Isolation of Streptomyces inhibiting multiple-phytopathogenic fungi and characterization of lucensomycin biosynthetic gene cluster.

Soil microorganisms with diverse bioactive compounds such as Streptomyces are appreciated as valuable resources for the discovery of eco-friendly fungicides. This study isolated a novel Streptomyces from soil samples collected in the organic green tea fields in South Korea. The isolation process involved antifungal activity screening around 2400 culture extracts, revealing a strain designated as S. collinus Inha504 with remarkable antifungal activity against diverse phytopathogenic fungi. S. collinus Inha504 not only inhibited seven phytopathogenic fungi including Fusarium oxysporum and Aspergillus niger in bioassays and but also showed a control effect against F. oxysporum infected red pepper, strawberry, and tomato in the in vivo pot test. Genome mining of S. collinus Inha504 revealed the presence of the biosynthetic gene cluster (BGC) in the chromosome encoding a polyene macrolide which is highly homologous to the lucensomycin (LCM), a compound known for effective in crop disease control. Through genetic confirmation and bioassays, the antifungal activity of S. collinus Inha504 was attributed to the presence of LCM BGC in the chromosome. These results could serve as an effective strategy to select novel Streptomyces strains with valuable biological activity through bioassay-based screening and identify biosynthetic gene clusters responsible for the metabolites using genome mining approach.

CRISPR-Driven Genome Engineering for Chorismate- and Anthranilate-Accumulating Corynebacterium Cell Factories.

In this study, we aimed to enhance the accumulation of chorismate (CHR) and anthranilate (ANT), key intermediates in the shikimate pathway, by modifying a shikimate over-producing recombinant strain of Corynebacterium glutamicum [19]. To achieve this, we utilized a CRISPR-driven genome engineering approach to compensate for the deletion of shikimate kinase (AroK) as well as ANT synthases (TrpEG) and ANT phosphoribosyltransferase (TrpD). In addition, we inhibited the CHR metabolic pathway to induce CHR accumulation. Further, to optimize the shikimate pathway, we overexpressed feedback inhibition-resistant Escherichia coli AroG and AroH genes, as well as C. glutamicum AroF and AroB genes. We also overexpressed QsuC and substituted shikimate dehydrogenase (AroE). In parallel, we optimized the carbon metabolism pathway by deleting the gntR family transcriptional regulator (IolR) and overexpressing polyphosphate/ATP-dependent glucokinase (PpgK) and glucose kinase (Glk). Moreover, acetate kinase (Ack) and phosphotransacetylase (Pta) were eliminated. Through our CRISPR-driven genome re-design approach, we successfully generated C. glutamicum cell factories capable of producing up to 0.48 g/l and 0.9 g/l of CHR and ANT in 1.3 ml miniature culture systems, respectively. These findings highlight the efficacy of our rational cell factory design strategy in C. glutamicum, which provides a robust platform technology for developing high-producing strains that synthesize valuable aromatic compounds, particularly those derived from the shikimate pathway metabolites.

Engineered Escherichia coli cell factory for anthranilate over-production.

Anthranilate is a key platform chemical in high demand for synthesizing food ingredients, dyes, perfumes, crop protection compounds, pharmaceuticals, and plastics. Microbial-based anthranilate production strategies have been developed to overcome the unstable and expensive supply of anthranilate via chemical synthesis from non-renewable resources. Despite the reports of anthranilate biosynthesis in several engineered cells, the anthranilate production yield is still unsatisfactory. This study designed an Escherichia coli cell factory and optimized the fed-batch culture process to achieve a high titer of anthranilate production. Using the previously constructed shikimate-overproducing E. coli strain, two genes (aroK and aroL) were complemented, and the trpD responsible for transferring the phosphoribosyl group to anthranilate was disrupted to facilitate anthranilate accumulation. The genes with negative effects on anthranilate biosynthesis, including pheA, tyrA, pabA, ubiC, entC, and trpR, were disrupted. In contrast, several shikimate biosynthetic pathway genes, including aroE and tktA, were overexpressed to maximize glucose uptake and the intermediate flux. The rationally designed anthranilate-overproducing E. coli strain grown in an optimized medium produced approximately 4 g/L of anthranilate in 7-L fed-batch fermentation. Overall, rational cell factory design and culture process optimization for microbial-based anthranilate production will play a key role in complementing traditional chemical-based anthranilate production processes.

New logarithm-based discrimination formula for differentiating thalassemia trait from iron deficiency anemia in pregnancy.

BACKGROUND: Thalassemia trait (TT) and iron deficiency anemia (IDA) are the most common conditions of microcytic hypochromic anemia (MHA) in pregnant women. Accurate discrimination between TT and IDA is an important issue, and better methods are urgently needed. Although considerable RBC formulas and indices have been developed since 1973, distinguishing between IDA and TT is still a challenging problem due to the diversity of various anemic populations. To address this problem, we assessed the diagnostic function of 43 different differential formulas in patients with microcytic anemia by using accuracy measures and recommending a new log-based differential formula. METHODS: The data of 430 pregnant women (229 with TT and 201 with IDA) were enrolled, and 44 formula performances were evaluated with receiver operating characteristic (ROC) analysis. RESULTS: The newly introduced logarithm-based formula XS-1 performs better than the general discriminant index with sensitivity and specificity of 82.10 and 89.05, which are better than other formulas. In the pregnant population, the Shine and Lal and Roth..SVM. formulas have shown excellent performance, while other formulas showed poorer discriminative abilities in our study than in the original authors. CONCLUSION: The logarithm-based formula XS-1 can be used to screen thalassemia and iron deficiency anemia during the first trimester. Considering the particularity of pregnancy, medical personnel in different regions should choose a screening formula similar to that of the local region and population when identifying thalassemia in pregnancy. Any formula should be independently verified locally before use. For the convenience of the health care team and experimental scientists, a web-based tool has been established at http://yyy.yiyiy.top/XS-1/ by which users can easily get their desired screening test result without going through the underlying mathematical and computational details.

Active Ingredients of Reduning Injection Maintain High Potency against SARS-CoV-2 Variants / 中国结合医学杂志

OBJECTIVE@#To investigate the anti-coronavirus potential and the corresponding mechanisms of the two ingredients of Reduning Injection: quercetin and luteolin.@*METHODS@#A pseudovirus system was designed to test the efficacy of quercetin and luteolin to inhibit SARS-CoV-2 infection and the corresponding cellular toxicity. Luteolin was tested for its activities against the pseudoviruses of SARS-CoV-2 and its variants. Virtual screening was performed to predict the binding sites by Autodock Vina 1.1.230 and PyMol. To validate docking results, surface plasmon resonance (SPR) was used to measure the binding affinity of the compounds with various proteins of the coronaviruses. Quercetin and luteolin were further tested for their inhibitory effects on other coronaviruses by indirect immunofluorescence assay on rhabdomyosarcoma cells infected with HCoV-OC43.@*RESULTS@#The inhibition of SARS-CoV-2 pseudovirus by luteolin and quercetin were strongly dose-dependent, with concentration for 50% of maximal effect (EC50) of 8.817 and 52.98 µmol/L, respectively. Their cytotoxicity to BHK21-hACE2 were 177.6 and 405.1 µmol/L, respectively. In addition, luetolin significantly blocked the entry of 4 pseudoviruses of SARS-CoV-2 variants, with EC50 lower than 7 µmol/L. Virtual screening and SPR confirmed that luteolin binds to the S-proteins and quercetin binds to the active center of the 3CLpro, PLpro, and helicase proteins. Quercetin and luteolin showed over 99% inhibition against HCoV-OC43.@*CONCLUSIONS@#The mechanisms were revealed of quercetin and luteolin inhibiting the infection of SARS-CoV-2 and its variants. Reduning Injection is a promising drug for COVID-19.

Comparison of characteristic chromatogram and the contents of multiple indicator components of Morus alba decoction powder and decoction at different decoction time / 中国药房

OBJECTIVE To compare characteristic chromatogram and the contents of multiple indicator components of Morus alba decoction powder and decoction at different decoction time， and to provide experimental basis for the development of M. alba decoction. METHODS Taking decoction powder and decoction at different decoction time as subject， HPLC characteristic chromatogram of 2 kinds of samples were established with Similarity Evaluation Software System of TCM Chromatographic Fingerprint （2012 version）， and similarity evaluation was performed. The contents of mulberroside A， geniposide， berberine， baicalin， quercetin and luteolin in decoction powder and decoction were determined by HPLC. The contents of each indicator component and the change of total content were as the evaluation indexes to compare the difference between the two substances during decoction. RESULTS The similarities of characteristic chromatogram of the two substances ranged from 0.943 to 1.000 and 0.975 to 0.998 at different decoction time， respectively. Six indicator components of the decoction powder dissolved faster and had higher contents. The contents of each indicator component in the decoction powder when decocting at 20 minutes was 1.1-1.5 times of the decoction when decocting at 50 min， and the total content in the decoction powder was 1.2 times of the decoction. CONCLUSIONS Compared with decoction， M. alba decoction powder has the advantages of shortening the decoction time and saving traditional Chinese medicine resources. The results of this study lay a research foundation for “Zungu” to develop its preparation.

High-risk human papillomavirus negative cervical lesions in the cervical cancer screening population / 中国医师杂志

Objective:To investigate the incidence of high-risk human papillomavirus (hrHPV) negative cervical lesions in the screening population, and based on this, to preliminarily evaluate the potential harm (missed diagnosis) and benefits (reduced colposcopy referral) of HPV primary screening compared to combined screening so as to provide reference for the selection of cervical cancer primary screening methods.Methods:This study was a single center cross-sectional study. Women who underwent joint screening [hrHPV typing test combined with cervical liquid based cytology test (LCT)] at the Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology from January 1, 2018 to December 31, 2019 were included in the cervical cancer screening. The proportion of hrHPV negative cytological abnormalities and cervical lesions in the population was analyzed and the theoretical colposcopy referral rate of the combined screening and HPV initial screening protocol was calculated. In the population with cervical pathological results, the number of colposcopy examinations required for the diagnosis of cervical intraepithelial neoplasia grade 2 and above (CIN2+ ) was calculated.Results:A total of 35 321 screened women were included. The overall incidence of hrHPV infection, LCT abnormalities and severe LCT abnormalities in the population was 17.13%(6 051/35 321), 18.07%(6 384/35 321), and 3.97%(1 402/35 321), respectively. The negative rate of hrHPV in women with severe cervical cytology abnormalities was as high as 51.28%(719/1 402), and in CIN2+ lesions diagnosed by cervical biopsy, hrHPV negative accounted for 7.15% (49/685). The theoretical colposcopy referral rates for combined screening and initial HPV screening were 11.28%(3 985/35 321) and 8.33%(2 943/35 321), respectively, with an average diagnosis of CIN2+ requiring 3.51 and 2.81 colposcopy examinations, respectively.Conclusions:In the opportunistic screening population, the proportion of hrHPV negative CIN2+ lesions cannot be ignored, and the HPV initial screening strategy may cause missed diagnosis of these lesions. However, compared to combined screening, HPV initial screening has the potential to improve the efficiency of colposcopy. These results suggest that we should carefully choose the HPV initial screening plan.

Fibrinogen and antithrombin III are associated with in-hospital mortality among critically ill patients with acute kidney injury.

OBJECTIVES: Coagulation factors participates in the inflammatory cascade, known to play a crucial role in the development of acute kidney injury (AKI). Thus, it's likely that some factors may be associated with AKI. Among them, low levels of fibrinogen and antithrombin III (ATIII) activity have been proved to increase mortality in patients with sepsis. Moreover, they are also reported to be associated with higher incidence of AKI. However, the association between coagulation parameters, especially fibrinogen and ATIII, and prognosis of AKI has not been examined. METHODS: Data were acquired from Multiparameter Intelligent Monitoring in Intensive Care Database IV (MIMIC-IV) version 1.0. Cox proportional hazards regression model was used to estimate the relationship between coagulation parameters and in-hospital mortality in critically ill patients with AKI. Subgroup analysis was also conducted to assess the robustness of the association. Restricted cubic spline (RCS) curve was utilized to examine the nonlinear relationships between fibrinogen or ATIII and in-hospital mortality. Kaplan-Meier method was used to estimate cumulative incidence of mortality by fibrinogen or ATIII levels. Receiver-operating characteristic (ROC) curve was plotted and area under curve was calculated to evaluate predictive ability of fibrinogen or ATIII. RESULTS: A total of 5914 eligible patients were enrolled in fibrinogen cohort study and 115 patients were eligible for ATIII cohort study. The baseline of low fibrinogen (<150 mg/dL) or ATIII (<80%) activity was associated with significantly higher in-hospital mortality (fibrinogen HR [95% CIs] 2.01 [1.79, 2.27]; ATIII 3.73 [1.11, 12.54]). The HR [95% CIs] of low fibrinogen remained significant 1.29 (1.13, 1.48) in multivariate analysis. The RCS curve showed nearly linear relationship. Subgroup analysis also proved the robustness of the association between fibrinogen and in-hospital mortality. Kaplan-Meier survival curve and ROC demonstrated the predictive capability of fibrinogen and ATIII. CONCLUSION: Low fibrinogen is an independent predictor of in-hospital mortality in critically ill patients with AKI. Low ATIII activity is also likely to impact the risk of in-hospital death.

BAC cloning and heterologous expression of a giant biosynthetic gene cluster encoding antifungal neotetrafibricin in streptomyces rubrisoli.

Polyene natural products including nystatin A1, amphotericin B, ECO-02301, and mediomycin belong to a large family of valuable antifungal polyketide compounds typically produced by soil actinomycetes. A previous study (Park et al., Front. Bioeng. Biotechnol., 2021, 9, 692340) isolated Streptomyces rubrisoli Inha501 with strong antifungal activity and analyzed a large-sized biosynthetic gene cluster (BGC) of a linear polyene compound named Inha-neotetrafibricin (I-NTF) using whole genome sequencing and bioinformatics. In the present study, an entire I-NTF BGC (∼167 kb) was isolated through construction and screening of Streptomyces BAC library. Overexpression of the cloned I-NTF BGC in the wild-type S. rubrisoli Inha501 and its heterologous expression in S. lividans led to 2.6-fold and 2.8-fold increase in I-NTF yields, respectively. The qRT-PCR confirmed that the transcription levels of I-NTF BGC were significantly increased in both homologous and heterologous hosts containing the BAC integration of I-NTF BGC. In addition, the I-NTF aglycone-producing strains were constructed by a target-specific deletion of glycosyltransferase gene present in I-NTF BGC. A comparison of the in vitro biological activities of I-NTF and I-NTF aglycone confirmed that the rhamnose sugar motif of I-NTF plays a critical role in both antifungal and antibacterial activities. These results suggest that the Streptomyces BAC cloning of a large-sized natural product BGC is a valuable approach for natural product titer improvement and biological activity screening of natural product in actinomycetes.

Isolation and Characterization of Engineered Nucleoside Deoxyribosyltransferase with Enhanced Activity Toward 2'-Fluoro-2'-Deoxynucleoside.

Nucleoside deoxyribosyltransferase (NDT) is an enzyme that replaces the purine or pyrimidine base of 2'-deoxyribonucleoside. This enzyme is generally used in the nucleotide salvage pathway in vivo and synthesizes many nucleoside analogs in vitro for various biotechnological purposes. Since NDT is known to exhibit relatively low reactivity toward nucleoside analogs such as 2'-fluoro-2'-deoxynucleoside, it is necessary to develop an enhanced NDT mutant enzyme suitable for nucleoside analogs. In this study, molecular evolution strategy via error-prone PCR was performed with ndt gene derived from Lactobacillus leichmannii as a template to obtain an engineered NDT with higher substrate specificity to 2FDU (2'-fluoro-2'-deoxyuridine). A mutant library of 214 ndt genes with different sequences was obtained and performed for the conversion of 2FDU to 2FDA (2'-fluoro-2'-deoxyadenosine). The E. coli containing a mutant NDT, named NDTL59Q, showed 1.7-fold (at 40°C) and 4.4-fold (at 50°C) higher 2FDU-to-2FDA conversions compared to the NDTWT, respectively. Subsequently, both NDTWT and NDTL59Q enzymes were over-expressed and purified using a His-tag system in E. coli. Characterization and enzyme kinetics revealed that the NDTL59Q mutant enzyme containing a single point mutation of leucine to glutamine at the 59th position exhibited superior thermal stability with enhanced substrate specificity to 2FDU.

Streptomyces BAC Cloning of a Large-Sized Biosynthetic Gene Cluster of NPP B1, a Potential SARS-CoV-2 RdRp Inhibitor.

As valuable antibiotics, microbial natural products have been in use for decades in various fields. Among them are polyene compounds including nystatin, amphotericin, and nystatin-like Pseudonocardia polyenes (NPPs). Polyene macrolides are known to possess various biological effects, such as antifungal and antiviral activities. NPP A1, which is produced by Pseudonocardia autotrophica, contains a unique disaccharide moiety in the tetraene macrolide backbone. NPP B1, with a heptane structure and improved antifungal activity, was then developed via genetic manipulation of the NPP A1 biosynthetic gene cluster (BGC). Here, we generated a Streptomyces artificial chromosomal DNA library to isolate a large-sized NPP B1 BGC. The NPP B1 BGC was successfully isolated from P. autotrophica chromosome through the construction and screening of a bacterial artificial chromosome (BAC) library, even though the isolated 140-kb BAC clone (named pNPPB1s) lacked approximately 8 kb of the right-end portion of the NPP B1 BGC. The additional introduction of the pNPPB1s as well as co-expression of the 32-kb portion including the missing 8 kb led to a 7.3-fold increase in the production level of NPP B1 in P. autotrophica. The qRT-PCR confirmed that the transcription level of NPP B1 BGC was significantly increased in the P. autotrophica strain containing two copies of the NPP B1 BGCs. Interestingly, the NPP B1 exhibited a previously unidentified SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) inhibition activity in vitro. These results suggest that the Streptomyces BAC cloning of a large-sized, natural product BGC is a valuable approach for titer improvement and biological activity screening of natural products in actinomycetes.

Respiratory mucosal vaccination of peptide-poloxamine-DNA nanoparticles provides complete protection against lethal SARS-CoV-2 challenge

The ongoing SARS-CoV-2 pandemic represents a brutal reminder of the continual threat of mucosal infectious diseases. Mucosal immunity may provide robust protection at the predominant sites of SARS-CoV-2 infection. However, it remains unclear whether respiratory mucosal administration of DNA vaccines could confer protective immune responses against SARS-CoV-2 challenge due to the insurmountable barriers posed by the airway. Here, we applied self-assembled peptide-poloxamine nanoparticles with mucus-penetrating properties for pulmonary inoculation of a COVID-19 DNA vaccine (pSpike/PP-sNp). Not only displays the pSpike/PP-sNp superior gene-transfection and favorable biocompatibility in the mouse airway, but pSpike/PP-sNp promotes a tripartite immunity consisting of systemic, cellular and mucosal immune responses that are characterized by mucosal IgA secretion, high levels of neutralizing antibodies, and resident memory phenotype T-cell responses in the lungs of mice. Most importantly, pSpike/PP-sNp completely eliminates SARS-CoV-2 infection in both upper and lower respiratory tracts and enables 100% survival rate of mice following lethal SARS-CoV-2 challenge. Our findings indicate PP-sNp might be a promising platform in mediating DNA vaccines to elicit all-around mucosal immunity against SARS-CoV-2.

Sperm-specific protein ACTL7A as a biomarker for fertilization outcomes of assisted reproductive technology / 亚洲男科学杂志(英文版)

Obtaining high-quality embryos is one of the key factors to improve the clinical pregnancy rate of assisted reproductive technologies (ART). So far, the clinical evaluation of embryo quality depends on embryo morphology. However, the clinical pregnancy rate is still low. Therefore, new indicators are needed to further improve the evaluation of embryo quality. Several studies have shown that the decrease of sperm-specific protein actin-like 7A (ACTL7A) leaded to low fertilization rate, poor embryo development, and even infertility. The aim of this study was to study whether the different expression levels of ACTL7A on sperm can be used as a biomarker for predicting embryo quality. In this study, excluding the factors of severe female infertility, a total of 281 sperm samples were collected to compare the ACTL7A expression levels of sperms with high and low effective embryo rates and analyze the correlation between protein levels and in-vitro fertilization (IVF) laboratory outcomes. Our results indicated that the ACTL7A levels were significantly reduced in sperm samples presenting poor embryo quality. Furthermore, the protein levels showed a significant correlation with fertilization outcomes of ART. ACTL7A has the potential to be a biomarker for predicting success rate of fertilization and effective embryo and the possibility of embryo arrest. In conclusion, sperm-specific protein ACTL7A has a strong correlation with IVF laboratory outcomes and plays important roles in fertilization and embryo development.

Shikimate Metabolic Pathway Engineering in Corynebacterium glutamicum.

Shikimate is a key high-demand metabolite for synthesizing valuable antiviral drugs, such as the anti-influenza drug, oseltamivir (Tamiflu). Microbial-based strategies for shikimate production have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. In this study, a microbial cell factory using Corynebacterium glutamicum was designed to overproduce shikimate in a fed-batch culture system. First, the shikimate kinase gene (aroK) responsible for converting shikimate to the next step was disrupted to facilitate the accumulation of shikimate. Several genes encoding the shikimate bypass route, such as dehydroshikimate dehydratase (QsuB), pyruvate kinase (Pyk1), and quinate/shikimate dehydrogenase (QsuD), were disrupted sequentially. An artificial operon containing several shikimate pathway genes, including aroE, aroB, aroF, and aroG were overexpressed to maximize the glucose uptake and intermediate flux. The rationally designed shikimate-overproducing C. glutamicum strain grown in an optimized medium produced approximately 37.3 g/l of shikimate in 7-L fed-batch fermentation. Overall, rational cell factory design and culture process optimization for the microbial-based production of shikimate will play a key role in complementing traditional plant-derived shikimate production processes.

Screening and Isolation of a Novel Polyene-Producing Streptomyces Strain Inhibiting Phytopathogenic Fungi in the Soil Environment.

Microbial-based eco-friendly biological substances are needed to protect crops from phytopathogenic fungi and replace toxic chemical fungicides that cause serious environmental issues. This study screened for soil antifungal Streptomyces strains, which produce rich, diverse, and valuable bioactive metabolites in the soil environment. Bioassay-based antifungal screening of approximately 2,400 Streptomyces strains led to the isolation of 149 strains as tentative antifungal producers. One Streptomyces strain showing the most potent antifungal activities against Candida albicans and Fusarium oxysporum was identified as a putative anti-phytopathogenic soil isolate that is highly homologous to Streptomyces rubrisoli (named S. rubrisoli Inha 501). An in vitro antifungal assay, pot-test, and field-test against various phytopathogenic fungi confirmed that S. rubrisoli Inha 501 is a potential novel phytopathogenic fungicide producer to protect various crops in the soil environment. Whole-genome sequencing of S. rubrisoli Inha 501 and an anti-SMASH genome mining approach revealed an approximately 150-kb polyene biosynthetic gene cluster (BGC) in the chromosome. The target compound isolation and its BGC analysis confirmed that the giant linear polyene compound exhibiting the anti-phytopathogenic activity in S. rubrisoli Inha 501 was highly homologous to the previously reported compound, neotetrafibricin A. These results suggest that a bioassay-based screening of a novel antifungal Streptomyces strain followed by its genome mining for target compound BGC characterization would be an efficient approach to isolating a novel candidate phytopathogenic fungicide that can protect crops in the soil environment.

Artificial cell factory design for shikimate production in Escherichia coli.

Shikimate is a key intermediate in high demand for synthesizing valuable antiviral drugs, such as the anti-influenza drug and oseltamivir (Tamiflu®). Microbial-based shikimate production strategies have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. Although shikimate biosynthesis has been reported in several engineered bacterial species, the shikimate production yield is still unsatisfactory. This study designed an Escherichia coli cell factory and optimized the fed-batch culture process to achieve a high titer of shikimate production. Using the previously constructed dehydroshikimate (DHS)-overproducing E. coli strain, two genes (aroK and aroL) responsible for converting shikimate to the next step were disrupted to facilitate shikimate accumulation. The genes with negative effects on shikimate biosynthesis, including tyrR, ptsG, and pykA, were disrupted. In contrast, several shikimate biosynthetic pathway genes, including aroB, aroD, aroF, aroG, and aroE, were overexpressed to maximize the glucose uptake and intermediate flux. The shiA involved in shikimate transport was disrupted, and the tktA involved in the accumulation of both PEP and E4P was overexpressed. The rationally designed shikimate-overproducing E. coli strain grown in an optimized medium produced approximately 101 g/l of shikimate in 7-l fed-batch fermentation, which is the highest level of shikimate production reported thus far. Overall, rational cell factory design and culture process optimization for microbial-based shikimate production will play a key role in complementing traditional plant-derived shikimate production processes.

Etiological diagnostic value of metagenomics next-generation sequencing in liver abscess / 中华急诊医学杂志

Objective:To explore the value of metagenomic next-generation sequencing (mNGS) in the pathogen diagnosis of liver abscess.Methods:A perspective study was performed in 35 hospitalized patients with liver abscess in Department of Emergency Medicine, Zhongshan Hospital, Fudan University from February 2020 to April 2021. Blood samples and abscess drainage fluid samples were detected by routine microbial culture and mNGS. Patients were divided into two groups according to whether they had septic shock or not. SPSS 25.0 was used for statistical analysis.Results:The overall positive rate of mNGS in blood samples and drainage fluid samples was significantly higher than that of routine microbial culture methods (blood: 67.6% vs. 15.2%, P<0.05; Drainage fluid: 100% vs. 55.2%, P<0.05). In 35 patients with liver abscess, 71.4% of the pathogens were Klebsiella pneumoniae. The sequence number of pathogenic pathogens detected by mNGS in abscess drainage fluid samples of patients in the shock group was significantly higher than that in the non-shock group ( P<0.05). Conclusions:The mNGS can quickly and accurately detect the pathogen of liver abscess, which can provide important etiological diagnostic for clinical treatment.

The feasibility and effectiveness of sentinel lymph node detection in ovarian neoplasms: a systematic review / 中国医师杂志

Objective:To evaluate the feasibility and effectiveness of sentinel lymph node (SLN) detection in the ovarian neoplasms.Methods:A search of the literature describing ovarian SLN was performed using China National Knowledge Infrastructure (CNKI), WANFANG DATA, VIP, PubMed, Embase, web of science, Cochrane library from 2000.01.01 to 2020.07.29. The quality evaluation and data extraction of the included literature were conducted, and the development rate, sensitivity and negative predictive value of SLN were calculated.Results:Eight prospective single-arm studies were included, with heterogeneity I2=57.41%>50%, and the P<0.1. A total of 96 patients with ovarian cancer [Stage International Federation of Gynecology and Obstetrics (FIGO)Ⅰ-Ⅱ] were included, of whom 93 completed systematic pelvic and para-aortic lymphadenectomy after SLN detection. The most common tracers were technetium-99m radioactive colloid ( 99Tc m), blue dye or indocyanine green (ICG), and the most common injection sites were the infundibulopelvic ligaments and the proper ovarian ligaments. The SLN detection rate was 88.5%(85/96) and the average number was 2-3. SLN was found in the ipsilateral or contralateral regions of the tumor, 40.8%(31/76) was found only in the para-aortic, 14.5%(11/76) was found only in the pelvic, and 44.7%(34/76) was found only in the para-aortic and pelvic region. The sensitivity was 90.9%(10/11) and the negative predictive value was 98.8%(82/83) of lymph node metastasis. Conclusions:SLN detection for ovarian neoplasms is feasible, and whether it can effectively predict lymph node status of ovarian cancer still needs large sample, multi-center, prospective clinical studies to further verify.

Clinical significance of RAD51C and its contribution to ovarian carcinogenesis.

AIM: The underlying mechanisms of chemoresistance-induced recurrence of ovarian carcinoma are largely unknown. The purpose of this study was to investigate the clinical significance of RAD51C and its role in ovarian tumorigenesis and progression. METHODS: 60 cases of ovarian epithelial tumors (30 benign and 30 malignant tumors, respectively) were enrolled from 2014 to 2016. Immunohistochemistry was used to evaluate RAD51C expression in tumor tissues, and RT-PCR was employed to test RAD51C mRNA levels in SKOV3, A2780, and CAOV3 cell lines. Targeted knockdown of RAD51C was achieved with siRNA to explore the changes of cell proliferation, migration, and apoptosis. RESULTS: RAD51C protein level in carcinoma tissues, especially in the high-grade group (P<0.001), was significantly higher than that of benign tumors and associated with pathological type, stage, and overall survival (P<0.05). Downregulation of RAD51C promoted apoptosis and decreased cell survival rate and migration. CONCLUSIONS: Our results supported that RAD51C contributes to the progression of ovarian carcinoma, suggesting its promising application as an independent prognostic marker for diagnosis and treatment.

Stimulated Biosynthesis of an C10-Deoxy Heptaene NPP B2 via Regulatory Genes Overexpression in Pseudonocardia autotrophica.

Polyene macrolides, such as nystatin A1, amphotericin B, and NPP A1, belong to a large family of valuable antifungal polyketide compounds that are typically produced by soil actinomycetes. Previously, NPP B1, a novel NPP A1 derivative harboring a heptaene core structure, was generated by introducing two amino acid substitutions in the putative NADPH-binding motif of the enoyl reductase domain in module 5 of the NPP A1 polyketide synthase in Pseudonocardia autotrophica. This derivative showed superior antifungal activity to NPP A1. In this study, another novel derivative called NPP B2 was developed, which lacks a hydroxyl group at the C10 position by site-specific gene disruption of the P450 hydroxylase NppL. To stimulate the extremely low expression of the NPP B2 biosynthetic pathway genes, the 32-kb NPP-specific regulatory gene cluster was overexpressed via site-specific chromosomal integration. The extra copy of the six NPP-specific regulatory genes led to a significant increase in the NPP B2 yield from 0.19 to 7.67 mg/L, which is the highest level of NPP B2 production ever achieved by the P. autotrophica strain. Subsequent in vitro antifungal activity and toxicity studies indicated that NPP B2 exhibited similar antifungal activity but significantly lower hemolytic toxicity than NPP B1. These results suggest that an NPP biosynthetic pathway refactoring and overexpression of its pathway-specific regulatory genes is an efficient approach to stimulating the production of an extremely low-level metabolite, such as NPP B2 in a pathway-engineered rare actinomycete strain.