Emerging technologies in bioremediation: constraints and opportunities.

Intensive industrialisation, inadequate disposal, large-scale manufacturing activities and leaks of organic compounds have resulted in long-term persistent sources of contamination of soil and groundwater. This is a major environmental, policy and health issue because of adverse effects of contaminants on humans and ecosystems. Current technologies for remediation of contaminated sites include chemical and physical remediation, incineration and bioremediation.

Potential applications of bioprocess technology in petroleum industry.

Petroleum refining is traditionally based on the use of physicochemical processes such as distillation and chemical catalysis that operate under high temperatures and pressures conditions, which are energy intensive and costly. Biotechnology has become an important tool for providing new approaches in petroleum industry during oil production, refining and processing as well as managing environmentally safe pollutant remediation and disposal practices. Earlier biotechnology applications in the petroleum industry were limited to microbial enhanced oil recovery, applications of bioremediation to contaminated marine shorelines, soils and sludges.

Plant-microbe interactions: novel applications for exploitation in multipurpose remediation technologies.

Soil remediation that revitalizes degraded or contaminated land while simultaneously contributing to biomass biofuel production and carbon sequestration is an attractive strategy to meet the food and energy requirements of the burgeoning world population. As a result, plant-based remediation approaches have been gaining in popularity. The drawbacks of phytoremediation, particularly those associated with low productivity and limitations to the use of contaminant-containing biomass, could be addressed through novel biotechnological approaches that harness recent advances in our understanding of chemical interactions between plants and microorganisms in the rhizosphere and within plant tissues.

Safety and immunogenicity of Brucella abortus strain RB51 vaccine in cross bred cattle calves in India.

Safety and immunogenicity of Brucella abortus RB51 vaccine has been evaluated in an organised dairy farm in India. All the cattle (r = 29) vaccinated with strain RB51 'responded' to the vaccine as demonstrated by iELISA using acetone killed strain RB51 antigen. The percentage responders at day 35, 60 and 90 post vaccination were 100%, 95% and 20%, respectively.

Involvement of NADPH oxidase and glutathione in zinc-induced dopaminergic neurodegeneration in rats: similarity with paraquat neurotoxicity.

An association between excessive zinc (Zn) accumulation in brain and incidences of Parkinson's disease (PD) has been shown in several epidemiological and experimental investigations. The involvement of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and glutathione (GSH) in the pathogenesis of PD has also been proposed in a few studies. Despite the implicated role of oxidative stress in PD, the entire mechanism of Zn-induced dopaminergic neurodegeneration has not yet been clearly understood.

Microbial diversity affects self-organization of the soil-microbe system with consequences for function.

Soils are complex ecosystems and the pore-scale physical structure regulates key processes that support terrestrial life. These include maintaining an appropriate mixture of air and water in soil, nutrient cycling and carbon sequestration. There is evidence that this structure is not random, although the organizing mechanism is not known.

Antibiotic resistance gene abundances correlate with metal and geochemical conditions in archived Scottish soils.

The vast majority of antibiotic resistant genes (ARG) acquired by human pathogens have originated from the natural environment. Therefore, understanding factors that influence intrinsic levels of ARG in the environment could be epidemiologically significant. The selection for metal resistance often promotes AR in exposed organisms; however, the relationship between metal levels in nature and the intrinsic presence of ARG has not been fully assessed.

Oxidative stress in zinc-induced dopaminergic neurodegeneration: implications of superoxide dismutase and heme oxygenase-1.

The study was undertaken to investigate the effect of zinc (Zn) on glutathione S-transferase (GST) and superoxide dismutases (SOD) activities and on the expressions of cytosolic Cu, Zn-SOD (SOD1), mitochondrial Mn-SOD (SOD2), γ-glutamyl cysteine synthetase (γ-GCS) and heme oxygenase-1 (HO-1) in the nigrostriatal tissue of rats. Additionally, Zn-induced alterations in the neurobehavioral parameters, lipid peroxidation (LPO), striatal dopamine and its metabolites and tyrosine hydroxylase (TH) protein expression were measured to assess their correlations with the oxidative stress. Zn exposure reduced the locomotor activity, rotarod performance, striatal dopamine and its metabolites and TH protein expression.

Response of methanotrophic communities to afforestation and reforestation in New Zealand.

Methanotrophs use methane (CH(4)) as a carbon source. They are particularly active in temperate forest soils. However, the rate of change of CH(4) oxidation in soil with afforestation or reforestation is poorly understood.

Links between ammonia oxidizer community structure, abundance, and nitrification potential in acidic soils.

Ammonia oxidation is the first and rate-limiting step of nitrification and is performed by both ammonia-oxidizing archaea (AOA) and bacteria (AOB). However, the environmental drivers controlling the abundance, composition, and activity of AOA and AOB communities are not well characterized, and the relative importance of these two groups in soil nitrification is still debated. Chinese tea orchard soils provide an excellent system for investigating the long-term effects of low pH and nitrogen fertilization strategies.

Microorganisms and climate change: terrestrial feedbacks and mitigation options.

Microbial processes have a central role in the global fluxes of the key biogenic greenhouse gases (carbon dioxide, methane and nitrous oxide) and are likely to respond rapidly to climate change. Whether changes in microbial processes lead to a net positive or negative feedback for greenhouse gas emissions is unclear. To improve the prediction of climate models, it is important to understand the mechanisms by which microorganisms regulate terrestrial greenhouse gas flux.

Maneb and paraquat-induced modulation of toxicant responsive genes in the rat liver: comparison with polymorphonuclear leukocytes.

Experimental studies have shown that toxicant responsive genes, cytochrome P450s (CYPs) and glutathione S-transferases (GSTs) play a critical role in pesticide-induced toxicity. CYPs play pro-oxidant role and GSTs offer protection in maneb (MB) and paraquat (PQ)-induced brain and lung toxicities. The present study aimed to investigate the effect of repeated exposures of MB and/or PQ on lipid peroxidation (LPO), glutathione content (GSH) and toxicant responsive genes, i.

Drug discovery from uncultivable microorganisms.

Environmental microbes are a major source of drug discovery, and several microbial products (antibiotics, anti-tumour products, immunosuppressants and others) are used routinely for human therapies. Most of these products were obtained from cultivable (<1%) environmental microbes, and this means that the vast majority of microbes were not targeted for drug discovery. With the advent of new and emerging technologies, we are poised to harvest novel drugs from the so-called 'uncultivable' microbes.

Effect of zinc and paraquat co-exposure on neurodegeneration: Modulation of oxidative stress and expression of metallothioneins, toxicant responsive and transporter genes in rats.

Oxidative stress is implicated in Parkinson's disease (PD). Metallothioneins (MT), cytochrome P450 IIE1 (CYP2E1) and glutathione S-transferases alpha4-4 (GSTA4-4) are involved in oxidative stress-mediated damage. Altered dopamine transporter (DAT) and vesicular monoamine transporter-2 (VMAT-2) are also documented in PD.

Exploring microbial diversity for biotechnology: the way forward.

Environmental microbes are immensely diverse and have numerous metabolic activities and products that could have industrial applications. However, >99% of environmental microbes cannot be cultured under current laboratory conditions, leaving their potential largely untapped. Metagenomic approaches have been used successfully in recent years to obtain novel microbial products from uncultured microorganisms.

Application of fingerprinting molecular methods in bioremediation studies.

Bioremediation has been identified as a beneficial and effective strategy for the removal of recalcitrant environmental contaminants. Bioaugmentation of polluted environments with exogenous degrading microorganisms constitutes a major strategy of bioremediation. However, the ecological role of these strains and their impact on the endogenous microbial community of the micro-ecosystems where they are released should be known.

Effect of continuous olive mill wastewater applications, in the presence and absence of nitrogen fertilization, on the structure of rhizosphere-soil fungal communities.

Olive mill wastewater (OMW) is rich in potentially toxic organics precluding its disposal into water receptors. However, land application of diluted OMW may result in safe disposal and fertilization. In order to investigate the effects of OMW on the structure of soil fungal groups, OMW was applied daily to pepper plants growing in a loamy sand and a sandy loam at two doses for a period of 3 months (total OMW equivalents 900 and 1800 m(3) ha(-1)).

Activity and structure of methanotrophic communities in landfill cover soils.

The composition of the methanotrophic community in soil covers on five landfills in Northern and Eastern Germany was investigated by means of diagnostic microarray and terminal restriction fragment length polymorphism (T-RFLP), both targeting the pmoA gene of methanotrophs. Physical and chemical properties of the 15 sampled soil profiles varied greatly, thus providing for very different environmental conditions. The potential methane oxidation activity, assessed using undisturbed soil cores, varied between 0.

Isolation and identification of novel microcystin-degrading bacteria.

Of 31 freshwater bacterial isolates screened using the Biolog MT2 assay to determine their metabolism of the microcystin LR, 10 were positive. Phylogenetic analysis (16S rRNA) identified them as Arthrobacter spp., Brevibacterium sp.

Response of fungal, bacterial and ureolytic communities to synthetic sheep urine deposition in a grassland soil.

In grazed pastures, soil pH is raised in urine patches, causing dissolution of organic carbon and increased ammonium and nitrate concentrations, with potential effects on the structure and functioning of soil microbial communities. Here we examined the effects of synthetic sheep urine (SU) in a field study on dominant soil bacterial and fungal communities associated with bulk soil and plant roots (rhizoplane), using culture-independent methods and a new approach to investigate the ureolytic community. A differential response of bacteria and fungal communities to SU treatment was observed.

Organophosphorus-degrading bacteria: ecology and industrial applications.

The first organophosphorus (OP) compound-degrading bacterial strain was isolated from a paddy field in the Philippines in 1973. Since then, several phylogenetically distinct bacteria that can degrade OP by co-metabolism, or use OPs as a source of carbon, phosphorus or nitrogen, have been isolated from different parts of the world. There is huge potential for industrial applications of OP-degrading bacteria.

Multiple profiling of soil microbial communities identifies potential genetic markers of metal-enriched sewage sludge.

The long-term impacts of Cu- and Zn-rich sewage sludge additions on the structure of the microbial community in a field under pasture were investigated using a combination of multiplex-terminal restriction fragment length polymorphism (M-TRFLP) and T-RFLP profiling approaches. Changes in the community structure of bacteria, fungi, archaea and actinobacteria were observed in soils that had previously received Cu- (50-200 mg kg(-1) soil) and Zn- (150-450 mg kg(-1) soil) rich sewage sludge additions. Changes in the structure of all microbial groups measured were observed at Cu and Zn rates below the current EU guidelines (135 mg kg(-1) Cu and 300 mg kg(-1) Zn).