Molecular mechanisms underlying the vulnerability of Pacific abalone (Haliotis discus hannai) to Vibrio harveyi infection at higher water temperature.

Climate change is one of the most important threats to farmed abalone worldwide. Although abalone is more susceptible to vibriosis at higher water temperatures, the molecular mode of action underlying this has not been fully elucidated. Therefore, this study aimed to address the high susceptibility of Halitotis discus hannai to V. harveyi infection using abalone hemocytes exposed to low and high temperatures. Abalone hemocytes were divided into four groups, 20C, 20 V, 25C, and 25 V, depending on co-culture with (V)/without (C) V. harveyi (MOI = 12.8) and incubation temperature (20 °C or 25 °C). After 3 h of incubation, hemocyte viability and phagocytic activity were measured, and RNA sequencing was performed using Illumina Novaseq. The expression of several virulence-related genes in V. harveyi was analyzed using real-time PCR. The viability of hemocytes was significantly decreased in the 25 V group compared to cells in the other groups, whereas phagocytic activity at 25 °C was significantly higher than at 20 °C. Although a number of immune-associated genes were commonly upregulated in abalone hemocyte exposed to V. harveyi, regardless of temperature, pathways and genes regarding pro-inflammatory responses (interleukin-17 and tumor necrosis factor) and apoptosis were significantly overexpressed in the 25 V group compared to the 25C group. Notably, in the apoptosis pathway, genes encoding executor caspases (casp3 and casp7) and pro-apoptotic factor, bax were significantly up-regulated only in the 25 V group, while the apoptosis inhibitor, bcl2L1 was significantly up-regulated only in the 20 V group compared to the control group at the respective temperatures. The co-culture of V. harveyi with abalone hemocytes at 25 °C up-regulated several virulence-related genes involved in quorum sensing (luxS), antioxidant activity (katA, katB, and sodC), motility (flgI), and adherence/invasion (ompU) compared to those at 20 °C. Therefore, our results showed that H. discus hannai hemocytes exposed to V. harveyi at 25 °C were highly stressed by vigorously activated inflammatory responses and that the bacterial pathogen overexpressed several virulence-related genes at the high temperature tested. The transcriptomic profile of both abalone hemocytes and V. harveyi in the present study provide insight into differential host-pathogen interactions depending on the temperature conditions and the molecular backgrounds related to increased abalone vulnerability upon global warming.

Development of soy protein isolate/sodium carboxymethyl cellulose synbiotic microgels by double crosslinking with transglutaminase and aluminum chloride for delivery system of Lactobacillus acidophilus.

This study was carried out to develop soy protein isolate (SPI)/sodium carboxymethyl cellulose (NaCMC) synbiotic microgels by applying a double-crosslinking technique using transglutaminase and different concentrations of AlCl3 (0 %, 6 %, 7 %, 8 %) and also by adding Lactobacillus acidophilus (L. acidophilus) and pectic oligosaccharide. Synbiotic microgels crosslinked using 8 % AlCl3 (SPI/NaCMC-Al3+8 microgels) showed the highest encapsulation efficiency (92 %). The double-crosslinked microgels exhibited a smooth surface as proved by SEM. FT-IR, XRD, and DSC analyses showed the possible interaction within matrices and demonstrated the higher thermal stability of synbiotic microgels prepared using a higher concentration of AlCl3. All in all, after exposure to simulated digestion fluid, heat treatment (72 °C, 15 s), and refrigerated storage, more cells in double-crosslinked microgels survived compared to single-crosslinked microgels. In particular, probiotic viability was highest in SPI/NaCMC-Al3+8 microgels. These results indicate that the SPI/NaCMC-Al3+8 microgels developed in this study can effectively protect L. acidophilus against the external environment.

Synthesis, characterization, and functional properties of chlorophylls, pheophytins, and Zn-pheophytins.

The aims of this study were to synthesize chlorophyll derivatives, pheophytins and Zn-pheophytins, from chlorophylls extracted from spinach, characterize them, and evaluate their antioxidant and anti-inflammatory activities. The chlorophylls isolated from spinach were identified by means of FT-IR and NMR spectroscopies. The synthesis of pheophytins and Zn-pheophytins was confirmed by UV-Vis spectral analyses. The antioxidant activity of chlorophylls, pheophytins, and Zn-pheophytins was studied. The results revealed that the Zn-pheophytins showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ß-carotene bleaching activities, followed by chlorophylls and pheophytins. Additionally, Zn-pheophytins showed substantial inhibitory activity against lipopolysaccharide (LPS)-induced NO production in RAW 264.7 cells. Furthermore, Zn-pheophytins remarkably suppressed LPS-induced expression of inducible nitric oxide synthase (iNOS) in RAW 264.7 cells and showed no cytotoxicity. Our findings indicated that Zn-pheophytins have strong antioxidant and anti-inflammatory properties and can therefore be a potential source of bioactive compounds for nutraceutical, cosmetic, and pharmaceutical applications.