Significance of the amino acid pool in nitrogen metabolism of <i>Penicillium griseofulvum</i>

Bent, KJ

doi:10.1042/bj0920280

Cited by 14 publications

(2 citation statements)

References 11 publications

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“…Some key metabolic differences in amino acids no doubt occur (e.g. the occurrence of alanine dehydrogenases in insects and bacteria but not mammals, and lysine metabolism in fungi), but nitrogen isotope studies on amino acids from diverse species including bacteria, fungi, fish and birds echo the patterns seen in the larger mammalian literature using labelled 15 N compounds (Bent 1964 ; Richter and Gruhn 1977 ; Gruhn 1987 ; Macko et al 1987 ; Chalot et al 1995 ; Iwata and Deguchi 1995 ; Rodicio et al 2003 ). Thus, although there are metabolic variations across heterotrophs, the evidence suggests that the mechanism outlined here for the patterning in ‘trophic’ and ‘source’ amino acids is probably pertinent across most organisms.…”

Section: Heterotrophic Nitrogen Metabolismmentioning

confidence: 99%

‘Trophic’ and ‘source’ amino acids in trophic estimation: a likely metabolic explanation

2017

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Amino acid nitrogen isotopic analysis is a relatively new method for estimating trophic position. It uses the isotopic difference between an individual’s ‘trophic’ and ‘source’ amino acids to determine its trophic position. So far, there is no accepted explanation for the mechanism by which the isotopic signals in ‘trophic’ and ‘source’ amino acids arise. Yet without a metabolic understanding, the utility of nitrogen isotopic analyses as a method for probing trophic relations, at either bulk tissue or amino acid level, is limited. I draw on isotopic tracer studies of protein metabolism, together with a consideration of amino acid metabolic pathways, to suggest that the ‘trophic’/‘source’ groupings have a fundamental metabolic origin, to do with the cycling of amino-nitrogen between amino acids. ‘Trophic’ amino acids are those whose amino-nitrogens are interchangeable, part of a metabolic amino-nitrogen pool, and ‘source’ amino acids are those whose amino-nitrogens are not interchangeable with the metabolic pool. Nitrogen isotopic values of ‘trophic’ amino acids will reflect an averaged isotopic signal of all such dietary amino acids, offset by the integrated effect of isotopic fractionation from nitrogen cycling, and modulated by metabolic and physiological effects. Isotopic values of ‘source’ amino acids will be more closely linked to those of equivalent dietary amino acids, but also modulated by metabolism and physiology. The complexity of nitrogen cycling suggests that a single identifiable value for ‘trophic discrimination factors’ is unlikely to exist. Greater consideration of physiology and metabolism should help in better understanding observed patterns in nitrogen isotopic values.

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Section: Heterotrophic Nitrogen Metabolismmentioning

confidence: 99%

‘Trophic’ and ‘source’ amino acids in trophic estimation: a likely metabolic explanation

2017

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“…This suggests that only mycelium formed in the presence of excess tryptophan is conditioned, at a later stage of development, to a high level of alkaloid synthesis. Although the effect might be attributed to a difference in nutrient uptake between older hyphae and growing tips, studies with other fungi (5,6,36,37) have indicated little distinction between different parts of the mycelium in assimilation and metabolism of amino acids. Tryptophan appears to be taken up readily by growing or resting mycelium of Claviceps strain HLX 123.…”

Section: Discussionmentioning

confidence: 94%

Effect of tryptophan on alkaloid biosynthesis in cultures of a Claviceps species

Lc¹

1970

Can. J. Microbiol.

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VINING, L. C. 1970. Effect of tryptophan on alkaloid biosynthesis in cultures of a Claviceps species.Can. J. Microbial. 16: 473480. Addition of tryptophan to cultures of Claviceps strain HLX 123 caused a large increase in alkaloid production. For maximum effect a supplement of at least 250 mg/l was required within 1 day after inoculation. When ~-tryptophan-B-l4C was used the labeled amino acid accumulated in the mycelium until alkaloid synthesis began, near the end of the growth phase. Intracellular tryptophan was then rapidly incorporated into alkaloids which were excreted into the culture fluid. L-Tryptophan-e-14C added to cultures during the period of rapid alkaloid synthesis was efficiently incorporated into alkaloids, but caused only a small increase in yield. The results suggest that tryptophan stimulates alkaloid production mainly through an increase in activity of the alkaloid-synthesizing enzyme system. The role of tryptophan in the regulatory process is discussed.

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Uptake of ¹⁴C‐glucose by Botryodiplodia theobromae Pat and changes in its carbohydrate content during growth

Olofinboba

1973

J of Basic Microbiology

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There is a rapid uptake of 14C-glucose and unlabelled glucose during the period of pigmentation of the mycelium of Botryodiplodia theobromae PAT. Incorporation of 14C-glucose into structural components of the mycelium started within 24 hours of incubation and progressively increased until the 14th day of growth.The mycelium contains glucose, isomaltose, and sucrose. There is a decrease in these carbohydrates during autolysis. Autolysis in B. theobromae occurs in an acid medium of p H 5.2.The growth of Botryodiplodia theobromae PAT, the causal organism of diseases of many economic tropical crops (ALASOADURA 1970) in culture can be divided into two distinct phases : Hyaline mycelium is produced during the first 3 -4 days of growth and this phase is followed by rapid pi gmentationof most of the mycelium. Microscopic examination of the mycelium during pigmentation shows a mixture of hyaline, thin hyphae, and pigmented stout hyphae. Observation of cross-section of wood of Antiaris africana stained blue by the fungus also reveals the two types of hyphae, with the food-storing parenchyma cells predominantly infected by the hyaline hyphae. OLOFINBOBA and LAWTON (1968) showed that the parenchyma cells of the wood of A . africana contain various carbohydrates which are rapidly utilized by the fungus. They suggested that the hyaline hyphae are nutritional in function. It was, however, not clear if rate of carbohydrate utilization was influenced by the pigmentation of some of the hyphae.Few reports (LAHOZ 1966) have appeared in recent years on the chemistry of autolysis of certain filamentous fungi. Most of the investigation was on the behaviour of nitrogenous materials present in the mycelium and the culture medium of such fungi (BENT 1964, BENT and MORTON 1964). LAHOZ et al. (1966) made the initial attempt to study the changes in carbohydrates during autolysis in Aspergillus flavus. Not so much has been reported about the changes in carbohydrates during growth and autolytic phases of fungi development.The present study is to investigate the influence of pigmentation on the utilization of glucose by B. theobromae. It is also designed to study the qualitative and quantitative changes in the carbohydrates of the mycelium of B. theobromae during growth and autolytic phases. Material and methodsUptake of 1%-glucose: The isolate used in this study was from blue-stained xylem of Antiaris africana. The culture medium consisted of the following composition (g/l distilled water): &(NO,), 0.5, KNO, 0.125, MgSO, x 7 H,O 0.125, KH,PO, 0.125. 5 ml of the 34*

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Significance of the amino acid pool in nitrogen metabolism of Penicillium griseofulvum

Cited by 14 publications

References 11 publications

‘Trophic’ and ‘source’ amino acids in trophic estimation: a likely metabolic explanation

‘Trophic’ and ‘source’ amino acids in trophic estimation: a likely metabolic explanation

Effect of tryptophan on alkaloid biosynthesis in cultures of a Claviceps species

Uptake of ¹⁴C‐glucose by Botryodiplodia theobromae Pat and changes in its carbohydrate content during growth

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Significance of the amino acid pool in nitrogen metabolism of Penicillium griseofulvum

Cited by 14 publications

References 11 publications

‘Trophic’ and ‘source’ amino acids in trophic estimation: a likely metabolic explanation

‘Trophic’ and ‘source’ amino acids in trophic estimation: a likely metabolic explanation

Effect of tryptophan on alkaloid biosynthesis in cultures of a Claviceps species

Uptake of 14C‐glucose by Botryodiplodia theobromae Pat and changes in its carbohydrate content during growth

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Uptake of ¹⁴C‐glucose by Botryodiplodia theobromae Pat and changes in its carbohydrate content during growth