The exogenous autophagy inducement alleviated the sea cucumber (Stichopus japonicus) autolysis with exposure to stress stimuli of ultraviolet light.

BACKGROUND: Autolysis is the most important restrictive factor for the live sea cucumber trade and commercial transportation. Thus, it is essential to investigate the mechanism of autolysis activation or deactivation in the sea cucumber. In this study, monodansylcadaverine staining and Western blotting experiment methods indicated the implication of autophagy in the ultraviolet (UV) exposed sea cucumbers. The health condition was observed after the sea cucumbers (Stichopus japonicus) were gastric perfusion with autophagic inhibitor (3-methyladenine) or inducer (rapamycin) and exposure to UV light for half an hour. RESULTS: The protein expressions of LC3-II and Atg5 appeared immediately after UV exposure and then vanished 1 h later. The autophagosome formation in coelomic fluid cells confirmed the autophagy appearance pattern of LC3-II and Atg5. The sea cucumber individuals maintained the health condition during the entire event of autophagy. The autophagic inhibitor along with UV exposure contributed to sea cucumber's swollen intestinal tissues, but the autophagic inducer functioned to alleviate and neutralize the UV effect. CONCLUSIONS: The autophagy procedure analysis demonstrated that autophagy plays a role to maintain the health condition of sea cucumber during autolysis inducement. The autolysis of sea cucumber can be alleviated or postponed by the exogenous autophagy inducer and this finding would benefit the live sea cucumber transportation. © 2021 Society of Chemical Industry.

Resveratrol Ameliorates Pressure Overload-induced Cardiac Dysfunction and Attenuates Autophagy in Rats.

Pressure overload has an important role in heart failure, inducing excessive autophagy in cardiac myocytes that is considered to be pathogenic. Resveratrol has been reported to improve cardiac dysfunction induced by pressure overload, but it has been unclear whether resveratrol ameliorates cardiac dysfunction by regulating autophagy. In this study, heart failure was induced in rats by constriction of the abdominal aorta. Four weeks after surgery, the rats with heart failure were randomized to treatment with resveratrol (8 mg · kg(-1) · d(-1) by intraperitoneal injection) for 28 days or to intraperitoneal injection of the vehicle (propylene glycol) alone. Echocardiography was performed to assess cardiac function. Expression of brain natriuretic peptide messenger RNA in the left ventricle was detected by real-time polymerase chain reaction, whereas expression of proteins associated with autophagy (beclin-1 and lamp-1) was detected by western blotting and immunohistochemistry. Furthermore, autophagic vacuoles were detected in the heart by transmission electron microscopy, and the myocardial ATP content was measured by the bioluminescence method. Treatment with resveratrol significantly improved cardiac dysfunction and reduced brain natriuretic peptide expression in rats with heart failure. Resveratrol down-regulated beclin-1 and lamp-1 expression and also inhibited the formation of autophagic vacuoles in failing hearts. Furthermore, resveratrol restored the myocardial ATP level and reduced phosphorylation of AMP-activated protein kinase at Thr172. These results suggest that resveratrol may inhibit autophagy through inactivation of AMP-activated protein kinase and restoration of ATP in heart failure induced by pressure overload. Accordingly, resveratrol may be beneficial for patients with hypertensive heart disease.

Preparation of antibacterial composite film based on arginine-modified chitosan and its application in the preservation of ready-to-eat sea cucumber.

An edible composite film was developed and applied for ready-to-eat sea cucumber storage to improve the product quality. The PAC film base is first prepared by mixing 0.5 % glycerin (GL) with 4 % polyvinyl alcohol (PVA) and 1 % arginine-modified chitosan (Arg-CTS) in the same volume. After the addition of nano-ZnO (ZnO) and thymol (Thy) to the PAC film base, the mechanical properties and functions were tested. Compared to the PAC film, the PAC-ZnO-ThyH composite film showed a 1.34-fold increase in the DPPH scavenging rate and a 2.19-fold increase in the ABTS scavenging rate. Contrary to the PAC film, the inhibition zone diameter of Escherichia coli and Staphylococcus aureus significantly increased by 2.35 and 4.08 folds in the PAC-Zno-ThyH film, respectively. After applying the PAC-ZnO-ThyH film to store ready-to-eat sea cucumber for 10 days, there was a significant reduction in weight loss, total volatile basic nitrogen (TVB-N), and lipid oxidation levels to 1.47 and 1.26 folds to the Ctrl group. After preservation, the hardness and chewiness of ready-to-eat sea cucumber were maintained at 1079.62 ± 138.86 N and 913.73 ± 175.79 N, respectively. The novel PAC-ZnO-ThyH composite film can be used as an active food packaging for promising seafood applications.

An analysis combining proteomics and transcriptomics revealed a regulation target of sea cucumber autolysis.

Sea cucumber is a valuable seafood product and autolysis is the main concern for the aquaculture industry. This study employed proteomics and transcriptomics to investigate the autolysis mechanism of sea cucumbers. The fresh sea cucumber was exposed to UV light to induce autolysis. The body wall samples were cut off to analyze by proteomics and transcriptomics. The angiotensin-converting enzyme (ACE) inhibitor of teprotide and the activator of imatinib were gastric gavage to live sea cucumbers, respectively, to identify the regulation target. Autolysis occurrence was evaluated by appearance, soluble peptide, and hydroxyproline content. Four gene-protein pairs were ACE, AJAP10923, Heme-binding protein 2-like, and Ficolin-2-like. Only the ACE protein and gene changed synchronously and a significant down-regulation of ACE occurred in the autolysis sea cucumbers. Teprotide led to a 1.58-fold increase in the TCA-soluble protein content and a 1.57-fold increase in hydroxyproline content. No significant differences were observed between imatinib-treated sea cucumbers and fresh ones regarding TCA-soluble protein content or hydroxyproline levels (P > 0.05). ACE inhibitor accelerated the autolysis of sea cucumber, but ACE activator inhibited the autolysis. Therefore, ACE can serve as a regulatory target for autolysis in sea cucumbers.

An improved ant colony optimization for solving the flexible job shop scheduling problem with multiple time constraints.

The flexible job shop scheduling problem is important in many research fields such as production management and combinatorial optimization, and it contains sub-problems of machine assignment and operation sequencing. In this paper, we study a many-objective FJSP (MaOFJSP) with multiple time constraints on setup time, transportation time and delivery time, with the objective of minimizing the maximum completion time, the total workload, the workload of critical machine and penalties of earliness/tardiness. Based on the given problem, an improved ant colony optimization is proposed to solve the problem. A distributed coding approach is proposed by the problem features. Three initialization methods are proposed to improve the quality and diversity of the initial solutions. The front end of the algorithm is designed to iteratively update the machine assignment to search for different neighborhoods. Then the improved ant colony optimization is used for local search of the neighborhood. For the searched scheduling set the entropy weight method and non-dominated sorting are used for filtering. Then mutation and closeness operations are proposed to improve the diversity of the solutions. The algorithm was evaluated through experiments based on 28 benchmark instances. The experimental results show that the algorithm can effectively solve the MaOFJSP problem.

Oral administration of sea cucumber (Stichopus japonicus) protein exerts wound healing effects via the PI3K/AKT/mTOR signaling pathway.

This study aimed to investigate the effect of the oral administration of sea cucumber protein (SCP) on wound healing. SCP was isolated and purified from the body wall of Stichopus japonicus. A mouse skin incision model was operated on to evaluate the wound repair effect of SCP. The histological changes in the skin at the wound sites of BALB/c mice were observed by staining with haematoxylin and eosin (H&E) and Masson's trichrome. The enzyme-linked immunosorbent assay (ELISA) was used to analyze the expression of inflammatory cytokines in BALB/c mice. The boost cell migration ability was detected by a scratch assay after HaCaT cells were cultured with digested SCP (dSCP). Western blotting and RT-PCR assays were performed to determine the mechanism of SCP promoting wound healing. As a result, the wound healing rate in the SCP high dose group was 1.3-fold, compared to that in the blank group on day 14. Also, increased epidermal thickness and 1.79-fold collagen deposition contrasted with the blank group. Additionally, SCP could up-regulate the levels of pro-inflammatory factors (IL-1ß, IL-6, TNF-α) from day 3 to 7 firstly and decreased from day 7 to 14. IL-8 expression continuously decreased while the level of anti-inflammatory factor (IL-10) increased during the healing stage. Furthermore, the cell closure area reached 67% after being treated with 50 µg mL-1 of dSCP for 48 h. Cell proliferation was associated with the dSCP-activated PI3K/AKT/mTOR pathway. Taken together, SCP can be orally used as an effective agent for wound repair.

A Sulfated Abalone Polysaccharide Inhibited SARS-CoV-2 Infection of Vero E6 Cells In Vitro.

Sulfate polysaccharides, such as heparin sulfate, have been found to have inhibitory activity against SARS-CoV-2. An abalone polysaccharide, AGSP, was deeply sulfate modified using the chlorosulfonic acid/pyridine method, yielding S-AGSP. AGSP and S-AGSP inhibitions of SARS-CoV-2 infection of Vero E6 cells were tested in vitro. The interference of AGSP or S-AGSP on the binding interaction between the SARS-CoV-2 spike protein and angiotensin-converting enzyme was tested using a biolayer interferometry assay. Results showed that S-AGSP, above a concentration of 1.87 µg/mL, significantly inhibited SARS-CoV-2 infection of Vero E6 cells. Compared with AGSP, S-AGSP obviously weakened the affinity between the SARS-CoV-2 spike protein and ACE2. The polysaccharide's sulfate content played a vital role in influencing the binding affinity of spike protein to ACE2. Therefore, S-AGSP has potential as a COVID-19 competitive inhibitor as well as a candidate to be repurposed as a prophylactic COVID-19 therapeutic.

Stichopus japonicus Polysaccharide Stimulates Osteoblast Differentiation through Activation of the Bone Morphogenetic Protein Pathway in MC3T3-E1 Cells.

This study aimed to examine the combined use of bone morphogenetic protein-2 (BMP-2) and polysaccharide isolated from Stichopus japonicus on osteogenic differentiation of MC3T3-E1 cells. Osteogenic differentiation was measured via histochemical staining of alkaline phosphatase (ALP) assay, alizarin red staining of mineralization assay, Western blotting, ELISA, and a qRT-PCR evaluation for the expression of BMP-2, runt-related transcription factor-2 (Runx-2), osteocalcin (OCN), osteopontin (OPN), and collagen type I (Col I) in MC3T3-E1 cells. Immunofluorescence assay was utilized to assess the BMP-2 localized on the cell surface. The results illustrated that SP-2 was able to increase ALP expression and accelerate the mineralization. Osteoblasts cultured on BMP-2/SP-2 substrate increased the expression levels of BMP-2, Runx-2, Col I, OCN, and OPN. SP-2 increased the binding efficiency involving a BMP-2 and its cell surface receptor. The dose of 5 µg/mL SP-2 used showed the best function of inducing osteoblast differentiation. These findings indicated that SP-2 is a more effective enhancer that cooperated with BMP-2 to induce osteoblastic differentiation by utilizing the BMP-2 signaling pathway.