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471.
Ana Margarida Sousa Idalina MachadoAna Nicolau Maria Olívia Pereira 《Journal of microbiological methods》2013
Colony morphology may be an indicator of phenotypic variation, this being an important adaptive process adopted by bacteria to overcome environmental stressors. Furthermore, alterations in colony traits may reflect increased virulence and antimicrobial resistance. Despite the potential relevance of using colony morphological traits, the influence of experimental conditions on colony morphogenesis has been scarcely studied in detail. This study aims to clearly and systematically demonstrate the impact of some variables, such as colony growth time, plate colony density, culture medium, planktonic or biofilm mode of growth and strain genetic background, on bacterial colony morphology features using two Pseudomonas aeruginosa strains. Results, based on 5-replicate experiments, demonstrated that all variables influenced colony morphogenesis and 18 different morphotypes were identified, showing different sizes, forms, colours, textures and margins. Colony growth time and composition of the medium were the variables that caused the highest impact on colony differentiation both derived from planktonic and biofilm cultures. Colony morphology characterization before 45 h of incubation was considered inadequate and TSA, a non-selective medium, provided more colony diversity in contrast to P. aeruginosa selective media. In conclusion, data obtained emphasized the need to perform comparisons between colony morphologies in equivalent experimental conditions to avoid misinterpretation of microbial diagnostics and biomedical studies. Since colony morphotyping showed to be a reliable method to evaluate phenotypic switching and also to infer about bacterial diversity in biofilms, these unambiguous comparisons between morphotypes may offer a quite valuable input to clinical diagnosis, aiding the decision-making towards the selection of the most suitable antibiotic and supportive treatments. 相似文献
472.
Zedenil Rodrigues Mendes Antonio Domingos Brescovit Maria Margarida Rocha Fiuza de Mello Maria das Graças Lapa Wanderley 《Studies on Neotropical Fauna and Environment》2013,48(3):184-193
The vegetative architecture of the Cactaceae provides sites used by spiders as hideout, foraging, mating and oviposition. We found more web weavers in plants with cylindrical cladodia and more hunters in plants with flat cladodia. Between February 2014 and January 2015 1551 spiders distributed in 20 families were collected: one of these families, Palpimanidae, had only juvenile individuals collected; of the other 19 families, 80 species/morphospecies were identified. This work aims to contribute to the knowledge of biodiversity in the canopy of the Atlantic Forest, especially the relationship between cacti and spiders. 相似文献
473.
474.
Brito JA Bandeiras TM Teixeira M Vonrhein C Archer M 《Biochimica et biophysica acta》2006,1764(4):842-845
NADH:quinone oxidoreductases (NDHs), constitute one of the electron entry points into membrane-bound respiratory chains, oxidising NADH and reducing quinones. Type-II NDHs (NDH-2) are functionally unable to translocate protons and are typically constituted by a single approximately 50 kDa subunit lacking iron-sulfur clusters and containing one flavin as the sole redox centre. No three dimensional crystal structure is yet available for NDHs. We describe the crystallisation and preliminary structure determination of a NDH-2 that contains a covalently bound FAD, isolated from the membrane fraction of Acidianus ambivalens, a hyperthermoacidophilic archaeon capable of growing at 80 degrees C and pH 2.0. NDH-2 was solubilised with the detergent n-dodecyl-beta-d-maltoside and crystallised using ammonium phosphate as precipitant. The structure was solved by MIRAS using Pt and I derivatives. 相似文献
475.
Every year, forty percent of the world population is at risk of contracting malaria. Hopes for the erradication of this disease during the 20th century were dashed by the ability of Plasmodium falciparum, its most deadly causative agent, to develop resistance to available drugs. Efforts to produce an effective vaccine have so far been unsuccessful, enhancing the need to develop novel antimalarial drugs. In this review, we summarize our knowledge concerning existing antimalarials, mechanisms of drug-resistance development, the use of drug combination strategies and the quest for novel anti-plasmodial compounds. We emphasize the potential role of host genes and molecules as novel targets for newly developed drugs. Recent results from our laboratory have shown Hepatocyte Growth Factor/MET signaling to be essential for the establishment of infection in hepatocytes. We discuss the potential use of this pathway in the prophylaxis of malaria infection. 相似文献
476.
477.
Esteves SL Domingues SC da Cruz e Silva OA Fardilha M da Cruz e Silva EF 《Omics : a journal of integrative biology》2012,16(1-2):3-17
Protein Phosphatase 1 (PP1) is a major serine/threonine-phosphatase whose activity is dependent on its binding to regulatory subunits known as PP1 interacting proteins (PIPs), responsible for targeting PP1 to a specific cellular location, specifying its substrate or regulating its action. Today, more than 200 PIPs have been described involving PP1 in panoply of cellular mechanisms. Moreover, several PIPs have been identified that are tissue and event specific. In addition, the diversity of PP1/PIP complexes can further be achieved by the existence of several PP1 isoforms that can bind preferentially to a certain PIP. Thus, PP1/PIP complexes are highly specific for a particular function in the cell, and as such, they are excellent pharmacological targets. Hence, an in-depth survey was taken to identify specific PP1α PIPs in human brain by a high-throughput Yeast Two-Hybrid approach. Sixty-six proteins were recognized to bind PP1α, 39 being novel PIPs. A large protein interaction databases search was also performed to integrate with the results of the PP1α Human Brain Yeast Two-Hybrid and a total of 246 interactions were retrieved. 相似文献
478.
Carlos A. Fernandes Mónica Rodrigues Ghaiet M. Hajji Paul Vercammen Michael W. Bruford Margarida Santos-Reis 《Conservation Genetics》2009,10(6):1931-1934
We report the isolation and characterization of 11 polymorphic tetranucleotide microsatellite loci in the common genet (Genetta genetta) from genomic libraries enriched for (AAAG)
n
and (AGAT)
n
repeat sequences. We chose to develop tetranucleotide repeats because they can be scored less ambiguously. In a sample of
25 individuals, we observed between four and thirteen alleles per locus and their observed and expected heterozygosities ranged
from 0.60 to 0.84 and from 0.68 to 0.92, respectively. All genotypic frequencies conformed to Hardy–Weinberg equilibrium expectations
and there were no instances of linkage disequilibrium detected between pairs of loci. These loci will be of use in studies
of population genetics, historical demography, and molecular ecology of the common genet. 相似文献
479.
Pedro Simões Marta Pascual Josiane Santos Michael R Rose Margarida Matos 《BMC evolutionary biology》2009,9(1):133-3
Here we present a correction to our article "Evolutionary dynamics of molecular markers during local adaptation: a case study
in Drosophila subobscura ". We have recently detected an error concerning the application of the Ln RH formula – a test to detect positive selection
– to our microsatellite data. Here we provide the corrected data and discuss its implications for our overall findings. The
corrections presented here have produced some changes relative to our previous results, namely in a locus (dsub14) that presents indications of being affected by positive selection. In general, our populations present less consistent indications
of positive selection for this particular locus in both periods studied – between generations 3 and 14 and between generation
14 and 40 of laboratory adaptation. Despite this, the main findings of our study regarding the possibility of positive selection
acting on that particular microsatellite still hold. As previously concluded in our article, further studies should be performed
on this specific microsatellite locus (and neighboring areas) to elucidate in greater detail the evolutionary forces acting
on this specific region of the O chromosome of Drosophila subobscura. 相似文献
480.
Margarida Coelho Fernando Sequeira Donata Luiselli Sandra Beleza Jorge Rocha 《BMC evolutionary biology》2009,9(1):80