bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of 3-methylhistidine production in lambs by using compartmental-kinetic analysis
Authors: Rathmacher J. A. , Link G. , Nissen S.
Published: September 2005

The kinetics of 3-methylhistidine (3MH) metabolism in four crossbred lambs were studied. Each lamb was injected with an intravenous dose of 3-[2H3]methylhistidine (d3-3MH) and the stable isotope disappearance in plasma and appearance in both urine and muscle were measured. Immediately after the administration of tracer there was a phase of rapid disappearance of tracer from the plasma, which was followed by a more gradual decrease in d3-3MH from the plasma during the last 4 d of the experiment. A minimum of three exponentials was required to describe the plasma decay curve adequately. The kinetic model of 3MH in the whole animal was constructed by using the SAAM/CONSAM computer modelling program. Two different configurations of a three-compartment model are described: (1) a simple three-pool model, in which plasma kinetics were entered into pool 1 out of which they had one undefinable exit; (2) a plasma-urinary three-pool model with two exits, in which the urinary kinetics were entered as an exit out of pool 1 and required a second exit out of pool 3 to produce an adequate fit. In addition, muscle kinetics from biopsies of thelongissirnus dorsiwere entered into either pool 2 or 3 using the plasma-urinary model. Steady-state mass and transport rate values were obtained for each model construct described, and ade novoproduction rate corresponding to a fractional breakdown rate of myofibrillar protein of approximately 5%/d was also calculated. The model predicted that only 15% of 3MH was excreted in urine as free 3MH, which is consistent with current knowledge of 3MH excretion in sheep. The simple three-pool plasma kinetic model, therefore, could be used to estimate, by a relatively simple injection-sampling technique, the extent of muscle protein turnover in lambs.
Prevention of oxidative damage in the rat jejunal mucosa by pectin
Authors: Kohen Ron , Shadmi Vered , Kakunda Angel , Rubinstein Abraham
Published: September 2005

The role of the soluble non-starch polysaccharide pectin in the prevention of oxidative damage induced by peroxy, superoxide and hydroxyl radicals to the rat jejunal mucosa was studied. The oxidative stress was introduced to the rat jejunal mucosa by means of a closed-loop perfusion system and was characterized biochemically by monitoring the enterocyte activity of the enzyme lactate dehydrogenase (EC1·1·1·27) and the K+level. Aqueous solutions of pectin were perfused into the rat jejunum before the oxidative stress inducers. The possible protection effect was evaluated by comparing the mucosal integrity (as measured by biochemical variables) to the values obtained after perfusion with the oxidative stress inducers only. We found that: (a) mucosal damage was detected following the perfusion of peroxy and hydroxyl radicals in the rat jejunum, but not following perfusion of the superoxide radical; (b)a significant reduction in the mucosal damage was noted when pectin was perfused before the perfusion with the peroxy radical induction; (c)full protection against the mucosal damage induced by hydroxyl radicals was achieved when pectin was perfused before the damage induction.
Functional capacity of the residual lymphocytes from zinc-deficient adult mice
Authors: Cook-Mills Joan M. , Fraker Pamela J.
Published: September 2005

Zn deficiency has been shown to reduce host defence drastically. It was of interest to determine the capacity of the residual lymphocytes from Zn-deficient mice to proliferate and produce lymphokines in response to stimulation since there are many Zn-dependent metalloenzymes that might be altered by the deficiency. To address this question, young adult A/J mice were provided Zn-deficient or Zn-adequate diets or restricted amounts of a Zn-adequate diet for 30 d. Splenocytes from moderately or severely Zn- deficient adult A/J mice gave normal proliferative responses and generated adequate interleukin II (IL- 2) activity when stimulated with the mitogen Concanavalin A. However, splenocytes from deficient mice exhibited a higher degree of proliferation (about 150%) and production of IL-2 in response to foreign target cells compared with T-cells prepared from mice provided a Zn-adequate diet. B-cells from deficient mice stimulatedin vivowith sheep erythrocytes produced fewer total numbers of plaque-forming cells (PFC) per spleen. Nevertheless, the proportion or number of PFC/106viable splenocytes and the amounts of IgM and IgG antibody produced per PFC were equivalent to those of adequately-fed and restricted-fed controls. The previously described responses were not significantly affected by whether the level of Zn in the culture medium was adequate or limiting. Based on these tests it appeared that the residual splenic lymphocytes of Zn-deficient mice were able to carry out many fundamental immune processes.
Effect of dietary protein quality, feed restriction and short-term fasting on protein synthesis and turnover in tissues of the growing chicken
Authors: Nieto R. , Palmer R. M. , Fernández-Fígares I. , Pérez L. , Prieto C.
Published: September 2005

The effect of dietary protein quality and quantity on fractional rates of protein synthesis (ks) and degradation (kd) in the skeletal muscle, liver, jejunum and skin of young growing chickens was studied. Chickens were either fasted overnight or were fed at frequent intervals, using continuous feeders, with equal amounts of a diet containing soya-bean meal as the sole protein source, unsupplemented, or supplemented with either lysine or methionine. Each of the three diets was provided at 2 or 0.9 × maintenance. On the higher intake, birds on the unsupplemented diet gained weight, lysine supplementation decreased and methionine supplementation increased body-weight gain (by −23% and + 22% respectively). Birds led at 0.9 × maintenance lost weight; supplementation with methionine or lysine did not influence this weight loss. None of the dietary regimens had significant effects on protein synthesis rates in any of the tissues, thus the mechanism whereby muscle mass increased in response to methionine supplementation appeared to be a decrease in the calculated rate of protein degradation. Similarly, on the 0.9 × maintenance diet the failure of the animals to grow appeared to be due to an increase in the rate of protein degradation rather than an effect on synthesis. Conversely, musclekswas decreased in fasted chickens previously fed on the unsupplemented diet at 2 × maintenance, and in birds which had received the 0.9 × maintenance diet fasting resulted in a similar reduction in protein synthesis in muscle;ksin the liver and jejunum was also significantly decreased. The effect of fasting, unlike the effect of supplementation or restriction of the diet, appeared to be due to changes in the rate of protein synthesis.
Simulation of the dynamics of protozoz in the rumen
Authors: Dijkstra Jan
Published: September 2005

A modified mathematical model is described that simulates the dynamics of rumen micro-organisms, with specific emphasis on the rumen protozoa. The model is driven by continuous inputs of nutrients and consists of nineteen state variables, which represent the N, carbohydrate, fatty acid and microbial pools in the rumen. Several protozoal characteristics were represented in the model, including preference for utilization of starch and sugars compared with fibre, and of insoluble compared with soluble protein; engulfment and storage of starch; no utilization of NH3to synthesize amino acids; engulfment and digestion of bacteria and protozoa; selective retention within the rumen; death and lysis related to nutrient availability. Comparisons between model predictions and experimental observations showed reasonable agreement for protozoal biomass in the rumen, but protozoal turnover time was not predicted well. Sensitivity analyses highlighted the need for more reliable estimates of bacterial engulfment rate, protozoal maintenance requirement, and death rate. Simulated protozoal biomass was increased rapidly in response to increases in dietary starch content, but further increases in starch content of a high-concentrate diet caused protozoal mass to decline. Increasing the sugar content of a concentrate diet, decreased protozoa, while moderate elevations of the sugar content on a roughage diet increased protozoal biomass. Simulated protozoal biomass did not change in response to variations in dietary neutral-detergent fibre (NDF) content. Reductions in dietary N resulted in an increased protozoal biomass. Depending on the basal intake level and dietary composition, protozoal concentration in the rumen was either increased or decreased by changes in feed intake level. Such changes in relative amounts of protozoal and bacterial biomass markedly affected the supply of nutrients available for absorption. The integration of protozoal, bacterial and dietary characteristics through mathematical representation provided an improved understanding of mechanisms of protozoal responses to changes in dietary inputs.
Effects of reducing the starch content in oat-based diets with cellulose on jejunal flow and absorption of glucose over an isolated loop of jejunum in pigs
Authors: Johansen Helle N. , Bach knudsen K. E.
Published: September 2005

Four pigs fitted with two sets of re-entrant cannulas in the upper jejunum were used to study the effect of two oat-flour (F)- and oat-bran (B)-based diets without or with (FC and BC respectively) addition of 148 g wood cellulose/kg on jejunal flow and absorption of glucose over an isolated loop of jejunum. Mean transit time (MTT) of flow from the proximal re-entrant cannula increased from approximately 1·5 h with diet F to 2 h when feeding diet BC. Both the replacement of oat flour by oat bran and the supplementation of the diets with cellulose led to a significantly longer MTT for dry matter and the carbohydrates, except that cellulose did not have a significant effect on the MTT for the total non-starch polysaccharides. Only the addition of cellulose significantly delayed gastric emptying of the added liquid-phase (Polyethylene glycol 4000) and solid-phase (Cr2O3) markers, whereas no effect of the oat source used was seen. Feeding diets with a higher level of dietary fibre (DF) and lower content of starch, obtained by substitution with cellulose or by feeding oat bran instead of oat flour, reduced the recovery of starch from an isolated loop of jejunum. Consequently, the quantitative absorption of starch was not significantly different between diets when starch was related to the recovery of external markers. However, when related to the recovery of arabinoxylan (AX) there was a significantly lower absorption of starch from the bran-based diets in comparison with the flour-based diets. The capacity to digest and absorb the large quantities of starch entering the duodenum after a carbohydrate-rich meal appears to be the limiting factor for absorption in the upper jejunum. Therefore, any effect of DF on the rate of absorption of glucose is presumably an effect on gastric emptying rather than displacement of the site of starch absorption in the small intestine.
Pteroyglutamic (folic) acid in different feedstuffs: the pteroylglutamate content and an attempt to measure the bioavailability in pigs
Authors: Matte J. Jacques , Girard Christiane L.
Published: September 2005

Sixty piglets selected after weaning at 4 weeks of age were assigned to five replicates of twelve animals each. In each of these replicates the postprandial variations in serum pteroylglutamate after the ingestion of twelve sources of dietary pteroylglutamic acid were recorded twice weekly at 10 and 16 weeks of age. In six of these sources of pteroylglutamic acid the chemically pure form of the vitamin was incorporated into a semi-purified diet at concentrations varying between 0 and 1·0 mg/kg. The six other sources were provided by a soya-bean meal, rapeseed meal, maize, barley, wheat, and a commercial vitamin premix. The concentrations of pteroylglutamates measured by radioimmunoassay in the different feedstuffs were, in most cases, far from the values reported in the literature, except for maize. Indeed, while total pteroylglutamates in barley, wheat and rapeseed meal were lower by 35–56%. 17–50% and 60% respectively compared with references values, the corresponding values for soya-bean meal ranged from one third to twice as much. The area under the curve (AUC) of the pre- and postprandial (1, 2, 3, 5 and 7 h) serum pteroylglutamate following ingestion of increasing levels of chemically pure pteroylmono- glutamic acid was used to derive a regression for the 100% bioavailability of dietary pteroylglutamic acid. The corresponding AUC for the feedstuff sources of pteroylglutamates were used in the regression to determine the proportion of bioavailable pteroylglutamates out of total pteroylglutamates measured in these ingredients. No relationship (P0·66) was found between the level of chemically pure dietary pteroylmonoglutamic acid and the postprandial AUC. In fact, there was no significant (P0·11) increase in the postprandial concentration of serum pteroylglutamate for any of the pteroylglutamate sources used except for wheat. Moreover, values tended (P0·08) to be lower at 5 and 7 h postfeeding except for wheat and barley. It was hypothesized that this decrease is probably linked to the postfeeding variation in bile secretion which drains considerable amounts of circulatory pteroylglutamates. The results of the present experiment indicate that further research on analytical procedure is needed in order to provide a reliable method for measuring concentrations of pteroylglutamic acid in different sources of a given feedstuff used in pig feeding. In addition to this analytical concern, the measurement of the proportion of bioavailable pteroylglutamic acid in feedstuffs for pigs using postprandial variations of serum pteroylglutamates appears to be technically hazardous.
Effect of baked beans (Phaseoh vulgaris) on steroid metabolism and non-starch polysaccharide output of hypercholesterolaemic pigs with or without an ileo-rectal anastomosis
Authors: Costa Neuza M. B. , Graham Low A. , Walker Ann F. , Owen Robert W. , Englyst Hans N.
Published: September 2005

The plasma-cholesterol-lowering effects of some dietary legumes are now well established from animal and human studies, but the mechanism is not completely understood. The present study investigated the effect of baked beans (Phaseolus vulgaris) on steroid metabolism of hypercholesterolaemic pigs. Three groups of four pigs were studied: baseline (BL), normal pigs (NP) and those previously prepared with an ileo-rectal anastomosis to nullify the function of the large intestine (IR). All three groups were given a semi-purified control diet, with about 40% energy as fat (polyunsaturated: saturated fatty acid (P:S) ratio 0.3), supplemented with 10 g cholesterol/kg, for 14 d. Then IR and NP pigs were fed for 28 d on a diet supplemented with 10 g cholesterol/kg and 300 g baked beans/kg (dry-matter basis), so that the 40% contribution to energy from fat was maintained (P:S ratio 0.3). Group BL was fed on the control diet throughout. The intact pigs (NP) fed on baked beans showed considerable differences compared with the other groups, as follows: (a) reduced plasma cholesterol (NS); (b) higher concentration of cholesterol in bile (NS); (c) higher concentration of bile acids, especially secondary bile acids, in bile (P< 0.05); (d) reduced elimination of bile acids in faeces, especially secondary bile acids (P< 0.05); (e) higher excretion of coprostanol and lower elimination of cholesterol in faeces (P< 0.05). From these findings it is proposed that a baked-bean-enriched diet potentiates bacterial fermentation and steroid degradation in the large intestine and enhances conservation of bile acids and cholesterol within the enterohepatic circulation. The high concentration of bile acids and cholesterol in bile may thus promote feedback inhibition of hepatic cholesterol synthesis, and hence, reduce plasma cholesterol.
Plasma lipid concentrations in children with cystic fibrosis: the value of a high-fat diet and pancreatic supplementation
Authors: Burdge Graham C. , Goodale Alissa J. , Hill Catherine M. , Halford Penny J. , Lambert Elizabeth J. , Postle Anthony D. , Rolles Christopher J.
Published: September 2005

Impaired digestion of dietary fat is an almost universal feature of cystic fibrosis (CF) which results in low concentrations of essential fatty acids in plasma lipids. We have evaluated the effect of a high-lipid diet and pancreatic enzyme supplementation, using enteric-coated microsphere preparations, on plasma lipid concentrations in paediatric CF patients. Absorption of dietary lipid was comparable between control and CF subjects. This resulted in plasma cholesterol, triacylglycerol, total phosphatidylcholine and individual phosphatidylcholine molecular species concentrations in CF patients which were in the same range as those in controls. Normal values for these variables were also found in patients with clinically detectable liver disease. These results show that present dietary management of CF patients supports normal plasma lipid concentrations.
Protein and enery relationships in the broiler chicken 12. Dietary protein and triidothyronine (T3) effects on the response of broilers to isoproterenol and cyclic adenosine monophosphate in vitro
Authors: Rosebrough R.W. , Mitchell A.D.
Published: September 2005

Indian River male broiler chickens (7-d-old) were fed on diets containing 120, 210 or 300 g crude protein/kg + 0 or 1 mg triiodothyronine (T3)/kg diet (Expt 1) and 120, 150, 180 or 210 g crude protein/kg +0 or 1 mg T3/kg diet (Expt 2) to determine the effects of crude protein level and T3on growth and metabolism. Body composition of chickens was determined by a combination of dissection of muscle and abdominal fat pads, and chemical extraction (Expt 1).In vitrolipogenesis (IVL) was determined in both experiments by incubating liver explants for 2 h at 37° in the presence of 10-4M-dibutyryl cyclic AMP (cAMP) or 10-5M isoproterenol (ISO) and 10-2M-[2-14C]acetate. Acetate incorporation into total lipid was an indication of IVL. Activity ratios for each of these additions relative to control (?cAMP?ISO) were calculated to ascertain basal ν. inhibited rates of IVL. The relative muscle mass was increased by increasing crude protein from 120 to 210 g/kg diet but not from 210 to 300 g/kg diet. Dietary T3decreased total body lipid regardless of the dietary crude-protein level. Increasing dietary crude protein decreased (P<0.05) basal IVL (?cAMP? ISO) but not IVL (+ cAMP). Dietary T3decreased basal IVL in birds fed on the diets containing 120 and 210 g crude protein/kg but had little effect on the two inhibited states of lipogenesis (+ cAMP or +ISO). The component of lipogenesis sensitive toin vitroinhibition is also the component under dietary control.
Digestion of raw banana starch in the small intestine of healthy humans: structural features of resistant starch
Authors: Faisant N. , Buléon A. , Colonna P. , Molis C. , Lartigue S. , Galmiche J.P. , Champ M.
Published: September 2005

The digestion of freeze-dried green banana flour in the upper gut was studied by an intubation technique in six healthy subjects over a 14 h period. Of α-glucans ingested, 83.7 % reached the terminal ileum but were almost totally fermented in the colon. Structural study of the resistant fraction showed that a small part of the α-glucans which escaped digestion in the small intestine was composed of oligosaccharides from starch hydrolysis, whereas the rest was insoluble starch in granule form with physical characteristics similar to those of raw banana starch. Passage through the small intestine altered granule structure by increasing susceptibility to further α-amylase hydrolysis. Compared with resistant starch valuesin vivo, those obtained with thein vitromethods tested were inadequate to estimate the whole fraction of starch reaching the terminal ileum.
Food intake in a West African village. Estimation of food intake from a shared bowl
Authors: Hudson Geoffrey J.
Published: September 2005

Novel methodology is described for the estimation of food intake in the particularly difficult circumstance where groups of people eat directly from a shared bowl of cooked food. Detailed observation and measurement of meal preparation is combined with food table values for composition to calculate the nutrient content of each meal. The distribution of food between individuals is estimated by a suitable algorithm. The ability of the algorithm to identify seasonal changes in energy intakes is demonstrated by comparison of the calculated energy intakes with values for the total energy expenditure of free-living adult male subjects, as measured by the stable isotope, doubly-labelled water technique. This comparison suggests that the energy intake calculated from detailed observation of two cooked meals per day is equivalent to approximately 80% of the total energy expenditure and, by inference, total dietary energy intake. The remaining energy intake may well be derived from uncooked ‘snack foods’, such as raw fruit and vegetables, or from cooked food obtained, by purchase or as a gift, away from the home. This is the first description of a successful method for the estimation of food intake when people eat directly from shared bowls of food.
Mechanisms of intestinal phosphate transport in small ruminants
Authors: Schröder B. , Käppner H. , Failing K. , Pfeffer E.
Published: September 2005

In order to study the localization and mechanisms of intestinal phosphate transport in sheep and goats, unidirectional inorganic phosphate (Pi) flux rates across isolated stripped epithelial tissues were measuredin vitroby applying the Ussing-chamber technique. In the first experiment the tissues were obtained from animals which had been kept on an adequate dietary P supply. In the second experiment the animals had either been kept on an adequate Ca and P supply or were Ca- and/or P-depleted. Significant net Piabsorption was measured in all segments of the small intestine and in the proximal colon of sheep and in the duodenum and jejunum of goats. Since the experiments were carried out in the absence of any electrochemical gradient, this clearly indicates the presence of active mechanisms for Pitransport in the intestinal tract of small ruminants. In sheep jejunum, reduction of mucosal Na concentration to 1·8 mM or serosal application of ouabain (0·1 mM) resulted in significant decreases of net F; absorption of the same order of magnitude, indicating that about 65% of active Pitransport in sheep jejunum is mediated by a Na-dependent active transport mechanism. The mechanism for the remaining Na+-independent active Pitransport has not yet been identified. Dietary P depletion caused hypophosphataemia and induced a significant stimulation of net Piabsorption in goat duodenum and jejunum. This increase was independent of dietary Ca supply and was not associated with increased plasma calcitriol concentrations. This suggests substantial differences in hormonal regulation of Pitransport in small ruminants in comparison with single-stomached species.
Honey revisited: a reappraisal of honey in pre-industrial diets
Authors: Allsop Karen A. , Miller Janette Brand
Published: September 2005

In pre-industrial times, honey was the main source of concentrated sweetness in the diets of many peoples. There are no precise figures for per capita consumption during most periods in history because honey was part of either a hunter-gatherer or subsistence economy. Until now, historians and food writers have proposed that it was a scarce commodity available only to a wealthy few. We do know, however, that in a cash economy honey was sold in large units (gallons and even barrels) and it was present in such abundance that mead, made from honey, was a common alcoholic drink. A reappraisal of the evidence from the Stone Age, Antiquity, the Middle Ages and early Modern times suggests that ordinary people ate much larger quantities of honey than has previously been acknowledged. Intakes at various times during history may well have rivalled our current consumption of refined sugar. There are implications therefore for the role of sugar in modern diets. Refined sugar may not have displaced more nutrient-rich items from our present-day diets but only the nutritionally comparable food, honey.
Dual-energy X-ray absorptiometry for the measurement of gross body composition in rats
Authors: Jebb Susan A. , Garland Stephen W , Jennings Graham , Elia Marinos
Published: September 2005

Dual-energy X-ray absorptiometry (DXA) is a novel, non-invasive technique for the measurement of gross body composition in small animals. In the present study the absolute accuracy of the Hologic QDR-lOOOW scanner was assessed by comparison with direct analysis in twelve rats with a range of body fat and bone mineral content (BMC) values. Fat masses measured by DXA and petroleumether extraction were significantly different (P<0·0023). The DXA technique consistently overestimated fat mass by approximately one third of the measured fatcontent. BMC derived from the measurement of Ca in asb gave a mean of 8·26 (range 1·57–15·71)g. BMC measured by DXA was not significantly different for the group as a whole. However, there was a trend for DXA to overestimate BMC in animals with low BMC and underestimate in those with higher BMC, compared with direct analysis, such that the 95% limits of agreement for the two techniques were +2·73 to −2·58g. These results suggest that the present small-animal software developed for use with currently available Hologic machines does not give an accurate measure of gross body composition compared with the results from classical direct analysis.
Postprandial coagulation factor VII activity: the effect of monounsaturated fatty acids
Authors: Roche Helen M. , Gibney Michael J.
Published: September 2005

The present study investigated the effect of monounsaturated fatty acids (MUFA) on postprandial coagulation factor VII activity. Fifteen healthy male volunteers consumed three meals containing equal amounts (40g) of fat, but providing different proportions of MUFA (12,17 and 24% energy)in random order. Fasting and postprandial blood samples were drawn every hour for 9 h. The magnitude of the postprandial triacylglycerolaemic response and the postprandial plasma nonesterifled fatty acid (NEFA) concentrations were not significantly different following the three meals. Coagulation factor VII was activated during postprandial triacylglycerolaemia but the area under the curve of postprandial coagulation factor VII activity was not significantly different following the three meals. Regression analysis showed that fasting factor VII activity was the single mast important factor affecting postprandial factor VII activity, irrespective of plasma lipid concentrations and meal fat composition. Peak postprandial factor VII activity was attained significantly earlier following the high-MUFA meal compared with the low-MUFA meal (6·33 (SD 2·16) h, 3·60 (SD 1·81)h respectively; P = 0·016). Regression analysis showed that meal MUFA content was the primary determinant of time to peak postprandial factor VII activity. Although the magnitude of postprandial coagulation factor VII activity was not affected by meal MUFA content, peak postprandial factor VII activity occurred earlier and fasting activity levels were quickly restored following the high-MUFA meal. A short-lived increase in factor VII activity may be more beneficial than a prolonged thrombotic response.
Net flux of nutrients across splanchnic tissues in wethers consuming grasses of different sources and physical forms ad libitum
Authors: Goetsch A.L. , Patil A. R. , Galloway D.L. , Kouakou B. , Wang Z.S. , Park K.K. , Rossi J.E.
Published: September 2005

Crossbred sheep (n 16,8·5 months of age and 33 (SE 0·9) kg) were used in a 21 d experiment (2x2 factorial) to determine effects on net flux of nutrients across the portal-drained viscera (PDV) and liver of ad libitum consumption of bermudagrass (Cynodon dactylon; B) v. ryegrass (Lolium multiflorum)-wheat (Triticum aestivum; RW) hay, coarsely chopped (CC) or finely ground and pelleted (GP). Crude protein concentrations were 86, 81, 113 and 119g/kg and neutral-detergent fibre concentrations were 710, 688, 654 and 672 g/kg (dry matter basis) for B-CC, B-GP, RW-CC and RW-GP respectively. Digestible energy intake (6.0,9.6·, 10·2 and 13·8 W/d) Mered (P < 0·01) with grass source and form, and digestible N intake values were 4·4, 7·0, 8·4 and 14.1 (SEM 0·82) g/d for B-CC, B-GP, RW-CC and RW-GP diets respectively. Consumption of O2 by the PDV (118,165,144 and 155mmol/h) and splanchnic bed (196,273,247 and 266 mmollh for B-CC, B-GP, RW-CC and RW-GP respectively) was greater (P=O·O7) for GP than for CC. The ratio splanchnic heat energy production: digestible energy intake was greater (P=0·06) for B than for RW (0·374,0·300,0·278 and 0·219 for B.CC, B-GP, RW-CC and RW-GP respectively). α-Amino-N release by the PDV (P< 0·01; 11·6, 12·8, 23·0 and 18·7 mmoyh) and uptake by the liver (P=0·07; 15·2, 6·1, 17·0 and 19·3 mmol/h for B-CC, B-GP, RW-CC and RW-GP respectively) were greater for RW than for B. Release of NH3-N by the PDV was greater (P=O·02) for CC than for GP (12·5, 6·2, 15·7 and 8·9 mmol/h), and hepatic urea-N release differed between grass sources (P=O·O3) and physical forms (P=0·07; 22·6, 12·7, 31·4 and mmol/h for B-CC, B-GP, RW-CC and RW-GP respectively). In conclusion, decreases in forage particle size elicited by grinding and pelleting did not affect the difference between grass sources in splanchnic tissue heat energy production relative to digestible energy intake.
Prevalence and haemopoietic effects of low serum vitamin B12levels in geriatric medical patients
Authors: Stott David J. , Langhorne Peter , Hendry Anne , Mckay Pamela J , Holyoake Tessa , Macdonald Jon , Lucie Norman
Published: September 2005

The clinical significance of low serum vitamin B12levels in elderly people is controversial. We aimed to document the prevalence of a low serum vitamin B12(<175pmol/l) in patients referred to a geriatric medical unit, and to determine whether haemopoiesis is commonly affected in elderly patients with low serum vitamin B12. We studied prospectively 472 consecutive referrals to a geriatric medical unit; fifty-six (13%) had a low serum vitamin B12level, of whom nineteen (34%) of the fifty-six also had evidence of Fe deficiency (serum ferritin<45ng/ml). Low vitamin B12was associated with a raised mean erythrocyte volume (MCV; mean 96·0 (SD 6·7) fl), compared with a control group (91·7 (SD 6·0) fl; P=0·001). However, only thirteen (23%) of the fifty-six patients with a low vitamin Blz had an MCV≥100 fl. Mean haemoglobin (Hb) levels were not significantly reduced in those with a low vitamin B12. In a subsequent study the haematological response to intramuscular hydroxocobalamin was examined in thirty-four patients with a low serum vitamin B12. Treatment resulted in a significant fall in MCV and rise in Hb; these effects could be detected both in those patients with an initially normal full blood count (change in MCV -1·2 (SD 1·2); Hb + 0·5 (SD 0·6); P<0·01) and in those with macrocytosis and/or anaemia (-9·1 (SD 11·8); + 0·8 (SD 1·2); P<0·05). A low serum vitamin B12is common in geriatric medical patients. This is usually associated with an upset in erythropoiesis, although the abnormalities are often subtle and may not be apparent on inspection of the full blood count. Elderly patients with serum vitamin B12<175pmol/l should be assumed to have vitamin deficiency even if their full blood count is normal.
Digestion and metabolism of dietary fat in farm animals
Authors: Doreau Michel , Chilliard Yves
Published: September 2005

Fat digestion and metabolism differ widely between animal species. In ruminants, dietary fats are hydrogenated in the rumen before intestinal absorption so that absorbed fatty acids (FA) are more saturated than dietary FA. In non-ruminants, intestinal FA digestibility depends on the level of saturation of dietary FA. Fat supplementation of the diet of cows decreases milk protein and has a variable effect on milk fat, depending on the source of dietary lipids. When encapsulated lipids are used, the linoleic acid content of milk is increased, but the organoleptic quality of milk may be altered. Supplementary lipids are incorporated into non-ruminant body fat, whereasde novolipogenesis is reduced. There is a close relationship between the nature of dietary FA and non-ruminant body FA.
The C. elegans p38 MAPK pathway regulates nuclear localization of the transcription factor SKN-1 in oxidative stress response
Authors: Inoue Hideki , Hisamoto Naoki , An Jae Hyung , Oliveira Riva P. , Nishida Eisuke , Blackwell T. Keith , Matsumoto Kunihiro
Published: September 2005

The evolutionarily conserved p38 mitogen-activated protein kinase (MAPK) cascade is an integral part of the response to a variety of environmental stresses. Here we show that the Caenorhabditis elegans PMK-1 p38 MAPK pathway regulates the oxidative stress response via the CNC transcription factor SKN-1. In response to oxidative stress, PMK-1 phosphorylates SKN-1, leading to its accumulation in intestine nuclei, where SKN-1 activates transcription of gcs-1, a phase II detoxification enzyme gene. These results delineate the C. elegans p38 MAPK signaling pathway leading to the nucleus that responds to oxidative stress.
The Yeast Gene Order Browser: Combining curated homology and syntenic context reveals gene fate in polyploid species
Authors: Byrne Kevin P. , Wolfe Kenneth H.
Published: September 2005

We developed the Yeast Gene Order Browser (YGOB; http://wolfe.gen.tcd.ie/ygob) to facilitate visual comparisons and computational analysis of synteny relationships in yeasts. The data presented in YGOB, currently covering seven species, are based on sets of homologous genes that have been intensively manually curated based on both sequence similarity and genomic context (synteny). We reconciled different laboratories' lists of paralogous Saccharomyces cerevisiae gene pairs formed by genome duplication (ohnologs), and present near-exhaustive lists of the ohnolog pairs retained in S. cerevisiae (551, including 22 previously unidentified), Saccharomyces castellii (599), and Candida glabrata (404).
Origin and primary dispersal of the Mycobacterium tuberculosis Beijing genotype: Clues from human phylogeography
Authors: Mokrousov Igor , Ly Ho Minh , Otten Tatiana , Lan Nguyen Ngoc , Vyshnevskyi Boris , Hoffner Sven , Narvskaya Olga
Published: September 2005

We suggest that the evolution of the population structure of microbial pathogens is influenced by that of modern humans. Consequently, the timing of hallmark changes in bacterial genomes within the last 100,000 yr may be attempted by comparison with relevant human migrations. Here, we used a lineage within Mycobacterium tuberculosis, a Beijing genotype, as a model and compared its phylogeography with human demography and Y chromosome-based phylogeography. We hypothesize that two key events shaped the early history of the Beijing genotype: (1) its Upper Palaeolithic origin in the Homo sapiens sapiens K-M9 cluster in Central Asia, and (2) primary Neolithic dispersal of the secondary Beijing NTF::IS6110 lineage by Proto-Sino-Tibetan farmers within east Asia (human O-M214/M122 haplogroup). The independent introductions of the Beijing strains from east Asia to northern Eurasia and South Africa were likely historically recent, whereas their differential dissemination within these areas has been influenced by demographic and climatic factors.
Living with two extremes: Conclusions from the genome sequence of Natronomonas pharaonis
Authors: Falb Michaela , Pfeiffer Friedhelm , Palm Peter , Rodewald Karin , Hickmann Volker , Tittor Jörg , Oesterhelt Dieter
Published: September 2005

Natronomonas pharaonis is an extremely haloalkaliphilic archaeon that was isolated from salt-saturated lakes of pH 11. We sequenced its 2.6-Mb GC-rich chromosome and two plasmids (131 and 23 kb). Genome analysis suggests that it is adapted to cope with severe ammonia and heavy metal deficiencies that arise at high pH values. A high degree of nutritional self-sufficiency was predicted and confirmed by growth in a minimal medium containing leucine but no other amino acids or vitamins. Genes for a complex III analog of the respiratory chain could not be identified in the N. pharaonis genome, but respiration and oxidative phosphorylation were experimentally proven. These studies identified protons as coupling ion between respiratory chain and ATP synthase, in contrast to other alkaliphiles using sodium instead. Secretome analysis predicts many extracellular proteins with alkaline-resistant lipid anchors, which are predominantly exported through the twin-arginine pathway. In addition, a variety of glycosylated cell surface proteins probably form a protective complex cell envelope. N. pharaonis is fully equipped with archaeal signal transduction and motility genes. Several receptors/transducers signaling to the flagellar motor display novel domain architectures. Clusters of signal transduction genes are rearranged in haloarchaeal genomes, whereas those involved in information processing or energy metabolism show a highly conserved gene order.
Determination of Catalytic Key Amino Acids and UDP Sugar Donor Specificity of the Cyanohydrin Glycosyltransferase UGT85B1 from Sorghum bicolor. Molecular Modeling Substantiated by Site-Specific Mutagenesis and Biochemical Analyses
Authors: Thorsøe Karina Sinding , Bak Søren , Olsen Carl Erik , Imberty Anne , Breton Christelle , Lindberg Møller Birger
Published: September 2005

Plants produce a plethora of structurally diverse natural products. The final step in their biosynthesis is often a glycosylation step catalyzed by a family 1 glycosyltransferase (GT). In biosynthesis of the cyanogenic glucoside dhurrin in Sorghum bicolor, the UDP-glucosyltransferase UGT85B1 catalyzes the conversion of p-hydroxymandelonitrile into dhurrin. A structural model of UGT85B1 was built based on hydrophobic cluster analysis and the crystal structures of two bacterial GTs, GtfA and GtfB, which each showed approximately 15% overall amino acid sequence identity to UGT85B1. The model enabled predictions about amino acid residues important for catalysis and sugar donor specificity. p-Hydroxymandelonitrile and UDP-glucose (Glc) were predicted to be positioned within hydrogen-bonding distance to a glutamic acid residue in position 410 facilitating sugar transfer. The acceptor was packed within van der Waals distance to histidine H23. Serine S391 and arginine R201 form hydrogen bonds to the pyrophosphate part of UDP-Glc and hence stabilize binding of the sugar donor. Docking of UDP sugars predicted that UDP-Glc would serve as the sole donor sugar in UGT85B1. This was substantiated by biochemical analyses. The predictive power of the model was validated by site-directed mutagenesis of selected residues and using enzyme assays. The modeling approach has provided a tool to design GTs with new desired substrate specificities for use in biotechnological applications. The modeling identified a hypervariable loop (amino acid residues 156–188) that contained a hydrophobic patch. The involvement of this loop in mediating binding of UGT85B1 to cytochromes P450, CYP79A1, and CYP71E1 within a dhurrin metabolon is discussed.
Epidermal Cell Death in Rice Is Regulated by Ethylene, Gibberellin, and Abscisic Acid
Authors: Steffens Bianka , Sauter Margret
Published: September 2005

Programmed cell death (PCD) of epidermal cells that cover adventitious root primordia in deepwater rice (Oryza sativa) is induced by submergence. Early suicide of epidermal cells may prevent injury to the growing root that emerges under flooding conditions. Induction of PCD is dependent on ethylene signaling and is further promoted by gibberellin (GA). Ethylene and GA act in a synergistic manner, indicating converging signaling pathways. Treatment of plants with GA alone did not promote PCD. Treatment with the GA biosynthesis inhibitor paclobutrazol resulted in increased PCD in response to ethylene and GA presumably due to an increased sensitivity of epidermal cells to GA. Abscisic acid (ABA) was shown to efficiently delay ethylene-induced as well as GA-promoted cell death. The results point to ethylene signaling as a target of ABA inhibition of PCD. Accumulation of ethylene and GA and a decreased ABA level in the rice internode thus favor induction of epidermal cell death and ensure that PCD is initiated as an early response that precedes adventitious root growth.
Sorghum Expressed Sequence Tags Identify Signature Genes for Drought, Pathogenesis, and Skotomorphogenesis from a Milestone Set of 16,801 Unique Transcripts
Authors: Pratt Lee H. , Liang Chun , Shah Manish , Sun Feng , Wang Haiming , Reid St. Patrick , Gingle Alan R. , Paterson Andrew H. , Wing Rod , Dean Ralph , Klein Robert , Nguyen Henry T. , Ma Hong-mei , Zhao Xin , Morishige Daryl T. , Mullet John E. , Cordonnier-Pratt Marie-Michèle
Published: September 2005

Improved knowledge of the sorghum transcriptome will enhance basic understanding of how plants respond to stresses and serve as a source of genes of value to agriculture. Toward this goal, Sorghum bicolor L. Moench cDNA libraries were prepared from light- and dark-grown seedlings, drought-stressed plants, Colletotrichum-infected seedlings and plants, ovaries, embryos, and immature panicles. Other libraries were prepared with meristems from Sorghum propinquum (Kunth) Hitchc. that had been photoperiodically induced to flower, and with rhizomes from S. propinquum and johnsongrass (Sorghum halepense L. Pers.). A total of 117,682 expressed sequence tags (ESTs) were obtained representing both 3′ and 5′ sequences from about half that number of cDNA clones. A total of 16,801 unique transcripts, representing tentative UniScripts (TUs), were identified from 55,783 3′ ESTs. Of these TUs, 9,032 are represented by two or more ESTs. Collectively, these libraries were predicted to contain a total of approximately 31,000 TUs. Individual libraries, however, were predicted to contain no more than about 6,000 to 9,000, with the exception of light-grown seedlings, which yielded an estimate of close to 13,000. In addition, each library exhibits about the same level of complexity with respect to both the number of TUs preferentially expressed in that library and the frequency with which two or more ESTs is found in only that library. These results indicate that the sorghum genome is expressed in highly selective fashion in the individual organs and in response to the environmental conditions surveyed here. Close to 2,000 differentially expressed TUs were identified among the cDNA libraries examined, of which 775 were differentially expressed at a confidence level of 98%. From these 775 TUs, signature genes were identified defining drought, Colletotrichum infection, skotomorphogenesis (etiolation), ovary, immature panicle, and embryo.
Nitric Oxide Mediates the Fungal Elicitor-Induced Hypericin Production of Hypericum perforatum Cell Suspension Cultures through a Jasmonic-Acid-Dependent Signal Pathway
Authors: Xu Mao-Jun , Dong Ju-Fang , Zhu Mu-Yuan
Published: September 2005

Fungal elicitor prepared from the cell walls of Aspergillum niger induces multiple responses of Hypericum perforatum cells, including nitric oxide (NO) generation, jasmonic acid (JA) biosynthesis, and hypericin production. To determine the role of NO and JA in elicitor-induced hypericin production, we study the effects of NO scavenger 2- to 4-carboxyphenyl-4,4, 5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPITO), nitric oxide synthase inhibitor S,S′-1,3-phenylene-bis(1,2-ethanediyl)-bis-isothiourea, and inhibitors of the octadecanoid pathway on elicitor-induced NO generation, JA biosynthesis, and hypericin production. Pretreatment of the cells with cPITO and JA biosynthesis inhibitors suppresses not only the elicitor-induced NO generation and JA accumulation but also the elicitor-induced hypericin production, which suggests that both NO and JA are involved in elicitor-induced hypericin biosynthesis. S,S′-1,3-phenylene-bis(1,2-ethanediyl)-bis-isothiourea and cPITO inhibit both elicitor-induced NO generation and JA biosynthesis, while JA biosynthesis inhibitors do not affect the elicitor-induced NO generation, indicating that JA acts downstream of NO generation and that its biosynthesis is regulated by NO. External application of NO via its donor sodium nitroprusside induces hypericin production in the absence of fungal elicitor. Sodium-nitroprusside-induced hypericin production is blocked by JA biosynthesis inhibitors, showing that JA biosynthesis is essential for NO-induced hypericin production. The results demonstrate a causal relationship between elicitor-induced NO generation, JA biosynthesis, and hypericin production in H. perforatum cells and indicate a sequence of signaling events from NO to hypericin production, within which NO mediates the elicitor-induced hypericin biosynthesis at least partially via a JA-dependent signaling pathway.
Experimental determination of the X-ray attenuation coefficient of In at 8.047 keV
Authors: Ferrari Claudio , Verdi Nicola , Motta Alberto
Published: September 2005

An experimental value of μ/ρIn= 235.3 cm2 g−1for the In attenuation coefficient with a Cu Kα wavelength has been determined with an improved accuracy of ±1%, by measuring the X-ray beam absorption of an In film deposited on an aluminium foil in which the total In content was determined by weighing the sample. To avoid errors in the absorption measurements due to the non-uniform layer thickness, the absorption was mapped and averaged over the whole sample area. The μ/ρInvalue obtained is 2.6% lower than the values obtained fromInternational Tables of Crystallography(Vol. IV, 1974, pp. 47–70) and 7% lower than a recent experimental value. The value determined is essentially in agreement with data calculated from recent theoretical models. The method proposed can be applied to several other materials that can be deposited as thin layers on a light absorber.
Space group determination: improvements inEXPO2004
Authors: Altomare Angela , Camalli Mercedes , Cuocci Corrado , da Silva Iván , Giacovazzo Carmelo , Moliterni Anna Grazia Giuseppina , Rizzi Rosanna
Published: September 2005

In the ideal process for crystal structure solution, the determination of the space group usually follows the indexation step. When powder data are used, peak overlap, background definition and possible impurity peaks may hinder the identification of the correct extinction group. The recent automatic procedure implemented inEXPO2004has been further developed; the modifications are based on additional statistical criteria, with new algorithms for a better definition of the background and for the removal of impurity peaks. The new version also offers a more powerful graphical interface. Failures occur rarely, as shown by examples.
dSNAP: a computer program to cluster and classify Cambridge Structural Database searches
Authors: Barr Gordon , Dong Wei , Gilmore Christopher J. , Parkin Andrew , Wilson Chick C.
Published: September 2005

A computer program that automatically classifies and clusters structural fragments extracted from mining the Cambridge Structural Database is described. The methodology is based on cluster analysis and multivariate data processing of distance matrix information describing the extracted fragments. Coupled with the calculations is a set of visualization tools that enable the user to view and verify the proposed classification scheme, and further explore it in varying levels of detail. Two examples are presented: the first is based on a simple difluoroalkene fragment and the second, more complex, on a chiral vicinal dialcohol,R1(OH)CHCH(OH)R2.