Search

Metallic nanoparticles (MeNPs) are widely used in many areas such as biomedicine, packaging, cosmetics, colourants, agriculture, antimicrobial agents, cleaning products, as components of electronic devices and nutritional supplements. In addition, some MeNPs exhibit quantum properties, making them suitable materials in the photonics, electronic and energy industries. Through the lens of technology, microbes can be considered nanofactories capable of producing enzymes, metabolites and capping materials involved in the synthesis, assembly and stabilization of MeNPs. This bioprocess is considered more ecofriendly and less energy intensive than the current chemical synthesis routes. However, microbial synthesis of MeNPs as an alternative method to the chemical synthesis of nanomaterials still faces some challenges that need to be solved. Some of these challenges are described in this Editorial. [ABSTRACT FROM AUTHOR]

Pollution by metalloids, e.g., tellurite and selenite, is of serious environmental concern and, therefore, there is an increasing interest in searching for ecologically friendly solutions for their elimination. Some microorganisms are able to reduce toxic tellurite/selenite into less toxic elemental tellurium (Te) and selenium (Se). Here, we describe the use of the environmentally relevant β‐proteobacterium Aromatoleum sp. CIB as a platform for tellurite elimination. Aromatoleum sp. CIB was shown to tolerate 0.2 and 0.5 mM tellurite at aerobic and anaerobic conditions, respectively. Furthermore, the CIB strain was able to reduce tellurite into elemental Te producing rod‐shaped Te nanoparticles (TeNPs) of around 200 nm length. A search in the genome of Aromatoleum sp. CIB revealed the presence of a gene, AzCIB_0135, which encodes a new methyltransferase that methylates tellurite and also selenite. AzCIB_0135 orthologs are widely distributed in bacterial genomes. The overexpression of the AzCIB_0135 gene both in Escherichia coli and Aromatoleum sp. CIB speeds up tellurite and selenite removal, and it enhances the production of rod‐shaped TeNPs and spherical Se nanoparticles (SeNPs), respectively. Thus, the overexpression of a methylase becomes a new genetic strategy to optimize bacterial catalysts for tellurite/selenite bioremediation and for the programmed biosynthesis of metallic nanoparticles of biotechnological interest. [ABSTRACT FROM AUTHOR]

An efficient and cheap energization of microbial biocatalysts is essential in current biotechnological processes. A promising alternative to the use of common organic or inorganic electron donors is the semiconductor nanoparticles (SNs) that absorb light and transfer electrons (photoelectrons) behaving as artificial photosynthetic systems (biohybrid systems). Excited photoelectrons generated by illuminated SNs are highly reductive and readily accepted by membrane‐bound proteins and electron shuttles to drive specific cell reduction processes and energy generation in microbes. However, the operational mechanisms of these hybrid systems are still poorly understood, especially at the material–microbe interface, and therefore the design and production of efficient biohybrids are challenging. Some major limitations/challenges and future prospects of SNs as microbial energization systems are discussed. [ABSTRACT FROM AUTHOR]

The production of oleic‐based trimethylolpropane (TMP) esters via the esterification reaction between oleic acid (OA) and TMP in a reactive distillation system, employing the environmentally friendly catalyst methanesulfonic acid, was explored. The homogeneous acid catalyst, the OA/TMP molar ratio within 1.0–3.0, the esterification reaction enhancement and a new purification technique, using choline hydroxide (ChOH), for obtaining choline carboxylate as a subproduct, were studied. It was found that using an OA/TMP molar ratio of 3.0, only unreacted OA remained as an impurity. The deleterious or beneficial effect of intermediate products, unreacted OA and temperature on the kinematic viscosity were unraveled. The kinematic viscosity behavior for the products was practically independent of temperature but an abrupt enlargement of the kinematic viscosity was observed in the presence of functional groups in the intermediate esters, even greater than the Mark–Houwink counterpart effect. On contrary, the presence of OA in the final product decreased the kinematic viscosity attending to its lower molecular weight with respect to the trimethylolpropane trioleate one. It was found that trimethylolpropane monooleate is undesirable for the viscosity index, whereas the presence of trimethylolpropane dioleate could also increase the viscosity index to a small extent, requiring a complex purification process. Finally, it is possible to affirm that the optimal TMP‐based lubricant obtained using an OA/TMP molar ratio of 3.0, after OA neutralization presented good marginal benefit and a viscosity index of 208.7, which is applicable for gear lubricants. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 18-year-old woman with fatigue and shortness of breath. Topics include management of symptomatic anemia after presenting to the primary care physician with fatigue and shortness of breath; and containing dyspnea and gradually worsened despite treatment with amoxicillin and bronchodilators.

The effect of microencapsulated phase‐change materials (MPCM) on the rheological properties of pre‐set geopolymer and Portland cement mortars was examined. Microcapsules with hydrophilic and hydrophobic shells were compared. The shear rate dependency of the viscosities fitted well to a double Carreau model. The zero shear viscosities are higher for geopolymer mortar, illustrating poorer workability. The time evolution of the viscosities was explored at shear rates of 1 and 10 s−1. New empirical equations were developed to quantify the time‐dependent viscosity changes. The highest shear rate disrupted the buildup of the mortar structures much more than the lower shear rate. Microcapsules with a hydrophobic shell affect the rheological properties much less than the microcapsules with a hydrophilic shell, due to the higher water adsorption onto the hydrophilic microcapsules. Shear forces was found to break down the initial structures within geopolymer mortars more easily than for Portland cement mortars, while the geopolymer reaction products are able to withstand shear forces better than Portland cement hydration products. Initially, the viscosity of geopolymer mortars increases relatively slowly during due to formation of geopolymer precursors; at longer times, there is a steeper viscosity rise caused by the development of a 3D‐geopolymer network. Disruption of agglomerates causes the viscosities of portland cement mortars to decrease during the first few minutes, after which the hydration process (increasing viscosities) competes with shear‐induced disruption of the structures (decreasing viscosities), resulting in a complex viscosity behavior. [ABSTRACT FROM AUTHOR]

ABSTRACT The microencapsulation of linoleic (LinA), oleic, erucic, and palmitic acids (PAs) from styrene and divinylbenzene were studied by using the suspension-like polymerization technique. All materials exhibited a spherical shape, with a particle size between 166 and 416 μm. The phase change material (PCM) content decreased with the presence of double bonds in the fatty acid molecule. The thermal energy storage (TES) capacity of the microcapsules (MC) containing saturated PA was the highest (123.30 J g−1). Whereas, the lowest TES capacity was observed for the LinA. TES capacity values from unsaturated fatty acid materials and the high particle yield indicated that these kinds of acids played two different roles, as PCM and also as monomers, in the radical polymerization processes. At high initiator concentrations, the unsaturated fatty acids were observed to react. This was confirmed by Fourier transform infrared where the peak assigned to the CC bond disappears in the spectrum of MC. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45970. [ABSTRACT FROM AUTHOR]

Microorganisms able to degrade aromatic contaminants constitute potential valuable biocatalysts to deal with a significant reusable carbon fraction suitable for eco-efficient valorization processes. Metabolic engineering of anaerobic pathways for degradation and recycling of aromatic compounds is an almost unexplored field. In this work, we present the construction of a functional bzd cassette encoding the benzoyl-CoA central pathway for the anaerobic degradation of benzoate. The bzd cassette has been used to expand the ability of some denitrifying bacteria to use benzoate as sole carbon source under anaerobic conditions, and it paves the way for future pathway engineering of efficient anaerobic biodegraders of aromatic compounds whose degradation generates benzoyl-CoA as central intermediate. Moreover, a recombinant Azoarcus sp. CIB strain harbouring the bzd cassette was shown to behave as a valuable biocatalyst for anaerobic toluene valorization towards the synthesis of poly-3-hydroxybutyrate ( PHB), a biodegradable and biocompatible polyester of increasing biotechnological interest as a sustainable alternative to classical oil-derived polymers. [ABSTRACT FROM AUTHOR]

Saffron spice has been successfully used as an ingredient in dairy products as a means of diversification. The objective of this work was to determine the influence of saffron on the volatiles' profile of a pressed ewes' milk cheese. This was performed by means of a modern extraction technique based on headspace sorptive extraction. Results showed that safranal was the only volatile that could be identified and quantified from saffron spice. Most volatile compounds were present in all cheeses but at different concentrations. Differences between control and saffron cheeses were observed, but as ripening time increased, these differences were less evident. [ABSTRACT FROM AUTHOR]

BACKGROUND The use of aromatic plant extracts as ingredients may be compromised owing to low transference and activity lack in food matrixes compared with in vitro trials. Rosemary essential oil ( REO) was added to sheep milk to study the transference of its compounds during the cheese-making process and to determine how cheese antimicrobial activity is modified. RESULTS The volatile characterization of dairy samples was performed using headspace stir bar sorptive extraction coupled to gas chromatography/mass spectrometry ( HS-SBSE/ GC/ MS) so that fat matrix interferences were reduced. This method detected a decrease in volatile recovery concentration of 19.33% when REO was added to milk. A total recovery volatile yield of 62.51% was measured from the initial quantification of milk to cheese, with hydrocarbon volatiles being transferred in a higher ratio (64.88%) than oxygenated ones (58.74%). No effects were observed for REO in fortified cheese on the counts of native flora necessary for ripening processes, but the total inhibition of Clostridium spp. was provoked CONCLUSION The study of active compound transference during cheese elaboration was achieved. The antimicrobial results in fortified cheeses with REO showed a preventive effect in the case of clostridial species, which are responsible for late cheese blowing. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND The adsorption and desorption of phenol, 2-chlorophenol (2-CPh), 4-chlorophenol (4-CPh) and 2,4-dichlorophenol (2,4-DCPh) were carried out using granular activated carbon (GAC) as adsorbent and supercritical CO2 as regenerant. Adsorption studies at three different temperatures were fitted by using two thermodynamic adsorption models, Langmuir and Toth. The GAC regeneration by CO2 at four different pressures and two temperatures was studied and the design basic parameters were found. RESULTS The Toth model fitted the experimental data better and thermodynamic properties indicated that this adsorption process was spontaneous, feasible and exothermic. Values of standard enthalpy lower than 40 kJ mol-1 confirmed that adsorption processes were carried out by physical adsorption. It was also observed that the higher the pressure the higher the regeneration efficiency due to the increase in solvent density. CONCLUSION GAC presented high selectivity for these substituted phenols and the order of adsorption was 2,4-DCPh > 4-CPh > 2CPh > phenol. Supercritical technology was able to regenerate the exhausted GAC, achieving yields comparable with those exhibited by traditional technologies but avoiding additional separation processes. The effective diffusivities of phenols followed the order phenol > 2-CPh≅4-CPh > 2,4-DCPh. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Rigid polyurethane (RPU) foams were synthesized incorporating up to 18 wt % of two different kinds of thermo-regulating microcapsules having a different shell material consisting of polystyrene or poly(methyl methacrylate), named as mSP-(PS-RT27) and Micronal®DS 5001X, respectively. The type of microcapsules and their content affected the final foam height, which decreased with the content and particle size. However, the foam rising curve shape was not dependent on the microcapsules type or content and was successfully predicted by means of a model of reaction curve of four tanks in series. Thermal energy storage (TES) capacity of PU foams was improved by incorporating both, mSP-(PS-RT27) or Micronal®DS 5001X, with the values close to those reported in the literature (16 J/g) for the highest content. Nevertheless, the highest particle size of the microcapsules from PS and the agglomeration of the microcapsules from poly(methyl methacrylate), promoted by their additive SiO2, led to the strut rupture, damaging the final mechanical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

BACKGROUND: The use of aromatic plants and their extracts with antimicrobial properties may be compromised in the case of cheese, as some type of fungal starter is needed during its production. Penicillium verrucosum is considered a common cheese spoiler. The aim of this study was to evaluate the innovative use of certain aromatic plants as natural cheese covers in order to prevent mycotoxicogenic fungal growth ( P. verrucosum). A collection of 12 essential oils (EOs) was obtained from various aromatic plants by solvent-free microwave extraction technology, and volatile characterisation of the EOs was carried out by gas chromatography/mass spectrometry. RESULTS: The most effective EOs against P. verrucosum were obtained from Anethum graveolens, Hyssopus officinalis and Chamaemelum nobile, yielding 50% inhibition of fungal growth at concentration values lower than 0.02 µL mL−1. All EOs showed high volatile heterogeneity, with α-phellandrene, pinocamphone, isopinocamphone, α-pinene, camphene, 1,8-cineole, carvacrol and trans-anethole being found to be statistically significant in the antifungal model. CONCLUSION: The use of these aromatic plants as natural covers on cheese can satisfactorily inhibit the growth of some mycotoxicogenic fungal spoilers. Among the volatile compounds present, α- and β-phellandrene were confirmed as the most relevant in the inhibition. © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The mbd cluster encoding genes of the 3-methylbenzoyl-CoA pathway involved in the anaerobic catabolism of 3-methylbenzoate and m-xylene was characterized for the first time in the denitrifying β- Proteobacterium Azoarcus sp. CIB. The mbdA gene product was identified as a 3-methylbenzoate-CoA ligase required for 3-methylbenzoate activation; its substrate spectrum was unique in activating all three methylbenzoate isomers. An inducible 3-methylbenzoyl-CoA reductase ( mbdONQP gene products), displaying significant amino acid sequence similarities to known class I benzoyl-CoA reductases catalysed the ATP-dependent reduction of 3-methylbenzoyl-CoA to a methyldienoyl-CoA. The mbdW gene encodes a methyldienoyl-CoA hydratase that hydrated the methyldienoyl-CoA to a methyl-6-hydroxymonoenoyl-CoA compound. The mbd cluster also contains the genes predicted to be involved in the subsequent steps of the 3-methylbenzoyl-CoA pathway as well as the electron donor system for the reductase activity. Whereas the catabolic mbd genes are organized in two divergent inducible operons, the putative mbdR regulatory gene was transcribed separately and showed constitutive expression. The efficient expression of the mbd genes required the oxygen-dependent AcpR activator, and it was subject of carbon catabolite repression by some organic acids and amino acids. Sequence analyses suggest that the mbd gene cluster was recruited by Azoarcus sp. CIB through horizontal gene transfer. [ABSTRACT FROM AUTHOR]

In this work, the gcdH gene from the denitrifying β-proteobacterium Azoarcus sp. CIB was shown to encode a glutaryl-CoA dehydrogenase, which is essential for the anaerobic catabolism of many aromatic compounds and some alicyclic and dicarboxylic acids. The primary structure of the GcdH protein is highly conserved in many organisms. The divergently transcribed gcdR gene, encoding a LysR-type transcriptional regulator, accounts for the glutaconate/glutarate-specific activation of the Pg promoter driving expression of gcdH. The Azoarcus sp. CIBd gcdH mutant strain harbouring a disrupted gcdH gene was used as host to identify heterologous gcdH genes, such as that from Pseudomonas putida KT2440. Moreover, the expression of gcdH from P. putida can be efficiently controlled by the GcdR activator in Azoarcus sp. CIB, demonstrating the existence of cross-talk between GcdR regulators and gcdH promoters from members of different phylogenetic subgroups of proteobacteria. [ABSTRACT FROM AUTHOR]

The authors present a reply to comments on their article on the consideration of genetic disorders before diagnosis of Interstitial Pneumonia with Autoimmune Features (IPAF). Topics discussed include the required exclusion of patients with alternative etiologies in IPAF classification criteria (2), and the non-mention of disorders that can present with ILD and multisystem immune dysregulation. Also noted is likely further diagnoses of patients with these disorders.

The effect of FtsH, an essential inner membrane-bound protease, in the regulation of the σ54-dependent Pu promoter has been examined in vivo. Escherichia coli cells lacking FtsH failed to activate a Pu–lacZ fusion in response to the cognate enhancer-binding protein XylR. However, the intracellular concentrations of XylR and σ54, as well as their apparent physical integrity were the same regardless of the presence or absence of the protease. The loss of Pu activity in FtsH-minus cells was not due to the imbalance between sigma factors caused by the lack of the protease. ftsH mutants could not grow in media with glutamine as the only nitrogen source and failed also to induce the σ54 promoters PnifH by NifA and PpspA by PspF. These lesions were fully complemented by a ftsH + plasmid. Therefore, part of the pleiotropic phenotype of FtsH-less cells corresponded to the lack of σ54 activity. Overproduction of σ54, however, restored both transcriptional activity of Pu and growth in glutamine of a ftsH strain. These observations suggested that the activity of σ54 is checked in vivo by an interplay of factors that ultimately determine the performance of cognate promoters under given physiological conditions. [ABSTRACT FROM AUTHOR]

The article offers information on the 19th Annual Conference of the International Society for Bipolar Disorders (ISBD) of the Scientific Program and Steering Committees to be held in Washington D.C. in May 2017.

An obituary for American psychiatrist Vivek Singh is presented.