An alternative physiological role for the EmhABC efflux pump in Pseudomonas fluorescens cLP6a

<p>Abstract</p> <p>Background</p> <p>Efflux pumps belonging to the resistance-nodulation-division (RND) superfamily in bacteria are involved in antibiotic resistance and solvent tolerance but have an unknown physiological role. EmhABC, a RND-type efflux pump in <it>Pseudomonas fluorescens </it>strain cLP6a, extrudes hydrophobic antibiotics, dyes and polycyclic aromatic hydrocarbons including phenanthrene. The effects of physico-chemical factors such as temperature or antibiotics on the activity and expression of EmhABC were determined in order to deduce its physiological role(s) in strain cLP6a in comparison to the <it>emhB </it>disruptant strain, cLP6a-1.</p> <p>Results</p> <p>Efflux assays conducted with ¹⁴C-phenanthrene showed that EmhABC activity is affected by incubation temperature. Increased phenanthrene efflux was measured in cLP6a cells grown at 10°C and decreased efflux was observed at 35°C compared with cells grown at the optimum temperature of 28°C. Membrane fatty acids in cLP6a cells were substantially altered by changes in growth temperature and in the presence of tetracycline. Changed membrane fatty acids and increased membrane permeability were associated with ~30-fold increased expression <it>of emhABC </it>in cLP6a cells grown at 35°C, and with increased extracellular free fatty acids. Growth <it>of P. fluorescens </it>cLP6a at supra-optimal temperature was enhanced by the presence of EmhABC compared to strain cLP6a-1.</p> <p>Conclusions</p> <p>Combined, these observations suggest that the EmhABC efflux pump may be involved in the management of membrane stress effects such as those due to unfavourable incubation temperatures. Efflux of fatty acids replaced as a result of membrane damage or phospholipid turnover may be the primary physiological role of the EmhABC efflux pump in <it>P. fluorescens </it>cLP6a.</p

Synthesis and Characterization of Zinc Oxide Nanoparticle for the Adsorptive Remediation of Petrochemical Effluents

The zinc oxide nanoparticle was synthesized via precipitation method. It was characterized using SEM-EDX, FTIR and TEM for morphology, elemental, functional groups and internal structure respectively. The physicochemical behaviour of a refinery effluent was assessed. The untreated raw refinery effluent from the point of discharge contained very high concentrations of pollutants for all the parameters, ranging between, pH (6.52-6.82), Turbidity (10-12 NTU), conductivity (266-289μs/cm), COD (116-138 mg/l), BOD (14-18.5 mg/l), DO (7.5-15.6 mg/l), TDS (436-486 mg/l), TSS (127-133 mg/l), Oil and grease (14.8-16.3 mg/l), sulphate (113-125 mg/l) and chloride (240-280 mg/l). The effluent was treated with ZnO nanoparticle and reduced the pollutants to the normal permissible limit set by WHO, FEPA and NESREA standard for portable water. The treated effluent sample showed values ranging between, pH (6.55-6.6), Turbidity (4.2-4.5 NTU), conductivity (245-246 μs/cm), COD (39-40 mg/l), BOD (10 mg/l), DO (5.6-10.4 mg/l), TDS (151-183 mg/l), TSS (24-28 mg/l), Oil and grease (7.3-9.5 mg/l), sulphate (100 mg/l) and chloride (200 mg/l). The heavy metals profile that was investigated are Fe, Cu, Zn, Pb, Cd and Cr of which were found above the WHO and FEPA permissible limit, however, on the contact with the adsorbent therefore reduced the metals to the permissible limit. It can be ascertain that ZnO nanoparticle can be used as an effective adsorbent for the treatment of petrochemical effluent

Discovery of Clioquinol and analogues as novel inhibitors of Severe Acute Respiratory Syndrome Coronavirus 2 infection, ACE2 and ACE2 - Spike protein interaction in vitro

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the etiological agent for coronavirus disease 2019 (COVID-19), has resulted in an ongoing pandemic. Presently, there are no clinically approved drugs for COVID-19. Hence, there is an urgent need to accelerate the development of effective antivirals. Herein, we discovered Clioquinol (5-chloro-7-iodo-8-quinolinol (CLQ)), a Food and Drug Administration (FDA) approved drug, and two of its analogues (7-bromo-5-chloro-8-hydroxyquinoline (CLBQ14); and 5, 7-Dichloro-8-hydroxyquinoline (CLCQ)) as potent inhibitors of SARS-CoV-2 infection-induced cytopathic effect in vitro. In addition, all three compounds showed potent anti-exopeptidase activity against recombinant human angiotensin-converting enzyme 2 (rhACE2) and inhibited the binding of rhACE2 with SARS-CoV-2 Spike (RBD) protein. CLQ displayed the highest potency in the low micromolar range, with its antiviral activity showing a strong correlation with inhibition of rhACE2 and rhACE2-RBD interaction. Altogether, our findings provide a new mode of action and molecular target for CLQ and validates this pharmacophore as a promising lead series for the clinical development of potential therapeutics for COVID-19

Metabolic Alterations in Different Stages of Hypertension in an Apparently Healthy Nigerian Population

Metabolic syndrome (MS) amplifies hypertension (HTN) associated with increased risk of cardiovascular disease (CVD). MS components and other CVD risk measures were investigated in different stages of hypertension. 534 apparently healthy Nigerian traders aged 18–105 years were participants of a cohort study. The International Diabetes Federation (2005) and the National High Blood Pressure Education Program Coordinating Committee criteria were used for MS and HTN classifications, respectively. Anthropometric indices were obtained by standard methods. Levels of fasting plasma glucose (FPG), total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDLC) were determined by enzymatic methods, while low-density lipoprotein cholesterol (LDLC) was calculated. Data analysed statistically were significant at P<0.05. 143 (26.8%), 197 (36.9%), and 194 (36.3%) of the traders had normotension, pre-HTN and HTN (stages 1 and 2), respectively. All indices tested except HDLC were significantly different among BP groups (P<0.05). Waist to hip (WHR) and waist to height (WHT) ratios were significantly different between HTN groups (P<0.05). HTN was associated with MS and female gender (P<0.05). Metabolic alterations and significant HTN were observed. Treatment of the individual components of the syndrome and improvement of modifiable metabolic factors may be necessary to reduce MS and high BP