Solution structure determination of the two DNA-binding domains in the Schizosaccharomyces pombe Abp1 protein by a combination of dipolar coupling and diffusion anisotropy restraints

We have solved the solution structure of the N-terminal region of the fission yeast centromere protein, Abp1, bound to a 21-base pair DNA fragment bearing its recognition site (Mw = 30 kDa). Although the two DNA-binding domains in the Abp1 protein were defined well by a conventional NOE-based NMR methodology, the overall structure of the Abp1 protein was poorly defined, due to the lack of interdomain distance restraints. Therefore, we additionally used residual dipolar couplings measured in a weakly aligned state, and rotational diffusion anisotropies. Neither the NH residual dipolar couplings nor the backbone ¹⁵N T ₁/T ₂ data were sufficient to determine the overall structure of the Abp1 protein, due to spectral overlap. We used a combination of these two orientational restraints (residual dipolar coupling and rotational diffusion anisotropy), which significantly improved the convergence of the overall structures. The range of the observed T ₁/T ₂ ratios was wider (20–50 for the secondary structure regions of Abp1) than the previously reported data for several globular proteins, indicating that the overall shape of the Abp1DNA complex is ellipsoid. This extended form would facilitate the recognition of the two separate sites in the relatively long DNA sequence by the DNA-binding domains of Apb1.     

Genetic differentiation of piscivorous chub (genus Opsariichthys) in Japan,Korea and Russia

A comparison of allozyme variation, restriction fragment length polymorphisms in the mitochondrial DNA and partial sequences of the ND II gene (496 bp) was made among two lacustrine populations of the piscivorous chub (Opsariichthys uncirostris uncirostris) in Japan, four fluvial populations in Korea, one lacustrine population in Russia and one specimen from the Amur River (O. u. amurensis). All analyses indicate that the Japanese populations of piscivorous chub are separable from the Asian mainland populations of Korea and Russia. The latter populations were further divided into the Korean and Russian fish. Although opinions are divided on the phylogenetic position of the population in Lake Mikata, Japan, which shows unique morphological traits intermediate between those of the population in Lake Biwa and the mainland populations, the current analysis indicates a closer relationship to the population in Lake Biwa.     

Long-term follow-up of nasomaxillary epithelial inlay skin graft for the saddle nose

The nasomaxillary epithelial inlay skin graft described by H. D. Gillies in 1923 is one of the historical procedures of the twentieth century. Nowadays, this method has been thoroughly abandoned, and no long-term follow-up has been reported. In the Tokyo Metropolitan Police Hospital, between 1962 and 1983, 51 patients with saddle nose were treated using this procedure and a specially devised outer prosthesis. A follow-up study of these cases was attempted and that of nine cases was carried out. Six of nine patients have been using the outer prosthesis without any serious complications and are satisfied to varying extent. Three patients underwent further surgical treatment using autografts because of serious complications, which included full-thickness skin necrosis, refractory ulcer of the dorsum of nose, and anxiety about the unphysiological communication between the nasal and oral cavities.     

Rapid increase of vacuolar volume in response to salt stress

Suspension-cultured cells of mangrove [Bruguiera sexangula (Lour.) Poir.] showed a rapid increase in vacuolar volume under salt stress, although there was no change in the cell volume. The rapid increase in the vacuolar volume was an active process, which followed the activation of the tonoplast H(+)-ATPase and the vacuolar acid phosphatase. The same phenomenon was observed in barley (Hordeum vulgare L. cv. Doriru) root meristematic cells under salt stress but not in pea ( Pisum sativum L.). Increases in vacuolar volume could potentially protect the cytoplasm by decreasing the cytoplasmic volume during the initial phases of salt stress.     

Expression of angiotensin type 1 and 2 receptors in brain after transient middle cerebral artery occlusion in rats

Angiotensin II (Ang II) type 2 receptors (AT2Rs) have been associated with apoptosis. We hypothesized that AT2Rs are increased in stroke and may contribute effects of stroke to the brain. To test this, we have examined the expression of Ang II type 1 receptor (AT1R), AT2R and Ang II levels in the brain 24 h after transient middle cerebral artery occlusion (MCAO). The densities of AT1R and AT2R were measured by quantitative autoradiography (n=6). The levels of Ang II were measured by radioimmunoassay (RIA) (n=6) and by immunohistochemistry (n=3). AT1R levels on autoradiography showed a significant decrease (0.87±0.06 to 1.39±0.07 fmol/mg, p<0.01) in the ventral cortex of the stroke side compared to the cortices of non-stroke (NS) rats (n=4). There was no significant difference on ATIR in the contralateral verbal cortex of the stroke rats compared to NS control. In contrast, levels of AT2R in the ventral cortex of both the stroke and the contralateral sides were significantly increased (0.77±0.06, p<0.05 and 0.91±0.05, p<0.01 compared to 0.60±0.03 fmol/mg tissue, respectively). RIA showed that Ang II in the ventral cortex of both the stroke and the contralateral sides were significantly increased (241.63±47.72, p<0.01 and 165.51±42.59, p<0.05 compared to 76.80±4.10 pg/g tissue, respectively). Also, Ang II in the hypothalamus was significantly increased (179.50±17.49 to 118.50±6.65 pg/g tissue, p<0.05). Immunohistochemistry confirmed the increase of Ang II. These results demonstrate that brain Ang II and AT2Rs are increased whereas AT1Rs are decreased after transient MCAO in rats. We conclude that in stroke, Ang II and AT2R are activated and may contribute neural effects to brain ischemia.     

Autoantibodies against cardiac troponin I are responsible for dilated cardiomyopathy in PD-1-deficient mice

We recently reported that mice deficient in the programmed cell death-1 (PD-1) immunoinhibitory coreceptor develop autoimmune dilated cardiomyopathy (DCM), with production of high-titer autoantibodies against a heart-specific, 30-kDa protein. In this study, we purified the 30-kDa protein from heart extract and identified it as cardiac troponin I (cTnI), encoded by a gene in which mutations can cause familial hypertrophic cardiomyopathy (HCM). Administration of monoclonal antibodies to cTnI induced dilatation and dysfunction of hearts in wild-type mice. Monoclonal antibodies to cTnI stained the surface of cardiomyocytes and augmented the voltage-dependent L-type Ca2+ current of normal cardiomyocytes. These findings suggest that antibodies to cTnI induce heart dysfunction and dilatation by chronic stimulation of Ca2+ influx in cardiomyocytes.