Evolution Of Lactate Dehydrogenase Genes In Primates, With Special Consideration Of Nucleotide Organization In Mammalian Promoters

Concomitant with an increase in brain volume and mass, the allocation of energetic resources to the brain increased during stem anthropoid evolution, leading to humans. One mechanism by which this allocation may have occurred is through greater use of lactate as a neuronal fuel. Both the production of lactate, and conversion to pyruvate for use in aerobic metabolism, are catalyzed, in part, by the tetrameric enzyme lactate dehydrogenase (LDH). The two primary LDH genes, LDHA and LDHB, confer different rates of substrate turnover to the LDH enzyme, and these rates lend to the argument that LDHA supports anaerobic while LDHB supports aerobic metabolism. The expression profiles of these proteins shifted during primate evolution, with LDHA and LDHB the primary LDH proteins expressed in strepsirrhine and anthropoid brains, respectively. We demonstrate that this expression shift does not coincide with changes to protein structure. 202 Previous research has identified critical cis-regulatory elements within the LDHA promoter, demonstrating that transcriptional regulation is critical for proper expression of this gene. In this thesis, we characterize the promoters of LDHA and LDHB in primates, in order to determine the elements responsible for the expression shifts in brain during primate evolution. We identify motifs conserved across mammals, likely responsible for the common expression profiles. We also identify elements that were gained during different periods of primate evolution. Anthropoid-specific elements in the LDHA promoter include a modification of a known Sp1 site, as well as two putative repressor elements. Anthropoid-specific elements in the LDHB promoter include an oxidative phosphorylation element, which may coordinate aerobic metabolism pathways. In addition, both promoters have CpG sites conserved across mammals, which led us to hypothesize that species-specific and/or tissue-specific epigenetic modifications may have also changed during primate evolution. We conduct a cross-tissue, cross-species methylation analysis, and determine that CpG methylation patterns across tissues appear similar between human and dwarf lemur; however, methylation levels across species vary

(Z)-1-(3-Nitro­phen­yl)-2-(4-nitro­phen­yl)ethene

In the mol­ecule of the title compound, C14H10N2O4, the dihedral angle formed by the benzene rings is 53.66 (5)°. In the crystal structure, mol­ecules are linked into chains parallel to the [01] direction by inter­molecular C—H⋯O hydrogen-bonding inter­actions

Differential Prox-1 and CD 31 expression in mucousae, cutaneous and soft tissue vascular lesions and tumors

The study of lymphatic vessels and lymphatic tumors has been hampered with difficulty due to the overlapping morphological features between blood and lymphatic endothelial cells, as well as to the lack of specific lymphatic endothelial markers. Over the last few years, lymphatic vessels and lymphangiogenesis have received great attention owing to their putative implications in terms of metastatic dissemination and the promise of targets for lymphangiogenic therapy. Prox-1 is a nuclear transcription factor that plays a major role during embryonic lymphangiogenesis and is deemed to be a useful marker for differentiating lymphatic endothelial cells from the other blood vessels endothelial cells. Here, we describe a double-immunostaining strategy for formalin-fixed, paraffinembedded tissues that aims at evaluating the distribution of Prox-1 and CD 31 – a cytoplasmic pan-endothelial marker -in a series of 28 mucousae, cutaneous and soft tissue vascular lesions and tumors, including hemangiomas, lymphangiomas, lymphangiectasia, and Kaposi’s sarcomas. Our results showed that in non-lesional mucousae and skin, Prox-1 decorated exclusively the nuclei of endothelial cells in lymphatic vessels. Prox-1 stained almost all the benign lymphatic vascular lesions/tumors (91%) and was absent or only focally positive in 75% of blood vascular tumors. CD 31 stained endothelial cells of blood vessels of superficial and deep dermal plexuses, lymphatics, and all blood vascular lesions/tumors. Kaposi’s sarcomas were all positive for both CD 31 and Prox-1 markers. In conclusion, although Prox-1 expression in vascular lesions/tumors was not entirely restricted to tumors with known lymphatic differentiation, CD 31/Prox-1 double-immunolabeling can be used as an adjunct marker to identify lymphatic vessels in routinely processed formalin-fixed, paraffin-embedded samples

High School Media Too: A School Day in the Lives of Fifteen Teenagers

An observational study of media consumption and exposure throughout the school day of fifteen middle- and high-school students. The study measures exposure in ten second increments in all locations from home and car through school and others and details incidence and duration os media use. Results also details incidence of Concurrent Media Exposure (multi-tasking)

Water absorption in epoxy resins by electronic energy transfert

Presentación de Póster: Sesión C: Paper presentado en el Congreso "Polymers in the Third Millenium", 2-6 de septiembre de 2001 en Montpellier (Francia).Poster presentation: Session C: Paper presented at the Polymers in the Third Millennium Conference, 2–6 September, 2001, Montpellier, FranceWater absorption of an epoxy resin was studied by steady-state fluorescence spectroscopy and gravimetry. It was found that the intrinsic emission of the epoxy resin could be modified selecting an adequate excitation wavelength. The epoxy component of the resin was labelled with a trans-4-nitro-4′-aminostilbene fluorescent probe. Using an excitation wavelength of 340 nm it was possible to induce energy transfer to the suitable acceptor trans-4-nitro-4′-dialkylaminostilbene (NDAS). The relative fluorescence intensity /₄₃₃/ /₅₉₆ was used as a convenient means to follow the quenching effect of water on the emission of NDAS when excited via energy transfer. It was found that both the relative intensity and the water content increase linearly with the square root of diffusion time in the early stages of the process. The apparent Stern–Volmer constants for the quenching of the fluorophore, when excited directly in a fluid THF solution or in the polymer matrix, were very similar but lower than when the fluorophore was excited via energy transfer. It was concluded that, at least in the early stages of the water diffusion process, the interchromophoric distance should increase.Authors gratefully acknowledge project BE97-4472 (Brite EuRam) and to CAM (Pricit, Programa Grupos Estratégicos) for financial support

Silencing, Positive Selection and Parallel Evolution: Busy History of Primate Cytochromes c

Cytochrome c (cyt c) participates in two crucial cellular processes, energy production and apoptosis, and unsurprisingly is a highly conserved protein. However, previous studies have reported for the primate lineage (i) loss of the paralogous testis isoform, (ii) an acceleration and then a deceleration of the amino acid replacement rate of the cyt c somatic isoform, and (iii) atypical biochemical behavior of human cyt c. To gain insight into the cause of these major evolutionary events, we have retraced the history of cyt c loci among primates. For testis cyt c, all primate sequences examined carry the same nonsense mutation, which suggests that silencing occurred before the primates diversified. For somatic cyt c, maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses yielded the same tree topology. The evolutionary analyses show that a fast accumulation of non-synonymous mutations (suggesting positive selection) occurred specifically on the anthropoid lineage root and then continued in parallel on the early catarrhini and platyrrhini stems. Analysis of evolutionary changes using the 3D structure suggests they are focused on the respiratory chain rather than on apoptosis or other cyt c functions. In agreement with previous biochemical studies, our results suggest that silencing of the cyt c testis isoform could be linked with the decrease of primate reproduction rate. Finally, the evolution of cyt c in the two sister anthropoid groups leads us to propose that somatic cyt c evolution may be related both to COX evolution and to the convergent brain and body mass enlargement in these two anthropoid clades

Fighting Conflict: Violent Splits or Healthy Divides?

In this study, we develop a theory to understand how groups with strong divisions may, paradoxically, help members to cope with conflict and injustice. We test our theoretical predictions using a survey methodology and the data from 72 work groups across different industries. Consistent with our hypotheses, we found that group faultlines weakened the positive relationships between injustice and psychological health