Down-regulation of nestin in mesenchymal stem cells derived from peripheral blood through blocking bone morphogenesis pathway

Different signaling pathways are implicated in proliferation and differentiation of stem cells. Bone Morphogenesis Pathway (BMP) signaling was known to display an important function in osteogenic and adipogenic differentiation of mesenchymal stem cells (MSCs). In the present study, the authors investigated whether blocking BMP signaling was associated with down regulation of Nestin expression as neural stem cell marker in peripheral blood derived mesenchymal stem cells (PB-MSCs). At first, MSCs were isolated from peripheral blood by plastic adherent ability and flow cytometry analysis. After reaching the confluence, the cells were treated with medium containing Noggin as antagonist of BMP signaling upon 8 days. Real time PCR analysis indicated that the expression of Nestin was diminished in PB-MSCs by attenuating BMP signaling. The obtained results suggested that BMP signaling might have a regulatory function on the Nestin expression in mesenchymal stem cells.     

Applications of nummulitids and other larger benthic foraminifera in depositional environment and sequence stratigraphy: an example from the Eocene deposits in Zagros Basin,SW Iran

The Tale-Zang Formation in Zagros Mountains (south-west Iran) is a Lower to Middle Eocene carbonate sequence. Carbonate sequences of the Tale-Zang Formation consist mainly of large benthic foraminifera (e.g. Nummulites and Alveolina), along with other skeletal and non-skeletal components. Water depth during deposition of the formation was determined based on the variation and types of benthic foraminifera, and other components in different facies. Microfacies analysis led to the recognition of ten microfacies that are related to four facies belts such as tidal flat, lagoon, shoal and open marine. An absence of turbidite deposits, reefal facies, gradual facies changes and widespread tidal flat deposits indicate that the Tale-Zang Formation was deposited in a carbonate ramp environment. Due to the great diversity and abundance of larger benthic foraminifera, this carbonate ramp is referred to as a “foraminifera-dominated carbonate ramp system”. Based on the field observations, microfacies analysis and sequence stratigraphic studies, three third-order sequences in the Langar type section and one third-order sequence in the Kialo section were identified. These depositional sequences have been separated by both type-1 and type-2 sequence boundaries. The transgressive systems tracts of sequences show a gradual upward increase in perforate foraminifera, whereas the highstand systems tracts of sequences contain predominantly imperforate foraminifera.     

Does host plant richness explain diversity of ectomycorrhizal fungi? Re‐evaluation of Gao et al. (2013) data sets reveals sampling effects

The generally positive relationship between biodiversity of groups of directly or indirectly interacting organisms is one of the most important ecological concepts (Gaston, 2000 Nature, 405 , 220–227; Scherber C, Eisenhauer N, Weisser WW et al., 2010 Nature, 468 , 553–556). In a recent issue of Molecular Ecology, Gao C, Shi N‐N, Liu Y‐X et al. (2013: 22 , 3403–3414) reported that the richness of plants and ectomycorrhizal fungi is positively correlated both at local and at global scales. Here, we challenge these findings by re‐analysis of data and ascribe the reported results to sampling effect and poor data compilation.     

Stepwise morphological changes and cytoskeletal reorganization of human mesenchymal stem cells treated by short-time cyclic uniaxial stretch

This study aimed to investigate stepwise remodeling of human mesenchymal stem cells (hMSCs) in response to cyclic stretch through rearrangement and alignment of cells and cytoskeleton regulation toward smooth muscle cell (SMC) fate in different time spans. Image analysis techniques were utilized to calculate morphological parameters. Cytoskeletal reorganization was observed by investigating F-actin filaments using immunofluorescence staining, and expression level of contractile SMC markers was followed by a quantitative polymerase chain reaction method. Applying cyclic uniaxial stretch on cultured hMSCs, utilizing a costume-made device, led to alteration in fractal dimension (FD) and cytoskeleton structure toward continuous alignment and elongation of cells by elevation of strain duration. Actin filaments became more aligned perpendicular to the axis of mechanical stretch by increasing uniaxial loading duration. At first, FD met a significant decrease in 4 h loading duration then increased significantly by further loading up to 16 h, followed by another decrease up to 1 d of uniaxial stretching. HMSCs subjected to 24 h cyclic uniaxial stretching significantly expressed early and intermediate contractile SM markers. It was hypothesized that the increase in FD after 4 h while cells continuously became more aligned and elongated was due to initiation of change in phenotype that influenced arrangement of cells. At this point, change in cell phenotype started leading to change in morphology while mechanical loading still caused cell alignment and rearrangement. Results can be helpful when optimized engineered cells are needed based on mechanical condition for functional engineered tissue and cell therapy.     

Receptor modification as a therapeutic approach against viral diseases

Poliovirus causes flaccid paralysis through the destruction of motor neurons in the CNS. Susceptibility to its infection is mainly due to the interaction in between the surface capsid proteins and its receptors on the host cell surface, important for binding, penetration and other necessary events during early infection. Receptor modification is a new approach to treat viral diseases by the modification of target proteins structure. Binding domains are modified in an effective way to make it difficult for the virus to recognize it. In this study, tolerant and intolerant induced mutations in the poliovirus receptor, VP1 and VP2 were identified and substituted in the seed sequence to get the modified versions. Substitutions causing changes in initial folding were short listed and further analyzed for high level folding, physiochemical properties and interactions. Highest RMSD values were observed in between the seed and the mutant K90F (3.265 Å) and Q130W (3.270Å) respectively. The proposed substitutions were found to have low functional impact and thus can be further tested and validated by the experimental researchers. Interactions analyses proved most of the substitutions having decreased affinity for both the VP1 and VP2 and thus are of significant importance against poliovirus. This study will play an important role for bridging computational biology to other fields of applied biology and also will provide an insight to develop resistance against viral diseases. It is also expected that same approach can also be applicable against other viruses like HCV, HIV and other in near future.     

Kinetic constants for the inhibition of camel retinal acetylcholinesterase by the carbamate insecticide lannate

We have designed this study to determine various kinetic parameters of camel retinal membrane‐bound acetylcholinesterase (AChE; EC 3.1.1.7) inhibition by carbamate insecticide lannate [methyl N‐{{(methylamino)carbonyl}oxy} ethanimidothioate]. All these kinetic constants were derived by simple graphical methods. The value of kinetic parameters was estimated as follows: 0.061 (μM)⁻¹, 1.14 (μM)⁻¹, 0.216 μM, 0.016 min⁻¹, 0.0741 (μM min)⁻¹, 0.746 μM, and 4.42 μM for velocity constant (K_v), new inhibition constant (K_nic), dissociation constant (K_d), carbamylation rate constant (k_2c), overall carbamylation rate constant (k′2 ), 50% inhibition constant (K_I50), and 99% inhibition constant (K_I99), respectively. These unique methods may be used to estimate such kinetic parameters for time‐dependent inhibition of enzymes by variety of chemicals, insecticides, herbicides, and drugs. © 1998 John Wiley & Sons, Inc. J Biochem Toxicol 13: 41–46, 1999