Mitochondria are highly dynamic, maternally inherited cytoplasmic organelles, which fulfill cellular energy demand through the oxidative phosphorylation system. Besides, they play an active role in ...calcium and damage‐associated molecular patterns signaling, amino acid, and lipid metabolism, and apoptosis. Thus, the maintenance of mitochondrial integrity and homeostasis is extremely critical, which is achieved through continual fusion and fission. Mitochondrial fusion allows the transfer of gene products between mitochondria for optimal functioning, especially under metabolic and environmental stress. On the other hand, fission is crucial for mitochondrial division and quality control. The imbalance between these two processes is associated with various ailments such as cancer, neurodegenerative and cardiovascular diseases. This review discusses the molecular mechanisms that control mitochondrial fusion and fission and how the disruption of mitochondrial dynamics manifests into various disease conditions.
Exosomes have received significant attention for their role in pathobiological processes and are being explored as a tool for disease diagnosis and management. Consequently, various isolation methods ...based on different principles have been developed for exosome isolation. Here we compared the efficacy of four kits from Invitrogen, 101Bio, Wako and iZON along with conventional ultracentrifugation-based method for exosome yield, purity and quality. Cell culture supernatant was used as an abundant source of exosomes, and exosome quantity, size-distribution, zeta-potential, marker-expression and RNA/protein quality were determined. The Invitrogen kit gave the highest yield but the preparation showed broader size-distribution likely due to microvesicle co-precipitation and had the least dispersion stability. Other preparations showed <150 nm size range and good stability. Preparation from iZON column; however, had a broader size-distribution in the lower size range suggestive of some impurities of non-vesicular aggregates. RNA quality from all preparations was comparable; however, proteins from Invitrogen method-based exosomal preparation showed polyethylene glycol (PEG) contamination in mass spectrometry. Chemical impurities from the precipitant could also be the cause of toxicity of Invitrogen method-based exosomal preparation in biological growth measurement assay. Together, these findings should serve as a guide to choose and further optimize exosome isolation methods for their desired downstream applications.
Engineering is traditionally considered a male domain with lower female participation despite various affirmative actions taken in recent decades. There is evidence of greater gender equality as a ...result of the COVID-19 pandemic and precautionary lockdown measures. With this in mind, this paper investigates whether women engineers in India were more adversely affected than their male counterparts by the COVID-19 pandemic. Such an impact may be explained by ‘intersectional stigma’, expanded upon in the literature on discrimination. The impact of such stigma varies in different countries based on socio-cultural factors. Through the use of ethnographic and statistical research methods on secondary and primary data from a sample of 384 engineers, this paper shows that the impact of COVID-19 is not significantly different between genders in engineering education and employment. This may be due to the high demand for digital engineering skills, and strong family support in Indian society. Engineering branch may play a relatively more important role than gender in terms of impact. This finding has repercussions for continuing engineering education (CEE) programs and regulatory bodies in India in terms of enhancing course content and the results may be used in developing affirmative programs in other regions.
In future biorefineries, the development of inexpensive and renewable reagents is highly desirable. In this work, we report a renewable and new class of deep eutectic solvent (DES) synthesized from ...lignin-derived phenolic compounds. Novel DESs tested in this work showed their potential as solvents for biomass pretreatment in terms of lignin removal and sugar release after enzymatic saccharification. The recycling and reusability of DESs were also evaluated. The results from this study prove that DESs synthesized from renewable resources are promising solvents for future biorefineries.
As the attraction of creating biofuels and bio-based chemicals from lignocellulosic biomass has increased, researchers have been challenged with developing a better understanding of lignin structure, ...quantity and potential uses. Lignin has frequently been considered a waste-product from the deconstruction of plant cell walls, in attempts to isolate polysaccharides that can be hydrolyzed and fermented into fuel or other valuable commodities. In order to develop useful applications for lignin, accurate analytical instrumentation and methodologies are required to qualitatively and quantitatively assess, for example, what the structure of lignin looks like or how much lignin comprises a specific feedstock׳s cellular composition. During the past decade, various diverse strategies have been employed to elucidate the structure and composition of lignin. These techniques include using two-dimensional nuclear magnetic resonance to resolve overlapping spectral data, measuring biomass with vibrational spectroscopy to enable modeling of lignin content or monomeric ratios, methods to probe and quantify the linkages between lignin and polysaccharides, or refinements of established methods to provide higher throughput analyses, less use of consumables, etc. This review seeks to provide a comprehensive overview of many of the advancements achieved in evaluating key lignin attributes. Emphasis is placed on research endeavored in the last decade.
The efficiency of two biomass pretreatment technologies, dilute acid hydrolysis and dissolution in an ionic liquid, are compared in terms of delignification, saccharification efficiency and ...saccharide yields with switchgrass serving as a model bioenergy crop. When subject to ionic liquid pretreatment (dissolution and precipitation of cellulose by anti-solvent) switchgrass exhibited reduced cellulose crystallinity, increased surface area, and decreased lignin content compared to dilute acid pretreatment. Pretreated material was characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and chemistry methods. Ionic liquid pretreatment enabled a significant enhancement in the rate of enzyme hydrolysis of the cellulose component of switchgrass, with a rate increase of 16.7-fold, and a glucan yield of 96.0% obtained in 24h. These results indicate that ionic liquid pretreatment may offer unique advantages when compared to the dilute acid pretreatment process for switchgrass. However, the cost of the ionic liquid process must also be taken into consideration.
Auto-fluorescent mapping of plant cell walls was used to visualize cellulose and lignin in pristine switchgrass (Panicum virgatum) stems to determine the mechanisms of biomass dissolution during ...ionic liquid pretreatment. The addition of ground switchgrass to the ionic liquid 1-n-ethyl-3-methylimidazolium acetate resulted in the disruption and solubilization of the plant cell wall at mild temperatures. Swelling of the plant cell wall, attributed to disruption of inter- and intramolecular hydrogen bonding between cellulose fibrils and lignin, followed by complete dissolution of biomass, was observed without using imaging techniques that require staining, embedding, and processing of biomass. Subsequent cellulose regeneration via the addition of an anti-solvent, such as water, was observed in situ and provided direct evidence of significant rejection of lignin from the recovered polysaccharides. This observation was confirmed by chemical analysis of the regenerated cellulose. In comparison to untreated biomass, ionic liquid pretreated biomass produces cellulose that is efficiently hydrolyzed with commercial cellulase cocktail with high sugar yields over a relatively short time interval.
Liver cell death has an essential role in nonalcoholic steatohepatitis (NASH). The activity of the energy sensor adenosine monophosphate (AMP)-activated protein kinase (AMPK) is repressed in NASH. ...Liver-specific AMPK knockout aggravated liver damage in mouse NASH models. AMPK phosphorylated proapoptotic caspase-6 protein to inhibit its activation, keeping hepatocyte apoptosis in check. Suppression of AMPK activity relieved this inhibition, rendering caspase-6 activated in human and mouse NASH. AMPK activation or caspase-6 inhibition, even after the onset of NASH, improved liver damage and fibrosis. Once phosphorylation was decreased, caspase-6 was activated by caspase-3 or -7. Active caspase-6 cleaved Bid to induce cytochrome c release, generating a feedforward loop that leads to hepatocyte death. Thus, the AMPK-caspase-6 axis regulates liver damage in NASH, implicating AMPK and caspase-6 as therapeutic targets.
Cellulose is inherently resistant to breakdown, and the native crystalline structure (cellulose I) of cellulose is considered to be one of the major factors limiting its potential in terms of ...cost-competitive lignocellulosic biofuel production. Here we report the impact of ionic liquid pretreatment on the cellulose crystalline structure in different feedstocks, including microcrystalline cellulose (Avicel), switchgrass ( Panicum virgatum ), pine ( Pinus radiata ), and eucalyptus ( Eucalyptus globulus ), and its influence on cellulose hydrolysis kinetics of the resultant biomass. These feedstocks were pretreated using 1-ethyl-3-methyl imidazolium acetate (C2mimOAc) at 120 and 160 °C for 1, 3, 6, and 12 h. The influence of the pretreatment conditions on the cellulose crystalline structure was analyzed by X-ray diffraction (XRD). On a larger length scale, the impact of ionic liquid pretreatment on the surface roughness of the biomass was determined by small-angle neutron scattering (SANS). Pretreatment resulted in a loss of native cellulose crystalline structure. However, the transformation processes were distinctly different for Avicel and for the biomass samples. For Avicel, a transformation to cellulose II occurred for all processing conditions. For the biomass samples, the data suggest that pretreatment for most conditions resulted in an expanded cellulose I lattice. For switchgrass, first evidence of cellulose II only occurred after 12 h of pretreatment at 120 °C. For eucalyptus, first evidence of cellulose II required more intense pretreatment (3 h at 160 °C). For pine, no clear evidence of cellulose II content was detected for the most intense pretreatment conditions of this study (12 h at 160 °C). Interestingly, the rate of enzymatic hydrolysis of Avicel was slightly lower for pretreatment at 160 °C compared with pretreatment at 120 °C. For the biomass samples, the hydrolysis rate was much greater for pretreatment at 160 °C compared with pretreatment at 120 °C. The result for Avicel can be explained by more complete conversion to cellulose II upon precipitation after pretreatment at 160 °C. By comparison, the result for the biomass samples suggests that another factor, likely lignin−carbohydrate complexes, also impacts the rate of cellulose hydrolysis in addition to cellulose crystallinity.
Studies were conducted for understanding the electrochemical (EC) degradation mechanism of a triphenylmethane dye, namely, basic green 4 (BG), commonly known as malachite green with aluminum ...electrode. At the optimum conditions (current density = 117.64 A m–2, initial dye concentration = 125 mg L–1, pH = 6.5, electrode gap = 1 cm, and NaCl concentration = 1.5 g L–1), more than 85% BG degradation was observed within 50 min of treatment. UV–visible and Fourier transform infrared (FTIR) spectroscopy, high performance liquid chromatography (HPLC), gas chromatography–mass spectroscopy (GCMS), and high-resolution mass spectroscopy (HRMS) analysis showed that the degradation occurred via the cleavage of conjugated structure and N-demethylation. The intermediate products identified included hydroxymethylated intermediates during the N-demethylation of the dye; and N,N,N′,N′-tetramethyl-4,4′-diaminobenzophenone, 4,4′-bisaminobenzophenone and N-methyl-para-aminophenol after cleavage of the conjugated triphenylmethane ring. Zeta potential study indicated a hard acid–base interaction between aluminum ions and hydroxides generated in situ during the EC treatment process and the −N(CH3)2 group of dye molecules. Generation of active species such as hydrogen peroxide, ozone, and chlorinated oxidizing compounds was observed during the EC treatment process and that the BG degradation occurred via a •OH radical attack.
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