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ABSTRACTCertification programmes and voluntary standards for sustainability are now a common feature of many agricultural landscapes worldwide. The rapid expansion of such programmes has only recently been accompanied by concerted attempts to assess the lived experience of enrolled producers. This article reviews empirical research assessing the impact of certification programmes on coffee smallholder livelihood assets, and presents an initial framework for both conceptualising and analysing change in livelihood assets resulting from certification. Several of the reviewed studies identified enhanced livelihood assets arising from certification under specific institutional and contextual settings, but causation was difficult to establish. A greater number of studies found either neutral or mixed impacts, and a small number reported negative impacts. While a consensus has yet to be reached regarding all livelihood impacts of certification programmes, we present a series of propositions that reflect widely reported impacts. Further findings drawn from the review include: (i) stronger pre-existing institutions within the producer community are more likely to result in benefits for individual households; (ii) the value chain structures through which certification programmes are implemented are highly varied and strongly influence livelihood outcomes; and (iii) methodologically, existing studies rarely present either reliable baseline data or a realistic control group for comparison, making causation difficult to establish.EDITED BYDagmar Mithöfer

Agricultural land has been identified as a potential source of greenhouse gas emissions offsets through biosequestration in vegetation and soil. In the extensive grazing land of Australia, landholders may participate in the Australian Government’s Emissions Reduction Fund and create offsets by reducing woody vegetation clearing and allowing native woody plant regrowth to grow. This study used bioeconomic modelling to evaluate the trade-offs between an existing central Queensland grazing operation, which has been using repeated tree clearing to maintain pasture growth, and an alternative carbon and grazing enterprise in which tree clearing is reduced and the additional carbon sequestered in trees is sold. The results showed that ceasing clearing in favour of producing offsets produces a higher net present value over 20 years than the existing cattle enterprise at carbon prices, which are close to current (2015) market levels (~$13t-1 CO2-e). However, by modifying key variables, relative profitability did change. Sensitivity analysis evaluated key variables, which determine the relative profitability of carbon and cattle. In order of importance these were: the carbon price, the gross margin of cattle production, the severity of the tree–grass relationship, the area of regrowth retained, the age of regrowth at the start of the project, and to a lesser extent the cost of carbon project administration, compliance and monitoring. Based on the analysis, retaining regrowth to generate carbon income may be worthwhile for cattle producers in Australia, but careful consideration needs to be given to the opportunity cost of reduced cattle income.

This paper explores the effect of using regional data for livestock attributes on estimation of greenhouse gas (GHG) emissions for the northern beef industry in Australia, compared with using state/territory-wide values, as currently used in Australia’s national GHG inventory report. Regional GHG emissions associated with beef production are reported for 21 defined agricultural statistical regions within state/territory jurisdictions. A management scenario for reduced emissions that could qualify as an Emissions Reduction Fund (ERF) project was used to illustrate the effect of regional level model parameters on estimated abatement levels. Using regional parameters, instead of state level parameters, for liveweight (LW), LW gain and proportion of cows lactating and an expanded number of livestock classes, gives a 5.2% reduction in estimated emissions (range +12% to –34% across regions). Estimated GHG emissions intensity (emissions per kilogram of LW sold) varied across the regions by up to 2.5-fold, ranging from 10.5kgCO2-ekg-1LW sold for Darling Downs, Queensland, through to 25.8kgCO2-ekg-1LW sold for the Pindan and North Kimberley, Western Australia. This range was driven by differences in production efficiency, reproduction rate, growth rate and survival. This suggests that some regions in northern Australia are likely to have substantial opportunities for GHG abatement and higher livestock income. However, this must be coupled with the availability of management activities that can be implemented to improve production efficiency; wet season phosphorus (P) supplementation being one such practice. An ERF case study comparison showed that P supplementation of a typical-sized herd produced an estimated reduction of 622 tCO2-eyear-1, or 7%, compared with a non-P supplemented herd. However, the different model parameters used by the National Inventory Report and ERF project means that there was an anomaly between the herd emissions for project cattle excised from the national accounts (13479tCO2-eyear-1) and the baseline herd emissions estimated for the ERF project (8896tCO2-eyear-1) before P supplementation was implemented. Regionalising livestock model parameters in both ERF projects and the national accounts offers the attraction of being able to more easily and accurately reflect emissions savings from this type of emissions reduction project in Australia’s national GHG accounts.

The grazing lands of northern Australia contain a substantial soil organic carbon (SOC) stock due to the large land area. Manipulating SOC stocks through grazing management has been presented as an option to offset national greenhouse gas emissions from agriculture and other industries. However, research into the response of SOC stocks to a range of management activities has variously shown positive, negative or negligible change. This uncertainty in predicting change in SOC stocks represents high project risk for government and industry in relation to SOC sequestration programs. In this paper, we seek to address the uncertainty in SOC stock prediction by assessing relationships between SOC stocks and grazing land condition indicators. We reviewed the literature to identify land condition indicators for analysis and tested relationships between identified land condition indicators and SOC stock using data from a paired-site sampling experiment (10 sites). We subsequently collated SOC stock datasets at two scales (quadrat and paddock) from across northern Australia (329 sites) to compare with the findings of the paired-site sampling experiment with the aim of identifying the land condition indicators that had the strongest relationship with SOC stock. The land condition indicators most closely correlated with SOC stocks across datasets and analysis scales were tree basal area, tree canopy cover, ground cover, pasture biomass and the density of perennial grass tussocks. In combination with soil type, these indicators accounted for up to 42% of the variation in the residuals after climate effects were removed. However, we found that responses often interacted with soil type, adding complexity and increasing the uncertainty associated with predicting SOC stock change at any particular location. We recommend that caution be exercised when considering SOC offset projects in northern Australian grazing lands due to the risk of incorrectly predicting changes in SOC stocks with change in land condition indicators and management activities for a particular paddock or property. Despite the uncertainty for generating SOC sequestration income, undertaking management activities to improve land condition is likely to have desirable complementary benefits such as improving productivity and profitability as well as reducing adverse environmental impact.

Soil and land-management interactions in Australian native-forest regrowth remain a major source of uncertainty in the context of the global carbon economy. We sampled soil total organic C (TOC) and soil total N (TN) stocks at 45 sites within the Brigalow ecological community of the Brigalow Belt bioregion, Queensland, Australia. The sites were matched as triplets representing three land uses, specifically: uncleared native brigalow forest (‘Remnant’); grassland pasture (‘Pasture’), derived by clearing native vegetation and maintained as pasture for a minimum of 10 years, and; regrowing native brigalow forest (‘Regrowth’, stand ages ranging from 10 to 58 years) that had developed spontaneously after past vegetation clearing for pasture establishment. Soil TOC fractions and natural abundance of soil C and N isotopes were examined to obtain insight into C and N dynamics. An updated above- and belowground carbon budget for the bioregions was generated. Average soil TOC stocks at 0–0.3-m depth ranged from 19 to 79Mgha-1 and soil TN stocks from 1.8 to 7.1Mgha-1 (2.5th and 97.5th percentiles, respectively). A trend in stocks was apparent with land use: Remnant>Regrowth ~ Pasture sites. Soil δ13C ranged from –14 to –27‰, and soil δ15N ranged from 4‰ to 17‰, in general reflecting the difference between Pasture (C4-dominated) land use and N2-fixing (C3-dominated) Remnant and Regrowth. Mid-infrared spectroscopy predicted C fractions as a percentage of soil TOC stock, which ranged from 5% to 60% (particulate), 20–80% (humus) and 9–30% (resistant/inert). The geo-referenced soil and management information we collected is important for the calibration of C models, for the estimation of national C accounts, and to inform policy developments in relation to land-resource management undertaken within the Brigalow Belt bioregions of Australia.

Beef cattle grazing is the dominant land use in the extensive tropical and sub-tropical rangelands of northern Australia. Despite the considerable knowledge on land and herd management gained from both research and practical experience, the adoption of improved management is limited by an inability to predict how changes in practices and combinations of practices will affect cattle production, economic returns and resource condition. To address these issues, past Australian and international research relating to four management factors that affect productivity and resource condition was reviewed in order to identify key management principles. The four management factors considered were stocking rates, pasture resting, prescribed fire, and fencing and water point development for managing grazing distribution. Four management principles for sound grazing management in northern Australia were formulated as follows: (1) manage stocking rates to meet goals for livestock production and land condition; (2) rest pastures to maintain them in good condition or to restore them from poor condition to increase pasture productivity; (3) devise and apply fire regimes that enhance the condition of grazing land and livestock productivity while minimising undesirable impacts; and (4) use fencing and water points to manipulate grazing distribution. Each principle is supported by several more specific guidelines. These principles and guidelines, and the supporting research on which they are based, are presented.

Pasture rest is a possible strategy for improving land condition in the extensive grazing lands of northern Australia. If pastures currently in poor condition could be improved, then overall animal productivity and the sustainability of grazing could be increased. The scientific literature is examined to assess the strength of the experimental information to support and guide the use of pasture rest, and simulation modelling is undertaken to extend this information to a broader range of resting practices, growing conditions and initial pasture condition. From this, guidelines are developed that can be applied in the management of northern Australia’s grazing lands and also serve as hypotheses for further field experiments. The literature on pasture rest is diverse but there is a paucity of data from much of northern Australia as most experiments have been conducted in southern and central parts of Queensland. Despite this, the limited experimental information and the results from modelling were used to formulate the following guidelines. Rest during the growing season gives the most rapid improvement in the proportion of perennial grasses in pastures; rest during the dormant winter period is ineffective in increasing perennial grasses in a pasture but may have other benefits. Appropriate stocking rates are essential to gain the greatest benefit from rest: if stocking rates are too high, then pasture rest will not lead to improvement; if stocking rates are low, pastures will tend to improve without rest. The lower the initial percentage of perennial grasses, the more frequent the rests should be to give a major improvement within a reasonable management timeframe. Conditions during the growing season also have an impact on responses with the greatest improvement likely to be in years of good growing conditions. The duration and frequency of rest periods can be combined into a single value expressed as the proportion of time during which resting occurs; when this is done the modelling suggests the greater the proportion of time that a pasture is rested, the greater is the improvement but this needs to be tested experimentally. These guidelines should assist land managers to use pasture resting but the challenge remains to integrate pasture rest with other pasture and animal management practices at the whole-property scale.

Etappensieg gegen Wirkstoffresistenz: Aus einer Bibliothek von über 150 1,2,4,5‐Tetraoxanen wurde ein Kandidat, RKA 182, für die präklinische Entwicklung von Malariatherapeutika selektiert. RKA 182 zeigt herausragende In‐vitro‐Aktivität gegen resistente Stämme von P. falciparumund wirkt auch gegen südostasiatische Isolate, bei denen die Artemisinin‐basierte Kombinationstherapie versagt.

OATP1B1 and OATP1B3 are major hepatic drug transporters whilst OATP1A2 is mainly located in the brain but is also located in liver and several other organs. These transporters affect the distribution and clearance of many endobiotics and xenobiotics and have been reported to have functional single nucleotide polymorphisms (SNPs). We have assessed the substrate specificities of these transporters for a panel of antiretrovirals and investigated the effects of SNPs within these transporters on the pharmacokinetics of lopinavir.

The emerging carbon economy will have a major impact on grazing businesses because of significant livestock methane and land-use change emissions. Livestock methane emissions alone account for ~11% of Australia's reported greenhouse gas emissions. Grazing businesses need to develop an understanding of their greenhouse gas impact and be able to assess the impact of alternative management options. This paper attempts to generate a greenhouse gas budget for two scenarios using a spread sheet model.The first scenario was based on one land-type ‘20-year-old brigalow regrowth' in the brigalow bioregion of southern-central Queensland. The 50 year analysis demonstrated the substantially different greenhouse gas outcomes and livestock carrying capacity for three alternative regrowth management options: retain regrowth (sequester 71.5 t carbon dioxide equivalents per hectare, CO2-e/ha), clear all regrowth (emit 42.8 t CO2-e/ha) and clear regrowth strips (emit 5.8 t CO2-e/ha). The second scenario was based on a ‘remnant eucalypt savanna-woodland' land type in the Einasleigh Uplands bioregion of north Queensland. The four alternative vegetation management options were: retain current woodland structure (emit 7.4 t CO2-e/ha), allow woodland to thicken increasing tree basal area (sequester 20.7 t CO2-e/ha), thin trees less than 10cm diameter (emit 8.9 t CO2-e/ha), and thin trees <20cm diameter (emit 12.4 t CO2-e/ha).Significant assumptions were required to complete the budgets due to gaps in current knowledge on the response of woody vegetation, soil carbon and non-CO2soil emissions to management options and land-type at the property scale. The analyses indicate that there is scope for grazing businesses to choose alternative management options to influence their greenhouse gas budget. However, a key assumption is that accumulation of carbon or avoidance of emissions somewhere on a grazing business (e.g. in woody vegetation or soil) will be recognised as an offset for emissions elsewhere in the business (e.g. livestock methane). This issue will be a challenge for livestock industries and policy makers to work through in the coming years.

There is increasing demand for cheap and rapid screening tests for soil contaminants in environmental consultancies. Diffuse reflectance spectroscopy (DRS) in the visible-near infrared (vis-NIR) and mid infrared (MIR) has the potential to meet this demand. The aims of this paper were to develop diagnostic screening tests for heavy metals and polycyclic aromatic hydrocarbons (PAH) in soil using vis-NIR and MIR DRS. Cadmium, copper, lead, and zinc were analysed, as were total PAH and benzo[a]pyrene. An ordinal logistic regression technique was used for the screening and predictions of either contaminated or uncontaminated soil at different thresholds. We calculated the rates of false positive and false negative predictions and derived Receiver Operating Characteristic curves to explore how the choice of a threshold affects their proportion. Zinc and copper had the best prediction accuracies of the heavy metals, with 89% and 85%, respectively. Cadmium and lead had the lowest prediction accuracies, with 68% and 67%, respectively. PAH predictions averaged 78.9%. With an average prediction accuracy of 79.9%, MIR analysis was only slightly more accurate than vis-NIR analysis, which had an average prediction accuracy of 77.5%. However, vis-NIR may be used in situ, thereby reducing cost and time of analysis and providing diagnosis in ‘real-time'. DRS in the vis-NIR can substantially decrease both the time and cost associated with screening for soil contaminants.

The Plasmodium falciparum dihydrofolate reductase (PfDHFR) enzyme is the target of pyrimethamine, a component of the antimalarial pyrimethamine-sulfadoxine. Resistance to this drug is associated primarily with mutations in the Pfdhfr gene. The I164L mutant allele is of particular interest, because strains possessing this mutation are highly resistant to pyrimethamine and to chlorproguanil, a component of chlorproguanil-dapsone. A recent study from Malawi reported this mutation at a prevalence of 4.7% in parasites from human immunodeficiency virus-positive pregnant women by using a real-time PCR method. These observations have huge implications for the use of pyrimethamine-sulfadoxine, chlorproguanil-dapsone, and future antifolate-artemisinin combinations in Africa. It was imperative that this finding be rigorously tested. We identified a number of critical limitations in the original genotyping strategy. Using a refined and validated real-time PCR strategy, we report here that this mutation was absent in 158 isolates from Malawi and 42 isolates from Zambia collected between 2003 and 2005.

ABSTRACTThe Plasmodium falciparumdihydrofolate reductase (PfDHFR) enzyme is the target of pyrimethamine, a component of the antimalarial pyrimethamine-sulfadoxine. Resistance to this drug is associated primarily with mutations in the Pfdhfrgene. The I164L mutant allele is of particular interest, because strains possessing this mutation are highly resistant to pyrimethamine and to chlorproguanil, a component of chlorproguanil-dapsone. A recent study from Malawi reported this mutation at a prevalence of 4.7% in parasites from human immunodeficiency virus-positive pregnant women by using a real-time PCR method. These observations have huge implications for the use of pyrimethamine-sulfadoxine, chlorproguanil-dapsone, and future antifolate-artemisinin combinations in Africa. It was imperative that this finding be rigorously tested. We identified a number of critical limitations in the original genotyping strategy. Using a refined and validated real-time PCR strategy, we report here that this mutation was absent in 158 isolates from Malawi and 42 isolates from Zambia collected between 2003 and 2005.

The development of drug resistance to affordable drugs has contributed to a global increase in the number of deaths from malaria. This unacceptable situation has stimulated research for new drugs active against multidrug-resistant Plasmodium falciparum parasites. In this regard, we show here that deshydroxy-1-imino derivatives of acridine (i.e., dihydroacridinediones) are selective antimalarial drugs acting as potent (nanomolar K(i)) inhibitors of parasite mitochondrial bc(1) complex. Inhibition of the bc(1) complex led to a collapse of the mitochondrial membrane potential, resulting in cell death (IC(50) approximately 15 nM). The selectivity of one of the dihydroacridinediones against the parasite enzyme was some 5000-fold higher than for the human bc(1) complex, significantly higher ( approximately 200 fold) than that observed with atovaquone, a licensed bc(1)-specific antimalarial drug. Experiments performed with yeast manifesting mutations in the bc(1) complex reveal that binding is directed to the quinol oxidation site (Q(o)) of the bc(1) complex. This is supported by favorable binding energies for in silico docking of dihydroacridinediones to P. falciparum bc(1) Q(o). Dihydroacridinediones represent an entirely new class of bc(1) inhibitors and the potential of these compounds as novel antimalarial drugs is discussed.

ABSTRACTAcquired resistance to therapeutic agents is a major clinical concern in the prevention/treatment of malaria. The parasite has developed resistance to specific drugs through two mechanisms: mutations in target proteins such as dihydrofolate reductase and the bc1 complex for antifolates and nathoquinones, respectively, and alterations in predicted parasite transporter molecules such as P-glycoprotein homologue 1 (Pgh1) and Plasmodium falciparumCRT (PfCRT). Alterations in the expression of Pgh1 have been associated with modified susceptibility to a range of unrelated drugs. The molecular mechanism(s) that is responsible for this phenotype is unknown. We have shown previously (A. M. Ndifor, R. E. Howells, P. G. Bray, J. L. Ngu, and S. A. Ward, Antimicrob. Agents Chemother. 37:1318-1323, 2003) that the anticonvulsant phenobarbitone (PB) can induce reduced susceptibility to chloroquine (CQ) in P. falciparum, and in the current study, we provide the first evidence for a molecular mechanism underlying this phenomenon. We demonstrate that pretreatment with PB can elicit decreased susceptibility to CQ in both CQ-resistant and CQ-sensitive parasite lines and that this is associated with the increased expression of the drug transporter Pgh1 but not PfCRT. Furthermore, we have investigated the proximal promoter regions from both pfmdr1and pfcrtand identified a number of putative binding sites for nuclear receptors with sequence similarities to regions known to be activated by PB in mammals. Whole-genome analysis has revealed a putative nuclear receptor gene, providing the first evidence that nuclear receptor-mediated responses to drug exposure may be a mechanism of gene regulation in P. falciparum.

The iron‐y of fate: Isobole analyses of fluorescently labeled antimalarial endoperoxides with chelators selective for non‐heme iron, and laser confocal microscopy studies within living malaria parasites have shown that the semisynthetic analogues of artemisinin and synthetic endoperoxides (see example) share a common mechanism of action involving chelatable‐iron‐mediated bioactivation (see images) and irreversible alkylation of parasite targets.

ABSTRACTA leading bisthiazolium drug, T16, designed to mimic choline, was shown to exert potent antibabesial activity, with 50% inhibitory concentrations of 28 and 7 nM against Babesia divergensand B. canis, respectively. T16 accumulated inside Babesia-infected erythrocytes (cellular accumulation ratio, >60) by a saturable process with an apparent Kmof 0.65 μM. Subcellular fractionation of Babesiaparasites revealed the accumulation of T16 into a low-density fraction, while in malaria-infected erythrocytes a significant fraction of the drug was associated with heme malaria pigment. T16 exerts an early and specific inhibition of the de novo biosynthesis of phosphatidylcholine both in B. divergens-and Plasmodium falciparum-infected erythrocytes. Choline accumulation into isolated Babesiaparasites was highly sensitive to inhibition by T16. These data are consistent with the hypothesis that bisthiazolium drugs target the de novo phosphatidylcholine biosynthesis of intraerythrocytic hematozoan parasites. In malaria parasites, which generate ferriprotoporphyrin IX during hemoglobin digestion, T16 binding to heme may enhance the accumulation and activity of the drug. The selectivity of accumulation and potent activity of this class of drug into parasite-infected erythrocytes offers unique advantages over more traditional antihematozoan drugs.

Widespread parasitic resistance has led to an urgent need for the development and implementation of new drugs for the treatment of Plasmodium falciparummalaria. Artemisinin and its derivatives are becoming increasingly important, used preferably in combination with a second antimalarial agent to increase the efficacy and slow the development of resistance. However, cost, production and pharmacological issues associated with artemisinin derivatives and potential partner drugs are hindering the implementation of combination therapies. This article reviews the molecular basis of the action of, and resistance to, different antimalarials and examines the prospects for the next generation of drugs to combat this potentially lethal human pathogen.

ABSTRACTThis study reports on the first characterization of the alternative NADH:dehydrogenase (also known as alternative complex I or type II NADH:dehydrogenase) of the human malaria parasite Plasmodium falciparum, known as PfNDH2. PfNDH2 was shown to actively oxidize NADH in the presence of quinone electron acceptors CoQ1and decylubiquinone with an apparent Kmfor NADH of approximately 17 and 5 μM, respectively. The inhibitory profile of PfNDH2 revealed that the enzyme activity was insensitive to rotenone, consistent with recent genomic data indicating the absence of the canonical NADH:dehydrogenase enzyme. PfNDH2 activity was sensitive to diphenylene iodonium chloride and diphenyl iodonium chloride, known inhibitors of alternative NADH:dehydrogenases. Spatiotemporal confocal imaging of parasite mitochondria revealed that loss of PfNDH2 function provoked a collapse of mitochondrial transmembrane potential (Ψm), leading to parasite death. As with other alternative NADH:dehydrogenases, PfNDH2 lacks transmembrane domains in its protein structure, and therefore, it is proposed that this enzyme is not directly involved in mitochondrial transmembrane proton pumping. Rather, the enzyme provides reducing equivalents for downstream proton-pumping enzyme complexes. As inhibition of PfNDH2 leads to a depolarization of mitochondrial Ψm, this enzyme is likely to be a critical component of the electron transport chain (ETC). This notion is further supported by proof-of-concept experiments revealing that targeting the ETC's Q-cycle by inhibition of both PfNDH2 and the bc1complex is highly synergistic. The potential of targeting PfNDH2 as a chemotherapeutic strategy for drug development is discussed.

A broad overview is presented describing the current knowledge and the ongoing research concerning the 4- aminoquinolines (4AQ) as chemotherapeutic antimalarial agents. Included are discussions of mechanism of action, structure activity relationships (SAR), chemistry, metabolism and toxicity and parasite resistance mechanisms. In discussions of SAR, particular emphasis has been given to activity versus chloroquine resistant strains of Plasmodium falciparum. Promising new lead compounds undergoing development are described and an overview of physicochemical properties of chloroquine and amodiaquine analogues is also included.

Highly active antiretroviral therapy has substantially improved prognosis in human immunodeficiency virus (HIV). However, the integration of proviral DNA, development of viral resistance, and lack of permeability of drugs into sanctuary sites (e.g., brain and lymphocyte) are major limitations to current regimens. Previous studies have indicated that the antimalarial drug chloroquine (CQ) has antiviral efficacy and a synergism with HIV protease inhibitors. We have screened a panel of antimalarial compounds for activity against HIV-1 in vitro. A limited efficacy was observed for CQ, mefloquine (MQ), and mepacrine (MC). However, marked synergy was observed between MQ and saquinavir (SQV), but not CQ in U937 cells. Furthermore, enhancement of the antiviral activity of SQV and four other protease inhibitors (PIs) by MQ was observed in MT4 cells, indicating a class specific rather than a drug-specific phenomenon. We demonstrate that these observations are a result of inhibition of multiple drug efflux proteins by MQ and that MQ also displaces SQV from orosomucoid in vitro. Finally, coadministration of MQ and SQV in CD-1 mice dramatically altered the tissue distribution of SQV, resulting in a >3-fold and >2-fold increase in the tissue/blood ratio for brain and testis, respectively. This pharmacological enhancement of in vitro antiviral activity of PIs by MQ now warrants further examination in vivo.