ABSTRACT
Background: Coronavirus 2019 infection (COVID 19) is an ongoing pandemic caused by pathogenic RNA viruses called severe acute respiratory syndrome coronavirus-2 (SARS-COV-2). It has affected people of all ages, with high morbidity and mortality among the elderly and immunocompromised population. Limited information is available on the effects of COVID-19 infection on pregnancy. Aim: To describe the histopathological changes in the placental tissue of SARS-CoV-2 infected term mothers with no comorbidities and to correlate with neonatal outcome. Materials and Methods: This observational study was conducted in the Department of Pathology, KMCH institute of health sciences and research, Coimbatore from May 1, 2020 to November 30, 2020 for 6 months. Placental tissues of all COVID-19-positive term mothers with no comorbidities were included in this study. Histopathological examination of placentae was carried out and clinical data of mothers and newborn babies were obtained from medical records. Results: Histopathological examination of 64 placental tissue of COVID-19 mothers showed predominantly the features of fetal vascular malperfusion like stem villi vasculature thrombus, villous congestion, and avascular villi. No significant correlation was obtained in comparison with parity and symptomatic status of the mothers. However, histopathological changes were more prominent among symptomatic patients. The newborn babies born to these mothers showed no adverse outcome. Conclusion: This study concluded that though COVID-19 infection in normal term pregnant women was associated with increased prevalence of features of fetal vascular malperfusion, there was no significant morbidity in the health status of both COVID-19 mothers and their neonates.
ABSTRACT
The Mcr systems (previously known as Rgl systems) of Escherichia coli recognize and cleave specific sequences carrying methylated or hydroxymethylated cytosines. We have cloned the mcrA gene and determined its nucleotide sequence. An 831 base pair sequence encodes the McrA protein. Analysis of the sequence data reveals that there arc additional ORFs internal to the above. A phage T7 expression system was used to determine the protein products encoded by the cloned mcrA gene. The results clearly show that a 31 kDa polypeptide is responsible for McrA activity. This is in agreement with the molecular weight deduced from sequence data. McrA protein was found to be localized in the outer membrane of Escherichia coli. To our knowledge this is the first restriction enzyme localized in the outer membrane of Escherichia coli.