RESUMEN
Bacterial trans-acyltransferase polyketide synthases (trans-AT PKSs) synthesize natural products with intricate structures and potent biological activities. They generally contain various unusual modules or trans-acting enzymes. Herein, we report the trans-AT PKS-derived biosynthetic pathway of the shuangdaolide with a rare internal 2-hydroxycyclopentenone moiety. The multidomain protein SdlR catalyzes the synthesis of 16,17-epoxide during polyketide chain elongation. The SdlR contains a ketoreductase, an acyl carrier protein, a flavoprotein monooxygenase, and a serine hydrolase domain. This online epoxidation occurs at unusual positions away from the thioester. Then, two tailoring enzymes, SdlB and SdlQ, convert a methylene to a carbonyl group and oxidize a hydroxyl group to a carbonyl group, respectively. The following spontaneous opening of 16,17-epoxide induces the formation of a new C-C bond to generate the 2-hydroxycyclopentenone moiety. The characterization of the shuangdaolide pathway extends the understanding of the trans-AT PKSs, facilitating the mining and identification of this class of natural products.
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Productos Biológicos , Policétidos , Sintasas Poliquetidas/metabolismo , Policétidos/química , Aciltransferasas/metabolismo , Compuestos EpoxiRESUMEN
Sesquiterpenoids with a cage-like multiring frame are rarely found in nature. Mining of the isopod-derived fungus Aspergillus parasiticus SDU001 by the one strain-many compounds (OSMAC) strategy unexpectedly led to the discovery of fungal drimane-type sesquiterpenoids astellolide R (1), featuring an unusual cage-like 6/6/5/6/5 pentacyclic ring system, astellolide S (2), possessing a rare nicotinic acid building block, and astellolides T-W (3-6). Their structures were comprehensively assigned by spectroscopic data analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Furthermore, compounds 3 and 5 exhibited anti-inflammatory activity by inhibiting the lipopolyssacharide-induced NO production in RAW264.7 macrophages with IC50 values of 6.1 ± 0.8 and 6.8 ± 0.8 µM, respectively. A putative biosynthetic pathway for 1 is proposed. Our results enlarge the chemical space of the drimane-type sesquiterpenoids generated from endophytic fungi.
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Isópodos , Sesquiterpenos , Animales , Sesquiterpenos/farmacología , Sesquiterpenos/química , Dicroismo Circular , Estructura MolecularRESUMEN
The cryptic secondary metabolite biosynthetic gene clusters (BGCs) far outnumber currently known secondary metabolites. Heterologous production of secondary metabolite BGCs in suitable chassis facilitates yield improvement and discovery of new-to-nature compounds. The two juxtaposed conventional model microorganisms, Escherichia coli, Saccharomyces cerevisiae, have been harnessed as microbial chassis to produce a bounty of secondary metabolites with the help of certain host engineering. In last decade, engineering non-model microbes to efficiently biosynthesize secondary metabolites has received increasing attention due to their peculiar advantages in metabolic networks and/or biosynthesis. The state-of-the-art synthetic biology tools lead the way in operating genetic manipulation in non-model microorganisms for phenotypic optimization or yields improvement of desired secondary metabolites. In this review, we firstly discuss the pros and cons of several model and non-model microbial chassis, as well as the importance of developing broader non-model microorganisms as alternative programmable heterologous hosts to satisfy the desperate needs of biosynthesis study and industrial production. Then we highlight the lately advances in the synthetic biology tools and engineering strategies for optimization of non-model microbial chassis, in particular, the successful applications for efficient heterologous production of multifarious complex secondary metabolites, e.g., polyketides, nonribosomal peptides, as well as ribosomally synthesized and post-translationally modified peptides. Lastly, emphasis is on the perspectives of chassis cells development to access the ideal cell factory in the artificial intelligence-driven genome era.
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Inteligencia Artificial , Policétidos , Escherichia coli/genética , Ingeniería Metabólica , Familia de Multigenes , Policétidos/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Biología SintéticaRESUMEN
Fungal natural products (NPs) usually possess complicated structures, exhibit satisfactory bioactivities, and are an outstanding source of drug leads, such as the cholesterol-lowering drug lovastatin and the immunosuppressive drug mycophenolic acid. The fungal NPs biosynthetic genes are always arranged within one single biosynthetic gene cluster (BGC). However, a rare but fascinating phenomenon that a crosstalk between two separate BGCs is indispensable to some fungal dimeric NPs biosynthesis has attracted increasing attention. The hybridization of two separate BGCs not only increases the structural complexity and chemical diversity of fungal NPs, but also expands the scope of bioactivities. More importantly, the underlying mechanism for this hybridization process is poorly understood and needs further exploration, especially the determination of BGCs for each building block construction and the identification of enzyme(s) catalyzing the two biosynthetic precursors coupling processes such as Diels-Alder cycloaddition and Michael addition. In this review, we summarized the fungal NPs produced by functional crosstalk of two discrete BGCs, and highlighted their biosynthetic processes, which might shed new light on genome mining for fungal NPs with unprecedented frameworks, and provide valuable insights into the investigation of mysterious biosynthetic mechanisms of fungal dimeric NPs which are constructed by collaboration of two separate BGCs.
RESUMEN
Angucyclines and angucyclinones are aromatic polyketides with intriguing structures and therapeutic value. Genome mining of the rare marine actinomycete Saccharothrix sp. D09 led to the identification of a type II polyketide synthase biosynthetic gene cluster, sxn, which encodes several distinct subclasses of oxidoreductases, implying that this strain has the potential to produce novel polycyclic aromatic polyketides with unusual redox modifications. The "one strain-many compounds" (OSMAC) strategy and comparative metabolite analysis facilitated the discovery of 20 angucycline derivatives from the D09 strain, including six new highly oxygenated saccharothrixins D-I (1-6), four new glycosylated saccharothrixins J-M (7-10), and 10 known analogues (11-20). Their structures were elucidated based on detailed HRESIMS, NMR spectroscopic, and X-ray crystallographic analysis. With the help of gene disruption and heterologous expression, we proposed their plausible biosynthetic pathways. In addition, compounds 3, 4, and 8 showed antibacterial activity against Helicobacter pylori with MIC values ranging from 16 to 32 µg/mL. Compound 3 also revealed anti-inflammatory activity by inhibiting the production of NO with an IC50 value of 28 µM.
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Actinobacteria/metabolismo , Sintasas Poliquetidas/genética , Policétidos/aislamiento & purificación , Actinobacteria/genética , Antibacterianos/farmacología , Antiinflamatorios/farmacología , Vías Biosintéticas , Descubrimiento de Drogas , Genoma Bacteriano , Familia de Multigenes , Policétidos/química , Policétidos/farmacología , Microbiología del AguaRESUMEN
A cryptic trans-acyltransferase polyketide synthase biosynthetic gene cluster sdl (80 kb) from Streptomyces sp. B59 was cloned and transferred into a heterologous host Streptomyces albus J1074, resulting in a class of polycyclic macrolide shuangdaolides A-D (1-4) and dumulmycin (5). Heterologous expression and gene inactivation experiments allowed the identification of two biosynthetic intermediates, 6 and 7, suggesting an unusual multidomain SDR oxidoreductase SdlR in charge of the formation of a rare 2-hydroxycyclopentenone moiety in this class of compounds.
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Antibacterianos/biosíntesis , Macrólidos/química , Sintasas Poliquetidas/química , Inhibidores de la Síntesis de la Proteína/química , Streptomyces/química , Antibacterianos/química , Macrólidos/metabolismo , Estructura Molecular , Familia de Multigenes , Sintasas Poliquetidas/metabolismo , Inhibidores de la Síntesis de la Proteína/metabolismoRESUMEN
Siderophores are secreted by microorganisms to survive in iron-depleted conditions, and they also possess tremendous therapeutic potential. Genomic-inspired isolation facilitated the identification of eight amphiphilic siderophores, saccharochelins A-H (1-8), from a rare marine-derived Saccharothrix species. Saccharochelins feature a series of fatty acyl groups appended to the same tetrapeptide skeleton. With the help of gene disruption and heterologous expression, we identified the saccharochelin biosynthetic pathway. The diversity of saccharochelins originates from the flexible specificity of the starter condensation (CS) domain at the beginning of the nonribosomal peptide synthetase (NRPS) toward various fatty acyl substrates. Saccharochelins showed cytotoxicity against several human tumor cell lines, with IC50 values ranging from 2.3 to 17 µM. Additionally, the fatty acid side chains of the saccharochelins remarkably affected the cytotoxicity, suggesting changing the N-terminal acyl groups of lipopeptides may be a promising approach to produce more potent derivatives.
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Actinobacteria/química , Sideróforos/química , Actinobacteria/genética , Antineoplásicos/química , Antineoplásicos/farmacología , Organismos Acuáticos/química , Bahías/microbiología , Vías Biosintéticas , Línea Celular Tumoral , China , Ácidos Grasos , Sedimentos Geológicos/microbiología , Humanos , Estructura Molecular , Familia de Multigenes , Agua de Mar/microbiología , Sideróforos/farmacologíaRESUMEN
BACKGROUND: This study is carried out targeting the problem of slow response time and performance degradation of imaging system caused by large data of medical ultrasonic imaging. In view of the advantages of CS, it is applied to medical ultrasonic imaging to solve the above problems. OBJECTIVES: Under the condition of satisfying the speed of ultrasound imaging, the quality of imaging can be further improved to provide the basis for accurate medical diagnosis. METHODS: According to CS theory and the characteristics of the array ultrasonic imaging system, block compressed sensing ultrasonic imaging algorithm is proposed based on wavelet sparse representation. RESULTS: Three kinds of observation matrices have been designed on the basis of the proposed algorithm, which can be selected to reduce the number of the linear array channels and the complexity of the ultrasonic imaging system to some extent. CONCLUSION: The corresponding simulation program is designed, and the result shows that this algorithm can greatly reduce the total data amount required by imaging and the number of data channels required for linear array transducer to receive data. The imaging effect has been greatly improved compared with that of the spatial frequency domain sparse algorithm.
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Compresión de Datos , Procesamiento de Imagen Asistido por Computador/métodos , Ultrasonografía/métodos , Análisis de Ondículas , Algoritmos , Simulación por Computador , Humanos , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: Improving patients' perception of social support is significant not only for their re-adaptation to life but also for alleviating caregivers' burden. AIM: This study aims to examine an integrated model regarding social support, psychotic symptoms and caregiver burden. METHODS: Persons with schizophrenia (N1 = 300) and their family caregivers (N2 = 300) in Xinjin County, Chengdu, China, completed the survey to report their demographics, patients' perception of social support (Duke Social Support Index), psychotic symptoms (Positive and Negative Syndrome Scale) and caregiver burden (Burden Scale for Family Caregivers, Short Version). Structural equation modelling was utilised to test the proposed model. RESULTS: The degree of caregiver burden differed significantly within subgroups of patients' gender and education, as well as caregivers' gender, education and employment. Caregiver burden was negatively related to patients' age and household income. Social interaction partially mediated the relationship between instrumental and subjective social support (total effect = 0.451, p < .01). Subjective social support fully mediated the impact of social interaction on psychotic symptoms (total effect = -0.099, p < .05). In the final model, instrumental social support was positively associated with social interaction (p < .001) and increased subjective social support (p < .05). Increased subjective social support showed correlation with a lower degree of psychotic symptoms (p < .01), which was related to a lower level of caregiver burden (p < .001). CONCLUSION: This study shows the associations of patients' social support with psychotic symptoms and caregiver burden. Culture-specific psychosocial interventions should be provided for both patients and caregivers to enrich external support and reduce psychotic symptoms and caregivers' burden within the health care environment.
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Cuidadores/psicología , Esquizofrenia/terapia , Apoyo Social , Adulto , Anciano , Cuidadores/economía , China , Costo de Enfermedad , Femenino , Humanos , Relaciones Interpersonales , Masculino , Persona de Mediana Edad , Calidad de Vida , Análisis de Regresión , Esquizofrenia/economía , Encuestas y CuestionariosRESUMEN
Oxidative damage to the constituents of the eye lens is a major mechanism in the initiation and development of cataract. Lunasin, a 43-amino acids chemoprevention peptide, has been proved to possess potent anti-oxidative activity other than its established anticancer activities. Herein, we explored whether lunasin has preventative effects on d-galactose-induced experimental cataract in rat. After modeling, SD rats were administrated by instillation, 80 µM of lunasin eye drops to each eye thrice daily and consecutively for 30 days. As a result, lunasin treatment effectively inhibited the progression of d-galactose-induced experimental cataract, and protected the lenses of rats from oxidative damage and attenuated the lipid peroxidation through up-regulation of antioxidant enzymes, and inhibited the activation of polyol pathway by decreasing AR activity. Additionally, in vitro studies proved that lunasin treatment could protect human lens epithelial cells (hLECs) against d-galactose induced cell damage and apoptosis, and up-regulate antioxidant enzymes. This is the first demonstration that lunasin could inhibit d-galactose-induced experimental cataract in rats by protecting against oxidative damage and inhibiting the activation of polyol pathway.
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Catarata/inducido químicamente , Catarata/prevención & control , Galactosa , Cristalino/efectos de los fármacos , Sustancias Protectoras/uso terapéutico , Proteínas de Soja/uso terapéutico , Animales , Apoptosis/efectos de los fármacos , Catarata/metabolismo , Catarata/patología , Línea Celular , Femenino , Humanos , Cristalino/metabolismo , Cristalino/patología , Peroxidación de Lípido/efectos de los fármacos , Masculino , Estrés Oxidativo/efectos de los fármacos , Ratas Sprague-Dawley , Proteínas de Soja/químicaRESUMEN
To develop an efficient and cost-effective approach for the production of small preventive peptide lunasin with correct natural N terminus, a synthetic gene was designed by OPTIMIZER & Gene Designer and cloned into pTWIN1 vector at SapI and PstI sites. Thus, lunasin was N-terminally fused to the pH-induced self-cleavable Ssp DnaB mini-intein linked to a chitin binding domain (CBD) with no extra residues. The resultant fusion protein was highly expressed by lactose induction in Escherichia coli BL21 (DE3) in a 7-l bioreactor and bound to a chitin affinity column. After washing the impurities, the Ssp DnaB intein mediated on-column self-cleavage was easily triggered by shifting pH and temperature to allow the native lunasin released. The final purified lunasin yielded up to 75 mg/l medium. Tricine/SDS-PAGE and matrix-assisted laser desorption time-of-flight (MALDI-TOF)/mass spectrometry (MS) verified the structural authenticity of the product, implying the correct cleavage at the junction between Ssp DnaB intein and lunasin. MTT assay confirmed its potent proliferation inhibitory activity to human cancer cells HCT-116 and MDA-MB-231; however, no cytotoxicity to normal human lens epithelial cell SRA01/04 and hepatoma HepG2. Taken together, we provide a novel strategy to produce recombinant native lunasin with correct N-terminal processing by using the pH-induced self-cleavable Ssp DnaB mini-intein.
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AdnB Helicasas/genética , Escherichia coli/genética , Inteínas , Proteínas de Soja/biosíntesis , Secuencia de Bases , Cartilla de ADN , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Reacción en Cadena de la Polimerasa , Proteínas de Soja/química , Proteínas de Soja/genética , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
BACKGROUND: There are no direct comparisons of paliperidone extended-release (ER), aripiprazole and ziprasidone in efficacy and metabolic influence in patients with first-episode schizophrenia. OBJECTIVE: The present study examined the efficacy and metabolic influence of paliperidone ER, aripiprazole and ziprasidone in patients with first-episode schizophrenia in China. METHODS: Subjects were recruited from outpatient and 254 patients entered the trial. These patients received treatment randomly with paliperidone ER, aripiprazole and ziprasidone and were assessed at baseline, 13, 26 and 52 weeks, respectively with Positive and Negative Syndrome Scale (PANSS), 7-item Clinical Global Impressions-Severity (CGI-S), anthropometric (weight, body mass index and waist circumference) and metabolic (fasting blood glucose, HbA1c, cholesterol, high density lipoproteins (HDL), low density lipoproteins and triglycerides) measures. RESULTS: A total of 203 patients completed the trial. Paliperidone group had significant greater reduction in PANSS than aripiprazole group and ziprasidone group from 13 weeks, although the a reduction in PANSS of each group was more than 20%. There was no difference in CGI-S among the three groups, and all three groups had a significant reduction from baseline in CGI-S. Aripiprazole group increased in weight and body mass index despite no statistical change in waist circumference. Other two groups showed no changes in anthropometric measure. At the end of the study, two glucose metabolic indices (fasting blood glucose and HbA1c) of aripiprazole group were significantly higher than that of baseline. In lipid metabolism, aripiprazole group reduced triglycerides significantly and had no changes in other indices. Paliperidone group reduced HDL and increased triglycerides despite no changes in glucose metabolism. Ziprasidone group also had no significant changes in glucose metabolism, but reduced cholesterol, low density lipoproteins and increased HDL. Furthermore, 22 subjects in three groups reached the diagnostic criteria of metabolic syndrome. CONCLUSIONS: Paliperidone ER, aripiprazole and ziprasidone are effective in treating first-episode schizophrenia, and the ranking of efficacy from high to low is paliperidone ER > aripiprazole > ziprasidone. Paliperidone ER can impair lipid metabolism potentially but had no influence on glucose metabolism. Aripiprazole can damage glucose metabolism and has little influence on lipid metabolism. Ziprasidone is considered an atypical antipsychotic with no evidence of harm to glucose and lipid metabolism.
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Antipsicóticos/uso terapéutico , Isoxazoles/uso terapéutico , Enfermedades Metabólicas/inducido químicamente , Piperazinas/uso terapéutico , Pirimidinas/uso terapéutico , Quinolonas/uso terapéutico , Esquizofrenia/tratamiento farmacológico , Tiazoles/uso terapéutico , Adulto , Antipsicóticos/efectos adversos , Aripiprazol , Índice de Masa Corporal , China , Preparaciones de Acción Retardada/uso terapéutico , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Femenino , Estudios de Seguimiento , Humanos , Hiperglucemia/inducido químicamente , Hiperlipidemias/inducido químicamente , Isoxazoles/efectos adversos , Masculino , Palmitato de Paliperidona , Piperazinas/efectos adversos , Escalas de Valoración Psiquiátrica , Pirimidinas/efectos adversos , Quinolonas/efectos adversos , Esquizofrenia/sangre , Tiazoles/efectos adversos , Aumento de Peso/efectos de los fármacos , Adulto JovenRESUMEN
BACKGROUND: China has recently introduced a community-based service network for managing individuals with schizophrenia but there has been relatively little formal evaluation of the effectiveness of this approach. OBJECTIVE: Assess the retention rate and the two-year re-hospitalization rate of patients who are enrolled in the community management network in Chengdu, China. METHODS: Patients with a confirmed diagnosis of schizophrenia who had at least one prior hospitalization and who were enrolled in the service network at the community health clinics in 14 communities in the Jinniu District of Chengdu and 10 communities in the Qingyang District of Chengdu participated in the two-year prospective follow-up assessment. Detailed demographic and clinical information was obtained at the time of intake into the follow-up program and their hospitalization status was recorded during monthly evaluations over the subsequent two years. RESULTS: Of the 1 027 participating patients, 963 (93.8%) remained in the program for the entire two-year period. Patients with a lower level of education and those who did not live with family members were more likely to drop-out of the network. Among the 963 patients who completed the follow-up 174 (18.1%) were re-hospitalized over the two-year period. Multivariate logistic regression identified factors related to re-hospitalization: not married or not living with family members, having more prominent positive and negative symptoms at the time of intake, and using medication less in the six months prior to intake. CONCLUSION: The 94% two-year retention of patients in this urban community management network for individuals with schizophrenia was excellent and the two-year re-hospitalization rate of 18% is better than that reported in most similar programs in other countries. Patients not living with family members were at higher risk for dropping out of the network and for re-hospitalization so this is a high-risk group that deserves special attention. Standardization of the community interventions and longer follow-up studies with control communities that consider the full range of factors relevant to the well-being of patients with schizophrenia (i.e., social integration, quality of life and re-hospitalization) are needed to definitively demonstrate the effectiveness of this community service network.