Search

Melanoma differentiation-associated gene-5 (MDA5) recognizes distinct subsets of viruses including Encephalomyocarditis virus (EMCV) of picornavirus family, but the molecular mechanisms underlying the specificity of the viral recognition of MDA5 in immune cells remain obscure. DHX29 is a RNA helicase required for the translation of 5’ structured mRNA of host and many picornaviruses (such as EMCV). We identify that DXH29 as a key RNA co-sensor, plays a significant role for specific recognition and triggering anti-EMCV immunity. We have observed that DHX29 regulates MDA5-, but not RIG-I-, mediated type I interferon signaling by preferentially interacting with structured RNAs and specifically with MDA5 for enhancing MDA5-dsRNA binding affinity. Overall, our results identify a critical role for DHX29 in innate immune response and provide molecular insights into the mechanisms by which DHX29 recognizes 5’ structured EMCV RNA and interacts with MDA5 for potent type I interferon signaling and antiviral immunity. [ABSTRACT FROM AUTHOR]

Many organisms, including the fathead minnow (Pimephales promelas), a toxicological model organism, establish social hierarchies. The social rank of each male in a population is under the control of the hypothalamic-pituitary-gonadal (HPG) axis mainly through regulation of circulating androgen concentrations, which in turn drive the expression of secondary sex characteristics (SSCs). As dominant and subordinate males in an exposure study are initially under different physiological conditions (i.e., differing plasma androgen concentrations), we proposed that they belong to different subpopulations in the context of exposure to compounds that may interact with the HPG axis. Using a meta-analysis of our data from several previously published studies, we corroborated the hypothesis that social status, as indicated by SSCs, results in distinct clusters (eigenvalues >0.8 explaining >80% of variability) with differential expression of plasma vitellogenin, a commonly used biomarker of exposure to contaminants of emerging concern (CEC). Furthermore, we confirmed our predictions that exposure to estrogenic CECs would homogenize plasma vitellogenin response (E1: cluster mean SSC values decreased to 4.33 and 4.86 relative to those of control; E2: decreased to 4.8 and 5.37) across the social hierarchy. In contrast, serotonin-specific reuptake inhibitors expand this response range (cluster mean SSC increased to 5.21 and 6.5 relative to those of control). Our results demonstrated that social hierarchies in male fathead minnows result in heterogeneous responses to chemical exposure. These results represent a cautionary note for the experimental design of single-sex exposure studies. We anticipate our study to be a starting point for the re-evaluation of toxicological data analyses in single sex exposure experiments. [ABSTRACT FROM AUTHOR]

The pine aphid Cinara pinitabulaeformis Zhang et Zhang is the main pine pest in China, it causes pine needles to produce dense dew (honeydew) which can lead to sooty mold (black filamentous saprophytic ascomycetes). Although common chemical and physical strategies are used to prevent the disease caused by C. pinitabulaeformis Zhang et Zhang, new strategies based on biological and/or genetic approaches are promising to control and eradicate the disease. However, there is no information about genomics, proteomics or transcriptomics to allow the design of new control strategies for this pine aphid. We used next generation sequencing technology to sequence the transcriptome of C. pinitabulaeformis Zhang et Zhang and built a transcriptome database. We identified 80,259 unigenes assigned for Gene Ontology (GO) terms and information for a total of 11,609 classified unigenes was obtained in the Clusters of Orthologous Groups (COGs). A total of 10,806 annotated unigenes were analyzed to identify the represented biological pathways, among them 8,845 unigenes matched with 228 KEGG pathways. In addition, our data describe propagative viruses, nutrition-related genes, detoxification related molecules, olfactory related receptors, stressed-related protein, putative insecticide resistance genes and possible insecticide targets. Moreover, this study provides valuable information about putative insecticide resistance related genes and for the design of new genetic/biological based strategies to manage and control C. pinitabulaeformis Zhang et Zhang populations. [ABSTRACT FROM AUTHOR]

The susceptibility of a dietary protein to proteolytic degradation by digestive enzymes, such as gastric pepsin, provides information on the likelihood of systemic exposure to a structurally intact and biologically active macromolecule, thus informing on the safety of proteins for human and animal consumption. Therefore, the purpose of standardized in vitro degradation studies that are performed during protein safety assessments is to distinguish whether proteins of interest are susceptible or resistant to pepsin degradation via a study design that enables study-to-study comparison. Attempting to assess pepsin degradation under a wide-range of possible physiological conditions poses a problem because of the lack of robust and consistent data collected under a large-range of sub-optimal conditions, which undermines the needs to harmonize in vitro degradation conditions. This report systematically compares the effects of pH, incubation time, and pepsin-to-substrate protein ratio on the relative degradation of five dietary proteins: three pepsin susceptible proteins [ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco), horseradish peroxidase (HRP), hemoglobin (Hb)], and two pepsin resistant proteins [lipid transfer protein (LTP) and soybean trypsin inhibitor (STI)]. The results indicate that proteins susceptible to pepsin degradation are readily distinguishable from pepsin-resistant proteins when the reaction conditions are within the well-characterized optima for pepsin. The current standardized in vitro pepsin resistant assay with low pH and high pepsin-to-substrate ratio fits this purpose. Using non-optimal pH and/or pepsin-to-substrate protein ratios resulted in susceptible proteins no longer being reliably degraded by this stomach enzyme, which compromises the ability of this in vitro assay to distinguish between resistant and susceptible proteins and, therefore, no longer providing useful data to an overall weight-of-evidence approach to assessing safety of proteins. [ABSTRACT FROM AUTHOR]

Caldicellulosiruptor bescii encodes at least six unique multimodular glycoside hydrolases crucial for plant cell wall polysaccharides degradation, with each having two catalytic domains separated by two to three carbohydrate binding modules. Among the six enzymes, three have one N- or C-terminal GH5 domain with identical amino acid sequences. Despite a few reports on some of these multimodular enzymes, little is known about how the conserved GH5 domains behave, which are believed to be important due to the gene duplication. We thus cloned a representative GH5 domain from the C-terminus of a multimodular protein, i.e. the bifunctional cellulase/mannanase CbCel9B/Man5A which has been reported, and expressed it in Escherichia coli. Without any appending CBMs, the recombinant CbMan5A was still able to hydrolyze a variety of mannan substrates with different backbone linkages or side-chain decorations. While CbMan5A displayed the same pH optimum as CbCel9B/Man5A, it had an increased optimal temperature (90°C) and moreover, was activated by heating at 70°C and 80°C, a property not ever reported for the full-length protein. The turnover numbers of CbMan5A on mannan substrates were, however, lower than those of CbCel9B/Man5A. These data suggested that evolution of CbMan5A and the other domains into a single polypeptide is not a simple assembly; rather, the behavior of one module may be affected by the other ones in the full-length enzyme. The differential scanning calorimetry analysis further indicated that heating CbMan5A was not a simple transition state process. To the best knowledge of the authors, CbMan5A is the first glycoside hydrolase with thermal activation property identified from a multimodular bifunctional enzyme. [ABSTRACT FROM AUTHOR]

N-glycans play important roles in various pathophysiological processes and can be used as clinical diagnosis markers. However, plasma N-glycans change and their pathophysiological significance in the setting of hypercholesterolemia, a major risk factor for atherosclerosis, is unknown. Here, we collected plasma from both hypercholesterolemic patients and cholesterol-fed hypercholesterolemic rabbits, and determined the changes in the whole-plasma N-glycan profile by electrospray ionization mass spectrometry. We found that both the hypercholesterolemic patients and rabbits showed a dramatic change in their plasma glycan profile. Compared with healthy subjects, the hypercholesterolemic patients exhibited higher plasma levels of a cluster of high-mannose and complex/hybrid N-glycans (mainly including undecorated or sialylated glycans), whereas only a few fucosylated or fucosylated and sialylated N-glycans were increased. Additionally, cholesterol-fed hypercholesterolemic rabbits also displayed increased plasma levels of high-mannose in addition to high complex/hybrid N-glycan levels. The whole-plasma glycan profiles revealed that the plasma N-glycan levels were correlated with the plasma cholesterol levels, implying that N-glycans may be a target for treatment of hypercholesterolemia. [ABSTRACT FROM AUTHOR]

With the use of iTRAQ technique, a multifactorial comparative proteomic study can be performed. In this study, to obtain an overview of ethanol, CYP2E1 and gender effects on liver injury and gain more insight into the underlying molecular mechanism, mouse liver proteomes were quantitatively analyzed using iTRAQ under eight conditions including mice of different genders, wild type versus CYP2E1 knockout, and normal versus alcohol diet. A series of statistical and bioinformatic analyses were explored to simplify and clarify multifactorial comparative proteomic data. First, with the Principle Component analysis, six proteins, CYP2E1, FAM25, CA3, BHMT, HIBADH and ECHS1, involved in oxidation reduction, energy and lipid metabolism and amino acid metabolism, were identified as the most differentially expressed gene products across all of the experimental conditions of our chronic alcoholism model. Second, hierarchical clustering analysis showed CYP2E1 knockout played a primary role in the overall differential protein expression compared with ethanol and gender factors. Furthermore, pair-wise multiple comparisons have revealed that the only significant expression difference lied in wild-type and CYP2E1 knockout mice both treated with ethanol. Third, K-mean clustering analysis indicated that the CYP2E1 knockout had the reverse effect on ethanol induced oxidative stress and lipid oxidation. More importantly, IPA analysis of proteomic data inferred that the gene expressions of two upstream regulators, NRF2 and PPARα, regulated by chronic alcohol feeding and CYP2E1 knockout, are involved in ethanol induced oxidative stress and lipid oxidation. The present study provides an effectively comprehensive data analysis strategy to compare multiple biological factors, contributing to biochemical effects of alcohol on the liver. The mass spectrometry proteomics data have been deposited to the ProteomeXchange with data set identifier of PXD000635. [ABSTRACT FROM AUTHOR]