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Torovirus
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Ziton Abdulrida Ighewish Al-Khafaji, Ghanim Aboud Al-Mola
By SDS-PAGE, BRV was shown to possess five structural polypeptides with similar molecular weights to those found in BEV. The BRV N and M proteins possess similar properties to those of BEV [18,24,33]. The 37 kDa matrix protein thought to be associated with the envelope is also present. The N-glycosylated S protein migrates as two bands with Mr of 85 and 105 kDa, which probably arise following posttranslational processing of the BRV S protein precursor. A fifth BRV protein with a Mr of 65 kDa, which was initially not thought to be virus specific [29], has recently been shown to represent a novel hemagglutinin-esterase protein [34]. This protein is N-glycosylated and displays acetylesterase activity as demonstrated in an in situ esterase assay developed for the HE fusion protein of influenza C virus [35].
Prediction of long-term polysorbate degradation according to short-term degradation kinetics
Published in mAbs, 2023
Sisi Zhang, Caterina Riccardi, Dane Carlson, Douglas Kamen, Kenneth S. Graham, Mohammed Shameem, Hanne Bak, Hui Xiao, Ning Li
Several enzymes from CHO cell lines capable of degrading PS have been detected and reported, including lipoprotein lipase (LPL), lysosomal acid lipase (LAL), group XV lysosomal phospholipase A2 isomer X1 (LPLA2), liver carboxylesterase, sialate O-acetylesterase (SIAE) and palmitoyl-protein thioesterase 1 (PPT1).1,4,6,16–23,26–28 The activity of each lipase markedly differs; for example, lipases/esterases such as LPLA2 and carboxylesterase cause substantial PS degradation at levels below parts per million (ppm),20,23,29 whereas other lipases/esterases cause PS degradation at ppm levels or higher.17,19 SIAE targets only PS20 but not PS80,16,18 whereas other enzymes degrade both PS20 and PS80. Despite their different activities, these PS-degrading enzymes are commonly identified in DPs from different cell lines prepared through different processes used across the biopharmaceutical industry.26,27 Therefore, understanding the properties of each individual lipase/esterase would be helpful and have broad applications.
Carbohydrates great and small, from dietary fiber to sialic acids: How glycans influence the gut microbiome and affect human health
Published in Gut Microbes, 2021
Joanna K Coker, Oriane Moyne, Dmitry A. Rodionov, Karsten Zengler
Although most research has been done on Neu5Ac, microbes can also act on modifications of Neu5Ac or on other sialic acids (Figure 3a). Neu5Ac modified with an O-acetyl group is generally resistant to release by sialidases. However, recent studies of B. fragilis show the O-acetylesterase EstA removes 9-O-acetyl esterifications, allowing sialidases to release these modified Neu5Ac molecules and promote in vitro growth of E. coli.113 Although not confirmed in vivo yet, this could provide another example of bacterial interactions to share metabolic capabilities. Previous studies of the commensal anaerobe Ruminococcus gnavus showed it cannot grow on unmodified Neu5Ac alone and instead uses an intramolecular trans-sialidase to release 2,7-anhydro-Neu5Ac from α2-3-linked sialic acids.114 2,7-anhydro-Neu5Ac is then selectively transported across the Ruminococcus cell membrane and converted back to Neu5Ac for further metabolism.115 This strategy, which prevents other organisms from utilizing the uncommon 2,7-anhydro-Neu5Ac, seems designed to conserve resources for R. gnavus as opposed to the cross-talk seen in other sialic acid processing pathways. While the major part of sialidase research focuses on Neu5Ac, some recent studies have examined the activity of gut microbe sialidases on Neu5Gc. Zaramela et al.116 reported the discovery of Neu5Gc-preferential sialidases from the gut microbiome of the Hadza hunter-gatherer group,4 with four out of the five selected Bacteroides sialidases displaying preferential release of Neu5Gc over Neu5Ac in at least one of the tested conditions. Further exploration of metabolism of these and other sialic acid modifications will undoubtedly reveal more novel microbial strategies to harvest sialic acids.