Toxicity of three acaricides to Tetranychus urticae (Tetranychidae: Acari) and Orius insidiosus (Anthocoridae: Hemiptera)

Management for twospotted spider mite, Tetranychus urticae Koch, populations in peanut, Arachis hypogaea L., relies on acaricides. The outcomes of acaricide applications are most predictable when complete information on their toxicity and specificity is available. Specifically, the degrees to which acaricides impact different stages of T. urticae and natural enemies combined determine the overall efficacy of an acaricide application. The objectives of this study were to determine stage-specific direct and residual efficacies of three acaricides (fenpropathrin, etoxazole, and propargite) against T. urticae, and the direct and residual toxicity of the acaricides to Orius insidiosus (Say) adults. Direct toxicity of acaricides to T. urticae was measured on peanut cuttings. All acaricide treatments caused significant mortality to a mixed stage population of T. urticae, and mortality did not differ among the acaricides 7 d after treatment. When toxicity to eggs was tested, the proportion of eggs that hatched for all acaricide treatments was significantly lower than the control, with etoxazole and propargite causing 100% mortality. Exposure to acaricide residues caused < 30% mortality of T. urticae adults 1 and 2 d after treatment and was not significantly different from the control. Fenpropathrin and propargite caused 100% mortality and etoxazole caused > 50% mortality of O. insidious adults after direct exposure to the acaricides. Residual toxicity of acaricides to O. insidiosus adults varied but remained toxic to O. insidiosus longer than to T. urticae. Fenpropathrin had the longest residual effect on O. insidiosus adults, causing > 95% mortality after 14 d; etoxazole and propargite caused < 30% mortality after 14 d.     

Salmonella spp., Vibrio spp., Clostridium perfringens, and Plesiomonas shigelloides in Marine and Freshwater Invertebrates from Coastal California Ecosystems

The coastal ecosystems of California are highly utilized by humans and animals, but the ecology of fecal bacteria at the land–sea interface is not well understood. This study evaluated the distribution of potentially pathogenic bacteria in invertebrates from linked marine, estuarine, and freshwater ecosystems in central California. A variety of filter-feeding clams, mussels, worms, and crab tissues were selectively cultured for Salmonella spp., Campylobacter spp., Escherichia coli-O157, Clostridium perfringens, Plesiomonas shigelloides, and Vibrio spp. A longitudinal study assessed environmental risk factors for detecting these bacterial species in sentinel mussel batches. Putative risk factors included mussel collection near higher risk areas for livestock or human sewage exposure, adjacent human population density, season, recent precipitation, water temperature, water type, bivalve type, and freshwater outflow exposure. Bacteria detected in invertebrates included Salmonella spp., C. perfringens, P. shigelloides, Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio alginolyticus. Overall, 80% of mussel batches were culture positive for at least one of the bacterial species, although the pathogens Campylobacter, E. coli-O157, and Salmonella were not detected. Many of the same bacterial species were also cultured from upstream estuarine and riverine invertebrates. Exposure to human sewage sources, recent precipitation, and water temperature were significant risk factors for bacterial detection in sentinel mussel batches. These findings are consistent with the hypothesis that filter-feeding invertebrates along the coast concentrate fecal bacteria flowing from land to sea and show that the relationships between anthropogenic effects on coastal ecosystems and the environmental niches of fecal bacteria are complex and dynamic.     

Impact of neonicotinoid seed treatments on thrips (Thysanoptera: Thripidae) and soybean yield in Virginia and North Carolina

Currently there are several neonicotinoid insecticide seed treatments registered for use on soybean (Glycine max L.), with disparity in adoption rates in the eastern United States. A complex of seedling insect pests is found in mid-south soybean, but thrips are the primary early season pest of soybean in Virginia and North Carolina. Published knowledge regarding their impact on soybean yield is minimal, as is the impact of thrips on soybean yield; thrips species composition is also understudied. In 2008 through 2010, nine field experiments in Virginia and North Carolina were conducted to evaluate the impact on thrips population dynamics; the influence on yield of neonicotinoid seed treatments, imidacloprid and thiamethoxam, was reported from nine of these experiments. Moreover, thrips species abundance was recorded in three of these experiments. Both imidacloprid and thiamethoxam reduced thrips densities compared with untreated soybean. Thiamethoxam was more effective than imidacloprid in reducing adult thrips densities at 5 wk after planting. Adult densities peaked at 3 wk after planting, followed by larval densities, which peaked at 4 wk after planting. The most abundant thrips species was Frankliniella fusca (Hinds), followed by Neohydatothrips variabilis (Beach). Other common species included F. occidentalis (Pergande) and F. tritici (Fitch). In general, F. fusca was more common earlier in the season, while N. variabilis was more common later in the season. There were no significant differences in yield among any of the treatments or in the untreated controls. Although neonicotinoid insecticides reduced thrips abundance, data collected in these studies demonstrated that there was no positive yield response.     

Elevated levels of fibrinogen-derived endogenous citrullinated peptides in synovial fluid of rheumatoid arthritis patients

Introduction

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation of the joints and the presence of autoantibodies directed against proteins containing the non-standard arginine-derived amino acid citrulline. The protein fibrinogen, which has an essential role in blood clotting, is one of the most prominent citrullinated autoantigens in RA, particularly because it can be found in the inflamed tissue of affected joints. Here, we set out to analyze the presence of citrullinated endogenous peptides in the synovial fluid of RA and arthritic control patients.

Methods

Endogenous peptides were isolated from the synovial fluid of RA patients and controls by filtration and solid phase extraction. The peptides were identified and quantified using high-resolution liquid chromatography-mass spectrometry.

Results

Our data reveal that the synovial fluid of RA patients contains soluble endogenous peptides, derived from fibrinogen, containing significant amounts of citrulline residues and, in some cases, also phosphorylated serine. Several citrullinated peptides are found to be more abundantly present in the synovial fluid of RA patients compared to patients suffering from other inflammatory diseases affecting the joints.

Conclusions

The increased presence of citrullinated peptides in RA patients points toward a possible specific role of these peptides in the immune response at the basis of the recognition of citrullinated peptides and proteins by RA patient autoantibodies.     

A Characterization of the Oral Microbiome in Allogeneic Stem Cell Transplant Patients

Background

The mouth is a complex biological structure inhabited by diverse bacterial communities. The purpose of this study is to describe the effects of allogeneic stem cell transplantation on the oral microbiota and to examine differences among those patients who acquired respiratory complications after transplantation.

Methodology/Principal Findings

All patients were consented at the National Institutes of Health, Clinical Center. Bacterial DNA was analyzed from patients'' oral specimens using the Human Oral Microbe Identification Microarray. The specimens were collected from four oral sites in 45 allogeneic transplantation patients. Specimens were collected at baseline prior to transplantation, after transplantation at the nadir of the neutrophil count and after myeloid engraftment. If respiratory signs and symptoms developed, additional specimens were obtained. Patients were followed for 100 days post transplantation. Eleven patients'' specimens were subjected to further statistical analysis. Many common bacterial genera, such as Streptococcus, Veillonella, Gemella, Granulicatella and Camplyobacter were identified as being present before and after transplantation. Five of 11 patients developed respiratory complications following transplantation and there was preliminary evidence that the oral microbiome changed in their oral specimens. Cluster analysis and principal component analysis revealed this change in the oral microbiota.

Conclusions/Significance

After allogeneic transplantation, the oral bacterial community''s response to a new immune system was not apparent and many of the most common core oral taxa remained unaffected. However, the oral microbiome was affected in patients who developed respiratory signs and symptoms after transplantation. The association related to the change in the oral microbiota and respiratory complications after transplantation will be validated by future studies using high throughput molecular methods.     

1H, 15N, and 13C Chemical shift assignments of the navel orange worm pheromone-binding protein-1 (Atra-PBP1)

A pheromone-binding protein from navel orange worm, Amyelois transitella (Atra-PBP1) binds to non-polar pheromone molecules and facilitates the transport and delivery of pheromone to the membrane-bound pheromone receptors. We report complete NMR chemical shift assignments of Atra-PBP1 obtained at pH 4.5 and 25°C (BMRB No. 15601).     

Structural insights into membrane targeting by the flagellar calcium-binding protein (FCaBP), a myristoylated and palmitoylated calcium sensor in Trypanosoma cruzi

The flagellar calcium-binding protein (FCaBP) of the protozoan Trypanosoma cruzi is targeted to the flagellar membrane where it regulates flagellar function and assembly. As a first step toward understanding the Ca(2+)-induced conformational changes important for membrane-targeting, we report here the x-ray crystal structure of FCaBP in the Ca(2+)-free state determined at 2.2A resolution. The first 17 residues from the N terminus appear unstructured and solvent-exposed. Residues implicated in membrane targeting (Lys-19, Lys-22, and Lys-25) are flanked by an exposed N-terminal helix (residues 26-37), forming a patch of positive charge on the protein surface that may interact electrostatically with flagellar membrane targets. The four EF-hands in FCaBP each adopt a "closed conformation" similar to that seen in Ca(2+)-free calmodulin. The overall fold of FCaBP is closest to that of grancalcin and other members of the penta EF-hand superfamily. Unlike the dimeric penta EF-hand proteins, FCaBP lacks a fifth EF-hand and is monomeric. The unstructured N-terminal region of FCaBP suggests that its covalently attached myristoyl group at the N terminus may be solvent-exposed, in contrast to the highly sequestered myristoyl group seen in recoverin and GCAP1. NMR analysis demonstrates that the myristoyl group attached to FCaBP is indeed solvent-exposed in both the Ca(2+)-free and Ca(2+)-bound states, and myristoylation has no effect on protein structure and folding stability. We propose that exposed acyl groups at the N terminus may anchor FCaBP to the flagellar membrane and that Ca(2+)-induced conformational changes may control its binding to membrane-bound protein targets.