Recombinant renewable polyclonal antibodies

Only a small fraction of the antibodies in a traditional polyclonal antibody mixture recognize the target of interest, frequently resulting in undesirable polyreactivity. Here, we show that high-quality recombinant polyclonals, in which hundreds of different antibodies are all directed toward a target of interest, can be easily generated in vitro by combining phage and yeast display. We show that, unlike traditional polyclonals, which are limited resources, recombinant polyclonal antibodies can be amplified over one hundred million-fold without losing representation or functionality. Our protocol was tested on 9 different targets to demonstrate how the strategy allows the selective amplification of antibodies directed toward desirable target specific epitopes, such as those found in one protein but not a closely related one, and the elimination of antibodies recognizing common epitopes, without significant loss of diversity. These recombinant renewable polyclonal antibodies are usable in different assays, and can be generated in high throughput. This approach could potentially be used to develop highly specific recombinant renewable antibodies against all human gene products

Sub-inhibitory fosmidomycin exposures elicits oxidative stress in Salmonella enterica Serovar typhimurium LT2

Fosmidomycin is a time-dependent nanomolar inhibitor of methylerythritol phosphate (MEP) synthase, which is the enzyme that catalyzes the first committed step in the MEP pathway to isoprenoids. Importantly, fosmidomycin is one of only a few MEP pathway-specific inhibitors that exhibits antimicrobial activity. Most inhibitors identified to date only exhibit activity against isolated pathway enzymes. The MEP pathway is the sole route to isoprenoids in many bacteria, yet has no human homologs. The development of inhibitors of this pathway holds promise as novel antimicrobial agents. Similarly, analyses of the bacterial response toward MEP pathway inhibitors provides valuable information toward the understanding of how emergent resistance may ultimately develop to this class of antibiotics. We have examined the transcriptional response of Salmonella enterica serovar typhimurium LT2 to sub-inhibitory concentrations of fosmidomycin via cDNA microarray and RTPCR. Within the regulated genes identified by microarray were a number of genes encoding enzymes associated with the mediation of reactive oxygen species (ROS). Regulation of a panel of genes implicated in the response of cells to oxidative stress (including genes for catalases, superoxide dismutases, and alkylhydrogen peroxide reductases) was investigated and mild upregulation in some members was observed as a function of fosmidomycin exposure over time. The extent of regulation of these genes was similar to that observed for comparable exposures to kanamycin, but differed significantly from tetracycline. Furthermore, S. typhimurium exposed to sub-inhibitory concentrations of fosmidomycin displayed an increased sensitivity to exogenous H2O2 relative to either untreated controls or kanamycin-treated cells. Our results suggest that endogenous oxidative stress is one consequence of exposures to fosmidomycin, likely through the temporal depletion of intracellular isoprenoids themselves, rather than other mechanisms that have been proposed to facilitate ROS accumulation in bacteria (e.g. cell death processes or the ability of the antibiotic to redox cycle)

Cu-doped W18O49 nanowire reticular films for electrochromic supercapacitors

The method of improving the electrochromic properties of tungsten oxide by doping has attracted great interest. In this study, we successfully fabricated nanostructured tungsten oxide with different copper doping concentrations by a solvothermal method using copper chloride dihydrate and tungsten hexachloride as precursors. We found that the area-specific capacitance of the films gradually increased with the increase in doping concentration. The products were characterized by x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy, cyclic voltammetry, and chronoamperometry. The results show that the films we fabricated are reticular structures composed of nanowires. The doping of copper can improve the electron conductivity and shorten the ion transmission distance, thus improving energy storage properties. When the doping concentration is 7% and the annealing temperature is 200 °C, the film had the largest surface capacitance of 17.89 mF/cm2 and the capacitance retention reached 58.23%

A genome-wide scan to identify signatures of selection in Lueyang black -bone chicken

Lueyang black-bone chicken is a domestic breed in China. The genetic mechanism of the formation of important economic traits of this breed has not been studied systematically. Therefore, in this study, whole genome resequencing was used to systematically analyze and evaluate the genetic diversity of the black-feather and white-feather populations, and to screen and identify key genes related to phenotypes. The results of principal component analysis and population structure analysis showed that Lueyang black-feathered chickens and white-feathered chickens could be divided into 2 subgroups, and the genetic diversity of black-feathered chicken was richer than that of white-feathered chickens. Linkage disequilibrium analysis also showed that the selection intensity of black-feathered chickens was lower than for white-feathered chickens, which was mainly due to the small population size of white-feathered chickens and a certain degree of inbreeding. Fixation index (FST) analysis revealed that the candidate genes related to feather color traits were G-gamma, FA, FERM, Kelch, TGFb, Arf, FERM, and melanin synthesis-related gene tyrosinase (TYR). Based on Kyoto Encyclopedia of Genes and Genomes enrichment analysis, Jak-STAT, mTOR, and TGF-β signaling pathways were mainly related to melanogenesis and plume color. The findings of this study supported important information for the evaluation and protection of chicken genetic resources and help to analyze the unique genetic phenotypes such as melanin deposition and feather color of Lueyang black-bone chicken. Additionally, it could provide basic research data for the improvement and breeding of Lueyang black-bone chicken with characteristic traits

Emission factors of organic carbon and elemental carbon for residential coal and biomass fuels in China- A new database for 39 fuel-stove combinations

In recent years many households in northern China's rural areas tend to furnish their houses with water-circulating piping system for heating, which entails mini-boiler stoves to heat water via raw coal chunk or biomass pellets. In this study, consistent efforts were made to obtain first-hand emission factors of organic carbon (EFOC) and elemental carbon (EFEC) for residential solid fuel combustion. A total of 39 fuel/stove combinations, covering seven coals (with different geological maturities), eleven biomass fuels, and five different stoves, were tested. The mean EFOC and EFEC were (4.29 +/- 2.33) and (4.43 +/- 2.18) g/kg for residential coal combustion, (2.16 +/- 4.47) and (0.42 +/- 1.01) g/kg for indoor biomass burning. The EFs for tested coal combustion display a "bell shape" with the maximum EF value occurring at bitumite of middle maturity. Coal briquetting in this study led to a significant decrease in EFEC but a notable increase in EFOC, which contradicted with the result from some of previous studies that coal briquetting always leads to relatively low emissions of both OC and EC. The inside reason deserves further clarification. Averaging over the two mini-boiler stoves shows that the introduction of mini-boiler stoves can reduce 5% and 10% of OC from anthracite and bitumite, respectively, and 47% and 53% of EC from anthracite and bitumite, respectively, suggesting that transfer from pure heating stoves to mini-boiler stoves seems unlikely to increase carbonaceous particle emissions, particularly EC. The more significant decline in EFEC than in EFOC indicates that the access to mini-boiler stove for winter heating is very likely to be both a clean air measure and a warming mitigation approach. Updated emission inventories in China for the year of 2014 showed that the OC and EC emissions were 338 Gg and 529 Gg, respectively, from residential coal combustion, and 557 Gg and 79 Gg, respectively, from household biomass burning

Categories of regulated genes observed upon sub-inhibitory exposure to fosmidomycin.

<p>All assignments were made based on analysis of identified genes using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database (<a href="http://www.genome.jp/kegg/" target="_blank">www.genome.jp/kegg/</a>).</p

Cell viability of antibiotic challenged cells upon hydrogen peroxide exposure.

<p>Viable colony forming units/mL upon H₂O₂ (10 mM) treatment for untreated control cells, or cells previously challenged with fosmidomycin, kanamycin or tetracycline. The data represents the average of three independent tests and the error reflects the standard error of the mean.</p

Regulation of selected genes of relevance to oxidative stress identified in microarray analysis of short (20 min) sub-inhibitory exposures to fosmidomycin or kanamycin.

<p>Regulation of selected genes of relevance to oxidative stress identified in microarray analysis of short (20 min) sub-inhibitory exposures to fosmidomycin or kanamycin.</p

Potential Effects of Isoprenoid Deprivation on Cellular Respiration.

<p>Disruption of the MEP pathway reduces the cell’s ability to form late stage isoprenoid products such as ubiquinone and menaquinone. Impairment of bacterial respiration via inhibition of ubiquinone/menaquinone synthesis may decrease the cell’s ability to reduce oxygen into water, and ultimately may foster the production of reactive oxygen species through direct reduction of molecular oxygen.</p