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851.
Jonny E. Scherwinski-Pereira Rodrigo S. da Guedes Paulo César P. FerminoJr Tatiane L. Silva Frederico Henrique S. Costa 《In vitro cellular & developmental biology. Plant》2010,46(4):378-385
An efficient procedure has been developed for inducing somatic embryogenesis and regeneration of plants from tissue cultures
of oil palm (Elaeis guineensis Jacq.). Thin transverse sections (thin cell layer explants) of different position in the shoot apex and leaf sheath of oil
palm were cultivated in Murashige and Skoog (MS) (Physiol Plant 15:473–497, 1962) medium supplemented with 0–450 μM picloram and 2,4-D with 3.0% sucrose, 500 mg L−1 glutamine, and 0.3 g L−1 activated charcoal and gelled with 2.5 g L−1 Phytagel. Embryogenic calluses were evaluated 12 wk after inoculation. Picloram (450 μM) was effective in inducing embryogenic
calluses in 41.5% of the basal explants. Embryogenic calluses were maintained on a maturation medium composed of basal media,
plus 0.6 μM NAA and 12.30 μM 2iP, 0.3 g L−1 activated charcoal, and 500 mg L−1 glutamine, with subcultures at 4-wk intervals. Somatic embryos were converted to plants on MS medium with macro- and micronutrients
at half-strength, 2% sucrose, and 1.0 g L−1 activated charcoal and gelled with 2.5 g L−1 Phytagel. 相似文献
852.
Ana Flávia Azevedo Carvalho Maurício Boscolo Roberto da Silva Henrique Ferreira Eleni Gomes 《Journal of microbiology (Seoul, Korea)》2010,48(4):452-459
An α-glucosidase enzyme produced by the fungus Thermoascus aurantiacus CBMAI 756 was purified by ultra filtration, ammonium sulphate precipitation, and chromatography using Q Sepharose, Sephacryl
S-200, and Superose 12 columns. The apparent molecular mass of the enzyme was 83 kDa as determined in gel electrophoresis.
Maximum activity was observed at pH 4.5 at 70°C. Enzyme showed stability stable in the pH range of 3.0–9.0 and lost 40% of
its initial activity at the temperatures of 40, 50, and 60°C. In the presence of ions Na+, Ba2+, Co2+, Ni2+, Mg2+, Mn2+, Al3+, Zn2+, Ca2+ this enzyme maintained 90–105% of its maximum activity and was inhibited by Cr3+, Ag+, and Hg2+. The enzyme showed a transglycosylation property, by the release of oligosaccharides after 3 h of incubation with maltose,
and specificity for short maltooligosaccharides and α-PNPG. The Km measured for the α-glucosidase was 0.07 μM, with a Vmax of 318.0 μmol/min/mg. 相似文献
853.
Rosângela M. R. Barbosa Andre Furtado Lêda Regis Walter S. Leal 《Journal of vector ecology》2010,35(1):204-207
A synthetic mixture of an oviposition‐stimulating kairomone for the yellow fever mosquito, Aedes aegypti, comprising of 83% tetradecanoic acid, 16% nonanoic acid and 1% tetradecanoic acid methyl ester (NTT, in short) was tested in a dengue endemic area in Recife, Brazil. Gravid female mosquitoes confined to a cage under semi‐field conditions deposited significantly higher numbers of eggs in traps baited with NTT at doses ranging from 0.6 to 600 ng/μl than in control (water) traps. When tested in homes, egg‐laying in traps baited with 60 ng NTT/μl (final concentration in trap, ≈3.33 ng/ml) and in control traps was not significantly different, but egg deposited in traps with lower dosage (6 ng NTT/μl; final concentration in trap, ≈0.33 ng/ml) was significantly higher than in control traps. In subsequent trials, the numbers of eggs laid in traps baited with 0.6 ng NTT/μl (final concentration in trap, ≈0.033 ng/ml) were not significantly different from the numbers deposited in trap loaded with 6 ng NTT/μl. Egg‐laying was significantly higher in these treatments than in control traps. 相似文献
854.
Chris Smillie M. Pilar Garcill��n-Barcia M. Victoria Francia Eduardo P. C. Rocha Fernando de la Cruz 《Microbiology and molecular biology reviews》2010,74(3):434-452
Summary: Plasmids are key vectors of horizontal gene transfer and essential genetic engineering tools. They code for genes involved in many aspects of microbial biology, including detoxication, virulence, ecological interactions, and antibiotic resistance. While many studies have decorticated the mechanisms of mobility in model plasmids, the identification and characterization of plasmid mobility from genome data are unexplored. By reviewing the available data and literature, we established a computational protocol to identify and classify conjugation and mobilization genetic modules in 1,730 plasmids. This allowed the accurate classification of proteobacterial conjugative or mobilizable systems in a combination of four mating pair formation and six relaxase families. The available evidence suggests that half of the plasmids are nonmobilizable and that half of the remaining plasmids are conjugative. Some conjugative systems are much more abundant than others and preferably associated with some clades or plasmid sizes. Most very large plasmids are nonmobilizable, with evidence of ongoing domestication into secondary chromosomes. The evolution of conjugation elements shows ancient divergence between mobility systems, with relaxases and type IV coupling proteins (T4CPs) often following separate paths from type IV secretion systems. Phylogenetic patterns of mobility proteins are consistent with the phylogeny of the host prokaryotes, suggesting that plasmid mobility is in general circumscribed within large clades. Our survey suggests the existence of unsuspected new relaxases in archaea and new conjugation systems in cyanobacteria and actinobacteria. Few genes, e.g., T4CPs, relaxases, and VirB4, are at the core of plasmid conjugation, and together with accessory genes, they have evolved into specific systems adapted to specific physiological and ecological contexts. 相似文献
855.
Helena de Freitas Oliveira Paranhos Claudia Helena Lovato da Silva Raphael Freitas De Souza Karina Matthes de Freitas Pontes 《Gerodontology》2010,27(1):33-40
doi:10.1111/j.1741‐2358.2009.00285.x Evaluation of three indices for biofilm accumulation on complete dentures Objectives: The objective of this study was to evaluate the accuracy and reproducibility of three complete denture biofilm indices (Prosthesis Hygiene Index; Jeganathan et al. Index; Budtz‐Jørgensen Index) by means of a computerised comparison method. Background: Clinical studies into denture hygiene have employed a large number of biofilm indices among their outcome variables. However, the knowledge about the validity of these indices is still scarce. Materials and methods: Sixty‐two complete denture wearers were selected. The internal surfaces of the upper complete dentures were stained (5% erythrosine) and photographed. The slides were projected on paper, and the biofilm indices were applied over the photos by means of a scoring method. For the computerised method, the areas (total and biofilm‐covered) were measured by dedicated software (Image Tool). In addition, to compare the results of the computerised method and Prosthetic Hygiene Index, a new scoring scale (including four and five graded) was introduced. For the Jeganathan et al. and Budtz‐Jørgensen indices, the original scales were used. Values for each index were compared with the computerised method by the Friedman test. Their reproducibility was measured by means of weighed κ. Significance for both tests was set at 0.05. Results: The indices tested provided similar mean measures but they tended to overestimate biofilm coverage when compared with the computerised method (p < 0.001). Agreement between the Prosthesis Hygiene Index and the computerised method was not significant, regardless of the scale used. Jeghanathan et al. Index showed weak agreement, and consistent results were found for Budtz‐Jorgensen Index (κ = 0.19 and 0.39 respectively). Conclusion: Assessment of accuracy for the biofilm indices showed instrument bias that was similar among the tested methods. Weak inter‐instrument reproducibility was found for the indices, except for the Budtz‐Jørgensen Index. This should be the method of choice for clinical studies when more sophisticated approaches are not possible. 相似文献
856.
Eder Jorge de Oliveira Vanusia Batista Oliveira Amorim Edneide Luciana Santiago Matos Juliana Leles Costa Milene da Silva Castellen Juliano Gomes Pádua Jorge Luiz Loyola Dantas 《Plant Molecular Biology Reporter》2010,28(3):519-530
A set of 81 new microsatellite markers for Carica papaya L. previously identified by data mining using freely available sequence information from Genbank were tested for polymorphism
using 30 germplasm accessions from the Papaya Germplasm Bank (PGM) at Embrapa Mandioca e Fruticultura Tropical (CNPMF) and
18 landraces. The data were used to estimate pairwise genetic distances between the genotypes. A neighbor-joining based dendrogram
was used to define clusters and infer possible genetic structuring of the collection. Most microsatellites were polymorphic
(73%), with an observed number of alleles per locus ranging from one to eleven. The levels of observed and expected heterozygosity
for 51 polymorphic loci varied from 0.00 to 0.85 and from 0.08 to 0.82, averaging 0.19 and 0.59, respectively. Forty-four
percent of microsatellites showed polymorphism information content (PIC) higher than 0.50. The compound microsatellites seem
to be more informative than dinucleotide and trinucleotide repeats in average alleles per locus and PIC. Among dinucleotides,
AG/TC or GA/CT repeat motifs exhibited more informativeness than TA/AT, GT/CA and TG/AC repeat motifs. The neighbor-joining
analysis based on shared allele distance could differentiate all the papaya accessions and landraces as well as differences
in their genetic structure. This set of markers will be useful for examining parentage, inbreeding and population structure
in papaya. 相似文献
857.
Maria E. Silva Serra Dina Murtinho Albertino Goth António M. D'A. Rocha Gonsalves Paulo E. Abreu Alberto A. C. C. Pais 《Chirality》2010,22(4):425-431
New chiral salen ligands were prepared by the ultrasound‐irradiated condensation of optically active (1R, 3S)‐1,2,2‐trimethyl‐1,3‐diaminocyclopentane with aromatic 1‐hydroxyaldehydes. The ultrasound‐mediated process is more convenient due to shorter reaction times, energy economy, and easier isolation of the products. The in situ formed Ti(IV)(salen) complexes, evaluated as catalysts in the enantioselective trimethylsilylcyanation of benzaldehyde, were found to be efficient for this process, originating the corresponding product in high yields (72–99%) and selectivities of up to 79%. The lowest energy transition states were determined by computational studies. These results were in qualitative agreement with the experimentally observed ones. Chirality, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
858.
Brito de Souza VN Nogueira ME Belone Ade F Soares CT 《FEMS immunology and medical microbiology》2010,60(3):270-274
Apoptosis eliminates pathogen-infected cells. Its modulation can influence the course of infections, permitting the survival of intracellular pathogens. In leprosy, which presents several clinical manifestations related to bacillary burden and host immune status, the mechanisms responsible for the persistence of the bacillus are unknown. Few studies have focused on apoptosis over the disease spectrum and as a defense mechanism against Mycobacterium leprae. We evaluated apoptosis using terminal transferase dUTP nick end labeling and the expression of Bcl-2 by immunohistochemistry in skin lesions from 11 tuberculoid and 15 lepromatous leprosy patients. Each specimen was evaluated by determining the number of positive cells in 10 fields at × 400 magnification. We observed a higher number of apoptotic cells in tuberculoid lesions in comparison with lepromatous leprosy (42.5 cells per 10 fields vs. 11.5 cells per 10 fields, P<0.0001). Expression of Bcl-2, conversely, was larger in lepromatous than in tuberculoid samples (172.0 cells per 10 fields vs. 17.7 cells per 10 fields, P<0.0001). These observations suggest modulation of apoptosis in leprosy, primarily in lepromatous patients, for which the decrease in cell death could support M. leprae survival and contribute to the success of infection. Conversely, in tuberculoid patients, apoptosis could contribute to reducing propagation of the bacillus. 相似文献
859.
Maria Cristina Sanches Sérvio Pontes Ribeiro Valdnéa Casagrande Dalvi Milton Barbosa da Silva Junior Hildeberto Caldas de Sousa José Pires de Lemos-Filho 《Trees - Structure and Function》2010,24(1):79-88
Cariniana legalis is an emergent tree that reaches the upper canopy in Brazilian Semideciduous Forest. Spatial contrasts in microclimatic conditions
between the upper canopy and understorey in a forest may affect morpho-physiological leaf traits. In order to test the hypothesis
that the upper canopy is more stressful to leaves than a gap environment we compared emergent trees of C. legalis, 28–29 m in height to gap saplings, 6–9 m in height, for the following parameters: leaf area, leaf mass area (LMA the dry
weight:leaf area ratio), leaf thickness, leaf anatomical parameters, stomata conductance, and chlorophyll a fluorescence. Leaves from emergent trees had smaller leaf areas but greater LMA compared to saplings. Leaf thickness, palisade
layer thickness, and stomatal density were higher for emergent trees than for saplings. The opposite pattern was observed
for spongy layer thickness and spongy/palisade ratio. Stomatal conductance was also higher for emergent tree leaves than for
sapling leaves, but the magnitude of depression on stomatal conductance near midday was more pronounced in emergent trees.
The potential quantum yield of photosystem II, as determined by the F
v/F
m ratio was lower for leaves from saplings. The lower values of stomatal conductance, indicating restriction in CO2 diffusion into the mesophyll can be related to higher photoinhibition observed in the saplings. Leaves from emergent trees
and saplings exhibited similar values for apparent electron transport rates and non-photochemical quenching. Our results suggest
that changes in leaf traits could be associated to dry conditions at the upper canopy as well as to the ontogenetic transition
between sapling/emergent tree life stages. 相似文献
860.
Microbial communities and chemical changes during fermentation of sugary Brazilian kefir 总被引:2,自引:0,他引:2
Karina Teixeira Magalhães G. V. de M. Pereira Disney Ribeiro Dias Rosane Freitas Schwan 《World journal of microbiology & biotechnology》2010,26(7):1241-1250
The microorganisms associated with sugary Brazilian kefir beverage were investigated using a combination of culture-dependent
and -independent methods. A total of 289 bacteria and 129 yeasts were identified via phenotypic and genotypic methods. Lb. paracasei (23.8%) was the major bacterial isolate identified, followed by Acetobacter
lovaniensis (16.31%), Lactobacillus parabuchneri (11.71%), Lactobacillus kefir (10.03%) and Lactococcus lactis (10.03%). Saccharomyces cerevisiae (54.26%) and Kluyveromyces lactis (20.15%) were the most common yeast species isolated. Scanning electron microscopy showed that the microbiota was dominated
by lemon-shaped yeast cells growing in close association with Lactobacillus (long and curved). Some lactic acid bacteria detected by sequence analysis of DGGE (denaturing gradient gel electrophoresis)
bands were not recovered at any time through fermentation by plating. Conversely, DGGE fingerprints did not reveal bands corresponding
to some of the species isolated by culturing methods. The bacteria Acetobacter lovaniensis and the yeast Kazachstania aerobia are described for the first time in sugary kefir. During the 24 h of fermentation, the concentration of lactic acid ranged
from 0.2 to 1.80 mg/ml, and that of acetic acid increased from 0.08 to 1.12 mg/ml. The production of ethanol was limited,
reaching a final mean value of 1.24 mg/ml. 相似文献