scholarly journals A Transcriptional Regulatory System of the S. cerevisiae OLE1 Gene Responds to Fatty Acid Species and Intracellular Amount, and not Simply Membrane Status

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Marshall Willey ◽  
Matt Ochs ◽  
Clara Busse ◽  
Virginia McDonough
Keyword(s):  
Fatty Acid ◽  
Membrane Fluidity ◽  
Regulatory System ◽  
Major Product ◽  
Subsequent Work ◽  
Transcriptional Regulatory ◽  
Initial Hypothesis ◽  
Stearoyl Coa Desaturase ◽  
Temperature And Growth ◽  
Fatty Acid Species

We examined the effects of unsaturated fatty acid (UFA) species and their concentration on the expression of OLE1, which encodes the stearoyl CoA desaturase, in Saccharomyces cerevisiae. We controlled the amount of UFA taken up by the cell by varying the concentration of tergitol in the medium. When cultured with 1 mM fatty acid in 0.1% tergitol, cells took up much more fatty acid than when cultured with the same concentration of fatty acid at 1% tergitol, although the amount incorporated was dependent on UFA species. For each fatty acid tested, we found that the higher uptake (0.1% tergitol condition) had a stronger impact on OLE1 regulation. A principal product of the desaturase 16:1∆9, and the nonnative UFA 18:2∆9,12, most strongly repressed the reporter construct OLE1-lacZ transcription, while the other major product of the desaturase, 18:1∆9, and the nonnative UFA 17:1∆10 caused a more diminished response. Based on these results, our initial hypothesis was that OLE1 was regulated in response to membrane fluidity; however, subsequent work does not support that idea; we have found that conditions that affect membrane fluidity such as growth temperature and growth with saturated or trans fatty acid supplementation, do not regulate OLE1 in the direction predicted by fluidity changes. We conclude that at least one signal that regulates OLE1 transcriptional expression is most likely based on the fatty acids themselves.

scholarly journals Menaquinone-mediated regulation of membrane fluidity is relevant for fitness of Listeria monocytogenes

2021 ◽  
Author(s):  
Alexander Flegler ◽  
Vanessa Kombeitz ◽  
André Lipski
Keyword(s):  
Fatty Acid ◽  
Listeria Monocytogenes ◽  
Membrane Fluidity ◽  
Low Temperatures ◽  
Lipid Membrane ◽  
Feedback Inhibition ◽  
Aromatic Amino Acids ◽  
Adaptation Effect ◽  
Membrane Composition ◽  
Lower Growth

AbstractListeria monocytogenes is a food-borne pathogen with the ability to grow at low temperatures down to − 0.4 °C. Maintaining cytoplasmic membrane fluidity by changing the lipid membrane composition is important during growth at low temperatures. In Listeria monocytogenes, the dominant adaptation effect is the fluidization of the membrane by shortening of fatty acid chain length. In some strains, however, an additional response is the increase in menaquinone content during growth at low temperatures. The increase of this neutral lipid leads to fluidization of the membrane and thus represents a mechanism that is complementary to the fatty acid-mediated modification of membrane fluidity. This study demonstrated that the reduction of menaquinone content for Listeria monocytogenes strains resulted in significantly lower resistance to temperature stress and lower growth rates compared to unaffected control cultures after growth at 6 °C. Menaquinone content was reduced by supplementation with aromatic amino acids, which led to a feedback inhibition of the menaquinone synthesis. Menaquinone-reduced Listeria monocytogenes strains showed reduced bacterial cell fitness. This confirmed the adaptive function of menaquinones for growth at low temperatures of this pathogen.

Novel polymorphisms in Stearoyl‐CoA Desaturase (SCD) and Fatty Acid Desaturase 2 (FADS2) in channel catfish ( Ictalurus punctatus, Rafinesque, 1818 )

2021 ◽  
Author(s):  
Oliva Mendoza‐Pacheco ◽  
Gaspar Manuel Parra‐Bracamonte ◽  
Xochitl Fabiola De la Rosa‐Reyna ◽  
Ana María Sifuentes‐Rincón ◽  
Isidro Otoniel Montelongo‐Alfaro ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Fatty Acid Desaturase ◽  
Stearoyl Coa Desaturase ◽  
Fatty Acid Desaturase 2

scholarly journals Investigation of the Membrane Fluidity Regulation of Fatty Acid Intracellular Distribution by Fluorescence Lifetime Imaging of Novel Polarity Sensitive Fluorescent Derivatives

2021 ◽  
Vol 22 (6) ◽  
pp. 3106
Author(s):  
Giada Bianchetti ◽  
Salome Azoulay-Ginsburg ◽  
Nimrod Yosef Keshet-Levy ◽  
Aviv Malka ◽  
Sofia Zilber ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Membrane Fluidity ◽  
Fluorescence Lifetime ◽  
Intracellular Distribution ◽  
Fluorescence Lifetime Imaging ◽  
Lifetime Imaging ◽  
Fatty Acid Derivatives ◽  
Polarity Sensitive

Free fatty acids are essential structural components of the cell, and their intracellular distribution and effects on membrane organelles have crucial roles in regulating the metabolism, development, and cell cycle of most cell types. Here we engineered novel fluorescent, polarity-sensitive fatty acid derivatives, with the fatty acid aliphatic chain of increasing length (from 12 to 18 carbons). As in the laurdan probe, the lipophilic acyl tail is connected to the environmentally sensitive dimethylaminonaphthalene moiety. The fluorescence lifetime imaging analysis allowed us to monitor the intracellular distribution of the free fatty acids within the cell, and to simultaneously examine how the fluidity and the microviscosity of the membrane environment influence their localization. Each of these probes can thus be used to investigate the membrane fluidity regulation of the correspondent fatty acid intracellular distribution. We observed that, in PC-12 cells, fluorescent sensitive fatty acid derivatives with increased chain length compartmentalize more preferentially in the fluid regions, characterized by a low microviscosity. Moreover, fatty acid derivatives with the longest chain compartmentalize in lipid droplets and lysosomes with characteristic lifetimes, thus making these probes a promising tool for monitoring lipophagy and related events.

scholarly journals A Novel CO-Responsive Transcriptional Regulator and Enhanced H2Production by an Engineered Thermococcus onnurineus NA1 Strain

2014 ◽  
Vol 81 (5) ◽  
pp. 1708-1714 ◽  
Author(s):  
Min-Sik Kim ◽  
Ae Ran Choi ◽  
Seong Hyuk Lee ◽  
Hae-Chang Jung ◽  
Seung Seob Bae ◽  
...  
Keyword(s):  
Production Rate ◽  
Gene Cluster ◽  
Type Strain ◽  
Wild Type Strain ◽  
Regulatory System ◽  
Transcriptional Regulator ◽  
Bioreactor Culture ◽  
Wild Type ◽  
Content Type ◽  
Transcriptional Regulatory

ABSTRACTGenome analysis revealed the existence of a putative transcriptional regulatory system governing CO metabolism inThermococcus onnurineusNA1, a carboxydotrophic hydrogenogenic archaeon. The regulatory system is composed of CorQ with a 4-vinyl reductase domain and CorR with a DNA-binding domain of the LysR-type transcriptional regulator family in close proximity to the CO dehydrogenase (CODH) gene cluster. Homologous genes of the CorQR pair were also found in the genomes ofThermococcusspecies and “CandidatusKorarchaeum cryptofilum” OPF8. In-frame deletion of eithercorQorcorRcaused a severe impairment in CO-dependent growth and H2production. WhencorQandcorRdeletion mutants were complemented by introducing thecorQRgenes under the control of a strong promoter, the mRNA and protein levels of the CODH gene were significantly increased in a ΔCorR strain complemented with integratedcorQR(ΔCorR/corQR↑) compared with those in the wild-type strain. In addition, the ΔCorR/corQR↑strain exhibited a much higher H2production rate (5.8-fold) than the wild-type strain in a bioreactor culture. The H2production rate (191.9 mmol liter−1h−1) and the specific H2production rate (249.6 mmol g−1h−1) of this strain were extremely high compared with those of CO-dependent H2-producing prokaryotes reported so far. These results suggest that thecorQRgenes encode a positive regulatory protein pair for the expression of a CODH gene cluster. The study also illustrates that manipulation of the transcriptional regulatory system can improve biological H2production.

scholarly journals Quorum Sensing: a Transcriptional Regulatory System Involved in the Pathogenicity of Burkholderia mallei

2004 ◽  
Vol 72 (11) ◽  
pp. 6589-6596 ◽  
Author(s):  
Ricky L. Ulrich ◽  
David DeShazer ◽  
Harry B. Hines ◽  
Jeffrey A. Jeddeloh
Keyword(s):  
Quorum Sensing ◽  
Virulence Factor ◽  
Regulatory System ◽  
In Silico Analysis ◽  
Homoserine Lactone ◽  
Burkholderia Mallei ◽  
Wild Type ◽  
Transcriptional Regulatory ◽  
A Cell

ABSTRACT Numerous gram-negative bacterial pathogens regulate virulence factor expression by using a cell density mechanism termed quorum sensing (QS). An in silico analysis of the Burkholderia mallei ATCC 23344 genome revealed that it encodes at least two luxI and four luxR homologues. Using mass spectrometry, we showed that wild-type B. mallei produces the signaling molecules N-octanoyl-homoserine lactone and N-decanoyl-homoserine lactone. To determine if QS is involved in the virulence of B. mallei, we generated mutations in each putative luxIR homologue and tested the pathogenicities of the derivative strains in aerosol BALB/c mouse and intraperitoneal hamster models. Disruption of the B. mallei QS alleles, especially in RJ16 (bmaII) and RJ17 (bmaI3), which are luxI mutants, significantly reduced virulence, as indicated by the survival of mice who were aerosolized with 104 CFU (10 50% lethal doses [LD50s]). For the B. mallei transcriptional regulator mutants (luxR homologues), mutation of the bmaR5 allele resulted in the most pronounced decrease in virulence, with 100% of the challenged animals surviving a dose of 10 LD50s. Using a Syrian hamster intraperitoneal model of infection, we determined the LD50s for wild-type B. mallei and each QS mutant. An increase in the relative LD50 was found for RJ16 (bmaI1) (>967 CFU), RJ17 (bmaI3) (115 CFU), and RJ20 (bmaR5) (151 CFU) compared to wild-type B. mallei (<13 CFU). These findings demonstrate that B. mallei carries multiple luxIR homologues that either directly or indirectly regulate the biosynthesis of an essential virulence factor(s) that contributes to the pathogenicity of B. mallei in vivo.

scholarly journals Functional States of the Genome-Scale Escherichia Coli Transcriptional Regulatory System

2009 ◽  
Vol 5 (6) ◽  
pp. e1000403 ◽  
Author(s):  
Erwin P. Gianchandani ◽  
Andrew R. Joyce ◽  
Bernhard Ø. Palsson ◽  
Jason A. Papin
Keyword(s):  
Escherichia Coli ◽  
Regulatory System ◽  
Transcriptional Regulatory ◽  
Functional States ◽  
Genome Scale

Seasonal Variation in Plasma Nonesterified Fatty Acids of Lake Sturgeon (Acipenser fulvescens) in the Vicinity of Hydroelectric Facilities

1993 ◽  
Vol 50 (11) ◽  
pp. 2440-2447 ◽  
Author(s):  
R. S. McKinley ◽  
T. D. Singer ◽  
J. S. Ballantyne ◽  
G. Power
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lake Sturgeon ◽  
Acipenser Fulvescens ◽  
Total Plasma ◽  
Nefa Concentration ◽  
Plasma Nefa ◽  
Nonesterified Fatty Acids ◽  
Plasma Nefa Concentration ◽  
Fatty Acid Species

To establish the effects of hydroelectric generation on the health of lake sturgeon (Acipenser fulvescens), seasonal variations in plasma nonesterified fatty acids (NEFAs) upstream and downstream from hydroelectric stations were measured over a 2-yr period. Plasma NEFA profiles were also compared up- and downstream of the stations for differences in utilization of individual NEFA species as substrates for lipid oxidation. Significantly higher levels of total plasma NEFA were found in lake sturgeon upstream (2355 ± 395.9 nmol/mL) compared with those downstream (798 ± 133.5 nmol/mL) of the generating stations during the spring. The NEFA profiles for several key fatty acid species differed significantly among seasons up- and downstream of the facilities. In particular, during spring and summer, the levels of oleic acid (18:1n9) were highest upstream of the stations and levels of a polyunsaturated fatty acid, docosahexaenoic acid (22:6n3), were higher below rather than above the stations. The differences in plasma NEFA concentration may be attributed to altered nutritional status due to the varying flow regime located downstream of the hydroelectric stations.

scholarly journals Acetate represents a major product of heptanoate and octanoate β-oxidation in hepatocytes isolated from neonatal piglets

1996 ◽  
Vol 318 (1) ◽  
pp. 235-240 ◽  
Author(s):  
Xi LIN ◽  
Sean H. ADAMS ◽  
Jack ODLE
Keyword(s):  
Fatty Acid ◽  
Organic Acids ◽  
Chain Length ◽  
Ketone Bodies ◽  
Krebs Cycle ◽  
Major Product ◽  
Carbon Accounting ◽  
Minor Amount ◽  
Fatty Acid Carbon ◽  
Carboxyl Carbon

An experiment was conducted to explore the nature of the radiolabel distribution in acid-soluble products (ASPs) resulting from the oxidation of [1-14C]C7:0 or C8:0 by isolated piglet hepatocytes. The differences between odd and even chain-length and the impacts of valproate and malonate upon the rate of β-oxidation and ASP characteristics were tested. A minor amount of fatty acid carboxyl carbon (⩽ 10% of organic acids identified by radio-HPLC) accumulated in ketone bodies regardless of chain-length or inhibitor used. In all cases, acetate represented the major reservoir of carboxyl carbon, accounting for 60–70% of radiolabel in identified organic acids. Cells given [1-14C]C7:0 accumulated 85% more carboxyl carbon in Krebs cycle intermediates when compared with C8:0, while accumulation in acetate was unaffected. The results are consistent with the hypothesis that anaplerosis from odd-carbon fatty acids affects the oxidative fate of fatty acid carbon. The piglet appears unique in that non-ketogenic routes of fatty acid carbon flow (i.e. acetogenesis) predominate in the liver of this species.

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