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Seaweeds are some of the largest producers of biomass in the marine environment and are rich in bioactive compounds that are often used for human and animal health. Porphyran and carrageenan are natural compounds derived from red seaweeds. The former is a characteristic polysaccharide of Porphyra, while the latter is well known from Chondrus, Gigartina, and various Eucheuma species, all in Rhodophyceae. The two polysaccharides have been found to have anti-cancer activity by improving immunity and targeting key apoptotic molecules and therefore deemed as potential chemotherapeutic or chemopreventive agents. This review attempts to review the current study of anti-cancer activity and the possible mechanisms of porphyran and carrageenan derived from red seaweeds to various cancers, and their cooperative actions with other anti-cancer chemotherapeutic agents is also discussed.

The sushi factor One of the useful roles performed by the human gut microbiota is to supply digestive enzymes missing from the human genome. For instance, polysaccharides from the terrestrial plants that have been part of the human diet throughout evolution are broken down in the gut by carbohydrate active enzymes, or CAZymes, many of them highly specific enzymes from Bacteroides spp. bacteria. Little is known about the gut enzymes acting on edible marine algae such as nori, sea lettuce and wakame, common in Japanese cuisine. Now CAZymes able to digest sulphated polysaccharides from Porphyra sp. marine red algae have been identified in marine Bacteroides isolates. And surprisingly, genome data mining reveals that this enzyme is present in gut bacteria from Japanese — but not American — individuals. This demonstrates that the gene transfer has taken place — recently in evolutionary terms — from a marine environmental bacterium to the Japanese gut bacterium Bacteroides plebeius . Porphyra are otherwise known as nori and used traditionally in sushi, so it seems probable that contact with non-sterile food may be a general factor in stocking gut microbes with a varied arsenal of CAZymes. One of the roles of the human gut microbiota is to break down nutrients using bacterial enzymes that are lacking from the human genome. It is now shown that the gut microbiota of Japanese, but not American, individuals contains porphyranases, enzymes that digest sulphated polysaccharides which are present in the marine environment only. These findings indicate that diet can select for gene content of the human microbiota. Gut microbes supply the human body with energy from dietary polysaccharides through carbohydrate active enzymes, or CAZymes 1 , which are absent in the human genome. These enzymes target polysaccharides from terrestrial plants that dominated diet throughout human evolution 2 . The array of CAZymes in gut microbes is highly diverse, exemplified by the human gut symbiont Bacteroides thetaiotaomicron 3 , which contains 261 glycoside hydrolases and polysaccharide lyases, as well as 208 homologues of susC and susD -genes coding for two outer membrane proteins involved in starch utilization 1 , 4 . A fundamental question that, to our knowledge, has yet to be addressed is how this diversity evolved by acquiring new genes from microbes living outside the gut. Here we characterize the first porphyranases from a member of the marine Bacteroidetes, Zobellia galactanivorans , active on the sulphated polysaccharide porphyran from marine red algae of the genus Porphyra . Furthermore, we show that genes coding for these porphyranases, agarases and associated proteins have been transferred to the gut bacterium Bacteroides plebeius isolated from Japanese individuals 5 . Our comparative gut metagenome analyses show that porphyranases and agarases are frequent in the Japanese population 6 and that they are absent in metagenome data 7 from North American individuals. Seaweeds make an important contribution to the daily diet in Japan (14.2 g per person per day) 8 , and Porphyra spp. (nori) is the most important nutritional seaweed, traditionally used to prepare sushi 9 , 10 . This indicates that seaweeds with associated marine bacteria may have been the route by which these novel CAZymes were acquired in human gut bacteria, and that contact with non-sterile food may be a general factor in CAZyme diversity in human gut microbes.

Appropriate isolation methods are essential for unravelling the relative contribution of extracellular vesicles (EVs) and the EV-free secretome to homeostasis and disease. We hypothesized that ultrafiltration followed by size exclusion chromatography (UF-SEC) provides well-matched concentrates of EVs and free secreted molecules for proteomic and functional studies. Conditioned media of BEAS-2B bronchial epithelial cells were concentrated on 10 kDa centrifuge filters, followed by separation of EVs and free protein using sepharose CL-4B SEC. Alternatively, EVs were isolated by ultracentrifugation. EV recovery was estimated by bead-coupled flow cytometry and tuneable resistive pulse sensing. The proteomic composition of EV isolates and SEC protein fractions was characterized by nano LC-MS/MS. UF-SEC EVs tended to have a higher yield and EV-to-protein rate of purity than ultracentrifugation EVs. UF-SEC EVs and ultracentrifugation EVs showed similar fold-enrichments for biological pathways that were distinct from those of UF-SEC protein. Treatment of BEAS-2B cells with UF-SEC protein, but not with either type of EV isolate increased the IL-8 concentration in the media whereas EVs, but not protein induced monocyte adhesion to endothelial cells. Thus, UF-SEC is a useful alternative for ultracentrifugation and allows comparing the proteomic composition and functional effects of EVs and free secreted molecules.

The dense microbial ecosystem in the gut is intimately connected to numerous facets of human biology, and manipulation of the gut microbiota has broad implications for human health. In the absence of profound perturbation, the bacterial strains that reside within an individual are mostly stable over time 1 . By contrast, the fate of exogenous commensal and probiotic strains applied to an established microbiota is variable, generally unpredictable and greatly influenced by the background microbiota 2 , 3 . Therefore, analysis of the factors that govern strain engraftment and abundance is of critical importance to the emerging field of microbiome reprogramming. Here we generate an exclusive metabolic niche in mice via administration of a marine polysaccharide, porphyran, and an exogenous Bacteroides strain harbouring a rare gene cluster for porphyran utilization. Privileged nutrient access enables reliable engraftment of the exogenous strain at predictable abundances in mice harbouring diverse communities of gut microbes. This targeted dietary support is sufficient to overcome priority exclusion by an isogenic strain 4 , and enables strain replacement. We demonstrate transfer of the 60-kb porphyran utilization locus into a naive strain of Bacteroides , and show finely tuned control of strain abundance in the mouse gut across multiple orders of magnitude by varying porphyran dosage. Finally, we show that this system enables the introduction of a new strain into the colonic crypt ecosystem. These data highlight the influence of nutrient availability in shaping microbiota membership, expand the ability to perform a broad spectrum of investigations in the context of a complex microbiota, and have implications for cell-based therapeutic strategies in the gut. Finely tuned control of strain engraftment and abundance in the mouse gut microbiota was achieved using the marine polysaccharide porphyran, which could exclusively be used by an introduced subset of wild-type or genetically modified Bacteroides strains.

Alginate oligosaccharides (AlgO), agarose oligosaccharides (AO), and κ-carrageenan oligosaccharides (KCO) were obtained by specific enzymatic hydrolysis method. The molecular weight distributions of the three oligosaccharides were 1.0–5.0 kDa, 0.4–1.4 kDa, and 1.0–7.0 kDa, respectively. The culture medium was supplemented with the three oligosaccharides and fermented by pig fecal microbiota in vitro, for 24 h. Each oligosaccharide was capable of increasing the concentration of short-chain fatty acids (SCFAs), especially butyric acid, and altering the microbiota composition. Linear discriminant analysis effect size (LEfSe) analysis results showed that the opportunistic pathogenic bacteria Escherichia, Shigella, and Peptoniphilus, were significantly decreased in AlgO supplemented medium. AO could improve the gut microbiota composition by enriching the abundance of Ruminococcaceae, Coprococcus, Roseburia, and Faecalibacterium. Besides, KCO could increase the abundance of SCFA microbial producers and opportunistic pathogenic flora. Therefore, these results indicate that AlgO and AO can be used as gut microbial regulators and can potentially improve animal/human gastrointestinal health and prevent gut disease, whereas the physiological function of KCO needs further evaluation.

Intervertebral disc (IVD) degeneration is the leading cause of low back pain in young adults, and the cartilaginous endplate (CEP) is likely to play a key role in early IVD degeneration. To elucidate the effects of pro-inflammatory cytokines on the mechanobiology of the CEP, human CEP cells were seeded into 2% agarose, dynamically compressed up to 7%, and stimulated with tumor necrosis factor (TNF). It was hypothesized that dynamic compression would be sufficient to induce anabolism, while stimulation with TNF would induce catabolism. TNF was sufficient to induce a catabolic, time-dependent response in human CEP cells through downregulation of anabolic gene expression and increased secretion of pro-inflammatory proteins associated with herniated discs, bacteria inhibition, and pain. However, 7% strain or scaffold material, agarose, may not lead to full activation of integrins and downregulation of pro-inflammatory pathways, demonstrated in part through the unchanged gene expression of integrin subunits α 5 and β 1 .

Mechanical aspects of the cellular environment can influence cell function, and in this context hydrogels can serve as an instructive matrix. Here we report that physicochemical properties of hydrogels derived from polysaccharides (agarose, κ-carrageenan) having an α-helical backbone can be tailored by inducing a switch in the secondary structure from α-helix to β-sheet through carboxylation. This enables the gel modulus to be tuned over four orders of magnitude (G′ 6 Pa–3.6 × 10 ⁴ Pa) independently of polymer concentration and molecular weight. Using carboxylated agarose gels as a screening platform, we demonstrate that soft-carboxylated agarose provides a unique environment for the polarization of endothelial cells in the presence of soluble and bound signals, which notably does not occur in fibrin and collagen gels. Furthermore, endothelial cells organize into freestanding lumens over 100 μm in length. The finding that a biomaterial can modulate soluble and bound signals provides impetus for exploring mechanobiology paradigms in regenerative therapies.

Lipoprotein lipase (LPL), the enzyme that hydrolyzes triglycerides in plasma lipoproteins, is assumed to be active only as a homodimer. In support of this idea, several groups have reported that the size of LPL, as measured by density gradient ultracentrifugation, is ∼110 kDa, twice the size of LPL monomers (∼55 kDa). Of note, however, in those studies the LPL had been incubated with heparin, a polyanionic substance that binds and stabilizes LPL. Here we revisited the assumption that LPL is active only as a homodimer. When freshly secreted human LPL (or purified preparations of LPL) was subjected to density gradient ultracentrifugation (in the absence of heparin), LPL mass and activity peaks exhibited the size expected of monomers (near the 66-kDa albumin standard). GPIHBP1-bound LPL also exhibited the size expected for a monomer. In the presence of heparin, LPL size increased, overlapping with a 97.2-kDa standard. We also used density gradient ultracentrifugation to characterize the LPL within the high-salt and low-salt peaks from a heparin-Sepharose column. The catalytically active LPL within the high-salt peak exhibited the size of monomers, whereas most of the inactive LPL in the low-salt peak was at the bottom of the tube (in aggregates). Consistent with those findings, the LPL in the low-salt peak, but not that in the high-salt peak, was easily detectable with single mAb sandwich ELISAs, in which LPL is captured and detected with the same antibody. We conclude that catalytically active LPL can exist in a monomeric state.

The Sec complex catalyzes the translocation of proteins of the secretory pathway into the endoplasmic reticulum and the integration of membrane proteins into the endoplasmic reticulum membrane. Some substrate peptides require the presence and involvement of accessory proteins such as Sec63. Recently, a structure of the Sec complex from Saccharomyces cerevisiae , consisting of the Sec61 channel and the Sec62, Sec63, Sec71 and Sec72 proteins was determined by cryo-electron microscopy (cryo-EM). Here, we show by co-precipitation that the Sec61 channel subunit Sbh1 is not required for formation of stable Sec63-Sec61 contacts. Molecular dynamics simulations started from the cryo-EM conformation of Sec61 bound to Sec63 and of unbound Sec61 revealed how Sec63 affects the conformation of Sec61 lateral gate, plug, pore region and pore ring diameter via three intermolecular contact regions. Molecular docking of SRP-dependent vs. SRP-independent signal peptide chains into the Sec61 channel showed that the pore regions affected by presence/absence of Sec63 play a crucial role in positioning the signal anchors of SRP-dependent substrates nearby the lateral gate.

A major hindrance in engineering tissues containing highly metabolically active cells is the insufficient oxygenation of these implants, which results in dying or dysfunctional cells in portions of the graft. The development of methods to increase oxygen availability within tissue-engineered implants, particularly during the early engraftment period, would serve to allay hypoxia-induced cell death. Herein, we designed and developed a hydrolytically activated oxygen-generating biomaterial in the form of polydimethylsiloxane (PDMS)-encapsulated solid calcium peroxide, PDMS-CaO2. Encapsulation of solid peroxide within hydrophobic PDMS resulted in sustained oxygen generation, whereby a single disk generated oxygen for more than 6 wk at an average rate of 0.026 mM per day. The ability of this oxygen-generating material to support cell survival was evaluated using a β cell line and pancreatic rat islets. The presence of a single PDMS-CaO2 disk eliminated hypoxia-induced cell dysfunction and death for both cell types, resulting in metabolic function and glucose-dependent insulin secretion comparable to that in normoxic controls. A single PDMS-CaO2 disk also sustained enhanced β cell proliferation for more than 3 wk under hypoxic culture conditions. Incorporation of these materials within 3D constructs illustrated the benefits of these materials to prevent the development of detrimental oxygen gradients within large implants. Mathematical simulations permitted accurate prediction of oxygen gradients within 3D constructs and highlighted conditions under which supplementation of oxygen tension would serve to benefit cellular viability. Given the generality of this platform, the translation of these materials to other cell-based implants, as well as ischemic tissues in general, is envisioned.