Biomass relationship to growth and phosphate uptake ofPseudomonas fluorescens,Escherichia coli andAcinetobacter radioresistens in mixed liquor medium

The ability ofPseudomonas fluorescens, Escherichia coli andAcinetobacter radioresistenns to remove phosphate during growth was related to the initial biomass as well as to growth stages and bacterial species. Phosphate was removed by these bacteria under favourable conditions as well as under unfavourable conditions of growth. Experiments showed a relationship between a high initial cell density and phosphate uptake. More phosphate was released than removed when low initial cell densities (10²–10⁵ cells ml^–1) were used. At a high initial biomass concentration (10⁸ cells ml^–1), phosphate was removed during the lag phase and during logarthmic growth byP. fluorescens. Escherichia coli. at high initial biomass concentrations (10⁷ cells ml^–1), accumulated most of the phosphate during the first hour of the lag phase and/or during logarithmic growth and in some cases removed a small quantily of phosphate during the stationary growth phase.Acinetobacter radioresistens, at high initial cell densities (10⁶, 10⁷ cells ml^–1) removed most of phosphate during the first hour of the lag phase and some phosphate during the stationary growth phase.Pseudomonas fluorescens removed phosphate more thanA. radioresistens andE. coli with specific average ranges from 3.00–28.50 mg L^–1 compared to average ranges of 4.92–17.14 mg L^–1 forA. radioresistens and to average ranges of 0.50–8.50 mg L^–1 forE. coli.     

Inertial motion capture in conjunction with an artificial neural network can differentiate the gait patterns of hemiparetic stroke patients compared with able-bodied counterparts

Clinical gait analysis has proven to reduce uncertainties in selecting the appropriate quantity and type of treatment for patients with neuromuscular disorders. However, gait analysis as a clinical tool is under-utilised due to the limitations and cost of acquiring and managing data. To overcome these obstacles, inertial motion capture (IMC) recently emerged to counter the limitations attributed to other methods. This paper investigates the use of IMC for training and testing a back-propagation artificial neural network (ANN) for the purpose of distinguishing between hemiparetic stroke and able-bodied ambulation. Routine gait analysis was performed on 30 able-bodied control subjects and 28 hemiparetic stroke patients using an IMC system. An ANN was optimised to classify the two groups, achieving a repeatable network accuracy of 99.4%. It is concluded that an IMC system and appropriate computer methods may be useful for the planning and monitoring of gait rehabilitation therapy of stroke victims.     

Using independent nest survey data to validate changes in reporting rates of Martial Eagles between the Southern African Bird Atlas Project 1 and 2

Repeat monitoring is vital to measure biodiversity change. However, monitoring protocols may change, as survey techniques improve or different questions are asked. Such modifications may cause difficulties when examining changes in wildlife populations. The Southern African Bird Atlas Project (SABAP) 1 and 2 are repeat national bird surveys undertaken 20 years apart. These surveys therefore offer unrivalled potential to examine bird population changes in an African context. However, changes in protocols, both spatially and temporally, between the two surveys have raised concerns over using these data to infer population changes. In this study we use independ- ent nest survey data to test whether changes in reporting rates of Martial Eagles in the Kalahari Gemsbok National Park between the two SABAP surveys were reflected in real change in numbers of nesting pairs. From 11 quarter degree squares (QDS), covering c. 8 000 km2, both SABAP and nest surveys suggested a near identical 44% decline. Levels of agreement were weaker at the individual QDS scale, although in 67% of cases the direction of change was the same using both surveys. These results suggest that comparisons in the reporting rates between SABAP 1 and SABAP 2 accurately reflect changes in the breeding population size of this species.     

Bioremediation of petroleum hydrocarbons through landfarming: Are simplicity and cost-effectiveness the only advantages?

The biological removal of petroleum products using landfarming has been applied commercially in large scale with relative success. The technology has been widely used due to its simplicity and cost-effectiveness. However, together with these advantages, there are physical, chemical and biological aspects of the technology that can hamper the remediation process. The dominant pollutant removal mechanisms involved in landfarming are volatilisation of low molecular weight volatile compounds during the early days of contamination or treatment, biodegradation and adsorption. However, volatilisation, leaching of the petroleum products and the remaining recalcitrant hydrocarbon residues present both health and environmental challenges to the rehabilitation practitioners when designing the landfarming technology. Bioaugmentation and biostimulation are promising bioremediation approaches involving landfarming. However, due to the inherent problems related to bioaugmentation such as poor survival of augmented strains, biostimulation should be preferred in contaminated sites with indigenous pollutant-degrading bacteria. Although simplicity and cost-effectiveness are the major advantages for using landfarming, other factors generally regarded as disadvantageous to implementing the technology can be addressed. These includes requirements for large land area for treatment, availability of the pollutant degrading bacteria, effectiveness of the technology at high constituent concentration (more than 50,000 ppm), improved concentration reductions in cases requiring more than 95% of pollution reduction and the flexibility of the technology in integrating the removal of petroleum hydrocarbons with other contaminants that may occur with the petroleum products.     

Effect of the soil yeast <Emphasis Type="Italic">Cryptococcus laurentii</Emphasis> on the photosynthetic water and nutrient-use efficiency and respiratory carbon costs of a Mediterranean sclerophyll, <Emphasis Type="Italic">Agathosma betulina</Emphasis> (Berg.) Pillans

Nothing is known about the effect of soil yeasts on the photosynthetic resource-use and carbon dynamics of plants. Here, we determined the effect of a plant growth-promoting isolate of Cryptococcus laurentii on the photosynthetic water and nutrient-use efficiencies, as well as the carbon economy of a Mediterranean sclerophyll, Agathosma betulina, grown under axenic conditions. The data showed that the higher photosynthetic water-use efficiency in yeast-inoculated plants was a consequence of higher maximum rates of CO₂ assimilation, which was not related to foliar N and P content. We propose that photosynthetic stimulation in yeast-inoculated plants was a result of the increased demand for photosynthates of the yeast-root symbiosis.     

Iron ore weathering potentials of ectomycorrhizal plants

Plants in association with soil microorganisms play an important role in mineral weathering. Studies have shown that plants in symbiosis with ectomycorrhizal (ECM) fungi have the potential to increase the uptake of mineral-derived nutrients. However, it is usually difficult to study many of the different factors that influence ectomycorrhizal weathering in a single experiment. In the present study, we carried out a pot experiment where Pinus patula seedlings were grown with or without ECM fungi in the presence of iron ore minerals. The ECM fungi used included Pisolithus tinctorius, Paxillus involutus, Laccaria bicolor and Suillus tomentosus. After 24?weeks, harvesting of the plants was carried out. The concentration of organic acids released into the soil, as well as potassium and phosphorus released from the iron ore were measured. The results suggest that different roles of ectomycorrhizal fungi in mineral weathering such as nutrient absorption and transfer, improving the health of plants and ensuring nutrient circulation in the ecosystem, are species specific, and both mycorrhizal roots and non-mycorrhizal roots can participate in the weathering process of iron ore minerals.     

Inertial motion capture in conjunction with an artificial neural network can differentiate the gait patterns of hemiparetic stroke patients compared with able-bodied counterparts

Clinical gait analysis has proven to reduce uncertainties in selecting the appropriate quantity and type of treatment for patients with neuromuscular disorders. However, gait analysis as a clinical tool is under-utilised due to the limitations and cost of acquiring and managing data. To overcome these obstacles, inertial motion capture (IMC) recently emerged to counter the limitations attributed to other methods. This paper investigates the use of IMC for training and testing a back-propagation artificial neural network (ANN) for the purpose of distinguishing between hemiparetic stroke and able-bodied ambulation. Routine gait analysis was performed on 30 able-bodied control subjects and 28 hemiparetic stroke patients using an IMC system. An ANN was optimised to classify the two groups, achieving a repeatable network accuracy of 99.4%. It is concluded that an IMC system and appropriate computer methods may be useful for the planning and monitoring of gait rehabilitation therapy of stroke victims.     

A novel Fomitiporia species associated with esca on grapevine in South Africa

Esca disease of grapevine is a complex trunk disease consisting of several symptoms, one of which, white rot, has been found to be caused by various basidiomycetes within the order Hymenochaetales. During recent surveys of esca-related pathogens in South African vineyards, several unidentified basidiomycetes were isolated from white rot occurring in diseased vines. A new Fomitiporia species, F. capensis, is described based on fruit body morphology and combined internal transcribed spacer (ITS) and large-subunit (LSU) phylogeny, where it forms a clearly delineated and well-supported clade. Morphologically, F. capensis is similar to F. punctata in that both species essentially lack setae. Fomitiporia capensis, F. punctata and F. aethiopica produce similarly sized basidiospores but differ in terms of host range, pore size and, possibly, fruit body shape. Phylogenetically, F. capensis appears to be related to F. tenuis, though morphologically, the species differ significantly in that F. tenuis has smaller pores and smaller basidiospores. Fomitiporia capensis was found to occur widely as vegetative mycelium throughout the Western Cape Province, though fruit bodies were scarce in comparison. A vineyard with fruit bodies was also found in Limpopo in the north east of the country. Fruit bodies were found growing on the underside of the cordon of living vines displaying external symptoms typically associated with esca, or general decline and dieback symptoms together with internal white rot.     

Fatal attraction: vegetation responses to nutrient inputs attract herbivores to infectious anthrax carcass sites

Parasites can shape the foraging behaviour of their hosts through cues indicating risk of infection. When cues for risk co-occur with desired traits such as forage quality, individuals face a trade-off between nutrient acquisition and parasite exposure. We evaluated how this trade-off may influence disease transmission in a 3-year experimental study of anthrax in a guild of mammalian herbivores in Etosha National Park, Namibia. At plains zebra (Equus quagga) carcass sites we assessed (i) carcass nutrient effects on soils and grasses, (ii) concentrations of Bacillus anthracis (BA) on grasses and in soils, and (iii) herbivore grazing behaviour, compared with control sites, using motion-sensing camera traps. We found that carcass-mediated nutrient pulses improved soil and vegetation, and that BA is found on grasses up to 2 years after death. Host foraging responses to carcass sites shifted from avoidance to attraction, and ultimately to no preference, with the strength and duration of these behavioural responses varying among herbivore species. Our results demonstrate that animal carcasses alter the environment and attract grazing hosts to parasite aggregations. This attraction may enhance transmission rates, suggesting that hosts are limited in their ability to trade off nutrient intake with parasite avoidance when relying on indirect cues.