Coordination Analysis Reveals Differences in Motor Strategies for the High Bar Longswing among Novice Adults

Coordination between arm-trunk and trunk-leg is important for effective longswing performance. This research describes inter-segmental coordination changes after a practice period of longswing on high bar in a novice cohort. Novices were divided by initial skill level (talent) into two groups: spontaneously-talented, (ST, n = 10, closer to expert performance) and non-spontaneously-talented (NST, n = 15). Additionally, post-practice longswing coordination was compared to expert gymnasts (n = 9). Longswing amplitude and coordination (inter-joint reversal points and continuous relative phase, CRP) were assessed for pre- and post-practice sessions. ANOVAs showed similar practice effects in swing enlargements for the ST (11%) and NST (18%), but inter-joint reversal points and positive area in CRP during the downswing were different. Due to practice, the ST group paired shoulder and hip reversal points (events) during the downswing closer and with larger velocity of the arm in relation to the trunk than the NST group. The NST failed to modify coordination probably due to a large variability at the beginning of the downswing. Given a similar amount of practice, talent could help to achieve the right temporal events’ sequence during downswing, which would allow the exploration of different segmental coordination. However, upswing coordination of the novice groups (ST and NST) requires more focused practice to achieve expert levels than downswing, especially the arm-trunk coordination.     

N-glycosylation Site Analysis Reveals Sex-related Differences in Protein N-glycosylation in the Rice Brown Planthopper (Nilaparvata lugens)

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Highlights

• •N-glycosylation site analysis of the hemipteran pest insect Nilaparvata lugens.
• •Differential N-glycosylation of proteins is observed between male and female adults.
• •Sex-specific glycoproteins are involved in insect reproduction.

     

Comprehensive Analysis of Silencing Mutants Reveals Complex Regulation of the Arabidopsis Methylome

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Highlights? Genome-wide single-nucleotide resolution methylation maps in 86 silencing mutants ? Complex interplays between different DNA methylation pathways ? Identification of novel regulators of DNA methylation     

Nuclear Genetic Diversity in Human Lice (Pediculus humanus) Reveals Continental Differences and High Inbreeding among Worldwide Populations

Understanding the evolution of parasites is important to both basic and applied evolutionary biology. Knowledge of the genetic structure of parasite populations is critical for our ability to predict how an infection can spread through a host population and for the design of effective control methods. However, very little is known about the genetic structure of most human parasites, including the human louse (Pediculus humanus). This species is composed of two ecotypes: the head louse (Pediculus humanus capitis De Geer), and the clothing (body) louse (Pediculus humanus humanus Linnaeus). Hundreds of millions of head louse infestations affect children every year, and this number is on the rise, in part because of increased resistance to insecticides. Clothing lice affect mostly homeless and refugee-camp populations and although they are less prevalent than head lice, the medical consequences are more severe because they vector deadly bacterial pathogens. In this study we present the first assessment of the genetic structure of human louse populations by analyzing the nuclear genetic variation at 15 newly developed microsatellite loci in 93 human lice from 11 sites in four world regions. Both ecotypes showed heterozygote deficits relative to Hardy–Weinberg equilibrium and high inbreeding values, an expected pattern given their parasitic life history. Bayesian clustering analyses assigned lice to four distinct genetic clusters that were geographically structured. The low levels of gene flow among louse populations suggested that the evolution of insecticide resistance in lice would most likely be affected by local selection pressures, underscoring the importance of tailoring control strategies to population-specific genetic makeup and evolutionary history. Our panel of microsatellite markers provides powerful data to investigate not only ecological and evolutionary processes in lice, but also those in their human hosts because of the long-term coevolutionary association between lice and humans.     

Genome-Wide Analysis Reveals Novel Regulators of Growth in Drosophila melanogaster

Organismal size depends on the interplay between genetic and environmental factors. Genome-wide association (GWA) analyses in humans have implied many genes in the control of height but suffer from the inability to control the environment. Genetic analyses in Drosophila have identified conserved signaling pathways controlling size; however, how these pathways control phenotypic diversity is unclear. We performed GWA of size traits using the Drosophila Genetic Reference Panel of inbred, sequenced lines. We find that the top associated variants differ between traits and sexes; do not map to canonical growth pathway genes, but can be linked to these by epistasis analysis; and are enriched for genes and putative enhancers. Performing GWA on well-studied developmental traits under controlled conditions expands our understanding of developmental processes underlying phenotypic diversity.     

Comparative Genomics of Gardnerella vaginalis Strains Reveals Substantial Differences in Metabolic and Virulence Potential

Background

Gardnerella vaginalis is described as a common vaginal bacterial species whose presence correlates strongly with bacterial vaginosis (BV). Here we report the genome sequencing and comparative analyses of three strains of G. vaginalis. Strains 317 (ATCC 14019) and 594 (ATCC 14018) were isolated from the vaginal tracts of women with symptomatic BV, while Strain 409-05 was isolated from a healthy, asymptomatic individual with a Nugent score of 9.

Principal Findings

Substantial genomic rearrangement and heterogeneity were observed that appeared to have resulted from both mobile elements and substantial lateral gene transfer. These genomic differences translated to differences in metabolic potential. All strains are equipped with significant virulence potential, including genes encoding the previously described vaginolysin, pili for cytoadhesion, EPS biosynthetic genes for biofilm formation, and antimicrobial resistance systems, We also observed systems promoting multi-drug and lantibiotic extrusion. All G. vaginalis strains possess a large number of genes that may enhance their ability to compete with and exclude other vaginal colonists. These include up to six toxin-antitoxin systems and up to nine additional antitoxins lacking cognate toxins, several of which are clustered within each genome. All strains encode bacteriocidal toxins, including two lysozyme-like toxins produced uniquely by strain 409-05. Interestingly, the BV isolates encode numerous proteins not found in strain 409-05 that likely increase their pathogenic potential. These include enzymes enabling mucin degradation, a trait previously described to strongly correlate with BV, although commonly attributed to non-G. vaginalis species.

Conclusions

Collectively, our results indicate that all three strains are able to thrive in vaginal environments, and therein the BV isolates are capable of occupying a niche that is unique from 409-05. Each strain has significant virulence potential, although genomic and metabolic differences, such as the ability to degrade mucin, indicate that the detection of G. vaginalis in the vaginal tract provides only partial information on the physiological potential of the organism.     

Mutational Analysis of the Integral Membrane Methyltransferase Isoprenylcysteine Carboxyl Methyltransferase (ICMT) Reveals Potential Substrate Binding Sites

The eukaryotic integral membrane enzyme isoprenylcysteine carboxyl methyltransferase (ICMT) methylates the carboxylate of a lipid-modified cysteine at the C terminus of its protein substrates. This is the final post-translational modification of proteins containing a CAAX motif, including the oncoprotein Ras, and therefore, ICMT may serve as a therapeutic target in cancer development. ICMT has no discernible sequence homology with soluble methyltransferases, and aspects of its catalytic mechanism are unknown. For example, how both the methyl donor S-adenosyl-l-methionine (AdoMet), which is water-soluble, and the methyl acceptor isoprenylcysteine, which is lipophilic, are recognized within the same active site is not clear. To identify regions of ICMT critical for activity, we combined scanning mutagenesis with methyltransferase assays. We mutated nearly half of the residues of the ortholog of human ICMT from Anopheles gambiae and observed reduced or undetectable catalytic activity for 62 of the mutants. The crystal structure of a distantly related prokaryotic methyltransferase (Ma Mtase), which has sequence similarity with ICMT in its AdoMet binding site but methylates different substrates, provides context for the mutational analysis. The data suggest that ICMT and Ma MTase bind AdoMet in a similar manner. With regard to residues potentially involved in isoprenylcysteine binding, we identified numerous amino acids within transmembrane regions of ICMT that dramatically reduced catalytic activity when mutated. Certain substitutions of these caused substrate inhibition by isoprenylcysteine, suggesting that they contribute to the isoprenylcysteine binding site. The data provide evidence that the active site of ICMT spans both cytosolic and membrane-embedded regions of the protein.     

Targeted De Novo Centromere Formation in Drosophila Reveals Plasticity and Maintenance Potential of CENP-A Chromatin

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Analysis of Polycerate Mutants Reveals the Evolutionary Co-option of HOXD1 for Horn Patterning in Bovidae

In the course of evolution, pecorans (i.e., higher ruminants) developed a remarkable diversity of osseous cranial appendages, collectively referred to as “headgear,” which likely share the same origin and genetic basis. However, the nature and function of the genetic determinants underlying their number and position remain elusive. Jacob and other rare populations of sheep and goats are characterized by polyceraty, the presence of more than two horns. Here, we characterize distinct POLYCERATE alleles in each species, both associated with defective HOXD1 function. We show that haploinsufficiency at this locus results in the splitting of horn bud primordia, likely following the abnormal extension of an initial morphogenetic field. These results highlight the key role played by this gene in headgear patterning and illustrate the evolutionary co-option of a gene involved in the early development of bilateria to properly fix the position and number of these distinctive organs of Bovidae.     

Variation among the dispersed (GATA)n sequences in Drosophila melanogaster

Five nonallelic copies of the dispersed (GATA)n repeated sequence of Drosophila melanogaster (referred to as GATA elements) have been sequenced and analysed. The GATA elements range in size from 111 to 444 bp, consisting predominantly of tandemly repeated GATAs, interspersed with variants of the subunit. The types and distributions of these variants are consistent with the hypothesis that they have arisen by a random accumulation of point mutations (substitutions, deletions, and insertions) in pure (GATA)n sequences. Duplications or deletions of the GATA subunit, and of GATA variants, have also probably occurred, as a result of either unequal crossing-over or slipped-strand mispairing. Evidence for duplication (deletion) has been obtained from a comparison of two allelic GATA elements isolated from different populations. GATA elements, in common with other dispersed, simple repeats, are probably highly variable in length.     

Differences in Crossover Frequency and Distribution among Three Sibling Species of Drosophila

Comparisons of the genetic and cytogenetic maps of three sibling species of Drosophila reveal marked differences in the frequency and cumulative distribution of crossovers during meiosis. The maps for two of these species, Drosophila melanogaster and D. simulans, have previously been described, while this report presents new map data for D. mauritiana, obtained using a set of P element markers. A genetic map covering nearly the entire genome was constructed by estimating the recombination fraction for each pair of adjacent inserts. The P-based genetic map of mauritiana is ~1.8 times longer than the standard melanogaster map. It appears that mauritiana has higher recombination along the entire length of each chromosome, but the difference is greatest in centromere-proximal regions of the autosomes. The mauritiana autosomes show little or no centromeric recombinational suppression, a characteristic that is prominent in melanogaster. D. simulans appears to be intermediate both in terms of total map length and intensity of the autosomal centromeric effect. These interspecific differences in recombination have important evolutionary implications for DNA sequence organization and variability. In particular, mauritiana is expected to differ from melanogaster in patterns and amounts of sequence variation and transposon insertions.