Characterizing an Alternative Chloroplast Outer Membrane Targeting Signal in Arabidopsis thaliana

Chloroplasts are organelles that are unique to plant and algal cells and are the site of photosynthesis. Though chloroplasts contain their own genome, an estimated 95% of chloroplast proteins are encoded in the nucleus, and therefore rely on post-translational targeting to the organelle. The majority of known chloroplast proteins are targeted to the chloroplast interior by cleavable signals at the N-terminal end of preproteins known as transit peptides. The translocon at the outer envelope membrane of chloroplasts (Toc) is a multimeric complex that recognizes and binds N-terminal transit peptides at the cytosolic surface of chloroplasts. Though transit peptides are necessary and sufficient for guiding nuclear-encoded preproteins into the chloroplast interior, the nature of sequence information of transit peptides is not fully understood due to their high divergence in length and composition. Over the last nine years, the number of proteins known or predicted to reside in the chloroplast outer envelope membrane of Arabidopsis has tripled to one hundred and seventeen. Although the functions for some of these outer envelope proteins (OEPs) have been characterized, the precise mechanism of their targeting to the chloroplast outer membrane has not been fully elucidated. Besides Toc75, the targeting mechanisms used by OEPs that have been characterized do not involve an N-terminal transit peptide. The bioinformatics tool ChloroP can be used to predict if amino acid sequences contain an N-terminal transit peptide. Recently, ChloroP analysis and protoplast transient expression assays were used to identify a novel chloroplast targeting signal in the C-terminus of the chloroplast preprotein receptor Toc159 in Bienertia sinuspersici (Lung and Chuong, 2012). Toc159 was also shown to lack a canonical transmembrane domain typically present in OEPs. While the unique C-terminal targeting sequence has been partially characterized in Toc159 (Lung et al., 2014), it left open the question of whether this type of signal is unique to Toc159, or if it is used by other OEPs as well. In the current study, to determine if other OEPs use this novel targeting pathway, ChloroP analysis identified eight potential candidates possessing the putative C-terminal targeting signal in Arabidopsis. Transient protoplast expression assays have been performed on OEP18, the protein predicted with the highest ChloroP score, to determine its subcellular localization and the sequences required for its targeting to chloroplasts. The primary purpose of the current study was to establish whether chloroplast outer membrane proteins other than Toc159 use a similar C-terminal targeting signal. Overall, the data in this thesis suggest that some OEPs other than Toc159, such as OEP18, may use this novel targeting pathway

Composition of Light Solar Wind Noble Gases in the Bulk Metallic Glass flown on the Genesis Mission

We discuss data of light noble gases from the solar wind implanted into a metallic glass target flown on the Genesis mission. Helium and neon isotopic compositions of the bulk solar wind trapped in this target during 887 days of exposure to the solar wind do not deviate significantly from the values in foils of the Apollo Solar Wind Composition experiments, which have been exposed for hours to days. In general, the depth profile of the Ne isotopic composition is similar to those often found in lunar soils, and essentially very well reproduced by ion-implantation modelling, adopting the measured velocity distribution of solar particles during the Genesis exposure and assuming a uniform isotopic composition of solar wind neon. The results confirm that contributions from high-energy particles to the solar wind fluence are negligible, which is consistent with in-situ observations. This makes the enigmatic "SEP-Ne” component, apparently present in lunar grains at relatively large depth, obsolete. 20Ne/ 22Ne ratios in gas trapped very near the metallic glass surface are up to 10% higher than predicted by ion implantation simulations. We attribute this superficially trapped gas to very low-speed, current-sheet-related solar wind, which has been fractionated in the corona due to inefficient Coulomb dra

How have advances in genetic technology modified movement disorder nosology?

The role of genetics and its technological development have been fundamental in advancing the field of movement disorders, opening the door to precision medicine. Starting from the revolutionary discovery of the locus of the Huntington’s disease gene, we review the milestones of genetic discoveries in movement disorders and their impact on clinical practice and research efforts. Before the 1980s, early techniques did not allow the identification of genetic alteration in complex diseases. Further advances increasingly defined a large number of pathogenic genetic alterations. Moreover, these techniques allowed epigenomic, transcriptomic and microbiome analyses. In the 2020s, these new technologies are poised to displace phenotype-based classifications towards a nosology based on genetic/biological data. Advances in genetic technologies are engineering a reversal of the phenotype-to-genotype order of nosology development, replacing convergent clinicopathological disease models with the genotypic divergence required for future precision medicine applications.Fil: Sturchio, A.. University of Cincinnati; Estados UnidosFil: Marsili, L.. University of Cincinnati; Estados UnidosFil: Mahajan, A.. University of Cincinnati; Estados UnidosFil: Grimberg, M.B.. University of Cincinnati; Estados UnidosFil: Kauffman, Marcelo Andres. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Espay, A.J.. University of Cincinnati; Estados Unido

Noble gases in the NWA2737: a new chassignite signature

International audienceWe report noble gas data for the second chassignite, Northwest Africa (NWA) 2737, which was recently found in the Moroccan desert. The cosmic ray exposure (CRE) age based on cosmogenic 3He, 21Ne, and 38Ar around 10-11 Ma is comparable to the CRE ages of Chassigny and the nakhlites and indicates ejection of meteorites belonging to these two families during a discrete event, or a suite of discrete events having occurred in a restricted interval of time. In contrast, U-Th/He and K/Ar ages <0.5 Ga are in the range of radiometric ages of shergottites, despite a Sm-Nd signature comparable to that of Chassigny and the nakhlites (Misawa et al. 2005). Overall, the noble gas signature of NWA 2737 resembles that of shergottites rather than that of Chassigny and the nakhlites: NWA 2737 does not contain, in detectable amount, the solar-like xenon found in Chassigny and thought to characterize the Martian mantle nor apparently fission xenon from 244Pu, which is abundant in Chassigny and some of the nakhlites. In contrast, NWA 2737 contains Martian atmospheric noble gases trapped in amounts comparable to those found in shergottite impact glasses. The loss of Martian mantle noble gases, together with the trapping of Martian atmospheric gases, could have occurred during assimilation of Martian surface components, or more likely during shock metamorphism, which is recorded in the petrology of this meteorite

Transcriptional Regulation of Quinoa Seed Quality: Identification of Novel Candidate Genetic Markers for Increased Protein Content

Quinoa (Chenopodium quinoa Willd.) is a crop that has great potential for increased cultivation in diverse climate regions. The seed protein quality obtained from this crop is high concerning the requirements to meet human nutritional needs, but the seed protein content is relatively low if compared to crops such as grain legumes. Increased seed protein content is desirable for increasing the economic viability of this crop in order for it to be used as a protein crop. In this study, we characterized three genotypes of quinoa with different levels of seed protein content. By performing RNA sequencing of developing seeds, we determined the genotype differences in gene expression and identified genetic polymorphisms that could be associated with increased protein content. Storage nutrient analyses of seeds of three quinoa genotypes (Titicaca, Pasankalla, and Regalona) from different ecoregions grown under controlled climate conditions showed that Pasankalla had the highest protein content (20%) and the lowest starch content (46%). Our seed transcriptome analyses revealed highly differentially expressed transcripts (DETs) in Pasankalla as compared to the other genotypes. These DETs encoded functions in sugar transport, starch and protein synthesis, genes regulating embryo size, and seed transcription factors. We selected 60 genes that encode functions in the central carbon metabolism and transcription factors as potential targets for the development of high-precision markers. Genetic polymorphisms, such as single nucleotide polymorphisms (SNPs) and base insertions and deletions (InDels), were found in 19 of the 60 selected genes, which can be further evaluated for the development of genetic markers for high seed protein content in quinoa. Increased cultivation of quinoa can contribute to a more diversified agriculture and support the plant protein diet shift. The identification of quinoa genotypes with contrasting seed quality can help establish a model system that can be used for the identification of precise breeding targets to improve the seed quality of quinoa. The data presented in this study based on nutrient and transcriptome analyses contribute to an enhanced understanding of the genetic regulation of seed quality traits in quinoa and suggest high-precision candidate markers for such traits

El servicio de referencia ante la pandemia de COVID-19. Estudio de caso

The COVID-19 pandemic impacted the daily work of all citizens, especially in our libraries, since, after the Social, Preventive, and Mandatory Isolation (ASPO), in a short time, they were forced to adapt their activities so that they could be carried out remotely. In the case described, although a great impact on the operation of the library was expected, according to the statistics after one year, it was noted that, although the transactions had decreased, the usual activities had developed normally and its quality had not diminished thanks to the technological advantage of the institution in general and of the library's reference service in particular

El servicio de referencia ante la pandemia de COVID-19. Estudio de caso

The COVID-19 pandemic impacted the daily work of all citizens, especially in our libraries, since, after the Social, Preventive, and Mandatory Isolation (ASPO), in a short time, they were forced to adapt their activities so that they could be carried out remotely. In the case described, although a great impact on the operation of the library was expected, according to the statistics after one year, it was noted that, although the transactions had decreased, the usual activities had developed normally and its quality had not diminished thanks to the technological advantage of the institution in general and of the library's reference service in particular. &nbsp;La pandemia de COVID-19 impactó en el trabajo diario de todos los ciudadanos. Sobre todo en nuestras bibliotecas, dado que, a partir del Aislamiento Social, Preventivo y Obligatorio (ASPO), en poco tiempo, se vieron obligadas a adaptar sus actividades para que pudieran realizarse a distancia. En el caso que se describe a continuación, si bien se esperaba un gran impacto en el funcionamiento de la biblioteca, según las estadísticas luego de un año, se notó que, si bien las transacciones habían disminuido, las actividades habituales se habían desarrollado con normalidad y su calidad no había mermado debido a la ventaja tecnológica de la institución en general y del servicio de referencia de la biblioteca en particular

First DNA barcode reference library for the identification of South American freshwater fish from the lower Paraná river

Valid fish species identification is essential for biodiversity conservation and fisheries management. Here, we provide a sequence reference library based on mitochondrial cytochrome c oxidase subunit I for a valid identification of 79 freshwater fish species from the Lower Paraná River. Neighbour-joining analysis based on K2P genetic distances formed non-overlapping clusters for almost all species with a ≥99% bootstrap support each. Identification was successful for 97.8% of species as the minimum genetic distance to the nearest neighbour exceeded the maximum intraspecific distance in all these cases. A barcoding gap of 2.5% was apparent for the whole data set with the exception of four cases. Withinspecies distances ranged from 0.00% to 7.59%, while interspecific distances varied between 4.06% and 19.98%, without considering Odontesthes species with a minimum genetic distance of 0%. Sequence library validation was performed by applying BOLDs BIN analysis tool, Poisson Tree Processes model and Automatic Barcode Gap Discovery, along with a reliable taxonomic assignment by experts. Exhaustive revision of vouchers was performed when a conflicting assignment was detected after sequence analysis and BIN discordance evaluation. Thus, the sequence library presented here can be confidently used as a benchmark for identification of half of the fish species recorded for the Lower Paraná River.Instituto de Limnología "Dr. Raul A. Ringuelet

Enhanced detection of gametocytes by magnetic deposition microscopy predicts higher potential for Plasmodium falciparum transmission

<p>Abstract</p> <p>Background</p> <p>Aggregated haemozoin crystals within malaria-infected erythrocytes confer susceptibility of parasitized cells to a magnetic field. Here the utility of this method for diagnosis of human malaria is evaluated in a malaria-endemic region of Papua New Guinea (PNG).</p> <p>Methods and findings</p> <p>Individuals with <it>Plasmodium falciparum </it>malaria symptoms (n = 55) provided samples for conventional blood smear (CBS) and magnetic deposition microscopy (MDM) diagnosis. Standard Giemsa staining and light microscopy was performed to evaluate all preparations. <it>Plasmodium falciparum </it>parasitaemia observed on MDM slides was consistently higher than parasitaemia observed by (CBS) for ring (CBS = 2.6 vs. MDM = 3.4%; t-test P-value = 0.13), trophozoite (CBS = 0.5 vs. MDM = 1.6%; t-test P-value = 0.01), schizont (CBS = 0.003 vs. MDM = 0.1%; t-test P-value = 0.08) and gametocyte (CBS = 0.001 vs. MDM = 0.4%; t-test P-value = 0.0002) parasitaemias. Gametocyte prevalence determined by CBS compared to MDM increased from 7.3% to 45%, respectively.</p> <p>Conclusion</p> <p>MDM increased detection sensitivity of <it>P. falciparum</it>-infected, haemozoin-containing erythrocytes from infected humans while maintaining detection of ring-stage parasites. Gametocyte prevalence five-fold higher than observed by CBS suggests higher malaria transmission potential in PNG endemic sites compared to previous estimates.</p