Xanthoepocin, a photolabile antibiotic of Penicillium ochrochloron CBS 123823 with high activity against multiresistant gram-positive bacteria.

Background: With the steady increase of antibiotic resistance, several strategies have been proposed in the scientific community to overcome the crisis. One of many successful strategies is the re-evaluation of known compounds, which have been early discarded out of the pipeline, with state-of-the-art know-how. Xanthoepocin, a polyketide widespread among the genus Penicillium with an interesting bioactivity spectrum against gram-positive bacteria, is such a discarded antibiotic.

Challenging the charge balance hypothesis: reconsidering buffer effect and reuptake of previously excreted organic acids by Penicillium ochrochloron.

Penicillium ochrochloron was used in the past for the leaching of zinc from a zinc oxide containing filter dust via excreted organic acids. Organic acid excretion by P. ochrochloron was stimulated by the addition of an extracellular buffer (2-(N-Morpholino)ethanesulfonic acid, MES; or zinc oxide, ZnO: ZnO + 2 H+ → Zn2+ + H2O).

Fungal Growth in Batch Culture - What We Could Benefit If We Start Looking Closer.

Since filamentous fungi rapidly adjust their metabolic properties to environmental changes, a rigorous standardization and characterization of cultivation conditions is necessary to obtain meaningful and reproducible results. In batch cultures, which are commonly characterized according to the classical growth curve in textbooks (i.e.

Critical evaluation of a putative glucosamine excretion by Aspergillus niger CBS120.49 and Penicillium ochrochloron CBS123.824 under citric acid producing conditions.

As one of the most frequently occurring monomers in the biosphere, glucosamine is a valuable metabolite for several applications. Although microbial glucosamine production is still in its infancy, it offers the possibility to circumvent problems associated with traditional production by hydrolysis. Of particular interest is a study with Aspergillus niger, which reports for the first time high glucosamine excretion in the early phase of citric acid production.

The Dynamics of Plasma Membrane, Metabolism and Respiration (PM-M-R) in CBS 123824 in Response to Different Nutrient Limitations-A Multi-level Approach to Study Organic Acid Excretion in Filamentous Fungi.

Filamentous fungi are important cell factories. In contrast, we do not understand well even basic physiological behavior in these organisms. This includes the widespread phenomenon of organic acid excretion.

Rapid sample processing for intracellular metabolite studies in Penicillium ochrochloron CBS 123.824: the FiltRes-device combines cold filtration of methanol quenched biomass with resuspension in extraction solution.

Background: Many issues concerning sample processing for intracellular metabolite studies in filamentous fungi still need to be solved, e.g. how to reduce the contact time of the biomass to the quenching solution in order to minimize metabolite leakage.

Adapting High-Resolution Respirometry to Glucose-Limited Steady State Mycelium of the Filamentous Fungus Penicillium ochrochloron: Method Development and Standardisation.

Fungal electron transport systems (ETS) are branched, involving alternative NADH dehydrogenases and an alternative terminal oxidase. These alternative respiratory enzymes were reported to play a role in pathogenesis, production of antibiotics and excretion of organic acids. The activity of these alternative respiratory enzymes strongly depends on environmental conditions.

Organic Acid Excretion in Penicillium ochrochloron Increases with Ambient pH.

Despite being of high biotechnological relevance, many aspects of organic acid excretion in filamentous fungi like the influence of ambient pH are still insufficiently understood. While the excretion of an individual organic acid may peak at a certain pH value, the few available studies investigating a broader range of organic acids indicate that total organic acid excretion rises with increasing external pH. We hypothesized that this phenomenon might be a general response of filamentous fungi to increased ambient pH.

Transient excretion of succinate from Trichoderma atroviride submerged mycelia reveals the complex movements and metabolism of carboxylates.

Submerged growth of Trichoderma atroviride CCM F 534 on glucose-containing medium was accompanied by the excretion of organic acids (succinate, citrate, alpha-ketoglutarate, fumarate, aconitate). The excretion of succinate was transient. After 48-72 h cultivation, millimolar amounts of succinate disappeared from the medium.

Formation of exudate droplets by Metarhizium anisopliae and the presence of destruxins.

Nutritional conditions causing droplet exudation by Metarhizium anisopliae var. anisopliae were studied. Exudation in droplets occurred only on media with more than one carbon source and was highly dependent on the ratio of a well metabolized sugar such as trehalose and a nonpreferred sugar, in particular arabinose.

Dynamics of energy charge and adenine nucleotides during uncoupling of catabolism and anabolism in Penicillium ochrochloron.

Filamentous fungi are able to spill energy when exposed to energy excess by uncoupling catabolism from anabolism, e.g. via overflow metabolism.

Destruxin production of Metarhizium anisopliae under carbon and nitrogen exhaustion.

Destruxins (dtx) A, B, and E, showing a variety of biological activities, are the main toxic secondary metabolites of the entomopathogenous ascomycete Metarhizium anisopliae Bipesco 5, a widely used biocontrol production strain. Dynamics of dtx biosynthesis were monitored during liquid fermentation in a chemically defined medium. During shake flask cultivation with excess carbon, nitrogen and phosphate, approximately 50, 20, and 100 mg l(-1) dtx A, B, and E were produced after 12 d.

Characteristics of glucose uptake by glucose- and NH4-limited grown Penicillium ochrochloron at low, medium and high glucose concentration.

Glucose uptake by Penicillium ochrochloron (formerly Penicillium simplicissimum) was studied from 0.01 to 400 mM glucose using chemostat culture and bioreactor batch culture. The characteristics of glucose uptake varied considerably with the conditions of growth, harvest and uptake assay.

Algorithm-based design of synthetic growth media stimulating virulence properties of Metarhizium anisopliae conidia.

Aims: Synthetic media should be designed for the production of Metarhizium anisopliae conidia with improved virulence properties.

Methods And Results: A genetic algorithm (GA), demonstrated to be suitable for the design of media for spore mass production (Hutwimmer et al. 2008), was utilized for a multi-objective medium design to improve conidia yield and three proposed virulence properties of conidia: C : N ratio, germination speed and amount of spore-bound Pr1 protease.

Algorithm-based design of novel synthetic media for Metarhizium anisopliae simulating its nutritional conditions in the environment.

Aims: The objective of this study was to develop a novel synthetic growth medium for increased conidium production of the entompathogenic fungus Metarhizium anisopliae. The medium should simulate natural nutritional conditions.

Methods And Results: Macro- and micronutrients were selected in concentrations found in insects or from sources which are believed to be advantageous for virulence.

Interaction of 5-hydroxytryptamine (serotonin) against Aspergillus spp. in vitro.

This study examined the direct interaction of serotonin (5-hydroxytryptamine (5-HT)) with Aspergillus species. Accumulation of 5-HT in aspergilli was investigated by immunofluorescence staining and laser confocal scanning microscopy. The influence of 5-HT on fungal ergosterol content, cell membrane integrity, fungal growth and hyphal elongation was determined.

Determination of adenine and pyridine nucleotides in glucose-limited chemostat cultures of Penicillium simplicissimum by one-step ethanol extraction and ion-pairing liquid chromatography.

Under specific conditions Penicillium simplicissimum excretes large amounts of organic acids, mainly citrate. As the energetic status of the hyphae might play a role in that respect, we developed a method for the determination of adenine (adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate) and pyridine (nicotinamide adenine dinucleotide and reduced nicotinamide adenine dinucleotide (NADH)) nucleotides in hyphae of P. simplicissimum.

Thermodynamic boundary conditions suggest that a passive transport step suffices for citrate excretion in Aspergillus and Penicillium.

Excretion of organic acids, e.g. citrate, by anamorphic fungi is a frequent phenomenon in natural habitats and in laboratory cultures.

Changes in properties of glutamate transport in Trichoderma viride vegetative mycelia upon adaptation to glutamate as carbon source.

The U-(14)C-labelled glutamate uptake was measured in both sucrose- and glutamate-grown mycelia of Trichoderma viride. The biomass yield was five-fold lower with glutamate as a sole carbon source. The rate of glutamate transport measured at a glutamate concentration of 1 mM remained unchanged in glutamate-grown mycelia whereas the properties of the glutamate transport were substantially changed compared to sucrose-grown mycelia.

A faster method for 3D/2D medical image registration--a simulation study.

3D/2D patient-to-computed-tomography (CT) registration is a method to determine a transformation that maps two coordinate systems by comparing a projection image rendered from CT to a real projection image. Iterative variation of the CT's position between rendering steps finally leads to exact registration. Applications include exact patient positioning in radiation therapy, calibration of surgical robots, and pose estimation in computer-aided surgery.

Characterization of the Penicillium chrysogenum antifungal protein PAF.

The filamentous fungus Penicillium chrysogenum abundantly secretes the small, highly basic and cysteine-rich protein PAF ( Penicillium antifungal protein). In this study, the antifungal activity of PAF is described. PAF inhibited the growth of a variety of filamentous fungi, including opportunistic human pathogenic and phytopathogenic fungi, whereas bacterial and yeast cells were unaffected.

Characterization of an inducible citrate uptake system in Penicillium simplicissimum.

When citrate was used as a sole source of carbon, citrate uptake by Penicillium simplicissimum increased 267-fold (if glucose-grown mycelium was adapted to citrate) or 1400-fold (if the fungus was grown on citrate) compared to glucose-grown mycelium. Inhibition of macromolecular synthesis prevented this stimulation of citrate uptake. Citrate uptake by glucose-grown mycelium was low (0.

Succinate synthesis and excretion by Penicillium simplicissimum under aerobic and anaerobic conditions.

Succinate is an interesting chemical for industries producing food and pharmaceutical products, surfactants, detergents and biodegradable plastics. Succinate is produced mainly by a mixed-acid fermentation process using anaerobically growing bacteria. However, succinate excretion is also widespread among fungi.

Efflux of organic acids in Penicillium simplicissimum is an energy-spilling process, adjusting the catabolic carbon flow to the nutrient supply and the activity of catabolic pathways.

Continuous cultivation was used to study the effect of glucose, ammonium, nitrate or phosphate limitation on the excretion of tricarboxylic acid (TCA) cycle intermediates by Penicillium simplicissimum. Additionally, the effect of benzoic acid, salicylhydroxamic acid (SHAM) and 2,4-dinitrophenol on TCA cycle intermediates was studied. The physiological state of the fungus was characterized by its glucose and O(2) consumption, its CO(2) production, its intra- and extracellular concentrations of TCA cycle intermediates, as well as by its biomass yield, its maintenance coefficient and its respiratory quotient.