Effects of xanthotoxin treatment on trichothecene production inFusarium sporotrichioides

2008 ◽  
Vol 54 (12) ◽  
pp. 1023-1031 ◽  
Author(s):  
Nancy J. Alexander ◽  
Susan P. McCormick ◽  
Judith A. Blackburn
Keyword(s):  
Gene Expression ◽  
Reverse Transcriptase ◽  
Plant Defense ◽  
Biosynthetic Pathway ◽  
Fold Increase ◽  
Toxin Production ◽  
Fusarium Sporotrichioides ◽  
Defense Compounds ◽  
Liquid Cultures ◽  
Oxygenase Activity

There are 4 P450 oxygenases involved in the biosynthesis of T-2 toxin in Fusarium sporotrichioides . Exactly how these enzymes react to antimicrobial plant defense compounds is unknown. Xanthotoxin (8-methoxypsoralen) is a phototoxic furanocoumarin that acts as a P450 oxygenase inhibitor. The current study shows that the addition of concentrations of 1.0 mmol/L or less of xanthotoxin to liquid cultures of F. sporotrichioides NRRL3299 can effectively block T-2 toxin production and cause an increase in accumulation of trichodiene, the hydrocarbon precursor of trichothecenes. The addition of xanthotoxin to liquid cultures of a trichodiene-accumulating F. sporotrichioides Tri4–mutant caused a 3- to 10-fold increase in trichodiene accumulation, suggesting that xanthotoxin not only blocks trichothecene oxygenation reactions, but may in some way also promote the synthesis of trichodiene. Feeding studies showed that 2 of the 4 P450 oxygenases, TRI4 and TRI1, were more sensitive to xanthotoxin, while oxygenases TRI11 and TRI13 were unaffected. Quantitative reverse-transcriptase PCR indicated that several of the genes in the toxin biosynthetic pathway were upregulated by xanthotoxin, with Tri4 showing the highest increase in expression. These results indicate that while xanthotoxin inhibits specific P450 oxygenase activity, it also has an effect on gene expression.

Hyperglycemia modulates angiotensinogen gene expression

2001 ◽  
Vol 281 (3) ◽  
pp. R795-R802 ◽  
Author(s):  
Ilan Gabriely ◽  
Xiao Man Yang ◽  
Jane A. Cases ◽  
Xiao Hui Ma ◽  
Luciano Rossetti ◽  
...  
Keyword(s):  
Gene Expression ◽  
Insulin Resistance ◽  
Biosynthetic Pathway ◽  
Fold Increase ◽  
Suppressive Effect ◽  
Sprague Dawley ◽  
Hexosamine Biosynthetic Pathway ◽  
Obese Rats ◽  
Agt Gene

Elevated plasma angiotensinogen (AGT) levels have been demonstrated in insulin-resistant states such as obesity and type 2 diabetes mellitus (DM2), conditions that are directly correlated to hypertension. We examined whether hyperinsulinemia or hyperglycemia may modulate fat and liver AGT gene expression and whether obesity and insulin resistance are associated with abnormal AGT regulation. In addition, because the hexosamine biosynthetic pathway is considered to function as a biochemical sensor of intracellular nutrient availability, we hypothesized that activation of this pathway would acutely mediate in vivo the induction of AGT gene expression in fat and liver. We studied chronically catheterized lean (∼300 g) and obese (∼450 g) Sprague-Dawley rats in four clamp studies ( n= 3/group), creating physiological hyperinsulinemia (∼60 μU/ml, by an insulin clamp), hyperglycemia (∼18 mM, by a pancreatic clamp using somatostatin to prevent endogenous insulin secretion), or euglycemia with glucosamine infusion (GlcN; 30 μmol · kg−1 · min−1) and equivalent saline infusions (as a control). Although insulin infusion suppressed AGT gene expression in fat and liver of lean rats, the obese rats demonstrated resistance to this effect of insulin. In contrast, hyperglycemia at basal insulin levels activated AGT gene expression in fat and liver by approximately threefold in both lean and obese rats ( P < 0.001). Finally, GlcN infusion simulated the effects of hyperglycemia on fat and liver AGT gene expression (2-fold increase, P < 0.001). Our results support the hypothesis that physiological nutrient “pulses” may acutely induce AGT gene expression in both adipose tissue and liver through the activation of the hexosamine biosynthetic pathway. Resistance to the suppressive effect of insulin on AGT expression in obese rats may potentiate the effect of nutrients on AGT gene expression. We propose that increased AGT gene expression and possibly its production may provide another link between obesity/insulin resistance and hypertension.

scholarly journals Effect of pH and Temperature on Denitrification Gene Expression and Activity in Pseudomonas mandelii

2009 ◽  
Vol 75 (12) ◽  
pp. 3903-3911 ◽  
Author(s):  
Saleema Saleh-Lakha ◽  
Kelly E. Shannon ◽  
Sherri L. Henderson ◽  
Claudia Goyer ◽  
Jack T. Trevors ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fold Increase ◽  
Low Ph ◽  
Effect Of Ph ◽  
Liquid Cultures ◽  
Ph Values ◽  
Reverse Transcription Pcr ◽  
Pseudomonas Mandelii ◽  
Denitrification Gene ◽  
Denitrification Activity

ABSTRACT Pseudomonas mandelii liquid cultures were studied to determine the effect of pH and temperature on denitrification gene expression, which was quantified by quantitative reverse transcription-PCR. Denitrification was measured by the accumulation of nitrous oxide (N2O) in the headspace in the presence of acetylene. Levels of gene expression of nirS and cnorB at pH 5 were 539-fold and 6,190-fold lower, respectively, than the levels of gene expression for cells grown at pH 6, 7, and 8 between 4 h and 8 h. Cumulative denitrification levels were 28 μmol, 63 μmol, and 22 μmol at pH 6, 7, and 8, respectively, at 8 h, whereas negligible denitrification was measured at pH 5. P. mandelii cells grown at 20°C and 30°C exhibited 9-fold and 94-fold increases in levels of cnorB expression between 0 h and 2 h, respectively, and an average 17-fold increase in levels of nirS gene expression. In contrast, induction of cnorB and nirS gene expression for P. mandelii cells grown at 10°C did not occur in the first 4 h. Levels of cumulative denitrification at 10 h were 6.6 μmol for P. mandelii cells grown at 10°C and 20°C and 30 μmol for cells grown at 30°C. Overall, levels of cnorB and nirS expression were relatively insensitive to pH values over the range of pH 6 to 8 but were substantially reduced at pH 5, whereas gene expression was sensitive to temperature, with induction and time to achieve maximum gene expression delayed as the temperature decreased from 30°C. Low pH and temperature negatively affected denitrification activity.

scholarly journals Production of benzylglucosinolate by engineering and optimizing the biosynthetic pathway in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Cuiwei Wang ◽  
Christoph Crocoll ◽  
Christina Spuur Nødvig ◽  
Uffe Hasbro Mortensen ◽  
Sidsel Ettrup Clemmensen ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Arabidopsis Thaliana ◽  
Amino Acid ◽  
Biosynthetic Pathway ◽  
Fold Increase ◽  
Defense Compounds ◽  
Aps Kinase ◽  
Genome Integration ◽  
Enhanced Expression ◽  
Health Promoting

AbstractGlucosinolates are amino acid-derived defense compounds characteristic of the Brassicales order. Benzylglucosinolate (BGLS) derived from phenylalanine is associated with health-promoting effects, which has primed a desire to produce BGLS in microorganisms for a stable and rich source. In this study, we engineered the BGLS production in Saccharomyces cerevisiae by either stably integrating the biosynthetic genes into the genome or introducing them from plasmids. A comparison of the two approaches exhibited a significantly higher level of BGLS production (9.3-fold) by expression of the genes from genome than from plasmids. Towards optimization of BGLS production from genes stably integrated into the genome, we enhanced expression of the entry point enzymes CYP79A2 and CYP83B1 resulting in a 2-fold increase in BGLS production, but also a 4.8-fold increase in the biosynthesis of the last intermediate desulfo-benzylglucosinolate (dsBGLS). To alleviate the metabolic bottleneck in the last step converting dsBGLS to BGLS by 3’-phosphoadenosine-5’-phosphosulfate (PAPS)-dependent sulfotransferase, SOT16, we first obtained an increased BGLS production by 1.7-fold when overexpressing SOT16. Next, we introduced APS kinase APK1 of Arabidopsis thaliana for efficient PAPS regeneration, which improved the level of BGLS production by 1.7-fold. Our work shows an optimized production of BGLS in S. cerevisiae and the effect of different approaches for engineering the biosynthetic pathway (plasmid expression and genome integration) on the production level of BGLS.

scholarly journals A systems approach to model the relationship between aflatoxin gene cluster expression, environmental factors, growth and toxin production by Aspergillus flavus

2011 ◽  
Vol 9 (69) ◽  
pp. 757-767 ◽  
Author(s):  
Ahmed Abdel-Hadi ◽  
Markus Schmidt-Heydt ◽  
Roberto Parra ◽  
Rolf Geisen ◽  
Naresh Magan
Keyword(s):  
Gene Expression ◽  
Environmental Factors ◽  
Aspergillus Flavus ◽  
Biosynthetic Pathway ◽  
Systems Approach ◽  
Toxin Production ◽  
Relative Expression ◽  
Temperature Conditions ◽  
The Impact ◽  
The Relationship

A microarray analysis was used to examine the effect of combinations of water activity ( a w , 0.995–0.90) and temperature (20–42°C) on the activation of aflatoxin biosynthetic genes (30 genes) in Aspergillus flavus grown on a conducive YES (20 g yeast extract, 150 g sucrose, 1 g MgSO 4 ·7H 2 O) medium. The relative expression of 10 key genes ( aflF , aflD , aflE , aflM , aflO , aflP , aflQ , aflX , aflR and aflS ) in the biosynthetic pathway was examined in relation to different environmental factors and phenotypic aflatoxin B 1 (AFB 1 ) production. These data, plus data on relative growth rates and AFB 1 production under different a w × temperature conditions were used to develop a mixed-growth-associated product formation model. The gene expression data were normalized and then used as a linear combination of the data for all 10 genes and combined with the physical model. This was used to relate gene expression to a w and temperature conditions to predict AFB 1 production. The relationship between the observed AFB 1 production provided a good linear regression fit to the predicted production based in the model. The model was then validated by examining datasets outside the model fitting conditions used (37°C, 40°C and different a w levels). The relationship between structural genes ( aflD , aflM ) in the biosynthetic pathway and the regulatory genes ( aflS , aflJ ) was examined in relation to a w and temperature by developing ternary diagrams of relative expression. These findings are important in developing a more integrated systems approach by combining gene expression, ecophysiological influences and growth data to predict mycotoxin production. This could help in developing a more targeted approach to develop prevention strategies to control such carcinogenic natural metabolites that are prevalent in many staple food products. The model could also be used to predict the impact of climate change on toxin production.

scholarly journals Engineering and optimization of the 2-phenylethylglucosinolate production in Nicotiana benthamiana by combining biosynthetic genes from Barbarea vulgaris and Arabidopsis thaliana

2020 ◽  
Author(s):  
Cuiwei Wang ◽  
Christoph Crocoll ◽  
Niels Agerbirk ◽  
Barbara Ann Halkier
Keyword(s):  
Arabidopsis Thaliana ◽  
Nicotiana Benthamiana ◽  
Biosynthetic Pathway ◽  
Fold Increase ◽  
Chain Elongation ◽  
Heterologous Host ◽  
Barbarea Vulgaris ◽  
Donor Plant ◽  
Defense Compounds ◽  
Novel Approach

AbstractAmong the glucosinolate (GLS) defense compounds characteristic of the Brassicales order, several have been shown to promote human health. This includes 2-phenylethylglucosinolate (2PE) derived from homophenylalanine (HPhe). In this study, we used transient expression in Nicotiana benthamiana to validate and characterize previously predicted key genes in the 2PE biosynthetic pathway from Barbarea vulgaris and demonstrate the feasibility of engineering 2PE production. We used genes from B. vulgaris and Arabidopsis thaliana, in which the biosynthesis of GLSs is predominantly derived from HPhe and dihomomethionine, respectively. The resulting GLS profiles partially mirrored GLS profiles in the gene donor plant, but in both cases the profiles in N. benthamiana were wider than in the native plants. We found that BvBCAT4 is a more efficient entry enzyme for biosynthesis of both HPhe and dihomomethionine and that MAM1 enzymes determine the chain-elongated profile. Co-expression of the chain elongation pathway and CYP79F6 from B. vulgaris with the remaining aliphatic GLS core pathway genes from A. thaliana, demonstrated the feasibility of engineering production of 2PE in N. benthamiana. Noticeably, the HPhe-converting enzyme BvCYP79F6 in the core GLS pathway belongs to the CYP79F subfamily, a family believed to have substrate specificity towards chain-elongated methionine derivatives. Replacing the B. vulgaris chain elongation pathway with a chimeric pathway consisting of BvBCAT4, BvMAM1, AtIPMI and AtIPMDH1 resulted in an additional 2-fold increase in 2PE production, demonstrating that chimeric pathway with genes from different species can increase flux and boost production in an engineered pathway. Our study provides a novel approach to produce the important HPhe and 2PE in a heterologous host. Chimeric engineering of a complex biosynthetic pathway enabled detailed understanding of catalytic properties of individual enzymes - a prerequisite for understanding biochemical evolution - and with biotechnological and plant breeding potentials of new-to-nature gene combinations.

Evidence of Browning of White Adipocytes in Poorly Survived Fat Grafts in Patients

2021 ◽  
Author(s):  
Tong Liu ◽  
Su Fu ◽  
Qian Wang ◽  
Hao Cheng ◽  
Dali Mu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Uncoupling Protein ◽  
Fold Increase ◽  
Fat Grafting ◽  
Electronic Microscopy ◽  
Uncoupling Protein 1 ◽  
Fat Transfer ◽  
Flap Transfer ◽  
Fat Grafts ◽  
White Adipocytes

Abstract Background Browning adipocytes induced by burn and cancer were assumed less viable and more prone to necrosis for their hypermetabolic properties. Recent studies have shown browning of white adipose after fat engraftment in mice. Objectives We tend to evaluate whether fat transfer could induce browning biogenesis in fat grafts in humans and if it is associated with graft necrosis. Methods Necrotic adipose grafts were excised from 11 patients diagnosed with fat necrosis after fat grafting or flap transfer. Non-necrotic fat grafts were from 5 patients undergoing revisionary surgeries after flap transfer. Histology and electronic microscopy, protein and gene expression of browning related marker analyses were performed. Results Fat grafts with necrosis demonstrated a higher gene expression level of uncoupling protein-1 (&gt;5-fold increase, **p&lt;0.01), a master beige adipocyte marker, than non-necrotic fat grafts. Electronic microscopy and histology showed that browning adipocytes were presented in necrotic adipose in patients. Conclusions Fat transfer induced browning adipocytes in patients and was evident in patients with post grafting necrosis.

Root exposure to apple replant disease soil triggers local defense response and rhizoplane microbiome dysbiosis

2021 ◽  
Author(s):  
Alicia Balbín-Suárez ◽  
Samuel Jacquiod ◽  
Annmarie-Deetja Rohr ◽  
Benye Liu ◽  
Henryk Flachowsky ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plant Defense ◽  
Defense Response ◽  
Soil Column ◽  
Soil Layer ◽  
Soil Microbiome ◽  
Control Soil ◽  
Apple Rootstocks ◽  
Apple Replant Disease ◽  
Replant Disease

Abstract A soil column split-root experiment was designed to investigate the ability of apple replant disease (ARD) causing agents to spread in soil. ‘M26’ apple rootstocks grew into a top layer of Control soil, followed by a barrier-free split-soil layer (Control soil/ARD soil). We observed a severely reduced root growth, concomitant with enhanced gene expression of phytoalexin biosynthetic genes and phytoalexin content in roots from ARD soil, indicating a pronounced local plant defense response. Amplicon sequencing (bacteria, archaea, fungi) revealed local shifts in diversity and composition of microorganisms in the rhizoplane of roots from ARD soil. An enrichment of OTUs affiliated to potential ARD fungal pathogens (Ilyonectria and Nectria sp.) and bacteria frequently associated with ARD (Streptomyces, Variovorax) was noted. In conclusion, our integrated study supports the idea of ARD being local and not spreading into surrounding soil, as only the roots in ARD soil were affected in terms of growth, phytoalexin biosynthetic gene expression, phytoalexin production, and altered microbiome structure. This study further reinforces the microbiological nature of ARD, being likely triggered by a disturbed soil microbiome enriched with low mobility ARD-causing agents that induce a strong plant defense and rhizoplane microbiome dysbiosis, concurring with root damage.

Growth, nisA Gene Expression, and In Situ Activity of Novel Lactococcus lactis subsp. cremoris Costarter Culture in Commercial Hard Cheese Production

2017 ◽  
Vol 80 (12) ◽  
pp. 2137-2146 ◽  
Author(s):  
Dimitrios Noutsopoulos ◽  
Athanasia Kakouri ◽  
Eleftheria Kartezini ◽  
Dimitrios Pappas ◽  
Efstathios Hatziloukas ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lactococcus Lactis ◽  
Starter Culture ◽  
Fold Increase ◽  
Raw Milk ◽  
Good Growth ◽  
Lactococcus Lactis Subsp ◽  
Quantitative Expression ◽  
Hard Cheese

ABSTRACT This study evaluated in situ expression of the nisA gene by an indigenous, nisin A–producing (NisA+) Lactococcus lactis subsp. cremoris raw milk genotype, represented by strain M78, in traditional Greek Graviera cheeses under real factory-scale manufacturing and ripening conditions. Cheeses were produced with added a mixed thermophilic and mesophilic commercial starter culture (CSC) or with the CSC plus strain M78 (CSC+M78). Cheeses were sampled after curd cooking (day 0), fermentation of the unsalted molds for 24 h (day 1), brining (day 7), and ripening of the brined molds (14 to 15 kg each) for 30 days in a fully controlled industrial room (16.5°C; 91% relative humidity; day 37). Total RNA was directly extracted from the cheese samples, and the expression of nisA gene was evaluated by real-time reverse transcription PCR (qRT-PCR). Agar overlay and well diffusion bioassays were correspondingly used for in situ detection of the M78 NisA+ colonies in the cheese agar plates and antilisterial activity in whole-cheese slurry samples, respectively. Agar overlay assays showed good growth (&gt;8 log CFU/g of cheese) of the NisA+ strain M78 in coculture with the CSC and vice versa. The nisA expression was detected in CSC+M78 cheese samples only, with its expression levels being the highest (16-fold increase compared with those of the control gene) on day 1, followed by significant reduction on day 7 and almost negligible expression on day 37. Based on the results, certain intrinsic and mainly implicit hurdle factors appeared to reduce growth prevalence rates and decrease nisA gene expression, as well as the nisin A–mediated antilisterial activities of the NisA+ strain M78 postfermentation. To our knowledge, this is the first report on quantitative expression of the nisA gene in a Greek cooked hard cheese during commercial manufacturing and ripening conditions by using a novel, rarely isolated, indigenous NisA+ L. lactis subsp. cremoris genotype as costarter culture.

scholarly journals Transcription Factors as the “Blitzkrieg” of Plant Defense: A Pragmatic View of Nitric Oxide’s Role in Gene Regulation

2021 ◽  
Vol 22 (2) ◽  
pp. 522
Author(s):  
Noreen Falak ◽  
Qari Muhammad Imran ◽  
Adil Hussain ◽  
Byung-Wook Yun
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Plant Defense ◽  
Systemic Acquired Resistance ◽  
Defense Mechanism ◽  
Regulation Of Gene Expression ◽  
Acquired Resistance ◽  
Biological Processes ◽  
Genetic Components ◽  
Transcriptional Changes

Plants are in continuous conflict with the environmental constraints and their sessile nature demands a fine-tuned, well-designed defense mechanism that can cope with a multitude of biotic and abiotic assaults. Therefore, plants have developed innate immunity, R-gene-mediated resistance, and systemic acquired resistance to ensure their survival. Transcription factors (TFs) are among the most important genetic components for the regulation of gene expression and several other biological processes. They bind to specific sequences in the DNA called transcription factor binding sites (TFBSs) that are present in the regulatory regions of genes. Depending on the environmental conditions, TFs can either enhance or suppress transcriptional processes. In the last couple of decades, nitric oxide (NO) emerged as a crucial molecule for signaling and regulating biological processes. Here, we have overviewed the plant defense system, the role of TFs in mediating the defense response, and that how NO can manipulate transcriptional changes including direct post-translational modifications of TFs. We also propose that NO might regulate gene expression by regulating the recruitment of RNA polymerase during transcription.

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