The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Catharina Larsson - One of the best experts on this subject based on the ideXlab platform.
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a kindred with a variant of multiple endocrine neoplasia type 1 demonstrating frequent expression of pituitary tumors but not linked to the multiple endocrine neoplasia type 1 locus at chromosome region 11q13
The Journal of Clinical Endocrinology and Metabolism, 1997Co-Authors: John L Stock, Maria R Warth, Bin Tean Teh, James A Coderre, Judith H Overdorf, Gerhard Baumann, Raymond L Hintz, M L Hartman, Bernd R Seizinger, Catharina LarssonAbstract:Acromegaly is uncommon in kindreds with multiple endocrine neoplasia type 1 (MEN1), whereas primary hyperparathyroidism (PHP) has the highest penetrance of any endocrinopathy. We report an unusual MEN1 kindred with frequent expression of pituitary tumors and a low penetrance of PHP. Four members were found to have disease: PHP in Generation I, acromegaly (2 cases) in Generation Ii, and hyperprolactinemia associated with a pituitary tumor in Generation IiI. There was no evidence for PHP in 1 patient with acromegaly (age 60 yr), the patient with hyperprolactinemia and the pituitary tumor (age 22 yr), and 1 asymptomatic obligate carrier (age 50 yr). Screening of 26 members revealed the possible diagnosis of PHP in 1 family member in Generation Ii and possible early acromegaly in 2 members of Generation IiI with elevated serum concentrations of insulin-like growth factor I and insulin-like growth factor-binding protein-3 but normal patterns of pulsatile GH release. Although the predisposing genetic defect in ...
Carlos A Jerez - One of the best experts on this subject based on the ideXlab platform.
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growth of acidithiobacillus ferrooxidans atcc 23270 in thiosulfate under oxygen limiting conditions generates extracellular sulfur globules by means of a secreted tetrathionate hydrolase
Frontiers in Microbiology, 2011Co-Authors: Simon Beard, Alberto Paradela, Juan Pablo Albar, Carlos A JerezAbstract:Production of sulfur globules during sulfide or thiosulfate oxidation is a characteristic feature of some sulfur bacteria. Although their Generation has been reported in Acidithiobacillus ferrooxidans, its mechanism of formation and deposition, as well as the physiological significance of these globules during sulfur compounds oxidation, are currently unknown. Under oxygen sufficient conditions (OSC), A. ferrooxidans oxidizes thiosulfate to tetrathionate, which accumulates in the culture medium. Tetrathionate is then oxidized by a tetrathionate hydrolase (TTH) generating thiosulfate, elemental sulfur and sulfate as final products. We report here a massive production of extracellular conspicuous sulfur globules in thiosulfate-grown A. ferrooxidans cultures shifted to oxygen-limiting conditions (OLC). Concomitantly with sulfur globule deposition, the extracellular concentration of tetrathionate greatly diminished and sulfite accumulated in the culture supernatant. A. ferrooxidans cellular TTH activity was negligible in OLC incubated cells, indicating that this enzymatic activity was not responsible for tetrathionate disappearance. On the other hand, supernatants from both OSC- and OLC-incubated cells showed extracellular TTH activity, which most likely accounted for tetrathionate consumption in the culture medium. The extracellular TTH activity described here: (i) gives experimental support to the TTH-driven model for hydrophilic sulfur globule Generation, (Ii) explains the extracellular location of A. ferrooxidans sulfur deposits, and (Iii) strongly suggests that the Generation of sulfur globules in A. ferrooxidans corresponds to an early step during its adaptation to an anaerobic lifestyle.
Patricia L Foster - One of the best experts on this subject based on the ideXlab platform.
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rate and molecular spectrum of spontaneous mutations in the bacterium escherichia coli as determined by whole genome sequencing
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Heewook Lee, Ellen Popodi, Haixu Tang, Patricia L FosterAbstract:Knowledge of the rate and nature of spontaneous mutation is fundamental to understanding evolutionary and molecular processes. In this report, we analyze spontaneous mutations accumulated over thousands of Generations by wild-type Escherichia coli and a derivative defective in mismatch repair (MMR), the primary pathway for correcting replication errors. The major conclusions are (i) the mutation rate of a wild-type E. coli strain is ∼1 × 10−3 per genome per Generation; (Ii) mutations in the wild-type strain have the expected mutational bias for G:C > A:T mutations, but the bias changes to A:T > G:C mutations in the absence of MMR; (Iii) during replication, A:T > G:C transitions preferentially occur with A templating the lagging strand and T templating the leading strand, whereas G:C > A:T transitions preferentially occur with C templating the lagging strand and G templating the leading strand; (iv) there is a strong bias for transition mutations to occur at 5′ApC3′/3′TpG5′ sites (where bases 5′A and 3′T are mutated) and, to a lesser extent, at 5′GpC3′/3′CpG5′ sites (where bases 5′G and 3′C are mutated); (v) although the rate of small (≤4 nt) insertions and deletions is high at repeat sequences, these events occur at only 1/10th the genomic rate of base-pair substitutions. MMR activity is genetically regulated, and bacteria isolated from nature often lack MMR capacity, suggesting that modulation of MMR can be adaptive. Thus, comparing results from the wild-type and MMR-defective strains may lead to a deeper understanding of factors that determine mutation rates and spectra, how these factors may differ among organisms, and how they may be shaped by environmental conditions.
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rate and molecular spectrum of spontaneous mutations in the bacterium escherichia coli as determined by whole genome sequencing
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Ellen Popodi, Haixu Tang, Patricia L FosterAbstract:Knowledge of the rate and nature of spontaneous mutation is fundamental to understanding evolutionary and molecular processes. In this report, we analyze spontaneous mutations accumulated over thousands of Generations by wild-type Escherichia coli and a derivative defective in mismatch repair (MMR), the primary pathway for correcting replication errors. The major conclusions are (i) the mutation rate of a wild-type E. coli strain is ∼1 × 10−3 per genome per Generation; (Ii) mutations in the wild-type strain have the expected mutational bias for G:C > A:T mutations, but the bias changes to A:T > G:C mutations in the absence of MMR; (Iii) during replication, A:T > G:C transitions preferentially occur with A templating the lagging strand and T templating the leading strand, whereas G:C > A:T transitions preferentially occur with C templating the lagging strand and G templating the leading strand; (iv) there is a strong bias for transition mutations to occur at 5′ApC3′/3′TpG5′ sites (where bases 5′A and 3′T are mutated) and, to a lesser extent, at 5′GpC3′/3′CpG5′ sites (where bases 5′G and 3′C are mutated); (v) although the rate of small (≤4 nt) insertions and deletions is high at repeat sequences, these events occur at only 1/10th the genomic rate of base-pair substitutions. MMR activity is genetically regulated, and bacteria isolated from nature often lack MMR capacity, suggesting that modulation of MMR can be adaptive. Thus, comparing results from the wild-type and MMR-defective strains may lead to a deeper understanding of factors that determine mutation rates and spectra, how these factors may differ among organisms, and how they may be shaped by environmental conditions.
Shoshana Neuman - One of the best experts on this subject based on the ideXlab platform.
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the evolution of secularization cultural transmission religion and fertility theory simulations and evidence
Journal of Population Economics, 2013Co-Authors: Ronen Barel, Teresa Garciamunoz, Shoshana Neuman, Yossef TobolAbstract:This study presents an evolutionary process of secularization assuming that cultural/social/religious norms (in particular the ‘religious taste for children’) are transmitted from one Generation to the next via two venues: (i) direct socialization—across Generations, by parents; and (Ii) oblique socialization—within Generations, by the cultural environment. The paper integrates a theoretical model, simulations and an empirical estimation, that lead to the following main findings: (i) direct religious socialization efforts of one Generation have a negative effect on secularization within the next Generation; (Ii) oblique socialization by the community has a parabolic effect on secularization; and (Iii) the two types of socialization are complementary in ‘producing’ religiosity in the next Generation.
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the evolution of secularization cultural transmission religion and fertility theory simulations and evidence
Papers on Economics of Religion, 2010Co-Authors: Ronen Barel, Teresa Garciamunoz, Shoshana Neuman, Yossef TobolAbstract:This study presents an evolutionary process of secularization that integrates a theoretical model, simulations, and an empirical estimation that employs data from 32 countries (included in the International Social Survey Program: Religion Ii – ISSP, 1998). Following Bisin and Verdier (2000, 2001a), it is assumed that cultural/social norms are transmitted from one Generation to the next one via two venues: (i) direct socialization – across Generations, by parents; and (Ii) oblique socialization – within Generations, by the community and cultural environment. This paper focuses on the transmission of religious norms and in particular on the 'religious taste for children'. The theoretical framework describes the setting and the process leading to secularization of the population; the simulations give more insight into the process; and 'secularization regressions' estimate the effects of the various explanatory variables on secularization (that is measured by rare mass-attendance and by rare-prayer), lending support to corollaries derived from the theory and simulations. The main conclusions/findings are that (i) direct religious socialization efforts of one Generation have a negative effect on secularization within the next Generation; (Ii) oblique socialization by the community has a parabolic effect on secularization; and (Iii) the two types of socialization are complements in 'producing' religiosity of the next Generation.
Yossef Tobol - One of the best experts on this subject based on the ideXlab platform.
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the evolution of secularization cultural transmission religion and fertility theory simulations and evidence
Journal of Population Economics, 2013Co-Authors: Ronen Barel, Teresa Garciamunoz, Shoshana Neuman, Yossef TobolAbstract:This study presents an evolutionary process of secularization assuming that cultural/social/religious norms (in particular the ‘religious taste for children’) are transmitted from one Generation to the next via two venues: (i) direct socialization—across Generations, by parents; and (Ii) oblique socialization—within Generations, by the cultural environment. The paper integrates a theoretical model, simulations and an empirical estimation, that lead to the following main findings: (i) direct religious socialization efforts of one Generation have a negative effect on secularization within the next Generation; (Ii) oblique socialization by the community has a parabolic effect on secularization; and (Iii) the two types of socialization are complementary in ‘producing’ religiosity in the next Generation.
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the evolution of secularization cultural transmission religion and fertility theory simulations and evidence
Papers on Economics of Religion, 2010Co-Authors: Ronen Barel, Teresa Garciamunoz, Shoshana Neuman, Yossef TobolAbstract:This study presents an evolutionary process of secularization that integrates a theoretical model, simulations, and an empirical estimation that employs data from 32 countries (included in the International Social Survey Program: Religion Ii – ISSP, 1998). Following Bisin and Verdier (2000, 2001a), it is assumed that cultural/social norms are transmitted from one Generation to the next one via two venues: (i) direct socialization – across Generations, by parents; and (Ii) oblique socialization – within Generations, by the community and cultural environment. This paper focuses on the transmission of religious norms and in particular on the 'religious taste for children'. The theoretical framework describes the setting and the process leading to secularization of the population; the simulations give more insight into the process; and 'secularization regressions' estimate the effects of the various explanatory variables on secularization (that is measured by rare mass-attendance and by rare-prayer), lending support to corollaries derived from the theory and simulations. The main conclusions/findings are that (i) direct religious socialization efforts of one Generation have a negative effect on secularization within the next Generation; (Ii) oblique socialization by the community has a parabolic effect on secularization; and (Iii) the two types of socialization are complements in 'producing' religiosity of the next Generation.