Using human neural crest-derived progenitor cells to investigate osteogenesis: An in vitro study

Human tooth contains a distinct population of neural crest-derived progenitor cells (dNC-PCs) which are known to give rise to specialized daughter cells of an osteogenic lineage. We hypothesised that dNC-PCs could develop into neural crest-derived bone in a self-propagating and extracorporal culture system. Thus, we examined the three-dimensional structure obtained from osteogenic-stimulated dNC-PCs by morphological, biochemical and spectroscopic methods. After the onset of stimulation, cells formed a multilayer with outer cells covering the surface and inner cells secreting a hyaline matrix. With prolonged culture, multilayers contracted and formed a three-dimensional construct which subsequently converted to a calcified mass. Differentiation of progenitor cells was associated with apoptosis. Cell types which survived were smooth muscle actin-positive cells and bone-like cells. The expression of osteoblastic markers and the secretion of a collagenous matrix indicate that the bone cells had acquired their functional phenotype. Furthermore, these cells produced and secreted membrane-bound vesicles into the newly forming matrix. Consequently, an early biomineralized extracellular matrix was found with calcium phosphate deposits being associated with the newly formed collagen matrix framework. The molar calcium–phosphorus-ratio of the mineralized collagen indicated that amorphous calcium phosphate was present within this matrix. The data suggest that stimulated cultures of dNC-PCs are able to recapitulate some processes of the early phase of osteogenesis.     

Effects of river ice on riparian vegetation

1. Many rivers and streams experience pronounced ice dynamics caused by the formation of anchor and frazil ice, leading to flooding and disturbance of riparian and aquatic communities. However, the effects of dynamic ice conditions on riverine biota are little known. 2. We studied the formation of anchor ice in natural streams over 2 years and assessed the effects of anchor ice on riparian vegetation by comparing sites with frequent or abundant and little or no anchor ice formation. We also studied the direct impact of ice on riparian plants by experimentally creating ice in the riparian zone over three winters and by exposing plants of different life forms to ?18 °C cold ice in the laboratory. 3. Riparian species richness per 1‐m² plot was higher at sites affected by anchor ice than at sites where anchor ice was absent or rare, whereas dominance was lower, suggesting that disturbance by ice enhances species richness. Species composition was more homogenous among plots at anchor ice sites. By experimentally creating riparian ice, we corroborated the comparative results, with species richness increasing in ice‐treated plots compared to controls, irrespective of whether the sites showed natural anchor ice. 4. Because of human alterations of running waters, the natural effects of river ice on stream hydrology, geomorphology and ecology are little known. Global warming in northern streams is expected to lead to more dynamic ice conditions, offering new challenges for aquatic organisms and river management. Our results should stimulate new research, contributing to a better understanding of ecosystem function during winter.     

T cells from indolent CLL patients prevent apoptosis of leukemic B cells in vitro and have altered gene expression profile

T cells may have a role in sustaining the leukemic clone in chronic lymphocytic leukemia (CLL). In this study, we have examined the ability of T cells from CLL patients to support the survival of the leukemic B cells in vitro. Additionally, we compared global gene expression of T cells from indolent CLL patients with healthy individuals and multiple myeloma (MM) patients. Apoptosis of purified leukemic B cells was inhibited in vitro when co-cultured with increasing numbers of autologous T cells (p < 0.01) but not autologous B and T cells of normal donors. The anti-apoptotic effect exceeded that of the anti-apoptotic cytokine IL-4 (p = 0.002) and was greater with CD8+ cells (p = 0.02) than with CD4+ cells (p = 0.05). The effect was depended mainly on cell–cell contact although a significant effect was also observed in transwell experiments (p = 0.05). About 356 genes involved in different cellular pathways were deregulated in T cells of CLL patients compared to healthy individuals and MM patients. The results of gene expression profiling were verified for 6 genes (CCL4, CCL5 (RANTES), XCL1, XCL2, KLF6, and TRAF1) using qRT–PCR and immunoblotting. Our results demonstrate that CLL-derived T cells can prevent apoptosis of leukemic B cells and have altered expression of genes that may facilitate the survival of the leukemic clone.     

Assessing the influence of cycloastragenol on telomere/telomerase system of Arabidopsis thaliana

Plant Cell, Tissue and Organ Culture (PCTOC) - Cycloastragenol (CAG) is a triterpenoid saponin compound that is synthesized by Astragalus species. CAG has many bioactivity, including telomerase...     

Studies on hydrazone derivatives as antifungal agents

The increasing clinical importance of drug-resistant fungal pathogens has urged additional need to fungal research and new antifungal compound development. For this purpose, some N-(1-benzyl-2-phenylethylidene)-N′-[4-(aryl)thiazol-2-yl]hydrazone (1a-e) and N-(1-phenylbutylidene)-N′-[4-(aryl)thiazol-2-yl]hydrazone (2a-e) derivatives were synthesised and evaluated for antifungal activity. Their antifungal activities against standard and clinical strands of Candida albicans, Candida glabrata, Candida utilis, Candida tropicalis, Candida krusei, Candida zeylanoides, and Candida parapsilosis were investigated. A significant level of activity was observed.     

Antimicrobial activity studies on some piperidine and pyrrolidine substituted halogenobenzene derivatives

The in vitro antibacterial and antifungal activities of the compounds synthesised from some 1,2,3,5-tetrahalogeno benzenes in presence of sodium piperidide and sodium pyrrolidide (2,6-dipiperidino-1,4-dihalogenobenzenes; 2,6-dipyrrolidino-1,4-dibromobenzene; 2,4,6-tripyrrolidino chlorobenzene; and 1,3-dipyrrolidino benzene) were investigated. The in vitro antimicrobial activities were screened against the standard strains: Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633 as Gram positive, Yersinia enterocolitica ATCC 1501, Escherichia coli ATCC 11230 and Klebsiella pneumoniae as Gram negative, and Candida albicans as yeast-like fungus. Compounds (3, 5, 6, 7) inhibited the growth of all the test strains at MIC values of 32–512 μg/ml. None of the four compounds (1, 2, 4, 8) studied showed antimicrobial activity against any of the test strains within the MIC range 0.25–512 μg/ml.     

Resistance and bioaccumulation of Cd2+, Cu2+, Co2+ and Mn2+ by thermophilic bacteria, Geobacillus thermantarcticus and Anoxybacillus amylolyticus

In this study, bioaccumulation and heavy metal resistance of Cd²⁺, Cu²⁺, Co²⁺ and Mn²⁺ ions by thermophilic Geobacillus thermantarcticus and Anoxybacillus amylolyticus was investigated. The bacteria, in an order with respect to metal resistance from the most resistant to the most sensitive, was found to be Mn²⁺ > Co²⁺ > Cu²⁺ > Cd²⁺ for both G. thermantarcticus and A. amylolyticus. It was determined that the highest metal bioaccumulation was performed by A. amylolyticus in Mn²⁺ (28,566 μg/g dry weight), and the lowest metal bioaccumulation was performed by A. amylolyticus in Co²⁺ (327.3 μg/g dry weight). The highest Cd²⁺ capacities of dried cell membrane was found to be 36.07 and 39.55 mg/g membrane for G. thermantarticus and A. amylolyticus, respectively, and the highest Cd²⁺ capacities of wet cell membrane was found to be 14.36 and 12.39 mg/g membrane for G. thermantarcticus and A. amylolyticus, respectively.