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- ArticleDai Z, Qin F, Zhao H, Tian F, Liu Y, Chen R.Nanoscale. 2015 Jul 28;7(28):11991-9.Hierarchical Bi(3.64)Mo(0.36)O(6.55)/Bi2MoO6 isotype heterostructures were successfully prepared via a one-pot hydrothermal route by using Bi2O3 porous nanospheres as a sacrificial template. By tuning the reaction time, the formation process of the Bi(3.64)Mo(0.36)O(6.55)/Bi2MoO6 heterostructure involving Mo etching, phase transition and anisotropic growth was clearly identified. More importantly, the Bi(3.64)Mo(0.36)O(6.55)/Bi2MoO6 heterostructure displayed remarkably enhanced photocatalytic activity for dye photodegradation than pure phase bismuth molybdate due to the efficient electron-hole separation and the interfacial photogenerated hole migration from inside the Bi(3.64)Mo(0.36)O(6.55) layer to outside the Bi2MoO6 layer. The opposite hole migration from the outer layer to the inner layer was also detected in Bi2O3/Bi2WO6 heterostructures, which resulted in the decrease of photocatalytic activity, further verifying the importance of hole migration direction. This work provides a novel route to fabricate heterostructured photocatalysts, as well as gives a strategy for mediating the charge migration to improve photocatalytic performance.
- ArticleJian MJ, Chung HY, Chang CK, Hsieh SS, Lin JC, Yeh KM, Chen CW, Chang FY, Hung KS, Liu MT, Yang JR, Chang TY, Tang SH, Perng CL, Shang HS.PeerJ. 2021;9:e11991.BACKGROUND: There is a global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Information on viral genomics is crucial for understanding global dispersion and for providing insight into viral pathogenicity and transmission. Here, we characterized the SARS-CoV-2 genomes isolated from five travelers who returned to Taiwan from the United States of America (USA) between March and April 2020.
METHODS: Haplotype network analysis was performed using genome-wide single-nucleotide variations to trace potential infection routes. To determine the genetic variations and evolutionary trajectory of the isolates, the genomes of isolates were compared to those of global virus strains from GISAID. Pharyngeal specimens were confirmed to be SARS-CoV-2-positive by RT-PCR. Direct whole-genome sequencing was performed, and viral assemblies were subsequently uploaded to GISAID. Comparative genome sequence and single-nucleotide variation analyses were performed.
RESULTS: The D614G mutation was identified in imported cases, which separated into two clusters related to viruses originally detected in the USA. Our findings highlight the risk of spreading SARS-CoV-2 variants through air travel and the need for continued genomic tracing for the epidemiological investigation and surveillance of SARS-CoV-2 using viral genomic data.
CONCLUSIONS: Continuous genomic surveillance is warranted to trace virus circulation and evolution in different global settings during future outbreaks. - ArticleChakraborty A, Lingampalli SR, Kumari A, Ribas J, Ribas-Arino J, Maji TK.Inorg Chem. 2014 Nov 17;53(22):11991-2001.This Article reports the syntheses, structural characterization, and magnetic studies of four different Cu(II)-azido compounds based on imidazole or substituted imidazole ligand. The compounds, [Cu2(μ1,1-N3)2(EtimiH)4(ClO4)2] (1) (EtimiH = 2-ethylimidazole), [Cu2(μ-Meimi(-))(MeimiH)2(μ1,1-N3)2(μ1,3-N3)]n (2) (MeimiH = 2-methylimidazole; μ-Meimi(-) is the bridging mononegative anion of 2-methylimidazole), [Cu2(μ-imi(-))(imiH)2(μ1,1-N3)2(μ1,3-N3)]n (3), and [{Cu2(μ1,1-N3)2(μ1,3-N3)(μ-imi(-))(imiH)3}·H2O]n (4) (imiH = imidazole; μ-imi(-) = bridging mononegative anion of imidazole), have been synthesized by the self-assembly of Cu(II) salts, azide ion, and the corresponding imidazole bridging ligands. By changing the substitution on the second linker (imidazole or substituted imidazole) and varying synthetic conditions, diverse structural and magnetic features have been achieved in compounds 1-4. Compound 1 has a double end-on azido bridged dinuclear core, while the other compounds (2-4) have 2D networks. Compound 2 and 3 contain 1D chains with alternate μ1,1-N3 and μ-Meimi(-) bridging, and such chains are further connected through a μ1,3-N3 bridge to result in the formation of the 2D network. Compound 4 is a novel 2D coordination polymer consisting of a zigzag 1D coordination chain having (μ1,1-N3)2, μ-imi(-), and (μ1,3-N3)2 bridging groups and the chains undergo bridging through a μ1,3-N3 group resulting in the 2D network. Temperature dependent magnetic measurements show diverse magnetic properties of 1-4. Such versatile magnetic behaviors have been correlated to the respective bridging mode of azide and the corresponding imidazole bridging ligands.
- ArticleNour H, Daoui O, Abchir O, ElKhattabi S, Belaidi S, Chtita S.Heliyon. 2022 Dec;8(12):e11991.Butyrylcholinesterase is an acetylcholine-degrading enzyme involved in the memorization process, which is becoming an interesting target for the symptomatic treatment of Alzheimer's disease. In the present investigation, the structure-activity relationship of a set of Liquiritigenin derivatives recently revealed to be Butyrylcholinesterase inhibitors was studied basing on comparative field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMISA). As a result, performant models with high predictive capability have been developed (CoMFA model: R2 = 0.91, Q2 = 0.62, R2 pred = 0.85; CoMISA model: R2 = 0.92, Q2 = 0.59, R2 pred = 0.83) and implemented to design new Liquiritigenin derivatives with improved activity. Besides, the affinity of the designed derivatives towards the active site of Butyrylcholinesterase, was confirmed by molecular docking and molecular dynamics studies. Moreover, they exhibited good pharmacokinetics properties. Accordingly, the outcomes of the present investigations can provide important direction for the development of new anti-Alzheimer's drug candidates.
- ArticleBordbar S, Li Z, Lotfibakhshaiesh N, Ai J, Tavassoli A, Beheshtizadeh N, Vainieri L, Khanmohammadi M, Sayahpour FA, Baghaban Eslaminejad M, Azami M, Grad S, Alini M.Sci Rep. 2024 05 25;14(1):11991.Physiochemical tissue inducers and mechanical stimulation are both efficient variables in cartilage tissue fabrication and regeneration. In the presence of biomolecules, decellularized extracellular matrix (ECM) may trigger and enhance stem cell proliferation and differentiation. Here, we investigated the controlled release of transforming growth factor beta (TGF-β1) as an active mediator of mesenchymal stromal cells (MSCs) in a biocompatible scaffold and mechanical stimulation for cartilage tissue engineering. ECM-derived hydrogel with TGF-β1-loaded alginate-based microspheres (MSs) was created to promote human MSC chondrogenic development. Ex vivo explants and a complicated multiaxial loading bioreactor replicated the physiological conditions. Hydrogels with/without MSs and TGF-β1 were highly cytocompatible. MSCs in ECM-derived hydrogel containing TGF-β1/MSs showed comparable chondrogenic gene expression levels as those hydrogels with TGF-β1 added in culture media or those without TGF-β1. However, constructs with TGF-β1 directly added within the hydrogel had inferior properties under unloaded conditions. The ECM-derived hydrogel group including TGF-β1/MSs under loading circumstances formed better cartilage matrix in an ex vivo osteochondral defect than control settings. This study demonstrates that controlled local delivery of TGF-β1 using MSs and mechanical loading is essential for neocartilage formation by MSCs and that further optimization is needed to prevent MSC differentiation towards hypertrophy.
- ArticleRehman A, Saeed A, Asad W, Khan I, Hayat A, Rehman MU, Shah TA, Sitotaw B, Dawoud TM, Bourhia M.Sci Rep. 2023 07 25;13(1):11991.Starch is added to the fabric surface to secure weaving process. During finishing these sized particles are removed from the fabric and prepared it for printing and dyeing. Chemicals de-sizing agents damage fabric surfaces and reduce the quality of the product. An alternative to these conventional desizing agents is the use of biological molecules i.e. enzymes. The current study compares traditional de-sizing to bio-based de-sizing methods, as well as the optimization of fabric desizing settings using crude amylase. Amylase-producing Bacillus cereus AS2 was isolated from indigenous soil samples. The maximal fermentative de-sizing capability was discovered at 72 h, with no fabric surface degradation. Chemical desizing showed that the fabric lost all sizing agents to TEGEWA scale 9 within 1 h in presence of 5N HCl. Optimal studies for desizing showed that 1000 IU/ml of amylase resulted in maximum de-sizing within 15 h at 60 °C and 0.5% Triton-X. Water absorbance and weight loss, both parameters were used to check the desizing efficacy and it was found that de-sizing to same scale was occurred in the case of enzyme as well as commercially desized fabric. Enzyme desized cloth was found to be free of any starch particles in SEM micrographs, identical to industrially de-sized fabric, ensuring bioprocess efficacy.
- ArticleMeyer JJ, Gokul A, Wang MTM, Sung J, Craig JP.Sci Rep. 2022 07 14;12(1):11991.The purpose of this study was to evaluate any alterations in the tear film and ocular surface beyond the early postoperative period following penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK). This cross-sectional, contralateral-eye study compared ocular surface and tear film parameters of eyes with a previous PK or DALK in one eye and no prior surgery in the contralateral eye. Overall, 14 (87.5%) participants underwent PK, and 2 (12.5%) underwent DALK using a mechanical dissection. The median time from surgery was 3.4 years (range 1.5 to 38.7 years). The indication for unilateral keratoplasty was keratoconus in 15 (94%) participants, and corneal scarring in 1 (6%) eye, secondary to microbial keratitis. Operated eyes exhibited poorer non-invasive tear film breakup time, lower corneal sensitivity, lower sub-basal nerve density and more severe fluorescein staining scores than unoperated fellow eyes (all Q < 0.05). There were no significant differences in tear film lipid layer quality, tear meniscus height, conjunctival hyperaemia, lissamine green staining score, or meibography grade between operated and fellow eyes (all Q ≥ 0.20). Higher corneal esthesiometry threshold (lower corneal sensitivity) was correlated with shorter non-invasive tear film breakup time (Spearman's rho = - 0.361, p = 0.04) and increased fluorescein staining score (Spearman's rho = 0.417, p = 0.02). Keratoplasty can induce persistent changes in the ocular surface and tear film, including: increased fluorescein staining, decreased tear film breakup time, decreased corneal sub-basal nerve plexus density, and reduced corneal sensitivity.
- ArticleBradaric BD, Tresselt DB.Educ Inf Technol (Dordr). 2022;27(9):11991-12002.Moving to a virtual platform can introduce barriers beyond access and stability of technology, which may influence students' academic performance. The aim of this study was to identify factors, both personal and technology-related, that students and faculty perceived as contributors to academic performance. Enrolled students and teaching faculty in the Bachelor of Science programs at Rush University were surveyed. Analysis of survey results indicated that mental health and finances hindered students' performance, whereas faculty reported that technology accessibility and stability was the greatest contributor to students' performance. Both groups reported that at-home learning environment contributed to students' academic performance. These results provided insight into factors that impact student academic performance, allowing for appropriate changes to courses and overall curriculum to ensure undergraduates' learning and retention of course material.
- ArticleNattich-Rak M, Adamczyk Z, Wasilewska M, Sadowska M.Langmuir. 2013 Sep 24;29(38):11991-2002.Colloid particle deposition was applied to characterize bovine and human fibrinogen (Fb) monolayers on mica produced by controlled adsorption under diffusion transport at pH 3.5. The surface concentration of Fb was determined by AFM enumeration of single molecules adsorbed over the substrate surface. The electrokinetic properties of Fb monolayers for various ionic strength were studied using the in situ streaming potential measurements. It was shown that Fb adsorbs irreversibly on mica for a broad range of ionic strength of 4 × 10(-4) to 0.15 M, NaCl. The overcharging of initially negative mica surface occurred for fibrinogen surface concentrations higher than 1400 μm(-2). The orientation of fibrinogen molecules in the monolayers was evaluated by the colloid deposition method involving negatively charged polystyrene latex microspheres, 820 nm in diameter. An anomalous deposition of negative latex particles on substrates exhibiting a negative zeta potential was observed, which contradicts the mean-field DLVO predictions. Measurable deposition was observed even at low ionic strength where the minimum approach distance of latex particles to the interface exceeds 70 nm (for 6 × 10(-4) M NaCl). This confirms that, at this pH, fibrinogen molecules adsorb end-on on mica assuming extended conformations with the positive charge located mostly in the end part of the αA chains. This agrees with previous experimental and theoretical results discussed in the literature (Santore, M. M.; Wertz Ch. F. Protein spreading kinetics at liquid-solid interfaces via an adsorption probe method. Langmuir 2005, 21, 10172-10178 (experimental); Adamczyk, Z.; Barbasz, J.; Cieśla, M.; Mechanisms of fibrinogen adsorption at solid substrates. Langmuir, 2011, 25, 6868-6878 (theoretical)). This unusual latex deposition on Fb monolayers was quantitatively interpreted in terms of the model developed in ref 55 (Jin, X.; Wang, N. H. L.; Tarjus, G.; Talbot, J. Irreversible adsorption on nonuniform surfaces: the random site model. J. Phys. Chem. 1993, 97, 4256-4258). It was concluded that the colloid deposition method is an efficient tool for revealing protein adsorption mechanisms at solid/electrolyte interfaces.
- ArticleTwo RmlC homologs catalyze dTDP-4-keto-6-deoxy-D-glucose epimerization in Pseudomonas putida KT2440.Koller F, Lassak J.Sci Rep. 2021 06 07;11(1):11991.L-Rhamnose is an important monosaccharide both as nutrient source and as building block in prokaryotic glycoproteins and glycolipids. Generation of those composite molecules requires activated precursors being provided e. g. in form of nucleotide sugars such as dTDP-β-L-rhamnose (dTDP-L-Rha). dTDP-L-Rha is synthesized in a conserved 4-step reaction which is canonically catalyzed by the enzymes RmlABCD. An intact pathway is especially important for the fitness of pseudomonads, as dTDP-L-Rha is essential for the activation of the polyproline specific translation elongation factor EF-P in these bacteria. Within the scope of this study, we investigated the dTDP-L-Rha-biosynthesis route of Pseudomonas putida KT2440 with a focus on the last two steps. Bioinformatic analysis in combination with a screening approach revealed that epimerization of dTDP-4-keto-6-deoxy-D-glucose to dTDP-4-keto-6-deoxy-L-mannose is catalyzed by the two paralogous proteins PP_1782 (RmlC1) and PP_0265 (RmlC2), whereas the reduction to the final product is solely mediated by PP_1784 (RmlD). Thus, we also exclude the distinct RmlD homolog PP_0500 and the genetically linked nucleoside diphosphate-sugar epimerase PP_0501 to be involved in dTDP-L-Rha formation, other than suggested by certain databases. Together our analysis contributes to the molecular understanding how this important nucleotide-sugar is synthesized in pseudomonads.
- ArticleBackus AR, Bosch SE, Ekman M, Grabovetsky AV, Doeller CF.Nat Commun. 2016 06 21;7:11991.The ability to form associations between a multitude of events is the hallmark of episodic memory. Computational models have espoused the importance of the hippocampus as convergence zone, binding different aspects of an episode into a coherent representation, by integrating information from multiple brain regions. However, evidence for this long-held hypothesis is limited, since previous work has largely focused on representational and network properties of the hippocampus in isolation. Here we identify the hippocampus as mnemonic convergence zone, using a combination of multivariate pattern and graph-theoretical network analyses of functional magnetic resonance imaging data from humans performing an associative memory task. We observe overlap of conjunctive coding and hub-like network attributes in the hippocampus. These results provide evidence for mnemonic convergence in the hippocampus, underlying the integration of distributed information into episodic memory representations.
- ArticleBiering SB, Huang A, Vu AT, Robinson LR, Bradel-Tretheway B, Choi E, Lee B, Aguilar HC.J Virol. 2012 Nov;86(22):11991-2002.Nipah virus (NiV) is the deadliest known paramyxovirus. Membrane fusion is essential for NiV entry into host cells and for the virus' pathological induction of cell-cell fusion (syncytia). The mechanism by which the attachment glycoprotein (G), upon binding to the cell receptors ephrinB2 or ephrinB3, triggers the fusion glycoprotein (F) to execute membrane fusion is largely unknown. N-glycans on paramyxovirus glycoproteins are generally required for proper protein conformational integrity, transport, and sometimes biological functions. We made conservative mutations (Asn to Gln) at the seven potential N-glycosylation sites in the NiV G ectodomain (G1 to G7) individually or in combination. Six of the seven N-glycosylation sites were found to be glycosylated. Moreover, pseudotyped virions carrying these N-glycan mutants had increased antibody neutralization sensitivities. Interestingly, our results revealed hyperfusogenic and hypofusogenic phenotypes for mutants that bound ephrinB2 at wild-type levels, and the mutant's cell-cell fusion phenotypes generally correlated to viral entry levels. In addition, when removing multiple N-glycans simultaneously, we observed synergistic or dominant-negative membrane fusion phenotypes. Interestingly, our data indicated that 4- to 6-fold increases in fusogenicity resulted from multiple mechanisms, including but not restricted to the increase of F triggering. Altogether, our results suggest that NiV-G N-glycans play a role in shielding virions against antibody neutralization, while modulating cell-cell fusion and viral entry via multiple mechanisms.
- ArticleAlharbi AMD, Alhazmi AMS.Cureus. 2020 Dec 09;12(12):e11991.Diabetes mellitus is a common disease in Saudi Arabia and globally, with some studies reporting about 30% prevalence among the Saudi population. Diabetic retinopathy (DR) is the leading cause of blindness among working-age patients, and it has a prevalence of 34.6% among diabetics worldwide. The objectives of this review were to examine the prevalence of DR in Saudi Arabia, describe the major associated risk factors, and raise awareness about the disease among diabetics. The prevalence of DR in Saudi Arabia has risen substantially in recent decades. Significant risk factors associated with DR include older age, longer duration of diabetes, poor glycemic control, and hypertension. Awareness and education about diabetes are associated with better outcomes and fewer complications.
- ArticleToledano Furman N, Gottlieb A, Prabhakara KS, Bedi S, Caplan HW, Ruppert KA, Srivastava AK, Olson SD, Cox CS.Sci Rep. 2020 07 20;10(1):11991.Traumatic brain injury (TBI) results in a cascade of cellular responses, which produce neuroinflammation, partly due to microglial activation. Transforming from surveying to primed phenotypes, microglia undergo considerable molecular changes. However, specific microglial profiles in rat remain elusive due to tedious methodology and limited availability of reagents. Here, we present a flow cytometry-based analysis of rat microglia 24 h after TBI using the controlled cortical impact model, validated with a bioinformatics approach. Isolated microglia are analyzed for morphological changes and their expression of activation markers using flow cytometry, traditional gating-based analysis methods and support the data by employing bioinformatics statistical tools. We use CD45, CD11b/c, and p2y12 receptor to identify microglia and evaluate their activation state using CD32, CD86, RT1B, CD200R, and CD163. The results from logic-gated flow cytometry analysis was validated with bioinformatics-based analysis and machine learning algorithms to detect quantitative changes in morphology and marker expression in microglia due to activation following TBI.
- ArticleHaq A, Modibbo UM, Ahmed A, Ali I.Environ Dev Sustain. 2022;24(10):11991-12018.Since 2015, the United Nations sustainable development goals (SDGs) agenda 2030 has been designed with 17 goals, 169 targets, and 232 unique indicators to help address environmental, development, and sustainability issues globally. India, like other developing nations, desired to achieve its vision 2030 targets. Several authors studied India's SDGs with different approaches. However, none of the studies explores the concept of neutrosophic programming (NP). It is against this drawback; this study presents an optimization model for India's socio-economic and environmental goals based on the NP concept. The NP model is capable of handling indeterminacy in optimization-related problems for which other techniques do not. The formulated models simultaneously optimized the gross domestic product (GDP) growth, electricity consumption, and greenhouse gas (GHG) emissions. The solutions revealed that the degree of satisfaction for the goals related to GDP, electricity consumption, and GHG emissions could be achieved partially. Also, it suggested the required optimal number of employment for each economic sector to achieve India's vision 2030. The SDGs model was further solved with the goal programming (GP) technique and compared with the NP results to validate the proposed concept. It has been found that the proposed model gives a better compromise solution than the GP model. The study can help and guide policymakers in working toward vision 2030 attaintment. Other interested researchers can use the concept in other countries to help decision-makers understand managerial policy implications.
- ArticleWang K, Huang Q, Elshaer MR, Knorr B, Chaikin P, Zhu G.Nanoscale. 2024 Jun 27;16(25):11991-11998.The invention of DNA nanotechnology has enabled molecular computation as a promising substitute for traditional semiconductors which are limited to two-dimensional architectures and by heating problems resulting from densification. Current studies of logic gates achieved using DNA molecules are predominately focused on two-state operations (AND, OR, etc.); however, realizing tri-state logic (high impedance Z) in DNA computation is understudied. Here we actively fold DNA origami chain-like hinged rods to induce conformational changes that return tri-state logic signals. We use rigid six helix-bundle (6HB) DNA origami to self-assemble a linear trimer chain as a circuit platform with functional single-stranded (ss) DNA near each semi-flexible hinge. The presence or absence of ssDNA enable and input strands allows hybridization to take place at the hinges, activating one fold (0) or two folds (1) from the straight linear geometry (defined as High-Z) of the trimer chain. We design two different tri-state logic gate platforms, buffer and inverter, with corresponding enable/input ssDNA to unambiguously return tri-state signals, characterized by Atomic Force Microscopy (AFM) and/or agarose gel electrophoresis (GEL). Our work on tri-state logic significantly enhances DNA computation beyond the current two-state Boolean logic with both research and industrial applications, including cellular treatments and living matter utilizing the biocompatibility of DNA molecules.
- ArticleKo BS, Kim N, Lee JW, Kim HJ, Chung IY, Kim J, Lee SB, Son BH, Kim HH, Seo JB, Kim SB, Gong GY, Kim GB, Lee S, Choi SH, Ahn SH.Sci Rep. 2019 08 19;9(1):11991.Magnetic resonance imaging (MRI) is the most accurate technique for evaluating residual tumor after neoadjuvant chemotherapy. However, precise determination of the extent of dispersed residual tumor in the breast following treatment remains a difficult task. We hereby introduce three-dimensional (3D)-printed surgical guides for use in breast cancer patients undergoing breast-conserving surgery after receiving neoadjuvant chemotherapy. We prospectively applied the 3D-printed surgical guides on breast cancer patients who underwent partial breast resection after receiving neoadjuvant chemotherapy. Breasts and tumors were modeled in 3D by using pretreatment magnetic resonance images, and surgical guides were created by using a 3D printer to mark the primary tumor. Out of the five patients who participated in the study, all patients had clear resection margins, and two patients experienced complete pathological remission. There were no recurrences during the median follow-up period of 21.9 months. Thus, our newly-developed 3D-printed surgical guides were useful for accurately marking the extent of breast tumor based on pretreatment magnetic resonance images, which is important for designating the extent of surgery needed in patients who have received neoadjuvant chemotherapy.
- ArticleOyerokun FT, Vaia RA, Maguire JF, Farmer BL.Langmuir. 2010 Jul 20;26(14):11991-7.We have developed a simple model to quantify the effect of solvent selectivity on the surface composition of two-component self-assembled monolayers formed from solutions containing mixtures of organic thiols. The coarse-grained molecular model incorporates the relevant intermolecular interactions in the solution and monolayer to yield an expression for the free energy of monolayer formation. Minimization of the free energy results in a simple and analytically tractable expression for the monolayer composition as a function of solvent selectivity (defined as the difference in the Flory-type interaction parameters of the two organic thiols in the solution) and the degree of incompatibility between the adsorbate molecules. A comparison of our theory to experiments on the formation of two-component self-assembled monolayers from solution indicates that the coarse-grained molecular model captures the trends in the experimental data quite well.
- ArticleSanzari I, Humphrey EJ, Dinelli F, Terracciano CM, Prodromakis T.Sci Rep. 2018 08 10;8(1):11991.We recently demonstrated that patterned Parylene C films could be effectively used as a mask for directly copolymerizing proteins on polyacrylamide hydrogel (PAm). In this work, we have proved the applicability of this technique for studying the effect such platforms render on neonatal rat ventricular myocytes (NRVMs). Firstly, we have characterised topographically and mechanically the scaffolds in liquid at the nano-scale level. We thus establish that such platforms have physical properties that closely mimics the in vivo extracellular environment of cells. We have then studied the cell morphology and physiology by comparing cultures on flat uniformly-covered and collagen-patterned scaffolds. We show that micro-patterns promote the elongation of cells along the principal axis of the ridges coated with collagen. In several cases, cells also tend to create bridges across the grooves. We have finally studied cell contraction, monitoring Ca2+ cycling at a certain stimulation. Cells seeded on patterned scaffolds present significant responses in comparison to the isotropic ones.
- ArticleKastilan R, Boes A, Spiegel H, Voepel N, Chudobová I, Hellwig S, Buyel JF, Reimann A, Fischer R.Sci Rep. 2017 09 20;7(1):11991.Pichia pastoris is a simple and powerful expression platform that has the ability to produce a wide variety of recombinant proteins, ranging from simple peptides to complex membrane proteins. A well-established fermentation strategy is available comprising three main phases: a batch phase, followed by a glycerol fed-batch phase that increases cell density, and finally an induction phase for product expression using methanol as the inducer. We previously used this three-phase strategy at the 15-L scale to express three different AMA1-DiCo-based malaria vaccine candidates to develop a vaccine cocktail. For two candidates, we switched to a two-phase strategy lacking the intermediate glycerol fed-batch phase. The new strategy not only provided a more convenient process flow but also achieved 1.5-fold and 2.5-fold higher space-time yields for the two candidates, respectively, and simultaneously reduced the final cell mass by a factor of 1.3, thus simplifying solid-liquid separation. This strategy also reduced the quantity of host cell proteins that remained to be separated from the two vaccine candidates (by 34% and 13%, respectively), thus reducing the effort required in the subsequent purification steps. Taken together, our new fermentation strategy increased the overall fermentation performance for the production of two different AMA1-DiCo-based vaccine candidates.