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PubMedDate not supplied

[Lantibiotics].

Lantibiotics synthesized by gram positive bacteria (Staphylococcus, Streptococcus, Bacillus, genera) are a special group of polycyclic polypeptides constituted of protein amino acids and unusual amino acids (i.e. lanthionine, beta-methyllantionine etc.) these last ones exhibiting interchain thioeter bridges and ring structures. Some lantibiotics are already used in medical therapy (nisin, gallidermin, epidermin) as well as for food preservation (nisin). Their special structures and synthesis have focused substantial scientific interest, the lantibiotics proving to be ideal experimental models not only for microbiology but also for biochemistry, molecular biology, gene technology and protein engineering in the purpose to get more insights in the fundamental aspects of the cell biology.

Animals↗
PubMed1998

Chemical changes during extrusion cooking. Recent advances.

Cooking extruders process a variety of foods, feeds, and industrial materials. Greater flexibility in product development with extruders depends upon understanding chemical reactions that occur within the extruder barrel and at the die. Starch gelatinization and protein denautration are the most important reactions during extrusion. Proteins, starches, and non-starch polysaccharides can fragment, creating reactive molecules that may form new linkages not found in nature. Vitamin stability varies with vitamin structure, extrusion conditions, and food matrix composition. Little is known about the effects of extrusion parameters on phytochemical bioavailability and stability. Reactive extrusion to create new flavor, antioxidant and color compounds will be an area of interest in the future.

Cooking↗
PubMed1988

Neuropeptide Y: brain localization and central effects on plasma insulin levels in chicks.

A rich network of NPY-like immunoreactive fibers was found in the paraventricular nucleus and the ventromedial region of the hypothalamus juxtapositioned to the third ventricle, including the median eminence. Brain regions, areas or nuclei found densely innervated by NPY-like immunoreactive fibers included the olfactory bulb region, septal area, organum vasculosum of the lamina terminalis, preoptic periventricular nucleus, hypothalamic periventricular nucleus, medial suprachiasmatic nucleus, subseptal (subfornical) organ, ventromedial hypothalamic nucleus, infundibular nucleus and nucleus tractus solitarius. NPY-like containing perikarya were localized within the hippocampus, bed nucleus of the stria terminalis and surrounding the nucleus rotundus and nucleus of the basal optic root. Since the immunocytochemical study showed that NPY was localized in brain structures known to alter food intake and the compound is a member of the pancreatic polypeptide family, a second study was designed to determine if the neuropeptide altered plasma concentrations of insulin, glucagon and glucose following intracerebroventricular administration. It was found that NPY significantly increased plasma concentration of insulin. It is proposed that two reasons why NPY is such a potent orexigenic agent is that the paraventricular nucleus and structures surrounding the third ventricle throughout the ventromedial hypothalamic region show high levels of NPY-like immunoreactivity. Secondly, NPY effects an increase in plasma insulin in the periphery.

Animals↗
PubMed2000

Metabolic compensation during high energy output in fasting, lactating grey seals (Halichoerus grypus): metabolic ceilings revisited.

Lactation is the most energetically expensive period for female mammals and is associated with some of the highest sustained metabolic rates (SusMR) in vertebrates (reported as total energy throughput). Females typically deal with this energy demand by increasing food intake and the structure of the alimentary tract may act as the central constraint to ceilings on SusMR at about seven times resting or standard metabolic rate (SMR). However, demands of lactation may also be met by using a form of metabolic compensation such as reducing locomotor activities or entering torpor. In some phocid seals, cetaceans and bears, females fast throughout lactation and thus cannot offset the high energetic costs of lactation through increased food intake. We demonstrate that fasting grey seal females sustain, for several weeks, one of the highest total daily energy expenditures (DEE; 7.4 x SMR) reported in mammals, while progressively reducing maintenance metabolic expenditures during lactation through means not explained by reduction in lean body mass or behavioural changes. Simultaneously, the energy-exported in milk is progressively increased, associated with increased lipoprotein lipase activity in the mammary gland, resulting in greater offspring growth. Our results suggest that females use compensatory mechanisms to help meet the extraordinary energetic costs of lactation. Additionally, although the concepts of SusMR and ceilings on total DEE may be somewhat different in fasting lactating species, our data on phocid seals demonstrate that metabolic ceilings on milk energy output, in general, are not constrained by the same kind of peripheral limitations as are other energy-consuming tissues. In phocid seals, the high ceilings on DEE during lactation, coupled with metabolic compensation, are undoubtedly important factors enabling shortened lactation.

Animals↗
PubMed2001

Lipid transfer proteins and 2S albumins as allergens.

Plant lipid transfer proteins, a widespread family of proteins, have been recently identified as important food allergens. Their common structural features, such as eight conserved cysteines forming disulfide bridges, basic isoelectric point and high similarity in amino acid sequence, are the basis of allergic clinical cross-reactivity. This has been demonstrated for the LTP allergens of the Prunoideae subfamily, whose similarity is about 95% as demonstrated for the purified allergens of peach, apricot, plum and apple. A relevant aspect is the existence of sequence homology of LTPs of botanically unrelated foods, as demonstrated for LTPs of maize and peach. A class of food allergens of well recognized clinical importance is that of seed storage 2S albumins. They have been identified in the most diffused edible seeds and nuts, such as mustard, sesame, Brazil nut, walnut and peanut. In particular, a strong correlation between IgE-binding to these proteins and food-induced anaphylaxis has been demonstrated for Brazil nut and sesame seeds.

Albumins↗
PubMed1999

Improved glycemic control and lipid profile and normalized fibrinolytic activity on a low-glycemic index diet in type 2 diabetic patients.

OBJECTIVE: To evaluate the effects of varying the glycemic index (GI) of carbohydrate-rich foods on metabolic control in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: In a randomized crossover study, 20 patients, 5 women and 15 men, were given preweighed diets with different GIs during two consecutive 24-day periods. Both diets were composed in accordance with dietary recommendations for people with diabetes. The macronutrient composition and type and amount of dietary fiber were identical. Differences in GI were achieved mainly by altering the structure of the starchy foods. RESULTS: Peripheral insulin sensitivity increased significantly and fasting plasma glucose decreased during both treatment periods. There was a significant difference in the changes of serum fructosamine concentrations between the diets (P < 0.05). The incremental area under the curve for both blood glucose and plasma insulin was approximately 30% lower after the low- than after the high-GI diet. LDL cholesterol was significantly lowered on both diets, with a significantly more pronounced reduction on the low-GI diet. Plasminogen activator inhibitor-1 activity was normalized on the low-GI diet, (-54%, P < 0.001), but remained unchanged on the high-GI diet. CONCLUSIONS: A diet characterized by low-GI starchy foods lowers the glucose and insulin responses throughout the day and improves the lipid profile and capacity for fibrinolysis, suggesting a therapeutic potential in diabetes.

Aged↗
PubMed1995

c-fos expression in the paraventricular nucleus of the hypothalamus following intracerebroventricular infusions of neuropeptide Y.

Intracerebroventricular (i.c.v.) infusions of neuropeptide Y (NPY) (2500 pmol) induced c-fos protein in the paraventricular nucleus (PVN) of intact male rats 60 min later. The greatest expression was observed in the dorsal (parvicellular) region of the PVN; there were intermediate levels in the lateral (magnocellular) and lowest ones in the medial (parvicellular) regions. Allowing rats to eat during the post-infusion interval did not modify this pattern of c-fos expression. Depriving rats of food for either 24 or 48 h did not induce recognisable expression of c-fos in the PVN, and allowing 24 h-deprived rats to eat also had no effect on PVN c-fos. Plasma insulin was increased by i.c.v. NPY, and raised still further in rats that were allowed to eat following NPY infusions. However, plasma glucose was not altered by either treatment. Food-deprived rats had low levels of insulin, but unaltered blood glucose, compared to controls. These results show that NPY can induce c-fos expression in both parvicellular and magnocellular areas of the PVN. The pattern of expression within the PVN seems to differ from that induced by other peptides, such as angiotensin II, vasopressin and corticotropin-releasing factor, suggesting that distinct populations of neurons are activated by different peptides within the complex structure of the PVN. Food deprivation does not induce c-fos expression within the PVN, though other studies have shown that NPY levels and release are both increased, so there is no simple relation between current energy state, blood levels of either glucose or insulin and c-fos expression within the PVN.

Animals↗
PubMed2002

[Food habits, physical activity and overweight among adolescents].

BACKGROUND: Overweight and obesity prevalence is increasing worldwide. Not only adults but also children and adolescents are involved. There are no recent data from French West Indies, where situation is believed to be worrying. Hence, the objective of the study was to provide information on the situation of adolescents, describing their nutritional status, food consumption and physical activity habits. METHODS: A sample of adolescents of both sexes, 14 to 15 years of age, was drawn among the 45 secondary schools of the Island. Of 993 adolescents drawn, 715 participated in the study which consisted in a questionnaire on their food and physical activity habits and anthropometric measurements. RESULTS: As a whole these adolescents displayed a greater growth rate than the WHO reference population. About 20% presented a body mass index (BMI) over the chosen thresholds for overweight and obesity. They were slightly more mature than the French Continental children (i. e. girls experienced menarche at 11.9 +/- 1.0 years of age versus 13 years in Metropolitan France). Their food habits were similar in structure and composition, to those of westernised countries, while retaining some features of the "Creole culture". Foods rich in animal fats and carbohydrates were prevailing. Girls ate less dairy products than boys (53% of the adolescent girls drank milk during breakfast against 64% of the boys). Almost every boy had a sport activity out of school, but girls were less often enrolled in sports. Sport activity decreased with age. There were no clear differences in physical activity levels between adolescents with high BMI or low BMI. CONCLUSIONS: There is an excess of overweight and obesity in this adolescent population. These conditions may have appeared soon during childhood and be hardly modified latter. Physical activity level would have a stronger impact on fatness during childhood than at adolescence. Hence, a special attention should be brought early to the nutritional status, food and physical activity habits of young children, given the risks to develop degenerative diseases when adults.

Adolescent↗
PubMed2005

Effects of intrauterine food restriction and long-term dietary supplementation with L-arginine on age-related changes in renal function and structure of rats.

We have previously demonstrated that restricting intrauterine food by 50% in 3-mo-old rats produced lower nephron numbers and early-onset hypertension, the latter being normalized by L-arginine administration. In 18-mo-old rats, such restriction increased glomerulosclerosis. In this study, we expanded our investigation, evaluating functional, morphologic, and immunohistochemical parameters in intrauterine-food-restricted 18-mo-old rats, either receiving L-arginine (RA18) or not (R18). Age-matched, non-food-restricted controls were assigned to similar groups with L-arginine (CA18) and without (C18). After weaning, L-arginine was given daily for 17 mo. No functional or morphologic changes were observed in C18 rats. The R18 rats developed early-onset hypertension, which persisted throughout the observation period, as well as significant proteinuria from 12 mo on. In RA18 rats, L-arginine decreased both blood pressure levels and proteinuria, and glomerular diameter was significantly smaller than in R18 rats (115.63 +/- 2.2 versus 134.8 +/- 1.0 mum, p < 0.05). However, in RA18 rats, glomerular filtration rate remained depressed. Although L-arginine prevented glomerulosclerosis (R18 = 14%, RA18 = 4%; p < 0.05), glomerular expression of fibronectin and desmin was still greater in RA18 rats than in controls. Our data show that, although L-arginine prevented hypertension and proteinuria, glomerular injury still occurred, suggesting that intrauterine food restriction may be one of the leading causes of impaired renal function in adult life.

Actins↗
PubMedDate not supplied

[Neuropharmacologic analysis of the process of developing extinctive inhibition in the lobectomized cat].

Pharmacological action on cholinergic and monoaminergic brain structures in the process of food-procuring reflex extinction was studied in intact and lobectomized cats. Growing stimulation of cholinergic structures of lobectomized animals caused consecutive behavioural changes similar to those appearing during development of active reaction of intact animals to cancellation of the reflex reinforcement. In both cases influences on monoaminergic systems produced analogous effects, but suppressing influence of haloperidol injection on food-procuring activity of lobectomized cats was significantly weakened. Conclusion is made that the development of active reaction of the animal to cancellation of food reinforcement is due to an increasing activation of brain cholinergic structures and consecutive activation of monoaminergic structures. Disturbance of extinction functions in lobectomized cats may be connected with disturbance of monoaminergic systems balance as a result of hyperactivity of dopaminergic structures.

Acetylcholine↗
PubMed2006

Incorporation of plant carbon into the soil animal food web of an arable system.

We used stable isotopes to examine the incorporation of plant carbon into the belowground food web of an agricultural system. Plots were established and planted with maize (Zea mays) in a rye field (Secale cereale) near Göttingen (northern Germany) in May 1999. In October 1999, April 2000, and October 2000, meso- and macrofauna and maize and rye litter were collected in each plot and analyzed for 13C and 15N content. 15N signatures suggested that the soil animal species analyzed span three trophic levels with the trophic position of species varying little in time. The species investigated formed a continuum from primary to secondary decomposers to predators. On average, predator species differed from primary and secondary decomposers by 3.9 sigma15N suggesting that they fed on a mixed diet of both decomposer groups. The combined analysis of 13C and 15N signatures allowed us to identify links between prey and consumer species. In October 1999, shortly after maize residues had been incorporated into the plots, maize-born carbon was present in each of the animal species investigated, including top predators. The incorporation of maize carbon into the belowground food web increased during the following 12 months but the concentration of maize-born carbon never exceeded 50% in any of the species. Furthermore, the ranks of the incorporation of maize-born carbon of the species changed little. The results suggest that the belowground food web relies heavily on carbon originating from plant residues from before the recent two growing seasons. In most species the amount of maize-born carbon increased continuously; however, in some species it decreased during winter, suggesting that these species switched to a diet based more on C3 plants during winter, or predominantly metabolized carbon incorporated during the last growing season. The study documents that the combined analysis of 13C and 15N signatures in soil invertebrate species, after replacement of C3 by C4 plants, is a powerful tool to better understand the structure of the belowground food web and the flux of carbon through it.

Agriculture↗
PubMed1998

Separation and recovery of food coloring dyes using aqueous biphasic extraction chromatographic resins.

Aqueous biphasic systems (ABS) and aqueous biphasic extraction chromatographic (ABEC) resins are currently under investigation for their utility in the removal of color from textile plant wastes. The structures of several widely used food colorings, suggest that these dyes would also be retained on the resins. In work currently in progress, we have begun to investigate the retention and resolution of several common food colorings including indigo carmine, amaranth, carminic acid. erythrosin B, tartrazine and quinoline yellow. The relationship between the uptake of these dyes on ABEC resins in terms of the binding strengths and capacities of the resins and their partitioning behavior in ABS is illustrated. Some possible theoretical and practical approaches to the prediction of the partitioning and retention behavior is discussed.

Chromatography↗
PubMed2004

Population effects of growth hormone transgenic coho salmon depend on food availability and genotype by environment interactions.

Environmental risk assessment of genetically modified organisms requires determination of their fitness and invasiveness relative to conspecifics and other ecosystem members. Cultured growth hormone transgenic coho salmon (Oncorhynchus kisutch) have enhanced feeding capacity and growth, which can result in large enhancements in body size (>7-fold) relative to nontransgenic salmon, but in nature, the ability to compete for available food is a key factor determining survival fitness and invasiveness of a genotype. When transgenic and nontransgenic salmon were cohabitated and competed for different levels of food, transgenic salmon consistently outgrew nontransgenic fish and could affect the growth of nontransgenic cohorts except when food availability was high. When food abundance was low, dominant individuals emerged, invariably transgenic, that directed strong agonistic and cannibalistic behavior to cohorts and dominated the acquisition of limited food resources. When food availability was low, all groups containing transgenic salmon experienced population crashes or complete extinctions, whereas groups containing only nontransgenic salmon had good (72.0 +/- 4.3% SE) survival, and their population biomass continued to increase. Thus, effects of growth hormone transgenic salmon on experimental populations were primarily mediated by an interaction between food availability and population structure. These data, while indicative of forces which may act on natural populations, also underscore the importance of genotype by environment interactions in influencing risk assessment data for genetically modified organisms and suggest that, for species such as salmon which are derived from large complex ecosystems, considerable caution is warranted in applying data from individual studies.

Animals↗
PubMed2006

Feeding by larvae of intertidal invertebrates: assessing their position in pelagic food webs.

One of the leading determinants of the structure and dynamics of marine populations is the rate of arrival of new individuals to local sites. While physical transport processes play major roles in delivering larvae to the shore, these processes become most important after larvae have survived the perils of life in the plankton, where they usually suffer great mortality. The lack of information regarding larval feeding makes it difficult to assess the effects of food supply on larval survival, or the role larvae may play in nearshore food webs. Here, we examine the spectrum of food sizes and food types consumed by the larvae of two intertidal barnacle species and of the predatory gastropod Concholepas concholepas. We conducted replicated experiments in which larvae were exposed to the food size spectrum (phytoplankton, microprotozoan and autotrophic picoplankton) found in nearshore waters in central Chile. Results show that barnacle nauplii and gastropod veligers are omnivorous grazers, incorporating significant fractions of heterotrophs in their diets. In accordance with their feeding mechanisms and body size, barnacle nauplii were able to feed on autotrophic picoplankton (<5 microm) and did not consume the largest phytoplankton cells, which made the bulk of phytoplankton biomass in spring-summer blooms. Balanoid nauplii exhibited higher ingestion rates than the smaller-bodied chthamaloid larvae. Newly hatched C. concholepas larvae also consumed picoplankton cells, while competent larvae of this species ingested mostly the largest phytoplankton cells and heterotrophic protozoans. Results suggest that persistent changes in the structure of pelagic food webs can have important effects on the species-specific food availability for invertebrate larvae, which can result in large-scale differences in recruitment rates of a given species, and in the relative recruitment success of the different species that make up benthic communities.

Animals↗
PubMed1996

Peripherally administered calcitonin gene-related peptide decreases food intake in mice.

Previously, calcitonin gene-related peptide (CGRP) decreased food intake when administered ICV but not when administered peripherally to rats. Amylin, which has a close structural homology to CGRP, reduced food intake administered IP at concentrations higher than those previously tested for CGRP. We examined the effects of higher doses of IP-administered CGRP on food intake. CGRP reduced food intake from 25 to 200 micrograms/kg in mice. CGRP did not reduce water intake and was not aversive in a two-bottle test. Using a lever press, CGRP was more effective at reducing milk consumption in prefed than in nonprefed mice. The effect of CGRP on food intake was not antagonized by the cholecystokinin A receptor antagonist, L364,718. These studies suggest a role for CGRP as a satiating factor.

Analysis of Variance↗
PubMed2000

Food handlers and foodborne diseases: knowledge, attitudes, and reported behavior in Italy.

The purpose of this study was to evaluate knowledge, attitudes, and behavior concerning foodborne diseases and food safety issues among food handlers in Italy. Face-to-face interviews were conducted within a random sample using a structured questionnaire. Of the 411 food handlers responding, 48.7% knew the main foodborne pathogens (Salmonella spp., Staphylococcus aureus, Vibrio cholerae or other Vibrio spp., Clostridium botulinum, hepatitis A virus), and this knowledge was significantly greater among those with a higher education level, in practice from a longer period of time, and who had attended education courses (P < 0.05). A vast majority (90.4%) correctly indicated those foods classified as common vehicles for foodborne diseases, and only 7.1% of food handlers were able to name five different food vehicles, each of which transmit one of the five pathogens. The proportion of those who were able to specify a food vehicle that transmitted hepatitis A virus was significantly higher for those with a higher educational level and with a longer food-handling activity. A positive attitude toward foodborne diseases control and preventive measures was reported by the great majority of food handlers, and it was more likely achieved by those who had attended education courses. This attitude was not supported by some of the self-reported safe practices observed for hygienic principles, because only 20.8% used gloves when touching unwrapped raw food, and predictors of their use were educational level and attending education courses. Results strongly emphasize the need for educational programs for improving knowledge and control foodborne diseases.

Adolescent↗
PubMedDate not supplied

[The organization of instrumental food-procuring movements in rats].

The roles of the lateral hypothalamus, basolateral nucleus of the amygdalar complex, the second field of the frontal cortex, and ventromedial thalamic nucleus in organization of the fast ballistic food-procuring movements were studied in albino rats. Sequences of uni- and bilateral destruction of the brain structures were assessed by photorecording. Movement-related neuronal activity in these structures was recorded in freely moving animals. A specific involvement of each of the above listed structures in organization of food-procuring movements was shown. The lateral hypothalamus seems to participate in initiation of the motor program and its efficient realization, the basolateral amygdala appears to produce activatory, training, and stabilizing effects. The second field of the motor cortex leads in movement acquisition (i.e., in memorizing) and decision making about triggering the program. The idea about the relay role of the thalamic motor nucleus is supplemented by understanding of its more complex integrative function.

Amygdala↗