No description available.

No description available.

No description available.

The use of microfiltration as an alternative to pasteurisation to reduce the microbial load of raw skimmed milk is a well established technology. However, its application in reducing bacteria from highly viscous dairy based solutions has not due to issues of low flux and high fouling tendency. This study involves the application of microfiltration to remove spores from high solids content Milk Protein Isolate (MPI) solutions. MPI feeds were inoculated with Bacillus mycoides spores a safer alternative to Bacillus cereus, a psychrotrophic spore forming bacteria found in dairy feeds. Suitable protocols for MPI resolubilisation, Bacillus mycoides cell and spore preparations were established and the membranes, MPI and spores were fully characterised by scanning electron microscopy (SEM), particle size distribution, rheology and pure water flux (PWF) measurements. Feed and permeate samples collected during experiments were analysed for solids content by oven drying, protein content using the Bradford assay and spore content using PetrifilmTM Aerobic count plates. To try and determine an optimum protocol for MPI filtration, a variety of filtration rig set-ups, modules and membranes were tested. Experiments were carried out at different MPI concentrations (4 – 16 wt%), cross flow velocities (CFV’s) (0.7 – 2.0 m s-1) and transmembrane pressures (TMP’s ) (1 and 2 bar). The filtration of 15 wt% MPI proved challenging. The best set of results were obtained using the 12.0 μm membrane at 1.4 m s-1, producing a 27 LMH flux, 96.5% protein transmission and a 2.1 log spore reduction. These results indicate that large pore ceramic microfiltration may be a suitable technology to replace or augment pasteurisation for high solids content dairy feeds. The effect of backwashing using different durations and frequencies was investigated. Backwashing parameters of 10 seconds every 5 minutes at 1 bar were found to be the most effective. The optimum cleaning regime found for MPI fouled ceramic membranes involved a long rinsing backflush at 1 bar, acid and alkali steps without backwashing, which produced a 99.6% flux recovery.

A concern with organic farming is for the depletion of soil phosphorus. The objectives of this study were to determine which organic management systems deplete soil phosphorus and whether arbuscular mycorrhizal fungi (AMF) could assist crops in taking up phosphorus in these systems. The research site was a 14 year-old study at Glenlea, Manitoba, having 3 different 4-year rotations under organic and conventional management: forage-grain ± manure-compost, grain-only, and a restored tall grass prairie. The modified Hedley procedure revealed organic systems to have lower concentrations of labile phosphorus than conventional but recalcitrant fractions did not differ (P < 0.05). Nitrogen was limiting in the organic grain-only rotation; phosphorus in the organic forage-grain. Mycorrhizal colonization as arbuscules was higher in organic than conventional systems (P < 0.05). To prevent phosphorus limitation, we suggest high-export organic rotations be balanced with sufficient rates of manure-compost and AMF maintained to help with phosphorus absorption. / May 2007

This work explores some of the considerations for the design and operation of a fungal spore sensor using Magnetic Resonance Force Microscopy (MRFM). This work starts by introducing the physics, components and theory of operation which make MRFM a favourable method for detecting the presence of fungal spores, which have physical dimensions in the range of a few microns to a few hundred microns. MATLAB was used to simulate changes in the dipole magnetic force which acts between a mold spore and a MEMS cantilever beam during a MRFM experiment. The dimensions, characteristics and response of the cantilever beam is estimated using MATLAB and re ned with multiple simulations in COMSOL Multiphysics. The results are two cantilever models, one made using silicon and the other silicon nitride, have approximate quality factors of 30, spring constants around 80 10^6 N/m and resonance frequencies close to 10 kHz. This work also discusses the proposed manufacturing process and considerations for the MEMS cantilever structure and the additional components of the intended prototype sensor. A sequence of operation for the initial calibration and typical operation of the spore sensor is also included in this work. The fungal spore itself is adhered within the sensing range of the sensor by using an antibody selectively chosen to bind with the targeted spore. This work concentrates on the detection of the Botryris cinerea fungal spore, however the results from this work can be easily expanded on to detect additional fungal spores by changing the monoclonal antibody used to target the other spore types

No description available.

A concern with organic farming is for the depletion of soil phosphorus. The objectives of this study were to determine which organic management systems deplete soil phosphorus and whether arbuscular mycorrhizal fungi (AMF) could assist crops in taking up phosphorus in these systems. The research site was a 14 year-old study at Glenlea, Manitoba, having 3 different 4-year rotations under organic and conventional management: forage-grain ± manure-compost, grain-only, and a restored tall grass prairie. The modified Hedley procedure revealed organic systems to have lower concentrations of labile phosphorus than conventional but recalcitrant fractions did not differ (P < 0.05). Nitrogen was limiting in the organic grain-only rotation; phosphorus in the organic forage-grain. Mycorrhizal colonization as arbuscules was higher in organic than conventional systems (P < 0.05). To prevent phosphorus limitation, we suggest high-export organic rotations be balanced with sufficient rates of manure-compost and AMF maintained to help with phosphorus absorption.

A concern with organic farming is for the depletion of soil phosphorus. The objectives of this study were to determine which organic management systems deplete soil phosphorus and whether arbuscular mycorrhizal fungi (AMF) could assist crops in taking up phosphorus in these systems. The research site was a 14 year-old study at Glenlea, Manitoba, having 3 different 4-year rotations under organic and conventional management: forage-grain ± manure-compost, grain-only, and a restored tall grass prairie. The modified Hedley procedure revealed organic systems to have lower concentrations of labile phosphorus than conventional but recalcitrant fractions did not differ (P < 0.05). Nitrogen was limiting in the organic grain-only rotation; phosphorus in the organic forage-grain. Mycorrhizal colonization as arbuscules was higher in organic than conventional systems (P < 0.05). To prevent phosphorus limitation, we suggest high-export organic rotations be balanced with sufficient rates of manure-compost and AMF maintained to help with phosphorus absorption.

Scleroderma, a genus of ectomycorrhizal (ECM) fungi, is often associated with trees in disturbed habitats and is therefore considered to be suitable for use in plantation forestry. This study investigated aspects of Scleroderma and its mycorrhizas with the view to its future use in plantation forestry in south China. Spores were chosen as inoculum as they are preferred by nursery managers in south China, due to the lack of on-site fermentation and storage facilities. To determine the need for inoculation, Eucalyptus plantations in south China were sampled for sporocarps and mycorrhizas over two years. This study revealed a low diversity of ECM fungi consisting of 15 taxa fruiting beneath Eucalyptus plantations. The most common genera were Scleroderma and Pisolithus, but they were infrequent and the extent of root colonization was poor. Bioassay trials with E. urophylla as a bait host, using soils collected from 8 eucalypt plantations, confirmed low levels of inoculum in field soil. It was concluded that introduction of suitable ECM symbionts into eucalypt nurseries in south China is desirable in the future. As the Scleroderma genus has not been well studied in Australasia or SE Asia, over 140 collections gathered mainly from eucalypt plantations in south China and south-western Australia were described using sporocarp and spore morphology. Twelve Scleroderma taxa were recognized from collections made from under eucalypt plantations in south-western Australia and 6 of these were collected from under eucalypt plantations in south China. In conjunction with classical taxonomy, 30 collections, including those used in inoculation trials, were further characterized by phylogenetic analyses of ITS or LSU rDNA sequences. These studies supported classical delineation of some Scleroderma species but not all. Although a limited number of collections were amplified, phylogenetic results showed that most collections in this study were distinct from the European and Malaysian taxa extracted from GenBank (89% bootstrap support for both LSU and ITS regions). In order to optimise spore germination and root colonization, two glasshouse trials were established to examine suitable spore density and spore storage conditions on E. globulus and E. urophylla. A spore density of 105 spores seedling-1 was identified as a suitable dose for promoting root colonization. Spores stored for 5 years at low temperate (4 0C) were almost as effective as freshly collected spores in forming mycorrhizas. As the compatibility of Scleroderma fungi with plantation trees is unknown, a glasshouse experiment examined the ability of 15 collections of Scleroderma to form mycorrhizas with seedlings of six plantation trees (Acacia mangium, A. mearnsii, E. globulus, E. urophylla, Pinus elliottii and P. radiata) in a nursery potting mix. Most collections were able to aggressively colonize eucalypts and pines, while roots of acacias were poorly colonized. As the Australian collections were more effective in colonizing short roots on eucalypts than the Chinese collections, it was concluded Scleroderma should be sourced from outside China for inoculating eucalypts in Chinese nurseries. To optimize nursery practices to meet the demand for high quality seedlings and clonal lines of E. urophylla and hybrids, for outplanting in south China, effects of rooting medium and inoculation with 6 Scleroderma collections on the growth of E. urophylla were examined in a nursery in south China. Four types of soil taken from eucalypt plantations in south China were compared to a potting mix composed of vermiculite, peat and sand. The inoculant Scleroderma fungi were able to out-compete indigenous mycorrhizal fungi in the rooting media. However, the potting mix was superior to soils both for plant growth and ECM development under nursery conditions. This research should facilitate the use of Scleroderma spores in eucalypt nurseries in south China. Spore orchards could be set up in China using Australian Scleroderma spp. from under eucalypts. Spores could be stored dry at 4 0C until they are required for inoculation in potting mixes in containerized nurseries. However, before commercial application, further work on persistence of Scleroderma in the nursery and field, and responses of trees in the field to inoculation, needs to be undertaken.