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1.
Pepijn W Kooij Adelina Rogowska-Wrzesinska Daniel Hoffmann Peter Roepstorff Jacobus J Boomsma Morten Schi?tt 《The ISME journal》2014,8(5):1032-1040
The mutualism between leaf-cutting ants and their fungal symbionts revolves around processing and inoculation of fresh leaf pulp in underground fungus gardens, mediated by ant fecal fluid deposited on the newly added plant substrate. As herbivorous feeding often implies that growth is nitrogen limited, we cloned and sequenced six fungal proteases found in the fecal fluid of the leaf-cutting ant Acromyrmex echinatior and identified them as two metalloendoproteases, two serine proteases and two aspartic proteases. The metalloendoproteases and serine proteases showed significant activity in fecal fluid at pH values of 5–7, but the aspartic proteases were inactive across a pH range of 3–10. Protease activity disappeared when the ants were kept on a sugar water diet without fungus. Relative to normal mycelium, both metalloendoproteases, both serine proteases and one aspartic protease were upregulated in the gongylidia, specialized hyphal tips whose only known function is to provide food to the ants. These combined results indicate that the enzymes are derived from the ingested fungal tissues. We infer that the five proteases are likely to accelerate protein extraction from plant cells in the leaf pulp that the ants add to the fungus garden, but regulatory functions such as activation of proenzymes are also possible, particularly for the aspartic proteases that were present but without showing activity. The proteases had high sequence similarities to proteolytic enzymes of phytopathogenic fungi, consistent with previous indications of convergent evolution of decomposition enzymes in attine ant fungal symbionts and phytopathogenic fungi. 相似文献
2.
Frank O. Aylward Lily Khadempour Daniel M. Tremmel Bradon R. McDonald Carrie D. Nicora Si Wu Ronald J. Moore Daniel J. Orton Matthew E. Monroe Paul D. Piehowski Samuel O. Purvine Richard D. Smith Mary S. Lipton Kristin E. Burnum-Johnson Cameron R. Currie 《PloS one》2015,10(8)
Leaf-cutter ants are prolific and conspicuous constituents of Neotropical ecosystems that derive energy from specialized fungus gardens they cultivate using prodigious amounts of foliar biomass. The basidiomycetous cultivar of the ants, Leucoagaricus gongylophorus, produces specialized hyphal swellings called gongylidia that serve as the primary food source of ant colonies. Gongylidia also contain plant biomass-degrading enzymes that become concentrated in ant digestive tracts and are deposited within fecal droplets onto fresh foliar material as ants incorporate it into the fungus garden. Although the enzymes concentrated by L. gongylophorus within gongylidia are thought to be critical to the initial degradation of plant biomass, only a few enzymes present in these hyphal swellings have been identified. Here we use proteomic methods to identify proteins present in the gongylidia of three Atta cephalotes colonies. Our results demonstrate that a diverse but consistent set of enzymes is present in gongylidia, including numerous plant biomass-degrading enzymes likely involved in the degradation of polysaccharides, plant toxins, and proteins. Overall, gongylidia contained over three quarters of all biomass-degrading enzymes identified in the L. gongylophorus genome, demonstrating that the majority of the enzymes produced by this fungus for biomass breakdown are ingested by the ants. We also identify a set of 40 of these enzymes enriched in gongylidia compared to whole fungus garden samples, suggesting that certain enzymes may be particularly important in the initial degradation of foliar material. Our work sheds light on the complex interplay between leaf-cutter ants and their fungal symbiont that allows for the host insects to occupy an herbivorous niche by indirectly deriving energy from plant biomass. 相似文献
3.
Virginia E. Masiulionis Christian Rabeling Henrik H. De Fine Licht Ted Schultz Maurício Bacci Jr Cintia M. Santos. Bezerra Fernando C. Pagnocca 《PloS one》2014,9(8)
Attine ants cultivate fungi as their most important food source and in turn the fungus is nourished, protected against harmful microorganisms, and dispersed by the ants. This symbiosis evolved approximately 50–60 million years ago in the late Paleocene or early Eocene, and since its origin attine ants have acquired a variety of fungal mutualists in the Leucocoprineae and the distantly related Pterulaceae. The most specialized symbiotic interaction is referred to as “higher agriculture” and includes leafcutter ant agriculture in which the ants cultivate the single species Leucoagaricus gongylophorus. Higher agriculture fungal cultivars are characterized by specialized hyphal tip swellings, so-called gongylidia, which are considered a unique, derived morphological adaptation of higher attine fungi thought to be absent in lower attine fungi. Rare reports of gongylidia-like structures in fungus gardens of lower attines exist, but it was never tested whether these represent rare switches of lower attines to L. gonglyphorus cultivars or whether lower attine cultivars occasionally produce gongylidia. Here we describe the occurrence of gongylidia-like structures in fungus gardens of the asexual lower attine ant Mycocepurus smithii. To test whether M. smithii cultivates leafcutter ant fungi or whether lower attine cultivars produce gongylidia, we identified the M. smithii fungus utilizing molecular and morphological methods. Results shows that the gongylidia-like structures of M. smithii gardens are morphologically similar to gongylidia of higher attine fungus gardens and can only be distinguished by their slightly smaller size. A molecular phylogenetic analysis of the fungal ITS sequence indicates that the gongylidia-bearing M. smithii cultivar belongs to the so-called “Clade 1”of lower Attini cultivars. Given that M. smithii is capable of cultivating a morphologically and genetically diverse array of fungal symbionts, we discuss whether asexuality of the ant host maybe correlated with low partner fidelity and active symbiont choice between fungus and ant mutualists. 相似文献
4.
Background and Aims
The structures of arbuscular mycorrhizal (AM) fungi (hyphae, arbuscules, vesicles, spores) are used to make inferences about fungal activity based on stored samples, yet the impact of storage method has not been quantified, despite known effects of temperature and host condition on AM fungal colonisation.Methods
We measured how four storage treatments (cool or ambient conditions, with and without plant shoots attached, i.e. n?=?four treatment combinations) affected AM fungal colonisation of subterranean clover (Trifolium subterraneum L.) after 0, 2, 6 and 10 days of storage. Roots were assessed for colonisation of fine root endophyte and coarse AM fungi.Results
For coarse AM fungi, total colonisation was unaffected, but arbuscules were reduced at Day 6 and increased again by Day 10, except Ambient-Minus-Shoots. There was a loss of vesicles in all treatments at Day 2, and an increase in spore number at Day 6 within Cool-Plus-Shoots. In contrast, for fine root endophyte, total colonisation was greatly reduced at Day 6 but increased again at Day 10, in all except the Cool-Plus-Shoots treatment.Conclusions
Our data demonstrate that AM fungal activity is not suspended in commonly used plant storage conditions. Storage method and time impacted AM fungal colonisation, particularly for fine root endophyte. We recommend samples are processed within 2 days of harvest.5.
Objective
To protect the enzymes during fed-batch cellulase production by means of partial enzyme recovery at regular intervals.Results
Extracellular enzymes were partially recovered at the intervals of 1, 2, or 3 days. Mycelia were also removed to avoid contamination. Increases in the total harvested cellulase (24–62%) and β-glucosidase (22–76%) were achieved. In fermentor cultivation when the enzymes were recovered every day with 15% culture broth. The total harvested cellulase and β-glucosidase activity increased by 43 and 58%, respectively, with fungal cell concentration maintained at 3.5–4.5 g l?1.Conclusion
Enzyme recovery at regular intervals during fed-batch cellulase cultivation could protect the enzyme in the culture broth and enhance the enzyme production when the fungal cell concentration is maintained in a reasonable range.6.
Purpose of Review
To address the latest treatments used for pityriasis versicolor and identify those that have proven to be effective in recent publications.Recent Findings
Even though Malassezia spp. have shown resistance to antifungals, classical treatments continue to be effective, and other novelty therapies including light therapies have shown promising results in the treatment of this condition.Summary
Pityriasis versicolor is a common superficial fungal infection of the skin. There are numerous and diverse topical and systemic therapeutic options that are successful for the treatment and prophylaxis of this mycosis. New substances that act against the fungus through other mechanisms of action different from those used until now are expected in the near future.7.
Background and aims
Variations in root-associated fungal communities contribute to the so-called ‘crop rotation benefit’ on soil productivity. We assessed the effects of chickpea, lentil, and pea in wheat-based rotations, as compared to wheat monoculture, on the structure of root-associated fungal communities, and described the legacy of pulses on a following wheat crop.Methods
The internal transcribed spacer (ITS) and 18S rRNA gene markers, and 454 amplicon pyrosequencing were used to describe the fungal communities of crop roots and rhizosphere soil in a field experiment and agronomic data were collected.Results
Pulses influenced only the structure of the non-mycorrhizal fungal community of roots. Fusarium tricinctum, Clonostachys rosea, Fusarium redolens, and Cryptococcus sp. were specific to certain crops. Despite the absence of selective effects of pulses on their associated arbuscular mycorrhizal (AM) fungal community, pea had a legacy effect on the structure of the AM fungal community associated with the roots of the following wheat crop, in one of the two year/sites examined. Species of Mortierella, Cryptococcus, and Paraglomus in wheat rhizosphere soil may benefit yield, whereas species of Fusarium, Davidiella, Lachnum, Sistotrema and Podospora may reduce yield.Conclusion
The effect of pulse crops on root fungal communities varied with rotation crop species. Pulses had various effects on the physiology of the following wheat crop, including increased productivity.8.
Joshua S. Hardin Deanna A. Sutton Nathan P. Wiederhold James Mele Sunali Goyal 《Mycopathologia》2017,182(7-8):755-759
Purpose
We report the first case of human infection and keratitis secondary to Trametes betulina, a rare filamentous fungus.Methods
Clinical examination including external and slit-lamp examination and corneal scrapings with microbiologic evaluation were performed on a patient with chronic allergic conjunctivitis, entropion and a long-standing corneal ulcer resistant to treatment.Results
The culture from the corneal scraping revealed a basidiomycetous fungus which was submitted for identification. DNA extraction with sequencing and analysis of the ITS and D1/D2 regions were performed on the isolate and demonstrated 100% similarity to Lenzites betulina/Trametes betulina. Susceptibility testing demonstrated potent in vitro activity of voriconazole (MIC < 0.03 μg/ml). The patient was treated with voriconazole, and the corneal ulcer and infiltrate resolved. The infection resulted in corneal thinning and a dense central corneal scar. Penetrating keratoplasty was performed 5 months after diagnosis and treatment and revealed stromal scarring without fungal elements.Conclusion
This is the first reported case of keratitis caused by Trametes betulina. This organism should be considered in the differential diagnosis for rare filamentous fungal keratitis and its treatment with voriconazole also noted.9.
Maribel Dolande Nataly García Ana María Capote María Mercedes Panizo Giuseppe Ferrara Víctor Alarcón 《Current fungal infection reports》2017,11(4):197-202
Purpose of Review
The purpose of this review is to contribute to the knowledge about the existence of Candida auris as an emerging pathogenic fungus, multi-resistant to antifungal, and causing health care-associated infections (HCAI).Recent Findings
C. auris emerges as yeast with clonal transmission resistance to three families of commonly used antifungals, mainly azoles (fluconazole and voriconazole), diminishing therapeutic options for the treatment of fungal infections. In 2009, C. auris was isolated for the first time in Japan and by the time of this review, it has been reported in different countries in Africa, America, Asia, and Europe.Summary
It is important to identify yeasts of the Candida genus up to species, to perform susceptibility tests and to implement surveillance, prevention, and control measures, to minimize the global spread of this fungus, due to its impact on public health.10.
Tie-juan Shao Zhi-xing He Zhi-jun Xie Hai-chang Li Mei-jiao Wang Cheng-ping Wen 《Metabolomics : Official journal of the Metabolomic Society》2016,12(4):70
Introduction
The differences in fecal metabolome between ankylosing spondylitis (AS)/rheumatoid arthritis (RA) patients and healthy individuals could be the reason for an autoimmune disorder.Objectives
The study explored the fecal metabolome difference between AS/RA patients and healthy controls to clarify human immune disturbance.Methods
Fecal samples from 109 individuals (healthy controls 34, AS 40, and RA 35) were analyzed by 1H NMR spectroscopy. Data were analyzed with principal component analysis (PCA) and orthogonal projection to latent structure discriminant (OPLS-DA) analysis.Results
Significant differences in the fecal metabolic profiles could distinguish AS/RA patients from healthy controls but could not distinguish between AS and RA patients. The significantly decreased metabolites in AS/RA patients were butyrate, propionate, methionine, and hypoxanthine. Significantly increased metabolites in AS/RA patients were taurine, methanol, fumarate, and tryptophan.Conclusion
The metabolome variations in feces indicated AS and RA were two homologous diseases that could not be distinguished by 1H NMR metabolomics.11.
K. Kellner H. Fernández‐Marín H. D. Ishak R. Sen T. A. Linksvayer U. G. Mueller 《Journal of evolutionary biology》2013,26(6):1353-1362
Partner fidelity through vertical symbiont transmission is thought to be the primary mechanism stabilizing cooperation in the mutualism between fungus‐farming (attine) ants and their cultivated fungal symbionts. An alternate or additional mechanism could be adaptive partner or symbiont choice mediating horizontal cultivar transmission or de novo domestication of free‐living fungi. Using microsatellite genotyping for the attine ant Mycocepurus smithii and ITS rDNA sequencing for fungal cultivars, we provide the first detailed population genetic analysis of local ant–fungus associations to test for the relative importance of vertical vs. horizontal transmission in a single attine species. M. smithii is the only known asexual attine ant, and it is furthermore exceptional because it cultivates a far greater cultivar diversity than any other attine ant. Cultivar switching could permit the ants to re‐acquire cultivars after garden loss, to purge inferior cultivars that are locally mal‐adapted or that accumulated deleterious mutations under long‐term asexuality. Compared to other attine ants, symbiont choice and local adaptation of ant–fungus combinations may play a more important role than partner‐fidelity feedback in the co‐evolutionary process of M. smithii and its fungal symbionts. 相似文献
12.
N. Cesbron A.-L. Royer Y. Guitton A. Sydor B. Le Bizec G. Dervilly-Pinel 《Metabolomics : Official journal of the Metabolomic Society》2017,13(8):99
Introduction
Collecting feces is easy. It offers direct outcome to endogenous and microbial metabolites.Objectives
In a context of lack of consensus about fecal sample preparation, especially in animal species, we developed a robust protocol allowing untargeted LC-HRMS fingerprinting.Methods
The conditions of extraction (quantity, preparation, solvents, dilutions) were investigated in bovine feces.Results
A rapid and simple protocol involving feces extraction with methanol (1/3, M/V) followed by centrifugation and a step filtration (10 kDa) was developed.Conclusion
The workflow generated repeatable and informative fingerprints for robust metabolome characterization.13.
14.
15.
Aim and Objectives
Mycotic keratitis, with its diverse clinical presentation and difficulties in treatment, makes it a challenging task for clinicians and an important object of study. The aim of present study was to determine the frequency of occurrence and epidemiological association with identification of fungal isolates from mycotic keratitis cases.Materials and Methods
This was a prospective and observational study conducted in Mycology Laboratory, Department of Microbiology, S.P. Medical College, Bikaner, on corneal scrapings and swabs of a total of 480 patients attending the Ophthalmology OPD, P.B.M. Hospital, Bikaner, during July 2005 to June 2012.Results
Out of 480 suspected cases, 180 were found to be positive for fungus by smear/culture examination. Increased incidence was seen in the months of May to September with Aspergillus fumigatus being the most common isolate.Conclusion
Mycotic keratitis, though an age-old disease, still presented with challenging aspects of diagnosis and treatment. The study showed fungal keratitis is prevalent in rural parts of north-west Rajasthan, mainly found in males (age group 21–40 years) with low socio-economic status (farm or factory workers). The most common cause of fungal keratitis was found to be species of Aspergillus.16.
Tao Chen Zhibiao Nan Xingxu Zhang Fujiang Hou Michael Christensen Carol Baskin 《Plant and Soil》2018,422(1-2):155-168
Aims
Soil fungal pathogens can result in the failure of seedling establishment, but the effects of fungicide applications on seed/seedling survival have differed among studies. We assumed that the variation may relate to seed dormancy/germination characteristics and hypothesized that nondormant germinating seeds are more likely to be killed by fungal pathogens than dormant seeds.Methods
Dormant and nondormant seeds of Stipa bungeana and Lespedeza davurica were inoculated with a pathogenic fungus Fusarium tricinctum under laboratory and field conditions. The outcomes of seed/seedling fate and other parameters were evaluated.Results
In the laboratory, nondormant seeds inoculated with F. tricinctum developed white tufts of mycelium on the radicles of germinating seeds causing them to quickly die, but dormant seeds remained intact. In contrast, in the field inoculation with F. tricinctum did not cause higher mortality of nondormant than dormant seeds but resulted in higher percentages of seedling death before they emerged from soil than the controls.Conclusions
Our results suggest that dormancy protects seeds from being attacked by some pathogens by preventing germination, but the protection is lost once germination has commenced. Further study involving various plant species with more seeds is needed to assess the generality of this pathogen-seed interaction hypothesis.17.
Amélie Dukunde Dominik Schneider Mingji Lu Silja Brady Rolf Daniel 《Biotechnology letters》2017,39(4):577-587
Objectives
To investigate the properties of a novel metagenome-derived member of the hormone-sensitive lipase family of lipolytic enzymes.Results
A forest soil metagenome-derived gene encoding an esterase (Est06) belonging to the hormone-sensitive lipase family of lipolytic enzymes was subcloned, heterologously expressed and characterized. Est06 is a polypeptide of 295 amino acids with a molecular mass of 31 kDa. The deduced protein sequence shares 61% similarity with a hypothetical protein from the marine symbiont Candidatus Entotheonella sp. TSY1. Purified Est06 exhibited high affinity for acyl esters with short-chain fatty acids, and showed optimum activity with p-nitrophenyl valerate (C5). Maximum enzymatic activity was at 50 °C and pH 7. Est06 exhibited high stability at moderate temperatures by retaining all of its catalytic activity below 30 °C over 13 days. Additionally, Est06 displayed high stability between pH 5 and 9. Esterase activity was not inhibited by metal ions or detergents, although organic solvents decreased activity.Conclusions
The combination of Est06 properties place it among novel biocatalysts that have potential for industrial use including low temperature applications.18.
P. A. García-Parisi F. A. Lattanzi A. A. Grimoldi M. Druille M. Omacini 《Plant and Soil》2017,412(1-2):151-162
Aims
Plants interact by modifying soil conditions in plant-soil feedback processes. Foliar endophytes of grasses exert multiple effects on host rhizosphere with potential consequences on plant-soil feedback. Here, we hypothesize that the grass-endophyte symbiosis impairs soil symbiotic potential, and in turn influences legume performance and nitrogen acquisition.Methods
Soil was conditioned in pots, growing Lolium multiflorum with or without the fungal endophyte Epichloë and with or without arbuscular mycorrhizal fungi (AMF). Then, Trifolium repens grew in all types of conditioned soils with high or low rhizobia availability.Results
Endophyte soil conditioning reduced AMF spores number and rhizobial nodules (?27 % and ?38 %, respectively). Seedling survival was lower in endophyte-conditioned soil and higher in mycorrhizal soils (?27 % and +24 %, respectively). High rhizobia-availability allowed greater growth and nitrogen acquisition, independent of soil conditioning. Low rhizobia-availability allowed both effects only in endophyte-conditioned soil.Conclusion
Endophyte-induced changes in soil (i) hindered symbiotic potential by reducing AMF spore availability or rhizobia nodulation, (ii) impaired legume survival irrespective of belowground symbionts presence, but (iii) mimicked rhizobia effects, enhancing growth and nitrogen fixation in poorly nodulated plants. Our results show that shoot and root symbionts can be interactively involved in interspecific plant-soil feedback.19.
Objective
To examine the activities of residual enzymes in dried shiitake mushrooms, which are a traditional foodstuff in Japanese cuisine, for possible applications in food processing.Results
Polysaccharide-degrading enzymes remained intact in dried shiitake mushrooms and the activities of amylase, β-glucosidase and pectinase were high. A potato digestion was tested using dried shiitake powder. The enzymes reacted with potato tuber specimens to solubilize sugars even under a heterogeneous solid-state condition and that their reaction modes were different at 38 and 50 °C.Conclusion
Dried shiitake mushrooms have a potential use in food processing as an enzyme preparation.20.
Christopher W. Armstrong Neil R. McGregor Donald P. Lewis Henry L. Butt Paul R. Gooley 《Metabolomics : Official journal of the Metabolomic Society》2017,13(1):8