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1.
Cryptosporidium parvum is the second leading cause of persistent diarrhea among children in low-resource settings. This study examined the effect of oregano essential oil (OEO) and carvacrol (CV) on inhibition of C. parvum infectivity in vitro. HCT-8 cells were seeded (1 × 106) in 96-well microtiter plates until confluency. Cell viability and infectivity were assessed by seeding HCT-8 cell monolayers with C. parvum oocysts (1 × 104) in two modalities: 1) 4 h co-culture with bioactive (0–250 μg/mL) followed by washing and incubation (48 h, 37 °C, 5% CO2) in bioactive-free media; and 2) 4 h co-culture of C. parvum oocysts followed by washing and treatment with bioactive (0–250 μg/mL) during 48-h incubation. Cell viability was tested using Live/Dead? assay whereas infectivity was measured using C. parvum-specific antibody staining via immunofluorescence detection. Loss of cell viability was observed starting at 125 μg/mL and 60 μg/mL for OEO and CV, respectively. Neither OEO nor CV modulated the invasion of C. parvum sporozoites in HCT-8 cells. Treatment with bioactive after invasion reduced relative C. parvum infectivity in a dose-dependent manner to 55.6 ± 10.4% and 45.8 ± 4.1% at 60 and 30 μg/mL of OEO and CV, respectively. OEO and CV are potential bioactives to counteract C. parvum infection in children.  相似文献   

2.
Taxonomic assignments of anaerobic dichloromethane (DCM)-degrading bacteria remain poorly constrained but are important for understanding the microbial diversity of organisms contributing to DCM turnover in environmental systems. We describe the taxonomic classification of a novel DCM degrader in consortium RM obtained from pristine Rio Mameyes sediment. Phylogenetic analysis of full-length 16S rRNA gene sequences demonstrated that the DCM degrader was most closely related to members of the genera Dehalobacter and Syntrophobotulus, but sequence similarities did not exceed 94% and 93%, respectively. Genome-aggregate average amino acid identities against Peptococcaceae members did not exceed 66%, suggesting that the DCM degrader does not affiliate with any described genus. Phylogenetic analysis of conserved single-copy functional genes supported that the DCM degrader represents a novel clade. Growth strictly depended on the presence of DCM, which was consumed at a rate of 160 ± 3 μmol L?1 d?1. The DCM degrader attained 5.25 × 107 ± 1.0 × 107 cells per μmol DCM consumed. Fluorescence in situ hybridization revealed rod-shaped cells 4 ± 0.8 μm long and 0.4 ± 0.1 μm wide. Based on the unique phylogenetic, genomic, and physiological characteristics, we propose that the DCM degrader represents a new genus and species, ‘Candidatus Dichloromethanomonas elyunquensis’.  相似文献   

3.
This study aimed to evaluate the effect of commercially used entomopathogens on Africanized Apis mellifera L. (Hymenoptera: Apidae). Four bioassays were performed: 1) pulverized entomopathogens on A. mellifera; 2) entomopathogens sprayed on a smooth surface; 3) entomopathogens sprayed on soy leaves; and 4) entomopathogens mixed with candy paste (sugar syrup). Five treatments were prepared: sterile distilled water (control), distilled water sterilized with Tween® 80 (0.01%), and the commercial entomopathogens Metarhizium anisopliae E9 (1.0 × 109 conidia mL?1), Beauveria bassiana PL63 (1.0 × 108 conidia mL?1) and Bacillus thuringiensis var. kurstaki HD-1 (3.0 × 108 spores mL?1). Each treatment consisted of five repetitions, with 20 workers per repetition, which were stored in a plastic box and, later, in a biological oxygen demand (B.O.D.) incubator (27 ± 2 °C, RH of 60% ± 10%, 12-h photophase). The mortality of the workers was evaluated from 1 h to 240 h, and the data were analyzed using Bayesian inference. The workers killed by the ingestion of candy paste contaminated with the pathogens (products) were randomly separated and selected for the removal of the midgut. Each midgut was fixed in Bouin's solution and prepared for histology. B. bassiana was verified to reduce the survival of A. mellifera workers in all bioassays. Moreover, M. anisopliae reduced the survival of A. mellifera workers directly sprayed, on a smooth surface and mixed with candy. B. thuringiensis reduced A. mellifera survival on a smooth surface and mixed with candy paste. However, its effects were lower than that observed by B. bassiana. The treatments with the biological products did not induce morphometric alterations in the midgut of A. mellifera.  相似文献   

4.
In this paper, we describe a method for primary culture of a well differentiated electrically tight rabbit vocal fold epithelial cell multilayer and the measurement of transepithelial electrical resistance (TEER) for the evaluation of epithelial barrier function in vitro. Rabbit larynges were harvested and enzymatically treated to isolate vocal fold epithelial cells and to establish primary culture. Vocal fold epithelial cells were co-cultured with mitomycin C-treated feeder cells on collagen-coated plates. After 10–14 days in primary culture, cells were passaged and cultured until they achieved 70–90% confluence on collagen-coated plates. Epithelial cells were then passaged onto collagen-coated cell culture inserts using 4.5 cm2 membrane filters (1.0 μm pore size) with 10% fetal bovine serum or 30 μg/mL bovine pituitary extract to investigate the effects of growth-promoting additives on TEER. Additional experiments were performed to investigate optimal seeding density (1.1, 2.2, 4.4, or 8.9 × 105 cells/cm2), the effect of co-culture with feeder cells, and the effect of passage number on epithelial barrier function. Characterization of in vitro cultures was performed using hematoxylin and eosin staining and immunostaining for vocal fold epithelial cell markers and tight junctions. Results revealed higher TEER in cells supplemented with fetal bovine serum compared to bovine pituitary extract. TEER was highest in cells passaged at a seeding density of 2.2 × 104 cells/cm2, and TEER was higher in cells at passage two than passage three. Ultrastructural experiments revealed a well-differentiated epithelial cell multilayer, expressing the epithelial cell markers CK13, CK14 and the tight junction proteins occludin and ZO-1.  相似文献   

5.
A cDNA encoding farnesyl pyrophosphate synthase of Babesia bovis (BbFPPS) has been isolated, cloned and characterized as molecular drug target. Sequence analysis revealed that BbFPPS contains an open reading frame of 1011 bp with predicted 336 amino acids and molecular mass of 38 kDa. Antiserum raised in mice against recombinant BbFPPS expressed in Escherichia coli specifically reacted with native protein of B. bovis parasites by Western blot analysis and indirect immunofluorescent test. Enzymatic assay using recombinant BbFPPS revealed that the Km value of the enzyme for isopentenyl pyrophosphate and dimethylallyl pyrophosphate was 2.494 ± 1.536 μM. Risedronate inhibited the activity of BbFPPS yielding IC50 value of 8.4 ± 1.2 nM. Furthermore, the in vitro growth of B. bovis was significantly inhibited in the presence of a micromolar concentration of risedronate (IC50 = 4.02 ± 0.91 μM). No regrowth of B. bovis was observed at 10 μM of risedronate in the subsequent viability test. These results demonstrate that BbFPPS is the molecular target of risedronate, which could inhibit the in vitro growth of B. bovis.  相似文献   

6.
A series of new 1H-benzo[d]imidazole derivatives of dehydroabietic acid were designed and synthesized as potent antitumor agents. Structures of the target molecules were characterized using MS, IR, 1H NMR, 13C NMR and elemental analyses. In the in vitro cytotoxic assay, most compounds showed significant cytotoxic activities against two hepatocarcinoma cells (SMMC-7721 and HepG2) and reduced cytotoxicity against noncancerous human hepatocyte (LO2). Among them, compound 7b exhibited the best cytotoxicity against SMMC-7721 cells (IC50: 0.36 ± 0.13 μM), while 7e was most potent to HepG2 cells (IC50: 0.12 ± 0.03 μM). The cell cycle analysis indicated that compound 7b caused cell cycle arrest of SMMC-7721 cells at G2/M phase. Further, compound 7b also induced the apoptosis of SMMC-7721 cells in Annexin V-APC/7-AAD binding assay.  相似文献   

7.
A new γ-carbonic anhydrase (CA, EC 4.1.1.1) was cloned and characterized kinetically in the genome of the bacterial pathogen Burkholderia pseudomallei, the etiological agent of melioidosis, an endemic disease of tropical and sub-tropical regions of the world. The catalytic activity of this new enzyme, BpsCAγ, is significant with a kcat of 5.3 × 105 s?1 and kcat/Km of 2.5 × 107 M?1 × s?1 for the physiologic CO2 hydration reaction. The inhibition constant value for this enzyme for 39 sulfonamide inhibitors was obtained. Acetazolamide, benzolamide and metanilamide were the most effective (KIs of 149–653 nM) inhibitors of BpsCAγ activity, whereas other sulfonamides/sulfamates such as ethoxzolamide, topiramate, sulpiride, indisulam, sulthiame and saccharin were active in the micromolar range (KIs of 1.27–9.56 μM). As Burkholderia pseudomallei is resistant to many classical antibiotics, identifying compounds that interfere with crucial enzymes in the B. pseudomallei life cycle may lead to antibiotics with novel mechanisms of action.  相似文献   

8.
Two series of xanthotoxin-triazole derivatives were designed, synthesized, and studied for their antiproliferative properties. The in vitro cytotoxicity of the compounds in the AGS cancer cell line and the L02 normal cell line was evaluated via MTT assay. Among the synthesized compounds, 9-((1-(4-(trifluoromethyl)phenyl)-1H-1,2,3-triazol-4-yl)methoxy)-7H-furo[3,2-g]chromen-7-one (6p) was found to have the greatest antiproliferative activity against AGS cells (IC50 = 7.5 μM) and showed better activity than the lead compound (xanthotoxin, IC50 > 100 μM) and the reference drug (5-fluorouracil, IC50 = 29.6 μM) did. The IC50 value of 6p in L02 cells was 13.3 times higher than that in the AGS cells. Therefore, the compound exhibited better therapeutic activity and specificity compared with the positive control 5-fluorouracil. Cell cycle analysis revealed that compound 6p inhibited cell growth via the induction of S/G2 phase arrest in AGS cells. Compound 6p was identified as a promising lead compound for the further development and identification of 1,2,3-triazole-based anticancer agents.  相似文献   

9.
The aim of this study was to develop a loop-mediated isothermal amplification (LAMP) combined with a chromatographic lateral flow dipstick (LFD) assay to rapidly and specifically detect the Karlodinium veneficum ITS gene. Four groups of LAMP primers were specially designed to target the K. veneficum ITS gene. The LAMP-LFD detection limit was 7.4 pg/μL (approximately 6.5 cells/mL) of K. veneficum genomic DNA and was 10 times more sensitive than standard PCR. The LAMP-LFD method exhibited high specificity and accurately identified K. veneficum algal isolates, but not other algal isolates. To test the assay’s accuracy, samples from positive results were further analyzed by sequencing and phylogenetic analysis, all of which were identified as K. veneficum. Over all, the LAMP-LFD assay established in this paper can be used as a reliable and simple method to detect the K. veneficum.  相似文献   

10.
Enzymes in the newly described rumen bacterium, Treponema zioleckii strain kT, capable of digesting Timothy grass fructan, inulin, and sucrose were identified and characterized. Two specific endolevanases and one non-specific β-fructofuranosidase were found in a cell-free extract. The molecular weight of the endolevanases were estimated to be 60 and 36 kDa, whereas that of β-fructofuranosidase, 87 kDa. The former of the specific enzymes was associated with the outer membrane, while the latter and the non-specific β-fructofuranosidase, with the periplasm or cytosol. The Km and Vmax for Timothy grass fructan degradation by endolevanase were 0.27% and 15.75 μM fructose equivalents × mg protein?1 × min?1, those for sucrose and inulin digestion by β-fructofuranosidase were 1.35 × 10?3 M and 1.73 μM hexoses × mg protein?1 × min?1 and 1.77% and 1.83 μM hexoses × mg protein?1 × min?1, respectively.  相似文献   

11.
Thirty-six new α-benzylidene-γ-lactone compounds based α-methylene-γ-butyrolactone substructure were prepared and characterized by spectroscopic analysis. All compounds were evaluated for antifungal activities in vitro against six plant pathogenic fungi and the half maximal inhibitory concentration (IC50) against Botrytis cinerea and Colletotrichum lagenarium were investigated. Compounds 5c-3 and 5c-5 with the halogen atom exhibited excellent fungicidal activity against B. cinerea (IC50 = 22.91, 18.89 μM). The structure-activity relationships (SARs) analysis indicated that the derivatives with electron-withdrawing substituents at the meta- or para-positions improves the activity. Via the heuristic method, the generated quantitative structure-activity relationship (QSAR) model (R2 = 0.961) revealed a strong correlation of antifungal activity against B. cinerea with molecular structures of these compounds. Meanwhile, the cytotoxicity of 20 representative derivatives was tested in the human tumor cells line (HepG2) and the hepatic L02 cells line, the result indicated that the synthesized compounds showed significant inhibitory activity and limited selectivity. Compound 5c-5 has the highest fungicidal activity with IC50 = 18.89 μM (against B. cinerea.) but low cytotoxicity with IC50 = 35.4 μM (against HepG2 cell line) and IC50 = 68.8 μM (against Hepatic L02 cell line). These encouraging results can be providing an alternative, promising use of α-benzylidene-γ-lactone through the design and exploration of eco-friendly fungicides with low toxicity and high efficiency.  相似文献   

12.
《Small Ruminant Research》2009,85(1-3):89-99
We aimed to quantify the sources of variation contributing to the production and quality of cashmere produced in five districts in Osh and Naryn provinces of Kyrgyzstan. In early spring 2008 mid-side cashmere samples were taken from 719 cashmere adult females, and 41 cashmere adult males and castrates. Samples came from 53 villages and a total of 156 farmers’ flocks. For 91 goats from 33 farmers in 13 villages of two districts that had been sampled earlier, cashmere was combed from the goat at the time of a second visit (end of April 2008) when the cashmere would normally be harvested. Following standard cashmere objective measurement, data were examined using general linear modelling to quantify the effects of potential determinants. The mean fibre diameter (MFD) of cashmere differed between provinces (Osh 15.7 μm, Naryn 16.7 μm; P = 4.4 × 10−20). About 42% of the cashmere was <16 μm, 48% was 16.0–18.0 μm and 9.5% was >18.0 μm. Most of the cashmere samples were coloured (81%), with 63% black and 19% white. The percentage of cashmere samples that were white declined as MFD increased (26% < 14 μm to 11% of >18 μm). The primary determinants of cashmere MFD of individual goats were age of goat (range 1.46 μm, P = 1.8 × 10−12) and farm (range 6.5 μm, P = 1.7 × 10−14). The lesser effects detected for sex (range 0.9 μm, P = 0.026) and colour of cashmere (range 1.8 μm, P = 0.023) were based on small sample sizes and are unreliable. Age of goat had important affects on fibre diameter variation (up to 1.7% in coefficient of variation, P = 5.8 × 10−6) and fibre curvature (2.5–5°/mm, P = 2.1 × 10−4). By far the greatest effect on fibre curvature was cashmere MFD (P = 3.0 × 10−104) with a smaller effect of sex (about 5°/mm, P = 3.0 × 10−6). Village effects were detected on fibre diameter variability (range 4.5% in coefficient of variation, P = 0.027) and fibre curvature (range 15°/mm, P = 1.6 × 10−7). There was a strong negative association between increasing MFD and declining fibre curvature (−5.11 ± 0.181°/mm per 1 μm; P = 7.1 × 10−121; r2 = 0.51). Average combed cashmere weight was 164 g, the clean cashmere content was 0.661 and median clean cashmere production was 110 g per goat (range 60–351 g). Combed cashmere production increased with altitude of the village, probably related to different moulting times as spring temperatures warmed up later in higher altitude villages up to 3200 masl. Measurements of combed cashmere MFD were coarser than the mid-side samples taken earlier in the year. There are farmers and cashmere goats in the sampled districts of Kyrgyzstan which produce the finest qualities of commercial cashmere as the vast majority of cashmere is fine, has low variation in fibre diameter and has fibre crimping (curvature) typical of Chinese and Mongolian cashmere. There is substantial scope to increase the production and commercial value of cashmere produced by Kyrgyz goats. In particular, some villages and farmers need to change their buck selection practices if they wish to produce acceptable cashmere. Farmers should separate their finer and white cashmere prior to sale.  相似文献   

13.
Trichinella spiralis is a tissue-dwelling nematode parasite. A loop-mediated isothermal amplification (LAMP) assay was developed and validated for the sensitive and rapid detection of T. spiralis larvae in muscle samples. Sixteen sets of primers were designed to recognise distinct sequences of a conserved gene, a 1.6 kb repetitive element of the Trichinella genome. One set of primers was selected as the most appropriate for rapid detection. The specificity and sensitivity of the primers in LAMP reactions for T. spiralis larvae and muscle samples of mice infected with T. spiralis were determined. Another 10 heterologous parasites were selected for specificity assays. The results showed that target DNA was amplified and visualised by monitoring turbidity and adding calcein detection methods within 70 min at an isothermal temperature of 63 °C. The sensitivity of LAMP with the detection limit of 362 fg/μl was >10 times higher than that for PCR. The designed primers had a good specificity. No cross-reactivity was found with the DNA of any other parasites. The assay was able to detect T. spiralis in all mouse muscle samples infected with 10 T. spiralis larvae on day 20 p.i. We believe this is the first report regarding the application of the LAMP assay for detection of T. spiralis larvae in muscle samples from experimentally infected mice. This method demonstrates a potentially valuable means for the direct detection of T. spiralis larvae in meat inspection.  相似文献   

14.
Following up the SAR study of triazolothiadiazoles for their antitubercular activities targeting Mt SD in our previous study, on the principle of scaffold hopping, the C3 and C6 positions of triazolothiadiazine were examined systematically to define a preliminary structure–activity relationship (SAR) with respect to biological activity. This study herein highlights the potential of two highly potent advanced leads 6c-3, 6g-3 and several other compounds with comparable potencies as promising new candidates for the treatment of TB (6c-3, MIC-H37Rv = 0.25 μg/mL; MIC-MDRTB = 2.0 μg/mL; MIC-RDRTB = 0.25 μg/mL; Mt SD-IC50 = 86.39 μg/mL; and 6g-3, MIC-H37Rv = 1.0 μg/mL; MIC-MDRTB = 4.0 μg/mL; MIC-RDRTB = 2.0 μg/mL; Mt SD-IC50 = 73.57 μg/mL). Compounds 6c-3 and 6g-3 possessed a para-nitro phenyl at the 6 position showed low Vero and HepG2 cells toxicity, turning out to be two excellent lead candidates for preclinical trials. In addition, in vitro Mt SD inhibitory assay indicates that Mt SD is at least one of the targets for their antitubercular activity. Thus, they may turn out to be promising multidrug-resistance-reversing agents.  相似文献   

15.
To identify an effective ligand that binds to a G-quadruplex structure but not a double-stranded DNA (dsDNA), a set of biophysical and biochemical experiments were carried out using newly synthesized cyclic ferrocenylnaphthalene diimide (cFNDI, 1) or the non-cyclic derivative (2) with various structures of G-quadruplex DNAs and dsDNA. Compound 1 bound strongly to G-quadruplexes DNAs (106 M?1 order) with diminished binding to dsDNA (104 M?1 order) in 100 mM AcOH-AcOK buffer (pH 5.5) containing 100 mM KCl. Interestingly, 1 showed an approximately 50-fold higher selectivity to mixed hybrid-type telomeric G-quadruplex DNA (K = 3.4 × 106 M?1 and a 2:1 stoichiometry) than dsDNA (K = 7.5 × 104 M?1) did. Furthermore, 1 showed higher thermal stability to G-quadruplex DNAs than it did to dsDNA with a preference for c-kit and c-myc G-quadruplex DNAs over telomeric and thrombin binding aptamers. Additionally, 1 exhibited telomerase inhibitory activity with a half-maximal inhibitory concentration (IC50) of 0.4 μM. Compound 2 showed a preference for G-quadruplex; however, the binding affinity magnitude and preference were improved in 1 because the former had a cyclic structure.  相似文献   

16.
《Process Biochemistry》2010,45(3):323-334
Enrichment of anaerobic ammonium oxidation (anammox) bacteria using five activated sludges in three domestic wastewater treatment plants (WWTPs) were processed in a short term of 70 days and evaluated by real-time quantitative PCR (RTQ-PCR). Before the enrichment, building phylogenetic trees of Planctomycetes phylum in four reactors of sequencing batch reactor (SBR), anoxic and oxic reactors of anaerobic–anoxic–oxic (A2O) process, and rotating biological contactor (RBC) revealed six groups of distantly relative genera of Planctomyces, Pirellula, Gemmata, Isophaera, Candidatus and putative anammox bacteria. All clones of Candidatus sp. were affiliated with anammox bacteria and the majority of anammox clones were related to Planctomycete KSU-1 (AB057453). The discovery of anammox bacteria in raw activated sludges provided a partial rationale for the utilization of activated sludge as a seeding source of the anammox process. To verify the activity of anammox bacteria in the activated sludges, enrichment cultivations were conducted using SBRs. The enrichment of anammox bacteria resulted in the significant anammox activity of three samples. Quantification of 16S rRNA gene of anammox bacteria using RTQ-PCR showed the highest concentration of anammox bacteria of 2.48 ± 0.22 × 109 copies of 16S rRNA gene/mg-volatile suspended solids (VSS), which was the same order of magnitude as that of the referential granular anammox sludge, 6.23 ± 0.59 × 109 copies of 16S rRNA gene/mg-VSS, taken from an anammox upflow anaerobic sludge blanket (UASB) reactor. The doubling time of anammox bacteria enriched in this study was 1.18 days. The growth yield of anammox bacteria enriched in this study was 4.75 ± 0.57 × 106 copies of 16S rRNA gene/mg of ammonium- and nitrite-nitrogen, which was similar to 4.50 ± 0.61 × 106 copies of 16S rRNA gene/mg of ammonium- and nitrite-nitrogen for the referential anammox sludge. Substrate uptake rates of three successful enrichments at the end of the enrichment were comparable to those of granular and suspended anammox sludges. Rapid enrichment of anammox bacteria using activated sludge could offer an alternative method for obtaining a large volume of seeding anammox sludge.  相似文献   

17.
Desert truffles are seasonal and important edible fungi that grow wild in many countries around the world. Truffles are natural food sources that have significant compositions. In this work, the antioxidant, chemical composition, anticancer, and antiangiogenesis properties of the Terfezia claveryi truffle were investigated. Solvent extractions of the T. claveryi were evaluated for antioxidant activities using (DPPH, FRAP and ABTS methods). The extracts cytotoxicity on the cancer cell lines (HT29, MCF-7, PC3 and U-87 MG) was determined by MTT assay, while the anti-angiogenic efficacy was tested using ex-vivo assay. All extracts showed moderate anticancer activities against all cancer cells (p < 0.05). The hexane extract inhibited the brain cell line (U-87 MG) with an IC50 of 50 μg/ml and significantly promoted cell apoptosis through the mitochondrial pathway and DNA fragmentation p < 0.001. The ethanol extract demonstrated potent antioxidants; DPPH, FRAP, and ABTS with an IC50 value of 52, 48.5 and 64.7 μg/ml, respectively. In addition, the hexane and ethyl acetate extract significantly (p < 0.001) inhibited the sprouting of microvessels by 100% and 81.2%, at 100 μg/ml, respectively. The GC analysis of the most active extract (hexane) showed the presence of several potent phytochemicals such as stigmasterol, beta-Sitosterol, squalene, lupeol, octadecadienoic acid, and oleic acid.  相似文献   

18.
The biological activities of the ethanol extract from Cirsium japonicum var. maackii (ICF-1) and its major component, polyphenol cirsimaritin, were investigated as part of the search for possible alternative drugs for breast cancer. Three in vitro cell-based assays were used: the cell proliferation assay, tube-formation assay, and Western blot analysis. Both the ICF-1 extract and cirsimaritin inhibited the viability of HUVECs in a dose-dependent manner. The inhibition achieved was 36.89% at a level of 200 μg/ml by the ICF-1 extract and 62.04% at a level of 100 μM by cirsimaritin. The ICF-1 extract and cirsimaritin reduced tube formation by 12.69% at level of 25 μg/ml and 32.18% at the levels of 6.25 μM, respectively. Cirsimaritin inhibited angiogenesis by downregulation of VEGF, p-Akt and p-ERK in MDA-MB-231 cells, suggesting that cirsimaritin is potentially useful as an anti-metastatic agent. The present study demonstrated that Cirsium japonicum extract and its active component cirsimaritin is an excellent candidate as an alternative anti-breast cancer drug.  相似文献   

19.
Laccase enzyme (L) from Trametes versicolor was entrapped in three hydrogel structures namely poly(acrylamide-N-isopropylacrylamide), P(AAm-NIPA), and semi-interpenetrating networks of poly(acrylamide)/alginate, P(AAm)/Alg, and poly(acrylamide-N-isopropylacrylamide)/alginate, P(AAm-NIPA)/Alg. The optimum temperatures for free and all immobilized systems were found to be 40 °C. For free and immobilized laccase systems of P(AAm-NIPA)-L, P(AAm)/Alg-L and P(AAm-NIPA)/Alg-L, Km values were found to be 6.7 × 10?3, 8.8 × 10?2, 5.5 × 10?2 and 1.8 × 10?2 mM; Vmax values were calculated as 1.8 × 10?3, 2.5 × 10?2, 1.5 × 10?2 and 6.1 × 10?3 mM min?1, respectively. For free and the same immobilized systems, the enzymes retained 42%, 91%, 79% and 86% of their initial activities at the end of 56 days of storage. After using the mentioned immobilized systems repeatedly 10 times, they retained 77%, 71% and 84% of their original activities, respectively. For free and the same immobilized systems, decolorization of Acid Orange 52 (AO52) in 6 h were found to be 63%, 50%, 48% and 66%, respectively. Addition of 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid), ABTS, into the assay medium increased these values up to 73%, 73%, 74% and 75%, respectively.  相似文献   

20.
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