The scholastic pendulum

The history of the physics of pendular motion rightly begins with Galileo's discovery of the isochronous character of that motion. There is, however, a ‘pre-history’ of the pendulum, centering on its initial recognition as a significant special case requiring explanation. This occurred in the writings of Jean Buridan and Nicole Oresme in the middle of the fourteenth century. Earlier works that might have been construed as discussing pendular motion are considered, as are the explanations for the scholastic ‘discovery’ of pendular motion put forth by Thomas Kuhn and Piero Ariotti. In contrast to these writers, this paper seeks to account for the pendulum's emergence with reference to an imaginary experiment concerning a body moving past the earth's center, medieval theories of impetus, and the proximate physical model of pendular motion, the late medieval heavy suspended church bell.     

Genome-wide association analysis identifies 20 loci that influence adult height

Adult height is a model polygenic trait, but there has been limited success in identifying the genes underlying its normal variation. To identify genetic variants influencing adult human height, we used genome-wide association data from 13,665 individuals and genotyped 39 variants in an additional 16,482 samples. We identified 20 variants associated with adult height (P < 5 x 10(-7), with 10 reaching P < 1 x 10(-10)). Combined, the 20 SNPs explain approximately 3% of height variation, with a approximately 5 cm difference between the 6.2% of people with 17 or fewer 'tall' alleles compared to the 5.5% with 27 or more 'tall' alleles. The loci we identified implicate genes in Hedgehog signaling (IHH, HHIP, PTCH1), extracellular matrix (EFEMP1, ADAMTSL3, ACAN) and cancer (CDK6, HMGA2, DLEU7) pathways, and provide new insights into human growth and developmental processes. Finally, our results provide insights into the genetic architecture of a classic quantitative trait.     

Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens

Under physiological conditions the gut-associated lymphoid tissues not only prevent the induction of a local inflammatory immune response, but also induce systemic tolerance to fed antigens. A notable exception is coeliac disease, where genetically susceptible individuals expressing human leukocyte antigen (HLA) HLA-DQ2 or HLA-DQ8 molecules develop inflammatory T-cell and antibody responses against dietary gluten, a protein present in wheat. The mechanisms underlying this dysregulated mucosal immune response to a soluble antigen have not been identified. Retinoic acid, a metabolite of vitamin A, has been shown to have a critical role in the induction of intestinal regulatory responses. Here we find in mice that in conjunction with IL-15, a cytokine greatly upregulated in the gut of coeliac disease patients, retinoic acid rapidly activates dendritic cells to induce JNK (also known as MAPK8) phosphorylation and release the proinflammatory cytokines IL-12p70 and IL-23. As a result, in a stressed intestinal environment, retinoic acid acted as an adjuvant that promoted rather than prevented inflammatory cellular and humoral responses to fed antigen. Altogether, these findings reveal an unexpected role for retinoic acid and IL-15 in the abrogation of tolerance to dietary antigens.     

Ascaris suum draft genome

Parasitic diseases have a devastating, long-term impact on human health, welfare and food production worldwide. More than two billion people are infected with geohelminths, including the roundworms Ascaris (common roundworm), Necator and Ancylostoma (hookworms), and Trichuris (whipworm), mainly in developing or impoverished nations of Asia, Africa and Latin America. In humans, the diseases caused by these parasites result in about 135,000 deaths annually, with a global burden comparable with that of malaria or tuberculosis in disability-adjusted life years. Ascaris alone infects around 1.2 billion people and, in children, causes nutritional deficiency, impaired physical and cognitive development and, in severe cases, death. Ascaris also causes major production losses in pigs owing to reduced growth, failure to thrive and mortality. The Ascaris-swine model makes it possible to study the parasite, its relationship with the host, and ascariasis at the molecular level. To enable such molecular studies, we report the 273 megabase draft genome of Ascaris suum and compare it with other nematode genomes. This genome has low repeat content (4.4%) and encodes about 18,500 protein-coding genes. Notably, the A. suum secretome (about 750 molecules) is rich in peptidases linked to the penetration and degradation of host tissues, and an assemblage of molecules likely to modulate or evade host immune responses. This genome provides a comprehensive resource to the scientific community and underpins the development of new and urgently needed interventions (drugs, vaccines and diagnostic tests) against ascariasis and other nematodiases.     

Exon shuffling by recombination between self-splicing introns of bacteriophage T4

The organization of genes into exons separated by introns may permit rapid evolution of protein-coding sequences by exon shuffling. Introns could provide non-coding targets for recombination, which would then give rise to novel combinations of exons. Evidence to support this theory is indirect and consists of examples of homologous domains of protein structure encoded in different genes, with introns in conserved positions at the boundaries of these domains. Here, we report the first direct evidence for exon shuffling. Two spontaneous deletion mutations of phage T4 have been characterized by sequencing, and they are clearly the result of recombination between homologous regions of two self-splicing group I introns. As a result of the recombination, exons of different genes are transcribed together, with a hybrid intron between them. One of these introns is proficient in self-splicing.     

Behaviour modification by in vitro mutagenesis of a variable region within the period gene of Drosophila

The period gene of Drosophila melanogaster, implicated in the control of both the circadian and male courtship song rhythms, is found to be polymorphic. Alleles differ in the length of a region of the gene encoding a series of threonine-glycine repeat units. The phenotypes of transformed fruit flies, in which the only functional period gene lacks the entire perfect threonine-glycine repeat region, show that the effects of the period gene on the circadian and male courtship song rhythms can be dissociated.     

Laboratory and field studies of the female sex pheromone of the olive moth,Prays oleae

Summary Analysis by GC-EAG indicates that abdominal tip extracts of femalePrays oleae contain a tetradecenal. Synthetic (Z)-7-tetradecenal elicits a strong EAG respones from maleP. oleae and field tests it to be comparable in attractancy with the virgin female moth. (Z)-9-Tetradecenal also produces a strong EAG response but it is not an attractant and, when added to (Z)-7-tetradecenal, markedly reduces trap catches.Acknowledgments. The authors are indebted to Mr N. Psylakis, Agricultural Research Centre, Chania, Crete, and to Dr D. Vassilopoulos, Benaki Phytopathological Institute, for providing facilities for this work. They thank the Commonwealth Institute of Entomology, London, for moth species confirmation.