Water sorption-desorption in conifer cuticles: The role of lignin.

Current information on the type and amount of biopolymers present in the epidermis of conifer species is still insufficient. This work presents the detailed morphology and chemical composition of Araucaria bidwillii cuticle after selective treatments to remove the different types of biopolymers. After removal of the waxes, cutin and polar hydrolyzable components, a lignin-like fraction, which makes up 25% of the initial cuticle weight, was identified by GC-MS and infrared spectroscopy.

Steam-explosion of olive stones: hemicellulose solubilization and enhancement of enzymatic hydrolysis of cellulose.

Olive stones (whole stones and seed husks in fragments) were processed by steam-explosion under different experimental conditions of temperature and time, 200-236 degrees C for 2-4 min, with or without previous acid impregnation with 0.1%, H2SO4 (w/w). This paper examines the solubilization of hemicelluloses and their molecular weight distribution.

Olive fruit cell wall: degradation of cellulosic and hemicellulosic polysaccharides during ripening.

Cellulose and hemicelluloses obtained from the cell walls of partially depectinated olives have been studied at three stages of ripening (green, cherry, and black). Hemicelluloses were fractionated into two groups, the amounts of which diminished during ripening: those soluble in 4% KOH diminished between the cherry and black stages, whereas those soluble in 24% KOH did so between the green and cherry stages. Arabinoxylans, xyloglucans, and homo- and/or rhamnogalacturonans to a lesser extent were present in these fractions.

Specific heat determination of plant barrier lipophilic components: biological implications.

The specific heat of isolated plant cuticles and their corresponding cuticular waxes have been measured for the physiological temperature in the range of 273-318 K at regular intervals. C(p) values ranged from 1.5 up to 4 J K(-1) g(-1) indicating a high cohesion, at the molecular level, of the molecular lipophilic components that constitute the plant cuticle.

Olive fruit cell wall: degradation of pectic polysaccharides during ripening.

Olive fruits at three stages of ripening (green, cherry, and black) have been studied. After cell wall isolation, the compositions of the cell wall and that of the phosphate-soluble polysaccharides were determined. In cell walls, decreases in arabinose, xylose, glucose, and uronic acid levels were observed, together with a slight increase in mannose on ripening.

Pharmacological characterization of almotriptan: an indolic 5-HT receptor agonist for the treatment of migraine.

Almotriptan (3-[2-(dimethylamino)ethyl]-5-(pyrrolidin-1-ylsulfonylmethyl )-1H-indo le) has been studied in several models predictive of activity and selectivity at 5-HT receptors. Almotriptan showed low nanomolar affinity for the 5-HT(1B) and 5-HT(1D) receptors in several species, including the human, while affinity for 5-HT receptors other than 5-HT(1B/1D) was clearly less. Affinity for 5-HT(7) and 5-HT(1A) receptors was approximately 40 and 60 times lower than that for 5-HT(1B/1D) receptors, respectively.

Synergistic inhibition of HIV-1 in activated and resting peripheral blood mononuclear cells, monocyte-derived macrophages, and selected drug-resistant isolates with nucleoside analogues combined with a natural product, resveratrol.

Resveratrol (trans-3,5,4;-trihydroxystilbene) is a phytoalexin present in grapes, wine, and certain plants, which has recently been reported to possess properties that may protect against atherosclerosis, certain cancers, and inflammation. We now report that resveratrol (RV) synergistically enhances the anti-HIV-1 activity of the nucleoside analogues zidovudine (AZT), zalcitabine (ddC), and didanosine (ddI). RV at 10 microM was not toxic to cells, and by itself reduced viral replication by 20% to 30%.

Investigating plant lipid biopolymers.

This paper presents a review of the biological importance and occurrence of plant cutin, the main lipid biopolymer in higher plants. Its chemical composition and structure are reviewed and a short laboratory practical exercise on the extraction, purification and qualitative analysis of fruit cutin is presented.

Synthesis and biological evaluation of 3,4-diaryloxazolones: A new class of orally active cyclooxygenase-2 inhibitors.

A series of 3,4-diaryloxazolones were prepared and evaluated for their ability to inhibit cyclooxygenase-2 (COX-2). Extensive structure-activity relationship work was carried out within this series, and a number of potent and selective COX-2 inhibitors were identified. The replacement of the methyl sulfone group on the 4-phenyl ring by a sulfonamide moiety resulted in compounds with superior in vivo antiinflammatory properties.

Cardiotoxicity of histamine and the possible role of histamine in the arrhythmogenesis produced by certain antihistamines.

Since 1990 it has repeatedly been reported that some histamine H1 receptor antagonists (e.g. terfenadine and astemizole) are able to produce ventricular arrhythmias (e.

Turnover of white asparagus cell wall polysaccharides during postharvest storage.

The main polysaccharides involved in asparagus cell wall turnover have been identified. Homogalacturonans are lost from both the apical and basal sections of the spear. Galactans are mobilized from the cellulose residue of the apical section and recovered in the KOH-soluble fractions while they are lost from the cellulose residue of the basal section.

Postharvest changes in white asparagus cell wall during refrigerated storage.

The postharvest changes of the white asparagus cell wall have been studied in relation to the toughening process along the length of a spear that was divided into three sections: apical, middle, and basal. Polysaccharides underwent significant turnover during storage. Uronic acid concentration decreased in all sections and in almost all polysaccharide fractions, while neutral sugars increased very slightly in the apical section, decreased in the middle, and increased in the basal one.

Improved germination under osmotic stress of tobacco plants overexpressing a cell wall peroxidase.

The cell wall is a fundamental component in the response of plants to environmental changes. To directly assess the role of the cell wall we have increased the expression and activity of a cell wall associated peroxidase (TPX2), an enzyme involved in modifying cell wall architecture. Overexpression of TPX2 had no effect on wild-type development, but greatly increased the germination rate under high salt or osmotic stress.

Abacavir and mycophenolic acid, an inhibitor of inosine monophosphate dehydrogenase, have profound and synergistic anti-HIV activity.

The use of inhibitors of purine nucleoside metabolism has been advocated for the treatment of HIV-1 infection. Abacavir is the first clinically available guanosine analogue HIV-1 reverse transcriptase inhibitor, and the most potent nucleoside analogue yet developed. Mycophenolic acid (MA), a specific inhibitor of lymphocyte proliferation that is currently in use in organ transplantation, acts on inosine monophosphate dehydrogenase to block conversion of inosine monophosphate to guanosine monophosphate.

Gain of Bcl-2 is more potent than bax loss in regulating mammary epithelial cell survival in vivo.

The impact of gain of Bcl-2 function on mammary epithelial cell survival was compared with loss of Bax function during the two stages of mammary gland involution. Bcl-2 gain of function reduced apoptosis 50% during the first stage and increased cell survival 70% during the second stage. Complete loss of Bax reduced apoptosis by 20% during the first stage without second stage effect.

Characterization and biosynthesis of non-degradable polymers in plant cuticles.

The structure and monomeric composition of the highly aliphatic and non-saponifiable fraction of cutans isolated from the leaf cuticles of Agave americana L. and Clivia miniata Reg. have been elucidated.

Triggering of effector functions on a CD8+ T cell clone upon the aggregation of an activatory CD94/kp39 heterodimer.

Some T lymphocytes express the CD94 Ag, which is known to form heterodimers with members of the NKG2 family. We have studied the expression pattern and function of CD94 heterodimers in different alphabeta or gammadelta T cell clones. Most of the CD94+NKG2A- T cells have a low to intermediate expression of CD94 Ag.

CCR5 genotype and HIV-1 infection in perinatally-exposed infants.

The CCR5 chemokine receptor is required by non-syncytium HIV-1 strains to infect target cells. A 32 base pair deletion (delta32) in the CCR5 gene causes a structural CCR5 modification that does not permit HIV-1 entry into cells. The rate of the CCR5 delta32 was investigated in 137 children born from HIV-infected mothers.

Water hydration in cutinized cell walls: a physico-chemical analysis.

Water sorption by plant cuticular membrane isolates, mainly identified as polysaccharides, after selective extraction of the lipid components waxes and cutin was measured over the whole range of water activity. From water sorption isotherm, the strengths of water binding and water clustering were estimated. Data obtained by differential scanning calorimetry and Fourier-transform and near infrared spectroscopy confirmed the existence of water molecules in different macromolecular environments.