Ecology and Function of the Transmissible Locus of Stress Tolerance in Escherichia coli and Plant-Associated Enterobacteriaceae

The transmissible locus of stress tolerance (tLST) is a genomic island comprising 10 core genes that occurs in diverse Enterobacteriaceae and confers resistance to heat and chlorine. Experimentation described in the manuscript describes the physiological function of the core genes by characterization of the resistance of 13 single-knockout (KO) mutants and by characterization of protein and membrane oxidation in these strains after chlorine challenge.

Oxidative Effects during Irreversible Electroporation of Melanoma Cells—In Vitro Study

Irreversible electroporation (IRE) is today used as an alternative to surgery for the excision of cancer lesions. This study aimed to investigate the oxidative and cytotoxic effects the cells undergo during irreversible electroporation using IRE protocols. To do so, we used IRE-inducing pulsed electric fields (PEFs) (eight pulses of 0.1 ms duration and 2–4 kV/cm intensity) and compared their effects to those of PEFs of intensities below the electroporation threshold (eight pulses, 0.1 ms, 0.2–0.4 kV/cm) and the PEFs involving elongated pulses (eight pulses, 10 ms, 0.2–0.4 kV/cm). Next, to follow the morphology of the melanoma cell membranes after treatment with the PEFs, we analyzed the permeability and integrity of their membranes and analyzed the radical oxygen species (ROS) bursts and the membrane lipids’ oxidation. Our data showed that IRE-induced high cytotoxic effect is associated both with irreversible cell membrane disruption and ROS-associated oxidation, which is occurrent also in the low electric field range. It was shown that the viability of melanoma cells characterized by similar ROS content and lipid membrane oxidation after PEF treatment depends on the integrity of the membrane system. Namely, when the effects of the PEF on the membrane are reversible, aside from the high level of ROS and membrane oxidation, the cell does not undergo cell death.

Acid Sphingomyelinase Deficiency Normalizes Neuronal Function in GCase Deficiency - Unexpected Biological Rescue Effect of Combined Genetic Risk Factors for Parkinson’s Disease

BackgroundThe additive mechanistic effect of genetic risk variants for Parkinson’s disease (PD) is a plausible but largely unproven hypothesis. We investigated the mechanistic interaction between the two lysosomal PD risk genes glucocerebrosidase 1 (GBA1) and sphingomyelinase 1 (SMPD1) in complementing model systems.MethodsUsing CRISPR/Cas gene editing, smpd1 mutant (smpd1-/-) zebrafish were generated and crossed to our previously characterised gba1-/- zebrafish line, generating double knockouts (gba1-/-;smpd1-/-). Spontaneous motor behaviour and survival were assessed in WT, single mutants and double mutants. HPLC-based sphingolipid quantification was combined with RNAseq based pathway analysis, assessment of the mitochondrial respiratory chain and quantification of lipid membrane oxidation for in-depth assessment of cellular health across all four genotypes. We also determined the effect of combined glucocerebrosidase (GCase) and acid sphingomyelinase (ASM) inactivation on autophagy and alpha-synuclein homeostasis in the human neuronal cell line SH-SY5Y.ResultsUnexpectedly, ASM deficiency rescued the marked behavioural phenotype and prolonged survival in gba1-/-;smpd1-/- double-mutant zebrafish compared to gba1-/-. RNAseq-based pathway analysis confirmed a profound rescue of neuronal function and intracellular homeostasis. We identified complete reciprocal rescue of mitochondrial respiratory chain function and abolished lipid membrane oxidation in gba1-/-;smpd1-/- compared to gba1-/- or smpd1-/- as the underlying rescue mechanism. The complementing in vitro experiments demonstrated an unexpected reduction of α-synuclein levels in human cell lines with combined GCase and ASM deficiency.ConclusionsOur study highlights the importance of functional validation for any putative mechanistic interactions between genetic risk factors and their overall effect on disease-relevant mechanisms rather than readily assuming an additive effect.

Benzo(a)pyrene induces lung toxicity and inflammation in mice: prevention by carvacrol

Benzo(a)pyrene (B(a)P) is an environmental pollutant which causes various lung toxicities. The present study was designed to evaluate the protective effects of carvacrol, a monoterpenic phenol against B(a)P-induced lung toxicity. In this study, Swiss albino mice were pretreated with carvacrol (25 mg/kg and 50 mg/kg) orally for 7 consecutive days before administering oral B(a)P (125 mg/kg). Preventive efficacy of carvacrol was assessed in terms of membrane oxidation, antioxidant enzyme activities, histopathological changes, and inflammatory (iNOS, NF-κB, and COX-2) markers. Carvacrol pretreatment in the two doses restored B(a)P-induced lipid peroxidation and increased the activities of antioxidant enzymes. Protein expressions of iNOS, NF-κB, and COX-2 in the lung tissue were found to be upregulated by B(a)P. Carvacrol treatment, however, downregulated their expressions by decreasing the marker of positive stained cells and restored the histopathological architecture of lung tissue. Our results suggest that carvacrol can be used as a protective agent against B(a)P-induced lung toxicity and inflammation.

IMPACT OF ACTIVE COMPOUNDS ISOLATED FROM BANANA (MUSA SP. VAR. NANJANGUD RASABALE) FLOWER AND PSEUDOSTEM TOWARDS CYTOPROTECTIVE AND DNA PROTECTION ACTIVITIES

Objective: The present study was designed to evaluate for cytoprotective and DNA protective properties of the compounds isolated from ethanol extract of banana flower (EF) and ethanol extract of banana pseudostem (EE).Methods: The four active compounds viz., umbelliferone (C1) andlupeol (C2) from EF and stigmasterol (C3) and β-sitosterol (C4) from EE were isolated by activity-guided repeated fractionation through silica gel column chromatography. The isolated compounds were evaluated for cytoprotective on erythrocytes and pTZ57R/T plasmid DNA protection against hydroxyl radicals.Results: The study revealed that the compounds (C1-C4) at a concentration of 1 mg/ml exhibited 90% protection on erythrocytes membrane oxidation and also protect the pTZ57R/T plasmid DNA damage induced by hydroxyl radicals.Conclusion: These results endorse an insight for a strong chemical basis to the alleged beneficial role of EF and EE in reducing oxidative stress conditions.