A herbivore-induced homoterpene volatile is emitted from Basella alba leaves.

An irregular C11 homoterpene, (E)-4,8-dimethylnona-1,3,7-triene (DMNT) was identified as a major component of the volatile compounds emitted from Basella alba leaves induced by herbivore. The terpenes including DMNT were not detected from the leaves infected by Botrytis cinerea. These results suggested that volatile emission from B. alba leaves was induced by herbivory but not by a fungal infection.

Electrostatic interaction of positive charges on the surface of Psb31 with photosystem II in the diatom Chaetoceros gracilis.

Psb31, a novel extrinsic protein found in diatom photosystem II (PSII), directly binds to PSII core subunits, independent of the other extrinsic proteins, and functions to maintain optimum oxygen evolution. However, how Psb31 electrostatically interacts with PSII intrinsic proteins remains to be clarified. In this study, we examined electrostatic interaction of Psb31 with PSII complexes isolated from the diatom Chaetoceros gracilis. Positive or negative charges of isolated Psb31 proteins were modified with N-succinimidyl propionate (NSP) or glycine methyl ester (GME), respectively, resulting in formation of uncharged groups. NSP-modified Psb31 did not bind to PSII with a concomitant increase in NSP concentration, whereas GME-modified Psb31 clearly bound to PSII with retention of oxygen-evolving activity, indicating that positive charges of Lys residues and the N-terminus on the surface of Psb31 are involved in electrostatic interactions with PSII intrinsic proteins. Mass spectrometry analysis of NSP-modified Psb31 and sequence comparisons of Psb31 from C. gracilis with other chromophyte algae led to identification of three Lys residues as possible binding sites to PSII. Based on these findings, together with our previous cross-linking study in diatom PSII and a red algal PSII structure, we discuss binding properties of Psb31 with PSII core proteins.

Organocatalytic enantioselective decarboxylative reaction of malonic acid half thioesters with cyclic N-sulfonyl ketimines by using N-heteroarenesulfonyl cinchona alkaloid amides.

The organocatalytic enantioselective decarboxylative Mannich reaction of malonic acid half thioesters (MAHTs) with cyclic N-sulfonyl ketimines by using N-heteroarenesulfonyl cinchona alkaloid amides afforded products with high enantioselectivity. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts. The reaction proceeds through a nucleophilic addition of the MAHTs to the ketimines prior to decarboxylation.

Alpha 1 antitrypsin activity is decreased in human amnion in premature rupture of the fetal membranes.

Preterm premature rupture of the membranes (PPROM) has been considered to be closely associated with chorioamnionitis. However, the detailed mechanism is not well understood. Alpha 1 antitrypsin (AAT) was reported to decrease in concentration in amniotic fluid obtained from patients with PPROM. However, the origin of AAT in amniotic fluid has not been clarified. In this study, we assessed the expression and localization of AAT in human amnion, as well as its biological activity in cases with PROM. Human amniotic epithelial (hAE) cells expressed AAT. After stimulation with oncostatin M (OSM), interleukin-6 (IL-6) or tumor necrotic factor alpha (TNF alpha), hAE cells increased the expression of AAT, while the expression of MMP9 was reduced by OSM and induced by TNF alpha. Oxidized AAT (inactivated form) was detected in the amnion with PPROM and TPROM, but not in specimens without PROM. Moreover, AAT activity was decreased in amnions from cases with PROM, regardless of gestational age. Thus, the results showed that AAT in the amnion may function as a protective shield at inflammatory sites, and not as it loses it inhibitory activity in cases with PROM, possibly by oxidation, suggesting that its imbalance contributes to PROM.

Characterization of laminin isoforms in human amnion.

Epithelial cells of the human amnion have been reported to possess similar functions to many types of cells, such as hepatocytes, neurons, and pancreatic beta-cells. We reported previously that one of the hepatocyte-like functions of human amniotic epithelial cells was reinforced by the presence of basement membrane components. Laminin is one of the main components of the basement membrane; it critically contributes to cell differentiation. Laminin has several heterotrimer isoforms composed of an alpha-, a beta-, and a gamma-chain, and each type of chain has several types of subunit chains: alpha1-5, beta1-3, and gamma1-3. In this study, we characterized the laminin subunit chains in human amnion. Laminin is produced and secreted from adjacent epithelial cells, and therefore, the gene expression of laminin subunit chains in human amniotic epithelial cells was investigated by RT-PCR. Their localization was examined by immunohistochemical staining of frozen sections. The findings suggested that the basement membrane of the human amnion contains a broad spectrum of laminin isoforms, laminin-2, -4, -5, -6, -7, -10, -11. These findings will provide clues not only for understanding the physiological roles of the amnion and hAECs, but also for applying this tissue as a source of donor cells for cell transplantation therapy.

Expression of the mitogen-inducible gene-2 (mig-2) is elevated in human uterine leiomyomas but not in leiomyosarcomas.

To investigate the role of a recently cloned cell proliferation-related gene, mig-2 (mitogen-inducible gene-2), in the growth of uterine leiomyomas, this gene's expression at mRNA and protein levels was examined in normal myometrium, leiomyomas, and leiomyosarcomas of the uterus. Northern blotting, Western blotting, and immunohistochemical staining demonstrated that mig-2 expression was increased in leiomyomas compared with normal myometrium, especially during the secretory phase of the menstrual cycle. In contrast, the mig-2 expression was greatly decreased in leiomyosarcomas. Direct sequencing of the whole coding region of mig-2 cDNA and Southern blotting revealed that mig-2 alterations, such as mutations, rearrangement, and amplification, were not present in either leiomyomas or leiomyosarcomas. These findings suggest that mig-2 expression is transcriptionally elevated in leiomyomas and could be involved in its hormone-mediated growth of leiomyomas of the uterus.

Establishment of immortalized human amniotic mesenchymal stem cells.

Human amniotic mesenchymal cells (HAM cells) are known to contain somatic stem cells possessing the characteristics of pluripotency. However, little is known about the biology of these somatic cells because isolated HAM cells from amniotic membrane have a limited lifespan. To overcome this problem, we attempted to prolong the lifespan of HAM cells by infecting retrovirus encoding human papillomavirus type16E6 and E7 (HPV16E6E7), bmi-1, and/or human telomerase reverse transcriptase (hTERT) genes and investigated their characteristics as stem cells. We confirmed the immortalization of the four lines of cultured HAM cells for about 1 year. Immortalized human amnion mesenchymal cells (iHAM cells) have continued to proliferate over 200 population doublings (PDs). iHAM cells were positive for CD73, CD90, CD105, and CD44 and negative for CD34, CD14, CD45, and HLA-DR. They expressed stem cell markers such as Oct3/4, Sox2, Nanog, Klf4, SSEA4, c-myc, vimentin, and nestin. They showed adipogenic, osteogenic, and chondrogenic differentiation abilities after induction. These results suggested that immortalized cell lines with characteristics of stem cells can be established. iHAM cells with an extended lifespan can be used to produce good experimental models both in vitro and in vivo.

Human amniotic mesenchymal cells differentiate into chondrocytes.

Recently, cartilage diseases have been treated by auto- or allogenic chondrocyte transplantation. However, such treatments are limited by the necessity of having a large amount of cells for transplantation, the risk of rejection, and donor shortage. Since the human amnion is immune-privileged tissue suitable for allotransplantation, the potential of human amniotic mesenchymal cells (HAMc) to differentiate into chondrocytes was assessed. The expression of gene encoding transcription factors SOXs and bone morphogenetic proteins (BMPs) as well as BMP receptors were assessed. Chondrocyte phenotype was characterized by positive expression of the cartilage marker genes collagen type II and aggrecan by RT-PCR, collagen type II protein were analyzed by immunofluorescence analysis. HAMc expressed chondrocyte-related genes, including SOXs, BMPs, as well as BMP receptors. Collagen type II and aggrecan were detected after the induction of chondrogenesis with BMP-2. HAMc, transplanted into noncartilage tissue of mice with BMP-2, or implanted with collagen-scaffold into the defects generated in a rat's bone, underwent morphological changes with deposition of collagen type II. These results showed that HAMc have the potential to differentiate into chondrocytes in vitro and in vivo, suggesting that they have therapeutic potential for the treatment of damaged or diseased cartilage.

The potential of amniotic membrane/amnion-derived cells for regeneration of various tissues.

Regenerative medicine is a new field based on the use of stem cells to generate biological substitutes and improve tissue functions, restoring damaged tissue with high proliferability and differentiability. It is of interest as a potential alternative to complicated tissue/organ transplantation. Recently, amnion-derived cells have been reported to have multipotent differentiation ability, and these cells have attracted attention as a cell source for cell-transplantation therapy. The amnion possesses considerable advantageous characteristics: the isolated cells can differentiate into all three germ layers; they have low immunogenicity and anti-inflammatory functions; and they do not require the sacrifice of human embryos for their isolation, thus avoiding the current controversies associated with the use of human embryonic stem cells. Moreover, we developed human amniotic cell-sheets using a novel culture surface coated with a noncytotoxic, temperature-responsive elastic protein-based polymer. We also generated a "hyper-dry-amnion", which has already been applied clinically in the ophthalmological field. Compared to cryopreserved fresh amnion, "hyper-dry-amnion" is easy to handle and has started to bring good results to patients. These materials from the amnion are also expected to open a new field in tissue engineering. Thus, amnion, which had been discarded after parturition, has started to be appreciated as an attractive material in the field of regenerative medicine. In this review, the most recent and relevant clinical and experimental data about the use of amniotic membrane and cells derived from it are described.