Adipogenic genes on induction and stabilization of commitment to adipose conversion

Most late events of adipose conversion are known, but those early events that lead to cell commitment, and important aspects of its mechanism remain unknown. We recently described that, in the absence of any other adipogenic factor, 4 h incubation with staurosporine promotes commitment of 3T3-F442A cells to adipogenesis. This commitment consists of two stages; a first stage of 4 h induction by staurosporine, and, in the absence of this drug, a second stage of stabilization which becomes completed after 40-48 h from staurosporine treatment. Here, we demonstrate that pparg2 gene is expressed early after induction stage but before commitment is stabilized, whereas cebpa is highly expressed during the last part of stabilization stage. A decrease of dlk1 expression, whose down-regulation is indispensable for adipogenesis, began to take place between 24 and 48 h of St-Dex incubation started, reaching the lowest levels well into the end of stabilization stage.     

DupTree: a program for large-scale phylogenetic analyses using gene tree parsimony

DupTree is a new software program for inferring rooted species trees from collections of gene trees using the gene tree parsimony approach. The program implements a novel algorithm that significantly improves upon the run time of standard search heuristics for gene tree parsimony, and enables the first truly genome-scale phylogenetic analyses. In addition, DupTree allows users to examine alternate rootings and to weight the reconciliation costs for gene trees. DupTree is an open source project written in C++. Availability: DupTree for Mac OS X, Windows, and Linux along with a sample dataset and an on-line manual are available at http://genome.cs.iastate.edu/CBL/DupTree     

A model for small‐scale seed bank and standing vegetation connection along time

Since inter‐annual climatic variability influences composition and structure of seed bank and extant vegetation, it is expected that it also affects the relationship between both compartments at small scales along time. We hypothesize that seed bank and aboveground vegetation are closely and sequentially linked at small spatial and time scales. We conducted a field spatially explicit investigation to explore the spatial and temporal relationship between both compartments. Abundance, composition and spatial structure at different small‐scales of seed bank and aboveground vegetation were analysed through 100 permanent plots during two consecutive (dry and wet) periods of growth. Following a conceptual transition path model, we analysed changes in correlation values in composition and spatial aggregation between both compartments along time including seasonal variations of seed bank. Shape of spatial structures were evaluated using partial Mantel correlograms. Annuals and perennials guilds were studied separately. During the wet year, annuals increased their aerial spatial aggregation and cover, whereas the opposite happened for perennials. Density and spatial aggregation of the seed bank increased for both guilds in the two seasons following the rain period, especially in annuals. The clumped structure of the transient seed bank is a consequence of the addition of spatial structure of extant vegetation and the persistent seed bank. Expression of the persistent seed bank is much lower during the dry period for the annual guild. In spite of the strong yearly variability, the community maintained a highly structured spatiotemporal pattern. The mechanisms promoting this stability differed for annual and perennial guilds. Temporal persistence in perennials relied mainly in established plants longevity, whereas annual guild persistence depended solely on seed bank. This tight structure was coherent with the existence of successional dynamics in the community, although persistent seed bank could moderate the pace. Longer term studies of seed bank–standing vegetation dynamics are required to fully understand this process.     

Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropods

Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods.     

Successful elimination of a lethal wildlife infectious disease in nature

Methods to mitigate the impacts of emerging infectious diseases affecting wildlife are urgently needed to combat loss of biodiversity. However, the successful mitigation of wildlife pathogens in situ has rarely occurred. Indeed, most strategies for combating wildlife diseases remain theoretical, despite the wealth of information available for combating infections in livestock and crops. Here, we report the outcome of a 5-year effort to eliminate infection with Batrachochytrium dendrobatidis affecting an island system with a single amphibian host. Our initial efforts to eliminate infection in the larval reservoir using a direct application of an antifungal were successful ex situ but infection returned to previous levels when tadpoles with cleared infections were returned to their natal sites. We subsequently combined antifungal treatment of tadpoles with environmental chemical disinfection. Infection at four of the five pools where infection had previously been recorded was eradicated, and remained so for 2 years post-application.     

Mutualism with plants drives primate diversification

Understanding the origin of diversity is a fundamental problem in biology. Evolutionary diversification has been intensely explored during the last years due to the development of molecular tools and the comparative method. However, most studies are conducted using only information from extant species. This approach probably leads to misleading conclusions, especially because of inaccuracy in the estimation of extinction rates. It is critical to integrate the information generated by extant organisms with the information obtained from the fossil record. Unfortunately, this integrative approach has been seldom performed, and thus, our understanding of the factors fueling diversification is still deficient. Ecological interactions are a main factor shaping evolutionary diversification by influencing speciation and extinction rates. Most attention has focused on the effect of antagonistic interactions on evolutionary diversification. In contrast, the role of mutualistic interactions in shaping diversification has been much less explored. In this study, by combining phylogenetic, neontological, and paleontological information, we show that a facultative mutualistic plant-animal interaction emerging from frugivory and seed dispersal has most likely contributed to the diversification of our own lineage, the primates. We compiled diet and seed dispersal ability in 381 extant and 556 extinct primates. Using well-established molecular phylogenies, we demonstrated that mutualistic extant primates had higher speciation rates, lower extinction rates, and thereby higher diversification rates than nonmutualistic ones. Similarly, mutualistic fossil primates had higher geological durations and smaller per capita rates of extinction than nonmutualistic ones. As a mechanism underlying this pattern, we found that mutualistic extinct and extant primates have significantly larger geographic ranges, which promotes diversification by hampering extinction and increasing geographic speciation. All these outcomes together strongly suggest that the establishment of a facultative mutualism with plants has greatly benefited primate evolution and fueled its taxonomic diversification.     

Combining two teaching techniques for young children on Aedes aegypti control: effects on entomological indices in western Mexico

A study of the effect of educating four- to six-year-old children in mosquito control was recently conducted in a city in the state of Jalisco, western Mexico. Four neighborhood districts were selected. Children attending one kindergarten in each of two experimental districts were taught mosquito control with a video from the American Mosquito Control Association (AMCA), joined to the use of the AMCA Touch Table Technique. The entomological indices monitored in the study decreased significantly (P<0.05) in houses in the experimental districts, apparently because parents acted on the comments and suggestions of the children and eliminated or monitored containers used as oviposition sites by mosquitoes. Based on these results, combining both techniques for teaching children mosquito control is a potentially useful tool for control efforts in Mexico and other places in Latin America.     

ITS 2 sequences heterogeneity in Phlebotomus sergenti and Phlebotomus similis (Diptera,Psychodidae): possible consequences in their ability to transmit Leishmania tropica

An intraspecific study on Phlebotomus sergenti, the main and only proven vector of Leishmania tropica among the members of the subgenus Paraphlebotomus was performed. The internal transcribed spacer 2 (ITS2) sequences of 12 populations from 10 countries (Cyprus, Egypt, Italy, Lebanon, Morocco, Pakistan, Portugal, Spain, Syria, and Turkey) were compared. Samples also included three species closely related to P. sergenti: Phlebotomus similis (three populations from Greece and Malta), Phlebotomus jacusieli and Phlebotomus kazeruni. Our results confirm the validity of the taxa morphologically characterised, and imply the revision of their distribution areas, which are explained through biogeographical events. At the Miocene time, a migration route, north of the Paratethys sea would have been followed by P. similis to colonise the north of the Caucasus, Crimea, Balkans including Greece and its islands, and western Turkey. Phlebotomus sergenti would have followed an Asiatic dispersion as well as a western migration route south of the Tethys sea to colonise North Africa and western Europe. This hypothesis seems to be well supported by high degree of variation observed in the present study, which is not related to colonisation or to intra-populational variation. Two groups can be individualised, one oriental and one western in connection with ecology, host preferences and distribution of L. tropica. We hypothesise that they could be correlated with differences in vectorial capacities.