Combination of Anoectochilus roxburghii Polysaccharide and Exercise Ameliorates Diet-Induced Metabolic Disorders in Obese Mice

Metabolic syndrome is a cluster of metabolic disorders that threatens public health. Nevertheless, its exact mechanism and relative intervention remain largely obscure. Accumulating evidence indicate that tither Anoectochilus roxburghii polysaccharide (ARP) or exercise (EX) exhibited the beneficial effects on metabolic health. However, the synergetic beneficial effects of ARP and EX as a combined intervention on obesity-induced metabolic disorders remain largely obscure. Male C57BL/6 mice were fed a high-fat diet (HFD) and intervened with ARP and EX for 12 continuous weeks. The results indicated that the ARP, EX, and ARP combined with EX treatment group regulated lipogenesis by suppressing the fatty acid pathway, dampening the system oxidative stress by stimulating Nrf2-mediated phase II enzyme system, and promoting the mitochondrial function by activating the mitochondrial complexes and PGC-1α in HFD mice. More importantly, the combination of ARP and EX showed an even greater beneficial effects relative to either ARP or EX alone, especially in decreasing reactive oxygen species (ROS) level and increasing adenosine triphosphate (ATP) content. Taken together, these findings further confirmed that ARP and EX could be effective interventions on obesity-induced metabolic abnormalities, and that the combination of ARP and EX exhibited the beneficial synergetic effects.

Overexpression of EiKCS confers paraquat-tolerance in rice (Oryza sativa L.) by promoting polyamine pathway

Paraquat is an important bipyridine herbicide by acting on the photosynthetic system of the plants and generating reactive oxygen species leading to cell death, whereas the mechanism of the paraquat resistance remains to be explored. In this study, a putative paraquat-resistant gene EiKCS from goosegrass (Eleusine indica L.) was isolated and overexpressed in a transgenic rice (Oryza sativa L.). This transgenic rice (KCSox) was treated by exogenous spermidine and paraquat and then was analyzed by qualitative and quantitative proteomics. Overexpressing of EiKCS enhanced paraquat tolerance in KCSox by the accumulation of endogenous polyamines whose dominant presences of polyamines benzoylation derivatizations in rice were C18H20N2O2, C28H31N3O3, and C38H42N4O4. The mechanism underlying the improving tolerance enhanced antioxidant capacity of ROS systems and light-harvesting in photosynthesis in KCSox rice leaves to reducing paraquat toxicity. The protein β-Ketoacyl-CoA Synthase (EiKCS) encoded by the EiKCS gene promoted the synthesis and metabolism of proteins of the polyamine pathway. Three cofactors CERs were identified and positively correlated with the function of EiKCS on very-long-chain fatty acids (VLCFAs) biosynthesis via promoting the polyamine pathway and inhibiting the links with the TCA pathway and fatty acid pathway to responding to the paraquat tolerance in the KCSox rice, which also caused the prolongation of the overproduction of spermine and a transient increase of intracellular malondialdehyde (MDA). These results expanded the polyamines pathway manipulated in cereals using genetic engineering to clarify the mechanism of paraquat-tolerance.

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

ABSTRACTMalaria 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.

Fine-Tuning of the Fatty Acid Pathway by Synthetic Antisense RNA for Enhanced (2S)-Naringenin Production from l-Tyrosine in Escherichia coli

ABSTRACTMalonyl coenzyme A (malonyl-CoA) is an important precursor for the synthesis of natural products, such as polyketides and flavonoids. The majority of this cofactor often is consumed for producing fatty acids and phospholipids, leaving only a small amount of cellular malonyl-CoA available for producing the target compound. The tuning of malonyl-CoA into heterologous pathways yields significant phenotypic effects, such as growth retardation and even cell death. In this study, fine-tuning of the fatty acid pathway inEscherichia coliwith antisense RNA (asRNA) to balance the demands on malonyl-CoA for target-product synthesis and cell health was proposed. To establish an efficient asRNA system, the relationship between sequence and function for asRNA was explored. It was demonstrated that the gene-silencing effect of asRNA could be tuned by directing asRNA to different positions in the 5′-UTR (untranslated region) of the target gene. Based on this principle, the activity of asRNA was quantitatively tailored to balance the need for malonyl-CoA in cell growth and the production of the main flavonoid precursor, (2S)-naringenin. Appropriate inhibitory efficiency of the anti-fabB/fabFasRNA improved the production titer by 431% (391 mg/liter). Therefore, the strategy presented in this study provided a useful tool for the fine-tuning of endogenous gene expression in bacteria.