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Biotechnology Advances 2018Aspergillus is a fungal genus comprising several hundred species, many of which can damage the health of plants, animals and humans by direct infection and/or due to the... (Review)
Review
Aspergillus is a fungal genus comprising several hundred species, many of which can damage the health of plants, animals and humans by direct infection and/or due to the production of toxic secondary metabolites known as mycotoxins. Aspergillus-specific antibodies have been generated against polypeptides, polysaccharides and secondary metabolites found in the cell wall or secretions, and these can be used to detect and monitor infections or to quantify mycotoxin contamination in food and feed. However, most Aspergillus-specific antibodies are generated against heterogeneous antigen preparations and the specific target remains unknown. Target identification is important because this can help to characterize fungal morphology, confirm host penetration by opportunistic pathogens, detect specific disease-related biomarkers, identify new candidate targets for antifungal drug design, and qualify antibodies for diagnostic and therapeutic applications. In this review, we discuss how antibodies are raised against heterogeneous Aspergillus antigen preparations and how they can be characterized, focusing on strategies to identify their specific antigens and epitopes. We also discuss the therapeutic, diagnostic and biotechnological applications of Aspergillus-specific antibodies.
Topics: Animals; Antibodies, Fungal; Antigens, Fungal; Aspergillus; Biotechnology; Humans; Mice; Rats
PubMed: 29608951
DOI: 10.1016/j.biotechadv.2018.03.016 -
Medical Mycology 2009Aspergillus terreus can cause invasive infections in humans, which are often refractory to therapy with the antifungal drug amphotericin B and have a propensity to... (Review)
Review
Aspergillus terreus can cause invasive infections in humans, which are often refractory to therapy with the antifungal drug amphotericin B and have a propensity to dissemination. The organism has diverse colony morphology, and sub-typing studies have demonstrated that isolates of A. terreus are diverse in their genotypes. However, detailed phylogenetic studies of section Terrei employing sequence information from protein coding regions have not been thus far attempted. Interestingly, A. terreus produces unicellular forms called accessory conidia in vitro and during infection; the clinical relevance of these structures are not well understood. This paper presents an overview of the morphology, species identification strategies, and molecular epidemiology of A. terreus.
Topics: Aspergillosis; Aspergillus; DNA Fingerprinting; DNA, Fungal; Humans; Molecular Epidemiology; Mycological Typing Techniques
PubMed: 19291598
DOI: 10.1080/13693780802562092 -
Journal of Medical and Veterinary... 1992
Review
Topics: Animals; Aspergillosis; Aspergillus; Cattle; Cattle Diseases; Endopeptidases; Iron; Lipid Metabolism; Virulence
PubMed: 1474459
DOI: No ID Found -
Advances in Experimental Medicine and... 2016The biofilm phenotype of Aspergillus species is an important and accepted clinical entity. While industrially these biofilms have been used extensively in important... (Review)
Review
The biofilm phenotype of Aspergillus species is an important and accepted clinical entity. While industrially these biofilms have been used extensively in important biofermentations, their role in clinical infection is less well defined. A recent flurry of activity has demonstrated that these interesting filamentous moulds have the capacity to form biofilms both in vitro and in vivo, and through various investigations have shown that these are exquisitely resistant to antifungal therapies through a range of adaptive resistance mechanisms independent of defined genetic changes. This review will explore the clinical importance of these biofilms and provide contemporary information with respect to their clinical management.
Topics: Antifungal Agents; Aspergillosis; Aspergillus; Biofilms; Humans
PubMed: 27271678
DOI: 10.1007/5584_2016_4 -
Mycopathologia Dec 2014The genus Aspergillus is one of the most widespread groups of fungi on Earth, comprised of about 300-350 species with very diverse lifestyles. Most species produce... (Review)
Review
The genus Aspergillus is one of the most widespread groups of fungi on Earth, comprised of about 300-350 species with very diverse lifestyles. Most species produce asexual propagula (conidia) on conidial heads. Despite their ubiquity, a sexual cycle has not yet been identified for most of the aspergilli. Where sexual reproduction is present, species exhibit either homothallic (self fertile) or heterothallic (obligate outcrossing) breeding systems. A parasexual cycle has also been described in some Aspergillus species. As in other fungi, sexual reproduction is governed by mating-type (MAT) genes, which determine sexual identity and are involved in regulating later stages of sexual development. Previous population genetic studies have indicated that some supposedly asexual aspergilli exhibit evidence of a recombining population structure, suggesting the presence of a cryptic sexual cycle. In addition, genome analyses have revealed networks of genes necessary for sexual reproduction in several Aspergillus species, again consistent with latent sexuality in these fungi. Knowledge of MAT gene presence has then successfully been applied to induce sexual reproduction between MAT1-1 and MAT1-2 isolates of certain supposedly asexual aspergilli. Recent progress in understanding the extent and significance of sexual reproduction is described here, with special emphasis on findings that are relevant to clinically important aspergilli.
Topics: Aspergillus; Cell Cycle; Crossing Over, Genetic; Genes, Mating Type, Fungal
PubMed: 25118872
DOI: 10.1007/s11046-014-9795-8 -
Clinical Microbiology and Infection :... Aug 2016The use of multi-locus DNA sequence analysis has led to the description of previously unknown 'cryptic' Aspergillus species, whereas classical morphology-based... (Review)
Review
The use of multi-locus DNA sequence analysis has led to the description of previously unknown 'cryptic' Aspergillus species, whereas classical morphology-based identification of Aspergillus remains limited to the section or species-complex level. The current literature highlights two main features concerning these 'cryptic' Aspergillus species. First, the prevalence of such species in clinical samples is relatively high compared with emergent filamentous fungal taxa such as Mucorales, Scedosporium or Fusarium. Second, it is clearly important to identify these species in the clinical laboratory because of the high frequency of antifungal drug-resistant isolates of such Aspergillus species. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been shown to enable the identification of filamentous fungi with an accuracy similar to that of DNA sequence-based methods. As MALDI-TOF MS is well suited to the routine clinical laboratory workflow, it facilitates the identification of these 'cryptic' Aspergillus species at the routine mycology bench. The rapid establishment of enhanced filamentous fungi identification facilities will lead to a better understanding of the epidemiology and clinical importance of these emerging Aspergillus species. Based on routine MALDI-TOF MS-based identification results, we provide original insights into the key interpretation issues of a positive Aspergillus culture from a clinical sample. Which ubiquitous species that are frequently isolated from air samples are rarely involved in human invasive disease? Can both the species and the type of biological sample indicate Aspergillus carriage, colonization or infection in a patient? Highly accurate routine filamentous fungi identification is central to enhance the understanding of these previously unknown Aspergillus species, with a vital impact on further improved patient care.
Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus; Drug Resistance, Fungal; Genes, Fungal; Humans; Microbial Sensitivity Tests; Multilocus Sequence Typing; Population Surveillance; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 27263029
DOI: 10.1016/j.cmi.2016.05.013 -
Medical Mycology Journal 2011
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Applied Microbiology and Biotechnology Oct 2015Isolates of Aspergillus species are able to produce a large number of secondary metabolites. The profiles of biosynthetic families of secondary metabolites are species... (Review)
Review
Isolates of Aspergillus species are able to produce a large number of secondary metabolites. The profiles of biosynthetic families of secondary metabolites are species specific, whereas individual secondary metabolite families can occur in other species, even those phylogenetically and ecologically unrelated to Aspergillus. Furthermore, there is a high degree of chemo-consistency from isolate to isolate in a species even though certain metabolite gene clusters are silenced in some isolates. Genome sequencing projects have shown that the diversity of secondary metabolites is much larger in each species than previously thought. The potential of finding even further new bioactive drug candidates in Aspergillus is evident, despite the fact that many secondary metabolites have already been structure elucidated and chemotaxonomic studies have shown that many new secondary metabolites have yet to be characterized. The genus Aspergillus is cladistically holophyletic but phenotypically polythetic and very diverse and is associated to quite different sexual states. Following the one fungus one name system, the genus Aspergillus is restricted to a holophyletic clade that include the morphologically different genera Aspergillus, Dichotomomyces, Phialosimplex, Polypaecilum and Cristaspora. Secondary metabolites common between the subgenera and sections of Aspergillus are surprisingly few, but many metabolites are common to a majority of species within the sections. We call small molecule extrolites in the same biosynthetic family isoextrolites. However, it appears that secondary metabolites from one Aspergillus section have analogous metabolites in other sections (here also called heteroisoextrolites). In this review, we give a genus-wide overview of secondary metabolite production in Aspergillus species. Extrolites appear to have evolved because of ecological challenges rather than being inherited from ancestral species, at least when comparing the species in the different sections of Aspergillus. Within the Aspergillus sections, secondary metabolite pathways seem to inherit from ancestral species, but the profiles of these secondary metabolites are shaped by the biotic and abiotic environment. We hypothesize that many new and unique section-specific small molecule extrolites in each of the Aspergillus will be discovered.
Topics: Aspergillus; Biodiversity; Molecular Sequence Data; Phylogeny
PubMed: 26243055
DOI: 10.1007/s00253-015-6839-z -
Medical Mycology 2009Aspergillus is a genus of molds named after the morphological structure that bears asexual spores, the aspergillum, which resembles a liturgical device. This genus... (Review)
Review
Aspergillus is a genus of molds named after the morphological structure that bears asexual spores, the aspergillum, which resembles a liturgical device. This genus contains several species of positive or negative economic importance in industry, agriculture and medicine. The majority of aspergilli, including most species of economic importance, are known to reproduce only by asexual spores. Genome projects have been completed for A. fumigatus, A. nidulans, A. niger and A. oryzae; several other species are also being sequenced. The data from these genome projects have been useful in elucidating aspects of phylogeny, the evolution of sexuality and the extent of secondary metabolite diversity. To date, however, the impact on drug discovery, diagnosis of aspergillosis, and our understanding of fungal pathogenesis has been less pronounced.
Topics: Aspergillosis; Aspergillus; Humans; Virulence
PubMed: 19253144
DOI: 10.1080/13693780802712515 -
Medical Mycology Jan 2018Cryptic species in Aspergillus section Fumigati are increasingly recognised as pathogens in humans and animals. The A. viridinutans complex (AVC) has recently expanded... (Review)
Review
Cryptic species in Aspergillus section Fumigati are increasingly recognised as pathogens in humans and animals. The A. viridinutans complex (AVC) has recently expanded to comprise 10 species, of which six are known to be pathogenic, including A. udagawae, A. felis, A. pseudofelis, A. parafelis, A. pseudoviridinutans, and A. wyomingensis. They cause locally invasive and disseminated invasive disease syndromes, including chronic pulmonary aspergillosis and invasive aspergillosis in humans, invasive fungal rhinosinusitis in cats, and disseminated invasive aspergillosis in dogs. In contrast to A. fumigatus, AVC species are characterized by higher minimum inhibitory concentrations (MICs) of antifungal drugs and the infections they cause are typically more chronic and more refractory to therapy. This review, of relevance for one-health practitioners, explores the history of the AVC as well as current phylogenetic relationships, secondary metabolite production, environmental distribution, clinical syndromes, and antifungal susceptibility patterns.
Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus; Humans; Microbial Sensitivity Tests; One Health
PubMed: 28379569
DOI: 10.1093/mmy/myx016