Nuclear receptor Rev-erb alpha (Nr1d1) functions in concert with Nr2e3 to regulate transcriptional networks in the retina.

The majority of diseases in the retina are caused by genetic mutations affecting the development and function of photoreceptor cells. The transcriptional networks directing these processes are regulated by genes such as nuclear hormone receptors. The nuclear hormone receptor gene Rev-erb alpha/Nr1d1 has been widely studied for its role in the circadian cycle and cell metabolism, however its role in the retina is unknown. In order to understand the role of Rev-erb alpha/Nr1d1 in the retina, we evaluated the effects of loss of Nr1d1 to the developing retina and its co-regulation with the photoreceptor-specific nuclear receptor gene Nr2e3 in the developing and mature retina. Knock-down of Nr1d1 expression in the developing retina results in pan-retinal spotting and reduced retinal function by electroretinogram. Our studies show that NR1D1 protein is co-expressed with NR2E3 in the outer neuroblastic layer of the developing mouse retina. In the adult retina, NR1D1 is expressed in the ganglion cell layer and is co-expressed with NR2E3 in the outer nuclear layer, within rods and cones. Several genes co-targeted by NR2E3 and NR1D1 were identified that include: Nr2c1, Recoverin, Rgr, Rarres2, Pde8a, and Nupr1. We examined the cyclic expression of Nr1d1 and Nr2e3 over a twenty-four hour period and observed that both nuclear receptors cycle in a similar manner. Taken together, these studies reveal a novel role for Nr1d1, in conjunction with its cofactor Nr2e3, in regulating transcriptional networks critical for photoreceptor development and function.

Cold fission: splitting the pombe cell at room temperature.

The mechanisms responsible for cytokinesis and its coordination with other events of the cell cycle are poorly understood. Genetic studies of cytokinesis in fission yeast are one useful approach to this problem. A number of conditional mutants of fission yeast that show defects in the formation of the septum of cytokinesis have been identified. Cloning of the genes affected in these mutants has begun to shed light upon the elements required to direct the construction of the division septum and also upon how the initiation of septum formation may be coordinated with mitosis.

Gene flow among wild and domesticated almond species: insights from chloroplast and nuclear markers

Hybridization has played a central role in the evolutionary history of domesticated plants. Notably, several breeding programs relying on gene introgression from the wild compartment have been performed in fruit tree species within the genus Prunus but few studies investigated spontaneous gene flow among wild and domesticated Prunus species. Consequently, a comprehensive understanding of genetic relationships and levels of gene flow between domesticated and wild Prunus species is needed. Combining nuclear and chloroplastic microsatellites, we investigated the gene flow and hybridization among two key almond tree species, the cultivated Prunus dulcis and one of the most widespread wild relative Prunus orientalis in the Fertile Crescent. We detected high genetic diversity levels in both species along with substantial and symmetric gene flow between the domesticated P. dulcis and the wild P. orientalis. These results were discussed in light of the cultivated species diversity, by outlining the frequent spontaneous genetic contributions of wild species to the domesticated compartment. In addition, crop-to-wild gene flow suggests that ad hoc transgene containment strategies would be required if genetically modified cultivars were introduced in the northwestern Mediterranean.

Organització nuclear dels gens que codifiquen per a les proteïnes làcties en cèlules epitelials mamàries en diferents estadis de desenvolupament

Estudi realitzat a partir d’una estada al Institut National de la Recherche Agronomique (INRA), a França, entre 2006 i 2008. En el ultims anys, estudis realitzats en diferents tipus cel•lulars han pogut determinar l’importància de l’organització nuclear en el control i regulació gènica. S’han realizat diferents experiments per tal de determinar si la posició dels gens de les proteïnes làcties en el nucli interfàsic de cel•lules epitelials mamaries és important per regular la seva expressió. Els gens de les proteïnes de la llet s’expressen a la glàndula mamaria durant la lactació en resposta a les hormones lactogèniques (majoritàriament prolactina i glucocorticoids). Mitjançant la tècnica de FISH (fluorescent in situ hibridization) en 3D s’ha caracteritzat la localització nuclear del gens WAP (whey acidic protein) i les caseïnes en cèl•lules epitelials mamaries de ratolí (HC11) cultivades en l’absència i presencia d’hormones lactogèniques. En absència d’hormones, els dos gens estan distribuïts dins del nucli de forma no aleatòria, el gen WAP es troba localitzat en l’interior del nucli, mentre que les caseïnes es troben localitzades prop de la perifèria nuclear. L’estimulació hormonal indueix un canvi significatiu en la distància dels dos gens a la perifèria nuclear. Així mateix, la posició del locus de la caseïna en relació al seu territori cromosòmic (CT) 5 està correlacionada amb la inducció hormonal i per tant amb la seva activació transcripcional, mentre que la posició del gen WAP amb relació al seu CT11 sembla més determinada pel context cromosòmic del gen. Per últim, no s’han trobat diferencies en la localització dels gens en relació a l'heterocromatina del centròmer, descrit com a compartiment repressiu, entre les cèl•lules estimulades amb hormones i les que no. En els dos casos s’ha trobat un gran percentatge de gens que no estan associats als centròmers.

Hand exposure in diagnostic nuclear medicine with 18F- and 99mTc-labelled radiopharmaceuticals - Results of the ORAMED project

Workers performing preparation and administration of radiopharmaceuticals in NM departments are likely to receive high local skin doses to the hands which may even surpass the dose limit of 500 mSv whenever radiation protection standards are insufficient. A large measurement campaign was organised within the framework of the ORAMED project to determine the dose distribution across the hands received during preparation and administration of 18F- and 99mTc-labelled radiopharmaceuticals. The final data, collected over almost 3 years, include 641 measurements from 96 workers in 30 NM departments from 6 European countries. Results have provided levels of reference doses for the considered standard NM diagnostic procedures (mean maximum normalised skin dose of 230 μSv/GBq, 430 μSv/GBq, 930 μSv/GBq and 1200 μSv/GBq for the administration of 99mTc, preparation of 99mTc, administration of 18F and preparation of 18F, respectively). Finger dose was analysed as a function of the potential parameters of influence showing that shielding is the most efficient means of radiation protection to reduce skin dose. An appropriate method for routine monitoring of the extremities is also proposed: the base of the index finger of the non-dominant hand is a suitable position to place the ring dosemeter, with its sensitive part oriented towards the palm side; its reading may be multiplied by a factor of 6 to estimate the maximum local skin dose. Finally, results were compared to earlier published data, which correspond mostly to individual works with a reduced number of workers and measurements.

Temper and Temperature: The Missing Link of Climate on Armed Conflicts

We investigate the causes of a conflict by adding ambient climate factors to the existing bundle of most significant variables. It turns out that – controlling for possible associations – temperature could actually induce a conflict. We emphasise that temperature could not be a dominant reason in starting a conflict; however, it could escalate the chances when other factors are present. This paper references some of the related psychological studies to support this claim. We also show that grievance factors could actually be rightfully effective in starting an internal conflict alongside greed based reasons. In the end, we believe that it could be informative to study ambient factors more often in economics.

Superfamily of steroid nuclear receptors: positive and negative regulators of gene expression.

The nuclear hormone receptor superfamily is characterized by an impressive functional diversity of its members despite a remarkable overall structural unity. A variety of ligands bind specifically to them and these receptors control gene networks that have profound effects on growth, development, and homeostasis. The ligand-receptor complexes recognize transcriptional enhancer DNA sequences, the hormone response elements, resulting in induction or repression of gene activity. The similarity between all these hormone response enhancer elements, as well as between the receptors themselves, indicates a conserved general strategy for the hormonal control of transcription by steroids. The activated receptors bind to responsive promoters and most likely mediate the assembly of stage- and tissue-specific transcription factor complexes that stimulate or inhibit gene expression.

Development of nuclear DNA probes for the typing of Trypanososma cruzi

We have developed and tested a new way of typing Trypanosoma cruzi, mamely the use of cloned nuclear DNA fragments as genetic markers. Restriction fragment length polymorphisms were verified on Soutern blots hybridized to random probes. Fragment patterns were analyzed and dendrograms constructed. Our results on well characterized laboratory strains correlate well to published isoenzyme studies. Some of the probes were also hybridized to chromosomes separated by pulse field gel electrophoresis a higher degree of heterogeneity was observed at this level.

Nuclear Factor I genomic binding associates with chromatin boundaries.

BACKGROUND: The Nuclear Factor I (NFI) family of DNA binding proteins (also called CCAAT box transcription factors or CTF) is involved in both DNA replication and gene expression regulation. Using chromatin immuno-precipitation and high throughput sequencing (ChIP-Seq), we performed a genome-wide mapping of NFI DNA binding sites in primary mouse embryonic fibroblasts. RESULTS: We found that in vivo and in vitro NFI DNA binding specificities are indistinguishable, as in vivo ChIP-Seq NFI binding sites matched predictions based on previously established position weight matrix models of its in vitro binding specificity. Combining ChIP-Seq with mRNA profiling data, we found that NFI preferentially associates with highly expressed genes that it up-regulates, while binding sites were under-represented at expressed but unregulated genes. Genomic binding also correlated with markers of transcribed genes such as histone modifications H3K4me3 and H3K36me3, even outside of annotated transcribed loci, implying NFI in the control of the deposition of these modifications. Positional correlation between + and - strand ChIP-Seq tags revealed that, in contrast to other transcription factors, NFI associates with a nucleosomal length of cleavage-resistant DNA, suggesting an interaction with positioned nucleosomes. In addition, NFI binding prominently occurred at boundaries displaying discontinuities in histone modifications specific of expressed and silent chromatin, such as loci submitted to parental allele-specific imprinted expression. CONCLUSIONS: Our data thus suggest that NFI nucleosomal interaction may contribute to the partitioning of distinct chromatin domains and to epigenetic gene expression regulation.NFI ChIP-Seq and input control DNA data were deposited at Gene Expression Omnibus (GEO) repository under accession number GSE15844. Gene expression microarray data for mouse embryonic fibroblasts are on GEO accession number GSE15871.

Influence of temperature on survival, growth and fecundity of the freshwater snail Indoplanorbis exustus (Deshayes)

To note the effect of temperature on survival, growth and fecundity, newly hatched (zero day old) snails Indoplanorbis exustus were cultured at 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees and 35 degreescentigrades constant temperatures and room temperature (17.5 degrees - 32.5 degrees centigrades). Individuals exposed to 10 degrees centigrades died within 3 days while those reared at 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees centigrades and room temperature survived for a period of 6, 27, 18, 16, 12 and 17 weeks respectively. An individual added on an average 0.21 mm and 0.45 mg, 0.35 mm and 7.94 mg, 0.63 mm and 15.5 mg, 0.81 mm and 27.18 mg, 1.07 mm and 41.48 mg and 0.78 mm and 31.2 mg to the shell diameter and body weight respectively at those temperatures per week. The snails cultured at 15 degrees centigrades died prior to attainment of sexual maturity. On an average, an individual produced 31.9 and 582.77, 54.86 and 902.18, 56.01 and 968.45, 49.32 and 798.68 and 62.34 and 1143.97 capsules and eggs respectively at 20 degrees, 25 degrees, 30 degrees, 35 degrees centigrades and room temperature (17.5 degrees - 32.5 degrees centigrades).

Biogeographic origin and radiation of the Old World crocidurine shrews (Mammalia: Soricidae) inferred from mitochondrial and nuclear genes.

The crocidurine shrews include the most speciose genus of mammals, Crocidura. The origin and evolution of their radiation is, however, poorly understood because of very scant fossil records and a rather conservative external morphology between species. Here, we use an alignment of 3560 base pairs of mitochondrial and nuclear DNA to generate a phylogenetic hypothesis for the evolution of Old World shrews of the subfamily Crocidurinae. These molecular data confirm the monophyly of the speciose African and Eurasian Crocidura, which also includes the fossorial, monotypic genus Diplomesodon. The phylogenetic reconstructions give further credit to a paraphyletic position of Suncus shrews, which are placed into at least two independent clades (one in Africa and sister to Sylvisorex and one in Eurasia), at the base of the Crocidura radiation. Therefore, we recommend restricting the genus Suncus to the Palaearctic and Oriental taxa, and to consider all the African Suncus as Sylvisorex. Using molecular dating and biogeographic reconstruction analyses, we suggest a Palaearctic-Oriental origin for Crocidura dating back to the Upper Miocene (6.8 million years ago) and several subsequent colonisations of the Afrotropical region by independent lineages of Crocidura.

Temperature effect upon blood consumption in Triatoma infestans

Different blood consumption speed was observed in Triatoma infestans - nymphs and adults - exposed to 12 degrees C and 28 degrees C. Exposure to optimal temperature (28 degrees C) allows the insects to consume blood at a rate of 9% per day. Significative relationship between blood amount present in the promesenteron and consumed blood was found at 28 degrees. Consumption of blood was drastically reduced at the lowest temperature. Accordingly, lack of ovaric development, oviposition and mating behaviour was observed in insects kept at 12 degrees C. Relationship between laboratory and field observations are discussed.