Genome-scale investigation of phenotypically distinct but nearly clonal Trichoderma strains.

Biological control agents (BCA) are beneficial organisms that are applied to protect plants from pests. Many fungi of the genus Trichoderma are successful BCAs but the underlying mechanisms are not yet fully understood. Trichoderma cf.

Influence of inoculum and anode surface properties on the selection of Geobacter-dominated biofilms.

This study evaluated the impact of inoculum source and anode surface modification (carboxylate -COO(-) and sulfonamide -SO2NH2 groups) on the microbial composition of anode-respiring biofilms. These two factors have not previously been considered in detail. Three different inoculum sources were investigated, a dry aerobic soil, brackish estuarine mud and freshwater sediment.

Maintenance of Geobacter-dominated biofilms in microbial fuel cells treating synthetic wastewater.

Geobacter-dominated biofilms can be selected under stringent conditions that limit the growth of competing bacteria. However, in many practical applications, such stringent conditions cannot be maintained and the efficacy and stability of these artificial biofilms may be challenged. In this work, biofilms were selected on low-potential anodes (-0.

An improved genetically modified Escherichia coli biosensor for amperometric tetracycline measurement.

The bacterial respiratory gene, nuoA, was previously used as a reporter gene in an amperometric, whole cell biosensor for tetracycline (Tet) detection. While the nuoA-based bioassay responded sensitively to Tet, the signal declined at high Tet concentrations, probably partly due to transgene over-expression. Also, at zero concentration of Tet, the assay registered a relatively high background signal when compared to the nuoA knockout Escherichia coli strain without the biosensor transgene construct.

Influence of anode potentials on selection of Geobacter strains in microbial electrolysis cells.

Through their ability to directly transfer electrons to electrodes, Geobacter sp. are key organisms for microbial fuel cell technology. This study presents a simple method to reproducibly select Geobacter-dominated anode biofilms from a mixed inoculum of bacteria using graphite electrodes initially poised at -0.

Appraising freeze-drying for storage of bacteria and their ready access in a rapid toxicity assessment assay.

Direct toxicity assessment (DTA) techniques seek to measure the impact of toxic chemicals on biological materials resident in the environment. This study features the use of freeze-dried bacterial cells in combination with a rapid DTA analyser, SciTOX. The effects of three factors-cryoprotectant type, bacterial strain, and storage temperature-were tested in order to validate the shelf life of the freeze-dried cells.

Comparison of three genetically modified Escherichia coli biosensor strains for amperometric tetracycline measurement.

Three separate genetic strategies, based upon the induced expression of three different genes (lacZ, selA and nuoA) were tested to provide the SciTox assay with sensitive and specific detection of the antibiotic tetracycline (Tet). All three strategies relied on gene induction from the Tn10 tetA promoter. Both lacZ and nuoA biosensors responded specifically and sensitively to sub-inhibitory concentrations of Tet.

Development and applications of whole cell biosensors for ecotoxicity testing.

Whole cell biosensors are the focus of considerable and increasing interest worldwide as methods for detecting and quantifying environmental toxicity, including biochemical oxygen demand (BOD), heavy metals, antibiotics, pesticides and herbicides. This review follows the development of whole cell biosensors from attempts to utilise changes in cellular metabolism to determine BOD and general toxicity, through the exploitation of unique metabolic pathways to detect specific toxicants, to the increasingly widespread use of genetic engineering to build new, and modify existing, sensing pathways.

Rhythmic conidiation in the blue-light fungus Trichoderma pleuroticola.

Trichoderma species conidiate in response to blue light, however, unlike in the blue-light model fungus Neurospora crassa, conidiation in Trichoderma spp. has been considered to be non-circadian. In this study we uncovered evidence for circadian conidiation in Trichoderma pleuroticola and identified orthologues of the key N.

Ambient pH intrinsically influences Trichoderma conidiation and colony morphology.

Conidiation in Trichoderma has been demonstrated to be favoured by a low ambient pH and more recently PacC (Pac1) mediated pH-regulation has been implicated in the control of conidiation. In this study, ambient pH effects on conidiation were investigated in three isolates (Trichoderma hamatum, Trichoderma atroviride and Trichoderma pleuroticola) exposed to a single blue-light burst or to mycelial injury. Disks of conidiation were observed for T.

Isolate-specific conidiation in Trichoderma in response to different nitrogen sources.

A characteristic feature of Trichoderma is the production of concentric rings of conidia in response to alternating light/dark conditions and a single ring of conidia in response to a single burst of light. In this study, conidiation was investigated in four biocontrol isolates (T. hamatum, T.

Functional stability of a hybrid anaerobic digester/microbial fuel cell system treating municipal wastewater.

A thermophilic anaerobic digester (AD) was combined with a microbial fuel cell (MFC) to evaluate whether either component had increased stability when operated in combination as a hybrid system, perturbed by the addition of acetic acid. The MFC and the anaerobic digester were able to operate effectively together. The MFC was more susceptible to high acetic acid load than the AD.

Reproduction without sex: conidiation in the filamentous fungus Trichoderma.

Trichoderma spp. have served as models for asexual reproduction in filamentous fungi for over 50 years. Physical stimuli, such as light exposure and mechanical injury to the mycelium, trigger conidiation; however, conidiogenesis itself is a holistic response determined by the cell's metabolic state, as influenced by the environment and endogenous biological rhythms.

Approaches to functional genomics in filamentous fungi.

The study of gene function in filamentous fungi is a field of research that has made great advances in very recent years. A number of transformation and gene manipulation strategies have been developed and applied to a diverse and rapidly expanding list of economically important filamentous fungi and oomycetes. With the significant number of fungal genomes now sequenced or being sequenced, functional genomics promises to uncover a great deal of new information in coming years.

Agrobacterium-mediated transformation of Sclerotinia sclerotiorum.

Ascospores from the phytopathogenic fungus Sclerotinia sclerotiorum were transformed to hygromycin B resistance by co-cultivation with Agrobacterium tumefaciens. Transformed spores germinated and grew on PDA supplemented with 100 ug/ml hygromycin B. The presence of mitotically stable hph gene integration at random sites in the genome was confirmed by PCR and Southern blot analysis.

Models of phage growth and their applicability to phage therapy.

Phage therapy is complicated by the self-replicating nature of phage. It is difficult to extrapolate from in vitro phage growth data to in vivo expectations, difficult to interpret in vivo data and difficult to generalize from one in vivo situation to another. Various generic models of phage growth have been used as the theoretical basis for understanding the kinetics of phage therapy.