Mycobacterium tuberculosis Rv1916 is an Acetyl-CoA-Binding Protein

Isocitrate lyase (ICL) isoform 2 is an essential enzyme for some clinical Mycobacterium tuberculosis (Mtb) strains during infection. In the laboratory Mtb strain H37Rv, the icl2 gene encodes two distinct gene products – Rv1915 and Rv1916 – due to a frameshift mutation. This study aims to characterise these two gene products to understand their structure and function. While we were unable to produce Rv1915 recombinantly, soluble Rv1916 was obtained with sufficient yield for characterisation. Kinetic studies using UV-visible spectrophotometry and ¹H-NMR spectroscopy showed that recombinant Rv1916 does not possess isocitrate lyase activity, while waterLOGSY binding experiments demonstrated that it could bind acetyl-CoA. Finally, X-ray crystallography revealed structural similarities between Rv1916 and the C-terminal domain of ICL2. Considering the probable differences between full-length ICL2 and the gene products Rv1915 and Rv1916, care must be taken when using Mtb H37Rv as a model organism to study central carbon metabolism.     

Efficient intraliposomal entrapment of hydrophilic platinum oligonuclear complexes

A simple method for intraliposomal entrapment of platinum complexes is presented, where hydrophilic platinum oligonuclear complexes, 1-methyluracil green (MeUG), uridine green (UdG) and uridine blue (UdB), are included inside liposomes and allowed to react with bilayer lipids. The liposomes prepared in this method exhibit higher entrapment efficiency and higher distribution to organs (liver, kidney, spleen, lung) and blood (but not B16 cancer cells) than those prepared from mononuclear Pt complexes [cis-diamminedichloroplatinum, cis-diammine-1,1′-dicarboxylatocyclobutaneplatinum, and cis-dichloro-cis-dihydroxy-trans-bis(isopropylamine)platinum)].     

Efficient intraliposomal entrapment of hydrophilic platinum oligonuclear complexes

A simple method for intraliposomal entrapment of platinum complexes is presented, where hydrophilic platinum oligonuclear complexes, 1-methyluracil green (MeUG), uridine green (UdG) and uridine blue (UdB), are included inside liposomes and allowed to react with bilayer lipids. The liposomes prepared in this method exhibit higher entrapment efficiency and higher distribution to organs (liver, kidney, spleen, lung) and blood (but not B16 cancer cells) than those prepared from mononuclear Pt complexes [cis-diamminedichloroplatinum, cis-diammine-1,1′-dicarboxylatocyclobutaneplatinum, and cis-dichloro-cis-dihydroxy-trans-bis(isopropylamine)platinum)].     

Thermal, optical, electrochemical properties and conductivity of trans- and cis-poly(1-ethynylpyrene): a comparative investigation

The thermal, optical and electrochemical properties of trans-poly(1-ethynylpyrene) (trans-PEP) and cis-poly(1-ethynylpyrene) (cis-PEP) have been studied as a function of polymer backbone configuration and internal stacking. Absorption spectra of the polymers showed that trans-PEP possesses a higher degree of conjugation than its homologue, cis-PEP. Intramolecular interactions occur between adjacent pendant pyrene units (associated pyrenes) present in each polymer, giving rise to static excimer emissions, strongest in cis-PEP because of the shorter distances between aromatic rings. Data resulting from excitation spectra and fluorescence decay profiles proved that such interactions take place in the ground state. Cyclic voltammetry of trans- and cis-PEP exhibited irreversible behaviors with different oxidation potentials as a result of their dissimilar geometry.     

Biomimetic Thiyl Radical Chemistry by γ-Irradiation of Micelles and Vesicles Containing Unsaturated Fatty Acids

Different types of lipid aggregations, such as micelles and liposomes, can be used as biomimetic models. The uses of γ-irradiation as a valid methodology for simulating the biological generation of thiyl radicals in these models are summarized and, in particular, thiyl radical catalyzed cis trans isomerization of unsaturated lipids is underlined. The efficiency of antioxidants against lipid isomerization assayed by biomimetic models and the importance of trans lipids as novel biomarkers of radical stress are also described.     

Linear and nonlinear optical properties of trans- and cis-poly(1-ethynylpyrene) based sonogel hybrid materials

The synthesis of sol-gel materials induced by ultrasonic action (sonolysis) is implemented as an alternative method for the fabrication of highly pure organic-inorganic composites with good monolithic and optical properties. The resulting SiO₂ glass exhibits high porosity and allows the inclusion of organic compounds in the colloidal sol-state. In this work, optical properties of trans-poly(1-ethynylpyrene) (trans-PEP) and cis-poly(1-ethynylpyrene) (cis-PEP) (M_w=24,000 g/mol) incorporated in this kind of gels were studied by absorption and fluorescence spectroscopies. Absorption spectra of the polymers showed that trans-PEP possesses a higher degree of conjugation than its homologue cis-PEP in sol-gel. Intramolecular interactions occur between adjacent pendant pyrene units (associated pyrenes) present in each polymer, giving rise to static excimer emissions, strongest in cis-PEP because of the shorter distances between aromatic rings. The results were compared to those previously reported for these polymers in solution. Besides, trans- and cis-PEP exhibited nonlinear optical properties like third harmonic generation (THG), which were measured in sol-gel phase for spin-coated film samples.     

Distributions of hydroperoxide positional isomers generated by oxidation of 1-palmitoyl-2-arachidonoyl-<Emphasis Type="Italic">sn</Emphasis>-glycero-3-phosphocholine in liposomes and in methanol solution

The differences in distribution of geometric isomers of unsaturated PC hydroperoxides generated by free radical oxidation were compared, as corresponding hydroxy analogs, in heterogeneous liposomes and in a homogeneous methanol solution by using HPLC with UV detection due to the presence of conjugated dienes. Identification of fractionated peak components was carried out by GC-MS. When the oxidation of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine, PC(16∶0/18∶2), was initiated in liposomes by a hydrophilic azo radical initiator, and in a methanol solution by a hydrophobic azo radical initiator, there was no significant difference in the relative percentages of 1-palmitoyl-2-(9-hydroxy-trans-10,trans-12-octadecadienoyl)-sn-glycero-3-phosphocholine (9-t,t-OH PC) and 1-palmitoyl-2-(13-hydroxy-trans-9,trans-11-octadecadienoyl)-sn-glycero-3-phosphocholine (13-t,t-OH PC) between the PC oxidized in liposomes and in the methanol solution. For the oxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, PC(16∶0/20∶4), the relative percentage of 1-palmitoyl-2-(5-hydroxy-trans-6,cis-8,11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (5-OH PC) was significantly higher (P<0.01) than that of 1-palmitoyl-2-(15-hydroxy-cis-5,8,11,trans-13-eicosatetraenoyl)-sn-glycero-3-phosphocholine (15-OH PC) in liposomes. For the homogeneous methanol solution of PC(16∶0/20∶4), the relative percentage of 5-OH PC was close to that of 15-OH PC. For the PC(16∶0/20∶4) oxidized in bulk with added pentamethylchromanol, the individual amount of 15-OH PC, 1-palmitoyl-2-(11-hydroxy-cis-5,8trans-12,cis-14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (11-OH PC), 1-palmitoyl-2-(12-hydroxy-cis-5,8,trans-10,cis-14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (12-OH PC), 1-palmitoyl-2-(8-hydroxy-cis-5,trans-9,cis-11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (8-OH PC), 1-palmitoyl-2-(9-hydroxy-cis-5,trans-7,cis-11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (9-OH PC), and 5-OH PC were close to each other compared to the corresponding values in liposomes and in methanol solution. The results obtained by gel permeation chromatography of the PC liposomes containing hydrophilic 2,2′-azobis-2-amidinopropane) dihydrochloride (AAPH) suggest that the AAPH added to the liposomes of PC(16∶0/20∶4) was partitioned into the water phase and out of the hydrophobic region of the fatty acyl moieties of the PC. These results confirm that the distance that exists in the bis-allylic carbons of the unsaturated fatty acyl moieties of PC from the interface between the hydrophilic region of PC and the water phases played an important role in influencing hydrogen abstraction to form a symmetrical distribution of hydroperoxide isomers in both the heterogeneous liposomes and the homogeneous methanol solution.     

Prostaglandins of rat testis

The purpose of the study was to determine whether prostaglandins were present in mammalian testis, a tissue that has a large concentration of polyenoic fatty acids that are potential precursors of prostaglandins. Acid-soluble lipids of rat testis were extracted, purified, and fractionated by thin layer and column chromatographies.³H-Prostaglandins were added as internal reference standards to monitor recoveries and facilitate identification. Initial identification of prostaglandin species was done by chromatography. Further identification was done by elution of the prostaglandin zones followed by rechromatographies (both thin layer and column), measurements of UV absorption spectra, and by gas liquid chromatography. The results of these analyses indicate that prostaglandin E₁, 11α,15(S)-dihydroxy-9-oxo-β-trans-prostenoic acid; prostaglandin E₂, 11α-15(S)-dihydroxy-9-oxo-5-cis-13-trans-prostadienoic acid; and prostaglandin F₁, 9α,11α,15(S)-trihydroxy-13-trans-prostenoic acid occur in rat testicular tissue and that prostaglandin F_2α, 9α, 11α, 15(S)-trihydroxy-5-cis-13-trans-prostadienoic acid and prostaglandin E₂, 11α,15(S)-dihydroxy-9-oxo-5-cis-13-trans-prostadienoic acid may be the primary species of this tissue. Prostaglandin B₁, 15(S)-hydroxy-9-oxo-8(12),13-trans-prostadienoic acid and prostaglandin B₂, 15(S)-hydroxy-9-oxo-5-cis,8(12),13-trans-prostatrienoic acid also were detected, and some evidence was obtained for the presence of prostaglandin metabolites.     

Development of Potent Inhibitors of the Mycobacterium tuberculosis Virulence Factor Zmp1 and Evaluation of Their Effect on Mycobacterial Survival inside Macrophages

The enzyme Zmp1 is a zinc‐containing peptidase that plays a critical role in the pathogenicity of Mycobacterium tuberculosis. Herein we describe the identification of a small set of Zmp1 inhibitors based on a novel 8‐hydroxyquinoline‐2‐hydroxamate scaffold. Among the synthesized compounds, N‐(benzyloxy)‐8‐hydroxyquinoline‐2‐carboxamide ( 1 c ) was found to be the most potent Zmp1 inhibitor known to date, and its binding mode was analyzed both by kinetics studies and molecular modeling, identifying critical interactions of 1 c with the zinc ion and residues in the active site. The effect of 1 c on intracellular Mycobacterium survival was assayed in J774 murine macrophages infected with M. tuberculosis H37Rv or M. bovis BCG and human monocyte‐derived macrophages infected with M. tuberculosis H37Rv. Cytotoxicity and genotoxicity were also assessed. Overall, inhibitor 1 c displays interesting in vitro antitubercular properties worthy of further investigation.     

Effect of CLA on the cellular lipids of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

The yeast Saccharomyces cerevisiae was cultivated in the presence of free CLA that was either a pure trans-10, cis-12 isomer, a pure cis-9, trans-11 isomer, or a 1∶1 mixture of the two, and the influence of these supplementations on the content and FA composition of the lipids in the yeast was determined. Neither the pure isomers nor their 1∶1 mixture influenced the growth of the yeast, but the trans-10, cis-12 isomer reduced the amount of cellular lipids by 40%. The reduction in total cellular lipids by the trans-10, cis-12 CLA was due to a reduction in TAG. Both of the isomers were incorporated into the yeast lipids, reaching a proportion of about 33% in TAG. With the incorporation of CLA, the yeast reduced the amount and desaturation of endogenously synthesized FA. These clear and pronounced isomer-specific effects of CLA on the yeast suggest that yeast might be a useful model to obtain a more comprehensive view of the mechanisms of the action of CLA on lipid metabolism.     

Conformational Insights into the Control of CNF1 Toxin Activity by Peptidyl-Prolyl Isomerization: A Molecular Dynamics Perspective

The cytotoxic necrotizing factor 1 (CNF1) toxin from uropathogenic Escherichia coli constitutively activates Rho GTPases by catalyzing the deamidation of a critical glutamine residue located in the switch II (SWII). In crystallographic structures of the CNF1 catalytic domain (CNF1^CD), surface-exposed P768 and P968 peptidyl-prolyl imide bonds (X-Pro) adopt an unusual cis conformation. Here, we show that mutation of each proline residue into glycine abrogates CNF1^CD in vitro deamidase activity, while mutant forms of CNF1 remain functional on RhoA in cells. Using molecular dynamics simulations coupled to protein-peptide docking, we highlight the long-distance impact of peptidyl-prolyl cis-trans isomerization on the network of interactions between the loops bordering the entrance of the catalytic cleft. The energetically favorable isomerization of P768 compared with P968, induces an enlargement of loop L1 that fosters the invasion of CNF1^CD catalytic cleft by a peptide encompassing SWII of RhoA. The connection of the P968 cis isomer to the catalytic cysteine C866 via a ladder of stacking interactions is alleviated along the cis-trans isomerization. Finally, the cis-trans conversion of P768 favors a switch of the thiol side chain of C866 from a resting to an active orientation. The long-distance impact of peptidyl-prolyl cis-trans isomerizations is expected to have implications for target modification.     

Photo-oxidation of lipids impregnated on the surface of dried seaweed (<Emphasis Type="Italic">Porphyra yezoensis</Emphasis> Ueda). Hydroperoxide distribution

The distribution of hydroperoxide isomers generated by photo-oxidation of natural lipids impregnated on the surface of dried seaweed previously exposed to visible light and without added photosensitizer were studied. The surface of dried seaweed was impregnated with linoleic acid methyl ester, and the sample was divided into two parts. One part was exposed to light from a 100-W tungsten bulb (4500 lux) in a low-temperature room (5°C). The other part was kept in the dark as a control. Positional isomers of the hydroperoxides generated from the impregnated linoleic acid methyl ester were separated individually by HPLC and further identified by MS. The dried seaweed kept in the dark contained four hydroperoxide isomers, namely, 13-hydroperoxy-cis-9, trans-11-octadecadienoate, 13-hydroperoxy-trans-9, trans-11-octadecadienoate, 9-hydroperoxy-trans-10,cis-12-octadecadienoate, and 9-hydroperoxy-trans-10, trans-12-octadecadienoate. For the dried seaweed exposed to light, the oxidized lipids contained not only the same four isomers, but also 12-hydroperoxy-cis-9, trans-13-octadecadienoate and 10-hydroperoxy-trans-8,cis-12-octadecadienoate. When fresh seaweed was dried in the sunlight, the formation of 12-cis,trans- and 10-cis,trans-hydroperoxides of naturally occurring methyl linoleate was verified. Dried seaweed was then impregnated with eicosapentaenoic acid ethyl ester and exposed to light. Light exposure also generated certain hydroperoxide isomers attributable to singlet oxygen oxidation, namely, 6-hydroperoxy-trans-4,cis-8, cis-11,cis-14,cis-17-ethyl and 17-hydroperoxy-cis-5,cis-8,cis-11, cis-14,trans-18-ethyl eicosapentaenoate. When dried sea-weed without any impregnated lipids was exposed to the light for 24 h in a cold room (5°C), characteristic isomers, including both the 20-carbon FA isomers 6-OOH and 17-OOH as well as the 18-carbon FA isomers 10-OOH and 12-OOH, were detected in the light-exposed sample but were not found in the control. These results clearly show that singlet oxygen oxidation of lipids occurred in the seaweed exposed to light. We concluded that this lipid oxidation was catalyzed by chlorophyll as a photosensitizer in seaweed.     

Production of the criegee ozonide during the ozonation of 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes

It is likely that Criegee ozonides are formed in small amounts in the lungs of animals breathing ozone-containing air. This makes these compounds potential candidates to act as secondary toxins which relay the toxic effects of ozone deeper into lung tissue than ozone itself could penetrate. Therefore, we have determined the yields of Criegee ozonides from unsaturated lipids in liposomal systems as a model of the types of yields of Criegee ozonides that might be expected both in the lung lining fluid layer and in biological membranes. Ozonation of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes produced bothcis- andtrans-Criegee ozonides. These ozonides have been isolated by solid phase extraction and high-performance liquid chromatography of the ozonized lipid, and the products have been identified by two-dimensional¹H nuclear magnetic resonance. The combined yield of thecis- andtrans-Criegee ozonides is 10.7±2.8% (avg. ±SD, n=7) with small unilamellar liposomes and 10.6±2.7% (n=3) with large multilamellar liposomes. We had previously reported (Chem. Res. Toxicol. 5 505–511, 1992) that ozonation of methyl oleate in sodium dodecylsulfate micelles also produces an 11% yield of the Criegee ozonides. Thus, ozonation in a variety of models gives about 11% of the Criegee ozonide, suggesting that these products also would be formed in small but significant amounts in the lungs of animals breathing polluted air. Further research on the pharmacokinetics and possible toxicity of the Criegee ozonides of fatty acids is suggested.     

Distributions of conjugated linoleic acid (CLA) isomers in tissue lipid classes of pigs fed a commercial CLA mixture determined by gas chromatography and silver ion-high-performance liquid chromatography

Pigs were fed a commercial conjugated linoleic acid (CLA) mixture, prepared by alkali isomerization of sunflower oil, at 2% of the basal diet, from 61.5 to 106 kg live weight, and were compared to pigs fed the same basal diet with 2% added sunflower oil. The total lipids from liver, heart, inner back fat, and omental fat of pigs fed the CLA diet were analyzed for the incorporation of CLA isomers into all the tissue lipid classes. A total of 10 lipid classes were isolated by three-directional thin-layer chromatography and analyzed by gas chromatography (GC) on long capillary columns and by silver-ion high-performance liquid chromatography (Ag⁺-HPLC); cholesterol was determined spectrophotometrically. Only trace amounts (<0.1%; by GC) of the 9,11–18∶2 cis/trans and trans, trans isomers were observed in pigs fed the control diet. Ten and twelve CLA isomers in the diet and in pig tissue lipids were sepatated by GC and Ag⁺-HPLC, respectively. The relative concentration of all the CLA isomers in the different lipid classes ranged from 1 to 6% of the total fatty acids. The four major cis/trans isomers (18.9% 11 cis, 13 trans-18∶2; 26.3% 10 trans, 12 cis-18∶2; 20.4% 9 cis, 11 trans-18∶2; and 16.1% 8 trans, 10 cis-18∶2) constituted 82% of the total CLA isomers in the dietary CLA mixture, and smaller amounts of the corresponding cis,cis (7.4%) and trans,trans (10.1%) isomers were present. The distribution of CLA isomers in inner back fat and in omental fat of the pigs was similar to that found in the diet. The liver triacylglycerols (TAG), free fatty acids (FFA), and cholesteryl esters showed a similar patterns to that found in the diet. The major liver phospholipids showed a marked increase of 9 cis,11 trans-18∶2, ranging from 36 to 54%, compared to that present in the diet. However, liver diphosphatidylglycerol (DPG) showed a high incorporation of the 11 cis,13 trans-18∶2 isomer (43%). All heart lipid classes, except TAG, showed a high content of 11 cis,13 trans-18∶2, which was in marked contrast to results in the liver. The relative proportion of 11 cis,13 trans-18∶2 ranged from 30% in the FFA to 77% in DPG. The second major isomer in all heart lipids was 9 cis,11 trans-18∶2. In both liver and heart lipids the relative proportions of both 10 trans,12 cis-18∶2 and 8 trans,10 cis-18∶2 were significantly lower compared to that found in the diet. The FFA in liver and heart showed the highest content of trans,trans isomers (31 to 36%) among all the lipid classes. The preferential accumulation of the 11 cis,13 trans-18∶2 into cardiac lipids, and in particular the major phospholipid in the inner mitochondrial membrane, DPG, in both heart and liver, appears unique and may be of concern. The levels of 11 cis,13 trans-18∶2 naturally found in foods have not been established.     

Preliminary Evaluation of Artemisinin–Cholesterol Conjugates as Potential Drugs for the Treatment of Intractable Forms of Malaria and Tuberculosis

To evaluate the feasibility of developing drugs that may be active against both malaria and tuberculosis (TB) by using in part putative cholesterol transporters in the causative pathogens and through enhancement of passive diffusion in granulomatous TB, artemisinin–cholesterol conjugates were synthesized by connecting the component molecules through various linkers. The compounds were screened in vitro against Plasmodium falciparum (Pf) and Mycobacterium tuberculosis (Mtb). Antimalarial activities (IC₅₀) against Pf drug‐sensitive NF54, and drug‐resistant K1 and W2 strains ranged from 0.03–2.6, 0.03–1.9, and 0.02–1.7 μm . Although the compounds are less active than the precursor artemisinin derivatives, the cholesterol moiety renders the compounds relatively insoluble in the culture medium, and variation in solubilities among the different compounds may reflect in the range of efficacies observed. Activities against Mtb H37Rv were assessed using a standardized colony‐forming unit (CFU) assay after 24 h pretreatment of cultures with each of the compounds. Percentage inhibition ranged from 3–38 % and 18–52 % at 10 and 80 μm , respectively. Thus, in contrast to the comparator drug artemether, the conjugates display enhanced activities. The immediate aims include the preparation of conjugates with enhanced aqueous solubilities, assays against malaria and TB in vivo, and for TB, assays using an infected macrophage model and assessment of granuloma influx.     

Trans-10,Cis-12 conjugated linoleic acid reduces triglyceride content while differentially affecting peroxisome proliferator activated receptor γ2 and aP2 expression in 3T3-L1 preadipocytes

A series of experiments was conducted using 3T3-L1 preadipocytes as the cell model to determine: (i) whether the triglyceride (TG)-lowering effects of a crude mixture of conjugated linoleic acid (CLA) isomers were due to a specific isomer of CLA and the timing of treatment, (ii) if CLA reduced TG content by inhibiting a key regulator of adipogenesis, (iii) if CLA incorporated into either neutral lipid or phospholipid cell fractions, and (iv) whether the effects of CLA treatment were reversible. Trans-10,cis-12 CLA reduced TG content, whereas the cis-9,trans-11 isomer increased TG content compared to vehicle [bovine serum albumin (BSA)] controls. Treatment with 50 μM trans-10,cis-12 CLA during the entire 6 d of differentiation reduced TG content to a greater extent than treatment during either the first 3 d or last 3 d of differentiation. Trans-10,cis-12 CLA treatment of preadipocyte cultures for 48 h increased peroxisome proliferator activated receptor γ2 (PPARγ2) protein expression compared to cultures treated with linoleic acid (LA) or the BSA controls. CLA had no effect on adipose P2 (aP2), a fatty acid-binding protein regulated by PPARγ2. Both the cis-9,trans-11 and the trans-10,cis-12 isomers of CLA were incorporated into neutral lipids and phospholipids. However, cis-9,trans-11 CLA levels were one- to twofold higher than trans-10,cis-12 CLA levels. Moreover, trans-10,cis-12 CLA treatment reduced cis-11 18∶1 concentrations in both neutral lipids and phospholipids while increasing cis-9 18∶1 and 18∶2 concentrations. Palmitoleic acid (16∶1) levels were also lower in the neutral lipid fraction of cultures treated with trans-10,cis-12 CLA. Supplementing trans-10,cis-12 CLA-treated cultures (50 μM) with increasing levels of LA resulted in a dose-dependent increase in TG content compared to cultures treated with 50 μM CLA alone. LA supplementation also prevented some of the morphological changes associated with trans-10,cis-12 CLA treatment as seen with scanning electron microscopy. Treatment with 50μM trans-10,cis-12 CLA for 6 d decreased PPARγ2 levels, and supplementation of CLA-treated cultures with LA increased PPARγ2 levels compared with cultures treated with CLA alone. Taken together, these data indicate that in cultures of 3T3-L1 preadipocytes: (i) trans-10,cis-12 CLA is the TG-lowering isomer of CLA, and its effects are dependent on dose, duration of treatment, and the amount of LA in the cultures; (ii) trans-10,cis-12 CLA treatment alters the monounsaturated fatty acid profile of neutral- and phospholipids of the cultures; and (iii) although acute (2−d) trans-10,cis-12 CLA treatment increased PPARγ2 protein levels, chronic (6−d) treatment decreased PPARγ2 levels.     

Interconversion of verbenols and verbenone by identified yeasts isolated from the spruce bark beetleIps typographus

Six yeast strains have been isolated and identified from the spruce bark beetle,Ips typographus. We have studied the ability of the yeasts to interconvertcis-verbenol,trans-verbenol, and verbenone. (1S)-cis-Verbenol is an active component in the aggregation pheromone ofIps typographus. The isolatedCandida molischiana/ Hansenula capsulata strain can convert both (1R)- and (1S)-cis-verbenol to verbenone. TheCandida nitratophila strain converts (1R)-cis-verbenol totrans-verbenol and (1S)-cis-verbenol to verbenone. Some of the yeast strains produce 3-methylbutanol, 2-methylpropanol, and 2-phenylethanol after growth in Sabouraud medium.     

On the existence of cis/trans peptide mixtures in poly(N-methylglycine)

Unperturbed dimensions have been computed for poly(trans-N-methylglycine), poly(cis-N-methylglycine) and poly(cis/trans-N-methylglycine) by a Monte Carlo simulation technique using potential energy calculations. Computed characteristic ratios for the above polypeptides vary within a narrow range supporting the view that both cis and trans units could be present in the polymer in different proportions under different solvent conditions.