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About 106,488 results

A Flexible Chamber for Time-Lapse Live-Cell Imaging with Stimulated Raman Scattering Mi...
https://doi.org/10.3791/64449
Journal of Visualized Experiments : JoVE; Yuan Y, Lu F

Sep 20th, 2022 - Stimulated Raman scattering (SRS) microscopy is a label-free chemical imaging technology. Live-cell imaging with SRS has been demonstrated for many biological and biomedical applications. However, long-term time-lapse SRS imaging of live cells has not been widely adopted. SRS microscopy often uses a high numerical aperture (NA) water-immersion objective and a high NA oil-immersion condenser to ...

Mitochondria to Bitter Melon: Understanding the 3D Ultrastructure of the Cell Via 2D Th...
https://doi.org/10.1007/978-3-031-10889-1_5
Advances in Experimental Medicine and Biology; Mazierski DM

Sep 15th, 2022 - The origin of histology-the study of microscopic anatomy-is intimately connected with the development of the light microscope and improvements in lens design and manufacture.However, knowledge of the ultrastructure of the cell was hampered by the very nature of light microscopy, which, due to the physical properties of the visible electromagnetic spectrum, could never provide the magnification ...

Layer 5 of cortex innervates the thalamic reticular nucleus in mice.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9499584
Proceedings of the National Academy of Sciences of the Un... Carroll BJ, Sampathkumar V et. al.

Sep 13th, 2022 - Neurons in the thalamic reticular nucleus (TRN) are a primary source of inhibition to the dorsal thalamus and, as they are innervated in part by the cortex, are a means of corticothalamic regulation. Previously, cortical inputs to the TRN were thought to originate solely from layer 6 (L6), but we recently reported the presence of putative synaptic terminals from layer 5 (L5) neurons in multiple...

Disruption of mitochondria-sarcoplasmic reticulum microdomain connectomics contributes ...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9456763
Proceedings of the National Academy of Sciences of the Un... Ren L, Gopireddy RR et. al.

Sep 1st, 2022 - The sinoatrial node (SAN), the leading pacemaker region, generates electrical impulses that propagate throughout the heart. SAN dysfunction with bradyarrhythmia is well documented in heart failure (HF). However, the underlying mechanisms are not completely understood. Mitochondria are critical to cellular processes that determine the life or death of the cell. The release of Ca2+ from the ryano...

Cryo-EM Structure and Functional Studies of EBNA1 Binding to the Family of Repeats and ...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9472633
Journal of Virology; Mei Y, Messick TE et. al.

Aug 30th, 2022 - Epstein-Barr nuclear antigen 1 (EBNA1) is a multifunctional viral-encoded DNA-binding protein essential for Epstein-Barr virus (EBV) DNA replication and episome maintenance. EBNA1 binds to two functionally distinct elements at the viral origin of plasmid replication (oriP), termed the dyad symmetry (DS) element, required for replication initiation and the family of repeats (FR) required for epi...

R-loop formation and conformational activation mechanisms of Cas9.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9433323
Nature Pacesa M, Loeff L et. al.

Aug 25th, 2022 - Cas9 is a CRISPR-associated endonuclease capable of RNA-guided, site-specific DNA cleavage1-3. The programmable activity of Cas9 has been widely utilized for genome editing applications4-6, yet its precise mechanisms of target DNA binding and off-target discrimination remain incompletely understood. Here we report a series of cryo-electron microscopy structures of Streptococcus pyogenes Cas9 ca...

Mechanism of AAA+ ATPase-mediated RuvAB-Holliday junction branch migration.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9477746
Nature Wald J, Fahrenkamp D et. al.

Aug 25th, 2022 - The Holliday junction is a key intermediate formed during DNA recombination across all kingdoms of life1. In bacteria, the Holliday junction is processed by two homo-hexameric AAA+ ATPase RuvB motors, which assemble together with the RuvA-Holliday junction complex to energize the strand-exchange reaction2. Despite its importance for chromosome maintenance, the structure and mechanism by which t...

Structure of a cholinergic cell membrane.
https://doi.org/10.1073/pnas.2207641119
Proceedings of the National Academy of Sciences of the Un... Unwin N

Aug 16th, 2022 - Cell membranes are complex assemblies of proteins and lipids making transient or long-term associations that have yet to be characterized at a molecular level. Here, cryo-electron microscopy is applied to determine how phospholipids and cholesterol arrange between neighboring proteins (nicotinic acetylcholine receptors) of Torpedo cholinergic membrane. The lipids exhibit distinct properties in ...

Distinct neural networks derived from galanin-containing nociceptors and neurotensin-ex...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9388111
Proceedings of the National Academy of Sciences of the Un... Chen Y, Song Y et. al.

Aug 10th, 2022 - Pain and itch are distinct sensations arousing evasion and compulsive desire for scratching, respectively. It's unclear whether they could invoke different neural networks in the brain. Here, we use the type 1 herpes simplex virus H129 strain to trace the neural networks derived from two types of dorsal root ganglia (DRG) neurons: one kind of polymodal nociceptors containing galanin (Gal) and o...

Structure of Human Enterovirus 70 and Its Inhibition by Capsid-Binding Compounds.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9472761
Journal of Virology; Füzik T, Moravcová J et. al.

Aug 9th, 2022 - Enterovirus 70 (EV70) is a human pathogen belonging to the family Picornaviridae. EV70 is transmitted by eye secretions and causes acute hemorrhagic conjunctivitis, a serious eye disease. Despite the severity of the disease caused by EV70, its structure is unknown. Here, we present the structures of the EV70 virion, altered particle, and empty capsid determined by cryo-electron microscopy. The ...

Whole-brain neuronal MCT2 lactate transporter expression links metabolism to human brai...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9388117
Proceedings of the National Academy of Sciences of the Un... Medel V, Crossley N et. al.

Aug 9th, 2022 - Brain activity is constrained by local availability of chemical energy, which is generated through compartmentalized metabolic processes. By analyzing data of whole human brain gene expression, we characterize the spatial distribution of seven glucose and monocarboxylate membrane transporters that mediate astrocyte-neuron lactate shuttle transfer of energy. We found that the gene coding for neu...

Rotavirus VP4 Epitope of a Broadly Neutralizing Human Antibody Defined by Its Structure...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9400500
Journal of Virology; Jenni S, Li Z et. al.

Aug 5th, 2022 - Rotavirus live-attenuated vaccines, both mono- and pentavalent, generate broadly heterotypic protection. B-cells isolated from adults encode neutralizing antibodies, some with affinity for VP5*, that afford broad protection in mice. We have mapped the epitope of one such antibody by determining the high-resolution cryo-EM structure of its antigen-binding fragment (Fab) bound to the virion of a ...

Architecture and self-assembly of the jumbo bacteriophage nuclear shell.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9365700
Nature Laughlin TG, Deep A et. al.

Aug 4th, 2022 - Bacteria encode myriad defences that target the genomes of infecting bacteriophage, including restriction-modification and CRISPR-Cas systems1. In response, one family of large bacteriophages uses a nucleus-like compartment to protect its replicating genomes by excluding host defence factors2-4. However, the principal composition and structure of this compartment remain unknown. Here we find th...

Quantitative, in situ visualization of intracellular insulin vesicles in pancreatic bet...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9371705
Proceedings of the National Academy of Sciences of the Un... Guo A, Zhang J et. al.

Aug 4th, 2022 - Characterizing relationships between Zn2+, insulin, and insulin vesicles is of vital importance to the study of pancreatic beta cells. However, the precise content of Zn2+ and the specific location of insulin inside insulin vesicles are not clear, which hinders a thorough understanding of the insulin secretion process and diseases caused by blood sugar dysregulation. Here, we demonstrated the c...

Structures and mechanisms of the Arabidopsis auxin transporter PIN3.
https://doi.org/10.1038/s41586-022-05142-w
Nature Su N, Zhu A et. al.

Aug 3rd, 2022 - The PIN-FORMED (PIN) protein family of auxin transporters mediates polar auxin transport and has crucial roles in plant growth and development1,2. Here we present cryo-electron microscopy structures of PIN3 from Arabidopsis thaliana in the apo state and in complex with its substrate indole-3-acetic acid and the inhibitor N-1-naphthylphthalamic acid (NPA). A. thaliana PIN3 exists as a homodimer,...

Structural insight and characterization of human Twinkle helicase in mitochondrial dise...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9371709
Proceedings of the National Academy of Sciences of the Un... Riccio AA, Bouvette J et. al.

Aug 2nd, 2022 - Twinkle is the mammalian helicase vital for replication and integrity of mitochondrial DNA. Over 90 Twinkle helicase disease variants have been linked to progressive external ophthalmoplegia and ataxia neuropathies among other mitochondrial diseases. Despite the biological and clinical importance, Twinkle represents the only remaining component of the human minimal mitochondrial replisome that ...

In vitro investigation of protein assembly by combined microscopy and infrared spectros...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9371722
Proceedings of the National Academy of Sciences of the Un... Zhao X, Li D et. al.

Aug 2nd, 2022 - The nanoscale structure and dynamics of proteins on surfaces has been extensively studied using various imaging techniques, such as transmission electron microscopy and atomic force microscopy (AFM) in liquid environments. These powerful imaging techniques, however, can potentially damage or perturb delicate biological material and do not provide chemical information, which prevents a fundament...

Molecular interplay of an assembly machinery for nitrous oxide reductase.
https://doi.org/10.1038/s41586-022-05015-2
Nature Müller C, Zhang L et. al.

Jul 28th, 2022 - Emissions of the critical ozone-depleting and greenhouse gas nitrous oxide (N2O) from soils and industrial processes have increased considerably over the last decades1-3. As the final step of bacterial denitrification, N2O is reduced to chemically inert N2 (refs. 1,4) in a reaction that is catalysed by the copper-dependent nitrous oxide reductase (N2OR) (ref. 5). The assembly of its unique [4Cu...

Functionalized Mesoporous Silica Nanoparticles for Drug-Delivery to Multidrug-Resistant...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9293248
International Journal of Nanomedicine; Igaz N, Bélteky P et. al.

Jul 22nd, 2022 - Multidrug resistance is a common reason behind the failure of chemotherapy. Even if the therapy is effective, serious adverse effects might develop due to the low specificity and selectivity of antineoplastic agents. Mesoporous silica nanoparticles (MSNs) are promising materials for tumor-targeting and drug-delivery due to their small size, relatively inert nature, and extremely large specific ...

Membrane-anchored HDCR nanowires drive hydrogen-powered CO2 fixation.
https://doi.org/10.1038/s41586-022-04971-z
Nature Dietrich HM, Righetto RD et. al.

Jul 22nd, 2022 - Filamentous enzymes have been found in all domains of life, but the advantage of filamentation is often elusive1. Some anaerobic, autotrophic bacteria have an unusual filamentous enzyme for CO2 fixation-hydrogen-dependent CO2 reductase (HDCR)2,3-which directly converts H2 and CO2 into formic acid. HDCR reduces CO2 with a higher activity than any other known biological or chemical catalyst4,5, a...