Acetylcholinesterase mediated susceptibility of soldiers and workers of formosan subterranean termite (Isoptera: Rhinotermitidae) to chlorpyrifos

Target site studies were undertaken to examine the difference in susceptibility of Formosan subterranean termite, Coptotermes formosanus Shiraki, workers and soldiers to chlorpyrifos. Workers exhibited significantly greater acetylcholinesterase activity per insect than soldiers (118.63 +/- 48.51 versus 47.98 +/- 22.59 mOD/min/insect equivalent). Likewise, enzyme activity (mean +/- SD) per milligram of protein was greater in workers than soldiers (440.30 +/- 267.43 versus 311.53 +/- 149.83 mOD/min/mg protein). The enzyme of soldiers was more sensitive to the acetylcholinesterase (AChE) inhibitors eserine and chlorpyrifos-oxon than that of workers. The I50s of chlorpyrifos-oxon were 2.66 and 4.59 nM for soldiers and workers, respectively, whereas the I50s of eserine were 16.56 and 25.41 nM for soldiers and workers, respectively. The amount of protein was significantly higher in workers than in soldiers with mean values of 0.270 +/- 0.102 and 0.154 +/- 0.054 mg/insect equivalent, respectively. We suggest that the differential response of workers and soldiers to chlorpyrifos may be due to the difference in AChE sensitivity to inhibition and the amount of protein between them.     

Intake of Farmed Atlantic Salmon Fed Soybean Oil Increases Insulin Resistance and Hepatic Lipid Accumulation in Mice

Background

To ensure sustainable aquaculture, fish derived raw materials are replaced by vegetable ingredients. Fatty acid composition and contaminant status of farmed Atlantic salmon (Salmo salar L.) are affected by the use of plant ingredients and a spillover effect on consumers is thus expected. Here we aimed to compare the effects of intake of Atlantic salmon fed fish oil (FO) with intake of Atlantic salmon fed a high proportion of vegetable oils (VOs) on development of insulin resistance and obesity in mice.

Methodology/principal findings

Atlantic salmon were fed diets where FO was partly (80%) replaced with three different VOs; rapeseed oil (RO), olive oil (OO) or soy bean oil (SO). Fillets from Atlantic salmon were subsequently used to prepare Western diets (WD) for a mouse feeding trial. Partial replacement of FO with VOs reduced the levels of polychlorinated biphenyls (PCB) and dichloro-diphenyl-tricloroethanes (DDT) with more than 50% in salmon fillets, in WDs containing the fillets, and in white adipose tissue from mice consuming the WDs. Replacement with VOs, SO in particular, lowered the n−3 polyunsaturated fatty acid (PUFA) content and increased n−6 PUFA levels in the salmon fillets, in the prepared WDs, and in red blood cells collected from mice consuming the WDs. Replacing FO with VO did not influence obesity development in the mice, but replacement of FO with RO improved glucose tolerance. Compared with WD-FO fed mice, feeding mice WD-SO containing lower PCB and DDT levels but high levels of linoleic acid (LA), exaggerated insulin resistance and increased accumulation of fat in the liver.

Conclusion/Significance

Replacement of FO with VOs in aqua feed for farmed salmon had markedly different spillover effects on metabolism in mice. Our results suggest that the content of LA in VOs may be a matter of concern that warrants further investigation.     

Semiparametric models for missing covariate and response data in regression models

We consider a class of semiparametric models for the covariate distribution and missing data mechanism for missing covariate and/or response data for general classes of regression models including generalized linear models and generalized linear mixed models. Ignorable and nonignorable missing covariate and/or response data are considered. The proposed semiparametric model can be viewed as a sensitivity analysis for model misspecification of the missing covariate distribution and/or missing data mechanism. The semiparametric model consists of a generalized additive model (GAM) for the covariate distribution and/or missing data mechanism. Penalized regression splines are used to express the GAMs as a generalized linear mixed effects model, in which the variance of the corresponding random effects provides an intuitive index for choosing between the semiparametric and parametric model. Maximum likelihood estimates are then obtained via the EM algorithm. Simulations are given to demonstrate the methodology, and a real data set from a melanoma cancer clinical trial is analyzed using the proposed methods.     

Amino acid sequences of stomach and nonstomach lysozymes of ruminants

Summary Complete amino acid sequences are presented for lysozymesc from camel and goat stomachs and compared to sequences of other lysozymesc. Tree analysis suggests that the rate of amino acid replacement went up as soon as lysozyme was recruited for the stomach function in early ruminants. The two lysozymes from goat stomach are the products of a gene duplication that probably took place before the divergence of cow, goat, and deer about 25 million years ago. Partial sequences of three lysozymes from goat tears indicated that (a) the goat tear family of lysozymes may have diverged from the stomach lysozyme family by an ancient duplication and (b) later duplications are probably responsible for the multiple forms of tear and milk lysozymes in ruminants.     

Mutations in RIPK4 cause the autosomal-recessive form of popliteal pterygium syndrome

The autosomal-recessive form of popliteal pterygium syndrome, also known as Bartsocas-Papas syndrome, is a rare, but frequently lethal disorder characterized by marked popliteal pterygium associated with multiple congenital malformations. Using Affymetrix 250K SNP array genotyping and homozygosity mapping, we mapped this malformation syndrome to chromosomal region 21q22.3. Direct sequencing of RIPK4 (receptor-interacting serine/threonine kinase protein 4) showed a homozygous transversion (c.362T>A) that causes substitution of a conserved isoleucine with asparagine at amino acid position 121 (p.Ile121Asn) in the serine/threonine kinase domain of the protein. Additional pathogenic mutations-a homozygous transition (c.551C>T) that leads to a missense substitution (p.Thr184Ile) at a conserved position and a homozygous one base-pair insertion mutation (c.777_778insA) predicted to lead to a premature stop codon (p.Arg260ThrfsX14) within the kinase domain-were observed in two families. Molecular modeling of the kinase domain showed that both the Ile121 and Thr184 positions are critical for the protein's stability and kinase activity. Luciferase reporter assays also demonstrated that these mutations are critical for the catalytic activity of RIPK4. RIPK4 mediates activation of the nuclear factor-κB (NF-κB) signaling pathway and is required for keratinocyte differentiation and craniofacial and limb development. The phenotype of Ripk4(-/-) mice is consistent with the human phenotype presented herein. Additionally, the spectrum of malformations observed in the presented families is similar, but less severe than the conserved helix-loop-helix ubiquitous kinase (CHUK)-deficient human fetus phenotype; known as Cocoon syndrome; this similarity indicates that RIPK4 and CHUK might function via closely related pathways to promote keratinocyte differentiation and epithelial growth.     

Correction to: Stress impact of liposomes loaded with ciprofloxacin on the expression level of MepA and NorB efflux pumps of methicillin‑resistant Staphylococcus aureus

International Microbiology -     

Control of virulence by the two-component system CiaR/H is mediated via HtrA, a major virulence factor of Streptococcus pneumoniae

The CiaR/H two-component system is involved in regulating virulence and competence in Streptococcus pneumoniae. The system is known to regulate many genes, including that for high-temperature requirement A (HtrA). This gene has been implicated in the ability of the pneumococcus to colonize the nasopharynx of infant rats. We reported previously that deletion of the gene for HtrA made the pneumococcal strains much less virulent in mouse models, less able to grow at higher temperatures, and more sensitive to oxidative stress. In this report, we show that the growth phenotype as well as sensitivity to oxidative stress of Delta ciaR mutant was very similar to that of a Delta htrA mutant and that the expression of the HtrA protein was reduced in a ciaR-null mutant. Both the in vitro phenotype and the reduced virulence of Delta ciaR mutant could be restored by increasing the expression of HtrA.     

Oral phosphatidylcholine pretreatment alleviates the signs of experimental rheumatoid arthritis

Introduction  

Phosphatidylcholine and phosphatidylcholine-derived metabolites exhibit anti-inflammatory properties in various stress conditions. We hypothesized that dietary phosphatidylcholine may potentially function as an anti-inflammatory substance and may decrease inflammatory activation in a chronic murine model of rheumatoid arthritis (collagen-induced arthritis).