肺泡灌洗液结核杆菌RNA和DNA检测在痰菌阴性肺结核诊断中的临床应用

目的观察肺泡灌洗液结核杆菌RNA和DNA检测在痰菌阴性肺结核患者中的阳性检出情况。方法选取2017年3月—2019年3月在我院接受检查和治疗且最终确诊为痰菌阴性肺结核的患者为研究对象,所有患者均接受肺泡灌洗液结核杆菌RNA和DNA检测。分析2种检测方法阳性检出率的差异。结果结核杆菌RNA阳性检出率为63.33%,DNA阳性检出率为33.33%,前者高于后者。结论结核杆菌RNA检测对痰菌阴性肺结核具较高灵敏度,优于DNA检测。

Anomeric configuration-dependence of the Lattrell-Dax epimerization from D-glucose to synthetically useful D-allose derivatives

D-Allose and its derivatives play important roles in the field of health care and food nutrition. Pure and well-defined Dallose derivatives can facilitate the elucidation of their structure-activity relationship as an essential step for drug design. The LattrellDax epimerization, refers to the triflate inversion using nitrite reagent, is known as valuable method for the synthesis of rare D-allose derivatives. Here, the influence of protecting group patterns on the transformation efficiency of D-glucose derivatives into synthetically useful D-alloses and D-allosamines via the Lattrell-Dax epimerization was studied. For C3 epimerization of D-glucose derivatives bearing O2-acyl group, an anomeric configuration-dependent acyl migration from O2 to O3 was found. In addition, a neighbouring group participation effect-mediated SN1 nucleophilic substitution of the D-glucosamine bearing C2 trichloroacetamido(TCA) group in the Lattrell-Dax epimerization was dependent upon anomeric configuration. Thus, the effect of anomeric configuration on the LattrellDax epimerization of D-glucose suggests that β-D-glucosides with low steric hindrance at C2 should be better substrates for the synthesis of D-allose derivatives. Significantly, the efficient synthesis of the orthogonally protected D-allose 13 and D-allosamine 18 will serve well for further assembly of complex glycans.

Total synthesis of D-glycero-D-mannno-heptose 1β, 7-bisphosphate with 3-O-amyl amine linker and its monophosphate derivative

D-Glycero-D-mannno-heptose 1β,7-bisphosphate(HBPβ)is an important intermediate for constructing the core structure of Gram-negative bacterial lipopolysaccharides and was reported as a pathogen-associated molecular pattern(PAMP)that regulates immune responses.HBPβwith 3-O-amyl amine linker and its monophosphate derivative D-glycero-D-mannno-heptose 7-phosphate(HP)with 1α-amyl amine linker have been synthesized as candidates for immunity study of HBPβ.The O3-amyl amine linker of heptose was installed by dibutyltin oxide-mediated regioselective alkylation under fine-tuned protecting condition.The stereoselective installation of 1β-phosphate ester was achieved by NIS-mediated phosphorylation at low temperature.The strategy for installation of 3-O-amyl amine linker onto HBP derivative can be expanded to the syntheses of other conjugation-ready carbohydrates bearing anomeric phosphoester.

Determination of ribose and phosphorus contents in Haemophilus influenzae type b capsular polysaccharide by a quantitative NMR method using a single internal standard

The ribose and phosphorus contents in Haemophilus influenzae type b(Hib)capsular polysaccharide(CPS)are two important chemical indexes for the development and quality control of Hib conjugate vaccine.A quantitative ^(1)H-and ^(31)P-NMR method using a single internal standard was developed for simultaneous determination of ribose and phosphorus contents in Hib CPS.Hexamethylphosphoramide(HMPA)was successfully utilized as an internal standard in quantitative ^(1)H-NMR method for ribose content determination.The ribose and phosphorus contents were found to be affected by the concentration of polysaccharide solution.Thus,15–20 mg·L^(−1) was the optimal concentration range of Hib CPS in D_(2)O solution for determination of ribose and phosphorus contents by this method.The ribose and phosphorus contents obtained by the quantitative NMR were consistent with those obtained by traditional chemical methods.In conclusion,this quantitative ^(1)H-and ^(31)P-NMR method using a single internal standard shows good specificity,accuracy and precision,providing a valuable approach for the quality control of Hib glycoconjugate vaccines.

Chemical synthesis of a synthetically useful L-galactosaminuronic acid building block

Most bacterial cell surface glycans are structurally unique, and have been considered as ideal target molecules for the developments of detection and diagnosis techniques, as well as vaccines. Chemical synthesis has been a promising approach to prepare well-defined oligosaccharides, facilitating the structure-activity relationship exploration and biomedical applications of bacterial glycans. L-Galactosaminuronic acid is a rare sugar that has been only found in cell surface glycans of gram-negative bacteria. Here, an orthogonally protected L-galactosaminuronic acid building block was designed and chemically synthesized. A synthetic strategy based on glycal addition and TEMPO/BAIB-mediated C6 oxidation served well for the transformation of commercial L-galactose to the corresponding L-galactosaminuronic acid. Notably, the C6 oxidation of the allyl glycoside was more efficient than that of the selenoglycoside. In addition, a balance between the formation of allyl glycoside and the recovery of selenoglycoside was essential to improve efficiency of the NIS/TfOH-catalyzed allylation. This synthetically useful L-galactosaminuronic acid building block will provide a basis for the syntheses of complex bacterial glycans.

Chemical approaches towards installation of rare functional groups in bacterial surface glycans

Bacterial surface glycans perform a diverse and important set of biological roles,and have been widely used in the treatment of bacterial infectious diseases.The majority of bacterial surface glycans are decorated with diverse rare functional groups,including amido,acetamidino,carboxamido and pyruvate groups.These functional groups are thought to be important constituents for the biological activities of glycans.Chemical synthesis of glycans bearing these functional groups or their variants is essential for the investigation of structure-activity relationships by a medicinal chemistry approach.To date,a broad choice of synthetic methods is available for targeting the different rare functional groups in bacterial surface glycans.This article reviews the structures of naturally occurring rare functional groups in bacterial surface glycans,and the chemical methods used for installation of these groups.