Hydrophobic interpenetrating polyamide-PDMS membranes for desalination, pesticides removal and enhanced chlorine tolerance.

Hydrophobic membranes for desalination and toxic organic pollutant removal have been fabricated using polyamide - PDMS (polydimethylsiloxane) chemistries in a one-step protocol. The curing of polyamide and PDMS are orthogonal and co-curing both networks imparts hydrophobicity to the thin film composite membranes. The membranes exhibit increased adsorption of pesticides from the feed water along with maintaining excellent salt rejection capability (97% NaCl rejection), thus giving the membranes a multifunctional character. Three toxic pesticides have been used in this study to demonstrate the viability of combining osmosis desalination technology with organic matter adsorption. The membranes also show excellent resistance to fouling by toxic pesticides (85% salt rejection vs 67% for commercial membranes in the presence of pesticides) and significantly improved chlorine tolerance (93.8% salt rejection vs 86.5% for commercial membranes after 20 h of exposure to sodium hypochlorite solution).

Effect of peroxomonosulfate, peroxodisulfate and hydrogen peroxide on graphene oxide photocatalytic performances in methyl orange dye degradation.

Carbocatalyst GO photocatalytic mechanism and performances in the presence of an electron scavenger (ES) has been consciously discussed herein. Single layer GO photocatalyst has been synthesized by Hummer's method and photocatalyst characteristics are gathered by different analytical methods. Studies ensured the formation of a good crystalline GO that contains number of oxygenated functional groups, with average crystalline size of the sp2 domain in 18.24 nm. Optical studies suggest that optical band gap of the GO nanosheet photocatalyst is found in the range of 3.19-4.4 eV. TEM analysis confirms the formation of a single layer GO nanosheet. Photocatalytic study justifies that in the absence of ES, 24% mineralization efficiency is achieved with GO as a photocatalyst, whereas in the presence of ES such as PMS, PDS and HP the mineralization efficiency is considerably enhanced up to 91%, 77% and 65% respectively. Moreover, photocatalytic degradation intermediate byproducts were also examined through LC-MS analysis. The study substantiates methyl orange dye degradation undergoes via the multiple degradation pathway such as (i) azo bond cleavage and hydroxylation, (ii), asymmetric cleavage followed by reduction of sulfonate group and aromatic ring removal and (iii) consecutive demethylation reactions and sulfonate group removal. Rationalized the contributing effects of process parameters towards the photocatalytic degradation of methyl orange using a RSM based on CCD validation. The validation reveals that most significant process parameter affects degradation process are the irradiation time, catalyst loading and choice of ES.

Safety and bioactivity studies of Jasad Bhasma and its in-process intermediate in Swiss mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Bhasma, Ayurvedic medicinal preparations, are prepared using herbs and minerals on following long iterative procedures. However, industrially mercury and sulphur are more commonly used to prepare bhasma from its raw material. The end point of this iterative procedure is mainly judged by the traditional tests specifying physical appearance of the powders. They fail to give better idea about chemical nature of the material. Moreover, the differences in biological activity of final product verses intermediate are not addressed. AIM OF THE STUDY: To compare the physicochemical as well as biological properties of the Jasad bhasma and its in-process intermediate using modern science methods. MATERIALS AND METHODS: The Jasad bhasma and its in-process intermediate are characterized for their physicochemical properties using electron microscopy, x-ray diffraction and CHNS(O) analysis. The biological effects of both the preparations are then studied. The bioaccumulation of zinc, effect on liver antioxidant status, liver and kidney function (by conventional tests as well as SPECT: Single Photon Emission Computed Tomography), effect on blood cells and effect on immune system are studied in mice model, Swiss albino. Since bhasma is given with an accompaniment (anupan), all the bioactivity studies were carried out by administering the preparation with and without Amala powder (Phyllanthus emblica L., fruit, dry powder) as anupan. RESULTS: The XRD results accompanied with Rietveld analysis indicate that the final bhasma is mainly oxide of zinc, whereas the intermediate is mainly sulphide of zinc. The animal studies show that the bhasma as well as its intermediate do not lead to any bioaccumulation of zinc in major organs, when administered with and without anupan. Both, bhasma and intermediate do not cause any deleterious effects on kidney and liver as indicated by blood biochemistry and SPECT studies. However, the intermediate perturbs antioxidant status more and affects the platelet turnover, in comparison with bhasma. On 28day treatment, the bhasma treated animals show prominence of TH1 mediated immune response whereas, intermediate treated animals show prominence of TH2 mediated immune response. CONCLUSION: A set of simple modern microscopy and diffraction techniques can affirmatively identify in-process intermediate from the final preparation. These can be used to decide the end point of long and iterative preparation methods in accordance with modern science practices. The differences in physicochemical properties of particles from the two preparations reflect in their different biological effects. Moreover, the bhasma affects several components of biological systems which again in-turn interact with each other, which emphasizes the need of multifaceted studies in this field.

(R)-PAC biosynthesis in [BMIM][PF6]/aqueous biphasic system using Saccharomyces cerevisiae BY4741 cells.

(R)-phenylacetylcarbinol or (R)-PAC is a pharmaceutical precursor of (1R, 2S) ephedrine and (1S, 2S) pseudoephedrine. Biotransformation of benzaldehyde and glucose by pyruvate decarboxylase produces (R)-PAC. This biotransformation suffers from toxicity of the substrate, product [(R)-PAC] and by-product (benzyl alcohol). In the present study, ionic liquid/aqueous biphasic system was employed to enhance (R)-PAC production. Fermented broth was the reaction medium in which Saccharomyces cerevisiae BY4741 was the source of pyruvate decarboxylase. Hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) was the non-aqueous phase in which toxic compounds reside. Biocompatibility of [BMIM][PF6] and adequate distribution coefficients of benzaldehyde, (R)-PAC and benzyl alcohol were determined. A Box-Behnken design and response surface methodology were used for the optimization of biotransformation variables in order to maximize (R)-PAC yield and productivity. The results showed higher (R)-PAC yield and productivity of ∼1.5-fold each in the biphasic biotransformation of phase volume ratio 0.05 as compared to the monophasic (conventional) biotransformation. Moreover, the level of major by-product benzyl alcohol was also 3.5-fold lower in biphasic biotransformation. [BMIM][PF6]/aqueous biphasic system is a new approach which could intensify the (R)-PAC production.

Cell (A549)-particle (Jasada Bhasma) interactions using Raman spectroscopy.

Current methods for the evaluation of cell interactions with particles are nonspecific, slow, and invasive to the cells. Raman spectroscopy is a noninvasive technique, and is used in the present study to investigate particle-cell interactions. The main focus of the present study is to employ Raman spectroscopy for investigating the interaction of human lung adenocarcinoma cell line (A549) with the particulate system Jasada Bhasma, a traditional Indian medicine. Jasada Bhasma is a unique preparation of zinc and is traditionally used for the treatment of various diseases like diabetes, age-related eye diseases, and as a health promotional tonic. The Raman spectral analysis is executed by identifying the difference in intracellular DNA/RNA, and proteins and lipids concentration between particles--treated and untreated cells. Comparison between Bhasma-treated and -untreated cells indicates that vibrational peaks corresponding to the DNA/RNA molecule show a significant increase in cells treated with the Jasada Bhasma. Apart from the DNA molecule, several other vibrational peaks related to the protein molecules also show a significant increase in A549 cells after treatment with Bhasma. These results indicate that Bhasma treatment of A549 possibly delays DNA degradation and enables retention of higher amount of protein molecules in the cells.

Intracellular reactive oxygen species mediate suppression of sporulation in Bacillus subtilis under shear stress.

Sporulation is an important cellular response to stress that is also significant from a bioreactor operation viewpoint. While sporulating organisms are known to show an enhanced sporulation response under several stress situations, the sporulation response to shear stress has not been investigated thus far. Such a study could be of interest since shear stress, to a greater or lesser degree, is always present in bioreactor operation. In this article, we investigate the sporulation extents of the Gram-positive bacteria Bacillus subtilis at various defined shear levels. We show that, contrary to expectations, shear inhibits sporulation. We found an inverse correlation between the shear rate-dependent specific intracellular reactive oxygen species level (siROS), and the sporulation extent. A 10-fold increase in siROS resulted in about 17-fold decrease in sporulation extent. The involvement of reactive oxygen species (ROS) in sporulation was unknown thus far. Further, through experiments that specifically increased and reduced intracellular ROS (iROS), we established that siROS is responsible for the inhibition of sporulation under shear stress. In addition, we found that shear induced siROS regulated the expression levels of the general stress proteins Ctc and sigma(B). Based on the above, we hypothesize that siROS may regulate suppression of sporulation under high shear by altering sigma(B) and Ctc expression levels, and a model for the same is presented.

Effect of preculturing conditions on growth of Lactobacillus rhamnosus on medium containing glucose and citrate.

Lactobacillus rhamnosus can metabolize citrate through a citrate inducible transport system. The growth curves of L. rhamnosus on medium containing glucose and citrate was found to be highly dependent on preculturing conditions. It exhibited diauxic growth when precultured on glucose, but demonstrated simultaneous consumption when cultured on citrate. The maximum specific growth rate for cells growing on glucose + citrate was 0.38 h-1, which was higher than the growth rate on individual substrates (0.28 h-1). Simultaneous consumption also yielded higher net flavour compounds, diacetyl and acetoin. Flux analysis indicated that L. rhamnosus requires oxygen for balancing excess NADH through NADH oxidase. The flux analysis provided insights into the metabolic network of L. rhamnosus.

Macro-level and genetic-level responses of Bacillus subtilis to shear stress.

Responses of bacterial (Bacillus subtilis) cells under different shear levels, from both the macro and genetic viewpoints, have been presented. The responses were studied using a novel, couette flow bioreactor (CFB), in which the entire cultivation can be performed under defined shear conditions. Oxygen supply, the normal limiting factor for entire cultivations under defined shear conditions, has been achieved by passing air through a poly(tetrafluoroethylene) (PTFE) membrane fixed on the inner cylinder of the CFB. More importantly, analyses of the oxygen transfer capabilities as well as the shear rates show that in this CFB, the effects of defined shear can be studied without interference from the effects of oxygen supply. Further, the shake flask can be used as a proper control for studying the shear effects, mainly because the shear rate in the shake flask under normal shaker operating conditions of 190 rpm has been estimated to be a negligible 0.028 s(-1) compared to a value of 445 s(-1) at the lowest rpm employed in the CFB. At the macro level the cell size decreased by almost 50% at 1482 s(-1) compared to that at 0.028 s(-1), the growth rate increased by 245%, and the maximum cell concentration increased by 190% when the shear rate was increased from 0.028 to 1482 s(-1). The specific intracellular catalase level increased by 335% and protease by 87% at 1482 s(-1) as compared to the control cultures at a shear rate 0.028 s(-1). In addition, the specific intracellular reactive oxygen species level (siROS) at the highest shear rate was 9.3-fold compared to the control conditions. At the genetic level we have established the involvement of the transcription factor, sigma(B), in the bacterial responses to shear stress, which was unknown in the literature thus far; the sigma(B) expression correlated inversely with the siROS. Further, through experiments with ROS quenchers, we showed that ROS regulated sigma(B) expression under shear.