Because less than one-third of clinically relevant fusaria can be accurately identified to species level using phenotypic data (i.e., morphological species recognition), we constructed a three-locus ...DNA sequence database to facilitate molecular identification of the 69 Fusarium species associated with human or animal mycoses encountered in clinical microbiology laboratories. The database comprises partial sequences from three nuclear genes: translation elongation factor 1α (EF-1α), the largest subunit of RNA polymerase (RPB1), and the second largest subunit of RNA polymerase (RPB2). These three gene fragments can be amplified by PCR and sequenced using primers that are conserved across the phylogenetic breadth of FUSARIUM: Phylogenetic analyses of the combined data set reveal that, with the exception of two monotypic lineages, all clinically relevant fusaria are nested in one of eight variously sized and strongly supported species complexes. The monophyletic lineages have been named informally to facilitate communication of an isolate's clade membership and genetic diversity. To identify isolates to the species included within the database, partial DNA sequence data from one or more of the three genes can be used as a BLAST query against the database which is Web accessible at FUSARIUM-ID (http://isolate.fusariumdb.org) and the Centraalbureau voor Schimmelcultures (CBS-KNAW) Fungal Biodiversity Center (http://www.cbs.knaw.nl/fusarium). Alternatively, isolates can be identified via phylogenetic analysis by adding sequences of unknowns to the DNA sequence alignment, which can be downloaded from the two aforementioned websites. The utility of this database should increase significantly as members of the clinical microbiology community deposit in internationally accessible culture collections (e.g., CBS-KNAW or the Fusarium Research Center) cultures of novel mycosis-associated fusaria, along with associated, corrected sequence chromatograms and data, so that the sequence results can be verified and isolates are made available for future study.
Fusarium ranks as one of the worlds most economically destructive and species-rich groups of mycotoxigenic plant pathogens. These ubiquitous molds produce a plethora of toxic secondary metabolites, ...such as trichothecenes, zearalenone, fumonisins, and enniatins, which pose a significant threat to agricultural biosecurity, food safety, and plant, human and animal health. Fusarial-induced diseases of virtually every economically important plant cost the global agricultural economy multi-billion euro losses annually. Moreover, phylogenetically diverse fusaria, including plant pathogens, cause infections in humans, with those involving the cornea and nails being the most common.
Despite recent advances spearheaded by molecular approaches and novel technologies, species description and DNA sequence information are significantly lagging for fungi compared to many other groups ...of organisms. Large scale sequencing of vouchered herbarium material can aid in closing this gap. Here, we describe an effort to obtain broad ITS sequence coverage of the approximately 6000 macrofungal-species-rich herbarium of the Museum of Natural History in Venice, Italy. Our goals were to investigate issues related to large sequencing projects, develop heuristic methods for assessing the overall performance of such a project, and evaluate the prospects of such efforts to reduce the current gap in fungal biodiversity knowledge. The effort generated 1107 sequences submitted to GenBank, including 416 previously unrepresented taxa and 398 sequences exhibiting a best BLAST match to an unidentified environmental sequence. Specimen age and taxon affected sequencing success, and subsequent work on failed specimens showed that an ITS1 mini-barcode greatly increased sequencing success without greatly reducing the discriminating power of the barcode. Similarity comparisons and nonmetric multidimensional scaling ordinations based on pairwise distance matrices proved to be useful heuristic tools for validating the overall accuracy of specimen identifications, flagging potential misidentifications, and identifying taxa in need of additional species-level revision. Comparison of within- and among-species nucleotide variation showed a strong increase in species discriminating power at 1-2% dissimilarity, and identified potential barcoding issues (same sequence for different species and vice-versa). All sequences are linked to a vouchered specimen, and results from this study have already prompted revisions of species-sequence assignments in several taxa.
The most enigmatic aspect of the rise of
as a human pathogen is that it emerged simultaneously on three continents, with each clade being genetically distinct. Although new pathogenic fungal species ...are described regularly, these are mostly species associated with single cases in individuals who are immunosuppressed. In this study, we used phylogenetic analysis to compare the temperature susceptibility of
with those of its close relatives and to use these results to argue that it may be the first example of a new fungal disease emerging from climate change, with the caveat that many other factors may have contributed.
Plant growth–promoting bacteria show great potential for use in agriculture although efficient application remains challenging to achieve. Cells often lose viability during inoculant production and ...application, jeopardizing the efficacy of the inoculant. Since desiccation has been documented to be the primary stress factor affecting the decrease in survival, obtaining xerotolerance in plant growth–promoting bacteria is appealing. The molecular damage that occurs by drying bacteria has been broadly investigated, although a complete view is still lacking due to the complex nature of the process. Mechanic, structural, and metabolic changes that occur as a result of water depletion may potentially afflict lethal damage to membranes, DNA, and proteins. Bacteria respond to these harsh conditions by increasing production of exopolysaccharides, changing composition of the membrane, improving the stability of proteins, reducing oxidative stress, and repairing DNA damage. This review provides insight into the complex nature of desiccation stress in bacteria in order to facilitate strategic choices to improve survival and shelf life of newly developed inoculants.
Key Points
Desiccation-induced damage affects most major macromolecules in bacteria.
Most bacteria are not xerotolerant despite multiple endogenous adaption mechanisms.
Sensitivity to drying severely hampers inoculant quality.
The role of aquatic predators in controlling the anopheline aquatic stage has been known for decades. Recently, studies have highlighted that exposition to predation stress during aquatic development ...can have a profound impact on life-history traits (e.g. growth rate, fecundity and longevity) and consequently on the ability of adults to transmit human malaria parasites. In this study, we present a review aiming to contextualize the role of Anopheles larvae predators as an ecosystem factor interacting with the malaria pathogen through its vector, i.e. the female adult Anopheles. We first envisage the predator diversity that anopheline vectors are susceptible to encounter in their aquatic habitats. We then focus on mosquito-predator interactions with a special mention to anti-predator behaviors and prey adaptations developed to deal with the predation threat. Next, we address the direct and indirect effects of larval predation stress on mosquito populations and on individual life-history traits, which strongly suggest some carry-over effect of the impact of larval predation on vectorial capacity. The last part addresses the impact of human activities on larval predation. Concluding remarks highlight gaps in the knowledge of anopheline bio-ecology which may constitute avenues for researchers in the future.
► Phylogenetic analyses of RPB1 and RPB2 sequences support Fusarium monophyly. ► We resolved 20 monophyletic species complexes and nine monotypic lineages. ► Dating places the origin of Fusarium in ...the middle Cretaceous 91.3million years ago. ► Fusarium graminearum and related cereal head blight pathogens radiated in the Pleistocene. ► We dated the origin of trichothecenes, fumonisins and fusarin mycotoxins in Fusarium.
Fusarium (Hypocreales, Nectriaceae) is one of the most economically important and systematically challenging groups of mycotoxigenic phytopathogens and emergent human pathogens. We conducted maximum likelihood (ML), maximum parsimony (MP) and Bayesian (B) analyses on partial DNA-directed RNA polymerase II largest (RPB1) and second largest subunit (RPB2) nucleotide sequences of 93 fusaria to infer the first comprehensive and well-supported phylogenetic hypothesis of evolutionary relationships within the genus and 20 of its near relatives. Our analyses revealed that Cylindrocarpon formed a basal monophyletic sister to a ‘terminal Fusarium clade’ (TFC) comprising 20 strongly supported species complexes and nine monotypic lineages, which we provisionally recognize as Fusarium (hypothesis F1). The basal-most divergences within the TFC were only significantly supported by Bayesian posterior probabilities (B-PP 0.99–1). An internode of the remaining TFC, however, was strongly supported by MP and ML bootstrapping and B-PP (hypothesis F2). Analysis of seven Fusarium genome sequences and Southern analysis of fusaria elucidated the distribution of genes required for synthesis of 26 families of secondary metabolites within the phylogenetic framework. Diversification time estimates date the origin of the TFC to the middle Cretaceous 91.3million years ago. We also dated the origin of several agriculturally important secondary metabolites as well as the lineage responsible for Fusarium head blight of cereals. Dating of several plant-associated species complexes suggests their evolution may have been driven by angiosperm diversification during the Miocene. Our results support two competing hypotheses for the circumscription of Fusarium and provide a framework for future comparative phylogenetic and genomic analyses of this agronomically and medically important genus.
The paucity of fungal diseases in mammals relative to insects, amphibians, and plants is puzzling. We analyzed the thermal tolerance of 4802 fungal strains from 144 genera and found that most cannot ...grow at mammalian temperatures. Fungi from insects and mammals had greater thermal tolerances than did isolates from soils and plants. Every 1°C increase in the 30°C–40°C range excluded an additional 6% of fungal isolates, implying that fever could significantly increase the thermal exclusion zone. Mammalian endothermy and homeothermy are potent nonspecific defenses against most fungi that could have provided a strong evolutionary survival advantage against fungal diseases
Molecular platforms are regarded as promising candidates in the generation of units of information for quantum computing. Herein, a strategy combining spin‐crossover metal ions and radical ligands is ...proposed from a model Hamiltonian first restricted to exchange interactions. Unusual spin states structures emerge from the linkage of a singlet/triplet commutable metal centre with two doublet‐radical ligands. The ground state nature is modulated by charge transfers and can exhibit a mixture of triplet and singlet local metal spin states. Besides, the superposition reaches a maximum for
2KM=K1+K2
${2{K}_{M}={K}_{1}+{K}_{2}}$
, suggesting a necessary competition between the intramolecular
KM
${{K}_{M}}$
and inter‐metal‐ligand
K1
${{K}_{1}}$
and
K2
${{K}_{2}}$
direct exchange interactions. The results promote spinmerism, an original manifestation of quantum entanglement between the spin states of a metal centre and radical ligands. The study provides insights into spin‐coupled compounds and inspiration for the development of molecular spin‐qubits.
Molecular magnetism architectures based on spin‐crossover metal ion and radical ligands produce total spin states S characterised by entangled local spin states. Conditions on a parametrised Hamiltonian are derived for molecular spin‐qubits applications.
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