Enhanced Multiplication of Intracellular (Amastigote) Stages of Trypanosoma cruzi In Vitro1

Amastigotes of different strains of Trypanosoma cruzi responded to stimulation with concanavalin A in an axenic medium by increased DNA synthesis and cell multiplication. These effects were inhibited by α-methyl mannoside. Other mitogens, i.e. phytohemagglutinin P, castor bean ricin Type II isolated from Ricinus communis, and a bacterial lipopolysaccharide, had no effect on amastigote growth. Amastigote stimulation by concanavlin A lends itself to studies on the biochemistry and cell cycle of this human pathogen.     

Cryptic diversity within the Moroccan endemic day geckos Quedenfeldtia (Squamata: Gekkonidae): a multidisciplinary approach using genetic,morphological and ecological data

Quedenfeldtia (Boettger, 1883) is a genus of diurnal geckos, endemic to the Atlas Mountains in Morocco, with two species being recognized: Quedenfeldtia moerens and Quedenfeldtia trachyblepharus. Quedenfeldtia moerens is found across a wide variety of habitats, from sea level to 3000 m a.s.l., whereas Q. trachyblepharus occupies exclusively high mountain regions reaching up to 4000 m a.s.l. This differentiation, offers an interesting model for study biogeographical patterns and evolutionary scenarios in a North African endemic. Analysis of two mitochondrial (12S rRNA and ND4) and four nuclear (ACM4, MC1R, PDC, and Rag1) DNA markers revealed high genetic variation, consistent with other recent phylogeographical studies, and with the two currently described species. However, within each species, a subdivision into two groups with geographical consistence was found. Multivariate morphological analyses confirmed the existence of two main phenotypes, whereas ecological niche modelling identified various environmental variables associated with the distribution of each species, and helped to predict occurrences outside the confirmed ranges. The results obtained in the present study indicate the possible existence of additional ‘cryptic’ species within this genus, a condition found in many North African reptiles, and particularly common in geckos. In general, North African montane fauna appears to reflect the occurrence of diverse palaeoendemics, as seen in Central Africa Mountain systems, rather than the pattern of recent postglacial recolonization observed in Europe. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

From forest to plantation? Obscure articles reveal alternative host plants for the coffee berry borer,Hypothenemus hampei (Coleoptera: Curculionidae)

The coffee berry borer, Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae), is the most devastating insect pest of coffee throughout the world. The insect is endemic to Africa but can now be found throughout nearly all coffee‐producing countries. One area of basic biology of the insect that remains unresolved is that of its alternative host plants, i.e. which fruits of plants, other than coffee, can the insect survive and reproduce in. An in‐depth survey of the literature revealed an article by Schedl listing 21 genera in 13 families in which the insect was collected, mainly in the Democratic Republic of Congo. This overlooked reference, together with information provided in other early articles, suggests that H. hampei is polyphagous, and could provide, if confirmed in the field, critical information on the evolution of this insect's diet, ecology and host range. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??.     

A semimechanistic model predicting the growth and production of the bioenergy crop Miscanthus×giganteus: description, parameterization and validation

Biomass based bioenergy is promoted as a major sustainable energy source which can simultaneously decrease net greenhouse gas emissions. Miscanthus × giganteus ( M. × giganteus ), a C₄ perennial grass with high nitrogen, water, and light use efficiencies, is regarded as a promising energy crop for biomass production. Mathematical models which can accurately predict M. × giganteus biomass production potential under different conditions are critical to evaluate the feasibility of its production in different environments. Although previous models based on light-conversion efficiency have been shown to provide good predictions of yield, they cannot easily be used in assessing the value of physiological trait improvement or ecosystem processes. Here, we described in detail the physical and physiological processes of a previously published generic mechanistic eco-physiological model, WIMOVAC, adapted and parameterized for M. × giganteus . Parameterized for one location in England, the model was able to realistically predict daily field diurnal photosynthesis and seasonal biomass at a range of other sites from European studies. The model provides a framework that will allow incorporation of further mechanistic information as it is developed for this new crop.     

Phylogenetic analysis of the Mexican freshwater crabs of the tribe Pseudothelphusini (Decapoda: Brachyura: Pseudothelphusidae)

The Mexican pseudothelphusid crabs are classified in one subfamily, three tribes, and 13 genera. Up to now, 56 species have been recognized, distributed in a strictly Neotropical pattern, with some of them reaching the state of Sonora on the western slope of Mexico. The tribe Pseudothelphusini is the most diverse, with five genera and 35 species, all of them endemic to Mexico: the two most species‐rich genera are Pseudothelphusa, with 23 species, and Tehuana, with eight species; Epithelphusa includes two species, whereas Disparithelphusa and Smalleyus are monotypic. The Pseudothelphusini lack an updated systematic revision, which could serve as a framework to analyse the monophyletic origin of the group, to clarify the relationships among genera and species, as well as to resolve the taxonomic status of various species complexes. In the present study, an exhaustive morphological revision was conducted using somatic and sexual characters. A phylogenetic analysis was performed using 77 characters and 183 character states, taken from 41 species. Ten trees of the same length were obtained using PAUP 4.0 through a heuristic search. The results show that the tribe as it is actually known constitutes a paraphyletic group, in which the species of Epithelphusa and Pseudothelphusa puntarenas are excluded from the internal group. According to the obtained results, the tribe Pseudothelphusini s.s. includes five genera: Smalleyus, Pseudothelphusa, Tehuana, and two new ones to accommodate Pseudothelphusa galloi and Pseudothelphusa sulcifrons, respectively. This new arrangement considers the provisional suppression of the genus Disparithelphusa, which remained as another species of Pseudothelphusa throughout the cladistic analysis. The phylogenetic results show a strong congruence with the distribution of the species, in several cases grouping species that form morphological clines along a geographical gradient. The previously proposed southern origin of the tribe Pseudothelphusini gains support with the results obtained. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 457–481     

Demography of the clonal palm Geonoma brevispatha in a Neotropical swamp forest

Abstract We expected that in clonal plants with the phalanx growth form, prereproductive ramets function as a meristem bank that helps buffer ramet demography against environmental fluctuations. Specifically, we evaluated four expectations for the forest understorey clonal palm Geonoma brevispatha in a swamp forest in south‐eastern Brazil. Our expectations were are follows: (i) the vital rates of prereproductive ramets are more responsive to genet‐related characteristics (genet size, distance and size of the nearest genet neighbour, and reproductive ramet survivorship) than to environmental variables (canopy openness, basal area of small trees, flooding, and distance and size of the nearest large tree neighbour), whose effects are expected to affect ramet dynamics indirectly through physiological integration; (ii) the progress of prereproductive ramets to later stages is dependent on the death of reproductive ramets; (iii) the population dynamics of G. brevispatha is resistant to significant interannual changes in the vital rates of ramets, (i.e. the occurrence of good and bad years); and (iv) there are large negative covariances among demographic transitions within a given year, as well as between years, reflecting the flexibility of G. brevispatha to adjust to environmental variability. Expectations 1, 2 and 4 were confirmed, while expectation 3 was only partially confirmed. Matrix models predicted that the growth rate of the overall ramet population was significantly greater than unity in the first study year, but it was significantly smaller than 1.0 in the second study year. Ramet population growth rates at the level of individual genets were greater than unity in the majority of genets in the first year, but in the second year genets with growth rates smaller than unity prevailed. Ramet population dynamics seems to be resistant to the succession of good and bad years; in effect, the presence of a meristem bank of ramets helps stabilize λ.     

LEISHMANIASIS ENTOMOLOGICAL FIELD STUDIES: ETHICAL ISSUES

Occupational health remains neglected in developing countries because of competing social, economic and political challenges. Ethical issues in the workplace related to the hazards and risks of becoming infected by Leishmania (Leishmania) mexicana , through the bite of naturally infected sand flies, is another area of concern that has been neglected as well. We report here the results of reviewing two entomological field studies carried out in our research center from 2003 to 2006. Eight students from our School of Biology were invited to catch sand flies. A total of six of the eight (75%) developed a typical clinical picture of Localized Cutaneous Leishmaniasis (LCL) caused by L. (L.) mexicana . In this article we identify the ethical issues related to these kinds of studies and propose some guidelines for conducting them.