Improving the long‐term storage of a mammalian biosensor cell line via genetic engineering

The unique properties of mammalian cells make them valuable for a variety of applications in medicine, industry, and diagnostics. However, the utility of such cells is restricted due to the difficulty in storing them non‐frozen for an extended time and still maintaining their stability and responsiveness. In order to extend the active life span of a mammalian biosensor cell line at room and refrigerated temperatures, we have over expressed genes that are reported to provide protection from apoptosis, stress, or oxidation. We demonstrated that over expression of genes from the extremophile, Artemia franciscana, as well as GADD45β, extends room‐temperature storage of fully active cells 3.5‐fold, while over production of several anti‐apoptotic proteins extended 4°C storage 2‐ to 3‐fold. Methodologies like these that improve the stability of mammalian‐cell‐based technologies in the absence of freezers may enable widespread use of these tools in applications that have been considered impractical based solely on limited storage characteristics. Biotechnol. Bioeng. 2010; 106: 474–481. © 2010 Wiley Periodicals, Inc.     

Indoor Residual Spraying in Combination with Insecticide-Treated Nets Compared to Insecticide-Treated Nets Alone for Protection against Malaria: A Cluster Randomised Trial in Tanzania

Background

Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) of houses provide effective malaria transmission control. There is conflicting evidence about whether it is more beneficial to provide both interventions in combination. A cluster randomised controlled trial was conducted to investigate whether the combination provides added protection compared to ITNs alone.

Methods and Findings

In northwest Tanzania, 50 clusters (village areas) were randomly allocated to ITNs only or ITNs and IRS. Dwellings in the ITN+IRS arm were sprayed with two rounds of bendiocarb in 2012. Plasmodium falciparum prevalence rate (PfPR) in children 0.5–14 y old (primary outcome) and anaemia in children <5 y old (secondary outcome) were compared between study arms using three cross-sectional household surveys in 2012. Entomological inoculation rate (secondary outcome) was compared between study arms.IRS coverage was approximately 90%. ITN use ranged from 36% to 50%. In intention-to-treat analysis, mean PfPR was 13% in the ITN+IRS arm and 26% in the ITN only arm, odds ratio = 0.43 (95% CI 0.19–0.97, n = 13,146). The strongest effect was observed in the peak transmission season, 6 mo after the first IRS. Subgroup analysis showed that ITN users were additionally protected if their houses were sprayed. Mean monthly entomological inoculation rate was non-significantly lower in the ITN+IRS arm than in the ITN only arm, rate ratio = 0.17 (95% CI 0.03–1.08).

Conclusions

This is the first randomised trial to our knowledge that reports significant added protection from combining IRS and ITNs compared to ITNs alone. The effect is likely to be attributable to IRS providing added protection to ITN users as well as compensating for inadequate ITN use. Policy makers should consider deploying IRS in combination with ITNs to control transmission if local ITN strategies on their own are insufficiently effective. Given the uncertain generalisability of these findings, it would be prudent for malaria control programmes to evaluate the cost-effectiveness of deploying the combination.

Trial registration

www.ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01697852","term_id":"NCT01697852"}}NCT01697852 Please see later in the article for the Editors'' Summary     

Inhibition of sporulation, glycopeptide antibiotic production and resistance in Streptomyces toyocaensis NRRL 15009 by protein kinase inhibitors

Production of the glycopeptide antibiotic A47934 by Streptomyces toyocaensis NRRL 15009 begins in the late exponential phase in liquid culture and peaks in the early stationary phase. The pattern of cellular phosphoprotein production changes upon onset of A48934 production with the appearance of several novel phosphoproteins only when an antibiotic is being produced. Phosphoamino acid analysis revealed that S. toyocaensis NRRL 15009 produces proteins phosphorylated on His, Ser, Thr and Tyr, with most being membrane-associated. Addition of the isoflavones genistein or quercetin abolishes A47934 production in liquid culture and sporulation on solid medium. Furthermore, genistein slows the onset of inducible glycopeptide antibiotic resistance in S. toyocaensis NRRL 15009. These results support the participation of protein kinase pathways in A47934 biosynthesis and resistance and cell differentiation in S. toyocaensis NRRL 15009.     

Random coil chemical shifts in acidic 8 M urea: Implementation of random coil shift data in NMRView

Studies of proteins unfolded in acid or chemical denaturant can help in unraveling events during the earliest phases of protein folding. In order for meaningful comparisons to be made of residual structure in unfolded states, it is necessary to use random coil chemical shifts that are valid for the experimental system under study. We present a set of random coil chemical shifts obtained for model peptides under experimental conditions used in studies of denatured proteins. This new set, together with previously published data sets, has been incorporated into a software interface for NMRView, allowing selection of the random coil data set that fits the experimental conditions best.     

Density compensation in island avifaunas

Summary This paper analyzes factors which determine the extent of density compensation on islands; i.e., is the summed population density of all species on an island equal to the summed mainland density? A graphical analysis allows quantitative comparisons of density compensation studies. Two hypotheses which are generally applicable predict the extent of density compensation on islands: (1) Niche theory predicts that summed population densities should be low if island species number is low. (2) The habitat appropriateness hypothesis predicts that summed population densities should be low if island populations occupy unfamiliar habitat. Both hypotheses successfully explain variability in the extent of density compensation on islands. Relative to the mainland, summed population densities on islands are high when islands support a large number of species and those species occupy familiar habitats. Summed population densities on islands are low when islands support few species and those species occupy novel habitats.