Stabilization of emulsions prepared by ball milling and cellulase treated pomelo peel insoluble dietary fiber: Integrity of porous fiber structure dominates the stability.

Emulsion gels from the pomelo peel insoluble dietary fiber (PIDF) were developed. The emulsification potentials of PIDFs subjected to various degrees of ball milling (M-PIDFs), cellulase hydrolysis (C-PIDF), and cellulase hydrolysis followed by ball milling (CM-PIDFs) were evaluated. Emulsions prepared by M-PIDFs for different lengths of ball milling time exhibited similar stability characteristics, confirming that M-PIDF emulsion stability might be determined by the three-dimensional structure formed by M-PIDF stacking and oil droplet capture. C-PIDF had characteristics resembling those of Pickering particles. CM-PIDF emulsions got destabilized with ball milling time prolongation. Interface tension and particle size of C/CM-PIDF decreased gradually during ball milling. Rheological and fluorescence microscopy results revealed that the intact internal crosslinking structure frameworks were disrupted in CM-PIDF emulsions. Therefore, intact fiber-based networks, rather than small particle size or low interfacial tension, determine the stability of PIDF emulsions. This study deepens the understanding of PIDF as a clean emulsifier.

Wheat heat shock factor TaHsfA2d contributes to plant responses to phosphate deficiency.

Phosphate (Pi) availability has become a major constraint limiting crop growth and production. Heat shock factors (Hsfs) play important roles in mediating plant resistance to various environmental stresses, including heat, drought and salinity. However, whether members of the Hsf family are involved in the transcriptional regulation of plant responses to Pi insufficiency has not been reported. Here, we identified that TaHsfA2d, a member of the heat shock factor family, was strongly repressed by Pi deficiency. Overexpressing TaHsfA2d-4A in Arabidopsis results in significantly enhanced sensitivity to Pi deficiency, evidenced by increased anthocyanin content, decreased proliferation and elongation of lateral roots, and reduced Pi uptake. Furthermore, RNA-seq analyses showed that TaHsfA2d-4A functions through up-regulation of a number of genes involved in stress responses and flavonoid biosynthesis. Collectively, these results provide evidence that TaHsfA2d participates in the regulation of Pi deficiency stress, and that TaHsfA2d could serve as a valuable gene for genetic modification of crop tolerance to Pi starvation.

Feasibility of pomelo peel dietary fiber as natural functional emulsifier for preparation of Pickering-type emulsion.

BACKGROUND: The application of Pickering emulsions stabilized by food-derived particles is of great interest, studies have focused on development of natural functional emulsifiers from agricultural byproducts. Dietary fiber (DF) has been recognizing for its excellent physiological functions. Moreover, physicochemical properties of pomelo peel DF (PDF) make it a potential emulsifier. However, pristine PDF is not suitable as emulsifier due to its compact physical structure and high hydrophobicity, which seriously limits its utilization. The objective of the study was to investigate the effects of cellulase on physicochemical properties of PDF and to illustrate the feasibility of cellulase modified PDF (MPDF) as natural functional emulsifier. RESULTS: Cellulase modification significantly improved (P < 0.05) specific surface area, water-holding capacity/oil-holding capacity, viscoelasticity, hydrophobicity, and pore structure while decreased crystallinity index and particle size of PDF. Emulsion could remain stable over 30 days as MPDF concentrations up to 1 wt% and oil/water ratio 3:7. The appearance stability of emulsions was not influenced by temperature (4-60 °C), pH (3.0-12.0), and ion concentration (0-200 mmol L-1 ) which was similar to Pickering emulsions. The mechanism of MPDF as an emulsifier was mainly attributed to the combination of Pickering effect and the three-dimensional network. In addition, MPDF showed higher antioxidant capacity in emulsions than other classical emulsifiers. CONCLUSION: The results illustrated that MPDF has a favorable feasibility for preparation of stable Pickering-type emulsions, which will be a practical support for application of PDF as a natural functional emulsifier and will be helpful to realize the resource utilization of DF in pomelo industries. © 2022 Society of Chemical Industry.

General Control Non-derepressible 1 (AtGCN1) Is Important for Flowering Time, Plant Growth, Seed Development, and the Transcription/Translation of Specific Genes in Arabidopsis.

We have previously demonstrated that General Control Non-derepressible 1 (AtGCN1) is essential for translation inhibition under cold stress through interacting with GCN2 to phosphorylate eukaryotic translation initiation factor 2 (eIF2). Here, we report that the flower time of the atgcn1 mutant is later than that of the wild type (WT), and some siliques of atgcn1 cannot develop and produce seeds. Total and polysomal RNA of atgcn1-1 and wild type (WT) after cold treatments were sequenced. The sequencing results show that the mutation of atgcn1 selectively alters the expression of genes at both transcriptional and translational levels. The classification of AtGCN1 target genes reveals that AtGCN1 regulated gens are involved in flower development, seed dormancy and seed development, response to osmotic stress, amino acid biosynthesis, photosynthesis, cell wall organization, protein transport and localization, lipid biosynthesis, transcription, macroautophagy, proteolysis and cell death. Further analysis of AtGCN1 regulated genes at translational levels shows that the Kozak sequence and uORFs (upstream open reading frame) of transcripts affect translation selection. These results show that AtGCN1 is required for the expression of selective genes in Arabidopsis.

Heterotrophic cultivation of Chlorella vulgaris using broken rice hydrolysate as carbon source for biomass and pigment production.

The high cost of carbon source limits the heterotrophic culture of Chlorella. In this study, broken rice was hydrolyzed into glucose. Then, the broken rice hydrolysate (BRH) was utilized for heterotrophic cultivation of C. vulgaris instead of glucose. Results showed that algal cells released H+ when they consumed NH4+, leading to a sharp decrease in pH. Growth inhibition by acid could be avoided by using a pH buffer. Adding alkaline reagents intermittently during culture could not only reduce the amount of pH stabilizer but also obtain increased biomass production. When using Tris as pH stabilizer, the biomass productivity of C. vulgaris in BRH was the largest (1.01 g/L/d), followed by NaOH (1.00 g/L/d), and Na2CO3 (0.95 g/L/d). Using BRH instead of glucose for heterotrophic cultivation of C. vulgaris could save 89.58% of the cost of culture medium. This study developed a novel strategy for cultivating C. vulgaris heterotrophically using BRH.

TMSCFX2 (X = Cl, Br) as halofluorocarbene sources for the synthesis of halofluorocyclopropanes.

TMSCFX2 (X = Cl, Br; TMS = trimethylsilyl) have been developed as halofluorocarbene (CFX, X = Cl, Br) precursors for [2+1] cyclopropanation with alkenes. Structurally diverse halofluorocyclopropanes were obtained in good to excellent yields. It was found that the reactivity order of the three halofluorocarbene reagents (TMSCF2Br, TMSCFCl2, and TMSCFBr2) in halofluorocyclopropanation with 1,1-diphenylethylene can be very different under different reaction conditions.

Fish Collagen Surgical Compress Repairing Characteristics on Wound Healing Process In Vivo.

The development of biomaterials with the potential to accelerate wound healing is a great challenge in biomedicine. In this study, four types of samples including pepsin soluble collagen sponge (PCS), acid soluble collagen sponge (ACS), bovine collagen electrospun I (BCE I) and bovine collagen electrospun II (BCE II) were used as wound dressing materials. We showed that the PCS, ACS, BCE I and BCE II treated rats increased the percentage of wound contraction, reduced the inflammatory infiltration, and accelerated the epithelization and healing. PCS, ACS, BCE I, and BCE II significantly enhanced the total protein and hydroxyproline level in rats. ACS could induce more fibroblasts proliferation and differentiation than PCS, however, both PCS and ACS had a lower effect than BCE I and BCE II. PCS, ACS, BCE I, and BCE II could regulate deposition of collagen, which led to excellent alignment in the wound healing process. There were similar effects on inducing the level of cytokines including EGF, FGF, and vascular endothelial marker CD31 among these four groups. Accordingly, this study disclosed that collagens (PCS and ACS) from tilapia skin and bovine collagen electrospun (BCE I and BCE II) have significant bioactivity and could accelerate wound healing rapidly and effectively in rat model.

The spectroscopy analyses of PpIX by ultrasound irradiation and its sonotoxicity in vitro.

Protoporphyrin IX (PpIX) has been used as a sensitizer in photodynamic therapy (PDT) as well as in sonodynamic therapy (SDT). The photo-bleaching of PpIX has been well investigated in many experimental systems and some photo-products have also been identified in PDT. But until now, little information has been reported about the sono-damage of PpIX in SDT. So, the present study was to investigate changes of PpIX properties before and after different ultrasound treatment, and the potential interactions between PpIX, ultrasound and the irradiated cells. In cell-free system, the absorption and fluorescence spectra of PpIX in different solutions were measured by ultraviolet spectrometer and fluorescence spectrophotometer, respectively. The terephthalic acid dosimetry was applied to evaluate the efficiency of ultrasound cavitation by monitoring hydroxyl radical (OH) production on the thermolysis of H2O in the ultrasound field. In in vitro study, confocal microscopy was applied to detect the sub-cellular localization of PpIX in S180 cells before and after ultrasound exposure. Flow cytometry was used to detect the reactive oxygen species (ROS) generation during PpIX-SDT. MTT assay was performed to evaluate the cell viability of S180 cells after SDT treatment with or without ROS scavengers. The results show that PpIX displayed different spectral patterns in different solutions. PpIX was decomposed by ultrasound exposure as measured by the decreased absorption and fluorescence peak values in RPMI-1640 medium. In addition, the decomposition of PpIX was found to be simultaneously accompanied by OH production with increasing output power from ultrasound generator. PpIX at 1µg/ml significantly enhanced the ultrasound induced cavitation as measured by OH generation, and which was greatly eliminated by NaN3, histidine, mannitol, EDTA and catalase, but not by SOD. The in vitro study indicates more PpIX entered into S180 cells after ultrasound exposure. And, the extra-cellular PpIX play an important role in the enhanced cell killing of PpIX-SDT. SDT induced obvious ROS generation in S180 cells, which could be mostly inhibited by the general ROS scavenge NAC (N-acetylcysteine). Other scavengers such as NaN3, histidine, mannitol all partially prevented the SDT induced cell viability loss of S180 cells, suggesting OH, (1)O2 might be involved during the process.