Structure of the O-polysaccharide of Hafnia alvei strain PCM 1189 that has hexa- to octasaccharide repeating units owing to incomplete glucosylation

The O-polysaccharide of Hafnia alvei PCM 1189 consists of D-glucose, D-galactose, D-GalNAc and D-GlcA and lacks the strict regularity. The intact and carboxyl-reduced polysaccharides as well as oligosaccharides obtained by partial acid hydrolysis were studied by chemical and enzymatic analyses, methylation and NMR spectroscopy. The following structure was established for the O-polysaccharide, which is built up of branched hexa- to octasaccharide repeating units differing in the number of lateral glucose residues: [structure: see text] where the glucose residues shown in italics are nonstoichiometric substituents. The repeating units include also a minor O-acetyl group, whose position was not determined.     

Analysis of monosaccharides, fatty constituents and rare O-acetylated sialic acids from gonads of the starfish Asterias rubens

A previous study (Bergwerff et al., Biochimie 74 (1992) 25-37) reported that sialic acids present in Asterias rubens gonads were essentially composed of 8-methyl-N-glycolylneuraminic acid (Neu5Gc8Me), a large part of it being acetylated in position 9. Using GC/MS of heptafluorobutyrate derivatives (Zanetta et al., Glycobiology 11 (2001) 663-676) on the chloroform/methanol soluble and insoluble fractions, we showed that most sialic acids were found in the latter and demonstrated that all sialic acids were derived from N-glycolylneuraminic acid, most of them being 8-methylated, but that the majority were also acetylated in position 4 or 7 (or both positions). GC/MS analyses of the constituents liberated using acid-catalysed methanolysis verified that major glycoprotein-bound glycans were N-linked and of the gluco-oligomannosidic type. Major fatty acids were poly-unsaturated (especially C20:4) and long-chain bases were C22:1 phytosphingosine and C22:2 6-hydroxysphingenine. Major monosaccharides found in the chloroform/methanol extract (quinovose and fucose) were derived from steroidal saponins.     

Structural studies of the capsular polysaccharide of a non-neoformans Cryptococcus species identified as C. laurentii, which was reclassified as Cryptococcus flavescens, from a patient with AIDS

Cryptococcus flavescens, a strain originally identified as C. laurentii, was isolated from the cerebrospinal fluid of an AIDS patient, and the soluble capsular polysaccharide of the yeast was investigated. Glucuronoxylomannan (GXM) was obtained from C. flavescens under conditions similar to those used to obtain C. neoformans polysaccharide. However, the GXM differed from C. neoformans polysaccharide in the decreased O-acetyl group content. The structure of GXM was determined by methylation analysis, partial acid hydrolysis, NMR analyses, and controlled Smith degradation. These analyses indicated that GXM has the following structure: an alpha-(1-->3)-D-mannan backbone with side chains of beta-D-glucuronic acid residues bound to the C-2 position of the mannose residue. The C-6 position of the mannose is substituted with D-man-beta-(1-->4)-D-xyl-beta-(1--> disaccharide. Furthermore, the existence of side chains containing more than two xylose residues was suggested. This mannosylxylose side chain is a novel structure in polysaccharides of C. neoformans and other Cryptococcus species.     

Immunoregulatory effects of a glucogalactan from the root of Panax quinquefolium L.

In this research we purified one homogeneous glucogalactan from the roots of Panax quinquefolium, with a molecular weight of 54 kDa estimated by high-performance gel permeation chromatography (HPGPC). The monosaccharide composition of PPQ was composed of Glc (glucose) and Gal (galactose) in a molar ratio of 2.1:1, as determined by gas chromatography (GC). In order to evaluate the anti-lung carcinoma and immunoregulatory effects of this glucogalactan in mice, we established a Lewis lung carcinoma model in C57BL/6 mouse. The results showed that PPQ not only could inhibit the growth of lung tumor, but also enhance the thymus and spleen indices, as well as the level of IFN-γ, IL-10 and IL-2, indicating PPQ could have a possible cancer therapeutic potential.     

Clonorchis sinensis: codon usage in nuclear genes

Codon usage in Clonorchis sinensis was analyzed using 12,515 codons from 38 coding sequences. Total GC content was 49.83%, and GC1, GC2 and GC3 contents were 56.32%, 43.15% and 50.00%, respectively. The effective number of codons converged at 51-53 codons. When plotted against total GC content or GC3, codon usage was distributed in relation to GC3 biases. Relative synonymous codon usage for each codon revealed a single major trend, which was highly correlated with GC content at the third position when codons began with A or U at the first two positions. In codons beginning with G or C base at the first two positions, the G or C base rarely occurred at the third position. These results suggest that codon usage is shaped by a bias towards G or C at the third base, and that this is affected by the first and second bases.     

Deoxyribonucleic acid base composition of pediococci and aerococci

Summary The guanine+cytosine content (GC) of DNAs of 9 strains of pediococci and 6 strains of aerococci was determined using different physicochemical methods. It was found that the GC content of DNA of the pediococci ranged from 37.8 to 41.2%, while that of the aerococci varied from 42.0 to 43.2%. The results obtained show that genetically related species are involved whose mutual position in the system is determined by only slight differences in the phenotype.     

Glucose uptake and metabolism in the Trichinella spiralis nurse cell

Isolated Trichinella spiralis nurse cells transport a significantly greater amount of glucose/mg of protein than the normal skeletal muscle cell line (L6). V(max) and K(m) estimations revealed that nurse cells have a much higher saturation point than L6 cells for glucose. The effects of numerous physiological conditions (Na(+) concentration, pH, and temperature) on nurse cell glucose uptake were investigated. It was determined that sodium concentration had no effect on glucose uptake. Low (<6.5) and high (>7.3) pH and low (5 degrees C) temperatures significantly effected glucose uptake. The two hormones, insulin and epinephrine, appeared to have little, if any, influence on the rate of glucose uptake by nurse cells. Glucose uptake was inhibited in the presence of 6-carbon carbohydrates. The H(+)/glucose symport inhibitors, dicyclohexylcarbodiimide (DCCD) and Carbonyl cyanide 4-trifluoromethoxyphenlhydrazone (FCCP), and the facilitated diffusion inhibitor phloretin also inhibited glucose uptake. Oubain, a Na(+)/glucose symport inhibitor, did not inhibit glucose uptake. These data, in conjunction with Western blot analyses, revealed that the transport of glucose occurs via H(+)/glucose symport and facilitated diffusion, perhaps through the glucose transport proteins GLUT 1 and/or 4. It was also demonstrated that nurse cells are capable of synthesising glycogen. It appears that glycogen is in a constant state of flux and physiological conditions, such as glucose concentration, significantly influence the synthesis of this macromolecule. We conclude that these results are consistent with the hypothesis that nurse cells, at least maintained in vitro, are metabolically highly active but show significant divergence from normal muscle cells in several fundamental aspects of sugar metabolism.     

Deoxyribonucleic Acid Base Composition of Species in the Yeast Genus Kluyveromyces van der Walt emend. van der Walt

The deoxyribonucleic acid base composition (percent guanine + cytosine [GC]) was determined for 29 strains, representing 18 species of the genus Kluyveromyces. It was concluded that on the basis of GC content (47.4%) and other properties K. veronae occupies an uncertain position in the genus Kluyveromyces. The GC content of the remaining 17 species ranged from 35.3 to 43.4%, and three groups of species were recognized. The GC content of the first ranged from 35.3 to 38.0%; that of the second group from 39.5 to 41.7%; that of the third group from 42.4 to 43.4%. Several species revealed a nearly identical GC content. The GC contents do not correspond in all instances with the five groups of species proposed by van der Walt.     

聚酰胺树脂分离纯化芦荟多糖的研究

文章采用聚酰胺吸附树脂,采用水、0．2M／LNaCl溶液、5％NaOH水溶液为洗脱剂梯度洗脱分离纯化,得到了三个芦荟多糖组分,通过IR、UV、GC等手段对其进行了分析。以甘露糖为标准,采用硫酸．苯酚法,测得水洗和NaOH水溶液洗脱所得多糖含量分别为90．10％和93．28％;以木糖、甘露糖、葡萄糖、半乳糖为单糖标准的GC分析结果显示：水洗所得多糖主要以甘露糖为主,同时含有少量的葡萄糖。     

Essential oil variation within and among natural populations of Lavandula latifolia and its relation to their ecological areas

Essential oil yield and composition in seven natural populations of Lavandula latifolia from the eastern Iberian Peninsula were determined by GC/MS. Twenty-eight constituents were identified, accounting for 92.0–95.4% of the total oils. These oils were dominated by the monoterpene fraction and three of them (linalool, cineole and camphor) constituted 79.5–86.9% of the oil from flowers. Essential oil yield in leaves and flowers varied among and within populations, but hierarchic analyses of variance showed that the proportion of variation attributable to individuals was significantly higher than that attributable to population differences. Principal component and cluster analyses allowed three groups of flower essential oils to be distinguished according to their high, intermediate and low proportion of linalool. These essential oil types are respectively correlated to the Supra-, Meso- and Thermo-Mediterranean bioclimatic belts where the populations are located. A genetic analysis based on those terpenes that showed a trimodal distribution roughly corroborated the relationships between the seven populations obtained from the ordination analyses and emphasizes the distinctiveness of some of the populations.     

Novel acetylated alpha-cyclosophorotridecaose produced by Ralstonia solanacearum

Alpha-cyclosophorotridecaose (alpha-C13) produced by Ralstonia solanacearum is isolated by trichloroacetic acid treatment and subjected to various chromatographic techniques. Here, we report for the first time that R. solanacearum produces acetylated alpha-C13. Structural analyses of the acetylated alpha-C13 were performed with 1D or 2D NMR spectroscopy, MALDI-TOF MS and HPLC. The results show that the alpha-C13 is substituted by mainly one acetyl residue at the C-6 position of the glucose unit.     

Condition dependent intra-individual repeatability of stress-induced cortisol in a freshwater fish

The glucocorticoid (GC) stress response is thought to be an individual trait associated with behaviour and life history strategies. Studies exploring such relationships typically assume measured hormone values to be repeatable within an individual. However, repeatability of GCs has proven variable in wild animals and underlying reasons remain unknown. We assessed individual repeatability of circulating stress-induced cortisol, the primary GC in teleost fish, and glucose concentrations in a wild teleost fish held under consistent laboratory conditions. We also tested the hypothesis that the magnitude of intra-individual variability in stress-induced cortisol concentrations (“cortisol variability”) is influenced by body condition. Wild-caught bluegill sunfish (Lepomis macrochirus) were subjected to repeated standardized stressors and blood sampled (3 times over 6 days) once cortisol concentrations peaked. Various indicators of fish condition, both whole body and physiological, were also measured. Overall, stress-induced circulating cortisol concentrations were repeatable but stress-induced glucose was not. Cortisol variability was related to Fulton's condition factor and size (eviscerated mass) where smaller fish in poor condition exhibited increased cortisol variability. The findings have implications for the interpretation of studies that examine correlates of GC concentrations as they suggest consistency in stress responsiveness is influenced by factors such as size and condition.     

Deoxyribonucleic acid binding studies on several new anthracycline antitumor antibiotics. Sequence preference and structure--activity relationships of marcellomycin and its analogues as compared to adriamycin.

The deoxyribonucleic acid (DNA) binding characteristics of adriamycin and several new anthracycline glycosides, including marcellomycin, aclacinomycin, rudolfomycin, musettamycin, and pyrromycin, have been studied. The fluorescence spectra were determined for all six anthracyclines, and the fluorescence quenching effects caused by interactions with the natural DNAs poly(dAdT)--poly(dAdT) and poly(dGdC) were characterized. Binding parameters were determined by Scatchard analyses of results obtained by spectrofluorometric titrations of anthracyclines with DNA. Consistent with earlier structure--activity relationship studies of nucleic acid synthesis inhibitory effects, the results demonstrate a correlation between the length of the glycosidic side chain and DNA binding affinity. In addition, the sugar residue 2-deoxyfucose appears to confer greater DNA binding ability than do the sugars rednosamine and cinerulose when present in the terminal position of the glycosidic side chain, also in agreement with earlier studies. The sequence preference of anthracycline--DNA interaction has been examined by using DNAs of varying GC content, including the naturally occurring calf thymus DNA (43% GC), Clostridium perfringens DNA (28% GC), and Micrococcus luteus DNA (72% GC) and the synthetic double-stranded copolymers poly(dGdC)--poly(dGdC) and poly(dAdT)--POLY(DAdT). The results demonstrate that although adriamycin shows an absolute requirement for GC sequences for DNA binding, marcellomycin and its analogues showed no such sequence requirement. Furthermore, an AT preference for DNA binding was demonstrated with marcellomycin and its analogues.     

Purification, characterization cloning, and sequencing of metalloendopeptidase from Streptomyces septatus TH-2

Streptomyces septatus TH-2 secretes a large amount of a protease when cultured on a medium containing K(2)HPO(4) and glucose. The enzyme was purified to homogeneity by a three-step procedure. This enzyme had a molecular mass of approximately 35kDa, and was particularly inhibited by EDTA and phosphoramidon. Its substrate specificity was investigated using novel fluorescence energy transfer combinatorial libraries. The protease was found to prefer Phe and Tyr at the P(1) position, a hydrophobic or basic residue at the P(2) position, and a basic or small residue at the P(3) position. Its gene was cloned and sequenced, and its deduced amino acid sequence contained an HEXXH consensus sequence for zinc binding, confirming that it encodes metalloendopeptidase. The primary structure of the enzyme showed 40 and 69% identities with that of thermolysin from Bacillus thermoproteolyticus and that of a metalloendopeptidase from Streptomyces griseus, respectively.     

Hydroxylation of carbazoles by Aspergillus flavus VKM F-1024

Carbazole was metabolized by Aspergillus flavus VKM F-1024 forming few monohydroxylated products. The structure of metabolites was determined by TLC, GC, MS and (1)H NMR analyses. 3-Hydroxycarbazole was revealed as a major bioconversion product, 1-hydroxy- and 2-hydroxycarbazoles were observed as minor products. In the presence of 1-benzoylindole, the hydroxylation position shifted toward preferable accumulation of 2-hydroxycarbazole and the formation of 2,6- and 2,7-dihydroxycarbazoles. This effect and microbial formation of these metabolites have never been reported before. At the conversion of N-acetyl- and N-benzoylcarbazoles, carbazole was the major product, while 1-, 2- and 3-monohydroxycarbazoles were formed in small amounts.     

Determination of the structure and degree of polymerisation of fructans from Echinacea purpurea roots

Highly water soluble fructans have been isolated from Echinacea purpurea (L.) Moench. roots by hot water extraction and precipitation at three different ethanol concentrations (80% v/v, 60% v/v and 40% v/v). The structure of the fructans has been characterised by three analytical methods: GC of silylated oxime derivatives and partially methylated alditol acetates, respectively, as well as 13C NMR analysis. The mean degree of polymerisation (mean DP) of each fructan has been determined by the glucose/fructose ratio. E. purpurea fructans represent linear inulin-type fructans with almost exclusively beta-(2-->1)-linked fructosyl units, terminal glucose and terminal fructose. Small proportions of beta-(2-->1,2-->6)-linked branch point residues were detected. The mean DP of the fructan fractions depends on the ethanol concentration used for precipitation: the lower the ethanol concentration the higher the mean DP. Corresponding results were found with all of the three analytical methods: 80% ethanol-insoluble fructan from E. purpurea shows an average mean DP of 35, 60% ethanol-insoluble fructan of 44 and 40% ethanol-insoluble fructan of 55. The applied methods provide sufficient sensitivity to determine not only the composition and structure but also the mean degree of polymerisation of fructans.     

Volatile oil from Guarea macrophylla ssp. tuberculata: seasonal variation and electroantennographic detection by Hypsipyla grandella

GC and GC-MS analyses of the volatile oils from Guarea macrophylla (Meliaceae) collected during three different periods in one year (February, June and October) indicated a seasonal variation in chemical composition. Whilst sesquiterpenes were the predominant class of components present in the leaf oil, a seasonal dependent variation in the degree of oxygenation of these compounds was detected, which seemed to be associated with phenological factors. The leaf oil, and fractions thereof, were subjected to GC coupled with electroantennographic detection employing antennae of females of Hypsipyla grandella, an insect pest that attacks several meliaceous species. Five compounds elicited significant responses and these were identified as ledol, 1-cubenol, guai-6-en-10beta-ol, 1-epi-cubenol, and tau-muurolol. The results suggest that these components could be responsible for the attraction of H. grandella to G. macrophylla.     

Inhibition of eIF5A hypusination reprogrammes metabolism and glucose handling in mouse kidney

Inhibition of the eukaryotic initiation factor 5A activation by the spermidine analogue GC7 has been shown to protect proximal cells and whole kidneys against an acute episode of ischaemia. The highlighted mechanism involves a metabolic switch from oxidative phosphorylation toward glycolysis allowing cells to be transiently independent of oxygen supply. Here we show that GC7 decreases protein expression of the renal GLUT1 glucose transporter leading to a decrease in transcellular glucose flux. At the same time, GC7 modifies the native energy source of the proximal cells from glutamine toward glucose use. Thus, GC7 acutely and reversibly reprogrammes function and metabolism of kidney cells to make glucose its single substrate, and thus allowing cells to be oxygen independent through anaerobic glycolysis. The physiological consequences are an increase in the renal excretion of glucose and lactate reflecting a decrease in glucose reabsorption and an increased glycolysis. Such a reversible reprogramming of glucose handling and oxygen dependence of kidney cells by GC7 represents a pharmacological opportunity in ischaemic as well as hyperglycaemia-associated pathologies from renal origin.Subject terms: Cell biology, Physiology     

An Endoreticulatus species from Ocinara lida (Lepidoptera: Bombycidae) in Taiwan

A microsporidium from the Ficus pest, Ocinara lida, in Taiwan is characterized. The taxonomic position of this species was preliminarily determined by sequencing small subunit rRNA gene (SSUrRNA). Analysis of the SSUrRNA sequence indicated that this isolate from O. lida is a member of the genus Endoreticulatus and belongs to the genetic grouping containing other lepidopteran Endoreticulatus species we have analyzed phylogenetically. The taxonomic position of this isolate was also confirmed by the ultrastructural characteristics of this isolate. The congruence between SSUrRNA sequence analysis and ultrastructural characteristics shows that this isolate is more closely related to Endoreticulatus bombycis than to Endoreticulatus schubergi Zw?lfer.     

Structural determination of the lipo-chitin oligosaccharide nodulation signals produced by Rhizobium giardinii bv. giardinii H152

Rhizobium giardinii bv. giardinii is a microsymbiont of plants of the genus Phaseolus and produces extracellular signal molecules that are able to induce deformation of root hairs and nodule organogenesis. We report here the structures of seven lipochitooligosaccharide (LCO) signal molecules secreted by R. giardinii bv. giardinii H152. Six of them are pentamers of GlcNAc carrying C 16:0, C 18:0, C 20:0 and C 18:1 fatty acyl chains on the non-reducing terminal residue. Four are sulfated at C-6 of the reducing terminal residue and one is acetylated in the same position. Six of them are N-methylated on the non-reducing GlcN residue and all the nodulation factors are carbamoylated on C-6 of the non-reducing terminal residue. The structures were determined using monosaccharide composition and methylation analyses, 1D- and 2D-NMR experiments and a range of mass spectrometric techniques. The position of the carbamoyl substituent on the non-reducing glucosamine residue was determined using a CID-MSMS experiment and an HMBC experiment.