ABSTRACT
The effects of overexpression of Rubisco activase on photosynthesis were studied in transgenic rice expressing barley or maize Rubisco activase. Immunoblot and SDS-PAGE analyses showed that transgenic lines from both gene constructs expressed the foreign Rubisco activase at high levels. The activation state of Rubisco in transgenic lines was slightly higher than that in non-transgenic plants (NT). In addition, light activation of Rubisco was significantly more rapid in transgenic lines compared with NT. These findings indicate that the overexpression of Rubisco activase can enhance Rubisco activation. However, despite enhanced activation of Rubisco in these transgenic plants, the CO(2) assimilation rate at ambient CO(2) conditions was decreased. This decrease in CO(2) assimilation rate was observed in both young developing and mature leaves independent of nitrogen nutrition. The contents of nitrogen and Chl did not differ significantly between transformants and NT; however, Rubisco content was substantially decreased in transgenic lines. There was no evidence for reduced transcription of RbcS or RbcL in these transgenic lines; in fact, transcript levels were marginally increased compared with NT. These results indicate that the overexpression of Rubisco activase leads to a decrease in Rubisco content, possibly due to post-transcriptional mechanisms.
Subject(s)
Carbon Dioxide/metabolism , Oryza/enzymology , Photosynthesis , Plant Leaves/enzymology , Plant Proteins/metabolism , Ribulose-Bisphosphate Carboxylase/metabolism , Chlorophyll/metabolism , Electrophoresis, Polyacrylamide Gel , Enzyme Activation , Gene Expression Regulation, Plant , Genes, Plant , Light , Nitrogen/metabolism , Oryza/genetics , Oryza/radiation effects , Plant Leaves/genetics , Plant Leaves/radiation effects , Plant Proteins/genetics , Plants, Genetically Modified/enzymology , Plants, Genetically Modified/genetics , Ribulose-Bisphosphate Carboxylase/genetics , Transcription, Genetic , Up-RegulationABSTRACT
Increased expression of heparin-binding epidermal growth factor-like growth factor (HB-EGF) is frequently observed in certain cancers such as ovarian and breast cancers, and this protein is a desirable target for drug delivery by a drug delivery system (DDS). In the present study, we developed novel immunoliposomes targeting HB-EGF for cancer therapy. The immunoliposomes significantly associated with Vero-H cells overexpressing HB-EGF compared with their binding to wild-type Vero cells, whereas liposomes without modification by the antibody did not associate with either type of cells. Moreover, enhanced uptake of the immunoliposomes into Vero-H cells was observed as well as that into MDA-MB-231 human breast cancer cells, which are known to highly express HB-EGF. These results suggest that HB-EGF mediates the binding and uptake of the immunoliposomes in HB-EGF-expressing cells. Next, we determined the therapeutic effect of these immunoliposomes encapsulating an anticancer drug on tumor-bearing mice. For this purpose, we prepared doxorubicin (DOX)-encapsulated immunoliposomes and injected them intravenously into mice bearing MDA-MB-231 cancer cells. As a result, these DOX-encapsulated immunoliposomes suppressed not only tumor progression but also tumor regression. In conclusion, our results indicate that anti-HB-EGF antibody-modified liposomes could be a useful DDS carrier for the treatment of HB-EGF-expressing cancers.
Subject(s)
Antibiotics, Antineoplastic/administration & dosage , Doxorubicin/administration & dosage , Drug Carriers/chemistry , Immunoglobulin G , Intercellular Signaling Peptides and Proteins/metabolism , Mammary Neoplasms, Experimental/drug therapy , Animals , Antibiotics, Antineoplastic/therapeutic use , Blotting, Western , Cell Proliferation/drug effects , Chlorocebus aethiops , Doxorubicin/therapeutic use , Female , Heparin-binding EGF-like Growth Factor , Humans , Immunoglobulin Fab Fragments/chemistry , Immunoglobulin Fab Fragments/immunology , Immunoglobulin G/chemistry , Immunoglobulin G/immunology , Intercellular Signaling Peptides and Proteins/biosynthesis , Liposomes , Mammary Neoplasms, Experimental/immunology , Mice , Mice, Inbred BALB C , Mice, Nude , Protein Binding , Real-Time Polymerase Chain Reaction , Vero Cells , Xenograft Model Antitumor AssaysABSTRACT
The present study was carried out to investigate development of recipient chicken embryonic reproductive tracts which are transferred chicken primordial germ cells (PGCs). It is thought that differentiation of PGCs is affected by the gonadal somatic cells. When female PGCs are transferred to male embryos, it is possible that they differentiate to W-spermatogonia. However, the relationship development between PGCs and gonads has not been investigated. At stage 12-15 of incubation of fertilized eggs, donor PGCs, which were taken from the blood vessels of donor embryos, were injected into the blood vessels of recipient embryos. The gonads were removed from embryos that died after 16 days of incubation and from newly hatched chickens and organs were examined for morphological and histological features. The survival rate of the treated embryos was 13.6% for homo-sexual transfer of PGCs (male PGCs to male embryo or female PGCs to female embryo) and 28.9% for hetero-sexual transfer PGCs (male PGCs to female embryo or female PGCs to male embryo) when determined at 15 days of incubation. The gonads of embryos arising from homo-sexual transfer appeared to develop normally. In contrast, embryos derived from hetero-sexual transfer of PGCs had abnormal gonads as assessed by histological observation. These results suggest that hetero-sexual transfer of PGCs may influence gonadal development early-stage embryos.
ABSTRACT
Bisphosphonates such as alendronate have been developed as antiresorptive agents capable of treating diseases related to bone remodeling. In the present study, we examined the effect of alendronate on the healing of acetic acid-induced gastric ulcers in rats and investigated the mechanism involved in this action both in vivo and in vitro using the rat gastric epithelial cell line (RGM1). Acetic acid-induced gastric ulcers healed spontaneously, with up-regulation of COX-2/prostaglandin E2 production as well as expression of vascular endothelium-derived growth factor (VEGF) and basic fibroblast growth factor (bFGF) in ulcerated mucosa. The healing of ulcers was impaired by indomethacin (2 mg/kg, s.c.) or alendronate (60 mg/kg, p.o.) given once daily for 7 days, starting 3 days after acid application. Indomethacin, but not alendronate, inhibited mucosal prostaglandin E2 production. Alendronate as well as indomethacin decreased the protein expression of both VEGF and bFGF in ulcerated mucosa, resulting in a reduction of angiogenesis in the ulcer base. Supplementation of recombinant bFGF significantly reverted the delay in ulcer healing caused by alendronate. On the other hand, the size of cell-free areas in RGM1 cells in vitro decreased with time after wound induction, and this process was promoted by epidermal growth factor (EGF; 10 ng/ml). Co-incubation with alendronate (1 mM) did not affect the spontaneous healing but significantly suppressed the accelerated wound healing caused by EGF. These results suggest that alendronate impairs the healing of gastric ulcers in rats, and this effect may be related to down-regulation of VEGF and bFGF, the important growth factors for vascularization/granulation, as well as suppression of the stimulatory action of EGF on epithelial proliferation/migration.
