Description of Fuscovulum ytuae sp. nov, a facultative autotroph isolated from the intertidalite of Yangma island, China.

In this study, we reported a Gram-stain-negative, ovoid to rod-shaped, atrichous, and facultative anaerobe bacteria strain named YMD61T, which was isolated from the intertidal sediment of Yangma island, China. Growth of strain YMD61T occurred at 10.0-45.0 °C (optimum, 30.0 °C), pH 7.0-10.0 (optimum, 8.0) and with 0-3.0% (w/v) NaCl (optimum, 2.0%). Phylogenetic tree analysis based on 16 S rRNA gene or genomic sequence indicated that strain YMD61T belonged to the genus Fuscovulum and was closely related to Fuscovulum blasticum ATCC 33,485T (96.6% sequence similarity). Genomic analysis indicated that strain YMD61T contains a circular chromosome of 3,895,730 bp with DNA G + C content of 63.3%. The genomic functional analysis indicated that strain YMD61T is a novel sulfur-metabolizing bacteria, which is capable of fixing carbon through an autotrophic pathway by integrating the processes of photosynthesis and sulfur oxidation. The predominant respiratory quinone of YMD61T was ubiquinone-10 (Q-10). The polar lipids of YMD61T contained phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, five unidentified lipids, unidentified aminolipid and unidentified aminophospholipid. The major fatty acids of strain YMD61T contained C18:1ω7c 11-methyl and summed feature 8 (C18:1 ω 7c or/and C18:1 ω 6c). Phylogenetic, physiological, biochemical and morphological analyses suggested that strain YMD61T represents a novel species of the genus Fuscovulum, and the name Fuscovulum ytuae sp. nov. is proposed. The type strain is YMD61T (= MCCC 1K08483T = KCTC 43,537T).

Fatty acid esters of hydroxy fatty acids: A potential treatment for obesity-related diseases.

Obesity, a burgeoning worldwide health system challenge, is associated with multiple chronic diseases, including diabetes and chronic inflammation. Fatty acid esters of hydroxy fatty acids (FAHFAs) are newly identified lipids with mitigating and anti-inflammatory effects in diabetes. Increasing work has shown that FAHFAs exert antioxidant activity and enhance autophagy in neuronal cells and cardiomyocytes. We systematically summarized the biological activities of FAHFAs, including their regulatory effects on diabetes and inflammation, antioxidant activity, and autophagy augmentation. Notably, the structure-activity relationships and potential biosynthesis of FAHFAs are thoroughly discussed. FAHFAs also showed potential roles as diagnostic biomarkers. FAHFAs are a class of resources with promising applications in the biomedical field that require in-depth research and hotspot development, as their structure has not been fully resolved and their biological activity has not been fully revealed.

Tetraspanin CD53 regulates peripheral blood leucocytes vitality and pathogen infection in turbot (Scophthalmus maximus).

Cluster of differentiation 53 (CD53) also known as OX44 or tetraspanin 25 (TSPAN25) is a glycoprotein belonging to the tetraspanin family. Members of the tetraspanin family are characterized by four transmembrane domains, including intracellular N- and C-termini, and small and large extracellular domains. Currently, the function of CD53 in teleost is not well understood. In this study, we identified a CD53 (named SmCD53) from turbot (Scophthalmus maximus) and examined its expression and biological activity. SmCD53 contained 231 amino acid residues and was predicted to be a tetraspanin with small and large extracellular domains. SmCD53 expression was observed in different tissues, particularly in immune-related organs. Experimental infection with bacterial or viral pathogen significantly up-regulated SmCD53 expression in a time-dependent manner. Immunofluorescence microscopy analysis showed that SmCD53 was localized on the surface of PBL and was recognized by antibody against its large extracellular domain. Ligation of SmCD53 onto PBLs with antibodies suppressed the respiratory burst activity, inflammatory reaction, and enhanced cell viability. SmCD53 knockdown significantly enhanced bacterial dissemination and proliferation in turbot. Overall, these results underscore the importance of CD53 in the maintenance of the function and homeostasis of the immune system.

CsIL-20, a tongue sole interleukin-20, negatively mediates leucocyte activity and antibacterial defense.

Interleukin-20 (IL-20), as an essential member of IL-10 family, plays vital roles in mammalian immunological response such as antimicrobial, inflammation, hematopoiesis, and immune diseases. In teleost, the study about immune antimicrobial function of IL-20 is largely scarce. In this article, we revealed the expression profiles and the immunological functions of the IL-20 (CsIL-20) in tongue sole Cynoglossus semilaevis. CsIL-20 is composed of 183 amino acid residues, with seven cysteine residues and a typical IL-10 domain which comprises six α-helices and two ß-sheets, and shares 34.4-71.2 % identities with other teleost IL-20. CsIL-20 was constitutively expressed in a variety of tissues and regulated by bacterial invasion, and the recombinant CsIL-20 (rCsIL-20) could bind to different bacteria. In vitro rCsIL-20 could interact with the membrane of peripheral blood leukocytes (PBLs), leading to the attenuation of reactive oxygen species (ROS) production and acid phosphatase activity in PBLs. In line with In vitro results, In vivo rCsIL-20 could obviously suppressed the host immune against bacterial infection. Furthermore, knockdown of CsIL-20 in vivo could markedly enhance the host antibacterial immunity. Collectively, these observations offer new insights into the negative effect of CsIL-20 on antibacterial immunity.

Nutritional Component Analyses in Different Varieties of Actinidia eriantha Kiwifruit by Transcriptomic and Metabolomic Approaches.

Actinidia eriantha is a unique germplasm resource for kiwifruit breeding. Genetic diversity and nutrient content need to be evaluated prior to breeding. In this study, we looked at the metabolites of three elite A. eriantha varieties (MM-11, MM-13 and MM-16) selected from natural individuals by using a UPLC-MS/MS-based metabolomics approach and transcriptome, with a total of 417 metabolites identified. The biosynthesis and metabolism of phenolic acid, flavonoids, sugars, organic acid and AsA in A. eriantha fruit were further analyzed. The phenolic compounds accounted for 32.37% of the total metabolites, including 48 phenolic acids, 60 flavonoids, 7 tannins and 20 lignans and coumarins. Correlation analysis of metabolites and transcripts showed PAL (DTZ79_15g06470), 4CL (DTZ79_26g05660 and DTZ79_29g0271), CAD (DTZ79_06g11810), COMT (DTZ79_14g02670) and FLS (DTZ79_23g14660) correlated with polyphenols. There are twenty-three metabolites belonging to sugars, the majority being sucrose, glucose arabinose and melibiose. The starch biosynthesis-related genes (AeglgC, AeglgA and AeGEB1) were expressed at lower levels compared with metabolism-related genes (AeamyA and AeamyB) in three mature fruits of three varieties, indicating that starch was converted to soluble sugar during fruit maturation, and the expression level of SUS (DTZ79_23g00730) and TPS (DTZ79_18g05470) was correlated with trehalose 6-phosphate. The main organic acids in A. eriantha fruit are citric acid, quinic acid, succinic acid and D-xylonic acid. Correlation analysis of metabolites and transcripts showed ACO (DTZ79_17g07470) was highly correlated with citric acid, CS (DTZ79_17g00890) with oxaloacetic acid, and MDH1 (DTZ79_23g14440) with malic acid. Based on the gene expression, the metabolism of AsA acid was primarily through the L-galactose pathway, and the expression level of GMP (DTZ79_24g08440) and MDHAR (DTZ79_27g01630) highly correlated with L-Ascorbic acid. Our study provides additional evidence for the correlation between the genes and metabolites involved in phenolic acid, flavonoids, sugars, organic acid and AsA synthesis and will help to accelerate the kiwifruit molecular breeding approaches.

Draft genome sequence data of Urechis unicinctus, a marine echiuroid worm.

Urechis unicinctus is mainly distributed in Japan, north Korea and the Yellow Sea and the coast of Bohai Bay in China, and its nutrition is rich. The body of Urechis unicinctus contains many types of bioactive polypeptides, such as plasmin and tachykinin, which hold high economic and medicinal values. Therefore, the study of Urechis unicinctus has great significance. But the genome of Urechis unicinctus remains unavailable till now. To further understand the evolution of Urechis unicinctus and determine more effective application of it, we assembled the first draft genome sequence and the assembly of Urechis unicinctus. The dataset can be assessed from the BioProject at NCBI (https://www.ncbi.nlm.nih.gov/bioproject/?term=Urechisunicinctus).

Dataset of the transcriptomes of Urechis unicinctus to identify differentially expressed genes (DEGs) under different temperature and exposure to open air.

Urechis unicinctus has a wide range of bioactive polypeptides with high edible, economic and medicinal values. As the key technical breakthrough, the artificial breeding is imperative. However, the seedling transport becomes a primary matter, which indicates the indispensability of realizing how Urechis unicinctus responses to various situations. We compared transcriptome of Urechis unicinctus under the dry and ultraviolet irradiation treatment and different temperature. The dataset of the organism in response to water-temperature variety was provided by using the Illumina Hiseq X Ten system, which will be helpful to understand the adaptation of Urechis unicinctus to changing temperature (low, high and room temperature) and open air (ultraviolet and desiccation). The assembly of the transcriptomes was carried out using the isoform sequencing (Iso-seq) method. The functions of expressed genes were annotated and categorized, while the DEGs were presented.

Phycocyanin attenuates pulmonary fibrosis via the TLR2-MyD88-NF-κB signaling pathway.

Our aim was to investigate the effects of phycocyanin (PC) on bleomycin (BLM)-induced pulmonary fibrosis (PF). In this study, C57 BL/6 wild-type (WT) mice and toll-like receptor (TLR) 2 deficient mice were treated with PC for 28 days following BLM exposure. Serum and lung tissues were collected on days 3, 7 and 28. Data shows PC significantly decreased the levels of hydroxyproline (HYP), vimentin, surfactant-associated protein C (SP-C), fibroblast specific protein-1 (S100A4) and α-smooth muscle actin (α-SMA) but dramatically increased E-cadherin and podoplanin (PDPN) expression on day 28. Moreover, PC greatly decreased the levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and myeloperoxidase (MPO) at the earlier time. Reduced expression of key genes in the TLR2 pathway was also detected. Compared with WT mice, TLR2-deficient mice exhibited less injury, and the protective effect of PC was partly diminished in this background. These data indicate the anti-fibrotic effects of PC may be mediated by reducing W/D ratio, MPO, IL-6, TNF-α, protecting type I alveolar epithelial cells, inhibiting fibroblast proliferation, attenuating epithelial-mesenchymal transitions (EMT) and reducing oxidative stress. The TLR2-MyD88-NF-κB pathway plays an important role in PC-mediated reduction in pulmonary fibrosis.

Differences between flocculating yeast and regular industrial yeast in transcription and metabolite profiling during ethanol fermentation.

Objectives: To improve ethanolic fermentation performance of self-flocculating yeast, difference between a flocculating yeast strain and a regular industrial yeast strain was analyzed by transcriptional and metabolic approaches. Results: The number of down-regulated (industrial yeast YIC10 vs. flocculating yeast GIM2.71) and up-regulated genes were 4503 and 228, respectively. It is the economic regulation for YIC10 that non-essential genes were down-regulated, and cells put more "energy" into growth and ethanol production. Hexose transport and phosphorylation were not the limiting-steps in ethanol fermentation for GIM2.71 compared to YIC10, whereas the reaction of 1,3-disphosphoglycerate to 3-phosphoglycerate, the decarboxylation of pyruvate to acetaldehyde and its subsequent reduction to ethanol were the most limiting steps. GIM2.71 had stronger stress response than non-flocculating yeast and much more carbohydrate was distributed to other bypass, such as glycerol, acetate and trehalose synthesis. Conclusions: Differences between flocculating yeast and regular industrial yeast in transcription and metabolite profiling will provide clues for improving the fermentation performance of GIM2.71.

Soil heavy metal pollution and risk assessment in Shenyang industrial district, Northeast China.

To investigate the soil heavy metal pollution characteristics and ecological risk factors, 42 samples and six typical soil profiles were collected from the Shenyang industrial district in northeast China and were analyzed for contents of titanium (Ti), copper (Cu), lead (Pb), zinc (Zn), cobalt (Co), nickel (Ni), chromium (Cr) and arsenic (As). Through statistical analysis, it was found that the mean concentrations were higher than their background values (Ti = 4.77>3.8g/kg, Cu = 33.75>22.6 mg/kg, Pb = 45.95>26 mg/kg, Zn = 81.54>74.2 mg/kg, Co = 12.91>12.7 mg/kg, Ni = 32.26>26.9 mg/kg, Cr = 83.36>61 mg/kg and As = 13.69>11.2 mg/kg) but did not exceed their corresponding pollution limits for the Chinese Environmental Quality Standard for Soils (State Environmental Protection Administration of China, 1995). There were contamination hotspots that may be caused by human activities such as smelting plants and sewage irrigation. The Enrichment Factor and Ecological Risk Index were used to identify the anthropogenic contamination and ecological risks of heavy metals. Soil in the study area could be considered lightly or partially polluted by heavy metals. According to clustering analysis, distinct groups of heavy metals were discriminated between natural or anthropogenic sources.

Evaluation of soil contamination indices in a mining area of Jiangxi, China.

There is currently a wide variety of methods used to evaluate soil contamination. We present a discussion of the advantages and limitations of different soil contamination assessment methods. In this study, we analyzed seven trace elements (As, Cd, Cr, Cu, Hg, Pb, and Zn) that are indicators of soil contamination in Dexing, a city in China that is famous for its vast nonferrous mineral resources in China, using enrichment factor (EF), geoaccumulation index (Igeo), pollution index (PI), and principal component analysis (PCA). The three contamination indices and PCA were then mapped to understand the status and trends of soil contamination in this region. The entire study area is strongly enriched in Cd, Cu, Pb, and Zn, especially in areas near mine sites. As and Hg were also present in high concentrations in urban areas. Results indicated that Cr in this area originated from both anthropogenic and natural sources. PCA combined with Geographic Information System (GIS) was successfully used to discriminate between natural and anthropogenic trace metals.

Soil and soil environmental quality monitoring in China: a review.

Over the past few decades, numerous concerns have been raised in China over the issue of environmental sustainability. Various soil survey and monitoring programs have been carried out in China to study soil quality, and to provide a scientific basis for environment policy making. This paper provides an overview of past and current soil quality surveys and monitoring activities in China. This paper includes a summary of concerns over background concentrations of elements in soil, and soil environmental standards and guidelines in China. Levels of pollution in urban soil, agricultural soil, and soil in mining and smelting areas were compared using the concentrations and pollution indexes. In addition to soil surveys, soil monitoring is essential to study the data and to examine the effects of contaminants in soils. However, the current soil quality monitoring system was insufficient to accurately determine the soil quality status of soils across China. For accurate soil monitoring in China, it will be necessary to set up routine monitoring systems at various scales (national, provincial, and local scales), taking into consideration monitoring indicators and quality assurance. This is currently an important priority for the environmental protection administration of China.

Induction of oxidative stress and related transcriptional effects of perfluorononanoic acid using an in vivo assessment.

Perfluorononanoic acid (PFNA) is an organic pollutant ubiquitous in the environment. However, the potential toxicity of PFNA remains largely unknown in teleost fish. This study defined the oxidative stress and related transcriptional effects of PFNA at various concentrations on zebrafish larvae. Activities of superoxide dismutase were induced in PFNA-treated groups but attenuated with exposure to higher concentration. Catalase activity and lipid peroxidation were significantly inhibited or increased at the highest concentration, respectively. To test the apoptotic pathway, several genes related to cell apoptosis were examined using real-time PCR. The expression of p53, apoptosis-inducing factor (AIF) and c-Jun NH (2)-terminal kinase (JNK) was partially increased, while Bcl-2, an anti-apoptotic gene, was reduced, with no significant effects on Bax and caspase-3 during the exposure period. The effect of PFNA on lipid ß-oxidation system was investigated by examining the activity of peroxisome fatty acyl-COA oxidase (ACOX) and the expression of peroxisome proliferating activating receptors (PPARs). ACOX activity was moderately elevated with marginal significance and was not a significant consequence of PPARα and PPARγ expression. The overall results suggest that turbulence of oxidative stress and apoptotic pathway is involved in PFNA-induced toxicity in zebrafish larvae, and the gene expression patterns are able to reveal some potential mechanisms of developmental toxicity.

Hainanenins: a novel family of antimicrobial peptides with strong activity from Hainan cascade-frog, Amolops hainanensis.

Antimicrobial peptides (AMPs) secreted by amphibian skin represent an important innate immune defense strategy. There are more than 340 species in the family of Ranidae worldwidely, and from which nearly 100 families of AMPs comprising between 8 and 48 amino acid (aa) residues have been characterized. In current work, two novel AMPs were purified from the skin secretion of Hainan cascade-frog, Amolops hainanensis, and 31 cDNA sequences encoding 10 novel AMPs belonging to 4 families were cloned from the constructed skin cDNA library of A. hainanensis. Among these 10 AMPs, 5 peptides represent the prototypes of a novel amphibian AMP family. According to the generic name of the species of origin, they were designated as hainanenin-1-5. Each of them consists of 21 aa residues with a C-terminal disulphide loop of 7 residues between Cys(15) and Cys(21). Two of them (hainanenin-1 and 5) were then synthesized and their in vitro activities were screened, including antimicrobial, hemolytic and antioxidant activities. The results showed that hainanenin-1 and 5 possessed strong and broad-spectrum antimicrobial activities against Gram-positive, Gram-negative bacteria and fungi, including a large number of clinically isolated drug-resistant pathogenic microorganisms, and slight antioxidant activity. Undesirably, hainanenin-1 and 5 exhibited strong hemolytic activity on human erythrocytes. The discovery of hainanenins and their great antimicrobial potency provides new templates for anti-infective agent design.

Dissection and localization of the immunostimulating domain of Edwardsiella tarda FliC.

Bacterial flagellin is known to induce potent immune response in vertebrate systems via the toll-like receptor (TLR) 5. As a result, flagellin has been studied extensively as a vaccine adjuvant. In a previous study, we examined the vaccine and adjuvant potentials of the flagellin (FliC) of the fish pathogen Edwardsiella tarda. We found that E. tarda FliC induced low protective immunity by itself but could function as a molecular adjuvant and potentiate the specific immune response induced by the E. tarda antigen Eta6. Since FliC is a large protein and organized into distinct structural domains, we wondered whether the immunostimulating effect observed with the full-length protein could be localized to a certain region. To investigate this question, we in the present study dissected the FliC protein into several segments according to its structural features: (i) N163, which consists of the conserved N-terminal 163 residues of FliC; (ii) M160, which consists of the variable middle 160 residues; (iii) C94, which consists of the conserved C-terminal 94 residues; (iv) NC257, which is an artificial fusion of N163 and C94. To examine the adjuvanticity of the FliC fragments, DNA vaccine plasmids expressing FliC fragments in fusion with Eta6 were constructed and used to immunize Japanese flounder. The results showed that N163 produced the best adjuvant effect, which, in respect to improvement in the relative percent survival of the vaccinated fish, was comparable to that of the full-length FliC. None of the other FliC fragments exhibited apparent immunopotentiating effect. Further analysis showed that N163 enhanced the production of serum specific antibodies and, like full-length FliC, significantly upregulated the expression of the genes that are possibly involved in innate and adaptive immunity. These results indicate that N163 is the immunodominant region of FliC and suggest that E. tarda FliC may induce immune responses in Japanese flounder via mechanisms alternative to that involving TLR5.

Identification and immunoprotective analysis of a Streptococcus iniae subunit vaccine candidate.

Streptococcus iniae is a Gram-positive bacterium and a severe aquaculture pathogen that can infect a wide range of farmed fish species. In the summer of 2006, an epidemic broke out in a fish farm in north China, and examination of moribund fish (Japanese flounder) identified the possible etiological agent of the outbreak as a strain named SF1, which exhibited apparent virulence in a Japanese flounder infection model and conforms to the description of S. iniae by 16S rRNA sequence analysis and API 20 Strep test. Biochemical and random amplified polymorphic DNA analyses indicated that SF1 is of the serotype I. A putative iron-binding protein, Sip11, was identified from SF1 using a previously established molecular trap that selects exported proteins. Recombinant Sip11 was purified from Escherichia coli and found to be protective against SF1 infection when used as an injection vaccine administered intraperitoneally into Japanese flounder. To improve the vaccine potential of Sip11, an E. coli strain was constructed, which expresses and secrets recombinant Sip11 covalently linked to a carrier protein in the form of a chimera. Vaccination of Japanese flounder with live Sip11-secreting E. coli afforded complete protection upon the fish following lethal SF1 challenge. These results indicate that Sip11, especially when delivered by a live bacterial carrier, is an effective vaccine candidate against SF1 infection.

Analysis of Edwardsiella tarda DegP, a serine protease and a protective immunogen.

Edwardsiella tarda is a severe aquaculture pathogen with a broad host range that includes humans, animal, and fish. A gene (degP(Et)) encoding a DegP homologue was cloned from TX01, a pathogenic E. tarda strain isolated from diseased fish. DegP(Et) shares high sequence identities with the DegP proteins of several bacterial species. Functional analyses showed that degP(Et) could complement the temperature-sensitive phenotype of an Escherichia coli degP null mutant. Expression of degP(Et) in TX01 was modulated by growth phase and temperature, the latter possibly through the action of the sigma(E)-like factor. Overexpression of degP(Et) (i) enhanced the ability of TX01 to disseminate in fish blood at the advanced stage of infection, (ii) heightened the activity of type 2 autoinducer, and (iii) increased the expression of luxS and the genes encoding components of the virulence-associated type III secretion system. Recombinant DegP(Et) purified from E. coli was a serine protease that exhibited maximum activity at 40 degrees C and pH8.0. The proteolytic activity of recombinant DegP(Et) depended on the catalytic triad and the PDZ domains. Immunoprotective analyses showed that purified recombinant DegP(Et) was a protective immunogen that could induce the production of specific serum antibodies and elicit strong protective immunity in fish vaccinated with DegP(Et).

DNA adenine methylase is involved in the pathogenesis of Edwardsiella tarda.

Edwardsiella tarda is a serious aquaculture pathogen that can infect many cultured fish species. The aim of this study was to investigate the potential importance of DNA adenine methylase (Dam) in E. tarda pathogenesis. The E. tarda dam gene (dam(Et)) was cloned from a pathogenic strain, TXD1, isolated from diseased fish. Dam(Et) shares high (70.2%) sequence identity with the Dam proteins of Yersinia enterocolitica and several other bacterial species. Recombinant Dam(Et) is able to complement a dam-deficient Escherichia coli strain and methylate the genomic DNA. Attenuation of dam(Et) expression by antisense RNA interference had no apparent effect on the growth of TXD1, but caused significant attenuation of overall bacterial virulence and altered several stress responses including spontaneous mutation, recovering from UV radiation and H(2)O(2) exposure, binding to host mucus, and dissemination in host blood and liver. In addition, attenuation of dam(Et) expression increased luxS expression and AI-2 activities in E. tarda. These results indicate that Dam(Et) is a virulence determinant and plays a role in the pathogenesis of TXD1, and that temporal expression of dam(Et) is essential for optimal bacterial infection.

Comparative study of the effects of aluminum adjuvants and Freund's incomplete adjuvant on the immune response to an Edwardsiella tarda major antigen.

Edwardsiella tarda is a severe aquaculture pathogen that can infect many different fish species cultured worldwide. Et49 is a major E. tarda antigen with weak immunoprotective potential. In this study, using Et49 as an example vaccine, the adjuvanticity of Freund's incomplete adjuvant (FIA), aluminum hydroxide, and aluminum phosphate adjuvant were evaluated in a Japanese flounder model. The results showed that the presence of FIA, aluminum hydroxide, and aluminum phosphate adjuvant increased the relative percent of survival of Et49-vaccinated fish by 47%, 19%, and 35%, respectively. Fish vaccinated with FIA-adjuvanted Et49 exhibited longer persistence of vaccine at the injection site and more severe intra-abdominal lesions than fish vaccinated with aluminum-adjuvanted Et49. Both aluminum adjuvants and, to a lesser degree, FIA augmented the production of specific serum antibodies, which reached the highest levels at 6 and 7 weeks post-vaccination. Passive immunization of Japanese flounder with sera from fish vaccinated with aluminum- and FIA-adjuvanted Et49 induced no protection against lethal E. tarda challenge. Examination of the transcription profile of immune-related genes showed that vaccination with aluminum-adjuvanted Et49 significantly enhanced the expression of the genes that are associated mainly with humoral immunity, whereas vaccination with FIA-adjuvanted Et49 induced the expression of a much broader spectrum of genes that are likely to be involved in humoral and innate cellular immunity. These results provide new insights to the action mechanisms of FIA and aluminum adjuvants in Japanese flounder and may be useful for the selection of adjuvant for vaccine formulations intended for Japanese flounder.

Analysis of the vaccine potential of a laboratory Escherichia coli strain in a Japanese flounder model.

Escherichia coli DH5alpha is a genetically tailored laboratory strain that is commonly used for general cloning. In this study, the vaccine potential of DH5alpha was investigated. It was found that when used as a live vaccine, DH5alpha could afford effective protection upon Japanese flounder against Aeromonas hydrophila infection. Vaccination with purified outer membrane proteins and lipopolysaccharides of DH5alpha failed to induce protective immunity against A. hydrophila. Specific antibody production was observed in fish immunized with DH5alpha, which lasted at least 8 weeks and was enhanced by a booster injection during the vaccination process. Analysis of the transcription profiles of immune-related genes showed that vaccination with DH5alpha heightened the expression of the genes encoding factors that are likely involved in both specific and nonspecific immunities. Furthermore, compared to the control fish, fish vaccinated with DH5alpha/pAQ1, which is DH5alpha harboring the plasmid pAQ1 that expresses the coding element of a Vibrio harveyi antigen, exhibited significantly improved survival rates following V. harveyi and A. hydrophila challenges. These results demonstrate that DH5alpha possesses intrinsic immunoprotective potential against A. hydrophila. This property, together with the feature of cloning friendliness, should render DH5alpha useful in the construction of cross-protective vaccines.