Considerations on growth characteristics of different pineapple varieties in Ivory Coast, Reunion Island and Caribbean Islands

Tendency in pineapple markets is to offer more and more varieties to the consumers as it is done for other products. Beside the references of 'Smooth Cayenne' and today 'MD-2' varieties, 'Queen' and new hybrids are also proposed for commercial production to the farmers. As consistency in production and quality is a key point for markets, it is important to know the behaviour of the different varieties at field level. Growth characteristics of 'MD-2', 'Smooth Cayenne' and 'Queen Victoria' have been assessed in different areas, such as on one hand in Côte d'Ivoire for 'Smooth Cayenne', 'MD-2', and on the other hand 'Queen Victoria' in La Reunion; additional data from Martinique have also been used for all varieties. Plant weight increases in a similar pattern for 'Smooth Cayenne', 'MD-2' and 'Flhoran 41', but is slower for the 'Queen' variety. 'D' leaves growth shows the classical sigmoid pattern for all the varieties. 'D' leaves weight is used as an index for forcing date determination. In Côte d'Ivoire on 'Smooth Cayenne' and 'MD-2', forcing is done when 'D' leaves reach 80 g fresh weight. At this stage plant weight is 2,0 kg and expected average fruit weight is 1.5 kg (standard for export). 'Flhoran 41' for the same plant weight, has a larger number of leaves and 'D' leaves weight is 75 g to harvest a fruit of 1.5 kg. 'Queen' shows a 'D' leaf weight of 50 g for a plant weight of 1.0 kg giving an average fruit weight of 700 g (air freight standard in La Reunion). The data give also a confirmation, if needed, that whatever the variety is, aerial suckers have faster growth than slips and the last ones have a faster growth than fruit crowns. A tentative growth model based on sum of temperature is proposed. It may be useful for determination of the date of forcing under standard growth conditions. (Texte intégral

Morphine activates neuroinflammation in a manner parallel to endotoxin

Opioids create a neuroinflammatory response within the CNS, compromising opioid-induced analgesia and contributing to various unwanted actions. How this occurs is unknown but has been assumed to be via classic opioid receptors. Herein, we provide direct evidence that morphine creates neuroinflammation via the activation of an innate immune receptor and not via classic opioid receptors. We demonstrate that morphine binds to an accessory protein of Toll-like receptor 4 (TLR4), myeloid differentiation protein 2 (MD-2), thereby inducing TLR4 oligomerization and triggering proinflammation. Small-molecule inhibitors, RNA interference, and genetic knockout validate the TLR4/MD-2 complex as a feasible target for beneficially modifying morphine actions. Disrupting TLR4/MD-2 protein–protein association potentiated morphine analgesia in vivo and abolished morphine-induced proinflammation in vitro, the latter demonstrating that morphine-induced proinflammation only depends on TLR4, despite the presence of opioid receptors. These results provide an exciting, nonconventional avenue to improving the clinical efficacy of opioids.Xiaohui Wang, Lisa C. Loram, Khara Ramos, Armando J. de Jesus, Jacob Thomas, Kui Cheng, Anireddy Reddy, Andrew A. Somogyi, Mark R. Hutchinson, Linda R. Watkins and Hang Yi

Structure-activity relationship in monosaccharide-based Toll-like receptor 4 (TLR4) antagonists

The structure-activity relationship was investigated in a series of synthetic TLR4 antagonists formed by a glucosamine core linked to two phosphate esters and two linear carbon chains. Molecular modeling showed that the compounds with 10, 12, and 14 carbons chains are associated with higher stabilization of the MD-2/TLR4 antagonist conformation than in the case of the C16 variant. Binding experiments with human MD-2 showed that the C12 and C14 variants have higher affinity than C10, while the C16 variant did not interact with the protein. The molecules, with the exception of the C16 variant, inhibited the LPS-stimulated TLR4 signal in human and murine cells, and the antagonist potency mirrored the MD-2 affinity calculated from in vitro binding experiments. Fourier-transform infrared, nuclear magnetic resonance, and small angle X-ray scattering measurements suggested that the aggregation state in aqueous solution depends on fatty acid chain lengths and that this property can influence TLR4 activity in this series of compounds

Toll-like receptor expression in C3H/HeN and C3H/HeJ mice during Salmonella enterica serovar Typhimurium infection

Here, we have investigated the mRNA expression of Toll-like receptor 2 (TLR-2), TLR-4, and MD-2 in spleens and livers of C3H/HeN mice (carrying wild-type TLR-4) and C3H/HeJ mice (carrying mutated TLR-4) in response to Salmonella infection. During Salmonella infections, TLR-4 is activated, leading to increased TLR-2 and decreased TLR-4 expression

Can systemic resistances contribute to ecologically based IPM control of nematodes in pineapple?

Pineapple monoculture and the use of pesticides reduced the biodiversity in the agrosystems and increased the imbalance between pathogenic and beneficial organisms. Non specific plant natural defenses may contribute to ecologically based IPM as an alternative to pesticides for nematode control in pineapple. Material and Methods: Two pineapple varieties, Smooth Cayenne (SC) and MD-2, received Elicitor treatment as soil applications of 50mL Methyl-jasmonate, 10-4 M, or Salicylic acid, 10-3 M, or Laminarin (? 1,3 Glucans), 37 g/L, followed by Nematodes inoculation: R. reniformis (5000/pot). Nematode populations growth was evaluated and enzymatic activities involved in plant defense: Catalase (CAT), Superoxide dismutase (SOD), Phenylalanine ammonialyase (PAL) and Lipoxigenase (LOX) were measured on non inoculated plants. Results: The nematode population growth was slowed down on the nematode tolerant variety MD-2 by Methyl-jasmonate and Salicylic acid, p values were 0.003, 0.021. Most of the decreases ranged 30 to 70%. Methyl-jasmonate and Laminarin induced significative enzymatic activities variations; Salicylic acid treatment did not. Most remarkable were the decreases of Catalase and PAL activities. Meanwhile LOX activity increased significantly and a slight increase in SOD was also observed. Discussion: Pineapple has been able to set up defenses against nematodes after elicitor treatments,but tolerant and sensitive varieties did not react equally. LOX, PAL and some of the oxidative enzymes (CAT) can be used to characterize the physiological changes in the plant. Is the MD-2 response a Systemic Resistance? Similar experiments using a split-root system have confirmed this (data to be published). LOXs control the Methyl-jasmonate pathway, meanwhile PAL controls the Salicylic acid and phenylpropanoids pathways. The LOX activity increase may reflect an enhanced biosynthesis of the signal molecule Methyl-jasmonate, characterizing an Induced Systemic Resistance set up. On the contrary, the decrease of PAL activity is less clear as it means less phenylpropanoids involved in plant defense. But it may also reflect a necessary balance between Salicylic acid and Methyl-jasmonate pathways. (Résumé d'auteur

MD-2 is required for disulfide HMGB1-dependent TLR4 signaling

Innate immune receptors for pathogen- and damage-associated molecular patterns (PAMPs and DAMPs) orchestrate inflammatory responses to infection and injury. Secreted by activated immune cells or passively released by damaged cells, HMGB1 is subjected to redox modification that distinctly influences its extracellular functions. Previously, it was unknown how the TLR4 signalosome distinguished between HMGB1 isoforms. Here we demonstrate that the extracellular TLR4 adaptor, myeloid differentiation factor 2 (MD-2), binds specifically to the cytokine-inducing disulfide isoform of HMGB1, to the exclusion of other isoforms. Using MD-2–deficient mice, as well as MD-2 silencing in macrophages, we show a requirement for HMGB1-dependent TLR4 signaling. By screening HMGB1 peptide libraries, we identified a tetramer (FSSE, designated P5779) as a specific MD-2 antagonist preventing MD-2–HMGB1 interaction and TLR4 signaling. P5779 does not interfere with lipopolysaccharide-induced cytokine/chemokine production, thus preserving PAMP-mediated TLR4–MD-2 responses. Furthermore, P5779 can protect mice against hepatic ischemia/reperfusion injury, chemical toxicity, and sepsis. These findings reveal a novel mechanism by which innate systems selectively recognize specific HMGB1 isoforms. The results may direct toward strategies aimed at attenuating DAMP-mediated inflammation while preserving antimicrobial immune responsiveness

Surface Analysis of OFE-Copper X-Band Accelerating Structures and Possible Correlation to RF Breakdown Events

X-band accelerator structures meeting the Next Linear Collider (NLC) design requirements have been found to suffer vacuum surface damage caused by radio frequency (RF) breakdown, when processed to high electric-field gradients. Improved understanding of these breakdown events is desirable for the development of structure designs, fabrication procedures, and processing techniques that minimize structure damage. RF reflected wave analysis and acoustic sensor pickup have provided breakdowns localization in RF structures. Particle contaminations found following clean autopsy of four RF-processed travelling wave structures, have been catalogued and analyzed. Their influence on RF breakdown, as well as that of several other material-based properties, will be discussed.Comment: 21 pages, 8 figures, 4 tables, Submitted to JVST A as a proceeding of the 50th AVS conference (Baltimore, MD, 2-7 Nov 2003

Physicochemical quality, antioxidant compounds and activity of MD-2 pineapple fruit at five ripening stages

Although Malaysia is one of the important pineapple fruit producing and exporting country, the production of MD-2 pineapple fruit only started in 2009. Pineapple fruit has been harvested at different ripening stages for different markets. The information on Malaysian grown MD-2 pineapple fruit quality is lacking. Therefore this work was carried out with the aim to determine physicochemical quality, antioxidant compounds and activity of MD-2 pineapple fruit at five ripening stages. Ripening stage affected physicochemical quality of MD-2 pineapple fruit. Soluble solids concentration of MD-2 pineapple fruit increased from 15.41 to 18.02%SSC when fruit ripened from stage 1 to 4 and no significant difference was found in fruit between stage 4 and 5. The ascorbic acid content decreased while total carotenoids content increased as ripening stage advanced. The total phenolic content of both 80% methanol and water extraction solvents increased significantly as fruit ripened from stage 1 to 3 and reduced as fruit ripened to stage 5. The antioxidant activity of MD-2 pineapple fruit as assayed using DPPH, FRAP and ABTS showed similar trend as total phenolic content. These results suggest that ripening stage affect MD-2 pineapple fruit quality and nutritional values

Differential expression of Toll-like receptor 4 in healthy and diseased human gingiva

BACKGROUND AND OBJECTIVE: Lipopolysaccharide (LPS)-mediated signaling in host cells involves Toll-like receptor 4 (TLR4) accessory molecules, including LPS-binding protein (LBP), cluster of differentiation 14 (CD14) and lymphocyte antigen 96 (MD-2). However, expression of these innate defense molecules in various compartments of the human periodontium is unclear. The aim of this study was to investigate the expression profile of TLR4 in human gingiva. MATERIAL AND METHODS: Human gingival biopsies were collected from healthy gingival or chronic periodontitis tissue. Primary gingival keratinocytes and fibroblasts were cultured. Immunohistochemical analysis for TLR4 was performed. Transcripts of TLR4, MD-2, CD14 and LBP, and their protein products, were examined using RT-PCR, immunoprecipitation and immunoblotting. The interactions between these molecules in keratinocytes and fibroblasts were investigated by co-immunoprecipitation. RESULTS: TLR4 immunoreactivity was found in healthy gingival epithelium and periodontitis tissue, and appeared to be lower in junctional epithelium ( p </= 0.01). Fibroblasts and inflammatory cells stained more strongly for TLR4 in diseased periodontal tissues (p < 0.001). Three TLR4 splicing variants, two MD-2 splicing variants and one CD14 mRNA were expressed by gingival keratinocytes and fibroblasts. Expression of TLR4, CD14 and MD-2 proteins was detected in keratinocytes and fibroblasts in vitro. TLR4 protein from gingival keratinocytes and fibroblasts could be co-immunoprecipitated with CD14 or MD-2, suggesting an association between the related molecules in vivo. LBP transcript was detected in gingival biopsies, but not in primary cultures of gingival keratinocytes or fibroblasts. CONCLUSION: TLR4, CD14 and MD-2, but not LBP, are expressed in human gingival keratinocytes and fibroblasts. The TLR4 expression level in the junctional epithelium appeared to be lowest within the periodontal epithelial barrier.postprin