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1. Honey bee (Apis mellifera ligustica) acetylcholinesterase enzyme activity and aversive conditioning following aluminum trichloride exposure

   https://doi.org/10.1186/s40850-021-00103-8  

   Chicas-Mosier, A. M.; Black, T. E.; Hester, K. P.; Belzunces, L. P.; Abramson, C. I. (January 2022, BMC Zoology)

   Abstract BackgroundAluminum is the third most prevalent element in the earth’s crust. In most conditions, it is tightly bound to form inaccessible compounds, however in low soil pH, the ionized form of aluminum can be taken up by plant roots and distributed throughout the plant tissue. Following this uptake, nectar and pollen concentrations in low soil pH regions can reach nearly 300 mg/kg. Inhibition of acetylcholinesterase (AChE) has been demonstrated following aluminum exposure in mammal and aquatic invertebrate species. In honey bees, behaviors consistent with AChE inhibition have been previously recorded; however, the physiological mechanism has not been tested, nor has aversive conditioning. ResultsThis article presents results of ingested aqueous aluminum chloride exposure on AChE as well as acute exposure effects on aversive conditioning in anApis mellifera ligusticahive. Contrary to previous findings, AChE activity significantly increased as compared to controls following exposure to 300 mg/L Al³⁺. In aversive conditioning studies, using an automated shuttlebox, there were time and dose-dependent effects on learning and reduced movement following 75 and 300 mg/L exposures. ConclusionsThese findings, in comparison to previous studies, suggest that aluminum toxicity in honey bees may depend on exposure period, subspecies, and study metrics. Further studies are encouraged at the moderate-high exposure concentrations as there may be multiple variables that affect toxicity which should be teased apart further. 

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2. Evaluation of anammox biocathode in microbial desalination and wastewater treatment

   https://doi.org/https://doi.org/10.1016/j.cej.2018.02.088  

   Bahareh Kokabian, Veera Gnaneswar (June 2018, Chemical engineering journal)

   This study presents the use of an autotrophic microorganism, Anammox bacteria, as a sustainable biocatalyst/biocathode in microbial desalination cells (MDCs) for energy-positive wastewater treatment. We report the first proof of concept study to prove that anammox mechanism can be beneficial in MDCs to provide simultaneous removal of carbon and nitrogen compounds from wastewater while producing bioelectricity. A series of experiments were conducted to enrich and evaluate the anammox mechanism and the process performance in continuous, fed-batch mode conditions. Coulombic efficiency of MDCs and nitrite and ammonium removal of wastewater increased in successive batch studies. A maximum power density of 0.092 Wm−3 (or a maximum current density of 0.814 A m−3) with more than 90% of ammonium removal was achieved in this system. We calculated the Nernst potential for the nitrite reduction in the anammox biocathode chamber and compared with experimental values. Sequential removal of carbon and nitrogen compounds in anode and cathode chambers respectively, was also evaluated. Further, the inhibition effect of high nitrogen concentrations and the variations in microbial community profiles, especially, anammox presence was studied at different carbon and ammonia concentrations. Experimental studies and microbial community analysis are presented in detail. 

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3. Arctic Permafrost Thawing Enhances Sulfide Oxidation

   https://doi.org/10.1029/2022GB007644  

   Kemeny, Preston Cosslett; Li, Gen K.; Douglas, Madison; Berelson, William; Chadwick, Austin J.; Dalleska, Nathan F.; Lamb, Michael P.; Larsen, William; Magyar, John S.; Rollins, Nick E.; et al (November 2023, Global Biogeochemical Cycles)

   Abstract Permafrost degradation is altering biogeochemical processes throughout the Arctic. Thaw‐induced changes in organic matter transformations and mineral weathering reactions are impacting fluxes of inorganic carbon (IC) and alkalinity (ALK) in Arctic rivers. However, the net impact of these changing fluxes on the concentration of carbon dioxide in the atmosphere (pCO₂) is relatively unconstrained. Resolving this uncertainty is important as thaw‐driven changes in the fluxes of IC and ALK could produce feedbacks in the global carbon cycle. Enhanced production of sulfuric acid through sulfide oxidation is particularly poorly quantified despite its potential to remove ALK from the ocean‐atmosphere system and increasepCO₂, producing a positive feedback leading to more warming and permafrost degradation. In this work, we quantified weathering in the Koyukuk River, a major tributary of the Yukon River draining discontinuous permafrost in central Alaska, based on water and sediment samples collected near the village of Huslia in summer 2018. Using measurements of major ion abundances and sulfate () sulfur (³⁴S/³²S) and oxygen (¹⁸O/¹⁶O) isotope ratios, we employed the MEANDIR inversion model to quantify the relative importance of a suite of weathering processes and their net impact onpCO₂. Calculations found that approximately 80% of in mainstem samples derived from sulfide oxidation with the remainder from evaporite dissolution. Moreover,³⁴S/³²S ratios,¹³C/¹²C ratios of dissolved IC, and sulfur X‐ray absorption spectra of mainstem, secondary channel, and floodplain pore fluid and sediment samples revealed modest degrees of microbial sulfate reduction within the floodplain. Weathering fluxes of ALK and IC result in lower values ofpCO₂over timescales shorter than carbonate compensation (∼10⁴ yr) and, for mainstem samples, higher values ofpCO₂over timescales longer than carbonate compensation but shorter than the residence time of marine (∼10⁷ yr). Furthermore, the absolute concentrations of and Mg²⁺in the Koyukuk River, as well as the ratios of and Mg²⁺to other dissolved weathering products, have increased over the past 50 years. Through analogy to similar trends in the Yukon River, we interpret these changes as reflecting enhanced sulfide oxidation due to ongoing exposure of previously frozen sediment and changes in the contributions of shallow and deep flow paths to the active channel. Overall, these findings confirm that sulfide oxidation is a substantial outcome of permafrost degradation and that the sulfur cycle responds to permafrost thaw with a timescale‐dependent feedback on warming. 

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4. Synthesis of 1,2,3-triazole containing compounds as potential antimicrobial agents

   https://doi.org/10.7717/peerj-ochem.10  

   Bezold, Elise L; Kempton, Robert J; Green, Keith D; Hensley, Ramey W; Gilliam, Olivia K; Garneau-Tsodikova, Sylvie; Onorato, Amber J (July 2024, PeerJ Organic Chemistry)

   Invasive fungal infections are increasing worldwide due to an expanding number of immunocompromised patients as well as an increase in drug-resistant fungi. While fungal resistance has increased, this resistance has not been accompanied by the development of new antifungals. A common class of antifungal agents that are prescribed are the azoles, which contain either a triazole or an imidazole group. Unfortunately, current azoles, like fluconazole, have been shown to be less effective with the increase in resistant fungal pathogens. Therefore, the development of novel azole antifungal compounds is of urgent need. The objective of this research was to synthesize triazole-containing small molecules with potent antifungal activity. The scaffold of the synthesized compounds contains a triazole moiety and was synthesized via a copper-catalyzed azide-alkyne click reaction (CuAAC) between the appropriate alkyne and azide intermediates. The minimum inhibitory concentrations of these compounds were determined using standard broth microdilution assays against opportunistic bacteria and fungi associated with life-threatening invasive fungal infections. Although the synthesized compounds possessed no antimicrobial activity, these results can be used to further the long-term goal of developing and optimizing lead compounds with potentin vitroantifungal activity. 

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5. Integration of EBPR with mainstream anammox process to treat real municipal wastewater: Process performance and microbiology

   Hong, S; Winkler, MKH; Wang, Z; Goel, R (February 2023, Water research)

   The mainstream application of anaerobic ammonium oxidation (anammox) for sustainable N removal remains a challenge. Similarly, with recent additional stringent regulations for P discharges, it is imperative to integrate N with P removal. This research studied integrated fixed film activated sludge (IFAS) technology to simultaneously remove N and P in real municipal wastewater by combining biofilm anammox with flocculent activated sludge for enhanced biological P removal (EBPR). This technology was assessed in a sequencing batch reactor (SBR) operated as a conventional A2O (anaerobic-anoxic-oxic) process with a hydraulic retention time of 8.8 h. After a steady state operation was reached, robust reactor performance was obtained with average TIN and P removal efficiencies of 91.3 ± 4.1% and 98.4 ± 2.4%, respectively. The average TIN removal rate recorded over the last 100 d of reactor operation was 118 mg/L⋅d, which is a reasonable number for mainstream applications. The activity of denitrifying polyphosphate accumulating organisms (DPAOs) accounted for nearly 15.9% of P-uptake during the anoxic phase. DPAOs and canonical denitrifiers removed approximately 5.9 mg TIN/L in the anoxic phase. Batch activity assays, which showed that nearly 44.5% of TIN were removed by the biofilms during the aerobic phase. The functional gene expression data also confirmed anammox activities. The IFAS configuration of the SBR allowed operation at a low solid retention time (SRT) of 5-d without washing out biofilm ammoniumoxidizing and anammox bacteria. The low SRT, combined with low dissolved oxygen and intermittent aeration, provided a selective pressure to washout nitrite-oxidizing bacteria and glycogen-accumulating organisms, as relative abundances. 

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