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1.
Chem Commun (Camb) ; 59(93): 13843-13846, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37921487

RESUMO

An NAD+ featuring an adenosyl 4'-azido functions as a general substrate for poly-ADP-ribose polymerases. Its derived mono- and poly-ADP-ribosylated proteins can be adequately recognized by distinct ADP-ribosylation-specific readers. This molecule represents the first ribose-functionalized NAD+ with versatile activities across different ADP-ribosyltransferases and provides insight into developing new probes for ADP-ribosylation.


Assuntos
NAD , Ribose , NAD/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , ADP Ribose Transferases/química , ADP Ribose Transferases/genética , ADP Ribose Transferases/metabolismo , ADP-Ribosilação
2.
Chem Sci ; 14(40): 11022-11032, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37860661

RESUMO

Aspergillus fumigatus is a serious human pathogen causing life-threatening Aspergillosis in immunocompromised patients. Secondary metabolites (SMs) play an important role in pathogenesis, but the products of many SM biosynthetic gene clusters (BGCs) remain unknown. In this study, we have developed a heterologous expression platform in Aspergillus nidulans, using a newly created genetic dereplication strain, to express a previously unknown BGC from A. fumigatus and determine its products. The BGC produces sartorypyrones, and we have named it the spy BGC. Analysis of targeted gene deletions by HRESIMS, NMR, and microcrystal electron diffraction (MicroED) enabled us to identify 12 products from the spy BGC. Seven of the compounds have not been isolated previously. We also individually expressed the polyketide synthase (PKS) gene spyA and demonstrated that it produces the polyketide triacetic acid lactone (TAL), a potentially important biorenewable platform chemical. Our data have allowed us to propose a biosynthetic pathway for sartorypyrones and related natural products. This work highlights the potential of using the A. nidulans heterologous expression platform to uncover cryptic BGCs from A. fumigatus and other species, despite the complexity of their secondary metabolomes.

3.
ACS Omega ; 8(19): 16713-16721, 2023 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-37214671

RESUMO

Filamentous fungi are an essential source of bioactive mycotoxins. Recent efforts have focused on developing antifungal agents that are effective against invasive yeasts, such as Candida spp. By screening fungal strains isolated from regions surrounding the Chernobyl nuclear power plant disaster for antifungal activity against Candida albicans, we found that Aspergillus melleus IMV 01140 produced compounds that inhibited the growth of the yeast. The active compound produced by A. melleus was isolated and found to be neoaspergillic acid, a compound that is closely related to aspergillic acid. While aspergillic acid and its derivatives have been characterized and were found to have antibacterial and antifungal properties, neoaspergillic acid has been much less studied. Even though neoaspergillic acid and related compounds were found to have antibacterial and antitumoral effects, further investigation into this group of compounds is limited by challenges associated with large-scale production, isolation, and purification. The production of neoaspergillic acid has been shown to require co-cultivation methods or special growth conditions. In this work, neoaspergillic acid and related compounds were found to be produced by A. melleus under laboratory growth conditions. The biosynthetic gene cluster of neoaspergillic acid was predicted using the aspergillic acid gene cluster as a model. The biosynthetic pathway for neoaspergillic acid was then confirmed by establishing an in vitro CRISPR-ribonucleoprotein system to individually delete genes within the cluster. A negative transcriptional factor, mcrA, was also eliminated to further improve the production of neoaspergillic acid and the related compounds for future studies.

4.
J Am Chem Soc ; 145(9): 5222-5230, 2023 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-36779837

RESUMO

Polystyrene (PS) is one of the most used yet infrequently recycled plastics. Although manufactured on the scale of 300 million tons per year globally, current approaches toward PS degradation are energy- and carbon-inefficient, slow, and/or limited in the value that they reclaim. We recently reported a scalable process to degrade post-consumer polyethylene-containing waste streams into carboxylic diacids. Engineered fungal strains then upgrade these diacids biosynthetically to synthesize pharmacologically active secondary metabolites. Herein, we apply a similar reaction to rapidly convert PS to benzoic acid in high yield. Engineered strains of the filamentous fungus Aspergillus nidulans then biosynthetically upgrade PS-derived crude benzoic acid to the structurally diverse secondary metabolites ergothioneine, pleuromutilin, and mutilin. Further, we expand the catalog of plastic-derived products to include spores of the industrially relevant biocontrol agent Aspergillus flavus Af36 from crude PS-derived benzoic acid.


Assuntos
Produtos Biológicos , Poliestirenos , Poliestirenos/metabolismo , Produtos Biológicos/metabolismo , Plásticos/metabolismo , Polietileno/metabolismo , Aspergillus flavus/metabolismo
5.
J Trauma Acute Care Surg ; 94(6): 798-802, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36805626

RESUMO

BACKGROUND: Trauma-induced coagulopathy (TIC) has been the subject of intense study for greater than a century, and it is associated with high morbidity and mortality. The Trans-Agency Consortium for Trauma-Induced Coagulopathy, funded by the National Health Heart, Lung and Blood Institute, was tasked with developing a clinical TIC score, distinguishing between injury-induced bleeding from persistent bleeding due to TIC. We hypothesized that the Trans-Agency Consortium for Trauma-Induced Coagulopathy clinical TIC score would correlate with laboratory measures of coagulation, transfusion requirements, and mortality. METHODS: Trauma activation patients requiring a surgical procedure for hemostasis were scored in the operating room (OR) and in the first ICU day by the attending trauma surgeon. Conventional and viscoelastic (thrombelastography) coagulation assays, transfusion requirements, and mortality were correlated to the coagulation scores using the Cochran-Armitage trend test or linear regression for numerical variables. RESULTS: Increased OR TIC scores were significantly associated with abnormal conventional and viscoelastic measurements, including hyperfibrinolysis incidence, as well as with higher mortality and more frequent requirement for massive transfusion ( p < 0.0001 for all trends). Patients with OR TIC score greater than 3 were more than 31 times more likely to have an ICU TIC score greater than 3 (relative risk, 31.6; 95% confidence interval, 12.7-78.3; p < 0.0001). CONCLUSION: A clinically defined TIC score obtained in the OR reflected the requirement for massive transfusion and mortality in severely injured trauma patients and also correlated with abnormal coagulation assays. The OR TIC score should be validated in multicenter studies. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.


Assuntos
Transtornos da Coagulação Sanguínea , Ferimentos e Lesões , Humanos , Transtornos da Coagulação Sanguínea/diagnóstico , Transtornos da Coagulação Sanguínea/etiologia , Coagulação Sanguínea , Hemorragia/etiologia , Hemostasia , Testes de Coagulação Sanguínea , Tromboelastografia/métodos , Ferimentos e Lesões/complicações
6.
Angew Chem Int Ed Engl ; 62(4): e202214609, 2023 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-36417558

RESUMO

Waste plastics represent major environmental and economic burdens due to their ubiquity, slow breakdown rates, and inadequacy of current recycling routes. Polyethylenes are particularly problematic, because they lack robust recycling approaches despite being the most abundant plastics in use today. We report a novel chemical and biological approach for the rapid conversion of polyethylenes into structurally complex and pharmacologically active compounds. We present conditions for aerobic, catalytic digestion of polyethylenes collected from post-consumer and oceanic waste streams, creating carboxylic diacids that can then be used as a carbon source by the fungus Aspergillus nidulans. As a proof of principle, we have engineered strains of A. nidulans to synthesize the fungal secondary metabolites asperbenzaldehyde, citreoviridin, and mutilin when grown on these digestion products. This hybrid approach considerably expands the range of products to which polyethylenes can be upcycled.


Assuntos
Aspergillus nidulans , Polietilenos , Polietilenos/química , Plásticos/química , Catálise , Aspergillus nidulans/metabolismo
7.
JSLS ; 26(3)2022.
Artigo em Inglês | MEDLINE | ID: mdl-36212183

RESUMO

Introduction: Many patients utilize the Emergency Room (ER) for primary care, resulting in overburdened ERs, strained resources, and delays in care. To combat this, many centers have adopted a Trauma/Acute Care Surgery (TACS) service providing specialty surgeons whose primary work is the unencumbered surgical availability to emergency surgery patients. To evaluate our programs' efficacy, we investigated cholecystectomies as a common urgent procedure representative of services provided. We hypothesized that the adoption of a TACS service would result in improved access to care as evidence by decreased ER visits prior to cholecystectomy, improved time to cholecystectomy, and decreased hospital length of stay (LOS). Methods: All patients that underwent urgent cholecystectomy from January 1, 2018 to December 31, 2018 were reviewed. The unencumbered TACS surgeon was implemented on July 1, 2018. Prior ER visits involving biliary symptoms, time from admission to cholecystectomy, and hospital LOS were compared. Results: Of the 322 urgent cholecystectomies over the study period, 165 were performed prior and 157 following adoption of the TACS structure. The average number of ER visits for biliary symptoms prior to cholecystectomy decreased from 1.4 to 1.2 (p = 0.01). Time from admission to cholecystectomy was 28.3 hours and 27.3 hours respectively (p = 0.74). Average LOS decreased following the restructure (3.1 vs 2.5 days; p = 0.03). Conclusion: Implementation of an unencumbered TACS surgeon managing urgent surgical disease improves access to and delivery of surgical services for cholecystectomy patients in a safety net, level one trauma center. Further research is necessary to determine potential improvements in hospital cost and patient satisfaction.


Assuntos
Colecistectomia Laparoscópica , Cirurgiões , Colecistectomia/métodos , Serviço Hospitalar de Emergência , Humanos , Tempo de Internação , Estudos Retrospectivos , Resultado do Tratamento
8.
ACS Chem Biol ; 17(10): 2828-2835, 2022 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-36197945

RESUMO

Genome sequencing of filamentous fungi has demonstrated that most secondary metabolite biosynthetic gene clusters (BGCs) are silent under standard laboratory conditions. In this work, we have established an in vitro CRISPR-Cas9 system in Aspergillus wentii. To activate otherwise silent BGCs, we deleted the negative transcriptional regulator mcrA. Deletion of mcrA (mcrAΔ) resulted in differential production of 17 SMs in total when the strain was cultivated on potato dextrose media (PDA). Nine out of fifteen of these SMs were fully characterized, including emodin (1), physcion (2), sulochrin (3), physcion bianthrone (4), 14-O-demethylsulochrin (5), (trans/cis)-emodin bianthrone (6 and 7), and (trans/cis)-emodin physcion bianthrone (8 and 9). These compounds were all found to be produced by the same polyketide synthase (PKS) BGC. We then performed a secondary knockout targeting this PKS cluster in the mcrAΔ background. The metabolite profile of the dual-knockout strain revealed new metabolites that were not previously detected in the mcrAΔ parent strain. Two additional SMs were purified from the dual-knockout strain and were characterized as aspergillus acid B (16) and a structurally related but previously unidentified compound (17). For the first time, this work presents a facile genetic system capable of targeted gene editing in A. wentii. This work also illustrates the utility of performing a dual knockout to eliminate major metabolic products, enabling additional SM discovery.


Assuntos
Emodina , Aspergillus/genética , Sistemas CRISPR-Cas/genética , Glucose , Família Multigênica , Policetídeo Sintases/genética , Ribonucleoproteínas
9.
J Nat Prod ; 85(10): 2484-2518, 2022 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-36173392

RESUMO

Fungal natural products comprise a wide range of bioactive compounds including important drugs and agrochemicals. Intriguingly, bioinformatic analyses of fungal genomes have revealed that fungi have the potential to produce significantly more natural products than what have been discovered so far. It has thus become widely accepted that most biosynthesis pathways of fungal natural products are silent or expressed at very low levels under laboratory cultivation conditions. To tap into this vast chemical reservoir, the reconstitution of entire biosynthetic pathways in genetically tractable fungal hosts (total heterologous biosynthesis) has become increasingly employed in recent years. This review summarizes total heterologous biosynthesis of fungal natural products accomplished before 2020 using Aspergillus nidulans as heterologous hosts. We review here Aspergillus transformation, A. nidulans hosts, shuttle vectors for episomal expression, and chromosomal integration expression. These tools, collectively, not only facilitate the discovery of cryptic natural products but can also be used to generate high-yield strains with clean metabolite backgrounds. In comparison with total synthesis, total heterologous biosynthesis offers a simplified strategy to construct complex molecules and holds potential for commercial application.


Assuntos
Aspergillus nidulans , Produtos Biológicos , Aspergillus nidulans/genética , Aspergillus nidulans/metabolismo , Produtos Biológicos/metabolismo , Genes Fúngicos , Vias Biossintéticas , Genoma Fúngico , Família Multigênica
10.
Am J Surg ; 224(6): 1374-1379, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35940931

RESUMO

BACKGROUND: Patients suspected of syncope frequently undergo laboratory and imaging studies to determine the etiology of the syncope. Variability exists in these workups across institutions. The purpose of this study was to evaluate the utilization and diagnostic yield of these workups and the patient characteristics associated with syncopal falls. METHODS: A multi-institutional retrospective review was performed on adult patients admitted after a fall between 1/2017-12/2018. Syncopal falls were compared to non-syncopal falls. RESULTS: 4478 patients were included. There were 795 (18%) patients with a syncopal fall. Electrocardiogram, troponin, echocardiogram, CT angiography (CTA), and carotid ultrasound were more frequently tested in syncope patients compared to non-syncope patients. Syncope patients had higher rates of positive telemetry/Holter monitoring, CTAs, and electroencephalograms. CONCLUSION: Patients who sustain syncopal falls frequently undergo diagnostic testing without a higher yield to determine the etiology of syncope.


Assuntos
Síncope , Telemetria , Adulto , Humanos , Síncope/diagnóstico , Síncope/etiologia , Telemetria/efeitos adversos , Ecocardiografia , Testes Diagnósticos de Rotina/efeitos adversos
11.
Front Microbiol ; 13: 893071, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35847112

RESUMO

Due to immense phenotypic plasticity and adaptability, Aspergillus niger is a cosmopolitan fungus that thrives in versatile environments, including the International Space Station (ISS). This is the first report of genomic, proteomic, and metabolomic alterations observed in A. niger strain JSC-093350089 grown in a controlled experiment aboard the ISS. Whole-genome sequencing (WGS) revealed that ISS conditions, including microgravity and enhanced irradiation, triggered non-synonymous point mutations in specific regions, chromosomes VIII and XII of the JSC-093350089 genome when compared to the ground-grown control. Proteome analysis showed altered abundance of proteins involved in carbohydrate metabolism, stress response, and cellular amino acid and protein catabolic processes following growth aboard the ISS. Metabolome analysis further confirmed that space conditions altered molecular suite of ISS-grown A. niger JSC-093350089. After regrowing both strains on Earth, production of antioxidant-Pyranonigrin A was significantly induced in the ISS-flown, but not the ground control strain. In summary, the microgravity and enhanced irradiation triggered unique molecular responses in the A. niger JSC-093350089 suggesting adaptive responses.

12.
Fungal Genet Biol ; 160: 103694, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35398258

RESUMO

Filamentous fungal secondary metabolites are an important source of bioactive components. Genome sequencing ofAspergillus terreusrevealed many silent secondary metabolite biosynthetic gene clusters presumed to be involved in producing secondary metabolites. Activation of silent gene clusters through overexpressing a pathway-specific regulator is an effective avenue for discovering novel fungal secondary metabolites. Replacement of the native promoter of the pathway-specific activator with the inducible Tet-on system to activate thetazpathway led to the discovery of a series of azaphilone secondary metabolites, among which azaterrilone A (1) was purified and identified for the first time. Genetic deletion of core PKS genes and transcriptional analysis further characterized thetazgene cluster to consist of 16 genes with the NR-PKS and the HR-PKS collaborating in a convergent mode. Based on the putative gene functions and the characterized compounds structural information, a biosynthetic pathway of azaterrilone A (1) was proposed.


Assuntos
Aspergillus , Família Multigênica , Aspergillus/genética , Aspergillus/metabolismo , Benzopiranos , Pigmentos Biológicos/genética , Pigmentos Biológicos/metabolismo , Policetídeo Sintases/genética , Policetídeo Sintases/metabolismo
13.
J Fungi (Basel) ; 8(2)2022 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-35205919

RESUMO

Multiple strains of a novel yeast belonging to genus Naganishia were isolated from environmental surfaces aboard the International Space Station (ISS). These strains exhibited a phenotype similar to Titan cell (~10 µm diameter) morphology when grown under a combination of simulated microgravity and 5% CO2 conditions. Confocal, scanning, and transmission electron microscopy revealed distinct morphological differences between the microgravity-grown cells and the standard Earth gravity-grown cells, including larger cells and thicker cell walls, altered intracellular morphology, modifications to extracellular fimbriae, budding, and the shedding of bud scars. Phylogenetic analyses via multi-locus sequence typing indicated that these ISS strains represented a single species in the genus Naganishia and were clustered with Naganishia diffluens. The name Naganishia tulchinskyi is proposed to accommodate these strains, with IF6SW-B1T as the holotype. The gene ontologies were assigned to the cell morphogenesis, microtubule-based response, and response to UV light, suggesting a variety of phenotypes that are well suited to respond to microgravity and radiation. Genomic analyses also indicated that the extracellular region, outer membrane, and cell wall were among the highest cellular component results, thus implying a set of genes associated with Titan-like cell plasticity. Finally, the highest molecular function matches included cytoskeletal motor activity, microtubule motor activity, and nuclear export signal receptor activity.

14.
Microbiol Spectr ; 10(1): e0199421, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35019675

RESUMO

In an ongoing microbial tracking investigation of the International Space Station (ISS), several Sphingomonas strains were isolated. Based on the 16S rRNA gene sequence, phylogenetic analysis identified the ISS strains as Sphingomonas sanguinis (n = 2) and one strain isolated from the Kennedy Space Center cleanroom (used to assemble various Mars mission spacecraft components) as Sphingomonas paucimobilis. Metagenomic sequence analyses of different ISS locations identified 23 Sphingomonas species. An abundance of shotgun metagenomic reads were detected for S. sanguinis in the location from where the ISS strains were isolated. A complete metagenome-assembled genome was generated from the shotgun reads metagenome, and its comparison with the whole-genome sequences (WGS) of the ISS S. sanguinis isolates revealed that they were highly similar. In addition to the phylogeny, the WGS of these Sphingomonas strains were compared with the WGS of the type strains to elucidate genes that can potentially aid in plant growth promotion. Furthermore, the WGS comparison of these strains with the well-characterized Sphingomonas sp. LK11, an arid desert strain, identified several genes responsible for the production of phytohormones and for stress tolerance. Production of one of the phytohormones, indole-3-acetic acid, was further confirmed in the ISS strains using liquid chromatography-mass spectrometry. Pathways associated with phosphate uptake, metabolism, and solubilization in soil were conserved across all the S. sanguinis and S. paucimobilis strains tested. Furthermore, genes thought to promote plant resistance to abiotic stress, including heat/cold shock response, heavy metal resistance, and oxidative and osmotic stress resistance, appear to be present in these space-related S. sanguinis and S. paucimobilis strains. Characterizing these biotechnologically important microorganisms found on the ISS and harnessing their key features will aid in the development of self-sustainable long-term space missions in the future. IMPORTANCESphingomonas is ubiquitous in nature, including the anthropogenically contaminated extreme environments. Members of the Sphingomonas genus have been identified as potential candidates for space biomining beyond earth. This study describes the isolation and identification of Sphingomonas members from the ISS, which are capable of producing the phytohormone indole-3-acetic acid. Microbial production of phytohormones will help future in situ studies, grow plants beyond low earth orbit, and establish self-sustainable life support systems. Beyond phytohormone production, stable genomic elements of abiotic stress resistance, heavy metal resistance, and oxidative and osmotic stress resistance were identified, rendering the ISS Sphingomonas isolate a strong candidate for biotechnology-related applications.


Assuntos
Genômica , Desenvolvimento Vegetal/fisiologia , Sphingomonas/genética , Sphingomonas/isolamento & purificação , Sphingomonas/fisiologia , Ácidos Indolacéticos , Metagenoma , Metagenômica , Filogenia , Desenvolvimento Vegetal/genética , Reguladores de Crescimento de Plantas/genética , RNA Ribossômico 16S , Astronave , Sphingomonas/classificação , Sequenciamento Completo do Genoma
16.
Injury ; 53(5): 1637-1644, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34953578

RESUMO

BACKGROUND: Many centers now perform surgical stabilization of rib fractures (SSRF). This single center study aimed to investigate temporal trends by year in patient selection, operative characteristics, and in-hospital outcomes We hypothesized that, over time, patient selection, time to SSRF, operative time, and in-hospital outcomes varied significantly. METHODS: A retrospective review of a prospectively maintained SSRF database (2010 to 2020) was performed. Patients were stratified by year in which they underwent SSRF. The primary outcome was operative time, defined in minutes from incision to closure. Secondary outcomes were patient and operative characteristics, and in-hospital outcomes. Multivariable regression analyses were performed to assess for temporal trends, corrected for confounders. The outcomes ventilator-, Intensive Care Unit-, and hospital-free days (VFD, IFD, and HFD, respectively) were categorized based on the group's medians, and complications were combined into a composite outcome. RESULTS: In total, 222 patients underwent SSRF on a median of one day after admission (P25-P75, 0-2). Patients had a median age of 54 years (P25-P75, 42-63), ISS of 19 (P25-P75, 13-26), RibScore of 3 (P25-P75, 2-5), and sustained a median of 8 fractured ribs (P25-P75, 6-11). In multivariable analysis, increasing study year was associated with an increase in operative time (p<0.0001). In addition, study year was associated with a significantly reduced odds of complications (Odds ratio [OR], 0.76; 95% Confidence Interval [95% CI], 0.63-0.92; p=0.005), VFD < 28 days (OR, 0.77; 95% CI, 0.65-0.92; p=0.003), IFD < 24 days (OR, 0.77; 95% CI, 0.66-0.91; p=0.002), and HFD < 18 days (OR, 0.64; 95% CI, 0.53-0.76; p<0.0001). CONCLUSION: In-hospital outcomes after SSRF improved over time. Unexpectedly, operative time increased. The reason for this finding is likely multifactorial and may be related to patient selection, onboarding of new surgeons, fracture characteristics, and minimally invasive exposures. Due to potential for confounding, study year should be accounted for when evaluating outcomes of SSRF.


Assuntos
Fraturas das Costelas , Hospitalização , Hospitais , Humanos , Pessoa de Meia-Idade , Seleção de Pacientes , Estudos Retrospectivos , Fraturas das Costelas/complicações , Fraturas das Costelas/cirurgia
17.
J Ind Microbiol Biotechnol ; 48(9-10)2021 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-34415047

RESUMO

Many fungi develop both asexual and sexual spores that serve as propagules for dissemination and/or recombination of genetic traits. Asexual spores are often heavily pigmented and this pigmentation provides protection from UV light. However, little is known about any purpose pigmentation that may serve for sexual spores. The model Ascomycete Aspergillus nidulans produces both green pigmented asexual spores (conidia) and red pigmented sexual spores (ascospores). Here we find that the previously characterized red pigment, asperthecin, is the A. nidulans ascospore pigment. The asperthecin biosynthetic gene cluster is composed of three genes: aptA, aptB, and aptC, where deletion of either aptA (encoding a polyketide synthase) or aptB (encoding a thioesterase) yields small, mishappen hyaline ascospores; while deletion of aptC (encoding a monooxygenase) yields morphologically normal but purple ascospores. ∆aptA and ∆aptB but not ∆aptC or wild type ascospores are extremely sensitive to UV light. We find that two historical ascospore color mutants, clA6 and clB1, possess mutations in aptA and aptB sequences, respectively.


Assuntos
Aspergillus nidulans , Antraquinonas , Aspergillus nidulans/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Pigmentação , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismo , Raios Ultravioleta
18.
Fungal Genet Biol ; 152: 103567, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33989788

RESUMO

Fungi produce secondary metabolites that are not directly involved in their growth, but often contribute to their adaptation to extreme environmental stimuli and enable their survival. Conidial pigment or melanin is one of the secondary metabolites produced naturally by a polyketide synthesis (PKS) gene cluster in several filamentous fungi and is known to protect these fungi from extreme radiation conditions. Several pigmented or melanized fungi have been shown to grow under extreme radiation conditions at the Chernobyl nuclear accident site. Some of these fungi, including Paecilomyces variotii, were observed to grow towards the source of radiation. Therefore, in this study, we wanted to identify if the pigment produced by P. variotii, contributes to providing protection against radiation condition. We first identified the PKS gene responsible for synthesis of pigment in P. variotii and confirmed its role in providing protection against UV irradiation through CRISPR-Cas9 mediated gene deletion. This is the first report that describes the use of CRISPR methodology to create gene deletions in P. variotii. Further, we showed that the pigment produced by this fungus, was not inhibited by DHN-melanin pathway inhibitors, indicating that the fungus does not produce melanin. We then identified the pigment synthesized by the PKS gene of P. variotii, as a naptho-pyrone Ywa1, by heterologously expressing the gene in Aspergillus nidulans. The results obtained will further aid in understanding the mechanistic basis of radiation resistance.


Assuntos
Paecilomyces/genética , Paecilomyces/metabolismo , Paecilomyces/efeitos da radiação , Pigmentos Biológicos/biossíntese , Pigmentos Biológicos/genética , Pigmentos Biológicos/isolamento & purificação , Raios Ultravioleta , Aspergillus nidulans/genética , Byssochlamys , Acidente Nuclear de Chernobyl , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Melaninas/genética , Melaninas/isolamento & purificação , Redes e Vias Metabólicas , Testes de Sensibilidade Microbiana , Família Multigênica , Paecilomyces/isolamento & purificação , Pigmentação , Pigmentos Biológicos/metabolismo , Policetídeo Sintases/genética , Pironas/metabolismo , Metabolismo Secundário , Esporos Fúngicos/genética , Esporos Fúngicos/metabolismo
19.
iScience ; 24(5): 102395, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-33997680

RESUMO

Microbial research in space is being conducted for almost 50 years now. The closed system of the International Space Station (ISS) has acted as a microbial observatory for the past 10 years, conducting research on adaptation and survivability of microorganisms exposed to space conditions. This adaptation can be either beneficial or detrimental to crew members and spacecraft. Therefore, it becomes crucial to identify the impact of two primary stress conditions, namely, radiation and microgravity, on microbial life aboard the ISS. Elucidating the mechanistic basis of microbial adaptation to space conditions aids in the development of countermeasures against their potentially detrimental effects and allows us to harness their biotechnologically important properties. Several microbial processes have been studied, either in spaceflight or using devices that can simulate space conditions. However, at present, research is limited to only a few microorganisms, and extensive research on biotechnologically important microorganisms is required to make long-term space missions self-sustainable.

20.
Front Microbiol ; 12: 639396, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33790880

RESUMO

Four strains belonging to the family of Methylobacteriaceae were isolated from different locations on the International Space Station (ISS) across two consecutive flights. Of these, three were identified as Gram-negative, rod-shaped, catalase-positive, oxidase-positive, motile bacteria, designated as IF7SW-B2T, IIF1SW-B5, and IIF4SW-B5, whereas the fourth was identified as Methylorubrum rhodesianum. The sequence similarity of these three ISS strains, designated as IF7SW-B2T, IIF1SW-B5, and IIF4SW-B5, was <99.4% for 16S rRNA genes and <97.3% for gyrB gene, with the closest being Methylobacterium indicum SE2.11T. Furthermore, the multi-locus sequence analysis placed these three ISS strains in the same clade of M. indicum. The average nucleotide identity (ANI) values of these three ISS strains were <93% and digital DNA-DNA hybridization (dDDH) values were <46.4% with any described Methylobacterium species. Based on the ANI and dDDH analyses, these three ISS strains were considered as novel species belonging to the genus Methylobacterium. The three ISS strains showed 100% ANI similarity and dDDH values with each other, indicating that these three ISS strains, isolated during various flights and from different locations, belong to the same species. These three ISS strains were found to grow optimally at temperatures from 25 to 30°C, pH 6.0 to 8.0, and NaCl 0 to 1%. Phenotypically, these three ISS strains resemble M. aquaticum and M. terrae since they assimilate similar sugars as sole carbon substrate when compared to other Methylobacterium species. Fatty acid analysis showed that the major fatty acid produced by the ISS strains are C18 : 1-ω7c and C18 : 1-ω6c. The predominant quinone was ubiquinone 10, and the major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and an unidentified lipid. Therefore, based on genomic, phylogenetic, biochemical, and fatty acid analyses, strains IF7SW-B2T, IIF1SW-B5, and IIF4SW-B5, are assigned to a novel species within the genus Methylobacterium, and the name Methylobacterium ajmalii sp. nov. is proposed. The type strain is IF7SW-B2T (NRRL B-65601T and LMG 32165T).

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