Important role of Bacillus subtilis as a probiotic and vaccine carrier in animal health maintenance.

Bacillus subtilis is a widespread Gram-positive facultative aerobic bacterium that is recognized as generally safe. It has shown significant application value and great development potential in the animal farming industry. As a probiotic, it is frequently used as a feed growth supplement to effectively replace antibiotics due to its favourable effects on regulating the intestinal flora, improving intestinal immunity, inhibiting harmful microorganisms, and secreting bioactive substances. Consequently, the gut health and disease resistance of farmed animals can be improved. Both vegetative and spore forms of B. subtilis have also been utilized as vaccine carriers for delivering the antigens of infectious pathogens for over a decade. Notably, its spore form is regarded as one of the most prospective for displaying heterologous antigens with high activity and stability. Previously published reviews have predominantly focused on the development and applications of B. subtilis spore surface display techniques. However, this review aims to summarize recent studies highlighting the important role of B. subtilis as a probiotic and vaccine carrier in maintaining animal health. Specifically, we focus on the beneficial effects and underlying mechanisms of B. subtilis in enhancing disease resistance among farmed animals as well as its potential application as mucosal vaccine carriers. It is anticipated that B. subtilis will assume an even more prominent role in promoting animal health with in-depth research on its characteristics and genetic manipulation tools.

Pan-Genomic and Transcriptomic Analyses of Marine Pseudoalteromonas agarivorans Hao 2018 Revealed Its Genomic and Metabolic Features.

The genomic and carbohydrate metabolic features of Pseudoalteromonas agarivorans Hao 2018 (P. agarivorans Hao 2018) were investigated through pan-genomic and transcriptomic analyses, and key enzyme genes that may encode the process involved in its extracellular polysaccharide synthesis were screened. The pan-genome of the P. agarivorans strains consists of a core-genome containing 2331 genes, an accessory-genome containing 956 genes, and a unique-genome containing 1519 genes. Clusters of Orthologous Groups analyses showed that P. agarivorans harbors strain-specifically diverse metabolisms, probably representing high evolutionary genome changes. The Kyoto Encyclopedia of Genes and Genomes and reconstructed carbohydrate metabolic pathways displayed that P. agarivorans strains can utilize a variety of carbohydrates, such as d-glucose, d-fructose, and d-lactose. Analyses of differentially expressed genes showed that compared with the stationary phase (24 h), strain P. agarivorans Hao 2018 had upregulated expression of genes related to the synthesis of extracellular polysaccharides in the logarithmic growth phase (2 h), and that the expression of these genes affected extracellular polysaccharide transport, nucleotide sugar synthesis, and glycosyltransferase synthesis. This is the first investigation of the genomic and metabolic features of P. agarivorans through pan-genomic and transcriptomic analyses, and these intriguing discoveries provide the possibility to produce novel marine drug lead compounds with high biological activity.

Effect of Different Initial Fermentation pH on Exopolysaccharides Produced by Pseudoalteromonas agarivorans Hao 2018 and Identification of Key Genes Involved in Exopolysaccharide Synthesis via Transcriptome Analysis.

Exopolysaccharides (EPSs) are carbohydrate polymers produced and secreted by microorganisms. In a changing marine environment, EPS secretion can reduce damage from external environmental disturbances to microorganisms. Meanwhile, EPSs have promising application prospects in the fields of food, cosmetics, and pharmaceuticals. Changes in external environmental pH have been shown to affect the synthesis of EPSs in microorganisms. In this study, we analyzed the effects of different initial fermentation pHs on the production, monosaccharide composition, and antioxidant activity of the EPSs of Pseudoalteromonas agarivorans Hao 2018. In addition, the transcriptome sequence of P. agarivorans Hao 2018 under different initial fermentation pH levels was determined. GO and KEGG analyses showed that the differentially expressed genes were concentrated in the two-component regulatory system and bacterial chemotaxis pathways. We further identified the expression of key genes involved in EPS synthesis during pH changes. In particular, the expression of genes encoding the glucose/galactose MFS transporter, phosphomannomutase, and mannose-1-phosphate guanylyltransferase was upregulated when the environmental pH increased, thus promoting EPS synthesis. This study not only contributes to elucidating the environmental adaptation mechanisms of P. agarivorans, but also provides important theoretical guidance for the directed development of new products using biologically active polysaccharides.

Optimizing Movement for Maximizing Lifetime of Mobile Sensors for Covering Targets on a Line.

Given a set of sensors distributed on the plane and a set of Point of Interests (POIs) on a line segment, a primary task of the mobile wireless sensor network is to schedule covering the POIs by the sensors, such that each POI is monitored by at least one sensor. For balancing the energy consumption, we study the min-max line barrier target coverage (LBTC) problem which aims to minimize the maximum movement of the sensors from their original positions to their final positions at which the coverage is composed. We first proved that when the radius of the sensors are non-uniform integers, even 1-dimensional LBTC (1D-LBTC), a special case of LBTC in which the sensors are distributed on the line segment instead of the plane, is NP -hard. The hardness result is interesting, since the continuous version of LBTC to cover a given line segment instead of the POIs is known polynomial solvable. Then we present an exact algorithm for LBTC with uniform radius and sensors distributed on the plane, via solving the decision version of LBTC. We argue that our algorithm runs in time O ( n 2 log n ) and produces an optimal solution to LBTC. The time complexity compares favorably to the state-of-art runtime O ( n 3 log n ) of the continuous version which aims to cover a line barrier instead of the targets. Last but not the least, we carry out numerical experiments to evaluate the practical performance of the algorithms, which demonstrates a practical runtime gain comparing with an optimal algorithm based on integer linear programming.

Isolation, Characterization, and Pharmaceutical Applications of an Exopolysaccharide from Aerococcus Uriaeequi.

Many marine bacteria secrete exopolysaccharides (EPSs), which are made up of a substantial component of the macro-molecules surrounding cells. Recently, the wide demand for EPSs for food, cosmetics, pharmaceutical and other applications has led to great interest in them. In this study, an EPS produced by marine bacteria Aerococcus uriaeequi HZ strains (EPS-A) was isolated and purified to examine its structure and biological function. The molecular weight of EPS-A analyzed by high-performance liquid gel filtration chromatography (HPGFC) is found to have a number average of 2.22 × 105 and weight average of 2.84 × 105, respectively. High-performance liquid chromatography (HPLC) and Fourier-transform⁻infrared (FT⁻IR) analysis indicate that EPS-A was a polysaccharide composed of glucose and a little mannose. In addition, the flocculating rate of sewage of EPS-A was 79.90%. The hygroscopicity studies showed that hygroscopicity of EPS-A was higher than chitosan but lower than that of sodium hyaluronate. The moisture retention of EPS-A showed similar retention activity to both chitosan and sodium hyaluronate. EPS-A also can scavenge free radicals including both OH• free radical and O2•- free radical and the activity to O2•- free radical is similar to vitamin C. Safety assessment on mice indicated that the EPS-A is safe for external use and oral administration. EPS-A has great potential for applications in medicine due to its characteristics mentioned above.

Enhanced anti-proliferative efficacy of epothilone B loaded with Escherichia coli Nissle 1917 bacterial ghosts on the HeLa cells by mitochondrial pathway of apoptosis.

Epothilones constitute a new class of microtubule-stabilizing anti-cancer agents with promising preclinical and clinical activity. However, its systemic application still causes some toxic side effects. To reduce these undesired effects, advanced drug delivery systems based on cell targeting carriers are needed currently. In this study, the high quality bacterial ghosts of the probiotic Escherichia coli Nissle 1917 (EcN) were prepared in a large scale and retained fully intact surface structures for specific attachment to mammalian cells. The EcN ghosts could be efficiently loaded with the low hydrophilic drug Epothilone B (Epo B) and the maximal load efficiency was approximately 2.5% (w/w). Cytotoxicity assays revealed that Epo B-ghosts exhibited enhanced anti-proliferative properties on the HeLa cells. The Epo B associated with EcN ghosts was more cytotoxic at least 10 times than the free Epo B at the same concentrations. Apoptosis assays showed that both Epo B-ghosts and free Epo B induced time course-dependent apoptosis and necrosis in HeLa cells, respectively. While the former induced more apoptosis and necrosis than the latter. Furthermore, the cytochrome C release and the activation of caspase-3 were more remarkable after treatment with the Epo B-ghosts compared to the free Epo B, which implied that Epo B-ghosts might more effectively induce the apoptosis mediated by mitochondrial pathway in HeLa cells. Therefore, the higher anti-proliferative effects of the Epo B-ghosts on the HeLa cells were mediated by mitochondrial pathway of apoptosis. The EcN ghosts may provide a useful drug delivery carrier for drug candidates in cancer therapy.

Generation of biotechnology-derived Flavobacterium columnare ghosts by PhiX174 gene E-mediated inactivation and the potential as vaccine candidates against infection in grass carp.

Flavobacterium columnare is a bacterial pathogen causing high mortality rates for many freshwater fish species. Fish vaccination with a safe and effective vaccine is a potential approach for prevention and control of fish disease. Here, in order to produce bacterial ghost vaccine, a specific Flavobacterium lysis plasmid pBV-E-cat was constructed by cloning PhiX174 lysis gene E and the cat gene with the promoter of F. columnare into the prokaryotic expression vector pBV220. The plasmid was successfully electroporated into the strain F. columnare G4cpN22 after curing of its endogenous plasmid. F. columnare G4cpN22 ghosts (FCGs) were generated for the first time by gene E-mediated lysis, and the vaccine potential of FCG was investigated in grass carp (Ctenopharyngodon idellus) by intraperitoneal route. Fish immunized with FCG showed significantly higher serum agglutination titers and bactericidal activity than fish immunized with FKC or PBS. Most importantly, after challenge with the parent strain G4, the relative percent survival (RPS) of fish in FCG group (70.9%) was significantly higher than FKC group (41.9%). These results showed that FCG could confer immune protection against F. columnare infection. As a nonliving whole cell envelope preparation, FCG may provide an ideal alternative to pathogen-based vaccines against columnaris in aquaculture.

Anti-atherosclerotic activity of platycodin D derived from roots of Platycodon grandiflorum in human endothelial cells.

This study examined the effects of platycodin D (PD), a triterpene saponin from the the root of Platycodon grandiflorum A.DC on human umbilical vein endothelial cells (HUVECs) in vitro, which were pre-treated with PD (0.01, 0.15, 0.25 mg/mL), respectively, and treated with 50 mg/L oxidized low-density lipoprotein (oxLDL). The levels of nitric oxide (NO) and malonaldehyde (MAD) in the culture medium, vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1) mRNA expression in endothelium cells and the adhesion of monocytes to endothelial cells were measured. The results showed that PD increased NO concentration and decreased MDA level induced by oxLDL in the medium of endothelial cells. Moreover, PD significantly inhibited the oxLDL-induced increase in monocyte adhesion to endothelial cells as well as decreasing mRNA expression levels of VCAM-1 and ICAM-1 on these cells. Based on these results, it is suggested that PD is a promising anti-atherosclerotic activity, which is at least in part the result of its increasing NO concentration, reducing the oxLDL-induced cell adhesion molecule expression in endothelial cells and the endothelial adhesion to monocytes.

Discriminability of single-trial EEG during decision-making of cooperation or aggression: a study based on machine learning.

Decision-making is a very important cognitive process in our daily life. There has been increasing interest in the discriminability of single-trial electroencephalogram (EEG) during decision-making. In this study, we designed a machine learning based framework to explore the discriminability of single-trial EEG corresponding to different decisions. For each subject, the framework split the decision-making trials into two parts, trained a feature model and a classifier on the first part, and evaluated the discriminability on the second part using the feature model and classifier. A proposed algorithm and five existing algorithms were applied to fulfill the feature models, and the algorithm Linear Discriminative Analysis (LDA) was used to implement the classifiers. We recruited 21 subjects to participate in Chicken Game (CG) experiments. The results show that there exists the discriminability of single-trial EEG between the cooperation and aggression decisions during the CG experiments, with the classification accuray of 75% (±6%), and the discriminability is mainly from the EEG information below 40 Hz. The further analysis indicates that the contributions of different brain regions to the discriminability are consistent with the existing knowledge on the cognitive mechanism of decision-making, confirming the reliability of the conclusions. This study exhibits that it is feasible to apply machine learning methods to EEG analysis of decision-making cognitive process.

Optimization and evaluation of resveratrol amorphous solid dispersions with a novel polymeric system.

The preparation of amorphous solid dispersions using polymers is a commonly used formulation strategy for enhancing the solubility of poorly water-soluble drugs. However, a single polymer often does not bring significantly enhance the solubility or amorphous stability of a poorly water-soluble drug. We found an application of a unique and novel binary polymeric blend in the preparation of solid dispersions. The main purpose of this study is to optimize and evaluate resveratrol (Res) amorphous solid dispersions with a novel polymeric system of poly (vinyl pyrrolidone) (PVP) and carboxymethyl chitosan (CMCS). The influence of three different release factors, the ratio of CMCS to the polymer mixture (CMCS% = X1), the ratio of Res to the polymer mixture (Res% = X2) and the surfactant (Tween 80 = X3), on the characteristics of released Res at various times (Q5 and Q30) was investigated. The computer optimization and contour plots were used to predict the levels of the independent variables as X1 = 0.17, X2 = 0.10 and X3 = 2.94 for maximized responses of Q5 and Q30. Fourier transform infrared spectroscopy (FTIR) results revealed that each polymer formed hydrogen bonds with Res. The solid performance and physical stability of the optimized ternary dispersions were studied with scanning electron microscopy (SEM), powder X-ray diffraction (XRD), modulated differential scanning calorimetry (MDSC) and dissolution testing. SEM, XRD and MDSC analysis demonstrated that the Res was amorphous, and MDSC showed no evidence of phase separation during storage. Dissolution testing indicated a more than fourfold increase in the apparent solubility of the optimized ternary dispersions, which maintained high solubility after 90 days. In our research, we used CMCS as a new carrier in combination with PVP, which not only improved the in vitro dissolution of Res but also had better stability.

Iterative Weighted Group Thresholding Method for Group Sparse Recovery.

This article proposes a novel iterative weighted group thresholding method for group sparse recovery of signals from underdetermined linear systems. Based on an equivalent weighted group minimization problem with lpp -norm ( ), we derive closed-form solutions for a subproblem with respect to some specific values of p when using the proximal gradient method. Then, we design the corresponding algorithmic framework, including stopping criterion and the method of nonmonotone line search, and prove that the solution sequence generated by the proposed algorithm converges under some mild conditions. Moreover, based on the proposed algorithm, we develop a homotopy algorithm with an adaptively updated group threshold. Extensive computational experiments on the simulated and real data show that our approach is competitive with state-of-the-art methods in terms of exact group selection, estimation accuracy, and computation time.

Comparative study of c-Fos expression in rat dorsal vagal complex and nucleus ambiguus induced by different durations of restraint water-immersion stress.

Restraint water-immersion stress (RWIS) of rats induces vagally-mediated gastric dysfunction. The present work explored the effects of different durations of RWIS on neuronal activities of the dorsal vagal complex (DVC) and the nucleus ambiguous (NA) in rats. Male Wistar rats were exposed to RWIS for 0, 30, 60, 120, or 180 min. Then, a c-Fos immunoperoxidase technique was utilized to assess neuronal activation. Resumptively, c-Fos expression in DVC and NA peaked at 60 min of stress, subsequently decreased gradually with increasing durations of RWIS. Interestingly, the most intense c-Fos expression was observed in the dorsal motor nucleus of the vagus (DMV) during the stress, followed by NA, nucleus of solitary tract (NTS) and area postrema (AP). The peak of c-Fos expression in caudal DMV appeared at 120 min of the stress, slower than that in rostral and intermediate DMV. The c-Fos expression in intermediate and caudal NTS was significantly more intense than that in rostral NTS. These results indicate that the neuronal hyperactivity of DMV, NA, NTS and AP, the primary center that control gastric functions, especially DMV and NA, may play an important role in the disorders of gastric motility and secretion induced by RWIS.

Homotopy Methods Based on $l_{0}$ -Norm for Compressed Sensing.

This paper proposes two homotopy methods for solving the compressed sensing (CS) problem, which combine the homotopy technique with the iterative hard thresholding (IHT) method. The homotopy methods overcome the difficulty of the IHT method on the choice of the regularization parameter value, by tracing solutions of the regularized problem along a homotopy path. We prove that any accumulation point of the sequences generated by the proposed homotopy methods is a feasible solution of the problem. We also show an upper bound on the sparsity level for each solution of the proposed methods. Moreover, to improve the solution quality, we modify the two methods into the corresponding heuristic algorithms. Computational experiments demonstrate effectiveness of the two heuristic algorithms, in accurately and efficiently generating sparse solutions of the CS problem, whether the observation is noisy or not.

Efficient production of safety-enhanced Escherichia coli ghosts by tandem expression of PhiX 174 mutant gene E and staphylococcal nuclease A gene.

The application of bacterial ghosts as vaccines is limited because of their low lysis efficiency and production and the presence of pathogenic islands and/or antibiotic resistance genes within ghost preparations. To overcome these problems, a new lysis plasmid with fusion gene of mutant gene E and staphylococcal nuclease A gene (mE-L-SNA) were constructed and characterized. The new plasmid pBV-mELS could efficiently induce the genetic inactivation of Escherichia coli cultures, accompanied by the intracellular degradation of the genetic material of host cells, devoid of the presence of pathogenic islands and antibiotic resistance genes within ghost preparations. Furthermore, the lysis efficiency of the plasmid pBV-mELS was not affected by bacterial concentration and could reach 99.99995% for E. coli at late-log phase. However, when the 74-bp non-encoding region of the gene mE-L-SNA were deleted or the first T nucleotide of the gene mE-L-SNA were substituted, these resulting genes lost the function of bacteriolysis, which suggested the 74-bp region of the gene mE-L-SNA, especially the first T nucleotide, played a crucial role in enhancement of bacteriolysis. The lysis system with the gene mE-L-SNA had predominance for large-scale production of safety-enhanced bacterial ghosts. The strategy may provide a promising avenue for efficient production of safe bacterial ghost vaccines.

c-Fos expression in the supraoptic nucleus is the most intense during different durations of restraint water-immersion stress in the rat.

Restraint water-immersion stress (RWIS) can induce anxiety, hypothermia, and severe vagally-mediated gastric dysfunction. The present work explored the effects of different durations of RWIS on neuronal activities of the forebrain by c-Fos expression in conscious rats exposed to RWIS for 0, 30, 60, 120, or 180 min. The peak of c-Fos induction was distinct for different forebrain regions. The most intense c-Fos induction was always observed in the supraoptic nucleus (SON), and then in the hypothalamic paraventricular nucleus (PVN), posterior cortical amygdaloid nucleus (PCoA), central amygdaloid nucleus (CeA), and medial prefrontal cortex (mPFC). Moreover, body temperature was reduced to the lowest degree after 60 min of RWIS, and the gastric lesions tended to gradually worsen with the prolonging of RWIS duration. These data strongly suggest that these nuclei participate in the organismal response to RWIS to different degrees, and may be involved in the hypothermia and gastric lesions induced by RWIS.