GO:0015904 tetracycline transmembrane transport: Antibiotic Efflux Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0015904 (tetracycline transmembrane transport) describes the directed movement of tetracycline, a broad-spectrum antibiotic that blocks aminoacyl-tRNA binding to ribosomes, across a membrane [QuickGO definition].
• The best-characterized molecular machines for this process are the TetA family antiporters, including TetA(B) from Tn10 and Tet(L), which exchange tetracycline for a proton or monovalent cation.
• Transmembrane helices 3, 4, 5, 7 and 8 of TetA(B) form a substrate translocation pathway; residues such as Asp-84, Ser-65/67/68, Glu-397 and Gln-225 are essential for tetracycline transport.
• Loss-of-function mutations in the 14-transmembrane-segment Tet(L) protein (e.g., DeltaTMS VII-VIII) abolish tetracycline efflux while retaining monovalent cation transport, demonstrating that these activities are genetically separable.
• Tetracycline transport proteins are clinically important because they mediate antibiotic resistance in Gram-positive and Gram-negative bacteria and are increasingly studied as targets for efflux-pump inhibitors.
• EDITGENE provides CRISPR knockout, point-mutation, knock-in, overexpression cell models and CRISPR library screening/bioinformatics services to dissect tetracycline transport genes in a publication-ready format.
Description
Tetracycline transmembrane transport (GO:0015904) is the biological process by which the broad-spectrum antibiotic tetracycline is moved from one side of a membrane to the other [QuickGO definition]. Tetracycline blocks binding of aminoacyl tRNA to the ribosomes of both Gram-positive and Gram-negative organisms, and the directed transport of this drug across membranes is therefore a central determinant of its intracellular concentration and antibacterial activity [QuickGO definition]. In bacteria, the most extensively studied systems that carry out this process are the TetA family antiporters, which couple tetracycline efflux to the inward movement of a proton or a monovalent cation. The Tn10-encoded TetA(B) protein of Escherichia coli and the Tet(L) protein of Gram-positive bacteria are the archetypal members of this family, and decades of mutagenesis and biochemical work have mapped the residues and transmembrane segments that form their substrate translocation pathway. Understanding GO:0015904 is important not only for antibiotic resistance biology but also for drug discovery, because efflux-mediated tetracycline transport directly reduces the effective intracellular concentration of the drug and contributes to treatment failure. In this article we integrate the QuickGO definition with verified PubMed literature to describe the mechanism, key genes, disease relevance and experimental models for studying tetracycline transmembrane transport.
tetracycline transmembrane transport At A Glance
| GO ID | GO:0015904 |
|---|---|
| GO term | tetracycline transmembrane transport |
| Ontology | biological_process |
| Synonym | tetracycline transport; tetracyclin transport |
| Definition | The directed movement of tetracycline from one side of a membrane to the other; tetracycline is a broad spectrum antibiotic that blocks binding of aminoacyl tRNA to the ribosomes of both Gram-positive and Gram-negative organisms (and those of organelles). |
| Major function | Membrane translocation of tetracycline, often coupled to proton or monovalent cation antiport, mediating antibiotic efflux and resistance. |
| Representative proteins | TetA(B) (Tn10), Tet(L), TetA family antiporters. |
| Cellular context | Bacterial inner membrane; also relevant to organelle ribosome-targeting antibiotics [QuickGO definition]. |
| Research relevance | Antibiotic resistance mechanisms, efflux pump inhibitor discovery, membrane protein structure-function studies. |
What Is GO:0015904?
In our own words, GO:0015904 (tetracycline transmembrane transport) is the directed, membrane-spanning movement of tetracycline from one side of a lipid bilayer to the other. The term is a biological_process in the Gene Ontology and is synonymous with tetracycline transport and tetracyclin transport. The substrate is tetracycline, a broad-spectrum antibiotic that blocks binding of aminoacyl tRNA to the ribosomes of both Gram-positive and Gram-negative organisms (and those of organelles). The process is typically mediated by integral membrane proteins that couple tetracycline movement to an electrochemical gradient, as exemplified by the metal-tetracycline/H+ antiporters of the TetA family.
Why Is tetracycline transmembrane transport Important in Cell Biology?
Tetracycline transmembrane transport is important because it directly controls the intracellular concentration of a clinically widely used antibiotic and is a principal mechanism of bacterial resistance to tetracyclines. The TetA family antiporters that carry out this process are among the best-characterized membrane transport proteins, and their study has provided fundamental insights into how membrane proteins couple substrate movement to ion gradients. Because tetracycline efflux reduces drug efficacy, understanding GO:0015904 is essential for developing efflux-pump inhibitors, optimizing antibiotic dosing, and predicting resistance emergence in Gram-positive and Gram-negative pathogens.
• Tetracycline transmembrane transport determines the intracellular concentration of tetracycline and thus its ability to block aminoacyl-tRNA binding to ribosomes [QuickGO definition].
• TetA family antiporters such as TetA(B) and Tet(L) are the primary molecular machines that carry out this process and are paradigms for membrane transport.
• Residues in transmembrane helices 3, 4, 5, 7 and 8 form the substrate translocation pathway, making this process a model for structure-function studies.
• Loss-of-function mutations can uncouple tetracycline efflux from monovalent cation transport, showing that the two activities are genetically separable.
• Tetracycline transport is a major mechanism of antibiotic resistance in both Gram-positive and Gram-negative bacteria.
• Efflux-mediated tetracycline transport is a validated target for efflux-pump inhibitor development.
• Environmental antibiotic pollution can influence microbial processes such as methylmercury production, linking tetracycline transport biology to ecosystem health.
• Drug-induced fatty liver disease research highlights the need to understand how antibiotics and their transport affect host metabolism.
• CRISPR-based models of transport genes enable causal testing of resistance and transport hypotheses.
• Studying GO:0015904 supports the development of new tetracycline derivatives that evade efflux.
What Happens During tetracycline transmembrane transport?
Substrate recognition and binding
In simple terms: The transporter first grabs the tetracycline molecule at a specific site on the membrane protein.
Tetracycline transmembrane transport begins with substrate recognition by the transporter. In the Tn10-encoded TetA(B) antiporter, Fe(2+)-tetracycline-mediated cleavage experiments identified a substrate binding site near glutamine 225 in transmembrane helix 7, indicating that this region directly contacts the drug. Cysteine-scanning mutagenesis of transmembrane segments 4 and 5 revealed a permeability barrier in the middle of a transmembrane water-filled channel, suggesting that the substrate enters a defined pathway within the protein. These findings establish that tetracycline binding is not random but occurs at discrete residues within the transmembrane domain.
Conformational changes and proton/cation coupling
In simple terms: After binding the drug, the protein changes shape and uses a proton or metal ion as a counter-substrate to push tetracycline across.
The TetA family antiporters couple tetracycline efflux to the inward movement of a proton or a monovalent cation. Serine residues on a vertical stripe including Asp-84 on one side of transmembrane helix 3 are responsible for tetracycline transport in the Tn10-encoded tetracycline/H+ antiporter of Escherichia coli. Transmembrane glutamic acid residues play essential roles in the metal-tetracycline/H+ antiporter of Staphylococcus aureus, indicating that acidic residues are critical for coupling ion movement to drug transport. The 12-transmembrane-segment version (DeltaTMS VII-VIII) of the 14-TMS Tet(L) protein retains monovalent cation transport modes but lacks tetracycline efflux capacity, demonstrating that cation translocation and tetracycline transport can be uncoupled.
Translocation across the membrane
In simple terms: The drug is moved through a channel-like pathway from one side of the membrane to the other.
Once bound and coupled to the ion gradient, tetracycline is translocated across the membrane through a pathway formed by multiple transmembrane helices. Cysteine-scanning mutagenesis of transmembrane segments 4 and 5 of the Tn10-encoded metal-tetracycline/H+ antiporter revealed a permeability barrier in the middle of a transmembrane water-filled channel, consistent with a channel-like translocation route. Transport-defective substrate-binding mutants of TetA(B) have been isolated, providing direct evidence that substrate binding and subsequent translocation are separable steps. Together, these studies show that tetracycline transmembrane transport proceeds through a defined proteinaceous pathway rather than by simple diffusion.
Release and resetting of the transporter
In simple terms: After delivering the drug, the protein returns to its starting shape so it can transport another molecule.
Following translocation, tetracycline is released on the opposite side of the membrane and the transporter resets for another cycle. The identification of transport-defective substrate-binding mutants of TetA(B) indicates that release and resetting are genetically distinct from initial substrate binding. The DeltaTMS VII-VIII Tet(L) variant, which lacks tetracycline efflux capacity but retains monovalent cation transport, further supports a model in which the tetracycline release pathway can be selectively disrupted without abolishing ion transport. These observations are consistent with an alternating-access mechanism in which the protein cycles between inward- and outward-facing conformations.
Physiological consequences of transport
In simple terms: Moving tetracycline out of the cell lowers the drug concentration inside, so ribosomes are protected.
The physiological consequence of tetracycline transmembrane transport is a reduction in intracellular tetracycline concentration, which protects ribosomes from the antibiotic's block of aminoacyl-tRNA binding [QuickGO definition]. Because tetracycline is a broad-spectrum antibiotic active against both Gram-positive and Gram-negative organisms, efficient transport directly determines resistance levels. Antibiotic pollution in the environment can also influence microbial processes such as methylmercury production, linking tetracycline transport biology to broader ecological outcomes. In clinical contexts, drug-induced fatty liver disease research underscores the importance of understanding how antibiotics and their transport affect host tissues.
Key Genes Involved in GO:0015904 tetracycline transmembrane transport
The following genes and proteins are the best-characterized molecular players in tetracycline transmembrane transport (GO:0015904), based on verified PubMed literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| tetA(B) (Tn10) | Tetracycline/H+ antiporter that exports tetracycline across the inner membrane | Archetypal model for structure-function studies of tetracycline transport |
| tetA (Tn10) Asp-84 region | Transmembrane helix 3 residue essential for tetracycline transport | Mutagenesis target for uncoupling transport from cation movement |
| tetA (Tn10) Ser-65/67/68 | Serine residues on a vertical stripe required for tetracycline transport | Defines substrate translocation pathway |
| tetA (Tn10) Gln-225 | Substrate binding site in transmembrane helix 7 | Fe(2+)-tetracycline cleavage mapping of drug binding |
| tetA (Tn10) TMS 4 and 5 | Form a permeability barrier in the middle of a transmembrane water-filled channel | Cysteine-scanning mutagenesis to map the transport channel |
| tetA (Staphylococcus aureus) Glu residues | Transmembrane glutamic acid residues essential for metal-tetracycline/H+ antiport | Acidic residue requirement for coupled transport |
| tet(L) | 14-transmembrane-segment tetracycline efflux protein | DeltaTMS VII-VIII variant separates cation transport from tetracycline efflux |
| tet(L) DeltaTMS VII-VIII | 12-TMS version retaining monovalent cation transport but lacking tetracycline efflux | Demonstrates genetic separability of transport modes |
| TetA(B) substrate-binding mutants | Transport-defective mutants with altered substrate binding | Isolation and characterization of binding-defective antiporters |
| TetA(B) wild-type | Metal-tetracycline/H+ antiporter | Reference for transport assays and inhibitor studies |
| TetA family antiporters (general) | Couple tetracycline efflux to proton or monovalent cation influx | Targets for efflux-pump inhibitor development |
| Ribosomal aminoacyl-tRNA site | Tetracycline target whose binding is blocked by the drug | Physiological rationale for transport-mediated resistance [QuickGO definition] |
| Bacterial inner membrane | Site of tetracycline transmembrane transport | Membrane protein biochemistry and structural studies |
| Efflux pump regulators (general) | Modulate expression of tetracycline transport proteins | Antibiotic resistance regulation |
| Environmental microbial community genes | Contribute to tetracycline transport in polluted niches | Link to methylmercury production and ecosystem health |
| Host metabolic genes (e.g., in DIFLD) | Modify drug-induced fatty liver disease outcomes | Clinical and biochemical analysis of antibiotic effects |
How Is tetracycline transmembrane transport Regulated?
Tetracycline transmembrane transport is regulated at multiple levels. In bacteria, expression of TetA family antiporters is often controlled by tetracycline-responsive regulatory elements, so that transport capacity increases when the drug is present. At the protein level, transport activity depends on the proton or monovalent cation gradient across the membrane, and mutations that alter ion coupling can abolish tetracycline efflux while leaving cation transport intact. Substrate-binding mutants of TetA(B) further show that transport can be regulated by changes in the substrate binding site itself. Environmental factors such as antibiotic pollution can also influence microbial transport and associated processes like methylmercury production. In host tissues, drug-induced fatty liver disease research highlights that antibiotic exposure and transport can interact with metabolic pathways.
tetracycline transmembrane transport and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| tetA(B) | Tetracycline resistance in Gram-negative bacteria | CRISPR knockout of tetA(B) in E. coli; transport assays |
| tet(L) | Tetracycline resistance in Gram-positive bacteria | Point mutations in tet(L) to uncouple cation and drug transport |
| tetA (S. aureus) Glu residues | Metal-tetracycline/H+ antiport and resistance | Site-directed mutagenesis and complementation |
| Host metabolic genes (DIFLD context) | Drug-induced fatty liver disease | Hepatocyte models with CRISPR knockout of candidate metabolic genes |
| Environmental microbial community genes | Antibiotic pollution and methylmercury production | Microcosm experiments with tetracycline exposure |
Antibiotic resistance in bacterial infections
Tetracycline transmembrane transport is a principal mechanism of bacterial resistance to tetracyclines. TetA family antiporters such as TetA(B) and Tet(L) export the drug from the cell, reducing its intracellular concentration and protecting ribosomes from the block of aminoacyl-tRNA binding. Transport-defective mutants of TetA(B) have been isolated, providing direct evidence that substrate binding and translocation are required for resistance. Because these transporters are found in both Gram-positive and Gram-negative organisms, they are high-priority targets for efflux-pump inhibitor development.
Drug-induced fatty liver disease (DIFLD)
Drug-induced fatty liver disease is a clinical syndrome in which medications, including antibiotics, contribute to hepatic steatosis and injury. A comprehensive analysis of clinical, biochemical, and histopathological data has been performed to identify mechanisms and assess consistency with current adverse outcome pathways. Although tetracycline transmembrane transport is primarily a bacterial process, understanding how tetracycline and related drugs are handled by host cells is relevant to DIFLD mechanisms.
Environmental antibiotic pollution and microbial ecology
Antibiotic pollution can elevate microbial methylmercury production, linking tetracycline transport biology to environmental health. Because tetracycline transmembrane transport influences microbial fitness and community composition, environmental reservoirs of tetracycline transport genes may affect biogeochemical cycling. This has implications for understanding how antibiotic resistance and pollutant transformation intersect in natural and engineered ecosystems.
From tetracycline transmembrane transport-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is tetA(B) required for tetracycline efflux? | CRISPR knockout of tetA(B) in E. coli followed by MIC and transport assays |
| Which residues are essential for tetracycline transport? | Point mutations at Asp-84, Ser-65/67/68, Gln-225 or Glu residues |
| Can cation transport be separated from tetracycline efflux? | Knock-in of DeltaTMS VII-VIII Tet(L) variant |
| Where is the substrate binding site? | Tagged knock-in of TetA(B) for Fe(2+)-tetracycline cleavage mapping |
| Does overexpression of TetA increase resistance? | Overexpression of tetA(B) or tet(L) in bacterial hosts |
| Can efflux-pump inhibitors restore tetracycline sensitivity? | CRISPR knockout of efflux genes combined with inhibitor treatment |
How to Study the tetracycline transmembrane transport Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radiolabeled tetracycline transport assay | Accumulation or efflux of tetracycline | Direct measurement of GO:0015904 activity |
| Cysteine-scanning mutagenesis | Accessibility of residues in the transport channel | Mapping the permeability barrier in TMS 4 and 5 |
| Fe(2+)-tetracycline cleavage | Substrate binding site location | Identifying Gln-225 in TMS 7 |
| Site-directed mutagenesis | Role of specific residues in transport | Testing Asp-84, Ser residues, Glu residues |
| MIC and growth assays | Resistance level conferred by transporters | Phenotyping wild-type vs mutant strains |
| Membrane vesicle transport | Ion-coupled transport activity | Studying proton/cation coupling |
| CRISPR knockout screening | Gene requirement for transport | Identifying novel transport genes |
| Bioinformatics and structural modeling | Predicted transmembrane topology and binding pockets | Prioritizing residues for mutagenesis |
Transport assays with radiolabeled or fluorescent tetracycline
Direct measurement of tetracycline transmembrane transport is typically performed using radiolabeled or fluorescent tetracycline derivatives in intact cells or membrane vesicles. These assays quantify the accumulation or efflux of the drug and are the gold standard for testing whether a candidate gene mediates GO:0015904. Mutants such as transport-defective TetA(B) variants are used as negative controls.
Site-directed and cysteine-scanning mutagenesis
Cysteine-scanning mutagenesis of transmembrane segments 4 and 5 of the Tn10-encoded metal-tetracycline/H+ antiporter revealed a permeability barrier in the middle of a transmembrane water-filled channel. Serine and aspartate residues on transmembrane helix 3 were shown to be responsible for tetracycline transport. These approaches map the residues that form the substrate pathway and are essential for mechanistic studies of GO:0015904.
Fe(2+)-tetracycline-mediated cleavage mapping
Fe(2+)-tetracycline-mediated cleavage of the Tn10 tetracycline efflux protein TetA identified a substrate binding site near glutamine 225 in transmembrane helix 7. This chemical cleavage method provides residue-level information about where tetracycline binds within the transporter and complements genetic and biochemical approaches.
Microbiological and resistance phenotyping
Minimum inhibitory concentration (MIC) assays and growth competition experiments are used to link tetracycline transmembrane transport to resistance phenotypes. Strains carrying wild-type or mutant transporters are compared to determine the contribution of specific residues or domains to drug efflux. These methods are widely used to validate CRISPR-generated models of transport genes.
How CRISPR Can Be Used to Study GO:0015904 tetracycline transmembrane transport
Knockout
CRISPR knockout of candidate tetracycline transport genes, such as tetA(B) or tet(L), is used to test whether the gene is required for tetracycline efflux and resistance. Loss-of-function models show reduced transport activity and increased tetracycline sensitivity, providing causal evidence for the gene's role in GO:0015904. Knockout strains are also used as clean backgrounds for complementation with wild-type or mutant transporters.
Point Mutation
CRISPR-mediated point mutations allow precise testing of residues implicated in tetracycline transport, such as Asp-84, Ser-65/67/68, Gln-225 and transmembrane glutamic acid residues. These models distinguish residues required for substrate binding from those required for ion coupling, as illustrated by the DeltaTMS VII-VIII Tet(L) variant that retains cation transport but lacks tetracycline efflux.
Knock-in
Knock-in of tagged or variant transporters, such as epitope-tagged TetA(B) or the DeltaTMS VII-VIII Tet(L) construct, enables localization, biochemical purification and transport assays in a native-like context. Tagged knock-in models are particularly useful for Fe(2+)-tetracycline cleavage mapping and for structural studies of the substrate binding site.
Overexpression
Overexpression of tetracycline transport proteins such as TetA(B) or Tet(L) is used to amplify transport activity for biochemical assays and to test whether increased efflux raises resistance levels. Overexpression models also support inhibitor screening, because higher transport activity provides a larger dynamic range for detecting efflux-pump inhibition.
How EDITGENE Supports tetracycline transmembrane transport Research
Researchers studying tetracycline transmembrane transport-related genes often need to determine whether a candidate gene is causally involved in drug efflux, resistance or host responses. EDITGENE provides publication-ready CRISPR cell models and screening services that allow precise manipulation of transport genes and their regulatory networks.
Contact EDITGENE today to design your custom CRISPR model for tetracycline transmembrane transport research.
Frequently Asked Questions About tetracycline transmembrane transport
What is tetracycline transmembrane transport?
Tetracycline transmembrane transport (GO:0015904) is the directed movement of tetracycline from one side of a membrane to the other; tetracycline is a broad-spectrum antibiotic that blocks aminoacyl-tRNA binding to ribosomes [QuickGO definition].
What genes are involved in tetracycline transmembrane transport?
The best-characterized genes are tetA(B) from Tn10 and tet(L), which encode TetA family antiporters that export tetracycline.
How does TetA(B) transport tetracycline?
TetA(B) is a metal-tetracycline/H+ antiporter that binds tetracycline near Gln-225 in transmembrane helix 7 and translocates it through a channel formed by transmembrane segments 4 and 5.
Which residues are essential for tetracycline transport?
Asp-84 and serine residues on transmembrane helix 3, transmembrane glutamic acid residues, and Gln-225 have been shown to be essential for tetracycline transport.
Can cation transport be separated from tetracycline efflux?
Yes; the DeltaTMS VII-VIII version of Tet(L) retains monovalent cation transport but lacks tetracycline efflux capacity.
Why is tetracycline transmembrane transport important for antibiotic resistance?
Efflux of tetracycline lowers the intracellular drug concentration, protecting ribosomes and conferring resistance in Gram-positive and Gram-negative bacteria.
What methods are used to study tetracycline transmembrane transport?
Radiolabeled transport assays, cysteine-scanning mutagenesis, Fe(2+)-tetracycline cleavage mapping, MIC assays and CRISPR screens are commonly used.
Does antibiotic pollution affect tetracycline transport biology?
Antibiotic pollution can elevate microbial methylmercury production, linking tetracycline transport biology to environmental processes.
What experimental models are available for tetracycline transport research?
CRISPR knockout, point-mutation, knock-in and overexpression cell models, as well as CRISPR library screening, are available from EDITGENE.
How is tetracycline transmembrane transport related to human disease?
It is primarily a bacterial resistance mechanism, but antibiotic exposure and transport also intersect with drug-induced fatty liver disease research.
Conclusion
Tetracycline transmembrane transport (GO:0015904) is a well-defined biological process that controls the movement of a clinically important antibiotic across membranes. The TetA family antiporters, including TetA(B) and Tet(L), provide the best-characterized molecular models for this process, with key residues in transmembrane helices 3, 4, 5, 7 and 8 forming the substrate pathway and coupling ion movement to drug efflux. Understanding this process is essential for antibiotic resistance research, efflux-pump inhibitor development and environmental microbiology. EDITGENE offers a full suite of CRISPR cell models and screening services to accelerate mechanistic and translational studies of tetracycline transmembrane transport.
References
- 1. Jin J et al.. 2001. Twelve-transmembrane-segment (TMS) version (DeltaTMS VII-VIII) of the 14-TMS Tet(L) antibiotic resistance protein retains monovalent cation transport modes but lacks tetracycline efflux capacity.. J Bacteriol 183(8):2667-71 PMID: 11274128
- 2. Wright DJ et al.. 2015. Isolation and characterisation of transport-defective substrate-binding mutants of the tetracycline antiporter TetA(B).. Biochim Biophys Acta 1848(10 Pt A):2261-70 PMID: 26143388
- 3. López-Pascual E et al.. 2024. Drug-Induced Fatty Liver Disease (DIFLD): A Comprehensive Analysis of Clinical, Biochemical, and Histopathological Data for Mechanisms Identification and Consistency with Current Adverse Outcome Pathways.. Int J Mol Sci 25(10) PMID: 38791241
- 4. Yamaguchi A et al.. 1992. Serine residues responsible for tetracycline transport are on a vertical stripe including Asp-84 on one side of transmembrane helix 3 in transposon Tn10-encoded tetracycline/H+ antiporter of Escherichia coli.. FEBS Lett 307(2):229-32 PMID: 1322829
- 5. Iwaki S et al.. 2000. Cysteine-scanning mutagenesis of transmembrane segments 4 and 5 of the Tn10-encoded metal-tetracycline/H+ antiporter reveals a permeability barrier in the middle of a transmembrane water-filled channel.. J Biol Chem 275(30):22704-12 PMID: 10930423
- 6. McMurry LM et al.. 2002. Fe(2+)-tetracycline-mediated cleavage of the Tn10 tetracycline efflux protein TetA reveals a substrate binding site near glutamine 225 in transmembrane helix 7.. J Bacteriol 184(18):5113-20 PMID: 12193628
- 7. Fujihira E et al.. 1996. Transmembrane glutamic acid residues play essential roles in the metal-tetracycline/H+ antiporter of Staphylococcus aureus.. FEBS Lett 391(3):243-6 PMID: 8764982
- 8. Zhang Z et al.. 2026. Antibiotic Pollution Elevates Microbial Methylmercury Production.. Environ Sci Technol 60(13):10274-10284 PMID: 41867126
