Involvement of dehydroalanine and dehydrobutyrine in the addition of glutathione to nisin

Nisin variants and fragments were reacted with glutathione, and the products of the reactions were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and liquid chromatography/mass spectrometry (LC-MS). Reactions between glutathione and either [Ala5]nisin or [Ala33]nisin resulted in products with two glutathione molecules conjugated to one nisin variant molecule. Only one glutathione molecule was added to [Ala5,Ala33]nisin. Fragmentation of the nisin molecule resulted in nisin 1-12, nisin 1-20, and nisin 1-32 fragments. Each fragment retained two dehydro residues, which subsequently underwent reaction with glutathione. The data indicated that the dehydroalanine residues of nisin are sites of addition for glutathione. Such addition renders the nisin molecule inactive.     

Nutritional utilization by the rat of diets based on lentil (Lens culinaris) seed meal or its fractions

The nutritional effects in the rat of raw lentil meal or its fractions have been evaluated in three feeding trials. Growth, gain/feed ratio, apparent N digestibility, and N retention were significantly (p < 0.05) reduced by the inclusion of whole lentil meal, dehulled lentil meal, or ethanol-extracted lentil meal as the sole source of protein in the diet. Pure lentil lectin and lectin-depleted albumin proteins had no significant negative effect on nutritional performance. In contrast, growth, gain/feed ratio, protein conversion efficiency, N digestibility, and N retention were significantly (p < 0.05) reduced by diets containing lentil globulins or lentil hulls. The poor nutritional quality of raw lentil meal for rats is therefore likely to be primarily due to the combined effects of these two components.     

Modeling First Break Milling of Debranned Wheat Using the Double Normalized Kumaraswamy Breakage Function

Debranning of wheat affects flour quality, initially by altering the breakage of wheat kernels during first break. The double normalized Kumaraswamy breakage function was applied to model the effect of debranning on wheat breakage during first break milling, in which type 1 breakage describes a relatively narrow distribution of midsized particles, whereas type 2 breakage describes a wide size range of predominantly small particles extending to very large particles. Mallacca (hard) and Consort (soft) wheats were debranned and milled at three roll gaps under sharp‐to‐sharp and dull‐to‐dull dispositions. Type 1 breakage increased at longer debranning times, whereas type 2 breakage decreased, for both wheat varieties under both dispositions. Sharp‐to‐sharp milling tended to produce more type 1 breakage than dull‐to‐dull. A mechanism of wheat breakage is proposed to explain the coproduction of very large and small particles via type 2 breakage and, hence, the effect of debranning. The proposed mechanism is that small particles of endosperm arise from scraping of large flat particles of wheat bran under the differential action of the rolls, such that removal of the bran reduces the production of the large bran particles and thus reduces the opportunity for the scraping mechanism that produces the very small particles.     

Standardized exercise test and daily heart rate responses of thoroughbreds undergoing conventional race training and detraining

Ten healthy sedentary male Thoroughbreds with previous race training experience were studied for 14 weeks. Horses were trained for 9 weeks, using a program designed after those used commonly in the United States. Horses were trained conventionally by slow trotting (250 m/min) for 2 weeks and galloping (390 to 450 m/min) for 4 weeks, followed by 3 weeks of galloping (440 to 480 m/min) and intermittent sprinting exercises (breezes) at distances between 600 and 1,000 m (900 to 950 m/min). The horses were then pasture rested for 5 weeks. A standardized exercise test (SET) involving an 800-m gallop at 800 m/min was administered before and after the 9-week training period and after the 5-week detraining period. Heart rate (HR) was monitored during exercise and at standardized intervals after exercise for 60 minutes. Venous blood for determination of plasma lactate concentration was obtained at 5 minutes after exercise. Heart rate was monitored daily at rest, during exercise, and through the first 60 minutes of recovery. Venous plasma samples (for lactate determination) were obtained 5 minutes after the sprinting exercises. Horses were observed daily before exercise for signs of lameness and were not allowed to train if lame. Differences after 9 weeks' training were seen in the SET recovery HR at 0.5 through 5 minutes after exercise (P less than 0.05 to P less than 0.01). Differences after detraining were seen in the SET recovery HR at 40 and 60 minutes after exercise (P less than 0.05 to P less than 0.01). Neither training nor detraining resulted in differences in plasma lactate concentration after the SET gallop.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phenylbutazone inhibition of equine platelet function.

Nonsteroidal anti-inflammatory drugs impair platelet aggregation and secretion in man, pigs, and rabbits and inhibit platelet thromboxane/prostaglandin synthesis. The present investigation studied the effects of phenylbutazone on platelet aggregation and bleeding times in the horse. Aggregation responses to adenosine diphosphate and collagen were markedly impaired 15 minutes and 2 hours after treatment, but 4 hours after treatment, platelet responses approximated those prior to treatment. The in vivo effect of phenylbutazone correlated with its plasma concentrations. Phenylbutazone, like aspirin, appeared to exert its effect by inhibiting thromboxane/prostaglandin synthesis, because thrombin-induced malondialdehyde formation was inhibited. However, unlike aspirin, free arachidonate-induced malondialdehyde synthesis was reduced but not eliminated, which suggested that phenylbutazone may have more than one site of action. Although collagen-induced platelet aggregation was impaired, a response was still present, and bleeding times were not altered by phenylbutazone treatment. To account for these findings, it is proposed that equine platelets can respond to collagen by thromboxane/prostaglandin independent pathways. The physiologic and pathophysiologic importance of these findings is discussed.     

Effects of Feeding Time and Frequency on Growth of Channel Catfish Ictalurus punctatus in Closed Recirculating Raceway Systems

Abstract.– Experiments were conducted to evaluate the effects of feeding time and frequency on the growth, survival, feed conversion, and body composition of channel catfish Ictalurus punctatus cultured in closed recirculating raceway systems. In separate experiments, two stocking sizes (18 and 232 g/fish) of channel catfish were examined. Treatments consisted of 1) feeding catfish once daily, 3% of body weight at 0800 h; 2) feeding catfish once daily, 3% of body weight at 1200 h; 3) feeding catfish once daily, 3% of body weight at 1700 h; and 4) feeding catfish three times daily, 1% of body weight at 0800 h, 1200 h, and 1700 h. Weight gain, specific growth, feed conversion, percentage survival, and fillet proximate composition of channel catfish among treatments did not differ ( P > 0.05). The percentage visceral fat of channel catfish fed the single meal at 0800 h was significantly lower (P < 0.05) than channel catfish receiving multiple feedings, but was not different than the visceral fat content of channel catfish fed at 1200 h and 1700 h. Under the conditions of this study, results indicate neither feeding time or feeding frequency significantly influences the growth, survival, and body composition of channel catfish raised in closed recirculating raceway systems.     

Arterial blood gas tension and acid base balance during exercise in horses with pharyngeal lymphoid hyperplasia

Arterial blood gas and acid-base values during maximal exercise over a 1.2 km distance were recorded in four Thoroughbred horses before and after the chemical induction of pharyngeal lymphoid hyperplasia (PLH). Samples were collected after galloping 0.8 km and 1.2 km, immediately upon stopping and 5 mins after exercising. In only one horse was any difference noted in the pre and post PLH induction results. The horse was more hypercapnoeic at the 1.2 km mark and also took much longer to complete the gallop when it had PLH. However, it also had signs of lower respiratory disease. In the other horses, the only changes which could be attributed to PLH were seen immediately upon stopping. It seems that PLH does not inhibit gas exchange during exercise unless the lesions are extremely severe.