Low AA Research Articles

Embryogenic Competence of Immature Wheat Embryos: Genotype, Donor Plant Environment, and Endogenous Hormone Levels

The genotype and the environment in which donor plants grow influence embryogenic competence of immature wheat (Tritium Estevan L.) embryos and levels of endogenous hormones in kernels. We studied relationships between embryonic competence and hormone levels in kernels and Calli of PC YT 10 (highly competent) and Yaqui 50 (nearly incompetent) wheat grown at 15 and 25°C. Endogenous levels of abscissa acid (ABA), in dole‐3‐acetic acid (AA), and stockings were determined for kernels at 0, 4, 8, and 12 d past an thesis (DOPA). Immature embryos were cultured at 12 DOPA and hormone content of Calli was determined at 7, 14, 21, and 28 d past culture initiation (DP|). Somatic embryos were counted at 28 DIP. Embryonic competence was associated with low AA and ABA levels in kernels from 0 to 12 DOPA, high seating to AA ratios in kernels at 4 DOPA, and high stoking to auxin ratios in Calli. Incompetence in Yaqui 50 may be due to low stoking to auxin ratios in kernels at 4 DOPA and sharp increases in kernel AA and/or ABA levels prior to embryo excision (12 DOPA). Low temperatures during donor plant growth delayed the rise in AA and ABA in Yaqui 50 kernels and significantly increased the embryogenic response from both Yaqui 50 and PCYT 10 embryos. It may be possible to increase competence of nearly nonembryogenic wheat lines by growing donor plants in cool conditions, which appear to delay the accumulation of IAA and ABA in kernels.

Vitamin C in premature and full-term human neonates.

Plasma concentrations of vitamin C (ascorbic acid, AA) are known to be higher in full-term human neonates than their mothers. Immaturity of placental AA transport could result in low plasma AA concentrations in pre-term infants. We found that plasma AA concentrations in umbilical cord blood of 25 full-term neonates (38-42 weeks gestation) and 33 pre-term neonates (24-36 weeks gestation) were always significantly higher than in the corresponding maternal blood (P < 0.0001). However, plasma AA levels were significantly higher in pre-term than in full-term infants (146 ± 93 vs 102 ± 27 μM, respectively; P = 0.03). Furthermore, a rapid and sharp decrease in plasma AA concentrations from 229 ± 166 μM to 45 ± 18 μM (P < 0.0001) over the first 3 days of life was observed in eight very low birth weight infants (460-1090 g, 24-28 weeks gestation). These findings raise important questions about the in utero functions of AA in the developing fetus and the adequacy of postnatal vitamin C supplementation of the premature infant.

Amino acid supplementation to growing and finishing steers (1996)

One hundred British and British cross steers, averaging 631 lb ( initial wt) were used in a growing and finishing study to evaluate the effects of unprotected amino acid supplementation on cattle performance and carcass characteristics. All diets contained 1% of a nonprotein nitrogen source, and treatments were: no additional supplemental protein (UREA), 2) supplemental protein from soybean meal (SBM), 3) 13 grams/day of an amino acid supplement (Low AA), and 4) 26 grams/day of an amino acid supplement (High AA). The Low AA treatment supplied 2 grams methionine, 8 grams lysine, 2 grams threonine, and 1 gram tryptophan per day, whereas the High AA treatment provided twice those amounts. The grower diet was based on whole-plant sorghum silage, and the finishing diet was based on rolled corn and corn silage. During the growing period, gains were higher (P<.05) for SBM-supplemented steers than for UREA steers and intermediate for amino acid-supplemented steers. Intakes were higher for steers supplemented with Low AA than for those supplemented with UREA or High AA. Few significant differences among treatments were observed in cattle performance during the finishing period. Hot carcass weights, dressing percentage, KPH fat, and yield grade were unaffected by amino acid supplementation. In this study, supplementing growing and finishing cattle with unprotected amino acids did not significantly improve steer performance or carcass characteristics, suggesting either that these amino acids were not limiting in these steers or that not enough of these supplemented amino acids escaped ruminal degradation to affect steers' performance.

The infrared and Raman spectra, conformations and ab initio calculations of 4-azidobut-1-yne

The IR spectra of 4-azidobut-1-yne were recorded in the vapour and liquid stated and as amorphous and crystalline solids at liquid nitrogen temperature. The Raman spectra of the liquid in the temperature range 232–295 K and as a crystal at 148 K were obtained. Additionally, IR spectra in argon and nitrogen matrices were recorded, applying the hot nozzle technique.The compound can exist in five conformers labelled GG, GG′, GA, AG and AA, referring to the confromations around the C-C and the C-N bonds, respectively. Fully optimized ab initio geometries for all five conformers have been calculated at the SCF level. The conformers can be divided into the low energy conformers GG, AA and AG (0, 0.1, 0.3 kJ mol1−) and the high energy conformers GA and GG′ (both 2.4 kJ mol1−).Some of the strongest bands missing in the crystal increased their intensities in the matrix spectra upon annealing, suggesting that the most stable conformer present in the crystal. The scaled abinitio frequencies indicated that the conformer present in the crystal phase is AG. In the liquid and matrices the most stable conformer is GG followed by AG and AA. All the five conformers were observerd in the liquid at room temperature and trapped in the argon matrix.

Relationship of Surrender and Narcissism to Involvement in Alcohol Recovery

Subjects were participants in two self-help groups, Alcoholics Anonymous (AA; n = 45) and Rational Recovery (RR; n = 10). Two groups of AA participants were distinguished based on degree of AA involvement. RR participants constituted the third group. As predicted, the Surrender Instrument was able to discriminate between the High AA, Low AA, and RR groups, with the High AA group scoring above the other groups on surrender. Results suggest there is more to the act of surrender than level of involvement, length of sobriety, or degree of dependence on alcohol. Some support is provided for AA's philosophy that surrendering to a Higher Power occurs during the course of alcohol recovery. Results suggested there is a negative correlation between pathological narcissism and surrender. Unfortunately, firm conclusions could not be drawn from this study regarding narcissism.

Recognition of triiodothyronine-containing epitopes in canine thyreoglobulin by circulating thyroglobulin autoantibodies

SUMMARY Serum triiodothyronine autoantibody (T3 AA), triiodothyronine (T3), and thyroxine (T4) concentrations were determined in 45 canine sera containing substantial amounts of thyroglobulin autoantibodies (Tg AA); sera also were assayed to investigate the ability of free T3 to inhibit Tg AA binding to canine Tg, Serum T3 AA concentrations defined 2 groups of sera; 28 sera had low T3 AA concentration (≤ 20 ng/ ml) and 17 sera had high T3 aa concentration (≥ 250 ng/ml). Direct linear correlation between T3 AA concentration and apparent serum T3 concentration was observed (r = 0.75). Serum with low T3 AA concentration had apparent T3 concentration that was significantly (P &lt; 0.01) lower than that in serum with high T3 AA concentration. Mean serum T4 concentration was not significantly different between serum with low or high T3 AA concentration. Mean Tg AA activity was significantly (P &lt; 0.05) lower in serum with low T3 AA concentration than in serum with high T3 AA concentration. Addition of free T3 to serum significantly (P &lt; 0.05) decreased detectable activity of Tg AA in both groups of sera. However, significant difference in magnitude of the reduction was not observed between sera with low or high T3 AA concentration. Results indicate that a fraction of Tg AA recognizes T3-containing epitopes in Tg. Increased prevalence of T3 AA for serum with high Tg AA activity indicates that T3 AA may be another valid indicator of lymphocytic thyroiditis. These antibodies may be generated against the hormonogenic epitopes of Tg.

Quantitative association between altered plasma esterified omega-6 fatty acid proportions and psychological stress

Medical students (MS) tested during the first year of medical school showed both greater stress on the Brief Symptom Inventory and lower plasma proportions of total esterified arachidonic acid (AA, C20:4n-6), and its omega-6 fatty acid (FA) precursor, linoleic acid (C18:2n-6) than control laboratory workers. This association suggests that omega-6 FA metabolism may be affected during stress. Low AA values might result from depletion of plasma stores for immunoregulatory prostenoids formation or from modification of metabolic pathways by cortisol or other cytokine compounds implicated in stress. Values for other major FA and the omega-3 neuronal metabolic substrate, docosahexaenoic acid (DHA, C22:6n-3) were similar between students and controls. The clear preservation of the omega-3 FA pathway suggests their programmed availability for neuronal function during stress. Since plasma FA proportions may affect immune cell membrane function(s), we suggest that altered values of plasma FAs may be an important component of the physiological effects of psychological stress.

Free amino acid levels in muscle and liver of a patient with glucagonoma syndrome

This study set out to measure the amino acid concentrations in the femoral artery, femoral vein, hepatic vein, muscular and hepatic tissue, and urine of a patient with the glucagonoma syndrome. The total plasma amino acid concentration was severely reduced on admission (737 μmol/L, 26% of normal), with only a slight increase during intravenous administration of 200 g of amino acids per day. The total intracellular amino acid levels in the muscle were 86%, and those of the liver were 47% of the normal range. Only 0.62% of the amino acids administered were found in the urine. Arteriovenous amino acid concentration differences across the muscle and splanchnic tissue indicated the release of amino acids (mainly glutamine, glycine, and alanine) from the muscle and the absorption of amino acids by the splanchnic bed. This study shows that the infusion of a high amount of amino acids cannot increase the subnormal plasma AA levels of patients with the glucagonoma syndrome. the low total plasma AA levels are paralleled by decreased intracellular free amino acid levels in the muscle and liver.

Degradation of amyloid proteins with protease I from Aspergillus oryzae. In vivo increase in SAA clearance rate after enzyme infusion.

The effect of the thrombolytic enzyme protease I from Aspergillus oryzae (brinase) on the amyloid protein AA was investigated. The effect of the enzyme on purified, low molecular weight protein AA was very high. Protein AA in intact amyloid fibrils suspended in neutral buffer was also degraded by the enzyme, although at a much lower rate. Amyloid fibrils in tissue sections could also be attacked and removed, leaving the tissue structure fairly intact. The in vivo effect of brinase on protein SAA was demonstrated in rabbits by an increase in the clearance rate of SAA after enzyme infusion.

The influence of sex and age on the deposition of L-xyloascorbic acid in tissues of guinea-pigs.

1. Young male and female guinea-pigs of similar age and male guinea-pigs of various ages were given daily oral supplements of vitamin C (L-xyloascorbic acid) (AA) on a body-weight basis for periods of 10–15 d and the resulting concentration of AA in several organs was determined.2. There was no difference between the sexes in the concentrations of AA in the adrenal glands and spleen. The concentration of AA in the spleen, adrenal glands and eye lens was significantly lower in older animals, and in brain it was significantly higher than the corresponding values for the young guinea-pigs.3. The tissue deposition after oral administration of AA for 10 d was compared with that resulting from intramuscular injection of the same quantity of AA over 10 d in males aged 60 d, males aged 500 d and females aged 500 d. In the 60-d-old guinea-pigs intramuscular injection raised the concentration of AA in the spleen and adrenal glands 35% and 50% respectively above that resulting from oral dosing. In the older guinea-pigs (500 d) the corresponding values were 108% and 127% respectively. It is concluded that reduced gastrointestinal absorption is, at least in part, responsible for the low AA concentrations in certain organs from older guinea-pigs. In the 500-d-old guinea-pigs there was no significant difference between the AA levels in the spleen, adrenals and brain of the two sexes, but AA level in the lens of females was significantly lower than that in males, irrespective of the mode of administration of the AA.

Vitamin C activity of D-isoascorbic acid for the guinea pig

Guinea pigs fed with a synthetic diet or a rabbit ration were depleted of vitamin C for 17 days. The scorbutic animals were treated daily during 2 months with 40 mg D-isoascorbic acid (IAA) or 2 mg L-ascorbic acid (AA). Both isomers restored the growth of the animals and caused the disappearance of scorbutic symptoms. For 3 weeks, the two diets gave similar response, after which the animals fed with the rabbit ration grew much less. Animals given IAA ate less and had smaller weight gains than those given AA; this effect was overcome by pair-feeding. Only a small proportion of administered IAA was recovered in the organs and in the urine. The total ascorbic acid content (AA and IAA) of the IAA-treated animals was less than that of the AA-treated animals. The low AA content of the organs of the IAA-treated animals indicated that IAA had no significant sparing action on AA.