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Found 37769 matches. Displaying 1431-1440
Johnson DS, Deneau T, Toledo-Crow R, Simon SM
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Microscope Enclosure for Temperature Regulation and Light Isolation

APPLIED SCIENCES-BASEL 2021 AUG; 11(15):? Article 6812
Featured Application Here we present the design of a temperature regulation and light isolation microscope enclosure. This design can be readily adapted to the specific configurations of a custom imaging system. Light isolation and temperature regulation are often required for microscopic imaging. Commercial enclosures are available to satisfy these requirements, but they are often not flexible to the variety of custom systems found in research laboratories. We present the design for an affordable enclosure which utilizes aluminum t-slot profiles to support opaque expanded PVC panels. Temperature is regulated by exchanging the enclosure air with an external heater. In addition, we demonstrate baffles integrated into the enclosure improve temperature uniformity. Example designs for both upright and inverted microscopes are given, providing a starting point for creating a system-specific custom enclosure.
Zhou W, Melamed D, Banyai G, Meyer C, Tuschl T, Wickens M, Cao JY, Fields S
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Expanding the binding specificity for RNA recognition by a PUF domain

NATURE COMMUNICATIONS 2021 AUG 24; 12(1):? Article 5107
The PUF RNAbinding domain has an eight-repeat structure with the ability to bind an eight-base RNA sequence. Here the authors generate a comprehensive library of variants of a PUF domain to find an RNA binding code and design PUF domains that recognize an arbitrary RNA sequence. The ability to design a protein to bind specifically to a target RNA enables numerous applications, with the modular architecture of the PUF domain lending itself to new RNA-binding specificities. For each repeat of the Pumilio-1 PUF domain, we generate a library that contains the 8,000 possible combinations of amino acid substitutions at residues critical for RNA contact. We carry out yeast three-hybrid selections with each library against the RNA recognition sequence for Pumilio-1, with any possible base present at the position recognized by the randomized repeat. We use sequencing to score the binding of each variant, identifying many variants with highly repeat-specific interactions. From these data, we generate an RNA binding code specific to each repeat and base. We use this code to design PUF domains against 16 RNAs, and find that some of these domains recognize RNAs with two, three or four changes from the wild type sequence.
Trible W, Kronauer DJC
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Ant caste evo-devo: size predicts caste (almost) perfectly

TRENDS IN ECOLOGY & EVOLUTION 2021 AUG; 36(8):671-673
Yang R, Weisshaar M, Mele F, Benhsaien I, Dorgham K, Han J, Croft CA, Notarbartolo S, Rosain J, Bastard P, Puel A, Fleckenstein B, Glimcher LH, Di Santo JP, Ma CS, Gorochov G, Bousfiha A, Abel L, Tangye SG, Casanova JL, Bustamante J, Sallusto F
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High Th2 cytokine levels and upper airway inflammation in human inherited T-bet deficiency

JOURNAL OF EXPERIMENTAL MEDICINE 2021 AUG 2; 218(8):? Article e20202726
We have described a child suffering from Mendelian susceptibility to mycobacterial disease (MSMD) due to autosomal recessive, complete T-bet deficiency, which impairs IFN-gamma production by innate and innate-like adaptive, but not mycobacterial-reactive purely adaptive, lymphocytes. Here, we explore the persistent upper airway inflammation (UAI) and blood eosinophilia of this patient. Unlike wild-type (WT) T-bet, the mutant form of T-bet from this patient did not inhibit the production of Th2 cytokines, including IL-4, IL-5, IL-9, and IL-13, when overexpressed in T helper 2 (Th2) cells. Moreover, Herpesvirus saimiri-immortalized T cells from the patient produced abnormally large amounts of Th2 cytokines, and the patient had markedly high plasma IL-5 and IL-13 concentrations. Finally, the patient's CD4(+) alpha beta T cells produced most of the Th2 cytokines in response to chronic stimulation, regardless of their antigen specificities, a phenotype reversed by the expression of WT T-bet. T-bet deficiency thus underlies the excessive production of Th2 cytokines, particularly IL-5 and IL-13, by CD4(+) alpha beta T cells, causing blood eosinophilia and UAI. The MSMD of this patient results from defective IFN-. production by innate and innate-like adaptive lymphocytes, whereas the UAI and eosinophilia result from excessive Th2 cytokine production by adaptive CD4(+) alpha beta T lymphocytes.
Li XL, Fetter R, Schwabe T, Jung C, Liu LR, Steller H, Gaul U
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The cAMP effector PKA mediates Moody GPCR signaling in Drosophila blood-brain barrier formation and maturation

ELIFE 2021 AUG 12; 10(?):? Article e68275
The blood-brain barrier (BBB) of Drosophila comprises a thin epithelial layer of subperineural glia (SPG), which ensheath the nerve cord and insulate it against the potassium-rich hemolymph by forming intercellular septate junctions (SJs). Previously, we identified a novel Gi/Go protein-coupled receptor (GPCR), Moody, as a key factor in BBB formation at the embryonic stage. However, the molecular and cellular mechanisms of Moody signaling in BBB formation and maturation remain unclear. Here, we identify cAMP-dependent protein kinase A (PKA) as a crucial antagonistic Moody effector that is required for the formation, as well as for the continued SPG growth and BBB maintenance in the larva and adult stage. We show that PKA is enriched at the basal side of the SPG cell and that this polarized activity of the Moody/PKA pathway finely tunes the enormous cell growth and BBB integrity. Moody/PKA signaling precisely regulates the actomyosin contractility, vesicle trafficking, and the proper SJ organization in a highly coordinated spatiotemporal manner. These effects are mediated in part by PKA's molecular targets MLCK and Rho1. Moreover, 3D reconstruction of SJ ultrastructure demonstrates that the continuity of individual SJ segments, and not their total length, is crucial for generating a proper paracellular seal. Based on these findings, we propose that polarized Moody/PKA signaling plays a central role in controlling the cell growth and maintaining BBB integrity during the continuous morphogenesis of the SPG secondary epithelium, which is critical to maintain tissue size and brain homeostasis during organogenesis.
Bor WL, Zheng KL, Tavenier AH, Gibson CM, Granger CB, Bentur O, Lobatto R, Postma S, Coller BS, van 't Hof AWJ, Ten Berg JM
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Pharmacokinetics, pharmacodynamics, and tolerability of subcutaneous administration of a novel glycoprotein IIb/IIIa inhibitor, RUC-4, in patients with ST-segment elevation myocardial infarction

EUROINTERVENTION 2021 AUG; 17(5):E401-410
Background: Pre-hospital platelet inhibition in patients with ST-segment elevation myocardial infarction (STEMI) may improve outcomes. RUC-4 is a novel, second-generation glycoprotein IIb/IIIa inhibitor designed for first-point-of-medical-contact treatment for STEMI by subcutaneous injection. Aims: The open-label, phase 2A, CEL-02 trial aimed to assess the pharmacodynamics (PD), pharmacokinetics (PK), and tolerability of RUC-4 in STEMI patients undergoing primary PCI (pPCI). Methods: A total of 27 STEMI patients received a weight-adjusted subcutaneous injection of RUC-4 before pPCI in escalating doses (0.075 mg/kg [n = 8], 0.090 mg/kg [n = 9], or 0.110 mg/kg [n = 10]). Results: The primary PD endpoint of high-grade (>= 77%) inhibition of the VerifyNow iso-TRAP assay at 15 minutes was met in 3/8, 7/8, and 7/8 patients in the three cohorts with a dose-response relationship (mean inhibition [min -max] of 77.5% [65.7%-90.6%], 87.5% [73.8%-93.1%], and 91.7% [76.4%-99.3%], respectively; ptrend = 0.002). Fifty percent (50%) inhibition remained after 89.1 (38.0-129.7), 104.2 (17.6-190.8), and 112.4 (19.7-205.0) minutes. Injection site reactions or bruising were observed in 1 (4%) and 11 (41%) patients, respectively. Mild access-site haematomas occurred in 6 (22%), and severe access-site haematomas occurred in 2 patients (7%). No thrombocytopaenia was observed within 72 hours post dose. Conclusions: In patients with STEMI, a single subcutaneous dose of RUC-4 at 0.075, 0.090, and 0.110 mg/kg showed dose-response high-grade inhibition of platelet function within 15 minutes.
Brandt JN, Kim Y
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Targeting Polo-like kinase in space and time during C. elegans meiosis

CELL CYCLE 2021 AUG 18; 20(16):1519-1526
A central player in meiotic chromosome dynamics is the conserved Polo-like kinase (PLK) family. PLKs are dynamically localized to distinct structures during meiotic prophase and phosphorylate a diverse group of substrates to control homolog pairing, synapsis, and meiotic recombination. In a recent study, we uncovered the mechanisms that control the targeting of a meiosis-specific PLK-2 in C. elegans. In early meiotic prophase, PLK-2 localizes to special chromosome regions known as pairing centers and drives homolog pairing and synapsis. PLK-2 then relocates to the synaptonemal complex (SC) after crossover designation and mediates chromosome remodeling required for homolog separation. What controls this intricate targeting of PLK-2 in space and time? We discuss recent findings and remaining questions for the future.
Gleicher N, Patrizio P, Brivanlou A
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Preimplantation Genetic Testing for Aneuploidy - a Castle Built on Sand

TRENDS IN MOLECULAR MEDICINE 2021 AUG; 27(8):731-742
Preimplantation genetic testing for aneuploidy (PGT-A) has become a routine add-on for in vitro fertilization (IVF) to determine whether human embryos are to be clinically utilized or disposed of. Studies claiming IVF outcome improvements following PGT-A, however, used highly selected patient populations or inappropriate statistical methodologies. PGT-A was never clinically validated in its ability to define a human embryo as chromosomal normal, mosaic, or aneuploid, nor certified by a regulatory body, or an authoritative professional organization. Because of a high false-positive rate, PGT-A, actually reduces live IVF birth chances for many patients. Furthermore, in recent studies the PGT-A hypothesis was demonstrated to be mistaken for biological, mathematical and technical reasons. PGT-A, therefore, should clinically only be offered within experimental study frameworks.
Kaustio M, Nayebzadeh N, Hinttala R, Tapiainen T, Astrom P, Mamia K, Pernaa N, Lehtonen J, Glumoff V, Rahikkala E, Honkila M, Olsen P, Hassinen A, Polso M, Al Sukaiti N, Al Shekaili J, Al Kindi M, Al Hashmi N, Almusa H, Bulanova D, Haapaniemi E, Chen P, Suo-Palosaari M, Vieira P, Tuominen H, Kokkonen H, Al Macki N, Al Habsi H, Lopponen T, Rantala H, Pietiainen V, Zhang SY, Renko M, Hautala T, Al Farsi T, Uusimaa J, Saarela J
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Loss of DIAPH1 causes SCBMS, combined immunodeficiency, and mitochondrial dysfunction

JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY 2021 AUG; 148(2):599-611
Background: Homozygous loss of DIAPH1 results in seizures, cortical blindness, and microcephaly syndrome (SCBMS). We studied 5 Finnish and 2 Omani patients with loss of DIAPH1 presenting with SCBMS, mitochondrial dysfunction, and immunodeficiency. Objective: We sought to further characterize phenotypes and disease mechanisms associated with loss of DIAPH1. Methods: Exome sequencing, genotyping and haplotype analysis, B- and T-cell phenotyping, in vitro lymphocyte stimulation assays, analyses of mitochondrial function, immunofluorescence staining for cytoskeletal proteins and mitochondria, and CRISPR-Cas9 DIAPH1 knockout in heathy donor PBMCs were used. Results: Genetic analyses found all Finnish patients homozygous for a rare DIAPH1 splice-variant (NM_005219:c.68411G>A) enriched in the Finnish population, and Omani patients homozygous for a previously described pathogenic DIAPH1 frameshift-variant (NM_005219:c.2769delT;p.F923fs). In addition to microcephaly, epilepsy, and cortical blindness characteristic to SCBMS, the patients presented with infection susceptibility due to defective lymphocyte maturation and 3 patients developed B-cell lymphoma. Patients' immunophenotype was characterized by poor lymphocyte activation and proliferation, defective B-cell maturation, and lack of naive T cells. CRISPR-Cas9 knockout of DIAPH1 in PBMCs from healthy donors replicated the T-cell activation defect. Patient-derived peripheral blood T cells exhibited impaired adhesion and inefficient microtubule-organizing center repositioning to the immunologic synapse. The clinical symptoms and laboratory tests also suggested mitochondrial dysfunction. Experiments with immortalized, patient-derived fibroblasts indicated that DIAPH1 affects the amount of complex IV of the mitochondrial respiratory chain. Conclusions: Our data demonstrate that individuals with SCBMS can have combined immune deficiency and implicate defective cytoskeletal organization and mitochondrial dysfunction in SCBMS pathogenesis.
La Rocca G, King B, Shui B, Li XY, Zhang MS, Akat KM, Ogrodowski P, Mastroleo C, Chen K, Cavalieri V, Ma YL, Anelli V, Betel D, Vidigal J, Tuschl T, Meister G, Thompson CB, Lindsten T, Haigis K, Ventura A
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Inducible and reversible inhibition of miRNA-mediated gene repression in vivo

ELIFE 2021 AUG 31; 10(?):? Article e70948
Although virtually all gene networks are predicted to be controlled by miRNAs, the contribution of this important layer of gene regulation to tissue homeostasis in adult animals remains unclear. Gain and loss-of-function experiments have provided key insights into the specific function of individual miRNAs, but effective genetic tools to study the functional consequences of global inhibition of miRNA activity in vivo are lacking. Here we report the generation and characterization of a genetically engineered mouse strain in which miRNA-mediated gene repression can be reversibly inhibited without affecting miRNA biogenesis or abundance. We demonstrate the usefulness of this strategy by investigating the consequences of acute inhibition of miRNA function in adult animals. We find that different tissues and organs respond differently to global loss of miRNA function. While miRNA-mediated gene repression is essential for the homeostasis of the heart and the skeletal muscle, it is largely dispensable in the majority of other organs. Even in tissues where it is not required for homeostasis, such as the intestine and hematopoietic system, miRNA activity can become essential during regeneration following acute injury. These data support a model where many metazoan tissues primarily rely on miRNA function to respond to potentially pathogenic events.