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Biomaterial, Host, and Microbial Interactions
Published in Mary Anne S. Melo, Designing Bioactive Polymeric Materials for Restorative Dentistry, 2020
The effects of Bis-HPPP and TEG on the growth and gene expression of cariogenic bacteria have been investigated. The ability of cariogenic bacteria to break down dietary sucrose into glucan through enzymes such as glucosyltransferase allows bacteria to adhere to the tooth surface and protects them from enzymes, antimicrobial agents, and other toxic compounds present in the oral cavity (Kawai and Tsuchitani 2000). By securing adhesion of bacteria to teeth and allowing synthesized acid to remain in contact with the enamel, glucosyltransferase activity, therefore, has a crucial role in the onset of biofilm and caries formation (Singh et al. 2009; Tsumori and Kuramitsu 1997).
Biosynthesis and Genetics of Lipopolysaccharide Core
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
David E. Heinrichs, Chris Whitfield, Miguel A. Valvano
In the first molecular-genetic studies on LPS core OS assembly, a Salmonella waaG mutant was functionally complemented with plasmids containing E. coli K-12 DNA from the Clarke and Carbon collection. The Ffm phage-sensitivity pattern (R-LPS) of the mutant was restored to the Ffm phage-resistant pattern of a smooth strain (89). Enzyme activity from the product of the cloned gene was confirmed as UDP-glucose: (heptosyl) lipopolysaccharide α-1,3-glucosyltransferase. Heterologous complementation of this Salmonella mutation is not surprising given the identical structures in this region of the core OS. The Salmonella waaG gene was subsequently cloned using a similar complementation strategy (90) and has recently been sequenced (149). Pairwise alignments of the deduced amino acid sequences of WaaG proteins from Salmonella and E. coli K-12, Rl, R2, R3, and R4 strains yield values with 85% similarity in all cases (147), correlating with the conserved glucose-α-1,3-heptose structure. A homolog of WaaG has been identified in P. aeruginosa (91,92), although its precise function is unclear since the corresponding part of the P. aeruginosa core OS has a galactosaminyl-heptose structure.
The Development of Improved Therapeutics through a Glycan- “Designer” Approach
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
With the availability of many oligosaccharyltransferases and multiple glycosyltransferases a chemoenzymatic glycosylation is becoming the method of choice. This is because the glycosylation can be controlled efficiently and is suitable for complex carbohydrates. Glycosyltransferases extend the sugar chain by the attachment of one monosaccharide at a time. For example, conjugation of GlcNAc to the lactose moiety of enkephalin was done using acetylglucosaminyltransferase derived from Neisseria species. With the current dynamic research in exploring new glycosyltransferases (e.g., database GlyTouCan) from different species, the chemoenzymatic glycosylation would be one of the most precise methods for glycosylation of therapeutics.
Potential oral probiotic Lactobacillus pentosus MJM60383 inhibits Streptococcus mutans biofilm formation by inhibiting sucrose decomposition
Published in Journal of Oral Microbiology, 2023
Mingkun Gu, Joo-Hyung Cho, Joo-Won Suh, Jinhua Cheng
S. mutans can secrete glucansucrase (also known as glucosyltransferase), an extracellular enzyme, to split sucrose and utilize the resulting glucose molecules to build exopolysaccharide, thereby contributing to the pathogenesis of dental caries [46]. We found that sucrose decomposition was reduced by the treatment of L. pentosus MJM60383 supernatant throughout the time course. This result suggested that the L. pentosus MJM60383 supernatant may inhibit the enzyme activities of glucansucrases or their expression. Ahn, Ki Bum et al. reported [26] that lipoteichoic acid of L. plantarum KCTC10887BP, a cell-wall component of gram-positive bacteria, reduced the biofilm formation of S. mutans by interfering with sucrose decomposition and resulted in the reduction of exopolysaccharide synthesis. However, to the best of our knowledge, this is the first report that Lactobacillus culture supernatant decreased S. mutans biofilm formation by inhibiting sucrose decomposition.
Determination of histopathological effects and myoglobin, periostin gene-protein expression levels in Danio rerio muscle tissue after acaricide yoksorrun-5EC (hexythiazox) application
Published in Drug and Chemical Toxicology, 2023
Yücel Başımoğlu Koca, Serdar Koca, Zübeyde Öztel, Erdal Balcan
We found that following yoksorrun (hexythiazox) treatments, myoglobin level was increased, depending on the skeletal muscle atrophy. This can point at two things: firstly, the acaricide may have reduced the oxygen content of the water. Secondly, oxygen may be insufficient in the muscle tissue due to muscle damage. Therefore, the unknown myoglobin gene expression mechanisms may be induced in intact and/or slightly damaged muscle cells to obtain the required oxygen. On the other hand, previous reports suggested that this pesticide is highly toxic to larvae of Tetranychus urticae but not harmful for deutonymph and adults (Dekeyser 2005, Leviticus et al.2020). More recently, Demaeght et al. (2014) proposed that hexythiazox binds to central pore region of chitin synthase enzyme and block the chitin translocation (Demaeght et al.2014). In a recent study, the regulatory effect of glycogen synthase and glycogen phosphorylase on chitin biosynthesis was investigated (Zhang et al.2019). Glycogen synthase is a key glycosyltransferase in the glycogen biosynthesis. Muscle glycogen is an essential energy source during mechanical action. To evaluate the glycogen content in hexythiazox-treated zebrafish skeletal muscle, we performed PAS technique. Our results indicated that glycogen is decreased upon the pesticide treatment. These data suggest that hexythiazox is not only responsible for the loss of muscle mass in zebrafish but also responsible for the decreasing of glycogen deposits in the skeletal muscles.
Echinocandins – structure, mechanism of action and use in antifungal therapy
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Mateusz Szymański, Sandra Chmielewska, Urszula Czyżewska, Marta Malinowska, Adam Tylicki
The synthesis of β-(1,3)-d-glucan is catalysed by UDP-glucose (1,3)-d-glucan-β-(3)-d-glucosyltransferase, referred to as β-(1,3)-d-glucan synthase (EC 2.4.1.34)45. This enzyme uses UDP-glucose as a reaction substrate to form β-(1,3)-d-glycosidic bonds46. The enzyme is a transmembrane heteromeric glycosyltransferase consisting of at least two subunits. The Fks1p subunit (encoded by the FKS1, FKS2, and FKS3 genes) has a catalytic function, while the Rho1p subunit (belonging to the GTPase family) has a regulatory function. Echinocandins binding non-competitively to the Fks1p subunit of the enzyme inhibits its activity47,48. Blocking β-(1,3)-d-glucan biosynthesis leads to structural abnormalities of the fungal cell wall (Figure 13), resulting in growth inhibition or death by imbalance in osmotic pressure49. The fungicidal or fungistatic effects of echinocandins have been confirmed for most species of the Candida and Aspergillus genera50.