多粘菌素B研究进展

多粘菌素B是经发酵产生的高分子十肽抗生素,由于其毒性大,在1970—1980年的临床应用几乎停止。近年来,在重症监护病房出现了多重抗体的耐药性革兰氏阴性细菌菌株,在没有新的抗菌剂能有效对抗这些病原体的情况下,有必要重新开展对多粘菌素B的研究。介绍了多粘菌素B的结构、特性、作用机制及生产方法等,提出随着合理给药方案的确立以及对毒性的进一步研究,多粘菌素B将迎来更为广阔的发展空间。     

微萃取器在多粘菌素B萃取工艺中的应用

利用微型化技术开发一种连续萃取多粘菌素B的工艺.通过对多级串联微萃取器萃取工艺中分散模块微孔尺寸、流体在微萃取器通道中的流速、串联级数和每级溶剂加量比例等关键控制参数的优化,取得了较好的实验结果.该工艺在萃取率、生产效率和溶剂消耗等方面较传统搅拌法萃取具有明显优势,操作用时短,重复性、稳定性、耐用性良好,且操作简单,可...     

多粘菌素E发酵工艺研究

本文研究了温度、溶氧、生物素、磷酸盐及PH对多粘菌素E发酵的影响。结果表明在控制培养温度34℃,溶氧40%以上的条件下,采用补料和自动控制PH工艺,可明显提高发酵效价,从480000u/ml提高到650000u/ml。     

血液净化用内毒素亲和吸附剂的制备研究

采用高碘酸钠法,以琼脂糖凝胶微球为载体,多粘菌素B(Polymyxin B,PMB)为配基,合成了血液净化用内毒素吸附剂,探讨了高碘酸钠的反应浓度、反应时间、反应温度对载体活化的影响,以及PMB的反应浓度、反应时间对偶联的影响,并对最优条件下合成的高分子吸附剂进行血浆中细菌内毒素的亲和性能评价。结果表明:琼脂糖活化时Na IO4的浓度为0.2 M、反应时间为4 h、反应温度为37℃时醛基含量达到最高值112.0μmol/g;配基偶联时PMB浓度为20 mg/mL、反应时间为4 h时配基偶联量达到最高值17.5 mg/g,静态吸附实验表明每毫升吸附剂填料对血浆中内毒素的吸附容量为71.7 EU,清除率为71.7%,表明该最优条件下合成出的吸附剂对血浆中细菌内毒素具有高选择性,高吸附容量。     

多粘菌素E高产菌株的推理选育

根据多粘菌素E生物合成途径进行高产菌株的推理选育.以多粘类芽孢杆菌(Bacillus polymgxa)C105x为出发菌株,采用紫外线诱变处理,并结合2,4-二氨基丁酸(L-DAB)和2-脱氧-D-葡萄糖(2-DOG)的抗性筛选,选育得到较佳正变株CL7-49.该菌株具有多粘菌素E发酵效价高、遗传稳定性好等特性.将该突变株应用于50 m3发酵罐的生产验证,发酵效价较对照菌株C105x提高了48%.     

杜仲中环烯醚萜类化合物的快速制备色谱制备及反相高效液相色谱/核磁共振鉴定

建立了杜仲中环烯醚萜类化合物京尼平甙酸(GPA)和京尼平甙(GPS)的快速制备色谱制备及反相高效液相色谱/核磁共振(RP-HPLC/NMR)鉴定方法。杜仲皮醇提物用硅胶柱层析法纯化后,进行快速制备液相色谱分离,根据制备色谱图收集流出液,采用HPLC-PDA和核磁共振(NMR)法定性定量分析。制备色谱条件为:流动相,V(甲醇)∶V(水)∶V(乙酸)=40∶60∶0.5;流速,2.5 mL/m in;检测波长,254 nm;进样体积,2.5 mL;进样量,100 mg;柱温,室温。结果表明,RP-HPLC分析制得产品的质量分数分别为w(GPA)=94.69%和w(GPS)=93.27%,核磁共振法测定结果与文献报道一致,确定实验所得两种单体为京尼平甙酸和京尼平甙。     

基于高效液相色谱法研究铜仁地区丹参中丹酚酸B的含量

目的:基于高效液相色谱法对铜仁地区丹参中的丹酚酸B含量进行探究。方法:采用Hubble C 18色谱柱(200 mm×4.6 mm,5μm),以V(乙腈)∶V(0.1%磷酸溶液)=22∶78为流动相进行洗脱,流速为1.2 m L/min。波长为286 nm;柱温为20℃;,检测波长为270nm,柱温为25℃。结果:通过实验证明其精密度、线性、重复性和稳定性均良好,显示该分析方法可行有效。结论:铜仁各产地丹参中丹酚酸B含量均符合国家标准,铜仁地区环境适应于丹参的生长栽培。     

异丙基罗丹明B酯的合成

以二氯亚砜（SOCl2）为催化剂,通过罗丹明B和异丙醇反应合成了异丙罗丹明B酯.在实验过程中,采用簿层色谱对反应进行跟踪,研究了反应温度和反应时间等因素对罗丹明B酯化速度和转化率的影响,确定了较佳的反应条件：催化剂为SOCl2,反应温度为70℃、反应时间为7 h.采用柱层析分离,展开剂为C2H5OH/CH2Cl2=2：1（体积比）.经过此法合成、提纯的异丙罗丹明B酯的纯度达到98.2%,总收率达到83%.     

B/Ti薄膜点火元件电爆输出性能研究

在Cu微桥箔基础上,利用电泳技术沉积B/Ti含能薄膜材料制备了点火元件。针对B/Ti含能薄膜材料,通过SEM和DSC开展了表面形貌和放热性研究。B/Ti含能薄膜材料颜色均匀,整体呈蓬松状,反应起始温度远低于B和Ti的熔点,且只有一个放热峰。对Cu/B/Ti点火元件进行了电学性能测试,输入电压400V的条件下,Cu/B/Ti电爆炸点火元件爆发时间为40ns,并伴有强烈的火光,火焰高度达数毫米。     

制备型高效液相色谱法分离冬凌草中冬凌草甲素

采用反相高效液相色谱技术,分离制备冬凌草中冬凌草甲素。制备色谱条件:色谱柱(80 mm i.d×500mm,μBondapakTMC18,粒径25~40μm);柱温:40℃;流动相:V(CH3OH)∶V(H2O)=50∶50;流速60 mL/min;检测波长239 nm;进样体积10 mL。将所收集16~23 min的洗脱液经蒸发浓缩,真空干燥,得冬凌草甲素白色粉末。160 g冬凌草可提取出500 mg冬凌草甲素(质量分数>99.0%)。采用质谱、元素分析、紫外、红外、核磁共振氢谱和高效液相色谱方法,鉴定和验证了提取物的结构。     

2-Aminobenzothiazoles Inhibit Virulence Gene Expression and Block Polymyxin Resistance in Salmonella enterica

One promising strategy to combat antibiotic-resistant bacteria is to develop compounds that block bacterial defenses against antibacterial conditions produced by the innate immune system. Salmonella enterica, which causes food-borne gastroenteritis and typhoid fever, requires histidine kinases (HKs) to resist innate immune defenses such as cationic antimicrobial peptides (CAMPs). Herein, we report that 2-aminobenzothiazoles block histidine kinase-dependent phenotypes in Salmonella enterica serotype Typhimurium. We found that 2-aminobenzothiazoles inhibited growth under low Mg²⁺, a stressful condition that requires histidine kinase-mediated responses, and decreased expression of the virulence genes pagC and pagK. Furthermore, we discovered that 2-aminobenzothiazoles weaken Salmonella’s resistance to polymyxin B and polymyxin E, which are last-line antibiotics and models for host defense CAMPs. These findings raise the possibilities that 2-aminobenzothiazoles can block HK-mediated bacterial defenses and can be used in combination with polymyxins to treat infections caused by Salmonella.     

制备型高速逆流色谱分离纯化北豆根中的生物碱类化合物

采用制备型高速逆流色谱仪TBE-300A分离纯化北豆根药材中的活性生物碱类化合物。在实验过程中对溶剂系统和参数条件进行了系统的优化,获得较好的分离条件：溶剂系统为石油醚-乙酸乙酯-乙醇-水（1：2：1：2,V／V／V／V）,上相（有机相）为固定相,下相（水相）为流动相,反相模式洗脱;进样浓度20mg／ml;进样体积20ml;流速2．0ml／min;转速850r／min。通过一步分离,获得了四种高纯度的生物碱类化合物,经HPLC、MS和NMR鉴定,分别为蝙蝠葛苏林碱（101．47mg,96．79／6）,蝙蝠葛碱（155．68mg,95．6％）,蝙蝠葛诺林碱（（25．4mg,96．2％）,蝙蝠葛新苛林碱（10．2mg,97．8％）。     

Hybrid Nanoparticles and Composite Hydrogel Systems for Delivery of Peptide Antibiotics

The growing number of drug-resistant pathogenic bacteria poses a global threat to human health. For this reason, the search for ways to enhance the antibacterial activity of existing antibiotics is now an urgent medical task. The aim of this study was to develop novel delivery systems for polymyxins to improve their antimicrobial properties against various infections. For this, hybrid core–shell nanoparticles, consisting of silver core and a poly(glutamic acid) shell capable of polymyxin binding, were developed and carefully investigated. Characterization of the hybrid nanoparticles revealed a hydrodynamic diameter of approximately 100 nm and a negative electrokinetic potential. The nanoparticles demonstrated a lack of cytotoxicity, a low uptake by macrophages, and their own antimicrobial activity. Drug loading and loading efficacy were determined for both polymyxin B and E, and the maximal loaded value with an appropriate size of the delivery systems was 450 µg/mg of nanoparticles. Composite materials based on agarose hydrogel were prepared, containing both the loaded hybrid systems and free antibiotics. The features of polymyxin release from the hybrid nanoparticles and the composite materials were studied, and the mechanisms of release were analyzed using different theoretical models. The antibacterial activity against Pseudomonas aeruginosa was evaluated for both the polymyxin hybrid and the composite delivery systems. All tested samples inhibited bacterial growth. The minimal inhibitory concentrations of the polymyxin B hybrid delivery system demonstrated a synergistic effect when compared with either the antibiotic or the silver nanoparticles alone.     

HPLC法测定复方利血平片中氢氯噻嗪、硫酸双肼屈嗪、维生素B_1和维生素B_6的含量

采用HPLC法测定复方利血平片中氢氯噻嗪、硫酸双肼屈嗪、维生素B1和维生素B6的含量。Kromasil C-18色谱柱（250 mm×4.6 mm,5μm）,检测波长210 nm,以0.2%己烷磺酸钠（用冰醋酸调节pH=3.5）-甲醇-乙腈（75∶20∶5）为流动相,流速1.0 mL/min,进样量20μL,柱温30℃。结果表明,氢氯噻嗪的线性范围为49.6～496.0μg/mL（R2=0.999 4）,精密度RSD为0.12%（n=6）,重复性RSD为0.45%（n=6）,平均回收率为99.74%（RSD=0.78%,n=9）;硫酸双肼屈嗪的线性范围为16.8～336.0μg/mL（R2=0.999 3）,精密度RSD为0.06%（n=6）,重复性RSD为0.21%（n=6）,平均回收率为99.83%（RSD=0.08%,n=9）;维生素B1的线性范围为4.0～80.0μg/mL（R2=0.998 7）,精密度RSD为0.56%（n=6）,重复性RSD为0.96%（n=6）,平均回收率为99.02%（RSD=1.13%,n=9）;维生素B6的线性范围为4.0～80.0μg/mL（R2=0.999 1）,精密度RSD为0.23%（n=6）,重复性RSD为0.78%（n=6）,平均回收率为99.56%（RSD=0.48%,n=9）。此法分离度好,峰形对称,分析周期短,重复性好,简单易行,可同时测定复方利血平片中氢氯噻嗪、硫酸双肼屈嗪、维生素B1和维生素B6的含量。     

高速逆流色谱分离纯化合成的和厚朴酚抗肿瘤衍生物

首次采用高速逆流色谱对合成的和厚朴酚生物进行分离纯化。本实验首先通过Reiman—Tie—mann反应将和厚朴酚甲酰化,再与盐酸羟胺生成3个和厚朴酚的衍生物,然后通过HSCCC将它们分离纯化。分离过程,我们对溶剂体系和样品浓度以及进样速度等参数条件进行了优化,获得了较好的分离。溶剂体系为正己烷-乙酸乙酯-甲醇-水（1：0．4：1：0．4,V／V）,下相作为固定相,进样浓度为20mg／ml,进样体积为20ml,流速设定为2ml／min,转速为850rpm。分离产物经MS和NMR结构鉴定。     

Stimulation of rat liver mitochondrial <Emphasis Type="Italic">sn</Emphasis>-glycerol-3-phosphate acyltrasferase by polymyxin B <Emphasis Type="Italic">via</Emphasis> enhanced extraction of lysophosphatidic acid

The purpose of this investigation was to determine how polymyxin B stimulates the activity of mitochondrial glycerophosphate acyltransferase. Polymyxin B did not change the integrity of the mitochondrial outer membrane as judged by testing the latency (>80%) of cytochrome oxidase activity. The stimulation totally disappeared when polymyxin B-treated mitochondria were washed. The FA side chain in polymyxin B was unnecessary for stimulation, as the nonapeptide was as effective as the whole antibiotic. The stimulation by polymyxin B or the nonapeptide was observed only in the presence of BSA. Cytochrome c, when added to the incubation medium instead of albumin, did not stimulate the mitochondrial enzyme, but did produce a stimulatory effect of polymyxin B on the mitochondrial acyltransferase. As reported earlier for the bacterial and microsomal acyltransferase, other polycationic compounds such as spermine and spermidine stimulated mitochondrial glycerophosphate acyltransferase. The stimulation of the mitochondrial acyltransferase by spermine and spermidine also occurred only in the presence of BSA. The analysis of the products of esterification demonstrated the presence of more lysophosphatidic acid (LPA) in the polymyxin B-and polyamine-stimulated assays in comparison to their respective control. Furthermore, in comparison to the albumin-treated control, there was 60% more LPA present in the assay supernatant fractions of polymyxin B-treated samples. Our results suggest that polymyxin B stimulates the mitochondrial glycerophosphate acyltransferase activity by enhancing the extraction of more LPA from the mitochondria to the supernatant fraction.     

高效液相色谱法测定亳芍中芍药苷的含量研究

建立亳芍中芍药苷含量的HPLC测定方法。方法:采用岛津VP-ODS C18色谱柱(5μm,250mm×4.6mm),流动相为0.1%磷酸溶液-乙腈(80∶20,V/V),流速为1.0mL/min,检测波长为230nm,柱温为室温。结果:在0.028mg/mL～0.142mg/mL范围内芍药苷的量与其峰面积呈良好的线性关系,平均加样回收率为98.3%。结论:采用HPLC测定亳芍中芍药苷的含量简便、准确、选择性好,可用于亳芍中芍药苷的含量测定。     

Comparison of Two Solvent Extraction Systems for the Separation of V(V) and Cr(VI) from an Industrial Leaching Solution

Two solvent extraction systems for V (V) and Cr (VI) separation in leaching solution were investigated in order to select the suitable separation method for the disposing of chromium-bearing vanadium slag. The best/suitable system was determined by extraction yield (E_V，%) and the separation factor of V(V) and Cr(VI) (β_V/Cr). On the condition of 1:1 molar ratio of H⁺ to vanadium (V), the E_V values were 99.8% and 95.1%, while the β_V/Cr values were 546.58 and 29.53 using the two different systems, respectively. The extraction reactions for system 1 were determined by the slope method, and the chemical equilibrium constants were obtained.