Biology subjects

Anderson, M.

Publications and source records attributed to Anderson, M..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Noise-induced changes in rat head stability and orientation correlate with dysfunction of otolith irregular afferents

Exposure to intense noise damages both the cochlea and vestibular end organs. Our group previously reported attenuated vestibular short-latency evoked potentials (VsEP) and reduced numbers of calretinin-positive (CR+) calyces in the saccule following noise exposure. Here, we examined rats resting head orientation with respect to gravity as well as head stability following a 4-hour exposure to 120 dB SPL noise. We also assessed how behavioral changes are related to changes in VsEP waveforms and calretinin expression in the utricle and saccule to elucidate potential underlying mechanisms. We found significant reductions in the P2N2 and N2P3 amplitudes following noise exposure. The number of CR+ calyces in both saccule and utricle were also significantly reduced. The size of the reduction in N2P3 amplitude was significantly correlated to the number of CR+ calyces. Animals with a greater loss of CR+ calyces in the utricle following noise showed significant decreases in the average speed of y-axis rotational head motion, while those with a fewer loss of CR+ calyces showed significant increases. In addition, animals with larger noise-induced changes in VsEP and CR+ calyces held their heads motionless longer following noise exposure. We hypothesize that noise exposure is inherently destructive to an animals head stability and thereby manifests as an increase in average head speed in mildly to moderately affected animals. But when the damage was large enough, animals exhibited reduced duration and head motion speed as a behavioral adaptation. The noise exposure also significantly altered the pitch angle of head orientation in animals who had the largest reduction in CR+ calyces in the saccule, suggesting that saccular irregular afferents, including those that are CR+, are critical in control of head and body posture.

neuroscience↗

bioRxiv2023

Shared and Distinct Mechanisms of UBA1 Inactivation Across Different Diseases

Most cellular ubiquitin signaling is initiated by UBA1, which activates and transfers ubiquitin to tens of E2 enzymes. Clonally acquired UBA1 missense mutations cause an inflammatory-hematologic overlap disease called VEXAS (vacuoles, E1, X-linked, autoinflammatory, somatic) syndrome. Despite extensive clinical investigation into this lethal disease, little is known about the underlying molecular mechanisms. Here, by dissecting VEXAS-causing UBA1 mutations, we discovered that p.Met41 mutations alter cytoplasmic isoform expression, whereas other mutations reduce catalytic activity of nuclear and cytoplasmic isoforms by diverse mechanisms, including aberrant oxyester formation. Strikingly, non-p.Met41 mutations most prominently affect transthioesterification, revealing ubiquitin transfer to cytoplasmic E2 enzymes as a shared property of pathogenesis amongst different VEXAS syndrome genotypes. A similar E2 charging bottleneck exists in some lung cancer-associated UBA1 mutations, but not in spinal muscular atrophy-causing UBA1 mutations, which instead, render UBA1 thermolabile. Collectively, our results highlight the precision of conformational changes required for faithful ubiquitin transfer, define distinct and shared mechanisms of UBA1 inactivation in diverse diseases, and suggest that specific E1-E2 modules control different aspects of tissue differentiation and maintenance.

biochemistry↗

bioRxiv2023

PhIP-Seq uncovers novel autoantibodies and unique endotypes in interstitial lung disease

Interstitial lung diseases (ILDs) are a heterogeneous group of disorders that can develop in patients with connective tissue diseases (CTD). Establishing autoimmunity in ILD impacts prognosis and treatment. ILD patients are screened for autoimmunity by assaying for anti-nuclear autoantibodies, rheumatoid factors and other non-specific tests. However, this approach has not been rigorously validated and may miss autoimmunity that manifests as autoantibodies to tissue antigens not previously defined in ILD. Here, we use Phage Immunoprecipitation-Sequencing (PhIP-Seq) to conduct a large, multi-center unbiased autoantibody discovery screen of ILD patients and controls. PhIP-Seq identified 17 novel autoreactive targets, and machine learning classifiers derived from these targets discriminated ILD serum from controls. Among these 17 candidates, we validated Cadherin Related Family Member 5 (CDHR5) as an autoantigen and found CDHR5 autoantibodies in patients with rheumatologic disorders and importantly, subjects not previously diagnosed with autoimmunity. Lung tissue of CDHR5 autoreactive patients showed transcriptional profiles consistent with activation of NF{kappa}B signaling and upregulation of chitotriosidase (CHIT1), a molecular pathway linked to fibrosis. Our study shows PhIP-Seq uncovers novel autoantibodies in ILD patients not revealed by standard clinical tests. Furthermore, CDHR5 autoantibodies may define a novel molecular endotype of ILD characterized by inflammation and fibrosis.

molecular biology↗

bioRxiv2023

UBE3A and transsynaptic complex NRXN1-CBLN1-GluD1 in a hypothalamic VMHvl-arcuate feedback circuit regulates aggression

The circuit origins of aggression in autism spectrum disorder remain undefined. Here we report Tac1-expressing glutamatergic neurons in ventrolateral division of ventromedial hypothalamus (VMHvl) drive intermale aggression. Aggression is increased due to increases of Ube3a gene dosage in the VMHvl neurons when modeling autism due to maternal 15q11-13 triplication. Targeted deletion of increased Ube3a copies in VMHvl reverses the elevated aggression adult mice. VMHvl neurons form excitatory synapses onto hypothalamic arcuate nucleus AgRP/NPY neurons through a NRXN1-CBLN1-GluD1 transsynaptic complex and UBE3A impairs this synapse by decreasing Cbln1 gene expression. Exciting AgRP/NPY arcuate neurons leads to feedback inhibition of VMHvl neurons and inhibits aggression. Asymptomatic increases of UBE3A synergize with a heterozygous deficiency of presynaptic Nrxn1 or postsynaptic Grid1 (both ASD genes) to increase aggression. Targeted deletions of Grid1 in arcuate AgRP neurons impairs the VMHvl to AgRP/NPY neuron excitatory synapses while increasing aggression. Chemogenetic/optogenetic activation of arcuate AgRP/NPY neurons inhibits VMHvl neurons and represses aggression. These data reveal that multiple autism genes converge to regulate the VMHvl-arcuate AgRP/NPY glutamatergic synapse. The hypothalamic circuitry implicated by these data suggest impaired excitation of AgRP/NPY feedback inhibitory neurons may explain the increased aggression behavior found in genetic forms of autism. One Sentence SummaryA feedback circuit in the hypothalamus that inhibits aggression is impaired by converging autism genetic defects.

neuroscience↗

bioRxiv2023

Gardnerella Diversity and Ecology in Pregnancy and Preterm Birth

The vaginal microbiome has been linked to numerous negative health outcomes including preterm birth. Specific taxa, including Gardnerella spp., have been identified as risk factors for these conditions. Historically, microbiome analysis methods have treated all Gardnerella spp. as one species, but the broad diversity of Gardnerella has recently become more apparent. In the present study, we explore the diversity of Gardnerella clades and genomic species in the vaginal microbiome of pregnant women and their impacts on microbiome composition and associations with preterm birth. Shotgun metagenomic sequencing data collected longitudinally from three distinct cohorts of pregnant women were assessed. Relative abundance of Gardnerella clades and genomic species and other taxa was quantified, and associations between Gardnerella clades and signatures of the vaginal microbiome were measured. We also assessed the diversity and abundance of Gardnerella variants in 16S rRNA gene amplicon sequencing data from seven previously conducted studies in differing populations on the vaginal microbiome and preterm birth. Individual microbiomes often contained multiple Gardnerella variants, and the number of clades was associated with increased microbial load. The genus Gardnerella was also associated with increased microbial load, or the ratio of non-human reads to human reads. Taxon co-occurrence patterns matched previously described community structures, and were largely consistent across Gardnerella clades and among cohorts. Some variants previously described as rare were prevalent in other cohorts, highlighting the importance of surveying a diverse set of populations to fully capture the diversity of Gardnerella. The diversity of Gardnerella both across populations and within individual vaginal microbiomes has long been unappreciated, as has been the intra-species diversity of many other members of the vaginal microbiome.1 The broad genomic diversity of Gardnerella has led to its reclassification as multiple species; here we demonstrate the diversity of Gardnerella found within and between vaginal microbiomes. Further studies should investigate the phenotypes of Gardnerella variants that may underlie the mechanisms by which Gardnerella species may differentially shape the vaginal microbiome.

microbiology↗

bioRxiv2022

De novo identification of CD4+ T cell epitopes

CD4+ T cells recognize peptide antigens presented on class II Major Histocompatibility Complex (MHC-II) molecules to carry out their function. The remarkable diversity of T cell receptor (TCR) sequences and lack of antigen discovery approaches for MHC-II make profiling the specificities of CD4+ T cells challenging. We have expanded our platform of Signaling and Antigen-presenting Bifunctional Receptors to encode MHC-II molecules presenting covalently linked peptides (SABR-IIs) for CD4+ cell antigen discovery. SABR-IIs can present epitopes to CD4+ T cells and induce signaling upon their recognition, allowing a readable output. Here, we demonstrate that SABR-IIs libraries presenting endogenous and post-translationally modified epitopes can be used for antigen discovery. Using SABR-II libraries in conjunction with single cell RNA sequencing, we de-convoluted multiple highly expanded TCRs from pancreatic islets of Non-Obese Diabetic (NOD) mice. We compounded antigen discovery by incorporating computational TCR similarity prediction metrics followed by experimental validation. Finally, we showed SABR-IIs presenting epitopes in class II HLA alleles can be used for antigen discovery for human CD4+ T cells. Taken together, we have developed a rapid, flexible, scalable, and versatile approach for the de novo identification of CD4+ T cell ligands from single cell RNA sequencing data using experimental and computational approaches.

immunology↗

bioRxiv2022

Structural Premise of Selective Deubiquitinase USP30 Inhibition by Small-Molecule Benzosulfonamides

Dampening functional levels of the mitochondrial deubiquitylating enzyme USP30 has been suggested as an effective therapeutic strategy against neurodegenerative disorders such as Parkinsons Disease. USP30 inhibition may counteract the deleterious effects of impaired turnover of damaged mitochondria which is inherent to both familial and sporadic forms of the disease. Small-molecule inhibitors targeting USP30 are currently in development, but little is known about their precise nature of binding to the protein. We have integrated biochemical and structural approaches to gain novel mechanistic insights into USP30 inhibition by a small-molecule benzosulfonamide containing compound, 39. Activity-based protein profiling (ABPP) mass spectrometry confirmed target engagement, the high selectivity, and potency of 39 for USP30 against 49 other deubiquitylating enzymes in a neuroblastoma cell line. In vitro characterization of 39 enzyme kinetics infers slow and tight binding behavior, which is comparable with features of covalent modification of USP30. Finally, we blended hydrogen-deuterium exchange mass spectrometry and computational docking to elucidate the molecular architecture and geometry of USP30 complex formation with 39, identifying structural rearrangements at the cleft of the USP30 thumb and palm subdomains. These studies suggest that 39 binds to the thumb-palm cleft that guides the ubiquitin C-terminus into the active site, thereby preventing ubiquitin binding and isopeptide bond cleavage, and confirming its importance in the inhibitory process. Our data will pave the way for the design and development of next-generation inhibitors targeting USP30 and associated deubiquitinylases.

biochemistry↗

bioRxiv2022

EEG evidence that morally relevant autobiographical memories can be suppressed

Remembering unpleasant events can trigger negative feelings. Fortunately, research indicates that unwanted memories can be suppressed to prevent them from intruding into awareness, improving our mental state. The current scientific understanding of memory suppression is, however, based mostly on simpler memories such as associations between words or pictures, which may not reflect how people control unpleasant memory intrusions in everyday life. Here, we investigated the neural and behavioural dynamics of suppressing personal and emotional autobiographical memories using a modified version of the Think/No-Think task. We asked participants to suppress memories of their own past immoral actions, which were hypothesised to be both highly intrusive and motivating to suppress. We report novel evidence from behavioural, ERP and EEG oscillation measures that autobiographical memory retrieval can be suppressed and suggest that autobiographical suppression recruits similar neurocognitive mechanisms as suppression of simple laboratory associations. Suppression did fail sometimes, and EEG oscillations indicated that such memory intrusions occurred from lapses in sustained control. Importantly however, participants improved at limiting intrusions with repeated practice. Furthermore, both behavioural and EEG evidence indicated that intentional suppression may be more difficult for memories of our morally wrong actions than memories of our morally right actions. The findings elucidate the neurocognitive correlates of autobiographical retrieval suppression and have implications for theories of morally motivated memory control.

neuroscience↗

bioRxiv2021

Altered circadian rhythms and sleep in a new Angelman Syndrome mouse model

Normal neurodevelopment requires precise expression of the key ubiquitin ligase gene Ube3a. Comparing newly generated mouse models for Ube3a down-regulation (models of Angelman syndrome) vs. Ube3a up-regulation (models for autism), we find reciprocal effects of Ube3a gene dosage on phenotypes associated with circadian rhythmicity, including the amount of locomotor activity. In contrast to previous reports, we find that Ube3a is imprinted in neurons of the suprachiasmatic nuclei, the pacemaking circadian brain locus. In addition, Ube3a-deficient mice lack the typical drop in wake late in the dark period and have blunted responses to sleep deprivation. Suppression of physical activity by light in Ube3a-deficient mice is not due to anxiety as measured by behavioral tests and stress hormones; quantification of stress hormones may serve as an easily measurable biomarker for evaluating potential therapeutic treatments for Angelman syndrome. We conclude that reduced Ube3a gene dosage affects not only neurodevelopment but also sleep patterns and circadian rhythms.

neuroscience↗

bioRxiv2021

Neural dynamics of retrieval suppression in abolishing item-specific cortical pattern of unwanted emotional memories

When reminded of an unpleasant experience, people often try to exclude the unwanted memory from awareness, a process known as retrieval suppression. Despite the importance of this form of mental control to mental health, the ability to track, in real time, individual memories as they are suppressed remains elusive. Here we used multivariate decoding on EEG data to track how suppression unfolds in time and to reveal its impact on cortical patterns related to individual memories. We presented reminders to aversive scenes and asked people to either suppress or to retrieve the scene. During suppression, mid-frontal theta power within the first 500 ms distinguished suppression from passive viewing of the reminder, indicating that suppression rapidly recruited control. During retrieval, we could discern EEG cortical patterns relating to individual memories-initially, based on theta-driven, visual perception of the reminders (0-500 ms) and later, based on alpha-driven, reinstatement of the aversive scene (500-3000 ms). Critically, suppressing retrieval weakened (during 420-600 ms) and eventually abolished item-specific cortical patterns, a robust effect that persisted until the reminder disappeared (1200-3000 ms). Actively suppressing item-specific cortical patterns, both during an early (300-680 ms) window and during sustained control, predicted later episodic forgetting. Thus, both rapid and sustained control contribute to abolishing cortical patterns of individual memories, limiting awareness, and precipitating later forgetting. These findings reveal how suppression of individual memories from awareness unfolds in time, presenting a precise chronometry of this process.

neuroscience↗

bioRxiv2021

Anterior Cingulate Cortex Signals the Need to Control Intrusive Thoughts During Motivated Forgetting

How do people limit awareness of unwanted memories? Evidence suggests that when unwelcome memories intrude, a retrieval stopping process engages the right dorsolateral prefrontal cortex (rDLPFC; Anderson et al., 2004) to inhibit hippocampal activity (Benoit and Anderson, 2012; Benoit et al., 2015; Gagnepain et al., 2017) and disrupt retrieval. It remains unknown how and when the need to engage prefrontal control is detected, and whether control operates proactively to prevent an unwelcome memory from being retrieved, or must respond reactively, to counteract its intrusion. We hypothesized that dorsal anterior cingulate cortex (dACC) achieves this function by detecting signals indicating that an unwanted trace is emerging in awareness, and transmitting the need for inhibitory control to right DLPFC (Alexander and Brown, 2011; Botvinick et al., 2001). During a memory suppression task, we measured trial-by-trial variations in dACCs theta power and N2 amplitude, two electroencephalographic (EEG) markers of the need for enhanced control (Cavanagh and Frank, 2014). With simultaneous EEG-fMRI recordings, we tracked dynamic interactions between the dACC, rDLPFC and hippocampus during suppression. EEG analyses revealed a clear role of dACC in detecting the need for memory control, and in upregulating prefrontal inhibition. Importantly, we identified dACC contributions before episodic retrieval could have occurred (500 ms) and afterwards, indicating distinct proactive and reactive control signalling. Stronger proactive control by the dACC led to reduced hippocampal activity and diminished overall blood-oxygen-level-dependent (BOLD) signal in dACC and rDLPFC, suggesting that pre-empting retrieval early reduced overall control demands. However, when dACC activity followed the likely onset of recollection, retrieval was cancelled reactively: effective connectivity analyses revealed robust communication from dACC to rDLPFC and from rDLPFC to hippocampus, tied to successful forgetting. Together, our findings support a model in which dACC detects the emergence of unwanted content, triggering top-down inhibitory control, and in which rDLPFC countermands intruding thoughts that penetrate awareness.

neuroscience↗

bioRxiv2021

Structural basis for acyl chain control over glycosphingolipid sorting and vesicular trafficking

The complex sphingolipids exhibit a diversity of ceramide acyl chain structures that influence their trafficking and intracellular distributions, but how the cell discerns among the different ceramides to affect such sorting remains unknown. To address mechanism, we synthesized a library of GM1 glycosphingolipids with naturally varied acyl chains and quantitatively assessed their sorting among different endocytic pathways. We found that a stretch of at least 14 saturated carbons extending from C1 at the water-bilayer interface dictated lysosomal sorting by exclusion from endosome sorting tubules. Sorting to the lysosome by the C14*-motif was cholesterol dependent. Perturbations of the C14*-motif by unsaturation enabled GM1 entry into endosomal sorting tubules of the recycling and retrograde pathways independently of cholesterol. Unsaturation occurring beyond the C14*-motif in very long acyl chains rescued lysosomal sorting. These results define a structural motif underlying membrane organization of sphingolipids and implicate cholesterol-sphingolipid nanodomain formation in sorting mechanisms.

cell biology↗

bioRxiv2021

CRISPR/Cas-9 mediated knock-in by homology dependent repair in the West Nile Virus vector Culex quinquefasciatus Say

Culex quinquefasciatus Say is a brown, medium sized mosquito distributed widely in both tropical and subtropical regions of the world. It is a night-active, opportunistic blood-feeder and is responsible for vectoring many animal and human diseases, including West Nile Virus and avian malaria. Current vector control methods (e.g. physical / chemical) are increasingly ineffective; use of insecticides also imposes some hazards to both human and ecosystem health. Recent advances in genome editing have allowed the development of genetic methods of insect control, which is species-specific and, theoretically, highly effective. CRISPR/Cas9 is a bacteria-derived programmable gene editing tool that has been shown to be functional in a range of species. We demonstrate here, the first successful germline gene knock-in by homology dependent repair in C. quinquefasciatus. Using CRISPR/Cas9, we integrated exogenous sequence comprising a sgRNA expression cassette and marker gene encoding a fluorescent protein fluorophore (Hr5/IE1-DsRed, Cq7SK-sgRNA) into the kynurenine 3-monooxygenase (kmo) gene. We achieved a minimum transformation rate of 2.8% similar to rates achieved in other mosquito species. Precise knock-in at the intended locus was confirmed by sequencing. Insertion homozygotes displayed a white eye phenotype in early-mid stage larvae and a recessive lethal phenotype by pupation. This work shows an alternative and efficient method for genetic engineering of C. quinquefasciatus, providing a new tool for researchers interested in developing genetic control tools for this vector.

bioengineering↗

bioRxiv2020

A CRISPR endonuclease gene drive reveals two distinct mechanisms of inheritance bias

RNA guided CRISPR gene drives have shown the capability of biasing transgene inheritance in multiple species. Among these, homing endonuclease drives are the most developed. In this study, we report the functioning of sds3, bgcn, and nup50 expressed Cas9 in an Aedes aegypti homing split drive system targeting the white gene. We report their inheritance biasing capability, propensity for maternal deposition, and zygotic/somatic expression. Additionally, by making use of the tight linkage of white to the sex-determining locus, we were able to elucidate mechanisms of inheritance bias. We find inheritance bias through homing in double heterozygous males, but find that a previous report of the same drive occurred through meiotic drive. We propose that other previously reported homing design gene drives may in fact bias their inheritance through other mechanisms with important implications for gene drive design.

genetics↗

bioRxiv2020

Parabrachial complex processes dura inputs through a direct trigeminal ganglion-to-parabrachial connection

Migraines cause significant disability and contribute heavily to healthcare costs. Irritation of the meninges outermost layer (the dura mater), and trigeminal ganglion activation contribute to migraine initiation. Maladaptive changes in central pain-processing regions are also important in maintaining pain. The parabrachial complex (PB) is a central region that mediates chronic pain. PB receives diverse sensory information, including a direct input from the trigeminal ganglion. We hypothesized that PB processes inputs from the dura. Using in vivo electrophysiology recordings from single units in anesthetized rats we identified 58 neurons in lateral PB that respond reliably and with short latency to electrical dura stimulation. After injecting tracer into PB, anatomical examination reveals retrogradely labeled cell bodies in the trigeminal ganglion. Neuroanatomical tract-tracing revealed a population of neurons in the trigeminal ganglion that innervate the dura and project directly to PB. These findings indicate that PB is strategically placed to process dura inputs, and suggest that it is directly involved in the pathogenesis of migraine headaches.

neuroscience↗

bioRxiv2020

Single cell transcriptome analysis defines novel heterogeneity within the pancreatic ductal tree

Lineage tracing using genetically engineered mouse models is an essential tool for investigating cell-fate decisions of progenitor cells and biology of mature cell types, with relevance to physiology and disease progression. To study disease development, an inventory of an organs cell types and understanding of physiologic function is paramount. Here, we performed single-cell RNA sequencing to examine heterogeneity of murine pancreatic duct cells, pancreatobiliary cells, and intrapancreatic bile duct cells. We describe an epithelial-mesenchymal transitory axis in our three pancreatic duct subpopulations and identify SPP1 as a regulator of this fate decision as well as human duct cell de-differentiation. Our results further identify functional heterogeneity within pancreatic duct subpopulations by elucidating a role for Geminin in accumulation of DNA damage in the setting of chronic pancreatitis. Our findings implicate diverse functional roles for subpopulations of pancreatic duct cells in maintenance of duct cell identity and disease progression and establish a comprehensive road map of murine pancreatic duct cell, pancreatobiliary cell, and intrapancreatic bile duct cell homeostasis. SIGNIFICANCEMurine models are extensively used for pancreatic lineage tracing experiments and investigation of pancreatic disease progression. Here, we describe the transcriptome of murine pancreatic duct cells, intrapancreatic bile duct cells, and pancreatobiliary cells at single cell resolution. Our analysis defines novel heterogeneity within the pancreatic ductal tree and supports the paradigm that more than one population of pancreatic duct cells harbors progenitor capacity. We identify and validate unique functional properties of subpopulations of pancreatic duct cells including an epithelial-mesenchymal transcriptomic axis and roles in chronic pancreatic inflammation.

bioinformatics↗

bioRxiv2020

Differences in Chemo-signaling Compound-Evoked Brain Activity in Male and Female Young Adults: A Pilot Study in the Role of Sexual Dimorphism in Olfactory Chemo-Signaling

IntroductionPrevious studies have shown that putative pheromones 4,16-androstadien-3-one (AND) and estra-1,3,5(10),16-tetraen-3-ol (EST) cause activation in the preoptic area/anterior hypothalamus in men and women. Sex differences in neural activation patterns have been demonstrated when participants are subject to pheromone stimulation; however, whether other compounds give rise to similar neural activity has not been completely investigated. MethodsTwenty-nine young adults [16 female (21.3+/-0.54; mean yrs+/-SE), 13 male (22.85+/-0.42)] participated in a 3-block design, where participants were exposed to a scent (lavender), a synthetic male pheromone (4,16-androstadien-3b-ol; ALD), and a synthetic female pheromone (1,3,5(10),16-Estratetraen-3-ol; EST) via an automated olfactometer. Whole-brain, high-resolution (1.8mm3) functional MRI data from a Siemens Trio 3T MRI scanner were collected during all blocks. Five adults were excluded due to excessive movement. MANOVA analysis, a 2 x 3 multivariate model and analysis of 2x2 effects between sex and subsets of stimuli was done for activation over the whole brain and small volumes involved in olfaction. ResultsExploratory analysis of 2x2 effects between sex and subsets of stimuli exhibited significant interactions when assessing activations over the whole brain, and small volumes involved in olfaction. The left and right frontal poles (LFP, RFP) shows significant interaction when assessing sex with lavender and EST for whole brain analysis. For small volume analysis, the right orbitofrontal cortex (ROFC) exhibited a sex with lavender and ALD interaction, and a sex with lavender and EST interaction was observed in the left inferior frontal gyrus (LIFG). Main effects of sex, stimulus, or interaction show no differences analyzed using a 2 x 3 multivariate model. ConclusionThe study shows there is a sexually dimorphic response in the olfactory system to pheromones not previously studied. Scents like lavender do not have this same response. These distinct functional differences in activation patterns may be a result of neural development and maturation differences between sexes. Future studies should expand this pilot study and involve a younger demographic to accurately determine the age at which the olfactory response differentiates between males and females.

neuroscience↗

bioRxiv2020

Resistance to the antifungal activity of Aprotinin occurs through mutations in genes that function in cation homeostasis

An increase in the prevalence of fungal infections is coinciding with an increase of resistance to current clinical antifungals, placing pressure on the discovery of new antifungal candidates. One option is to investigate drugs that have been approved for use for other medical conditions that have secondary antifungal activity. Aprotinin, also known as Bovine Pancreatic Trypsin inhibitor (BPTI), is an antifibrinolytic that has been approved for systemic use in patients in some countries. Bleackley and coworkers (2014) revealed that BPTI also has antifungal activity against S. cerevisiae and C. albicans and does this by targeting the magnesium transporter ALR1. Here we have further investigated the potential for aprotinin to be used as an antifungal by assessing the development of resistance. We used an in vitro model to assess the evolution of BPTI resistance/tolerance whereby BPTI was serial passaged with the model organism S. cerevisiae. Resistance to BPTI developed more quickly than resistance to the plant defensin NaD1 and the clinical antifungal, caspofungin. Full genome sequencing of resistant lines revealed that resistance to BPTI developed as the result of a deleterious mutation in either the ptk2 or sky1 genes. This revealed that cation homeostasis and transport functions were particularly affected in S. cerevisiae after exposure to BPTI. Therefore, the mutations in these genes probably decreases release of magnesium and other cations from the cell, protecting the yeast from the limiting intracellular magnesium levels that arise when BPTI blocks the magnesium transporter Alr1p.

microbiology↗