Influence of p-cresol on the proteome of the autotrophic nitrifying bacterium Nitrosomonas eutropha C91

In this study, the effect of the organic micropollutant and known inhibitor of nitrification, p-cresol, was investigated on the metabolism of the ammonia oxidizing bacteria (AOB) Nitrosomonas eutropha C91 using MS-based quantitative proteomics. Several studies have demonstrated that AOB are capable of biotransforming a wide variety of aromatic compounds making them suitable candidates for bioremediation, yet the underlying molecular mechanisms are poorly described. The effect of two different concentrations of the aromatic micropollutant p-cresol (1 and 10 mg L(-1)) on the metabolism of N. eutropha C91, relative to a p-cresol absent control, was investigated. Though the rate of nitrification in N. eutropha C91 appeared essentially unaffected at both concentrations of p-cresol relative to the control, the expressional pattern of the proteins of N. eutropha C91 changed significantly. The presence of p-cresol resulted in the repressed expression of several key proteins related to N-metabolism, seemingly impairing energy production in N. eutropha C91, contradicting the observed unaltered rates of nitrification. However, the expression of proteins of the TCA cycle and proteins related to xenobiotic degradation, including a p-cresol dehydrogenase, was found to be stimulated by the presence of p-cresol. This indicates that N. eutropha C91 is capable of degrading p-cresol and that it assimilates degradation intermediates into the TCA cycle. The results reveal a pathway for p-cresol degradation and subsequent entry point in the TCA cycle in N. eutropha C91. The obtained data indicate that mixotrophy, rather than cometabolism, is the major mechanism behind p-cresol degradation in N. eutropha C91.

The Microbial Database for Danish wastewater treatment plants with nutrient removal (MiDas-DK) - a tool for understanding activated sludge population dynamics and community stability

Since 2006 more than 50 Danish full-scale wastewater treatment plants with nutrient removal have been investigated in a project called 'The Microbial Database for Danish Activated Sludge Wastewater Treatment Plants with Nutrient Removal (MiDas-DK)'. Comprehensive sets of samples have been collected, analyzed and associated with extensive operational data from the plants. The community composition was analyzed by quantitative fluorescence in situ hybridization (FISH) supported by 16S rRNA amplicon sequencing and deep metagenomics. MiDas-DK has been a powerful tool to study the complex activated sludge ecosystems, and, besides many scientific articles on fundamental issues on mixed communities encompassing nitrifiers, denitrifiers, bacteria involved in P-removal, hydrolysis, fermentation, and foaming, the project has provided results that can be used to optimize the operation of full-scale plants and carry out trouble-shooting. A core microbial community has been defined comprising the majority of microorganisms present in the plants. Time series have been established, providing an overview of temporal variations in the different plants. Interestingly, although most microorganisms were present in all plants, there seemed to be plant-specific factors that controlled the population composition thereby keeping it unique in each plant over time. Statistical analyses of FISH and operational data revealed some correlations, but less than expected. MiDas-DK (www.midasdk.dk) will continue over the next years and we hope the approach can inspire others to make similar projects in other parts of the world to get a more comprehensive understanding of microbial communities in wastewater engineering.

Linking marine and freshwater growth in western Alaska Chinook salmon Oncorhynchus tshawytscha

The hypothesis that growth in Pacific salmon Oncorhynchus spp. is dependent on previous growth was tested using annual scale growth measurements of wild Chinook salmon Oncorhynchus tshawytscha returning to the Yukon and Kuskokwim Rivers, Alaska, from 1964 to 2004. First-year marine growth in individual O. tshawytscha was significantly correlated with growth in fresh water. Furthermore, growth during each of 3 or 4 years at sea was related to growth during the previous year. The magnitude of the growth response to the previous year's growth was greater when mean year-class growth during the previous year was relatively low. Length (eye to tail fork, L(ETF)) of adult O. tshawytscha was correlated with cumulative scale growth after the first year at sea. Adult L(ETF) was also weakly correlated with scale growth that occurred during freshwater residence 4 to 5 years earlier, indicating the importance of growth in fresh water. Positive growth response to previous growth in O. tshawytscha was probably related to piscivorous diet and foraging benefits of large body size. Faster growth among O. tshawytscha year classes that initially grew slowly may reflect high mortality in slow growing fish and subsequent compensatory growth in survivors. Oncorhynchus tshawytscha in this study exhibited complex growth patterns showing a positive relationship with previous growth and a possible compensatory response to environmental factors affecting growth of the age class.

Angiogenesis in non-Hodgkin's lymphoma: Clinico-pathological correlations and prognostic significance in specific subtypes

The aim of the study was to evaluate angiogenesis in different subtypes of non-Hodgkin's lymphoma (NHL) and to correlate angiogenic scores to clinical endpoints. Pre-therapeutic lymph node biopsies from 308 patients with NHL [107 follicular B-cell lymphoma (FL), 94 diffuse large B-cell lymphoma (DLBCL), 107 peripheral T-cell lymphoma (PTCL)] were studied. Microvessels were scored according to the Chalkley and microvessel density method (MVD) methods. Vascular endothelial growth factor (VEGF) protein expression was evaluated by immunohistochemistry. Both Chalkley and MVD methods showed, that the lymphoma subtypes differed significantly in angiogenic scores (P < 0.001). Angiogenic scores in tumor area were highest in PTCL, and lowest in FL. However, a remarkable high microvessel density was found in interfollicular areas of FL. In FL, high interfollicular MVD scores predicted progressive disease and poorer overall and event-free survival (P = 0.024 and 0.013). High interfollicular Chalkley scores correlated with transformation to DLBCL (P = 0.01). VEGF expression was detected in all NHL subtype, and the strongest expression was found in PTCL. In FL, patients with diffuse VEGF expression in lymphoma cells had poorer overall survival than those with focal expression.

Correlation of Electrophysiology and morphology in myocardial sarcoidosis. A case report

A 44-year-old man with systemic sarcoidosis for 11 years developed myocardial sarcoidosis with left bundle branch block and recurrent ventricular tachycardia prior to death. Autopsy showed granulomas and fibrosis in the myocardium including the left ventricular free wall, septum and His bundle, particular the left bundle branch. This is in accordance with the ECG findings.

In situ detection of bacteria involved in cathodic depolarization and stainless steel surface corrosion using microautoradiography

AIMS

To examine the activity of bacteria involved in cathodic depolarization and surface corrosion on stainless steel in an in situ model system.

METHODS AND RESULTS

The microautoradiographic technique (MAR) was used to evaluate the activity of bacterial populations on stainless steel surfaces with a single cell resolution. Anaerobic uptake and fixation of (14)C-labelled bicarbonate occurred within corrosion sites in the absence of atmospheric hydrogen or other external electron donors, whereas it was taken up and fixed by bacteria at all other stainless steel surfaces in the presence of atmospheric hydrogen. This indicates that the bacteria utilized electrons originating from the corrosion sites due to the ongoing corrosion (cathodic depolarization).

CONCLUSION

Under in situ conditions, bacteria were fixating (14)C-labelled bicarbonate at corrosion sites in the absence of atmospheric hydrogen. This indicates that electrons transferred to the bacteria provided energy for bicarbonate fixation due to cathodic depolarization.

SIGNIFICANCE AND IMPACT OF THE STUDY

Application of the MAR method showed ongoing biocorrosion in the applied in situ model system and allowed in situ examination of bacterial activity on a single cell level directly on a metal surface providing information about potential corrosion mechanisms. Furthermore, application of fluorescence in situ hybridization in combination with MAR allows for identification of the active bacteria.

Mixed carbon sources for nitrate reduction in activated sludge-identification of bacteria and process activity studies

Mixtures of methanol and acetate as carbon source were investigated in order to determine their capacity to enhance denitrification and for analysis of the microbial composition and carbon degradation activity in activated sludge from wastewater treatment plants. Laboratory batch reactors at 20 degrees C were used for nitrate uptake rate (NUR) measurements in order to investigate the anoxic activity, while single and mixed carbon substrates were added to activated sludge. Microautoradiography (MAR) in combination with fluorescence in situ hybridisation (FISH) were applied for microbial analysis during exposure to different carbon sources. The NUR increased with additions of a mixture of acetate and methanol compared with additions of a single carbon source. MAR-FISH measurements demonstrated that the probe-defined group of Azoarcus was the main group of bacteria utilising acetate and the only active group utilising methanol under anoxic conditions. The present study indicated an improved denitrification potential by additions of a mixed carbon source compared with commonly used single-carbon additions. It is also established that Azoarcus bacteria are involved in the degradation of both acetate and methanol in the anoxic activated sludge.

Alternative approaches in off-pump redo coronary artery bypass grafting

BACKGROUND

The recent development of off-pump and minimally invasive techniques in coronary artery bypass grafting (CABG) has provided the surgeon with multiple options in performing redo revascularization procedures.

METHODS

We retrospectively analyzed our early results in off-pump redo CABG procedures. Between January 1998 and January 2000, we performed 55 off-pump redo CABG procedures: 25 through a full sternotomy, 21 through a left posterolateral thoracotomy, 5 using a lower hemi-sternotomy and 4 using a mini anterior thoracotomy with thoracoscopic internal mammary artery harvesting. The mean age of this group was 67.7 years (range 37-85). The mean number of grafts performed in earlier operations was 2.7 (range 1-6) with 51% of grafts still partially or fully open at the time of re-operation. Twenty-six patients (47.3%) had a functioning left internal mammary artery graft to left anterior descending. Preoperative clinical severity scoring predicted a mortality of 9% and morbidity of 30%.

RESULTS

There were no operative or thirty-day infarctions or deaths. Morbidity included pulmonary complications (8), renal failure (1) and bleeding (1) for a total complication rate of 18.9%. The average number of grafts performed was 2.7 (range 1-5) for sternotomy patients and 1.4 (range 1-3) for thoracotomy patients.

CONCLUSIONS

By employing alternative approaches in performing off-pump redo CABG procedures, the surgeon can often avoid injury to pre-existing patent internal mammary grafts as well as the morbidity associated with the use of cardiopulmonary bypass.

Floc-forming properties of polyphosphate accumulating organisms in activated sludge

The physico-chemical characteristics of polyphosphate-accumulating organisms (PAO) involved in enhanced biological phosphorus removal (EBPR) was investigated in order to find a novel method for phosphorus recovery. If the physico-chemical characteristics of PAO are different from those of other main floc components, it may be possible to enrich PAO in bulk water or in the floc material for improved recovery of phosphorus. A combination of shear tests, chemical manipulation, and quantification of PAO by fluorescence in situ hybridization was applied. The microcolony strength of both Rhodocyclus-related PAO and Actinobacteria-related PAO was generally high as no treatment could break up more than 20% of all PAO in microcolonies. In contrast, it was possible to remove 20-40% of the organic matter and other bacterial cells by applying a high pH value or adding EDTA. With that a selective enrichment of PAO in the remaining floc material was possible. The feasibility of applying this selective PAO enrichment in flocs remains to be evaluated in full-scale plants for P-recovery.

Microbial diversity in biofilms from corroding heating systems

Culture-independent investigations of the bacterial diversity and activity in district heating systems with and without corrosion did not make it possible to relate one group of microorganisms with the observed corrosion. Fluorescence in situ hybridization by oligonucleotide probes revealed the dominance of beta-proteobacteria, sulphate reducing prokaryotes and alpha-proteobacteria. Analysis of a clone library from one Danish heating (DH) system showed that the most sequences formed two clusters within the alpha-proteobacteria affiliated to the families Rhizobiaceae and Acetobacteraceae and two clusters within the beta-proteobacteria belonging to the family Comamonadaceae. Functional groups were determined by microautoradiography showing aerobic and anaerobic bacteria (sulphate reducing and methanogenic bacteria). The corrosion study showed that pitting corrosion rates were five to ten times higher than the general corrosion rates, suggesting the presence of biocorrosion. The results indicate that several bacterial groups could be involved in corrosion of DH system piping including sulphate reducing prokaryotes, Acidovorax (within the beta-proteobacteria), methanogenic bacteria and others.

Micromanipulation and further identification of FISH-labelled microcolonies of a dominant denitrifying bacterium in activated sludge

The activated sludge process relies on the formation of strong microbial flocs. The knowledge about dominant floc-forming bacteria is at present very limited, especially from a phylogenetic perspective. In this study, numerous microcolonies in the activated sludge flocs were found to be targeted by a Betaproteobacteria-group-specific oligonucleotide probe using fluorescence in situ hybridization (FISH). Some of these were micromanipulated and further identified by reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing to belong to the Aquaspirillum genus in the Neisseriaceae family. A specific oligonucleotide probe, Aqs997, was designed to target the identified bacteria. A survey in nine different wastewater treatment plants with nutrient removal (WWTP) showed a high abundance of bacteria hybridizing to the oligonucleotide probe developed. Microautoradiography (MAR) combined with FISH on activated sludge incubated with radiolabelled substrate showed uptake of substrate with oxygen, nitrate and nitrite as electron acceptor demonstrating a denitrifying potential of the bacteria investigated. The Aquaspirillum-related bacteria seemed to be abundant denitrifiers in WWTPs with nitrogen removal and they were particularly numerous in plants mainly receiving domestic wastewater, where they constituted up to 30% of all bacteria.

Bacterial composition of activated sludge--importance for floc and sludge properties

Activated sludge flocs consist of numerous constituents which, together with other factors, are responsible for floc structure and floc properties. These properties largely determine the sludge properties such as flocculation, settling and dewaterability. In this paper we briefly review the present knowledge about the role of bacteria in relation to floc and sludge properties, and we present a new approach to investigate the identity and function of the bacteria in the activated sludge flocs. The approach includes identification of the important bacteria and a characterization of their physiological and functional properties. It is carried out by use of culture-independent molecular biological methods linked with other methods to study the physiology and function, maintaining a single cell resolution. Using this approach it was found that floc-forming properties differed among the various bacterial groups, e.g. that different microcolony-forming bacteria had very different sensitivities to shear and that some of them deflocculated under anaerobic conditions. In our opinion, the approach to combine identity with functional analysis of the dominant bacteria in activated sludge by in situ methods is a very promising way to investigate correlations between presence of specific bacteria, and floc and sludge properties that are of interest.

Monitoring and characterisation of bacteria in corroding district heating systems using fluorescence in situ hybridisation and microautoradiography

Presence of biofilm and biocorrosion has been observed in Danish district heating (DH) systems despite very good water quality that was expected to prevent significant microbial growth. The microbiological water quality was investigated in order to identify the dominating bacterial groups on surfaces with corrosion problems. Water samples from 29 DH systems were investigated for the total number of bacteria and presence of sulphate reducing bacteria (SRBs). SRBs were found to be present in more than 80% of the DH systems. The microbial population in samples from 2 DH system (biofilm from a test coupon and an in situ sample from a heat exchanger) was investigated with fluorescence in situ hybridisation, and the results showed significant differences in population composition. Betaproteobacteria was the dominant population in both samples. SRBs were present in both samples but were most numerous in the biofilm from the test coupon. Examination of functional groups based on uptake of radiolabelled acetate (microautoradiography) showed presence of both aerobic and anaerobic bacteria despite the fact that oxygen is not anticipated in DH systems.

Microsatellite analyses of the trout of northwest Mexico

The trout of northwest Mexico represent an undescribed group of fish considered part of the Oncorhynchus mykiss (Pacific trout) complex of species and subspecies. Recent genetic studies have shown these fish to have important genetic diversity and a unique evolutionary history when compared to coastal rainbow trout. Increased levels of allelic diversity have been found in this species at the southern extent of its range. In this study we describe the trout in the Sierra Madre Occidental from the rios Yaqui, Mayo, Casas Grandes and de Bavispe, and their relationship to the more southern distribution of Mexican golden trout (O. chrysogaster) using 11 microsatellite loci. Microsatellite allelic diversity in Mexican trout was high with a mean of 6.6 alleles/locus, average heterozygosity = 0.35, and a mean Fst = 0.43 for all loci combined. Microsatellite data were congruent with previously published mtDNA results showing unique panmictic population structure in the Rio Yaqui trout that differs from Pacific coastal trout and Mexican golden trout. These data also add support for the theory of headwaters transfer of trout across the Continental Divide from tributaries of the Rio de Bavispe into the Rio Casas Grandes. Rio Mayo trout share a close genetic relationship to trout in Rio Yaqui, but sample sizes from the Rio Mayo prevent significant comparisons in this study. Microsatellite analyses show significant allelic frequency differences between Rio Yaqui trout and O. chrysogaster in Sinaloa and Durango Mexico, adding further support for a unique evolutionary status for this group of northwestern Mexican trout.

Health-related quality of life in multiple myeloma patients receiving high-dose chemotherapy with autologous blood stem-cell support

In a population-based study, the Nordic Myeloma Study Group found a survival advantage for high-dose melphalan with autologous blood stem-cell support compared to conventional chemotherapy in myeloma patients under 60 yr of age (risk ratio: 1.62; confidence interval [CI] 1.22-2.15; p = 0.001). A study of health-related quality of life (HRQoL) was integrated in the trial, using the EORTC QLQ-C30 questionnaire. Of the 274 patients receiving intensive therapy 221 (81%) were compared to 113 (94%) of 120 patients receiving conventional melphalan-prednisone treatment. Prior to treatment, there were no statistically significant differences in any HRQoL score between the two groups. One month after the start of induction chemotherapy, the patients on intensive treatment had more sleep disturbance than the control patients. At 6 mo, corresponding to a mean of 52 d after high-dose melphalan, the patients on intensive treatment had moderately lower scores for global QoL and role and social functioning and there was also a significantly higher score for appetite loss. At 12 and 24 mo, the HRQoL was similar to that of the control patients. At 36 mo, there was a trend toward less fatigue, pain, nausea, and appetite loss in the intensive-treatment group. Thus, the 18 mo of prolonged survival seem to be associated with a good health-related quality of life. Despite the moderate HRQoL reduction associated with the early intensive chemotherapy phase, this treatment modality must be regarded as an important step forward in the care of multiple myeloma.

Microthrix parvicella, a specialized lipid consumer in anaerobic-aerobic activated sludge plants

The in situ physiology of the filamentous bacterium Microthrix parvicella was investigated in anaerobic-aerobic dynamic phases in activated sludge with focus on the uptake of long chain fatty acids (LCFA) and growth. When 14C-labeled oleic acid was added to activated sludge with an excessive growth of M. parvicella, only little 14C-CO2 was produced under anaerobic conditions while a lot was produced under aerobic conditions. Microautoradiographic studies revealed that M. parvicella took up oleic acid under both anaerobic and aerobic conditions, while only a few floc formers were able to take it up under anaerobic conditions. Extraction and separation of the radioactive biomass into different lipid fractions showed that the oleic acid was stored mainly as neutral lipids under anaerobic conditions, whereas conversion to membrane phospholipids occurred almost exclusively under aerobic conditions, indicating growth. The surface properties of M. parvicella and other bacteria were characterized by hydrophobic fluorescent microspheres, which showed that M. parvicella was relatively hydrophobic. Furthermore, a surface-associated extracellular lipase activity was observed, indicating the ability of M. parvicella to degrade lipids near the filament surface. The results support the hypothesis that uptake and storage of LCFA as lipids under anaerobic conditions provide an effective competition strategy against bacteria that can only take up LCFA under aerobic conditions. Thus, M. parvicella seems to be a specialized lipid consumer with a physiological potential analogous to PAOs and GAOs being able to take up LCFA (but not short chain fatty acids or glucose) under anaerobic conditions and subsequently use the storage material for growth when nitrate or oxygen are available as electron acceptors.

Quantification of functional groups in activated sludge by microautoradiography

Different functional groups of bacteria in activated sludge from a Danish municipal wastewater treatment plant were investigated and quantified on the basis of their ability to take up acetate under different electron acceptor conditions. The number of bacteria in the different functional groups was quantified by microautoradiography or by fluorescence in situ hybridization (FISH). Uptake of radiolabeled acetate was tested under conditions where oxygen, nitrate, ferric iron, and sulfate served as electron acceptors and under methanogenic conditions. Ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were enumerated by applying oligonucleotide probes (FISH). 80% of the total DAPI count hybridised with a mixture of bacterial probes. Most baceria were able to take up acetate with oxygen or nitrate as electron acceptors (74 and 71% of all DAPI-stained bacteria, respectively). The very similar numbers indicate that the alternating aerobic and anoxic conditions in the wastewater treatment plant investigated favoured the presence of facultative aerobic and denitrifying heterotrophic bacteria. The number of bacteria able to take up acetate under anaerobic conditions was around 8% of the total DAPI count. About half of these were able to take up acetate and store it and were thus probably phosphate-accumulating organisms. The remaining 4% of anaerobic acetate-consuming bacteria were mainly iron reducers. By incubating the sludge samples with specific inhibitors against sulfate reduction and methanogenic activity, it was found that sulfate reducers and methanogenic bacteria constituted approximately 1% and less than 0.5% of the total DAPI count, respectively.

In situ characterization of Nitrospira-like nitrite-oxidizing bacteria active in wastewater treatment plants

Uncultivated Nitrospira-like bacteria in different biofilm and activated-sludge samples were investigated by cultivation-independent molecular approaches. Initially, the phylogenetic affiliation of Nitrospira-like bacteria in a nitrifying biofilm was determined by 16S rRNA gene sequence analysis. Subsequently, a phylogenetic consensus tree of the Nitrospira phylum including all publicly available sequences was constructed. This analysis revealed that the genus Nitrospira consists of at least four distinct sublineages. Based on these data, two 16S rRNA-directed oligonucleotide probes specific for the phylum and genus Nitrospira, respectively, were developed and evaluated for suitability for fluorescence in situ hybridization (FISH). The probes were used to investigate the in situ architecture of cell aggregates of Nitrospira-like nitrite oxidizers in wastewater treatment plants by FISH, confocal laser scanning microscopy, and computer-aided three-dimensional visualization. Cavities and a network of cell-free channels inside the Nitrospira microcolonies were detected that were water permeable, as demonstrated by fluorescein staining. The uptake of different carbon sources by Nitrospira-like bacteria within their natural habitat under different incubation conditions was studied by combined FISH and microautoradiography. Under aerobic conditions, the Nitrospira-like bacteria in bioreactor samples took up inorganic carbon (as HCO(3)(-) or as CO(2)) and pyruvate but not acetate, butyrate, and propionate, suggesting that these bacteria can grow mixotrophically in the presence of pyruvate. In contrast, no uptake by the Nitrospira-like bacteria of any of the carbon sources tested was observed under anoxic or anaerobic conditions.

Kinetics of BCR-ABL fusion transcript levels in chronic myeloid leukemia patients treated with STI571 measured by quantitative real-time polymerase chain reaction

The activated tyrosine kinase, which arises as a result of the balanced t(9,22) translocation in chronic myeloid leukemia (CML), is thought to be essential for the development of the leukemic phenotype. Recently, designer drugs have been introduced which specifically inhibit such specific kinases. Among these, STI571 (Glivec) has entered clinical trials and shown promising activities in chronic phase (CP), accelerated phase (AP) and blast crisis (BC) as evidenced by significant hematological and cytogenetic responses in CML patients. To evaluate the effect of STI571 at the molecular level we have employed quantitative real-time PCR (RQ-PCR) to measure the amount of BCR-ABL fusion transcript in a series of 19 patients treated with STI571, either in CP(11) or in (AP)(8) of the disease for 3--9 months (median 6 months). Employing this method, which is able to detect at least one BCR-ABL+ cell in 500,000, in serial blood and bone marrow specimens we found decreases in transcript levels in 10/11 CP patients, but only in 1/8 of the AP patients. When present such decreases were gradual and became evident only after 3 months of STI571 treatment, and their kinetics in blood closely mirrored those seen in parallel marrow samples. Moreover, decreases were between 10- and 100-fold in 11/13 patients, with only two patients reaching residual disease levels below 10(-2) (a 900-fold decrease). Thus, no patient reached PCR negativity. We conclude that the RQ-PCR method is a highly suitable tool for following the effect of STI571 in CML and that further validation of the method, performed in a prospective manner, will contribute significantly to the elucidation of the proper role of STI571 in CML.