4-(4-Meth­oxy­phen­yl)naphtho­[2,3-b]thio­phene

In the title compound, C19H14OS, the naphtho­thio­phene moiety is almost planar except for the S atom of the five-membered ring, which is situated 0.047 (6) Å out of the C4 plane (with an r.m.s. deviation of fitted atoms = 0.0009 Å). The dihedral angle between the naphtho­thio­phene plane and the attached meth­oxy­phenyl ring is 67.6 (2)°. In the crystal, a C—H⋯π inter­action is observed between a meth­oxy­phenyl C—H group and the outer benzene ring of the naphtho­thio­phene moiety. The five-membered ring of the naphtho­thio­phene moiety is disordered, with the S and opposite non-fused C atom approximately exchanging positions, with a site-occupancy factors of 0.808 (3) and 0.187 (3)

5-Methyl-12-phenyl­sulfonyl-12H-naphtho­[1,2-b]carbazole

In the title compound, C27H19NO2S, the naphtho­carbazole unit is approximately planar (r.m.s. deviation = 0.002 Å) except for the N atom, which is displaced by 0.122 (1) Å out of the mean plane. The dihedral angle between the naphtho­carbazole mean plane and the phenyl ring of the phenyl­sulfonyl substituent is 83.16 (3)°. An inter­molecular C—H⋯π inter­action involving the phenyl group and the pyrrole ring is observed in the crystal structure

Catalase and ascorbate peroxidase—representative H2O2-detoxifying heme enzymes in plants

Plants have to counteract unavoidable stress-caused anomalies such as oxidative stress to sustain their lives and serve heterotrophic organisms including humans. Among major enzymatic antioxidants, catalase (CAT; EC 1.11.1.6) and ascorbate peroxidase (APX; EC 1.11.1.11) are representative heme enzymes meant for metabolizing stress-provoked reactive oxygen species (ROS; such as H2O2) and controlling their potential impacts on cellular metabolism and functions. CAT mainly occurs in peroxisomes and catalyzes the dismutation reaction without requiring any reductant; whereas, APX has a higher affinity for H2O2 and utilizes ascorbate (AsA) as specific electron donor for the reduction of H2O2 into H2O in organelles including chloroplasts, cytosol, mitochondria, and peroxisomes. Literature is extensive on the glutathione-associated H2O2-metabolizing systems in plants. However, discussion is meager or scattered in the literature available on the biochemical and genomic characterization as well as techniques for the assays of CAT and APX and their modulation in plants under abiotic stresses. This paper aims (a) to introduce oxidative stress-causative factors and highlights their relationship with abiotic stresses in plants; (b) to overview structure, occurrence, and significance of CAT and APX in plants; (c) to summarize the principles of current technologies used to assay CAT and APX in plants; (d) to appraise available literature on the modulation of CAT and APX in plants under major abiotic stresses; and finally, (e) to consider a brief cross-talk on the CAT and APX, and this also highlights the aspects unexplored so far

Characteristics of Anti-SARS-CoV-2 Antibodies in Recovered COVID-19 Subjects

Coronavirus Disease 2019 (COVID-19) is a global pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While detection of SARS-CoV-2 by polymerase chain reaction with reverse transcription (RT-PCR) is currently used to diagnose acute COVID-19 infection, serological assays are needed to study the humoral immune response to SARS-CoV-2. Anti-SARS-CoV-2 immunoglobulin (Ig)G/A/M antibodies against spike (S) protein and its receptor-binding domain (RBD) were characterized in recovered subjects who were RT-PCR-positive (n = 153) and RT-PCR-negative (n = 55) using an enzyme-linked immunosorbent assay (ELISA). These antibodies were also further assessed for their ability to neutralize live SARS-CoV-2 virus. Anti-SARS-CoV-2 antibodies were detected in 90.9% of resolved subjects up to 180 days post-symptom onset. Anti-S protein and anti-RBD IgG titers correlated (r = 0.5157 and r = 0.6010, respectively) with viral neutralization. Of the RT-PCR-positive subjects, 22 (14.3%) did not have anti-SARS-CoV-2 antibodies; and of those, 17 had RT-PCR cycle threshold (Ct) values > 27. These high Ct values raise the possibility that these indeterminate results are from individuals who were not infected or had mild infection that failed to elicit an antibody response. This study highlights the importance of serological surveys to determine population-level immunity based on infection numbers as determined by RT-PCR