Production Of Bioactive Compounds Research Articles

Low microbial diversity, yeast prevalence, and nematode-trapping fungal presence in fungal colonization and leaf microbiome of Serjania erecta

Medicinal plant microbiomes undergo selection due to secondary metabolite presence. Resident endophytic/epiphytic microorganisms directly influence plant’s bioactive compound synthesis. Hypothesizing low microbial diversity in Serjania erecta leaves, we assessed leaf colonization by epiphytic and endophytic fungi. Given its traditional medicinal importance, we estimated diversity in the endophytic fungal microbiome. Analyses included scanning electron microscopy (SEM), isolation of cultivable species, and metagenomics. Epiphytic fungi interacted with S. erecta leaf tissues, horizontally transmitted via stomata/trichome bases, expressing traits for nematode trapping. Cultivable endophytic fungi, known for phytopathogenic habits, didn’t induce dysbiosis symptoms. This study confirms low leaf microbiome diversity in S. erecta, with a tendency towards more fungal species, likely due to antibacterial secondary metabolite selection. The classification of Halicephalobus sp. sequence corroborated the presence of nematode eggs on the epidermal surface of S. erecta by SEM. In addition, we confirmed the presence of methanogenic archaea and a considerable number of methanotrophs of the genus Methylobacterium. The metagenomic study of endophytic fungi highlighted plant growth-promoting yeasts, mainly Malassezia, Leucosporidium, Meyerozyma, and Hannaella. Studying endophytic fungi and S. erecta microbiomes can elucidate their impact on beneficial bioactive compound production, on the other hand, it is possible that the bioactive compounds produced by this plant can recruit specific microorganisms, impacting the biological system.

A rho-type GTPase activating protein affects the growth and development of Cordyceps cicadae.

Cordyceps cicadae is recognized for its medicinal properties, attributed to bioactive constituents like polysaccharides and adenosine, which have been shown to improve kidney and liver functions and possess anti-tumor properties. Rho GTPase activating proteins (Rho GAPs) serve as inhibitory regulators of Rho GTPases in eukaryotic cells by accelerating the GTP hydrolysis of Rho GTPases, leading to their inactivation. In this study, we explored the function of the CcRga8 gene in C. cicadae, which encodes a Rho-type GTPase activating protein. Our study found that the knockout of CcRga8 resulted in a decrease in polysaccharide levels and an increase in adenosine concentration. Furthermore, the mutants exhibited altered spore yield and morphology, fruiting body development, decreased infectivity, reduced resistance to hyperosmotic stress, oxidative conditions, and cell wall inhibitors. These findings suggest that CcRga8 plays a crucial role in the development, stress response, and bioactive compound production of C. cicadae.

Recent Advances on the Synthesis and Application of Tetrahydro‐β‐Carbolines

AbstractTetrahydro‐β‐carbolines (THβCs) also known as tryptolines serve as important structural elements in natural products and pharmaceutical compounds, and they are also utilized in drug discovery. They display diverse bioactivities, including anticancer, antifungal, antiparasitic, anti‐ischemic, anti‐inflammatory, and other activities. Besides their pharmacological and biological significance, these structural motifs are also extensively used in the production of other bioactive compounds. This review is intended to summarize recent advancements in the chemistry of this compound class, including the synthesis and the applications as organic synthetic intermediates and bioactive molecules.

Antioxidant and Anticancer Activity of Tannins Isolated from Callus Cultures of Achyranthes aspera L.

In the current study, the impact of oxidative stress induced by free radicals generated during metabolic processes was investigated. It was found to be linked to a variety of diseases due to their detrimental effects on nucleic acids and proteins. The primary focus remained on investigating the free radical-scavenging properties and potential anticancer activities of tannins found in callus cultures of A. aspera. It was observed that the induction of callus formation was notably successful when using leaf and root explants, resulting in a callus index as high as 160, as compared to stem explants in the presence of auxins. The extraction yield of callus tannins was the most abundant in chloroform extracts, although the overall antioxidant activity was comparable among chloroform, methanol, and petroleum ether callus extracts. Among these extracts, the chloroform extract from stem callus cultures grown on the MSDN medium showed the highest total antioxidant activity. Notably, tannins extracted from A. aspera leaf callus extracts displayed significant anticancer effects against the Jurket cell line. These effects were evaluated through measures such as cell viability and colony formation. The anticancer activity was notably higher in callus culture extracts as compared to the control. In summary, the results showed that in vitro biomass production can be a valuable approach for augmenting the production of bioactive compounds, such as tannins, from selected medicinal plants including A. aspera. Tannins extracted from A. aspera hold promise for their potential role in the development of new medicines.

Production and Purification of Bioactive Compounds from Ganoderma lucidum Medicinal Mushroom

Production and Purification of Bioactive Compounds from Ganoderma lucidum Medicinal Mushroom

Strategies to enhanced production of biomass and natural antioxidants of <i>Cichorium intybus</i> L. hairy roots by using nanoparticle elicitors

This study describes the influence of silver nanoparticles (AgNPs) and selenium nanoparticles (SeNPs) on the biomass and phytochemical production in the hairy root (HR) cultures of Cichorium intybus L. The HRs were grown in ½ Murashige and Skoog (MS) medium supplemented with sucrose (30 g/L) and AgNPs or SeNPs at two selected concentrations for 25 days on the shaker at 110 rpm in the dark. The results showed that SeNPs stimulated HR growth whereas AgNPs inhibited it at both concentrations used. Peroxidase activity was higher than catalase activity. In most cases, the antioxidant enzyme activities were significantly higher in the HRs elicited by elicitors than in control HRs. The activities of catalase and peroxidase reached their highest levels at approximately 16.7 and 486.4 u/mg protein, respectively. DPPH radical scavenging activity was highest in the HRs elicited by AgNPs. AgNPs (3.25 and 1.5625 mg/L) elicited HR extracts had significantly enhanced the production of total phenolic, and total flavonoid contents compared to the control HR extracts. The maximum total phenolic content was 87.04 ± 6.23 mg/g gallic equivalent, and it was 139.03 ± 3.56 mg/g ascorbic acid equivalent in total flavonoid content in the HRs elicited by AgNPs. The HRs elicited by SeNPs produce an average amount of total phenolic, flavonoid, and DPPH radical scavenging activity which were also significantly higher than those produced by control HRs. The results from our study suggested the effectiveness of the elicitation process in enhancing the root biomass, total phenolic, and flavonoid content. NPs-elicited Chicory HRs offered an effective and favorable in vitro method to improve the production of bioactive compounds for potential uses in pharmaceutical industries.

Effect of Harvest Time on Growth and Bioactive Compounds in Salvia miltiorrhiza.

Danshen (Salvia miltiorrhiza) is a perennial medicinal plant belonging to the Lamiaceae family. It is adapted to a wide range of soil pH with the potential to serve as an alternative crop in the United States. To enhance its cultivation and economic viability, it is crucial to develop production practices that maximize bioactive compound yields for danshen. The objective of this study was to investigate the effects of different harvest times on plant growth and subsequent yields of bioactive components of danshen. Three harvest times were selected (60, 120, or 180 days after transplanting [DAT]). In general, plants harvested at 180 DAT had higher plant growth index (PGI), shoot number, shoot weight, root number, maximum root length, maximum root diameter, and root weight compared to plants harvested at 60 or 120 DAT. However, plants harvested at 60 or 120 DAT had higher SPAD (Soil Plant Analysis Development) values. Plants harvested at 120 or 180 DAT had a higher content of tanshinone I, tanshinone IIA, cryptotanshinone, and salvianolic acid B compared to those harvested at 60 DAT. This study provides insights for optimizing the time of harvest of danshen to maximize plant growth and bioactive compound production.

Variations in the biochemical characteristics of Lavandula sublepidota Rech.f. in response to the foliar enrichment of green-synthesized copper nano complexes from extract of neem and jujube

Copper (Cu) is an essential micronutrient in plant physiology and biochemistry. This article synthesized copper nano complexes (Cu–NCs) based on aqueous extracts of jujube and neem leaves. The effects of foliar application of Cu-jujube and Cu-neem Cu–NCs at concentrations of 0, 10, 25, and 50 mg L−1 on the bioactive compounds, antioxidant capacity, and essential oil of the Iranian native medicinal herb Lavandula sublepidota Rech. f. was investigated. The highest levels of flavonoids and polyphenols were observed in the plants treated with Cu–NCs at 25 mg L−1. However, no superiority was observed between the two types of Cu–NCs. Furthermore, 25 mg L−1 nCu-Z and nCu-N foliar application boosted essential oil yield (48 and 52%, respectively) over control. This suggests an ideal threshold beyond which toxicity was found. Similarly, the amount of commercially significant secondary metabolites increased at 25 mg L−1 CuNCs compared to 10 and 50 mg L−1 concentrations. The maximum antioxidant activity was found in extracts of lavender that had been treated with 25 mg L−1 CuNCs. When CuNCs were applied exogenously, the extracts' antibacterial activity (MIC μg mL−1) was substantially increased against the three pathogen strains. The results suggest that CuNCs demonstrate notably greater effectiveness, particularly at an ideal concentration of 25 mg L−1, in enhancing the production of essential oil and bioactive compounds in Lavandula sublepidota Rech. f. Therefore, these findings indicate the importance of the biosynthesis of NCs using plants and measuring the phytochemical changes of lavender plants.

Biocompatible Sugar Beet Molasses Carbon Dots as Potential Elicitor to Improve Bioactive Compounds of Wheatgrass Juice

PurposeThe enrichment of health-promoting compounds in plants and foods has received significant research attention over the past years, leading researchers to use cutting-edge technologies like elicitation in agriculture and food production systems. Engineered nanoparticles (NPs) have been shown to function as effective elicitors, enhancing the synthesis of secondary metabolites. Although carbon dots (CDs) are at the forefront due to their favorable characteristics, such as being green, biocompatible, and low toxicity, their functions as elicitors have not been thoroughly investigated. The aim of this study was, therefore, to investigate the potential effect of sugar beet molasses carbon dots (SBM-CDs), characterized by their endogenous food-borne nature as elicitors, on the agronomic and bioactive compounds of wheatgrass juice obtained from hydroponically cultivated wheatgrasses.MethodsWheatgrasses were grown with and without SBM-CDs extracted from molasses at 50–200 mg L− 1 concentrations through a nutrient solution in a hydroponic system. After 7 days, wheatgrass juice was obtained by squeezing wheatgrass. The effects of SBM-CDs were investigated by assessing the agronomic parameters and bioactive compounds of wheatgrass juice.ResultsThe amount of β-carotene, vitamin E, vitamin C, and chlorophyll a increased by 150%, 84%, 25%, and 89%, respectively, with the application of 200 mg L− 1 SBM-CDs (p < 0.01) in comparison with the control group (the application without SBM-CDs). Besides, this application resulted in a 34% increase in the total quantity of tested phenolic compounds.ConclusionsThese data suggest that our biomass-derived renewable CDs may be a novel category of elicitors for enhancing the production of bioactive compounds in wheatgrass.

Exploring in vitro oryzalin-induced polyploidy in Astragalus membranaceus: implications for gene expression

This study investigates the effects of artificial in vitro polyploidisation of Astragalus membranaceus, focusing specifically on gene expression and metabolic pathway associated with the biosynthesis of calycosin and calycosin-7-O-β-D-glucoside. Using oryzalin as an antimitotic agent, we have systematically investigated different genotypic lines, under both in vitro and ex vitro conditions. Amid cases of reduced gene expression in certain lines, results showed a significant upregulation in specific lines, particularly in genotypes 16, 54, and 74. Genotype 54 showed an exceptional response, manifesting a statistically significant upregulation in all investigated genes studied under in vitro conditions (i.e. AmPAL, AmC4H and AmI3′H). Interestingly, even under ex vitro conditions after two years of greenhouse cultivation, certain lines showed significant variations in gene expression. The genotype 16, although no longer tetraploid, exhibited the highest expression levels among the examined genotypes, with statistically significant upregulation of both the AmPAL and AmC4H genes. In addition, the induced autotetraploid genotype 74 showed a significant upregulation of the AmI3′H gene and a concomitant downregulation of the AmC4H gene. These results highlight the complex regulatory mechanisms affected by the polyploidisation of A. membranaceus and provide promising avenues for manipulating gene expression to enhance the production of pharmacologically significant compounds.Key messageThis study investigates the effects of artificial polyploidisation on gene expression of Astragalus membranaceus, suggesting diverse regulatory influences for potential plant bioactive compound production.

Cytokinins enhance the metabolic activity of in vitro-grown catmint (Nepeta nuda L.)

The phytohormones cytokinins are essential mediators of developmental and environmental signaling, primarily during cell division and endophytic interactions, among other processes. Considering the limited understanding of the regulatory mechanisms that affect the growth and bioactivity of the medicinal plant Nepeta nuda (Lamiaceae), our study aimed to explore how cytokinins influence the plant's metabolic status. Exogenous administration of active cytokinin forms on in vitro N. nuda internodes stimulated intensive callus formation and de novo shoot regeneration, leading to a marked increase in biomass. This process involved an accumulation of oxidants, which were scavenged by peroxidases using phenolics as substrates. The callus tissue formed upon the addition of the cytokinin 6-benzylaminopurine (BAP) acted as a sink for sugars and phenolics during the allocation of nutrients between the culture medium and regenerated plants. In accordance, the cytokinin significantly enhanced the content of polar metabolites and their respective in vitro biological activities compared to untreated in vitro and wild-grown plants. The BAP-mediated accumulation of major phenolic metabolites, rosmarinic acid (RA) and caffeic acid (CA), corresponded with variations in the expression levels of genes involved in their biosynthesis. In contrast, the accumulation of iridoids and the expression of corresponding biosynthetic genes were not significantly affected. In conclusion, our study elucidated the mechanism of cytokinin action in N. nuda in vitro culture and demonstrated its potential in stimulating the production of bioactive compounds. This knowledge could serve as a basis for further investigations of the environmental impact on plant productivity.

Enhanced Antioxidant, Anti-Aging, Anti-Tyrosinase, and Anti-Inflammatory Properties of Vanda coerulea Griff. Ex Lindl. Protocorm through Elicitations with Chitosan.

This study aimed to investigate the effects of elicitors on Vanda coerulea Griff. Ex Lindl. protocorms to enhance bioactive compound production and evaluate their biological activities relevant to cosmeceutical applications. The protocorms were developed from the callus treated with different elicitors, including 6-benzylaminopurine (BA), methyl jasmonate (MeJA), and chitosan. Both the adult plant and protocorms were extracted by maceration in 80% methanol and investigated for their chemical compositions using high-performance liquid chromatography. The extracts were evaluated for antioxidant, anti-collagenase, anti-elastase, and anti-tyrosinase activities. In addition, anti-inflammatory properties were assessed using a real-time polymerase chain reaction. The irritation potency was evaluated using the hen's egg test-chorioallantoic membrane test. The findings revealed that protocorms treated with BA and chitosan developed a greener color, while those treated with MeJA exhibited a distinct darker coloration. Elicitation with BA and chitosan resulted in protocorms with comparable or higher levels of syringic acid, rutin, and quercin compared with the adult plant, with rutin being the most prominent identified compound. Furthermore, rutin was reported as the compound responsible for all biological activities. The chitosan-treated protocorm extract exhibited potent inhibition against oxidation, collagenase, elastase, tyrosinase, and inflammatory cytokines, along with a nonirritating effect, making it a promising candidate for cosmeceutical applications.

Cross-talk between antioxidant production and secondary metabolite biosynthesis under combined effects of ozone stress and nitrogen amendments: A case study of lemongrass

The present experiment was done to study the interactive effects of soil nitrogen (N) amendments and elevated ozone (O3) (N–O3) on a medicinal plant, lemongrass [Cymbopogon flexuosus (Steud.) (Wats.)]. The experiment used two doses of inorganic soil nitrogen (N1, recommended and N2, 1.5-times recommended dose) in open-top chambers under ambient and elevated (ambient + 15 ppb and ambient + 30 ppb) O3 conditions. To analyze various characteristics, samples were collected at 45 and 90 days after transplantation (DAT). Additionally, at 110 days after transplantation (DAT), the metabolite contents of the leaves and essential oils were analyzed. The present study aims to investigate the mechanistic approach involving the crosstalk between antioxidant production and secondary metabolite biosynthesis in lemongrass upon N–O3 interactions. The present experiment showed that N amendments can be an efficient measure to manage O3 injury in plants, along with ensuring a balance between primary and secondary metabolic pathways, thus sustaining the plant defense and production of bioactive compounds, simultaneously. Under N–O3, not only the Halliwell asada pathway was stimulated resulting in the increased activities and concentrations of antioxidant pools; the shikimate, phenylpropanoid and mevalonic acid pathways were also invigorated, producing more number and contents of secondary metabolites (SMs), compared with plants that were not treated with N doses. This study suggests that soil nitrogen amendments will improve the therapeutic qualities of lemongrass, along with the strengthening of its antioxidant machinery, upon exposure to O3 stress.

A comprehensive review on versatile microalga Tetraselmis: Potentials applications in wastewater remediation and bulk chemical production

Microalgae are considered sustainable resources for the production of biofuel, feed, and bioactive compounds. Among various microalgal genera, the Tetraselmis genus, containing predominantly marine microalgal species with wide tolerance to salinity and temperature, has a high potential for large-scale commercialization. Until now, Tetraselmis sp. are exploited at smaller levels for aquaculture hatcheries and bivalve production. However, its prolific growth rate leads to promising areal productivity and energy-dense biomass, so it is considered a viable source of third-generation biofuel. Also, microbial pathogens and contaminants are not generally associated with Tetraselmis sp. in outdoor conditions due to faster growth as well as dominance in the culture. Numerous studies revealed that the metabolite compositions of Tetraselmis could be altered favorably by changing the growth conditions, taking advantage of its acclimatization or adaptation ability in different conditions. Furthermore, the biorefinery approach produces multiple fractions that can be successfully upgraded into various value-added products along with biofuel. Overall, Tetraselmis sp. could be considered a potential strain for further algal biorefinery development under the circular bioeconomy framework. In this aspect, this review discusses the recent advancements in the cultivation and harvesting of Tetraselmis sp. for wider application in different sectors. Furthermore, this review highlights the key challenges associated with large-scale cultivation, biomass harvesting, and commercial applications for Tetraselmis sp.

Bacillus licheniformis and Bacillus velezensis from Rhizosphere of Clerodendrum infortunatum L. Promote Plant Growth and Resistance to Sclerotium rolfsii in Vigna unguiculata (L.) Walp.

In the current study, thirty bacterial strains isolated from the rhizosphere of Clerodendrum infortunatum L. were evaluated for the properties related to the plant growth promotion and disease resistance. Here, all the selected strains were screened for its antagonistic effect towards the phytopathogen Sclerotium rolfsii and also for the production of bioactive compounds known to promote the plant growth. Among these isolates, CiRb1 and CiRb16 were observed to have a broad range of plant beneficial features and were identified as Bacillus licheniformis and Bacillus velezensis respectively. Both the isolates were also demonstrated to produce the volatile organic compounds (VOCs) responsible for the growth enhancement in Brassica nigra (L.) and growth inhibition of S. rolfsii. Talc based formulations made out of both B. licheniformis and B. velezensis were further demonstrated to augment the plant growth and protection against S. rolfsii in Vigna unguiculata (L.) Walp. By the GC-MS based analysis, undecane could also be detected in the methanolic extracts prepared from both B. licheniformis and B. velezensis. Here, the selected rhizobacterial isolates were found to promote the plant growth and disease resistance through both direct and VOC mediated mechanisms. The results of the study hence reveal both B. licheniformis and B. velezensis have the potential in field application to promote the growth and control of plant diseases.

Eficiencia biológica y evaluación de los compuestos bioactivos de cepas silvestres mexicanas de Hericium erinaceus

The basidiomycete Hericium erinaceus is one of the most consumed edibles and medicinal mushrooms in the world and appreciated in traditional Chinese medicine. In Mexico it is known as lion's mane. The biological efficiency of wild strains of H. erinaceus cultivated in different substrates in the Durango region, mainly agave bagasse, a waste from mezcal production, was evaluated. The CCH003 strain from Espinazo del diablo showed the highest biological efficiency of 42.33 % and a productivity rate of 0.47 %, with a total cultivation period of 90 days and three harvests. Regarding the evaluation of bioactive compounds, the same strain obtained significant differences compared to the others, it presented the highest values for all determinations; 60 ± 0.018 mg EAG.g ES-1 in phenolic content, 4.21 ± 0.013 mg EQ.g ES-1 for flavonoids, 71.16 ± 0.002 mg EAA.g ES-1 in CAT, 0.0012 ± 0.001 mg AA.g ES-1 for by ABTS and 121 ± 0.107 µg EAG.mL-1 by DPPH. The variability of the results in the tests carried out provides information on how the type of substrate, climatological and geographical conditions and stage of maturity influence the development of the fungus, including the production of secondary metabolites, even if it is the same species. It is expected that this information will be useful to promote the use of agave bagasse as a substrate in the cultivation of H. erinaceus and thereby diversify rural activities in the region, and in the future generate new studies on the effect of conditions on the production of bioactive compounds. Keywords: agave bagasse, antioxidant, medicinal mushrooms.

Exploring the potentials of Sesuvium portulacastrum L. for edibility and bioremediation of saline soils.

Sesuvium portulacastrum L. is a flowering succulent halophyte in the ice plant family Aizoaceae. There are various ecotypes distributed in sandy coastlines and salty marshlands in tropical and subtropical regions with the common name of sea purslane. These plants are tolerant to salt, drought, and flooding stresses and have been used for the stabilization of sand dunes and the restoration of coastal areas. With the increased salinization of agricultural soils and the widespread pollution of toxic metals in the environment, as well as excessive nutrients in waterbodies, S. portulacastrum has been explored for the desalination of saline soils and the phytoremediation of metals from contaminated soils and nitrogen and phosphorus from eutrophic water. In addition, sea purslane has nutraceutical and pharmaceutical value. Tissue analysis indicates that many ecotypes are rich in carbohydrates, proteins, vitamins, and mineral nutrients. Native Americans in Florida eat it raw, pickled, or cooked. In the Philippines, it is known as atchara after being pickled. S. portulacastrum contains high levels of ecdysteroids, which possess antidiabetic, anticancer, and anti-inflammatory activities in mammals. In this review article, we present the botanical information, the physiological and molecular mechanisms underlying the tolerance of sea purslane to different stresses, its nutritional and pharmaceutical value, and the methods for its propagation and production in saline soils and waterbodies. Its adaptability to a wide range of stressful environments and its role in the production of valuable bioactive compounds suggest that S. portulacastrum can be produced in saline soils as a leafy vegetable and is a valuable genetic resource that can be used for the bioremediation of soil salinity and eutrophic water.

UV-C Enhances Phenolics Metabolism and the Production of the Related Bioactive Compounds in Green Chi-fah Chili (Capsicum annuum L. cv. Chi-fah Kiaw) Fruit

One of the fruit vegetables that is a favorite for consumers of spicy food worldwide is chili (Capsicum annuum). Thus, the external and internal quality attributes of harvested chili fruit, such as peel color and fruit antioxidants, are of interest for different cooking needs. UV-C is the shortest wavelength of ultraviolet radiation that can harm the living organisms. However, short-term exposure to this physical stress might have many advantages for crop species. This research studied the post-harvest effect of UV-C exposure for different times (0, 10, and 20 min) on the green fruit of Chi-fah chili. The results showed that the percentage of fruit with red peel color increased rapidly during storage after UV-C irradiation, especially in the 10-minute treatment 75% of fruit had red color after 6 days. UV-C treatment also promoted phenolic biosynthesis in green Chi-fah chili fruit as 10 and 20 min of UV-C exposure elevated phenolic contents in both the pulp and placenta with the maximum of 30 and 45 mg gallic acid/gFW, respectively. Exposure to 20 min of UV-C irradiation seemed to inhibit flavonoid production, whereas 10 min UV-C irradiation increased flavonoids in both the pulp and placenta (0.72 and 0.87 mg rutin/gFW, respectively). Of particular interest to the consumers, UV-C treatment could increase the capsaicin amount in green Chi-fah chili fruit. Only the fruit irradiated with UV-C for 10 min had the highest level of phenylalanine ammonia-lyase (PAL) activity in the pulp one day after storage, while the placenta had the highest level of PAL activity from day 1 to day 3. The 10 and 20 min UV-C irradiation led to the highest peroxidase (POD) activity in the pulp and the placenta, respectively. In conclusion, UV-C could be used to enhance the production of phenolics and related bioactive compounds, such as flavonoids and capsaicin in green Chi-fah chili fruit during postharvest storage.

Дослідження криптичного спеціалізованого метаболому Streptomyces cyanogenus S136

Streptomyces cyanogenus S136 is known to produce landomycin family antibiotics, particularly its largest congener, landomycin A. Except for landomycins and polyene lucensomycin, no other specialized metabolites were sourced from S136. Nevertheless, S136 genome sequencing revealed over 40 biosynthetic gene clusters (BGCs), implying underappreciated potential of this strain for the production of novel bioactive natural compounds. We set out to gain deeper insight into the specialized metabolome of this strain. First, trans­criptomic analysis of S136 grown under landomycin production conditions has been carried out, revealing that most of them are expressed at a basal level. This, likely, leads to a phenotypic silence of most of the BGCs. Nevertheless, several notable exceptions have been spotted. First of all, landomycin BGC is expressed at high level (at least 100 Transcripts Per Million mapped reads (TPM); and around 1000 TPM for minimal polyketide synthase genes lanFABC). Similarly, high levels of expression showed BGCs # 2, 4, 7 and 33, of which #2, encoding unknown saccharide, is the most dissimilar to the described precedents. RNAseq data also allowed us to delineate better the borders of several presumed BGCs. In the next phase of the work we singled out a few BGCs within S136 that appeared to be promising. First, these BGCs exhibited low similarity to the other gene clusters directing the production of known natural products. Second, the BGCs harbored cluster-situated regulatory genes that can be employed in the attempts to activate the expression of cryptic pathways. For one such BGC we constructed two plasmids for expression of several such regulatory genes and introduced them into S136 and its derivative deficient in production of landomycin A. Bioassays showed no differences in bioactivity of the recombinant strains as compared to the initial strains. Liquid chromatography coupled to mass spectrometry (LC-MS) analysis of several S. cyanogenus samples revealed the effects of genotype, growth conditions and extraction on specialized metabolome of this species, setting reference point for further stu­dies.

Parametric Study of the Effect of Increased Magnetic Field Exposure on Microalgae Chlorella vulgaris Growth and Bioactive Compound Production

Parametric Study of the Effect of Increased Magnetic Field Exposure on Microalgae Chlorella vulgaris Growth and Bioactive Compound Production