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Results for “nutritional environment”

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At least 91 records · Page 5Linked to original sources
PubMed2006

Expression and mapping of lubricin in canine flexor tendon.

Matrix composition and the biomechanical environment are intimately interdependent in most connective tissues. Lubricin has many distinct biological functions, including lubrication, antiadhesion, and cytoprotection in cartilage, tendons, and other tissues. This study investigated the distribution of lubricin in the canine flexor digitorum profundus (FDP) tendon by immunohistochemistry. Lubricin was found both on the tendon surface and at the interface of collagen fiber bundles within the tendon, where the cells are subjected to shear force in addition to tension and compression. The expression of lubricin in regions of the canine flexor tendon that differ in mechanical or nutritional environment was also investigated using RT-PCR. Six N-terminal splicing variants were identified from six distinct anatomical regions of flexor tendon. The variants with larger sizes were noted in regions subjected to significant shear and compressive forces. Lubricin is ubiquitous in the FDP tendon, with variations in distribution and splicing that appear to correspond to discrete anatomic locations that differ by mechanical or nutritional environment.

Animals↗
PubMed2006

Evolving resistance to obesity in an insect.

Failure to adapt to a changing nutritional environment comes at a cost, as evidenced by the modern human obesity crisis. Consumption of energy-rich diets can lead to obesity and is associated with deleterious consequences not only in humans but also in many other animals, including insects. The question thus arises whether animals restricted over multiple generations to high-energy diets can evolve mechanisms to limit the deposition of adverse levels of body fat. We show that Plutella xylostella caterpillars reared for multiple generations on carbohydrate-rich foods (either a chemically defined artificial diet or a high-starch Arabidopsis mutant) progressively developed the ability to eat excess carbohydrate without laying it down as fat, providing strong evidence that excess fat storage has a fitness cost. In contrast, caterpillars reared in carbohydrate-scarce environments (a chemically defined artificial diet or a low-starch Arabidopsis mutant) had a greater propensity to store ingested carbohydrate as fat. Additionally, insects reared on the low-starch Arabidopsis mutant evolved a preference for laying their eggs on this plant, whereas those selected on the high-starch Arabidopsis mutant showed no preference. Our results provide an experimental example of metabolic adaptation in the face of changes in the nutritional environment and suggest that changes in plant macronutrient profiles may promote host-associated population divergence.

Adipose Tissue↗
PubMed2006

Feed efficiency of rainbow trout can be improved through selection: different genetic potential on alternative diets.

To assess the genetic potential for selection of increased feed efficiency in rainbow trout (Oncorhynchus mykiss), we estimated the heritabilities and correlations for BW, daily weight gain (DG), and daily feed intake (DFI). Body weight was recorded 5 times, and DG and DFI 3 times during a feeding trial lasting 22 mo. To test the hypothesis that phenotypic and genetic parameters were influenced by a nutritional environment, fish were fed either a modern normal protein diet (NP, 40 to 45% protein and 30 to 33% lipid) or an alternative high protein diet (HP, 50 to 56% protein, 20 to 24% lipid) in a split-family design. Results showed that there were no large differences in heritabilities between the diets. Average heritability for DFI over both diets and different fish ages was low (average h2 = 0.10), indicating that modest genetic changes in response to selection can be obtained. Average heritabilities for BW and DG over both diets and different fish ages were 0.28 and 0.33, respectively. The NP diet enabled fish to express a wide range of BW, as shown by the increased coefficients of phenotypic variation for BW. Fish fed the HP diet showed increased phenotypic variation for DFI in > 750-g fish. On the NP diet, genetic correlations of DFI with DG and BW were very strong for 750- to 2,000-g fish. In contrast, on the HP diet, the respective correlations were moderate to low, revealing more genetic potential to change growth and feed intake simultaneously in opposite directions. An analysis of the predicted selection responses showed that selection solely for high DG improved feed efficiency as a correlated genetic response. Simultaneous selection for high DG and reduced DFI, in turn, may increase genetic gain in feed efficiency by a factor of 1.2 compared with selection solely for DG. However, variation for growth and feed intake and the relationships between these traits were different in different nutritional environments, leading to divergent genetic responses on the alternative diets.

Animal Feed↗
PubMed1999

[Kashin-Beck disease in China: osteochondrodysplasia related to nutrition and environment].

Kashin-Beck disease is a endemic juvenile osteochondrodysplasy, whose association with selenium deficiency and/or mycotoxin toxicity has been corroborated by epidemiological studies in China, including Tibet. Iodine deficiency appears to be a new etiological factor. Together with the geographical and epidemiological exploration of the disease, scientific multidisciplinary investigations (clinics, radiological imaging, histology, environmental and molecular biology) should afford to understand the cause of the disease before it disappears as a consequence of the evolution of the Chinese Society, including in Tibet.

Adult↗
PubMed1975

Induction of squamous metaplasia (vitamin A deficiency) and hypersecretory activity in tracheal organ cultures.

Maintenance of rat tracheal organ cultures in various nutritional environments was studied. In Waymouth's 752/1 defined, vitamin A-free medium the mucociliary epithelium, at the site of the original mucosa, changed to a highly active keratinizing squamous epithelium. Epithelial cells that migrated from the original mucosa and covered the underside of the tracheal explants developed into keratinizing squamous epithelium with in a few days. These transitions were accompanied by high rates of DNA synthesis as revealed by 3H-thymidine incorporation into the explants. Addition of 10 per cent horse serum to the Waymouth's medium completely inhibited squanous metaplasia. In this medium, the actively secreting mucociliary epithelium of the original mucosa slowly became quiescent, and the undergrowth epithelium usually remained undifferentiated. These explants maintained a lower level of DNA synthesis. When vitamin A (all trans retinol) was added to the serum-supplemented medium, 0.2 and 2.0 mug. per ml. induced hypersecretory activity in the original mucosa. Addition of 2.0 mug. per ml. also stimulated cellular hyperplasia and mitoses. A concentration of 20 mug. of vitamin A per milliliter of medium was toxic. It is concluded that a spectrum of epithelial cell types normally found in the tracheal mucosa in vivo can be induced and maintained in tracheal organ cultures in vitro by selection of the appropriate nutritional environment.

Animals↗
PubMed2003

Regulated mRNA stability of the Cdk inhibitor Rum1 links nutrient status to cell cycle progression.

BACKGROUND: The survival of a cell depends on continuous sensing of the nutritional environment and appropriate coordination of the cell cycle. The fission yeast Schizosaccharomyces pombe is an excellent model system in which to study these processes. In the presence of nutrients, fission yeast cells grow and divide, spending most of their time in G2; when nutrients are limiting, they are promoted into mitosis and arrest the cell cycle in G1. The molecular mechanisms underlying this response are currently unknown. RESULTS: Here, we show that expression of the fission yeast Cdk inhibitor Rum1, a key regulator of Cdc2/cyclin B in G1, is subject to regulated mRNA stability in response to nutrient deprivation. In complete minimal medium, rum1 mRNAs are very unstable. Following nitrogen starvation, rum1 mRNAs are rapidly stabilized, allowing the accumulation of Rum1 protein to delay the G1 phase of the subsequent cell cycle. Instability of rum1 mRNAs in complete minimal medium depends on the presence of AU-rich elements in the 3'UTR. We also show that lack of this mechanism has consequences in the mitotic cell cycle, in meiosis, and in the control of ploidy. CONCLUSION: We propose that mRNA stability is an important mechanism to fine tune the expression of the rum1 gene, in order to allow the production of appropriate levels of Rum1 protein in response to changes in the nutritional environment.

Base Sequence↗
PubMed1978

How mind, body, and environment influence nutrition in the elderly.

Eating habits, food preferences, and attitudes affecting nutrition in the elderly are the result of the interaction of numerous interpersonal and intrapersonal forces. The physiologic changes that accompany aging must be understood by the clinician and accepted by the elderly person. Social stress and other environmental factors can adversely affect nutritional status.

Aged↗
PubMed2003

Trading nutrition for education: nutritional status and the sale of snack foods in an eastern Kentucky school.

Overweight and poor nutrition of children in the United States are becoming issues of increasing concern for public health. Dietary patterns of U.S. children indicate they are consuming too few fruits and vegetables and too many foods high in fat and sugar. Contributing to this pattern of food consumption is snacking, which is reported to be on the increase among adults and children alike. One place where snacking is under increased scrutiny, and where it is being increasingly criticized, is in U.S. schools, where snack foods are often sold to supplement inadequate budgets. This article takes a biocultural approach to understanding the nutritional status of elementary school children in a rural community in eastern Kentucky. It pays particular attention to the ways in which the school's nutrition environment shapes overweight and nutritional status for many of the children, focusing on the sale of snack foods and the reasons behind the principal's decision to sell snack foods in the school.

Anthropology, Cultural↗
PubMed1980

Studies on new aminoglycoside antibiotics, istamycins, from an actinomycete isolated from a marine environment. III. Nutritional effects on istamycin production and additional chemical and biological properties of istamycins.

Streptomyces tenjimariensis SS-939 produced istamycins in a medium containing starch as the carbon source and soy bean meal as the nitrogen source. Istamycin production decreased substantially when starch was substituted with mono- or di- saccharides such as glucose, glycerol and maltose. A marked decrease of istamycin production was also observed when a rapidly used nitrogen source such as yeast extract, peptone or casamino acid was employed instead of soy bean meal. Addition of palmitate at a concentration of 0.2% doubled istamycin production. Istamycins A and B were found to be as active as fortimicin A and sporaricin A against Gram-positive and Gram-negative bacteria including aminoglycoside-resistant strains.

Aminoglycosides↗
PubMed1979

['Our future selves'. Comments on "Human services and delivery systems'].

A description is given of the recommended research topics on Human Services and Delivery Systems for the Aging. Fifteen different fields of research attention are described. It is stated that there is a lack of a frame of reference for the different attention fields. This frame of reference is necessary for a more systematic approach towards the age specific problems and the age specific services, needed to solve those problems. The systematic approach can be found in a three-dimensional scheme in which the fifteen attention fields have their logical place. The recommanded research topics have to be assessed in this frame: 1. Socio-cultural aspects. Culture, religion, ethics, communication, education, recreation, civic participation. 2. Socio-economic aspects. Economic support, employment, legal services, commerce. 3. Physical environment. Physical Environment, nutrition, transportation. 4. Human environment. This aspect is not mentioned in the report. 5. Psychological aspects. 6. Physical aspects. These aspects are not explicitly mentioned in the report, but implicitly in the chapter about Health. Some of the recommendations are also relevant for the situation in the Netherlands. The recommended research on the health care system is critisized, because the items are too complex. For the Netherlands it is more worthwhile to do fundamental research on the age-specific vulnerability in relation to social, psychological and physical aspects. The results of that research can be used for a reconstruction of the whole health care system for the aged.

Aged↗
PubMed2006

Genetic interactions with diet influence the risk of cardiovascular disease.

Single-nucleotide polymorphisms are an integral component of the evolutionary process that over millennia have resulted from the interaction between the environment and the human genome. Relatively recent changes in diet have upset this interaction with respect to the nutritional environment, but nutritional science is beginning to better understand the interaction between genes and diet, with the resulting potential to influence cardiovascular disease risk by dietary modification. Single-nucleotide polymorphisms in several genes have been linked to differential effects in terms of lipid metabolism; however, even a simple model of benefit and risk is difficult to interpret in terms of dietary advice to carriers of the various alleles because of conflicting interactions between different genes. The n-3 family of polyunsaturated fatty acids is underrepresented in our modern diet; much of the benefit of polyunsaturated fatty acids found in studies of various polymorphisms seems to be linked to increased n-3 polyunsaturated fatty acid intake. The nascent science of nutrigenomics faces many challenges; more and better research is needed to clarify the picture, rebut scepticism, and re-invigorate the discussion concerning genetic polymorphism and its interaction with diet.

Apolipoprotein A-I↗