Microbial communities involved in the bioremediation of an aged recalcitrant hydrocarbon polluted soil by using organic amendments

An 8-month field bioremediation experiment using fresh (FS) and composted (CS) sewage sludge and unamended soil (US) was carried out on an aged hydrocarbon contaminated semi-arid soil. FS treatments led to the highest percentage of hydrocarbon degradation (46%) and the highest bacterial and fungal population. Denaturing gradient gel electrophoresis analysis demonstrated differences in bacterial and fungal community structure of treated compared to uncontaminated soil (control). Time of sampling accounted for most of the differences than type of treatment. The principal phyla observed in bioremediation treatments were Actinobacteria and Ascomycota. Results pointed to the addition of organic amendments, particularly sewage sludge, as an useful strategy for improving the effectiveness of landfarming biodegradation processes in hydrocarbon polluted soils.

Utilisation of citrus compost-based growing media amended with Trichodermaharzianum T-78 in Cucumismelo L. seedling production

Two citrus composts (C1: composed of 40% citrus wastes, 20% sludge obtained from a citrus industry waste-water treatment facility and 40% green residues; C2: composed of 60% citrus wastes and 40% green residues, and no sludge) and their water extracts amended with Trichodermaharzianum T-78 (T. harzianum T-78) were assayed in order to verify if these composts could act as a partial substitute for peat-based growing media as well as enhance suppressiveness against Fusarium wilt in the production of melon (Cucumismelo L.) seedlings at greenhouse nurseries. Over a 43-day growth cycle of melon seedlings, measurements were taken of the nutriactive effect (the capability of a substrate to express additional and/or synergistic nutritional and biostimulating effects), the pathogen incidence (percentage of fresh weight loss of melon plants grown on treatments infected with Fusariumoxysporum with respect to the same treatment without inoculation of the phytopathogen) and the trend of the T.harzianum T-78 population. A nutriactive effect was observed in the tested citrus compost-based growing media (96% and 112% plant weight increase with respect to peat for C1Th and C2Th, respectively). Pathogen incidence was significantly lower in C2Th than peat (12% compared to 33%), while no difference was observed in C1Th. The T.harzianum T-78 population showed a significant decrease at the first sampling time compared to the initial quantity (from 10(6) to 10(5)CFUg(-1)), but later recovered over time. These results demonstrate that the combination of citrus compost and T.harzianum T-78 can be a viable alternative to peat and can minimise the application of chemicals necessary to control Fusarium wilt in greenhouse nurseries for melon seedling production.

Citrus compost and its water extract for cultivation of melon plants in greenhouse nurseries. Evaluation of nutriactive and biocontrol effects

Two different types of citrus composts, and their water extracts, were tested with regard to their utilisations as partial substitutes for peat in growing media for melon seedlings in greenhouse nurseries. Both compost showed higher plant growth than peat. Compost composed by citrus waste and green residue (C2) showed greater plant growth than compost obtained from the same organic matrices mentioned above further the addition of sludge obtained from citrus industry (C1). Compost C2 showed a greater auxinic effect than C1 and it was the only one that showed cytokinic effect. Both composts also demonstrated a biocontrol effect against Fusarium oxysporum for melon plants: the effects were also higher in C2 than in C1. Higher number of isolated fungi was active against F. oxysporum in compost C2, than compost C1. No different bacterial biocontrol efficacy was observed between both composts. The water extracts of both composts gave lower plant yields than their solid matrices, their relative effects being similar to those of the solid composts (C2 extract gave higher plant yields than the extract from C1). The biocontrol effects of compost water extracts followed the same trend.

A full-scale study of treatment of pig slurry by composting: kinetic changes in chemical and microbial properties

Since the indiscriminate disposal of pig slurry can cause not only air pollution and bad odours but also nutrient pollution of ground waters and superficial waters, composting is sometimes used as one environmentally acceptable method for recycling pig manure. The aim of this study was to evaluate the effect of composting pig slurry on its sanitation (evaluated by ecotoxicity assays and pathogen content determination), as well as to determine the effect of a carbon-rich bulking agent (wood shavings, WS) and the starting C/N ratio on the changes undergone by different chemical (volatile organic matter, C and N fractions) and microbiological (microbial biomass C, ATP, dehydrogenase activity, urease, protease, phosphatase, and beta-glucosidase activities) parameters during composting. Pig slurry mixed with bulking agent (P+WS) and the solid faction separated from it, both with (PSF+WS) and without bulking agent (PSF), were composted for 13 weeks. Samples for analysis were taken from composting piles at the start of the process and at 3, 6, 9, and 13 weeks after the beginning of composting. The total organic carbon, water soluble C and ammonium content decreased with composting, while Kjeldahl N and nitrate content increased. The nitrification process in the PSF+WS pile was more intense than in the PSF or P+WS composting piles. The pathogen content decreased with composting, as did phytotoxic compounds, while the germination index increased with compost age. Piles with bulking agent showed higher values of basal respiration, microbial biomass carbon, ATP and hydrolase activities during the composting process than piles without bulking agent.

Biopesticide effect of green compost against fusarium wilt on melon plants

AIMS

The biopesticide effect of four green composts against fusarium wilt in melon plants and the effect of soil quality in soils amended with composts were assayed.

METHODS AND RESULTS

The composts consisted of pruning wastes, with or without addition of coffee wastes (3/1 and 4/1, dry wt/dry wt) or urea (1000/1, dry wt/dry wt). In vitro experiments suggested the biopesticide effect of the composts against Fusarium oxysporum, while only the compost of pine bark and urea (1000/1dry wt/dry wt) had an abiotic effect. Melon plant growth with composts and F. oxysporum was one to four times greater than in the non-amended soil, although there was no significant decrease in the level of the F. oxysporum in the soil. The addition of composts to the soil also improved its biological quality, as assessed by microbiological and biochemical parameters: ATP and hydrolases involved in the P (phosphatase), C (beta-glucosidase) and N (urease) cycles.

CONCLUSIONS

Green composts had greater beneficial characteristics, improved plant growth and controlled fusarium wilt in melon plants. These composts improve the soil quality of semi-arid agricultural soils.

SIGNIFICANCE AND IMPACT OF THE STUDY

Biotic and abiotic factors from composts have been tested as responsible of their biopesticide activity against fusarium wilt.

Tuberculosis screening among immigrants holding a hunger strike in churches

SETTING

In January 2001, approximately 600 immigrants held a sit-down and hunger strike in several churches in Barcelona to force the Spanish government to comply with demands to regulate their immigration status. Following the diagnosis of a case of smear-positive pulmonary tuberculosis (TB) in one of the immigrants, we performed a large contact investigation.

OBJECTIVES

To describe contact investigation procedures used in this setting and to evaluate contact investigation results.

METHODS

Demographic variables were collected, and tuberculin skin tests (TST) and chest radiograph examinations were performed. Odds ratios (OR) with 95% confidence intervals (CI) were calculated and logistic regression was used for multivariate analyses.

RESULTS

A total of 541 TSTs were performed. Of these, 86% were read and 40.5% yielded a positive reaction with an induration >14 mm. In a multivariate analysis, the risk of presenting a TST induration >14 mm was found to be three times higher among those aged >35 years compared to those <24 years (OR 3.40; 95%CI 1.76-6.59), and for immigrants from Bangladesh (OR 3.14; 95%CI 1.16-6.10) and Pakistan (OR 2.04; 95%CI 1.11-3.73) compared to those from India. A total of 314 chest radiographs examinations were performed and three additional cases of TB were identified, yielding a TB prevalence of 0.7%.

CONCLUSIONS

By focusing efforts and conducting targeted TB screening in this high-risk population, it was possible to complete the intervention in only 3 days. A high prevalence of TB infection and TB disease was found.

Alternative splicing generates a novel non-secretable resistin isoform in Wistar rats1

Resistin is a secreted adipose tissue hormone that belongs to the resistin-like molecule family. We report here a new alternatively spliced isoform of the rat resistin gene, named S-resistin (short resistin), detected in adipose tissue by reverse transcription-polymerase chain reaction (RT-PCR). A comparison of this cDNA variant and genomic sequences indicates the lack of the second exon containing the secretory consensus signal. Both cDNAs, resistin and S-resistin, were carboxy-tagged with FLAG epitope and transiently expressed in cultured cell lines. While the resistin-FLAG construct gives the expected pattern for a secretion protein, the S-resistin-FLAG construct yielded a predominant nuclear staining. These results indicate that this splicing event regulates the fate and probably the function of the mature protein.

Bioremediation of soil degraded by sewage sludge: effects on soil properties and erosion losses

Soils in the Mediterranean area are very prone to erosion due to the loss of organic matter and the consequent lack of protective vegetation. In this experiment a Mediterranean degraded soil with a 15% slope was amended at a rate of 250 t ha(-1) wet weight with sewage sludge and with a mixture of sewage sludge and barley straw (70% carbon from sewage sludge and 30% from the straw) in order to study their influence on soil structure recovery and hence the soils's resistance to erosion processes. Both types of organic amendment led to an improvement in several soil properties (physical, biological, and microbiological) as a result of the spontaneous growth plant covering that became evident three months after amendment. This vegetation remained throughout the two years of the experiment and prevented the water erosion processes that normally precede soil degradation. Amendment by sewage sludge alone reduced soil loss by 80% compared with the control soil, while the mixture that included both sewage sludge and barley straw reduced losses by 84%, both reducing runoff by 57%. The amended soils showed increases in the percentage of stable aggregates, the levels of the total and water-soluble C fractions, microbial biomass C, basal respiration, and the activity of the different enzymes involved in the biogeochemical cycles of C, N, and P. The results confirm the usefulness of sewage sludge as an organic amendment for recovering damaged soils.

Two stage thermophilic anaerobic-aerobic mineralization-stabilization of excess activated sludge

At the National Institute of Chemistry, Ljubljana, Slovenia, new procedure for excess activated sludge was developed and patented. The main principle of the sludge mineralization is two-step process--the first is anaerobic, and the second step is aerobic. In the first step maximal biogas production is acquired in the second step at smaller VSS the optimal VSS and COD is achieved. Anaerobic, aerobic, and combined sludge mineralization was studied. The next combinations of different successive anaerobic and aerobic mineralization have been studied: 3 + 3 (3 days of anaerobic + 3 days of aerobic digestion), 3 + 6, 5 + 5, 3 + 12, and 10 + 10 days, respectively. The best combination considering biogas production, VSS and COD reduction have been gained for the combination of 3 + 6 days, and 3 + 12 days. At 3 + 6 days digestion about 49% of VSS, and about 51% of COD reduction was gained, at 3 + 12 days about 62% of VSS, and about 57% of COD reduction was achieved. For the optimal system operation, economics, biogas production, and necessary VSS and COD reduction have to be considered.

1 Patterning the limb before and after SHH

The Summer Meeting of the Anatomical Society of Great Britain and Ireland was held at the University of Dundee, from 23rd to 25th July 2002. It included a symposium on 'How to make a hand'. The following are abstracts of communications and posters presented at the meeting.

Ageing increases SOCS-3 expression in rat hypothalamus: effects of food restriction

Aged Wistar rats are characterized by leptin and insulin resistance. The expression of SOCS-3 in hypothalamus increases with ageing. Food restriction during 3 months decreases obesity Lee index in aged rats with respect to their ad libitum aged-mates and brings serum leptin concentrations to values close to those of young rats. Food restriction partially reverts the increases in SOCS-3 mRNA levels associated with ageing. These results suggest that SOCS-3 may be a mediator of hypothalamic leptin resistance in the aged Wistar rat and that the hyperleptinemia associated with ageing is, at least in part, responsible for the increase of SOCS-3 expression in hypothalamus.

Long-term food restriction prevents ageing-associated central leptin resistance in wistar rats

AIMS/HYPOTHESIS

Ageing is associated with insulin and leptin resistance in mammals. These alterations might be caused by the increased adiposity associated with ageing, by ageing alone or both. We studied whether leptin resistance occurs at the central level in the Wistar rat and we aimed to discriminate between the effects of ageing from those of the increased adiposity associated with ageing.

METHODS

Leptin was infused intracerebroventricularly at a constant rate in young adult, old and old Wistar rats fasted for 3 months, using osmotic pumps. The effects on body weight, daily food intake, Lee index, adiposity and serum leptin values were analysed. The effect of food restriction on the expression of the long form of leptin receptor in the hypothalamus was also studied.

RESULTS

Leptin decreased daily food intake and body weight in young and old Wistar rats. With a dose of 10 microg/day similar responses were obtained in young and old rats but with a dose of 0.2 microg/day, only young rats showed decreases in these parameters. Food-restriction in old rats lowered adiposity and serum leptin to values close to those of young rats, recovered responsiveness to i.c.v. administration of leptin at the dose of 0.2 microg/day and increased leptin receptor expression in the hypothalamus.

CONCLUSION/INTERPRETATION

Our data show that old Wistar rats have a decreased response to leptin at the central level. Food-restriction recovers leptin responsiveness and increases leptin receptor in the hypothalamus suggesting that adiposity plays a key role in the development of leptin resistance associated with ageing.

Decreased leptin uptake in hypothalamic nuclei with ageing in Wistar rats

Leptin interacts with specific receptors in hypothalamic nuclei and modulates energy balance. Growing evidence has shown the association of obesity and hyperleptinaemia with non-insulin-dependent diabetes mellitus and insulin resistance. The aged Wistar rat shows peripheral insulin resistance in the absence of obesity and alterations of glucose homeostasis. However, it is not known whether, in these animals, the leptin action is altered. Here we studied the effect of ageing on plasma leptin concentration and the ability of hypothalamic nuclei to capture i.c.v.-injected digoxigenin-labelled leptin. Our data indicate that 24-month-old animals are hyperleptinaemic. However, daily food intake was greater in old animals, suggesting that they are leptin resistant. Leptin uptake in the hypothalamus was reduced in old rats. This uptake was a receptor-mediated process as demonstrated by displacement. Leptin accumulation in hypothalamic nuclei was partially colocalized with neuropeptide Y fibres. Immunohistochemical and western blot analyses showed a lower amount of the long form of leptin receptors in the hypothalamus of aged rats. Analysis by RT-PCR also demonstrated a decreased expression of leptin receptor mRNA in old animals. We conclude that the lower leptin uptake may be explained, at least in part, by a decreased amount of receptors in hypothalamic neurones of the aged rats.

Design of a sequencing batch reactor sequence with an input load partition in a simulation-based experimental environment

A study is presented that considers optimization of a sequencing batch reactor (SBR) operational sequence. Optimization is performed with the aid of a laboratory pilot plant and a process model. The model was included in the study to facilitate a search for optimal operating conditions because performing experiments solely on the pilot plant would be rather extensive, expensive, and time-consuming. The model used in the study is the well-known Activated Sludge Model No.1 with minor modifications. The optimization addresses a split-feed operating mode with input load partitioned into two parts and with two successions of aerobic-anoxic phases. In the study, the duration of batch phases and the time of the second input addition are optimized so that the desired effluent nitrogen concentration is achieved and the need for external carbon addition in the anoxic phase is reduced or eliminated. When an optimal SBR sequence computed by the model was verified on the pilot plant, better performance of the actual process was also achieved, although some phenomena were observed that were not predicted by the model. Results of the study indicate that the available wastewater treatment plant models, although a simplification of reality, can be usefully applied for process optimization.

Pre-fermentation of a low-strength meat-processing wastewater in an upflow sludge blanket reactor

Pre-fermentation of low-strength wastewater from a meat processing facility (at 20 degrees C) was studied. A laboratory-scale upflow sludge blanket (USB) reactor was used for the experiments; 10 different operating conditions were tested with regard to the hydraulic residence time (HRT). At HRTs from 0.4 to 2.4 hours, the USB reactor produced effluent with acetate chemical oxygen demand from 82 to 100 mg/L. At HRTs shorter than 0.4 hours and upflow velocities greater than 0.5 m/h, biomass washout was observed. At HRTs longer than 2.4 hours, acetate concentration in the effluent and acetate production efficiency decreased. The transformation of organic nitrogen to ammonia-nitrogen occurred simultaneously with acetate production. Minimal accumulation of biomass in the USB reactor was observed. Pre-fermentation of the low-strength industrial wastewater in the USB reactor could be beneficial for biological nitrogen removal. The produced acetate is directly available for denitrification and the transformed ammonia-nitrogen is directly available for nitrification in the subsequent wastewater treatment steps.

Experimental design of an optimal phase duration control strategy used in batch biological wastewater treatment

The paper presents the design of an algorithm used in control of a sequencing batch reactor (SBR) for wastewater treatment. The algorithm is used for the on-line optimization of the batch phases duration which should be applied due to the variable input wastewater. Compared to an operation with fixed times of batch phases, this kind of a control strategy improves the treatment quality and reduces energy consumption. The designed control algorithm is based on following the course of some simple indirect process variables (i.e. redox potential, dissolved oxygen concentration and pH), and automatic recognition of the characteristic patterns in their time profile. The algorithm acts on filtered on-line signals and is based on heuristic rules. The control strategy was developed and tested on a laboratory pilot plant. To facilitate the experimentation, the pilot plant was superimposed by a computer-supported experimental environment that enabled: (i) easy access to all data (on-line signals, laboratory measurements, batch parameters) needed for the design of the algorithm, (ii) the immediate application of the algorithm designed off-line in the Matlab package also in real-time control. When testing on the pilot plant, the control strategy demonstrated good agreement between the proposed completion times and actual terminations of the desired biodegradation processes.

Adenosine A(1) receptor in cultured neurons from rat cerebral cortex: colocalization with adenosine deaminase

Adenosine A(1) receptors (A(1)Rs) have been characterized in primary cultures of neurons from cerebral cortex. The specific adenosine A(1) antagonist 8-cyclopentyl-1,3-[(3)H]dipropylxanthine bound to both membranes and intact cells. When saturation experiments were performed in membranes, a K(D) value of 0.76 nM and a B(max) of 57 fmol/mg of protein were obtained. Competition assays revealed a pharmacological profile characteristic of A(1)Rs. The presence of this receptor was further confirmed by RT-PCR analysis. The expression of the receptor showed no significant changes during the period of culture studied, up to 12 days in vitro. A(1)R agonist inhibited forskolin-stimulated adenylyl cyclase, showing the functional coupling of these receptors with the effector. alphaG(i1, 2) protein level, detected by immunoblot, presented an increase during the period of culture. This increase correlated with an increase in the mRNA level of alphaG(i1) but not alphaG(i2). By immunochemical assays, it is shown that these receptors are expressed in both the neuronal cell body and the proximal dendrites. Colocalization of A(1)Rs with microtubule-associated protein 2 and cell surface adenosine deaminase was shown by confocal microscopy. The high degree of colocalization observed between A(1)Rs and ectoadenosine deaminase in neurons could suggest an important role of the enzyme in adenosine-mediated neuromodulation.

Rapid and simple determination of inulin in biological fluids by high-performance liquid chromatography with light-scattering detection

We report a new high-performance liquid chromatography method developed for measuring inulin in plasma and urine using ion moderated partition chromatography and evaporative light-scattering detection. Samples are deproteinized with a zinc acetate and phosphotungstic acid solution and added with melezitose as an internal standard. The chromatographic separation is carried out in 16 min at a flow-rate of 0.6 ml/min using deionized water as the mobile phase. Within-run precision, measured at four different concentrations (0.050 mg/ml, 0.150 mg/ml, 0.300 mg/ml and 1.200 mg/ml), ranges from 1.7 to 3.4% in plasma and from 1.5 to 3.5% in urine. Similarly, between-run precision is in plasma from 2.0 to 4.3% and in urine from 2.0 to 4.4%. Analytical recovery ranges from 97.9 to 100.1% in plasma and from 99.1 to 99.7% in urine, respectively. Detection limit (signal-to-noise ratio=3) is 5 microg/ml both in plasma and urine. The method is simple, sensitive, without interference due to hexoses or drugs commonly taken by patients with renal diseases, and offers the advantage of measuring inulin without previous hydrolysis of the molecule.

Rapid determination of creatinine in serum and urine by ion-pair high-performance liquid chromatography

We report a simple and reliable high performance liquid chromatography method for measuring creatinine in serum and urine. The chromatographic run is performed on a C(18) column after protein precipitation with acetone and addition of cimetidine as an internal standard. The separation is carried out in 20 min at a flow rate of 0.8 ml/min, with a mobile phase consisting of 100 mmol/l sodium dihydrogen phosphate solution, containing 30 mmol/l sodium lauryl sulfate pH 3.0 and acetonitrile (60:36, v/v). The absorbance is monitored at 200 nm. The relationship between creatinine concentration and the creatinine/internal standard peak area is linear up to 1,088 micromol/l. Within-run precision measured at three different creatinine concentrations ranges from 0.89% to 2.34% in serum and from 0.34% to 1.10% in urine. Between-run precision varies from 1.68% to 3.17% in serum and from 1.58% to 1.85% in urine over a wide range of concentrations. Analytical recovery is between 98.71% and 101.25% in serum and between 98.96% and 100.27% in urine. The detection limit is 3.24 micromol/l for a signal-to-noise ratio of 3. The method shows a good linearity with the reference isotope dilution gas chromatography-mass spectrometry procedure (r=0.999), without interferences, even in the presence of high bilirubin concentrations.

The federated healthcare record to support shared diabetes care

In this paper the conception of the federated healthcare record server to support shared diabetes care is described. Business process modelling is applied to describe the shared care for diabetes patients. Typical dialogues between the different users (patient, internist, GPs, and diabetic nurses) are analysed and described in terms of use cases. Next to this modelling three incremental steps are defined to realise the record server based upon results of standardisation. It proves to be successful to design and build this record server on modern technologies like CORBA and JAVA.