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PubMed2005

Evidence for sexual selection on structural plumage coloration in female eastern bluebirds (Sialia sialis).

Although the function of ornamental traits in males has been the focus of intensive research for decades, expression of such traits in females has received much less study. Eastern bluebirds (Sialia sialis) display structurally based ultraviolet/blue and melanin-based chestnut plumage, and in males this plumage coloration is related to both reproductive success and competitive ability. Compared to males, female bluebirds show a subdued expression of blue and chestnut ornamental coloration, and we used a combination of an aviary nutritional-stress experiment and four years of field data to test the hypothesis that coloration functions as a signal of female quality. First, we tested the effect of food intake on expression of structural and melanin coloration in female eastern bluebirds to determine whether structural or melanin coloration are condition-dependent traits. Females that were given ad libitum access to food displayed more ornamented structural coloration than females on a food-restricted diet, but there was no effect of the experiment on melanin ornamentation. Second, we used field data to assess whether female ornamentation correlated with measures of mate quality and parental effort. The structural coloration of females predicted first egg date, maternal provisioning rates, and measures of reproductive success. These data indicate that structural coloration is dependent on nutritional condition and suggest that sexual selection is acting on structurally based plumage coloration in female eastern bluebirds.

Age Factors↗
PubMed2006

Foraging biology predicts food web complexity.

Food webs, the networks of feeding links between species, are central to our understanding of ecosystem structure, stability, and function. One of the key aspects of food web structure is complexity, or connectance, the number of links expressed as a proportion of the total possible number of links. Connectance (complexity) is linked to the stability of webs and is a key parameter in recent models of other aspects of web structure. However, there is still no fundamental biological explanation for connectance in food webs. Here, we propose that constraints on diet breadth, driven by optimal foraging, provide such an explanation. We show that a simple diet breadth model predicts highly constrained values of connectance as an emergent consequence of individual foraging behavior. When combined with features of real food web data, such as taxonomic and trophic aggregation and cumulative sampling of diets, the model predicts well the levels of connectance and scaling of connectance with species richness, seen in real food webs. This result is a previously undescribed synthesis of foraging theory and food web theory, in which network properties emerge from the behavior of individuals and, as such, provides a mechanistic explanation of connectance currently lacking in food web models.

Animals↗
PubMed1991

[Food-borne outbreaks of gastroenteritis caused by small round structured viruses. 1. Four outbreaks of gastroenteritis associated with oyster consumption].

Between December 9, 1988 and January 28, 1989, there were four outbreaks of acute gastroenteritis in Saitama prefecture. Eighty-two of 123 persons (67%) attending four banquets in restaurants became ill: 44 cases attending three banquets were related to eating raw oysters, and 38 attending one banquet to eating sashimi. The most common symptoms were nausea, diarrhea, abdominal cramps, and vomiting. Average incubation periods were 29 to 32 hours long. Bacteriologic analysis of stool specimens did not reveal causative agents. Small round structured viruses were detected in fecal specimens from 19 of 39 ill persons (49%) by electron microscopy. In one of four outbreaks, the formation of antibody to small round structured virus in paired serum samples was detected by western blot test. Small round structured viruses were implicated as the etiologic agents in four outbreaks of acute gastroenteritis.

Acute Disease↗
PubMed2004

Impact of cleaning and disinfection agents on biofilm structure and on microbial transfer to a solid model food.

AIM: To determine how single cells and microcolonies transfer to food from open surfaces in the meat industry. METHODS AND RESULTS: Biofilms of four bacterial strains isolated from food processing surfaces were established on stainless steel substrates conditioned with meat exudate in the presence or absence of CaCl(2). Image analysis of the biofilms showed that the addition of calcium resulted in an increase of the number and size of microcolonies with two strains: Staphylococcus sciuri and Pseudomonas fluorescens. Image analysis of the biofilms of those two strains grown in the presence of calcium was performed before and after contacts with tryptone soya agar as a solid model food. For the biofilms treated or not with a chlorinated alkaline agent, where a decrease in surface coverage occurred, it was accompanied by a decrease in the percentage of the coverage accounted for by microcolonies (P(m)). Attachment strength was greater for P. fluorescens than for S. sciuri. When the P. fluorescens biofilms were treated with a solution containing glutaraldehyde, the contacts did not modify their structure. By contrast, their treatment with chlorinated alkaline resulted, after contacts, in the smallest coverage and P(m). With S. sciuri, a decrease in coverage after contacts always occurred and was the greatest for the untreated biofilms. CONCLUSIONS: After contacts between biofilms and a solid model food, microcolonies were preferentially detached compared with single cells. A chlorinated alkaline product either decreased biofilm attachment strength (P. fluorescens) or unexpectedly increased it (S. sciuri), whereas a glutaraldehyde-based disinfectant increased both attachment strength and microcolony cohesion. SIGNIFICANCE AND IMPACT OF THE STUDY: The contaminating potential of a surface depends not only on the level of contamination but also on the nature, structure and history of the contamination.

Bacterial Adhesion↗
PubMed1987

Chlordiazepoxide-induced selection of saccharin-flavoured food in the food-deprived rat.

Following a period of food-deprivation, adult male rats were given a choice between three sources of food in a 15 min test. All three consisted of a mash of powdered food and water; saccharin and quinine were added to two of them, respectively. Chlordiazepoxide (5 and 10 mg/kg, IP) significantly reduced the latency to begin eating, and also increased the overall level of food consumption. Its hyperphagic effect was due to a selective increase in ingestion of the saccharin-flavoured food, and was not due to a general increase in food consumption across all three food sources. Analysis of the micro-structure of feeding indicated that the increase in food intake depended upon an increase in the duration of individual bouts. Other feeding parameters were not significantly affected by chlordiazepoxide. These data suggest the CDP treatments affect feeding behaviour selectively, both in relation to the taste characteristics of the food, and also with regard to alterations in the micro-structure of the feeding responses.

Animals↗
PubMed1984

Activation of brain regions in rats during food-intake operant behavior.

The central nervous structures involved in bar pressing and feeding behavior during food-intake operant behavior were investigated in rats by the [14C]-deoxyglucose ( [14C]-DG) autoradiographic technique. During bar pressing behavior, the [14C]-DG incorporation increased in the sensory-motor cortex, ventromedial thalamus, zona incerta, pars reticulata of substantia nigra, ligular cortex of the cerebellum and the reticular formation of the medulla. On the other hand, an increase of the [14C]-DG incorporation induced by feeding behavior was observed in the fornix, medial forebrain bundle, parietal cortex, trigeminal nuclei and the solitary nuclei.

Animals↗
PubMed1989

Mutagenic nitrenes/nitrenium ions from azido-imidazoarenes and their structure-activity relationships.

New heterocyclic arylazides (azido-imidazoarenes) structurally related to the food mutagen/carcinogen 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ) have been prepared. Their photolysis yields nitrenes and/or nitrenium ions which induce mutations in Salmonella typhimurium. The relationships between the chemical structure and mutagenic activity of these species are the same as those found in our previous studies of the amino- and nitro-imidazoarenes. Therefore the efficiency of the reaction with DNA of the ultimate metabolite, the nitrene/nitrenium ion, is the critical step governing the mutagenic potency of the amino- and nitro-imidazoarenes. The efficiency of DNA-binding depends on the delocalization of the positive charge of the nitrenium ion or of the electron deficiency of the nitrene. It is typical of the N-1-substituted and N-3-substituted arenimidazolyl-nitrenium ions that they can form another nitrenium resonance structure very similar to the parent nitrenium ion structure. We suggest that this property of the nitrene/nitrenium ion, in combination with its aromatic structure facilitating carbonium ion resonance structures, is the basic reason for the extremely potent mutagenic activity of IQ and related food mutagens/carcinogens.

Amines↗
PubMed2004

Reduction of anxiety after restricted feeding in the rat: implication for eating disorders.

BACKGROUND: Eating-disorder patients exhibit not only abnormal eating attitudes but also pathologic anxiety-like behaviors. The specific nature of the relationship between dieting and anxiety-like behavior is unknown. METHODS: To investigate the adaptational changes that resulted from chronic restricted scheduled feeding (2-hour access per day for 2 weeks) and subsequent free refeeding, longitudinal changes in the microstructure of feeding behavior were studied in male rats. To study the relationship between restricted feeding and anxiety-like behavior, separate rats were tested in the elevated plus-maze under the following conditions: 1) free feeding; 2) acute food restriction (2-hour access for 1 day); 3) chronic food restriction (for 10 days); or 4) postrecovery (after 10 days of free feeding subsequent to chronic food restriction). RESULTS: The effects of chronic food restriction on meal structure diminished within a few days after refeeding. Decreased anxiety-like behavior was seen during acute and chronic food restriction and did not reflect nonspecific behavioral activation. Anxiolytic-like effects persisted after 10 days of refeeding. CONCLUSIONS: Chronic food restriction produced reductions in anxiety-like behavior that persisted beyond the normalization of food intake patterns. The findings might have etiologic and pathophysiologic relevance for the restrained eating pattern in eating-disorder patients with comorbid anxious symptoms.

Adaptation, Psychological↗
PubMed2004

Influence of the physical form of processed rice products on the enzymatic hydrolysis of rice starch in vitro and on the postprandial glucose and insulin responses in patients with type 2 diabetes mellitus.

The manufacturing processes used determined the physicochemical properties of the three kinds of rice food, garaeduk, bagsulgi, and cooked rice. The initial rate of hydrolysis by porcine pancreatic alpha-amylase (PPA) was affected by the food form. The firmer structure of garaeduk was apparently responsible for the difficulty in maceration, resulting in less digestion than with easily digestible food for the same maceration time. The initial rate of hydrolysis of each rice product by PPA increased with increasing maceration time in a Waring Blender for all of the processed rice products. The postprandial glucose and insulin responses to the three processed rice products were also studied in ten patients with type 2 diabetes mellitus (4 men and 6 women aged 56.8 +/- 2.3 yr; duration of diabetes, 3.6 +/- 1.2 yr; body mass index (BMI), 23.7 +/- 2.6 kg/m2; fasting serum glucose, 143.9 +/- 5.1 mg/dl; serum insulin, 20.8 +/- 2.2 microU/ml). Each subject ingested of the three rice foods after a 12-h overnight fast, and the serum glucose and insulin levels were measured over a 0-240 min period. The postprandial serum glucose and insulin levels at 90 min after ingesting bagsulgi and cooked rice were less than those at 60 min, while the levels at 90 min after ingesting garaeduk were higher than those at 60 min. Garaeduk also significantly decreased the incremental responses of glucose and insulin when compared with bagsulgi and cooked rice. The results suggest that garaeduk would be the most unlikely to increase the postprandial serum glucose and insulin levels among the three rice foods. The food form, which eventually differentiated each food by its specific surface area with the same degree of maceration because of the characteristic physical strength, therefore affected the rate of rice starch hydrolysis both in vitro and in vivo.

Amylases↗
PubMed1997

Balanced intakes of natural triglycerides for optimum nutrition: an evolutionary and phytochemical perspective.

Natural whole foods contain fats as structural components, and have a balance of polyunsaturated fat, monounsaturated fat, and saturated fat. Since we are still a Paleolithic species, adapted to eating only wild foods, it is difficult to justify the consumption of anything other than an overall balance of triglyceride/phospholipid types in an evolutionary sense. No natural fats are intrinsically good or bad--it is the proportions that matter. Variety is recommended in dietary lipid structure, degree of saturation, and chain length. Pathological n-3/n-6 polyunsaturated fat imbalance, obesity, and progressive glucose intolerance are consequences of adopting cereal grain based diets by both humans and livestock. Food processing and refining amplify these problems. Excessive concerns regarding polyunsaturated fat peroxidation in vivo are not warranted when trigylcerides are balanced and normal diets are consumed. Numerous phytochemicals present in unrefined oils, fruits, vegetables, and herbs afford significant protection from lipid peroxidation and chronic disease.

Animals↗
PubMed2006

Fluorescence spectroscopy as a tool for monitoring solubility and aggregation behavior of beta-lactoglobulin after heat treatment.

Denaturation and aggregation of whey proteins are of interest to the food and pharmaceutical industry due to the importance of final structure in functionality, impact on food texture, and the chemical stability of the final product. In this study, we demonstrate the potential of fluorescence spectrometry combined with multivariate chemometric methods for quantifying solubility and aggregation behavior of beta-lactoglobulin (beta-LG); a major whey protein and a frequent food ingredient. Heat-induced aggregation of beta-LG was studied under different conditions including pH, temperature and heating durations. Results showed very good agreement between the fluorescence-based predictions and measurements obtained by HPLC and gravimetric analysis regardless of the conditions. Standard normal variate (SNV), a signal preprocessing and filtering tool, was found to enhance the predictive accuracy and robustness of the fluorescence-based model.

Chromatography, High Pressure Liquid↗
PubMed2002

Heat-induced gels of egg white/ovalbumins from five avian species: thermal aggregation, molecular forces involved, and rheological properties.

Product processing (heating, pH change, etc.) usually alters protein structure, improves rheological properties, and gives a unique texture to foods. The thermal aggregation and structural properties of ovalbumins from five avian species were studied at different pH values by polyacrylamide gel electrophoresis (PAGE) and determinations of sulfhydryl group content and surface hydrophobicity. The results showed that sulfhydryl group content changed insignificantly in heat-denatured ovalbumins other than hen ovalbumin (pH-independent), and surface hydrophobicity markedly increased (pH-dependent) after heating, with a significant difference among species. Furthermore, it was demonstrated that the hydrophobic interaction and sulfhydryl-disulfide interchange reaction were necessary in the aggregation and cross-linking of gel networks. Creep tests were also used to characterize the gel network structures of various egg white/ovalbumins upon heating. The viscoelastic behavior of the ovalbumins of all species was dependent on pH values, and changed significantly with the phylogeny of these species. With increases in pH value (7.0-8.5), the heat-induced gels of ovalbumins gradually changed from turbid to translucent, the instantaneous modulus (E(0)) increased slightly and reached a nearly constant value, and the Newtonian modulus (etaN) increased significantly in each sample. The heated egg white from these five avian species also formed highly viscoelastic gels, with a good correlation of viscoelastic behavior between ovalbumin and egg white in corresponding species.

Animals↗
PubMed1999

Food processing and lipid oxidation.

Food lipids are principally triacylglycerides, phospholipids and sterols found naturally in most biological materials consumed as food and added as functional ingredients in many processed foods. As nutrients, lipids, especially triglycerides, are a concentrated caloric source, provide essential fatty acids and are a solvent and absorption vehicle for fat-soluble vitamins and other nutrients. The presence of fat significantly enhances the organoleptic perception of foods, which partly explains the strong preference and market advantage of fat-rich foods. As a class, lipids contribute many desirable qualities to foods, including attributes of texture, structure, mouthfeel, flavor and color. However, lipids are also one of the most chemically unstable food components and will readily undergo free-radical chain reactions that not only deteriorate the lipids but also: (a) produce oxidative fragments, some of which are volatile and are perceived as the off-flavors of rancidity, (b) degrade proteins, vitamins and pigments and (c) cross-link lipids and other macromolecules into non-nutritive polymers. Free-radical chain reactions are thermodynamically favorable, and as a result, evolutionary selection has strongly influenced the chemistry, metabolism and structure of biological cells to prevent these reactions kinetically. However, the loss of native structure and the death of cells can dramatically accelerate the deteriorative reactions of lipid oxidation. The effects of all processing steps, including raw product selection, harvesting, storage, refining, manufacturing and distribution, on the quality of lipids in the final commodity are considerable. Certain key variables now known to influence oxidative processes can be targeted to increase food lipid stability during and after processing. Retention of or addition of exogenous antioxidants is a well-known consideration, but the presence and activity of catalysts, the integrity of tissues and cells, the quantity of polyunsaturated lipids and the structural properties of the final food product, including total surface area of lipids, and the nature of surfactant materials all play important roles in final product stability.

Antioxidants↗
PubMed2006

Health foods and foods with health claims in Japan.

The terms 'nutraceuticals' and 'dietary or food supplements' are not very popular in Japan as compared to most of other countries. However, the concept of 'functional foods', which benefits the structure and function of the human body, is known as a result of research studies initiated on the health benefits of foods in 1984. The Ministry of Education organized a national research and development project to evaluate the functionalities of various foods. Researchers from diverse scientific fields succeeded to define new functions of food, successfully incorporating the previously recognized functions of nutrition, sensory/satisfaction and physiological effects of ingredients in foods. Some of the food manufacturers and distributors unfortunately capitalized on such food functionalities to promote 'health foods' by claiming drug-like effects and violating laws. In 1991, the Ministry of Health and Welfare (MHW) now as the Ministry of Health, Labor and Welfare (MHLW) introduced a 'foods for specified health uses' (FOSHU) system, for the control of such exaggerated and misleading claims. The other reason for such enforcement is due to an increase in the population of elderly people and lifestyle-related diseases that include obesity, diabetes mellitus, high blood pressure, cerebro- and cardiovascular diseases and cancer. In 2001, a new regulatory system, 'foods with health claims' (FHC) with a 'foods with nutrient function claims' (FNFC) system and newly established FOSHU was introduced. In addition, MHLW has changed the existing FOSHU, FNFC and other systems in 2005. Such changes include the new subsystems of FOSHU such as (1) standardized FOSHU, (2) qualified FOSHU and (3) disease risk reduction claims for FOSHU. In the present chapter, two guidelines that require good manufacturing practice (GMP) and self-investigative systems for ensuring the safety of raw materials used for products in the dosage forms such as capsules, tablets, etc. have been discussed. Furthermore, issues related to positioning and definition of supplements are also discussed in the light of the enhancement of understanding the beneficial roles that supplements may play for human health in Japan.

Consumer Product Safety↗
PubMed2004

Systematic studies of structure and physiological activity of alapyridaine. A novel food-born taste enhancer.

By application of taste dilution analysis (+)-(S)-1-(1-carboxyethyl)-5-hydroxy-2-(hydroxymethyl)-pyridinium inner salt was recently successfully identified as a multimodal taste enhancer in beef bouillon. While being taste-less on its own, this so-called alapyridaine was found to intensify the human perception of sweet, salty, and umami taste. To gain information on the molecular requirements of this novel class of taste enhancer, a range of structurally related pyridinium betaines were synthesized, purified, and their physiological activities sensorially evaluated. Removal or modification of the hydroxyl and the hydroxymethyl group, respectively, induced a loss in bioactivity, thus indicating the 2-(hydroxymethyl)-5-hydroxypyridinium moiety as an essential structural element for taste enhancement. Regarding the amino substituent, neither the prolongation or removal of the alkyl chain or the carboxy function in the 1-(1-carboxy-2-ethyl)-moiety, nor the incorporation of an additional carboxy function led to any active derivative, thus demonstrating that also the structure of the nitrogen substituent is rather conserved for taste enhancement. But substitution of the methyl group by a benzyl group yielded a compound showing similar taste enhancing activities as found for alapyridaine. Interestingly, additional insertion of glycine between the 1-(1-carboxy-2-phenylethyl)-moiety and the pyridinium ring resulted in a compound eliciting comparable taste enhancing effects as shown for the compound lacking the glycine spacer. In contrast to these multimodal taste enhancers, substitution of the alanine moiety in alapyridaine by an arginine moiety revealed an one-dimensional taste enhancer exclusively increasing the human sensitivity for salty taste.

Alanine↗
PubMed2005

A review of family and social determinants of children's eating patterns and diet quality.

With the growing problem of childhood obesity, recent research has begun to focus on family and social influences on children's eating patterns. Research has demonstrated that children's eating patterns are strongly influenced by characteristics of both the physical and social environment. With regard to the physical environment, children are more likely to eat foods that are available and easily accessible, and they tend to eat greater quantities when larger portions are provided. Additionally, characteristics of the social environment, including various socioeconomic and sociocultural factors such as parents' education, time constraints, and ethnicity influence the types of foods children eat. Mealtime structure is also an important factor related to children's eating patterns. Mealtime structure includes social and physical characteristics of mealtimes including whether families eat together, TV-viewing during meals, and the source of foods (e.g., restaurants, schools). Parents also play a direct role in children's eating patterns through their behaviors, attitudes, and feeding styles. Interventions aimed at improving children's nutrition need to address the variety of social and physical factors that influence children's eating patterns.

Child↗
PubMedDate not supplied

[Setting normal levels of benz(a)pyrene in foods].

In the paper, methodological requirements are formulated for validation of permissible levels of benz(a)pyrene (B(a)P) in foodstuffs. A list is submitted of allowable levels of this carcinogen in food products for the population of Ukraine, their specific values being dependent on the accepted tolerance daily done intake and on the structure of the standard food ration. Prevention of B(a)P formation and its elimination from the human habitat together with the use of the modern environmentally appropriate technologies designed to prepare food products will form a basis for stabilization of the permissible dose of the carcinogen, finding its way to the human body as a food component through dietary intake.

Benzo(a)pyrene↗