Purification of prostaglandin E2-9-oxoreductase from human decidua vera

Prostaglandin E2-9- oxoreductase (PGE2-9-OR), the enzyme which converts prostaglandin E2 (PGE2) to prostaglandin F2 alpha (PGF2 alpha), has been detected in human decidua vera. A 105-fold purification was achieved when the centrifuged homogenate was fractionated sequentially by DEAE-Trisacryl, hydroxyapatite-agarose gel, ultrogel AcA 44 and Matrex gel blue A gel chromatographies. The following kinetic constants for PGE2-9-OR have been obtained. The equilibrium constant with respect to PGE2 is 83 microM, the Michaelis constant, Km, for PGE2 is 80 microM, for NADPH 1.6 microM. The maximal velocity for the forward reaction is V1 = .203 pmol/min. The enzyme was inhibited by progesterone, oestradiol-17 beta, cortisol and pharmaceutical drugs. An activating effect could be demonstrated with Ca2+ and oxytocin. The occurrence of PGE2-9-OR in the decidua vera suggests that this enzyme may be responsible for the transformation of PGE2 to PGF2 alpha in these tissues. This may be an important mechanism for the initiation and maintenance of uterine contractions.     

The differential effects of the carcinogen dimethylnitrosamine on isocitrate and 6-phosphogluconate metabolism in single intact cells

A microspectrofluorimetric study is made of the influence of dimethylnitrosamine on NADP reduction, following sequential microinjections into the same L cell, of two substrates: (1) isocitrate, with activity of isocitrate dehydrogenase both in the extramitochondrial and intramitochondrial compartments, (2) 6-phosphogluconate, with activity of the dehydrogenase in the extramitochondrial compartment. In control L cells a two-step reduction of NAD(P) is obtained followed by relatively slow reoxidation. In the minutes which follow addition of carcinogen, e.g., dimethylnitrosamine, to the cell medium the isocitrate and 6-phosphogluconate-induced transient NADP reoxidation is decreased in magnitude compared to control, while the rate constant of NADPH reoxidation is considerably accelerated, possibly due to requirements at the level of the microsomal metabolizing system. Observations within the first hour of carcinogen addition suggest an interesting system for evaluating the immediate actions of carcinogens at extranuclear sites: i.e., a comparative study of NADP reduction-reoxidation rate constants via injection of substrates for extra- vs. intramitochondrial pathways.     

On the anatomical definition of arterial networks in blood flow simulations: comparison of detailed and simplified models

Biomechanics and Modeling in Mechanobiology - The goal of this work is to assess the impact of vascular anatomy definition degree in the predictions of blood flow models of the arterial network. To...     

Dehalogenation of 4-chlorobenzoate by 4-chlorobenzoate dehalogenase from pseudomonas sp. CBS3: an ATP/coenzyme A dependent reaction

Pseudomonas sp. CBS3 was grown with 4-chlorobenzoate as sole source of carbon and energy. Freshly prepared cell-free extracts converted 4-chlorobenzoate to 4-hydroxybenzoate. After storage for 16 hours at 25 degrees C only about 50% of the initial activity was left. Treatment at 55 degrees C for 10 minutes, dialysis or desalting of the extracts by gel filtration caused a total loss of the activity of the 4-chlorobenzoate dehalogenase. The activity could be restored by the addition of ATP, coenzyme A and Mg2+. If one of these cofactors was missing, no dehalogenating activity was detectable. The amount of 4-hydroxybenzoate formed was proportional to the amount of ATP available in the test system whereas CoA served as a real coenzyme. A novel ATP/coenzyme A dependent reaction mechanism for the dehalogenation of 4-chlorobenzoate by 4-chlorobenzoate dehalogenase from Pseudomonas sp. CBS3 is proposed.     

LncRNA Bmp1 promotes the healing of intestinal mucosal lesions via the miR-128-3p/PHF6/PI3K/AKT pathway

Intestinal mucosal injuries are directly or indirectly related to many common acute and chronic diseases. Long non-coding RNAs (lncRNAs) are expressed in many diseases, including intestinal mucosal injury. However, the relationship between lncRNAs and intestinal mucosal injury has not been determined. Here, we investigated the functions and mechanisms of action of lncRNA Bmp1 on damaged intestinal mucosa. We found that Bmp1 was increased in damaged intestinal mucosal tissue and Bmp1 overexpression was able to alleviate intestinal mucosal injury. Bmp1 overexpression was found to influence cell proliferation, colony formation, and migration in IEC-6 or HIEC-6 cells. Moreover, miR-128-3p was downregulated after Bmp1 overexpression, and upregulation of miR-128-3p reversed the effects of Bmp1 overexpression in IEC-6 cells. Phf6 was observed to be a target of miR-128-3p. Furthermore, PHF6 overexpression affected IEC-6 cells by activating PI3K/AKT signaling which was mediated by the miR-128-3p/PHF6 axis. In conclusion, Bmp1 was found to promote the expression of PHF6 through the sponge miR-128-3p, activating the PI3K/AKT signaling pathway to promote cell migration and proliferation.Subject terms: Cell growth, Cell migration     

Antioxidant effect of diethyldithiocarbamate on microsomal lipid peroxidation assessed by low-level chemiluminescence and alkane production

Different thiol-containing compounds, such as diethyldithiocarbamate (DDC), glutathione, penicillamine, and dithioerythritol have been chosen to study their effect on ascorbate/Fe-ADP-induced lipid peroxidation, detected by low-level chemiluminescence and alkane production. In the concentration range used, these thiols exerted a temporary protection against lipid peroxidation by lengthening the induction period; after overcoming this induction period, no substantial inhibition of either chemiluminescence or alkane production was observed. DDC was effective in protecting against lipid peroxidation in the nanomolar range, whereas the group of other thiol-containing molecules operated in the millimolar range.