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51.
52.
The entire amino acid sequence of bifunctional alginate lyase from Pseudoalteromonas sp. strain No. 272 were determined by two approaches, Edman degradation of the peptides obtained from protease digestion of the enzyme protein and analysis of PCR products of the structural gene. The former resulted in incomplete amino acid sequence in the entire sequence, due to lacking of the proper peptides from the protease digestion. To compensate for this lack of sequences we applied the method of PCR of the structural gene that was initially elucidated from the primers designed from N- and C-terminal amino acid sequences of the enzyme. The results of the amino acid sequences from these two approaches showed good agreement. The enzyme consisted of 233 amino acid residues with a molecular mass of 25,549.5, including the sole W and cystine residue. The sequence homology search among the other alginate lyases from different origins indicated that they were very weakly homologous, with the exception of the sequence homology (80.3%) of Pseudoalteromonas elyakovii alginate lyase. The consensus sequence, YFKhG + Y-Q (Wong, T. Y., Preston, L. A., and Schiller, N. L. 2000. Annu. Rev. Microbiol.
54: 289–340) in the C-terminal regions was conserved. The kinetic analyses of chemical modification of some amino acid residues of the enzyme showed that W, K, and Y appeared to be important in the enzyme function. 相似文献
53.
Biodegradation of polyphenols with immobilized Candida tropicalis under metabolic induction 总被引:11,自引:0,他引:11
Ettayebi K Errachidi F Jamai L Tahri-Jouti MA Sendide K Ettayebi M 《FEMS microbiology letters》2003,226(2):215-219
During olive oil production, large quantities of olive mill wastewater (OMW) are produced. This wastewater material, containing a high level of phenolic compounds, poses a serious environmental problem in almost all Mediterranean countries. Candida tropicalis YMEC14 was used as an extremophile strain to design an aerobic biotreatment process to detoxify OMW and reduce its polluting organic load. The process was enhanced by directing yeast metabolism towards biodegradation pathways using hexadecane as co-metabolite and by immobilizing yeast cells in calcium alginate beads. Under immobilization conditions, C. tropicalis YMEC14 grown at 40 degrees C in OMW supplemented with hexadecane resulted in 69.7%, 69.2% and 55.3% reduction of chemical oxygen demand, monophenols and polyphenols, respectively, after a 24-h fermentation cycle. 相似文献
54.
Calcium alginate entrapment of the yeast Rhodosporidium toruloides for the kinetic resolution of 1,2-epoxyoctane 总被引:1,自引:0,他引:1
Resting cells of the yeast Rhodosporidium toruloides (UOFS Y-0471) were immobilised in calcium alginate beads for the enantioselective kinetic resolution of racemic-1,2-epoxyoctane. The initial activity exhibited by immobilised cells was almost 50% lower than that of the free counterpart but was extremely stable when compared to the free cells. The concentration of the immobilised biomass had no effect on apparent enzyme activity but did lead to a decrease in single cell activity. An increase in both the alginate and CaCl2 concentrations used for bead preparation led to a decrease in enzyme stability. An increase in the alginate concentration led to an increase in bead diameter. The stoichiometric equation for cross-linking of alginate was only obeyed when CaCl2 concentrations higher than 0.4 M were utilised for bead preparation. 相似文献
55.
Calcium-alginate beads were found to bind a variety of enzymes in a nonspecific fashion. However, alpha amylases from porcine pancreas, Bacillus subtilis (BAN 240L) and wheat germ bound at a significant level and B. subtilis and wheat germ amylases could be eluted with 1M maltose. The wheat germ alpha amylase could be purified 45 fold with 70% recovery. The SDS - PAGE pattern showed significant purification by this single step strategy. 相似文献
56.
K D Chapatwala G R V Babu O K Vijaya K P Kumar J H Wolfram 《Journal of industrial microbiology & biotechnology》1998,20(1):28-33
Pseudomonas putida utilizes cyanide as the sole source of carbon and nitrogen. Agar, alginate, and carrageenan were screened as the encapsulating
matrices for P. putida. Alginate-immobilized cells of P. putida degraded sodium cyanide (NaCN) more efficiently than non-immobilized cells or cells immobilized in agar or carrageenan. The
end products of biodegradation of cyanide were identified as ammonia (NH3) and carbon dioxide (CO2). These products changed the medium pH. In bioreactors, the rate of cyanide degradation increased with an increase in the
rate of aeration. Maximum utilization of cyanide was observed at 200 ml min−1 of aeration. Immobilized cells of P. putida degraded cyanides, cyanates and thiocyanates to NH3 and CO2. Use of Na[14C]-CN showed that 70% of carbon of Na[14C]-CN was converted into 14CO2 and only 10% was associated with the cell biomass. The substrate-dependent kinetics indicated that the K
m and V
max values of P. putida for the substrate, NaCN were 14 mM and 29 nmol of oxygen consumed mg protein−1 min−1 respectively.
Received 29 January 1996/ Accepted in revised form 19 September 1997 相似文献
57.
Promoting extracellular matrix remodeling via ascorbic acid enhances the survival of primary ovarian follicles encapsulated in alginate hydrogels
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58.
Shu‐Jyuan Yang Szu‐Min Chang Kun‐Che Tsai Wen‐Shiang Chen Feng‐Huei Lin Ming‐Jium Shieh 《The journal of gene medicine》2010,12(2):168-179
Background
Gene therapy has been used to treat a variety of health problems, but transfection inefficiency and the lack of safe vectors have limited clinical progress. Fabrication of a vector that is safe and has high transfection efficiency is crucial for the development of successful gene therapy. The present study aimed to synthesize chitosan‐alginate nanoparticles that can be used as carriers of the pAcGFP1‐C1 plasmid and to use these nanoparticles with an ultrasound protocol to achieve high efficiency gene transfection.Methods
Chitosan was complexed with alginate and the pAcGFP1‐C1 plasmid at different charge ratios to create chitosan‐alginate‐DNA nanoparticles (CADNs). The average particle size and loading efficiency were measured. Plasmid DNA retardation and integrity were analysed on 1% agarose gels. The effect of CADNs and ultrasound on the efficiency of transfection of cells and subcutaneous tumors was evaluated.Results
In the CADNs, the average size of incorporated plasmid DNA was 600–650 nm and the loading efficiency was greater than 90%. On the basis of the results of the plasmid DNA protection test, CADNs could protect the transgene from DNase I degradation. The transgene product expression could be enhanced efficiently if cells or tumor tissues were first given CADNs and then treated with ultrasound.Conclusions
The use of CADNs combined with an ultrasound regimen is a promising method for safe and effective gene therapy. Copyright © 2009 John Wiley & Sons, Ltd.59.
Protoplasts isolated from cell suspension culture of Phalaenopsis “Wataboushi” were cultured by (a) embedding in gellan gum-solidified hormone-free 1/2 New Dogashima medium (1/2 NDM) containing
0.44 M sorbitol, 0.06 M sucrose and 0.1 g/l l-glutamine (standard method) and (b) beads method using beads of gellan gum or sodium alginate as the gelling agents which
were surrounded by liquid NDM. Although, the two beads methods gave less frequency of initial protoplast division than the
standard method, the former finally resulted in higher frequency of microcolony formation than the latter. The highest frequency
of microcolony formation (23%) was obtained when protoplasts were embedded in 1% Ca-alginate beads and subcultured every two
weeks by replacing the surrounding liquid culture medium with a decrease in sorbitol concentration by 0.1 M. Colonies visible
to the naked eyes were observed within 2 months of culture and the regenerated calluses were transferred onto hormone-free
NDM supplemented with 10 g/l maltose and 0.3% (w/v) gellan gum, on which PLBs were formed and proliferated profusely. The
PLBs were regenerated into plantlets after changing the carbon source to 10 g/l sorbitol and successfully acclimatized to
greenhouse conditions. 相似文献
60.
A multiple-unit-type oral floating dosage form (FDF) of 5-fluorouracil (5-FU) was developed to prolong gastric residence time,
target stomach cancer, and increase drug bioavailability. The floating bead formulations were prepared by dispersing 5-FU
together with calcium carbonate into a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping
the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as alginate undergoes ionotropic
gelation by calcium ions and carbon dioxide develops from the reaction of carbonate salts with acid. The evolving gas permeated
through the alginate matrix, leaving gas bubbles or pores, which provided the beads buoyancy. The prepared beads were evaluated
for percent drug loading, drug entrapment efficiency, image, surface topography, buoyancy, and in vitro release. The formulations
were optimized for different weight ratios of gas-forming agent and sodium alginate. The beads containing higher amounts of
calcium carbonate demonstrated instantaneous, complete, and excellent floating ability over a period of 24 hours. The optimized
formulation was subjected to in vivo antitumor studies to check the therapeutic efficacy of the floating dosage forms containing
5-FU against benzo(a)pyrene-induced stomach tumors in albino female mice (Balb/C strain). The multiple-bead FDF was found
to reduce the tumor incidence in mice by 74%, while the conventional tablet dosage form reduced this incidence by only 25%.
Results indicate that FDF performed significantly better than the simple tablet dosage form.
Published: June 22, 2007 相似文献