84 research outputs found
Fine structure of the utricles and gametogenesis of Codium decorticatum (Caulerpales, Chlorophyta)
Codium decorticatum utricles exhibited a large central vacuole surrounded by a thin parietal layer of cytoplasm. Nuclei and other organelles were placed in the outermost portion of the cytoplasm whereas chloroplasts protruded into the vacuole. The utricle cell wall was formed by a single stratum covered by a rugose cuticle. Only gametangia producing a single type of gametes were observed. Progametangia consisted of an apical vacuolate portion and a basal portion with partitioned cytoplasm. The clear apical portion of immature gametangia revealed abundant endoplasmic reticulum, dictyosomes and electron translucent vacuoles. Most of the gametangium volume was occupied by spherical nuclei and small chloroplasts. Gametes were delimitated by the activity of electron translucent vesicles. Mature gametes were pear-shaped with a prominent papilla occupied by the basal apparatus. An anterior nucleus was anteriorly flanked by a large mitochondrion. Spherical non-flagellate cells with a discrete cover were also observed in the gametangia. The gametes of Codium decorticatum resemble the male gametes of other siphonous green algae, in the flagellar apparatus morphology, in the appearance of the capping plate and the structure and location of the terminal caps, and in the presence of one large mitochondrion. We can assert that the Atlantic Argentinian populations produce only male gametes. Therefore, agamic germination of male gametes would be the only asexual reproduction mechanism of the Argentinian populations. Further studies are necessary to confirm the hypothesis that these populations reproduce asexually by germination of only one type of cell, male gametes that in this case may be functionally considered zoospores
Productividad, estado trófico y dinámica fitoplanctónica en la laguna Sauce Grande y su afluente homónimo (pcia. de Buenos Aires, Argentina)
The shallow lake Sauce Grande is located in the southwest of Buenos Aires province. It is a widening of the Sauce Grande River that flows in and out of the lake. The aim of this study is to estimate for the first time the primary productivity (PP) of this lake and to contrast the physiochemical variables, phytoplankton structure and trophic status with those of its main tributary. Monthly samplings (April-September 2014) were performed in the middle basin of the river and on the coast of the lake. We recorded in situ physical and chemical parameters with a multisensor Horiba U-10. Phytoplankton samples were collected with a plankton net for the qualitative study and with plastic bottles for quantitative analysis.The greatest physicochemical differences corresponded to turbidity and conductivity with values of 581.3 NTU and 9 mS/cm for the lake and 17.7 and 1.7, for the river. The average PP in the lake was 252.1 mg C/m3.h. Cyanobacteria were the most abundant taxonomic group in both systems, although its abundance was greater in the shallow lake. The Carlson index, based on the concentration of chlorophyll a and total phosphorus, identifies the lake as eutrophic, while the river was classified as oligo-mesotrophic according to the same variables. Our results suggest that the Sauce Grande Lake is an autotrophic system with a highly productive metabolism. The remaining production becomes biomass and accumulates within the system, in the form of high levels of phytoplankton abundance, in particular a massive proliferation of Cyanobacteria.The shallow lake Sauce Grande is located in the southwest of Buenos Aires province. It is a widening of the Sauce Grande River that flows in and out of the lake. The aim of this study is to estimate for the first time the primary productivity (PP) of this lake and to contrast the physiochemical variables, phytoplankton structure and trophic status with those of its main tributary. Monthly samplings (April-September 2014) were performed in the middle basin of the river and on the coast of the lake. We recorded in situ physical and chemical parameters with a multisensor Horiba U-10. Phytoplankton samples were collected with a plankton net for the qualitative study and with plastic bottles for quantitative analysis.The greatest physicochemical differences corresponded to turbidity and conductivity with values of 581.3 NTU and 9 mS/cm for the lake and 17.7 and 1.7, for the river. The average PP in the lake was 252.1 mg C/m3 .h. Cyanobacteria were the most abundant taxonomic group in both systems, although its abundance was greater in the shallow lake. The Carlson index, based on the concentration of chlorophyll a and total phosphorus, identifies the lake as eutrophic, while the river was classified as oligo-mesotrophic according to the same variables. Our results suggest that the Sauce Grande Lake is an autotrophic system with a highly productive metabolism. The remaining production becomes biomass and accumulates within the system, in the form of high levels of phytoplankton abundance, in particular a massive proliferation of Cyanobacteria
The RNA-binding profile of Acinus, a peripheral component of the Exon junction complex, reveals its role in splicing regulation
Acinus (apoptotic chromatin condensation inducer in the nucleus) is an RNA-binding protein (RBP) originally identified for its role in apoptosis. It was later found to be an auxiliary component of the exon junction complex (EJC), which is deposited at exon junctions as a consequence of pre-mRNA splicing. To uncover the cellular functions of Acinus and investigate its role in splicing, we mapped its endogenous RNA targets using the cross-linking immunoprecipitation protocol (iCLIP). We observed that Acinus binds to pre-mRNAs, associating specifically to a subset of suboptimal introns, but also to spliced mRNAs. We also confirmed the presence of Acinus as a peripheral factor of the EJC. RNA-seq was used to investigate changes in gene expression and alternative splicing following siRNA-mediated depletion of Acinus in HeLa cells. This analysis revealed that Acinus is preferentially required for the inclusion of specific alternative cassette exons and also controls the faithful splicing of a subset of introns. Moreover, a large number of splicing changes can be related to Acinus binding, suggesting a direct role of Acinus in exon and intron definition. In particular, Acinus regulates the splicing of DFFA/ICAD transcript, a major regulator of DNA fragmentation. Globally, the genome-wide identification of RNA targets of Acinus revealed its role in splicing regulation as well as its involvement in other cellular pathways, including cell cycle progression. Altogether, this study uncovers new cellular functions of an RBP transiently associated with the EJC.J.F.C. was supported by Core funding from the Medical Research Council and by the Wellcome Trust (grant 095518/Z/11/Z). B.J.B. was supported by grants from the CIHR (Canadian Institutes of Health Research). B.J.B. holds the Banbury Chair in Medical Research at the University of Toronto. E.E. was supported by MINECO (Ministerio de Economía y Competitividad) and FEDER (Fondo Europeo de Desarrollo Regional) through grant BIO2014-52566-R, by Sandra Ibarra Foundation for Cancer, and by AGAUR (Agència de Gestió d'Ajuts Universitaris i de Recerca) through grant 2014-SGR1121
Is the grass greener on the other side?
Consumer xenocentrism, the belief that the foreign is preferred over the local, is a relatively new construct in the broader country of origin literature. We extend the study of consumer xenocen- trism to Paraguay (South America), an often bypassed and un- derstudied emerging market. Through a purposive survey of 397 middle- and upper-class Paraguayans in 2022, we uncover the existence of consumer xenocentrism and model its relationship to product judgment of regional powers (Argentina and Brazil) and economic superpowers (China and the United States). Our results indicate a positive and significant relationship between Paraguayan consumer xenocentrism and product judgments of Argentina, Brazil, and the United States, but not for China. Mana- gerial and public policy implications of our findings are discussed
Confined benzene within InOF-1: Contrasting CO2 and SO2 capture behaviours
The confinement of small amounts of benzene in InOF-1 (Bz@InOF-1) shows a contradictory behavior in the capture of CO2 and SO2. While the capture of CO2 is increased 1.6 times, compared to the pristine material, the capture of SO2 shows a considerable decrease. To elucidate these behaviors, the interactions of CO2 and SO2 with Bz@InOF-1 were studied by DFT periodical calculations postulating a plausible explanation: (a) in the case of benzene and CO2, these molecules do not compete for the preferential adsorption sites within InOF-1, providing a cooperative CO2 capture enhancement and (b) benzene and SO2 strongly compete for these preferential adsorption sites inside the MOF material, reducing the total SO2 capture
DGCR8 HITS-CLIP reveals novel functions for the Microprocessor
The Drosha-DGCR8 complex (Microprocessor) is required for microRNA (miRNA) biogenesis. DGCR8 recognizes the RNA substrate, whereas Drosha functions as the endonuclease. High-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) was used to identify RNA targets of DGCR8 in human cells. Unexpectedly, miRNAs were not the most abundant targets. DGCR8-bound RNAs also comprised several hundred mRNAs as well as snoRNAs and long non-coding RNAs. We found that the Microprocessor controls the abundance of several mRNAs as well as of MALAT-1. By contrast, DGCR8-mediated cleavage of snoRNAs is independent of Drosha, suggesting the involvement of DGCR8 in cellular complexes with other endonucleases. Interestingly, binding of DGCR8 to cassette exons, acts as a novel mechanism to regulate the relative abundance of alternatively spliced isoforms. Collectively, these data provide new insights in the complex role of DGCR8 in controlling the fate of several classes of RNAs
Temporal variations of vegetative features, sex ratios and reproductive phenology in a Dictyota dichotoma (Dictyotales, Phaeophyceae) population of Argentina
This paper addresses the phenology of a Dictyota dichotoma population from the North Patagonian coasts of Argentina. The morphology of the individuals was characterized, and analyses of the temporal variations of vegetative features, diploid and haploid life cycle generations and sex ratios are provided. Individuals, represented by growing sporophytes and gametophytes, occurred simultaneously throughout the year. Morphological variables showed temporal variation, except the width and height of medullary cells, which did not vary between seasons. All vegetative variables were significantly correlated with daylength. Besides, frond length, frond dry mass and apical and basal branching angles were significantly correlated with seawater temperatures. Vegetative thalli were less abundant than haploid and diploid thalli. Sporophytes were less abundant than male and female gametophytes. Male gametophytes dominated in May, August, October and January, and female gametophytes were more abundant in September, November, December, February and March. The formation of female gametangia showed a significant correlation with daylength, and the highest number of gametangia was registered in spring. In general, the male/female sex ratio varied between 1:2 and 1:1. Apical regions were more fertile than basal regions. Our data about frequency in the formation of reproductive structures and male/female ratios are the first recorded in the Dictyota genus and thus could not be compared with populations from other regions of the world. Significant morphological variation was observed in thalli of both life cycle generations, regarding length and dry mass, number of primary branches and branching basal angle. In general, all variables analyzed varied seasonally except cortical cell width.Fil: Gauna, Maria Cecilia. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ecología Acuática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Caceres, Eduardo Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ficología y Micología; ArgentinaFil: Parodi, Elisa Rosalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ecología Acuática; Argentin
Detection of kinase domain mutations in BCR::ABL1 leukemia by ultra-deep sequencing of genomic DNA
The screening of the BCR::ABL1 kinase domain (KD) mutation has become a routine analysis in case of warning/failure for chronic myeloid leukemia (CML) and B-cell precursor acute lymphoblastic leukemia (ALL) Philadelphia (Ph)-positive patients. In this study, we present a novel DNA-based next-generation sequencing (NGS) methodology for KD ABL1 mutation detection and monitoring with a 1.0E−4 sensitivity. This approach was validated with a well-stablished RNA-based nested NGS method. The correlation of both techniques for the quantification of ABL1 mutations was high (Pearson r = 0.858, p < 0.001), offering DNA-DeepNGS a sensitivity of 92% and specificity of 82%. The clinical impact was studied in a cohort of 129 patients (n = 67 for CML and n = 62 for B-ALL patients). A total of 162 samples (n = 86 CML and n = 76 B-ALL) were studied. Of them, 27 out of 86 harbored mutations (6 in warning and 21 in failure) for CML, and 13 out of 76 (2 diagnostic and 11 relapse samples) did in B-ALL patients. In addition, in four cases were detected mutation despite BCR::ABL1 < 1%. In conclusion, we were able to detect KD ABL1 mutations with a 1.0E−4 sensitivity by NGS using DNA as starting material even in patients with low levels of disease.Tis project was funded in part by CRIS CANCER FOUNDATION
Modes, mechanisms and evidence of bet hedging in rotifer diapause traits
In this contribution, we review our knowledge on bet-hedging strategies associated with rotifer diapause. First, we describe the ecological scenario under which bet hedging is likely to have evolved in three diapause-related traits in monogonont rotifer populations: (1) the timing of sex (because diapausing eggs are produced via sexual reproduction), (2) the sexual reproduction ratio (i.e. the fraction of sexually reproducing females) and (3) the timing of diapausing egg hatching. Then, we describe how to discriminate among bet-hedging modes and discuss which modes and mechanisms better fit the variability observed in these traits in rotifers. Finally, we evaluate the strength of the empirical evidence for bet hedging in the scarce studies available, and we call for the need of research at different levels of biological complexity to fully understand bet hedging in rotifer diapause
Diagnóstico y tratamiento de la retinopatía diabética y edema macular diabético: guía de práctica clínica del Seguro Social de Salud del Perú (EsSalud)
Introducción. El presente artículo resume la guía de práctica clínica (GPC) para el diagnóstico y tratamiento de la retinopatía diabética y el edema macular diabético en el Seguro Social de Salud del Perú (EsSalud). Objetivo. Proveer recomendaciones clínicas basadas en evidencia para el diagnóstico y tratamiento de la retinopatía diabética y el edema macular diabético en EsSalud. Métodos. Se conformó un grupo elaborador de la guía (GEG) que incluyó médicos especialistas y metodólogos. El GEG formuló 4 preguntas clínicas a ser respondidas por la presente GPC. Para cada una de estas preguntas se realizó búsquedas de revisiones sistemáticas y de estudios primarios (cuando se consideró pertinente) en PubMed durante el 2018. Se seleccionó la evidencia para responder cada una de las preguntas clínicas planteadas. La certeza de la evidencia fue evaluada usando la metodología Grading of Recommendations Assessment, Development, and Evaluation (GRADE). En reuniones de trabajo periódicas, el GEG usó la metodología GRADE para revisar la evidencia y formular las recomendaciones, los puntos de buena práctica clínica y el flujograma de manejo. Resultados. La presente GPC abordó 4 preguntas clínicas sobre el tamizaje, diagnóstico, tratamiento de elección y tratamiento adyuvante. En base a estas preguntas se formularon 6 recomendaciones (4 fuertes y 2 condicionales), 19 puntos de buena práctica clínica y 1 flujograma de manejo. Conclusión. El presente artículo resume la metodología y las conclusiones basadas en evidencias de la GPC para el diagnóstico y tratamiento de la retinopatía diabética y el edema macular diabético en EsSalud
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