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PubMed1990

Determination by photoaffinity labelling of the hydrophobic part of the binding site for acyl-CoA esters on acyl-CoA-binding protein from bovine liver.

Acyl-CoA esters containing the photoreactive acids 12-(4'-azido-2'-nitrophenoxy)[1-14C]dodecanoic acid ([14C]AND-acid) or N-(4'-azido-2'-nitro-[3'-5'-3H]phenyl)-12-aminododecanoic acid ([3H]NANPA-acid) were synthesized. The photoreactive acyl-CoA esters could be bound to bovine acyl-CoA-binding protein (ACBP) and photocrosslinked to the protein. The photocrosslinked acyl-CoA-ACBP complex was separated from unlabelled ACBP on reverse-phase h.p.l.c. and the purified complex was digested with trypsin, Staphylococcus aureus V8 proteinase or endoproteinase Asp-N. By four independent peptide maps it was shown that the amino acids taking part in forming the hydrophobic binding site for acyl-CoA esters in bovine ACBP are located on the peptide segment from Asp21 to Asp38. Both photoreactive acyl-CoA esters used in this study labelled strongly in the segment from Tyr28 to Ala34. 12-(4'-Azido-2'-nitrophenoxy)[1-14C]-dodecanoyl-CoA ([14C]AND-CoA) also introduced a label at position Asp38, but o labelling was found before Ser29. In contrast, N-(4'-azido-2'-nitro[3',5'-3H]phenyl)-12-aminododecanoyl-CoA [3H]NANPA-CoA) also labelled the segment from Asp21 to Tyr28. The difference in labelling by the two photoreactive ligands is most likely caused by different mobility of the arylazido group when linked to the fatty acid either through a phenolic O- or an anilinic N- bond.

Acyl Coenzyme A↗
PubMed1991

Characterization of the binding sites for dicarboxylic acids on bovine serum albumin.

Dicarboxylic acids are prominent features of several diseases, including Reye's syndrome and inborn errors of mitochondrial and peroxisomal fatty acid oxidation. Moreover, dicarboxylic acids are potentially toxic to cellular processes. Previous studies [Tonsgard, Mendelson & Meredith (1988) J. Clin. Invest. 82, 1567-1573] demonstrated that long-chain dicarboxylic acids have a single high-affinity binding site and between one and three lower-affinity sites on albumin. Medium-chain-length dicarboxylic acids have a single low-affinity site. We further characterized dicarboxylic acid binding to albumin in order to understand the potential effects of drugs and other ligands on dicarboxylic acid binding and toxicity. Progesterone and oleate competitively inhibit octadecanedioic acid binding to the single high-affinity site. Octanoate inhibits binding to the low-affinity sites. Dansylated probes for subdomain 2AB inhibit dodecanedioic acid binding whereas probes for subdomain 3AB do not. In contrast, low concentrations of octadecanedioic acid inhibit the binding of dansylated probes to subdomain 3AB and 2AB. L-Tryptophan, which binds in subdomain 3AB, inhibits hexadecanedioic acid binding but has no effect on dodecanedioic acid. Bilirubin and acetylsalicylic acid, which bind in subdomain 2AB, inhibit the binding of medium-chain and long-chain dicarboxylic acids. Our results suggest that long-chain dicarboxylic acids bind in subdomains 2C, 3AB and 2AB. The single low-affinity binding site for medium-chain dicarboxylic acids is in subdomain 2AB. These studies suggest that dicarboxylic acids are likely to be unbound in disease states and may be potentially toxic.

Acylation↗
PubMed2000

Plasma membrane polarity of polymorphonuclear leucocytes from children with primary ciliary dyskinesia.

BACKGROUND: Polymorphonuclear leucocytes (PMN) from subjects with primary ciliary dyskinesia (PCD) can have abnormal locomotory systems. The locomotory activity of PMN is the result of biochemical events mediated by the plasma membrane. In this study we investigated plasma membrane polarity of PMN from children with PCD. DESIGN: Membrane polarity was studied in 11 children with PCD and in healthy controls by measuring the steady-state fluorescence excitation and emission spectra of 2-dimethylamino[6-lauroyl]naphthalene (Laurdan), which is known to be incorporated at the hydrophobic-hydrophilic interface of the bilayer, displaying spectral sensitivity to the polarity of its surroundings. Laurdan shows a marked steady-state emission red shift in polar solvents, with respect to nonpolar solvents. Moreover, the effect of the microtubule disassembling agent colchicine on PMN membrane polarity was evaluated. RESULT: Our results show a red shift of the fluorescence excitation and emission spectra of Laurdan in PMN from the PCD group with respect to the control group. These data indicate an increase in membrane polarity of PMN from the PCD group. Treatment of PMN with colchicine induced a red shift in the Laurdan excitation and emission spectra with the same trend observed in PMN from the PCD group. CONCLUSION: PMN from children with PCD are characterized by an increased plasma membrane polarity. These changes could be the basis of the modifications in the locomotory activities of PMN. The observed alterations may be attributed to abnormalities in the cytoskeleton.

2-Naphthylamine↗
PubMed1999

Inhibition of Bacillus licheniformis spore growth in milk by nisin, monolaurin, and pH combinations.

The effects of nisin and monolaurin, alone and in combination, were investigated on Bacillus licheniformis spores in milk at 37 degrees C. In the absence of inhibitors, germinated spores developed into growing vegetative cells and started sporulation at the end of the exponential phase. In the presence of nisin (25 IU ml-1), spore outgrowth was inhibited (4 log10 reduction at 10 h). Regrowth appeared between 10 and 24 h and reached a high population level (1.25 x 10(8) cfu ml-1) after 7 d. Monolaurin (250 micrograms ml-1) had a bacteriostatic effect during the first 10 h but thereafter, regrowth occurred slowly with a population level after 7 d (4 x 10(5) cfu ml-1) lower than that of nisin. Different combined effects of nisin (between 0 and 42 IU ml-1), monolaurin (ranging from 0 to 300 micrograms ml-1), pH values (between 5.0 and 7.0) and spore loads (10(3), 10(4), 10(5) spores ml-1) were investigated using a Doehlert matrix in order to study the main effects of these factors and the different interactions. Results were analysed using the Response Surface Methodology (RSM) and indicated that nisin and monolaurin had no action on spores before germination; only pH values had a significant effect (P < or = 0.001), i.e. spore count decreased as the pH value increased in relation to germination. Sublethal concentrations of nisin (30 IU ml-1) and monolaurin (100 micrograms ml-1) in combination acted synergistically on outgrown spores and vegetative cells, showing total inhibition at pH 6.0, without regrowth, within 7 d at 37 degrees C.

Animals↗
PubMed2003

Variable-angle total internal reflection fluorescence microscopy (VA-TIRFM): realization and application of a compact illumination device.

A novel compact illumination device in variable-angle total internal reflection fluorescence microscopy (VA-TIRFM) is described. This device replaces the standard condensor of an upright microscope. Light from different laser sources is delivered via a monomode fibre and focused onto identical parts of a sample under variable angles of total internal reflection. Thus, fluorophores in close proximity to a cell-substrate interface are excited by an evanescent wave with variable penetration depth, and localized with high (nanometre) axial resolution. In addition to quantitative measurements in solution, fluorescence markers of the cytoplasm and the plasma membrane, i.e. calcein and laurdan, were examined using cultivated endothelial cells. Distances between the glass substrate and the plasma membrane were determined using the mathematical algorithm of a four-layer model, as well as a Gaussian-shaped intensity profile of the illumination spot on the samples. Distances between 0 and 30 nm in focal contacts and between 100 and 300 nm in other parts of the cell were thus determined. In addition to measurements of cell-substrate topology, the illumination device appears appropriate for numerous applications in which high axial resolution is required, e.g. experiments on endocytosis or exocytosis, as well as measurements of ion concentrations proximal to the plasma membrane. The compact illumination device is also suitable for combining TIRFM with further innovative techniques, e.g. time-resolved fluorescence spectroscopy, fluorescence lifetime imaging (FLIM) or fluorescence resonance energy transfer (FRET).

2-Naphthylamine↗
PubMed2003

Time-gated total internal reflection fluorescence spectroscopy (TG-TIRFS): application to the membrane marker laurdan.

A novel setup for total internal reflection fluorescence microscopy with spectral and temporal (nanosecond) resolution was used to measure the emission spectra of the membrane marker laurdan either selectively within the plasma membrane or in whole living cells, depending on the incident angle of the excitation light. With increasing temperature, the intensity of the fluorescence band around 490 nm increased in comparison with the band around 440 nm, which has previously been assigned to a phase transition of membrane lipids from gel to liquid crystalline phase. For a better separation of the overlapping spectral bands, time-gated detection with a delay of 10-15 ns with respect to the exciting laser pulse was used. As a parameter of membrane dynamics the so-called generalized polarization GP = (I440 - I490)/(I440 + I490) was evaluated at temperatures between 24 and 41 degrees C and variable angles of the incident light permitting to excite laurdan molecules either within the plasma membrane or in the whole cell. A decrease of the GP values by approximately 0.2 units between 28 and 41 degrees C indicated an increase in membrane fluidity or a decrease in membrane stiffness with increasing temperature. In addition, higher GP values were observed for the plasma membrane as compared with intracellular membranes, probably due to a higher amount of cholesterol. Because properties of the plasma membrane have a large influence on the uptake or release of certain pharmaceutical agents or metabolites, the direct assessment of the dynamics of the plasma membrane by total internal reflection fluorescence spectroscopy appears to be important for pharmacology.

2-Naphthylamine↗
PubMed2000

Effect of experimental diabetes on the fatty acid composition, molecular species of phosphatidyl-choline and physical properties of hepatic microsomal membranes.

Streptozotocin diabetes depresses delta 9, delta 6 and delta 5 fatty acid desaturases, decreasing arachidonic acid and increasing linoleic acid, but also unexpectedly increasing docosahexaenoic acid in the different phospholipids of liver microsomal lipids. 18:0/20:4n-6, 16:0/20:4n-6 and 16:0/18:2n-6 are the predominant phosphatidyl choline (PC) molecular species in control rats, determining mainly PC contribution to the dynamic and biochemical properties of this bilayer. Diabetes decreases 20:4n-6 containing species and increases 18:2n-6 and 22:6n-3 containing species, maintaining the bulk dynamic properties in the hydrophobic interior of the bilayer, but changing its biochemical properties. The different dynamic parameters were measured by fluorometry using the probes 1,6-diphenyl-1,3,5-hexatriene (DPH), (4-trimethylammonium phenyl) 6-phenyl-1,3,5 (TMA-DPH) and 6-lauroyl-2,4-dimethyl aminonaphtalene (Laurdan). In the surrounding of the hydrophobic/hydrophilic interphase lipid molecules were less ordered and tightly packed in the diabetic samples, allowing a higher mobility of incorporated water molecules. The fact that diabetes decreases highly polyunsaturated acid of n-6 family, but increases docosahexaenoic acid, indicates the necessity of re-evaluating its effect in human physiology.

2-Naphthylamine↗
PubMed1991

Incorporation of 12-methoxydodecanoate into the human immunodeficiency virus 1 gag polyprotein precursor inhibits its proteolytic processing and virus production in a chronically infected human lymphoid cell line.

Covalent linkage of myristate (tetradecanoate; 14:0) to the NH2-terminal glycine residue of the human immunodeficiency virus 1 (HIV-1) 55-kDa gag polyprotein precursor (Pr55gag) is necessary for its proteolytic processing and viral assembly. We have shown recently that several analogs of myristate in which a methylene group is replaced by a single oxygen or sulfur atom are substrates for Saccharomyces cerevisiae and mammalian myristoyl-CoA:protein N-myristoyltransferase (EC 2.3.1.97; NMT) despite their reduced hydrophobicity. Some inhibit HIV-1 replication in acutely infected CD4+H9 cells without accompanying cellular toxicity. To examine the mechanism of their antiviral effects, we performed labeling studies with two analogs, 12-methoxydodecanoate (13-oxamyristate; 13-OxaMyr) and 5-octyloxypentanoate (6-oxamyristate; 6-OxaMyr), the former being much more effective than the latter in blocking virus production. [3H]Myristate and [3H]13-OxaMyr were incorporated into Pr55gag with comparable efficiency when it was coexpressed with S. cerevisiae NMT in Escherichia coli. [3H]6-OxaMyr was not incorporated, even though its substrate properties in vitro were similar to those of 13-OxaMyr and myristate. [3H]13-OxaMyr, but not [3H]6-OxaMyr, was also efficiently incorporated into HIV-1 Pr55gag and nef (negative factor) in chronically infected H9 cells. Analog incorporation produced a redistribution of Pr55gag from membrane to cytosolic fractions and markedly decreased its proteolytic processing by viral protease. 13-OxaMyr and 3'-azido-3'-deoxythymidine (AZT) act synergistically to reduce virus production in acutely infected H9 cells. Unlike AZT, the analog is able to inhibit virus production (up to 70%) in chronically infected H9 cells. Moreover, the inhibitory effect lasts 6-8 days. These results suggest that (i) its mechanism of action is distinct from that of AZT and involves a late step in virus assembly; (ii) the analog may allow reduction in the dose of AZT required to affect viral replication; and (iii) combinations of analog and HIV-1 protease inhibitors may have synergistic effects on the processing of Pr55gag.

Antiviral Agents↗
PubMed2000

Thermogenic responses in brown fat cells are fully UCP1-dependent. UCP2 or UCP3 do not substitute for UCP1 in adrenergically or fatty scid-induced thermogenesis.

To examine the thermogenic significance of the classical uncoupling protein-1 (UCP1), the thermogenic potential of brown adipocytes isolated from UCP1-ablated mice was investigated. Ucp1(-/-) cells had a basal metabolic rate identical to wild-type; the mitochondria within them were coupled to the same degree. The response to norepinephrine in wild-type cells was robust ( approximately 10-fold increase in thermogenesis); Ucp1(-/-) cells only responded approximately 3% of this. Ucp1(-/-) cells were as potent as wild-type in norepinephrine-induced cAMP accumulation and lipolysis and had a similar mitochondrial respiratory complement. In wild-type cells, fatty acids induced a thermogenic response similar to norepinephrine, but fatty acids (and retinoate) were practically without effect in Ucp1(-/-) cells. It is concluded that no other adrenergically induced thermogenic mechanism exists in brown adipocytes except that mediated by UCP1 and that entopic expression of UCP1 does not lead to overt innate uncoupling, and it is suggested that fatty acids are transformed to an intracellular physiological activator of UCP1. High expression of UCP2 and UCP3 in the tissue was not associated with an overt innate highly uncoupled state of mitochondria within the cells, nor with an ability of norepinephrine or endo- or exogenous fatty acids to induce uncoupled respiration in the cells. Thus, UCP1 remains the only physiologically potent thermogenic uncoupling protein in these cells.

Adipocytes↗
PubMed2001

Unique effects of different fatty acid species on the physical properties of the torpedo acetylcholine receptor membrane.

To study the effects produced by free fatty acids (FFA) on the biophysical properties of Torpedo marmorata nicotinic acetylcholine receptor-rich native membranes and to investigate the topology of their binding site(s), fluorescence measurements were carried out using the fluorescent probe Laurdan (6-dodecanoyl-2-(dimethylamino) naphthalene) and ADIFAB, an Acrylodan-derivatized intestinal fatty acid-binding protein. The generalized polarization (GP) of the former probe was used to learn about the physical state of the membrane upon FFA binding. Saturated FFA induced a slight increase in GP, whereas cis-unsaturated fatty acids decreased GP. Double bond isomerism could also be distinguished; oleic acid (18:1cis) induced a net disordering effect, whereas elaidic acid (18:1trans) produced no changes in GP. The changes in the efficiency of the Förster energy transfer from the protein to Laurdan brought about by addition of FFA, together with the distances involved in this process, indicate that all FFA studied share a common site at the lipid-protein interface. However, despite being located at the same site, each class of FFA differs in its effect on the physical properties of the membrane. These data lead us to suggest that it is the direct action of FFA at the lipid-protein interface, displacing essential lipids from their sites rather than changes in bulk properties such as membrane fluidity that accounts for the effect of FFA on the acetylcholine receptor membrane.

2-Naphthylamine↗
PubMed2003

The association of alpha-synuclein with membranes affects bilayer structure, stability, and fibril formation.

The aggregation of alpha-synuclein is believed to be a critical factor in the etiology of Parkinson's disease. alpha-Synuclein is an abundant neuronal protein of unknown function, which is enriched in the presynaptic terminals of neurons. Although alpha-synuclein is found predominantly in the cytosolic fractions, membrane-bound alpha-synuclein has been suggested to play an important role in fibril formation. The effects of alpha-synuclein on lipid bilayers of different compositions were determined using fluorescent environment-specific probes located at various depths. alpha-Synuclein-membrane interactions were found to affect both protein and membrane properties. Our results indicate that in addition to electrostatic interactions, hydrophobic interactions are important in the association of the protein with the bilayer, and lead to disruption of the membrane. The latter was observed by atomic force microscopy and fluorescent dye leakage from vesicles. The kinetics of alpha-synuclein fibril formation were significantly affected by the protein association and subsequent membrane disruption, and reflected the conformation of alpha-synuclein. The ability of alpha-synuclein to disrupt membranes correlated with the binding affinity of alpha-synuclein for the particular membrane composition, and to the induced helical conformation of alpha-synuclein. Protofibrillar or fibrillar alpha-synuclein caused a much more rapid destruction of the membrane than soluble monomeric alpha-synuclein, indicating that protofibrils (oligomers) or fibrils are likely to be significantly neurotoxic.

2-Naphthylamine↗
PubMed2003

A substrate-induced switch in the reaction mechanism of a thermophilic esterase: kinetic evidences and structural basis.

The reaction mechanism of the esterase 2 (EST2) from Alicyclobacillus acidocaldarius was studied at the kinetic and structural level to shed light on the mechanism of activity and substrate specificity increase previously observed in its double mutant M211S/R215L. In particular, the values of kinetic constants (k1, k(-1), k2, and k3) along with activation energies (E1, E(-1), E2, and E3) were measured for wild type and mutant enzyme. The previously suggested substrate-induced switch in the reaction mechanism from kcat=k3 with a short acyl chain substrate (p-nitrophenyl hexanoate) to kcat=k2 with a long acyl chain substrate (p-nitrophenyl dodecanoate) was validated. The inhibition afforded by an irreversible inhibitor (1-hexadecanesulfonyl chloride), structurally related to p-nitrophenyl dodecanoate, was studied by kinetic analysis. Moreover the three-dimensional structure of the double mutant bound to this inhibitor was determined, providing essential information on the enzyme mechanism. In fact, structural analysis explained the observed substrate-induced switch because of an inversion in the binding mode of the long acyl chain derivatives with respect to the acyl- and alcohol-binding sites.

Alcohols↗
PubMed2005

Ceramide 1-phosphate, a mediator of phagocytosis.

The agonist-stimulated metabolism of membrane lipids produces potent second messengers that regulate phagocytosis. We studied whether human ceramide kinase (hCERK) activity and ceramide 1-phosphate formation could lead to enhanced phagocytosis through a mechanism involving modulation of the membrane-structural order parameter. hCERK was stably transfected into COS-1 cells that were stably transfected with the FcgammaRIIA receptor. hCERK-transfected cells displayed a significant increase in phagocytic index in association with increased ceramide kinase activation and translocation to lipid rafts after activation with opsonized erythrocytes. When challenged with opsonized erythrocytes, hCERK-transfected cells increased phagocytosis by 1.5-fold compared with vector control and simultaneously increased ceramide 1-phosphate levels 2-fold compared with vector and unstimulated control cells. Control and hCERK-transfected cells were subjected to cellular fractionation. Utilizing an antibody against hCERK, we observed that CERK translocates during activation from the cytosol to a lipid raft fraction. The plasma membrane-structural order parameter of the transfectants was measured by labeling cells with Laurdan. Cells transfected with hCERK showed a higher liquid crystalline order than control cells with stimulation, conditions that are favorable for the promotion of membrane fusion at the sites of phagocytosis. The change in the structural order parameter of the lipid rafts probably contributes to phagocytosis by promoting phagosome formation.

2-Naphthylamine↗
PubMedDate not supplied

Lipid matters: nicotinic acetylcholine receptor-lipid interactions (Review).

Ligand-gated ion channels mediate fast intercellular communication in response to endogenous neurotransmitters. The nicotinic acetylcholine receptor (AChR) is the archetype molecule in the superfamily of these membrane proteins. Early electron spin resonance studies led to the discovery of a lipid fraction in direct contact with the AChR, with rotational dynamics 50-fold slower than those of the bulk lipids. This AChR-vicinal lipid region has since been postulated to be a possible site of lipid modulation of receptor function. The polarity and molecular dynamics of solvent dipoles-mainly water-of AChR-vicinal lipids in the membrane have been studied with Laurdan extrinsic fluorescence, and Forster-type resonance energy transfer (FRET) was introduced to characterize the receptor-associated lipid microenvironment. FRET enabled one to discriminate between the bulk lipid and the AChR-vicinal lipid. The latter is in a liquid-ordered phase and exhibits a higher degree of order than the bulk bilayer lipid. Changes in FRET efficiency induced by fatty acids, phospholipids and cholesterol also led to the identification of discrete sites for these lipids on the AChR protein. After delineating the topography of the AChR membrane-embedded domains with fluorescence methods, sites for steroids are being explored with site-directed mutagenesis and patch-clamp recording. Pyrene-labelled Cys residues in alphaM1, alphaM4, gammaM1 and gammaM4 transmembrane regions were found to lie in a shallow position. For M4 segments, this is in agreement with a canonical linear alpha-helix; for M1, it is necessary to postulate a substantial amount of non-helical structure, and/or of kinks, to rationalize the shallow location of Cys residues. Mutations of Thr422, a residue close to the extracellular-facing membrane hemilayer in alphaM4, affect the steroid modulation of AChR function, suggesting its involvement in steroid-AChR interactions.

2-Naphthylamine↗
PubMedDate not supplied

Visualizing membrane microdomains by Laurdan 2-photon microscopy.

Lateral segregation of cell membrane components gives rise to microdomains with a different structure within the membrane. Most prominently, lipid rafts are defined as domains in liquid ordered phase whereas surrounding membranes are more fluid. Here we review a 2-photon fluorescence microscopy approach, which allows the visualization of membrane fluidity. The fluorescent probe Laurdan exhibits a blue shift in emission with increasing membrane condensation caused by an alteration in the dipole moment of the probe as a consequence of exclusion of water molecules from the lipid bilayer. The quantification of membrane order is achieved by the Generalized Polarization (GP) values, which are defined as normalized intensity ratios of two emission channels. GP images are therefore not biased by probe concentrations and membrane ruffles. Furthermore, Laurdan reports membrane structure independently from the lipid and protein cargo of the membrane domains. We give examples where Laurdan microscopy was instrumental in quantifying the formation of condensed membrane domains and their cellular requirements. Moreover we discuss how microdomains identified by Laurdan microscopy are consistent with domains identified by other methodologies and put GP images in the context of current raft hypotheses.

2-Naphthylamine↗
PubMed2004

Sulfhydryl based cationic surfactants and the impact of polyanions on disulfide bond formation: implications for gene transfer vectors.

Compacting plasmid DNA (pDNA) into a small size is a fundamental necessity for the efficient in vivo transfer of nucleic acids to somatic cells. An approach for accomplishing this is to condense pDNA using cationic detergents with sulfhydryl groups, near their critical micelle concentration. In this study, a model surfactant was used to study how the rate of disulfide bond formation relates to environmental factors. It was shown that the thiol detergent had the ability to form a disulfide bond when oxidized and the presence of polyanions was significantly increased. The addition of a reducing agent disrupted the disulfide bonds initially, but this was followed by disulfide bond reformation in a short time period.

Cations↗
PubMed1994

The effect of glycerol monolaurate on growth of, and production of toxic shock syndrome toxin-1 and lipase by, Staphylococcus aureus.

The effects of glycerol monolaurate on the growth of, and production of Toxic Shock Syndrome Toxin-1 (TSST-1) and lipase by, Staphylococcus aureus FRI 1187 were investigated in batch and continuous culture models using a defined synthetic medium. The growth and yield of S. aureus depended on glycerol monolaurate concentration, pH of the environment and the inoculum size. The MICs for glycerol monolaurate of 29 S. aureus isolates, determined in a complex medium, were between 10 and 20 mg/L with a 10(3) to 10(4) cfu inoculum; a 1000-fold increase in inoculum size increased the MIC five-fold. In continuous culture, glycerol monolaurate increased the cell yield of S. aureus. In batch cultures with 17 mg/L glycerol monolaurate, TSST-1 and lipase production by S. aureus was delayed and their specific production was not decreased compared with cultures without glycerol monolaurate. At 150 mg/L glycerol monolaurate, growth and toxin production were decreased. The lipase of S. aureus hydrolyzed glycerol monolaurate. The reduction of toxin production was associated with effects on S. aureus growth, and these effects might have been relieved after lipase had been produced.

Bacterial Toxins↗
PubMed1975

Dietary effects of the esters of butyric, caproic, caprylic, capric, lauric, myristic, palmitic, and stearic acids on food intake, weight gain, plasma glucose, and tissue lipid in the male white rat.

Eight saturated fatty acid esters were fed to male white rats for 30 days in a 1/81 fractional factorial experiment in which diets contained 12-38% of their total energy as lipid. Marked increases in food intake, feed efficiency, and weight gain were achieved when lipid provided 36% of diet energy, and when that lipid was more than half caproate, caprate, myristate, and/or stearate. Caproate was the only saturated fatty acid to increase plasma glucose levels. The feeding of stearate or caprylate decreased plasma and liver cholesterol. Caprate increased liver fat. The short-chain fatty acids (butyrate to myristate) increased the concentration of fat in the carcass.

Animal Nutritional Physiological Phenomena↗