疟疾疫苗的研究现状和难度

疟疾疫苗的研究现状和难度朱艳琴综述（常州市卫生局２１３００３）叶炳辉审校（南京医科大学２１００２９）分类号Ｒ５３１．３疟原虫抗药性和蚊媒耐药性的产生和扩散,促使人们重新考虑发展安全有效的疫苗来控制疟疾,特别是淋巴细胞杂交瘤技术研究成功以后,对疟疾疫苗...     

昆虫对植物次生物质的代谢适应机制及其对昆虫抗药性的意义

植物次生物质(plant secondary metabolites)对昆虫的取食行为、生长发育及繁殖可以产生不利影响,甚至对昆虫可以产生毒杀作用。为了应对植物次生物质的不利影响,昆虫通过对植物次生物质忌避取食、解毒代谢等多种机制,而对寄主植物产生适应性。其中,昆虫的解毒代谢酶包括昆虫细胞色素P450酶系（P450s）及谷胱甘肽硫转移酶（GSTs）等,在昆虫对植物次生物质的解毒代谢及对寄主植物的适应性中发挥了重要作用。昆虫的解毒酶系统不仅可以代谢植物次生物质,还可能代谢化学杀虫剂,因而昆虫对寄主植物的适应性与其对杀虫剂的耐药性甚至抗药性密切相关。昆虫细胞色素P450s和GSTs等代谢解毒酶活性及相关基因的表达可以被植物次生物质影响,这不仅使昆虫对寄主植物的防御产生了适应性,还影响了昆虫对杀虫剂的解毒代谢,因而改变昆虫的耐药性或抗药性。掌握昆虫对植物次生物质的代谢适应机制及其在昆虫抗药性中的作用,对于明确昆虫的抗药性机制具有重要的参考意义。本文综述了植物次生物质对昆虫的影响、昆虫对寄主植物次生物质的代谢机制、昆虫对植物次生物质的代谢适应性对昆虫耐药性及抗药性的影响等方面的研究进展。     

细菌的应激反应和生理代谢与耐药性及其控制策略

抗菌药在医疗和畜牧生产中的滥用导致了细菌抗药性的产生,这个公共卫生问题引起了人们越来越多的关注。除了基因突变和获得形成的抗药性 (Resistance) 外,细菌在自然环境中遇到的各种压力会引发其产生应激反应,这不仅可以保护细菌免受这些压力的影响,还会改变细菌对抗菌药的耐药性 (Tolerance)。耐药性的产生必然会影响细菌的生理代谢,但是细菌可以通过调节自身代谢恢复对药物的敏感性。文中综述了近年来细菌应激反应和生理代谢与细菌耐药性之间的相关研究,以期采取更加有效的措施来控制细菌抗药性的发生和蔓延。     

肿瘤细胞抗药性的分子机理

肿瘤细胞抗药性的分子机理周剑涛（湖北省黄冈地区卫校,４３６１００）关键词肿瘤细胞,抗药性,分子机理化疗是治疗肿瘤的重要方法之一。但肿瘤细胞对化疗药物易产生抗药性,成为临床一大难题。近年来,对肿瘤细胞产生抗药性的分子机理进行了大量研究,并取得如下一些进...     

名词解释

抗药性亦称“耐药性”。生物对于药物的抵抗性。一般指对某一药物原来敏感的微生物或昆虫,经长期使用该一药物后所出现的抵抗力。例如有些葡萄球菌菌株已对青霉素产生了抗药性,有些蚊、蝇对滴滴涕产生了抗药性,在这种情况下,必须改用其他适当药物才能消灭它们。     

染色体介导的细菌耐药性与毒力

本文以鼠伤寒杆菌为例,扼要阐述了细菌染色体突变引起细菌产生抗生素耐药性的机理,并以绿脓杆菌和金黄色葡萄球菌（简称金葡菌）等为例讨论了染色体介导的耐药性与毒力的关系。     

植物病原真菌对二甲酰亚胺类杀菌剂的抗性分子机制

综述了近年来国内外植物病原真菌对二甲酰亚胺类杀菌剂抗性机制研究的主要成果,包括：二甲酰亚胺类杀菌剂（DCFs）的杀菌机制、植物病原菌对DCFs抗药性的产生现状、促分裂原活化蛋白激酶（MAPK）途径和依赖环化腺苷酸（cAMP）的蛋白激酶途径在抗药性产生中的可能作用及相关的分子生物学研究进展。     

卵巢肿瘤对化疗产生抗药性的一个可能原因

临床上,铂类化疗药物如顺铂（Cisplatin）和卡铂（Carboplatin）用于因肿瘤抑制因子BRCA2突变引起的卵巢癌患者的治疗。在治疗早期,这种方案的疗效是令人满意的。但大多数卵巢肿瘤患者逐渐都会对这种药物产生抗药性,从而负面影响最终的治疗效果。引起这种抗药性产生的确切原因一直并不清楚。     

昆虫抗药性靶标不敏感机制的研究进展

靶标不敏感（targetsiteinsensitivity）是昆虫对杀虫剂产生抗药性的一个极为重要的生化机制,已在多种昆虫对多种杀虫剂的抗性中发现[1,2],最著名的便是：变构乙酰胆碱酯酶（alteredacetvlcholinesterase,简称变构AChE）对有机磷和氨基甲酸酯类杀虫剂的抗性、不敏感的Na 通道（insensitivesodiumchannel）对DDT和除虫菊酯的击倒抗性（knockdownresistance,kdr）,以及不敏感的γ-氨基丁酸受体（insensitiveGABAreceptor）对环戊二烯类杀虫剂和γ-六六六的抗性[3]。80年代以来,众多学者利用各种技术尤其是分子生物学技术对上述靶…     

名词解释

耐药性病原微生物失去对某种药物(包括抗菌素)的敏感性,即增强了对药物的耐受能力,称之为耐药性或抗药性。耐药菌株的产生,有人认为有自发变异菌存在,敏感菌被杀死或受抑制后,自发变异体更容     

Impedimetric immunosensor doped with reduced graphene sheets fabricated by controllable electrodeposition for the non-labelled detection of bacteria

A facile, sensitive and reliable impedimetric immunosensor doped with reduced graphene sheets (RGSs) and combined with a controllable electrodeposition technique was developed for the selective detection of marine pathogenic sulphate-reducing bacteria (SRB). The morphology of RGSs and the electrochemical properties of RGSs-doped chitosan (CS) nanocomposite film were investigated by atomic force microscopy, Fourier transform infrared spectroscopy, and cyclic voltammetry (CV). Electrochemical impedance spectroscopy and CV were used to verify the stepwise assembly of the sensor system. Faradic impedance spectroscopy for charge transfer for the redox probe Fe(CN)(6)(3-/4-) was done to determine SRB concentrations. The diameter of the Nyquist diagram that is equal to the charge-transfer resistance (R(ct)) increased with increasing SRB concentration. A linear relationship between R(ct) and SRB concentration was obtained in the SRB concentration range of 1.8×10(1) to 1.8×10(7) cfu/ml. The impedimetric biosensor gave a distinct response to SRB, but had no obvious response to Vibrio angillarum. It showed a high selectivity for the detection of the pathogen. Based on a combination of the biocompatibility of CS and good electrical conductivity of RGSs, a nanocomposite film with novel architecture was used to immobilize biological and chemical targets and to develop a new type of biosensor.     

Impedimetric biosensor based on cell-mediated bioimprinted films for bacterial detection

This work presents the synthesis of bacteria-mediated bioimprinted films for selective bacterial detection. Marine pathogen sulfate-reducing bacteria (SRB) were chosen as the template bacteria. Chitosan (CS) doped with reduced graphene sheets (RGSs) was electrodeposited on an indium tin oxide electrode, and the resulting RGSs-CS hybrid film served as a platform for bacterial attachment. The electrodeposition conditions were optimized to obtain RGSs-CS hybrid films with excellent electrochemical performance. A layer of nonconductive CS film was deposited to embed the pathogen, and acetone was used to wash away the bacterial templates. Electrochemical impedance spectroscopy was performed to characterize the stepwise modification process and monitor the SRB population. Faradic impedance measurements revealed that the charge transfer resistance (R(ct)) increased with increased SRB concentration. A linear relationship between ΔR(ct) and the logarithm of SRB concentration was obtained within the concentration range of 1.0×10(4)cfumL(-1) to 1.0×10(8)cfumL(-1). The impedimetric sensor showed good selectivity towards SRB based on size and shape. Hence, selectivity for bacterial detection can be improved if the bioimprinting technique is combined with other bio-recognition elements.     

Sulphate reduction and vertical distribution of sulphate-reducing bacteria quantified by rRNA slot-blot hybridization in a coastal marine sediment

In the past, enumeration of sulphate-reducing bacteria (SRB) by cultivation-based methods generally contradicted measurements of sulphate reduction, suggesting unrealistically high respiration rates per cell. Here, we report evidence that quantification of SRB rRNA by slot-blot hybridization is a valuable tool for a more realistic assessment of SRB abundance in the natural environment. The distribution of SRB was investigated in a coastal marine sediment by hybridization of membrane-immobilized rRNA with oligonucleotide probes. As represented by general probe-target groups, SRB rRNA contributed between 18% and 25% to the prokaryotic rRNA pool. The dominant SRB were related to complete oxidizing genera (Desulphococcus, Desulphosarcina and Desulphobacterium), while Desulphobacter could not be detected. The vertical profile and quantity of rRNA from SRB was compared with sulphate reduction rates (SRR) measured with 35SO4(2-) tracer in whole-core incubations. While SRB abundance was highest near the surface, peaking at around 1.5 cm, measured sulphate reduction rates were lowest in this region. A second peak of SRB rRNA was observed at the transition zone from oxidized to reduced sediment, directly above the sulphate reduction maximum. Cell numbers calculated by converting the relative contribution of SRB rRNA to the percentage of DAPI-stained cells indicated a population size for SRB of 2.4-6.1 x 10(8) cells cm(-3) wet sediment. Cellular sulphate reduction rates calculated on the basis of these estimated cell numbers were between 0.01 and 0.09 fmol SO4(2-) cell(-1) day(-1), which is below the rates that have been determined for pure cultures (0.2-50 fmol SO4(2-) cell(-1) day(-1)) growing exponentially at nearoptimal temperature with a surplus of substrates.     

Evaluation of the sulfate-reducing bacterial population associated with stored swine slurry

Hydrogen sulfide, produced by sulfate-reducing bacteria (SRB), is one of the most potent malodors emitted from anaerobic swine waste storage systems. However, little is known about the prevalence and diversity of SRB in those systems. The goals of this study were to evaluate the SRB population in swine manure storage systems and to develop quantitative, real-time PCR (QRT-PCR) assays to target four of the SRB groups. Dissimilatory sulfite reductase (DSR) gene sequences were obtained from swine slurry stored in underground pits (43 clones) or in lagoons (34 clones). QRT-PCR assays were designed to target the dsrA gene of four novel groups of SRB. Sequences of dsrA clones from slurry samples grouped with those from three different cultured SRB: Desulfobulbus sp. (46 clones), Desulfovibrio sp. (24 clones and 5 isolates), and Desulfobacterium sp. (7 clones). However, DsrA sequences from swine slurry clones were generally less than 85% similar to those of cultured organisms. SRB from all four targeted SRB groups were detected in underground waste storage pits (6.6 x 10(3)-8.5 x 10(7) dsrA copies mL(-1) slurry), while only two groups of SRB were detected in lagoons (3.2 x 10(5)-2.5 x 10(6) dsrA copies mL(-1) slurry). To date, this is the only study to evaluate the phylogeny and concentration of SRB in any livestock waste storage system. The new QRT-PCR assays should facilitate sensitive, specific detection of the four novel groups of SRB in livestock waste storage systems.     

Successional development of sulfate-reducing bacterial populations and their activities in an activated sludge immobilized agar gel film

A combination of fluorescence in situ hybridization (FISH), microprofiles, and denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rDNA fragments followed by hybridization analysis with specific probes was applied to investigate successional development of sulfate-reducing bacteria (SRB) community structure and in situ sulfide production activity within an activated sludge immobilized agar gel film. In this model biofilm system, since biases arising from biofilm heterogeneity can be ignored, the population dynamics of SRB in the agar gel is directly related to physiological capability and in situ activity of SRB. Microelectrode measurements showed that an anoxic zone was already developed at the beginning (0 day), a first sulfide production of 0.054 mumol H2S m(-2) x s(-1) was detected during the first week, and the rate increased gradually to 0.221 mumol H2S m(-2) x s(-1) in the fifth week. The most active sulfide production zone moved upward to the chemocline and intensified with time to form a narrow zone with high volumetric sulfide production rates. This result coincided with the shift of the spatial distributions of SRB populations determined by FISH. In situ hybridization with probe SRB385 for mainly general SRB of the delta Proteobacteria plus some gram-positive bacteria and probe 660 for Desulfobulbus indicated that the most abundant populations of SRB were primarily restricted to near the oxic/anoxic interface (chemocline). A close observation of the development of the vertical distributions of SRB populations revealed that the cell numbers of Desulfobulbus tripled (from 0.5 x 10(8) to 1.5 x 10(8) cells cm(-3)) near the oxic/anoxic interface. Similar growth (from 1.0 x10(8) to 4.5 x 10(8) cells cm(-3)) of Desulfovibrio-like SRB that hybridized with probe SRB385 was observed. PCR-DGGE followed by hybridization analysis revealed that one Desulfobulbus strain was detected from the beginning, and another strain appeared after 1 week, coinciding with the first detected sulfide production. In addition, three strains hybridizing with probe 687 (possibly Desulfovibrio) were also dominant SRB in the agar gel.     

Nitrite reductase activity of sulphate-reducing bacteria prevents their inhibition by nitrate-reducing,sulphide-oxidizing bacteria

Sulphate-reducing bacteria (SRB) can be inhibited by nitrate-reducing, sulphide-oxidizing bacteria (NR-SOB), despite the fact that these two groups are interdependent in many anaerobic environments. Practical applications of this inhibition include the reduction of sulphide concentrations in oil fields by nitrate injection. The NR-SOB Thiomicrospira sp. strain CVO was found to oxidize up to 15 mM sulphide, considerably more than three other NR-SOB strains that were tested. Sulphide oxidation increased the environmental redox potential (Eh) from -400 to +100 mV and gave 0.6 nitrite per nitrate reduced. Within the genus Desulfovibrio, strains Lac3 and Lac6 were inhibited by strain CVO and nitrate for the duration of the experiment, whereas inhibition of strains Lac15 and D. vulgaris Hildenborough was transient. The latter had very high nitrite reductase (Nrf) activity. Southern blotting with D. vulgaris nrf genes as a probe indicated the absence of homologous nrf genes from strains Lac3 and Lac6 and their presence in strain Lac15. With respect to SRB from other genera, inhibition of the known nitrite reducer Desulfobulbus propionicus by strain CVO and nitrate was transient, whereas inhibition of Desulfobacterium autotrophicum and Desulfobacter postgatei was long-lasting. The results indicate that inhibition of SRB by NR-SOB is caused by nitrite production. Nrf-containing SRB can overcome this inhibition by further reducing nitrite to ammonia, preventing a stalling of the favourable metabolic interactions between these two bacterial groups. Nrf, which is widely distributed in SRB, can thus be regarded as a resistance factor that prevents the inhibition of dissimilatory sulphate reduction by nitrite.     

3‐photon fluorescence imaging of sulforhodamine B‐labeled elastic fibers in the mouse skin in vivo

Elastic fibers are key constituents of the skin. The commonly adopted optical technique for visualizing elastic fibers in the animal skin in vivo is 2‐photon microscopy (2 PM) of autofluorescence, which typically suffers from low signal level. Here we demonstrate a new optical methodology to image elastic fibers in animal models in vivo: 3‐photon microscopy (3 PM) excited at the 1700‐nm window combining with preferential labeling of elastic fibers using sulforhodamine B (SRB). First, we demonstrate that intravenous injection of SRB can circumvent the skin barrier (encountered in topical application) and preferentially label elastic fibers, as verified by simultaneous 2 PM of both autofluorescence and SRB fluorescence from skin structures. Then through 3‐photon excitation property characterization, we show that 3‐photon fluorescence can be excited from SRB at the 1700‐nm window, and 1600‐nm excitation is most efficient according to our 3‐photon action cross section measurement. Based on these results and using our developed 1600‐nm femtosecond laser source, we finally demonstrate 3 PM of SRB‐labeled elastic fibers through the whole dermis in the mouse skin in vivo, with only 3.7‐mW optical power deposited on the skin surface. We expect our methodology will provide novel optical solution to elastic fiber research.     

Direct immobilisation of antibodies on a bioinspired architecture as a sensing platform

A sensitive and selective immunosensor for the nonlabeled detection of sulfate-reducing bacteria (SRB) is constructed using a self-polymerised polydopamine film as the immobilisation platform. Self-polymerisation of dopamine is used as a powerful approach for applying multifunctional coatings onto the surface of a gold electrode. The polydopamine film is used not only as the immobilisation platform, but also as a cross-linker reagent for the immobilisation of the anti-SRB antibody. The polydopamine film is loaded with a high density of anti-SRB antibodies linked to the substrate to obtain high response signals. The formation and fabrication of the biosensor and the quantification of antibody anchoring are monitored, and SRB detection is performed by either quartz crystal microbalance (QCM) or electrochemical impedance spectroscopy (EIS). After modeling the impedance Nyquist plots of the SRB/anti-SRB/polydopamine/gold electrode for increasing concentrations of SRB, the electron transfer resistance (R(ct)) is used as a measure of immunocomplex binding. The R(ct) is correlated with the concentration of bacterial cells in the range of 1.8×10(2) to 1.8×10(6) CFU mL(-1); the detection limit is 50 CFU mL(-1). This work demonstrates a new immobilisation platform for the development of a sensitive and label-less impedimetric and piezoelectric immunosensor. This immunosensor may be broadly applied in clinical diagnoses and the monitoring of water environmental pollution. The method proposed is distinct in its ease of application, use of a simple protocol, and mild reaction conditions. These allow it to be applied to a wide variety of materials.     

一株高耐镉硫酸盐还原菌的分离及脱硫性能研究

本研究从镉污染稻田水稻根际土壤中分离、纯化出一株硫酸盐还原菌SRB1-1,并对该菌株的生理生态特征、镉和盐耐受性、16S rDNA、脱硫性能及影响因子进行了系列分析。结果表明,该菌为革兰氏阴性菌,菌体弧状,对镉离子的耐受浓度可达200 mg/L,在2%的氯化钠浓度下仍可生长。对其16S rDNA的序列分析表明该菌株属于脱硫弧菌属(Desulfovibrio)。单因子实验考察温度、pH及SO_4~(2-)浓度对该菌脱硫效率的影响,正交实验确定了该菌最佳脱硫工艺条件及影响因子顺序。结果表明最佳脱硫工艺条件为pH 7.5、温度40℃、SO_4~(2-)浓度为1 000 mg/L、培养时间56 h。