Search

The effectiveness of a double phase (solid/liquid) culture system (DPS) in comparison to a conventional (solid) system (CS) as well as, the role of various concentrations of activated charcoal in both systems on the enhancement of micropropagation of Malus sylvestris (L.) Mill. were investigated. In this study, lateral shoots were used as primary explants and a comparison for shoots regeneration and rooting abilities was assessed between DPS and CS micropropagation systems. Also, the effect of activated charcoal concentration (0, 250, 500, 1000 mg l-1) during rooting stage was evaluated for both micropropagation systems. All assessed biometric parameters were higher in the DPS propagation system. The addition of activated charcoal induced effectively rhizogenesis in both systems, whereas the highest value of roots length (13.16 cm) was in the DPS system supplemented with activated charcoal at 500 mg l-1. The DPS culture system represents a promising lowcost and timesaving technique which may improve micropropagation efficiency in producing a large quantity of homogenous wild apple plants. [ABSTRACT FROM AUTHOR]

Artichoke is of great economic significance in the Mediterranean basin. Although Italy has the richest primary cultivated gene pool, only a limited number of varietal types are vegetatively propagated to fit market demand. This could lead to the erosion of genetic resources. The development of cryopreservation procedures for the ex situ conservation of the genetic resources of artichoke is advisable not only to counter genetic erosion, but also to develop a certified phytosanitary germplasm collection. In this study, several parameters were tested in order to set up a simple and efficient procedure for the cryopreservation of artichoke shoot tips, based on vitrification/one-step cooling, which was successfully applied to two spring cultivars 'Grato 1' and 'Campagnano'. Cold acclimation prior to cooling was essential for tissue recovery and regrowth. The size of the shoot tips was also critical, and medium size tips (3-4 mm in length) proved to be the best responding starting material. The best survival percentage of cryopreserved shoot tips was 61% for 'Grato1' and 55% for 'Campagnano'. Cryopreserved shoot tips developed directly into plantlets, which proved to be stable in terms of chromosome numbers. The cryopreservation procedure was notably effective in eliminating the endemic Artichoke Latent virus ( ArLV) from both cultivars, irrespective of the shoot tip size used, which were up to 10 times the size used in meristem cultures for virus elimination. All plantlets analyzed for ArLV by RT-PCR were virus-free eight months after regeneration. An analysis of ArLV elimination and chromosome numbers of cryopreserved artichoke plants is presented here for the first time. [ABSTRACT FROM AUTHOR]

This study was carried out on Kober 5BB ( Vitis Berlandieri × V. riparia) grape rootstock shoot tips during the preparatory steps preceding the direct immersion in liquid nitrogen, in order to overcome until now unsuccessful cryopreservation with this species. The exposure of shoot tips to 0.3-0.4 M sucrose leads to a high cell solute concentration. The treatment with plant vitrification solution (PVS2) alone, i.e., not followed by storage in liquid nitrogen, markedly affected shoot tip survival. After a 30 min exposure, regrowth percentage of shoot tips decreased from 94 % (control) to 57 %, and dropped to 15 % when the treatment was prolonged up to 60 min. After a 90 min exposure, no regrowth occurred. In addition, plantlets regenerated from shoot tips which underwent 60 min or more exposure to PVS2 showed signs of malformation. Microscope observations of shoot tips treated with 0.3 or 0.4 M sucrose and 30 min PVS2 showed the presence of cells starting to plasmolyze, localized in the area surrounding the apical meristem. A limited presence of starch grains in meristem and bract cells was also noted. However, the most conspicuous consequence of prolonged PVS2 treatment was convex plasmolysis. The phenomenon was dependent on the time of PVS2 exposure. Indeed, after a 30 min treatment, plasmolysis was minimal or absent, but it increased with longer exposure to PVS2 at 4 °C. [ABSTRACT FROM AUTHOR]

In this study, the genes of theAux/IAA family were used as functional markers to characterise bud break stages in a white poplar clone. In the first experiment, under greenhouse conditions, the sprouting of repressed sylleptic buds was obtained by pruning the shoot tip during growing season. Buds were collected at 0, 6, 24 and 48 h after pruning for molecular analyses. A decrease in transcript level ofIAA4 andIAA8 genes was observed in the first and second bud below the cut after 6 and 24 h, respectively. In the second experiment, bud break of post-dormant proleptic buds was induced by forcing in climatic chamber. The first 6 and the following 6 buds below the apical one were sampled every 48 h during forcing. Anatomical studies were also carried out on buds and plants were equipped with stem and bud radial growth sensors to check their swelling. In both experiments, gene expression patterns showed a decrease and a successive increase in expression ofIAA4 andIAA8 genes during bud break. The transient down-regulation of these genes was observed only in buds that formed new branches. Thus, similar molecular mechanisms are involved in bud break of both sylleptic and proleptic buds. [ABSTRACT FROM AUTHOR]

A morphological and anatomical study of regenerants obtained from mandarin anther culture was carried out. Beside morphologically normal somatic embryos, abnormal structures were originated in the course of somatic embryogenesis. Anatomical anomalies can be found at several growth stages, causing the formation of slender stems, stubby structures, non-functional leaves. When too long, some structures are subject to shedding, with the formation of various abscission zones. Most of them are subject to degeneration, although many are capable of further, localized, morphogenesis. A thorough knowledge of morphology and anatomy of normal and abnormal regenerants could make possible to select and subculture the lines considered most suitable for conversion into plantlets. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Obesity is a potent risk factor in knee osteoarthritis (OA). It has been suggested that adipokines, secreted by adipose tissue (AT) and largely found in the synovial fluid of OA patients, derive in part from the infrapatellar fat pad (IFP), also known as Hoffa's fat pad. The goal of this study was to characterize IFP tissue in obese OA patients and to compare its features with thigh subcutaneous AT to determine whether the IFP contributes to local inflammation in knee OA via production of specific cytokines. METHODS: IFP and subcutaneous AT samples were obtained from 11 obese women (body mass index >/=30 kg/m(2)) with knee femorotibial OA. Gene expression was measured by real-time quantitative polymerase chain reaction. Cytokine concentrations in plasma and in conditioned media of cultured AT explants were determined by enzyme-linked immunosorbent assay or by Luminex xMAP technology. RESULTS: In IFP tissue versus subcutaneous AT, there was a decrease in the expression of genes for key enzymes implicated in adipocyte lipid metabolism, whereas the expression levels of genes for AT markers remained similar. A 2-fold increase in the expression of the gene for interleukin-6 (IL-6), a 2-fold increase in the release of IL-6, and a 3.6-fold increase in the release of soluble IL-6 receptor (sIL-6R) were observed in IFP samples, compared with subcutaneous AT, but the rates of secretion of other cytokines in IFP samples were similar to the rates in subcutaneous AT. In addition, leptin secretion was decreased by 40%, whereas adiponectin secretion was increased by 70%, in IFP samples versus subcutaneous AT. CONCLUSION: Our results indicate that the IFP cytokine profile typically found in OA patients could play a role in paracrine inflammation via the local production of IL-6/sIL-6R and that such a profile might contribute to damage in adjacent cartilage. [ABSTRACT FROM AUTHOR]

Regulation of glyceroneogenesis and its key enzyme cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) plays a major role in the control of fatty acid release from adipose tissue. Here we investigate the effect of rosiglitazone on the expression of genes involved in fatty acid metabolism and the resulting metabolic consequences. Rosiglitazone was administered to Zucker fa/ fa rats for 4 days and to 24 diabetic patients for 12 weeks, then mRNA expression for the genes encoding PEPCK-C, mitochondrial PEPCK, adipocyte lipid-binding protein, glycerol kinase, lipoprotein lipase and glycerol-3-phosphate dehydrogenase was examined in s.c. adipose tissue by real-time RT-PCR. Glyceroneogenesis was determined using [1−14C]pyruvate incorporation into lipids. Cultured adipose tissue explants from overweight women undergoing plastic surgery were incubated with rosiglitazone for various times before mRNA determination and analysis of PEPCK-C protein, activity and glyceroneogenesis. Rosiglitazone administration to rats induced the expression of the gene encoding PEPCK-C mRNA ( PCK1) and PEPCK-C activity in adipose tissue with a resulting 2.5-fold increase in glyceroneogenesis. This was accompanied by an improvement in dyslipidaemia as demonstrated by the decrease in plasma NEFAs and triacylglycerol. In rosiglitazone-treated diabetic patients, PCK1 mRNA was raised 2.5-fold in s.c. adipose tissue. Rosiglitazone treatment of adipose tissue explants from overweight women caused a selective augmentation in PCK1 mRNA which reached a maximum of 9-fold at 14 h, while mRNA for other genes remained unaffected. Experiments with inhibitors showed a direct and transcription-only effect, which was followed by an increase in PEPCK-C protein, enzyme activity and glyceroneogenesis. These results favour adipocyte glyceroneogenesis as the initial thiazolidinedione-responsive pathway leading to improvement in dyslipidaemia. [ABSTRACT FROM AUTHOR]

Numerical transfer-matrix approach and exact diagonalization technique exploiting the point-group symmetry and the properties of the shift operator are worked out in the framework of quantum statistical mechanics for the isotropic Heisenberg spin Hamiltonian with the ring geometry. They are applied in large-scale simulations to the title high nuclearity cyclic clusters Mn6 ( i.e. [Mn(hfac)2NITPh]6) and Ni12 ( i.e. Ni12(O2CMe)12(chp)12(H2O)6(THF)6) in order to model quantitatively their magnetic properties. For Ni12 complex new experimental susceptibility data are also reported. New microscopic spin model parameters for both molecules are obtained from a fit of the theoretical susceptibility curves to the experimental results. [ABSTRACT FROM AUTHOR]

The pyruvate dehydrogenase complex (PDHc) is a multienzyme complex consisting of three catalytic and two regulatory enzymes, as well as a less well defined subunit called protein X. PDHc deficiency is a common cause of congenital lactic acidosis. Most patients with PDH deficiency have a mutation in the α chain of the PDH E1 enzyme. Very few patients have been described in whom the basic defect of a PDH deficiency is situated in the X protein. We studied a boy with severe lactic acidosis and developmental delay in whom a deficiency of PDH activity led to further investigations. Immunochemical analysis with anti-PDHc antibodies demonstrated an absence of the X component. This report is the fourth family in which an abnormal protein X has been found. In cases with PDH deficiency where no mutation of the PDHE1α gene is found, further investigations by means of immunoblotting with specific antibodies against the different subunits should be performed. [ABSTRACT FROM AUTHOR]

Acute hyperinsulinaemias induced by insulin and stimulants of insulin secretion have been shown to cause a translocation of liver insulin receptors from the cell surface to the intracellular compartment, with little or no change in total receptor number. To determine whether a similar phenomenon occurs in chronic hyperinsulinaemic states, we have carried out a longitudinal study of total, cell surface and intracellular liver insulin receptors in genetically obese Zucker rats, with spontaneously develop hyperinsulinaemia. Liver plasma membranes, Golgi-endosomal fractions, a microsomal fraction and a total particulate fraction were isolated in 2-14-week old obese (fa/fa) rats and examined for specific insulin binding relative to lean (Fa/?) age-matched animals. In 16-day old rats, which were still normoinsulinaemic, insulin binding was unchanged. Later on, as hyperinsulinaemia developed, three sequential changes in insulin binding activity were observed: first, a 25-30% increase in Golgiendosomal fractions (20 days); then, a 50-60% decrease in Golgi-endosomal fractions (4-5 weeks); and finally, a 50% decrease in plasma membranes (11 weeks), microsomal fraction and total particulate fraction (14 weeks), accompanied by restoration in Golgi-endosomal fractions (8-11 weeks). Unlike insulin receptors, insulin extractable from Golgiendosomal fractions at 4-5 weeks was unchanged or increased. We conclude that, although an early increase in the endocytosis of liver insulin receptors may occur in hyperinsulinaemic Zucker rats, this mechanism does not account for the later decrease in cell surface receptors observed in these animals. [ABSTRACT FROM AUTHOR]

We identified a new Y243S mutation in the X-linked E1 α-PDH gene in a patient with pyruvate dehydrogenase complex (PDHc) deficiency. The activity in cultured fibroblasts was very low even in the presence of high thiamine pyrophosphate (TPP) concentrations, indicating that the defect could be due to decreased affinity of PDHc for TPP. [ABSTRACT FROM AUTHOR]