Enhancement of in vitro growth of papaya multishoots by aeration

Efficient micropropagation of papaya (Carica papaya L.) has become crucial for multiplication of specific sex types of papaya or transgenic lines resistant to virus infection. In this study, aeration at different intervals with a 0.02 μm filter disc in the closure of culture flasks ensured exchange of gas components. The effect of aeration on development of multibuds to multishoots was investigated. Multibuds grown in culture flasks after one-week without aeration followed by a two-week aeration treatment caused a 41% increase in the number of shoots ≥0.5 cm, 42% increase in leaf expansion, and 17% increase in leaf numbers in comparison with unaerated materials. Ethylene and oxygen concentrations in the culture flasks were measured by gas chromatography and oxygen electrode at weekly intervals during the culture period. Oxygen concentrations were slightly different between aerated and unaerated culture flasks. Ethylene in the unaerated flask reached the highest level (0.11 ppm) 2 weeks after the treatment, while accumulation of ethylene in the aerated flasks was not detected. The multishoots grown for 3 weeks without aeration showed growth retardation on leaves and epinasty on petioles. This revised version was published online in June 2006 with corrections to the Cover Date.     

miR-126 regulates angiogenic signaling and vascular integrity

Precise regulation of the formation, maintenance, and remodeling of the vasculature is required for normal development, tissue response to injury, and tumor progression. How specific microRNAs intersect with and modulate angiogenic signaling cascades is unknown. Here, we identified microRNAs that were enriched in endothelial cells derived from mouse embryonic stem (ES) cells and in developing mouse embryos. We found that miR-126 regulated the response of endothelial cells to VEGF. Additionally, knockdown of miR-126 in zebrafish resulted in loss of vascular integrity and hemorrhage during embryonic development. miR-126 functioned in part by directly repressing negative regulators of the VEGF pathway, including the Sprouty-related protein SPRED1 and phosphoinositol-3 kinase regulatory subunit 2 (PIK3R2/p85-beta). Increased expression of Spred1 or inhibition of VEGF signaling in zebrafish resulted in defects similar to miR-126 knockdown. These findings illustrate that a single miRNA can regulate vascular integrity and angiogenesis, providing a new target for modulating vascular formation and function.     

The expression, function, and ontogeny of a novel T cell-activating protein, TAP, in the thymus

The TAP molecule is an allelic 12,000 m.w. membrane protein that participates in T cell activation. This report analyzes the expression, function, and ontogeny of this molecule in the thymus. TAP is expressed on a small subset (10 to 20%) of thymocytes which is distinct from its expression on a majority (70%) of peripheral T lymphocytes. In the adult thymus, the majority of the TAP-bearing thymocytes are cortisone-resistant, Thy-1+, TL-, J11D-, and PNA-, which localizes TAP expression to medullary thymocytes. Cortical thymocytes do not bear this determinant. Parallel functional studies demonstrated that TAP+ thymocytes are required for Con A and MLR responsiveness. Anti-TAP MAb plus PMA specifically induces proliferation of mature thymocytes comparable in magnitude to the Con A response. These results demonstrate that TAP expression defines the immunocompetent thymocyte compartment and, further, that this molecule is functional on these cells. The ontogeny of TAP expression was also analyzed. TAP is expressed early in fetal thymic development at a time when most T cell markers (except Thy-1 and the iL2-R) are absent. The small sub-population of adult L3T4- and Lyt-2- thymocytes, which resemble early fetal thymocytes, also express TAP. These early thymocytes are capable of being activated through the TAP molecule. The implications of these findings for T cell development and, in particular, the relationship of TAP to T cell receptor expression and acquisition of immunocompetence are discussed.     

A new aspect of view in synthesizing new type beta-adrenoceptor blockers with ancillary antioxidant activities.

A series of vanilloid-type beta-adrenoceptor blockers derived from antioxidant traditional Chinese herbal medicines were synthesized and tested for their antioxidant and adrenoceptor antagonistic activities. They all possessed significant beta-adrenoceptor blocking activities under in vitro experiments and radioligand binding assays. In addition, some compounds were further examined in in vivo tests and produced antagonist effects matching that of propranolol and labetalol by measurements of antagonism toward (-)isoproterenol-induced tachycardia and (-)phenylephrine-induced pressor responses in anesthetized rats. Furthermore, all of the compounds had antioxidant effects inherited from their original structures. In conclusion, compound 11 had the most potent beta-adrenoceptors blocking activity, 12 and 13 possessed high cardioselectivity, whereas 14, 15 and 16 possessed additional alpha-adrenoceptor blocking activity and 15 is the most effective antioxidant of all. The antioxidant activity may be due to their alpha and beta unsaturated side chain at position 1 and ortho-substituted methoxy moiety on 4-phenoxyethylamine.     

Studies of trachoma in families on Taiwan.

This study was undertaken to clarify the natural history and pathogenesis of trachoma. A group of families who live in a formerly trachoma hyperendemic area of Southern Taiwan were placed under continuous surveillance. The development in recent years of the micro immunofluorescence test for trachoma antibody, along with improved cell culture isolation methods, have allowed this surveillance to include repeated effective laboratory studies in addition to clinical observations. After four years' study of one group of families and three years of another, a number of interesting findings have been obtained. Evidence is presented supporting our hypothesis that trachoma is a disease of immumopathology and results from repeated reinfections with the trachoma organisms. The clinical findings of papillae, especially those of an acute nature, has been the clinical finding most closely associated with the isolation of the organism and the demonstration of antibody. Evidence is presented that transmission of the organism is usually within the family group. Although only trachoma immunotypes B and C previously had been associated with trachoma infection on Taiwan, data is presented from one family in which type D infections occurred. While a series of new and reinfections with trachoma organisms were demonstrated in some of the families under observation, the majority of the families not only showed no new infections but showed spontaneous healing or disappearance of clinical and laboratory evidence of trachoma infection. This tendency of active trachoma infection to disappear from a family in the absence of transmission of the organism parallels the rapid fall and prevalence of active trachoma on Taiwan during the past decade.     

Chloroplast DNA inheritance in theStellaria longipes complex (Caryophyllaceae)

Inheritance of chloroplast DNA (cpDNA) was examined in F₁ progenies derived from three crosses and three corresponding reciprocal crosses betweenStellaria porsildii andS. longifolia. Chloroplast DNA restriction fragments were analyzed using methods of nonradioactive digoxigenin-11-dUTP labeling and chemiluminescent detection with Lumi-Phos 530. Distinct interspecific restriction fragment polymorphisms were identified and used to demonstrate the mode of cpDNA inheritance. Mode of cpDNA inheritance differed among crosses. Two crosses in whichS. porsildii, SP2920-21, was the maternal parent exhibited three different types of plastids, maternal, paternal and biparental, among the F₁ hybrids, suggesting a biparental cpDNA inheritance and plastid sorting-out inStellaria.     

Cathepsin B Expression and the Correlation with Clinical Aspects of Oral Squamous Cell Carcinoma

Background

Cathepsin B (CTSB), a member of the cathepsin family, is a cysteine protease that is widely distributed in the lysosomes of cells in various tissues. It is overexpressed in several human cancers and may be related to tumorigenesis. The main purpose of this study was to analyze CTSB expression in oral squamous cell carcinoma (OSCC) and its correlation with patient prognosis.

Methodology/Principal Findings

Tissue microarrays were used to detect CTSB expression in 280 patients and to examine the association between CTSB expression and clinicopathological parameters. In addition, the metastatic effects of the CTSB knockdown on two oral cancer cell lines were investigated by transwell migration assay. Cytoplasmic CTSB expression was detected in 34.6% (97/280) of patients. CTSB expression was correlated with positive lymph node metastasis (p = 0.007) and higher tumor grade (p = 0.008) but not with tumor size and distant metastasis. In addition, multivariate analysis using a Cox proportional hazards model revealed a higher hazard ratio, demonstrating that CTSB expression was an independent unfavorable prognostic factor in buccal mucosa carcinoma patients. Furthermore, the Kaplan–Meier curve revealed that buccal mucosa OSCC patients with positive CTSB expression had significantly shorter overall survival. Moreover, treatment with the CTSB siRNA exerted an inhibitory effect on migration in OC2 and CAL27 oral cancer cells.

Conclusions

We conclude that CTSB expression may be useful for determining OSCC prognosis, particularly for patients with lymph node metastasis, and may function as a biomarker of the survival of OSCC patients in Taiwan.     

Purification, characterization, and kinetic mechanism of S-adenosyl-L-methionine:macrocin O-methyltransferase from Streptomyces fradiae

S-Adenosyl-L-methionine:macrocin O-methyltransferase catalyzes conversion of macrocin to tylosin, the terminal and main rate-limiting step of tylosin biosynthesis in Streptomyces fradiae. The O-methyltransferase was stabilized in vitro and purified to electrophoretic homogeneity. The purified enzyme had a molecular weight of 65,000 and consisted of two identical subunits of 32,000 with an isoelectric point of 4.5. The enzyme required Mg2+, Mn2+, or Co2+ for maximal activity and was catalytically optimal at pH 7.5-8.0 and 31 degrees C. The O-methyltransferase catalyzed the conversion of macrocin to tylosin at a stoichiometric ratio of 1:1. The enzyme also mediated conversion of lactenocin----desmycosin. The corresponding Vmax/Km ratios for the two analogous conversions were similar, and both enzymic conversions were susceptible to extensive competitive and noncompetitive inhibitions by macrolide metabolites. Steady-state kinetic studies for initial velocity, substrate analogue, and product inhibitions have allowed formulation of Ordered Bi Bi as the reaction mechanism for macrocin O-methyltransferase.     

Linkage of the HMP pathway to ATP generation by the proline cycle

The reactions catalyzed by proline oxidase and pyrroline-5-carboxylate reductase form a catalytic cycle linking the hexose-monophosphate pentose (HMP) pathway to mitochondrial ATP generation. The cycling of proline and pyrroline-5-carboxylate couples glucose oxidation to ATP generation by a mechanism independent of the Embden-Meyerhof pathway and the tricarboxylic acid cycle.