Domain Movement within a Gene: A Novel Evolutionary Mechanism for Protein Diversification

A protein function is carried out by a specific domain localized at a specific position. In the present study, we report that, within a gene, a specific amino acid sequence can move between a certain position and another position. This was discovered when the sequences of restriction-modification systems within the bacterial species Helicobacter pylori were compared. In the specificity subunit of Type I restriction-modification systems, DNA sequence recognition is mediated by target recognition domain 1 (TRD1) and TRD2. To our surprise, several sequences are shared by TRD1 and TRD2 of genes (alleles) at the same locus (chromosomal location); these domains appear to have moved between the two positions. The gene/protein organization can be represented as x-(TRD1)-y-x-(TRD2)-y, where x and y represent repeat sequences. Movement probably occurs by recombination at these flanking DNA repeats. In accordance with this hypothesis, recombination at these repeats also appears to decrease two TRDs into one TRD or increase these two TRDs to three TRDs (TRD1-TRD2-TRD2) and to allow TRD movement between genes even at different loci. Similar movement of domains between TRD1 and TRD2 was observed for the specificity subunit of a Type IIG restriction enzyme. Similar movement of domain between TRD1 and TRD2 was observed for Type I restriction-modification enzyme specificity genes in two more eubacterial species, Streptococcus pyogenes and Mycoplasma agalactiae. Lateral domain movements within a protein, which we have designated DOMO (domain movement), represent novel routes for the diversification of proteins

Phosphorus Particle Composite Plating with Ni-P Alloy Matrix

Ni-P alloy films containing phosphorus particles (called Ni-P alloy composite films) were fabricated by electrodeposition and were subsequently subjected to heat-treatment. Their compositions and microstructures were characterized, and their friction properties were evaluated using a ball-on-plate method. Composite electroplating in the nickel sulfate and chloride bath containing phosphorus acid and micrometer-sized phosphorus particles resulted in the Ni-P alloy coating with enhanced deposit phosphorus content. The phosphorus content of the films increased with increasing phosphorus particle concentration in the composite plating baths, reaching a maximum value of 29.0 atom %. The phosphorus particles were homogeneously distributed in this Ni- 29.0 atom % P alloy composite film. Heat-treatment converted the phases of the alloy composite films from an amorphous phase to stable crystalline phases, which are the same as those in the Ni- P binary alloy phase diagram. The friction coefficients of the Ni- P alloy films increased with increasing cycle number, whereas those of the Ni- P alloy composite films remained relatively constant. The alloy composite films had lower friction coefficients than the Ni- P alloy films both before and after heat-treatment. These results indicate that phosphorus particles are beneficial for maintaining a lower and stable friction coefficient during the ball-on-plate reciprocating friction test.ArticleJOURNAL OF THE ELECTROCHEMICAL SOCIETY 156: D283-D286(2009)journal articl

Finite-temperature phase diagram of two-component bosons in a cubic optical lattice: Three-dimensional t-J model of hard-core bosons

We study the three-dimensional bosonic t-J model, i.e., the t-J model of "bosonic electrons", at finite temperatures. This model describes the $s={1 \over 2}$ Heisenberg spin model with the anisotropic exchange coupling $J_{\bot}=-\alpha J_z$ and doped {\it bosonic} holes, which is an effective system of the Bose-Hubbard model with strong repulsions. The bosonic "electron" operator $B_{r\sigma}$ at the site $r$ with a two-component (pseudo-)spin $\sigma (=1,2)$ is treated as a hard-core boson operator, and represented by a composite of two slave particles; a "spinon" described by a Schwinger boson (CP$^1$ boson) $z_{r\sigma}$ and a "holon" described by a hard-core-boson field $\phi_r$ as $B_{r\sigma}=\phi^\dag_r z_{r\sigma}$. By means of Monte Carlo simulations, we study its finite-temperature phase structure including the $\alpha$ dependence, the possible phenomena like appearance of checkerboard long-range order, super-counterflow, superfluid, and phase separation, etc. The obtained results may be taken as predictions about experiments of two-component cold bosonic atoms in the cubic optical lattice.Comment: 8 pages, 14 figures, Size of figures has been adjuste

Effect of Long-Term Estrogen Replacement on Bladder Function in Old Female Rats

The effects of estradiol (E2) on urodynamic parameters were studied with twenty 16-month-old female Wistar rats. They were divided into 4 groups, i.e., Group I: untreated; Groups II and III: treated with E2 for 4 and 8 weeks, respectively; Group IV: treated with a placebo for 8 weeks. After treatment, we measured their plasma E2 levels, and recorded their voiding behavior for 24 h. Cystometry was performed and urodynamic parameters were analyzed. Particularly, bladder capacity as well as voided volume and frequency were surveyed. The results obtained were compared among groups. Levels of bladder capacity in the E2-replaced groups (Groups II, 0.52 ± 0.14 mL and Groups III, 0.58 ± 0.09 mL) were significantly (P < 0.05) higher than in the other groups (Group I, 0.38 ± 0.09 mL and Group IV, 0.40 ± 0.11 mL) respectively. The average voided volume was significantly (P < 0.05) higher in the E2-replaced groups (Groups II, 1.06 ± 0.22 mL and Groups III, 1.01 ± 0.16 mL) than in Group IV (0.79 ± 0.15 mL), respectively. Concerning the number of daily micturition per day, a significant difference (P < 0.05) was observed only between Group III (14.2 ± 2.7) and Group IV (18.8 ± 3.7). This suggests that E2-replacement therapy positively affects bladder function

Zero-Gravity Triaxial Shear Tests on Mechanical Properties of Liquefied Sand and Performance Assessment of Mitigations Against Large Ground Deformation

This paper concerns prediction of liquefaction-induced large deformation of geotechnical structures that will play major roles in practice of seismic performance design. To do this prediction, it is essential to establish a mechanical model for liquefied sand in which effective stress is null or extremely low. Although past model tests suggested that liquefied sand behaves similar to viscous liquid, there is an opinion against it that pore water pressure distribution in embedded structures produces an apparent rate-dependent behavior. This opinion was examined precisely and quantitatively by analyzing a full-scale model test to find that the pore pressure theory cannot account for the observed behavior. Then the authors conducted a new type of triaxial tests in which the effective stress was made extremely low, similar to the situation in fully liquefied sand, by free falling of a test device in a vertical shaft, thus making the gravity be zero, and a rate-dependent nature of liquefied sand was observed. By using the observed behavior of liquefied sand, a viscous model was developed. This viscous model was made use of to evaluate the performance of different mitigation measures that were proposed for river levees and other embankments subjected to liquefaction problems

Effect of Estrogen Replacement Therapy on Bladder Circulation in Old Female Rats

The effect of estradiol (E2) on the urinary bladder of old female rats was investigated by examining the histology and blood flow in the bladders. A total of 20 female Wistar rats aged 16 months were divided into 4 groups: Group I, 5 normal controls; Group II, 5 rats treated with E2 for 4 weeks; Group III, rats treated with E2 for 8 weeks; and Group IV, 5 rats receiving a placebo for 8 weeks. After the treatment, we removed the bladders, then weighed and stained them with hematoxylin and eosin. The muscle content was analyzed with the Elastica-van Gieson method, and the number of blood vessels with the Masson's trichrome method. Blood circulation in the bladders was also measured. The E2-replaced groups showed higher levels than the other groups in terms of blood flow in the bladder (20.6 ± 1.8 mL/min for Group II and 23.4 ± 1.5 mL/min for Group III, both P < 0.05 versus Groups I and IV), muscle content (2.33 ± 0.47 and 3.11 ± 0.48 for Groups II and III, respectively, both P < 0.05 versus Groups I and IV) and bladder weight (185.3 ± 6.2 mg and 193.2 ± 23.5 mg for Groups II and III; Group III showed P < 0.05 versus Groups I and IV). Differences in body weight and number of blood vessels among groups were not significant. We observed an increase in blood circulation, muscle content and weight of the bladder: E2-replacement therapy positively affected bladder functions