Isolation of Sulfated Anticoagulant Compound from Fermented Red Seaweed Grateloupia filicina

The red alga Grateloupia filicina was fermented with 0.15 g/mL sucrose at 25 C, and anticoagulant activity was measured biweekly up to the 10th wk by activated partial thromboplastin time (APTT). A sulfated polysaccharide compound having anticoagulant activity was purified from the sixth wk of fermentation by fast protein liquid chromatography using diethylaminoethyl cellulose followed by a sepharose‐4B column. The concentration of the purified sulfated anticoagulant polysaccharide was 136.65 μg/mL, and the sulfate concentration of the purified compound was 26.33 μg/mL. The presence of just a single spot on agarose gel electrophoresis confirmed that the compound was purified, and polyacrylamide gel electrophoresis showed that the purified compound was of high molecular mass. The purified sulfated anticoagulant polysaccharide consisted of galactose, glucose, and mannose in an approximate molar ratio of 0.95 : 0.01 : 0.03. Both purified anticoagulant and commercial heparin showed >1000 sec APTT activity at 136.65 μg/mL. As the technique of fermentation is inexpensive, the purified anticoagulant compound could have significant potential in the medical and pharmaceutical industry.     

Spirulina maxima Derived Pectin Nanoparticles Enhance the Immunomodulation,Stress Tolerance,and Wound Healing in Zebrafish

In this study, Spirulina maxima derived pectin nanoparticles (SmPNPs) were synthesized and multiple biological effects were investigated using in vitro and in vivo models. SmPNPs were not toxic to Raw 264.7 cells and zebrafish embryos up to 1 mg/mL and 200 µg/mL, respectively. SmPNPs upregulated Il 10, Cat, Sod 2, Def 1, Def 2, and Muc 1 in Raw 264.7 cells and tlr2, tlr4b, tlr5b, il1β, tnfα, cxcl8a, cxcl18b, ccl34a.4, ccl34b.4, muc5.1, muc5.2, muc5.3, hamp, cstd, hsp70, cat, and sod1 in the larvae and adult zebrafish, suggesting immunomodulatory activity. Exposure of larvae to SmPNPs followed by challenge with pathogenic bacterium Aeromonas hydrophila resulted a two-fold reduction of reactive oxygen species, indicating reduced oxidative stress compared to that in the control group. The cumulative percent survival of larvae exposed to SmPNPs (50 µg/mL) and adults fed diet supplemented with SmPNPs (4%) was 53.3% and 76.7%, respectively. Topical application of SmPNPs on adult zebrafish showed a higher wound healing percentage (48.9%) compared to that in the vehicle treated group (38.8%). Upregulated wound healing markers (tgfβ1, timp2b, mmp9, tnfα, il1β, ccl34a.4, and ccl34b.4), enhanced wound closure, and restored pigmentation indicated wound healing properties of SmPNPs. Overall, results uncover the multiple bioactivities of SmPNPs, which could be a promising biocompatible candidate for broad range of aquatic and human therapies.     

Modified atmosphere packaging of minimally processed avocado cv. ‘Booth 7’

Summary

Avocado fruits were washed with 200 µg l^–1 active chlorine, partially ripened to a firmness of about 12.5 ± 0.6 kg cm^–2, and sliced. Fruit slices were dipped in 1.0 mg l^–1 citric acid and 200 µg l^–1 ascorbic acid maintained at 4°–6°C for 2 min, dried with tissue paper and packaged in 0.05 mm or 0.075 mm-thick low density polyethylene (LDPE) at a 1:1 surface area to product weight ratio (cm² g^–1). Sodium chloride (1 g) sealed in 0.075 mm-thick poly-coated paper pouches was included in the packages for moisture absorption. In-package O₂ and CO₂ concentrations, as well as the ethanol and acetaldehyde concentrations, firmness and lightness (L^* value) of the tissue slices were measured during storage for 10 d. The sensory attributes of the modified atmosphere (MA)-packaged slices were compared with fresh fruit slices. In-package O₂ concentrations fell from 14.1% to 6.3% and CO₂ concentrations rose from 4.7% to 4.9%. Ethanol concentrations increased from 9.0 to 32.1 µg g^–1 and acetaldehyde from 1.1 to 3.8 µg g^–1 during storage from day-1 to day-10 in the 0.05 mm-thick LDPE with sodium chloride moisture absorbers. In-package concentrations of O₂ fell from 10.8% to 3.8% and CO₂ rose from 3.8% to 8.1%, while ethanol concentrations increased from 10.0 to 40.4 µg g^–1 and acetaldehyde from 1.3 to 4.7 µg g^–1 during storage from day-1 to day-10 in the 0.075 mm-thick LDPE with sodium chloride moisture absorbers. The L^* value and sensory attributes of avocado slices packaged in 0.05 mm-thick LDPE, with moisture absorbers, were not significantly different from fresh slices, indicating the effectiveness of these MA conditions. Regardless of packaging conditions, avocado slices reached the firmness values of 5.8–6.3 kg cm^–2 required for the ‘table-ripe’ stage on day-10 in storage. Therefore, packaging of ‘Booth 7’ avocado slices in 0.05 mm-thick LDPE with sodium chloride as a moisture absorber resulted in a storage-life of 10 d at 8°C and 90 ± 2% RH.     

Effects of water temperature on mortality in Megalocytivirus‐infected rock bream Oplegnathus fasciatus (Temminck et Schlegel) and development of protective immunity

Rock bream iridovirus (RBIV) causes huge losses, especially in rock bream Oplegnathus fasciatus. Rock bream injected with RBIV and held at 29, 26, 23 or 20 °C had 100% mortality. Conversely, all infected fish held at 17 °C survived even after the temperature was progressively increased to 26 °C at 100 dpi. Rock bream exposed to virus and held for 2, 4 and 7 days at 23/26 °C before the temperature was reduced to 17 °C had mortality rates of 26.6/73.2%, 66.6/100% and 93.4/100%, respectively, through 100 dpi. When surviving fish had the water temperature increased from 17 to 26 °C at 100 dpi, they did not exhibit signs of disease and had low virus copy numbers (below 10³). To investigate the development of a protective immune, rock bream were infected with RBIV and held at 23 °C before shifting the water temperature to 17 °C at 4 dpi. All injected fish survived until 120 dpi. While 100% of the previously unexposed fish died, 80.2% of the previously infected fish survived. When the survivors were rechallenged again at 160 dpi, no further mortality occurred. The high survival rate of fish following rechallenge with RBIV indicates that protective immunity was established in the surviving rock bream.     

A Novel Pseudoalteromonas xiamenensis Marine Isolate as a Potential Probiotic: Anti-Inflammatory and Innate Immune Modulatory Effects against Thermal and Pathogenic Stresses

A marine bacterial strain was isolated from seawater and characterized for it beneficial probiotic effects using zebrafish as a model system. The strain was identified by morphological, physiological, biochemical, and phylogenetic analyses. The strain was most closely related to Pseudoalteromonas xiamenensis Y2, with 99.66% similarity; thus, we named it Pseudoalteromonas xiamenensis S1131. Improvement of host disease tolerance for the P. xiamenensis isolate was adapted in a zebrafish model using Edwardsiella piscicida challenge. The larvae were pre-exposed to P. xiamenensis prior to E. piscicida challenge, resulting in a 73.3% survival rate compared to a 46.6% survival for the control. The treated larvae tolerated elevated temperatures at 38 °C, with 85% survival, compared to 60% survival for the control. Assessment of immunomodulatory responses at the mRNA level demonstrated the suppression of pro-inflammatory markers tnfα and il6, and upregulation of heat shock protein hsp90 and mucin genes. The same effect was corroborated by immunoblot analysis, revealing significant inhibition of Tnfα and an enhanced expression of the Hsp90 protein. The antibacterial activity of P. xiamenensis may be related to mucin overexpression, which can suppress bacterial biofilm formation and enhance macrophage uptake. This phenomenon was evaluated using nonstimulated macrophage RAW264.7 cells. Further studies may be warranted to elucidate a complete profile of the probiotic effects, to expand the potential applications of the present P. xiamenensis isolate.