The biosynthesis of asiaticoside and madecassoside reveals a tandem duplication-directed evolution of glycoside glycosyltransferases in the Apiales.

Certain plant species within the Apiales order accumulate triterpenoid saponins featuring a distinctive glucose-glucose-rhamnose (G-G-R) sugar chain attached at the C-28 position of the pentacyclic triterpene skeleton. Until recently, the genomic basis underlying the biosynthesis and evolution of the sugar chain remains elusive. In this study, we identified two novel glycoside glycosyltransferases (GGTs) that could sequentially install the sugar chain's second D-glucose and the third L-rhamnose during the biosynthesis of asiaticoside and madecassoside, two representative G-G-R sugar chain-containing triterpenoid saponins produced by Centella asiatica. Enzymatic assays unveiled the remarkable substrate promiscuity of the two GGTs and key residues crucial for the sugar-donor selectivity of the glucosyltransferase and rhamnosyltransferase. We further revealed syntenic tandem gene duplicates of the two GGTs in the Apiaceae and Araliaceae families, suggesting a well-conserved genomic basis underlying the sugar chain assembly that likely evolved in the early ancestors of the Apiales order. Moreover, the expression pattern of the two GGTs in pierced leaves of C. asiatica was found to be correlated with the production of asiaticoside and madecassoside, implying their involvement in the host's defense against herbivores and pathogens. Our work sheds light on the biosynthesis and evolution of complex saponin sugars, paving the way for future engineering of diverse bioactive triterpenoids with unique glycoforms.

Preface for special issue on microbiome and human health / 生物工程学报

Human microbiome is comprised of symbiotic microorganisms in the human body, whose dynamic balance is closely related to human health, and is recognized as important "organs" that can regulate immunity, metabolism and other aspects in human body, and is associated with functions of many organs including lung, intestine, vagina and brain, becoming a potential target for the treatment of cancer, coronary heart disease, neurological diseases and other difficult diseases. In recent years, with the rapid development of microbiome sequencing and analysis technology, it has become an international focus and forefront to discover the relationship between human microorganisms and many diseases, as well as target for new treatment methods. Thus, we organized this special issue and publish reviews on study methodology, human disease and microbiome as well as therapeutic strategies, and provide important information to advance microbiome research in China.

Qualitative analysis of chemical components in Lianhua Qingwen capsule by HPLC-Q Exactive-Orbitrap-MS coupled with GC-MS / 药物分析学报

The Lianhua Qingwen (LHQW) capsule is a popular traditional Chinese medicine for the treatment of viral respiratory diseases.In particular,it has been recently prescribed to treat infections caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).However,due to its complex composi-tion,little attention has been directed toward the analysis of chemical constituents present in the LHQW capsule.This study presents a reliable and comprehensive approach to characterizing the chemical constituents present in LHQW by high-performance liquid chromatography-Q Exactive-Orbitrap mass spectrometry (HPLC-Q Exactive-Orbitrap-MS) coupled with gas chromatography-mass spectrometry(GC-MS).An automated library alignment method with a high mass accuracy (within 5 ppm) was used for the rapid identification of compounds.A total of 104 compounds,consisting of alkaloids,flavonoids,phenols,phenolic acids,phenylpropanoids,quinones,terpenoids,and other phytochemicals,were suc-cessfully characterized.In addition,the fragmentation pathways and characteristic fragments of some representative compounds were elucidated.GC-MS analysis was conducted to characterize the volatile compounds present in LHQW.In total,17 compounds were putatively characterized by comparing the acquired data with that from the NIST library.The major constituent was menthol,and all the other compounds were terpenoids.This is the first comprehensive report on the identification of the major chemical constituents present in the LHQW capsule by HPLC-Q Exactive-Orbitrap-MS,coupled with GC-MS,and the results of this study can be used for the quality control and standardization of LHQW capsules.

Aglycone polyether ionophores as broad-spectrum agents inhibit multiple enveloped viruses including SARS-CoV-2 in vitro and successfully cure JEV infected mice

Infections with zoonotic viruses, such as flaviviruses, influenza virus, and the SARS-CoV-2 pandemic coronavirus constitute an increasing global risk. Hence, an urgent need exists for the development of broad-spectrum antivirals to prevent such outbreaks. Here, we show that the maduramycin and CP-80,219 aglycone polyether ionophores exhibit effective broad-spectrum antiviral activity, against various viruses, including Japanese encephalitis virus (JEV), Dengue virus (DENV), Zika virus (ZIKV), and Chikungunya virus (CHIKV), while also exhibiting promising activity against PR8 influenza virus and SARS-CoV-2. Moreover, liposome-encapsulated maduramycin and CP-80,219 provide full protection for mice from infection with JEV in vivo. Mechanistic studies suggest that aglycone polyether ionophores primarily inhibit the viral replication step without blocking endosome acidification to promote the fusion between viral and cellular membranes. The successful application of liposomes containing aglycone polyether ionophores in JEV-infected mice offers hope to the development of broad-spectrum antiviral drugs like penicillin back to 1940s.

Nanopore target sequencing for accurate and comprehensive detection of SARS-CoV-2 and other respiratory viruses

The ongoing novel coronavirus pneumonia COVID-19 outbreak in Wuhan, China, has engendered numerous cases of infection and death. COVID-19 diagnosis relies upon nucleic acid detection; however, current recommended methods exhibit high false-negative rates, low sensitivity, and cannot identify other respiratory virus infections, thereby resulting patient misdiagnosis and impeding epidemic containment. Combining the advantages of target amplification and long-read, real-time nanopore sequencing, we developed nanopore target sequencing (NTS) to detect SARS- CoV-2 and other respiratory viruses simultaneously within 6-10 h. Parallel testing with approved qPCR kits of SARS-CoV-2 and NTS using 61 nucleic acid samples from suspected COVID-19 cases confirmed that NTS identified more infected patients as positive, and could also monitor for mutated nucleic acid sequence or other respiratory virus infection in the test sample. NTS is thus suitable for contemporary COVID-19 diagnosis; moreover, this platform can be further extended for diagnosing other viruses or pathogens.

One step production of isomalto-oligosaccharides by engineered Yarrowia lipolytica yeast co-displayed β-amylase and α-transglucosidase / 生物工程学报

Isomalto-oligosaccharides (IMO) have good physiochemical properties and excellent physiological functions to make it widely used in food, medicine, feed, cosmetics and other industries. However, the procedures for industrial production of IMO are complicated. Therefore, it is necessary to develop an economical and easy-to-operate method. The genes encoding for β-amylase and α-transglucosidase were fused and co-displayed on the yeast cell surface of Yarrowia lipolytica which can convert liquefied starch to IMO in one step. The highest IMO purity of 75.3% was obtained using the displayed fusion-enzyme at 50 °C. This method showed potential application in IMO production.

Baeyer-Villiger monooxygenases in the biosynthesis of microbial secondary metabolites / 生物工程学报

Baeyer-Villiger monooxygenases, a well-studied class of flavin-dependent enzymes, catalyze the conversion of ketones to lactones or esters and the oxygenation of heteroatoms, which possesses great practical prospect in synthetic chemistry and biocatalysis. In this review, we focus on Baeyer-Villiger oxidations involved in biosynthesis of microbial secondary metabolites and discuss the characteristics of these Baeyer-Villiger oxidations and Baeyer-Villiger monooxygenases, to provide reference for the protein engineering of Baeyer-Villiger monooxygenases.

Recent Advances in Cardiac Magnetic Resonance Imaging

Cardiac magnetic resonance (CMR) imaging provides accurate anatomic information and advanced soft contrast, making it the reference standard for assessing cardiac volumes and systolic function. In this review, we summarize the recent advances in CMR sequences. New technical development has widened the use of CMR imaging beyond the simple characterization of myocardial scars and assessment of contractility. These novel CMR sequences offer comprehensive assessments of coronary plaque characterization, myocardial fiber orientation, and even metabolic activity, and they can be readily applied in clinical settings. CMR imaging is able to provide new insights into understanding the pathophysiologic process of underlying cardiac disease, and it can help physicians choose the best treatment strategies. Although several limitations, including the high cost and time-consuming process, have limited the widespread clinical use of CMR imaging so far, recent advances in software and hardware technologies have made the future more promising.

Recent Advances in Cardiac Magnetic Resonance Imaging

Cardiac magnetic resonance (CMR) imaging provides accurate anatomic information and advanced soft contrast, making it the reference standard for assessing cardiac volumes and systolic function. In this review, we summarize the recent advances in CMR sequences. New technical development has widened the use of CMR imaging beyond the simple characterization of myocardial scars and assessment of contractility. These novel CMR sequences offer comprehensive assessments of coronary plaque characterization, myocardial fiber orientation, and even metabolic activity, and they can be readily applied in clinical settings. CMR imaging is able to provide new insights into understanding the pathophysiologic process of underlying cardiac disease, and it can help physicians choose the best treatment strategies. Although several limitations, including the high cost and time-consuming process, have limited the widespread clinical use of CMR imaging so far, recent advances in software and hardware technologies have made the future more promising.

An unusual UMP C-5 methylase in nucleoside antibiotic polyoxin biosynthesis

Polyoxin is a group of structurally-related peptidyl nucleoside antibiotics bearing C-5 modifications on the nucleoside skeleton. Although the structural diversity and bioactivity preference of polyoxin are, to some extent, affected by such modifications, the biosynthetic logic for their occurence remains obscure. Here we report the identification of PolB in polyoxin pathway as an unusual UMP C-5 methylase with thymidylate synthase activity which is responsible for the C-5 methylation of the nucleoside skeleton. To probe its molecular mechanism, we determined the crystal structures of PolB alone and in complexes with 5-Br UMP and 5-Br dUMP at 2.15 Å, 1.76 Å and 2.28 Å resolutions, respectively. Loop 1 (residues 117-131), Loop 2 (residues 192-201) and the substrate recognition peptide (residues 94-102) of PolB exhibit considerable conformational flexibility and adopt distinct structures upon binding to different substrate analogs. Consistent with the structural findings, a PolB homolog that harbors an identical function from Streptomyces viridochromogenes DSM 40736 was identified. The discovery of UMP C5-methylase opens the way to rational pathway engineering for polyoxin component optimization, and will also enrich the toolbox for natural nucleotide chemistry.

Prenatal nicotine exposure induces transgenerational neuroendocrine metabolic programming alteration in second-generation rats / 中国药理学与毒理学杂志

OBJECTIVE To investigate the transgenerational effect of neuroendocrine metabolic programmed alteration in adult intrauterine growth retardation (lUGR) offspring rats with prenatal nicotine exposure. METHODS Pregnant Wistar rats were administered daily with nicotine (2 mg.kg-1 ) by sc from gestational day 11 until delivery. F1 offspring was fed with a standard diet before four groups in F2 were set up according to the cross-mating between F1 normal adult rats and nicotine-induced lUGR adult rats. CC group was mated by F1 normal adult rats, CN group by F1 normal adult male rats and lUGR adult female rats, NC group by F1 lUGR adult male rats and normal adult female rats, while NN group was mated by F1 lUGR adult rats. F2 adult rats were subjected to a fortnight ice water swimming stimulus. Blood samples were collected before and after stress and then detected for the levels of adrenocortico-tropic hormone ( ACTH), corticosterone ( CORT), glucose, triglycerides ( TG) and total cholesterol (TCH). RESULTS Before stress, the level of serum CORT in F2 male rats of NN group was decreased to 73.9% of that of the CC group (P<0.05),while the level of serum TG in F2 male rats of CN and NC groups was increased to 1.43 and 1.52 times that of the CC group, respectively ( P<0.05). Meanwhile, the level of serum TG in F2 female rats of CN, NC and NN groups was increased to 1.71, 1.80 and 1.81 times that of the CC group, respectively (P<0.05). After stress, the serum CORT gain rate in F2 male rats of CC group was -1.67%, but was 36.0% in NN group. The serum glucose level in male NC group and in female CN group was increased to 1.61 and 1.62 times that of the corresponded CC groups, respectively (P<0.01). Furthermore, the serum TG gain rate in F2 rats of each nicotine group was decreased markedly in comparison with their corresponding controls (P<0.05), ie, the serum TG gain rates in F2 male rats of CN, NC and NN groups were decreased to 46.4%, 16.7% and 7.7% of the CC group, while the serum TG gain rates in F2 female rats of these groups were decreased to 20.6%, 4.0% and 8.4% of the CC group, respectively. Compared with CC group, TCH level of females and males in NN group was decreased by 40.5% and 21.9%(P<0.01) before stress, respectively, and the TCH gain rate of females in NN group was increased by 49.7%(P<0.05) after stress. CONCLUSION The reproductive and developmental toxicities and the neuroendocrine metabolic programming alterations induced by prenatal nicotine exposure are transgenerated to F2 offspring and these effects exhibit gender and parental differences.

Aminoglycoside gentamicin research: fundamental progress and new application prospects / 生物工程学报

As an important aminoglycosides antibiotic, gentamicin has been used clinically over decades. With the development in modern biological technology, the mechanisms of gentamicin action and resistance, its biosynthesis and structural modification were studied in great depth. Meanwhile, its emerging novel bioactivities and potential applications are also under extensive exploration. Here we summarize the latest progresses and prospects towards the future development of gentamicin for more efficient and effective uses.

Twenty years hunting for sulfur in DNA

Here we tell a 20-year long story. It began with an easily overlooked DNA degradation (Dnd) phenomenon during electrophoresis and eventually led to the discovery of an unprecedented DNA sulfur modification governed by five dnd genes. This unusual DNA modification, called phosphorothioation, is the first physiological modification identified on the DNA backbone, in which the nonbridging oxygen is replaced by sulfur in a sequence selective and stereo-specific manner. Homologous dnd gene clusters have been identified in diverse and distantly related bacteria and thus have drawn immediate attention of the entire microbial scientific community. Here, we summarize the progress in chemical, genetic, enzymatic, bioinformatical and analytical aspects of this novel postreplicative DNA modification. We also discuss perspectives on the physiological functions of the DNA phosphorothioate modification in bacteria and their implications.

Characterization of the tunicamycin gene cluster unveiling unique steps involved in its biosynthesis

Tunicamycin, a potent reversible translocase I inhibitor, is produced by several Actinomycetes species. The tunicamycin structure is highly unusual, and contains an 11-carbon dialdose sugar and an α, β-1″,11'-glycosidic linkage. Here we report the identification of a gene cluster essential for tunicamycin biosynthesis by high-throughput heterologous expression (HHE) strategy combined with a bioassay. Introduction of the genes into heterologous non-producing Streptomyces hosts results in production of tunicamycin by these strains, demonstrating the role of the genes for the biosynthesis of tunicamycins. Gene disruption experiments coupled with bioinformatic analysis revealed that the tunicamycin gene cluster is minimally composed of 12 genes (tunA-tunL). Amongst these is a putative radical SAM enzyme (Tun B) with a potentially unique role in biosynthetic carbon-carbon bond formation. Hence, a seven-step novel pathway is proposed for tunicamycin biosynthesis. Moreover, two gene clusters for the potential biosynthesis of tunicamycin-like antibiotics were also identified in Streptomyces clavuligerus ATCC 27064 and Actinosynnema mirums DSM 43827. These data provide clarification of the novel mechanisms for tunicamycin biosynthesis, and for the generation of new-designer tunicamycin analogs with selective/enhanced bioactivity via combinatorial biosynthesis strategies.