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In this study, bacterial removal efficiencies of planted and unplanted subsurface vertical flow constructed wetlands are compared. Indicator organisms such as faecal coliforms (Escherichia coli, total coliforms) and enterococci, and a number of heterotrophic bacteria (heterotrophic plate counts) have been analysed from the influent and effluent of the constructed wetlands as well as at different depths (water and substrate samples). Furthermore dry matter content and total organic carbon (TOC) have been analysed and correlated. The investigated systems show a high removal rate for indicator organisms (a log removal rate of 2.85 for HPC, 4.35 for E. coli, 4.31 for total coliforms and 4.80 for enterococci was observed). In general no significant difference in the removal efficiency of planted and unplanted vertical flow beds could be measured. Only enterococci measured in the substrate samples of the main layer of the filter could a statistically significant difference be observed. [Copyright &y& Elsevier]

The main objective of this work was to study catabolic potential of marine sediment bacteria in aerobic degradation of polychlorinated biphenyls (PCBs). Marine sediment samples were collected at urban areas of the Croatian Adriatic coast, and microcosm enrichment experiments were performed in seawater mineral salts (SMS) medium with the addition of biphenyl as the only carbon source. After two to four subcultures, all enriched mixed cultures demonstrated the capability to use biphenyl, indicating that biphenyl-utilizing bacteria are widespread in coastal marine sediments. PCB-degrading activity of the enrichment cultures as well as that of their biphenyl-utilizing members were further studied in SMS medium with the addition of PCB mixtures containing di-to heptachlorinated congeners. GC–MS analyses of the extracted cultures suggested that, although they differed in PCB-degrading capabilities, all of the enrichment cultures expressed activity toward at least some of the lower chlorinated congeners (di-to tetrachlorobiphenyls). Biphenyl-utilizing bacteria isolated from the most active PCB-degrading mixed cultures showed little taxonomic diversity (six out of seven isolates belonged to the genus Rhodococcus and one to the genus Sphingomonas). All isolated Rhodococcus strains (R. erythropolis and R. ruber) showed substantial PCB-degrading activity, suggesting that these bacteria might play an important role in aerobic PCB degradation in polluted marine sediment. [Copyright &y& Elsevier]

Here we introduce a new model of life–environment interaction, which simulates an evolving microbial community in a ‘Fask’ of liquid with prescribed inputs of nutrients. The flask is seeded with a clonal population of ‘microbes’ that are subject to mutation on genetic loci that determine their nutrient uptake patterns, release patterns, and their effects on, and response to, other environmental variables. In contrast to existing models of life-environment interaction, notably Daisyworld, what benefits the individual organisms is decoupled from their ‘global’ (system-level) effects. A robust property of the model is the emergence of ecosystems that tend toward a state where nutrients are efficiently utilised and differentially recycled, with a correlated increase in total population. Organisms alter the environment as a free ‘by-product’ of their growth, and their growth is constrained by adverse environmental effects. This introduces environmental feedback, which can disrupt the model ecosystems, even though there are no constraints on the conditions to which the organisms can theoretically adapt. ‘Rebel’ organisms can appear that grow rapidly by exploiting an under-utilised resource, but in doing so shift the environment away from the state to which the majority of the community are adapted. The result can be a population crash with loss of recycling, followed by later recovery, or in extreme cases, a total extinction of the system. Numerous runs of these ‘flask’ ecosystems show that tighter environmental constraints on growth make the system more vulnerable to internally generated ecosystem extinction. [ABSTRACT FROM AUTHOR]

Resuspension of benthic phosphorus (P) often constitutes a high percentage of the annual P flux in lowland rivers. To study P entrainment at controlled shear velocity ( u*) sediment from lowland River Spree of slower flowing (0.1–0.3 m s−1) stretch Kossenblatt (KOB) and of faster flowing (0.5–0.7 m s−1) stretch Freienbrink (FRB) was incubated in a microcosm at incrementally enhanced u* (0.34–1.9 cm s−1). Particle and P entrainment rates as well as the number of particle-associated bacteria of fine-grained mud-like KOB sediment were much higher (16.7 g m−2 h−1, 104.9 mg P m−2 h−1, 15.47 106 cells ml−1) than those (4.3 g m−2 h−1, 2.1 mg P m−2 h−1, 3.06 106 cells ml−1) of coarser sandy FRB sediment. The microcosm used so far in marine research is suited to compare riverine resuspension suggesting the lower u* the more particles are deposited and the more P can be retained (KOB ≫ FRB). Conversely, correspondingly more and easier particulate P and bacteria can again be remobilised (KOB ≫ FRB) if u* increases. The general relationship found for u* and the entrainment of particulate P and bacteria as well as their decelerated and selective deposition where bacteria may stay longer in the water implies a temporarily enhanced P bioavailability, turnover and subsequent P transformations. [ABSTRACT FROM AUTHOR]

In order to gain insight into the community structure and the biodegradative potential of bacteria residing in a BTEX-contaminated field site, with benzene as main pollutant, an investigation strategy with a variety of cultivation-independent and -dependent approaches was undertaken. Based on 16S ribosomal DNA sequence analysis, sampling stations in the center of the pollution plume were found to be dominated by a bacterial consortium affiliated with various members of the class of Proteobacteria and Firmicutes, including different sporulating and non-sporulating sulfate-reducing bacteria and members of the genus Geobacter. Non-polluted samples retrieved from outside the plume revealed several phylotypes which were also observed in the centre of the plume. Bacterial sequences retrieved from the fringe of the plume were dominated by several genera of beta Proteobacteria subclass which were not associated with other phylotypes obtained in this study. All sampling stations were tested positive for catechol 2,3-dioxygenase genes, indicating the presence of microorganisms with the genetic potential degrading aromatic compounds via the meta-cleavage pathway. The groundwater system at the down-gradient edge of the plume was characterized, in contrast to all other sampling stations in the center and outside the plume, by high numbers of cultivable bacteria and cultivable aerobic benzene and toluene degraders. These findings are also in accordance with the investigations based on fluorescent in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes, suggesting the presence of an actively benzene degrading bacterial community of beta Proteobacteria at the fringe of the pollution plume. [ABSTRACT FROM AUTHOR]

Zero valent iron (ZVI), the primary reactive material in several permeable reactive barriers, is often oxidized to ferrous or ferric iron, resulting in decreased reactivity with time. Iron reducing bacteria can reconvert the ferric iron to its ferrous form, prolonging the reduction of chlorinated organic contaminants. In this study, the reduction of Fe(II,III) oxide and Fe(III) oxide by a strain of iron reducing bacteria of the group Shewanella alga BrY(S. alga BrY) was observed in both aqueous and solid phases. S. alga BrY preferentially reduced dissolved ferric iron over the solid ferric iron. In the presence of iron oxide the Fe(II) ions reduced by S. alga BrY efficiently reduced trichloroethylene (TCE). On the other hand, Fe(II) produced by S. alga BrY covered the reactive surfaces of ZVI iron filings and inhibited the reduction of TCE by ZVI. The formation of precipitates on the iron oxide or Fe0 surface was confirmed by scanning electron microscopy. The results suggest that iron-reducing bacteria in the oxidized Fe0 barriers can enhance the removal rate of chlorinated organic compounds and influence on the long-term performance of Fe0 reactive barriers. [Copyright &y& Elsevier]

A study was conducted to determine the efficiency and effectiveness of two commercial microbial based bioremediation products compared to indigenous tropical microorganisms in a small-scale trial. The oil and grease content of the samples was monitored as an indication of the levels of petroleum hydrocarbon during the experiment. The indigenous enriched culture generally biodegraded the petroleum hydrocarbon to a greater extent than the commercial products and media controls early in the bioremediation process (0–5 days). However, as time progressed the extents of biodegradation were not significantly different between treatments until late in the bioremediation process (after 18 days). Of the two commercial products, one was more effective, reducing the level of oil and grease by 52.5% over the 3 week study. However, neither commercial product was able to meet the manufacturer’s stated level of 95% removal within three weeks. Commercial microbial-based bioremediation products may be used with some success in tropical environments, however location-specific trials may be required to ensure that the best commercial product is selected. As an alternative, the selective enrichment of indigenous microorganisms may result in similar performance at a reduced cost. [ABSTRACT FROM AUTHOR]

A novel bacterium designated strain B-16 was isolated from the compost leachate of the municipal solid waste (MSW) in a laboratory reactor. This strain was identified as a gram-negative bacterium, Achromobacter xylosoxidans that could grow on bisphenol A (BPA, a representative endocrine disruptor) as a sole carbon source under aerobic condition. BPA-degrading characteristics of strain B-16 were investigated in liquid cultures. The results show that BPA degradation was influenced by several factors (e.g. inoculum size, substrate concentration, temperature and pH, etc). The half-lives, optimum temperature and pH were found to be 0. 58–3. 1d, 35°C and 7. 0, respectively. BPA-degrading activity and cell growth were inhibited at high substrate concentration. Metabolic intermediates detected during the degradation process were identified as p-hydroxybenzaldehyde, p-hydroxybenzoic acid and p-hydroquinone, respectively. Metabolic pathway of BPA degradation was proposed in this study. [Copyright &y& Elsevier]

We demonstrate a two-step process used to increase the hydrogen yield from sucrose and to relieve the pollution threat caused by resultant fatty acids in dark-fermentation. In batch tests of dark-fermentation using microflora, the maximum hydrogen production rate was mL and the maximum hydrogen yield was 3. 67 mol sucrose. The fatty acids produced in dark-fermentation were mainly butyrate and acetate with a small amount of propionate, valerate, n-butyl alcohol, and caproate. Photo-fermentation with Rhodobacter sphaeroides SH2C was then employed to convert these small molecular fatty acids into hydrogen. The total hydrogen yield from sucrose increased from the maximum of 3. 67 mol sucrose in dark-fermentation to 6. 63 mol sucrose by using the two-step process. No butyrate, acetate, propionate, or valerate was detected in the final fermentation effluent after photo-fermentation. Our results suggest that a two-step process of combining dark-and photo-fermentation may increase hydrogen production capacity from biomass and prevent the environmental problems associated with untreated fermentation effluents. [Copyright &y& Elsevier]

Burkholderia sp. C3 was isolated from a polycyclic aromatic hydrocarbon (PAH)-contaminated site in Hilo, Hawaii, USA, and studied for its degradation of phenanthrene as a sole carbon source. The initial 3,4-C dioxygenation was faster than 1,2-C dioxygenation in the first 3-day culture. However, 1-hydroxy-2-naphthoic acid derived from 3,4-C dioxygenation degraded much slower than 2-hydroxy-1-naphthoic acid derived from 1,2-C dioxygenation. Slow degradation of 1-hydroxy-2-naphthoic acid relative to 2-hydroxy-1-naphthoic acid may trigger 1,2-C dioxygenation faster after 3 days of culture. High concentrations of 5,6-and 7,8-benzocoumarins indicated that meta-cleavage was the major degradation mechanism of phenanthrene-1,2-and-3,4-diols. Separate cultures with 2-hydroxy-1-naphthoic acid and 1-hydroxy-2-naphthoic acid showed that the degradation rate of the former to naphthalene-1,2-diol was much faster than that of the latter. The two upper metabolic pathways of phenanthrene are converged into naphthalene-1,2-diol that is further metabolized to 2-carboxycinnamic acid and 2-hydroxybenzalpyruvic acid by ortho-and meta-cleavages, respectively. Transformation of naphthalene-1,2-diol to 2-carboxycinnamic acid by this strain represents the first observation of ortho-cleavage of two rings-PAH-diols by a Gram-negative species. [ABSTRACT FROM AUTHOR]

Contamination of groundwater with the gasoline additive methyl tert-butyl ether (MTBE) is often accompanied by many aromatic components such as benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene (BTEX). In this study, a laboratory-scale biotrickling filter for groundwater treatment inoculated with a microbial consortium degrading MTBE was studied. Individual or mixtures of BTEX compounds were transiently loaded in combination with MTBE. The results indicated that single BTEX compound or BTEX mixtures inhibited MTBE degradation to varying degrees, but none of them completely repressed the metabolic degradation in the biotrickling filter. Tert-butyl alcohol (TBA), a frequent co-contaminant of MTBE had no inhibitory effect on MTBE degradation. The bacterial consortium was stable and showed promising capabilities to remove TBA, ethylbenzene and toluene, and partially degraded benzene and xylenes without significant lag time. The study suggests that it is feasible to deploy a mixed bacterial consortia to degrade MTBE, BTEX and TBA at the same time. [ABSTRACT FROM AUTHOR]

Fenitrothion, a toxic organophosphorus pesticide, can build up the concentration of nitrophenolic compound in soils and hence needs to be removed. Burkholderia sp. FDS-1, a fenitrothion-degrading strain, was used in this work to study factors affecting its growth, and then evaluated for its capacity to degrade fenitrothion in soil microcosms. Minimal salt medium containing 1% (w/v) glucose was found to be a suitable carbon source for inoculum preparation. Various factors, including soil pH, temperature, initial fenitrothion concentration, and inoculum size influenced the degradation of fenitrothion. Microcosm studies performed with varying concentrations (1–200mgkg−1) of fenitrothion-spiked soils showed that strain FDS-1 could effectively degrade fenitrothion in the range of 1–50mgkg−1 soil. The addition of Burkholderia sp. FDS-1 at 2×106 colony forming unitsg−1 soil was found to be suitable for fenitrothion degradation over a temperature range of 20–40°C and at a slight alkaline pH (7. 5). The results indicate that strain FDS-1 has potential for use in bioremediation of fenitrothion and its metabolite-contaminated sites. This is a model study that could be used for decontamination of sites contaminated with other compounds. [Copyright &y& Elsevier]

The depth distribution of planctomycete abundance has been examined in six different sites of the Sphagnum peat bog Bakchar, Tomsk oblast, Russia. In situ hybridization of peat with the fluorescently labeled oligonucleotide probes PLA46 and PLA886, reported to be group-specific for representatives of the phylum Planctomycetes, revealed two distinct population maxima of these bacteria in all of the profiles examined. The first population maximum was detected in the uppermost, oxic layer of the bog profile, while the second maximum was located at a depth of 30 cm below the water table level. The population sizes of planctomycetes in the uppermost layer and at a depth of 30 cm were of the same order of magnitude and comprised 0.5–1.5 × 107 and 0.4−0.7 × 107 cells per g−1 of wet peat, respectively. Only 25–30% of the total number of planctomycete cells in the anoxic layer could be detected if the probe PLA886, whose target specificity is restricted to taxonomically characterized aerobic planctomycetes of the genera Gemmata, Planctomyces, Pirellula, and Isosphaera, was used alone. Other planctomycete cells in this layer were detected only with the probe PLA46, which possesses a much wider scope. This suggests the affiliation of these organisms with a yet undescribed phylogenetic subgroup within the Planctomycetes. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) is emitted from pig manure composting, and the emission correlates with nitrite (NO2-) accumulation in the composting material. In the present study, we added nitrite-oxidizing bacteria (NOB)to inhibit NO2- accumulation and evaluated its effect on N2O emission in a laboratory-scale composting experiment. Mature pig manure compost (MPMC) containing NOB at 106 MPN g-1 WM or cultured MPMC (cul-MPMC) NOB at 1011 MPN g-1 WM was added after the thermophilic phase of composting. The addition of these materials prevented NO2- accumulation, promoting oxidation to nitrate (NO3-), whereas the accumulation of NO2- occurred in the material to which NOB was not added as the result of the delayed growth of indigenous NOB compared with that of ammonia-oxidizing bacteria (AOB). The pattern of NO2- in the material agreed with that of N2O emission; therefore, N2O emission ceased rapidly when NOB was added. Emission rates of N2O were 88.5 (no addition), 17.5 (MPMC addition), and 20.2 (cul-MPMC addition) g N-N2O kg-1 TNinitial, respectively. Improving composition of nitrifying communities for complete nitrification promotion would be useful to establish a composting method with low N2O emission. [ABSTRACT FROM AUTHOR]

The article discusses the experiment conducted using sulfate-reducing bacteria (SRB) to assess the effects of electron donors on the efficiency of in situ precipitation (ISMP) of heavy metal contaminations on groundwater. Earlier experiments were conducted to test the effect of ISMP in treating heavy metal contaminated groundwater using other substances, this study is focused on the effect of electron donors on the SRB as an element for the ISMP treatment. Results show that all carbon sources tested promoted SRB activity, however, the efficiency of the ISMP process decreased. It was concluded that the ISMP process failed in the case of an intentional disruption of substrate supply because the growth of SRB stopped due to the lack of carbon and electron donor.

Two strains of bacteria were isolated from deep-ocean sediments of the South China Sea using enrichment culturing technique and they were identified as Sphingomonas yanoikuyae DOS01 (AY878409) and Variovorax paradoxus T4 (AY878410) based on 16S rRNA gene sequences. S. yanoikuyae DOS01 was only capable of transforming dimethyl terephthalate (DMTP) to monomethyl terephthalate (MMTP) without further degradation while V. paradoxus T4 exhibited ability in mineralizing DMTP as the sole source of carbon and energy. The biochemical pathway of DMTP degradation was through MMTP and terephthalic acid (TA) as major detectable degradation intermediates in the culture media by both microorganisms. V. paradoxus T4 utilized DMTP and MMTP via hydrolysis of diester and monoester in the initial steps in degradation as confirmed by total organic carbon analysis of the culture medium and esterase activity assay of the lysed cells and fraction. The specific hydrolysis activity of esterase induced by DMTP or MMTP showed that greater hydrolysis of p-nitrophenyl acetate by esterase induced by DMTP-grown cells than that induced by MMTP. Results of this research suggest that the cleavage of the two identical carboxylic ester groups of phthalate diester are carried out by highly specific esterases of the same bacteria in the environment. [ABSTRACT FROM AUTHOR]

Experiments on the biodegradation of unusable medicines containing a phenolic hydroxy group by actinobacteria of the genus Rhodococcus were performed. Six species and sixty-four strains were tested. It was found that rhodococci could degrade paracetamol, and some R. ruber strains showed high levels of its degradation. An efficient method for the identification and quantification of paracetamol and the products of its conversion ( p-aminophenol, pyrocatechol, and hydroquinone) immediately in the culture liquid was developed. Conditions for the complete biodegradation of paracetamol dosage forms (pills) were optimized. The experimental results can be applied to the development of biotechnological methods for degrading medicines: faked, rejected, or those that are expired. [ABSTRACT FROM AUTHOR]

No abstract available. [ABSTRACT FROM AUTHOR]

Degradation of dimethyl isophthalate (DMI) and dimethyl phthalate ester (DMPE) was investigated using microorganisms isolated from mangrove sediment of Hong Kong Mai Po Nature Reserve. One enrichment culture was capable of utilizing DMI as the sole source of carbon and energy, but none of the bacteria in the enrichment culture was capable of degrading DMI alone. In co-culture of two bacteria, degradation was observed proceeding through monomethyl isophthalate (MMI) ester and isophthalic acid (IPA) before the aromatic ring opening. Using DMI as the sole carbon and energy source, Klebsiella oxytoca Sc and Methylobacterium mesophilicum Sr degraded DMI through the biochemical cooperation. The initial hydrolytic reaction of the ester bond was by K. oxytoca Sc and the next step of transformation was by M. mesophilicum Sr, and IPA was degraded by both of them. In another investigation, a novel bacterium, strain MPsc, was isolated for degradation of dimethyl phthalate ester (DMPE) also from the mangrove sediment. On the basis of phenotypic, biochemical and 16S rDNA gene sequence analyses, the strain MPsc should be considered as a new bacterium at the genus level (8% differences). This strain, together with a Rhodococcus zopfii isolated from the same mangrove sediment, was able to degrade DMPE aerobically. The consortium consisting of the two species degraded 450 mg/l DMPE within 3 days as the sole source of carbon and energy, but none of the individual species alone was able to transform DMPE. Furthermore, the biochemical degradation pathway proceeded through monomethyl phthalate (MMP), phthalic acid (PA) and then protocatechuate before aromatic ring cleavage. Our results suggest that degradation of complex organic compounds including DMI and DMPE may be carried out by several members of microorganisms working together in the natural environments. [ABSTRACT FROM AUTHOR]

The role of the bacterial ribosome in the cellular response to environmental stress has been widely considered over last decade. Certain ribosomeassociated proteins have been shown to induce conformational changes that lead to the formation of inactive forms of ribosomes that are presumed to be more stable during stationary phase. This was found to aid the survival of bacteria in this phase. Such proteins include ribosome modulation factor (RMF), YfiA and YhbH. Examining the influence of RMF on the survival of E. coli under heat, acid and osmotic stress showed that it was important for bacterial viability under these environmental pressures. However, the mechanism by which this protein exerts its effect has not been fully elucidated. The present work reviews the involvement of ribosomes in determining cell behaviour during stress. It focuses on the action of the ribosome-associated proteins and their role in inactivating ribosomes for preserving their integrity and aiding cell survival under stress. [ABSTRACT FROM AUTHOR]

Bacterial cells have adapted in a variety of ways to resist oxidative stresses and damage in their everyday lives in a predominantly aerobic world. The nearly universal occurrence of resistance mechanisms against oxidative stresses, particularly those due to reactive oxygen species (ROS), suggests that most, if not all, bacteria have to deal with oxidative assaults. A primary source of oxidative stress is aerobic metabolism, which leads to production of ROS such as hydrogen peroxide, superoxide radical, perhydroxyl radical, hydroxyl radical and a variety of other toxic metabolites, including organic peroxides and other organics or inorganics able to transfer electrons to sites of oxidative damage. Anaerobes as well as aerobic and facultative organisms are subject to oxidative stresses, often as a result of their own metabolism of O2 or that of associated facultative organisms. If anaerobes would just ignore oxygen instead of metabolizing it, they would not have to deal with toxic metabolites of their own making. Another major source of oxidative stress comes from the use of oxidative agents in the disinfection-sterilization industry. Notable examples are hypochlorite for water purification and hydrogen peroxide used for industrial sterilization. Antimicrobials such as isoniazide and mitomycin C also act oxidatively to cause damage. In this article, aseptic packaging and processing involving use of hydrogen peroxide for sterilization of packaging materials is reviewed as an example of oxidative stress imposed on bacterial spores and vegetative cells from outside the organisms or the microbial community. The other example considered is related to oral microbiology and infectious disease in which oxidative stress may arise from the metabolism of the oral microbiota or may come from outside through use of oral care products. [ABSTRACT FROM AUTHOR]

There are several unusual features about phage when you first encounter them as a biologist. They are small, but conform to one of a few morphological types. Next their genomes can be composed of DNA or RNA and be single or double stranded. Finally they are numerically more abundant than prokaryotes and a significant proportion of them form an association in their microbial host populations termed lysogeny. The latter findings indicate that they are numerically significant in microbial populations. Since bacterial and phage abundance or lack of it is related in environments, this implies that the phage populations `titrate' their hosts, and more probably the host's physiological status. Microbial populations wax and wane with nutritional inputs and there is a dynamic relationship between phage population sizes and host numbers and physiology. Overlay this with the different phage life cycle strategies, exemplified at the extremes by phage lambda (temperate) and phage T4 (virulent), then it becomes apparent that phage are a component in nutrient cycling in ecology. But their contribution does not stop there. Many are capable of transduction, moving DNA from one cell into another. So they can also aid the evolutionary progress of microbial populations by allowing them to share genes, just as gene exchange via plasmids and transformation does. Our perception of bacteria has been derived from pure culture studies and we are just being able to appreciate how subtle their ecological interactions are. This is no less true of the studies on bacteriophage, which are almost all based on laboratory experimentation, where the hosts are physiologically stressed by growing in `high nutritional and optimum conditions'. The natural environment is naturally discontinuous and life evolved in this. Thus our perceptions of bacteriophage and their life cycle patterns derived from laboratory experimentation may be a little off the mark when we come to understand how they and their hosts interact in the niches available to them. It is worth just considering this as you read the article, as I suspect phage behaviours are more intimately involved in, and moderated by the physiological stresses in the life cycle of bacteria than we currently believe. [ABSTRACT FROM AUTHOR]

Investigates the removal and recovery of copper ions from wastewater by Micrococcus sp. Equilibrium behavior of copper biosorption as described by the Langmuir isotherm model; Role of calcium alginate and polyacrylamide in immobilization of Micrococcus sp. cells; Process that was capable of producing an effluent at low copper concentration, with only a minimum amount of desorbing agent used; Results suggesting ion exchange as one of the dominant mechanisms of metal biosorption for this bacterial strain.

Some physiological characteristics of a phosphate (Pi)-removing bacterium, Microlunatus phosphovorus, are investigated using aerobically grown cells and cells exhibiting excess Pi accumulation (EPA) in order to determine a simplified isolation and identification method for other Pi-removing bacteria. Such a method would save on the amount of sterile equipment needed, and reduce the number of experimental steps and labor time. The EPA activity of the isolate reached a plateau 13 hours into the anaerobic incubation time, but it reached 70% of that level after only 5 hours. The EPA activity of the cells during the stationary growth phase was higher than that during the exponential growth phase. Polyphosphate (polyP) accumulated in the cells was shown to be used as an energy storage material (a phosphagen) under both aerobic and anaerobic conditions. During aerobic starvation, the rate of decrease in the ATP concentration of the suspension of cells that contained polyp was markedly less than that of the suspension of cells without polyP. Therefore, bacterial cells rich in polyP survive longer than bacterial cells lacking polyP. [ABSTRACT FROM AUTHOR]

The article focuses on a research that determines the methods used for calculations of median effect concentration values of chemicals with bioluminescent bacteria, which are primarily developed for pharcological and toxicological sciences. Six different bioluminescent bacteria have been evaluated using a method designed to estimate the effective median concentration. An overnight culture was also made for aerobic growth toxicity using a routine air accessible culture. Results indicate a variation in the sensitivity of toxicity among test organisms because no organism appeared to be uniformly sensitive to all compounds. The findings warrant the need for a variety of tests and organisms when conducting an environmental screen for ecotoxicity.

The article presents a study which determines the characteristics of methylmercury-volatilization bacteria in sediments of Minamata Bay in Japan and the volatilization of mercury compounds by the bacteria. The study used the agar dilution method to determine the minimal inhibitory concentrations (MIC) of mercury chloride and ethylmercury chloride. Results show that the mercury concentrations in Minamata Bay's sediments were 32.4 μg/ml and 23.5 μg/ml.

The article offers information on the risk factors that may lead to fatal outcome in Scrub Typhus, an acute febrile illness induced by the intracellular organism Orientia tsutsugamushi (O. tsutsugamushi). It mentions that the apoptotic changes which occurred in lymphocytes in the regional lymph nodes and spleens may explain immunosurpression in scrub typhus with clinical fatal outcome. It says that bacterial virulence and pathogenicity can also be considered as a risk factor in which the bacterial infection of host cells is due to the interactions between bacterial surface components, complementary host cell receptors, and intracellular matrix molecules. Moreover, the genetic factor of the host is identified to be an important determinants of vulnerability to death from scrub typhus.

Engineering bacteria to clean-up oil spills is rapidly advancing but faces regulatory hurdles and environmental concerns. Here, we develop a new technology to harness indigenous soil microbial communities for bioremediation by flooding local populations with catabolic genes for petroleum hydrocarbon degradation. Overexpressing three enzymes (almA, xylE, p450cam) in Escherichia coli led to degradation of 60–99% of target hydrocarbon substrates. Mating experiments, fluorescence microscopy and TEM revealed indigenous bacteria could obtain these vectors from E. coli through several mechanisms of horizontal gene transfer (HGT), including conjugation and cytoplasmic exchange through nanotubes. Inoculating petroleum-polluted sediments with E. coli carrying the vector pSF-OXB15-p450camfusion showed that the E. coli cells died after five days but a variety of bacteria received and carried the vector for over 60 days after inoculation. Within 60 days, the total petroleum hydrocarbon content of the polluted soil was reduced by 46%. Pilot experiments show that vectors only persist in indigenous populations when under selection pressure, disappearing when this carbon source is removed. This approach to remediation could prime indigenous bacteria for degrading pollutants while providing minimal ecosystem disturbance. [ABSTRACT FROM AUTHOR]

The authors reflect on the antibiotic resistance genes (ARGs) occurrence and diversity. Topics discussed include the bacterial pathogens, the ARGs environmental contamination, and the multidrug-resistant bacteria. Also mentioned are the effects of antibiotic feeding, the factors which supports the ARGs dissemination, and the environment antibiotic resistance.

The article discusses a study on Panda feces that contains bacteria by Ashli Brown and colleagues which provides faster, cost effective, and cleaner way to make biofuels. It says the study can help expand the use of biofuels, cut the foreign oil dependency, and strengthens the importance of wildlife conservation. It mentions the bacteria can break down the plant material lignocellulose which can increase the cellulosic biofuels without relying on food crops such as soybeans, corn, and sugar.

The article offers information on the pilot study related to elimination of bacterial aerosols transmission in the dental clinic. The authors first outline the incidence of bioaerosol-associated infection, risks, and the impact on the usage of air cleaning system (ACS). Bioaerosol atmospheric samples are collected and examined wherein it emphasizes the significant decrease of bacterial aerosol levels with the use of ACS.

The article presents the research findings of microbial degradation of Deepwater Horizon drilling platform oil spill at the Gulf of Mexico. Richard Camilli of Woods Hole Oceanographic Institution, Massachusetts reports that microbial activity level is low while Terry Hazen of Lawrence Berkeley National Laboratory, California confirms the active process. Meanwhile, David Valentine of the University of California studies the carbon isotope C to solve the contradiction of previous observations.

The article discusses an investigation conducted into a salmonella outbreak that occurred in the water supply of Alamosa, Colorado. The investigation was led by the Colorado Department of Public Health and the Environment (CDPHE) and included an initial test for total coliform bacteria followed by an epidemiological survey. The author states that the water supply was not previously chlorinated due to the belief that the aquifer was deep enough to be considered safe from microbial contamination. Quotes are presented from CDPHE chief medical officer Ned Colange concerning how the bacteria incubates in humans and what symptoms it produces. The end result of the investigation was a decision to chlorinate the water supply.

Corrections to the article that was published in the 2007 issue are presented.

An introduction to the journal is presented in which the editor discusses various reports published within the issue including the model system used to describe the interaction of bacteria in the environment, the adaptation of genus Cryptococcus to their human host, and the metabolic and ecological properties of fungi.

The bacterial pathogen Legionella pneumophila responds to environmental changes by differentiation. At least two forms are well described: replicative bacteria are avirulent; in contrast, transmissive bacteria express virulence traits and flagella. Phenotypic analysis, Western blotting, and electron microscopy of mutants of the regulatory genes encoding RpoN, FleQ, FleR, and FliA demonstrated that flagellin expression is strongly repressed and that the mutants are nonflagellated in the transmissive phase. Transcriptome analyses elucidated that RpoN, together with FleQ, enhances transcription of 14 out of 31 flagellar class II genes, which code for the basal body, hook, and regulatory proteins. Unexpectedly, FleQ independent of RpoN enhances the transcription of fliA encoding sigma 28. Expression analysis of a fliA mutant showed that FliA activates three out of the five remaining flagellar class III genes and the flagellar class IV genes. Surprisingly, FleR does not induce but inhibits expression of at least 14 flagellar class III genes on the transcriptional level. Thus, we propose that flagellar class II genes are controlled by FleQ and RpoN, whereas the transcription of the class III gene fliA is controlled in a FleQ-dependent but RpoN-independent manner. However, RpoN and FleR might influence flagellin synthesis on a posttranscriptional level. In contrast to the commonly accepted view that enhancer-binding proteins such as FleQ always interact with RpoN to fullfill their regulatory functions, our results strongly indicate that FleQ regulates gene expression that is RpoN dependent and RpoN independent. Finally, FliA induces expression of flagellar class III and IV genes leading to the complete synthesis of the flagellum. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue, including one by Flores and Herrero on the distinction between vegetative cyanobacterial cells and heterocysts, the interaction of the Escherichia coli (S. coli) virulence factors with the host cell components by Croxen and Finlay, and influence of the interaction within and between bacterial species on their competition in nature by Parsek and colleagues.

The article discusses the various organisms that live in the soil. The author mentions that according to Brian McSpadden Gardener, plant pathologist at the Ohio State University with the Ohio Agricultural Research and Development Center, it would be an advantage to learn and understand how the soil works and soil organisms. Gardener has emphasized the importance of soil organisms, as the living things that move the nutrients in the soil. It also discusses the seven soil organisms responsible for the nutrient circulation of soil, including bacteria, fungi, and protozoa.

The article discusses various reports published within the issue, including one about the interaction of microbes in the environment and another about the salt tolerance of metals.

This article describes a scientific experiment designed by the Agricultural Research Service (ARS) Food Technology and Safety Laboratory in Beltsville, Maryland to test the most effective way of decontaminating household sponges. Dirty sponges were soaked in a chlorine bleach solutions, lemon juice or deionized water while other dirty sponges were placed in a dishwasher with a drying cycle or heated in a microwave for one minute. Both microwave heating and dishwashing with a drying cycle proved effective in killing 99.999% of the microbes, yeasts and molds while other treatments killed significantly less.

This article discusses the use of bacteria for bioremediation of uranium contaminated groundwater on a site adjacent to Oak Ridge National Laboratory in Oak Ridge, Tennessee. The underground liquid uranium waste is the result of the uranium enrichment process in weapons manufacturing and decades of dumping the waste products. Joel Kostka, a Florida State University microbiologist is directing a multidisciplinary team of microbiologists, geologist and geochemists in this five year U.S. Department of Energy project. His team has isolated Geobacteraceae bacteria that turn soluble uranium found in groundwater into an insoluble form. They are also focusing on the best ways to inject a carbon food source consisting of glucose or ethanol. The study is work is described in the February 1, 2007 issue of “Geochimica et Cosmochimica Acta."