Research progress in the effects of terahertz waves on biomacromolecules.

With the rapid development of terahertz technologies, basic research and applications of terahertz waves in biomedicine have attracted increasing attention. The rotation and vibrational energy levels of biomacromolecules fall in the energy range of terahertz waves; thus, terahertz waves might interact with biomacromolecules. Therefore, terahertz waves have been widely applied to explore features of the terahertz spectrum of biomacromolecules. However, the effects of terahertz waves on biomacromolecules are largely unexplored. Although some progress has been reported, there are still numerous technical barriers to clarifying the relation between terahertz waves and biomacromolecules and to realizing the accurate regulation of biological macromolecules by terahertz waves. Therefore, further investigations should be conducted in the future. In this paper, we reviewed terahertz waves and their biomedical research advantages, applications of terahertz waves on biomacromolecules and the effects of terahertz waves on biomacromolecules. These findings will provide novel ideas and methods for the research and application of terahertz waves in the biomedical field.

Enantiomeric Excess Determination for Monosaccharides Using Chiral Transmission to Cold Gas-Phase Tryptophan in Ultraviolet Photodissociation.

Chiral transmission between monosaccharides and amino acids via photodissociation in the gas phase was examined using a tandem mass spectrometer fitted with an electrospray ionization source and a cold ion trap in order to investigate the origin of the homochirality of biomolecules in molecular clouds. Ultraviolet photodissociation mass spectra of cold gas-phase noncovalent complexes of the monosaccharide enantiomers glucose (Glc) and galactose (Gal) with protonated L-tryptophan H+(L-Trp) were obtained by photoexcitation of the indole ring of L-Trp. L-Trp dissociated via Cα-Cß bond cleavage when noncovalently complexed with D-Glc; however, no dissociation of L-Trp occurred in the homochiral H+(L-Trp)(L-Glc) noncovalent complex, where the energy absorbed by L-Trp was released through the evaporation of L-Glc. This enantioselective photodissociation of Trp was due to the transmission of chirality from Glc to Trp via photodissociation in the gas-phase noncovalent complexes, and was applied to the quantitative chiral analysis of monosaccharides. The enantiomeric excess of monosaccharides in solution could be determined by measuring the relative abundance of the two product ions in a single photodissociation mass spectrum of the cold gas-phase noncovalent complex with H+(L-Trp), and by referring to the linear relationships derived in this work. Graphical Abstract ᅟ.

Tellurium nanotubes synthesized with microwave-assisted monosaccharide reduction method.

A microwave-assisted monosaccharide reducing approach has been developed in the preparation of tellurium nanotubes. The as-prepared tellurium nanotubes have the sizes of 50 - 100 nm in diameter, and a few micrometers in length. A series of contrastive experiments have illustrated that microwave-heating contributed a lot in the synthesis, and the decomposition of H2TeO3 to TeO2 and low reducibility of the monosaccharide played a key role in the process. The possible mechanism of the synthesis of the nanotubes has been preliminarily discussed.

Reductive ring opening of o-nitrobenzylidene acetals of monosaccharides: synthesis and photolysis of some photolabile sugars.

[figure: see text] A 6-O-o-nitrobenzyl methylglucoside and methylmannoside were synthesized by reacting 4,6-O-o-nitrobenzylidene acetals with triethylsilane and boron trifluoride etherate. A 2,6-di-O-o-nitrobenzyl and a 3,6-di-O-o-nitrobenzyl methylmannoside were obtained from a 2,3:4,6-di-O-o-nitrobenzylidene methylmannoside by the same method. The photolabile sugars obtained were deprotected by irradiation at 350 nm to afford methylglycosides.

Reactivity of cartilage and selected carbohydrates with hydroxyl radicals: an NMR study to detect degradation products.

It was investigated to what extent isolated, monomeric and polymeric carbohydrates as well as cartilage specimens are affected by hydroxyl radicals generated by gamma-irradiation or Fenton reaction and what products can be detected by means of NMR spectroscopy. Resonances of all protons in glucose and other monosaccharides as well as carbon resonances in 13C-enriched glucose were continuously diminished upon gamma-irradiation. Formate and malondialdehyde were found as NMR detectable products in irradiated glucose solutions under physiologically relevant (aerated) conditions. In polysaccharide solutions (e.g. hyaluronic acid) gamma-irradiation and also treatment with the Fenton reagent caused first an enhancement of resonances according to mobile N-acetyl groups at 2.02 ppm. This indicates a breakdown of glycosidic bonds in polysaccharides. Using higher radiation doses or higher concentrations of the Fenton reagent formate was also detected. The same sequence of events was observed upon treatment of bovine nasal cartilage with the Fenton reagent. First, glycosidic linkages in cartilage polysaccharides were cleaved and subsequently formate was formed. In contrast, collagen of cartilage was affected only to a very low extent. Thus, HO-radicals caused the same action on cartilage as on isolated polymer solutions, inducing a fragmentation of polysaccharides and the formation of formate.

Glucose transport carrier of human erythrocytes. Radiation target size measurement based on flux inactivation.

Intact human erythrocytes frozen in the presence of cryoprotective reagents and irradiated with an electron beam retained their diffusion barrier to L-glucose. The carrier-mediated flux of D-glucose, on the other hand, was inactivated as a simple exponential function of the radiation dose. Classical target size analysis of this data yielded a molecular size of 185,000 daltons for the carrier. This represents the first measurement of the functional size of a transport protein based directly on flux inactivation.

[Effect of salts and sole of metal oxides on radiochemical changes in carbohydrates and abiogenic amino acid synthesis]. / Vliianie solei i zolei okislov metallov na radiatsionno-khimicheskie izmeneniia uglevodov i abiogennyi sintez aminokislot.

It has been shown that gamma-irradiation of solutions of carbohydrates in the presence of sulfates and metal oxide sols results in oxidative and destructive processes and leads to formation of carbonile compounds, organic acids, H2CO, and a substance with lambda max= =261 nm. With respect to their catalytic effect on carbohydrate changes, the sulfates and metal oxide sols investigated may be arranged into the following order: CuSO4 > > MnSO4=NiSO4 > ZnSO4 > H2O (salt free glucose solution); MoO3 > V2O5 > Al2O3 > > H2O (glucose solution without metal oxide sol). Radiolysis of glucose, mannose and arabinose is affected by the nature of gas saturating the solutions: O2 > Ar > CO2. Ionizing irradiation of solutions of hexoses and pentoses which contain nitrates as the source of nitrogen, results in the formation of amino acids with the chain length from 2 to 6 atoms of carbon (gly, ser, lys, ala, asp, his, tre, val, glu).

Radiation-induced DNA strand breaks in deoxygenated aqueous solutions. The formation of altered sugars as end groups.

Gamma irradiation of DNA in deoxygenated, N2O-saturated aqueous solution leads to three bound altered sugars present as end groups in broken DNA strands. These sugars are linked to the DNA by phosphoric acid ester bonds. Two of the end groups have the structures (4) and (5). (Formula: see text) The third end group after dephosphorylation has structure (3). The formation of the bound sugars (4) and (5) is explained by a mechanism postulated earlier for the formation of free altered sugars. Except for the phosphoric acid ester linkage, the free altered sugars have the same chemical structures as the bound altered sugars.

[Abiogenic photochemical synthesis of amino acids in an aqueous medium containing carbohydrates and nitrates]. / Abiogennyi fotokhimicheskii sintez aminokislot v vodnoi srede, soderzhaesschei uglevody i nitraty

Ultraviolet light (PRK-2) induces the formation of various amino acids (lysine, asparaginic, as well as traces of some other acids) in mannose, glucose and arabinose solutions containing various nitrates. K+, Co2+, Ni2+ and Fe3+ significantly sensitize the formation of amino acids. In the atmosphere of N2, synthesis of appreciable amounts of glutamic acid takes place, wherease in the atmosphere of O2 or CO2 the latter is produced only in traces. Photolysis of glucose and mannose in nitrate-free solutions in the atmosphere of N2 results in the formation of lysine and glutamic acid. The data obtained show that in pre-biologic conditions in the hydrosphere of Earth (possibly, of other planets as well), abiogenically formed organic substances, e. g. carbohydrates, unter the influence of UV irradiation could be transformed into amino acids. Nitrates present in the water milieu could serve as a source of nitrogen in the amino acids synthesis.