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1.
Mareková M Lauková A Skaugen M Nes I 《Journal of industrial microbiology & biotechnology》2007,34(8):533-537
The new bacteriocin, termed enterocin M, produced by Enterococcus faecium AL 41 showed a wide spectrum of inhibitory activity against the indicator organisms from different sources. It was purified
by (NH4)2SO4 precipitation, cation-exchange chromatography and reverse phase chromatography (FPLC). The purified peptide was sequenced
by N-terminal amino acid Edman degradation and a mass spectrometry analysis was performed. By combining the data obtained
from amino acid sequence (39 N-terminal amino acid residues was determined) and the molecular weight (determined to be 4 628 Da)
it was concluded that the purified enterocin M is a new bacteriocin, which is very similar to enterocin P. However, its molecular
weight is different from enterocin P (4 701.25). Of the first 39 N-terminal residues of enterocin M, valine was found in position
20 and a lysine in position 35, while enterocin P has tryptophane residues in these positions. 相似文献
2.
Kjellmaniella crassifolia, the edible macro-brown alga in Japan contained nearly 27% of alginates of which nearly 7% was extractable from the fronds with boiling water for 6 h and the residual alginates in the frond were almost exhaustively extracted with a dilute alkali at 60 °C for 6 h. The alginates dissolved in all these extracts with both boiling water and dilute alkali were purified by fractionation with MgCl2 and alcohol.The content of MM blocks in the boiling water-soluble alginate sample increased remarkably during heating for 6 h while that of GG blocks from the same sample decreased. In contrast, MM blocks in the alkali-soluble alginate sample decreased during 6 h heating while GG blocks continued to increase. Since the amounts of MG blocks showed slight fluctation, the M:G ratio of alginates extracted with boiling water increased towards the end of extraction whereas the reverse is true for the alkali-soluble alginates. 相似文献
3.
d-Ribulose 1,5-diphosphate carboxylase from extracts of the unicellular blue-green alga Aphanocapsa 6308 has been purified by ammonium sulphate precipitation and linear sucrose density gradient centrifugation. The molecular weight was estimated to be 525 000 and the enzyme consisted of two types of sub-unit of molecular weights 51 000 and 15 000. The small sub-units were not detected after purification involving acid precipitation but were observed if the acid precipitation step was omitted. The Michaelis constants for Mg2+ and CO2, when tested under air, were 0.35 mM and 0.071 mM respectively. Oxygen acted as a competitive inhibitor with respect to CO2, suggesting that the enzyme also acts as an oxygenase. This was confirmed by measuring ribulose diphosphate-dependent O2 uptake. A 1:1 stoichiometry between ribulose diphosphate utilization and O2 consumption was observed. 6-Phosphogluconate inhibited carboxylase activity both at high (20 mM) and low (1 mM) bicarbonate concentrations. The data are compared with the properties of ribulose diphosphate carboxylase from other autotrophic prokaryotes and from chloroplasts.Abbreviations RuDP
d-Ribulose 1,5-diphosphate
- EDTA
ethylene diamine tetraacetic acid
- GSH
reduced glutathione
- SDS
sodium dodecyl sulphate
- 6PGluc
6-phosphogluconate
- STB
supplemented Tris buffer 相似文献
4.
Ahlert Schmidt 《Planta》1981,152(2):101-104
Fructose-1,6-bisphosphatase was isolated from the cyanobacterium Synechococcus 6301 by acid precipitation, ammonium-sulfate fractionation, and Sephadex gel chromatography. The purified enzyme needed thiols and MgCl2 for activity. The following Km-values were obtained: a) for fructose-1,6-bisphosphate: 1.7 mM; b) for MgCl2: 12.5 mM; c) for dithiocrythritol: 0,56 mM; d) for glutathione: 14 mM; e) for mercaptoethanol: 22 mM; f) for cysteine: 50 mM. Thioredoxin B isolated from this organism will activate this fructose-1,6-bisphosphatase. The Km of thioredoxin B for this fructose-1,6-bisphosphatase was determined to be 1.7 M, endicotiy that thioredoxin might activate the fructose-1,6-bisphosphatase in Synechococcus in vivo. 相似文献
5.
The alyPEEC gene encoding alginate lyase from marine bacterium Pseudoalteromonas elyakovii IAM 14594 was subcloned into pBAD24 with arabinose promoter and sequenced, and overexpressed in TOP10 strain of E. coli after arabinose induction. Expression levels of alyPEEC gene in E. coli cells were over 39.6-fold higher than those in P. elyakovii IAM 14594 cells. The molecular mass of purified alginate lyase from the engineered E. coli cells was estimated to be 32.0 kDa. Optimum pH and temperature of the alginate lyase activity were 7.0 and 30 °C, respectively.
The enzyme was unstable on heating and in acidic and alkaline solution. The enzyme activity was stimulated by the MgCl2, NaCl, KCl, CaCl2, BaCl2 and MnCl2, but was inhibited by the addition of 1.0 mM of EGTA, EDTA, SDS, ZnSO4, AgNO3, and CoCl2. All the alginate, polyM and polyG could be converted into oligosaccharides with more than tetrasaccharides by the purified
recombinant alginate lyase, suggesting that the recombinant alginate lyase produced by the engineered E. coli has highly potential application in seaweed genetics, food and pharmaceutical industries. 相似文献
6.
Ci Su-Qin Chen Shan Dong-Bo Liu Hong-Mei Xia 《World journal of microbiology & biotechnology》2006,22(7):729-735
Summary
Penicillium sp. DS9713a-01 was obtained by ultraviolet (u.v.) light mutagenesis from the Penicillium sp. DS9713a which can degrade poly (3-hydroxybutyrate) (PHB). The enzymatic activity of DS9713a-01 was 97% higher than that
of the wild-type strain. The DS9713a-01 mutant could completely degrade PHB films in 5 days; however, the wild-type strain
achieved only 61% at the same time. The extracellular PHB depolymerase was purified from the culture medium containing PHB
as the sole carbon source by filtration, ammonium sulfate precipitation and chromatography on Sepharose CL-6B. The molecular
weight of the PHB depolymerase was about 15.1kDa determined by SDS-polyacrylamide gel electrophoresis. The optimum activity
of the PHB depolymerase was observed at pH 8.6 and 50 °C. The enzyme was stable at temperatures below 37 °C and in the pH
range from 8.0 to 9.2. The activity of PHB depolymerase could be activated or inhibited by some metal ions. The apparent K
m
value was 0.164 mg ml−1. Mass spectrometric analysis of the water-soluble products after enzymatic degradation revealed that the primary product
was the monomer, 3-hydroxybutyric acid. 相似文献
7.
Alginate extracted from the macroalgae Sargassum sinicola was used as the raw material for co-immobilization of the microalgae Chlorella sorokiniana and growth-promoting bacterium Azospirillum brasilense for wastewater treatment and as an inoculant carrier of A. brasilense for plant growth promotion. The composition, structure, viscosity, color, and phenolic compound content of the alginate were
analyzed and compared with commercially available alginate produced from the macroalgae Macrocystis pyrifera. From 1H NMR analysis of alginate, S. sinicola was found to have more guluronic acid (F
G=0.64) than it had mannuronic acid (F
M=0.38) and had a viscosity of 13.5 m Pa s compared to 50 m Pa s for M. pyrifera. The S. sinicola alginate had dark brown color, reducing light penetration, with more phenolic compounds than M. pyrifera alginate. Nonetheless, growth of C. sorokiniana and A. brasilense in S. sinicola alginate was not significantly different than the growth in M. pyrifera alginate beads. Nutrient removal from wastewater by the co-immobilized microorganisms was similar for both types of alginate
beads, and so was the growth enhancement of tomato plants inoculated with microbeads containing A. brasilense. This study shows the potential use of S. sinicola alginate as a raw material for cell immobilization for wastewater treatment and plant growth promotion. 相似文献
8.
Pamela M. Reilly Dr. Palmer Rogers 《Journal of industrial microbiology & biotechnology》1987,1(5):329-334
Summary Conditions that allow regeneration of cells fromClostridium acetobutylicum strain B643 protoplasts were studied. Protoplast formation and stabilization in minimal media with 50 mM CaCl2, 50 mM MgCl2 and 0.3 M sucrose were crucial to subsequent regeneration on soft yeast extract agar containing 25 mM CaCl2 and 25 mM MgCl2. A regeneration frequency of 8–25% was consistently obtained. 相似文献
9.
A simple procedure for the isolation of bacterial lipopolysaccharides was developed. The method consists of the following three steps; recovery of lipopolysaccharides in an insoluble form together with denatured proteins in a hot MgCl2-Triton X-100 solution (step 1), solubilization with EDTA-Triton X-100 (step 2) and precipitation with MgCl2 (step 3). A good yield of lipopolysaccharides was obtained with most of the Pseudomonas strains tested. Although the yield was lower with strains belonging to Salmonella and Escherichia, irrespective of whether they are smooth-type or rough-type strains, the amounts obtained from 100 mg of cells as dry weight were sufficient for detailed chemical characterization. The gel-electrophoretic profiles of the lipopolysaccharides prepared by the present method were essentially the same as those of the lipopolysaccharides prepared by the conventional phenol-water method. The method allowed us to prepare lipopolysac-charides from a large number of bacterial strains in one day. 相似文献
10.
Trehalose-6-phosphate synthase, catalyzing the reaction between UDP-glucose and glucose 6-phosphate and forming trehalose 6-phosphate, was isolated and partially purified (30-fold) from the phototrophic, haloalkaliphilic bacteriumEctothiorhodospira halochloris. The activity is stabilized by 20mM MgCl2, 50mM NaCe and 2M glycine betaine. The molecular weight was 63000.The enriched enzyme had a MgCl2 optimum at 3–6mM, a pH optimum at 7.5 (in Tris-HCl buffer) and a temperature optimum at 50°C. The Km-values were 1.5×10–3M for UDP-glucose and 2×10–3M for glucose 6-phosphate. The enzyme showed a salinity dependence with optimal concentrations between 100 and 300mM salt. Higher concentrations of salt resulted in a decrease in activity. In the presence of inhibitory salt concentrations the compatible solute glycine betaine had a protective effect with a maximum between 0.5 and 2.0M. 相似文献
11.
Glycerol formation ofDunaliella cells in non-growing media was investigated.Dunaliella tertiolecta andD. bioculata grew well in a NaCl medium but not at all in a LiCl or a MgCl2 medium. When the cells originally suspended in a medium containing 0.5 M NaCl were transferred to media which contained one
of 1 M NaCl, 1 M LiCl or 0.7 M MgCl2, the intracellular glycerol content increased.D. tertiolecta cultured in either a 1 M LiCl or a 0.7 M MgCl2 medium did not multiply, but maintained abilities to evolve O2 in the light and absorb O2 in thedark even after about a 5 day culture. From these results, it can be concluded that the halotolerance ofDunaliella to different kinds of salts is not directly related to osmoregulation by the glycerol formation. 相似文献
12.
Sugar constituents of fucose-containing polysaccharides from various Japanese brown algae 总被引:3,自引:0,他引:3
Sugar constituents of the fucose-containing polysaccharides (FCPs) from 21 species of brown algae were analyzed. FCPs were extracted with hot water (100 °C, 4 h), separated by precipitation with 20% (v:v) ethanol in the presence of 0.05 M MgCl2 to remove contaminating soluble alginate, and purified by DEAE-Sephadex column chromatography. The samples were hydrolyzed with HCI, and neutral sugar and uronic acid were separated by anion exchange chromatography. Their amounts were determined by gas-liquid chromatography. The neutral sugars in the FCPs from Ishige okamurae, Laminaria ochotensis, Myelophycus simplex, Padina arborescens and Sargassum thunbergii all contained arabinose, fucose, galactose, glucose, mannose, rhamnose and xylose residues. The FCPs from Ishige okamurae, Padina arborescens, Sargassum hemiphyllum, S. patents and S. sagamianum contained the four uronic acids, galacturonic acid, glucuronic acid, guluronic acid and mannuronic acid. 相似文献
13.
Lin Xiao Feng Han Zhao Yang Xin-zhi Lu Wen-gong Yu 《World journal of microbiology & biotechnology》2006,22(1):81-88
Summary To exploit alginate lyase which could degrade bacterial alginates, degenerate PCR and long range-inverse PCR (LR-IPCR) were
used to isolate alginate lyase genes from soil bacteria. Gene algL, an alginate lyase-encoding gene from Pseudomonas sp. QD03 was cloned, and it was composed of a 1122 bp open reading frame (ORF) encoding 373 amino acid residues with the
calculated molecular mass of 42.2 kDa. The deduced protein had a potential N-terminal signal peptide of 20 amino acid residues
that was consistent with its proposed periplasmic location. Gene algL was expressed in pET24a (+)/E. coli BL21 (DE3) system. The recombinant AlgL was purified to electrophoretic homogeneity using affinity chromatography. The molecular
weight of AlgL was estimated to be 42.8 kDa by SDS-PAGE. AlgL exhibited maximal activity at pH 7.5 and 37 °C. Na+, K+, Ca2+ and Ba2+ significantly enhanced the activity of AlgL. AlgL could degrade alginate and mannuronate blocks, but hardly degrade guluronate
blocks. In particular, AlgL could degrade acetylated alginate of Pseudomonas aeruginosa FRD1 (approximately 0.54 mol of O-acetyl group per mol of alginate). It might be possible to use alginate lyase AlgL as an adjuvant therapeutic medicine for
the treatment of disease associated with P. aeruginosa infection. 相似文献
14.
Garbayo I Vílchez C Vega JM Nava-Saucedo JE Barbotin JN 《Biotechnology letters》2004,26(23):1825-1827
Streptococcus thermophilusand Lactobacillus bulgaricus were co-immobilized in different systems with varying calcium (0.1–1.5M) and alginate (1–2<><>, w/v) concentrations. Highest lactic acid production was 35 g l1 when both bacteria were in high viscosity beads (1<><>, w/v alginate) hardened in 0.1 M CaCl2 .The gel bead composition affected size and distribution of entrapped lactic acid bacteria. 相似文献
15.
In this study, three alginate fractions with different molecular weights and ratios of mannuronic acid (M) to guluronic acid
(G) were prepared by enzymatic hydrolysis and ultrafiltration to assess the antioxidant property of alginates from Laminaria japonica with molecular weight below 10 kDa. The antioxidant properties of different molecular weight alginates were evaluated by
determining the scavenging abilities on superoxide, hydroxyl, and hypochlorous acid and inhibitory effect on Fe2+-induced lipid peroxidation in yolk homogenate. The results showed that low molecular weight alginates exhibited high scavenging
capacities on superoxide, hydroxyl, and hypochlorous acid radicals and good inhibition of Fe2+-induced lipid peroxidation in yolk. By comparison, alginate A1 with molecular weight below 1 kDa and M/G of 1.84 had better
scavenging activity on superoxide, hydroxyl, and hypochlorous acid radicals in vitro than A2 (1–6 kDa), A3 (6–10 kDa), ascorbic
acid, and carnosine. With similar M/G ratio, A2 exhibited better antioxidant activity on superoxide and hypochlorous acid
radicals than A3. However, fraction A3 with molecular weight of 6–10 kDa exhibited higher inhibitory ability on lipid peroxidation
in yolk in vitro than A1 and A2. The results indicated that molecular weight played a more important role than M/G ratio on
alginate to determine the antioxidant ability. By comparison, low molecular weight alginates composed of guluronic acid and
mannuronic acid exhibited better antioxidant ability on oxygen free radicals than sulfated polysaccharides from L. japonica in our previous study and represent a good source of marine polysaccharide with potential application as natural antioxidant. 相似文献
16.
Mucins are the major glycoprotein secretions of mucous glands and display important functions in amphibian skin such as regulation
of water homeostasis and mechanical and chemical protection. In the present study, we evaluated the glycoconjugate contents
of developing mucous glands on dorsal regions of metamorphosing Bufo viridis (Amphibia: Anura) tadpoles using an alcian blue-PAS panel and lectin histochemistry. All the conical cells of mucous glands
showed weak positivity for alcian blue in 0.025 M MgCl2 at pH 5.7 but only a few cells were positive for 0.3 M MgCl2 at the same pH. In addition, all the conical cells of mucous glands were negative for alcian blue at pH 2.5. In lectin histochemistry,
conical cells reacted strongly with Galanthus nivalis agglutinin (GNA), Datura stramonium agglutinin (DSA) and peanut agglutinin (PNA), weakly with Maackia amurensis leucoagglutinin (MAL). These results suggest that they express predominantly mannose, galactose and partially α(2→3)-linked sialic acid containing glycoconjugates. We concluded that dorsal mucous glands of metamorphosing Bufo viridis tadpoles contain at least two different conical cell types and glycoconjugate heterogeneity of mucous glands may be related
with different functions of mucins. 相似文献
17.
To help identify components of the blue-light photoreceptor system for phototropism in Phycomyces blakesleeanus Bgff., proteins from a microsomal fraction obtained from synchronous sporangiophores were studied. By two-dimensional gel electrophoresis, two proteins (FP1, FP2) with covalently bound flavins were found. FP1 has a molecular weight of 71 000 and an isoelectric point of 6.6; FP2 has a molecular weight of 59 000 and an isoelectric point of 6.5. These flavoproteins were purified by column chromatography and gel filtration while assaying for flavins by fluorescence. The relative concentrations of FP1 and FP2 were affected by light applied during growth. These flavoproteins are likely components of the blue-light photoreceptor complex mediating phototropism in Phycomyces.Abbreviations 10 k pellet
10 000-g pellet
- 100 k pellet
100 000-g pellet
- FP1, FP2
proteins with covalently bound flavins having molecular weights of 71 000 and 59 000 and isoelectric points of 6.6 and 6.5, respectively 相似文献
18.
A pyruvate, orthophosphate dikinase (EC 2.7.9.1) has been isolated from Acetobacter aceti grown on pyruvate as the only source of carbon and energy. The enzyme was purified 65-fold, and its molecular weight was determined to be about 330,000 by gel filtration.The optimum pH was 8.0 in the forward direction [phosphoenolpyruvate (PEP) formation] and 7.1 for the backward reaction (pyruvate production). In both directions Mg2+ was required (forward K
m
1.70 mM; reverse K
m
0.87 mM) and no other divalent cation was able to replace it. The K
m
values for pyruvate, ATP, and Pi were 27 M, 0.20 mM, and 0.83 mM, respectively, in the forward direction. The K
m
values for PEP, AMP, and PPi were 0.13 mM, 6 M, and 62 M, respectively, for the reverse reaction. The substrate-product pairs pyruvate-PEP, ATP-AMP, Pi-PPi were competitive inhibitors to each other in both directions. These product inhibition studies suggest for the enzyme from A. aceti nonclassical three-site Tri (Uni Uni) Ping-Pong kinetics.Abbreviations PEP
phosphoenolpyruvate
- OAA
oxaloacetate
- MW
molecular weight
- SDS
sodium dodecyl sulphate
- TEMG buffer
50 mM Tris-HCl, pH 7.5, 1 mM EDTA, 5 mM MgCl2, 1 mM glutathione 相似文献
19.
Toshio Miyazaki Toshiro Yadomae Takayoshi Terui Haruki Yamada Terukichi Kikuchi 《Biochimica et Biophysica Acta (BBA)/General Subjects》1975,385(2)
A water-soluble glucuronan “protuberic acid”, [α]d22 −83.6° and purified from Kobayashia Nipponica, and its physicochemical properties were investigated.The purified protuberic acid was homogeneous as shown by zone electrophoresis, gel filtration over Sepharose 4B, and ultracentrifugation. The sedimentation coefficient was 1.8 S and its intrinsic viscosity was 1.1 dl/g. By gel filtration the molecular weight was estimated to be about 170 000. The results of periodate oxidation, methylation analysis, and partial acid hydrolysis indicated that this acidic polysaccharide has a linear structure of mainly 1,4-linkages and containing an acid-labile linkage. Reduced protuberic acid, [α]d22 −44°, is also described. 相似文献
20.
Tryptophan decarboxylase from Catharanthus roseus cell suspension cultures: purification,molecular and kinetic data of the homogenous protein 总被引:2,自引:0,他引:2
The purification of tryptophan decarboxylase from Catharanthus roseus (TDC, E.C.:4.1.1.27), to apparent homogeneity, is described. The enzyme represents a soluble protein with a molecular weight of 115 000±3 000, consisting of 2 identical subunits of 54 000±1 000. The pI was estimated to be 5.9 and the Km for L-tryptophan was found to be 7.5×10-5 M. Phenylalanine, tyrosine and DOPA were not decarboxylated by tryptophan decarboxylase from Catharanthus cells. Similar to the aromatic amino acid decarboxylase from hog kidney the enzyme does not appear to be obligatorily dependent on exogenously supplied pyridoxal phosphate, as it seems to contain a certain amount of this cofactor. The average percentage of TDC in the cells was found to be 0.002% in the growth medium while the level increased up to 0.03% when indole alkaloid biosynthesis was induced. The role of the protein as a bottleneck enzyme of indole alkaloid biosynthesis is discussed. 相似文献