Notes on Strobilanthes cuspidata with reinstatement of Endopogon versicolor (Acanthaceae)

Endopogon versicolor Wight, previously treated as a synonym of Strobilanthes cuspidata (Benth.) T. Anderson, is reinstated as a distinct species and a new name S. benthamii B. Mani, Sinj. Thomas, Britto, A.K. Pradeep, Y.F. Deng & E.S.S. Kumar is necessarily proposed here. It differs from S. cuspidata by the stem and leaf indumentum, bract/calyx length ratio, corolla shape, pollen morphology, etc. Detailed descriptions, illustrations, pollen morphology and comparison with similar species are provided

Differential expression of akirin gene in black tiger shrimp Penaeus monodon in response to immunostimulant administration and infections with Vibrio harveyi and white spot syndrome virus

The akirin gene, which is strictly localized in the nucleus, plays a critical role in regulating antimicrobial peptide transcription, and has parallel functions to NF-kappa B signaling pathway in both vertebrates and invertebrates. In shrimp, the akirin gene is expressed as innate immunity in response to microbial infection. In the present study, expression of akirin gene in Penaeus monodon with respect to Vibrio harveyi and white spot syndrome virus (WSSV) infections and immunostimulant (beta-glucan) administration were investigated by quantitative polymerase chain reaction. The gene was expressed in various tissue samples of healthy shrimp. Maximum level of expression was immediately after V. harveyi infection, suggesting that it may be an early response gene. Gene expression was remarkably upregulated in the lymphoid organ, gill, and hepatopancreas, whereas downregulation was observed in hemocytes compared with the control. In the case of WSSV-infected samples, the akirin gene was significantly downregulated in the lymphoid organ but there was no significant difference in expression pattern in hemocytes compared to the control. In gill tissue, maximum expression was observed after 2 hr of infection, the same in hepatopancreas. Experimental challenge of beta-glucan fed shrimp infected with V. harveyi and WSSV resulted in significant upregulation of akirin gene expression in lymphoid and gill tissue

Hypertrophic Stimulation Increases β-actin Dynamics in Adult Feline Cardiomyocytes

The myocardium responds to hemodynamic stress through cellular growth and organ hypertrophy. The impact of cytoskeletal elements on this process, however, is not fully understood. While α-actin in cardiomyocytes governs muscle contraction in combination with the myosin motor, the exact role of β-actin has not been established. We hypothesized that in adult cardiomyocytes, as in non-myocytes, β-actin can facilitate cytoskeletal rearrangement within cytoskeletal structures such as Z-discs. Using a feline right ventricular pressure overload (RVPO) model, we measured the level and distribution of β-actin in normal and pressure overloaded myocardium. Resulting data demonstrated enriched levels of β-actin and enhanced translocation to the Triton-insoluble cytoskeletal and membrane skeletal complexes. In addition, RVPO in vivo and in vitro hypertrophic stimulation with endothelin (ET) or insulin in isolated adult cardiomyocytes enhanced the content of polymerized fraction (F-actin) of β-actin. To determine the localization and dynamics of β-actin, we adenovirally expressed GFP-tagged β-actin in isolated adult cardiomyocytes. The ectopically expressed β-actin-GFP localized to the Z-discs, costameres, and cell termini. Fluorescence recovery after photobleaching (FRAP) measurements of β-actin dynamics revealed that β-actin at the Z-discs is constantly being exchanged with β-actin from cytoplasmic pools and that this exchange is faster upon hypertrophic stimulation with ET or insulin. In addition, in electrically stimulated isolated adult cardiomyocytes, while β-actin overexpression improved cardiomyocyte contractility, immunoneutralization of β-actin resulted in a reduced contractility suggesting that β-actin could be important for the contractile function of adult cardiomyocytes. These studies demonstrate the presence and dynamics of β-actin in the adult cardiomyocyte and reinforce its usefulness in measuring cardiac cytoskeletal rearrangement during hypertrophic stimulation

Inhibition of Histone Deacetylase Protects the Retina from Ischemic Injury

The present study was designed to assess the neuroprotective action of the nonselective HDAC inhibitor trichostatin A (TSA) in an adult rodent model of retinal ischemia

DACH1 negatively regulates the human RANK ligand gene expression in stromal/preosteoblast cells

Receptor activator of NF-kappaB ligand (RANKL) is a critical osteoclastogenic factor that is expressed on bone marrow stromal/preosteoblast cells. Most bone resorption stimuli induce osteoclast formation by modulating RANKL expression in these cells. However, little is known about the mechanisms regulating RANKL gene expression. We recently reported that heat shock factor-2 (HSF-2) is a downstream target for FGF-2 signaling to enhance RANKL gene transcription in marrow stromal/preosteoblast cells. In this study, we show that DACH1 (human homologue of Drosophila dachshund gene) negatively regulates RANKL gene expression and suppresses FGF-2-enhanced RANKL gene expression in these cells. DACH1 contains a conserved dachshund domain (DS) in the N-terminal region, which interacts with the nuclear co-repressor (NCoR) to repress gene expression. Co-expression of DACH1 with hRANKL promoter-luciferase reporter plasmid in normal human bone marrow-derived stromal cells significantly decreased (3.3-fold) FGF-2-stimulated hRANKL gene promoter activity. Deletion of DS domain abolished DACH1 inhibition of FGF-2-enhanced RANKL gene promoter activity. Western blot analysis confirmed that DACH1 suppressed FGF-2-stimulated RANKL expression in marrow stromal/preosteoblast cells. We show HSF-2 co-immune precipitated with DACH1 and that FGF-2 stimulation significantly increased (2.7-fold) HSF-2 binding to DACH1. Confocal microscopy analysis further demonstrated that FGF-2 promotes HSF-2 nuclear transport and co-localization with DACH1 in marrow stromal cells. Co-expression of NCoR with DACH1 significantly decreased (5.3-fold) and siRNA suppression of NCoR in DACH1 co-transfected cells increased (3.6-fold) RANKL promoter activity. Furthermore, DACH1 co-expression with NCoR significantly decreased (7.5-fold) RANKL mRNA expression in marrow stromal cells. Collectively, these studies indicate that NCoR participates in DACH1 repression of RANKL gene expression in marrow stromal/preosteoblast cells. Thus, DACH1 plays an important role in negative regulation of RANKL gene expression in marrow stromal/preosteoblast cells in the bone microenvironment

Perturbation of β-actin dynamics by dominant-negative Rac1 (N17 Rac) expression.

<p><b>A</b>) Adult feline cardiomyocytes were infected with both β-actin-GFP and Rac N17 adenoviruses for 36 h and then stimulated with 100 nM ET for 48 h. Cells were then imaged using confocal microscopy. Scale  = 5 µm.</p

β-actin dynamics as measured by fluorescence recovery after photobleaching in adult cardiomyocytes expressing β-actin-GFP.

<p>Cells (n = 10) were treated with endothelin (200 nM) or insulin (100 nM) for 30 min and subjected to FRAP study. From the recovery of fluorescence the t½ was calculated as described under <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0011470#s2" target="_blank">Materials and Methods</a>.</p

β-actin is enriched and localized to cardiac cytoskeleton during pressure overload induced hypertrophy.

<p><b>A</b>) Normally loaded LV and pressure overloaded RV tissues from adult felines that underwent right ventricular pressure overload hypertrophy (RVPO) for 48 h were extracted into Triton-soluble, Triton-insoluble low-spin cytoskeletal (CSK) and Triton-insoluble high-spin membrane skeletal (MSK) fractions. The tissue fractions were separated by SDS-PAGE and Western blotted with indicated antibodies. <b>B</b>) LV and RV tissues from feline RVPO myocardium were fractionated into F- and G-actin as described under <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0011470#s2" target="_blank">Materials and Methods</a>. The pellet (corresponding to F-actin) and the Supernatant (Sup; corresponding to G-actin) were analyzed by Western blot using indicated antibodies. <b>C</b>) LV and RV tissue samples were cryosectioned into 12 µm slices and immunostained with β-actin (green) and α−actinin (red) antibodies and analyzed using a confocal microscope. Scale bar  = 5 µm.</p

Table showing β-actin dynamics changes upon dominant negative Rac1 expression.

<p>FRAP experiments were performed in adult cardiomyocytes co-expressing the β-actin-GFP and N17 Rac following their treatment with +/− 100 nM ET. Analyses were made in at least 10 independent cells for statistical evaluation. Values are expressed as Mean ± S.D. *p<0.05 when compared to control. ^#p<0.05 when compared to ET-1 treated cells.</p