Nitrite-oxidizing bacteria (NOB) catalyze the second step of nitrification, a major process of the biogeochemical nitrogen cycle, but the recognized diversity of this guild is surprisingly low and ...only two bacterial phyla contain known NOB. Here, we report on the discovery of a chemolithoautotrophic nitrite oxidizer that belongs to the widespread phylum Chloroflexi not previously known to contain any nitrifying organism. This organism, named Nitrolancetus hollandicus, was isolated from a nitrifying reactor. Its tolerance to a broad temperature range (25-63 °C) and low affinity for nitrite (K(s)=1 mM), a complex layered cell envelope that stains Gram positive, and uncommon membrane lipids composed of 1,2-diols distinguish N. hollandicus from all other known nitrite oxidizers. N. hollandicus grows on nitrite and CO(2), and is able to use formate as a source of energy and carbon. Genome sequencing and analysis of N. hollandicus revealed the presence of all genes required for CO(2) fixation by the Calvin cycle and a nitrite oxidoreductase (NXR) similar to the NXR forms of the proteobacterial nitrite oxidizers, Nitrobacter and Nitrococcus. Comparative genomic analysis of the nxr loci unexpectedly indicated functionally important lateral gene transfer events between Nitrolancetus and other NOB carrying a cytoplasmic NXR, suggesting that horizontal transfer of the NXR module was a major driver for the spread of the capability to gain energy from nitrite oxidation during bacterial evolution. The surprising discovery of N. hollandicus significantly extends the known diversity of nitrifying organisms and likely will have implications for future research on nitrification in natural and engineered ecosystems.
•SARS-CoV-2 RNA presence was measured at 24 locations in the Prague sewer network.•Residential areas (100–13,000 inhab.), transport hubs, hospitals etc. were included.•Consistent wastewater ...monitoring by RT-mqPCR took place from August 2020–May 2021.•The sampling of major Prague sewers correlated well with clinical-based data.•Grab samples can identify COVID-19 hotspots in local neighborhoods.
Many reports have documented that the presence of SARS-CoV-2 RNA in the influents of municipal wastewater treatment plants (WWTP) correlates with the actual epidemic situation in a given city. However, few data have been reported thus far on measurements upstream of WWTPs, i.e. throughout the sewer network. In this study, the monitoring of the presence of SARS-CoV-2 RNA in Prague wastewater was carried out at selected locations of the Prague sewer network from August 2020 through May 2021. Various locations such as residential areas of various sizes, hospitals, city center areas, student dormitories, transportation hubs (airport, bus terminal), and commercial areas were monitored together with four of the main Prague sewers. The presence of SARS-CoV-2 RNA was determined by reverse transcription – multiplex quantitative polymerase chain reaction (RT-mqPCR) after the precipitation of nucleic acids with PEG 8,000 and RNA isolation with TRIzol™ Reagent. The number of copies of the gene encoding SARS-CoV-2 nucleocapsid (N1) per liter of wastewater was compared with the number of officially registered COVID-19 cases in Prague. Although the data obtained by sampling wastewater from the major Prague sewers were more consistent than those obtained from the small sewers, the correlation between wastewater-based and clinical-testing data was also good for the residential areas with more than 7,000 registered inhabitants. It was shown that monitoring SARS-CoV-2 RNA in wastewater sampled from small sewers could identify isolated occurrences of COVID-19-positive cases in local neighborhoods. This can be very valuable while tracking COVID-19 hotspots within large cities.
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Anaerobic sewage treatment has been proposed as sustainable sanitation technology with the potential to be energy positive. However, there are very few works dealing with anaerobic degradability ...(i.e. biomethane potential – BMP) of sewage. Until now, no authors systematically studied anaerobic psychrophilic degradation of sewage in sufficient detail, i.e. in batch experiments. In this study, six sewage samples of various origin and quality were tested via BMP experiments with three different samples of inoculum (both adapted and non-adapted), to elucidate the principle kinetics and obtain fundamental engineering data.
The anaerobic biodegradability of sewage at 15 °C varied from 50 to 75%, with the average methane yield 0.22 ± 0.03 m3 kg−1 (CH4, CODadded). According to Monod-based calculations, all sewage samples behaved as two component substrate, while no correlation of biodegradability with different raw sewage quality was observed. The same rate constant (rmax) was found for all tested sewage samples. But, rmax was greatly dependent on inoculum source.
This study provides a fundamental dataset to understand and predict psychrophilic anaerobic sewage utilization. With this knowledge, novel wastewater treatment plant layouts can be designed even in mild/cold climates as well as already existing facilities intensified in terms of energy optimization and recovery.
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•Three inocula have been tested in psychrophilic BMP tests with several different samples.•All sewage samples contained similar portion of SRB (87%) and SSB (13%) substrate.•The same rate constant (rmax = 0.035 d−1) fits for all tested sewage samples.•Anaerobic biodegradability of sewage varied only slightly (62 ± 8%).•Inoculum adapted to 15 °C showed the same activity at 15 °C as the mesophilic at 35 °C.
A novel nitrite-oxidizing bacterium (NOB), strain LbT, was isolated from a nitrifying bioreactor with a high loading of ammonium bicarbonate in a mineral medium with nitrite as the energy source. The ...cells were oval (lancet-shaped) rods with pointed edges, non-motile, Gram-positive (by staining and from the cell wall structure) and non-spore-forming. Strain LbT was an obligately aerobic, chemolitoautotrophic NOB, utilizing nitrite or formate as the energy source and CO2 as the carbon source. Ammonium served as the only source of assimilated nitrogen. Growth with nitrite was optimal at pH 6.8–7.5 and at 40 °C (maximum 46 °C). The membrane lipids consisted of C20 alkyl 1,2-diols with the dominant fatty acids being 10MeC18 and C18 : 1ω9. The peptidoglycan lacked meso-DAP but contained ornithine and lysine. The dominant lipoquinone was MK-8. Phylogenetic analyses of the 16s rRNA gene sequence placed strain LbT into the class Thermomicrobia of the phylum Chloroflexi with Sphaerobacter thermophilus as the closest relative. On the basis of physiological and phylogenetic data, it is proposed that strain LbT represents a novel species of a new genus, with the suggested name Nitrolancea hollandica gen. nov., sp. nov. The type strain of the type species is LbT ( = DSM 23161T = UNIQEM U798T).
Partial nitritation/anammox can provide energy-efficient nitrogen removal from the main stream of municipal wastewater. The main bottleneck is the growth of nitrite oxidizing bacteria (NOB) at low ...temperatures (<15 °C). To produce effluent suitable for anammox, real municipal wastewater after anaerobic pretreatment was treated by enriched ammonium oxidizing bacteria (AOB) in suspended sludge SBR at 12 °C. NOB were continually washed out using aerobic duration control strategy (ADCS). Solids retention time was set to 9-16 days. Using this approach, average ammonia conversion higher than 57% at high oxidation rate of 0.4 ± 0.1 kg-N kg-VSS
d
was achieved for more than 100 days. Nitrite accumulation (N-NO
/N-NO
) of 92% was maintained. Thus, consistently small amounts of present NOB were efficiently suppressed. Our mathematical model explained how ADCS enhanced the inhibition of NOB growth via NH
and HNO
. This approach will produce effluent suitable for anammox even under winter conditions in mild climates.
Hydrogen sulfide is a toxic and usually undesirable by-product of the anaerobic treatment of sulfate-containing wastewater. It can be removed through microaeration, a simple and cost-effective method ...involving the application of oxygen-limiting conditions (i.e., dissolved oxygen below 0.1 mg L
). However, the exact transformation pathways of sulfide under microaerobic conditions are still unclear. In this paper, batch experiments were performed to study biochemical and chemical sulfide oxidation under microaerobic conditions. The biochemical experiments were conducted using a strain of Sulfuricurvum kujiense. Under microaerobic conditions, the biochemical sulfide oxidation rate (in mg S L
d
) was approximately 2.5 times faster than the chemical sulfide oxidation rate. Elemental sulfur was the major end-product of both biochemical and chemical sulfide oxidation. During biochemical sulfide oxidation elemental sulfur was in the form of white flakes, while during chemical sulfide oxidation elemental sulfur created a white suspension. Moreover, a mathematical model describing biochemical and chemical sulfide oxidation was developed and calibrated by the experimental results.
Antibiotic resistance is considered one of the biggest threats to public health and has become a major concern for governments and international organizations. Combating this problem starts with ...improving global surveillance of antibiotic resistance genes (ARGs) and applying standardized protocols, both in a clinical and environmental context, in agreement with the One Health approach. Exceptional efforts should be directed to controlling ARGs conferring resistance to Critically Important Antimicrobials (CIA). In this study, a systematic literature review to synthesize data on the identification of mcr genes using a PCR technique was performed. Additionally, a novel set of PCR primers for mcr-1 – mcr-9 genes detection was proposed. The developed primers were in silico and experimentally validated by comparison with mcr-specific PCR primers reported in the literature. This validation, besides being a proof-of-concept for primers’ usefulness, provided insight into the distribution of mcr genes in municipal wastewater, clay and river sediments, glacier moraine, manure, seagulls and auks feces and daphnids from four countries. This analysis proved that commonly used primers may deliver false results, and some mcr genes may be overlooked in tested samples. Newly-developed PCR primers turned out to be relevant for the screening of mcr genes in various environments.
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•mcr genes conferring resistance to colistin are widespread in the environment.•Commonly used primers may generate false-negative results during PCR screening.•In silico validation of primers reduces the chance of omitting mcr genes.•Novel primers for detection of mcr genes in environmental samples were developed.
To investigate the roles of BCL2, MCL1, and BCL-XL in the survival of diffuse large B-cell lymphoma (DLBCL).
Immunohistochemical analysis of 105 primary DLBCL samples, and Western blot analysis of 18 ...DLBCL cell lines for the expression of BCL2, MCL1, and BCL-XL. Pharmacologic targeting of BCL2, MCL1, and BCL-XL with ABT-199, homoharringtonine (HHT), and ABT-737. Analysis of DLBCL clones with manipulated expressions of BCL2, MCL1, and BCL-XL. Immunoprecipitation of MCL1 complexes in selected DLBCL cell lines. Experimental therapy aimed at inhibition of BCL2 and MCL1 using ABT-199 and HHT, single agent, or in combination, in vitro and in vivo on primary cell-based murine xenograft models of DLBCL.
By the pharmacologic targeting of BCL2, MCL1, and BCL-XL, we demonstrated that DLBCL can be divided into BCL2-dependent and MCL1-dependent subgroups with a less pronounced role left for BCL-XL. Derived DLBCL clones with manipulated expressions of BCL2, MCL1, and BCL-XL, as well as the immunoprecipitation experiments, which analyzed MCL1 protein complexes, confirmed these findings at the molecular level. We demonstrated that concurrent inhibition of BCL2 and MCL1 with ABT-199 and HHT induced significant synthetic lethality in most BCL2-expressing DLBCL cell lines. The marked cytotoxic synergy between ABT-199 and HHT was also confirmed in vivo using primary cell-based murine xenograft models of DLBCL.
As homoharringtonine is a clinically approved antileukemia drug, and ABT-199 is in advanced phases of diverse clinical trials, our data might have direct implications for novel concepts of early clinical trials in patients with aggressive DLBCL.
Partial nitritation-anammox (PN/A) process will substantially reduce the costs for the removal of nitrogen in the mainstream of municipal sewage. However, one of the mainstream PN/A challenges is to ...reduce the time necessary for the adaptation of anammox bacteria to lower temperatures in mild climates. In this study, we exposed anammox flocculent culture to cold shocks 35°C → 5°C (8 h) → 15°C and evaluated long-term cold shock response. Over a post-shock period of 40 d at 15°C, the nitrogen removal rates in the shocked culture were significantly higher compared to control, with maximum rates up to 0.082 and 0.033 kg-N/kg-VSS/d or 0.164 and 0.076 kg-N/m
3
/d, for shocked culture and control, respectively. In the corresponding semi-batch cycles, the shocked culture was on average 136 ± 101% more active than the control, due to the negative effect of cold shock on side populations and more active anammox cells. Per FISH, Ca. Brocadia anammoxidans and Ca. Scalindua survived the shock and remained present throughout. Thus, both anammox microorganisms seem to respond favourably to cold shocks. In sum, we provide further evidence that cold shocks accelerate the adaptation of anammox to the mainstream of municipal WWTPs. Further, for the first time, we report the long-term adaptive response of anammox to cold shocks.
•A lab-scale bio-membrane unit for microaerobic H2S removal from biogas.•H2S removal efficiency of more than 99% during the continuous experiment.•Thiobacillus thioparus identified in the biofilm by ...both FISH and PCR-DGGE.•The permeation of gases though the membranes: H2S>CO2>CH4>O2>N2.
A lab-scale bio-membrane unit was developed to improve H2S removal from biogas through microaeration. Biomembrane separated biogas from air and consisted of a silicone tube covered by microaerobic biofilm. This setup allowed efficient H2S removal while minimizing biogas contamination with oxygen and nitrogen. The transport and removal of H2S, N2, O2, CH4 and CO2 through bare membrane, wet membrane and biomembrane was investigated. Membrane allowed the transfer of gases through it as long as there was enough driving force to induce it. H2S concentration in biogas decreased much faster with the biomembrane. The permeation of gases through the membranes decreased in order: H2S>CO2>CH4>O2>N2. H2S removal efficiency of more than 99% was observed during the continuous experiment. Light yellow deposits on the membrane indicated the possible elemental sulfur formation due to biological oxidation of H2S. Thiobacillus thioparus was detected by FISH and PCR-DGGE.
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