Genetic interactions reveal the antagonistic roles of FT/TSF and TFL1 in the determination of inflorescence meristem identity in Arabidopsis

During the transition to the reproductive phase, the shoot apical meristem switches from the developmental program that generates vegetative organs to instead produce flowers. In this study, we examined the genetic interactions of FLOWERING LOCUS T (FT)/TWIN SISTER OF FT (TSF) and TERMINAL FLOWER 1 (TFL1) in the determination of inflorescence meristem identity in Arabidopsis thaliana. The ft‐10 tsf‐1 mutants produced a compact inflorescence surrounded by serrated leaves (hyper‐vegetative shoot) at the early bolting stage, as did plants overexpressing TFL1. Plants overexpressing FT or TSF (or both FT and TFL1) generated a terminal flower, as did tfl1‐20 mutants. The terminal flower formed in tfl1‐20 mutants converted to a hyper‐vegetative shoot in ft‐10 tsf‐1 mutants. Grafting ft‐10 tsf‐1 or ft‐10 tsf‐1 tfl1‐20 mutant scions to 35S::FT rootstock plants produced a normal inflorescence and a terminal flower in the scion plants, respectively, although both scions showed similar early flowering. Misexpression of FT in the vasculature and in the shoot apex in wild‐type plants generated a normal inflorescence and a terminal flower, respectively. By contrast, in ft‐10 tsf‐1 mutants the vasculature‐specific misexpression of FT converted the hyper‐vegetative shoot to a normal inflorescence, and in the ft‐10 tsf‐1 tfl1‐20 mutants converted the shoot to a terminal flower. TFL1 levels did not affect the inflorescence morphology caused by FT/TSF overexpression at the early bolting stage. Taking these results together, we proposed that FT/TSF and TFL1 play antagonistic roles in the determination of inflorescence meristem identity, and that FT/TSF are more important than TFL1 in this process.     

Comparative cellular and molecular analyses of pooled bone marrow multipotent mesenchymal stromal cells during continuous passaging and after successive cryopreservation

The clinical application of human bone marrow derived multipotent mesenchymal stromal cells (MSC) requires expansion, cryopreservation, and transportation from the laboratory to the site of cell implantation. The cryopreservation and thawing process of MSCs may have important effects on the viability, growth characteristics and functionality of these cells both in vitro and in vivo. More importantly, MSCs after two rounds of cryopreservation have not been as well characterized as fresh MSCs from the transplantation perspective. The objective of this study was to determine if the effect of successive cryopreservation of pooled MSCs during the exponential growth phase could impair their morphology, phenotype, gene expression, and differentiation capabilities. MSCs cryopreserved at passage 3 (cell bank) were thawed and expanded up to passage 4 and cryopreserved for the second time. These cells (passive) were then thawed and cultured up to passage 6, and, at each passage MSCs were characterized. As control, pooled passage 3 cells (active) after one round of cryopreservation were taken all the way to passage 6 without cryopreservation. We determined the growth rate of MSCs for both culture conditions in terms of population doubling number (PDN) and population doubling time (PDT). Gene expression profiles for pluripotency markers and tissue specific markers corresponding to neuroectoderm, mesoderm and endoderm lineages were also analyzed for active and passive cultures of MSC. The results show that in both culture conditions, MSCs exhibited similar growth properties, phenotypes and gene expression patterns as well as similar differentiation potential to osteo‐, chondro‐, and adipo‐lineages in vitro. To conclude, it appears that successive or multiple rounds of cryopreservation of MSCs did not alter the fundamental characteristics of these cells and may be used for clinical therapy. J. Cell. Biochem. 113: 3153–3164, 2012. © 2012 Wiley Periodicals, Inc.     

Endometrial and endocervical secretion: the search for histochemical differentiation

OBJECTIVE: To determine the ideal histochemical stain to differentiate between non-neoplastic and neoplastic endocervix and endometrium. STUDY DESIGN: A total of 90 cases representing nonneoplastic cervix, non-neoplastic endometrium, endocervical adenocarcinoma and endometrial adenocarcinoma were stained with toluidine blue (TB); methylene blue (MB); mucicarmine (MUC); periodic acid-Schiff before and after diastase digestion (PAS, PAS-D); Alcian blue, pH 2.5 (AB); and periodic acid-Schiff after Alcian blue, pH 2.5 (PAB). Cases were blinded and randomly divided between two pathologists for evaluation of the staining and the staining distribution of the glandular epithelium by means of a 36-color scheme. RESULTS: The majority of non-neoplastic endocervix samples stained blue with MB (57%), fuchsia with MUC (70%), magenta with PAS (77%) and PAS-D (73%) and dark turquoise with AB (70%). The majority of non-neoplastic endometrium samples stained slate blue with TB (60%) and pink with PAS-D (53.3%). There is statistical difference (p < 0.05) in the color of the epithelium and secretions between the non-neoplastic cervix and endometrium. The malignant glands of endocervical origin could be differentiated significantly (p = 0.043) from non-neoplastic endocervical epithelium by MUC. The epithelium of the non-neoplastic endometrium is significantly differentiated from malignant endometrium using TB (p = 0.015) and MB (p = 0.038). Endocervical carcinoma could be significantly differentiated from endometrial carcinoma by MB. The staining in endocervical adenocarcinoma and endometrial carcinoma was predominantly present in both apical and cytoplasmic locations compared to their non-neoplastic counterparts (endocervix, p = 0.003; endometrium, p = 0.049). CONCLUSION: This study showed that a panel of histochemical stains could differentiate glandular cells of endocervical epithelium from endometrium.     

Ectodermal dysplasia-cutaneous syndactyly syndrome maps to chromosome 7p21.1-p14.3

Ectodermal dysplasia syndromes are genetically heterogeneous group of disorders involving one or more of the classical ectodermal appendages (hair, nail, teeth, sweat glands) in association with anomalies of other organs or systems. In the present study a novel form of ectodermal dysplasia syndrome, ectodermal dysplasia cutaneous syndactyly (EDCS), segregating in an autosomal recessive pattern in a Pakistani family was investigated. The clinical features of the affected individuals included large prominent ear pinnae, tooth enamel hypoplasia, hypoplastic nails, bilateral partial cutaneous syndactyly, hypotrichosis, palmoplantar keratoderma and hyperhidrosis. Through genetic linkage study, EDCS syndrome was mapped on human chromosome 7p21.1-p14.3 flanked by markers D7S488 and D7S817. A maximum two-point LOD score of 2.94 (θ = 0.00) was obtained at marker D7S2496 while a maximum multipoint LOD score of 3.07 was obtained with several markers along the disease-interval. This interval spans 19.80-cM, which corresponds to 13.74-Mbp according to the sequence-based physical map (Build 36.1). Sequence analysis of 27 candidate genes, located in the candidate interval, did not reveal any functional sequence variant.     

Rats’ learning of a new motor skill: Insight into the evolution of motor sequence learning

Recent behavioral and neural evidence has suggested that ethologically relevant sub-movements (movement primitives) are used by primates for more complex motor skill learning. These primitives include extending the hand, grasping an object, and holding food while moving it toward the mouth. In prior experiments with rats performing a reach-to-grasp-food task, we observed that especially during early task learning, rats appeared to have movement primitives similar to those seen in primates. Unlike primates, however, during task learning the rats performed these sub-movements in a disordered manner not seen in humans or macaques, e.g. with the rat chewing before placing the food pellet in its mouth. Here, in two experiments, we tested the hypothesis that for rats, learning this ecologically relevant skill involved learning to concatenate the sub-movements in the correct order. The results confirmed our initial observations, and suggested that several aspects of forepaw/hand use, taken for granted in primate studies, must be learned by rats to perform a logically connected and seemingly ecologically important series of sub-movements. We discuss our results from a comparative and evolutionary perspective.     

Identification of genetic loci involved in diabetes using a rat model of depression

While diabetic patients often present with comorbid depression, the underlying mechanisms linking diabetes and depression are unknown. The Wistar Kyoto (WKY) rat is a well-known animal model of depression and stress hyperreactivity. In addition, the WKY rat is glucose intolerant and likely harbors diabetes susceptibility alleles. We conducted a quantitative trait loci (QTL) analysis in the segregating F₂ population of a WKY × Fischer 344 (F344) intercross. We previously published QTL analyses for depressive behavior and hypothalamic-pituitary-adrenal (HPA) activity in this cross. In this study we report results from the QTL analysis for multiple metabolic phenotypes, including fasting glucose, post-restraint stress glucose, postprandial glucose and insulin, and body weight. We identified multiple QTLs for each trait and many of the QTLs overlap with those previously identified using inbred models of type 2 diabetes (T2D). Significant correlations were found between metabolic traits and HPA axis measures, as well as forced swim test behavior. Several metabolic loci overlap with loci previously identified for HPA activity and forced swim behavior in this F₂ intercross, suggesting that the genetic mechanisms underlying these traits may be similar. These results indicate that WKY rats harbor diabetes susceptibility alleles and suggest that this strain may be useful for dissecting the underlying genetic mechanisms linking diabetes, HPA activity, and depression.     

Adaptive Autoimmunity and Foxp3-Based Immunoregulation in Zebrafish

Background

Jawed vertebrates generate their immune-receptor repertoire by a recombinatorial mechanism that has the potential to produce harmful autoreactive lymphocytes. In mammals, peripheral tolerance to self-antigens is enforced by Foxp3⁺ regulatory T cells. Recombinatorial mechanisms also operate in teleosts, but active immunoregulation is thought to be a late incorporation to the vertebrate lineage.

Methods/Principal Findings

Here we report the characterization of adaptive autoimmunity and Foxp3-based immunoregulation in the zebrafish. We found that zebrafish immunization with an homogenate of zebrafish central nervous system (zCNS) triggered CNS inflammation and specific antibodies. We cloned the zebrafish ortholog for mammalian Foxp3 (zFoxp3) which induced a regulatory phenotype on mouse T cells and controlled IL-17 production in zebrafish embryos.

Conclusions/Significance

Our findings demonstrate the acquisition of active mechanisms of self-tolerance early in vertebrate evolution, suggesting that active regulatory mechanisms accompany the development of the molecular potential for adaptive autoimmunity. Moreover, they identify the zebrafish as a tool to study the molecular pathways controlling adaptive immunity.     

Co-expression of chimeric chitinase and a polygalacturonase-inhibiting protein in transgenic canola <Emphasis Type="Italic">(Brassica napus)</Emphasis> confers enhanced resistance to <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis>

Objectives

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum is one of the major fungal diseases of canola. To develop resistance against this fungal disease, the chit42 from Trichoderma atroviride with chitin-binding domain and polygalacturonase-inhibiting protein 2 (PG1P2) of Phaseolus vulgaris were co-expressed in canola via Agrobacterium-mediated transformation.

Results

Stable integration and expression of transgenes in T₀ and T₂ plants was confirmed by PCR, Southern blot and RT-PCR analyses. Chitinase activity and PGIP2 inhibition were detected by colorimetric and agarose diffusion assay in transgenic lines but not in untransformed plants. The crude proteins from single copy transformant leaves having high chitinase and PGIP2 activity (T16, T8 and T3), showed up to 44 % inhibition of S. sclerotiorum hyphal growth. The homozygous T₂ plants, showing inheritance in Mendelian fashion (3:1), were further evaluated under greenhouse conditions for resistance to S. sclerotiorum. Intact plants contaminated with mycelia showed resistance through delayed onset of the disease and restricted size and expansion of lesions as compared to wild type plants.

Conclusions

Combined expression of chimeric chit42 and pgip2 in Brassica napus L. provide subsequent protection against SSR disease and can be helpful in increasing the canola production in Iran.

     

Evaluating the role of autologous mesenchymal stem cell seeded on decellularized pericardium in the treatment of myocardial infarction: an animal study

Inappropriate left ventricular remodeling following myocardial infarction (MI) can result in subsequent severe dysfunction. In this study, we tested the hypothesis that decellularized pericardium (DP) or seeded pericardial patch with autologous adipose-derived mesenchymal stem cells (ADMSCs) could be safely used in a MI scar and could improve heart function. Twelve rabbits were randomly divided into three equal groups. Four weeks after MI induction by ligation of the left anterior descending artery in 12 rabbits, animals of G1 (n = 4) received DP patch with labeled ADMSCs. DP patch was implanted in animals of G2 (n = 4). Rabbits of G3 (n = 4) remained without any intervention after MI induction (control group). Serial examinations including echocardiography, electrocardiography (ECG), scanning electron microscopy, histology and immunohistochemistry (IHC) were performed to evaluate the efficacy of the implanted scaffolds on recovery of the infracted myocardium. The results demonstrated that left ventricular contractile function and myocardial pathological changes were significantly improved in rabbits implanted with either DP or ADMSC-seeded pericardium. However, the seeded pericardium was more effective in scar repairing 2 months after the operation, IHC staining with Desmin and CD34 and positive immunofluorescence staining verified the differentiation of ADMSCs to functional cardiomyocytes. This approach may involve the application of autologous ADMSCs seeded on pericardial patch in an attempt to regenerate a contractible myocardium in an animal model of MI.