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 Effect of Nitrate and Acetylene on nirS, cnorB, and nosZ Expression and Denitrification Activity in Pseudomonas mandelii

2009 ◽  
Vol 75 (15) ◽  
pp. 5082-5087 ◽  
Author(s):  
Saleema Saleh-Lakha ◽  
Kelly E. Shannon ◽  
Sherri L. Henderson ◽  
Bernie J. Zebarth ◽  
David L. Burton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gas Chromatography ◽  
Electron Acceptor ◽  
Pseudomonas Mandelii ◽  
Denitrification Gene ◽  
Reverse Transcription Quantitative Pcr ◽  
Denitrification Activity ◽  
Acetylene Blockage ◽  
Denitrification Genes ◽  
Denitrification Process

ABSTRACT Nitrate acts as an electron acceptor in the denitrification process. The effect of nitrate in the range of 0 to 1,000 mg/liter on Pseudomonas mandelii nirS, cnorB, and nosZ gene expression was studied, using quantitative reverse transcription-quantitative PCR. Denitrification activity was measured by using the acetylene blockage method and gas chromatography. The effect of acetylene on gene expression was assessed by comparing denitrification gene expression in P. mandelii culture grown in the presence or absence of acetylene. The higher the amount of NO3 − present, the greater the induction and the longer the denitrification genes remained expressed. nirS gene expression reached a maximum at 2, 4, 4, and 6 h in cultures grown in the presence of 0, 10, 100, and 1,000 mg of KNO3/liter, respectively, while induction of nirS gene ranged from 12- to 225-fold compared to time zero. cnorB gene expression also followed a similar trend. nosZ gene expression did not respond to NO3 − treatment under the conditions tested. Acetylene decreased nosZ gene expression but did not affect nirS or cnorB gene expression. These results showed that nirS and cnorB responded to nitrate concentrations; however, significant denitrification activity was only observed in culture with 1,000 mg of KNO3/liter, indicating that there was no relationship between gene expression and denitrification activity under the conditions tested.

scholarly journals Adaptation of Lactobacillus plantarum IMDO 130201, a Wheat Sourdough Isolate, to Growth in Wheat Sourdough Simulation Medium at Different pH Values through Differential Gene Expression

2011 ◽  
Vol 77 (10) ◽  
pp. 3406-3412 ◽  
Author(s):  
Gino Vrancken ◽  
Luc De Vuyst ◽  
Tom Rimaux ◽  
Joke Allemeersch ◽  
Stefan Weckx
Keyword(s):  
Gene Expression ◽  
Lactobacillus Plantarum ◽  
Differential Gene Expression ◽  
Lipoteichoic Acid ◽  
Low Ph ◽  
Exponential Growth Phase ◽  
Cellular Mechanisms ◽  
Content Type ◽  
Ph Values ◽  
Differential Gene

ABSTRACTSourdough is a very competitive and challenging environment for microorganisms. Usually, a stable microbiota composed of lactic acid bacteria (LAB) and yeasts dominates this ecosystem. Although sourdough is rich in carbohydrates, thus providing an ideal environment for microorganisms to grow, its low pH presents a particular challenge. The nature of the adaptation to this low pH was investigated forLactobacillus plantarumIMDO 130201, an isolate from a laboratory wheat sourdough fermentation. Batch fermentations were carried out in wheat sourdough simulation medium, and total RNA was isolated from mid-exponential-growth-phase cultures, followed by differential gene expression analysis using a LAB functional gene microarray. At low pH values, an increased expression of genes involved in peptide and amino acid metabolism was found as well as that of genes involved in plantaricin production and lipoteichoic acid biosynthesis. The results highlight cellular mechanisms that allowL. plantarumto function at a low environmental pH.

Effect of pH on Glycolate and Ammonia Excretion in L-MSO Treated Chlorella Cells

1987 ◽  
Vol 42 (5) ◽  
pp. 525-529
Author(s):  
Yoshihiro Shiraiwa ◽  
Georg H. Schmid
Keyword(s):  
Chlorella Vulgaris ◽  
Major Part ◽  
Ammonia Excretion ◽  
Low Ph ◽  
Final Concentration ◽  
The Other ◽  
Effect Of Ph ◽  
Photosynthetic Rates ◽  
Ph Values ◽  
Glycolate Metabolism

Abstract The effect of pH changes on the excretion of ammonia and glycolate from algal cells into the medium was investigated in L-MSO (final concentration, 0.5 mм) -treated High-and Low CO2-cells of Chlorella vulgaris 211-11 h. The excretion was analyzed in the condition in which the cells were continuously gassed with air at 25 °C. At the values tested, generally more ammonia was excreted in L-MSO-treated Low CO2-cells than in L-MSO treated High CO2-cells. In both kinds of algal cells more ammonia was excreted at low pH-values and absolutely no ammonia was excreted at pH 8. In the dark, no or only slight ammonia excretion was observed in both L-MSO-treated High and Low CO2-cells. Under all these conditions no or only very low glycolate excretion was observed in both L-MSO treated High and Low CO2-cells. In High CO2-cells rates of photosynthesis were high at pH 6 and lower at higher pH values. On the other hand Low CO2-cells showed practically little dependence of photosynthetic rates on the pH. This result might indicate that the major part of the ammonia excretion observed, was not due to the inhibition of photosynthesis at acid pH values. It is known that ammonia excretion in L-MSO treated algal cells is due to the inhibition of the refixation of ammonia which originates from the glycine-serine aminotransferase reaction in the glycolate pathway. Our results demonstrate that glycolate production and glycolate metabolism are more intense at low pH values when compared to high pH values. This is valid for both High and Low CO2-cells. Low CO2-cells in Chlorella vulgaris 211-11 h exhibit a more active glycolate metabolism than High CO2-cells.

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.

scholarly journals Nitric Oxide Reductase Gene Expression and Nitrous Oxide Production in Nitrate-Grown Pseudomonas mandelii

2008 ◽  
Vol 74 (22) ◽  
pp. 6876-6879 ◽  
Author(s):  
Saleema Saleh-Lakha ◽  
Kelly E. Shannon ◽  
Claudia Goyer ◽  
Jack T. Trevors ◽  
Bernie J. Zebarth ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Nitrous Oxide Emissions ◽  
Nitric Oxide Reductase ◽  
Reverse Transcription Pcr ◽  
Pseudomonas Mandelii ◽  
Reductase Gene ◽  
Nitrous Oxide Production ◽  
Pure Cultures

ABSTRACT Pure cultures of Pseudomonas mandelii were incubated with or without nitrate, which acts as a substrate and an electron acceptor for denitrification. Nitric oxide reductase (cnorB) gene expression was measured using a quantitative reverse transcription-PCR, and nitrous oxide emissions were measured by gas chromatography. P. mandelii cells in either the presence or absence of nitrate demonstrated an increase in cnorB gene expression during the first 3 h of growth. The level of expression of cnorB in nitrate-amended cells remained high (average, 2.06 × 108 transcripts/μg of RNA), while in untreated cells it decreased to an average of 3.63 × 106 transcripts/μg of RNA from 4 to 6 h. Nitrous oxide accumulation in the headspace was detected at 2 h, and cumulative emissions continued to increase over a 24-h period to 101 μmol in nitrate-amended cells. P. mandelii cnorB gene expression was not detected under aerobic conditions. These results demonstrate that P. mandelii cnorB gene expression was induced 203-fold at 4 h when nitrate was present in the medium. Accumulations of N2O indicated that the cNorB enzyme was synthesized and active.

Overexpression of atpI Encoding ATP Synthase Enhances the Electricity Production in Microbial Fuel Cells

2013 ◽  
Vol 860-863 ◽  
pp. 456-460
Author(s):  
Yu Pei Chen ◽  
Yu Chi Chang ◽  
Chao Lin Liu ◽  
Biing Cheng Lim ◽  
Jong Tar Kuo
Keyword(s):  
Gene Expression ◽  
Fuel Cells ◽  
Energy Metabolism ◽  
Atp Synthase ◽  
Applied Voltage ◽  
Microbial Fuel Cells ◽  
Fold Increase ◽  
Electricity Production ◽  
E Coli ◽  
Reverse Transcription Pcr

Microbial fuel cells (MFCs) have been paid much attention due to its clean and renewable energy. In recent years, MFCs performed without addition of mediator were reported. In this research, the gene expression of atpI involved in ATP synthase of energy metabolism was compared at 3.7 and 37 mV applied voltage by reverse-transcription PCR. At high applied voltage, gene expression of atpI caused a 11.6-fold increase more than that at low applied voltage. Accordingly, overexpression vector harboring atpI gene was further constructed to demonstrate the effect of ATP synthase on the electricity production in MFC. The result showed that the current generated by E. coli harboring atpI gene can efficiently and rapidly be enhanced. The current production with atpI gene overexpression in E. coli was 3-fold higher than that of only pET15b vector at 106th h. Consequently, these results verified that electricity production can be improved via introduction of energy metabolism gene without addition of mediator. Keywords: Microbial fuel cells, atpI, gene expression,electricity

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 (>5-fold increase, **p<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.

scholarly journals Lateral rectus muscle differentiation potential in paralytic esotropia patients

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qing Xia ◽  
Xiangtian Ling ◽  
Zhonghao Wang ◽  
Tao Shen ◽  
Minghao Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Rectus Muscle ◽  
Lateral Rectus ◽  
Control Group ◽  
Differentiation Potential ◽  
Partial Restoration ◽  
Reverse Transcription Pcr ◽  
Lateral Rectus Muscle

Abstract Purpose and background Recently, we found that maximal medial rectus recession and lateral rectus resection in patients with complete lateral rectus paralysis resulted in a partial restoration of abduction. In an attempt to understand some of the mechanisms involved with this effect we examined gene expression profiles of lateral recti from these patients, with our focus being directed to genes related to myogenesis. Materials and methods Lateral recti resected from patients with complete lateral rectus paralysis and those from concomitant esotropia (controls) were collected. Differences in gene expression profiles between these two groups were examined using microarray analysis and quantitative Reverse-transcription PCR (qRT-PCR). Results A total of 3056 differentially expressed genes (DEGs) were identified between these two groups. Within the paralytic esotropia group, 2081 genes were up-regulated and 975 down-regulated. The results of RT-PCR revealed that PAX7, MYOG, PITX1, SIX1 and SIX4 showed higher levels of expression, while that of MYOD a lower level of expression within the paralytic esotropia group as compared with that in the control group (p < 0.05). Conclusion The decreased expression of MYOD in the paralytic esotropia group suggested that extraocular muscle satellite cell (EOMSCs) differentiation processes were inhibited. Whereas the high expression levels of PAX7, SIX1/4 and MYOG, suggested that the EOMSCs were showing an effective potential for differentiation. The stimulation resulting from muscle surgery may induce EOMSCs to differentiate and thus restore abduction function.

scholarly journals Selection of reference genes for gene expression analysis in Liriodendron hybrids’ somatic embryogenesis and germinative tissues

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tingting Li ◽  
Weigao Yuan ◽  
Shuai Qiu ◽  
Jisen Shi
Keyword(s):  
Gene Expression ◽  
Somatic Embryogenesis ◽  
Reference Genes ◽  
Gene Selection ◽  
Elongation Factor ◽  
Reverse Transcription Pcr ◽  
Expression Of Genes ◽  
Suitable Reference ◽  
Functional Analyses ◽  
Elongation Factor 1

AbstractThe differential expression of genes is crucial for plant somatic embryogenesis (SE), and the accurate quantification of gene expression levels relies on choosing appropriate reference genes. To select the most suitable reference genes for SE studies, 10 commonly used reference genes were examined in synchronized somatic embryogenic and subsequent germinative cultures of Liriodendron hybrids by using quantitative real-time reverse transcription PCR. Four popular normalization algorithms: geNorm, NormFinder, Bestkeeper and Delta-Ct were used to select and validate the suitable reference genes. The results showed that elongation factor 1-gamma, histone H1 linker protein, glyceraldehyde-3-phosphate dehydrogenase and α-tubulin were suitable for SE tissues, while elongation factor 1-gamma and actin were best for the germinative organ tissues. Our work will benefit future studies of gene expression and functional analyses of SE in Liriodendron hybrids. It is also serves as a guide of reference gene selection in early embryonic gene expression analyses for other woody plant species.

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.

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