![]() Consistent with this hypothesis, several genes involved in sialic acid biology have experienced higher rates of non-synonymous substitutions in the human lineage than their counterparts in other great apes, perhaps in response to ancient pathogens that infected hominins millions of years ago (paleopathogens). Because of their role in immunity, sialic acid biology genes have been hypothesized to exhibit elevated rates of evolutionary change. In humans, at least 58 genes spanning diverse functions, from biosynthesis and activation to recycling and degradation, are involved in sialic acid biology. Sialic acids are nine carbon sugars ubiquitously found on the surfaces of vertebrate cells and are involved in various immune response-related processes. Moon, Jiyun M Aronoff, David M Capra, John A Abbot, Patrick Rokas, Antonis PMID:24600589Įxamination of Signatures of Recent Positive Selection on Genes Involved in Human Sialic Acid Biology. In this review, we discuss the history of this field, mechanisms of Neu5Gc incorporation into tissues, the origin and specificities of human anti-Neu5Gc antibodies, their use as possible cancer biomarkers, implications of xenosialitis in cancer initiation and progression, and current and future approaches toward immunotherapy that could take advantage of this unusual human-specific phenomenon. Experimental evidence in a human-like Neu5Gc-deficient Cmah−/−mouse model shows that inflammation due to “xenosialitis†caused by this antigen–antibody interaction can promote tumor progression, suggesting a likely mechanism for the well-known epidemiological link between red meat consumption and carcinoma risk. Such anti-Neu5Gc “xeno-autoantibodies†are found in all humans, although ranging widely in levels among individuals, and displaying diverse and variable specificities for the underlying glycan. Early life exposure to Neu5Gc-containing foods in the presence of certain commensal bacteria that incorporate dietary Neu5Gc into lipooligosaccharides can lead to generation of antibodies that are also cross-reactive against Neu5Gc-containing glycans in human tissues (“xeno-autoantigensâ€). However, Neu5Gc is metabolically incorporated into human tissues from dietary sources (particularly red meat), and detected at even higher levels in some human cancers. Neu5Gc is notable for its deficiency in humans due to a species-specific and species-universal inactivating deletion in the CMAH gene encoding the hydroxylase that converts CMP-Neu5Ac to CMP-Neu5Gc. The predominant sialic acids on most mammalian cells are N-glycolylneuraminic acid (Neu5Gc) and N-acetylneuraminic acid (Neu5Ac). Sialic acids are common monosaccharides that are widely expressed as outer terminal units on all vertebrate cell surfaces, and play fundamental roles in cell–cell and cell–microenvironment interactions. Just watch it, and spread it, and talk about it, and love it, and envy it, and love it more.Involvement of a Non-Human Sialic Acid in Human Cancer I understand why she wants to make it her own.but she already made it her own when I saw PRINCE FLIPPIN ERIC AND MAX(Which was a nice touch) It wasn't like the ORIGINAL vocals and sound and whatnot. The one thing I didn't like.was it sounded more of.a.remix. Like.her real voice, omg her voice is soooo pretty. No animitronic(as far as I could see, looks so real) No nothing! OMG HIS EYES! His eyes were sooo beautful.NO! they ARE beautiful! THEY EVER HAD MAX! like the REAL dog. It was so gorgeous.not to mention Prince Eric. I mean, she cosplays her so good.i'm starting to think she is ariel! When I watched her new video, Part of your world Music video.I was in awe. She's a WONDERFUL AMAZING AWESOME FLAWLESS BEAUTIFUL MERMAID! I bet you guys all know who TRACY HINES is? ![]()
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