scholarly journals Dynamics of the Streptococcus gordonii Transcriptome in Response to Medium, Salivary α-Amylase, and Starch

2015 ◽  
Vol 81 (16) ◽  
pp. 5363-5374 ◽  
Author(s):  
Elaine M. Haase ◽  
Xianghui Feng ◽  
Jiachuan Pan ◽  
Jeffrey C. Miecznikowski ◽  
Frank A. Scannapieco
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Environmental Conditions ◽  
Acid Synthesis ◽  
Oral Bacteria ◽  
Methionine Sulfoxide Reductase ◽  
Tooth Surface ◽  
Dependent Manner ◽  
Streptococcus Gordonii ◽  
Content Type

ABSTRACTStreptococcus gordonii, a primary colonizer of the tooth surface, interacts with salivary α-amylase via amylase-binding protein A (AbpA). This enzyme hydrolyzes starch to glucose, maltose, and maltodextrins that can be utilized by various oral bacteria for nutrition. Microarray studies demonstrated that AbpA modulates gene expression in response to amylase, suggesting that the amylase-streptococcal interaction may function in ways other than nutrition. The goal of this study was to explore the role of AbpA in gene regulation through comparative transcriptional profiling of wild-type KS1 and AbpA−mutant KS1ΩabpAunder various environmental conditions. A portion of the total RNA isolated from mid-log-phase cells grown in 5% CO2in (i) complex medium with or without amylase, (ii) defined medium (DM) containing 0.8% glucose with/without amylase, and (iii) DM containing 0.2% glucose and amylase with or without starch was reverse transcribed to cDNA and the rest used for RNA sequencing. Changes in the expression of selected genes were validated by quantitative reverse transcription-PCR. Maltodextrin-associated genes, fatty acid synthesis genes and competence genes were differentially expressed in a medium-dependent manner. Genes in another cluster containing a putative histidine kinase/response regulator, peptide methionine sulfoxide reductase, thioredoxin protein, lipoprotein, and cytochromec-type protein were downregulated in KS1ΩabpAunder all of the environmental conditions tested. Thus, AbpA appears to modulate genes associated with maltodextrin utilization/transport and fatty acid synthesis. Importantly, in all growth conditions AbpA was associated with increased expression of a potential two-component signaling system associated with genes involved in reducing oxidative stress, suggesting a role in signal transduction and stress tolerance.

scholarly journals Response of Fatty Acid Synthesis Genes to the Binding of Human Salivary Amylase by Streptococcus gordonii

2012 ◽  
Vol 78 (6) ◽  
pp. 1865-1875 ◽  
Author(s):  
Anna E. Nikitkova ◽  
Elaine M. Haase ◽  
M. Margaret Vickerman ◽  
Steven R. Gill ◽  
Frank A. Scannapieco
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Protein A ◽  
Acid Synthesis ◽  
Differentially Expressed ◽  
Streptococcus Gordonii ◽  
Bacterial Survival ◽  
Salivary Amylase ◽  
Content Type

ABSTRACTStreptococcus gordonii, an important primary colonizer of dental plaque biofilm, specifically binds to salivary amylase via the surface-associated amylase-binding protein A (AbpA). We hypothesized that a function of amylase binding toS. gordoniimay be to modulate the expression of chromosomal genes, which could influence bacterial survival and persistence in the oral cavity. Gene expression profiling by microarray analysis was performed to detect genes inS. gordoniistrain CH1 that were differentially expressed in response to the binding of purified human salivary amylase versus exposure to purified heat-denatured amylase. Selected genes found to be differentially expressed were validated by quantitative reverse transcription-PCR (qRT-PCR). Five genes from the fatty acid synthesis (FAS) cluster were highly (10- to 35-fold) upregulated inS. gordoniiCH1 cells treated with native amylase relative to those treated with denatured amylase. AnabpA-deficient strain ofS. gordoniiexposed to amylase failed to show a response in FAS gene expression similar to that observed in the parental strain. Predicted phenotypic effects of amylase binding toS. gordoniistrain CH1 (associated with increased expression of FAS genes, leading to changes in fatty acid synthesis) were noted; these included increased bacterial growth, survival at low pH, and resistance to triclosan. These changes were not observed in the amylase-exposedabpA-deficient strain, suggesting a role for AbpA in the amylase-induced phenotype. These results provide evidence that the binding of salivary amylase elicits a differential gene response inS. gordonii, resulting in a phenotypic adjustment that is potentially advantageous for bacterial survival in the oral environment.

scholarly journals Thailandamide, a Fatty Acid Synthesis Antibiotic That Is Coexpressed with a Resistant Target Gene

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Christopher E. Wozniak ◽  
Zhenjian Lin ◽  
Eric W. Schmidt ◽  
Kelly T. Hughes ◽  
Theodore G. Liou
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Target Gene ◽  
Gene Clusters ◽  
Acid Synthesis ◽  
Inducible Promoter ◽  
Content Type ◽  
Uncharacterized Gene ◽  
Fatty Acid Synthesis Pathway ◽  
Genetic Techniques

ABSTRACTMicrobes encode many uncharacterized gene clusters that may produce antibiotics and other bioactive small molecules. Methods for activating these genes are needed to explore their biosynthetic potential. A transposon containing an inducible promoter was randomly inserted into the genome of the soil bacteriumBurkholderia thailandensisto induce antibiotic expression. This screen identified the polyketide/nonribosomal peptide thailandamide as an antibiotic and discovered its regulator, AtsR. Mutants ofSalmonellaresistant to thailandamide had mutations in theaccAgene for acetyl coenzyme A (acetyl-CoA) carboxylase, which is one of the first enzymes in the fatty acid synthesis pathway. A second copy ofaccAin the thailandamide synthesis gene cluster keepsB. thailandensisresistant to its own antibiotic. These genetic techniques will likely be powerful tools for discovering other unusual antibiotics.

scholarly journals Stimulation of hepatic lipogenesis and acetyl-coenzyme A carboxylase by vasopressin

1981 ◽  
Vol 198 (3) ◽  
pp. 485-490 ◽  
Author(s):  
F Assimacopoulos-Jeannet ◽  
R M Denton ◽  
B Jeanrenaud
Keyword(s):  
Fatty Acid ◽  
Dose Response ◽  
Fatty Acid Synthesis ◽  
Response Curve ◽  
Acid Synthesis ◽  
Dose Response Curve ◽  
Dependent Manner ◽  
Hepatic Lipogenesis ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa

The effect of vasopressin on the short-term regulation of fatty acid synthesis was studied in isolated hepatocytes from rats fed ad libitum. Vasopressin stimulates fatty acid synthesis by 30-110%. This increase is comparable with that obtained with insulin. Angiotensin also stimulates fatty acid synthesis, whereas phenylephrine does not. The dose-response curve for vasopressin-stimulated lipogenesis is similar to the dose-response curve for glycogenolysis and release of lactate plus pyruvate. Vasopression also stimulates acetyl-CoA carboxylase activity in a dose-dependent manner. Vasopressin does not relieve glucagon-inhibited lipogenesis, whereas insulin does. The action of vasopressin on hepatic lipogenesis is decreased, but not suppressed, in Ca2+-depleted hepatocytes. The results suggest that vasopressin acts on lipogenesis by increasing availability of lipogenic substrate (lactate + pyruvate) and by activating acetyl-CoA carboxylase.

LIF and CNTF, which share the gp130 transduction system, stimulate hepatic lipid metabolism in rats

1996 ◽  
Vol 271 (3) ◽  
pp. E521-E528 ◽  
Author(s):  
K. Nonogaki ◽  
X. M. Pan ◽  
A. H. Moser ◽  
J. Shigenaga ◽  
I. Staprans ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Acid Synthesis ◽  
Interleukin 4 ◽  
Dependent Manner ◽  
Hepatic Triglyceride ◽  
Serum Triglycerides ◽  
Triglyceride Secretion

We determined the effects of leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF) on lipid metabolism in intact rats. Administration of LIF and CNTF increased serum triglycerides in a dose-dependent manner with peak values at 2 h. The effects of LIF and CNTF on serum cholesterol were very small, and serum glucose was unaffected. Both LIF and CNTF stimulated hepatic triglyceride secretion, hepatic de novo fatty acid synthesis, and lipolysis. Pretreatment with phenylisopropyl adenosine, which inhibits lipolysis, partially inhibited LIF- and CNTF-induced hypertriglyceridemia. Interleukin-4, which inhibits cytokine-induced hepatic fatty acid synthesis, also partially inhibited LIF- and CNTF-induced hypertriglyceridemia. These results indicate that both lipolysis and de novo fatty acid synthesis play a role in providing fatty acids for the increase in hepatic triglyceride secretion. Neither indomethacin nor adrenergic receptor antagonists affected the hypertriglyceridemia. The combination of LIF plus CNTF showed no additive effects consistent with the action of both cytokines through the gp130 transduction system. Thus LIF and CNTF have similar effects on lipid metabolism; they join a growing list of cytokines that stimulate hepatic triglyceride secretion and may mediate the changes in lipid metabolism that accompany the acute phase response.

scholarly journals Staphylococcus aureus Fatty Acid Auxotrophs Do Not Proliferate in Mice

2013 ◽  
Vol 57 (11) ◽  
pp. 5729-5732 ◽  
Author(s):  
Joshua B. Parsons ◽  
Matthew W. Frank ◽  
Jason W. Rosch ◽  
Charles O. Rock
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Normal Growth ◽  
Acid Synthesis ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Content Type

ABSTRACTInactivation of acetyl-coenzyme A (acetyl-CoA) carboxylase confers resistance to fatty acid synthesis inhibitors inStaphylococcus aureuson media supplemented with fatty acids. The addition ofanteiso-fatty acids (1 mM) plus lipoic acid supports normal growth of ΔaccDstrains, but supplementation with mammalian fatty acids was less efficient. Mice infected with strain RN6930 developed bacteremia, but bacteria were not detected in mice infected with its ΔaccDderivative.S. aureusbacteria lacking acetyl-CoA carboxylase can be propagatedin vitrobut were unable to proliferate in mice, suggesting that the acquisition of inactivating mutations in this enzyme is not a mechanism for the evasion of fatty acid synthesis inhibitors.

scholarly journals Taurine-Mediated IDOL Contributes to Resolution of Streptococcus uberis Infection

2021 ◽  
Vol 89 (5) ◽  
Author(s):  
Zhixin Wan ◽  
Riguo Lan ◽  
Yilin Zhou ◽  
Yuanyuan Xu ◽  
Zhenglei Wang ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Bacterial Load ◽  
Critical Role ◽  
Acid Synthesis ◽  
Content Type ◽  
Streptococcus Uberis

ABSTRACT Metabolic alterations occur in pathogenic infections, but the role of lipid metabolism in the progression of bacterial mastitis is unclear. Cross talk between lipid droplets (LDs) and invading bacteria occurs, and targeting of de novo lipogenesis inhibits pathogen reproduction. In this study, we investigate the role(s) of lipid metabolism in mammary cells during Streptococcus uberis infection. Our results indicate that S. uberis induces the synthesis of fatty acids and production of LDs. Importantly, taurine reduces fatty acid synthesis, the abundance of LDs and the in vitro bacterial load of S. uberis. These changes are mediated, at least partly, by the E3 ubiquitin ligase IDOL, which is associated with the degradation of low-density lipoprotein receptors (LDLRs). We have identified a critical role for IDOL-mediated fatty acid synthesis in bacterial infection, and we suggest that taurine may be an effective prophylactic or therapeutic strategy for preventing S. uberis mastitis.

scholarly journals NovelXanthomonas campestrisLong-Chain-Specific 3-Oxoacyl-Acyl Carrier Protein Reductase Involved in Diffusible Signal Factor Synthesis

mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Zhe Hu ◽  
Huijuan Dong ◽  
Jin-Cheng Ma ◽  
Yonghong Yu ◽  
Kai-Hui Li ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Xanthomonas Campestris ◽  
Octanoic Acid ◽  
Acyl Carrier Protein ◽  
Acid Synthesis ◽  
Carrier Protein ◽  
Content Type ◽  
Diffusible Signal Factor ◽  
Acyl Chains

ABSTRACTThe precursors of the diffusible signal factor (DSF) family signals ofXanthomonas campestrispv.campestrisare 3-hydroxyacyl-acyl carrier protein (3-hydroxyacyl-ACP) thioesters having acyl chains of 12 to 13 carbon atoms produced by the fatty acid biosynthetic pathway. We report a novel 3-oxoacyl-ACP reductase encoded by theX. campestrispv.campestrisXCC0416 gene (fabG2), which is unable to participate in the initial steps of fatty acyl synthesis. This was shown by the failure of FabG2 expression to allow growth at the nonpermissive temperature of anEscherichia colifabGtemperature-sensitive strain. However, when transformed into theE. colistrain together with a plasmid bearing theVibrio harveyiacyl-ACP synthetase gene (aasS), growth proceeded, but only when the medium contained octanoic acid.In vitroassays showed that FabG2 catalyzes the reduction of long-chain (≥C8) 3-oxoacyl-ACPs to 3-hydroxyacyl-ACPs but is only weakly active with shorter-chain (C4, C6) substrates. FabG1, the housekeeping 3-oxoacyl-ACP reductase encoded within the fatty acid synthesis gene cluster, could be deleted in a strain that overexpressedfabG2but only in octanoic acid-supplemented media. Growth of theX. campestrispv.campestrisΔfabG1strain overexpressingfabG2requiredfabHfor growth with octanoic acid, indicating that octanoyl coenzyme A is elongated byX. campestrispv.campestrisfabH. Deletion offabG2reduced DSF family signal production, whereas overproduction of either FabG1 or FabG2 in the ΔfabG2strain restored DSF family signal levels.IMPORTANCEQuorum sensing mediated by DSF signaling molecules regulates pathogenesis in several different phytopathogenic bacteria, includingXanthomonas campestrispv.campestris. DSF signaling also plays a key role in infection by the human pathogenBurkholderia cepacia. The acyl chains of the DSF molecules are diverted and remodeled from a key intermediate of the fatty acid synthesis pathway. We report aXanthomonas campestrispv.campestrisfatty acid synthesis enzyme, FabG2, of novel specificity that seems tailored to provide DSF signaling molecule precursors.

scholarly journals Enterococcus faecalisEncodes an Atypical Auxiliary Acyl Carrier Protein Required for Efficient Regulation of Fatty Acid Synthesis by Exogenous Fatty Acids

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Lei Zhu ◽  
Qi Zou ◽  
Xinyun Cao ◽  
John E. Cronan
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Type Strain ◽  
Wild Type Strain ◽  
De Novo ◽  
Acid Synthesis ◽  
Wild Type ◽  
Content Type

ABSTRACTAcyl carrier proteins (ACPs) play essential roles in the synthesis of fatty acids and transfer of long fatty acyl chains into complex lipids. TheEnterococcus faecalisgenome contains two annotatedacpgenes, calledacpAandacpB. AcpA is encoded within the fatty acid synthesis (fab) operon and appears essential. In contrast, AcpB is an atypical ACP, having only 30% residue identity with AcpA, and is not essential. Deletion ofacpBhas no effect onE. faecalisgrowth orde novofatty acid synthesis in media lacking fatty acids. However, unlike the wild-type strain, where growth with oleic acid resulted in almost complete blockage ofde novofatty acid synthesis, theΔacpBstrain largely continuedde novofatty acid synthesis under these conditions. Blockage in the wild-type strain is due to repression offaboperon transcription, leading to levels of fatty acid synthetic proteins (including AcpA) that are insufficient to supportde novosynthesis. Transcription of thefaboperon is regulated by FabT, a repressor protein that binds DNA only when it is bound to an acyl-ACP ligand. Since AcpA is encoded in thefaboperon, its synthesis is blocked when the operon is repressed andacpAthus cannot provide a stable supply of ACP for synthesis of the acyl-ACP ligand required for DNA binding by FabT. In contrast to AcpA,acpBtranscription is unaffected by growth with exogenous fatty acids and thus provides a stable supply of ACP for conversion to the acyl-ACP ligand required for repression by FabT. Indeed,ΔacpBandΔfabTstrains have essentially the samede novofatty acid synthesis phenotype in oleic acid-grown cultures, which argues that neither strain can form the FabT-acyl-ACP repression complex. Finally, acylated derivatives of both AcpB and AcpA were substrates for theE. faecalisenoyl-ACP reductases and forE. faecalisPlsX (acyl-ACP; phosphate acyltransferase).IMPORTANCEAcpB homologs are encoded by many, but not all, lactic acid bacteria (Lactobacillales), including many members of the human microbiome. The mechanisms regulating fatty acid synthesis by exogenous fatty acids play a key role in resistance of these bacteria to those antimicrobials targeted at fatty acid synthesis enzymes. Defective regulation can increase resistance to such inhibitors and also reduce pathogenesis.

scholarly journals The Bactericidal Fatty Acid Mimetic 2CCA-1 Selectively Targets Pneumococcal Extracellular Polyunsaturated Fatty Acid Metabolism

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. e03027-20
Author(s):  
Elisabeth Reithuber ◽  
Priyanka Nannapaneni ◽  
Olena Rzhepishevska ◽  
Anders E. G. Lindgren ◽  
Oleksandr Ilchenko ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Streptococcus Pneumoniae ◽  
Fatty Acid Synthesis ◽  
Acid Metabolism ◽  
Acid Synthesis ◽  
Endogenous Fatty Acid ◽  
Content Type ◽  
Endogenous Fatty Acid Synthesis ◽  
Phospholipid Species

ABSTRACTStreptococcus pneumoniae, a major cause of pneumonia, sepsis, and meningitis worldwide, has the nasopharynges of small children as its main ecological niche. Depletion of pneumococci from this niche would reduce the disease burden and could be achieved using small molecules with narrow-spectrum antibacterial activity. We identified the alkylated dicyclohexyl carboxylic acid 2CCA-1 as a potent inducer of autolysin-mediated lysis of S. pneumoniae, while having low activity against Staphylococcus aureus. 2CCA-1-resistant strains were found to have inactivating mutations in fakB3, known to be required for uptake of host polyunsaturated fatty acids, as well as through inactivation of the transcriptional regulator gene fabT, vital for endogenous, de novo fatty acid synthesis regulation. Structure activity relationship exploration revealed that, besides the central dicyclohexyl group, the fatty acid-like structural features of 2CCA-1 were essential for its activity. The lysis-inducing activity of 2CCA-1 was considerably more potent than that of free fatty acids and required growing bacteria, suggesting that 2CCA-1 needs to be metabolized to exert its antimicrobial activity. Total lipid analysis of 2CCA-1 treated bacteria identified unique masses that were modeled to 2CCA-1 containing lysophosphatidic and phosphatidic acid in wild-type but not in fakB3 mutant bacteria. This suggests that 2CCA-1 is metabolized as a fatty acid via FakB3 and utilized as a phospholipid building block, leading to accumulation of toxic phospholipid species. Analysis of FabT-mediated fakB3 expression elucidates how the pneumococcus could ensure membrane homeostasis and concurrent economic use of host-derived fatty acids.IMPORTANCE Fatty acid biosynthesis is an attractive antibiotic target, as it affects the supply of membrane phospholipid building blocks. In Streptococcus pneumoniae, it is not sufficient to target only the endogenous fatty acid synthesis machinery, as uptake of host fatty acids may bypass this inhibition. Here, we describe a small-molecule compound, 2CCA-1, with potent bactericidal activity that upon interactions with the fatty acid binding protein FakB3, which is present in a limited number of Gram-positive species, becomes metabolized and incorporated as a toxic phospholipid species. Resistance to 2CCA-1 developed specifically in fakB3 and the regulatory gene fabT. These mutants reveal a regulatory connection between the extracellular polyunsaturated fatty acid metabolism and endogenous fatty acid synthesis in S. pneumoniae, which could ensure balance between efficient scavenging of host polyunsaturated fatty acids and membrane homeostasis. The data might be useful in the identification of narrow-spectrum treatment strategies to selectively target members of the Lactobacillales such as S. pneumoniae.

scholarly journals Staphylococcus aureusUtilizes Host-Derived Lipoprotein Particles as Sources of Fatty Acids

2018 ◽  
Vol 200 (11) ◽  
Author(s):  
Phillip C. Delekta ◽  
John C. Shook ◽  
Todd A. Lydic ◽  
Martha H. Mulks ◽  
Neal D. Hammer
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Acid Synthesis ◽  
Low Density ◽  
Content Type ◽  
Lipoprotein Particles ◽  
Bacterial Fatty Acid

ABSTRACTMethicillin-resistantStaphylococcus aureus(MRSA) is a threat to global health. Consequently, much effort has focused on the development of new antimicrobials that target novel aspects ofS. aureusphysiology. Fatty acids are required to maintain cell viability, and bacteria synthesize fatty acids using the type II fatty acid synthesis (FASII) pathway. FASII is significantly different from human fatty acid synthesis, underscoring the therapeutic potential of inhibiting this pathway. However, many Gram-positive pathogens incorporate exogenous fatty acids, bypassing FASII inhibition and leaving the clinical potential of FASII inhibitors uncertain. Importantly, the source(s) of fatty acids available to pathogens within the host environment remains unclear. Fatty acids are transported throughout the body by lipoprotein particles in the form of triglycerides and esterified cholesterol. Thus, lipoproteins, such as low-density lipoprotein (LDL), represent a potentially rich source of exogenous fatty acids forS. aureusduring infection. We sought to test the ability of LDLs to serve as a fatty acid source forS. aureusand show that cells cultured in the presence of human LDLs demonstrate increased tolerance to the FASII inhibitor triclosan. Using mass spectrometry, we observed that host-derived fatty acids present in the LDLs are incorporated into the staphylococcal membrane and that tolerance to triclosan is facilitated by the fatty acid kinase A, FakA, and Geh, a triacylglycerol lipase. Finally, we demonstrate that human LDLs support the growth ofS. aureusfatty acid auxotrophs. Together, these results suggest that human lipoprotein particles are a viable source of exogenous fatty acids forS. aureusduring infection.IMPORTANCEInhibition of bacterial fatty acid synthesis is a promising approach to combating infections caused byS. aureusand other human pathogens. However,S. aureusincorporates exogenous fatty acids into its phospholipid bilayer. Therefore, the clinical utility of targeting bacterial fatty acid synthesis is debated. Moreover, the fatty acid reservoir(s) exploited byS. aureusis not well understood. Human low-density lipoprotein particles represent a particularly abundantin vivosource of fatty acids and are present in tissues thatS. aureuscolonizes. Herein, we establish thatS. aureusis capable of utilizing the fatty acids present in low-density lipoproteins to bypass both chemical and genetic inhibition of fatty acid synthesis. These findings imply thatS. aureustargets LDLs as a source of fatty acids during pathogenesis.

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