Lily Pereg

• University of New England

We conducted acute toxicity studies using semi-static protocols to examine the lethal responses of Australian bass and silver perch exposed to antimony (Sb) oxidation states in Sb(III) (10.5–30.5 mg L⁻¹) and Sb(V) (95.9–258.7 mg L⁻¹). Bioavailability and the effects of Sb on body ion regulation (Na, Ca, Mg, and K) were also investigated. Antimony s...

Antimony (Sb) is a priority water pollutant known to be toxic to aquatic organisms at high concentrations. Environmental exposure, however, occurs most often at sub-lethal concentrations but very limited information is available on effects of sub-lethal, chronic exposure to Sb, which hinders reliable risk assessment and the setting of protective gu...

Soil microorganisms maintain soil functions, playing a key role in nutrient cycling. However, human activities may alter ecological processes through, for instance, wildlife management tools, which affect environment conditions. Some management tools, such as diversionary feeding, are a source of organic matter and promote high animal densities in...

Microbial diversity has been well documented for the top 0–0.30 m of agricultural soils. However, spatio-temporal research into subsoil microbial diversity and the effects of agricultural management remains limited. Soil type may influence subsoil microbial diversity, particularly Vertosols. These soils lack distinct horizons and are known to facil...

Co-composting for the remediation treatment of aged polycyclic aromatic hydrocarbons (PAHs) in field contaminated soil was examined in this study. Two PAH contaminated soils collected from a manufacturing gas plant site with high PAH concentrations (184.00 ± 3.99 mg kg⁻¹ and 490.0 ± 43.53 mg kg⁻¹) were co-composted with cattle manure and wheat stra...

Productivity in agricultural ecosystems is often largely dependent on the input of nitrogen fertilizers such as urea, nitrate, and ammonia, despite the high financial costs and potential detrimental effects on the environment. Soil enrichment with organic matter, such as plant compost, straw, or manure, can enhance soil organic carbon and improve s...

Clear connections have been demonstrated between ecosystem services (ES) and human health and between soils and human health. However, despite a rich literature exploring links between ES and human health, few studies have investigated links between soil ES and human health. Viewing the relationship between soils and human health through the ES len...

Soil fertility and its productivity are the two pillars for maintaining agricultural output and it is a measure of soil performance. Growing concerns about climate change have recently focused on the fate of high-performance soils. Soil biological health is an important aspect of agricultural productivity and a global concern due to its vulnerabili...

It is essential that sampling procedures for biological measurements are done in a way that reflects the soil processes, whilst limiting sampling artefacts. In heavy clay Vertisol soils, coring lubricants are often considered necessary in order to extract and recover soil for quality and health assessments. Previous reports into the use of coring l...

Antimony (Sb) is increasing in the environment but effects of exposure in ecosystems are not well understood. The aim of this work was to examine effects of antimony exposure on the multifunctional, plant growth promoting, ubiquitous soil bacterium Azospirillum brasilense Sp7. Contaminated mine water with high Sb concentrations (0.13 ± 0.09 mg L⁻¹)...

Water shortage and soil degradation are common environmental stressors encountered in the Mediterranean area. We evaluated how different soil moisture levels, dependent on distance from drip irrigation points, impact on the biological, chemical and physical properties of citrus soil under organic and inorganic fertilization. We measured soil physic...

There are clear connections between ecosystem services (ES) and human health, as well as between soils and human health. However, studies to date have not investigated links between soil ES and human health. Viewing the relationship between soils and human health through the ES lens reveals that soil ES such as the provisioning of shelter, clothing...

The impact of soils on human health is well-documented, and the ecosystem services (ES) provided by soils are important to human health. However, previous works on soils and human health have not 0 0-approached the topic from a soil ES perspective. This paper provides examples of ways that soil ES support human health. Provisioning services ensure...

Forest fires are a regular occurrence in the Mediterranean basin. High severity fires and post-fire management can affect biological, chemical and physical properties of soil, including the composition and abundance of soil microbial communities. Salvage logging is a post-fire management strategy, which involves the removal of burnt wood from land...

This article reviews relevant literature on antimony (Sb) bioaccumulation, trophodynamics and ecotoxicity in freshwater environments, and identifies current information gaps. Both autotrophs and heterotrophs can bioaccumulate Sb, and elevated concentrations in tissues are mostly associated with anthropogenic sources. The degree of bioaccumulation i...

Antimony (Sb) is a pollutant in many jurisdictions, yet its threat to aquatic biota is unclear. Water quality guidelines (WQGs) for Sb are not well established and large uncertainty factors are commonly applied in derivation. We constructed freshwater species sensitivity distributions (SSDs) for Sb(III) using available acute toxicity data sourced f...

Aggregates play a key role in protecting soil organic carbon (SOC) from microbial decomposition. The objectives of this study were to investigate the influence of pore geometry on the organic carbon decomposition rate and bacterial diversity in both macro- (250–2000 μm) and micro-aggregates (53–250 μm) using field samples. Four sites of contrasting...

Preliminary data showing sub-soil microbial activity under continuous cotton and cotton-maize rotation crops. Microbial activity was measured as basal and substrate induced respiration, in addition to a modified EcoLog plate experiment.

Background Azospirillum spp. are the most studied plant growth-promoting bacteria (PGPB). The genus represents a common model for plant-bacteria interactions. This genus was initially isolated and tested on cereals and was subsequently commercialized. Aims Despite claims of plant specificity, particularly towards cereals, data over the past 40 yea...

Soil is the life support system of our planet. It helps make our air breathable, cleans the water we drink and supports production of the food we eat. This life support system relies upon processes that operate at spatial scales from less than a micron to over hundreds of metres or more, and over timescales from seconds to millennia.

The holistic study of soils requires an interdisciplinary approach involving biologists, chemists, geologists, and physicists amongst others, something that has been true from the earliest days of the field. In more recent years this list has grown to include anthropologists, economists, engineers, medical professionals, military professionals, soc...

Molecular methods have been used in the study of Azospirillum and other related PGPRs to carry out gene functional analysis, create gene knockouts, generate genetically engineered strains, and carry out gene expression studies. Genetic transformation has routinely been carried out using conjugation, while chromosomal modifications have been perform...

Azospirillum cellular and morphological transformation in culture as well as cyst formation, aggregation, and flocculation in response to nutritional limitations and increasing oxygen levels are discussed and typical protocols for flocculation and aggregation are presented. An overview of the mechanisms of attachment to plant roots and other surfac...

FlcA is a response regulator controlling flocculation and the morphological transformation of Azospirillum cells from vegetative to cyst-like forms. To understand the cellular responses of Azospirillum to conditions that cause morphological transformation, proteins differentially expressed under flocculation conditions in A. brasilense Sp7 and its...

There is a growing body of evidence that demonstrates the potential of various microbes to enhance plant productivity and yield in cropping systems. Realizing the potential of beneficial microbes requires an understanding of the role of microbes in growth promotion, particularly in terms of fertilization and disease control, the underlying mechanis...

This abstract will be showcasing an action research case study of the use of adaptive self-assessment modules for a second year microbiology unit at the University of New England. The MicroChallenge activity was developed as part of a teaching development project. The successful unit coordinators sought to engage students in the subject matter thro...

The holistic study of soils requires an interdisciplinary approach involving biologists, chemists, geologists, and physicists amongst others, something that has been true from the earliest days of the field. This approach has been strengthened and reinforced as current research continues to use experts trained in both soil science and related field...

Azospirillum brasilense is a nitrogen fixing bacterium that has been shown to have various beneficial effects on plant growth and yield. Under normal conditions A. brasilense exists in a motile flagellated form, which, under starvation or stress conditions, can undergo differentiation into an encapsulated, cyst-like form. Quantitative RT-PCR can be...

Black root rot is a seedling disease caused by the soil-borne fungal pathogen Thielaviopsis basicola, a species with a worldwide distribution. Diseased plants show blackening of the roots and a reduced number of lateral roots, stunted or slow growth, and delayed flowering or maturity. It was first detected in cotton in Australia in 1989, and by 200...

Crop production and agricultural practices heavily impact the soil microbial communities, which differ among varying types of soils and environmental conditions. Soil-borne microbial communities in cotton production systems, as in every other cropping system, consist of microbial populations that may either be pathogenic, beneficial or neutral with...

The development of efficient probiotic application protocols for use in marine larviculture relies on comprehensive understanding of pathogen-probiont-host interactions. The probiont combination of Pseudoalteromonas sp. PP107 and Vibrio sp. PP05 provides additive protection against vectored Vibrio owensii DY05 infection in larvae (phyllosomas) of o...

Compared with bacteria and mycorrhizal fungi, the potential to use yeasts as plant growth promoting agents has been under-exploited. We investigated the ability of the soil yeast Candida tropicalis HY (CtHY) to stimulate rice seedling growth and some of the possible mechanisms by which plant interaction may occur. Laboratory culture experiments fou...

Australian Subtropical White Syndrome (ASWS) is an infectious, temperature dependent disease of the subtropical coral Turbinaria mesenterina involving a hitherto unknown transmissible causative agent. This report describes significant changes in the coral associated bacterial community as the disease progresses from the apparently healthy tissue of...

Relative abundance of all sequenced clones from the culture-independent study, including indicator species presented in Tables 2 and 3 and additional highly abundant clones. (PDF)

Accession numbers and details of BLAST and RDP classifier analysis for culturable bacteria isolated from Turbinaria mesenterina. (PDF)

Vibrio owensii DY05 is a serious pathogen causing epizootics in the larviculture of ornate spiny lobster Panulirus ornatus. In the present study a multi-tiered probiotic screening strategy was used to identify a probiotic combination capable of protecting P. ornatus larvae (phyllosomas) from experimental V. owensii DY05 infection. From a pool of mo...

Correlation between fluorescence and concentration (CFU mL−1) of V. owensii DY05[GFP] during 24 h monoculture growth. (DOCX)

Probiotic candidate shortlist. (DOCX)

Monostrain biofilm production assay. (DOCX)

The type strain of Vibrio owensii (DY05) was isolated during an epizootic of aquaculture-reared larvae (phyllosomas) of the ornate spiny lobster (Panulirus ornatus). V. owensii DY05 was formally demonstrated to be the etiological agent of a disease causing rapid and reproducible larval mortality with pathologies similar to those seen during disease...

Inoculant plant-growth-promoting bacteria are emerging as an important component of sustainable agriculture. There is a need to develop inexpensive methods for enumerating these organisms after their application in the field, to better understand their survival and impacts on yields. Immunoblotting is one potential method to measure viable cells, b...

Thielaviopsis basicola, a soil-borne pathogen with a broad host range and a cosmopolitan distribution, is emerging as a major risk to sustainable cotton production in Australia. Previous studies suggested that host specialization has occurred making T. basicola an ideal model for a comparative proteomic analysis of strains isolated from different h...

Thielaviopsis basicola is a hemibiotroph fungus that causes black root rot disease in diverse plants with significant impact on cotton production in Australia. To elucidate how T. basicola growth and proteome are influenced by interactions with natural sources, this fungus was cultured in the presence of root extracts from non-host (wheat, hairy ve...

Since 2000, a disease displaying white-syndrome characteristics has been observed affecting corals from the genus Turbinaria in the Solitary Islands Marine Park, New South Wales, Australia. Recently termed Australian subtropical white syndrome, this disease is transmissible through direct contact and by a predatory vector, but transmission through...

Australian subtropical white syndrome (ASWS) has been observed affecting dominant coral species on subtropical reefs throughout northern New South Wales since 2000. Using replicate two metre belt transects, spatial and temporal patterns of ASWS prevalence were determined at three locations between 29.5 - 31.5° S; Solitary Islands Marine Park (SIMP)...

Since 2000, a disease displaying white-syndrome characteristics has been observed affecting corals from the genus Turbinaria in the Solitary Islands Marine Park, New South Wales, Australia. Recently termed Australian subtropical white syndrome, this disease is transmissible through direct contact and by a predatory vector, but transmission through...

A proteomic approach was used to uncover the inducible molecular defense mechanism of cotton root occurring during the compatible interaction with Thielaviopsis basicola. Microscopic observation of cotton root inoculated with a suspension of conidia showed that this necrotrophic hemibiotroph fungus interacts with the plant and completes its life cy...

Azospirillum brasilense strains benefit field crops by excreting plant growth factors, promoting root proliferation and enhancing water uptake. FlcA protein is a transcriptional response regulator of the LuxR-UhpA family, which controls flocculation of A. brasilense cells in solution and plant root surface colonisation by A. brasilense. The express...

In situ nitrogen fixation associated with the seagrass Halophila stipulacea, at the northern Gulf of Elat (Red Sea), is eight to ten times higher than that of nearby plant-free areas. A daily cycle of nitrogen fixation is evident, with rates during the day being seven times greater than during the night. Removal of seagrass leaves only from a patch...

We increased drastically the heat stability of Lac repressor (LacR) of Escherichia coli. Wild-type tetrameric LacR denatures irreversibly at 53 degrees C. Improving hydrophobic packing at the dimerisation interface by a single substitution increases LacR heat-resistance by 40 deg. C without abolishing inducer binding at high and low temperatures. T...

The effect of a mutation affecting flocculation, differentiation into cyst-like forms, and root colonization on nitrogenase expression by Azospirillum brasilense is described. The gene flcA of strain Sp7 restored these phenotypes in spontaneous mutants of both strains Sp7 and Sp245. Employing both constitutive pLA-lacZ and nifH-lacZ reporter fusion...

Genetic complementation of a spontaneous mutant, impaired in flocculation, Congo red binding, and colonization of root surface, led to the identification of a new regulatory gene in Azospirillum brasilense Sp7, designated flcA. The deduced amino acid sequence of flcA shared high similarity with a family of transcriptional activators of the LuxR-Uph...

By analogy with N2-fixing sugar cane, achieving an effective N2-fixing association between cereals and diazotrophs may require an endophytic mode of colonization, allowing better protection from oxygen and improved access to carbon substrates. Using nif A-lacZ as a genetic marker on a broad host-range plasmid pVK100, inserted into a range of free-l...

Surface colonisation of wheat roots by Azospirillum involves the polar flagellum and the production of exo-polysaccharides (Vande Broek,Vanderleyden, 1995). Bacteria on the root surface are ovoid in shape, resembling differentiated cyst-like cells.

Recent advances towards achieving significant nitrogen fixation by diazotrophs in symbioses with cereals are reviewed, referring to the literature on the evolution of effective symbioses involving rhizobia and Frankia as microsymbionts. Data indicating that strains of Acetobacter and Herbaspirillum colonizing specific cultivars of sugarcane as endo...

The Azospirillum genus comprises nitrogen-fixing bacteria which have been isolated from the roots of numerous grasses, including cereals, sugar cane and forage grasses. Among the five species known, Azospirillum brasilense is the best documented in terms of genetics and regulation of nitrogen fixation and ammonia assimilation. Several key regulator...

Halophila stipulacea beds in the northern Gulf of Elat (Red Sea) may be subdivided into three different sub-habitats, each harboring a distinct population of diazotrophs. Nitrogen (N2) fixation in the phyllosphere and in the rhizomes/upper-sediment niche was light dependent, suggesting its dependence on photosynthesis. N2 fixation in the phyllosphe...