Induction and Characterization of Laccase in the Ligninolytic Fungus Pleurotus eryngii

Two protein bands with laccase activity were found after PAGE of culture liquid or mycelium extract of Pleurotus eryngii, grown on glucose–ammonium tartrate–yeast extract medium with and without inducers. A major and a minor laccase band were observed in the basal medium. The intensity of the major band (laccase I) did not change after the addition of inducers. However, the minor band (laccase II), characterized by higher electrophoretic mobility, was strongly induced by wheat–straw alkalilignin and vanillic and veratric acids. Laccase activity in the basal medium had an optimum pH of 4.5 and was stable from pH 3 to 10 during 24 h at room temperature. This enzyme had wide substrate specificity on hydroquinones, methoxy-substituted monophenols, and aromatic amines. In general, laccase activity was found only with compounds having a redox potential lower than 0.5 mV. The highest activity was obtained with methoxy- and methyl-substituted p-hydroquinones and aromatic diamines. Some activity also occurred with the aliphatic compound 3,5-cyclohexadiene-1,2-diol. Received: 22 April 1996 / Accepted: 29 June 1996     

Alien plants of coastal dune habitats in southern Spain

Alien plants from psammophilous ecosystems have been studied in southern Spain. Sixteen sites, which are included in the Andalusian Network of Protected Spaces, have been chosen along 1100 km of Andalusian coasts in order to verify the degree of abundance and influence of these species on different communities. Out of the 26 localized species, the increase of some invasive plants, such as Arctotheca calendula, Agave americana, A. sisalana, Cortaderia selloana, Lantana camara and Opuntia dillenii, affects the conservation of some natural coastal ecosystems.     

Spatial distribution of fine root biomass in a remnant Eucalyptus tereticornis woodland in Eastern Australia

Plant Ecology - In forests, the majority of fine roots are located within the upper soil horizons, and fine root biomass decreases with depth. We evaluated spatial patterns in the distribution of...     

Physiographic and climatic events in the Chihuahuan Desert lead to the speciation and distinct demographic patterns of two sister Sceloporus lizards

The biogeographic history of the Chihuahuan Desert is known to be complex, and there is evidence of the effects of physiographic and climatic events in species diversification and demographic population changes in many taxa. Here, using DNA sequence data, we studied the influence of the physiographic and climatic events that occurred in the Chihuahuan Desert during the Pliocene–Pleistocene transition on the speciation and evolutionary history of the sister lizard species Sceloporus cyanostictus and S. gadsdeni. First, based on mtDNA and nDNA sequences, we estimated the divergence times of the sister species. Then, based on mtDNA sequences, we investigated the demographic history of both species within a phylogeographic framework. The divergence time was inferred to be 1.48 Mya, date that corresponds to the existence of a large lake in the Mapimian subprovince, between the current geographic locations of S. cyanostictus and S. gadsdeni. This lake could have acted as a barrier, leading to the speciation of both species. For the demographic history of the two species, we identified two distinct patterns: the population expansion of S. gadsdeni within the Last Glacial Maximum and the potential population decline of S. cyanostictus. Our results can be used as a guide for the study of other aspects that could be critical to developing conservation actions that ensure the survival of not only S. gadsdeni and S. cyanostictus, but also other co‐occurring lizard species.     

From dusk till dawn: camera traps reveal the diel patterns of flower feeding by hawkmoths

1. Diel rhythms of foraging activity by animal flower visitors can reflect niche partitioning and are considered an important component of selection on floral traits. However, it has been notoriously difficult to obtain objective information on the patterns of flower visitation by crepuscular and nocturnal insects. 2. Motion-activated cameras were used for field-based studies of hawkmoth foraging behaviour on six African plant species. 3. The results showed that short-tongued hawkmoth species forage mainly around dusk and then sporadically throughout the night, whereas long-tongued hawkmoth species feed consistently throughout the night, with a peak shortly before midnight. 4. These results provide the first quantitative estimates of diel patterns of interactions between multiple hawkmoth and plant species and, when combined with qualitative reports from other studies, suggest that differences in diel activity between the two main hawkmoth functional groups (short- and long-tongued) are consistent across the Old and New Worlds.