https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33414 Wed 31 Oct 2018 14:51:44 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27108 Wed 11 Apr 2018 12:13:49 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38372 Wed 01 Sep 2021 12:12:32 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33185 Eisenia fetida in spiked soils by exposing the worms for 28 days following standard procedures. The toxicity studies revealed that Hg exerted less lethal effect on earthworms in acidic soil with higher organic carbon (S-3 soil) where water soluble Hg recovery was very low compared to the water soluble Hg fractions in soils with less organic carbon and higher pH (S-1 and S-2 soils). The concentrations of total Hg that caused 50 % lethality to E. fetida (LC50) after 28 days of exposure in S-1, S-2 and S-3 soils were 152, 294 and 367 mg kg⁻¹, respectively. The average weight loss of E. fetida in three soils ranged from 5 to 65 %. The worms showed less weight loss in the organic carbon-rich soil (S-3) compared to less organic carbon containing soils (S-1 and S-2). The bioconcentration of Hg in E. fetida increased with increased Hg concentrations. The highest bioaccumulation took place in the acidic soil with higher organic carbon contents with estimated bioaccumulation factors ranging from 2 to 7.7. The findings of this study will be highly useful for deriving a more robust soil ecological guideline value for Hg.]]> Tue 11 Sep 2018 12:15:44 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:40048 Thu 21 Jul 2022 10:30:22 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48966 Thu 20 Apr 2023 10:29:33 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26517 Thu 05 Oct 2023 16:40:22 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31523 Sphingobium SA2 and nutrient amendment. In a field with ~ 280 mg/kg Hg, 60% of Hg was removed by bio-augmentation in 7 days, and the removal was improved when nutrients were added. Whereas in artificially spiked soils, with ~ 100 mg/kg Hg, removal due to bio-augmentation was 33 to 48% in 14 days. In the field contaminated soil, nutrient amendment alone without bio-augmentation removed 50% of Hg in 28 days. Nutrient amendment also had an impact on Hg remediation in the spiked soils, but the best results were obtained when the strain and nutrients both were applied. The development of longer root lengths from lettuce and cucumber seeds grown in the remediated soils confirmed that the soil quality improved after bioremediation. This study clearly demonstrates the potential of Hg-reducing bacteria in remediation of Hg-contaminated soils. However, it is desirable to trap the volatilized Hg for enhanced bioremediation.]]> Sat 24 Mar 2018 08:43:51 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31459 Sphingobium SA2. The sensing element contained green fluorescence protein gene gfp fused to short segment of merA gene of Sphingobium SA2. The sensing element was introduced into electro-competent cells of Sphingobium SA2, where it integrated into the bacterial DNA due to homologous recombination. The transformed cells were able to produce green fluorescence in 5 h in the presence of nano-molar concentrations of mercury. A linear positive correlation was observed between 0–40 nm Hg and fluorescence intensity.]]> Sat 24 Mar 2018 08:43:50 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30187 50 and MIC values. Estimated EC₅₀ and MIC values in nutrient-rich media and low nutrient media had the following respective recordings - 22.6 mg L^-1; 23.1 mg L^-1 and 1.4 mg L^-1 and 1.7 mg L^-1. The isolate was able to volatilize inorganic mercury demonstrated by a modified photographic film experiment and subsequently revealed its ability to remove mercury from the solution. The ICP-QQQ-MS analysis of SE1 inoculated solution showed almost 60% of 1.5 mg L^-1 mercury was volatilized in 6 h and almost 40% were accumulated in cell pellets. The mercuric reductase gene merA was identified in the genome of isolate SE1 and sequenced. The deduced amino acid sequence of merA gene indicated a sequence homology with different organisms from the alpha proteobacteria group and eukaryotic fungi. merA encoded enzyme mercuric reductase activity was evident in the crude protein of the isolate. The isolate's ability to resist Hg, it's Hg volatilization potential and the presence of merA gene and mercuric reductase enzyme demonstrates the potential application of this strain in mercury bioremediation.]]> Sat 24 Mar 2018 07:41:31 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29927 Cucumis sativa L. (cucumber) focusing primarily on pore-water Pb data from 10 different soils after 12 weeks ageing. Phytotoxicity expressed in terms of Pb²⁺ was observed to occur in the nanomolar range in neutral to alkaline soils (EC50 values 90 to 853 nM) and micromolar levels for acidic soils (EC50 values 7.35 to 9.66 μM). Internal Pb concentrations relating to toxicity (PT50) in roots and shoots also decreased with increasing pore-water pH (R² = 0.52 to 0.53). From a series of dose-response studies, we developed transfer functions predicting Pb uptake in C. sativa and we validated these functions with long-term Pb contaminated soils. The significant independent parameters were pore-water Pb²⁺ and dissolved Pb plus dissolved organic carbon (DOC). The observed RMSE for the Pb-DOC model and Pb²⁺ were 2.6 and 8.8, respectively. The Pb-DOC model tended to under-predict Pb, whilst Pb²⁺ tended to over-predict accumulation despite reasonable RMSE values. Further validation is needed in soils with higher pore-water Pb solubility.]]> Sat 24 Mar 2018 07:30:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30473 Iseilema membranaceum (Barcoo), Dichanthium sericeum (Queensland Blue) and Sporobolus africanus (Tussock) were grown in three different soils spiked with different concentrations of inorganic mercury and the root elongation was monitored up to 28 days following the germination. Results showed that mercury at certain concentrations significantly inhibited the root growth of all three tested native grasses grown in three soils, however, the toxicity was less in the soil with high organic carbon content and acidic pH. The calculated EC₅₀ values ranged from 10 to 224 mg/kg total Hg in soil. However, the EC₁₀ values indicated that existing guideline values for mercury may be of protective to the native Australian vegetation. Considering their tolerance to soil mercury, these grass species have the potential for their use in rehabilitation of mercury contaminated sites.]]> Sat 24 Mar 2018 07:24:16 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26518 Sat 24 Mar 2018 07:23:24 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24015 Sphingobium and Sphingomonas of α-proteobacteria group. However, the isolate formed a distinct phyletic line with the genus Sphingobium suggesting the strain belongs to Sphingobium sp. Toxicity studies indicated resistance to high levels of mercury with estimated EC₅₀ values 4.5 mg L^-1 and 44.15 mg L^-1 and MIC values 5.1 mg L^-1 and 48.48 mg L^-1 in minimal and rich media, respectively. The strain SA2 was able to volatilize mercury by producing mercuric reductase enzyme which makes it potential candidate for remediating mercury. ICP-QQQ-MS analysis of Hg supplemented culture solutions confirmed that almost 79% mercury in the culture suspension was volatilized in 6 h. A very small amount of mercury was observed to accumulate in cell pellets which was also evident according to ESEM-EDX analysis. The mercuric reductase gene merA was amplified and sequenced. The deduced amino acid sequence demonstrated sequence homology with α-proteobacteria and Ascomycota group.]]> Sat 24 Mar 2018 07:16:45 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24022 Sat 24 Mar 2018 07:16:44 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33743 Sphingopyxis belongs to the Sphingomonadaceae family of the α-Proteobacteria group. The isolate showed high resistance to mercury with estimated concentrations of Hg that caused 50% reduction in growth (EC₅₀) of 5.97 and 6.22 mg/L and minimum inhibitory concentrations (MICs) of 32.19 and 34.95 mg/L in minimal and rich media, respectively. The qualitative detection of volatilized mercury and the presence of mercuric reductase enzyme proved that the strain SE2 can potentially remediate mercury. ICP-QQQ-MS analysis of the remaining mercury in experimental broths indicated that a maximum of 44% mercury was volatilized within 6 hr by live SE2 culture. Furthermore a small quantity (23%) of mercury was accumulated in live cell pellets. While no volatilization was caused by dead cells, sorption of mercury was confirmed. The mercuric reductase gene merA was amplified and sequenced. Homology was observed among the amino acid sequences of mercuric reductase enzyme of different organisms from α-Proteobacteria and ascomycota groups.]]> Mon 17 Dec 2018 08:16:10 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33740 Mon 17 Dec 2018 08:16:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:53775 Mon 15 Jan 2024 10:09:33 AEDT ]]>