Intracellular Parasite Toxoplasma Exploits the Unfolded Protein Response to Acquire Mitochondrial Metabolites

Toxoplasma gondii is an obligate intracellular parasite that reconfigures its host cell to promote pathogenesis. Toxoplasma is able to infect virtually all warm-blooded animals, and it is estimated that this parasite has infected nearly 2 billion people globally and approximately 25% of the US population. Curiously, upon infection Toxoplasma recruits the host cell’s endoplasmic reticulum (ER) and mitochondria into close proximity to the parasitophorous vacuole (PV), although the reasons for these high affinity interactions are not completely understood. It has been shown that Toxoplasma induces host mitochondria elongation to acquire fatty acids and establish a niche for itself. Our exciting new data showed that through the host ER-PV association, Toxoplasma actively induces the unfolded protein response (UPR), leading to PERK activation. Furthermore, new data suggests that PERK activation coordinates mitochondrial elongation. Therefore, we hypothesize that PERK activation induces mitochondrial elongation in Toxoplasma infected cells. Using immunofluorescence, we determined whether PERK activation plays a role in mitochondrial elongation induced by Toxoplasma infection. First, we confirmed that the Toxoplasma PV interacts with host mitochondria and ER. Next, we found that Toxoplasma infection promotes mitochondrial elongation and by using a pharmacological approach, we were able to inhibit PERK, which significantly decreased mitochondrial elongation. Our study has identified a novel mechanism used by Toxoplasma to induce mitochondrial elongation in order to acquire fatty acids, providing new insights into strategies for treatment of toxoplasmosis.https://digitalcommons.unmc.edu/surp2022/1000/thumbnail.jp

Automated tracing of myelinated axons and detection of the nodes of Ranvier in serial images of peripheral nerves

The development of realistic neuroanatomical models of peripheral nerves for simulation purposes requires the reconstruction of the morphology of the myelinated fibres in the nerve, including their nodes of Ranvier. Currently, this information has to be extracted by semimanual procedures, which severely limit the scalability of the experiments. In this contribution, we propose a supervised machine learning approach for the detailed reconstruction of the geometry of fibres inside a peripheral nerve based on its high-resolution serial section images. Learning from sparse expert annotations, the algorithm traces myelinated axons, even across the nodes of Ranvier. The latter are detected automatically. The approach is based on classifying the myelinated membranes in a supervised fashion, closing the membrane gaps by solving an assignment problem, and classifying the closed gaps for the nodes of Ranvier detection. The algorithm has been validated on two very different datasets: (i) rat vagus nerve subvolume, SBFSEM microscope, 200 × 200 × 200 nm resolution, (ii) rat sensory branch subvolume, confocal microscope, 384 × 384 × 800 nm resolution. For the first dataset, the algorithm correctly reconstructed 88% of the axons (241 out of 273) and achieved 92% accuracy on the task of Ranvier node detection. For the second dataset, the gap closing algorithm correctly closed 96.2% of the gaps, and 55% of axons were reconstructed correctly through the whole volume. On both datasets, training the algorithm on a small data subset and applying it to the full dataset takes a fraction of the time required by the currently used semiautomated protocols. Our software, raw data and ground truth annotations are available at http://hci.iwr.uni-heidelberg.de/Benchmarks/. The development version of the code can be found at https://github.com/RWalecki/ATMA

CAN NLR BE A BIOMARKER FOR MUCOSITIS AND GVHD IN PATIENTS UNDERGOING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION?

Allogeneic hematopoietic stem cell transplantation (HSCT) is the treatment for many diseases, however can induce important complications such as Oral Mucositis (OM) and Graft-versus-Host Disease (GVHD). The neutrophil-lymphocyte ratio (NLR) is a peripheral biomarker of systemic inflammation and an independent prognostic factor in several inflammatory diseases. Objective: The aim of this study was to evaluate the association of NLR with OM and GVHD in patients undergoing allogeneic HSCT. Methods: Patients who underwent  allogeneic HSCT at the Bone Marrow Transplant Service at the Hospital de Clínicas Complex of the Federal University of Paraná were included in the study. Sociodemographic data and blood count were collected from patients' medical records. NLR was calculated and associated with OM and GVHD. Results: 45 patients were included in the study. NLR was considerably higher in patients who had OM and oral GVHD when compared to patients who did not present these conditions, nonetheless no statistically significant difference was observed. Conclusion: Although both OM and GVHD are associated with inflammatory response as well as to the immune system, it was not associated with NLR. A further investigation considering other variables related to the HSCT might find possible association as it could favor patients management and prevention

Microbial Fouling of a Reverse Osmosis Municipal Water Treatment System

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146838/1/wer0703.pd

O ATUAL CENÁRIO PENITENCIÁRIO BRASILEIRO: DESCASO E ABANDONO DA FUNÇÃO REABILITADORA

A política criminal brasileira apresenta à população a imagem de que o sistema penitenciário está de acordo com as diretrizes humanitárias e respeita princípios como o da dignidade da pessoa humana. A ideia de recuperação foi, assim, inserida ao ideal de punição e fez com que a finalidade da pena privativa de liberdade possuísse um duplo caráter (retributivo e reformador). Esse conceito criou raízes no imaginário da sociedade contemporânea, entretanto o aumento constante e significativo da população carcerária e a realidade dos estabelecimentos demonstra o oposto. Desse modo, por meio de uma pesquisa qualitativa bibliográfica e documental, usando-se de literatura e de dados estatísticos, pretende-se demonstrar algumas questões da realidade carcerária brasileira e como a reabilitação não ocorre no sistema penitenciário brasileiro, uma vez que o seu conceito não mais se aplica na formação social atual

CD20 and CD19 targeted vectors induce minimal activation of resting B lymphocytes

B lymphocytes are an important cell population of the immune system. However, until recently it was not possible to transduce resting B lymphocytes with retro- or lentiviral vectors, making them unsusceptible for genetic manipulations by these vectors. Lately, we demonstrated that lentiviral vectors pseudotyped with modified measles virus (MV) glycoproteins hemagglutinin, responsible for receptor recognition, and fusion protein were able to overcome this transduction block. They use either the natural MV receptors, CD46 and signaling lymphocyte activation molecule (SLAM), for cell entry (MV-LV) or the vector particles were further modified to selectively enter via the CD20 molecule, which is exclusively expressed on B lymphocytes (CD20-LV). It has been shown previously that transduction by MV-LV does not induce B lymphocyte activation. However, if this is also true for CD20-LV is still unknown. Here, we generated a vector specific for another B lymphocyte marker, CD19, and compared its ability to transduce resting B lymphocytes with CD20-LV. The vector (CD19ds-LV) was able to stably transduce unstimulated B lymphocytes, albeit with a reduced efficiency of about 10% compared to CD20-LV, which transduced about 30% of the cells. Since CD20 as well as CD19 are closely linked to the B lymphocyte activation pathway, we investigated if engagement of CD20 or CD19 molecules by the vector particles induces activating stimuli in resting B lymphocytes. Although, activation of B lymphocytes often involves calcium influx, we did not detect elevated calcium levels. However, the activation marker CD71 was substantially up-regulated upon CD20-LV transduction and most importantly, B lymphocytes transduced with CD20-LV or CD19ds-LV entered the G1b phase of cell cycle, whereas untransduced or MV-LV transduced B lymphocytes remained in G0. Hence, CD20 and CD19 targeting vectors induce activating stimuli in resting B lymphocytes, which most likely renders them susceptible for lentiviral vector transduction

Disposition of Federally Owned Surpluses

PDZ domains are scaffolding modules in protein-protein interactions that mediate numerous physiological functions by interacting canonically with the C-terminus or non-canonically with an internal motif of protein ligands. A conserved carboxylate-binding site in the PDZ domain facilitates binding via backbone hydrogen bonds; however, little is known about the role of these hydrogen bonds due to experimental challenges with backbone mutations. Here we address this interaction by generating semisynthetic PDZ domains containing backbone amide-to-ester mutations and evaluating the importance of individual hydrogen bonds for ligand binding. We observe substantial and differential effects upon amide-to-ester mutation in PDZ2 of postsynaptic density protein 95 and other PDZ domains, suggesting that hydrogen bonding at the carboxylate-binding site contributes to both affinity and selectivity. In particular, the hydrogen-bonding pattern is surprisingly different between the non-canonical and canonical interaction. Our data provide a detailed understanding of the role of hydrogen bonds in protein-protein interactions

Revisiting the Local Structure in Ge-Sb-Te based Chalcogenide Superlattices.

The technological success of phase-change materials in the field of data storage and functional systems stems from their distinctive electronic and structural peculiarities on the nanoscale. Recently, superlattice structures have been demonstrated to dramatically improve the optical and electrical performances of these chalcogenide based phase-change materials. In this perspective, unravelling the atomistic structure that originates the improvements in switching time and switching energy is paramount in order to design nanoscale structures with even enhanced functional properties. This study reveals a high- resolution atomistic insight of the [GeTe/Sb2Te3] interfacial structure by means of Extended X-Ray Absorption Fine Structure spectroscopy and Transmission Electron Microscopy. Based on our results we propose a consistent novel structure for this kind of chalcogenide superlattices