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It is very important to monitor the infection of Mycoplasma ovipneumoniae as a potential threat to the sheep industry. Southern Xinjiang is a major sheep breeding base in China, however, there is no relevant information concerning the infection of the region’s ovine stock with this bacteria at present. This study aimed to address this knowledge gap.

Mycoplasma bovis is a major pathogen causing arthritis, respiratory disease and mastitis in cattle. A better understanding of its genetic features and evolution might represent evidences of surviving host environments. In this study, multiple factors influencing synonymous codon usage patterns in M. bovis (three strains’ genomes) were analyzed. The overall nucleotide content of genes in the M. bovis genome is AT-rich. Although the G and C contents at the third codon position of genes in the leading strand differ from those in the lagging strand (p<0.05), the 59 synonymous codon usage patterns of genes in the leading strand are highly similar to those in the lagging strand. The over-represented codons and the under-represented codons were identified. A comparison of the synonymous codon usage pattern of M. bovis and cattle (susceptible host) indicated the independent formation of synonymous codon usage of M. bovis. Principal component analysis revealed that (i) strand-specific mutational bias fails to affect the synonymous codon usage pattern in the leading and lagging strands, (ii) mutation pressure from nucleotide content plays a role in shaping the overall codon usage, and (iii) the major trend of synonymous codon usage has a significant correlation with the gene expression level that is estimated by the codon adaptation index. The plot of the effective number of codons against the G+C content at the third codon position also reveals that mutation pressure undoubtedly contributes to the synonymous codon usage pattern of M. bovis. Additionally, the formation of the overall codon usage is determined by certain evolutionary selections for gene function classification (30S protein, 50S protein, transposase, membrane protein, and lipoprotein) and translation elongation region of genes in M. bovis. The information could be helpful in further investigations of evolutionary mechanisms of the Mycoplasma family and heterologous expression of its functionally important proteins. [ABSTRACT FROM AUTHOR]

The article presents a study which identifies and isolates the Mycoplasma caprisolum subsp. capripneumoniae in goats in Gansu Sheng, China.

The article presents a study on the development of screening methods of bacterial virulence genes and the host-pathogen interaction.

The gut microbiota, a pivotal component of the intestinal mucosal barrier, is critical for host resistance to enteric pathogen infection. Here, we report a novel function of the potentially probiotic Lactococcus garvieae strain LG1 ( L. garvieae strain LG1) in maintaining intestinal mucosal barrier integrity and protecting against foodborne Clostridium perfringens ( C. perfringens ) infection. L. garvieae was isolated from the intestinal contents of Chinese Mongolian sheep (MS) and exhibited potential probiotic properties. In a C. perfringens enterocolitis model, L. garvieae- pretreated mice were less susceptible to C. perfringens infection compared with Phosphate buffered solution (PBS) - pretreated mice, which manifested as higher survival rates, lower pathogen loads, less weight loss, mild clinical symptoms and intestinal damage, and minor inflammation. Further mechanistic analysis showed that L. garvieae could ameliorate the disruption of intestinal permeability and maintain the integrity of the intestinal mucosal barrier by promoting the expression of tight junction proteins and mucoproteins. Moreover, L. garvieae was also able to facilitate antimicrobial peptide expression and ameliorate dysbiosis of the gut microbiota caused by C. perfringens . Together, these findings highlight the prospect of immunomodulatory potentially probiotic L. garvieae and might offer valuable strategies for prophylaxis and/or treatment of pathogenic C. perfringens mucosal infection., Importance: C. perfringens necrotic enteritis leads to losses of about US $2 billion to the poultry industry worldwide every year. Worse, US Centers for Disease Control and Prevention (CDC) has estimated that C. perfringens causes nearly 1 million foodborne illnesses in the United States annually. Nowadays, the treatment recommendation is a combination of a broad-spectrum synergistic penicillin with clindamycin or a carbapenem, despite growing scientific concern over antibiotic resistance. The global understanding of the gut microbiome for C. perfringens infection may provide important insights into the intervention. L. garvieae originated from Mongolian sheep intestine, exhibited potentially probiotic properties, and was able to limit C. perfringens enterocolitis and pathogenic colonization. Importantly, we found that L. garvieae limits C. perfringens invasion via improving intestinal mucosal barrier function. Also, L. garvieae alleviates C. perfringens -induced gut microbiota dysbiosis. It allowed us to convince that utilization of probiotics to promote protective immunity against pathogens infection is of pivotal importance., Competing Interests: The authors declare no conflict of interest.

Understanding the genetic mechanisms of phenotypic variation in hybrids between domestic animals and their wild relatives may aid germplasm innovation. Here, we report the high-quality genome assemblies of a male Pamir argali ( O ammon polii , 2 n = 56), a female Tibetan sheep ( O aries , 2 n = 54), and a male hybrid of Pamir argali and domestic sheep, and the high-throughput sequencing of 425 ovine animals, including the hybrids of argali and domestic sheep. We detected genomic synteny between Chromosome 2 of sheep and two acrocentric chromosomes of argali. We revealed consistent satellite repeats around the chromosome breakpoints, which could have resulted in chromosome fusion. We observed many more hybrids with karyotype 2 n = 54 than with 2 n = 55, which could be explained by the selfish centromeres, the possible decreased rate of normal/balanced sperm, and the increased incidence of early pregnancy loss in the aneuploid ewes or rams. We identified genes and variants associated with important morphological and production traits (e.g., body weight, cannon circumference, hip height, and tail length) that show significant variations. We revealed a strong selective signature at the mutation (c.334C > A, p.G112W) in TBXT and confirmed its association with tail length among sheep populations of wide geographic and genetic origins. We produced an intercross population of 110 F 2 offspring with varied number of vertebrae and validated the causal mutation by whole-genome association analysis. We verified its function using CRISPR-Cas9 genome editing. Our results provide insights into chromosomal speciation and phenotypic evolution and a foundation of genetic variants for the breeding of sheep and other animals., (© 2022 Li et al.; Published by Cold Spring Harbor Laboratory Press.)

The purpose of this study was to obtain immunogenic proteins and potential proteins of interest that were isolated from Mycoplasma capricolum subsp. capripneumoniae (Mccp) by MALDI-TOF mass spectrometry. One-dimensional SDS-PAGE and two-dimensional gel electrophoresis of whole cell preparation were conducted, and membrane proteome maps were prepared by immunoblotting. One-dimensional SDS-PAGE identified three immunogenic proteins with molecular masses in the range 29-97.2 kDa, two of which were in the membrane protein fraction. After two-dimensional gel electrophoresis, 20 highly immunogenic proteins were identified in the whole cell protein preparation while 9 immunogenic proteins were identified in the membrane protein fraction. This indicated that membrane proteins were the principle immunogenic proteins in Mccp. These proteins may have potential for the development of improved diagnostic tests and possible vaccines.

Haemophilus parasuis is known to produce a group of virulence-associated autotransporter (AT) proteins, VtaAs; however, no other ATs have been characterized yet. On the basis of the reported sequence of a putative espP2 gene for extracellular serine protease (ESP)-like protein of H. parasuis, this putative AT gene was successfully amplified from H. parasuis serotype 5 field strain HPS0819, cloned and sequenced. The confirmed ORF sequence showed 100% identity with the reported putative espP2 gene. The recombinant ESP-like protein purified from Escherichia coli with a pET expression system was used for immunological characterization. An approximately 85 kDa antigen was detected in cultured H. parasuis by using antiserum to the purified ESP-like protein, and antibodies against the recombinant ESP-like protein were detected in a selected serum from pigs with experimental H. parasuis infection. The results indicated that H. parasuis could produce ESP-like protein in vitro and in vivo. In an immune protection study using guinea pigs, 6 out of 10 animals immunized with the recombinant ESP-like protein survived after challenge with 5 × 10(9) bacteria of strain HPS0819, whereas 7 out of 10 animals immunized with formalin-inactivated H0819 bacterin survived after challenge. The results suggest that ESP-like protein could be one of the vaccine antigen candidates for H. parasuis infection.

Outer membrane proteins (OMPs) are the major virulent factors of Haemophilus parasuis. PCR-RFLP targeting the ompA gene was conducted to investigate the possibility of genotyping H. parasuis in this study. Fifteen reference strains and 49 isolates from pig farms in northwest China were genotyped by PCR-RFLP with a pair of specific primers. The results indicated that both the 15 reference strains and 49 isolates could be classified into 8 different genotypes by PCR-RFLP, respectively. Seven genotypes including AA, BB, BA, CA, BC, BD and CD existed simultaneously in the reference strains and isolates, but genotype CB only existed in the isolated strains. Interestingly, genotypes BA, CD and CA were only found in diseased pigs and accounted for 38.8%, 22.4% and 18.4% of the isolates, respectively. On the other hand, strains isolated from apparently healthy pigs were classified into genotypes AA, BB, BC and CB. However, the virulent reference serovar 1 strain has an AA genotype, and the fact that nearly all strains from the healthy pigs belonged to serovars classed as virulent suggests that these genotypes might also include virulent strains; therefore, further validation with more field strains is needed. The capability of the RFLP-PCR method based on the ompA gene for genotyping H. parasuis isolates indicates that this method may be a useful tool for epidemiological study.

Haemophilus parasuis infection is of considerable economic importance in the swine industry due to the high costs associated with treatment and loss of animals all over the world. In the present study, loop-mediated isothermal amplification (LAMP) is described for the rapid and specific detection of this species. A primer set derived from the inf B gene of H. parasuis was used to validate the assay using 15 H. parasuis reference strains, 39 clinical isolates, 75 positive samples, and 18 other pathogens. The results indicated that positive reactions were confirmed for all H. parasuis strains and specimens by LAMP after 45 min reaction at 65 °C in a water bath, and no cross-reactivity was observed from other non-H. parasuis strains. The detection limit of the conventional PCR was 25 copies, while that of the LAMP was five copies per tube. Therefore, the sensitivity of LAMP was higher than that of PCR. LAMP is likely to be more suitable as a routine diagnostic tool, especially in clinics without complicated equipment such as thermal cycling machines and electrophoresis apparatus. In these scenarios, the H. parasuis LAMP assay has the potential for field diagnosis.

Endogenous digitalis-like compound (EDLC) is an endogenous ligand of the digitalis receptor and can remarkably inhibit Na+/K+-ATPase activity. Antidigoxin antiserum (ADA), a selective EDLC antagonist, may lessen myocardial reperfusion injury; however, the molecular mechanisms underlying the effect remain unclear. Therefore, this study investigated whether ADA may prevent myocardial reperfusion injury and modulate gene expression of sodium pump alpha isoforms. Cardiac function was examined in isolated rat hearts subjected to ischemia and reperfusion (I/R). The infarct size, EDLC level, Na+/K+-ATPase activity, and the levels of mRNA for sodium pump alpha isoforms were measured in vivo I/R rat hearts in the presence or absence of ADA. It was found that ADA significantly improved the recovery of cardiac function, decreased infarct size, decreased EDLC level, and recovered Na+/K+-ATPase activity in I/R hearts. Further studies showed that sodium pump alpha1, alpha2, and alpha3 isoform mRNA levels were significantly reduced in I/R hearts, and pretreatment with ADA induced a large increase in the mRNA levels. These results indicate that EDLC may participate in depressing Na+/K+-ATPase activity and sodium pump alpha isoform gene expression in I/R heart. It is suggested that treatment with ADA may prevent EDLC-mediated reperfusion injury via modulating sodium pump isoform gene expression.