The role of myocardial viability assessment in identifying patients with ischemic cardiomyopathy who will benefit from surgical revascularization is controversial. This study assessed myocardial ...viability and its relationship to long-term outcomes in 601 patients with ischemic cardiomyopathy who were assigned to surgical revascularization plus medical therapy or medical therapy alone.
Ionic liquids consisting of a combination of herbicidal anions with a quaternary ammonium cation act as efficient herbicides, which are under consideration to be used in the agriculture. In the ...present study, we used embryos of the zebrafish (Danio rerio) as a model to assess the toxic potential of ammonium-based ionic liquids for aquatic organisms. As we assumed interference of the partially hydrophobic ionic liquid cation with lipids, we investigated the adaptation response in the lipid composition of the zebrafish embryos, triggered by the ionic compound. Therefore, the impact of ammonium-based ionic liquids with different lengths of the alkyl chain (C6,C6,C1,C1NBr, C8,C8,C1,C1NBr) on the phospholipid fatty acid (PLFA) profile of zebrafish embryos up to 72 hours post fertilization (hpf) was examined. Furthermore, the changes in the unsaturation index (UI) of PLFAs, as the sum parameter of membrane fluidity in eukaryotic cells, were presented. The PLFA's UI in the zebrafish embryos upon exposure to quaternary ammonium salts was compared to the UI of the embryos upon exposure to nonionic 2,4-dichlorophenol, which has a similar hydrophobicity but is structurally different to C8,C8,C1,C1NBr. It was shown that for ammonium-based ionic liquid precursors non-specific mode of action occurs and the toxic effect on lipid composition of zebrafish embryos can be well predicted based on chemical properties, like hydrophobicity. Furthermore, the changes in PLFAs, expressed by the UI, can be useful to study toxic effects of organic contamination. However, for zebrafish embryos, after ionic liquids and 2,4-DCP exposure, the changes were observed at high lethal concentrations, which caused the incidence of lethality of 30 and 50% of a group of test animals.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Crude oil-derived hydrocarbons constitute the largest group of environmental pollutants worldwide. The number of reports concerning their toxicity and emphasizing the ultimate need to remove them ...from marine and soil environments confirms the unceasing interest of scientists in this field. Among the various techniques used for clean-up actions, bioremediation seems to be the most acceptable and economically justified. Analysis of recent reports regarding unsuccessful bioremediation attempts indicates that there is a need to highlight the fundamental aspects of hydrocarbon microbiology in a clear and concise manner. Therefore, in this review, we would like to elucidate some crucial, but often overlooked, factors. First, the formation of crude oil and abundance of naturally occurring hydrocarbons is presented and compared with bacterial ability to not only survive but also to utilize such compounds as an attractive energy source. Then, the significance of nutrient limitation on biomass growth is underlined on the example of a specially designed experiment and discussed in context of bioremediation efficiency. Next, the formation of aerobic and anaerobic conditions, as well as the role of surfactants for maintaining appropriate C:N:P ratio during initial stages of biodegradation is explained. Finally, a summary of recent scientific reports focused on the removal of hydrocarbon contaminants using bioaugmentation, biostimulation and introduction of surfactants, as well as biosurfactants, is presented. This review was designed to be a comprehensive source of knowledge regarding the unique aspects of hydrocarbon microbiology that may be useful for planning future biodegradation experiments. In addition, it is a starting point for wider debate regarding the limitations and possible improvements of currently employed bioremediation strategies.
The number of studies dedicated to evaluating the influence of biosurfactants on bioremediation efficiency is constantly growing. Although significant progress regarding the explanation of mechanisms ...behind biosurfactant-induced effects could be observed, there are still many factors which are not sufficiently elucidated. This corresponds to the fact that although positive influence of biosurfactants is often reported, there are also numerous cases where no or negative effect was observed. This review summarizes the recent finding in the field of biosurfactant-amended bioremediation, focusing mainly on a critical approach towards potential limitations and causes of failure while investigating the effects of biosurfactants on the efficiency of biodegradation and phytoextraction processes. It also provides a summary of successive steps, which should be taken into consideration when designing biosurfactant-related treatment processes.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, EMUNI, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK
Abstract Background Patients with ischemic left ventricular dysfunction have higher operative risk with coronary artery bypass graft surgery (CABG). However, those whose early risk is surpassed by ...subsequent survival benefit have not been identified. Objectives This study sought to examine the impact of anatomic variables associated with poor prognosis on the effect of CABG in ischemic cardiomyopathy. Methods All 1,212 patients in the STICH (Surgical Treatment of IsChemic Heart failure) surgical revascularization trial were included. Patients had coronary artery disease (CAD) and ejection fraction (EF) of ≤35% and were randomized to receive CABG plus medical therapy or optimal medical therapy (OMT) alone. This study focused on 3 prognostic factors: presence of 3-vessel CAD, EF below the median (27%), and end-systolic volume index (ESVI) above the median (79 ml/m2 ). Patients were categorized as having 0 to 1 or 2 to 3 of these factors. Results Patients with 2 to 3 prognostic factors (n = 636) had reduced mortality with CABG compared with those who received OMT (hazard ratio HR: 0.71; 95% confidence interval CI: 0.56 to 0.89; p = 0.004); CABG had no such effect in patients with 0 to 1 factor (HR: 1.08; 95% CI: 0.81 to 1.44; p = 0.591). There was a significant interaction between the number of factors and the effect of CABG on mortality (p = 0.022). Although 30-day risk with CABG was higher, a net beneficial effect of CABG relative to OMT was observed at >2 years in patients with 2 to 3 factors (HR: 0.53; 95% CI: 0.37 to 0.75; p<0.001) but not in those with 0 to 1 factor (HR: 0.88; 95% CI: 0.59 to 1.31; p = 0.535). Conclusions Patients with more advanced ischemic cardiomyopathy receive greater benefit from CABG. This supports the indication for surgical revascularization in patients with more extensive CAD and worse myocardial dysfunction and remodeling. (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease STICH; NCT00023595 )
Biogas produced in anaerobic digestion contains energetically useable methane (CH4) and unavoidable unwanted carbon dioxide (CO2). To increase the calorific value of this environmental-friendly ...renewable fuel recovered from wastewater, an upgrading process is necessary to reduce the high concentration of CO2 and increase the associated CH4 content. The pipe-line quality biomethane concentration can be achieved after biologically converting CO2 by either microorganisms or algae. Over the contemporary reviews published on the biogas upgrading, no paper has ever comprehensively covered the emerging biological methods for converting or reducing CO2. Thus, the biotechnologies for CO2 bioconversion such as H2-assisted chemoautotrophic reactor, gas fermentation, microbial electrochemical cells (MEC) and microalgae-based photosynthetic technique are comprehensively reviewed from the aspects of mechanisms, configurations, bottlenecks and efficiencies in this article. The strategies towards improving the performance of each technique regarding CO2 conversion are systematically analysed. The feasibility of each method from economic and environmental perspectives is also outlined. The outlook for biotechnologies with larger scalability and better economic or technical feasibility are then put forward to facilitate their applications for more efficient biogas upgrading.
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•Coupling CO2 with H2 opens a new avenue in the biogas upgrading with challenges.•Gas fermentation obtains potential in removing CO2 from biogas biologically.•MEC has emerged as a possible technology for CO2 sequestration.•Microalgae-based upgrading system should be advanced to improve CO2 availability.•Economic and technique feasibilities of each biotechnology are varied.
The transformation of agrochemicals into herbicidal ionic liquids (HILs) has been suggested as a solution to problems associated with commercial forms of herbicides. The aim of this review was to ...summarize the latest progress in the field of HILs, including their synthesis as well as physicochemical and biological properties, and to address the areas that require further research in order to ensure their safe commercialization (e.g., data regarding biodegradability, toxicity, and environmental fate). The first part of the review provides an in-depth summary of the current state of knowledge regarding HILs, particularly the anions and cations used for their synthesis. The second part highlights the employed synthesis methods and elucidates their respective advantages and limitations. The third section is focused on the characterization of HILs with emphasis on the methods and factors that are significant in terms of their practical application. Subsequently, the issues associated with the biodegradation and toxic effects of HILs are discussed based on the relevant literature reports. All sections include comprehensively tabulated data in order to enable rapid comparison of utilized approaches. Finally, all the findings are critically analyzed in terms of crucial disadvantages (especially the lack of standardization), which allowed us to establish future recommendations and basic guidelines that are presented in the last section.
Why do microorganisms produce rhamnolipids? Chrzanowski, Łukasz; Ławniczak, Łukasz; Czaczyk, Katarzyna
World journal of microbiology & biotechnology,
02/2012, Letnik:
28, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We review the environmental role of rhamnolipids in terms of microbial life and activity. A large number of previous research supports the idea that these glycolipids mediate the uptake of ...hydrophobic substrates by bacterial cells. This feature might be of highest priority for bioremediation of spilled hydrocarbons. However, current evidence confirms that rhamnolipids primarily play a role in surface-associated modes of bacterial motility and are involved in biofilm development. This might be an explanation why no direct pattern of hydrocarbon degradation was often observed after rhamnolipids supplementation. This review gives insight into the current state of knowledge on how rhamnolipids operate in the microbial world.
Abstract Objectives This study sought to test the hypothesis that end-systolic volume (ESV), as a marker of severity of left ventricular (LV) remodeling, influences the relationship between ...myocardial viability and survival in patients with coronary artery disease and LV systolic dysfunction. Background Retrospective studies of ischemic LV dysfunction suggest that the severity of LV remodeling determines whether myocardial viability predicts improved survival with surgical compared with medical therapy, with coronary artery bypass grafting (CABG) only benefitting patients with viable myocardium who have smaller ESV. However, this has not been tested prospectively. Methods Interactions of end-systolic volume index (ESVI), myocardial viability, and treatment with respect to survival were assessed in patients in the prospective randomized STICH (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease) trial of CABG versus medical therapy who underwent viability assessment (n = 601; age 61 ± 9 years; ejection fraction ≤35%), with a median follow-up of 5.1 years. Median ESVI was 84 ml/m2 . Viability was assessed by single-photon emission computed tomography or dobutamine echocardiography using pre-specified criteria. Results Mortality was highest among patients with larger ESVI and nonviability (p < 0.001), but no interaction was observed between ESVI, viability status, and treatment assignment (p = 0.491). Specifically, the effect of CABG versus medical therapy in patients with viable myocardium and ESVI ≤84 ml/m2 (hazard ratio HR: 0.85; 95% confidence interval CI: 0.56 to 1.29) was no different than in patients with viability and ESVI >84 ml/m2 (HR: 0.87; 95% CI: 0.57 to 1.31). Other ESVI thresholds yielded similar results, including ESVI ≤60 ml/m2 (HR: 0.87; 95% CI: 0.44 to 1.74). ESVI and viability assessed as continuous rather than dichotomous variables yielded similar results (p = 0.562). Conclusions Among patients with ischemic cardiomyopathy, those with greater LV ESVI and no substantial viability had worse prognosis. However, the effect of CABG relative to medical therapy was not differentially influenced by the combination of these 2 factors. Lower ESVI did not identify patients in whom myocardial viability predicted better outcome with CABG relative to medical therapy. (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease STICH; NCT00023595 )
The study focused on assessing the influence of bioaugmentation and addition of rhamnolipids on diesel oil biodegradation efficiency during field studies. Initial laboratory studies (measurement of ...emitted CO2 and dehydrogenase activity) were carried out in order to select the consortium for bioaugmentation as well as to evaluate the most appropriate concentration of rhamnolipids. The selected consortium consisted of following bacterial taxa: Aeromonas hydrophila, Alcaligenes xylosoxidans, Gordonia sp., Pseudomonas fluorescens, Pseudomonas putida, Rhodococcus equi, Stenotrophomonas maltophilia, Xanthomonas sp. It was established that the application of rhamnolipids at 150 mg/kg of soil was most appropriate in terms of dehydrogenase activity. Based on the obtained results, four treatment methods were designed and tested during 365 days of field studies: I) natural attenuation; II) addition of rhamnolipids; III) bioaugmentation; IV) bioaugmentation and addition of rhamnolipids. It was observed that bioaugmentation contributed to the highest diesel oil biodegradation efficiency, whereas the addition of rhamnolipids did not notably influence the treatment process.
•Bioremediation of silty-clay soil freshly spiked with diesel oil was conducted.•Bioaugmentation, introduction of rhamnolipids and a mixed approach were evaluated.•Only 3 of the 10 studied consortia had a positive effect upon bioaugmentation.•The use of bioaugmentation increased the TPH removal efficiency by 70%.•Introduction of rhamnolipids had no significant effect on the TPH removal efficiency.
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