scholarly journals Serratia marcescens Quinoprotein Glucose Dehydrogenase Activity Mediates Medium Acidification and Inhibition of Prodigiosin Production by Glucose

2012 ◽  
Vol 78 (17) ◽  
pp. 6225-6235 ◽  
Author(s):  
James E. Fender ◽  
Cody M. Bender ◽  
Nicholas A. Stella ◽  
Roni M. Lahr ◽  
Eric J. Kalivoda ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Serratia Marcescens ◽  
Large Scale ◽  
Transcriptional Control ◽  
Glucose Dehydrogenase ◽  
Model Organism ◽  
Inhibitory Effect ◽  
Biologically Active ◽  
Scale Production ◽  
Content Type

ABSTRACTSerratia marcescensis a model organism for the study of secondary metabolites. The biologically active pigment prodigiosin (2-methyl-3-pentyl-6-methoxyprodiginine), like many other secondary metabolites, is inhibited by growth in glucose-rich medium. Whereas previous studies indicated that this inhibitory effect was pH dependent and did not require cyclic AMP (cAMP), there is no information on the genes involved in mediating this phenomenon. Here we used transposon mutagenesis to identify genes involved in the inhibition of prodigiosin by glucose. Multiple genetic loci involved in quinoprotein glucose dehydrogenase (GDH) activity were found to be required for glucose inhibition of prodigiosin production, including pyrroloquinoline quinone and ubiquinone biosynthetic genes. Upon assessing whether the enzymatic products of GDH activity were involved in the inhibitory effect, we observed thatd-glucono-1,5-lactone andd-gluconic acid, but notd-gluconate, were able to inhibit prodigiosin production. These data support a model in which the oxidation ofd-glucose by quinoprotein GDH initiates a reduction in pH that inhibits prodigiosin production through transcriptional control of the prodigiosin biosynthetic operon, providing new insight into the genetic pathways that control prodigiosin production. Strains generated in this report may be useful in large-scale production of secondary metabolites.

scholarly journals Serratia marcescens Cyclic AMP Receptor Protein Controls Transcription of EepR, a Novel Regulator of Antimicrobial Secondary Metabolites

2015 ◽  
Vol 197 (15) ◽  
pp. 2468-2478 ◽  
Author(s):  
Nicholas A. Stella ◽  
Roni M. Lahr ◽  
Kimberly M. Brothers ◽  
Eric J. Kalivoda ◽  
Kristin M. Hunt ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Secondary Metabolites ◽  
Cyclic Amp ◽  
Serratia Marcescens ◽  
Therapeutic Potential ◽  
Response Regulator ◽  
Biologically Active ◽  
Receptor Protein ◽  
Content Type

ABSTRACTSerratia marcescensgenerates secondary metabolites and secreted enzymes, and it causes hospital infections and community-acquired ocular infections. Previous studies identified cyclic AMP (cAMP) receptor protein (CRP) as an indirect inhibitor of antimicrobial secondary metabolites. Here, we identified a putative two-component regulator that suppressedcrpmutant phenotypes. Evidence supports that the putative response regulatoreepRwas directly transcriptionally inhibited by cAMP-CRP. EepR and the putative sensor kinase EepS were necessary for the biosynthesis of secondary metabolites, including prodigiosin- and serratamolide-dependent phenotypes, swarming motility, and hemolysis. Recombinant EepR bound to the prodigiosin and serratamolide promotersin vitro. Together, these data introduce a novel regulator of secondary metabolites that directly connects the broadly conserved metabolism regulator CRP with biosynthetic genes that may contribute to competition with other microbes.IMPORTANCEThis study identifies a new transcription factor that is directly controlled by a broadly conserved transcription factor, CRP. CRP is well studied in its role to help bacteria respond to the amount of nutrients in their environment. The new transcription factor EepR is essential for the bacteriumSerratia marcescensto produce two biologically active compounds, prodigiosin and serratamolide. These two compounds are antimicrobial and may allowS. marcescensto compete for limited nutrients with other microorganisms. Results from this study tie together the CRP environmental nutrient sensor with a new regulator of antimicrobial compounds. Beyond microbial ecology, prodigiosin and serratamolide have therapeutic potential; therefore, understanding their regulation is important for both applied and basic science.

scholarly journals Plant expression systems for production of hemagglutinin as a vaccine against influenza virus.

2014 ◽  
Vol 61 (3) ◽  
Author(s):  
Patrycja Redkiewicz ◽  
Agnieszka Sirko ◽  
Katarzyna Anna Kamel ◽  
Anna Góra-Sochacka
Keyword(s):  
Influenza Virus ◽  
Large Scale ◽  
Immunological Response ◽  
Biologically Active ◽  
Scale Production ◽  
Expression Systems ◽  
Lethal Challenge ◽  
Subunit Vaccines ◽  
Large Scale Production ◽  
Major Surface

Many examples of a successful application of plant-based expression systems for production of biologically active recombinant proteins exist in the literature. These systems can function as inexpensive platforms for the large scale production of recombinant pharmaceuticals or subunit vaccines. Hemagglutinin (HA) is a major surface antigen of the influenza virus, thus it is in the centre of interests of various subunit vaccine engineering programs. Large scale production of recombinant HA in traditional expression systems, such as mammalian or insect cells, besides other limitations, is expensive and time-consuming. These difficulties stimulate an ever-increasing interest in plant-based production of this recombinant protein. Over the last few years many successful cases of HA production in plants, using both transient and stable expression systems have been reported. Various forms of recombinant HA, including monomers, trimers, virus like particles (VLPs) or chimeric proteins containing its fusion with other polypeptides were obtained and shown to maintain a proper antigenicity. Immunizations of animals (mice, ferrets, rabbits or chickens) with some of these plant-derived hemagglutinin variants were performed, and their effectiveness in induction of immunological response and protection against lethal challenge with influenza virus demonstrated. Plant-produced recombinant subunit vaccines and plant-made VLPs were successfully tested in clinical trials (Phase I and II) that confirmed their tolerance and immunogenicity.

scholarly journals Methyl Jasmonate Induced Oxidative Stress and Accumulation of Secondary Metabolites in Plant Cell and Organ Cultures

2020 ◽  
Vol 21 (3) ◽  
pp. 716 ◽  
Author(s):  
Thanh-Tam Ho ◽  
Hosakatte Niranjana Murthy ◽  
So-Young Park
Keyword(s):  
Secondary Metabolites ◽  
Methyl Jasmonate ◽  
Plant Cell ◽  
Large Scale ◽  
Cultured Cells ◽  
Food Additives ◽  
Plant Secondary Metabolites ◽  
Signal Molecules ◽  
Scale Production ◽  
Organ Cultures

Recently, plant secondary metabolites are considered as important sources of pharmaceuticals, food additives, flavours, cosmetics, and other industrial products. The accumulation of secondary metabolites in plant cell and organ cultures often occurs when cultures are subjected to varied kinds of stresses including elicitors or signal molecules. Application of exogenous jasmonic acid (JA) and methyl jasmonate (MJ) is responsible for the induction of reactive oxygen species (ROS) and subsequent defence mechanisms in cultured cells and organs. It is also responsible for the induction of signal transduction, the expression of many defence genes followed by the accumulation of secondary metabolites. In this review, the application of exogenous MJ elicitation strategies on the induction of defence mechanism and secondary metabolite accumulation in cell and organ cultures is introduced and discussed. The information presented here is useful for efficient large-scale production of plant secondary metabolites by the plant cell and organ cultures.

scholarly journals Blakeslea trispora Photoreceptors: Identification and Functional Analysis

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Wei Luo ◽  
Chao Xue ◽  
Yuzheng Zhao ◽  
Huili Zhang ◽  
Zhiming Rao ◽  
...  
Keyword(s):  
Large Scale ◽  
Binding Domain ◽  
Site Directed Mutagenesis ◽  
Flavin Mononucleotide ◽  
Blakeslea Trispora ◽  
Scale Production ◽  
Bioinformatics Analyses ◽  
Content Type ◽  
Flavin Binding

ABSTRACT Blakeslea trispora is an industrial fungal species used for large-scale production of carotenoids. However, B. trispora light-regulated physiological processes, such as carotenoid biosynthesis and phototropism, are not fully understood. In this study, we isolated and characterized three photoreceptor genes, btwc-1a, btwc-1b, and btwc-1c, in B. trispora. Bioinformatics analyses of these genes and their protein sequences revealed that the functional domains (PAS/LOV [Per-ARNT-Sim/light-oxygen-voltage] domain and zinc finger structure) of the proteins have significant homology to those of other fungal blue-light regulator proteins expressed by Mucor circinelloides and Neurospora crassa. The photoreceptor proteins were synthesized by heterologous expression in Escherichia coli. The chromogenic groups consisting of flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) were detected to accompany BTWC-1 proteins by using high-performance liquid chromatography (HPLC) and fluorescence spectrometry, demonstrating that the proteins may be photosensitive. The absorbance changes of the purified BTWC-1 proteins seen under dark and light conditions indicated that they were light responsive and underwent a characteristic photocycle by light induction. Site-directed mutagenesis of the cysteine residual (Cys) in BTWC-1 did not affect the normal expression of the protein in E. coli but did lead to the loss of photocycle response, indicating that Cys represents a flavin-binding domain for photon detection. We then analyzed the functions of BTWC-1 proteins by complementing btwc-1a, btwc-1b, and btwc-1c into the counterpart knockout strains of M. circinelloides for each mcwc-1 gene. Transformation of the btwc-1a complement into mcwc-1a knockout strains restored the positive phototropism, while the addition of btwc-1c complement remedied the deficiency of carotene biosynthesis in the mcwc-1c knockout strains under conditions of illumination. These results indicate that btwc-1a and btwc-1c are involved in phototropism and light-inducible carotenogenesis. Thus, btwc-1 genes share a conserved flavin-binding domain and act as photoreceptors for control of different light transduction pathways in B. trispora. IMPORTANCE Studies have confirmed that light-regulated carotenogenesis is prevalent in filamentous fungi, especially in mucorales. However, few investigations have been done to understand photoinduced synthesis of carotenoids and related mechanisms in B. trispora, a well-known industrial microbial strains. In the present study, three photoreceptor genes in B. trispora were cloned, expressed, and characterized by bioinformatics and photoreception analyses, and then in vivo functional analyses of these genes were constructed in M. circinelloides. The results of this study will lead to a better understanding of photoreception and light-regulated carotenoid synthesis and other physiological responses in B. trispora.

scholarly journals AraR, an l-Arabinose-Responsive Transcriptional Regulator in Corynebacterium glutamicum ATCC 31831, Exerts Different Degrees of Repression Depending on the Location of Its Binding Sites within the Three Target Promoter Regions

2015 ◽  
Vol 197 (24) ◽  
pp. 3788-3796 ◽  
Author(s):  
Takayuki Kuge ◽  
Haruhiko Teramoto ◽  
Masayuki Inui
Keyword(s):  
Corynebacterium Glutamicum ◽  
Binding Sites ◽  
Large Scale ◽  
Transcriptional Regulator ◽  
Scale Production ◽  
Primary Role ◽  
Promoter Regions ◽  
Independent Manner ◽  
Content Type

ABSTRACTInCorynebacterium glutamicumATCC 31831, a LacI-type transcriptional regulator AraR, represses the expression ofl-arabinose catabolism (araBDA), uptake (araE), and the regulator (araR) genes clustered on the chromosome. AraR binds to three sites: one (BSB) between the divergent operons (araBDAandgalM-araR) and two (BSE1and BSE2) upstream ofaraE.l-Arabinose acts as an inducer of the AraR-mediated regulation. Here, we examined the roles of these AraR-binding sites in the expression of the AraR regulon. BSBmutation resulted in derepression of botharaBDAandgalM-araRoperons. The effects of BSE1and/or BSE2mutation onaraEexpression revealed that the two sites independently function as theciselements, but BSE1plays the primary role. However, AraR was shown to bind to these sites with almost the same affinityin vitro. Taken together, the expression ofaraBDAandaraEis strongly repressed by binding of AraR to a single site immediately downstream of the respective transcriptional start sites, whereas the binding site overlapping the −10 or −35 region of thegalM-araRandaraEpromoters is less effective in repression. Furthermore, downregulation ofaraBDAandaraEdependent onl-arabinose catabolism observed in the BSBmutant and the AraR-independentaraRpromoter identified withingalM-araRadd complexity to regulation of the AraR regulon derepressed byl-arabinose.IMPORTANCECorynebacterium glutamicumhas a long history as an industrial workhorse for large-scale production of amino acids. An important aspect of industrial microorganisms is the utilization of the broad range of sugars for cell growth and production process. MostC. glutamicumstrains are unable to use a pentose sugarl-arabinose as a carbon source. However, genes forl-arabinose utilization and its regulation have been recently identified inC. glutamicumATCC 31831. This study elucidates the roles of the multiple binding sites of the transcriptional repressor AraR in the derepression byl-arabinose and thereby highlights the complex regulatory feedback loops in combination withl-arabinose catabolism-dependent repression of the AraR regulon in an AraR-independent manner.

scholarly journals 300-Fold Increase in Production of the Zn2+-Dependent Dechlorinase TrzN in Soluble Form via Apoenzyme Stabilization

2014 ◽  
Vol 80 (13) ◽  
pp. 4003-4011 ◽  
Author(s):  
Colin J. Jackson ◽  
Christopher W. Coppin ◽  
Paul D. Carr ◽  
Alexey Aleksandrov ◽  
Matthew Wilding ◽  
...  
Keyword(s):  
Soluble Protein ◽  
Metal Ion ◽  
Large Scale ◽  
Computational Simulation ◽  
Active Form ◽  
Fold Increase ◽  
Soluble Form ◽  
Scale Production ◽  
Content Type ◽  
The Stability

ABSTRACTMicrobial metalloenzymes constitute a large library of biocatalysts, a number of which have already been shown to catalyze the breakdown of toxic chemicals or industrially relevant chemical transformations. However, while there is considerable interest in harnessing these catalysts for biotechnology, for many of the enzymes, their large-scale production in active, soluble form in recombinant systems is a significant barrier to their use. In this work, we demonstrate that as few as three mutations can result in a 300-fold increase in the expression of soluble TrzN, an enzyme fromArthrobacter aurescenswith environmental applications that catalyzes the hydrolysis of triazine herbicides, inEscherichia coli. Using a combination of X-ray crystallography, kinetic analysis, and computational simulation, we show that the majority of the improvement in expression is due to stabilization of the apoenzyme rather than the metal ion-bound holoenzyme. This provides a structural and mechanistic explanation for the observation that many compensatory mutations can increase levels of soluble-protein production without increasing the stability of the final, active form of the enzyme. This study provides a molecular understanding of the importance of the stability of metal ion free states to the accumulation of soluble protein and shows that differences between apoenzyme and holoenzyme structures can result in mutations affecting the stability of either state differently.

scholarly journals Population Pharmacokinetic and Pharmacodynamic Modeling of Amodiaquine and Desethylamodiaquine in Women with Plasmodium vivax Malaria during and after Pregnancy

2012 ◽  
Vol 56 (11) ◽  
pp. 5764-5773 ◽  
Author(s):  
Joel Tarning ◽  
Palang Chotsiri ◽  
Vincent Jullien ◽  
Marcus J. Rijken ◽  
Martin Bergstrand ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Plasmodium Vivax ◽  
Plasma Concentrations ◽  
Inhibitory Effect ◽  
Biologically Active ◽  
Pharmacodynamic Modeling ◽  
Population Pharmacokinetic ◽  
Content Type ◽  
Plasmodium Vivax Malaria

ABSTRACTAmodiaquine is effective for the treatment ofPlasmodium vivaxmalaria, but there is little information on the pharmacokinetic and pharmacodynamic properties of amodiaquine in pregnant women with malaria. This study evaluated the population pharmacokinetic and pharmacodynamic properties of amodiaquine and its biologically active metabolite, desethylamodiaquine, in pregnant women withP. vivaxinfection and again after delivery. Twenty-seven pregnant women infected withP. vivaxmalaria on the Thai-Myanmar border were treated with amodiaquine monotherapy (10 mg/kg/day) once daily for 3 days. Nineteen women, with and withoutP. vivaxinfections, returned to receive the same amodiaquine dose postpartum. Nonlinear mixed-effects modeling was used to evaluate the population pharmacokinetic and pharmacodynamic properties of amodiaquine and desethylamodiaquine. Amodiaquine plasma concentrations were described accurately by lagged first-order absorption with a two-compartment disposition model followed by a three-compartment disposition of desethylamodiaquine under the assumption of completein vivoconversion. Body weight was implemented as an allometric function on all clearance and volume parameters. Amodiaquine clearance decreased linearly with age, and absorption lag time was reduced in pregnant patients. Recurrent malaria infections in pregnant women were modeled with a time-to-event model consisting of a constant-hazard function with an inhibitory effect of desethylamodiaquine. Amodiaquine treatment reduced the risk of recurrent infections from 22.2% to 7.4% at day 35. In conclusion, pregnancy did not have a clinically relevant impact on the pharmacokinetic properties of amodiaquine or desethylamodiaquine. No dose adjustments are required in pregnancy.

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