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Perez, C.

Publications and source records attributed to Perez, C..

At least 37 records · Page 2Linked to original sources

The function of CozE proteins is linked to lipoteichoic acid biosynthesis in Staphylococcus aureus

To maintain cell integrity and facilitate cell division in Staphylococcus aureus, a well-coordinated interplay between membrane biogenesis, peptidoglycan formation, and teichoic acid synthesis is crucial. However, the molecular mechanisms and regulatory pathways that underpin their coordination are still poorly understood. CozE constitute a conserved family of membrane proteins implicated in cell division via regulation of penicillin binding proteins. It has been shown that the two staphylococcal cozE genes (cozEa and cozEb) constitute a synthetic lethal gene pair. Depletion of CozEa and CozEb simultaneously in S. aureus resulted in severely defective cell division phenotypes, reminiscent of cell lacking lipoteichoic acid (LTA). Indeed, we demonstrate that there is an intricate interplay between CozE, biosynthesis of LTA, and membrane homeostasis in S. aureus. By screening for potential genetic links, we establish that there is synthetic lethal relationship between CozE and UgtP, the enzyme synthesizing the LTA glycolipid anchor Glc2DAG. On the contrary, in cells lacking LtaA, the flippase of Glc2DAG, the essentiality of CozEa and CozEb was alleviated. Furthermore, by immunoblotting, we found that CozEb plays a unique role in controlling LTA polymer length and stability. Using reconstituted proteoliposomes, we also demonstrated that CozE proteins modulate the glycolipid flipping activity of LtaA in vitro. Together, the results demonstrate a new function of CozE proteins, facilitating proper membrane homeostasis and LTA biosynthesis in S. aureus.

microbiology↗

BioE3 enables the identification of bona fide targets of E3 ligases

The post-translational modification of proteins by ubiquitination is a highly regulated process that involves a dynamic, three-step enzymatic cascade, where more than 600 E3 ligases play a critical role in recognizing specific substrates for modification. Separating bona fide targets of E3s from E3-interacting proteins remains a major challenge in the field. In this study, we present BioE3, a novel approach for identifying substrates of ubiquitin-like (UbL) E3 ligases of interest. Using BirA-E3 ligase fusion proteins and bioUbLs, the method facilitates site-specific biotinylation of UbL-modified substrates of particular E3s for proteomic identification. We demonstrate that the BioE3 system can identify both known and novel targets of two RING-type ubiquitin E3 ligases: RNF4, known to be involved in DNA damage response and the regulation of PML nuclear bodies, and MIB1, implicated in endocytosis, autophagy, and centrosomal protein homeostasis. We further show the versatility of BioE3 by identifying targets of an organelle-specific E3 (MARCH5) and a relatively uncharacterized E3 (RNF214). Furthermore, we show that BioE3 works with HECT-type E3 ligases and identify novel targets of NEDD4 involved in vesicular trafficking. BioE3 is a powerful tool that enables identification of bona fide substrates of UbL E3 ligases and how they change with chemical perturbations. BioE3 may also be applicable for UbLs beyond Ub and SUMO, as well as other E3 ligase classes. The resulting knowledge can shed light on the regulation of cellular processes by the complex UbL network and provide information useful for strategies such as targeted protein degradation (TPD), advancing our understanding of fundamental biological mechanisms and their applications.

cell biology↗

Virtual tissue microstructure reconstruction by deep learning and fluorescence microscopy

Analyzing tissue microstructure is essential for understanding complex biological systems in different species. Tissue functions largely depend on their intrinsic tissue architecture. Therefore, studying the three-dimensional (3D) microstructure of tissues, such as the liver, is particularly fascinating due to its conserved essential roles in metabolic processes and detoxification. Here, we present TiMiGNet, a novel deep learning approach for virtual 3D tissue microstructure reconstruction using Generative Adversarial Networks (GANs) and fluorescence microscopy. TiMiGNet overcomes challenges such as poor antibody penetration and time-intensive procedures by generating accurate, high-resolution predictions of tissue components across large volumes without the need of paired images as input. We applied TiMiGNet to analyze tissue microstructure in mouse and human liver tissue. TiMiGNet shows high performance in predicting structures like bile canaliculi, sinusoids, and Kupffer cell shapes from actin meshwork images. Remarkably, using TiMiGNet we were able to computationally reconstruct tissue structures that cannot be directly imaged due experimental limitations in deep dense tissues, a significant advancement in deep tissue imaging. Our open-source virtual prediction tool facilitates accessible and efficient multi-species tissue microstructure analysis, accommodating researchers with varying expertise levels. TiMiGNets simplicity and independence from paired images make it a versatile asset. Overall, our method represents a powerful and efficient approach for studying tissue microstructure, with far-reaching applications in diverse biological contexts and species.

bioinformatics↗

Hep3D: A 3D single-cell digital atlas of the liver to study spatio-temporal tissue architecture

Three dimensional (3D) geometrical models are not only a powerful tool for quantitatively characterizing complex tissues but also useful for probing structure-function relationships in a tissue. However, these models are generally incomplete due to experimental limitations in acquiring multiple (>4) fluorescent channels simultaneously. Indeed, predictive geometrical and functional models of the liver have been restricted to few tissue and cellular components, excluding important cellular populations such as hepatic stellate cells (HSCs) and Kupffer cells (KCs). Here, we performed deep-tissue immunostaining, multiphoton microscopy, deeplearning techniques, and 3D image processing to computationally expand the number of simultaneously reconstructed tissue structures. We then generated a spatio-temporal singlecell atlas of hepatic architecture (Hep3D), including all main tissue and cellular components at different stages of post-natal development in mice. We used Hep3D to quantitatively study 1) hepatic morphodynamics from early post-natal development to adulthood, and 2) the structural role of KCs in the murine liver homeostasis. In addition to a complete description of bile canaliculi and sinusoidal network remodeling, our analysis uncovered unexpected spatiotemporal patterns of non-parenchymal cells and hepatocytes differing in size, number of nuclei, and DNA content. Surprisingly, we found that the specific depletion of KCs alters the number and morphology of the HSCs. These findings reveal novel characteristics of liver heterogeneity and have important implications for both the structural organization of liver tissue and its function. Our next-gen 3D single-cell atlas is a powerful tool to understand liver tissue architecture, under both physiological and pathological conditions.

cell biology↗

Socially tolerant macaques use more complex facial behavior than intolerant macaques

The social complexity hypothesis for communicative complexity posits that animal societies with more complex social systems require more complex communication systems. We tested the social complexity hypothesis on three macaque species that vary in their degree of social tolerance and complexity. We coded facial behavior in >3000 social interactions across three social contexts (aggressive, submissive, affiliative) in 389 animals, using the Facial Action Coding System for macaques (MaqFACS). We quantified communicative complexity using three measures of uncertainty: entropy, specificity, and prediction error. We found that the relative entropy of facial behavior was higher for the more tolerant crested macaques as compared to the less tolerant Barbary and rhesus macaques across all social contexts, indicating that crested macaques more frequently use a higher diversity of facial behavior. The context specificity of facial behavior was higher in rhesus as compared to Barbary and crested macaques, demonstrating that Barbary and crested macaques used facial behavior more flexibly across different social contexts. Finally, a random forest classifier predicted social context from facial behavior with highest accuracy for rhesus and lowest for crested, indicating there is higher uncertainty and complexity in the facial behavior of crested macaques. Overall, our results support the social complexity hypothesis.

animal behavior and cognition↗

Competence remodels the pneumococcal cell wall providing resistance to fratricide and surface exposing key virulence factors

Competence development in the human pathogen Streptococcus pneumoniae controls several features such as genetic transformation, biofilm formation and virulence. Competent bacteria produce so called fratricins such as CbpD, that kill non-competent siblings by cleaving peptidoglycan (PGN). CbpD is a choline-binding protein (CBP) that binds to phosphorylcholine residues found on wall- and lipoteichoic acids (WTA and LTA) that together with PGN are major constituents of the pneumococcal cell wall. Competent pneumococci are protected against fratricide by producing the immunity protein ComM. How competence and fratricide contribute to virulence is unknown. Here, using a genome-wide CRISPRi-seq screen, we show that genes involved in teichoic acid biosynthesis are essential during competence. We demonstrate that LytR is the major enzyme mediating the final step in WTA formation, and that, together with ComM, is essential for immunity against CbpD. Importantly, we show that key virulence factors PspA and PspC become more surface-exposed at midcell during competence, in a CbpD-dependent manner. Together, our work supports a model in which activation of competence is crucial for host adherence by increased surface exposure of its various CBPs.

microbiology↗

Dynamic regulation of inter-organelle communication by ubiquitylation controls skeletal muscle development and disease onset

Ubiquitin-proteasome system (UPS) dysfunction is associated with the pathology of a wide range of human diseases including myopathies and muscular atrophy. However, the mechanistic understanding of specific components on the regulation of protein turnover during development and disease progression in skeletal muscle is unclear. Mutations in KLHL40, an E3 ubiquitin ligase cullin3 (CUL3) substrate-specific adapter protein result in a severe form of congenital nemaline myopathy, but the events that initiate the pathology and the mechanism through which it becomes pervasive, remains poorly understood. To characterize the KLHL40-regulated ubiquitin modified proteome during skeletal muscle development and disease onset, we used global, quantitative mass spectrometry-based ubiquitylome and global proteome analyses of klhl40 mutant zebrafish during disease progression. Global proteomics during skeletal muscle development revealed extensive remodeling of functional modules linked with sarcomere formation, energy and biosynthetic metabolic processes and vesicle trafficking. Combined analysis of klh40 mutant muscle proteome and ubiquitylome identified thin filament proteins, metabolic enzymes and ER-Golgi vesicle trafficking pathway proteins regulated by ubiquitylation during muscle development. Our studies identified a role for KLHL40 as a negative regulator of ER-Golgi anterograde trafficking through ubiquitin-mediated protein degradation of secretion associated Ras related GTPase1a (Sar1a). In KLHL40 deficient muscle, defects in ER exit site vesicle formation alter Golgi compartment and downstream transport of extracellular cargo proteins, resulting in structural and functional abnormalities. Our work reveals that the muscle proteome is dynamically fine-tuned by ubiquitylation to regulate skeletal muscle development and uncovers new disease mechanisms for therapeutic development in patients. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/501000v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1950696org.highwire.dtl.DTLVardef@e37313org.highwire.dtl.DTLVardef@9804a6org.highwire.dtl.DTLVardef@59527f_HPS_FORMAT_FIGEXP M_FIG C_FIG

genetics↗

The global distribution and environmental drivers of the soil antibiotic resistome

BackgroundLittle is known about the global distribution and environmental drivers of key microbial functional traits such as antibiotic resistance genes (ARGs). Soils are one of Earths largest reservoirs of ARGs, which are integral for soil microbial competition, and have potential implications for plant and human health. Yet, their diversity and global patterns remain poorly described. Here, we analyzed 285 ARGs in soils from 1012 sites across all continents, and created the first global atlas with the distributions of topsoil ARGs. ResultsWe show that ARGs peaked in high latitude cold and boreal forests. Climatic seasonality and mobile genetic elements, associated with the transmission of antibiotic resistance, were also key drivers of their global distribution. Dominant ARGs were mainly related to multidrug resistance genes and efflux pump machineries. We further pinpointed the global hotspots of the diversity and proportions of soil ARGs. ConclusionsTogether, our work provides the foundation for a better understanding of the ecology and global distribution of the environmental soil antibiotic resistome.

ecology↗

Osmotic stress response in BetP: How lipids and K+ team up to overcome downregulation

The trimeric betaine symporter BetP senses an osmotic upshift via its osmosensory C-terminal domain and responds rapidly with a steep increase in transport rate. Full activation requires both an elevated internal K+ concentration and a yet unknown membrane stimulus. Moreover, the molecular mechanisms of stress sensing and upregulation remain unclear. Here, we show that K+ binding to BetP in vivo is highly cooperative. Using X-ray crystallography, we identify four putative K+ interaction sites at the C-terminal domains of BetP. Single particle CryoEM on BetP reconstituted in amphipols (AMP-BetP), in the absence of K+, revealed that the three C-terminal domains are oriented symmetrically near the membrane surface, representing a new downregulated state. The presence of K+ resulted in asymmetric partial unfolding of the C-terminal domains, which was assigned as an intermediate between the downregulated state and the conformation observed in crystal structures. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy in 2D crystals of BetP reveal glutamate/aspartate and tyrosine responses to K+, in agreement with the identified K+ interaction sites, as well as specific unfolding events in the C-terminal domain upon activation. A rearrangement of the relative protomer orientations confers upregulation through key structural elements involved in the alternating access of BetP affecting sodium and betaine binding affinities. Although K+-specific regulation is unique to BetP we discuss unfolding/refolding of sensory domains as a unifying element in hyperosmotic stress response of osmoregulated transporters.

biophysics↗

ARID1A maintains transcriptionally repressive H3.3 associated with CHD4-ZMYND8 chromatin interactions

ARID1A is a signature subunit of the mammalian SWI/SNF (BAF) chromatin remodeling complex and is mutated at a high rate in malignancies and benign diseases originating from the uterine endometrium. Through genome-wide analysis of human endometriotic epithelial cells, we show that more than half of ARID1A binding sites are marked by the variant histone H3.3, including active regulatory elements. ARID1A loss leads to H3.3 depletion at ARID1A bound active regulatory elements and a concomitant redistribution of H3.3 towards genic elements. ARID1A interactions with the repressive chromatin remodeler CHD4 (NuRD) are associated with H3.3-containing chromatin regulation. ZMYND8, the CHD4-interacting acetyl-histone H4 reader, specifies ARID1A-CHD4-H3.3 target regulatory activity towards histone H4 lysine 16 acetylation (H4K16ac) to repress super-enhancers. ARID1A, H3.3, CHD4, and ZMYND8 co-repress the expression of genes governing extracellular matrix, motility, adhesion, and epithelial-to-mesenchymal transition. Moreover, these gene expression alterations are observed in human endometriomas. Altogether, these studies demonstrate that cooperation among a histone reader and different types of chromatin remodelers safeguards the endometrium through transcriptionally repressive H3.3.

genetics↗

Digital control of c-di-GMP in E. coli balances population-wide developmental transitions and phage sensitivity

Nucleotide-based signaling molecules (NSMs) are widespread in bacteria and eukaryotes, where they control important physiological and behavioral processes. In bacteria, NSM-based regulatory networks are highly complex, entailing large numbers of enzymes involved in the synthesis and degradation of active signaling molecules. How the converging input from multiple enzymes is transformed into robust and unambiguous cellular responses has remained unclear. Here we show that Escherichia coli converts dynamic changes of c-di-GMP into discrete binary signaling states, thereby generating heterogeneous populations with either high or low c-di-GMP. This is mediated by an ultrasensitive switch protein, PdeL, which senses the prevailing cellular concentration of the signaling molecule and couples this information to c-di-GMP degradation and transcription feedback boosting its own expression. We demonstrate that PdeL acts as a digital filter that facilitates precise developmental transitions, confers cellular memory, and generates functional heterogeneity in bacterial populations to evade phage predation. Based on our findings, we propose that bacteria apply ultrasensitive regulatory switches to convert dynamic changes of NSMs into binary signaling modes to allow robust decision-making and bet-hedging for improved overall population fitness.

microbiology↗

Mechanistic basis of choline import involved in teichoic acids and lipopolysaccharide modification

Phosphocholine molecules decorating bacterial cell wall teichoic acids and outer-membrane lipopolysaccharide have significant roles in adhesion to host cells, immune evasion, and persistence. Bacteria carrying the operon that performs phosphocholine decoration, synthesize phosphocholine after uptake of the choline precursor by LicB, a conserved transporter among divergent species. Streptococcus pneumoniae is a prominent pathogen where phosphocholine decoration plays a fundamental role in virulence. Here we present cryo-electron microscopy and crystal structures of S. pneumoniae LicB, revealing distinct conformational states and describing architectural and mechanistic elements essential to choline import. Together with in vitro and in vivo functional characterization, we found that LicB displays proton-coupled import activity and promiscuous selectivity involved in adaptation to choline deprivation conditions, and describe LicB inhibition by synthetic nanobodies (sybodies) and hemicholinium-3. Our results provide novel insights into the molecular mechanism of a key transporter involved in bacterial pathogenesis and establish a basis for inhibition of the phosphocholine modification pathway across bacterial phyla.

biochemistry↗

Evidence for a trap-and-flip mechanism in a proton-dependent lipid transporter

Transport of lipids across membranes is fundamental for diverse biological pathways in cells. Multiple ion-coupled transporters participate in lipid translocation, but their mechanisms remain largely unknown. Major facilitator superfamily (MFS) lipid transporters play central roles in cell wall synthesis, brain development and function, lipids recycling, and cell signaling. Recent structures of MFS lipid transporters revealed overlapping architectural features pointing towards a common mechanism. Here we used cysteine disulfide trapping, molecular dynamics simulations, mutagenesis analysis, and transport assays in vitro and in vivo, to investigate the mechanism of LtaA, a proton-dependent MFS lipid transporter essential for lipoteichoic acids synthesis in the pathogen Staphylococcus aureus. We reveal that LtaA displays asymmetric lateral openings with distinct functional relevance and that cycling through outward- and inward-facing conformations is essential for transport activity. We demonstrate that while the entire amphipathic central cavity of LtaA contributes to lipid binding, its hydrophilic pocket dictates substrate specificity. We propose that LtaA catalyzes lipid translocation by a trap-and-flip mechanism that might be shared among MFS lipid transporters.

biochemistry↗

Evolution of the quorum sensing regulon in cooperating populations of Pseudomonas aeruginosa

The bacterium Pseudomonas aeruginosa is an opportunistic pathogen and it thrives in many different saprophytic habitats. In this bacterium acyl-homoserine lactone quorum sensing (QS) can activate expression of over 100 genes, many of which code for extracellular products. P. aeruginosa has become a model for studies of cell-cell communication and coordination of cooperative activities. We hypothesized that long-term growth of bacteria under conditions where only limited QS-controlled functions were required would result in a reduction in the size of the QS-controlled regulon. To test this hypothesis, we grew P. aeruginosa for about 1000 generations in a condition in which expression of QS-activated genes is required for growth. We compared the QS regulons of populations after about 35 generations to those after about 1000 generations in two independent lineages by using quorum quenching and RNA-seq technology. In one evolved lineage the number of QS-activated genes identified was reduced by about 70% and in the other by about 45%. Our results lend important insights about the variations in the number of QS-activated genes reported for different bacterial strains and, more broadly, about the environmental histories of P. aeruginosa.

microbiology↗

Identification of proximal SUMO-dependent interactors using SUMO-ID

The fast dynamics and reversibility of posttranslational modifications by the ubiquitin family pose significant challenges for research. Here we present SUMO-ID, a technology that merges proximity biotinylation by TurboID and protein-fragment complementation to find SUMO-dependent interactors of proteins of interest. We developed an optimized split-TurboID version and show SUMO interaction-dependent labelling of proteins proximal to PML and RANGAP1. SUMO-dependent interactors of PML are involved in transcription, DNA damage, stress response and SUMO modification and are highly enriched in SUMO Interacting Motifs, but may only represent a subset of the total PML proximal proteome. Likewise, SUMO-ID also allowed us to identify novel interactors of SUMOylated SALL1, a less characterized SUMO substrate. Thus, SUMO-ID is a powerful tool that allows to study the consequences of SUMO-dependent interactions, and may further unravel the complexity of the ubiquitin code.

biochemistry↗

Single cell transfection of human induced pluripotent stem cells using a droplet-based microfluidic system.

Microfluidic tools have recently made possible many advances in biological and biomedical research. Research fields such as Physics, Engineering, Chemistry and Biology have combined to produce innovation in Microfluidics which has positively impacted on areas as diverse as nucleotide sequence, functional genomics, single-cell studies, single molecules assays, and biomedical diagnostics. Among these areas regenerative medicine and stem cells have benefited from Microfluidics due to these tools have had a profound impact on their applications. In the study, we present a high-performance droplet-based system for transfecting individual human-induced pluripotent stem cells. We show that this system has great efficiency in single cells and captured droplets, similar to other microfluidic methods and lower cost. We demonstrate that this microfluidic approach can be associated with the PiggyBac transposase-based system to increase its transfection efficiency. Our results provide a starting point for subsequent applications in more complex transfection systems, single-cell differentiation interactions, cell subpopulations, cell therapy, among other potential applications.

bioengineering↗

On the Origin of Ultraslow Spontaneous Na+ Fluctuations in Neurons of the Neonatal Forebrain

Spontaneous neuronal and astrocytic activity in the neonate forebrain is believed to drive the maturation of individual cells and their integration into complex brain-region-specific networks. The previously reported forms include bursts of electrical activity and oscillations in intracellular Ca2+ concentration. Here, we use ratiometric Na+ imaging to demonstrate spontaneous fluctuations in the intracellular Na+ concentration of CA1 pyramidal neurons and astrocytes in tissue slices obtained from the hippocampus of mice at postnatal days 2-4 (P2-4). These occur at very low frequency ([~]2/h), can last minutes with amplitudes up to several mM, and mostly disappear after the first postnatal week. To further study the mechanisms that may generate such spontaneous fluctuations in neurons, we model a network consisting of pyramidal neurons and interneurons. Experimentally observed Na+ fluctuations are mimicked when GABAergic inhibition in the simulated network is inverted. Both our experiments and computational model show that the application of tetrodotoxin to block voltage-gated Na+ channels or of inhibitors targeting GABAergic signaling respectively, significantly diminish the neuronal Na+ fluctuations. On the other hand, blocking a variety of other ion channels, receptors, or transporters including glutamatergic pathways, does not have significant effects. In addition, our model shows that the amplitude and duration of Na+ fluctuations decrease as we increase the strength of glial K+ uptake. Furthermore, neurons with smaller somatic volumes exhibit fluctuations with higher frequency and amplitude. As opposed to this, the larger relative size of the extracellular with respect to intracellular space observed in neonatal brain exerts a dampening effect. Finally, our model also predicts that these periods of spontaneous Na+ influx leave neonatal neuronal networks more vulnerable to hyperactivity when compared to mature brain. Taken together, our model thus confirms the experimental observations, and offers additional insight into how the neonatal environment shapes early signaling in the brain. Author SummarySpontaneous neuronal and astrocytic activity during the early postnatal period is crucial to the development and physiology of the neonate forebrain. Elucidating the origin of this activity is key to our understanding of the cell maturation and formation of brain-region-specific networks. This study reports spontaneous, ultraslow, large-amplitude, long-lasting fluctuations in the intracellular Na+ concentration of neurons and astrocytes in the hippocampus of mice at postnatal days 2-4 that mostly disappear after the first postnatal week. We combine ratiometric Na+ imaging and pharmacological manipulations with a detailed computational model of neuronal networks in the neonatal and adult brain to provide key insights into the origin of these Na+ fluctuations. Furthermore, our model predicts that these periods of spontaneous Na+ influx leave neonatal neuronal networks more vulnerable to hyperactivity when compared to mature brain.

neuroscience↗

Rice bran supplementation modulates growth, microbiome and metabolome in weaning infants: a clinical trial in Nicaragua and Mali

Rice bran supplementation provides nutrients, prebiotics and phytochemicals that enhance gut immunity, reduce enteric pathogens in mice and diarrhea in neonatal pigs, and warranted attention for improvement of environmental enteric dysfunction (EED) in children at risk. EED is a condition that drives childhood stunting via intestinal dysbiosis and impaired nutrient metabolism. This study investigated effects of rice bran supplementation on growth, EED biomarkers, gut microbiome and metabolome in weaning infants from 6 to 12 months old in Nicaragua and Mali. Healthy infants were randomized to a control group or rice bran group that received daily supplementation at increasing doses each month. Stool microbiomes were characterized using 16S rDNA amplicon sequencing. Stool metabolomes were analyzed using ultra-high-performance liquid-chromatography tandem mass-spectrometry. Statistical comparisons were completed at 6, 8, and 12 months of age. Daily consumption of rice bran was safe and feasible for infant growth, decreasing alpha-1 antitrypsin levels, and modulating gut microbiome and metabolome when compared to control. Rice bran merits investigation as a practical intervention strategy that could decrease EED prevalence and risk for children from low- and middle-income countries where rice is grown as a staple food, and bran is used as animal feed or wasted. One Sentence SummaryDietary rice bran supplementation during infant weaning from 6-12 months of age improved growth outcomes, modulated environmental enteric dysfunction biomarkers, and supported metabolism by the gut microbiome. The authors declare no competing financial or non financial interests to disclose as defined by Nature Research. There are also no other interests that might be perceived to influence the results and/or discussion reported in this paper. Correspondence and requests for materials should be addressed to Dr. Elizabeth Ryan (e.p.ryan@colostate.edu).

clinical trials↗