Liver uricase in Camelus dromedarius: purification and properties

1. Uricase (urate: oxygen oxidoreductase, EC 1.7.3.3) was purified 750-fold from the liver of Camelus dromedarius. 2. The enzyme is a tetramer with a Mr of 100,000, displays high specificity for uric acid with a Km of 12 microM and is inhibited by a selected number of purine derivatives carrying oxygen at the C2 position. 3. The effect of pH and the inhibition by thiol compounds and chelating agents on the enzyme activity is reported. 4. Some lines of evidence suggesting the possibility of interaction of camel liver uricase with oligonucleotides are presented.     

The interaction of cyproheptadine with agents affecting neuromuscular transmission.

Using the rat phrenic nerve diaphragm, cyproheptadine at concentrations of 1 to 8 mug/ml did not affect or slightly augmented indirect muscle twitches, but potentiated blockade by tubocurarine, decamethonium and succinylcholine, and antagonized the augmentation of twitches by neostigmine. Ketamine, choline and tetraethylammonium at concentrations causing no blockade produced, when given after cyproheptadine (6 mug/ml), a high degree of blockade. At concentrations of 9 to 20 mug/ml, cyproheptadine induced neuromuscular blockade which was slow in onset, more apparent at higher rate of stimulation and was not reversed by neostigmine, choline or tetraethylammonium. In the cat tibialis anterior muscle, it potentiated blockade by tubocurarine, decamethonium and succinylcholine, and blocked acetylcholine twitches. In the chick biventer cervicis muscle, the durg was more effective in blocking indirect twitches than responses to carbachol.     

Reptin regulates insulin‐stimulated Akt phosphorylation in hepatocellular carcinoma via the regulation of SHP‐1/PTPN6

Hepatocellular carcinoma (HCC) is the main primary cancer of the liver. Many studies have shown that insulin resistance is a risk factor for HCC. We previously discovered the overexpression and oncogenic role of the Reptin/RUVBL2 ATPase in HCC. Here, we found that Reptin silencing enhanced insulin sensitivity in 2 HCC cell lines, as shown by a large potentiation of insulin‐induced AKT phosphorylation on Ser473 and Thr308, and of downstream signalling. Reptin silencing did not affect the tyrosine phosphorylation of the insulin receptor nor of IRS1, but it enhanced the tyrosine phosphorylation of the p85 subunit of PI3K. The expression of the SHP‐1/PTPN6 phosphatase, which dephosphorylates p85, was reduced after Reptin depletion. Forced expression of SHP‐1 restored a normal AKT phosphorylation after insulin treatment in cells where Reptin was silenced, demonstrating that the downregulation of SHP1 is mechanistically linked to increased Akt phosphorylation. In conclusion, we have uncovered a new function for Reptin in regulating insulin signalling in HCC cells via the regulation of SHP‐1 expression. We suggest that the regulation of insulin sensitivity by Reptin contributes to its oncogenic action in the liver.     

Wuxal amino (Bio stimulant) improved growth and physiological performance of tomato plants under salinity stress through adaptive mechanisms and antioxidant potential

In the present study, ameliorative capabilities of wuxal amino (bio stimulant) under salt stress has been investigated through adaptive mechanisms and antioxidant potential in tomato plants. In the experiment, two different concentrations (2 cm L^-1 and 3 cm L^-1) of wuxal amino through foliar application and soil irrigation were applied to the salt (150 mM) treated tomato plants and then morphological traits, photosynthetic pigments, osmolytes, secondary metabolites, oxidative stress and antioxidant enzymes activity were assessed at 60 days after planting. The results revealed that salt stress decreased the growth parameters, photosynthetic pigments, soluble sugars and soluble protein whereas, content of proline, ascorbic acid, total phenols, malondialdehyde, hydrogen peroxide and the activity of antioxidant enzymes activity increased under salt stress. Moreover, Wuxal amino application through foliar or soil to salt stressed plants improved morphological traits, photosynthetic pigments, osmolytes, total phenol and antioxidant enzymes activity. Interestingly, the deleterious impact of salinity on tomato plants were significantly reduced and it can be evident from reduced MDA and H₂O₂ levels. These responses varied with the mode (foliar or soil) of application of Wuxal amino under different concentrations (2 cm L^-1 and 3 cm L^-1). It was concluded that application of Wuxal amino (2 cm L^-1, foliar) and (3 cm L^-1; soil) proved best and could be commercially used as eco-friendly tool for the protection of tomato plants grown under salinity stress.     

Effect of Shadowing on Survival of Bacteria under Conditions Simulating the Martian Atmosphere and UV Radiation

Spacecraft-associated spores and four non-spore-forming bacterial isolates were prepared in Atacama Desert soil suspensions and tested both in solution and in a desiccated state to elucidate the shadowing effect of soil particulates on bacterial survival under simulated Martian atmospheric and UV irradiation conditions. All non-spore-forming cells that were prepared in nutrient-depleted, 0.2-μm-filtered desert soil (DSE) microcosms and desiccated for 75 days on aluminum died, whereas cells prepared similarly in 60-μm-filtered desert soil (DS) microcosms survived such conditions. Among the bacterial cells tested, Microbacterium schleiferi and Arthrobacter sp. exhibited elevated resistance to 254-nm UV irradiation (low-pressure Hg lamp), and their survival indices were comparable to those of DS- and DSE-associated Bacillus pumilus spores. Desiccated DSE-associated spores survived exposure to full Martian UV irradiation (200 to 400 nm) for 5 min and were only slightly affected by Martian atmospheric conditions in the absence of UV irradiation. Although prolonged UV irradiation (5 min to 12 h) killed substantial portions of the spores in DSE microcosms (~5- to 6-log reduction with Martian UV irradiation), dramatic survival of spores was apparent in DS-spore microcosms. The survival of soil-associated wild-type spores under Martian conditions could have repercussions for forward contamination of extraterrestrial environments, especially Mars.     

Complete mitochondrial genomes of Chionomys roberti and Chionomys nivalis (Mammalia: Rodentia) from Turkey: Insight into their phylogenetic position within Arvicolinae

Organisms Diversity & Evolution - The complete mitochondrial DNA (mitogenome) sequences of Chionomys nivalis and C. roberti were first presented as reference mitogenomes by the current study...     

New insights into the substrate specificities of proton-coupled oligopeptide transporters from E. coli by a pH sensitive assay

Proton-coupled oligopeptide transporters (POTs) are secondary active transporters that facilitate di- and tripeptide uptake by coupling it to an inward directed proton electrochemical gradient. Here the substrate specificities of Escherichia coli POTs YdgR, YhiP and YjdL were investigated by means of a label free transport assay using the hydrophilic pH sensitive dye pyranine and POT overexpressing E. coli cells. The results confirm and extend the functional knowledge on E. coli POTs. In contrast to previous assumptions, alanine and trialanine appears to be substrates of YjdL, albeit poor compared to dipeptides. Similarly tetraalanine apparently is a substrate of both YdgR and YhiP.