Engineering RNA polymerase to construct biotechnological host strains of cyanobacteria.

Application of cyanobacteria for bioproduction, bioremediation and biotransformation is being increasingly explored. Photoautotrophs are carbon-negative by default, offering a direct pathway to reducing emissions in production systems. More robust and versatile host strains are needed for constructing production strains that would function as efficient and carbon-neutral cyanofactories. We have tested if the engineering of sigma factors, regulatory units of the bacterial RNA polymerase, could be used to generate better host strains of the model cyanobacterium Synechocystis sp. PCC 6803. Overexpressing the stress-responsive sigB gene under the strong psbA2 promoter (SigB-oe) led to improved tolerance against heat, oxidative stress and toxic end-products. By targeting transcription initiation in the SigB-oe strain, we could simultaneously activate a wide spectrum of cellular protective mechanisms, including carotenoids, the HspA heat shock protein, and highly activated non-photochemical quenching. Yellow fluorescent protein was used to test the capacity of the SigB-oe strain to produce heterologous proteins. In standard conditions, the SigB-oe strain reached a similar production as the control strain, but when cultures were challenged with oxidative stress, the production capacity of SigB-oe surpassed the control strain. We also tested the production of growth-rate-controlled host strains via manipulation of RNA polymerase, but post-transcriptional regulation prevented excessive overexpression of the primary sigma factor SigA, and overproduction of the growth-restricting SigC factor was lethal. Thus, more research is needed before cyanobacteria growth can be manipulated by engineering RNA polymerase.

In-silico drug design for the novel Karachi-NF001 strain of brain-eating amoeba: Naegleria fowleri.

Naegleria fowleri (N. fowleri) is a free-living thermophilic amoeba of fresh water and soil. The amoeba primarily feeds on bacteria but can be transmitted to humans upon contact with freshwater sources. Furthermore, this brain-eating amoeba enters the human body through the nose and travels to the brain to cause primary amebic meningoencephalitis (PAM). N. fowleri has been reported globally since its discovery in 1961. Recently a new strain of N. fowleri named Karachi-NF001 was found in a patient who had traveled from Riyadh, Saudi Arabia to Karachi in 2019. There were 15 unique genes identified in the genome of the Karachi-NF001 strain compared to all the previously reported strains of N. fowleri worldwide. Six of these genes encode well-known proteins. In this study, we performed in-silico analysis on 5 of these 6 proteins, namely, Rab family small GTPase, NADH dehydrogenase subunit 11, two Glutamine-rich protein 2 proteins (locus tags: 12086 and 12110), and Tigger transposable element-derived protein 1. We conducted homology modeling of these 5 proteins followed by their active site identification. These proteins were subjected to molecular docking against 105 anti-bacterial ligand compounds as potential drugs. Subsequently, the 10 best-docked compounds were determined for each protein and ranked according to the number of interactions and their binding energies. The highest binding energy was recorded for the two Glutamine-rich protein 2 proteins with different locus tags, and results have shown that the protein-inhibitor complex was stable throughout the simulation run. Moreover, future in-vitro studies could validate the findings of our in-silico analysis and identify potential therapeutic drugs against N. fowleri infections.

Zika Virus from the Perspective of Observational Studies: a Review.

Background: Since 1952 when Zika Virus (ZIKV): a Flavivirus, was first discovered in humans, it has not received enough scientific research compared to some of the other members of the family Flaviviridae; like Dengue Virus (DENV). However, this has not stopped the virus from infecting the human population globally. In particular, the global spread of ZIKV has led to a surge in observational studies. Methods: Regarding recently published ZIKV-related literature, we are not aware of any reviews strictly focusing on ZIKV from the perspective of observational studies. Therefore, we reviewed recently published observational studies exploring the global spread of ZIKV and its association with Congenital ZIKV Infection (CZI) and clinical manifestations in adults. Online databases including google scholar, PubMed and Elsevier were used for retrieving relevant studies. Results: ZIKV cases have been reported in different parts of the world, with certain regions reporting more cases than the rest, like Brazil. ZIKV causes a wide spectrum of diseases and disorders including microcephaly, developmental disorders, and Guillain-Barre syndrome to name a few. Furthermore, CZI in neonates mainly manifests into neurological disorders and diseases, whereas ZIKV in adults' targets various organs. Conclusion: ZIKV poses a serious threat to human population and observational studies provide a different perspective on the damaging capabilities of ZIKV in real-life settings. Moreover, there are gaps in the literature regarding ZIKV-related-complications that future experimental studies need to address. These complications include in-utero transmission, Guillain-Barre syndrome, cross-reactivity, sexual transmission, along with its persistence in the male reproductive tract.