Biomedical subjects

C Faustman

Publications and source records attributed to C Faustman.

13 recordsLinked to original sources

PubMed2003

Induction of redox instability of bovine myoglobin by adduction with 4-hydroxy-2-nonenal.

The redox stability of myoglobin (Mb) is compromised by many factors, including lipid oxidation and its products. 4-Hydroxy-2-nonenal (HNE) is an alpha,beta-unsaturated aldehyde derived from the oxidation of omega-6 polyunsaturated fatty acids and is highly reactive and cytotoxic. Our objective was to study potential binding of HNE to Mb and determine how it affects redox stability. OxyMb (0.15 mM) was incubated with HNE (1 mM) at 4, 25, and 37 degrees C at pH 7.4 or 5.6. Samples were analyzed for MetMb formation and by Western blot analyses, LC-MS, LC-MS-MS, circular dichroism (CD), and differential scanning calorimetry (DSC). MetMb formation increased with increasing temperature and was greater at pH 5.6 than at pH 7.4 (P < 0.05). At 37 degrees C, HNE accelerated oxidation at pH 7.4 but not at pH 5.6 (P < 0.05). At both 25 and 4 degrees C, HNE accelerated oxidation at pH 7.4 and 5.6 (P < 0.05). LC-MS revealed the covalent binding of HNE to Mb at both pH values via Michael addition, while Western blot analysis indicated that HNE was bound to histidine (HIS) residues. LC-MS-MS identified six histidine residues of Mb that were readily adducted by HNE, including the proximal (HIS 93) and distal (HIS 64) histidine associated with the heme group. Secondary structure differences between control Mb and Mb incubated with HNE were not detected by CD. However, DSC revealed a decreased T(m) for Mb reacted with HNE at pH 7.4, indicating Mb tertiary structure was altered in a manner consistent with destabilization. These results suggest that HNE accelerates bovine skeletal muscle OxyMb oxidation in vitro by covalent modification at histidine residues.

Aldehydes↗

PubMed2000

Effect of aldehyde lipid oxidation products on myoglobin.

The effects of aldehyde lipid oxidation products on myoglobin (Mb) were investigated at 37 degrees C and pH 7.2. Oxymyoglobin (OxyMb) oxidation increased in the presence of 4-hydroxynonenal (4-HNE) compared to controls (P < 0.05). Preincubation of metmyoglobin (MetMb) with aldehydes rendered the heme protein a poorer substrate for enzymatic MetMb reduction compared to controls, and the effect was inversely proportional to preincubation time; unsaturated aldehydes were more effective than saturated aldehydes (P < 0.05). The order of MetMb reduction as affected by preincubation was control > hexanal > heptanal > octanal > nonanal = decanal = hexenal > heptenal = octenal > nonenal = decenal = 4-HNE (P < 0.05). Preincubation of MetMb with 4-HNE enhanced the subsequent ability of the heme protein to act as a prooxidant in both liposomes and microsomes when compared to controls (P < 0.05); the effect was reduced in microsomes containing elevated concentrations of alpha-tocopherol (P < 0.05). MetMb preincubation with mono-unsaturated aldehydes enhanced the catalytic activity of MetMb to a greater degree than saturated aldehydes (P < 0.05). These results suggest that aldehyde lipid oxidation products can alter Mb stability by increasing OxyMb oxidation, decreasing the ability of MetMb to be enzymatically reduced and enhancing the prooxidant activity of MetMb.

Aldehydes↗

PubMed1999

alpha-tocopherol oxidation in beef and in bovine muscle microsomes.

The oxidation of alpha-tocopherol (TH) in beef was analyzed using a stable isotope dilution capillary gas chromatography-mass spectrometry assay. TH decreased while alpha-tocopherolquinone (TQ) and 2,3-epoxy-alpha-tocopherolquinone (TQE(2)) increased in ground longissimus lumborum (LL) and psoas major (PM) muscles during storage (P < 0.10). In LL steaks, the relative concentrations of TH decreased and TQ and TQE(2) increased in surface samples; changes were less dramatic in deep samples. Deuterated alpha-tocopherolhydroquinone (THQ) standard was not recovered and endogenous THQ was not detected in meat; THQ was measurable in microsomes isolated from PM and incubated in the presence of 2, 2'-azobis(2-amidopropane)HCl (ABAP) or myoglobin. ABAP-challenged microsomes yielded a tocopherol product profile which favored 5, 6-epoxy-alpha-tocopherolquinone (TQE(1)) and TQE(2), while the use of myoglobin as prooxidant resulted in a higher proportion of TQ and THQ. Results demonstrated that concentrations of TH decreased and TQ and TQE(2) increased in meat during storage and are consistent with the peroxy-radical scavenging function of tocopherol.

Animals↗

PubMed1999

alpha,beta-unsaturated aldehydes accelerate oxymyoglobin oxidation.

This study investigates the potential basis for enhancement of oxymyoglobin (OxyMb) oxidation by lipid oxidation products. Aldehydes known to be formed as secondary lipid oxidation products were combined with OxyMb in aqueous solution at 37 degrees C and pH 7.4. Metmyoglobin (MetMb) formation was greater in the presence of alpha,beta-unsaturated aldehydes than their saturated counterparts of equivalent carbon chain length. Additionally, increasing chain length from hexenal through nonenal resulted in increased MetMb formation (P < 0.05). Electrospray ionization mass spectrometry (ESI-MS) revealed that OxyMb incubated with 4-hydroxynonenal (HNE) at pH 7.4 at 37 degrees C yielded myoglobin molecules adducted with one to three molecules of HNE from 0.5 to 2 h of incubation, respectively. A prooxidant effect of HNE was noted at pH 7.4 but was not apparent at pH 5.6 when compared to the control (P < 0.05). This appeared to be due to rapid OxyMb autoxidation at this pH compared to pH 7.4. ESI-MS demonstrated that adduction of HNE to OxyMb occurred at pH 5.6. This research demonstrates that alpha, beta-unsaturated aldehydes accelerate OxyMb oxidation and appear to do so via covalent attachment.

Aldehydes↗

PubMed1998

Beef color update: the role for vitamin E.

Dietary supplementation of livestock with vitamin E results in improved quality of meat subsequently obtained from these animals. The effect is especially noteworthy in cattle, in which the primary effects are delayed discoloration and lipid oxidation. A threshold level of alpha-tocopherol in muscle ensures a detectable effect; dietary strategies for attaining this threshold must consider tocopherol status of cattle arriving at the feedyard and duration and level of supplementation. The alpha-tocopherol concentration in muscle must be determined before proper interpretation of experimental results can be made. Muscles vary in their color stability, and this relative difference is not changed by vitamin E supplementation. Several in vitro models have been used to characterize the interaction between alpha-tocopherol, lipid oxidation, and oxymyoglobin oxidation. Alpha-tocopherol seems to exert its color-stabilizing effect by indirectly delaying oxymyoglobin oxidation via direct inhibition of lipid oxidation. However, recent results demonstrating a protective effect of alpha-tocopherol toward oxymyoglobin in low-oxygen atmospheres indicate that additional mechanisms may exist. A better understanding of the fundamental bases for protection of water-soluble myoglobin by lipid-soluble alpha-tocopherol is needed to optimize this beneficial effect.

Animals↗

PubMed1998

Effects of alpha-tocopherol on metmyoglobin formation and reduction in beef from cattle fed soybean or cottonseed meal diets.

Hereford-Angus crossbred heifers were fed a cottonseed meal-based diet containing gossypol (14 mg free gossypol x kg body wt(-1) x d(-1); CSM), a soybean meal-based diet (SBM), or alpha-tocopherol-supplemented diets (4,036 IU vitamin E x heifer(-1) x d(-1) for 90 d; CSM+E and SBM+E). The effects of diet on color stability and aerobic metmyoglobin reducing ability of beef longissimus lumborum (LL) and psoas major (PM) were evaluated. The CSM containing gossypol did not affect alpha-tocopherol concentration, a* value, or hue angle value of beef muscles obtained from control or vitamin E-supplemented cattle compared to their SBM counterparts. Vitamin E supplementation increased endogenous alpha-tocopherol concentrations and color stability in LL and PM muscles compared with controls from either diet (P < .05). In the aerobic metmyoglobin reducing ability study, LL and PM muscles were stored in 1% O2:99% N2 (a pigment-oxidizing atmosphere) for 48 h and subsequently stored aerobically for an additional 48 h. Within the LL, alpha-tocopherol supplementation delayed metmyoglobin formation in LL exposed to 1% O2 (P < .05). Within the PM, no differences in metmyoglobin formation were found between controls and vitamin E treatments in SBM or CSM diets. Relative aerobic metmyoglobin reduction was the same (P > .05) in LL and PM muscles within SBM or CSM diets for control and vitamin E treatments. Alpha-tocopherol did not seem to affect metmyoglobin aerobic reducing ability in LL and PM muscles.

Animals↗

PubMed1998

Effect of Pseudomonas fluorescens on beef discoloration and oxymyoglobin oxidation in vitro.

The relationship between bacterial growth and oxymyoglobin oxidation in vitro and in meat was studied. In the in vitro study, oxymyoglobin was combined with Pseudomonas fluorescens or sterile nutrient broth (control) in an airtight vessel. P. fluorescens samples showed greater metmyoglobin formation and oxygen consumption than controls. The P. fluorescens population in the reaction vessels was correlated with metmyoglobin formation (r = 0.85, P < 0.05) and oxygen consumption (r = 0.91, P < 0.05). When P. fluorescens and oxymyoglobin were combined in an airtight vessel, reducing the headspace from 13 ml and 9 ml to 3 ml resulted in greater metmyoglobin formation (P < 0.05). In the meat study, beef cores prepared from longissimus lumborum were inoculated with P. fluorescens (10(7) CFU/cm2) or sterile peptone water (control), packaged under 1% O2 (+99% N2), air, or 100% O2 and stored at 4 degrees C. Inoculated beef cores showed higher bacterial loads and metmyoglobin formation than their respective controls during 10 h storage in 1% O2, 3 days in air, and 7 days in 100% O2 (P < 0.05). This finding indicated that P. fluorescens could accelerate beef discoloration. Overall, studies demonstrated that oxygen consumption concomitant with P. fluorescens growth decreased partial oxygen pressure, which accelerated oxymyoglobin oxidation.

Animals↗

PubMed1997

Rapid estimation of spoilage bacterial load in aerobically stored meat by a quantitative polymerase chain reaction.

We report a quantitative PCR which utilizes primers from a conserved 23S rDNA sequence identified in nine different spoilage bacteria commonly present in meat. The PCR detected the spoilage bacteria by amplifying a specific 207 bp sequence from their chromosomal DNA. Quantification of PCR product by electrochemiluminescence revealed that the concentration of the amplified product was dependent on cycle number and the initial number of bacteria present in the sample. Statistical analysis of the results indicated a correlation coefficient of 0.94 (P < 0.001) between aerobic plate count and QPCR luminosity units.

Bacteria↗

PubMed1996

Partial characterization of ovine skeletal muscle proteoglycans and collagen.

Ovine longissimus dorsi and biceps femoris muscles were analyzed for proteoglycan content, collagen and lysine aldehyde-derived collagen crosslinking concentrations at 2-4 days, six-month-old, and six-year-old stages of development. Tissue extracted proteoglycan molecular sieve distribution on a Sephacryl S-200HR column revealed two proteoglycan populations with estimated relative molecular weight ranges of 200,000 to 250,000 daltons and 23,000 to 70,000 daltons. The molecular sieve distribution was similar between the two muscles within a developmental age, but changed as a function of developmental age. Primary culture from both the longissimus dorsi and biceps femoris muscle liberated proteoglycans into the culture medium. In contrast to the tissue extracted proteoglycans, at the six-year-old stage of development, culture medium liberated proteoglycan Sephacryl S-200HR molecular sieve distribution differed between the two muscles. In both the tissue extracted and medium liberated proteoglycans at all developmental stages, nitrous acid deamination demonstrated the presence of heparan sulfate. Immunoblot analysis of the tissue extracted proteoglycans indicated the presence of decorin at each developmental stage. Longissimus dorsi and biceps femoris collagen concentrations (5.13 +/- 0.9 vs. 5.53 +/- 1.5%, respectively) and crosslink concentrations (0.07 +/- 0.01 moles HP/mole collagen) were initially similar between the two muscles; however, by six-months the muscles differed in both collagen concentration (1.72 +/- 0.5 and 2.53 +/- 0.7%, respectively) and crosslinking (0.24 +/- 0.02 and 0.27 +/- 0.03 moles HP/mole collagen, respectively). At six years of age, both the longissimus dorsi and biceps femoris exhibited slightly elevated collagen concentrations (2.49 and 3.05%, respectively) while crosslinking values were decreased relative to values at six-months of age (0.11 +/- 0.01 and 0.18 +/- 0.01 moles HP/mole of collagen, respectively). The results from this study indicate that skeletal muscle proteoglycans and collagen show developmental changes, which suggests that they are subject to developmental regulation.

Animals↗

PubMed1995

Supranutritional administration of vitamins E and C improves oxidative stability of beef.

Vitamins E and C are important antioxidants in animals. Their antemortem activity continues to function in postmortem muscle (meat), where they have a critical role in maintaining quality in the food product. Dietary supplementation of vitamin E, and intravenous infusion of vitamin C immediately before harvest, are efficacious techniques for increasing the concentration of these vitamins in beef skeletal muscle. Meat with elevated levels of either and probably both of these antioxidant vitamins possesses greater stability of oxymyoglobin and lipid, which results in less discoloration and rancidity, respectively. A model is proposed for the redox relationships between myoglobin and phospholipid in beef with emphasis on vitamins E and C. Antemortem nutritional intervention appears to be a promising approach for improving the quality of fresh meat products subsequently obtained from livestock.

Animal Nutritional Physiological Phenomena↗

PubMed1994

Carcass composition of "bob" and "special-fed" veal and its prediction.

Percentage of lean, fat, and bone were determined in 18 bob veal (BV) and 28 special-fed veal (SFV) carcasses. Carcasses were subjected to a set of visual conformation scores and a variety of physical measurements. No significant differences were found regarding carcass percentage of lean, fat, and bone within the three BV weight groups (P > .05). On average, SFV were 12% fatter than BV and did not have a greater percentage of lean (P > .05), except for SFV carcasses weighing 88.2 to 97.7 kg. Bob veal had less fat (internal, external, and intermuscular) and a higher bone percentage than SFV (P < .05). The round and shoulder primals had the greatest proportion of lean in both the BV and SFV carcasses. Bob veal carcasses had an average conformation score of average Good and SFV carcasses had an average conformation score of average Choice. In addition, a parsimonious subset of variables was identified for predicting total percentage of lean (TPLEAN) for both BV and SFV separately, using "stepwise" regression model building procedures. For BV, all four identified predictor variables were subjective conformation scores (i.e., muscling, appearance, leg thickness, loin-back plumpness) (R = .73, P < .03). For SFV, four predictor variables were also identified: kidney and pelvic fat, fat thickness, carcass length, and lateral thickness (R = .61, P < .03). Although both regression equations were significant predictors of TPLEAN, confidence limits for predicting future TPLEAN value were wide relative to the variation in the actual TPLEAN values. Thus, the practical utility of the regression equations is limited.

Adipose Tissue↗

PubMed1993

Pork quality and the expression of stress protein Hsp 70 in swine.

The expression of heat shock protein with a molecular weight of 70 kDa (Hsp 70) in porcine tissue and its potential relationship to stress susceptibility was studied. Twelve pigs, four of each genotype (NN, Nn, and nn) for halothane sensitivity were slaughtered. At 45 min postmortem, several tissues (liver, kidney, spleen, skeletal and cardiac muscle, and adrenal gland) were sampled for Hsp 70 analysis. At 24 h postmortem, longissimus and semimembranosus muscle were sampled for assessment of meat quality. Water-holding and water-binding capacity, color, and protein denaturation of samples from halothane-positive animals indicated that these animals had been stressed. Homozygous nn pigs demonstrated a lower pH45 and higher L-value at 48 h than their NN and Nn counterparts (P < .05). The longissimus, but not semimembranosus, muscle of nn pigs demonstrated lower water-holding capacity and greater protein denaturation than that of NN or Nn pigs (P < .05). The water-binding capacity of both longissimus and semimembranosus was less in nn than in Nn or NN pork (P < .05). Using one-dimensional PAGE and Western blotting, Hsp 70 was shown to be present in all tissues examined. With two-dimensional PAGE followed by blotting, the presence of the cognate and inducible form of Hsp 70 was investigated. There did not seem to be a relationship between stress (based on meat quality) and expression of either form of Hsp 70.

Analysis of Variance↗

PubMed1991

The effect of cattle breed and muscle type on discoloration and various biochemical parameters in fresh beef.

The levels of nonprotein sulfhydryls (NPSH), glutathione disulfide (GSSG), nicotinamide adenine dinucleotide (NAD), hypoxanthine (Hx), xanthine (X) and the extent of lipid (TBA) and pigment oxidation (%MetMb) were determined in longissimus and gluteus medius muscles during storage at 4 degrees C. Muscles were obtained from Holstein and crossbred beef steers. Holstein beef displayed higher values for %MetMb, NAD and TBA and lower values for GSSG and Hx than crossbred beef (P less than .05). These two breed groups did not differ (P greater than .05) in X and NPSH. During storage, GSSG, Hx, X, %MetMb, GSSG/NPSH ratio and TBA value all increased, whereas NAD and NPSH decreased. Compared to the longissimus, the gluteus medius had greater %MetMb, TBA value, GSSG/NPSH ratio and Hx but lower (P less than .05) NAD and NPSH. Differences between Holstein and crossbred animals and between gluteus medius and longissimus muscles in meat color stability may be dependent on inherent metabolic differences.

Animals↗