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排序方式: 共有401条查询结果,搜索用时 31 毫秒
1.
Nelson Duran Jaime Rodriguez Andre Ferraz Victoriano Campos 《Biotechnology letters》1987,9(5):357-360
Summary
C. sitophila strain TFB-27441 showed 2–3 times higher lignolytic activity thanPhanerochaete chrysosporium (BKM-F-1767 strain). Lignin had a marked effect on the ligninase activity indicating that some induction or activation mechanism is involved in lignin degradation byC. sitophila. 相似文献
2.
Gyrodactylus gemini n. sp. (Monogenea, Gyrodactylidae) is described from the surface of the body and fins of the fish Semaprochilodus taeniurus (Steindachner) imported into Britain from the Venezuelan Amazon. The new species differs from other species of the genus,
including those described from South and Central America, by having: (i) stout hamuli with straight shafts and diverging roots;
(ii) marginal hooks with the sickle length larger than the width; (iii) a dorsal bar without a medial constriction; (iv) a
rectangular ventral bar with short processes; (v) a triangular ventral bar membrane; and, most obviously, (vi) at least two
generations which can develop two embryos simultaneously. This is the first known species of the genus Gyrodactylus from the Venezuelan Amazon and the first record of the subgenus Gyrodactylus (Gyrodactylus) from South America. 相似文献
3.
4.
E Caron C Ferraz F Heitz J Sr Widada J P Liautard 《Protein expression and purification》1991,2(2-3):188-193
We deleted exon 2 in human skeletal beta-tropomyosin (h beta-SK tropomyosin) using an improved adaptation of polymerase chain reaction (PCR) technology. The first PCR product was used to prime the full-length cDNA, leading to an exon 2-deleted h beta-SK tropomyosin. This new protein, des-(39-80)-tropomyosin, could then be expressed in Escherichia coli and purified to homogeneity. At the nucleotide level, the junction between exons 1 and 3 has been precisely made in the PCR product. The mutated protein was purified using high-performance liquid chromatography. Des-(39-80)-tropomyosin revealed new immunological properties but was still recognized by certain antitropomyosin antibodies. Furthermore, the structural characteristics of the mutated tropomyosin fit those of the full-length tropomyosin. This new adaptation of PCR technology appears to be suitable for every kind of mutation inside a cloned DNA molecule, and one mutation primer per mutation is sufficient. 相似文献
5.
The primary structure of the two less acidic parvalbumins (pI = 5.44 and pI = 4.95) from coelacanth muscle (Latimeria chalumnae) has been determined. They differ only by the presence or absence of a N-terminal blocking group. By the use of the automatic degradation, 69 amino acids could be placed unambiguously in the N-terminal part and 24 amino acids following the single arginine 75. Tryptic peptides were used to establish the sequence and the position of the remaining residues. The two parvalbumins examined belong to the alpha-lineage, and the rate of their molecular evolution is comparable to that found in other vertebrates. 相似文献
6.
AIMS: Ceriporiopsis subvermispora produces endoglucanase and beta-glucosidase when cultivated on cellulose or wood, but biodegradation of cellulose during biopulping by C. subvermispora is low even after long periods. To resolve this discrepancy, we grew C. subvermispora on Pinus taeda wood chips and purified the major beta-glucosidases it produced. Kinetic parameters were determined to clear if this fungus produces enzymes capable of yielding assimilable glucose from wood. METHODS AND RESULTS: Ceriporiopsis subvermispora was grown on P. taeda wood chips under solid-state fermentation. After 30 days, the crude extract obtained from enzyme extraction with sodium acetate buffer 50 mmol l(-1), pH 5.4, was filtrated in membranes with a molecular mass exclusion limit of 100 kDa. Enzyme purification was carried out using successively Sephacryl S-300 gel filtration. The retained fraction attained 76% of beta-glucosidase activity with 3.7-fold purification. Two beta-glucosidases were detected with molecular mass of 110 and 53 kDa. We have performed a characterization of the enzymatic properties of the beta-glucosidase of 110 kDa. The optimum pH and temperature were 3.5 and 60 degrees C, respectively. The K(m) and V(max) values were respectively 3.29 mmol l(-1) and 0.113 micromol min(-1) for the hydrolysis of p-nitrophenyl-beta-glucopyranoside (pNPG) and 2.63 mmol l(-1) and 0.103 micromol min(-1), towards cellobiose. beta-Glucosidase activity was strongly increased by Mn(2+) and Fe(3+), while Cu(2+) severely inhibited it. CONCLUSIONS: Ceriporiopsis subvermispora produces small amounts of beta-glucosidase when grown on wood. The gel filtration and polyacrylamide gel electrophoresis data revealed the existence of two beta-glucosidases with 110 and 53 kDa. The 110 kDa beta-glucosidase from C. subvermispora can be efficiently purified in a single step by gel filtration chromatography. The enzyme has an acid pH optimum with similar activity on pNPG and cellobiose and is thus typical beta-glucosidase. SIGNIFICANCE AND IMPACT OF THE STUDY: Ceriporiopsis subvermispora produces beta-glucosidase with limited action during wood decay making able its use for the production of biomechanical and biochemical pulps. The results presented in this paper show the importance of studying the behaviour of beta-glucosidases during biopulping. 相似文献
7.
Background
Influenza pandemic remains a serious threat to human health. Viruses of avian origin, H5N1, H7N7 and H9N2, have repeatedly crossed the species barrier to infect humans. Recently, a novel strain originated from swine has evolved to a pandemic. This study aims at improving our understanding on the pathogenic mechanism of influenza viruses, in particular the role of non-structural (NS1) protein in inducing pro-inflammatory and apoptotic responses.Methods
Human lung epithelial cells (NCI-H292) was used as an in-vitro model to study cytokine/chemokine production and apoptosis induced by transfection of NS1 mRNA encoded by seven infleunza subtypes (seasonal and pandemic H1, H2, H3, H5, H7, and H9), respectively.Results
The results showed that CXCL-10/IP10 was most prominently induced (> 1000 folds) and IL-6 was slightly induced (< 10 folds) by all subtypes. A subtype-dependent pattern was observed for CCL-2/MCP-1, CCL3/MIP-1α, CCL-5/RANTES and CXCL-9/MIG; where induction by H5N1 was much higher than all other subtypes examined. All subtypes induced a similar temporal profile of apoptosis following transfection. The level of apoptosis induced by H5N1 was remarkably higher than all others. The cytokine/chemokine and apoptosis inducing ability of the 2009 pandemic H1N1 was similar to previous seasonal strains.Conclusions
In conclusion, the NS1 protein encoded by H5N1 carries a remarkably different property as compared to other avian and human subtypes, and is one of the keys to its high pathogenicity. NCI-H292 cells system proves to be a good in-vitro model to delineate the property of NS1 proteins.8.
Cintia Camila Silva Angelieri Christine Adams-Hosking Katia Maria Paschoaletto Micchi de Barros Ferraz Marcelo Pereira de Souza Clive Alexander McAlpine 《PloS one》2016,11(1)
A mosaic of intact native and human-modified vegetation use can provide important habitat for top predators such as the puma (Puma concolor), avoiding negative effects on other species and ecological processes due to cascade trophic interactions. This study investigates the effects of restoration scenarios on the puma’s habitat suitability in the most developed Brazilian region (São Paulo State). Species Distribution Models incorporating restoration scenarios were developed using the species’ occurrence information to (1) map habitat suitability of pumas in São Paulo State, Southeast, Brazil; (2) test the relative contribution of environmental variables ecologically relevant to the species habitat suitability and (3) project the predicted habitat suitability to future native vegetation restoration scenarios. The Maximum Entropy algorithm was used (Test AUC of 0.84 ± 0.0228) based on seven environmental non-correlated variables and non-autocorrelated presence-only records (n = 342). The percentage of native vegetation (positive influence), elevation (positive influence) and density of roads (negative influence) were considered the most important environmental variables to the model. Model projections to restoration scenarios reflected the high positive relationship between pumas and native vegetation. These projections identified new high suitability areas for pumas (probability of presence >0.5) in highly deforested regions. High suitability areas were increased from 5.3% to 8.5% of the total State extension when the landscapes were restored for ≥ the minimum native vegetation cover rule (20%) established by the Brazilian Forest Code in private lands. This study highlights the importance of a landscape planning approach to improve the conservation outlook for pumas and other species, including not only the establishment and management of protected areas, but also the habitat restoration on private lands. Importantly, the results may inform environmental policies and land use planning in São Paulo State, Brazil. 相似文献
9.
Patrícia Ferraz de Matos 《The journal of the Royal Anthropological Institute》2020,26(1):211-212
10.