Chromatin dynamics of the developmentally regulated P. lividus neural alpha tubulin gene

Over 40 years ago, Allfrey and colleagues (1964) suggested that two histone modifications, namely acetylation and methylation, might regulate RNA synthesis. Nowadays it is universally accepted that activation of gene expression strictly depends on enzymatic mechanisms able to dynamically modify chromatin structure. Here, using techniques including DNaseI hypersensitive site analysis, chomatin immunoprecipitation and quantitative PCR analysis, we have analyzed the dynamics of histone post-translation modifications involved in developmentally/spatially controlled activation of the sea urchin PlTalpha2 tubulin gene. We have demonstrated that only when the PlTalpha2 core promoter chromatin is acetylated on H3K9, tri-methylated on H3K4 and not di-methylated on H3K27, RNA pol II can be enrolled. In contrast, we have shown that when chromatin is methylated both on H3K9 (me2/3) and H3K27 (me2) and mono methylated on H3K4 the promoter is not accessible to RNA pol II. Our results suggest that, during P. lividus embryogenesis, both HAT/HDAC and HMT/HDM activities, which are able to regulate accessibility of the PlTalpha2 basal promoter to RNA polymerase II, are coordinately switched-on

Ancient Leishmaniasis in a Highland Desert of Northern Chile

Background Leishmaniasis is an infectious disease endemic today in many areas of South America. Methodology We discovered morphologic and molecular evidence of ancient infections in four female skulls in the archaeological cemetery of Coyo Oriente, in the desert of San Pedro de Atacama, northern Chile. The boney facial lesions visible in the skulls could have been caused by a number of chronic infections including chronic Leishmaniasis. This diagnosis was confirmed using PCR-sequenced analyses of bone fragments from the skulls of the affected individuals. Leishmaniasis is not normally found in the high-altitude desert of northern Chile; where the harsh climate does not allow the parasite to complete its life cycle. The presence of Leishmaniasis in ancient skulls from the region implies infection by the protozoan in an endemic area–likely, in our subjects, to have been the lowlands of northeastern Argentina or in southern Bolivia. Conclusions We propose that the presence of the disease in ancient times in the high altitude desert of San Pedro de Atacama is the result of an exogamic system of patrilocal marriages, where women from different cultures followed their husbands to their ancestral homes, allowing immigrant women, infected early in life, to be incorporated in the Atacama desert society before they became disfigured by the disease. The present globalization of goods and services and the extraordinary facile movement of people across borders and continents have lead to a resurgence of infectious diseases and re-emergence of infections such as Leishmaniasis. We show here that such factors were already present millennia ago, shaping demographic trends and the epidemiology of infections just as they do today

In silico characterization of the neural alpha tubulin gene promoter of the sea urchin embryo Paracentrotus lividus by phylogenetic footprinting

During Paracentrotus lividus sea urchin embryo development one alpha and one beta tubulin genes are expressed specifically in the neural cells and they are early end output of the gene regulatory network that specifies the neural commitment. In this paper we have used a comparative genomics approach to identify conserved regulatory elements in the P. lividus neural alpha tubulin gene. To this purpose, we have first isolated a genomic clone containing the entire gene plus 4.5 Kb of 50 upstream sequences. Then, we have shown by gene transfer experiments that its non-coding region drives the spatiotemporal gene expression corresponding substantially to that of the endogenous gene. In addition, we have identified by genome and EST sequence analysis the S. purpuratus alpha tubulin orthologous gene and we propose a revised annotation of some tubulin family members. Moreover, by computational techniques we delineate at least three putative regulatory regions located both in the upstream region and in the first intron containing putative binding sites for Forkhead and Nkx transcription factor families

Noises investigations and image denoising in femtosecond stimulated Raman scattering microscopy

In the literature of SRS microscopy, the hardware characterization usually remains separate from the image processing. In this article, we consider both these aspects and statistical properties analysis of image noise, which plays the vital role of joining links between them. Firstly, we perform hardware characterization by systematic measurements of noise sources, demonstrating that our in-house built microscope is shot noise limited. Secondly, we analyze the statistical properties of the overall image noise, and we prove that the noise distribution can be dependent on image direction, whose origin is the use of a lock-in time constant longer than pixel dwell time. Finally, we compare the performances of two widespread general algorithms, that is, singular value decomposition and discrete wavelet transform, with a method, that is, singular spectrum analysis (SSA), which has been adapted for stimulated Raman scattering images. In order to validate our algorithms, in our investigations lipids droplets have been used and we demonstrate that the adapted SSA method provides an improvement in image denoising

Ancient Leishmaniasis in a Highland Desert of Northern Chile

BACKGROUND:Leishmaniasis is an infectious disease endemic today in many areas of South America. METHODOLOGY:We discovered morphologic and molecular evidence of ancient infections in 4 female skulls in the archaeological cemetery of Coyo Oriente, in the desert of San Pedro de Atacama, Northern Chile. The boney facial lesions visible in the skulls could have been caused by a number of chronic infections including chronic Leishmaniasis. This diagnosis was confirmed using PCR-sequenced analyses of bone fragments from the skulls of the affected individuals.Leishmaniasis is not normally found in the high-altitude desert of Northern Chile; where the harsh climate does not allow the parasite to complete its life cycle. The presence of Leishmaniasis in ancient skulls from the region implies infection by the protozoan in an endemic area-likely, in our subjects, to have been the lowlands of North-Eastern Argentina or in Southern Bolivia. CONCLUSIONS:We propose that the presence of the disease in ancient times in the high altitude desert of San Pedro de Atacama is the result of an exogamic system of patrilocal marriages, where women from different cultures followed their husbands to their ancestral homes, allowing immigrant women, infected early in life, to be incorporated in the Atacama desert society before they became disfigured by the disease. The present globalization of goods and services and the extraordinary facile movement of people across borders and continents have lead to a resurgence of infectious diseases and re-emergence of infections such as Leishmaniasis. We show here that such factors were already present millennia ago, shaping demographic trends and the epidemiology of infections just as they do today

Ni(II) carcinogenesis and binding to Cap43 protein

Nickel compunds are well known as human carcinogens. The carcinogenity of nickel compounds has been confirmed by numerous epidemiological studies in humans and animals. The leading concepts in nickel carcinogenesis involves oxidative promutagenic DNA damage and epigenetic effects in chromatin resulting from nickel binding inside the cell nucleus. We have analyzed, for Ni(II) binding, the 30-amino acid C-terminal fragment of the protein, by a combined pH-metric and spectroscopic study. The fragment showed to bind one, two and three metal ions depending on the metal to ligand molar ratio

Neuronal and peripheral damages induced by synthetic psychoactive substances: an update of recent findings from human and animal studies

Preclinical and clinical studies indicate that synthetic psychoactive substances, in addition to having abuse potential, may elicit toxic effects of varying severity at the peripheral and central levels. Nowadays, toxicity induced by synthetic psychoactive substances poses a serious harm for health, since recreational use of these substances is on the rise among young and adult people. The present review summarizes recent findings on the peripheral and central toxicity elicited by "old" and "new" synthetic psychoactive substances in humans and experimental animals, focusing on amphetamine derivatives, hallucinogen and dissociative drugs and synthetic cannabinoids

Nickel interaction with metal binding sequences of histone H4

Nickel compounds are well known as human carcinogens. We investigated the issue of Ni(II) binding within the histone octamer. Using histone sequences in conjuction with the structural data we identified a binding site for Ni(II) ions located in the N-terminal tail of the histone H4

Leaf protein allocation across the canopy and during senescence in earlier and later senescing maize hybrids, and implications for the use of chlorophyll as a proxy of leaf N

Leaf chlorophyll (chl) and protein distribution were analyzed throughout grain filling in four modern maize hybrids with contrasting senescence behavior, at three different canopy levels and at low-N (LN, 18 kg N ha−1) and high-N (HN, 218 kg N ha−1) fertilization levels. Chl content assessed by SPAD resembled protein content only at LN, with delayed senescing genotypes having more leaf protein content than reference genotypes. Across N levels, relative chl content negatively related to light intensity (r2 = 0.59, P < 0.001), while relative protein content did only for the lowest part of the canopy (r2 = 0.54, P < 0.001), suggesting protein distribution in the canopy could be further improved. Relative Rubisco/LHCII partitioning increased from lower to upper leaves (P < 0.09) and differed among genotypes (P < 0.05) with no link to senescence behavior. Photosynthetic electron transport rates were lower at LN and differed between genotypes (P < 0.05) including those with similar leaf protein contents. Chl and protein contents were related across the entire dataset (r2 = 0.53, P < 0.001) but the slope (b) of this relationship varied widely depending on the leaf position (b = 0.026–0.019), the senescence stage (b = 0.014–0.020), the N level (b = 0.035–0.026) and the hybrid (b = 0.016–0.033). Our results suggest that in modern maize hybrids, leaf N utilization can be further improved and that genotypic together with other sources of variation should be included as specific variables in SPAD-based predictions of leaf N content.Instituto de Fisiología Vegeta