202 research outputs found
Thecaphora capensis sp. nov., an unusual new anther smut on Oxalis in South Africa
The smut genus Thecaphora contains plant parasitic microfungi that typically infect very specific plant organs. In this study, we describe a new species of Thecaphora from Oxalis lanata var. rosea (Oxalidaceae) in the Cape Floristic Region of South Africa. Molecular phylogenetic reconstructions based on large subunit ribosomal DNA sequence data confirmed the generic placement of the fungus and confirmed that it represents an undescribed species for which the name T. capensis sp. nov. is provided. The closest known sister species of the new taxon is T. oxalidis that infects the fruits of Oxalis spp. in Europe, Asia and the Americas. In contrast, T. capensis produces teliospores within the anthers of its host. This is the first documented case of an anther-smut from an African species of Oxalis and the first Thecaphora species described from Africa
Ravenelia piepenbringiae and Ravenelia hernandezii, two new rust species on Senegalia (Fabaceae, Mimosoideae) from Panama and Costa Rica
Two new rust species, Ravenelia piepenbringiae and R. hernandezii (Pucciniales) on Senegalia spp. (Fabaceae) are described from the Neotropics (Panama, Costa Rica). A key to the species on neotropical Senegalia spp. is provided. Molecular phylogenetic analyses based on 28S rDNA sequence data suggest that the representatives of Senegalia rusts distributed in the neotropics evolved independently from species known from South Africa. This is further supported by the teliospore morphology, which is characterised by uniseriate cysts in the neotropical Senegalia rusts and contrasting multiseriate cysts in the paleotropic Ravenelia species that infect this host genus
Comparison of denitrification induced by various organic substances - reaction rates, microbiology and temperature effect
Widespread groundwater pollution with nitrate (NO3â) and the finite and decreasing geogenic NO3â degradation capacity in aquifers require a better understanding of potential treatment methods. This project aimed at exploring and comparing the efficiency of four organic substances as electron donors for heterotrophic denitrification. Circulation column experiments using sediment without NO3â degradation capacity and high agricultural NO3â groundwater were conducted. Acetate, glucose, ascorbic acid, and ethanol were added to these columns in three concentration steps to induce biological denitrification, whereby also temperature dependence of denitrification rates (room temperature and typical groundwater temperature of 10°C) was taken into account. Results show denitrification with all four carbon (C) sources with intensities varying considerably between electron donors. Comparison of the two temperature approaches shows substantial differences between applied organic substances and indicates T as an important variable for denitrification. Ethanol is clearly the most effective electron donor for biodenitrification in groundwater investigated in this study, with a stronger and more effective NO3â degradation at 10°C than at room temperature. In contrast, much higher reaction rates are achieved with glucose at room temperature, compared to 10°C. Denitrification with ascorbic acid is very low at both temperatures; its addition produces biomass which repeatedly led to column clogging. In the entire test series, nitrite (NO2â) accumulation occurred more frequently and in higher concentrations at 10°C. Analysis of microorganisms shows a strong modification in microbial community in reaction to the addition of different organic C as well as between the two temperature approaches
Notes, outline and divergence times of Basidiomycota
The Basidiomycota constitutes a major phylum of the kingdom Fungi and is second in species numbers to the Ascomycota. The present work provides an overview of all validly published, currently used basidiomycete genera to date in a single document. An outline of all genera of Basidiomycota is provided, which includes 1928 currently used genera names, with 1263 synonyms, which are distributed in 241 families, 68 orders, 18 classes and four subphyla. We provide brief notes for each accepted genus including information on classification, number of accepted species, type species, life mode, habitat, distribution, and sequence information. Furthermore, three phylogenetic analyses with combined LSU, SSU, 5.8s, rpb1, rpb2, and ef1 datasets for the subphyla Agaricomycotina, Pucciniomycotina and Ustilaginomycotina are conducted, respectively. Divergence time estimates are provided to the family level with 632 species from 62 orders, 168 families and 605 genera. Our study indicates that the divergence times of the subphyla in Basidiomycota are 406-430 Mya, classes are 211-383 Mya, and orders are 99-323 Mya, which are largely consistent with previous studies. In this study, all phylogenetically supported families were dated, with the families of Agaricomycotina diverging from 27-178 Mya, Pucciniomycotina from 85-222 Mya, and Ustilaginomycotina from 79-177 Mya. Divergence times as additional criterion in ranking provide additional evidence to resolve taxonomic problems in the Basidiomycota taxonomic system, and also provide a better understanding of their phylogeny and evolution
AxPcoords & parallel AxParafit: statistical co-phylogenetic analyses on thousands of taxa
Background
Current tools for Co-phylogenetic analyses are not able to cope with the continuous accumulation of phylogenetic data. The sophisticated statistical test for host-parasite co-phylogenetic analyses implemented in Parafit does not allow it to handle large datasets in reasonable times. The Parafit and DistPCoA programs are the by far most compute-intensive components of the Parafit analysis pipeline. We present AxParafit and AxPcoords (Ax stands for Accelerated) which are highly optimized versions of Parafit and DistPCoA respectively.
Results
Both programs have been entirely re-written in C. Via optimization of the algorithm and the C code as well as integration of highly tuned BLAS and LAPACK methods AxParafit runs 5â61 times faster than Parafit with a lower memory footprint (up to 35% reduction) while the performance benefit increases with growing dataset size. The MPI-based parallel implementation of AxParafit shows good scalability on up to 128 processors, even on medium-sized datasets. The parallel analysis with AxParafit on 128 CPUs for a medium-sized dataset with an 512 by 512 association matrix is more than 1,200/128 times faster per processor than the sequential Parafit run. AxPcoords is 8â26 times faster than DistPCoA and numerically stable on large datasets. We outline the substantial benefits of using parallel AxParafit by example of a large-scale empirical study on smut fungi and their host plants. To the best of our knowledge, this study represents the largest co-phylogenetic analysis to date.
Conclusion
The highly efficient AxPcoords and AxParafit programs allow for large-scale co-phylogenetic analyses on several thousands of taxa for the first time. In addition, AxParafit and AxPcoords have been integrated into the easy-to-use CopyCat tool
Author Correction: identification of fungal lignocellulose-degrading biocatalysts secreted by Phanerochaete chrysosporium via activity-based protein profiling
Correction to: Communications Biology https://doi.org/10.1038/s42003-022-04141-x, published online 16 November 2022.In the original version of the Article, an incorrect additional description of panel b in Figure 1 was included. The following sentence has now been removed:b Lignocellulose is a complex and recalcitrant polymer built up from cellulose, xylan (hemicellulose), and lignin. Its degradation requires the synergistic action of various different enzymes.Bio-organic Synthesi
Identification of fungal lignocellulose-degrading biocatalysts secreted by Phanerochaete chrysosporium via activity-based protein profiling
Activity-based protein profiling is used to screen lignocellulose-degrading enzymes from the white rot fungus Phanerochaete chrysosporium to identify those specifically active in the presence of wood substrate.Activity-based protein profiling (ABPP) has emerged as a versatile biochemical method for studying enzyme activity under various physiological conditions, with applications so far mainly in biomedicine. Here, we show the potential of ABPP in the discovery of biocatalysts from the thermophilic and lignocellulose-degrading white rot fungus Phanerochaete chrysosporium. By employing a comparative ABPP-based functional screen, including a direct profiling of wood substrate-bound enzymes, we identify those lignocellulose-degrading carbohydrate esterase (CE1 and CE15) and glycoside hydrolase (GH3, GH5, GH16, GH17, GH18, GH25, GH30, GH74 and GH79) enzymes specifically active in presence of the substrate. As expression of fungal enzymes remains challenging, our ABPP-mediated approach represents a preselection procedure for focusing experimental efforts on the most promising biocatalysts. Furthermore, this approach may also allow the functional annotation of domains-of-unknown functions (DUFs). The ABPP-based biocatalyst screening described here may thus allow the identification of active enzymes in a process of interest and the elucidation of novel biocatalysts that share no sequence similarity to known counterparts.Bio-organic Synthesi
- âŠ