Enhancement of Carrimycin Production Via Traditional Mutagenesis with Metabolic Engineering in Streptomyces Spiramyceticus 54IA

Background: Carrimycin is a new approved class I antibiotic in China. The novel carrimycin producing strain, Streptomyces spiramyceticus 54IA, was constructed by CRISPR-Cas9 editing system without insertion of antibiotics resistant gene. The problem of low yield limits this strain in large scale fermentation. In this study, the carrimycin production was significantly improved by strain mutagenesis coupled metabolic engineering. Results: The sspD gene is responsible for degradation of triacylglycerol to provide precursors of the polyketide biosynthesis. The extra sspD gene controlled by the promoters of pks and bsm42 genes could moderately enhance carrimycin production. The Bsm42 was identified to play a pathway-specific positive regulator for carrimycin biosynthesis. Due to production of carrimycin significantly enhanced by bsm42 overexpression, the two different length promoters of bsm42 individually ligated with two reporter genes were used to monitor bsm42 expression for screening the higher carrimycin production mutants treated by plasma and ultraviolet. 47% of the 608 selected mutants had higher fermentation titer than the starting strain. The shorter promoter of bsm42 displayed more appropriate for selection of the carrimycin production improved mutants. The F2R-15 mutant had highest titer (1010±30 μg/mL), which was about 9 times higher than that of 54IA strain. Comparative analysis of transcriptome profiles of F2R-15 mutant and 54IA strains found 158 differential expression genes with more than 2 fold-changes. The up-regulated genes were associated with macrolide precursor biosynthesis, macrolide-inactivation, antibiotics transporter, oxidative phosphorylation; while the most down-regulated genes were referring to the primary metabolites synthetic genes and biosynthetic genes of other secondary metabolites. Conclusion: These results suggested that manipulation of the positive regulatory gene bsm42 and traditional mutagenesis coupled with reporter-guided mutant selection method facilitated selection of carrimycin high-yielding mutants.

1H NMR-Based Chemometrics to Gain Insights Into the Bran of Radiation-Induced Colored Wheat Mutant

Recently, wheat has attracted attention as a functional food, rather than a simple dietary energy source. Accordingly, whole-grain intake increases with an understanding of bioactive phytochemicals in bran. The development of colored wheat has drawn more attention to the value of bran owing to its nutritional quality, as well as the antioxidant properties of the colorant. The present 1H NMR-based chemometric study evaluated the compositional improvement of radiation-induced mutants in purple wheat by focusing on the predominant metabolites with high polarity. A total of 33 metabolites, including three choline derivatives, three sugar alcohols, four sugars, 13 amino acids, eight organic acids, and two nucleosides, were identified throughout the 1H NMR spectra, and quantification data were obtained for the identified metabolites via peak shape-based quantification. Principal component and hierarchical cluster analyses were conducted for performing multivariate analyses. The colored original wheat was found to exhibit improvements compared to yellow wheat in terms of the contents of primary metabolites, thus highlighting the importance of conducting investigations of polar metabolites. The chemometrics studies further revealed mutant lines with a compositional enhancement for metabolites, including lysine, proline, acetate, and glycerol.

Profiles of Essential Oils and Correlations with Phenolic Acids and Primary Metabolites in Flower Buds of Magnolia heptapeta and Magnolia denudata var. purpurascens

Magnolia flower buds are a source of herbal medicines with various active compounds. In this study, differences in the distribution and abundance of major essential oils, phenolic acids, and primary metabolites between white flower buds of Magnolia heptapeta and violet flower buds of Magnolia denudata var. purpurascens were characterised. A multivariate analysis revealed clear separation between the white and violet flower buds with respect to primary and secondary metabolites closely related to metabolic systems. White flower buds contained large amounts of monoterpene hydrocarbons (MH), phenolic acids, aromatic amino acids, and monosaccharides, related to the production of isoprenes, as MH precursors, and the activity of MH synthase. However, concentrations of β-myrcene, a major MH compound, were higher in violet flower buds than in white flower buds, possibly due to higher threonine levels and low acidic conditions induced by comparatively low levels of some organic acids. Moreover, levels of stress-related metabolites, such as oxygenated monoterpenes, proline, and glutamic acid, were higher in violet flower buds than in white flower buds. Our results support the feasibility of metabolic profiling for the identification of phytochemical differences and improve our understanding of the correlated biological pathways for primary and secondary metabolites.

Comparative GC-MS analysis of the composition of metabolites of aboveground and underground parts of Comarum palustre L

Introduction. Understanding the mechanisms of accumulation of individual groups of biologically active substances in promising types of plant raw materials and the possibility of predicting them is important for solving fundamental and applied problems of pharmaceuticals. To date, differences have been revealed in the qualitative and quantitative composition of secondary metabolites in the aboveground and underground of Comarum palustre L., however, the issue remains unstudied.Aim. Comparative metabolomic study of the composition of the primary metabolites of the aboveground and underground parts of Comarum palustre L.Materials and methods. The object of the study was the aboveground and underground parts of Comarum palustre L., harvested in the vicinity of the nursery of medicinal plants of the St. Petersburg State Chemical and Pharmaceutical University (Leningrad Region, Vsevolozhsky District, Priozerskoe Highway, 38 km) in 2019 and dried. Metabolomic studies based on GC-MS method was perfomed. A statistical analysis based on the MetaboAnalyst 5.0 platform was used.Results and discussion. Analysis of the chromatograms obtained using the GC-MS method revealed the content of 933 primary metabolites in the aboveground and underground parts of Comarum palustre L., 120 of which were identified. Using a number of statistical methods, 10 metabolites from monosaccharides, acids and alcohols, making the greatest contribution to the manifestation of differences between the studied samples, were identified.Conclusion. The study revealed the relationship between the composition of primary and secondary metabolites in medicinal plant raw materials.

Mangrove’s Plant: An updated Review on Ethnobotanical, Phytochemical and Pharmacological Potential of Barringtonia racemosa

The conventional usages and traditions of people in Barringtonia racemosa (L.) (B. racemosa) mangrove plant species in their day-to-day life and therapeutic techniques. B. racemosa (L.) belongs to family Barringtoniaceae, with single-seeded, oval-shaped fruit and a tall tree dispersed in India's east and west coasts. B. racemosa (L.), titled as putat, a fish poison tree or powder puff tree, is a precious plant species due to its medicinal values. Its fruit pulp is used in fish poison and diarrhea, asthma, coughs, analgesic and antipyretic, and has significant antitumor activity. Flavonoids and phenolic acids are the primary metabolites of the leaves and are used to reduce hypertension and purgative. In addition, the pulverized leafage, barks, and roots are used to lessen the inflammation and chickenpox. Among the phenolic compounds specified in the leaves of B. racemosa (L.) include ferulic acid, naringin, gallic acid, rutin, luteolin, protocatechuic acid, kaempferol, quercetin, and ellagic acid. Conventional remedial practices have the whole plant as a therapy for itch; the antimalarial activity is reported in roots. The bark or leaf are used in abscesses, sores, serpent bites, rat poisonings, gastric ulcers, hypertension, chickenpox. In contrast, the kernels or seeds are sourced for carcinogenic disorders and eye inflammation. The current review emphasized the ethnobotanical, phytochemistry and pharmacological activities of B. racemosa (L.) proved through various scientific facts.

Species- and Caste-Specific Gut Metabolomes in Fungus-Farming Termites

Fungus-farming termites host gut microbial communities that contribute to the pre-digestion of plant biomass for manuring the fungal mutualist, and potentially to the production of defensive compounds that suppress antagonists. Termite colonies are characterized by complex division of labor and differences in diet between termite size (minor and major) and morphological (worker and soldier) castes, and this extends to the composition of their gut microbial communities. We hypothesized that gut metabolomes should mirror these differences and tested this through untargeted LC-MS/MS analyses of three South African species of fungus-farming termites. We found distinct metabolomes between species and across castes, especially between soldiers and workers. Primary metabolites dominate the metabolomes and the high number of overlapping features with the mutualistic fungus and plant material show distinct impacts of diet and the environment. The identification of a few bioactive compounds of likely microbial origin underlines the potential for compound discovery among the many unannotated features. Our untargeted approach provides a first glimpse into the complex gut metabolomes and our dereplication suggests the presence of bioactive compounds with potential defensive roles to be targeted in future studies.

Effects of Arbuscular Mycorrhiza on Primary Metabolites in Phloem Exudates of Plantago major and Poa annua and on a Generalist Aphid

Arbuscular mycorrhiza (AM), i.e., the interaction of plants with arbuscular mycorrhizal fungi (AMF), often influences plant growth, physiology, and metabolism. Effects of AM on the metabolic composition of plant phloem sap may affect aphids. We investigated the impacts of AM on primary metabolites in phloem exudates of the plant species Plantago major and Poa annua and on the aphid Myzus persicae. Plants were grown without or with a generalist AMF species, leaf phloem exudates were collected, and primary metabolites were measured. Additionally, the performance of M. persicae on control and mycorrhizal plants of both species was assessed. While the plant species differed largely in the relative proportions of primary metabolites in their phloem exudates, metabolic effects of AM were less pronounced. Slightly higher proportions of sucrose and shifts in proportions of some amino acids in mycorrhizal plants indicated changes in phloem upload and resource allocation patterns within the plants. Aphids showed a higher performance on P. annua than on P. major. AM negatively affected the survival of aphids on P. major, whereas positive effects of AM were found on P. annua in a subsequent generation. Next to other factors, the metabolic composition of the phloem exudates may partly explain these findings.