scholarly journals Characterization of a Haematococcus pluvialis Diacylglycerol Acyltransferase 1 and Its Potential in Unsaturated Fatty Acid-Rich Triacylglycerol Production

2021 ◽  
Vol 12 ◽  
Author(s):  
Hongli Cui ◽  
Wenxin Xu ◽  
Xiaoli Zhu ◽  
Chunchao Zhao ◽  
Yulin Cui ◽  
...  
Keyword(s):  
Haematococcus Pluvialis ◽  
Diacylglycerol Acyltransferase ◽  
Fatty Acyl ◽  
Dual Function ◽  
High Accumulation ◽  
Oil Crops ◽  
Unicellular Green Alga ◽  
Heterogeneous Expression

The unicellular green alga Haematococcus pluvialis has been recognized as an industry strain to produce simultaneously esterified astaxanthin (EAST) and triacylglycerol (TAG) under stress induction. It is necessary to identify the key enzymes involving in synergistic accumulation of EAST and TAG in H. pluvialis. In this study, a novel diacylglycerol acyltransferase 1 was systematically characterized by in vivo and in silico assays. The upregulated expression of HpDGAT1 gene was positively associated with the significant increase of TAG and EAST contents under stress conditions. Functional complementation by overexpressing HpDGAT1 in a TAG-deficient yeast strain H1246 revealed that HpDGAT1 could restore TAG biosynthesis and exhibited a high substrate preference for monounsaturated fatty acyl-CoAs (MUFAs) and polyunsaturated fatty acyl-CoAs (PUFAs). Notably, heterogeneous expression of HpDGAT1 in Chlamydomonas reinhardtii and Arabidopsis thaliana resulted in a significant enhancement of total oils and concurrently a high accumulation of MUFAs- and PUFAs-rich TAGs. Furthermore, molecular docking analysis indicated that HpDGAT1 contained AST-binding sites. These findings evidence a possible dual-function role for HpDGAT1 involving in TAG and EAST synthesis, demonstrating that it is a potential target gene to enrich AST accumulation in this alga and to design oil production in both commercial algae and oil crops.

scholarly journals Effects of streptozotocin-diabetes and insulin administration in vivo or in vitro on the activities of five enzymes in the adipose-tissue triacylglycerol-synthesis pathway

1987 ◽  
Vol 243 (1) ◽  
pp. 289-292 ◽  
Author(s):  
E D Saggerson ◽  
C A Carpenter
Keyword(s):  
Insulin Treatment ◽  
Streptozotocin Diabetes ◽  
Diacylglycerol Acyltransferase ◽  
Fatty Acyl ◽  
Diabetic Rats ◽  
Insulin Administration ◽  
Triacylglycerol Synthesis ◽  
Phosphatidate Phosphohydrolase

At 2 days after administration of streptozotocin (100 mg/kg), activities in rat epididymal fat-pads of the following enzymes were significantly decreased: fatty acyl-CoA synthetase (FAS), mitochondrial and microsomal forms of glycerolphosphate acyltransferase (GPAT), monoacylglycerolphosphate acyltransferase (MGPAT) and Mg2+-dependent phosphatidate phosphohydrolase (PPH). There were no significant changes in diacylglycerol acyltransferase or Mg2+-independent PPH. Insulin administration to diabetic rats over 2 days restored activities of FAS, both forms of GPAT, MGPAT and Mg2+-dependent PPH. Significant restoration of all five activities was also seen 2 h after a single administration of insulin, but was not observed 45 min after insulin treatment. Insulin significantly increased all five enzyme activities when adipocytes from diabetic rats were incubated for 2 h with a mixture of glucose, lactate, pyruvate and amino acids.

scholarly journals Synthesis and Characterization of Radiogallium-Labeled Cationic Amphiphilic Peptides as Tumor Imaging Agents

Cancers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2388
Author(s):  
Takeshi Fuchigami ◽  
Takeshi Chiga ◽  
Sakura Yoshida ◽  
Makoto Oba ◽  
Yu Fukushima ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Tumor Imaging ◽  
Pharmacokinetic Profile ◽  
Kb Cells ◽  
High Accumulation ◽  
Amphiphilic Peptides ◽  
Amphiphilic Peptide ◽  
Low Levels

SVS-1 is a cationic amphiphilic peptide (CAP) that exhibits a preferential cytotoxicity towards cancer cells over normal cells. In this study, we developed radiogallium-labeled SVS-1 (67Ga-NOTA-KV6), as well as two SVS-1 derivatives, with the repeating KV residues replaced by RV or HV (67Ga-NOTA-RV6 and 67Ga-NOTA-HV6). All three peptides showed high accumulation in epidermoid carcinoma KB cells (53–143% uptake/mg protein). Though 67Ga-NOTA-RV6 showed the highest uptake among the three CAPs, its uptake in 3T3-L1 fibroblasts was just as high, indicating a low selectivity. In contrast, the uptake of 67Ga-NOTA-KV6 and 67Ga-NOTA-HV6 into 3T3-L1 cells was significantly lower than that in KB cells. An endocytosis inhibition study suggested that the three 67Ga-NOTA-CAPs follow distinct pathways for internalization. In the biodistribution study, the tumor uptakes were found to be 4.46%, 4.76%, and 3.18% injected dose/g of tissue (% ID/g) for 67Ga-NOTA-KV6, 67Ga-NOTA-RV6, and 67Ga-NOTA-HV6, respectively, 30 min after administration. Though the radioactivity of these peptides in tumor tissue decreased gradually, 67Ga-NOTA-KV6, 67Ga-NOTA-RV6, and 67Ga-NOTA-HV6 reached high tumor/blood ratios (7.7, 8.0, and 3.8, respectively) and tumor/muscle ratios (5.0, 3.3, and 4.0, respectively) 120 min after administration. 67Ga-NOTA-HV6 showed a lower tumor uptake than the two other tracers, but it exhibited very low levels of uptake into peripheral organs. Overall, the replacement of lysine in SVS-1 with other basic amino acids significantly influenced its binding and internalization into cancer cells, as well as its in vivo pharmacokinetic profile. The high accessibility of these peptides to tumors and their ability to target the surface membranes of cancer cells make radiolabeled CAPs excellent candidates for use in tumor theranostics.

Characterization of a Type‐2 Diacylglycerol Acyltransferase from Haematococcus pluvialis Reveals Possible Allostery of the Recombinant Enzyme

Lipids ◽  
2019 ◽  
Vol 55 (5) ◽  
pp. 425-433
Author(s):  
Trinh Nguyen ◽  
Yang Xu ◽  
Mona Abdel‐Hameed ◽  
John L. Sorensen ◽  
Stacy D. Singer ◽  
...  
Keyword(s):  
Haematococcus Pluvialis ◽  
Diacylglycerol Acyltransferase ◽  
Recombinant Enzyme

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

Comparison of Immunological and Functional Assays for Measurement of Soluble Fibrin

1995 ◽  
Vol 74 (02) ◽  
pp. 673-679 ◽  
Author(s):  
C E Dempfle ◽  
S A Pfitzner ◽  
M Dollman ◽  
K Huck ◽  
G Stehle ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Low Grade ◽  
Plasma Samples ◽  
Normal Range ◽  
Soluble Fibrin ◽  
Discriminating Power ◽  
Fibrin Monomer ◽  
Cerebral Ischemic

SummaryVarious assays have been developed for quantitation of soluble fibrin or fibrin monomer in clinical plasma samples, since this parameter directly reflects in vivo thrombin action on fibrinogen. Using plasma samples from healthy blood donors, patients with cerebral ischemic insult, patients with septicemia, and patients with venous thrombosis, we compared two immunologic tests using monoclonal antibodies against fibrin-specific neo-epitopes, and two functional tests based on the cofactor activity of soluble fibrin complexes in tPA-induced plasminogen activation. Test A (Enzymun®-Test FM) showed the best discriminating power among normal range and pathological samples. Test B (Fibrinostika® soluble fibrin) clearly separated normal range from pathological samples, but failed to discriminate among samples from patients with low grade coagulation activation in septicemia, and massive activation in venous thrombosis. Functional test C (Fibrin monomer test Behring) displayed good discriminating power between normal and pathological range samples, and correlated with test A (r = 0.61), whereas assay D (Coa-Set® Fibrin monomer) showed little discriminating power at values below 10 μg/ml and little correlation with other assays. Standardization of assays will require further characterization of analytes detected.

Insulinomimetic properties of trace elements and characterization of their in vivo mode of action

Diabetes ◽  
1990 ◽  
Vol 39 (10) ◽  
pp. 1243-1250 ◽  
Author(s):  
L. Rossetti ◽  
A. Giaccari ◽  
E. Klein-Robbenhaar ◽  
L. R. Vogel
Keyword(s):  
Trace Elements ◽  
Mode Of Action

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

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