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Vibrio harveyi can cause infections and diseases in a variety of marine vertebrates and invertebrates, which are harmful to the aquaculture industry. The LuxS quorum-sensing system regulates the expression of virulence factors in a wide variety of pathogenic bacteria. In this study, an in-frame deletion of the luxS gene was constructed to reveal the role of LuxS in the physiology and virulence of V. harveyi. Statistical analysis showed no significant differences in the growth ability, biofilm formation, antibiotic susceptibility, virulence by intraperitoneal injection, and ability of V. harveyi to colonize the spleen and liver of the pearl gentian grouper between the wild-type (WT) and luxS mutant. However, deletion of luxS decreased the secretion of extracellular protease, while increasing swimming and swarming abilities. Simultaneously, a luxS-deleted mutant showed overproduction of lateral flagella, and an intact luxS complemented this defect. Since motility is flagella dependent, 16 V. harveyi flagella biogenesis related genes were selected for further analysis. Based on quantitative real-time reverse transcription-PCR (qRT-PCR), the expression levels of these genes, including the polar flagella genes flaB, flhA, flhF, flhB, flhF, fliS, and flrA and the lateral flagella genes flgA, flgB, fliE, fliF, lafA, lafK, and motY, were significantly upregulated in the ΔluxS: pMMB207 (ΔluxS+) strain as compared with the V. harveyi 345: pMMB207 (WT+) and C-ΔluxS strains during the early, mid-exponential, and stationary growth phases. Our results indicate that LuxS plays an important role in controlling motility, flagella biogenesis, and extracellular protease secretion in V. harveyi.

The drought resistance of psammophytes determines their survival and growth under natural conditions or after transplanting. However, their responses to drought are not well understood. Agriophyllum squarrosum is a pioneer psammophyte in Horqin sandy land’s vegetation community, and Setaria viridis is the climax species. We conducted a pot experiment with both species to study how their physiological characteristics respond to drought and rehydration. We found that watering to 60 and 65% of field capacity (the control) provided more water than was required by A. squarrosum, and its leaves became yellow and slightly wilted. The total chlorophyll content and Fm (maximum fluorescence after dark adaptation) were lower than in the drought treatment, and both decreased after rehydration. With increasing drought duration, the chlorophyll content and Fm of A. squarrosum under moderate and severe drought first increased and then decreased, malondialdehyde levels and membrane permeability increased, but the quantum efficiency of photosystem II (Fv/Fm) decreased. With increasing drought duration and intensity, the relative water content (RWC), chlorophyll content, Fm, and Fv/Fm of S. viridis decreased, but malondialdehyde levels and membrane permeability increased. During the late drought period, levels of A. squarrosum’s three antioxidant enzymes increased to prevent membrane lipid peroxidation; for S. viridis, only peroxidase and superoxide dismutase levels increased. After rehydration, RWC of both plants increased, but the chlorophyll content decreased. Fv/Fm of A. squarrosum and Fm of S. viridis did not recover after severe drought. Our results provide insights into psammophyte adaptation to drought stress to support ecological restoration and reconstruction.

As the global ecosystem has been severely disturbed by an increasing number of human activities at different scales, remote sensing technology, as an effective quantitative measure of environmental quality, has been widely used. The remote sensing ecological index (RSEI) is one of the most popular and comprehensive ecological quality assessment indices based on the remote sensing data. However, the RSEI model exhibits that the ecological environment under natural conditions is not limited by the spatial scales. In addition, the model has major shortcomings in index selection and eigenvector, which greatly limit the application of RSEI. In this paper, the RSEI model is improved and a remote sensing ecological index optimized by the regional scale (RO-RSEI) is proposed. The result of the study, conducted in Shuangyang District, Changchun City, Jilin Province, shows that the RO-RSEI model has regional ecological significance after the introduction of the scale theory of landscape ecology; the index is preferred to solve problems like the RSEI model applied mechanization and baseless index selection. Meanwhile, due to the optimization of the eigenvector contribution of the optimal index, it solves the problems like non-unique model calculation result caused by principal component analysis or even antipodal calculation result. Compared with the RSEI model, the monitoring result of RO-RSEI model can better reflect the regional ecological changes. The improved model offers the possibility of monitoring ecological environment quality with remote sensing big data and provides a scientific basis for future scholars' batch computing.

A previous study confirmed that spotted sea bass (Lateolabrax maculatus), an economically important cultured species in East Asia, is a new host of Aeromonas veronii, which can cause acute death in these fish, but there is little in-depth understanding of this disease. In the present study, the virulence of 10 isolates of A. veronii derived from spotted sea bass was determined. It was found that the 18BJ181 isolate was a virulent strain and led to the fastest death of spotted sea bass. Death was determined to be within in 2-12 h, and resulted in abdominal effusion and varying degrees of hemorrhage in internal organs. Bacterial colonization analysis showed that the bacterial load in the spleen was highest, and was up to 3.1 × 10

Vibrio harveyi is a common aquaculture pathogen causing diseases in a variety of aquatic animals. toxR, a conserved virulence-associated gene in vibrios, is identified in V. harveyi 345, a pathogenic strain isolated from diseased fish. In this study, to gain insight into function of ToxR in V. harveyi, an in-frame deletion of the toxR gene was constructed to reveal the role of ToxR in the physiology and virulence of V. harveyi. The statistical analysis showed no significant differences in the growth ability, motility, extracellular protease secretion, antibiotic susceptibility, virulence by intraperitoneal injection, and the ability of V. harveyi to colonize the spleen and liver tissues of the pearl gentian grouper between the wild-type (WT) and the toxR mutant. However, the deletion of toxR increased the biofilm formation. The structure of the V. harveyi biofilm was further analyzed by using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), and the results showed that deletion of toxR increased the number and density of V. harveyi biofilm. Since biofilm production is flagella, exopolysaccharide (EPS), and lipopolysaccharide (LPS) dependent, 16 of V. harveyi biofilm-related genes were selected for further analysis. Based on quantitative real-time reverse transcription-PCR (qRT-PCR), the expression levels of these genes, including genes flrB, motY, and mshA, flaE, flrA, and gmhD, were significantly up-regulated in the ΔtoxR+ strain as compared with the WT+ and C-ΔtoxR strains during the early and mid-exponential, while epsG, flaA, flaE, flgD, flgE, flrB, flrC, lpxB, motY, mshA, and scrG genes were inhibited because of deletion of the toxR gene in the stationary growth phase. Our results indicate that ToxR plays an important role in controlling the biofilm in V. harveyi.

More and more human activities have caused varying degrees of interference with the ecosystem. As an effective quantitative means of eco-environmental quality, remote sensing has been widely used. The remote sensing ecological index (RSEI) is the most popular ecological evaluation model at present. However, the model is affected by the direction of the eigenvector, and two completely opposite results will appear in the calculation of the model. In the past, researchers often manually judged whether the two results met the expectations according to a priori knowledge to select the appropriate calculation results. With the development of remote sensing big data, applying this artificial discrimination method to eco-environmental monitoring under the background of big data is difficult. Therefore, we test the evolution of the RSEI model eigenvector in time series through large samples. It is found that the results of the two models are completely opposite in space. For any model, changing the order of input bands may result in RSEI also being the opposite. Through the large sample test in different time periods, the eigenvectors of each ecological factor affect the direction of the corresponding RSEI. Therefore, we propose an improved model to judge the characteristic contribution direction of the first principal component by selecting the wet factor, which is less affected by seasonal changes. The model direction can be automatically modified without the intervention of researchers according to subjective experience. The improved model can adapt different periods of RSEI calculation. At the same time, no matter how the input band order changes, the final result direction is correct. The improved model makes it possible to monitor and calculate the eco-environmental quality of remote sensing big data and provides a solid scientific basis for the development of the model through research on the mechanism of the model.

Metastable glycosylated immunogens present challenges for GMP manufacturing. The HIV-1 envelope (Env) glycoprotein trimer is covered by N-linked glycan comprising half its mass and requires both trimer assembly and subunit cleavage to fold into a prefusion-closed conformation. This conformation, the vaccine-desired antigenic state, is both metastable to structural rearrangement and labile to subunit dissociation. Prior reported GMP manufacturing for a soluble trimer stabilized in a near-native state by disulfide (SOS) and Ile-to-Pro (IP) mutations has employed affinity methods based on antibody 2G12, which recognizes only ~30% of circulating HIV strains. Here, we develop a scalable manufacturing process based on commercially available, non-affinity resins, and we apply the process to current GMP (cGMP) production of trimers from clades A and C, which have been found to boost cross-clade neutralizing responses in vaccine-test species. The clade A trimer, which we named “BG505 DS-SOSIP.664”, contained an engineered disulfide (201C-433C; DS) within gp120, which further stabilized this trimer in a prefusion-closed conformation resistant to CD4-induced triggering. BG505 DS-SOSIP.664 was expressed in a CHO-DG44 stable cell line and purified with initial and final tangential flow filtration steps, three commercially available resin-based chromatography steps, and two orthogonal viral clearance steps. The non-affinity purification enabled efficient scale-up, with a 250 L-scale cGMP run yielding 9.6 g of purified BG505 DS-SOSIP.664. Antigenic analysis indicated retention of a prefusion-closed conformation, including recognition by apex-directed and fusion peptide-directed antibodies. The developed manufacturing process was suitable for 50 L-scale production of a second prefusion-stabilized Env trimer vaccine candidate, ConC-FP8v2 RnS-3mut-2G-SOSIP.664, yielding 7.8 g of this consensus clade C trimer. The successful process development and purification scale-up of HIV-1 Env trimers from different clades by using commercially available materials provide experimental demonstration for cGMP manufacturing of trimeric HIV-Env vaccine immunogens, in an antigenically desired conformation, without the use of costly affinity resins.

Vibrio harveyi causes vibriosis in nearly 70% of grouper (Epinephelus sp.), seriously limiting grouper culture. As well as directly inhibiting pathogens, the gut microbiota plays critical roles in immune homeostasis and provides essential health benefits to its host. However, there is still little information about the variations in the immune response to V. harveyi infection and the gut microbiota of grouper. To understand the virulence mechanism of V. harveyi in the pearl gentian grouper, we investigated the variations in the pathological changes, immune responses, and gut bacterial communities of pearl gentian grouper after exposure to differently virulent V. harveyi strains. Obvious histopathological changes were detected in heart, kidney, and liver. In particular, nodules appeared and huge numbers of V. harveyi cells colonized the liver at 12 h postinfection (hpi) with highly virulent V. harveyi. Although no V. harveyi was detected in the gut, the infection simultaneously induced a gut-liver immune response. In particular, the expression of 8 genes associated with cellular immune processes, including genes encoding inflammatory cytokines and receptors, and pattern recognition proteins, was markedly induced by V. harveyi infection, especially with the highly virulent V. harveyi strain. V. harveyi infection also induced significant changes in gut bacterial community, in which Vibrio and Photobacterium increased but Bradyrhizobium, Lactobacillus, Blautia, and Faecalibaculum decreased in the group infected with the highly virulent strain, with accounting for 82.01% dissimilarity. Correspondingly, four bacterial functions related to bacterial pathogenesis were increased by infection with highly virulent V. harveyi, whereas functions involving metabolism and genetic information processing were reduced. These findings indicate that V. harveyi colonizes the liver and induces a gut-liver immune response that substantially disrupts the composition of and interspecies interactions in the bacterial community in fish gut, thereby altering the gut-microbiota-mediated functions and inducing fish death.

The vaccine elicitation of broadly neutralizing antibodies against HIV-1 is a long-sought goal. We previously reported the amino-terminal eight residues of the HIV-1-fusion peptide (FP8) – when conjugated to the carrier protein, keyhole limpet hemocyanin (KLH) – to be capable of inducing broadly neutralizing responses against HIV-1 in animal models. However, KLH is a multi-subunit particle derived from a natural source, and its manufacture as a clinical product remains a challenge. Here we report the preclinical development of recombinant tetanus toxoid heavy chain fragment (rTTHC) linked to FP8 (FP8-rTTHC) as a suitable FP-conjugate vaccine immunogen. We assessed 16 conjugates, made by coupling the 4 most prevalent FP8 sequences with 4 carrier proteins: the aforementioned KLH and rTTHC; the H. influenzae protein D (HiD); and the cross-reactive material from diphtheria toxin (CRM197). While each of the 16 FP8-carrier conjugates could elicit HIV-1-neutralizing responses, rTTHC conjugates induced higher FP-directed responses overall. A Sulfo-SIAB linker yielded superior results over an SM(PEG)2 linker but combinations of carriers, conjugation ratio of peptide to carrier, or choice of adjuvant (Adjuplex or Alum) did not significantly impact elicited FP-directed neutralizing responses in mice. Overall, SIAB-linked FP8-rTTHC appears to be a promising vaccine candidate for advancing to clinical assessment.

An N-terminal peptide of the HIV-1 fusion peptide (FP) with eight amino acid residues (FP8) was conjugated to a recombinant Tetanus Toxoid Heavy Chain Fragment C (rTTHc) as a carrier protein to help boosting immunogenicity against HIV-1. In this rapid communication, a unique algorithm to determine FP-rTTHc conjugation ratio was developed based off the amino acid analysis. Five well recovered amino acids (present in both FP and rTTHc) were used to calculate the conjugation ratio, while proline (present only in rTTHc) was identified and utilized as the intrinsic internal standard for normalization. With this calculation, the assay variability was minimized (

Artemisia halodendron is a widely distributed native plant in China&rsquo, s Horqin sandy land, but few studies have examined its physiological responses to drought and rehydration. To provide more information, we investigated the effects of drought and rehydration on the chlorophyll fluorescence parameters and physiological responses of A. halodendron to reveal the mechanisms responsible for A. halodendron&rsquo, s tolerance of drought stress and the resulting ability to tolerate drought. We found that A. halodendron had strong drought resistance. Its chlorophyll content first increased and then decreased with prolonged drought. Variable chlorophyll fluorescence (Fv) and quantum efficiency of photosystem II (Fv/Fm) decreased, and the membrane permeability and malondialdehyde increased. When plants were subjected to drought stress, superoxide dismutase (SOD) activity degraded under severe drought, but the activities of peroxidase (POD) and catalase (CAT) and the contents of soluble proteins, soluble sugars, and free proline increased. Severe drought caused wilting of A. halodendron leaves and the leaves failed to recover even after rehydration. After rehydration, the chlorophyll content, membrane permeability, SOD and CAT activities, and the contents of the three osmoregulatory substances under moderate drought began to recover. However, Fv, Fv/Fm, malondialdehyde, and POD activity did not recover under severe drought. These results illustrated that drought tolerance of A. halodendron resulted from increased enzyme (POD and CAT) activities and accumulation of osmoregulatory substances.

Vibrio harveyi is a Gram-negative bacterium that occurs widely in the ocean and a kind of pathogenic bacteria associated with vibriosis in grouper. We investigated whether the VscCD protein of the type Ⅲ secretion system (T3SS) was important for pathogenicity of V. harveyi. Mutations to the vscC and vscD genes (ΔvscCD) and complementation of the ΔvscCD mutant (C-ΔvscCD) were created. Moreover, the biological characteristics of the wild-type (WT) and mutant strains of V. harveyi 345 were compared. The results showed that deletion of the vscCD genes had no effect on bacterial growth, swimming/swarming ability, secretion of extracellular protease, or biofilm formation. However, as compared with the V. harveyi 345: pMMB207 (WT+) and complementary (C-ΔvscCD) strains, the ΔvscCD: pMMB207 (ΔvscCD+) mutant displayed decreased resistance to acid stress, H2O2, and antibiotics. In addition, infection of the pearl gentian grouper (♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatu) showed that as compared with the WT+ and C-ΔvscCD strains, the ΔvscCD+ strain significantly reduced cumulative mortality of the host. The colonization ability of the ΔvscCD+ mutant in the spleen and liver tissues of the pearl gentian grouper was significantly lower than that of the WT+ and C-ΔvscCD strains. In the early stage of infection with the ΔvscCD+ strain, the expression levels of IL-1β, IL-16, TLR3, TNF-α, MHC-Iα, and CD8α were up-regulated to varying degrees. As compared with the WT+ and C-ΔvscCD strains, luxR expression was significantly up-regulated in the ΔvscCD+ strain, while the expression of vcrH and vp1668 was significantly down-regulated. As an important component of the T3SS, VscCD seemed to play a significant role in the pathogenesis of V. harveyi.

Vibrio harveyi is an opportunistic Gram-negative pathogen that threatens future development of global aquaculture as well as human health. In this study, to gain insight into virulence regulation of cqsA in V. harveyi, a ΔcqsA mutant strain and complementation of the ΔcqsA mutant (C-cqsA) were constructed and phenotypically characterized. Deletion of cqsA led to enhanced mobility, iron absorption, resistance to H2O2, and biofilm formation ability, and reduced the ability to secrete extracellular proteases. In addition, pearl gentian grouper (♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatu) challege experiment was conducted to observe the changes in virulence at the absence of cqsA in V. harveyi. The results showed that the cumulative mortalities of the pearl gentian grouper challenged with the ΔcqsA+ mutant by intraperitoneal injection reached 91.67%, which was significantly higher than that of wild-type (WT+) (41.67%) and C-cqsA (41.67%) strains. Deletion of cqsA also resulted in a significant increase in the ability of V. harveyi to colonize the spleen and liver of the pearl gentian grouper simultaneously. Meanwhile, the early expression levels of immune-related genes of the pearl gentian grouper in the ΔcqsA+ mutant group, including TNF-α, IL-1β, MHC-Iα, IL-16, and IgM were up-regulated post-challenge, indicating that the ΔcqsA+ mutant may hijack the immune signaling pathway and cause early overexpression of some host immune-related genes. The expression levels of the V. harveyi virulence-associated genes flaA, flaC, fliA, fliS, cheR, lafA, aphA, and fur were up-regulated, while vhh and hapR were down-regulated. Collectively, these findings point to broad regulatory functions of cqsA in V. harveyi cells, which likely underlie an important role in pathogenicity.

A fusion peptide mimicking a part of the sequence of HIV-1 envelope glycoprotein with an additional cysteine at its C-terminus (FP8: AVGIGAVFC) was conjugated to a carrier protein through a linker for development of an HIV-1 vaccine. Since this fusion peptide is very hydrophobic with poor solubility and can self-dimerize via a disulfide bond, co-existence of monomeric and dimeric forms presented a major challenge for residual unconjugated FP8 quantification. A reversed-phase liquid chromatography (RPLC) with UV detection was developed to monitor residual FP8 using an experimental correction factor of 0.85 for UV peak area measurement between FP8 dimer and monomer. Therefore, both forms of unconjugated residual FP8 can be measured based on a single FP8 monomer reference curve. Overall, this study demonstrated that the current purification process can remove free residual FP8 to a low level, < 20 μg/mL, which showed negligible impact (< 10%) for the conjugated FP8 ratio measurement using another method, amino acid analysis.

Mathematical model of grain drying process is the grain drying machine design, the drying operation automatic control and the optimization of the important basis of drying technology. Cross flow drying is one of the forms of grain drying has been widely applied at present, this article is mainly to Page model is applied to the continuous grain in cross flow drying, and briefly introduces the model predictive control method and its application in the research and application of continuous cross-flow grain drying machine, so as to provide reference for similar research in China.

In order to improve the grain drying quality and automation level, combined with the structural characteristics of the cross-flow circulation grain dryer designed and developed by us, the temperature, moisture, and other parameters measuring sensors were placed on the dryer, to achieve online automatic detection of process parameters during the grain drying process. A drying model predictive control system was set up. A grain dry predictive control model at constant velocity and variable temperature was established, in which the entire process was dried at constant velocity (i.e., precipitation rate per hour is a constant) and variable temperature. Combining PC with PLC, and based on LabVIEW, a system control platform was designed.

In the process of drying, uneven drying rate will lead to the decline of grain quality, including the increase of crackle ratio, the destruction of the edible quality. In this paper, based on PAGE model the numerical simulation method suitable for circulated rice drying process of constant rate was developed and circulated rice drying process of constant rate was built. The simulation software of circulated rice drying process of constant rate was developed by MATLAB graphical interface language. Based on software setting of parameters including initial moisture, drying rate, hot air temperature, ambient temperature and ambient humidity, the simulation experiment of circulated rice drying process of constant rate could be conducted, the curves of grain moisture, grain temperature and drying rate could be drawn. The simulation experiment of rice circulation drying of constant rate was conducted, and the simulation results could served as the application of constant drying rate circulation drying.

Producing the grain with equilibrium moisture content is an important process control objective. However, achieving this objective can be very difficult in grain drying process because of its multi-variables, nonlinearity and long delay. In this paper, a control approach based on principal component analysis (PCA) is presented to achieve this objective. A PCA model which incorporates time lagged variables is used, and the control objective is expressed in the score space of this PCA model. A controller is designed in the model predictive control framework, and it is used to control the equivalent score space representation of the process. The score predictive model for the model predictive control algorithm is built using neural network partial least squares (NNPLS). The process control system with NNPLS was tested on a commercial mixed-flow dryer and showed excellent accuracy and stability.

Aiming at the block-based fusion methods for multi-focus images, such key problems like finding a suitable block size and overcoming the blocking-artifact often occurs. To address them, we present an intelligent fusion method using particle swarm optimization (PSO) algorithm, which is guided by a structural similarity (SSIM) criterion. In this method, PSO is to fast search for an appropriate block size, while the SSIM is employed as the fitness function in PSO, in order to evaluate the blocking-artifact, thus enabling this method to have a significant improvement in fusion performance. Experimental results show that the proposed method performs better than some classical methods, such as a block-based method similar with ours in fusion rule and multiresolution-based method. Besides, our method preserves more details than others in fused image.

A mathematical modeling of thin-layer drying of jujubes in a convective dryer was established under controlled conditions of temperature and velocity. The drying process took place both in the accelerating rate and falling rate period. We observed that higher temperature reduced the drying time, indicating higher drying rates of jujubes. The experimental drying data of jujubes were used to fit ten different thin-layer models, then drying rate constants and coefficients of models tested were determined by nonlinear regression analysis using the Statistical Computer Program. As for all the drying models, the Weibull distribution model was superior and best predicted the experimental values. Therefore, this model can be used to facilitate dryer design and promote efficient dryer operation by simulation and optimization of the drying processes. The volumetric shrinkable coefficient of jujubes decreased as the drying air temperature increased.