Literature Watch

ProtozoaDB 2.0: A Trypanosoma Brucei Case Study.

Systems Biology - Fri, 2017-07-21 09:08
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ProtozoaDB 2.0: A Trypanosoma Brucei Case Study.

Pathogens. 2017 Jul 20;6(3):

Authors: Jardim R, Tschoeke D, Da Vila AMR

Abstract
Over the last decade new species of Protozoa have been sequenced and deposited in GenBank. Analyzing large amounts of genomic data, especially using Next Generation Sequencing (NGS), is not a trivial task, considering that researchers used to deal or focus their studies on few genes or gene families or even small genomes. To facilitate the information extraction process from genomic data, we developed a database system called ProtozoaDB that included five genomes of Protozoa in its first version. In the present study, we present a new version of ProtozoaDB called ProtozoaDB 2.0, now with the genomes of 22 pathogenic Protozoa. The system has been fully remodeled to allow for new tools and a more expanded view of data, and now includes a number of analyses such as: (i) similarities with other databases (model organisms, the Conserved Domains Database, and the Protein Data Bank); (ii) visualization of KEGG metabolic pathways; (iii) the protein structure from PDB; (iv) homology inferences; (v) the search for related publications in PubMed; (vi) superfamily classification; and (vii) phenotype inferences based on comparisons with model organisms. ProtozoaDB 2.0 supports RESTful Web Services to make data access easier. Those services were written in Ruby language using Ruby on Rails (RoR). This new version also allows a more detailed analysis of the object of study, as well as expanding the number of genomes and proteomes available to the scientific community. In our case study, a group of prenyltransferase proteinsalready described in the literature was found to be a good drug target for Trypanosomatids.

PMID: 28726736 [PubMed]

Categories: Literature Watch

Genome sequence of the type strain CLIB 1764(T) (= CBS 14374(T)) of the yeast species Kazachstania saulgeensis isolated from French organic sourdough.

Systems Biology - Fri, 2017-07-21 09:08
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Genome sequence of the type strain CLIB 1764(T) (= CBS 14374(T)) of the yeast species Kazachstania saulgeensis isolated from French organic sourdough.

Genom Data. 2017 Sep;13:41-43

Authors: Sarilar V, Sterck L, Matsumoto S, Jacques N, Neuvéglise C, Tinsley CR, Sicard D, Casaregola S

Abstract
Kazachstania saulgeensis is a recently described species isolated from French organic sourdough. Here, we report the high quality genome sequence of a monosporic segregant of the type strain of this species, CLIB 1764(T) (= CBS 14374(T)). The genome has a total length of 12.9 Mb and contains 5326 putative protein-coding genes, excluding pseudogenes and transposons. The nucleotide sequences were deposited into the European Nucleotide Archive under the genome assembly accession numbers FXLY01000001-FXLY01000017.

PMID: 28725555 [PubMed]

Categories: Literature Watch

Logarithmic sensing in Bacillus subtilis aerotaxis.

Systems Biology - Fri, 2017-07-21 09:08
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Logarithmic sensing in Bacillus subtilis aerotaxis.

NPJ Syst Biol Appl. 2017;3:16036

Authors: Menolascina F, Rusconi R, Fernandez VI, Smriga S, Aminzare Z, Sontag ED, Stocker R

Abstract
Aerotaxis, the directed migration along oxygen gradients, allows many microorganisms to locate favorable oxygen concentrations. Despite oxygen's fundamental role for life, even key aspects of aerotaxis remain poorly understood. In Bacillus subtilis, for example, there is conflicting evidence of whether migration occurs to the maximal oxygen concentration available or to an optimal intermediate one, and how aerotaxis can be maintained over a broad range of conditions. Using precisely controlled oxygen gradients in a microfluidic device, spanning the full spectrum of conditions from quasi-anoxic to oxic (60 n mol/l-1 m mol/l), we resolved B. subtilis' 'oxygen preference conundrum' by demonstrating consistent migration towards maximum oxygen concentrations ('monotonic aerotaxis'). Surprisingly, the strength of aerotaxis was largely unchanged over three decades in oxygen concentration (131 n mol/l-196 μ mol/l). We discovered that in this range B. subtilis responds to the logarithm of the oxygen concentration gradient, a rescaling strategy called 'log-sensing' that affords organisms high sensitivity over a wide range of conditions. In these experiments, high-throughput single-cell imaging yielded the best signal-to-noise ratio of any microbial taxis study to date, enabling the robust identification of the first mathematical model for aerotaxis among a broad class of alternative models. The model passed the stringent test of predicting the transient aerotactic response despite being developed on steady-state data, and quantitatively captures both monotonic aerotaxis and log-sensing. Taken together, these results shed new light on the oxygen-seeking capabilities of B. subtilis and provide a blueprint for the quantitative investigation of the many other forms of microbial taxis.

PMID: 28725484 [PubMed]

Categories: Literature Watch

Integrating highly quantitative proteomics and genome-scale metabolic modeling to study pH adaptation in the human pathogen Enterococcus faecalis.

Systems Biology - Fri, 2017-07-21 09:08
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Integrating highly quantitative proteomics and genome-scale metabolic modeling to study pH adaptation in the human pathogen Enterococcus faecalis.

NPJ Syst Biol Appl. 2016;2:16017

Authors: Großeholz R, Koh CC, Veith N, Fiedler T, Strauss M, Olivier B, Collins BC, Schubert OT, Bergmann F, Kreikemeyer B, Aebersold R, Kummer U

Abstract
Genome-scale metabolic models represent the entirety of metabolic reactions of an organism based on the annotation of the respective genome. These models commonly allow all reactions to proceed concurrently, disregarding the fact that at no point all proteins will be present in a cell. The metabolic reaction space can be constrained to a more physiological state using experimentally obtained information on enzyme abundances. However, high-quality, genome-wide protein measurements have been challenging and typically transcript abundances have been used as a surrogate for protein measurements. With recent developments in mass spectrometry-based proteomics, exemplified by SWATH-MS, the acquisition of highly quantitative proteome-wide data at reasonable throughput has come within reach. Here we present methodology to integrate such proteome-wide data into genome-scale models. We applied this methodology to study cellular changes in Enterococcus faecalis during adaptation to low pH. Our results indicate reduced proton production in the central metabolism and decreased membrane permeability for protons due to different membrane composition. We conclude that proteomic data constrain genome-scale models to a physiological state and, in return, genome-scale models are useful tools to contextualize proteomic data.

PMID: 28725473 [PubMed]

Categories: Literature Watch

Lack of Associations between Female Hormone Levels and Visuospatial Working Memory, Divided Attention and Cognitive Bias across Two Consecutive Menstrual Cycles.

Systems Biology - Fri, 2017-07-21 09:08
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Lack of Associations between Female Hormone Levels and Visuospatial Working Memory, Divided Attention and Cognitive Bias across Two Consecutive Menstrual Cycles.

Front Behav Neurosci. 2017;11:120

Authors: Leeners B, Kruger THC, Geraedts K, Tronci E, Mancini T, Ille F, Egli M, Röblitz S, Saleh L, Spanaus K, Schippert C, Zhang Y, Hengartner MP

Abstract
Background: Interpretation of observational studies on associations between prefrontal cognitive functioning and hormone levels across the female menstrual cycle is complicated due to small sample sizes and poor replicability. Methods: This observational multisite study comprised data of n = 88 menstruating women from Hannover, Germany, and Zurich, Switzerland, assessed during a first cycle and n = 68 re-assessed during a second cycle to rule out practice effects and false-positive chance findings. We assessed visuospatial working memory, attention, cognitive bias and hormone levels at four consecutive time-points across both cycles. In addition to inter-individual differences we examined intra-individual change over time (i.e., within-subject effects). Results: Estrogen, progesterone and testosterone did not relate to inter-individual differences in cognitive functioning. There was a significant negative association between intra-individual change in progesterone and change in working memory from pre-ovulatory to mid-luteal phase during the first cycle, but that association did not replicate in the second cycle. Intra-individual change in testosterone related negatively to change in cognitive bias from menstrual to pre-ovulatory as well as from pre-ovulatory to mid-luteal phase in the first cycle, but these associations did not replicate in the second cycle. Conclusions: There is no consistent association between women's hormone levels, in particular estrogen and progesterone, and attention, working memory and cognitive bias. That is, anecdotal findings observed during the first cycle did not replicate in the second cycle, suggesting that these are false-positives attributable to random variation and systematic biases such as practice effects. Due to methodological limitations, positive findings in the published literature must be interpreted with reservation.

PMID: 28725187 [PubMed]

Categories: Literature Watch

Selective Inhibition of Host Cell Signaling for Rotavirus Antivirals: PI3K/Akt/mTOR-Mediated Rotavirus Pathogenesis.

Drug Repositioning - Fri, 2017-07-21 06:07
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Selective Inhibition of Host Cell Signaling for Rotavirus Antivirals: PI3K/Akt/mTOR-Mediated Rotavirus Pathogenesis.

Virulence. 2017 Jul 19;:0

Authors: Kindrachuk J

PMID: 28723236 [PubMed - as supplied by publisher]

Categories: Literature Watch

Beta-Ketothiolase Deficiency Presenting with Metabolic Stroke After a Normal Newborn Screen in Two Individuals.

Orphan or Rare Diseases - Fri, 2017-07-21 06:07
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Beta-Ketothiolase Deficiency Presenting with Metabolic Stroke After a Normal Newborn Screen in Two Individuals.

JIMD Rep. 2017 Jul 20;:

Authors: Wojcik MH, Wierenga KJ, Rodan LH, Sahai I, Ferdinandusse S, Genetti CA, Towne MC, Peake RWA, James PM, Beggs AH, Brownstein CA, Berry GT, Agrawal PB

Abstract
Beta-ketothiolase (mitochondrial acetoacetyl-CoA thiolase) deficiency is a genetic disorder characterized by impaired isoleucine catabolism and ketone body utilization that predisposes to episodic ketoacidosis. It results from biallelic pathogenic variants in the ACAT1 gene, encoding mitochondrial beta-ketothiolase. We report two cases of beta-ketothiolase deficiency presenting with acute ketoacidosis and "metabolic stroke." The first patient presented at 28 months of age with metabolic acidosis and pallidal stroke in the setting of a febrile gastrointestinal illness. Although 2-methyl-3-hydroxybutyric acid and trace quantities of tiglylglycine were present in urine, a diagnosis of glutaric acidemia type I was initially suspected due to the presence of glutaric and 3-hydroxyglutaric acids. A diagnosis of beta-ketothiolase deficiency was ultimately made through whole exome sequencing which revealed compound heterozygous variants in ACAT1. Fibroblast studies for beta-ketothiolase enzyme activity were confirmatory. The second patient presented at 6 months of age with ketoacidosis, and was found to have elevations of urinary 2-methyl-3-hydroxybutyric acid, 2-methylacetoacetic acid, and tiglylglycine. Sequencing of ACAT1 demonstrated compound heterozygous presumed causative variants. The patient exhibited choreoathethosis 2 months after the acute metabolic decompensation. These cases highlight that, similar to a number of other organic acidemias and mitochondrial disorders, beta-ketothiolase deficiency can present with metabolic stroke. They also illustrate the variability in clinical presentation, imaging, and biochemical evaluation that make screening for and diagnosis of this rare disorder challenging, and further demonstrate the value of whole exome sequencing in the diagnosis of metabolic disorders.

PMID: 28726122 [PubMed - as supplied by publisher]

Categories: Literature Watch

Less is more - time to concentrate experience to improve outcomes?

Orphan or Rare Diseases - Fri, 2017-07-21 06:07
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Less is more - time to concentrate experience to improve outcomes?

Colorectal Dis. 2016 Sep;18(9):837-8

Authors: Myrelid P

PMID: 27586702 [PubMed - indexed for MEDLINE]

Categories: Literature Watch

Genetic Variants of Cytochrome CYP2D6 in Two Mixed Chilean Populations.

Pharmacogenomics - Fri, 2017-07-21 06:07

Genetic Variants of Cytochrome CYP2D6 in Two Mixed Chilean Populations.

Hum Hered. 2017 Jul 21;82(1-2):16-20

Authors: Acuña M, Pinto E, Olivares P, Ríos C

Abstract
OBJECTIVES: It is known that the interindividual and interethnic variability of the genetic polymorphisms of CYP2D6 plays an important role in the presentation of adverse drug reactions and concerning lack of therapeutic effects in humans. However, there are few data available from mixed populations of Latin America, including the Chilean. The aim of this study was therefore to estimate the frequencies of CYP2D6 variants in two samples of hospitals from the northern (Hospital San José, HSJ) and eastern (Clínica Las Condes, CLC) parts of Santiago, Chile, with different degrees of Amerindian admixture (HSJ: 34.5%; CLC: 15.9%).
METHODS: We used polymerase chain reaction followed by restriction endonuclease digestion (PCR-RFLP) to genotype 7 CYP2D6 alleles in 250 healthy unrelated individuals of Chilean Mestizo background. The detection of allele CYP2D6*5 and the duplication of this gene was performed by long-PCR.
RESULTS: The degrees of Amerindian admixture are reflected in the observed frequencies of the CYP2D6*1 (HSJ: 58.26%; CLC: 41.06%), CYP2D6*2 (HSJ: 28.10%; CLC: 40.65%), and CYP2D6*4 (HSJ: 8.26%; CLC: 12.60%) alleles; the frequencies of CYP2D6*1 (p = 0.0002) and CYP2D6*2 (p = 0.0036) are significantly different between the samples. Four individuals (CLC: 0.41%; HSJ: 1.24%) could not be assigned to a genotype. We identified 3.25% of the genotypes which predict a poor metabolizer phenotype in CLC and 1.65% in HSJ.
CONCLUSION: Our data indicate ethnic group-dependent genetic differences in the vulnerability to treatment with the large variety of drugs metabolized by the enzyme CYP2D6.

PMID: 28728153 [PubMed - as supplied by publisher]

Categories: Literature Watch

Replication confirms the association of loci in FOXE1, PDE8B, CAPZB and PDE10A with thyroid traits: a Genetics of Diabetes Audit and Research Tayside study.

Pharmacogenomics - Fri, 2017-07-21 06:07

Replication confirms the association of loci in FOXE1, PDE8B, CAPZB and PDE10A with thyroid traits: a Genetics of Diabetes Audit and Research Tayside study.

Pharmacogenet Genomics. 2017 Jul 19;:

Authors: Soto-Pedre E, Siddiqui MK, Doney AS, Palmer CNA, Pearson ER, Leese GP

Abstract
OBJECTIVE: Replication of associations in genome-wide association studies is desirable to ensure that such signals are potentially clinically meaningful. This study aimed to replicate associations of selected single-nucleotide polymorphisms (SNPs) with hypothyroidism and serum thyroid-stimulating hormone (TSH) using electronic medical records (EMRs).
PATIENTS AND METHODS: A cross-sectional study was carried out among patients of European Caucasian ethnicity from the Genetics of Diabetes Audit and Research Tayside recruited in Tayside (Scotland, UK). EMRs (biochemistry, prescribing, hospital admissions and demographics) were used to ascertain patients with hypothyroidism and their controls as well as average serum TSH concentration, and linked to genetic biobank data. Genetic tests of association were performed using logistic and linear regression models.
RESULTS: We analysed 1703 cases of hypothyroidism and 9457 controls. All four SNPs located on chromosome 9 at FOXE1 were associated with hypothyroidism with similar effect estimates (odds ratio=0.75-0.76, P<5e-08). Also, loci on chromosomes 1 (PTPN22), six (HLA-E/HLA-C) and 12 (SH2B3) were replicated. For serum TSH, we confirmed 12 SNPs previously reported at PDE8B, CAPZB, PDE10A, LOC105371356, NR3C2, VEGFA, IGFBP5, INSR, PRDM11, NFIA, ITPK1 and ABO. Overall, these SNPs accounted for 6.8% of the serum TSH variation (P<1e-04).
CONCLUSION: EMRs linked to genomic data in large populations enable validation of genome-wide association studies discoveries without additional genotyping costs. Our replication confirmed at genome-wide significance the association of loci at FOXE1 with hypothyroidism, and PDE8B, CAPZB and PDE10A with serum TSH. A total of 12 SNPs seemed to explain nearly 7% of the serum TSH variation.

PMID: 28727628 [PubMed - as supplied by publisher]

Categories: Literature Watch

A primer on exocrine pancreatic insufficiency, fat malabsorption, and fatty acid abnormalities.

Cystic Fibrosis - Fri, 2017-07-21 06:07

A primer on exocrine pancreatic insufficiency, fat malabsorption, and fatty acid abnormalities.

Am J Manag Care. 2017 Jul;23(12 Suppl):S203-S209

Authors: Alkaade S, Vareedayah AA

Abstract
Exocrine pancreatic insufficiency (EPI) is characterized by a deficiency of exocrine pancreatic enzymes, resulting in deficits in digestion of all macronutrients, with deficiencies in digestion of fats being the most clinically relevant. The leading cause of EPI is chronic pancreatitis. However, many other causes and conditions may be implicated, including cystic fibrosis, pancreatic duct obstruction, gastric and pancreatic surgery, diabetes mellitus and other conditions. Physical and biochemical causes of EPI include decreased production and secretion of lipase, increased lipase destruction, pancreatic duct obstruction, decreased lipase stimulation and degradation, as well as gastrointestinal motility disorders. EPI is largely diagnosed clinically, and is often identified by symptoms such as steatorrhea, weight loss, abdominal discomfort, and abdominal bloating. Lifestyle modifications (eg, smoking cessation, limiting or avoiding alcoholic drinks, and reducing dietary fat intake) and exogenous pancreatic enzyme supplements are commonly used to help restore normal digestion and absorption of dietary nutrients in patients with EPI.

PMID: 28727474 [PubMed - in process]

Categories: Literature Watch

Telephone monitoring and home visits significantly improved the quality of life, treatment adherence and lung function in children with cystic fibrosis.

Cystic Fibrosis - Fri, 2017-07-21 06:07

Telephone monitoring and home visits significantly improved the quality of life, treatment adherence and lung function in children with cystic fibrosis.

Acta Paediatr. 2017 Jul 20;:

Authors: Chrysochoou EA, Hatziagorou E, Kirvassilis F, Tsanakas J

Abstract
Cystic Fibrosis (CF) is a chronic and systemic disease with a progressive course. As survival rates continue to improve, there is a growing demand for new therapeutic options that improve treatment adherence, disease management and quality of life (QoL) (1). The aim of this study was to evaluate the safety and effectiveness of a home care programme for children with CF and to assess the value of regular telephone contact with the CF team based at Hippokration Hospital, Thessaloniki, Greece. This article is protected by copyright. All rights reserved.

PMID: 28727186 [PubMed - as supplied by publisher]

Categories: Literature Watch

Respiratory Tract Infections and the Role of Biologically Active Polysaccharides in Their Management and Prevention.

Cystic Fibrosis - Fri, 2017-07-21 06:07

Respiratory Tract Infections and the Role of Biologically Active Polysaccharides in Their Management and Prevention.

Nutrients. 2017 Jul 20;9(7):

Authors: Jesenak M, Urbancikova I, Banovcin P

Abstract
Respiratory tract infections (RTIs) are the most common form of infections in every age category. Recurrent respiratory tract infections (RRTIs), a specific form of RTIs, represent a typical and common problem associated with early childhood, causing high indirect and direct costs on the healthcare system. They are usually the consequence of immature immunity in children and high exposure to various respiratory pathogens. Their rational management should aim at excluding other severe chronic diseases associated with increased morbidity (e.g., primary immunodeficiency syndromes, cystic fibrosis, and ciliary dyskinesia) and at supporting maturity of the mucosal immune system. However, RRTIs can also be observed in adults (e.g., during exhausting and stressful periods, chronic inflammatory diseases, secondary immunodeficiencies, or in elite athletes) and require greater attention. Biologically active polysaccharides (e.g., β-glucans) are one of the most studied natural immunomodulators with a pluripotent mode of action and biological activity. According to many studies, they possess immunomodulatory, anti-inflammatory, and anti-infectious activities and therefore could be suggested as an effective part of treating and preventing RTIs. Based on published studies, the application of β-glucans was proven as a possible therapeutic and preventive approach in managing and preventing recurrent respiratory tract infections in children (especially β-glucans from Pleurotus ostreatus), adults (mostly the studies with yeast-derived β-glucans), and in elite athletes (studies with β-glucans from Pleurotus ostreatus or yeast).

PMID: 28726737 [PubMed - in process]

Categories: Literature Watch

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