Biotin Metabolism Research Articles

24. Differential Expression Of Salivary Microrna In Anorexia Nervosa And Anxiety Disorders

Micro ribonucleic acids (miRNAs) regulate protein translation throughout the human body, influencing diverse processes such as brain development and metabolism. Brain to saliva transfer of miRNAs may occur through the cranial nerves, glymphatic drainage or perfusion of the salivary glands. They are altered in psychiatric conditions, such as depression, but have not been studied in anorexia nervosa (AN), a disorder with both psychiatric and metabolic features. The purpose of this study was to identify salivary miRNAs “altered” in AN that may offer diagnostic and therapeutic targets. Participants were females, age 11-21 years, with: 1) restrictive-type AN, at the outset of partial hospitalization treatment; 2) anxiety (AX); and 3) healthy controls (HC). Morning pre- and post-prandial salivary samples were collected. RNA was quantified using high throughput sequencing. Partek Flow was used to align mature and premature miRNAs with the human genome. Significance analysis of microarray (SAM) identified individual miRNAs with differences between 20 AN, 20 AX and 18 HC samples. Variable importance projection (VIP) scores were used to quantify miRNA contributions to group separation on partial least squares discriminant analysis (PLSDA), and hierarchical clustering was used to visualize expression patterns across individual samples. Fasting and post-prandial miRNA levels were compared across AN and non-AN samples with 2-way analysis of variance (ANOVA). MiRNAs of interest were functionally interrogated in DIANA miRPath software. Relationships between miRNAs and medical/neuropsychiatric characteristics were investigated with Pearson correlation analyses. PLSDA and hierarchical clustering analyses revealed distinct distribution patterns for AN, AX and HC samples. Ten individual miRNAs had significant VIP scores (≥2.0) that were critical for group separation. 5 miRNAs were downregulated in both AN and AX, which may be anxiety related. 5 were upregulated in AN only, suggesting that these changes are related to malnutrition. MiRNAs upregulated in AN identified in DIANA miRPath showed enrichment (FDR < 0.05) for several KEGG pathways including fatty acid biosynthesis (p=2.06E-19, 2 miRNAs), fatty acid metabolism (p=4.00E-07, 8 miRNAs), regulation of pluripotency of stem cells (p=3.83E-06, 14 miRNAs), steroid hormone biosynthesis (p=9.43E-06, 8 miRNAs), biotin metabolism (p=3.66E-05, 2 miRNAs) and GABAergic signaling (p=0.037232, 13 miRNAs) pathways. Three miRNAs demonstrated a dynamic response to food intake by 2-way ANOVA Simultaneous Components Analysis (ASCA) of fasting and post-prandial samples in those with AN and those without AN. All 3 miRNAs tended to be lower in AN during the fasting state and higher in the post-prandial state. Individual miRNA levels were associated with both medical characteristics and neuropsychiatric measures. Salivary miRNA profiles are disrupted in adolescent females with AN, demonstrating potential utility for differentiating adolescent females with AN from peers. These miRNAs are influenced by prandial-status, target genes related to fatty acid metabolism and GABAergic signaling, and are related to neuropsychiatric measures. They yield potential insights into the pathophysiologic milieu underlying AN and may provide an objective measure for tracking AN severity, or treatment response.

Study of Microbiomes in Aseptically Collected Samples of Human Breast Tissue Using Needle Biopsy and the Potential Role of in situ Tissue Microbiomes for Promoting Malignancy.

Mounting evidence suggests that changes in microbiome are linked to development of cancer and its aggressiveness. Microbiome profiles in human breast tissue previously presumed to be sterile, have recently been characterized using high-throughput technologies. Recent findings of microbiome variation between benign and malignant disease provides a rationale for exploring microbiomes associated with cancer during tumor progression. We assessed microbiomes of aseptically collected human breast tissue samples in this study, using needle biopsy from patients with benign and malignant tumors of different histological grading, using 16S rRNA gene amplicon sequencing. This is consistent with previous studies, and our results identified distinct microbiome profiles in breast tissues from women with cancer as compared to women with benign breast disease in Chinese cohorts. The enriched microbial biomarkers in malignant tissue included genus Propionicimonas and families Micrococcaceae, Caulobacteraceae, Rhodobacteraceae, Nocardioidaceae, Methylobacteriaceae, which appeared to be ethno-specific. Further, we compared microbiome profiles in malignant tissues of three different histological grades. The relative abundance of family Bacteroidaceae decreased and that of genus Agrococcus increased with the development of malignancy. KEGG pathways inferred by PICRUSt showed that biotin and glycerophospholipid metabolism had significant differences in all three grades. Glycerophospholipid and ribosome biogenesis increased in grade III tissue as compared to grades I and II. Flavonoid biosynthesis significantly decreased in grade III tissue. The specific correlation of these potential microbial biomarkers and indicated pathways with advanced disease could have broad implications in the diagnosis and staging of breast cancer. Further large-cohort investigation of the breast cancer microbiome and its potential mechanism in breast cancer development are essential.

Multiple Rounds of Artificial Selection Promote Microbe Secondary Domestication-The Case of Cachaça Yeasts.

The study of microbe domestication has witnessed major advances that contribute to a better understanding of the emergence of artificially selected phenotypes and set the foundations of their rational improvement for biotechnology. Several features make Saccharomyces cerevisiae an ideal model for such a study, notably the availability of a catalogue of signatures of artificial selection and the extensive knowledge available on its biological processes. Here, we investigate with population and comparative genomics a set of strains used for cachaça fermentation, a Brazilian beverage based on the fermentation of sugar cane juice. We ask if the selective pressures posed by this fermentation have given rise to a domesticated lineage distinct from the ones already known, like wine, beer, bread, and sake yeasts. Our results show that cachaça yeasts derive from wine yeasts that have undergone an additional round of domestication, which we define as secondary domestication. As a consequence, cachaça strains combine features of wine yeasts, such as the presence of genes relevant for wine fermentation and advantageous gene inactivations, with features of beer yeasts like resistance to the effects of inhibitory compounds present in molasses. For other markers like those related to sulfite resistance and biotin metabolism our analyses revealed distributions more complex than previously reported that support the secondary domestication hypothesis. We propose a multilayered microbe domestication model encompassing not only transitions from wild to primarily domesticated populations, as in the case of wine yeasts, but also secondary domestications like those of cachaça yeasts.

Metabolomics of heat stress response in pig adipose tissue reveals alteration of phospholipid and fatty acid composition during heat stress.

To determine the effect of heat stress (HS) on adipose tissue metabolome, a combination of liquid chromatography-mass spectrometry-based metabolomics profiling approaches was applied to characterize changes of metabolite classes in adipocytes differentiated in culture (in vitro) and mesenteric adipose tissue of pigs exposed to HS (in vivo). Effect of HS on the composition of individual fatty acids in cultured adipocytes, mesenteric adipose tissue, and serum of animals was also investigated using gas chromatography analysis. In vitro, preadipocytes were differentiated either under control (37 °C) or HS (41.5 °C) temperature for 9 d. For the animal experiment, pigs were kept either in control (Con) environment (20 °C) with ad libitum feed intake, HS (35 °C) temperature with ad libitum feed intake (HS), or at 20 °C with pair feeding to the HS pigs. In cultured cells, HS increased triglyceride and decreased monoacylglycerol (P < 0.05) species accumulation compared with control. Phosphatidylinositol and phosphatidylserine were increased by HS, whereas phosphatidylcholine, phosphatidylethanolamine, and phosphatidylglycerol were decreased relative to control (P < 0.05). Heat-stressed adipocytes in culture also had higher concentrations of saturated (SFA) and monounsaturated fatty acids (P < 0.05) relative to control. Pathways of proline and biotin metabolism were elevated (P < 0.05) by HS in adipocytes. The metabolomics signatures in adipocytes cultured under HS indicates that pathways centered around diacylglycerol metabolism are impacted by HS. In adipose tissue from animals in the HS treatment, there was increased (P < 0.05) abundance of 4,8 dimethylnonanoyl carnitine (P < 0.05). Heat-stressed animals also had higher (P < 005) serum linoleic, total polyunsaturated fatty acids, and decreased total SFA than PF (P < 0.05). These results indicate that HS elevates lipogenic pathways while suppressing fatty acid oxidation and demonstrate the usefulness of metabolomics analysis as a tool for determining the impact of HS in pig tissues.

Wrodzony niedobór biotynidazy o późnym początku – opis przypadku

Biotinidase deficiency is a genetically conditioned congenital disorder of biotin metabolism. The disease is caused by mutations in the BTD-3p25 gene, located on the short strand of chromosome 3. The BTD gene conditions proper biotinidase synthesis. So far, approximately 150 mutations of this gene have been identified. The incidence proportion is one case per 61 000 births, and the carrier state – one case per 120 births. Biotin (vit. H, B7) is essential in numerous metabolic processes. The initial phase of the disease can be acute, chronic including exacerbations/remissions, progressive, and the symptoms can appear at any age. The diagnosis of patients with late-onset disease is particularly difficult, since the symptoms suggest disorders of different nature, especially neurologic. The diagnosis is based on the analysis of clinical symptoms and laboratory tests, including biotinidase activity. The supplementation of biotin is the treatment of choice. It leads to rapid resolution of symptoms and can protect against permanent consequences of the disease such as optic atrophy, hearing loss or retarded psychomotor development.

Su1944 - Intestinal Dysbiosis Induces Systemic Dysregulation of Biotin Metabolism, Resulting in Extraintestinal Manifestation

Su1944 - Intestinal Dysbiosis Induces Systemic Dysregulation of Biotin Metabolism, Resulting in Extraintestinal Manifestation

Host biotin is required for liver stage development in malaria parasites

Acetyl-CoA carboxylase (ACC) is a biotin-dependent enzyme that is the target of several classes of herbicides. Malaria parasites contain a plant-like ACC, and this is the only protein predicted to be biotinylated in the parasite. We found that ACC is expressed in the apicoplast organelle in liver- and blood-stage malaria parasites; however, it is activated through biotinylation only in the liver stages. Consistent with this observation, deletion of the biotin ligase responsible for ACC biotinylation does not impede blood-stage growth, but results in late liver-stage developmental defects. Biotin depletion increases the severity of the developmental defects, demonstrating that parasite and host biotin metabolism are required for normal liver-stage progression. This finding may link the development of liver-stage malaria parasites to the nutritional status of the host, as neither the parasite nor the human host can synthesize biotin.

The assessment of metabolite alteration induced by -OH functionalized multi-walled carbon nanotubes in mice using NMR-based metabonomics.

Introduction: There is a fundamental need to characterize multiwalled carbon nanotubes (MWCNTs) toxicity to guarantee their safe application. Functionalized MWCNTs have recently attracted special interest in order to enhance biocompatibility. The aim of the current work was to study the underlying toxicity mechanism of the -OH-functionalized MWCNTs (MWCNTs-OH), using the powerful NMR-based metabonomics technique. Methods: Following intraperitoneal single-injection of mice with 3 doses of MWCNTs-OH and one control, samples were collected at four time points during 22-days for NMR, biochemistry, and histopathology analysis. Metabolome profiling and pathway analysis were implemented by chemometrics tools and metabolome databases. Results: Based on the 1H-NMR data, metabolic perturbation induced by MWCNTs-OH were characterized by altered levels of steroid hormones, including elevated androgens, estrogens, corticosterone, and aldosterone. Moreover, increased L-lysine, aminoadipate, taurine and taurocholic acid and decreased biotin were observed in the high-dose group (1 mg.kg-1 B.W.) compared to the control. The findings also indicated that steroid hormone biosynthesis, lysine biosynthesis, and biotin metabolism are the most affected pathways by MWCNTs-OH. Conclusion: These pathways can reflect perturbation of energy, amino acids, and fat metabolism, as well as oxidative stress. The data obtained by biochemistry, metabonomics, and histopathology were in good agreement, proving that MWCNTs-OH was excreted within 24 h, through the biliary pathway.

Laboratory Evolution of a Biotin-Requiring Saccharomyces cerevisiae Strain for Full Biotin Prototrophy and Identification of Causal Mutations.

Biotin prototrophy is a rare, incompletely understood, and industrially relevant characteristic of Saccharomyces cerevisiae strains. The genome of the haploid laboratory strain CEN.PK113-7D contains a full complement of biotin biosynthesis genes, but its growth in biotin-free synthetic medium is extremely slow (specific growth rate [μ] ≈ 0.01 h-1). Four independent evolution experiments in repeated batch cultures and accelerostats yielded strains whose growth rates (μ ≤ 0.36 h-1) in biotin-free and biotin-supplemented media were similar. Whole-genome resequencing of these evolved strains revealed up to 40-fold amplification of BIO1, which encodes pimeloyl-coenzyme A (CoA) synthetase. The additional copies of BIO1 were found on different chromosomes, and its amplification coincided with substantial chromosomal rearrangements. A key role of this gene amplification was confirmed by overexpression of BIO1 in strain CEN.PK113-7D, which enabled growth in biotin-free medium (μ = 0.15 h-1). Mutations in the membrane transporter genes TPO1 and/or PDR12 were found in several of the evolved strains. Deletion of TPO1 and PDR12 in a BIO1-overexpressing strain increased its specific growth rate to 0.25 h-1 The effects of null mutations in these genes, which have not been previously associated with biotin metabolism, were nonadditive. This study demonstrates that S. cerevisiae strains that carry the basic genetic information for biotin synthesis can be evolved for full biotin prototrophy and identifies new targets for engineering biotin prototrophy into laboratory and industrial strains of this yeast.IMPORTANCE Although biotin (vitamin H) plays essential roles in all organisms, not all organisms can synthesize this vitamin. Many strains of baker's yeast, an important microorganism in industrial biotechnology, contain at least some of the genes required for biotin synthesis. However, most of these strains cannot synthesize biotin at all or do so at rates that are insufficient to sustain fast growth and product formation. Consequently, this expensive vitamin is routinely added to baker's yeast cultures. In this study, laboratory evolution in biotin-free growth medium yielded new strains that grew as fast in the absence of biotin as in its presence. By analyzing the DNA sequences of evolved biotin-independent strains, mutations were identified that contributed to this ability. This work demonstrates full biotin independence of an industrially relevant yeast and identifies mutations whose introduction into other yeast strains may reduce or eliminate their biotin requirements.

Profiling of the perturbed metabolomic state of mouse spleen during acute and chronic toxoplasmosis

BackgroundToxoplasma gondii, a common opportunistic protozoan, is a leading cause of illness and mortality among immunosuppressed individuals and during congenital infections. Current therapeutic strategies for toxoplasmosis are not fully effective at curtailing disease progression in these cases. Given the parasite ability to influence host immunity and metabolism, understanding of the metabolic alterations in the host’s immune organs during T. gondii infection may enhance the understanding of the molecular mechanisms that define the pathophysiology of T. gondii infection.MethodsWe investigated the global metabolic changes in the spleen of BALB/c mice at early and late stage of infection with T. gondii using LC-MS/MS-based metabolomics. Multivariate data analysis methods, principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA), were used to identify metabolites that are influenced by T. gondii infection.ResultsMultivariate analyses clearly separated the metabolites of spleen of infected and control mice. A total of 132 differential metabolites were identified, 23 metabolites from acutely infected versus control mice and 109 metabolites from chronically infected versus control mice. Lipids, hormones, lactones, acids, peptides, antibiotics, alkaloids and natural toxins were the most influenced chemical groups. There were 12 shared differential metabolites between acutely infected versus control mice and chronically infected versus control mice, of which 4,4-Dimethyl-5alpha-cholesta-8,14,24-trien-3beta-ol was significantly upregulated and ubiquinone-8 was significantly downregulated. Major perturbed metabolic pathways included primary bile acid biosynthesis, steroid hormone biosynthesis, biotin metabolism, and steroid biosynthesis, with arachidonic acid metabolism being the most significantly impacted pathway. These metabolic changes suggest a multifactorial nature of the immunometabolic responses of mouse spleen to T. gondii infection.ConclusionsThis study demonstrated that T. gondii infection can cause significant metabolomic alterations in the spleen of infected mice. These findings provide new insights into the molecular mechanisms that underpin the pathogenesis of T. gondii infection.

Helium Influences Caveolae Numbers in Left Ventricular Endothelial Cells and Alters Metabolic Profile in Mice

BackgroundMyocardial ischemia and reperfusion (I/R) injury is a major cause of morbidity and mortality. IR injury leads to calcium overload, increased oxidative stress, mitochondrial dysfunction and ultimately apoptosis. Helium, an inert gas, causes cardioprotection potentially through secretion of cellular factors into serum. This study aimed to elucidate the protective potential of helium conditioned serum, the metabolite content of serum, and the impact of helium on endothelial cell ultrastructure. We hypothesized that helium induces the release of circulating factors to mediate conditioning and impacts endothelial cell ultrastructure.Materials and methodsMice were exposed to 70% helium/30% oxygen or 30% oxygen in air. Serum was harvested at 30 min, 4 hrs and 24 hrs after gas exposure (n=7/group). In addition, mice (n=4/group) were prepared and fixed for transmission electron microscopy. High magnification images (11000×) of left ventricular tissue were analyzed for the amount of caveolae in endothelial cells and myocytes. Serum from exposed mice was analyzed for metabolites of primary metabolism and complex lipids by mass spectrometry. Metabolites were categorized by physiologic pathways and multivariate analysis was used to determine interaction between helium and recover time.ResultsEndothelial cell caveolae number was increased at 30 min and 24 hrs post exposure in the helium group by 39% (p &lt; 0.01, C: 3.5 ± 0.2, n=83 images; He: 4.8 ± 0.3 caveolae/mm, n=67 as mean ± SEM) and 18% (p &lt; 0.05, C: 4.3 ± 0.3, n=72; He: 5.3 ± 0.3 caveolae/mm, n=61), respectively. No differences were observed in myocyte caveolae formation. Interaction of time and drug showed a trend for oxidative phosphorylation (p= 0.097) and galactose metabolism pathway (p= 0.0798). An overall drug effect between the different time points was observed for biotin metabolism (p &lt; 0.05). The metabolites of the two pathways, valine/leucine/isoleucine and pantothenate/CoA biosynthesis showed a trend towards a drug effect (p=0.053; p=0.057 respectively). Three pathways were significantly changed in the 4 hrs group and in the 24 hrs group biosynthesis of unsaturated fatty acids was influenced. In addition three cardioprotective ceramides were significantly upregulated by helium (p &lt; 0.05).ConclusionHelium exposure altered endothelial cell ultrastructure by inducing the formation of caveolae and induced secretion of factors resulting in different metabolic profiles of primary metabolism and complex lipids. Such changes in cell ultrastructure and metabolite secretion may be key to the conditioning effects induced by helium.

Starter feeding altered ruminal epithelial bacterial communities and some key immune-related genes' expression before weaning in lambs.

To characterize changes in ruminal epithelial bacterial communities and immune-related gene expression during concentrate starter feeding before weaning in lambs, 6 pairs of 10-d-old Hu lamb twins were selected: 1 kid received milk (M, = 6), and the other received milk plus starter (M+S, = 6). All lambs received hay and water ad libitum and were slaughtered at 56-d-old. Their rumen fluid was collected to determine ruminal pH and VFA levels; rumen epithelia were collected to characterize their bacterial communities using Illumina MiSeq sequencing and to determine mRNA expression of immune-related genes using quantitative real-time PCR (qRT-PCR). Results showed that starter feeding caused a decreased ruminal pH ( = 0.004) and increased concentrations of acetate, propionate, butyrate, and total VFA ( < 0.001). Principal coordinate analysis and analysis of molecular variance revealed that starter feeding affected ruminal epithelial bacterial communities in the lambs ( = 0.001), with higher relative abundance of dominant taxa , unclassified BS11 gut group, , unclassified Synergistaceae, , , , , and ( < 0.05) but lesser relative abundance of , unclassified Bacteroidales, unclassified Candidate, unclassified RF9, and ( < 0.05). Additionally, a phylogenetic investigation of communities by reconstruction of unobserved states analysis indicated that starter feeding markedly increased relative abundance values of dominant ruminal epithelial bacterial-inferred genes related to other ion-coupled transporters, pentose and glucuronate interconversions, glycosyltransferases, other glycan degradation, AA metabolism, sphingolipid metabolism, biotin metabolism, glycosphingolipid biosynthesis-globo series, and lysosome ( < 0.05) but decreased relative abundance values of genes related to carbon fixation pathways in prokaryotes and energy metabolism ( < 0.05) in the lambs. The qRT-PCR results showed that starter feeding decreased the relative mRNA expression of IL-6 ( = 0.003), IL-10 ( = 0.013), and interferon γ ( = 0.003). Collectively, this study showed that starter feeding could alter ruminal epithelial bacterial communities and some key immune-related genes' expression in preweaned lambs. All these responses of ruminal epithelial bacteria and the immune system would be beneficial for starter-fed lambs to be weaned.

A glimpse into the genetic basis of symbiosis between Hydrogenophaga and their helper strains in the biodegradation of 4-aminobenzenesulfonate.

We report the whole genome sequences of Hydrogenophaga intermedia S1 and Agrobacterium radiobacter S2, the first reported bacterial co-culture capable of degrading 4-aminobenzenesulfonate (4-ABS), a recalcitrant industrial waste product. To gain insights into the genetic basis for the syntrophic interaction between this symbiotic pair and also another recently reported Hydrogenophaga associated co-culture, Hydrogenophaga sp. PBC and Ralstonia sp. PBA, we performed detailed genetic analysis of these four strains focusing on the metabolic pathways associated with biotin, para-aminobenzoic acid (pABA), and protocatechuate metabolism. Both assembled Hydrogenophaga draft genomes are missing a majority of the genetic components associated in the biosynthetic pathway of pABA and biotin. Interestingly, a fused pABA synthase was found in R. sp PBA but not in A. radiobacter S2. Furthermore, using whole genome data, the taxonomic classification of R. sp. PBA and A. radiobacter S2 (both previously inferred from 16S rRNA gene) was re-investigated, providing new evidence to propose for their re-classification at the genus and species level, respectively

West Syndrome Secondary to Biotinidase Deficiency about a Case

Biotinidase deficiency is an abnormality of biotin metabolism which is manifested by neurological, cutaneous, ophthalmological and auditory signs. It has been described as a cause of West syndrome, but there are few observations that report an association between these latter two. We report the observation of an 18-month old infant born from a first-degree consanguineous marriage, followed since the age of 2 months and half for West syndrome associated with alopecia, also an eczema and deafness in whom the etiological investigation was in favor of a biotinidase deficiency. Thus treatment with biotin resulted in a marked clinical improvement.

Clinical, Biochemical and Genetic Analysis of Biotinidase Deficiency in Iranian Population.

Biotinidase deficiency (BTD) is an autosomal recessive disorder of biotin metabolism. Biotin is a coenzyme that enhances the action of the four enzymes that play an important role in carbohydrates, amino acid, and fatty acid metabolism. Defects in these pathways cause severe metabolic disorder in the body. In general, biotinidase deficiency can be classified into two levels: partial and profound. The incidence of BTD is 1:40,000 to 1:60,000 births in the world, even though no convincing statistical data on the prevalence of this disorder exist in Iran. In this study, we aimed to set up a test for determining biotinidase activity among the Iranian population and report BTD mutations. The quantitative method for the determination of biotinidase activity was set up in the National Biochemistry Reference Laboratory (NBRL) of Pasteur Institute of Iran in Tehran. To detect mutations in BTD, polymerase chain reaction (PCR) was performed followed by DNA sequencing. The biotinidase activity range values were 3.81 - 8.25 nmol/min/mL. We identified 8 BTD patients out of 47 cases with neurologic signs. We detected two mutations, c.98-104del7ins3 and p.Arg79Cys, in 5 patients with profound BTD, and one p.Asp444His mutation in 3 patients with partial BTD. Infants suffering from BTD seem healthy during their first months of life. At present, the screening program for metabolic disorders such as BTD is in progress. The patients that are BTD deficient benefit from the availability of the tests, and consequently receive the Biotin supplements before being clinically affected.

Holocarboxylase synthetase deficiency pre and post newborn screening

Holocarboxylase synthetase deficiency is an autosomal recessive disorder of biotin metabolism resulting in multiple carboxylase deficiency. The typical presentation described in the medical literature is of neonatal onset within hours to weeks of birth with emesis, hypotonia, lethargy, seizures, metabolic ketolactic acidosis, hyperammonemia, developmental delay, skin rash and alopecia. The condition is screened for by newborn screening (NBS) tandem mass spectroscopy by elevated hydroxypentanoylcarnitine on dried blood spots. Urine organic acid profile may demonstrate elevated lactic, 3-OH isovaleric, 3-OH propionic, 3-MCC, methylcitric acids, and tiglylglycine consistent with loss of function of the above carboxylases. Here we describe a cohort of patients, 2 diagnosed pre-NBS and 3 post-NBS with broad differences in initial presentation and phenotype. In addition, prior to the advent of NBS, there are isolated reports of late-onset holocarboxylase synthetase deficiency in the medical literature, which describe patients diagnosed between 1 and 8years of life, however to our knowledge there are no reports of late-onset HCLS being missed by NBS. Also we report two cases, each with novel pathogenic variants HCLS, diagnosed at age 3years and 21months respectively. The first patient had a normal newborn screen whilst the second had an abnormal newborn screen but was misdiagnosed as 3-methylcrotonylcarboxylase (3-MCC) deficiency and subsequently lost to follow-up until they presented again with severe metabolic acidosis.

Transcriptome and Gene Ontology (GO) Enrichment Analysis Reveals Genes Involved in Biotin Metabolism That Affect L-Lysine Production in Corynebacterium glutamicum.

Corynebacterium glutamicum is widely used for amino acid production. In the present study, 543 genes showed a significant change in their mRNA expression levels in l-lysine-producing C. glutamicum ATCC21300 than that in the wild-type C. glutamicum ATCC13032. Among these 543 differentially expressed genes (DEGs), 28 genes were up- or downregulated. In addition, 454 DEGs were functionally enriched and categorized based on BLAST sequence homologies and gene ontology (GO) annotations using the Blast2GO software. Interestingly, NCgl0071 (bioB, encoding biotin synthase) was expressed at levels ~20-fold higher in the l-lysine-producing ATCC21300 strain than that in the wild-type ATCC13032 strain. Five other genes involved in biotin metabolism or transport—NCgl2515 (bioA, encoding adenosylmethionine-8-amino-7-oxononanoate aminotransferase), NCgl2516 (bioD, encoding dithiobiotin synthetase), NCgl1883, NCgl1884, and NCgl1885—were also expressed at significantly higher levels in the l-lysine-producing ATCC21300 strain than that in the wild-type ATCC13032 strain, which we determined using both next-generation RNA sequencing and quantitative real-time PCR analysis. When we disrupted the bioB gene in C. glutamicum ATCC21300, l-lysine production decreased by approximately 76%, and the three genes involved in biotin transport (NCgl1883, NCgl1884, and NCgl1885) were significantly downregulated. These results will be helpful to improve our understanding of C. glutamicum for industrial amino acid production.

Serum Biotin Levels in Women Complaining of Hair Loss.

Biotin is a coenzyme for carboxylase enzymes that assist various metabolic reactions involved in fatty acid synthesis, branched-chain amino acid catabolism, and gluconeogenesis important for maintenance of healthy skin and hair. Due to its availability, affordability, and effective marketing for this purpose, biotin is a popular nutritional supplement for treatment of hair loss. However, there are little data on the frequency of biotin deficiency in patients complaining of hair loss and on the value of oral biotin for treatment of hair loss that is not due to an inborn error of biotin metabolism or deficiency. The aim of this study was to determine the frequency and significance of biotin deficiency in women complaining of hair loss. Biotin deficiency was found in 38% of women complaining of hair loss. Of those showing diffuse telogen effluvium in trichograms (24%), 35% had evidence of associated seborrheic-like dermatitis. About 11% of patients with biotin deficiency had a positive personal history for risk factors for biotin deficiency. The custom of treating women complaining of hair loss in an indiscriminate manner with oral biotin supplementation is to be rejected, unless biotin deficiency and its significance for the complaint of hair loss in an individual has been demonstrated on the basis of a careful patient history, clinical examination, determination of serum biotin levels, and exclusion of alternative factors responsible for hair loss.

Outcomes of oral biotin treatment in patients with biotinidase deficiency — Twenty years follow-up

IntroductionBiotinidase deficiency (BTD) is an inborn error of biotin metabolism inherited as an autosomal recessive trait. Due to the, biotinidase deficiency, biotin is not recycled. Individuals with BTD usually exhibit neurological and cutaneous abnormalities unless treated with biotin. Supplementation with biotin may either ameliorate or if early introduced even prevent symptoms when introduced presymptomatically. Patients and methodsSince 1991, 22 Polish patients from 19 families have been diagnosed with BTD. In 16 children the diagnosis had been suspected on the basis of clinical signs: skin lesions, hyperventilation, seizures, spasticity, and laboratory investigation (elevated lactate and metabolites on urine organic acids profile).The defect was enzymatically (serum biotinidase activity measurement) and genetically (tested for mutations in the BTD gene) confirmed afterwards. All patients were treated with biotin. Urine organic acids analysis (GC/MS) for 3-hydroxizovaleric acid was used for patients' monitoring. Neurological, audiological and ophthalmological evaluation has been conducted once a year. ResultsIn 5 symptomatic patients a progressive optic nerve atrophy had already been noted at the time of treatment initiation. In these patients sensorineural hearing loss has also been diagnosed despite biotin supplementation. Asymptomatic patients treated with biotin supplementation presented no signs or symptoms of BTD. Supplementation with biotin slows the progression of BTD in symptomatic patients, but does not reverse nerve atrophy. Nonetheless, introduction of the treatment with biotin during presymptomatic stage of the disease prevents the onset of symptoms including optic atrophy and hearing loss. Homozygosity for the p.Leu215Phe mutation in BTD gene seems to be frequent in patients from the North-Eastern region of Poland and is connected with the hearing loss. ConclusionSince the prognosis for individuals diagnosed with BTD is good, provided they are treated before symptoms occur, it is justified to add this metabolic disorder to the panel of conditions screened under the national newborn screening programme in Poland.

A microsphere-based assay for mutation analysis of the biotinidase gene using dried blood spots

Biotinidase deficiency is an autosomal recessive syndrome caused by defects in the biotinidase gene, the product of which affects biotin metabolism. Newborn screening (NBS) for biotinidase deficiency can identify affected infants prior to onset of symptoms; biotin supplementation can resolve or prevent the clinical features. In NBS, dry blood spots (DBS) are usually tested for biotinidase enzyme activity by colorimetric analysis. By taking advantage of the multiplexing capabilities of the Luminex platform, we have developed a microsphere-based array genotyping method for the simultaneous detection of six disease causing mutations in the biotinidase gene, thereby permitting a second tier of molecular analysis. Genomic DNA was extracted from 3.2 mm DBS. Biotinidase gene sequences, containing the mutations of interest, were amplified by multiplexed polymerase chain reaction, followed by multiplexed allele-specific primer extension using universally tagged genotyping primers. The products were then hybridized to anti-tag carrying xTAG microspheres and detected on the Luminex platform. Genotypes were verified by sequencing. Genotyping results of 22 known biotinidase deficient samples by our xTAG biotinidase assay was in concordance with the results obtained from DNA sequencing, for all 6 mutations used in our panel. These results indicate that genotyping by an xTAG microsphere-based array is accurate, flexible, and can be adapted for high-throughput. Since NBS for biotinidase deficiency is by enzymatic assay, less than optimal quality of the DBS itself can compromise enzyme activity, while the DNA from these samples mostly remains unaffected. This assay warrants evaluation as a viable complement to the biotinidase semi-quantitative colorimetric assay.