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Effects of aluminum speciation on murine neuroblastoma cells.

Murine neuroblastoma cells behave differently in the presence of Al(acac)3 [acac = 2,4-pentanedionate; acetylacetonate] or Al(malt)3 [malt = 3-hydroxy, 2-methyl, 4-pyronate; maltolate] with respect to Al(lac)3 [lac = 2-hydroxypropionate; lactate]. Thus, a remarkable cytotoxic effect was observed in the first case; on the contrary, an evident cytostatic and neuritogenic effect was produced by aqueous Al(lac)3. The hydrolytically stable complexes Al(acac)3 and Al(malt)3 were both toxic in the concentration range of 0.10-0.30 and 0.10-0.50 mM, respectively, over 24 h. In contrast with this behavior Al(lac)3 displayed a potent cytostatic activity with induction of neurites at 0.2-10 mM. Al(OH)3 manifested biological effects comparable to those exhibited by Al(lac)3. AlPO4 was also cytostatic and led to a morphological differentiation of the neuroblastoma cells, qualitatively different from that elicited by Al(lac)3. The morphological effects induced by Al(lac)3, Al(OH)3, and AlPO4 were irreversible.

Aluminum↗

Rapid evolution of a young L1 (LINE-1) clade in recently speciated Rattus taxa.

L1 elements are retrotransposons that have been replicating and evolving in mammalian genomes since before the mammalian radiation. Rattus norvegicus shares the young L1mlvi2 clade only with its sister taxon, Rattus cf moluccarius. Here we compared the L1mlvi2 clade in these recently diverged species and found that it evolved rapidly into closely related but distinct clades: the L1mlvi2-rm clade (or subfamily), characterized here from R. cf moluccarius, and the L1mlvi2-rn clade, originally described in R. norvegicus. In addition to other differences, these clades are distinguished by a cluster of amino acid replacement substitutions in ORF I. Both rat species contain the L1mlvi2-rm clade, but the L1mlvi2-rn clade is restricted to R. norvegicus. Therefore, the L1mlvi2-rm clade arose prior to the divergence of R. norvegicus and R. cf moluccarius, and the L1mlvi2-rn clade amplified after their divergence. The total number of L1mlvi2-rm elements in R. cf moluccarius is about the same as the sum of the L1mlvi2-rm and L1mlvi2-rn elements in R. norvegicus. The possibility that L1 amplification is in some way limited so that the two clades compete for replicative supremacy as well as the implications of the other distinguishing characteristic of the L1mlvi2-rn and L1mlvi2-rm clades are discussed.

Amino Acid Sequence↗