Search

Aims We sought to define the influence of verapamil, an inhibitor of CYP3A and P-glycoprotein, on the pharmacokinetics of everolimus, a substrate of this enzyme and transporter. Methods This was a two-period, single-sequence, crossover study in 16 healthy subjects. In period 1 subjects received a single 2 mg oral dose of everolimus. In period 2 they received verapamil 80 mg three times daily for a total of 6 days and a single 2 mg dose of everolimus co-administered on the second day of verapamil therapy. Results During verapamil co-administration, everolimus Cmax increased 2.3-fold (90% CI, 1.9, 2.7) from 21 ± 8 to 47 ± 18 ng ml−1 and AUC increased 3.5-fold (90% CI, 3.1, 3.9) from 115 ± 45 to 392 ± 142 ng ml−1 h. Everolimus half-life was only prolonged to a minor extent (32 ± 6 vs. 37 ± 6 h). Verapamil predose concentrations doubled from 32 ± 16 to 74 ± 42 ng ml−1 after single dose administration of everolimus. Conclusions Multiple dosing with verapamil increased blood concentrations of everolimus after a single dose by an average 3.5-fold. During verapamil treatment, dose reduction for everolimus should be made guided by blood monitoring and for verapamil by blood pressure monitoring.

Synergistes jonesii is a rumen bacterium that degrades toxic pyridinediols from Leucaena leucocephala. This work presents progress on the characterization of the degradation of dihydroxypyridines from L. leucocephala by S. jonesii, and particularly by its cell free extracts. The substrate 3-hydroxy-4-[1H]-pyridone (3,4-DHP) induced degradation of both 3,4- and 2,3-dihydroxypyridine (2,3-DHP) isomers, while 2,3-DHP induced only degradation of 2,3-DHP. The 2,3-DHP was an intermediate of the degradation of 3,4-DHP by cultures. The compound 2,6-dihydroxypyridine inhibited degradation of 2,3-DHP by extracts of cells previously induced with this substrate. Cell-free extracts from S. jonesii had a high hydrogenase activity and degraded 2,3-DHP anaerobically either in the presence of methyl viologen under H2 or in the presence of α-ketoacids under H2 or N2. Specific activity of 2,3-DHP degradation was increased when FAD+ or CoA were present. The pyridine ring of the 2,3-DHP is enzymatically reduced by S. jonesii in reactions that demand reducing power provided by hydrogenase activity or by the metabolism of pyruvate. An unidentified non-polar amino compound appeared in thin layer chromatography as 2,3-DHP was degraded. We anticipate that gas chromatography mass spectrometry will permit the purification and identification of products from the cell-free reaction mix, which represents a simpler system than cell cultures, so that a pathway for pyridinediol metabolism by S. jonesii can be proposed.

Several magnetic resonance (MR) parallel imaging techniques require explicit estimates of the receive coil sensitivity profiles. These estimates must be accurate over both the object and its surrounding regions to avoid generating artifacts in the reconstructed images. Regularized estimation methods that involve minimizing a cost function containing both a data-fit term and a regularization term provide robust sensitivity estimates. However, these methods can be computationally expensive when dealing with large problems. In this paper, we propose an iterative algorithm based on variable splitting and the augmented Lagrangian method that estimates the coil sensitivity profile by minimizing a quadratic cost function. Our method, ADMM–Circ, reformulates the finite differencing matrix in the regularization term to enable exact alternating minimization steps. We also present a faster variant of this algorithm using intermediate updating of the associated Lagrange multipliers. Numerical experiments with simulated and real data sets indicate that our proposed method converges approximately twice as fast as the preconditioned conjugate gradient method (PCG) over the entire field-of-view. These concepts may accelerate other quadratic optimization problems.

Reducing sugar content, and activities of three starch hydrolysing enzymes, alpha-amylase, beta-amylase and debranching enzyme were measured over several months in tubers of five cultivars stored at 4°C or 10°C. Cultivars differed in their sensitivity to storage temperature. Reducing sugar content of tubers and the activities of three starch hydrolysing enzymes increased sharply during the first weeks of storage at 4°C. At 10°C, reducing sugar content, and the activity of the three enzymes remained constant or increased only slightly.

Low temperature sweetening is a major problem to chip and crisp manufacturers as it results in the production of unacceptably dark fry products. Cryo-electron microscopy was used to examine the changes which occur to the surface morphology of starch granules from tubers of cultivars Record and Brodick stored at 4°C and 10°C. At harvest, the surface of the starch granules was smooth but during storage the surface of the granules became progressively more pitted. The feasibility of using this technique to determine whether increased starch breakdown occurs at low storage temperatures is discussed.

We had proposed earlier that the anaerobe Oxalobacter formigenes sustains a proton-motive force by exploiting a secondary carrier rather than a primary proton pump. In this view, a carrier protein would catalyze the exchange of extracellular oxalate, a divalent anion, and intracellular formate, the monovalent product of oxalate decarboxylation. Such an electrogenic exchange develops an internally negative membrane potential, and since the decarboxylation reaction consumes an internal proton, the combined activity of the carrier and the soluble decarboxylase would constitute an "indirect" proton pump with a stoichiometry of 1H+ per turnover. This model is now verified by identification and purification of OxlT, the protein responsible for the anion exchange reaction. Membranes of O. formigenes were solubilized at pH 7 with 1.25% octyl glucoside in 20 mM 3-(N-morpholino)propanesulfonic acid/K, in the presence of 0.4% Escherichia coli phospholipids and with 20% glucerol present as the osmolyte stabilant. Rapid methods for reconstitution were developed to monitor the distribution of OxlT during biochemical fractionation, allowing its purification by sequential anion and cation exchange chromatography. OxlT proved to be a single hydrophobic polypeptide, of 38 kDa mobility during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with a turnover number estimated as at least 1000/s. The properties of OxlT point to an indirect proton pump as the mechanism by which a proton-motive force arises in O. formigenes, and one may reasonably argue that indirect proton pumps take part in bacterial events such as acetogenesis, malolactate fermentation, and perhaps methanogenesis.

OxlT, a secondary carrier found in Oxalobacter formigenes, mediates the exchange of divalent oxalate and monovalent formate. Because OxlT has an unusually high turnover number (greater than or equal to 1000/s), and because formate, one its substrates, shows high passive membrane permeability as formic acid, it has been difficult to obtain information on protein-substrate interactions using traditional methods in membrane biology. For this reason, we devised a new way to measure substrate dissociation constants. Detergent-solubilized material was exposed to inactivating temperatures in the absence or presence of OxlT substrates, and periodic reconstitution was used to monitor the kinetics of thermal decay. The data were consistent with a simple scheme in which only unliganded OxlT was temperature-sensitive; this premise, along with the assumption of equilibrium between liganded and unliganded species, allowed calculation of substrate dissociation constants for oxalate (18 +/- 3 microM), malonate (1.2 +/- 0.2 mM), and formate (3.1 +/- 0.6 mM). Further analysis revealed that substrate binding energy contributed at least 3.5 kcal/mol to stabilization of solubilized OxlT. Accordingly, we suggest that substrate binding energy is directly involved in driving protein structure reorganization during membrane transport. This new approach to analyzing protein-substrate interactions may have wider application in the study of membrane carriers.

This paper examines the benefits and problems that have arisen from the use of xenobiotics in modern agriculture. Factors which control the transport and metabolism of xenobiotic molecules in plants and soils are considered, with emphasis being placed on the identification of topics which, in the opinion of the authors, are appropriate for increased research activity. The various approaches that are currently used for the analysis of xenobiotic residues in biological materials are also reviewed briefly.

Methods for the estimation of amylolytic activity are reviewed. A procedure for the routine extraction of amylolytic activity from freeze-dried powder prepared from potato tubers is described. The extraction medium is buffered at pH 7.0 and contains glycerol, dithiothreitol, calcium chloride and the non-ionic detergent, nonidet P-40. α-Amylase activity and exoamylolytic activity were estimated in crude extracts of potato tubers using the substrates, blockedp-nitrophenyl-maltoheptaoside andp-nitrophenyl-maltopentaoside respectively. These substrates are included in kits supplied by Biocon, (UK) Ltd to measure the α- and s-amylase activity in cereals. The validity of using these kits for the determination of α- and s-amylase activity in potato tuber tissue is discussed.

Tubers of the potato cultivars Record, Wilja, Pentland Dell and Brodick (formerly clone 137371) were sampled before and after storage at either 4°C or 10°C. Reducing sugar content stayed constant during storage at 10°C in all four cultivars but rose greatly during the first 6–12 weeks of storage at 4°C in Record, Wilja and Pentland Dell but not in Brodick. Amylolytic activity was determined after 5 weeks storage using blockedp-nitrophenyl maltoheptaoside as substrate for α-amylase,p-nitrophenyl maltopentaoside as substrate for β-amylase, andp-nitrophenylglucopyranoside as substrate for α-glucosidase. The values obtained from tubers stored at 4°C were higher than those from tubers stored at 10°C, the differences being much less in Brodick than in the other three cultivars.

Several clones from a potato breeding programme at the Scottish Crop Research Institute (SCRI) produced acceptable (pale) coloured fry products after five months' storage at 4°C. Chemical analysis of tuber samples taken at five-week intervals during storage at 4°C and 10°C gave a substantial variation in glucose, fructose and sucrose concentrations among the 22 clones examined. Several unnamed SCRI clones showed little accumulation of reducing sugars when stored at 4°C. In marked contrast, the cultivars Record and Pentland Dell, currently the most widely used cultivars for fry processing in the UK, accumulated far greater levels of sugar during low temperature storage. Glucose concentration proved more important than fructose concentration in determining fry colour. Clones with the lowest concentrations of glucose after storage at 4°C also showed lowest concentrations when stored at 10°C. These results are in agreement with previous reports on the predictive value of glucose levels at harvest, but this is the first identification of such low temperature, low sweetening variants in agronomically adapted clones of the cultivated tetraploid potato.

The gut inhabiting bacterium Oxalobacter formigenes may be a negative risk factor in recurrent calcium oxalate kidney stone disease that apparently maintains oxalic acid homeostasis in its host via the degradation of dietary oxalate. The possibility of using this bacterium as probiotic treatment to reduce urinary oxalate was investigated in a rat model.Male Sprague-Dawley rats were placed on a diet supplemented with ammonium oxalate to induce a state of severe hyperoxaluria. Subgroups of these rats received an esophageal gavage of 1 x 10(3), 10(5), 10(7) or 10(9) O. formigenes per feeding for a 2-week period. Each rat was followed for general health and changes in urinary oxalate.Rats with chronic hyperoxaluria resulting from high dietary oxalate that were treated with O. formigenes showed decreased urinary oxalate within 2 days of initiating probiotic supplementation. The amount of the decrease in a 2-week period proved directly proportional to the dose of bacteria. Urinary oxalate in rats receiving higher amounts of O. formigenes returned to almost normal. Throughout the study the rats remained healthy with no signs of toxicity, antibody development or a histopathological condition.Probiotic treatment of hyperoxaluric rats with O. formigenes may significantly and rapidly reduce the level of oxalate in the urine. This probiotic treatment appears to be safe and well tolerated. The approach may be feasible for treating calcium oxalate kidney stone disease.

The countries of Peru, Bolivia, Ecuador and Chile in South America, were the modern countries that occupied the major geographic areas in the Inca Empire. They incorporate all of the extremes of the world’s climatic conditions from the steaming jungles of the Amazon basin to the frigid arctic climates of the high Andean ranges, many of which have permanent snow and an average daily temperature of 0 °C. The western limits border the Pacific Ocean with a meeting of the sixty mile wide Humboldt current hugging the coast from Antarctica to Punto Parinas where it mixes with the warm Equatorial current to form one of the richest ocean fauna in the world. Unfortunately the coastal shore is cut by a series of short rivers running east to west that in many cases only have water a few months out of the year. This results in a narrow strip of coastal desert extending for about 3,000 km along the coast from Tumbes in Peru to Copiapo in Chile, that varies in width from a few kilometers to perhaps 200 at the widest part. The best known geographic area is the Atacama Desert, one of the driest spots on earth. This coastal strip is backed by two to three chains of very high mountains in which peaks reach a height well over 6,000 m, the highest Aconcagua is 6,690 m.

This paper describes the signs of toxicity when seed-bearing flatpea (Lathyrus sylvestris L) hay is fed to sheep. Signs of intoxication (including seizure, muscular trembling and spasmotic torticollis) are similar to those observed for ammonia toxicity in ruminants. Accumulation of ammonia may be a direct consequence of flatpea ingestion, given that 2,4-diaminobutyric acid (DABA, a toxic constituent of flatpea) is known to inhibit hepatic urea synthesis. However, other modes of toxicity for DABA as well as other flatpea toxins may also contribute to this process of intoxication. Our evidence suggests that ruminal microbes are responsible for flatpea detoxification and host animal protection. The adaptation of sheep to flatpea may be a consequence of enhanced ruminal detoxification activity. Ruminal protective functions can be disrupted, however, through abrupt monensin feeding or the replacement of nonadapted for adapted rumen contents. This disruption temporarily suppresses mechanisms of ruminal detoxification. As a consequence sheep can again be made vulnerable to flatpea intoxication.

Samples of the mucosal surface of the caecum and sigmoid colon were obtained from 33 colonoscopy subjects for microbiol studies using a microbiology brush system. Faecal samples and caecal lumen aspirates were also obtained. Estimated numbers of digoxin-reducing, oxalate-degrading and total anaerobic bacteria from the caecal brush samples correlated significantly with the respective concentrations of these organisms from the sigmoid area. The concentrations of oxalate-degrading bacteria and total anaerobes, but not those of digoxin-reducing organisms, were greater in the caecum than in the sigmoid colon. Eight of 23 subjects given an oral dose of digoxin excreted reduced metabolites of digoxin in the urine; high concentrations of digoxin-reducing bacteria were found in caecal and sigmoid samples from each of them. Equally high concentrations or such bacteria were found in caecal and sigmoid specimens from six subjects who did not metabolize digoxin in vivo . Caccal brush concentrations of digoxin-reducing and oxalate-degrading organisms correlated significantly with the concentrations of these bacteria in faeces. The predominant genera of bacteria cultured from caecal and sigmoid brush specimens appeared to be similar. Mean molar percentage distributions of short-chain fatty acids were similar in the caecal aspirates and stool samples. Keywords: Digoxin-reducing bacteria; Oxalate-degrading bacteria; Anaerobic bacteria; Colon; Short-chain fatty acids.

We had proposed earlier that the anaerobe Oxalobacter formigenes sustains a proton-motive force by exploiting a secondary carrier rather than a primary proton pump. In this view, a carrier protein would catalyze the exchange of extracellular oxalate, a divalent anion, and intracellular formate, the monovalent product of oxalate decarboxylation. Such an electrogenic exchange develops an internally negative membrane potential, and since the decarboxylation reaction consumes an internal proton, the combined activity of the carrier and the soluble decarboxylase would constitute an "indirect" proton pump with a stoichiometry of 1H+ per turnover. This model is now verified by identification and purification of OxlT, the protein responsible for the anion exchange reaction. Membranes of O. formigenes were solubilized at pH 7 with 1.25% octyl glucoside in 20 mM 3-(N-morpholino)propanesulfonic acid/K, in the presence of 0.4% Escherichia coli phospholipids and with 20% glucerol present as the osmolyte stabilant. Rapid methods for reconstitution were developed to monitor the distribution of OxlT during biochemical fractionation, allowing its purification by sequential anion and cation exchange chromatography. OxlT proved to be a single hydrophobic polypeptide, of 38 kDa mobility during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with a turnover number estimated as at least 1000/s. The properties of OxlT point to an indirect proton pump as the mechanism by which a proton-motive force arises in O. formigenes, and one may reasonably argue that indirect proton pumps take part in bacterial events such as acetogenesis, malolactate fermentation, and perhaps methanogenesis.

Tooth mutilation or adornment in ancient Peru and Chile is discussed as well as that seen in present day Nigeria. Dental mutilation must be recognized (diagnosed) for what it is and discouraged in order to prevent dentoalveolar pathology and tooth loss.

Determinations of hot water extract values of malts of some modern barleys and their parental cultivars correlated well (r = −0.71) with milling energy estimates made on ungerminated grain. This confirms previous findings that these grain attributes are negatively correlated over different sites and growing seasons. Three types of barley endosperm can be distinguished on the basis of milling energy determinations. Most barley cultivars that are difficult to malt or are classified as feed barleys have high milling energy values (ranging from 370 to > 400 mg trace weight). This includes a number of currently recommended cultivars with Hordeum laevitigum in their pedigree. A second endosperm type has significantly lower milling energy values than the feed barley group (ranging from 330 to 355 mg, trace weight); barleys in this category also produce malts with high hot water extract values, e.g. Wing, Proctor and Berac. All of these barleys have one of the sister lines, Kenia—Opal—Maja in their ancestry. The third endosperm type with a loosely-structured ‘mealy’ endosperm has very low milling energy values (280 to 315 mg, trace weight) and includes the cultivars Ark Royal, Triumph and Keg, which give very high hot water extracts from their malts. All of the barleys in this group have the European malting barley Kneifel (also with a very low milling energy) in their pedigree. The results strongly indicate that hot water extract values of malts of current European cultivars are mainly due to the milling energy attribute of the endosperm, or are closely linked to it. This endosperm attribute has been selected through pedigree crossing or in barley collections, from just a few older malting quality cultivars. Evidence that this attribute is not linked to Hordein protein patterns controlled by the hor 1 and hor 2 loci on chromosome 5, is also presented.

In the Gram-negative anaerobe, Oxalobacter formigenes, the generation of metabolic energy depends on the transport and decarboxylation of oxalate. We have now used assays of reconstitution to study the movements of oxalate and to characterize the exchange of oxalate with formate, its immediate metabolic derivative. Membranes of O. formigenes were solubilized with octyl-beta-D-glucopyranoside in the presence of 20% glycerol and Escherichia coli phospholipid, and detergent extracts were reconstituted by detergent dilution. [14C]Oxalate was taken up by proteoliposomes loaded with unlabeled oxalate, but not by similarly loaded liposomes or by proteoliposomes containing sulfate in place of oxalate. Oxalate transport did not depend on the presence of sodium or potassium, nor was it affected by valinomycin (1 microM), nigericin (1 microM), or a proton conductor, carbonylcyanide-p-trifluoromethoxyphenylhydrazone (5 microM) when potassium was at equal concentration on either side of the membrane. Such data suggest the presence of an overall neutral oxalate self-exchange, independent of common cations or anions. Kinetic analysis of the reaction in proteoliposomes gave a Michaelis constant (Kt) for oxalate transport of 0.24 mM and a maximal velocity (Vmax) of 99 mumol/min/mg of protein. A direct exchange of oxalate and formate was indicated by the observations that formate inhibited oxalate transport and that delayed addition of formate released [14C]oxalate accumulated during oxalate exchange. Moreover, [14C]formate was taken up by oxalate-loaded proteoliposomes (but not liposomes), and this heterologous reaction could be blocked by external oxalate. Further studies, using formate-loaded proteoliposomes, suggested that the heterologous exchange was electrogenic. Thus, for assays in which N-methylglucamine served as both internal and external cation, formate-loaded particles took up oxalate at a rate of 2.4 mumol/min/mg of protein. When external or internal N-methylglucamine was replaced by potassium in the presence of valinomycin, there was, respectively, a 7-fold stimulation or an 8-fold inhibition of oxalate accumulation, demonstrating that net negative charge moved in parallel with oxalate during the heterologous exchange. The work summarized here suggests the presence of an unusually rapid and electrogenic oxalate2-:formate1- antiport in membranes of O. formigenes. Since a proton is consumed during the intracellular decarboxylation that converts oxalate into formate plus CO2, antiport of oxalate and formate would play a central role in a biochemical cycle consisting of (a) oxalate influx, (b) oxalate decarboxylation, and (c) formate efflux.(ABSTRACT TRUNCATED AT 400 WORDS)

Approximately half the total α-amylase and phosphorylase activity detectable in crude homogenates of the tissues of developing barley grain was localized in the pericarp. This tissue is particularly active in the early stages of grain development. It is suggested that this activity may influence the starch type and content of the mature barley grain.

SUMMARYVascular and non-vascular cell walls were isolated separately from leaves, upper stems and lower stems of 12 kale (Brassica oleracea L.) cultivars, by a sieving technique. The digestible organic matter in the dry matter (DOMD) of the cell walls and of the whole plants was determined by pepsin-cellulase digestion. The measured whole-plant DOMD correlated closely with the DOMD predicted by adding together the amounts of non-digested material derived from all the plant's component cell-wall fractions. Differences in DOMD between cultivars were determined primarily by the amount of vascular cell walls in the stems, particularly the lower stems; that is, by the stem anatomy. The vascular cell walls of the upper stems had a wider range of DOMD values and a higher mean DOMD than the vascular cell walls of the lower stems. Thus cell-wall composition made some contribution to determining the whole-plant DOMD, although it contributed less than the anatomy of the stem.

A reversed-phase high performance liquid chromatography (RP-HPLC) system was used to separate the storage proteins (hordeins) extracted from European barley cultivars. From a total of 38 barleys tested, 26 types of hordein patterns could be distinguished after RP-HPLC. This appears to be a marked improvement in resolution over that achieved in a similar survey of European barley cultivars using SDS polyacrylamide electrophoresis (32 hordein patterns resolved by SDS PAGE from a total of 160 spring and winter barleys tested). Different hordein patterns were resolved by RP-HPLC within each of two groups of barley previously classified by SDS PAGE as indistinguishable within groups (three distinct patterns identified in a total of five cultivars tested from group 1A and five patterns observed among eight cultivars from group 3B). Thus RP-HPLC achieves a higher resolution than undirectional electrophoresis and promises to be a valuable aid in the identification of European barley cultivars.

Determinations of milling energy, nitrogen, acid-soluble beta glucan and malt extract after micromalting, were made on grain samples of twenty nine barley cultivars. In addition the flour from unmalted grains was scanned over the near infra-red spectrum, and the scan data were subjected to a principal components analysis (PC). Predicted malt extract values resulting from an NIR multiple regression equation with PC terms, correlated well (r = 0.934) with the manual extract values. This confirms previous evidence that malt extract value depends largely on constituents in the resting grain, rather than on malt enzymes. An attempt to locate NIR absorptions relating to malting quality was made by restructuring the NIR spectrum of the samples according to the weightings modified by the regression coefficients in the PC regression equation for hot water extract value. The spectrum reconstructed in this way showed a number of absorption peaks and troughs. From comparison with previous NIR scans it was concluded that a strong peak at the wavelength 2100 nm was due to a starch absorption and this together with minor starch overtone peaks correlated positively with malt extract. Troughs at 2180 nm, 1980 nm and 1700 nm indicated a negative association between malt extract and some proteins. There were also wide troughs at 1830 and 2330 nm indicating a negative relationship between malt extract and beta glucan. Other peaks and troughs in the reconstructed spectrum could not readily be assigned to a constituent. A reconstructed protein spectrum consisted of peaks and troughs that agreed with previous assignations for protein absorbancies. A milling energy reconstruction was approximately the inverse of the malt extract spectrum, and an acid-soluble beta glucan reconstruction was relatively featureless and appeared to be due to the effects of particle size variations.

A β-amylase polymorphism (electrophoretic forms Sd1 and Sd2) in barley malt is shown to be closely associated with the proportion of free to total (free plus latent) β-amylase, but not with the level of total β-amylase in the mature grains of 46 cultivars. All of the cultivars with Sd1 malts have a proportion of free β-amylase less than 50% (usually from 30% to 40%) of total whereas Sd2 types have free to total β-amylase (F/T) ratios greater than 50% (usually between 62% and 78%). These polymorphisms are also correlated with forms of β-amylase in the developing grain, although, in the latter, Sd1 cultivars can be divided into two types, Sdd and Sde which cannot be distinguished either in malts or on the basis of F/T ratio. Unusual F/T ratios of an intermediate type (approximately 50%) and a very low type (under 30%) also occurred in these experiments. These may result from environmental effects or may be new genetic types.

The quantity and character of the microbial lipid isolated from rumen digesta are interpreted as indicating that significant quantities of milk fat acids originate from rumen microbial synthesis of long chain acids from volatile fatty acids. Component fatty acid patterns are presented of rumen bacterial lipid, crude rumen protozoal lipid, blood serum lipid, and milk lipid isolated from samples taken from a lactating Holstein. Certain rumen bacterial lipid fractions are shown to be very rich sources of odd carbon acids and branched acids, and it is suggested that the major source of these acids in ruminant fats is from bacterial synthesis rather than animal synthesis.

Transfer of radioactive carbon from rumen gases to blood, milk, and saliva was studied in sheep and goats following intraruminal insufflation of C14O2 and C14H4. In four sheep allowed to inspire eructated gas, radioactive carbon was detected in blood from the carotid artery 4–5 sec after the first rumen eructation contraction following C14O2 insufflation. In one sheep and one goat, which were not allowed to inhale eructated gas, there was eventual absorption of radioactive carbon from the digestive tract, but at a much lower level and without the marked fluctuations. In three sheep radioactivity gradually increased in the saliva samples until it was more than double that of blood samples collected simultaneously. In one lactating goat (two experiments) dissolved C14O2 appeared in milk within 3 min following the first eructation and reached maximum values within 15 min. Radioactivity was present in milk solids, primarily in the lactose fraction, 20 min after intraruminal insufflation of C14O2. In one sheep and two goats radioactivity in blood resulting from C14H4 insufflation was much less than after intraruminal insufflation of C14O2.

From genetic studies on two β-amylase forms (Sd1 and Sd2) observed in barley malts it is concluded that the Sd1 and Sd2 phenotypes are controlled by a pair of alleles acting without dominance. Gene dosage effects typical of characters determined by the endosperm were observed in F1 hybrids, Preliminary studies on the distribution of Sd1 and Sd2 forms indicate that Sd1 is the rarer one; of thirty-one cultivars tested, twenty were Sd2, nine were typed as Sd1 and two cultivars had both Sd1 and Sd2 phenotypes. An analysis of joint segregations for Sd1, Sd2, the heat-stable α-amylases and two esterase forms gave no evidence for linkage between these three loci.

A modification of Briggs' starch/agar α-amylase assay is described which enables total diastatic activity to be measured. This has been used to differentiate between a high diastase barley variety (Olli, green malt DP over 300° L) and a normal variety (Ymer, green malt DP approximately 120° L), although replication of measurements is shown to be necessary. The assay has been used in selection experiments, where a significant response to selection for increased “halo size” was obtained in one generation of selection. In addition, there were significant differences between the selected populations in ability to germinate, a character for which no conscious selection had been applied. The assay is of potential use in plant breeding as an aid to selection for diastatic power.

A new apparatus for the rapid measurement of energy required to mill barley is described. This ‘Comparamill’ consists of a flywheel connected to a microhammer mill in such a way that the flywheel drives the hammers during milling, and several milling operations have been automated. When grain samples of currently used varieties grown in small field plots were compared, hot water extracts made of micromalted samples correlated (r = −0·59) with milling energy measurements on resting grains. The results also demonstrate an environmental effect on malting performance and milling energy. Samples of certain varieties with unusual grain nitrogen contents did not malt in accordance with NIAB recommended list gradings. Furthermore samples of the variety, Mazurka grown in a particular environment were an exception to the correlation between milling energy and extract. This correlation improves (r = − 0·76) if all of the Mazurka samples are omitted.

Estimates of grain hardness from measurements of milling energy were made on four hundred and eighty barley cultivars. The same cultivars were also subjected to an infra-red analysis used to predict soluble β-glucan and nitrogen contents. The results demonstrated variation for these endosperm characters, with eighteen cultivars having a lower milling energy, and more than a hundred cultivars with a lower soluble β-glucan content than Gerkra, a barley with good malting quality. Of these, nine cultivars were lower for both characteristics. Information about this variation is, therefore, potentially useful when breeding for malting quality.

It has previously been reported that the malting quality of barley is related to the amount of β-glucan dissolved at low pH under defined conditions. An infra red reflectance instrument, the ‘InfraAlyzer’, can be used to estimate this ‘acid-soluble’ β-glucan content of barley. This is a rapid test (approximately one min/sample) and is therefore suitable when screening for low soluble β-glucan in the early generations of malting quality breeding programmes. The relationship between predicted and measured values for soluble β-glucan differs from comparisons made for other quality components in forages, in that it is curvilinear rather than linear. A logarithmic transformation of the soluble β-glucan values, however, allows the current ‘InfraAlyzer’, which produces linear regressions only, to predict values for soluble β-glucan that correlate well (r = 0.87) with the measured results.

Edotoxin was detected, using the limulus amebocyte lysate (LAL) test, in the blood of 3 sheep and 1 steer which had been experimentally "overfed" (induced grain engorgement) with a mixture of corn and oats (2:1). The 1st postfeeding blood samples were collected 24 hours after overfeeding. In 2 sheep and 1 steer, the 24-hours blood samples were test positive. In 1 sheep which died, the 48-hour blood sample was the 1st test-positive sample. In all cases, pre-overfeeding blood samples were taken just before overfeeding.

Understanding of ruminant digestive function has improved tremendously over the past 25 yr. This progress, viewed in retrospect, has clearly led to improvements in animal production. The encouraging aspect of this is that these improvements were made through qualitative application of our knowledge. Quantitative application of this knowledge-a major emphasis in current efforts--will likely yield even greater benefits in the future. Although we continue to identify new rumen microbes, it is suggested that the major rumen microbes have been identified. The nutritional requirements, physiological characteristics, biochemical pathways and functions of these microbes have been largely characterized. Major strides have been made toward understanding the complex interactions among rumen microbes that characterize the rumen ecosystem; microbes interact to improve the digestion of complex carbohydrates, such as cellulose, beyond the extent individual species can achieve; microbes provide nutrients required for the growth of other microbes and microbes remove products inhibitory to other microbes usually to their mutual benefit. Considerable progress has been made toward development of quantitative relationships among the chemical composition of ruminant feeds, dynamic aspects of digestion in the rumen, products of digestion absorbed by the ruminant, and, most important, how these can be manipulated to improve animal productivity.

Samples from the rumen and cecum of cattle and sheep were cultured to determine changes in microbial populations resulting from overfeeding with grain. Before the animals were overfed, the predominant organisms from both sides were those that grew anaerobically on a relatively nonselective ruminal fluid medium and would not grow on selective mediums designed to culture lactobacilli, streptococci, coliforms, or Clostridium perfringens. By 24 hours after overfeeding, lactic acid bacteria had increased in numbers so that they were the most numerous organisms in both the rumen and the cecum. The concentrations of coliforms and C perfringens also increased after overfeeding and were generally higher in the cecum than in the rumen.

Cholesterol may interfere with normal repair processes in the arterial wall. It is also possible that this same action occurs during inflammation and repair throughout the body. This hypothesis was tested by giving intravenous injections of Bacteroides fragilis, a bacterium that is innocuous for normal rabbits even when multiple large doses are given. Almost all cholesterol-fed rabbits developed significant pleuropulmonary infections with complications that included vasculitis, thrombosis, extrapulmonary infections, and significant mortality. More than half of this group was culturally positive for B. fragilis at the time of autopsy while cultures from control animals were sterile. These results suggest that cholesterol may interfere with the functions of those cells involved in host defense.

During enterohepatic circulation conjugated steroids are hydrolyzed by intestinal bacteria, further metabolized mainly by anaerobic bacteria, reabsorbed, reconjugated and delivered to the blood for renal excretion. 21-Dehydroxlylation of tetrahydrodeoxycorticosterone (THCOD) to pregnanolone is performed exclusively by Eubacterium lentum, a normal inhabitant of the intestinal flora. The concentration of E. lentum in feces can be determined from the highest dilution of fresh voided stool capable of 21-dehydroxylating THDOC. Such studies revealed that the concentration increases from 106/g wet feces during the first year of life to 108/g feces in the 7th and 8th decade. Colonization appears to be independent of diet since the organisms are present in babies whether breast-fed or on formula, in subjects on a “Western diet” and in Africans consuming a diet low in meat and fat.