The cactus Mammillaria gracillis Pfeiff. was propagated in vitro on Murashige and Skoog (MS) medium without any growth regulators. At the bases of some plants abundant callus masses developed. Lower agar and higher MS salt concentrations stimulated callus pro­ duction. In the culture, morphologically normal and hyperhydric shoots were regenerated. The growth of crown-gall tumour was induced on ...

The endemic Mexican cactus, Mammillaria pectinifera, shows low dispersal capabilities and isolated populations within the highly dissected landscape of Tehuacán Valley. These characteristics can restrict gene flow and act upon the genetic divergence and speciation in arid plants. We conducted a phylogeographic study to determine if the origin, current distribution, and genetic structure of M. p...

This investigation analyzed the Zn-bioaccumulation kinetics in the abalone Haliotis diÕersicolor supertexta and in the red alga Gracilaria tenuistipitata var. liui for assessing bioconcentration and biomagnification in an aquacultural system. Laboratory exposure experiments estimated Ž . uptake and depuration rate constants i.e., k and k , respectively of H. diÕersicolor supertexta 1 2 Ž . via ...

This study is about four cacti species in the state of Chihuahua, (Coryphantha macromeris, Mammillaria lasiacantha, Echinocereus dasyacanthus and Ferocactus wislizenii). Geographic distribution was inferred with MaxEnt. Projection was estimated under three scenarios simulated from IPCC (A2, B1 and A1B) and four periods (2000, 2020, 2050 and 2080) with 19 climatic variables. MaxEnt projects a sp...

*WERNICKE first published an account of the condition in 1881. He based his account upon three cases and described the condition as one of acute superior haemorrhagic polioencephalitis. Two of his cases were due to chronic alcoholism and the third to sulphuric acid poisoning. All the cases showed minute haemorrhagic foci situated in the walls of the third ventricle, the grey matter around the a...