Cryopreservation of somatic embryos of the herbaceous peony (Paeonia lactiflora Pall.) by air drying

This study was carried out to establish a suitable method for the cryopreservation of somatic embryos of the herbaceous peony. The somatic embryos were obtained from cotyledon and anther cultures on a MS medium supplemented with abscisic acid (ABA) and phenylacetic acid (PAA), respectively. The frequency of somatic embryo formation was the greatest (61%) from the cotyledons cultured on a MS medium supplemented with 1.0 mg l(-1) of ABA. Embryos were also obtained directly from anthers cultured on a MS medium with or without 2.0 mg l(-1) of PAA. For the cryopreservation of peony somatic embryos, the embryos were dried under a stream of sterile air and frozen by immersion in liquid nitrogen. Thawed embryos were germinated into plantlets after placing on a medium containing 0.3 mg l(-1) of gibberellic acid (GA(3)). The frequency of the post-thaw regrowth of cryopreserved somatic embryos was related to their size and desiccation time, the latter ranging from 0 to 2 h. When the somatic embryos were desiccated for 1 h, the frequency of post-thaw regrowth was greater than 66%. The frequency of post-thaw regrowth of the cryopreserved somatic embryos from anthers and cotyledon tissues was generally high when they were 2-3 mm in size. Desiccation may be a suitable method for the cryopreservation of somatic embryos of the herbaceous peony.     

Enhancement of carbon dioxide fixation by alteration of illumination duringChlorella vulgaris-Buitenzorg's growth

Alteration of illumination with optimum carbon dioxide fixation-based curve in this research successfully enhanced the CO₂-fixation (q_co2) capability ofChlorella vulgaris Buitenzorg cultivated in a bubble column photo bioreactor. The level of CO₂ fixation was up to 1.91 times that observed from cultivation with intensification of illumination on an optimum growth-based curve. During 144 h of cultivation, alteration of light intensity on an optimum CO₂-fixation-based curve produced a q_CO2 of 6.68 h^?1. Increases in light intensity based on a curve of optimum CO₂-fixation produced a final cell concentration of about 5.78 g/L. Both cultivation methods were carried out under ambient pressure at a temperature of 29°C with a superficial gas velocity of 2.4 m/h (U_G). Cells were grown on Beneck medium in a 1.0 L Bubble Column Photo bioreactor illuminated by aPhillips Halogen Lamp (20 W/12 V/50 Hz). The inlet gas had a carbon dioxide content of 10%.     

Evolution of ribosomal DNA-derived satellite repeat in tomato genome

Background  

Tandemly repeated DNA, also called as satellite DNA, is a common feature of eukaryotic genomes. Satellite repeats can expand and contract dramatically, which may cause genome size variation among genetically-related species. However, the origin and expansion mechanism are not clear yet and needed to be elucidated.     

A Distinct Macrophage Population Mediates Metastatic Breast Cancer Cell Extravasation,Establishment and Growth

Background

The stromal microenvironment and particularly the macrophage component of primary tumors influence their malignant potential. However, at the metastatic site the role of these cells and their mechanism of actions for establishment and growth of metastases remain largely unknown.

Methodology/Principal Findings

Using animal models of breast cancer metastasis, we show that a population of host macrophages displaying a distinct phenotype is recruited to extravasating pulmonary metastatic cells regardless of species of origin. Ablation of this macrophage population through three independent means (genetic and chemical) showed that these macrophages are required for efficient metastatic seeding and growth. Importantly, even after metastatic growth is established, ablation of this macrophage population inhibited subsequent growth. Furthermore, imaging of intact lungs revealed that macrophages are required for efficient tumor cell extravasation.

Conclusion/Significance

These data indicate a direct enhancement of metastatic growth by macrophages through their effects on tumor cell extravasation, survival and subsequent growth and identifies these cells as a new therapeutic target for treatment of metastatic disease.     

c-Cbl acts as a mediator of Src-induced activation of the PI3K-Akt signal transduction pathway during TRAIL treatment

We have previously observed that TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) induces acquired TRAIL resistance by increasing Akt phosphorylation and Bcl-xL expression. In this study, we report that Src, c-Cbl, and PI3K are involved in the phosphorylation of Akt during TRAIL treatment. Data from immunoprecipitation and immunoblotting assay reveal that Src interacts with c-Cbl and PI3K. Data from immune complex kinase assay demonstrate that Src can directly phosphorylate c-Cbl and PI3K p85 subunit protein. Data from gene knockdown experiments with an RNA interference (RNAi) technique show that c-Cbl is involved in the interaction between Src and PI3K p85 during TRAIL treatment, playing an important role in TRAIL-induced Akt phosphorylation. Taken together, c-Cbl may act as a mediator to regulate the Src-PI3K-Akt signal transduction pathway during TRAIL treatment.     

Varied patterns of DNA methylation change between different satellite regions in bovine preimplantation development

Global reduction of DNA methylation, a part of genome reprogramming processes, occurs in a gradual manner until before implantation and is recognized as a conserved process in mammals. Here, we reported that in bovine, satellite regions exhibited varied patterns of methylation changes when one-cell egg advanced to the blastocyst; a maintenance methylation was observed in satellite I sequences, a decrease in alpha satellites, and an increase in satellite II regions. Cloned embryos exhibited similar changes for DNA methylation in the satellite I and alpha. We also observed that the satellite I and alpha sequences were methylated more in inner cell mass region of the blastocyst whereas the satellite II showed selective demethylation in this region. Together, these findings point that individual satellite sequences carry their own methylation patterns under the pressure of global demethylation, suggesting that local methylation control system acts on the satellite regions in early bovine embryos.     

Interaction of profilin‐1 and F‐actin via a β‐arrestin‐1/JNK signaling pathway involved in prostaglandin E2‐induced human mesenchymal stem cells migration and proliferation

Although many previous reports have examined the function of prostaglandin E₂ (PGE₂) in the migration and proliferation of various cell types, the role of the actin cytoskeleton in human mesenchymal stem cells (hMSCs) migration and proliferation has not been reported. The present study examined the involvement of profilin‐1 (Pfn‐1) and filamentous‐actin (F‐actin) in PGE₂‐induced hMSC migration and proliferation and its related signal pathways. PGE₂ (10^?6 M) increased both cell migration and proliferation, and also increased E‐type prostaglandin receptor 2 (EP2) mRNA expression, β‐arrestin‐1 phosphorylation, and c‐Jun N‐terminal kinase (JNK) phosphorylation. Small interfering RNA (siRNA)‐mediated knockdown of β‐arrestin‐1 and JNK (‐1, ‐2, ‐3) inhibited PGE₂‐induced growth of hMSCs. PGE₂ also activated Pfn‐1, which was blocked by JNK siRNA, and induced F‐actin level and organization. Downregulation of Pfn‐1 by siRNA decreased the level and organization of F‐actin. In addition, specific siRNA for TRIO and F‐actin‐binding protein (TRIOBP) reduced the PGE₂‐induced increase in hMSC migration and proliferation. Together, these experimental data demonstrate that PGE₂ partially stimulates hMSCs migration and proliferation by interaction of Pfn‐1 and F‐actin via EP2 receptor‐dependent β‐arrestin‐1/JNK signaling pathways. J. Cell. Physiol. 226: 559–571, 2011. © 2010 Wiley‐Liss, Inc.     

H-Y antigen in X,i(Xq) gonadal dysgenesis: Evidence of X-linked genes in testicular differentiation

Summary Three years ago, we detected H-Y antigen in the white blood cells of a phenotypic female with several of the stigmata of Turner's syndrome, and the mosaic karyotype: 45,X/46,X,i(Xq). We surmised at the time that the isochromosome, i(Xq), may have contained occult Y-chromosome-derived material. We have now confirmed the presence of H-Y in this patient and we have obtained evidence for the presence of H-Y in four of five other similar patients, all of whom are notable for carrying at least a single cell line with the karyotype 46,X,i(Xq). Although we cannot categorically exclude the presence of Y-chromosomal genes in the cells of these patients, there is no cytogenetic evidence of structural rearrangement involving the Y in any of the cases. Expression of H-Y antigen in association with i(Xq) thus implies that H-Y structural genes are X-situated, or alternatively that they are autosomal and X-regulated. It would follow that the H-Y⁺ cellular phenotype per se is not a valid marker for the Y-chromosome, and that H-Y genes that have been mapped to the pericentric region of the Y may be regulatory.     

Two enzymes in one; two yeast peroxiredoxins display oxidative stress-dependent switching from a peroxidase to a molecular chaperone function

Although a great deal is known biochemically about peroxiredoxins (Prxs), little is known about their real physiological function. We show here that two cytosolic yeast Prxs, cPrxI and II, which display diversity in structure and apparent molecular weights (MW), can act alternatively as peroxidases and molecular chaperones. The peroxidase function predominates in the lower MW forms, whereas the chaperone function predominates in the higher MW complexes. Oxidative stress and heat shock exposure of yeasts causes the protein structures of cPrxI and II to shift from low MW species to high MW complexes. This triggers a peroxidase-to-chaperone functional switch. These in vivo changes are primarily guided by the active peroxidase site residue, Cys(47), which serves as an efficient "H(2)O(2)-sensor" in the cells. The chaperone function of these proteins enhances yeast resistance to heat shock.     

Hypoglycemic effects of exopolysaccharides produced by mycelial cultures of two different mushrooms Tremella fuciformis and Phellinus baumii in ob/ob mice

The anti-diabetic activities of the exopolysaccharides (EPS) produced by submerged mycelial culture of two different mushrooms, Tremella fuciformis and Phellinus baumii, in ob/ob mice were investigated. All the animals were randomly divided into three groups with seven animals in each group: The control group received 0.9% NaCl solution; the diabetic groups were treated with EPS from T. fuciformis (Tf EPS) and P. baumii (Pb EPS) at the level of 200 mg/kg body weight using an oral zoned daily for 52 days. The plasma glucose levels in the EPS-fed mice were substantially reduced by about 52% (Tf EPS) and 32% (Pb EPS), respectively, as compared to control mice. The results of oral glucose tolerance test (OGTT) revealed that both EPS-fed groups significantly increased the glucose disposal after 52 days of EPS treatments. Furthermore, higher food efficiency ratios and reduced blood triglyceride levels were observed in the EPS-treated groups. Because peroxisome proliferator-activated receptor gamma (PPAR-γ) is indeed a key regulator of insulin action, we investigated the expression pattern of adipose tissue PPAR-γ messenger RNA (mRNA) and plasma levels of PPAR-γ. It was revealed that PPAR-γ was significantly activated in response to EPS treatments. The results suggested that both EPS exhibited considerable hypoglycemic effect and improved insulin sensitivity possibly through regulating PPAR-γ-mediated lipid metabolism. Our results indicated that two mushroom-derived EPS might be developed as potential oral hypoglycemic agents or functional foods for the management of non-insulin-dependent diabetes mellitus.