Beyond the MEP Pathway: A novel kinase required for prenol utilization by malaria parasites.

A proposed treatment for malaria is a combination of fosmidomycin and clindamycin. Both compounds inhibit the methylerythritol 4-phosphate (MEP) pathway, the parasitic source of farnesyl and geranylgeranyl pyrophosphate (FPP and GGPP, respectively). Both FPP and GGPP are crucial for the biosynthesis of several essential metabolites such as ubiquinone and dolichol, as well as for protein prenylation. Dietary prenols, such as farnesol (FOH) and geranylgeraniol (GGOH), can rescue parasites from MEP inhibitors, suggesting the existence of a missing pathway for prenol salvage via phosphorylation. In this study, we identified a gene in the genome of P. falciparum, encoding a transmembrane prenol kinase (PolK) involved in the salvage of FOH and GGOH. The enzyme was expressed in Saccharomyces cerevisiae, and its FOH/GGOH kinase activities were experimentally validated. Furthermore, conditional knockout parasites (Δ-PolK) were created to investigate the biological importance of the FOH/GGOH salvage pathway. Δ-PolK parasites were viable but displayed increased susceptibility to fosmidomycin. Their sensitivity to MEP inhibitors could not be rescued by adding prenols. Additionally, Δ-PolK parasites lost their capability to utilize prenols for protein prenylation. Experiments using culture medium supplemented with whole/delipidated human plasma in transgenic parasites revealed that human plasma has components that can diminish the effectiveness of fosmidomycin. Mass spectrometry tests indicated that both bovine supplements used in culture and human plasma contain GGOH. These findings suggest that the FOH/GGOH salvage pathway might offer an alternate source of isoprenoids for malaria parasites when de novo biosynthesis is inhibited. This study also identifies a novel kind of enzyme related to isoprenoid metabolism.

Licoflavone B, an isoprene flavonoid derived from licorice residue, relieves dextran sodium sulfate-induced ulcerative colitis by rebuilding the gut barrier and regulating intestinal microflora.

Ulcerative colitis (UC) is a major inflammatory disease worldwide. We previously demonstrated that licorice residue flavones (LFs) showed satisfactory efficacy in the treatment of UC. Therefore, research into the ingredients of LFs may lead to the discovery of novel anti-UC targets. In the current study, we separated licoflavone B (LB) from LFs and administered it to dextran sodium sulfate (DSS)-exposed C57BL/6 mice for 14 days. Our results demonstrated that high dose LB (120 mg/kg) significantly prevented DSS-induced weight loss, disease activity index (DAI) increase, histological damage, and colonic inflammation, indicating that LB has ameliorative effects on UC. We also investigated the composition of the intestinal barrier and microflora in an attempt to explore the mechanisms of LB against UC. As a result, we found that LB preserved the integrity of the colonic barrier by inhibiting colonic cell apoptosis and protecting the expression of occludin, claudin-1, and ZO-1. Moreover, LB reshaped the microflora composition by suppressing harmful bacteria (Enterococcus et al.) and boosting beneficial microorganisms (Bacteroides et al.). Further molecular exploration implied that LB exerted anti-UC activity through blocking the MAPK pathway. Here, we explored anti-UC activity of LB for the first time and clarified its mechanisms. These results will provide valuable clues for the discovery of novel anti-UC agents.

Hemiterpene compound, 3,3-dimethylallyl alcohol promotes longevity and neuroprotection in Caenorhabditis elegans.

Terpenes and their derivatives have been used conventionally as potential dietary supplements to boost the nutritional value of endless food products. Several plant-based complex terpenoid and their derivatives have been reported for a wide range of medicinal and nutritional properties. However, their simple counterparts, whose production is relatively easy, sustainable, and economic from food-grade microbial sources, have not been studied yet for any such biological activities. The present study aimed to investigate the longevity-promoting property and neuromodulatory effects of 3,3-dimethylallyl alcohol (Prenol), one of the simplest forms of terpenoid and a constituent of fruit aroma, in the animal model Caenorhabditis elegans. Prenol supplementation (0.25 mM) augmented the lifespan of wild-type nematodes by 22.8% over the non-treated worms. Moreover, a suspended amyloid-ß induced paralysis and reduced α-synuclein aggregation were observed in Prenol-treated worms. The lifespan extending properties of Prenol were correlated with ameliorated physiological parameters and increased stress (heat and oxidative) tolerance in C. elegans. In silico and gene-specific mutant studies showed that pro-longevity transcription factors DAF-16, HSF-1, and SKN-1 were involved in the improved lifespan and health-span of Prenol-treated worms. Transgenic green fluorescent protein-reporter gene expression analysis and relative mRNA quantification (using real-time PCR) demonstrated an increase in the expression of DAF-16, HSF-1, and SKN-1 transcription factors and their downstream target genes in Prenol-treated worms. Together, the findings suggest that small molecules, like Prenol, could be explored as a potential alternate to develop therapeutics against aging and age-related ailments.

Nine prenylated acylphloroglucinols with potential anti-depressive and hepatoprotective activities from Hypericum scabrum.

In our screening program for new biologically active secondary metabolites, nine new polycyclic polyprenyled acylphloroglucinols, hyperscabins D-L, together with three known compounds, were obtained from the aerial parts of Hypericum scabrum. The chemical structures of 1-9 were characterized by extensive spectroscopic analyses, nuclear magnetic resonance calculation with DP4+ probability analysis, and the electronic circular dichroism spectra were calculated. Compound 1 was an unusual prenylated acylphloroglucinol decorated with a 5-oxaspiro [4,5] deca-1,9-dione skeleton. Compound 2 was a newly identified spirocyclic polyprenylated acylphloroglucinol possessing a rare 5,5-spiroketal segment. Compounds 3, 8, and 10 (10 µM) exhibited pronounced hepatoprotective activity against d-galactosamine-induced WB-F344 cell damage in vitro assays. All test compounds (1, 3, and 7-12) demonstrated potential inhibitory effects at 10 µM against noradrenalinet ([3H]-NE) reuptake in rat brain synaptosome.

Ozone impairs the response of isoprene emission to foliar nitrogen and phosphorus in poplar.

Tropospheric ozone (O3) impairs physiological processes of plants while nitrogen (N) deposition may cause imbalances in soil N and other nutrients such as phosphorus (P) suggesting an increase of P demand for plants. However, the combined effect of O3, soil N and P on isoprene emission from leaves has never been tested. We therefore examined isoprene emission in leaves of Oxford poplar clone exposed to O3 (ambient, AA [35.0 nmol mol-1 as daily mean]; 1.5 × AA; 2.0 × AA), soil N (0 and 80 kg N ha-1) and soil P (0, 40 and 80 kg P ha-1) in July and September in a Free-Air Controlled Exposure (FACE) facility. We also investigated the response of isoprene emission to foliar N, P and abscisic acid (ABA) contents in September because the 2-C-methylerythritol-5-phosphate (MEP) pathway of isoprenoid biosynthesis produces ABA. We found that O3 increased isoprene emission in July, which was associated to increased dark respiration, suggesting an activation of metabolism against O3 stress as an initial response. However, O3 decreased isoprene emission in September which was associated to reduced net photosynthesis. In September, isoprene emission was positively correlated with leaf N content and negatively correlated with leaf P content in AA. However, no response of isoprene emission to foliar N and P was found in elevated O3, suggesting that the isoprene responses to foliar N and P depended on the O3 exposure levels. Isoprene emission rate in 1.5 × AA and 2.0 × AA increased with increasing leaf ABA content, indicating accelerated senescence of injured leaves to favor new leaf growth when high O3 and nutritional availability in the soil were combined. Even though foliar N and P usually act as a proxy for isoprene emission rate, the impact of recent abiotic factors such as O3 should be always considered for modeling isoprene emission under climate change.

Chemical Profile and Use of the Peat as an Adsorbent for Extraction of Volatile Compounds from Leaves of Geranium (Pelargonium graveolens L' Herit).

Volatile organic compounds (VOCs) from leaves of geranium (Pelargonium graveolens L' Herit) were extracted by dynamic headspace using Porapak Q (HSD-P) as adsorbent and peat, a novel adsorbent in the extraction of plant volatiles, analyzed by gas chromatography-mass spectrometry (GC/MS) and gas chromatography-flame ionization (GC/FID), and the results were compared with those obtained by hydrodistillation (HD). The yield volatiles changed with the extraction method. HD was more efficient for extracting linalool (11.19%) and citronellyl formate (9.41%). Citronellol (28.06%), geraniol (38.26%) and 6,9-guaiadiene (9.55%) and geranyl tiglate (8.21%) were the major components identified by dynamic headspace using peat (HSD-T), while citronellol (16.88%), geraniol (13.63%), 6,9-guaiadiene (16.98%) and citronellyl formate (6.95%) were identified by dynamic headspace using Porapak Q (HSD-P). Furthermore, this work showed, for the first time, that in natura peat is useful to extract VOCs from leaves of geranium.

Comparison of Chemical Composition between Kuromoji (Lindera umbellata) Essential Oil and Hydrosol and Determination of the Deodorizing Effect.

Kuromoji (Lindera umbellata) is a tree that grows throughout Japan. The components of kuromoji essential oil have antitumor and aromatherapy effects. However, the composition of the hydrosol, obtained as a by-product of the essential oil process, is unknown. Furthermore, it is unknown whether kuromoji essential oil has a deodorizing effect. Therefore, the purpose of the current study was to compare the chemical composition of kuromoji essential oil and hydrosol, as well as evaluate the deodorizing effect of the former. The chemical composition of samples was evaluated using gas chromatography-mass spectrometry (GC-MS). Additionally, the deodorizing effect of Kuromoji essential oil was investigated with the detector tube method using ammonia, hydrogen sulfide, methyl mercaptan, and isovaleric acid. Linalool was the most abundant component in both the essential oil and hydrosol; however, its proportion was higher in the hydrosol (57.5%) than in the essential oil (42.8%). The hydrosol contained fewer chemical components, but higher proportions of trans-geraniol and ethanol. Moreover, the essential oil eliminated 50% of ammonia and 97.6% or more of isovaleric acid. Interestingly, linalool was soluble in the hydrosol and did not irritate the skin. This suggests that the hydrosol may be an effective foot care product.

The Beneficial Effects of Morusin, an Isoprene Flavonoid Isolated from the Root Bark of Morus.

The root bark of Morus has long been appreciated as an antiphlogistic, diuretic and expectorant drug in Chinese herbal medicine, albeit with barely known targets and mechanisms of action. In the 1970s, the development of analytic chemistry allowed for the discovery of morusin as one of 7 different isoprene flavonoid derivatives in the root bark of Morus. However, the remarkable antioxidant capacity of morusin with the unexpected potential for health benefits over the other flavonoid derivatives has recently sparked scientific interest in the biochemical identification of target proteins and signaling pathways and further clinical relevance. In this review, we discuss recent advances in the understanding of the functional roles of morusin in multiple biological processes such as inflammation, apoptosis, metabolism and autophagy. We also highlight recent in vivo and in vitro evidence on the clinical potential of morusin treatment for multiple human pathologies including inflammatory diseases, neurological disorders, diabetes, cancer and the underlying mechanisms.

Analysis of the isoprenoid pathway intermediates, dimethylallyl diphosphate and isopentenyl diphosphate, from crude plant extracts by liquid chromatography tandem mass spectrometry.

OBJECTIVE: We sought to develop a sensitive and accurate analytical method for the detection and quantification of IDP and DMADP as well as their monophosphate derivatives in crude plant extracts. METHODS: A liquid chromatography method coupled to tandem mass spectrometry (LC-MS/MS) with multiple reaction monitoring (MRM) was established to measure the amounts of IDP and DMADP down to low picogram levels, which was linear over at least three orders of magnitude. Extracts were enriched using an anion exchanger, and chromatographic separation was achieved using a ß-cyclodextrin column. A S-thiolodiphosphate analog of DMADP was employed as an internal standard. RESULTS: Dilution series of authentic compounds were used to determine the limits of detection and quantification for IDP, DMADP and their corresponding monophosphates. A survey of plant species producing varying amounts of isoprenoids showed a corresponding variation in IDP and DMADP with the ratio of DMADP/IDP ranging from 4:1 to 2:1. Trace levels of isopentenyl monophosphate (IP) and dimethylallyl monophosphate (DMAP) were also detected. CONCLUSION: The LC-MS/MS method described enables absolute quantification of in planta levels of IDP and DMADP for the first time. The method is also suitable for analysing bacterial and animal samples as well as enzyme assays.

Integrative Analysis of Terpenoid Profiles and Hormones from Fruits of Red-Flesh Citrus Mutants and Their Wild Types.

In citrus color mutants, the levels of carotenoid constituents and other secondary metabolites are different in their corresponding wild types. Terpenoids are closely related to coloration, bitterness, and flavor. In this study, terpenoid profiles and hormones in citrus fruits of two red-flesh mutants-Red Anliu orange and Red-flesh Guanxi pummelo-and their corresponding wild types were investigated using GC/MS, HPLC, and LC-MS/MS. Results showed that Red Anliu orange (high in carotenoids) and Anliu orange (low in carotenoids) accumulated low levels of limonoid aglycones but high levels of monoterpenoids; conversely, Red-flesh Guanxi pummelo (high in carotenoids) and Guanxi pummelo (deficient in carotenoids) accumulated high levels of limonoid aglycones but low levels of monoterpenoids. However, isopentenyl diphosphate was present at similar levels. A correlation analysis indicated that jasmonic and salicylic acids might play important roles in regulating terpenoid biosynthesis. Additionally, the similarities of carotenoid and volatile profiles between each mutant and its corresponding wild type were greater than those between the two mutants or the two wild types. The flux balance of terpenoid metabolism in citrus fruit tends toward stability among various citrus genera that have different terpenoid profiles. Bud mutations could influence metabolite profiles of citrus fruit to a limited extent.

Isovaleric acid and avicequinone-C are Chikungunya virus resistance principles in Glycosmis pentaphylla (Retz.) Correa.

BACKGROUND & OBJECTIVES: Oral administration of tender leaf extract of Glycosmis pentaphylla is traditionally known to prevent the chikungunya virus infection. Even with wide usage, the antiviral components in this plant are neither identified nor characterized. This study was carried out with the objectives of profiling the phytocompounds in this plant through LC-MS/MS and to identify the active antiviral constituents and their drug-likeliness through molecular docking. METHODS: Phytocompounds were extracted hydro-alcoholically from powdered plant parts and analyzed using LC-MS/MS. Based on mass-to-charge ratio from LC-MS/MS, compounds were identified and used as ligands for molecular docking against chikungunya target proteins. The active principles were subjected to ADME/T analysis to verify their drug-likeliness. RESULTS: The docking results and ADME/T evaluation showed that the compounds, isovaleric acid and avicequinone- C have good interaction with the protein targets and hence could be the antiviral principles of the selected plant. These compounds presented acceptable drug properties and hence could be carried forward to in vivo studies for drug development. INTERPRETATION & CONCLUSION: The antiviral properties of G. pentaphylla are known since time-immemorial. This study revealed the probable interactions after the oral administration of tender leaves of Glycosmis in preventing the chikungunya virus infection and paves the path for designing future plant-based drugs.

Gains and losses of metabolic function inferred from a phylotranscriptomic analysis of algae.

Hidden Markov models representing 167 protein sequence families were used to infer the presence or absence of homologs within the transcriptomes of 183 algal species/strains. Statistical analyses of the distribution of HMM hits across major clades of algae, or at branch points on the phylogenetic tree of 98 chlorophytes, confirmed and extended known cases of metabolic loss and gain, most notably the loss of the mevalonate pathway for terpenoid synthesis in green algae but not, as we show here, in the streptophyte algae. Evidence for novel events was found as well, most remarkably in the recurrent and coordinated gain or loss of enzymes for the glyoxylate shunt. We find, as well, a curious pattern of retention (or re-gain) of HMG-CoA synthase in chlorophytes that have otherwise lost the mevalonate pathway, suggesting a novel, co-opted function for this enzyme in select lineages. Finally, we find striking, phylogenetically linked distributions of coding sequences for three pathways that synthesize the major membrane lipid phosphatidylcholine, and a complementary phylogenetic distribution pattern for the non-phospholipid DGTS (diacyl-glyceryl-trimethylhomoserine). Mass spectrometric analysis of lipids from 25 species was used to validate the inference of DGTS synthesis from sequence data.

Modification of isoprene synthesis to enable production of curcurbitadienol synthesis in Saccharomyces cerevisiae.

Cucurbitane-type triterpenoids such as mogrosides and cucurbitacins that are present in the plants of Cucurbitaceae are widely used in Asian traditional medicine. Cucurbitadienol is the skeleton of cucurbitane-type triterpenoids. As an alternative production strategy, we developed baker's yeast Saccharomyces cerevisiae as a microbial host for the eventual transformation of cucurbitadienol. The synthetic pathway of cucurbitadienol was constructed in Saccharomyces cerevisiae by introducing the cucurbitadienol synthase gene from different plants, resulting in 7.80 mg cucurbitadienol from 1 L of fermentation broth. Improving supplies of isoprenoid precursors was then investigated for increasing cucurbitadienol production. Cucurbitadienol production increased to 21.47 mg/L through the overexpression of a global regulatory factor (UPC2) gene of triterpenoid synthase. In addition, knockout of the ERG7 gene increased cucurbitadienol production from 21.47 to 61.80 mg/L. Finally, fed-batch fermentation was performed, and 63.00 mg/L cucurbitadienol was produced. This work is an important step towards the total biosynthesis of valuable cucurbitane-type triterpenoids and demonstrates the potential for developing a sustainable and secure yeast biomanufacturing platform for triterpenoids.

Ancient and modern anticonvulsants act synergistically in a KCNQ potassium channel binding pocket.

Epilepsy has been treated for centuries with herbal remedies, including leaves of the African shrub Mallotus oppositifolius, yet the underlying molecular mechanisms have remained unclear. Voltage-gated potassium channel isoforms KCNQ2-5, predominantly KCNQ2/3 heteromers, underlie the neuronal M-current, which suppresses neuronal excitability, protecting against seizures. Here, in silico docking, mutagenesis and cellular electrophysiology reveal that two components of M. oppositifolius leaf extract, mallotoxin (MTX) and isovaleric acid (IVA), act synergistically to open neuronal KCNQs, including KCNQ2/3 channels. Correspondingly, MTX and IVA combine to suppress pentylene tetrazole-induced tonic seizures in mice, whereas individually they are ineffective. Co-administering MTX and IVA with the modern, synthetic anticonvulsant retigabine creates a further synergy that voltage independently locks KCNQ2/3 open. Leveraging this synergy, which harnesses ancient and modern medicines to exploit differential KCNQ isoform preferences, presents an approach to developing safe yet effective anticonvulsants.

Hypermonins A and B, two 6-norpolyprenylated acylphloroglucinols with unprecedented skeletons from Hypericum monogynum.

Two new 6-norpolycyclic polyprenylated acylphloroglucinols (PPAPs), hypermonins A (1) and B (2), featuring an undescribed decahydroindeno[1,7-bc]furan ring system, were isolated from the leaves and twigs of Hypericum monogynum. These compounds are a pair of epimers with opposite configurations at the C-5 position. Their structures, including their absolute configurations, were determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. A plausible biosynthetic pathway of 1 and 2 was also proposed. Compound 1 exhibited a significant protective effect against corticosterone-induced injury in PC12 cells.

Highly Selective and Rapid Breath Isoprene Sensing Enabled by Activated Alumina Filter.

Isoprene is a versatile breath marker for noninvasive monitoring of high blood cholesterol levels as well as for influenza, end-stage renal disease, muscle activity, lung cancer, and liver disease with advanced fibrosis. Its selective detection in complex human breath by portable devices (e.g., metal-oxide gas sensors), however, is still challenging. Here, we present a new filter concept based on activated alumina powder enabling fast and highly selective detection of isoprene at the ppb level and high humidity. The filter contains high surface area adsorbents that retain hydrophilic compounds (e.g., ketones, alcohols, ammonia) representing major interferants in breath while hydrophobic isoprene is not affected. As a proof-of-concept, filters of commercial activated alumina powder are combined with highly sensitive but rather nonspecific, nanostructured Pt-doped SnO2 sensors. This results in fast (10 s) measurement of isoprene down to 5 ppb at 90% relative humidity with outstanding selectivity (>100) to breath-relevant acetone, ammonia, ethanol, and methanol, superior to state-of-the-art isoprene sensors. Most importantly, when exposed continuously to simulated breath mixtures (four analytes) for 8 days, this filter-sensor system showed stable performance. It can be incorporated readily into a portable breath isoprene analyzer promising for simple-in-use monitoring of blood cholesterol or other patho/physiological conditions.

Effects of isovalerate supplements on morphology and functional gene expression of rumen mucosa in pre- and post-weaning dairy calves.

Isovalerate supplements could stimulate rumen development by improving morphology and function of rumen mucosa, and then promote the growth of calves. This study was done to evaluate the effects of isovalerate supplements on morphology and functional gene expression of rumen mucosa in dairy calves. In total, 48 Chinese Holstein male calves with 15 days of age and 45.1±0.36 kg of BW were randomly assigned to four groups. The treatments were: control, low-isovalerate, moderate-isovalerate and high-isovalerate with 0, 3, 6 and 9 g isovalerate per calf per day, respectively. Supplementary isovalerate was hand-mixed into milk in pre-weaning calves and into concentrate portion in post-weaning calves. The study consisted of a 15-day-adaptation period and a 60-day-sampling period. Calves were weaned at 60 days of age. Three calves were slaughtered from each of the four treatments at 30, 60 and 90 days of age. The weight of body and stomach were measured, samples of ruminal tissues and blood were analyzed. Total stomach weight, total stomach to BW ratio, rumen wall and keratinized layer thickness, serum growth hormone and IGF-1 for both pre- and post-weaning calves increased linearly with increasing isovalerate supplements. Rumen to total stomach weight ratio, the length and width of rumen papillae, and serum ß-hydroxybutyrate increased linearly for post-weaning calves. However, abomasum weight to total stomach weight ratio decreased linearly for both pre- and post-weaning calves. The relative messenger RNA expression for growth hormone receptor, IGF-1 receptor and 3-hydroxy-3-methylglutaryl-CoA synthase 1 in rumen mucosa increased linearly for post-weaning calves. Our results suggested that isovalerate supplements promoted rumen development in a dose-dependent manner. The optimum dose was 6.0 g isovalerate per calf per day.

Nutrient-rich plants emit a less intense blend of volatile isoprenoids.

The emission of isoprenoids (e.g. isoprene and monoterpenes) by plants plays an important defensive role against biotic and abiotic stresses. Little is known, however, about the functional traits linked to species-specific variability in the types and rates of isoprenoids emitted and about possible co-evolution of functional traits with isoprenoid emission type (isoprene emitter, monoterpene emitter or both). We combined data for isoprene and monoterpene emission rates per unit dry mass with key functional traits (foliar nitrogen (N) and phosphorus (P) concentrations, and leaf mass per area) and climate for 113 plant species, covering the boreal, wet temperate, Mediterranean and tropical biomes. Foliar N was positively correlated with isoprene emission, and foliar P was negatively correlated with both isoprene and monoterpene emission rate. Nonemitting plants generally had the highest nutrient concentrations, and those storing monoterpenes had the lowest concentrations. Our phylogenetic analyses found that the type of isoprenoid emission followed an adaptive, rather than a random model of evolution. Evolution of isoprenoids may be linked to nutrient availability. Foliar N and P are good predictors of the type of isoprenoid emission and the rate at which monoterpenes, and to a lesser extent isoprene, are emitted.

Validation of Putative Apicoplast-Targeting Drugs Using a Chemical Supplementation Assay in Cultured Human Malaria Parasites.

Malaria parasites contain a relict plastid, the apicoplast, which is considered an excellent drug target due to its bacterial-like ancestry. Numerous parasiticidals have been proposed to target the apicoplast, but few have had their actual targets substantiated. Isopentenyl pyrophosphate (IPP) production is the sole required function of the apicoplast in the blood stage of the parasite life cycle, and IPP supplementation rescues parasites from apicoplast-perturbing drugs. Hence, any drug that kills parasites when IPP is supplied in culture must have a nonapicoplast target. Here, we use IPP supplementation to discriminate whether 23 purported apicoplast-targeting drugs are on- or off-target. We demonstrate that a prokaryotic DNA replication inhibitor (ciprofloxacin), several prokaryotic translation inhibitors (chloramphenicol, doxycycline, tetracycline, clindamycin, azithromycin, erythromycin, and clarithromycin), a tRNA synthase inhibitor (mupirocin), and two IPP synthesis pathway inhibitors (fosmidomycin and FR900098) have apicoplast targets. Intriguingly, fosmidomycin and FR900098 leave the apicoplast intact, whereas the others eventually result in apicoplast loss. Actinonin, an inhibitor of bacterial posttranslational modification, does not produce a typical delayed-death response but is rescued with IPP, thereby confirming its apicoplast target. Parasites treated with putative apicoplast fatty acid pathway inhibitors could not be rescued, demonstrating that these drugs have their primary targets outside the apicoplast, which agrees with the dispensability of the apicoplast fatty acid synthesis pathways in the blood stage of malaria parasites. IPP supplementation provides a simple test of whether a compound has a target in the apicoplast and can be used to screen novel compounds for mode of action.

Microbiome and metabolome modifying effects of several cardiovascular disease interventions in apo-E-/- mice.

BACKGROUND: There is strong evidence indicating that gut microbiota have the potential to modify, or be modified by the drugs and nutritional interventions that we rely upon. This study aims to characterize the compositional and functional effects of several nutritional, neutraceutical, and pharmaceutical cardiovascular disease interventions on the gut microbiome, through metagenomic and metabolomic approaches. Apolipoprotein-E-deficient mice were fed for 24 weeks either high-fat/cholesterol diet alone (control, HFC) or high-fat/cholesterol in conjunction with one of three dietary interventions, as follows: plant sterol ester (PSE), oat ß-glucan (OBG) and bile salt hydrolase-active Lactobacillus reuteri APC 2587 (BSH), or the drug atorvastatin (STAT). The gut microbiome composition was then investigated, in addition to the host fecal and serum metabolome. RESULTS: We observed major shifts in the composition of the gut microbiome of PSE mice, while OBG and BSH mice displayed more modest fluctuations, and STAT showed relatively few alterations. Interestingly, these compositional effects imparted by PSE were coupled with an increase in acetate and reduction in isovalerate (p < 0.05), while OBG promoted n-butyrate synthesis (p < 0.01). In addition, PSE significantly dampened the microbial production of the proatherogenic precursor compound, trimethylamine (p < 0.05), attenuated cholesterol accumulation, and nearly abolished atherogenesis in the model (p < 0.05). However, PSE supplementation produced the heaviest mice with the greatest degree of adiposity (p < 0.05). Finally, PSE, OBG, and STAT all appeared to have considerable impact on the host serum metabolome, including alterations in several acylcarnitines previously associated with a state of metabolic dysfunction (p < 0.05). CONCLUSIONS: We observed functional alterations in microbial and host-derived metabolites, which may have important implications for systemic metabolic health, suggesting that cardiovascular disease interventions may have a significant impact on the microbiome composition and functionality. This study indicates that the gut microbiome-modifying effects of novel therapeutics should be considered, in addition to the direct host effects.