Biology subjects

Henry, M.

Publications and source records attributed to Henry, M..

At least 19 recordsLinked to original sources

bioRxiv2026

oidyPeaks: R package for automated flow cytometry cell cycle analysis and visualization in fungal microbes

Karyotypic variation in fungal populations from ecological, clinical, and industrial environments and is also a hallmark of many cancers. The evolutionary dynamics of karyotypic vriants (i.e., changes in the number of chromosomes, either as complete sets or single chromosomes) are the same as any de novo mutation. To quantify karyotypic subpopulations within evolving populations, an unbiased computational method is required to identify subpopulations and quantify their abundance. Flow cytometry is the standard method to measure the genome size from large populations of individual cells. Cell populations typically include cells in all stages of the cell cycle (G0/G1 before DNA replication, S phase during replication, and G2/M after DNA replication but before cell division). Existing mathematical models can be fit to genome-size distributions to determine the base ploidy of a population, but existing algorithms assume a single base ploidy. Mixed-karyotype populations therefore require manual gating to subdivide the flow cytometry data before analysis, which introduces bias, as it is not always clear where or when gates should be drawn. To overcome this, we developed a new method that identifies and quantifies karyotypic subpopulations from flow cytometry data. The open-source R package ploidyPeaks builds on existing Bioconductor tools to import and manipulate standard .fcs flow cytometry files. Using reference populations of known ploidy, we established thresholds to distinguish single-genome size populations and identify candidate mixed-karyotype samples. We then developed a peak-detection algorithm to identify G0/G1 and G2/M peaks, resolve karyotypic subpopulations within mixed populations, and apply nonlinear least-squares fitting of the Dean-Jett-Fox cell-cycle model to each subpopulation, providing a confidence measure for model fit. Compared with existing methods, our approach quantifies genome size in mixed-karyotype populations without manual intervention while providing an objective measure of model fit. We demonstrate the utility of this method on 240 replicate populations initiated from 20 Candida albicans genetic backgrounds evolving for 100 generations to the antifungal drug fluconazole.

microbiology↗

bioRxiv2026

Real-Time Assessment of Murine Cardiac Oxygenation Using Photoacoustic Imaging

BackgroundPerioperative incidents such as hypoxic cardiac injury often have subtle or nonspecific clinical manifestations. Reduction in myocardial oxygenation precedes biochemical changes, as well as electrical and functional changes. Photoacoustic imaging (PAI) is a modality that uses laser irradiation of tissue to generate ultrasonic waves, enabling spatially resolved quantitative mapping of oxygenated and deoxygenated haemoglobin. We investigated the utility of PAI for real-time monitoring of myocardial and great vessel oxygenation. MethodsMale CD-1 mice were anaesthetised, and photoacoustic and simultaneous B-mode images were acquired of the myocardium and right ventricular outflow tract (RVOT), the pulmonary artery, and aorta. PAI was performed at fractional inspired oxygen levels (FiO2) of 100%, 21%, and then 10%. Separate cohorts of mice were exposed to increasing intravenous doses of either combined phenylephrine and isoprenaline, or individual administration of vasoactive or adrenergic agents. ResultsPAI reliably distinguished changes in oxygenation in the RVOT cavity, pulmonary artery, aorta, and myocardium. PAI detected hypoxia-induced changes in oxygenation, revealing greater desaturation in the myocardium than in the RVOT (-9.85%, 95% CI -14.94 to -4.77, P<0.0001). Escalating doses of phenylephrine and isoprenaline caused a progressive desaturation of the myocardium and RVOT (mean [95% CI]; myocardium 16 mg/kg: -14.64% [-27.62 to -1.65], P=0.0038 and RVOT 32 mg/kg: -18.71% [-32.15 to -5.27], P=0.0003). Myocardial deoxygenation was detected before changes in systolic function or electrical abnormalities. ConclusionsThis work demonstrates that PAI can reliably monitor cardiac oxygen desaturation, potentially offering an earlier warning of cardiac dysfunction and injury compared to existing monitoring tools.

physiology↗

bioRxiv2026

Pharmacokinetic Acceleration via CYP3A4 Hyperactivation as a Clinically Actionable Mechanism of Targeted Therapy Resistance in NSCLC

Resistance of cancers to targeted therapies is traditionally framed as a tumor-intrinsic phenomenon, mediated by tumor cell-intrinsic or microenvironmental mechanisms. Here, we identify a tumor-extrinsic, systemic resistance mechanism resulting from hyperactivation of the hepatic cytochrome P450 enzyme, CYP3A4. This tumor-extrinsic resistance mechanism can function independently of, or in tandem with, tumor-intrinsic resistance. Focusing on experimental mouse models of targetable lung cancer, we find that xenobiotic-mediated induction of CYP3A4 results in accelerated drug metabolism and a drastic reduction in systemic and tumor-drug exposure in vivo. CYP3A4 activation can be triggered by chemically unrelated xenobiotics, leading to resistance to a wide range of targeted therapies, including ALK, EGFR, and KRASG12C inhibitors. Retrospective analysis of clinical cohorts suggests that variability in CYP3A4 activity might be a major contributor to variability in clinical outcomes. While higher CYP3A4 activity leads to sub-therapeutic tumor drug exposure and shorter progression-free survival, reduced drug metabolism is expected to result in supratherapeutic exposure and increased systemic toxicity. To address the consequences of abnormal CYP3A4 activity, we utilized mathematical modeling to demonstrate that drug concentrations can be restored through the optimization of dosing amounts and intervals. Further, we show that tumor sensitivity to targeted therapies can be rescued through pharmacological inhibition of CYP3A4. Our findings establish systemic metabolic variability as a bona fide resistance and toxicity driver, providing a translational framework for personalized dosing to maximize both safety and efficacy.

cancer biology↗

bioRxiv2026

Decoding concept representations in aphasia after stroke

Many stroke survivors with aphasia struggle to map their thoughts into words or motor plans. Neuroprostheses that decode concept representations could help these individuals communicate by predicting the words, phrases, or sentences that they are struggling to produce. Here we decoded concept representations measured using functional magnetic resonance imaging (fMRI) from participants with different aphasia profiles. The decoders generated continuous word sequences that could describe the concepts that the participants were hearing about, seeing, or imagining. To forecast how this approach would generalize across the heterogeneity of aphasia profiles, we characterized how stroke affects the anatomical organization and information capacity of conceptual processing. Mapping how concepts are organized across the brain, we found that conceptual tuning during non-linguistic processing was largely consistent between the participants with aphasia and neurologically healthy participants. Comparing information processing between the participants with aphasia and neurologically healthy participants, we found that both groups processed similar amounts of non-linguistic information. Our findings indicate that concept representations can be largely spared in individuals with aphasia and demonstrate how these representations can be decoded to support communication.

neuroscience↗

bioRxiv2025

Radiotherapy Enhancement by Gold Nanocluster-functionalized Nanoliposomes Using Polychromatic Orthovoltage X-ray Irradiation

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal cancers, as the most effective chemoradiation therapies achieve unsatisfactory outcomes while associated with high toxicity. Nanoliposomal drug delivery systems are widely used to improve chemotherapy safety, yet passive release of amphiphilic drugs may still associate with adverse toxicity. To address this, we previously developed nanoliposomes functionalized with hydrophobic gold nanoclusters, demonstrating radiocatalytic activity and enhanced chemoradiotherapy effects in 3D PDAC microtumors under synchrotron irradiation. In this study, gold nanocluster-functionalized nanoliposomes (AuLPs) were optimized and evaluated under 220 kVp orthovoltage X-ray irradiation, widely used in preclinical irradiation systems. AuLPs containing 0.2 mol% gold nanoclusters produced 1.5-fold more reactive oxygen species than unloaded liposomes. However, higher molar ratios were necessary to improve radiotherapy outcomes in 3D PDAC microtumor models following 4 and 8 Gy irradiation. Pharmacokinetics and biodistribution evaluations showed a modest increase in tumor gold content 24 hours post-injection in orthotopic PDAC models. Altogether, these results underscore the potential of gold-radiotherapy-responsive liposomes while highlighting critical formulation challenges, which must be resolved for full therapeutic potential.

bioengineering↗

bioRxiv2025

Non-obese genetic type 2 diabetes causes brain and behavioral hallmarks of chronic stress

The comorbidity of obesity, type 2 diabetes (T2D), and psychiatric disorders-- particularly anxiety and depression--is well documented. However, it remains unclear whether T2D, independently of obesity, contributes to the development of emotional dysfunctions. Furthermore, alterations in the hypothalamic-pituitary-adrenal (HPA) stress axis are commonly associated with both T2D and depression, but the role of stress in emotional disorders linked to T2D has been poorly explored. This study aimed to investigate the impact of T2D, independent of obesity, on the neuroendocrine stress axis, as well as molecular, cellular, and behavioral indicators of emotional dysfunction. Using the non-obese Goto-Kakizaki (GK) rat model of T2D, we assessed the effects of diabetes on hormonal and neuronal stress responses, molecular and structural markers of stress in the brain, and anxiety- and depressive-like behaviors. We also evaluated the impact of adrenalectomy in GK rats to determine the contribution of glucocorticoids to their behavioral impairments. Our findings reveal that non-obese diabetes leads to heightened endocrine and brain responses to stress, along with upregulation of stress-related molecular markers and structural features indicative of chronic stress, particularly in the medial prefrontal cortex. Additionally, GK rats exhibited pronounced anxiety- and depressive-like behaviors. Importantly, lowering glucocorticoid levels in GK rats helped alleviate some of the metabolic and emotional disturbances. This study suggests that T2D, independent of obesity, induces stress-related brain and behavioral changes, partly mediated by glucocorticoids. HighlightsO_LIT2D disrupts endocrine and neural responses to stress. C_LIO_LIT2D alters stress-related gene expression in the medial prefrontal cortex. C_LIO_LIT2D induces structural changes in the medial prefrontal cortex. C_LIO_LIT2D contributes to anxiety- and depressive-like behaviors. C_LIO_LIReducing corticosterone levels mitigates anxiety-like behavior in diabetic rats. C_LI

neuroscience↗

bioRxiv2025

Manganese homeostasis modulates glucan and chitin unmasking in the opportunistic yeast Candida albicans

Candida albicans is a commensal fungus and also the most prevalent human fungal pathogen. The ability of this opportunistic yeast to acquire and maintain homeostatic levels of manganese (Mn), particularly in the metal-limited host environment, is an important determinant of its fitness. Recent studies have underscored the importance of Mn acquisition through members of Smf transporters, in C. albicans virulence and its ability to withstand various stresses. In the present study, we undertook transcriptional profiling in the mutant of the Mn transporter Smf12 under restricted Mn availability to identify processes that are directly affected in defective Mn uptake. Our analysis revealed that smf12 displayed a transcriptional pattern suggestive of a cell wall defect, with many transcripts associated with cell wall biogenesis being differentially regulated. smf12 together with smf11, a mutant of the closest homolog of Smf12, exhibited hypersensitivity to cell wall stressors and an altered cell wall ultrastructure. The smf mutants also exhibited unmasking of both {beta}-glucan and chitin, which unexpectedly resulted in a decreased rate of phagocytosis by macrophages, suggesting impaired recognition or internalization--an observation that challenges the prevailing paradigm. Furthermore, we showed that Mn-mediated unmasking of {beta}-glucan required modulation of glucanase activity and was not mediated through the calcineurin pathway. This study uncovers a novel role for Mn in maintaining cell wall integrity and modulating the exposure of fungal antigenic determinants, further emphasizing the critical role of this metal in supporting the opportunistic nature of C. albicans.

microbiology↗

bioRxiv2024

Trastuzumab deruxtecan combination strongly enhances responses and overcomes sotorasib resistance in KRASG12C-mutant NSCLC

IntroductionRecent advances in the treatment of KRAS-mutant non-small cell lung cancer (NSCLC) have led to the development of KRASG12C inhibitors, such as sotorasib and adagrasib. However, resistance and disease progression remain significant challenges. In this study, we investigated the therapeutic potential of combining trastuzumab deruxtecan (T-DXd), an anti-HER2 antibody-drug conjugate, with sotorasib in KRASG12C-mutant NSCLC, while also evaluating HER2 expression in NSCLC samples. MethodsThe HER2 expression dependence of xenograft responses to sotorasib, T-DXd, and their combination was evaluated in therapy-naive and sotorasib-treated tumors by immunohistochemistry (IHC). Also, we analyzed 191 clinical (pre- or on-treatment) and rapid autopsy (post-treatment) samples from 31 patients with driver-positive and driver-negative advanced stage NSCLC, assessing HER2 expression using interpretation guidelines developed for breast cancer (BC) and gastroesophageal adenocarcinoma (GEA). ResultsIn the majority of preclinical models, including sotorasib-resistant tumors, the sotorasib-T-DXd combination induced stronger and more durable responses compared to monotherapies. The strong effect of the combination therapy was likely attributable to sotorasib-induced adaptive HER2 upregulation; stronger HER2 expression in sotorasib-treated tumors was linked with stronger responses. Although HER2 expression was higher in samples from patients with KRASG12C-mutant NSCLC compared to NSCLC with other driver mutations or no drivers, the difference was not statistically significant. HER2 IHC score discrepancy was also observed between BC and GEA interpretation guidelines. ConclusionsOur results support the potential clinical utility of the sotorasib-T-DXd combination, including tumors with intrinsic and acquired resistance to sotorasib monotherapy. Since the strengths of the responses depend on HER2 expression levels, successful clinical implementation necessitates optimizing patient selection. Our results highlight the complexities of accurate HER2 interpretation in NSCLC and highlight the need for standardized testing methods.

cancer biology↗

bioRxiv2024

Tumor-associated macrophages confer resistance to chemotherapy (Trifluridine/Tipiracil) in digestive cancers by overexpressing Thymidine Phosphorylase

Pyrimidine analogs are part of the first-line chemotherapy regimen for gastrointestinal cancers. Trifluridine combined with tipiracil, a specific thymidine phosphorylase inhibitor, in TAS-102 has recently emerged as a potential alternative in the face of primary or secondary chemoresistance to 5-fluorouracil. Despite its promise, in the current study, we report that macrophage-specific overexpression of thymidine phosphorylase results in macrophage-induced chemoresistance to TAS-102 that is insensitive to tipiracil inhibition. In addition, we demonstrate the human specificity of this mechanism, as mouse macrophages do not express significant levels of thymidine phosphorylase. To study the importance of macrophages in chemoresistance to trifluridine, we developed a humanized mouse model with tumor-implanted human macrophages and demonstrated their important role in treatment resistance to pyrimidine analogs. We also showed in human colorectal cancer that macrophages represent a major source of thymidine phosphorylase expression leading to chemoresistance. SignificanceThymidine phosphorylase overexpression in TAMs confers chemoresistance to TAS-102 in digestive cancers.

pathology↗

bioRxiv2024

An MITF- and mTOR-dependent FLCN pathway suppresses TFE3-driven metastasis in melanoma

Melanoma cells have the ability to switch from a melanocytic and proliferative state to a mesenchymal and invasive state and back again. This plasticity drives intra-tumoral heterogeneity, progression, and therapeutic resistance. Microphthalmia-associated Transcription Factor (MITF) promotes the melanocytic/proliferative phenotype, but factors that drive the mesenchymal/invasive phenotype and the mechanisms that effect the switch between cell states are unclear. Here, we identify the MITF paralog TFE3 and the non-canonical mTORC1 pathway as regulators of the mesenchymal state. We show that TFE3 expression drives the metastatic phenotype in melanoma cell lines and tumors. Deletion of TFE3 in MITF-low melanoma cell lines suppresses their ability to migrate and metastasize. Further, MITF suppresses the mesenchymal phenotype by directly or indirectly activating expression of FNIP1, FNIP2, and FLCN, which encode components of the non-canonical mTORC1 pathway, thereby promoting cytoplasmic retention and lysosome-mediated degradation of TFE3. These findings highlight a molecular pathway controlling melanoma plasticity and invasiveness.

cancer biology↗

bioRxiv2024

Peristromal niches protect lung cancers from targeted therapies through a combined effect of multiple molecular mediators

Targeted therapies directed against oncogenic signaling addictions, such as inhibitors of ALK in ALK+ NSCLC often induce strong and durable clinical responses. However, they are not curative in metastatic cancers, as some tumor cells persist through therapy, eventually developing resistance. Therapy sensitivity can reflect not only cell-intrinsic mechanisms but also inputs from stromal microenvironment. Yet, the contribution of tumor stroma to therapeutic responses in vivo remains poorly defined. To address this gap of knowledge, we assessed the contribution of stroma-mediated resistance to therapeutic responses to the frontline ALK inhibitor alectinib in xenograft models of ALK+ NSCLC. We found that stroma-proximal tumor cells are partially protected against cytostatic effects of alectinib. This effect is observed not only in remission, but also during relapse, indicating the strong contribution of stroma-mediated resistance to both persistence and resistance. This therapy-protective effect of the stromal niche reflects a combined action of multiple mechanisms, including growth factors and extracellular matrix components. Consequently, despite improving alectinib responses, suppression of any individual resistance mechanism was insufficient to fully overcome the protective effect of stroma. Focusing on shared collateral sensitivity of persisters offered a superior therapeutic benefit, especially when using an antibody-drug conjugate with bystander effect to limit therapeutic escape. These findings indicate that stroma-mediated resistance might be the major contributor to both residual and progressing disease and highlight the limitation of focusing on suppressing a single resistance mechanism at a time.

cancer biology↗

bioRxiv2024

The 4T1 breast carcinoma model possesses hybrid epithelial/mesenchymal traits linked to a highly metastatic phenotype

Epithelial-mesenchymal transitions (EMTs) have emerged as a mechanism for carcinomas to gain metastatic capabilities. As classically defined, EMTs entail downregulation of E-cadherin, viewed as a master enforcer of an epithelial phenotype, and upregulation of mesenchymal markers such as N-cadherin and vimentin. Contrary to this, E-cadherin appears to be retained in many invasive carcinomas and promote collective cell invasion. Therefore, major questions remain concerning the role of E-cadherin in metastasis. To investigate how E-cadherin regulates metastasis, we selected murine 4T1 breast carcinoma cells, a widely utilized model of stage IV metastatic breast cancer that retains E-cadherin expression. Using RNA interference and constitutive expression, we demonstrate that the expression level of E-cadherin does not determine 4T1 metastatic capacity in mice. Despite high levels of expression, E-cadherin is unable to confer an epithelial phenotype with stable organized cell-cell junctions. Moreover, orthotopic 4T1 tumors in mice display co-expression of E-cadherin and vimentin and contain subregions of EMT-like loss of E-cadherin. In addition, we find that 4T1 cells co-express epithelial and mesenchymal isoforms of p120-catenin. These findings support 4T1 cells as a model for carcinomas that possess hybrid traits of epithelial and mesenchymal states that promote invasion and metastasis. As such, the 4T1 model provides a platform for investigating strategies to reinstate E-cadherins ability to promote stable cell-cell junctions in E-cadherin-positive cancers, and for identifying which aspects of an epithelial phenotype may serve to facilitate the macroscopic growth of metastatic colonies.

cancer biology↗

bioRxiv2023

Sperm motility restoration in mice suffering from oligo-astheno-teratozoospermia by in vivo injection and electroporation of naked mRNA

Oligo-astheno-teratozoospermia (OAT), a recurent cause of male infertility, is the most frequent disorder of spermatogenesis with a probable genetic cause. Patients and mice bearing mutations in the ARMC2 gene have a decreased sperm concentration, and individual sperm show multiple morphological defects and a lack of motility - a canonical OAT phenotype. Intracytoplasmic sperm injection (ICSI) is required to treat such a condition but it is associated with a small increase in birth defects in comparison to pregnancies not involving assisted conception. Consequently, new targeted treatments are needed to restore fertility. Here, a combination of in vivo injection and electroporation of capped and poly-A-tailed naked mRNA is tested as a strategy to treat ARMC2-related infertility in mouse. mRNAs coding for several reporter genes are tested and the efficiency and the kinetic of expression are assessed using in vivo and in vitro 2D and 3D imaging experiments. We show that mRNA-coded reporter proteins are detected for up to 3 weeks in germ cells, making the use of mRNA possible to treat infertility. We compare these results with those obtained with a non-integrative plasmid Enhanced Episomal Vector (EEV), which induces low and transient expression in spermatogenic cells. Consequently, injection and electroporation of naked mRNA-Armc2 into the testes of Armc2-deficient males were performed and we show the presence of normal and motile sperm in the epididymis. These motile sperm were able to produce embryos by IVF and ICSI. This study demonstrates, for the first time, that mRNA electroporation can restore sperm motility and partially fertilizing ability, providing a proof-of-concept for mRNA-based strategies to correct monogenic causes of male infertility and opening new avenues for male infertility treatment.

molecular biology↗

bioRxiv2023

Ecological specialization and local adaptation in sympatric sexual and asexual grass thrips species

The maintenance of sex is difficult to explain in the face of the demographic advantages of asexuality, especially when sexual and asexual lineages co-occur and compete. Here, we test if niche divergence and specialization can contribute to the maintenance of sympatric populations of two closely related, sexual and asexual Aptinothrips grass thrips species. In mesocosm experiments, ecological niches and ecological specialization were inferred from thrips performances on different grass species used as hosts in natural populations. Sexual and asexual thrips performed best on different grass hosts, indicating niche differentiation. The asexual species was also characterized by a broader fundamental ecological niche than the sexual one. However, niche differentiation is unlikely to explain the maintenance of the two species in sympatry because the reproductive rate of asexual females generally exceeded that of sexual ones. Surprisingly, the asexual but not sexual species showed geographic variation in the fundamental niche. This geographic variation likely stems from different clonal assemblages at different locations because different asexual genotypes have different ecological niches. Across natural populations, the performance of asexual females on a specific grass species was further positively correlated with the frequency of that grass species, consistent with adaptation to locally abundant grasses. Altogether, our results suggest that niche differentiation contributes little to the maintenance of grass thrips species with different reproductive modes and that asexuality facilitates adaptation to a diversity of co-occurring host plants.

evolutionary biology↗

bioRxiv2023

Manganese homeostasis modulates fungal virulence and stress tolerance in Candida albicans

Due to the scarcity of transition metals within the human host, fungal pathogens have evolved sophisticated mechanisms to uptake and utilize these micronutrients at the infection interface. While considerable attention was turned to iron and copper acquisition mechanisms and their importance in fungal fitness, less was done regarding either the role of manganese (Mn) in infectious processes or the cellular mechanism by which fungal cells achieve their Mn- homeostasis. Here, we undertook transcriptional profiling in the pathogenic fungus Candida albicans experiencing both Mn starvation and excess to capture biological processes that are modulated by this metal. We uncovered that Mn scarcity influences diverse processes associated with fungal fitness including invasion of host cells and antifungal sensitivity. We show that Mn levels influence the abundance of iron and zinc emphasizing the complex crosstalk between metals. Deletion of SMF12, a member of Mn Nramp transporters confirmed its contribution to Mn uptake. smf12 was unable to form hyphae and damage host cells and exhibited sensitivity to azoles. We found that the unfolded protein response (UPR), likely activated by decreased glycosylation under Mn limitation, was required to restore growth when cells were shifted from a Mn-starved to a Mn-repleted medium. RNA-seq profiling of cells exposed to Mn excess revealed that UPR was also activated. Furthermore, the UPR signaling axis Ire1-Hac1 was required to bypass Mn toxicity. Collectively, this study underscores the importance of Mn homeostasis in fungal virulence, and comprehensively provides a portrait of biological functions that are modulated by Mn in a fungal pathogen.

microbiology↗

bioRxiv2023

Strain-specific changes in nucleus accumbens transcriptome and motivation for food reward in mice exposed to maternal separation

Adversity in childhood exerts enduring effects on brain and increases the vulnerability to psychiatric diseases. It also leads to a higher risk for eating disorders and obesity. We hypothesised that neonatal stress in mice affects motivation to obtain palatable food in adulthood and changes gene expression in reward system. Male and female pups from C57Bl/6J and C3H/HeN mice strains were subjected to a daily maternal separation (MS) protocol from PND2 to PND14. In adulthood, their motivation for palatable food reward was assessed in operant cages. Compared to control mice, male and female C3H/Hen mice exposed to MS significantly did more lever presses to obtain palatable food especially when the effort required to obtain the reward is high. Transcriptional analysis reveals 375 genes differentially expressed in the nucleus accumbens of male MS C3H/HeN mice compared to the control group, some of these being associated with the regulation of the reward system (e.g. Gnas, Pnoc). Interestingly, C57Bl/6J mice exposed to MS did not show any alteration in their motivation to obtain a palatable reward nor significant changes in gene expression in the nucleus accumbens. In conclusion, neonatal stress produces lasting changes in motivation for palatable food in C3H/HeN offspring but has no impact in C57Bl/6J offspring. These behavioural alterations are accompanied by drastic changes in gene expression specifically within the nucleus accumbens, a key structure in the regulation of motivational processes.

neuroscience↗

bioRxiv2023

The Adr1 transcription factor directs regulation of the ergosterol pathway and azole resistance in C. albicans

Transcription factors play key roles in cellular regulation and are critical in the control of drug resistance in the fungal pathogen Candida albicans. We found that activation of the transcription factor C4_02500C_A (Adr1) conferred significant resistance against fluconazole. In Saccharomyces cerevisiae, Adr1 is a carbon-source-responsive zinc-finger transcription factor required for transcription of the glucose-repressed gene ADH1 and of genes required for ethanol, glycerol, and fatty acid utilization. Motif scanning of promoter elements suggests that Adr1 may be rewired in fungi and governs the ergosterol synthesis pathway in C. albicans. Because previous studies have identified the zinc-cluster transcription factor Upc2 as a regulator of the ergosterol pathway in both fungi, we examined the relationship of Adr1 and Upc2 in sterol biosynthesis in C. albicans. Phenotypic profiles of either ADR1 and UPC2 modulation in C. albicans showed differential growth in the presence of fluconazole; either adr1 or upc2 homozygous deletion results in sensitivity to the drug while their activation generates a fluconazole resistant strain. The rewiring from ergosterol synthesis to fatty acid metabolism involved all members of the Adr1 regulon except the alcohol dehydrogenase Adh1, which remains under Adr1 control in both circuits and may have been driven by the lifestyle of S. cerevisiae, which requires the ability to both tolerate and process high concentrations of ethanol.

genetics↗

bioRxiv2022

Reducing High Pressure Processing Costs: Efficacious Alternatives to Current Standard Procedures in the Food Manufacturing Industry

As a result of recent advancements in design and optimization of high-pressure processing units, the technology is gaining rapid adoption across various sectors of food manufacturing, thus requiring extensive microbiological hurdle validation studies for efficacious and feasible utilization of the technology. Commercial adoption of high-pressure processing is gaining momentum of industrial importance because of recent advances in the engineering of pressure-based pasteurization units. With tremendous ability of plethora of microorganisms to move towards fitness through vertical and horizontal gene transfer mechanisms, prevention of natural and anthropogenic pathogens of public health concern is a daunting task and a moving target. Current study discusses, Reducing the Cost Associated with High Pressure Processing: Efficacious Alternatives to the Current Standard Procedure in the Food Manufacturing Industry, with microbiological challenge studies for inactivation of the pathogen exposed to various times and intensity levels of elevated hydrostatic pressure (Pressure BioScience Inc.). Elevated hydrostatic pressure is a non-thermal procedure that exposes pathogens to pressures of up to 80,000 PSI (>550 MPa). Various times (3, 4, and 5 minutes) at pressure intensity levels of 600 MPa, (87K PSI), 550 MPa (79K PSI), 480 MPa (70K PSI), 415 MPa (60K PSI), and 345 MPa (50K PSI) of elevated hydrostatic pressure (Hub880 Explorer, Pressure BioScience Inc), were investigated at 4{degrees}C and for 45{degrees}C for inactivation of Shiga toxin-producing Escherichia coli O157:H7 (STEC) (ATCC numbers BAA 460, 43888, 43894, 35150, 43889, and 43890) respectively, Big Six non-O157 Shiga toxin-producing E. coli (nSTEC) (ATCC numbers BAA 2196, 2193, 2215, 2440, 2219, and 2192) respectively, Salmonella serovars (ATCC numbers 13076, 8387, 6962, 9270, and 14028) respectively, and Listeria monocytogenes (ATCC numbers 51772, 51779, BAA 2657, and BAA 13932). Studies were conducted in two biologically independent repetitions as a blocking factors of a randomized complete block design containing three repetitions per time/treatment within each block, analyzed statistically using GLM procedures of SAS 9.4 software at type one error level at 5% using Tukey- and Dunnett-adjusted ANOVA. A Barocycler Hub840 unit (Pressure BioScience Inc., Southeastern, MA), equipped with a water jacket and circulating water bath for precise application of hydrostatic pressure and controlled temperature was utilized. Up to 0.95 and 2.60 log reductions (P<0.05) of non-habituated Shiga toxin-producing Escherichia coli Non-O157 at planktonic stages were achieved using application of pressure at 345 MPa and 550 MPa for 5 minutes and 4 minutes, respectively at 4{degrees}C. Up to 4.42 and 5.10 log reductions (P<0.05) of non-habituated Shiga toxin-producing Escherichia coli Non-O157 at planktonic stages were achieved using application of pressure at 345 MPa and 480 MPa for 5 minutes and 4 minutes, respectively at 45{degrees}C. Up to 1.63 and 3.14 log reductions (P < 0.05) of non-habituated Listeria monocytogenes at planktonic stages were achieved using application of pressure at 345 MPa and 600 MPa for 5 minutes and 3 minutes, respectively at 4{degrees}C. Up to 4.91 and 6.37 log reductions (P < 0.05) of non-habituated Listeria monocytogenes at planktonic stages were achieved using application of pressure at 550 MPa and 480 MPa for 4 minutes, respectively at 45{degrees}C. Up to 2.87 and 5.82 log reductions (P< 0.05) of non-habituated Salmonella serovars at planktonic stages were achieved using application of pressure at 345 MPa and 550 MPa for 5 minutes and 4 minutes, respectively at 4{degrees}C. Up to 5.17 and 6.79 log reductions (P< 0.05) of non-habituated Salmonella serovars at planktonic stages were achieved using application of pressure at 415 MPa and 600 MPa for 5 minutes and 3 minutes, respectively at 45{degrees}C. Up to 0.86 and 1.35 log reductions (P<0.05) of non-habituated Shiga toxin-producing Escherichia coli O157:H7 at planktonic stages were achieved using application of pressure at 345 MPa and 480 MPa for 5 minutes and 4 minutes, respectively at 4{degrees}C. Up to 2.02 and 6.12 log reductions (P<0.05) of non-habituated Shiga toxin-producing Escherichia coli O157:H7 at planktonic stages were achieved using application of pressure at 345 MPa and 550 MPa for 5 minutes and 4 minutes, respectively at 45{degrees}C. Results of this study could be incorporated as a part of predictive public health microbiology modeling and risk assessment analysis for prevention of pathogen related disease and illness episodes.

microbiology↗