Determinants of intention to purchase chicken in Italy: the role of consumer risk perception and trust in different information sources

The article investigates how purchasing intentions among a sample of Italian consumers are influenced by different levels of risk perception and their trust in food-safety information provided by different sources such as the food industry, government agencies, or consumers' associations. The assessment of the determinants of intention to purchase was carried out by estimating a causal model for the chicken case in which attitudes, subjective norms, and perceived risk play a major role in determining buyer's behavior. In particular, the role of trust in influencing risk perception is highlighted either as a general construct or as specific constructs targeting food chain, policy actors, and the media. [EconLit citations: Q130, Q190, D120]. (C) 2008 Wiley Periodicals, Inc.

Estimators in capture-recapture studies with two sources

This paper investigates the applications of capture-recapture methods to human populations. Capture-recapture methods are commonly used in estimating the size of wildlife populations but can also be used in epidemiology and social sciences, for estimating prevalence of a particular disease or the size of the homeless population in a certain area. Here we focus on estimating the prevalence of infectious diseases. Several estimators of population size are considered: the Lincoln-Petersen estimator and its modified version, the Chapman estimator, Chao's lower bound estimator, the Zelterman's estimator, McKendrick's moment estimator and the maximum likelihood estimator. In order to evaluate these estimators, they are applied to real, three-source, capture-recapture data. By conditioning on each of the sources of three source data, we have been able to compare the estimators with the true value that they are estimating. The Chapman and Chao estimators were compared in terms of their relative bias. A variance formula derived through conditioning is suggested for Chao's estimator, and normal 95% confidence intervals are calculated for this and the Chapman estimator. We then compare the coverage of the respective confidence intervals. Furthermore, a simulation study is included to compare Chao's and Chapman's estimator. Results indicate that Chao's estimator is less biased than Chapman's estimator unless both sources are independent. Chao's estimator has also the smaller mean squared error. Finally, the implications and limitations of the above methods are discussed, with suggestions for further development.

Characterization of a gamma-aminobutyric acid transport system of rhizobium leguminosarum bv. viciae 3841

Spontaneous mutants of Rhizobium leguminosarum bv. viciae 3841 were isolated that grow faster than the wild type on gamma-aminobutyric acid (GABA) as the sole carbon and nitrogen source. These strains (RU1736 and RU1816) have frameshift mutations (gtsR101 and gtsR102, respectively) in a GntR-type regulator (GtsR) that result in a high rate of constitutive GABA transport. Tn5 mutagenesis and quantitative reverse transcription-PCR showed that GstR regulates expression of a large operon (pRL100242 to pRL100252) on the Sym plasmid that is required for GABA uptake. An ABC transport system, GtsABCD (for GABA transport system) (pRL100248-51), of the spermidine/putrescine family is part of this operon. GtsA is a periplasmic binding protein, GtsB and GtsC are integral membrane proteins, and GtsD is an ATP-binding subunit. Expression of gtsABCD from a lacZ promoter confirmed that it alone is responsible for high rates of GABA transport, enabling rapid growth of strain 3841 on GABA. Gts transports open-chain compounds with four or five carbon atoms with carboxyl and amino groups at, or close to, opposite termini. However, aromatic compounds with similar spacing between carboxyl and amino groups are excellent inhibitors of GABA uptake so they may also be transported. In addition to the ABC transporter, the operon contains two putative mono-oxygenases, a putative hydrolase, a putative aldehyde dehydrogenase, and a succinate semialdehyde dehydrogenase. This suggests the operon may be involved in the transport and breakdown of a more complex precursor to GABA. Gts is not expressed in pea bacteroids, and gtsB mutants are unaltered in their symbiotic phenotype, suggesting that Bra is the only GABA transport system available for amino acid cycling.

Evidence of a possible role for Lys-gamma 3-MSH in the regulation of adipocyte function

Lys-gamma 3-MSH is a melanocortin peptide derived from the C-terminal of the 16 kDa fragment of POMC. The physiological role of Lys-gamma 3-MSH is unclear, although it has previously been shown that, although not directly steroidogenic, it can act to potentiate the steroidogenic response of adrenal cortical cells to ACTH. This synergistic effect appears to be correlated with an ability to increase the activity of hormone sensitive lipase (HSL) and therefore the rate of cholesterol ester hydrolysis. Ligand binding studies have suggested that high-affinity binding sites for Lys-gamma 3-MSH exist in the adrenal gland and a number of other rat tissues that express HSL, including adipose, skeletal muscle and testes. To investigate the hypothesis that Lys-gamma 3-MSH may play a wider role in cholesterol and lipid metabolism, we tested the effect of Lys-gamma 3-MSH on lipolysis, an HSL-mediated process, in 3T3-L1 adipocytes. In comparison with other melanocortin peptides, Lys-gamma 3-MSH was found to be a potent stimulator of lipolysis. It was also able to phosphorylate HSL at key serine residues and stimulate the hyper-phosphorylation of perilipin A. The receptor through which the lipolytic actions of Lys-gamma 3-MSH are being mediated is not clear. Attempts to characterise this receptor suggest that either the pharmacology of the melanocortin receptor 5 in 3T3-L1 adipocytes is different from that described when expressed in heterologous systems or the possibility that a further, as yet uncharacterised, receptor exists.

Role of gamma-MSH peptides in the regulation of adrenal steroidogenesis

Alpha-, beta- and gamma-melanocyte stimulating hormones (MSHs) are peptides derived from the ACTH precursor, pro-opiomelanocortin. All three peptides have been highly conserved throughout evolution but their exact biological function in mammals is still largely obscure. In recent years, there has been a surge of interest in alpha-MSH and its role in the regulation of feeding. Gamma-MSH by contrast has been shown to be involved in the regulation of adrenal steroidogenesis and also has effects on the cardiovascular and renal systems. This review will provide an overview of the role that gamma-MSH peptides play in the regulation of adrenal steroidogenesis. (c) 2005 Elsevier Inc. All rights reserved.

The role of the melanocortin 3 receptor in mediating the effects of gamma-MSH peptides on the adrenal

The pro-opiomelanocortin (POMC)-derived peptides, pro-gamma-MSH (16K fragment), and Lys-gamma(3)-MSH, have been shown to potentiate the steroidogenic action of corticotrophin (ACTH) on the adrenal cortex. Using a continuously perfused adrenal cell column system, we have tested the hypothesis that gamma-MSH peptides exert their effect through the Melanocortin 3 Receptor (MC3-R), since this is the only known receptor to have high affinity for gamma-MSH peptides and has been suggested to be expressed in the rat adrenal. To investigate this hypothesis we tested whether the MC3-R agonist MTII and antagonist SHU9119 could mimic or block the actions of pro-gamma-MSH. We found that MTII could not mimic, and SHU9119 could not block pro-gamma-MSH mediated potentiation of ACTH-induced steroidogenesis. These results suggest that the MC3-R is not involved in mediating the potentiation effect, adding further evidence to the argument that another melanocortin receptor exists.

Use of essential and molecular dynamics to study gamma B-crystallin unfolding after non-enzymic post-translational modifications

Essential and Molecular Dynamics (ED/MD) have been used to model the conformational changes of a protein implicated in a conformational disease-cataract, the largest cause of blindness in the world-after non-enzymic post-translational modification. Cyanate modification did not significantly alter flexibility, while the Schiff's base adduct produced a more flexible N-terminal domain, and intra-secondary structure regions, than either the cyanate adduct or the native structure. Glycation also increased linker flexibility and disrupted the charge network. A number of post-translational adducts showed structural disruption around Cys15 and increased linker flexibility; this may be important in subsequent protein aggregation. Our modelling results are in accord with experimental evidence, and show that ED/MD is a useful tool in modelling conformational changes in proteins implicated in disease processes. (C) 2003 Published by Elsevier Ltd.

Conservation and sustainable use of wild species as sources of new ornamentals

While only about 1-200 species are used intensively in commercial floriculture (e.g. carnations, chrysanthemums, gerbera, narcissus, orchids, tulips, lilies, roses, pansies and violas, saintpaulias, etc.) and 4-500 as house plants, several thousand species of herbs, shrubs and trees are traded commercially by nurseries and garden centres as ornamentals or amenity species. Most of these have been introduced from the wild with little selection or breeding. In Europe alone, 12 000 species are found in cultivation in general garden collections (i.e. excluding specialist collections and botanic gardens). In addition, specialist collections (often very large) of many other species and/or cultivars of groups such as orchids, bromeliads, cacti and succulents, primulas, rhododendrons, conifers and cycads are maintained in several centres such as botanic gardens and specialist nurseries, as are 'national collections' of cultivated species and cultivars in some countries. Specialist growers, both professional and amateur, also maintain collections of plants for cultivation, including, increasingly, native plants. The trade in ornamental and amenity horticulture cannot be fully estimated but runs into many billions of dollars annually and there is considerable potential for further development and the introduction of many new species into the trade. Despite this, most of the collections are ad hoc and no co-ordinated efforts have been made to ensure that adequate germplasm samples of these species are maintained for conservation purposes and few of them are represented at all adequately in seed banks. Few countries have paid much attention to germplasm needs of ornamentals and the Ornamental Plant Germplasm Center in conjunction with the USDA National Plant Germplasm System at The Ohio State University is an exception. Generally there is a serious gap in national and international germplasm strategies, which have tended to focus primarily on food plants and some forage and industrial crops. Adequate arrangements need to be put in place to ensure the long- and medium-term conservation of representative samples of the genetic diversity of ornamental species. The problems of achieving this will be discussed. In addition, a policy for the conservation of old cultivars or 'heritage' varieties of ornamentals needs to be formulated. The considerable potential for introduction of new ornamental species needs to be assessed. Consideration needs to be given to setting up a co-ordinating structure with overall responsibility for the conservation of germplasm of ornamental and amenity plants.

Nanostructure formation in poly(gamma-benzyl-L-glutamate)-poly(ethylene glycol)-poly(gamma-benzyl-L-glutamate) triblock copolymers in the solid state

The morphology in the solid state of a series of triblock copolymers comprising a poly(ethylene glycol) (PEG) midblock and symmetric poly(gamma-benzyl-L-glutamate) (PBLG) end blocks has been studied using X-ray scattering and microscopy techniques. Transmission electron microscopy (TEM) on samples selectively stained with uranyl acetate provided clear assignment of morphologies for as-cast and annealed samples. The thickness of both PEG and PBLG domains was in good agreement with calculations based on the conformations of the respective chains, allowing for the crystal or amorphous state of PEG and the a-helical or P-sheet structure of the PBLG. Atomic force microscopy provided complementary information on surface morphology for several samples that was in good agreement with the structure observed by TEM. A morphology diagram was constructed. Cylindrical structures were observed for ordered samples with low f(PBLG), whereas at higher f(PLBG) there was evidence for broken lamellar and "hockey puck" nanostructures. Regular lamellae were observed for intermediate compositions.

Supramolecular beta-sheet and nanofibril formation by self-assembling tripeptides containing an N-terminally located gamma-aminobutyric acid residue

Three terminally protected tripeptides Boc-gamma-Abu-Val-Leu-OMe 1, Boc-gamma-Abu-Leu-Phe-OMe 2 and Boc-gamma-Abu-Val-Tyr-OMe 3 (gamma-Abu = gamma-aminobutyric acid) each containing an N-terminally positioned gamma-aminobutyric acid residue have been synthesized, purified and studied. FT-IR studies of all these peptides revealed that these peptides form intermolecularly hydrogen bonded supramolecular beta-sheet structures. Peptides 1, 2 and 3 adopt extended backbone beta-strand molecular structures in crystals. Crystal packing of all these peptides demonstrates that these beta-strand structures self-assemble to form intermolecularly H-bonded parallel beta-sheet structures. Peptide 3 uses a side chain tyrosyl -OH group as an additional hydrogen bonding functionality in addition to the backbone CONH groups to pack in crystals. Transmission electron microscopic studies of all peptides indicate that they self-assemble to form nanofibrillar structures of an average diameter of 65 nm. These peptide fibrils exhibit amyloid-like behavior as they bind to a physiological dye Congo red and show a characteristic green-gold birefringence under polarizing microscope.

Flavanol monomer-induced changes to the human faecal microflora

We have investigated the bacterial-dependent metabolism of (-)-epicatechin and (+)-catechin using a pH-controlled, stirred, batch-culture fermentation system reflective of the distal region of the human large intestine. Incubation of (-)-epicatechin or (+)-catechin (150mg/l or 1000mg/l) with faecal bacteria, led to the generation of 5-(3,4'-dihydroxyphenyl)-gamma-valerolactone, 5-phenyl-gamma-valerolactone and phenylpropionic acid. However, the formation of these metabolites from (+)-catechin required its initial conversion to (+)-epicatechin. The metabolism of both flavanols occurred in the presence of favourable carbon sources, notably sucrose and the prebiotic fructo-oligosaccharides, indicating that bacterial utilisation of flavanols also occurs when preferential energy sources are available. (+)-Catechin incubation affected the growth of select microflora, resulting in a statistically significant increase in the growth of the Clostridium coccoides-Eubacterium rectale group, Bifidobacterium spp. and Escherichia coli, as well as a significant inhibitory effect on the growth of the C. histolyticum group. In contrast, the effect of (-)-epicatechin was less profound, only significantly increasing the growth of the C. coccoides-Eubacterium rectale group. These potential prebiotic effects for both (+)-catechin and (-)-epicatechin were most notable at the lower concentration of 150 mg/l. As both (-)-epicatechin and (+)-catechin were converted to the same metabolites, the more dramatic change in the growth of distinct microfloral populations produced by (+)-catechin incubation may be linked to the bacterial conversion of (+)-catechin to (+)-epicatechin. Together these data suggest that the consumption of flavanol-rich foods may support gut health through their ability to exert prebiotic actions.

Clostridium bolteae sp. nov., isolated from human sources

Seven obligately anaerobic, gram-positive, rod-shaped, spore-forming organisms isolated from human sources were characterized using phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing showed that the strains were genetically highly related to each other (displaying >99% sequence similarity) and represent a previously unknown sub-line within the Clostridium coccoides rRNA group of organisms. Strains of the unidentified bacterium used carbohydrate as fermentable substrates, producing acetic acid and lactic acid as the major products of glucose metabolism. The closest described species to the novel bacterium corresponded to Clostridium clostridioforme, although a 16S rRNA sequence divergence of 3% demonstrated they represent different species. Genomic DNA-DNA pairing studies confirmed the separateness of the unknown species and Clostridium clostridioforme. Based on phenotypic and phylogenetic evidence, it is therefore proposed that the unknown bacterium, be classified as Clostridium bolteae sp. nov. The type strain of Clostridium bolteae is WAL 16351(T) (= ATCC(T) = BAA-613(T), CCUG(T) = 46953(T)).