Alpha-toxin Research Articles

Clonal diversity of Clostridium perfringens human clinical isolates with various toxin gene profiles based on multilocus sequence typing and alpha-toxin (PLC) typing

ObjectivesClostridium perfringens is a common anaerobic pathogen causing enteritis/enterocolitis and wound infections in humans. We analyzed clonal diversity and toxin gene prevalence in C. perfringens clinical isolates from humans in northern Japan. MethodsPrevalence of nine toxin genes was analyzed for 585 C. perfringens isolates from patients collected for 20-month period between May 2019 and December 2020 by molecular methods. Sequence type (ST) based on multilocus sequence typing (Xiao's scheme) and alpha-toxin (PLC) sequence type were determined for a total of 124 isolates selected in the present study along with those in our previous study (2017–2018). ResultsToxinotypes A (68.2%) was the most frequent, followed by F (31.6%), and G (0.2%), while additional toxin genes encoding binary enterotoxin (BEC/CPILE) and beta2 toxin were identified in one and six isolates, respectively. Among the 124 isolates with various toxin gene profiles, 62 STs including 53 novel types were identified, revealing the presence of six clonal complexes (CCs) consisting of 27 STs. Most of enterotoxin gene (cpe)-positive isolates belonged to CC36, CC41, and CC117. Based on 22 key amino acids in alpha toxin sequence, four PLC types (I-IV) including 21 subtypes were classified, and their relation to individual STs/CCs was clarified. Two isolates harboring bec/cpile belonged to different STs (ST95, ST131) and PLC types (If, IVb), indicating distribution of this toxin gene to distinct lineages. ConclusionsThe present study revealed the diversity in C. perfringens clones of human origin with various toxin gene profiles represented by ST/CC and PLC type.

Design of a chitosan-based nano vaccine against epsilon toxin of Clostridium perfringens type D and evaluation of its immunogenicity in BALB/c mice.

Background and purpose:Clostridium perfringens is an anaerobic, spore-forming, and pathogenic bacterium that causes intestinal diseases in humans and animals. In these cases, therapeutic intervention is challenging; because the disease progresses much rapidly. This bacterium can produce 5 main toxins (alpha, beta, epsilon, iota, and a type of enterotoxin) among which the epsilon toxin (ETX) is used for bioterrorism. This toxin can be prevented by immunization with specific immunogenic vaccines. In the present research, we aimed at developing a recombinant chitosan-based nano-vaccine against ETX of C. perfringens and evaluate its effects on the antibody titration against epsilon toxin in BALB/c mice as the vaccine model.Experimental approach:The etx gene from C. perfringens type D was cloned and expressed in E. coli. After analysis by SDS-PAGE and western blotting, the expressed products were purified, and the obtained proteins were used for immunization in mice as a chitosan nanoparticle containing recombinant, purified ETX, and protein.Findings/Results:The results of ELISA showed that IgA antibody serum level increased sufficiently using recombinant protein with nanoparticle as an oral and injectable formulation. IgG antibody titers increased significantly after administrating the recombinant proteins with nanoparticles through both oral delivery and intravenous injection.Conclusion and implication:In conclusion, the recombinant ETX is suggested as a good candidate for vaccine production against diseases caused by ETX of C. perfringens type D.

Increased Risk of Thrombocytopenia and Death in Patients with Bacteremia Caused by High Alpha Toxin-Producing Methicillin-Resistant Staphylococcus aureus.

Alpha toxin (Hla) is a major virulence factor of Staphylococcus aureus that targets platelets but clinical data on Hla pathogenesis in bacteremia (SAB) is limited. We examined the link between in vitro Hla activity and outcome. Study isolates obtained from 100 patients with SAB (50 survivors; 50 non-survivors) were assessed for in vitro Hla production by Western immunoblotting in a subset of isolates and Hla activity by hemolysis assay in all isolates. Relevant demographics, laboratory and clinical data were extracted from patients’ medical records to correlate Hla activity of the infecting isolates with outcome. Hla production strongly correlated with hemolytic activity (rs = 0.93) in vitro. A trend towards higher hemolytic activity was observed for MRSA compared to MSSA and with high-risk source infection. Significantly higher hemolytic activity was noted for MRSA strains isolated from patients who developed thrombocytopenia (median 52.48 vs. 16.55 HU/mL in normal platelet count, p = 0.012) and from non survivors (median 30.96 vs. 14.87 HU/mL in survivors, p = 0.014) but hemolytic activity of MSSA strains did not differ between patient groups. In vitro Hla activity of MRSA strains obtained from patients with bacteremia is significantly associated with increased risk for thrombocytopenia and death which supports future studies to evaluate feasibility of bedside phenotyping and therapeutic targeting.

Nicotiana spp. for the Expression and Purification of Functional IgG3 Antibodies Directed Against the Staphylococcus aureus Alpha Toxin

Immunoglobulin subclass IgG1 is bound and neutralized effectively by Staphylococcus aureus protein A, allowing the bacterium to evade the host’s adaptive immune response. In contrast, the IgG3 subclass is not bound by protein A and can be used to treat S. aureus infections, including drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA). However, the yields of recombinant IgG3 are generally low because this subclass is prone to degradation, and recovery is hindered by the inability to use protein A as an affinity ligand for antibody purification. Here, we investigated plants (Nicotiana spp.) as an alternative to microbes and mammalian cell cultures for the production of an IgG3 antibody specific for the S. aureus alpha toxin. We targeted recombinant IgG3 to different subcellular compartments and tested different chromatography conditions to improve recovery and purification. Finally, we tested the antigen-binding capacity of the purified antibodies. The highest IgG3 levels in planta (>130 mg kg−1 wet biomass) were achieved by targeting the endoplasmic reticulum or apoplast. Although the purity of IgG3 exceeded 95% following protein G chromatography, product recovery requires further improvement. Importantly, the binding affinity of the purified antibodies was in the nanomolar range and thus comparable to previous studies using murine hybridoma cells as the production system.

English

Necrotic enteritis (NE) is one of the important enteric disease in the poultry industry worldwide, caused by C. perfringens type A. This study describes the isolation, identification, and toxinotyping of C. perfringens in necrotic enteritis affected broiler chicken in Pakistan. A total of 430 intestinal samples from dead carcasses and birds suspected of NE outbreak, in and around Faisalabad, Pakistan were collected from 36 broiler farms which yielded 87 alpha toxin gene (cpa) positive C. perfringens type A isolates. The birds having 4-5 weeks of age, clinical signs, and reared in open (conventional) sheds showed higher C. perfringens isolation rate. The study concluded netB negative C. perfringens type A as a causative agent for NE outbreaks in broiler birds in Faisalabad, Pakistan.

Measurement over 1 Year of Neutralizing Antibodies in Cattle Immunized with Trivalent Vaccines Recombinant Alpha, Beta and Epsilon of Clostridium perfringens.

The alpha (CPA), beta (CPB) and epsilon (ETX) toxins of Clostridium perfringens are responsible for causing diseases that are difficult to eradicate and have lethal potential in production animals. Vaccination of herds is still the best control strategy. Recombinant clostridial vaccines have shown good success at inducing neutralizing antibody titers and appear to be a viable alternative to the conventional production of commercial clostridial toxoids. Research is still needed on the longevity of the humoral immune response induced by recombinant proteins in immunized animals, preferably in target species. The objective of this study was to measure the humoral immune response of cattle immunized with trivalent vaccines containing the recombinant proteins alpha (rCPA), beta (rCPB) and epsilon (rETX) of C. perfringens produced in Escherichia coli at three different concentrations (100, 200, and 400 µg) of each protein for 12 months. The recombinant vaccines containing 200 (RV2) and 400 µg (RV3) yielded statistically similar results at 56 days. They performed better throughout the study period because they induced higher neutralizing antibody titers and were detectable for up to 150 and 180 days, respectively. Regarding industrial-scale production, RV2 would be the most economical and viable formulation as it achieved results similar to RV3 at half the concentration of recombinant proteins in its formulation. However, none of the vaccines tested induced the production of detectable antibody titers on day 365 of the experiment, the time of revaccination typically recommended in vaccination protocols. Thus, reiterating the need for research in the field of vaccinology to achieve greater longevity of the humoral immune response against these clostridial toxins in animals, in addition to the need to discuss the vaccine schedules and protocols adopted in cattle production.

Humoral Immune Response Evaluation in Horses Vaccinated with Recombinant Clostridium perfringens Toxoids Alpha and Beta for 12 Months.

In horses, Clostridium perfringens is associated with acute and fatal enterocolitis, which is caused by a beta toxin (CPB), and myonecrosis, which is caused by an alpha toxin (CPA). Although the most effective way to prevent these diseases is through vaccination, specific clostridial vaccines for horses against C. perfringens are not widely available. The aim of this study was to pioneer the immunization of horses with three different concentrations (100, 200 and 400 µg) of C. perfringens recombinant alpha (rCPA) and beta (rCPB) proteins, as well as to evaluate the humoral immune response over 360 days. Recombinant toxoids were developed and applied to 50 horses on days 0 and 30. Those vaccines attempted to stimulate the production of alpha antitoxin (anti-CPA) and beta antitoxin (anti-CPB), in addition to becoming innocuous, stable and sterile. There was a reduction in the level of neutralizing anti-CPA and anti-CPB antibodies following the 60th day; therefore, the concentrations of 200 and 400 µg capable of inducing a detectable humoral immune response were not determined until day 180. In practical terms, 200 µg is possibly the ideal concentration for use in the veterinary industry’s production of vaccines against the action of C. perfringens in equine species.

Steroidal saponins of Trillium govanianum: Quality control, pharmacokinetic analysis, and anti-inflammatory activity

The rhizomes of Trillium govanianum have traditionally been used in the Ayurvedic system of medicine to treat inflammation, pain, burn, and reproductive malfunctions. However, the ethanopharmacology and chemical constituents of T. govanianum have not been effusively explored to date. The present study attempted to uncover the phytochemical constituents and quality parameters of T. govanianum rhizomes, along with an evaluation of the anti-inflammatory potential of the extract, fractions, and isolated steroidal saponins. The quality of T. govanianum rhizomes was examined by standard guidelines of the Association of Official Agricultural Chemists (AOAC). The phytochemical composition of rhizomes was estimated by the spectroscopic method. The extract, fractions, and pure molecules were tested for their anti-inflammatory potential using lipopolysaccharide-stimulated RAW 264.7 macrophages. Besides that, computational pharmacokinetics properties of bioactive compounds were screened by using the Schrödinger software. The quality control parameters such as moisture content, ash value, pH, heavy metals, alpha toxins, residual pesticides, and microbial load were observed within the permitted limits as per AOAC guidelines, suggesting good quality and safe nature of T. govanianum rhizomes. Phytochemical analysis revealed the presence of steroidal saponins (78.3 ± 0.61 mg/g), phenolics (12.3 ± 2.76 mg/g), flavonoids (3.54 ± 0.24 mg/g), and carbohydrates (473 ± 2.27 mg/g) in the rhizomes. Macrophages cytocompatibility demonstrated that cell viability was not affected at any tested concentration of extract, fractions and pure compounds [diosgenin ( 1 ), borassoside D ( 2 ), and govanoside B ( 7 )]. The LPS-stimulated macrophages secreted nitric oxide (NO) and pro-inflammatory cytokines (TNF α , IL-1 β, and IL-6), which were inhibited by the extract, fractions, and compounds 1 , 2 , and 7 in a concentration-independent manner. Additionally, in silico pharmacokinetics revealed that compound 1 has good membrane-permeability followed by compound 2 , while compound 7 showed the non-membrane permeability. This study validates the traditional uses of rhizomes of T. govanianum in the treatment of inflammation, and this activity might be due to the presence of steroidal saponins . • Assessment of different quality control parameters of Trillium govanianum and all were observed within the permitted limits as per AOAC guidelines. • Phytochemical analysis revealed saponins (78.3 ± 0.61 mg/g), as the major constituents of this plant. • Anti-inflammatory and in silico pharmacokinetics activity evaluation of the extract, fractions, and three pure steroidal saponins of T. govanianum using lipopolysaccharide-stimulated RAW 264.7 macrophages. • Pure molecules effectively inhibit the production of cytokines (TNF- α , IL1 β , and IL-6) as compared with extract and fractions.

Mesoporous silica nanoparticles-based formulations of a chimeric proteinous vaccine candidate against necrotic enteritis disease

To develop a nanoparticle-based vaccine against necrotic enteritis, a chimeric antigen (rNA) consisting of the main antigens of Clostridium perfringens, NetB, and Alpha toxin, was prepared. Then, the rNA molecules were loaded onto the functionalized mesoporous silica nanoparticles (MSNPs) using physical adsorption or covalent conjugation methods. The characterization of synthesized nanoparticles was performed by scanning electron microscopy, dynamic light scattering, zeta potential measurement, Fourier transform infrared spectroscopy, and thermogravimetry techniques. The results revealed that the spherical nanoparticles with an average diameter of 90 ± 12 nm and suitable surface chemistries are prepared. MSNPs-based formulations did not show any significant toxicity on the chicken embryo fibroblast cells. The results of the challenge experiments using subcutaneous or oral administration of the as-prepared formulations in the animal model showed that the as-prepared nanosystems, similar to those formulated with a commercial adjuvant (Montanide), present stronger humoral immune responses as compared to that of the free proteins. It was also indicated that the best protection is obtained in groups vaccinated with MSNPs-based nanovaccine, especially those who orally received covalently conjugated nanovaccine candidates. These results recommend that the MSNPs-based formulated chimeric proteinous vaccine candidates can be considered as an effective immunizing system for the oral vaccination of poultry against gastrointestinal infectious diseases.

Comparative Genomics of Clostridium perfringens Reveals Patterns of Host-Associated Phylogenetic Clades and Virulence Factors.

Clostridium perfringens is an opportunistic pathogenic bacterium that infects both animals and humans. Clostridium perfringens genomes encode a diverse array of toxins and virulence proteins, which continues to expand as more genomes are sequenced. In this study, the genomes of 44 C. perfringens strains isolated from intestinal sections of diseased cattle and from broiler chickens from diseased and healthy flocks were sequenced. These newly assembled genomes were compared to 141 publicly available C. perfringens genome assemblies, by aligning known toxin and virulence protein sequences in the assemblies using BLASTp. The genes for alpha toxin, collagenase, a sialidase (nanH), and alpha-clostripain were present in at least 99% of assemblies analyzed. In contrast, beta toxin, epsilon toxin, iota toxin, and binary enterotoxin of toxinotypes B, C, D, and E were present in less than 5% of assemblies analyzed. Additional sequence variants of beta2 toxin were detected, some of which were missing the leader or signal peptide sequences and therefore likely not secreted. Some pore-forming toxins involved in intestinal diseases were host-associated, the netB gene was only found in avian isolates, while netE, netF, and netG were only present in canine and equine isolates. Alveolysin was positively associated with canine and equine strains and only present in a single monophyletic clade. Strains from ruminant were not associated with known virulence factors and, except for the food poisoning associated clade, were present across the phylogenetic diversity identified to date for C. perfringens. Many C. perfringens strains associated with food poisoning lacked the genes for hyaluronidases and sialidases, important for attaching to and digesting complex carbohydrates found in animal tissues. Overall, the diversity of virulence factors in C. perfringens makes these species capable of causing disease in a wide variety of hosts and niches.

Cloning and Expression of a Fusion Protein Containing Highly Epitopic Regions of Clostridium perfringens Epsilon Toxin and Clostridium novyi Alpha Toxin

Clostridium perfringens and novyi species are two important toxin-producing pathogens which pose a risk to the livestock health. Epsilon and alpha toxins are major toxins of these two pathogens, respectively. Advances in current vaccine industrialization lead to the utilization of toxin epitopes instead of the whole pathogen/toxoids to produce novel vaccines. In the present study, bioinformatics approaches were applied to design a fused protein containing both toxin fragments of interest with the highest antigenicity score for B-cells. To do so different specialized algorithms including I-TASSER, IEDB, ElliPro, PyDock and CLC Main Workbench were applied. The chimeric protein was successfully cloned, expressed, and purified using an immobilized-metal affinity chromatography for His-tagged proteins. During in vivo experiments on rabbits, the levels of immunization provided by the recombinant protein or native alpha and epsilon toxins were compared based on serological studies. Results indicated that the designed protein was able to stimulate effective immune responses against both alpha and epsilon toxins. This can be used as a proper strategy to design novel peptide-based subunit vaccines. Clostridium perfringens and novyi species are two important toxin-producing pathogens which pose a risk to the livestock health. Epsilon and alpha toxins are major toxins of these two pathogens, respectively. Advances in current vaccine industrialization lead to the utilization of toxin epitopes instead of the whole pathogen/toxoids to produce novel vaccines. In the present study, bioinformatics approaches were applied to design a fused protein containing both toxin fragments of interest with the highest antigenicity score for B-cells. To do so different specialized algorithms including I-TASSER, IEDB, ElliPro, PyDock and CLC Main Workbench were applied. The chimeric protein was successfully cloned, expressed, and purified using an immobilized-metal affinity chromatography for His-tagged proteins. During in vivo experiments on rabbits, the levels of immunization provided by the recombinant protein or native alpha and epsilon toxins were compared based on serological studies. Results indicated that the designed protein was able to stimulate effective immune responses against both alpha and epsilon toxins. This can be used as a proper strategy to design novel peptide-based subunit vaccines.

The Increased Accumulation of Staphylococcus aureus Virulence Factors Is Maximized in a purR Mutant by the Increased Production of SarA and Decreased Production of Extracellular Proteases.

Mutation of purR was previously shown to enhance the virulence of Staphylococcus aureus in a murine sepsis model, and this cannot be fully explained by increased expression of genes within the purine biosynthesis pathway. Rather, the increased production of specific S. aureus virulence factors, including alpha toxin and the fibronectin-binding proteins, was shown to play an important role. Mutation of purR was also shown previously to result in increased abundance of SarA. Here, we demonstrate by transposon sequencing that mutation of purR in the USA300 strain LAC increases fitness in a biofilm while mutation of sarA has the opposite effect. Therefore, we assessed the impact of sarA on reported purR-associated phenotypes by characterizing isogenic purR, sarA, and sarA/purR mutants. The results confirmed that mutation of purR results in increased abundance of alpha toxin, protein A, the fibronectin-binding proteins, and SarA, decreased production of extracellular proteases, an increased capacity to form a biofilm, and increased virulence in an osteomyelitis model. Mutation of sarA had the opposite effects on all of these phenotypes and, other than bacterial burdens in the bone, all of the phenotypes of sarA/purR mutants were comparable to those of sarA mutants. Limiting the production of extracellular proteases reversed all of the phenotypes of sarA mutants and most of those of sarA/purR mutants. We conclude that a critical component defining the virulence of a purR mutant is the enhanced production of SarA, which limits protease production to an extent that promotes the accumulation of critical S. aureus virulence factors.

Prevalence of Clostridium perfringens alpha toxin and enterotoxin in the faeces of dogs with acute haemorrhagic diarrhoea syndrome.

To investigate the prevalence of Clostridium perfringens alpha toxin encoding gene and C.perfringens enterotoxin encoding gene in dogs with acute haemorrhagic diarrhoea syndrome. Retrospective study looking at the prevalence of C. perfringens alpha toxin and C. perfringens enterotoxin in the faeces of three groups of dogs - those with acute haemorrhagic diarrhoea syndrome (n=16), those with haemorrhagic diarrhoea from another cause (n=17) and those without haemorrhagic diarrhoea (n=10). Correlation between the presence of C. perfringens alpha toxin and/or C. perfringens enterotoxin and Acute Patient Physiological and Laboratory Evaluationfast scores, acute haemorrhagic diarrhoea index scores and length of hospitalisation in dogs with acute haemorrhagic diarrhoea syndrome was assessed. Prevalence of C. perfringens alpha toxin was not higher in dogs with acute haemorrhagic diarrhoea syndrome (43.75%) than dogs with haemorrhagic diarrhoea from another cause (58.82%) (difference in prevalence 15.07%; 95% CI -37% to 32%) or in dogs without haemorrhagic diarrhoea (60%) (difference in prevalence 16.25%; 95% CI -4% to 36%). Dogs with acute haemorrhagic diarrhoea syndrome did not have a significantly higher prevalence of C. perfringens enterotoxin (18.75%) compared to dogs without haemorrhagic diarrhoea (11.76%) (difference in prevalence 6.99%; 95% CI -18% to 32%). Prevalence of C. perfringens enterotoxin was similar in dogs with acute haemorrhagic diarrhoea syndrome and dogs without haemorrhagic diarrhoea (20%) (difference in prevalence 1.25% 95% CI -33% to 30%). The presence of C. perfringens alpha toxin did not correlate with increased Acute Patient Physiological and Laboratory Evaluationfast scores, acute haemorrhagic diarrhoea index scores or length of hospitalisation in dogs with acute haemorrhagic diarrhoea syndrome. This study does not demonstrate increased prevalence of C. perfringens alpha toxin or C. perfringens enterotoxin in dogs with acute haemorrhagic diarrhoea syndrome compared to dogs with haemorrhagic diarrhoea from another cause or dogs without haemorrhagic diarrhoea.

IBT-V02: A Multicomponent Toxoid Vaccine Protects Against Primary and Secondary Skin Infections Caused by Staphylococcus aureus.

Staphylococcus aureus causes a wide range of diseases from skin infections to life threatening invasive diseases such as bacteremia, endocarditis, pneumonia, surgical site infections, and osteomyelitis. Skin infections such as furuncles, carbuncles, folliculitis, erysipelas, and cellulitis constitute a large majority of infections caused by S. aureus (SA). These infections cause significant morbidity, healthcare costs, and represent a breeding ground for antimicrobial resistance. Furthermore, skin infection with SA is a major risk factor for invasive disease. Here we describe the pre-clinical efficacy of a multicomponent toxoid vaccine (IBT-V02) for prevention of S. aureus acute skin infections and recurrence. IBT-V02 targets six SA toxins including the pore-forming toxins alpha hemolysin (Hla), Panton-Valentine leukocidin (PVL), leukocidin AB (LukAB), and the superantigens toxic shock syndrome toxin-1 and staphylococcal enterotoxins A and B. Immunization of mice and rabbits with IBT-V02 generated antibodies with strong neutralizing activity against toxins included in the vaccine, as well as cross-neutralizing activity against multiple related toxins, and protected against skin infections by several clinically relevant SA strains of USA100, USA300, and USA1000 clones. Efficacy of the vaccine was also shown in non-naïve mice pre-exposed to S. aureus. Furthermore, vaccination with IBT-V02 not only protected mice from a primary infection but also demonstrated lasting efficacy against a secondary infection, while prior challenge with the bacteria alone was unable to protect against recurrence. Serum transfer studies in a primary infection model showed that antibodies are primarily responsible for the protective response.

Sequencing of Clostridium perfringens toxin genes (cpa, etx, iap) from Iraqi hospitals and detection by PCR of the genes encoding resistance to metronidazole, tetracycline, and clindamycin

PurposeThis cross sectional study was designed to investigate the molecular detection of C. perfringens toxins (alpha, epsilon, iota) and antibiotics resistance genes, as well as sequencing of their toxin genes. MethodsDifferent wound swabs were taken from 140 patients. PCR was applied for detection of clostridial toxins; alpha toxin (cpa) gene, epsilon toxin (etx) gene, and iota toxin (iap) gene. Metronidazole nim gene, tetracycline resistance genes; (tetQ, tetM, tetB, and tetW) and clindamycin resistance genes erm (A,B), were used for genotypic detection of antibiotic resistance. ResultsOut of 140 clinical samples collected, 7 isolates were detected using specific primer 16S–23S intergenic rRNA spacer gene of C. perfringens. Results showed presence of alpha toxin (cpa) genes in all clostridial isolates, Epsilon toxin (etx) genes in 2/7(28.4%), and iota toxin (iap) genes in 2/7 (28.4%). Results of antibiotic resistance genes showed that all isolates were not able to produce nim, tet W and Q, tet B, erm (A), erm (B) genes except for tetM. Gene sequence analysis for cpa gene showed that there were 3 mutations in the sample of this gene, the results of etx gene when had been sent 2 samples from this gene. The first sample showed that there was one mutation and the results of iap gene showed that there were no mutation in 2 samples of the iap gene. The samples had been showed identical 100%. ConclusionThe DNA sequence analysis of bacterial genome revealed several important feature including that may allow to confirm new the presence of toxin and to identify new or mutant toxins that may be missed by diagnostic PCR specifically target toxin encoding genes.

Preparation and evaluation of Necrotic enteritis (NE) vaccine using alpha toxin with different adjuvants in broilers.

ABSTRACT In the present study we used one hundred and twenty-five broiler chicks (Arbo) one- day old used as experimental birds, the experimental chicks were divided into five groups each of twenty-five chicks. The first group kept as control, the 2nd group was non-vaccinated and challenged, the 3rd group was infected with Emeria tenella at 15th days of age and challenged, the 4th group was vaccinated and challenged, the 5th group was vaccinated and challenged. The vaccinated chicks in group 4 was vaccinated by locally prepared NE vaccine adjuvinated with Aluminum hydroxide by dose of 0.5ml subcutaneously at age of seven days and boostered at age of eighteen days. While the chicks of 5th group were vaccinated by locally prepared NE vaccine adjuvinated with Montanide oil. The challenged groups (2, 3, 4 and 5) were challenged at age of 27, 28 and 29 days with C. perfringes type A whole culture by dose of 3ml contains 109 Cfu. Serum samples were collected after challenge at thirty-five days. The results showed that higher immune response, lower mortality rate, increase in body weight and low feed conversion rate in chicks of group 5 compared to chicks of groups (1, 2, 3 and 4).

Phenotypic detection and genotyping of Clostridium perfringens associated with enterotoxemia in sheep in the Qassim Region of Saudi Arabia.

Background and Aim:Enterotoxemia caused by Clostridium perfringens toxinotypes is an often fatal disease of sheep of all ages, with a substantial economic loss to the sheep industry. This study was conducted to isolate C. perfringens from suspected cases of enterotoxemia in sheep in the central part of the Qassim Region, Saudi Arabia, and to determine the prevalent toxinotype by detecting alpha (cpA), beta (cpB), and epsilon (etX) toxin genes, which might help control this disease locally.Materials and Methods:A total of 93 rectal swabs and intestinal content samples were collected from diseased and animals suspected of having died of enterotoxemia in early 2020. Samples were subjected to bacteriological examination, biochemical analysis of isolates by VITEK 2, and molecular toxinotyping of isolates by LightCycler® real-time polymerase chain reaction (RT-PCR).Results:Our results revealed that only 14 isolates were confirmed by VITEK 2 as being C. perfringens, with excellent identification (probability of 95% and 97%). According to the toxinotyping of isolates by RT-PCR, all 14 isolates possessed both the cpA and etX toxin genes, while the cpB toxin gene was not detected in any of the isolates.Conclusion:Our findings demonstrated that C. perfringens type D was the only toxinotype found in the central part of the Qassim Region in 2020; moreover, according to the culture method, only 15% (14/93) of the suspected cases of enterotoxemia were confirmed to be caused by C. perfringens infection, which highlighted the importance of clinical and laboratory differential diagnosis of enterotoxemia in sheep.

Evaluation and Comparison of Clostridium Epsilon-Alpha Fusion Gene Expression Using Different Commercial Expression Vector.

Clostridium perfringens and Clostridium septicum are gram-positive, anaerobic, spore-forming rods and pathogens for humans and livestock, which are widespread in nature as well as human and animal digestive systems. C. perfringens produces numerous different exoproteins, which are various systems of action. The major C. perfringens toxins include alpha, beta, epsilon, and iota. C. perfringens are classified into five groups (A-E) on the basis of the production of these lethal toxins. Furthermore, toxins secreted from C. septicum include alpha, beta, delta, and gamma. Epsilon and alpha toxins of C. perfringens and C. septicum are the major causes of enterotoxemia and braxy in sheep and goats, respectively. The production of recombinant immunogenic proteins of these bacteria using suitable expression vectors and expression prokaryotic hosts can be a convenient method for the reduction of the costs and production time of clostridial anaerobic vaccines. In the present study, recombinant Escherichia coli strain TOP10 containing pJETεα was used for the evaluation of C. perfringens type D and C. septicum epsilon-alpha fusion protein using different commercial vectors. After the extraction of pJETεα from the recombinant cell, it was digested by NdeI and XhoI restriction enzymes and subcloned into pET22b (+), pET26b (+), and pGEM-B1 expression vectors in E. coli/Rosetta and E. coli/BL21 (DE3). The expression of recombinant fusion toxin was evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotting in three different temperatures, various isopropyl β-D-1-thiogalactopyranoside (IPTG) gradients, and different times using pGEMεα, pET22εα, and pET26εα vectors in E. coli/Rosetta and E. coli/BL21 (DE3). According to the obtained results, recombinant E. coli/Rosetta/pET22εα showed better expression at a temperature of 37°C after 6 h of induction by IPTG.

Molecular Cloning of a New Bi-Functional Fusion Protein of Clostridium perfringens Type A Alpha and Clostridium septicum Alpha Toxin Genes in E. coli

Background: A synthetic construct bi-functional protein fusion includes two protein domains, or proteins bind by a fragment. The synthetic construct is designed to achieve better characterize and new functionality. Therefore, having proper cells is essential for cloning fusion genes. Clostridium perfringens type A produces the alpha-toxin and can cause gas gangrene and gastrointestinal diseases. C. septicum produces the alpha-toxin and can cause non-traumatic and traumatic gas gangrene. Objectives: The current study aimed to investigate molecular cloning of a new bi-functional fusion protein of C. perfringens alpha (cpa) and C. septicum alpha (csa) toxin genes in E. coli TOP10. In silico analysis was used for the chimeric fusion protein structural prediction. Methods: To produce chimeric fusion protein, the alpha-alpha (α-α) fusion gene was designed according to nucleotide sequences of cpa (KY584046.1) and csa (JN793989.2) genes. Tertiary structural prediction and validation of the fusion protein were determined by online software. In the new synthetic construction, α-α fusion protein genes are bind via the linker AEAAAKEAAAKA. The linker was introduced between the two domains by fusion PCR. The synthetic fusion gene was cloned into the pUC57cloning vector and then transferred into the host cell. Results: Analysis of the chimeric protein fusion is showed using the I-TASSER server as C-score equal to -2.68 as well as Rampage software in order to confirm the geometrical model as a natural like protein. Also, 1.0% agarose gel electrophoresis of fusion PCR product and sequencing analysis revealed a DNA fragment length of 2346 bp. Screening gel electrophoresis showed 996 bp length, which the designed linker was contained in it. Gel electrophoresis of extracted and purified recombinant plasmid (pUC57/αα) showed that a pUC57/αα of 5056 bp. The digested recombinant pUC57/αα showed one 2.3 kb (our fusion gene) band and one 2.7 kb (pUC57) band. Conclusions: This study presented a new approach for the fusion of cpa and csa genes based on the fusion PCR strategy. According to the latest information, this is the first time that α-α fusion gene is designed and cloned into a suitable cloning vector.

Platinum accumulation in oxaliplatin-induced peripheral neuropathy.

Oxaliplatin‐induced peripheral neuropathy (OIPN) is a common and dose‐limiting toxic effect that markedly limits the use of oxaliplatin and affects the quality of life. Although it is common, the underlying mechanisms of OIPN remain ambiguous. Recent studies have shown that the platinum accumulation in peripheral nervous system, especially in dorsal root ganglion, is a significant mechanism of OIPN. Several specific transporters, including organic cation transporters, high‐affinity copper uptake protein1 (CTR1), ATPase copper transporting alpha (ATP7A) and multidrug and toxin extrusion protein 1 (MATE1), could be associated with this mechanism. This review summarizes the current research progress about the relationship between platinum accumulation and OIPN, as well as suggests trend for the future research.