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1.
Abstract The purification of the cellulase from Odontotermes formosanus workers was achieved by using anion-exchange column of UNOsphere Q, BioLogic DuoFlow chromatography system. The purified cellulase was identified as an endoglucanase and some of its properties were investigated. The EGase activity was 807.5-fold as high as the initial enzyme activity using CMC as substrate and 14.4-fold using salicin as substrate. The enzyme preparations were homogeneous as judged by SDS-PAGE electrophoresis, molecular weight of which was 80 kDa and confirmed by 2-DE zymogram analysis. The enzyme was isoelectric at pH 6.4, which was active on CMC substrate. 相似文献
2.
Effect of Nucleotides and Other Inhibitors on the Inactivation of Glutamate Decarboxylase 总被引:5,自引:4,他引:1
Abstract: The effects of 17 nucleotides and nucleotide analogs and 11 other compounds on the glutamate-promoted inactivation of brain glutamate decarboxylase were examined. Among the nucleotides, the major determinant of potency was the polyphosphate chain, Glutamate-promoted inactivation was strongly enhanced by low concentrations (<100 μM) of adenosine tetraphosphate and all eight nucleoside triphosphates tested. Nucleoside diphosphates enhanced inactivation, but were much less effective than the nucleoside triphosphates; nucleoside monophosphates were not effective. Modification of the polyphosphate chain of the nucleoside triphosphates also affected potency; adenylylimidodiphosphate and α,β-methylene ATP were about as effective as nucleoside diphosphates, but α,β-methylene ATP was nearly as effective as ATP. The nucleoside base had only a small effect on potency; purine nucleotides were more potent than pyrimidine nucleotides, and one nucleotide with a tricyclic base, 1, N6 -etheno ATP, was as effective as the purine nucleoside triphosphates. The 2'-hydroxyl group of ribose was unimportant, since deoxy ATP was as effective as ATP. Three nonnucleotide polyanions were strong promoters of inactivation; inositol hexasulfate and 5-phosphorylribose 1-pyrophosphate were at least as effective as ATP; inositol hexaphosphate (phytate) was as effective as the nucleoside diphosphates. These results suggest that a major determinant of potency was a strong negative charge on the molecule. Negative charge was not sufficient, however, since fructose 1,6-bisphosphate did not promote inactivation. Inactivation by all of these compounds was slow, requiring more than 20 min for full effect. Two competitive inhibitors, chloride and glutarate, acted immediately and also reduced rather than enhanced glutamate-promoted inactivation. 相似文献
3.
利用DuoFlow层析系统阴离子交换柱UNOsphere Q,从黑翅土白蚁工蚁体内分离出内切葡聚糖酶。以羧甲基纤维素和水杨苷为底物,测得纯化酶的活性分别是原酶液的807.5和14.4倍。经变性聚丙烯酰胺凝胶电泳分析,获得单一的蛋白条带,其分子量大小为80kDa。经双向电泳图谱分析,其等电点为6.4。 相似文献
4.
Two phosphate rocks (PR), moderately reactive Hila PR from Colombia and slightly reactive Capinota PR from Bolivia, were compacted
with triple superphosphate (TSP) such that 50% of total P in the mixture was in water-soluble form. The effectiveness of these
materials as phosphorus sources was compared with that of partially acidulated phosphate rocks (PAPR) at 50% acidulation with
sulfuric acid and TSP in Hartsells silt loam (pH 4.5) with maize as the test crop. Huila PAPR and Huila PR compacted with
TSP were as effective as TSP as phosphorus sources. Huila PR was only half as effective. The slightly reactive Capinota PR
with 8.8% Al2O3 + Fe2O3 content was not suited for direct application, and Capinota PAPR was only half as effective as TSP. Capinota PR compacted
with TSP, however, was as effective as TSP. PR compacted with TSP, urea, and KCl was no more effective as phosphorus source
than PR compacted with TSP alone. 相似文献
5.
The ability of L-sorbose to stimulate cellulase production In shake flask culture of Trichoderma reesei was examined in mineral salts media (initial pH 5.0) containing either 1.0% D-xylose, 1.0% cellulose, and/or 0.1, 0.3, or 0.5% L-sorbose. When sorbose was the only carbon source, growth was limited, little substrate was utilized, pH increased, and cellulase activity was not apparent. The other carbon sources promoted good growth, pH dropped sharply to 2.5-3.0, substrate was utilized rapidly, and cellulase activity was detected. After three weeks of fermentation, twice as much cellulase activity was detected in the medium containing only cellulose as the carbon source, as compared to xylose as the carbon source. Cellulase activity was higher when media contained xylose supplemented with sorbose compared to xylose as the only carbon source. At 0.3 and 0.5% levels of sorbose supplementation of xylose-based media, cellulase activity was similar to that in cellulose-based media. 相似文献
6.
Veličković D Dimitrijević A Bihelović F Bezbradica D Knežević-Jugović Z Milosavić N 《Bioprocess and biosystems engineering》2012,35(7):1107-1115
Novel glucoside of physiological active vanillyl alcohol was synthesized for the first time using maltase from Saccharomyces cerevisiae as catalyst, and established its structure as 4-hydroxy-3-methoxybenzyl-α-D: -glucopyranoside. The key reaction factors for this transglucosylation reaction were optimized using response surface methodology and the highest yield so far in maltase catalyzed transglucosylation reaction was obtained. It was found out that optimum temperature of reaction was 37 °C, optimal maltose concentration was 60% (w/v), optimal pH was 6.6, and optimal concentration of vanillyl alcohol was 158 mM. Under these conditions, yield of glucoside was 90 mM with no by product formation. It was shown that this compound posses good antioxidant activity as well as stability in gastrointestinal tract. It was demonstrated that it is hydrolyzed on brush border membrane of enterocytes, so it can serve in protecting gastrointestinal system from oxidation, as well as source of anticonvulsive drug after the hydrolysis of glucoside on brush border membrane of small intestine. 相似文献
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The transport of mucus gel simulant (MGS) in a constricted simulated cough machine, using blood plasma as a serous layer simulant (SLS), was investigated. MGS was prepared from locust bean gum solutions crosslinked with varying amounts of added borate to produce gels of varying spinnability (filance). The model trachea was a plexiglass channel of rectangular cross-section with the plane bottom surface. The upper surface included a sinusoidal protrusion which provided a flow convergence with minimum gaps of 6, 4 and 2 mm. Experiments for mucus transport were conducted for these minimum gaps, as well as for the non-convergent case (12 mm gap). Miniaturization of sample quantity was achieved by keeping the MGS layer depth constant (0.5 or 1 mm) but reducing the zone of loading from 13.4 cm to 1 cm, thus reducing the sample requirement to as little as 0.2 ml. MGS transport was determined as the minimum displacement of a line of marker dye placed in the MGS layer at the point of minimum constriction gap. It was shown that in all cases (dry as well as with SLS), MGS transport increased as the minimum constriction gap between the plane and the convergent top surface decreased. This increase was further enhanced if an SLS of lesser viscosity was used. It was also found that the transport of MGS increased as the depth of MGS layer increased or as the filance decreased in both non-constricted and constricted cases. The relationship between MGS transport and filance was maintained even in the presence of an SLS layer. 相似文献
11.
Initial hydrogenation during catabolism of picric acid by Rhodococcus erythropolis HL 24-2. 总被引:7,自引:4,他引:3
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Rhodococcus erythropolis HL 24-2, which was originally isolated as a 2,4-dinitrophenol-degrading bacterium, could also utilize picric acid as a nitrogen source after spontaneous mutation. During growth, the mutant HL PM-1 transiently accumulated an orange-red metabolite, which was identified as a hydride-Meisenheimer complex of picric acid. This complex was formed as the initial metabolite and further converted with concomitant liberation of nitrite. 2,4,6-Trinitrocyclohexanone was identified as a dead-end metabolite of the degradation of picric acid, indicating the addition of two hydride ions to picric acid. 相似文献
12.
T Kohno D Kohda M Haruki S Yokoyama T Miyazawa 《The Journal of biological chemistry》1990,265(12):6931-6935
Nonprotein amino acid furanomycin was found to bind with Escherichia coli isoleucyl-tRNA synthetase (IleRS) almost as tightly as the substrate L-isoleucine. The conformation of furanomycin bound to the enzyme was determined by NMR analyses including the transferred nuclear Overhauser effect method. The conformation of IleRS-bound furanomycin was similar to that of L-isoleucine, although the chemical structure of furanomycin is unlike that of L-isoleucine. By E. coli IleRS, E. coli tRNAIle was charged with furanomycin as efficiently as with L-isoleucine. Furthermore, furanomycyl-tRNAIle was bound to polypeptide chain elongation factor Tu as tightly as isoleucyl-tRNAIle. Furanomycin was found to be incorporated into beta-lactamase precursor by in vitro protein biosynthesis. A newly designed amino acid will probably be incorporated into proteins, provided that the new amino acid takes a similar conformation as a protein-constituting amino acid in the active site of an aminoacyl-tRNA synthetase. 相似文献
13.
The host specificity of the gram-negative exoparasitic predatory bacterium Micavibrio aeruginosavorus was examined. M. aeruginosavorus preyed on Pseudomonas aeruginosa, as previously reported, as well as Burkholderia cepacia, Klebsiella pneumoniae, and numerous clinical isolates of these species. In a static assay, a reduction in biofilm biomass was observed as early as 3 hours after exposure to M. aeruginosavorus, and an approximately 100-fold reduction in biofilm cell viability was detected following a 24-h exposure to the predator. We observed that an initial titer of Micavibrio as low as 10 PFU/well or a time of exposure to the predator as short as 30 min was sufficient to reduce a P. aeruginosa biofilm. The ability of Micavibrio to reduce an existing biofilm was confirmed by scanning electron microscopy. In static and flow cell experiments, M. aeruginosavorus was able to modify the overall P. aeruginosa biofilm structure and markedly decreased the viability of P. aeruginosa. The altered biofilm structure was likely caused by an increase in cell-cell interactions brought about by the presence of the predator or active predation. We also conducted a screen to identify genes important for P. aeruginosa-Micavibrio interaction, but no candidates were isolated among the approximately 10,000 mutants tested. 相似文献
14.
Simmons MP Clevinger CC Savolainen V Archer RH Mathews S Doyle JJ 《American journal of botany》2001,88(2):313-325
Phylogenetic relationships within Celastraceae were inferred using a simultaneous analysis of 61 morphological characters and 1123 base pairs of phytochrome B exon 1 from the nuclear genome. No gaps were inferred, and the gene tree topology suggests that the primers were specific to a single locus that did not duplicate among the lineages sampled. This region of phytochrome B was most useful for examining relationships among closely related genera. Fifty-one species from 38 genera of Celastraceae were sampled. The Celastraceae sensu lato (including Hippocrateaceae) were resolved as a monophyletic group. Loesener's subfamilies and tribes of Celastraceae were not supported. The Hippocrateaceae were resolved as a monophyletic group nested within a paraphyletic Celastraceae sensu stricto. Goupia was resolved as more closely related to Euphorbiaceae, Corynocarpaceae, and Linaceae than to Celastraceae. Plagiopteron (Flacourtiaceae) was resolved as the sister group of Hippocrateoideae. Brexia (Brexiaceae) was resolved as closely related to Elaeodendron and Pleurostylia. Canotia was resolved as the sister group of Acanthothamnus within Celastraceae. Perrottetia and Mortonia were resolved as the sister group of the rest of the Celastraceae. Siphonodon was resolved as a derived member of Celastraceae. Maytenus was resolved as three disparate groups, suggesting that this large genus needs to be recircumscribed. 相似文献
15.
Denitrification by Thiobacillus denitrificans "RT" strain was investigated using manometry and gas chromatography. 1. From nitrate, resting cells produced only nitrogen anaerobically with thiosulfate as the electron donor. The data suggest that nitrate was assimilated and dissimilated by the same nitrate reductase, assayed with benzyl-viologen as the electron donor. 2. From nitrite, whole cells produced nitric oxide, nitrous oxide and nitrogen, using thiosulfate as the electron donor; nitrogen was the final product of the reduction. Crude extract reduced nitrite to nitrogen with p-phenylene-diamine and dimethyl-p-phenylene diamine as the electron donors, and produced nitric oxide, nitrous oxide and nitrogen with tetramethyl-p-phenylene-diamine as the electron donor. Nitrite was reduced to nitric oxide and nitrous oxide by crude extract using ascorbate-phenazine methosulfate as the electron donor. 3. From nitric oxide, whole cells produced nitrous oxide and nitrogen using thiosulfate as the electron donor, nitrogen was the final reduction product. Nitric oxide was reduced to nitrous oxide by crude extract with the ascorbate-phenazine methosulfate system. 4. Whole cells reduced nitrous oxide to nitrogen with thiosulfate as the electron donor. It was not possible to detect any nitrous oxide reductase activity in crude extract. 5. A scheme was of denitrification by Thiobacillus denitrificans "RT" strain. 相似文献
16.
The effects of 19-hydroxyprostaglandins (19-OH-PGs) were tested in vivo on the rabbit oviduct and uterus and on the rhesus monkey (Macaca mulatta) uterus. The 19-OH-PGEs suppressed spontaneous oviductal and uterine activity in the rabbit. The qualitative effect on the rabbit oviduct of 19-OH-PGEs was similar to that of PGE2. However, the typical response of the rabbit uterus to PGE2 was an increase in muscle activity. With regard to the rabbit oviduct, 19(R)-OH-PGE2 was as potent as PGE2, but 19(S)-OH-PGE2 was approximately 1/2 as potent as PGE2. Based on the dose of 19-OH-PGEs usually required to cause a minimal suppression and the dose of PGE2 required to cause a minimal stimulation of rabbit uterine activity, 19(R)-OH-PGE2 was twice as potent as PGE2 while 19(S)-OH-PGE2 was 1/2 as potent as PGE2. Stimulatory effects on the rabbit oviduct and uterus were observed following administration of 19-OH-PGFs and PGF2alpha. The potency on the rabbit oviduct of 19(S)-OH-PGF2alpha was about 1/5 to 1/10 that of PGF2alpha; the potency of 19(R)-OH-PGF2alpha was about 1/10 to 1/20 that of PGF2alpha. Both 19-OH-PGFs were approximately 1/5 to 1/10 as potent as PGF2alpha on the rabbit uterus. At the doses tested 19-OH-PGFs were inactive on the monkey uterus. Thus, these compounds are at least 1/5 as active as PGF2alpha. In contrast, 19(R)-OH-PGE2 had approximately the same potency as PGE2 in stimulating monkey uterine activity; but 19(S)-OH-PGE2 was approximately 1/3 as potent as PGE2. 相似文献
17.
以羰基二咪唑为催化剂,生物素与6-氨基己酸甲酯反应生成生物素-6-氨基己酸甲酯,该化合物通过酸碱萃取与原料分离,皂化后生成生物素氨基己酸.生物素氨基己酸在吡啶存在下与三氟乙酸对硝基苯酯进行转酯反应即得生物素对硝基苯酯.最后经光谱、色谱及核酸杂交证实了长臂生物素对硝基苯酯的化学结构和生物学活性. 相似文献
18.
P.G. Rodhouse 《Journal of experimental marine biology and ecology》1979,37(3):205-212
There are six beds of oysters in the estuary of the Beaulieu River, Hampshire; these correspond to areas of gravel bottom. Between November, 1974 and November, 1975 the population was dominated by large individuals (>5 years) and there was no evidence of significant recruitment during the previous two to three years. During the year the population filtered material with an energy content of 15.95 × 106 kcal; 30.4% of this is estimated to have been rejected as pseudofaeces; of the remainder, which was consumed, 30.7% was passed as faeces, 29.0% was respired and lost as heat, 6.4% was diverted into production of soft tissue and shell organics. and 5.5% was released as gonad output. The remaining 28.4% may be partly accounted for as excreta lost to the population as mucus and dissolved organic matter. Gonad output was proportionally large due to the presence of a high percentage of older individuals; this energy was lost from the population and there was no recruitment. 相似文献
19.
Initial hydrogenation during catabolism of picric acid by Rhodococcus erythropolis HL 24-2. 总被引:4,自引:0,他引:4
Rhodococcus erythropolis HL 24-2, which was originally isolated as a 2,4-dinitrophenol-degrading bacterium, could also utilize picric acid as a nitrogen source after spontaneous mutation. During growth, the mutant HL PM-1 transiently accumulated an orange-red metabolite, which was identified as a hydride-Meisenheimer complex of picric acid. This complex was formed as the initial metabolite and further converted with concomitant liberation of nitrite. 2,4,6-Trinitrocyclohexanone was identified as a dead-end metabolite of the degradation of picric acid, indicating the addition of two hydride ions to picric acid. 相似文献
20.
The role of the ceramide moiety of gangliosides, together with the deriving aggregative properties of ganglioside in solution, in the process of ganglioside-cell interactions was studied. The natural GM1(stearoyl) and the synthetic GM1(acetyl), containing the stearoyl and acetyl groups as the acyl moiety, respectively, were used in binding experiments to rat cerebellar granule cells. Regardless of the cell culture conditions, such as the presence of absence of fetal calf serum, the association of GM1(acetyl) to the cells was much greater than that of GM1(stearoyl). GM1(acetyl) was present in the incubation medium as monomers. After incubation, a large part of the total GM1(acetyl) associated to cells, 76-93% depending on the experimental conditions, was removed by washing with protein solutions. The remaining associated ganglioside was not removed by repeating washing with protein solutions or trypsin treatments and was considered as a component of the membrane. The cell association of GM1(stearoyl), present in solution as monomers as well as micelles, could be classified as serum-labile, trypsin-labile and trypsin-stable. The trypsin-stable form of association, corresponding to the molecules stably inserted into the membrane, was proportionally higher, the proportions varying with increasing incubation time and decreasing ganglioside concentration. This form of association was particularly high when incubation was performed in the presence of fetal calf serum. Incubation experiments performed with a mixture of GM1(stearoyl) and GM1(acetyl) in a molar ratio which allowed their presence in the medium as monomers as well as mixed micelles, led to a ganglioside association suggesting that besides the aggregative properties of the molecule other ganglioside properties are involved in the ganglioside-cell interaction process. 相似文献