Probing the human antibody repertoire to exogenous antigens. Characterization of the H and L chain V region gene segments from anti-hepatitis B virus antibodies.

Structural studies of human antibody V regions have been largely limited to those involving the fetal repertoire, autoantibodies, and malignant cell rearrangements, leaving the "normal" repertoire relatively unexplored. In this study we describe the nucleotide sequences of the H and L chain V regions of four antibodies specific for the surface Ag of the hepatitis B virus. Monoclonal cell lines were derived from healthy individuals who received standard immunizations with the serum-derived or recombinant hepatitis B virus vaccines by fusion of PBL to a heterohybridoma cell line, SPAZ-4. We utilized the polymerase chain reaction to amplify the H and L chain V regions for cloning and sequencing. The four antibodies express the following V region combinations: VHIII/V lambda V, VHIII/V kappa II, VHIV/V kappa I, VHV/V lambda III. When compared to germline genes with the closest sequence homology, all of the V regions appear to have undergone somatic mutation, ranging from 3.4 to 11.3% for the H chain, and 5.1 to 9.2% for the L chain. Analysis of the mutations shows them to be typical for an Ag-driven immune response.     

Parasiticidal 2-alkoxy- and 2-aryloxyiminoalkyl trifluoromethanesulfonanilides

A series of novel 2-alkoxy- and 2-aryloxyiminoalkyl trifluoromethanesulfonanilide derivatives have shown significant in vitro parasiticidal activity against the ectoparasites Ctenocephalides felis and Rhipicephalus sanguineus. A number of these compounds also displayed significant in vitro endoparasite activity against the nematode Haemonchus contortus.     

Insecticidal effect of three diatomaceous earth formulations against adults of Sitophilus oryzae (Coleoptera: Curculionidae) and Tribolium confusum (Coleoptera: Tenebrionidae) on oat, rye, and triticale

Bioassays were conducted in the laboratory to assess the effect of the diatomaceous earth (DE) formulations Insecto, SilicoSec, and PyriSec, on stored oat, rye, and triticale, against adults of the rice weevil, Sitophilus oryzae (L.), and the confused flour beetle, Tribolium confusum Jacquelin du Val. The DEs were tested at three dose rates, 0.75, 1, and 1.5 g of DE/kg of grain. Adults of the two aforementioned species were exposed to all combinations of grain-formulation-dose rate, at 26 degrees C and 60% RH. Mortality in DE-treated commodities was recorded after 24 h, 48 h, 7 d, and 14 d of exposure for S. oryzae and T. confusum and after 21 d for T. confusum. In S. oryzae, adult mortality was almost 100% after 7 d of exposure in all three grains examined. The mortality of T. confusum adults in DE-treated grains did not reach 100%, even after 21 d of exposure. Generally, the application of DE in rye caused higher adult mortality of T. confusum than in the other two products. All three dose rates tested provided the same mortality level of S. oryzae adults after 7 d of exposure. In contrast, 1.5 g of DE resulted in significant higher adult mortality of T. confusum, in comparison with the other dose rates, even after 21 d of exposure. All formulations were equally effective after 7 d of exposure against S. oryzae, but at 48 h of exposure, PyriSec caused significantly higher mortality than the other two formulations. For both species, progeny production in the treated grains was significantly reduced in comparison with the untreated grains, whereas significant differences were noted among commodities, formulations, and dose rates. No progeny were recorded in the treated rye for either species or in the treated triticale for S. oryzae.     

Metabolomics to unveil and understand phenotypic diversity between pathogen populations

Leishmaniasis is a debilitating disease caused by the parasite Leishmania. There is extensive clinical polymorphism, including variable responsiveness to treatment. We study Leishmania donovani parasites isolated from visceral leishmaniasis patients in Nepal that responded differently to antimonial treatment due to differing intrinsic drug sensitivity of the parasites. Here, we present a proof-of-principle study in which we applied a metabolomics pipeline specifically developed for L. donovani to characterize the global metabolic differences between antimonial-sensitive and antimonial-resistant L. donovani isolates. Clones of drug-sensitive and drug-resistant parasite isolates from clinical samples were cultured in vitro and harvested for metabolomics analysis. The relative abundance of 340 metabolites was determined by ZIC-HILIC chromatography coupled to LTQ-Orbitrap mass spectrometry. Our measurements cover approximately 20% of the predicted core metabolome of Leishmania and additionally detected a large number of lipids. Drug-sensitive and drug-resistant parasites showed distinct metabolic profiles, and unsupervised clustering and principal component analysis clearly distinguished the two phenotypes. For 100 metabolites, the detected intensity differed more than three-fold between the 2 phenotypes. Many of these were in specific areas of lipid metabolism, suggesting that the membrane composition of the drug-resistant parasites is extensively modified. Untargeted metabolomics has been applied on clinical Leishmania isolates to uncover major metabolic differences between drug-sensitive and drug-resistant isolates. The identified major differences provide novel insights into the mechanisms involved in resistance to antimonial drugs, and facilitate investigations using targeted approaches to unravel the key changes mediating drug resistance.     

Redrawing the map of Great Britain from a network of human interactions

Do regional boundaries defined by governments respect the more natural ways that people interact across space? This paper proposes a novel, fine-grained approach to regional delineation, based on analyzing networks of billions of individual human transactions. Given a geographical area and some measure of the strength of links between its inhabitants, we show how to partition the area into smaller, non-overlapping regions while minimizing the disruption to each person''s links. We tested our method on the largest non-Internet human network, inferred from a large telecommunications database in Great Britain. Our partitioning algorithm yields geographically cohesive regions that correspond remarkably well with administrative regions, while unveiling unexpected spatial structures that had previously only been hypothesized in the literature. We also quantify the effects of partitioning, showing for instance that the effects of a possible secession of Wales from Great Britain would be twice as disruptive for the human network than that of Scotland.     

Parallel expression profiling of barley–stem rust interactions

The dominant barley stem rust resistance gene Rpg1 confers resistance to many but not all pathotypes of the stem rust fungus Puccinia graminis f. sp. tritici (Pgt). Transformation of Rpg1 into susceptible cultivar Golden Promise rendered the transgenic plants resistant to Pgt pathotype MCC but not to Pgt pathotype QCC. Our objective was to identify genes that are induced/repressed during the early stages of pathogen infection to elucidate the molecular mechanisms and role of Rpg1 in defense. A messenger ribonucleic acid expression analysis using the 22K Barley1 GeneChip was conducted in all pair-wise combinations of two isolines (cv. Golden Promise and Rpg1 transgenic line G02-448F-3R) and two Pgt pathotypes (MCC and QCC) across six time points. Analysis showed that a total of 34 probe sets exhibited expression pattern differences between Golden Promise (susceptible) and G02-448F-3R (resistant) infected with Pgt-MCC. A total of 14 probe sets exhibited expression pattern differences between Pgt-MCC (avirulent) and Pgt-QCC (virulent) inoculated onto G02-448F-3R. These differentially expressed genes were activated during the early infection process, before the hypersensitive response or fungal growth inhibition occurred. Our analysis provides a list of candidate signaling components, which can be analyzed for function in Rpg1-mediated disease resistance.