Electron Storage in Electroactive Biofilms ter Heijne, A.; Pereira, M.A.; Pereira, J. ...
Trends in biotechnology,
January 2021, 2021-01-00, 20210101, Letnik:
39, Številka:
1
Journal Article
Recenzirano
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Microbial electrochemical technologies (METs) are promising for sustainable applications. Recently, electron storage during intermittent operation of electroactive biofilms (EABs) has been shown to ...play an important role in power output and electron efficiencies. Insights into electron storage mechanisms, and the conditions under which these occur, are essential to improve microbial electrochemical conversions and to optimize biotechnological processes. Here, we discuss the two main mechanisms for electron storage in EABs: storage in the form of reduced redox active components in the electron transport chain and in the form of polymers. We review electron storage in EABs and in other microorganisms and will discuss how the mechanisms of electron storage can be influenced.
Intermittent operation of bioanodes influences electron storage in the electroactive biofilm.Longer-term electron storage in the carry over of polymers is an unexplored mechanism.Microbial electrochemical technologies are unique because electrodes provide a new way to control biological conversions.Understanding electron storage may provide new ways to influence the selectivity of biotechnological processes.
Over the past decade, there have been an increasing number of studies on the association between vitamin D deficiency and anthropometric state. However, we did not identify any meta‐analyses of the ...relationship between obesity and vitamin D deficiency in different age groups. Thus, we evaluated the association between obesity and vitamin D deficiency. We searched for observational studies published up to April 2014 in PubMed/Medline, Web of Science and Scopus databases. We performed a meta‐analysis in accordance with the random‐effects model to obtain the summary measurement (prevalence ratio, PR). Among the 29,882 articles identified, 23 met the inclusion criteria. The prevalence of vitamin D deficiency was 35% higher in obese subjects compared to the eutrophic group (PR: 1.35; 95% CI: 1.21–1.50) and 24% higher than in the overweight group (PR: 1.24; 95% CI: 1.14–1.34). These results indicate that the prevalence of vitamin D deficiency was more elevated in obese subjects. The vitamin D deficiency was associated with obesity irrespective of age, latitude, cut‐offs to define vitamin D deficiency and the Human Development Index of the study location.
The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method is a simple and straightforward extraction technique involving an initial partitioning followed by an extract clean-up using ...dispersive solid-phase extraction (d-SPE). Originally, the QuEChERS approach was developed for recovering pesticide residues from fruits and vegetables, but rapidly gained popularity in the comprehensive isolation of analytes from different matrices. According to PubMed, since its development in 2003 up to November 2018, about 1360 papers have been published reporting QuEChERS as extraction method. Several papers have reported different improvements and modifications to the original QuEChERS protocol to ensure more efficient extractions of pH-dependent analytes and to minimize the degradation of labile analytes. This analytical approach shows several advantages over traditional extraction techniques, requiring low sample and solvent volumes, as well as less time for sample preparation. Furthermore, most of the published studies show that the QuEChERS protocol provides higher recovery rate and a better analytical performance than conventional extraction procedures.
This review proposes an updated overview of the most recent developments and applications of QuEChERS beyond its original application to pesticides, mycotoxins, veterinary drugs and pharmaceuticals, forensic analysis, drugs of abuse and environmental contaminants. Their pros and cons will be discussed, considering the factors influencing the extraction efficiency. Whenever possible, the performance of the QuEChERS is compared to other extraction approaches. In addition to the evolution of this technique, changes and improvements to the original method are discussed.
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•Modification and miniaturization of QuEChERS method.•An updated overview of the most recent QuEChERS applications.•QuEChERS combined with GC- and LC-MS/MS provided low detection limits and high recoveries.•QuEChERS performance compared to other extraction approaches.
The purpose of this study was to evaluate the influence of adding Lactobacillus acidophilus to a triple regimen for Helicobacter pylori eradication in untreated patients with peptic ulcers or ...ulcer-scars. This was a pre-randomized, single-blind, interventional, treatment-efficacy study with active controls and parallel-assignment, set in Coimbra, Portugal, on 62 consecutive H. pylori-positive untreated adults with peptic ulcers or ulcer-scars, diagnosed by gastroduodenoscopy, with pre-treatment direct Gram-staining and culture of gastric biopsies. The first 31 patients received esomeprazole 20 mg, amoxicillin 1000 mg and clarithromycin 500 mg (EAC), all b.i.d., for 8 days. The remaining 31 added L. acidophilus, 5 × 10⁹ organisms per capsule, 3 + 2 i.d. for 8 days (EACL). The main outcome measure was ¹³C urea breath test (UBT), ≥6 weeks after completion of therapy. Successful eradication (UBT-negativity after treatment), was similar in both groups (EAC = 80.6%; EACL = 83.9%, p = 0.740) by both intention-to-treat and per-protocol analysis. The non-eradicated strains were susceptible in vitro to both antibiotics. Adding L. acidophilus to EAC triple therapy did not increase H. pylori eradication rates. Considering the cost and the burden of ingesting five extra capsules daily, supplementing the EAC therapy with L. acidophilus, at this dose, shows no benefit. Further studies with different dosages and duration of treatment, and other probiotics or probiotic combinations are required to improve eradication.
This work evaluated the removal of a mixture of eight antibiotics (i.e. ampicillin (AMP), azithromycin (AZM), erythromycin (ERY), clarithromycin (CLA), ofloxacin (OFL), sulfamethoxazole (SMX), ...trimethoprim (TMP) and tetracycline (TC)) from urban wastewater, by ozonation operated in continuous mode at different hydraulic retention times (HRTs) (i.e. 10, 20, 40 and 60 min) and specific ozone doses (i.e. 0.125, 0.25, 0.50 and 0.75 gO3 gDOC− 1). As expected, the efficiency of ozonation was highly ozone dose- and contact time-dependent. The removal of the parent compounds of the selected antibiotics to levels below their detection limits was achieved with HRT of 40 min and specific ozone dose of 0.125 gO3 gDOC− 1. The effect of ozonation was also investigated at a microbiological and genomic level, by studying the efficiency of the process with respect to the inactivation of Escherichia coli and antibiotic-resistant E. coli, as well as to the reduction of the abundance of selected antibiotic resistance genes (ARGs). The inactivation of total cultivable E. coli was achieved under the experimental conditions of HRT 40 min and 0.25 gO3 gDOC−1, at which all antibiotic compounds were already degraded. The regrowth examinations revealed that higher ozone concentrations were required for the permanent inactivation of E. coli below the Limit of Quantification (<LOQ = 0.01 CFU mL− 1). Also, the abundance of the examined ARGs (intl1, aadA1, dfrA1, qacEΔ1 and sul1) was found to decrease with increasing HRT and ozone dose. Despite the fact that the mildest operating parameters were able to eliminate the parent compounds of the tested antibiotics in wastewater effluents, it was clearly demonstrated in this study that higher ozone doses were required in order to confer permanent damage and/or death and prevent potential post-treatment re-growth of both total bacteria and ARB, and to reduce the abundance of ARGs below the LOQ. Interestingly, the mineralization of wastewater, in terms of Dissolved Organic Carbon (DOC) removal, was found to be significantly low even when the higher ozone doses were applied, leading to an increased phytotoxicity towards various plant species. The findings of this study clearly underline the importance of properly optimising the ozonation process (e.g. specific ozone dose and contact time) taking into consideration both the bacterial species and associated ARGs, as well as the wastewater physicochemical properties (e.g. DOC), in order to mitigate the spread of ARB&ARGs, as well as to reduce the potential phytotoxicity.
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•The antibiotics examined were eliminated under the mildest operating conditions.•Total and antibiotic-resistant E. coli were inactivated after 40 min at low O3 dose.•The ARGs abundance was found to decrease with increasing contact time and O3 dose.•Mineralization was found to be significantly low.•Resulting phytotoxicity can be attributed to the dEfOM and its oxidation products.
Antimicrobial resistance is a major public health concern, particularly in hospitals and other healthcare settings. For the rational design of disinfection strategies, it is of utmost importance to ...understand the mechanisms of action of antimicrobials. In this study, the mechanism of action of benzyldimethyldodecylammonium chloride (BDMDAC) was assessed against Pseudomonas fluorescens.
The targets of antimicrobial action were studied using different bacterial physiological indices. The MIC, MBC, membrane permeabilization, intracellular potassium release, physico-chemical surface properties, surface charge, outer membrane protein (OMP) expression and morphological changes were assessed after BDMDAC exposure.
The MIC was found to be 20 mg/L and the MBC was 10 mg/L. BDMDAC led to a significant change in cell surface hydrophobicity and induced propidium iodide uptake. Such results suggest cytoplasmic membrane damage, corroborated by the release of intracellular potassium. The results obtained from the zeta potential measurement demonstrate a -31.2 mV value for untreated cells and -21.0 mV for cells at the MIC. Scanning electron microscopy revealed that cells treated with 20 mg/L were less bulky, and their membrane seemed to be rougher, wrinkled and deformed when compared with untreated cells. The overall bactericidal events occurred without detectable changes in OMP expression.
BDMDAC is an effective biocide against P. fluorescens. It binds by ionic and hydrophobic interactions to the cell membrane, causing changes in membrane properties and function, as manifested by phenomena such as cellular disruption and loss of membrane integrity with consequent leakage of essential intracellular constituents.
Two air-stable, isostructural, mononuclear six-coordinate manganese(II) and cobalt(II) oxamate complexes, M(4-HOpa)2(H2O)2 4-HOpa = N-4-hydroxyphenyloxamate; M= Mn2+ (1) or Co2+ (2), exhibit ...field-induced slow magnetic relaxation. A bottleneck process is observed throughout the temperature range of 2–20 K for 1, while for 2, it dominates only at low temperatures (2–4 K). Additionally, the Raman process n = 6.9(2) is responsible for an increase in the relaxation time at higher temperatures to 2.
Leptin is a hormone produced by the adipose tissue that acts in the brain, stimulating white fat breakdown. We find that the lipolytic effect of leptin is mediated through the action of sympathetic ...nerve fibers that innervate the adipose tissue. Using intravital two-photon microscopy, we observe that sympathetic nerve fibers establish neuro-adipose junctions, directly “enveloping” adipocytes. Local optogenetic stimulation of sympathetic inputs induces a local lipolytic response and depletion of white adipose mass. Conversely, genetic ablation of sympathetic inputs onto fat pads blocks leptin-stimulated phosphorylation of hormone-sensitive lipase and consequent lipolysis, as do knockouts of dopamine β-hydroxylase, an enzyme required for catecholamine synthesis. Thus, neuro-adipose junctions are necessary and sufficient for the induction of lipolysis in white adipose tissue and are an efferent effector of leptin action. Direct activation of sympathetic inputs to adipose tissues may represent an alternative approach to induce fat loss, circumventing central leptin resistance.
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•The neuro-adipose junction in white adipose tissue is visualized in vivo•Adipocyte-projecting neurons can completely envelop an adipocyte•Leptin stimulates lipolysis via sympathetic neurons in fat•Optogenetic activation of sympathetic fibers in fat drives lipolysis and fat mass reduction
The lipolytic effect of leptin is mediated by sympathetic neurons that innervate adipocytes, forming neuro-adipose junctions that directly mediate fat breakdown. Anti-obesity strategies targeting the sympathetic neurons in fat have the potential to circumvent central leptin resistance.
Summary
What is known and objective
Cannabidiol (CBD) is the main non‐psychotropic component of the Cannabis sativa plant. REM sleep behaviour disorder (RBD) is a parasomnia characterized by the loss ...of muscle atonia during REM sleep associated with nightmares and active behaviour during dreaming. We have described the effects of CBD in RBD symptoms in patients with Parkinson's disease.
Cases summary
Four patients treated with CBD had prompt and substantial reduction in the frequency of RBD‐related events without side effects.
What is new and conclusion
This case series indicates that CBD is able to control the symptoms of RBD.
Activation of Agouti-Related Peptide (AgRP)-expressing neurons promotes feeding and insulin resistance. Here, we examine the contribution of neuropeptide Y (NPY)-dependent signaling to the diverse ...physiological consequences of activating AgRP neurons. NPY-deficient mice fail to rapidly increase food intake during the first hour of either chemo- or optogenetic activation of AgRP neurons, while the delayed increase in feeding is comparable between control and NPY-deficient mice. Acutely stimulating AgRP neurons fails to induce systemic insulin resistance in NPY-deficient mice, while increased locomotor activity upon AgRP neuron stimulation in the absence of food remains unaffected in these animals. Selective re-expression of NPY in AgRP neurons attenuates the reduced feeding response and reverses the protection from insulin resistance upon optogenetic activation of AgRP neurons in NPY-deficient mice. Collectively, these experiments reveal a pivotal role of NPY-dependent signaling in mediating the rapid feeding inducing effect and the acute glucose regulatory function governed by AgRP neurons.
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