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INTRODUCTION: Psoriasis is a papulosquamous condition characterized by type 1 (T1) inflammation, while chronic rhinosinusitis (CRS) concurrent with asthma is commonly a type 2 (T2) process. Since psoriasis is predictive for higher rates of CRS, our objective was to determine whether CRS with concurrent psoriasis would share its T1 pathogenic signature. In comparison to T1 CRS, a T2 process can be predicted by presence of more extensive sinus disease via Lund-MacKay score, reduced sense of smell, and greater concurrence of purulent drainage and pain/pressure. METHODS: Subjective measurements of CRS included the Sino-Nasal Outcome Test (SNOT-22) and objective measurements included Lund-MacKay sinus CT score and endoscopic scoring. Outcomes were compared with control subjects with CRS co-presenting with allergies, asthma, or aspirin-exacerbated respiratory disease (AERD). RESULTS: A total of 62 patients (12 CRS alone, 14 CRS/psoriasis, 12 CRS/AERD, 12 CRS/allergic asthmatic, 12 CRS/non-allergic asthmatic) were included. Comparative analysis utilizing χ2 revealed no significant differences in any factor between CRS/psoriatic patients and all other groups associated with T2 presentations. Specifically, psoriatic patients had comparable reductions in smell, similar complaints of pain/pressure, negligible purulent drainage/crusting, and comparable extent of disease on their CT scan, as well as similar blood eosinophilia. The only significant difference was in lack of productivity (p < 0.05) with trends toward reduced concentration, waking up tired, and lack of sleep parameters presumably related to systemic psoriatic manifestations. CONCLUSIONS: Despite the increased prevalence of CRS in psoriasis patients, our data suggest that when present, psoriasis does not predict the presence of a T1 process in the sinuses.
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The spectacular radiation of insects has produced a stunning diversity of phenotypes. During the past 250 years, research on insect systematics has generated hundreds of terms for naming and comparing them. In its current form, this terminological diversity is presented in natural language and lacks formalization, which prohibits computer-assisted comparison using semantic web technologies. Here we propose a Model for Describing Cuticular Anatomical Structures (MoDCAS) which incorporates structural properties and positional relationships for standardized, consistent, and reproducible descriptions of arthropod phenotypes. We applied the MoDCAS framework in creating the ontology for the Anatomy of the Insect Skeleto-Muscular system (AISM). The AISM is the first general insect ontology that aims to cover all taxa by providing generalized, fully logical, and queryable, definitions for each term. It was built using the Ontology Development Kit (ODK), which maximizes interoperability with Uberon (Uberon multispecies anatomy ontology) and other basic ontologies, enhancing the integration of insect anatomy into the broader biological sciences. A template system for adding new terms, extending, and linking the AISM to additional anatomical, phenotypic, genetic, and chemical ontologies is also introduced. The AISM is proposed as the backbone for taxon-specific insect ontologies and has potential applications spanning systematic biology and biodiversity informatics, allowing users to: 1) use controlled vocabularies and create semiautomated computer-parsable insect morphological descriptions; 2) integrate insect morphology into broader fields of research, including ontology-informed phylogenetic methods, logical homology hypothesis testing, evo-devo studies, and genotype to phenotype mapping; and 3) automate the extraction of morphological data from the literature, enabling the generation of large-scale phenomic data, by facilitating the production and testing of informatic tools able to extract, link, annotate, and process morphological data. This descriptive model and its ontological applications will allow for clear and semantically interoperable integration of arthropod phenotypes in biodiversity studies.
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Artrópodes , Animais , Filogenia , Insetos , Informática , BiodiversidadeRESUMO
Cystic fibrosis (CF) is caused by a mutation in the Cystic fibrosis transmembrane conductance regulator (CFTR) gene, and features recurrent sinus and pulmonary infections, steatorrhea, and malnutrition. CF is associated with diverse cutaneous manifestations, including transient reactive papulotranslucent acrokeratoderma of the palms, nutrient deficiency dermatoses, and vasculitis. Rarely these are presenting symptoms of CF, prior to pulmonary or gastrointestinal sequelae. Cutaneous drug eruptions are also highly common in patients with CF (PwCF) given frequent antibiotic exposure. Finally, CFTR modulating therapy, which has revolutionized CF management, is associated with cutaneous side effects ranging from acute urticaria to toxic epidermal necrolysis. Recognition of dermatologic clinical manifestations of CF is important to appropriately care for PwCF. Dermatologists may play a significant role in the diagnosis and management of CF and associated skin complications.
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Regulador de Condutância Transmembrana em Fibrose Cística , Fibrose Cística , Humanos , Fibrose Cística/complicações , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Dermatopatias/etiologia , Dermatopatias/diagnóstico , Toxidermias/etiologia , Toxidermias/diagnóstico , Antibacterianos/uso terapêuticoRESUMO
Cryptococcus neoformans is an opportunistic fungal pathogen whose pathogenic lifestyle is linked to its ability to cope with fluctuating levels of copper (Cu), an essential metal involved in multiple virulence mechanisms, within distinct host niches. During lethal cryptococcal meningitis in the brain, C. neoformans senses a Cu-deficient environment and is highly dependent on its ability to scavenge trace levels of Cu from its host and adapt to Cu scarcity to successfully colonize this niche. In this study, we demonstrate for this critical adaptation, the Cu-sensing transcription factor Cuf1 differentially regulates the expression of the SOD1 and SOD2 superoxide dismutases in novel ways. Genetic and transcriptional analysis reveals Cuf1 specifies 5'-truncations of the SOD1 and SOD2 mRNAs through specific binding to Cu responsive elements within their respective promoter regions. This results in Cuf1-dependent repression of the highly abundant SOD1 and simultaneously induces expression of two isoforms of SOD2, the canonical mitochondrial targeted isoform and a novel alternative cytosolic isoform, from a single alternative transcript produced specifically under Cu limitation. The generation of cytosolic Sod2 during Cu limitation is required to maintain cellular antioxidant defense against superoxide stress both in vitro and in vivo. Further, decoupling Cuf1 regulation of Sod2 localization compromises the ability of C. neoformans to colonize organs in murine models of cryptococcosis. Our results provide a link between transcription factor-mediated alteration of protein localization and cell proliferation under stress, which could impact tissue colonization by a fungal pathogen.
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Cryptococcus neoformans/enzimologia , Proteínas Fúngicas/metabolismo , Superóxido Dismutase-1/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Transcrição/metabolismo , Animais , Cobre/metabolismo , Cryptococcus neoformans/genética , Cryptococcus neoformans/isolamento & purificação , Modelos Animais de Doenças , Feminino , Proteínas Fúngicas/genética , Masculino , Camundongos , Isoformas de Proteínas , Frações Subcelulares/metabolismo , Superóxido Dismutase/genética , Superóxido Dismutase-1/genéticaRESUMO
Fungal cells colonize and proliferate in distinct niches, from soil and plants to diverse tissues in human hosts. Consequently, fungi are challenged with the goal of obtaining nutrients while simultaneously elaborating robust regulatory mechanisms to cope with a range of availability of nutrients, from scarcity to excess. Copper is essential for life but also potentially toxic. In this review we describe the sophisticated homeostatic mechanisms by which fungi acquire, utilize, and control this biochemically versatile trace element. Fungal pathogens, which can occupy distinct host tissues that have their own intrinsic requirements for copper homeostasis, have evolved mechanisms to acquire copper to successfully colonize the host, disseminate to other tissues, and combat host copper bombardment mechanisms that would otherwise mitigate virulence.
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Cobre/metabolismo , Fungos/metabolismo , Oligoelementos/metabolismo , HomeostaseRESUMO
Infection by the fungal pathogen Cryptococcus neoformans causes lethal meningitis, primarily in immune-compromised individuals. Colonization of the brain by C. neoformans is dependent on copper (Cu) acquisition from the host, which drives critical virulence mechanisms. While C. neoformans Cu+ import and virulence are dependent on the Ctr1 and Ctr4 proteins, little is known concerning extracellular Cu ligands that participate in this process. We identified a C. neoformans gene, BIM1, that is strongly induced during Cu limitation and which encodes a protein related to lytic polysaccharide monooxygenases (LPMOs). Surprisingly, bim1 mutants are Cu deficient, and Bim1 function in Cu accumulation depends on Cu2+ coordination and cell-surface association via a glycophosphatidyl inositol anchor. Bim1 participates in Cu uptake in concert with Ctr1 and expression of this pathway drives brain colonization in mouse infection models. These studies demonstrate a role for LPMO-like proteins as a critical factor for Cu acquisition in fungal meningitis.
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Cobre/metabolismo , Cryptococcus neoformans/metabolismo , Oxigenases de Função Mista/metabolismo , Animais , Criptococose/metabolismo , Cryptococcus neoformans/patogenicidade , Modelos Animais de Doenças , Feminino , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Meningite/metabolismo , Meningite/fisiopatologia , Camundongos , Camundongos Endogâmicos A , Polissacarídeos/metabolismo , VirulênciaRESUMO
The spliceosome is a large ribonucleoprotein complex that removes introns from pre-mRNAs. At its functional core lies the essential pre-mRNA processing factor 8 (Prp8) protein. Across diverse eukaryotes, this protein cofactor of RNA catalysis harbors a self-splicing element called an intein. Inteins in Prp8 are extremely pervasive and are found at 7 different sites in various species. Here, we focus on the Prp8 intein from Cryptococcus neoformans (Cne), a human fungal pathogen. We solved the crystal structure of this intein, revealing structural homology among protein splicing sequences in eukaryotes, including the Hedgehog C terminus. Working with the Cne Prp8 intein in a reporter assay, we find that the biologically relevant divalent metals copper and zinc inhibit intein splicing, albeit by 2 different mechanisms. Copper likely stimulates reversible modifications on a catalytically important cysteine, whereas zinc binds at the terminal asparagine and the same critical cysteine. Importantly, we also show that copper treatment inhibits Prp8 protein splicing in Cne. Lastly, an intein-containing Prp8 precursor model is presented, suggesting that metal-induced protein splicing inhibition would disturb function of both Prp8 and the spliceosome. These results indicate that Prp8 protein splicing can be modulated, with potential functional implications for the spliceosome.
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Cryptococcus neoformans/genética , Proteínas Fúngicas/genética , Splicing de RNA , Proteínas de Ligação a RNA/genética , Spliceossomos/metabolismo , Asparagina/química , Asparagina/metabolismo , Sítios de Ligação , Clonagem Molecular , Cobre/química , Cobre/metabolismo , Cryptococcus neoformans/metabolismo , Cristalografia por Raios X , Cisteína/química , Cisteína/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Expressão Gênica , Genes Reporter , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Inteínas , Proteínas Ligantes de Maltose/genética , Proteínas Ligantes de Maltose/metabolismo , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de Sequência , Spliceossomos/ultraestrutura , Homologia Estrutural de Proteína , Zinco/química , Zinco/metabolismoRESUMO
Tok-tokkies are one of the most iconic lineages within Tenebrionidae. In addition to containing some of the largest darkling beetles, this tribe is recognized for its remarkable form of sexual communication known as substrate tapping. Nevertheless, the phylogenetic relationships within the group remain poorly understood. This study investigates the usefulness of female terminalia morphology for delimiting Sepidiini and reconstructing relationships among it. Data on the structure of the ovipositors, genital tubes and spicula ventrali have been generated for >200 species representing 28 Pimeliinae tribes. This dataset was used in a comparative analysis at the subfamilial level, which resulted in recognition of several unique features of tok-tokkie terminalia. Additionally, new features linking phenotypically challenging tribes also were recovered (Cryptochilini + Idisiini + Pimeliini). Secondly, 23 characters linked to the structure of female terminalia were defined for tok-tok beetles. Cladistic analysis demonstrates the nonmonophyletic nature of most of the recognized subtribes. The morphological dataset was analysed separately and in combination with available molecular data (CAD, Wg, cox1, cox2, 28S). All obtained topologies were largely congruent, supporting the following changes: Palpomodina Kaminski & Gearner subtr.n. is erected to accommodate the genera Namibomodes and Palpomodes; Argenticrinis and Bombocnodulus are transferred from Hypomelina to Molurina; 153 species and subspecies previously classified within Psammodes are distributed over three separate genera (Mariazofia Kaminski nom.n., Piesomera stat.r., Psammodes sens.n.). Psammodes sklodowskae Kaminski & Gearner sp.n. is described. Preliminary investigation of the ovipositor of Mariazofia basuto (Koch) comb.n. was carried out with the application of microcomputed tomography, illuminating the muscular system as a reliable reference point for recognizing homologous elements in highly modified ovipositors.
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Besouros , Animais , Feminino , Filogenia , Microtomografia por Raio-X , Sorogrupo , GenitáliaRESUMO
The ability of the human fungal pathogen Cryptococcus neoformans to adapt to variable copper (Cu) environments within the host is key for successful dissemination and colonization. During pulmonary infection, host alveolar macrophages compartmentalize Cu into the phagosome and C. neoformans Cu-detoxifying metallothioneins, MT1 and MT2, are required for survival of the pathogen. In contrast, during brain colonization the C. neoformans Cu+ importers Ctr1 and Ctr4 are required for virulence. Central for the regulation and expression of both the Cu detoxifying MT1/2 and the Cu acquisition Ctr1/4 proteins is the Cu-metalloregulatory transcription factor Cuf1, an established C. neoformans virulence factor. Due to the importance of the distinct C. neoformans Cu homeostasis mechanisms during host colonization and virulence, and to the central role of Cuf1 in regulating Cu homeostasis, we performed a combination of RNA-Seq and ChIP-Seq experiments to identify differentially transcribed genes between conditions of high and low Cu. We demonstrate that the transcriptional regulation exerted by Cuf1 is intrinsically complex and that Cuf1 also functions as a transcriptional repressor. The Cu- and Cuf1-dependent regulon in C. neoformans reveals new adaptive mechanisms for Cu homeostasis in this pathogenic fungus and identifies potential new pathogen-specific targets for therapeutic intervention in fungal infections.
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Cobre/metabolismo , Criptococose/microbiologia , Cryptococcus neoformans/genética , Proteínas Fúngicas/metabolismo , Fatores de Transcrição/metabolismo , Animais , Sequência de Bases , Cryptococcus neoformans/patogenicidade , Cryptococcus neoformans/fisiologia , Proteínas Fúngicas/genética , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica/genética , Estudo de Associação Genômica Ampla , Humanos , RNA Fúngico , Fatores de Transcrição/genética , Virulência/genéticaRESUMO
Pseudomonas aeruginosa PAO1 encodes two outer membrane receptors, PhuR (Pseudomonas heme uptake) and HasR (heme assimilation system). The HasR and PhuR receptors have distinct heme coordinating ligands and substrate specificities. HasR is encoded in an operon with a secreted hemophore, HasAp. In contrast the non-hemophore-dependent PhuR is encoded within an operon along with proteins required for heme translocation into the cytoplasm. Herein we report on the contributions of the HasR and PhuR receptors to heme uptake and utilization. Employing bacterial genetics and isotopic [(13)C]heme labeling studies we have shown both PhuR and HasR are required for optimal heme utilization. However, the unique His-Tyr-ligated PhuR plays a major role in the acquisition of heme. In contrast the HasR receptor plays a primary role in the sensing of extracellular heme and a supplementary role in heme uptake. We propose PhuR and HasR represent non-redundant heme receptors, capable of accessing heme across a wide range of physiological conditions on colonization of the host.
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Proteínas da Membrana Bacteriana Externa/metabolismo , Heme/metabolismo , Pseudomonas aeruginosa/metabolismo , Proteínas da Membrana Bacteriana Externa/química , Heme/química , Modelos MolecularesRESUMO
Pseudomonas aeruginosa PAO1 encodes two outer membrane receptors, PhuR (Pseudomonas heme uptake) and HasR (heme assimilation system). The HasR receptor acquires heme through interaction with a secreted hemophore, HasAp. The non-hemophore-dependent PhuR is encoded along with proteins required for heme translocation into the cytoplasm. Herein, we report the isolation and characterization of the HasR and PhuR receptors. Absorption and MCD spectroscopy confirmed that, similar to other Gram-negative OM receptors, HasR coordinates heme through the conserved N-terminal plug His-221 and His-624 of the surface-exposed FRAP-loop. In contrast, PhuR showed distinct absorption and MCD spectra consistent with coordination through a Tyr residue. Sequence alignment of PhuR with all known Gram-negative OM heme receptors revealed a lack of a conserved His within the FRAP loop but two Tyr residues at positions 519 and 529. Site-directed mutagenesis and spectroscopic characterization confirmed Tyr-519 and the N-terminal plug His-124 provide the heme ligands in PhuR. We propose that PhuR and HasR represent nonredundant heme receptors capable of sensing and accessing heme across a wide range of physiological conditions on colonization and infection of the host.
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Proteínas da Membrana Bacteriana Externa/química , Proteínas de Transporte/química , Heme/química , Pseudomonas aeruginosa/química , Sequência de Aminoácidos , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Heme/metabolismo , Mutagênese Sítio-Dirigida , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Alinhamento de SequênciaRESUMO
The asidine darkling beetles (Coleoptera: Tenebrionidae: Asidini) are a diverse tribe of flightless tenebrionids found in many arid and sub-arid habitats around the world. The 263 currently described North American species are contained in ten genera, all of which are restricted to the western half of the continent. The Asidini, like all members of the subfamily Pimeliinae, lack defensive glands. Instead, several phenotypic traits occur within the tribe that may help limit predation. These include the contrasting defensive strategies of crypsis, through either background matching or pattern disruption, and Batesian mimicry of the chemically defended genus Eleodes. Dorsal elytral morphology was assessed between 53 North American asidine species and 13 common Eleodes model species using multiple methodologies to assess similarities between species in the two groups that might indicate mimetic relationships. A phylogeny of the North American asidines is used to map the occurrence of differing defensive strategies within the tribe. Crypsis is reconstructed as the ancestral state, with two origins for Batesian mimicry and multiple reversals. The combination of strongly to weakly cryptic species and varying levels of mimetic fidelity to Eleodes model species make the asidines a promising lineage upon which to further explore the evolution of defensive phenotypes.
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BACKGROUND: Iron deficiency is highly prevalent in people with cystic fibrosis (PwCF). While elexacaftor/tezacaftor/ivacaftor (ETI) has shown remarkable improvements in respiratory symptoms in PwCF, the effect of ETI on iron status remains unknown. This study aims to identify the effect of ETI on iron status in PwCF. METHODS: A single-center retrospective cohort study of 127 adult PwCF was conducted to assess the impact of ETI on iron, ferritin, transferrin levels, and percent saturation of transferrin (PSAT). Data were collected from the electronic medical record from January 2017 to September 2022, encompassing 2 years before and after ETI initiation. The primary outcome was serum iron parameters: iron, ferritin, transferrin, and PSAT levels following ETI treatment. Secondary outcomes analyzed iron supplementation. Univariate and multivariate mixed-effects models were used for the analysis of ETI. RESULTS: After adjusting for covariates, following ETI initiation, the mean iron level increased by 20.24 µg/dL (p < .001), ferritin levels were 31.4% (p < .001) higher, PSAT showed a 5.09 percentage point increase (p < .001), and transferrin levels increased by 2.71 mg/dL (p = .439). Patients with and without iron supplementation experienced a significant increase in iron after ETI (p < .001). CONCLUSIONS: ETI is associated with a significant increase in iron, ferritin, and PSAT levels. Patients with and without iron supplementation demonstrated a significant increase in iron. This study shows the benefits of ETI on iron status in PwCF. However, further translational studies are required to understand the impact of ETI on iron absorption and metabolism in PwCF.
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Fibrose Cística , Indóis , Ferro , Pirazóis , Piridinas , Pirrolidinas , Quinolonas , Adulto , Humanos , Fibrose Cística/complicações , Fibrose Cística/tratamento farmacológico , Estudos Retrospectivos , Ferritinas , Transferrinas , Regulador de Condutância Transmembrana em Fibrose Cística , Mutação , Aminofenóis/uso terapêutico , Benzodioxóis/uso terapêuticoRESUMO
Synthetic biology is touted as the next industrial revolution as it promises access to greener biocatalytic syntheses to replace many industrial organic chemistries. Here, it is shown to what synthetic biology can offer in the form of multienzyme cascades for the synthesis of the most basic of new materials-chemicals, including especially designer chemical products and their analogs. Since achieving this is predicated on dramatically expanding the chemical space that enzymes access, such chemistry will probably be undertaken in cell-free or minimalist formats to overcome the inherent toxicity of non-natural substrates to living cells. Laying out relevant aspects that need to be considered in the design of multi-enzymatic cascades for these purposes is begun. Representative multienzymatic cascades are critically reviewed, which have been specifically developed for the synthesis of compounds that have either been made only by traditional organic synthesis along with those cascades utilized for novel compound syntheses. Lastly, an overview of strategies that look toward exploiting bio/nanomaterials for accessing channeling and other nanoscale materials phenomena in vitro to direct novel enzymatic biosynthesis and improve catalytic efficiency is provided. Finally, a perspective on what is needed for this field to develop in the short and long term is presented.
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Nanoestruturas , Biocatálise , CatáliseRESUMO
Melanin is one of the most abundant natural biomolecules on Earth. These macromolecular biopolymers display several unique physical and chemical properties and have garnered interest as biomaterials for various commercial and industrial applications. To this end, extensive research has gone into refining methods for the synthesis and extraction of melanin from natural and recombinant sources. In this study, we developed and refined a procedure using a recombinant microbial system for the biosynthesis of melanin using the tyrosinase enzyme Tyr1 and tyrosine as a substrate. Using the emergent microbial chassis organisms Vibrio natriegens, we achieved maximal yields of 7.57 g/L, and one of the highest reported volumetric productivities of 473 mg L-1 h-1 with 100% conversion rates in an optimized, minimally defined medium. Additionally, we identified and investigated the use of a native copper responsive promoter in V. natriegens for stringent regulation of heterologous protein expression as a cost effective alternative to traditional IPTG-based induction. This research represents a promising advancement towards a green, rapid, and economical alternative for the biomanufacture of melanin.
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All Gram-negative bacteria are believed to produce outer membrane vesicles (OMVs), proteoliposomes shed from the outermost membrane. We previously separately engineered E. coli to produce and package two organophosphate (OP) hydrolyzing enzymes, phosphotriesterase (PTE) and diisopropylfluorophosphatase (DFPase), into secreted OMVs. From this work, we realized a need to thoroughly compare multiple packaging strategies to elicit design rules for this process, focused on (1) membrane anchors or periplasm-directing proteins (herein "anchors/directors") and (2) the linkers connecting these to the cargo enzyme; both may affect enzyme cargo activity. Herein, we assessed six anchors/directors to load PTE and DFPase into OMVs: four membrane anchors, namely, lipopeptide Lpp', SlyB, SLP, and OmpA, and two periplasm-directing proteins, namely, maltose-binding protein (MBP) and BtuF. To test the effect of linker length and rigidity, four different linkers were compared using the anchor Lpp'. Our results showed that PTE and DFPase were packaged with most anchors/directors to different degrees. For the Lpp' anchor, increased packaging and activity corresponded to increased linker length. Our findings demonstrate that the selection of anchors/directors and linkers can greatly influence the packaging and bioactivity of enzymes loaded into OMVs, and these findings have the potential to be utilized for packaging other enzymes into OMVs.
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In bacteria, the fine balance of maintaining adequate iron levels while preventing the deleterious effects of excess iron has led to the evolution of sophisticated cellular mechanisms to obtain, store, and regulate iron. Iron uptake provides a significant challenge given its limited bioavailability and need to be transported across the bacterial cell wall and membranes. Pathogenic bacteria have circumvented the iron-availability issue by utilizing the hosts' heme-containing proteins as a source of iron. Once internalized, iron is liberated from the porphyrin enzymatically for cellular processes within the bacterial cell. Heme, a lipophilic and toxic molecule, poses a significant challenge in terms of transport given its chemical reactivity. As such, pathogenic bacteria have evolved sophisticated membrane transporters to coordinate, sequester, and transport heme. Recent advances in the biochemical and structural characterization of the membrane-bound heme transport proteins are discussed in the context of ligand coordination, protein-protein interaction, and heme transfer.
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Bactérias/metabolismo , Membrana Celular/metabolismo , Parede Celular/metabolismo , Heme/metabolismo , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Transporte Biológico , Ferro/química , Ferro/metabolismo , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Metaloporfirinas/química , Metaloporfirinas/farmacologia , Receptores de Superfície Celular/antagonistas & inibidores , Receptores de Superfície Celular/metabolismoRESUMO
The study of ancient DNA is revolutionizing our understanding of paleo-ecology and the evolutionary history of species. Insects are essential components in many ecosystems and constitute the most diverse group of animals. Yet they are largely neglected in ancient DNA studies. We report the results of the first targeted investigation of insect ancient DNA to positively identify subfossil insects to species, which includes the recovery of endogenous content from samples as old as ~ 34,355 ybp. Potential inhibitors currently limiting widespread research on insect ancient DNA are discussed, including the lack of closely related genomic reference sequences (decreased mapping efficiency) and the need for more extensive collaborations with insect taxonomists. The advantages of insect-based studies are also highlighted, especially in the context of understanding past climate change. In this regard, insect remains from ancient packrat middens are a rich and largely uninvestigated resource for exploring paleo-ecology and species dynamics over time.
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Artrópodes/genética , DNA Antigo/análise , Análise de Sequência de DNA/veterinária , Sigmodontinae/parasitologia , Animais , DNA Mitocondrial/genética , Fósseis , Biblioteca Gênica , Sequenciamento de Nucleotídeos em Larga Escala , RNA Ribossômico 28S/genética , Sigmodontinae/genéticaRESUMO
The darkling beetle genus Hypogena Dejean, 1834 (Tenebrionidae: Tenebrioninae) is revised. Hypogena is entirely composed of dorsoventrally flattened species that live subcortically in dead trees. This genus is generally identified by male specific characters, particularly the presence of cephalic horns. Hypogena is currently placed within the tribe Triboliini Gistel, 1848. However, several previously overlooked morphological characters call into question its placement within the tribe. A morphological matrix of 94 external adult characters was assembled to examine species relationships and boundaries. The resulting phylogeny is presented. Thirteen Hypogena species were previously recognized as valid, including Hypogena marginalis Doyen Poinar from Dominican amber. Four previously unidentified species are described in this study: Hypogena akuma sp. nov. (Brazil), Hypogena cryptica sp. nov. (Mexico), Hypogena hirsuta sp. nov. (Ecuador), and Hypogena reburra sp. nov. (Colombia). Lectotypes are designated for Hypogena depressa (Champion, 1886), Hypogena dejeani (Champion, 1886), Hypogena canaliculata (Champion, 1886), and Hypogena vacca (Fabricius, 1801). A neotype is designated for Tenebrio biimpressus (Latreille, 1833) (type species of Hypogena, synonymized under Hypogena brasilica (Perty)) in order to maintain stability within the genus.