High Performance Chromatographic and Spectroscopic Analyses of Mycobacterial Waxes and Glycolipids

1990 ◽  
pp. 137-148 ◽  
Author(s):  
David E. Minnikin ◽  
Gary Dobson ◽  
Robert C. Bolton ◽  
James H. Parlett ◽  
Anthony I. Mallet
2020 ◽  
Vol 75 (3-4) ◽  
pp. 75-86
Author(s):  
Taiji Nomura ◽  
Yasuo Kato

AbstractTuliposides (Pos) are major defensive secondary metabolites in tulip (genus Tulipa), having 4-hydroxy-2-methylenebutanoyl and/or (3S)-3,4-dihydroxy-2-methylenebutanoyl groups at the C-1 and/or C-6 positions of d-glucose. The acyl group at the C-6 position is converted to antimicrobial lactones, tulipalins, by tuliposide-converting enzymes (TCEs). In the course of a survey of tulip tissue extracts to identify novel Pos, we found a minute high-performance liquid chromatography peak that disappeared following the action of a TCE, and whose retention time differed from those of known Pos. Spectroscopic analyses of the purified compound, as well as its enzymatic degradation products, revealed its structure as 5″-O-(6-O-(4′-hydroxy-2′-methylenebutanoyl))-β-d-glucopyranosyl-(2″R)-2″-hydroxymethyl-4″-butyrolactone, which is a novel glucoside ester-type Pos. We gave this compound the trivial name ‘tuliposide G’ (PosG). PosG accumulated in bulbs, at markedly lower levels than 6-PosA (the major Pos in bulbs), but was not found in any other tissues. Quantification of PosG in bulbs of 52 types of tulip, including 30 cultivars (Tulipa gesneriana) and 22 wild Tulipa spp., resulted in the detection of PosG in 28 cultivars, while PosG was present only in three wild species belonging to the subgenus Tulipa, the same subgenus to which tulip cultivars belong, suggesting the potential usefulness of PosG as a chemotaxonomic marker in tulip.


2020 ◽  
Vol 75 (1-2) ◽  
pp. 7-12 ◽  
Author(s):  
Taiji Nomura ◽  
Shinjiro Ogita ◽  
Yasuo Kato

Abstract6-Tuliposides A (6-PosA) and B (6-PosB) are major defensive secondary metabolites in tulip cultivars (Tulipa gesneriana), having an acyl group at the C-6 position of d-glucose. Although some wild tulip species produce 1,6-diacyl-glucose type of Pos (PosD and PosF), as well as 6-PosA/B, they have not yet been isolated from tulip cultivars. Here, aiming at verifying the presence of PosD and PosF in tulip cultivars, tissue extracts of 25 cultivars were analyzed by high-performance liquid chromatography (HPLC). Although no HPLC peaks for PosD nor PosF were detected in most cultivars, we found two cultivars giving a minute HPLC peak for PosD and the other two cultivars giving that for PosF. PosD and PosF were then purified from petals of cultivar ‘Orca’ and from pistils of cultivar ‘Murasakizuisho’, respectively, and their identities were verified by spectroscopic analyses. This is the first report that substantiates the presence of 1,6-diacyl-glucose type of Pos in tulip cultivars.


Antioxidants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 539 ◽  
Author(s):  
Hyoung-Geun Kim ◽  
Young Sung Jung ◽  
Seon Min Oh ◽  
Hyun-Ji Oh ◽  
Jung-Hwan Ko ◽  
...  

(1) Background: Many flavonoids derived from natural sources have been reported to exhibit antioxidant and anti-inflammatory effects. Our preliminary study suggested that Coreopsis lanceolata flowers (CLFs) include high flavonoid content; (2) Methods: CLFs were extracted in 80% (v/v) aqueous methanol and fractionated into ethyl acetate, n-butanol, and water fractions. Repeated column chromatographies for the organic fractions led to the isolation of seven flavanones. Quantitative analysis of the flavanones was carried out using reversed-phase high-performance liquid chromatography. All flavanones were evaluated for their antioxidant and pro-inflammatory inhibition effects; (3) Results: Spectroscopic analyses revealed the chemical structure of five new flavanones, coreolanceolins A–E, and two known ones. The content of the seven flavanones in extracts were determined from 0.8 ± 0.1 to 38.8 ± 0.3 mg/g. All flavanones showed radical scavenging activities (respectively 104.3 ± 1.9 to 20.5 ± 0.3 mg vitamin C equivalents (VCE)/100 mg and 1278.6 ± 26.8 to 325.6 ± 0.2 mg VCE/100 mg) in the DPPH and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays and recovery activities in Caco-2 (59.7 to 41.1%), RAW264.7 (87.8 to 56.0%), and PC-12 (100.5 to 69.9%) cells against reactive oxygen species. Furthermore, all flavanones suppressed nitric oxide production (99.5% to 37.3%) and reduced iNOS and COX-2 expression in lipopolysaccharide-treated RAW 264.7 cells; (4) Conclusions: Five new and two known flavanones were isolated from CLF, and most of them showed high antioxidant and pro-inflammatory inhibition effects.


2018 ◽  
Vol 91 (4) ◽  
pp. 729-750 ◽  
Author(s):  
Tuhin Saha ◽  
Anil K. Bhowmick ◽  
Takeshi Oda ◽  
Toshiaki Miyauchi ◽  
Nobuhiko Fujii

ABSTRACT To develop high-performance polyacrylicester (ACM) elastomeric components with higher scorch safety and superior thermal and mechanical properties, we replaced aliphatic diamine curatives with aromatic dianiline curatives. The influence of dianiline curatives 4,4′-(4,4′-isopropylidenediphenyl-1,1′-diyldioxy)dianiline, 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline, and 4,4′-(1,1′-biphenyl-4,4′-diyldioxy)dianiline on the network structures and thermal, dynamic mechanical, and mechanical properties of ACM vulcanizates was investigated. The kinetics of vulcanization was analyzed for different dianiline curatives, with the use of rheometer curves. To understand the electronic properties and study the relation between chemical structure and reactivity, density functional theory was used. The time–temperature superposition principal was used to evaluate the activation energy for degradation of cross-linked samples. Finally, the curing mechanism of ACM in the presence of dianiline curative was studied with X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. These spectroscopic analyses suggested that the reaction mechanism took place via two steps: the first step was formation of the amide linkage and the second step was formation of imide linkages.


2014 ◽  
Vol 77 (8) ◽  
pp. 1355-1360 ◽  
Author(s):  
JU-HYUN JEON ◽  
JUN-HWAN PARK ◽  
NAMHYUN CHUNG ◽  
HOI-SEON LEE

The acaricidal activities of an active material derived from Rosmarinus officinalis oil and its relative monoterpene ketones were determined using fumigant and contact toxicity bioassays against Tyrophagus putrescentiae and were compared with that of a commercial acaricide (benzyl benzoate). The active component of R. officinalis oil, isolated by silica gel column chromatography and high-performance liquid chromatography, was identified as camphor, based on various spectroscopic analyses. In the fumigant toxicity bioassay, camphor (2.25 μg/cm3) was 5.58 times more active than benzyl benzoate (12.56 μg/cm3) against T. putrescentiae, followed by (+)-camphor (3.89 μg/cm3) and (−)-camphor (5.61 μg/cm3). In the contact toxicity bioassay, camphor (1.34 μg/cm2) was 6.74 times more toxic than benzyl benzoate (9.03 μg/cm2) against T. putrescentiae, followed by (+)-camphor (2.23 μg/cm2) and (−)-camphor (2.94 μg/cm2). These results indicate that camphor and its derivatives are very useful as potential control agents against stored food mites regardless of the application method.


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6506-6525
Author(s):  
Safa Abdel-Kader Mohamed Hamed ◽  
Mohamed Z. M. Salem ◽  
Hayssam M. Ali ◽  
Kareem Mohamed El-Sayed Ahmed

A new perspective on the effect of unconditioned indoor (especially storage areas) and outdoor environments on wood acidity is provided in this work. A comparison between the quantity and types of the organic acids formed in the unconditioned indoor environment and different outdoor environments was made. Moreover, the acidity of some wood samples due to different environmental conditions was determined using a pH meter and high-performance liquid chromatography (HPLC). Fourier transform infrared (FTIR) was used to detect the changes in wood components at the molecular level due to environmental conditions. The results suggest that the unconditioned indoor environment was more aggressive than the outdoor environment with respect to wood deterioration. The polluted atmosphere increased the wood acidity and motivated polysaccharide breakdown.


Author(s):  
A. V. Crewe ◽  
M. Isaacson ◽  
D. Johnson

A double focusing magnetic spectrometer has been constructed for use with a field emission electron gun scanning microscope in order to study the electron energy loss mechanism in thin specimens. It is of the uniform field sector type with curved pole pieces. The shape of the pole pieces is determined by requiring that all particles be focused to a point at the image slit (point 1). The resultant shape gives perfect focusing in the median plane (Fig. 1) and first order focusing in the vertical plane (Fig. 2).


Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.


Author(s):  
John W. Coleman

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.


Author(s):  
J W Steeds ◽  
R Vincent

We review the analytical powers which will become more widely available as medium voltage (200-300kV) TEMs with facilities for CBED on a nanometre scale come onto the market. Of course, high performance cold field emission STEMs have now been in operation for about twenty years, but it is only in relatively few laboratories that special modification has permitted the performance of CBED experiments. Most notable amongst these pioneering projects is the work in Arizona by Cowley and Spence and, more recently, that in Cambridge by Rodenburg and McMullan.There are a large number of potential advantages of a high intensity, small diameter, focussed probe. We discuss first the advantages for probes larger than the projected unit cell of the crystal under investigation. In this situation we are able to perform CBED on local regions of good crystallinity. Zone axis patterns often contain information which is very sensitive to thickness changes as small as 5nm. In conventional CBED, with a lOnm source, it is very likely that the information will be degraded by thickness averaging within the illuminated area.


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