Reevaluating the splice-altering variant in TECTA as a cause of nonsyndromic hearing loss DFNA8/12 by functional analysis of RNA.

PURPOSE: The aim of this study was to determine the genetic cause of early onset autosomal dominant hearing loss segregating in five-generation kindred of Chinese descent and provide preimplantation genetic testing (PGT)for them. METHODS: Clinical examination, pedigree analysis and exome sequencing were carried out on the family. Minigene-based splicing analysis, in vivo RNA analysis and protein structure prediction by molecular modeling were conducted on the candidate variant. PGT for the causative variation and chromosome aneuploidis based on SNP analysis has been used for avoidance of hearing loss in this family. RESULTS: All the affected individuals presented with moderate down-sloping hearing loss and whole-exome sequencing identified a novel splice-site variant c.5383+6T>A in the tested subjects within the TECTA locus. Genotyping of all the 32 family members confirmed segregation of this variant and the hearing loss phenotype in the extended family. Functional analysis of RNA and molecular modeling indicates that c.5383+6T>A is a pathogenic splice-site variant and should be considered as genetic cause of the hearing loss. Furthermore, a successful singleton pregnancy with no variation in TECTA c.5383+6 was established and a healthy male child was born by PGT. CONCLUSION: We have identified a novel variant c.5383+6T>A in TECTA ZA-ZP inter-domain, which could be attributable to the early-onset autosomal dominant hearing loss. The implications of our study are valuable in elucidating the disrupted RNA splicing and uncovering the genetic cause of hearing loss with TECTA pathogenic variants, as well as providing reproductive approaches to healthy offspring.

Emulsions stabilized by cellulose-based nanoparticles for curcumin encapsulations: In vitro antioxidant properties.

To improve the dispersity and antioxidant properties of curcumin, curcumin emulsions covered with cellulose particles (CP) with different structures were successfully prepared, and the structural characteristics, stability, and antioxidant properties of emulsions were investigated. The results showed that the CP obtained by increasing the hydrolysis time had smaller particle size, better water dispersion, and interfacial adsorption capacity. The encapsulation efficiency of curcumin in emulsion stabilized by cellulose particle hydrolyzed for 10 h can reach about 80%. After 9 days, all emulsions showed good stability, and no obvious creamed layer was observed. Compared to cellulose particles hydrolyzed for 2 h (CP2), emulsions stabilized by cellulose particles hydrolyzed for 6 h (CP6) and 10 h (CP10) exhibited better stability and free fatty acid (FFA) release. Meanwhile, the DPPH scavenging activity of curcumin emulsion stabilized by CP significantly increased with increasing the hydrolysis time and was much higher than that of pure emulsion and curcumin/water due to the higher solubility (1,455 times compared with curcumin/water solution) of curcumin, and these results could provide useful data for the stability and encapsulation of curcumin.

A study of Pb2+ induced unfolding and aggregation of arginine kinase from Euphausia superba: kinetics and computational simulation integrating study.

Arginine kinase is a crucial phosphagen kinase in invertebrates, which is associated to the environmental stress response, plays a key role in cellular energy metabolism. In this study, we investigated the Pb2+-induced inhibition and aggregation of Euphausia superba arginine kinase (ESAK) and found that significantly inactivated ESAK in a dose-dependent manner (IC50 = 0.058 ± 0.002 mM). Spectrofluorimetry results showed that Pb2+ induced tertiary structural changes via the internal polarity increased and the non-polarity decreased in ESAK and directly induced ESAK aggregation. The ESAK aggregation process induced by Pb2+ occurred with multi-phase kinetics. The addition of osmolytes did not show protective effect on Pb2+-induced inactivation of ESAK. The computational molecular dynamics (MD) simulation showed that three Pb2+ interrupt the entrance of the active site of ESAK and it could be the reason on the loss of activity of ESAK. Several important residues of ESAK were detected that were importantly contributed the conformation and catalytic function of ESAK. Our study showed that Pb2+-induced misfolding of ESAK and the complete loss of activity irreversibly, which cannot be recovered by osmolytes.Communicated by Ramaswamy H. Sarma.

Sepiolite-zeolite powder doped with capric acid phase change microcapsules for temperature-humidity control.

A composite material with temperature-humidity control functions was prepared by using sepiolite-zeolite powder as humidity control matrix and capric acid phase change microcapsules as temperature control material. The micromorphology, thermal conductivity, compressive strength, hygrothermal effect were studied by environmental scanning electron microscope (ESEM), thermal conductivity test, strength test and hygrothermal effect test, respectively. The results showed that the phase change temperature of capric acid phase change microcapsule is between 31 °C ~ 32 °C, the phase change enthalpy is 123.91 J/g, and it has good thermal stability. The humidity control performance is the best and the maximum humidity absorption rate is 6.28% when sepiolite-zeolite powder ratio is 9:1. The humidity control matrix@CAM (Capric acid microcapsules) can control the relative humidity of the environment at 51.74 ~ 58.54% and reduce the temperature fluctuation range by 2 °C ~ 3 °C. Capric acid phase change microcapsules are embedded in the interlaced sepiolite and zeolite powder to form a frame space body which produce capillary condensation adsorption and surface adsorption, absorb and desorb heat through phase changes, thus giving humidity control matrix@CAM a good temperature-humidity control performance.

Highly efficient photothermal conversion capric acid phase change microcapsule: Silicon carbide modified melamine urea formaldehyde.

The microcapsule containing phase change materials(microPCMs) with high efficiency of photothermal conversion was prepared by in-situ polymerization via ultrasonic dispersion which used capric acid(CA) as core material and nano silicon carbide(nano-SiC) modified melamine-urea-formaldehyde(MUF) resin as wall material. The nano-SiC has good cross-linking with MUF shell. When the nano-SiC was added in microPCMs, it behaves superior thermal conductivity and thermal storage properties. When the content of nano-SiC arrives 6 wt%, the performance of the microPCMs whose encapsulation efficiency is 65.7% is the best, and thermal conductivity increase by 59.2%. Due to the proper amount of nano-SiC added into the MUF shell, it can effectively fill the tiny holes on the MUF shell. Therefore, the microPCMs with appropriate nano-SiC have better leakage prevention. It is worth noting that MicroPCMs-6% and MicroPCMs-8% show excellent photothermal conversion property, and the photothermal conversion rate is 74.4% and 71.1% respectively in the photothermal conversion experiment. Because nano-SiC can effectively capture and absorb photons under light irradiation and convert light into heat through internal molecular vibration, the microPCMs with appropriate nano-SiC behaves well in photothermal conversion. In other words, microPCMs have potential in solar energy utilization and thermal energy storage.

Nutrient and ruminal fermentation profiles of Camellia seed residues with fungal pretreatment.

OBJECTIVE: The experiment was conducted to evaluate the effects of four fungal pretreatments on the nutritional value of Camellia seed residues, and to evaluate the feeding value of pre-treated Camellia seed residues for ruminants. METHODS: Camellia seed residues were firstly fermented by four lignin degrading fungi, namely, Phanerochaete chrysosporium (P. chrysosporium)-30942, Trichoderma koningiopsis (T. koningiopsis)-2660, Trichoderma aspellum (T. aspellum)-2527, or T. aspellum-2627, under solid-state fermentation (SSF) conditions at six different incubation times. The nutritional value of each fermented Camellia seed residues was then analyzed. The fermentation profiles, organic matter degradability and metabolizable energy of each pre-treated Camellia seed residue were further evaluated using an in vitro rumen fermentation system. RESULTS: After 5 days of fermentation, P. chrysosporium-30942 had higher degradation of lignin (20.51%), consumed less hemicellulose (4.02%), and the SSF efficiency reached 83.43%. T. koningiopsis-2660 degraded more lignin (21.54%) and consumed less cellulose (20.94%) and hemicellulose (2.51%), the SSF efficiency reached 127.93%. The maximum SSF efficiency was 58.18% for T. aspellum-2527 and 47.61% for T. aspellum-2627, appeared at 30 and 15 days respectively. All the fungal pretreatments significantly improved the crude protein content (p<0.05). The Camellia seed residues pretreated for 5 days were found to possess significantly increased organic matter degradability, volatile fatty acid production and metabolizable energy (p<0.05) after the treatment of either P. chrysosporium-30942, T. koningiopsis-2660 or T. aspellum-2527. The fungal pretreatments did not significantly change the rumen fermentation pattern of Camellia seed residues, with an unchanged ratio of acetate to propionate. CONCLUSION: The fungi showed excellent potential for the solid-state bioconversion of Camellia seed residues into digestible ruminant energy feed, and their shorter lignin degradation characteristics could reduce loss of the other available carbohydrates during SSF.

SpyTag/SpyCatcher molecular cyclization confers protein stability and resilience to aggregation.

The capacities for thermal and inhibitor tolerance are critical for industrial enzymes and loss of activity is a major challenge in deploying natural enzymes for commercial applications. Protein engineering approaches, such as site-directed mutagenesis and directed evolution, have been devoted to modifying natural enzymes. Recently, a post-translation protein engineering strategy, the SpyTag/SpyCatcher system, was introduced. Here, we have generated a thermo- and ion-tolerant cyclized xylanase (C-TFX) by fusing the SpyTag and SpyCatcher peptides to its N- and C- terminus respectively. Compared with the linear enzyme, C-TFX retained greater residual activity after heating or metal ion exposure. Intrinsic fluorescence and circular dichroism analysis revealed that the isopeptide bond mediated by SpyTag/SpyCatcher cyclization contributed to enhanced thermo- and ion-stability, probably by stabilizing its secondary and conformational structure. In addition, the heat-challenged C-TFX was observed to degrade natural lignocellulosic substrates efficiently. The cyclized xylanase was more stable and resistent to denaturation and aggregation than the linear enzyme. The "superglue" SpyTag/SpyCatcher cyclization system enables the enzyme to maintain its structural conformation, which will be of particular interest in engineering of enzymes for industrial application such as feed additives and functional oligosaccharides production.

Engineering the thermostability of a xylanase from Aspergillus oryzae by an enhancement of the interactions between the N-terminus extension and the ß-sheet A2 of the enzyme.

A mesophilic Aspergillus oryzae xylanase (AoXyn11A) belongs to glycoside hydrolase family 11. Hydrogen bonds and a disulfide bridge were introduced between the N-terminus extension and the ß-sheet A2 of AoXyn11A, which were located in the corresponding region of a hyperthermostable xylanase. The mutants were designated as AoXyn11A(C5) and AoXyn11A(C5-C32), respectively. The thermostabilities of AoXyn11A and the mutants were assessed by the molecular dynamics simulations. After being incubated at 55 °C for 30 min, AoXyn11A(C5-C32) retained 49 % of its original activity, AoXyn11A(C5) retained 12 % and AoXyn11A retained 3 %. The interactions between the N-terminus extension and the ß-sheet A2 were analyzed in depth: there was enhancement of the interactions between the N-terminus extension and the ß-sheet A2 of AoXyn11A that improved its thermostability.