Purification and properties of extracellular polysaccharide (EPS) antigens produced by different mould species

Extracellular polysaccharide (EPS) antigens produced by different mould species were purified and partially characterized. Purification included (NH₄)₂SO₄ treatment, Sepharose CL-4B column chromatography and Con A-sepharose chromatography. The EPS of Penicillium digitatum, Mucor racemosus and Cladosporium cladosporioides showed high antigenic capacities. Immunologically the EPS were partially genus-specific, but cross-reactivity was observed. The EPS antigens produced by species of Penicillium, Aspergillus repens and Geotrichum candidum lost their immunological activity upon heating (100C) at pH 18, while the EPS antigen of M. racemosus, Rhizopus oligosporus and C. cladosporioides were stable under the same conditions. The dominant monosaccharides present in the EPS antigen were mannose, galactose and glucose. The EPS obtained from cultures of M. racemosus and R. oligosporus also contained rhamnose. In the EPS produced by Penicillium spp. and A. repens the galactose residues were determined to be immunodominant.     

Exopolysaccharide production by Streptococcus thermophilus SY: production and preliminary characterization of the polymer

AIMS: To evaluate the effect of yeast extract (YE) concentration, temperature and pH on growth and exopolysaccharide (EPS) production in a whey-based medium by Streptococcus thermophilus SY and to characterize the partially purified EPS. METHODS AND RESULTS: Factorial experiments and empirical model building were used to optimize fermentation conditions and the chemical composition, average molecular weight (MW) and rheological properties of aqueous dispersions of the EPS were determined. Exopolysaccharide production was growth associated and was higher (152 mg l(-1)) at pH 6.4 and 36 degrees C with 4 g l(-1) YE. High performance size exclusion chromatography of the partially purified EPS showed two peaks, with a weight average MW of 2 x 10(6) and 5 x 10(4), respectively. The EPS was a heteropolysaccharide, with a glucose : galactose : rhamnose ratio of 2 : 4.5 : 1. Its water dispersions had a pseudoplastic behaviour and showed a higher viscosity of xanthan solutions. SIGNIFICANCE AND IMPACT OF THE STUDY: The fermentation conditions and some properties of an EPS produced by Strep. thermophilus, a dairy starter organism, were described.     

Antigenic characterization of some potentially pathogenic mucoraceous fungi

The antigenic profiles of 10 mucoraceous fungi--Absidia corymbifera, Mortierella wolfii, Mucor miehei, M. pusillus, M. racemosus, Rhizopus arrhizus, R. microsporus, R. oryzae, R. rhizopodiformis, R. stolonifer,--Candida albicans and Aspergillus fumigatus were compared by crossed immunoelectrophoresis (XIE). Antigen-rich material was obtained from homogenized hyphae (or yeasts in the case of C. albicans), and antisera by multiple subcutaneous innoculation of rabbits with macerated but viable hyphal fragments of Ab. corymbifera, M. pusillus, R. oryzae or Asp. fumigatus. Unique and common antigens were demonstrable amongst the mucoraceous species although Mort. wolfii revealed little antigenic similarity with the others. Considerable sharing of antigens between Ab. corymbifera and M. pusillus was evident. Little or no cross reactivity was seen between extracts of C. albicans and Asp. fumigatus and the mucoraeceous antisera. R. oryzae and R. arrhizus, now regarded as synonymous, revealed close antigenic similarity. On the other hand, the distinction between both M. pusillus and M. miehei--which are regarded by some as belonging to a separate genus Rhizomucor--and less thermotolerant M. racemosus was reflected in their antigenic dissimilarity. Partial separation and characterization of antigens from the crude Absidia extract was achieved by concanavalin A-Sepharose chromatography. Antigens with and without affinity for concanavalin A could be demonstrated. Cross reactivity between Absidia antigens and M. pusillus antiserum appeared to be contained predominantly in material (possibly carbohydrate) which bound to concanavalin A and could be eluted with alpha-methyl-D-mannoside.     

Molecular and morphological identification of fungal species isolated from bealmijang meju

Bealmijang is a short-term aged paste made from meju, which is a brick of fermented soybeans and other ingredients. Different types of bealmijang are available depending on the geographic region or ingredients used. However, no study has clarified the microbial diversity of these types. We identified 17 and 14 fungal species from black soybean meju (BSM) and buckwheat meju (BWM), respectively, on the basis of morphology, culture characteristics, and internal transcribed spacer and beta-tubulin gene sequencing. In both meju, Aspergillus oryzae, Rhizopus oryzae, Penicillium polonicum, P. steckii, Cladosporium tenuissimum, C. cladosporioides, C. uredinicola, and yeast species Pichia burtonii were commonly found. Moreover, A. flavus, A. niger, P. crustosum, P. citrinum, Eurotium niveoglaucum, Absidia corymbifera, Setomelanomma holmii, Cladosporium spp. and unclassified species were identified from BSM. A. clavatus, Mucor circinelloides, M. racemosus, P. brevicompactum, Davidiella tassiana, and Cladosporium spp. were isolated from BWM. Fast growing Zygomycetous fungi is considered important for the early stage of meju fermentation, and A. oryae and A. niger might play a pivotal role in meju fermentation owing to their excellent enzyme productive activities. It is supposed that Penicillium sp. and Pichia burtonii could contribute to the flavor of the final food products. Identification of this fungal diversity will be useful for understanding the microbiota that participate in meju fermentation, and these fungal isolates can be utilized in the fermented foods and biotechnology industries.     

Detection of beta-galactofuranosidase production by Penicillium and Aspergillus species using 4-nitrophenyl beta-D-galactofuranoside

An assay was developed for detecting beta-galactofuranosidase produced by Penicillium and Aspergillus spp. The substrate for the assay, 4-nitrophenyl beta-D-galactofuranoside, was synthesized from penta-O-acetyl-beta-D-galactofuranose and 4-nitrophenol by a tin chloride catalyzed reaction followed by O-deacetylation. Aspergillus spp. produced only small quantities of beta-galactofuranosidase during 30 d at 25 degrees C. Only the biverticillate Penicillium spp. (P. funiculosum, P. islandicum, P. rubrum and P. tardum) produced substantial beta-galactofuranosidase after 1-4 weeks at 25 degrees C. No extracellular antigens of these four Penicillium spp. could be detected in culture filtrates by the sandwich ELISA technique when antibodies to the extracellular beta-galactofuranoside-containing polysaccharide antigen of P. digitatum was used. Antigens to all other Penicillium and Aspergillus spp. were easily detected in their culture filtrates.     

Detection of β-galactofuranosidase production by Penicillium and Aspergillus species using 4-nitrophenyl β-D-galactofuranoside

An assay was developed for detecting β-galactofuranosidase produced by Penicillium and Aspergillus spp. The substrate for the assay, 4-nitrophenyl β-D-galactofura-noside, was synthesized from penta-O-acetyl-β-D-galactofuranose and 4-nitrophenol by a tin chloride catalyzed reaction followed by O-deacetylation. Aspergillus spp. produced only small quantities of β-galactofuranosidase during 30 d at 25°C. Only the biverticillate Penicillium spp. ( P. funiculosum, P. islandicum, P. rubrum and P. tardum ) produced substantial β-galactofuranosidase after 1–4 weeks at 25°C. No extracellular antigens of these four Penicillium spp. could be detected in culture filtrates by the sandwich ELISA technique when antibodies to the extracellular β-galactofuranoside-containing polysaccharide antigen of P. digitatum was used. Antigens to all other Penicillium and Aspergillus spp. were easily detected in their culture filtrates.     

Identification of Volatile Metabolites from Five Fungal Species Cultivated on Two Media

Five fungal species, Aspergillus versicolor, Penicillium commune, Cladosporium cladosporioides, Paecilomyces variotii, and Phialophora fastigiata, were cultivated on two media, malt extract agar and dichloran glycerol agar. Culture flasks provided with inlet and outlet tubes were used and purified, and humidified air was constantly led through the flasks. Air samples from the cultures were sorbed on Tenax GR and analyzed by thermal desorption-gas chromatography. The produced volatile metabolites were analyzed by mass spectrometry. Various hydrocarbons, alcohols, ketones, ethers, esters, sulfur-containing compounds, and terpenes were identified. The most commonly produced substances were 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methylfuran, and dimethyl disulfide. The production was highly dependent on both medium and species.     

Optimization, purification, characterization and antioxidant activity of an extracellular polysaccharide produced by Paenibacillus polymyxa SQR-21

The optimization, purification and characterization of an extracellular polysaccharide (EPS) from a bacterium Paenibacillus polymyxa SQR-21 (SQR-21) were investigated. The results showed that SQR-21 produced one kind of EPS having molecular weight of 8.96 × 10⁵ Da. The EPS was comprised of mannose, galactose and glucose in a ratio of 1.23:1.14:1. The ratio of monosaccharides and glucuronic acid was 7.5:1. The preferable culture conditions for EPS production were pH 6.5, temperature 30 °C for 96 h with yeast extract and galactose as best N and C sources, respectively. The maximum EPS production (3.44 g L⁻¹) was achieved with galactose 48.5 g L⁻¹, Fe³⁺ 242 μM and Ca²⁺ 441 μM. In addition, the EPS showed good superoxide scavenging, flocculating and metal chelating activities while moderate inhibition of lipid peroxidation and reducing activities were determined. These results showed the great potential of EPS produced by SQR-21 to be used in industry in place of synthetic compounds.     

Production of a Novel Extracellular Polysaccharide by Lactobacillus sake 0-1 and Characterization of the Polysaccharide

A novel exopolysaccharide (EPS) produced by Lactobacillus sake 0-1 (CBS 532.92) has been isolated and characterized. When the strain was grown on glucose, the produced EPS contained glucose and rhamnose in a molar ratio of 3:2 and the average molecular mass distribution (M(infm)) was determined at 6 x 10(sup6) Da. At a concentration of 1%, the 0-1 EPS had better viscosifying properties than xanthan gum when measured over a range of shear rates from 0 to 300 s(sup-1), while shear-thinning properties were comparable. Rheological data and anion-exchange chromatography suggested the presence of a negatively charged group in the EPS. Physiological parameters for optimal production of EPS were determined in batch fermentation experiments. Maximum EPS production was 1.40 g (middot) liter(sup-1), which was obtained when L. sake 0-1 had been grown anaerobically at 20(deg)C and pH 5.8. When cultured at lower temperatures, the EPS production per gram of biomass increased from 600 mg at 20(deg)C to 700 mg at 10(deg)C but the growth rate in the exponential phase decreased from 0.16 to 0.03 g (middot) liter(sup-1) (middot) h(sup-1). EPS production started in the early growth phase and stopped when the culture reached the stationary phase. Growing the 0-1 strain on different energy sources such as glucose, galactose, mannose, fructose, lactose, and sucrose did not alter the composition of the EPS produced.     

嗜热链球菌MGB80-7所产胞外多糖的表型结构及其抗氧化活性

【背景】胞外多糖（exopolysaccharide,EPS）是乳酸菌生长代谢过程中所产生的一种次级代谢产物,除了可以改善产品质构和品质外,其生理功能也是近年来研究人员追捧的热点。【目的】探究乳酸菌EPS的表征特性和分子结构,揭示其与EPS益生特性之间的联系。【方法】以产EPS的嗜热链球菌（Streptococcus thermophilus,S. thermophilus） MGB80-7为研究对象,利用苯酚-硫酸法测定菌株EPS产量。采用离子交换柱层析和凝胶分子筛层析对该菌株所产EPS进行分离纯化,结合凝胶色谱、红外光谱及高效液相色谱对EPS表型结构进行剖析。此外,为确定EPS表型特征对其抗氧化活性的影响,测定了EPS对超氧阴离子、羟自由基及DPPH自由基等的清除能力。【结果】S. thermophilus MGB80-7在M17培养基中EPS产量较高,为（268.25±5.36） mg/mL,分离纯化后共得到2种多糖组分,其中中性多糖（WPS-807）分子量为1.028×10⁵ Da,主要由葡萄糖、半乳糖和甘露糖组成,并含有少量的鼠李糖和阿拉伯糖,酸性多糖（...     

Cell Walls and Lysis of Mortierella parvispora Hyphae

Walls of Mortierella parvispora, Pullularia pullulans, Absidia repens, Fusarium oxysporum, and of several Penicillium species varied in their susceptibilities to digestion by glucanase and chitinase. Polysaccharides were present in the residues remaining after enzymatic digestion. Acid hydrolysates of the walls contained glucose, glucosamine, and a small amount of galactose. The walls of M. parvispora, which also contained fucose, were the least digested by these two enzymes. Much of the M. parvispora wall material was resistant to decomposition by a heterogeneous soil community, and viable hyphae were not lysed by a glucanase-chitinase mixture. Walls of this fungus were fractionated, and the chemical composition of the fractions was determined. The chitin which was abundant in one of the fractions was apparently largely shielded from chitinase hydrolysis by a glucan. The ecological significance of these findings is discussed.     

A Note on the Identities of Organisms Causing Black Spot Spoilage of Meat

Four fungal species, Cladosporium cladosporioides, C. herbarum, Penicillium hirsutum and Aureobasidium pullulans were isolated from meat spoiled by black spot and shown to produce black spot colonies when inoculated on to sterile meat slices which were incubated at — 1°C. Penicillium hirsutum grew only on the meat surface but the other species penetrated into the tissues, apparently in response to arid conditions at the surface. It is clear from these observations that the traditional association of black spot spoilage with C. herbarum alone is incorrect.     

Potential of the volatile-producing fungus Muscodor albus for control of building molds

The possibility of using the volatile-producing fungus Muscodor albus for biofumigation against building molds was investigated. Several species of Aspergillus and Penicillium as well as fungi belonging to nine other genera were inhibited or killed in vitro by volatiles produced by potato dextrose agar or rye grain cultures of M. albus. Trichoderma viride was the only fungus that was not inhibited by M. albus volatiles. To test biofumigation as a preventative treatment against fungal colonization of building material, dry pieces of gypsum drywall were fumigated with grain cultures of M. albus in closed boxes. After a simulated water damage and incubation under saturated humidity for 2 weeks, untreated drywall developed natural fungal populations of about 10(5)-10(6) cfu/cm2, while drywall fumigated with M. albus culture (20 g/11 L) had nondetectable fungal populations. To test for curative ability, moist pieces of drywall heavily colonized with Cladosporium cladosporioides, Aspergillus niger, or Stachybotrys chartarum were fumigated for 48 h with grain cultures of M. albus. Cladosporium cladosporioides was eliminated within 48 h, while A. niger and S. chartarum were usually more resistant. However, a longer curative fumigation of 96 h was effective in reducing A. niger or naturally occurring mold populations by about 5 log values. The production of volatile organic compounds from 20 g of rye grain culture in 11 L containers was monitored by solid-phase micro extraction and gas chromatography. Concentrations of isobutyric acid, the most abundant volatile, increased gradually in the headspace until it reached 25 microg/L (m/v) within 96 h. The second and third most abundant compounds, 2-methyl-1-butanol and isobutanol, peaked at about 10 and 5 microg/L (m/v), respectively, within the first 24 h and declined gradually afterwards.     

Collagenolytic activity in several species of deuteromycetes under various storage conditions

The ability of deuteromycetes of the genera Penicillium, Aspergillus, and Botrytis to retain collagenolytic activity was studied after both 2 and 10 years of storage on a Czapek medium under a layer of mineral oil at 4 degrees C, as well as in silica gel granules at 20 and -60 degrees C. The enzymatic activity of several species, including Botrytis terrestris, Penicillium janthinellum, Penicillium chrysogenum, and Penicillium citrinum, was retained under both conditions of storage. Aspergillus repens retained enzymatic activity only if stored under a layer of mineral oil. The viability of conidia and the collagenolytic activity of Botrytis terrestris, P. janthinellum, P. chrysogenum, and Penicillium citrinum, maintained on silica gel for 10 years, depended on the storage temperature. The viability of the test strains improved after storage on a silica gel at -60 degrees C. A strain of Aspergillus repens lost its ability to dissolve collagen at various storage temperatures on the silica gel. The index of lysis for three strains of Penicillium deuteromycetes (Penicillium janthinellum, Penicillium chrysogenum, and Penicillium citrinum) increased after a 10-year storage on silica gel at -60 degrees C.     

ENVIRONMENTAL EFFECTS ON EXOPOLYMER PRODUCTION BY MARINE BENTHIC DIATOMS: DYNAMICS,CHANGES IN COMPOSITION,AND PATHWAYS OF PRODUCTION1

Marine benthic diatoms excrete large quantities of extracellular polymeric substances (EPS), both as a function of their motility system and as a response to environmental conditions. Diatom EPS consists predominantly of carbohydrate‐rich polymers and is important in the ecology of cells living on marine sediments. Production rates, production pathways, and monosaccharide composition of water‐soluble (colloidal) carbohydrates, EPS, and intracellular storage carbohydrate (glucans) were investigated in the epipelic (mud‐inhabiting) diatoms Cylindrotheca closterium (Ehrenburg), Navicula perminta (Grün.) in Van Heurck, and Amphora exigua Greg. under a range of experimental conditions simulating aspects of the natural environment. Cellular rates of colloidal carbohydrate, EPS, and glucan production were significantly higher during nutrient‐replete compared with nutrient‐limited growth for all three species. The proportion of EPS in the extracellular carbohydrate pool increased significantly (to 44%–69%) as cells became nutrient limited. Cylindrotheca closterium produced two types of EPS differing in sugar composition and production patterns. Nutrient‐replete cells produced a complex EPS containing rhamnose, fucose, xylose, mannose, galactose, glucose, and uronic acids. Nutrient‐limited cells produced an additional EPS containing mannose, galactose, glucose, and uronic acids. Both EPS types were produced under illuminated and darkened conditions. ¹⁴C‐labeling revealed immediate production of ¹⁴C‐glucan and significant increases in ¹⁴C‐EPS between 3 and 4 h after addition of label. The glucan synthesis inhibitor 2,6‐dichlorobenzonitrile significantly reduced ¹⁴C‐colloidal carbohydrate and ¹⁴C‐EPS. The glucanase inhibitor P‐nitrophenyl β‐d ‐glucopyranoside resulted in accumulation of glucan within cells and lowered rates of ¹⁴C‐colloidal and ¹⁴C‐EPS production. Cycloheximide prevented glucan catabolism, but glucan production and EPS synthesis were unaffected.     

总状毛霉对4-烯-3-酮甾体的生物转化研究

从土样中筛选到一株能转化甾体的菌株,经形态观察,鉴定为总状毛霉(Mucor racemosus)。首次利用该菌株对4-烯-3-酮类甾体衍生物进行生物转化,目的是合成具有潜在活性的羟基类4-烯-3-酮衍生物。转化条件为27℃,220r/min振荡培养4d。转化产物经乙酸乙酯萃取,用硅胶柱层析法分离,通过红外、质谱和核磁分析确定了甾体转化产物的化学结构。黄体酮生物转化得到的产物是14α-羟基-4-孕甾烯-3,20-二酮和7α,14α-二羟基-4-孕甾烯-3,20-二酮;4-雄烯二酮的转化产物是14α-羟基-雄甾-4-烯-3,17-二酮1、4α,17β-二羟基-雄甾-4-烯-3-酮和6α,17β-二羟基-雄甾-4-烯-3-酮。研究结果表明总状毛霉具有转化甾体的能力,对4-烯-3-酮类甾体进行生物转化的主要产物是14α-羟基甾体衍生物。     

Chemical composition of extracellular polysaccharides of cowpea rhizobia

The extracellular polysaccharides (EPS) of six strains of cowpea rhizobia were examined. The strains (MI50A, M6-7B, IRC253) produced polysaccharides containing glucose, galactose and mannose in a molar ratio of 2:1.1:1, 1:1.3:3.1 and 1:1.3:3.5 respectively. Two strains (513-B and Ez-Aesch) produced polysaccharides containing galactose and mannose in a molar ratio of 2:3. Mannose was the only sugar detected in the EPS of strain IRC291. Pyruvate, acetate, glucuronic acid and galacturonic acid were not detected in any strain.Abbreviations EPS Extracellular polysaccharide - YEMA yeast-extract mannitol agar - YEMB yeast extract mannitol broth     

Host-range related structural features of the acidic extracellular polysaccharides of Rhizobium trifolii and Rhizobium leguminosarum

Proton nuclear magnetic resonance (1H NMR) and fast atom bombardment mass spectrometric analyses were performed on enzymatically derived oligosaccharides from the acidic excreted polysaccharides (EPS) from representative bacterial strains of the pea-nodulating symbiont, Rhizobium leguminosarum (128C53, 128C63, and 300) and the clover-nodulating symbiont, Rhizobium trifolii (NA-30, ANU843, 0403, TA-1, LPR5035, USDA20.102, and 4S). The results revealed structural similarities and differences between EPS of these two species. Octasaccharide units containing galactose, glucuronic acid, alpha-L-threo-hex-4-enopyranosyluronic acid, and glucose in a molar ratio of 1:1:1:5 were obtained from the EPS of the three R. leguminosarum strains and had the same primary glycosyl sequence and location of pyruvate, acetate, and 3-hydroxybutyrate substituents. About 80% of the galactose residues were acylated with 3-hydroxybutyrate, and there were two acetyl groups per repeating unit distributed between the 2 glucose residues of the main chain-derived sequence of the octasaccharides. In contrast, the R. trifolii strains had varied EPS structures, each of which differed from the common R. leguminosarum EPS structure. The EPS from one group of R. trifolii strains (0403 and LPR5035) most closely resembled the R. leguminosarum EPS but differed in that a lower number of galactose and glucose residues were substituted by 3-hydroxybutyryl and acetyl groups, respectively. The EPS from a second group of R. trifolii strains (ANU843, TA-1, and NA-30) was even more different than the R. leguminosarum EPS. These R. trifolii octasaccharides bore a single acetyl group on O-3 of the glucuronic acid residue. In addition, the level of acylation by 3-hydroxybutyryl groups was 50% of that present in the R. leguminosarum EPS. The remaining two strains of R. trifolii (USDA20.102 and 4S) had very different patterns of acylation to each other and to all of the other strains. The EPS from strain USDA20.102 practically lacked 3-hydroxybutyryl groups and had a unique degree and pattern of acetylation. The oligomers from the EPS of R. trifolii strain 4S completely lacked 3-hydroxybutyryl groups and galactose. The latter EPS contained only one O-1-carboxyethylidene group and had a different degree and pattern of acetylation. Interestingly, these two latter strains differ from the other R. trifolii strains in nodulation rates on rare clover species in the Trifolium cross-inoculation group. Thus, we define several groups of R. trifolii based upon their EPS structures and establish their similarities and distinct differences with the EPS of R. leguminosarum.(ABSTRACT TRUNCATED AT 400 WORDS)     

UDP-N-acetylglucosamine 4-epimerase activity indicates the presence of N-acetylgalactosamine in exopolysaccharides of Streptococcus thermophilus strains

The monomer composition of the exopolysaccharides (EPS) produced by Streptococcus thermophilus LY03 and S. thermophilus Sfi20 were evaluated by high-pressure liquid chromatography with amperometric detection and nuclear magnetic resonance spectroscopy. Both strains produced the same EPS composed of galactose, glucose, and N-acetylgalactosamine. Further, it was demonstrated that the activity of the precursor-producing enzyme UDP-N-acetylglucosamine 4-epimerase, converting UDP-N-acetylglucosamine into UDP-N-acetylgalactosamine, is responsible for the presence of N-acetylgalactosamine in the EPS repeating units of both strains. The activity of UDP-N-acetylglucosamine 4-epimerase was higher in both S. thermophilus strains than in a non-EPS-producing control strain. However, the level of this activity was not correlated with EPS yields, a result independent of the carbohydrate source applied in the fermentation process. On the other hand, both the amounts of EPS and the carbohydrate consumption rates were influenced by the type of carbohydrate source used during S. thermophilus Sfi20 fermentations. A correlation between activities of the enzymes alpha-phosphoglucomutase, UDP-glucose pyrophosphorylase, and UDP-galactose 4-epimerase and EPS yields was seen. These experiments confirm earlier observed results for S. thermophilus LY03, although S. thermophilus Sfi20 preferentially consumed glucose for EPS production instead of lactose in contrast to the former strain.     

Isolation and Characterization of the Serotype g Carbohydrate Moiety from an Enzyme Lysate of Streptococcus mutans 6715 Cell Walls

The serotype-specific carbohydrate moiety of Streptococcus mutans was isolated by mild degradation of purified cell walls with a cell-wall lytic enzyme. Cell walls of serotype g S. mutans strain 6715 were digested with M1 enzyme, an endo-N-acetylmuramidase purified from culture supernatants of Streptomyces globisporus strain 1829. The enzyme lysate of the cell walls was applied to a CM Sephadex C-25 column to remove the M1 enzyme from the cell wall lysate and then subjected to Sephadex G-100 column chromatography. Carbohydrate antigens with serotype g specificity, designated M1g, and a peptidoglycan—polysaccharide complex lacking serotype specificity (M1PG) were separated. Purified serotype g antigen was also obtained by autoclaving the S. mutans 6715 whole cells in saline at 120 C for 30 min. The extract was applied to a DEAE Sephadex A-25 column to remove nucleic acids and teichoic acids. The unbound peak fraction was concentrated and re-chromatographed on a Bio-Gel P-100 column. The void volume fraction contained serotype g carbohydrate and was designated RRg antigen. M1g and RRg antigens formed a band of identity with anti-serotype g serum by immunodiffusion. These antigens were composed mainly of galactose, glucose, and rhamnose at an approximate weight ratio of 8 : 4 : 1, while constituent sugars of M1PG consisted of rhamnose and glucose, with no detectable galactose. M1g also contained peptidoglycan residues other than threonine, an interpeptide bridge component of the native cell wall peptidoglycan. Marked inhibition of the quantitative precipitin reaction between M1g and anti-serotype g serum was obtained with melibiose and galactose, which suggests that the immunodeterminant of the serotype g carbohydrate is an α-linked galactose-glucose terminal linkage.