Great progress in the study on chemically defined diet and amino acid nutrition of Nilaparvatalu gens

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Effect of local methods of preparation on the amino acid constituents of broad beans

Dried broad beans (Giza 1) were subjected to the different methods of preparation that are commonly used in Egypt. These methods include: 1) Germination, 2) Germination and boiling, which is the method commonly used to make ‘Nabet Soup’ and 3) Stewing, to make ‘Medammes’ the popular breakfast dish in Egypt and Middle East. Paper chromatography was used for the separation and identification of different amino acids in both dried and prepared broad beans. The amino acid analysis data were subjected to analysis of variance, and the t-test was applied to contrasts of different amino acids. The results indicated the presence of 17 amino acids in the hydrolyzates of both raw and germinated seeds. These amino acids were determined quantitatively except proline. It was clear from the results that cystine was destroyed completely by either boiling or stewing. The only amino acids that showed significant loss by germination were aspartic acid and alanine. Both boiling of the germinated seeds, and stewing caused significant loss in the amino acids lysine, arginine, aspartic aced, alanine, methionine and tryptophan. The higher temperature that was used in boiling the germinated seeds was found to have more destroying effect on some amino acids than stewing. The amino acids scores showed the sulfur containing amino acids to be the first limiting amino acid in both hard and prepared broad beans.     

Effects of various processing methods on free and bound amino acid contents of potatoes

The effects of various processing methods on available lysine and total and free amino acid levels of low (1.065 – 1.075) specific gravity (LSG) and high (1.095 – 1.106) specific gravity (HSG) potatoes were investigated. LSG potatoes after canning and chip making showed approximately 40% loss of total amino acid contents. Such losses in drum dried potatoes were approximately 20% and that of french fries 4.5%. All processing methods adversely affected the available lysine content; chips and canned potatoes showing the maximum loss, followed by drum dried and french fried potatoes. Losses in HSG potato products showed a trend similar to that of LSG material, but on a considerably reduced scale.     

Influence of dietary soybean trypsin inhibitors and DL-ethionine on sulfur amino acid adequacy of diets for young rats

Weanling male Wistar rats were fed 20% protein diets based on casein or either of two combinations of soy protein isolate and ground raw soy providing three levels of soybean trypsin inhibitors (SBTI; 0,448 and 808 mg of trypsin inhibited per 100g of diet respectively). DL-ethionine was included at three levels (0,0.05% and 0.10%) with each level of SBTI. After 4, 8 and 12 weeks ofad libitum feeding, diets containing SBTI without DL-ethionine were associated with decreases in weight gain, feed efficiency, serum cholesterol and serum urea nitrogen. Higher levels of triglycerides, glutamate pyruvate transaminase (SGPT) and altered serum free amino acid levels were also found. Increased dietary levels of DL-ethionine also resulted in deficits in growth and feed efficiency, decreased serum cholesterol, increased SGPT and similar alterations in serum free amino acids. Combination of dietary SBTI with DL-ethionine resulted in even greater growth deficits and serum cholesterol decreases as well as increases in SGPT and serum triglycerides and changes in serum free amino acid levels. Methionine deficiency in the young rats fed SBTI and DL-ethionine was indicated by the changes in serum amino acids and growth deficits. Moderation of some effects over the 12 week test period suggested decreased methionine requirements in the older rats.     

Fertilizer effects on yield,mineral and amino acid composition,dietary fibre content and nutritive value of leeks

In pot experiments with greatly differing rates of N, P, S, K and Ca, dry matter (DM) yields of leek stems varied from 25 to 164 g/pot. Total-N and NO₃-N concentrations varied from 1.18 to 3.56% and from 10 to 1515 ppm in DM, respectively. Both N applications and P and K deficiency greatly increased total-N and NO₃-N content. S applications increased total-S content from 0.047 to 0.359% in DM, of which between approximately 100 to 25% were found in methionine+cystine. Total-N/total-S ratios decreased from 57 to 6 with the highest S level. P and K applications increased their respective content in DM two- and threefold. Severe Ca deficiency reduced Ca content from 0.495 to 0.045%. Iron, zinc, manganese and copper contents varied from 33–69, 14–26, 11–34 and 3.1–5.7 ppm in DM, respectively. Increasing N contents, whether due to N applications or P or K deficiency, decreased the content of all essential and some other amino acids in crude protein. Both S and severe P deficiency had a pronounced negative effect on amino acid composition and chemical score. Only glutamic acid (glutamine) and arginine were increased by increasing N contents. However, expressed as g/kg DM the concentrations of all amino acids were positively correlated with protein content. S and P deficiency reduced total dietary fibre (TDF) content of DM from 28.3 to 18.6% and 17.4%, respectively, of which between 53 and 60% were insoluble dietary fibre (IDF). Digestible energy (DE) was positively correlated with protein content (r=0.90**). In N-balance trials with rats, increasing protein concentrations (50% of total protein given as casein and supplemented with 1% methionine) raised the true digestibility (TD) of the protein from 44 to 72%. The biological value (BV) of protein was generally high, with a mean of 91.7 N deficiency tended to increase and S deficiency tended to decrease the BV.     

Effect of formic acid and a bacterial inoculant on the amino acid composition of grass silage and on animal performance

An Italian ryegrass and hybrid ryegrass sward was harvested on 11 May 1994. The mean dry‐matter (DM) content of the herbage was 197 g kg^–1 fresh matter (FM), and mean nitrogen and water‐soluble carbohydrate contents were 20 and 272 g kg^–1 DM respectively. Approximately 72% of total nitrogen (TN) was in the form of protein‐nitrogen. The herbage was treated with either no additive, formic acid (3·3 l t^–1) (Add‐F, BP) or inoculant (2·3 l t^–1) (Live‐system, Genus) and ensiled in 100 t silos. Changes in effluent composition with time showed that silage fermentation and protein breakdown were delayed by treatment with formic acid. Formic acid and inoculant treatments also inhibited amino acid catabolism during ensilage. All silages were well fermented at opening with pH values < 4·0 and ammonia‐N concentrations of ≤ 50 g kg^–1 TN after 120 d ensilage. Treatment had an effect on protein breakdown as measured by free amino acid concentration, with values of 21·5, 18·2 and 13·2 mol kg^–1 N at opening (191 d) for untreated, formic acid‐treated and inoculated silages respectively. Amino acid catabolism occurred to the greatest extent in untreated silages with significant decreases in glutamic acid, lysine and arginine, and increases in gamma amino butyric acid and ornithine. The silages were offered ad libitum without concentrate supplementation to thirty‐six Charolais beef steers for a period of 69 d (mean live weight 401 kg). Silage dry‐matter intakes and liveweight gains were significantly (P < 0·05) higher on the treated silages. Silage dry‐matter intakes were 7·42, 8·41 and 8·23 kg d^–1 (s.e.d. 0·27) with liveweight gains of 0·66, 0·94 and 0·89 kg d^–1 (s.e.d. 0·058) for untreated, formic acid‐treated and inoculated silage‐fed cattle respectively. In conclusion, additives increased the intake of silage and liveweight gain by the beef steers, and it is suggested that this may be caused in part by the amino acid balance in these silages.     

The effect of nitrogen fertilization on the amino acid composition and nutritive value of cereals

A range of samples embracing 14 varieties from different localities within the United Kingdom, many grown with the application of different known levels of nitrogenous fertilizer, were submitted to proximate analysis, some analysed for total amino acid composition and some evaluated nutritionally in near-practical dietary mixtures with various protein concentrates.Location of growth was found to be more important than level of nitrogen application in determining the protein content of the harvested grain. Small differences in amino acid composition were noted, and there appeared to be a progressive decline in lysine content with increasing nitrogen level in the seed.Significant differences in nutritive value between the barleys were detectable in mixtures of each with protein concentrates, and in general discrimination between them was better if the accompanying concentrate was of poor quality e.g. groundnut. With fish meal differences between the barleys were well marked. The differences found were real and reproducible, and the results indicated that particular barleys differed in their ability to complement soya bean or groundnut.

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Zusammenfassung Es wurden Proben von 14 Getreidesorten untersucht, von verschiedenen Standorten Großbritanniens, die zumeist mit verschieden hohen Stickstoffgaben gedüngt waren. Die Untersuchung der Proben bezog sich teils auf die Gesamt-Aminosäuren und teils auf den ernährungsphysiologischen Wert der Proben in praxisnahen Diät-Mischungen mit verschiedenen Protein-Konzentraten.Der Protein-Gehalt des geernteten Getreides ist stärker vom Standort abhängig als von der Höhe der Stickstoffdüngung. Es wurden geringe Unterschiede in der Aminosäuren-Zusammensetzung festgestellt, und es scheint, daß bei fortschreitender Zunahme des Stickstoffgehaltes in den Getreidekörnern der Lysingehalt abnimmt.Signifikante Unterschiede im ernährungsphysiologischen Wert verschiedener Gerstensorten waren in Mischungen jeder einzelnen mit Proteinkonzentraten nachweisbar, wobei die Unterschiede im allgemeinen deutlicher wurden, wenn die zugemischten Konzentrate von geringerer Qualität waren, z.B. Erdnuß. Mit Fischmehl versetzt traten die Unterschiede zwischen den Gerstensorten weniger deutlich hervor. Die gefundenen Werte waren reproduzierbar, und die Ergebnisse weisen darauf hin, daß insbesondere die Gerstensorten, in ihrem Ergänzungswert für Sojabohne oder Erdnuß differieren.

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Résumé 14 lots de céréales, provenant de diverses stations de Grande Bretagne, et soumis à des taux différents de fumures azotées, ont été étudiés. Chaque lot était analysé au point de vue du taux d'aminoacides, et au point de vue nutritionnel, dans des mélanges analogues à ceux de la pratique, à des taux protéiques variés.Le taux de protéines d'une céréale dépend davantage de la station, que du taux de fumure. De faibles différences dans les taux d'aminoacides ont été observés; il semble que le taux de lysine décroisse lorsque croit le taux d'azote du grain.Des différences significatives dans la valeur nutritionnelle de diverses variétés d'orges apparurent, dans des mélanges de ces variétés avec des concentrés de protéines, ces différences étaient plus nettes avec des concentrés de plus médiocre qualité, par exemple formé de tourteau d'arachide. Les formés de poison ne furent pas apparaitre aussi nettement les différences parmi diverses qualité d'orges. Les résultats sont bien reproductibles, la conclusion en est que les variétés d'orges n'ont pas toute la même valeur comme supplément du tourteau de soya ou d'arachide.

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Paper presented at the conference of the International Association for Quality Research on Food Plants (CIQ) held in common with the Deutsche Gesellschaft für Qualitätsforschung (Pflanzliche Nahrungsmittel) e.V. (DGQ) in Berlin on 6th October 1972.     

Some investigations on the pectin and amino acid composition of Dovyalis caffra W. fruit

Pectin was found in the fruits ofDovyalis caffra W. (3.7%). Acid hydrolysis of the isolated pectin material afforded galacturonic acid (63%), galactose (26.8%), arabinose (2.13%), xylose (1.42%), and rhamnose (0.3%). With sugar and acid, pectin gave a gel of 100-grade. The fruits were shown to contain 15 combined amino acids. Glutamic acid, aspartic acid, and leucine comprised 28.25, 13.56, and 10.60% of the total amino acid content, respectively.     

Variations in the dietary cation–anion difference and the acid–base balance of dairy cows on a pasture-based diet in south-eastern Australia

The variation in the dietary cation–anion difference (DCAD) and the urinary pH of dairy cows was examined over the year 1996–97 in Victoria, south-eastern Australia. Mineral concentrations in the pasture and dairy cow milk production were also examined. Three farmlets (A, B and C) under different feeding and management systems were used for the purpose of the study. Feeding management was based on grazed grass with stocking rates of 1·4, 2·5 and 4·7 cows ha^–1 for farmlets A, B and C respectively. Cows on farmlets B and C received more supplementary feed than those on the A farmlet.
The urine of the cows in each herd was sampled for pH twice monthly, after morning milking. A sample of the feed on offer the previous day was collected and analysed for crude protein, in vitro dry-matter digestibility and macrominerals. Milk yields were recorded on the same day as urine sampling and weather data for the previous day were also collected.
Pasture cation–anion difference was not greatly influenced by stocking rate or associated management practices, although mineral concentrations in pasture did vary. Urine pH was unaffected by changes in climate, management strategies (e.g. stocking rate), season and stage of lactation. Moreover, urine pH was also unaffected by changes in DCAD until the DCAD declined below approximately +15 mequiv. 100 g^–1 for two consecutive sampling periods.
It is concluded that when this threshold for DCAD (+15 mequiv. 100 g^–1) is breached, even in late lactation, a decrease in urine pH occurs. In south-eastern Australia, the DCAD offered to non-lactating cows in the last 2 weeks of pregnancy, in spring-calving herds, on a pasture-based diet is nearly always above that regarded as optimum in other feeding systems.     

Effects of gamma irradiation on mycotoxin disappearance and amino acid contents of corn,wheat, and soybeans with different moisture contents

The effects of gamma irradiation on degradation of aflatoxin B₁ in wheat, corn, and soybeans and of T-2 toxin in wheat, deoxynivalenol (DON) in soybeans, and zearalenone in corn at 9, 13, and 17% moisture were studied. Radiation doses of 5, 7.5, 10 or 20 kGy were applied to spiked grain samples, and the residual toxins were measured using an enzyme linked immunosorbent assay (ELISA). Irradiation doses of up to 20 kGy did not significantly affect aflatoxin B₁ in any of the three grains, but significant reductions occurred in T-2 toxin, DON, and zearalenone concentration at doses of 10 or 20 kGy and in T-2 toxin at the 7.5 kGy dose. Two-way analysis of variance with Tukey's Multiple Range Test showed no significant interaction between radiation dose and grain moisture level. Irradiation of the ground grains at doses higher than 5 kGy resulted in small, but significant, losses of lysine in corn (only at 7.5 kGy), wheat, and soybeans, and methionine was reduced in wheat and corn samples. In some cases, phenylalanine decreased in corn and wheat, and histidine levels in wheat were reduced in samples receiving 7.5 kGy of irradiation. Other essential amino acids were not affected significantly by irradiation.Contribution No. 94-114-J of the Kansas Agricultural Experiment Station.     

A single amino acid substitution in puroindoline b impacts its self-assembly and the formation of heteromeric assemblies with puroindoline a

Puroindolines (PINs) A and B were purified from soft (Paledor) and hard (Recital, Courtot) wheat cultivars. Their purity and heterogeneity due to post-translational processing were characterized by SDS- and acid-PAGE, reversed-phase HPLC and mass spectrometry. By using dynamic light scattering (DLS), asymmetrical flow field-flow fractionation (AF4) and size exclusion chromatography (SEC), we showed that the size distributions of PINA are similar for the three varieties and that, in solution, they self-assembled into small aggregates, mainly dimers. Conversely, PINB isolated from hard varieties (PINB-D1b and PINB-D1d) are assembled into large aggregates while PINB-D1a formed small aggregates, mainly monomers. Mixed solutions of PINA and PINB formed heteromeric aggregates. The large PINB-D1b aggregates were retained even at a high (4:1) PINA/PINB weight ratio. Reversible dissociation of large aggregates into small aggregates suggested that weak interactions control the self-assembly of PINs. The aggregative properties of PINs have now to be taken into account when studying their interactions with other components to decipher the causal relationships between these proteins and grain hardness.     

Effects of sulphur,nitrogen, phosphorus,potassium, and water stress on dietary fibre fractions,starch, amino acids and on the biological value of potato protein

In pot experiments with greatly differing rates of N, P, K, and S, and 3 levels of water, dry matter (DM) yields of tubers varied from 28 to 454 g/pot. Especially P-, K- and S-deficiency reduced the starch content of boiled potatoes, from P from 74 to 59% in DM. S-deficiency increased soluble, insoluble and total digestible fibre (TDF) from about 9 to 12.4% TDF in DM of boiled potatoes. Lignin content of fresh potato DM was increased from 0.7 to 2.0 and from 0.8 to 3.7% by P- and K-deficiency. P-deficiency considerably increased arabinose, galactose, and uronic acid, and decreased glucose content. N-application and P-, K- and S-deficiency increased total- and NO₃-N concentrations which varied from 1.32 to 3.67% and from 17 to 400 ppm in DM. Water stress slightly decreased total-N content. Increasing N in DM, due to high N-rates or P- or K-deficiency, decreased concentrations in crude protein (CP) of all essential amino acids, whereas aspartic acid (asparagine) increased. S-deficiency caused particularly strong decreases in concentrations of essential amino acids from 1.28 to 0.49, 1.62 to 1.10, 5.24 to 3.68, and 5.59 to 2.57 g/16 g N of cystine, methionine, lysine and leucine, respectively. Glutamic acid (glutamine) content was increased from 15.7 to 27.6 g/16 g N by S-deficiency. Expressed as g amino acid/kg DM, all amino acid concentrations increased with increasing % N in DM. In N-balance trials with rats, increasing crude protein concentrations in DM of boiled potatoes increased the true digestibility (TD) of the protein from 72 to 90 but decreased the biological value (BV) from 89 to 65. S-deficiency caused a further reduction of the BV to 45. Excluding S-deficiency treatments, linear regression equations between CP concentrations and BV and TD gave correlation coefficients r of –0.94*** and 0.82***, respectively. There was close agreement between changes of BV and concentrations of first limiting amino acids (chemical score), with r=0.96***.     

基于主成分和聚类分析的冀花高油酸花生品种综合评价

利用3年表型和重测序数据分别对11个冀花高油酸花生品种进行主成分分析和聚类分析。结果发现,15个性状中脂肪含量变异系数最小为1.91%,除亚油酸外产量性状变异均大于品质变异系数,百果重与百仁重呈极显著正相关,油酸和亚油酸呈极显著负相关。主成分分析提取的前2个主成分累计贡献率达78.99%,利用表型性状对品种进行分类,结果与系谱关系部分一致。质控后获得320 000个分布均匀的高质量SNP位点,利用基因型数据将11个品种聚为4类,能够将同一组合衍生品种划分为同一类,结果与品种系谱关系一致。因此,利用基因型数据更能准确反映品种内在遗传基础,为种质资源的分类和利用提供参考。     

Effect of combined insecticide and fungicide treatments on newly sown swards of Italian and perennial ryegrass using two methods of sowing, two rates of seed and N fertilizer, with and without herbicide

The effects of six factors, each at two levels and in all combinations, on herbage yield and weed content of perennial ( Lolium perenne ) and Italian ( L. multiflorum ) ryegrass were assessed in four autumn sowings of field plots, in 3 years and at two sites. The factors were (i) perennial (PRG) or Italian (IRG), (ii) normal or low seed rate, (iii) drilling or broadcasting the seed, (iv) normal or low N fertilizer rate, (v) ryegrass fungicide seed treatment and post-emergence insecticide sprays (F + I) or untreated, and (vi) herbicide treatment or untreated. Overall, herbage yield at the first harvest was increased by F + I and IRG (all sowings), and the higher rates of seed (three sowings) and N (two sowings). Variable results were obtained for the other two factors. Increased yield was often associated with reduced weed content. Significant interactions between factors were obtained at two sowings; in particular, F + I increased yield of IRG by 12% and 22%, but had no effect on PRG. A second harvest, in the following spring, was taken for two sowings and there was no effect of F + I or the higher rates of seed and N. Thus, it is concluded that the desired aim when establishing grass swards of an adequate plant population without excessive competition from weeds appeared to be obtained even with plots receiving the least inputs.     

Variation of the amino acid scores and of the nitrogen-to-protein conversion factors in barley grain as a function of nitrogen content as compared with wheat and rye

Barley grains (9 samples from 7 cultivars) with nitrogen contents (N) ranging from 1.45 to 4.01% of dry matter were analysed for their amino acid (AA) composition with high accuracy from six different hydrolysates per sample. AA levels in grain increased as linear functions ofN with correlation coefficients close to unity. A comparison with literature data confirmed that the AA composition of any grain sample of normal barley can be predicted from itsN for all phenotypes and genotypes. AAs in grain protein changed as hyperbolic functions ofN which increased for Phe, Pro and Glx but more or less strongly decreased for the other AAs. By plotting AA scores againstN, barley proteins were shown to be always richer than wheat and rye in Val and Phe + Tyr; sometimes richer than both other species forN<2 (Lys); 2.2 (Leu and Ile); 3.4 (Thr); sometimes intermediate to wheat and rye above the latterN values. They were also intermediate in sulphur AAs forN<1.9 and drastically poorer forN>1.9. However, they were richer than both other species in Trp forN>1.6. The hyperbolic variations of non-protein nitrogen and nitrogen-to-protein conversion factors were determined as a function ofN and also compared with those of wheat and rye.     

The effects of intravenous administration of amino acids and glucose on the milk production of dairy cows consuming diets based on grass silage

Two experiments, using intravenous infusion of nutrients, were carried out with the aim of separating milk production responses due to the provision of amino acids as precursors of milk protein synthesis from those due to the provision of amino acids as glucose precursors. Diets were based on grass silage of restricted fermentation and barley‐based supplements because it has been suggested that these diets might provide insufficient glucose precursors to meet the needs of lactose synthesis. The silages used in the experiments were of similar lactic acid contents [62 and 63 g kg^–1 dry matter (DM)] but of different water‐soluble carbohydrate (WSC) contents (206 and 20 g kg^–1 DM in Experiments 1 and 2 respectively). In Experiment 1, four dairy cows were given the following treatments in a 4 × 4 Latin square arrangement with periods of 10 d: (1) basal diet (Basal), (2) Basal plus jugular infusion of 182 g d^–1 of amino acids simulating casein (TAA), (3) Basal plus 101 g d^–1 of essential amino acids (EAA), being the essential amino acid component of the TAA treatment and (4) Basal plus 101 g d^–1 of essential amino acids plus 50 g d^–1 of glucose (EAA + G), being the glucose equivalent of the non‐essential amino acid component of treatment TAA. All infusions increased (P < 0·05) the concentration of milk protein compared with Basal but only for TAA was the increase in the yield of milk protein statistically significant (P < 0·05), amounting to 68 g d^–1. Both TAA and EAA reduced (P < 0·05) the concentration of milk fat. There was no difference between EAA and EAA + G treatments. In Experiment 2, five dairy cows were given the following treatments in a 5 × 5 Latin square design with periods of 7 d: (1) basal diet (Basal), (2) Basal plus 182 g d^–1 of amino acids simulating casein (TAA), (3) Basal plus 182 g d^–1 of non‐essential amino acids as in casein (NEAA), (4) Basal plus 100 g d^–1 of glucose (G100) and (5) basal plus 230 g d^–1 of glucose (G230). G100 supplied the glucose equivalent of NEAA whereas G230 supplied the caloric equivalent of NEAA. Again, only for TAA was the increase in yield of milk protein statistically significant (P < 0·05), amounting to 83 g d^–1. Neither glucose treatment caused any statistically significant (P > 0·05) effect on the yield of milk protein nor the yield of milk lactose. It is concluded that, in both experiments, the primary nutritional limitation on milk protein output was the supply of amino acids as precursors of milk protein, there being no evidence to support a primary limitation due to glucose supply.     

Effect of a Bangladeshi home-cooking procedure on the amino acid content,trypsin inhibitor activity and in vitro digestibility of some legume seeds

Raw and cooked samples of cultivars ofLens esculenta (Lentils),Pisum sativum (peas),Phaseolus vulgaris (beans),Phaseolus aureus (navy beans)Cicer arietnum (gram), andLathyrus sativus (dhal) as well as precooked commercial products were analysed for amino acids, trypsin inhibitor activity and in vitro protein digestibility. Of the fifteen samples used in the study one lentil sample, one pea sample, two gram samples and one sample of khesari dhal were from Bangladesh, one gram sample was from Sri Lanka. The other samples were obtained either in shops in Norway or from an industrial firm. The latter were also obtained precooked and dried. The two samples obtained in shops were used with hull and dehulled.Neither cooking by a Bangladeshi household procedure nor industrial precooking and drying had any effect on the amino acid contents of the samples.Cooking and precooking reduced the trypsin inhibitor activity of the raw samples more when the original activity was high then when it was low. The inhibitor activity was similar between samples after cooking.Cooking and precooking and drying increased the in vitro protein digestibility in all samples except in the lentils in which the digestibility was reduced.In the raw samples protein digestibility was negatively correlated with the trypsin inhibitor activity.     

Effects of the amino acid analog, 5-methyltryptophan on protoplast survival,plating efficiency and free tryptophan levels in tubers of regenerated potato plants

In an attempt to improve nutritional qualities of the potato by exploiting variation associated with protoplast regeneration, Russet Burbank leaf protoplasts were cultured in cell layer (CL) medium containing the amino acid analog, 5-methyltryptophan (5-MT) at concentrations from 0 to 286 μM. At three day intervals, numbers of viable cells and dividing colonies were recorded to determine effects of 5-MT concentration on cell viability during the 14 day incubation period. Repeated count data were used in a computer program to construct survival profiles. Decline in cell populations was generally slight during the first 5 days in culture. Between day 5 and 11, survival rate dropped dramatically, averaging 10–12% per day regardless of concentration. As surviving cells began to divide, a leveling trend in the curves was noted between days 11 and 14. Reduced plating efficiency was only associated with the 103 and 286 μM treatments. No plants were regenerated from colonies exposed to 5-MT concentrations in CL greater than 34.4 μM nor were differences in free tryptophan found between tubers of protoclones and Russet Burbank.