1,775 research outputs found
Three-dimensional reconstruction of interstitial extracellular vesicles in human liver as determined by electron tomography
No full textExtracellular vesicles (EVs) are lipid bilayer nanoparticles involved in cell-cell communication that are released into the extracellular space by all cell types. The cargo of EVs includes proteins, lipids, nucleic acids, and metabolites reflecting their cell of origin. EVs have recently been isolated directly from solid tissues, and this may provide insights into how EVs mediate communication between cells in vivo. Even though EVs have been isolated from tissues, their point of origin when they are in the interstitial space has been uncertain. In this study, we performed three-dimensional (3D) reconstruction using transmission electron tomography of metastatic and normal liver tissues with a focus on the presence of EVs in the interstitium. After chemical fixation of the samples and subsequent embedding of tissue pieces in resin, ultrathin slices (300 nm) were cut and imaged on a 120 ekV transmission electron microscopy as a tilt series (a series of subsequent images tilted at different angles). These were then computationally illustrated in a 3D manner to reconstruct the imaged tissue volume. We identified the cells delimiting the interstitial space in both types of tissues, and small distinct spherical structures with a diameter of 30-200 nm were identified between the cells. These round structures appeared to be more abundant in metastatic tissue compared to normal tissue. We suggest that the observed spherical structures in the interstitium of the metastatic and non-metastatic liver represent EVs. This work thus provides the first 3D visualization of EVs in human tissue.Three-dimensional (3D) reconstruction of both liver metastases and normal liver, using transmission electron tomography, identified spherical structures with a diameter of 30-200 nm in the interstitium of both types of tissues.imag
The SPCA1 Ca2+ pump and intracellular membrane trafficking
No full textThe Golgi apparatus (GA) is a dynamic store of Ca that can be released into the cell cytosol. It can thus participate in the regulation of the Ca concentration in the cytosol ([Ca]), which might be critical for intra-Golgi transport. Secretory pathway Ca-ATPase pump type 1 (SPCA1) is important in Golgi homeostasis of Ca. The subcellular localization of SPCA1 appears to be GA specific, although its precise location within the GA is not known. Here, we show that SPCA1 is mostly excluded from the cores of the Golgi cisternae and is instead located mainly on the lateral rims of Golgi stacks, in tubular noncompact zones that interconnect different Golgi stacks, and within tubular parts of the trans Golgi network, suggesting a role in regulation of the local [Ca] that is crucial for membrane fusion. SPCA1 knockdown by RNA interference induces GA fragmentation. These Golgi fragments lack the cis-most and trans-most cisternae and remain within the perinuclear region. This SPCA1 knockdown inhibits exit of vesicular stomatitis virus G-protein from the GA and delays retrograde redistribution of the GA glycosylation enzymes into the endoplasmic reticulum caused by brefeldin A; however, exit of these enzymes from the endoplasmic reticulum is not affected. Thus, correct SPCA1 functioning is crucial to intra-Golgi transport and maintenance of the Golgi ribbon
Recuerdos de Massimo.
No full textEl presente ensayo recuerda la rica relación personal e intelectual entre Massimo Pavarini e Iñaki Rivera Beiras desde que el segundo conoció siendo muy joven a Pavarini. En ese sentido, el trabajo recuerda los inicios de su fecunda relación en la ciudad de Bologna cuando Iñaki Rivera acudía a presentar a Massimo Pavarini los desarrollos de lo que sería su tesis doctoral. Las contribuciones de Pavarini al proceso de aprendizaje de Rivera, en el terreno de una epistemología crítica en la penología contemporánea, son analizados como un homenaje a la memoria y a la obra del autor italiano, tras su fallecimiento en septiembre de 2015.This paper recalls the rich personal and intellectual relationship between Massimo Pavarini and Iñaki Rivera Beiras. In that sense , the work recalls the beginning of his fruitful relationship in the city of Bologna when Iñaki Rivera came to present Massimo Pavarini’ developments in what would be his PhD thesis. Pavarini contributions to the learning process of Rivera, on the ground of a critical epistemology in contemporary penology , are analyzed as a tribute to the memory and to the work of Italian author, after his death in September 2015 .El presente ensayo recuerda la rica relación personal e intelectual entre Massimo Pavarini e Iñaki Rivera Beiras desde que el segundo conoció siendo muy joven a Pavarini. En ese sentido, el trabajo recuerda los inicios de su fecunda relación en la ciudad de Bologna cuando Iñaki Rivera acudía a presentar a Massimo Pavarini los desarrollos de lo que sería su tesis doctoral. Las contribuciones de Pavarini al proceso de aprendizaje de Rivera, en el terreno de una epistemología crítica en la penología contemporánea, son analizados como un homenaje a la memoria y a la obra del autor italiano, tras su fallecimiento en septiembre de 2015
Selenite biotransformation and detoxification by Stenotrophomonas maltophilia SeITE02: Novel clues on the route to bacterial biogenesis of selenium nanoparticles
No full textA putative biosynthetic mechanism for selenium nanoparticles (SeNPs) and efficient reduction of selenite (SeO32-) in the bacterial strain Stenotrophomonas maltophilia SeITE02 are addressed here on the basis of information gained by a combined approach relying on a set of physiological, chemical/biochemical, microscopy, and proteomic analyses. S. maltophilia SeITE02 is demonstrated to efficiently transform selenite into elemental selenium (Se°) by reducing 100% of 0.5mM of this toxic oxyanion to Se° nanoparticles within 48h growth, in liquid medium. Since the selenite reducing activity was detected in the cytoplasmic protein fraction, while biogenic SeNPs showed mainly extracellular localization, a releasing mechanism of SeNPs from the intracellular environment is hypothesized. SeNPs appeared spherical in shape and with size ranging from 160nm to 250nm, depending on the age of the cultures. Proteomic analysis carried out on the cytoplasmic fraction identified an alcohol dehydrogenase homolog, conceivably correlated with the biogenesis of SeNPs. Finally, by Fourier Transformed Infrared Spectrometry, protein and lipid residues were detected on the surface of biogenic SeNPs. Eventually, this strain might be efficaciously exploited for the remediation of selenite-contaminated environmental matrices due to its high SeO32- reducing efficiency. Biogenic SeNPs may also be considered for technological applications in different fields
Predoni a casa nostra e il geografo solidale: Massimo Quaini tra terra e acqua
No full textIn accordance with the main goals of this collection of essays in honour of Massimo Quaini, the text focuses on a peculiar character of the Ligurian geographer’s sensibility, his attention to landscape protectionresearch activity developed in the context of the humanistic geography. Starting from a personal narrative based on his own reminiscences and neglected memories, the author tries to shed light on the relationships between civil commitment and cultural reflection which characterize environmental sensitivity, bringing together his interests with Quaini’s emotional geographies. Finally, some of Quaini’s everyday practicalities are highlighted as the easiest doorway to improve the cognitive procedures of cultural geography
Is Felix Salten the author of the Mutzenbacher novel (1906)? Yes and no
No full textJosefine Mutzenbacher oder die Geschichte einer Wienerischen Dirne von ihr selbst erzählt, published in Vienna in 1906, represents one of the most fascinating cases of attribution of authorship in German literature. Although Josefine Mutzenbacher is usually attributed to Felix Salten, the author of the world-famous Bambi (1923), the novel’s authorship has never been confirmed, and many other candidates have been named as potential authors. Among them is Arthur Schnitzler, who published Reigen, a cycle of amorous adventures in Viennese society, in 1903. Some scholars, instead, have attributed the novel to such lesser-known writers as Ernst Klein and Willi Handl. The controversy surrounding the authorship of Josefine Mutzenbacher was the starting point for our stylometric analyses, and our results help to answer some unresolved questions in a debate that has lasted for more than 100 years. The analyses were performed using the R package Stylo, which enables an efficient application of Burrows’ Delta and its variants. Focusing on both the entire text and on the final pages, two different types of analysis were carried out: one combines 1200 different stylometric methods to compare the candidate authors Salten, Schnitzler, Bahr, Altenberg, Hofmannsthal, Klein and Handl; the other verifies the attribution using the ‘impostors’ method. The results show that the most probable author is Felix Salten, while none of the candidates could be identified as the author of the final pages, confirming the hypothesis that the text was left unfinished by Salten and completed by an as-yet-unidentified ghost-writer
Plastid Genotyping Reveals the Uniformity of Cytoplasmic Male Sterile-T Maize Cytoplasms
No full textCytoplasmic male-sterile (CMS) lines in maize (Zea mays) have been classified by their response to specific restorer genes into three categories: cms-C, cms-S, and cms-T. A mitochondrial genome representing each of the CMS cytotypes has been sequenced, and male sterility in the cms-S and cms-T cytotypes is linked to chimeric mitochondrial genes. To identify markers for plastid genotyping, we sequenced the plastid genomes of three fertile maize lines (B37, B73, and A188) and the B37 cms-C, cms-S, and cms-T cytoplasmic substitution lines. We found that the plastid genomes of B37 and B73 lines are identical. Furthermore, the fertile and CMS plastid genomes are conserved, differing only by zero to three single-nucleotide polymorphisms (SNPs) in coding regions and by eight to 22 SNPs and 10 to 21 short insertions/deletions in noncoding regions. To gain insight into the origin and transmission of the cms-T trait, we identified three SNPs unique to the cms-T plastids and tested the three diagnostic SNPs in 27 cms-T lines, representing the HA, I, Q, RS, and T male-sterile cytoplasms. We report that each of the tested 27 cms-T group accessions have the same three diagnostic plastid SNPs, indicating a single origin and maternal cotransmission of the cms-T mitochondria and plastids to the seed progeny. Our data exclude exceptional pollen transmission of organelles or multiple horizontal gene transfer events as the source of the mitochondrial urf13-T (unidentified reading frame encoding 13-kD cms-T protein) gene in the cms-T cytoplasms. Plastid genotyping enables a reassessment of the evolutionary relationships of cytoplasms in cultivated maize.Peer reviewe
A cidade, de Massimo Cacciari
No full textThis review presents a summary of the series of seminars presented by Massimo Cacciari at the Centro Sant´Apollinare de Fiesole, transcribed and edited by Tonino Rasuto. The work, entitled The city, brings reflections on what the author understands as the origin of urban configurations, more precisely what he classifies as the post-metropolis, the city-territory, which has its formation linked to the principles of Greek polis and of the Roman civitas. Finally, the author defines the potential of place and the geography of events, based on a methodological path of understanding the phenomena that were able to reframe the meaning of the city for the human being.Apresenta-se nesta resenha, uma síntese da série de seminários apresentados por Massimo Cacciari no Centro Sant´Apollinare de Fiesole, transcrita e editada por Tonino Rasuto. A obra, de título A cidade, traz reflexões acerca do que o autor entende como a origem das configurações urbanas, mais precisamente o que classifica como a pós-metrópole, a cidade-território, que tem sua formação ligada aos princípios da pólis grega e da civitas romana. Por fim, o autor define o potencial de lugar e da geografia de acontecimentos, a partir de um caminho metodológico de entendimentos dos fenômenos que foram capazes de ressignificar o sentido de cidade para o ser humano
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