Pyrene lipids as markers of peroxidative processes in different regions of low and high density lipoproteins

AbstractThree different pyrene derivatives, pyrene decanoyl phosphatidylcholine (P10PC), pyrene dodecanoyl sulfatide (P12CS) and cholesteryl pyrenyl hexanoate (P6Chol), were used to follow lipid peroxidation in low and high density lipoproteins. Probe-labelled lipoproteins were subjected to Cu2+ catalyzed peroxidation. In all cases the fluorescence of the probes progressively decreased due to the involvement of pyrene in the peroxidative reaction. Thus, we used the fluorescence decrease of P6Chol to monitor the lipid peroxidation in the hydrophobic core of LDL and HDL, and that of the amphipatic probes, P10PC and P12CS, to follow lipid peroxidation in the envelope of both lipoproteins. The possibility of following lipid peroxidation in individual lipoprotein regions could lead to more detailed information on the oxidative modifications that play an important role in the altered cholesterol homeostasis involved in the formation of atherosclerotic lesions. No differences were observed in the peroxidation kinetics of the hydrophobic core of HDL and LDL monitored with P6Chol. On the contrary kinetics obtained with P10PC and P12CS demonstrated the HDL envelope to be more susceptible to Cu2+-dependent lipid peroxidation than that of the LDL. This could be due to a greater radical generating capacity of the HDL envelope and can be explained on the basis of low vitamin E levels and large amounts of polyunsaturated fatty acids esterified on phospholipids determined in HDL, and on literature evidence that indicates HDL as the principal vehicle of circulating plasma lipid peroxides

Integrating single cell transcriptomics and volume electron microscopy confirms the presence of pancreatic acinar-like cells in sea urchins

The identity and function of a given cell type relies on the differential expression of gene batteries that promote diverse phenotypes and functional specificities. Therefore, the identification of the molecular and morphological fingerprints of cell types across taxa is essential for untangling their evolution. Here we use a multidisciplinary approach to identify the molecular and morphological features of an exocrine, pancreas-like cell type harbored within the sea urchin larval gut. Using single cell transcriptomics, we identify various cell populations with a pancreatic-like molecular fingerprint that are enriched within the S. purpuratus larva digestive tract. Among these, in the region where they reside, the midgut/stomach domain, we find that populations of exocrine pancreas-like cells have a unique regulatory wiring distinct from the rest the of the cell types of the same region. Furthermore, Serial Block-face scanning Electron Microscopy (SBEM) of the exocrine cells shows that this reported molecular diversity is associated to distinct morphological features that reflect the physiological and functional properties of this cell type. Therefore, we propose that these sea urchin exocrine cells are homologous to the well-known mammalian pancreatic acinar cells and thus we trace the origin of this particular cell type to the time of deuterostome diversification. Overall, our approach allows a thorough characterization of a complex cell type and shows how both the transcriptomic and morphological information contribute to disentangling the evolution of cell types and organs such as the pancreatic cells and pancreas. Keywords: SBEM; acinar cells; evolution of cell types; morphology; pancreas; scRNAseq; sea urchin

Whole animal freeze-fracture scanning electron microscopy: an easy-to-use method to investigate cell type morphology of marine embryos and larvae

Morphological and molecular characterization of cell types, organs and individual organisms is essential for understanding the origins of morphogenesis. The increased implementation of high throughput methods as a means to address cell type evolution, during the last decade, created the need for an efficient way to assess cell type morphology. Here in order to create a new tool to study cell type morphology, we optimized a fast and easy-to-use whole animal freeze-fracture scanning electron microscopy (WAFFSEM) method. This method was applied on marine experimental systems (echinoderms, mollusks, tunicates, and cephalochordates), that have been widely used to assess environmental, developmental, and evolutionary questions. Our protocol does not require any specialized equipment and the processed specimens are compatible with scanning electron microscopy. This protocol was able to successfully expose the internal cell types of all specimens in which it was tested and to reveal their cellular and subcellular characteristics. We strongly believe that the combination of our protocol with other methods (e.g., light microscopy and single cell transcriptomics) will be beneficial to further improve the way to classify and describe cell types

A novel member of the BTB/POZ family, PATZ, associates with the RNF4 RING finger protein and acts as a transcriptional repressor.

We have identified a novel human gene encoding a 59-kDa POZ-AT hook-zinc finger protein (PATZ) that interacts with RNF4, a mediator of androgen receptor activity, and acts as a transcriptional repressor. PATZ cDNA was isolated through a two-hybrid interaction screening using the RING finger protein RNF4 as a bait. In vitro and in vivo interaction between RNF4 and PATZ was demonstrated by protein-protein affinity chromatography and coimmunoprecipitation experiments. Such interaction occurred through a small region of PATZ containing an AT-hook DNA binding domain. Immunofluorescence staining and confocal microscopy showed that PATZ localizes in distinct punctate nuclear regions and colocalizes with RNF4. Functional analysis was performed by cotransfection assays: PATZ acted as a transcriptional repressor, whereas its partner RNF4 behaved as a transcriptional activator. When both proteins were overexpressed a strong repression of the basal transcription was observed, indicating that the association of PATZ with RNF4 switches activation to repression. In addition, RNF4 was also found to associate with HMGI(Y), a chromatin-modeling factor containing AT-hook domains

The ability of lumbar spine DXA and phalanx QUS to detect previous fractures in young thalassemic patients with hypogonadism, hypothyroidism, diabetes, and hepatitis-B: A 2-year subgroup analysis from the Taranto Area of Apulia Region.

BACKGROUND: Osteoporosis is a leading cause of morbidity in patients affected by β-thalassemia major or intermediate; we aimed to assess the association between demineralization observed in young thalassemic patients. METHODS: A total of 88 patients with β-thalassemia were recruited at Microcitemia Center of Taranto Hospital under the Prevention Osteoporosis and Fractures research project from 2008 to 2010. All the patients were screened with both dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS). T score and Z score values were obtained for each subject. RESULTS: The overall prevalence of demineralization was 84% with DXA and 70% with QUS, whereas normality was found in 16% of patients screened with DXA and in 30% of cases with QUS. Hypogonadism, hypothyroidism, diabetes mellitus, hepatitis-B, and the presence of previous fragility fractures were significantly associated with the demineralization status (lower T scores values) both with DXA and QUS. CONCLUSION: Our data confirm that DXA and QUS examinations are both useful for detecting bone demineralization in thalassemic patients

Evolution of the ribbon-like organization of the Golgi apparatus in animal cells

The ‘‘ribbon,’’ a structural arrangement in which Golgi stacks connect to each other, is considered to be restricted to vertebrate cells. Although ribbon disruption is linked to various human pathologies, its functional role in cellular processes remains unclear. In this study, we investigate the evolutionary origin of the Golgi ribbon. We observe a ribbon-like architecture in the cells of several metazoan taxa suggesting its early emergence in animal evolution predating the appearance of vertebrates. Supported by AlphaFold2 modeling, we propose that the evolution of Golgi reassembly and stacking protein (GRASP) binding by golgin tethers may have driven the joining of Golgi stacks resulting in the ribbon-like configuration. Additionally, we find that Golgi ribbon assembly is a shared developmental feature of deuterostomes, implying a role in embryogenesis. Overall, our study points to the functional significance of the Golgi ribbon beyond vertebrates and underscores the need for further investigations to unravel its elusive biological roles

Inclusión social y Universidades. El Máster en Ayudante/Facilitador independencia y la comunicación de las personas con discapacidad visual y auditiva. Un proyecto de formación de postgrado

La Universidad de Roma "La Sapienza " promueve cursos institucionales de perfecion científica y de alta formacion , en colaboración con otras universidades, organismos y entidades públicas y privadas , tales como la conclusión de la obtención del título de Máster I y Nivel II . Estos cursos integran la oferta educativa de la Universidad y están registradas en la base de datos , patrocinado por el Ministerio de Educación a través de la CINECA . El Maestro se describe aquí se pretende contribuir a la formación de profesionales especializados para trabajar hacia la inclusión social de las personas con discapacidades sensoriales en los entornos educativos . Nuestra iniciativa tiene como objetivo la formación y cualificación de los profesionales requeridos por las leyes y peticiones fuertemente de la sociedad civil. El asistente se destaca como un operador socio- educativa con la función principal de " mediación " y "facilitar" los contextos y formas de comunicación , el aprendizaje , la relación y la integración de las personas con discapacidades específicas . Para ello, este profesional debe poseer y finalizar múltiples habilidades , estrategias de enseñanza , materiales y recursos específicos de equipos para mejorar los procesos de inclusión y calidad de vida en diversos ámbitos de la vida civil. La universidad, con cursos específicos de formación como el Máster propuesto, se ofrece como una herramienta de formación y profesionalización , la participación en la promoción de la plena aplicación de los derechos de las personas y las perspectivas de la cohesión social y la inclusión de una sociedad democrática

The Photomorphogenesis Regulator DET1 Binds the Amino-Terminal Tail of Histone H2B in a Nucleosome Context

AbstractLight provides a major source of information from the environment during plant growth and development [1, 2]. Recent results suggest that the key events controlling light-regulated gene expression in plants are translocation of the phytochrome photoreceptors into the nucleus, followed by their binding to transcription factors such as PIF3. Coupled with this, the degradation of positively acting intermediates such as the transcription factor HY5 by COP1 and the COP9 signalosome appears to be an important process whereby photomorphogenesis is repressed in darkness (e.g., [3–8]). Genetic analyses in Arabidopsis and tomato have revealed that the nuclear protein DET1 also plays a key role in the repression of photomorphogenesis [9–11]. However, the function of this protein has remained a mystery. In a series of in vitro experiments, we provide persuasive evidence that DET1 binds to nonacetylated amino-terminal tails of the core histone H2B in the context of the nucleosome. Furthermore, we have utilized FRET (fluorescence resonance energy transfer) imaging with GFP variants to demonstrate this interaction within the nucleus of living plant cells. Given the dramatic photomorphogenic phenotypes of det1 mutants, we propose that chromatin remodeling [12–14] plays a heretofore unsuspected role in regulating gene expression during photomorphogenesis

E. coli as a Model for the Description of the Antimicrobial Mechanism of a Cationic Polymer Surface: Cellular Target and Bacterial Contrast Response

In this study we use E. coli as a model to investigate the antimicrobial mechanism of a film made of a copolymer based on mPEG, MMA and DMAEMA and whose surface is active towards Gram-negative and Gram-positive bacteria. The polymer contains not quaternized amino groups able to generate a charged surface by protonation when in contact with water. For the purpose, we adopted a dual strategy based on the analysis of cell damage caused by contact with the polymer surface, and on the evaluation of the cell response to the surface toxic action. The lithic effect on the protoplasts of E. coli showed that polymer surface can affect the structure of cytoplasmic membranes while assays of calcein leakage from LUVs at different phospholipids composition indicated that action on membranes does not need a functionally active cell. On the other hand, the significant increase in sensitivity to actinomycin D demonstrates that polymer interferes also with the structure of the outer membrane, modifying its permeability. The study on gene expression, based on the analysis of the transcripts in a temporal window where the contact with the polymer is not lethal and the damage is reversible, showed that some key genes of the synthesis and maintenance of OM structure (fabR, fadR, fabA, waaA, waaC, kdsA, pldA, pagP), as well as regulators of cellular response to oxidative stress (soxS), are more expressed when bacteria are exposed to polymer surface. All together these results identified the outer membrane as the main cellular target of antimicrobial surface and indicated a specific cellular response to damage, providing more information on the antimicrobial mechanism. In perspective, data here reported could play a pivotal role in a microbial growth control strategy based not only on the structural improvements of the materials, but also on the possibility of intervening on the cellular pathways involved in the contrast reaction to these and other polymers with similar mechanisms