An animal model to evaluate the function and regulation of the adaptively evolving stress protein SEP53 in oesophageal bile damage responses

Squamous epithelium in mammals has evolved an atypical stress response involving down-regulation of the classic HSP70 protein and induction of sets of proteins including one named SEP53. This atypical stress response might be due to the unusual environmental pressures placed on squamous tissue. In fact, SEP53 plays a role as an anti-apoptotic factor in response to DNA damage induced by deoxycholic acid stresses implicated in oesophageal reflux disease. SEP53 also has a genetic signature characteristic of an adaptively and rapidly evolving gene, and this observation has been used to imply a role for SEP53 in immunity. Physiological models of squamous tissue are required to further define the regulation and function of SEP53. We examined whether porcine squamous epithelium would be a good model to study SEP53, since this animal suffers from a bile-reflux disease in squamous oesophageal tissue. We have (1) cloned and sequenced the porcine SEP53 locus from porcine bacterial artificial chromosome genomic DNA, (2) confirmed the strikingly divergent nature of the C-terminal portion of the SEP53 gene amongst mammals, (3) discovered that a function of the conserved N-terminal domain of the gene is to maintain cytoplasmic localisation, and (4) examined SEP53 expression in normal and diseased porcine pars oesophagea. SEP53 expression in porcine tissue was relatively confined to gastric squamous epithelium, consistent with its expression in normal human squamous epithelium. Immunohistochemical staining for SEP53 protein in normal and damaged pars oesophagea demonstrated significant stabilisation of SEP53 protein in the injured tissue. These results suggest that porcine squamous epithelium would be a robust physiological model to examine the evolution and function of the SEP53 stress pathway in modulating stress-induced responses in squamous tissue

Intermediate-energy Coulomb excitation of Fe-52

The nucleus 52 Fe with s N = Z =26 d has been investigated using intermediate-energy Coulomb excitation in inverse kinematics. A reduced transition probability of B s E 2;0 1 + ! 2 1 + d = 817 s 102 d e 2 fm 4 to the first excited 2 + state at 849.0 ( 5 ) keV was deduced. The increase in excitation strength B s E 2 " d with respect to the even-mass neighbor 54 Fe ( B s E 2 " d = 620 s 50 d e 2 fm 4 ) agrees with shell-model expectations as the magic number N =28 is approached. This measurement completes the systematics of reduced transition strengths to the first excited 2 + state for the even-even N = Z nuclei up to mass A = 56status: publishe

E2 excitation strength in Ni-55: Coupling of the Ni-56 2(1)(+) collective core vibration to the f(7/2) odd neutron hole

The collectivity of the odd-mass nucleus 55 Ni was explored via intermediate-energy Coulomb excitation using a powerful combination of particle and g -ray spectroscopy. A g -ray at 2879 ( 18 ) keV was observed and is interpreted to deexcite a member of the core-coupled quintuplet 2 1 + s 56 Ni d ^ n f 7/2 −1 at the same energy. By similarity with the mirror nucleus 55 Co, transition probabilities were calculated assuming J p =9/2 − and J p =11/2 − for this state. Both assumptions lead to a transition strength higher than predicted by a large-scale shell-model calculation using the GXPF1 effective interaction and exceed the value predicted within a simple weak-coupling approachstatus: publishe