NUTRITIONAL REQUIREMENTS OF ARTHROBACTER TERREGENS

1953 ◽  
Vol 31 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Margaret O. Burton ◽  
A. G. Lochhead

Vitamin and amino acid requirements have been established for Arthrobacter terregens n. sp., an organism found to require an unknown growth factor present in soil extract, liver extract, and culture filtrates of Arthobacter pascens n. sp. Apart from this unknown factor, concentrates of which promote growth at less than 0.1 μgm. per ml., biotin, thiamine, and pantothenic acid were found to be essential. With adequate mineral supplement the nitrogen requirements could be fulfilled by l-glutamic acid, though the latter could be replaced by combinations of other amino acids.

2002 ◽  
Vol 76 (16) ◽  
pp. 7976-7986 ◽  
Author(s):  
Valerie M. Nappi ◽  
Lisa M. Petti

ABSTRACT The bovine papillomavirus E5 protein activates the cellular platelet-derived growth factor β receptor (PDGFβR) tyrosine kinase in a ligand-independent manner. Evidence suggests that the small transmembrane E5 protein homodimerizes and physically interacts with the transmembrane domain of the PDGFβR, thereby inducing constitutive dimerization and activation of this receptor. Amino acids in the receptor previously found to be required for the PDGFβR-E5 interaction are a transmembrane Thr513 and a juxtamembrane Lys499. Here, we sought to determine if these are the only two receptor amino acids required for an interaction with the E5 protein. Substitution of large portions of the PDGFβR transmembrane domain indicated that additional amino acids in both the amino and carboxyl halves of the receptor transmembrane domain are required for a productive interaction with the E5 protein. Indeed, individual amino acid substitutions in the receptor transmembrane domain identified roles for the extracellular proximal transmembrane residues in the interaction. These data suggest that multiple amino acids within the transmembrane domain of the PDGFβR are required for a stable interaction with the E5 protein. These may be involved in direct protein-protein contacts or may support the proper transmembrane alpha-helical conformation for optimal positioning of the primary amino acid requirements.


Author(s):  
C.J. Seal ◽  
D.S. Parker ◽  
J.C. MacRae ◽  
G.E. Lobley

Amino acid requirements for energy metabolism and protein turnover within the gastrointestinal tract are substantial and may be met from luminal and arterial pools of amino acids. Several studies have demonstrated that the quantity of amino acids appearing in the portal blood does not balance apparent disappearance from the intestinal lumen and that changing diet or the availability of energy-yielding substrates to the gut tissues may influence the uptake of amino acids into the portal blood (Seal & Reynolds, 1993). For example, increased net absorption of amino acids was observed in animals receiving exogenous intraruminal propionate (Seal & Parker, 1991) and this was accompanied by changes in glucose utilisation by the gut tissues. In contrast, there was no apparent change in net uptake of [l-13C]-leucine into the portal vein of sheep receiving short term intraduodenal infusions of glucose (Piccioli Cappelli et al, 1993). This experiment was designed to further investigate the effects on amino acid absorption of changing glucose availability to the gut with short term (seven hours) or prolonged (three days) exposure to starch infused directly into the duodenum.


1988 ◽  
Vol 8 (3) ◽  
pp. 1247-1252 ◽  
Author(s):  
E Lazar ◽  
S Watanabe ◽  
S Dalton ◽  
M B Sporn

To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the sequence for the fully processed, 50-amino-acid human TGF-alpha. The wild-type and mutant proteins were expressed in a vector by using a yeast alpha mating pheromone promoter. Mutations of two amino acids that are conserved in the family of the EGF-like peptides and are located in the carboxy-terminal part of TGF-alpha resulted in different biological effects. When aspartic acid 47 was mutated to alanine or asparagine, biological activity was retained; in contrast, substitutions of this residue with serine or glutamic acid generated mutants with reduced binding and colony-forming capacities. When leucine 48 was mutated to alanine, a complete loss of binding and colony-forming abilities resulted; mutation of leucine 48 to isoleucine or methionine resulted in very low activities. Our data suggest that these two adjacent conserved amino acids in positions 47 and 48 play different roles in defining the structure and/or biological activity of TGF-alpha and that the carboxy terminus of TGF-alpha is involved in interactions with cellular TGF-alpha receptors. The side chain of leucine 48 appears to be crucial either indirectly in determining the biologically active conformation of TGF-alpha or directly in the molecular recognition of TGF-alpha by its receptor.


1980 ◽  
Vol 239 (6) ◽  
pp. G493-G496 ◽  
Author(s):  
E. J. Feldman ◽  
M. I. Grossman

Using intragastric titration in dogs with gastric fistulas, dose-response studies were carried out with liver extract and with a mixture of amino acids that matched the free amino acids found in liver extract. All solutions were adjusted to pH 7.0 and osmolality to 290 mosmol x kg-1. Doses are expressed as the sum of the concentrations of all free amino acids. At each dose studied (free amino acid concentration: 2.8, 5.6, 11, 23, and 45 mM), acid secretion in response to the free amino acid mixture was not significantly different from that of liver extract. The peak response to both liver extract and the free amino acid mixture occurred with the 23-mM dose and represented about 60% of the maximal response to histamine. The serum concentrations of gastrin after liver extract and the amino acid mixture were not significantly different. It is concluded that in dogs with gastric fistula, gastric acid secretion and release of gastrin were not significantly different in response to liver extract and to a mixture of amino acids that simulated the free amino acid content of liver extract.


1969 ◽  
Vol 47 (3) ◽  
pp. 323-327 ◽  
Author(s):  
J. E. Knipfel ◽  
H. G. Botting ◽  
F. J. Noel ◽  
J. M. McLaughlan

Changes in plasma amino acid (PAA) concentrations effected by force-feeding glucose to rats were studied in two experiments. Attempts were made to relate PAA concentration changes to amino acid requirements, previous diet, time after feeding glucose, and composition of several body proteins. Distribution of 14C-lysine between blood and tissues was examined in an additional rat experiment. Previous diet did not affect the relative quantities of amino acids removed from plasma (PAA removal pattern) after glucose force-feeding. Minimal PAA concentrations occurred by 40 min after glucose administration. The PAA removal pattern was not distinctly related to either amino acid requirements or to any particular body protein composition. Results of administering 14C-lysine simultaneously with glucose indicated that decreased plasma 14C-lysine levels were caused by increased tissue uptake of 14C, likely mediated by insulin. Muscle acted as the major recipient of 14C from plasma, with liver a lesser and more dynamic reservoir of 14C accumulation. Work is continuing to further clarify the significance of the PAA removal pattern, caused by the force-feeding of glucose.


2021 ◽  
pp. 1-8
Author(s):  
Adeyeye EI ◽  
◽  
Idowu OT ◽  

This article reports the amino acid composition of the Nigerian local cheese called ‘wara’. ‘Wara’ is made by boiling cow milk with some added coagulant to cuddle the milk protein resulting in coagulated milk protein and whey. ‘Wara’ used to be an excellent source of nutrients such as proteins, fats, minerals and vitamins. Samples were purchased in Ado-Ekiti, Nigeria. Amino acid values were high (g/100g crude protein) in Leu, Asp, Glu, Pro, Phe, Arg with total value of 97.7. The quality parameters of the amino acids were: TEAA (42.6g/100g and 43.6%) whereas TNEAA (55.1g/100g and 56.4%); TArAA (12.8g/100g and 13.1%); TBAA (14.2g/100g and 14.5%); TSAA (3.10g/100g and 3.17%); %Cys in TSAA (51.4); Leu/Ile ratio (1.74); P-PER1 (2.65); P-PER2 (2.48); P-PER3 (2.41); EAAI1 (soybean standard) (1.29) and EAAI2 (egg standard) (99.9); BV (97.2) and Lys/Trp ratio (3.62). The statistical analysis of TEAA/TNEAA at r=0.01 was not significantly different. On the amino acid scores, Met was limiting (0.459) at egg comparison, Lys was limiting at both FAO/WHO [24] and preschool EAA requirements with respective values of 0.966 and 0.97. Estimates of essential amino acid requirements at ages 10-12 years (mg/kg/day) showed the ‘wara’ sample to be better than the standard by 3.72-330% with Lys (3.72%) being least better and Trp (330%) being most. The results showed that ‘wara’ is protein-condensed which can be eaten as raw cheese, flavoured snack, sandwich filling or fried cake.


2007 ◽  
Vol 2007 ◽  
pp. 182-182
Author(s):  
Forouzan Tabatabaie ◽  
Hassan Fathi ◽  
Mohsen Danesh

Whole soybean has 40-42 percent CP and used as high energy-protein supplement for early lactation dairy cows. However, the protein is highly degradable, so small amounts of amino acids can be reached to small intestine to meet high amino acid requirements of early lactating cows. Therefore, various chemical and physical treatments have been suggested to decrease ruminal protein degradability of soybeans. The practical use and application of any one method to lower ruminal feed degradability is dependent not only on its efficacy but also on its cost effectiveness, safety and ease of application. For these reasons, heat treatment is the most commonly used physical method (Plegge et al., 1985). The purpose of this study was to determine how roasting of soybeans affect plasma essential amino acid concentrations in early lactation cows.


Author(s):  
M.F. Fuller ◽  
R. McWilliam ◽  
T.C. Wang

The optimal balance of amino acids in the diet of the growing pig was estimated by ARC (1981) on the basis of a number of disparate studies augmented by data on the amino acid composition of the whole body on the premise that the amino acids incorporated into accreted body proteins are the major determinant of requirements and that this pattern is not distorted by inequalities in the utilisation of individual amino acids. In an accompanying paper (Wang & Fuller, paper no. 91) an optimal pattern was derived by direct experiment which was shown to be utilised better than that described by ARC (1981). That pattern, however, which related to one particular rate of nitrogen input and the particular rate of protein accretion which that input supported, includes two components, a requirement for maintenance and a requirement for protein accretion. There is clear evidence from studies with rats and chicks that the optimal pattern of amino acids for maintenance and growth are quite different and so the optimal pattern for any particular rate of growth will depend on the relative contributions of the two components. The purpose of this experiment was to estimate both.


1950 ◽  
Vol 28c (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. H. Wallace ◽  
A. G. Lochhead

A study was made of the more specific amino acid requirements of bacteria from the rhizospheres of clover, flax, and wheat plants for which a chemically defined medium containing 23 amino acids provided essentials for maximum growth. Of seven groups of amino acids, the sulphur-containing group (cysteine, methionine, and taurine) was found to be of special significance, the omission of this group resulting in a pronounced decrease in the percentage of organisms able to develop. Further study of organisms dependent upon this group of amino acids for growth showed methionine to be by far the most essential compound. While evident for bacteria from the rhizosphere of all three crops, the effect was more pronounced in the case of clover than with flax or wheat.


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