三种兽药添加剂对土壤赤子爱胜蚓的毒理学研究

喹乙醇、阿散酸和土霉素是应用极广的兽药添加剂,在畜牧业的发展中起着特殊的作用,但其使用不当或过量使用会给环境带来很大危害.采用土壤中的重要生物赤子爱胜蚓作为生物材料,分别研究了喹乙醇、阿散酸和土霉素对赤子爱胜蚓的急性毒性和对赤子爱胜蚓体腔细胞DNA的损伤.结果表明,喹乙醇溶液法LC₅₀>2000mg·L^-1,滤纸法LC₅₀>5.71×10^-2mg·cm^-2,而阿散酸和土霉素在所设最大受试剂量内没有毒性.单细胞凝胶电泳试验结果表明,阿散酸没有引起蚯蚓体腔细胞DNA明显损伤;喹乙醇和土霉素均能引起一定程度的DNA损伤,中、高剂量组与阴性对照相比有极显著差异(P<0.01).因此,有必要加强对以上兽药添加剂,特别是喹乙醇和土霉素的管理,控制用药时间和剂量,以确保人体健康和环境安全.     

几种抗生素对白蚁的实验室毒力测定

本试验利用金霉素、四环素、土霉素等3种抗生素对南京地区5种低等白蚁进行实验室毒力测定．试验采用“强迫取食”和“暂时强迫取食”两种方法。以各供试白蚁种对3种抗生素的每个含药梯度进行毒力测定．结果表明．盐酸金霉素对各供试白蚁肠内原生动物的毒力最强．盐酸四环素次之。盐酸土霉素最差．因而盐酸金霉素可在杀白蚁剂中用作酸方的有效成分．     

土霉素残留对蔬菜发酵过程微生物群落演替及代谢产物的影响

【目的】探究土霉素残留对蔬菜自然发酵过程中微生物群落演替和代谢产物动力学的影响,为评估抗生素残留对蔬菜发酵的影响提供理论基础。【方法】超高效液相色谱-串联质谱法测定土霉素残留;高效液相色谱法测定有机酸、电子鼻和气相色谱-质谱联用测定挥发性成分和高通量技术测定微生物种类。【结果】蔬菜自然发酵过程中,土霉素残留从4.00 mg/L下降到2.53 mg/L;不含抗生素残留的蔬菜发酵含有同型和异型乳酸发酵,而土霉素残留的蔬菜发酵仅含有同型乳酸发酵;同时,其特征微生物由Lactobacillus pentosus和Lactobacillus plantarum转变为Lactobacillus paratarrginis、Lactobacillus buchneri和Lactobacillus kisonensis;土霉素残留明显影响了乳酸、柠檬酸、乙酸、香茅醇、3-辛醇、异硫氰酸烯丙酯、乙酸香叶酯、乙烯基硬脂醚和异硫氰酸苯乙酯等代谢产物的含量。【结论】土霉素残留影响了蔬菜乳酸发酵的类型、微生物群落的演替、有机酸和挥发性化合物的形成过程,因此应将抗生素残留纳入发酵蔬菜原料的质量控制指标。     

4种市售抗生素对发酵床垫料中益生微生物生长的影响

目的研究不同剂量土霉素、盐酸环丙沙星、克拉霉素、乙酰甲喹对垫料中益生微生物生长的影响。方法以饲料中抗生素添加量、抗生素在动物体内转化率为依据,观察0.1×国标、1×国标和10×国标对应的抗生素残留对垫料中主要益生微生物生长的影响。结果与空白组相比,0.1×国标的土霉素和克拉霉素残留对3种益生微生物影响小,盐酸环丙沙星和乙酰甲喹残留使枯草芽胞杆菌和酵母菌数量不可检测;1×国标量的土霉素残留对3种益生微生物影响较小,而盐酸环丙沙星、克拉霉素、乙酰甲喹残留造成了益生微生物的不可检测;除植物乳杆菌在10×国标的土霉素残留中生长变化小外,所有检测菌在该浓度其他抗生素残留中均不可检测。结论土霉素、盐酸环丙沙星、克拉霉素、乙酰甲喹残留对垫料中主要益生微生物生长均有不同程度的影响。     

9种常用抗菌药物对肺炎克雷伯菌释放内毒素的影响

目的:探讨单用或联合使用不同浓度的抗菌药物诱导细菌释放内毒素能力,为临床合理选择抗生素提供依据。方法:研究中选择9中常用的抗菌药物以1倍、10倍和100倍MIC浓度进行单独或联合作用在肺炎克雷伯菌上,4小时后释放的毒素量。结果:单用或联用氨基糖苷类药物方案诱导细菌释放内毒素量较小;单用或联用氟喹诺酮类药物能够诱导中等量内毒释放,中,低浓度是释放内毒素量较大;单用B-内酰胺类药物诱导内毒素量相对比较大。低浓度比高浓度的抗菌药物诱导细菌释放内毒素量更多(P0.05)。结论:革兰阴性杆菌感染发病率较高,临床上应该多参考诱导细菌释放内毒素的特性,为患者合理使用抗菌药物提供依据,降低药物耐药发生率。     

两种水生植物对抗生素污染水体的修复作用

采用水培方法,通过检测水样中氨苄青霉素（Ampicillin）、盐酸四环素（Tetracycline）、盐酸土霉素（Oxytetracycline）和盐酸金霉素（Chlortetracycline）含量的动态变化,确定水生植物大漂（Pistia stratiotes）和凤眼莲（Eichhornia crassipes）对水体中抗生素的清除作用。结果显示：①在系列高浓度（10～50 μg/mL）抗生素的条件下,凤眼莲去除水中盐酸金霉素与盐酸土霉素的效果优于大漂;②对于采集的污水（抗生素浓度＜2.5 μg/mL）,培养72 h后,大漂和凤眼莲对盐酸四环素的去除率分别达80%和90%以上,对氨苄青霉素的去除率分别达80%和70%以上。大漂和凤眼莲对4种抗生素污染的水体均表现出不同程度的修复功能,特别是凤眼莲效果更佳,可作为去除水体抗生素污染的首选材料。     

基于银纳米棒的表面增强拉曼基底探究土霉素对植物乳杆菌的影响

【背景】土霉素属四环素类抗生素,在医疗制药和动物养殖行业应用广泛。抗生素的滥用与残留极易导致环境中的益生菌产生耐药,各类益生菌通过食物进入机体后,可将耐药基因转移给致病菌。目前的耐药菌株筛选方法耗时较长,最小抑菌浓度测定结果也可能存在偏差,而且无法在抗菌机理及耐药机制方面提供线索。【目的】采用表面增强拉曼光谱（surface enhanced Raman spectroscopy,SERS）技术探究土霉素与植物乳杆菌之间的相互作用,以期为微生物耐药菌株的快速筛选提供理论基础,并为研究抗菌机理及耐药机制提供思路及方法。【方法】组装银纳米棒与石英后得到一种具有良好、稳定的SERS增强效应的固相基底;在植物乳杆菌菌液中加入不同浓度土霉素后各自分别孵育30、60和90 min,利用组装好的固相基底对细菌细胞进行SERS信号测定,拉曼光谱的出峰位置和峰强度变化可以体现不同土霉素浓度及作用时间条件下植物乳杆菌细胞成分的差异,可进一步推断土霉素对植物乳杆菌生长的影响。【结果】0.5×MIC土霉素会造成SERS光谱强度的降低;1.0×MIC土霉素作用90 min后,SERS在1 612、1 630 c...     

临床药学参与抗生素药物应用管理在重症感染中的作用

目的探讨临床药师参与重症感染抗生素应用的指导作用。方法选取2016年1月~2017年8月在我院ICU的重症感染患者500例,按是否请临床药学指导抗生素使用进行分为研究组263例和对照组237例,比较两组患者抗菌药物联合用药、降阶梯治疗天数、使用疗程以及继发二重感染、住ICU时间、感染相关的病死率情况。结果两组患者的抗菌药物使用情况比较,差异有统计学意义(均P0.01)。研究组抗菌药物单用和二联用均较对照组高,三联及以上联用较对照组低(均P0.01)。研究组降阶梯治疗天数、使用疗程以及继发二重感染、住ICU时间、感染相关的病死率均较对照组低(均P0.05)。结论临床药学参与重症感染的抗生素使用指导有助于促进抗生素的合理应用,提高治疗效果。     

六种常见抗生素对小白菜种子萌发及生理特性的影响

以小白菜为受试生物,研究了6种常用抗生素(四环素、土霉素、金霉素、强力霉素、氯霉素和磺胺二甲嘧啶)对小白菜种子萌发、根(芽)伸长、可溶性蛋白及抗氧化酶系统的毒理效应。结果表明,0.5~5 mg·L-1抗生素胁迫下,小白菜种子的发芽率无显著变化,随着抗生素暴露浓度的增加,小白菜种子的发芽率受到了显著抑制;抗生素暴露浓度与小白菜根(芽)伸长抑制率之间具有良好的剂量效应关系。由抗生素对小白菜根长的半抑制效应浓度(EC50)可知,6种抗生素对小白菜种子萌发的毒性大小依次为:磺胺二甲嘧啶氯霉素金霉素四环素强力霉素土霉素。实验浓度范围内的抗生素对小白菜幼苗体内可溶性蛋白含量具有显著的诱导效应,且各处理组间差异显著。此外,抗生素的胁迫破坏了小白菜幼苗体内的抗氧化防御系统的平衡。     

稀土抗菌效应及应用的研究进展

稀土元素具有多种生物效应, 除了对农作物的增产作用外, 在医药方面还具有抗菌的作用, 近年来, 不少学者针对稀土元素的抗菌效应展开了相关的研究。本文介绍了稀土在抗菌领域的研究及应用, 包括稀土化合物对微生物生长的Hormesis效应、稀土化合物与抗生素的协同作用、稀土配合物的合成、以及稀土在抗菌材料上的应用等几个方面的内容, 并对稀土化合物及其配合物的抗菌机理进行了探讨, 最后, 展望了稀土化合物及配合物在抗菌领域的应用前景及研究重要性。     

桂皮酸-8-羟基喹啉稀土配合物的合成、抑菌活性及其对DNA的作用

以稀土离子为模板,用桂皮酸、8-羟基喹啉为原料,在乙醇溶液中首次合成了两种稀土三元配合物,采用元素分析、摩尔电导、红外光谱、紫外光谱和荧光光谱进行表征,并研究了配合物对常见细菌大肠杆菌和金黄色葡萄球菌的抑菌活性以及与DNA的相互作用.结果表明:配合物的抑菌活性较配体和稀土离子均有提高,能使细胞正常的DNA复制生理功能受到影响.     

Bio-Synthesis of Gold Nanoparticles by <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> and Assessment of Their Conjugation Possibility with Two Types of β-Lactam Antibiotics without Any Additional Linkers

In the present study, biosynthesis of gold nanoparticles (GNPs) by Fusarium oxysporum was carried out and their conjugation possibility with two β-lactam antibiotics was evaluated. F. oxysporum was cultured and the fungal culture supernatant was subjected to the 1 mmol final concentration of chloroauric acid solution. The produced GNPs were analyzed using visible spectrophotometer, X-ray diffraction analysis (XRD) and transmission electron microscope (TEM). After the purification of GNPs, they were subjected to penicillin G and ceftriaxone without any additional linkers. Finally, the mixture was analyzed using visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and TEM and subjected to antibacterial activity test using the well diffusion method. Results confirmed the presence of GNPs in the F. oxysporum culture supernatant after the addition of chloroauric acid. TEM results showed that GNPs were spherical and amorphous with sizes around 10–25 nm and XRD confirmed the presence of GNPs in the fungal culture supernatant. After the incubation of GNPs with the antibiotics, FTIR results demonstrated the successful linking of GNPs with the corresponded antibiotics and TEM images showed that GNPs sizes were bigger than the pure ones (around 50–100 nm). Finally the antibacterial activity test indicated that absolutely, the antibacterial properties of the GNPs-β-lactam antibiotics was lowered or not changed in contrast to the pure antibiotics. The present study showed that GNPs had high tendency of conjugation with antibiotics but unlike the previous researches, linking of the antibiotics to GNPs always cannot improve their antibacterial activity based on the antibiotics that were used. The high conjugation affinity of GNPs made them a good candidate as detoxification agent in diverse areas of medicine or environmental sciences.     

脂肽类抗生素及其作用机制

脂肽类抗生素是由微生物代谢产生的一类具有很强表面活性的生物活性物质,含有由亲水性氨基酸和疏水性脂肪酸链组成的特殊分子结构,表现出亲水、亲脂两亲性的特性,具有抗菌、抗肿瘤和抗病毒等多种生物学活性,作为抗菌药物和肿瘤抑制剂在医药和临床应用领域具有良好的应用潜力和前景。本文对脂肽类抗生素的结构、生物学功能和作用机制等最新研究进展进行综述。     

几种中药单体和抗生素对嗜水气单胞菌及温和气单胞菌的体外抑菌活性研究

考察没食子酸等6种中药单体和诺氟沙星等3种抗生素对嗜水气单胞菌及温和气单胞菌的体外抑菌活性及其联合抑菌作用。通过琼脂扩散法测定受试物的抑菌作用,用微量二倍稀释法测定受试物最小抑菌浓度（MIC）和最小杀菌浓度（MBC）,用棋盘法考察受试物的联合抑菌作用。6种中药单体中没食子酸和槲皮素对嗜水气单胞菌及温和气单胞菌抑制作用较强,抑菌圈均达到20 mm以上,没食子酸对嗜水气单胞菌及温和气单胞菌的MIC和MBC均为250 g/mL;槲皮素对嗜水气单胞菌的MIC和MBC均为500 g/mL,对温和气单胞菌的MIC和MBC分别为250和500 g/mL;而大黄素甲醚等4种中药单体无明显的抑菌作用。嗜水气单胞菌及温和气单胞菌对诺氟沙星、恩诺沙星、氟苯尼考等抗生素均极敏感。在联合药敏试验中,没食子酸与恩诺沙星或氟苯尼考、槲皮素与氟苯尼考联合用药对嗜水气单胞菌具有相加抑菌作用;没食子酸与恩诺沙星联合用药对温和气单胞菌具有协同抑菌作用,没食子酸与诺氟沙星或氟苯尼考、槲皮素与氟苯尼考联合用药对温和气单胞菌具有相加抑菌作用。没食子酸和槲皮素对嗜水气单胞菌及温和气单胞菌具有显著的抑制作用,二者与恩诺沙星、诺氟沙星、氟苯尼考等抗生素联合应用具有相加或协同作用,有助于降低抗生素的用量及残留。       

Arsenic Uptake and Accumulation in Rice (Oryza sativa L.) at Different Growth Stages following Soil Incorporation of Roxarsone and Arsanilic Acid

Experiments were conducted with rice (Oryza sativa L.) by adding 0, 10, 20, 30, 40, 50 mg kg^-1 of arsenic (As) to soil (with roxarsone and arsanilic acid, presented as As concentrations) at a field with an isolation chamber. The aims were to evaluate the effects of As- (roxarsone or arsanilic acid) contaminated soil on rice agronomic parameters and uptake of As in different plant parts of the rice plant. The results showed that As (roxarsone or arsanilic acid) could significantly reduce plant height, effective tiller number, straw weight and grain yield (P < 0.01). As concentrations in different parts of the plant varied with the growth stages, and behaved similarly. At the maturing stage, the level in different parts peaked in all treatments, with tissue As concentrations showing the pattern: root > leaf > stem > husk > grain. In addition, at the mature stage, the As concentrations in different parts of the rice plant increased with increasing concentrations of roxarsone and arsanilic acid. The highest concentration of As found in grain was 0.82 mg kg^-1, which did not exceed the statutory permissible limit for rice grain (1.0 mg As kg^-1), and in the leaf and stem it was approximately 6.0 mg kg^-1, which was significantly higher than that in the controls. The results showed that rice could accumulate As from contaminated soil (roxarsone or arsanilic acid), which may be transferred to human beings via the food chain.     

Undecaprenyl Pyrophosphate Involvement in Susceptibility of Bacillus subtilis to Rare Earth Elements

The rare earth element scandium has weak antibacterial potency. We identified a mutation responsible for a scandium-resistant phenotype in Bacillus subtilis. This mutation was found within the uppS gene, which encodes undecaprenyl pyrophosphate synthase, and designated uppS86 (for the Thr-to-Ile amino acid substitution at residue 86 of undecaprenyl pyrophosphate synthase). The uppS86 mutation also gave rise to increased resistance to bacitracin, which prevents cell wall synthesis by inhibiting the dephosphorylation of undecaprenyl pyrophosphate, in addition to enhanced amylase production. Conversely, overexpression of the wild-type uppS gene resulted in increased susceptibilities to both scandium and bacitracin. Moreover, the mutant lacking undecaprenyl pyrophosphate phosphatase (BcrC) showed increased susceptibility to all rare earth elements tested. These results suggest that the accumulation of undecaprenyl pyrophosphate renders cells more susceptible to rare earth elements. The availability of undecaprenyl pyrophosphate may be an important determinant for susceptibility to rare earth elements, such as scandium.     

具有优良抑菌特性乳酸菌的筛选鉴定及活性物质检测

【背景】有益性乳酸菌在人体和动物体内分布极为广泛,是维持胃肠道菌群平衡、提高机体免疫力的主力军。近年来,为了解决禁用抗生素而导致动物发病率不断增高的问题,分析和研究乳酸菌及其所产活性物质的益生特性并开发新型饲料添加剂成为一个重要手段。【目的】本实验旨在从土壤中分离筛选出具有优良抑菌特性的乳酸菌,并对其所产活性物质的特性进行分析评价。【方法】采用溴甲酚紫平板法筛选并结合抑菌能力检测,得到2株具有优良抑菌特性的产酸菌株,分别命名为H-3和H-4。经形态学鉴定及16S rRNA基因序列测定后,对2株菌分别进行生长曲线和产酸量检测;通过排除酸处理、蛋白酶处理和热处理的方法分析2株菌所产抑菌物质的有效成分。【结果】H-3和H-4菌株经初步鉴定为乳酸片球菌(Pediococcus acidilactici),2株菌均具有良好的生长性能及产酸性能。菌株发酵上清液对大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、猪霍乱沙门氏菌(Salmonella choleraesuis)、福氏志贺氏菌(Shigella flexneri)均表现出明显的抑...     

家蝇幼虫抗菌肽的抗菌谱及其与抗生素的协同作用研究

研究3种家蝇幼虫抗菌肽的抗菌谱以及每种抗菌肽的最小抑菌浓度(MIC),初步探讨3种抗菌肽分别与青霉素、链霉素相结合后对抗菌活性的影响,并采用分级抑制浓度指数(Fractionalinhibitoryconcentrationindex,FIC)来定量检测抗菌肽与抗生素之间的抗菌作用关系。结果表明3种抗菌肽的抗菌谱不同,不同的抗菌肽对不同病原菌的抗菌活性不同。3种抗菌肽与链霉素、青霉素之间的抗菌协同关系因细菌种类不同。抗菌肽与抗生素之间并不是都存在协同关系,有些不相关,甚至表现为对抗关系,表明抗菌肽、抗生素与细菌三者的相互作用关系非常复杂。     

Hepatitis C patients in puerto rico have an altered iron balance

The in vivo coordination structure of lanthanum ions interacting with chlorophyll-a of the fern Dicranopteris dichotoma grown in a rare earth minefield in southern China was determined by the extended x-ray absorption fine structure (EXAFS). The results show that lanthanum includes two porphyrin rings in its coordination sphere. It is postulated that the La-chlorophyll-a complex may have a bilayer structure. The analytical method may serve as a new tool to gain insight in the in vivo interactions of rare earth elements.     

酸雨胁迫下,稀土元素对菠菜膜保护系统作用

利用盆栽实验,探讨了酸雨胁迫下对菠菜膜保护酶系统的防护效应,实验结果表明,单一酸雨处理会造成超氧化物歧化酶（ＳＯＤ）,过氧化酶（ＣＡＴ）活性总体水平下降,其变化曲线呈“Ａ”形,并使过氧化物酶（ＰＯＤ）活性明显增加,施用稀土元素后酸雨胁迫下的植株叶片中ＳＯＤ,ＣＡＴ活性总体水平上升,变化曲线的峰值向酸度较大的方向移动,ＰＯＤ活性上升幅度减小,３种膜保护酶的活性与单一酸雨处理组相比,处在一种结稳定的状