Microbial Extracts Research Articles

Comparative analysis of assembly algorithms to optimize biosynthetic gene cluster identification in novel marine actinomycete genomes

Many marine sponges harbor dense communities of microbes that aid in the chemical defense of these nonmotile hosts. Metabolites that comprise this chemical arsenal can have pharmaceutically-relevant activities such as antibacterial, antiviral, antifungal and anticancer properties. Previous investigation of the Caribbean giant barrel sponge Xestospongia muta revealed a microbial community including novel Actinobacteria, a phylum well known for its production of antibiotic compounds. This novel assemblage was investigated for its ability to produce compounds that inhibit M. tuberculosis by using a bioinformatics approach. Microbial extracts were tested for their ability to inhibit growth of M. tb and genomes of the 11 strains that showed anti-M. tb activity including Micrococcus (n=2), Micromonospora (n=4), Streptomyces (n=3), and Brevibacterium spp. (n=2) were sequenced by using Illumina MiSeq. Three assembly algorithms/pipelines (SPAdes, A5-miseq and Shovill) were compared for their ability to construct contigs with minimal gaps to maximize the probability of identifying complete biosynthetic gene clusters (BGCs) present in the genomes. Although A5-miseq and Shovill usually assembled raw reads into the fewest contigs, after necessary post-assembly filtering, SPAdes generally produced the most complete genomes with the fewest contigs. This study revealed the strengths and weaknesses of the different assemblers based on their ease of use and ability to be manipulated based on output format. None of the assembly methods handle contamination well and high-quality DNA is a prerequisite. BGCs of compounds with known anti-TB activity were identified in all Micromonospora and Streptomyces strains (genomes > 5 Mb), while no such BGCs were identified in Micrococcus or Brevibacterium strains (genomes < 5 Mb). The majority of the putative BGCs identified were located on contig edges, emphasizing the inability of short-read assemblers to resolve repeat regions and supporting the need for long-read sequencing to fully resolve BGCs.

The role of soil communities on the germination of a pioneer tree species in the Atlantic rainforest

Climate change has been modifying precipitation and temperature in many regions of the world, prompting changes in plant communities. It also affects soil microbial communities, indirectly influencing plant species distribution through plant-soil feedbacks. Here we report an experiment designed to test seed germination responses to global change, addressed through the interaction between increased temperature and soil microbial communities in a tree species in the Atlantic rainforest, a global biodiversity hotspot. Our objective was to test plant-soil feedbacks in an early colonizer tree species, Schizolobium parahyba, and their interaction with warming. We assessed the role of increased air temperature and soil microbiota in controlling seed germination as a function of distance to mother tree. Higher germination percentages were recorded with extracts of soil microbial communities from the edge of the canopy than with microbial extracts obtained closer to the trunk. These manipulations evidenced that soil microbiota influenced seed germination, being responsible for Janzen–Connell effects. Warming produced major changes in microbial composition but the effect on germination was unclear. Our results may help understand species distribution and coexistence in secondary patches of Atlantic rainforest under warmer conditions, and may contribute to the design of successful restoration programs.

Physiological regulation for enhancing biosynthesis of biofilm-inhibiting secondary metabolites in Streptomyces cellulosae.

Although the production of the secondary metabolite is frequently restricted, methods to regulate and optimize their synthesis are extremely beneficial. The current study proposes to enhance the production of antibiofilm metabolite in Streptomyces cellulosae (S. cellulosae). It was isolated from soil by growing on Gause'smedia and identified by colony morphology and genomic sequencing of 16S rDNA. Antibacterial and antibiofilm activities of the isolates were screened against a series of pathogenic bacteria by agar plug diffusion and 96 well microtiter plate methods, respectively. Physiological regulation of the bacterial bioactivity against biofilm formation was monitored under different cultural conditions. The isolated Streptomyces sequence analysis of the 16S rDNA was 100% identical to the sequence of S. cellulosae strain NBRC 13027. Physical (temperature and pH) and chemical (carbon, nitrogen, and minerals) culture medium factors have shown variable impacts on the growth and bioactive substances of S. cellulosae. Moreover, results of simple linear regression and correlation suggested that most of the physiological regulations with the highest response (r2= 0.85-0.99; p<0.01) and linearly (r= 0.88-0.99; p<0.01) were correlated between microbial biomass and crude extract. Lastly, under different culture growth conditions, biofilm inhibition was tested against Pseudomonas aeruginosa (P. aeruginosa). The physiological regulation results exhibited that 1 μg/mL of the extract was the most efficient concentration against biofilm formation in P. aeruginosa while 3 μg/mL is an effective bactericidal dose against P. aeruginosa. We concluded that S. cellulosae can produce antibacterial and antibiofilm metabolites. Physiological regulation is considered a powerful tool that can be used for increasing the biosynthesis of the active metabolites and biomass.

Curvicollide D Isolated from the Fungus Amesia sp. Kills African Trypanosomes by Inhibiting Transcription.

Sleeping sickness or African trypanosomiasis is a serious health concern with an added socio-economic impact in sub-Saharan Africa due to direct infection in both humans and their domestic livestock. There is no vaccine available against African trypanosomes and its treatment relies only on chemotherapy. Although the current drugs are effective, most of them are far from the modern concept of a drug in terms of toxicity, specificity and therapeutic regime. In a search for new molecules with trypanocidal activity, a high throughput screening of 2000 microbial extracts was performed. Fractionation of one of these extracts, belonging to a culture of the fungus Amesia sp., yielded a new member of the curvicollide family that has been designated as curvicollide D. The new compound showed an inhibitory concentration 50 (IC50) 16-fold lower in Trypanosoma brucei than in human cells. Moreover, it induced cell cycle arrest and disruption of the nucleolar structure. Finally, we showed that curvicollide D binds to DNA and inhibits transcription in African trypanosomes, resulting in cell death. These results constitute the first report on the activity and mode of action of a member of the curvicollide family in T. brucei.

Bioactive Metabolites of Nodule Associated Microbes for Enhanced Drought Tolerance and Biocontrol Control Activity in Horsegram

In the present study, the potential bioactive compounds detected in the ethyl acetate microbial extract of root nodules of horsegram were determined using the gas chromatography-mass spectroscopy (GC-MS). The bioactive metabolites of nodule associated microbes (NAM) revealed the existence of several soluble metabolites which includes phthalic acid, butyl hex-3-yl ester, 2,4-Di-tert-butylphenol,Dodecyl acrylate, pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro, 1-Nonadecene, octadecane, 1,2-Benzenedicarboxylic acid, bis(2-methylpropyl) ester, hexadecanoic acid, methyl ester, dibutyl phthalate, diisooctyl phthalate, 1-docosene, heptadecane, 9-hexyl, pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(phenylmethyl), n-Tetracosanol-1, ergotaman-3',6',18-trione, 9,10-dihydro-12'-hydroxy-2'-methyl-5'(phenylmethyl)-, (5'à,10à), eicosanal, ethanol, 2-(9-octadecenyloxy), E-15-heptadecenal, octatriacontyl pentafluoropropionate, etc.,. Endophytic bacteria produces bioactive substances that provides resistance against phytopathogens as well as nutrient solubilization during prolonged drought periods in order to overcome biotic and abiotic stresses. Several antibacterial, antifungal, antiviral and antioxidant properties were brought under spotlight to realise the beneficial aspects of nodule associated microbes of horsegram. Understanding the roles of metabolites would enrich the crop growth under stressed environment by promoting the eco-friendly agriculture practices.

Exploring the Diversity and Antibacterial Potentiality of Cultivable Actinobacteria from the Soil of the Saxaul Forest in Southern Gobi Desert in Mongolia.

Saxaul (Haloxylon ammodendron) is the most widespread plant community in the Gobi Desert in Mongolia, which plays important roles in wind control, sand fixation and water conservation. Investigations of soil-derived actinobacteria inhabiting in the saxaul forest in Gobi Desert in Mongolia have been scarce. In this study, biodiversity of culturable actinobacteria isolated from soil of the saxaul forest in Southern Gobi Aimak (Southern Gobi Province) of Mongolia was characterized and their potential to produce compounds with antibacterial activities was assessed. A total of 172 actinobacterial strains were recovered by culture-based approaches and were phylogenetically affiliated into 22 genera in 13 families of seven orders. Forty-nine actinobacterial isolates were selected to evaluate the antibacterial activities and their underlying mechanism of action was screened by means of a dual-fluorescent reporter assay (pDualrep2). Twenty-three isolates exhibited antagonistic activity against at least one of the tested pathogens, of which two Streptomyces strains can attenuate protein translation by ribosome stalling. Combinational strategies based on modern metabolomics, including bioassay-guided thin-layer chromatography (TLC), UPLC-QTOF-MS/MS based structural annotation and enhanced molecular networking successfully annotated chloramphenicol, althiomycin and granaticin and their derivatives as the antibacterial compounds from extracts in three Streptomyces strains, respectively. This work demonstrates that UPLC-MS/MS-based structural identification and enhanced molecular networking are effective strategies to rapidly illuminate the bioactive chemicals in the microbial extracts. Meanwhile, our results show that the saxaul forest in Mongolia Gobi Desert is a prospective source for discovering novel actinobacteria and biologically active compounds.

Boron NMR as a Method to Screen Natural Product Libraries for B-Containing Compounds.

Natural products are biologically relevant metabolites exploited for biomedicine and biotechnology. The frequent reisolation of known natural products questions whether existing discovery models are still capable of identifying novel compounds. As innovative NMR-based screening techniques can help overcome these challenges, we applied a phase cycling composite pulse sequence to 11B NMR experiments to enhance their sensitivity to screen libraries for novel boron-containing molecules. Aplasmomycin and autoinducer-2 were detected in crude and enhanced microbial fractions, via their boron signals, as proof of concept. Subsequently, a screen of 21 crude plant and 50 crude marine microbial extracts were chosen at random and analyzed with the optimized 11B experiment for feasibility as a high throughput discovery method. Eight of the plant samples and 13 of the microbial samples were identified as boron-containing, suggesting that there is a higher presence of boron metabolites available from natural sources than previously known due to a lack of appropriate discovery methods. As a result, we believe that this optimized 11B NMR experiment can serve as a robust method for quick and facile discovery of novel boron-containing metabolites from a variety of natural sources.

Microbial community from species rich meadow supports plant specialists during meadow restoration

Abstract Soil properties and soil microbial communities can greatly affect plant communities, especially in disturbed ecosystems. However, their relative contribution to the final effect on plants has rarely been assessed. We manipulated the soil microbial community in microcosms by inoculating sterilized soils originating from preserved species‐rich meadow and a restored meadow with a high and low diversity of microbial inoculum (manipulated by the dilution of microbial community extract) from those soils in full factorial manner, yielding eight treatments (2 soil origins × 2 inoculum sources × 2 levels of inoculum diversity). In general, the biomass of plant meadow specialists (Filipendula vulgaris, Phleum phleoides, and Prunella grandiflora) was greater with the preserved meadow inoculum than with the restored meadow inoculum but tended to be greater in the restored meadow soil than in the preserved meadow soil. Two meadow generalists (Festuca rubra and Centaurea jacea) were not significantly affected by soil origin, inoculum source, or inoculum diversity, but the third generalist Plantago media produced greater biomass in the preserved meadow soil than in the restored meadow soil. Total above‐ground biomass was not affected by the treatments, but total below‐ground biomass was greater with microbial inoculum from the preserved meadow than from the restored meadow, and this increase was greater in the restored meadow soil than in the preserved meadow soil. Our results indicate strong responses of the preserved meadow specialists to the soil microbial community, which may explain why they are rare in the meadows that were restored following agricultural use. Read the free Plain Language Summary for this article on the Journal blog.

A novel and affordable bioaugmentation strategy with microbial extracts to accelerate the biodegradation of emerging contaminants in different media

This study describes a new bioaugmentation alternative based on the application of aqueous aerated extracts from a biomixture acclimated with ibuprofen, diclofenac and triclosan. This bioaugmentation strategy was assayed in biopurification systems (BPS) and in contaminated aqueous solutions to accelerate the removal of these emerging contaminants. Sterilized extracts or extracts from the initial uncontaminated biomixture were used as controls. In BPS, the dissipation of 90% of diclofenac and triclosan required, respectively, 60 and 108 days less than in the controls. The metabolite methyl-triclosan was determined at levels 12 times lower than in controls. In the bioaugmented solutions, ibuprofen was almost completely eliminated (99%) in 21 days and its hydroxylated metabolites were also determined to be at lower levels than in the controls. The plasmidome of acclimated biomixtures and its extract appeared to maintain certain types of plasmids but degradation related genes became less evident. Several dominant OTUs found in the extract identified as Flavobacterium and Fluviicola of the phylum Bacteroidetes, Thermomicrobia (phylum Chloroflexi) and Nonomuraea (phylum Actinobacteria), may be responsible for the enhanced dissipation of these contaminants. This bioaugmentation strategy represents an advantageous tool to facilitate in situ bioaugmentation.

In Vitro Study on Actinomycetes Extracts Against The Stem Bleeding Disease of Coconut

Several compounds produced by Actinomycetes group of bacteria have proven potential in inhibiting plant pathogenic fungi. In the present study, two microbial ethyl acetate extracts from Streptomyces were tested for their antifungal properties against Thielaviopsis paradoxa, the causal organism of stem bleeding disease in coconut. The cultural filtrates of 2 strains of Streptomyces (AFL-1 and AFL-2) were extracted with Ethyl acetrate. The resulting ethyl acetate extract of AFL-1 showed complete in-vitro inhibition of fungal growth at relatively low concentrations (0.25%) while Ethyl ecetate extract of AFL-2 needed higher concentrations (over 0.5%) to eliminate pathogen growth. This finding indicate their potential and further exploitation as biopesticides for the control of deadly pathogen T. paradoxa.

Afidopyropen, a novel insecticide originating from microbial secondary extracts

Afidopyropen, a novel insecticide, is a derivative of pyripyropene A, which is produced by the filamentous fungus Penicillium coprobium. Afidopyropen has strong insecticidal activity against aphids and is currently used as a control agent of sucking pests worldwide. In this study, we summarized the biological properties and field efficacies of its derivatives against agricultural pests using official field trials conducted in Japan. Afidopyropen showed good residual efficacies against a variety of aphids, whiteflies and other sucking pests under field conditions. Furthermore, toxicological studies revealed its safety profiles against nontarget organisms, such as the honeybee, natural enemies and other beneficial insects, as well as mammals. Thus, afidopyropen is a next-generation agrochemical for crop protection that has a low environmental impact.

CACONET: a novel classification framework for microbial correlation networks.

MotivationExisting microbiome-based disease prediction relies on the ability of machine learning methods to differentiate disease from healthy subjects based on the observed taxa abundance across samples. Despite numerous microbes have been implicated as potential biomarkers, challenges remain due to not only the statistical nature of microbiome data but also the lack of understanding of microbial interactions which can be indicative of the disease.ResultsWe propose CACONET (classification of Compositional-Aware COrrelation NETworks), a computational framework that learns to classify microbial correlation networks and extracts potential signature interactions, taking as input taxa relative abundance across samples and their health status. By using Bayesian compositional-aware correlation inference, a collection of posterior correlation networks can be drawn and used for graph-level classification, thus incorporating uncertainty in the estimates. CACONET then employs a deep learning approach for graph classification, achieving excellent performance metrics by exploiting the correlation structure. We test the framework on both simulated data and a large real-world dataset pertaining to microbiome samples of colorectal cancer (CRC) and healthy subjects, and identify potential network substructure characteristic of CRC microbiota. CACONET is customizable and can be adapted to further improve its utility.Availability and implementationCACONET is available at https://github.com/yuanwxu/corr-net-classify.Supplementary information Supplementary data are available at Bioinformatics online.

Green approaches for the synthesis of metal and metal oxide nanoparticles using microbial and plant extracts.

Green synthesis approaches are gaining significance as promising routes for the sustainable preparation of nanoparticles, offering reduced toxicity towards living organisms and the environment. Nanomaterials produced by green synthesis approaches can offer additional benefits, including reduced energy inputs and lower production costs than traditional synthesis, which bodes well for commercial-scale production. The biomolecules and phytochemicals extracted from microbes and plants, respectively, are active compounds that function as reducing and stabilizing agents for the green synthesis of nanoparticles. Microorganisms, such as bacteria, yeasts, fungi, and algae, have been used in nanomaterials' biological synthesis for some time. Furthermore, the use of plants or plant extracts for metal and metal-based hybrid nanoparticle synthesis represents a novel green synthesis approach that has attracted significant research interest. This review discusses various biosynthesis approaches via microbes and plants for the green preparation of metal and metal oxide nanoparticles and provides insights into the molecular aspects of the synthesis mechanisms and biomedical applications. The use of agriculture waste as a potential bioresource for nanoparticle synthesis and biomedical applications of biosynthesized nanoparticles is also discussed.

A Novel and Affordable Bioaugmentation Strategy with Microbial Extracts to Accelerate the Biodegradation of Emerging Contaminants in Different Media

A Novel and Affordable Bioaugmentation Strategy with Microbial Extracts to Accelerate the Biodegradation of Emerging Contaminants in Different Media

Novel Alkaloids from Marine Actinobacteria: Discovery and Characterization.

The marine environment is an excellent resource for natural products with therapeutic potential. Its microbial inhabitants, often associated with other marine organisms, are specialized in the synthesis of bioactive secondary metabolites. Similar to their terrestrial counterparts, marine Actinobacteria are a prevalent source of these natural products. Here, we discuss 77 newly discovered alkaloids produced by such marine Actinobacteria between 2017 and mid-2021, as well as the strategies employed in their elucidation. While 12 different classes of alkaloids were unraveled, indoles, diketopiperazines, glutarimides, indolizidines, and pyrroles were most dominant. Discoveries were mainly based on experimental approaches where microbial extracts were analyzed in relation to novel compounds. Although such experimental procedures have proven useful in the past, the methodologies need adaptations to limit the chance of compound rediscovery. On the other hand, genome mining provides a different angle for natural product discovery. While the technology is still relatively young compared to experimental screening, significant improvement has been made in recent years. Together with synthetic biology tools, both genome mining and extract screening provide excellent opportunities for continued drug discovery from marine Actinobacteria.

Exploring natural microbial resources for the discovery of anti-malarial compounds.

Microorganisms in nature are highly diverse biological resources, which can be explored for drug discovery. Some countries including Brazil, Columbia, Indonesia, China, and Mexico, which are blessed with geographical uniqueness with diverse climates and display remarkable megabiodiversity, potentially provide microorganismal resources for such exploitation. In this review, as an example of drug discovery campaigns against tropical parasitic diseases utilizing microorganisms from such a megabiodiversity country, we summarize our past and on-going activities toward discovery of new antimalarials. The program was held in a bilateral collaboration between multiple Indonesian and Japanese research groups. In order to develop a new platform of drug discovery utilizing Indonesian bioresources under an international collaborative scheme, we aimed at: 1) establishment of an Indonesian microbial depository, 2) development of robust enzyme-based and cell-based screening systems, and 3) technology transfer necessary for screening, purification, and identification of antimalarial compounds from microbial culture broths. We collected, characterized, and deposited Indonesian microbes. We morphologically and genetically characterized fungi and actinomycetes strains isolated from 5 different locations representing 3 Indonesian geographical areas, and validated genetic diversity of microbes. Enzyme-based screening was developed against two validated mitochondrial enzymes from Plasmodium falciparum, dihydroorotate dehydrogenase and malate:quinone oxidoreductase, while cell-based proliferation assay was developed using the erythrocytic stage parasite of 3D7 strain. More than 17 thousands microbial culture extracts were subjected to the enzyme- and cell-based screening. Representative anti-malarial compounds discovered in this campaign are discussed, including a few isolated compounds that have been identified for the first time as anti-malarial compounds. Our antimalarial discovery campaign validated the Indonesian microbial library as a powerful resource for drug discovery. We also discuss critical needs for selection criteria for hits at each stage of screening and hit deconvolution such as preliminary extraction test for the initial profiling of the active compounds and dereplication techniques to minimize repetitive discovery of known compounds.

ASSESSMENT OF AIRBORNE FUNGAL SPORES IN INDOOR ENVIRONMENT OF LIBRARIES IN NNAMDI AZIKIWE UNIVERSITY

Background: Polluted indoor environments pose health challenges such as allergy, infections, and toxicity. Most indoor air pollution comes from hazardous non-biological and biological agents. Due to the nature of the indoor environment of libraries, it is prone to colonization by fungal species. Method: Three sampling sites were used for the study and they include Festus Aghagbo Nwako Library, Main campus Awka, Medical Library, Nnewi Campus and Library Complex, Agulu campus. A total of 100 air samples were analyzed Using the Zefon A6 Single-stage microbial air sampler and Malt Extract Agar supplemented with 0.05mg/ml of chloramphenicol while 16 nasal swabs were collected from the staff present using sterile swab sticks. The mould isolates were identified using the slide culture technique while the yeast isolates were subjected to candida chrom agar and integral yeast plus identification. Antifungal susceptibility was performed using the integral yeast plus system and the agar well diffusion technique. Results: Out of the 100 air samples, a total of 625 fungal isolates were identified of which C.lunata 201 (32.16%) was the most predominant, while P. marneffi, P. expansum, A. restrictus, A. infectoria and R. rubra 1(0.16%) occurred the least. All significant at (p≤0.01). A total of 7 fungal spores were isolated from the 16 nasal swabs and appeared thus in descending order of frequency: P. notatum, 3 (42.85%), A. niger, C. lunata, C. albicans and F. aqueductum, 1(14.3%). Antifungal Susceptibility of the 28 yeast isolates indicated that C. famata, C. laurentii and C. luteolus, were all susceptible to commonly used antifungals in the integral yeast plus system with a 100% susceptibility value, while the mould isolates showed relatively moderate susceptibility to selected antifungals. Conclusion: The organisms isolated are well known to be pathogenic especially to immunocompromised individuals. Their presence in the indoor environment of libraries serves as a risk factor to both the library staff and visitors. Adequate precautionary measures and occasional environmental surveillance need to be inculcated in order to reduce the number of fungi in the indoor environment of these libraries.

Traditional in vitro strategies for sustainable production of bioactive compounds and manipulation of metabolomic profile in medicinal, aromatic and ornamental plants.

Precursor feeding, elicitation and culture medium parameters are traditional in vitro strategies to enhance bioactive compounds of medicinal, aromatic, and ornamental plants (MAOPs). Machine learning can help researchers find the best combination of these strategies to increase the secondary metabolites content of MAOPs. Many requirements for human life, from food, pharmaceuticals and cosmetics to clothes, fuel and building materials depend on plant-derived natural products. Essential oils, methanolic and ethanolic extracts of in vitro undifferentiated callus and organogenic cultures of medicinal, aromatic, and ornamental plants (MAOPs) contain bioactive compounds that have several applications for various industries, including food and pharmaceutical. In vitro culture systems provide opportunities to manipulate the metabolomic profile of MAOPs. Precursors feeding, elicitation and culture media optimization are the traditional strategies to enhance in vitro accumulation of favorable bioactive compounds. The stimulation of plant defense mechanisms through biotic and abiotic elicitors is a simple way to increase the production of secondary metabolites in different in vitro culture systems. Different elicitors have been applied to stimulate defense machinery and change the metabolomic profile of MAOPs in in vitro cultures. Plant growth regulators (PGRs), stress hormones, chitosan, microbial extracts and physical stresses are the most applied elicitors in this regard. Many other chemical tolerance-enhancer additives, such as melatonin and proline, have been applied along with stress response-inducing elicitors. The use of stress-inducing materials such as PEG and NaCl activates stress tolerance elicitors with the potential of increasing secondary metabolites content of MAOPs. The present study reviewed the state-of-the-art traditional in vitro strategies to manipulate bioactive compounds of MAOPs. The objective is to provide insights to researchers involved in in vitro production of plant-derived natural compounds. The present review provided a wide range of traditional strategies to increase the accumulation of valuable bioactive compounds of MAOPs in different in vitro systems. Traditional strategies are faster, simpler, and cost-effective than other biotechnology-based breeding methods such as genetic transformation, genome editing, metabolic pathways engineering, and synthetic biology. The integrate application of precursors and elicitors along with culture media optimization and the interpretation of their interactions through machine learning algorithms could provide an excellent opportunity for large-scale in vitro production of pharmaceutical bioactive compounds.

A non-reactive natural product precursor of the duocarmycin family has potent and selective antimalarial activity

We identify a selective nanomolar inhibitor of blood-stage malarial proliferation from a screen of microbial natural product extracts. The responsible compound, PDE-I2, is a precursor of the anticancer duocarmycin family that preserves the class's sequence-specific DNA binding but lacks its signature DNA alkylating cyclopropyl warhead. While less active than duocarmycin, PDE-I2 retains comparable antimalarial potency to chloroquine. Importantly, PDE-I2 is >1,000-fold less toxic to human cell lines than duocarmycin, with mitigated impacts on eukaryotic chromosome stability. PDE-I2 treatment induces severe defects in parasite nuclear segregation leading to impaired daughter cell formation during schizogony. Time-of-addition studies implicate parasite DNA metabolism as the target of PDE-I2, with defects observed in DNA replication and chromosome integrity. We find the effect of duocarmycin and PDE-I2 on parasites is phenotypically indistinguishable, indicating that the DNA binding specificity of duocarmycins is sufficient and the genotoxic cyclopropyl warhead is dispensable for the parasite-specific selectivity of this compound class.

Designer nanoparticles for plant cell culture systems: Mechanisms of elicitation and harnessing of specialized metabolites.

Plant cell culture systems have become an attractive and sustainable approach to produce high-value and commercially significant metabolites under controlled conditions. Strategies involving elicitor supplementation into plant cell culture media are employed to mimic natural conditions for increasing the metabolite yield. Studies on nanoparticles (NPs) that have investigated elicitation of specialized metabolism have shown the potential of NPs to be a substitute for biotic elicitors such as phytohormones and microbial extracts. Customizable physicochemical characteristics allow the design of monodispersed-, stimulus-responsive-, and hormone-carrying-NPs of precise geometries to enhance their elicitation capabilities based on target metabolite/plant cell culture type. We contextualize advances in NP-mediated elicitation, especially stimulation of specialized metabolic pathways, the underlying mechanisms, impacts on gene regulation, and NP-associated cytotoxicity. The novelty of the concept lies in unleashing the potential of designer NPs to enhance yield, harness metabolites, and transform nanoelicitation from exploratory investigations to a commercially viable strategy.