Rapid communication: Linkage and physical mapping of the porcine melanocortin-4 receptor (MC4R) gene

Genus and Species. Sus scrofa. Locus. Pig Melanocortin-4 Receptor (MC4R) gene. Source and Description of Primers. Primers were designed from well-conserved sequence regions between the human and rat MC4R genes (Genbank accession no. S77415 and U67863, respectively). The primers were used to amplify approximately 760 bp of the porcine MC4R gene from genomic DNA. The sequence of the PCR product showed 92.2 and 97.6% identities at the nucleotide and amino acid levels, respectively, to the corresponding human sequence. The porcine MC4R sequence has been submitted to GenBank (accession no. AF087937). Using this sequence, pig-specific primers were designed

Rapid Communication: Genetic Linkage Mapping of the Porcine Fibroblast Growth Factor 7 (FGF7) Gene

Source and Description of Primers. The forward primer was developed from a human fibroblast growth factor ( FGF7) cDNA sequence (GenBank accession no. L06243), and the reverse primer was a published primer (Kelley et al., 1992). These primers were used to amplify a 1.3-kb fragment from porcine genomic DNA. This fragment included regions corresponding to exon 2, exon 3, and the intron flanked by these two exons. Sequences were obtained from both ends of the PCR fragment and compared with a human sequence showing 95.9% identity at the amino acid level in a 73-amino acid overlap. Sequences produced in this experiment have been submitted to GenBank (accession no. AF052657)

Thermonuclear burst physics with RXTE

Recently we have made measurements of thermonuclear burst energetics and recurrence times which are unprecedented in their precision, largely thanks to the sensitivity of the Rossi X-ray Timing Explorer. In the "Clocked Burster", GS 1826-24, hydrogen burns during the burst via the rapid-proton (rp) process, which has received particular attention in recent years through theoretical and modelling studies. The burst energies and the measured variation of alpha (the ratio of persistent to burst flux) with accretion rate strongly suggests solar metallicity in the neutron star atmosphere, although this is not consistent with the corresponding variation of the recurrence time. Possible explanations include extra heating between the bursts, or a change in the fraction of the neutron star over which accretion takes place. I also present results from 4U 1746-37, which exhibits regular burst trains which are interrupted by "out of phase" bursts.Comment: 4 pages, 2 figures, AIP conference proceedings format. To appear in the proceedings of the "X-ray Timing 2003: Rossi and Beyond" meeting held in Cambridge, MA, November, 200

Two ~35 day clocks in Her X-1: evidence for neutron star free precession

We present evidence for the existence of two ~35 day clocks in the Her X-1/HZ Her binary system. ~35 day modulations are observed 1) in the Turn-On cycles with two on- and two off-states, and 2) in the changing shape of the pulse profiles which re-appears regularly. The two ways of counting the 35 day cycles are generally in synchronization. This synchronization did apparently break down temporarily during the long Anomalous Low (AL3) which Her X-1 experienced in 1999/2000, in the sense that there must have been one extra Turn-On cycle. Our working hypothesis is that there are two clocks in the system, both with a period of about ~35 days: precession of the accretion disk (the less stable "Turn-On clock") and free precession of the neutron star (the more stable "Pulse profile clock"). We suggest that free precession of the neutron star is the master clock, and that the precession of the accretion disk is basically synchronized to that of the neutron star through a feed-back mechanism in the binary system. However, the Turn-On clock can slip against its master when the accretion disk has a very low inclination, as is observed to be the case during AL3. We take the apparent correlation between the histories of the Turn-Ons, of the Anomalous Lows and of the pulse period evolution, with a 5 yr quasi-periodicity, as evidence for strong physical interaction and feed-back between the major components in the system. We speculate that the 5 yr (10 yr) period is either due to a corresponding activity cycle of HZ Her or a natural ringing period of the physical system of coupled components. The question whether free precession really exists in neutron stars is of great importance for the understanding of matter with supra-nuclear density.Comment: 6 pages, 5 figures, accepted for publication by A&

Swift/BAT measurements of the cyclotron line energy decay in the accreting neutron star Her X-1: indication of an evolution of the magnetic field?

Context: The magnetic field is a crucial ingredient of neutron stars. It governs the physics of accretion and of the resulting high-energy emission in accreting pulsars. Studies of the cyclotron resonant scattering features (CRSFs) seen as absorption lines in the X-ray spectra of the pulsars permit direct measuremets of the field strength. Aims: From an analysis of a number of pointed observations with different instruments, the energy of CRSF, Ecyc, has recently been found to decay in Her X-1, which is one of the best-studied accreting pulsars. We present our analysis of a homogeneous and almost uninterrupted monitoring of the line energy with Swift/BAT. Methods: We analyzed the archival Swift/BAT observations of Her X-1 from 2005 to 2014. The data were used to measure the CRSF energy averaged over several months. Results: The analysis confirms the long-term decay of the line energy. The downward trend is highly significant and consistent with the trend measured with the pointed observations: dEcyc/dt ~-0.3 keV per year. Conclusions: The decay of Ecyc either indicates a local evolution of the magnetic field structure in the polar regions of the neutron star or a geometrical displacement of the line-forming region due to long-term changes in the structure of the X-ray emitting region. The shortness of the observed timescale of the decay, -Ecyc/(dEcyc/dt) ~ 100 yr, suggests that trend reversals and/or jumps of the line energy might be observed in the future.Comment: Accepted for publication in Astronomy&Astrophysic

Mapping of Two High Mobility Group Protein Genes for Growth and Composition traits in Pig

Using information from the human genome two new candidate genes for growth and composition traits were studied. The porcine high mobility group isoforms protein [HMGI(Y) and HMGIC] genes were chosen based on their presumed role in fat cell growth and differentiation. The HMGI(Y) gene was assigned to pig chromosome 7 by both linkage and physical mapping methods. This assignment agrees with other comparative mapping studies as the human HMGI(Y) gene maps to human chromosome 6p21, which is known to share a homology with pig chromosome 7. Interestingly, the pig HMGIC gene was assigned to the pig chromosome 1 by both methods. The localization of these candidate genes in the pig genome could improve the power of analyses for quantitative traits associated with growth and meat quality traits

Examining Genetic Differences in Farm Raised Pacific White Shrimp

Genomic DNA was extracted from ten shrimp of the Pacific white shrimp or Litopenaeus vannamei species and used to find single nucleotide polymorphisms (SNPs) in the Alpha-amylase (_-AMY) and the Cathepsin-L (CTSL) genes. This study lays the groundwork for future research to examine the association of genetic markers and the growth rate of farm raised pacific white shrimp