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Turbo cornutus is an edible sea snail species whose viscera parts are by-products of fish processing. Although they can be used for human consumption as good sources of functional ingredients, they are generally discarded. The objective of the present study was to prepare bioactive hydrolysate (MSVAH) from viscera parts of T. cornutus using enzymatic hydrolysis, and to investigate their antioxidant and anti-hyaluronidase properties for use as potential functional food ingredients. In MSVAH, taurine was found to be the most abundant. Taurine is known to have excellent physiological activity. Taurine-enriched MSVAH showed good capacities of DPPH, peroxyl radical scavenging, and hyaluronidase inhibition, with IC50 values of 0.50 mg/mL, 0.32 mg/mL, and 2.87 mg/mL, respectively. MSVAH also significantly improved cell viability and inhibited intracellular reactive oxygen species (ROS) dose-dependently against oxidative stress induced by 2,2-azobis-(2-amidinopropane) dihydrochloride (AAPH), a free-radical-generating compound, in immortalized human keratinocytes (HaCaT cells). Furthermore, MSVAH upregulated hyaluronic acid (HA)-synthesizing enzyme hyaluronan synthase 2 (HAS2) expression level, but downregulated expression level of HA-degrading enzyme hyaluronidase 2 (HYAL2), resulting in increased HA production in keratinocytes. Taken together, these results suggest that taurine-enriched MSVAH derived from viscera parts of T. cornutus, known to be by-products of fish processing, could be used to prepare potential bioactive hydrolysates for developing functional foods and nutraceutical products. [ABSTRACT FROM AUTHOR]

Maintaining stability of replication forks is important for genomic integrity. However, it is not clear how replisome proteins contribute to fork stability under replication stress. Here, we report that ATAD5, a PCNA unloader, plays multiple functions at stalled forks including promoting its restart. ATAD5 depletion increases genomic instability upon hydroxyurea treatment in cultured cells and mice. ATAD5 recruits RAD51 to stalled forks in an ATR kinase-dependent manner by hydroxyurea-enhanced protein-protein interactions and timely removes PCNA from stalled forks for RAD51 recruitment. Consistent with the role of RAD51 in fork regression, ATAD5 depletion inhibits slowdown of fork progression and native 5-bromo-2ʹ-deoxyuridine signal induced by hydroxyurea. Single-molecule FRET showed that PCNA itself acts as a mechanical barrier to fork regression. Consequently, DNA breaks required for fork restart are reduced by ATAD5 depletion. Collectively, our results suggest an important role of ATAD5 in maintaining genome integrity during replication stress. How the replisome machinery contributes to fork stability under replication stress is currently not clear. Here the authors reveal a role for ATAD5 in maintaining genome integrity during replication stress by promoting replication restart through RAD51/PCNA regulation. [ABSTRACT FROM AUTHOR]

Bioactive peptides isolated from edible marine sources have been used as nutraceuticals and functional foods. The present study focuses on the alcalase hydrolysate of Hippocampus abdominalis for the isolation of antioxidative and angiotensin-I converting enzyme (ACE) inhibitory peptides. Initially, the H. abdominalis alcalase hydrolysate (HA) was separated using ultrafiltration (MWCO = 5 kDa), and have obtained the fraction, HA-III (MW ≤ 5 kDa), with strong bioactivity. This was further separated using gel filtration chromatography (Sephadex G-10) and reverse-phase high-performance liquid chromatography (RP-HPLC). The active Sephadex G-10 fraction was analyzed by the Q-TOF mass spectrometry, nine peptides were identified within the molecular mass range between 757.8 and 990.1 Da. Three peptides, GIIGPSGSP, IGTGIPGIW, and QIGFIW, showed strong ACE inhibitory activity and alkyl radical-scavenging activity. Molecular docking studies revealed that the ACE inhibitory activity of the three active peptides is mainly due to hydrogen bonding interactions and active site interactions between active peptides and ACE. This study demonstrated that the active peptides derived from H. abdominalis can be isolated and the proteolytic hydrolysates of it are potential antioxidant and antihypertensive agents. [ABSTRACT FROM AUTHOR]

Angiotensin I-converting enzyme (ACE) inhibitory peptide was purified from krill ( Euphausia superba) protein hydrolysate using consecutive chromatography using an SP-Sephadex C-25 cation exchanger and then reverse-phase high-performance liquid chromatography. The purified ACE inhibitory peptide was identified to be Ile-Pro-Ile-Lys with a molecular weight of 470.3 Da by LC-MS/MS. The IC value of Ile-Pro-Ile-Lys was 57.4 µM. Lineweaver-Burk plots suggest that Ile-Pro-Ile-Lys acts as a non-competitive inhibitor against ACE. Oral administration of Ile-Pro-Ile-Lys significantly ( p < 0.05) decreased the systolic blood pressure of spontaneously hypertensive rats. Collectively, an antihypertensive peptide purified from krill protein hydrolysates may be useful as a food ingredient for treatment of hypertension and related diseases. [ABSTRACT FROM AUTHOR]

The antidiabetogenic and antioxidative effects of octaphlorethol A (OPA) isolated from the brown algae Ishige foliacea in streptozotocin (STZ)-induced diabetic mice were analyzed. STZ-induced diabetic mice showed a significant ( p<0.05) increase in blood glucose and lipid peroxidation levels and a significant ( p<0.05) decrease in the plasma insulin level and body weight, compared with controls. Diabetic mice also showed a significant ( p<0.05) decrease in the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px), compared with controls. Oral treatment with OPA (5 and 10 mg/kg) showed protective effects against all the biochemical parameters studied. OPA-treated mice exhibited suppression of apoptosis, and treatment with OPA was associated with an increase in antiapoptotic BclxL expression and a reduction in pro-apoptotic Bax and cleaved caspase-3 expressions. OPA has antidiabetogenic and antioxidative effects, and potential for use in therapies as both a natural functional food and a pharmaceutical agent. [ABSTRACT FROM AUTHOR]

In this study, an antioxidative peptide was obtained by hydrolyzation of mideodeok (Styela clava) flesh tissue with various proteases and purified through gel filtration chromatography and reverse phage-HPLC (RPHPLC), and then antioxidant activity was investigated using electron spin resonance (ESR) spectrometer. Among the enzymatic hydrolysates, the peptic hydrolysate exhibited the highest antioxidant activity, and a strong antioxidant peptide was purified from the hydrolysate. The peptide sequence, Leu-Trp-His-Thr-His (692.2 Da), was identified by quardruple time-of-flight electrospray ionization (QTOF ESI)-MS. This antioxidative peptide strongly scavenged peroxyl radical with the IC value of 39.4 μM. [ABSTRACT FROM AUTHOR]