342 research outputs found
(Z)-N-(2-Iodophenyl)-4-nitrobenzimidoyl cyanide
In the title molecule, C14H8IN3O2, the cyanide group is anti to the iodide substituent of the adjacent benzene ring. The central segment is essentially planar (r.m.s deviation = 0.0341 A ° ) and it is twisted away from the iodide- and nitro-substituted benzene rings by 69.02 (9) and 15.83 (16), respectively. In the crystal, molecules are linked by weak C—H N interactions, leading to C(8) chains along [010]
New lysosomal acid lipase gene mutants explain the phenotype of Wolman disease and cholesteryl ester storage disease.
Deficiency of lysosomal acid lipase (LAL) leads to either Wolman disease(WD) or the more benign cholesteryl ester storage disease (CESD). To identifythe molecular basis of the different phenotypes we have characterised the LALgene mutations in three new patients with LAL deficiency. A patient with WD washomozygote for a null allele Y303X. The other two patients, with CESD, presentedeither homozygosity for T267I or compound heterozygosity consisting of Q64R andan exon 8 donor splice site substitution (G→A in position–1). The mutants T267I and Q64R and the previously reported L273S, G66V,and H274Y CESD substitutions, overexpressed in stable clones, were found to befully glycosylated and show an enzymatic activity of 3–8% of that ofnormal LAL. On the other hand, the Δ254–277 mutant proteinderived from exon 8 skipping and the Y303X protein were totally inactive. Bytransient transfection of hybrid minigene constructs, the CESD G→A(–1) substitution resulted in partial exon inclusion, thus allowing theproduction of a small amount of normal LAL mRNA and hence of a functionalenzyme. In contrast, a G→Asubstitution observed in WD at position +1 of the same exon 8 donor siteresulted in complete exon skipping and the sole production of an inactiveΔ254–277 protein.In conclusion,LAL genotypes determine the level of residual enzymatic activity, thusexplaining the severity of the phenotype.—Pagani, F., R. Pariyarath, R.Garcia, C. Stuani, A. B. Burlina, G. Ruotolo, M. Rabusin, and F. E. Baralle. Newlysosomal acid lipase gene mutants explain the phenotype of Wolman disease andcholesteryl ester storage disease. J. Lipid Res. 1998. 39:1382–1388
Sites for gamma-ray astronomy in Argentina
We have searched for possible sites in Argentina for the installation of large air Cherenkov telescope arrays and water Cherenkov systems. At present seven candidates are identified at altitudes from 2500 to 4500 m. The highest sites are located at the NW of the country, in La Puna. Sites at 2500 and 3100 m are located in the West at El Leoncito Observatory, with excellent infrastructure. A description of these candidate sites is presented with emphasis on infrastructure and climatology.Fil: Rovero, Adrian Carlos. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de AstronomĂa y FĂsica del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de AstronomĂa y FĂsica del Espacio; ArgentinaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. GobernaciĂłn. ComisiĂłn de Investigaciones CientĂficas. Instituto Argentino de RadioastronomĂa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto Argentino de RadioastronomĂa; ArgentinaFil: Allekotte, Ingomar. ComisiĂłn Nacional de EnergĂa AtĂłmica. Centro AtĂłmico Bariloche; ArgentinaFil: Bertou, Xavier Pierre Louis. ComisiĂłn Nacional de EnergĂa AtĂłmica. Centro AtĂłmico Bariloche; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Colombo, E.. ComisiĂłn Nacional de EnergĂa AtĂłmica. Centro AtĂłmico Constituyentes; ArgentinaFil: Etchegoyen, A.. ComisiĂłn Nacional de EnergĂa AtĂłmica. Centro AtĂłmico Constituyentes; ArgentinaFil: Garcia, B.. Universidad TecnolĂłgica Nacional; ArgentinaFil: Garcia Lambas, Diego Rodolfo. Universidad Nacional de CĂłrdoba; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de AstronomĂa TeĂłrica y Experimental. Universidad Nacional de CĂłrdoba. Observatorio AstronĂłmico de CĂłrdoba. Instituto de AstronomĂa TeĂłrica y Experimental; ArgentinaFil: Levato, Orlando Hugo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Juan. Complejo AstronĂłmico "El Leoncito". Universidad Nacional de CĂłrdoba. Complejo AstronĂłmico "El Leoncito". Universidad Nacional de la Plata. Complejo AstronĂłmico "El Leoncito". Universidad Nacional de San Juan. Complejo AstronĂłmico "El Leoncito"; ArgentinaFil: Medina, M. C.. Centre National de la Recherche Scientifique. Observatoire de Paris; FranciaFil: Muriel, Hernan. Universidad Nacional de CĂłrdoba; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de AstronomĂa TeĂłrica y Experimental. Universidad Nacional de CĂłrdoba. Observatorio AstronĂłmico de CĂłrdoba. Instituto de AstronomĂa TeĂłrica y Experimental; ArgentinaFil: Recabarren, Pablo Genaro Antonio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de AstronomĂa TeĂłrica y Experimental. Universidad Nacional de CĂłrdoba. Observatorio AstronĂłmico de CĂłrdoba. Instituto de AstronomĂa TeĂłrica y Experimental; Argentina. Universidad Nacional de CĂłrdoba; Argentin
Study of a Nonlocal Density scheme for electronic--structure calculations
An exchange-correlation energy functional beyond the local density
approximation, based on the exchange-correlation kernel of the homogeneous
electron gas and originally introduced by Kohn and Sham, is considered for
electronic structure calculations of semiconductors and atoms. Calculations are
carried out for diamond, silicon, silicon carbide and gallium arsenide. The
lattice constants and gaps show a small improvement with respect to the LDA
results.
However, the corresponding corrections to the total energy of the isolated
atoms are not large enough to yield a substantial improvement for the cohesive
energy of solids, which remains hence overestimated as in the LDA.Comment: 4 postscript figure
Reversing age: Dual species measurement of epigenetic age with a single clock
Young blood plasma is known to confer beneficial effects on various organs in mice. However, it was not known whether young plasma rejuvenates cells and tissues at the epigenetic level; whether it alters the epigenetic clock, which is a highly-accurate molecular biomarker of aging. To address this question, we developed and validated six different epigenetic clocks for rat tissues that are based on DNA methylation values derived from n=593 tissue samples. As indicated by their respective names, the rat pan-tissue clock can be applied to DNA methylation profiles from all rat tissues, while the rat brain-, liver-, and blood clocks apply to the corresponding tissue types. We also developed two epigenetic clocks that apply to both human and rat tissues by adding n=850 human tissue samples to the training data. We employed these six clocks to investigate the rejuvenation effects of a plasma fraction treatment in different rat tissues. The treatment more than halved the epigenetic ages of blood, heart, and liver tissue. A less pronounced, but statistically significant, rejuvenation effect could be observed in the hypothalamus. The treatment was accompanied by progressive improvement in the function of these organs as ascertained through numerous biochemical/physiological biomarkers and behavioral responses to assess cognitive functions. Cellular senescence, which is not associated with epigenetic aging, was also considerably reduced in vital organs. Overall, this study demonstrates that a plasma-derived treatment markedly reverses aging according to epigenetic clocks and benchmark biomarkers of aging.Fil: Horvath, Steve. University of California at Los Angeles; Estados UnidosFil: Singh, Kavita. NMIMS University; IndiaFil: Raj, Ken. Public Health England; Reino UnidoFil: Khairnar, Shraddha. NMIMS University; IndiaFil: Sanghav, Akshay. Nugenics Research Pvt Ltd; IndiaFil: Shrivastava, Agnivesh. Nugenics Research Pvt Ltd; IndiaFil: Zoller, Joseph A.. University of California at Los Angeles; Estados UnidosFil: Li, Caesar Z.. University of California at Los Angeles; Estados UnidosFil: Hereñú, Claudia Beatriz. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de FarmacologĂa Experimental de CĂłrdoba. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Instituto de FarmacologĂa Experimental de CĂłrdoba; ArgentinaFil: Canatelli Mallat, Martina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Lehmann, Marianne. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Solberg Woods, Leah C.. Wake Forest University School of Medicine; Estados UnidosFil: Garcia Martinez, Angel. University of Tennessee; Estados UnidosFil: Wang, Tengfei. University of Tennessee; Estados UnidosFil: Chiavellini, Priscila. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Levine, Andrew J.. University of California at Los Angeles; Estados UnidosFil: Chen, Hao. University of Tennessee; Estados UnidosFil: Goya, Rodolfo Gustavo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Katcher, Harold L.. Nugenics Research Pvt Ltd; Indi
Observations of the First Electromagnetic Counterpart to a Gravitational-wave Source by the TOROS Collaboration
We present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration. We detected highly significant dimming in the light curves of the counterpart (Δg = 0.17 ± 0.03 mag, Δr = 0.14 ± 0.02 mag, Δi = 0.10 ± 0.03 mag) over the course of only 80 minutes of observations obtained ∼35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ∼59 hr after the event with the EABA 1.5 m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a \ blue kilonova\ relatively free of lanthanides
Molecular Genetic Variability, Population Structure and Mating System in Tropical Forages
Microsatellite (SSR) markers were developed for the following tropical forage species, using accessions available from the plant genetic resources (PGR) collections held by EMBRAPA (Brazilian Agricultural Research Corporation): Brachiaria brizantha, B. humidicola, Panicum maximum, Paspalum spp., Stylosanthes capitata, S. guianensis, S. macrocephala, Calopogonium mucunoides and Centrosema spp. The markers were used to analyse population structure and genetic diversity, evolution and origin of the genetic variability in the centre of origin, mating systems and genetic resources in EMBRAPA’s germplasm bank. The results shed light on the amount of genetic variation within and between populations, revealed the need in some cases for further plant collection to adequately represent the species in PGR collections, allowed us to assemble core collections (subsets of the total collections) that should contain most of the available diversity and (in the case of the legumes) showed the need to avoid unwanted outcrossing when regenerating conserved material. The data will allow plant breeders to better select accessions for hybrid production, discriminate between genotypes and use marker-assisted selection in breeding programs. Our results will also underpin the construction of genetic maps, mapping of genes of agronomic interest and numerous other studies on genetic variability, population structure, gene flow and reproductive systems for the tropical forage species studied in this work
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
Does Selection against Transcriptional Interference Shape Retroelement-Free Regions in Mammalian Genomes?
BACKGROUND: Eukaryotic genomes are scattered with retroelements that proliferate through retrotransposition. Although retroelements make up around 40 percent of the human genome, large regions are found to be completely devoid of retroelements. This has been hypothesised to be a result of genomic regions being intolerant to insertions of retroelements. The inadvertent transcriptional activity of retroelements may affect neighbouring genes, which in turn could be detrimental to an organism. We speculate that such retroelement transcription, or transcriptional interference, is a contributing factor in generating and maintaining retroelement-free regions in the human genome. METHODOLOGY/PRINCIPAL FINDINGS: Based on the known transcriptional properties of retroelements, we expect long interspersed elements (LINEs) to be able to display a high degree of transcriptional interference. In contrast, we expect short interspersed elements (SINEs) to display very low levels of transcriptional interference. We find that genomic regions devoid of long interspersed elements (LINEs) are enriched for protein-coding genes, but that this is not the case for regions devoid of short interspersed elements (SINEs). This is expected if genes are subject to selection against transcriptional interference. We do not find microRNAs to be associated with genomic regions devoid of either SINEs or LINEs. We further observe an increased relative activity of genes overlapping LINE-free regions during early embryogenesis, where activity of LINEs has been identified previously. CONCLUSIONS/SIGNIFICANCE: Our observations are consistent with the notion that selection against transcriptional interference has contributed to the maintenance and/or generation of retroelement-free regions in the human genome
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