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1.
Comparative evaluation of acid and alkaline sulfite pretreatments for enzymatic saccharification of bagasses from three different sugarcane hybrids.
Monte, JR, Laurito-Friend, DF, Mussatto, SI, Ferraz, A, Milagres, AMF
Biotechnology progress. 2018;(4):944-951
Abstract
Sugarcane bagasses from three experimental sugarcane hybrids and a mill-reference sample were used to compare the efficiency and mode of action of acid and alkaline sulfite pretreatment processes. Varied chemical loads and reaction temperatures were used to prepare samples with distinguished characteristics regarding xylan and lignin removals, as well as sulfonation levels of residual lignins. The pretreatment with low sulfite loads (5%) under acidic conditions (pH 2) provided maximum glucose yield of 70% during enzymatic hydrolysis with cellulases (10 FPU/g) and β-glucosidases (20 UI/g bagasse). In this case, glucan enzymatic conversion from pretreated materials was mostly associated with extensive xylan removal (70-100%) and partial delignification occurred during the pretreatment. The use of low sulfite loads under acidic conditions required pretreatment temperatures of 160°C. In contrast, at a lower pretreatment temperature (120°C), alkaline sulfite process achieved similar glucan digestibility, but required a higher sulfite load (7.5%). Residual xylans from acid pretreated materials were almost completely hydrolysed by commercial enzymes, contrasting with relatively lower xylan to xylose conversions observed in alkaline pretreated samples. Efficient xylan removal during acid sulfite pretreatment and during enzymatic digestion can be useful to enhance glucan accessibility and digestibility by cellulases. Alkaline sulfite process also provided substrates with high glucan digestibility, mainly associated with delignification and sulfonation of residual lignins. The results demonstrate that temperature, pH, and sulfite can be combined for reducing lignocellulose recalcitrance and achieve similar glucan conversion rates in the alkaline and acid sulfite pretreated bagasses. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:944-951, 2018.
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2.
Asymmetric cellulose triacetate is a safe and effective alternative for online haemodiafiltration.
Albalate Ramón, M, Martínez Miguel, P, Bohorquez, L, de Sequera, P, Bouarich, H, Pérez-García, R, Rodríguez Puyol, D, Barril, G, Sánchez Tomero, JA, Giorgi, M, et al
Nefrologia. 2018;(3):315-320
Abstract
BACKGROUND In post-dilution haemodiafiltration only synthetic membranes have been used to date. Asymmetric cellulose triacetate (ATA™) is now available, whose characteristics are suitable for this technique. OBJECTIVES To describe the in vivo performance and behaviour of this membrane, to identify its depurative effectiveness, use in clinical practice and its biocompatibility, both acute and after one month of treatment. METHODS Observational prospective study of 23 patients who were dialysed for 4 weeks using an ATA™ membrane and who maintained their prior regimen. RESULTS A total of 287 sessions were performed and 264 complete sessions were collected. With an effective time of 243.7 (17.6) min and a mean blood flow of 371.7 (23) ml/min, an average Kt of 56.3 (5.3) l was observed, as well as a convection volume of 27.1 (4.2) l, a filtration fraction of 29.9 (3.7) %, a urea reduction ratio (RR) of 81 (5.2) %, a creatinine RR of 74.7 (4.6) %, a β2-microglobulin RR of 76.5 (4.8) % and a retinol binding protein RR of 18.6 (7.6) %. There were no technical problems or alarms. Changing the heparin dosage was not necessary. No increases in C3a or C5a concentrations or leukopenia were observed in the first 30min of the session. Neither the monocyte subpopulations nor IL-β1 or IL-6 were significantly altered after one month of treatment. CONCLUSIONS The new ATA™ membrane achieves adequate Kt and convection volume, without technical problems and with good biocompatibility and inflammatory profiles. It is therefore a valid option for post-dilution haemodiafiltration, particularly in patients allergic to synthetic membranes.
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3.
Adsorption of Protein-Bound Uremic Toxins Through Direct Hemoperfusion With Hexadecyl-Immobilized Cellulose Beads in Patients Undergoing Hemodialysis.
Yamamoto, S, Sato, M, Sato, Y, Wakamatsu, T, Takahashi, Y, Iguchi, A, Omori, K, Suzuki, Y, Ei, I, Kaneko, Y, et al
Artificial organs. 2018;(1):88-93
Abstract
An accumulation of protein-bound uremic toxins (PBUTs) is one of major reasons for development of uremia-related complications. We examined the PBUT removal ability of a hexadecyl-immobilized cellulose bead (HICB)-containing column for patients undergoing hemodialysis. Adsorption of indoxyl sulfate (IS), a representative PBUT, to HICBs was examined in vitro. The HICB column was used in patients undergoing hemodialysis for direct hemoperfusion with a regular hemodialyzer. The serum IS, indole acetic acid (IAA), phenyl sulfate (PhS), and p-cresyl sulfate (PCS) levels were measured before and after passing the column. HICBs adsorbed protein-free (free) IS in a dose- and time-dependent manner in vitro (55.4 ± 1.4% adsorption of 1 millimolar, 251 µg/mL, IS for 1 h). In clinical studies, passing the HICB-containing column decreased the serum level of free IS, IAA, PhS, and PCS levels significantly (by 34.4 ± 30.0%, 34.8 ± 25.4%, 28.4 ± 18.0%, and 34.9 ± 22.1%, respectively), but not protein-bound toxins in maintenance hemodialysis patients. HICBs absorbed some amount of free PBUTs, but the clinical trial to use HICB column did not show effect to reduce serum PBUTs level in hemodialysis patients. Adsorption treatment by means of direct hemoperfusion with regular hemodialysis may become an attractive blood purification treatment to increase PBUT removal when more effective materials to adsorb PBUTs selectively will be developed.
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4.
Bacterial cellulose skin masks-Properties and sensory tests.
Pacheco, G, de Mello, CV, Chiari-Andréo, BG, Isaac, VLB, Ribeiro, SJL, Pecoraro, É, Trovatti, E
Journal of cosmetic dermatology. 2018;(5):840-847
Abstract
BACKGROUND Bacterial cellulose (BC) is a versatile material produced by microorganisms in the form of a membranous hydrogel, totally biocompatible, and endowed with high mechanical strength. Its high water-holding capacity based on its highly porous nanofibrillar structure allows BC to incorporate and to release substances very fast, thus being suitable for the preparation of skincare masks. AIMS The preparation and characterization of cosmetic masks based on BC membranes and active cosmetics. METHODS The masks were prepared by the simple incorporation of the cosmetic actives into BC membranes, used as a swelling matrix. The masks were characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), sensory tests, and skin moisture tests on volunteers. RESULTS The results of sensory tests revealed the good performance of BC, being considered effective by the panel of volunteers, specially for adhesion to the skin (7.7 at the score scale), and improvement of the skin moisture (the hydration effect increased 76% in 75% of the volunteers that used vegetable extract mask formulation [VEM]), or a decrease in skin hydration (80% of the volunteers showed 32.6% decrease on skin hydration using propolis extract formulation [PEM] treatment), indicating the BC nanofiber membranes can be used to skincare applications. CONCLUSION The results demonstrate the BC can be used as an alternative support for cosmetic actives for skin treatment.
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5.
Effect of Irvingia gabonensis on Metabolic Syndrome, Insulin Sensitivity, and Insulin Secretion.
Méndez-Del Villar, M, González-Ortiz, M, Martínez-Abundis, E, Pérez-Rubio, KG, Cortez-Navarrete, M
Journal of medicinal food. 2018;(6):568-574
Abstract
The aim of this study was to evaluate the effect of Irvingia gabonensis on metabolic syndrome (MetS), insulin sensitivity, and insulin secretion. A randomized, double-blind, placebo-controlled clinical trial was performed in 24 patients with MetS in accordance with the International Diabetes Federation criteria. Twelve patients received I. gabonensis (150 mg) twice a day during 90 days, and 12 patients received placebo. Glucose and insulin concentrations were measured during a 2-h oral glucose tolerance test. Also, lipid profile, creatinine, uric acid, and hepatic enzymes were determined. The area under the curve (AUC) of glucose and insulin, total insulin secretion, first phase of insulin secretion, and insulin sensitivity were calculated. Data were tested using non-parametric tests. The Ethics Committee approved the protocol. After I. gabonensis administration, significant decreases in waist circumference (WC) (94.0 ± 8.0 vs. 91.0 ± 8.2 cm, P < .01), glucose 90' (10.0 ± 2.5 vs. 8.6 ± 2.7 mmol/L, P < .05), glucose 120' (8.8 ± 2.4 vs. 7.6 ± 2.7 mmol/L, P < .05), triglycerides (2.5 ± 1.2 vs. 2.0 ± 1.1 mmol/L, P < .05), very low-density lipoproteins (VLDL) (0.5 ± 0.2 vs. 0.4 ± 0.2 mmol/L, P < .05), and AUC of glucose (694 ± 142 vs. 629 ± 172 mmol/L/min, P < .05) were found. Seven patients (58.3%) of the I. gabonensis group showed remission of MetS and two patients (16.7%) of the placebo group (P = .045). I. gabonensis lead to remission of MetS in 58.3% of the patients and significantly decreased WC, glucose 90', glucose 120', triglycerides, VLDL, and AUC of glucose.
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6.
[Optimization of Nasal Drug Absorption from Powder Formulations: The Feasibility of Controlling Drug Absorption by the Use of Pharmaceutical Excipients].
Tanaka, A
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan. 2018;(12):1467-1472
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Abstract
Nasal application of powder formulations has garnered attention because of its significant potential for systemic drug delivery. Because a powder drug must first diffuse from the formulation and dissolve in the nasal cavity fluid before transepithelial permeation, dissolution and diffusion are distinct but important factors for nasal drug absorption. Since the formulation is directly administered onto the nasal mucosal surface, the effect of excipients on drug absorption may be significant. Therefore, the influence of excipients on nasal drug absorption was evaluated. Three types of hydroxypropyl cellulose (HPC) [HPC (SL), HPC (M), and HPC (H)], lactose, and sodium chloride (NaCl) were used as excipients. Warfarin (WF), piroxicam (PXC), sumatriptan (STP), and norfloxacin (NFX) were selected as model drugs. HPC (M) enhanced the absorption of PXC, while both HPC (M) and HPC (H) enhanced the absorption of STP. All three HPCs failed to enhance the absorption of WF. An increase in the polymerization degree of HPCs decreased the diffusion of drugs in HPC solutions, but prolonged their nasal retention. Lactose and NaCl increased the fluid volume on the nasal mucosal surface by increasing the osmotic pressure, thereby enhancing the nasal absorption of PXC and NFX; however, lactose and NaCl accelerated the nasal clearance of these. These results indicate that nasal drug absorption from powder formulations can be controlled by excipients.
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7.
Chloroplasts as Cellular Factories for the Cost-effective Production of Cellulases.
Khan, MO, Mehmood, MA, Mukhtar, Z, Ahmad, N
Protein and peptide letters. 2018;(2):129-135
Abstract
Chloroplasts are vital photosynthetic organelles in plant cells that carry out several important cellular functions including synthesis of amino acids, fatty acids, and lipids and metabolism of nitrogen, starch, and Sulphur to sustain the homeostasis in plants. These organelles have got their own genome, and related genetic machinery to synthesize required proteins for various plant functions. Genetic manipulations of the chloroplast genome for different biotech applications has been of great interest due to desired features including the availability of operonal mode of gene expression, high copy number, and maternal mode of inheritance (in the most field crops). Their capacity to often express transgenes at high levels make it a cost-effective platform for the production of foreign proteins, particularly high-value targets of industrial importance, at large scale. This article reviews briefly the research work carried out to produce cellulolytic enzymes in higher plant chloroplasts. The challenges and future opportunities for the same are also discussed.
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Sticking to cellulose: exploiting Arabidopsis seed coat mucilage to understand cellulose biosynthesis and cell wall polysaccharide interactions.
Griffiths, JS, North, HM
The New phytologist. 2017;(3):959-966
Abstract
The cell wall defines the shape of cells and ultimately plant architecture. It provides mechanical resistance to osmotic pressure while still being malleable and allowing cells to grow and divide. These properties are determined by the different components of the wall and the interactions between them. The major components of the cell wall are the polysaccharides cellulose, hemicellulose and pectin. Cellulose biosynthesis has been extensively studied in Arabidopsis hypocotyls, and more recently in the mucilage-producing epidermal cells of the seed coat. The latter has emerged as an excellent system to study cellulose biosynthesis and the interactions between cellulose and other cell wall polymers. Here we review some of the major advances in our understanding of cellulose biosynthesis in the seed coat, and how mucilage has aided our understanding of the interactions between cellulose and other cell wall components required for wall cohesion. Recently, 10 genes involved in cellulose or hemicellulose biosynthesis in mucilage have been identified. These discoveries have helped to demonstrate that xylan side-chains on rhamnogalacturonan I act to link this pectin directly to cellulose. We also examine other factors that, either directly or indirectly, influence cellulose organization or crystallization in mucilage.
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Regulation of cellulose synthesis in response to stress.
Kesten, C, Menna, A, Sánchez-Rodríguez, C
Current opinion in plant biology. 2017;:106-113
Abstract
The cell wall is a complex polysaccharide network that provides stability and protection to the plant and is one of the first layers of biotic and abiotic stimuli perception. A controlled remodeling of the primary cell wall is essential for the plant to adapt its growth to environmental stresses. Cellulose, the main component of plant cell walls is synthesized by plasma membrane-localized cellulose synthases moving along cortical microtubule tracks. Recent advancements demonstrate a tight regulation of cellulose synthesis at the primary cell wall by phytohormone networks. Stress-induced perturbations at the cell wall that modify cellulose synthesis and microtubule arrangement activate similar phytohormone-based stress response pathways. The integration of stress perception at the primary cell wall and downstream responses are likely to be tightly regulated by phytohormone signaling pathways in the context of cellulose synthesis and microtubule arrangement.
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Conductive microbial cellulose as a novel biocathode for Cr (VI) bioreduction.
Loloei, M, Rezaee, A, Roohaghdam, AS, Aliofkhazraei, M
Carbohydrate polymers. 2017;:56-61
Abstract
In the present study, microbial cellulose (MC) as a carbohydrate polymer was made conductive by oxidative polymerization with aniline. Sulfate-reducing bacteria (SRB) were immobilized on the surface of the conductive biopolymer, and this was used as a biocathode in a bioreduction process to reduce Cr (VI) as a model of heavy metals. The results of Fourier transform infrared analysis confirmed that the polyaniline was distributed on the cellulose surface. The maximum tensile stress of the conductive biopolymer was obtained 23MPa using calculating Young's modulus. A current density of 60mA/m2 was determined as optimal, and an increase in pH from 5 to 7 significantly reduced the required time for reduction of Cr (VI). The system reached >99% removal of Cr (VI) within 1.5h at pH 7. Kinetic experiment studies showed a high constant rate (mean Kobs 0.78, R2 0.95). The results showed that the conductive MC can be used as an appropriate bioelectrode to reduce Cr (VI) in bioelectrochemical processes. It is expected that experimental results could be used as a reference for the utilization of MC in bioelectrochemical systems.