Effects of conjugated linoleic acid (CLA) on fat accumulation, activity, and proteomics analysis in Caenorhabditis elegans

Metabolic Regulation of Longevity and Immune Response in Caenorhabditis elegans by Ingestion of Lacticaseibacillus rhamnosus IDCC 3201 Using Multi-Omics Analysis

Probiotics, specifically Lacticaseibacillus rhamnosus, have garnered attention for their potential health benefits. This study focuses on evaluating the probiotic properties of candidate probiotics L. rhamnosus IDCC 3201 (3201) using the Caenorhabditis elegans surrogate animal model, a well-established in vivo system for studying host-bacteria interactions. The adhesive ability to the host's gastrointestinal tract is a crucial criterion for selecting potential probiotic bacteria. Our findings demonstrated that 3201 exhibits significantly higher adhesive capabilities compared with Escherichia coli OP50 (OP50), a standard laboratory food source for C. elegans and is comparable with the widely recognized probiotic L. rhamnosus GG (LGG). In lifespan assay, 3201 significantly increased the longevity of C. elegans compared with OP50. In addition, preconditioning with 3201 enhanced C. elegans immune response against four different foodborne pathogenic bacteria. To uncover the molecular basis of these effects, transcriptome analysis elucidated that 3201 modulates specific gene expression related to the innate immune response in C. elegans. C-type lectin-related genes and lysozyme-related genes, crucial components of the immune system, showed significant upregulation after feeding 3201 compared with OP50. These results suggested that preconditioning with 3201 may enhance the immune response against pathogens. Metabolome analysis revealed increased levels of fumaric acid and succinic acid, metabolites of the citric acid cycle, in C. elegans fed with 3201 compared with OP50. Furthermore, there was an increase in the levels of lactic acid, a well-known antimicrobial compound. This rise in lactic acid levels may have contributed to the robust defense mechanisms against pathogens. In conclusion, this study demonstrated the probiotic properties of the candidate probiotic L. rhamnosus IDCC 3201 by using multi-omics analysis.

Food preference-based screening method for identification of effectors of substance use disorders using Caenorhabditis elegans

Substance use disorder (SUD) affects over 48 million Americans aged 12 and over. Thus, identifying novel chemicals contributing to SUD will be critical for developing efficient prevention and mitigation strategies. Considering the complexity of the actions and effects of these substances on human behavior, a high-throughput platform using a living organism is ideal. We developed a quick and easy screening assay using Caenorhabditis elegans. C. elegans prefers high-quality food (Escherichia coli HB101) over low-quality food (Bacillus megaterium), with a food preference index of approximately 0.2, defined as the difference in the number of worms at E. coli HB101 and B. megaterium over the total worm number. The food preference index was significantly increased by loperamide, a μ-opioid receptor (MOPR) agonist, and decreased by naloxone, a MOPR antagonist. These changes depended on npr-17, a C. elegans homolog of opioid receptors. In addition, the food preference index was significantly increased by arachidonyl-2'-chloroethylamide, a cannabinoid 1 receptor (CB1R) agonist, and decreased by rimonabant, a CB1R inverse agonist. These changes depended on npr-19, a homolog of CB1R. These results suggest that the conserved opioid and endocannabinoid systems modulate the food preference behaviors of C. elegans. Finally, the humanoid C. elegans strains where npr-17 was replaced with human MOPR and where npr-19 was replaced with human CB1R phenocopied the changes in food preference by the drug treatment. Together, the current results show that this method can be used to rapidly screen the potential effectors of MOPR and CB1R to yield results highly translatable to humans.

Conjugated linoleic acid (CLA) as a functional food: Is it beneficial or not?

Conjugated linoleic acid (CLA) has attracted great attention in recent years as a popular class of functional food that is broadly used. It refers to a group of geometric and positional isomers of linoleic acid (LA) with a conjugated double bond. The main natural sources of CLA are dairy products, beef and lamb, whereas only trace amounts occur naturally in plant lipids. CLA has been shown to improve various health issues, having effects on obesity, inflammatory, anti-carcinogenicity, atherogenicity, immunomodulation, and osteosynthesis. Also, compared to studies on humans, many animal researches reveal more positive benefits on health. CLA represents a nutritional avenue to improve lifestyle diseases and metabolic syndrome. Most of these effects are attributed to the two major CLA isomers [conjugated linoleic acid cis-9,trans-11 isomer (c9,t11), and conjugated linoleic acid trans-10,cis-12 isomer (t10,c12)], and their mixture (CLA mix). In contrast, adverse effects of CLA have been also reported, such as glucose homeostasis, insulin resistance, hepatic steatosis and induction of colon carcinogenesis in humans, as well as milk fat inhibition in ruminants, lowering chicken productivity, influencing egg quality and altering growth performance in fish. This review article aims to discuss the health benefits of CLA as a nutraceutical supplement and highlight the possible mechanisms of action that may contribute to its outcome. It also outlines the feasible adverse effects of CLA besides summarizing the recent peer-reviewed publications on CLA to ensure its efficacy and safety for proper application in humans.

Astaxanthin reduces fat storage in a fat-6/fat-7 dependent manner determined using high fat Caenorhabditis elegans

Although astaxanthin has been shown to have high potential for weight loss, the specific action site and signal pathway generally cannot be confirmed in other animal models. This prevents us from finding therapeutic targets. Hence, we further illuminated its efficacy and specific action sites by using Caenorhabditis elegans (C. elegans). In this study, 60 μM astaxanthin supplementation reduced overall fat deposition and triglyceride levels by 21.47% and 22.00% (p < 0.01). The content of large lipid droplets was reversed after astaxanthin treatment, and the ratio of oleic acid/stearic acid (C18:1Δ9/C18:0) decreased significantly, which were essential substrates for triglyceride biosynthesis. In addition, astaxanthin prevented obesity caused by excessive energy accumulation and insufficient energy consumption. Furthermore, the above effects were induced by sbp-1/mdt-15 and insulin/insulin-like growth factor pathways, and finally co-regulated the specific site-fat-6 and fat-7 down-regulation. These results provided insight into therapeutic targets for future astaxanthin as a nutritional health product to relieve obesity.

miR-497 Regulates LATS1 through the PPARG Pathway to Participate in Fatty Acid Synthesis in Bovine Mammary Epithelial Cells

Nutrient metabolism is required to maintain energy balance in animal organisms, and fatty acids play an irreplaceable role in fat metabolism. In this study, microRNA sequencing was performed on mammary gland tissues collected from cows during early, peak, and late lactation to determine miRNA expression profiles. Differentially expressed miRNA (miR-497) was selected for functional studies of fatty acid substitution. Simulants of miR-497 impaired fat metabolism [triacylglycerol (TAG) and cholesterol], whereas knockdown of miR-497 promoted fat metabolism in bovine mammary epithelial cells (BMECs) in vitro. In addition, in vitro experiments on BMECs showed that miR-497 could down-regulate C16:1, C17:1, C18:1, and C20:1 as well as long-chain polyunsaturated fats. Thus, these data expand the discovery of a critical role for miR-497 in mediating adipocyte differentiation. Through bioinformatics analysis and further validation, we identified large tumor suppressor kinase 1 (LATS1) as a target of miR-497. siRNA-LATS1 increased concentrations of fatty acids, TAG, and cholesterol in cells, indicating an active role of LATS1 in milk fat metabolism. In summary, miR-497/LATS1 can regulate the biological processes associated with TAG, cholesterol, and unsaturated fatty acid synthesis in cells, providing an experimental basis for further elucidating the mechanistic regulation of lipid metabolism in BMECs.

Reproductive toxicity of enrofloxacin in Caenorhabditis elegans involves oxidative stress-induced cell apoptosis

Fluoroquinolone antibiotics (FQs) that persist and bioaccumulate in the environment have aroused people's great concern. Here, we studied the adverse effects of FQs in soil animals of Caenorhabditis elegans via food-chronically exposure. The result shows C. elegans exposed to FQs exhibited reproductive toxicity with small-brood size and low-egg hatchability. To study the underlying mechanism, we conduct a deep investigation of enrofloxacin (ENR), one of the most frequently detected FQs, on nematodes which is one of commonly used animal indicator of soil sustainability. The concentration-effect curves simulated by the Hill model showed that the half effect concentrations (EC₅₀) of ENR were (494.3 ± 272.9) µmol/kg and (107.4 ± 30.9) µmol/kg for the brood size and the hatchability, respectively. Differential gene expression between the control and the ENR-exposure group enriched with the oxidative stress and cell apoptosis pathways. The results together with the enzyme activity in oxidative stress and the cell corpses suggested that ENR-induced reproductive toxicity was related to germ cell apoptosis under oxidative stress. The risk quotients of some soil and livestock samples were calculated based on the threshold value of EC₁₀ for the egg hatchability (2.65 µmol/kg). The results indicated that there was possible reproductive toxicity on the nematodes in certain agricultural soils for the FQs. This study suggested that chronic exposure to FQs at certain levels in environment would induce reproductive toxicity to the nematodes and might reduce the soil sustainability, alarming the environment risks of antibiotics abuse.

Fosthiazate exposure induces oxidative stress, nerve damage, and reproductive disorders in nontarget nematodes

As a forceful nematicide, fosthiazate has been largely applied in the management of root-knot nematodes and other herbivorous nematodes. However, the toxicity of fosthiazate to nontarget nematodes is unclear. To explore the toxicity and the mechanisms of fosthiazate in nontarget nematodes, Caenorhabditis elegans was exposed to 0.01-10 mg/L fosthiazate. The results implied that treatment with fosthiazate at doses above 0.01 mg/L could cause injury to the growth, locomotion behavior, and reproduction of the nematodes. Moreover, L1 larvae were more vulnerable to fosthiazate exposure than L4 larvae. Reactive oxygen species (ROS) production and lipofuscin accumulation were fairly increased in 1 mg/L fosthiazate-exposed nematodes. Treatment with 0.1 mg/L fosthiazate significantly inhibited the activity of acetylcholinesterase (p < 0.01). Furthermore, subacute exposure to 10 mg/L fosthiazate strongly influenced the expression of genes related to oxidative stress, reproduction, and nerve function (e.g., gst-1, sod-1, puf-8, wee-1.3, and ace-1 genes). These findings suggested that oxidative stress, reproduction and nerve disorders could serve as key endpoints of toxicity induced by fosthiazate. The cyp-35a family gene was the main metabolic fosthiazate in C. elegans, and the cyp-35a5 subtype was the most sensitive, with a change in expression level of 2.11-fold compared with the control. These results indicate that oxidative stress and neurological and reproductive disorders played fundamental roles in the toxicity of fosthiazate in C. elegans and may affect the abundance and function of soil nematodes.

Litchi flower essential oil balanced lipid metabolism through the regulation of DAF-2/IIS, MDT-15/SBP-1, and MDT-15/NHR-49 pathway

Many litchi flowers are discarded in China every year. The litchi flower is rich in volatile compounds and exhibits strong anti-obesity activity. Litchi flower essential oil (LFEO) was extracted by the continuous phase transformation device (CPTD) independently developed by our research group to recycle the precious material resources in litchi flowers. However, its fat-reducing effect and mechanism remain unclear. Employing Caenorhabditis elegans as a model, we found that LFEO significantly reduced fat storage and triglyceride (TG) content in normal, glucose-feeding, and high-fat conditions. LFEO significantly reduced body width in worms and significantly decreased both the size and number of lipid droplets in ZXW618. LFEO treatment did not affect energy intake but increased energy consumption by enhancing the average speed of worms. Further, LFEO might balance the fat metabolism in worms by regulating the DAF-2/IIS, sbp-1/mdt-15, and nhr-49/mdt-15 pathways. Moreover, LFEO might inhibit the expression of the acs-2 gene through nhr-49 and reduce β-oxidation activity. Our study presents new insights into the role of LFEO in alleviating fat accumulation and provides references for the large-scale production of LFEO to promote the development of the litchi circular economy.

Caenorhabditis elegans as an in vivo model for food bioactives: A review

Caenorhabditis elegans (C. elegans) is being widely explored as an in vivo model to study the effects of food bioactives. These nematodes are largely advantageous over other in vivo models as they are relatively inexpensive, have a short generation time, and have a completely sequenced genome, among other advantages. C. elegans is a commonly used model to study diseases such as Alzheimer's and Parkinson's disease; however, researchers are finding they can also give insight into the health promoting effect of food-derived bioactive compounds. As consumers become more aware of the health benefits of the foods that they consume, the study of bioactive properties of foods and food constituents is becoming an important source of information. This review focuses on the advantages of using C. elegans as a model such as their short lifespans, high level of gene conservation relative to humans, and large number of progenies per reproductive cycle. They are also easily manipulated in order to perform controlled experiments on synchronous populations. Through review of recent literature, it is clear that C. elegans can be used to study a range of food derived compounds such as bioactive peptides, phenolic compounds, carbohydrates, and lipids. This review also provides information on potential challenges associated with working with this nematode. These challenges include the need for a sterile environment, potential inaccuracy when determining if the nematodes are dead, and the simplicity of the organism making it not suitable for all studies.

Effects of conjugated linoleic acid on growth performance, nutrient digestibility and blood biochemical indexes of male sika deer (Cervus nippon)

ContextConjugated linoleic acid (CLA) is very important for animals and humans. CLA has many important biological functions, such as reducing fat and increasing muscle, antioxidation, improving immunity and so on. CLA requirements for deer have not been established.AimsA single-factor test was conducted to evaluate the effects of CLA supplementation on male sika deer.MethodsSixteen deer were divided in four groups (from G0 to G3) of four animals, each according to their bodyweight. Deer in G0 were fed a basal diet without CLA supplementation. Deer in G1, G2 and G3 were fed diets supplemented with CLA at concentrations of 0.25%, 0.5% and 1.0%. Growth performance, nutrient digestibility and blood biochemical indexes were measured.Key resultsThe results suggested that the average daily gain of deer increased with conjugated linoleic acid supplementation (P&lt;0.05); maximal growth performance was seen in G2. The average daily feed intake showed differences among the treatments (P&lt;0.01). The highest average daily feed intake was observed in Group G2. Feed to gain ratio (F:G) in Groups G1, G2 and G3 was different from that in Group G0 (P&lt;0.01). The digestibility of crude protein and ether extract was increased by conjugated linoleic acid concentrations (P&lt;0.05). The alkaline phosphatase activity showed a significant increase (P&lt;0.05) in Groups G2 and G3, compared with Group G0. There were significant differences in cholesterol between G1 and G2 groups (P&lt;0.05).ConclusionsThe results indicated that conjugated linoleic acid supplementation to diet plays a positive role in the growth of sika deer.ImplicationsThis experiment has shown the effects of dietary supplementation with CLA in sika deer breeding. It has layed a good foundation for the application of CLA supplementation in sika deer industry to promote the healthy development of sika deer breeding industry.

Polysaccharides from Volvariella volvacea inhibit fat accumulation in C. elegans dependent on the aak-2/nhr-49-mediated pathway

Volvariella volvacea has bioactivities in improving immunity, anti-oxidation, and alleviating obesity, which is an excellent functional food. Polysaccharide from Volvariella volvacea (VPS), one of the main bioactive components, exerts a potential fat-lowering effect, but its exact mechanism remains unclear. In this study, the effects and molecular pathways of VPS regulate the fat deposition of Caenorhabditis elegans. Results showed that VPS at low (250 μg/ml), medium (500 μg/ml) and high (750 μg/ml) concentrations all reduced the overall fat, without inhibitory effects on the growth and movement abilities of nematode. VPS at 500 μg/ml could dramatically decrease the triglyceride (TG) level of wild-type nematode, while no significant changes in TG content were observed in mutants deficient in aak-2 (energy receptor), nhr-49 (nuclear transcription factor), fat-5, and fat-7 genes. VPS declines fat storage of C. elegans, largely through the aak-2/nhr-49-mediated fatty acid synthesis pathway, and partially the acs-2-mediated fatty acid oxidation pathway. PRACTICAL APPLICATIONS: A model illustrates the mechanism of polysaccharide from Volvariella volvacea (VPS) inhibiting fat accumulation in Caenorhabditis elegans. VPS may directly or indirectly activate the energy sensor aak-2, which governs lipid metabolism. Results demonstrate that VPS regulates fat metabolism including fatty acid oxidation (FAO) and fatty acid synthesis (FAS), rather than lipolysis. In the FAO, VPS promotes FAO by up-regulating the mRNA and protein levels of acs-2. In FAS, VPS significantly down-regulated the transcriptional regulator nhr-49 and the downstream targets fat-5, fat-6, and fat-7, thereby declining the overall fat deposition. In conclusion, VPS inhibits the fat accumulation of C. elegans largely dependent on an aak-2/nhr-49-mediated FAS pathway.

Curcumin reduced fat accumulation in Caenorhabditis elegans

Curcumin, the primary bioactive substance in turmeric, is known to be associated with weight loss. In this study, we employed Caenorhabditis elegans, a well-established in vivo nematode model to explore the role of curcumin in regulating lipid metabolism. C. elegans administrated with curcumin (10, 25 and 50 μM) exhibited significantly reduced fat accumulation, along with smaller body size (width) when compared to the control, without significantly affecting the feeding behavior. Locomotive activity (average moving speed) was significantly increased by curcumin treatment, suggesting a potential increase in energy expenditure. The reduced fat accumulation by curcumin was dependent on lipogenesis-associated genes, sbp-1 (encodes the homolog of sterol response element binding proteins) and fat-6 (encodes a homolog of stearoyl-CoA desaturase), as curcumin significantly down-regulated the expression levels of these two genes and its fat reduction effect was nulled by the mutation of sbp-1 and fat-6. Additionally, the increased locomotive activity by curcumin was dependent on sbp-1. Current results suggest that curcumin decreases fat accumulation by inhibiting sbp-1/fat-6-mediated signaling in Caenorhabditis elegans.

Physical Stability, Oxidative Stability, and Bioactivity of Nanoemulsion Delivery Systems Incorporating Lipophilic Ingredients: Impact of Oil Saturation Degree

There is great interest in the application of a lipid-based delivery system (like nanoemulsion) to improve the bioavailability of lipophilic components. Although emulsion characteristics are believed to be influenced by oil types, there is still a lack of systematic research concentrating on the effect of oil saturation degree on the nanoemulsion quality, especially for evaluation of the bioactivity. Here, we aimed to test the effect of oil saturation degree on the physical stability, oxidative stability, and bioactivity of the designed nanoemulision system. Our findings suggest that the oxidative stability and bioactivity of a nanoemulsion incorporating tocopherol and sesamol highly depend on the oil saturation. A nanoemulsion with an oil with a high degree of unsaturation was more susceptible to oxidation, and addition of tocopherol and sesamol could retard the lipid oxidation. Sesamol exhibited better bioactivity during the experiment compared with tocopherol in the Caenorhabditis elegans (C. elegans) model. The lipid-lowering effect of tocopherol and sesamol increased with lower saturation oil groups. The antioxidant activity of tocopherol and sesamol was higher in the high saturation oil groups. Overall, the obtained data is meaningful for applications using the designed systems to deliver lipophilic ingredients.

Revealing the antiaging effects of cereal- and food oil-derived active substances by a Caenorhabditis elegans model

Cereal grains and oils contain various functional ingredients, such as amino acids, peptides, polyphenols, dietary fiber, linoleic acid, and natural pigments. Their biological activities are of great significance. Benefiting from its robust genetic function and simple cultivation, Caenorhabditis elegans, as one of the most important model organisms has been widely used to screen antiaging substances and investigate the underlying molecular mechanisms. In this paper, the recent advances in the use of C. elegans in antiaging research into active substances from cereals and oils will be assessed, and their potential signal transduction mechanisms will be systematically reviewed. This research aims to provide a theoretical reference for the use of active substances from cereals and oils to prevent and delay aging and aging-associated diseases.

Trilobatin, a Component from Lithocarpus polystachyrus Rehd., Increases Longevity in C. elegans Through Activating SKN1/SIRT3/DAF16 Signaling Pathway

Trilobatin (TLB) is an effective component from Lithocarpus polystachyrus Rehd. Our previous study revealed that TLB protected against oxidative injury in neuronal cells by AMPK/Nrf2/SIRT3 signaling pathway. However, whether TLB can delay aging remains still a mystery. Therefore, the present study was designed to investigate the possible longevity-enhancing effect of TLB, and further to explore its underlying mechanism in Caenorhabditis elegans (C. elegans). The results showed that TLB exerted beneficial effects on C. elegans, as evidenced by survival rate, body movement assay and pharynx-pumping assay. Furthermore, TLB not only significantly decreased ROS and MDA levels, but also increased anti-oxidant enzyme activities including CAT and SOD, as well as its subtypes SOD2 andSOD3, but not affect SOD1 activity, as evidenced by heat and oxidative stress resistance assays. Whereas, the anti-oxidative effects of TLB were almost abolished in SKN1, Sir2.3, and DAF16 mutant C. elegans. Moreover, TLB augmented the fluorescence intensity of DAF16: GFP, SKN1:GFP, GST4:GFP mutants, indicating that TLB increased the contents of SKN1, SIRT3 and DAF16 due to fluorescence intensity of these mutants, which were indicative of these proteins. In addition, TLB markedly increased the protein expressions of SKN1, SIRT3 and DAF16 as evidenced by ELISA assay. However, its longevity-enhancing effect were abolished in DAF16, Sir2.3, SKN1, SOD2, SOD3, and GST4 mutant C. elegans than those of non-TLB treated controls. In conclusion, TLB effectively prolongs lifespan of C. elegans, through regulating redox homeostasis, which is, at least partially, mediated by SKN1/SIRT3/DAF16 signaling pathway.

Perfluorooctanesulfonic acid (PFOS) and perfluorobutanesulfonic acid (PFBS) impaired reproduction and altered offspring physiological functions in Caenorhabditis elegans

Perfluorobutanesulfonic acid (PFBS), a shorter chain Per- and polyfluoroalkyl substances (PFASs) cognate of perfluorooctanesulfonic acid (PFOS), has been used as replacement for the toxic surfactant PFOS. However, emerging evidences suggest safety concerns for PFBS and its effect on reproductive health is still understudied. Therefore, the current work aimed to investigate the effect of PFBS, in comparison to PFOS, on reproductive health using Caenorhabditis elegans as an in vivo animal model. PFOS (≥10 μM) and PFBS (≥1000 μM) significantly impaired the reproduction capacity of C. elegans, represented as reduced brood size (total egg number) and progeny number (hatched offspring number), without affecting the hatchability. Additionally, the preconception exposure of PFOS and PFBS significantly altered the embryonic nutrient loading and composition, which further led to abnormalities in growth rate, body size and locomotive activity in F1 offspring. Though the effective exposure concentration of PFBS was approximately 100 times higher than PFOS, the internal concentration of PFBS was lower than that of PFOS to produce the similar effects of PFOS. In conclusion, PFOS and PFBS significantly impaired the reproductive capacities in C. elegans and the preconception exposure of these two compounds can lead to offspring physiological dysfunctions.

Fat-lowering effects of isorhamnetin are via NHR-49-dependent pathway in Caenorhabditis elegans

Isorhamnetin (3-O-methylquercetin), a flavonol found in dill weed, sea buckthorn berries, kale and onions, has been suggested to have anti-obesity effects, but there is limited evidence of its mechanisms of action on lipid metabolism. The goal of this study was to investigate the effects of isorhamnetin on lipid metabolism using Caenorhabditis elegans as an animal model. Isorhamnetin reduced fat accumulation without affecting food intake or energy expenditure in C. elegans. The isorhamnetin's fat-lowering effects were dependent on nhr-49, a homolog of the human peroxisome proliferator-activated receptor alpha (PPARα). Isorhamnetin upregulated an enoyl-CoA hydratase (ech-1.1, involved in fatty acid β-oxidation) and adipose triglyceride lipase (atgl-1, involved in lipolysis) via NHR-49-dependent pathway at transcriptional levels. Isorhamnetin also upregulated the C. elegans AMP-activated protein kinase (AMPK) subunits homologs (aak-1 and aak-2), involved in energy homeostasis. These results suggest that isorhamnetin reduces body fat by increasing fat oxidation in part via NHR-49/PPARα-dependent pathway.

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Isorhamnetin reduced fat accumulation in Caenorhabditis elegans.

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Food intake and energy expenditure were not changed by isorhamnetin.

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Isorhamnetin's fat-lowering effects were dependent on nhr-49/PPARα.

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Isorhamnetin upregulated transcriptionally AAK/AMPK, which may activate NHR-49.

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Isorhamnetin increased fat breakdown by upregulating ech-1.1/HADHA and atgl-1/ATGL.

Butein inhibits lipogenesis in Caenorhabditis elegans

Butein, a flavonoid found in annatto seeds and lacquer trees, may be used for many health benefits, including the prevention of obesity. However, its anti-obesity effects are not completely understood; in particular, the effects of butein on the regulation of lipid metabolism have not been explained. Thus, the goal of the current study was to determine the effects of butein on lipid metabolism in Caenorhabditis elegans, which is a multi-organ nematode used as an animal model in obesity research. Butein at 70 μM reduced triglyceride content by 27% compared to the control without altering food intake and energy expenditure. The reduced triglyceride content by butein was associated with the downregulation of sbp-1, fasn-1, and fat-7, the lipogenesis-related homologs of sterol regulatory element-binding proteins, fatty acid synthase and stearoyl-CoA desaturase, respectively. Furthermore, fat-7 and skn-1, a homolog of nuclear respiratory factors, were identified as genetic requirements for butein's effects on triglyceride content in C. elegans. The effects of butein on sbp-1 and fasn-1 were dependent on skn-1, but the downregulation of fat-7 was independent of skn-1. These results suggest that the inhibitory effects of butein on lipogenesis are via SKN-1- and FAT-7-dependent pathways in C. elegans.

Effect of Conjugated Linoleic Acid on Memory and Reflex Maturation in Rats Treated During Early Life

In the critical period of neurodevelopment (gestation and lactation), maternal consumption of essential fatty acids (FAs) can alter the offspring cognitive function permanently causing damage. Lipids can regulate neurotrophin and compose brain tissue. However, the effects of maternal consumption of a mixture of conjugated linoleic acid (CLA) on an offspring nervous system are not completely clear. We aimed to investigate the impacts of different CLA concentrations mixed into the maternal diet during early life on neonatal reflex maturation and cognitive functions of the offspring. Three groups were formed: control (CG): receiving a standard diet; CLA1: receiving a diet containing 1% of CLA, and CLA3: receiving a diet containing 3% of CLA, offered during gestation and lactation. After birth, the reflex responses of the offspring were observed from the 1st to the 21st day. After weaning, the animals' anxiety and memory were assessed using open field (OF) and novel object recognition tests. Fatty acids in the breast milk and the offspring's brain were also quantified. The data were analyzed using one-way ANOVA and the Kruskal-Wallis test. CLA1 presented accelerated palmar grasp disappearance versus CLA3 and negative-geotaxis versus CG; and the CLA3 presented increases for most reflexes (cliff-avoidance, vibrissa-placing, negative-geotaxis, and auditory-startle response), and decrease in reflexes palmar grasp and free-fall righting versus CG (p < 0.05). CLA3 group explored less of the OF in the second exposure. CLA1 and CLA3 presented an increased exploration ratio for new objects, which indicates memory improvement. The milk tested from CLA3 demonstrated an increase in polyunsaturated fatty acids (PUFAs), and a decrease in monounsaturated fatty acids. The amount of CLA in milk was greater in CLA1 and CLA3 and in the brain offspring both presented moderated amounts of CLA. Maternal treatment with the CLA mixture induced anticipated reflex maturation and improved memory in the offspring. Even though CLA was detected in the brains in only trace amounts, offspring's brain PUFA and SFA levels were increased. Further studies aimed to delineate the effect of maternal CLA supplementation on offspring's brain lipid metabolism and long-term neurologic outcome are needed to confirm these findings.

Nanoemulsion-based delivery systems for testing nutraceutical efficacy using Caenorhabditis elegans: Demonstration of curcumin bioaccumulation and body-fat reduction

The genome of the nematode Caenorhabditis elegans shares many similarities with that of humans and so it is widely used as a model in pharmaceutical and nutritional studies. C. elegans has a small mouth and therefore very fine lipid particles are required to orally deliver hydrophobic nutraceuticals. In this study, a nanoemulsion-based delivery system was developed to deliver curcumin to C. elegans. Nanoemulsion were fabricated with different mean particle diameters (d₃₂ = 150 nm and 300 nm), lipid types (Medium chain triglyceride, corn, and fish oil), and emulsifier types (Tween 80 and whey protein). The auto-fluorescence intensity of curcumin was used as an indicator of curcumin accumulation in C. elegans. The structure and composition of nanoemulsions had a significant influence on curcumin bioaccumulation in C. elegans. Curcumin bioaccumulation increased with increasing droplet size, was found to be higher in nanoemulsion containing corn oil compared with those containing fish oil or MCT, and was higher for droplets coated by whey protein than by Tween 80. The nematodes treated with curcumin-loaded nanoemulsions showed significantly reduced fat accumulation compared to the control group. This study could provide useful information to widen the application of C. elegans in research involving lipophilic compounds.

Effects of Momordica saponin extract on alleviating fat accumulation in Caenorhabditis elegans

The study offers methods and models for elucidating fat accumulation and mechanisms, valuable for studies of other plant-based nutraceuticals.

trans-Trismethoxy resveratrol decreased fat accumulation dependent on fat-6 and fat-7 in Caenorhabditis elegans

trans-Trismethoxy resveratrol reduced fat accumulation via the regulation of FAT-6 and FAT-7, stearoyl-CoA desaturases homologs, in Caenorhabditis elegans.