The condensin complexes play distinct roles to ensure normal chromosome morphogenesis during meiotic division in Arabidopsis

Meiosis is a specialized cell division essential for sexual reproduction. During meiosis the chromosomes are highly organized, and correct chromosome architecture is required for faithful segregation of chromosomes at anaphase I and II. Condensin is involved in chromosome organization during meiotic and mitotic cell divisions. Three condensin subunits, AtSMC4 and the condensin I and II specific subunits AtCAP-D2 and AtCAP-D3, respectively, have been studied for their role in meiosis. This has revealed that both the condensin I and condensin II complexes are required to maintain normal structural integrity of the meiotic chromosomes during the two nuclear divisions. Their roles appear functionally distinct in that condensin I is required to maintain normal compaction of the centromeric repeats and 45S rDNA, whereas loss of condensin II was associated with extensive interchromosome connections at metaphase I. Depletion of condensin is also associated with a slight reduction in crossover formation, suggesting a role during meiotic prophase I

The Papaver rhoeas S determinants confer self-incompatibility to Arabidopsis thaliana in planta

Distant relatives can share gene function The plants Arabidopsis thaliana and Papaver rhoeas (poppy) shared a common ancestor approximately 140 million years ago. Because of this evolutionary distance, although many of their genes share function, the mechanisms that allow these genes to function are expected to have diverged. However, Z. Lin et al. found that a pair of genes that prevent self-fertilization in poppy can confer the same trait when expressed in Arabidopsis. This incompatibility was much more like that of poppy than that of incompatible close relatives of Arabidopsis. Thus, similar long-distance transfer of incompatibility, a trait of interest for plant breeding, may be useful between other distantly related species. Science , this issue p. 684 </jats:p

Robot life: simulation and participation in the study of evolution and social behavior.

This paper explores the case of using robots to simulate evolution, in particular the case of Hamilton's Law. The uses of robots raises several questions that this paper seeks to address. The first concerns the role of the robots in biological research: do they simulate something (life, evolution, sociality) or do they participate in something? The second question concerns the physicality of the robots: what difference does embodiment make to the role of the robot in these experiments. Thirdly, how do life, embodiment and social behavior relate in contemporary biology and why is it possible for robots to illuminate this relation? These questions are provoked by a strange similarity that has not been noted before: between the problem of simulation in philosophy of science, and Deleuze's reading of Plato on the relationship of ideas, copies and simulacra

A genome-wide association scan of RR and QT interval duration in 3 European genetically isolated populations:the EUROSPAN project

We set out to identify common genetic determinants of the length of the RR and QT intervals in 2325 individuals from isolated European populations.We analyzed the heart rate at rest, measured as the RR interval, and the length of the corrected QT interval for association with 318 237 single-nucleotide polymorphisms. The RR interval was associated with common variants within GPR133, a G-protein-coupled receptor (rs885389, P=3.9 x 10(-8)). The QT interval was associated with the earlier reported NOS1AP gene (rs2880058, P=2.00 x 10(-10)) and with a region on chromosome 13 (rs2478333, P=4.34 x 10(-8)), which is 100 kb from the closest known transcript LOC730174 and has previously not been associated with the length of the QT interval.Our results suggested an association between the RR interval and GPR133 and confirmed an association between the QT interval and NOS1AP

Science and Ideology in Economic, Political, and Social Thought

This paper has two sources: One is my own research in three broad areas: business cycles, economic measurement and social choice. In all of these fields I attempted to apply the basic precepts of the scientific method as it is understood in the natural sciences. I found that my effort at using natural science methods in economics was met with little understanding and often considerable hostility. I found economics to be driven less by common sense and empirical evidence, then by various ideologies that exhibited either a political or a methodological bias, or both. This brings me to the second source: Several books have appeared recently that describe in historical terms the ideological forces that have shaped either the direct areas in which I worked, or a broader background. These books taught me that the ideological forces in the social sciences are even stronger than I imagined on the basis of my own experiences. The scientific method is the antipode to ideology. I feel that the scientific work that I have done on specific, long standing and fundamental problems in economics and political science have given me additional insights into the destructive role of ideology beyond the history of thought orientation of the works I will be discussing

BORA ON THE NORTHERN ADRIATIC, 12-18 APRIL 1982

Analysis is presented of a bora case on 12-18 April 1982, characterized by the longest bora duration in Senj (138 hours) during the ALPEX-SOP. The bora was observed only on the northern Adriatic. The vertical wind and stability profiles indicate that the part of the upstream inversion layer decoupled and descended toward the sea which is confirmed in the aircraft data analysis (Smith, 1987). The application of the generalized hydraulic theory on the continuously stratified atmosphere showed that the theory can successfully explain the bora phenomenon in the postfrontal bora situation

Chemical Evolution of Atmospheric Organic Carbon over Multiple Generations of Oxidation

The evolution of atmospheric organic carbon (OC) as it undergoes oxidation has a controlling influence on concentrations of key atmospheric species, including particulate matter, ozone, and oxidants. However, the full characterization of OC over hours to days of atmospheric processing has been stymied by its extreme chemical complexity. Here we study the multigenerational oxidation of -pinene in the laboratory, characterizing products with several state-of-the-art analytical techniques. While quantification of some early-generation products remains elusive, full carbon closure is achieved (within uncertainty) by the end of the experiments. This enables new insights into the effects of oxidation on OC properties (volatility, oxidation state, and reactivity), and the atmospheric lifecycle of OC. Following an initial period characterized by functionalization reactions and particle growth, fragmentation reactions dominate, forming smaller species. After approximately one day of atmospheric aging, most carbon is sequestered in two long-lived reservoirs, volatile oxidized gases and low-volatility particulate matter

Genetic Determinants of Circulating Sphingolipid Concentrations in European Populations

Sphingolipids have essential roles as structural components of cell membranes and in cell signalling, and disruption of their metabolism causes several diseases, with diverse neurological, psychiatric, and metabolic consequences. Increasingly, variants within a few of the genes that encode enzymes involved in sphingolipid metabolism are being associated with complex disease phenotypes. Direct experimental evidence supports a role of specific sphingolipid species in several common complex chronic disease processes including atherosclerotic plaque formation, myocardial infarction (MI), cardiomyopathy, pancreatic beta-cell failure, insulin resistance, and type 2 diabetes mellitus. Therefore, sphingolipids represent novel and important intermediate phenotypes for genetic analysis, yet little is known about the major genetic variants that influence their circulating levels in the general population. We performed a genome-wide association study (GWAS) between 318,237 single-nucleotide polymorphisms (SNPs) and levels of circulating sphingomyelin (SM), dihydrosphingomyelin (Dih-SM), ceramide (Cer), and glucosylceramide (GluCer) single lipid species (33 traits); and 43 matched metabolite ratios measured in 4,400 subjects from five diverse European populations. Associated variants (32) in five genomic regions were identified with genome-wide significant corrected p-values ranging down to 9.08 x 10(-66). The strongest associations were observed in or near 7 genes functionally involved in ceramide biosynthesis and trafficking: SPTLC3, LASS4, SGPP1, ATP10D, and FADS1-3. Variants in 3 loci (ATP10D, FADS3, and SPTLC3) associate with MI in a series of three German MI studies. An additional 70 variants across 23 candidate genes involved in sphingolipid-metabolizing pathways also demonstrate association (p = 10(-4) or less). Circulating concentrations of several key components in sphingolipid metabolism are thus under strong genetic control, and variants in these loci can be tested for a role in the development of common cardiovascular, metabolic, neurological, and psychiatric diseases