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Polyhydroxyalkanoates (PHAs) are synthesized by a variety of microorganisms as intracellular storage granules under imbalanced nutrition and excess carbon. Carbon sources are key contributors to the high cost of PHA production, hence the need for exploration of cheap and sustainable raw materials for bacteria fermentation. In the present study, Halomonas alkalicola strain Ext isolated from a hypersaline lake in Kenya was assessed for its ability to utilize fruit peels hydrolysates (FPH) as sole carbon sources for PHA production. Sugars were extracted from dried peels of banana, mango, orange, and pineapple fruits through mechanical pretreatment and dilute acid hydrolysis. Fruit peels pretreated with 3 % H2SO4 at 121℃ were utilized for shake flask fermentation to produce PHAs by Halomonas alkalicola Ext. At optimal C:N ratios of between 20:1 and 30:1, the bacterium could produce up to 0.45±0.03, 0.394±0.12, 0.39±0.05, and 0.28±0.0 g/L of PHAs from hydrolysates of orange peels, mango peels, banana peels, and pineapple peels, respectively. A maximum PHA content of 16.92 % was achieved on orange peels hydrolysates with 4 % substrate loading. Monomer analysis with gas chromatography-mass spectrometry (GC-MS) revealed that the bacterium produced a copolymer Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with 3-hydroxyvalerate (3HV) contents of 5.77 %, 6.08 %, 6.79 %, 6.845 %, for orange peels, pineapple peels, mango peels and banana peels substrates, respectively. The findings of this study suggest that fruit peels waste is a potential feedstock for sustainable production of PHAs by Halomonas alkalicola.

Natural proteinaceous pore-forming agents can bind and permeabilize cell membranes, leading to ion dyshomeostasis and cell death. In the search for antidotes that can protect cells from peptide toxins, we discovered that the polyphenol epigallocatechin gallate (EGCG) interacts directly with melittin from honeybee venom, resulting in the elimination of its binding to the cell membrane and toxicity by markedly lowering the extent of its solvent-exposed hydrophobicity and promoting its oligomerization into larger species. These physicochemical parameters have also been shown to play a key role in the binding to cells of misfolded protein oligomers in a host of neurodegenerative diseases, where oligomer-membrane binding and associated toxicity have been shown to correlate negatively with oligomer size and positively with solvent-exposed hydrophobicity. For melittin, which is not an amyloid-forming protein and has a very distinct mechanism of toxicity compared to misfolded oligomers, we find that the size-hydrophobicity-toxicity relationship also rationalizes the pharmacological attenuation of melittin toxicity by EGCG. These results highlight the importance of the physicochemical properties of pore forming agents in mediating their interactions with cell membranes and suggest a possible therapeutic approach based on compounds with a similar mechanism of action as EGCG., (Published by Elsevier B.V.)

Objective: The main objective of this study was to investigate the association between alcohol consumption (use and bingeing) and the desire to own a firearm for protection., Study Design: We used data from three random cross-sectional victimisation surveys conducted in São Paulo city, Brazil, in 2003, 2008 and 2013 with people aged ≥16 years., Methods: We performed tests for equality of proportions. Our analysis was performed separately for each victimisation survey to check the robustness of the results. We also used probit models, estimated by the maximum likelihood method, to analyse the relationship between desire to own a firearm and alcohol consumption, controlling for many other variables., Results: In 2013, although only 1.5% of the population surveyed reported living in a household with a firearm, 15.7% report that they would possess a firearm if they could, and 13.0% believed they would be safer/more protected from violence if they had a firearm. The desire to own a firearm is higher among people who consume alcoholic beverages than among those who do not and is higher as alcohol binge frequency increases., Conclusion: In São Paulo city, alcohol consumption and binge drinking are positively associated with the desire to own a firearm., (Copyright © 2019 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.)

Atrial fibrillation (AF) is by far the most common sustained tachyarrhythmia, affecting 1% to 2% of the general population. AF prevalence and the total annual cost for treatment are alarming, emphasizing the need for an urgent attention to the problem. Thus, having up-to-date information on AF risk factors and appreciating how they promote maintenance of AF maintenance are essential. This article presents a simplified examination of AF risk factors, including emerging genetic risks., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Persistent atrial fibrillation (PAF) results in electromechanical and structural remodeling by mechanisms that are poorly understood. Myofibroblast proliferation and fibrosis are major sources of structural remodeling in PAF. Myofibroblasts also interact with atrial myocytes via direct physical contact and release of signaling molecules, which may contribute to remodeling., Objective: To determine whether myofibroblasts contribute to atrial myocyte electromechanical remodeling via direct physical contact and platelet-derived growth factor (PDGF) signaling., Methods: Myofibroblasts and myocytes from adult sheep atria were co-cultured for 24 hours. Alternatively adult sheep atrial myocytes were exposed to 1 ng/mL recombitant PDGF AB peptide for 24 hours., Results: Myocytes making contact with myofibroblasts demonstrated significant reduction (P ≤ .05) in peak L-type calcium current density, shortening of action potential duration (APD), and reduction in calcium transients. These effects were blocked by pretreatment with a PDGF-AB neutralizing anti-body. Heterocellular contact also severely disturbed the localization of the L-type calcium channel. Myocytes exposed to recombinant PDGF-AB peptide for 24 hours demonstrated reduced APD50, APD80 and Peak L-type calcium current. Pretreatment with a PDGF-AB neutralizing antibody prevented these effects. Finally, while control atrial myocytes did not respond in a 1:1 manner to pacing frequencies of 3 Hz or higher, atrial myocytes from hearts that were tachypaced for 2 months and normal myocytes treated with PDGF-AB for 24 hours could be paced up to 10 Hz., Conclusions: In addition to leading to fibrosis, atrial myofibroblasts contribute to electromechanical remodeling of myocytes via direct physical contact and release of PDGF-AB, which may be a factor in PAF-induced remodeling., (Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Collecting electrophysiological and molecular data from the murine conduction system presents technical challenges. Thus, only little advantage has been taken of numerous genetically engineered murine models to study excitation through the cardiac conduction system of the mouse., Objective: To develop an approach for isolating murine cardiac Purkinje cells (PCs), to characterize major ionic currents and to use the data to simulate action potentials (APs) recorded from PCs., Methods: Light microscopy was used to isolate and identify PCs from apical and septal cells. Current and voltage clamp techniques were used to record APs and whole cell currents. We then simulated a PC AP on the basis of our experimental data., Results: APs recorded from PCs were significantly longer than those recorded from ventricular cells. The prominent plateau phase of the PC AP was very negative (≈-40 mV). Spontaneous activity was observed only in PCs. The inward rectifier current demonstrated no significant differences compared to ventricular myocytes (VMs). However, sodium current density was larger, and the voltage-gated potassium current density was significantly less in PCs compared with myocytes. T-type Ca(2+) currents (I(Ca,T)) were present in PCs but not VMs. Computer simulations suggest that I(Ca,T) and cytosolic calcium diffusion significantly modulate AP profile recorded in PCs, as compared to VMs., Conclusions: Our study provides the first comprehensive ionic profile of murine PCs. The data show unique features of PC ionic mechanisms that govern its excitation process. Experimental data and numerical modeling results suggest that a smaller voltage-gated potassium current and the presence of I(Ca,T) are important determinants of the longer and relatively negative plateau phase of the APs., (Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Sodium channel α-subunits in ventricular myocytes (VMs) segregate either to the intercalated disc or to lateral membranes, where they associate with region-specific molecules., Objective: To determine the functional properties of sodium channels as a function of their location in the cell., Methods: Local sodium currents were recorded from adult rodent VMs and Purkinje cells by using the cell-attached macropatch configuration. Electrodes were placed either in the cell midsection (M) or at the cell end (area originally occupied by the intercalated disc [ID]). Channels were identified as tetrodotoxin (TTX)-sensitive (TTX-S) or TTX-resistant (TTX-R) by application of 100 nM of TTX., Results: Average peak current amplitude was larger in ID than in M and largest at the site of contact between attached cells. TTX-S channels were found only in the M region of VMs and not in Purkinje myocytes. TTX-R channels were found in both M and ID regions, but their biophysical properties differed depending on recording location. Sodium current in rat VMs was upregulated by tumor necrosis factor-alpha. The magnitude of current increase was largest in the M region, but this difference was abolished by application of 100 nM of TTX., Conclusions: Our data suggest that (a) a large fraction of TTX-R (likely Na(v)1.5) channels in the M region of VMs are inactivated at normal resting potential, leaving most of the burden of excitation to TTX-R channels in the ID region; (b) cell-cell adhesion increases functional channel density at the ID; and (c) TTX-S (likely non-Na(v)1.5) channels make a minimal contribution to sodium current under control conditions, but they represent a functional reserve that can be upregulated by exogenous factors., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Data on pH regulation of the cardiac potassium current I(K1) suggest species-dependent differences in the molecular composition of the underlying Kir2 channel proteins., Objective: The purpose of this study was to test the hypothesis that the presence of the Kir2.3 isoform in heterotetrameric channels modifies channel sensitivity to pH., Methods: Voltage clamp was performed on HEK293 cells stably expressing guinea pig Kir2.1 and/or Kir2.3 isoforms and on sheep cardiac ventricular myocytes at varying extracellular pH (pH(o)) and in the presence of CO(2) to determine the sensitivity of macroscopic currents to pH. Single-channel activity was recorded from the HEK293 stables to determine the mechanisms of the changes in whole cell current., Results: Biophysical characteristics of whole-cell and single-channel currents in Kir2.1/Kir2.3 double stables displayed properties attributable to isoform heteromerization. Whole-cell Kir2.1/Kir2.3 currents rectified in a manner reminiscent of Kir2.1 but were significantly inhibited by extracellular acidification in the physiologic range (pK(a) approximately 7.4). Whole-cell currents were more sensitive to a combined extracellular and intracellular acidification produced by CO(2). At pH(o) = 6.0, unitary conductances of heteromeric channels were reduced. Ovine cardiac ventricular cell I(K1) was pH(o) and CO(2) sensitive, consistent with the expression of Kir2.1 and Kir2.3 in this species., Conclusion: Kir2.1 and Kir2.3 isoforms form heteromeric channels in HEK293. The presence of Kir2.3 subunit(s) in heteromeric channels confers pH sensitivity to the channels. The single and double stable cells presented in this study are useful models for studying physiologic regulation of heteromeric Kir2 channels in mammalian cells.

The mouse Nkx-5.1 and Nkx-5.2 genes have been identified by sequence homology to Drosophila NK genes within the homeobox domain. Here, we report the isolation of the Nkx-5.2 cDNA and a detailed comparative analysis of the spatio-temporal expression patterns for Nkx-5.1 and Nkx-5.2 genes. Nkx-5.2 transcripts are first detected in E13.5 embryos where they colocalize with Nkx-5.1 mRNA in the developing central nervous system and the inner ear. However, the onset of Nkx-5.1 transcription begins much earlier in 10 somite stage embryos (E8.5) in the otic placode and the branchial region. Nkx-5.1 expression in the ear persists until birth, whereas in branchial arches it is transient between E8.5 to E11.5. Transcript distribution appears regionalized in the otic vesicle concentrating at the anterior and posterior margin and later at the dorsal side of the otocyst. These domains are distinct from regions expressing Pax-2 and sek, two other early markers for otic development. From E11.5 to birth several Nkx-5.1 expression domains appear in the brain between the ventral diencephalon and the myelencephalon. The same expression domains also exist for Nkx-5.2 beginning at E13.5. The regionally restricted expression pattern of both Nkx-5 genes during mouse development suggests their involvement in cell type specification of neuronal cells.