Long-term Supplementation of Deep-fried Oil Consumption Impairs Oxidative Stress, Colon Histology and Increases Neurodegeneration.

BACKGROUND: Sesame oil and sunflower oil are popular cooking oils in southern India. Deep-frying is a frequent method of food preparation. Deep-frying at high temperatures has been linked with several disorders, including cancer, diabetes, and unknown metabolic problems. There have been no long-term investigations on the influence of deep-fried oils on PUFA metabolism and pathogenesis. As a result, the current study aimed to explore the effect of deep-fried frying oil on Wistar rats by continuous treatment. Furthermore, the pathophysiology of MSG-induced neurotoxicity in Wistar rats was investigated. METHODS: Wistar rats weighing 200-260 g were used in this study. Female rats were divided into five groups fed with (1) standard chow (control group), (2) unheated sesame oil (UHSO) along with standard chow, and (3) reheated sesame oil (RHSO) along with standard chow, (4) unheated sunflower oil (UHSFO) along with standard chow, and (5) reheated sunflower oil (RHSFO) along with standard chow and continued up to F1 generation. Furthermore, F1 male rats were treated with MSG of 2 g/kg body weight for 10 alternative days and were sacrificed for major tissues. RESULTS: We found that rats treated with RHSO and RHSFO showed increased body weight. Deep-fried oil-fed rats (RHSO and RHSFO) showed a significant increase in total cholesterol- 100 mg/dl, LDL- 23 mg/dl, & TAG-100 mg/dl, when compared to unheated oil rats. Liver function tests revealed that AST and ALT levels were significantly elevated in RHSO and RHSFO when compared to unheated oils and the control group. Inflammatory markers revealed that Hs-CRP (0.35 mg/dl) and LDH levels (6000 U/L) were significantly elevated in RHSO and RHSFO when compared to the unheated oils and control group. RT-PCR results showed significant elevation in the antioxidant genes SOD (twofold) and GPX (3-fold) when compared to UHSO and UHSFO groups. Liver and colon histology showed significant damage in the cell structure of RHSO and RHSFO-treated rats. Further, rats treated with unheated oils and MSG showed statistically significantly higher mRNA expression of neuroplasticity genes CREB, BDNF and reduced NMDA levels (UHSO, UHSFO) when compared to reheated oil groups (RHSO & RHSFO). Proinflammatory marker TNF-α expression was significantly elevated in RHSFO-treated rats when compared to control. Brain histology showed focal damage in glial cell degeneration in rats treated with RHSO and RHSFO when compared to other groups. CONCLUSION: The results from the present study proved that continuous supplementation deep-fried reheated oil consumption increased serum TGL and oxidative stress markers. Impaired liver metabolism and the involvement of the gut-liver-brain axis increased the risk of neurodegeneration.

Maternal supplementation of high-value PUFA-Rich Isochrysis sp. biomass prevents monosodium glutamate-induced neurotoxicity in first-generation Wistar rats.

Prenatal supplementation of high-value PUFA (HVPUFA) is essential for adequate brain development in infants. As marine microalgal derived omega-3 fatty acids are considered an alternative source of fish oil, their neuroprotective role on monosodium glutamate (MSG)-induced neurotoxicity, bioavailability, and disease prevention in first-generation (F1) animals need to be explored at molecular level. This study tested the long term supplementation of microalgal derived ω-3 PUFAs from parent rats to its offspring rats and studied the neuroprotective role in monosodium glutamate (MSG)-induced neurotoxicity in F1 rats. The parent animals were divided into three groups: control, microalgal-administered group (5.7 mg of EPA and 1.4 mg of DHA/kg BW from Isochrysis sp.), and fish oil-administered group (4.2 mg of EPA and 2.9 mg of DHA/kg BW derived from fish oil) (FG) and continued up to F1 generation. The F1 male rats from respective parents were separated for disease induction: group I animals (control) were administered with 500 µl of Milli-q water alone and group II (disease control), III (Microalga), and IV (fish oil) animals were administered with 2 g/kg bodyweight of MSG for 10 alternative days. Microalga-treated F1 rats showed significant HDL (43 mg/dl) levels when compared to their experimental groups. Brain tissues of microalga-treated F1 rats (MG) showed higher concentration of DHA (10.1 mg/100 mg tissue) and ARA (18.7 mg/100 mg tissue) levels and significant reduction of MDA (30 nM mg protein) levels. Furthermore, MSG induced neurotoxicity was ameliorated through the activation of CREB and BDNF genes The mRNA expressions of CREB and BDNF were 1.5-fold higher and NMDA levels were 2.0-fold higher in treated groups compared to disease control group. However, the expressions of antioxidant genes (SOD, catalase, and GPX) and apoptotic genes (Bcl-2 and Caspase-3) were significantly reduced in MG treated F1 rats when compared to disease control rats. Histopathological results also showed minimal focal damage in the tissues of MG F1 rats. Prenatal and continuous supply of microalgal biomass improves brain DHA and greatly reduced the consequences of MSG neurotoxicity in F1 rats.

Iron and methyl jasmonate increase high-value PUFA production by elevating the expression of desaturase genes in marine microalga Isochrysis sp.

AIM: This study investigated the effect of several metabolic enhancers on the expression of fatty acid biosynthetic genes and their influence on the production of high-value PUFA in the marine microalgae Isochrysis sp., CASA CC 101. METHODS AND RESULTS: The effect of the presence of iron (Fe), nicotinic acid (NIC), methyl jasmonate (MJ) and thidiazuron (TDZ) on the expression of the fatty acid desaturase genes Δ6Des, Δ5Des and Δ4Des was studied in cultures of the marine microalga Isochrysis sp., CASA CC 101. The production of high-value PUFA like γ-linolenic acid (GLA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was correlated with these gene expressions. The results showed that MJ, Fe and TDZ significantly increased the lipid content than the control. MJ specifically up-regulated ∆6Des gene expression and thereby increased GLA production. Whereas Fe specifically increased ∆5Des gene expression and thereby increased EPA production. However, Fe and TDZ-treated cells effectively upregulated the expression of ∆4Des and increased the production of DHA when compared with control cells. CONCLUSIONS: Our findings suggest that addition of Fe and MJ in the culture medium triggers the expression of PUFA biosynthetic genes, especially ∆6Des and ∆4Des, in marine microalga Isochrysis sp., CASA CC 101 their presence resulted in increased production of the PUFAs GLA, EPA and DHA. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that the addition of Fe and MJ to the culture media of Isochrysis sp., CASA CC 101 results in up-regulation of its genes Δ4Des, Δ6Des and Δ5Des, and improves the production of PUFA. Therefore, the addition of Fe and MJ to the culture medium is useful to increase the production of high-value PUFA in Isochrysis sp., CASA CC 101 and also to the other micro algal species.

Anti-listerial activity of microalgal fatty acid methyl esters and their possible applications as chicken marinade.

Fatty acid methyl esters (FAMEs) from marine microalgae have been reported to possess antimicrobial activities against several Gram positive and Gram negative bacteria, but a majority of them needs to be explored. The objective of this study was to investigate the antibacterial activity, mechanism of FAMEs from selected marine microalgae against Listeria monocytogenes, and to elucidate its efficacy in food model. The minimum inhibitory concentration of FAMEs was calculated to be 155 µg/mL for Chromulina sp. and 162 µg/mL for Nannochloropsis sp. against L. monocytogenes. Time-killing kinetics showed that FAMEs efficiently inhibited the growth of L. monocytogenes in a time and concentration dependent manner. The mechanism of action of FAMEs was studied by analysing its effects at a MIC on the cellular metabolism, membrane permeability, and membrane integrity of L. monocytogenes. Transmission Electron Microscopy (TEM) results showed that cells exposed to FAMEs showed damaged cell membrane structure with leakage of the internal contents in the cells of L. monocytogenes. Fluorescence microscopy images showed that L. monocytogenes cells treated with FAMEs showed high dead cell population corresponding with propidium iodide positive cells. Furthermore, FAMEs significantly down regulated quorum sensing and biofilm related genes (DegU, FlaE, and FlaD). In vivo therapeutic potential of FAMEs revealed improved Caenorhabditis elegans survival and reduced intestinal colonization during L. monocytogenes infection. Growth of listeria was abolished in chicken meat during the cold storage of 9 days when the samples were pre-treated with FAMEs. These results suggest anti-L. monocytogenes activity of FAMEs and elucidated its use in food control of chicken meat at refrigerated conditions.

Lowering the culture medium temperature improves the omega-3 fatty acid production in marine microalga Isochrysis sp. CASA CC 101.

Marine microalga Isochrysis sp. contains omega-3 fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Environmental factors play a major role in PUFA biosynthesis. Hence, the study focused to optimize factors such as temperature, pH, and photoperiod by response surface methodology (RSM). RSM results showed that the model is significant (p ≤ 0.05) with a high correlation coefficient (R2 = 0.908). The optimum conditions showed that maximum biomass (327 mg/L) at the temperature of 30 °C, pH of 7.5 and 16:8 (Light: Dark cycle), whereas the higher amount of DHA (13.3%) and EPA (9.0%) was observed in the conditions of 18 °C, pH of 7.5 and 16:8 (Light: Dark cycle). The biomass content was directly proportional to the temperature whereas DHA content was inversely proportional. It was revealed that the mRNA expression of EPA and DHA specific desaturases (5Des & 4Des) were significantly elevated in low temperature (20 °C) conditions. The results were highly correlated with the fatty acid profile of Isochrysis sp. grown under low temperature (20 °C) conditions which enhanced the EPA and DHA levels. This study suggests that the temperature is the most influencing factor which can be exploited in the industrial application of DHA and EPA production from Isochrysis sp.

Omega-3-rich Isochrysis sp. biomass enhances brain docosahexaenoic acid levels and improves serum lipid profile and antioxidant status in Wistar rats.

BACKGROUND: Isochrysis sp. is a marine microalga, rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The potential use of its biomass as an alternative source of polyunsaturated fatty acids (PUFAs) has not been studied in animal models. Male albino Wistar rats were divided into three groups and treated for 28 days. The rats were fed with (1) standard chow (control group), (2) microalgal biomass rich in EPA and DHA along with standard chow (microalga group), and (3) fish oil that contains equivalent amounts of EPA and DHA along with standard chow (fish oil group). After intervention, biochemical indices, histopathological indices, relative mRNA expression of PUFA genes, antioxidant genes, inflammatory markers, and the fatty acid profile of major tissues were studied. RESULTS: Animals treated with microalgal biomass showed significantly increased serum HDL levels (P < 0.05) and reduced oxidative stress markers with a concomitant decrease in urea and creatinine levels. Oral supplementation of microalgal biomass did not show any toxicity or damage in any major organs. The mRNA expression of PUFA genes was significantly downregulated (P < 0.05) and antioxidant genes were upregulated. Furthermore, the mRNA expression of pro-inflammatory markers was significantly downregulated (P < 0.05) and anti-inflammatory markers were upregulated. Oral supplementation of microalgal biomass improved DHA status in brain and liver. CONCLUSION: The present study demonstrated that Isochrysis sp. can be used as a safe, alternative food supplement for ω-3 fatty acids. © 2019 Society of Chemical Industry.

Expression of heterologous oxalate decarboxylase in HEK293 cells confers protection against oxalate induced oxidative stress as a therapeutic approach for calcium oxalate stone disease.

Oxalates stimulate alterations in renal epithelial cells and thereby induce calcium oxalate (CaOx) stone formation. Bacillus subtilis YvrK gene encodes for oxalate decarboxylase (OxdC) which degrades oxalate to formate and CO2. The present work is aimed to clone the oxdC gene in a mammalian expression vector pcDNA and transfect into Human Embryonic Kidney 293 (HEK293) cells and evaluate the oxdC expression, cell survival rate and oxalate degrading efficiency. The results indicate cell survival rate of HEK293/pcDNAOXDC cells pre-incubated with oxalate was enhanced by 28%. HEK293/pcDNAOXDC cells expressing OxdC treated with oxalate, significantly restored antioxidant activity, mitochondrial membrane potential and intracellular reactive oxygen species (ROS) generation compared with HEK293/pcDNA. Apoptotic marker caspase 3 downregulation illustrates HEK293/pcDNAOXDC cells were able to survive under oxalate-mediated oxidative stress. The findings suggest HEK293 cells expressing oxdC capable of degrading oxalate protect cells from oxidative damage and thus serve as a therapeutic option for prevention of CaOx stone disease. [Formula: see text].