SARS-CoV-2 Nucleocapsid Protein Has DNA-Melting and Strand-Annealing Activities With Different Properties From SARS-CoV-2 Nsp13.

Since December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread throughout the world and has had a devastating impact on health and economy. The biochemical characterization of SARS-CoV-2 proteins is important for drug design and development. In this study, we discovered that the SARS-CoV-2 nucleocapsid protein can melt double-stranded DNA (dsDNA) in the 5'-3' direction, similar to SARS-CoV-2 nonstructural protein 13. However, the unwinding activity of SARS-CoV-2 nucleocapsid protein was found to be more than 22 times weaker than that of SARS-CoV-2 nonstructural protein 13, and the melting process was independent of nucleoside triphosphates and Mg2+. Interestingly, at low concentrations, the SARS-CoV-2 nucleocapsid protein exhibited a stronger annealing activity than SARS-CoV-2 nonstructural protein 13; however, at high concentrations, it promoted the melting of dsDNA. These findings have deepened our understanding of the SARS-CoV-2 nucleocapsid protein and will help provide novel insights into antiviral drug development.

Correlation between white matter damage and gray matter lesions in multiple sclerosis patients.

We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. We analyzed the correlation between fractional anisotropy values and changes in whole-brain gray matter volume. The participants included 20 patients with relapsing-remitting multiple sclerosis and 20 healthy volunteers as controls. All subjects underwent head magnetic resonance imaging and diffusion tensor imaging. Our results revealed that fractional anisotropy values decreased and gray matter volumes were reduced in the genu and splenium of corpus callosum, left anterior thalamic radiation, hippocampus, uncinate fasciculus, right corticospinal tract, bilateral cingulate gyri, and inferior longitudinal fasciculus in multiple sclerosis patients. Gray matter volumes were significantly different between the two groups in the right frontal lobe (superior frontal, middle frontal, precentral, and orbital gyri), right parietal lobe (postcentral and inferior parietal gyri), right temporal lobe (caudate nucleus), right occipital lobe (middle occipital gyrus), right insula, right parahippocampal gyrus, and left cingulate gyrus. The voxel sizes of atrophic gray matter positively correlated with fractional anisotropy values in white matter association fibers in the patient group. These findings suggest that white matter fiber bundles are extensively injured in multiple sclerosis patients. The main areas of gray matter atrophy in multiple sclerosis are the frontal lobe, parietal lobe, caudate nucleus, parahippocampal gyrus, and cingulate gyrus. Gray matter atrophy is strongly associated with white matter injury in multiple sclerosis patients, particularly with injury to association fibers.

Primary diffuse large B-cell lymphoma of the dura with skull and scalp involvement: A case report and brief review of the literature.

Primary dural lymphoma (PDL) refers to a lymphoma with epidural or subdural involvement and is a rare subtype of primary central nervous system lymphoma. Diffuse large B-cell lymphoma (DLBCL) presenting as PDL is extremely rare. The present study reports a case of PDL with skull and scalp involvement in a 56-year-old man. Magnetic resonance imaging (MRI) revealed that the tumor was located under the right parietal inner plate and was attached to the dura mater. Following contrast-enhanced MRI, markedly enhanced tumor signals were observed, and mild homogeneous enhancement was observed in the diploë and soft tissues under the scalp, near the parietal bone. Under general anesthesia, the patient underwent craniotomy and tumor resection. The postoperative pathological diagnosis was DLBCL. Tumors were additionally identified inside the skull and subcutaneous tissues. The patient was administered chemotherapy postoperatively, and the prognosis subsequent to the 4-year follow-up was favorable. Primary malignant lymphoma should be considered in the differential diagnosis of scalp masses and meningeal lesions. Early diagnosis and individualized treatment is closely associated with a favorable outcome.