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The recently developed denitrifying ammonium oxidation (DEAMOX) process combines the anammox reaction with autotrophic denitrifying conditions using sulfide as an electron donor for the production of nitrite from nitrate within an anaerobic biofilm. This paper compares a quasisteady-state performance of this process for treatment of baker's yeast wastewater under intermittent and continuous feeding and increasing nitrogen loading rate (NLR) from 300 till 858 mg N/L/d. The average total nitrogen removal slightly decreased on increasing the NLR: from 86 to 79% (intermittent feeding) and from 87 to 84% (continuous feeding). The better performance under continuous feeding was due to a more complete nitrate removal in the former case whereas the ammonia removal was similar for both feeding regimes under the comparable NLR. A possible explanation can be that, during continuous feeding (simultaneous supply of nitrate and sulfide), there were less mass transfer limitations for sulfide oxidizing denitrifiers presumably located in the outer layer of sludge aggregates. On the contrary, the ammonia oxidisers presumably located inside the aggregates apparently suffered from nitrite mass transfer limitations under both the feedings. The paper further describes some characteristics of the DEAMOX sludge. 相似文献
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Biodeterioration of crude oil and oil derived products: a review 总被引:2,自引:0,他引:2
Natalia A. Yemashova Valentina P. Murygina Dmitry V. Zhukov Arpenik A. Zakharyantz Marina A. Gladchenko Vasu Appanna Sergey V. Kalyuzhnyi 《Reviews in Environmental Science and Biotechnology》2007,6(4):315-337
Biodeterioration of crude oil and oil fuels is a serious economic and an environmental problem all over the world. It is impossible
to prevent penetration of microorganisms in oil and fuels both stored in tanks or in oilfields after drilling. Both aerobic
and anaerobic microorganisms tend to colonise oil pipelines and oil and fuel storage installations. Complex microbial communities
consisting of both hydrocarbon oxidizing microorganisms and bacteria using the metabolites of the former form an ecological
niche where they thrive. The accumulation of water at the bottom of storage tanks and in oil pipelines is a primary prerequisite
for development of microorganisms in fuels and oil and their subsequent biological fouling. Ability of microorganisms to grow
both in a water phase and on inter-phase of water/hydrocarbon as well as the generation of products of their metabolism worsen
the physical and chemical properties of oils and fuels. This activity also increases the amount of suspended solids, leads
to the formation of slimes and creates a variety of operational problems. Nowadays various test-systems are utilized for microbial
monitoring in crude oils and fuels; thus allowing an express determination of both the species and the quantities of microorganisms
present. To suppress microbial growth in oils and fuels, both physico-mechanical and chemical methods are applied. Among chemical
methods, the preference is given to substances such as biocides, additives, the anti-freezing agents etc that do not deteriorate
the quality of oil and fuels and are environmentally friendly. This review is devoted to the analysis of the present knowledge
in the field of microbial fouling of crude oils and oil products. The methods utilized for monitoring of microbial contamination
and prevention of their undesirable activities are also evaluated. The special focus is given to Russian scientific literature
devoted to crude oil and oil products biodeterioration. 相似文献
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Bioremediation of oil polluted aquatic systems and soils with novel preparation `Rhoder' 总被引:4,自引:0,他引:4
This paper summarises the experience accumulated duringthe field application of biopreparation `Rhoder' (solely or in a combinationwith preliminary mechanical collection of free oil) for remediation of oil polluted aquatic systems and soils in the Moscow region and Western Siberia during 1994–1999.It was demonstrated that `Rhoder' had a very high efficiency (>99%) for bioremediation of the open aquatic surfaces (100 m2 bay of the River Chernaya, two 5,000 m2 lakes in Vyngayakha) at initial level of oil pollution of 0.4–19.1 g/l. During remediation of the wetland (2,000 m2) in Urai (initial level of oil pollution of 10.5 g/l), a preliminary mechanical collection of oil was applied (75% removal) followed by a triple treatment with `Rhoder'. It resulted in an overall treatment efficiency of 94%. Relatively inferior results of bioremediation of the 10,000 m2 wetland in Vyngayakha (65% removal) and the 1,000 m2 marshy peat soil in Nizhnevartovsk (19% removal) can be attributed to the very high initial level of oil pollution (24.3 g/l and >750 g/g dry matter, respectively) aggravated by the fact that it was impossible to apply a preliminary mechanical collection of oil on these sites. A possible strategy for remediation of such heavily polluted sitesis discussed. 相似文献
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S. V. Kalyuzhnyi N. M. Shestakova T. P. Tourova A. B. Poltaraus M. A. Gladchenko A. I. Trukhina T. N. Nazina 《Microbiology》2010,79(2):237-246
The phylogenetic diversity of a microbial community involved in anaerobic oxidation of ammonium nitrogen in the DEAMOX process
was studied. Analysis of clone libraries containing 16S rRNA gene inserts of Bacteria, (including Planctomycetes) and Archaea revealed the presence of nucleotide sequences of the microorganisms involved in the main reactions of the carbon, nitrogen,
and sulfur cycles, including nitrifying, denitrifying, and ANAMMOX bacteria. In the bacterial clone library, 16S rRNA gene
sequences of representatives of the phyla Proteobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Verrucomicrobia, Lentisphaerae, Spirochaetales, and Planctomycetes, as well as of some new groups, were detected. In the archaeal clone library, nucleotide sequences of methanogens belonging
to the orders Methanomicrobiales, Methanobacteriales, and Methanosarcinales were found. It is possible that both ANAMMOX bacteria and bacteria of the genus Nitrosomonas are involved in anaerobic ammonium oxidation in the DEAMOX reactor. Many sequences were similar to those from the clone libraries
obtained previously from the ANAMMOX community of marine sediments. It is also probable that the DEAMOX reactions occur in
natural ecosystems (in marine and freshwater sediments and the oceanic water column), thereby providing for the coupling of
the nitrogen and sulfur cycles. 相似文献
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Samaiya A Deo SS Thulkar S Hazarika S Kumar S Parida DK Shukla NK 《World journal of surgical oncology》2005,3(1):3-7
BACKGROUND: Malignant small bowel tumors are very rare and leiomyosarcoma accounts for less than 15% of the cases. Management of these tumors is challenging in view of nonspecific symptoms, unusual presentation and high incidence of metastasis. In this case report, an unusual presentation of jejunal sarcoma and management of liver metastasis with radiofrequency ablation (RFA) is discussed. CASE PRESENTATION: A 45-year-old male presented with anemia and features of small bowel obstruction. Operative findings revealed a mass lesion in jejunum with intussusception of proximal loop. Resection of bowel mass was performed. Histopathological findings were suggestive of leiomyosarcoma. After 3-years of follow-up, the patient developed recurrence in infracolic omentum and a liver metastasis. The omental mass was resected and liver lesion was managed with radiofrequency ablation. CONCLUSION: Jejunal leiomyosarcoma is a rare variety of malignant small bowel tumor and a clinical presentation with intussusception is unusual. We suggest that an aggressive management approach using a combination of surgery and a newer technique like RFA can be attempted in patients with limited metastatic spread to liver to prolong the long-term survival in a subset of patients. 相似文献
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JINDŘIŠKA BOJKOVÁ KLÁRA KOMPRDOVÁ TOMÁŠ SOLDÁN SVĚTLANA ZAHRÁDKOVÁ 《Freshwater Biology》2012,57(12):2550-2567
1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area. 相似文献
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Mailloux RJ Lemire J Kalyuzhnyi S Appanna V 《Extremophiles : life under extreme conditions》2008,12(3):451-459
Aluminum (Al), an environmental toxin, is known to have a negative impact on various biological systems. However, some microbes
have devised intricate mechanisms to combat the toxic influence of this trivalent metal. In this study, Pseudomonas fluorescens grown in malate invoked a unique metabolic shift to promote the synthesis of citrate, a metabolite involved in the sequestration
of Al. Electrophoretic and spectrophotometric assays revealed several malate-metabolizing enzymes including malate dehydrogenase
(MDH) and malic enzyme (ME) displayed increases in activity and expression in the Al-treated cells. Whereas pyruvate dehydrogenase
(PDH) also showed increased activity and expression in the Al-stressed cultures, phosphoenolpyruvate carboxykinase (PEPCK)
displayed a marked diminution in the Al-treated cells. The upregulation of citrate synthase (CS) coupled with the diminished
activities of aconitase (ACN) and NAD-isocitrate dehydrogenase (NAD-ICDH) appeared to be instrumental in the accumulation
of citrate. HPLC experiments revealed high levels of citrate in the Al-stressed cultures. Thus, an Al-enriched environment
provoked a metabolic shift in P. fluorescens dedicated to the conversion of malate to citrate. 相似文献
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Moderate alcohol consumption is associated with better endothelial function: a cross sectional study
Keiko Suzuki Mitchell SV Elkind Bernadette Boden-Albala Zhezhen Jin Grace Berry Marco R Di Tullio Ralph L Sacco Shunichi Homma 《BMC cardiovascular disorders》2009,9(1):1-5