scholarly journals Secondary chemicals protect mould from fungivory

2007 ◽  
Vol 3 (5) ◽  
pp. 523-525 ◽  
Author(s):  
Marko Rohlfs ◽  
Martin Albert ◽  
Nancy P Keller ◽  
Frank Kempken
Keyword(s):  
Secondary Metabolites ◽  
Food Choice ◽  
Fungal Biomass ◽  
Protective Role ◽  
Wild Type ◽  
Global Regulator ◽  
Selective Force ◽  
Choice Behaviour ◽  
Secondary Chemicals ◽  
Fungal Secondary Metabolites

The vast repertoire of toxic fungal secondary metabolites has long been assumed to have an evolved protective role against fungivory. It still remains elusive, however, whether fungi contain these compounds as an anti-predator adaptation. We demonstrate that loss of secondary metabolites in the soil mould Aspergillus nidulans causes, under the attack of the fungivorous springtail Folsomia candida , a disadvantage to the fungus. Springtails exhibited a distinct preference for feeding on a mutant deleted for LaeA, a global regulator of Aspergillus secondary metabolites. Consumption of the mutant yielded a reproductive advantage to the arthropod but detrimental effects on fungal biomass compared with a wild-type fungus capable of producing the entire arsenal of secondary metabolites. Our results demonstrate that fungal secondary metabolites shape food choice behaviour, can affect population dynamics of fungivores, and suggest that fungivores may provide a selective force favouring secondary metabolites synthesis in fungi.

scholarly journals CodY Is a Global Regulator of Virulence-Associated Properties for Clostridium perfringens Type D Strain CN3718

mBio ◽  
2013 ◽  
Vol 4 (5) ◽  
Author(s):  
Jihong Li ◽  
Menglin Ma ◽  
Mahfuzur R. Sarker ◽  
Bruce A. McClane
Keyword(s):  
Clostridium Perfringens ◽  
Null Mutant ◽  
Intestinal Infection ◽  
Wild Type ◽  
Global Regulator ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Type D ◽  
Epsilon Toxin ◽  
Virulence Properties

ABSTRACT CodY is known to regulate various virulence properties in several Gram-positive bacteria but has not yet been studied in the important histotoxic and intestinal pathogen Clostridium perfringens. The present study prepared an isogenic codY-null mutant in C. perfringens type D strain CN3718 by insertional mutagenesis using the Targetron system. Western blot analysis indicated that, relative to wild-type CN3718 or a complementing strain, this isogenic codY mutant produces reduced levels of epsilon toxin (ETX). Using supernatants from cultures of the wild-type, codY-null mutant, and complementing strains, CodY regulation of ETX production was shown to have cytotoxic consequences for MDCK cells. The CodY regulatory effect on ETX production was specific, since the codY-null mutant still made wild-type levels of alpha-toxin and perfringolysin O. Sialidase activity measurements and sialidase Western blot analysis of supernatants from CN3718 and its isogenic derivatives showed that CodY represses overall exosialidase activity due to a reduced presence of NanH in culture supernatants. Inactivation of the codY gene significantly decreased the adherence of CN3718 vegetative cells or spores to host Caco-2 cells. Finally, the codY mutant showed increased spore formation under vegetative growth conditions, although germination of these spores was impaired. Overall, these results identify CodY as a global regulator of many C. perfringens virulence-associated properties. Furthermore, they establish that, via CodY, CN3718 coordinately regulates many virulence-associated properties likely needed for intestinal infection. IMPORTANCE Clostridium perfringens is a major human and livestock pathogen because it produces many potent toxins. C. perfringens type D strains cause intestinal infections by producing toxins, especially epsilon toxin (ETX). Previous studies identified CodY as a regulator of certain virulence properties in other Gram-positive bacteria. Our study now demonstrates that CodY is a global regulator of virulence-associated properties for type D strain CN3718. It promotes production of ETX, attachment of CN3718 vegetative cells or spores to host enterocyte-like Caco-2 cells, and spore germination; the last two effects may assist intestinal colonization. In contrast, CodY represses sporulation. These results provide the first evidence that CodY can function as a global regulator of C. perfringens virulence-associated properties and that this strain coordinately regulates its virulence-associated properties using CodY to increase ETX production, host cell attachment, and spore germination but to repress sporulation, as would be optimal during type D intestinal infection.

Class B Scavenger Receptors BI and BII Protect Against LPS-induced Acute Lung Injury in Mice by Mediating LPS Clearance

2021 ◽  
Author(s):  
Irina N. Baranova ◽  
Alexander V. Bocharov ◽  
Tatyana G. Vishnyakova ◽  
Zhigang Chen ◽  
Anna A. Birukova ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Transgenic Mice ◽  
Neutrophil Infiltration ◽  
Lavage Fluid ◽  
Protective Role ◽  
Lung Damage ◽  
Wild Type ◽  
Class B ◽  
Anti Inflammatory

Recent studies suggest an anti-inflammatory protective role for class B scavenger receptor BI (SR-BI) in endotoxin-induced inflammation and sepsis. Other data, including ours, provide evidence for an alternative role of SR-BI, facilitating bacterial and endotoxin uptake, and contributing to inflammation and bacterial infection. Enhanced endotoxin susceptibility of SR-BI deficient mice due to their anti-inflammatory glucocorticoid deficiency complicates understanding SR-BI’s role in endotoxemia/sepsis, calling for use of alternative models. In this study, using hSR-BI and hSR-BII transgenic mice, we found that SR-BI and to a lesser extent its splicing variant SR-BII, protects against LPS-induced lung damage. At 20 hours after intratracheal LPS instillation the extent of pulmonary inflammation and vascular leakage was significantly lower in hSR-BI and hSR-BII transgenic mice compared to wild type mice. Higher bronchoalveolar lavage fluid (BALF) inflammatory cell count and protein content as well as lung tissue neutrophil infiltration found in wild type mice was associated with markedly (2-3 times) increased pro-inflammatory cytokine production as compared to transgenic mice following LPS administration. Markedly lower endotoxin levels detected in BALF of transgenic vs. wild type mice along with the significantly increased BODIPY-LPS uptake observed in lungs of hSR-BI and hSR-BII mice 20 hours after the IT LPS injection suggest that hSR-BI and hSR-BII-mediated enhanced LPS clearance in the airways could represent the mechanism of their protective role against LPS-induced acute lung injury.

scholarly journals Understanding socio-economic inequalities in food choice behaviour: can Maslow's pyramid help?

2015 ◽  
Vol 113 (7) ◽  
pp. 1139-1147 ◽  
Author(s):  
Frank J. van Lenthe ◽  
Tessa Jansen ◽  
Carlijn B. M. Kamphuis
Keyword(s):  
Food Choice ◽  
Daily Life ◽  
Food Choices ◽  
Healthy Food ◽  
Hierarchy Of Needs ◽  
Choice Behaviour ◽  
Human Needs ◽  
Education Group ◽  
Dairy Consumption ◽  
Economic Inequalities

Socio-economic groups differ in their material, living, working and social circumstances, which may result in different priorities about their daily-life needs, including the priority to make healthy food choices. Following Maslow's hierarchy of human needs, we hypothesised that socio-economic inequalities in healthy food choices can be explained by differences in the levels of need fulfilment. Postal survey data collected in 2011 (67·2 % response) from 2903 participants aged 20–75 years in the Dutch GLOBE (Gezondheid en Levens Omstandigheden Bevolking Eindhoven en omstreken) study were analysed. Maslow's hierarchy of human needs (measured with the Basic Need Satisfaction Inventory) was added to age- and sex-adjusted linear regression models that linked education and net household income levels to healthy food choices (measured by a FFQ). Most participants (38·6 %) were in the self-actualisation layer of the pyramid. This proportion was highest among the highest education group (47·6 %). Being in a higher level of the hierarchy was associated with a higher consumption of fruits and vegetables as well as more healthy than unhealthy bread, snack and dairy consumption. Educational inequalities in fruit and vegetable intake (B= − 1·79, 95 % CI − 2·31, − 1·28 in the lowest education group) were most reduced after the hierarchy of needs score was included (B= − 1·57, 95 % CI − 2·09, − 1·05). Inequalities in other healthy food choices hardly changed after the hierarchy of needs score was included. People who are satisfied with higher-level needs make healthier food choices. Studies aimed at understanding socio-economic inequalities in food choice behaviour need to take differences in the priority given to daily-life needs by different socio-economic groups into account, but Maslow's pyramid offers little help.

Mycotoxins: Fungal Secondary Metabolites with Toxic Properties

Fungi ◽  
2018 ◽  
pp. 318-371
Author(s):  
P.M. Cano ◽  
O. Puel ◽  
I.P. Oswald
Keyword(s):  
Secondary Metabolites ◽  
Fungal Secondary Metabolites

scholarly journals Vibrio gazogenes inhibits aflatoxin production through downregulation of aflatoxin biosynthetic genes in Aspergillus flavus

2022 ◽  
Author(s):  
Shyam L. Kandel ◽  
Rubaiya Jesmin ◽  
Brian M. Mack ◽  
Rajtilak Majumdar ◽  
Matthew K. Gilbert ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Secondary Metabolite ◽  
Aspergillus Flavus ◽  
Fungal Biomass ◽  
Expression Profiles ◽  
Health Hazard ◽  
Gene Clusters ◽  
Aflatoxin Contamination ◽  
Aflatoxin Biosynthesis ◽  
Control Samples

Aspergillus flavus is an opportunistic pathogen of oilseed crops such as maize, peanut, cottonseed, and tree nuts and produces carcinogenic secondary metabolites known as aflatoxins during seed colonization. Aflatoxin contamination not only reduces the value of the produce but also is a health hazard to humans and animals. Previously, we observed inhibition of A. flavus aflatoxin biosynthesis upon exposure to the marine bacterium, Vibrio gazogenes (Vg). In this study, we used RNA sequencing to examine the transcriptional profiles of A. flavus treated with both live and heat-inactivated dead Vg and control samples. Fungal biomass, total accumulated aflatoxins, and expression profiles of genes constituting secondary metabolite biosynthetic gene clusters were determined at 24, 30, and 40 h after treatment. Statistically significant reductions in total aflatoxins were detected in Vg-treated samples as compared to control samples at 40 h. But no statistical difference in fungal biomass was observed upon these treatments. The Vg treatments were most effective on aflatoxin biosynthesis as was reflected in significant downregulation of majority of the genes in the aflatoxin gene cluster including the aflatoxin pathway regulator gene, aflR. Along with aflatoxin genes, we also observed significant downregulation in some other secondary metabolite gene clusters including cyclopiazonic acid and aflavarin, suggesting that the treatment may inhibit other secondary metabolites as well. Finally, a weighted gene correlation network analysis identified an upregulation of ten genes that were most strongly associated with Vg-dependent aflatoxin inhibition and provide a novel start-point in understanding the mechanisms that result in this phenomenon.

scholarly journals Nrf2 Regulates Granuloma Formation and Macrophage Activation during Mycobacterium avium Infection via Mediating Nramp1 and HO-1 Expressions

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Masayuki Nakajima ◽  
Masashi Matsuyama ◽  
Mio Kawaguchi ◽  
Takumi Kiwamoto ◽  
Yosuke Matsuno ◽  
...  
Keyword(s):  
Mycobacterium Avium ◽  
Alveolar Macrophages ◽  
Protective Role ◽  
Granuloma Formation ◽  
Host Susceptibility ◽  
Wild Type ◽  
Critical Determinant ◽  
Content Type ◽  
Avium Infection ◽  
Deficient Mice

ABSTRACT Nrf2 is a redox-sensitive transcription factor that is thought to be important in protection against intracellular pathogens. To determine the protective role of Nrf2 in the host defense against Mycobacterium avium complex (MAC), both wild-type and Nrf2-deficient mice were intranasally infected with MAC bacteria. Nrf2-deficient mice were highly susceptible to MAC bacteria compared with wild-type mice. There were no significant changes in the levels of oxidative stress and Th1 cytokine production between genotypes. Comprehensive transcriptome analysis showed that the expressions of Nramp1 and HO-1 were much lower in the infected lungs, and the expression of Nramp1 was especially lower in alveolar macrophages of Nrf2-deficient mice than of wild-type mice. Electron microscopy showed that many infected alveolar macrophages from Nrf2-deficient mice contained a large number of intracellular MAC bacteria with little formation of phagolysosomes, compared with those from wild-type mice. Treatment with sulforaphane, an activator of Nrf2, increased resistance to MAC with increased lung expression of Nramp1 and HO-1 in wild-type mice. These results indicate that Nramp1 and HO-1, regulated by Nrf2, are essential in defending against MAC infection due to the promotion of phagolysosome fusion and granuloma formation, respectively. Thus, Nrf2 is thought to be a critical determinant of host resistance to MAC infection. IMPORTANCE Nontuberculous mycobacteria (NTM) are an important cause of morbidity and mortality in pulmonary infections. Among them, Mycobacterium avium complex (MAC) is the most common cause of pulmonary NTM disease worldwide. It is thought that both environmental exposure and host susceptibility are required for the establishment of pulmonary MAC disease, because pulmonary MAC diseases are most commonly observed in slender, postmenopausal women without a clearly recognized immunodeficiency. However, host factors that regulate MAC susceptibility have not been elucidated until now. This study shows that Nrf2 is a critical regulator of host susceptibility to pulmonary MAC disease by promoting phagolysosome fusion and granuloma formation via activating Nramp1 and HO-1 genes, respectively. The Nrf2 system is activated in alveolar macrophages, the most important cells during MAC infection, as both the main reservoir of infection and bacillus-killing cells. Thus, augmentation of Nrf2 might be a useful therapeutic approach for protection against pulmonary MAC disease.

scholarly journals Secondary metabolites of a marine-derived Penicillium ochrochloron

2021 ◽  
Vol 13 (3) ◽  
pp. 11020
Author(s):  
Peter M. EZE ◽  
Ying GAO ◽  
Yang LIU ◽  
Lasse Van GEELEN ◽  
Chika P. EJIKEUGWU ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Secondary Metabolites ◽  
Biological Properties ◽  
Industrial Applications ◽  
Biologically Active ◽  
Fungal Isolation ◽  
The North ◽  
Wide Range ◽  
Extremophilic Fungi ◽  
Fungal Secondary Metabolites

Extremophilic fungi have received considerable attention recently as new promising sources of biologically active compounds with potential pharmaceutical applications. This study investigated the secondary metabolites of a marine-derived Penicillium ochrochloron isolated from underwater sea sand collected from the North Sea in St. Peter-Ording, Germany. Standard techniques were used for fungal isolation, taxonomic identification, fermentation, extraction, and isolation of fungal secondary metabolites. Chromatographic separation and spectroscopic analyses of the fungal secondary metabolites yielded eight compounds: talumarin A (1), aspergillumarin A (2), andrastin A (3), clavatol (4), 3-acetylphenol (5), methyl 2,5-dihydro-4-hydroxy-5-oxo-3-phenyl-2-furanpropanoate (6), emodin (7) and 2-chloroemodin (8). After co-cultivation with Bacillus subtilis, the fungus was induced to express (-)-striatisporolide A (9). Compound 1 was evaluated for antibacterial activity against Staphylococcus aureus, Acinetobacter baumannii, Mycobacterium smegmatis, and M. tuberculosis, as well as cytotoxicity against THP-1 cells. The compound, however, was not cytotoxic to THP-1 cells and had no antibacterial activity against the microorganisms tested. The compounds isolated from P. ochrochloron in this study are well-known compounds with a wide range of beneficial biological properties that can be explored for pharmaceutical, agricultural, or industrial applications. This study highlights the bioprospecting potential of marine fungi and confirms co-cultivation as a useful strategy for the discovery of new natural products.

scholarly journals Paraoxonase-1 Inhibits Oxidized Low-Density Lipoprotein-Induced Metabolic Alterations and Apoptosis in Endothelial Cells: A Nondirected Metabolomic Study

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Anabel García-Heredia ◽  
Judit Marsillach ◽  
Anna Rull ◽  
Iris Triguero ◽  
Isabel Fort ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Current Knowledge ◽  
Oxidized Ldl ◽  
Density Lipoprotein ◽  
Wild Type Mouse ◽  
Protective Role ◽  
Paraoxonase 1 ◽  
Wild Type ◽  
Metabolic Alterations ◽  
Deficient Mice

We studied the influence of PON1 on metabolic alterations induced by oxidized LDL when incubated with endothelial cells. HUVEC cells were incubated with native LDL, oxidized LDL, oxidized LDL plus HDL from wild type mice, and oxidized LDL plus HDL from PON1-deficient mice. Results showed alterations in carbohydrate and phospholipid metabolism and increased apoptosis in cells incubated with oxidized LDL. These changes were partially prevented by wild type mouse HDL, but the effects were less effective with HDL from PON1-deficient mice. Our results suggest that PON1 may play a significant role in endothelial cell survival by protecting cells from alterations in the respiratory chain induced by oxidized LDL. These results extend current knowledge on the protective role of HDL and PON1 against oxidation and apoptosis in endothelial cells.

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