364 research outputs found
Uncovering the complex genetics of human character
Human personality is 30-60% heritable according to twin and adoption studies. Hundreds of genetic variants are expected to influence its complex development, but few have been identified. We used a machine learning method for genome-wide association studies (GWAS) to uncover complex genotypic-phenotypic networks and environmental interactions. The Temperament and Character Inventory (TCI) measured the self-regulatory components of personality critical for health (i.e., the character traits of self-directedness, cooperativeness, and self-transcendence). In a discovery sample of 2149 healthy Finns, we identified sets of single-nucleotide polymorphisms (SNPs) that cluster within particular individuals (i.e., SNP sets) regardless of phenotype. Second, we identified five clusters of people with distinct profiles of character traits regardless of genotype. Third, we found 42 SNP sets that identified 727 gene loci and were significantly associated with one or more of the character profiles. Each character profile was related to different SNP sets with distinct molecular processes and neuronal functions. Environmental influences measured in childhood and adulthood had small but significant effects. We confirmed the replicability of 95% of the 42 SNP sets in healthy Korean and German samples, as well as their associations with character. The identified SNPs explained nearly all the heritability expected for character in each sample (50 to 58%). We conclude that self-regulatory personality traits are strongly influenced by organized interactions among more than 700 genes despite variable cultures and environments. These gene sets modulate specific molecular processes in brain for intentional goal-setting, self-reflection, empathy, and episodic learning and memory
Uncovering the complex genetics of human temperament
Experimental studies of learning suggest that human temperament may depend on the molecular mechanisms for associative conditioning, which are highly conserved in animals. The main genetic pathways for associative conditioning are known in experimental animals, but have not been identified in prior genome-wide association studies (GWAS) of human temperament. We used a data-driven machine learning method for GWAS to uncover the complex genotypic-phenotypic networks and environmental interactions related to human temperament. In a discovery sample of 2149 healthy Finns, we identified sets of single-nucleotide polymorphisms (SNPs) that cluster within particular individuals (i.e., SNP sets) regardless of phenotype. Second, we identified 3 clusters of people with distinct temperament profiles measured by the Temperament and Character Inventory regardless of genotype. Third, we found 51 SNP sets that identified 736 gene loci and were significantly associated with temperament. The identified genes were enriched in pathways activated by associative conditioning in animals, including the ERK, PI3K, and PKC pathways. 74% of the identified genes were unique to a specific temperament profile. Environmental influences measured in childhood and adulthood had small but significant effects. We confirmed the replicability of the 51 Finnish SNP sets in healthy Korean (90%) and German samples (89%), as well as their associations with temperament. The identified SNPs explained nearly all the heritability expected in each sample (37-53%) despite variable cultures and environments. We conclude that human temperament is strongly influenced by more than 700 genes that modulate associative conditioning by molecular processes for synaptic plasticity and long-term memory
Elasticity of Diamond at High Pressures and Temperatures
We combine density functional theory within the local density approximation,
the quasiharmonic approximation, and vibrational density of states to calculate
single crystal elastic constants, and bulk and shear moduli of diamond at
simultaneous high pressures and temperatures in the ranges of 0-500 GPa and
0-4800 K. Comparison with experimental values at ambient pressure and high
temperature shows an excellent agreement for the first time with our
first-principles results validating our method. We show that the anisotropy
factor of diamond increases to 40% at high pressures and becomes temperature
independent.Comment: 10 pages, 3 figures, 1 tabl
Three genetic-environmental networks for human personality
Phylogenetic, developmental, and brain-imaging studies suggest that human personality is the integrated expression of three major systems of learning and memory that regulate (1) associative conditioning, (2) intentionality, and (3) self-awareness. We have uncovered largely disjoint sets of genes regulating these dissociable learning processes in different clusters of people with (1) unregulated temperament profiles (i.e., associatively conditioned habits and emotional reactivity), (2) organized character profiles (i.e., intentional self-control of emotional conflicts and goals), and (3) creative character profiles (i.e., self-aware appraisal of values and theories), respectively. However, little is known about how these temperament and character components of personality are jointly organized and develop in an integrated manner. In three large independent genome-wide association studies from Finland, Germany, and Korea, we used a data-driven machine learning method to uncover joint phenotypic networks of temperament and character and also the genetic networks with which they are associated. We found three clusters of similar numbers of people with distinct combinations of temperament and character profiles. Their associated genetic and environmental networks were largely disjoint, and differentially related to distinct forms of learning and memory. Of the 972 genes that mapped to the three phenotypic networks, 72% were unique to a single network. The findings in the Finnish discovery sample were blindly and independently replicated in samples of Germans and Koreans. We conclude that temperament and character are integrated within three disjoint networks that regulate healthy longevity and dissociable systems of learning and memory by nearly disjoint sets of genetic and environmental influences
TRIPOS DENS (OSTENFELD & SCHMIDT) F. GÓMEZ 2013, EN LA COSTA NORTE DEL PERÚ
En el presente trabajo se registra por primera vez el dinoflagelado Tripos dens (Ostenfeld & Schmidt) F. Gómez 2013, en la zona norte del Perú (Máncora-Piura-Perú) a partir del 2013. La identificación de T. dens se realizó mediante un examen morfo-taxonómico detallando sus placas con microscopía de luz; también se comparó con T. balechii, especie con la que se confundió en diversas publicaciones
Production and partial characterization of an exopolysaccharide from Ustilago maydis in submerged culture
In Mexico, corn is widely cultivated and frequently parasitized by Ustilago maydis, a basidiomycete dimorphic fungus that causes the disease known as corn smut. It is widely consumed and is considered a culinary delight. From a biotechnological perspective, U. maydis offers the possibility as a producer of various metabolites, such as laccase and tyrosinase enzymes, glycolipids, and indole derivatives that can be used in pharmaceutical, cosmetic and food, due to its safety. The exopolysaccharides (EPS) are extracellular sugar compounds synthesized by a variety of microorganism and have shown various properties and applications. Among them are the improved rheology, texture, stability and mouthfeel of fermented dairy products. In addition, these compounds have shown biological activity as an antitumor agent, immune-stimulating and reducing blood cholesterol. The production of EPS by U. maydis was studied by culturing the cells in yeast extractpeptone- dextrose (YPD), YPD supplemented with CuSO4 (YPDT), Czapek Dox-sucrose, Czapek Doxglucose, Czapeck Dox culture media with corn steep liquor and in another media containing high oil oleic sunflower as the sole carbon source. The presence of activity of glycosyltransferase by sodium dodecyl sulfate-polyacrylamide gel electrophresis (SDS-PAGE) was detected as well as the polymers formed by dinitrosaliscilic acid (DNS). The products of fermentation were characterized by enzymatic hydrolysis using carbohydrases, gel permation chromatography and atomic force microscopy.Key words: Ustilago maydis, glucans, polymerization, glycosyltransferase, exopolysaccharide
Phytotoxic and dissuasive activity of Chihuahua desert plants
With the purpose of finding plant compounds with the potential use as herbicides and insecticides, a research was realized with the objective of evaluate the phytotoxic and dissuasive activity of four Chihuahua desert plants. The phytotoxic activity evaluation was tested on Lactuca sativa and Lolium perenne, while the dissuasive activity was realized on three species of phytophagous insects: Myzus persicae, Rhopalosiphum padi and Spodoptera littoralis. Raw extracts were used, the solvents hexane, methanol and ethanol of different plants’ organs (root, steam, leaf and flower) of four species: Fouquieria splendens (ocotillo), Larrea tridentate (governor), Astragalus mollissimus (wild grass) and Pachycereus pecten-aboriginum (echo), by the establishment of in vitro bioassays at a concentration of 10 mg/ml extract/solvent. In the toxicity bioassay, the percentage of germination, root and leaf length were measured. The results showed that the leaf extract of L. tridentata had phytotoxic activity for L. sativa, while for L. perenne the phytotoxicity was observed within the ocotillo, governor and echo extracts. In the dissuasive bioassay, each treatment had 20 repetitions with 10 adult insects per repetition. The methanolic extracts of F. splendens leaf and root, ethanolic extract of A. mollisimus sheet and the ethanolic extract of P. pecten-aboriginum stems showed moderate dissuasive response of feeding against M. persicae, presenting a settlement inhibition index of 53.53, 54.35, 60.00 and 48.84% respectively. Nevertheless, the results indicated that none of the 10 extracts tested on S. littoralis showed significant dissuasive properties for this Lepidoptera, while for R. padi all the tested extracts presented dissuasive properties. The treatments of the four vegetable species evaluated showed defensive or dissuasive properties of moderate to strong feeding against the insects M. persicae and R. padi, presenting interesting potential for being used as insecticides, while the tested extracts that presented phytotoxicity for both lettuce and ryegrass present possibilities for the realization of herbicides
A Machine Checked Model of Idempotent MGU Axioms For Lists of Equational Constraints
We present formalized proofs verifying that the first-order unification
algorithm defined over lists of satisfiable constraints generates a most
general unifier (MGU), which also happens to be idempotent. All of our proofs
have been formalized in the Coq theorem prover. Our proofs show that finite
maps produced by the unification algorithm provide a model of the axioms
characterizing idempotent MGUs of lists of constraints. The axioms that serve
as the basis for our verification are derived from a standard set by extending
them to lists of constraints. For us, constraints are equalities between terms
in the language of simple types. Substitutions are formally modeled as finite
maps using the Coq library Coq.FSets.FMapInterface. Coq's method of functional
induction is the main proof technique used in proving many of the axioms.Comment: In Proceedings UNIF 2010, arXiv:1012.455
Chloroquine-containing organoruthenium complexes are fast-acting multistage antimalarial agents
© Cambridge University Press 2016We report the pharmacological activity of organoruthenium complexes containing chloroquine (CQ) as a chelating ligand. The complexes displayed intraerythrocytic activity against CQ-sensitive 3D7 and CQ-resistant W2 strains of Plasmodium falciparum, with potency and selectivity indexes similar to those of CQ. Complexes displayed activity against all intraerythrocytic stages, but moderate activity against Plasmodium berghei liver stages. However, unlike CQ, organoruthenium complexes impaired gametocyte viability and exhibited fast parasiticidal activity against trophozoites for P. falciparum. This functional property results from the ability of complexes to quickly induce oxidative stress. The parasitaemia of P. berghei-infected mice was reduced by treatment with the complex. Our findings demonstrated that using chloroquine for the synthesis of organoruthenium complexes retains potency and selectivity while leading to an increase in the spectrum of action and parasite killing rate relative to CQ.This research was funded by FAPESB (grant PET0042/2013, Brazil) to M.B.P.S, FAPESP (grant 14/10516-7, Brazil) to A.A.B. and Fundação para a Ciência e Tecnologia (grant PTDC/SAU-MIC/117060/2010 Portugal) to M.P. A.A.B. and M.B.P.S. are recipients of senior fellowships by CNPq (Brazil)info:eu-repo/semantics/publishedVersio
The rkpU gene of Sinorhizobium fredii HH103 is required for bacterial K-antigen polysaccharide production and for efficient nodulation with soybean but not with cowpea
In this work, the role of the rkpU and rkpJ genes in the production of the K-antigen
polysaccharides (KPS) and in the symbiotic capacity of Sinorhizobium fredii HH103, a broad
host-range rhizobial strain able to nodulate soybean and many other legumes, was studied. The
rkpJ- and rkpU-encoded products are orthologous to Escherichia coli proteins involved in
capsule export. S. fredii HH103 mutant derivatives were contructed in both genes. To our
knowledge, this is the first time that the role of rkpU in KPS production has been studied in
rhizobia. Both rkpJ and rkpU mutants were unable to produce KPS. The rkpU derivative also
showed alterations in its lipopolysaccharide (LPS). Neither KPS production nor rkpJ and rkpU
expression was affected by the presence of the flavonoid genistein. Soybean (Glycine max) plants
inoculated with the S. fredii HH103 rkpU and rkpJ mutants showed reduced nodulation and clear
symptoms of nitrogen starvation. However, neither the rkpJ nor the rkpU mutants were
significantly impaired in their symbiotic interaction with cowpea (Vigna unguiculata). Thus, we
demonstrate for the first time to our knowledge the involvement of the rkpU gene in rhizobial KPS
production and also show that the symbiotic relevance of the S. fredii HH103 KPS depends on
the specific bacterium–legume interaction
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