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PubMed1990

Food-storing birds: adaptive specialization in brain and behaviour?

Among the passerine birds, species that store food have an enlarged hippocampal region (dorso-medial cortex), relative to brain and body size, when compared with the non-storers. The volume of one of the major afferent-efferent pathways (the septo-hippocampal pathway) is also greater in food storing species. This specialization of brain structure is discussed in relation to behavioural studies in which the spatial memory of storing and non-storing species has been compared.

Adaptation, Physiological↗

PubMed1976

Ultrastructure of intraerythrocytic Babesia microti with emphasis on the feeding mechanism.

Babesia microti is a highly polymorphic organism. To unravel its fine structure and the function of organelles it was necessary to resort often to serial sections. A single plasma membrane covers the organism. In trophozoites approaching reproduction, segments of double membranes can be found below the plasma membrane. In electron micrographs of poor resolution these segments of double membranes look like pieces of thick membranes and they were often thought to be a thick 2nd membrane. Before the segments of double membranes appear 2 other organelles are formed in older trophozoites: micronemes and rhoptries. There are indications that these structures originate from vesicles of the Golgi apparatus. Large dense bodies of the same structure as the host cytoplasm are not food vacuoles but merely invaginations of host cytoplasm, as found in serial sections and in organisms removed from the host cell. Feeding in Babesia seems to take place by a special organelle composed of tightly coiled double membranes located partly inside and partly outside the parasite. It is assumed that extracellular digestion of host cytoplasm take place through this organelle. The nucleus remains undifferentiated throughout the whole intraerythrocytic stage. It becomes irregular, loboid, but does not divide and remains a single body until the late stage of reproduction when only a small portion, a bud, extends into the forming merozoite.

Animals↗

PubMed1999

Gene sequence and properties of an s-triazine ring-cleavage enzyme from Pseudomonas sp. strain NRRLB-12227.

Pesticides based on the s-triazine ring structure are widely used in cultivation of food crops. Cleavage of the s-triazine ring is an important step in the mineralization of s-triazine compounds and hence in their complete removal from the environment. Cyanuric acid amidohydrolase cleaves cyanuric acid (2,4,6-trihydroxy-s-triazine), which yields carbon dioxide and biuret; the biuret is subject to further metabolism, which yields CO(2) and ammonia. The trzD gene encoding cyanuric acid amidohydrolase was cloned into pMMB277 from Pseudomonas sp. strain NRRLB-12227, a strain that is capable of utilizing s-triazines as nitrogen sources. Hydrolysis of cyanuric acid was detected in crude extracts of Escherichia coli containing the cloned gene by monitoring the disappearance of cyanuric acid and the appearance of biuret by high-performance liquid chromatography (HPLC). DEAE and hydrophobic interaction HPLC were used to purify cyanuric acid amidohydrolase to homogeneity, and a spectrophotometric assay for the purified enzyme was developed. The purified enzyme had an apparent K(m) of 0.05 mM for cyanuric acid at pH 8.0. The enzyme did not cleave any other s-triazine or hydroxypyrimidine compound, although barbituric acid (2,4, 6-trihydroxypyrimidine) was found to be a strong competitive inhibitor. Neither the nucleotide sequence of trzD nor the amino acid sequence of the gene product exhibited a significant level of similarity to any known gene or protein.

Amidohydrolases↗

PubMed2006

Bats: important reservoir hosts of emerging viruses.

Bats (order Chiroptera, suborders Megachiroptera ["flying foxes"] and Microchiroptera) are abundant, diverse, and geographically widespread. These mammals provide us with resources, but their importance is minimized and many of their populations and species are at risk, even threatened or endangered. Some of their characteristics (food choices, colonial or solitary nature, population structure, ability to fly, seasonal migration and daily movement patterns, torpor and hibernation, life span, roosting behaviors, ability to echolocate, virus susceptibility) make them exquisitely suitable hosts of viruses and other disease agents. Bats of certain species are well recognized as being capable of transmitting rabies virus, but recent observations of outbreaks and epidemics of newly recognized human and livestock diseases caused by viruses transmitted by various megachiropteran and microchiropteran bats have drawn attention anew to these remarkable mammals. This paper summarizes information regarding chiropteran characteristics and information regarding 66 viruses that have been isolated from bats. From these summaries, it is clear that we do not know enough about bat biology; we are doing too little in terms of bat conservation; and there remain a multitude of questions regarding the role of bats in disease emergence.

Animals↗

PubMed2003

Characteristics and immunobiology of grass pollen allergens.

Grass pollens are one of the most important airborne allergen sources worldwide. About 20 species from five subfamilies are considered to be the most frequent causes of grass pollen allergy, and the allergenic relationships among them closely follow their phylogenetic relationships. The allergic immune response to pollen of several grass species has been studied extensively over more than three decades. Eleven groups of allergens have been identified and described, in most cases from more than one species. The allergens range from 6 to 60 kD in apparent molecular weight and display a variety of physicochemical properties and structures. The most complete set of allergens has so far been isolated and cloned from Phleum pratense (timothy grass) pollen. Based on the prevalence of IgE antibody recognition among grass pollen-sensitized individuals, several allergens qualify as major, but members of two groups, groups 1 and 5, have been shown to dominate the immune response to grass pollen extract. Isoform variation has been detected in members of several of the allergen groups, which in some cases can be linked to observed genetic differences. N-linked glycosylation occurs in members of at least three groups. Carbohydrate- reactive IgE antibodies have been attributed to grass pollen sensitization and found to cross-react with glycan structures from other allergen sources, particularly vegetable foods. Another cause of extensive cross-reactivity are the group 12 allergens (profilins), which belong to a family of proteins highly conserved throughout the plant kingdom and present in all tissues. Members of eight allergen groups have been cloned and expressed as recombinant proteins capable of specific IgE binding. This development now allows diagnostic dissection of the immune response to grass pollen with potential benefits for specific immunotherapy.

Allergens↗

PubMed2004

Advanced glycation end products in clinical nephrology.

As a result of oxidative and carbonyl stress, advanced glycation end products (AGEs) are involved in the pathogenesis of severe and frequent diseases and their fatal vascular/cardiovascular complications, i.e. diabetes mellitus and its complications (nephropathy, angiopathy, neuropathy and retinopathy, renal failure and uremic and dialysis-associated complications), atherosclerosis and dialysis-related amyloidosis, neurodegenerative diseases, and rheumatoid arthritis. They are formed via non-enzymatic glycation which is specifically enhanced through the presence of oxidative and carbonyl stress, and their ability to form glycoxidation products in peptide and protein structures finally modulating or inducing biological reactivity. Food can be another source of AGEs; however, high serum AGEs in hemodialysis patients might reflect nutritional status better. Several methods of renal replacement therapy have been studied in connection with the AGE removal, but unfortunately the possibilities are still unsatisfactory even if high flux dialysis, hemofiltration, or hemodiafiltration give better results than conventional low flux dialysis. AGEs are currently being studied in the patients on peritoneal dialysis as their precursors can be formed in the dialysis fluid. AGEs can cause damage to the peritoneum and so a loss of ultrafiltration capacity. Many compounds give promising results in AGE inhibition (inhibition of formation of AGEs, inhibition of their action or degradation of AGEs), are tested for these properties, and eventually undergo clinical studies (e.g. aminoguanidine, OPB-9195, pyridoxamine, antioxidants, N-phenacylthiazolium bromide, antihypertensive drugs, angiotensin-converting enzyme inhibitors and angiotensin II receptor-1 antagonists).

Amyloidosis↗

PubMed2005

A wheat xylanase inhibitor gene, Xip-I, but not Taxi-I, is significantly induced by biotic and abiotic signals that trigger plant defense.

XIP-I and TAXI-I are wheat (Triticum aestivum L) grain proteins that inhibit microbial xylanases used in food processing. Although their biochemical properties and structural features were established recently, very little is known about their expression and their family members in wheat plants. To clarify the role of these xylanase inhibitor proteins in plant defense, we examined the expression of the XIP-type genes in response to a variety of biotic and abiotic signals. Although Xip-I was not expressed in flowering spikelets inoculated with Fusarium graminearum, transcription of Xip-I was greatly enhanced in Erysiphe graminis-infected leaves. Thus, unlike Taxi-I, Xip-I is pathogen-inducible, and unlike Taxi-III and Taxi-IV, its expression depends on the type of the pathogen and/or infected tissue. Xip-I was expressed when the leaves were wounded, and its expression was significantly elevated by treatment with methyl jasmonate (MeJA). The different expression profiles of XIP- and TAXI-type genes suggest distinct roles in plant defense.

Amino Acid Sequence↗

PubMed1997

Dietary flavonoid and cancer prevention: evidence and potential mechanism.

Dietary flavonoids represent a family of polyphenol compounds found in common food items derived from plants. Depending on structural features, flavonoids can be further subdivided into flavones, flavonols, isoflavones, flavanes, and flavanols. The biological activities of flavonoids are structure dependent and epidemiological studies support their role in human cancer prevention. Several flavonoids inhibit cancer development in animal models of chemical and UV carcinogenesis. However, at high dose some flavonoids themselves may also increase cancer incidence. Although flavonoids have been shown to inhibit cancer cell growth in vitro, the ability of flavonoids to limit cancer progression is limited in animal studies. A potential application is the possible synergisticaction of flavonoids with chemotherapy agents. Molecularly, flavonoids have antioxidant properties and can further enhance the antioxidant protein activities in cells and in animals. Isoflavones and some other flavonoids have weak affinity for the estrogen receptor. Neonatal exposure of animals to isoflavonoids affects the development of reproductive organs, an observation that opens the possibility of using isoflavonoids in the prevention of cancers of the reproductive system. Some growth-inhibiting flavonoids also bind to the low-affinity type II estrogen binding sites, but the biochemical identity of type II sites is unknown.

Animals↗

PubMedDate not supplied

Growth and maturation of children with insulin-dependent diabetes mellitus.

The purpose of this paper is to define criteria used for classifying patients into varying degrees of diabetic control and to verify that children with diabetes maintained in higher degrees of metabolic control do not have delayed growth and maturation. Growth records of 252 children with insulin-dependent diabetes who have been under continuous observation in our clinic at three- to five-month intervals for at least three years and up to 16 years have been individually reviewed and analyzed. All children received two daily injections of a mixture of two parts of an intermediate to one part of regular insulin and were instructed to eat structured meals of high-quality selected foods. An over-all rating for diabetic control based primarily on the frequency and degree of glycosuria was made for the time period between clinic visits. The over-all diabetic control rating and the size of the subgroups were "good"--20 per cent, "fair to good"--64 per cent, and "fair"--16 per cent. All children maintained in "good" and "fair to good" control (84 per cent), grew and matured at a normal rate regardless of the age at onset or duration of diabetes. All children in lower degrees of control coming under care for greater than 24 months after diagnosis had accelerated growth during the early months after attaining a higher degree of control.

Adolescent↗

PubMed2005

Cases of swallow syncope induced by the activation of mechanorecepters in the lower esophagus.

Swallowing is a rare cause of neurally mediated syncope. The mechanism of swallow syncope that contributes to hypotension, bradycardia, or to both is complex. A 59-year-old man had experienced a recurrent loss of consciousness during swallowing of carbonated beverages or sticky foods. Another 59-year-old man had complained of intermittent syncope just after eating foods. These two patients had no significant structural or functional abnormalities in the esophagus or heart. Both cases showed bradycardia when the lower esophagus was stretched by balloon inflation. The activation of mechanoreceptors in the lower esophagus can be regarded as an initiating factor of these cardioinhibitions. The patients were treated with permanent pacemaker implantation and instructed to change eating habits, respectively.

Bradycardia↗

PubMedDate not supplied

Influence of occlusal scheme on the pressure distribution under a complete denture.

PURPOSE: The purpose of this study was to estimate which occlusion offers the best conditions of pressure distribution on the supporting structure under a complete denture when crushing food. MATERIALS AND METHODS: Simulated maxillary and mandibular complete dentures with three different posterior occlusal schemes--fully balanced occlusion, lingualized occlusion, and monoplane occlusion--were fabricated. Eight pressure transducers were placed in the basal surface of a mandibular denture. The pressure distribution on the mandibular edentulous mouth model with 1.5-mm-thick artificial tissue under a complete denture was recorded when crushing three different foods: soft food (kamaboko), peanuts, and carrot. The mean pressure values at each measurement point and the force required for each test were compared using one-way analysis of variance with P < or = 0.05 representing statistical significance. RESULTS: The required force for crushing a soft food or carrot in the left molar region in monoplane occlusion was significantly larger than that required in fully balanced occlusion or lingualized occlusion. In crushing soft food, fully balanced occlusion showed significantly higher pressure values on the working side than in monoplane occlusion or lingualized occlusion. In crushing the carrot, the pressure values in fully balanced occlusion and in lingualized occlusion were significantly lower than those in monoplane occlusion. CONCLUSION: These results demonstrate that with fully balanced occlusion and lingualized occlusion a large occlusal force is not needed for crushing hard food, and the stress to the supporting tissues is smaller than with monoplane occlusion.

Alveolar Process↗

PubMed1992

Metabolic responses to starch in bread containing intact kernels versus milled flour.

In the present study, the potential of including intact kernels from different cereals was evaluated as a means of developing bread with 'lente' characteristics. Postprandial glucose and insulin responses to bread products were studied in healthy subjects. In parallel, the in-vitro enzymic starch availability was investigated. Also studied were the contents of in-vitro indigestible starch. Coarse bread (CB) products composed of 80% pre-boiled kernels from wheat, rye, oats or barley and 20% white wheat flour were baked. In the case of barley, two forms for pre-treatments was used, boiling and scalding. A bread with 80% wholemeal barley flour and 20% white wheat flour (WMB) was also included and a white wheat bread (WWB) was used as reference. The glycaemic and insulinaemic indexes (GI and II, respectively) were calculated from the 95 and 120 min incremental blood glucose and insulin areas. The GIs were significantly lower with CB from wheat, rye and barley than with WWB. In contrast, the GIs with CB from oats and WMB from barley were similar to that with WWB. The GIs and IIs were generally closely correlated. However, the II with CB from oats was significantly lower than with WWB despite similar GI. The GIs, and in particular IIs, were closely correlated with the hydrolysis rate index (HI) obtained in vitro, and this procedure can be recommended as a tool for ranking of starchy food. It is concluded that the botanical structure is an important determinant of the enzymic availability and hence of the metabolic responses. The in-vitro indigestible starch content was highest in CB from barley (1.2% dry weight basis) and lowest in CB from oats (0.5%).

Adult↗

PubMed2004

[Nutrient and water cycling in red soils with different planting system and their management].

Based on the data of long term located experiment, this paper studied the characteristics of nutrient and water cycling and balance and of energy flow in upland red soils with different planting system. The results showed that in red soil areas, the rainfall from March to June accounted for 60% of the whole year, which induced frequent seasonal drought and severe water and soil loss. The application of N, P and K on upland red soil was overabundant and unbalanced, which induced a reduced ratio of input and output. Optimized planting mode could increase the water and light utilization efficiency, decrease the frequency and degree of occurred drought, and increase the nutrient recycling rate. The main measures for rationally developing and utilizing red soil should be establishing compound agro-ecosystem model of planting and feeding, saving irrigation water, increasing mulch, cover-cultivating crops and forests, increasing the proportion of organic fertilizer, realizing rational and balanced fertilization, further optimizing planting structure, regulating energy input structure, and adopting multilevel-technologies of food chain utilization.

China↗

PubMed1991

Synthesis of (+/-)-N-2-methylpropyl-N-1'-methylacetonyl-nitrosamine.

N-2-methylpropyl-N-1-methylacetonyl-nitrosamine (NMAMPA), first isolated from moldy and normal foods, was synthesized by chemical means. The structure and molecular weight of the synthetic NMAMPA were elucidated by spectrometry. A combination of spectral and chromatographic data indicated that the synthetic NMAMPA is identical to that obtained naturally. Synthetic NMAMPA is a racemic modification, and a carcinogen which can induce esophageal and forestomach cancer in rats.

Carcinogens↗

PubMedDate not supplied

[A method of calculating the average food and energy requirements of the population].

The paper presents the methods for counting mean per head food and energy requirements of the population, based on the standards of physiological needs of varying groups of the population in food products and energy, and on demographic structure of the population with due account for sex, age, work and living conditions, climato-geographical regions and other factors.

Adolescent↗

PubMed1998

Physical and chemical transformations of cereal food during oral digestion in human subjects.

Chemical and physical transformations of solid food begin in the mouth, but the oral phase of digestion has rarely been studied. In the present study, twelve healthy volunteers masticated mouthfuls of either bread or spaghetti for a physiologically-determined time, and the levels of particle degradation and starch digestion before swallowing were compared for each food. The amounts of saliva moistening bread and spaghetti before swallowing were, respectively, 220 (SEM 12) v. 39 (SEM 6) g/kg fresh matter. Particle size reduction also differed since bread particles were highly degraded, showing a loss of structure, whereas spaghetti retained its physical structure, with rough and incomplete reduction of particle size. Starch hydrolysis was twice as high for bread as for spaghetti, mainly because of the release of high-molecular-mass alpha-glucans. The production of oligosaccharides was similar after mastication of the two foods, respectively 125 (SEM 8) and 92 (SEM 7) g/kg total starch. Starch hydrolysis, which clearly began in the mouth, depended on the initial structure of the food, as in the breakdown of solid food. These significant physical and chemical degradations of solid foods during oral digestion may influence the entire digestive process.

Adult↗

PubMed2006

Age-related expression of alpha-gustducin in the rat larynx.

OBJECTIVES: The age-related changes in distribution of alpha-gustducin-immunoreactive structures in the larynx of Sprague-Dawley rats were studied. METHODS: For this purpose, tissues obtained from 12 male rats ranging in age from 5 to 21 weeks were compared with respect to the distribution and morphology of laryngeal taste buds immunoreactive for alpha-gustducin, the alpha-subunit of a taste cell-specific G protein. RESULTS: Three different morphological types of alpha-gustducin-immunoreactive structures were seen: typical gemmal forms, clusters composed of 2 or 3 cells, and isolated immunoreactive cells not associated with taste buds. alpha-Gustducin-immunoreactive structures were most abundant in the epiglottis in all age groups. alpha-Gustducin-immunoreactive cells in rats seem to be located along the lateral food channels, in which they may come in contact with food. The total number of these alpha-gustducin-immunoreactive structures did not show any age-related changes, but the percentage of solitary immunoreactive cells in 5-week-old rats was significantly larger than the percentages in 8-, 14-, and 21-week-old animals. CONCLUSIONS: Solitary alpha-gustducin-immunoreactive cells, which are abundant in 5-week-old rats but are found in fewer numbers along the base of the epiglottis in mature rats, may be nociceptic in function, whereas the chemosensory clusters or buds that contain alpha-gustducin-positive cells and are distributed along the lateral food channels on the pharyngeal side of the larynx may have a role in gustatory reception.

Aging↗

PubMed1998

Amino-reductones. Formation mechanisms and structural characteristics.

Various types of amino-reductones are known to be involved in process-induced chemical changes in foods. Since most amino-reductones, especially enaminol compounds are unstable reaction intermediates and are difficult to isolate, their structural characteristics are still unclear. In order to obtain more precise structural information about amino-reductones, the structures of the enaminol form of fructoseglysine (D-fructoseglycine = FG) and scorbamic acid (L-scorbamic acid = SCA), a relatively stable cyclic enaminol compound were examined by the use of a semi-empirical molecular orbital method. Optimized structures, heat of formations and charge distributions of various enol forms of FG were obtained. Heat of formations of the non-dissociated, mono-anion, and di-anion forms of FG were estimated to be about -302, -347 and -308 kcal/mol, respectively. Optimized structures of non-dissociated, anion, and dipolar ion forms of SCA were also obtained and their heat of formations were estimated to be about -197, -204 and -248 kcal/mol, respectively. The nitrogen atom of the enaminol group in the SCA molecule was found to be positively charged.

Ascorbic Acid↗