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Marine symbiotic and epiphyte microorganisms are sources of bioactive or structurally novel natural products. Metabolic blockade-based genome mining has been proven to be an effective strategy to accelerate the discovery of natural products from both terrestrial and marine microorganisms. Here, the metabolic blockade-based genome mining strategy was applied to the discovery of other metabolites in a sea anemone-associated Streptomyces sp. S1502. We constructed a mutant Streptomyces sp. S1502/Δstp1 that switched to producing the atypical angucyclines WS-5995 A-E, among which WS-5995 E is a new compound. A biosynthetic gene cluster (wsm) of the angucyclines was identified through gene knock-out and heterologous expression studies. The biosynthetic pathways of WS-5995 A-E were proposed, the roles of some tailoring and regulatory genes were investigated, and the biological activities of WS-5995 A-E were evaluated. WS-5995 A has significant anti-Eimeria tenell activity with an IC50 value of 2.21 µM. The production of antibacterial streptopyrroles and anticoccidial WS-5995 A-E may play a protective role in the mutual relationship between Streptomyces sp. S1502 and its host.
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Família Multigênica , Anêmonas-do-Mar , Streptomyces , Streptomyces/genética , Streptomyces/metabolismo , Animais , Antibacterianos/farmacologia , Vias Biossintéticas/genética , Genoma Bacteriano , Produtos Biológicos/farmacologia , Antraquinonas/farmacologia , Anguciclinas e AnguciclinonasRESUMO
The flower of Syringa pubescens Turcz. is used in Chinese folk medicine and also as a flower tea for healthcare. The effects of five drying methods on the active compound contents, the antioxidant abilities, anti-inflammatory properties and enzyme inhibitory activities were evaluated. The plant materials were treated using shade-drying, microwave-drying, sun-drying, infrared-drying and oven-drying. The seven active compounds were simultaneously determined using an HPLC method. Furthermore, the chemical profile was assessed using scanning electron microscopy, ultraviolet spectroscopy and infrared spectroscopy. The antioxidant capacities and protective effects on L02 cells induced with hydrogen peroxide were measured. The anti-inflammatory effects on lipopolysaccharide-induced RAW264.7 cells were investigated. The enzyme inhibitory activities were determined against α-amylase, α-glucosidase cholinesterases and tyrosinase. The results indicated that drying methods had significant influences on the active compound contents and biological properties. Compared with other samples, the OD samples possessed low IC50 values with 0.118 ± 0.004 mg/mL for DPPH radical, 1.538 ± 0.0972 for hydroxyl radical and 0.886 ± 0.199 mg/mL for superoxide radical, while the SHD samples had stronger reducing power compared with other samples. The SHD samples could be effective against H2O2-induced injury on L02 cells by the promoting of T-AOC, GSH-PX, SOD and CAT activities and the reducing of MDA content compared with other samples. Furthermore, SPF samples, especially the SHD sample, could evidently ameliorate inflammation through the inhibition of IL-6, IL-1ß and TNF-α expression. All the studied SPF samples exhibited evidently inhibitory effects on the four enzymes. The IC50 values of inhibitory activity on α-glucosidase and α-amylase from SHD sample were 2.516 ± 0.024 and 0.734 ± 0.034 mg/mL, respectively. SD samples had potential inhibitory effects on cholinesterases and tyrosinase with IC50 values of 3.443 ± 0.060 and 1.732 ± 0.058 mg/mL. In consideration of active compound contents and biological activities, it was recommended that SHD and SD be applied for drying SPF at an industrial scale.
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Antioxidantes , Syringa , Antioxidantes/farmacologia , Antioxidantes/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Monofenol Mono-Oxigenase , alfa-Glucosidases , Peróxido de Hidrogênio , Anti-Inflamatórios/farmacologia , Flores , alfa-Amilases , ColinesterasesRESUMO
BACKGROUND: Ovarian neuroendocrine carcinoma (O-NEC) is a relatively uncommon neoplasm, and the current knowledge regarding its diagnosis and management is limited. In this series, our objective was to provide an overview of the clinicopathological characteristics of the disease by analyzing clinical case data to establish a theoretical foundation for the diagnosis and management of O-NEC. CASE PRESENTATION: We included three patients in the present case series, all of whom were diagnosed with primary O-NEC based on pathomorphological observation and immunohistochemistry. Patient 1 was a 62-year-old patient diagnosed with small cell carcinoma (SCC) of the pulmonary type. Post-surgery, the patient was diagnosed with stage II SCC of the ovary and underwent standardized chemotherapy; however, imaging examinations conducted at the 16-month follow-up revealed the existence of lymph node metastasis. Unfortunately, she passed away 21 months after the surgery. The other two patients were diagnosed with carcinoid tumors, one at age 39 and the other at age 71. Post-surgery, patient 2 was diagnosed with a carcinoid in the left ovary, whereas patient 3 was diagnosed with a carcinoid in her right ovary based on clinical evaluation. Neither of the cases received adjuvant therapy following surgery; however, they have both survived for 9 and 10 years, respectively, as of date. CONCLUSION: Primary O-NECs are rare and of diverse histological types, each of which has its own unique biological features and prognosis. SCC is a neoplasm characterized by high malignancy and a poor prognosis, whereas carcinoid tumors are of lesser malignancy and have a more favorable prognosis.
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Tumor Carcinoide , Carcinoma Neuroendócrino , Carcinoma de Células Pequenas , Tumores Neuroendócrinos , Neoplasias Ovarianas , Feminino , Humanos , Adulto , Idoso , Pessoa de Meia-Idade , Carcinoma Neuroendócrino/diagnóstico , Carcinoma Neuroendócrino/terapia , Carcinoma Neuroendócrino/patologia , Tumores Neuroendócrinos/diagnóstico , Tumores Neuroendócrinos/patologia , Prognóstico , Carcinoma de Células Pequenas/diagnóstico , Carcinoma de Células Pequenas/terapia , Carcinoma de Células Pequenas/patologia , Tumor Carcinoide/diagnóstico , Tumor Carcinoide/patologia , Carcinoma Epitelial do Ovário , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/terapiaRESUMO
With the invasion of green tides and the increase of urban green areas worldwide, multimillion tons of Enteromorpha need to be reutilized. In this study, Enteromorpha prolifera powder is considered a promising biomass resource for the production of commercial chemical products production. Ilamycins, novel cyclic heptapeptides with significant anti-TB activities, are isolated from Streptomyces atratus SCSIO ZH16, a deep-sea-derived strain. Using EP powder as a nitrogen source, the production of ilamycins reached 709.97 mg/L through optimization of the nitrogen source using the engineered strain S. atratus SCSIO ZH16 ΔR. After mutant strain constructions and tests, strain S. atratus SCSIO ZH16 ΔR::bldD EP powder achieved a higher production titer of ilamycins. Furthermore, the production titer of ilamycins and ilamycin E reached 1561.77 mg/L and 745.44 mg/L, respectively, in a 5 L bioreactor. This study suggests that E. prolifera is a promising and eco-friendly nitrogen source for the production of ilamycins.
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Background: Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is the standard treatment for patients with peritoneal cancer (PC). Following CRS-HIPEC, patients may also face risks caused by whole body hyperthermia. This study analyzed the incidence of temperature increases following CRS-HIPEC and identified the attendant risk factors. Methods: A retrospective analysis was carried out among 458 patients who received CRS-HIPEC at the Fourth Hospital of Hebei Medical University between August 2018 and January 2021. The patients were divided into two groups according to post-HIPEC axillary temperature (≥38°C), with the demographics and the laboratory test results subsequently analyzed and compared, and the risk factors pertaining to temperature increases analyzed using univariate and multivariate logistic regression. Results: During CRS-HIPEC, 32.5% (149/458) of the patients with a temperature increase had an axillary temperature of not lower than 38°C, and 8.5% (39/458) of the patients with hyperpyrexia had an axillary temperature of not lower than 39°C. Female gender, gynecological malignancies, type of chemotherapy drug, increased postoperative neutrophil percentage, and a sharp drop in postoperative prealbumin were associated with the incidence of a temperature increase and axillary temperatures of >38°C. Among these factors, the type of chemotherapy drug was identified as an independent risk factor for a temperature increase during CRS-HIPEC. Conclusion: By determining the risk factors pertaining to temperature increases during CRS-HIPEC, medical staff can identify the attendant risks among the patients and thus take preventive measures in a timely manner to maintain the patient's body temperature at a stable level. This suggests that further clinical research should be conducted to build a risk-prediction model for temperature increases following CRS-HIPEC.
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Marine-derived fungi are emerging as prolific workhorses of structurally novel natural products (NPs) with diverse bioactivities. However, the limitation of available selection markers hampers the exploration of cryptic NPs. Recyclable markers are therefore valuable assets in genetic engineering programs for awaking silent SM clusters. Here, both pyrG and amdS-based recyclable marker cassettes were established and successfully applied in marine-derived fungi Aspergillus sp. SCSIO SX7S7 and Spiromastix sp. SCSIO F190, respectively. Using pyrG recyclable marker, a markerless 7S7-∆depH strain with a simplified HPLC background was built by inactivating a polyketide synthase (PKS) gene depH and looping out the pyrG recyclable marker after depH deletion. Meanwhile, an amdS recyclable marker system was also developed to help strains that are difficult to use pyrG marker. By employing the amdS marker, a backbone gene spm11 responsible for one major product of Spiromastix sp. SCSIO F190 was inactivated, and the amdS marker was excised after using, generating a relatively clean F190-∆spm11 strain for further activation of novel NPs. The collection of two different recycle markers will guarantee flexible application in marine-derived fungi with different genetic backgrounds, enabling the exploitation of novel structures in various fungi species with different genome mining strategies.
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Asparagus belongs to the Liliaceae family and has important economic and pharmacological value. Lignin plays a crucial role in cell wall structural integrity, stem strength, water transport, mechanical support and plant resistance to pathogens. In this study, various biological methods were used to study the mechanism of shading on the asparagus lignin accumulation pathway. The physiological results showed that shading significantly reduced stem diameter and cell wall lignin content. Microstructure observation showed that shading reduced the number of vascular bundles and xylem area, resulting in decreased lignin content, and thus reducing the lignification of asparagus. Cinnamic acid, caffeic acid, ferulic acid and sinapyl alcohol are crucial intermediate metabolites in the process of lignin synthesis. Metabolomic profiling showed that shading significantly reduced the contents of cinnamic acid, caffeic acid, ferulic acid and sinapyl alcohol. Transcriptome profiling identified 37 differentially expressed genes related to lignin, including PAL, C4H, 4CL, CAD, CCR, POD, CCoAOMT, and F5H related enzyme activity regulation genes. The expression levels of POD, CCoAOMT, and CCR genes were significantly decreased under shading treatment, while the expression levels of CAD and F5H genes exhibited no significant difference with increased shading. The downregulation of POD, CCoAOMT genes and the decrease in CCR gene expression levels inhibited the activities of the corresponding enzymes under shading treatment, resulting in decreased downstream content of caffeic acid, ferulic acid, sinaperol, chlorogenic acid and coniferin. A significant decrease in upstream cinnamic acid content was observed with shading, which also led to decreased downstream metabolites and reduced asparagus lignin content. In this study, transcriptomic and metabolomic analysis revealed the key regulatory genes and metabolites of asparagus lignin under shading treatment. This study provides a reference for further understanding the mechanism of lignin biosynthesis and the interaction of related genes.
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Adaptação Fisiológica , Asparagus , Lignina , Luz Solar , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Lignina/biossíntese , Lignina/genética , Lignina/metabolismo , Transcriptoma , Asparagus/genética , Asparagus/metabolismo , Adaptação Fisiológica/genética , Adaptação Fisiológica/fisiologiaRESUMO
Three diphenyl ethers (1-3) and a cyclopentenone (4), together with seven known compounds (5-11), were isolated from the fermentation broth of the marine sediment-derived fungus Spiromastix sp. SCSIO F190. Compounds 3 and 4 were found to exist as a pair of atropisomers (3a, 3b) and racemates (4a, 4b), respectively. The planar structures of compounds 1-4 were elucidated on the basis of NMR and HRESIMS data sets. The absolute configurations of 2 and 3 were determined by spectroscopic and single-crystal X-ray diffraction analyses, whereas the configuration of 4 was determined by spectroscopic and chiral analyses. All compounds, except for 4 and 11, displayed activities against various pathogenic bacteria. Notably, compounds 1-4, especially 1, exhibited strong activity against Gram-positive bacteria, including methicillin-resistant bacterial strains of Staphylococcus aureus (MRSA), Enterococcus faecalis ATCC 29212, and Bacillus subtilis BS01, with MIC values ranging from 0.5 to 4 µg/mL. Moreover, the structure-activity relationship analyses of the active compounds and their analogues revealed the critical structural features correlating to the observed antimicrobial activities, herein providing insights for antimicrobial drug development.
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Anti-Infecciosos , Staphylococcus aureus Resistente à Meticilina , Policetídeos , Antibacterianos/química , Policetídeos/química , Estrutura Molecular , Fungos , Espectroscopia de Ressonância Magnética , Bactérias , Testes de Sensibilidade MicrobianaRESUMO
The one strain many compounds (OSMAC) strategy is an effective method for activating silent gene clusters by cultivating microorganisms under various conditions. The whole genome sequence of the marine-derived strain Streptomyces globisporus SCSIO LCY30 revealed that it contains 30 biosynthetic gene clusters (BGCs). By using the OSMAC strategy, three types of secondary metabolites were activated and identified, including three angucyclines, mayamycin A (1), mayamycin B (2), and rabolemycin (3); two streptophenazines (streptophenazin O (4) and M (5)); and a macrolide dimeric dinactin (6), respectively. The biosynthetic pathways of the secondary metabolites in these three families were proposed based on the gene function prediction and structural information. The bioactivity assays showed that angucycline compounds 1-3 exhibited potent antitumor activities against 11 human cancer cell lines and antibacterial activities against a series of Gram-positive bacteria. Mayamycin (1) selectively exhibited potent cytotoxicity activity against triple-negative breast cancer (TNBC) cell lines such as MDA-MB-231, MDA-MB-468, and Bt-549, with IC50 values of 0.60-2.22 µM.
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Família Multigênica , Streptomyces , Humanos , Benzo(a)Antracenos , Streptomyces/genética , Antibacterianos/farmacologiaRESUMO
The actinopyrone biosynthetic gene cluster (atpn) lacks glycosyl- and methyltransferase genes, yet its product clearly calls for such enzymes. Using bioinformatics and biochemical methods, we confirmed that the mt3913 and gt723 genes, well beyond the atpn cluster boundaries, encode methyltransferase and glycosyltransferase, respectively. Moreover, homologous protein GT1507 enabled us to produce 14 non-natural actinopyrone analogues. PM050463 (3) was found to display potent anti-Helicobacter pylori activity and no signs of cytotoxicity.
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Helicobacter pylori , Metiltransferases , Metiltransferases/metabolismo , Glicosiltransferases/genética , Família Multigênica , Helicobacter pylori/genéticaRESUMO
A cage-covalent organic framework (COF)-TP {T = bis(tetraoxacalix[2]arene[2]triazine); P = piperazine}, a novel two-dimensional covalent organic skeleton substituted with a nucleophilic cyanuric chloride analogue, was synthesized by a simple polymerization process. Cage-COF-TP is advantageous owing to its good structural order, permanent porosity, and low preparation cost. This skeleton was employed as a cost-effective adsorbent for the intermittent adsorption of an organic dye from aqueous solutions. Adsorption experiments were carried out at different initial dye concentrations, contact times, and solution pH. The adsorption kinetics followed the pseudo-second order model, and the results of thermodynamic studies were consistent with the Langmuir isotherm model. The high degree of matching between the size and shape of malachite green (MG) and the shrunken channels present in Cage-COF-TP were responsible for the enhanced adsorption ability of this material. Furthermore, theoretical calculations indicated that the high adsorption of the studied adsorbent can be attributed to the presence of nitrogen-rich triazine units in the Cage-COF-TP, which are expected to strengthen its affinity to guest molecules. The obtained results showed that the developed adsorbent is an efficient adsorbent that is theoretically capable of stimulating the removal of â¼2000 mg/g MG from wastewater at ambient temperature. This study will therefore be expected to promote the development of new functional materials based on COFs.
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Wasabi (Eutrema japonicum), also known as Japanese horseradish, is a perennial herb widely used in Japanese cuisine for its special flavour. The health-promoting phytochemicals and antioxidant capacity of four organs (leaf, petiole, rhizome, and root) of two cultivars (Chuankui-1 and Chuankui-2) of wasabi from two producing areas, Leibo and Guangyuan in Sichuan Province, China, were investigated in this study. The results showed that leaves were rich in pigments, soluble protein, ascorbic acid, and total phenolics and had the highest antioxidant capacity. Soluble sugars were highest in the petioles and were 1.1- to 5-fold higher than those in the other three organs. Glucosinolates and glucosinolate breakdown products (GBPs) were the most abundant in rhizomes, and their maximum values were 271.61 mmol kg-1 DW and 249.78 mmol kg-1 DW, respectively. The rhizomes of Chuankui-1 in Leibo and the leaves of Chuankui-1 in Guangyuan were superior in terms of glucosinolates and GBPs. These findings provide new insights that will aid the use of wasabi cultivars; they also have implications for the environmental characteristics needed to obtain better quality wasabi products. In the future, metabolome and transcriptome can be used to analyze the potential mechanism of differences among typical varieties, origins and parts.
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Marine microorganisms produce a variety of bioactive secondary metabolites, which represent a significant source of novel antibiotics. Heterologous expression is a valuable tool for discovering marine microbial secondary metabolites; however, marine-derived chassis cell is very scarce. Here, we build an efficient plug-and-play marine-derived gene clusters expression platform 1.0 (MGCEP 1.0) by the systematic engineering of the deep-sea-derived Streptomyces atratus SCSIO ZH16. For a proof of concept, four families of microbial bioactive metabolite biosynthetic gene clusters (BGCs), including alkaloids, aminonucleosides, nonribosomal peptides, and polyketides, were efficiently expressed in this platform. Moreover, 19 compounds, including two new angucycline antibiotics, were produced in MGCEP 1.0. Dynamic patterns of global biosynthetic gene expression in MGCEP 1.0 with or without a heterologous gene cluster were revealed at the transcriptome level. The platform MGCEP 1.0 provides new possibilities for expressing microbial secondary metabolites, especially of marine origin.
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Família Multigênica , Policetídeos , Policetídeos/metabolismo , Engenharia Genética , Antibacterianos/químicaRESUMO
Continuously mining the Streptomyces olivaceus SCSIO T05 genome leads to the identification of new lipopeptides (autucedines A-C), constituting members of the 10th skeleton isolated from this strain. The corresponding biosynthetic gene cluster (aut) was verified by heterogeneous expression, and another two analogues (autucedines D and E) were isolated from the heterogeneous expression strain. Gene inactivation experiments revealed that construction of the unique "lipochain-linked dihydro-ß-alanine" unit takes place prior to the NRPS assembly line.
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Família Multigênica , Peptídeo Sintases , Lipopeptídeos , Peptídeo Sintases/genética , Peptídeo Sintases/metabolismo , beta-Alanina/genéticaRESUMO
Marine-derived fungi are emerging as attractive producers of structurally novel secondary metabolites with diverse bioactivities. However, the lack of efficient genetic tools limits the discovery of novel compounds and the elucidation of biosynthesis mechanisms. Here, we firstly established an effective PEG-mediated chemical transformation system for protoplasts in two marine-derived fungi, Spiromastix sp. SCSIO F190 and Aspergillus sp. SCSIO SX7S7. Next, we developed a simple and versatile CRISPR-Cas9-based gene disruption strategy by transforming a target fungus with a single plasmid. We found that the transformation with a circular plasmid encoding cas9, a single-guide RNA (sgRNA), and a selectable marker resulted in a high frequency of targeted and insertional gene mutations in both marine-derived fungal strains. In addition, the histone deacetylase gene rpd3 was mutated using the established CRISPR-Cas9 system, thereby activating novel secondary metabolites that were not produced in the wild-type strain. Taken together, a versatile CRISPR-Cas9-based gene disruption method was established, which will promote the discovery of novel natural products and further biological studies.
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Streptomyces sp. SCSIO ZS0520 is a deep-sea hydrothermal vent-derived actinomycete. Our previous metabolism investigation showed that Streptomyces sp. SCSIO ZS0520 is a producer of cytotoxic actinopyrones. Here, another four types of secondary metabolites were identified, including six salinomycin isomers (2-7), the macrolide elaiophylin (8), the triterpene N-acetyl-aminobacteriohopanetriol (9), and the pyrone minipyrone (10). Among them, compounds 2-6 and 10 are new compounds. To understand the biosynthetic pathway of these compounds, a bioinformatic analysis of the whole genome was carried out, which identified 34 secondary metabolite biosynthetic gene clusters. Next, the biosynthetic pathways responsive to four types of products were deduced on the basis of gene function predictions and structure information. Taken together, these findings prove the metabolite potential of ZS0520 and lay the foundations to solve the remaining biosynthetic issues in four types of marine natural products.
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Fontes Hidrotermais , Família Multigênica , Metabolismo Secundário , Streptomyces , Vias Biossintéticas , Fontes Hidrotermais/microbiologia , Streptomyces/química , Streptomyces/genéticaRESUMO
BACKGROUND: Tuberculosis (TB) and its evolving drug resistance have exerted severe threats on the global health, hence it is still essential to develop novel anti-TB antibiotics. Ilamycin-E1/E2 is a pair of cycloheptapeptide enantiomers obtained from a marine Streptomyces atratus SCSIO ZH16-ΔilaR mutant, and has presented significant anti-TB activities as promising drug lead compounds, but their clinical development has been hampered by low fermentation titers. MAIN METHODS AND MAJOR RESULTS: By applying the statistical Plackett-Burman design (PBD) model, bacterial peptone was first screened out as the only significant but negative factor to affect the ilamycin-E1/E2 production. Subsequent single factor optimization in shaking flasks revealed that the replacement of bacterial peptone with malt extract could not only eliminate the accumulation of porphyrin-type competitive byproducts but also improve the titer of ilamycin-E1/E2 from original 13.6 ± 0.8 to 142.7 ± 5.7 mg L-1 , about 10.5-fold increase. Next, a pH coordinated feeding strategy was adopted in 30 L fermentor and obtained 169.8 ± 2.5 mg L-1 ilamycin-E1/E2, but further scaled-up production in 300 L fermentor only gave a titer of 131.5 ± 7.5 mg L-1 due to the unsynchronization of feeding response and pH change. Consequently, a continuous pulse feeding strategy was utilized in 300 L fermentor to solve the above problem and finally achieved 415.7 ± 29.2 mg L-1 ilamycin-E1/E2, representing a 30.5-fold improvement. IMPLICATION: Our work has provided a solid basis to acquire sufficient ilamycin-E1/E2 lead compounds and then support their potential anti-TB drug development.
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Antituberculosos , Antituberculosos/química , Meios de Cultura/química , FermentaçãoRESUMO
Implantation is the first step in human reproduction. Successful implantation depends on the crosstalk between embryo and endometrium. Recurrent implantation failure (RIF) is a clinical phenomenon characterized by a lack of implantation after the transfer of several embryos and disturbs approximately 10% couples undergoing in vitro fertilization and embryo transfer. Despite increasing literature on RIF, there is still no widely accepted definition or standard protocol for the diagnosis and treatment of RIF. Progress in predicting and preventing RIF has been hampered by a lack of widely accepted definitions. Most couples with RIF can become pregnant after clinical intervention. The prognosis for couples with RIF is related to maternal age. RIF can be caused by immunology, thrombophilias, endometrial receptivity, microbiome, anatomical abnormalities, male factors, and embryo aneuploidy. It is important to determine the most possible etiologies, and individualized treatment aimed at the primary cause seems to be an effective method for increasing the implantation rate. Couples with RIF require psychological support and appropriate clinical intervention. Further studies are required to evaluate diagnostic method and he effectiveness of each therapy, and guide clinical treatment.
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Implantação do Embrião , Transferência Embrionária , Gravidez , Feminino , Masculino , Humanos , Transferência Embrionária/métodos , Fertilização in vitro/métodos , Endométrio , CausalidadeRESUMO
Ilamycins E1/E2 are novel cyclic heptapeptides from Streptomyces atratus SCSIO ZH16, which have the MIC value of 9.8 nM against Mycobacterium tuberculosis H37Rv. However, the lower fermentative titer of ilamycins E1/E2 cut off further development for novel anti-TB lead drugs. In order to break the obstacle, the combinatorial strategy of medium optimization, fermentative parameters optimization, exogenous addition of metal ions, precursors, and surfactants was developed to promoted the production of ilamycins E1/E2. Addition of 1 mM ZnCl2 at 0 h, 1 g/L tyrosine at 96 h, and 2 g/L shikimic acid at 48 h increased the production of ilamycins E1/E2 from 13.51 to 762.50 ± 23.15, 721.39 ± 19.13, and 693.83 ± 16.86 mg/L, respectively. qRT-PCR results showed that the transcription levels of key genes in Embden-Meyerhof-Parnas pathway, hexose phosphate shunt pathway, and shikimic acid pathway were upregulated. In addition, the production of ilamycins E1/E2 reached 790.34 mg/L in a 5-L bioreactor by combinatorial strategy. Combinatorial strategies were used for improving ilamycins E1/E2 production in S. atratus ΔilaR and provided a sufficient basis on further clinic development.
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Excessive aluminum ions (Al3+) in acidic soil can have a toxic effect on watermelons, restricting plant growth and reducing yield and quality. In this study, we found that exogenous application of nitric oxide (NO) could increase the photochemical efficiency of watermelon leaves under aluminum stress by promoting closure of leaf stomata, reducing malondialdehyde and superoxide anion in leaves, and increasing POD and CAT activity. These findings showed that the exogenous application of NO improved the ability of watermelon to withstand aluminum stress. To further reveal the mitigation mechanism of NO on watermelons under aluminum stress, the differences following different types of treatments-normal growth, Al, and Al + NO-were shown using de novo sequencing of transcriptomes. In total, 511 differentially expressed genes (DEGs) were identified between the Al + NO and Al treatment groups. Significantly enriched biological processes included nitrogen metabolism, phenylpropane metabolism, and photosynthesis. We selected 23 genes related to antioxidant enzymes and phenylpropane metabolism for qRT-PCR validation. The results showed that after exogenous application of NO, the expression of genes encoding POD and CAT increased, consistent with the results of the physiological indicators. The expression patterns of genes involved in phenylpropanoid metabolism were consistent with the transcriptome expression abundance. These results indicate that aluminum stress was involved in the inhibition of the photosynthetic pathway, and NO could activate the antioxidant enzyme defense system and phenylpropane metabolism to protect cells and scavenge reactive oxygen species. This study improves our current understanding by comprehensively analyzing the molecular mechanisms underlying NO-induced aluminum stress alleviation in watermelons.