Aromatic O-glycosylation

Carbohydrates carrying an aromatic aglycon are important natural products and thus key synthetic targets. However, due to the electron-withdrawing properties of aromatic rings, phenols are difficult to glycosylate. This review covers the most common carbohydrate donors used for aromatic O-glycosylation (anomeric acetates, halides, trichloroacetimidates and thioglycosides) as well as some less common donors. The scope of the review is to give practical examples of aromatic O-glycosylations and to offer guidelines for glycosylation of typical aromatic residues. Anomeric acetates or trichloroacetimidates, activated under acidic conditions, are preferred for electron rich aromatic aglycons, while glycosyl halides, activated using basic conditions, are preferred for electron deficient aromatic residues.     

Role of reactive aldehyde in cardiovascular diseases

There is increasing evidence that aldehydes generated endogenously during the degradation process of biological molecules are involved in many of the pathophysiologies associated with cardiovasular diseases such as atherosclerosis and the long-term complications of diabetes. Major sources of reactive aldehydes in vivo are lipid peroxidation, glycation, and amino acid oxidation. Although the types of aldehydes are varied, the important aldehydes that can exert biological effects relevant to the pathobiology of oxidant injury are represented by 2-alkenals, 4-hydroxy-2-alkenals, and ketoaldehydes. These aldehydes exhibit facile reactivity with proteins, generating stable products at the end of a series of reactions. The protein-bound aldehydes can be detected as constituents not only in in vitro oxidized low-density lipoproteins but also in animal models of atherosclerosis and in human patients with increased risk factors or clinical manifestations of atherosclerosis, indicating that they could indeed be involved in the caldiovascular pathology. On the other hand, a number of reactive aldehydes have been implicated as inducers in generating intracellular oxidative stress and activation of stress signaling pathways, that integrate with other signaling pathways to control cellular responses to the extracellular stimuli.     

云南香型软米水稻资源农艺性状遗传效应研究

选取5份云南地方香型软米水稻种质资源和6份自育香型软米保持系按5×6不完全双列杂交设计(NCⅡ)配制成30个组合,采用加性-显性-上位性遗传模型,分析云南香型软米11个农艺性状的遗传效应。结果表明,云南香型软米多数农艺性状的遗传主要受加×加上位性效应、加性×环境效应、显性×环境效应的影响,还存在不同程度的加性效应和显性效应,单株产量受基因加性效应、显性效应、加×加上位性效应、加性×环境效应、显性×环境效应的影响;株高、有效穗的遗传率以普通狭义遗传率为主,其他性状的普通狭义遗传率和互作狭义遗传率均达极显著水平;产量构成性状之间存在不同类型和不同程度的遗传相关,多数性状之间以加×加上位性、加性×环境和显性×环境互作效应显著。     

Modeling tyrosinase activity. Effect of ligand topology on aromatic ring hydroxylation: an overview

Synthetic modeling of tyrosinase (o-phenol ring hydroxylation) has emerged as a novel class of successful biomimetic studies. It is a well-established fact that the reaction of dioxygen with copper(I) complexes of m-xylyl-based ligands generate putative copper-oxygen intermediate species such as side-on peroxo {CuII2(mu-O2)}2+ [in some cases bis-oxo {CuIII2(mu-O)2}2+ in equilibrium with isomeric side-on peroxo], due to oxygen activation. Electrophilic attack of such species brings about monooxygenase activity by incorporating one of the oxygens to m-xylyl ring of the ligand and the other oxygen is reduced to hydroxide ion. The goal of this review is to provide a concise overview of the present day knowledge in this field of research to emphasize the important role the designed ligands play in eliciting the desired tyrosinase-like chemistry.     

Synthesis and characterization of highly functionalized symmetric aromatic hexa-ol intermediates from oleic acid

A novel highly functionalized aromatic hexa-ol was synthesized by palladium-catalyzed cyclotrimerization of an alkyne fatty acid ester followed by LAH reduction. This polyol product is a novel monomer made from a renewable lipid raw material for the production of polyurethanes, polyesters and polyamides.     

Evaluating the biodegradation of aromatic hydrocarbons by monitoring of several functional genes

Various microbial activities determine the effectiveness of bioremediation processes. In this work, we evaluated the feasibility of gene array hybridization for monitoring the efficiency of biodegradation processes. Biodegradation of ¹⁴C-labelled naphthalene and toluene by the aromatic hydrocarbon-degrading Pseudomonas putida F1, P. putida mt-2 and P. putida G7 was followed in mixed liquid culture microcosm by a preliminary, nylon membrane-based gene array. In the beginning of the study, toluene was degraded rapidly and increased amount of toluene degradation genes was detected by the preliminary gene array developed for the study. After toluene was degraded, naphthalene mineralization started and the amount of naphthalene degradation genes increased as biodegradation proceeded. The amount of toluene degradation genes decreased towards the end of the study. The hybridization signal intensities determined by preliminary gene array were in good agreement with mineralization of naphthalene and toluene and with the amount of naphthalene dioxygenase and toluene dioxygenase genes quantified by dot blot hybridization. The clear correlation between the results obtained by the preliminary array and the biodegradation process suggests that gene array methods can be considered as a promising tool for monitoring the efficiency of biodegradation processes.     

Aromatic-aromatic interactions in the formation of the MDM2-p53 complex

Although the molecular interaction of MDM2 with the transactivation domain of p53 has been thoroughly studied, there is very limited information regarding the steps involved in the recognition mechanism between these proteins. On this basis, we performed four high-temperature molecular dynamics simulations in explicit solvent to gain insight into the interactions involved in the fist contact toward the formation of the complex. We found that the presence of specific intermolecular aromatic pairs at the interface of the complex, around the native-like state of MDM2, is consistent among independent molecular dynamics runs. This observation suggests that aromatic-aromatic interactions are closely related to the first contact between MDM2 and p53. Thus, we propose that aromatic-aromatic interactions are an important, and probably essential, requirement for the formation and stabilization of the MDM2-p53 complex.     

芘在土壤中的共代谢降解研究

高分子量多环芳烃（PAHs)的降解通常以共代谢方式进行,研究比较了高分子量多环芳烃代表种类芘作为唯一C源和能源的降解过程和有共代谢底物存在下的降解过程,结果表明,25d后前者中芘的降解率57％,而后者中芘的降解率为80％,且有共代谢底物存在下,芘在降解过程中关衰期缩短;水扬酸,邻苯二甲酸,琥珀酸钠能作为共代谢底物提高芘的降解率,琥珀酸钠效果最好,芘和低要子量多环芳烃之间也有共代谢关系,菲促进了芘的降解,但萘未出现同样的结果,此外,这阐明了共代谢原理和适宜作高分子量多环芳烃共代谢底物的物质。