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Thompson, G.

Publications and source records attributed to Thompson, G..

At least 19 recordsLinked to original sources

Expanding Microgel Parameters to Model the Tumor Microenvironment and Examine Temozolomide Resistance in Glioblastoma

Glioblastoma (GBM) is a highly aggressive brain tumor with a five-year survival rate of less than 5%. The current standard of care established 20 years ago includes maximal surgical resection and administration of alkylating agent temozolomide (TMZ). GBM is highly invasive, and GBM cells that evade surgical resection can become resistant to TMZ and develop new aggressive secondary tumors. Post-relapse there are few treatment options available to patients. Tissue engineering approaches suggest the opportunity to develop in vitro models of the GBM tumor microenvironment that may accelerate the discovery of novel therapies for GBM. Here, we report the adaptation of hydrogel microdroplets (microgels) to encapsulate GBM cells in a tailorable 3D matrix to assess patters of growth and to screen TMZ drug response using patient-derived xenograft (PDX) specimens. We exploit a unique aspect of the microgel system to account for the cellular heterogeneity within the tumor microenvironment (TME). We combine cell-laden microgels generated from TMZ-resistant and TMZ responsive variants of the same PDX specimens to create heterogeneous populations with varying levels of drug sensitivity. We demonstrate a range of drug resistance phenotypes as a function of the ratio of TMZ-responsive to resistance cells and identify the population required for TMZ-resistance to overtake take the response. We then investigate the influence of tumor mimetic shifts in hyaluronic acid bioavailability and hypoxia on patterns of TMZ resistance. We show exposure to matrix-bound hyaluronan increases TMZ resistance and the glioma stem cell population in both cell variants. Lastly, we report an increase in TMZ sensitivity but divergent changes in the GSC subfraction for TMZ resistant vs responsive GBM in the presence of hypoxia. Together, we demonstrate the versatility of cell-laden microgel approach to replicate heterogenous tumor populations, model shifts in the tumor microenvironment, and rapidly screen therapeutic response.

bioengineering↗

An innate immune circuit involving the lectin pathway, complement and lung epithelial cells enforce barrier immunity to inhaled fungal disease

The lung mucosal barrier thwarts many inhaled pathogens, including Coccidioides, the causative agent of Valley Fever. Because the earliest stages of pathogen recognition in the lung remain obscure, we investigated the initial events of barrier immunity in a murine model involving inhalation of Coccidioides sp. arthroconidia. Neutrophils accumulated rapidly, within 24 hours, near fungal spores in the bronchiolar airways. This response was driven by pattern recognition via the lectin complement pathway. Bronchiolar club cells propagated C3a signals and amplified the response via convergent C3aR and P2X7 signaling. We identified several MBL2 and P2RX7 polymorphisms that correlated with progressive disease in humans. Our assays revealed that these mutations caused functional impairments in C3a generation and P2X7 responsiveness. Our findings establish how complement signaling and epithelial sensing coordinate early immune responses to fungal infection, offering insights into essential host defense mechanisms and risk factors for disease progression in coccidioidomycosis.

microbiology↗

Internal decay in living trees: a quantitative tomography framework and its application in a temperate forest

Internal decay in living trees is an important component of carbon and nutrient cycling as well as species and structural diversity maintenance in forest ecosystems. We used sonic and electrical resistance tomography to evaluate and compare the prevalence and severity of stem decay in 57 living trees among four common species (Acer rubrum L., Nyssa sylvatica Marsh., Quercus rubra L., and Tsuga canadensis (L.) Carriere)) with overlapping and non-overlapping distributions across wetland and upland habitat types at the Harvard Forest in Petersham, MA, USA. Independent of tree size, site identity best explained variation in the prevalence of decay across trees sampled, whereas species identity best explained the severity of decay. We categorized trees as having no decay, incipient decay, active decay, or cavities based on combined sonic and electrical resistance metrics, the latter generated by a custom image analysis application. About 31% of wetland trees exhibited incipient decay (compared to 11% in the upland), whereas about 32% of upland trees exhibited active decay (compared to 10% in the wetland). Our study highlights a new quantitative framework for decay categorization through normalized principal component analysis (PCA) and decay analysis software that complements dual tomographic methodology for future investigations of ecological drivers of decay presence and susceptibility.

ecology↗

Structural basis of MK-97 positive allosteric modulation at the M4 mAChR

Positive allosteric modulators (PAMs) of the M4 muscarinic acetylcholine receptor (mAChR) represent a promising therapeutic strategy for treating cognitive deficits and neuropsychiatric disorders. While first-generation M4 mAChR PAMs, like LY2033298, demonstrated proof-of-concept, second-generation compounds, such as MK-97, exhibit substantially improved potency and reduced species variability. Here we report the cryo-EM structure of the M4 mAChR bound to the endogenous agonist, acetylcholine, and MK-97 at 2.7 [A] resolution, revealing the molecular basis for improved M4 mAChR PAM activity. MK-97 adopts a distinctive boomerang-shaped conformation within the extracellular-facing allosteric binding site, with a central pyridine vertex, a lower cyclopentylmethylpyrazole arm extending toward the floor of the orthosteric site, and an upper isoindolinone arm projecting toward extracellular loop 2 (ECL2). This extended binding mode establishes a distributed interaction network across transmembrane helices TM2, TM3, TM5, TM6, and TM7, with key contacts including a hydrogen bond with Y922.64 and a {pi}-{pi} stacking interaction with W4357.35. Integration of structural data, molecular dynamics simulations, and mutagenesis validation reveals that the high affinity of MK-97 derives from optimized engagement across all three binding regions rather than dependence on any single critical contact. Insights from comprehensive structure-activity relationship (SAR) studies provide a molecular framework for the rational design of next-generation M4 mAChR PAMs with improved pharmacological properties. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=70 SRC="FIGDIR/small/723386v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@75cb90org.highwire.dtl.DTLVardef@1876c9corg.highwire.dtl.DTLVardef@1eba8d0org.highwire.dtl.DTLVardef@9818ad_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

The NMR Exchange Format (NEF): Specification and Applications

The NMR Exchange Format (NEF) is a community-driven standard for representing NMR experimental data in a consistent, interoperable, and machine-readable form. Built on the STAR syntax, NEF provides a structured framework for storing and exchanging chemical shifts, peak lists, various types of structural restraints, and related metadata, thus allowing for data exchange across software platforms. By enabling direct, lossless transfer of information, NEF simplifies multi-software workflows, improves reproducibility, and supports FAIR (Findable, Accessible, Interoperable, Reusable) data principles. We describe the NEF specification, its current implementation across commonly used NMR software packages, and its application in areas including biomolecular structure determination, metabolomics, and ligand screening. Testing demonstrates that NEF can be used to exchange complete datasets between programs without loss of information or functionality. We also outline recent developments and future directions, such as inclusion of NMR relaxation data and support for non-standard residue topologies. NEFs growing adoption highlights its potential as a unifying standard for NMR data, enabling more efficient, transparent and collaborative research.

biochemistry↗

Contrasting controls on tree methane emissions in upland and wetland forests

Trees can produce, consume, transport, and emit methane (CH), yet the environmental controls and mechanisms underlying these fluxes remain poorly understood. We combined 1,640 stem-chamber observations (2023-2025) with tower-based meteorology, soil moisture and temperature networks, water table monitoring, and non-destructive tomography to test how hydrology, energy balance, species identity, and internal wood condition regulate stem CH flux. Wetland trees emitted approximately 40-fold more CH than upland trees (1.96 vs. 0.05 nmol m-{superscript 2} s-{superscript 1}). At the wetland, a three-way interaction between soil temperature, water table depth, and species explained 65% of flux variance, consistent with soil-derived CH transport through stems. The wetland specialist Nyssa sylvatica emitted an order of magnitude more CH than co-occurring generalists, likely reflecting flood-tolerance adaptations that enhance gas transport. In contrast, upland fluxes showed minimal environmental control (R{superscript 2} < 9%), with most variance occurring as unexplained temporal variation within individual trees--a pattern suggesting competing methanogenic and methanotrophic processes operating near equilibrium. Internal wood condition, assessed via acoustic and electrical resistance tomography, had opposite effects across sites: decay increased emissions in upland trees, likely by creating anaerobic microsites for in situ production, while decay decreased net emissions in wetland trees, likely by impairing transport of soil-derived CH more than it enhanced in situ production. Together, these results indicate that the dominant controls on tree CH flux differ fundamentally between wetland and upland forests, underscoring the need to represent hydrologic setting, species composition, and tree condition when scaling forest CH contributions to regional budgets.

ecology↗

Endoglucanase-2 (Eng2), a conserved immunodominant antigen in dimorphic fungi that elicits immunity and resistance during infection

Herein, we describe a conserved surface and cell wall protein, Endoglucanase 2 (Eng2), expressed on the etiological agents that cause the endemic systemic mycoses of North America - Blastomyces, Coccidioides and Histoplasma. We demonstrate that despite sequence variation of the protein across these related fungi, exposure to Eng2 vaccinates and protects inbred and humanized HLA-DR4 strains of mice against lethal experimental infections with these fungi by eliciting adaptive immunity mediated by CD4 T cells. We also show that CD4 T cell precursors against Eng2 are detectable in naive individuals and that patients who have recovered from these infections evince a memory and recall CD4 T cell response to Eng2 and its immunodominant epitopes that we have mapped. We create and catalogue new tools and information such as immunodominant peptide epitopes of Eng2 from each fungus recognized by inbred mice and human subjects and we engineer novel peptide-MHC II tetramers for tracking T cells in inbred and HLA-DR4 humanized mice that will be useful for those who study these infections in mice and humans. Lastly, because most patients demonstrate memory and recall responses against Eng2, our work oRers new tools for diagnosis of this collection of infectious diseases across North America.

immunology↗

Prominent white matter related abnormalities associated with diverse molecular alterations in a mouse model of Col4a1 cerebral small vessel disease.

White matter abnormalities are a hallmark of cerebral small vessel disease (cSVD) and are closely linked to cognitive decline and dementia. However, despite their clinical importance, underlying mechanisms remain poorly understood. Collagen IV, encoded by genes COL4A1/COL4A2, is a major component of the basement membrane, a specialised extracellular matrix (ECM) structure. Mutations in these genes cause a genetic form of cSVD. We tested the hypothesis that ECM defects caused by a Col4a1 mutation lead to white matter pathology using an established mouse model of cSVD (Col4a1+/Svc). Behavioural testing with magnetic resonance diffusion tensor imaging, pathology and ultrastructural investigations of white matter were studied. The studies revealed that Col4a1+/Svc mice have cognitive impairments, reduced myelinating oligodendrocyte pools, axonal myelination defects, and altered white matter structural integrity. Proteomic analysis, of isolated white matter from Col4a1+/Svcmice, identified extensive changes to ECM composition and endoplasmic reticulum (ER) biology including ER stress induction. We also demonstrated that targeting protein folding to promote collagen secretion and reduce ER stress, increased myelinating oligodendrocytes and axon-glial integrity in Col4a1+/Svc mice. These data provide novel insight into the pathomolecular mechanisms of white matter abnormalities in cSVD and identify a modifiable pathway as a putative therapeutic target for cSVD.

neuroscience↗

A Novel Sarocladium spinificis Strain Suppresses Coccidioides posadasii Growth: Morphological and Genetic Perspectives

Sarocladium is a diverse fungal genus with implications in both plant and human diseases, exhibiting roles in pathogenicity, endophytism, and biocontrol. This study characterizes two Sarocladium spinificis strains, CA16 (CBS 144516) and CA18 (CBS 144517), isolated from patients initially suspected of having coccidioidomycosis. Morphological, phylogenetic, and genomic analyses confirmed their classification within the Sarocladium genus, closely related to S. spinificis. Both strains exhibited growth at 24{degrees}C and 37{degrees}C, with distinct morphological features. Comparative genomic analysis identified unique orthologous clusters and functional gene families associated with adaptability and potential pathogenicity. Notably, these strains demonstrated enhanced production of secreted proteins, CAZymes, and peptidases, highlighting metabolic versatility. Co-cultivation experiments revealed that S. spinificis strains CA16 and CA18 inhibited the growth of Coccidioides posadasii, suggesting competitive interactions and potential antifungal properties. These findings underscore the ecological and clinical significance of S. spinificis and its impact on microbial communities, advancing our understanding of its diversity, pathogenic potential, and antifungal capabilities. ImportanceAccurate identification and characterization of emerging fungal pathogens are essential for improving diagnosis and treatment. Sarocladium spinificis, though not widely recognized as a human pathogen, exhibits traits suggesting a potential role in opportunistic infections. This study provides the first detailed morphological, phylogenetic, and genomic characterization of clinical S. spinificis isolates, highlighting its ability to survive at body temperature and its antifungal resistance. Additionally, we demonstrate that these strains inhibit Coccidioides posadasii, the agent of Valley fever, suggesting ecological competition or antifungal properties. These findings contribute to understanding fungal interactions in clinical and environmental settings, with implications for fungal pathogenesis and antifungal strategies. By uncovering new aspects of S. spinificis biology, this work expands knowledge of Sarocladium species in human health and lays the foundation for future research on its ecological role, pathogenic potential, and therapeutic applications.

microbiology↗

Golgins support extracellular matrix secretion by collectively maintaining the Golgi structure-function relationship

The secretion of extracellular matrix (ECM) proteins is vital to the maintenance of tissue health. One major control point of this process is the Golgi apparatus, whose dysfunction causes numerous connective tissue disorders. Golgi function is tightly linked to its structure, which is maintained by the cytoskeleton and Golgi organising proteins. We sought to investigate the role of two of these organising proteins, the golgins GMAP210 and Golgin-160, in ECM secretion. We found that loss of either protein had distinct impacts on Golgi organisation. GMAP210 loss caused cisternal fragmentation and dilation, alongside the accumulation of tubulovesicular structures. Meanwhile, Golgin-160 knockout lead to Golgi fragmentation and vesicle build-up. Nonetheless, loss of each protein had a similar impact on ECM secretion and glycosaminoglycan synthesis. We therefore propose that golgins are collectively required to create the correct physical-chemical space to support efficient ECM protein secretion and modification. This is the first time that Golgin-160 has been shown to be required for ECM secretion. SummaryIn this study, Thompson et al demonstrate that two cis-Golgi golgins, GMAP210 and Golgin-160, have distinct, non-redundant roles in maintaining Golgi organisation and that both are required to support the efficient secretion, assembly, and modification of extracellular matrix proteins.

cell biology↗

Integrative analysis of single-cell gene expression: A comprehensive database approach

The exponential growth of single-cell datasets provides unprecedented opportunities to advance our understanding of complex biological systems. However, effectively locating and integrating related studies for meaningful insights remains challenging. Traditional databases primarily index basic metadata, which necessitates time-consuming downloading and re-filtering based on gene expression and cell type or tissue composition, followed by computationally intensive aggregation. This process often results in excessively large datasets that are difficult to analyze effectively, further complicated by batch effects. To address these issues, we have developed a computational approach to efficiently extract and index both expression data and annotations. Our comprehensive database incorporates detailed author annotations and gene expression profiles, enabling refined searches and integrated analyses to uncover common biological patterns while accounting for the repeatability of patterns across multiple studies and mitigating batch effects. This approach significantly reduces computational demands and enhances the accessibility and utility of single-cell transcriptomics data for the broader research community. In the first version, we release a human database comprising 244 datasets from 236 cell types, 35 tissues, and 31 conditions.

bioinformatics↗

Binocular processing facilitates escape behavior through multiple pathways to the superior colliculus

The superior colliculus (SC) is the main brain region regulating innate defensive behaviors to visual threat. Yet, how the SC integrates binocular visual information and to what extent binocular vision drives defensive behaviors is unknown. Here, we show that binocular vision facilitates visually-evoked escape behavior. Furthermore, we find that SC neurons respond to binocular visual input with diverse synaptic and spiking responses, and summate visual inputs largely sublinearly. Using pathway-specific optogenetic silencing we find that contralateral and ipsilateral visual information is carried to binocular SC neurons through retinal, interhemispheric and corticotectal pathways. These pathways carry binocular visual input to the SC in a layer-specific manner, with superficial layers receiving visual information through retinal input, whereas intermediate and deep layers rely on interhemispheric and corticotectal pathways. Together, our data shed light on the cellular and circuit mechanisms underlying binocular visual processing in the SC and its role in escape behavior.

neuroscience↗

Automated cell annotation in scRNA-seq data using unique marker gene sets

Single-cell RNA sequencing has revolutionized the study of cellular heterogeneity, yet accurate cell type annotation remains a significant challenge. Inconsistent labels, technological variability, and limitations in transferring annotations from reference datasets hinder precise annotation. This study presents a novel approach for accurate cell type annotation in scRNA-seq data using unique marker gene sets. By manually curating cell type names and markers from 280 publications, we verified marker expression profiles across these datasets and unified the nomenclature to consistently identify 166 cell types and subtypes. Our customized algorithm, which builds on the AUCell method, achieves accurate cell labeling at single-cell resolution and surpasses the performance of reference-based tools like Azimuth, especially in distinguishing closely related subtypes. To enhance accessibility and practical utility for researchers, we have also developed a user-friendly application that automates the cell typing process, enabling efficient verification and supporting comprehensive downstream analyses.

bioinformatics↗

The CcpNmr Analysis Simulated Metabolomics Database (CASMDB): An Open-Source Collection of Metabolite Annotation Data for 1D 1H NMR-Based Metabolomics

Databases are invaluable for the identification of individual metabolites in untargeted metabolomics analyses, providing annotated pure metabolite references that allow for comparisons with experimentally collected mixture samples. Despite the value of an extensive reference database, publicly available databases for NMR-based metabolomics are often incomplete with respect to experimental conditions and derived NMR annotation parameters, such as peak positions. Hence, they are not designed for visualising the reference spectra alongside an experimental sample spectrum of interest, thus limiting the usefulness of the database. As a consequence, researchers have resorted to their own user- or application based database implementations. In this paper we describe the collection, remediation and integration of annotation data from the publicly available HMDB, BRMB and GISMO NMR metabolomics databases to build the CcpNmr Analysis Simulated Metabolomics Database (CASMDB) that contains 1932 unique metabolite entries. This database, in concert with the AnalysisMetabolomics programme, also allows or accurate simulation of spectra at arbitrary field strengths. Together, these tools underpin the visualising of experimental and simulated metabolite references and their usage in 1D 1H NMR-based metabolomics studies.

biochemistry↗

5-ASA can functionally replace Clostridia to prevent a post-antibiotic bloom of Candida albicans by maintaining epithelial hypoxia

Antibiotic prophylaxis sets the stage for an intestinal bloom of Candida albicans, which can progress to invasive candidiasis in patients with hematologic malignancies. Commensal bacteria can reestablish microbiota-mediated colonization resistance after completion of antibiotic therapy, but they cannot engraft during antibiotic prophylaxis. Here we use a mouse model to provide a proof of concept for an alternative approach, which replaces commensal bacteria functionally with drugs to restore colonization resistance against C. albicans. Streptomycin treatment, which depletes Clostridia from the gut microbiota, disrupted colonization resistance against C. albicans and increased epithelial oxygenation in the large intestine. Inoculating mice with a defined community of commensal Clostridia species reestablished colonization resistance and restored epithelial hypoxia. Notably, these functions of commensal Clostridia species could be replaced functionally with the drug 5-aminosalicylic acid (5-ASA), which activates mitochondrial oxygen consumption in the epithelium of the large intestine. When streptomycin-treated mice received 5-ASA, the drug reestablished colonization resistance against C. albicans and restored physiological hypoxia in the epithelium of the large intestine. We conclude that 5-ASA treatment is a non-biotic intervention that restores colonization resistance against C. albicans without requiring the administration of live bacteria.

microbiology↗

Ketamine Effects on Energy Metabolism, Functional Connectivity and Working Memory in Healthy Humans

Working memory (WM) is a crucial resource for temporary memory storage and the guiding of ongoing behavior. N-methyl-D-aspartate glutamate receptors (NMDARs) are thought to support the neural underpinnings of WM. Ketamine is an NMDAR antagonist that has cognitive and behavioral effects at subanesthetic doses. To shed light on subanesthetic ketamine effects on brain function, we employed a multimodal imaging design, combining gas-free calibrated functional magnetic resonance imaging (fMRI) measurement of oxidative metabolism (CMRO2), resting-state cortical functional connectivity assessed with fMRI, and WM-related fMRI. Healthy subjects participated in two scan sessions in a randomized, double-blind, placebo-controlled design. Ketamine increased CMRO2 and cerebral blood flow (CBF) in prefrontal cortex (PFC) and other cortical regions. However, resting-state cortical functional connectivity was not affected. Ketamine did not alter CBF-CMRO2 coupling brain-wide. Higher levels of basal CMRO2 were associated with lower task-related PFC activation and WM accuracy impairment under both saline and ketamine conditions. These observations suggest that CMRO2 and resting-state functional connectivity index distinct dimensions of neural activity. Ketamines impairment of WM-related neural activity and performance appears to be related to its ability to produce cortical metabolic activation. This work illustrates the utility of direct measurement of CMRO2 via calibrated fMRI in studies of drugs that potentially affect neurovascular and neurometabolic coupling.

neuroscience↗

Pharmacological hallmarks of allostery at the M4 muscarinic receptor elucidated through structure and dynamics

Allosteric modulation of G protein-coupled receptors (GPCRs) is a major paradigm in drug discovery. Despite decades of research, a molecular level understanding of the general principals that govern the myriad pharmacological effects exerted by GPCR allosteric modulators remains limited. The M4 muscarinic acetylcholine receptor (M4 mAChR) is a well-validated and clinically relevant allosteric drug target for several major psychiatric and cognitive disorders. Here, we present high-resolution cryo-electron microscopy structures of the M4 mAChR bound to a cognate Gi1 protein and the high affinity agonist, iperoxo, in the absence and presence of two different positive allosteric modulators, LY2033298 or VU0467154. We have also determined the structure of the M4 mAChR-Gi1 complex bound to its endogenous agonist, acetylcholine (ACh). Structural comparisons, together with molecular dynamics, mutagenesis, and pharmacological validations, have provided in-depth insights into the role of structure and dynamics in orthosteric and allosteric ligand binding, global mechanisms of receptor activation, cooperativity, probe-dependence, and species variability; all key hallmarks underpinning contemporary GPCR drug discovery.

pharmacology and toxicology↗

Enhanced flavour profiles through radicicol induced genomic variation in S. pastorianus lager yeast

The yeasts, Saccharomyces pastorianus, are hybrids of Saccharomyces cerevisiae and Saccharomyces eubayanus and have acquired traits from the combined parental genomes such as ability to ferment a range of sugars at low temperatures and to produce aromatic flavour compounds, allowing for the production of lager beers with crisp, clean flavours. The polyploid strains are sterile and have reached an evolutionary bottleneck for genetic variation. Here we describe an accelerated evolution approach to obtain lager yeasts with enhanced flavour profiles. As the relative expression of orthologous alleles is a significant contributor to the transcriptome during fermentation, we aimed to induce genetic variation by altering the S. cerevisiae to S. eubayanus chromosome ratio. Aneuploidy was induced through the temporary inhibition of the cells stress response and strains with increased production of aromatic amino acids via the Shikimate pathway were selected by resistance to amino acid analogues. Genomic changes such as gross chromosomal rearrangements, chromosome loss and chromosome gain were detected in the characterised mutants, as were Single Nucleotide Polymorphisms in ARO4, encoding for DAHP synthase, the catalytic enzyme in the first step of the Shikimate pathway. Transcriptome analysis confirmed the upregulation of genes encoding enzymes in the Ehrlich pathway and the concomitant increase in the production of higher alcohols and esters such as 2-phenylethanol, 2-phenylethyl acetate, tryptophol, and tyrosol. We propose that the plasticity of polyploid S. pastorianus genomes is an advantageous trait supporting opportunities for genetic diversity in otherwise sterile strains. Significance StatementLager beer is the product of fermentations conducted with Saccharomyces pastorianus, which are hybrids of Saccharomyces cerevisiae and Saccharomyces eubayanus. A quintessential property of lager beers is the distinctive flavours produced during fermentation. Hybrids are sterile and have reached an evolutionary bottleneck. Finding ways to introduce genetic variation as a means of enhancing the flavour profiles is a challenge. Here, we describe an approach to introduce genetic variation by inducing aneuploidy through the temporary inhibition of the cells stress response. Strains with an enhanced flavour production were selected by resistance to amino acid analogues. We identified genomic changes and transcriptome analysis confirmed the upregulation of genes in the Ehrlich pathway which is responsible for the production of flavour compounds.

microbiology↗