240 research outputs found
Aedes aegypti CLIPB9 activates prophenoloxidase-3 in the presence of CLIPA14 after fungal infection
Melanization is an integral part of the insect defense system and is often induced by pathogen invasion. Phenoloxidases (POs) are critical enzymes that catalyze melanin formation. PO3 is associated with the antifungal response of the mosquito, Aedes aegypti, but the molecular mechanism of the prophenoloxidase-3 (PPO3) activation is unclear. Here we report that PPO3 cleavage activation is mediated by a clip-domain serine protease, CLIPB9. We purified recombinant CLIPB9 and found that it cleaved PPO3 and increased PO activity in the hemolymph. We then identified CLIPA14 (a serine protease homolog) by co-immunoprecipitation using anti-CLIPB9 antibody. After being cleaved by CLIPB9, Ae. aegypti CLIPA14 acted as a cofactor for PPO3 activation. In addition, dsRNA co-silencing of CLIPB9 and CLIPA14 genes reduced melanization after infection with the entomopathogen, Beauveria bassiana, making the adult mosquitoes more sensitive to fungal infection. These results illustrate the roles of CLIPB9 and CLIPA14 in the PPO activation pathway and revealed the complexity of the upstream serine protease network controlling melanization
Dietary Intervention to Reduce <em>E. coli</em> Infectious Diarrhea in Young Pigs
Postweaning piglets are immediately imposed to remarkable environmental and psychosocial stressors, which adversely affect their intestinal development and health and predispose them to diarrhea. The ratio of postweaning mortality is 6β10% and may rise up to 20% with poor management strategies. Diarrhea per se accounts for 20β30% of cases of mortality in weanling pigs. E. coli postweaning diarrhea is one of the most important causes of postweaning diarrhea in pigs. This diarrhea is responsible for huge economic losses due to high mortality and morbidity, weight loss, and cost of medication. Burgeoning evidence suggested feed-based intervention are one of the promising measures to prevent postweaning diarrhea and to enhance overall health of weaned pigs. Although the exact protective mechanisms may vary and are still not completely understood, a number of feed ingredients or feed additives are marketed to assist in boosting intestinal immunity and regulating gut microbiota. The promising results have been demonstrated in several nutrients (i.e., functional amino acids, organic acids, micro minerals, nondigestible carbohydrates, and antimicrobial peptides), non-nutrients (i.e., phytochemicals and probiotics), and many other feed additives. The efficiencies of each candidate may differ based on their exact modes of action, the basal diet formulation, and the health status of pigs
Surrogate-Driven Multi-Objective Predictive Control for Electric Vehicular Platoon
This paper proposes a surrogate-driven multi-objective predictive control (SMPC) strategy to address the dynamics uncertainty and multi-objective optimization issues of electric vehicular platoon (EVP). A surrogate-driven model is established with subspace identification to alleviate the adverse effects of uncertain dynamics for EVP. Then, a subspace predictor-based distributed surrogate-driven model predictive controller is developed for EVP. To mitigate conflicts among multiple optimization objectives involving driving safety, driving comfort and energy economy, a multi-objective cost function with the predictive sequence is designed. To this end, a grey wolf optimizer is suggested to guide the search towards diverse solutions, aiming to achieve globally optimal trade-offs among conflicting multiple objectives. In this way, the SMPC strategy is constructed, and its stability is theoretically proven. Finally, several experiments are carried out on a co-simulation vehicular platoon platform with the IPG-CarMaker software. The experimental results validate the effectiveness of the proposed SMPC strategy
Deterministic preparation of supersinglets with collective spin projections
We introduce a procedure to generate supersinglets, the multipartite
generalization of angular momentum singlet states. A supersinglet is defined as
a total spin zero state consisting of spin- particles. They are
highly entangled and have zero spin variance in any direction, and as such are
potentially useful for quantum metrology. Our scheme is based on projective
measurements that measure the collective spin of the whole spin ensemble. A
local unitary rotation is applied conditionally on the measurement outcome,
such as to maximize the probability of obtaining spin zero on the subsequent
measurement. The sequence is repeated in the - and -basis until
convergence is obtained towards the supersinglet state. Our sequence works
regardless of the initial state, and no postselection is required. Due to the
use of strong projective measurements, very fast convergence towards zero spin
variance is obtained. We discuss an example implementation using quantum
nondemolition measurements in atomic ensembles, and perform numerical
simulations to demonstrate the procedure
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Localized Epigenetic Changes Induced by DH Recombination Restricts Recombinase to DJH Junctions
Immunoglobulin heavy chain (Igh) genes are assembled by sequential rearrangements of diversity (DH) and variable (VH) gene segments. Three critical constraints govern VH recombination. These include timing (VH recombination follows DH recombination), precision (VHs recombine only to DJH junctions) and allele specificity (VH recombination is restricted to DJH recombined alleles). We provide a model for these universal features of VH recombination. Analyses of DJH recombined alleles revealed that DJH junctions were selectively epigenetically marked, became nuclease sensitive and bound RAG proteins, thereby permitting DH-associated recombination signal sequences to initiate the second step of Igh gene assembly. We propose that VH recombination is precise because these changes did not extend to germline DH gene segments located 5β² of the DJH junction
MiRNA-Directed Regulation of VEGF and Other Angiogenic Factors under Hypoxia
MicroRNAs (miRNAs) are a class of 20β24 nt non-coding RNAs that regulate gene expression primarily through post-transcriptional repression or mRNA degradation in a sequence-specific manner. The roles of miRNAs are just beginning to be understood, but the study of miRNA function has been limited by poor understanding of the general principles of gene regulation by miRNAs. Here we used CNE cells from a human nasopharyngeal carcinoma cell line as a cellular system to investigate miRNA-directed regulation of VEGF and other angiogenic factors under hypoxia, and to explore the principles of gene regulation by miRNAs. Through computational analysis, 96 miRNAs were predicted as putative regulators of VEGF. But when we analyzed the miRNA expression profile of CNE and four other VEGF-expressing cell lines, we found that only some of these miRNAs could be involved in VEGF regulation, and that VEGF may be regulated by different miRNAs that were differentially chosen from 96 putative regulatory miRNAs of VEGF in different cells. Some of these miRNAs also co-regulate other angiogenic factors (differential regulation and co-regulation principle). We also found that VEGF was regulated by multiple miRNAs using different combinations, including both coordinate and competitive interactions. The coordinate principle states that miRNAs with independent binding sites in a gene can produce coordinate action to increase the repressive effect of miRNAs on this gene. By contrast, the competitive principle states when multiple miRNAs compete with each other for a common binding site, or when a functional miRNA competes with a false positive miRNA for the same binding site, the repressive effects of miRNAs may be decreased. Through the competitive principle, false positive miRNAs, which cannot directly repress gene expression, can sometimes play a role in miRNA-mediated gene regulation. The competitive principle, differential regulation, multi-miRNA binding sites, and false positive miRNAs might be useful strategies in the avoidance of unwanted cross-action among genes targeted by miRNAs with multiple targets
Hyperchloremia Is Associated With Poorer Outcome in Critically Ill Stroke Patients
Background and Purpose: This study aims to explore the cause and predictive value of hyperchloremia in critically ill stroke patients.Materials and Methods: We conducted a retrospective study of a prospectively collected database of adult patients with first-ever acute ischemic stroke (AIS) or intracerebral hemorrhage (ICH) admitted to the neurointensive care unit (NICU) of a university-affiliated hospital, between January 2013 and December 2016. Patients were excluded if admitted beyond 72 h from onset, if they required neurocritical care for less than 72 h, and were treated with hypertonic saline within 72 h or had creatinine clearance less than 15 mL/min.Results: Of 405 eligible patients, the prevalence of hyperchloremia ([Clβ] β₯ 110 mmol/L) was 8.6% at NICU admission ([Clβ]0) and 17.0% within 72 h ([Clβ]max). Thirty-eight (9.4%) patients had new-onset hyperchloremia and 110 (27.1%) had moderate increase in chloride (Ξ[Clβ] β₯ 5 mmol/L; Ξ[Clβ] = [Clβ]max β [Clβ]0) in the first 72 h after admission, which were found to be determined by the sequential organ failure assessment score in multivariate logistic regression analysis. Neither total fluid input nor cumulative fluid balance had significant association with such chloride disturbance. New-onset hyperchloremia and every 5 mmol/L increment in Ξ[Clβ] were both associated with increased odds of 30-day mortality and 6-month poor outcome, although no independent significance was found in multivariate models.Conclusion: Hyperchloremia tends to occur in patients more severely affected by AIS and ICH. Although no independent association was found, new-onset hyperchloremia and every 5 mmol/L increment in Ξ[Clβ] were related to poorer outcome in critically ill AIS and ICH patients.Subject terms: clinical studies, intracranial hemorrhage, ischemic stroke, mortality/survival, quality and outcomes
Nutritional Intervention for the Intestinal Development and Health of Weaned Pigs
Weaning imposes simultaneous stress, resulting in reduced feed intake, and growth rate, and increased morbidity and mortality of weaned pigs. Weaning impairs the intestinal integrity, disturbs digestive and absorptive capacity, and increases the intestinal oxidative stress, and susceptibility of diseases in piglets. The improvement of intestinal development and health is critically important for enhancing nutrient digestibility capacity and disease resistance of weaned pigs, therefore, increasing their survival rate at this most vulnerable stage, and overall productive performance during later stages. A healthy gut may include but not limited several important features: a healthy proliferation of intestinal epithelial cells, an integrated gut barrier function, a preferable or balanced gut microbiota, and a well-developed intestinal mucosa immunity. Burgeoning evidence suggested nutritional intervention are one of promising measures to enhance intestinal health of weaned pigs, although the exact protective mechanisms may vary and are still not completely understood. Previous research indicated that functional amino acids, such as arginine, cysteine, glutamine, or glutamate, may enhance intestinal mucosa immunity (i.e., increased sIgA secretion), reduce oxidative damage, stimulate proliferation of enterocytes, and enhance gut barrier function (i.e., enhanced expression of tight junction protein) of weaned pigs. A number of feed additives are marketed to assist in boosting intestinal immunity and regulating gut microbiota, therefore, reducing the negative impacts of weaning, and other environmental challenges on piglets. The promising results have been demonstrated in antimicrobial peptides, clays, direct-fed microbials, micro-minerals, milk components, oligosaccharides, organic acids, phytochemicals, and many other feed additives. This review summarizes our current understanding of nutritional intervention on intestinal health and development of weaned pigs and the importance of mechanistic studies focusing on this research area
Simultaneous Determination of 49 Antibiotics Residues in Pork by a Modified QuEChERS Method Based on Silanized Melamine Sponge Coupled with Ultra-high Performance Liquid Chromatography-Tandem Mass Spectrometry
Two new types of elastic porous silanized melamine sponges (MeS) were prepared by silylation reaction using octadecyltrichlorosilane (OTS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (ATS), which were respectively designated as OTS@MeS and ATS@MeS. The silanized sponges were used to develop a modified quick, easy, check, effective, rugged, and safe (QuEChERS) method that can quickly and efficiently separate interfering matrices from the extract through spontaneous solution infiltration and physical extrusion. In this study, an analytical method using the modified QuEChERS procedure combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established for the simultaneous determination of 49 antibiotic residues in pork. Samples were extracted with 10 mL of acetonitrile containing 0.1% acetic acid, and then salted out with 2.0 g of Na2SO4 and 0.5 g of NaCl. After centrifugation, a 1 mL aliquot of the supernatant was cleaned up with a mixture of OTS@MeS and ATS@MeS. The chromatographic separation was conducted on an Agilent ZORBAX Eclipse Plus C18 column with gradient elution using a mobile phase comprised of methanol and aqueous solution (methanol/water, 5:95, V/V) containing 0.1% formic acid and 5 mmol/L ammonium acetate. The qualitative and quantitative detection were performed by multiple-reaction monitoring (MRM) using an electrospray ionization source in the positive ion mode. The results showed that the correlation coefficients for all analytes were greater than 0.999. The matrix effects (ME) were in the range of β13.5%β10.9%. The limits of detection (LOQ) and quantitation (LOQ) were 0.1β10.0 and 0.3β33.3 ΞΌg/kg, respectively. The recoveries at three spiked levels ranged from 65.0% to 112.7%, with intra- and interday relative standard deviations (RSDs) of 0.3%β11.8% and 2.4%β18.4%, respectively. The developed method was simple, rapid, highly sensitive and accurate, and could be used for the efficient and rapid determination of the 49 antibiotics residues in pork
Promoters, enhancers, and transcription target RAG1 binding during V(D)J recombination
RAG1 binding to TCR gene elements is dictated by transcriptional control elements and by transcription itself; these findings provide direct confirmation of the long-held accessibility model
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