Association between dexamethasone treatment and alterations in serum concentrations of trace metals.

Previously, a significant elevation in the serum levels of iron (Fe) was observed within a few days after the initiation of cisplatin (CDDP)-based chemotherapy. To clarify the underlying mechanisms, the serum concentration of hepcidin, a negative regulator of Fe release, was determined in the clinical samples obtained from six patients with cancer. The result showed that the serum concentration of hepcidin in patients receiving CDDP-based chemotherapy was significantly increased after 4-6 days of treatment, in comparison to the baseline level, suggesting that aforementioned excessive systemic Fe was not explained by the change of serum hepcidin level. All these patients received antiemetic premedication. We next evaluated of the effects of Pt-containing drugs and prophylactic antiemetic dexamethasone medication on the serum concentration of trace metals in mice, and on the hepatic and renal concentration of trace metals. The serum concentrations of Fe, Cu, and Zn in the CDDP-treated and oxaliplatin-treated mice were not significantly altered in comparison to those of the vehicle-treated control group. The serum concentrations of Fe, Cu, and Zn were increased after 24 h of dexamethasone treatment, compared to those of the control group (P < 0.05). The hepatic concentration of Mn was significantly reduced, whereas those of Fe and Cu inclined to diminish. The present findings suggest that dexamethasone can partly contribute to the changes in the serum concentrations of trace metals during anticancer chemotherapy.

Potentially inappropriate medications in elderly Japanese patients: effects of pharmacists' assessment and intervention based on Screening Tool of Older Persons' Potentially Inappropriate Prescriptions criteria ver.2.

WHAT IS KNOWN AND OBJECTIVES: The Screening Tool of Older Persons' Potentially Inappropriate Prescriptions (stopp) criteria were updated in 2014 (stopp criteria ver.2), but few studies have evaluated the usefulness of stopp criteria in elderly patients. This prospective observational study evaluated the prevalence of potentially inappropriate medications (PIMs), and the efficacy of hospital pharmacists' assessment and intervention based on stopp criteria ver.2. METHODS: The study was conducted at three medical units of Kobe University Hospital between April 2015 and March 2016. Pharmacists assessed and detected PIMs based on stopp criteria ver.2 and considered the patient's intention to change the prescription at the time of admission of each patient. If the pharmacists judged that benefits outweighed risks of prescription change and the patients consented to change the medications, they recommended the doctor to change the prescription. If there was a risk of exacerbation of disease by the change of medications and the pharmacists judged it to be difficult to adjust medications during hospitalization or the patients did not consent to change the medications, they did not recommend to change it. The pharmacists and the doctors discussed and finally decided whether to change the PIMs or not. The number of patients prescribed PIMs, the number and contents of PIMs, and the number of medications changed after pharmacists' intervention were calculated. RESULTS: Totally, 822 new inpatients aged ≥65 years prescribed ≥1 daily medicine were included. Their median (interquartile range) age was 75·0 (71·0-80·0) years, and 54·9% were male. According to the criteria, 346 patients (42·1%) were prescribed ≥1 PIMs. Patients prescribed PIMs took significantly more medications than others: 10·0 (7·0-13·0) vs. 6·0 (4·0-9·0), P < 0·001. The total number of PIMs was 651%, 47·6% of which (n = 310) were recommended the doctors to change, and 292 of 651 PIMs (44·9%) were finally discontinued/changed after pharmacists' assessment and intervention. PIMs related to benzodiazepines, including Z-drugs, were most frequent, with a detailed classifications as follows (changed/total): (i) benzodiazepines for 4 or more weeks (75/205), (ii) drugs that predictably increase the risk of falls in older people (benzodiazepines) (30/67) and (iii) drugs that predictably increase the risk of falls in older people (hypnotic Z-drugs) (15/31). CONCLUSION: Over 40% elderly patients were prescribed PIMs, and pharmacists' assessments and interventions based on stopp criteria ver.2 were useful in detecting and correcting prescription of PIMs.

Efficacy of protocol-based pharmacotherapy management on anticoagulation with warfarin for patients with cardiovascular surgery.

WHAT IS KNOWN AND OBJECTIVE: Anticoagulation therapy with warfarin requires periodic monitoring of prothrombin time-international normalized ratio (PT-INR) and adequate dose adjustments based on the data to minimize the risk of bleeding and thromboembolic events. In our hospital, we have developed protocol-based pharmaceutical care, which we called protocol-based pharmacotherapy management (PBPM), for warfarin therapy. The protocol requires pharmacists to manage timing of blood sampling for measuring PT-INR and warfarin dosage determination based on an algorithm. This study evaluated the efficacy of PBPM in warfarin therapy by comparing to conventional pharmaceutical care. METHODS: From October 2013 to June 2015, a total of 134 hospitalized patients who underwent cardiovascular surgeries received post-operative warfarin therapy. The early series of patients received warfarin therapy as the conventional care (control group, n=77), whereas the latter received warfarin therapy based on the PBPM (PBPM group, n=68). These patients formed the cohort of the present study and were retrospectively analysed. RESULTS: The indications for warfarin included aortic valve replacement (n=56), mitral valve replacement (n=4), mitral valve plasty (n=22) and atrial fibrillation (n=29). There were no differences in patients' characteristics between both groups. The percentage time in therapeutic range in the first 10 days was significantly higher in the PBPM group (47.1%) than that in the control group (34.4%, P<.005). The average time to reach the steady state was significantly (P<.005) shorter in the PBPM group compared to the control group (7.3 vs 8.6 days). WHAT IS NEW AND CONCLUSION: Warfarin therapy based on our novel PBPM was clinically safe and resulted in significantly better anticoagulation control compared to conventional care.

Degree of freezing does not affect efficacy of frozen gloves for prevention of docetaxel-induced nail toxicity in breast cancer patients.

PURPOSE: Frozen gloves (FG) are effective in preventing docetaxel-induced nail toxicity (DNT), but uncomfortable. The preventive effect of FG for DNT was compared using a standard (-25 to -30°C) or more comfortable (-10 to -20°C) preparation. METHODS: Breast cancer patients receiving docetaxel were eligible. Each patient wore an FG (prepared at -10 to -20°C for 90 min) for 60 min without replacement on the right hand. The left hand was protected by standard methods (FG prepared at -25 to -30°C overnight and worn for 90 min with replacement at 45 min). The primary endpoint was DNT occurrence at 5 months. Secondary endpoints included docetaxel exposure [cumulative dose and area under the blood concentration time curve (AUC)] until DNT occurrence and discomfort from FG. The pharmacokinetics of docetaxel was assessed. RESULTS: From 23 patients enrolled between December 2006 and June 2010, seven who received docetaxel for less than 5 months were excluded from evaluation. The median accumulated docetaxel dose was 700 mg/m(2) (340-1430 mg/m(2)). Within 5 months of FG use, none developed protocol-defined DNT in either hand. Two patients (13%) developed DNT at 7.2 and 7.3 months, respectively, both at -10 to -20°C. In the control hand (-25 to -30°C), discomfort occurred in 92% of the cycles, compared to 15% in the experimental hand (-10 to -20°C). Five patients (22%) experienced pain at -25 to -30°C, but none did at -10 to -20°C. The degree of docetaxel exposure was not related to DNT occurrence in our study. CONCLUSION: A convenient preparation of FG at -10 to -20°C is almost as effective as a standard preparation at -25 to -30°C, with significantly less discomfort.

Population pharmacokinetics and pharmacodynamics of mycophenolic acid using the prospective data in patients undergoing hematopoietic stem cell transplantation.

Mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA), is used to suppress GvHD in patients undergoing hematopoietic stem cell transplantation (HCT). The purpose of this study was to construct a population pharmacokinetic and pharmacodynamic model in HCT patients for individualized MPA therapy. Blood samples were obtained from 49 HCT patients after starting MMF therapy. Population pharmacokinetic and pharmacodynamic parameters were obtained using the program NONMEM. MPA was described via a one-compartment model with a first-order elimination, and 30.9% of MPA glucuronide (MPAG) was found in the enterohepatic circulation. Inosine-5'-monophosphate dehydrogenase (IMPDH) activity was modeled as a maximal inhibitory model with a half-maximal inhibitory concentration (IC50) of 3.59 µg/mL against MPA concentrations. Simulations based on the obtained pharmacokinetic and pharmacodynamic parameters revealed that decreased creatinine clearance increases the MPAG concentration followed by an increased MPA concentration; therefore, IMPDH activity decreases. Diarrhea decreases the enterohepatic circulation of MPAG and consequently reduces MPA concentration. The IC50 for MPA exhibited a positive association with C-reactive protein. Dosage adjustment based on plasma MPA concentration is required especially for patients with renal dysfunction and/or diarrhea.

Anti-tuberculosis drug susceptibility testing of Mycobacterium bovis BCG Tokyo strain.

SETTING: The Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccine is the only vaccine against tuberculosis (TB), owing to its valuable protective effects and low virulence. However, it can occasionally cause systemic infection in immunocompromised hosts. Isoniazid (INH), rifampicin (RMP), streptomycin (SM) and ethambutol (EMB) are known to be effective anti-tuberculosis drugs and are used for the treatment of BCG infections. Unfortunately, there are few studies of the susceptibility of BCG vaccine strains to these drugs. OBJECTIVE: To measure the minimum inhibitory concentrations (MICs) of BCG Tokyo vaccine products for anti-tuberculosis drugs and assess vaccine safety in terms of drug susceptibility. DESIGN: We measured the MIC for one seed and five product lots of BCG Tokyo strain for INH, RMP, SM and EMB using Middlebrook 7H11 agar plates. RESULTS: The MIC results for INH were 0.06 and 0.125 mg/ml for the product and seed lots, respectively. The MIC results for RMP, SM and EMB were 0.25-0.5, 0.25 and 2-4 microg/ml, respectively. CONCLUSION: Our results indicate that the BCG Tokyo strain was susceptible to the major anti-tuberculosis drugs and treatable even in cases of severe adverse events, including systemic infection.

Lipids and fatty acids of a moderately halophilic bacterium, No. 101.

The extractable and bound lipids of a moderately halophilic gram-negative rod, strain No. 101 (wild type) grown in a medium containing 2 M NaC1, were examined. The extractable lipids were separated into at least 8 components by using thin-layer chromatography. The major phospholipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an unidentified phosphoglycolipid in the whole cells, cell envelopes and outer membrane preparations, commonly. Judging from mild alkaline hydrolysis and exzymatic treatment with phospholipase A2, C and D, the unidentified phosphoglycolipid possessing Pi, glycerol, fatty acids and glucose in a molar ratio of 1 : 2 : 2 : 1, appeared likely to be a glucosyl derivative of phosphatidylglycerol. No glucuronic acid containing lipid was detected. The exractable lipid composition varied greatly with the concentrations of NaC1 in the medium and the stages of bacterial growth. The most characteristic phosphoglycolipid in this organism increased up to 25% of the total phospholipids with the addition of 1% glucose in the medium. The major fatty acids of the extractable lipids were C16:0, C16:1, C18:0, C18:1 and cyclopropanoic C17 and C19 acids and these compositions were very similar for each phospholipid. The cyclopropanoic fatty acids predominated as growth proceeded. The fatty acids of the bound lipids comprised a high concentration of 3-hydroxydodecanoic acid. The esterified fatty acids of the lipopolysaccharide molecule seemed to contain a wide variety of hydroxy and non-hydroxy shorter chain fatty acids, while the amide-linked fatty acids consisted almost entirely of 3-hydroxydodecanoic acid.

Inhibitory effect of KW-3902, an adenosine A(1) receptor antagonist, on p-aminohippurate transport in OK cells.

KW-3902 (8-(noradamantan-3-yl)-1,3-dipropylxanthine) is a novel potent and selective adenosine A(1) receptor antagonist. We examined the effect of KW-3902 on p-aminohippurate (PAH) transport in opossum kidney (OK) epithelial cells. Pretreatment for 3 h with KW-3902 inhibited the transcellular transport of PAH across OK cell monolayers from the basal to the apical side. The uptake of PAH across the basolateral membrane of OK cells was inhibited by KW-3902 pretreatment in a time- and concentration-dependent manner. A kinetic analysis revealed that the inhibitory effect of KW-3902 on the basolateral PAH uptake was due to an increase in the Michaelis constant (K(m)) as well as a decrease in the maximum uptake rate (V(max)), showing that the inhibition was a mixed type. Pretreatment with adenosine deaminase or 8-cyclopentyl-1,3-dipropylxanthine, another selective adenosine A(1) receptor antagonist, also decreased the basolateral PAH uptake. KW-3902 pretreatment had no effect on the concentration of intracellular alpha-ketoglutarate which exchanges for PAH across the basolateral membrane of OK cells. These results suggest that KW-3902 has an inhibitory effect on PAH transport in OK epithelial cells.

Effect of clarithromycin on renal excretion of digoxin: interaction with P-glycoprotein.

We present a digoxin-clarithromycin interaction in two patients in whom digoxin concentrations were unexpectedly increased. The ratio of renal digoxin clearance to creatinine clearance in one patient was lower during the concomitant administration of clarithromycin (0.64 and 0.73) than that after cessation of clarithromycin administration (1.30 +/- 0.20; mean +/- SD). Because P-glycoprotein could play an important role in the renal secretion of digoxin, we hypothesized that clarithromycin decreases renal digoxin excretion by inhibiting P-glycoprotein-mediated transport. Digoxin transport was evaluated with use of a kidney epithelial cell line, which expresses the human P-glycoprotein on the apical membrane by transfection with MDR1 complementary deoxyribonucleic acid. Clarithromycin inhibited the transcellular transport of digoxin from the basolateral to the apical side in a concentration-dependent manner and concomitantly increased the cellular accumulation of digoxin. These results suggest that clarithromycin may inhibit the P-glycoprotein-mediated tubular secretion of digoxin, and this interaction mechanism may contribute to an increase in the serum digoxin concentration.

Direct involvement of hydrogen peroxide in bacterial alpha-hydroxylation of fatty acid.

We have reported that fatty-acid alpha-hydroxylase partially purified from Sphingomonas paucimobilis required NADH and molecular oxygen. In this study, we found that the reaction was greatly inhibited by catalase. Glutathione and glutathione peroxidase also inhibited alpha-hydroxylation, but superoxide dismutase and mannitol did not. Replacement of NADH and molecular oxygen by hydrogen peroxide increased the alpha-hydroxylation activity. In the presence of hydrogen peroxide, molecular oxygen was not required for the activity. These findings suggest that hydrogen peroxide was essential for bacterial alpha-hydroxylase.

Mycobacterial cord factor, but not sulfolipid, causes depletion of NKT cells and upregulation of CD1d1 on murine macrophages.

Trehalose 6,6'-dimycolate (TDM, cord factor) has frequently been used as an adjuvant to stimulate antibody production. Although it also induces cellular immunity, detailed studies about the underlying events do not exist. To determine the kinetics of TDM-specific changes promoting a T helper 1 (Th1) response, we injected mice with TDM or 2,3,6,6'-tetraacyl trehalose 2'-sulfate (SL, sulfolipid), another mycobacterial trehalose-containing glycolipid without mycolic acid. TDM, but not SL, caused a strong increase in serum interferon-gamma (IFN-gamma) levels 2 days later, accompanied by expansion of natural killer (NK) cells. Subsequent TDM effects included depletion of normal-density CD4(+) NK1.1(+) TCRalpha/beta(intermediate) cells from day 7 on, upregulation of MHC class II and CD1d1 on macrophages (peaking on day 21), and an increased proportion of Th1 cells evident after 3 weeks. TDM, but not a similar glycolipid without mycolic acid, can therefore initiate a cascade of events starting with strong release of IFN-gamma and NK cell expansion, resulting in the appearance of macrophages activated for antigen presentation. Our data therefore provide the basis for optimized immunization schedules with TDM as the adjuvant component of a Th1 vaccine.

Incorporation of [14C]glucose from UDP[14C]glucose into a phosphoglycolipid by cell-free particulate systems of a moderately halophilic gram-negative bacterium, Pseudomonas halosaccharolytica ATCC 29423.

A glucosyl group from uridine diphosphate [U-14C]glucose is incorporated into a phosphoglycolipid, probably a glucosylphosphatidylglycerol, by a disrupted membrane enzyme preparation from a gram-negative, moderately halophilic bacterium, Pseudomonas halosaccharolytica ATCC 29423. The conversion of [14C]phosphatidylglycerol into phosphoglycolipid by the particulate preparation was also enhanced in the presence of non-labelled UDP-glucose. A chemical degradation study of labelled phosphoglycolipid showed the bulk of the radioactivity from UDP[U-14C]glucose to be associated with the glucose moiety, which also appeared to be attached to the hydroxyl group of a second glycerol.

Relationship between induction of macrophage chemotactic factors and formation of granulomas caused by mycoloyl glycolipids from Rhodococcus ruber (Nocardia rubra).

Mycoloyl glycolipids cause granulomas in the lungs, liver, and spleen of mice, but the mechanism is not fully understood. To understand the role of macrophage chemotactic factors (MCFs) in granuloma formation, we prepared various mycoloyl glycolipids with different carbohydrate moieties: trehalose dimycolate (TDM), glucose mycolate (GM), mannose mycolate (MM), and fructose mycolate (FM) from Rhodococcus ruber, and examined the relationship between their MCF induction in peritoneal macrophages and the extent of granuloma formation. The molecular mass of each glycolipid was confirmed by fast-atom-bombardment mass-spectrometry. TDM or GM caused granulomas in the lungs, spleen, and liver of ICR mice, but MM and FM did not. The culture supernatant of peritoneal macrophages stimulated with TDM or GM increased macrophage migration, whereas MM and FM had no chemotactic activity. The activity of interleukin-1 (IL-1) in the supernatant was increased equally by each glycolipid and was therefore not related to chemotaxis. Tumor necrosis factor-alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were not detected in the four supernatants. The TDM-induced MCF was heat-stable, trypsin-labile, and undialyzable. Furthermore, we separated two MCF active fractions from the supernatant of TDM-stimulated macrophages by gel filtration. These factors acted on macrophages but not on neutrophils. Our results suggested that macrophages recognize the sugar moieties of mycoloyl glycolipids and may, in response, generate a MCF that may play an important role in the macrophage or monocyte recruitment which is essential prior to granuloma formation.

Occurrence of free ceramides in Bacteroides fragilis NCTC 9343.

The occurrence of free ceramides at high concentrations was demonstrated in the chloroform-methanol extractable lipids of Bacteroides fragilis NCTC 9343. The long-chain bases were isolated from the free ceramides and identified as branched and normal saturated dihydroxy bases with carbon chains consisting of 17, 18, and 19 atoms. The major fatty acid was 3-hydroxy 15-methylhexadecanoic acid. The major molecular species of the ceramides were identified by gas chromatography-mass spectrometry and gas chromatography of the cleaved products as LCB-d-iso17: 0-3-OH iso17: 0 FA, LCB-d-anteiso17: 0-3-OH iso17: 0 FA, LCB-d-iso18: 0-3-OH iso17: 0 FA, and LCB-d-anteiso19: 0-3-OH iso17: 0 FA.

Isolation of a novel sphingoglycolipid containing glucuronic acid and 2-hydroxy fatty acid from Flavobacterium devorans ATCC 10829.

A new acidic sphingoglycolipid has been isolated from a Gram-negative, glucose-non-fermentative (obligatory aerobic) bacterium, Flavobacterium devorans ATCC 10829, by thin-layer chromatography on silica gel after mild alkaline hydrolysis of the cellular lipids. Chemical degradation studies, thin-layer chromatographic behavior, IR and mass-spectrometric analysis of the original and reduced glycolipid with LiA1H4 revealed that the lipid contained glucuronic acid, long-chain bases, and fatty acids in a molar ratio of approximately 1:1:1. The major long-chain bases were identified by gas chromatography-mass spectrometry as dihydrosphingosine (d-18 :0) and longer homologues, while the N-acyl group was exclusively 2-hydroxy myristic acid. The most probable structure of this glycolipid appeared to be a ceramide glucuronic acid (N-acyl dihydrosphingosine 1-glucuronic acid).

Stimulation of phagocytosis and phagosome-lysosome fusion by glycosphingolipids from Sphingomonas paucimobilis.

Sphingomonas paucimobilis, a Gram-negative opportunistic pathogen, is actively phagocytosed by human peripheral polymorphonuclear leukocytes (PMN) in vitro. However, when live or killed cells were delipidated, the phagocytic rate was clearly decreased. Therefore, we have investigated the physiological role of membrane lipids in phagocytic processes. S. paucimobilis type strain 2395 produces four classes of acidic glycosphingolipids (GL-1, GL-2, GL-3, and GL-4) with the common components of glucuronic acid, 2-hydroxy myristic acid and d18:0 or d21:1 long-chain base. The effect of acidic glycosphingolipids on phagocytosis by PMN using killed Staphylococcus aureus cells coated with glucuronosyl ceramide (GL-1) or ceramide tetrahexoside (GL-4) was also examined. The rate of phagosome-lysosome fusion by PMN was determined by counting acridine orange-stained bacteria under a fluorescence microscope. Both phagocytosis and phagosome-lysosome fusion by PMN of glycosphingolipid-coated bacteria were stimulated markedly in a dose-dependent manner. It was noted that GL-1 or GL-4 stimulated phagosome-lysosome fusion dramatically, but synthetic lipid A did not. Superoxide anion release from PMN was enhanced significantly by the coating with synthetic lipid A at higher concentration, but only slightly with GL-1 or GL-4. Glucuronic acid was an inhibitor of phagocytosis of GL-1-coated S. aureus by PMN. The effect of acidic glycosphingolipids obtained from mammalian tissue on phagocytosis was also compared with that of bacterial glycosphingolipids. Ganglioside GM3 and sulfatide showed a marked stimulative activity for phagocytosis by PMN, while the neutral glycosphingolipids did not. Thus, bacterial acidic glycosphingolipid and mammalian acidic glycosphingolipid promote phagocytosis and phagosome-lysosome fusion by PMN.

ESR studies on the membrane properties of a moderately halophilic bacterium. I. Physical properties of lipid bilayers in whole cells.

The lipid membrane properties of a moderately halophilic gram-negative bacterium, Pseudomonas halosaccharolytica ATCC 29423, were studied by the use of stearate spin labels, 5NS, 12NS, and 16NS, changing the temperature of ESR measurement from 15 to 50 degrees C. The order parameter and the rotational correlation time of the spin labels incorporated into intact cell membranes of this bacterium grown at various temperatures in media containing different NaCl concentrations were calculated. The activation energy of rotational microviscosity was obtained from Andrade plots. At low growth temperature and low NaCl concentration in the medium, extractable lipids of this bacterium contained comparatively large amounts of unsaturated fatty acids, but as the growth temperature and NaCl concentration in the medium increased, the contents of saturated and cyclopropanoic fatty acids increased to more than half of the total fatty acids. 5NS gave the highest order parameters for the intact cells of this bacterium, while 12NS gave lower and 16NS gave the lowest results. The order parameters of 5NS, 12NS, and 16NS were completely separated, and all order parameters decreased gradually as the measuring temperature was increased. In contrast, the rotational correlation times of the intact cells with 12NS were as large as those with 5NS, while those with 16NS were distinctly smaller. Increasing NaCl concentrations in the growth medium caused an increase of the rotational correlation times, that is, stiffened the lipid bilayers. The Andrade plot for 16NS was approximately a straight line, whereas 5NS and 12NS gave two straight lines crossing at a temperature near the growth temperature, indicating phase transition from solid to liquid. The microviscosity activation energies were 5--10 kcal/mol in the liquid phase and 15--25 kcal/mol in the solid phase.

ESR studies on the membrane properties of a moderately halophilic bacterium. II. Effect of extreme growth conditions on liposome properties.

Lipid preparations from the cells of a moderately halophilic bacterium, Pseudomonas halosaccharolytica grown under the two extreme conditions of high temperature-high NaCl concentration and low temperature-low NaCl concentration showed distinctively different profiles in phospholipid and fatty acid composition. Cells grown at 40 degrees C in medium containing 3.5 M NaCl had high concentrations of saturated and C19 cyclopropanoic fatty acids (about 50 per cent of the total), whereas cells grown at 20 degrees C in medium containing 0.5 M NaCl had decreased concentrations of these fatty acids with increased concentrations of the corresponding unsaturated fatty acids. The phospholipid composition was also affected ty the culture conditions; cells grown at 40 degrees C in 3.5 M NaCl had large amounts of acidic phospholipids, whereas those grown at 20 degrees C in 0.5 M NaCl had small amounts. ESR studies on liposomes prepared from lipids of cells grown under the two conditions showed characteristic profiles for correlation times and order parameters of three spin labels of stearic acid derivatives similar to those of membranes of whole cells of this bacterium. ESR studies showed that the physical properties of the liposomes from the total extractable lipids and isolated phosphatidylglycerol from the cells were completely different from those of synthetic dioleoylphosphatidylglycerol. Liposomes of the lipids extracted from cells grown at 40 degrees C in 3.5 M NaCl showed change in rotational viscosity on altering the NaCl concentration to 0.5M, whereas liposomes of lipids extracted from cells grown at 20 degrees C in 0.5 M NaCl did not show change in rotational viscosity on increasing the NaCl concentration to 3.5 M.

Thermally adaptive changes of mycolic acids in Mycobacterium smegmatis.

The effect of growth temperature on mycolic acid composition in eight strains of Mycobacterium smegmatis was investigated by gas chromatography/mass spectrometry. A change in growth temperature from 45 to 20 degrees C caused a shift in the subclass and molecular species composition of mycolic acids. The relative amount of alpha'-mycolic acids to alpha-mycolic acids decreased, and that of hydroxy mycolic acids increased at lower temperatures. Moreover, the proportion of shorter-chain species of alpha-mycolic acids increased, and those of longer-chain species of alpha-mycolic and hydroxy mycolic acids decreased. This observation seems to be due to the changes of the chain length of meromycolates because the alpha-alkyl chain unit of mycolic acids was not affected. The ratio of odd to even carbon-numbered alpha-mycolates decreased as the growth temperature was lowered. In contrast, the molecular species composition of alpha'-mycolic acid was not influenced by the growth temperature.

Regulation of cell wall mycolic acid biosynthesis in acid-fast bacteria. I. Temperature-induced changes in mycolic acid molecular species and related compounds in Mycobacterium phlei.

Molecular species of two major subclasses of mycolic acids from Mycobacterium phlei, alpha-mycolic acids (M1) and dicarboxy mycolic acids (M3), were separated gas-chromatographically and identified mass-spectrometrically. The mycolic acid compositions of extractable and cell wall bound lipids were markedly influenced by growth temperature. Increasing growth temperature from 20 degrees C to 50 degrees C resulted in an increase in longer chain species of both mycolisc acid subclasses with a concomitant decrease in shorter chain homologues. The most abundant molecular species were C76 and C58 of M1 and M3 in the 20 degrees C grown cells, while the 50 degrees C grown cells contained C80 in M1 and C62 in M3, most abundantly. Changes in mycolic acid composition occurred rapidly after growth temperature was raised from 20 degrees C to 50 degrees C with an increase in C62 and a concomitant decrease in C58. Mass fragmentographic analysis revealed that an increase in total carbon numbers of mycolic acids was caused by the elongation of straight chain alkyl unit, without any changes in alpha-branch. Changes in the molecular species composition of secondary alcohols presumably derived from the ester mycolic acids were also observed and an increase in longer species (C20-ol-2) with a concomitant decrease in shorter ones (C18-ol-2) was noted as the temperature rose. An increase in the growth temperature also resulted in a decrease in unsaturated fatty acids in extractable lipids. These observations suggest that mycobacteria alter the molecular species composition of mycolic acid subclasses and phospholipids, in response to growth temperature, to maintain a suitable membrane function.