Identifying permethrin resistance loci in malaria vectors by genetic mapping

Identification of the major loci responsible for insecticide resistance in malaria vectors would aid the development andimplementation of effective resistance management strategies, which are urgently needed to tackle the growing threat posedby resistance to the limited insecticides available for malaria control. Genome-wide association studies in the major malariavector, Anopheles gambiae, have been hindered by the high degree of within-population structuring and very low levels oflinkage disequilibrium hence we revisited the use of quantitative trait loci (QTL) mapping to study resistance phenotypesin this vector species. Earlier work, identified two major QTL associated with pyrethroid resistance in A. gambiae s.s. fromEast Africa using genetic crossing of laboratory-colonized resistant and susceptible strains. In this study, we report theresults from genetic mapping of pyrethroid resistance in three isofemale pedigrees established from wild-caught femaleA. gambiae s.s. mosquitoes from Benin. We identified two QTL on chromosomes 2L and 3R in these field populations, insimilar genomic locations to theQTLidentified in laboratory strains. The relative merits of two alternative study designs arediscussed and suggestions made for future genetic mapping studies of insecticide resistance in mosquitoes

Nitrate reducing commensal bacterium stimulates germination through nitric oxide production-a hypothesis [abstract]

Abstract only availableThe pink-pigmented (PPFM) commensal bacterium bacterium, Methylobacterium extorquens AM1, stimulates germination of soybean and other plants. I am testing the hypothesis that germination is stimulated by bacterial-produced nitric oxide (NO). A potential source of NO is nitrate reductase (NR) action on nitrite. Our goal was to identify NR gene(s), disrupt it(them) and examine germination stimulation of the mutants. Two nitrate reductase (NR) sequences were identified in the M. extorquens genome. Primers were designed and used to amplify both full-length and internal fragments of each NR gene. The internal fragments were cloned into a suicide vector (pAYC61) which encodes PPFM-expressed resistance gene to tetracycline (tetR). Tri-parental mating was then used to introduce pAYC61, carrying the internal NR sequences, into the PPFM strain, and tet-resistant PPFM colonies were selected. Methanol was used as the sole carbon source, thus selecting against the E. coli partners in the mating. A screen was devised to test among the tet-resistant progeny "exconjugates" for those with homologous integration of the internal NR sequence integrated into the respective host PPFM NR gene. Such integration will create two non-functional incomplete copies of the host NR gene. The screen will be based on PCR whereby primers will match vector sequence with NR sequence that is NOT part of the internal fragment. Once each NR gene is confirmed to be interrupted, the mutants will be tested for their ability to reduce nitrate to an utilizable nitrogen source. Germination stimulation and seedling root development will be examined by imbibing seed with progenitor and NR- PPFMs. The experiment will confirm or refute our observations of increased germination and lateral root formation in plants with PPFMs. Further, it will indicate whether such effects are due to nitric oxide produced by bacterial NR action on nitrate. Controls will be bacterium grown with without nitrate and seedlings grown with external NO sources and with an NO trap.MU Monsanto Undergraduate Research Fellowshi

What do pink pigs and soybeans have in common? Selecting for mutants in the ureide pathway

Abstract only availablePink Pigmented Facultative Methylotrophic bacteria (PPFMs) have been found to be the most abundant microorganisms among phylloplane microflora, and have been recovered from all plants examined. PPFMs are seed-transmitted and have been shown to enhance germination. PPFMs may contribute nitrogen, which is an essential nutrient, to the plant. In an attempt to determine this and gain a better understanding of the genes involved in ureide (allantoin, allantoate, etc,) utilization in PPFMs, we tried to ellicit mutants along the pathway. We performed a bi-parental mating between the PPFM soybean isolate (wild-type) and an E. coli strain containing a plasmid for a kanamycin resistance. This antibiotic resistance plasmid was randomly inserted into the PPFM's genome. The goal is to select mutants that lose the ability to break down ureides. Selection on different media is used to isolate the different mutants along the pathway. Seed surface sterilization does not remove PPFMs since they are found below the seed coat. We have devised a method to eliminate the bacteria by heating the seeds at 50°C for 48 hours. This treatment does not damage the seed. Heat-treated and un-heated soybean seeds were inoculated with a kanamycin resistant soybean isolate strain of PPFM (B140). These plants were grown to maturity in the greenhouse and seeds were collected. We germinated this second generation of seed and are looking to recover kanamycin resistant PPFM bacteria both from the seed as well as the first unifoliate leaves of the soybean. We were able to isolate several putative PPFM ureide utilization mutants. This research will give insight into the interactions between PPFMs and soybean that may be applied to many other plants. Experiments to recover kanamycin resistant bacteria from the seed and from the first unifoliate leaves of the plants are in progress.MU Monsanto Undergraduate Research Fellowshi

Measurement of Direct Photon Emission in K^+ -> pi^+ pi^0 gamma Decay

We have performed a measurement of the K^+ -> pi^+ pi^0 gamma decay and have observed 2 X 10^4 events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of (4.7\pm0.8\pm0.3) X 10^{-6} in the pi^+ kinetic energy region of 55 to 90 MeV and requires no component due to interference with inner bremsstrahlung.Comment: 9 pages, 3 figures. To be submitted to PR

Search for the decay K+→π+ννˉK^+\to \pi^+ \nu \bar\nu in the momentum region Pπ<195 MeV/cP_\pi < 195 {\rm ~MeV/c}

We have searched for the decay $K^+ \to \pi^+ \nu \bar\nu$ in the kinematic region with pion momentum below the $K^+ \to \pi^+ \pi^0$ peak. One event was observed, consistent with the background estimate of $0.73\pm 0.18$. This implies an upper limit on $B(K^+ \to \pi^+ \nu \bar\nu)< 4.2\times 10^{-9}$ (90% C.L.), consistent with the recently measured branching ratio of $(1.57^{+1.75}_{-0.82}) \times 10^{-10}$, obtained using the standard model spectrum and the kinematic region above the $K^+ \to \pi^+ \pi^0$ peak. The same data were used to search for $K^+ \to \pi^+ X^0$, where $X^0$ is a weakly interacting neutral particle or system of particles with $150 < M_{X^0} < 250 {\rm ~MeV/c^2}$.Comment: 4 pages, 2 figure

Poly(ADP-ribose) polymerase family member 14 (PARP14) is a novel effector of the JNK2-dependent pro-survival signal in multiple myeloma

Copyright @ 2013 Macmillan Publishers Limited. This is the author's accepted manuscript. The final published article is available from the link below.Regulation of cell survival is a key part of the pathogenesis of multiple myeloma (MM). Jun N-terminal kinase (JNK) signaling has been implicated in MM pathogenesis, but its function is unclear. To elucidate the role of JNK in MM, we evaluated the specific functions of the two major JNK proteins, JNK1 and JNK2. We show here that JNK2 is constitutively activated in a panel of MM cell lines and primary tumors. Using loss-of-function studies, we demonstrate that JNK2 is required for the survival of myeloma cells and constitutively suppresses JNK1-mediated apoptosis by affecting expression of poly(ADP-ribose) polymerase (PARP)14, a key regulator of B-cell survival. Strikingly, we found that PARP14 is highly expressed in myeloma plasma cells and associated with disease progression and poor survival. Overexpression of PARP14 completely rescued myeloma cells from apoptosis induced by JNK2 knockdown, indicating that PARP14 is critically involved in JNK2-dependent survival. Mechanistically, PARP14 was found to promote the survival of myeloma cells by binding and inhibiting JNK1. Moreover, inhibition of PARP14 enhances the sensitization of MM cells to anti-myeloma agents. Our findings reveal a novel regulatory pathway in myeloma cells through which JNK2 signals cell survival via PARP14, and identify PARP14 as a potential therapeutic target in myeloma.Kay Kendall Leukemia Fund, NIH, Cancer Research UK, Italian Association for Cancer Research and the Foundation for Liver Research

A Status Report on Conflict Analysis in Mixed Integer Nonlinear Programming

Mixed integer nonlinear programs (MINLPs) are arguably among the hardest optimization problems, with a wide range of applications. MINLP solvers that are based on linear relaxations and spatial branching work similar as mixed integer programming (MIP) solvers in the sense that they are based on a branch-and-cut algorithm, enhanced by various heuristics, domain propagation, and presolving techniques. However, the analysis of infeasible subproblems, which is an important component of most major MIP solvers, has been hardly studied in the context of MINLPs. There are two main approaches for infeasibility analysis in MIP solvers: conflict graph analysis, which originates from artificial intelligence and constraint programming, and dual ray analysis. The main contribution of this short paper is twofold. Firstly, we present the first computational study regarding the impact of dual ray analysis on convex and nonconvex MINLPs. In that context, we introduce a modified generation of infeasibility proofs that incorporates linearization cuts that are only locally valid. Secondly, we describe an extension of conflict analysis that works directly with the nonlinear relaxation of convex MINLPs instead of considering a linear relaxation. This is work-in-progress, and this short paper is meant to present first theoretical considerations without a computational study for that part

Malaria reemergence in the Peruvian Amazon region.

Epidemic malaria has rapidly emerged in Loreto Department, in the Peruvian Amazon region. Peru reports the second highest number of malaria cases in South America (after Brazil), most from Loreto. From 1992 to 1997, malaria increased 50-fold in Loreto but only fourfold in Peru. Plasmodium falciparum infection, which has increased at a faster rate than P. vivax infection in the last 3 years, became the dominant Plasmodium infection in the highest transmission areas in the 1997 rainy season. The vector Anopheles darlingi has also increased during this epidemic in Loreto. Moreover, chloroquine and pyrimethamine-sulfadoxine drug-resistant P. falciparum strains have emerged, which require development of efficacious focal drug treatment schemes

Further Evidence for the Decay K+ to pi+ neutrino-antineutrino

Additional evidence for the rare kaon decay K+ to pi+ neutrino-antineutrino has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211<P<229 MeV/c, bringing the total for the combined data set to two. Including all data taken, the backgrounds were estimated to contribute 0.15 pm 0.05 events. The branching ratio is B=1.57^{+1.75}_{-0.82} 10^{-10}.Comment: 10 pages, 2 figure