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1.
固氨粪产碱菌野生型Ａ１５０１菌株及其胞外多糖（ＥＰＳ）突变株Ｅｘｏ＋＋（Ａ１５３２）和ＥｘＯ－（Ａ１５３１）,以及ｎｉｆＡ和ｎｔｒＣ－ｎｉｆＡ转化子（Ａ１５１３和Ａ１５２３）的ＥＰＳ,由高分子量（２５０ｋＤ左右）组分（ＥＰＳＨ）和低分子量小于４０ｋＤ组分（ＥＰＳＬ）组成。两个组分中均含有葡萄糖、半乳糖、果糖和戊糖,其主要成分葡萄糖和半乳糖的分子摩尔比：Ａ１５０１－ＥＰＳＨ为２：１、ＥＰＳＬ为３：１;Ａ１５３１－ＥＰＳＨ为２：１、ＥＰＳＬ为１：１;Ａ１５３２－ＥＰＳＨ为８：１、ＥＰＳＬ为５：１;Ａ１５１３－ＥＰＳＨ和ＥＰＳＬ均为４：１;Ａ１５２３－ＥＰＳＨ为４：１、ＥＰＳＬ为８：１。高分子量ＥＰＳ中还含有多肤,其氨基酸组分在各突变株和转化子之间差异明显,而ＥＰＳＬ中仅含有痕量多肽。  相似文献   

2.
Eight apple pomace liquefaction juices were produced to characterize soluble cell wall material released by the action of pectolytic and cellulolytic enzyme preparations. Very high colloid values from 9.7 to 19.6 g/L were recovered from the juices by ethanol precipitation. The crude polysaccharides consisted mainly of galacturonic acid (49-64 mol %), arabinose (14-23 mol %), galactose (6-15 mol %), and minor amounts of rhamnose, xylose, and glucose. Separation of the polysaccharides by anion-exchange chromatography yielded one neutral, one slightly acidic, and one acidic polymer accounting for 60% of total colloids. Preparative size exclusion chromatography of the acidic fractions resulted in four polymers of different molecular weights and different sugar compositions. Among them, high molecular weight arabinans and rhamnogalacturonans as well as oligomeric fractions consisting of only galacturonic acid could be found. Linkage studies were performed on neutral fractions from anion-exchange chromatography and size exclusion chromatography. They revealed highly branched arabinans, xyloglucans, and mainly type I arabinogalactans.  相似文献   

3.
Wild blueberries are a rich source of polyphenols and other compounds that are highly metabolized by the intestinal microbiota and may, at the same time, affect the intestinal environment itself. A repeated-measure, crossover dietary intervention on human volunteers was designed to study the effect of six week consumption of a wild blueberry ( Vaccinium angustifolium ) drink, versus a placebo drink, in modulating the intestinal microbiota. Relative to total eubacteria, Bifidobacterium spp. significantly increased following blueberry treatment (P ≤ 0.05), while Lactobacillus acidophilus increased after both treatments (P ≤ 0.05). No significant differences were observed for Bacteroides spp., Prevotella spp., Enterococcus spp., and Clostridium coccoides . Bifidobacteria, which have been largely proposed to be of benefit for the host, appeared to be selectively favored suggesting an important role for the polyphenols and fiber present in wild blueberries. Results obtained suggest that regular consumption of a wild blueberry drink can positively modulate the composition of the intestinal microbiota.  相似文献   

4.
The production of galactooligosaccharides (GOSs) by transgalactosylation using beta-galactosidase from Bifidobacterium longum BCRC 15708 was studied. Other than lactose, galactose, and glucose, two types of GOSs, tri- and tetrasaccharides, were formed after beta-galactosidase action on 40% lactose. Trisaccharides were the major type of GOS formed. Generally, an increase of the initial lactose concentration in the reaction mixture resulted in a higher GOS production. A maximum yield of 32.5% (w/w) GOSs could be achieved from 40% lactose solution at 45 degrees C, pH 6.8, when the lactose conversion was 59.4%. The corresponding productivity of GOSs was 13.0 g/(L.h). Transgalactosylation activity of beta-galactosidase from a test organism showed a relatively lower sensitivity toward glucose and galactose than that from other organisms. The addition of 5% or 10% glucose or galactose to the reaction mixture did not significantly (p>0.05) reduce the transgalactosylation reaction of beta-galactosidase.  相似文献   

5.
The inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifidobacterium longum was investigated using two lipid model systems. All eight strains, including six strains of L. acidophilus and two strains of B. longum, demonstrated an inhibitory effect on linoleic acid peroxidation. The inhibitory rates on linoleic acid peroxidation ranged from 33 to 46% when 1 mL of intracellular cell-free extract was tested. In the second model system, the cell membrane of osteoblast was used as the source for biological lipid. The results indicated that all strains were able to protect biological lipids from oxidation. The inhibition rates on cell membrane lipid peroxidation ranged from 22 to 37%. The effect of L. acidophilus and B. longum on inhibition of fluorescent tissue pigment accumulation was also obtained for osteoblastic cells. The inhibition rates on fluorescent tissue pigment accumulation ranged from 20 to 39%. The antioxidative effect of each milliliter of intracellular cell-free extract of L. acidophilus and B. longum was equivalent to 104-172 ppm of butylated hydroxytoluene (BHT). These results indicated that all strains demonstrated high antioxidative activity. The scavenging ability of lipid peroxidation products, tert-butyl hydroperoxide and malondialdehyde, was also evaluated. The results showed that L. acidophilus and B. longum were not able to scavenge the tert-butyl hydroperoxide. Nevertheless, malondialdehyde was scavenged well by these strains.  相似文献   

6.
Monosaccharides released by acid hydrolysis from paddy field soil, from the light and the heavy fraction of soil, front some plant fragment were determined using automated anio-exchange chromatography.

Between 5 and 12 per cent of the organic carbon was present as saccharides.

The monosaccharide composition of the different soils was very similar, in spite of differences in the absolute amount of saccharides present. The amount of the various monosaccharide in the whole soil was found to be in the order glucose»xylose galactose, mannose, arabinose rhamnose ribose.

The monoccharide composition of the soils showed a marked contrast to that of the rice ra8ment, and partially decomposed plant remains taken from the soil. Glucose, xylose, arabi-the predominant saccharides in the rice fragments and the plant remains, while the amounts of galactose, mannose, rhamnose were negligibly small.

It was found that the proportion of galactose, mannose, rhamnose and ribose in the heavy fraction Of soil was greater than that of glucose, xylose, and arabinose

The present observation was in agreement with the view that soil sauharides comprised Pentoses originates in plant materials.

The molar ratio of xylose to mannose was calculated to show the characteristics of the mono-saccharide composition of soils and some plant muerials.  相似文献   

7.
Antioxidative ability of lactic acid bacteria   总被引：24，自引：0，他引：24  
Nineteen strains of lactic acid bacteria were investigated for antioxidative activity. These includedLactobacillus acidophilus B, E, N1, 4356, LA-1, and Farr; Lactobacillus bulgaricus 12 278, 448, 449, Lb, 1006, and 11 842; Streptococcus thermophilus 821, MC, 573, 3641, and 19 987; and Bifidobacterium longum B6 and 15 708. Intracellular cell-free extract of all strains demonstrated antioxidative activity with inhibition rates of ascorbate autoxidation in the range of 7-12%. Antioxidative mechanisms including metal ion chelating ability, scavenge of reactive oxygen species, enzyme inhibition, and reducing activity of intracellular cell-free extract of lactic acid bacteria were studied. S. thermophilus 821 had the highest metal ion chelating ability for Fe(2+), and B. longum 15 708 showed the highest Cu(2+) chelating ability among the 19 strains tested. All strains demonstrated reactive oxygen species scavenging ability. L. acidophilus E showed the highest hydroxyl radical scavenging ability, and B. longum B6 had the best hydrogen peroxide scavenging ability. Reducing activity was also found in all strains. Most of the strains tested demonstrated excellent reducing activity. B. longum B6 showed the highest reducing activity among the 19 strains tested. In enzyme inhibition, superoxide dismutase activity was not found in these 19 strains, and the activity of superoxide dismutase was not induced when metal ion Mn(2+), Fe(2+), or Cu(2+)Zn(2+) was present.  相似文献   

8.
The cell wall materials (CWMs) from sweetpotato (Ipomoea batatas cv. Kokei 14), cassava (Manihot esculenta), and potato (Solanum tuberosum cv. Danshaku) and commercial sweetpotato fiber as well as their polysaccharide fractions were analyzed for sugar composition by the high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) method. The separation of arabinose and rhamnose, and xylose and mannose, by this method has been improved using a CarboPac PA 10 column. Pretreatment of the CWMs and cellulose fractions with 12 M H(2)SO(4) was required for complete hydrolysis to occur. Commercial sweetpotato fiber was found to be mainly composed of glucose (88.4%), but small amounts of other sugars were also detected. Among the root crops, sweetpotato CWM had the highest amount of pectin and galacturonic acid. Fucose was detected only in cassava CWM and its hemicellulose fraction, while galactose was present in the highest amount in potato CWM. Among the polysaccharide fractions, it was only in the hemicellulose fraction where significant differences in the sugar composition, especially in the galactose content, were observed among the root crops.  相似文献   

9.
Hemicelluloses (A and B) were isolated from an Indo-African hybrid variety of finger millet (ragi, Eleusine coracana) by extracting the starch-free residue with 10% sodium hydroxide under a continuous stream of nitrogen, and changes in their sugar composition during malting for 96 h were studied. Hemicellulose B, obtained in higher yield from both native (N) and malted (M) flours, was found to be completely soluble in water, richer in uronic acid, and more viscogenic than hemicelullose A. Fractional precipitation of hemicellulose B by ammonium sulfate resulted in four precipitable fractions (F-60, F-70, F-80, and F-100) and a nonprecipitable (NP) fraction varying in their yield and arabinose, xylose, galactose, and glucose contents. A progressive increase in the pentose-to-hexose ratio (P:H) from 0.42:1.0 in F-60 to 1.94:1.0 in NP was observed in native hemicellulose B fractions; however, in malted hemicellulose B the P:H ratio increased from 0.43:1.0 in F-60 to 1.56:1.0 in F-80 and then decreased to 1.13:1.0 in NP. The major fraction, F-70 (N, 44.5%; M, 38.5%), was separated into eight subfractions on DEAE-cellulose by successive elution with water, ammonium carbonate (AC) (0.1, 0.2, and 0.3 M AC), and sodium hydroxide (0.1 and 0.2 M) differing in their yield and neutral sugar composition. The purity of the major glucuronoarabinoxylan fraction (0.1 M AC eluted) was ascertained by Sepharose CL-4B, HPSEC, cellulose acetate, and capillary electrophoresis methods. A significant decrease in the molecular mass of arabinoxylan from 1200 to 1120 kDa upon malting for 96 h is an indication of cell wall degradation by the inducible cell wall degrading enzymes.  相似文献   

10.
The molecular basis by which human breast milk supports the development of a protective intestinal microbiome in infants is unknown. After lactose and lipids, human milk oligosaccharides (HMOs) are quantitatively the third largest and most diverse component of breast milk. In this work, glycomic profiling of HMO consumption by bifidobacteria using Fourier transform ion cyclotron resonance mass spectrometry reveals that one species, Bifidobacterium longum biovar infantis ATCC 15697, an isolate from the infant gut, preferentially consumes small mass oligosaccharides, representing 63.9% of the total HMOs available. These HMOs were detected in human breast milk at the onset and constantly through the first month of lactation by use of high performance liquid chromatography-chip time-of-flight mass spectrometry. Further characterization revealed that strain ATCC 15697 possesses both fucosidase and sialidase activities not present in the other tested strains. This work provides evidence that these small mass HMOs are selectively metabolized by select bifidobacterial strains and represent a potential new class of bioactive molecules functioning as prebiotics to facilitate a protective gut colonization in breast-fed newborns.  相似文献   

11.
土壤碳水化合物的研究   总被引：1，自引：0，他引：1  
碳水化合物是土壤有机质的组成分之一.一般认为,它在土壤良好结构的形成中起着重要的作用[1].根据Waksman和Stevens的“近似分析法",各种土壤的有机质中,“半纤维”的含量约在5-20%间,“纤维”的含量在0-5%间[2].但是这种方法并不能提供关于土壤碳水化合物本性方面的资料.近年来,借助于分离的方法,已经证明各种土壤中都有微生物来源的多糖存在.  相似文献   

12.
Celiac disease is an enteropathy caused by an abnormal immune response to cereal gluten proteins (gliadin). To unravel the possible role of the interactions between gliadin peptides and specific intestinal bacteria, the response of intestinal epithelial (Caco-2) cells to gliadin subjected to gastrointestinal digestion in the presence or absence of Bifidobacterium longum CECT 7347 has been studied. Changes in the proteome of Caco-2 cells were determined by 2DE and MALDI-TOF. Gliadins digested without B. longum altered the expression of a higher number of proteins than in the presence of the bacterium (21 versus 9), and these proteins were involved in disorganization of cell cytoskeleton, inflammation, and apoptosis. Gliadins digested in the presence of the bacterium influenced the production of proteins involved in calcium homeostasis and cell survival and function. Therefore, B. longum CECT 7347 might ameliorate gliadin toxicity and modify the responses of intestinal epithelial cells to the gliadin challenge.  相似文献   

13.
The identification of fish species in transformed food products is difficult because the existing methods are not adapted to heat-processed products containing more than one species. Using a common to all vertebrates region of the cytochrome b gene, we have developed a denaturing high-performance liquid chromatography (DHPLC) fingerprinting method, which allowed us to identify most of the species in commercial crab sticks. Whole fish and fillets were used for the creation of a library of referent DHPLC profiles. Crab sticks generated complex DHPLC profiles in which the number of contained fish species can be estimated by the number of major fluorescence peaks. The identity of some of the species was predicted by comparison of the peaks with the referent profiles, and others were identified after collection of the peak fractions, reamplification, and sequencing. DHPLC appears to be a quick and efficient method to analyze the species composition of complex heat-processed fish products.  相似文献   

14.
This study assessed specific peaks obtained by diffuse reflectance Fourier transform mid‐infrared spectroscopy (DRIFTS) for characterizing the soil organic matter (SOM) composition of a Haplic Chernozem. Soils were collected from the Static Fertilization Experiment, Bad Lauchstädt, Germany, during 5 years from the farmyard manure (FYM), mineral fertilizer (NPK), combination (FYM + NPK) and no fertilizer (Control) treatments. Soils were extracted with hot water (HWE), and fractionated by size and density. Bulk soil and fractions were analysed by DRIFTS. Peak areas at 2930, 1620, 1530 and 1159 cm?1 were selected as a range of organic functional groups (with limited mineral interference), integrated with a local baseline (corrected peak area) and each was divided by the summed area of the four peaks (relative peak area). Positive correlations between carbon (C) in fractions representing labile OM (<1.8 g cm?3, 1.8–2.0 g cm?3, CHWE) and the corrected peak area at 2930 cm?1 (3010–2800 cm?1) in the bulk soil indicated that this aliphatic peak corresponded to the more labile C compounds. Negative correlations between the same fractions and the corrected area of the predominantly aromatic peak at 1620 cm?1 (1660–1580 cm?1) in the bulk soil suggested a relationship with more stable SOM compounds. All relative peak areas were significantly affected by fertilizer treatment, with an increasing relative peak area at 2930 cm?1 in FYM compared with non‐FYM treatments. The ratio of the peaks at 1620 and 2930 cm?1 was positively correlated with the ratio of stable C (sum of C in >1.8 g cm?3 and clay fractions) to labile C (C content of <1.8 g cm?3 fraction) and thus taken as an indicator of SOM stability. The DRIFTS peak area method reflected changes in SOM quality and composition under long‐term management as measured by size and density fractionation, indicating heterogeneous chemical composition of the latter. Further, the DRIFTS analysis of undiluted soil samples can be used to assess SOM composition in small sample sets if specular reflection and mineral interferences are considered.  相似文献   

15.
Almond hulls and grape pomace are residues abundantly generated by agricultural industries, which could be processed to obtain bioactive products. To this purpose, crude ethanol extracts from both agricultural byproducts were attained and subsequently fractionated in order to obtain an organic/water fraction (FOW). Extracts and fractions were analyzed for antioxidant power and their phenolic components tentatively identified by HPLC-MS. Chromatographic peaks of almond hull extracts showed the occurrence of hydroxybenzoic and cinnamic acid derivatives, with minor presence of flavan-3-ols (ECG, EGCG), whereas the FOW fraction offered the additional presence of epicatechin (EC) and glycosylated flavonols. In the composition for extracts of white and red grape pomace several of these compounds were also detected but basically consisted of glycosylated flavonols (quercetin, kaempferol). As a difference between both grape pomaces, myricetin glycosyde was found in that from the red variety, whereas flavan-3-ols (EC, afzelechin) were only identified in white pomace. When their FOW fractions were analyzed, gallic acid and some hydroxybenzoic acids were additionally detected. Antioxidant activity was assessed by DPPH and TBARS assays. Almond hulls showed inhibition percentages lower than 50% in both assays, while the inhibition percentage ranged from 80% to 90% in pomace extracts. Red grape pomace extract was the most efficient antioxidant, with an EC50 value of 0.91 g/L for TBARS and 0.20 g/L for DPPH. Even appearing as two quite different vegetal matrixes, the composition of phenolics in grape pomace and almond hulls is quite similar, the main difference being the major occurrence of flavonols in grape pomace. This fact could presumably explain the lower antiradical activity of hull extracts.  相似文献   

16.
Mosquito larvicidal activity of Piper longum fruit-derived materials against the fourth-instar larvae of Aedes aegypti was examined. A crude methanol extract of P. longum fruits was found to be active against the larvae, and the hexane fraction of the methanol extract showed a strong larvicidal activity of 100% mortality. The biologically active component of P. longum fruits was characterized as pipernonaline by spectroscopic analyses. The LC(50) value of pipernonaline was 0.25 mg/L. The toxicity of pipernonaline is comparable to that of pirimiphos-methyl as a mosquito larvicide. In tests with available components derived from P. longum, no activity was observed with piperettine, piperine, or piperlongumine.  相似文献   

17.
Methylcellulose (MC) is ingested by humans in food and pharmaceutical formulations. The functional properties of MC like those of other linear polymers depend primarily on polymer length or molar mass for largely linear polymers. Although many studies in animals and humans have shown complete excretion of MC, in vitro human fecal fermentation studies indicate that MC can be degraded and presumably lose some of its functionality. In this study, MC polymer distribution in the feces from rats fed a diet containing 8% methylcellulose were compared to the fed MC. The water-soluble polymers in the feces were separated by a size exclusion chromatography (SEC) and the polymer distributions determined by multiple angle laser light scattering (MALLS). Detection of the fluorescent MC-calcofluor complex was used to confirm the identity of the eluting MC peak. All dietary MC was recovered in the feces. There is a small shift (P < 0.06) in the weight-averaged molecular weight of polymer distribution of MC extracted from the feces to 2.71 +/- 0.15 x 10(5) g/mol from 3.15 +/- 0.02 x 10(5) g/mol in the standard. There is also an increase in the polydispersity from 1.21 in the standard to 1.8 in the fecal extract. The distribution of the substituted methoxylated glucose monomers by gas chromatography also confirms the stability of MC fed to rats. The amount of actual hydrolysis is estimated to be about 0.1 glycosidic linkage/molecule. MC is not easily determined by standard dietary fiber methods, and SEC with MALLS and/or fluorescence may be a useful alternative.  相似文献   

18.
We have characterized a new immunostimulatory polysaccharide called Aloeride from commercial aloe vera (Aloe barbadensis) juice. Aloeride is between 4 and 7 million Da, and its glycosyl components include glucose (37.2%), galactose (23.9%), mannose (19.5%), and arabinose (10.3%). At 0.5 microg/mL Aloeride increased NF-kappa B directed luciferase expression in THP-1 human monocytic cells to levels 50% of those achieved by maximal concentrations (10 microg/mL) of LPS. Aloeride induced the expression of the mRNAs encoding IL-1beta and TNF-alpha to levels equal to those observed in cells maximally activated by LPS. Acemannan, the major carbohydrate component from aloe, used at 200 microg/mL in the macrophage assay resulted in negligible NF-kappa B activation. Analysis of acemannan and Aloeride using size-exclusion chromatography suggests that the low activity of acemannan is due to trace amounts of Aloeride. Although Aloeride comprises only 0.015% of the aloe juice dry weight, its potency for macrophage activation accounts fully for the activity of the crude juice.  相似文献   

19.
Galactooligosaccharides (GOS) obtained during the enzymatic hydrolysis of lactose contain large amounts of glucose, galactose, and unreacted lactose, which do not have prebiotic properties and increase the calorific value of the product. In this work, the isomerization of the GOS mixture by the action of sodium aluminate has been studied. During the reaction, lactose, glucose, and galactose were isomerized to lactulose, fructose, and tagatose, respectively, and in addition allolactose, 6-galactobiose, and 6'-galactosyl-lactose were also converted to the corresponding keto-sugars. The effect of time, temperature, and aluminate/initial lactose ratio has been studied. After 9 h at 40 degrees C and molar ratio aluminate/lactose 3:1, the isomerization yield was >60%, and the amount of final carbohydrates was close to 90% of the initial product. This process considerably decreases the amount of lactose, glucose, and galactose.  相似文献   

20.
Water extractable arabinogalactan-peptide (WE-AGP) isolated from white wheat flour was depolymerized enzymatically to liberate substrate for a galactose oxidase from Dactylium dendroides. A crude liquid pectolytic preparation from Aspergillus niger (p70) displayed activities capable of converting WE-AGP into a substrate for galactose oxidase. The most favorable substrate was observed when WE-AGP was not fully depolymerized into galactose and arabinose. alpha-L-Arabinofuranosidase B from A. niger was also able to produce substrate from WE-AGP; arabinofuranosidase-treated WE-AGP was a better substrate for galactose oxidase than galactose. Treatment by the crude p70 and purified enzymes showed that alpha-L-arabinofuranosidase was partly responsible for the production of substrate, whereas beta-galactosidase did not result in any substrate production or improve the effect of alpha-L-arabinofuranosidase. However, the positive effect of alpha-L-arabinofuranosidase was increased when p70 was added at the same level of arabinofuranosidase activity, suggesting that additional enzyme activities present in p70 were responsible for production of substrate for galactose oxidase.  相似文献   

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