scholarly journals Critical design factors for polyvinyl alcohol hydrogel entrapping ammonia-oxidizing bacteria: biomass loading, distribution of dissolved oxygen, and bacterial liability

2020 ◽  
Vol 26 (2) ◽  
pp. 200010-0
Author(s):  
Nguyen Thi Minh ◽  
Minkyu Choi ◽  
Nohback Park ◽  
Hyokwan Bae
Keyword(s):  
Outer Layer ◽  
Dead Cell ◽  
Ammonia Oxidizing Bacteria ◽  
The Novel ◽  
Ammonium Oxidation ◽  
Oxygen Inhibition ◽  
Oxygen Penetration ◽  
Cell Staining ◽  
Specific Oxygen Uptake Rate ◽  
Design Factors

The single-stage configuration of the partial nitritation (PN)–anaerobic ammonium oxidation (AMX) process is preferred due to low pH fluctuation and the low concentration of inhibitory NO2-. The novel core-shell structure integrates ammonia-oxidizing reaction in the outer layer to protect AMX bacteria in the core gel bead from oxygen inhibition and provide NO2-. Here, the initial activity of ammonia-oxidizing bacteria (AOB) in the outer layer was assessed by the specific oxygen uptake rate (OUR). AOB activity was positively correlated with biomass loading in the outer layer. A maximum OUR of 10.5 mg-DO/L∙h was achieved with AOB loading of 0.23 mg-VSS per bead. During AOB enrichment, the NO2- production rate was linearly increased up to 0.65 kg-N/m3-d for 17 days (PVA hydrogel packing ratio=17%). The maximum oxygen penetration depth (OPD) was reduced from 966.7±52.3 μm before enrichment to 333.3±36.4 μm after the AOB enrichment. The liable bacteria were observed within a range of 165 μm of the outer layer using the live and dead cell staining. Based on the OPD and liable cell distribution results, a minimal outer layer thickness of approximately 350 μm was suggested to facilitate a successful PN–AMX process.

Clothing and the oceanic identity in Melville’s Redburn

2021 ◽  
Vol 8 (1-2) ◽  
pp. 29-43
Author(s):  
Daniel S. Traber
Keyword(s):  
Outer Layer ◽  
Social Protest ◽  
The Self ◽  
The Novel ◽  
Visible Sign ◽  
The Way

Herman Melville’s Redburn approaches the topic of corporeal coding via the outer layer of clothing. Throughout the novel, the young protagonist consciously uses clothing as a means of self-representation and expression, deploying fashion to create and position himself in different contexts; for example, taking pride in his ragged clothes amongst well-dressed ship passengers becomes a form of social protest. But Redburn is also used to comic effect because his choices are often based on incorrect assumptions of propriety, such as his notion of the way a sailor is supposed to dress not matching the onboard reality. The rules of appearance that construct and restrain an identity are paradoxically bolstered at the same time they are broken, which allows Melville the opportunity to explore rebellion alongside the performative aspect of the self as a body constituting both a visible sign and a living vehicle for the mores, beliefs and ideologies that shape a society.

scholarly journals Changes in the nitrogen biogeochemical cycle in sediments of an urban river under different dissolved oxygen levels

2018 ◽  
Vol 19 (4) ◽  
pp. 1271-1278 ◽  
Author(s):  
Yaping Zhang ◽  
Xiaohong Ruan ◽  
Wenli Shi
Keyword(s):  
Dissolved Oxygen ◽  
Nitrogen Cycling ◽  
Quantitative Polymerase Chain Reaction ◽  
Nitrogen Transformation ◽  
Urban River ◽  
Ammonia Oxidizing Bacteria ◽  
Urban Rivers ◽  
Ammonium Oxidation ◽  
Microbial Nitrogen ◽  
Concentration Changes

Abstract Urban rivers are considered as a hot spot of microbial nitrogen cycling due to extensive N loading. However, microbial nitrogen transformation dynamics in urban rivers with different dissolved oxygen (DO) conditions are still unclear. This study investigated the effects of DO concentration changes (anaerobic to aerobic) in overlying water on nitrogen-cycling gene abundance in incubation conditions using sediment from a typical urban river in the Yangtze River Delta. Quantitative polymerase chain reaction (qPCR) results revealed that the abundances of the nitrification gene amoA, denitrification gene nirS/K, norB, nosZ, and anammox gene hzo increased by one to two orders of magnitude from anaerobic to aerobic conditions. Ammonia-oxidizing archaea (AOA) predominated the ammonium oxidation microbial populations, about tenfold more than the ammonia-oxidizing bacteria (AOB) populations. Significant correlations were found among the abundances of AOA-amoA, AOB-amoA, nirS, nirK, and hzo genes, implying a close coupling of aerobic ammonium oxidation (AAO), denitrification, and anammox processes at the molecular level. Moreover, the nitrogen transformation rates were calculated using a box model linking the measured dissolved inorganic nitrogen species. The contribution of anammox to N2 production was 85% under saturated treatment, and the AAO rate was significantly positive correlated to the anammox rate. Our results suggested that coupled AAO and anammox might be the dominant pathway for reactive nitrogen removal in urban rivers with elevated DO levels.

scholarly journals ATM Induces Cell Death with Autophagy in Response to H2O2 Specifically in Caenorhabditis elegans Nondividing Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Takahito Moriwaki ◽  
Akira Yamasaki ◽  
Qiu-Mei Zhang-Akiyama
Keyword(s):  
Cell Death ◽  
Caenorhabditis Elegans ◽  
Somatic Cells ◽  
Dead Cell ◽  
C Elegans ◽  
Cell Staining ◽  
Dna Damaging Agents ◽  
Gfp Reporter ◽  
Wide Range ◽  
Reporter Assays

Introduction. Ataxia-telangiectasia-mutated (ATM) kinase is a master regulator of the DNA damage response and is directly activated by reactive oxygen species (ROSs) in addition to DNA double-stranded breaks. However, the physiological function of the response to ROSs is not understood. Purpose. In the present study, we investigated how ATM responds to ROSs in Caenorhabditis elegans (C. elegans). Materials and Methods. First, we measured sensitivities of larvae to DNA-damaging agents and ROSs. Next, we analyzed the drug sensitivities of fully matured adult worms, which consist of nondividing somatic cells. Dead cell staining with acridine orange was performed to visualize the dead cells. In addition, we performed GFP reporter assays of lgg-1, an autophagy-related gene, to determine the types of cell death. Results. atm-1(tm5027) larvae showed a wide range of sensitivities to both DNA-damaging agents and ROSs. In contrast, fully matured adult worms, which consist of nondividing somatic cells, showed sensitivity to DNA-damaging agent, NaHSO3, but they showed resistance to H2O2. Dead cell staining and GFP reporter assays of lgg-1 suggest that C. elegans ATM-1 induces the cell death with autophagy in intestinal cells in response to H2O2. Conclusion. We revealed that ATM induces cell death in response to H2O2.

scholarly journals Nitrification mainly driven by ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in an anammox-inoculated wastewater treatment system

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jing Lu ◽  
Yiguo Hong ◽  
Ying Wei ◽  
Ji-Dong Gu ◽  
Jiapeng Wu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
High Throughput Sequencing ◽  
High Efficiency ◽  
Ammonia Oxidation ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Strong Activity ◽  
Nitrite Oxidizing Bacteria

AbstractAnaerobic ammonium oxidation (anammox) process has been acknowledged as an environmentally friendly and time-saving technique capable of achieving efficient nitrogen removal. However, the community of nitrification process in anammox-inoculated wastewater treatment plants (WWTPs) has not been elucidated. In this study, ammonia oxidation (AO) and nitrite oxidation (NO) rates were analyzed with the incubation of activated sludge from Xinfeng WWTPs (Taiwan, China), and the community composition of nitrification communities were investigated by high-throughput sequencing. Results showed that both AO and NO had strong activity in the activated sludge. The average rates of AO and NO in sample A were 6.51 µmol L−1 h−1 and 6.52 µmol L−1 h−1, respectively, while the rates in sample B were 14.48 µmol L−1 h−1 and 14.59 µmol L−1 h−1, respectively. The abundance of the nitrite-oxidizing bacteria (NOB) Nitrospira was 0.89–4.95 × 1011 copies/g in both samples A and B, the abundance of ammonia-oxidizing bacteria (AOB) was 1.01–9.74 × 109 copies/g. In contrast, the abundance of ammonia-oxidizing archaea (AOA) was much lower than AOB, only with 1.28–1.53 × 105 copies/g in samples A and B. The AOA community was dominated by Nitrosotenuis, Nitrosocosmicus, and Nitrososphaera, while the AOB community mainly consisted of Nitrosomonas and Nitrosococcus. The dominant species of Nitrospira were Candidatus Nitrospira defluvii, Candidatus Nitrospira Ecomare2 and Nitrospira inopinata. In summary, the strong nitrification activity was mainly catalyzed by AOB and Nitrospira, maintaining high efficiency in nitrogen removal in the anammox-inoculated WWTPs by providing the substrates required for denitrification and anammox processes.

Transition of bacterial spatial organization in a biofilm monitored by FISH and subsequent image analysis

2004 ◽  
Vol 49 (11-12) ◽  
pp. 365-370 ◽  
Author(s):  
Y. Aoi ◽  
S. Tsuneda ◽  
A. Hirata
Keyword(s):  
Image Analysis ◽  
Outer Layer ◽  
Spatial Organization ◽  
Heterotrophic Bacteria ◽  
Great Influence ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrite Oxidizing Bacteria ◽  
Growth Activity ◽  
Do Concentration

The dynamic transition of bacterial community structure in a biofilm was monitored by the fluorescence in situ hybridization (FISH) technique and subsequent image analysis. Heterotrophic bacteria that had occupied the outer layer were gradually decreased whereas ammonia-oxidizing bacteria (AOB) gradually increased their growth activity and extended their existence area to the outer layer of the biofilm through the gradual reduction of the C/N ratio. The spatial organization of AOB in the biofilm dynamically changed responding to the environmental conditions such as pH fluctuation and lack of dissolved oxygen (DO) and had great influence on the nitrification activity. The accumulation of nitrite was observed at lower DO concentration, which might be due to the property that nitrite-oxidizing bacteria (NOB) possess of higher Km values for oxygen than AOB.

scholarly journals Characterization of an Autotrophic Nitrogen-Removing Biofilm from a Highly Loaded Lab-Scale Rotating Biological Contactor

2003 ◽  
Vol 69 (6) ◽  
pp. 3626-3635 ◽  
Author(s):  
Kris Pynaert ◽  
Barth F. Smets ◽  
Stijn Wyffels ◽  
Daan Beheydt ◽  
Steven D. Siciliano ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Spatial Organization ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Confocal Scanning Laser Microscopy ◽  
Surface Load ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Rotating Biological Contactor ◽  
N Removal

ABSTRACT In this study, a lab-scale rotating biological contactor (RBC) treating a synthetic NH4 + wastewater devoid of organic carbon and showing high N losses was examined for several important physiological and microbial characteristics. The RBC biofilm removed 89% � 5% of the influent N at the highest surface load of approximately 8.3 g of N m−2 day−1, with N2 as the main end product. In batch tests, the RBC biomass showed good aerobic and anoxic ammonium oxidation (147.8 � 7.6 and 76.5 � 6.4 mg of NH4 +-N g of volatile suspended solids [VSS]−1 day−1, respectively) and almost no nitrite oxidation (< 1 mg of N g of VSS−1 day−1). The diversity of aerobic ammonia-oxidizing bacteria (AAOB) and planctomycetes in the biofilm was characterized by cloning and sequencing of PCR-amplified partial 16S rRNA genes. Phylogenetic analysis of the clones revealed that the AAOB community was fairly homogeneous and was dominated by Nitrosomonas-like species. Close relatives of the known anaerobic ammonia-oxidizing bacterium (AnAOB) Kuenenia stuttgartiensis dominated the planctomycete community and were most probably responsible for anoxic ammonium oxidation in the RBC. Use of a less specific planctomycete primer set, not amplifying the AnAOB, showed a high diversity among other planctomycetes, with representatives of all known groups present in the biofilm. The spatial organization of the biofilm was characterized using fluorescence in situ hybridization (FISH) with confocal scanning laser microscopy (CSLM). The latter showed that AAOB occurred side by side with putative AnAOB (cells hybridizing with probe PLA46 and AMX820/KST1275) throughout the biofilm, while other planctomycetes hybridizing with probe PLA886 (not detecting the known AnAOB) were present as very conspicuous spherical structures. This study reveals that long-term operation of a lab-scale RBC on a synthetic NH4 + wastewater devoid of organic carbon yields a stable biofilm in which two bacterial groups, thought to be jointly responsible for the high autotrophic N removal, occur side by side throughout the biofilm.

scholarly journals Nitrogen Removal Efficiency for Pharmaceutical Wastewater with a Single-Stage Anaerobic Ammonium Oxidation Process

2020 ◽  
Vol 17 (21) ◽  
pp. 7972
Author(s):  
Lushen Zuo ◽  
Hong Yao ◽  
Huayu Li ◽  
Liru Fan ◽  
Fangxu Jia
Keyword(s):  
Nitrogen Removal ◽  
Oxygen Demand ◽  
Single Stage ◽  
Anaerobic Ammonium Oxidation ◽  
Ammonium Concentration ◽  
Nitrite Accumulation ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonium Oxidation ◽  
Pharmaceutical Wastewater ◽  
High Concentrations

A single-stage anaerobic ammonium oxidation (ANAMMOX) process with an integrated biofilm–activated sludge system was carried out in a laboratory-scale flow-through reactor (volume = 57.6 L) to treat pharmaceutical wastewater containing chlortetracycline. Partial nitrification was successfully achieved after 48 days of treatment with a nitrite accumulation of 70%. The activity of ammonia oxidizing bacteria (AOB) decreased when the chemical oxygen demand (COD) concentration of the influent was 3000 mg/L. When switching to the single-stage ANAMMOX operation, (T = 32–34 °C, DO = 0.4–0.8 mg/L, pH = 8.0–8.5), the total nitrogen (TN) removal loading rate and efficiency were 1.0 kg/m3/d and 75.2%, respectively, when the ammonium concentration of the influent was 287 ± 146 mg/L for 73 days. The findings of this study imply that single-stage ANAMMOX can achieve high nitrogen removal rates and effectively treat pharmaceutical wastewater with high concentrations of COD (1000 mg/L) and ammonium.

scholarly journals A critical review on the effects of antibiotics on anammox process in wastewater

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Elnaz Jafari Ozumchelouei ◽  
Amir Hossein Hamidian ◽  
Yu Zhang ◽  
Min Yang
Keyword(s):  
Protein Synthesis ◽  
Critical Review ◽  
Environmental Changes ◽  
Cost Effective ◽  
Ammonia Oxidizing Bacteria ◽  
Toxic Substances ◽  
Ammonium Oxidation ◽  
Significant Interest ◽  
Nitrogen Elimination ◽  
Anammox Process

AbstractAnaerobic ammonium oxidation (anammox) has recently become of significant interest due to its capability for cost-effective nitrogen elimination from wastewater. However, anaerobic ammonia-oxidizing bacteria (AnAOB) are sensitive to environmental changes and toxic substances. In particular, the presence of antibiotics in wastewater, which is considered unfavorable to the anammox process, has become a growing concern. Therefore, it is necessary to evaluate the effects of these inhibitors to acquire information on the applicability of the anammox process. Hence, this review summarizes our knowledge of the effects of commonly detected antibiotics in water matrices, including fluoroquinolone, macrolide, β-lactam, chloramphenicol, tetracycline, sulfonamide, glycopeptide, and aminoglycoside, on the anammox process. According to the literature, the presence of antibiotics in wastewater could partially or completely inhibit anammox reactions, in which antibiotics targeting protein synthesis or DNA replication (excluding aminoglycoside) were the most effective against the AnAOB strains.

scholarly journals The specifics of the implementation of the concept of “Antichrist” in the novel by D. S. Merezhkovsky “Peter and Alexey”

2021 ◽  
pp. 115-127
Author(s):  
Tatiana A. Neverova
Keyword(s):  
Outer Layer ◽  
Deep Layer ◽  
Middle Layer ◽  
Frame Structure ◽  
Early 20Th Century ◽  
Distributional Analysis ◽  
The Novel ◽  
The Third ◽  
John The Baptist

The article is devoted to the study of the concept of “Antichrist” in the language picture of the world by D. S. Merezhkovsky. The relevance of the study is due to the significant role of the writer in the literature of the late 19th-early 20th century and the dominance of religious and philosophical ideas in his work. The work is aimed at identifying the specifics of the implementation of the concept of “Antichrist” as one of the key concepts for D.S. Merezhkovsky, analyzing its structure and main representations. The material for the study was the text of the novel “Peter and Alexey”, which was studied using the methods of component, frame and distributional analysis. The paper considers three layers of the concept: the outer layer, which corresponds to the biblical text and represents an literary reconstruction of the eschatological popular consciousness of the 23th and 18th centuries, the middle layer, which contains the idea of Peter as the Antichrist, and the deep layer, formed by the idea of the Antichrist as an entity inextricably linked with Christ in the struggle and unity at the same time. As a result of comparison with one of the first texts that allows us to reconstruct this concept, the Revelation of St. John the Baptist. The differentiating features that make up the peculiarity of the implementation of the concept of “Antichrist” in the text under study are highlighted. It is determined that the outer layer of the concept has a frame structure, and the slots included in it are identified. The semes included in the middle layer of the concept, which has a field structure, are analyzed, the organizing dominant and distributional connections between individual semes are established, which allow combining them into hypersemes. The togetherness of the signification in the third, deep layer of the concept of “Antichrist’s beginning” and “Christ’s beginning” is revealed, which is especially clearly manifested in the fragments that have a mystical character. Based on the analysis of the concept of “Antichrist”, which is widely and variously represented in the text of the novel” Peter and Alexey”, the author concludes that it affects the text and the system of images.

On the Design and Performance of Radical High-Speed Sailing Vehicles

1980 ◽  
Vol 17 (01) ◽  
pp. 50-55
Author(s):  
W. S. Bradfield
Keyword(s):  
High Speed ◽  
International Competition ◽  
The Novel ◽  
The Past ◽  
Straight Line ◽  
Performance Predictions ◽  
Drag Racing ◽  
And Performance ◽  
Short Courses ◽  
Design Factors

A recently established international competition has encouraged straight-line yacht racing over very short courses in flat water with the strongest winds available. The object of this activity is to stimulate the quest for unrestricted sailing vehicle designs which will produce flat-out speed under relatively safe and controlled conditions, thereby pinning down and quantifying design factors governing high-speed yacht performance. This competition has produced a few surprises and some novel and ingenious designs—some successful. The object of the present paper is to discuss and compare some of the novel ideas which have developed into successful drag-racing yachts during the past five years. Performance predictions are compared with measured performance in outstanding cases.

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