Multicellular organisms require controlled intercellular communication for their survival. Strains of the filamentous cyanobacterium Nostoc regulate cell-cell communication between sister cells via a conformational change in septal junctions. These multi-protein cell junctions consist of a septum spanning tube with a membrane-embedded plug at both ends, and a cap covering the plug on the cytoplasmic side. The identities of septal junction components are unknown, with exception of the protein FraD. Here, we identify and characterize a FraD-interacting protein, SepN, as the second component of septal junctions in Nostoc. We use cryo-electron tomography of cryo-focused ion beam-thinned cyanobacterial filaments to show that septal junctions in a sepN mutant lack a plug module and display an aberrant cap. The sepN mutant exhibits highly reduced cell-cell communication rates, as shown by fluorescence recovery after photobleaching experiments. Furthermore, the mutant is unable to gate molecule exchange through septal junctions and displays reduced filament survival after stress. Our data demonstrate the importance of controlling molecular diffusion between cells to ensure the survival of a multicellular organism.
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http://dx.doi.org/10.1038/s41467-022-34946-7 | DOI Listing |
Clin Pract Cases Emerg Med
November 2024
Sher-i-Kashmir Institute of Medical Sciences Soura, Department of Anesthesia, Srinagar, Jammu and Kashmir, India.
Introduction: Although myocardial injury is common after blunt chest trauma, tricuspid valve injury associated with traumatic atrial septal defect resulting in acute hypoxia is an infrequent event. We report an unusual case of blunt chest trauma referred to us for unexplained hypoxemia, emphasizing the unusual nature of injury and the importance of comprehensive cardiac evaluation in such cases.
Case Report: A 35-year-old male presented to the emergency department after falling from a tree from an approximate height of 15 feet.
Ann Pediatr Cardiol
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Department of Cardiothoracic and Vascular Surgery, The Madras Medical Mission Hospital, Chennai, Tamil Nadu, India.
Objective: Skull base defects can be challenging to reconstruct. The nasoseptal flap (NSF) remains the first-line option for reconstruction. However, it can be inadequate to cover wide defects or compromised by tumor invasion or prior surgery requiring additional reconstructive options.
View Article and Find Full Text PDFCardiol Young
October 2024
Pediatric Cardiac Surgery, Saitama Medical University International Medical Center, Hidaka, Saitama, Japan.
A six-month-old boy with Down syndrome, complete atrioventricular septal defect with intact atrial septum, and moderate left-sided atrioventricular valve regurgitation underwent surgery. The presence of a common atrioventricular junction could not be diagnosed preoperatively. Postoperative left-sided atrioventricular valve regurgitation remained mild by complete cleft closure, direct closure of incised atrial septum, and patch augmentation of the underside of septum primum.
View Article and Find Full Text PDFCardiol Young
October 2024
Department of Thoracic and Cardiovascular Surgery, Hirosaki University School of Medicine, Hirosaki, Aomori, Japan.
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