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991.
Wetlands Ecology and Management - The growth of human societies worldwide has been associated with the degradation of natural resources; in particular, freshwater ecosystems are among the most... 相似文献
992.
Letícia Maria Zanphorlin Mariana Abrahão Bueno de Morais José Alberto Diogo Mariane Noronha Domingues Flávio Henrique Moreira de Souza Roberto Ruller Mario Tyago Murakami 《Biotechnology and bioengineering》2019,116(4):734-744
Rational design is an important tool for sculpting functional and stability properties of proteins and its potential can be much magnified when combined with in vitro and natural evolutionary diversity. Herein, we report the structure-guided design of a xylose-releasing exo-β-1,4-xylanase from an inactive member of glycoside hydrolase family 43 (GH43). Structural analysis revealed a nonconserved substitution (Lys247) that results in the disruption of the hydrogen bond network that supports catalysis. The mutation of this residue to a conserved serine restored the catalytic activity and crystal structure elucidation of the mutant confirmed the recovery of the proper orientation of the catalytically relevant histidine. Interestingly, the tailored enzyme can cleave both xylooligosaccharides and xylan, releasing xylose as the main product, being the first xylose-releasing exo-β-1,4-xylanase reported in the GH43 family. This enzyme presents a unique active-site topology when compared with closely related β-xylosidases, which is the absence of a hydrophobic barrier at the positive-subsite region, allowing the accommodation of long substrates. Therefore, the combination of rational design for catalytic activation along with naturally occurring differences in the substrate binding interface led to the discovery of a novel activity within the GH43 family. In addition, these results demonstrate the importance of solvation of the β-propeller hollow for GH43 catalytic function and expand our mechanistic understanding about the diverse modes of action of GH43 members, a key and polyspecific carbohydrate-active enzyme family abundant in most plant cell-wall-degrading microorganisms. 相似文献
993.
Paloma Rocha Arakaki Paula Andrea Borges Salgado Joo Diego de Agostini Losano Marcel Henrique Blank Marcílio Nichi Ricardo Jos Garcia Pereira 《American journal of primatology》2019,81(8)
The golden‐headed lion tamarin (Leontopithecus chrysomelas) is an endangered species endemic to Brazil's Atlantic Forest, a shrinking biodiversity hotspot. As in other Neotropical primates, its semen characteristics and freezability are poorly studied. Hence, reproductive technologies for callitrichids would greatly benefit from reliable methods of semen analysis. In a bid to promote reproductive research in tamarins, we validated simple and inexpensive sperm function tests that can be used to monitor sperm‐egg binding, plasma membrane and acrosome integrity, mitochondrial activity, and DNA fragmentation. Ejaculates from adult males were individually diluted and divided into control and damage‐induced aliquots, and then samples comprising assorted amounts of damaged spermatozoa were examined by organelle‐specific tests. Our findings showed that sperm‐binding in chicken egg perivitelline membrane (EPM) positively correlated with the number of spermatozoa injured by snap‐freezing. Eosin‐nigrosin (EN) and propidium iodide readings were correlated with each other, and both provided robust measurements of plasma membrane integrity. A high correlation between expected and measured amounts of acrosome‐intact spermatozoa was found using Fast Green‐Rose Bengal (FG‐RB), Coomassie Blue (CB), and FITC‐PSA stains, and all three methods exhibited comparable results. Likewise, different percentages of UV‐irradiated spermatozoa were accurately assessed for DNA integrity by Toluidine Blue (TB) and sperm chromatin dispersion (SCD) tests. Comparisons between 3,3′‐diaminobenzidine (DAB) and JC‐1 stains also indicated the reliability of the former assay to ascertain gradual increases in spermatozoa with greater mitochondrial function. These data confirmed that different parts of the tamarin spermatozoa can be simply and consistently evaluated by EPM, EN, FG‐RB, CB, TB, and DAB protocols. 相似文献
994.
995.
Gustavo Arruda Viani Juliana Fernandes Pavoni Ligia Issa De Fendi 《Reports of Practical Oncology and Radiotherapy》2021,26(2):218
BackgroundThe aim of this study was to evaluate the effectiveness of prophylactic corticosteroids to prevent pain flare (PF) in bone metastases treated with radiotherapy performing a meta-analysis of randomized clinical trials (RCT).Materials and methodsRCTs were identified on Medline, Embase, the Cochrane Library, and the proceedings of annual meetings through June 2020. We followed the PRISMA and MOOSE guidelines. A meta-analysis was performed to assess if corticosteroids reduce the PF, pain progression, and the mean of days with PF compared with the placebo. A p-value < 0.05 was considered significant.ResultsThree RCTs with a total of 713 patients treated were included. The corticosteroids reduced the occurrence of early PF 20.5% (51/248) versus 32% (80/250) placebo, OR = 0.55 (95% CI: 0.36–0.82, p = 0.002). The mean days of PF were reduced to 1.6 days (95% CI: 1.3–1.9, p = 0.0001). Prophylactic corticosteroids had more patients with no PF and no pain progression, OR = 1.63 (95% CI: 1.14–2.32, p = 0.007). No significant corticosteroids effect was observed for pain progression (p = ns) and late PF occurrence (p = ns).ConclusionProphylactic corticosteroids reduced the incidence of early PF, the days with PF, resulting in a superior rate of patients with no PF and no pain progression, but with no significant benefit for reducing pain progression or late PF occurrence. 相似文献
996.
Echeverri Lina Maria Salazar Moraes Julio Cesar de Lourdes Borba Magalhães Maria Da Silva Gustavo Felippe 《International journal of peptide research and therapeutics》2021,27(1):1-7
International Journal of Peptide Research and Therapeutics - A peptide Phage Display library was constructed using the BTK2 toxin as scaffold and rolling cycle amplification combined with Kunkel... 相似文献
997.
Christchellyn Klegin Neusa Fernandes de Moura Matheus Henrique Oliveira de Sousa Rafaele Frassini Mariana Roesch-Ely Alessandra Nejar Bruno Thais Cardoso Bitencourt Adriana Flach Juçara Bordin 《化学与生物多样性》2021,18(3):e2000794
The present study aimed to determine the chemical composition and biological activity of the essential oil obtained from Phyllogonium viride Brid. (Phyllogoniaceae, Bryophyta), whose samples were collected in southern Brazil. For the first time, the cytotoxic activity of the essential oil of P. viride in breast and colorectal tumor cells (MCF-7 and HCT-116) was evaluated, as well as the cytotoxic potential of this oil in non-tumoral cells of human immortalized keratinocytes (HaCaT) via MTT assay. The compounds majorly found in P. viride essential oil were β-bazzanene (20.30 %), β-caryophyllene (17.06 %), β-chamigrene (14.02), and germacrene B (11.72 %). Treatment with P. viride essential oil in the different tested cell lines did not induce any toxicity in most of the tested concentrations. These data contribute to generating new scientific information about this understudied plant species. Furthermore, the chemical characterization of the compounds present in the essential oil of P. viride can lead to greater elucidation of its biotechnological potential. 相似文献
998.
Geisiane Amorim de Brito Paulo Fernando Rocha de Oliveira Caliene Melo de Andrade Silva Moysés Fagundes de Araújo Neto Franco Henrique Andrade Leite Paulo Roberto Ribeiro Mesquita Tiago Feitosa Mota Jairo Torres Magalhães-Junior 《化学与生物多样性》2021,18(9):e2100242
Most of the hematophagous insects act as disease vectors, including Aedes aegypti, responsible for transmitting some of the most critical arboviruses globally, such as Dengue. The use of repellents based on natural products is a promising alternative for personal protection compared to industrial chemical repellents. In this study, the repellent effect of essential oils extracted from Lippia thymoides, Lippia alba, Cymbopogon winterianus, and Eucalyptus globulus leaves was evaluated. Essential oils used showed repellent activity against Ae. aegypti in laboratory bioassays, obtaining protection rates above 70 % from 3.75 mg/mL and higher concentration for all analyzed oils. GC/MS identified 57 constituents, which were used in the ligand-based pharmacophore model to expose compounds with requirements for repellents that modulate mosquitoes behavior through odorant-binding protein 1 Ae. aegypti. Ligand-based pharmacophore model approach results suggested that repellent activity from C. winterianus, L. alba, and L. thymoides essential oils’ metabolites is related to Citronelal (QFIT=26.77), Citronelol (QFIT=11.29), Citronelol acetate (QFIT=52.22) and Geranil acetate (QFIT=10.28) with synergistic or individual activity. E. globulus essential oil's repellent activity is associated with Ledol (0.94 %; QFIT=41.95). Molecular docking was applied to understand the binding mode and affinity of the essential oils’ data set at the protein binding site. According to molecular docking, Citronelol (ChemPLP=60.98) and geranyl acetate (ChemPLP=60.55) were the best-classified compounds compared to the others and they can be explored to develop new repellents. 相似文献
999.
Waicheim María Agustina Mendes Marques Taísa Rauque Carlos Alejandro Viozzi Gustavo 《Systematic parasitology》2021,98(2):131-139
Systematic Parasitology - A new parasitic copepod, Ergasilus yandemontei n. sp., is described based on 10 adult females collected from the gills of the atherinid silverside Odontesthes hatcheri... 相似文献
1000.
Soares Mayara Sandrielly Pereira Luduvico Karina Pereira Chaves Vitor Clasen Spohr Luiza Meine Bernardo de Moraes Lencina Claiton Leoneti Reginatto Flávio Henrique Spanevello Roselia Maria Simões Cláudia Maria Oliveira Stefanello Francieli Moro 《Neurochemical research》2021,46(5):1129-1140
Neurochemical Research - Neuroinflammation is an event that occurs in several pathologies of brain. Rubus sp. (blackberry) is a powerful antioxidant fruit, and its extract has neuroprotective... 相似文献