Pathogenicity of Streptococcus iniae causing mass mortalities of yellow catfish (Tachysurus fulvidraco) and its induced host immune response

The outbreak of mass mortality occurred in Tachysurus fulvidraco farm in Hubei province of China. The pathogenic strain of Streptococcus iniae (termed 2022SI08) was isolated and identified from diseased T. fulvidraco, based on morphological, physiological, and biochemical characteristics, as well as 16S rRNA gene sequence and phylogenetic analysis. Further, the whole genome of isolate S. iniae was sequenced and predicted to contain one single circular chromosome of 1,776,777 bp with a GC content of 37.14%. The genomic sequence analysis showed that 2022SI08 was positive for 204 virulent and 127 antibiotic resistant genes. The experimental challenge demonstrated the high pathogenicity of the retrieved isolate of S. iniae, with a median lethal dosage (LD50) 9.53 × 105 CFU/g. Histopathological examination indicated that the 2022SI08 strain could induce extensive tissue cell degeneration, necrosis, hemorrhage, and inflammation in the skin, gill, fin, spleen, liver, kidney, intestine, eye, and brain. Moreover, the innate immune enzyme activities in serum such as acid phosphatase and alkaline phosphatase were increased significantly at 24 and 48 h post infection (hpi) and then decreased at 168 hpi. The transcriptional profile of immune associated gene in T. fulvidraco following bacterial infection was detected at each point of time, and the results revealed clear transcriptional activation of those genes, which proving their reacting and regulatory role during the response of the host against S. iniae infection. The results revealed that S. iniae was an etiological agent in the mass mortalities of T. fulvidraco and this research will be conducive for increasing our understanding on pathogenesis and host defensive system in S. iniae invasion

Chromosome-level genome assembly of the largefin longbarbel catfish (Hemibagrus macropterus)

The largefin longbarbel catfish, Hemibagrus macropterus, is an economically important fish species in southwestern China, with males growing faster than females. This study presents a high-quality chromosome-level genome assembly of the largefin longbarbel catfish, generated by integrating Illumina short reads, PacBio HiFi long reads, and Hi-C data. The assembled genome size was 858.5 Mb, with a contig and scaffold N50 of 5.8 Mb and 28.4 Mb, respectively. A total of 656 contigs were successfully anchored to 30 pseudochromosomes with a BUSCO score of 97.7%, consistent with the number of chromosomes analyzed by karyotype. The genome contained 29.5% repeat sequences, and a predicted total of 26,613 protein-coding genes, of which 25,769 (96.8%) were functionally annotated in different databases. Evolutionary analysis showed that H. macropterus was most closely related to H. wyckioides, with a divergence time of approximately 16.3 million years. Chromosomal syntenic relationships among H. macropterus, H. wyckioides, and Pelteobagrus fulvidraco revealed a one-to-one relationship for most chromosomes, except for break, fission, and inversion of some chromosomes. The first high-quality reference genome will not only provide a valuable genetic resource for the study of sex determination mechanisms and genetic breeding of largefin longbarbel catfish, but also contribute to comparative analyses of genome and chromosome evolution within Siluriformes

Streptococcal Toxic Shock Syndrome Caused by Streptococcus suis Serotype 2

BACKGROUND: Streptococcus suis serotype 2 ( S. suis 2, SS2) is a major zoonotic pathogen that causes only sporadic cases of meningitis and sepsis in humans. Most if not all cases of Streptococcal toxic shock syndrome (STSS) that have been well-documented to date were associated with the non-SS2 group A streptococcus (GAS). However, a recent large-scale outbreak of SS2 in Sichuan Province, China, appeared to be caused by more invasive deep-tissue infection with STSS, characterized by acute high fever, vascular collapse, hypotension, shock, and multiple organ failure. METHODS AND FINDINGS: We investigated this outbreak of SS2 infections in both human and pigs, which took place from July to August, 2005, through clinical observation and laboratory experiments. Clinical and pathological characterization of the human patients revealed the hallmarks of typical STSS, which to date had only been associated with GAS infection. Retrospectively, we found that this outbreak was very similar to an earlier outbreak in Jiangsu Province, China, in 1998. We isolated and analyzed 37 bacterial strains from human specimens and eight from pig specimens of the recent outbreak, as well as three human isolates and two pig isolates from the 1998 outbreak we had kept in our laboratory. The bacterial isolates were examined using light microscopy observation, pig infection experiments, multiplex-PCR assay, as well as restriction fragment length polymorphisms (RFLP) and multiple sequence alignment analyses. Multiple lines of evidence confirmed that highly virulent strains of SS2 were the causative agents of both outbreaks. CONCLUSIONS: We report, to our knowledge for the first time, two outbreaks of STSS caused by SS2, a non-GAS streptococcus. The 2005 outbreak was associated with 38 deaths out of 204 documented human cases; the 1998 outbreak with 14 deaths out of 25 reported human cases. Most of the fatal cases were characterized by STSS; some of them by meningitis or severe septicemia. The molecular mechanisms underlying these human STSS outbreaks in human beings remain unclear and an objective for further study

Modélisation et recalage d'images protéomiques

L objectif de cette thèse est de développer des méthodes de traitement destinées aux images de gel d électrophorèse bidimensionnelle (2DGE). Nous abordons plus particulièrement un certain nombre de problèmes liés à la modélisation et au recalage des images 2DGE. Dans ce cadre, nous avons proposé une nouvelle approche de mise en correspondance pour les spots dans des images 2GDE. Cette approche s inspire du principe d attraction, et permet de détecter de manière précise un plus grand nombre de spots en correspondance. Elle est basée sur l exploitation simultanée de plusieurs types d information tels que la distance, l intensité et le pattern des spots. Les résultats obtenus sur des images aussi bien simulées que réelles montrent que l information de pattern de spots joue un rôle important dans la mise en correspondance des spots, et que son utilisation peut permettre d améliorer considérablement la précision de la mise en correspondance des spots, notamment pour des images 2DGE présentant des distorsions complexes et importantes. De même, une méthode de recalage non-linéaire d images 2DGE a été développée. Elle est basée sur le modèle de déformation TPS en intégrant le principe d attraction et le modèle de déformation spécifique à l électrophorèse bidimensionnelle. Dans cette méthode de recalage non-linéaire, une combinaison de la mise en correspondance précise des spots avec la transformation de TPS (ADIP-TPS) et la déformation sourire spéciale, a été identifiée comme étant en mesure de remplir les exigences de recalage d images 2DGE. Les résultats que nous avons obtenus confirment l intérêt d un choix judicieux de l information sur le pattern de spots et montrent l impact de la méthode proposée sur la qualité du recalage. En générale, cette méthode proposée améliore de manière significative la précision de recalage par rapport aux techniques traditionnelles, et suggère son utilisation prometteuse dans l analyse pratique des images 2DGE en protéomique.The objective of this thesis is to develop image modeling and processing methods for two-dimensional gel electrophoresis (2DGE) images. We study more particularly a number of problems related to the registration of 2DGE images. In this framework, we have proposed a novel approach of pairing or matching spots in 2DGE images. The approach is based on the principle of attraction, and allows accurately detecting more matching spots. It is based on the simultaneous exploitation of several types of information such as spot distance, spot intensity and spot pattern. The results on both simulated and real 2DGE images show that spot pattern information plays an important role in the process of spots matching and can greatly improve the accuracy of the matching, especially on images with complex distortions. Meanwhile, a non-linear image registration method for 2DGE images has been developed. This method is based on the TPS deformation model by integrating the principle of attraction and a deformation model specific to 2DGE. In this non-linear image registration method, the combination of accurate spot matching with the TPS transformation and special "smile" distortion has been shown to be able to meet the registration requirements of 2DGE images. The results we obtained confirm the interest of choosing spot pattern information, and show the impact of the proposed method on the quality of registration. In general, the proposed automatic method significantly improves the accuracy of registration compared to traditional registration techniques, and suggests its promising use in practical 2DGE image analysis in proteomics.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Dietary Epigallocatechin-3-Gallate (EGCG) Improves Nonspecific Immune Response of Chinese Rice Field Eel (Monopterus albus)

Epigallocatechin-3-gallate (EGCG) has been recognized as a potential additive for aquafeeds due to its beneficial biological functions. In order to evaluate the potential application of EGCG in Chinese rice field eel (Monopterus albus), six isonitrogenous and isolipidic diets containing 0, 25, 50, 100, 200, and 400 mg/kg EGCG were formulated and were fed to Monopterus albus (M. albus) for 9 weeks. The results showed that M. albus fed diets containing 0 and 100 mg/kg EGCG presented higher weight again and specific growth rate than the other groups. Fish fed with 25, 50, and 400 mg/kg EGCG displayed lower whole-body lipid content. Serum aspartate aminotransferase (AST) concentration significantly decreased in EGCG treated groups with the exception of 100 mg/kg group. Hepatic catalase (CAT) activity and glutathione (GSH) concentration decreased as EGCG level increased while malondialdehyde (MDA) concentration showed an opposite trend. EGCG supplementation resulted in a promoted lysozyme (LZM) activity and immunoglobulin M (IgM) level in the liver of M. albus. Furthermore, transcription of three immune related genes including major histocompatibility complex (mhc-2α), hepcidin, and interleukin-8 (il-8) mRNAs was upregulated by EGCG treatment; while transcription of interleukin-6 (il-6) and nuclear factor kappa-B (nf-kb) genes was downregulated. Results also showed a linear relation between EGCG inclusion level and parameters of AST, CAT, GSH, MDA, LZM, IgM, and immune-related genes transcriptions. In summary, it could be suggested that EGCG supplementation enhanced the nonspecific immune response of the Chinese rice field eel. Based on the broken-line regression analysis of IgM, the optimal dietary EGCG supplementation for M. albus was estimated to be 109.81 mg/kg

Characterization of Biochar Derived from Pineapple Peel Waste and Its Application for Sorption of Oxytetracycline from Aqueous Solution

Physicochemical characteristics of biochar and its sorption potential for oxytetracycline (OTC) were investigated. Biochars from pineapple peel waste were produced via pyrolysis under oxygen-depleted conditions at 350 °C (BL350), 500 °C (BL500), and 650 °C (BL650), as well as the characteristics and polycyclic aromatic hydrocarbons contents of the samples were compared. The sorption kinetics of OTC onto the biochars was completed in three stages, i.e., a fast stage, a slow stage, and an equilibrium stage after 24 h. The kinetics data were perfectly fitted by the pseudo-second-order model with high correlation coefficients (R2 > 0.999). All of the sorption isotherms were nonlinear and well described by the Langmuir model. The Langmuir maximum sorption capacity (qmax) increased in the order of BL650 > BL500 > BL350. The thermodynamic parameters revealed that the sorption of OTC onto the biochars was spontaneous and endothermic. Fourier transform infrared spectroscopy (FTIR) of the biochars before and after sorption of OTC confirmed that the H-bonding interaction was the dominant sorption mechanism. The results demonstrated that biochars obtained from inexpensive and renewable materials could be utilized as a highly effective and environmentally friendly adsorbent for removing organic contaminants from wastewater

Summary of simple sequence repeat (SSR) types in the Chinese sturgeon transcriptome.

<p>^aNumber of SSRs detected in unigenes</p><p>^bRelative percent of SSRs with different repeat motifs among the total SSRs</p><p>Summary of simple sequence repeat (SSR) types in the Chinese sturgeon transcriptome.</p

Functional annotation of unigenes of the <i>Acipenser sinensis</i> transcriptome.

<p>Functional annotation of unigenes of the <i>Acipenser sinensis</i> transcriptome.</p

The distribution of transcripts between testis and ovary.

<p>(A) The numbers of all transcripts present in the testis, ovary, or both. (B) The distribution of transcripts with potential function in sexual development in testis and ovary.</p

Real-time PCR confirmation of the relative expression of genes showing differential expression between the two gonad types.

<p>^a The relative-fold expression determined by Illumina transcriptome analysis.</p><p>^b The relative-fold expression validated by qRT-PCR.</p><p>O/T: The relative transcription level of genes in ovary compared to that in testis. O, Ovary; T, Testis.</p><p>Real-time PCR confirmation of the relative expression of genes showing differential expression between the two gonad types.</p