Antimitotic action of cornin as a biologically active polypeptide. I. Biochemical properties of cornin

We succeeded in the extraction of a substance from beef cornea and rabbit muscle, that markedly inhibits mitosis of sea urchin eggs. The substance extracted from beef cornea is non-dialysable and it can be separated into three fractions by DEAE-cellulose column. Although everyone of these fractions has an antimitotic action, that of fractions II and III is especially marked. These fractions are one of nucleoproteins that have adenine as base. The substance extracted from rabbit muscle is dialysable, and when it is fractionated through DEAE-cellulose column into three fractions, fraction I has no antimitotic effect but fractions II and III have it. Fraction II is one of nucleoproteins that have hypoxanthine as base. Carnin obtained from beef cornea or from rabbit muscle shows a typical protein wave, but after being treated with gas by passing oxygen through cornin solution the wave height is lowered. Carnin, however, is a very stable substance when kept dry in a desiccator.</p

Crystal structure of Schmallenberg orthobunyavirus nucleoprotein-RNA complex reveals a novel RNA sequestration mechanism

Schmallenberg virus (SBV) is a newly emerged orthobunyavirus (family Bunyaviridae) that has caused severe disease in the offspring of farm animals across Europe. Like all orthobunyaviruses, SBV contains a tripartite negative-sense RNA genome that is encapsidated by the viral nucleocapsid (N) protein in the form of a ribonucleoprotein complex (RNP). We recently reported the three-dimensional structure of SBV N that revealed a novel fold. Here we report the crystal structure of the SBV N protein in complex with a 42-nt-long RNA to 2.16 Å resolution. The complex comprises a tetramer of N that encapsidates the RNA as a cross-shape inside the protein ring structure, with each protomer bound to 11 ribonucleotides. Eight bases are bound in the positively charged cleft between the N- and C-terminal domains of N, and three bases are shielded by the extended N-terminal arm. SBV N appears to sequester RNA using a different mechanism compared with the nucleoproteins of other negative-sense RNA viruses. Furthermore, the structure suggests that RNA binding results in conformational changes of some residues in the RNA-binding cleft and the N- and C-terminal arms. Our results provide new insights into the novel mechanism of RNA encapsidation by orthobunyaviruses

On ultraviolet light and the origin of ribosomes

Function of UV light in evolution of contemporary ribosome

Nipah shell disorder, modes of infection, and virulence

The Nipah Virus (NiV) was first isolated during a 1998–9 outbreak in Malaysia. The outbreak initially infected farm pigs and then moved to humans from pigs with a case-fatality rate (CFR) of about 40%. After 2001, regular outbreaks occurred with higher CFRs (~71%, 2001–5, ~93%, 2008–12). The spread arose from drinking virus-laden palm date sap and human-to-human transmission. Intrinsic disorder analysis revealed strong correlation between the percentage of disorder in the N protein and CFR (Regression: r2 = 0.93, p < 0.01, ANOVA: p < 0.01). Distinct disorder and, therefore, genetic differences can be found in all three group of strains. The fact that the transmission modes of the Malaysia strain are different from those of the Bangladesh strains suggests that the correlations may also be linked to the modes of viral transmission. Analysis of the NiV and related viruses suggests links between modes of transmission and disorder of not just the N protein but, also, of M shell protein. The links among shell disorder, transmission modes, and virulence suggest mechanisms by which viruses are attenuated as they passed through different cell hosts from different animal species. These have implications for development of vaccines and epidemiological molecular analytical tools to contain outbreaks

Quantitative studies of nucleic acid in the cell by micro-spectrophotometry I. The critique and improvement of the microspectrophotometry

Some critical experiments have been carried out on the microspectrophotometry using the lymphocytes of a mouse, stained with Feulgen reaction, revealing that most reliable value can be attained by illuminating the material with a small spot-light and integrating the area surrounded by the extinction curve drawn by tracing along the diameter of the smeared and fixed cell.</p

Quantitative studies of nucleic acid in the cell by microspectrophotometry III. Nucleic acid contents in the cancer cells

1. The DNA contents in mature lymphocytes of the mouse, rat and man are kept almost constant. 2. The variety in the DNA contents in tumor cells is attributed to the rapid DNA synthesis taking place at the interphase, though the degenerating cells and the cells in abnormal mitosis can not be discarded as the source of the variety in DNA content. 3. The RNA content in AH-130 (ascites hepatoma) is less than that in normal liver cells.</p

Nucleoprotein content of "L" strain of Staphylococcus aureus

Thesis (M.A.)--Boston Universit

Prediction of Intrinsic Disorder in MERS-CoV/HCoV-EMC Supports a High Oral-Fecal Transmission

A novel coronavirus, MERS-CoV (NCoV, HCoV-EMC/2012), originating from the Middle-East, has been discovered. Incoming data reveal that the virus is highly virulent to humans. A model that categorizes coronaviuses according to the hardness of their shells was developed before the discovery of MERS-CoV. Using protein intrinsic disorder prediction, coronaviruses were categorized into three groups that can be linked to the levels of oral-fecal and respiratory transmission regardless of genetic proximity. Using this model, MERS-CoV is placed into disorder group C, which consists of coronaviruses that have relatively hard inner and outer shells. The members of this group are likely to persist in the environment for a longer period of time and possess the highest oral-fecal components but relatively low respiratory transmission components. Oral-urine and saliva transmission are also highly possible since both require harder protective shells. Results show that disorder prediction can be used as a tool that suggests clues to look for in further epidemiological investigations

Favourable antibody responses to human coronaviruses in children and adolescents with autoimmune rheumatic diseases

Background: Differences in humoral immunity to coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), between children and adults remain unexplained and the impact of underlying immune dysfunction or suppression unknown. Here, we sought to examine the antibody immune competence of children and adolescents with prevalent inflammatory rheumatic diseases, juvenile idiopathic arthritis (JIA), juvenile dermatomyositis (JDM) and juvenile systemic lupus erythematosus (JSLE), against the seasonal human coronavirus (HCoV)-OC43 that frequently infects this age group. // Methods: Sera were collected from JIA (n=118), JDM (n=49) and JSLE (n=30) patients, and from healthy control (n=54) children and adolescents, prior to the coronavirus disease-19 (COVID-19) pandemic. We employed sensitive flow cytometry-based assays to determine titres of antibodies that reacted with the spike and nucleoprotein of HCoV-OC43 and cross-reacted with the spike and nucleoprotein of SARS-CoV-2, and compared with respective titres in sera from patients with multisystem inflammatory syndrome in children and adolescents (MIS-C). // Findings: Despite immune dysfunction and immunosuppressive treatment, JIA, JDM and JSLE patients maintained comparable or stronger humoral responses than healthier peers, dominated by IgG antibodies to HCoV-OC43 spike, and harboured IgG antibodies that cross-reacted with SARS-CoV-2 spike. In contrast, responses to HCoV-OC43 and SARS-CoV-2 nucleoproteins exhibited delayed age-dependent class-switching and were not elevated in JIA, JDM and JSLE patients, arguing against increased exposure. // Conclusions: Consequently, autoimmune rheumatic diseases and their treatment were associated with a favourable ratio of spike to nucleoprotein antibodies