Production Of Bioactive Compounds Research Articles

Phytohormone-induced changes in growth, physiology, and biochemistry of Aurantiochytrium sp. for sustainable bioproduction

The study aimed to assess the effects of nine combinations of phytohormones, salicylic acid (SA), gibberellic acid (GA), and jasmonic acid (JA) on the growth, physiology, and biochemistry of Aurantiochytrium sp. Parameters like optical density (OD), biomass, protein content, hydrogen peroxide (H2O2), malondialdehyde (MDA), catalase activity (CAT), and gene expression (malic enzyme (ME) and acetyl-CoA carboxylase (ACCase)) were assessed at various cultivation stages (24, 48, 72, and 96 h). The research also analyzed fatty acid composition, unsaturated fatty acids (UFA), saturated fatty acids (SFA), and the UFA to SFA ratio (USS) to understand the biochemical changes induced by phytohormones. Results demonstrated that modifying phytohormone concentrations significantly affected the characteristics of the microalgae, particularly in correlation with different growth stages, emphasizing the necessity of precise control of phytohormone levels for optimizing cultivation conditions and enhancing bioactive compound production in Aurantiochytrium sp.

A review on endophytic bacteria of orchids: functional roles toward synthesis of bioactive metabolites for plant growth promotion and disease biocontrol.

In this review, we have discussed the untapped potential of orchid endophytic bacteria as a valuable reservoir of bioactive metabolites, offering significant contributions to plant growth promotion and disease protection in the context of sustainable agriculture. Orchidaceae is one of the broadest and most diverse flowering plant families on Earth. Although the relationship between orchids and fungi is well documented, bacterial endophytes have recently gained attention for their roles in host development, vigor, and as sources of novel bioactive compounds. These endophytes establish mutualistic relationships with orchids, influencing plant growth, mineral solubilization, nitrogen fixation, and protection from environmental stress and phytopathogens. Current research on orchid-associated bacterial endophytes is limited, presenting significant opportunities to discover new species or genetic variants that improve host fitness and stress tolerance. The potential for extracting bioactive compounds from these bacteria is considerable, and optimization strategies for their sustainable production could significantly enhance their commercial utility. This review discusses the methods used in isolating and identifying endophytic bacteria from orchids, their diversity and significance in promoting orchid growth, and the production of bioactive compounds, with an emphasis on their potential applications in sustainable agriculture and other sectors.

Bioactive Compound Production in Yerba Mate Clones with Increasing Nitrogen in Semi-Hydroponic System

Bioactive Compound Production in Yerba Mate Clones with Increasing Nitrogen in Semi-Hydroponic System

Propagation and molecular analysis in Dioscorea: a bibliometric review

Species of the genus Dioscorea, popularly called yams, are notable primarily for their nutritional value and the production of bioactive compounds. Considering the importance of this genus for the food and pharmaceutical industries, the present study aimed to understand the state of the art in the area of propagation and molecular characterization of the genus, based on bibliometric analysis. Bibliometrics was the basic methodological tool used, and the data were sourced from the Scopus® and Web of ScienceTM databases. A total of 69 publications on the propagation of the Dioscorea genus were analyzed. The average number of publications per year was 4.69, with the highest number of publications observed in 2011 and an annual growth rate of 4.25%. The most developed themes were those related to propagation through in vitro cultivation. Regarding molecular characterization, 44 publications were analyzed. The average number of publications was 5.37, with the highest number of publications observed in 2017 and an annual growth rate of 7.11%. The most important themes were related to the genetic diversity of species of the genus. This review maps the existing studies and identifies gaps in the research field on the propagation and molecular characterization of species of the genus Dioscorea.

Postbiotic emissaries: a comprehensive review on the bioprospecting and production of bioactive compounds by Enterococcus species

SummaryEnterococcus species have been acknowledged for their diverse metabolic capabilities, resulting in a wide array of bioactive compounds that show promise for therapeutic use. This article presents a thorough examination of the exploration and synthesis of bioactive compounds by Enterococcus species. It encompasses the taxonomy, natural habitat, and significance in the biotechnology of Enterococcus, emphasising the various bioactive compounds it produces, including antibacterial, immunomodulatory, and antioxidant agents. Strategies for exploring potential bioactivities, encompassing isolation methodologies and screening techniques, are discussed. The biotechnological synthesis of bioactive compounds derived from Enterococcus via fermentation processes, optimisation approaches, and scaling methodologies is expounded. Moreover, the utilisation of these bioactive compounds in functional foods, pharmaceuticals, and agriculture, alongside considerations of safety and regulatory aspects, is examined. The review concludes with future perspectives and challenges in the field of Enterococcus‐derived bioactive compounds.

Strategies for improvement of bioactive compounds production using microalgal consortia: An emerging concept for current and future perspective

In recent times, microalgae have been recognized as one of the most potential sources of biomolecules with therapeutic potential. Microalgae are rich sources of polyunsaturated fatty acids, proteins, carbohydrates, carotenoids, and vitamins. These compounds have significant anticancer, antioxidant, anti-aging, antidiabetic, hepatoprotective, and anti-inflammatory potentials. Until now, monoculture of microalgae has been the most preferred way to produce these compounds. However, this method faces the challenge of low biomass and biomolecule production and a high risk of contamination. Controlled symbiotic co-culture of microalgae with suitable microorganisms can overcome these challenges. Therefore, it is crucial to explore the compatibility of microalgae with other microorganisms to develop novel consortia to enhance biomass and biomolecule production. The article comprehensively reviews the strategies for the improvement of bioactive compound production using microalgal consortia (SIBCP-MC) viz. microalgae, fungi, bacteria, and cyanobacteria. It also discusses the mechanisms of their interaction, economic viability, and a comparison of expected revenue generation from different types of microalgal consortia. The review mainly focuses on the therapeutic potentials of microalgae biomolecules and the optimization of different factors, such as the selection of consortium partners, inoculum ratio, cultivation types and modes, temperature, pH, light intensity, and photoperiod, that affect the biomass and biomolecule production of microalgal consortia which in future helps in enhancement in biomass and biomolecules production from microalgae and curing chronic diseases. The review discusses various types of microalgal consortia, aiding in selecting the most suitable consortia for future use. The review compares their biomass and biomolecule production with monoculture, outlining microalgal consortia's advantages, challenges, and prospects. Additionally, it discusses advanced artificial intelligence techniques that could assist in the future in the selection of compatible organisms and predict expected revenue generation.

Uranium mining effluents: What about the re-use of mining wastes to improve the bioproduction of industrially relevant bioactive compounds?

The shift towards a circular economy, where waste generation is minimized through waste re-use and the development of valorization strategies, is crucial for the establishment of a low carbon, sustainable, and resource-efficient economy. However, there is a lack of strategies for re-using and valorizing specific types of waste, particularly those containing naturally occurring radioactive materials (NORM), despite the prevalence of industrial activities that produce such waste due to their chemical and radiological hazards.Living organisms, including fungi, are valuable sources of bioactive compounds with various industrial applications. In this study, we assessed the growth and metabolic profile changes of three white rot fungi species in response to low concentrations of a uranium mine effluent containing NORM and metals to explore their potential for producing biotechnologically relevant bioactive compounds. The growth rate was assessed in three different culture media, with and without the uranium mine effluent (1% V/V)), and the metabolic profile was analyzed using FTIR-ATR spectroscopy.Results suggested an improvement in growth rates in media containing the uranium mine effluent, although not statistically significant. T. versicolor showed promise in terms of bioactive compound production. The production of droplets during growth experiments and significant metabolic changes, associated with the production of bioactive compounds like laccase, melanin, and oxalic acid, were observed in T. versicolor grown in mYEPDA with the uranium mine effluent. These findings present new research opportunities for utilizing waste to enhance the biotechnological production of industrially relevant bioactive compounds and promote the development of circular economy strategies for re-using and valorizing NORM-containing waste.

EXTRACTION AND GCMS ANALYSIS OF OIL FROM RED COCOYAM PEEL (colocasia esculenta)

Extraction of oil from red cocoyam peel has been carried out using the cold extraction method, with a reagent n-hexane as the extraction solvent The GC-MS was used to identify the components in the oil after extraction, the components that was found in the oil include, 1,3,5- trimethy benzene at a retention time of (2.844)min with a peak of 3.342%, n-hexadecanoic acid at a retention time of(7.250)min with a peak of 26.395%, 9,12-octadecadienoic acid at a retention time of (7.685)min with a peak of 2.036%, 1,1-dimethyl hexadecenoate at a retention time (7.794)min with a peak of 2.013%,9-octadecenoic acid with a retention time (8.023)min with a peak of 44.142%, 9,12,15-octadecatrienal at a retention time (8.154)min with a peak of 2.819%, Butyl 9,12-octadecadienoate at a retention time (8.555)min with a peak of 7.395%, squalene at a retention time of (10.151)min with a peak of 1.417%, Ergosta-5,22-dien-3-ol at a retention time of (15.879)min with a peak of 4.482%, 5-cholestene-3-ol,24-methyl at a retention time of (16.714) with a peak of 2.617%, 9,19-cyclolanost-24-en-3-ol at a retention time of (18.368) with a peak of 3.340%. and these components were found to be useful in pharmaceuticals, industries and cosmetics. This study contributes to the importance of sustainable utilization of agricultural byproducts and highlights the potential of red cocoyam peel as a valuable resource for the production of bioactive compounds with diverse industrial applications.

Cyclotriphosphazenes: Pre-harvest foliar applications improve antioxidant activity by increasing phenolic compounds in Lavandula angustifolia Mill.

The versatile chemical structures of cyclotriphosphazenes (CTPs) and their derivatives make them useful for various applications, including serving as plant nutrients to enhance the production of bioactive compounds. Therefore, the effects of 30 and 60 mg/L concentrations of CTPs (Compound 4 and 5) sprayed foliar at two different stages (pre-flowering stage and full-flowering stage) on total flavonoids and phenolic content, antioxidant activity, and accumulation of phenolics in lavender (Lavandula angustifolia Mill.) were investigated. Compounds 4 and 5 were purified by using column chromatography. The structures of the compounds were verified using mass, 1H, 31P nuclear magnetic resonance (NMR) spectroscopy, and Fourier-transform infrared (FT-IR) spectroscopy methods. The highest total phenolic content and antioxidant activity were achieved with Compound 5 (60 mg/L) treatment by using Folin-Ciocalteu and 2,2-diphenyl-1-picrylhydrazyl (DPPH) tests. The phenolic profile was determined by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Compound 4 treatment yielded a higher level of increase in total flavonoids, protocatechuic aldehyde, protocatechuic, caffeic acid, 4-OH benzoic, and salicylic acid, whereas Compound 5 treatment yielded a higher level of increase in vanillic, p-coumaric, ferulic, and rosmarinic acids. CTPs applied during the full-flowering stage resulted in significant increases, such as an 8.7-fold rise in protocatechuic acid, a 4.3-fold increase in protocatechuic aldehyde, and an 8.4-fold surge in caffeic acid. The caffeic acid was strongly and positively correlated with the 4-OH benzoic acid (,834**), vanillic acid (,955**), p-coumaric acid (,670**), and rosmarinic acid (,669**). The results showed that using a suitable cyclotriphosphazene compound(s) and selecting a suitable pre-harvest application time can significantly enhance and optimize the levels of phenolics.

The peels of sacred Lotus (Nelumbo nucifera) rhizomes suppress allergic reactions by inhibiting the A23187-induced degranulation in rat basophilic leukemia (RBL[sbnd]2H3) cells

We isolated ten compounds from methanolic extract of the peels of sacred lotus (Nelumbo nucifera) rhizomes which were identified as β-sitosterol linoleate 1, β-sitosterol 2, lupeol 3, stigmasterol 3-O-β-D-glucoside 4, oleanolic acid 5, betulinic acid 6, pinoresinol 7, 4-hydroxybenzoic acid 8, catechin 9 and gallocatechin 10. All of the isolated compounds from the peels of sacred lotus rhizomes are reported for the first time, and were investigated for their anti-allergic activity. We found that three of them, stigmasterol 3-O-β-D-glucoside 4, oleanolic acid 5 and pinoresinol 7, were capable of inhibiting A23187-induced degranulation in RBL-2H3 cells with IC50 values 0.18 ± 0.01 mM, 0.28 ± 0.06 mM, and 0.27 ± 0.01 mM, respectively. With an exception to 4, compounds 5 and 7 achieved the anti-allergic effect without affecting the cells viability even at higher concentrations with their selectivity indices (SI) being >5. By reducing A23187-induced degranulation, it is suggestive of a mechanism attenuation of Ca2+ elevation. Our findings suggest that, the peels of sacred lotus rhizomes would be beneficial for providing an inexpensive source for the production of bioactive compounds with anti-allergic effect.

Unveiling the Antioxidant and Antiulcer Potentials of Streptomyces

Streptomyces, known primarily for their prolific production of antibiotics, have recently garnered attention for their antioxidant properties. Antioxidants play a vital role in neutralizing harmful free radicals, thus protecting cells from oxidative damage and ultimately reducing the risk of various diseases. This review aims to comprehensively explore the antioxidant capabilities of Streptomyces spp., shedding light on their mechanisms of action, bioactive compounds involved, and potential applications in medicine and food industries. Streptomyces is a widely studied genus of bacteria that is known for its diverse metabolic capabilities and production of bioactive compounds. In recent years, there has been increasing interest in the antioxidant properties of Streptomyces and their potential applications in various industries, including pharmaceuticals, food, and cosmetics. Ulcerative diseases, particularly gastric and duodenal ulcers, pose a significant burden on public health worldwide. The search for effective therapeutic agents with anti-ulcer properties has led to the exploration of various natural sources, including Streptomyces. Streptomyces is a diverse genus of bacteria known for its ability to produce bioactive compounds with diverse biological activities. This review article aims to provide a comprehensive overview of the anti-ulcer properties of Streptomyces, the antioxidant properties of Streptomyces, including the mechanisms of action, bioactive compounds involved, and the potential therapeutic applications.

Comprehensive Nutritional and Functional Characterization of Novel Mycoprotein Derived from the Bioconversion of Durvillaea spp.

This study aimed, for the first time, to determine the nutritional composition, beta-glucan and ergosterol contents, phenolic compound composition, and biological and functional activities of a novel mycoprotein produced through a bioconversion process of Durvillaea spp., a brown seaweed. An untargeted metabolomics approach was employed to screen metabolites and annotate molecules with nutraceutical properties. Two products, each representing a distinct consortia of co-cultured fungi, named Myco 1 and Myco 2, were analysed in this study. These consortia demonstrated superior properties compared to those of Durvillaea spp., showing significant increases in total protein (~238%), amino acids (~219%), and β-D-glucans (~112%). The protein contains all essential amino acids, a low fatty acid content, and exhibits high antioxidant activity (21.5-25.5 µmol TE/g). Additionally, Myco 2 exhibited the highest anti-alpha-glucosidase activity (IC50 = 16.5 mg/mL), and Myco 1 exhibited notable anti-lipase activity (IC50 = 10.5 mg/mL). Among the 69 top differentially abundant metabolites screened, 8 nutraceutical compounds were present in relatively high concentrations among the identified mycoproteins. The proteins and polysaccharides in the mycoprotein may play a crucial role in the formation and stabilization of emulsions, identifying it as a potent bioemulsifier. In conclusion, the bioconversion of Durvillaea spp. results in a mycoprotein with high-quality protein, significant nutritional and functional value, and prebiotic and nutraceutical potential due to the production of unique bioactive compounds.

Effects of branched-chain amino acids on surfactin structure and antibacterial activity in Bacillus velezensis YA215.

Antibiotics are essential for combating pathogens; however, their misuse has led to increased resistance, necessitating the search for effective, low-toxicity alternatives. Surfactin, a cyclic lipopeptide with a C12-C17 β-hydroxy fatty acid chain, exhibits significant antibacterial activity and resists resistance, making it a research focus. Nonetheless, the effects of branched-chain amino acids (BCAAs) on surfactin's structure and activity are not well understood. This study examines the influence of BCAAs (L-valine, L-leucine, and L-isoleucine) on the lipopeptide (surfactin) produced by Bacillus velezensis YA215. Process optimization shows that adding 1g/L of L-Leu and L-Ile, and 0.5g/L of L-Val, maximized surfactin production to 18.59%, 19.23%, and 20.64%, respectively. Surfactin content peaked at 36h with L-Val and L-Ile, yielding 19.72% and 11.37%. In contrast, L-Leu addition peaked at 24h, yielding 11.33%. Notably, L-Val supplementation resulted in the highest relative surfactin content. Antimicrobial testing demonstrated that BCAAs significantly enhance the antibacterial effects of lipopeptides against Escherichia coli and Staphylococcus aureus, with Val showing the most pronounced effect. The addition of BCAAs notably altered the composition of surfactin fatty acid chains. Specifically, Val increased the proportions of iso C14 and iso C16 β-hydroxy fatty acids from 13.3% and 4.216-23.803% and 8.31%, respectively. Additionally, the amino acid composition at the 7th position of the peptide chain changed significantly, especially with Val addition, which increased the proportion of C14 [Val 7] surfactin by 3.29 times. These structural changes are likely associated with the enhanced antibacterial activity of surfactin. These findings provide valuable insights into the roles of BCAAs in microbial fermentation, underscoring their importance in metabolic engineering to enhance the production of bioactive compounds.

Plant-associated halotolerant bacteria improving growth of Vicia faba L. Mariout-2 under salinity conditions

In this comprehensive investigation, we successfully isolated and characterized 40 distinct plant-associated halotolerant bacteria strains obtained from three halophytic plant species: Tamarix nilotica, Suaeda pruinosa, and Arthrocnemum macrostachyum. From this diverse pool of isolates, we meticulously selected five exceptional plant-associated halotolerant bacteria strains through a judiciously designed seed biopriming experiment and then identified molecularly. Bacillus amyloliquefaciens DW6 was isolated from A. macrostachyum. Three bacteria (Providencia rettgeri DW3, Bacillus licheniformis DW4, and Salinicoccus sesuvii DW5) were isolated for the first time from T. nilotica, S. pruinosa and S. pruinosa, respectively. Paenalcaligenes suwonensis DW7 was isolated for the first time from A. macrostachyum. These plant-associated halotolerant bacteria exhibited growth-promoting activities, including phosphate solubilization, nitrogen fixation, and production of bioactive compounds, i.e., ammonia, phytohormones, hydrogen cyanide, siderophores, and exopolysaccharides. A controlled laboratory experiment was conducted to reduce the detrimental impact of soil salinity. Vicia faba seedlings were inoculated individually or in mixtures by the five most effective plant-associated halotolerant bacteria to reduce the impact of salt stress and improve growth parameters. The growth parameters were significantly reduced due to the salinity stress in the control samples, compared to the experimental ones. The unprecedented novelty of our findings is underscored by the demonstrable efficacy of co-inoculation with these five distinct bacterial types as a pioneering bio-approach for countering the deleterious effects of soil salinity on plant growth. This study thus presents a remarkable contribution to the field of plant science and offers a promising avenue for sustainable agriculture in saline environments.

Influence of metal and metal oxide nanoparticles on growth and total phenolic content accumulation of Anoectochilus roxburghii cultured in vitro

The application of metal nanoparticles in agriculture and related fields, especially in plant cell tissue culture has increased interest in recent years due to its potential benefits. This study used gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), copper nanoparticles (CuNPs) and magnetite nanoparticles (Fe3O4NPs) to evaluate their effect on the growth and total phenolic content (TPC) of Anoectochilus roxburghii. The results showed that Fe3O4 NPs were the most positively influenced metal nanoparticles in increasing biomass and TPC of A. roxburghii among metal nanoparticles tested. After 8 weeks of culture, the dry weight (DW) and TPC of the plants cultured on the medium containing 5 ppm Fe3O4NPs were 39.07 mg and 13.0 mg gallic acid respectively per g of dry weight (mg GAE/g DW). Meanwhile, on the medium without Fe3O4NPs, they were 30.47 mg and 6.71 mg GAE/g DW respectively. This study proposed an effective approach to improve the growth and accumulation of TPC in A. roxburghii. Moreover, it suggests the potential application of metal nanoparticles in plant tissue culture and the production of bioactive compounds.

Prophylactic Effect and Antiulcerogenic Potential of Probiotic Lactiplantibacillus plantarum E1K2R2 and its Exopolysaccharide Against Ibuprofen-Induced Acute Gastric Ulcer.

Lactiplantibacillus plantarum (Lpb. plantarum), as a safe probiotic microorganism, has been documented for its production of multiple bioactive compounds, such as exopolysaccharides (EPS), which have been used in the treatment of many gastrointestinal diseases, including gastric ulcers. The present study aims to investigate the prophylactic and antiulcerogenic effects of the potential probiotic Lbp. plantarum E1K2R2 and its EPS against ibuprofen-induced gastric ulcer. A gastric ulcer model was established by feeding fasted rats with ibuprofen at a single dose (200 mg/kg body weight). The Lpb. plantarum E1K2R2 (109 CFU), its EPS (200 mg/kg bw), and the anti-ulcer reference drug (omeprazole) (20 mg/kg bw) were separately used to feed rats for seven consecutive days before ibuprofen administration. The mechanisms were meticulously examined, focusing on the anti-secretory activity and mucus production as well as the anti-inflammatory and antioxidant activities. The findings revealed that the gastro-preventive effect of Lbp. plantarum E1K2R2 (88.43%) was higher than that of the EPS (66.26%) and close to that of omeprazole (89.87%). This effect was achieved through similar mechanisms, including regulation of the secretory activity, augmentation of mucus production, mitigation of inflammation, and enhancement of the gastric mucosa's antioxidant capacity. Moreover, it was found that Lbp. plantarum E1K2R2 and its EPS induce the activities of gastric antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and S-transferase (GST); enhance glutathione (GSH) content; and reduce mucosal nitric oxide (NO), myeloperoxidase (MPO), and malondialdehyde (MDA) levels. Furthermore, histopathological and hematological examinations confirmed that both pre-treatments could effectively maintain the structural integrity of the gastric mucosa and improve some hematological parameters, respectively. This implies that Lpb. plantarum E1K2R2 and its EPS possess the potential to counteract ibuprofen-associated gastric ulcers, leveraging a variety of protective mechanisms.

Micropropagation of Zuccagnia punctata, an argentine medicinal plant, by means of “in vitro” technology to promove its conservation and the sustainable production of bioactive compounds

Zuccagnia punctata Cav. (“jarilla poposa”) is a monotypic argentine native medicinal plant used by indigenous communities for the treatment of several pathologies. The pharmacological properties have been scientifically validated and its potential use in phytocosmetic and pharmaceutic industry as antiaged, hypoglycemic, anti-inflammatory, antitumoral, antioxidant, antibacterial and antimicotic has been previously demonstrated. However, the species has a low propagation rate in natural conditions and has been included in the preliminary red list of endangered plants in category 3. Therefore, it is necessary to develop methodologies leading to its conservation and propagation to achieve its sustainable use. The objective of this work is to perform a micropropagation protocol for Z. punctata species for the sustainable use and conservation of this species. Furthermore, the study evaluated also the impact of “in vitro” propagation on the content of bioactive compounds of ethanolic extracts obtained from Z. punctata plants obtained “in vitro” with collected wild plants. Seeds have been used as mother material. The seed germination to obtain explants were performed on Murashige and Skoog medium (MS) without plant growth regulators (PGRs) containing sucrose, agar, and ascorbic acid. The same medium was employed for the multiplication of shoots. “In vitro” rooting was achieved in liquid and semisolid medium, and a higher yield was obtained in the latter. The plants were transferred into commercial substrate and acclimatized in a greenhouse. The micropropagated plants (MP) had a high content of total phenolic compounds similar to those obtained from wild adult plants (WAP) collected in the Monte Desert. The flavonoid content of MP was higher than that of WAP. The main chalcones identified in WAP, 2′,4′ dihydroxychalcone (DHC) and 2′,4′-dihydroxy-3′-methoxychalcone (DHMC) were also present in the MP with a rate 1/1, and 1/3 in WAP. The extracts obtained from the MP showed antioxidant, antiinflammatory and antimicrobial activity, similar to WAP. The “in vitro” propagation and acclimatization of Z. punctata constitutes a fundamental tool to achieve large-scale multiplication of this species in the future and the sustainable production of bioactive compounds with commercial applications. Reimplantation in the natural habitat could prevent the loss of this medicinal genetic resource.

Harnessing the Potential of Harpin Proteins: Elicitation Strategies for Enhanced Secondary Metabolite Accumulation in Grapevine Callus Cultures

Grapes and grape products are rich in secondary metabolites such as phenolic compounds and anthocyanins, which have antioxidant properties. These compounds possess health-promoting attributes, including cardioprotective, antimicrobial, and anticancer effects. In recent years, biotechnological methods have been employed to produce high quantities and purity of secondary metabolites under in vitro conditions, aiming to elucidate their complex functions and optimize production methods. However, the potential effects of harpin proteins on the accumulation of secondary compounds in callus cultures have not been investigated thus far. Harpin proteins, encoded by the hrp gene clusters in Gram-negative phytopathogens, are known to trigger defense responses in various plant species by promoting the accumulation of secondary compounds. These findings suggest that harpin proteins may have the potential to enhance secondary metabolite accumulation in callus cultures. This study therefore investigated the potential of applying different concentrations of harpin protein (0, 0.1, 1, 10, and 100 ppm) to increase secondary metabolite production in calluses derived from petioles of the “Horoz Karası” grape cultivar. Our findings revealed that 1 and 10 ppm harpin treatments resulted in the highest anthocyanin accumulations, with 17.21 and 16.57 CV/g, respectively, representing 1.95- and 1.87-fold increases compared to control treatments, respectively. Total phenolic content peaked at 0.39 mg GAE g−1 FW with the 1 ppm harpin treatment, representing a 4.33-fold increase over the control. Total flavonol levels reached their highest levels at 0.027 mg CE g−1 FW with 1 and 10 ppm harpin concentrations, resulting in a 2.25-fold increase compared to the control. The highest averages for total flavonol content were recorded at 0.024 and 0.021 mg RE g−1 FW with 1 and 10 ppm harpin concentrations, respectively, representing 1.5- and 1.3-fold increases over the control. Principal component analysis (PCA) corroborated the results obtained from the heatmap analysis, indicating that harpin applications at 1 and 10 ppm were the most effective concentration range for maximizing secondary metabolite synthesis, while very low or high concentrations diminished these effects. These findings offered valuable insights for optimizing the production of high-value bioactive compounds, which can be utilized in various fields such as medicine, pharmaceuticals, food, and cosmetics. These results are expected to serve as a valuable reference for elucidating the mechanisms by which harpin proteins, rarely used in vitro, exert their effects on grapevine calluses, contributing to the literature in this domain.

Secondary metabolite profile of Streptomyces spp. changes when grown with the sub-lethal concentration of silver nanoparticles: possible implication in novel compound discovery.

The decline of new antibiotics and the emergence of multidrug resistance in pathogens necessitates a revisit of strategies used for lead compound discovery. This study proposes to induce the production of bioactive compounds with sub-lethal concentrations of silver nanoparticles (Ag-NPs). A total of Forty-two Actinobacteria isolates from four Saudi soil samples were grown with and without sub-lethal concentration of Ag-NPs (50µgml-1). The spent broth grown with Ag-NPs, or without Ag-NPs were screened for antimicrobial activity against four bacteria. Interestingly, out of 42 strains, broths of three strains grown with sub-lethal concentration of Ag-NPs exhibit antimicrobial activity against Staphylococcus aureus and Micrococcus luteus. Among these, two strains S4-4 and S4-21 identified as Streptomyces labedae and Streptomyces tirandamycinicus based on 16S rRNA gene sequence were selected for detailed study. The change in the secondary metabolites profile in the presence of Ag-NPs was evaluated using GC-MS and LC-MS analyses. Butanol extracts of spent broth grown with Ag-NPs exhibit strong antimicrobial activity against M. luteus and S. aureus. While the extracts of the controls with the same concentration of Ag-NPs do not show any activity. GC-analysis revealed a clear change in the secondary metabolite profile when grown with Ag-NPs. Similarly, the LC-MS patterns also differ significantly. Results of this study, strongly suggest that sub-lethal concentrations of Ag-NPs influence the production of secondary metabolites by Streptomyces. Besides, LC-MS results identified possible secondary metabolites, associated with oxidative stress and antimicrobial activities. This strategy can be used to possibly induce cryptic biosynthetic gene clusters for the discovery of new lead compounds.

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.