Amino acid substitutions in CPC-LIKE MYB reveal residues important for protein stability in Arabidopsis roots.

TRYPTICHON (TRY) and ENHANCER OF TRY AND CPC2 (ETC2) encode R3-type MYB transcription factors that are involved in epidermal cell differentiation in Arabidopsis thaliana. TRY and ETC2 belong to the CPC-like MYB gene family, which includes seven homolog genes. Previously, we showed that among the CPC family members, TRY and ETC2 are characterized by rapid proteolysis compared with that of other members, and we demonstrated that this proteolysis is mediated by the proteasome-dependent pathway. In this study, we compared the functions of the wild-type TRY and ETC2 proteins and their amino acid-substituted versions. Our results showed that the substitution of amino acids in the C-terminal of TRY and ETC2 conferred them the ability to induce root hair formation. Furthermore, we confirmed that these mutations enhanced the stability of the TRY and ETC2 proteins. These results revealed that the amino acids, which are important for the functions of TRY and ETC2, mediate morphological pattern formation and can be useful in understanding the pathway determining the fate of root hair cells.

Characterization of phenyl pyrimidine derivatives that inhibit cytomegalovirus immediate-early gene expression.

Background Previously, we established a reporter cell line for human cytomegalovirus and screened anti-human cytomegalovirus compounds using the cell line. In this study, we characterized one of the identified compounds, 2,4-diamino-6-(4-methoxyphenyl)pyrimidine (coded as 35C10). Methods 50% Effective concentrations (EC50s) and 50% cytotoxic concentrations (CC50s) of 35C10 and its derivatives in human fibroblasts were determined by X-gal staining of the cells infected with human cytomegalovirus Towne strain expressing ß-galactosidase. Results EC50 and CC50 of 35C10 were 4.3 µM and >200 µM, respectively. Among several 35C10 derivatives, only one lacking 4-amino group of pyrimidine showed a similar EC50. 35C10 weakly inhibited murine cytomegalovirus, herpes simplex virus type 1, and varicella-zoster virus. A "time of addition" experiment suggested that 35C10 inhibited an early phase of the infection. Although 35C10 did not inhibit viral attachment to the cells nor the delivery of viral DNA to the nuclei, it decreased the number of infected cells expressing immediate-early 1 and 2 (IE1/IE2) proteins. 35C10 also inhibited the activation of a promoter for TRL4 in the reporter cells upon human cytomegalovirus infection, but not in the same reporter cells transfected with a plasmid expressing IE2. Conclusion Our findings suggest that 35C10 is a novel compound that inhibits IE gene expression in human cytomegalovirus-infected cells.

Expression and protein localization analyses of Arabidopsis GLABRA3 (GL3) in tomato (Solanum lycopersicum) root epidermis.

The arrangement of root hair and non-hair cells in the root epidermis provides a useful model for understanding the cell fate determination system in plants. A network of related transcription factors, including GLABRA3 (GL3), influences the patterning of cell types in Arabidopsis. GL3 is expressed primarily in root hair cells and encodes a bHLH transcription factor, which inhibits root hair differentiation in Arabidopsis root epidermis. By transforming the GL3 promoter::GFP into tomato, we demonstrated that the Arabidopsis GL3 promoter can function in tomato root epidermis. GFP fluorescence was observed in almost all root epidermal cells in the GL3::GFP transgenic tomato plants, indicating that all root epidermal cells of tomato possess root hair cell identity similar to that of Arabidopsis root hair cells. This is consistent with the phenotype of the tomato root, in which all epidermal cells produce root hairs. Moreover, we observed the localization of a GL3:GFP fusion protein in GL3::GL3:GFP transgenic tomato; although GL3 is known to exclusively localize in non-hair cell nuclei in Arabidopsis root epidermis, GL3:GFP fluorescence was detected not in the nuclei but in the cytoplasm of transgenic tomato epidermal cells. These results suggest that the nuclear localization mechanism differs between tomato and Arabidopsis.

Effect of phosphatidylcholine vesicle size on chirality induction and chiral discrimination.

The effect of the size of phosphatidylcholine (PC) vesicles on the induction of chirality and chiral discrimination was examined. Three kinds of vesicles formed with l-dimyristoyl, l-dipalmitoyl, or egg yolk PCs induced circular dichroisms (CDs) with the sign and intensity of the Cotton effect different from those of monomeric PCs. The CD intensity of the vesicles increased with a decrease in the vesicle size. Furthermore, the helicity of heterohelicene derivatives in a rapid equilibrium between right-handed (P) and left-handed (M) enantiomers was biased toward the M enantiomer side in l-PC vesicles, implying chiral discrimination by the vesicles. The extent of the bias toward the M enantiomer increased with an increase in vesicle size. Both the chirality induction and chiral discrimination were enhanced in a low-fluidity gel phase in comparison with those in a high-fluidity liquid-crystalline phase for every kind of vesicle of every size examined.

Difference in chiral recognition of gel and liquid-crystalline phases of phosphatidylcholine vesicles as determined by circular dichroism spectroscopy.

The circular dichroism (CD) spectra of three types of (L)phosphatidylcholine (PC) vesicles in aqueous solution showed differences in the sign and intensity of the Cotton effect compared with those of monomers in ethanol, indicating the existence of chiral environments in these vesicles. From the temperature dependence of CD intensities, the main phase transition temperatures between gel (Gel) and liquid-crystalline (LC) phases of the vesicles were estimated to be 40, 23, and 55 degrees C for dipalmitoyl PC, dimyristoyl PC and distearoyl PC, respectively. Furthermore, both low-fluidity Gel and high-fluidity LC phases recognized the chirality of incorporated 2-hydroxymethyl[5]thiaheterohelicene (5HM) with a helical structure, which undergoes a rapid racemization owing to a weak repulsion between the terminal hydrogen atoms. The ability for chiral recognition was evaluated using thermodynamic parameters for the equilibrium between P and M enantiomers of 5HM in the vesicles; the Gel phase manifested a higher recognition ability than the LC phase.

Study of chiral recognition of bilayered phosphatidylcholine vesicles using a helicene probe: characteristic function of cholesterol.

Incorporated into bilayered chiral phosphatidylcholine (PC) vesicles, 2-hydroxymethyl[5]thiaheterohelicene (5HM) having a labile helix that functioned as a chirality probe, exhibited induced CD absorptions. The Cotton effects of these absorptions demonstrated opposite signs according to the difference in chirality of PC applied, indicating the chiral recognition of the vesicles. The vesicles formed by PCs with unsaturation or acyl chains shorter than dipalmitoyl-PC (DPPC) exhibited a slightly stronger CD absorptions of 5HM, presumably because of an increase in the constraint by the vesicles. The phenomenon that an increase in fluidity results in a decrease in the CD intensity was examined by CD measurements at various temperatures. The vesicles formed with egg lecithin and bovine heart lecithin also induced CD absorptions of 5HM similar to those of (L)PC vesicles. The influence of cholesterol (Cho) and four kinds of analogs with different structures at the 3- or 5-position of a Cho molecule on the CD intensities was investigated. Following addition of Cho, the CD intensities of 5HM decreased slightly in the (L)DPPC vesicles and increased moderately in the (D)DPPC vesicles. On the other hand, by addition of Cho analogs the CD intensities of 5HM were nearly unchanged in (L)DPPC vesicles and weakened moderately in the (D)DPPC vesicles.

Airway troubles related to the double-lumen endobronchial tube in thoracic surgery.

PURPOSE: Several case reports indicate critical respiratory complications in relation to the double-lumen endobronchial tube (DLT). A prospective survey for the airway problems in using the DLT is presented. METHODS: One hundred adult patients undergoing thoracotomy for lung cancer were investigated. Tube malposition and airway obstruction were searched using a fiber-optic scope. The endobronchial cuff was positioned just below the trachcal carina while the trachea was intubated with a DLT (Rüsch). The distances of displacement, from the tracheal carina to the bronchial cuff, were measured during anesthesia using an epidural catheter, which had marks every 5 mm. The distances for correcting the tube position were measured at both the bronchial cuff and the level of the teethPaO2,PaCO2 andSPO2 were also measured. RESULTS: Malposition (displacement over 5 mm from the correct position) was found in 42 patients, and 40 of them were in a withdrawal direction, occurring at the postural change and during one-lung ventilation, especially during manipulation of the lung hilum. Correcting distances at the level of the teeth were 15.3-3-times longer than those at the bronchial cuff. Airway deformities and gradual withdrawal of the bronchial cuff were found in association with surgical manipulation. Obstruction occurred at the tips of the tracheal tube in four patients and the bronchial tube in six patients, and at the tip of both in two patients. Hypoxemia (PaO2<60 mmHg) occurred in four patients and hypercapnea (PaCO2>60 mm Hg) in two patients. CONCLUSION: Most of the DLT obstructions were associated with withdrawal malposition. Great attention to DLT displacement and airway deformity is advised.