Superoxide dismutases: marker in predicting reduced left ventricular ejection fraction in patients with type 2 diabetes and acute coronary syndrome.

AIM: To examine the prognostic value of superoxide dismutase (SOD) activity for monitoring reduced left ventricular ejection fraction(LVEF)in the patients with type 2 diabetes and acute coronary syndrome (ACS). METHODS: The population of this cross-sectional study included 2377 inpatients with type 2 diabetes who had an ACS admitted to the Shandong Provincial Hospital Affiliated to Shandong First Medical University from January 2016 to January 2021. RESULTS: Diabetic patients with ACS were divided into 2 subgroups based on LVEF. The mean SOD activity was significantly lower in patients with an LVEF ≤ 45% than in those with an LVEF > 45% (149.1 (146.4, 151.9) versus 161.9 (160.8, 163.0)). Using ROC statistic, a cut-off value of 148.8 U/ml indicated an LVEF ≤ 45% with a sensitivity of 51.6% and a specificity of 73.7%. SODs activity were found to be correlated with the levels of NT-proBNP, hs-cTnT, the inflammatory marker CRP and fibrinogen. Despite taking the lowest quartile as a reference (OR 0.368, 95% CI 0.493-0.825, P = 0.001) or examining 1 normalized unit increase (OR 0.651, 95% CI 0.482-0.880, P = 0.005), SOD activity was found to be a stronger predictor of reduced LVEF than CRP and fibrinogen, independent of confounding factors. CONCLUSIONS: Our cross-sectional study suggests that SOD activity might be a valuable and easily accessible tool for assessing and monitoring reduced LVEF in the diabetic patients with ACS.

Antibiotic synergist OM19r reverses aminoglycoside resistance in multidrug-resistant Escherichia coli.

Introduction: The continued emergence and spread of multidrug-resistant (MDR) bacterial pathogens require a new strategy to improve the efficacy of existing antibiotics. Proline-rich antimicrobial peptides (PrAMPs) could also be used as antibacterial synergists due to their unique mechanism of action. Methods: Utilizing a series of experiments on membrane permeability, In vitro protein synthesis, In vitro transcription and mRNA translation, to further elucidate the synergistic mechanism of OM19r combined with gentamicin. Results: A proline-rich antimicrobial peptide OM19r was identified in this study and its efficacy against Escherichia coli B2 (E. coli B2) was evaluated on multiple aspects. OM19r increased antibacterial activity of gentamicin against multidrug-resistance E. coli B2 by 64 folds, when used in combination with aminoglycoside antibiotics. Mechanistically, OM19r induced change of inner membrane permeability and inhibited translational elongation of protein synthesis by entering to E. coli B2 via intimal transporter SbmA. OM19r also facilitated the accumulation of intracellular reactive oxygen species (ROS). In animal models, OM19r significantly improved the efficacy of gentamicin against E. coli B2. Discussion: Our study reveals that OM19r combined with GEN had a strong synergistic inhibitory effect against multi-drug resistant E. coli B2. OM19r and GEN inhibited translation elongation and initiation, respectively, and ultimately affected the normal protein synthesis of bacteria. These findings provide a potential therapeutic option against multidrug-resistant E. coli.

Impact of Sub-MIC Eugenol on Klebsiella pneumoniae Biofilm Formation via Upregulation of rcsB.

The Rcs phosphorelay system is present in many members of the Enterobacteriaceae. The aim of this study was to illustrate the possible mechanisms of eugenol on ultimate targets of Klebsiella pneumoniae (K. pneumoniae) Rcs phosphorelay, rcsB, and impact on biofilm formation. The minimum inhibitory concentration (MIC) of eugenol against K. pneumoniae KP1 and KP1 ΔrcsB strain was determined using the 2-fold micro-dilution method. Biofilm was measured by crystal violet staining. Transcriptome sequencing was performed to investigate sub-MIC eugenol on K. pneumoniae, and gene expression at mRNA level was analyzed by RT-qPCR. In vitro biofilm formation test and molecular docking were used to evaluate the effect of eugenol and to predict potential interactions with RcsB. MicroScale Thermophoresis (MST) was conducted for further validation. MIC of eugenol against K. pneumoniae KP1 and KP1 ΔrcsB strain was both 200 µg/ml. Transcriptome sequencing and RT-qPCR results indicated that rpmg, degP, rnpA, and dapD were downregulated, while rcsB, rcsD, rcsA, yiaG, and yiaD were upregulated in the eugenol-treated group. ΔrcsB exhibited a weakened biofilm formation capacity. Additional isopropyl-ß-d-thiogalactoside (IPTG) hinders biofilm formation, while sub-MIC eugenol could promote biofilm formation greatly. Docking analysis revealed that eugenol forms more hydrophobic bonds than hydrogen bonds. MST assay also showed a weak binding affinity between eugenol and RcsB. These results provide significant evidence that rcsB plays a key role in K. pneumoniae biofilm formation. Sub-MIC eugenol facilitates biofilm formation to a large extent instead of inhibiting it. Our findings reveal the potential risk of natural anti-biofilm ingredients at sub-MIC to treat drug-resistance bacteria.

Identification of Olfactory Genes From the Greater Wax Moth by Antennal Transcriptome Analysis.

The olfactory system is used by insects to find hosts, mates, and oviposition sites. Insects have different types of olfactory proteins, including odorant-binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors (ORs), ionotropic receptors (IRs), and sensory neuron membrane proteins (SNMPs) to perceive chemical cues from the environment. The greater wax moth, Galleria mellonella, is an important lepidopteran pest of apiculture. However, the molecular mechanism underlying odorant perception in this species is unclear. In this study, we performed transcriptome sequencing of G. mellonella antennae to identify genes involved in olfaction. A total of 42,544 unigenes were obtained by assembling the transcriptome. Functional classification of these unigenes was determined by searching against the Gene Ontology (GO), eukaryotic orthologous groups (KOG), and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. We identified a total of 102 olfactory-related genes: 21 OBPs, 18 CSPs, 43 ORs, 18 IRs, and 2 SNMPs. Results from BLASTX best hit and phylogenetic analyses showed that most of the genes had a close relationship with orthologs from other Lepidoptera species. A large number of OBPs and CSPs were tandemly arrayed in the genomic scaffolds and formed gene clusters. Reverse transcription-quantitative PCR results showed that GmelOBP19 and GmelOR47 are mainly expressed in male antennae. This work provides a transcriptome resource for olfactory genes in G. mellonella, and the findings pave the way for studying the function of these genes.

Preparation, Characterization and Pharmacokinetic Study of N-Terminal PEGylated D-Form Antimicrobial Peptide OM19r-8.

Recently, new cationic antibacterial peptide OM19R has been designed with low minimum inhibitory concentration (MIC) values against some gram-negative bacteria, such as Escherichia coli, Salmonella, and Shigella. However, this hybrid peptide, like most antibacterial peptides, has low enzyme stability and short half-life, which, in turn, increases the drug's cost. In this study, an antibacterial peptide (OM19r-8) was obtained containing some D-Arg amino acids. The new preparations were carried out through the replacement of l-Arginine by d-Arginine and the addition of PEG chains. Firstly, eight OM19r series of antibacterial peptides were obtained by designing D-Arg. Then, a polyethylene glycol-modified product mPEG5-butyrALD-OM19r-8 (mPEG5-OM19r-8) was isolated and purified by reverse-phase high-performance liquid chromatography (RT-HPLC). The enzyme stability test showed that the resistance of antibacterial peptide OM19r-8 to protease degradation increased by 4-32-fold. Moreover, the Time-kill studies showed that the germicidal kinetics curves of mPEG5-OM19r-8 and OM19r-8 to Escherichia coli had a similar trend, thus suggesting that PEG modification has an acceptable effect on the activity of the original peptide. Furthermore, the elimination of half-life (28.09 ± 2.81min) of mPEG5-OM19r-8, and the area under the drug concentration-time curve (2686.48 ± 651.36min∗ug/ml) was significantly prolonged. The current study demonstrates an example that optimizes the AMP by utilizing L-to-D amino acid replacement and including PEG chains. These results provide useful data for the clinical application of the mPEG5-OM19r-8.

Identification and Expression Profiles of 14 Odorant-Binding Protein Genes From Pieris rapae (Lepidoptera: Pieridae).

The small white butterfly, Pieris rapae (L.), is an important insect pest of Brassica crops. This species utilize olfactory cues to find their hosts and mates. However, the molecular mechanism underlying the olfactory perception in this species remains unclear. Here, we identified 14 odorant-binding proteins (OBP) genes-essential for insect olfaction-in P. rapae by exploring a previously published transcriptome dataset. Proteins encoded by all of these genes contain N-terminal signal peptides and six positionally conserved cysteine residues, which are characteristic of insect OBPs. These OBPs displayed high amino acid identity with their respective orthologs in other lepidopterans, and several conserved motifs were identified within these OBPs. Phylogenetic analysis showed that these OBPs were well segregated from each other and clustered into different branches. PrapOBP1 and PrapOBP2 were clustered into the 'general odorant-binding protein' clade, and PrapOBP3 and PrapOBP4 fall into the 'pheromone-binding protein' clade. The 14 OBP genes were located on seven genomic scaffolds. Of these, PrapOBP1, 2, 3, and 4 were located on scaffold332, whereas PrapOBP5, 6, 7, 8, and 9 were located on scaffold116. Ten of the 14 genes had antenna-biased expression. Of these, PrapOBP1, 2, 4, and 13 were enriched in male antennae, whereas PrapOBP7 and PrapOBP10 were female-biased. Our findings suggest that these OBPs may be involved in olfactory communication. To the best of our knowledge, this is the first report on the identification and characterization of OBPs in P. rapae, and our findings provide a solid foundation for studying the functions of these genes.

High Cell Selectivity and Bactericidal Mechanism of Symmetric Peptides Centered on d-Pro-Gly Pairs.

Antimicrobial peptides (AMPs) have a unique action mechanism that can help to solve global problems in antibiotic resistance. However, their low therapeutic index and poor stability seriously hamper their development as therapeutic agents. In order to overcome these problems, we designed peptides based on the sequence template XXRXXRRzzRRXXRXX-NH2, where X represents a hydrophobic amino acid like Phe (F), Ile (I), and Leu (L), while zz represents Gly-Gly (GG) or d-Pro-Gly (pG). Showing effective antimicrobial activity against Gram-negative bacteria and low toxicity, designed peptides had a tendency to form an α-helical structure in membrane-mimetic environments. Among them, peptide LRpG (X: L, zz: pG) showed the highest geometric mean average treatment index (GMTI = 73.1), better salt, temperature and pH stability, and an additive effect with conventional antibiotics. Peptide LRpG played the role of anti-Gram-negative bacteria through destroying the cell membrane. In addition, peptide LRpG also exhibited an anti-inflammatory activity by effectively neutralizing endotoxin. Briefly, peptide LRpG has the potential to serve as a therapeutic agent to reduce antibiotic resistance owing to its high therapeutic index and great stability.

Antibacterial mode of fibrauretine and synergistic effect with kanamycin against multi-drug resistant Escherichia coli.

OBJECTIVE: The present study evaluated the antibacterial activity and mode of action of fibrauretine on Escherichia coli (E. coli) and Staphylococcus aureus, and synergistic effect with kanamycin against multi-drug resistant E. coli. RESULTS: The fibrauretine exhibited inhibitory effect on the growth of the tested bacteria with minimum inhibitory concentration (MIC) and minimum bactericidal concentration of 2.5-5 and 5-10 mg/ml, respectively. Morphological changes of cell microstructure were observed after adding fibrauretine at MIC. The mode of action was further confirmed by measuring release of 260-nm absorbing materials and extracellular potassium ions. Checkerboard dilution test suggested that fibrauretine exhibited synergistic activity when combined with kanamycin (FICI ranging from 0.5625 to 0.625). CONCLUSIONS: Our results indicated that fibrauretine exerted synergistic effect with kanamycin and its antibacterial mode of action mainly attributed to disruption of cell membrane integrity.

Analysis of the microRNA Expression Profile of Bovine Monocyte-derived Macrophages Infected with Mycobacterium avium subsp. Paratuberculosis Reveals that miR-150 Suppresses Cell Apoptosis by Targeting PDCD4.

M. avium subsp. paratuberculosis (MAP) is the causative pathogen of Johne's disease, a chronic granulomatous enteritis that principally affects ruminants and can survive, proliferate and disseminate in macrophages. MicroRNAs (miRNAs) are important regulators of gene expression and can impact the processes of cells. To investigate the role of miRNAs in monocyte-derived macrophages (MDMs) during MAP infection, we used high-throughput sequencing technology to analyze small RNA libraries of MAP-infected and control MDMs. The results showed that a total of 21 miRNAs were differentially expressed in MDMs after MAP infection, and 8864 target genes were predicted. A functional analysis showed that the target genes were mainly involved in the MAPK signaling pathway, Toll-like receptor signaling pathway, NF-kappa B signaling pathway and apoptosis. In addition, using a dual-luciferase reporter assay, flow cytometry, and a small interfering (si)RNA knockdown assay, the role of miR-150 in regulating macrophage apoptosis by targeting the programmed cell death protein-4 (PDCD4) was demonstrated. These results provide an experimental basis to reveal the regulatory mechanism of MAP infection and suggest the potential of miRNAs as biomarkers for the diagnosis of Johne's disease in bovines.

Antimicrobial susceptibility and molecular typing of Pasteurella multocida isolated from six provinces in China.

Pasteurella multocida (P. multocida) is an important pathogen that causes bovine respiratory disease (BRD) in China and other countries. To investigate the antimicrobial susceptibility of P. multocida isolated from different provinces in China, we analyzed antimicrobial susceptibility phenotypes and pulsed-field gel electrophoresis (PFGE) types of P. multocida; then, we sequenced the complete genome of strain found to be multidrug-resistant. The isolates exhibited resistance to many antimicrobial agents, especially amikacin, sulfamethoxazole, sulfachloropyridazinesodium, macrolides, and fluoroquinolones. Pulsed-field gel electrophoresis analysis showed that a clonal spread of multidrug-resistant isolates occurred in various provinces. All of the isolates carried class I integron.

Molecular Characterization and Expression Analysis of Two Acetylcholinesterase Genes From the Small White Butterfly Pieris rapae (Lepidoptera: Pieridae).

Acetylcholinesterases (AChEs) are essential for the hydrolysis of the neurotransmitter acetylcholine and play crucial roles in the termination of neurotransmission. AChEs are encoded by the ace genes. However, the ace genes from the small white butterfly, Pieris rapae (L.) (Lepidoptera: Pieridae), remained uncharacterized. In this study, two aces (Prace1 and Prace2) were identified from P. rapae. Prace1 encoded a PrAChE1 protein consisting of 694 amino acid residues, and Prace2 encoded the 638-amino-acid PrAChE2. The two identified PrAChEs both had features typical of AChEs, including the catalytic triad, choline-binding sites, an oxyanion hole, an acyl pocket, a peripheral anionic subsite, an FGESAG motif and 14 conserved aromatic amino acids. Phylogenetic analysis showed that Prace1 and Prace2 were clustered into two distinct groups: ace1 and ace2, respectively. The two Praces were distributed on different genomic scaffolds: Prace1 on scaffold 156 and Prace2 on scaffold 430. Additionally, Prace1 consisted of three exons and two introns, whereas Prace2 consisted of six exons and five introns. One amino acid mutation (Gly324Ala) in PrAChE1 and two (Ser291Gly and Ser431Phe) in PrAChE2 were consistent with mutations in other insect AChEs that are associated with insecticide insensitivity. Both Prace1 and Prace2 were highly expressed at the fifth-instar larval stage and in the larval head, and the transcriptional levels of Prace1 were significantly higher than those of Prace2 in all of the tested life stages and tissues. This is the first report characterizing two ace genes in P. rapae. The results pave the way for functional study of these genes.

Molecular Characterization of a Mitochondrial Manganese Superoxide Dismutase From Chilo suppressalis (Lepidoptera: Crambidae).

In insects, superoxide dismutases (SODs) play a critical role in the scavenging of harmful reactive oxygen species (ROS) and protecting against oxidative stress induced by various environmental stresses. The Asiatic rice borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae), is an economically important insect pest of rice crops. In this study, a mitochondrial manganese SOD (Cs-mMnSOD) gene was characterized in C. suppressalis. The deduced Cs-mMnSOD protein has typical highly conserved features of mitochondrial manganese SODs, including four manganese binding residues, the signature DVWEHAYY peptide, and a mitochondrial-targeting sequence at the N-terminus. Transcription of Cs-mMnSOD was detectable at all developmental stages, but highest in pupae. Furthermore, the mRNA level of Cs-mMnSOD was strongly upregulated (more than twofold increase) following exposure to low and high temperatures (4, 30 and 35°C), insecticides (chlorpyrifos and chlorantraniliprole), and chemical reagents (cumene hydroperoxide, paraquat, H2O2 and CdCl2), but slightly elevated (less than twofold increase) in response to 8°C, abamectin and CuSO4. Additionally, the Cs-mMnSOD transcription results were consistent with the enzymatic activity data of the protein product. Purified recombinant Cs-mMnSOD protein expressed in Escherichia coli displayed SOD activity and thermostability. Furthermore, E. coli cells overexpressing Cs-mMnSOD exhibited long-term resistance to the oxidative inducers cumene hydroperoxide and paraquat. Our findings indicate that Cs-mMnSOD plays an important role in protecting C. suppressalis against oxidative damage.

Aminoglycoside susceptibility of Pasteurella multocida isolates from bovine respiratory infections in China and mutations in ribosomal protein S5 associated with high-level induced spectinomycin resistance.

Twenty-three isolates of Pasteurella multocida were tested for susceptibility to six aminoglycoside agents and screened by polymerase chain reaction for the presence of aminoglycoside resistance genes. In addition, mutations in the resistance-determining region of strains showing a high level of induced resistance to spectinomycin strains were examined. Susceptibility testing showed that all of the isolates were resistant to at least two types of aminoglycosides, and that the most effective antimicrobial was spectinomycin. The resistance genes aphA1, strB and aacA4 were present in all 23 isolates. In the three induced spectinomycin-resistant strains, a 9-bp deletion in rpsE that encodes ribosomal protein S5 was detected.

Direct Bilirubin Levels and Risk of Metabolic Syndrome in Healthy Chinese Men.

BACKGROUND: Serum bilirubin is a potent endogenous antioxidant with anti-inflammatory properties. Several cross-sectional studies have reported that bilirubin was negatively associated with metabolic syndrome. However, in recent longitudinal studies, the relations between bilirubin and metabolic syndrome are inconsistent. Moreover, previous studies mainly focused on serum total bilirubin which is the sum of direct bilirubin and indirect bilirubin. For these reasons, the longitudinal effect of bilirubin subtypes on incident metabolic syndrome was evaluated in Chinese men. METHODS: The study cohort involved 1339 Chinese men without metabolic syndrome. Metabolic syndrome was defined by the American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI) criteria, using BMI for the replacement of waist circumference. RESULTS: There are 117 incident metabolic syndrome cases (8.7%) during 5 years of follow-up among 1339 metabolic syndrome-free participants at baseline. After adjusting for age, drinking, smoking, physical activity, TG, and LDL-C, the odd ratios (ORs) and 95% confidence intervals (CIs) for MetS incidence in the second, third, and fourth quartiles versus the first quartile of DBil concentration were 1.00 (0.61-1.63), 0.57 (0.32-1.02), and 0.51 (0.28-0.92) (Ptrend = 0.031), respectively. CONCLUSIONS: Our findings support the negative association between direct bilirubin and incident metabolic syndrome in healthy Chinese men over 5-year period.

[Effect of Tangshenkang Granule containing serum on renal mesangial cells' proliferation and TGF-ß1/Smad2/3 pathway in the high glucose condition].

OBJECTIVE: To study the effect of Tangshenkang Granule (TG) containing serum on renal mesangial cells' (RMCs) proliferation and TGF-ß1/Smad2/3 pathway in the high glucose condition. METHODS: Twelve SD rats were randomly divided into four groups, i.e., the low dose TG group, the middle dose TG group, the high dose TG group, and the blank control group, 3 in each group. After 7-day gastrogavage via portal vein blood, rats were sacrificed and their serum samples were collected. RMCs were cultured in common rat serum and TG containing serum respectively. The proliferation of mesangial cells was determined by methly thiazolyl tetrazolium (MTT) assay to determine the optimal TG containing serum concentration. Expression levels of TGF-ß1 mRNA and protein were determined by real time quantitative PCR and ELISA. Smad2/3 protein expression and phosphorylation were determined by Western blot and immunofluorescence. RESULTS: TG containing serum at different doses could inhibit high glucose induced RMC cells' proliferation, TGF-ß1 over-expression and Smad2/3 phosphorylation. CONCLUSION: TG containing serum could inhibit high glucose induced RMC cells' proliferation, and its mechanism might be possibly associated with inhibiting TGF-ß1/Smad2/3 signaling pathway.

The full-length genome analysis of a street rabies virus strain isolated in Yunnan province of China.

The epidemic of rabies has rapidly increased and expanded in Yunnan province in recent years. In order to further analyze and understand the etiological reasons for the rapid expansion of rabies in Yunnan, a strain of rabies virus CYN1009D in Yunnan was isolated, and the complete genomic sequencing was carried out, and the bioimfomative analysis on genes/encoded proteins and phylogeny with reference to sequences in GenBank was performed. The complete genome of CYN1009D was 11923 nt in length and belonged to genotype I. The genes encoding different structural proteins were all conserved in their lengths, in comparison to other strains in China. The amino acid sequence was conserved at different antigen sites of NP, but the variation was detected at the secondary phosphorylation site of position 375; variations were also detected in the phosphorylation sites at positions 63-63 and 162 of PP; the sites playing important roles in virus synthesis, budding and viral morphology in MP were conserved; two glycosylation sites were detected at Asn37 and Asn319 in GP, the neutralizing antigen sites in GP were conserved; the initial amino acid of LP (ML) was different from that of most of the strains in China (MM); the variations in G-L region in the intergenic region were significant. The phylogenic tree showed that CYN1009D has a closer genetic relationship to the strains in Southeast Asia, indicating that prevention and control on rabies in borderland areas should be reinforced meanwhile efforts are made to control rabies in China.

Effects of chronic ethanol consumption on levels of adipokines in visceral adipose tissues and sera of rats.

AIM: To investigate the effects of ethanol on adipokines (leptin, adiponectin, resistin, visfatin and cartonectin) levels in visceral adipose tissue (VAT) and sera, and explore the correlation between VAT and serum adipokine levels. METHODS: Forty-eight Wistar rats were randomly divided into control, low, middle and high ethanol treatment groups that received 0, 0.5, 2.5, or 5.0 g of ethanol x kg(-1) x d(-1), respectively, via gastric tubes for 22 weeks. The levels of fasting blood glucose (FBG) and fasting serum insulin (FINS) were measured and homeostasis model assessment of insulin resistance (HOMA-IR) values were calculated. Adipokines in perirenal and epididymal VAT and sera were measured by enzyme-linked immunosorbent assays (ELISAs). RESULTS: High-dose treatments of ethanol (vs control group) significantly increased FINS (eg 37.86%) and HOMA-IR values (eg 40.63%). In VAT, levels of leptin, resistin and visfatin in the middle- and high-dose groups were significantly elevated, whereas adiponectin and cartonectin levels decreased. In sera, changes in adipokine levels were similar to that observed in VAT, with the exception of cartonectin. These ethanol-induced effects were dose-dependent. A positive correlation existed between VAT and serum adipokine levels, except for cartonectin. CONCLUSION: Chronic ethanol consumption affects adipokine levels in VAT and sera in a dose-dependent manner, with the exception of serum cartonectin. The altered levels of adipokines in VAT and sera are positively correlated.

[Cloning and expression of Mycobacterium bovis secreted protein MPB51 in Escherichia coli].

The gene encoding MPB51 was amplified from M. bovis Valleel11 chromosomal DNA using PCR technique, and the PCR product was approximately 800 bp DNA segment. Using T-A cloning technique, the PCR product was cloned into pGEM-T vector and cloning plasmid pGEM-T-51 was thus constructed successfully. pGEM-T-51 and pET28a( + ) were digested by BamH I and EcoR I double enzymes. The purified MPB51 gene was subcloned into the expression vector pET28a( + ), and the prokaryotic expression vector pET28a-51 was thus constructed. Plasmid containing pET28a-51 was transformed into competence E. coli BL21 (DE3). The bacterium was induced by IPTG and its lysates were loaded directly onto SDS-PAGE, approximately 30 kD exogenous protein was observed on the SDS-PAGE. The protein was analyzed using Western blot. The results indicate that the protein is antigenic activity of MB. The results are expected to lay foundation for further studies on the subunit vaccine and DNA vaccine of MPB51 gene in their prevention of bovine tuberculosis.