When Is Group Membership Zero-Sum? Effects of Ethnicity,Threat, and Social Identity on Dual National Identity

This paper presents an investigation into marginalizing racism, a form of prejudice whereby ingroup members claim that specific individuals belong to their group, but also exclude them by not granting them all of the privileges of a full ingroup member. One manifestation of this is that perceived degree of outgroup membership will covary negatively with degree of ingroup membership. That is, group membership may be treated as a zero-sum quantity (e.g., one cannot be both Australian and Iraqi). Study 1 demonstrated that judges allocate more zero-sum membership assignments and lower combined membership in their country of origin and their adopted country to high-threat migrants than low-threat migrants. Study 2 identified a subtle type of zero-sum reasoning which holds that stronger degree of membership in one’s original nationality constrains membership in a new nationality to a greater extent than stronger membership in the new nationality constrains membership in one’s original nationality. This pattern is quite general, being replicated in large samples from four nations (USA, UK, India, and China). Taken together, these studies suggest that marginalizing racism is more than a belief that people retain a “stain” from membership in their original group. Marginalizing racism also manifests itself as conditional zero-sum beliefs about multiple group memberships.     

In Vivo Interaction Proteomics Reveal a Novel p38 Mitogen-Activated Protein Kinase/Rack1 Pathway Regulating Proteostasis in Drosophila Muscle

Several recent studies suggest that systemic aging in metazoans is differentially affected by functional decline in specific tissues, such as skeletal muscle. In Drosophila, longevity appears to be tightly linked to myoproteostasis, and the formation of misfolded protein aggregates is a hallmark of senescence in aging muscle. Similarly, defective myoproteostasis is described as an important contributor to the pathology of several age-related degenerative muscle diseases in humans, e.g., inclusion body myositis. p38 mitogen-activated protein kinase (MAPK) plays a central role in a conserved signaling pathway activated by a variety of stressful stimuli. Aging p38 MAPK mutant flies display accelerated motor function decline, concomitant with an enhanced accumulation of detergent-insoluble protein aggregates in thoracic muscles. Chemical genetic experiments suggest that p38-mediated regulation of myoproteostasis is not limited to the control of reactive oxygen species production or the protein degradation pathways but also involves upstream turnover pathways, e.g., translation. Using affinity purification and mass spectrometry, we identified Rack1 as a novel substrate of p38 MAPK in aging muscle and showed that the genetic interaction between p38b and Rack1 controls muscle aggregate formation, locomotor function, and longevity. Biochemical analyses of Rack1 in aging and stressed muscle suggest a model whereby p38 MAPK signaling causes a redistribution of Rack1 between a ribosome-bound pool and a putative translational repressor complex.     

Variable segment number in centipedes: population genetics meets evolutionary developmental biology

The case studies of population genetics focus on intraspecific variation, but most cases--at least where the variation is polymorphic--deal with characters that are not directly linked to organismic structure or ontogeny. Conversely, the case studies of evolutionary developmental biology focus directly on structure/ontogeny, but usually involve only interspecific comparisons. To integrate these complementary approaches, it is desirable to have a model system that permits study of intraspecific variation in development, using a character whose genetic basis either is already known or can be elucidated. Segment number in geophilomorph centipedes is proposed as a possible model system of this kind. Segment number is variable in natural populations of geophilomorphs, while in the other centipede orders it is fixed, either completely (scutigeromorphs, lithobiomorphs), or at least within species (scolopendromorphs). Statistical analysis of data on the extent of variation in different geophilomorph species suggests that segment number may be of selective importance, rather than the variation being merely an inevitable consequence of the difficulty of achieving a high degree of repeatability when there is a large number of segments.     

Molecular identification and genetic diversity within species of the genera Hanseniaspora and Kloeckera

Three molecular methods, RAPD-PCR analysis, electrophoretic karyotyping and RFLP of the PCR-amplified ITS regions (ITS1, ITS2 and the intervening 5.8S rDNA), were studied for accurate identification of Hanseniaspora and Kloeckera species as well as for determining inter- and intraspecific relationships of 74 strains isolated from different sources and/or geographically distinct regions. Of these three methods, PCR-RFLP analysis of ITS regions with restriction enzymes DdeI and HinfI is proposed as a rapid identification method to discriminate unambiguously between all six Hanseniaspora species and the single non-ascospore-forming apiculate yeast species Kloeckera lindneri. Electrophoretic karyotyping produced chromosomal profiles by which the seven species could be divided into four groups sharing similar karyotypes. Although most of the 60 strains examined exhibited a common species-specific pattern, a different degree of chromosomal-length polymorphism and a variable number of chromosomal DNA fragments were observed within species. Cluster analysis of the combined RAPD-PCR fingerprints obtained with one 10-mer primer, two microsatellite primers and one minisatellite primer generated clusters which with a few exceptions are in agreement with the groups as earlier recognized in DNA-DNA homology studies.     

To manage or not? Successful native tree seedling restoration despite a dense,invasive shrub,Berberis thunbergii

Plant Ecology - Invasive plant species suppress native trees through a variety of mechanisms. A non-native shrub, Berberis thunbergii, has been shown to depress native tree seedling densities in...     

Genetic analysis of the raffinose oligosaccharide pathway in lentil seeds

Two lentil (Lens culinaris) cultivars, Syrian Local Large (SLL) and PANT-L-406 (PL), have been used to study the genetics of the raffinose family of oligosaccharides (RFO) and a related compound, ciceritol, which is a galactosyl cyclitol. The RFO and ciceritol are the major soluble -galactosides in lentil seeds. Crosses were made between the two lentil lines and the patterns of inheritance for the total -galactoside content and for individual RFO compounds (raffinose, stachyose, verbascose) and ciceritol were determined in the embryos and seed coats from single seeds of the reciprocal F1s, the F2s and ten F3 families. The inheritance patterns for each of the -galactosides were complex and much of this complexity was attributed to an interaction between the embryo and its surrounding testa. A clear-cut segregation pattern was observed for verbascose. This was the result of PL embryos having very low, or no, verbascose. The F2 embryos had a segregation ratio of 3 high to 1 low level for this compound, suggesting that within this cross a low verbascose content was determined by a single recessive gene. There was good evidence from the F2 and F3 generations of a negative correlation between low levels of verbascose and high levels of ciceritol, which suggests a metabolic link between the RFO pathway and the pathway leading to ciceritol. The data are discussed in terms of defining strategies for genetically manipulating the-galactoside composition in lentil seeds, such that their negative effects on nutrition may be overcome without reducing significantly their positive role in abiotic stress resistance.     

Evaluation of the catalytic specificity,biochemical properties,and milk clotting abilities of an aspartic peptidase from <Emphasis Type="Italic">Rhizomucor miehei</Emphasis>

In this study, we detail the specificity of an aspartic peptidase from Rhizomucor miehei and evaluate the effects of this peptidase on clotting milk using the peptide sequence of k-casein (Abz-LSFMAIQ-EDDnp) and milk powder. Molecular mass of the peptidase was estimated at 37 kDa, and optimum activity was achieved at pH 5.5 and 55 °C. The peptidase was stable at pH values ranging from 3 to 5 and temperatures of up 45 °C for 60 min. Dramatic reductions in proteolytic activity were observed with exposure to sodium dodecyl sulfate, and aluminum and copper (II) chloride. Peptidase was inhibited by pepstatin A, and mass spectrometry analysis identified four peptide fragments (TWSISYGDGSSASGILAK, ASNGGGGEYIFGGYDSTK, GSLTTVPIDNSR, and GWWGITVDRA), similar to rhizopuspepsin. The analysis of catalytic specificity showed that the coagulant activity of the peptidase was higher than the proteolytic activity and that there was a preference for aromatic, basic, and nonpolar amino acids, particularly methionine, with specific cleavage of the peptide bond between phenylalanine and methionine. Thus, this peptidase may function as an important alternative enzyme in milk clotting during the preparation of cheese.     

Fiber-type proportions in mammalian soleus muscle during postnatal development

We analyzed the fiber-type composition of the soleus muscle in rats and mice to determine whether the adult proportion of fiber types is fixed soon after birth or whether it changes during postnatal maturation. We examined muscles from animals varying in age from 1 week to 1 year using monoclonal antibodies that distinguish between fast and slow isoforms of myosin heavy chains. In cross sections of unfixed muscle containing profiles of all myofibers in the muscle, we counted the fibers that stained with antibodies to fast myosin, and in adjacent sections, those that stained positive with an antibody to slow myosin. We also counted the total number of fibers in each section. Rat soleus contained about 2500 myofibers, and mouse about 1000 at all ages studied, suggesting that myogenesis ceases in soleus by 1 week after birth or sooner. In mouse soleus, the relative proportions of fibers staining positive with fast and slow myosin antibodies were similar at all ages studied, about 60%–70% being fast and 30%–40% slow. In rat soleus, however, the proportions of fast antibody-positive and slow antibody-positive fibers changed dramatically during postnatal maturation. At 1 week after birth, about 50% of rat soleus fibers stained with fast myosin antibodies, whereas between 1 and 2 months this value fell to about 10%. In mouse, about 10% of fibers at 1 week, but none at 1 year, reacted with both fast and slow antibodies, whereas in rat, fewer than 3% bound both antibodies to a significant degree at 1 week. It is puzzling why, in rat soleus, the majority of apparently fast fibers present at 1 week is converted to a slow phenotype, whereas in mouse soleus the predominant change appears to be the suppression of fast myosin expression in a subset of fibers that expresses both myosin types at 1 week. It is possible that this may be related to differences in size and the amount of body growth between these two species.