Large numbers of rotifer eggs from sediment resting egg banks may hatch simultaneously under appropriate conditions; therefore, natural populations are likely to be multiclonal in a growing season. A recent field inve...Large numbers of rotifer eggs from sediment resting egg banks may hatch simultaneously under appropriate conditions; therefore, natural populations are likely to be multiclonal in a growing season. A recent field investigation showed that subordinate and ephemeral clones were able to establish populations in an environment with several strongly dominant clone populations. However, it was not clear how the subordinate populations maintained their growth under these conditions where the crowding signal would induce high levels of sexual reproduction in the dominant clone populations. In the present study, we conducted a continuous passage to 60 generations for new populations at three different temperatures （15~C, 25~C, and 35~C）. These populations emerged from resting eggs produced by a clone population. At the first, 30th, and 60th generations, the populations were sampled and fitness was assayed using the life-table method. We found a significant short-term fitness advantage for populations newly emerged from resting eggs produced by a clone population of the rotifer Brachionus calycifiorus, followed by a significant decrease in relative fitness with long-term continuous passage. Our results suggested that the early short- term fitness advantage was important for later-hatched and subordinate clone populations in an environment with multiple sympatric clones. The early short-term fitness might also promote the coexistence of sympatric clones because it could help to offset the cost of early sexual reproduction.展开更多
A novel triple lines lateral-flow assay （LFA） with enhanced sensitivity for the detection of Leishmania infantum DNA in dog blood samples was designed and successfully applied. The enhanced LFA methodology takes adv...A novel triple lines lateral-flow assay （LFA） with enhanced sensitivity for the detection of Leishmania infantum DNA in dog blood samples was designed and successfully applied. The enhanced LFA methodology takes advantage of the gold nanoparticle tags （AuNPs） conjugated to polyclonal secondary antibodies, which recognize anti-FITC antibodies. The polyclonal nature of the secondary antibodies allows for multiple binding to primary antibodies, leading to enhanced AuNP plasmonics signal. Furthermore, endogenous control consisting of the amplified dog 18S rRNA gene was introduced to avoid false negatives. Using this strategy, 0.038 spiked Leishmania parasites per DNA amplification reaction （1 parasite/100 μL of DNA sample） were detected. Detection limit of LFA was found to be lower than that of the conventional techniques. In summary, our novel LFA design is a universal and simple sensing altemative that can be extended to several other biosensing scenarios.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.30970349,41206110)
文摘Large numbers of rotifer eggs from sediment resting egg banks may hatch simultaneously under appropriate conditions; therefore, natural populations are likely to be multiclonal in a growing season. A recent field investigation showed that subordinate and ephemeral clones were able to establish populations in an environment with several strongly dominant clone populations. However, it was not clear how the subordinate populations maintained their growth under these conditions where the crowding signal would induce high levels of sexual reproduction in the dominant clone populations. In the present study, we conducted a continuous passage to 60 generations for new populations at three different temperatures （15~C, 25~C, and 35~C）. These populations emerged from resting eggs produced by a clone population. At the first, 30th, and 60th generations, the populations were sampled and fitness was assayed using the life-table method. We found a significant short-term fitness advantage for populations newly emerged from resting eggs produced by a clone population of the rotifer Brachionus calycifiorus, followed by a significant decrease in relative fitness with long-term continuous passage. Our results suggested that the early short- term fitness advantage was important for later-hatched and subordinate clone populations in an environment with multiple sympatric clones. The early short-term fitness might also promote the coexistence of sympatric clones because it could help to offset the cost of early sexual reproduction.
文摘A novel triple lines lateral-flow assay （LFA） with enhanced sensitivity for the detection of Leishmania infantum DNA in dog blood samples was designed and successfully applied. The enhanced LFA methodology takes advantage of the gold nanoparticle tags （AuNPs） conjugated to polyclonal secondary antibodies, which recognize anti-FITC antibodies. The polyclonal nature of the secondary antibodies allows for multiple binding to primary antibodies, leading to enhanced AuNP plasmonics signal. Furthermore, endogenous control consisting of the amplified dog 18S rRNA gene was introduced to avoid false negatives. Using this strategy, 0.038 spiked Leishmania parasites per DNA amplification reaction （1 parasite/100 μL of DNA sample） were detected. Detection limit of LFA was found to be lower than that of the conventional techniques. In summary, our novel LFA design is a universal and simple sensing altemative that can be extended to several other biosensing scenarios.
