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In this paper, we study the T30923 antiproliferative potential and the contribution of its loop residues in six different human cancer cell lines by preparing five T30923 variants using the single residue replacement approach of loop thymidine with an abasic site mimic (S). G-rich oligonucleotides (GRO) show interesting anticancer properties because of their capability to adopt G-quadruplex structures (G4s), such as the G4 HIV-1 integrase inhibitor T30923. Considering the multi-targeted effects of G4-aptamers and the limited number of cancer cell lines tested, particularly for T30923, it should be important to find a suitable tumor line, in addition to considering that the effects also strictly depend on G4s. CD, NMR and non-denaturating polyacrylamide gel electrophoresis data clearly show that all modified ODNs closely resemble the dimeric structure of parallel G4s’ parent aptamer, keeping the resistance in biological environments substantially unchanged, as shown by nuclease stability assay. The antiproliferative effects of T30923 and its variants are tried in vitro by MTT assays, showing interesting cytotoxic activity, depending on time and dose, for all G4s, especially in MDA-MB-231 cells with a reduction in cell viability approximately up to 30%. Among all derivatives, QS12 results are the most promising, showing more pronounced cytotoxic effects both in MDA-MB-231 and Hela cells, with a decrease in cell viability from 70% to 60%. In summary, the single loop residue S substitution approach may be useful for designing antiproliferative G4s, considering that most of them, characterized by single residue loops, may be able to bind different targets in several cancer cell pathways. Generally, this approach could be of benefit by revealing some minimal functional structures, stimulating further studies aimed at the development of novel anticancer drugs.  相似文献   
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A DNA fragment of Saccharomyces cerevisiae with high homology to the acetyl-coenzyme A (acetyl-CoA) synthetase genes of Aspergillus nidulans and Neurospora crassa has been cloned, sequenced and mapped to chromosome I. It contains an open reading frame of 2139 nucleotides, encoding a predicted gene product of 79.2 kDa. In contrast to its ascomycete homologs, there are no introns in the coding sequence. The first ATG codon of the open reading frame is in an unusual context for a translational start site, while the next ATG, 24 codons downstream, is in a more conventional context. Possible implications of two alternative translational start sites for the cellular localization of the enzyme are discussed. A stable mutant of this gene, obtained by the gene disruption technique, had the same low basal activity of acetyl-CoA synthetase as wild-type cells when grown on glucose but completely lacked the strong increase in activity upon entering the stationary phase, providing direct proof that the gene encodes an inducible acetyl-CoA synthetase (ACS1) of yeast. As expected, the mutant was unable to grow on acetate as sole carbon source. Nevertheless, it showed normal induction of isocitrate lyase on acetate media, indicating that activity of acetyl-CoA synthetase is dispensable for induction of the glyoxylate cycle in S. cerevisiae. Surprisingly, disruption of the ACS1 gene did not affect growth on media containing ethanol as the sole carbon source, demonstrating that there are alternative pathways leading to acetyl-CoA under these conditions.  相似文献   
45.
Mammals along their early postnatal period develop a substantial amount of a very active brown adipose tissue (BAT). Through this work we explored the possibility that BAT may function as a long chain polyunsaturated fatty acids reservoir (LC-PUFA) during the rapid growth of brain structures. In new born rats 1, 6, 12 and 20 days old, we analyzed fatty acid percentage of triglycerides (TG) and phospholipid fractions, and the absolute amount of TG. In 6 day old rats we also evaluated the extend of further desaturation of 1-14C linoleic acid administered by intraperitoneal injection. Results demonstrated a drastic increase of TG concentration during experimental period (1,5; 40; 118; 120 mg/g wet weight) and LC-PUFA percentage was higher in "1 and 6" than "12 and 20" days old rats (16-17% vs 5%). Our results showed that BAT stored important amounts of LC-PUFA. On the other hand, 1-14C linoleic acid incorporation was higher in liver than BAT. In contrast, the desaturated products of 1-14C linoleic acid /1-14C linoleic acid ratio was greater in BAT than liver (>4). This could indicate that BAT synthesizes LC-PUFA in addition to store it. In summary we demonstrated than BAT is an important reservoir of LC-PUFA during postnatal brain growth.  相似文献   
46.
In order to expand the potential applications of G‐quadruplex structures, we explored the ability of heterochiral oligodeoxynucleotides based on the thrombin‐binding aptamer (TBA) sequence to fold into similar complexes, with particular focus on their resistance in biological environments. A combination of CD and NMR techniques was used. Similarly to TBA, the ODN ggTTggtgtggTTgg (lower case letters indicate L residues) is able to fold into a chair‐like antiparallel G‐quadruplex structure, but has a slightly higher thermal stability. The discovery that heterochiral ODNs are able to form stable G‐quadruplex structures opens up new possibilities for their development in several fields, as aptamers, sensors and, as recently shown, as catalysts for enantioselective reactions.  相似文献   
47.
A total of 287 olive lots and 161 olive oil samples were analyzed for fat content, moisture and free acidity, using a Fourier transform near‐infrared (FT‐NIR) instrument located in an industrial mill. Samples having a wide range of both reference values and olive lot sizes (from <0.5 to >4 t) were collected at three industrial mill plants, located in the same Italian region, which utilize different technological equipment for virgin olive oil production. Olive paste spectra were acquired in diffuse reflectance, while oil samples were measured in transmission. Calibration models for oil content and moisture of olives as well as free acidity of virgin olive oils were developed using partial least squares (PLS) regression, first derivative and straight line subtraction. Results of calibration and validation of the PLS models selected were good. The PLS results indicate good similarity between data obtained from FT‐NIR and reference laboratory methods, allowing a rapid and less expensive screening analysis. Unfortunately, the correlation between the oil yield values recorded for all olive lots at the industrial mills and the oil content predicted by FT‐NIR was not satisfactory (R2 = 0.605).  相似文献   
48.
Finger or heel‐pricked blood sampling for fatty acid analysis is suitable especially in newborn infants where blood sampling is difficult and phlebotomy for research can be unethical. The aim of this study was to evaluate dried blood long chain polyunsaturated fatty acids (LC‐PUFA) stability during storage at ?28 °C. We collected 12 blood cord samples that were analyzed immediately after blood drawing, with and without drying the blood on filter paper. Dried samples were then analyzed 7 days and 1, 3, and 6 months after collection. Butylated hydroxytoluene was added to all samples. Fatty acid composition and 13C enrichment were measured by gas chromatography and by gas chromatography‐isotope ratio mass spectrometry, respectively. The fatty acid composition, expressed in mol%, of the major LC‐PUFA at day 7 was not statistically different from time 0, however lower values were found by the first month of storage. The 13C enrichment of 20:4n‐6 and 22:6n‐3 did not differ during the whole study period. LC‐PUFA analysis from dried umbilical cord blood in neonates should be performed within a week, major losses of LC‐PUFA occur afterwards. However, fatty acids obtained from dried blood maintain their 13C enrichment value for up to 6 months and thus these samples are suitable for natural abundance isotopic studies.  相似文献   
49.
Verocytotoxin-producing Escherichia coli (VTEC) O26 is an emergent pathotype that has caused an increasing number of sporadic cases and outbreaks of gastroenteritis, hemorrhagic colitis, and hemolytic uremic syndrome in the United States and Europe. Many cases are associated with the consumption of milk and undercooked or fermented meats. The stx(2) strains of VTEC O26 seem to be more likely to cause human infections than isolates expressing only stx(1). The isolation and identification of VTEC O26 from foods is labor intensive and time-consuming. We developed a multiplex PCR (M-PCR) assay for the identification and characterization of E. coli O26 VTEC and its detection in raw milk and ground beef. The method is based on the amplification of the wzx, stx(1), and stx(2) genes for the simultaneous detection of the O26 antigen and verocytotoxin types 1 and 2. This M-PCR assay had a sensitivity of 10(8) CFU/ml when applied to a bacterial suspension and of 10(6) CFU/ml or g when applied to both inoculated milk and minced beef samples. This M-PCR assay also was highly specific, and results were consistently negative for negative controls (nonpathogenic E. coli strains, uninoculated milk and beef samples, and samples inoculated with the nontarget microorganisms). This method could be used for the rapid detection of E. coli O26 VTEC from foods and for the rapid identification and characterization of clinical and environmental isolates.  相似文献   
50.
Direct laser writing methods based on two‐photon polymerization (2PP) are powerful tools for the on‐demand printing of precise and complex 3D architectures at the micro and nanometer scale. While much progress was made to increase the resolution and the feature size throughout the years, by carefully designing a material, one can confer specific functional properties to the printed structures thus making them appealing for peculiar and novel applications. This Review summarizes the state‐of‐the‐art of functional resins and photoresists used in 2PP, discussing both the range of material functions available and the methods used to prepare them, highlighting advantages and disadvantages of different classes of materials in achieving certain properties.  相似文献   
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