Neuroprotective activity of triterpenoid saponins from Platycodi radix against glutamate-induced toxicity in primary cultured rat cortical cells. (9/28)

During our investigation of the neuroprotective activity of Platycodi radix we found that an aqueous extract of this folk medicine exhibited significant protection against glutamate-induced toxicity in primary cultured rat cortical cells. In order to clarify the neuroprotective mechanism(s) of this observed effect, activity-guided isolation was performed to seek and identify active fractions and components. By such fractionation, four known triterpene saponin compounds--platycodins A, C and D and deapioplatycodin D--were isolated from the n-butanol fraction. Among these four compounds, platycodin A exhibited significant neuroprotective activities against glutamate-induced toxicity, exhibiting cell viability of about 50%, at concentrations ranging from 0.1 microM to 10 microM. Therefore, the neuroprotective effect of Platycodi radix might be due to the inhibition of glutamate-induced toxicity by the saponin compounds it contains.  (+info)

Transgenerational plasticity is adaptive in the wild. (10/28)

Plants exhibit adaptive responses to light, but it is not known whether parental plants transmit environmental cues that elicit adaptive responses in offspring. We show that offspring life history (annual versus biennial) is influenced by the maternal light environment (understory versus light gap). This transgenerational plasticity is adaptive when offspring are grown in their maternal light environment, where seeds typically disperse. Projections of population growth show that plants that are appropriately cued for their light environment through maternal effects have 3.4 times greater fitness than otherwise. Transgenerational plasticity has evolved in response to natural variation in light and provides a flexible mechanism by which sedentary organisms cope with heterogeneous environments.  (+info)

Origin, adaptive radiation and diversification of the Hawaiian lobeliads (Asterales: Campanulaceae). (11/28)

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A fast algorithm for the multiple genome rearrangement problem with weighted reversals and transpositions. (12/28)

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Going to great lengths: selection for long corolla tubes in an extremely specialized bat-flower mutualism. (13/28)

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Wickerhamomyces queroliae sp. nov. and Candida jalapaonensis sp. nov., two yeast species isolated from Cerrado ecosystem in North Brazil. (14/28)

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Isolated populations of a rare alpine plant show high genetic diversity and considerable population differentiation. (15/28)

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Have giant lobelias evolved several times independently? Life form shifts and historical biogeography of the cosmopolitan and highly diverse subfamily Lobelioideae (Campanulaceae). (16/28)

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