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1.
Leathers TD Nunnally MS Côté GL 《Journal of industrial microbiology & biotechnology》2002,29(4):177-180
Four strains identified as Penicillium spp. were isolated from soil samples based on their capacity to modify the unique polysaccharide, alternan. Spores from these
isolates germinated in medium containing alternan and reduced the apparent molecular weight of alternan as determined by high-performance
size exclusion chromatography and viscometry. However, the fungi exhibited limited growth on alternan and did not consume
the substrate. The rheological properties of the modified alternan resembled those of commercial gum arabic. Thus, treatment
of native alternan with spores from these Penicillium spp. strains constitutes a simple bioconversion method to quantitatively produce novel and potentially useful modified alternan.
Journal of Industrial Microbiology & Biotechnology (2002) 29, 177–180 doi:10.1038/sj.jim.7000272
Received 14 February 2002/ Accepted in revised form 13 May 2002 相似文献
2.
Leuconostoc mesenteroides strain NRRL B-1355 produces the soluble exopolysaccharides alternan and dextran in planktonic cultures. Mutants of this strain
are available that are deficient in the production of alternan, dextran, or both. Our recent work demonstrated that biofilms
from mutant strains contained insoluble polysaccharides. We now find that the insoluble polysaccharides are composed of d-glucose polymers with contiguous sequences of α(1→3) and α(1→6) linkages. In addition, planktonic cultures of the wild type
also produce this insoluble mixture in association with the cell mass. This material is similar to the insoluble glucan matrix
known as mutan formed by cariogenic strains of streptococci. The production of insoluble mutan-like glucans may be more widespread
among Leuconostoc spp. than previously recognized.
Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard
of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also
be suitable. 相似文献
3.
Alternan is an unusual α-D-glucan containing alternating (1 → 3), (1 → 6) linkages that exhibits remarkable resistance to
enzymatic hydrolysis. The commercial potential of the polysaccharide may be enhanced by the ability to economically modify
the native form into fractions of varying molecular weight. By employing isolation procedures with covalently dyed alternan
as the substrate, several bacterial isolates that produced endohydrolytic activity were obtained in pure culture. The activity
was confirmed by decreases in viscosity and by direct examination of the hydrolysis products with thin layer chromatography.
Analysis of the hydrolysis products established that all isolates produced enzymes with identical alternan depolymerizing
activity, producing a cyclic tetrasaccharide as a major product. All alternanase activity was shown to be extracellularly
located. A single strain exhibited constitutive production of alternanase, while all other isolates required the presence
of alternan in the growth media for enzyme production. All isolates were phenotypically similar, produced heat-resistant spores,
and were tentatively identified as members of the genus Bacillus. 相似文献
4.
The enzyme alternanase, produced by Bacillus sp. NRRL B-21195, hydrolyzes alternan, a polysaccharide produced by certain strains of Leuconostoc mesenteroides that consists of glucose linked by alternating α(1→6), α(1→3) linkages. The main product of enzymatic hydrolysis by alternanase
is a novel cyclic tetrasaccharide of glucose that also has alternating linkages between the glucose moieties. An improved
purification scheme for alternanase has been developed that incorporates the use of isomaltosyl units linked to agarose for
selectively binding the alternanase enzyme. Bound enzyme was eluted with 0.5 M sodium chloride and was nearly pure after this
procedure. When followed by preparative isoelectric focusing, a single band of 117 kDa was measured when the purified protein
was analyzed by HPLC size-exclusion chromatography/multiangle light scattering. The purification procedure can be scaled to
permit large quantities of enzyme to be purified in high (36%) yield.
Electronic Publication 相似文献
5.
G L Cote J A Ahlgren M R Smith 《Journal of industrial microbiology & biotechnology》1999,23(1):656-660
Leuconostoc mesenteroides strain NRRL B-1355 produces two soluble extracellular α-D-glucans from sucrose: alternan and dextran. An unusual mutant strain derived from NRRL B-1355 has recently been isolated
which produces practically no soluble polysaccharide, but significant amounts of an insoluble D-glucan. Methylation analysis shows it contains linear (1→3) and (1→6) linkages as well as (1→2) and (1→3) branch linkages.
The insoluble glucan was partially digestible by endodextranase, giving rise to a series of oligosaccharides, a high-molecular
weight soluble fraction and an insoluble residue. Treatment of the soluble dextranase-limit fraction with an α(1→2) debranching
enzyme led to further dextranase susceptibility. Methylation, FTIR and NMR analyses of the dextranase-treated fractions indicate
a non-uniform structure with domains bearing similarities to L. mesenteroides strain NRRL B-1299 dextran and to insoluble streptococcal D-glucans.
Received 05 November 1998/ Accepted in revised form 31 March 1999 相似文献
6.
S. V. N. Vijayendra G. Palanivel S. Mahadevamma R. N. Tharanathan 《Archives of microbiology》2009,191(4):303-310
A heterofermentative Lactobacillus sp. CFR-2182 was isolated from dahi samples and it was found to produce 8.0 and 20.5 g/L heteropolysaccharide (HePS) in EPS medium (a simplified synthetic medium)
and modified MRS broth, respectively, after 72 h at 30°C. The total carbohydrate, reducing sugar and moisture contents of
the purified HePS were 74, 10.6 and 2 g, respectively, per 100 g on dry weight basis. The HePS produced in EPS medium had
glucose and mannose in 17:1 ratio. The HePS was non-gelling and non-film forming type. It was completely soluble in water
and 1 N sodium hydroxide solution. Gel permeation chromatography and HPLC analysis indicated considerable heterogeneity of
the HePS, having three fractions with molecular weights ranging from 3.3 × 104 to 1.32 × 106 Da. The enzymatic hydrolysis of the HePS with pullulanase and α-amylase [with α(1→4) linkage] indicated the presence of α(1→6)
and traces of α(1→4) linkages, respectively. NMR analysis of the EPS revealed unique chemical shifts. 相似文献
7.
T D Leathers J A Ahlgren G L Cote 《Journal of industrial microbiology & biotechnology》1997,18(4):278-283
Alternan is a unique α-D-glucan of potential commercial interest, produced by rare strains of Leuconostoc mesenteroides. Natural isolates that produce alternan, such as NRRL B-1355, also produce dextran as a troublesome contaminant. We previously
isolated mutants of strain NRRL B-1355 that are deficient in dextran production, including the highly stable strain NRRL
B-21138. In the current work, we mutagenized strain NRRL B-21138 and screened survivors for further alterations in production
of alternansucrase, the enzyme that catalyzes the synthesis of alternan from sucrose. Second generation mutants included
highly stable strain NRRL B-21297, which produced four-fold elevated levels of alternansucrase without an increase in the
proportion of dextransucrase activity. Such alternansucrase overproducing strains will facilitate studies of this enzyme,
and may become valuable for the enzymatic production of alternan. Another highly stable mutant strain, NRRL B-21414, grew
slowly on sucrose with negligible production of glucan or extracellular glucansucrase activity. This strain may prove useful
as an expression host for glucansucrase genes.
Received 30 July 1996/ Accepted in revised form 15 December 1996 相似文献
8.
An artificial fusion protein of Arthrobacter oxydans dextranase and Klebsiella pneumoniae α-amylase was constructed and expressed in Escherichia coli. Most of the expressed protein existed as an insoluble fraction, which was solubilized with urea. The purified fusion enzyme
electrophoretically migrated as a single protein band; M = 137 kDa, and exhibited activities of both dextranase (10.8 U mg−1) and amylase (7.1 U mg−1), which were lower than that of reference dextranase (13.3 U mg−1) and α-amylase (103 U mg−1). The fusion enzyme displayed bifunctional enzyme activity at pH 5–7 at 37°C. These attributes potentially make the fusion
enzyme more convenient for use in sugar processing than a two-enzyme system. 相似文献
9.
Leuconostoc mesenteroides strain NRRL B-1355 produces the soluble exopolysaccharides alternan and dextran in planktonic cultures. Mutants of this strain
are available that are deficient in the production of alternan, dextran, or both. Another mutant of NRRL B-1355, strain R1510,
produces an insoluble glucan in place of alternan and dextran. To test the effect of exopolysaccharide production on biofilm
formation, these strains were cultured in a biofilm reactor. All strains grew well as biofilms, with comparable cell densities,
including strain NRRL B-21414, which produces neither alternan nor dextran in planktonic cultures. However, the exopolysaccharide
phenotype clearly affected the appearance of the biofilms and the sloughed-off biofilm material produced by these biofilms.
For all strains, soluble glucansucrases and soluble polysaccharides produced by biofilm cultures appeared to be similar to
those produced by planktonic cultures. Biofilms from all strains also contained insoluble polysaccharides. Strain R1510 biofilms
contained an insoluble polysaccharide similar to that produced by planktonic cultures. For most other strains, the insoluble
biofilm polysaccharides resembled a mixture of alternan and dextran.
Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard
of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also
be suitable. 相似文献
10.
Marina Naoumkina Ivone Torres-Jerez Stacy Allen Ji He Patrick X Zhao Richard A Dixon Gregory D May 《BMC plant biology》2007,7(1):62
Background
Guar, Cyamopsis tetragonoloba (L.) Taub, is a member of the Leguminosae (Fabaceae) family and is economically the most important of the four species in the genus. The endosperm of guar seed is a rich source of mucilage or gum, which forms a viscous gel in cold water, and is used as an emulsifier, thickener and stabilizer in a wide range of foods and industrial applications. Guar gum is a galactomannan, consisting of a linear (1→4)-β-linked D-mannan backbone with single-unit, (1→6)-linked, α-D-galactopyranosyl side chains. To better understand regulation of guar seed development and galactomannan metabolism we created cDNA libraries and a resulting EST dataset from different developmental stages of guar seeds. 相似文献11.
A gene (arf) encoding an α-l-arabinofuranosidase (ARF) that hydrolyzes arabinose substituted on xylan was isolated from Penicillium sp. The gene was predicted to encode 339 amino acid residues showing 71–75% homology to GH family 54. E. coli expressed ARF showed optimal activity at 50°C and pH 5–6 on wheat arabinoxylan. The hydrolysis activities on oat spelt xylan
by ARF and xylanase were 1.67-fold higher than that of xylanase alone. The synergistic effects of ARF and commercial enzymes
(xylanase and cellulase) on popping-pretreated rice straw were 1.15–1.51-fold higher amounts of sugars released in the [ARF + xylanase + cellulase]
mixture than in the mixtures [ARF + xylanase], [ARF + cellulase], and [xylanase + cellulase]. Moreover, the liberation of
arabinose by ARF was enhanced 2.1–2.9-fold in a reaction with xylanase and cellulase as compared with [xylanase + cellulase]
and ARF alone. 相似文献
12.
Barbara Manconi Irene Messana Federica Maggiani Alessandra Olianas Mariagiuseppina Pellegrini Roberto Crnjar Massimo Castagnola Bruno Giardina Maria Teresa Sanna 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(8):971-983
Structural analysis of the hemoglobin (Hb) system of Delphinus delphis revealed a high globin multiplicity: HPLC–electrospray ionization-mass spectrometry (ESI-MS) analysis evidenced three major
β (β1 16,022 Da, β2 16,036 Da, β3 16,036 Da, labeled according to their progressive elution times) and two major α globins
(α1 15,345 Da, α2 15,329 Da). ESI-tandem mass and nucleotide sequence analyses showed that β2 globin differs from β1 for the
substitution Val126 → Leu, while β3 globin differs from β2 for the isobaric substitution Lys65 → Gln. The α2 globin differs
from the α1 for the substitution Ser15 → Ala. Anion-exchange chromatography allowed the separation of two Hb fractions and
HPLC–ESI-MS analysis revealed that the fraction with higher pI (HbI) contained β1, β2 and both the α globins, and the fraction with lower pI (HbII) contained β3 and both the α globins. Both D. delphis Hb fractions displayed a lower intrinsic oxygen affinity, a decreased effect of 2,3-BPG and a reduced cooperativity with
respect to human HbA0, with HbII showing the more pronounced differences. With respect to HbA0, either the substitution Proβ5 → Gly or the Proβ5 → Ala is present in all the cetacean β globins sequenced so far, and it
has been hypothesized that position 5 of β globins may have a role in the interaction with 2,3-BPG. Regarding the particularly
lowered cooperativity of HbII, it is interesting to observe that the variant human HbA, characterized by the substitution
Lysβ65 → Gln (HbJ-Cairo) has a decreased cooperativity with respect to HbA0. 相似文献
13.
M R Smith J C Zahnley R Y Wong R E Lundin J A Ahlgren 《Journal of industrial microbiology & biotechnology》1998,21(1-2):37-45
A mutant strain (R1510) of Leuconostoc mesenteroides B-1355 was isolated which synthesized primarily an insoluble polysaccharide and little soluble polysaccharide when grown
in sucrose-containing medium. Glucose or sucrose cultures of this strain produced a single intense band of GTF-1 activity
of 240 kDa on SDS gels, and a number of faint, smaller bands. Oligosaccharides synthesized by strain R1510 from methyl-α-D-glucoside
and sucrose included a trisaccharide whose structure contained an α(1→2) glucosidic linkage. This type of linkage has not
been seen before in any products from strain B-1355 or its mutant derivatives. The structure of the purified trisaccharide
was confirmed by 13C-nuclear magnetic resonance. The insoluble polysaccharide also contained α(1→2) branch linkages, as determined by methylation
analysis, showing that synthesis of the linkages was not peculiar to methyl-α-D-glucoside. GTF-1, which had been excised with
a razor blade from an SDS gel of a culture of the parent strain B-1355, produced the same trisaccharides as strain R1510,
showing that GTF-1 from the wild-type strain was the same as GTF-1 from strain R1510. Mutant strains resembling strain R1510,
but producing a single intense band of alternansucrase (200 kDa) instead of GTF-1 were also isolated, suggesting that mutations
may be generated which diminished the activities for any two of the three GTFs of strain B1355 relative to the third. Strain
R1554 produced a soluble form of alternansucrase, while strain R1588 produced a cell-associated form. The mechanism(s) by
which specific GTFs become associated with the cells of L. mesenteroides was not explored.
Received 12 May 1998/ Accepted in revised form 16 July 1998 相似文献
14.
Biochemical properties of a putative thermostable dextranase gene from Thermotoga lettingae TMO were determined in a recombinant protein (TLDex) expressed in Escherichia coli and purified to sevenfold apparent homogeneity. The 64-kDa protein displayed maximum activity at pH 4.3, and enzyme activity
was stable from pH 4.3–10. The optimal temperature was 55–60°C during 15 min incubation, and the half-life of the enzyme was
1.5 h at 65°C. The enzyme showed higher activity against α-(1 → 6) glucan and released isomaltose and isomaltotriose as main
products from dextran T2000. An unusual kinetic feature of TLDex was the negative cooperative behavior on the reaction of
dextran T2000 cleavage. Enzyme activity was not significantly affected by the presence of metal ions, except for the strong
inhibited by 1 mM Fe2+ and Ag2+. TLDex may prove useful as an enzyme for high temperature sugar milling processes. 相似文献
15.
Junpei Zhou Pengjun Shi Huoqing Huang Yanan Cao Kun Meng Peilong Yang Rui Zhang Xiaoyan Chen Bin Yao 《Applied microbiology and biotechnology》2010,88(6):1297-1309
The α-galactosidase gene, galA17, was cloned from Flavobacterium sp. TN17, a symbiotic bacterium isolated from the gut of Batocera horsfieldi larvae. The 2,205-bp full-length gene encodes a 734-residue polypeptide (GalA17) containing a putative 28-residue signal
peptide and a catalytic domain belonging to glycosyl hydrolase family 36 (GH 36). The deduced amino acid sequence of galA17 was most similar to a putative α-galactosidase from Pedobacter sp. BAL39 (EDM38577; 66.6% identity) and a characterized α-galactosidase from Carnobacterium piscicola BA (AAL27305; 30.1%). Phylogenetic analysis revealed that GalA17 was similar to GH 36 α-galactosidases from symbiotic bacteria
sharing two putative catalytic motifs, KWD and SDXXDXXXR, in which D480, S548, D549, and R556 were essential for α-galactosidase
activity based on site-directed mutagenesis. Purified recombinant GalA17 showed apparent optimal activity at pH 5.5 and 45°C;
exhibited strong resistance to digestion by trypsin, α-chymotrypsin, collagenase, and proteinase K; and efficiently hydrolyzed
several synthetic and natural substrates (p-nitrophenyl-α-d-galactopyranoside, stachyose, melibiose, raffinose, soybean meal, locust bean gum, and guar gum). 相似文献
16.
Yuichi Uno Sae Hashidume Osamu Kurita Takayuki Fujiwara Keiichi Nomura 《Acta Physiologiae Plantarum》2010,32(4):713-718
α-Mannosidase (EC 3.2.1.24) was purified from ‘Iseimo’, a native variety of Dioscorea opposita Thunb. Before purification, we investigated the composition of a viscous polysaccharide that interferes with column chromatography
procedures. The polysaccharide consisted mainly of mannose, and also contained uronic acid. We used the cationic detergent
cetylpyridinium chloride (CPC) to remove the polysaccharide. CPC treatment decreased viscosity without affecting α-mannosidase
activity. We purified α-mannosidase 2,650-fold. The optimal pH of the enzyme was 6.0 and the optimum temperature was 65°C.
The K
m value for p-nitrophenyl-α-d-mannopyranoside was 0.35 ± 0.03 mM. Activity was inhibited by swainsonine but not kifunensine. The enzyme cleaved α-1,2 linkages
preferentially to α-1,6 and α-1,3 linkages. The M
r of purified α-mannosidase was estimated to be 250–260 kDa by gel filtration and native-PAGE. Four polypeptides (86, 83, 80,
and 28 kDa) were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It is unclear whether the polypeptides
are encoded by one gene or multiple genes. However, N-terminal sequence analysis suggested that post-translational cleavage
and/or glycosylation resulted in the three large fragments, if these amino acids were encoded by the same gene. Homology searches
and characterization of the enzyme’s properties indicated that Iseimo α-mannosidase belongs to the glycoside hydrolase family
38 proteins, and to the Class II mannosidase group. 相似文献
17.
Clavel C Canales A Gupta G Santos JI Cañada FJ Penadés S Surolia A Jiménez-Barbero J 《Glycoconjugate journal》2007,24(8):449-464
The conformational and dynamic behaviour of three mannose containing oligosaccharides, a tetrasaccharide with α1→2, and α1→3,
and a penta and a heptasaccharide with α1→2, α1→3, and α1→6 linkages has been evaluated by molecular mechanics and dynamics
simulations and NMR spectroscopical methods. It is found that they display a fair amount of conformational freedom, with one
major and one minor conformation per glycosidic linkage. The evaluation of their recognition by banana lectin has also been
performed by STD NMR methods and a preliminary view of their putative interaction mode has been carried out by means of docking
procedures. 相似文献
18.
Dean E. Pearson 《Oecologia》2009,159(3):549-558
As primary producers, plants are known to influence higher trophic interactions by initiating food chains. However, as architects,
plants may bypass consumers to directly affect predators with important but underappreciated trophic ramifications. Invasion
of western North American grasslands by the perennial forb, spotted knapweed (Centaurea maculosa), has fundamentally altered the architecture of native grassland vegetation. Here, I use long-term monitoring, observational
studies, and field experiments to document how changes in vegetation architecture have affected native web spider populations
and predation rates. Native spiders that use vegetation as web substrates were collectively 38 times more abundant in C. maculosa-invaded grasslands than in uninvaded grasslands. This increase in spider abundance was accompanied by a large shift in web
spider community structure, driven primarily by the strong response of Dictyna spiders to C. maculosa invasion. Dictyna densities were 46–74 times higher in C. maculosa-invaded than native grasslands, a pattern that persisted over 6 years of monitoring. C. maculosa also altered Dictyna web building behavior and foraging success. Dictyna webs on C. maculosa were 2.9–4.0 times larger and generated 2.0–2.3 times higher total prey captures than webs on Achillea millefolium, their primary native substrate. Dictyna webs on C. maculosa also captured 4.2 times more large prey items, which are crucial for reproduction. As a result, Dictyna were nearly twice as likely to reproduce on C. maculosa substrates compared to native substrates. The overall outcome of C. maculosa invasion and its transformative effects on vegetation architecture on Dictyna density and web building behavior were to increase Dictyna predation on invertebrate prey ≥89 fold. These results indicate that invasive plants that change the architecture of native
vegetation can substantially impact native food webs via nontraditional plant → predator → consumer linkages. 相似文献
19.
G F Mahler R G Kok A Cordenons K J Hellingwerf B C Nudel 《Journal of industrial microbiology & biotechnology》2000,24(1):25-30
The effects of lactic acid, oleic acid, gum arabic and their mutual interactions, on the production of extracellular lipase
and the regulation of the expression of the lipase encoding gene (lipA) in Acinetobacter calcoaceticus were investigated. Formation of extracellular lipase was measured in culture supernatants of wild-type strain BD413 and expression
of the lipA gene was monitored in vivo with a chromosomal fusion of lipA to lacZ. At the level of lipA expression only oleic acid had a significant effect; it lowered expression. Neither gum arabic nor lactic acid had any effect
on lipA expression. On the other hand, the yield of extracellular lipase increased 2–5 times by the addition of gum arabic, possibly
due to the release of cell surface-bound lipase. An interaction between oleic acid and lactic acid was also detected. Journal of Industrial Microbiology & Biotechnology (2000) 24, 25–30.
Received 03 May 1999/ Accepted in revised form 04 September 1999 相似文献
20.
Haiyan Sun Xiangyang Ge Weiguo Zhang 《World journal of microbiology & biotechnology》2007,23(5):603-613
Penicillium sp. X−1, isolated from decayed raw corn, produced high level of raw-starch-digesting glucoamylase (RSDG) under solid state
fermentation (SSF). Maximum enzyme yield of 306.2 U g−1 dry mouldy bran (DMB) was obtained after 36 h of culture upon optimized production. The enzyme could hydrolyse both small
and large granule starches but did not adsorb on raw starch. The enzyme exhibited maximum activity at 65°C and pH 6.5, which
provided an opportunity of synergism with α-amylase. It significantly hydrolysed 15% (w/v) raw corn starch slurry in synergism
with the commercial α-amylase and a degree of hydrolysis of 92.4% was obtained after 2 h of incubation. 相似文献