Genetic variation in the Y chromosome and sex-biased DNA methylation in somatic cells in the mouse

Mammalian Genome - Several lines of evidence suggest that the presence of the Y chromosome influences DNA methylation of autosomal loci. To better understand the impact of the Y chromosome on...     

Expression of Pituitary Adenylate Cyclase-Activating Peptide (PACAP) and PAC1 in the Periodontal Ligament After Tooth Luxation

Pituitary adenylate cyclase-activating peptide (PACAP) is widely distributed throughout the nervous system. PACAP not only acts as a neurotransmitter but also elicits a broad spectrum of biological action via the PACAP-specific receptor, PAC1. However, no studies have investigated PACAP and PAC1 in the periodontal ligament (PDL), so we aimed to perform this investigation in rats after tooth luxation. In the PDL of an intact first molar, there are few osteoclasts and osteoblasts. However, at days 3 and 5 after luxation, large PAC1-positive cells, thought to be osteoclasts because of their expression of the osteoclast marker, tartrate-resistant acid phosphatase, were detected in appreciable numbers. Osteoblast numbers increased dramatically on day 7 after luxation, and PAC1-positive mononuclear small cells were increased at day 14, many of which expressed the osteoblast marker, alkaline phosphatase. PACAP-positive nerve fibers were rarely detected in the PDL of intact first molars, but were increasingly evident at this site on days 5 and 7 after luxation. Double-immunofluorescence analysis demonstrated the relationship between PACAP-positive nerve fibers and PAC1-positive osteoclasts/-blasts in the PDL. At 5 days after luxation, PACAP-positive nerve fibers appeared in close proximity to PAC1-positive osteoclasts. At 7 days after luxation, PACAP-positive nerve fibers appeared in close proximity to PAC1-positive osteoblasts. These results suggest that PACAP may have effects on osteoclasts and osteoblasts in the PDL after tooth luxation and thus regulate bone remodeling after these types of injury.     

SIZE VARIATION,GROWTH STRATEGIES,AND THE EVOLUTION OF MODULARITY IN THE MAMMALIAN SKULL

Allometry is a major determinant of within‐population patterns of association among traits and, therefore, a major component of morphological integration studies. Even so, the influence of size variation over evolutionary change has been largely unappreciated. Here, we explore the interplay between allometric size variation, modularity, and life‐history strategies in the skull from representatives of 35 mammalian families. We start by removing size variation from within‐species data and analyzing its influence on integration magnitudes, modularity patterns, and responses to selection. We also carry out a simulation in which we artificially alter the influence of size variation in within‐taxa matrices. Finally, we explore the relationship between size variation and different growth strategies. We demonstrate that a large portion of the evolution of modularity in the mammalian skull is associated to the evolution of growth strategies. Lineages with highly altricial neonates have adult variation patterns dominated by size variation, leading to high correlations among traits regardless of any underlying modular process and impacting directly their potential to respond to selection. Greater influence of size variation is associated to larger intermodule correlations, less individualized modules, and less flexible responses to natural selection.     

Identification of GA3 in Neurospora crassa and Its Changes during Conidial Germination and Mycelial Growth

GA₃ was identified as a major GA in Neurospora crassa by gas chromatography/selected ion monitoring (GC/SIM) and its content was measured at various stages (0~96 hr after inoculation) of conidial germination and mycelial growth. The GA₃ content in the fungus was 190ng/g dry weight at the initial stage and then decreased rapidly; that per liter culture decreased soon after the inoculation, and then increased to 17.6 ng 96 hr after inoculation. The GA₃ concentration in the culture medium was around 10^?11 m throughout the 96-hr incubation. The physiological role of endogenous GA in Neurospora crassa is also discussed.     

Computer simulation of orthodontic tooth movement using CT image-based voxel finite element models with the level set method

Orthodontic tooth movement (OTM) is an adaptive biomechanical response of dentoalveolar components to orthodontic forces, in which remodeling of the alveolar bone occurs in response to changes in the surrounding mechanical environment. In this study, we developed a framework for OTM simulation by combining an image-based voxel finite element method, with a surface-tracking level set method using three-dimensional computer models. For a case study to demonstrate its capability of expressing clinical tooth movement, we observed displacement and rotation of the tooth under three types of force conditions. The simulation results demonstrate that the proposed simulation method has the potential to predict clinical OTM.     

Differential parameters between cytosolic 2‐Cys peroxiredoxins,PRDX1 and PRDX2

Peroxiredoxins are thiol‐dependent peroxidases that function in peroxide detoxification and H₂O₂ induced signaling. Among the six isoforms expressed in humans, PRDX1 and PRDX2 share 97% sequence similarity, 77% sequence identity including the active site, subcellular localization (cytosolic) but they hold different biological functions albeit associated with their peroxidase activity. Using recombinant human PRDX1 and PRDX2, the kinetics of oxidation and hyperoxidation with H₂O₂ and peroxynitrite were followed by intrinsic fluorescence. At pH 7.4, the peroxidatic cysteine of both isoforms reacts nearly tenfold faster with H₂O₂ than with peroxynitrite, and both reactions are orders of magnitude faster than with most protein thiols. For both isoforms, the sulfenic acids formed are in turn oxidized by H₂O₂ with rate constants of ca 2 × 10³ M^?1 s^?1 and by peroxynitrous acid significantly faster. As previously observed, a crucial difference between PRDX1 and PRDX2 is on the resolution step of the catalytic cycle, the rate of disulfide formation (11 s^?1 for PRDX1, 0.2 s^?1 for PRDX2, independent of the oxidant) which correlates with their different sensitivity to hyperoxidation. This kinetic pause opens different pathways on redox signaling for these isoforms. The longer lifetime of PRDX2 sulfenic acid allows it to react with other protein thiols to translate the signal via an intermediate mixed disulfide (involving its peroxidatic cysteine), whereas PRDX1 continues the cycle forming disulfide involving its resolving cysteine to function as a redox relay. In addition, the presence of C83 on PRDX1 imparts a difference on peroxidase activity upon peroxynitrite exposure that needs further study.     

Progress of National Multi-tissue Bank in Uruguay in the International Atomic Energy Agency (IAEA) Tissue Banking Programme

The transplant law of 1971 based on informed consent, allows people to register their willingness to be a donor upon death. Since 1978 the governmental Institution, the National Bank of Organs and Tissues (BNOT), have been regulated the organ and tissue donation. Important progress was implemented in the BNOT and specially in the National Multi-tissue Bank (NMTB). Since 2001 with the participation in the IAEA Tissue Banking Programme, Quality System Management has been implemented in the NMTB. New bio-production for radiosterilized tissues for the first time and improved procedures were carried out. As a result an increased production of high-quality tissues was obtained and distributed for clinical use.