结合微生物生长繁殖所必需的水、营养物、温度及酸碱度等条件,对飞机燃油在生产、运输、储存及飞机日常使用维护过程中可能出现微生物污染原因进行分析；结合燃油系统中微生物生长繁殖特性,总结了微生物对燃油性能、油箱结构、油泵/油滤以及非金属材料的危害作用。此外,对比分析了现有飞机燃油系统微生物检测方法及其标准,并对国外飞机燃油系统微生物预防措施及流程进行分析。本综述将为我国今后飞机燃油系统微生物污染检测及预防等工作提供理论基础及研究方向,并在工程应用方面起到指导性作用。

Microbial contamination poses a great threat to aviation system security through mechanisms such as microbiologically influenced corrosion (MIC), fuel filter clogging, and fuel deterioration. In this study, a survey of microbial contamination in aviation fuel obtained from aircraft fuel tanks was performed to test the relationship between microbial contamination and aircraft service life. The contaminating microorganisms were counted, isolated, identified, and subjected to preliminary characterization. A low risk of microbial contamination in the selected samples was confirmed, and there was no significant difference in the counts between culturable bacteria and fungi (p > 0.05). Phylogenetic analysis tree indicated that the diversity of culturable microorganisms was rather low, with 17 bacterial isolates belonging to 13 genera and 12 fungal isolates belonging to 5 genera. No yeast was isolated. The growth characteristics of these isolates indicated that the aircraft fuel tanks harbored various microorganisms that were able to utilize the aviation fuel as a source of carbon and energy. Meanwhile, some isolates caused emulsification and produced acid. The conclusions of this study were that various hazardous microorganisms can root in aircraft aviation fuel tanks. There was no relationship between microbial contamination and aircraft service life (p > 0.05), and continuous good maintenance suppressed microbial proliferation.

为探究温度对原油储罐罐底微生物腐蚀 (均匀腐蚀和局部腐蚀) 的影响规律与机理,采用16S rRNA基因测序分析微生物种群的特征,利用扫描电镜、激光共聚焦显微镜观察微生物膜的形态和点蚀坑特征。结果表明,罐底水微生物含有嗜温和嗜热的硫酸盐还原菌 (SRB) 和腐生菌 (TGB),均匀腐蚀速率在65 ℃达到峰值,整体属于轻微腐蚀；点蚀速率在35 ℃达到峰值,达到0.8 mm/a,温度低于25 ℃及超过85 ℃后点蚀速率明显降低。温度对罐底板钢微生物腐蚀的影响与微生物种类耐温性有关,30~70 ℃间是点蚀敏感温度区间,点蚀坑与菌落的团簇生长有关,微生物首先在金属表面形成团簇状的菌落,然后代谢过程中菌落下的金属发生了快速腐蚀。

利用失重法、电化学极化法、电化学阻抗谱及腐蚀形貌观察和腐蚀产物物相分析，研究了油水分层介质中X65管线钢在油水两相界面处的腐蚀行为及不同缓蚀剂在油水界面处的作用效果。结果表明，在CO₂分压为0.9 MPa，温度为60 ℃，静止状态下的油水分层介质中，X65钢在油相区几乎不发生腐蚀，在油水两相界面处发生局部腐蚀，在水相区发生严重腐蚀。添加水溶性缓蚀剂十七烯基胺乙基咪唑啉季铵盐使得X65钢在该工况下的腐蚀速率降低，添加油溶性缓蚀剂癸硫醇反而使得X65钢在油水两相界面处的局部腐蚀加重，甚至出现了腐蚀沟槽。

结合近年来杀菌剂的研究和应用情况，针对不同类型微生物腐蚀现象，综述了油气田中用于防控细菌腐蚀的季铵盐类、胍类、杂环类和复配型杀菌剂的研究进展。对于目前研究较少的真菌和藻类所造成的微生物腐蚀，本文介绍了真菌和藻类诱导的金属腐蚀行为以及目前针对真菌和藻类杀菌剂的研究进展和应用情况。在此基础上总结了杀菌剂应用所面临的问题和未来发展趋势，为微生物腐蚀防护和杀菌剂的研究及合理使用提供参考。

结合杂环化合物和季铵盐表面活性剂用作缓蚀剂和杀菌剂的结构特点，合成了含噻二唑杂环的季铵盐表面活性剂 (MTOTB)，并采用¹HNMR、ESI-MS和FT-IR对其结构进行表征。采用表面张力法研究其表面活性，采用电化学测试和表面分析的方法研究其在含硫酸盐还原菌 (SRB) 的模拟海水中对碳钢的缓蚀性能。结果表明，MTOTB在模拟海水中的临界胶束浓度为0.11 mmol/L。MTOTB浓度为0.2 mmol/L时，对在含SRB菌的模拟海水中浸泡21 d的碳钢的缓蚀率可达95.81%。SEM/EDS与XPS结果表明，MTOTB可以有效地吸附在碳钢表面，抑制碳钢的微生物腐蚀。

Silver nanoparticles have already been successfully applied in various biomedical and antimicrobial technologies and products used in everyday life. Although bacterial resistance to antibiotics has been extensively discussed in the literature, the possible development of resistance to silver nanoparticles has not been fully explored. We report that the Gram-negative bacteria Escherichia coli 013, Pseudomonas aeruginosa CCM 3955 and E. coli CCM 3954 can develop resistance to silver nanoparticles after repeated exposure. The resistance stems from the production of the adhesive flagellum protein flagellin, which triggers the aggregation of the nanoparticles. This resistance evolves without any genetic changes; only phenotypic change is needed to reduce the nanoparticles' colloidal stability and thus eliminate their antibacterial activity. The resistance mechanism cannot be overcome by additional stabilization of silver nanoparticles using surfactants or polymers. It is, however, strongly suppressed by inhibiting flagellin production with pomegranate rind extract.

Despite the current advancement in drug discovery and pharmaceutical biotechnology, infection diseases induced by bacteria continue to be one of the greatest health problems worldwide, afflicting millions of people annually. Almost all microorganisms have, in fact, an intrinsic outstanding ability to flout many therapeutic interventions, thanks to their fast and easy-to-occur evolutionary genetic mechanisms. At the same time, big pharmaceutical companies are losing interest in new antibiotics development, shifting their capital investments in much more profitable research and development fields. New smart solutions are, thus, required to overcome such concerns, and should combine the feasibility of industrial production processes with cheapness and effectiveness. In this framework, nanotechnology-based solutions, and in particular silver nanoparticles (AgNPs), have recently emerged as promising candidates in the market as new antibacterial agents. AgNPs display, in fact, enhanced broad-range antibacterial/antiviral properties, and their synthesis procedures are quite cost effective. However, despite their increasing impact on the market, many relevant issues are still open. These include the molecular mechanisms governing the AgNPs-bacteria interactions, the physico-chemical parameters underlying their toxicity to prokaryotes, the lack of standardized methods and materials, and the uncertainty in the definition of general strategies to develop smart antibacterial drugs and devices based on nanosilver. In this review, we analyze the experimental data on the bactericidal effects of AgNPs, discussing the complex scenario and presenting the potential drawbacks and limitations in the techniques and methods employed. Moreover, after analyzing in depth the main mechanisms involved, we provide some general strategies/procedures to perform antibacterial tests of AgNPs, and propose some general guidelines for the design of antibacterial nanosystems and devices based on silver/nanosilver.

Titanium embedded with silver nanoparticles (Ag NPs) using a single step silver plasma immersion ion implantation (Ag-PIII) demonstrate micro-galvanic effects that give rise to both controlled antibacterial activity and excellent compatibility with osteoblasts. Scanning electron microscopy (SEM) shows that nanoparticles with average sizes of about 5 nm and 8 nm are formed homogeneously on the titanium surface after undergoing Ag-PIII for 0.5 h and 1 h, respectively. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) indicate that those nanoparticles are metallic silver produced on and underneath the titanium surface via a local nucleation process from the solid solution of α-Ti(Ag). The Ag-PIII samples inhibit the growth of both Staphylococcus aureus and Escherichia coli while enhancing proliferation of the osteoblast-like cell line MG63. Electrochemical polarization and Zeta potential measurements demonstrate that the low surface toxicity and good cytocompatibility are related to the micro-galvanic effect between the Ag NPs and titanium matrix. Our results show that the physico-chemical properties of the Ag NPs are important in the control of the cytotoxicity and this study opens a new window for the design of nanostructured surfaces on which the biological actions of the Ag NPs can be accurately tailored.Copyright © 2010 Elsevier Ltd. All rights reserved.

结合近年来铝合金霉菌腐蚀机制与防护领域研究成果，介绍了代表性霉菌的种类及影响霉菌活性的主要因素，重点总结和讨论了铝合金霉菌腐蚀机制，主要包括酸蚀机制、浓差电池机制、以及其他可能存在直接电子传递机制和霉菌铝合金直接界面作用机制。霉菌通过新陈代谢可以产生大量的有机酸，能够显著地降低介质和生物膜内的pH，从而导致酸蚀引发局部腐蚀。霉菌在铝合金表面形成的生物膜是诱发氧浓差电池产生的原因之一，铝合金霉菌腐蚀过程中潜在的直接电子传递及铝合金和霉菌的直接界面作用也是导致铝合金局部腐蚀的重要原因之一。最后介绍了目前常用的铝合金霉菌腐蚀控制方法，展望了未来铝合金霉菌腐蚀的研究重点，为铝合金霉菌腐蚀研究提供参考。

Reactive oxygen species (ROS) can attack a diverse range of targets to exert antimicrobial activity, which accounts for their versatility in mediating host defense against a broad range of pathogens. Most ROS are formed by the partial reduction in molecular oxygen. Four major ROS are recognized comprising superoxide (O2•-), hydrogen peroxide (H2O2), hydroxyl radical (•OH), and singlet oxygen ((1)O2), but they display very different kinetics and levels of activity. The effects of O2•- and H2O2 are less acute than those of •OH and (1)O2, because the former are much less reactive and can be detoxified by endogenous antioxidants (both enzymatic and nonenzymatic) that are induced by oxidative stress. In contrast, no enzyme can detoxify •OH or (1)O2, making them extremely toxic and acutely lethal. The present review will highlight the various methods of ROS formation and their mechanism of action. Antioxidant defenses against ROS in microbial cells and the use of ROS by antimicrobial host defense systems are covered. Antimicrobial approaches primarily utilizing ROS comprise both bactericidal antibiotics and nonpharmacological methods such as photodynamic therapy, titanium dioxide photocatalysis, cold plasma, and medicinal honey. A brief final section covers reactive nitrogen species and related therapeutics, such as acidified nitrite and nitric oxide-releasing nanoparticles.© 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Centralized water treatment has dominated in developed urban areas over the past century, although increasing challenges with this model demand a shift to a more decentralized approach wherein advanced oxidation processes (AOPs) can be appealing treatment options. Efforts to overcome the fundamental obstacles that have thus far limited the practical use of traditional AOPs, such as reducing their chemical and energy input demands, target the utilization of heterogeneous catalysts. Specifically, recent advances in nanotechnology have stimulated extensive research investigating engineered nanomaterial (ENM) applications to AOPs. In this Perspective, we critically evaluate previously studied ENM catalysts and the next-generation treatment technologies they seek to enable. Opportunities for improvement exist at the intersection of materials science and treatment process engineering, as future research should aim to enhance catalyst properties while considering the unique roadblocks to practical ENM implementation in water treatment.

This perspective article reviews recent advances in the study of important catalytic reactions on gold electrodes. The paper discusses both oxidation and reduction reactions: the oxidation of carbon monoxide and alcohols as well as the oxygen reduction reaction on gold electrodes and also a brief discussion of other interesting reactions on gold electrodes such as the amine borane oxidation and the CO2 reduction. A common theme in electrocatalysis on gold is the sensitive dependence of various reaction rates on pH and gold surface structure. The electrocatalysis of redox reactions on gold is highly pH dependent, often preferring alkaline media, due to the prominent role of negatively charged reaction intermediates related to the fact that gold does not bind the neutral intermediates strongly enough. Gold also tends to be a selective catalyst, again due to its weak adsorption properties, as on gold the reaction often stops when a difficult bond breaking or making event will be the necessary next step.

Future generations require more efficient and localized processes for energy conversion and chemical synthesis. The continuous on-site production of hydrogen peroxide would provide an attractive alternative to the present state-of-the-art, which is based on the complex anthraquinone process. The electrochemical reduction of oxygen to hydrogen peroxide is a particularly promising means of achieving this aim. However, it would require active, selective and stable materials to catalyse the reaction. Although progress has been made in this respect, further improvements through the development of new electrocatalysts are needed. Using density functional theory calculations, we identify Pt-Hg as a promising candidate. Electrochemical measurements on Pt-Hg nanoparticles show more than an order of magnitude improvement in mass activity, that is, A g(-1) precious metal, for H2O2 production, over the best performing catalysts in the literature.

Although it has long been known that microbes can generate energy using diverse strategies, only recently has it become clear that a growing number involve electron transfer to or from extracellular substrates. The best-known example of what we will term 'extracellular respiration' is electron transfer between microbes and minerals, such as iron and manganese (hydr)oxides. This makes sense, given that these minerals are sparingly soluble. What is perhaps surprising, however, is that a number of substrates that might typically be classified as 'soluble' are also respired at the cell surface. There are several reasons why this might be the case: the substrate, in its ecological context, might be associated with a solid surface and thus effectively insoluble; the substrate, while soluble, might simply be too large to transport inside the cell; or the substrate, while benign in one redox state, might become toxic after it is metabolized. In this review, we discuss various examples of extracellular respiration, paying particular attention to what is known about the molecular mechanisms underlying these processes. As will become clear, much remains to be learned about the biochemistry, cell biology and regulation of extracellular respiration, making it a rich field of study for molecular microbiologists.

\n An extension of the respiratory chain to the cell surface is necessary to reduce extracellular electron acceptors like ferric iron or manganese oxides. In the past few years, more and more compounds were revealed to be reduced at the surface of the outer membrane of Gram-negative bacteria, and the list does not seem to have an end so far.\n Shewanella\n as well as\n Geobacter\n strains are model organisms to discover the biochemistry that enables the dissimilatory reduction of extracellular electron acceptors. In both cases,\n c\n -type cytochromes are essential electron-transferring proteins. They make the journey of respiratory electrons from the cytoplasmic membrane through periplasm and over the outer membrane possible. Outer membrane cytochromes have the ability to catalyze the last step of the respiratory chains. Still, recent discoveries provided evidence that they are accompanied by further factors that allow or at least facilitate extracellular reduction. This review gives a condensed overview of our current knowledge of extracellular respiration, highlights recent discoveries, and discusses critically the influence of different strategies for terminal electron transfer reactions.\n

Redox cycling of extracellular electron shuttles can enable the metabolic activity of subpopulations within multicellular bacterial biofilms that lack direct access to electron acceptors or donors. How these shuttles catalyze extracellular electron transfer (EET) within biofilms without being lost to the environment has been a long-standing question. Here, we show that phenazines mediate efficient EET through interactions with extracellular DNA (eDNA) in Pseudomonas aeruginosa biofilms. Retention of pyocyanin (PYO) and phenazine carboxamide in the biofilm matrix is facilitated by eDNA binding. In vitro, different phenazines can exchange electrons in the presence or absence of DNA and can participate directly in redox reactions through DNA. In vivo, biofilm eDNA can also support rapid electron transfer between redox active intercalators. Together, these results establish that PYO:eDNA interactions support an efficient redox cycle with rapid EET that is faster than the rate of PYO loss from the biofilm.Copyright © 2020 Elsevier Inc. All rights reserved.

The process of microbial extracellular electron transfer (EET) is widespread in nature and has broad application prospects in energy utilization and environmental remediation. However, inefficient electron transfer has always been a key bottleneck in practical applications. Nanomaterials have unique properties such as surface effect, volume effect, quantum size, and macro-quantum tunneling effect. The combination of nanomaterials and electroactive microorganisms can achieve complementary advantages, which can shorten the charge transfer path and increase the rate of EET. This review introduces the pathways of EET, as well as the factors affecting the interface EET such as the electron transfer ability, redox potential, surface structure and biocompatibility of nanomaterials, with a focus on various strategies for constructing the interface between nanomaterials and electroactive microorganisms, and the applicability and limitations of these strategies are summarized. Finally, the future research direction of nanomaterials to enhance electroactive microorganism EET is prospected.

微生物胞外电子传递（EET）过程在自然界中普遍存在，并且在能源利用和环境修复等方面具有广阔的应用前景，但是低效的电子传递一直是其在实际应用中的关键瓶颈。纳米材料具有独特的表面效应、体积效应、量子尺寸及宏观量子隧道效应等性质，引入纳米材料与电活性微生物相结合实现优势互补，可以缩短电荷转移路径，从而提高EET效率。本文综述了EET方式，以及纳米材料的电子转移能力、氧化还原电势、表面结构与性质、生物相容性及纳米材料-微生物的界面构筑对EET过程的影响，重点阐述了纳米材料与电活性微生物界面构筑的各种策略，并讨论了这些策略的适用性和局限性，最后展望了纳米材料强化电活性微生物EET的未来研究方向。

Electrical interactions between bacteria and the environment are delicate and essential. In this study, an external electrical current is applied to capacitive titania nanotubes doped with carbon (TNT-C) to evaluate the effects on bacteria killing and the underlying mechanism is investigated. When TNT-C is charged, post-charging antibacterial effects proportional to the capacitance are observed. This capacitance-based antibacterial system works well with both direct and alternating current (DC, AC) and the higher discharging capacity in the positive DC (DC+) group leads to better antibacterial performance. Extracellular electron transfer observed during early contact contributes to the surface-dependent post-charging antibacterial process. Physiologically, the electrical interaction deforms the bacteria morphology and elevates the intracellular reactive oxygen species level without impairing the growth of osteoblasts. Our finding spurs the design of light-independent antibacterial materials and provides insights into the use of electricity to modify biomaterials to complement other bacteria killing measures such as light irradiation.

Clinically, it is difficult to endow implants with excellent osteogenic ability and antibacterial activity simultaneously. Herein, the self-activating implants modified with hydroxyapatite (HA)/MoS coating are designed to prevent Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) infections and accelerate bone regeneration simultaneously. The electron transfer between bacteria and HA/MoS is triggered when bacteria contacted with the material. RNA sequencing data reveals that the expression level of anaerobic respiration-related genes is up-regulated and the expression level of aerobic respiration-related genes is down-regulated when bacteria adhere to the implants. HA/MoS presents a highly effective antibacterial efficacy against both S. aureus and E. coli because of bacterial respiration-activated metabolic pathway changes. Meanwhile, this coating promotes the osteoblastic differentiation of mesenchymal stem cells by altering the potentials of cell membrane and mitochondrial membrane. The proposed strategy exhibits great potential to endow implants with self-activating anti-infection performance and osteogenic ability simultaneously.© 2021. The Author(s).