Nanomechanics of Drug-target Interactions and Antibacterial Resistance Detection

The cantilever sensor, which acts as a transducer of reactions between model bacterial cell wall matrix immobilized on its surface and antibiotic drugs in solution, has shown considerable potential in biochemical sensing applications with unprecedented sensitivity and specificity^1-5. The drug-target interactions generate surface stress, causing the cantilever to bend, and the signal can be analyzed optically when it is illuminated by a laser. The change in surface stress measured with nano-scale precision allows disruptions of the biomechanics of model bacterial cell wall targets to be tracked in real time. Despite offering considerable advantages, multiple cantilever sensor arrays have never been applied in quantifying drug-target binding interactions.Here, we report on the use of silicon multiple cantilever arrays coated with alkanethiol self-assembled monolayers mimicking bacterial cell wall matrix to quantitatively study antibiotic binding interactions. To understand the impact of vancomycin on the mechanics of bacterial cell wall structures^1,6,7. We developed a new model¹ which proposes that cantilever bending can be described by two independent factors; i) namely a chemical factor, which is given by a classical Langmuir adsorption isotherm, from which we calculate the thermodynamic equilibrium dissociation constant (K_d) and ii) a geometrical factor, essentially a measure of how bacterial peptide receptors are distributed on the cantilever surface. The surface distribution of peptide receptors (p) is used to investigate the dependence of geometry and ligand loading. It is shown that a threshold value of p ~10% is critical to sensing applications. Below which there is no detectable bending signal while above this value, the bending signal increases almost linearly, revealing that stress is a product of a local chemical binding factor and a geometrical factor combined by the mechanical connectivity of reacted regions and provides a new paradigm for design of powerful agents to combat superbug infections.     

棕榈的综合利用和开发

棕榈[Trachycarpus fortunei(Hook.)H.Wendl.]是中国最普遍、应用最广的棕榈科植物之一,也是能够广泛地生长在亚热带和温带最耐寒的棕榈科植物.在中国棕榈是重要的经济植物,棕榈的每一部分都能利用,新鲜花可以吃,种子用作饲料,树干能建房.近来研究表明,棕榈的种子、叶、茎、根、花中含多种化学成分,作者及合作者已经开发出止血药"血安"和植物蜡.棕榈仍然具有很大潜力,棕榈种子和叶中含有多酚、黄酮、甾体皂苷等生物活性成分,有可能开发出治疗心血管病和肿瘤的药物.     

Application of an In vitro DNA Protection Assay to Visualize Stress Mediation Properties of the Dps Protein

Oxidative stress is an unavoidable byproduct of aerobic life. Molecular oxygen is essential for terrestrial metabolism, but it also takes part in many damaging reactions within living organisms. The combination of aerobic metabolism and iron, which is another vital compound for life, is enough to produce radicals through Fenton chemistry and degrade cellular components. DNA degradation is arguably the most damaging process involving intracellular radicals, as DNA repair is far from trivial. The assay presented in this article offers a quantitative technique to measure and visualize the effect of molecules and enzymes on radical-mediated DNA damage.The DNA protection assay is a simple, quick, and robust tool for the in vitro characterization of the protective properties of proteins or chemicals. It involves exposing DNA to a damaging oxidative reaction and adding varying concentrations of the compound of interest. The reduction or increase of DNA damage as a function of compound concentration is then visualized using gel electrophoresis. In this article we demonstrate the technique of the DNA protection assay by measuring the protective properties of the DNA-binding protein from starved cells (Dps). Dps is a mini-ferritin that is utilized by more than 300 bacterial species to powerfully combat environmental stressors. Here we present the Dps purification protocol and the optimized assay conditions for evaluating DNA protection by Dps.     

高压氧的应用进展

高压氧逐渐被广泛的应用于多个医疗实践领域。作为一种特殊的治疗手段,临床医生会为他们的病人提供这种治疗选择,但对其机制却不十分了解。通过对高压氧作用机制详细阐述,为临床医生在医疗实践中提供科学依据。通过全面阐述高压氧的临床应用、并发症及禁忌症,更全面、系统的了解高压氧这种治疗手段,全面评估高压氧的治疗安全性。因高压氧具有增加氧输送、免疫功能和改变血液流变学的复合效应,而且安全性较高,用于治疗创伤、栓塞、感染等多种疾病。突发性耳聋是耳鼻咽喉科常见的急症,患者主要表现为突然发生的不同程度的感音神经聋,影响患者的生活。因目前突发性耳聋的病因尚不明确,治疗方案多种多样,如激素、抗凝药物、抗病毒药物等,但疗效均为得到肯定,无有效的统一治疗方案。通过分析评价多个随机对照试验,发现高压氧治疗可明显改善突发性耳聋（Sudden hearing loss,SHL）的听力下降,希望能为临床医生的治疗提供科学依据。可能存在其他的尚未发掘的治疗领域,期待临床上有更多的相关研究。     

高压氧的应用进展

高压氧逐渐被广泛的应用于多个医疗实践领域。作为一种特殊的治疗手段,临床医生会为他们的病人提供这种治疗选择,但对其机制却不十分了解。通过对高压氧作用机制详细阐述,为临床医生在医疗实践中提供科学依据。通过全面阐述高压氧的临床应用、并发症及禁忌症,更全面、系统的了解高压氧这种治疗手段,全面评估高压氧的治疗安全性。因高压氧具有增加氧输送、免疫功能和改变血液流变学的复合效应,而且安全性较高,用于治疗创伤、栓塞、感染等多种疾病。突发性耳聋是耳鼻咽喉科常见的急症,患者主要表现为突然发生的不同程度的感音神经聋,影响患者的生活。因目前突发性耳聋的病因尚不明确,治疗方案多种多样,如激素、抗凝药物、抗病毒药物等,但疗效均为得到肯定,无有效的统一治疗方案。通过分析评价多个随机对照试验,发现高压氧治疗可明显改善突发性耳聋(Sudden hearing loss,SHL)的听力下降,希望能为临床医生的治疗提供科学依据。可能存在其他的尚未发掘的治疗领域,期待临床上有更多的相关研究。     

Vertical T-maze Choice Assay for Arthropod Response to Odorants

Given the economic importance of insects and arachnids as pests of agricultural crops, urban environments or as vectors of plant and human diseases, various technologies are being developed as control tools. A subset of these tools focuses on modifying the behavior of arthropods by attraction or repulsion. Therefore, arthropods are often the focus of behavioral investigations. Various tools have been developed to measure arthropod behavior, including wind tunnels, flight mills, servospheres, and various types of olfactometers. The purpose of these tools is to measure insect or arachnid response to visual or more often olfactory cues. The vertical T-maze oflactometer described here measures choices performed by insects in response to attractants or repellents. It is a high throughput assay device that takes advantage of the positive phototaxis (attraction to light) and negative geotaxis (tendency to walk or fly upward) exhibited by many arthropods. The olfactometer consists of a 30 cm glass tube that is divided in half with a Teflon strip forming a T-maze. Each half serves as an arm of the olfactometer enabling the test subjects to make a choice between two potential odor fields in assays involving attractants. In assays involving repellents, lack of normal response to known attractants can also be measured as a third variable.     

Documented Utility and Biocultural Value of <Emphasis Type="Italic">Aloe</Emphasis> L. (Asphodelaceae): A Review

Documented Utility and Biocultural Value of Aloe L. (Asphodelaceae): A Review. The genus Aloe L. (Asphodelaceae) comprises 548 accepted species, of which at least one-third are documented as having some utilitarian value. The group is of conservation concern due to habitat loss and being extensively collected from the wild for horticulture and natural products. Cultural value is increasingly important in the effective conservation of biodiversity. The present study evaluated the biocultural value of the known uses of Aloe, excluding the domesticated and commercially cultivated A. vera. Over 1,400 use records representing 173 species were collated from the literature and through personal observation; this paper presents a synopsis of uses in each of 11 use categories. Medicinal uses of Aloe were described by 74% of the use records, followed by social and environmental uses (both 5%). Species yielding natural products, notably A. ferox and A. perryi, were most frequently cited in the literature. Consensus ratios indicate that the most valued uses of Aloe are in medicine and pest control against arthropods and other invertebrates.     

Use of woody plants by locals in Mare aux Hippopotames Biosphere Reserve in western Burkina Faso

The central area of the Mare aux Hippopotames Biosphere Reserve is located in the western part of Burkina Faso. Local populations have a close relationship with the reserve, from which they get much of their needs in food products, medicine, energy, arts and crafts. The use of resources has consequences for the biodiversity, ecosystem and environment of the reserve. The discussions held during ethnobotanical inquiries have permitted us to establish the main uses of woody plants and to pick out the repercussions of this usage. From this it emerges that the reserve has an important floristic richness and a biodiversity unknown to both locals and authorities.