At its most fundamental, cancer is a genetic disease resulting from inherited or acquired mutations in tumour suppressor genes and proto-oncogenes. Environmental factors, including ingested food components, interact with genetic inheritance to determine individual cancer risk. There is growing evidence that the immune system exerts selective pressure during neoplastic development. Tumour cells that evade this immunosurveillance because they are non-antigenic or because they defend themselves successfully against immune attack have a survival advantage. Effective chemopreventative agents will include dietary components that enhance the immune system's ability to identify transformed cells and to target them for apoptosis.

Animals↗

PubMed2000

The effect of pH and ligand exchange on the redox properties of blue copper proteins.

A study of the structure and redox properties of the copper site in azurins by means of EXAFS, NMR, redox titrations, potentiometry, equilibrium cyclic voltammetry and rapid scan voltammetry on protein films is reported. The results are discussed in light of existing theories on structure and function of type-1 copper sites. The exit and entry of electrons take place through the C-terminal histidine ligand of the copper. The hydrophobic patch through which this residue penetrates the protein surface plays an important role in partner docking (cf. The rim of the porphyrin ring sticking through the surface of the cytochromes-c). We find no experimental evidence for strain around the metal site. The active centre is able to maintain ET activity even in the presence of fairly gross disturbances of the site structure. The analysis of the thermodynamics of the redox reaction shows that the protein matrix and the solvent play an important role in 'tuning' the redox potential around a "design" value of around 300 mV at room temperature. The metal site appears "designed" to stabilise the Cu(II) instead of the Cu(I) form. The remarkable evolutionary success of the blue copper proteins is ascribed to the sturdy overall beta-sandwich structure of the protein in combination with a metal site that is structurally adaptable because three of its four ligands are located on a loop. The electronic "gate" that occurs in the middle of a hydrophobic patch allows for fine tuning of the docking patch for recognition purposes.

Bacterial Proteins↗

PubMed2000

Aromatherapy for deaf and deafblind people living in residential accommodation.

This article looks at ways in which aromatherapy and therapeutic massage have been found to be beneficial for a group of deaf and deafblind adults with special needs, living in residential accommodation. Our basic aim is to promote confidence and communication as well as enhancing a sense of well-being through the judicial use of aromatic plant materials and therapeutic massage. Aromatherapy sessions have become an accepted enjoyable and therapeutic part of the residents' lifestyle. It is our belief that this gentle, non-invasive therapy can benefit deaf and deafblind people, especially as their intact senses can be heightened. This paper explores both professional and caring issues related to the use of aromatherapy in this environment.

Adult↗

PubMed2000

Dope 'em up and ship 'em out: issues in mental health care.

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Cooperative Behavior↗

PubMed1997

Inhibition of Listeria monocytogenes and Salmonella enteriditis by combinations of plant oils and derivatives of benzoic acid: the development of synergistic antimicrobial combinations.

This study describes inhibitory properties of combinations of oil of fennel, oil of anise or oil of basil with either benzoic acid or methyl-paraben against Listeria monocytogenes and Salmonella enteriditis. Micro-organisms were cultured at 37 degrees C in broth and viable counts measured over a 48-h period. S. enteriditis was particularly sensitive to inhibition by a combination of oil of anise, fennel or basil with methyl-paraben where there was < 10 CFU/ml after 1 h. L. monocytogenes was less sensitive to inhibition by each combination however there was a significant reduction in growth of 4-8 log by combinations of all oils and methyl-paraben at 8, 24 and 48 h. Synergistic inhibition by one or more combinations was evident against each micro-organism.

Anti-Bacterial Agents↗

PubMed1995

Sensitivity to abscisic acid of guard-cell K+ channels is suppressed by abi1-1, a mutant Arabidopsis gene encoding a putative protein phosphatase.

Abscisic acid (ABA) modulates the activities of three major classes of ion channels--inward- and outward-rectifying K+ channels (IK,in and IK,out, respectively) and anion channels--at the guard-cell plasma membrane to achieve a net efflux of osmotica and stomatal closure. Disruption of ABA sensitivity in wilty abi1-1 mutants of Arabidopsis and evidence that this gene encodes a protein phosphatase suggest that protein (de)-phosphorylation contributes to guard-cell transport control by ABA. To pinpoint the role of ABI1, the abi1-1 dominant mutant allele was stably transformed into Nicotiana benthamiana and its influence on IK,in, IK,out, and the anion channels was monitored in guard cells under voltage clamp. Compared with guard cells from wild-type and vector-transformed control plants, expression of the abi1-1 gene was associated with 2- to 6-fold reductions in IK,out and an insensitivity of both IK,in and IK,out to 20 microM ABA. In contrast, no differences between control and abi1-1 transgenic plants were observed in the anion current or its response to ABA. Parallel measurements of intracellular pH (pHi) using the fluorescent dye 2',7'-bis(2-carboxyethyl)-5-(and -6)-carboxyfluorescein (BCECF) in every case showed a 0.15- to 0.2-pH-unit alkalinization in ABA, demonstrating that the transgene was without effect on the pHi signal that mediates in ABA-evoked K+ channel control. In guard cells from the abi1-1 transformants, normal sensitivity of both K+ channels to and stomatal closure in ABA was recovered in the presence of 100 microM H7 and 0.5 microM staurosporine, both broad-range protein kinase antagonists. These results demonstrate an aberrant K+ channel behavior--including channel insensitivity to ABA-dependent alkalinization of pHi--as a major consequence of abi1-1 action and implicate AB11 as part of a phosphatase/kinase pathway that modulates the sensitivity of guard-cell K+ channels to ABA-evoked signal cascades.

Abscisic Acid↗

PubMed1994

Selective block by alpha-dendrotoxin of the K+ inward rectifier at the Vicia guard cell plasma membrane.

The efficacy and mechanism of alpha-dendrotoxin (DTX) block of K+ channel currents in Vicia stomatal guard cells was examined. Currents carried by inward- and outward-rectifying K+ channels were determined under voltage clamp in intact guard cells, and block was characterized as a function of DTX and external K+ (K+o) concentrations. Added to the bath, 0.1-30 nM DTX blocked the inward-rectifying K+ current (IK,in), but was ineffective in blocking current through the outward-rectifying K+ channels (IK,out) even at concentrations of 30 nM. DTX block was independent of clamp voltage and had no significant effect on the voltage-dependent kinetics for IK,in, neither altering its activation at voltages negative of -120 mV nor its deactivation at more positive voltages. No evidence was found for a use dependence to DTX action. Block of IK,in followed a simple titration function with an apparent K1/2 for block of 2.2 nM in 3 mM K+o. However, DTX block was dependent on the external K+ concentration. Raising K+o from 3 to 30 mM slowed block and resulted in a 60-70% reduction in its efficacy (apparent Ki = 10 mM in 10 nM DTX). The effect of K+ in protecting IK,in was competitive with DTX and specific for permeant cations. A joint analysis of IK,in block with DTX and K+ concentration was consistent with a single class of binding sites with a Kd for DTX of 240 pM. A Kd of 410 microM for extracellular K+ was also indicated. These results complement previous studies implicating a binding site requiring extracellular K+ (K1/2 approximately 1 mM) for IK,in activation; they parallel features of K+ channel block by DTX and related peptide toxins in many animal cells, demonstrating the sensitivity of plant plasma membrane K+ channels to nanomolar toxin concentrations under physiological conditions; the data also highlight one main difference: in the guard cells, DTX action appears specific to the K+ inward rectifier.

Binding Sites↗

PubMed1986

Aromatherapy.

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Humans↗