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Microbial Cell Factories Aug 2019Roseoflavin, a promising broad-spectrum antibiotic, is naturally produced by the bacteria Streptomyces davaonensis and Streptomyces cinnabarinus. The key enzymes...
BACKGROUND
Roseoflavin, a promising broad-spectrum antibiotic, is naturally produced by the bacteria Streptomyces davaonensis and Streptomyces cinnabarinus. The key enzymes responsible for roseoflavin biosynthesis and the corresponding genes were recently identified. In this study we aimed to enhance roseoflavin production in S. davaonensis and to synthesize roseoflavin in the heterologous hosts Bacillus subtilis and Corynebacterium glutamicum by (over)expression of the roseoflavin biosynthesis genes.
RESULTS
While expression of the roseoflavin biosynthesis genes from S. davaonensis was not observed in recombinant strains of B. subtilis, overexpression was successful in C. glutamicum and S. davaonensis. Under the culture conditions tested, a maximum of 1.6 ± 0.2 µM (ca. 0.7 mg/l) and 34.9 ± 5.2 µM (ca. 14 mg/l) roseoflavin was produced with recombinant strains of C. glutamicum and S. davaonensis, respectively. In S. davaonensis the roseoflavin yield was increased by 78%.
CONCLUSIONS
The results of this study provide a sound basis for the development of an economical roseoflavin production process.
Topics: Anti-Bacterial Agents; Bacillus subtilis; Corynebacterium glutamicum; Metabolic Engineering; Riboflavin; Streptomyces
PubMed: 31451111
DOI: 10.1186/s12934-019-1181-2 -
CMAJ : Canadian Medical Association... Oct 2021
Topics: Administration, Topical; Anti-Bacterial Agents; Antifungal Agents; Axilla; Ciclopirox; Corynebacterium; Diagnosis, Differential; Erythrasma; Erythromycin; Groin; Humans; Male; Middle Aged; Mycoses; Treatment Outcome
PubMed: 34607848
DOI: 10.1503/cmaj.210310 -
Sheng Wu Gong Cheng Xue Bao = Chinese... May 2021Fermentative production of amino acids is one of the pillars of the fermentation industry in China. Recently, with the fast development of metabolic engineering and... (Review)
Review
Fermentative production of amino acids is one of the pillars of the fermentation industry in China. Recently, with the fast development of metabolic engineering and synthetic biology technologies, the metabolic engineering for production of amino acids has been flourishing. Conventional forward metabolic engineering, reversed metabolic engineering based on omics data and in silico simulation, and evolutionary metabolic engineering mimicking the natural evolution, have shown increasingly promising applications. A series of highly efficient and robust amino acids-producing strains have been developed and applied in the industrial production of amino acids. The increasingly fierce market competition has put forward new requirements for strain breeding and selection, such as developing high value-added amino acids, dynamic regulation of cellular metabolism, and adapting to the requirements of new process. This review summarizes the advances and prospects in metabolic engineering for the production of amino acids.
Topics: Amino Acids; China; Corynebacterium glutamicum; Metabolic Engineering; Synthetic Biology
PubMed: 34085449
DOI: 10.13345/j.cjb.200588 -
Journal of Infection in Developing... Jun 2022Toxigenic Corynebacterium diphtheriae causes classical diphtheria. Skin infections by toxigenic or non-toxigenic Corynebacterium diphtheriae are prevalent in the tropics...
INTRODUCTION
Toxigenic Corynebacterium diphtheriae causes classical diphtheria. Skin infections by toxigenic or non-toxigenic Corynebacterium diphtheriae are prevalent in the tropics but are rarely reported.
CASE PRESENTATION
We report the identification of a non-toxigenic Corynebacterium diphtheriae (biovar Gravis) isolate in a 52-year-old Cambodian male. The patient presented purulent and non-healing ulcerations on the right hallux. The wound has healed after 7 days of antibiotic therapy with a favourable outcome.
CONCLUSIONS
This case represents, to our knowledge, the first report of Corynebacterium diphtheriae in Cambodia in the last 10 years, and highlights the lack of diagnosis and notifications of diphtheria. It is important to raise awareness among clinicians and to set up diphtheria surveillance in Cambodia.
Topics: Corynebacterium; Corynebacterium Infections; Corynebacterium diphtheriae; Diphtheria; Hallux; Humans; Male; Middle Aged
PubMed: 35797309
DOI: 10.3855/jidc.16153 -
Microbial Cell Factories Dec 2021Branched chain amino acids (BCAAs) are widely applied in the food, pharmaceutical, and animal feed industries. Traditional chemical synthetic and enzymatic BCAAs... (Review)
Review
BACKGROUND
Branched chain amino acids (BCAAs) are widely applied in the food, pharmaceutical, and animal feed industries. Traditional chemical synthetic and enzymatic BCAAs production in vitro has been hampered by expensive raw materials, harsh reaction conditions, and environmental pollution. Microbial metabolic engineering has attracted considerable attention as an alternative method for BCAAs biosynthesis because it is environmentally friendly and delivers high yield.
MAIN TEXT
Corynebacterium glutamicum (C. glutamicum) possesses clear genetic background and mature gene manipulation toolbox, and has been utilized as industrial host for producing BCAAs. Acetohydroxy acid synthase (AHAS) is a crucial enzyme in the BCAAs biosynthetic pathway of C. glutamicum, but feedback inhibition is a disadvantage. We therefore reviewed AHAS modifications that relieve feedback inhibition and then investigated the importance of AHAS modifications in regulating production ratios of three BCAAs. We have comprehensively summarized and discussed metabolic engineering strategies to promote BCAAs synthesis in C. glutamicum and offer solutions to the barriers associated with BCAAs biosynthesis. We also considered the future applications of strains that could produce abundant amounts of BCAAs.
CONCLUSIONS
Branched chain amino acids have been synthesized by engineering the metabolism of C. glutamicum. Future investigations should focus on the feedback inhibition and/or transcription attenuation mechanisms of crucial enzymes. Enzymes with substrate specificity should be developed and applied to the production of individual BCAAs. The strategies used to construct strains producing BCAAs provide guidance for the biosynthesis of other high value-added compounds.
Topics: Acetolactate Synthase; Amino Acids, Branched-Chain; Bacterial Proteins; Biosynthetic Pathways; Corynebacterium glutamicum; Feedback, Physiological; Fermentation; Metabolic Engineering; Substrate Specificity
PubMed: 34952576
DOI: 10.1186/s12934-021-01721-0 -
Journal of Microbiology and... Nov 2021Violacein, a purple pigment first isolated from a gram-negative coccobacillus , has gained extensive research interest in recent years due to its huge potential in the... (Review)
Review
Violacein, a purple pigment first isolated from a gram-negative coccobacillus , has gained extensive research interest in recent years due to its huge potential in the pharmaceutic area and industry. In this review, we summarize the latest research advances concerning this pigment, which include (1) fundamental studies of its biosynthetic pathway, (2) production of violacein by native producers, apart from , (3) metabolic engineering for improved production in heterologous hosts such as , , and , (4) biological/pharmaceutical and industrial properties, (5) and applications in synthetic biology. Due to the intrinsic properties of violacein and the intermediates during its biosynthesis, the prospective research has huge potential to move this pigment into real clinical and industrial applications.
Topics: Biosynthetic Pathways; Chromobacterium; Citrobacter freundii; Corynebacterium glutamicum; Escherichia coli; Indoles; Industrial Microbiology; Metabolic Engineering; Molecular Structure; Yarrowia
PubMed: 34584039
DOI: 10.4014/jmb.2107.07045 -
The Lancet. Microbe Jan 2024
Topics: Humans; Diphtheria; Nigeria; Corynebacterium diphtheriae; Corynebacterium; Disease Outbreaks
PubMed: 37951229
DOI: 10.1016/S2666-5247(23)00330-0 -
Journal of Clinical Microbiology Nov 2020
Topics: Corynebacterium Infections; Corynebacterium diphtheriae; Diphtheria; Humans
PubMed: 33208528
DOI: 10.1128/JCM.00506-20 -
Vaccine Jul 2022The objective of this study was to evaluate the safety of prenatal tetanus, diphtheria, acellular pertussis (Tdap) vaccination. This cohort study was conducted among...
The objective of this study was to evaluate the safety of prenatal tetanus, diphtheria, acellular pertussis (Tdap) vaccination. This cohort study was conducted among pregnant members at Kaiser Permanente Southern California (KPSC). The exposed cohort consisted of women who received Tdap vaccine on or after the 27th week of pregnancy between January 2018 and January 2019. The unexposed cohort consisted of matched women who were pregnant between January 2012 and December 2014 and were not vaccinated with any Tdap vaccine throughout their pregnancy. Maternal and infant characteristics and pre-specified endpoints were collected through automated data and review of the electronic health records. Unadjusted and adjusted relative risks (aRRs) with confidence intervals (CIs) were estimated by Poisson regression. Non-inferiority testing (i.e., to rule out a two-fold increase) was conducted for primary endpoints with adjustment for multiplicity. Superiority testing was conducted without multiplicity adjustment for secondary endpoints. The analysis consisted of 16,606 pairs of Tdap recipients and unexposed pregnant women. For the primary endpoints, the aRR for preeclampsia/eclampsia was 1.38 (98.75% CI:1.21-1.58) and the aRR for intrauterine infection was 1.28 (98.75% CI:1.12-1.47). These increases were consistent with the background increasing trend of these diagnoses among all pregnant women at KPSC since 2011, and the upper limit of the 98.75% CI of both aRRs did not exceed the pre-specified threshold of 2. No increased risks of small for gestational age (aRR = 1.04, 98.75% CI:0.94-1.16) or preterm delivery (aRR = 0.71, 98.75% CI:0.64-0.78) were observed. No evidence of increased risks for secondary endpoints, including poor fetal growth, preterm pre-labor rupture of membranes, stillbirth/fetal death, placental abruption, transfusion during delivery hospitalization, and neonatal death, was observed. Prenatal Tdap vaccination after the 27th week of pregnancy was not associated with increased risks of pre-specified maternal and infant outcomes, supporting the safety of Tdap vaccination during pregnancy.
Topics: Cohort Studies; Corynebacterium; Diphtheria; Diphtheria-Tetanus-acellular Pertussis Vaccines; Female; Humans; Infant; Infant, Newborn; Placenta; Pregnancy; Retrospective Studies; Tetanus; Vaccination; Whooping Cough
PubMed: 35717267
DOI: 10.1016/j.vaccine.2022.06.009 -
Microbiome Jun 2023Bacteria colonizing the nasopharynx play a key role as gatekeepers of respiratory health. Yet, dynamics of early life nasopharyngeal (NP) bacterial profiles remain...
BACKGROUND
Bacteria colonizing the nasopharynx play a key role as gatekeepers of respiratory health. Yet, dynamics of early life nasopharyngeal (NP) bacterial profiles remain understudied in low- and middle-income countries (LMICs), where children have a high prevalence of risk factors for lower respiratory tract infection. We investigated longitudinal changes in NP bacterial profiles, and associated exposures, among healthy infants from low-income households in South Africa.
METHODS
We used short fragment (V4 region) 16S rRNA gene amplicon sequencing to characterize NP bacterial profiles from 103 infants in a South African birth cohort, at monthly intervals from birth through the first 12 months of life and six monthly thereafter until 30 months.
RESULTS
Corynebacterium and Staphylococcus were dominant colonizers at 1 month of life; however, these were rapidly replaced by Moraxella- or Haemophilus-dominated profiles by 4 months. This succession was almost universal and largely independent of a broad range of exposures. Warm weather (summer), lower gestational age, maternal smoking, no day-care attendance, antibiotic exposure, or low height-for-age z score at 12 months were associated with higher alpha and beta diversity. Summer was also associated with higher relative abundances of Staphylococcus, Streptococcus, Neisseria, or anaerobic gram-negative bacteria, whilst spring and winter were associated with higher relative abundances of Haemophilus or Corynebacterium, respectively. Maternal smoking was associated with higher relative abundances of Porphyromonas. Antibiotic therapy (or isoniazid prophylaxis for tuberculosis) was associated with higher relative abundance of anerobic taxa (Porphyromonas, Fusobacterium, and Prevotella) and with lower relative abundances of health associated-taxa Corynebacterium and Dolosigranulum. HIV-exposure was associated with higher relative abundances of Klebsiella or Veillonella and lower relative abundances of an unclassified genus within the family Lachnospiraceae.
CONCLUSIONS
In this intensively sampled cohort, there was rapid and predictable replacement of early profiles dominated by health-associated Corynebacterium and Dolosigranulum with those dominated by Moraxella and Haemophilus, independent of exposures. Season and antibiotic exposure were key determinants of NP bacterial profiles. Understudied but highly prevalent exposures prevalent in LMICs, including maternal smoking and HIV-exposure, were associated with NP bacterial profiles. Video Abstract.
Topics: Infant; Child; Humans; Infant, Newborn; South Africa; Birth Cohort; RNA, Ribosomal, 16S; Nasopharynx; Microbiota; Bacteria; Moraxella; Corynebacterium; Anti-Bacterial Agents; HIV Infections
PubMed: 37271810
DOI: 10.1186/s40168-023-01563-5