The nucleoporin Nup50 activates the Ran guanine nucleotide exchange factor RCC1 to promote NPC assembly at the end of mitosis

During mitotic exit, thousands of nuclear pore complexes (NPCs) assemble concomitant with the nuclear envelope to build a transport‐competent nucleus. Here, we show that Nup50 plays a crucial role in NPC assembly independent of its well‐established function in nuclear transport. RNAi‐mediated downregulation in cells or immunodepletion of Nup50 protein in Xenopus egg extracts interferes with NPC assembly. We define a conserved central region of 46 residues in Nup50 that is crucial for Nup153 and MEL28/ELYS binding, and for NPC interaction. Surprisingly, neither NPC interaction nor binding of Nup50 to importin α/β, the GTPase Ran, or chromatin is crucial for its function in the assembly process. Instead, an N‐terminal fragment of Nup50 can stimulate the Ran GTPase guanine nucleotide exchange factor RCC1 and NPC assembly, indicating that Nup50 acts via the Ran system in NPC reformation at the end of mitosis. In support of this conclusion, Nup50 mutants defective in RCC1 binding and stimulation cannot replace the wild‐type protein in in vitro NPC assembly assays, whereas excess RCC1 can compensate the loss of Nup50.     

2-Deoxy-D-Ribofuranosylation of Ethyl 5-Aminoimidazole-4-Carboxylate by Biotransformation and Chemical Methods

Abstract

In our studies aimed at the synthesis of inhibitors of enzymes involved in the de novo biosynthesis of purine nucleotides, the arabinosyl nucleoside (la), which is analogous to CAIR (lb), a central intermediate in the pathway, showed significant inhibition and substrate activities. We were therefore interested to synthesize the related 2-deoxy-D-ribosyl nucleotide (lc) for further enzymological studies.     

A Dual Model for Prioritizing Cancer Mutations in the Non-coding Genome Based on Germline and Somatic Events

We address here the issue of prioritizing non-coding mutations in the tumoral genome. To this aim, we created two independent computational models. The first (germline) model estimates purifying selection based on population SNP data. The second (somatic) model estimates tumor mutation density based on whole genome tumor sequencing. We show that each model reflects a different set of constraints acting either on the normal or tumor genome, and we identify the specific genome features that most contribute to these constraints. Importantly, we show that the somatic mutation model carries independent functional information that can be used to narrow down the non-coding regions that may be relevant to cancer progression. On this basis, we identify positions in non-coding RNAs and the non-coding parts of mRNAs that are both under purifying selection in the germline and protected from mutation in tumors, thus introducing a new strategy for future detection of cancer driver elements in the expressed non-coding genome.     

The effects of water temperature and hormone treatments on circulating LH and ovulation in tench (Tinca tinca)

The effectiveness of three hormone treatments commonly used for artificial reproduction of tench was evaluated under three thermal regimes, with focus on the need for dopamine antagonist. Mature females were divided into nine groups (n?=?8) and gradually exposed, over a 24?h period, to three temperature regimes: cold (18.1?±?0.02?°C), optimal (22.05?±?0.03?°C), and warm (26.3?±?0.01?°C). Each temperature regime comprised three experimental groups injected with one of three hormone treatments: carp pituitary extract (CPE; 3?mg?kg^?1); [D-Arg⁶, Pro⁹, NEt]-sGnRH (10???g?kg^?1); and [D-Arg⁶, Pro⁹, NEt]-sGnRH (10???g?kg^?1)?+?metoclopramide (20?mg?kg^?1) (combined treatment). No differences were found between ovulation induction (ovulation rate????75?%) with sGnRHa alone and with the combined treatment; whereas CPE at cold and warm water temperatures was significantly less effective (P?<?0.05) than above mentioned treatments. Administration of sGnRHa alone induced a gradual increase in luteinizing hormone (LH) levels with LH peaks close to ovulation, in contrast to the immediate LH surge with high LH levels throughout the entire study observed with the combined treatment under all thermal regimes. LH levels induced by GnRHa alone were significantly lower (P?<?0.05) at all temperatures compared to the combined treatment, with the exception of the final sample at 26?°C, when no difference was recorded. Based on these results we recommend the application of sGnRHa without the addition of dopamine antagonist as a reliable method for inducing ovulation in tench under suboptimal temperature conditions.     

Comparison of the contents of the main biochemical compounds and the antioxidant activity of some Spanish olive oils as determined by four different radical scavenging tests

The aim of this study was to compare the contents of the main biochemical compounds and the antioxidant capacity of five Spanish olive oils by four different antioxidant tests and to find out the most valuable oil for disease preventing diets. Fatty acids, sterols and individual antioxidant compounds in Arbequina, Hojiblanca, Extra Virgin, Picual and Lampante Spanish olive oils were determined. Antioxidant activities were done as well using different radical scavenging activities: total radical-trapping antioxidative potential by ABAP (TRAP-ABAP), radical scavenging activity by DPPH (RSA-DPPH), antioxidant assay by beta-carotene-linoleate model system (AA-beta-carotene) and total antioxidant status by ABTS (TAA-ABTS). The highest content of all studied antioxidant compounds (353; 329; 4.6 and 2.7 mg/kg for tocopherols, tocotrienols, polyphenols and o-diphenols, respectively) was found in Extra Virgin oil. Also the highest antioxidant capacity was observed in Extra Virgin oil (668 nM/ml; 29.4%; 40.4% and 2.64 mM TE/kg for TRAP-ABAP, RSA-DPPH, AA- beta-carotene and TAA-ABTS, respectively). The correlation between total phenols and antioxidant capacities measured by four methods was very high, but the highest for the beta-carotene (R = 0.9958). In conclusion, the best method for determination of the antioxidant capacity of olive oils is the beta-carotene test. Extra Virgin olive oil has high organoleptic properties and the highest antioxidant activity. The above-mentioned makes this oil a preferable choice for diseases preventing diets.     

Comparative content of some bioactive compounds in apples,peaches and pears and their influence on lipids and antioxidant capacity in rats

The aim of this study was to compare some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats. The content of total polyphenols (g/100g) was 0.23 +/- 0.03; 0.22 +/- 0.03 and 0.68 +/- 0.1 in peeled fruits and 0.48 +/- 0.04, 0.47 +/- 0.04 and 1.2 +/- 0.12 in peels of peaches, pears and apples, respectively. Caffeic, p-coumaric and ferulic acids and the total radical-trapping antioxidative potential (TRAP) values in peeled apples and their peels were significantly higher than in peaches and pears, respectively. Contrarary, no significant differences in the content of dietary fiber among the studied fruits were found. The content of all studied indices in peels was significantly higher than peeled fruits (p < 0.05 ). A good correlation between the total polyphenols and the TRAP values was found in all fruits. Diets supplemented with apples and to a less extent with peaches and pears have improved lipid metabolism and increased the plasma antioxidant potential especially in rats fed with added cholesterol. The highest content of biologically active compounds and the best results in the experiment on rats makes apple preferable for dietary prevention of atherosclerosis and other diseases.     

Frequency of aneuploidy related to age in porcine oocytes

It is generally accepted that mammalian oocytes are frequently suffering from chromosome segregation errors during meiosis I, which have severe consequences, including pregnancy loss, developmental disorders and mental retardation. In a search for physiologically more relevant model than rodent oocytes to study this phenomenon, we have employed comparative genomic hybridization (CGH), combined with whole genome amplification (WGA), to study the frequency of aneuploidy in porcine oocytes, including rare cells obtained from aged animals. Using this method, we were able to analyze segregation pattern of each individual chromosome during meiosis I. In contrast to the previous reports where conventional methods, such as chromosome spreads or FISH, were used to estimate frequency of aneuploidy, our results presented here show, that the frequency of this phenomenon was overestimated in porcine oocytes. Surprisingly, despite the results from human and mouse showing an increase in the frequency of aneuploidy with advanced maternal age, our results obtained by the most accurate method currently available for scoring the aneuploidy in oocytes indicated no increase in the frequency of aneuploidy even in oocytes from animals, whose age was close to the life expectancy of the breed.