Information capacity of the carbohydrate code

Capacity for information in biological molecules is traditionally thought to reside in the primary sequence of proteins and RNA, recorded in the DNA. With the exception of some RNA molecules, proteins, if not structural, carry their information in binding sites for substrates of reactions, or in binding sites for control molecules. Some proteins bind to complex carbohydrates in a carbohydrate-specific fashion, including enzymes, lectins and antibodies. These carbohydrates, assembled by sequential glycosyl transferases, also carry biological information, the other side of which is a binding protein that recognizes a specific sugar monosaccharides, sequence, anomerity, linkage, ring size, branching and substitution. It is the latter 7 parameters, however, that give carbohydrates a very large potential for information-carrying capacity in a short sequence. An exponentially growing body of knowledge exists in this aspect of carbohydrate function

Fatty acids differ significantly in castes of the Formosan subterranean termite (Isoptera: Rhinotermitidae)

© The Authors 2015. Identification and quantitation of fatty acids (FAs) in nymphs, alates, workers, presoldiers, and soldiers of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were determined by gas chromatography- mass spectrometry, showing quantitative and qualitative differences among groups. Total FAs content of nymphs and alate females was about 1.5-fold higher than alate males, about 2-fold higher than workers, 6-fold higher than presoldiers, and 12-fold higher than soldiers. Overall differences in total FAs content were due to oleic acid (C18:1), stearic acid (C18:0), linoleic acid (C18:2), and palmitic acid (C16:0). Soldiers contained two unique FAs among the castes - lignoceric (C24:0) and hexacosanoic acid (C26:0). Nymphs had the highest ratio between triacylglycerols and phospholipids probably for energy storage in alate development. Four branched FAs - 13-methyl myristic, 14-methyl pentadecenoic, 15-methyl palmitic, and 14-methyl palmitic - and three oddnumbered FAs - pentadecanoic (C15:0), heptadecanoic (C17:0), and heptadecenoic (C17:1) - were found in nymphs, alates, workers, presoldiers, and soldiers. Interestingly, all FAs were distributed in different percentages both in triglycerides and phospholipids of the different developmental stages and castes, indicating a function both for energy storage and membrane components. Five different 2-hydroxy FAs - 2-OH C16:0, 2-OH C18:0, 2-OH C20:0, 2-OH C22:0, and 2-OH C24:0 - were identified, the latter only in soldiers. Total 2-hydroxy FAs content in soldiers was significantly higher than that in other groups (6.01-7.9-fold vs. presoldiers and 41.7- 132.6-fold vs. nymphs, alates, and workers), and the quantity in presoldiers was significantly higher than in nymphs, alates, and workers, with no difference among nymphs, alates, and workers

Dolichyl-phosphomannose synthase from the Archae Thermoplasma acidophilum

Archae (formerly Archaebacteria) comprise an entire kingdom of organisms placed halfway between prokaryotes and eucaryotes in evolution, This class of organisms lacks murein cell wall and is devoid of organelles, yet Archae synthesize and export N-linked and O-linked glycoproteins utilizing only the plasma membrane. Study of glycosylation systems in Archae is extremely interesting because the plasma membrane must perform many functions normally carried out by the endoplasmic reticulum and Golgi in eucaryotes. This report represents the first glycosyl transferase system enzyme demonstrated from archae showing a functional relationship with homologous eucaryotic enzymes. Archae dolichyl-phosphoryl-mannose synthase was purified 1070-fold from Thermoplasma acidophilum by column chromatography on Sephacryl S-200, Cibacron blue 3GA-agarose, Octyl-Sepharose, and hydroxylapatite in the presence of 0.2% polioxyethylene 9 lauryl ether. The enzyme activity was stimulated by MgCl, (20 mM optimum) and exhibited a pH optimum at 6.0. Although the native polyisoprenol has not been isolated or characterized, the enzyme prefers dolichyl phosphate (dol-P) to C55-polyisoprenol as an acceptor, and the K(m) value for dol-P was calculated to be 2.6 μM. Amphomycin, an inhibitor of dol-P-Man synthase, blocked mannosyl transfer to the endogenous lipids, proteins, and to dol-P; 100 μg/ml amphomycin inhibited 97% of mannosyl transfer to dol-P, and 50% to endogenous accepters, indicating direct transfer from GDP-mannose to some intermediates or final structures. The size range of [3H]Man-oligosaccharides from acid-labile manno-lipid product was from dp 1 to 4. dol-P-Man synthase activity could be correlated directly with a 42 kDa band on SDS/polyacrylamide gel electrophoresis

Intrinsic tryptophan fluorescence measurements suggest that polylactosaminyl glycosylation affects the protein conformation of the gelatin‐binding domain from human placental fibronectin

Glycosylation can affect the physical and biochemical properties of the polypeptide chain in glycoproteins. Asparagine‐N‐linked polylactosaminyl glycosylation of the chymotryptic 44‐kDa gelatin‐binding domain from human placental fibronectin confers protease resistance [Zhu, B. C. R., Fisher, S. F., Panda, H., Calaycay, J., Shively, J. E. & Laine, R. A. (1984) J. Biol. Chem. 259, 3962–3970] and weakens the binding to gelatin [Zhu, B. C. R. & Laine, R. A. (1985) J. Biol. Chem. 260, 4041–4045]. Intrinsic tryptophan fluorescence of the gelatinbinding domain was used to probe glycosylation‐dependent protein conformation changes. In gelatin‐binding fragments containing incrementally smaller polylactosamine oligosaccharides, the fluorescence intensity progressively decreased and the emission spectrum shifted about 7 nm to the blue. Removal of the polylactosamine chains from a highly glycosylated fragment with endo‐β‐galactosidase from Escherichia freundii also quenched the protein fluorescence. The fluorescence lifetimes did not appear to be affected by the extent of glycosylation, suggesting static quenching of the tryptophan emission in the low glycosylated fragments. Acrylamide quenching studies showed that the accessibility of the tryptophans to small solutes was not altered by glycosylation. The steadystate emission anisotropy increased with decreasing polylactosamine chain length. The results indicate that the polylactosamine chains alter the tryptophan environments in the gelatin‐binding domain, probably by changing the polypeptide conformation. These putative protein conformation changes may be partially responsible for the altered gelatin binding, protease resistance, and cell adhesion functions of fetal tissue fibronectin. Copyright © 1990, Wiley Blackwell. All rights reserve

Novel free ceramides as components of the soldier defense gland of the Formosan subterranean termite (Coptotermes formosanus)

Of the lipid extracts of the defense secretion from the Formosan subterranean termite, Coptotermes formosanus Shiraki, on high-performance thin-layer chromatography analysis, no glycolipids or phospholipids were detected, but free fatty acids and three novel ceramides were found (termed TL-1, TL-2, and TL-3). Free fatty acids were confirmed to be lignoceric acid (C24:0) and hexacosanoic acid (C26:0), as described previously [Chen, J., G. Henderson, and R. A. Laine. 1999. Lignoceric acid and hexacosanoic acid: major components of soldier frontal gland secretions of the Formosan subterranean termite (Coptotermes formosanus). J. Chem. Ecol. 25: 817-824]. TL-1, TL-2, and TL-3 were characterized as ceramides differing in hydrophobicity based on results of matrix-assisted laser desorption-ionization time-of-flight mass spectrometry analysis, mild alkaline treatment, GC-MS analysis of fatty acid methylesters, and GC-MS analysis of sphingoid long-chain bases (LCBs) as trimethylsilyl derivatives. Fatty acids in TL-1 and TL-2 were C18:0, C20:0, and C22:0, and those in TL-3 were 2-hydroxy C18:0, C20:0, and C22:0. The most predominant LCB in TL-2 was a novel trihydroxy C14-sphingosine, 1,3,9-trihydroxy-2-amino-6-tetradecene. TL-3 contained C18-sphinganine and two kinds of novel sphingadienines, 1,3-dihydroxy-2-amino-7,10-hexadecadiene and 1,3-dihydroxy-2-amino-11,14-eicosadiene. Although examination of the biological activities of these novel ceramides was beyond the scope of these studies, because of the minuscule quantities available from termite secretions, it will be interesting in the future to synthesize these molecules for biological testing. Copyright ©2007 by the American Society for Biochemistry and Molecular Biology, Inc

Formosan subterranean termite (Isoptera: Rhinotermitidae) soldiers regulate juvenile hormone levels and caste differentiation in workers

A caste structure is maintained in termite societies and juvenile hormone (JH) is generally regarded as the most important regulator in these termite colonies. Here, we demonstrate that the soldier caste regulates JH in workers of Coptotermes formosanus Shiraki. Worker termites (80-100 individuals) were placed in petri dishes with 0, 5, 10, or 20% soldiers. JH III titers of groups of these workers were monitored at 14, 28, 42, and 56 d. Any changes in soldier caste proportions also were noted at each sample date. On the first sample date, the JH levels in workers were similar among treatments with different initial soldier proportions, and no new soldiers were formed. Over the next three sample dates, the worker JH levels were higher for low initial soldier proportion treatments and vice versa. Concurrently, soldier formation increased with lower initial soldier proportions. JH titers in workers showed a positive and statistically significant relationship to soldier numbers until a certain soldier proportion was reached. These results provide evidence that soldier caste proportions regulate JH levels and thereby caste differentiation in workers. The means by which this regulatory mechanism may proceed is discussed. © 2005 Entomological Society of America

An efficient and economic asymmetric synthesis of (+)-nootkatone, tetrahydronootkatone, and derivatives

Image Persented A facile route to enantiomerically pure (+)-nootkatone and derivatives has been established through conjunctive stereoselective Grignard/anionic oxy-Cope (AOC) reactions. © 2009 American Chemical Society