As part of a worldwide survey of the indoor mycobiota, dust was collected from nine countries. Analyses of dust samples included the culture-dependent dilution-to-extinction method and the ...culture-independent 454-pyrosequencing. Of the 7 904 isolates, 2 717 isolates were identified as belonging to Aspergillus, Penicillium and Talaromyces. The aim of this study was to identify isolates to species level and describe the new species found. Secondly, we wanted to create a reliable reference sequence database to be used for next-generation sequencing projects. Isolates represented 59 Aspergillus species, including eight undescribed species, 49 Penicillium species of which seven were undescribed and 18 Talaromyces species including three described here as new. In total, 568 ITS barcodes were generated, and 391 β-tubulin and 507 calmodulin sequences, which serve as alternative identification markers.
Comparative Genomics of Listeria Species Glaser, P.; Frangeul, L.; Buchrieser, C. ...
Science (American Association for the Advancement of Science),
10/2001, Letnik:
294, Številka:
5543
Journal Article
Recenzirano
Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. ...monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.
The accelerated global movement of plant pathogens has become a substantial threat to rare and endangered plants. Although application of synthetic pesticides on endangered plants is often necessary ...to control disease in greenhouse settings, these chemical treatments degrade the leaf microbiome. This reduction in diversity can eliminate foliar microbes that are essential for pathogen resistance, making plant hosts more susceptible to disease once outplanted in the wild. Beneficial microbes that naturally occur in plant tissue are a resource that is quickly gaining traction as a viable means to increase plant fitness and pathogen resistance in both agricultural and wild habitats. This is of particular interest for threatened and endangered wild plant populations with limited genetic variation where breeding for resistance is not possible. In this experiment, we tested the effectiveness of microbial inoculations to inhibit the fungal pathogen Austropuccinia psidii, which is currently threatening the critically endangered Hawaiian Eugenia koolauensis with extinction. Using molecular and culture-based methods, we characterize foliar fungal communities of Myrtaceous hosts resistant to A. psidii and introduced these diverse fungi into the microbiome of E. koolauensis leaves. Our results indicate that transplanting an intact mycobiome community is more effective at reducing foliar disease resistance when compared with single-fungal-species inocula. These findings demonstrate the potential of whole-microbiome transplants as a powerful tool to inducing disease resistance and enhancing plant health within a conservation context.
Three closely related fungal metabolites, zaragozic acids A, B, and C, that are potent inhibitors of squalene synthase have been isolated and characterized. Zaragozic acids A, B, and C were produced ...from an unidentified sterile fungal culture, Sporormiella intermedia, and Leptodontium elatius, respectively. The structures of the zaragozic acids and their trimethyl esters were determined by a combination of physical and chemical techniques. The zaragozic acids are characterized by a novel 2,8-dioxobicyclo3.2.1octane-4,6,7-trihydroxyl-3,4,5-tricarboxylic acid core and differ from each other in the structures of the 6-acyl and 1-alkyl side chains. They were found to be potent competitive inhibitors of rat liver squalene synthase with apparent Ki values of 78 pM, 29 pM, and 45 pM, respectively. They inhibited cholesterol synthesis in Hep G2 cells, and zaragozic acid A was an inhibitor of acute hepatic cholesterol synthesis in the mouse (50% inhibitory dose of 200 micrograms/kg of body weight). Inhibition of squalene synthase in cells and in vivo was accompanied by an accumulation of label from 3Hmevalonate into farnesyl diphosphate, farnesol, and organic acids. These data indicate that the zaragozic acids are a previously unreported class of therapeutic agents with potential for the treatment of hypercholesterolemia
Samples of relatively acid hydrothermal fluids were collected in the spring of 1996 from seeps, springs, and wells on the Island of Vulcano in the southern Tyrrhenian Sea and analyzed for volatile ...fatty acids
1
The term “volatile fatty acid” is used in the present communication to denote any monocarboxylic acid with ≤5 carbon atoms per molecule.
1
using liquid chromatography. Concentrations of VFAs in the seeps were in the range 65–140
ppb formic, 133–184
ppb acetic, and <100–192
ppb propanoic acids. Spring samples could not be analyzed quantitatively because high salt content effectively “masked” all potential VFA peaks in the corresponding chromatograms, and the concentrations of formic, acetic, and propanoic acids in the wells were <200
ppb. The temperatures of the sampled fluids were between 19.4 and 98.4°C, and the pH measured at
in situ temperatures ranged from 1.85 to 6.17. The concentrations of acetic acid in the seeps were generally higher than both those of formic and propanoic acids. This is consistent with concentrations of VFAs in a saline spring near the Dead Sea reported by Kawamura and Nissenbaum as well as with thermodynamic calculations by Helgeson et al. for equilibrium activities of
n-carboxylic acids in oil-field waters. Although the measured concentrations of VFAs in the hot springs of Vulcano are modest, thermodynamic calculations indicate that they represent potential energy sources for anaerobic chemotrophic microorganisms.
Collaborating Authors: Bee Gunn, Wayne Law, George Yatskievych, Wu Sugong, Fang Zhendong, Ma Jian, Wang Yuhua, Andrew Willson, Peng Shengjing, Zhang Chuanling, Sun Hongyan, Meng Zhengui, Liu Lin, ...Senam Dorji, Ana, Liqing Wangcuo, Sila Cili, Adu, Naji, Amu, Sila Cimu, Sila Lamu, Lurong Pingding, Zhima Yongzong, Loangbao, Bianma Cimu, Gerong Cili, Wang Kai, Sila Pingchu, Axima, and Benjamin Staver. Tibetan land use near Khawa Karpo, Northwest Yunnan, China, incorporates indigenous forest management, gathering, pastoralism, and agriculture. With field-based GIS, repeat photography, and Participatory Rural Appraisal we quantitatively compare land use between higher and lower villages, and between villages with and without roads. Households in higher elevation (>3,000 meters) villages cultivate more farmland (z = −5.387, P ≤ 0.001), a greater diversity of major crops (z = −5.760, P < 0.001), a higher percentage of traditional crops, and fewer cash crops (z = −2.430, P = 0.015) than those in lower elevation villages (<2,500 meters). Villages with roads grow significantly more cash crops (z = −6.794, P ≤ 0.001). Both lower villages and villages with roads travel farther to access common property resources. Historical analyses indicate agricultural intensification in valleys, an increase in houses, new crop introduction, hillside aforestation, cessation of hunting, glacial retreat, and timber-line advance within the past century. We suggest that Tibetan land use reveals trade-offs between high, remote villages and lower villages near roads. Higher villages offer abundant land and access to natural resources but short growing seasons and little market access; in contrast, lower villages have road and market access, an extended growing season, and modern technology, but limited access to land and many other natural resources.
Efficient replication in vivo is essential for a microparasite to colonize its host and the understanding of the molecular mechanisms by which microbial pathogens grow within host tissues can lead to ...the discovery of novel therapies to treat infection. Here we present evidence that the foodborne bacterial pathogen Listeria monocytogenes, a facultative intracellular parasite, exploits hexose phosphates (HP) from the host cell as a source of carbon and energy to fuel fast intracellular growth. HP uptake is mediated by Hpt, a bacterial homolog of the mammalian translocase that transports glucose-6-phosphate from the cytosol into the endoplasmic reticulum in the final step of gluconeogenesis and glycogenolysis. Expression of the Hpt permease is tightly controlled by the central virulence regulator PrfA, which upon entry into host cells induces a set of virulence factors required for listerial intracellular parasitism. Loss of Hpt resulted in impaired listerial intracytosolic proliferation and attenuated virulence in mice. Hpt is the first virulence factor to be identified as specifically involved in the replication phase of a facultative intracellular pathogen. It is also a clear example of how adaptation to intracellular parasitism by microbial pathogens involves mimicry of physiological mechanisms of their eukaryotic host cells.
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