IRW (Ile-Arg-Trp) was identified as an inhibitor of angiotensin converting enzyme (ACE) from egg white protein ovotransferrin through an integrated in silico digestion and quantitative structure and ...activity relationship prediction in 2011. Oral administration of IRW to spontaneously hypertensive rats (SHRs) can significantly reduce blood pressure, via upregulation of ACE2, but not through the inhibition of ACE. ACE2 converts Ang II into Ang (1-7), thus lowering blood pressure via Mas receptor (MasR); coinfusion of Mas receptor antagonist A779 and IRW in SHRs abolished blood pressure-lowering effect of IRW, supporting a key role of ACE2/Ang (1-7)/MasR axis. Our ongoing study further established new roles of IRW as an antioxidant, an anti-inflammatory agent, an insulin sensitizer, and a bone cell anabolic. Future studies are warranted to understand the unique structure features of this peptide, its mechanisms of action at various targets, its bioavailability and metabolism, and its possible roles toward COVID-19.
Observation of surface water is a functional requirement for studying ecological and hydrological processes. Recent advances in satellite‐based optical remote sensors have promoted the field of ...sensing surface water to a new era. This paper reviews the current status of detecting, extracting, and monitoring surface water using optical remote sensing, especially progress in the last decade. It also discusses the current status and challenges in this field, including spatio‐temporal scale issues, integration with in situ hydrological data and elevation data, obscuration caused by clouds and vegetation, and the growing need to map surface water at a global scale. Historically, sensors have exhibited a contradiction in resolutions. Techniques including pixel unmixing and reconstruction, and spatio‐temporal fusion have been developed to alleviate this contradiction. Spatio‐temporal dynamics of surface water have been modeled by combining remote sensing data with in situ river flow. Recent studies have also demonstrated that the river discharge can be estimated using only optical remote sensing imagery, providing valuable information for hydrological studies in ungauged areas. Another historical issue for optical sensors has been obscuration by clouds and vegetation. An effective approach of reducing this limitation is to combine with synthetic aperture radar data. Digital elevation model data have also been employed to eliminate cloud/terrain shadows. The development of big data and cloud computation techniques makes the increasing demand of monitoring global water dynamics at high resolutions easier to achieve. An integrated use of multisource data is the future direction for improved global and regional water monitoring.
Plain Language Summary
Observing surface water is essential for ecological and hydrological studies. This paper reviews the current status of detecting, extracting, and monitoring surface water using optical remote sensing, especially progress in the last decade. It also discusses the current status and challenges in this field. For example, it was found that pixel unmixing and reconstruction, and spatio‐temporal fusion are two common and low‐cost approaches to enhance surface water monitoring. Remote sensing data have been integrated with in situ river flow to model spatio‐temporal dynamics of surface water. Recent studies have also proved that the river discharge can be estimated using only optical remote sensing imagery. This will be a breakthrough for hydrological studies in ungauged areas. Optical sensors are also easily obscured by clouds and vegetation. This limitation can be reduced by integrating optical data with synthetic aperture radar data and digital elevation model data. There is increasing demand of monitoring global water dynamics at high resolutions. It is now easy to achieve with the development of big data and cloud computation techniques. Enhanced global or regional water monitoring in the future requires integrated use of multiple sources of remote sensing data.
Key Points
Satellite‐based optical sensors are an efficient means for observing surface water regionally and globally
Pixel unmixing and reconstruction, and spatio‐temporal fusion are two common and low‐cost approaches to enhance surface water monitoring
The potential to estimate flow using only optical remote sensing has greatly enriched the data source of hydrological studies
Bioactive peptides (BAPs) play a crucial physiological role in human health. To exert their biological effects after oral administration, BAPs have to be transported across the human intestinal ...barrier into the blood circulation system, and must reach their targets in an intact or active form. However, few reviews have summarized current understanding of BAP transport to exhibit activities (bioavailability) and its knowledge gaps.
To obtain a better insight into BAP absorption and aid the design of improved functional foods for humans, this review summarizes and discusses the mechanistic transport pathways, modulatory factors, human studies, solutions to improve the bioavailability, and future perspectives of BAPs.
Both passive (paracellular and passive transcellular diffusion) and active (transporter and transcytosis) routes are possible involved in the BAP transport process, which can be influenced by various properties of peptides, including hydrophobicity, charge, size, molecular weight, amino acid sequence, stability, and enzymatic degradation. Peptidase-resistant BAPs can be transported into the bloodstream at concentrations in the micromolar range and remain intact for several minutes to hours to excise bioactivities. Studies of the effects of BAPs in humans are required, and the bioavailability of BAPs will be at the forefront of future functional food research.
•Transport mechanisms of bioactive peptide are reviewed.•Both passive and active routes may be involved in transporting bioactive peptides.•Transport can be affected by various properties of bioactive peptides.•Bioactive peptides are transported intact into human blood to exert bioactivities.•More studies on the bioavailability of BAPs are required.
SUMMARY
We determine robust 3-D P-wave anisotropic tomography of the crust and upper mantle beneath NE China using high-quality traveltime data of local earthquakes and teleseismic events recorded at ...334 network and portable stations. In the upper crust, nearly E-W fast-velocity directions (FVDs) of azimuthal anisotropy are revealed in the central Songliao basin, which is surrounded by circular-shaped FVDs along the basin edges. The E-W FVDs may reflect microcracks or fractures in the upper crust, which are aligned under the control of regional tectonic stress. In the lower crust, low-velocity (low-V) anomalies with NE-SW FVDs exist along the Tanlu fault zone, which may reflect NE-SW trending ductile deformation or viscous flow along the fault zone. The FVDs are mainly NNW-SSE to N-S in the uppermost mantle beneath most of the study region, which may reflect fossil deformation of the mantle lithosphere caused by the Palaeo-Pacific plate subduction. High-velocity anomalies with NE-SW FVDs are revealed at ∼100 km depth directly beneath the Great XingAn Mountain, which may reflect an old lithospheric remnant. In the deep upper mantle, the FVDs are mostly NW-SE, consistent with SKS splitting measurements, which may be closely related to the intermittently retreating stagnant Pacific slab beneath East Asia. Under the Changbai and other intraplate volcanoes in NE China, prominent low-V anomalies exist in the big mantle wedge (BMW) above the slab in the mantle transition zone, suggesting that these volcanoes are caused by hot and wet upwelling flows in the BMW closely associated with the deep subduction and dehydration of the western Pacific plate.
•Low-molecular-weight collagen peptides are associated with various health benefits.•Enzymatic hydrolysis remains the major way to prepare LMW collagen hydrolysates.•Cross-link and hydroxyproline in ...collagen contributes to its resistance to hydrolysis.
Collagen hydrolysates (peptides) derived from food processing byproducts have been used to produce commercially valuable food ingredients due to their potential to trigger certain desirable physiological responses in the body. Low-molecular-weight (LMW) collagen hydrolysates are generally thought to exert better bioactivities than their larger counterparts. However, the preparation of LMW collagen hydrolysates is often impeded by their special structure, cross-linking, and hydroxyproline. This review briefly introduces the motivation of the food industry to prepare LMW collagen hydrolysate from food processing byproducts. We further summarize recent progress on the preparation of LMW collagen hydrolysates and methods to determine the molecular weight. We then discuss the challenges and then provide perspectives on future directions in preparing LMW collagen hydrolysates.
We report the cryo-EM structure of the human 26S proteasome at an average resolution of 3.5 Å, allowing atomic modeling of 28 subunits in the core particle (CP) and 18 subunits in the regulatory ...particle (RP). The C-terminal residues of Rpt3 and Rpt5 subunits in the RP can be seen inserted into surface pockets formed between adjacent α subunits in the CP. Each of the six Rpt subunits contains a bound nucleotide, and the central gate of the CP α-ring is closed despite RP association. The six pore 1 loops in the Rpt ring are arranged similarly to a spiral staircase along the axial channel of substrate transport, which is constricted by the pore 2 loops. We also determined the cryo-EM structure of the human proteasome bound to the deubiquitinating enzyme USP14 at 4.35-Å resolution. Together, our structures provide a framework for mechanistic understanding of eukaryotic proteasome function.
In this study, the egg yolk livetins (α, β, and γ-livetin) fraction and its hydrolysates, prepared by pepsin and Alcalase, were evaluated for their anti-inflammatory effects using lipopolysaccharide ...(LPS)-induced RAW 264.7 macrophages as an in vitro model. Enzymatic hydrolysis by pepsin and Alcalase successfully transformed the large molecular weight livetins into low molecular mass peptides mostly below 10kDa. Results revealed that livetins and its hydrolysates (peptides) treatment significantly reduced the inflammatory responses as evidenced by inhibition of production of nitric oxide (NO) (22.7–39.2%), pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) (36.9–43.2%), interleukin-1β (IL-1β) (26.1–50.9%) and interleukin-6 (IL-6) (60.4–69.0%), and the expression of inducible nitric oxide synthase (iNOS) (58.6–62%). Alcalase hydrolysate showed more effects in inhibiting prostaglandin-E2 (PGE2) production (30.3%) as well as expression of cyclooxygenase-2 (COX-2) (55.7%). In addition, effect of livetins and its hydrolysates on phagocytic capacity of the macrophages was also evaluated. The results indicate that livetins and its enzymatic hydrolysates significantly (p<0.001, 0.05) enhanced the phagocytic activity of the macrophages. The results suggest that egg yolk livetins and its hydrolysates with anti-inflammatory activity can potentially be used in health food/nutraceutical/pharmaceutical industry for various applications.
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•The egg yolk livetins fraction and its enzymatic hydrolysates showed anti-inflammatory effects in LPS-induced RAW 264.7 macrophages.•Livetins and pepsin hydrolysate inhibited NO, iNOS, TNF-α, IL-1β, IL-6, and IL-10.•Alcalase hydrolysate inhibited NO, PGE2, COX-2, TNF-α, IL-1β, and IL-6.•Livetins and its hydrolysates have been shown to have phagocytosis enhancing capacity.•Livetins and its hydrolysates could be useful in food and pharmaceutical industries.
There is growing interest in using functional foods or nutraceuticals for the prevention and treatment of hypertension or high blood pressure. Although numerous preventive and therapeutic ...pharmacological interventions are available on the market, unfortunately, many patients still suffer from poorly controlled hypertension. Furthermore, most pharmacological drugs, such as inhibitors of angiotensin-I converting enzyme (ACE), are often associated with significant adverse effects. Many bioactive food compounds have been characterized over the past decades that may contribute to the management of hypertension; for example, bioactive peptides derived from various food proteins with antihypertensive properties have gained a great deal of attention. Some of these peptides have exhibited potent in vivo antihypertensive activity in both animal models and human clinical trials. This review provides an overview about the complex pathophysiology of hypertension and demonstrates the potential roles of food derived bioactive peptides as viable interventions targeting specific pathways involved in this disease process. This review offers a comprehensive guide for understanding and utilizing the molecular mechanisms of antihypertensive actions of food protein derived peptides.
Intake of antioxidants through diet is known to be important in reducing oxidative damage in cells and improving human health. Although eggs are known for their exceptional, nutritional quality, they ...are not generally considered as antioxidant foods. This review aims to establish the importance of eggs as an antioxidant food by summarizing the current knowledge on egg-derived antioxidants. Eggs have various natural occurring compounds including the proteins ovalbumin, ovotransferrin and lysozyme in egg white, as well as phosvitin, carotenoids and free aromatic amino acids in egg yolk. Some lipophilic antioxidants such as vitamin E, carotenoids, selenium, iodine and others can be transferred from feed into egg yolk to produce antioxidant-enriched eggs. The bioactivity of egg antioxidants can be affected by food processing, storage and gastrointestinal digestion. Generally thermal processing methods can promote loss of antioxidant properties in eggs due to oxidation and degradation, whereas gastrointestinal digestion enhances the antioxidant properties, due to the formation of new antioxidants (free amino acids and peptides). In summary, in addition to its well-known nutritional contribution to our diet, this review emphasizes the role of eggs as an important antioxidant food.
Milk derived tripeptides IPP (Ile-Pro-Pro) and VPP (Val-Pro-Pro) have shown promise as anti-hypertensive agents due to their inhibitory effects on angiotensin converting enzyme (ACE). Due to the key ...inter-related roles of hypertension, chronic inflammation and insulin resistance in the pathogenesis of metabolic syndrome, there is growing interest in investigating established anti-hypertensive agents for their effects on insulin sensitivity and inflammation. In this study, we examined the effects of IPP and VPP on 3T3-F442A murine pre-adipocytes, a widely used model for studying metabolic diseases. We found that both IPP and VPP induced beneficial adipogenic differentiation as manifested by intracellular lipid accumulation, upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) and secretion of the protective lipid hormone adiponectin by these cells. The observed effects were similar to those induced by insulin, suggesting potential benefits in the presence of insulin resistance. IPP and VPP also inhibited cytokine induced pro-inflammatory changes such as reduction in adipokine levels and activation of the nuclear factor kappa B (NF-κB) pathway. Taken together, our findings suggest that IPP and VPP exert insulin-mimetic adipogenic effects and prevent inflammatory changes in adipocytes, which may offer protection against metabolic disease.
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