Dark-induced hormone changes coincide with the resumption of light-inhibited shoot growth in Catasetum fimbriatum (Orchidaceae)

Catasetum fimbriatum plants cultivated in the absence of light exhibit continuous shoot growth leading to the formation of nodes and internodes. On the other hand, when these plants are incubated in the presence of light, shoot longitudinal growth is inhibited and pseudobulbs develop just below the shoot apical meristem. These facts provide evidence of a possible influence of light on mitotic cell division in the shoot apex as well as on pseudobulb initiation. The effects of light and dark on the interruption and/or maintenance of shoot apex mitotic activity and the subsequent formation of pseudobulbs in the sub-meristematic regions were investigated by means of histological and hormonal studies. The interruption of shoot apex development occurred around the 150th d of light incubation and seems to have resulted from the establishment of a strong storage sink in the region of the future pseudobulb, in detriment to the continuous activity of the shoot apical meristem. The reduced total cytokinins/IAA ratio in the apex, mainly due to high levels of IAA, could be a key factor in the interruption of cell divisions. Transfer to the dark brings about the resumption of shoot apex development of plants through the re-entrance of cells in the cell cycle which coincides with a significant increase in the total cytokinins/IAA ratio. (C) 2009 Elsevier GmbH. All rights reserved.

Nitrosyl ethylenediaminetetraacetate ruthenium(II) complex promotes cellular growth and could be used as nitric oxide donor in plants

Over recent years nitric oxide (NO) not only has appeared as an important endogenous signaling molecule in plants and as a mediator in many developmental and physiological processes, but has also received recognition as a plant hormone. The impressive recent achievements in elucidating the role of NO in plants have come about by the application of NO donors. The aim herein was to study the effects of the different NO donors, sodium nitroprusside (SNP) and the nitrosyl ethylenediaminetetraacetate ruthenium(II) ([Ru(NO)(Hedta)]) complex on cellular growth in embryogenic suspension cultures of Araucaria angustifolia. Appraisal of our data revealed that [Ru(NO)(Hedta)] stimulated about 60% of cellular growth in embryogenic suspension cultures of A. angustifolia, with results similar to those observed with the SNP donor. Nevertheless, application of the NO scavenger PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) inhibited this cellular growth in both. Cellular growth was correlated with an increase in endogenous NO levels after 21 days of culture, especially in treatments with NO donors. Our results demonstrated that the [Ru(NO)Hedta] complex could possibly be used as a NO donor in plants. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

An endogenous regulator of inflammation, resolvin E1, modulates osteoclast differentiation and bone resorption

Background and purpose: The inflammation-resolving lipid mediator resolvin E1 (RvE1) effectively stops inflammation-induced bone loss in vivo in experimental periodontitis. It was of interest to determine whether RvE1 has direct actions on osteoclast (OC) development and bone resorption. Experimental approach: Primary OC cultures derived from mouse bone marrow were treated with RvE1 and analysed for OC differentiation, cell survival and bone substrate resorption. Receptor binding was measured using radiolabelled RvE1. Nuclear factor (NF)-kappa B activation and Akt phosphorylation were determined with western blotting. Lipid mediator production was assessed with liquid chromatography tandem mass spectrometry. Key results: OC growth and resorption pit formation were markedly decreased in the presence of RvE1. OC differentiation was inhibited by RvE1 as demonstrated by decreased number of multinuclear OC, a delay in the time course of OC development and attenuation of receptor activator of NF-kappa B ligand-induced nuclear translocation of the p50 subunit of NF-kappa B. OC survival and apoptosis were not altered by RvE1. Messenger RNA for both receptors of RvE1, ChemR23 and BLT(1) is expressed in OC cultures. Leukotriene B(4) (LTB(4)) competed with [(3)H] RvE1 binding on OC cell membrane preparations, and the LTB(4) antagonist U75302 prevented RvE1 inhibition of OC growth, indicating that BLT(1) mediates RvE1 actions on OC. Primary OC synthesized the RvE1 precursor 18R-hydroxy-eicosapentaenoic acid and LTB(4). Co-incubation of OC with peripheral blood neutrophils resulted in transcellular RvE1 biosynthesis. Conclusions and implications: These results indicate that RvE1 inhibits OC growth and bone resorption by interfering with OC differentiation. The bone-sparing actions of RvE1 are in addition to inflammation resolution, a direct action in bone remodelling.

Privatization and economic growth in Australia: the shorthand of a long process

The impact of privatization on economic growth has been little investigated relative to disaggregated approaches. A growth accounting framework is used here to investigate the impact of privatization on growth for the  Australian economy. The contribution of public capital to the private sector and whether the growth process is endogenous or Solow is evaluated. Separate measures of public and private capital are computed in order to estimate their impacts with labour on Australian gross domestic product (GDP) growth for the period 1960 to 2003. A simple growth rates version is found preferred by stationarity and other tests. Labour growth appears to strongly positively influence the growth of GDP. In contrast, public capital growth has no statistically significant effect on GDP growth, or on private capital productivity. The data are consistent with the hypothesis that the coefficients of the growth equation are the same before and during privatization.

Modelling the relationship between defense spending and economic growth for the Fiji Islands

The goal of this paper is to examine the nexus between GDP and military expenditure. We model this relationship within a multivariate framework by including exports in the model. We use the recently developed bounds testing approach to cointegration and find that there is a long run relationship among the variables when GDP is the endogenous variable. Normalizing on GDP and using four different estimators, we find that in the long run both military expenditure and exports have a positive impact on GDP. Finally, using the Granger causality test, we find that there is evidence for military expenditure Granger causing exports and exports Granger causing GDP, implying that military expenditure indirectly Granger causes GDP in the short run. In the long run, we find that both military expenditure and exports Granger cause GDP for Fiji. Our findings are consistent with the Keynesian school of thought, leading us to derive some policy implications.

Effects of survivin antagonists of growth of established tumors and B7-1 immunogene therapy

Background: Survivin, a member of the inhibitor of apoptosis (IAP) protein family, is detectable in most types of cancer, and its presence is associated with a poor prognosis. We determined the effects of gene-based therapies that inhibit survivin function in a mouse tumor model. Methods: Using five to six mice per treatment group, we injected tumors derived from mouse EL-4 thymic lymphoma cells with plasmids encoding antisense survivin, a dominant-negative mutant survivin, and the T-cell costimulator B7-1. Expression of endogenous survivin and the proteins encoded by the injected plasmids were examined by immunohistochemical staining of tumor sections and by western blot and flow cytometry analyses of isolated tumor cells. Tumor growth, the generation of antitumor cytotoxic T-lymphocyte (CTL) activity, apoptosis, and the contribution of leukocyte subsets to antitumor activity were measured. All statistical tests were two-sided. Results: Large (1.0-cm diameter) tumors had approximately 10-fold more survivin than small (0.2-cm diameter) tumors. At 28 days after injection, antisense and dominant-negative mutant survivin plasmids statistically significantly inhibited the growth of both small (P = .006 and P = .0018, respectively) and large (P<.001 for both plasmids) EL-4 tumors compared with tumors injected with empty plasmid. The growth of large tumors was further inhibited by intratumoral injection with antisense survivin and B7-1 (P = .004); thus, inhibition of survivin expression renders large tumors susceptible to B7-1-mediated immunotherapy. Mice whose tumors were completely eradicated by injection of B7-1 remained tumor free for 26 days after re-injection with EL-4 cells (when the experiment ended). Compared with tumors injected with empty plasmid, tumors injected with survivin-based plasmids had increased apoptosis, and animals bearing such tumors generated more antitumor CTLs. Conclusion: Intratumoral injection of plasmids that block survivin expression and stimulate the generation of tumor-specific CTLs may be beneficial for the treatment of large lymphomas.

Dynamics of endogenous food production in Cherax destructor Clark culture ponds

This study examined endogenous food production in crayfish culture ponds and the pond dynamics resulting from the interactions of pond bottom and water column parameters under a crop flooding strategy.

An essay on economic growth: classical determinants, convergence and financial development

This dissertation surveys the literature on economic growth. I review a substantial number of articles published by some of the most renowned researchers engaged in the study of economic growth. The literature is so vast that before undertaking new studies it is very important to know what has been done in the field. The dissertation has six chapters. In Chapter 1, I introduce the reader to the topic of economic growth. In Chapter 2, I present the Solow model and other contributions to the exogenous growth theory proposed in the literature. I also briefly discuss the endogenous approach to growth. In Chapter 3, I summarize the variety of econometric problems that affect the cross-country regressions. The factors that contribute to economic growth are highlighted and the validity of the empirical results is discussed. In Chapter 4, the existence of convergence, whether conditional or not, is analyzed. The literature using both cross-sectional and panel data is reviewed. An analysis on the topic of convergence using a quantile-regression framework is also provided. In Chapter 5, the controversial relationship between financial development and economic growth is analyzed. Particularly, I discuss the arguments in favour and against the Schumpeterian view that considers financial development as an important determinant of innovation and economic growth. Chapter 6 concludes the dissertation. Summing up, the literature appears to be not fully conclusive about the main determinants of economic growth, the existence of convergence and the impact of finance on growth.

Macromineral requirements for the maintenance and growth of Boer crossbred kids

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The importance of endogenous nutrition of chicks from divergent strains for growing tested by deutectomy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Endogenous and exogenous polyamines in the organogenesis in Curcuma longa L.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Endogenous annexin A1 counter-regulates bleomycin-induced lung fibrosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Endophytic and rhizospheric enterobacteria isolated from sugar cane have different potentials for producing plant growth-promoting substances

Background and aims Endophytic and rhizospheric environments differ in many respects, leading to the presence of different bacterial communities at each site. However, microorganisms such as enterobacteria can be found both within plants and in the surrounding soil. Bacteria must present differences in the traits that affect such environments in order to successfully colonise them. The present study compared the plant growth-promoting potential of diazotrophic enterobacteria isolated from the rhizosphere and from within surface-disinfected plants. Methods A total of 46 diazotrophic enterobacterial strains (21 rhizospheric and 25 putatively endophytic) belonging to the Klebsiella and Enterobacter genera, which are prevalent in sugar cane plantations, were isolated from the rhizosphere and from surface-disinfected plants. Their ability to synthesise amino acids using combined nitrogen obtained from nitrogen fixation, and their ability to synthesise indole-3-acetic acid (IAA) were determined by high performance liquid chromatography. Endogenous ethylene production by the bacteria was measured using gas chromatography, and biocontrol of phytopathogenic fungi was determined qualitatively using a dual culture technique. Results The putative endophytes released significantly higher amounts of amino acids than the rhizospheric bacteria, whilst the latter produced higher quantities of ethylene and were more actively antagonistic to fungi. Both types of bacteria released similar amounts of IAA. Conclusion Endophytic and rhizospheric bacteria differ in their capacity to release plant growth-promoting substances, which may be a reflection of their adaptations and an indication of their potential impact on their natural environment.

Expression profiling in developing peach seed and mesocarp as affected by growth regulators

Jasmonates (JAs) and spermidine (Sd) influence fruit (and seed) development and ripening. In order to unravel their effects in peach fruit, at molecular level, field applications of methyl jasmonate (MJ) and propyl dihydrojasmonate (PDJ), and Sd were performed at an early developmental stage (late S1). At commercial harvest, JA-treated fruit were less ripe than controls. Realtime RT-PCR analyses confirmed a down-regulation of ethylene biosynthetic, perception and signaling genes, and flesh softening-related genes. The expression of cell wall-related genes, of a sugar-transporter and hormone-related transcript levels was also affected by JAs. Seeds from JA-treated fruit showed a shift in the expression of developmental marker genes suggesting that the developmental program was probably slowed down, in agreement with the contention that JAs divert resources from growth to defense. JAs also affected phenolic content and biosynthetic gene expression in the mesocarp. Levels of hydroxycinnamic acids, as well as those of flavan-3-ols, were enhanced, mainly by MJ, in S2. Transcript levels of phenylpropanoid pathway genes were up-regulated by MJ, in agreement with phenolic content. Sd-treated fruits at harvest showed reduced ethylene production and flesh softening. Sd induced a short-term and long-term response patterns in endogenous polyamines. At ripening the up-regulation of the ethylene biosynthetic genes was dramatically counteracted by Sd, leading to a down-regulation of softening-related genes. Hormone-related gene expression was also altered both in the short- and long-term. Gene expression analyses suggest that Sd interfered with fruit development/ripening by interacting with multiple hormonal pathways and that fruit developmental marker gene expression was shifted ahead in accord with a developmental slowing down. 24-Epibrassinolide was applied to Flaminia peaches under field conditions early (S1) or later (S3) during development. Preliminary results showed that, at harvest, treated fruit tended to be larger and less mature though quality parameters did not change relative to controls.

Growth hormone (GH)-releasing hormone increases the expression of the dominant-negative GH isoform in cases of isolated GH deficiency due to GH splice-site mutations

An autosomal dominant form of isolated GH deficiency (IGHD II) can result from heterozygous splice site mutations that weaken recognition of exon 3 leading to aberrant splicing of GH-1 transcripts and production of a dominant-negative 17.5-kDa GH isoform. Previous studies suggested that the extent of missplicing varies with different mutations and the level of GH expression and/or secretion. To study this, wt-hGH and/or different hGH-splice site mutants (GH-IVS+2, GH-IVS+6, GH-ISE+28) were transfected in rat pituitary cells expressing human GHRH receptor (GC-GHRHR). Upon GHRH stimulation, GC-GHRHR cells coexpressing wt-hGH and each of the mutants displayed reduced hGH secretion and intracellular GH content when compared with cells expressing only wt-hGH, confirming the dominant-negative effect of 17.5-kDa isoform on the secretion of 22-kDa GH. Furthermore, increased amount of 17.5-kDa isoform produced after GHRH stimulation in cells expressing GH-splice site mutants reduced production of endogenous rat GH, which was not observed after GHRH-induced increase in wt-hGH. In conclusion, our results support the hypothesis that after GHRH stimulation, the severity of IGHD II depends on the position of splice site mutation leading to the production of increasing amounts of 17.5-kDa protein, which reduces the storage and secretion of wt-GH in the most severely affected cases. Due to the absence of GH and IGF-I-negative feedback in IGHD II, a chronic up-regulation of GHRH would lead to an increased stimulatory drive to somatotrophs to produce more 17.5-kDa GH from the severest mutant alleles, thereby accelerating autodestruction of somatotrophs in a vicious cycle.