Parochial altruism in humans

Social norms and the associated altruistic behaviours are decisive for the evolution of human cooperation and the maintenance of social order, and they affect family life, politics and economic interactions. However, as altruistic norm compliance and norm enforcement often emerge in the context of inter-group conflicts, they are likely to be shaped by parochialism--a preference for favouring the members of one's ethnic, racial or language group. We have conducted punishment experiments, which allow 'impartial' observers to punish norm violators, with indigenous groups in Papua New Guinea. Here we show that these experiments confirm the prediction of parochialism. We found that punishers protect ingroup victims--who suffer from a norm violation--much more than they do outgroup victims, regardless of the norm violator's group affiliation. Norm violators also expect that punishers will be lenient if the latter belong to their social group. As a consequence, norm violations occur more often if the punisher and the norm violator belong to the same group. Our results are puzzling for evolutionary multi-level selection theories based on selective group extinction as well as for theories of individual selection; they also indicate the need to explicitly examine the interactions between individuals stemming from different groups in evolutionary models.     

Proteome survey reveals modularity of the yeast cell machinery

Protein complexes are key molecular entities that integrate multiple gene products to perform cellular functions. Here we report the first genome-wide screen for complexes in an organism, budding yeast, using affinity purification and mass spectrometry. Through systematic tagging of open reading frames (ORFs), the majority of complexes were purified several times, suggesting screen saturation. The richness of the data set enabled a de novo characterization of the composition and organization of the cellular machinery. The ensemble of cellular proteins partitions into 491 complexes, of which 257 are novel, that differentially combine with additional attachment proteins or protein modules to enable a diversification of potential functions. Support for this modular organization of the proteome comes from integration with available data on expression, localization, function, evolutionary conservation, protein structure and binary interactions. This study provides the largest collection of physically determined eukaryotic cellular machines so far and a platform for biological data integration and modelling.     

SiC纤维（Nicalon）增强玻璃陶瓷的蠕变行为

考察了文题材料的蠕变行为，发现其以取决于所施加的应力与温度而出现的蠕变第一、第二、第三阶段为特征。蠕变过程中出现的主要结构变化为纤维重排、富碳界面层的氧化以及基质中晶体的生长。虽然复合材料的受力极限取决于残余玻璃相，但纤维的引入使得材料的热机械性能得以大幅度地提高。     

Two-dimensional geometry of spin excitations in the high-transition-temperature superconductor YBa2Cu3O6+x

The fundamental building block of the copper oxide superconductors is a Cu4O4 square plaquette. The plaquettes in most of these materials are slightly distorted to form a rectangular lattice, for which an influential theory predicts that high-transition-temperature (high-T(c)) superconductivity is nucleated in 'stripes' aligned along one of the axes. This theory received strong support from experiments that indicated a one-dimensional character for the magnetic excitations in the high-T(c) material YBa2Cu3O6.6 (ref. 4). Here we report neutron scattering data on 'untwinned' YBa2Cu3O6+x crystals, in which the orientation of the rectangular lattice is maintained throughout the entire volume. Contrary to the earlier claim, we demonstrate that the geometry of the magnetic fluctuations is two-dimensional. Rigid stripe arrays therefore appear to be ruled out over a wide range of doping levels in YBa2Cu3O6+x, but the data may be consistent with liquid-crystalline stripe order. The debate about stripes has therefore been reopened.     

Mutations in INVS encoding inversin cause nephronophthisis type 2, linking renal cystic disease to the function of primary cilia and left-right axis determination

Nephronophthisis (NPHP), an autosomal recessive cystic kidney disease, leads to chronic renal failure in children. The genes mutated in NPHP1 and NPHP4 have been identified, and a gene locus associated with infantile nephronophthisis (NPHP2) was mapped. The kidney phenotype of NPHP2 combines clinical features of NPHP and polycystic kidney disease (PKD). Here, we identify inversin (INVS) as the gene mutated in NPHP2 with and without situs inversus. We show molecular interaction of inversin with nephrocystin, the product of the gene mutated in NPHP1 and interaction of nephrocystin with beta-tubulin, a main component of primary cilia. We show that nephrocystin, inversin and beta-tubulin colocalize to primary cilia of renal tubular cells. Furthermore, we produce a PKD-like renal cystic phenotype and randomization of heart looping by knockdown of invs expression in zebrafish. The interaction and colocalization in cilia of inversin, nephrocystin and beta-tubulin connect pathogenetic aspects of NPHP to PKD, to primary cilia function and to left-right axis determination.     

Large-scale production of functional membrane proteins

The preparation of sufficient amounts of high-quality samples is still the major bottleneck for the characterization of membrane proteins by in vitro approaches. The hydrophobic nature, the requirement for complicated transport and modification pathways, and the often observed negative effects on membrane properties are intrinsic features of membrane proteins that frequently cause significant problems in overexpression studies. Establishing efficient protocols for the production of functionally folded membrane proteins is therefore a challenging task, and numerous specific characteristics have to be considered. In addition, a variety of expression systems have been developed, and choice of appropriate techniques could strongly depend on the desired target membrane proteins as well as on their intended applications. The production of membrane proteins is a highly dynamic field and new or modified approaches are frequently emerging. The review will give an overview of currently established processes for the production of functionally folded membrane proteins.     

Mutations in RNF135, a gene within the NF1 microdeletion region, cause phenotypic abnormalities including overgrowth

17q11 microdeletions that encompass NF1 cause 5%-10% of cases of neurofibromatosis type 1, and individuals with microdeletions are typically taller than individuals with intragenic NF1 mutations, suggesting that deletion of a neighboring gene might promote human growth. We identified mutations in RNF135, which is within the NF1 microdeletion region, in six families characterized by overgrowth, learning disability, dysmorphic features and variable additional features. These data identify RNF135 as causative of a new overgrowth syndrome and demonstrate that RNF135 haploinsufficiency contributes to the phenotype of NF1 microdeletion cases.     

Isolation of an autotrophic ammonia-oxidizing marine archaeon

For years, microbiologists characterized the Archaea as obligate extremophiles that thrive in environments too harsh for other organisms. The limited physiological diversity among cultivated Archaea suggested that these organisms were metabolically constrained to a few environmental niches. For instance, all Crenarchaeota that are currently cultivated are sulphur-metabolizing thermophiles. However, landmark studies using cultivation-independent methods uncovered vast numbers of Crenarchaeota in cold oxic ocean waters. Subsequent molecular surveys demonstrated the ubiquity of these low-temperature Crenarchaeota in aquatic and terrestrial environments. The numerical dominance of marine Crenarchaeota--estimated at 10(28) cells in the world's oceans--suggests that they have a major role in global biogeochemical cycles. Indeed, isotopic analyses of marine crenarchaeal lipids suggest that these planktonic Archaea fix inorganic carbon. Here we report the isolation of a marine crenarchaeote that grows chemolithoautotrophically by aerobically oxidizing ammonia to nitrite--the first observation of nitrification in the Archaea. The autotrophic metabolism of this isolate, and its close phylogenetic relationship to environmental marine crenarchaeal sequences, suggests that nitrifying marine Crenarchaeota may be important to global carbon and nitrogen cycles.