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Order Patatavirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Cuenca et al. (2016) used the TuMV virions as scaffolds for chemical coupling. The lipase B of Candida antarctica was conjugated onto amino groups of the external viral surface by glutaraldehyde as a conjugating agent. The appropriate TuMV nanonets were formed, with large enzyme aggregates deposited. The enzyme remained active in the nanoimmobilized form, even gaining an increased relative specific activity, as compared to the nonimmobilized form. Yuste-Calvo et al. (2019a) elaborated the general strategy of the TuMV chemical modification and evaluated the capacity to conjugate different molecules to the active natural residues, obtaining the multiderivatized VLPs by combination with the genetic fusions. This approach is illustrated in Figure 29.7. The modification strategy was based on the recent 3D structure obtained by electron cryomicroscopy for both the TuMV virions and VLPs to final resolutions 5 and 8 Å, respectively (Cuesta et al. 2019). In contrast to the previously described situation in PVY, the TuMV VLPs produced in N. benthamiana plants conserved the helical architecture of the virion. However, the absence of the single-stranded RNA precluded the interaction between coat subunits mediated by the N-terminal arm (Cuesta et al. 2019).
Synthetic biodegradable polyesters for implantable controlled-release devices
Published in Expert Opinion on Drug Delivery, 2022
Jinal U. Pothupitiya, Christy Zheng, W. Mark Saltzman
Poly(ω-pentadecalactone) (PPDL) is synthesized from the macrocyclic lactone (macrolactone) pentadecalactone [166]. An aliphatic polyester with high crystallinity due to its many methylene units, PPDL resembles low-density polyethylene in its mechanical properties, including tensile strength and ductility. PPDL has a Tm of approximately 100°C and a Tg of −27°C [167]. The synthesis of PPDL can be achieved in two ways: enzymatic ROP catalyzed by lipase from Candida antarctica or chemically catalyzed ROP. Interest for using PPDL for implant fabrication is mainly due to the presence of the ester bonds in its polymer backbone, a critical feature that drives biodegradation. PDL and many of its copolymers have proven to be nontoxic, generating interest in this material in biomedical applications [33,166]. For instance, the copolymer poly(ω-pentadecalactone-co-dioxanone) appears to be an excellent candidate for the use as a matrix for drug-loaded implants [168]. Poly(ω-pentadecalactone) degrades extremely slowly; one study showed no degradation after 2 years of incubation in PBS buffer [166]. This slow degradation can be mitigated by the copolymerization of PDL and DO, making poly(ω-pentadecalactone-co-dioxanone) which yields materials that degrade over a period of months or years [33].
Covalent immobilization of phytase on the multi-walled carbon nanotubes via diimide-activated amidation: structural and stability study
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Mohammad Pooya Naghshbandi, Hamid Moghimi, Babak Latif
In 2008, Schultz et al. stated that there is a clear correlation between zeta potential and loading efficiency of the enzyme through the immobilization process. They also argued that zeta potential could be used as a diagnostic tool in enzyme immobilization [25]. Their reported zeta potential values are −8.2, −11.4 and −9.5 for free Candida antarctica A-type lipase (CALA), non-porous magnetic microparticles with epoxy (M-PVA E02) and nano-immobilized CALA, respectively. The zeta potential values measured in the present study were −13.6, −7.6 and −12.2 for free phytase, functionalized MWNTs, and immobilized phytase, respectively. Accordingly, the proximity of the zeta potential values of free and immobilized phytase could be an indication of successful immobilization of the phytase enzyme over MWNTs. Furthermore, due to the fact that both the enzyme and the nanosupport were negatively charged, physical adsorption would not be an appropriate method for phytase immobilization over MWNTs and that the choice of covalent immobilization was accurate. Nevertheless, this repulsive force could have still impacted on the orientation of the immobilized enzyme on MWNTs and subsequently, could have played a role in decreasing the enzyme activity.
Microencapsulation of esterified krill oil, using complex coacervation
Published in Journal of Microencapsulation, 2018
Selim Kermasha, Sarya Aziz, Jagpreet Gill, Ronald Neufeld
Beef-hide gelatine (GE) Kosher-certified (Type B, 250 ± 10 Bloom, 12.0% moisture, 5 ± 0.42 isoelectric point (IP) was obtained from Vyse Gelatin Company (Schiller Park, IL). Gum arabic (GA) was purchased from ACP Chemicals Inc. (Montreal, QC). High-Potency KO, extracted from Euphausia superba, was generously obtained from Enzymotec Ltd (Morristown, NJ). Commercial immobilised lipase, Novozym 435, from Candida antarctica with an activity of 10 000 propyl laurate units per g solid enzyme, was purchased from Novozymes A/S (Bagsvaerd, Denmark). Barium chloride dehydrate and 3,4-dihydroxyphenylacetic acid (DHPA) were purchased from Sigma Chemical Co. (St-Louis, MO). Ammonium hydroxide, sodium hydroxide, ethanol, glacial acetic acid, hydrochloric acid, p-anisidine (99%), ferrous sulphate, ammonium thiocyanate, organic solvents of high-performance liquid chromatography (HPLC) grade and a standard solution of Fe (III) of 1000 ppm Fe in 3% HCl were purchased from Fisher Scientific (Fair Lawn, NJ).