Reversible inactivation of the transcriptional function of P53 protein by farnesylation

Background  

The use of integrating viral vectors in Gene therapy clinical trials has pointed out the problem of the deleterous effect of the integration of the ectopic gene to the cellular genome and the safety of this strategy. We proposed here a way to induce the death of gene modified cells upon request by acting on a pro-apoptotic protein cellular localization and on the activation of its apoptotic function.     

Ultrastructure of spermiogenesis and the spermatozoon in Castrada cristatispina Papi, 1951 (Platyhelminthes, Rhabdocoela, Typhloplanida)

Spermiogenesis in Castrada cristatispina begins with the formation of a zone of differentiation containing two centrioles with associated striated rootlets and an intercentriolar body between them. The centrioles give rise to two parallel, free flagella of the Trepaxonemata 9 + '1' pattern, growing out in opposite directions. Spermatids undergo a latero-ventral rotation of the flagella and a subsequent disto-proximal rotation of centrioles, and a distal cytoplasmic projection appears. The former rotation involves the compression of a row of microtubules and allows the recognition of a ventral side and a dorsal side. At the end of the differentiation, the centrioles and cortical microtubules lie parallel to the sperm axis. The modifications of the intercentriolar body and the migration of the nucleus and the centrioles toward the distal projection are described. The mature spermatozoon of C. cristatispina is filiform, tapered at both ends and shares several features with the other Rhabdocoela gametes. Nevertheless, the posterior extremity is capped by an electron-dense material. A gradient between mitochondria and dense bodies exists along the sperm axis. This study has enable us a phylogenetic approach of the Rhabdocoela through a comparison of the ultrastructural features of C. cristatispina with the other Rhabdocoela taxa. We propose the disto-proximal rotation of centrioles as a synapomorphy of the Rhabdocoela.     

Gene expression changes in spleens of the wildlife reservoir species, Eurasian wild boar （Sus scrofa）, naturally infected with Brucella suis biovar 2

Brucella suis is responsible for swine brucellosis worldwide.Of the five different 8.suis biovars (bv.), bv.2 appears restricted to Europe where it is frequently isolated from wild boar and hares, can infect pigs and can cause human brucellosis.In this study, the differ-ential gene expression profile was characterized in spleens of Eurasian wild boar naturally infected with B.suis by.2.Of the 20,201 genes analyzed in the microarray, 633 and 1,373 were significantly (fold change＞1.8; P＜0.01) upregulated and downregulated, respectively,in infected wild boar.The analysis was focused on genes that were over represented after conditional test for biological process gene on-tology.Upregulated genes suggested that B.suis bv.2 infection induced cell maturation, migration and/or proliferation in infected animals.The genes downregulated in infected wild boar impaired the activity of several important cellular metabolic pathways such as metabolism,cytoskeleton organization and biogenesis, immune response and lysosomal function and vesicle-mediated transport.In addition, the re-sponse to stress, sperm fertility, muscle development and apoptosis seemed to be also impaired in infected animals.These results sug-gested that B.suis by.2 may use strategies similar to other smooth brucellae to facilitate intraeellular multiplication and the developmentof chronic infections.To our knowledge, this is the first report of the analysis of gene expression profile in hosts infected with B.suis by.2, which is important to understand the molecular mechanisms at the host-pathogen interface in the main reservoir species with possible implications in the zoonotic cycle of the pathogen.     

Sequences homologous to Tc(s) transposable elements ofCaenorhabditis elegans are widely distributed in the phylum nematoda

Summary To have a better understanding of the evolutionary history of mobile elements within the nematodes, we examined the distribution and the conservation of homologues to transposable elements fromCaenorhabditis elegans (Tc1, Tc2, Tc3, Tc4, Tc5, and FB1) in 19 nematode species belonging to the class Secernentea. Our results show that Tc1 elements display a distribution restricted to the family Rhabditidae with poor conservation. The Tc2 and FB1 homologous elements have the same patchy distribution within the Rhabditidae. They were only found inCaenorhabditis and inTeratorhabditis. The Tc3 element is widely distributed among nematode species. Tc3 homologous elements are present in the majority of the Rhabditidae but also in two genera within the family Panagrolaimidae, and inBursaphelenchus, which belongs to the order Aphelenchida. Tc4 and Tc5 homologues show the most limited distribution of all tested elements, being strictly limited toC. elegans. These data indicate that in some cases, the distribution of transposable elements in the nematode cannot be explained by strict vertical transmission. The distribution of Tc3, Tc4, and Tc5 suggests that horizontal transmission may have occurred between reproductively isolated species during their evolutionary history.     

The different sources of variation in inbreeding depression, heterosis and outbreeding depression in a metapopulation of Physa acuta

Understanding how parental distance affects offspring fitness, i.e., the effects of inbreeding and outbreeding in natural populations, is a major goal in evolutionary biology. While inbreeding is often associated with fitness reduction (inbreeding depression), interpopulation outcrossing may have either positive (heterosis) or negative (outbreeding depression) effects. Within a metapopulation, all phenomena may occur with various intensities depending on the focal population (especially its effective size) and the trait studied. However, little is known about interpopulation variation at this scale. We here examine variation in inbreeding depression, heterosis, and outbreeding depression on life-history traits across a full-life cycle, within a metapopulation of the hermaphroditic snail Physa acuta. We show that all three phenomena can co-occur at this scale, although they are not always expressed on the same traits. A large variation in inbreeding depression, heterosis, and outbreeding depression is observed among local populations. We provide evidence that, as expected from theory, small and isolated populations enjoy higher heterosis upon outcrossing than do large, open populations. These results emphasize the need for an integrated theory accounting for the effects of both deleterious mutations and genetic incompatibilities within metapopulations and to take into account the variability of the focal population to understand the genetic consequences of inbreeding and outbreeding at this scale.     

Ecological change in the lower Omo Valley around 2.8 Ma

Late Pliocene climate changes have long been implicated in environmental changes and mammalian evolution in Africa, but high-resolution examinations of the fossil and climatic records have been hampered by poor sampling. By using fossils from the well-dated Shungura Formation (lower Omo Valley, northern Turkana Basin, southern Ethiopia), we investigate palaeodietary changes in one bovid and in one suid lineage from 3 to 2 Ma using stable isotope analysis of tooth enamel. Results show unexpectedly large increases in C₄ dietary intake around 2.8 Ma in both the bovid and suid, and possibly in a previously reported hippopotamid species. Enamel δ¹³C values after 2.8 Ma in the bovid (Tragelaphus nakuae) are higher than recorded for any living tragelaphin, and are not expected given its conservative dental morphology. A shift towards increased C₄ feeding at 2.8 Ma in the suid (Kolpochoerus limnetes) appears similarly decoupled from a well-documented record of dental evolution indicating gradual and progressive dietary change. The fact that two, perhaps three, disparate Pliocene herbivore lineages exhibit similar, and contemporaneous changes in dietary behaviour suggests a common environmental driver. Local and regional pollen, palaeosol and faunal records indicate increased aridity but no corresponding large and rapid expansion of grasslands in the Turkana Basin at 2.8 Ma. Our results provide new evidence supporting ecological change in the eastern African record around 2.8 Ma, but raise questions about the resolution at which different ecological proxies may be comparable, the correlation of vegetation and faunal change, and the interpretation of low δ¹³C values in the African Pliocene.     

Electrical frequency dependent characterization of DNA hybridization

The hybridization of oligomeric DNA was investigated using the frequency dependent techniques of electrochemical impedance spectroscopy (EIS) and quartz crystal microgravimetry (QCM). Synthetic 5'-amino terminated single stranded oligonucleotides (ssDNA) were attached to the exposed glass surface between the digits of microlithographically fabricated interdigitated microsensor electrodes using 3-glycidoxypropyl-trimethoxysilane. Similar ssDNA immobilization was achieved to the surface of the gold driving electrodes of AT-cut quartz QCM crystals using 3-mercaptopropyl-trimethoxysilane. Significant changes in electrochemical impedance values (both real and imaginary components) (11% increase in impedance modulus at 120 Hz) and resonant frequency values (0.004% decrease) were detected as a consequence of hybridization of the bound ssDNA upon exposure to its complement under hybridization conditions. Non-complementary (random) sequence sowed a modest decrease in impedance and a non-detectable change in resonant frequency. The possibility to detect the binding state of DNA in the vicinity of an electrode, without a direct connection between the measurement electrode and the DNA, has been demonstrated. The potential for development of label-free, low density DNA microarrays is demonstrated and is being pursued.     

Factor affecting body mass of young fat dormics (Glis glis) at weaning and by hibernation

This paper describes the factors affecting body mass at weaning and by hibernation of young fat dormice (Glis glis) We studied a free-living population in 1991 and 1992 in a mixed forest where 100 nest-boxes were placed. In the two years, 128 females used the nest-boxes to give birth and rear their litters and more than 900 dormice have been individually marked. Body mass of young at weaning was positively correlated to body mass of the mother in both years and to birth date in 1991, while litter size was negatively correlated to body mass of the young in 1992 only, when birth took place about two weeks later than in 1991. On the contrary, by the time of hibernation, young born later weighed significantly less than those born earlier in the season, and heavier young at weaning remained heavier by hibernation, while maternal body mass and litter size did not significantly affect body mass of young at this stage. Body mass of the mother was negatively related to the date of parturition and early breeding females lost weight during lactation, while females that bred later did not. It seems, therefore, that early breeding carries a cost that only females in good condition can afford. It appears that females may follow two strategies: those in poor body condition will delay pregnancy so that lactation occurs when environmental feeding conditions are at their best; those in good condition will breed earlier, since they can afford to lose weight during lactation. Their young will have more time to grow before hibernation and the mothers themselves will have a longer period of time for restoring their fat reserves.