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Root exudates comprise a large variety of compounds released by plants into the rhizosphere, including low-molecular-weight primary metabolites (particularly saccharides, amino acids and organic acids) and secondary metabolites (phenolics, flavonoids and terpenoids). Changes in exudate composition could have impacts on the plant itself, on other plants, on soil properties (e.g. amount of soil organic matter), and on soil organisms. The effects of drought on the composition of root exudates, however, have been rarely studied. We used an ecometabolomics approach to identify the compounds in the exudates of Quercus ilex (holm oak) under an experimental drought gradient and subsequent recovery. Increasing drought stress strongly affected the composition of the exudate metabolome. Plant exudates under drought consisted mainly of secondary metabolites (71% of total metabolites) associated with plant responses to drought stress, whereas the metabolite composition under recovery shifted towards a dominance of primary metabolites (81% of total metabolites). These results strongly suggested that roots exude the most abundant root metabolites. The exudates were changed irreversibly by the lack of water under extreme drought conditions, and the plants could not recover.

Cannabis research has historically focused on the most prevalent cannabinoids. However, extracts with a broad spectrum of secondary metabolites may have increased efficacy and decreased adverse effects compared to cannabinoids in isolation. Cannabis’s complexity contributes to the length and breadth of its historical usage, including the individual application of the leaves, stem barks, and roots, for which modern research has not fully developed its therapeutic potential. This study is the first attempt to profile secondary metabolites groups in individual plant parts comprehensively. We profiled 14 cannabinoids, 47 terpenoids (29 monoterpenoids, 15 sesquiterpenoids, and 3 triterpenoids), 3 sterols, and 7 flavonoids in cannabis flowers, leaves, stem barks, and roots in three chemovars available. Cannabis inflorescence was characterized by cannabinoids (15.77–20.37%), terpenoids (1.28–2.14%), and flavonoids (0.07–0.14%); the leaf by cannabinoids (1.10–2.10%), terpenoids (0.13–0.28%), and flavonoids (0.34–0.44%); stem barks by sterols (0.07–0.08%) and triterpenoids (0.05–0.15%); roots by sterols (0.06–0.09%) and triterpenoids (0.13–0.24%). This comprehensive profile of bioactive compounds can form a baseline of reference values useful for research and clinical studies to understand the “entourage effect” of cannabis as a whole, and also to rediscover therapeutic potential for each part of cannabis from their traditional use by applying modern scientific methodologies.

Endophytic fungi may be a potent source of bioactive compounds and have a vast repertoire of diverse metabolites. One source of endophytic fungi host plants is a medicinal plant such as Brotowali or Tinospora crispa. Research corresponding to the antibacterial activity of endophytic fungi extracts isolated from T.crispa taken from several regions in West Java has never been reported yet. While antibacterial methods to evaluate their activity as well as to identify the chemical compounds is a TLC-bioautography assay. This research is aimed to investigate the components of endophytic fungal extracts and their antibacterial activity using the TLC-bioautography assay method. In this study, eighty isolates of endophytic fungi have been successfully isolated from plant tissues of T.crispa from several regions in West Java. Antibacterial activity by using TLC (dot-blot) plates revealed that the fungal extracts could inhibit S. aureus (77 extracts) and E. coli (35 extracts) with inhibition zones ranging from 8-30 mm. The endophytic fungi extracts that showed potent antibacterial activity against Gram-positive bacteria (S.aureus) were sixteen extracts, while nine extracts have good inhibition activity against Gram-negative bacteria (E.coli). Among the fungal extracts that have excellent ability against both Gram-positive and negative was namely TcBt1Bd-10 extract. Based on metabolites analysis using the TLC method, the possibility of the chemical compounds that played a role in antibacterial activity of the extracts, including phenolics, flavonoids, alkaloids, and terpenoids.

Secondary organic aerosol contributes to the atmospheric particle burden with implications for air quality and climate. Biogenic volatile organic compounds such as terpenoids emitted from plants are important secondary organic aerosol precursors with isoprene dominating the emissions of biogenic volatile organic compounds globally. However, the particle mass from isoprene oxidation is generally modest compared to that of other terpenoids. Here we show that isoprene, carbon monoxide and methane can each suppress the instantaneous mass and the overall mass yield derived from monoterpenes in mixtures of atmospheric vapours. We find that isoprene ‘scavenges’ hydroxyl radicals, preventing their reaction with monoterpenes, and the resulting isoprene peroxy radicals scavenge highly oxygenated monoterpene products. These effects reduce the yield of low-volatility products that would otherwise form secondary organic aerosol. Global model calculations indicate that oxidant and product scavenging can operate effectively in the real atmosphere. Thus highly reactive compounds (such as isoprene) that produce a modest amount of aerosol are not necessarily net producers of secondary organic particle mass and their oxidation in mixtures of atmospheric vapours can suppress both particle number and mass of secondary organic aerosol. We suggest that formation mechanisms of secondary organic aerosol in the atmosphere need to be considered more realistically, accounting for mechanistic interactions between the products of oxidizing precursor molecules (as is recognized to be necessary when modelling ozone production). Adding reactive gases such as isoprene to mixtures lowers the production of secondary organic aerosol in the atmosphere, thus reducing the atmospheric particulate burden, with implications for human health and climate.

Advanced biofuels produced by microorganisms have similar properties to petroleum-based fuels, and can 'drop in' to the existing transportation infrastructure. However, producing these biofuels in yields high enough to be useful requires the engineering of the microorganism's metabolism. Such engineering is not based on just one specific feedstock or host organism. Data-driven and synthetic-biology approaches can be used to optimize both the host and pathways to maximize fuel production. Despite some success, challenges still need to be met to move advanced biofuels towards commercialization, and to compete with more conventional fuels.

This review covers general information about the eco-friendly process for the synthesis of silver nanoparticles (AgNP) and gold nanoparticles (AuNP) and focuses on mechanism of the antibacterial activity of AgNPs and the anticancer activity of AuNPs. Biomolecules in the plant extract are involved in reduction of metal ions to nanoparticle in a one-step and eco-friendly synthesis process. Natural plant extracts contain wide range of metabolites including carbohydrates, alkaloids, terpenoids, phenolic compounds, and enzymes. A variety of plant species and plant parts have been successfully extracted and utilized for AgNP and AuNP syntheses. Green-synthesized nanoparticles eliminate the need for a stabilizing and capping agent and show shape and size-dependent biological activities. Here, we describe some of the plant extracts involved in nanoparticle synthesis, characterization methods, and biological applications. Nanoparticles are important in the field of pharmaceuticals for their strong antibacterial and anticancer activity. Considering the importance and uniqueness of this concept, the synthesis, characterization, and application of AgNPs and AuNPs are discussed in this review.

More than 70,000 different terpenoid structures are known so far; many of them offer highly interesting applications as pharmaceuticals, flavors and fragrances, or biofuels. Extraction of these compounds from their natural sources or chemical synthesis is—in many cases—technically challenging with low or moderate yields while wasting valuable resources. Microbial production of terpenoids offers a sustainable and environment-friendly alternative starting from simple carbon sources and, frequently, safeguards high product specificity. Here, we provide an overview on employing recombinant bacteria and yeasts for heterologous de novo production of terpenoids. Currently, Escherichia coli and Saccharomyces cerevisiae are the two best-established production hosts for terpenoids. An increasing number of studies have been successful in engineering alternative microorganisms for terpenoid biosynthesis, which we intend to highlight in this review. Moreover, we discuss the specific engineering challenges as well as recent advances for microbial production of different classes of terpenoids. Rationalizing the current stages of development for different terpenoid production hosts as well as future prospects shall provide a valuable decision basis for the selection and engineering of the cell factory(ies) for industrial production of terpenoid target molecules.

The biosynthesis of natural products by heterologous expression of biosynthetic pathways in amenable production strains enables biotechnological access to a variety of valuable compounds by conversion of renewable resources. Pseudomonas putida has emerged as a microbial laboratory work horse, with elaborated techniques for cultivation and genetic manipulation available. Beyond that, this bacterium offers several particular advantages with regard to natural product biosynthesis, notably a versatile intrinsic metabolism with diverse enzymatic capacities as well as an outstanding tolerance to xenobiotics. Therefore, it has been applied for recombinant biosynthesis of several valuable natural products. This review provides an overview of applications of P. putida as a host organism for the recombinant biosynthesis of such natural products, including rhamnolipids, terpenoids, polyketides and non-ribosomal peptides, and other amino acid-derived compounds. The focus is on de novo natural product synthesis from intrinsic building blocks by means of heterologous gene expression and strain engineering. Finally, the future potential of the bacterium as a chassis organism for synthetic microbiology is pointed out.

Isoprenoids, often called terpenoids, are the most abundant and highly diverse family of natural organic compounds. In plants, they play a distinct role in the form of photosynthetic pigments, hormones, electron carrier, structural components of membrane, and defence. Many isoprenoids have useful applications in the pharmaceutical, nutraceutical, and chemical industries. They are synthesized by various isoprenoid synthase enzymes by several consecutive steps. Recent advancement in metabolic engineering and synthetic biology has enabled the production of these isoprenoids in the heterologous host systems like Escherichia coli and Saccharomyces cerevisiae. Both heterologous systems have been engineered for large-scale production of value-added isoprenoids. This review article will provide the detailed description of various approaches used for engineering of methyl-d-erythritol-4-phosphate (MEP) and mevalonate (MVA) pathway for synthesizing isoprene units (C5) and ultimate production of diverse isoprenoids. The review particularly highlighted the efforts taken for the production of C5–C20 isoprenoids by metabolic engineering techniques in E. coli and S. cerevisiae over a decade. The challenges and strategies are also discussed in detail for scale-up and engineering of isoprenoids in the heterologous host systems.Key points• Isoprenoids are beneficial and valuable natural products.• E. coli and S. cerevisiae are the promising host for isoprenoid biosynthesis.• Emerging techniques in synthetic biology enabled the improved production.• Need to expand the catalogue and scale-up of un-engineered isoprenoids.

Sandalwood oil is a valuable resource derived from Santalum album. It has antibacterial, cosmetic, and sedative effects. [alpha]-Santalene is the precursor of [alpha]-santalol, the main component of sandalwood oil. Yarrowia lipolytica is an oleaginous yeast, which has been metabolically engineered to produce valuable compounds such as terpenoids and biofuel. This study presents a method for the heterologous synthesis of [alpha]-santalene by Y. lipolytica. Using Y. lipolytica ATCC 201249, a codon-optimized plant-origin [alpha]-santalene synthase (STS) was integrated into the genome, and a yield of 5.19 mg/L [alpha]-santalene was obtained after fermentation. Upstream genes in the MVA pathway (ERG8, ERG10, ERG12, ERG13, ERG19, ERG20, HMG1, and tHMG1) were overexpressed, and we found that the key genes ERG8, HMG1, and tHMG1 can increase the supply of FPP and the yield of [alpha]-santalene. ERG8 and HMG1 were overexpressed in multiple-copy formats, and the plasmid pERG8HMG1 and ERG8-HMG1 expression modules were optimized as single-copy and multiple-copy formats, respectively. The overexpression of single-copy plasmid pERG8HMG1 led to [alpha]-santalene yield of 13.31 mg/L. The optimal feeding strategy was determined by initial carbon source concentration optimizations and five feeding methods. Using 50 g/L glucose as the initial carbon source, maintaining the carbon source concentration at 5-20 g/L during the feeding process is most conducive to increased production. These results were verified in a 5-L fermenter by batch and fed-batch fermentation. The OD of fed-batch fermentation broth reached 79.09, and the production of [alpha]-santalene reached 27.92 mg/L; 5.38 times of the initial yield, without by-products farnesol and trans-[alpha]-bergamotene.