Specific glycoprotein changes during development of the chick neural retina

After separation of whole proteins of chick neural retina by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS), a number of glycoproteins can be detected by staining the gels with 125I-labeled wheat germ agglutinin (WGA) and other lectins. The glycoprotein patterns show both quantitative and qualitative changes between days 7 and 13 of development. Some of these glycoproteins can be separated by chromatography on columns of insolubilized lectins. These observations suggest that purification of some of these glycoproteins identified by staining with radioactive lectins would yield retinal antigens which may be specific for developmental stage and cell type.     

Time series proteome profiling to study endoplasmic reticulum stress response

Time series profiling is a powerful approach for obtaining information on protein expression dynamics and prevailing biochemical pathways. To date, such information could only be obtained at the mRNA level using mature and highly parallel technologies such as microarray gene expression profiling. The generation of time series data at the protein level has lagged due to the lack of robust and highly reproducible methodologies. Using a combination of SILAC strategy, SDS-PAGE and LC-MS/MS, we demonstrate successful monitoring of expression levels of the same set of proteins across different time points within the ER compartment of human primary fibroblast cells when exposed to ER stress inducers tunicamycin and thapsigargin. Data visualization was facilitated using GeneSpring GX analysis platform that was designed to process Affymetrix microarray data. This software also facilitated the generation of important parameters such as data normalization, calculation of statistical values to extract significant changes in protein expression, and the cross comparison of data sets.     

Interplay between glutathione, Atx1 and copper: X-ray absorption spectroscopy determination of Cu(I) environment in an Atx1 dimer

X-ray absorption techniques have been used to characterise the primary coordination sphere of Cu(I) bound to glutathionate (GS⁻), to Atx1 and in Cu₂^I(GS⁻)₂(Atx1)₂, a complex recently proposed as the major form of Atx1 in the cytosol. In each complex, Cu(I) was shown to be triply coordinated. When only glutathione is provided, each Cu(I) is triply coordinated by sulphur atoms in the binuclear complex Cu^I ₂(GS⁻)₅, involving bridging and terminal thiolates. In the presence of Atx1 and excess of glutathione, under conditions where Cu^I ₂(GS⁻)₂(Atx1)₂ is formed, each Cu(I) is triply coordinated by sulphur atoms. Given these constraints, there are two different ways for Cu(I) to bridge the Atx1 dimer: either both Cu(I) ions contribute to bridging the dimer, or only one Cu(I) ion is responsible for bridging, the other one being coordinated to two glutathione molecules. These two models are discussed as regards Cu(I) transfer to Ccc2a.

Association of CAT polymorphisms with catalase activity and exposure to environmental oxidative stimuli

We tested the hypotheses that catalase activity is modified by CAT single nucleotide polymorphisms (SNPs) (-262;-844), and by their interactions with oxidant exposures (coal dusts, smoking), lymphotoxin alpha (LTA, NcoI) and tumor necrosis factor (TNF, -308) in 196 miners. Erythrocyte catalase, superoxide dismutase, and glutathione peroxidase activities were measured. The CAT -262 SNP was related to lower catalase activity (104, 87 and 72 k/g hemoglobin for CC, CT and TT, respectively, p < 0.0001). Regardless of CAT SNPs, the LTA NcoI but not the TNF-308 SNP was associated with catalase activity (p = 0.04 and p = 0.8). CAT -262 T carriers were less frequent in highly exposed miners (OR = 0.39 [0.20-0.78], p = 0.007). In CAT -262 T carriers only, catalase activity decreased with high dust exposure (p = 0.01). Haplotype analyses (combined CAT SNPs) confirm these results. Results show that CAT -262 and LTA NcoI SNPs, and interaction with coal dust exposure, influenced catalase activity.     

Cd2+- or Hg2+-binding proteins can replace the Cu+-chaperone Atx1 in delivering Cu+ to the secretory pathway in yeast

Copper delivery to Ccc2--the Golgi Cu+-ATPase--was investigated in vivo, replacing the Cu+-chaperone Atx1 by various structural homologues in an atx1-Delta yeast strain. Various proteins, displaying the same ferredoxin-like fold and (M/L)(T/S)CXXC metal-binding motif as Atx1 and known as Cu+-, Cd2+- or Hg2+-binding proteins were able to replace Atx1. Therefore, regardless of their original function, these proteins could all bind copper and transfer it to Ccc2, suggesting that Ccc2 is opportunistic and can interact with many different proteins to gain Cu+. The possible role of electrostatic potential surfaces in the docking of Ccc2 with these Atx1-homologues is discussed.     

Sows' Ears and Silver Linings. A Backward Look at Ethnography

Globalization, changing views of science, and alterations in the culture concept have gradually modified the way fieldwork is perceived within anthropology. This paper briefly examines the contributions of four ethnographers in order to argue that ethnography based on fieldwork remains essential to our definition as a profession. The claim is made here that unless anthropologists continue to make fieldwork central, anthropological theory will be cut off from its grounding in data. Other observers, less skilled than anthropologists but more daring, will increasingly supplant ethnographers in gathering new information that they then interpret and in claiming the public readership that anthropologists were once able successfully to address.