1,274 research outputs found
The basic genetic toolkit to move in with your photosynthetic partner
The origin of photosynthetic organelles via endosymbiosis more than 1 Gya ago was a major detonator of eukaryotic diversification. The evolution of a stable endosymbiotic relationship between eukaryotic cells and photosynthetic cyanobacteria involved series of cellular and molecular processes that are not entirely understood. Critical steps towards the evolution of plastids occurred when the host cell gained genetic and metabolic control over the captured cyanobacterium. Proteins recruited from the host repertoire had major roles initiating the metabolite exchange between both symbiotic partners. Concurrently, the relocation of certain cyanobacterial genes into the host nuclear genome was critical to coordinate the division of the endosymbiotic cells and the transit of nuclear-encoded proteins into the novel organelle. This review explores diverse studies that have identified key endosymbiosis genes and discusses the putative roles of the encoded proteins during the early evolution of plastids. The understanding of the regulation mechanisms and functions of the endosymbiosis genes will shed light on the design of genetic engineering approaches to facilitate endosymbiotic associations
Circadian gene expression of tryptophan hydroxylase 2 in the Dorsal and Median Raphe nuclei is altered by dysregulated glucocorticoid rhythms
Elements of Biblical Exegesis: A Basic Guide for Students and Ministers [review] / Michael J. Gorman
Asymmetric Organocatalysis: A Survival Guide to Medicinal Chemists
Majority of drugs act by interacting with chiral counterparts, e.g., proteins, and we are, unfortunately, well-aware of how chirality can negatively impact the outcome of a therapeutic regime. The number of chiral, non-racemic drugs on the market is increasing, and it is becoming ever more important to prepare these compounds in a safe, economic, and environmentally sustainable fashion. Asymmetric organocatalysis has a long history, but it began its renaissance era only during the first years of the millennium. Since then, this field has reached an extraordinary level, as confirmed by the awarding of the 2021 Chemistry Nobel Prize. In the present review, we wish to highlight the application of organocatalysis in the synthesis of enantio-enriched molecules that may be of interest to the pharmaceutical industry and the medicinal chemistry community. We aim to discuss the different activation modes observed for organocatalysts, examining, for each of them, the generally accepted mechanisms and the most important and developed reactions, that may be useful to medicinal chemists. For each of these types of organocatalytic activations, select examples from academic and industrial applications will be disclosed during the synthesis of drugs and natural products
Multiple Genes of Apparent Algal Origin Suggest Ciliates May Once Have Been Photosynthetic
SummaryPlantae (as defined by Cavalier-Smith, 1981) [1] plastids evolved via primary endosymbiosis whereby a heterotrophic protist enslaved a photosynthetic cyanobacterium. This “primary” plastid spread into other eukaryotes via secondary endosymbiosis. An important but contentious theory in algal evolution is the chromalveolate hypothesis that posits chromists (cryptophytes, haptophytes, and stramenopiles) and alveolates (ciliates, apicomplexans, and dinoflagellates) share a common ancestor that contained a red-algal-derived “secondary” plastid [2]. Under this view, the existence of several later-diverging plastid-lacking chromalveolates such as ciliates and oomycetes would be explained by plastid loss in these lineages. To test the idea of a photosynthetic ancestry for ciliates, we used the 27,446 predicted proteins from the macronuclear genome of Tetrahymena thermophila to query prokaryotic and eukaryotic genomes. We identified 16 proteins of possible algal origin in the ciliates Tetrahymena and Paramecium tetraurelia. Fourteen of these are present in other chromalveolates. Here we compare and contrast the likely scenarios for algal-gene origin in ciliates either via multiple rounds of horizontal gene transfer (HGT) from algal prey or symbionts, or through endosymbiotic gene transfer (EGT) during a putative photosynthetic phase in their evolution
The Glaucophyta: the blue-green plants in a nutshell
The Glaucophyta is one of the three major lineages of photosynthetic eukaryotes, together with viridiplants and red algae, united in the presumed monophyletic supergroup Archaeplastida. Glaucophytes constitute a key algal lineage to investigate both the origin of primary plastids and the evolution of algae and plants. Glaucophyte plastids possess exceptional characteristics retained from their cyanobacterial ancestor: phycobilisome antennas, a vestigial peptidoglycan wall, and carboxysome-like bodies. These latter two traits are unique among the Archaeplastida and have been suggested as evidence that the glaucophytes diverged earliest during the diversification of this supergroup. Our knowledge of glaucophytes is limited compared to viridiplants and red algae, and this has restricted our capacity to untangle the early evolution of the Archaeplastida. However, in recent years novel genomic and functional data are increasing our understanding of glaucophyte biology. Diverse comparative studies using information from the nuclear genome of Cyanophora paradoxa and recent transcriptomic data from other glaucophyte species provide support for the common origin of Archaeplastida. Molecular and ultrastructural studies have revealed previously unrecognized diversity in the genera Cyanophora and Glaucocystis. Overall, a series of recent findings are modifying our perspective of glaucophyte diversity and providing fresh approaches to investigate the basic biology of this rare algal group in detail
Synovial chondromatosis of the temporomandibular joint
La condromatosis sinovial (CS) es una enfermedad de etiología desconocida, la cual pude definirse como un proceso benigno sinovial caracterizado por la formación de nódulos cartilaginosos metaplásicos dentro del tejido conectivo de las superficies articulares, se le considera un fenómeno metaplásico activo más que un proceso neoplásico; presenta una marcada preferencia por afectar a mujeres constituyendo casi el 70% de los casos reportados, el rango de edad es amplio y oscila entre los 18 y 75 años con una media de 44.6 años. Dentro de los principales hallazgos clínicos destacan: sintomatología dolorosa, presencia de crepitación, aumento de volumen y limitación de la apertura bucal. La CS es una entidad poco frecuente de la cual se han reportado no más de 75 casos en la literatura inglesa, sólo 66 de ellos comprobados histológicamente, la mayoría afectando principalmente grandes articulaciones como cadera, rodilla y hombro; pero si la frecuencia es rara en estas localizaciones, lo es más aún en la articulación temporomandibular. El objetivo del presente artículo es el de reportar un caso clínico a la vez que se realiza una breve revisión de la literatura
Chlamydiae Has Contributed at Least 55 Genes to Plantae with Predominantly Plastid Functions
BACKGROUND:The photosynthetic organelle (plastid) originated via primary endosymbiosis in which a phagotrophic protist captured and harnessed a cyanobacterium. The plastid was inherited by the common ancestor of the red, green (including land plants), and glaucophyte algae (together, the Plantae). Despite the critical importance of primary plastid endosymbiosis, its ancient derivation has left behind very few "footprints" of early key events in organelle genesis. METHODOLOGY/PRINCIPAL FINDINGS:To gain insights into this process, we conducted an in-depth phylogenomic analysis of genomic data (nuclear proteins) from 17 Plantae species to identify genes of a surprising provenance in these taxa, Chlamydiae bacteria. Previous studies show that Chlamydiae contributed many genes (at least 21 in one study) to Plantae that primarily have plastid functions and were postulated to have played a fundamental role in organelle evolution. Using our comprehensive approach, we identify at least 55 Chlamydiae-derived genes in algae and plants, of which 67% (37/55) are putatively plastid targeted and at least 3 have mitochondrial functions. The remainder of the proteins does not contain a bioinformatically predicted organelle import signal although one has an N-terminal extension in comparison to the Chlamydiae homolog. Our data suggest that environmental Chlamydiae were significant contributors to early Plantae genomes that extend beyond plastid metabolism. The chlamydial gene distribution and protein tree topologies provide evidence for both endosymbiotic gene transfer and a horizontal gene transfer ratchet driven by recurrent endoparasitism as explanations for gene origin. CONCLUSIONS/SIGNIFICANCE:Our findings paint a more complex picture of gene origin than can easily be explained by endosymbiotic gene transfer from an organelle-like point source. These data significantly extend the genomic impact of Chlamydiae on Plantae and show that about one-half (30/55) of the transferred genes are most closely related to sequences emanating from the genome of the only environmental isolate that is currently available. This strain, Candidatus Protochlamydia amoebophila UWE25 is an endosymbiont of Acanthamoeba and likely represents the type of endoparasite that contributed the genes to Plantae
Asymmetric Organocatalysis: A Survival Guide to Medicinal Chemists
Majority of drugs act by interacting with chiral counterparts, e.g., proteins, and we are, unfortunately, well-aware of how chirality can negatively impact the outcome of a therapeutic regime. The number of chiral, non-racemic drugs on the market is increasing, and it is becoming ever more important to prepare these compounds in a safe, economic, and environmentally sustainable fashion. Asymmetric organocatalysis has a long history, but it began its renaissance era only during the first years of the millennium. Since then, this field has reached an extraordinary level, as confirmed by the awarding of the 2021 Chemistry Nobel Prize. In the present review, we wish to highlight the application of organocatalysis in the synthesis of enantio-enriched molecules that may be of interest to the pharmaceutical industry and the medicinal chemistry community. We aim to discuss the different activation modes observed for organocatalysts, examining, for each of them, the generally accepted mechanisms and the most important and developed reactions, that may be useful to medicinal chemists. For each of these types of organocatalytic activations, select examples from academic and industrial applications will be disclosed during the synthesis of drugs and natural products.The authors acknowledge the Spanish Agencia Estatal de Investigación (FEDER-PID2020-118422-GB-I00), the Basque Government (Grupos IT1558-22), and the University of Bologna for financial support
Viaje a España y Portugal : 1912
Contiene : Conferencia leída en el Círculo de la Unijón Mercantil e Industrial enla noche del 16 de Octubre de 1912] / R. Reyes ; [Discursos pronunciados en el banquete ofrecido por el Centro Hispano-Americano a los Delegados al Centenario de las Cortes de Cádiz y al General Rafael Reyes / Blanca de los Ríos de Lampérez ; General Reyes]. Fiesta Hispano-Americana : [Artículo publicado] en el Liberal de Madrid del 14 Octubre 1912.Colombia y el Canal de Panamá [artículo publicado en ] El Imparcial de Madrid de 13 de Octubre de 1912. El Canal de Panamá : [Artículo publicado en] El Imparcial de 16 de Octubre de 1912. Proyecto de Universidad Ibero-Americana complementaria de ampliación e investighación científico-filosófica : [Artículo publicado en] La Evolución de 12 de julio de 1910 / Horacio Bentanvol y Ureta.Salamanca : [Artículo publicado en] El Adelanto de Salamanca 7 de Octubre de 1912 / Miguel A. Otero ( Compañero de viaje del General Reyes). Don Rafael Reyes : [Articulo publicado en] La Crónica General de ESpaña de octubre de 1912. El General Reyes, ex Presidente de Colombia : [Artículo] del diario O Seculo de Lisboa. Juicios e informaciones de la Prensa de Madrid a propósito de la Conferencia dada en el Círculo de la Unión Mercantil e Industrial en la noche del 16 de Octubre de 1912El folleto recoge el eco de la prensa nacional en torno a la visita del General Reyes a España con motivo de los actos de conmemoración del I Centenario de las Cortes de Cádiz.Copia digital : Diputación de Málaga. Biblioteca Canovas del Castillo, 2015Algunas anotaciones mss.--Sello de la Sociedad Económica Gaditana de Amigos del País en la portdilla, portada y páginas interiore
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