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Abstract.--A large-scale monitoring program associated with the establishment of a marine protected area network in southern California provided an opportunity to observe and document unique or rare species across the [...]

The human brain is unusually large. It has tripled in size from Australopithecines to modern humans.sup.1 and has become almost six times larger than expected for a placental mammal of human size.sup.2. Brains incur high metabolic costs.sup.3 and accordingly a long-standing question is why the large human brain has evolved.sup.4. The leading hypotheses propose benefits of improved cognition for overcoming ecological.sup.5-7, social.sup.8-10 or cultural.sup.11-14 challenges. However, these hypotheses are typically assessed using correlative analyses, and establishing causes for brain-size evolution remains difficult.sup.15,16. Here we introduce a metabolic approach that enables causal assessment of social hypotheses for brain-size evolution. Our approach yields quantitative predictions for brain and body size from formalized social hypotheses given empirical estimates of the metabolic costs of the brain. Our model predicts the evolution of adult Homo sapiens-sized brains and bodies when individuals face a combination of 60% ecological, 30% cooperative and 10% between-group competitive challenges, and suggests that between-individual competition has been unimportant for driving human brain-size evolution. Moreover, our model indicates that brain expansion in Homo was driven by ecological rather than social challenges, and was perhaps strongly promoted by culture. Our metabolic approach thus enables causal assessments that refine, refute and unify hypotheses of brain-size evolution.Using estimates of metabolic costs of the brain and body, mathematical predictions suggest that the evolution of adult Homo sapiens-sized brains and bodies is driven by ecological rather than social challenges and is perhaps strongly promoted by culture., Author(s): Mauricio González-Forero [sup.1] , Andy Gardner [sup.1] Author Affiliations:(1) School of Biology, University of St Andrews, St Andrews, UKMain The leading hypotheses for the evolution of brain size make [...]

ABSTRACT Background: Traditionally, molecular docking is primarily employed to screen pure compounds; the top-ranking chemicals are subsequently selected for experimental validation. Unlike synthetic chemicals, most natural products are commercially unavailable. [...]

Several studies have demonstrated the analgesic and anti-inflammatory effects of fruit and seed extracts from Pterodon emarginatus Vogel (Fabaceae). The objective of this study was to evaluate the antinociceptive activity of the hydroethanolic extract of P. emarginatus leaves in mice and characterize its chemical composition using HPLC coupled to UV-vis diode array detection and mass spectrometry with electrospray ionization. Our results showed that the doses of 500 and 1000 mg/kg produced an antinociceptive effect, as observed in the hot plate test and writhing induced by acetic acid. The chromatographic profile and spectral mass data suggest the presence of di-C-glycosylflavones (e.g., vicenin-2 and schaftoside), C,O-glycosylflavones (e.g., chrysoeriol-8-C-glucosyl-2'-0-glucuronide-6-C-arabinoside) and luteolin-7-C,O-rutinoside as the main constituents. Lower levels of oleanane-type saponins, such as soyasaponin Bb and Be, and the saponin derivatives hederagenin and aglycone B, which are typical of Fabaceae family, were also found. From this study, it is suggested that the analgesic effect observed is not due to the terpenoids previously reported from fruit and seed extracts, but could be attributed to flavones and the hederagenin derivatives that were identified as main constituents of the hydroethanolic extract from the leaves. Keywords: Pterodon emarginatus Fabaceae Antinociceptive Di-C-glycosylflavones Di-CO-giycosylflavones Soyasaponins, Introduction The genus Pterodon (Fabaceae/Leguminosae) is widely distributed over the savannahs of central and southern Brazil. Pterodon emarginatus Vogel (synonyms Pterodon pubescens Benth. and Pterodon polygaliflorus Benth.), also known as [...]

ARTICLE INFO Keywords: 18β-Glycyrrhetinic acid C. albicans Adjuvant Th1/Th2 Mice ABSTRACT The aim of this study was to determine the immunological adjuvant effect of 18β-glycyrrhetinic acid (GA) isolated from Glycyrrhizae [...]

Membranes allow the compartmentalization of biochemical processes and are therefore fundamental to life. The conservation of the cellular membrane, combined with its accessibility to secreted proteins, has made it a [...]

Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily--and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming., Understanding soil biogeochemistry is essential to the stewardship of ecosystem services provided by soils, such as soil fertility (for food, fibre and fuel production), water quality, resistance to erosion and [...]

There is much interest in using embryonic stem cells to regenerate tissues and organs. For this approach to succeed, these stem cells or their derivatives must engraft in patients over [...]

Author(s): Yang Xiang [1, 2]; Benoit Laurent [1, 2]; Chih-Hung Hsu [1, 2]; Sigrid Nachtergaele [3, 4, 5]; Zhike Lu [3, 4, 5]; Wanqiang Sheng [1, 2]; Chuanyun Xu [1, [...]

Author(s): Dolors Ferres-Marco [1, 3]; Irene Gutierrez-Garcia [1, 3]; Diana M. Vallejo [1, 3]; Jorge Bolivar [2]; Francisco J. Gutierrez-Aviño [1]; Maria Dominguez (corresponding author) [1] Correct organ formation depends [...]

Author(s): Eric Debayle (corresponding author) [1]; Brian Kennett [2]; Keith Priestley [3] Differences in the thickness of the high-velocity lid underlying continents as imaged by seismic tomography, have fuelled a [...]

In meta-analysis, independently executed historical studies are viewed as imperfect replications of one overall but unplanned experiment. Using empirical parameter estimates of those studies as a unit of analysis, a linear model is specified to uncover systematic variation as a function of study design, data characteristics, model specification, etc. Because of the fallible nature of the historical studies, however, the vector of parameter estimates reflects cross-sectional estimation biases as well as inefficiencies. The outcome of many meta-analyses, therefore, is largely a description of those systematic biases and inefficiencies, a result with little intrinsic scientific value given the fundamental meta-analysis objective of improving understanding of the studied phenomenon. Unfortunately, estimating more scientifically interesting effects on the basis of systematic variation in historical parameter estimates is conditional on the fallible character of the historical studies. This paper provides clarity on what is being estimated in meta-analyses and on how scientifically interesting effects can be estimated unbiasedly using response surface extrapolation in a least squares framework. KEY WORDS: Extrapolation; Least squares; Meta-analysis., INTRODUCTION The objective in meta-analysis is to obtain further insight and understanding into a modeled phenomenon by comparing parameter estimates obtained independently in different empirical studies (Glass, McGaw, and Smith [...]

The global predominance of three donal Toxoplasma gondii lineages suggests that they are endowed with an exceptional trait responsible for their current parasitism of nearly all warm-blooded vertebrates. Genetic polymorphism analyses indicate that these clonal lineages emerged within the last 10,000 years after a single genetic cross. Comparison with ancient strains (~1 million years) suggests that the success of the clonal lineages resulted from the concurrent acquisition of direct oral infectivity. This key adaptation circumvented sexual recombination, simultaneously promoting transmission through successive hosts, hence leading to clonal expansion. Thus, changes in complex life cycles can occur rapidly and can profoundly influence pathogenicity., Toxoplasma gondii is a member of the phylum Apicomplexa, an ancient group of ~5000 species of parasitic protozoa that infect a wide range of vertebrates (1-3). Most closely related members [...]

Author(s): A. Dao [1]; A. S. Yaro [1]; M. Diallo [1]; S. Timbine [1]; D. L. Huestis [2]; Y. Kassogue [1]; A. I. Traore [1]; Z. L. Sanogo [1]; D. [...]

Restrictions to gene flow among molecular forms of the mosquito Anopheles gambiae sensu stricto reveal an ongoing speciation process affecting the epidemiology of malaria in sub-Saharan Africa., The most important vector of the malaria parasite in sub-Saharan Africa is the mosquito Anopheles gambiae sensu stricto (s.s.). It belongs to a group of sibling species--known as the A. [...]

At a recent workshop, experts discussed the benefits, risks, and research priorities associated with using genetically manipulated insects in the control of vector-borne diseases., This is a partial report of a workshop--Genetically Engineered Arthropod Vectors of Human Infectious Diseases--jointly sponsored by the World Health Organization, the MacArthur Foundation, the National Institute of Allergy and [...]

Ecological and population biology issues constitute serious challenges to the application of genetically modified mosquitos (GMM) for disease control., Optimism that mosquito-borne diseases such as malaria, dengue, and filariasis can be effectively controlled or even eradicated with inexpensive drugs, vaccines, or insecticides has been sorely tested (1). The impact [...]

Toxoplasma gondii is a common human pathogen causing serious, even fatal disease in the developing fetus and in immunocompromised patients. Despite its ability to reproduce sexually and its broad geographic and host range, Toxoplasma has a clonal population structure comprised principally of three lines. We have analyzed 15 polymorphic loci in the archetypal type I, II, and III strains and found that polymorphism was limited to, at most, two rather than three allelic classes and no polymorphism was detected between alleles in strains of a given type. Multilocus analysis of 10 nonarchetypal isolates likewise clustered the vast majority of alleles into the same two distinct ancestries. These data strongly suggest that the currently predominant genotypes exist as a pandemic outbreak from a genetic mixing of two discrete ancestral lines. To determine if such mixing could lead to the extreme virulence observed for some strains, we examined the [F.sub.1] progeny of a cross between a type II and III strain, both of which are relatively avirulent in mice. Among the progeny were recombinants that were at least 3 logs more virulent than either parent. Thus, sexual recombination, by combining polymorphisms in two distinct and competing clonal lines, can be a powerful force driving the natural evolution of virulence in this highly successful pathogen., Most parasitic protozoa and many prokaryotic pathogens possess a 'clonal' population genetic structure consisting of independently propagating, genetically quite divergent clonal lineages (1-4). For Toxoplasma gondii, a widespread zoonotic pathogen [...]