Determination of the D and L isomers of some protein amino acids present in soils

Pollock, Glenn E.; Cheng, Chunyang; Cronin, Sonja E.

doi:10.1021/ac50009a008

Cited by 57 publications

(14 citation statements)

References 19 publications

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“…It can be seen that peaks corresponding in retention time to each of the seven possible six-carbon chain isomers and to norvaline are present. This may be due in part to coincidence in retention time with an unknown component(s) (note the asymmetry of the leading edge of peak 13), although epimerization of L-isoleucine during the hydrolysis step would contribute to the D-aUoisoleucine content of the sample (Pollock et al 1977). Well resolved paired peaks of about equal size are seen corresponding to the enantiomorphs of pleu (6,7) and 2-a-2,3-dmba (10,11).…”

Section: Resultsmentioning

confidence: 99%

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Amino acids of the murchison meteorite:

1981

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Six of the seven chain isomers of six-carbon acyclic primary alpha-amino alkanoic acids (leucine isomers) have been either identified or confirmed in hot-water extracts of the Murchison meteorite using combined gas chromatography-mass spectrometry (GC-MS) and ion exchange chromatography. 2-Amino-2-ethylbutyric acid, 2-amino-2,3-dimethylbutyric acid, pseudoleucine, and 2-methylnorvaline were positively identified by GC-MS. These amino acids have not been previously reported to occur in natural materials and may be uniquely meteoritic in origin. The presence of leucine and isoleucine (including the diastereoisomer, alloisoleucine) was confirmed. Peaks corresponding to norleucine were seen by ion-exchange and gas chromatography but characteristic mass spectra were not obtained. The alpha-branched chain isomers in this series are quantitatively the most significant. These results are compared with literature data on amino acid synthesis by electrical discharge and Fischer-Tropsch-type catalysis. Neither model system produces an amino acids suite that is completely comparable to that found in the Murchison meteorite.

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Section: Resultsmentioning

confidence: 99%

“…The dry extract used for GC-MS analysis was dissolved in a small volume of 0.01N HC1 for desalting (Pollock et al 1977). Fragments weighing 15.5g were used for the GC-MS analysis and interior fragments weighing 0.22g were used for quantitative analysis by ion exchange chromatography.…”

Section: Methodsmentioning

confidence: 99%

Amino acids of the murchison meteorite:

1981

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“…Gyttja can absorb contaminants such as bacteria, fungi, and molds or loose material through leaching. In addition, D-aspartic acid is commonly produced by bacteria (Pollack et al 1977).…”

Section: Discussionmentioning

confidence: 99%

Late Quaternary history of the Lake O'Hara region, British Columbia – an evaluation of sedimentation rates and bulk amino acid ratios in lacustrine records

Reasoner¹,

Rutter²

1988

Can. J. Earth Sci.

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Lake O'Hara (subalpine) and Opabin Lake (alpine) are situated directly adjacent to a high section of the Continental Divide in the central Canadian Rocky Mountains. Core samples recovered from the lakes show a consistent stratigraphy comprising gyttja and underlying inorganic clastic sediments. The gyttja contains Bridge River (2350 years BP) and Mazama (6800 years BP) tephras and is separated from the lower clastic sediments by a sharp, conformable contact. Radiocarbon dates obtained from conifer needles, extracted from directly above the contact, indicate that deglaciation had proceeded upvalley from the O'Hara basin prior to ca. 10 100 years BP. Preliminary palaeobotanical and macrofossil data suggest that a Pinus-Abies forest with lesser Picea was established in the vicinity of Lake O'Hara by this time. Consequently, the minimum age of moraine systems situated downvalley from Lake O'Hara is Late Wisconsinan.Mean annual sedimentation rates were derived from sediment thickness data from 14 Lake O'Hara and 2 Opabin Lake cores. Averaged total sedimentation rate values from the Lake O'Hara cores are 0.13 mmlyear (post-Bridge River), 0.13 mmlyear (Mazama -Bridge River) and 0.05 mmlyear (1 1 000 years BP -Mazama). Averaged total sedimentation rate values from the Opabin Lake cores are 0.19 mmlyear (post-Bridge River), 0.07 mmlyear (Mazama -Bridge River), and 0.06 mmlyear (8530 years BP -Mazama). Higher total sedimentation rates in post-Bridge River sediments of Opabin Lake are presumably related to climatic conditions associated with more extensive upvalley ice during the last ca. 2300 years. Highly variable sedimentation rate data obtained from the Lake O'Hara cores suggest that the use of sedimentation rate data as a proxy record of upvalley glacial activity is inappropriate in the Lake O'Hara setting where inflowing glacial stream systems are intermpted by upvalley lake basins.Aspartic acid D/L ratios were derived from bulk gyttja samples of known age from seven Lake O'Hara and one Opabin Lake core. In all but two cases, aspartic acid DIL ratios increase consistently with respect to sediment age. The increasing downcore trends in the aspartic acid D/L ratios suggest the possibility of using amino acid data from bulk gyttja samples as a check for reworking in cases where chronostratigraphic markers are absent.Le lac O'Hara (subalpin) et le lac Opabin (alpin) sont situCs immkdiatement en bordure d'une coupe ClevCe de la ligne Continentale de partage des eaux, dans les montagnes Rocheuses centrales du Canada. Des carottes prClevCes dans ces lacs kvklent une stratigraphie homogbne incluant des sCdiments de type gyttja sus-jacents a des skdiments inorganiques clastiques. Les sCdiments de type gyttja sont formCs des tephras de Bridge River (2350 ans Av.P.) et de Mazama (6800 ans Av.P.) et sont sCparCs des sCdiments clastiques sous-jacents par un contact concordant t k s net. Les Bges au radiocarbone obtenus sur les aiguilles de coniferes, extraites directement au-dessus du contact, indiquent que la dkglaciation a procC...

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“…To determine chemical changes that may cause the fluctuations in potential DON bioavailability, we monitored concentrations of the major identifiable DON compounds during the flood: urea and dissolved free and combined amino acids (DFAA and DCAA, respectively). In addition, the fraction of D-enantiomers in amino acids was analyzed, because a high proportion of D-forms in DCAA is suggested to indicate old and refractory organic material (Pollock et al 1977;Mc-Carthy et al 1998;Jørgensen et al 1999).…”

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High DON bioavailability in boreal streams during a spring flood

Stepanauskas

Laudon

Jørgensen³

2000

Limnology & Oceanography

130

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Riverine inputs of nitrogen is an important factor that controls productivity of coastal marine waters. Dissolved organic nitrogen (DON) comprises most of the N in boreal rivers. During spring floods, DON flux may exceed the baseflow flux by several orders of magnitude. However, little is known about the biological availability of spring flood DON and, thus, its potential effect on coastal productivity.We have investigated the dynamics of DON bioavailability and chemical composition during a spring flood in two streams in northern Sweden. Potential bioavailability was determined by employing bacterial regrowth bioassays with brackish medium and a coastal bacterial inoculum. In addition, concentrations of urea and amino acids and the proportion of D-isomers in total dissolved amino acids were analyzed because a high proportion of D-isomers is suggested to indicate old and refractory organic material.During the flood, potential DON bioavailability increased from 19-28% at baseflow to 55-45% during peak flow in the two streams, while DON concentration remained relatively constant. At the end of the flood, bioavailability returned to the baseflow values. Potential DON bioavailability was positively correlated with the concentration of dissolved combined amino acids and the proportion of L-enantiomers of amino acids. However, only 5-18% of DON was identified as urea and free and combined amino acids, suggesting that bacteria also utilized other DON compounds. Our results imply that a major portion of the annual export of labile nitrogen occurred during a few weeks of spring flood.

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Determination of the D and L isomers of some protein amino acids present in soils

Cited by 57 publications

References 19 publications

Amino acids of the murchison meteorite:

Amino acids of the murchison meteorite:

Late Quaternary history of the Lake O'Hara region, British Columbia – an evaluation of sedimentation rates and bulk amino acid ratios in lacustrine records

High DON bioavailability in boreal streams during a spring flood

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