Ascorbate increases the synthesis of procollagen hydroxyproline by cultured fibroblasts from chick embryo tendons without activation of prolyl hydroxyla.

An improved procedure was developed to extract prolyl hydroxylase from tendon cells of chick embryos with detergent, and improved assays were developed for both the activity of the enzyme and the amount of enzyme protein. Freshly isolated tendon cells were found to contain approx. 100 mug of enzyme protein per 10(8) cells and 40-50% of the enzyme protein was active. When the cells were cultured, they were found to contain the same amount of enzyme protein but only 15-20% of the enzyme protein was active. Gel filtration of cell extracts indicated that the active form of prolyl hydroxylase in freshly isolated tendon cells and incultured tendon cells had the same apparent size and the same activity per mug of immunoreactive protein as enzyme which was shown to be a tetramer. The inactive form was found to have about the same apparent size as subunits of the enzyme. When freshly isolated cells were incubated for 2 h in the presence of 40 mug per ml of ascorbate, there was a slight increase in the rate of hydroxyproline synthesis. In cultured cells, ascorbate at a concentration of 40 mug per ml caused a 2-fold increase in the rate of hydroxyproline synthesis within 30 min. However, ascorbate did not icrease the activity of prolyl hydroxylase in extracts from either cell system. Therefore it appears that the influence of ascorbate on synthesis of procollagen hydroxyproline by the cells studied here must be ascribed to a cofactor effect on the hydroxylation reaction similar to that observed with purified enzyme, and it does not involve "activation" of inactive enzyme protein to active enzyme as has been observed in cultures of L-929 and 3T6 mouse fibroblasts.     

Effects of hypophysectomy, growth hormone, and thyroxine on protein turnover in heart.

Cardiac atrophy following hypophysectomy was accompanied by decreased heart content of RNA and polysomes and increased levels of ribosomal subunits, suggesting that protein synthesis was restricted by a reduced supply of ribosomes and an imbalance between rates of peptide-chain initiation and elongation. During perfusion in vitro, provision of palmitate restored the normal balance between rates of initiation and elongation but protein synthesis was lower in hearts of hypophysectomized than normal rats, reflecting the lower RNA content of hearts from hormone-deficient animals. After the period of atrophy had passed, or after treatment with growth hormone and thyroxine, heart RNA content and rates of protein synthesis were equal to or greater than those found in normal hearts. When plasma levels of amino acids, glucose, fatty acids, and insulin, and rates of beating and ventricular pressure development observed in normal and hypophysectomized rats were simulated during in vitro perfusion, hearts from hormone-deficient rats had reduced rates of protein synthesis but unaltered rates of degradation. Cathepsin D activity in heart homogenates (+ Triton X-100) was elevated during cardiac atrophy when expressed per g of tissue but not when expressed per heart.     

Ascorbate increases the synthesis of procollagen hydroxyproline by cultured fibroblasts from chick embryo tendons without activation or prolyl hydroxylase

An improved procedure was developed to extract prolyl hydroxylase from tendon cells of chick embryos with detergent, and improved assays were developed for both the activity of the enzyme and the amount of enzyme protein. Freshly isolated tendon cells were found to contain approx. 100 μg of enzyme protein per 10⁸ cells and 40–50% of the enzyme protein was active. When the cells were cultured, they were found to contain the same amount of enzyme protein by only 15–20% of the enzyme protein was active. Gel filtration of cell extracts indicated that the active form of prolyl hydroxylase in freshly isolated tendon cells and in cultured tendon cells had the same apparent size and the same activity per μg of immunoreactive protein as enzyme which was shown to be a tetramer. The inactive form was found to have about the same apparent size as subunits of the enzyme.When freshly isolated cells were incubated for 2 h in the presence of 40 μg per ml of ascorbate, there was a slight increase in the rate of hydroxyproline synthesis. In cultured cells, ascorbate at a concentration of 40 μg per ml caused a 2-fold increase in the rate of hydroxyproline synthesis within 30 min. However, ascorbate did not increase the activity of prolyl hydroxylase in extracts from either cell system. Therefore it appears that the influence of ascorbate on synthesis of procollagen hydroxyproline by the cells studied here must be ascribed to a cofactor effect on the hydroxylation reaction similar to that observed with purified enzyme, and it does not involve “activation” of inactive enzyme protein to active enzyme as has been observed in cultures of L-929 and 3T6 mouse fibroblasts.     

Effect of ellagic and caffeic acids on covalent binding of benzo[a]pyrene to epidermal DNA of mouse skin in organ culture

The covalent binding of the anti-diol epoxide of benzo[a]pyrene to cellular DNA of mouse skin in organ culture is affected by the presence of ellagic acid in the culture medium. At 10(-4) M, BaPDE /DNA formation is 40% less than that observed when no ellagic acid is present. Caffeic acid, a similar plant phenolic compound, demonstrates no inhibitory effect on BaPDE /formation. The plant phenolic acids do not drastically interfere with the metabolism of benzo[a]pyrene as shown by the BaP-metabolite profiles of the skin or of the culture medium.     

The Association between Genetic Polymorphism and the Processing Efficiency of miR-149 Affects the Prognosis of Patients with Head and Neck Squamous Cell Carcinoma

MicroRNAs (miRNAs) play important roles in modulating the neoplastic process of cancers including head and neck squamous cell carcinoma (HNSCC). A genetic polymorphism (rs2292832, C>T) has been recently identified in the precursor of miR-149; nevertheless its clinicopathological implications remain obscure. In this study, we showed that miR-149 is down-regulated in HNSCC compared to normal mucosa and this is associated with a poorer patient survival. In addition, HNSCC patients with the T/T genotype have more advanced tumors and a worse prognosis. Multivariate analysis indicated that patients carried the T/T genotype have a 2.81-fold (95% CI: 1.58–4.97) increased risk of nodal metastasis and 1.66-fold (95% CI: 1.05–2.60) increased risk of mortality compared to other groups. T/T genotype also predicted the worse prognosis of buccal mucosa carcinoma subset of HNSCC. In vitro analysis indicated that exogenous miR-149 expression reduces the migration of HNSCC cells. Moreover, HNSCC cell subclones carrying the pri-mir-149 sequence containing the T variant show a low processing efficacy when converting the pre-mir-149 to mature miR-149. These findings suggest that miR-149 suppresses tumor cell mobility, and that the pre-mir-149 polymorphism may affect the processing of miR-149, resulting in a change in the abundance of the mature form miRNA, which, in turn, modulates tumor progression and patient survival.     

Enabling Deformable and Stretchable Batteries

Deformable energy storage devices are needed to power next‐generation wearable electronics that interface intimately with human skin. Currently, deformable energy storage devices demonstrate poor performance compared to their rigid lithium‐ion counterparts, forcing wearable manufacturers to design their devices around bulky battery compartments. However, technological advances to create deformable batteries at the component and device level have yielded continuous improvement in stretchable batteries over the last five years. In this Essay, the major strategies at the component and device level that have been successfully employed to create stretchable batteries are reviewed. The outstanding challenges facing deformable energy storage are also discussed, namely, energy density, packaging, delamination, device integration, and manufacturing. This Essay will give researchers who are interested in contributing to the development of deformable batteries a cursory understanding of the most successful strategies to date, and provide insights into the most important directions to pursue in the future.     

Aging shifts mitochondrial dynamics toward fission to promote germline stem cell loss

Changes in mitochondrial dynamics (fusion and fission) are known to occur during stem cell differentiation; however, the role of this phenomenon in tissue aging remains unclear. Here, we report that mitochondrial dynamics are shifted toward fission during aging of Drosophila ovarian germline stem cells (GSCs), and this shift contributes to aging‐related GSC loss. We found that as GSCs age, mitochondrial fragmentation and expression of the mitochondrial fission regulator, Dynamin‐related protein (Drp1), are both increased, while mitochondrial membrane potential is reduced. Moreover, preventing mitochondrial fusion in GSCs results in highly fragmented depolarized mitochondria, decreased BMP stemness signaling, impaired fatty acid metabolism, and GSC loss. Conversely, forcing mitochondrial elongation promotes GSC attachment to the niche. Importantly, maintenance of aging GSCs can be enhanced by suppressing Drp1 expression to prevent mitochondrial fission or treating with rapamycin, which is known to promote autophagy via TOR inhibition. Overall, our results show that mitochondrial dynamics are altered during physiological aging, affecting stem cell homeostasis via coordinated changes in stemness signaling, niche contact, and cellular metabolism. Such effects may also be highly relevant to other stem cell types and aging‐induced tissue degeneration.     

Stool DNA test targeting methylated syndecan-2 (SDC2) as a noninvasive screening method for colorectal cancer

Despite the steadily increasing worldwide incidence of colorectal cancer (CRC), an effective noninvasive approach for early detection of CRC is still under investigation. The guaiac-based fecal occult blood test (FOBT) and fecal immunochemical test (FIT) have gained popularity as noninvasive CRC screening tests owing to their convenience and relatively low costs. However, the FOBT and FIT have limited sensitivity and specificity. To develop a noninvasive tool for the detection of CRC, we investigated the sensitivity, specificity, and accuracy of a stool DNA test targeting methylated syndecan-2 (SDC2), which is frequently methylated in patients with CRC. The present study enrolled 62 patients diagnosed as having stage 0-IV CRC and 76 healthy participants between July 2018 and June 2019 from two institutions. Approximately 4.5 g of stool sample was collected from each participant for detection of human methylated SDC2 gene. In total, 48 of 62 (77.4%) patients with CRC showed positive results, whereas 67 out of 76 (88.2%) healthy participants showed negative results. The area under the curve of the receiver operating characteristic curve constructed was 0.872 for discrimination between patients with CRC and healthy individuals. The present study highlights the potential of the fecal methylated SDC2 test as a noninvasive detection method for CRC screening with a relatively favorable sensitivity of 77.4%, a specificity of 88.2% and a positive predictive value of 84.2% compared with other available fecal tests. Further multicenter clinical trials comprising subjects of varied ethnicities are required to validate this test for the mass screening of patients with CRC.