Effect of resveratrol on the radiosensitivity of 5-FU in human breast cancer MCF-7 cells

The aim of this study was to assess the efficacy of resveratrol (Res) on radiosensitivity of 5-fluorouracil (5-FU) in the spheroid culture of MCF-7 breast cancer cell line using colony formation examination. Spheroids on day 9 with 300 µm diameters were treated with 20 µM resveratrol and/or 1 µM 5-FU for one volume doubling time (VDT) (42 hours) and then irradiated with 2 Gy gamma radiation (⁶⁰Co) in various groups. Then the viability of the cells and clonogenic ability were acquired by blue dye exclusion and colony formation assay, respectively. The population doubling time in the monolayer culture and the VDT of spheroid culture was 22.48 0.23 hours and 42 0.63 hours respectively. None of the drugs and combination of them had any effect on the viability of cells. The combination treatment of 5-FU+Res+ radiation significantly reduced the colony formation ability of spheroid cells in comparison with each treatment alone. Our results indicated that resveratrol can significantly decrease colony number of breast cancer spheroid cells treated with 5-FU in combination with gamma-rays. Thus, resveratrol as a hypoxia-inducible factor-1-alpha inhibitor increased the radiosensitization of breast cancer spheroid cells.     

Plant community responses to environmentally friendly piste management in northeast Iran

It is well‐known that pistes have adverse effects on alpine ecosystems. Previous studies urged that pistes should be installed and managed in the ways to minimize negative impacts on natural habitats. However, the impacts of this type of management on the plant communities are not widely studied. The aim of this study was to examine species composition and biodiversity changes in an environmentally friendly managed piste in northeast Iran. This piste has been established in a previously degraded alpine landscape. For the vegetation survey, we sampled 44 within and 28 off‐piste plots. Except for the piste management, other environmental factors were similar between the piste and off‐piste plots. Dominant species were determined, and variation in community composition of the two areas was visualized. Also, native species, phylogenetic, and functional Hill diversity of the two areas were compared. The results showed that there was a moderate differentiation in the species composition of the piste and off‐piste. Two palatable species (i.e., Bupleurum falcatum and Melica persica) were dominant in the piste and were not recorded in the off‐piste. The diversity calculations results showed that the species diversity of the piste was higher than that of the off‐piste. Phylogenetic diversity at the level of frequent and dominant plants showed a similar result. The piste had a higher functional diversity in terms of functional richness, and functional diversity of frequent and dominant plants. Our findings imply, after 10 years, species, phylogenetic, and functional diversity of the piste is significantly improved. Environmentally friendly piste management (EFPM) induced species composition change that led to emerging species that were absent in the off‐piste. We can conclude that EFPM led to restoration of a degraded landscape. Long‐term impacts of EFPM are still unknown, therefore, caution should be undertaken regarding the installation of new environmentally friendly pistes in other areas.     

Effects of livestock grazing on soil,plant functional diversity,and ecological traits vary between regions with different climates in northeastern Iran

Understanding the responses of vegetation characteristics and soil properties to grazing in different precipitation regimes is useful for the management of rangelands, especially in the arid regions. In northeastern Iran, we studied the responses of vegetation to livestock grazing in three regions with different climates: arid, semiarid, and subhumid. In each region, we selected 6–7 pairwise sampling areas of high versus low grazing intensity and six traits of the present species were recorded on 1 m² plots—five grazed and five ungrazed in each area. The overall fertility was compared using the dissimilarity analysis, and linear mixed‐effect models were used to compare the individual fertility parameters, functional diversity indices, and species traits between the plots with high and low grazing intensity and between the climatic regions. Both climate and grazing, as well as their interaction, affected fertility parameters, functional diversity indices, and the representation of species traits. Grazing reduced functional evenness, height of the community, the representation of annuals, but increased the community leaf area. In the subhumid region, grazing also reduced functional richness. Further, grazing decreased the share of annual species in the semiarid region and seed mass in the arid region. Larger leaf area and seed mass, smaller height and lower share of annuals were associated with intensive grazing. Species with large LA and seed mass, lower height and perennials can be therefore presumed to tolerate trampling and benefit from high nutrient levels, associated with intensive grazing. By providing a detailed view on the impacts of overgrazing, this study highlights the importance of protection from grazing as an effective management tool for maintaining the pastoral ecosystems. In general, the composition of plant traits across the pastures of northeastern Iran was more affected by intensive grazing than by the differences in climate.     

Design, synthesis, and anticancer activity of phosphonic acid diphosphate derivative of adenine-containing butenolide and its water-soluble derivatives of paclitaxel with high antitumor activity

Synthesis of adenine derivative of triphosphono-gamma-(Z)-ethylidene-2,3-dimethoxybutenolide 4 was accomplished by treatment of phosphonate 3 with 5-phosphoribosyl 1-pyrophosphate in the presence of 5-phosphoribosyl 1-pyrophosphate synthetase. It was found that triphosphonate 4 functions as an irreversible stoichiometric inactivator of the Escherichia coli ribonucleoside diphosphate reductase (RDPR). Triphosphonate 4 exhibited potent inhibitory activity against murine leukemias (L1210 and P388), breast carcinoma (MCF7), and human T-lymphoblasts (Molt4/C8 and CEM/0) cell lines. Paclitaxel ester derivatives of adenine-containing triphosphono-gamma-(Z)-ethylidene-2,3-dimethoxybutenolide 8-10 were also synthesized. Like triphosphonate 4, compound 8 exhibited inhibitory property toward RDPR. It also induced microtubule assembly similar to paclitaxel (5). The structure of the chlorodiester linker in 8 was found to account for this dual property. After treatment of MCF7 cells with compounds 4, 5, and 8, fluorescence microscope examination demonstrated the presence of nucleus shrinkage or segmentation. Bifunctional prodrug 8 exhibited higher lipophilicity than 4 and higher water-solubility than 5. Pro-dual-drug 8 exhibited more pronounced anticancer activity relative to that of the triphosphonate 4 and paclitaxel (5). In contrast, compound 9, resulting from the linkage of triphosphonate 4 and paclitaxel (5) through a diester unit, was only found to function as a highly water-soluble prodrug for paclitaxel (5). It induced microtubule assembly in vitro, but did not show inhibitory property toward RDPR. On the other hand, compound 10, an aggregate of triphosphonate 4 and paclitaxel (5), neither functioned as an inhibitor of RDPR nor exhibited microtubule assembly stimulating activity in vitro.     

Integrative repair of the meniscus: lessons from in vitro studies

Current therapies for meniscal injury seek to preserve and repair damaged tissue since loss of meniscal tissue is associated with degenerative changes in the joint, ultimately leading to osteoarthritis (OA). After a meniscal tear, the difficulty of integrating juxtaposed meniscal surfaces continues to be an obstacle. In order to determine the local factors that are necessary for successful tissue repair, previous studies have developed in vitro model systems that allow both biological and quantitative biomechanical measures of meniscus repair. Many studies have shown the importance of individual factors in meniscus metabolism, but there is a complex interplay among a variety of factors that influence meniscal healing, including inflammatory cytokines, growth factors, mechanical loading, and zonal differences in cell and tissue properties. In particular, the upregulation of inflammatory cytokines following joint injury appears to have significant catabolic influences on meniscal cell metabolic activity that must be overcome in order to promote repair. In the presence of inflammatory cytokines, such as interleukin-1 (IL-1) or tumor necrosis factor alpha (TNF-alpha), intrinsic meniscal repair in vitro is significantly inhibited. While anabolic growth factors, such as transforming growth factor-beta1 (TGF-beta1), enhance meniscal repair, they cannot completely overcome the IL-1-mediated inhibition of repair. The mechanisms by which these mediators influence meniscal repair, and their interactions with other factors in the microenvironment, such as mechanical loading, remain to be determined. Future studies must address these complex interactions during meniscal healing to ultimately enhance meniscal repair.     

Viscoelastic properties of human mesenchymally-derived stem cells and primary osteoblasts, chondrocytes, and adipocytes

The mechanical properties of single cells play important roles in regulating cell-matrix interactions, potentially influencing the process of mechanotransduction. Recent studies also suggest that cellular mechanical properties may provide novel biological markers, or "biomarkers," of cell phenotype, reflecting specific changes that occur with disease, differentiation, or cellular transformation. Of particular interest in recent years has been the identification of such biomarkers that can be used to determine specific phenotypic characteristics of stem cells that separate them from primary, differentiated cells. The goal of this study was to determine the elastic and viscoelastic properties of three primary cell types of mesenchymal lineage (chondrocytes, osteoblasts, and adipocytes) and to test the hypothesis that primary differentiated cells exhibit distinct mechanical properties compared to adult stem cells (adipose-derived or bone marrow-derived mesenchymal stem cells). In an adherent, spread configuration, chondrocytes, osteoblasts, and adipocytes all exhibited significantly different mechanical properties, with osteoblasts being stiffer than chondrocytes and both being stiffer than adipocytes. Adipose-derived and mesenchymal stem cells exhibited similar properties to each other, but were mechanically distinct from primary cells, particularly when comparing a ratio of elastic to relaxed moduli. These findings will help more accurately model the cellular mechanical environment in mesenchymal tissues, which could assist in describing injury thresholds and disease progression or even determining the influence of mechanical loading for tissue engineering efforts. Furthermore, the identification of mechanical properties distinct to stem cells could result in more successful sorting procedures to enrich multipotent progenitor cell populations.     

The effects of osmotic stress on the viscoelastic and physical properties of articular chondrocytes.

The metabolic activity of chondrocytes in articular cartilage is influenced by alterations in the osmotic environment of the tissue, which occur secondary to mechanical compression. The mechanism by which osmotic stress modulates cell physiology is not fully understood and may involve changes in the physical properties of the membrane or the cytoskeleton. The goal of this study was to determine the effect of the osmotic environment on the mechanical and physical properties of chondrocytes. In isoosmotic medium, chondrocytes exhibited a spherical shape with numerous membrane ruffles. Normalized cell volume was found to be linearly related to the reciprocal of the extracellular osmolality (Boyle van't Hoff relationship) with an osmotically active intracellular water fraction of 61%. In deionized water, chondrocytes swelled monotonically until lysis at a mean apparent membrane area 234 +/- 49% of the initial area. Biomechanically, chondrocytes exhibited viscoelastic solid behavior. The instantaneous and equilibrium elastic moduli and the apparent viscosity of the cell were significantly decreased by hypoosmotic stress, but were unchanged by hyperosmotic stress. Changes in the viscoelastic properties were paralleled by the rapid dissociation and remodeling of cortical actin in response to hypoosmotic stress. These findings indicate that the physicochemical environment has a strong influence on the viscoelastic and physical properties of the chondrocyte, potentially through alterations in the actin cytoskeleton.     

Cultural and physiological characteristics of Stemphylium lycopersici causing leaf blight disease on vegetable crops

During 2011–2012, an extensive leaf spot disease caused by Stemphylium lycopersici was observed on vegetable crops including, tomato, eggplant, pepper and lettuce in major vegetable-growing regions of Malaysia. Four isolates of S. lycopersici obtained from each vegetable crop were used to determine cultural and physiological characteristics. The variations were found in colony colour (pale to light grey or light as well as the brown), texture (cottony or mycelium flat), shape (regular with concentric growth rings or irregular) and pigmentation (yellow or deep red) of the cultures. The optimum temperature for the conidial germination and mean radial growth of the isolates was 25?°C, and the radial growth of the isolates was maximal on V-8 juice agar followed by potato carrot agar. The maximum sporulation of S. lycopersici isolates was observed on V-8 juice agar media under 12/12 h light/darkness photoperiod at 25?°C.