纳米材料修饰微生物燃料电池阳极的研究进展

阳极作为微生物燃料电池中的重要组成部分,其性能的高低显著影响着微生物燃料电池的产电性能。纳米材料具有导电性好、表面积大等优良特性。因此,纳米材料修饰阳极能够有效减小电极内阻、增大微生物的粘附量,从而显著提高微生物燃料电池的产电性能。本文首先简要介绍了微生物燃料电池中阳极修饰纳米材料的种类,然后重点归纳了不同纳米材料修饰阳极对微生物燃料电池产电性能的影响及其原因。最后对微生物燃料电池阳极修饰纳米材料和技术进行展望。     

Unraveling the resistance of microbial biofilms: has proteomics been helpful?

Biofilms are surface-attached, matrix-encased, structured microbial communities which display phenotypic features that are dramatically different from those of their free-floating, or planktonic, counterparts. Biofilms seem to be the preferred mode of growth of microorganisms in nature, and at least 65% of all human infections are associated with biofilms. The most notable and clinically relevant property of biofilms is their greater resistance to antimicrobials compared with their planktonic counterparts. Although both bacterial and fungal biofilms display this phenotypic feature, the exact mechanisms underlying their increased drug resistance are yet to be determined. Advances in proteomics techniques during the past decade have facilitated in-depth analysis of the possible mechanisms underpinning increased drug resistance in biofilms. These studies have demonstrated the ability of proteomics techniques to unravel new targets for combating microbial biofilms. In this review, we discuss the putative drug resistance mechanisms of microbial biofilms that have been uncovered by proteomics and critically evaluate the possible contribution of the new knowledge to future development in the field. We also summarize strategic uses of novel proteomics technologies in studies related to drug resistance mechanisms of microbial biofilms.     

Microbial considerations in genetically engineered mouse research

Microbial infections have long been of concern to scientists using laboratory rodents because of their potential to confound and invalidate research. With the explosion of genetically engineered mice (GEM), new concerns over the impact of microbial agents have emerged because these rodents in many cases are more susceptible to disease than their inbred or outbred counterparts. Moreover, interaction between microbe and host and the resulting manifestation of disease conceivably differ between GEM and their inbred and outbred counterparts. As a result, infections may alter the GEM phenotype and confound interpretation of results and conclusions about mutated gene function. In addition, because GEM are expensive to produce and maintain, contamination by pathogens or opportunists has severe economic consequences. This review addresses how microbial infections may influence phenotype, how immunomodulation of the host as the result of induced mutations may modify host susceptibility to microbial infections, how novel host:microbe interactions have led to the development of new animal models for disease, how phenotype changes have led to the discovery of new pathogens, and new challenges associated with prevention and control of microbial infections in GEM. Although the focus is on naturally occurring infections, extensive literature on the use of GEM in studies of microbial pathogenesis also exists, and the reader is referred to this literature if microbial infection is a suspected culprit in phenotype alteration.     

Bactericidal,quorum quenching and anti-biofilm nanofactories: a new niche for nanotechnologists

Despite several conventional potent antibacterial therapies, bacterial infections pose a significant threat to human health because they are emerging as the leading cause of death worldwide. Due to the development of antibiotic resistance in bacteria, there is a pressing demand to discover novel approaches for developing more effective therapies to treat multidrug-resistant bacterial strains and biofilm-associated infections. Therefore, attention has been especially devoted to a new and emerging branch of science “nanotechnology” to design non-conventional antimicrobial chemotherapies. A range of nanomaterials and nano-sized carriers for conventional antimicrobial agents have fully justified their potential to combat bacterial diseases by reducing cell viability, by attenuating quorum sensing, and by inhibiting/or eradicating biofilms. This communication summarizes emerging nano-antimicrobial therapies in treating bacterial infections, particularly using antibacterial, quorum quenching, and anti-biofilm nanomaterials as new approaches to tackle the current challenges in combating infectious diseases.     

群体感应与微生物耐药性

微生物耐药性已成为全球关注的严重问题,其演化机制和调控机理也已成为研究热点。近年来的研究发现,一些微生物耐药性机制受到群体感应系统的调控。群体感应是一种在微生物界广泛存在并与菌体密度关联的细胞-细胞间的通讯系统。高密度的菌落群体能够产生足够数量的小分子信号,激活下游包括致病毒力和耐药性机制在内的多种细胞进程,耐受抗生素并且危害寄主。本文结合国内外最新的研究进展,对微生物群体感应系统的研究现状进行了概括性介绍,重点阐述了群体感应系统对微生物耐药性机制的调控作用,如微生物生物被膜形成和药物外排泵调控等方面的作用,并探讨了利用群体淬灭控制微生物耐药性的新策略。     

Genetic control of Candida albicans biofilm development

Candida species cause frequent infections owing to their ability to form biofilms - surface-associated microbial communities - primarily on implanted medical devices. Increasingly, mechanistic studies have identified the gene products that participate directly in the development of Candida albicans biofilms, as well as the regulatory circuitry and networks that control their expression and activity. These studies have uncovered new mechanisms and signals that govern C. albicans biofilm development and associated drug resistance, thus providing biological insight and therapeutic foresight.     

Nanomaterials‐based biosensors for detection of microorganisms and microbial toxins

Detection of microorganisms and microbial toxins is important for health and safety. Due to their unique physical and chemical properties, nanomaterials have been extensively used to develop biosensors for rapid detection of microorganisms with microbial cells and toxins as target analytes. In this paper, the design principles of nanomaterials‐based biosensors for four selected analyte categories (bacteria cells, toxins, mycotoxins, and protozoa cells), closely associated with the target analytes' properties is reviewed. Five signal transducing methods that are less equipment intensive (colorimetric, fluorimetric, surface enhanced Raman scattering, electrochemical, and magnetic relaxometry methods) is described and compared for their sensory performance (in term oflimit of detection, dynamic range, and response time) for all analyte categories. In the end, the suitability of these five sensing principles for on‐site or field applications is discussed. With a comprehensive coverage of nanomaterials, design principles, sensing principles, and assessment on the sensory performance and suitability for on‐site application, this review offers valuable insight and perspective for designing suitable nanomaterials‐based microorganism biosensors for a given application.     

纳米酶的抗菌作用及其机制研究进展

抗生素类药物的发现和使用给人类提供了抗击细菌感染的强大武器。但是,抗生素长期使用导致的细菌耐药问题限制了其在临床上的应用。开发新型的基于纳米酶(Nano-Enzyme)的新型抗菌剂为解决上述问题提供了新思路。将纳米酶可以归为两大类:一类是酶和纳米材料的复合材料;另一类是纳米材料本身具有类酶活性。因为银(Ag)纳米粒子是历史最悠久且研究最广泛的纳米抗菌剂,而且其抗菌机制多样化,因此将Ag纳米粒子的抗菌机制和最新进展单独论述。纳米抗菌剂可以组合多种抗菌机制协同抗菌,从而提高其抗菌性能。因此,在这篇综述中系统介绍了Ag纳米粒子和上述2种类型纳米抗菌剂的最新研究进展和抗菌机制,重点介绍了纳米材料的物理性质对抗菌活性和生物安全性的影响。最后,该综述还强调了该领域目前面临的问题和挑战,并对该领域的发展前景进行了展望。     

人工纳米材料与生物膜相互作用机制及影响因素研究进展

人工纳米材料在水体中的环境行为与生物环境安全问题成为环境科学领域研究的热点,人工纳米材料与生物膜相互作用机制和影响因素是其中迫切需要研究解决的关键科学问题。本文主要探讨了人工纳米材料释放进入到水体中后对生物膜细菌活性、微生物群落结构、净污活性等的毒性效应,分析了人工纳米材料对生物膜的毒性作用机制及其影响因素,同时探讨了生物膜对人工纳米材料的吸附作用及机理,为深入研究人工纳米材料与生物膜的相互作用机制提供了重要的理论基础。     

Production of bioelectricity,bio-hydrogen,high value chemicals and bioinspired nanomaterials by electrochemically active biofilms

Microorganisms naturally form biofilms on solid surfaces for their mutual benefits including protection from environmental stresses caused by contaminants, nutritional depletion or imbalances. The biofilms are normally dangerous to human health due to their inherited robustness. On the other hand, a recent study suggested that electrochemically active biofilms (EABs) generated by electrically active microorganisms have properties that can be used to catalyze or control the electrochemical reactions in a range of fields, such as bioenergy production, bioremediation, chemical/biological synthesis, bio-corrosion mitigation and biosensor development. EABs have attracted considerable attraction in bioelectrochemical systems (BESs), such as microbial fuel cells and microbial electrolysis cells, where they act as living bioanode or biocathode catalysts. Recently, it was reported that EABs can be used to synthesize metal nanoparticles and metal nanocomposites. The EAB-mediated synthesis of metal and metal–semiconductor nanocomposites is expected to provide a new avenue for the greener synthesis of nanomaterials with high efficiency and speed than other synthetic methods. This review covers the general introduction of EABs, as well as the applications of EABs in BESs, and the production of bio-hydrogen, high value chemicals and bio-inspired nanomaterials.     

Combating biofilms

Biofilms are complex microbial communities consisting of microcolonies embedded in a matrix of self-produced polymer substances. Biofilm cells show much greater resistance to environmental challenges including antimicrobial agents than their free-living counterparts. The biofilm mode of life is believed to significantly contribute to successful microbial survival in hostile environments. Conventional treatment, disinfection and cleaning strategies do not proficiently deal with biofilm-related problems, such as persistent infections and contamination of food production facilities. In this review, strategies to control biofilms are discussed, including those of inhibition of microbial attachment, interference of biofilm structure development and differentiation, killing of biofilm cells and induction of biofilm dispersion.     

Perspectives of different colour-emissive nanomaterials in fluorescent ink,LEDs, cell imaging,and sensing of various analytes

In the past 2 decades, multicolour light-emissive nanomaterials have gained significant interest in chemical and biological sciences because of their unique optical properties. These materials have drawn much attention due to their unique characteristics towards various application fields. The development of novel nanomaterials has become the pinpoint for different application areas. In this review, the recent progress in the area of multicolour-emissive nanomaterials is summarized. The different emissions (white, orange, green, red, blue, and multicolour) of nanostructure materials (metal nanoclusters, quantum dots, carbon dots, and rare earth-based nanomaterials) are briefly discussed. The potential applications of different colour-emissive nanomaterials in the development of fluorescent inks, light-emitting diodes, cell imaging, and sensing devices are briefly summarized. Finally, the future perspectives of multicolour-emissive nanomaterials are discussed.     

Antibiofilm agents: A new perspective for antimicrobial strategy

Biofilms are complex microbial architectures that attach to surfaces and encase microorganisms in a matrix composed of self-produced hydrated extracellular polymeric substances (EPSs). In biofilms, microorganisms become much more resistant to antimicrobial treatments, harsh environmental conditions, and host immunity. Biofilm formation by microbial pathogens greatly enhances survival in hosts and causes chronic infections that result in persistent inflammation and tissue damages. Currently, it is believed over 80% of chronic infectious diseases are mediated by biofilms, and it is known that conventional antibiotic medications are inadequate at eradicating these biofilm-mediated infections. This situation demands new strategies for biofilm-associated infections, and currently, researchers focus on the development of antibiofilm agents that are specific to biofilms, but are nontoxic, because it is believed that this prevents the development of drug resistance. Here, we review the most promising antibiofilm agents undergoing intensive research and development.     

Natural products and their semi-synthetic derivatives against antimicrobial-resistant human pathogenic bacteria and fungi

Human infectious diseases caused by various microbial pathogens, in general, impact a large population of individuals every year. These microbial diseases that spread quickly remain to be a big issue in various health-related domains and to withstand the negative drug impacts, the antimicrobial-resistant pathogenic microbial organisms (pathogenic bacteria and pathogenic fungi) have developed a variety of resistance processes against many antimicrobial drug classes. During the COVID-19 outbreak, there seems to be an upsurge in drug and multidrug resistant-associated pathogenic microbial species. The preponderance of existing antimicrobials isn’t completely effective, which limits their application in clinical settings. Several naturally occurring chemicals produced from bacteria, plants, animals, marine species, and other sources are now being studied for antimicrobial characteristics. These natural antimicrobial compounds extracted from different sources have been demonstrated to be effective against a variety of diseases, although plants remain the most abundant source. These compounds have shown promise in reducing the microbial diseases linked to the development of drug tolerance and resistance. This paper offers a detailed review of some of the most vital and promising natural compounds and their derivatives against various human infectious microbial organisms. The inhibitory action of different natural antimicrobial compounds, and their possible mechanism of antimicrobial action against a range of pathogenic fungal and bacterial organisms, is provided. The review will be useful in refining current antimicrobial (antifungal and antibacterial) medicines as well as establishing new treatment strategies to tackle the rising number of human bacterial and fungal-associated infections.     

Therapeutic antimicrobial peptides may compromise natural immunity

Antimicrobial peptides (AMPs) have been proposed as a promising new class of antimicrobials despite warnings that therapeutic use could drive the evolution of pathogens resistant to our own immunity peptides. Using experimental evolution, we demonstrate that Staphylococcus aureus rapidly evolved resistance to pexiganan, a drug-candidate for diabetic leg ulcer infections. Evolved resistance was costly in terms of impaired growth rate, but costs-of-resistance were completely ameliorated by compensatory adaptation. Crucially, we show that, in some populations, experimentally evolved resistance to pexiganan provided S. aureus with cross-resistance to human-neutrophil-defensin-1, a key component of the innate immune response to infection. This unintended consequence of therapeutic use could drastically undermine our innate immune system's ability to control and clear microbial infections. Our results therefore highlight grave potential risks of AMP therapies, with implications for their development.     

工程纳米材料对污水生物处理影响的研究进展

工程纳米材料因其独特的物理化学性质被广泛应用于生产和生活中,但其潜在的风险正逐渐引起越来越多研究者的关注。目前国内外的研究主要探讨了工程纳米材料对模式微生物的毒性效应,但是对污水处理微生物的潜在影响尚缺乏系统和完整的报道。因此,本文综述了常见纳米材料对污水生物处理的影响,如碳、氮、磷的去除、甲烷化以及功能微生物种群结构演变等;同时还探讨了两种削减纳米银颗粒毒性的途径。综述内容为深入研究纳米材料对污水生物处理的潜在影响奠定了重要的理论基础。     

多孔纳米材料固定化酶研究进展

酶是一种天然生物催化剂,有催化效率高、底物选择性强和绿色环保等优点,但酶结构不稳定且重复利用率低,制约了其产业化应用。随着技术的发展,酶的固定化可以提高酶的活性和稳定性,为生物酶的工程化应用带来了新的机遇。多孔纳米材料具有比表面积大、孔隙率高、机械和化学性能稳定等特点和优异的成本效益,是理想的固定化酶载体。本文综述了近些年来金属有机框架、共价有机框架和多孔微球等纳米材料固定化酶的研究进展和应用,重点介绍了载体固定酶的方式,并总结了每种载体的特点,最后讨论了多孔纳米材料固定化酶面临的挑战和发展趋势。     

高通量测序在病原微生物耐药方面的应用进展

高通量测序是一种高效、准确、价廉的新型测序技术,随着近年来的不断推广,逐渐进入不同的研究领域。目前,多重耐药菌的感染给患者和社会增加了巨大负担,耐药机制和抗菌药物的研发是科学研究的热点之一。高通量测序技术也开始在病原微生物耐药方面发挥了巨大作用,尤其是在耐药机制研究方面,解决了一些用现有的技术无法解决的问题。本文从病原菌鉴定、耐药机制、药物新靶标、耐药菌流行病学以及用药指导等方面阐述了高通量测序在病原微生物耐药方面的应用及进展,重点讨论了耐药机制和抗菌药物新靶标进展以及现阶段存在的问题。高通量测序技术不断发展,尤其是进入病原微生物研究领域后延伸出新的研究技术和方法,随着相关的生物信息学的进步,此项技术应用将会更加广泛。     

Nanotechnology and biosensors

Nanotechnology is playing an increasingly important role in the development of biosensors. The sensitivity and performance of biosensors is being improved by using nanomaterials for their construction. The use of these nanomaterials has allowed the introduction of many new signal transduction technologies in biosensors. Because of their submicron dimensions, nanosensors, nanoprobes and other nanosystems have allowed simple and rapid analyses in vivo. Portable instruments capable of analyzing multiple components are becoming available. This work reviews the status of the various nanostructure-based biosensors. Use of the self-assembly techniques and nano-electromechanical systems (NEMS) in biosensors is discussed.     

Current developments in microbial control of insect pests and prospects for the early 21st century

The role of microbial control in crop and forest protection and the abatement of insects of medical and veterinary importance has expanded considerably with the discovery and development of new microbial control agents and genetic improvement in bacterial and viral pathogens, and improvements in formulation, application options and compatibility with other interventions. A synopsis of the literature regarding the current use of bacteria, viruses, fungi, protozoans and nematodes as microbial control agents is presented along with speculation on their potential in the early 21st century. The most widely used of all microbial control agents isBacillus thuringiensis. The isolation within the past two decades of new strains that are larvicidal for certain Diptera and Coleoptera has increased the utility of the bacterium considerably. Further improvements in efficacy and broadening of its host range are in progress with the isolation of strains with new toxins and the manipulation ofB. thuringiensis genes that encode toxin production using both recombinant and nonrecombinant methods. Genetic manipulation of these genes has also enabled their incorporation into crop plants. The development and commercial availability of entomopathogenic nematodes in the families Steinernematidae and Heterorhabditidae expands the options for the control of insects, especially those with soil inhabiting stages. The results of natural epizootics of fungi and viruses often obviate the requirement for additional interventions. Breakthroughs in understanding the genetics ofBaculovirus and subsequent gene manipulation have increased their virulence and utility. Improved production methods that utilize insect cell culture technology may enable affordable use ofBaculovirus in the not too distant future. Fungi continue to offer the only control options using entomopathogens against plant sucking insects. Although fungi have great potential for development as microbial control agents, only a few have been used on an operational scale. Some factors that might limit the full range of entomopathogen potential, including development of resistance, are discussed. Because of their selectivity and minimal environmental impact, microbial control agents will be ideal components of integrated pest management programs in the early 21st century and beyond. However, if they are used merely as replacements for chemical pesticides, then eventually these agents will face some of the same fate as the chemicals they replace, particularly with respect to resistance.