Australian Soils Research Articles

Implications of co-contamination with aged heavy metals and total petroleum hydrocarbons on natural attenuation and ecotoxicity in Australian soils

The bioremediation of historic industrial contaminated sites is a complex process. Co-contamination, often with lead which was commonly added to gasoline until 16 years ago is one of the biggest challenges affecting the clean-up of these sites. In this study, the effect of heavy metals, as co-contaminant, together with total petroleum hydrocarbons (TPH) is reported, in terms of remaining soil toxicity and the structure of the microbial communities. Contaminated soil samples from a relatively hot and dry climate in Western Australia were collected (n = 27). Analysis of soils showed the presence of both contaminants, TPHs and heavy metals. The Microtox test confirmed that their co-presence elevated the remaining ecotoxicity. Toxicity was correlated with the presence of lead, zinc and TPH (0.893, 0.599 and 0.488), respectively, assessed using Pearson Correlation coefficient factor. Next Generation Sequencing of soil bacterial 16S rRNA, revealed a lack of dominate genera; however, despite the variation in soil type, a few genera including Azospirillum spp. and Conexibacter were present in most soil samples (85% and 82% of all soils, respectively). Likewise, many genera of hydrocarbon-degrading bacteria were identified in all soil samples. Streptomyces spp. was presented in 93% of the samples with abundance between 7% and 40%. In contrast, Acinetobacter spp. was found in only one sample but was a dominant member of (45%) of the microbial community. In addition, some bacterial genera were correlated to the presence of the heavy metals, such as Geodermatophilus spp., Rhodovibrio spp. and Rubrobacter spp. which were correlated with copper, lead and zinc, respectively. This study concludes that TPH and heavy metal co-contamination significantly elevated the associated toxicity. This is an important consideration when carrying out risk assessment associated with natural attenuation. This study also improves knowledge about the dynamics of microbial communities in mixed contamination scenarios.

'Racy of the Soil': Ian Mudie, Right-Wing Nationalism, and the South Australian Soil Erosion Crisis

Abstract Ian Mudie was an Adelaide-based freelance journalist, short story and history writer, and most notably a passionate and political poet. During the 1930s and 1940s the degradation of South Australian agricultural and pastoral soil inspired Mudie to evoke soil in his poetry. Soil also proved a useful metaphor which Mudie could deploy in aid of his right-wing political stance. Critics and historians have described Mudie either as a 'nationalist or propagandist' and a 'hectoring' nationalist, or, alternatively, as an early conservationist and even a 'proto ecologist'; none address the intersection of environmental concern and right-wing nationalism in his poetry and politics. This article will interrogate the relationship between these two ideologies in Mudie's work. Despite echoes of Nazi 'blood and soil' ideology, Mudie's soil erosion poetry was primarily the product of his settler imagination, and resonated with 'cultural nationalists' in the Australian literary community.

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Front cover: The cover image taken of the Australian cockroach species Macropanesthia rhinoceros is based on the Research Paper Multiple abiotic factors correlate with parallel evolution in Australian soil burrowing cockroaches by Perry G. Beasley-Hall et al. DOI: 10.1111/jbi.13233. Photo Credit: Yi-Kai Tea, University of Sydney.

Impact of waste-derived organic and inorganic amendments on the mobility and bioavailability of arsenic and cadmium in alkaline and acid soils.

In agriculture, more and more frequently waste-derived amendments are applied to soil to improve physical and chemical properties. Nevertheless, in soils polluted by potentially toxic metal(loid)s, this agricultural practice may significantly affect the mobility and bioavailability of pollutants modifying the risks for biota and human health. This work was aimed to assess the influence of poultry manure, biochar and coal fly ash on the mobility and bioavailability of As and Cd spiked in two Australian soils with different pH and texture: Mount Gambier (MGB)-alkaline sandy clay loam and Kapuda (KPD)-acid loamy sand. After 4weeks of incubation from spiking and another 4weeks from amendment addition, the soils were analysed for pH and amounts of As and Cd in pore-water and following 1M NH4NO3 extraction. Bioavailable amounts were assessed by plant uptake, using Zea mays L. as test crop. In the alkaline MGB soil, the availability of Cd was reduced, while that of As increased. An opposite behaviour was observed in the acid KPD soil. All amendments, when added to KPD soil, increased pH and consequently reduced the mobility of Cd and increased the mobility of As. In MGB, the amendment addition had an effect only on As mobility and bioavailability, which increased likely as a result of the increased competition for adsorption with DOC released by organic compounds. These trends were confirmed by the amounts of Cd and As uptaken by maize plants.

High-resolution mapping of acid sulfate soils in Northern Australia through predictive models

Acid sulfate soils can form when pyrite-rich marshes are drained or tidal influence decreases, naturally or anthropogenically. Often they are vegetated by mangroves, serve as important aquatic bird habitats, and harbor unique microbial biodiversity. They limit coastal development potential. The current best map of Australian acid sulfate soils is based on expert interpretation of soil surveys, most at 1:100,000 scale. In the current study, we attempted the first predictive spatial modeling to map acid sulfate soils and soil sulfur concentration on a 90-m grid. We use 34 national environmental 90-m grids and 614 observations on the presence/absence of acid sulfate soils to train a machine learning algorithm, random forests, to predict the location of acid sulfate soils across three regions of Northern Australia. We use the same environmental data and 1315 measurements of total elemental sulfur at 60–80 cm depth across Australia to train another random forest model to predict the spatial pattern of sulfur concentrations in the three regions. The model for acid sulfate soils is better than that for sulfur but both related maps showed that high sulfur concentrations generally coincide with the predicted presence of acid sulfate soils. This coincidence between the predicted occurrence of acid sulfate soils and sulfur concentrations confirms the modeling approach presented here was reliable and could be applied to map acid sulfate soils at high resolution globally.

Allocating soil profile descriptions to a novel comprehensive soil classification system

Previous work has been put into the creation of a comprehensive soil classification system (CSCS) using a harmonised dataset of 23 soil properties at 18 depth intervals. The classification consists of selected soil taxa from the US Soil Taxonomy, World Reference Base for Soil Resources, the Australian Soil Classification, and the New Zealand Soil Classification. In this paper, the CSCS was tested for allocation using data for from 44 soil profiles collected in Iran. A distance-based algorithm was used to allocate and name the soil profiles according to the CSCS. It was found that 36 Iranian soil profiles are close to the existing taxa of the CSCS in the taxonomic space. Three Iranian profiles with distances between 25 and 30 taxonomic units to the closest CSCS taxa were added to the CSCS and assigned with new systematic names. Allocating the remaining 5 Iranian taxa would require regenerating the nomenclature system. The CSCS has shown advantages for allocating soil profiles from other regions of the world other than the USA, Australia and New Zealand. It also enables cross-referencing with existing soil classification systems. In the future, the CSCS can be further improved by adding taxa from other global or regional soil classification systems.

Effect of applied potassium concentration on clay dispersion, hydraulic conductivity, pore structure and mineralogy of two contrasting Australian soils

Re-use of industrial and agricultural wastewater for irrigation can increase the concentration of potassium ions in soil solution and affect soil structural stability. However, investigations of clay dispersion have traditionally focused on soils with high exchangeable sodium. The objective of this study was to quantify the effects of potassium application on physical, chemical and mineralogical properties of two contrasting soils from South Australia. This work combines traditional soil and clay analysis methods with a range of additional techniques, including, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and modeling for characterizing and quantifying the movement of different forms of potassium in soil. In laboratory studies, soils were treated with varying amounts of potassium and the measurements were made on the range of soil/clay properties before and after treatments. The results show that applied potassium can cause dispersion of soil but to a lesser extent than sodium. Potassium cations also could increase soil hydraulic conductivity (HC) to some extent when applied to a soil with high sodium content by substituting the Na+ on exchange sites. Potassium could be fixed by clay minerals, changing their composition, decreasing cation exchange capacity and increasing mineral potassium content. This increase was confirmed by the decomposition of XRD diagrams and chemical analysis, consistently showing the increases in amount of mica/illite clay minerals in soils treated with potassium rich solutions. The dynamic of “illitisation” can be monitored by XRD analysis both qualitatively and quantitatively. X-ray computed tomography (CT) scanning of the soil columns has allowed visualization and quantification of the changes in pore system occurred due to the application of potassium.

Multiple abiotic factors correlate with parallel evolution in Australian soil burrowing cockroaches

AbstractAimThe ways in which abiotic factors contribute to parallel evolution—the evolution of similar, derived phenotypes in independent, closely related lineages—remain understudied. Australian cockroaches of the subfamilies Panesthiinae (“wood feeders”) and Geoscapheinae (“soil burrowers”) are two closely related groups that provide a striking example of parallel evolution of burrowing behaviour. The ancestral wood‐feeding panesthiines migrated from Asia ~20 million years ago before soil burrowing was independently acquired multiple times in the derived geoscapheines. Here, we investigate whether specific abiotic factors were associated with the parallel evolution of soil burrowing behaviour, and whether divergence events of geoscapheines from panesthiine ancestors are consistent with niche conservatism or divergence.LocationThe Australian mainland, including the areas in which selected Australian Panesthiinae and Geoscapheinae cockroach species are distributed.MethodsWe generated environmental niche models for members of the Australian Geoscapheinae and Panesthiinae using presence‐only data and abiotic variables related to temperature, precipitation, and soil composition from BioClim and the Australian Soil Resource Information System. We used an existing phylogenetic framework to compare environmental niche models and tested for niche conservatism versus divergence. Morphological convergence was assessed by a regression analysis and principal components analysis of leg segment and body dimensions in soil burrowers and wood feeders.ResultsWe found no relationship between niche similarity and time since divergence, and only limited evidence for phylogenetic signal with respect to the environmental variables examined. We found that soil burrowing behaviour is consistently correlated with thirteen abiotic factors associated with aridity, including a wider range of temperatures and lower precipitation levels. Evidence for convergence in leg morphology and body dimensions across soil burrowers was found.Main conclusionsOur results are consistent with soil burrowing behaviour evolving in response to ancient aridification events following the arrival of the Panesthiinae in Australia. Our results suggest a scenario of niche divergence between soil burrowers and each of their wood feeding sister taxa. There is evidence for morphological convergence on a “shovel‐like” protibiotarsus in the Geoscapheinae that would aid in burrowing into soil.

Can next-generation soil data products improve soil moisture modelling at the continental scale? An assessment using a new microclimate package for the R programming environment

Accurate models of soil moisture are vital for solving core problems in meteorology, hydrology, agriculture and ecology. The capacity for soil moisture modelling is growing rapidly with the development of high-resolution, continent-scale gridded weather and soil data together with advances in modelling methods. In particular, the GlobalSoilMap.net initiative represents next-generation, depth-specific gridded soil products that may substantially increase soil moisture modelling capacity. Here we present an implementation of Campbell’s infiltration and redistribution model within the NicheMapR microclimate modelling package for the R environment, and use it to assess the predictive power provided by the GlobalSoilMap.net product Soil and Landscape Grid of Australia (SLGA, ∼100 m) as well as the coarser resolution global product SoilGrids (SG, ∼250 m). Predictions were tested in detail against 3 years of root-zone (3–75 cm) soil moisture observation data from 35 monitoring sites within the OzNet project in Australia, with additional tests of the finalised modelling approach against cosmic-ray neutron (CosmOz, 0–50 cm, 9 sites from 2011 to 2017) and satellite (ASCAT, 0–2 cm, continent-wide from 2007 to 2009) observations. The model was forced by daily 0.05° (∼5 km) gridded meteorological data. The NicheMapR system predicted soil moisture to within experimental error for all data sets. Using the SLGA or the SG soil database, the OzNet soil moisture could be predicted with a root mean square error (rmse) of ∼0.075 m3 m−3 and a correlation coefficient (r) of 0.65 consistently through the soil profile without any parameter tuning. Soil moisture predictions based on the SLGA and SG datasets were ≈ 17% closer to the observations than when using a chloropleth-derived soil data set (Digital Atlas of Australian Soils), with the greatest improvements occurring for deeper layers. The CosmOz observations were predicted with similar accuracy (r = 0.76 and rmse of ∼0.085 m3 m−3). Comparisons at the continental scale to 0–2 cm satellite data (ASCAT) showed that the SLGA/SG datasets increased model fit over simulations using the DAAS soil properties (r ∼ 0.63 &rmse 15% vs. r 0.48 &rmse 18%, respectively). Overall, our results demonstrate the advantages of using GlobalSoilMap.net products in combination with gridded weather data for modelling soil moisture at fine spatial and temporal resolution at the continental scale.

A Historical Perspective on WRESAT, the First Satellite Launched from Australian Soil

Just over fifty years ago, on 29 November 1967 at 2:19 pm (local time), a small scientific satellite named the Weapons Research Establishment SATellite (WRESAT) was launched from Woomera, South Australia. It had been designed and constructed by engineers, scientists and technicians from the Weapons Research Establishment, Salisbury, South Australia; it had a payload of scientific instruments put together by the Physics Department at Adelaide University; and it was sent into orbit at the sharp end of a modified Redstone rocket, a gift from the United States. All of this was achieved in less than 12 months; and it made Australia the third country in the world to launch a satellite into space from its own territory, after the USSR and the USA. This paper is the author's personal account of his part in the project, where he was involved first with the satellite's telemetry system and then with a temporary extension to Oodnadatta of Woomera's flight safety system. The paper goes on to describe events following the successful launch, and the celebration of the 50th anniversary in 2017. Finally, there is a discussion of the politics and technologies behind WRESAT.

A Historical Perspective on WRESAT, the First Satellite Launched from Australian Soil

Just over fifty years ago, on 29 November 1967 at 2:19 pm (local time), a small scientific satellite named the Weapons Research Establishment SATellite (WRESAT) was launched from Woomera, South Australia. It had been designed and constructed by engineers, scientists and technicians from the Weapons Research Establishment, Salisbury, South Australia; it had a payload of scientific instruments put together by the Physics Department at Adelaide University; and it was sent into orbit at the sharp end of a modified Redstone rocket, a gift from the United States. All of this was achieved in less than 12 months; and it made Australia the third country in the world to launch a satellite into space from its own territory, after the USSR and the USA. This paper is the author's personal account of his part in the project, where he was involved first with the satellite's telemetry system and then with a temporary extension to Oodnadatta of Woomera's flight safety system. The paper goes on to describe events following the successful launch, and the celebration of the 50th anniversary in 2017. Finally, there is a discussion of the politics and technologies behind WRESAT.

A nomenclature algorithm for a potentially global soil taxonomy

Previous work has been put into the creation of a global soil taxonomy using a harmonised dataset of 23 soil properties at 18 depth intervals. The taxonomy consisted of selected soil taxa from the US Soil Taxonomy, World Reference Base for Soil Resources, the Australian Soil Classification, and the New Zealand Soil Classification. In this paper, a nomenclature algorithm was proposed for this established comprehensive taxonomy. Firstly, a Ward dendrogram was calculated from a weighted distance matrix determined from principal components of the taxa. This dendrogram was then cut at three levels, creating 15 groups, 86 subgroups, and 493 sub-subgroups at tiers 1, 2 and 3, respectively. A sequence of consonants was used to name the taxa at each tier alphabetically with “A” and “E” inserted between the consonants of tiers 2 and 3 and “OZEM” appended after the consonants of tier 1. In addition, a distance-based algorithm was used to allocate and name 10 unknown soil profiles to the comprehensive soil taxonomy. It was concluded that the nomenclature algorithm can be easily disaggregated by computer and can be used to understand the inter-relationships between soil profiles from different classification systems. In the future, there is a need to include other soil classification systems to the comprehensive system and assign different weights to the soil properties and depths used to construct the comprehensive soil classification system.

Updating a national soil classification with spectroscopic predictions and digital soil mapping

Traditional soil maps have helped us to better understand soil, to form our concepts and to teach and transfer our ideas about it, and so they have been used for many purposes. Although, soil maps are available in many countries, there is a need for them to be updated because they are often deficient in that their spatial delineations and their descriptions are subjective and lack assessments of uncertainty. Updating them is a priority for federal soil surveys worldwide as well as for research, teaching and communication. New data from sensors and quantitative ‘digital’ methods provide us with the tools to do so. Here, we present an approach to update large scale, national soil maps with data derived from a combination of traditional soil profile classifications, classifications made with visible–near infrared (vis–NIR) spectroscopy, and digital soil class mapping (DSM). Our results present an update of the Australian Soil Classification (ASC) orders map. The overall error rate of the DSM model, tested on an independent validation set, was 55.6%, and a few of the orders were poorly classified. We discuss the possible reasons for these errors, but argue that compared to the previous ASC maps, our classification was derived objectively, using currently best available data sets and methods, the classification model was interpretable in terms of the factors of soil formation, the modelling produced a 1×1km resolution soil map with estimates of spatial uncertainty for each soil order and our map has no artefacts at state and territory borders.

Comparisons between USDA soil taxonomy and the Australian Soil Classification system II: Comparison of order, suborder and great group taxa

Soil taxonomies over the world are incongruent- based on different tiers and different sets of properties. This second paper is concerned with understanding the relationships of each tier (Order, Suborder and Great Group) in both Soil Taxonomy (ST) and the Australian Soil Classification system (ASC) using mean nearest neighbour distances and convex hull areas in two principal component dimensions. It is determined that in most instances, convex hull comparisons using only two principal components, representing 30% of the variation in the data describe much of the variability between and within the orders, suborders and great groups of each classification system. These are useful for visual comparisons of taxa at various levels. Mean nearest-neighbour distances can include all 414 variables if necessary, which is more rigorous but complex. Both distance calculations and convex hulls highlight the same associations between taxa from ASC and ST. Both these methods demonstrate the robust soil classification capability of the ST and the ASC, but with convex hull sizes and nearest-neighbour distances that are smaller, the ASC proves to be slightly more coherent. The two systems occupy somewhat different areas in PC space, and ST covers a larger overall area, demonstrating that ASC is a purpose-built classification for Australian conditions while ST Is a more general system that can cover a wider variety of soils and management issues. We also show that great groups in ST are at about the same level of taxonomic generalization as great groups of the ASC. Combining the best elements and taxa of both these systems would be a positive step in the creation of a comprehensive system.

Peter Corrigan, the Bodgie Wolf, and Other Larrikin Tygers of Wrath

In the face of being “othered” over issues to do with cultural isolation and derivation, a new generation of Australian architects arose in the 1970s, celebrating Australia’s distinctive regionalism. This regionalist current chimed with the growth of the postmodern movement, which, had done much to liberate the Australian architect from the so-called “cultural cringe,” as he or she no longer felt that they had to hobble after what was happening elsewhere. Among this new cohort of architects, the work of Peter Corrigan is notable for advocating a mongrel postmodern architecture that was positively and distinctively Australian, sampling from the ordinary and dreary Australian suburbs. This article seeks to clarify the architectural quest for an Australian identity in Corrigan’s work, by exploring in depth the interdisciplinary and transatlantic transfer of ideas from theatre to architecture. Corrigan had a long-standing engagement with stage design, and this article will argue that his involvement in “New Wave theatre,” notably the Australian Performing Group (APG), and the appropriation of concepts from directors and playwrights like John Vaccaro, John Romeril, Jerzy Grotowski, Casper Neher, and Bertold Brecht, determined how he transplanted postmodern ideas onto Australian soil.

LNG as marine fuel – where technology meets logistics

Following the establishment of the ‘LNG Marine Fuel Institute’ in Australia and research projects on alternative fuelling of ore carriers operating out of Australia, the focus of the marine and oil and gas industry is turning increasingly towards the adoption of liquefied natural gas (LNG) as a fuel oil. The development of LNG bunkering facilities on Australian soil followed. For LNG to be a viable option for deep sea shipping, it is all about infrastructure, technology and the human element. Thus far, LNG as fuel oil was only applied on LNG carriers; outside of that, LNG has mainly been used for short sea applications, which are tightly controlled from a technical and human element perspective mainly through shore-to-ship custody transfer. For deep sea shipping however, the infrastructure needs to be in place to allow regular refuelling options on various global shipping trade routes. It is anticipated that for deep sea shipping, the main mode of LNG fuelling will be through ship-to-ship custody transfers with required risk management. LNG bunkering technology standards and procedures are largely maturing, and efforts are underway to harmonise these standards globally to allow for flexible fuelling locations for ships traversing large distances. The remaining challenge will be to enhance a ship’s crew competence. The level of sophistication required of a crew for LNG bunkering is not something attained thus far in conventional oil bunkering and needs to be addressed. Continuous Competence Management Systems taking LNG cargo trading vessel experience into account, together with the ‘Standards of Training Certification and Watchkeeping for Seafarers’ requirements, is vital for the safe development of gas bunkering for deep sea shipping.

IT-technologies in soil Informatics and Russian agribusiness

One of the promising areas associated with a large amount of information on the properties, characteristics and classification of soils is soil Informatics. Its appearance has allowed soil scientists, farmers and environmentalists to process data; to model soil processes, to make operational decisions on land use; implement systems to assess fertility, control of technological processes in agriculture. Currently multinational and global information systems are used, which contain data on soil profiles of many countries: European Soil Database, Europe; SOTER, global soil information system and others. Information systems at the national level study the soil characteristics of one country: Australian Soil Resource Information System; National Soil Information System (USA) and others. In order to generalize process and preserve information about soils of Russia accumulated by long-term research, a nationwide Soil-geographical database is being developed in our country. To optimize the agricultural activity of certain regions of the country, regional information systems are developed - Accounting and monitoring of agricultural lands of the Novosibirsk region, geoinformation system of the Tyumen region and others. Modern soil information systems, for the most part, are implemented through the use of the GeoRSS standard, which is based on a hypertext providing information on the Internet.

Chronic and reproductive toxicity of cadmium, zinc, and lead in binary and tertiary mixtures to the earthworm (Eisenia fetida)

The presence of one metal can alter the toxicity of another metal by having an additive, synergistic, or antagonistic impact. Mixed metal pollution has clear ecological consequences. The importance of use of earthworms for ecological health monitoring is recognized widely. This study investigated the effect of binary and tertiary metal mixtures on the toxicity, bioaccumulation, and reproduction of the Eisenia fetida in different South Australian soils. The end points used in this 56-day reproduction study were avoidance behavior, worm mortality, weight loss, reproduction, and metal (Cd, Zn, and Pb) bioaccumulation. The three soils (acidic, neutral, and alkaline) were spiked with selected binary and tertiary concentration mixtures that considered the soil quality guideline values, EC50 and LC50 values for Cd, Zn, and Pb obtained from the previous single metal earthworm experiments done by the authors. In acidic soil, Zn and Cd constituted the most toxic metal combination to earthworms. However, in contrast to this observation, the same metal combination was the least toxic one to earthworms in neutral and alkaline soils. For Zn and Pb spiked soils, relationships between soil and internal metal concentrations were found with R 2 = 0.63, r = 0.8, and R 2 = 0.94, p < 0.01, respectively, for Zn and Pb. This study indicates that earthworms have high tendency to bioaccumulate heavy metals in their tissues and hence serves as ecological indicators of soil heavy metal contamination. The highest bioaccumulation factor (0–9) was evident for Cd in contaminated soils. This study demonstrated the role of soil edaphic factors and metal-metal interactions in the toxicity of metal mixtures to E. fetida. In Zn and Pb binary mixture spiked acidic soil, mortality of 60% was recorded even when the Pb and Zn concentrations were below the Canada and Dutch EIL (ecological investigational levels) values. This indicates the current guideline values are not safe for mixed metal toxicity. Therefore, care must be taken when predicting metal toxicities in mixed metal contaminated soils.

Effects of long-term cultivation on phosphorus (P) in five low-input, subtropical Australian soils

Despite the importance of P for cropping, there remains uncertainty regarding the effects of long-term cropping on P behaviour in soils. Using five soils (Billa Billa, Cecilvale, Riverview, Thallon, and Waco) from subtropical Australia cropped for ≤70y with low rates of P-fertilizer inputs, changes in soil P (organic, inorganic, and total) were assessed and related to P removal in wheat grain. For four of the five soils, concentrations of organic P decreased significantly with increasing period of cropping, decreasing between 20 and 36%. In contrast, concentrations of inorganic P generally remained relatively constant. Despite the decrease in organic P, the C/P ratio remained relatively constant in all five soils (average of 99), indicating that organic P is protected within the soil organic matter in a manner similar to the organic C. Furthermore, although increasing period of cropping decreased soil organic P concentrations, grain P concentrations decreased significantly only for Billa Billa and Thallon. Finally, although the rate of P removal in grain was low (1.6 to 9.3kgha−1y−1), the rate of removal exceeded inputs from P-containing fertilizers. Thus, there is a need to consider the long-term P-fertilization to ensure adequate P nutrition of the crops. This study provides important information regarding changes in P within long-term cropping systems and will assist in their sustainable management.

Amycolatopsins A-C: antimycobacterial glycosylated polyketide macrolides from the Australian soil Amycolatopsis sp. MST-108494.

A southern Australian soil isolate, Amycolatopsis sp. MST-108494, was subjected to a panel of fermentation and media optimization trials, supported by analytical chemical profiling, to detect and enhance production of a rare class of secondary metabolites. Chemical fractionation of two complementary fermentations yielded three new polyketides, identified by detailed spectroscopic analysis as the glycosylated macrolactones, amycolatopsins A (1), B (2) and C (3), closely related to the ammocidins and apoptolidins. Amycolatopsins 1 and 3 selectively inhibited growth of Mycobacterium bovis (BCG) and Mycobacterium tuberculosis (H37Rv) when compared with other Gram-positive or Gram-negative bacteria, with 3 exhibiting low levels of cytotoxicity toward mammalian cells. Thus, our data reveal promising structure activity relationship correlations where the antimycobacterial properties of amycolatopsins are enhanced by hydroxylation of the 6-Me (that is, 1 and 3), whereas mammalian cytotoxicity is decreased by hydrolysis of the disaccharide moiety (that is, 3).