The novel genus, 'Candidatus Phosphoribacter', previously identified as Tetrasphaera, is the dominant polyphosphate accumulating lineage in EBPR wastewater treatment plants worldwide.

The bacterial genus Tetrasphaera encompasses abundant polyphosphate accumulating organisms (PAOs) that are responsible for enhanced biological phosphorus removal (EBPR) in wastewater treatment plants. Recent analyses of genomes from pure cultures revealed that 16S rRNA genes cannot resolve the lineage, and that Tetrasphaera spp. are from several different genera within the Dermatophilaceae. Here, we examine 14 recently recovered high-quality metagenome-assembled genomes from wastewater treatment plants containing full-length 16S rRNA genes identified as Tetrasphaera, 11 of which belong to the uncultured Tetrasphaera clade 3. We find that this clade represents two distinct genera, named here Ca. Phosphoribacter and Ca. Lutibacillus, and reveal that the widely used model organism Tetrasphaera elongata is less relevant for physiological predictions of this uncultured group. Ca. Phosphoribacter incorporates species diversity unresolved at the 16S rRNA gene level, with the two most abundant and often co-occurring species encoding identical V1-V3 16S rRNA gene amplicon sequence variants but different metabolic capabilities, and possibly, niches. Both Ca. P. hodrii and Ca. P. baldrii were visualised using fluorescence in situ hybridisation (FISH), and PAO capabilities were confirmed with FISH-Raman microspectroscopy and phosphate cycling experiments. Ca. Phosphoribacter represents the most abundant former Tetrasphaera lineage and PAO in EPBR systems in Denmark and globally.

"Candidatus Accumulibacter delftensis": A clade IC novel polyphosphate-accumulating organism without denitrifying activity on nitrate.

Populations of "Candidatus Accumulibacter", a known polyphosphate-accumulating organism, within clade IC have been proposed to perform anoxic P-uptake activity in enhanced biological phosphorus removal (EBPR) systems using nitrate as electron acceptor. However, no consensus has been reached on the ability of "Ca. Accumulibacter" members of clade IC to reduce nitrate to nitrite. Discrepancies might relate to the diverse operational conditions which could trigger the expression of the Nap and/or Nar enzyme and/or to the accuracy in clade classification. This study aimed to assess whether and how certain operational conditions could lead to the enrichment and enhance the denitrification capacity of "Ca. Accumulibacter" within clade IC. To study the potential induction of the denitrifying enzyme, an EBPR culture was enriched under anaerobic-anoxic-oxic (A2O) conditions that, based on fluorescence in situ hybridization and ppk gene sequencing, was composed of around 97% (on a biovolume basis) of affiliates of "Ca. Accumulibacter" clade IC. The influence of the medium composition, sludge retention time (SRT), polyphosphate content of the biomass (poly-P), nitrate dosing approach, and minimal aerobic SRT on potential nitrate reduction were studied. Despite the different studied conditions applied, only a negligible anoxic P-uptake rate was observed, equivalent to maximum 13% of the aerobic P-uptake rate. An increase in the anoxic SRT at the expenses of the aerobic SRT resulted in deterioration of P-removal with limited aerobic P-uptake and insufficient acetate uptake in the anaerobic phase. A near-complete genome (completeness = 100%, contamination = 0.187%) was extracted from the metagenome of the EBPR biomass for the here-proposed "Ca. Accumulibacter delftensis" clade IC. According to full-genome-based phylogenetic analysis, this lineage was distant from the canonical "Ca. Accumulibacter phosphatis", with closest neighbor "Ca. Accumulibacter sp. UW-LDO-IC" within clade IC. This was cross-validated with taxonomic classification of the ppk1 gene sequences. The genome-centric metagenomic analysis highlighted the presence of genes for assimilatory nitrate reductase (nas) and periplasmic nitrate reductase (nap) but no gene for respiratory nitrate reductases (nar). This suggests that "Ca. Accumulibacter delftensis" clade IC was not capable to generate the required energy (ATP) from nitrate under strict anaerobic-anoxic conditions to support an anoxic EBPR metabolism. Definitely, this study stresses the incongruence in denitrification abilities of "Ca. Accumulibacter" clades and reflects the true intra-clade diversity, which requires a thorough investigation within this lineage.

Plasma Concentrations of Long Chain N-3 Fatty Acids in Early and Mid-Pregnancy and Risk of Early Preterm Birth.

BACKGROUND: Fish oil supplementation has been shown to delay spontaneous delivery, but the levels and clinical significance remain uncertain. We examined the association between plasma fatty acids quantified in pregnancy and subsequent risk of early preterm birth. METHODS: In a case-control design nested in the Danish National Birth Cohort, we identified 376 early preterm cases (<34 gestational weeks, excluding preeclampsia cases) and 348 random controls. Plasma eicosapentaenoic acid plus docosahexaenoic acid (EPA+DHA% of total fatty acids), were measured twice in pregnancy, at gestation weeks 9 and 25 (medians). Odds ratios and 95% confidence intervals (CI's) for associations between EPA+DHA and early preterm risk were estimated by logistic regression, adjusted for the woman's age, height, pre-pregnancy BMI, parity, smoking, and socioeconomic factors. Hypotheses and analytical plan were defined and archived a priori. FINDINGS: Analysis using restricted cubic splines of the mean of 1st and 2nd sample measurements showed a strong and significant non-linear association (p < 0.0001) in which the risk of early preterm birth steeply increased when EPA+DHA concentrations were lower than 2% and flattened out at higher levels. Women in the lowest quintile (EPA+DHA < 1.6%) had 10.27 times (95% confidence interval 6.80-15.79, p < 0.0001) increased risk, and women in the second lowest quintile had 2.86 (95% CI 1.79-4.59, p < 0.0001) times increased risk, when compared to women in the three aggregated highest quintiles (EPA+DHA ≥ 1.8%). INTERPRETATION: Low plasma concentration of EPA and DHA during pregnancy is a strong risk factor for subsequent early preterm birth in Danish women.

Long-term effects of sulphide on the enhanced biological removal of phosphorus: The symbiotic role of Thiothrix caldifontis.

Thiothrix caldifontis was the dominant microorganism (with an estimated bio-volume of 65 ± 3%) in a lab-scale enhanced biological phosphorus removal (EBPR) system containing 100 mg of sulphide per litre in the influent. After a gradual exposure to the presence of sulphide, the EBPR system initially dominated by Candidatus Accumulibacter phosphatis Clade I (98 ± 3% bio-volume) (a known polyphosphate accumulating organism, PAO) became enriched with T. caldifontis. Throughout the different operating conditions studied, practically 100% phosphate removal was always achieved. The gradual increase of the sulphide content in the medium (added to the anaerobic stage of the alternating anaerobic-aerobic sequencing batch reactor) and the adjustment of the aerobic hydraulic retention time played a major role in the enrichment of T. caldifontis. T. caldifontis exhibited a mixotrophic metabolism by storing carbon anaerobically as poly-ß-hydroxy-alkanoates (PHA) and generating the required energy through the hydrolysis of polyphosphate. PHA was used in the aerobic period as carbon and energy source for growth, polyphosphate, and glycogen formation. Apparently, extra energy was obtained by the initial accumulation of sulphide as an intracellular sulphur, followed by its gradual oxidation to sulphate. The culture enriched with T. caldifontis was able to store approximately 100 mg P/g VSS. This research suggests that T. caldifontis could behave like PAO with a mixotrophic metabolism for phosphorus removal using an intracellular sulphur pool as energy source. These findings can be of major interest for the biological removal of phosphorus from wastewaters with low organic carbon concentrations containing reduced S-compounds like those (pre-)treated in anaerobic systems or from anaerobic sewers.

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.

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.

Applicability of experience from laboratory reactors with biological phosphorus removal in full-scale plants.

Enhanced biological phosphorus removal (EBPR) has been used at many wastewater treatment plants all over the world for many years. In this study a full-scale sludge with good EBPR was tested with P-release batch tests and combined FISH/MAR (fluorescence in situ hybridisation and microautoradiography). Proposed models of PAOs and GAOs (polyphosphate- and glycogen-accumulating organisms) and microbial methods suggested from studies of laboratory reactors were found to be applicable also on sludge from full-scale plants. Dependency of pH and the uptake of both acetate and propionate were studied and used for calculations for verifying the models and results from microbial methods. All rates found from the batch tests with acetate were higher than in the batch tests with propionate, which was explained by the finding that only those parts of the bacterial community that were able to take up acetate anaerobically were able to take up propionate anaerobically.

Characterization of thermophilic consortia from two souring oil reservoirs.

The microbial consortia from produced water at two different oil fields in Alaska (Kuparuk) and the North Sea (Ninian) were investigated for sulfate-reducing and methanogenic activity over a range of temperatures and for a variety of substrates. The consortia were sampled on site, and samples were either incubated on site at 60(deg)C with various substrates or frozen for later incubation and analyses. Temperature influenced the rates of sulfate reduction, hydrogen sulfide production, and substrate oxidation, as well as the cell morphology. The highest rates of sulfate reduction and substrate oxidation were found between 50 and 60(deg)C. Formate and n-butyrate were the most favorable electron donors at any tested temperature. Acetate was utilized at 35(deg)C but not at 50 or 70(deg)C and was produced at 60(deg)C. This indicates that the high levels of acetate found in produced water from souring oil formations are due mainly to an incomplete oxidation of volatile fatty acids to acetate. The cell size distribution of the microbial consortium indicated a nonuniform microbial composition in the original sample from the Kuparuk field. At different temperatures, different microbial morphologies and physiologies were observed. Methane-producing activity at thermophilic temperatures (60(deg)C) was found only for the Kuparuk consortium when hydrogen and carbon dioxide were present. No methane production from acetate was observed. Suppression of methanogenic activity in the presence of sulfate indicated a competition with sulfate-reducing bacteria for hydrogen.

Outcome of 328 pregnancies in 205 women with insulin-dependent diabetes mellitus in the county of Northern Jutland from 1976 to 1990.

STUDY OBJECTIVE: To determine the degree of centralization and to describe the outcome of all pregnancies among Type 1 (insulin-dependent) mothers in the county of Northern Jutland from 1976-90. DESIGN: Retrospective, hospital record based study. SETTING: Data were collected from all departments of surgery (n = 8) and obstetrics (n = 3) in the county covering 550,000 inhabitants (approx. 10% of the total Danish population). PATIENTS: Three hundred and twenty-eight consecutive, unselected pregnancies among 205 women with Type 1 diabetes mellitus admitted to the hospitals in the county from 1976-90. MAIN RESULTS: Thirty-two (11%) pregnancies were terminated with spontaneous abortions and ten (3.3%) abortions were induced for medical reasons. There were eleven (4.3%) neonatal deaths. There was no additional fetal loss within the first year of life. Eight (3.1%) babies had major and additionally six (2.4%) minor malformations. Total fetal loss was 53/297 = 18%. Twenty-eight percent of the babies were large-for-gestational age. No pregnancies terminated at primary level hospitals and only 6% at the non-sub specialized obstetrical Departments. CONCLUSION: We have achieved an almost complete centralization of the management of pregnant women with diabetes mellitus and our outcome is comparable to the results published from other regional surveys taking care of these patients.

[Diabetes screening among women who gave birth to heavy infants. The result of 128 glucose tolerance tests during puerperium in women who gave birth to infants weighing 4,500 gram or more, and establishing the screening procedures in Danish maternity clinics]. / Diabetesscreening hos kvinder der har født tunge børn. Resultatet af 128 glukosebelastninger i puerperiet hos kvinder, der har født børn med vaegt over 4,500 gram, samt fastlaeggelse af danske fødesteders screeningsprocedure.

Experience gained from glucose tolerance tests during the puerperium carried out during a period of two years on 129 non-diabetic mothers who had given birth to infants with birth weights of over 4,500 g is presented. Out of 128 completed investigations, only one new case of diabetes was diagnosed. Seven glucose tolerance tests revealed intolerance and six of these were normal on control. No fasting blood sugar levels were over 6.0 mmol/l. These findings correspond to the frequencies of reduced glucose tolerance in a previously published Danish article. In Denmark as a whole, approximately 60% of these women undergo glucose tolerance tests and further 20% are submitted to fasting blood sugar determinations. Glucose tolerance tests during the puerperium based on postprandial blood sugar measurements for two hours is not considered to be suitable as a screening method for diabetes mellitus.

Profundaplasty as the only reconstructive procedure in patients with severe ischemia of the lower extremity.

Twenty-one profundaplasties were performed as the only reconstructive procedure. All of the patients had severe ischemia of the lower extremity with serious symptoms, such as rest pain or gangrene, or both. There was no postoperative mortality. Two patients had a crural amputation, and one patient, a femoral amputation performed during the first three months postoperatively. All of the other patients improved, and there was a significant rise in distal blood pressures after one week, further increasing after three months. At follow-up study, 15 of the patients had considerably less symptoms than preoperatively or were free of symptoms. There was a limb salvage rate of 83 per cent after 60 months. The operation is recommended whenever possible in patients with severe ischemia of the lower extremity when the possibilities of other reconstructive procedures are considered to be poor.

[Recurrent nerve injury after goiter surgery]. / Laesion af nervus recurrens efter strumakirurgi.

During a period of five years, 230 patients were treated operatively on account of benign thyroid disease. The present investigation is particularly directed towards the frequency of transient/permanent and unilateral/bilateral pareses of the vocal cords resulting from lesion of the recurrent nerve during surgical intervention on the thyroid gland. The material consists of 199 women and 31 men. The average age for the entire material was 46 years. Seventy-one patients had been submitted to unilateral intervention and in 159 the intervention was bilateral. Indirect laryngoscopy was carried out on all of the patients before and after operation. The operations were carried out by surgeons-in-charge, registrars, trainee registrars and experienced house surgeons. Transient unilateral pareses developed postoperatively in 17 patients and transient bilateral pareses in five patients. Five patients had permanent unilateral pareses and one patient had permanent bilateral paresis, corresponding to frequencies of pareses of 2.6% and 0.4%. Two patients became chronic tracheostomy cases. Intensive control of vocal cord function and the importance of laryngoscopy are emphasized. The question of the ideal placing of thyroid surgery as regards training and the departments concerned is discussed.

The ischaemic leg: a long-term follow-up with special reference to the predictive value of the systolic digital blood pressure. Part I: No arterial reconstruction.

The course of 53 patients presenting with 76 legs with ischaemia, defined by blood pressure on the big toe below 30 mmHg, were investigated. The series consists of those patients who after an angiography were considered non-candidates for arterial reconstructive surgery. There were 38 limbs with low pressure and severe ischaemic symptoms, i.e. rest pain and/or gangrene and 38 limbs with low pressures and only intermittent claudication or no leg symptoms at all. There were statistically significant differences in the fate of the limbs in the two groups, the first group suffering a 68 per cent risk of amputations compared to only 16 per cent in the second group. The corresponding risk of death was approximately 60 per cent and 10 per cent. The social fate was poor in the group with rest pain and/or gangrene due to the high number of amputations.

The ischaemic leg: a long-term follow-up with special reference to the predictive value of the systolic digital blood pressure. Part II: After arterial reconstruction.

Ninety-five patients with 122 legs with a systolic blood pressure on the big toe below 30 mmHg were the subject of arterial reconstructive surgery. Investigating the limb survival rate we found the systolic blood pressure on the big toe to be the most important predictor, whereas there was found no predictive value of the ankle pressure/index. Preoperative clinical symptoms, which are closely related to the digital blood pressure, were significant predictors of the limb survival rate: the low-pressure limb with no symptoms or intermittent claudication had a significantly higher survival rate than the limb with rest pain and/or gangrene. Following arterial reconstructive surgery the social fate of patients with threatened legs was fairly good as 83% became fully independent.

Postoperative pleural effusion following upper abdominal surgery.

Of 128 patients who underwent upper abdominal surgery, examined by standard preoperative and postoperative chest roentgenograms for the formation of postoperative pleural effusions, 89 had postoperative pleural effusions. Their presence was not related to the type of operation, infection, serum amylases, sex, smoking habits, or weight. There was no correlation between the localization of the pleural effusions and that of the abdominal incisions. There was a positive correlation between atelectasis and pleural effusion, but no evidence of a causal relationship. Pleural effusions might be related to postoperative sodium and water retention, and aggravated by an age-related relative cardiac decompensation. Early postoperative pleural effusions are common and do not require specific treatment.

[The effect of systemic N-acetylcysteine on postoperative expectoration. A prospective, randomized double-blind study]. / Effekten af systemisk administreret N-acetylcystein på postoperativ ekspektoration. En prospektiv, randomiseret, dobbeltblind undersøgelse.

A material of 110 consecutive patients submitted to elective upper abdominal laparotomy participated in a randomized double-blind investigation of the effect of N-acetylcysteine (Mucomyst) administered systemically in the recommended dosage on postoperative expectoration. As an effect variable the quantity of expectorate and the viscosity as assessed subjectively by the physiotherapists in the department on a visual analog scale was employed. N-acetyl-cysteine was not found to have any effect on the postoperative expectoration as assessed by the quantity and the viscosity.

Systemic administration of N-acetylcysteine has no effect on postoperative lung function following elective upper laparotomy in lung healthy patients.

In a randomized, double-blind study, 131 consecutive patients, subjected to elective upper laparotomy, were prophylactically given the recommended dose of N-acetylcysteine (NAC) (Mucomyst, ASTRA) (200 mg x 3) or placebo against postoperative pulmonary complications. The effect was evaluated by lung function tests (VC and FEV1), arterial blood gas analyses and chest x-ray. No benefit could be demonstrated, either to postoperative pulmonary function or in the frequency of atelectasis in the recommended dose. However, no patients with preoperative bronchopulmonary disease demanding treatment with bronchodilatators were included in the study. A positive effect of NAC in this category of patients could not be excluded.

Early diagnosis of postoperative pneumonia following upper abdominal surgery. A study in patients without cardiopulmonary disorder at operation.

In 130 patients with no cardiac or pulmonary disease at the time of elective upper abdominal surgery, chest radiography was performed 2 and 4 days postoperatively. The sputum was examined and the patients were monitored with measurement of body temperature, arterial oxygen tension and white blood counts. Pneumonic infiltrates appeared in 8.4% of the patients and atelectasis in 68.5%. Most of the patients had elevated body temperature, raised white blood count and reduced arterial oxygen tension postoperatively. None of these commonly employed clinical or laboratory findings, singly or in combination, proved adequate for diagnosis of postoperative pneumonia.

Operative pleurodesis in spontaneous pneumothorax. Indications and results.

In 61 cases of spontaneous pneumothorax treated with thoracotomy and pleurodesis, sometimes with resection of bullous lung tissue, the records were reviewed. There were few postoperative complications and no treatment-requiring recurrences. The postoperative drainage time was significantly longer in patients with, than in those without, chronic obstructive pulmonary disease preoperatively, but the long-term results were the same in both groups. Age did not influence the results. The treatment policy in this selected group of patients seemed to be highly satisfactory.

Peroral N-acetylcysteine as prophylaxis against bronchopulmonary complications of pulmonary surgery.

In a randomized, double-blind study, 38 patients undergoing elective pulmonary surgery were given N-acetylcysteine (Fabrol, Ciba-Geigy) in recommended dosage (200 mg X 3) or placebo. The prophylactic effect on postoperative bronchopulmonary complications was evaluated from arterial blood-gas analyses and chest radiography. The alveolo-arterial oxygen difference increased substantially and similarly in both patient groups, and no intergroup difference was found in incidence of atelectasis or pneumonic infiltration. Thus there was no demonstrable benefit of N-acetylcysteine in the recommended dosage. For future similar studies, employment of considerably higher doses is proposed.