Chemical Synthesis of Secondary Metabolites - …
Synthesis of secondary metabolites Nicotine
We next investigated which metabolites were most concentrated in the EVs. In order to get an approximation of the intra-EV concentration range, we calculated the concentrations of the metabolites in the EVs by dividing the mole amount of metabolites with the total EV volumes in the samples (Table ). The total volume of EVs ranged between 60-830 nl within the uEV preparations and was 372 nl in the pEVs. These calculations indicated that the intra-EV concentrations of the metabolites varied from sub micromolar up to > 10 mM in both uEVs and pEVs (Table ). EVs from both sources were rich in D-Ribose 5-phosphate, the most abundant metabolite in pEVs and 3rd most abundant in uEVs, and other metabolites involved in nucleotide metabolism in mostly > 10 µM to mM range. Amino acid ornithine, with the highest concentration of metabolites in the uEVs and 15th highest in pEVs, and several other members of the urea cycle were present in > 50 µM to mM concentrations in the EVs. Ornithine serves also as a precursor for the biosynthesis of spermidine, a multifunctional polyamine that stabilizes nucleic acids and membranes, present in > 10 µM quantities in both EV types. In conclusion, our data indicated that the metabolite profiles of EVs from different sources contained similarities, but also distinct differences. The EVs carried a subset of metabolites from several pathways, with high intra-EV concentrations of some specific metabolites.
Some of our tested normalization factors such as CD9 optical density [, ] and choline concentration have been shown to increase in Pca. However, it is difficult to find a normalization factor that would not be affected by the changed metabolism in cancer or in other physiological conditions. From a different point of view, a ratio of decreasing and increasing parameters in cancer could be employed to detect changes in a more sensitive way than normalization to a stable parameter. Here, patient HUB.3, who had an aggressive cancer, had still high PSA in plasma after the prostatectomy, whereas our normalized uEV biomarker candidates returned towards the control level. This may be explained by the different amounts of primary tumor or metastatic site -derived material remaining in the blood and urine after prostatectomy. On the other hand, when normalized to uEV-parameters, the levels of D-ribose 5-phosphate and adenosine showed a relatively minor difference between the pre- and post-prostatectomy uEV samples of HUB.3 (Fig. A). Since these metabolites were generally present in high concentrations in the EVs and thus amenable to measurement from low sample amounts, one focus area of future Pca EV biomarker research could be the nucleic acid, particularly the purine pathway, metabolites.
Biosynthesis of plant secondary metabolites - …
The metabolic changes typical for Pca could explain the low levels of the metabolites in the pre-prostatectomy uEVs. First, glucuronate, with the largest difference between the pre- and post-prostatectomy or healthy control samples, contributes to the pentose phosphate pathway necessary for nucleic acid synthesis. Since cancer cells have a higher demand for nucleic acids than normal cells, the increased usage could lead to reduced concentration of glucuronate in the EVs. In support, D-ribose 5-phosphate and adenosine from the purine pathway, were also low in the pre-prostatectomy uEV samples. Alternatively, less free glucuronate may be present in the cancer samples due to its heavy incorporation into proteoglycans, such as hyaluronan, or to toxic/waste substances in the detox metabolism through glucuronidation. Remarkably, it has been shown that hyaluronan synthesis is increased in Pca, promoting spontaneous metastasis  and also coating cancer-derived EVs .
Since more specific Pca biomarkers are needed to replace PSA and biopsies for non-invasive detection/monitoring of clinically significant Pca , another part of our study focused on developing methods for EV sample preparation and data normalization that are suitable for EV metabolomics and future biomarker discovery. In our experiments, as little as 9 x 109 EVs or EVs from 10 ml of urine were enough to obtain a metabolite profile with the high-sensitivity targeted UPLC-MS-MS platform. In addition, our EV isolation protocol was able to remove several urine-derived soluble metabolites. For data normalization, we conducted an initial proof-of-concept study of Pca-derived changes in the uEV metabolite profiles. Normalization of the metabolomics data to the EV-derived parameters or by the ratio of metabolites led to the identification of metabolites with low levels in the pre-prostatectomy uEV samples. In contrast, traditional normalization parameters, creatinine and urine volume, did not reveal any systematic difference. Furthermore, the differences obtained with the uEV data were greater and different than the ones observed from the conventional analysis of the matched urine samples indicating the potential of EV-derived metabolomics for biomarker discovery. Future efforts could employ these techniques for EV biomarker discovery with a wider or more focused panel of metabolites and a higher number of patients.
Pesticide applicators are exposed primarily to -DDT, whereas nearly all of the general population is exposed to the -DDE metabolite in the diet or drinking-water (Longnecker et al., 1997). Levels of exposure and the concentrations of DDT in human tissues, milk, and blood have been summarized by Ahlborg et al. (1995). The IARC (1991) and Smith (1999) reported that the mean concentrations of DDT in the population have declined in much of the world: from 5000–10 000 µg/kg to around 1000 µg/kg of milk fat or even lower over the last three decades. Although different means are found in different regions, the declines seen in various countries correspond to their restrictions on use of DDT.
In conclusion, to our knowledge this is the first study of small polar metabolites from urine and platelet-derived EVs, which provides insights into the amounts of required material, the enriched metabolites and their cellular origin as well as data normalization procedures. We also obtained a core profile of metabolites from EVs against which differing metabolites from various EV types can be compared. Finally, this study provided leads to the changes in the metabolite profiles of EVs associated with Pca. Our study can serve as a basis for further studies of EV metabolites in different body fluids or in a larger group of Pca patients. Together, our findings suggest that EV metabolomics could offer a new non-invasive and high-throughput tool to monitor Pca or other diseases.
Chemical Synthesis of Secondary Metabolites | …
Chemical Synthesis of Secondary Metabolites
Keywords: extracellular vesicles, exosomes, metabolomics, urine, platelets, prostate cancer
Secondary Metabolism Flashcards | Quizlet
(f) Studies of metabolites
Start studying Secondary Metabolism
14. Lane AN, Fan TW. Regulation of mammalian nucleotide metabolism and biosynthesis. 2015;43(4):2466-2485
are known as secondary metabolites.
In addition to the uEV metabolomics, we assessed Pca-related changes in the matching urine samples. Changes in the pre-prostatectomy urine samples were different from those detected from the uEVs. When normalized to the urine creatinine content (measured from unpurified urine), glycine, histidine, proline and aminoisobutyric acid were lower in the pre-prostatectomy samples as compared to the combined group of control and post-prostatectomy samples (2.5-3.2 x, p
Secondary metabolite - Wikipedia
In contrast to the EV-derived factor and ratio normalizations, normalization to urine volume or creatinine did not produce any systematic differences that would distinguish the pre-prostatectomy uEV samples from the other study groups (data not shown). Our data thus suggests that normalization to EV-derived parameters or analysis of metabolite ratios would have the best potential to reveal cancer-related alterations in the EV metabolite profiles.
Secondary Metabolites | Phenols | Metabolism
Most significant changes in the urinary EV metabolites in prostate cancer. A. Metabolite concentrations in the individual urinary EV samples were normalized to the CD9 optical density (OD) determined by western blotting, an EV-derived parameter. The analysis indicated lower levels of four metabolites in the pre-prostatectomy samples (pre) in comparison to post-prostatectomy (post) and healthy control samples. Pre- and post-prostatectomy samples from the same patients (HUB. 1-3) are connected with lines. B. Ratios between two metabolites indicated lower levels of glucuronate, isobutyryl-L-carnitine and D-ribose 5-phosphate in the pre-prostatectomy samples as in A, but also changes in other metabolites. Statistical significance is indicated for the comparisons of pre-prostatectomy group to control and post-prostatectomy groups separately (small brackets) or to the combined control and post-prostatectomy group (large brackets). p
Interfere with herbivore protein synthesis
Metabolomic analysis of EVs is a new field of research that holds potential to reveal the status of cellular metabolism in a non-invasive way. It could unravel biomarkers for various diseases on its own or complement current assays of proteins and nucleic acids within EVs. Our work on the metabolite profiles of urinary and platelet EVs offers several new insights into EV contents and technical aspects of profiling the EVs for future biomarker research.
"I have always been impressed by the quick turnaround and your thoroughness. Easily the most professional essay writing service on the web."
"Your assistance and the first class service is much appreciated. My essay reads so well and without your help I'm sure I would have been marked down again on grammar and syntax."
"Thanks again for your excellent work with my assignments. No doubts you're true experts at what you do and very approachable."
"Very professional, cheap and friendly service. Thanks for writing two important essays for me, I wouldn't have written it myself because of the tight deadline."
"Thanks for your cautious eye, attention to detail and overall superb service. Thanks to you, now I am confident that I can submit my term paper on time."
"Thank you for the GREAT work you have done. Just wanted to tell that I'm very happy with my essay and will get back with more assignments soon."