Simultaneous determination of the enantiomers of leucine and [H7]leucine in plasma by capillary gas chromatography–mass spectrometry

A method for the stereoselective assay of - and -enantiomers of both leucine and [²H₇]leucine in rat plasma was developed using gas chromatography–mass spectrometry–selected-ion monitoring. -[²H₃]leucine was used as an internal standard. The method involved purification by cation-exchange chromatography using BondElut SCX cartridge and derivatization with hydrochloric acid in methanol to form methyl ester followed by subsequent chiral derivatization with (+)-α-methoxy-α-trifluoromethylphenylacetyl chloride to form diastereomeric amide. The derivatization made the separation of the leucine enantiomers possible with good gas chromatographic behavior. Quantitation was performed by selected-ion monitoring of the quasi-molecular ions of the diastereomers on the chemical ionization method. The sensitivity, specificity, accuracy and reproducibility of the method were demonstrated to be satisfactory for application to pharmacokinetic studies of leucine enantiomers.     

Tryptophanase in aqueous methanol: the solvent effects and a probable mechanism of the hydrophobic control of substrate specificity

To shed light on the mechanism of hydrophobic control in reactions of microbial tryptophanase the direct effect of the solvent hydrophobicity on affinities of amino acid inhibitors was first examined. Values of inhibition constants (K_i) for a variety of amino acids were determined in 37.5% aqueous methanol, and no general correlation between the change of K_i, on passing from water to aqueous methanol, and amino acid hydrophobicity was found. The solvent effects on the separate stages of the external aldimine formation (K_D) and deprotonation to form a quinonoid intermediate (K_q) were determined for the reactions of tryptophanase with 2-oxindolyl- -alanine and -alanine by stopped-flow technique. For 2-oxindolyl- -alanine, which is a close transition-state analogue for the enzyme reaction with natural substrate, the decrease in the affinity in aqueous methanol is associated exclusively with the α-proton abstraction stage but not with the preceding formation of external aldimine. We conclude that the environment of amino acid side chains in the active site cannot be considered to be permanently hydrophobic irrespective of the bound amino acid. We suggest that complexes of tryptophanase with amino acids may exist either in a hydrophobic, presumably “closed”, conformation, where bound amino acids are isolated from the solvent, or in an accesible to solvent, “open”, conformation, depending on the structure of the bound amino acid and stage of the catalytic mechanism. For 2-oxindolyl- -alanine the transfer from an open to a closed conformation probably accompanies deprotonation of the external aldimine. The change of the active site hydrophobicity may provide an efficient way of modulating the relative acid–base properties of the catalytic groups to ensure the movement of protons in the “correct” direction depending on the elementary stage of catalysis.     

Evolution under the multilocus Levene model without epistasis

Evolution under the multilocus Levene model is investigated. The linkage map is arbitrary, but epistasis is absent. The geometric-mean fitness, , depends only on the vector of gene frequencies, ρ; it is nondecreasing, and the single-generation change is zero only on the set, Λ, of gametic frequencies at gene-frequency equilibrium. The internal gene-frequency equilibria are the stationary points of . If the equilibrium points of ρ(t) (where t denotes time in generations) are isolated, as is generic, then ρ(t) converges as t→∞ to some . Generically, ρ(t) converges to a local maximum of . Write the vector of gametic frequencies, p, as , where d represents the vector of linkage disequilibria. If is a local maximum of , then the equilibrium point is asymptotically stable. If either there are only two loci or there is no dominance, then d(t)→0 globally as t→∞. In the second case, has a unique maximum and is globally asymptotically stable. If underdominance and overdominance are excluded, and if at each locus, the degree of dominance is deme independent for every pair of alleles, then the following results also hold. There exists exactly one stable gene-frequency equilibrium (point or manifold), and it is globally attracting. If an internal gene-frequency equilibrium exists, it is globally asymptotically stable. On Λ, (i) the number of demes, Γ, is a generic upper bound on the number of alleles present per locus; and (ii) if every locus is diallelic, generically at most Γ−1 loci can segregate. Finally, if migration and selection are completely arbitrary except that the latter is uniform (i.e., deme independent), then every uniform selection equilibrium is a migration-selection equilibrium and generically has the same stability as under pure selection.     

Rac-1-mediated O2secretion requires Cainflux in neutrophil-like HL-60 cells

Neutrophil-like HL-60 cells reacted to N -formyl- -Methionyl- -Leucyl- -P henylalanine (f MLP) with a rise in the intracellular calcium concentration ([Ca²]_i), NADPH oxidase activation, and increased superoxide anion (O₂⁻) production. [Ca²⁺]_imobilization and superoxide production were largely dependent on extracellular calcium (Ca²⁺]_e) and a capacitative calcium entry. The monomeric G-protein, Rac-1, regulates NADPH oxidase activity. We tested the effect of removal of Ca²⁺]_eon Rac-1 plasma membrane sequestration and activation of NADPH oxidase using immunodetection and a double labelling fluorescent method. Results showed that Rac-1 activation is mediated via a pertussis toxin (PTX)-sensitive heteromeric G-protein pathway, and that Rac-1 membrane sequestration was preceded by [Ca²⁺]_imobilization following entry of Ca²⁺_e. Therefore, we propose that O₂⁻production is dependent on activation of PTX-sensitive G-proteins and sequestration of Rac-1 in the plasma membrane, following entry of Ca²⁺_e.     

Leaf chlorophyll fluorescence, reflectance, and physiological response to freshwater and saltwater flooding in the evergreen shrub, Myrica cerifera

Photosynthesis, water relations, chlorophyll fluorescence, and leaf reflectance were used to evaluate stress due to freshwater and saltwater flooding in the evergreen coastal shrub, Myrica cerifera, under controlled conditions. M. cerifera forms large monospecific thickets that facilitate scaling up from leaf-level measurements to the landscape. Based on physiological responses, stress began by day 3 in flooded plants treated with 5, 10, and 15 g L⁻¹ salinity, as seen by significant decreases in stomatal conductance and net photosynthesis relative to control plants. Decreases in physiological measurements occurred by day 9 in freshwater flooded plants. Visible signs of stress occurred by day 5 for plants treated with 15 g L⁻¹, day 8 for flooded plants exposed to 10 g L⁻¹, and day 10 for those treated with 5 g L⁻¹ salinity. Significant differences in light-adapted fluorescence yield () were observed by day 3 in plants flooded with 5, 10, and 15 g L⁻¹ salinity and day 6 in freshwater flooded plants. Non-photochemical quenching (Φ_NPQ) increased with decreasing . In comparison, statistical differences in dark-adapted fluorescence yield (F_v/F_m) were observed by day 12 in plants flooded with 5, 10, and 15 g L⁻¹ salinity, well after visible signs of stress were apparent. Fluorescence parameters were successful at detecting and distinguishing both freshwater and saltwater flooding stress. A positive, linear correlation (r² = 0.80) was observed between and the physiological reflectance index (PRI). Xanthophyll-cycle dependent energy dissipation appears to be the underlying mechanism in protecting photosystem II from excess energy in saltwater flooded plants. was useful in detecting stress-induced changes in the photosystem before any visible signs of damage were evident at the leaf-level. This parameter may be linked to hyperspectral reflectance data for rapid detection of stress at the canopy-level.     

NO detection in biological samples: Differentiation of NO and NO using infrared laser spectroscopy

Accurate characterization of the biochemical pathways of nitric oxide (NO) is essential for investigations in the field of NO research. To analyze the different reaction pathways of enzymatic and non-enzymatic NO formation, determination of the source of NO is crucial. Measuring NO-related products in biological samples distinguishing between ¹⁴NO and ¹⁵NO offers the opportunity to specifically analyze NO signaling in blood and tissue. The aim of this study was to establish a highly sensitive technique for the specific measurement of NO in an isotopologue-selective manner in biological samples.With the cavity leak-out spectroscopy setup (CALOS) a differentiation between ¹⁴NO and ¹⁵NO is feasible. We describe here the employment of this method for measurements in biological samples. Certified gas mixtures of ¹⁴NO/N₂ and ¹⁵NO/N₂ were used to calibrate the system. and of aqueous and biological samples were reduced in a triiodide solution, and the NO released was detected via CALOS. Gas-phase chemiluminescence detection (CLD) was used for evaluation.The correlation received for both methods for the detection of NO in the gas phase was r = 0.999, p < 0.0001. Results obtained using aqueous and biological samples verified that CALOS enables NO measurements with high accuracy (detection limit for 0.3 pmol and 0.5 pmol; correlation ¹⁴NO: p < 0.0001, r = 0.975, ¹⁵NO: p < 0.0001, r = 0.969).The CALOS assay represents an extension of NO measurements in biological samples, allowing specific investigations of enzymatic and non-enzymatic NO formation and metabolism in a variety of samples.     

High-performance liquid chromatographic–fluorimetric assay of chymotrypsin-like esterase activity

A sensitive and reproducible assay for the determination of chymotrypsin-like esterase activity is reported. This method is based on fluorimetric detection of a dansylated amino acid, 5-dimethylaminonaphthalene-1-sulfonyl- -phenylalanine, enzymatically formed from the substrate 5-dimethylaminonaphthalene-1-sulfonyl- -phenylalanine ethyl ester, after separation by high-performance liquid chromatography using a C₁₈ reversed-phase column and isocratic elution. This method is sensitive enough to measure 5-dimethylaminonaphthalene-1-sulfonyl- -phenylalanine at concentrations as low as 40 pmol/ml, yields highly reproducible results and requires less than 9.5 min per sample for quantitation. The optimum pH for chymotrypsin-like esterase activity was 7.7–8.3. The K_m and V_max values were, respectively 25 μM and 0.241 pmol/μg protein/h with the use of enzyme extract obtained from mouse kidney. The approximate molecular mass of this enzyme was estimated to be 67 000 by gel filtration. Chymotrypsin-like esterase activity was strongly inhibited by N-tosyl- -phenylalaline chloromethyl ketone. Among the mouse organs examined, the highest specific activity of the enzyme was found in lung. This new method would be useful for clarification of the physiological role of this enzyme.     

Effects of the New Arginase Inhibitor N-Hydroxy-nor- -Arginine on NO Synthase Activity in Murine Macrophages

In stimulated murine macrophage, arginase and nitric oxide synthase (NOS) compete for their common substrate, -arginine. The objectives of this study were (i) to test the new α-amino acid N^ω-hydroxy-nor- -arginine (nor-NOHA) as a new selective arginase inhibitor and (ii) to elucidate the effects of arginase inhibition on -arginine utilization by an inducible NOS. Nor-NOHA is about 40-fold more potent than N^ω-hydroxy- -arginine (NOHA), an intermediate in the -arginine/NO pathway, to inhibit the hydrolysis of -arginine to -ornithine catalyzed by unstimulated murine macrophages (IC₅₀ values 12 ± 5 and 400 ± 50 μM, respectively). Stimulation of murine macrophages with interferon-γ and lipopolysaccharide (IFN-γ + LPS) results in clear expression of an inducible NOS (iNOS) and to an increase in arginase activity. Nor-NOHA is also a potent inhibitor of arginase in IFN-γ + LPS-stimulated macrophage (IC₅₀ value 10 ± 3 μM). In contrast to NOHA, nor-NOHA is neither a substrate nor an inhibitor for iNOS and it appears as a useful tool to study the interplays between arginase and NOS. Inhibition of arginase by nor-NOHA increases nitrite and -citrulline accumulation for incubation times higher than 12 h, under our conditions. Our results allow the determination of the kinetic parameters of the two competitive pathways and the proposal of a simple model which readily explains the differences observed between experiments. This model readily accounts for the observed effects and should be useful to predict the consequences of arginase inhibition in the presence of an active NOS on -arginine availability.     

New cell wall glycopolymers of the representatives of the genus Kribbella

Each of the cell walls of four representatives of the genus Kribbella (order Actinomycetales; suborder Propionibacterineae; family Nocardioidaceae) contains a neutral polysaccharide and an acidic polysaccharide with unusual structures. Common to all four strains studied is a mannan with the following repeating unit: In the cell wall of the strain VKM Ac-2541, a teichulosonic acid was identified with a monosaccharide component that has not hitherto been found in Gram-positive bacteria, viz., pseudaminic acid, and an unusual linkage type in the polymeric chain,

Full-size image (1K)

where R = Н (45%), α-d-Galp3OMe (37%) or α-d-Galp2,3OMe (18%).The anionic cell wall components of three other strains are represented by teichuronic acids with a rare constituent, viz., a diaminosugar, 2,3-diacetamido-2,3-dideoxyglucopyranose. The structures of their repeating units differ in the nature of the acidic components:→4)-β-d-Manp2,3NAcA-(1→6)-α-d-Glcp2,3NAc-(1→ (VKM Ас-2538 and VKM Ас-2540) and →4)-β-d-ManpNAcA-(1→6)-α-d-Glcp2,3NAc-(1→ (VKM Ас-2539).The structures of all the glycopolymers were established by chemical and NMR spectroscopic methods; they are identified in Gram-positive bacteria for the first time.     

An antitumor promoter from Moringa oleifera Lam.

In the course of studies on the isolation of bioactive compounds from Philippine plants, the seeds of Moringa oleifera Lam. were examined and from the ethanol extract were isolated the new O-ethyl-4-(α- -rhamnosyloxy)benzyl carbamate (1) together with seven known compounds, 4(α- -rhamnosyloxy)-benzyl isothiocyanate (2), niazimicin (3), niazirin (4), β-sitosterol (5), glycerol-1-(9-octadecanoate) (6), 3-O-(6′-O-oleoyl-β- -glucopyranosyl)-β-sitosterol (7), and β-sitosterol-3-O-β- -glucopyranoside (8). Four of the isolates (2, 3, 7, and 8), which were obtained in relatively good yields, were tested for their potential antitumor promoting activity using an in vitro assay which tested their inhibitory effects on Epstein–Barr virus-early antigen (EBV-EA) activation in Raji cells induced by the tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). All the tested compounds showed inhibitory activity against EBV-EA activation, with compounds 2, 3 and 8 having shown very significant activities. Based on the in vitro results, niazimicin (3) was further subjected to in vivo test and found to have potent antitumor promoting activity in the two-stage carcinogenesis in mouse skin using 7,12-dimethylbenz(a)anthracene (DMBA) as initiator and TPA as tumor promoter. From these results, niazimicin (3) is proposed to be a potent chemo-preventive agent in chemical carcinogenesis.     

Chaperone-Assisted Overexpression of an Active -Carbamoylase from Agrobacterium tumefaciens AM 10

The N-carbamoyl- -amino acid amidohydrolase ( -carbamoylase) gene (dcb) from Agrobacterium tumefaciens AM 10 was cloned by polymerase chain reaction in plasmid pET28a and was overexpressed in Escherichia coli JM109 (DE3). However, almost 80% of the enzyme remained trapped in inclusion bodies. To facilitate the expression of the properly folded active enzyme, the chaperones GroEL/ES were coexpressed in plasmid pKY206. This resulted in a 43-fold increase in active enzyme production compared to the wild-type strain. The histidyl-tagged -carbamoylase was purified by a single step nickel-affinity chromatography to a specific activity of 9.5 U/mg protein.     

N-acetyl- -arginine ethyl ester synthesis catalysed by bovine trypsin in organic media

The bovine trypsin-catalysed synthesis of N-acetyl- -arginine ethyl ester from N-acetyl- -arginine and ethanol was studied in various organic solvents (dimethyl sulfoxide, dioxane, dimethylformamide, acetonitrile, acetone, tetrahydrofuran, chloroform, toluene, carbon tetrachloride, cyclohexane and n-hexane). The highest yield was achieved in acetonitrile after incubation for 6 or 24 h. The optimal conditions for ester synthesis in acetonitrile for 6 h were as follows: 5.0 mM N-acetyl- -arginine, 10.0 M ethanol, 7.2 mg trypsin, 2.87% water, total volume 10.3 ml, pH 7.0 and 30°C. The hydrolytic activity of trypsin was determined after incubation for 6 days, when 87.7% of the original activity remained, suggesting that acetonitrile caused little inactivation of the enzyme. The synthetic reaction resulted in a maximal 79.3% conversion under optimized conditions after incubation for 48 h.     

Physicochemical properties and antitumor activities for sulfated derivatives of lentinan

Five fractions of lentinan, a β-(1→3)-d-glucan bearing β-(1→6)-d-glucopyranosyl branches, were treated with chlorosulfonic acid for 90 min at 60 °C in pyridine medium to synthesize water-soluble sulfated derivatives having the substitution degree of 1.44–1.76. The ¹³C NMR spectra of the sulfated β-glucans indicated that the C-6 position was preferentially substituted by the sulfate groups. The values of the weight-average molecular weight (M_w), radius of gyration (), and intrinsic viscosity ([η]) of the sulfated lentinan fractions were determined by size-exclusion chromatography with multi-angle laser light scattering (SEC–MALLS) and viscometry in 0.15 M aq NaCl at 25 °C, respectively. The dependence of [η] on M_w for the sulfated lentinan was found to be [η] = 8.93 × 10⁻³ (mL/g) in 0.15 M aq NaCl (for M_w ranging from 14.6 × 10⁴ to 50.4 × 10⁴). On the basis of the Yamakawa–Fujii–Yoshizaki (YFY) theory, the conformational parameters of the sulfated lentinan were calculated as 950 nm⁻¹ for the molar mass per unit contour length (M_L), 4.8 nm for the persistence length (q), and 13.9 for the characteristic ratio (C_∞), indicating relatively extended single flexible chains in solution. The sulfated glucan fractions exhibited in vitro antiproliferative activities against sarcoma 180 (S-180) cells, and their inhibition ratios were lower than that of the triple-helix lentinan, but higher than that for the one with single random-coil lentinan chains.     

Forest structure of a subtropical mangrove along a river inferred from potential tree height and biomass

The hypothesis was tested that potential tree height and biomass in mangroves decrease downstream with the tidal gradient along the Okukubi River in Okinawa Island, Japan. The mangrove stands consisted of Bruguiera gymnorrhiza (L.) Lamk. and Kandelia obovata (S., L.) Yong (Rhizophoraceae). Four sites were selected considering the distance from the mouth of the river. Soil salinity increased downstream, while soil total nitrogen content decreased. The soil redox potential did not vary along the river. Maximum gross photosynthesis and tree height for each species decreased downstream. The potential tree height (H_max) inferred from the stem diameter (D_0.1)–tree height (H) relationship ( a, h, coefficient) in each species decreased downstream. The tree density (ρ)–mean tree size () relationships ( K, α, coefficient) determined for four sites revealed that the mean tree size at any given tree density decreased downstream, which indicates the decrease of potential biomass. Furthermore, an index for biomass () was homogeneous within a site regardless of tree density, i.e. the value of α at each site did not differ significantly from 1.0 (p > 0.05). The decreases in potential tree height and biomass may be partially ascribed to the stressful environments at the downstream sites characterized by high salinity (>2.6%) and nitrogen-poor soils (<0.25 ppt) in our study area.     

Testing German shepherd puppies to assess their chances of certification

Behavioral activity of 7-week-old German shepherd puppies was tested and the activities analyzed if they could be used for predicting police efficiency of the individual. In total 206 individuals sired by 42 sires and 44 dams were used. The activities were divided into 10 tasks in which reactions and behavior of pups were scored from 0 to 5 points. All pups were tested separately from other conspecifics. Probability that the puppy will pass the certification was tested by a logistic regression. Of the 206 puppies, 148 passed the certification while 58 failed. Some tested behavioral variables were moderately to highly correlated with one another. Therefore we applied a factor analysis. Three factors were retained accounting for 100% of the shared variance. After inspection of the rotated factor pattern matrix and its confidence intervals, it appeared that variables “Independent movement and interactions with the tester”, “Negotiating obstacles”, “Entering a room”, “Behavior toward a person”, and “Behavior in new environments” loaded on Factor 1 (“Factor for movement”), while variables “Response to distracting stimuli caused by a shovel”, “Response to a distracting noise while left alone in a room”, and “Response to loud distracting stimuli” on Factor 2 (“Factor for responding to noise”) and variables “Retrieval” and “Tug of war” on Factor 3 (“Factor for attitude to predation”). In the final logistic regression model, the probability that the puppy will pass the certification depended on the higher weight at the time of testing (, P = 0.0005), on the “Factor for attitude to predation” (, P = 0.0007), on the “Factor for responding to noise”, where the higher the score, the weaker was the response (, P = 0.0232), and on the “Factor for movement” showing an increasing probability with decreasing score (, P = 0.0219). The tests in our study seem to be a good base which might enable selection for suitable dogs as early as 7 weeks of age. The puppies having high probability to pass certification in adulthood were heavy individuals willing to chase, catch, and fetch a tennis ball, and follow a rag drawn away from them, while weakly responding to a distracting noise in various situations and showing low activity while negotiating obstacles and moving and interacting with the tester. To conclude, contrary to skeptical assumptions expressed by various authors, the specific puppy tests for police dogs provide a reliable tool for predicting future service ability of a puppy. Differences in methodology are likely to contribute to a lack of consensus among various studies.     

Kinetic and thermodynamic characterization of the cold activity acquired upon single amino-acid substitution near the active site of a thermostable α-glucosidase

The α-glucosidase of Bacillus sp. SAM1606, a thermophilic bacterium, is a thermostable enzyme that has maximal activity at an apparent optimal temperature between 65 and 70 °C and only very low activity at low temperatures (0–25 °C). In this study, we identified Thr272, which is located adjacent to Glu271 (a catalytic residue) and Gly273 (a determinant of specificity), as a determinant of the optimal temperature, as substitution of Thr272 with other residues significantly altered the temperature–activity profile of the enzyme. Substitution of Thr272 with other amino acids, in particular bulky hydrophobic residues such as valine, methionine and phenylalanine, resulted in a significant downward shift (by 30 °C) of the apparent optimal temperature with an increase in catalytic activity at low temperatures. The observed downward shift of the apparent optimal temperature was not due to instability of the mutants at 40–65 °C, as the mutants were stable at temperatures up to 65 °C. Among the mutants examined, T272V displayed the highest k_cat values at 10–25 °C, which was at least 11-fold greater than the k_cat value observed for the wild-type enzyme. The thermodynamic characteristics of reactions catalyzed by T272V, T272M, T272F, and wild type at 25 °C were examined in greater detail. The T272V, T272M and T272F mutants displayed large K_s (or K_m) values and reduced and values at 25 °C, consistent with the general features of cold adaptation. The observed cold activities of T272V, T272M and T272F most likely arose from local flexibility of the active site at low temperatures due to loss of a Thr272-mediated hydrogen bond. However, this hydrogen-bond loss likely permits reversible conformational changes of the active site to less active forms at elevated temperatures (e.g., 60 °C). This may explain why catalytic activities for T272V, T272M and T272F at high temperatures (e.g., 60 °C) were lower than those at low temperature (e.g., 25 °C), even though the mutant enzymes appeared stable at 60 °C.     

Green liquor dregs effect on Kraft mill secondary sludge composting

Increased Kraft pulp mill production generates increased solid wastes. In response, composting has emerged as an interesting alternative for disposal of these solid wastes.A central composite factor design was used to investigate the influence of incubation conditions (dregs addition and operation time) on chemical and biological parameters, determining the best in-vessel conditions in order to develop a correct composting design.Dregs helped reduce the pH drop that occurs at the beginning of the process. Biological activities presented high values during the active phase, followed by a decrease with stable final values along with N– and N– trend, which were indicative of mature compost.Dregs addition had not significant effect on the biological activities during composting of Kraft mill sludge. However, moderate amounts of dregs (between 5% and 8%) at operation time of 60–70 days would be the best compromise.     

Further mechanistic orientation for the oxidation reaction between alkaline permanganate and poly galacturonate methyl ester. Novel spectrophotometric tracer of intrahypomanganate(V) – Intermediate

The kinetics of formation of the green manganate(VI) intermediate complex formed during the oxidation of pectin polysaccharide (poly galacturonate methyl ester) (PGME) by in alkaline solution at pH  12 have been studied. The rate law was suggested to be: rate = . The reaction was found to be base – catalyzed and fractional second – order in [PGME]. The activation parameters have been evaluated and discussed. A reaction mechanism was suggested according to the experimental data. A new blue hypomanganate(V) coordination polymer intermediate sol was spectrophotometrically detected for the first time for pectin (poly galacturonate methyl ester) oxidation reaction. A further mechanistic presentation was proposed.     

Chain conformation of carboxymethylated derivatives of (1 → 3)-β-d-glucan from Poria cocos sclerotium

A water-insoluble (1 → 3)-β-d-glucan (PCSG) isolated from the fresh sclerotium of Poria cocos was carboxymethylated to afford a water-soluble derivative coded as C-PCSG. The carboxymethylated (1 → 3)-β-d-glucan was fractionated to obtain eight fractions according to the nonsolvent addition method. The weight-average molecular mass (M_w), radius of gyration and intrinsic viscosity ([η]) of the fractions were determined by size-exclusion chromatography combined with laser light scattering (SEC-LLS) and viscometry in 0.2 M NaCl aqueous solution at 25 °C. The dependences of [η] and on M_w for C-PCSG were found to be , and (nm), respectively. Analysis of M_w and [η] in terms of the known theories for wormlike chain model yielded 633 nm⁻¹ for molar mass per unit contour length (M_L), 5.5 nm for persistence length (q), and 20.2 for characteristic ratio (C_∞). These results indicated that C-PCSG exists as a relatively extended flexible chain in 0.2 M NaCl aqueous solution. Therefore, the introduction of the carboxymethyl groups into the β-glucan improved significantly the water solubility and enhanced the stiffness of the chains.