scholarly journals Isocitrate dehydrogenase of Bacillus cereus is involved in biofilm formation

2021 ◽  
Author(s):  
Linlin Zhao ◽  
Qing Liu ◽  
Qiubin Huang ◽  
Fengying Liu ◽  
Huiping Liu ◽  
...  
Keyword(s):  
Citric Acid ◽  
Bacillus Cereus ◽  
Isocitrate Dehydrogenase ◽  
Biofilm Formation ◽  
Gene Knockout ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Stage I ◽  
Sporulation Process ◽  
Sporulation Rate

Abstract Tricarboxylic acid cycle (TCA cycle) is a central carbon metabolism pathway in prokaryotes and eukaryotes, and involved in matter metabolism and energy production. Isocitrate dehydrogenase (IDH), which is a key enzyme in the TCA cycle, participates in the formation of biofilms in Staphylococcus aureus by regulating the redox state inside the cell. At present, it remains to be clarified whether IDH is involved in the formation of Bacillus cereus biofilms. In this study, we found a gene icdH annotated as encoding IDH in the B. cereus genome, and cloned and expressed the protein encoded by this gene. The enzyme activity assay showed that the protein had IDH activity dependent on NADP+, indicating that this gene encoded an IDH. The mutant ΔicdH was obtained by gene knockout. Phenotypic analysis showed that the biofilm yield and sporulation rate of the mutant ΔicdH decreased. To reveal the role of IDH in biofilm formation, extracellular pH and citric acid content were measured. The results showed that a B.cereus 0–9 strain that lacked IDH exhibited accumulation of citric acid and acidification of the extracellular matrix. Given that citric acid is a metal chelator, the accumulation of citric acid may lead to a lack of metal ions in cells, resulting in reduced cell viability and affecting biofilm formation. Consistent with this hypothesis, the addition of excess Fe3+ restored biofilm formation in the mutant. These results suggest that IDH in B.cereus may regulate biofilm formation by modulating intracellular redox homeostasis. In addition, we found that the icdH deletion of B. cereus 0–9 resulted in the destruction of the stage I of sporulation process, and thus resulted in a reduced sporulation rate, which was significantly different from sporulation in B. subtilis caused by interruption of the stage I sporulation process due to icdH loss.

scholarly journals A Dysfunctional Tricarboxylic Acid Cycle Enhances Fitness of Staphylococcus epidermidis During β-Lactam Stress

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Vinai Chittezham Thomas ◽  
Lauren C. Kinkead ◽  
Ashley Janssen ◽  
Carolyn R. Schaeffer ◽  
Keith M. Woods ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Citric Acid ◽  
Cell Surface ◽  
Staphylococcus Epidermidis ◽  
Citric Acid Cycle ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Content Type ◽  
Acid Cycle

ABSTRACT A recent controversial hypothesis suggested that the bactericidal action of antibiotics is due to the generation of endogenous reactive oxygen species (ROS), a process requiring the citric acid cycle (tricarboxylic acid [TCA] cycle). To test this hypothesis, we assessed the ability of oxacillin to induce ROS production and cell death in Staphylococcus epidermidis strain 1457 and an isogenic citric acid cycle mutant. Our results confirm a contributory role for TCA-dependent ROS in enhancing susceptibility of S. epidermidis toward β-lactam antibiotics and also revealed a propensity for clinical isolates to accumulate TCA cycle dysfunctions presumably as a way to tolerate these antibiotics. The increased protection from β-lactam antibiotics could result from pleiotropic effects of a dysfunctional TCA cycle, including increased resistance to oxidative stress, reduced susceptibility to autolysis, and a more positively charged cell surface. IMPORTANCE Staphylococcus epidermidis, a normal inhabitant of the human skin microflora, is the most common cause of indwelling medical device infections. In the present study, we analyzed 126 clinical S. epidermidis isolates and discovered that tricarboxylic acid (TCA) cycle dysfunctions are relatively common in the clinical environment. We determined that a dysfunctional TCA cycle enables S. epidermidis to resist oxidative stress and alter its cell surface properties, making it less susceptible to β-lactam antibiotics.

scholarly journals Involvement of enzymes of amino acid metabolism and tricarboxylic acid cycle in bovine oocyte maturation in vitro

Reproduction ◽  
2003 ◽  
pp. 753-763 ◽  
Author(s):  
P Cetica ◽  
L Pintos ◽  
G Dalvit ◽  
M Beconi
Keyword(s):  
Amino Acid ◽  
Isocitrate Dehydrogenase ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Cumulus Cells ◽  
Tricarboxylic Acid ◽  
Maturation In Vitro

Few studies demonstrate at a biochemical level the metabolic profile of both cumulus cells and the oocyte during maturation. The aim of the present study was to investigate the differential participation of enzymatic activity in cumulus cells and in the oocyte during in vitro maturation (IVM) by studying the activity of enzymes involved in the control of amino acid metabolism, alanine aminotransferase (ALT) and aspartate aminotransferase (AST); and the tricarboxylic acid (TCA) cycle, isocitrate dehydrogenase (IDH) and malate dehydrogenase (MDH). No NAD-dependent isocitrate dehydrogenase (NAD-IDH) activity was recorded in cumulus-oocyte complexes (COCs). ALT, AST, NADP-dependent isocitrate dehydrogenase (NADP-IDH) and MDH enzymatic units remained constant in cumulus cells and oocytes during IVM. Specific activities increased in oocytes and decreased in cumulus cells as a result of IVM (P<0.05). Similar activity of both transaminases was detected in cumulus cells, unlike in the oocyte, in which activity of AST was 4.4 times greater than that of ALT (P<0.05). High NADP-IDH and MDH activity was detected in the oocyte. Addition of alanine, aspartate, isocitrate + NADP, oxaloacetate or malate + NAD to maturation media increased the percentage of denuded oocytes reaching maturation (P<0.05), in contrast to COCs in which differences were not observed by addition of these substrates and co-enzymes. The activity of studied enzymes and the use of oxidative substrates denotes a major participation of transaminations and the TCA cycle in the process of gamete maturation. The oocyte thus seems versatile in the use of several oxidative substrates depending on the redox state.

scholarly journals SpoVG is an important regulator of sporulation and affects biofilm formation by regulating Spo0A transcription in Bacillus cereus 0–9

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qiubin Huang ◽  
Zhen Zhang ◽  
Qing Liu ◽  
Fengying Liu ◽  
Yupeng Liu ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Biofilm Formation ◽  
Target Gene ◽  
Plant Diseases ◽  
Transcriptional Fusion ◽  
Transcription Level ◽  
Gram Positive ◽  
Qrt Pcr ◽  
Sporulation Process ◽  
Important Regulator

Abstract Background Bacillus cereus 0–9, a Gram-positive, endospore-forming bacterium isolated from healthy wheat roots in our previous research, is considered to be an effective biocontrol strain against several soil-borne plant diseases. SpoVG, a regulator that is broadly conserved among many Gram-positive bacteria, may help this organism coordinate environmental growth and virulence to survive. This study aimed to explore the multiple functions of SpoVG in B. cereus 0–9. Methods The gene knockout strains were constructed by homologous recombination, and the sporulation process of B. cereus 0–9 and its mutants were observed by fluorescence staining method. We further determined the spore yields and biofilm formation abilities of test strains. Transcriptional fusion strains were constructed by overlapping PCR technique, and the promoter activity of the target gene was detected by measuring its fluorescence intensity. The biofilm production and colonial morphology of B. cereus 0–9 and its mutants were determined to study the functions of the target genes, and the transcription level of the target gene was determined by qRT-PCR. Results According to observation of the sporulation process of B. cereus 0–9 in germination medium, SpoVG is crucial for regulating sporulation stage V of B. cereus 0–9, which is identical to that of Bacillus subtilis but differs from that of Bacillus anthracis. In addition, SpoVG could influence biofilm formation of B. cereus 0–9. The transcription levels of two genes closely related to biofilm-formation, sipW and calY, were downregulated in a ΔspoVG mutant. The role of SpoVG in regulating biofilm formation was further explored by deleting the genes abrB and sinR in the ΔspoVG mutant, respectively, generating the double mutant strains ΔspoVGΔabrB and ΔspoVGΔsinR. The phenotypes of these double mutants were congruent with those of the single abrB and sinR deletion strains, respectively, which showed increased biofilm formation. This indicated that spoVG was located upstream of abrB and sinR in the regulatory pathway of B. cereus biofilm formation. Further, the results of qRT-PCR and the luminescence intensity of transcriptional fusion strains indicated that spoVG gene deletion could inhibit the transcription of Spo0A. Conclusions SpoVG, an important regulator in the sporulation of B. cereus, is located upstream of Spo0A and participates in regulation of biofilm formation of B. cereus 0–9 through regulating the transcription level of spo0A. Sporulation and biofilm formation are crucial mechanisms by which bacteria respond to adverse conditions. SpoVG is therefore an important regulator of Spo0A and is crucial for both sporulation and biofilm formation of B. cereus 0–9. This study provides a new insight into the regulatory mechanism of environmental adaptation in bacteria and a foundation for future studies on biofilm formation of B. cereus.

Tricarboxylic acid cycle enzymes of a pseudophyllid cestode Penetrocephalus ganapatii

1990 ◽  
Vol 64 (1) ◽  
pp. 51-53
Author(s):  
S. Dhandayuthapani ◽  
K. Nellaiappan
Keyword(s):  
Isocitrate Dehydrogenase ◽  
Citrate Synthase ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Reverse Direction ◽  
Acid Cycle ◽  
Tca Cycle Enzymes ◽  
The Tca Cycle ◽  
Atp Generation

ABSTRACTStudies on the tricarboxylic acid cycle (TCA cycle) enzymes of Penetrocephalus ganapatii reveal that the TCA cycle is only partially operative, as some of the enzymes at the start of the cycle viz. citrate synthase, aconitase and isocitrate dehydrogenase are found to be low in their activities. The high activities of malate dehydrogenase and fumarase, showing affinity towards a reverse direction, indicate that the TCA cycle operates in the reverse direction resulting in the formation of fumarate. The low succinate dehydrogenase/fumarate reductase ratio suggests that ATP generation may occur at site I of the respiratory chain during the reduction of fumarate into succinate.

scholarly journals Isocitrate dehydrogenase of Bacillus cereus is involved in biofilm formation

2021 ◽  
Vol 37 (12) ◽  
Author(s):  
Linlin Zhao ◽  
Qing Liu ◽  
Qiubin Huang ◽  
Fengying Liu ◽  
Huiping Liu ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Isocitrate Dehydrogenase ◽  
Biofilm Formation

scholarly journals Effect of Huangqin Tang on Urine Metabolic Profile in Rats with Ulcerative Colitis Based on UPLC-Q-Exactive Orbitrap MS

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Dunfang Wang ◽  
Xuran Ma ◽  
Shanshan Guo ◽  
Yanli Wang ◽  
Tao Li ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
Fatty Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Unsaturated Fatty Acids ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Q Exactive ◽  
Therapeutic Mechanisms

As a classic prescription, Huangqin Tang (HQT) has been widely applied to treat ulcerative colitis (UC), although its pharmacological mechanisms are not clear. In this study, urine metabolomics was first analysed to explore the therapeutic mechanisms of HQT in UC rats induced by TNBS. We identified 28 potential biomarkers affected by HQT that might cause changes in urine metabolism in UC rats, mapped the network of metabolic pathways, and revealed how HQT affects metabolism of UC rats. The results showed that UC affects amino acid metabolism and biosynthesis of unsaturated fatty acids and impairs the tricarboxylic acid cycle (TCA cycle). UC induced inflammatory and gastrointestinal reactions by inhibiting the transport of fatty acids and disrupting amino acid metabolism. HQT plays key roles via regulating the level of biomarkers in the metabolism of amino acids, lipids, and so on, normalizing metabolic disorders. In addition, histopathology and other bioinformatics analysis further confirm that HQT altered UC rat physiology and pathology, ultimately affecting metabolic function of UC rats.

scholarly journals An Untargeted Metabolomics Investigation of Milk from Dairy Cows with Clinical Mastitis by 1H-NMR

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1707
Author(s):  
Chenglin Zhu ◽  
Kaiwei Tang ◽  
Xuan Lu ◽  
Junni Tang ◽  
Luca Laghi
Keyword(s):  
Dairy Cows ◽  
1H Nmr ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Quantitative Information ◽  
Clinical Mastitis ◽  
Economic Losses ◽  
Resonance Spectroscopy ◽  
Mastitic Milk ◽  
Chemical Groups

Mastitis is one of the diseases with the highest incidence in dairy cows, causing huge economic losses to the dairy industry all over the world. The aim of the study was to characterize mastitic milk metabolome through untargeted nuclear magnetic resonance spectroscopy (1H-NMR). Taking advantage of the high reproducibility of 1H-NMR, we had the opportunity to provide quantitative information for all the metabolites identified. Fifty-four molecules were characterized, sorted mainly into the chemical groups, namely amino acids, peptides and analogues, carbohydrates and derivates, organic acids and derivates, nucleosides, nucleotides and analogues. Combined with serum metabolomic investigations, several pathways were addressed to explain the mechanisms of milk metabolome variation affected by clinical mastitis, such as tricarboxylic acid cycle (TCA cycle) and phenylalanine, tyrosine and tryptophan biosynthesis. These results provide a further understanding of milk metabolome altered by clinical mastitis, which can be used as a reference for the further milk metabolome investigations.

scholarly journals Production of succinate by engineered strains of Synechocystis PCC 6803 overexpressing phosphoenolpyruvate carboxylase and a glyoxylate shunt

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Claudia Durall ◽  
Kateryna Kukil ◽  
Jeffrey A. Hawkes ◽  
Alessia Albergati ◽  
Peter Lindblad ◽  
...  
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Cell Metabolism ◽  
Tca Cycle ◽  
Malate Synthase ◽  
Glyoxylate Shunt ◽  
Control Strain ◽  
Genes Encoding ◽  
Pcc 6803

Abstract Background Cyanobacteria are promising hosts for the production of various industrially important compounds such as succinate. This study focuses on introduction of the glyoxylate shunt, which is naturally present in only a few cyanobacteria, into Synechocystis PCC 6803. In order to test its impact on cell metabolism, engineered strains were evaluated for succinate accumulation under conditions of light, darkness and anoxic darkness. Each condition was complemented by treatments with 2-thenoyltrifluoroacetone, an inhibitor of succinate dehydrogenase enzyme, and acetate, both in nitrogen replete and deplete medium. Results We were able to introduce genes encoding the glyoxylate shunt, aceA and aceB, encoding isocitrate lyase and malate synthase respectively, into a strain of Synechocystis PCC 6803 engineered to overexpress phosphoenolpyruvate carboxylase. Our results show that complete expression of the glyoxylate shunt results in higher extracellular succinate accumulation compared to the wild type control strain after incubation of cells in darkness and anoxic darkness in the presence of nitrate. Addition of the inhibitor 2-thenoyltrifluoroacetone increased succinate titers in all the conditions tested when nitrate was available. Addition of acetate in the presence of the inhibitor further increased the succinate accumulation, resulting in high levels when phosphoenolpyruvate carboxylase was overexpressed, compared to control strain. However, the highest succinate titer was obtained after dark incubation of an engineered strain with a partial glyoxylate shunt overexpressing isocitrate lyase in addition to phosphoenolpyruvate carboxylase, with only 2-thenoyltrifluoroacetone supplementation to the medium. Conclusions Heterologous expression of the glyoxylate shunt with its central link to the tricarboxylic acid cycle (TCA) for acetate assimilation provides insight on the coordination of the carbon metabolism in the cell. Phosphoenolpyruvate carboxylase plays an important role in directing carbon flux towards the TCA cycle.

scholarly journals TCA Cycle and Fatty Acids Oxidation Reflect Early Cardiorenal Damage in Normoalbuminuric Subjects with Controlled Hypertension

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1100
Author(s):  
Aranzazu Santiago-Hernandez ◽  
Marta Martin-Lorenzo ◽  
Ariadna Martin-Blazquez ◽  
Gema Ruiz-Hurtado ◽  
Maria G Barderas ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Tricarboxylic Acid Cycle ◽  
Renin Angiotensin System ◽  
Roc Curves ◽  
Tca Cycle ◽  
Urinary Metabolites ◽  
Organ Damage ◽  
Fatty Acid Binding ◽  
Angiotensin System

Moderately increased albuminuria, defined by an albumin to creatinine ratio (ACR) > 30 mg/g, is an indicator of subclinical organ damage associated with a higher risk of cardiovascular and renal disease. Normoalbuminuric subjects are considered at no cardiorenal risk in clinical practice, and molecular changes underlying early development are unclear. To decipher subjacent mechanisms, we stratified the normoalbuminuria condition. A total of 37 hypertensive patients under chronic renin–angiotensin system (RAS) suppression with ACR values in the normoalbuminuria range were included and classified as control (C) (ACR < 10 mg/g) and high-normal (HN) (ACR = 10–30 mg/g). Target metabolomic analysis was carried out by liquid chromatography and mass spectrometry to investigate the role of the cardiorenal risk urinary metabolites previously identified. Besides this, urinary free fatty acids (FFAs), fatty acid binding protein 1 (FABP1) and nephrin were analyzed by colorimetric and ELISA assays. A Mann–Whitney test was applied, ROC curves were calculated and Spearman correlation analysis was carried out. Nine metabolites showed significantly altered abundance in HN versus C, and urinary FFAs and FABP1 increased in HN group, pointing to dysregulation in the tricarboxylic acid cycle (TCA) cycle and fatty acids β-oxidation. We showed here how cardiorenal metabolites associate with albuminuria, already in the normoalbuminuric range, evidencing early renal damage at a tubular level and suggesting increased β-oxidation to potentially counteract fatty acids overload in the HN range.

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