Assessment of Mitochondrial Function in the AmE-711 Honey Bee Cell Line: Boscalid and Pyraclostrobin Effects.

There is a growing concern that chronic exposure to fungicides contributes to negative effects on honey bee development, life span, and behavior. Field and caged-bee studies have helped to characterize the adverse outcomes (AOs) of environmentally relevant exposures, but linking AOs to molecular/cellular mechanisms of toxicity would benefit from the use of readily controllable, simplified host platforms like cell lines. Our objective was to develop and optimize an in vitro-based mitochondrial toxicity assay suite using the honey bee as a model pollinator, and the electron transport chain (ETC) modulators boscalid and pyraclostrobin as model fungicides. We measured the effects of short (~30 min) and extended exposures (16-24 h) to boscalid and pyraclostrobin on AmE-711 honey bee cell viability and mitochondrial function. Short exposure to pyraclostrobin did not affect cell viability, but extended exposure reduced viability in a concentration-dependent manner (median lethal concentration = 4175 µg/L; ppb). Mitochondrial membrane potential (MMP) was affected by pyraclostrobin in both short (median effect concentration [EC50] = 515 µg/L) and extended exposure (EC50 = 982 µg/L) scenarios. Short exposure to 10 and 1000 µg/L pyraclostrobin resulted in a rapid decrease in the oxygen consumption rate (OCR), approximately 24% reduction by 10 µg/L relative to the baseline OCR, and 64% by 1000 µg/L. Extended exposure to 1000 µg/L pyraclostrobin reduced all respiratory parameters (e.g., spare capacity, coupling efficiency), whereas 1- and 10-µg/L treatments had no significant effects. The viability of AmE-711 cells, as well as the MMP and cellular respiration were unaffected by short and extended exposures to boscalid. The present study demonstrates that the AmE-711-based assessment of viability, MMP, and ETC functionality can provide a time- and cost-effective platform for mitochondrial toxicity screening relevant to bees. Environ Toxicol Chem 2024;43:976-987. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Impact of COVID-19 on patterns of drug utilization: A case study at national hospital.

BACKGROUND: The Coronavirus disease of 2019 (COVID-19) pandemic and the corresponding mitigation measures have had a discernible impact on drug utilization among outpatients. However, limited research exists on the prescription trends in the elderly population during the pandemic period in Viet Nam. OBJECTIVES: This study aims to analyze the effects of COVID-19 on outpatient drug utilization patterns at a national geriatric hospital in Ho Chi Minh City before and after the early onset of the pandemic. METHODS: Data was collected from the prescriptions and administration claims, encompassing the period from January 2016 to December 2022. The dataset was divided into two periods: Period 1: January 2016 to December 2020 and Period 2: January 2021 to December 2022. The drug utilization was measured using DDD/1000P (defined daily doses-DDD per 1000 prescriptions) on a monthly basis. The analysis employed interrupted time series using Autoregressive Integrated Moving Average (ARIMA) to detect changes in drug use levels and rates. RESULTS: A total of 1,060,507 and 644,944 outpatient prescriptions from Thong Nhat Hospital were included in Period 1 and Period 2, respectively. The median age of the patients were 58 in Period 1 and 67 years old in Period 2. The most common comorbidities were dyslipidemia, hypertension, and diabetes mellitus. In terms of medication utilization, cardiovascular drugs were the most frequently prescribed, followed by drugs active on the digestive and hormonal systems. The study observed significant surges in the number of prescriptions and the average number of drugs per prescription. However, there were no significant changes in the overall consumption of all drugs. Among the drug groups related to the cardiovascular system, three subgroups experienced a sudden and significant increase: cardiac therapy, beta-blocking agents, and antihypertensives, with increasing consumption levels of 1,177.73 [CI 95%: 79.29; 2,276.16], 73.32 [CI 95%: 28.18; 118.46], and 36.70 [CI 95%: 6.74; 66.66] DDD/1000P, respectively. On the other hand, there was a significant monthly decrease of -31.36 [CI 95%: -57.02; -5.70] DDD/1000P in the consumption of anti-inflammatory and antirheumatic products. Interestingly, there was a significant increase of 74.62 [CI 95%: -0.36; 149.60] DDD/1000P in the use of antigout preparations. CONCLUSION: COVID-19 resulted in a sudden, non-significant increase in overall drug consumption levels among outpatients. Notably, our findings highlight significant increases in the utilization of three drug groups related to the cardiovascular system, specifically cardiac therapy, beta-blocking agents, and antihypertensives. Intriguingly, there was a statistically significant increase in the consumption of antigout preparations, despite a decline in the monthly consumption rate of non-steroidal anti-flammatory drugs (NSAIDs). Further studies in the following years are necessary to provide a more comprehensive understanding of the impact of COVID-19 on outpatient drug utilization patterns.

Evidence that the catalytic mechanism of heme a synthase involves the formation of a carbocation stabilized by a conserved glutamate.

In eukaryotes and many aerobic prokaryotes, the final step of aerobic respiration is catalyzed by an aa3-type cytochrome c oxidase, which requires a modified heme cofactor, heme a. The conversion of heme b, the prototypical cellular heme, to heme o and ultimately to heme a requires two modifications, the latter of which is conversion of a methyl group to an aldehyde, catalyzed by heme a synthase (HAS). The N- and C-terminal halves of HAS share homology, and each half contains a heme-binding site. Previous reports indicate that the C-terminal site is occupied by a heme b cofactor. The N-terminal site may function as the substrate (heme o) binding site, although this has not been confirmed experimentally. Here, we assess the role of conserved residues from the N- and C-terminal heme-binding sites in HAS from prokaryotic (Shewanella oneidensis) and eukaryotic (Saccharomyces cerevisiae) species - SoHAS/CtaA and ScHAS/Cox15, respectively. A glutamate within the N-terminal site is found to be critical for activity in both types of HAS, consistent with the hypothesis that a carbocation forms transiently during catalysis. In contrast, the residue occupying the analogous C-terminal position is dispensable for enzyme activity. In SoHAS, the C-terminal heme ligands are critical for stability, while in ScHAS, substitutions in either heme-binding site have little effect on global structure. In both species, in vivo accumulation of heme o requires the presence of an inactive HAS variant, highlighting a potential regulatory role for HAS in heme o biosynthesis.