Carbon isotope ratios of amylose, amylopectin and mutant starches

Scott, M. Paul; Jane, Jay‐lin; Soundararajan, M.

doi:10.1016/s0031-9422(99)00271-x

Cited by 14 publications

(10 citation statements)

References 19 publications

(10 reference statements)

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“…Differences in δ 13 C background levels between n -alkanes ( Table 2 ) appeared to depend on the respective chain length and suggest that carbon isotope discrimination occurs during the enzymatic n -alkane biosynthesis by decarbonylase in the plant cuticula. Similar observations were reported for the biosynthesis of lignin [30] and starch [31] in plant tissue. Differential carbon allocation as observed in the plant tissue does not occur in the animal organism due to the absence of ruminal synthesis and degradation of n -alkanes [10], [11].…”

Section: Discussionsupporting

confidence: 89%

Stable Isotope Labeled n-Alkanes to Assess Digesta Passage Kinetics through the Digestive Tract of Ruminants

et al. 2013

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We describe the use of carbon stable isotope (13C) labeled n-alkanes as a potential internal tracer to assess passage kinetics of ingested nutrients in ruminants. Plant cuticular n-alkanes originating from intrinsically 13C labeled ryegrass plants were pulse dosed intraruminally in four rumen-cannulated lactating dairy cows receiving four contrasting ryegrass silage treatments that differed in nitrogen fertilization level (45 or 90 kg nitrogen ha−1) and maturity (early or late). Passage kinetics through the gastrointestinal tract were derived from the δ13C (i.e. the ratio 13C:12C) in apparently undigested fecal material. Isotopic enrichment was observed in a wide range of long-chain n-alkanes (C27–C36) and passage kinetics were determined for the most abundant C29, C31 and C33 n-alkanes, for which a sufficiently high response signal was detected by combustion isotope ratio mass spectrometry. Basal diet treatment and carbon chain length of n-alkanes did not affect fractional passage rates from the rumen (K 1) among individual n-alkanes (3.71–3.95%/h). Peak concentration time and transit time showed a quantitatively small, significant (p≤0.002) increase with carbon chain length. K 1 estimates were comparable to those of the 13C labeled digestible dry matter fraction (3.38%/h; r = 0.61 to 0.71; p≤0.012). A literature review has shown that n-alkanes are not fermented by microorganisms in the rumen and affirms no preferential depletion of 13C versus 12C. Our results suggest that 13C labeled n-alkanes can be used as nutrient passage tracers and support the reliability of the δ13C signature of digestible feed nutrients as a tool to measure nutrient-specific passage kinetics.

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Section: Discussionsupporting

confidence: 89%

Stable Isotope Labeled n-Alkanes to Assess Digesta Passage Kinetics through the Digestive Tract of Ruminants

et al. 2013

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“…However, solubilization by DMSO yielded starch preparations that were depleted in 13 C compared to untreated controls, while samples derived by HCl dissolution and ethanolic precipitation were always 13 C enriched (Table 1). Recently, it has been shown that δ 13 C values of amylose were consistently less negative than those of amylopectin by up to 2.3‰,9 suggesting that HCl and DMSO exhibit different efficiencies in solubilizing amylose and amylopectin.…”

Section: Resultsmentioning

confidence: 99%

“…Native starches from potato ( Solanum tuberosum L.), rice ( Oryza sativa L.) and wheat ( Triticum aestivum L.) were purchased from Merck (Darmstadt, Germany). All starch samples were pre‐washed three times with methanol/chloroform/water (MCW, 12:5:3, v/v/v) to extract traces of lipids and other low‐molecular‐weight substances, and dried before further use 9. Heat‐stable α‐amylase from Bacillus licheniformis was purchased from Sigma‐Aldrich Chemicals (Vienna, Austria).…”

Section: Methodsmentioning

confidence: 99%

Preparation of starch and other carbon fractions from higher plant leaves for stable carbon isotope analysis

Wanek

Heintel

Richter

2001

Rapid Comm Mass Spectrometry

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The measurement of the carbon isotope composition of starch and cellulose still relies on chemical isolation of these water-insoluble plant constituents and subsequent elemental analysis by isotope ratio mass spectrometry (EA/IRMS) of the purified fractions, while delta(13)C values of low-molecular-weight organic compounds are now routinely measured by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Here we report a simple and reliable method for processing milligram quantities of dried plant material for the analysis of the carbon isotope composition of lipids, soluble sugars, starch and cellulose from the same sample. We evaluated three different starch preparation methods, namely (1) enzymatic hydrolysis by alpha-amylase, (2) solubilization by dimethyl sulfoxide (DMSO) followed by precipitation with ethanol, and (3) partial hydrolysis by HCl followed by precipitation of the resulting dextrins by ethanol. Starch recovery for three commercially available native starches (from potato, rice and wheat) varied from 48 to 81% for the techniques based on precipitation, whereas the enzymatic technique exhibited yields between 99 and 105%. In addition, the DMSO and HCl techniques introduced a significant (13)C fractionation of up to 1.9 per thousand, while the carbon isotope composition of native starches analyzed after enzymatic digestion did not show any significant difference from that of untreated samples. The enzymatic starch preparation method was then incorporated into a protocol for determination of delta(13)C signatures of lipids, soluble carbohydrates, starch and crude cellulose. The procedure is based on methanol/chloroform/water extraction of dried and ground leaf material. After recovery of the chloroform phase (lipid fraction), the methanol/water phase was deionized by ion exchange (soluble carbohydrate fraction) and the pellet treated with heat-stable alpha-amylase (starch fraction). The remaining insoluble material was subjected to solvolysis by diglyme (cellulose fraction). The method was shown to be applicable to foliar tissues of a variety of different plant species (spruce, erect brome, maize and soybean).

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“…We did not detect this relationship in our study, but the δ 13 C of starch and total bulk needle material of 1-yearold spruce needles did show a positive correlation to temperature for 2 consecutive years. The best correlation was found for climate data collected during the month before sampling, indicating that starch is a temporal medium-term integrator of δ 13 C. However, the temperature signal is not strongly reflected in the δ 13 C signature and, in the case of starch, could be superimposed by enzyme fractionation (Gleixner et al 1993;Scott et al 1999).…”

Section: Relationship Between δ 13 C and Climatic Factorsmentioning

confidence: 96%

“…2A, B) (Brugnoli et al 1988;Jordan and Mariotti 1998;Duranceau et al 1999). This difference results from isotopic fractionation by enzymes (Scott et al 1999).…”

Section: Relationship Between δ 13 C and Climatic Factorsmentioning

confidence: 99%

The relationship between the stable carbon isotope composition of needle bulk material, starch, and tree rings in Picea abies

et al. 2002

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We investigated the relationship between the δC signal in current-year and 1-year-old needle bulk material, starch extracts, and early- or late-wood in mature spruce trees (Picea abies) to identify the modifying influence of climatic conditions on the different δC signals. Seasonal patterns of δC were determined in total bulk needle material from 1998 to 2000, and in acid soluble starch extracts in 1999 and 2000, and δC values of early- and late-wood were measured for the years 1991-2000. δC of bulk needle material was most enriched in spring with a trend towards depletion in the course of the season. Current-year needles showed a more distinct seasonal pattern in δC compared to 1-year-old needles. Seasonal trends in bulk material and starch were similar, but the highly enriched signal in spring could not be fully explained by the influence of the δC values of starch (weighted with the corresponding starch amounts). δC of starch in 1-year-old needles, and to a lesser extent of current-year needles, correlated with δC of early-wood, indicating a transfer of the isotopic signal. In addition, early-wood δC corresponded weakly to winter precipitation. In the summer, δC of total bulk needle material and starch showed no relation to the late-wood δC signature. Late-wood δC, however, related to global radiation, relative humidity and temperature, with more enriched values corresponding to warmer and drier conditions. We conclude that the signature of early-wood is determined more by biochemical fractionation, e.g. during starch formation, than by climatic conditions, which exert only a minor influence and are reflected in the isotopic signal of late-wood.

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Carbon isotope ratios of amylose, amylopectin and mutant starches

Cited by 14 publications

References 19 publications

Stable Isotope Labeled n-Alkanes to Assess Digesta Passage Kinetics through the Digestive Tract of Ruminants

Stable Isotope Labeled n-Alkanes to Assess Digesta Passage Kinetics through the Digestive Tract of Ruminants

Preparation of starch and other carbon fractions from higher plant leaves for stable carbon isotope analysis

The relationship between the stable carbon isotope composition of needle bulk material, starch, and tree rings in Picea abies

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