Photodynamic antimicrobial therapy

Photodynamic antimicrobial therapy (PACT) involves the utilisation of photosensitizers activated by exposure to visible light in order to eradicate microbes (this method has already been applied in photodynamic therapy of tumours). Photodynamic effect of the particular photosensitive substance (PS) is attributed to its ability to penetrate susceptible microorganisms, to absorb the light of certain wavelength, and to generate reactive cytotoxic oxygen products. The target microorganisms for photoinactivation are bacteria, fungi, viruses and protozoa. Photodynamic antimicrobial therapy is proposed as a potentially topical, non-invasive approach suitable for treatment of locally occurring infection. The fact that bacteria are becoming increasingly resistant to antibiotics and antiseptics has lead to an increased interest in the development of new alternative eradication methods, such as PACT. Research and development of photosensitive substances are aimed at finding effective antimicrobial substances, which would have a broad-spectrum potency.     

抗菌光敏剂的分类及研究进展

目前控制细菌和病毒感染性疾病的方法很多,但由于微生物菌株种类越来越多,且耐药微生物菌株不断涌现,已有的治疗手段无法取得良好疗效,因此探索新的抗微生物治疗方法迫在眉睫。光动力抗菌化学疗法是基于光动力疗法的原理,利用光敏剂在异常组织选择性聚集,在分子氧的参与下,由特定波长的光激发产生活性氧,引发一系列的光化学反应,对微生物进行选择性杀伤的一种新方法。光动力抗菌化学疗法对细菌、真菌和病毒引起的感染,特别是耐药菌感染均显示很好的疗效。本文将对光动力抗菌化学疗法中常使用的光敏剂进行分类,并对其研究进展进行综述。     

The photodynamic effect of methylene blue and toluidine blue on <Emphasis Type="Italic">Candida albicans</Emphasis> is dependent on medium conditions

Due to the increased number of immunocompromised patients, the infections associated with the pathogen of the genus Candida and other fungi have increased dramatically. Photodynamic antimicrobial chemotherapy (PACT) has been presented as a potential antimicrobial therapy, in a process that combines light and a photosensitizing drug, which promotes a phototoxic response by the treated cells. In this work, we studied the effects of the different medium conditions during PACT, using either methylene blue (MB) or toluidine blue (TB) on Candida albicans. The inhibition of the growth produced by PACT was decreased for different pH values (6.0, 7.0, and 8.0) in a buffered medium. The phototoxic effects were observed only in the presence of saline (not buffered medium). PACT was modulated by calcium in a different manner using either MB or TB. Also when using MB both verapamil or sodium azide were able to decrease the phototoxic effects on the C. albicans. These results show that PACT is presented as a new and promising antifungal therapy, however, new studies are necessary to understand the mechanism by which this event occurs.     

Cryptococcus neoformans: the yeast that likes it hot

The ability of fungi to grow well at mammalian body temperatures is a fundamental characteristic of invasive human fungal pathogens. Cryptococcus neoformans, with its genetics, molecular biology, robust animal models and clinical importance, has become a premier fungal model system for molecular fungal pathogenesis studies. There has been over a half century of study into how C. neoformans grows at high temperatures. However, recently the understanding of high-temperature growth at a molecular level has dramatically accelerated. Many strategies have been used to identify genes and over a dozen genes have already been identified to be necessary for high-temperature growth. It is likely that there are many more to discover. It is clear that, as further studies understand how this encapsulated yeast is able to withstand the stresses of high temperature at a genetic and molecular basis, we will also know more about how it and other fungal pathogens have evolved into well-established human pathogens.     

一株产紫杉醇内生真菌液体发酵工艺的优化

紫杉醇是一种高效、低毒、广谱的天然抗癌药物,可以有效地治疗乳腺癌、子宫癌等。近年来的研究发现,从植物内生真菌中发酵生产紫杉醇被证明是解决药源问题的有效途径。从分离到的420株内生真菌中筛选到一株产紫杉醇的内生真菌XC1-07为实验材料进行发酵条件的初步优化。结果表明：最适碳源、氮源分别是麦芽糖和NH4NO3;在含10g/L NH4NO3、90g/L麦芽糖、1.0g/L MgSO4、pH6的优化培养基中培养13d,紫杉醇的产量为1,124.34μg/L。为目前报道的植物内生真菌发酵生产紫杉醇最高的产量。     

Production of cross-kingdom oxylipins by pathogenic fungi: An update on their role in development and pathogenicity

Oxylipins are a class of molecules derived from the incorporation of oxygen into polyunsaturated fatty acid substrates through the action of oxygenases. While extensively investigated in the context of mammalian immune responses, over the last decade it has become apparent that oxylipins are a common means of communication among and between plants, animals, and fungi to control development and alter hostmicrobe interactions. In fungi, some oxylipins are derived nonenzymatically while others are produced by lipoxygenases, cyclooxygenases, and monooxygenases with homology to plant and human enzymes. Recent investigations of numerous plant and human fungal pathogens have revealed oxylipins to be involved in the establishment and progression of disease. This review highlights oxylipin production by pathogenic fungi and their role in fungal development and pathogen/host interactions.     

Studies on diversity of higher fungi in Yunnan,southwestern China: A review

Yunnan is exceedingly rich in higher fungi (Ascomycota and Basidiomycota). Given that the number of fungi (including lichens) occurring in a given area is, as Hawksworth suggested, roughly six times that of local vascular plants, a total of approximately 104,000 fungal species would be expected in Yunnan. However, to date only about 6000 fungal species, including roughly 3000 species of higher fungi, have been reported from the province. Although studies on Yunnan's fungi started in the late nineteenth century, significant progress has been made only in the last forty-five years. Over the first twenty-five years of this period, studies on fungal diversity in this area have largely been about taxonomy based on morphological characters and partially on geographical distribution. Over the past twenty years, the combination of both morphological and molecular phylogenetic approaches has become the preferred method to help understand the diversity and evolution of higher fungi. This review focuses on our current knowledge of how geological, geographical, and ecological factors may have contributed to the diversity patterns of higher fungi in Yunnan. Based on this knowledge, three aspects for future studies are suggested.     

Lipopolysaccharide neutralizing Peptide-porphyrin conjugates for effective photoinactivation and intracellular imaging of gram-negative bacteria strains

A simple and specific strategy based on the bioconjugation of a photosensitizer protophophyrin IX (PpIX) with a lipopolysaccharide (LPS) binding antimicrobial peptide YI13WF (YVLWKRKRKFCFI-Amide) has been developed for the effective fluorescent imaging and photodynamic inactivation of Gram-negative bacterial strains. The intracellular fluorescent imaging and photodynamic antimicrobial chemotherapy (PACT) studies supported our hypothesis that the PpIX-YI13WF conjugates could serve as efficient probes to image the bacterial strains and meanwhile indicated the potent activities against Gram-negative bacterial pathogens especially for those with antibiotics resistance when exposed to the white light irradiation. Compared to the monomeric PpIX-YI13WF conjugate, the dimeric conjugate indicated the stronger fluorescent imaging signals and higher photoinactivation toward the Gram-negative bacterial pathogens throughout the whole concentration range. In addition, the photodynamic bacterial inactivation also demonstrated more potent activity than the minimum inhibitory concentration (MIC) values of dimeric PpIX-YI13WF conjugate itself observed for E. coli DH5a (～4 times), S. enterica (～8 times), and other Gram-negative strains including antibiotic-resistant E. coli BL21 (～8 times) and K. pneumoniae (～16 times). Moreover, both fluorescent imaging and photoinactivation measurements also demonstrated that the dimeric PpIX-YI13WF conjugate could selectively recognize bacterial strains over mammalian cells and generate less photo damage to mammalian cells. We believed that the enhanced fluorescence and bacterial inactivation were probably attributed to the higher binding affinity between dimeric photosensitizer peptide conjugate and LPS components on the surface of bacterial strains, which were the results of efficient multivalent interactions.     

Photodynamic Antifungal Therapy Against Chromoblastomycosis

Photodynamic therapy (PDT) is a minimally invasive approach, in which a photosensitizer compound is activated by exposure to light. The activation of the sensitizer drug results in several chemical reactions, such as the production of reactive oxygen species and other reactive molecules, which presence in the biological site leads to the damage of target cells. Although PDT has been primarily developed to combat cancerous lesions, this therapy can be employed for the treatment of several conditions, including infectious diseases. A wide range of microorganisms, including Gram-positive and Gram-negative bacteria, viruses, protozoa, and fungi, have demonstrated susceptibility to antimicrobial PDT. This treatment might consist in an alternative for the management of fungal infections. Antifungal photodynamic therapy has been successfully employed against Candida species, dermatophytes, and Aspergillus niger. Chromoblastomycosis is an infection that involves skin and subcutaneous tissues caused by the traumatic inoculation of dematiaceous fungi species, being that the most prevalent are Fonsecaea pedrosoi and Claphialophora carrionii. In the present work, the clinical applications of PDT for the treatment of chromoblastomycosis are evaluated. We have employed methylene blue as photosensitizer and a LED (Light Emitting Diode) device as light source. The results of this treatment are positive, denoting the efficacy of PDT against chromoblastomycosis. Considering that great part of the published works are focused on in vitro trials, these clinical tests can be considered a relevant source of information about antifungal PDT, since its results have demonstrated to be promising. The perspectives of this kind of treatment are analyzed in agreement with the recent literature involving antifungal PDT.     

Fungal adaptation to the mammalian host: it is a new world, after all

Adaptation to environmental conditions is key to fungal survival during infection of human hosts. Although the host immune system is often considered the primary obstacle to fungal colonization, invading fungi must also contend with extreme abiotic stresses. Recent work with human pathogenic fungi has uncovered systems for detecting and responding to changes in temperature, carbon source, metal ion availability, pH, and gas tension. These systems play a major role in adaptation to the host niche and are essential factors for persistence in a mammalian host. Future investigations into fungal responses to these and other abiotic components of the host environment have the potential to uncover novel targets for anti-fungal therapy.     

Genotypic analysis of variability in Zygomycetes. A mini-review

Different types of molecular markers are available for use in evolutionary and population studies of microscopic fungi. These approaches have proved their merits and have been successfully applied to a wide range of fungal species belonging in the Ascomycetes and Basidiomycetes. Species in the class Zygomycetes have been rather neglected from this aspect. This review discusses the information available from investigations of the genotypic variability in this group of fungi.     

Biosynthesis of fungal melanins and their importance for human pathogenic fungi

For more than 40 years fungi have been known to produce pigments known as melanins. Predominantly these have been dihydroxyphenylalanine (DOPA)-melanin and dihydroxynaphthalene (DHN)-melanin. The biochemical and genetical analysis of the biosynthesis pathways have led to the identification of the genes and corresponding enzymes of the pathways. Only recently have both these types of melanin been linked to virulence in some human pathogenic and phytopathogenic fungi. The absence of melanin in human pathogenic and phytopathogenic fungi often leads to a decrease in virulence. In phytopathogenic fungi such as Magnaporthe grisea and Colletotrichum lagenarium, besides other possible functions in pathogenicity, DHN-melanin plays an essential role in generating turgor for plant appressoria to penetrate plant leaves. While the function of melanin in human pathogenic fungi such as Cryptococcus neoformans, Wangiella dermatitidis, Sporothrix schenckii, and Aspergillus fumigatus is less well defined, its role in protecting fungal cells has clearly been shown. Specifically, the ability of both DOPA- and DHN-melanins to quench free radicals is thought to be an important factor in virulence. In addition, in several fungi the production of fungal virulence factors, such as melanin, has been linked to a cAMP-dependent signaling pathway. Many of the components involved in the signaling pathway have been identified.     

真菌系统学大趋势：越来越多的分类单元

分子生物学技术与真菌系统学的有机融合,为真菌分类和系统发育研究带来了革命性的变化。最近20年来,真菌学家们建立了大量的新目、新科、新属和新种,掀开了真菌多样性及其起源进化研究的新纪元,但很多重要的系统发育问题仍没有解决,特别是大量目间、科间的亲缘关系并不清楚。细分是真菌系统学的主流趋势,野生食用菌和毒蘑菇的分类也是如此,近年涌现了越来越多的新分类单元,如在2010-2019年的10年间,中国发表大型真菌（含地衣）新种1 240余个。本专刊收载的15篇论文是对我国野生食用菌和毒蘑菇研究工作的部分总结,对真菌资源利用、毒蘑菇中毒预防与治疗具有较重要的科学意义和应用价值。     

Detection and identification of fungal species by electronic nose technology: A systematic review

A rapid and effective identification of fungal species is essential for numerous applications, and electronic nose systems are being proposed as suitable alternatives to currently available fungi identification techniques. Hence, the present review aims to unveil all published information concerning fungi identification by electronic nose systems.A systematic review of the literature was conducted according to the PRISMA guidelines. A total of 16 articles met the inclusion criteria and were included in the analysis. The results of the reviewed studies demonstrated that effective detection of fungi was possible through sensor-based electronic nose systems, which may actually function as a mycotoxin screening tool for several applications.The obtained results suggest that the sensor-based electronic nose systems may not only screen different fungi genera, but also identify the associated species. This technology has already been experimented in several fields, from food industry to clinical practice.By summarizing these results, the present review may accelerate the standardization of electronic noses in fungi detection and discrimination, allowing a faster and more efficient screening of samples.     

MicroRNA-122 Inhibits the Production of Inflammatory Cytokines by Targeting the PKR Activator PACT in Human Hepatic Stellate Cells

MicroRNA-122 (miR-122) is one of the most abundant miRs in the liver. Previous studies have demonstrated that miR-122 plays a role in inflammation in the liver and functions in hepatic stellate cells (HSCs), which reside in the space of Disse. Here, we showed that the transient inhibition of PKR-activating protein (PACT) expression, by miR-122 or siRNA targeting of PACT, suppressed the production of proinflammatory cytokines, such as interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1) and IL-1β, in human HSC LX-2. Sequence and functional analyses confirmed that miR-122 directly targeted the 3′-untranslated region of PACT. Immunofluorescence analysis revealed that miR-122 blocked NF-κB-nuclear translocation in LX-2 cells. We also showed that conditioned medium from miR-122-transfected LX-2 cells suppressed human monocyte-derived THP-1 cell migration. Taken together, our study indicates that miR-122 may downregulate cytokine production in HSCs and macrophage chemotaxis and that the targeting of miR-122 may have therapeutic potential for preventing the progression of liver diseases.     

Vacuoles and fungal biology

Fungal vacuoles have long been recognised as versatile organelles, involved in many aspects of protein turnover, cellular homeostasis, membrane trafficking, signalling and nutrition. Recent research has also revealed an expanding repertoire of physiological functions for fungal vacuoles that are vital for fungal growth, differentiation, symbiosis and pathogenesis. Vacuole-mediated long-distance nutrient transporting systems have been shown to facilitate mycelial foraging and long-distance communication in saprophytes and mycorrhizal fungi. Some hyphae of plant and human fungal pathogens can grow under severely nutrient-limited conditions by expanding the vacuolar space rather than synthesising new cytoplasm and organelles. Autophagy has been recognised as a crucial process in plant pathogens for the initiation of appressorium formation. These studies demonstrate the importance of fungal vacuoles as organelles that are essential for many of the attributes that define the activities and roles of fungi in their natural environments.     

真菌DNA条形码研究进展

DNA条形码（DNA barcode）是通过一段短的标准DNA片段实现物种的快速、准确和标准化鉴定。线粒体细胞色素C氧化酶亚基I（COI）基因作为动物的DNA条形码已广泛应用于物种鉴定中,在植物上已选定叶绿体rbcL和matK基因作为基本的DNA条形码。目前世界各国真菌学家正对不同的真菌类群进行不同基因片段的筛选与评价,并在第四届国际生命条形码大会上正式推荐了ITS作为真菌的首选DNA条形码。对国内外真菌DNA条形码的研究进展进行总结与分析,并展望真菌DNA条形码的应用前景。     

Of patterns and pathways: microarray technologies for the analysis of filamentous fungi

During recent years, microarrays have been firmly established as valuable tools for the discovery of novel biological phenomena. Especially in combination with whole genome sequences, microarray data can help unravel the dynamics of the expressed genome. For filamentous fungi, microarray studies have already been performed with more than 20 different species; these investigations have explored a variety of different aspects of fungal biology. In this review, I will give an overview of some of the key questions that have been addressed using microarray hybridizations with filamentous fungi, with particular focus on the analysis of co-regulated pathways and physically clustered genes, as well as on the use of microarray data to determine a molecular phenotype. Additionally, a number of useful, freely available software tools for the analysis of fungal microarray data will be discussed.     

Causes and consequences of changes to New Zealand?s fungal biota

This paper briefly reviews advances in knowledge of the non-lichenised fungi of New Zealand over the past 25 years. Since 1980, the number of species recorded from New Zealand has doubled, and molecular techniques have revolutionised studies on fungal phylogeny and our understanding of fungal distribution, biology and origins. The origins of New Zealand?s fungi are diverse; a few appear to be ancient, whereas many have arrived in geologically more recent times following trans-oceanic dispersal. Some of these more recent arrivals have evolved subsequently to form local endemic species, while others may be part of larger populations maintained through regular, trans-oceanic gene flow. Although questions remain about which fungi truly are indigenous and which are exotic, about one-third of the fungi recorded from New Zealand are likely to have been introduced since human settlement. While most exotic species are confined to human-modified habitats, there are some exceptions. These include species with potential to have significant impacts at the landscape scale. Examples from saprobic, pathogenic, endophytic and ectomycorrhizal fungi are used to discuss the factors driving the distribution and dispersal of New Zealand?s fungi at both global and local scales, the impact that historical changes to New Zealand?s vascular plant and animal biota have had on indigenous fungi, and the broader ecological impact of some of the exotic fungal species that have become naturalised in native habitats. The kinds of fungi present in New Zealand, and the factors driving the distribution and behaviour of those fungi, are constantly changing. These changes have occurred over a wide scale, in both time and space, which means New Zealand?s indigenous fungi evolved in response to ecological pressures very different from those found in New Zealand today.