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61.
Beadell JS Ishtiaq F Covas R Melo M Warren BH Atkinson CT Bensch S Graves GR Jhala YV Peirce MA Rahmani AR Fonseca DM Fleischer RC 《Proceedings. Biological sciences / The Royal Society》2006,273(1604):2935-2944
The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite within a global ecological and evolutionary context. Using fragments of the parasite mitochondrial gene cytochrome b and the nuclear gene dihydrofolate reductase-thymidylate synthase obtained from a global survey of greater than 13000 avian samples, we show that Hawaii's avian malaria, which can cause high mortality and is a major limiting factor for many species of native passerines, represents just one of the numerous lineages composing the morphological parasite species. The single parasite lineage detected in Hawaii exhibits a broad host distribution worldwide and is dominant on several other remote oceanic islands, including Bermuda and Moorea, French Polynesia. The rarity of this lineage in the continental New World and the restriction of closely related lineages to the Old World suggest limitations to the transmission of reproductively isolated parasite groups within the morphological species. 相似文献
62.
Alcione Miotto Carlos A. Ceretta Gustavo Brunetto Fernando T. Nicoloso Eduardo Girotto Júlia G. Farias Tadeu L. Tiecher Lessandro De Conti Gustavo Trentin 《Plant and Soil》2014,374(1-2):593-610
Aims
This study investigated Cu uptake and accumulation as well as physiological and biochemical changes in grapevines grown in soils containing excess Cu.Methods
The grapevines were collected during two productive cycles from three vineyards with increasing concentrations of Cu in the soil and at various growth stages, before and after the application of Cu-based fungicides. The Cu concentrations in the grapevine organs and the macronutrients and biochemical parameters in the leaf blades were analyzed.Results
At close to the flowering stage of the grapevines, the concentration and content of Cu in the leaves were increased. However, the Cu concentrations in the roots, stem, shoots and bunches did not correlate with the metal concentrations in the soil. The application of Cu-based fungicides to the leaves increased the Cu concentrations in the shoots, leaves and rachis; however, the effect of the fungicides on the Cu concentration in the berries was not significant. The biochemical analyses of the leaf blades demonstrated symptoms of oxidative stress that correlated with the Cu concentrations in soil.Conclusions
The increased availability of Cu in soil had a slight effect on the levels and accumulation of Cu in mature grapevines during the productive season and did not alter the nutritional status of the plant. However, increased Cu concentrations were observed in the leaves. The evidence of oxidative stress in the leaves correlated with the increased levels of Cu in soil. 相似文献63.
Dimas Mendes Ribeiro Ana Maria Mapeli Carla Andréa Delatorre Marcelo Augusto Gutierrez Carnelossi Raimundo Santos Barros 《Acta Physiologiae Plantarum》2011,33(6):2117-2123
Dormancy of scarified seeds of Stylosanthes humilis was broken by acidic Al3+ and Fe3+ solutions. Fe+3-stimulated seeds exhibited a high activity of 1-aminocyclopropane-1-carboxylate (ACC) oxidase and produced great amounts
of ethylene, which showed correlated with the germination process. In addition, specific inhibitors of ethylene biosynthesis
and action largely depressed the Fe3+-stimulated germination, leading to the conclusion that the ion broke dormancy by triggering ethylene production by the seeds.
By contrast, inhibitors of ethylene biosynthesis and action did not impair germination of Al3+-stimulated dormant seeds. Moreover, ethylene production and activity of ACC oxidase of Al3+-treated seeds was substantially decreased by inhibitors of ethylene biosynthesis, but germination kept large. Together these
data suggest that ethylene biosynthesis was not required in the chain of events triggered by Al3+ leading to dormancy breakage. Methyl viologen (MV), a reactive oxygen species-generating compound, broke dormancy of seeds
to the same extent as Al3+ did. Germination of both Al3+- and MV-stimulated dormant seeds was inhibited by sodium selenate, an antioxidant compound; selenate, however had no effect
on germination of Fe3+-stimulated seeds. Together these data indicate that the mechanisms underlying the germination of Al3+- and Fe3+-treated seeds are not the same. 相似文献
64.
França K Villa RT Bastos VR Almeida AC Massucatti K Fukumaru D Bedin V 《Mycopathologia》2011,172(1):69-72
Subcutaneous chromoblastomycosis is an infection commonly seen in tropical and subtropical climates, usually caused by trauma
with vegetables and often affects the host’s lower limbs. We report a case of auricular chromoblastomycosis in a 67-year-old
man and discuss the rarity of this clinical manifestation of chromoblastomycosis in the medical literature. In the present
case, the etiologic agent was Fonsecaea pedrosoi, the most common agent found in Brazil. 相似文献
65.
Paula F. T. Cezar-de-Mello Thiago G. Toledo-Pinto Carolinne S. Marques Lucia E. A. Arnez Cynthia C. Cardoso Luana T. A. Guerreiro Sérgio L. G. Antunes Márcia M. Jardim Claudia de J. F. Covas Ximena Illaramendi Ida M. Dias-Baptista Patrícia S. Rosa Sandra M. B. Dur?es Antonio G. Pacheco Marcelo Ribeiro-Alves Euzenir N. Sarno Milton O. Moraes 《PLoS neglected tropical diseases》2014,8(9)
Mycobacterium leprae infects macrophages and Schwann cells inducing a gene expression program to facilitate its replication and progression to disease. MicroRNAs (miRNAs) are key regulators of gene expression and could be involved during the infection. To address the genetic influence of miRNAs in leprosy, we enrolled 1,098 individuals and conducted a case-control analysis in order to study four miRNAs genes containing single nucleotide polymorphism (miRSNP). We tested miRSNP-125a (rs12975333 G>T), miRSNP-223 (rs34952329 *>T), miRSNP-196a-2 (rs11614913 C>T) and miRSNP-146a (rs2910164 G>C). Amongst them, miRSNP-146a was the unique gene associated with risk to leprosy per se (GC OR = 1.44, p = 0.04; CC OR = 2.18, p = 0.0091). We replicated this finding showing that the C-allele was over-transmitted (p = 0.003) using a transmission-disequilibrium test. A functional analysis revealed that live M. leprae (MOI 100∶1) was able to induce miR-146a expression in THP-1 (p<0.05). Furthermore, pure neural leprosy biopsies expressed augmented levels of that miRNA as compared to biopsy samples from neuropathies not related with leprosy (p = 0.001). Interestingly, carriers of the risk variant (C-allele) produce higher levels of mature miR-146a in nerves (p = 0.04). From skin biopsies, although we observed augmented levels of miR-146a, we were not able to correlate it with a particular clinical form or neither host genotype. MiR-146a is known to modulate TNF levels, thus we assessed TNF expression (nerve biopsies) and released by peripheral blood mononuclear cells infected with BCG Moreau. In both cases lower TNF levels correlates with subjects carrying the risk C-allele, (p = 0.0453 and p = 0.0352; respectively), which is consistent with an immunomodulatory role of this miRNA in leprosy. 相似文献
66.
67.
Adriana Gijon‐Hernandez Daniel Teliz‐Ortiz Dimas Mejia‐Sanchez Rodolfo De La Torre‐Almaraz Elizabeth Cardenas‐Soriano Carlos De Leon Antonio Mora‐Aguilera 《Journal of Phytopathology》2011,159(5):377-381
A disease in maize plants, not previously observed, appeared in 2003–2004 in Cosoleacaque, Tlalixcoyan and Paso de Ovejas counties, in the state of Veracruz, Mexico. Initial symptoms on leaves were small white‐yellow watery spots, which coalesced into dry necrotic stripes 0.3 wide and up to 8 cm long. Reddening sometimes developed on these leaves. Stems developed a rot in the crown. The flag leaf became rot and necrotic at the base, rolled inwards and dried out. Necrosis developed at the base of the corn ears and their growth was inhibited. These symptoms were initially observed in Asgrow‐7573 commercial maize plantings. A bacterium characterized by white colonies, gram negative, aerobic, rod‐shape, opaque, round colonies with entire margins on casaaminoacid peptone and glucose media was consistently isolated from diseased maize plants. On King’s Medium B, the isolates produced yellow, non‐mucoid colonies, with the majority of the strains secreting a diffusible yellow pigment into the media. The bacterium identity was confirmed by PCR amplification and sequencing of 16S and 23S genes rDNA fragments. The bacterium was identified as Burkholderia gladioli. Its pathogenicity on maize plants in Mexico is a new record. 相似文献
68.
69.
Subtropical streams harbour higher genus richness and lower abundance of insects compared to boreal streams,but scale matters 下载免费PDF全文
70.
Leonardo Lucas Carnevalli Dias Dimas Mendes Ribeiro Claudete Santa Catarina Raimundo Santos Barros Eny Iochevet Segal Floh Wagner Campos Otoni 《Plant Growth Regulation》2010,62(1):9-19
Ethylene is a plant hormone that is of fundamental importance to in vitro morphogenesis, but in many species, it has not been
thoroughly studied. Its relationship with polyamines has been studied mainly because the two classes of hormones share a common
biosynthetic precursor, S-adenosylmethionine (SAM). In order to clarify whether competition between polyamines and ethylene
influences in vitro morphogenetic responses of Passiflora cincinnata Mast., a climacteric species, different compounds were used that act on ethylene biosynthesis and action, or as ethylene
scavengers. Treatment with the ethylene inhibitor, aminoethoxyvinylglycine (AVG) caused a greater regeneration frequency in
P. cincinnata, whereas treatment with the ethylene precursor, 1-aminocyclopropane-1-carboxylic-acid (ACC) lessened regeneration frequencies.
The data suggested that levels of polyamines and ethylene are not correlated with morphogenic responses in P. cincinnata. It was ascertained that neither the absolute ethylene and polyamine levels, nor competition between the compounds, correlated
to the obtained morphogenic responses. However, sensitivity to, and signaling by, ethylene appears to play an important role
in differentiation. This study reinforces previous reports regarding the requirement of critical concentrations and temporal
regulation of ethylene levels for morphogenic responses. Temporal regulation also appeared to be a key factor in competition
between the two biosynthetic pathways, without having any effects on morphogenesis. Further studies investigating the silencing
or overexpression of genes related to ethylene perception, under the influence of polyamines in cell differentiation are extremely
important for the complete understanding of this process. 相似文献