameric enzyme, is highly regulated and displays positive cooperativity for its substrate, Phe. Whether Phe binds to an allosteric site is a matter of debate, despite several studies worldwide. To address this issue, we generated a dimeric model for Phe–PAH interactions, by performing molecular docking combined with molecular dynamics simulations on human and rat wild-type sequences and also on a human G46S mutant. Our results suggest that the allosteric Phe-binding site lies at the dimeric interface between the regulatory and the catalytic domains of two adjacent subunits. The structural and dynamical features of the site were characterized in depth and described. Interestingly, our findings provide evidence for lower allosteric Phe-binding ability of the G46S mutant than the human wild-type enzyme. This also explains the disease-causing nature of this mutant.     

The postnatal ontogeny of the sexually dimorphic vocal apparatus in goitred gazelles (Gazella subgutturosa)

This study quantitatively documents the progressive development of sexual dimorphism of the vocal organs along the ontogeny of the goitred gazelle (Gazella subgutturosa). The major, male‐specific secondary sexual features, of vocal anatomy in goitred gazelle are an enlarged larynx and a marked laryngeal descent. These features appear to have evolved by sexual selection and may serve as a model for similar events in male humans. Sexual dimorphism of larynx size and larynx position in adult goitred gazelles is more pronounced than in humans, whereas the vocal anatomy of neonate goitred gazelles does not differ between sexes. This study examines the vocal anatomy of 19 (11 male, 8 female) goitred gazelle specimens across three age‐classes, that is, neonates, subadults and mature adults. The postnatal ontogenetic development of the vocal organs up to their respective end states takes considerably longer in males than in females. Both sexes share the same features of vocal morphology but differences emerge in the course of ontogeny, ultimately resulting in the pronounced sexual dimorphism of the vocal apparatus in adults. The main differences comprise larynx size, vocal fold length, vocal tract length, and mobility of the larynx. The resilience of the thyrohyoid ligament and the pharynx, including the soft palate, and the length changes during contraction and relaxation of the extrinsic laryngeal muscles play a decisive role in the mobility of the larynx in both sexes but to substantially different degrees in adult females and males. Goitred gazelles are born with an undescended larynx and, therefore, larynx descent has to develop in the course of ontogeny. This might result from a trade‐off between natural selection and sexual selection requiring a temporal separation of different laryngeal functions at birth and shortly after from those later in life. J. Morphol. 277:826–844, 2016. © 2016 Wiley Periodicals, Inc.     

Habitat manipulation preferred by Eld’s Deer in Hainan Island,China

In order to improve the conservation status of the Eld’s Deer (Cervus eldii), a critically endangered species in China, a population in a nature reserve on Hainan Island was studied. Abundances and behaviours in two different habitat types, natural and manipulated, were recorded. We found that different habitats were preferred according to season. Both sexes were more abundant in the manipulated habitat from January to May, with males being more abundant in the natural habitat from September to October. However, females, were significantly more abundant from April and May in the manipulated habitat. The deer preferred the more open manipulated habitat for feeding, consistent with greater food availability. This study provides useful evidence for managers to create seasonally suitable habitat for the conservation of this species on Hainan Island. Similar methods could also be applied to other deer species in China, most of which are facing critical survival challenges.     

A study of nonrandom mating in a British population of the two-spot ladybird with a high frequency of the melanic morph

In some studies of the two-spot ladybird (Adalia bipunctata), melanic males have been found in excess over the typical morph in matings. Data suggest that a genetic female mating preference is responsible. The mating advantage of melanic males may be important in maintaining a polymorphism between melanic and typical ladybirds in many populations in the United Kingdom (U.K.). It has been reported that preference frequency varies linearly with melanic frequency throughout most of the U.K. One particular population ofAdalia bipunctata near Aberdare, South Wales, is noted for its high frequency of melanic individuals. It has been suggested that local environmental factors account for the high melanic frequency in this population. It is also possible, however, that a female mating preference may be at least partly responsible for the high frequency of melanics (as has been proposed for the rest of the U.K.). In this study, experiments have been performed to determine the level of female mating preference in the Aberdare population. No evidence was found for any mating advantage to melanic males. There was inconsistent and unexpected evidence that melanic females were overrepresented in matings, but the cause for this was unclear. Female mating preference does not appear, therefore, to be responsible for the high melanic frequency in the population ofAdalia bipunctata near Aberdare. There is not a simple association between mating preference and melanic frequency in U. K. populations of the two-spot ladybird.     

Honeybees establish specific sites on the comb for their waggle dances

Successful honeybee foragers perform dances on the surface of the comb where they interact with nectar receivers and dance followers. We have recorded the sites at which dances take place in large ten-frame hives and in two-frame observation hives. We find that dancing bees are most commonly found on particular combs in large hives and in particular areas on the combs in the observation hives. Although the site where dances take place may change from day to day, dancers will keep to the same site during the foraging period in any one day. Furthermore, if an established dance site is artificially relocated in the hive during the day, dancers seek these sites out before commencing their dances. We conclude that the dance sites are labelled in some way and so promote the congregation of both dancers and dance followers at the same site. Accepted: 27 November 1996