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P Millner

Publications and source records attributed to P Millner.

8 recordsLinked to original sources
PubMed2003

Removal of heavy metals from a metaliferous water solution by Typha latifolia plants and sewage sludge compost.

Typha latifolia plants, commonly known as cattails, were grown in a mixture of mature sewage sludge compost, commercial compost and perlite (2:1:1 by volume). Four Groups (A, B, C and D) were irrigated (once every two weeks) with a solution containing different concentrations of Cu, Ni, and Zn, where in the fifth (group M) tap water was used. At the end of the 10 weeks experimental period substrate and plants were dried, weighed and analysed for heavy metals. The amounts of all three metals removed from the irrigation solution, were substantial. In the roots and leaves/stems of T. latifolia the mean concentration of Zn reached values of 391.7 and 60.8 mg/kg of dry weight (d.w.), respectively. In the substrate of Group D all three metals recorded their highest mean concentrations of 1156.7 mg/kg d.w. for Cu, 296.7 mg/kg d.w. for Ni and 1231.7 mg/kg d.w. for Zn. Linear correlation analyses suggested that there was a linear relationship between the concentration of metals in the solutions and the concentration of metals in the substrates at the end of the experiment. The percentage removal of the metals in the substrate was large, reaching 100% for Cu and Zn in some groups and almost 96% for Ni in group D. The total amount of metals removed by the plants was considerably smaller than that of the substrate, due mainly to the small biomass development. A single factor ANOVA test (5% level) indicated that the build up in the concentration of metals in the roots and the leaves/stems was due to the use of metaliferous water solution and not from the metals pre-existing in the substrate. The contribution of the plants (both roots and leaves/stems) in the removing ability of the system was less than 1%.

Analysis of Variance↗
PubMed2003

Removal of total suspended solids from wastewater in constructed horizontal flow subsurface wetlands.

Subsurface horizontal flow experimental wetlands (reed beds), were designed and built based on a combination of two design methodologies, that of the WRc and Severn Trent Water plc (1996) and that of the USA, EPA (1988). Four different growing media were used with a combination of top soil, gravel, river sand, and mature sewage sludge compost, to determine the best substrate for total suspended solids (TSS) removal. Eight units were constructed, two for each growing media. One bed for each pair was planted with Typha latifolia plants commonly known as cattails. Primary treated domestic wastewater, was continuously fed to the beds for more than six months. All eight beds performed very well. The best performance was achieved by the gravel reed beds with an almost constant removal rate above 95% and an average effluent concentration of less than 10 mg/L. Soil based beds containing top soil and sand, managed to reach values of removal around 90%. The wetlands containing compost in their substrate, produced an effluent with average concentration of less than 30 mg/L and a percentage removal between 80% and 90%. As expected, there was no significant difference in the performance of planted and unplanted wetlands.

Biodegradation, Environmental↗
PubMed2002

The effect of heavy metals on the total protein concentration of Typha latifolia plants, growing in a substrate containing sewage sludge compost and watered with metaliferus wastewater.

Typha latifolia plants, commonly known as cattails, were grown in a mixture of sewage sludge compost, commercial compost and perlite. Large 6.5 L pots were used with one well developed plant in each pot, divided in five groups. Four groups were irrigated with a solution containing different concentrations of Cd, Cu, Ni, Pb and Zn for a period of 10 weeks, where the fifth was used as a blank. Changes in the concentration of total protein in the leaves/stems were monitored aiming to study the effect of heavy metals from both the substrate and the wastewater on the plants' development and health. At the end of the experiment in the leaves/stems of Typha latifolia the mean concentration of Ni and Zn reached values of 27.50 and 60.83 mg/kg of d.w. respectively. Similar high concentrations were recorded for all five metals. This, however, did not resulted in an inhibition of the plants development and health in three of the four groups as evidenced by the increasing concentrations of the total protein in the leaves' tissue. Only in the fourth group, where the stronger solution was used, some evidence of inhibition occurred after the 8th week. The presence of NO- as part of the metals' salts (growth factor), the short period of the experiment and the natural tolerance of Typha latifolia in heavy metals toxicity could explain such phenomenon.

Environmental Monitoring↗
PubMed2001

Analysis of fungal communities by sole carbon source utilization profiles.

A simple method for characterization of fungal communities in environmental samples was developed. Dilute suspensions of samples in 0.2% agar containing three different antibiotics were pipetted into 96-well plates (Biolog SF-N) containing a diverse collection of 95 different carbon sources. The plates were incubated for 4-12 days at 22 degrees C and the absorbance measured at 650 nm. Canonical variates analysis was then used to analyze the multivariate data. This method allowed fungal communities in rhizosphere soil of corn and soybean to be distinguished according to soil and plant type. Data taken at a single time-point, which varied greatly in total absorbance of the plate, separated rhizosphere samples primarily by soil type. When multiple time-points were combined to keep the total absorbance constant, differences in substrate utilization patterns due to different plant types could be distinguished. The method was also applicable to analysis of phylloplane and compost fungal communities. This method is readily applied to large numbers of samples and should be useful for community analysis in a variety of agricultural and ecological studies.

Carbon↗
PubMed1994

Peptides derived from the auxin binding protein elevate Ca2+ and pH in stomatal guard cells of Vicia faba: a confocal fluorescence ratio imaging study.

Dual-excitation confocal laser scanning microscopy (CLSM) was used to image the pH-indicator, BCECF, iontophoretically microinjected into stomatal guard cells of Vicia faba during challenge with peptides derived from hydrophilic domains of the maize auxin-binding protein. Only the peptide corresponding to the C-terminal end (Pz151-163) caused significant changes in cytosolic pH, stimulating rapid alkalinisation of 0.4 +/- 0.1 pH units. Cytosolic pH was clamped using the permeant weak acid, butyrate, and this treatment buffered the peptide evoked alkalinisation. In concert with the electrical events monitored at the plasma membrane using whole-cell voltage clamp, this provides strong evidence for a role of [H+] as a signal intermediate in the guard cell transduction network. In preliminary experiments using single-wavelength imaging of the calcium-indicator, Fluo-3, Pz151-163 also stimulated rapid, reversible increases in cytosolic calcium, whilst two other peptides tested had no effect.

Calcium↗
PubMed1993

Modulation of K+ channels in Vicia stomatal guard cells by peptide homologs to the auxin-binding protein C terminus.

Transduction of the auxin stimulus in plants is thought to entail binding of the hormone to a soluble auxin-binding protein (ABP) outside the cell and subsequent interaction between this auxin-protein complex and an integral membrane receptor ("docking") protein that couples the signal across the plasma membrane. To explore the structural requirements for ABP function, synthetic peptides were prepared to the amino acid sequences of the predicted surface domains of ABPzm1, the dominant ABP from Zea. Biological function was assayed under voltage clamp, monitoring the ability of the peptides to evoke auxin-related modulations in inward- (IK,in) and outward-rectifying (IK,out) K+ channel activities of Vicia guard cells in the absence of added auxin. Only the peptide corresponding to the C-terminal domain of ABPzm1 was active. The dominant response was an inactivation of IK,in, although the peptide also evoked an activation of IK,out. Inactivation of IK,in was complete within 20-30 s and was fully reversible, was marked by a slowing of voltage-dependent activation and deactivation, and was dependent on peptide concentration (K1/2, 16 +/- 6 microM). Buffering cytoplasmic-free [Ca2+] with EGTA had no effect on IK,in response to the peptide. However, virtually complete and reversible block of the response was achieved when cytoplasmic pH (pHi) was brought under experimental control using the weak acid butyrate. Parallel measurements of pHi using the fluorescent dye 2',7'-bis(2-carboxyethyl-5(6)-carboxyfluorescein (BCECF) and dual-wavelength laser-scanning confocal microscopy demonstrated that the C-terminal peptide evoked rapid and reversible cytoplasmic alkalinizations of 0.4 +/- 0.1 pHi unit and confirmed the antagonism of the pHi response in the presence of butyrate. These, and comparable results with the auxins indole acetic acid and 1-naphthyleneacetic acid, implicate the C-terminal domain of ABPzm1 in auxin-ABP coupling to pHi and an associated intracellular signaling cascade.

Amino Acid Sequence↗
PubMedDate not supplied

The removal of chemical oxygen demand from primary-treated domestic wastewater in subsurface-flow reed beds using different substrates.

Subsurface-flow experimental reed beds were designed and built based on a combination of two design methodologies. Four different growing media were used with a combination of topsoil, gravel, river sand, and mature wastewater biosolids compost to determine the best substrate for chemical oxygen demand removal. Eight units were constructed, two for each material. One bed for each pair was planted with Typha latifolia plants commonly known as cattails. Primary-treated domestic wastewater was continuously fed to the beds for more than 6 months. The best performance was achieved by the gravel reed beds, with an average removal rate higher than 50%. Soil-based beds containing topsoil and sand only managed to attain removals of approximately 10%. The reed beds containing compost in their substrate produced the worst treatment, mainly because of leaching of organic substances from the compost. Primarily as a result of channel flow, all beds showed significant deviation from the designed retention time. There was no significant difference in the performance of planted and unplanted reed beds.

Oxygen↗