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PubMed2002

Determination of trace isoflavone phytoestrogens in biological materials by capillary electrochromatography.

Capillary electrochromatography using a specialty monolithic matrix was utilized in developing a rapid and highly efficient separation of isoflavones in biological materials. Without a preconcentration technique, it is relatively easy to reach ppm-ppb concentrations of these compounds in soy-based foods and verify them structurally using a photodiode array detector. With on-column preconcentration, we were able to measure low-ppb levels in human serum. Using blood samples from human volunteers, whose diet was supplemented by a soy-based product, the method has been validated for high-throughput screening of isoflavones in clinical studies.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed2005

Novel tempeh (fermented soyabean) isoflavones inhibit in vivo angiogenesis in the chicken chorioallantoic membrane assay.

Anti-angiogenic strategies are emerging as an important tool for the treatment of cancer and inflammatory diseases. In the present investigation we isolated several isoflavones from a tempeh (fermented soyabean) extract. The isolated isoflavones were identified as 5,7,4'-trihydroxyisoflavone (genistein), 7,4'-dihydroxyisoflavone (daidzein), 6,7,4'-trihydroxyisoflavone (factor 2), 7,8,4'-trihydroxyisoflavone (7,8,4'-TriOH) and 5,7,3',4'-tetrahydroxyisoflavone (orobol). The effects on angiogenesis of these isoflavones were evaluated in the chicken chorioallantoic membrane assay; their capacity to inhibit vascular endothelial growth factor-induced endothelial cell proliferation and expression of the Ets 1 transcription factor, known to be implicated in the regulation of new blood vessel formation, were also investigated. We found that all isoflavones inhibited angiogenesis, albeit with different potencies. Compared with negative controls, which slightly inhibited in vivo angiogenesis by 6.30 %, genistein reduced angiogenesis by 75.09 %, followed by orobol (67.96 %), factor 2 (56.77 %), daidzein (48.98 %) and 7,8,4'-TriOH (24.42 %). These compounds also inhibited endothelial cell proliferation, with orobol causing the greatest inhibition at lower concentrations. The isoflavones also inhibited Ets 1 expression, providing some insight into the molecular mechanisms of their action. Furthermore, the chemical structure of the different isoflavones suggests a structure-activity relationship. Our present findings suggest that the new isoflavones might be added to the list of low molecular mass therapeutic agents for the inhibition of angiogenesis.

Angiogenesis Inhibitors↗

PubMed2003

Mandibular condyle movement during mastication of foods.

This study evaluated the mandibular condyle displacement on the working side while masticating certain foods with different textures. For referencing the mandibular condyle movement, the range of voluntary border movement of the mandibular condyle was determined based on the analysis of the sagittal, left lateral and right lateral border motion using Posselt's figure. The test foods consisted of cheese, peanuts, and beef jerky. During mastication of cheese and peanuts, the amount of displacement of the mandibular condyle in all directions was within the range of border movement. Significant posterior and superior shifts of the mandibular condyle were observed during mastication of beef jerky, compared with the findings obtained during border movement. Accordingly, it is suggested that prolonged mastication of hard fibrous foods, may stimulate the temporomandibular joint structure and mandibular dysfunction patients should limit their intake of such foods.

Adult↗

PubMed2006

Hormone fatty acid modifications: gram negative bacteria and vertebrates demonstrate common structure and function.

Bacteria are known to regulate diverse physiological processes through a mechanism called quorum sensing (QS). Prokaryotes communicate by extracellular signalling compounds, i.e. autoinducers (acyl homoserine lactone, AHL of Gram negative bacteria) or pheromones (post-translationally modified peptides of Gram positive bacteria), which activate genetic pathways when they reach a sufficient concentration (QS). A large number of Gram-negative quorum-sensing systems studied so far utilize N-acyl homoserine lactones as signal molecules. In vertebrates small synthetic molecules called growth hormone secretagogues (GHSs) stimulate the release of growth hormone (GH) from the pituitary. GH release is stimulated by hypothalamic GH-releasing hormone (GHRH) and ghrelin (endogenous ligand of the GHS-receptor, GHS-R). Ghrelin is a 28-amino acid peptide, in which the serine-3 (Ser3) is n-octanoylated, and this modification is essential for ghrelin's activity. Ghrelin is the first known case of a peptide hormone modified by a fatty acid. The major active form of ghrelin is a 28-amino acid peptide with octanoylated Ser3; one of the more represented bacterial autoinducers is the N-Octanoyl-DL-homoserine lactone (C8-HL) molecule. The authors hypothesize that Gram-negative bacteria and vertebrates have a functional similarity in the search of food and an important structural homology of AHL and ghrelin for the highly conserved Serine-acylated motive in both molecules. Our suggestions could help one to understand the convergent origin and the biologic meaning of the Serine-acylated group in these organisms, a biologic meaning very important due to the high conservation in two kingdoms which are so different.

Amino Acid Sequence↗

PubMed2002

The contemporary diet in France: "de-structuration" or from commensalism to "vagabond feeding".

Data collected from a sample of working individuals lunching at staff cafeterias were analysed to characterise contemporary food habits in terms of meal structure, eating outside meals, and other aspects of the organization of the daily food intake. Discrepancies were found between individuals' ideas of a proper meal and their actual practices. This brings to light some contradictions between conceptions underlying the contemporary diet and the more traditional idea of a structured meal. Analysis of the eater's search for a balanced diet from a cultural and historical viewpoint opens avenues of research common to both the social sciences and food science.

Adult↗

PubMedDate not supplied

[Interrelation between the food spectrum of perch fry (Perca fluvatilis L.) and macrozoobenthos structure in experimental mesocosms].

In experimental ecosystems that accommodate perch fry (Perca fluviatilis), significant structural changes within the benthic communities occurred under the effect of fish feeding on oligochaetes and on the larvae of chidonomids and other insects. Perch fry began to consume benthic animals at early developmental stages (C1-C2). The transition to regular feeding under experimental condition occurred at the D2-E stage (days 30-40), when the benthic community reached a developmental peak. The quantitative parameters characterizing the compositions of perch stomach contents and the main groups of zoobenthos closely correlated with each other. The dynamics of quantitative parameters of these animal groups (except for mollusks) proved to be determined both by the specific features of their life cycles and by the degree of consumption.

Animals↗

PubMed2002

High selectivity of human tissue transglutaminase for immunoactive gliadin peptides: implications for celiac sprue.

Celiac Sprue is an HLA DQ2 (or DQ8)-associated autoimmune disorder of the human small intestine that is induced by dietary exposure to wheat gliadin and related proteins from barley, rye, and possibly other food grains. Recently, tissue transglutaminase (tTGase)-catalyzed deamidation of gliadin peptides has been shown to increase their potency for activating patient-derived, gliadin-specific T cells, suggesting that tTGase plays a causative role in the onset of an inflammatory response to toxic food grains. To dissect the molecular recognition features of tTGase for gluten derived peptides, the regioselectivity and steady-state kinetics of tTGase-catalyzed deamidation of known immunogenic peptides were investigated. The specificity of recombinant human tTGase for all immunogenic peptides tested was comparable to and, in some cases, appreciably higher than the specificity for its natural substrate. Although each peptide was glutamine-rich, tTGase exhibited a high degree of regioselectivity for a particular glutamine residue in each peptide. This selectivity correlated well with Q --> E substitutions that have earlier been shown to enhance the immunogenicity of the corresponding gliadin peptides. The specificity of tTGase toward homologues of PQPQLPY, a sequence motif found in immunodominant gliadin peptides, was analyzed in detail. Remarkably, the primary amino acid sequences of wheat-, rye-, and barley-derived proteins included many single-residue variants of this sequence that were high-affinity substrates of tTGase, whereas the closest homologues of this sequence found in rice, corn, or oat proteins were much poorer substrates of tTGase. (Rice, corn, and oats are nontoxic ingredients of the Celiac diet.) No consensus sequence for a high-affinity substrate of tTGase could be derived from our data, suggesting that the secondary structures of these food-grain peptides were important in their recognition by tTGase. Finally, under steady-state turnover conditions, a significant fraction of the tTGase active site was covalently bound to a representative high-affinity immunogenic gliadin peptide, suggesting a common mechanism by which cells responsible for immune surveillance of the intestinal tract recognize and generate an antibody response against both gliadin and tTGase. In addition to providing a quantitative framework for understanding the role of tTGase in Celiac Sprue, our results lay the groundwork for the design of small molecule mimetics of gliadin peptides as selective inhibitors of tTGase.

Binding Sites↗

PubMed1985

Learning: neural analysis in the isolated brain of a previously trained mollusc, Pleurobranchaea californica.

The neural manifestations of food avoidance learning in the mollusc, Pleurobranchaea, survive the surgical reduction of the preparation to the nearly isolated brain. These manifestations include increased synaptic inhibition and reduced synaptic excitation of the phasic paracerebral feeding command interneurons (PCps) in the brain in response to food stimulation of chemosensory structures left attached to the brain. The same changes are not evident, however, in brains removed from naive, control or satiated specimens. Therefore the nearly isolated brain preparation permits analysis of the cellular substrates of learning in relative isolation from non-associative motivational variables. The isolated brain preparation is here used to show that the increased synaptic inhibition consequent to associative training is distributed not only to the PCps but also to their identified central presynaptic inputs, including other identified feeding command interneurons (PSEs and ETIIs; ref. 21). The decrease in PCp excitation is explained in part by a training-induced inhibition of excitatory inputs to the PCps, and in part by a training-induced reduction in the efficacy of an identified polysynaptic excitatory pathway presynaptic to the PCps.

Animals↗

PubMed1993

Dose-response in an outbreak of non-bacterial food poisoning traced to a mixed seafood cocktail.

An outbreak of non-bacterial food poisoning presumed due to small round, structured viruses (SRSV) occurred at a national conference. A detailed postal survey of all conference attenders was carried out to ascertain the cause of the outbreak and 355 questionnaires were returned. Univariate analysis showed that mussels in the seafood cocktail were the likely vehicle of infection. A dose-response relationship between the amount of seafood cocktail consumed and the risk of illness was demonstrated. Dose-response has not previously been documented in a food-borne outbreak due to small round structured virus. Detailed quantitative food histories can be useful in eliciting dose-response relationships and may be crucial in establishing the vehicle of infection when investigating food poisoning following consumption of a set-menu meal. Their use should be considered in other outbreak situations.

Disease Outbreaks↗

PubMed2006

[Cutaneous symptoms after ingestion of pollen-associated foodstuffs].

The molecular basis of pollen-related food allergy is the marked similarity in sequence and structure of allergenic proteins in pollens and food plants. In affected patients, specific IgE antibodies are primarily directed against pollen allergens but then recognize homologous allergens in plant food. In Central and Northern Europe up to 80% of birch pollen allergic subjects suffer from a food allergy, in particular to stone- and pip fruits, nuts and vegetables. The main clinical manifestation of pollen-related food allergy is the oral allergy syndrome (OAS), a contact urticaria of the oral mucosa. Other features include contact urticaria of the hands in those handling the foods, as well as generalized urticaria and angioedema following ingestion. The impact of pollen-related food allergy on the severity and course of atopic eczema remain to be elucidated.

Administration, Oral↗

PubMed2005

Balancing food availability and hydrodynamic constraint: phenotypic plasticity and growth in Simulium noelleri blackfly larvae.

Organisms through phenotypic plasticity can cope with multiple changed environmental conditions. Theory predicts that animals in streams and rivers should be able to balance demands of the needs to obtain food efficiently and to adjust response to hydrodynamic variability. This study examined effects of variations in food availability and current velocity on the feeding structure and growth rate of Simulium noelleri blackfly larvae. The larvae developed larger labral fans and more rays under slow current and low food regimes than in fast current and high food conditions. In both fast and slow current regimes, growth rates were higher and development periods to the final-instar stage were shorter in high food treatments. The estimated flux rates of food particles through labral fans under high food treatments for both fast and slow current regimes were higher than those under low food treatments. Although both food and current velocity appeared to have selected for flexibility of feeding structure and growth rate, food availability was a more important factor for phenotypic and developmental plasticity than current velocity. The results indicate a strong link between environmental changes in food availability and current velocity, phenotypic plasticity, and growth rate of S. noelleri. This study suggests that plasticity of ecomorphs with macroevolutionary significance may play a role in the early evolutionary stages of blackfly larvae.

Adaptation, Physiological↗

PubMed1998

The street food culture of Guatemala City: a case study from a downtown, urban park.

This study investigated the structure and environment of 31 street food vendors in an urban park in the downtown area of Guatemala City. Vendors were interviewed and observed in order to assess the quality, safety, and accessibility of street food. The street food vending in the park consisted of five types: whole meal, snack, beverage, fruits, and carts. A great variety of typical Guatemalan meals, as well as ready-to-eat fruits and hot dog chapin (hot dog with cabbage and avocado cream), were found in the park. The food preparation and handling revealed inadequacies concerning the hygiene. Circumstances, such as the lack of portable water near the vending site and unhygienic sanitary facilities, supported the transmission of pathogens. The clientele was of all ages, and included female as well as the male purchasers. Typical clients came from the surrounding area, i.e. the employees of civil and private offices, commercial businesses, and the non-food vendors of the park. Comparing the economy of street food with the definition of very poor in Guatemala, the prices on the street were often above the daily money needed for a basic food basket. However, a special clientele were the very poor, such as the street children and handicapped people, who earned their meals by helping out at the vending sites. Mainly female street food vendors were found at the whole meal, snack, and refreshment sites whereas men sold predominantly at the carts. For all of the vendors, it was the main source of income and for many families the only one.

Child↗

PubMed1993

Activation, travel distance, and environmental change influence food carrying in rats with hippocampal, medial thalamic and septal lesions: implications for studies on hoarding and theories of hippocampal function.

Rats transport food from exposed areas to covered areas where they eat it or leave it. Although there is evidence that limbic structures play a role in food transport, their role is controversial. Here it was found that although many rats with large hippocampal, septal/diagonal band of Broca or dorsomedial thalamic lesions did not carry food but ate it where they found it, a few presentations of an auditory stimulus could restore food carrying. Once restored, most features of food carrying in hippocampal rats were normal in relation to food presentation schedules, deprivation levels, ambient illumination, circadian cycles, food size, and eating times. Nevertheless, food carrying impairments re-emerged when the testing environment was changed. Hippocampal rats were also excessively responsive to increases in travel distance and stopped carrying food at distances over which control rats would still carry large food pellets. Auditory stimulation did not restore food carrying over long travel distances. The findings that sensory stimulation, environmental change, and travel distance influence food carrying probabilities in rats with limbic system lesions is discussed in relation to research on limbic control of food hoarding and theories of limbic system function.

Animals↗

PubMed2006

Single nucleotide polymorphism analysis of the enterocin P structural gene of Enterococcus faecium strains isolated from nonfermented animal foods.

The bacteriocins produced by two lactic acid bacteria isolated from nonfermented fresh meat and fish, respectively, and exhibiting a remarkable antilisterial activity, were characterized. Bacteriocinogenic strains were identified as Enterococcus faecium and the maximum bacteriocin production by both strains was detected in the stationary phase of growth. The activity against Listeria monocytogenes was maintained in pH range of 3-7 and was stable in both strains after heating at 100 or 121 degrees C. The genes coding for enterocin P were detected, isolated, and sequenced in both E. faecium strains. They exhibited DNA/DNA homology in the 87.1-97.2% range with respect to the other four enterocin P genes reported so far. Three single nucleotide polymorphism events, silent at the amino acid level, were detected at nucleotide positions 45 (G/A), 75 (A/G), and 90 (T/C) in E. faecium LHICA 28-4 and may explain the differences reported for those loci in other enterocin P-producing E. faecium strains. This work provides the first description of enterocin P-producing E. faecium strains in nonfermented foodstuffs and, in the case of E. faecium LHICA 51, the first report of an enterocin P-producing strain isolated from fish so far.

Amino Acid Sequence↗

PubMed2004

Textural quality assessment for fresh fruits and vegetables.

Academically, quantitative measurement of texture is essential for the study of the chemical and physiological mechanisms of texture. Commercially, quantitative measurement of texture is essential to ensure the quality of produce at packout. The diversity of tissues involved, the variety of attributes required to fully describe textural properties, and the changes in these attributes as the product ripens and senesces contribute to the complexity of texture measurement. Texture is a human assessment of the structural elements of a food. It is generally accepted that texture relates primarily to mechanical properties, so instrumental measurements relate mainly to mechanical properties. Fruits and vegetables exhibit viscoelastic behavior under mechanical loading, which means that the force, distance, and time involved in loading determine the value of any measurement. Because of their viscoelastic character, every effort should be made to hold the speed of the test constant in manual texture measurements and the rate of loading should be specified and controlled in mechanized measurements. There are many types of mechanical loading: puncture, compression, shearing, torsion (twisting), extrusion, crushing, tension, bending, vibration, and impact. The most widely used texture measurement for fruits and vegetables, after manual squeezing of course, is the Magness-Taylor fruit firmness test, which measures the maximum force to puncture the product in a specified way. The Kramer shear or shear-compression test is widely used in the processed foods industry, but is less commonly used by horticulturists. Nondestructive methods are highly desired both for sorting and for postharvest research. Compression tests of excised tissue pieces are frequently used in research. Nondestructive testing using impact, vibrational behavior, light scattering, and optical methods are being investigated but none has been widely accepted to date. Multiple instrumental measurements may be necessary to adequately the diversity of textural attributes sensed by the human consumer.

Fruit↗

PubMed1996

Genetics of subtilin and nisin biosyntheses: biosynthesis of lantibiotics.

Several peptide antibiotics have been described as potent inhibitors of bacterial growth. With respect to their biosynthesis, they can be divided into two classes: (i) those that are synthesized by a non-ribosomal mechanism, and (ii) those that are ribosomally synthesized. Subtilin and nisin belong to the ribosomally synthesized peptide antibiotics. They contain the rare amino acids dehydroalanine, dehydrobutyrine, meso-lanthionine, and 3-methyllanthionine. They are derived from prepeptides which are post-translationally modified and have been termed lantibiotics because of their characteristic lanthionine bridges (Schnell et al. 1988). Nisin is the most prominent lantibiotic and is used as a food preservative due to its high potency against certain gram-positive bacteria (Mattick & Hirsch 1944, 1947; Rayman & Hurst 1984). It is produced by Lactococcus lactis strains belonging to serological group N. The potent bactericidal activities of nisin and other lantibiotics are based on depolarization of energized bacterial cytoplasmic membranes. Breakdown of the membrane potential is initiated by the formation of pores through which molecules of low molecular weight are released. A trans-negative membrane potential of 50 to 100 mV is necessary for pore formation by nisin (Ruhr & Sahl 1985; Sahl et al. 1987). Nisin occurs as a partially amphiphilic molecule (Van de Ven et al. 1991). Apart from the detergent-like effect of nisin on cytoplasmic membranes, an inhibition of murein synthesis has also been discussed as the primary effect (Reisinger et al. 1980). In several countries nisin is used to prevent the growth of clostridia in cheese and canned food. The nisin peptide structure was first described by Gross & Morall (1971), and its structural gene was isolated in 1988 (Buchman et al. 1988; Kaletta & Entian 1989). Nisin has two natural variants, nisin A, and nisin Z, which differ in a single amino acid residue at position 27 (histidin in nisin A is replaced by asparagin in nisin Z (Mulders et al. 1991; De Vos et al. 1993). Subtilin is produced by Bacillus subtilis ATCC 6633. Its chemical structure was first unravelled by Gross & Kiltz (1973) and its structural gene was isolated in 1988 (Banerjee & Hansen 1988). Subtilin shares strong similarities to nisin with an identical organization of the lanthionine ring structures (Fig. 1), and both lantibiotics possess similar antibiotic activities. Due to its easy genetic analysis B. subtilis became a very suitable model organism for the identification and characterization of genes and proteins involved in lantibiotic biosynthesis. The pathway by which nisin is produced is very similar to that of subtilin, and the proteins involved share significant homologies over the entire proteins (for review see also De Vos et al. 1995b). The respective genes have been identified adjacent to the structural genes, and are organized in operon-like structures (Fig. 2). These genes are responsible for post-translational modification, transport of the modified prepeptide, proteolytic cleavage, and immunity which prevents toxic effects on the producing bacterium. In addition to this, biosynthesis of subtilin and nisin is strongly regulated by a two-component regulatory system which consists of a histidin kinase and a response regulator protein.

Amino Acid Sequence↗

PubMed2006

Sublethal effects of three pesticides on larval survivorship, growth, and macromolecule production in the aquatic midge, Chironomus tentans (diptera: chironomidae).

Effects of long-term exposure to each of three pesticides including atrazine, DDT, and chlorpyrifos on larval survivorship, growth, and macromolecule (total body protein and RNA) production were evaluated in the aquatic midge, Chironomus tentans, under laboratory conditions. Newly hatched larvae were exposed to atrazine at 30 and 150 microg/L, DDT at 0.01 and 0.05 microg/L, or chlorpyrifos at 0.02 and 0.10 microg/L throughout one life cycle. Larval survivorship was evaluated at 20 d and the end of the test, and larval growth at 20 d. Chlorpyrifos at 0.1 microg/L reduced the midge survivorship by 67% after 20-d exposure. However, neither atrazine nor DDT affected larval survivorship. The ash-free dry weight of midge larvae exposed to chlorpyrifos at 0.1 microg/L was 1.5-fold greater than that of the control whereas neither atrazine nor DDT showed a significant effect on the ash-free dry weight. In addition, exposures of midges to chlorpyrifos at 0.1 microg/L increased the adult emergence rate by 81% as compared to the control although the actual number of adults that emerged from chlorpyrifos-treated larvae was significantly decreased. Both the increased ash-free dry weight of larvae and increased adult emergence rate were likely caused by reduced competition for both food and space among the survivors due to increased larval mortality. Although neither total protein nor total RNA production was significantly affected in larvae exposed to each pesticide for 20 d, a significantly higher number of males over females (ratio = 4) emerged from midges exposed to DDT at 0.05 microg/L. Our study indicates that chronic exposure to low concentrations of chlorpyrifos and DDT results in significant mortality of midge larvae and alteration of the sex ratio of adult emergence, respectively. Because midges are important components of the food web, our results suggest that effects elicited directly or indirectly by long-term pesticide exposures may potentially disrupt both food chains and community structure in aquatic environments.

Animals↗

PubMed2000

A dynamic energy budget model based on partitioning of net production.

We formulate a Dynamic Energy Budget (DEB) model for the growth and reproduction of individual organisms based on partitioning of net production (i.e. energy acquisition rate minus maintenance rate) between growth and energy reserves. Reproduction uses energy from reserves. The model describes both feeding and non-feeding stages, and hence is applicable to embryos (which neither feed nor reproduce), juveniles (which feed but do not reproduce), and adults (which commonly both feed and reproduce). Embryonic growth can have two forms depending on the assumptions for acquisition of energy from yolk. By default, when the energy acquisition rate exceeds the maintenance rate, a fixed proportion of the resulting net production is spent on growth (increase in structural biomass), and the remaining portion is channelled to the reserves. Feeding organisms, however, modulate their allocation of net production energy in response to their total energy content (energy in the reserves plus energy bounded to structural biomass). In variable food environment an organism alternates between periods of growth, no-growth, and balanced-growth. In the latter case the organism adopts an allocation strategy that keeps its total energy constant. Under constant environmental conditions. the growth of a juvenile is always of von Bertalanffy type. Depending on the values of model parameters there are two long-time possibilities for adults: (a) von Bertalanffy growth accompanied by reproduction at a rate that approaches zero as the organism approaches asymptotic size, or (b) abrupt cessation of growth at some finite time, following which, the rate of reproduction is constant. We illustrate the model's applicability in life history theory by studying the optimum values of the energy allocation parameters for constant environment and for each of the dynamic regimes described above.

Animals↗