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991.
Amaral Suélen Cavalheiro Pruski Beatriz Bohns de Freitas Stella Buchhorn Allend Suzane Olachea Ferreira Marcos Roberto Alves Moreira Clóvis Pereira Daniela Isabel Brayer Junior Antonio Sergio Varela Hartwig Daiane Drawanz 《Molecular biology reports》2020,47(12):9615-9625
Molecular Biology Reports - Antimicrobial resistance is increasing around the world and the search for effective treatment options, such as new antibiotics and combination therapy is urgently... 相似文献
992.
993.
In the present paper the formation of complexes between positively charge polyelectrolyte (polyethyleneimine and chitosan) and Candida rugosa lipase from a crude extract and porcine lipase from pancreas commercial homogenate preparations were analyzed. The solubility of lipases-cationic polyelectrolytes formation was dependent on: polyelectrolyte densities electrical charge, polyelectrolyte and enzyme concentrations and salts present in the solution. The lipase was recovered from the non-soluble complex by adding of NaCl at a given pH. Although the polyelectrolytes did not affect lipase biological activity, both of them produced good enzyme recovery (>90%); however, purification factors were low. This methodology appears to be a good previous prepurification and concentration method, using, low-cost polymers, allows the design of a purification method where the protein of interest is present in a large volume with respect to the small amount of polyelectrolyte added. 相似文献
994.
Vieites M Smircich P Pagano M Otero L Fischer FL Terenzi H Prieto MJ Moreno V Garat B Gambino D 《Journal of inorganic biochemistry》2011,105(12):1704-1711
In the search for drugs with anti-trypanosome activity, we had previously synthesized two series of platinum and palladium analogous compounds of the formula [MIICl2(HL)], where HL were bioactive 5-nitrofuryl or 5-nitroacroleine thiosemicarbazone derivatives. In this work, we thoroughly characterized [MIICl2(HL)] complexes interaction with DNA by using different techniques: gel electrophoresis, DNA viscosity measurements, circular dichroism (CD) and atomic force microscopy (AFM). Electrophoresis results showed that all complexes induced a withdrawal of DNA superhelicity demonstrated by a decrease in electrophoretic mobility of supercoiled DNA form. This effect on migration was dependent on dose but also on the nature of both the metal and the ligand. In general, the effect produced by palladium complexes was significantly more intense than that observed for the corresponding platinum analogs. Differences between palladium and platinum complexes were also observed in CD experiments. While palladium complexes induce evident calf thymus (CT)-DNA profile changes compatible with B-DNA to Z-DNA conformational transition, no clear effect was observed for platinum ones. Additionally, AFM studies showed that changes in the shape of plasmid DNA, like supercoiling, kinks and thickness increase resulted more intense for the former. In addition, either Pd or Pt complexes increased the viscosity of CT DNA solutions in a concentration dependent manner. Although the nature of DNA interaction of both series of analogous palladium and platinum complexes seemed to be similar, an explanation for the observed differential intensity of the effect could be related to the known kinetic stability differences between palladium and platinum compounds. 相似文献
995.
Nei K. Leite Alex V. Krusche Maria V. R. Ballester Reynaldo L. Victoria Jeffrey E. Richey Beatriz M. Gomes 《Biogeochemistry》2011,105(1-3):37-51
Concentrations of cations (Na+, Ca2+, Mg2+, K+, NH4 +), anions (HCO3 ?, Cl?,?NO3 ?, SO4 2?, PO4 3?) and suspended sediments in the Madeira River water were?determined near the city of Porto Velho (RO), in order to assess variation in?water chemistry from 2004 to 2007. Calcium and bicarbonate were the dominant?cation and anion, respectively. Significant seasonal differences were found,?with highest concentrations occurring during the dry season, as expected from?the drainage of Andean carbonate-rich substratum. Interannual variations were?also observed, but became significant only when annual average discharge was?25% less than normal. Under this atypical discharge condition, bicarbonate was?replaced by sulfate, and higher suspended sediment concentrations and loads?were also observed. Compared to previously published studies, it appears that?no significant changes in water chemistry have occurred during the last 20?C30?years, although differences in approaches and sampling designs among this and previous studies may not allow detection of modest changes.?The calculated suspended sediment load reported here is close to the values presented elsewhere, reinforcing the relative importance of this river as a?sediment supplier for the Amazon Basin. Seasonality has a significant control?on the chemistry of Madeira River waters, and severe decrease in discharge due?to anthropogenic changes, such as construction of reservoirs or the occurrence?of drier years??a plausible consequence of global climate change??may lead?to modification in the chemical composition as well in the sediment deliver to?the Amazon River. 相似文献
996.
Ayala C Valdez SR Morero ML Soaje M Carreño NB Sanchez MS Bittencourt JC Jahn GA Celis ME 《Peptides》2011,32(6):1249-1254
To date, there has been only one in vitro study of the relationship between neuropeptide EI (NEI) and the hypothalamic-pituitary-thyroid (HPT) axis. To investigate the possible relationship between NEI and the HPT axis, we developed a rat model of hypothyroidism and hyperthyroidism that allows us to determine whether NEI content is altered in selected brain areas after treatment, as well as whether such alterations are related to the time of day. Hypothyroidism and hyperthyroidism, induced in male rats, with 6-propyl-1-thiouracil and l-thyroxine, respectively, were confirmed by determination of triiodothyronine, total thyroxine, and thyrotropin levels. All groups were studied at the morning and the afternoon. In rats with hypothyroidism, NEI concentration, evaluated on postinduction days 7 and 24, was unchanged or slightly elevated on day 7 but was decreased on day 24. In rats with hyperthyroidism, NEI content, which was evaluated after 4 days of l-thyroxine administration, was slightly elevated, principally in the preoptic area in the morning and in the median eminence-arcuate nucleus and pineal gland in the afternoon, the morning and afternoon NEI contents being similar in the controls. These results provide the bases to pursue the study of the interaction between NEI and the HPT axis. 相似文献
997.
998.
Gutiérrez D Martín-Platero AM Rodríguez A Martínez-Bueno M García P Martínez B 《FEMS microbiology letters》2011,322(1):90-97
The recent boom in phage therapy and phage biocontrol requires the design of suitable cocktails of genetically different bacteriophages. The current methods for typing phages need significant quantities of purified DNA, may require a priori genetic information and are cost and time consuming. We have evaluated the randomly amplified polymorphic DNA (RAPD)-PCR technique to produce unique and reproducible band patterns from 26 different bacteriophages infecting Staphylococcus epidermidis, Staphylococcus aureus, Lactococcus lactis, Escherichia coli, Streptococcus thermophilus, Bacillus subtilis and Lactobacillus casei bacterial strains. Initially, purified DNA and phage suspensions of seven selected phages were used as a template. The conditions that were found to be optimal 8 μM of 10-mer primers, 3 μM magnesium oxalacetate and 5% dimethyl sulfoxide. The RAPD genomic fingerprints using a phage titer suspension higher than 10(9) PFU mL(-1) were highly reproducible. Clustering by the Pearson correlation coefficient and the unweighted pair group method with arithmetic averages clustering algorithm correlated largely with genetically different phages infecting the same bacterial species, although closely related phages with a similar DNA restriction pattern were indistinguishable. The results support the use of RAPD-PCR for quick typing of phage isolates and preliminary assessment of their genetic diversity bypassing tedious DNA purification protocols and previous knowledge of their sequence. 相似文献
999.
1000.
Branco AT Dos Santos Ferreira B Lourenço GF Lopes Marques VC Tavares Machado OL Pereira MG Aquino Almeida JC de Souza Filho GA 《Protein and peptide letters》2011,18(7):651-657
β-1,3-glucanases are found in organisms as diverse as plants, animals, bacteria and fungi. In plants, such enzymes are not only associated with defense mechanisms against pathogens, but also play critical roles in physiological and developmental processes. Here we identified a new β-1,3-glucanase in maize seeds, and named it ZmGlucA. Sequence analysis revealed that ZmGlucA belongs to the class A of β-1,3-glucanase, a class related to defense and physiological processes in plants. mRNA and protein assays showed that zmGlucA is expressed exclusively in seeds, and it is differentially regulated during seed development. Additionally, zmGlucA expression is strongly induced in seeds of the mutant dek 827Kpro1, which is defective for embryo and endosperm development. Our data support the idea that ZmGlucA protein is relevant to seed development. 相似文献