The search for a corpuscular theory of double refraction: Malus, Laplace and the price competition of 1808.
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History, 19th Century↗
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Results for “Optical Rotation”
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Synthesis and biological activity of prostaglandins and prostaglandin antagonists.
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Alcohols↗
Present status of the d-urobilins.
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Crystallization↗
Angular measurements of light scattered by turbid chiral media using linear Stokes polarimeter.
The effects of turbid chiral media on light polarization are studied in different directions around the scattering samples using a refined linear Stokes polarimeter, which simplifies the signal analysis, and allows for the detailed investigations of scattered light. Because no moving parts are involved in a measurement at a specific detection direction, the determination accuracy of polarization states is increased. The results show that light depolarization increases with both turbidity and detection angle for low and moderately turbid samples; however, the angular dependence decreases with increasing turbidity. When the turbidity is increased to approximately 100 cm(-1), the depolarization becomes higher in the forward than in the backward direction. Polarization sensitive Monte Carlo simulations are used to verify some experimental observations. The results also demonstrate that surviving linear polarization fraction and overall intensity are more sensitive to the increase of glucose concentration in backward than in the forward direction in highly turbid media, indicating that backward geometry may be preferable for potential glucose detection in a biomedical context. Comparison measurements with optically inactive glycerol suggest that the refractive index matching effect, and not the chiral nature of the solute, dominates the observed optical rotation engendered by glucose in highly turbid media.
Equipment Design↗
I-OCTOPAMINE IN CITRUS: ISOLATION AND IDENTIFICATION.
l-Octopamine, [l-p-hydroxy-alpha-(aminomethyl)benzyl alcohol], has been isolated and identified from extracts of juice and leaves of the Meyer lemon. Identification was by chromatography, optical rotation, ultraviolet absorption curves, fluorescence spectra, and infrared spectroscopy. l-Octopamine has not previously been isolated and identified from plants.
Chromatography↗
Synthesis of [C]Cellobiose with Clostridium thermocellum Cellobiose Phosphorylase.
Cellobiose labeled either at the reducing end (4-O-beta-d-glucopyranosyl-d-[U-C]glucopyranose) or at the nonreducing end (4-O-beta-d-[U-C]glucopyranosyl-d -glucopyranose) was synthesized with Clostridium thermocellum cellobiose phosphorylase at greater than 98% purity. The radioactive cellobioses were identical to authentic cellobiose in melting point, optical rotation, isotopic dilution, and chromatographic properties.
Journal Article↗
Purification and characterization of anti-Listeria compounds produced by Geotrichum candidum.
Geotrichum candidum can produce and excrete compounds that inhibit Listeria monocytogenes. These were purified by ultrafiltration, centrifugal partition chromatography, thin-layer chromatography, gel filtration, and high-pressure liquid chromatography, and analyzed by liquid chromatography-mass spectrometry, infrared spectrometry, nuclear magnetic resonance spectrometry, and optical rotation. Two inhibitors were identified: D-3-phenyllactic acid and D-3-indollactic acid.
Anti-Bacterial Agents↗
Production of 2,3-butylene glycol from citrus wastes. II. The Bacillus polymyxa fermentation.
The conditions required for production of levo 2,3-butylene glycol by Bacillus polymyxa from citrus molasses were studied. Starter cultures required acclimatization to the substrate prior to inoculation of the fermentation medium. Maximal production of butylene glycol with minimal residual sugar was obtained with a medium consisting of molasses, diluted to 20 degrees Brix, and 0.4% urea. Optimal environmental conditions included aeration at 0.11 volumes of air per volume of medium per minute, maintenance of pH at 6.0 to 6.2, a fermentation temperature of 30 C, and a stirring rate of 420 rev/min. The concentration of butylene glycol obtained in the fermentation beer ranged from 2.3 to 4.4%. The optical rotation of the glycol ranged from [alpha](D) (23 degrees ) = -1.01 degrees to -10.45 degrees . The variation in rotation was probably due to the presence of contaminating substances in the distillate.
Bacillus↗
Flocculant and chemical properties of a polysaccharide from Pullularia pullulans.
An extracellular polysaccharide, PP-floc, was synthesized from glucose by Pullularia pullulans (or Aureobasidium pullulans) in a pilot plant batch fermentor containing 175 liters of culture medium. At 58 h of fermentation, the concentration of PP-floc was 1.03 g/100 ml, giving a 25.8% conversion of initial glucose to polysaccharide. The flocculant activity of the culture medium increased during the fermentation process and reached its maximum at 50 h of culture age. Less PP-floc (0.33 lb/ton of slimes [approximately 149.7 g/0.907 t]) was required to give the same flocculant activity as a synthetic polymer of acrylamide, Separan NP-10 (0.5 lb/ton of slimes [approximately 226.8 g/0.907 t]), at all temperatures from 25 to 100 C. The degree of inactivation of PP-floc and Separan NP-10 at elevated temperatures was almost identical, and they were completely inactivated at about the same temperature (80 C). PP-floc also gave better compaction of slimes than Separan NP-10 at all temperatures tested. PP-floc was soluble in water and its specific optical rotation was [alpha](D) (25) + 194 degrees in water (c, 0.4). PP-floc contained 83.3% carbohydrate, 3.2% protein, and 8.1% water. Glucose was found to be the principal sugar monomer with traces (>5%) of galactose and mannose present. Structural studies on the fractions of purified polysaccharide by methylation and by periodate oxidation techniques prove that PP-floc is linear and composed of alpha-(1 --> 4) and alpha-(1 --> 6) glucopyranosyl units in the approximate ratio of 2:1. The action of pullulanase on crude PP-floc suggested the ordered arrangement of two consecutive alpha-(1 --> 4)-linked glucopyranosyl units flanked by alpha-(1 --> 6)-linked glucopyranose residues.
Carbohydrates↗
Immunochemical and structural characterization of a serotype-specific polysaccharide antigen from Actinobacillus actinomycetemcomitans Y4 (serotype b).
A serotype-specific polysaccharide antigen of Actinobacillus actinomycetemcomitans Y4 (serotype b) was extracted from whole cells by autoclaving. The extract was purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300 columns. The purified polysaccharide antigen formed a single precipitin line with anti-type b serum but not with anti-type a serum and anti-type c serum. The antigen was composed of 43.9% L-rhamnose, 49.1% D-fucose, and a trace amount of fatty acid. Methylation analysis, Smith degradation, and optical rotation data showed that the antigen was a polymer consisting of a disaccharide repeating unit, ----3)-alpha-D-fucopyranosyl-(1----2)-beta-L-rhamnopyranosyl-(1----. In quantitative precipitin inhibition tests, D-fucose and L-rhamnose showed very low inhibition, but the partial hydrolysate of the purified antigen was an effective inhibitor, suggesting that the serotype b specific antiserum recognizes the larger oligosaccharide units.
Actinobacillus↗
Galactosaminogalactan from cell walls of Aspergillus niger.
A new heteropolysaccharide has been isolated by alkaline extraction of hyphal walls of Aspergillus niger NRRL 326 grown in surface culture. Its composition by weight, as determined by paper and gas chromatography and colorimetric analyses, is 70% galactose, 20% galactosamine, 6% glucose, and 1% acetyl. Two independent experiments have been used to ascertain copolymer structure: permeation chromatography in 6 M guanidinium hydrochloride, with controlled-pore glass columns of two fractionation ranges, and nitrous acid deaminative cleavage of galactosaminogalactan followed by reduction of fragments with [3H]borohydride and gel filtration chromatography. One of the tritiated fragments is tentatively identified as the disaccharide derivative galactopyranosyl 2,5-anhydrotalitol, on the basis of chromatographic properties and by kinetics of its acid hydrolysis. Smith degradation, methylation, deamination, and optical rotation studies indicate that the galactosaminogalactan consists of a linear array of hexopyranosyl units joined almost exclusively by alpha-(1 leads to 4) linkages. Hexosaminyl moieties are distributed randomly along the chains, which have an average degree of polymerization of about 100. The possible significance of this macromolecule in hyphal structure is considered.
Aspergillus↗
Chemical and immunological studies on mycobacterial polysaccharides. 1. Purification and properties of polysaccharides from human tubercle bacilli.
Defatted human tubercle bacilli, Aoyama B strain, were extracted with 0.1 n NaOH for 24 hr, and the crude polysaccharide fraction was precipitated by the addition of 5 volumes of ethyl alcohol. A yield of 17.8 g of crude polysaccharides was obtained from 800 g of bacilli. The crude polysaccharide was further fractionated into seven fractions by fractional precipitation with ethyl alcohol. Each fraction was purified by successive chromatography on Dowex 50 and diethylaminoethyl cellulose, and by gel filtration on Sephadex G-75 and G-200. Optical rotation and gas chromatographic analyses of purified polysaccharide showed that these polysaccharides contained glucan mannan, arabinomannan, and arabinogalactan. Each polysaccharide was almost completely free from nitrogen, and no tuberculin reaction was produced by 100 mug of each material. Arabinomannan and arabinogalactan showed precipitin reaction, complement fixation, and passive hemagglutination reaction with rabbit antiserum against heat-killed whole bacilli (Aoyama B). In guinea pigs sensitized with Aoyama B bacilli, arabinomannan and arabinogalactan provoked anaphylactic shock when injected intravenously, and Arthus type reaction when injected intracutaneously. With the use of rabbit antiserum, arabinomannan and arabinogalactan showed passive anaphylactic shock, passive cutaneous anaphylaxis, and Prausnitz-Küstner type reactions in guinea pigs. By immunodiffusion analysis, it was shown that the antigenic determinant of arabinomannan was different from that of arabinogalactan.
Animals↗
Excretion patterns of glycosaminoglycans and glycoproteins in normal human urine.
Glycosaminoglycans and glycoproteins in the urine of 100 healthy, active, human subjects were examined by cellulose acetate electrophoresis and salt gradient, ion-exchange, column chromatography. The cetylpyridinium chloride (CPC) turbidity and uronic acid:creatinine ratio was also studied. Fractions were identified by electrophoretic mobility, staining reactions, susceptibility to enzyme digestion, identification of amino- and neutral sugars, hexosamine, uronic acid, and sulphate assays, and optical rotation. The CPC turbidity is relatively high in childhood, falling to lower levels in adults, but rising again to relatively high levels in old age. The uronic acid: creatinine ratio is high in children, falling to a low level in adult life, and rising only slightly in old age. Three major electrophoretic fractions, corresponding with glycoprotein, heparan sulphates, and chondroitin sulphates, were identified in every urine sample. Hyaluronic acid was identified in some samples. A small amount of keratan sulphate was present in the ;heparan sulphate' fraction. Chondroitin sulphate excretion is high in children. Adults excrete relatively less chondroitin sulphate and more heparan sulphate. In old age, the proportion of glycoprotein increases. The excretion pattern in the first few days of life resembles that of the adult. It is stressed that extreme caution must be exercised in interpreting the urinary glycosaminoglycan pattern of a child.
Adolescent↗
Structure of the D-glucans produced by Neisseria perflava.
A chemical and enzymic study of the cellular glucan of Neisseria perflava and of the glucan produced from sucrose by a cell-free extract of N. perflava showed from optical rotation, 13C nuclear magnetic resonance, methylation analysis, and alpha- and beta-amylase hydrolysis studies that the glucans had glycogen-like structures. These structures were composed of chains of 1-4-alpha-D-glucopyranosyl units with branch points of 4-O- and 6-O-disubstituted D-glucopyranose units. While the backbone structures of the two glucans were similar, the release of maltose by the action of beta-amylase indicated that the 1-4 linked nonreducing side chains of the cell-free enzymically synthesized glucan were longer (approximately seven units) than those present in the cellular glucan (approximately two to three units), a result in agreement with methylation analyses.
Cell-Free System↗
Structure of the exocellular D-glucan produced by Neisseria polysaccharea.
Neisseria polysaccharea (LNP 462, NCTC 11858), proposed as a prototype strain constituting a new taxon in the genus Neisseria, produces copious amounts of polysaccharide when grown on agar containing 1-5% sucrose. Plate-grown cells produced an exocellular polysaccharide which was composed of D-glucose, had [alpha]D +222 degrees (water), and was shown from composition, specific optical rotation, methylation, enzymic hydrolysis, and 13C nuclear magnetic resonance studies to have an amylopectinlike structure containing mainly 1,4-linked alpha-D-glucopyranosyl residues, but also containing ca. 6% 4,6-di-O-substituted alpha-D-glucopyranosyl branch points.
Centrifugation↗
Synthesis of 1-sn-lysophosphatidylcholine and mixed acid 1-sn-phosphatidylcholine.
An investigation of the biochemical effects of L-lysophosphatidylcholine (1-acyl-sn-glycerol-3-phosphorylcholine) requires as a control for its detergent action the metabolically inert, unnatural enantiomer, D-lysophosphatidylcholine (3-acyl-sn-glycerol-1-phosphorylcholine). The latter can be easily prepared in milligram quantities from the commercially available DL-phosphatidylcholine. For this purpose rac-1,2-dipalmitoyl-sn-glycerol-3-phosphorylcholine is solubilized with the aid of one-half its weight of taurocholate and hydrolyzed with phospholipase A2 to completion and the intact residual 2,3-dipalmitoyl-sn-glycerol-1-phosphorylcholine recovered by chromatography. The pure D-phosphatidylcholine is then subjected to methanolysis in the presence of octylamine and the product isomerized with glacial acetic acid. The 3-palmitoyl-sn-glycerol-1-phosphorylcholine thus obtained is chromatographically pure, possesses correct optical rotation and NMR spectrum, and is resistant to hydrolysis by phospholipase A2 following reacylation to the diacylphosphatide. Acylation of the 1-sn-lysophosphatide provides a convenient method for preparation of mixed acid 1-sn-phosphatidylcholines which are not otherwise available.
Isomerism↗
Chemical synthesis of sn-3-phosphatidyl sulfocholine, a sulfonium analog of lecithin.
A sulfonium analog of lecithin has been reported to replace the ubiquitous phosphatidyl choline in a non-photosynthetic diatom, Nitzschia alba. The structure of this sulfonium analog has now been established by chemical synthesis using the following methods: (i) condensation of sn-3-phosphatidic acid (dimyristoyl-, dipalmitoyl-, distearoyl-, distearoyl-, and dioleoyl-) with sulfocholine chloride in the presence of triisopropylbenzenesulfonylchloride in chloroform-pyridine (9:1); and (ii) phosphorylation of 1,2-dipalmitoyl-sn-glycerol with monophenylphosphoryl-dichloridate followed by a reaction with sulfocholine in the presence of pyridine and finally removal of the blocking phenyl group by catalytic hydrogenolysis. The desired synthetic products were obtained in overall yields of 50-70% and 11% for methods (i) and (ii), respectively, and were characterized by elemental analyses; infrared spectroscopy, nuclear magnetic resonance spectrometry, and mass spectrometry; optical rotation; and thin-layer chromatography mobilities. Comparison of the synthetic analogs with the natural sulfolecithin showed them to be identical, except for the nature of the fatty acid chains, thus establishing the natural product as sn-3-phosphatidyl sulfocholine.
Magnetic Resonance Spectroscopy↗
The specific capsular polysaccharide of Streptococcus pneumoniae type 9V.
The specific capsular polysaccharide produced by Streptococcus pneumoniae type 9V (American type 68) is composed of D-glucuronic acid (1 part), D-galactose (1 part), 2-acetamido-2-deoxy-D-mannose (1 part), D-glucose (2 parts), and O-acetyl (1.6 parts). Methylation, periodate oxidation, optical rotation, and nuclear magnetic resonance studies, and partial hydrolysis showed that the polysaccharide is an unbranched high molecular weight linear polymer of a partially O-acetylated pentasaccharide repeating unit having the structure indicated below. (Formula: see text).
Chemical Phenomena↗