Rowett Research Institute

About: Rowett Research Institute is a based out in . It is known for research contribution in the topics: Rumen & Population. The organization has 2986 authors who have published 4459 publications receiving 239472 citations.

The Epidemiology of Obesity

Abstract: An agreed definition of obesity as a body mass index (BMI) of 30 kg/m2 or more seems to be accepted everywhere except in North America. Recent data confirm the importance of setting an upper individual BMI limit of 25 kg/m2 and a population optimum of 20-23 kg/m2. Some adjustment of BMI should be made in individuals and populations with disproportionate shapes, e.g. short or long legs, and morbidity and mortality risks are especially important in those with a waist measurement of about 102 cm or more, the risk increasing from 88 cm. Waist measurements should probably now be substituted for the waist/hip circumference ratio. Diabetes is universally closely linked to increases in BMI, and cardiovascular disease is amplified by obesity, particularly in western societies where other dietary factors contribute substantially. Industrialization with reduced physical activity and higher fat diets lead to obesity first in middle-aged women, then in men, with younger adults and children eventually being affected. Physiological studies display the interaction of physical activity and energy dense, high fat diets and explain the secular, age- and social class-related trends throughout the world. Intergenerational amplification of obesity may be underway, so the public health implications of obesity are immense.

Vitamin E requirements, transport, and metabolism: Role of α-tocopherol-binding proteins☆

Abstract: Vitamin E (RRR-α-tocopherol) is a lipid-soluble antioxidant that is present in the membranes of intracellular organelles. There it plays an important role in the suppression of free radical-induced lipid peroxidation. There are eight naturally occurring homologues of vitamin E that differ in their structure and in biological activity in vivo and in vitro. Although γ-tocopherol is a more effective free radical scavenger than α-tocopherol in vitro, the reverse is true in vivo, suggesting that the tocopherol distribution systems favor the localization of α-tocopherol at the sites where it is required. Vitamin E is transported in plasma primarily by lipoproteins, but little is known of how it is transported intracellularly. A 30 kDa α-tocopherol-binding protein in the liver cytoplasm may regulate plasma vitamin E concentrations by preferentially incorporating the vitamin E homologue, RRR-α-tocopherol (α-tocopherol), into nascent very low density lipoproteins. However, this α-tocopherol-binding protein is unique to the hepatocyte, whereas α-tocopherol is present in the cells of all major tissues. Moreover α-tocopherol accumulates at those sites within the cell where oxygen radical production is greatest and thus where it is most required; in the membranes of heavy mitochondria, light mitochondria, and endoplasmic reticulum. This raises the question of how the lipid-soluble α-tocopherol is transported intracellularly in different tissues. We have identified a new α-tocopherol-binding protein of molecular mass 14.2 kDa in the cytosol of heart and liver. This protein specifically binds α-tocopherol in preference to the δ- and γ-homologues but does not bind oleate. Studies on immunoreactivity and ligand specificity of the protein suggest that it is not a fatty acid-binding protein. The 14.2 kDa α-tocopherol-binding protein stimulates the transfer of α-tocopherol from liposomes to mitochondria in vitro by 8 to 10 fold. We suggest that this low molecular mass TBP may be responsible for the intracellular transport and distribution of α-tocopherol in the tissues.

Annexin A2 binds to the localization signal in the 3′ untranslated region of c‐myc mRNA

Abstract: Messenger RNA trafficking, which provides a mechanism for local protein synthesis, is dependent on cis-acting sequences in the 3′ untranslated regions (3′UTRs) of the mRNAs concerned acting together with trans-acting proteins. The C-MYC transcription factor is a proto-oncogene product involved in cell proliferation, differentiation and apoptosis. Localization of c-myc mRNA to the perinuclear cytoplasm and its association with the cytoskeleton is determined by a signal in the 3′UTR. Here we show the specific binding of a trans-acting factor to the perinuclear localization element in the 3′UTR of c-myc mRNA and identify this protein as annexin A2. Gel retardation and UV cross-linking experiments showed that proteins in fibroblast extracts formed complexes with the region of c-myc 3′UTR implicated in localization; a protein of ≈ 36 kDa exhibited specific, Ca2+-dependent binding. Binding was reduced by introduction of a mutation that abrogates localization. Using RNA-affinity columns followed by gel electrophoresis and mass spectrometry this protein was identified as annexin A2. The RNA–protein complex formed by cell extracts was further retarded by anti-(annexin A2). Purified annexin A2 bound to the same region of the c-myc 3′UTR but binding was reduced by introduction of a mutation, as with cell extracts. It is proposed that binding of annexin A2 to the localization signal in the c-myc mRNA leads to association with the cytoskeleton and perinuclear localization. The data indicate a novel functional role for the RNA-binding properties of annexin A2 in perinuclear localization of mRNA and the association with the cytoskeleton.

The toxicity of Phaseolus vulgaris lectins. Nitrogen balance and immunochemical studies

Abstract: Inclusion of pure lectins isolated from the seeds of kidney bean (Phaseolus vulgaris L. cv. Processor) in diets for rats increased both faecal and urinary losses of N and resulted in a negative N balance for the animals. The relationship between total body N change [y (mg)] and lectin concentration [x (g kg−1)] of the diet was: y=421.5-75.1 x, which was statistically significant (P=0.05). These rats developed circulating antibodies of low avidity to the dietary lectins, while no other proteins of the diet elicited a similar antibody response. Additionally, in several serum samples from rats which had been fed raw beans, the presence of small amounts of a protein reactive with rabbit anti-lectin antibodies was detected. This protein was isolated from the immune precipitate and was shown by sodium dodecylsulphate-gel electrophoresis to contain a protein subunit of 30 000, which was very similar to that of pure lectins. It is tentatively suggested that lectin toxicity results from the combined effects of the interference with normal intestinal digestion and/or absorption of N through the damaged enterocytes and of systemic immune (and other) responses of the rat to the internalised lectin.

Fermentation of barley straw by anaerobic rumen bacteria and fungi in axenic culture and in co‐culture with methanogens

Abstract: When incubated in axenic culture, strains of anaerobic rumen fungi were more active than cellulolytic bacteria in solubilizing barley straw stem fragments 5 to 10 mm in length. Pretreatment with ammonia had little effect on microbial attack. Of three species of methanogens tested, Methanobrevibacter smithii strain PS formed the most stable and reproducible co-cultures with the fungi and with Ruminococcus albus, and the presence of this organism enhanced the extent of degradation of straw, although this effect was less marked than that previously observed when pure cellulose was used as substrate.