Biosynthesis Of Complex Carbohydrates Research Articles

Insights into the biodegradation and heavy metal resistance potential of the genus Brevibacillus through comparative genome analyses

Members of the genus Brevibacillus belonging to the familyPaenibacillaceae are Gram-positive/variable, endospore-forming, and rod-shaped bacteria that dwell in various environmental habitats. Brevibacillus spp. have a wide range of enzyme activities such as degradation of various carbohydrates, plastics, and they possess resistance against heavy metals. These characteristics make them encouraging contenders for biotechnological applications.In this work, we analyzed the reference genomes of 19Brevibacillusspecies, focusing on discovering the biodegradation and heavy metal resistance capabilities of this little studied genus from genomic data. The results indicate that several strain specific traits were identified. For example Brevibacillus halotolerans s-14, and Brevibacillus laterosporus DSM 25 have more glycoside hydrolases (GHs) compared to other carbohydrate-active enzymes, and therefore might be more suitable for biodegradation of carbohydrates. In contrast, strains such as Brevibacillus antibioticus TGS2-1, with a higher number of glycosyltransfereases (GTs) may aid in the biosynthesis of complex carbohydrates. Our results also suggest some correlation between heavy metal resistance and polyurethane degradation, thus indicating that heavy metal resistance strains (e.g. Brevibacillus reuszeri J31TS6) can be a promising source of enzymes for polyurethane degradation. These strain specific features make the members of this bacterial group potential candidates for further investigations with industrial implications. This work also represents the first exhaustive study of Brevibacillus at the genome scale.

GTXplorer: A portal to navigate and visualize the evolutionary information encoded in fold A glycosyltransferases.

Glycosyltransferases (GTs) play a central role in sustaining all forms of life through the biosynthesis of complex carbohydrates. Despite significant strides made in recent years to establish computational resources, databases and tools to understand the nature and role of carbohydrates and related glycoenzymes, a data analytics framework that connects the sequence-structure-function relationships to the evolution of GTs is currently lacking. This hinders the characterization of understudied GTs and the synthetic design of GTs for medical and biotechnology applications. Here, we present GTXplorer as an integrated platform that presents evolutionary information of GTs adopting a GT-A fold in an intuitive format enabling in silico investigation through comparative sequence analysis to derive informed hypotheses about their function. The tree view mode provides an overview of the evolutionary relationships of GT-A families and allows users to select phylogenetically relevant families for comparisons. The selected families can then be compared in the alignment view at the residue level using annotated weblogo stacks of the GT-A core specific to the selected clade, family, or subfamily. All data are easily accessible and can be downloaded for further analysis. GTXplorer can be accessed at https://vulcan.cs.uga.edu/gtxplorer/ or from GitHub at https://github.com/esbgkannan/GTxplorer to deploy locally. By packaging multiple data streams into an accessible, user-friendly format, GTXplorer presents the first evolutionary data analytics platform for comparative glycomics.

Sucrose transport in the phloem: integrating root responses to phosphorus starvation

Sugars in plants, derived from photosynthesis, act as substrates for energy metabolism and the biosynthesis of complex carbohydrates, providing sink tissues with the necessary resources to grow and to develop. In addition, sugars can act as secondary messengers, with the ability to regulate plant growth and development in response to biotic and abiotic stresses. Sugar-signalling networks have the ability to regulate directly the expression of genes and to interact with other signalling pathways. Photosynthate is primarily transported to sink tissues as sucrose via the phloem. Under phosphorus (P) starvation, plants accumulate sugars and starch in their leaves. Increased loading of sucrose to the phloem under P starvation not only functions to relocate carbon resources to the roots, which increases their size relative to the shoot, but also has the potential to initiate sugar-signalling cascades that alter the expression of genes involved in optimizing root biochemistry to acquire soil phosphorus through increased expression and activity of inorganic phosphate transporters, the secretion of acid phosphatases and organic acids to release P from the soil, and the optimization of internal P use. This review looks at the evidence for the involvement of phloem sucrose in co-ordinating plant responses to P starvation at both the transcriptional and physiological levels.

Biosynthesis of Proteoglycans and Hyaluronic Acid by Rat Oral Epithelial Cells (Keratinocytes) in Vitro

Biosynthesis of complex carbohydrates, including sulfated glycoproteins, hyaluronic acid (HA), and proteoglycans (PGs), synthesized by rat oral epithelial cells (keratinocytes) in culture were studied by metabolic labeling protocols using [35S]sulfate and [3H]glucosamine in combination with differential enzymatic digestion and analytical gel filtration. The epithelial cells synthesized a major sulfated glycoprotein species with an apparent molecular size ∼50 kDa, which accounted for approximately 46% of the total 35S incorporation. HA was a relatively minor component of 3H-labeled macromolecules (∼4% of the total 3H incorporation), and almost all of it was secreted into the medium. PGs accounted for approximately half of the 35S incorporation, of which about 30% was secreted into the medium and the remainder associated with the cell layer. The majority of PGs (75% of the secreted and 97% of the cell-associated) contained heparan sulfate (HS) and had an apparent molecular weight of ∼150,000. Cell-associated HSPGs had a core protein of ∼70 kDa with HS chains of ∼64 kDa, while HSPG in the medium had a core protein of ∼50 kDa with HS chains of the same average size as those of the cell-associated HSPG. Of the total cell-associated HSPGs, glycosylphosphatidyl inositol-anchored forms, plasma membrane intercalated forms and those associated with basolateral pericellular matrix accounted for ∼3%, 56% and ∼4% of the total, respectively. Approximately one third of the cell-associated HSPGs were intracellular components most likely generated through intracellular degradation processes following endocytosis. Cell surface HSPGs synthesized by keratinocytes may be involved in some biological roles such as the regulation of normal epithelial turnover and defense mechanisms involving interactions with various oral pathogens.

New developments in the synthesis of phosphopolyprenols and their glycosyl esters.

Efficient methods were developed in our group in recent years for chemical synthesis of polyprenyl phosphates, polyprenyl monophosphate sugars, and polyprenyl diphosphate sugars, which were known to serve as important intermediates in biosynthesis of complex carbohydrates. A simple procedure was developed involving the phosphorylation of aliphatic alcohols with tetra-n-butylammonium dihydrogen phosphate and trichloroacetonitrile. Monophosphates of various natural and modified dolichols and polyprenols, as well as the derivatives of retinol, cholesterol, and nonacosanol, were prepared in high yields. First syntheses of dolichyl thiophosphate and dolichyl hydrogen phosphonate were developed, and these derivatives were of interest as analogs of dolichyl phosphate. Polyprenyl monophosphate sugars, including derivatives of alpha- and beta-anomers of D-glucopyranose, D-galactopyranose, D-mannopyranose, and 2-acetamido-2-deoxy-D-glucopyranose, were obtained smoothly from moraprenyl trichloroacetimidate and acylated glycosyl phosphates after deprotection. A method for the synthesis of polyprenyl diphosphate sugars from polyprenyl phosphoroimidazolidate and unprotected glycosyl phosphates was shown to be applicable for a wide range of the monosaccharide derivatives including hexoses, deoxyhexoses, 2-acetamido-2-deoxyhexoses, and uronic acids. A series of the oligosaccharide derivatives was also prepared by this method.

ChemInform Abstract: Lipid-Linked Sugars as Intermediates in the Biosynthesis of Complex Carbohydrates in Plants

ChemInformVolume 18, Issue 29 Reviews ChemInform Abstract: Lipid-Linked Sugars as Intermediates in the Biosynthesis of Complex Carbohydrates in Plants R. P. LEZICA, R. P. LEZICA Inst. Invest. Biol., Fac. Ci. Exactas Nat., Univ. Nacl. Mar del Plata, 7600 Mar del Plata, ArgentinaSearch for more papers by this authorG. R. DALEO, G. R. DALEO Inst. Invest. Biol., Fac. Ci. Exactas Nat., Univ. Nacl. Mar del Plata, 7600 Mar del Plata, ArgentinaSearch for more papers by this author R. P. LEZICA, R. P. LEZICA Inst. Invest. Biol., Fac. Ci. Exactas Nat., Univ. Nacl. Mar del Plata, 7600 Mar del Plata, ArgentinaSearch for more papers by this authorG. R. DALEO, G. R. DALEO Inst. Invest. Biol., Fac. Ci. Exactas Nat., Univ. Nacl. Mar del Plata, 7600 Mar del Plata, ArgentinaSearch for more papers by this author First published: July 21, 1987 https://doi.org/10.1002/chin.198729376Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume18, Issue29July 21, 1987 RelatedInformation

Biosynthetic controls that determine the branching and microheterogeneity of protein-bound oligosaccharides.

The past ten years have witnessed an unprecedented explosion in our knowledge of complex carbohydrate fine structure. The techniques which have been responsible for these advances include high resolution gel filtration chromatography, high performance liquid chromatography, the availability of a battery of exo- and endo-glycosidases with well-characterized specificities, new chemical methods for cleaving carbohydrate-amino acid linkages, high field nuclear magnetic resonance spectrometry, and high resolution mass spectrometry. It is clear that two properties distinguish complex carbohydrates from proteins and nucleic acids, the other two classes of biological macromolecules, namely: 1) branching and 2) microheterogeneity. These properties pose both challenges and problems for researchers interested in the function and biosynthesis of complex carbohydrates.

Galactosyltransferases: physical, chemical, and biological aspects.

Galactosyltransferases (GTs) are one of the members of a family of enzymes called glycosyltransferases involved in the biosynthesis of complex carbohydrates. These enzymes catalyze the transfer of galactose from UDP-galactose to an acceptor (glycoprotein, glycolipid) containing terminal N-acetylglucosamine or N-acetylgalactosamine residue. GTs occur in soluble (milk, serum, effusions, etc.) and insoluble (membrane) forms. The GT activities on the outer surface of the cells have been correlated with a host of cellular interactions, including fertilization, cell migration, embryonic induction, chondrogenesis, contact inhibition of growth, cell adhesion, hemostasis, intestinal cell differentiation, and immune recognition. GTs have been purified to homogeneity using affinity chromatography. Most GTs are found active in the pH range 6 to 8 and at temperatures between 35 to 40 degrees C. Manganese is an essential co-factor for GT activity. Isoenzymes of GT have been recognized, especially in tumor tissues, malignant effusions, and sera of cancer patients using polyacrylamide gel electrophoresis in the presence and absence of SDS. Depending on the source of the enzyme, the molecular weights of GTs range between 40,000 to 80,000 daltons. Carcinoma-associated GT isoenzyme has been reported to have a higher molecular weight than the normal GT isoenzyme. Development of monoclonal antibody against the cancer-specific GT isoenzyme will provide help in the development of an immunoassay for the measurement of this isoenzyme in the sera and an aid in the radioimmunolocalization of the tumors in cancer patients.

The Role of Lipid-Linked Saccharides in the Biosynthesis of Complex Carbohydrates

Lipid intermediates, or lipid-linked saccharides, were first discovered in bacteria where they were shown to be involved in the biosynthesis of cell wall polymers such as peptidoglycan, lipopolysaccharide, teichoic acid and capsular polysaccharides (Osborn 1969, Hemming 1974). Those studies set the stage for later experiments in eukaryotic systems which also showed the synthesis and utilization of similar types of lipid intermediates in the biosynthesis of complex carbohydrates (Waechter and Lennarz 1976). In this chapter, the lipid intermediates that have been identified in higher plants will be discussed and their role in biosynthetic reactions will be considered. The plant systems will be compared to those studies that have been done in animal and yeast systems. Figure 1 outlines a series of reactions that have been proposed to account for the formation of the lipid-linked oligosaccharide that serves as the final donor in the glycosylation of protein. These reactions are considered in detail in the ensuing pages.