scholarly journals Who let the fat out?

2018 ◽  
Vol 40 (2) ◽  
pp. 18-21
Author(s):  
Roop Mallik

Cells in all organisms build fatty acid hydrocarbon chains and hook them up with a glycerol molecule to make energy-rich triglycerides (fat, in simple language). These are then stocked away inside cells in micron-sized bodies called lipid droplets (LDs). When glucose levels diminish, LDs are supplied to mitochondria to burn up the fatty acid chains so that ATP can be made to fuel your cells. But, did you know that the same LDs are also fueling your car? Fossil fuels are basically hydrocarbon chains that were hidden away in the LDs of creatures that died millions of years ago. There is now tremendous interest in generating bio-fuel from algae that can store large quantities of LDs. Perhaps this is why the oil companies have cared more about LDs than biologists in the recent past.

2017 ◽  
Vol 68 (11) ◽  
pp. 2676-2681
Author(s):  
Mihaela Gabriela Dumitru ◽  
Dragos Tutunea

The purpose of this work was to investigate the physicochemical properties of watermelon seeds and oil and to find out if this oil is suitable and compatible with diesel engines. The results showed that the watermelon seeds had the maximum length (9.08 mm), width (5.71mm), thickness (2.0 mm), arithmetic mean diameter (5.59 mm), geometrical mean diameter (4.69 mm), sphericity (51.6%), surface area (69.07), volume 0.17 cm3 and moisture content 5.4%. The oil was liquid at room temperature, with a density and refractive index of 0.945 and 1.4731 respectively acidity value (1.9 mgNaOH/g), free fatty acid (0.95 mgNaOH), iodine value (120 mgI2/100g), saponification value (180 mgKOH/g), antiradical activity (46%), peroxide value (7.5 mEqO2/Kg), induction period (6.2 h), fatty acid: palmitic acid (13.1%), stearic acid (9.5 %), oleic acid (15.2 %) and linoleic acid (61.3%). Straight non food vegetable oils can offer a solution to fossil fuels by a cleaner burning with minimal adaptation of the engine. A single cylinder air cooled diesel engine Ruggerini RY 50 was used to measure emissions of various blends of watermelon oil (WO) and diesel fuel (WO10D90, WO20D80, WO30D70 and WO75D25). The physic-chemical properties of the oil influence the combustion process and emissions leading to the reduction of NOX and the increase in CO, CO2 and HC.


Metabolites ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 322
Author(s):  
Jae-Eun Song ◽  
Tiago C. Alves ◽  
Bernardo Stutz ◽  
Matija Šestan-Peša ◽  
Nicole Kilian ◽  
...  

In the presence of high abundance of exogenous fatty acids, cells either store fatty acids in lipid droplets or oxidize them in mitochondria. In this study, we aimed to explore a novel and direct role of mitochondrial fission in lipid homeostasis in HeLa cells. We observed the association between mitochondrial morphology and lipid droplet accumulation in response to high exogenous fatty acids. We inhibited mitochondrial fission by silencing dynamin-related protein 1(DRP1) and observed the shift in fatty acid storage-usage balance. Inhibition of mitochondrial fission resulted in an increase in fatty acid content of lipid droplets and a decrease in mitochondrial fatty acid oxidation. Next, we overexpressed carnitine palmitoyltransferase-1 (CPT1), a key mitochondrial protein in fatty acid oxidation, to further examine the relationship between mitochondrial fatty acid usage and mitochondrial morphology. Mitochondrial fission plays a role in distributing exogenous fatty acids. CPT1A controlled the respiratory rate of mitochondrial fatty acid oxidation but did not cause a shift in the distribution of fatty acids between mitochondria and lipid droplets. Our data reveals a novel function for mitochondrial fission in balancing exogenous fatty acids between usage and storage, assigning a role for mitochondrial dynamics in control of intracellular fuel utilization and partitioning.


2013 ◽  
Vol 305 (2) ◽  
pp. E205-E212 ◽  
Author(s):  
Francisco Visiedo ◽  
Fernando Bugatto ◽  
Viviana Sánchez ◽  
Irene Cózar-Castellano ◽  
Jose L. Bartha ◽  
...  

Placentas of women with gestational diabetes mellitus (GDM) exhibit an altered lipid metabolism. The mechanism by which GDM is linked to alterations in placental lipid metabolism remains obscure. We hypothesized that high glucose levels reduce mitochondrial fatty acid oxidation (FAO) and increase triglyceride accumulation in human placenta. To test this hypothesis, we measured FAO, fatty acid esterification, de novo fatty acid synthesis, triglyceride levels, and carnitine palmitoyltransferase activities (CPT) in placental explants of women with GDM or no pregnancy complication. In women with GDM, FAO was reduced by ∼30% without change in mitochondrial content, and triglyceride content was threefold higher than in the control group. Likewise, in placental explants of women with no complications, high glucose levels reduced FAO by ∼20%, and esterification increased linearly with increasing fatty acid concentrations. However, de novo fatty acid synthesis remained unchanged between high and low glucose levels. In addition, high glucose levels increased triglyceride content approximately twofold compared with low glucose levels. Furthermore, etomoxir-mediated inhibition of FAO enhanced esterification capacity by ∼40% and elevated triglyceride content 1.5-fold in placental explants of women, with no complications. Finally, high glucose levels reduced CPT I activity by ∼70% and phosphorylation levels of acetyl-CoA carboxylase by ∼25% in placental explants of women, with no complications. We reveal an unrecognized regulatory mechanism on placental fatty acid metabolism by which high glucose levels reduce mitochondrial FAO through inhibition of CPT I, shifting flux of fatty acids away from oxidation toward the esterification pathway, leading to accumulation of placental triglycerides.


2015 ◽  
Vol 308 (11) ◽  
pp. E960-E970 ◽  
Author(s):  
Ruth C. R. Meex ◽  
Andrew J. Hoy ◽  
Rachael M. Mason ◽  
Sheree D. Martin ◽  
Sean L. McGee ◽  
...  

Emerging evidence indicates that skeletal muscle lipid droplets are an important control point for intracellular lipid homeostasis and that regulating fatty acid fluxes from lipid droplets might influence mitochondrial capacity. We used pharmacological blockers of the major triglyceride lipases, adipose triglyceride lipase (ATGL) and hormone-sensitive lipase, to show that a large proportion of the fatty acids that are transported into myotubes are trafficked through the intramyocellular triglyceride pool. We next tested whether increasing lipolysis from intramyocellular lipid droplets could activate transcriptional responses to enhance mitochondrial and fatty acid oxidative capacity. ATGL was overexpressed by adenoviral and adenoassociated viral infection in C2C12 myotubes and the tibialis anterior muscle of C57Bl/6 mice, respectively. ATGL overexpression in C2C12 myotubes increased lipolysis, which was associated with increased peroxisome proliferator-activated receptor (PPAR)-∂ activity, transcriptional upregulation of some PPAR∂ target genes, and enhanced mitochondrial capacity. The transcriptional responses were specific to ATGL actions and not a generalized increase in fatty acid flux in the myotubes. Marked ATGL overexpression (20-fold) induced modest molecular changes in the skeletal muscle of mice, but these effects were not sufficient to alter fatty acid oxidation. Together, these data demonstrate the importance of lipid droplets for myocellular fatty acid trafficking and the capacity to modulate mitochondrial capacity by enhancing lipid droplet lipolysis in vitro; however, this adaptive program is of minor importance when superimposing the normal metabolic stresses encountered in free-moving animals.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Charlotte H. Hulme ◽  
Anna Nicolaou ◽  
Sharon A. Murphy ◽  
Alexander E. P. Heazell ◽  
Jenny E. Myers ◽  
...  

Abstract Diabetes mellitus (DM) during pregnancy can result in fetal overgrowth, likely due to placental dysfunction, which has health consequences for the infant. Here we test our prediction from previous work using a placental cell line that high glucose concentrations affect placental lipid metabolism. Placentas from women with type 1 (n = 13), type 2 (n = 6) or gestational (n = 12) DM, BMI-matched to mothers without DM (n = 18), were analysed for lipase and fatty acid transport proteins and fatty acid and triglyceride content. Explants from uncomplicated pregnancies (n = 6) cultured in physiological or high glucose were similarly analysed. High glucose levels did not alter placental lipase or transporter expression or the profile and abundance of fatty acids, but triglyceride levels were higher (p < 0.05), suggesting reduced β- oxidation. DM did not affect placental protein expression or fatty acid profile. Triglyceride levels of placentas from mothers with pre-existing DM were similar to controls, but higher in obese women with gestational DM. Maternal hyperglycemia may not affect placental fatty acid uptake and transport. However, placental β-oxidation is affected by high glucose and reduced in a subset of women with DM. Abnormal placental lipid metabolism could contribute to increased maternal-fetal lipid transfer and excess fetal growth in some DM pregnancies.


2018 ◽  
Vol 15 (30) ◽  
pp. 447-462
Author(s):  
M. C. de M. SOUZA ◽  
L. DI SOUZA ◽  
V. P. da S. Caldeira ◽  
A. G. D. SANTOS ◽  
B. ADILSON

With the increasing selective energy demand, fossil fuels are becoming scarce and environmentally incorrect, a viable alternative to this problem being the production of biodiesel. However, the esterification and transesterification reactions used are slow, expensive and ecologically incorrect because they produce polluting waste. Thus, it is necessary to develop techniques, reagents and equipment that make them fast, cheap and environmentally friendly. This work evaluated the performance of the thermal heating, microwave and ultrasonic methods in the esterification efficiency of oleic and stearic fatty acids via homogeneous acid catalysis. The efficiency of the reaction was certificated with the variables: time, yield and conversion and the biodiesel characterization were done with TG / DTG, FTIR and NMR. Conversions were determined by TG and 1H NMR and the yield by gravimetry. The results showed conversion with all methods with differences in the analyzed variables. The yields decrease in the microwave order (52%) conduction (33%) ultrasound (30%) for reactions with oleic acid and are practically the same (22, 22 and 20), independently of the stearic acid. Among the methods used, the most efficient is the microwave, because it has a higher yield in the case of oleic acid and reducing the reaction time.


1986 ◽  
Vol 251 (1) ◽  
pp. R137-R142 ◽  
Author(s):  
H. B. John-Alder ◽  
R. M. McAllister ◽  
R. L. Terjung

The functional significance of gluconeogenesis in prolonging endurance during submaximal activity was assessed in untrained and endurance-trained rats. Gluconeogenesis was inhibited at the phosphoenolpyruvate carboxykinase reaction by 3-mercaptopicolinic acid (3-MPA). Endurance was significantly reduced by 3-MPA in untrained (-32%; P less than 0.005) and in trained rats (-26%; P less than 0.001). Metabolic correlates of fatigue were examined in trained rats. At exhaustion, 3-MPA-treated rats had only 3% of resting hepatic glycogen, 46% of resting white quadriceps glycogen, and 37% of resting blood glucose. All of these substrates were at higher levels in sham-injected controls after the same duration of running (130 min). Glycogen levels in red quadriceps, blood lactate levels, and blood glycerol levels were not different between groups. Plasma free fatty acid levels were elevated to the same extent in both groups after 90 min of activity, remained high at 130 min in controls, but had returned to resting levels in the severely hypoglycemic 3-MPA-treated rats at exhaustion. The results indicate that gluconeogenesis is important for maintaining blood glucose levels and for prolonging endurance time during submaximal activity.


2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Iwona Gientka ◽  
Marek Kieliszek ◽  
Karolina Jermacz ◽  
Stanisław Błażejak

The search for efficient oleaginous microorganisms, which can be an alternative to fossil fuels and biofuels obtained from oilseed crops, has been going on for many years. The suitability of microorganisms in this regard is determined by their ability to biosynthesize lipids with preferred fatty acid profile along with the concurrent utilization of energy-rich industrial waste. In this study, we isolated, characterized, and identified kefir yeast strains using molecular biology techniques. The yeast isolates identified wereCandida inconspicua,Debaryomyces hansenii,Kluyveromyces marxianus,Kazachstania unispora, andZygotorulaspora florentina. We showed that deproteinated potato wastewater, a starch processing industry waste, supplemented with various carbon sources, including lactose and glycerol, is a suitable medium for the growth of yeast, which allows an accumulation of over 20% of lipid substances in its cells. Fatty acid composition primarily depended on the yeast strain and the carbon source used, and, based on our results, most of the strains met the criteria required for the production of biodiesel. In particular, this concerns a significant share of saturated fatty acids, such as C16:0 and C18:0, and unsaturated fatty acids, such as C18:1 and C18:2. The highest efficiency in lipid biosynthesis exceeded 6.3 g L−1.Kazachstania unisporawas able to accumulate the high amount of palmitoleic acid.


1994 ◽  
Vol 266 (3) ◽  
pp. G372-G381 ◽  
Author(s):  
M. Armand ◽  
P. Borel ◽  
C. Dubois ◽  
M. Senft ◽  
J. Peyrot ◽  
...  

Fasting subjects were intragastrically intubated and received a coarsely emulsified test meal. Gastric aspirates were collected after 1, 2, 3, and 4 h. During digestion in the stomach, unemulsified lipids (> or = 100 microns) represented a minor fraction. A significant amount of the large 70- to 100-microns lipid droplets disappeared, and fine 1- to 10-microns droplets were generated. The median lipid droplet diameter significantly decreased (21.9 vs. 52.9 microns) after 1 h and kept intermediate values for longer periods of time. The emulsion surface area was 100-120 m2/l and was basically provided by 1- to 100-microns droplets. Lipolysis catalyzed by gastric lipase primarily occurred within the first hour of digestion (11.9%). Smaller droplets were enriched in triglyceride lipolytic products. The free fatty acid concentrations were in the range of 5.6-8.2 mM over 1-4 h. The present finding demonstrates for the first time that in the human stomach most dietary lipids are present in the form of emulsified droplets, in the range of 20-40 microns, and that gastric lipolysis can help to increase emulsification in the stomach.


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