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1.
Ecotoxicol Environ Saf ; 208: 111621, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396141

RESUMO

The study explored the polycyclic aromatic hydrocarbon tolerance of indigenous biosurfactant producing microorganisms. Three bacterial species were isolated from crude oil contaminated sites of Haldia, West Bengal. The three species were screened for biosurfactant production and identified by 16S rRNA sequencing as Brevundimonas sp. IITISM 11, Pseudomonas sp. IITISM 19 and Pseudomonas sp. IITISM 24. The strains showed emulsification activities of 51%, 57% and 63%, respectively. The purified biosurfactants were characterised using FT-IR, GC-MS and NMR spectroscopy and found to have structural similarities to glycolipopeptides, cyclic lipopeptides and glycolipids. The biosurfactants produced were found to be stable under a wide range of temperature (0-100 °C), pH (4-12) and salinity (up to 20% NaCl). Moreover, the strains displayed tolerance to high concentrations (275 mg/L) of anthracene and fluorene and showed a good amount of cell surface hydrophobicity with different hydrocarbons. The study reports the production and characterisation of biosurfactant by Brevundimonas sp. for the first time. Additionally, the kinetic parameters of the bacterial strains grown on up to 300 mg/L concentration of anthracene and fluorene, ranged between 0.0131 and 0.0156 µmax (h-1), while the Ks(mg/L) ranged between 59.28 and 102.66 for Monod's Model. For Haldane-Andrew's model, µmax (h-1) varied between 0.0168 and 0.0198. The inhibition constant was highest for Pseudomonas sp. IITISM 19 on anthracene and Brevundimonas sp. IITISM 11 on fluorene. The findings of the study suggest that indigenous biosurfactant producing strains have tolerance to high PAH concentrations and can be exploited for bioremediation purposes.


Assuntos
Antracenos/metabolismo , Biodegradação Ambiental , Fluorenos/metabolismo , Tensoativos/metabolismo , Antracenos/química , Bactérias/metabolismo , Fluorenos/química , Glicolipídeos , Hidrocarbonetos/metabolismo , Cinética , Petróleo/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Pseudomonas/metabolismo , RNA Ribossômico 16S/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Tensoativos/química
2.
J Vis Exp ; (160)2020 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-32568221

RESUMO

Single molecule localization microscopy (SMLM) techniques overcome the optical diffraction limit of conventional fluorescence microscopy and can resolve intracellular structures and the dynamics of biomolecules with ~20 nm precision. A prerequisite for SMLM are fluorophores that transition from a dark to a fluorescent state in order to avoid spatio-temporal overlap of their point spread functions in each of the thousands of data acquisition frames. BODIPYs are well-established dyes with numerous conjugates used in conventional microscopy. The transient formation of red-shifted BODIPY ground-state dimers (DII) results in bright single molecule emission enabling single molecule localization microscopy (SMLM). Here we present a simple but versatile protocol for SMLM with conventional BODIPY conjugates in living yeast and mammalian cells. This procedure can be used to acquire super-resolution images and to track single BODIPY-DII states to extract spatio-temporal information of BODIPY conjugates. We apply this procedure to resolve lipid droplets (LDs), fatty acids, and lysosomes in living yeast and mammalian cells at the nanoscopic length scale. Furthermore, we demonstrate the multi-color imaging capability with BODIPY dyes when used in conjunction with other fluorescent probes. Our representative results show the differential spatial distribution and mobility of BODIPY-fatty acids and neutral lipids in yeast under fed and fasted conditions. This optimized protocol for SMLM can be used with hundreds of commercially available BODIPY conjugates and is a useful resource to study biological processes at the nanoscale far beyond the applications of this work.


Assuntos
Compostos de Boro/química , Corantes Fluorescentes/química , Microscopia de Fluorescência/métodos , Imagem Individual de Molécula/métodos , Animais , Compostos de Boro/metabolismo , Sobrevivência Celular , Cor , Ácidos Graxos/metabolismo , Corantes Fluorescentes/metabolismo , Gotículas Lipídicas/metabolismo , Lisossomos/metabolismo , Leveduras/citologia
3.
Nat Commun ; 10(1): 3400, 2019 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-31363088

RESUMO

Single-molecule localization microscopy (SMLM) is a rapidly evolving technique to resolve subcellular structures and single-molecule dynamics at the nanoscale. Here, we employ conventional BODIPY conjugates for live-cell SMLM via their previously reported red-shifted ground-state dimers (DII), which transiently form through bi-molecular encounters and emit bright single-molecule fluorescence. We employ the versatility of DII-state SMLM to resolve the nanoscopic spatial regulation and dynamics of single fatty acid analogs (FAas) and lipid droplets (LDs) in living yeast and mammalian cells with two colors. In fed cells, FAas localize to the endoplasmic reticulum and LDs of ~125 nm diameter. Upon fasting, however, FAas form dense, non-LD clusters of ~100 nm diameter at the plasma membrane and transition from free diffusion to confined immobilization. Our reported SMLM capability of conventional BODIPY conjugates is further demonstrated by imaging lysosomes in mammalian cells and enables simple and versatile live-cell imaging of sub-cellular structures at the nanoscale.


Assuntos
Compostos de Boro/química , Rastreamento de Células/métodos , Corantes Fluorescentes/química , Imagem Individual de Molécula/métodos , Linhagem Celular Tumoral , Rastreamento de Células/instrumentação , Células/química , Células/citologia , Células/metabolismo , Retículo Endoplasmático/química , Retículo Endoplasmático/metabolismo , Humanos , Gotículas Lipídicas/química , Gotículas Lipídicas/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/metabolismo , Imagem Individual de Molécula/instrumentação
4.
Food Chem ; 301: 125298, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31387044

RESUMO

A synthetic scenario for functionalization of ß-lactoglobulin (ßLg) with polymeric units containing caffeic acid (ßLg-polyCA) was developed; and all intermediates and final products were structurally confirmed using nuclear magnetic resonance spectroscopy, matrix assisted laser desorption ionization time-of-flight mass spectrometry, and physico-chemically characterized using differential scanning calorimetry and circular dichroism. The antioxidant properties and emulsion stability of ßLg, ßLg-CA conjugate and ßLg-polyCA based systems containing high percentage of fish oil (50%) were evaluated; and ßLg-polyCA presented the highest antioxidant and free radical-scavenging activity based on DPPH, ABTS and HS scavenging assays (92.4, 87.92 and 67.35% respectively). Thiobarbituric acid (TBARS) test demonstrated that compared to native ßLg, ßLg-polyCA afford up 4-5 fold of inhibition of oxidative rancidity and displayed drastic secondary structure changes. Compared to native ßLg based emulsions, ßLg-polyCA had larger oil droplet sizes, stronger negative zeta potentials (-69.9 mv), narrower size distributions (PDI: 0.22) and less creaming index.


Assuntos
Antioxidantes/farmacologia , Emulsões/química , Óleos de Peixe/química , Lactoglobulinas/química , Fenóis/química , Antioxidantes/química , Ácidos Cafeicos/química , Varredura Diferencial de Calorimetria , Dicroísmo Circular , Difusão Dinâmica da Luz , Peroxidação de Lipídeos , Espectroscopia de Ressonância Magnética , Oxirredução , Polimerização , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
5.
Bioresour Technol ; 271: 383-390, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30296745

RESUMO

This work intends towards the preparation of different grades of cationic locust bean gum biopolymer (CLBG) through the incorporation of 2,3-epoxypropyltrimethylammonium chloride (GTMAC) on to the pristine locust bean gum (LBG) biopolymer. Among them the best grade was further selected, characterized and their flocculation efficacy was evaluated towards harvesting of three different indigenous isolated green microalgae viz. Chlorella sp. NCQ, Micractinium sp. NCS2 and Scenedesmus sp. CBIIT(ISM). Flocculation efficiency of 96.68%, 96.64%, and 97.42% were obtained for Chlorella sp. NCQ, Micractinium sp. NCS2 and Scenedesmus sp. CBIIT(ISM) at an optimum dosage of 55, 40, and 30 ppm respectively. Thus CLBG was proven to be an efficient flocculant towards harvesting of green microalgae than its natural form.


Assuntos
Biopolímeros/metabolismo , Galactanos/metabolismo , Mananas/metabolismo , Microalgas , Gomas Vegetais/metabolismo , Biopolímeros/química , Cátions , Chlorella , Floculação
6.
Biotechnol Biofuels ; 11: 185, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29988523

RESUMO

In the wake of the uprising global energy crisis, microalgae have emerged as an alternate feedstock for biofuel production. In addition, microalgae bear immense potential as bio-cell factories in terms of producing key chemicals, recombinant proteins, enzymes, lipid, hydrogen and alcohol. Abstraction of such high-value products (algal biorefinery approach) facilitates to make microalgae-based renewable energy an economically viable option. Synthetic biology is an emerging field that harmoniously blends science and engineering to help design and construct novel biological systems, with an aim to achieve rationally formulated objectives. However, resources and tools used for such nuclear manipulation, construction of synthetic gene network and genome-scale reconstruction of microalgae are limited. Herein, we present recent developments in the upcoming field of microalgae employed as a model system for synthetic biology applications and highlight the importance of genome-scale reconstruction models and kinetic models, to maximize the metabolic output by understanding the intricacies of algal growth. This review also examines the role played by microalgae as biorefineries, microalgal culture conditions and various operating parameters that need to be optimized to yield biofuel that can be economically competitive with fossil fuels.

7.
J Colloid Interface Sci ; 523: 169-178, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29621644

RESUMO

HYPOTHESIS: In multi-phase systems, many complex reactions take place at the interface where a molecule equipped with manifold functionalities is demanded. By taking advantage of the surface-active property of phosphatidylcholine (PC) scaffold and antioxidant properties of phenolic acids, new multifunctional molecules are generated, which are expected to confer physical and oxidative stability to sensitive bioactive ingredients in delivery systems. EXPERIMENTS: This work reports a successful synthesis of two new arrays of phenophospholipids sn-1-acyl(C12-C18)-sn-2-caffeoyl and sn-1-caffeoyl-sn-2-acyl phosphatidylcholines via mild scalable regiospecific pathways; as structurally verified by MS, 1H/13C NMR analyses, and characterized by critical micelle concentrations (CMC), FTIR, and DSC analysis. Synthesized phenophospholipids are subjected to stabilizing o/w emulsion, and antioxidation tests as demonstrated by TBARS (Thiobarbituric Acid Reactive Substances) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays. FINDINGS: This study has demonstrated that; (1) phenophospholipids with a broad spectrum of CMC are created, affording superior emulsion stability than soybean PC; (2) all phenophospholipids present improved oxidation inhibition and sn-2-caffeoyl phenophospholipids display superior performance to sn-1-caffeoyl phenophospholipids, soybean PC or admixture of caffeic acid and soybean PC; (3) incorporation of caffeoyl in PC scaffold does not sacrifice radical scavenging ability of caffeic acid, whilst the ion chelating capacity of sn-1-myristoyl(C14)-sn-2-caffeoyl PC enhance by 4.5 times compared to soy PC. Fluorescence Microscopy imaging verified the location of phenophospholipids in the interface as desired. Among synthetic phenophospholipids, sn-1-myristoyl(C14)-sn-2-caffeoyl PC commits the cut-off effect in most desired functionalities, which might be of great potential for multi-purpose applications.

8.
Crit Rev Biotechnol ; 38(3): 369-385, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-28793788

RESUMO

BACKGROUND: In the wake of rising energy demands, microalgae have emerged as potential sources of sustainable and renewable carbon-neutral fuels, such as bio-hydrogen and bio-oil. PURPOSE: For rational metabolic engineering, the elucidation of metabolic pathways in fine detail and their manipulation according to requirements is the key to exploiting the use of microalgae. Emergence of site-specific nucleases have revolutionized applied research leading to biotechnological gains. Genome engineering as well as modulation of the endogenous genome with high precision using CRISPR systems is being gradually employed in microalgal research. Further, to optimize and produce better algal platforms, use of systems biology network analysis and integration of omics data is required. This review discusses two important approaches: systems biology and gene editing strategies used on microalgal systems with a focus on biofuel production and sustainable solutions. It also emphasizes that the integration of such systems would contribute and compliment applied research on microalgae. CONCLUSIONS: Recent advances in microalgae are discussed, including systems biology, gene editing approaches in lipid bio-synthesis, and antenna engineering. Lastly, it has been attempted here to showcase how CRISPR/Cas systems are a better editing tool than existing techniques that can be utilized for gene modulation and engineering during biofuel production.


Assuntos
Edição de Genes/métodos , Lipídeos/biossíntese , Microalgas/metabolismo , Biologia de Sistemas/métodos , Vias Biossintéticas , Engenharia Genética
9.
Food Chem ; 241: 281-289, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28958530

RESUMO

Multi-functional phenolic emulsifiers were prepared by covalently coupling ß-Lactoglobulin (ßLg) to caffeic acid (CA) using crosslinker chemistry at different pH conditions (pH 2.5, 6.0, and 8.5). The resulting bioconjugates were characterized by MALDI-TOF MS, differential scanning calorimetry (DSC), fluorescence-quenching, infrared and circular dichroism spectroscopies. Furthermore, the emulsifying and antioxidant properties of ßLg-CA conjugates were evaluated and compared to native ß-Lactoglobulin and the non-covalent ß-lactoglobulin/caffeic complex (ßLg/CA). Results showed: 1) An optimal molar ratio (8:1) of caffeic acid to ßLg was obtained at pH 6; 2) DPPH activity of ßLg-CA increases as the number of CA units coupled increases; 3) ßLg-CA conjugates displayed comparable or superior water solubility than native ßLg and ßLg/CA. Moreover, DSC results showed that coupling of CA with ßLg significantly increased the thermal stability of ßLg. In summary, ßLg-CA conjugates can act as effective antioxidant emulsifiers and stabilizers and may find application in food and cosmetic industries.


Assuntos
Proteínas do Leite/análise , Animais , Fenômenos Químicos , Concentração de Íons de Hidrogênio , Lactoglobulinas , Leite , Fenóis
10.
J Colloid Interface Sci ; 508: 230-236, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-28841481

RESUMO

HYPOTHESIS: Anionic surfactants can form stable monolayers around oil droplets via interactions with macromolecules thereby physically stabilizing high fish oil enriched emulsions (50-70% fish oil) while phenolic acids have antioxidant properties to prevent lipid oxidation. COSMO-RS (Conductor-like Screening Model for Real Solvents) is a powerful tool for the rational design of molecules with multi-functionalities. Therefore, it should be possible to assemble segments of natural molecules into a single multifunctional molecule using COSMO-RS to confer both physical and oxidative stability to fish oil enriched systems. EXPERIMENTS: COSMO-RS was used to predict the thermodynamic properties of series phenoleoyl malic acid esters of monoglycerides in comparison with commercial emulsifiers. A novel series of amphiphilic lipids, equipped with multi-functional groups from natural building blocks (fatty-acyl, glycerol, malic & phenolic acids), were then synthesized in a facile approach and characterized by various spectroscopy techniques. Oil-in-water emulsions stabilized by the amphiphilic lipids were formulated and characterized by dynamic light scattering measurements and fluorescence imaging. FINDINGS: An elaborate integration of multi-functions into a single molecule was achieved, displaying superior or comparable emulsion stability and antioxidant property, compared to a commercial emulsifier, phenolic acids and their combinations. This is the first report to holistically integrate the rational design, synthesis and functional characterization of natural-based multifunctional molecules for high capacity fish oil delivery systems.

11.
3 Biotech ; 7(3): 197, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28667637

RESUMO

Biofuels are the promising sources which are produced by various microalgae or in the form of metabolic by-products from organic or food waste products. Microalgae have been widely reported for the production of biofuels since these have a high storage of lipids as triacylglycerides, which can mainly be converted into biofuels. Recently, products such as biodiesel, bioethanol and biogas have renewed the interest toward the microalgae. The proteomics alone will not pave the way toward finding an ideal alga which will fulfill the current energy demands, but a combined approach of proteomics, genomics and bioinformatics can be pivotal for a sustainable solution. The present review emphasizes various technologies currently involved in algal proteomics for the efficient production of biofuels.

12.
J Phys Chem B ; 121(32): 7550-7560, 2017 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-28723155

RESUMO

One of the key necessary steps to prevent human neurological disorders is the efficient disruption of protein aggregation or amyloid fibril. In this article, we have explored the effect of three amphiphilic surface active ionic liquids (SAILs), namely 1-methyl-3-octylimidazolium chloride ([C8mim]Cl), 1-dodecyl-3-methyllimidazolium chloride ([C12mim]Cl), and 1-hexadecyl-3-methyllimidazolium chloride ([C16mim]Cl) having concentrations of 5.8, 0.29, and 0.08 mM, respectively, on bovine serum albumin (BSA) and human serum albumin (HSA) fibril. These SAILs have different alkyl chain length attached to the cationic imidazolium headgroups. Interestingly, it is observed that all of the three SAILs exhibit fibril inhibition at room temperature itself as initially evidenced from thioflavin T (ThT) fluorescence assay study. However, C16mimCl is found as the most efficient quencher having highest quenching constant than the other two analogues. In addition, circular dichroism (CD) data give valuable insights into the conformational changes of BSA fibril as a consequence of interaction with SAILs. The field emission scanning electron microscopy (FESEM) and fluorescence lifetime imaging microscopy (FLIM) confirm the inhibitory effect of SAILs. It is evident from fluorescence correlation spectroscopy (FCS) study that 62% fibril is ruptured in the presence of C8mimCl while C12mimCl and C16mimCl completely destroy the fibrillar morphology. So the inhibition efficiency is related to the hydrophobicity associated with the long alkyl chain attached with the cationic imidazolium headgroup of SAILs.


Assuntos
Líquidos Iônicos/química , Albumina Sérica/química , Tensoativos/química , Dicroísmo Circular , Humanos , Concentração de Íons de Hidrogênio , Imidazóis/química , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Albumina Sérica/metabolismo , Espectrometria de Fluorescência
13.
Anal Chem ; 89(11): 6239-6247, 2017 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-28492305

RESUMO

The oxidation of lipids is an important phenomenon with ramifications for disciplines that range from food science to cell biology. The development and characterization of tools and techniques to monitor lipid oxidation are thus relevant. Of particular significance in this regard are tools that facilitate the study of oxidations at interfaces in heterogeneous samples (e.g., oil-in-water emulsions, cell membranes). In this article, we establish a proof-of-principle for methods to initiate and then monitor such oxidations with high spatial resolution. The experiments were performed using oil-in-water emulsions of polyunsaturated fatty acids (PUFAs) prepared from cod liver oil. We produced singlet oxygen at a point near the oil-water interface of a given PUFA droplet in a spatially localized two-photon photosensitized process. We then followed the oxidation reactions initiated by this process with the fluorescence-based imaging technique of structured illumination microscopy (SIM). We conclude that the approach reported herein has attributes well-suited to the study of lipid oxidation in heterogeneous samples.


Assuntos
Ácidos Graxos Insaturados/química , Óleos/química , Imagem Óptica , Emulsões/química , Peroxidação de Lipídeos , Tamanho da Partícula , Propriedades de Superfície , Água/química
14.
Bioresour Technol ; 242: 206-217, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28416126

RESUMO

Algal model based multi-objective optimization using elitist non-dominated sorting genetic algorithm with inheritance was carried out for batch cultivation of Dunaliella tertiolecta using NPK-fertilizer. Optimization problems involving two- and three-objective functions were solved simultaneously. The objective functions are: maximization of algae-biomass and lipid productivity with minimization of cultivation time and cost. Time variant light intensity and temperature including NPK-fertilizer, NaCl and NaHCO3 loadings are the important decision variables. Algal model involving Monod/Andrews adsorption kinetics and Droop model with internal nutrient cell quota was used for optimization studies. Sets of non-dominated (equally good) Pareto optimal solutions were obtained for the problems studied. It was observed that time variant optimal light intensity and temperature trajectories, including optimum NPK fertilizer, NaCl and NaHCO3 concentration has significant influence to improve biomass and lipid productivity under minimum cultivation time and cost. Proposed optimization studies may be helpful to implement the control strategy in scale-up operation.


Assuntos
Algoritmos , Clorófitas , Biomassa , Reatores Biológicos , Cinética , Lipídeos
15.
Biotechnol Lett ; 39(1): 1-11, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27654821

RESUMO

Microalgae are currently being considered as a clean, sustainable and renewable energy source. Enzymes that catalyse the metabolic pathways for biofuel production are specific and require strict regulation and co-ordination. Thorough knowledge of these key enzymes along with their regulatory molecules is essential to enable rational metabolic engineering, to drive the metabolic flux towards the desired metabolites of importance. This paper reviews two key enzymes that play their role in production of bio-oil: DGAT (acyl-CoA:diacylglycerol acyltransferase) and PDAT (phospholipid:diacylglycerol acyltransferase). It also deals with the transcription factors that control the enzymes while cell undergoes a metabolic shift under stress. The paper also discusses the association of other enzymes and pathways that provide substrates and precursors for oil accumulation. Finally a futuristic solution has been proposed about a synthetic algal cell platform that would be committed towards biofuel synthesis.


Assuntos
Chlamydomonas/metabolismo , Microalgas/metabolismo , Nitrogênio/metabolismo , Diacilglicerol O-Aciltransferase/metabolismo , Redes e Vias Metabólicas/fisiologia
16.
Methods ; 109: 81-91, 2016 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-27389303

RESUMO

Singlet molecular oxygen, O2(a1Δg), is a Reactive Oxygen Species, ROS, that acts as a signaling and/or perturbing agent in mammalian cells, influencing processes that range from cell proliferation to cell death. Although the importance of O2(a1Δg) in this regard is acknowledged, an understanding of the targets and mechanisms of O2(a1Δg) action is inadequate. Thus, methods that better facilitate studies of O2(a1Δg) in mammalian cells are highly desired. This is particularly important because, as a consequence of its chemistry in a cell, O2(a1Δg) can spawn the generation of other ROS (e.g., the hydroxyl radical) that, in turn, can have a unique influence on cell behavior and function. Therefore, exerting better control and specificity in O2(a1Δg) experiments ultimately reduces the number of variables in general studies to unravel the details of ROS-dependent cell dynamics. In this article, we summarize our recent efforts to produce O2(a1Δg) with increased control and selectivity in microscope-based single-cell experiments. The topics addressed include (1) two-photon excitation of a photosensitizer using a focused laser to create a spatially-localized volume of O2(a1Δg) with sub-cellular dimensions, (2) protein-encapsulated photosensitizers that can be localized in a specific cellular domain using genetic engineering, and (3) direct excitation of dissolved oxygen in sensitizer-free experiments to selectively produce O2(a1Δg) at the expense of other ROS. We also comment on our recent efforts to monitor O2(a1Δg) in cells and to monitor the cell's response to O2(a1Δg).


Assuntos
Estresse Oxidativo , Fármacos Fotossensibilizantes/isolamento & purificação , Espécies Reativas de Oxigênio/isolamento & purificação , Oxigênio Singlete/isolamento & purificação , Animais , Lasers , Luz , Mamíferos , Oxirredução , Fármacos Fotossensibilizantes/química , Espécies Reativas de Oxigênio/química , Oxigênio Singlete/química
17.
Phys Chem Chem Phys ; 18(21): 14520-30, 2016 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-27173474

RESUMO

A simple procedure for the preparation of giant vesicles using surface active ionic liquids (SAILs) has been provided in this paper. SAILs, used to form vesicles, were synthesized by replacing the cationic part of Aerosol OT (AOT) with cations having alkyl chains of different lengths (ammonium and imidazolium cations). The number of carbons in the alkyl chains of the cations was varied from eight to sixteen. From the observed results, the formation of giant vesicles is found to be dependent on the alkyl chain length as well as the organic moieties of the respective cations. These giant vesicles were characterized using fluorescence lifetime imaging microscopy (FLIM). The conformational dynamics of bovine serum albumin (BSA) inside these giant vesicles was determined using fluorescence correlation spectroscopy (FCS) to get an idea about the protein dynamics in a constrained environment. The interaction of the giant vesicles with the protein was confirmed by the change in the diffusion coefficient and the conformational fluctuation time.


Assuntos
Líquidos Iônicos/química , Lipossomos/química , Soroalbumina Bovina/química , Animais , Cátions/química , Bovinos , Hidrodinâmica , Imidazóis/química , Lipossomos/metabolismo , Microscopia de Fluorescência , Conformação Proteica , Espectrometria de Fluorescência
18.
Front Microbiol ; 7: 432, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27065986

RESUMO

The current scenario in renewable energy is focused on development of alternate and sustainable energy sources, amongst which microalgae stands as one of the promising feedstock for biofuel production. It is well known that microalgae generate much larger amounts of biofuels in a shorter time than other sources based on plant seeds. However, the greatest challenge in a transition to algae-based biofuel production is the various other complications involved in microalgal cultivation, its harvesting, concentration, drying and lipid extraction. Several green microalgae accumulate lipids, especially triacylglycerols (TAGs), which are main precursors in the production of lipid. The various aspects on metabolic pathway analysis of an oleaginous microalgae i.e., Chlamydomonas reinhardtii have elucidated some novel metabolically important genes and this enhances the lipid production in this microalgae. Adding to it, various other aspects in metabolic engineering using OptFlux and effectual bioprocess design also gives an interactive snapshot of enhancing lipid production which ultimately improvises the oil yield. This article reviews the current status of microalgal based technologies for biofuel production, bioreactor process design, flux analysis and it also provides various strategies to increase lipids accumulation via metabolic engineering.

19.
Biotechnol J ; 11(3): 303-14, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26844808

RESUMO

Exploring the efficiency of algae to produce remarkable products can be directly benefitted by studying its mechanism at systems level. Recent advents in biotechnology like flux balance analysis (FBA), genomics and in silico proteomics minimize the wet lab exertion. It is understood that FBA predicts the metabolic products, metabolic pathways and alternative pathway to maximize the desired product, and these are key components for microalgae bio-engineering. This review encompasses recent transgenesis techniques and metabolic engineering strategies applied to different microalgae for improving different traits. Further it also throws light on RNAi and riboswitch engineering based methods which may be advantageous for high throughput microalgal research. A valid and optimally designed microalga can be developed where every engineering strategies meet each other successfully and will definitely fulfill the market needs. It is also to be noted that Omics (viz. genetic and metabolic manipulation with bioinformatics) should be integrated to develop a strain which could prove to be a futuristic solution for sustainable development for energy.


Assuntos
Conservação dos Recursos Naturais/métodos , Engenharia Metabólica/métodos , Microalgas/crescimento & desenvolvimento , Bioengenharia/métodos , Simulação por Computador , Técnicas de Transferência de Genes , Genômica , Microalgas/genética , Proteômica , Riboswitch/genética
20.
Inorg Chem ; 54(15): 7368-80, 2015 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-26173067

RESUMO

Cadmium selenide quantum dots of 2.2-2.3 nm diameter were prepared by phosphorus-free methods using oleic acid as stabilizing surface ligand. Ligand exchange monitored quantitatively by (1)H NMR spectroscopy gave an estimate of 30-38 monodentate ligands per nanocrystal, with a ligand density of 1.8-2.3 nm(-2). The extent of ligand exchange with macrocycles carrying one or more functional groups was investigated, with the aim of producing nanocrystal-macrocycle conjugates with a limited number of coligands. Metal-free porphyrins are able to sequester the Cd(2+) ions from the Cd(oleate)2 outer layer of the nanocrystals. Zinc porphyrin complexes carrying one carboxylate function displace oleate efficiently to give porphyrin/CdSe composites with porphyrins stacked upright on the crystal surface. Porphyrins with four potential ligating sites are able to bind to the crystal surface only if the donors are at the end of sufficiently long and flexible tethers. High-dilution methods allowed the synthesis and isolation of well-defined composites of composition [CdSe{porphyrin}2], where porphyrin = 5,10,15,20-tetrakis{3-(carboxy-n-alkyloxy)phenyl}porphyrinato zinc (n = 5 or 10) and 5,10,15,20-tetrakis{3-(11-undecenyloxythiol)phenyl}porphyrinato zinc. Comparison of the composition data obtained by (1)H NMR spectroscopy with luminescence quenching behavior suggests a dependence of quenching efficiency on the tether length. Luminescence quenching was also observed for porphyrins that, according to (1)H NMR results, do not undergo surface ligand exchange.

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