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Journal of Hazardous Materials Sep 2021Azoles are an emerging class of contaminants with a growing ubiquitous presence in the environment. This study investigates the aerobic microbial degradation of four...
Azoles are an emerging class of contaminants with a growing ubiquitous presence in the environment. This study investigates the aerobic microbial degradation of four azoles, pyrazole (PA), 1,2,4-triazole (TA), benzotriazole (BTA) and 5-methylbenzotriazole (5-MBTA), with return activated sludge and microbial enrichment cultures. Slow degradation of PA was observed in the presence of glucose and NH with a peak degradation rate of 0.5 mg d gVSS. TA was found to be highly persistent, with no significant degradation observed in 6-8 months under any incubation condition. In contrast, the benzotriazoles were readily degraded at faster rates in all incubation conditions. The degradation rates observed for BTA and 5-MBTA, when provided as the sole substrates, were 8.1 and 16.5 mg d gVSS, respectively. Two enrichment cultures, one degrading BTA and the other degrading 5-MBTA, were developed from the activated sludge. Mass balance studies revealed complete mineralization of 5-MBTA and partial breakdown of BTA by the enrichment cultures. Nocardioides sp. and Pandoraea pnomenusa were the most abundant bacteria in the BTA and 5-MBTA degrading enrichment cultures, respectively. The research shows large differences in the biodegradability of various azoles, ranging from complete mineralization of 5-MBTA to complete persistence for TA.
Topics: Azoles; Biodegradation, Environmental; Burkholderiaceae; Sewage
PubMed: 34229401
DOI: 10.1016/j.jhazmat.2021.126151 -
The ISME Journal Mar 2021The expanding antibiotic resistance crisis calls for a more in depth understanding of the importance of antimicrobial resistance genes (ARGs) in pristine environments....
The expanding antibiotic resistance crisis calls for a more in depth understanding of the importance of antimicrobial resistance genes (ARGs) in pristine environments. We, therefore, studied the microbiome associated with Sphagnum moss forming the main vegetation in undomesticated, evolutionary old bog ecosystems. In our complementary analysis of culture collections, metagenomic data and a fosmid library from different geographic sites in Europe, we identified a low abundant but highly diverse pool of resistance determinants, which targets an unexpectedly broad range of 29 antibiotics including natural and synthetic compounds. This derives both, from the extraordinarily high abundance of efflux pumps (up to 96%), and the unexpectedly versatile set of ARGs underlying all major resistance mechanisms. Multi-resistance was frequently observed among bacterial isolates, e.g. in Serratia, Rouxiella, Pandoraea, Paraburkholderia and Pseudomonas. In a search for novel ARGs, we identified the new class A β-lactamase Mm3. The native Sphagnum resistome comprising a highly diversified and partially novel set of ARGs contributes to the bog ecosystem´s plasticity. Our results reinforce the ecological link between natural and clinically relevant resistomes and thereby shed light onto this link from the aspect of pristine plants. Moreover, they underline that diverse resistomes are an intrinsic characteristic of plant-associated microbial communities, they naturally harbour many resistances including genes with potential clinical relevance.
Topics: Anti-Bacterial Agents; Drug Resistance, Microbial; Europe; Genes, Bacterial; Metagenome; Wetlands
PubMed: 33177608
DOI: 10.1038/s41396-020-00822-9 -
Chemosphere Dec 2021Soil amendment is a promising strategy to enhance biodegradation capacity of indigenous bacteria. To assess the consequences of various soil amendments before...
Soil amendment is a promising strategy to enhance biodegradation capacity of indigenous bacteria. To assess the consequences of various soil amendments before large-scale implementation, a microcosm study was employed to investigate the effects of nutrients (TN), surfactants (TS), oxidants (TO), biochar (TB), and zero-valent iron nanoparticles (nZVI; TNP) on diesel degradation, bacterial communities, and community-level physiological profiles (CLPPs) of legacy field contaminated soil. The results showed that the TN, TB, TNP, TS, and TO, reduced 75.8%, 63.9%, 62.8%, 49.3%, and 40.1% of total petroleum hydrocarbons (TPH), respectively, within 120 days, while control (TW) reduced only 33.8%. In all soil amendments, TPH reduction was positively correlated with oxidation-reduction potential and heterotrophic and TPH-degrading bacteria, while negatively correlated with total nitrogen and available phosphate. Furthermore, in TW, TB, and TNP microcosms, TPH reduction showed positive association with pH, whereas in TN, TS, and TO, TPH reduction was negatively associated with pH. The bacterial diversity was reduced in all treatments as a function of the soil amendment and remediation time: the enriched potential TPH-degrading bacteria were Dyella, Paraburkholderia, Clavibacter, Arthrobacter, Rhodanobacter, Methylobacterium, and Pandoraea. The average well colour development (AWCD) values in CLPPs were higher in TB, sustained and improved in TN, and markedly lower in TNP, TS, and TO microcosms. Overall, these data demonstrate that nutrients and biochar amendments may be helpful in boosting biodegradation, increasing diesel-degrading bacteria, and improving soil physiological functions. In conclusion, diesel degradation efficiency and bacterial communities are widely affected by both type and duration of soil amendments.
Topics: Bacteria; Biodegradation, Environmental; Hydrocarbons; Petroleum; Soil; Soil Microbiology; Soil Pollutants
PubMed: 34242986
DOI: 10.1016/j.chemosphere.2021.131416 -
Bulletin of Environmental Contamination... Oct 2019The widespread use of bisphenol S (BPS) as a bisphenol A substitute increases its potential of release into the aquatic environments. However, the degradation of BPS in...
The widespread use of bisphenol S (BPS) as a bisphenol A substitute increases its potential of release into the aquatic environments. However, the degradation of BPS in aquatic systems is largely unknown, which will dictate its fate and toxicity. In this study, a bacterial consortium was enriched from river sediments and the dynamic changes of community structure during bacterial acclimation were studied. BPS degrading bacterial strains isolated from the consortium were identified by 16S rRNA analysis. The efficiency of the consortium and strains for BPS degradation were further evaluated. After 28 days of acclimation, the microbial diversity decreased significantly and four bacterial genera Hyphomicrobium, Pandoraea, Rhodococcus, and Cupriavidus with relative abundances of 5.1%-52.8% became dominant in the consortium. Total of two pure strains including Terrimonas pekingensis and Pseudomonas sp. were isolated from the consortium, using BPS as the sole carbon source. The consortium was highly efficient to degrade BPS, and 99% of BPS with an initial concentration of 50 mg/L was removed within 10 days at pH 7 and 30°C. In comparison with the consortium, a single strain cultures had lower BPS degradation efficiency. These findings indicate that BPS will degrade rapidly under aerobic conditions in river sediments and have implication for BPS-contaminated site remediation using the enriched consortium.
Topics: Bacteria; Benzhydryl Compounds; Biodegradation, Environmental; Geologic Sediments; Microbial Consortia; Phenols; Pseudomonas; RNA, Ribosomal, 16S; Rhodococcus; Rivers; Sulfones
PubMed: 31486911
DOI: 10.1007/s00128-019-02699-7 -
ACS Central Science Jul 2022Dynamics is an essential process to drive an enzyme to perform a function. When a protein sequence encodes for its three-dimensional structure and hence its function, it...
Dynamics is an essential process to drive an enzyme to perform a function. When a protein sequence encodes for its three-dimensional structure and hence its function, it essentially defines the intrinsic dynamics of the molecule. The static X-ray crystal structure was thought to shed little insight into the molecule's dynamics until the recently available tool "Ensemble refinement" (ER). Here, we report the structure-function-dynamics of PanPL, an alginate-specific, endolytic, allosteric polysaccharide lyase belonging to the PL-5 family from . The crystal structures determined in apo and tetra-ManA bound forms reveal that the PanPL maintains a closed state with an N-terminal loop lid (N-loop-lid) arched over the active site. The B-factor analyses and ER congruently reveal how pH influences the functionally relevant atomic fluctuations at the N-loop-lid. The ER unveils enhanced fluctuations at the N-loop-lid upon substrate binding. The normal-mode analysis finds that the functional states are confined. The 1 μs simulation study suggests the existence of a hidden open state. The longer N-loop-lid selects a mechanism to adopt a closed state and undergo fluctuations to facilitate the substrate binding. Here, our work demonstrates the distinct modes of dynamics; both intrinsic and substrate-induced conformational changes are vital for enzyme functioning and allostery.
PubMed: 35912344
DOI: 10.1021/acscentsci.2c00277 -
Microorganisms Feb 2020As an environmental pollutant, tetracycline (TC) can persist in the soil for years and damage the ecosystem. So far, many methods have been developed to handle the TC...
As an environmental pollutant, tetracycline (TC) can persist in the soil for years and damage the ecosystem. So far, many methods have been developed to handle the TC contamination. Microbial remediation, which involves the use of microbes to biodegrade the pollutant, is considered cost-efficient and more suitable for practical application in soil. This study isolated several strains from TC-contaminated soil and constructed a TC-degrading bacterial consortium containing sp. XY-1 and sp. XY-2, which exhibited better growth and improved TC degradation efficiency compared with single strain (81.72% TC was biodegraded within 12 days in Lysogeny broth (LB) medium). Subsequently, lab-scale soil remediation was conducted to evaluate its effectiveness in different soils and the environmental effects it brought. Results indicated that the most efficient TC degradation was recorded at 30 °C and in soil sample Y which had relatively low initial TC concentration (around 35 mg/kg): TC concentration decreased by 43.72% within 65 days. Soil properties were affected, for instance, at 30 °C, the pH value of soil sample Y increased to near neutral, and soil moisture content (SMC) of both soils declined. Analysis of bacterial communities at the phylum level showed that , , , and were the four dominant phyla, and the relative abundance of significantly increased in both soils after bioremediation. Further analysis of bacterial communities at the genus level revealed that sp. XY-1 successfully proliferated in soil, while sp. XY-2 was undetectable. Moreover, bacteria associated with nitrogen cycling, biodegradation of organic pollutants, soil biochemical reactions, and plant growth were affected, causing the decline in soil bacterial diversity. Variations in the relative abundance of tetracycline resistance genes (TRGs) and mobile gene elements (MGEs) were investigated, the results obtained indicated that , , , , and had higher relative abundance in original soils, and the relative abundance of most TRGs and MGEs declined after the microbial remediation. Network analysis indicated that may dominate the transfer of TRGs, and , , , , , and were possible hosts of TRGs or MGEs. This study comprehensively evaluated the effectiveness and the ecological effects of the TC-degrading bacterial consortium in soil environment.
PubMed: 32093355
DOI: 10.3390/microorganisms8020292 -
Journal of Cardiology Cases Jul 2021Late prosthetic valve endocarditis (PVE) is a life-threatening condition, commonly caused by bacterial organisms such as staphylococci, streptococci, or enterococci....
Late prosthetic valve endocarditis (PVE) is a life-threatening condition, commonly caused by bacterial organisms such as staphylococci, streptococci, or enterococci. Infrequently, it can be caused by rare organisms. We hereby report a case of late PVE of the aortic valve, due to a rare gram-negative bacterium It is the first reported case of PVE caused by this particular organism. The patient had infective endocarditis-induced prosthetic valve dehiscence, severe aortic regurgitation, and shock, which was managed with appropriate antibiotics and supportive medical treatment. < Late prosthetic valve infective endocarditis should always be an important differential diagnosis in patients with artificial valve presenting with congestive cardiac failure. This case report is about aortic valve dehiscence and acute aortic regurgitation because of prosthetic valve infective endocarditis due to a rare bacterium .
PubMed: 34257757
DOI: 10.1016/j.jccase.2020.12.003 -
Surgical Neurology International 2021is predominantly recovered from the respiratory tract of patients with cystic fibrosis (CF). Authors report first case of central nervous system infection by in the...
BACKGROUND
is predominantly recovered from the respiratory tract of patients with cystic fibrosis (CF). Authors report first case of central nervous system infection by in the form of skull base osteomyelitis.
CASE DESCRIPTION
A 67-year-old male presented with complaints of earache and hearing deficit for few months. The radiology was suggestive of skull base osteomyelitis and polypoidal soft tissue extending from the middle cranial fossa to the infratemporal fossa. The sample from the targeted area revealed on matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. With adequate antibiotic therapy, there was clinicoradiologic improvement. is an infection exclusively seen in pulmonary infection in patients with CF. We identified its intracranial involvement in a patient for the 1 time in the literature. The serendipitous diagnosis needs evaluation on specific PCR and matrix-assisted laser desorption spectrometry. The treatment with antibiotics provides a definite cure.
CONCLUSION
We report a rare opportunistic infection with central nervous system involvement which can be cured by accurate diagnosis and appropriate antibiotic treatment.
PubMed: 34621562
DOI: 10.25259/SNI_472_2021 -
Current Biology : CB Jul 2023The stability of endosymbiotic associations between eukaryotes and bacteria depends on a reliable mechanism ensuring vertical inheritance of the latter. Here, we...
The stability of endosymbiotic associations between eukaryotes and bacteria depends on a reliable mechanism ensuring vertical inheritance of the latter. Here, we demonstrate that a host-encoded protein, located at the interface between the endoplasmic reticulum of the trypanosomatid Novymonas esmeraldas and its endosymbiotic bacterium Ca. Pandoraea novymonadis, regulates such a process. This protein, named TMP18e, is a product of duplication and neo-functionalization of the ubiquitous transmembrane protein 18 (TMEM18). Its expression level is increased at the proliferative stage of the host life cycle correlating with the confinement of bacteria to the nuclear vicinity. This is important for the proper segregation of bacteria into the daughter host cells as evidenced from the TMP18e ablation, which disrupts the nucleus-endosymbiont association and leads to greater variability of bacterial cell numbers, including an elevated proportion of aposymbiotic cells. Thus, we conclude that TMP18e is necessary for the reliable vertical inheritance of endosymbionts.
Topics: Trypanosomatina; Bacteria; Symbiosis; Eukaryota
PubMed: 37201521
DOI: 10.1016/j.cub.2023.04.060 -
Antibiotics (Basel, Switzerland) Feb 2022Alternative strategies against multidrug-resistant (MDR) bacterial infections are suggested to clinicians, such as drug repurposing, which uses rapidly available and...
Alternative strategies against multidrug-resistant (MDR) bacterial infections are suggested to clinicians, such as drug repurposing, which uses rapidly available and marketed drugs. We gathered a collection of MDR bacteria from our hospital and performed a phenotypic high-throughput screening with a 1280 FDA-approved drug library. We used two Gram positive (Enterococcus faecium P5014 and Staphylococcus aureus P1943) and six Gram negative (Acinetobacter baumannii P1887, Klebsiella pneumoniae P9495, Pseudomonas aeruginosa P6540, Burkholderia multivorans P6539, Pandoraea nosoerga P8103, and Escherichia coli DSM105182 as the reference and control strain). The selected MDR strain panel carried resistance genes or displayed phenotypic resistance to last-line therapies such as carbapenems, vancomycin, or colistin. A total of 107 compounds from nine therapeutic classes inhibited >90% of the growth of the selected Gram negative and Gram positive bacteria at a drug concentration set at 10 µmol/L, and 7.5% were anticancer drugs. The common hit was the antiseptic chlorhexidine. The activity of niclosamide, carmofur, and auranofin was found against the selected methicillin-resistant S. aureus. Zidovudine was effective against colistin-resistant E. coli and carbapenem-resistant K. pneumoniae. Trifluridine, an antiviral, was effective against E. faecium. Deferoxamine mesylate inhibited the growth of XDR P. nosoerga. Drug repurposing by an in vitro screening of a drug library is a promising approach to identify effective drugs for specific bacteria.
PubMed: 35326755
DOI: 10.3390/antibiotics11030291