Enzymatic Modification of Palmarosa Essential Oil: Chemical Analysis and Olfactory Evaluation of Acylated Products

We have developed an enzymatic protocol to modify the composition of palmarosa essential oil by acylation of its alcohol components by three different acyl donors at various rates. The resulting modified products were characterized by qualitative and quantitative analyses by gas chromatography, and their olfactory properties were evaluated by professional perfumers. We showed that our protocol resulted in two types of modifications of the olfactory properties. The first and most obvious effect observed was the decrease of the alcohol content, with the concomitant increase of the corresponding esters, along with their fruity notes (pear, most notably). The second and less obvious effect was the expression of notes from minor components ((E)‐β‐ocimene, linalool, β‐caryophyllene, and farnesene), originally masked by the sweet‐floral‐rose odor of geraniol, present in 70% in the palmarosa essential oil used, and emergence of citrus, green, spicy and clove characters in the modified products. This methodology might be considered in the future as a sustainable route to new natural ingredients for the perfumer.     

Developmental instability of vascular plants in contrasting microclimates at ‘Evolution Canyon’

Rocellaria dubia bores into subtidal rocks of karsted limestone in the Adriatic Sea and elsewhere. It also bores into the shells of various bivalve species. The mechanism of boring has hitherto been debated, but examination of occupied shells suggest that this is achieved by mechanical (the shell) abrasion and chemical etching using secretions produced from glands in the anterior mantle. Fast‐growing bivalves such as Ostrea edulis and Pinna nobilis carry heavy R. dubia burdens, and encapsulate the borer in secreted calluses. Slow‐growing bivalves such as the burrowing Venus verrucosa and Glycymeris violacescens carry low R. dubia burdens, are less able to encapsulate the borers, and probably incur enhanced mortalities as a result. Individuals of R. dubia removed from their limestone boreholes re‐secreted adventitious tubes around their siphons, probably from glands in the posterior mantle. The lifestyle of R. dubia is now better understood, and its ability to bore bivalve shells in particular suggests how the more advanced tropical gastrochaenids Cucurbitula and Eufistulana have evolved from initial (as juveniles) bivalve shell borers into occupants of adventitious crypts and tubes, respectively. It is further argued that the Gastrochaenidae show convergent similarities with the similar crypt‐ and tube‐building representatives of the Clavagelloidea. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 786–804.     

New evidence for parallel evolution of colour patterns in Malagasy poison frogs (Mantella)

Malagasy poison frogs of the genus Mantella are diurnal and toxic amphibians of highly variable and largely aposematic coloration. Previous studies provided evidence for several instances of homoplastic colour evolution in this genus but were unable to sufficiently resolve relationships among major species groups or to clarify the phylogenetic position of several crucial taxa. Here, we provide cytochrome b data for 143 individuals of three species in the Mantella madagascariensis group, including four newly discovered populations. Three of these new populations are characterized by highly variable coloration and patterns but showed no conspicuous increase of haplotype diversity which would be expected under a scenario of secondary hybridization or admixture of chromatically uniform populations. Several populations of these variable forms and of M. crocea were geographically interspersed between the distribution areas of Mantella aurantiaca and Mantella milotympanum. This provides further support for the hypothesis that the largely similar uniformly orange colour of the last two species evolved in parallel. Phylogenies based on over 2000 bp of two nuclear genes (Rag-1 and Rag-2) identified reliably a clade of the Mantella betsileo and Mantella laevigata groups as sister lineage to the M. madagascariensis group, but did not support species within the latter group as monophyletic. The evolutionary history of these frogs might have been characterized by fast and recurrent evolution of colour patterns, possibly triggered by strong selection pressures and mimicry effects, being too complex to be represented by simple bifurcating models of phylogenetic reconstruction.     

Factors controlling upper Jurassic ammonite assemblages in north-central Mexico

Lower Kimmeridgian to Lower Tithonian (Upper Jurassic) sections studied at Sierra de Palotes (Durango) and Sierra de Catorce (San Luis Potosí), Mexico, show low-energy deposits in which the composition of fossil macroinvertebrate assemblages, including megabenthos, reflects biostratinomic control. Monotonous siltstones provide continuous records of ammonite assemblages and reflect dominant deposition of shells in living areas; meanwhile, discontinues records were forced by episodic post-mortem transportation of shells, which was especially accentuated under storm influence. Rhythmic marly-silty limestones and marls illustrate a fossil record probably determined by minor transgressive-regressive pulses. The major changes in lithofacies are reflected by condensed silty and phosphatic mudstones deposited during significant floodings affecting areas under dominant terrigenous sedimentation. These changes determined more or less significant variations in the composition of fossil assemblages according to their relation to changing ecological conditions. However, shifting ecospaces exhibit no direct relationship to changes in lithofacies. Post-mortem transportation, operating in relation to both marine floodings and changes in the pattern of upper-water currents, was the main biostratinomic factor affecting the areal distribution of ammonite populations. Shell transportation and sedimentation rate controlled preservation and ultimately influenced diversity in recorded ammonite assemblages. The post-mortem behaviour (interpreted from shell structure and preservation), and therefore distribution, of ammonite shells points to shallow-water environments during the Kimmeridgian - Early Tithonian in areas (such as SE Durango and San Luís Potosí) close to the changing boundary between dominant carbonate and terrigenous sedimentation. No reworking affecting ammonite biostratigraphy has been identified in the sections studied.     

Multiple Pleistocene refugia and Holocene range expansion of an abundant southwestern American desert plant species (Melampodium leucanthum,Asteraceae)

Pleistocene climatic fluctuations had major impacts on desert biota in southwestern North America. During cooler and wetter periods, drought‐adapted species were isolated into refugia, in contrast to expansion of their ranges during the massive aridification in the Holocene. Here, we use Melampodium leucanthum (Asteraceae), a species of the North American desert and semi‐desert regions, to investigate the impact of major aridification in southwestern North America on phylogeography and evolution in a widespread and abundant drought‐adapted plant species. The evidence for three separate Pleistocene refugia at different time levels suggests that this species responded to the Quaternary climatic oscillations in a cyclic manner. In the Holocene, once differentiated lineages came into secondary contact and intermixed, but these range expansions did not follow the eastwardly progressing aridification, but instead occurred independently out of separate Pleistocene refugia. As found in other desert biota, the Continental Divide has acted as a major migration barrier for M. leucanthum since the Pleistocene. Despite being geographically restricted to the eastern part of the species’ distribution, autotetraploids in M. leucanthum originated multiple times and do not form a genetically cohesive group.     

Raising Awareness of Amphibian Chytridiomycosis will not Alienate Ecotourists Visiting Madagascar

Chytridiomycosis (Bd) is contributing to amphibian extinctions worldwide but has so far not been detected in Madagascar. The high likelihood for Bd to spread to the island and efface this amphibian diversity and endemism hotspot requires respective conservation policies to be developed. Bd could be introduced by the large number of tourists that visit protected areas; therefore, increasing awareness among tourists and encouraging them to participate in safety measures should be a priority conservation action. However, concerns have been raised that tourists would not be able to distinguish between an amphibian disease harmless to humans and emerging diseases that would imply a danger for human health, invoking a negative image of Madagascar as an ecotourism destination. We evaluated whether informing tourists about this infectious animal disease would cause health scare and diminish trip satisfaction. Based on 659 respondents we found that most ecotourists favored to be informed about Bd and were proactive about participating in prevention measures, refuting previous concerns.     

国际植物学墨尔本大会上命名法规的变化

2011年7月在第18届国际植物学大会命名法分会上通过了命名法规的一系列重大改动,并在全体大会上得到了接受批准。文中就命名法规的变化进行了简单概述,同时也讨论了这些变化的意义,特别是对菌物研究的意义,以期引起广大研究人员的关注。