Purification and characterization of a component produced by Lactobacillus fermentum that inhibits the adhesion of K88 expressing Escherichia coli to porcine ileal mucus

It has previously been shown that Lactobacillus fermentum strain 104r releases compounds into its culture fluid that inhibit the adhesion of enterotoxigenic Escherichia coli K88. The aim of the present study was to purify and identify this compound. Judged by gel filtration, the compound was found to be approximately 1700 kDa. The amount of active compound increased upon prolonged incubation, while the number of viable cells reduced, suggesting that the activity was coming from dead cells. As the activity can be destroyed by lysozyme treatment and contains glucose, N -acetylglucosamine and galactose, it was concluded that cell wall fragments are the active agent, although cell wall preparations did not have the same effect. Adhesion to some mucus fractions could be inhibited by spent culture fluid, indicating specific interaction between mucus and the active compound. The compound was not able to interfere with the adhesion of E. coli 1107 to neutral lipids from mucus which contain a glycolipid receptor for K88 fimbriae.     

Purification and characterization of a surface-binding protein from Lactobacillus fermentum RC-14 that inhibits adhesion of Enterococcus faecalis 1131

Lactobacilli have been shown to be important in the maintenance of the healthy urogenital flora. One strain, Lactobacillus fermentum RC-14, releases surface-active components which can inhibit adhesion of uropathogenic bacteria. Using a quantitative method for determining inhibition of adhesion, a protein with high anti-adhesive properties against Enterococcus faecalis 1131 was purified. The N-terminal sequence of the 29-kDa protein was identical to that of a collagen-binding protein from Lactobacillus reuteri NCIB 11951, and exhibited close homology with a basic surface protein from L. fermentum BR11. The results suggest that this anti-adhesive cell surface protein of Lactobacillus could protect against uropathogens by preventing their adhesion. the Federation of European Microbiological Societies.     

Purification and characterization of acid urease from Lactobacillus fermentum

Summary Acid urease was purified to an electrophoretically homogeneous state, and the molecular weight was estimated to be 220 000. The enzyme consisted of three kinds of subunits, designated , and , with molecular weights of 67 000, 16 800 and 8600, respectively, in a (₁ \₂₁)₂ structure. The isoelectric point of the enzyme was 4.8. The nickel content was found to be 1.9 atoms of nickel per ₁₂₁ unit. The amino acid profile was different from those of known bacterial neutral ureases. The enzyme was most active at pH 2 and around 65° C. It was stable between pH 3 and 9, and below 50° C. The K _m for urea was 2.7 mM at pH 2. The enzyme activity was inhibited by Ag⁺, Hg²⁺, Cu²⁺, p-chloromercuribenzoate and acetohydroxamate. The enzyme was separated into three subunits by reverse phase HPLC. The amino terminal amino acid sequences of the subunits , and were Ser-Phe-Asp-Met-, Met-Val-Pro-Gly- and Met-Arg-Leu-Thr-, respectively.Offprint requests to: S. Kakimoto     

Adhesion to porcine squamous epithelium of saccharide and protein moieties of Lactobacillus fermentum strain 104-S.

The mechanism by which Lactobacillus fermentum strain 104-S adheres to porcine squamous epithelium was investigated by studying the adsorption to epithelial cells, and control surfaces, of radioactively labelled material released from the bacterial cells by water extraction. The released material was fractionated by gel filtration and the adsorption of pronase-sensitive and -resistant material in the various fractions to porcine gastric tissue and the control surfaces of polystyrene and immobilized bovine serum albumin (BSA) was determined. The fraction with affinity for the epithelium was characterized by enzymic degradation, periodate oxidation, lipid extraction, and protein and carbohydrate analyses. The adsorption pattern of radioactively labelled crude released material mimicked the adhesion of whole labelled cells to polystyrene and to gastric squamous tissue pieces. On fractionation, the pattern of adsorption to polystyrene and BSA was different from that obtained for the tissue pieces. Considerably less labelled pronase-stable material bound to surfaces of polystyrene and BSA, as compared with the tissue, suggesting that the pronase-resistant component has a tissue-specific affinity. After pronase treatment of the fraction of M(r) about 20,000 (20 K) containing labelled components with affinity for the epithelium, only saccharides were detected. Radioactivity was lost after hydrolysis with HCl, and therefore this pronase-resistant labelled component must be a saccharide. It is concluded that protein moieties in the extract have an affinity for several surfaces, including polystyrene, and that saccharide moieties have a specific affinity for the gastric squamous epithelium.     

Purification and Characterization of a Surface Protein from Lactobacillus fermentum 104R That Binds to Porcine Small Intestinal Mucus and Gastric Mucin

An adhesion-promoting protein involved in the binding of Lactobacillus fermentum strain 104R to small intestinal mucus from piglets and to partially purified gastric mucin was isolated and characterized. Spent culture supernatant fluid and bacterial cell wall extracts were fractionated by ammonium sulfate precipitation and gel filtration. The active fraction was purified by affinity chromatography. The adhesion-promoting protein was detected in the fractions by adhesion inhibition and dot blot assays and visualized by polyacrylamide gel electrophoresis (PAGE), sodium dodecyl sulfate-PAGE, and Western blotting with horseradish peroxidase-labeled mucus and mucin. The active fraction was characterized by estimating the relative molecular weight and by assessing the presence of carbohydrates in, and heat sensitivity of, the active region of the adhesion-promoting protein. The purified protein was digested with porcine trypsin, and the peptides were purified in a SMART system. The peptides were tested for adhesion to horseradish peroxidase-labeled mucin by using the dot blot adhesion assay. Peptides which bound mucin were sequenced. It was shown that the purified adhesion-promoting protein on the cell surface of L. fermentum 104R is extractable with 1 M LiCl and low concentrations of lysozyme but not with 0.2 M glycine. The protein could be released to the culture supernatant fluid after 24 h of growth and had affinity for both small intestinal mucus and gastric mucin. In the native state this protein was variable in size, and it had a molecular mass of 29 kDa when denatured. The denatured protein did not contain carbohydrate moieties and was not heat sensitive. Alignment of amino acids of the adhering peptides with sequences deposited in the EMBL data library showed poor homology with previously published sequences. The protein represents an important molecule for development of probiotics.     

Purification and characterization of alpha-L-fucosidase from Bacillus circulans grown on porcine gastric mucin.

Bacillus circulans isolated from soil was found to produce two types of alpha-L-fucosidase differing in substrate specificity. One was able to liberate L-fucose from porcine gastric mucin (PGM), but not from artificial substrates, including p-nitrophenyl and methyl alpha-L-fucosides, while the other acted not on PGM but on p-nitrophenyl alpha-L-fucoside. The production of the former enzyme was enhanced about 150 times as much by PGM added to the medium as by glucose. The alpha-L-fucosidase acting on PGM was purified from the culture fluid obtained with PGM medium by ammonium sulfate fractionation and subsequent column chromatography. The purified enzyme was found to be homogeneous by PAGE and its molecular weight was estimated to be approximately 285,000. The optimum pH was found to be 5.5 to 6.5 and the stable pH range was 4.5 to 9.0. The enzyme decomposed various blood group O(H) active substances such as PGM, human milk and human saliva, and moreover acted on A-, B-, and O-erythrocytes. The enzyme was shown to cleave alpha-(1----2)-, (1----3)-, and (1----4)-L-fucosidic linkages in various glycoproteins and oligosaccharides, but failed to hydrolyze alpha-(1----6)-L-fucosic linkages in 6-O-alpha-L-fucopyranosyl-N-acetylglucosamine and intact bovine thyroglobulin.     

Purification and characterization of fish surface mucin

Fish surface mucin from Pampus argenteus was extracted with different organic solvents and the residue passed through Sephadex G-200. The major peak was purified by DEAE-Cellulose chromatography and five fractions were obtained. Carbohydrate and protein contents showed that major peak is a glycoprotein. Rechromatography of this component on the Sephadex G-200 column gave a single peak, with an estimated minimal molecular weight of 6.9 X 10(5). Analysis of individual sugar components revealed the presence of galactose, glucose, mannose, arabinose, N-acetyl glucosamine, N-acetyl galactosamine and sialic acid. The most represented amino acids are threonine, serine, proline, glutamic acid and glycine. The N-terminal amino acid end was blocked. Nearly 47% of sulphate was acid labile. Sialic acid and fucose were released rapidly by mild acid hydrolysis. The presence of blood group-A activity suggests that some kind of terminal alpha-Gal-NAC may be present.     

发酵乳杆菌多铜氧化酶的异源表达及酶学性质

生物胺是一种存在于发酵食品中的含氮小分子有机化合物,过量摄入可能引起过敏或其他不良反应。利用酶法降解是减少发酵食品中生物胺含量从而保障食品安全的有效方法之一。文中成功克隆了来源于发酵乳杆菌的多铜氧化酶基因,在大肠杆菌中表达的酶活水平为484 U/L。通过镍柱亲和层析方法获得了此多铜氧化酶的纯酶。该多铜氧化酶的最适反应温度为50℃,最适反应pH为3.5,其K_m为1.3 mmol/L,V_(max)为7.67×10~(-2) mmol/(L·min)。对酶的应用特性研究表明,来源于发酵乳杆菌的多铜氧化酶对18%(W/F)NaCl有一定的耐受性,并可降解包括色胺、苯乙胺、腐胺、尸胺、组胺、酪胺和亚精胺在内的7种生物胺。其中它对组胺和酪胺的降解能力最高,分别为51.6%和40.9%。此外,该酶对酱油中的生物胺也有普遍降解作用,使用较低酶量(500 U/L)时,对酱油中总胺的降解率达到10.6%。多铜氧化酶具备降解发酵食品中生物胺的潜力,为进一步实现这类食品酶的实际应用奠定基础。     

Purification and characterization of cystathionine γ-lyase from Lactobacillus fermentum DT41

A homo-tetrameric ca. 140-kDa cystathionine γ-lyase was purified to homogeneity from Lactobacillus fermentum DT41 by four chromatographic steps. This was the first enzyme responsible for amino acid catabolism purified from lactobacilli. The activity is pyridoxal-5'-phosphate dependent and the enzyme catalyzes the α,γ-elimination reaction of l -cystathionine producing l -cysteine, ammonia and α-ketobutyrate. The cystathionine γ-lyase produced a free thiol group, a keto acid component and ammonia from several amino acids, including l -cysteine and methionine, and amino acid derivatives. l -Cystine was the best substrate. The enzyme was stable in the conditions of cheese ripening and may contribute to the biosynthesis of sulfur-containing compounds.     

Rat small intestinal mucin: isolation and characterization of a water-soluble mucin fraction

A water-soluble fraction of sialoglycoprotein containing sulfate was isolated from the mucosal scrapings of the rat small intestine without prior treatment with proteolytic enzymes. Chromatography of the water-soluble mucin on a DEAE-cellulose column gave three main fractions: a major carbohydrate-rich fraction containing sulfate (IGP-A), one high in protein content, and a third with a composition similar to the starting material. Fraction IGP-A was resolved into two components by ultracentrifugation and disc-gel electrophoresis. The higher molecular-weight species of IGP-A was separated from the second component by Sepharose-4B chromatography. These two glycoprotein fractions designated IGP-A₁ and IGP-A₂ had the same chemical composition as IGP-A.     

Identification and characterization of a basic cell surface-located protein from Lactobacillus fermentum BR11.

Extraction of Lactobacillus fermentum BR11 cells with 5 M LiCl yielded a preparation containing a single predominant polypeptide with an apparent molecular mass of 32 kDa. A clone encoding an immunoreactive 32-kDa polypeptide was isolated from a pUC18 library of L. fermentum BR11 DNA by screening with an antiserum raised against whole cells of L. fermentum BR11. Sequence determination of the insert in the clone revealed a complete 795-bp open reading frame (ORF) that defines a 28,625-Da polypeptide (BspA). N-terminal sequencing of the LiCl-extracted polypeptide from L. fermentum BR11 confirmed that it is the same as the cloned BspA. BspA was found to have a sequence similar to those of family III of the bacterial solute-binding proteins. The sequences of two ORFs upstream of bspA are consistent with bspA being located in an operon encoding an ATP-binding cassette-type uptake system. Unusually, BspA contains no lipoprotein cleavage and attachment motif (LXXC), despite its origin in a gram-positive bacterium. Biotin labelling and trypsin digestion of whole cells indicated that this polypeptide is exposed on the cell surface. The isoelectric point as predicted from the putative mature sequence is 10.59. It was consequently hypothesized that the positively charged BspA is anchored by electrostatic interaction with acidic groups on the cell surface. It was shown that BspA could be selectively removed from the surface by extraction with an acidic buffer, thus supporting this hypothesis.     

Purification and characterization of a feruloyl esterase from the intestinal bacterium Lactobacillus acidophilus

Dietary ferulic acid (FA), a significant antioxidant substance, is currently the subject of extensive research. FA in cereals exists mainly as feruloylated sugar ester. To release FA from food matrices, it is necessary to cleave ester cross-linking by feruloyl esterase (FAE) (hydroxycinnamoyl esterase; EC 3.1.1.73). In the present study, the FAE from a human typical intestinal bacterium, Lactobacillus acidophilus, was isolated, purified, and characterized for the first time. The enzyme was purified in successive steps including hydrophobic interaction chromatography and anion-exchange chromatography. The purified FAE appeared as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular mass of 36 kDa. It has optimum pH and temperature characteristics (5.6 and 37 degrees C, respectively). The metal ions Cu(2+) and Fe(3+) (at a concentration of 5 mmol liter(-1)) inhibited FAE activity by 97.25 and 94.80%, respectively. Under optimum pH and temperature with 5-O-feruloyl-L-arabinofuranose (FAA) as a substrate, the enzyme exhibited a K(m) of 0.0953 mmol liter(-1) and a V(max) of 86.27 mmol liter(-1) min(-1) mg(-1) of protein. Furthermore, the N-terminal amino acid sequence of the purified FAE was found to be A R V E K P R K V I L V G D G A V G S T. The FAE released FA from O-(5-O-feruloyl-alpha-L-arabinofuranosyl)-(1-->3)-O-beta-D-xylopyranosyl-(1-->4)-D-xylopyranose (FAXX) and FAA obtained from refined corn bran. Moreover, it released two times more FA from FAXX in the presence of added xylanase.     

Isolation and characterization of a Lactobacillus fermentum temperate bacteriophage from Chinese yogurt

AIMS: The aim of this study was to investigate the properties of temperate bacteriophage of Lactobacillus fermentum, based on its morphology, restriction patterns, protein profile and the impact on the growth of host strain. METHODS AND RESULTS: With Mitomycin C, seven temperate phages were induced from Lactobacilli derived from Chinese yogurt. The temperate phages induced belong to the most common Bradley's group B, having hexagonal head and long, noncontractile tail. They were furthermore confirmed to be the same bacteriophage by identical restriction patterns. SDS-PAGE profile showed that the phage studied had one major structure protein about 31.9 kDa. The presence of the prophage influenced the cell shape and colony size of its lysogenic strain. CONCLUSIONS: The phage obtained had similar, but not complete identical properties with other L. fermentum phages reported. It influenced the growth behaviour of its lysogenic strain. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides some information about bacteriophages occurring in the Chinese yoghurt manufacture and contributes to our knowledge on the bacteriophage diversity in the dairy industry.     

Purification and characterization of a protein from HeLa cells that binds with high affinity to the estrogen response element, GGTCAGCGTGACC

A non-histone protein, NHP1, that binds with high affinity to the estrogen response element (ERE), GGTCAGCGTGACC, has been purified approximately 45,000-fold from HeLa cells by a combination of chromatography on Sephacryl S-300, heparin-Sepharose, Mono Q (FPLC), and sequence-specific oligonucleotide-Sepharose. The native protein has a molecular weight of 170,000 and is composed of two polypeptides of 85 and 75 kDa. The two polypeptides are different as judged by peptide mapping, and only the 85-kDa polypeptide can be cross-linked to the bromodeoxyuridine-substituted synthetic ERE by UV irradiation. The native protein binds to the ERE with an apparent KD of 1 x 10(-11) M and has a pI of 5. The contact points of the protein with individual bases of the ERE have been determined by using partially depurinated and depyrimidinated synthetic oligonucleotides. The strongest contact points of NHP1 with the ERE are 5'AGCG3' in the center of the palindrome and differ from those of the estrogen receptor. NHP1 appears to produce specific nicks around the central CpGs of the ERE, thereby suggesting that it may play a role in active demethylation of mCpGs.     

Purification and characterization of OBF1: a Saccharomyces cerevisiae protein that binds to autonomously replicating sequences.

We previously identified a protein activity from Saccharomyces cerevisiae, OBF1, that bound specifically to a DNA element present in autonomously replicating sequences ARS120 and ARS121 (S. Eisenberg C. Civalier, and B. K. Tye, Proc. Natl. Acad. Sci. USA 85:743-746, 1988). OBF1 has now been purified to near homogeneity by conventional protein and DNA affinity chromatography. Electrophoresis of the purified protein in sodium dodecyl sulfate-polyacrylamide gels revealed the presence of two polypeptides. The major protein band had a relative molecular size of 123 kilodaltons, and the minor protein band, which constituted only a small fraction of total protein, had a molecular size of 127 kilodaltons. Both polypeptides cochromatographed with the specific ARS120 DNA-binding activity and formed a stable protein-DNA complex, isolatable by sedimentation through sucrose gradients. Using antibodies, we have shown that both polypeptides are associated with the isolated protein-DNA complexes. The ARS DNA-binding activity had a Stokes radius of 54 A (5.4 nm) and a sedimentation coefficient of 4.28S, as determined by gel filtration and sedimentation through glycerol gradients, respectively. These physical parameters, together with the denatured molecular size values, suggested that the proteins exist in solution as asymmetric monomers. Since both polypeptides recognized identical sequences and had similar physical properties, they are probably related. In addition to binding to ARS120, we found that purified OBF1 bounds with equal affinity to ARS121 and with 5- and 10-fold-lower affinity to ARS1 and HMRE, respectively. Furthermore, in the accompanying paper (S. S. Walker, S. C. Francesconi, B. K. Tye, and S. Eisenberg, Mol. Cell. Biol. 9:2914-2921, 1989), we demonstrate the existence of a high, direct correlation between the ability of purify OBF1 to bind to ARS121 and optimal in vivo ARS121 activity as an origin of replication. These findings, taken together, suggest a role for OBF1 in ARS function, presumably at the level of initiation of DNA replication at the ARS.     

Comparative characterization of spirosomes isolated from Lactobacillus brevis, Lactobacillus fermentum, and Lactobacillus buchneri

Spirosomes, cytoplasmic fine spirals, were isolated and purified from Lactobacillus brevis ATCC 8287, L. fermentum F-1, and L. buchneri ATCC 4005, and their morphological, biochemical, and immunological properties were investigated. The spirosomes of these lactobacilli were morphologically indistinguishable from one another, and they had the same buoyant density of 1.320 g/cm3 in CsCl. All of the spirosomes were composed of a single protein, spirosin, with an apparent molecular weight of about 95,000 for L. brevis and L. fermentum and of about 96,000 for L. buchneri as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The spirosins from the three lactobacilli were compared by peptide mapping on SDS-PAGE after cleavage with N-chlorosuccinimide and limited proteolysis with Staphylococcus aureus V8 protease. The peptide map of the L. brevis spirosin was identical with that of the L. fermentum spirosin, whereas it was markedly different from the L. buchneri spirosin. The amino acid composition of the L. brevis spirosin was almost similar to that of the L. fermentum spirosin, while it differed appreciably from the L. buchneri spirosin. Using antiserum against the L. brevis spirosin, immunodiffusion test revealed that the antigenicity of the spirosomes from L. brevis was identical with that from L. fermentum, whereas it was partially different from that from L. buchneri.     

Purification and characterization of endo-beta-galactosidase from Escherichia freundii induced by hog gastric mucin

A new procedure for inducing and purifying endo-beta-galactosidase from Escherichia freundii was described. The enzyme was found to be induced with high efficiency in culture medium containing Smith-degraded hog gastric mucin, which was prepared from a commercially available starting material. Endo-beta-galactosidase was then purified by ammonium sulfate fractionation, DEAE-Sephadex chromatography, and affinity chromatography on Sepharose conjugated with the Smith-degraded mucin. The enzyme thus purified by only three steps showed no other glycosidase or protease activities and had higher specific activity compared to the previous method. This new method has a great advantage since the gastric mucin is abundantly available and the efficiency of enzyme production was high without significant induction of exoglycosidase. The hydrolysis of oligosaccharides, glycosphingolipid, and keratansulfate was studied by using this newly purified enzyme. Kinetic data indicate that hydrolyzability of these substrates is largely affected by substrate concentration, enzyme concentration and the structure of substrates. Based on these results, the specificity of E. freundii endo-beta-galactosidase was discussed.     

Purification and characterization of an alpha-actinin-like protein from porcine kidney

An alpha-actinin-like protein was partially purified from the Triton-insoluble cytoskeleton of porcine kidney by 0.6 M MgCl2 treatment, ammonium sulfate fractionation, DEAE-cellulose chromatography and hydroxyapatite chromatography. Apparent purity of the kidney protein was approximately 90% by quantitative densitometry of Coomassie-stained polyacrylamide gels. The kidney alpha-actinin-like protein is very similar to muscle alpha-actinins by the following criteria: (1) both kidney protein and muscle alpha-actinins bind to F-actin at a similar ratio; (2) both proteins demonstrate no difference in the actomyosin turbidity assay and the ATPase assay for alpha-actinin activity; (3) both native proteins contain a large core of identical molecular weight resistant to trypsin; (4) on two-dimensional gels, both kidney protein and muscle alpha-actinins have similar isoelectric points of 5.9-6.1. However, kidney alpha-actinin-like protein is not identical in every respect with muscle alpha-actinins. Electrophoretic mobility of the kidney protein is slightly greater than that of chicken gizzard alpha-actinin and is identical to that of a component of chicken skeletal muscle alpha-actinin. One-dimensional peptide mappings of the kidney protein and muscle alpha-actinins were significantly different from each other. The interaction between kidney alpha-actinin-like protein and F-actin is sensitive to Ca2+. Similar Ca2+-sensitivity was observed with other non-muscle cell alpha-actinins.     

Factors involved in binding of Lactobacillus plantarum Lp6 to rat small intestinal mucus

AIM: To investigate the adhesion determinants of Lactobacillus plantarum Lp6, a dairy isolate. METHODS AND RESULTS: Small intestinal mucus extracted from rats was used as a substrate for adhesion. Adhesion determinants were studied by physical, chemical and enzymatic pretreatments of the bacteria, and adhesion inhibition assay. The mannose-specific adhesins were explored by studying the effect of d-mannose on adhesion and the yeast-agglutinating ability of the bacteria. It was found that adhesion decreased after bacteria were treated with sodium metaperiodate, protease K, trypsin, lithium chloride and trichloroacetic acid. However, adhesion did not decrease after trypsin-treated bacteria were incubated with cell surface protein extract. Cell surface bound exopolysaccharides were found to inhibit the adhesion. D-mannose inhibited the adhesion in a dose-dependent manner. The bacteria could significantly agglutinate yeast and lost this ability after protease K treatment. CONCLUSIONS: Adhesion was mainly mediated by the mannose specific adhesins, which might be proteins that reversibly bind to the cell surface components. Cell surface-bound exopolysaccharides were also involved in adhesion. SIGNIFICANCE AND IMPACT OF THE STUDY: The mannose-specific adhesion of Lact. plantarum Lp6 to rat mucus might be important for competing with pathogens-binding sites in gut, which may be used to resist the colonization of the pathogens.