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BACKGROUND: Corynebacterium striatum (C. striatum) is a gram-positive, anaerobic bacillus found both environmentally and in human skin and nasal mucosa flora. It is reportedly the etiologic agent of community-acquired and nosocomial diseases and is significantly associated with bacteremia and medical endovascular devices. This is the rare case of mitral valve native valve endocarditis (NVE) caused by C. striatum occurring in a young adult without underlying structural heart disease or indwelling cardiovascular medical devices successfully treated with multidisciplinary therapy. CASE PRESENTATION: The patient was a 28-year-old female with no medical history. She was transferred our hospital due to sudden onset of vertigo and vomit. A computed tomography on day 2 revealed the hydrocephalus due to the cerebellar infarction, and she underwent posterior fossa decompression for cerebellar infarction. An angiography on day 8 revealed a left vertebral artery dissection, which was suspected be the etiology. Afterwards, a sudden fever of 39 degrees developed on day 38. She was diagnosed with aspiration pneumonia and treated with ampicillin/sulbactam but was still febrile at the time of transfer for rehabilitation. Treatment continued with levofloxacin, the patient had no fever decline, and she was readmitted to our hospital. Readmission blood cultures (3/3 sets) revealed C. striatum, and an echocardiogram revealed an 11 mm long mitral valve vegetation, leading to NVE diagnosis. On the sixth illness day, cardiac failure symptoms manifested. Echocardiography revealed mitral valve rupture. She was transferred again on the 11th day of illness, during which time her mitral valve was replaced. C. striatum was detected in the vegetation. Following surgery, she returned to our hospital, and vancomycin administration continued. The patient was discharged after 31 total days of postoperative antimicrobial therapy. The patient experienced no exacerbations thereafter. CONCLUSIONS: We report the rare case of C. striatum mitral valve NVE in a young adult without structural heart disease or indwelling cardiovascular devices. CLINICAL TRIAL NUMBER: Not applicable.
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Antibacterianos , Infecciones por Corynebacterium , Corynebacterium , Endocarditis Bacteriana , Humanos , Femenino , Adulto , Infecciones por Corynebacterium/microbiología , Infecciones por Corynebacterium/tratamiento farmacológico , Corynebacterium/aislamiento & purificación , Endocarditis Bacteriana/microbiología , Endocarditis Bacteriana/tratamiento farmacológico , Antibacterianos/uso terapéutico , Válvula Mitral/cirugía , Válvula Mitral/microbiologíaRESUMEN
Bacteriophages have evolved different mechanisms of infection and penetration of bacterial cell walls. In Siphoviridae-like viruses, the inner tail proteins have a pivotal role in these processes and often encode lytic protein domains which increase infection efficiency. A soluble lytic transglycosylase (SLT) domain was identified in the minor tail protein gp15 from the BFK20 bacteriophage. Six fragments containing this SLT domain with adjacent regions of different lengths were cloned, expressed and purified. The biophysical properties of the two best expressing fragments were characterized by nanoDSF and CD spectroscopy, which showed that both fragments had a high refolding ability of 90 %. 3D modeling indicated that the bacteriophage BFK20 SLT domain is structurally similar to lysozyme. The degradation activity of these SLT proteins was evaluated using a lysozyme activity assay. BFK20 might use its transglycosylase activity to allow efficient phage DNA entry into the host cell by degrading bacterial peptidoglycan.
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In 2017, diphtheria outbreaks occurred in several provinces in Indonesia; however, the epidemiological data in the country is limited. The aim of this study was to determine the association between clinical findings and laboratory parameters associated with mortality of children with diphtheria. A retrospective cohort study was conducted at Haji Adam Malik General Hospital, Medan, Indonesia, covering diphtheria patients from January 2020 to December 2023. All patients aged 1-18 years clinically diagnosed with diphtheria were considered eligible. The associations between demographic characteristics, clinical features, immunization status, complications, and laboratory profiles with mortality were determined using Fisher's exact test, and the odds ratio (OR) with a 95% confidence interval (95%CI) was calculated. Our data indicated that the clinical characteristics of myocarditis (p=0.005) and airway obstruction (p=0.003) were associated with mortality. There was also a significant association between thrombocytopenia (p=0.020) and mortality in diphtheria patients. Patients with airway obstruction were 13 times more likely to have an increase in mortality compared to patients without airway obstruction. This study highlights that clinical and laboratory characteristics could be associated with in-hospital mortality of diphtheria cases, and therefore, pediatricians should be aware of the presence of those characteristics to prevent the mortality of the patients.
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Difteria , Mortalidad Hospitalaria , Humanos , Difteria/mortalidad , Difteria/epidemiología , Masculino , Femenino , Niño , Preescolar , Lactante , Estudios Transversales , Adolescente , Estudios Retrospectivos , Indonesia/epidemiología , Miocarditis/mortalidad , Miocarditis/epidemiología , Obstrucción de las Vías Aéreas/mortalidad , Obstrucción de las Vías Aéreas/epidemiología , Trombocitopenia/mortalidad , Trombocitopenia/epidemiologíaRESUMEN
BACKGROUND: Corynebacterium glutamicum is an attractive host for secretory production of recombinant proteins, including high-value industrial enzymes and therapeutic proteins. The choice of an appropriate signaling peptide is crucial for efficient protein secretion. However, due to the limited availability of signal peptides in C. glutamicum, establishing an optimal secretion system is challenging. RESULT: We constructed a signal peptide library for the isolation of target-specific signal peptides and developed a highly efficient secretory production system in C. glutamicum. Based on the sequence information of the signal peptides of the general secretion-dependent pathway in C. glutamicum, a synthetic signal peptide library was designed, and validated with three protein models. First, we examined endoxylanase (XynA) and one potential signal peptide (C1) was successfully isolated by library screening on xylan-containing agar plates. With this C1 signal peptide, secretory production of XynA as high as 3.2 g/L could be achieved with high purity (> 80%). Next, the signal peptide for âº-amylase (AmyA) was screened on a starch-containing agar plate. The production titer of the isolated signal peptide (HS06) reached 1.48 g/L which was 2-fold higher than that of the well-known Cg1514 signal peptide. Finally, we isolated the signal peptide for the M18 single-chain variable fragment (scFv). As an enzyme-independent screening tool, we developed a fluorescence-dependent screening tool using Fluorescence-Activating and Absorption-Shifting Tag (FAST) fusion, and successfully isolated the optimal signal peptide (18F11) for M18 scFv. With 18F11, secretory production as high as 228 mg/L was achieved, which was 3.4-fold higher than previous results. CONCLUSIONS: By screening a fully synthetic signal peptide library, we achieved improved production of target proteins compared to previous results using well-known signal peptides. Our synthetic library provides a useful resource for the development of an optimal secretion system for various recombinant proteins in C. glutamicum, and we believe this bacterium to be a more promising workhorse for the bioindustry.
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Corynebacterium glutamicum , Señales de Clasificación de Proteína , Proteínas Recombinantes , Corynebacterium glutamicum/metabolismo , Corynebacterium glutamicum/genética , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/genética , Biblioteca de Péptidos , Endo-1,4-beta Xilanasas/metabolismo , Endo-1,4-beta Xilanasas/genética , Endo-1,4-beta Xilanasas/biosíntesis , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , alfa-Amilasas/metabolismo , alfa-Amilasas/genéticaRESUMEN
BACKGROUND: Corynebacterium striatum (C. striatum), a common skin and mucosal colonizer, is increasingly considered as an opportunistic pathogen causing bloodstream infections (BSIs). This study aims to investigate the clinical features and outcomes of C. striatum-BSI. METHODS: We included hospitalized cases with C. striatum-positive blood cultures from January 2014 to June 2022 and classified them into C. striatum-BSI group and contamination group; Clinical characteristics, treatments, and outcomes were compared between the C. striatum-BSI group and contamination group, Methicillin-resistant Staphylococcus aureus (MRSA)-BSI and Methicillin-resistant Staphylococcus epidermidis (MRSE)-BSI. RESULTS: Fifty-three patients with positive C. striatum blood cultures were identified. Among them, 25 patients were classified as C. striatum-BSI, with 21 as contamination cases. And 62 cases of MRSA-BSI and 44 cases of MRSE-BSI were identified. Compared to the contaminated group, the C. striatum-BSI group had a shorter time to positivity of blood cultures (27.0 h vs. 42.5 h, P = 0.011). C. striatum-BSI group had a longer time to positivity (27 h) when compared to both the MRSA (20 h) and MRSE groups (19 h) (p < 0.05). Appropriate therapy within 24 h of BSI onset was significantly lower in the C. striatum group (28%) compared to the MRSA (64.5%) and MRSE (65.9%) groups (p < 0.005). The 28-day mortality was higher in the C. striatum group (52.0%) compared to the MRSA (25.8%) and MRSE (18.2%) groups. CONCLUSIONS: Given the distinct characteristics of C. striatum-BSI, including a longer time to positivity than other Gram-positive bacteria and higher mortality rates, we suggest prescribing early appropriate antibiotics if C. striatum-BSI is suspected.
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Bacteriemia , Infecciones por Corynebacterium , Corynebacterium , Staphylococcus aureus Resistente a Meticilina , Humanos , Corynebacterium/aislamiento & purificación , Corynebacterium/clasificación , Corynebacterium/genética , Masculino , Femenino , Persona de Mediana Edad , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Infecciones por Corynebacterium/microbiología , Infecciones por Corynebacterium/tratamiento farmacológico , Bacteriemia/microbiología , Bacteriemia/tratamiento farmacológico , Bacteriemia/mortalidad , Anciano , Staphylococcus epidermidis/aislamiento & purificación , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/mortalidad , Infecciones Estafilocócicas/tratamiento farmacológico , Adulto , Antibacterianos/uso terapéutico , Antibacterianos/farmacología , Estudios Retrospectivos , Anciano de 80 o más AñosRESUMEN
BACKGROUND: Seven-carbon sugars, which rarely exist in nature, are the key constitutional unit of septacidin and hygromycin B in bacteria. These sugars exhibit a potential therapeutic effect for hypoglycaemia and cancer and serve as building blocks for the synthesis of C-glycosides and novel antibiotics. However, chemical and enzymatic approaches for the synthesis of seven-carbon sugars have faced challenges, such as complex reaction steps, low overall yields and high-cost feedstock, limiting their industrial-scale production. RESULTS: In this work, we propose a strain engineering approach for synthesising sedoheptulose using glucose as sole feedstock. The gene pfkA encoding 6-phosphofructokinase in Corynebacterium glutamicum was inactivated to direct the carbon flux towards the pentose phosphate pathway in the cellular metabolic network. This genetic modification successfully enabled the synthesis of sedoheptulose from glucose. Additionally, we identified key enzymes responsible for product formation through transcriptome analysis, and their corresponding genes were overexpressed, resulting in a further 20% increase in sedoheptulose production. CONCLUSION: We achieved a sedoheptulose concentration of 24 g/L with a yield of 0.4 g/g glucose in a 1 L fermenter, marking the highest value up to date. The produced sedoheptulose could further function as feedstock for synthesising structural seven-carbon sugars through coupling with enzymatic isomerisation, epimerisation and reduction reactions.
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Corynebacterium glutamicum , Glucosa , Heptosas , Ingeniería Metabólica , Corynebacterium glutamicum/metabolismo , Corynebacterium glutamicum/genética , Corynebacterium glutamicum/enzimología , Ingeniería Metabólica/métodos , Heptosas/biosíntesis , Heptosas/metabolismo , Glucosa/metabolismo , Vía de Pentosa Fosfato , FermentaciónRESUMEN
Corynebacterium diphtheriae is a multi-drug resistant bacteria responsible for the life-threatening respiratory illness, diphtheria which can lead to severe Nervous system disorders, mainly infecting the lungs, heart, and kidneys if left untreated. In the current study, Corynebacterium diphtheriae MtrA response regulator protein was targeted, which regulates a two-component system of bacterial pathogenesis, and initiates DNA replication and cell division. In the current study a computational approach have been described for drug development against C. diphtheriae infections by inhibiting MtrA protein by small molecules acting as potential inhibitors against it. Molecular docking analysis of the equilibrated MtrA protein revealed compound-0.2970, compound-0.3029, and compound-0.3016 from Asinex Library as the promising inhibitors based on their lowest binding energies (-9.8 kJ/mol, -9.2 kJ/mol, and -8.9 kJ/mol), highest gold scores (40.53, 47.41, and 48.41), drug-likeness and pharmacokinetic properties. The MD simulation studies of the identified top-ranked inhibitors at 100 ns elucidated the system stability and fluctuations in the binding pocket of MtrA protein. Molecular Dynamics Simulations of the top three docked complexes further revealed that the standard binding pocket was retained ensuring the system stability. The rearrangements of H-bonds, van der Waals, pi-pi, and solid hydrophobic interactions were also observed. The binding free energy calculations (MM/PBSA and MM/GBSA) suggested a fundamental binding capability of the ligand to the target receptor MtrA. Therefore, the current study has provided excellent candidates acting as potent inhibitors for developing therapeutic drugs against C. diphtheriae infections. However, in vivo and in vitro animal experiments and accurate clinical trials are needed to validate the potential inhibitory effect of these compounds.
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Porphyrins are intermediate metabolites in the biosynthesis of vital molecules, including heme, cobalamin, and chlorophyll. Bacterial porphyrins are known to be proinflammatory and have been associated with biofilm production. This study investigated porphyrin production by strains of Corynebacterium diphtheriae using emission spectroscopy, high-performance liquid chromatography with fluorescence detection, a diode array detector, and mass spectrometry. Emission spectroscopy revealed characteristic porphyrin emission spectra in all strains, with coproporphyrin III predominating. Qualitative analysis via different chromatography methods revealed identified coproporphyrin III, uroporphyrin I, and protoporphyrin IX in all the strains. Quantitative analysis revealed strain-dependent coproporphyrin III production. More studies are needed to investigate the relationship between porphyrin production and the virulence potential of Corynebacterium diphtheriae.
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Non-diphtheroid Corynebacterium sepsis is rare and has affected only immunocompromised or particularly predisposed patients so far. We present the first case of urosepsis caused by Corynebacterium aurimucosum in a 67-year-old woman, without any known immunodeficiencies and in absence of any immunosuppressive therapy, admitted to the hospital for fever and acute dyspnea. This work suggests a new approach in evaluating the isolation of Corynebacteria, especially if isolated from blood. In particular, it highlights the potential infectious role of C. aurimucosum (often considered a contaminant and only rarely identified as an etiological agent of infections) and its clinical consequences, detailing also interesting aspects about its microbiological diagnosis and relative therapy and clarifying contrasting data of literature.
[Box: see text].
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Infecciones por Corynebacterium , Corynebacterium , Sepsis , Infecciones Urinarias , Humanos , Corynebacterium/aislamiento & purificación , Corynebacterium/genética , Corynebacterium/patogenicidad , Corynebacterium/clasificación , Anciano , Femenino , Infecciones por Corynebacterium/microbiología , Infecciones por Corynebacterium/diagnóstico , Infecciones por Corynebacterium/tratamiento farmacológico , Sepsis/microbiología , Sepsis/tratamiento farmacológico , Infecciones Urinarias/microbiología , Infecciones Urinarias/tratamiento farmacológico , Infecciones Urinarias/diagnóstico , Antibacterianos/uso terapéuticoRESUMEN
Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of liquid l-lysine base produced with a genetically modified strain of Corynebacterium glutamicum as a nutritional feed additive for all animal species. The l-lysine base liquid produced with C. glutamicum NRRL B-67535 and NRRL B-67439 is currently authorised as a nutritional additive for all animal species. The present application is aimed at modifying the current authorisation to include C. glutamicum NRRL B-68248 as a production strain. The new production strain qualifies for the qualified presumption of safety approach when used for production purposes. It was unambiguously identified as C. glutamicum and was shown not to harbour acquired antimicrobial resistance determinants for antibiotics of human and veterinary importance. All the introduced sequences or mutations were considered to be safe, and no viable cells or DNA of the NRRL B-68248 strain was detected in the final product. Therefore, the final product does not pose any safety concern associated with the production strain. l-Lysine base produced using C. glutamicum NRRL B-68248 does not represent a risk for the target species, the consumer or the environment. The additive was considered to be neither irritant to skin or the eyes, nor a dermal sensitiser. l-Lysine base produced with C. glutamicum NRRL B-68248 is considered to be an efficacious source of the essential amino acid l-lysine for non-ruminant animal species. For the supplemental l-lysine to be as efficacious in ruminants as in non-ruminant species, it would require protection against degradation in the rumen.
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Although diphtheria is a vaccine-preventable disease, numerous cases are still reported around the world, as well as outbreaks in countries, including European ones. Species of the Corynebacterium diphtheriae complex are potentially toxigenic and, therefore, must be considered given the possible consequences, such as the circulation of clones and transmission of antimicrobial resistance and virulence genes. Recently, Corynebacterium rouxii was characterized and included among the valid species of the complex. Therefore, two cases of C. rouxii infection arising from infections in domestic animals are presented here. We provide molecular characterization, phylogenetic analyses, genome sequencing, and CRISPR-Cas analyses to contribute to a better understanding of the molecular bases, pathogenesis, and epidemiological monitoring of this species, which is still little studied. We confirmed its taxonomic position with genome sequencing and in silico analysis and identified the ST-918 for both strains. The clinical isolates were sensitive resistance to benzylpenicillin and rifampin. Antimicrobial resistance genes, including tetB, rpoB2, and rbpA genes, were predicted. The bla and ampC genes were not found. Several virulence factors were also detected, including adhesion, iron uptake systems, gene regulation (dtxR), and post-translational modification (MdbA). Finally, one prophage and the Type I-E CRISPR-Cas system were identified.
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Antibacterianos , Infecciones por Corynebacterium , Corynebacterium , Enfermedades de los Perros , Filogenia , Rifampin , Animales , Corynebacterium/genética , Corynebacterium/efectos de los fármacos , Enfermedades de los Perros/microbiología , Perros , Rifampin/farmacología , Infecciones por Corynebacterium/veterinaria , Infecciones por Corynebacterium/microbiología , Antibacterianos/farmacología , Genoma Bacteriano , Farmacorresistencia Bacteriana/genética , Penicilinas/farmacologíaRESUMEN
The iminosugar class of carbohydrate-active enzyme inhibitors has therapeutic applications in metabolic syndrome conditions, viral infections and cancer. Compared to chemical synthesis, microbial iminosugar production has benefits of cost, sustainability and optimization. In this study, the 1-deoxynojirimycin (DNJ) biosynthetic gene cluster from Bacillus velezensis MBLB0692, and its individual genes, were cloned into Corynebacterium glutamicum (Cg). Characterizations of the encoded aminotransferase GabT1, phosphatase Yktc1, and dehydrogenase GutB1, were performed with purified enzymes and whole cell biocatalysts bearing individual and clustered (TYB) genes. GabT1 showed a variable pattern in its half-reaction with a slow turnover. GutB1 was an alkaline dehydrogenase with a broad substrate specificity and no divalent ion dependency while the zinc-dependent phosphatase Yktc1 had substrate specificity that was both pH- and ion-dependent. The CgYktc1 and CgGutB1 whole cells were viable biocatalysts with wider ranges of substrates than their enzyme counterparts. The CgTYB cells produced mannosidase-inhibiting iminosugars corresponding to mannojirimycin dehydrate (162 m/z) and deoxymannojirimycin (164 m/z). Mannosidase inhibitors have been found to be effective in treating orphan diseases, cancer and viral infections, and their biosynthesis by recombinant C. glutamicum can be optimized for industrial production and novel drug development.
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1-Desoxinojirimicina , Bacillus , Corynebacterium glutamicum , Familia de Multigenes , 1-Desoxinojirimicina/química , 1-Desoxinojirimicina/metabolismo , Corynebacterium glutamicum/genética , Corynebacterium glutamicum/metabolismo , Corynebacterium glutamicum/enzimología , Bacillus/genética , Bacillus/enzimología , Manosidasas/genética , Manosidasas/metabolismo , Manosidasas/antagonistas & inhibidores , Iminoazúcares/química , Especificidad por Sustrato , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismoRESUMEN
Gaining a comprehensive understanding of the role played by the oral microbiome in moderate to severe plaque psoriasis and its potential implications for disease management and development holds significant importance. With the objective of exploring correlations between the oral microbiota and severe psoriasis, this study involved 72 severe psoriasis patients and 16 healthy individuals, whose clinical manifestations and living habits were carefully recorded. Cutting-edge techniques such as 16S rRNA gene sequencing and bioinformatics analysis were employed to compare the microbial flora, investigating dynamic changes among severe plaque psoriasis patients, psoriatic arthritis patients and healthy individuals. The findings revealed noteworthy patterns including increased levels of Aggregatibacter in the psoriatic arthritis group, accompanied by a decrease in the level of Prevotella. Moreover, the enrichment o Capnocytandophaga (P = 0.009), Campylobacter (P = 0.0022), and Acetobacter (P = 0.0292) was notably more substantial in the psoriasis group compared to the control group, whereas certain bacterial species such as Bacteroides (P = 0.0049), Muribaculaceae (P = 0.0048) demonstrated decreased enrichment. Additionally, the psoriatic arthritis group exhibited significantly higher levels of Ralstonia, Bifidobacterium and Micromonospora. Based on these findings, it can be inferred that individuals with lower levels of Prevotella and higher levels of Corynebacterium may be more susceptible to psoriasis exacerbation.
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Artritis Psoriásica , Microbiota , Psoriasis , ARN Ribosómico 16S , Humanos , Artritis Psoriásica/microbiología , Femenino , Masculino , Psoriasis/microbiología , Microbiota/genética , Adulto , Persona de Mediana Edad , ARN Ribosómico 16S/genética , Boca/microbiología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Enfermedades de la Uña/microbiología , Estudios de Casos y ControlesRESUMEN
Cardiac implantable electronic device infection in the context of corynebacterial bloodstream infection (BSI) remains poorly understood. From 2012 to 2023 at Mayo Clinic, 4 of 12 patients with corynebacterial BSI had cardiac implantable electronic device infection: 1 patient was diagnosed during a relapsing BSI episode. Undefined source, persistent BSI, and the presence of a prosthetic cardiac valve were common characteristics.
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Corynebacterium glutamicum (C. glutamicum) has become industrially important in producing glutamic acid and lysine since its discovery and has been the subject of proteomics and central carbon metabolism studies. The proteome changes depending on environmental conditions, nutrient availability, and stressors. Post-translational modification (PTMs), such as phosphorylation, methylation, and glycosylation, alter the function and activity of proteins, allowing them to respond quickly to environmental changes. Proteomics techniques, such as mass spectrometry and two-dimensional gel electrophoresis, have enabled the study of proteomes, identification of proteins, and quantification of the expression levels. Understanding proteomes and central carbon metabolism in microorganisms provides insight into their physiology, ecology, and biotechnological applications, such as biofuels, pharmaceuticals, and industrial enzyme production. Several attempts have been made to create efficient production strains to increase productivity in several research fields, such as genomics and proteomics. In addition to amino acids, C. glutamicum is used to produce vitamins, nucleotides, organic acids, and alcohols, expanding its industrial applications. Considerable information has been accumulated, but recent research has focused on proteomes and central carbon metabolism. The development of genetic engineering technologies, such as CRISPR-Cas9, has improved production efficiency by allowing precise manipulation of the metabolic pathways of C. glutamicum. In addition, methods for designing new metabolic pathways and developing customized strains using synthetic biology technology are gradually expanding. This review is expected to enhance the understanding of C. glutamicum and its industrial potential and help researchers identify research topics and design studies.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was the causative agent of the coronavirus disease 2019 (COVID-19) pandemic. While research on COVID-19 has mainly focused on its epidemiology, pathogenesis, and treatment, studies on the naso-oropharyngeal microbiota have emerged in the last few years as an overlooked area of research. Here, we analyzed the bacterial community composition of the naso-oropharynx in 50 suspected SARS-CoV-2 cases (43 detected, 7 not detected) from Veraguas province (Panama) distributed across five age categories. Statistical analysis revealed no significant differences (p < 0.05) in bacterial alpha and beta diversities between the groups categorized by SARS-CoV-2 test results, age, or patient status. The genera Corynebacterium, Staphylococcus, Prevotella, Streptococcus, and Tepidiphilus were the most abundant in both detected and not-detected SARS-CoV-2 group. The linear discriminant analysis effect size (LEfSe) for biomarker exploration indicated that Veillonella and Prevotella were enriched in detected and hospitalized patients with SARS-CoV-2 relative to non-detected patients, while Thermoanaerobacterium and Haemophilus were enriched in non-detected patients with SARS-CoV-2. The results also indicated that the genus Corynebacterium was found to decrease in patients with detected SARS-CoV-2 relative to those with non-detected SARS-CoV-2. Understanding the naso-oropharyngeal microbiota provides insights into the diversity, composition, and resilience of the microbial community in patients with SARS-CoV-2.
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ApxII is a vaccine antigen used to protect against porcine contagious pleuropneumonia, which is a significant threat to the pig industry. Here, we aimed to improve the proteolytic degradation stability of ApxII during its secretion by establishing a complete screening process of stable variants through bioinformatics and site-directed mutagenesis. We employed a combination of semi-rational and rational design strategies to create 34 single-point variants of ApxII. Among them, R114E and T115D variants exhibited better stability without compromising antigen activity. Furthermore, we constructed a multi-site variant, R114E/T115D, which demonstrated the best stability, activity, and yield. Protein stability and molecular dynamic analysis indicated that the greater solubility and lower structural expansion coefficient might explain the increased stability of R114E/T115D. Additionally, site T115 was identified as a key point of truncated ApxII stability. The R114E/T115D variant, with its proven stability and intact antigenic activity, holds promising prospects for industrial-scale applications in the prevention of porcine contagious pleuropneumonia.
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Antígenos Bacterianos , Corynebacterium glutamicum , Mutagénesis Sitio-Dirigida , Estabilidad Proteica , Corynebacterium glutamicum/genética , Corynebacterium glutamicum/metabolismo , Antígenos Bacterianos/genética , Antígenos Bacterianos/metabolismo , Antígenos Bacterianos/inmunología , Antígenos Bacterianos/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Animales , Porcinos , Simulación de Dinámica MolecularRESUMEN
This study focused on improving the flavor quality of seasonings, and enzymatic hydrolysis of soybean protein isolate (SPI) seasoning via traditional technology may lead to undesirable flavors. Herein, we aimed to develop a new type of SPI seasoning through microbial fermentation to improve its flavor quality. The effect of Corynebacterium glutamicum fermentation on the flavoring compounds of seasonings in SPI enzymatic hydrolysate was examined. Sensory evaluation showed that the SPI seasoning had mainly aromatic and roasted flavor, and the response signals of S18 (aromatic compounds), S24 (alcohols and aldehydes), and S25 (esters and ketones) sensors of the electronic nose differed significantly. Overall, 91 volatile compounds were identified via gas chromatography-mass spectrometry. SPI seasonings contained a higher number of alcohols, ketones, aromatics, and heterocyclic compounds than traditional seasonings, which had stronger cheese, fatty, and roasted aromas. According to the relative odor activity value (ROAV) analysis, n-pentylpyrzine, 2,6-dimethylpyrazine, and tetramethylpyrazine are the key flavoring compounds (ROAV ≥ 1) of SPI seasoning, which may impart a unique roasted and meaty aroma. Therefore, the fermentation of SPI enzymatic hydrolysate with C. glutamicum may improve the flavor quality of its products, providing a new method for the development and production of new seasoning products.
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Cases of diphtheria, even in immunized individuals, are still reported in several parts of the world, including in Brazil. New outbreaks occur in Europe and other continents. In this context, studies on Corynebacterium diphtheriae infections are highly relevant, both for a better understanding of the pathogenesis of the disease and for controlling the circulation of clones and antimicrobial resistance genes. Here we present a case of cutaneous infection by multidrug-resistant Corynebacterium diphtheriae and provide its whole-genome sequencing. Genomic analysis revealed resistance genes, including tet(W), sul1, cmx, rpoB2, rbpA and mutation in rpoB. We performed phylogenetic analyzes and used the BRIG to compare the predicted resistance genes with those found in genomes from other significant isolates, including those associated with some outbreaks. Virulence factors such as spaD, srtBC, spaH, srtDE, surface-anchored pilus proteins (sapD), nonfimbrial adhesins (DIP0733, DIP1281, and DIP1621), embC and mptC (putatively involved in CdiLAM), sigA, dtxR and MdbA (putatively involved) in post-translational modification, were detected. We identified the CRISPR-Cas system in our isolate, which was classified as Type II-U based on the database and contains 15 spacers. This system functions as an adaptive immune mechanism. The strain was attributed to a new sequence type ST-928, and phylogenetic analysis confirmed that it was related to ST-634 of C. diphtheriae strains isolated in French Guiana and Brazil. In addition, since infections are not always reported, studies with the sequence data might be a way to complement and inform C. diphtheriae surveillance.
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Sistemas CRISPR-Cas , Corynebacterium diphtheriae , Rifampin , Factores de Virulencia , Corynebacterium diphtheriae/genética , Corynebacterium diphtheriae/patogenicidad , Corynebacterium diphtheriae/efectos de los fármacos , Humanos , Factores de Virulencia/genética , Rifampin/farmacología , Mutación , Filogenia , Difteria/microbiología , Genoma Bacteriano , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana Múltiple/genéticaRESUMEN
Corynebacterium glutamicum was used to ferment wheat gluten hydrolysates (WGHs) to prepare flavour base. This study investigated the effect of hydrolysis degrees (DHs) and fermentation time on flavour of WGHs. During fermentation, the contents of amino nitrogen, total acid and small peptides increased, while the protein and pH value decreased. Succinic acid, GMP, and Glu were the prominent umami substances in fermented WGHs. The aromas of WGHs with different DHs could be distinguished by electronic nose and GC-IMS. Based on OAV of GC-MS, hexanal was the main compound in WGHs, while phenylethyl alcohol and acetoin were dominant after fermentation. WGHs with high DHs accumulated more flavour metabolites. Correlation analysis showed that small peptides (<1 kDa) could promote the formation of flavour substances, and Asp was potentially relevant flavour precursor. This study indicated that fermented WGHs with different DHs can potentially be used in different food applications based on flavour profiles.