Aspercitrininone A, novel antibacterial polyketide featuring unusual spiral skeleton from Aspergillus cristatus.

Aspercitrininone A (1), a novel polyketide featuring an unprecedented tetracyclic 6/6/6/5 spiral skeleton, was obtained from the rice fermentation cultures of the fungus Aspergillus cristatus together with five known compounds (2-6). Their structures were determined by HRESIMS data, 1D and 2D NMR spectroscopic analysis, and electronic circular dichroism (ECD) calculations. Aspercitrininone A was revealed as a new type of C/D cycle spiral structure and an unusual addition product of o-quinoid form citrinin with 2-methylterrefuranone. Compounds 1, 4, and 5 exhibited potent antibacterial activities with minimal inhibitory concentration (MIC) values from 13.2 to 67.3 µg/mL against four strains of human pathogenic bacteria in vitro.

Antibacterial metabolites from the beetle-associated fungus Penicillium chrysogenum.

The antibacterial secondary metabolites of the fungus Penicillium chrysogenum associated with the beetle Aspongopus chinensis were investigated through chromatographic fractionation methods of ethyl acetate extracts of the fungal cultures. Five compounds were isolated, and their structures were determined as emodin, 4-(methoxymethyl)benzoic acid, isoochracinic acid, secalonic acid D, and dicerandrol A using mass spectroscopy and nuclear magnetic resonance spectroscopic analyses. Emodin exhibited strong antimicrobial activity, especially against Staphylococcus aureus even when growing on cooked pork, with a minimal inhibitory concentration (MIC) of 6.3 µg/mL. Dimeric tetrahydroxanthones, such as secalonic acid D and dicerandrol A, also exhibited potent activity, with MIC values ranging from 9.5 to 28.5 µg/mL. In summary, P. chrysogenum was isolated as a symbiotic fungus of the beetle A. chinensis for the first time and this strain could generate antibacterial secondary metabolites, which could potently inhibit gram-positive bacteria growth in vitro.

Antibacterial and antioxidant metabolites from the insect-associated fungus Aspergillus fumigatus.

The research on bioactive secondary metabolites from Aspergillus fumigatus afforded six compounds, which were identified by mass spectrometer (MS) and nuclear magnetic resonance (NMR) spectroscopic analysis as cyclopyazonic acid (1), trypacidin A (2), asterric acid (3), methyl asterrate (4), demethylcitreoviranol (5), as well as (5-hydroxy-2-oxo-2H-pyran-4-yl) methyl acetate (6). Cyclopyazonic acid (1) was found to have potent antibacterial effects, especially against Bacillus licheniformis with minimal inhibitory concentration (MIC) value of 3.7µg/mL. Its antibacterial effects were possibly related to the olefinic acid group in the structure. Phenyl ether derivatives 3 and 4, and trypacidin A (2) also exhibited antimicrobial effects. In addition, compound 6 showed significant antioxidant effects with half maximal effective concentration (EC50) value of 10.2µM in the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) assay, which was better than the positive control.

Novel kojic acid derivatives with anti-inflammatory effects from Aspergillus versicolor.

Two novel kojic acid derivatives, kojicones A and B (1 and 2), along with the precursors kojic acid (3) and (2R,4R)-4-hydroxy-5-methoxy-2,4-dimethyl-2- [(2R)-2-methylbutyryloxy]-5-cyclohexen-1,3-dione (4), were isolated from a fungal strain Aspergillus versicolor. Their structures and absolute configurations were accurately confirmed by HRESIMS data, NMR analysis, and electronic circular dichroism (ECD) calculations. Kojicones A and B were the first examples of kojic acid adducts with cyclohexen-1,3-dione possessing unprecedented tricycle skeletons. Compounds 1-3 were found to have inhibition on the NO production of murine RAW 264.7 cells. They can also reduce the mRNA expression of four cytokines (IL-6, IL-1ß, TNF-α, and iNOS) and promote the expression of IL-4 at 20 µM. Moreover, kojic acid (3) could treat the DSS (dextran sulfate sodium)-induced colitis on mice with the effectiveness similar to that of the positive control. The results suggested that kojic acid and its derivatives could be a promising anti-inflammatory source for the medicinal and cosmetic industry.

Antioxidant epoxydon and benzolactone derivatives from the insect-associated fungus Phoma sp.

One new epoxydon ester (1) and a new benzolactone derivative (2), along with four known compounds (3-6), were isolated from the insect-associated fungus Phoma sp. Their structures were confirmed by extensive MS and NMR spectroscopic analysis and their absolute configurations were determined by a combination of modified Mosher method and Mo2(OCOCH3)4-induced electronic circular dichroism (ECD) experiments. Compounds 1 and 5 were revealed to have potent antioxidant activities, which were approximate to the potency of the positive control trolox. In addition, 1 also exhibited moderate cytotoxic effect against human MGC-803 tumor cell line.[Formula: see text].

Antioxidant coumarin and pyrone derivatives from the insect-associated fungus Aspergillus Versicolor.

Two new compounds, versicolones A and B (1 and 2), and three known pyrone derivatives (3-5) were isolated from the insect-associated fungus Aspergillus versicolor. Their structures were elucidated through a combination of HRESIMS and NMR spectroscopic analysis. Versicolone A (1) was revealed as a coumarin derivative with the rare 5-alkyl side chain substitution. Compound 5 exhibited significant antioxidant activity with EC50 value of 8.0 µM in the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) assay, which was more than 2-fold potency of the positive control trolox.

Antifungal Macrocyclic Trichothecenes from the Insect-Associated Fungus Myrothecium roridum.

Three new macrocyclic trichothecenes possessing rare 6'-ketal moieties, roridoxins A-C (1-3), and five known compounds (4-8) were isolated from the insect-associated fungus Myrothecium roridum. Their structures were confirmed by a combination of NMR and HRESIMS data, while their absolute configurations were unambiguously determined by single-crystal X-ray analysis and electronic circular dichroism experiments. Trichothecenes 1 and 3 showed potent antifungal activities against four strains of phytopathogenic fungi. In addition, 1, 3, 5, and 6 were found to significantly inhibit the cell growth of Candida albicans with minimal inhibitory concentration values from 8.8 to 18.5 µg/mL. Moreover, they were able to inhibit the biofilm formation of C. albicans better than the positive control.

Optimization of exopolysaccharide production in submerged culture of Daedalea dickinsii and its antioxidant activity.

The major nutrients, pH and temperature were evaluated for the exopolysaccharide (EPS) production by Daedalea dickinsii in submerged culture to derive an optimal medium composition and conditions as follows: 50 g/L maltose, 5 g/L soy peptone, 5 mM CaCl(2), at pH 6.0 and 28 °C. A purified EPS fraction was attained from gel filtration chromatography and its major molecular characteristics were determined. FT-IR spectral analysis revealed the prominent characteristic groups of polyhydric alcohols. GC analysis and NMR spectrum showed its major molecular composition of glucose and galactose. Furthermore, thermogravimetric analysis indicated its degradation temperature (T(d)) of 189 °C. The antioxidant activity of the EPS fraction showed a correlation with the molecular properties. It might be attributed to the functional groups in the EPS fraction, which can donate electrons to reduce the radicals to a more stable form or react with the free radicals to terminate the radical chain reaction.

[Effects of hemoperfusion on the patients with acute toxication of 2, 4-dinitrophenol].

OBJECTIVE: To explore the management strategies of acute toxication of 2, 4-dinitrophenol by hemoperfusion. METHODS: A total of 14 patients with acute toxication of 2, 4-dinitrophenol were admitted on September 14, 2009. And they were divided into severe and mild groups according to the severity of clinical manifestation. All patients in both groups received 2-hour blood perfusion within 2 hour post-admission. Their clinical manifestations, laboratory parameters and 2, 4-dinitrophenol levels were carefully observed before and after each perfusion. And oxygenation, intravenous use of furosemide, corticosteroids and symptomatic therapies were simultaneously given to improve general conditions. RESULTS: In serious group, the levels of before and after the first perfusion were 28.21(15.56-45.23) and 16.11(10.10-27.52) mg/L (P < 0.05), respectively. In both groups, all levels of 2, 4-dinitrophenol were significantly reduced before and after each perfusion (all P < 0.05). The patients in severe group would get relieved after 3 vs 2 perfusions in mild group. In severe group, there was a remarked decrease in neutrophil and platelet count after perfusion than those in mild group. The liver enzymes and blood lipids in both groups after therapy significantly elevated than those before therapy (all P < 0.05). CONCLUSION: Crucial for managing acute toxication of 2, 4-dinitrophenol, early hemoperfusion reduces mortality.

Antioxidant activity potential of Virginia (flue-cured) tobacco flower polysaccharide fractions obtained by ultrasound-assisted extraction.

Ultrasound-assisted extraction was employed to extract polysaccharide from Virginia (flue-cured) tobacco flowers. The orthogonal matrix method (L9(3)(4)) was used to determine the optimal extraction conditions as to ultrasound power, extraction time, ratio of solvent to solid, and extraction temperature at 300 W, 4 min, 35 (mL/g), and 70 °C respectively. The crude extract was successively purified by chromatography, yielding two major polysaccharide fractions, termed Fr-I and Fr-II. Both fractions are heteropolysaccharides, mainly containing glucose, mannose, and allose with an a-configuration. Thermo gravimetric analysis (TGA) indicated that the degradation temperatures (Td) of Fr-I and Fr-II were 185 °C and 190 °C respectively. The preliminary antioxidant activity test in vitro showed both fractions could potentialize the scavenging effect on hydroxyl and DPPH radicals in a dose-dependent manner. In conclusion, the two polysaccharides may be useful as naturally potential antioxidant agents for application in food and medicinal fields.

Production, purfication, molecular characterization and bioactivities of exopolysaccharides produced by the wine cap culinary-medicinal mushroom, Stropharia rugosoannulata 2# (higher Basidiomycetes).

The optimal culture conditions of exopolysaccharides (EPS) production in submerged culture medium by Stropharia rugosoannulata 2# were determined using the orthogonal matrix method. The optimal defined medium (per liter) was 60.0 g sucrose, 6.0 g tryptone, 5 mM KH2PO4, and initial pH 7.0 at 28°C. In the optimal culture medium, the maximum EPS production was 9.967 g/L in shake-flask culture. One fraction of EPS was purified from the culture filtrates by size exclusion chromatography (SEC), and the molecular characteristics were examined by a multiangle laser-light scattering (MALLS) and refractive index (RI) detector system. The weight-average molar masses and the polydispersity ratio of the EPS fraction were determined to be 5.305 × 103 g/mol and 2.014, respectively. FTIR spectroscopy was used for obtaining vibrational spectra of the purified EPS fraction. The obvious characteristic absorption at 884.3 cm-1 revealed the existence of ß configuration. Furthermore, the experiments in vitro indicated that S. rugosoannulata 2# EPS exhibit high antitumor and antioxidative effects.

Staphylococcus aureus-fibronectin interactions with and without fibronectin-binding proteins and their role in adhesion and desorption.

Adhesion and residence-time-dependent desorption of two Staphylococcus aureus strains with and without fibronectin (Fn) binding proteins (FnBPs) on Fn-coated glass were compared under flow conditions. To obtain a better understanding of the role of Fn-FnBP binding, the adsorption enthalpies of Fn with staphylococcal cell surfaces were determined using isothermal titration calorimetry (ITC). Interaction forces between staphylococci and Fn coatings were measured using atomic force microscopy (AFM). The strain with FnBPs adhered faster and initially stronger to an Fn coating than the strain without FnBPs, and its Fn adsorption enthalpies were higher. The initial desorption was high for both strains but decreased substantially within 2 s. These time scales of staphylococcal bond ageing were confirmed by AFM adhesion force measurement. After exposure of either Fn coating or staphylococcal cell surfaces to bovine serum albumin (BSA), the adhesion of both strains to Fn coatings was reduced, suggesting that BSA suppresses not only nonspecific but also specific Fn-FnBP interactions. Adhesion forces and adsorption enthalpies were only slightly affected by BSA adsorption. This implies that under the mild contact conditions of convective diffusion in a flow chamber, adsorbed BSA prevents specific interactions but does allow forced Fn-FnBP binding during AFM or stirring in ITC. The bond strength energies calculated from retraction force-distance curves from AFM were orders of magnitude higher than those calculated from desorption data, confirming that a penetrating Fn-coated AFM tip probes multiple adhesins in the outermost cell surface that remain hidden during mild landing of an organism on an Fn-coated substratum, like that during convective diffusional flow.

Interaction forces between salivary proteins and Streptococcus mutans with and without antigen I/II.

The antigen I/II family of surface proteins is expressed by oral streptococci, including Streptococcus mutans, and mediates specific binding to, among others, salivary films. The aim of this study was to investigate the interaction forces between salivary proteins and S. mutans with (LT11) and without (IB03987) antigen I/II through atomic force microscopy (AFM) and to relate these interaction forces with the adhesion of the strains to saliva-coated glass in a parallel plate flow chamber. Upon approach of the bacteria toward a saliva-coated AFM tip, both strains experienced a similar repulsive force that was significantly smaller at pH 6.8 (median 3.0 and 3.1 nN for LT11 and IB03987, respectively) than at pH 5.8 (median 4.6 and 4.7 nN). The decay length of these repulsive forces was between 19 and 37 nm. Upon retraction at pH 6.8, the combined specific and nonspecific adhesion forces were significantly stronger for the parent strain LT11 (median -0.4 nN) than for the mutant strain IB03987 (median 0.0 nN), whereas at pH 5.8 the median of the adhesion forces measured was 0.0 nN for both strains. Moreover, at pH 6.8, the parent strain LT11 adhered in significantly higher numbers (9.6 x 106 cm-2) to a salivary coating than the mutant strain IB03987 (2.5 x 106 cm-2). Similar to the difference in adhesion forces between both strains at pH 5.8, the difference in adhesion between both strains also disappeared at pH 5.8, which suggests the involvement of attractive electrostatic forces in the interaction between antigen I/II and salivary coatings. In summary, this study shows that antigen I/II at the surface of S. mutans LT11 is responsible for its increased adhesion to salivary coatings under flow through an additional attractive electrostatic force.

[Expression of nuclear transcription factor kappaB in childhood acute lymphoblastic leukemia and its significance].

To investigate the expression of nuclear transcription factor kappaB (NF-kappaB) in childhood acute lymphoblastic leukemia (ALL) and its significance, the biotin-streptavidin method and microscopy were used to detect NF-kappaB P65 protein in cells from 32 childhood ALL patients and 40 children without hematologic malignancies as control. The results showed that the positive expression rate of NF-kappaB P65 protein in cells from 32 childhood ALL patients was 87.50%, obviously higher than that in control group (12.50%) (chi(2) = 40.56, p < 0.01). In 28 childhood ALL patients with positive expression, the ratio of weakly positive (+) cases to all positive cases was 10.71% (3/28); the ratio of generally positive (++) case was 42.86% (12/28), and the ratio of strongly positive (+++) cases was 46.43% (13/28). While in the control group the of NF-kappaB P65 protein showed low expression with 100% (5/5). There was significant difference in the level of NF-kappaB P65 protein between ALL patients and control group. While the level of NF-kappaB P65 protein had no significent difference in morphology, immunophenotype (T-lineage ALL and B-lineage ALL) and the courses in the de novo and the relaspsed cases. It is concluded that NF-kappaB P65 protein expresses in cells of childhood ALL, the inhibition of NF-kappaB transduction pathway may have significant value in childhood ALL treatment. This study provides experimental basis concerning clinical treatment for ALL, when NF-kappaB is taken as a target.

Calorimetric comparison of the interactions between salivary proteins and Streptococcus mutans with and without antigen I/II.

Antigen I/II can be found on streptococcal cell surfaces and is involved in their interaction with salivary proteins. In this paper, we determine the adsorption enthalpies of salivary proteins to Streptococcus mutans LT11 and S. mutans IB03987 with and without antigen I/II, respectively, using isothermal titration calorimetry. In addition, protein adsorption to the cell surfaces was determined spectrophotometrically. S. mutans LT11 with antigen I/II, yielded a much higher, exothermic adsorption enthalpy at pH 6.8 (ranging from -2073 x 10(-9) to -31707 x 10(-9) microJ per bacterium) when mixed with saliva than did S. mutans IB03987 (-165 x 10(-9) to -1107 x 10(-9) microJ per bacterium) at all bacterial concentrations studied (5 x 10(9), 5 x 10(8), and 5 x 10(7) ml(-1)), largest effects per bacterium being observed for the lowest concentration. However, the enthalpy of salivary protein adsorption to S. mutans LT11 became smaller at pH 5.8. Adsorption isotherms for the S. mutans LT11 showed considerable protein adsorption at pH 6.8 (1.2 - 2.1 mg/m(2)), that decreased only slightly at pH 5.8 (1.1 - 1.6 mg/m(2)), with the largest amount adsorbed at the lowest bacterial concentration. This suggests that the protein(s) in the saliva with the strongest affinity for antigen I/II is (are) readily depleted from saliva. In conclusion, antigen I/II surface proteins on S. mutans play a determinant role in adsorption of salivary proteins through the creation of enthalpically favorable adsorption sites.

Optimization of physical parameters for exo-biopolymer production in submerged mycelial cultures of two entomopathogenic fungi Paecilomyces japonica and Paecilomyces tenuipes.

AIMS: In the present study, two different optimization techniques were used to determine the suitable operating parameters for exo-biopolymer production in submerged mycelial cultures of two entomopathogenic fungi Paecilomyces japonica and Paecilomyces tenuipes. METHODS AND RESULTS: First, the rotating simplex method, a nonstatistical optimization technique, was employed to obtain the best combination of physical parameters (viz. pH, agitation intensity, aeration rate) for maximum exo-biopolymer production by P. japonica in a batch bioreactor. The optimal combination was determined to be a pH of 8.06, an aeration of 3 vvm, without any impeller agitation, producing a 17-time increase in exopolymer production (34.5 g l(-1)) when compared with that achieved in unoptimized flask cultures. Second, the uniform design method, a statistical optimization technique, was employed to determine the best operating parameters for submerged culture of P. tenuipes. The optimal combination for mycelial growth was determined to be a pH of 4.88, an aeration of 2 vvm and an agitation of 350 rpm, while a pH of 4, an aeration of 2 vvm and an agitation of 150 rpm was best for exo-biopolymer production. CONCLUSIONS: The exo-biopolymer production in P. japonica optimized by the rotating simplex method was strikingly improved (max. 34.5 g l(-1)), and the exo-biopolymer production in P. tenuipes optimized by the uniform design method was also significantly increased (max. 3.4 g l(-1)). SIGNIFICANCE AND IMPACT OF THE STUDY: The successful application of these two different optimization techniques in this study implies that these methods are worthy of applying to other fermentation systems for the production of bioactive mycelial biomass and exo-biopolymers in liquid culture of higher fungi.

Production of exopolysaccharides by submerged culture of an enthomopathogenic fungus, Paecilomyces tenuipes C240 in stirred-tank and airlift reactors.

The objective of this study was to investigate the effect of shearing effect on the production of exopolysaccharides (EPS) from an enthomopathogenic fungus, Paecilomyces tenuipes C240 in a stirred-tank reactor (STR) and in an airlift reactor (AR). The optimal agitation rate for the production of EPS in the STR was 150 rpm with the mycelial morphology of hairy pellets, where the final concentration and the specific production rate of EPS were 2.33 g l(-1) and 0.312 gg(-1) h(-1), respectively. However, the maximum concentration of biomass (21.06 g l(-1)) in the STR was obtained at a high agitation speed of 300 rpm. The specific production rate of EPS (0.456 gg(-1) h(-1)) in the AR was significantly higher than that achieved in the STR, in which the typical morphological form of mycelium was a loose clump. The three EPS groups in the STR (designated as STR-I, -II, and -III) and two groups of EPS in the AR (designated as AR-I and -II) were obtained from the culture filtrates by a gel filtration chromatography on Sepharose CL-6B. The molecular weights of STR-I, STR-II, STR-III, AR-I, and AR-II were determined to be 1,820, 25, 1.8, 1,160, and 6.7 kDa, respectively. An agitation rate of 150 rpm in the STR was selected as the optimal culture condition for maximum EPS production (2.33 g l(-1)), which was similar to the level achieved in the AR (2.30 g l(-1)). The carbohydrate composition in each EPS was quite different from each other: the major component was glucose (in STR-I, -III, and AR-I), mannose (in STR-II), and arabinose (in AR-II). In contrast, no significant difference in amino acid composition was observed.

[Anti-pancreatic cancer effects of human peripheral gammadeltaT cells in a mouse tumor model].

OBJECTIVE: To explore the adoptive immunotherapy effect of peripheral gammadeltaT cells in pancreatic cancer nude mice model. METHODS: Thirty BALB/c nude mice were inoculated subcutaneously 5 x 10(5) Cap-1 cells to regularly developed hypodermal tumors, and then divided into 3 groups randomly, gammadeltaT cells, alphabetaT cells and control group. 2.5 x 10(6) gammadeltaT cells or alphabetaT cells or 100 microl RPMI-1640 were respectively injected into abdominal cavity of mice, combined with 10(4) U rhIL-2 for 3 times. Tumor volume, the survival rate and anti-carcinogenic rate of three groups were compared. RESULTS: Eight control nude mice developed hypodermal tumors, which progressively increased in size, and animals had a mean survival of 88 d. Nine nude mice in gammadeltaT cells group and eight in alphabetaT cells group developed tumors (P > 0.05). Tumor growth was arrested and tumor size was reduced remarkably in gammadeltaT cells group. Mean survival was increased to 113 d with less rate of tumor metastasis and more cases of tumor necrosis in gammadeltaT cells group when compared with alphabetaT cells group and controls. CONCLUSIONS: The anti-tumor effects of gammadeltaT cells against pancreatic cancer are better than those of alphabetaT cells and control groups, and might be promising in the adoptive immunotherapy of pancreatic cancer.

Optimization of submerged-culture conditions for mycelial growth and exo-biopolymer production by Auricularia polytricha (wood ears fungus) using the methods of uniform design and regression analysis.

This paper is concerned with the optimization of submerged culture conditions for mycelial growth and exo-biopolymer production by Auricularia polytricha by one-factor-at-a-time and uniform design (UD) methods. First, the one-factor-at-a-time method was adopted to investigate the effects of environmental factors (i.e., initial pH and temperature) and variables of medium components (i.e., carbon, nitrogen and mineral sources) on mycelial growth and exo-biopolymer production. Sucrose, yeast extract, and K2HPO4 were identified to be the most suitable carbon, nitrogen, and mineral sources, respectively. The optimal temperature and initial pH for mycelial growth and exo-biopolymer production were found to be 25 degrees C and 5.0, respectively. Subsequently, the concentrations of sucrose, yeast extract, and K2HPO4 were optimized using the UD method. The optimal concentrations for the enhanced production were determined as 6% (w/v) sucrose, 2.5% (w/v) yeast extract, and 0.3% (w/v) K2HPO4 for mycelial yield, and 6% (w/v) sucrose, 1.28% (w/v) yeast extract, and 0.3% (w/v) K2HPO4 for exo-biopolymer production, respectively. Subsequent experiments confirmed the validity of the models. This optimization strategy in shake-flask culture led to a mycelial yield of 6.14 g/l, and exo-biopolymer production of 2.12 g/l, respectively, which were considerably higher than those obtained in the preliminary studies. By using the optimized medium, the maximum concentrations of mycelial biomass and exo-biopolymer in a 5 litre stirred-tank bioreactor indicated 35.3 g/l and 3.1 g/l, respectively.

Production and characterization of exopolysaccharides from an enthomopathogenic fungus Cordyceps militaris NG3.

Optimization of the submerged culture conditions for the mycelial growth and production of exopolysaccharide (EPS) from a newly isolated Cordyceps species (C. militaris NG3) was studied in flask cultures. The optimal temperature and initial pH for EPS production were 30 degrees C and 8.0, respectively. Sucrose (30 g/L) and corn steep powder (10 g/L) were the most suitable carbon and nitrogen source for both mycelial growth and EPS production. There was a distinguishable morphological changes in mycelium grown between organic and inorganic nitrogen sources. A smooth pellet growth with heavy hyphal thickness was observed in the medium containing organic nitrogen sources, whereas irregular pellets with less hairy region were formed in the medium containing inorganic nitrogen sources. More highly branched cells appearing in the medium of organic nitrogen sources seemed a favorable morphological form for both EPS production and mycelial growth. Under optimal culture conditions, the maximum concentrations of mycelial growth and EPS were 17.6 and 3.4 g/L in a 5-L stirred-tank fermenter. Four groups of EPSs (designated as Fr-I, Fr-II, Fr-III, and Fr-IV) were obtained from the culture filtrates by size exclusion chromatography (SEC), and their molecular characteristics were examined by a multiangle laser-light scattering (MALLS) and refractive index (RI) detector system. The weight-average molar masses of the Fr-I, Fr-II, Fr-III, and Fr-IV of EPS were determined to be 2.262 x 10(6), 3.348 x 10(5), 1.049 x 10(5), and 5.059 x 10(4) g/mol, respectively. All four EPSs showed very low polydispersity indices ranging from 1.00 to 1.18. The SEC/MALLS analysis revealed that the molecular shape of the Fr-I was a rigid sphere suspected to be an aggregate of complex polysaccharides, the Fr-II and Fr-III were nearly globular in shape, and the Fr-IV was an almost rodlike structure.