SARS-CoV-2 is a positive sense RNA coronavirus that constitutes a new threat for the global community and economy. While vaccines against SARS-CoV-2 are being developed, the mechanisms through which this virus takes control of an infected cell to replicate remains poorly understood. Upon infection, viruses completely rely on host cell molecular machinery to survive and replicate. To escape from the immune response and proliferate, viruses strategically modulate cellular metabolism and alter subcellular organelle architecture and functions. One way they do this is by modulating the structure and function of mitochondria, a critical cellular metabolic hub but also a key platform for the regulation of cellular immunity. This versatile nature of mitochondria defends host cells from viruses through several mechanisms including cellular apoptosis, ROS signaling, MAVS activation and mitochondrial DNA-dependent immune activation. These events are regulated by mitochondrial dynamics, a process by which mitochondria alter their structure (including their length and connectivity) in response to stress or other cues. It is therefore not surprising that viruses, including coronaviruses hijack these processes for their survival. In this review, we highlight how positive sense RNA viruses modulate mitochondrial dynamics and metabolism to evade mitochondrial mediated immune response in order to proliferate.

Organelles cooperate with each other to regulate vital cellular homoeostatic functions. This occurs through the formation of close connections through membrane contact sites. Mitochondria-Endoplasmic-Reticulum (ER) contact sites (MERCS) are one of such contact sites that regulate numerous biological processes by controlling calcium and metabolic homeostasis. However, the extent to which contact sites shape cellular biology and the underlying mechanisms remain to be fully elucidated. A number of biochemical and imaging approaches have been established to address these questions, resulting in the identification of a number of molecular tethers between mitochondria and the ER. Among these techniques, fluorescence-based imaging is widely used, including analysing signal overlap between two organelles and more selective techniques such as in-situ proximity ligation assay (PLA). While these two techniques allow the detection of endogenous proteins, preventing some problems associated with techniques relying on overexpression (FRET, split fluorescence probes), they come with their own issues. In addition, proper image analysis is required to minimise potential artefacts associated with these methods. In this review, we discuss the protocols and outline the limitations of fluorescence-based approaches used to assess MERCs using endogenous proteins.

Commonly used local anaesthetic (LA) solutions in the field of dentistry are acidic, and have been known to cause pain and a burning sensation. The present study aimed to determine the pH levels of commercially available LA solutions with and without adrenaline and 8.4% sodium bicarbonate-buffered LA solution, and to evaluate the pain during the administration of buffered and non-buffered LA solutions. For this purpose, 20 patients with deep dentinal carious lesions with pulpal involvement affecting the bilateral posterior teeth and requiring the administration of a local nerve block were randomly selected to receive buffered and non-buffered LA agents on either side, respectively. The patients were instructed to score the pain perceived during LA administration with the aid of a visual analogue scale (VAS) score of 1-10. All the data obtained were subjected to statistical analysis. The results revealed that the LA solution of 2% lignocaine with 1:80,000 adrenaline buffered with sodium bicarbonate had a mean (± SD) pH level of 6.92±0.34 and non-buffered LA solution had a mean pH level of 3.49±0.26. As per the VAS, a greater level of pain was reported during the non-buffered LA administration (3.15±1.27) compared to the buffered LA administration (1.40±0.68). Buffered local anaesthetics were more likely than non-buffered solutions to achieve successful anaesthesia [95% confidence interval (CI), 1.09-2.41; P<0.001]. On the whole, the present study demonstrates that a significant reduction in the pain perceived in patients during the administration of LA agents buffered with sodium bicarbonate when used during pulpal involvement.