![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
4 Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, NE 68583-0806; 5 Edward A. Doisy Department of Biochemistry and Molecular Biology and 6 Department of Pharmacological and Physiological Sciences, Saint Louis University School of Medicine, St. Louis, MO 63104; 7 School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0118; and 8 Department of Food Science and Technology, University of Nebraska, Lincoln, NE 68583-0919
* To whom correspondence should be addressed. E-mail: jzempleni2{at}unl.edu.
 |
ABSTRACT |
|---|
 TOP ABSTRACT IntroductionMethodsResultsDiscussionLITERATURE CITED |
|---|
|
Introduction |
|---|
|
TOPABSTRACTIntroductionMethodsResultsDiscussionLITERATURE CITED |
|---|
A fundamental problem associated with previous studies on lifespan extension by energy restriction in Drosophila is that energy restriction was achieved by diluting all nutrients present in food (6,7). Therefore, it was not possible to identify individual nutrients that may account for lifespan extension in Drosophila. Here, we overcame this limitation by testing the effects of the deficiency of a single nutrient (the water-soluble vitamin biotin) on stress resistance and lifespan in flies. Biotin was selected as a model based on the following lines of reasoning. First, previous work showed that short-term biotin deficiency (11 d) is associated with altered stress resistance: biotin-deficient (BD)9 male Drosophila had a 40% increase in resistance to oxidative stress as judged by survival times (8). Second, biotin affects signaling pathways that relate to stress resistance and survival pathways (9). For example, biotin deficiency enhances the nuclear translocation of nuclear factor-
B and the expression of anti-apoptotic genes in eukaryotes (10). Third, biotin is covalently attached to histones H2A, H3, and H4 (11–13), suggesting that biotin might influence longevity through epigenetic regulation of gene expression patterns. Histone biotinylation is implicated in heterochromatin structures, gene silencing, DNA repair, and mitotic chromatin condensation (14–16). Biotinylation of histones is mediated by holocarboxylase synthetase (HCS) (17), which is a chromosomal protein (9). Camporeale et al. (9,18) demonstrated that HCS deficiency affects gene expression patterns, lifespan, and heat resistance in Drosophila.
Here, we tested the hypothesis that feeding a BD diet for >10 generations increases stress resistance and lifespan in Drosophila. Specifically, we tested whether: 1) biotin deprivation is associated with increased lifespan in Drosophila; 2) biotin deficiency is associated with altered fecundity; 3) alterations in lifespan are due to a specific resistance to biotin deficiency or to a global resistance to stress; 4) behavioral changes occur in response to biotin deprivation; and 5) changes in biotin-dependent phenotypes are associated with loss of specific histone biotinylation isoforms.
|
Methods |
|---|
|
TOPABSTRACTIntroductionMethodsResultsDiscussionLITERATURE CITED |
|---|
D. melanogaster were obtained from a laboratory-adapted population of a nonselected wild-type strain of Drosophila. The laboratory population was originally established from a natural Drosophila population and allowed to adapt to laboratory conditions through a large cage where the population size was typically over 10,000. This large size preserved natural genetic variation.
Drosophila husbandry
The flies were fed 1 of 2 diets, control or BD. Fly medium was prepared as described previously (19) and rendered BD by the addition of 80 g spray-dried egg white (EW) per 1 L of diet (8). Raw EW contains the protein avidin, which has a high affinity for biotin (20). Avidin-bound biotin is unavailable for absorption (8). For this reason, the flies grown on this medium were denoted BD. Because 80 g EW contained 
56 g of protein, protein-matched control diets were prepared by substituting 56 g bovine serum albumin for EW. Variations in amino acid composition between these 2 proteins were moderate (Supplemental Table S1) (21,22). In addition, the yeast powder used in the preparation of fly diets contained 400 g protein/kg powder (23). Given that 1 g of EW protein or bovine serum albumin were added per 2 g of yeast powder during preparation of diets (8,19), the variation introduced by EW protein and serum albumin in regard to amino acid composition was small. The concentration of bioavailable biotin in both diets was confirmed by avidin binding assay (8). The BD diet contained 0.22 ± 0.09 nmol/L bioavailable biotin; the control diet contained 32 ± 0.3 nmol/L bioavailable biotin. Dietary biotin was routinely monitored throughout this study. Flies were fed these diets for multiple generations, as described below.
In some experiments, it was important to distinguish between short-term effects of biotin deficiency on gene expression and stress resistance and effects of adaptation to biotin deficiency over multiple generations on gene expression and stress resistance. Therefore, a 3rd group of flies was fed a BD diet for 12 generations and then switched to a control diet for 2 generations. These flies were denoted F12+2. Flies were housed in 60- x 130-mm polypropylene bottles at 25°C and kept on a 12-h-dark/-light cycle. A minimum of 500 parents were kept for each generation. Flies were collected randomly for stress and longevity experiments; each experiment was performed using 25 flies per repeat (25- x 95-mm polystyrene vials) for a total of 4 repeats per diet group unless noted otherwise.
Lifespan
Lifespan experiments were conducted as described previously (8). Flies were kept on biotin-normal medium while monitoring lifespan.
Stress experiments
Resistance to heat stress, starvation, and DNA-damaging agents were evaluated as follows. First, flies were exposed to temperature stress (34°C) as previously described and survival was monitored at timed intervals (9). Second, flies were exposed to the following starvation stresses: 1) no access to food or water (denoted starved/dehydrated flies); 2) access to water through a plastic foam plug that was moistened every 24 h (denoted starved flies); and 3) access to 2% agar/water medium, a starvation medium commonly used in Drosophila experiments (denoted starved agar flies); starved agar flies were transferred to fresh vials every 72 h. Fly survival was monitored at timed intervals (2 h for starved/dehydrated, 4 h for starved, 8 h for starved agar flies) until all flies died. Third, flies were exposed to hydroxyurea to evaluate their resistance to DNA damage (24). In these experiments, young adult flies (6 males and 6 females) were fed BD or biotin-normal diets containing 5, 7, or 11 mmol/L of hydroxyurea; controls were fed hydroxyurea-free medium (4 repeats/group). Flies were allowed to lay eggs for 48 h. Parent flies were discarded and progeny were counted upon eclosion.
DNA microarray
Candidate genes that mediate stress resistance were identified using the Drosophila Genome 2.0 Array (Affymetrix). RNA was extracted from 100 flies (9). Microarray analyses were conducted at the Genomics Core Research Facility, University of Nebraska-Lincoln as described (9). Affymetrix GeneChip operating software 1.4 was used for normalization and analysis of microarray data. In these experiments, F12+2 males and females were compared with biotin-normal males and females (controls), respectively. BD flies were not included in microarray analysis, because short-term effects of biotin deficiency could have confounded expression data. Expression changes were considered dependent on biotin deprivation if their expression increased by at least 100% or decreased by at least 50% in F12+2 flies compared with biotin-normal controls.
Fertility studies
Potential effects of population density and biotin deprivation on fertility were monitored using 2 different methods. First, 6 virgin females were mated with 6 males and allowed to lay eggs for 24 h; the small number of parents resulted in a low population density for both BD and control flies. Parents were removed and offspring was counted upon eclosion. Next, we determined whether the biotin status of parents or the biotin concentration in media during egg and larval development were more crucial for fecundity. In these experiments, 90 eggs were collected in 8 replicates (720 total eggs) from BD flies and biotin-normal controls; the eggs were transferred to both BD and control diets in all possible permutations (4 repeats at 90 eggs each): eggs from BD parents to BD diet; BD parents to control diet; control parents to BD diet; and control parents to control diet. Emerging adults were counted and transferred to a fresh vial of the diet from which they had eclosed; offspring of these flies were used to conduct stress experiments with heat and hydroxyurea.
Body composition
Total protein levels of BD and control flies were measured by extracting the homogenate of 100 male and 100 female flies with 300 µL PBS. Samples were centrifuged (10 x g; 1 min) and the supernatant was analyzed using the bicinchoninic acid assay (Pierce) according to the manufacturer's procedures. Total lipids were quantified in pools of flies that were homogenized in the absence of PBS (n = 4 repeats, 150 male and female each). Total fat was quantified using the SafTest PerCent Fat kit (MP Biochemicals) according to the manufacturer's instructions.
Behavioral analysis
For all behavioral assays, male and female flies were collected as newly eclosed virgin adults and aged 5 d before assay.
Geotaxis. A single fly was placed into a 100- x 30-mm vial marked with a line drawn horizontally 8 cm above the surface. The flies were simultaneously tapped to the surface and given 10 s to demonstrate their normal negative geotaxis by migrating against the natural force of gravity. Flies crossing the 8-cm line within 10 s were considered normal (e.g. negatively geotactic).
Righting. A single fly was aspirated into a 23- x 75-mm polystyrene vial, allowed to recover from aspiration for 30 s, and subjected to a brief, 5-s mechanical shock by vortexing (25). The fly was tapped into a supine position and given 10 s to right from this position. If the fly righted within 10 s, the response was scored as positive. If the fly failed to right within 10 s, the response was scored as negative.
Locomotion. General activity for adult animals was assessed using a simple locomotor paradigm (26). A single fly was aspirated into a 60-mm petri dish marked with a grid of 1-cm squares, allowed to recover for 30 s, and locomotor activity was observed for the first 2 (exploratory locomotion) and last 2 min of a 15-min period (basal locomotion). The number of grid lines crossed during each observation period was recorded.
Metabolite profiles
Intermediary metabolites were measured as previously described (27). Briefly, 10 flies were homogenized in 400 µL water and to the full volume was added 1.6 mL acetone. Samples were chilled and centrifuged. The supernatant was decanted into vials prepared with 11 stable isotope-labeled internal standards (500 nmol/L d3 creatine; 10 nmol/L d3 methylmalonic acid; 100 nmol/L each of the following: 13C3 lactate, 13C3 pyruvate, d3 serine, d5 phenylalanine, 15N2 orotate, d4 sebacic acid, 13C6 glucose, d6 inositol, and d5 tryptophan). After 20 µL of triethylamine-trifluoroacetate (custom made liquid salt) was added to the supernatants, the samples were heated to 70°C under a nitrogen stream. As volume was reduced, acetonitrile was added until a constant volume was reached. Pellets were resuspended in methylene chloride and reduced to constant volume. The entire residue was suspended in 150 µL N-methyl-N-trimethylsilyltrifluoracetamide (Sigma), sealed under a Teflon septum, and heated under nitrogen at 70°C for 1 h. Then, 1 µL of the soluble portion was injected into an Agilent 5975 GCMS. A splitless glass insert was used and purge gas was turned off for 1 min. The injection temperature was 250°C. A 30-m DB5 capillary column (film thickness 0.5 µm, i.d. 0.32 mm) was used with a temperature program of: 80–130°C at 4°C/min, 130–200°C at 6°C/min, and 200–285°C at 12 °C/min with holds of 1 min at 80°C and 10 min at 285°C for a total run time of 42.5 min. The mass spectrometer, in EI+ mode, scanned from 50 to 650 atomic mass units every 1.95 s with 0.05-s interscan time after a 3.5-min delay. Metabolite concentrations were determined from previously calculated 5-point standard curves.
Protein biotinylation
Histone extracts from whole fly homogenates were prepared using 0.25 mol/L HCl at 4°C overnight as described (28). Denatured proteins were removed by centrifugation and acid-soluble histones in the supernatant were precipitated with trichloracetic acid (1.2 mol/L final concentration). Histones were washed with acetone and dissolved in 8 mol/L urea. Histones were resolved by gel electrophoresis (11) and biotinylated histones were detected using streptavidin-peroxidase as a probe for biotin and 2 specific antibodies for biotinylated lysine residues, K9 biotinylated H3 (K9BioH3) and K18 biotinylated H3 (K18BioH3) (9,14).
Biotin also serves as a coenzyme for acetyl-CoA carboxylase 
, acetyl-CoA carboxylase ß, 3-methylcrotonyl-CoA carboxylase, propionyl-CoA carboxylase, and pyruvate carboxylase (29). We quantified the abundance of biotinylated carboxylases in BD and biotin-normal males and females. Briefly, 100 flies were homogenized as described (8) and proteins (100 µg) were resolved using 4–8% Tris-acetate gels (Invitrogen). Transblots were probed with streptavidin peroxidase (30).
Statistics
Homogeneity of variances among groups was tested using Bartlett's test (31). If variances were heterogeneous, data were log-transformed before further statistical analysis. Significance of differences among diet groups or generations were tested by 1-way ANOVA. Fisher's protected least significant difference procedure was used for post hoc testing (31). For pairwise comparisons, the paired t test was used to determine significance of differences (32). Gender effects were not tested. We used StatView 5.0.1 (SAS Institute) to perform all calculations. Differences were considered significant if P < 0.01. Data are expressed as means ± SD.
|
Results |
|---|
|
TOPABSTRACTIntroductionMethodsResultsDiscussionLITERATURE CITED |
|---|
-chains of methylcrotonyl-CoA carboxylase and propionyl-CoA carboxylase comigrate as 1 single band and that acetyl-CoA carboxylase was barely detectable in any of the treatment groups. F12+2 females and males lived longer than biotin-normal controls (Table 1).
|
|
|
|
Behavioral changes. BD flies were significantly more active than biotin-normal controls. Results from the locomotion studies showed that BD males and females displayed increased locomotion relative to biotin-normal, gender-matched controls (Fig. 4). BD flies displayed normal righting and geotactic abilities, suggesting that the increased locomotor activity in BD flies is a specific response.
|
Body composition. The weight of BD female flies was significantly higher (1.7 ± 0.05 mg/fly) than biotin-normal females (1.3 ± 0.01 mg/fly), as was the weight of BD males (0.9 ± 0.03 mg/fly) compared with biotin-normal males (0.8 ± 0.01 mg/fly) (P < 0.01; n = 3 repeats at 150 flies each). Body composition analysis revealed that BD females had 13 ± 3% less fat than biotin-normal females and that BD males had 21 ± 4% less fat than biotin-normal males. In contrast, BD females contained 0.07 ± 0.02 mg protein more per fly compared with biotin-normal females and BD males contained 0.04 ± 0.01 mg protein more compared with biotin-normal males (P < 0.01; n = 4 repeats at 150 flies each).
Effects of population density on fertility and stress resistance. Flies maintained on BD medium exhibited increased fertility. While evaluating the hydroxyurea stress experiment, we observed a greater number of BD adults eclosed from hydroxyurea-free controls compared with biotin-normal controls (Fig. 2). To ensure that population density was not a confounder in the hydroxyurea stress experiment, we conducted a population-controlled experiment. Greatest survival to adulthood was observed when eggs from BD parents were transferred to a BD or control diet (Fig. 5), confirming the above findings. Survival to adulthood decreased significantly if eggs were obtained from biotin-normal parents.
|
|
|
|
|
|
Discussion |
|---|
|
TOPABSTRACTIntroductionMethodsResultsDiscussionLITERATURE CITED |
|---|
We hypothesize that effects of biotin deprivation on stress resistance and lifespan might have been caused by epigenetic events. The rationale for our hypothesis is that the BD flies that originally exhibited increased stress resistance and longevity did not maintain this resistance during the population density studies, thereby ruling out a genetic effect. Instead, they began to gradually lose their resistance (documented in Fig. 4), which suggests that metastable patterns of differential gene expression may be playing a key role. Further analysis suggests a role for differential histone biotinylation. Previous studies have shown that short-term effects of biotin deficiency did not affect histone biotinylation (8). However, our studies show that BD flies had significantly decreased histone biotinylation and carboxylase biotinylation after 11 generations of biotin deficiency compared with biotin-normal controls (Figs. 1,7). These results indicate that long-term biotin deprivation leads to modifications in nuclear and cytoplasmic proteins, although the respective contributions of these modifications to the stress resistance and longevity phenotypes are still unknown. On the other hand, the reported effects could also be attributed to a gene-by-environment interaction. Therefore, when the BD flies are exposed to an environment with ample biotin, the increased stress resistance and longevity disappear.
Posttranslational modifications of histones play important roles in chromatin structure and genomic stability. Histone biotinylation is mediated by HCS (17) and perhaps biotinidase in humans (35). Evidence suggests that biotinidase may mediate debiotinylation of histones (36) in addition to acting as a histone biotinyl transferase (35). For example, biotinylation of histones is decreased in HCS-deficient human fibroblasts (13,17). Camporeale et al. (9) showed that HCS is a chromosomal protein in Drosophila and is a direct effector of histone biotinylation in chromatin, which is consistent with our findings that BD flies had decreased biotinylated histones. The data also support findings that reduced histone biotinylation, and not reduced biotinylated carboxylases, are associated with stress resistance (18).
|
FOOTNOTES |
|---|
2 Author disclosures: E. M. Smith, J. T. Hoi, J. C. Eissenberg, J. D. Shoemaker, W. S. Neckameyer, A. M. Ilvarsonn, L. G. Harshman, V. L. Schlegel, and J. Zempleni, no conflicts of interest.
3 Supplemental Tables 1–5 are available with the online posting of this paper at jn.nutrition.org.
9 Abbreviations used: BD, biotin deficient; EW, egg white; F12+2, flies fed BD diets for 12 generations then transferred to control diets for 2 generations; HCS, holocarboxylase synthetase; K9BioH3, K9-biotinylated histone H3; K18BioH3, K18-biotinylated histone H3.
Manuscript received 15 May 2007. Initial review completed 12 June 2007. Revision accepted 20 June 2007.
|
LITERATURE CITED |
|---|
|
TOPABSTRACTIntroductionMethodsResultsDiscussionLITERATURE CITED |
|---|
1. Salmon AB, Murakami S, Bartke A, Kopchick J, Yasumura K, Miller RA. Fibroblast cell lines from young adult mice of long-lived mutant strains are resistant to multiple forms of stress. Am J Physiol Endocrinol Metab. 2005;289:E23–9.
2. Helfand SL, Rogina B. Genetics of aging in the fruit fly, Drosophila melanogaster. Annu Rev Genet. 2003;37:329–48.[Medline]
3. Norry FM, Loeschcke V. Heat-induced expression of a molecular chaperone decreases by selecting for long-lived individuals. Exp Gerontol. 2003;38:673–81.[Medline]
4. Chippindale AK, Leroi AM, Kim SB, Rose MR. Phenotypic plasticity and selection in Drosophila life-history evolution. I. Nutrition and the cost of reproduction. J Evol Biol. 1993;6:171–93.
5. Phelan JP, Rose MR. Caloric restriction increases longevity substantially only when the reaction norm is steep. Biogerontology. 2006;7:161–4.[Medline]
6. Mair W, Piper MD, Partridge L. Calories do not explain extension of life span by dietary restriction in Drosophila. PLoS Biol. 2005;3:e223.[Medline]
7. Wu Q, Zhang Y, Xu J, Shen P. Regulation of hunger-driven behaviors by neural ribosomal S6 kinase in Drosophila. Proc Natl Acad Sci USA. 2005;102:13289–94.
8. Landenberger A, Kabil H, Harshman LG, Zempleni J. Biotin deficiency decreases life span and fertility but increases stress resistance in Drosophila melanogaster. J Nutr Biochem. 2004;15:591–600.[Medline]
9. Camporeale G, Giordano E, Rendina R, Zempleni J, Eissenberg JC. Drosophila holocarboxylase synthetase is a chromosomal protein required for normal histone biotinylation, gene transcription patterns, lifespan and heat tolerance. J Nutr. 2006;136:2735–42.
10. Rodriguez-Melendez R, Schwab LD, Zempleni J. Jurkat cells respond to biotin deficiency with increased nuclear translocation of NF-B, mediating cell survival. Int J Vitam Nutr Res. 2004;74:209–16.[Medline]
11. Camporeale G, Shubert EE, Sarath G, Cerny R, Zempleni J. K8 and K12 are biotinylated in human histone H4. Eur J Biochem. 2004;271:2257–63.[Medline]
12. Chew YC, Camporeale G, Kothapalli N, Sarath G, Zempleni J. Lysine residues in N- and C-terminal regions of human histone H2A are targets for biotinylation by biotinidase. J Nutr Biochem. 2006;17:225–33.[Medline]
13. Kobza K, Camporeale G, Rueckert B, Kueh A, Griffin JB, Sarath G, Zempleni J. K4, K9, and K18 in human histone H3 are targets for biotinylation by biotinidase. FEBS J. 2005;272:4249–59.[Medline]
14. Stanley JS, Griffin JB, Zempleni J. Biotinylation of histones in human cells: effects of cell proliferation. Eur J Biochem. 2001;268:5424–9.[Medline]
15. Kothapalli N, Camporeale G, Kueh A, Chew YC, Oommen AM, Griffin JB, Sarath G, Zempleni J. Biological functions of biotinylated histones. J Nutr Biochem. 2005;16:446–8.[Medline]
16. Camporeale G, Oommen AM, Griffin JB, Sarath G, Zempleni J. K12-biotinylated histone H4 marks heterochromatin in human lymphoblastoma cells. J Nutr Biochem. In press 2007.
17. Narang MA, Dumas R, Ayer LM, Gravel RA. Reduced histone biotinylation in multiple carboxylase deficiency patients: a nuclear role for holocarboxylase synthetase. Hum Mol Genet. 2004;13:15–23.
18. Camporeale G, Zempleni J, Eissenberg JC. Susceptibility to heat stress and aberrant gene expression patterns in holocarboxylase synthetase-deficient Drosophila melanogaster are caused by decreased biotinylation of histones, not of carboxylases. J Nutr. 2007;137:885–9.
19. Chapman T, Partridge L. Female fitness in Drosophila melanogaster: an interaction between the effect of nutrition and of encounter rate with males. Proc R Soc Lond B Biol Sci. 1996;263:755–9.[Medline]
20. Green NM. Avidin. Adv Protein Chem. 1975;29:85–133.[Medline]
21. Posati LP, Orr ML. Composition of foods: dairy and egg products, raw-processed-prepared [monograph on the Internet]. 1976 [cited 6/12/2007]. Available from: http://albumen.stanford.edu/library/c20/posati.html
22. Stein WH, Moore S. Amino acid composition of ß-lactoglobulin and bovine serum albumin. J Biol Chem. 1949;178:79–91.
23. Ingledew WM, Langille LA, Menegazzi GS, Mok MH. Spent brewers yeast: analysis, improvement, and heat processing considerations [monograph on the Internet]. 1977 [cited 2007 June 12]. Available from: http://www.mbaa.com/TechQuarterly/Abstracts/1977/tq77ab06.htm
24. Radcliffe CM, Silva EA, Campbell SD. A method for assaying the sensitivity of Drosophila replication checkpoint mutants to anti-cancer and DNA-damaging drugs. Genome. 2002;45:881–9.[Medline]
25. Pavlidis P, Tanouye MA. Seizures and failures in the giant fiber pathway of Drosophila bang-sensitive paralytic mutants. J Neurosci. 1995;15:5810–9.[Abstract]
26. Neckameyer WS, Cooper RL. GABA transporters in Drosophila melanogaster: molecular cloning, behavior, and physiology. Invert Neurosci. 1998;3:279–94.[Medline]
27. Shoemaker JD, Elliott WH. Automated screening of urine samples for carbohydrates, organic and amino acids after treatment with urease. J Chromatogr. 1991;562:125–38.[Medline]
28. Kang HL, Benzer S, Min KT. Life extension in Drosophila by feeding a drug. Proc Natl Acad Sci USA. 2002;99:838–43.
29. Camporeale G, Zempleni J. Biotin. In: Bowman BA, Russell RM, editors. Present knowledge in nutrition. 9th ed. Washington: International Life Sciences Institute; 2006. p. 314–26.
30. Manthey KC, Griffin JB, Zempleni J. Biotin supply affects expression of biotin transporters, biotinylation of carboxylases, and metabolism of interleukin-2 in Jurkat cells. J Nutr. 2002;132:887–92.
31. SAS Institute. StatView Reference. 3rd ed. Cary (NC): SAS Publishing; 1999.
32. Griffin JB, Zempleni J. Biotin deficiency stimulates survival pathways in human lymphoma cells exposed to antineoplastic drugs. J Nutr Biochem. 2005;16:96–103.[Medline]
33. Mock DM, Henrich CL, Carnell N, Mock NI. Indicators of marginal biotin deficiency and repletion in humans: validation of 3-hydroxyisovaleric acid excretion and a leucine challenge. Am J Clin Nutr. 2002;76:1061–8.
34. Mock N, Malik M, Stumbo P, Bishop W, Mock D. Increased urinary excretion of 3-hydroxyisovaleric acid and decreased urinary excretion of biotin are sensitive early indicators of decreased status in experimental biotin deficiency. Am J Clin Nutr. 1997;65:951–8.
35. Hymes J, Fleischhauer K, Wolf B. Biotinylation of histones by human serum biotinidase: assessment of biotinyl-transferase activity in sera from normal individuals and children with biotinidase deficiency. Biochem Mol Med. 1995;56:76–83.[Medline]
36. Ballard TD, Wolff J, Griffin JB, Stanley JS, van Calcar S, Zempleni J. Biotinidase catalyzes debiotinylation of histones. Eur J Nutr. 2002;41:78–84.[Medline]
This article has been cited by other articles:
|
|
 |
|
  R. Rodriguez-Melendez and J. Zempleni Nitric Oxide Signaling Depends on Biotin in Jurkat Human Lymphoma Cells J. Nutr., March 1, 2009; 139(3): 429 - 433. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Zempleni, M. Gralla, G. Camporeale, and Y. I. Hassan Sodium-Dependent Multivitamin Transporter Gene Is Regulated at the Chromatin Level by Histone Biotinylation in Human Jurkat Lymphoblastoma Cells J. Nutr., January 1, 2009; 139(1): 163 - 166. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
