Effects of conventionally treated and ozonated wastewater on the damselfly larva oxylipidome in response to on-site exposure

Pharmaceutical residues discharged through insufficiently treated or untreated wastewater enter aquatic environments, where they may adversely impact organisms such as aquatic invertebrates. Ozonation, an advanced wastewater treatment technique, has been successfully implemented to enhance the removal of a broad range of pharmaceuticals, however diverse byproducts and transformation products that are formed during the ozonation process make it difficult to predict how ozonated wastewater may affect aquatic biota. The aim of this study was to investigate effects on fatty acid metabolites, oxylipins, in a common invertebrate species, damselfly larvae, after on-site exposure to conventional wastewater treatment plant (WWTP) effluent and additionally ozonated effluent at a full-scale WWTP. Subsequent ozonation of the conventionally treated wastewater was assessed in terms of i) removal of pharmaceuticals and ii) potential sub-lethal effects on the oxylipidome. Northern damselfly (Coenagrion hastulatum) larvae were exposed for six days in the treatment plant facility to either conventional WWTP effluent or ozonated effluent and the effects on pharmaceutical levels and oxylipin levels were compared with those from tap water control exposure. Ozonation removed pharmaceuticals at an average removal efficiency of 67% (ozone dose of 0.49 g O₃/g DOC). Of 38 pharmaceuticals detected in the effluent, 16 were removed to levels below the limit of quantification by ozonation. Levels of two oxylipins, 12(13)-EpODE and 15(16)-EpODE, were reduced in larvae exposed to the conventionally treated wastewater in comparison to the tap water control. 15(16)-EpODE was reduced in the larvae exposed to ozonated effluent in comparison to the tap water control. One oxylipin, 8-HETE, was significantly lower in larvae exposed to conventional WWTP effluent compared to ozonated effluent. In conclusion, the study provides proof-of-principle that damselfly larvae can be used on-site to test the impact of differentially treated wastewater.

Metabolomics reveals changes in metabolite profiles due to growth and metamorphosis during the ontogeny of the northern damselfly

Many insects have complex life cycles where a drastic ontogenetic change happens between the larval stages and the adult stage, i.e. metamorphosis. Damselflies (order Odonata, suborder Zygoptera) are widely distributed and ecologically important semi-aquatic insects with a complex life cycle. Phenotypic changes over damselfly ontogeny have been documented, however, if and how metabolite profiles are also changing is currently unknown. Here we used a metabolomics methodology to gain insights into the metabolic changes during the life cycle of the Northern damselfly (Coenagrion hastulatum). Hatchlings of wild-caught damselflies were reared in the laboratory and metabolomics analyses using liquid chromatography and gas chromatography coupled to mass spectrometry were carried out at three larval stages and on adult damselflies. Additionally, a subset of larvae was exposed to wastewater effluent to assess how metabolite profiles responded to an environmental stressor. A total of 212 compounds belonging to several classes (e.g. amino acids, fatty acids, sugars) were annotated. Across metamorphosis, we found that damselflies shifted from protein catabolism to lipid catabolism. Wastewater effluent exposure resulted in ontogenetic stage-dependent changes of individual metabolites, but not to a marked extent. Overall, our study is one of the first to describe changes of metabolite profiles during ontogeny of an insect, and it provides a first step towards a greater understanding of the physiological changes occurring during general insect-but especially damselfly-ontogeny.

Oxylipins at intermediate larval stages of damselfly Coenagrion hastulatum as biochemical biomarkers for anthropogenic pollution

Aquatic pollution resulting from anthropogenic activities requires adequate environmental monitoring strategies in sentinel organisms. Thus, biochemical biomarkers have been used as early-warning tools of biological effects in aquatic organisms. However, before using these markers for environmental monitoring, knowledge about their developmental variation is vital. In this study, we assessed baseline levels and developmental variations of a group of potential biomarkers, oxylipins, during the lifespan of the Northern damselfly (Coenagrion hastulatum) using liquid chromatography-tandem mass spectrometry. Effects of wastewater exposure on baseline levels were studied in a subset of damselflies to investigate the responsiveness due to anthropogenic pollution. Thirty-eight oxylipins deriving from four polyunsaturated fatty acids via two enzymatic pathways were detected in damselflies at three larval stages and in the adult form. Overall, oxylipin baseline levels showed developmental variation, which was lowest in the intermediate larval stages. Effects of exposure to wastewater effluent on oxylipin baseline levels were dependent on the life stage and were greatest in the early and intermediate larval stages. The study provides first insights into oxylipin profiles of damselflies at different stages of development and their developmental variation. Based on our results, we propose further strategies for incorporating oxylipins in damselfly larvae as biochemical markers for anthropogenic pollution.

Novel metabolomic method to assess the effect-based removal efficiency of advanced wastewater treatment techniques

Unprecedented levels of chemicals of anthropogenic origin are currently released into surface waters globally. Wastewater treatment plant effluent has been identified as a major source, containing a broad mixture of pharmaceuticals and consumer chemicals. Therefore, there is a need for implementation of advanced wastewater treatment techniques, such as ozonation and adsorption methods, to reduce the contamination. However, there are conflicting findings on the toxicity of treated effluent and only limited possibilities for assessing the effect-based removal efficiency (EBRE) of different treatment techniques. Here, we describe a metabolomics approach to detect perturbations in fatty acid catabolic pathways as a proxy for biological effects. Metabolites in three fatty acid pathways were analyzed in a common damselfly larva (Coenagrion hastulatum) by liquid chromatography coupled to mass spectrometry. The larvae were exposed for one week to either conventionally treated effluent (activated sludge treatment), effluent additionally treated with ozone or effluent additionally treated with biochar filtration and results were compared with those from tap water control exposure. Five lipoxygenase-derived oxylipins (9,10,13-TriHOME, 9,12,13-TriHOME, 9-HODE, 9-HOTrE, and 13-HOTrE) decreased in response to conventionally treated effluent exposure. By using an additional treatment step, oxylipin levels were restored with exception of 9,10,13-TriHOME (ozonated effluent), and 9-HOTrE and 13-HOTrE (effluent filtered with biochar). In conclusion, exposure to wastewater effluent affected fatty acid metabolite levels in damselfly larvae, and a subset of the analyzed metabolites may serve as indicators for biological effects in biota in response to effluent exposure. To that effect, our findings suggest a new metabolomics protocol for assessing EBRE.

LC-MS/MS determination of antiretroviral drugs in influents and effluents from wastewater treatment plants in KwaZulu-Natal, South Africa

South Africa has the largest occurrence of the human immune deficiency virus (HIV) in the world but has also implemented the largest antiretroviral (ARV) treatment programme. It was therefore of interest to determine the presence and concentrations of commonly used antiretroviral drugs (ARVDs) and, also, to determine the capabilities of wastewater treatment plants (WWTPs) for removing ARVDs. To this end, a surrogate standard based LC-MS/MS method was optimized and applied for the detection of thirteen ARVDs used in the treatment and management of HIV/acquired immune deficiency syndrome (HIV/AIDS) in two major and one modular WWTP in the eThekwini Municipality in KwaZulu-Natal, South Africa. The method was validated and the detection limits fell within the range of 2-20 ng L^-1. The analytical recoveries for the ARVDs were mainly greater than 50% with acceptable relative standard deviations. The concentration values ranged from <LOD - 53000 ng L^-1 (influent), <LOD - 34000 ng L^-1 (effluent) in a decentralized wastewater treatment facility (DEWATS); <LOD - 24000 ng L^-1 (influent), <LOD - 33000 ng L^-1 (effluent) in Northern WWTP and 61-34000 ng L^-1 (influent), <LOD - 20000 ng L^-1 (effluent) in Phoenix WWTP. Whilst abacavir, lamivudine and zidovudine were almost completely removed from the effluents, atazanavir, efavirenz, lopinavir and nevirapine persisted in the effluents from all three WWTPs. To estimate the ecotoxicological risks associated with the discharge of ARVDs, a countrywide survey focussing on the occurrence of ARVDs in WWTPs, surface and fresh water bodies, and aquatic organisms, is necessary.

Coordinated nitrogen and carbon remobilization for nitrate assimilation in leaf, sheath and root and associated cytokinin signals during early regrowth of Lolium perenne

Background and Aims

The efficiency of N assimilation in response to defoliation is a critical component of plant regrowth and forage production. The aim of this research was to test the effect of the internal C/N balance on NO3- assimilation and to estimate the associated cytokinin signals following defoliation of perennial ryegrass ( Lolium perenne L. 'Grasslands Nui') plants.

Methods

Plants, manipulated to have contrasting internal N content and contrasting availability of water soluble carbohydrates (WSCs), were obtained by exposure to either continuous light or short days (8:16 h light-dark), and watered with modified N-free Hoagland medium containing either high (5 m m ) or low (50 μ m ) NO3- as sole N source. Half of the plants were defoliated and the root, sheath and leaf tissue were harvested at 8, 24 and 168 h after cutting. The spatiotemporal changes in WSCs, synthesis of amino acids and associated cytokinin content were recorded after cutting.

Key Results

Leaf regrowth following defoliation involved changes in the low- and high-molecular weight WSCs. The extent of the changes and the partitioning of the WSC following defoliation were dependant on the initial WSC levels and the C and N availability. Cytokinin levels varied in the sheath and root as early as 8 h following defoliation and preceded an overall increase in amino acids at 24 h. Subsequently, negative feedback brought the amino acid response back towards pre-defoliation levels within 168 h after cutting, a response that was under control of the C/N ratio.

Conclusions

WSC remobilization in the leaf is coordinated with N availability to the root, potentially via a systemic cytokinin signal, leading to efficient N assimilation in the leaf and the sheath tissues and to early leaf regrowth following defoliation.

Depletion of carbohydrate reserves limits nitrate uptake during early regrowth in Lolium perenne L

The mechanisms linking C/N balance to N uptake and assimilation are central to plant responses to changing soil nutrient levels. Defoliation and subsequent regrowth of grasses both impact C partitioning, thereby creating a significant point of interaction with soil N availability. Using defoliation as an experimental treatment, we investigated the dynamic relationships between plant carbohydrate status and NO3--responsive uptake systems, transporter gene expression, and nitrate assimilation in Lolium perenne L. High- and low-affinity NO3- uptake was reduced in an N-dependent manner in response to a rapid and large shift in carbohydrate remobilization triggered by defoliation. This reduction in NO3- uptake was rescued by an exogenous glucose supplement, confirming the carbohydrate dependence of NO3- uptake. The regulation of NO3- uptake in response to the perturbation of the plant C/N ratio was associated with changes in expression of putative high- and low-affinity NO3- transporters. Furthermore, NO3- assimilation appears to be regulated by the C-N status of the plant, implying a mechanism that signals the availability of C metabolites for NO3- uptake and assimilation at the whole-plant level. We also show that cytokinins may be involved in the regulation of N acquisition and assimilation in response to the changing plant C/N ratio.

Feeding patterns of three sympatric tsetse species (Glossina spp.) (Diptera: Glossinidae) in the preforest zone of Côte d'Ivoire

The feeding patterns of Glossina longipalpis Wiedemann 1830, G. medicorum Austen 1911, G. palpalis gambiensis Vanderplank 1949 and G. p. palpalis Robineau-Desvoidy 1830 are described from natural habitats in central Côte d'Ivoire where these tsetse species occurred sympatrically. Blood-meal identification of tsetse flies revealed that in natural habitats wild ruminants were by far the most frequent source of food for each Glossina species, but there were significant differences between the nutritional spectra of single fly species. G. p. gambiensis fed significantly less often on bushbuck and significantly more often on monitor lizard (Varamus niloticus) than both, G. longipalpis and G. medicorum. In G. p. gambiensis the blood of wild ruminant species was significantly more often found than in G. p. palpalis, whereas the latter fed significantly more often on domestic animals. Peridomestic populations of G. longipalpis and G. p. palpalis fed mostly on domestic pig and therefore had significantly reduced host spectra in comparison to natural populations. The significant differences in feeding patterns among the investigated species, subspecies and populations seem not to depend on species specific feeding preferences. Rather, they can be attributed to microhabitat specialization of the various tsetse groups and hence mainly to the different availability of hosts. This implies that environmental factors should be taken more into account when analysing and comparing the feeding patterns of tsetse.

Natural host odours as possible attractants for Glossina tachinoides and G. longipalpis (Diptera: Glossinidae)

As strictly haematophagous insects, tsetse flies feed on a wide variety of wild and domestic animals. Although these are mainly mammals, some tsetse species also feed on reptiles. The present study investigated whether the odours of several potential natural tsetse hosts may be used as novel attractants to improve the catch of Glossina tachinoides or G. longipalpis in biconical traps. The odour of a living monitor lizard (Varanus niloticus) had no effect on the catch of G. tachinoides. Hexane skin washings of monitor lizard and warthog (Phacochoerus aethiopicus) dispensed in small quantities improved the catch of G. tachinoides significantly by factors of up to 1.34 and 1.46, respectively. Skin washing of bushbuck (Tragelaphus scriptus) did not increase the catch of G. tachinoides, but the synthetic phenolic fraction of bushbuck urine enhanced it significantly by 1.81 times. The catch of G. longipalpis was improved significantly by the urines of warthog, domestic pig and bushbuck by factors of 1.58, 1.91 and 2.51, respectively. In relation to the quantity of evaporated odour, bushbuck and warthog urine seem to be of particular interest for further attractant studies. The effect of tested host odours on the catch of G. tachinoides and G. longipalpis is compared with data of other tsetse species and with the frequency these hosts are fed on by tsetse flies. Bushbuck is one of the principal natural hosts of both Glossina species investigated, and of all odours tested, bushbuck urine and its synthetic phenolic fraction improved the catch of both tsetse species the most.

New cineromycins and musacins obtained by metabolite pattern analysis of Streptomyces griseoviridis (FH-S 1832). II. Structure elucidation

A detailed analysis of the secondary metabolite pattern produced by Streptomyces griseoviridis (strain FH-S 1832) using a chemical screening method resulted in the detection, isolation and structure elucidation of new 14-membered lactones of the cineromycin B-type [dehydrocineromycin B (5), oxycineromycin B (7), and 2,3-dihydrocineromycin B (8)], as well as new gamma-lactones related to nigrosporalactone and 4,5-dihydroxy-octa-2,6-dienoic acid esters named musacins A to F (10, 13 approximately 15, 17, 18 and 21). The constitution of these metabolites were deduced from spectroscopic data as well as chemical transformations. The configuration of musacin D (10) was determined by derivatization with chiral acids (Helmchen's method).

Production and characterization of anti-human interferon gamma receptor antibody fragments that inhibit cytokine binding to the receptor

Three single-chain antibody fragments that recognize the extracellular human interferon gamma receptor alpha-chain (IFN gamma R), and inhibit the binding of human IFN gamma, have been produced in Escherichia coli. These fragments are derived from murine anti-receptor monoclonal antibodies, and comprise the variable heavy (VH) domain linked to the variable light (VL) chain through a 15 amino acid linker [(GGGGS)3]. Using surface plasmon resonance technology (BIAcore), the soluble proteins were shown to retain a high affinity for recombinant IFN gamma R, and by radioimmunoassay to possess a high inhibitory activity towards IFN gamma-binding to human Raji cells. The antibody fragments most likely recognize epitopes that overlap the cytokine binding site on the receptor surface. Attempts to dissect further the antibodies to isolated VH- and VL-chains and to synthetic linear and cyclic peptides derived from the individual complementarity determining regions failed to afford fragments with significant IFN gamma R binding affinity. Nevertheless, these native-like variable region fragments and petidomimetics derived from them are of interest in the design of novel IFN gamma R antagonists.

Olfactory attractants for West African tsetse flies, glossina spp. (Diptera: Glossinidae)

The effect of various natural host odours on Glossina longipalpis, G. medicorum and G. tachinoides from catches in odour-baited biconical traps was analysed. Substances tested were ox urine, and the eight components of its phenolic fraction, as well as acetone and 1-octen-3-ol, both of which are present in ox breath. Ox urine increased the catch of G. tachinoides significantly by 1.2 times. Its phenolic fraction gave increases of up to 1.6 for G. longipalpis and 1.4 for G. tachinoides (significant in both cases). Adding acetone and/or 1-octen-3-ol to the phenolic fraction increased attraction of G. longipalpis and G. tachinoides significantly by up to 1.8 and 1.3 times, respectively. Octenol on its own increased the catch of all three species significantly by up to 2.2 times. Acetone alone, in combination with octenol or with the phenolic fraction reduced the catch of G. medicorum significantly to a level of 0.2. 3-Methylphenol and 4-methylphenol are those components of the phenolic fraction which showed the highest attractiveness on tsetse flies in the experiments. Several mixtures of both methylphenols and/or 1-octen-3-ol were tested as attractants for all three tsetse species.

Natural hosts of Glossina tachinoides (Diptera: Glossinidae) in northern Côte d'Ivoire

Bloodmeal samples of G. tachinoides were taken at the Comoé National Parc in northern Côte d'Ivoire. The total of 1154 identified samples consisted mainly of ruminants (37%, whereof bushbuck represented 57%), hippopotamus (34%), and monitor lizard (19%). These proportions changed with the seasons. In the rainy season the portion of hippopotamus samples increased, whereas that of reptiles decreased. Primate blood was identified only in samples taken in the dry season.

Late pulmonary embolization of a retained pacemaker electrode fragment after attempted transatrial extraction

Embolization of pacemaker electrode fragments into the pulmonary circulation is a rare complication following transvenous pacemaker implantation. One such case is reported here. In a 67-year-old patient, a battery pocket infection developed after transvenous pacemaker implantation and subsequent surgical revision. After removal of the pacemaker and ventricular pacing lead, the atrial lead broke within the superior vena cava when prolonged traction was applied after frustrating attempts to extract the electrode. Attempts to extract the fragment transvenously using endoscopic forceps were unsuccessful. Due to firm fixation of the electrode by extensive fibrous scar tissue in the atrial wall, a further attempt to remove the retained electrode fragment by atriotomy also failed. On the first postoperative day, the fragment migrated to the left pulmonary artery, from where it was successfully extracted by means of a Dormier basket.

Reduction of postoperative donor blood requirement by use of the cell separator

In a prospective, randomized study of 20 patients undergoing elective open-heart surgery, up to c. one-third of the total intraoperative and postoperative transfusion requirement could be provided by autologous centrifuged blood. Retransfusion of washed, packed red blood cells freed from cellular debris, heparin and activated clotting factors significantly reduced blood loss during and after surgery. The cell separator is a valuable aid in autotransfusion technique.

[Ventricle function in low-dose digitoxin in patients with chronic heart failure (stage II/III)]

Using one- and two-dimensional echocardiographic parameters, left ventricular function and dimensions were investigated in 11 patients with chronic heart failure (NYHA stages II-III) and in 10 normal subjects after administration of low-dose digitoxin (0.07 mg). Tests were performed before the begin of therapy, on the 3rd day following rapid saturation, and on the 15th day under maintenance therapy. There was no significant decrease either of heart volume as assessed by X-ray or of enddiastolic volume measured echocardiographically. However--predominantly in patients--a marked decrease in endsystolic diameter (p less than 0.01) and an increase in posterior wall motion amplitude (p less than 0.05) was observed resulting in increased stroke volume, shortening fraction (p less than 0.001). Early diastolic left ventricular filling speed also increased significantly in both groups (p less than 0.01). Changes in these parameters were more pronounced in patients than in normal subjects. In both groups the effects were achieved soon after rapid saturation, increasing slightly during the period of chronic administration of low-dose digitoxin. Parallel to the changes in echocardiographic parameters, a noticeable clinical improvement occurred among patients. No side effects were observed as serum digitoxin levels were in the therapeutic range. It may be concluded that low-dose digitoxin can be employed to increase cardiac contractility in patients with heart failure.

Catheter embolization following median sternotomy

A case of intraoperative internal jugular vein catheter embolization in a patient undergoing median sternotomy for open-heart surgery is described. This complication suggests that right sided cannulation of the internal jugular vein is to be preferred in all patients having a median sternotomy in order to avoid the risk of intersection by median sternotomy.

[Combined use of dihydralazine and nitroglycerin during and after cardiac surgery (author's transl)]

The haemodynamic effect of combined intravenous administration of 18 mg/h dihydralazine and 0.6 mg/h nitroglycerine was examined in the intraoperative and postoperative phases of cardiac surgery (replacement of the aortic and mitral valve or of both valves, and aortocoronary bypass surgery(. Indication for therapy was supplied by a preoperative cardiac index below 2.8 l/min . m2 and an enhanced peripheral resistance above 1200 dyne . sec . cm-5. During a 19-hour observation period the haemodynamic parameters such as cardiac index (+36%) and stroke index (+19%) increased significantly within the investigated group, whereas the peripheral vascular resistance dropped by 16% and the left atrial pressure by 20%. Arterial mean pressure and heart rate did not change. In a patient group treated exclusively with nitroglycerin, the cardiac index decreased (-8%), while the peripheral vascular resistance increased (+6%); an untreated control group showed an increase of the cardiac index by 5%, whereas there was no appreciable change in peripheral vascular resistance and stroke index. The combined use of dihydralazine and nitroglycerin during the perioperative phase of cardiac surgery appears recommendable, since it is possible by such administration to monitor cardiac preload and afterload due to selectivity of the pharmacological sites of action.

[The Haemonetics cell saver in open heart surgery (author's transl)]

A prospective study in 20 patients undergoing open heart surgery showed that up to 48 per cent of the required transfusion volume could be provided by autologous centrifuged blood. Re-transfusion of the washed packed red cells free of cell debris, heparin and aggregate significantly reduced blood loss both during and after the operation. The haemonetics cell saver is a valuable aid in the auto-transfusion technique.

Tissue glue for sealing plastic valves and bioprostheses in the canine aorta

In experiments on seven dogs, a fibrin glue was used to seal plastic valves and bioprostheses in the thoracic aorta. Each valves was fixed in place with only four single sutures. Intraoperative and postoperative angiographic checks, with countercurrent aorta filling, gave no indication of perivalvular leak, even after eight weeks. Histologic studies confirmed the angiographic findings and showed only slight changes in the aortic wall. The results indicate that application of fibrin glue, supplementary to conventional suture procedure, may be useful when satisfactory fixation of aortic valves is hampered by pathologic circumstances.