Floral organogenesis of Chloranthus sessilifolius, with special emphasis on the morphological nature of the androecium of Chloranthus (Chloranthaceae)

 Floral organogenesis of Chloranthus sessilifolius K. F. Wu is described. The inflorescence primordium is dome-like in the beginning and then elongates, and bract primordia initiate almost decussately. Each floral primordium, arising from the axil of a bract, soon becomes a scale-like structure, with three primordia of androecial lobes originating from its abaxial part, and the gynoecial primordium in adaxial position. As the androecial lobes become more distinct, four thecae are already in differentiation, and the gynoecial primordium appears as a shallow disc. The androecial lobes do not extend their length until the thecae approach maturity and the stigma is differentiated. The androecial lobes are united at all the stages of development, and the entire androecium falls off as a unit at the end of anthesis. Based on these results, combined with published evidence from neobotany, palaeobotany and phylogenetic studies, the morphological nature of the androecium of Chloranthus is further discussed. Our studies support the viewpoint that the androecial structure of Chloranthus may have arisen by splitting of a single stamen with 2 marginal thecae. Received May 2, 2001 Accepted December 18, 2001     

Local anaesthetic lidocaine modulates epiphyllous bud differentiation in Kalanchoe pinnata

A single treatment with lidocaine(2-Diethylamino-N-[2,6-dimethylphenyl]-acetamide) – a potent localanaesthetic(LA), caused significant and extensive inhibition of epiphyllous buddifferentiation in Kalanchoe pinnata, in a long –term irreversible manner. These effects were both concentration and treatmentduration dependent, with either variant generating similar and additiveeffects.The growth responses studied had differential sensitivity towards the applieddosage of the anaesthetic. Lidocaine also appears to influence expression oftheorganogenic potential of buds since for all inhibitory doses a significantpercentage produced shoots but not roots.     

Brain-derived neurotrophic factor (BDNF) mediates bone morphogenetic protein-2 (BMP-2) effects on cultured striatal neurones

Bone morphogenetic proteins are members of the transforming growth factor-beta superfamily that have multiple functions in the developing nervous system. One of them, bone morphogenetic protein-2 (BMP-2), promotes the differentiation of cultured striatal neurones, enhancing dendrite growth and calbindin-positive phenotype. Bone morphogenetic proteins have been implicated in cooperative interactions with other neurotrophic factors. Here we examined whether the effects of BMP-2 on cultured striatal neurones are mediated or enhanced by other neurotrophic factors. BMP-2 had a cooperative effect with low doses of brain-derived neurotrophic factor or neurotrophin-3 (but not with other neurotrophic factors such as glial cell line-derived neurotrophic factor, neurturin or transforming growth factor-beta 2) on the number of calbindin-positive striatal neurones. Moreover, BMP-2 induced phosphorylated Trk immunoreactivity in cultured striatal neurones, suggesting that neurotrophins are involved in BMP-2 neurotrophic effects. The addition of TrkB-IgG or antibodies against brain-derived neurotrophic factor abolished the effects of BMP-2 on the number and degree of differentiation of calbindin-positive striatal neurones. Indeed, BMP-2 treatment increased brain-derived neurotrophic factor protein levels in treated cultures media and BDNF immunocytochemistry revealed that this neurotrophin was produced by neuronal cells. Taken together, these results indicate that brain-derived neurotrophic factor mediates the effects of BMP-2 on striatal neurones.     

In vitro culture of human chondrocytes (1): A novel enhancement action of ferrous sulfate on the differentiation of human chondrocytes

Chondrogenic differentiation of mesenchymal cells is generally thought to be initiated by the inductive action of specific growth factors and depends on intimate cell-cell interactions. The aim of our investigation was to characterize the influences of basic fibroblast growth factor (bFGF) and ferroussulfate (FeSO₄) on proliferation and differentiation of human articular chondrocytes (HAC). This is the first report of the effects of FeSO₄ on chondrogenesis of HAC. Multiplied chondrocytes of hip and shoulder joints were cultured in chondrocyte growth medium supplemented with bFGF, FeSO₄, or both bFGF + FeSO₄ for4weeks. A 20 μl aliquot of a cell suspension containing2 × 10⁷ cells ml⁻¹ was delivered onto each well of 24-well tissue culture plates. Cells cultured with the growth medium only was used as a control. Alamar blue and alcian blue staining were done to determine the chondrocyte proliferation and differentiation, respectively, after 4 weeks. The samples exposed to bFGF, FeSO₄, and combination of both indicated sufficient cell proliferation similar to the control level. Differentiations of the HAC exposed to bFGF, FeSO₄,and bFGF + FeSO₄ were 1.2-, 2.0-, and 2.2-fold of the control, respectively. Therefore, chondrocyte differentiation was significantly enhanced by the addition of FeSO₄ andbFGF + FeSO₄. The combined effects of bFGF and FeSO₄ were additive, rather than synergistic. These results suggest that treatment with ferrous sulfate alone or in combination with basic fibroblast growth factor etc, is a powerful tool to promote the differentiation of HAC for the clinical application. This revised version was published online in August 2006 with corrections to the Cover Date.     

Oxypetalum banksii subsp. banksii: a taxon of Asclepiadaceae with an extragynoecial compitum

 The floral morphology of seven Oxypetalum species and, in particular, the spatial relationship between the five stigmatic chambers and two separate ovaries of their flowers with respect to transmission of the pollen tube are studied. In all species, except O. banksii subsp. banksii, floral morphology is similar to that in other Asclepiadeae, and the flowers pollinated with one pollinium develop only one follicle, which means compitum absence. In O. banksii subsp. banksii flowers, the secretory interstaminal tissue lines the inner walls of the stigmatic chambers as in the other species studied, but it also reaches the upper part of the inner surface of the filament tube, where it surrounds the styles, an unprecedented feature for Asclepiadaceae. This tissue secretes nectar and mucilage; the latter acts as transmitting medium for the growth of pollen tubes from pollinia inserted and hydrated in stigmatic chambers (“hyperstigmas”). Mucilage also functions as an extragynoecial compitum: in flowers pollinated with one pollinium both carpels develop into a follicle. Received August 28, 2001; accepted April 9, 2002 Published online: October 14, 2002 Addresses of the authors: Milene Faria Vieira (e-mail: mfvieira@mail.ufv.br), Departamento de Biologia Vegetal, Universidade Federal de Vi?osa, 36571-000, Vi?osa, Minas Gerais, Brazil. George John Shepherd, Departamento de Botanica, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, 13083-970, Campinas, S?o Paulo, Brazil.     

Profiling the changes in signaling pathways in ascorbic acid/β‐glycerophosphate‐induced osteoblastic differentiation

Despite numerous reports on the ability of ascorbic acid and β‐glycerophosphate (AA/β‐GP) to induce osteoblast differentiation, little is known about the molecular mechanisms involved in this phenomenon. In this work, we used a peptide array containing specific consensus sequences (potential substrates) for protein kinases and traditional biochemical techniques to examine the signaling pathways modulated during AA/β‐GP‐induced osteoblast differentiation. The kinomic profile obtained after 7 days of treatment with AA/β‐GP identified 18 kinase substrates with significantly enhanced or reduced phosphorylation. Peptide substrates for Akt, PI3K, PKC, BCR, ABL, PRKG1, PAK1, PAK2, ERK1, ERBB2, and SYK showed a considerable reduction in phosphorylation, whereas enhanced phosphorylation was observed in substrates for CHKB, CHKA, PKA, FAK, ATM, PKA, and VEGFR‐1. These findings confirm the potential usefulness of peptide microarrays for identifying kinases known to be involved in bone development in vivo and in vitro and show that this technique can be used to investigate kinases whose function in osteoblastic differentiation is poorly understood. J. Cell. Biochem. 112: 71–77, 2011. © 2010 Wiley‐Liss, Inc.     

Flow cytometric analysis of porcine preadipocytes.

In this report, conditions have been established for utilizing monoclonal antibodies and fluorescence activated flow cytometry in studying antigen expression by primary porcine stromal-vascular cells cultured under various conditions. Single cells were isolated from cultures maintained in DME/F12 medium containing 10% fetal bovine serum, 2% pig serum, and containing 2% pig serum and 10 nM dexamethasone supplemented with growth hormone (GH), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta (TGF-beta). Flow cytometric analyses revealed that the proportion of cells expressing detectable levels of the AD-1 cells surface antigen was greater in cultures supplemented with 2% pig serum and 10 nM dexamethasone than in other media. In cultures, GH, TNF-alpha and TGF-beta each inhibited lipid deposition, whereas TNF-alpha and TGF-beta, but not GH, inhibited AD-1 antigen expression. Inhibition of lipid deposition as well as antigen expression by TNF-alpha and TGF-beta was reversible, but inhibition of cluster formation by GH was not reversed upon removal from cultures. In summary, differential effects of factors on surface antigen expression by preadipocytes are detectable by flow cytometry. Flow cytometric analysis using monoclonal antibodies produced against key developmentally regulated cell surface antigens is potentially a powerful analytical approach to the study of adipocyte development.