The boundary-expressed EPIDERMAL PATTERNING FACTOR-LIKE2 gene encoding a signaling peptide promotes cotyledon growth during Arabidopsis thaliana embryogenesis

The shoot organ boundaries have important roles in plant growth and morphogenesis. It has been reported that a gene encoding a cysteine-rich secreted peptide of the EPIDERMAL PATTERNING FACTOR-LIKE (EPFL) family, EPFL2, is expressed in the boundary domain between the two cotyledon primordia of Arabidopsis thaliana embryo. However, its developmental functions remain unknown. This study aimed to analyze the role of EPFL2 during embryogenesis. We found that cotyledon growth was reduced in its loss-of-function mutants, and this phenotype was associated with the reduction of auxin response peaks at the tips of the primordia. The reduced cotyledon size of the mutant embryo recovered in germinating seedlings, indicating the presence of a factor that acted redundantly with EPFL2 to promote cotyledon growth in late embryogenesis. Our analysis suggests that the boundary domain between the cotyledon primordia acts as a signaling center that organizes auxin response peaks and promotes cotyledon growth.     

PARK2-mediated mitophagy is involved in regulation of HBEC senescence in COPD pathogenesis

Cigarette smoke (CS)-induced mitochondrial damage with increased reactive oxygen species (ROS) production has been implicated in COPD pathogenesis by accelerating senescence. Mitophagy may play a pivotal role for removal of CS-induced damaged mitochondria, and the PINK1 (PTEN-induced putative kinase 1)-PARK2 pathway has been proposed as a crucial mechanism for mitophagic degradation. Therefore, we sought to investigate to determine if PINK1-PARK2-mediated mitophagy is involved in the regulation of CS extract (CSE)-induced cell senescence and in COPD pathogenesis. Mitochondrial damage, ROS production, and cell senescence were evaluated in primary human bronchial epithelial cells (HBEC). Mitophagy was assessed in BEAS-2B cells stably expressing EGFP-LC3B, using confocal microscopy to measure colocalization between TOMM20-stained mitochondria and EGFP-LC3B dots as a representation of autophagosome formation. To elucidate the involvement of PINK1 and PARK2 in mitophagy, knockdown and overexpression experiments were performed. PINK1 and PARK2 protein levels in lungs from patients were evaluated by means of lung homogenate and immunohistochemistry. We demonstrated that CSE-induced mitochondrial damage was accompanied by increased ROS production and HBEC senescence. CSE-induced mitophagy was inhibited by PINK1 and PARK2 knockdown, resulting in enhanced mitochondrial ROS production and cellular senescence in HBEC. Evaluation of protein levels demonstrated decreased PARK2 in COPD lungs compared with non-COPD lungs. These results suggest that PINK1-PARK2 pathway-mediated mitophagy plays a key regulatory role in CSE-induced mitochondrial ROS production and cellular senescence in HBEC. Reduced PARK2 expression levels in COPD lung suggest that insufficient mitophagy is a part of the pathogenic sequence of COPD.     

A New Enzyme,Agmatine Oxidase,from Fungi

A new enzyme, agmatine oxidase, was found in Penicillium chrysogenum. The oxidation products of agmatine with the enzyme were identified as γ-guanidinobutyraldehyde, NH₃ and H₂O₂. The enzyme rapidly oxidized agmatine, and slightly oxidized histamine, putrescine, 1,3-diaminopropane and cadaverine. Monoamines, polyamines and guanidyl derivatives were not oxidized by the enzyme. Maximal formation of the enzyme of P. chrysogenum was observed in the early stationary phase of growth, and thereafter the enzyme disappeared with consumption of substrate. In addition to agmatine, spermine, spermidine and putrescine were also effective as nitrogen sources. Agmatine oxidase was found in mycelia of fungi belonging to the genera of Aspergillus, Penicillium, Absidia, Fusarium, Mucor, Gibberella, Cylindrocarpon and Monascus when they were grown in agmatine-containing medium.     

Cell Cycle Withdrawal Promotes Myogenic Induction of Akt, a Positive Modulator of Myocyte Survival

During myogenesis, proliferating myoblasts withdraw from the cell cycle, acquire an apoptosis-resistant phenotype, and differentiate into myotubes. Previous studies indicate that myogenic induction of the cyclin-dependent kinase inhibitor p21 results in an inhibition of apoptotic cell death in addition to its role as a negative cell cycle regulator. Here we demonstrate that the protein encoded by the Akt proto-oncogene is induced in C2C12 cells during myogenic differentiation with a corresponding increase in kinase activity. In differentiating cultures, expression of dominant-negative forms of Akt increase the frequency of cell death whereas expression of wild-type Akt protects against death, indicating that Akt is a positive modulator of myocyte survival. Antisense oligonucleotides against p21 block cell cycle withdrawal, inhibit Akt induction, and enhance cell death in differentiating myocyte cultures. Adenovirus-mediated transfer of wild-type or constitutively active Akt constructs confer partial resistance to cell death under conditions where cell cycle exit is blocked by the antisense oligonucleotides. Collectively, these data indicate that cell cycle withdrawal facilitates the induction of Akt during myogenesis, promoting myocyte survival.     

Reaction System of Haemophilus,Superhelical DNA-relaxing Enzyme is Useful for Screening of DNA-binding Substance

Several substances with antioxidant activity were isolated from the mixture of dehydroascorbic acid and tryptophan when reacted together in ethanol. One of the main antioxidant products was obtained in crystalline form from an n-butanol extract of the reaction mixture by means of Sephadex column chromatography followed by HPLC with a reversed phase column. ¹H- and ¹³C-NMR of the product and its acetate showed its structure as a condensate of dehydroascorbic acid and tryptophan with each single molecule involving a C-spiro structure. By a POV test the activity of this substance was about two-thirds of that of BHA on a molar basis, and the activity of the reaction mixture is greatly attributable to this substance.     

Symplectoteuthis bioluminescence (1) Structure and binding form of chromophore in photoprotein of a luminous squid

Thechromophore in the luminous squid, Symplectoteuthis oualaniensis, was identified to be dehydrocoelenterazine. This chromophore exists as conjugate adduct in the photoprotein.     

Heterogeneity of HLA-G Genes Identified by Polymerase Chain Reaction/Single Strand Conformational Polymorphism (PCR/SSCP)

A genomic HLA-G clone named 7.0E was isolated from a Japanese placenta. The deduced amino acid sequence of the 7.0E was identical to two HLA-G genomic clones and two cDNA clones previously described. The DNA sequences of α1 and α2 domains of the HLA-G gene from 5 cell lines also encoded the same amino acids. However, a 14 bp insertion, ATTTGTTCATGCCT, was present in the 3′ untranslated region of 7.0E compared with the originally described HLA-G clone (HLA 6.0). Polymerase chain reaction (PCR)/single strand conformational polymorphism (SSCP) analysis of exon 8 allowed the HLA-G gene to be classified into two alternative types, G6.0 and 7.0 E, those correlated to the absence or the presence of the 14 bp stretch. Each group had minor sequence variant(s), and the alleles of the 7.0E-type were more heterogeneous than those of the G6.0- type. The 14 bp deletion is present only in the G6.0-type of HLA-G alleles among HLA class I genes. Thus it was suggested that G6.0 alleles were generated after diversification of the HLA-G.     

The expression and biological activity of IL-2 receptor on a human pancreas cancer cell line

To ascertain whether the tumor cells can regulate the host immune systems through the production of the cytokines or their receptors, we examined the expressions of tumor necrosis factor (TNF), tumor necrosis factor (TNF), interleukin 2 (IL-2) and interleukin 2 receptor alpha chain (IL-2R) on the human cancer cell lines by Northern blot analysis. We used K562 (leukemia cell line), MCF-7 (breast cancer cell line), LS180, HT29 (colon cancer cell lines), SH101 (gastric cancer cell line) and PH101 (pancreas cancer cell line). Expressions of TNF, TNF and IL-2 mRNA were not detected in any of the tumor cell lines. However, 1.4 and 3.5 kilobases of the IL-2R mRNA were expressed in the PH101 cells, but not in the other five cell lines. Furthermore, IL-2R was detected on the cell surface of the PH101 cells by the flow-cytometric analysis with an anti-IL-2R monoclonal antibody. Interestingly, the soluble IL-2R (sIL-2R) was found in the conditioned media obtained from the PH101 cell culture with a sandwich enzyme immunoassay. Moreover, the sIL-2R secreted from the PH101 cells blocked the IL-2 dependent lymphocyte proliferation. These results indicate that the expression of IL-2R on PH101 might suppress the IL-2 induced lymphocyte proliferation.