scholarly journals Co-inducible catabolism of 1-naphthol via synergistic regulation of the initial hydroxylase genes in Sphingobium sp. strain B2

2021 ◽  
Author(s):  
Junwei Huang ◽  
Dian Chen ◽  
Xiangkun Kong ◽  
Shurui Wu ◽  
Kai Chen ◽  
...  
Keyword(s):  
Carbon Source ◽  
Organic Pollutant ◽  
Carbon Sources ◽  
Transcriptional Regulators ◽  
Raw Material ◽  
Toxic Compound ◽  
Catabolic Genes ◽  
Growth Substrates ◽  
Synergistic Regulation ◽  
Metabolic Mechanism

1-Naphthol, a widely used raw material for organic synthesis, is also a well-known organic pollutant. Due to its high toxicity, 1-naphthol is rarely used by microorganisms as the sole carbon source for growth. In this study, catabolism of 1-naphthol by Sphingobium sp. strain B2 was found to be greatly enhanced by additional supplementation with primary carbon sources (e.g., glucose, maltose and sucrose), and 1-naphthol was even used as the carbon source for growth when strain B2 cells had been pre-induced by both 1-naphthol and glucose. A distinct two-component flavin-dependent monooxygenase NdcA1A2 was found to be responsible for the initial hydroxylation of 1-naphthol to 1,2-dihydroxynaphthalene, a more toxic compound. Transcriptional levels of ndcA1A2 genes were significantly up-regulated when strain B2 cells were cultured with both 1-naphthol and glucose as compared to cells cultured with sole 1-naphthol or glucose. Two transcriptional regulators, the activator NdcS and the inhibitor NdcR were found to play key roles in the synergistic regulation of the transcription of the 1-naphthol initial catabolic genes ndcA1A2. Importance Co-metabolism is a widely observed phenomenon, especially in the field of microbial catabolism of highly toxic xenobiotics. However, the mechanisms of co-metabolism are ambiguous and the roles of the obligately co-existing growth substrates remain largely unknown. In this study, we revealed that the roles of the co-existing primary carbon sources (e.g. glucose) in the enhanced catabolism of the toxic compound 1-naphthol in Sphingobium sp. strain B2 was not solely because they were used as growth substrates to support cell growth, but more importantly they acted as “co-inducers” to interact with two transcriptional regulators, the activator NdcS and the inhibitor NdcR, to synergistically regulate the transcription of the 1-naphthol initial catabolic genes ndcA1A2. Our findings provide new insights into the co-metabolic mechanism of highly toxic compounds in microorganisms.

scholarly journals Process Design and Economics of On-Site Cellulase Production on Various Carbon Sources in a Softwood-Based Ethanol Plant

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Zsolt Barta ◽  
Krisztina Kovacs ◽  
Kati Reczey ◽  
Guido Zacchi
Keyword(s):  
Carbon Source ◽  
Enzyme Production ◽  
Ethanol Yield ◽  
Liquid Fraction ◽  
Carbon Sources ◽  
Cellulase Production ◽  
Raw Material ◽  
Steam Pretreatment ◽  
Whole Process ◽  
Feasible Alternative

On-site cellulase enzyme fermentation in a softwood-to-ethanol process, based on SO2-catalysed steam pretreatment followed by simultaneous saccharification and fermentation, was investigated from a techno-economic aspect using Aspen Plus© and Aspen Icarus Process Evaluator© softwares. The effect of varying the carbon source of enzyme fermentation, at constant protein and mycelium yields, was monitored through the whole process. Enzyme production step decreased the overall ethanol yield (270 L/dry tonne of raw material in the case of purchased enzymes) by 5–16 L/tonne. Capital cost was found to be the main cost contributor to enzyme fermentation, constituting to 60–78% of the enzyme production cost, which was in the range of 0.42–0.53 SEK/L ethanol. The lowest minimum ethanol selling prices (4.71 and 4.82 SEK/L) were obtained in those scenarios, where pretreated liquid fraction supplemented with molasses was used as carbon source. In some scenarios, on-site enzyme fermentation was found to be a feasible alternative.

scholarly journals Towards Net Zero Greenhouse Gas Emissions in the Energy and Chemical Sectors in Switzerland and Beyond – A Review

2021 ◽  
Vol 75 (9) ◽  
pp. 788-799
Author(s):  
Simone Brethauer ◽  
Michael Hans-Peter Studer
Keyword(s):  
Renewable Energy ◽  
Carbon Source ◽  
Energy Demand ◽  
Nuclear Power ◽  
Carbon Sources ◽  
Energy System ◽  
Heat Pumps ◽  
Raw Material ◽  
Oil Demand ◽  
Current Energy

In today's societies, climate-damaging and finite fossil resources such as oil and natural gas serve a dual purpose as energy source and as carbon source for chemicals and plastics. To respond to the finite availability and to meet international climate goals, a change to a renewable energy and raw material basis is inevitable and represents a highly complex task. In this review, we assess possible technology paths for Switzerland to reach these goals. First, we provide an overview of Switzerland's current energy demand and discuss possible renewable technologies as well as proposed scenarios to defossilize the current energy system. In here, electric vehicles and heat pumps are key technologies, whereas mainly photovoltaics replace nuclear power to deliver clean electricity. The production of chemicals also consumes fossil resources and for Switzerland, the oil demand for imported domestically used chemicals and plastics corresponds to around 20% of the current energetic oil demand. Thus, we additionally summarize technologies and visions for a sustainable chemical sector based on the renewable carbon sources biomass, CO2 and recycled plastic. As biomass is the most versatile renewable energy and carbon source, although with a limited availability, aspects and proposed strategies for an optimal use are discussed.

Effect of carbon source on Phenobarbital metabolism by Rhizopus stolonifer

2010 ◽  
Vol 3 (2) ◽  
pp. 1022-1027
Author(s):  
Kavitha K ◽  
Asha S ◽  
Hima Bindu T.V.L ◽  
Vidyavathi M
Keyword(s):  
Carbon Source ◽  
High Performance ◽  
Carbon Sources ◽  
In Vitro Models ◽  
Rhizopus Stolonifer ◽  
Safety And Efficacy ◽  
Alternative Systems ◽  
Toxicological Studies ◽  
Microbial Model

The safety and efficacy of a drug is based on its metabolism or metabolite formed. The metabolism of drugs can be studied by different in vitro models, among which microbial model became popular. In the present study, eight microbes were screened for their ability to metabolize phenobarbital in a manner comparable to humans with a model to develop alternative systems to study human drug metabolism. Among the different microbes screened, a filamentous fungi Rhizopus stolonifer metabolized phenobarbital to its metabolite which is used for further pharmacological and toxicological studies. The transformation of phenobarbital was identified by high- performance liquid chromatography (HPLC). Interestingly, Rhizopus stolonifer sample showed an extra metabolite peak at 3.11min. compared to its controls. The influence of different carbon sources in media used for growth of fungus, on metabolite production was studied, to find its effect in production of metabolite as the carbon source may influence the growth of the cell.

scholarly journals Denitrification Control in a Recirculating Aquaculture System—A Simulation Study

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1306
Author(s):  
Pedro Almeida ◽  
Laurent Dewasme ◽  
Alain Vande Wouwer
Keyword(s):  
Carbon Source ◽  
Carbon Sources ◽  
Aquatic Organisms ◽  
Operating Conditions ◽  
Toxic Substances ◽  
Recirculating Aquaculture System ◽  
Treatment Technology ◽  
Tuning Method ◽  
Recirculating Aquaculture ◽  
Aquaculture System

The recirculating aquaculture system (RAS) is a land-based water treatment technology, which allows for farming aquatic organisms, such as fish, by reusing the water in the production (often less than 5%). This technology is based on the use of filters, either mechanical or biological, and can, in principle, be used for any species grown in aquaculture. Due to the low recirculation rate, ammonia accumulates in the system and must be converted into nitrate using nitrification reactors. Although less toxic for fish, nitrate can also be further reduced into nitrogen gas by the use of denitrification biofilters which may create several issues, such as incomplete denitrification, resulting in toxic substances, such as nitrite and nitric oxide, or a waste of carbon source in excess. Control of the added quantity of carbon source in the denitrification biofilter is then mandatory to keep nitrate/nitrite concentrations under toxic levels for fish and in accordance with local effluent regulations, and to reduce costs related to wasted organic carbon sources. This study therefore investigates the application of different control methodologies to a denitrification reactor in a RAS. To this end, a numerical simulator is built to predict the RAS behavior and to allow for the comparison of different control approaches, in the presence of changes in the operating conditions, such as fish density and biofilter removal efficiency. First, a classical proportional-integral-derivative (PID) controller was designed, based on an SIMC tuning method depending on the amount of ammonia excreted by fish. Then, linearizing and cascade controllers were considered as possible alternatives.

scholarly journals The carbon source-dependent pattern of antimicrobial activity and gene expression in Pseudomonas donghuensis P482

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Matuszewska ◽  
Tomasz Maciąg ◽  
Magdalena Rajewska ◽  
Aldona Wierzbicka ◽  
Sylwia Jafra
Keyword(s):  
Gene Expression ◽  
Antimicrobial Activity ◽  
Carbon Source ◽  
Reference Genes ◽  
Plant Pathogens ◽  
Plant Protection ◽  
Carbon Sources ◽  
Unknown Compound ◽  
Fungal Plant Pathogens ◽  
The Impact

AbstractPseudomonas donghuensis P482 is a tomato rhizosphere isolate with the ability to inhibit growth of bacterial and fungal plant pathogens. Herein, we analysed the impact of the carbon source on the antibacterial activity of P482 and expression of the selected genes of three genomic regions in the P482 genome. These regions are involved in the synthesis of pyoverdine, 7-hydroxytropolone (7-HT) and an unknown compound (“cluster 17”) and are responsible for the antimicrobial activity of P482. We showed that the P482 mutants, defective in these regions, show variations and contrasting patterns of growth inhibition of the target pathogen under given nutritional conditions (with glucose or glycerol as a carbon source). We also selected and validated the reference genes for gene expression studies in P. donghuensis P482. Amongst ten candidate genes, we found gyrB, rpoD and mrdA the most stably expressed. Using selected reference genes in RT-qPCR, we assessed the expression of the genes of interest under minimal medium conditions with glucose or glycerol as carbon sources. Glycerol was shown to negatively affect the expression of genes necessary for 7-HT synthesis. The significance of this finding in the light of the role of nutrient (carbon) availability in biological plant protection is discussed.

Development of mutants of Gliocladium virens tolerant to benomyl

1990 ◽  
Vol 36 (7) ◽  
pp. 484-489 ◽  
Author(s):  
G. C. Papavizas ◽  
D. P. Roberts ◽  
K. K. Kim
Keyword(s):  
Carbon Source ◽  
Type Strain ◽  
Wild Type Strain ◽  
Carbon Sources ◽  
Sclerotium Rolfsii ◽  
Wild Type ◽  
Gliocladium Virens ◽  
Rhizosphere Competence ◽  
Filter Paper Cellulase ◽  
Type Strains

Aqueous suspensions of conidia of Gliocladium virens strains Gl-3 and Gl-21 were exposed to both ultraviolet radiation and ethyl methanesulfonate. Two mutants of Gl-3 and three of Gl-21 were selected for tolerance to benomyl at 10 μg∙mL−1, as indicated by growth and conidial germination on benomyl-amended potato dextrose agar. The mutants differed considerably from their respective wild-type strains in appearance, growth habit, sporulation, carbon-source utilization, and enzyme activity profiles. Of 10 carbon sources tested, cellobiose, xylose, and xylan were the best for growth, galactose and glucose were intermediate, and arabinose, ribose, and rhamnose were poor sources of carbon. The wild-type strains and the mutants did not utilize cellulose as the sole carbon source for growth. Two benomyl-tolerant mutants of Gl-3 produced less cellulase (β-1,4-glucosidase, carboxymethylcellulase, filter-paper cellulase) than Gl-3. In contrast, mutants of Gl-21 produced more cellulase than the wild-type strain. Only Gl-3 provided control of blight on snapbean caused by Sclerotium rolfsii. Wild-type strain Gl-21 and all mutants from both strains were ineffective biocontrol agents. Key words: Gliocladium, benomyl tolerance, Sclerotium, rhizosphere competence.

scholarly journals Comparison of clinical acinetobacter strains using a carbon source growth assay

1990 ◽  
Vol 104 (3) ◽  
pp. 443-453 ◽  
Author(s):  
L. Dijkshoorn ◽  
A. Van Ooyen ◽  
W. C. J. Hop ◽  
M. Theuns ◽  
M. F. Michel
Keyword(s):  
Cluster Analysis ◽  
Carbon Source ◽  
Univariate Analysis ◽  
Carbon Sources ◽  
Protein Profiles ◽  
Growth Data ◽  
Epidemiological Factors ◽  
Growth Assay ◽  
Growth Profiles ◽  
Related Pattern

SUMMARYA quantitative carbon source growth assay, comprising ten carbon sources, was used to compare acinetobacter strains from three hospitals. The strains had been obtained during episodes of increased prevalence of isolations and were, for each hospital, assumed to be epidemiologically related. This assumption was supported by the electrophoretic protein profiles of the strains. Univariate analysis of growth data showed significant differences between strains from the three hospitals. Moreover, cluster analysis revealed that the major pattern in the data was related to the epidemiological origin of the strains. Exceptions to the epidemic-related pattern were observed. Thus, apart from epidemiological factors, other factors might contribute to carbon source growth profiles of the strains. It is concluded that the carbon growth assay may be useful to distinguish roughly between acinetobacter strains from different sites of origin. Further studies are required to analyse additional factors which influence carbon source growth of strains.

Regulation of yeast COX6 by the general transcription factor ABF1 and separate HAP2- and heme-responsive elements

1992 ◽  
Vol 12 (5) ◽  
pp. 2302-2314
Author(s):  
J D Trawick ◽  
N Kraut ◽  
F R Simon ◽  
R O Poyton
Keyword(s):  
Transcription Factor ◽  
Carbon Source ◽  
Protein Binding ◽  
Glucose Repression ◽  
Protein Complexes ◽  
Carbon Sources ◽  
Major Protein ◽  
Mobility Shift ◽  
Gel Mobility Shift ◽  
In Cells

Transcription of the Saccharomyces cerevisiae COX6 gene is regulated by heme and carbon source. It is also affected by the HAP2/3/4 transcription factor complex and by SNF1 and SSN6. Previously, we have shown that most of this regulation is mediated through UAS6, an 84-bp upstream activation segment of the COX6 promoter. In this study, by using linker scanning mutagenesis and protein binding assays, we have identified three elements within UAS6 and one element downstream of it that are important. Two of these, HDS1 (heme-dependent site 1; between -269 and -251 bp) and HDS2 (between -228 and -220 bp), mediate regulation of COX6 by heme. Both act negatively. The other two elements, domain 2 (between -279 and -269 bp) and domain 1 (between -302 and -281 bp), act positively. Domain 2 is required for optimal transcription in cells grown in repressing but not derepressing carbon sources. Domain 1 is essential for transcription per se in cells grown on repressing carbon sources, is required for optimal transcription in cells grown on a derepressing carbon source, is sufficient for glucose repression-derepression, and is the element of UAS6 at which HAP2 affects COX6 transcription. This element contains the major protein binding sites within UAS6. It has consensus binding sequences for ABF1 and HAP2. Gel mobility shift experiments show that domain 1 binds ABF1 and forms different numbers of DNA-protein complexes in extracts from cells grown in repressing or derepressing carbon sources. In contrast, gel mobility shift experiments have failed to reveal that HAP2 or HAP3 binds to domain 1 or that hap3 mutations affect the complexes bound to it. Together, these findings permit the following conclusions: COX6 transcription is regulated both positively and negatively; heme and carbon source exert their effects through different sites; domain 1 is absolutely essential for transcription on repressing carbon sources; ABF1 is a major component in the regulation of COX6 transcription; and the HAP2/3/4 complex most likely affects COX6 transcription indirectly.

scholarly journals Production of Feruloyl Esterase from Aspergillus niger by Solid-State Fermentation on Different Carbon Sources

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Shiyi Ou ◽  
Jing Zhang ◽  
Yong Wang ◽  
Ning Zhang
Keyword(s):  
Carbon Source ◽  
Nitrogen Source ◽  
Wheat Bran ◽  
Cell Walls ◽  
Carbon Sources ◽  
Feruloyl Esterase ◽  
Plant Cell Walls ◽  
Optimal Conditions ◽  
Carbon And Nitrogen ◽  
Maize Bran

A mixture of wheat bran with maize bran as a carbon source and addition of (NH4)SO4 as nitrogen source was found to significantly increase production of feruloyl esterase (FAE) enzyme compared with wheat bran as a sole carbon and nitrogen source. The optimal conditions in conical flasks were carbon source (30 g) to water 1 : 1, maize bran to wheat bran 1 : 2, (NH4)SO4 1.2 g and MgSO4 70 mg. Under these conditions, FAE activity was 7.68 mU/g. The FAE activity on the mixed carbon sources showed, high activity against the plant cell walls contained in the cultures.

scholarly journals The Cyclic AMP Receptor Protein Regulates Quorum Sensing and Global Gene Expression in Yersinia pestis during Planktonic Growth and Growth in Biofilms

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Jeremy T. Ritzert ◽  
George Minasov ◽  
Ryan Embry ◽  
Matthew J. Schipma ◽  
Karla J. F. Satchell
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Carbon Source ◽  
Cyclic Amp ◽  
Yersinia Pestis ◽  
Carbon Sources ◽  
Transcriptional Regulator ◽  
Receptor Protein ◽  
Content Type ◽  
Bacterial Physiology

ABSTRACT Cyclic AMP (cAMP) receptor protein (Crp) is an important transcriptional regulator of Yersinia pestis. Expression of crp increases during pneumonic plague as the pathogen depletes glucose and forms large biofilms within lungs. To better understand control of Y. pestis Crp, we determined a 1.8-Å crystal structure of the protein-cAMP complex. We found that compared to Escherichia coli Crp, C helix amino acid substitutions in Y. pestis Crp did not impact the cAMP dependency of Crp to bind DNA promoters. To investigate Y. pestis Crp-regulated genes during plague pneumonia, we performed RNA sequencing on both wild-type and Δcrp mutant bacteria growing in planktonic and biofilm states in minimal media with glucose or glycerol. Y. pestis Crp was found to dramatically alter expression of hundreds of genes in a manner dependent upon carbon source and growth state. Gel shift assays confirmed direct regulation of the malT and ptsG promoters, and Crp was then linked to Y. pestis growth on maltose as a sole carbon source. Iron regulation genes ybtA and fyuA were found to be indirectly regulated by Crp. A new connection between carbon source and quorum sensing was revealed as Crp was found to regulate production of acyl-homoserine lactones (AHLs) through direct and indirect regulation of genes for AHL synthetases and receptors. AHLs were subsequently identified in the lungs of Y. pestis-infected mice when crp expression was highest in Y. pestis biofilms. Thus, in addition to the well-studied pla gene, other Crp-regulated genes likely have important functions during plague infection. IMPORTANCE Bacterial pathogens have evolved extensive signaling pathways to translate environmental signals into changes in gene expression. While Crp has long been appreciated for its role in regulating metabolism of carbon sources in many bacterial species, transcriptional profiling has revealed that this protein regulates many other aspects of bacterial physiology. The plague pathogen Y. pestis requires this global regulator to survive in blood, skin, and lungs. During disease progression, this organism adapts to changes within these niches. In addition to regulating genes for metabolism of nonglucose sugars, we found that Crp regulates genes for virulence, metal acquisition, and quorum sensing by direct or indirect mechanisms. Thus, this single transcriptional regulator, which responds to changes in available carbon sources, can regulate multiple critical behaviors for causing disease.

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