bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mismatch: a comparative study of vitamin D status in British-Bangladeshi migrants
Authors: Smith Nicholas , Sievert Lynnette Leidy , Muttukrishna Shanthi , Begum Khurshida , Murphy Lorna , Sharmeen Taniya , Gunu Richard , Chowdhury Osul , Bentley Gillian R 
Published: January 2021

Abstract

Background and objectives
Low levels of vitamin D among dark-skinned migrants to northern latitudes and increased risks for associated pathologies illustrate an evolutionary mismatch between an environment of high ultraviolet (UV) radiation to which such migrants are adapted and the low UV environment to which they migrate. Recently, low levels of vitamin D have also been associated with higher risks for contracting COVID-19. South Asians in the UK have higher risk for low vitamin D levels. In this study, we assessed vitamin D status of British-Bangladeshi migrants compared with white British residents and Bangladeshis still living in Bangladesh (‘sedentees’).

Methodology
The cross-sectional study compared serum vitamin D levels among 149 women aged 35–59, comprising British-Bangladeshi migrants (n = 50), white British neighbors (n = 54) and Bangladeshi sedentees (n = 45). Analyses comprised multivariate models to assess serum levels of 25-hydroxyvitamin D (25(OH)D), and associations with anthropometric, lifestyle, health and migration factors.

Results
Vitamin D levels in Bangladeshi migrants were very low: mean 25(OH)D = 32.2 nmol/L ± 13.0, with 29% of migrants classified as deficient (&lt;25 nmol/L) and 94% deficient or insufficient (≤50 nmol/L). Mean levels of vitamin D were significantly lower among British-Bangladeshis compared with Bangladeshi sedentees (50.9 nmol/L ± 13.3, P &lt; 0.001) and were also lower than in white British women (55.3 nmol/L ± 20.9). Lower levels of vitamin D were associated with increased body mass index and low iron status.

Conclusions and implications
We conclude that lower exposure to sunlight in the UK reduces vitamin D levels in Bangladeshi migrants. Recommending supplements could prevent potentially adverse health outcomes associated with vitamin D deficiency.

Lay Summary
Vitamin D deficiency is one example of mismatch between an evolved trait and novel environments. Here we compare vitamin D status of dark-skinned British-Bangladeshi migrants in the UK to Bangladeshis in Bangladesh and white British individuals. Migrants had lower levels of vitamin D and are at risk for associated pathologies.
Alpha 1-adrenoceptor signalling contributes to toxic effects of catecholamine on electrical properties in cardiomyocytes
Authors: Huang Mengying , Fan Xuehui , Yang Zhen , Cyganek Lukas , Li Xin , Yuecel Goekhan , Lan Huan , Li Yingrui , Wendel Angela , Lang Siegfried , Bieback Karen , El-Battrawy Ibrahim , Zhou Xiaobo , Akin Ibrahim , Borggrefe Martin 
Published: January 2021

Abstract

Aims
This study aimed to investigate possible roles and underlying mechanisms of alpha-adrenoceptor coupled signalling for the pathogenesis of Takotsubo syndrome (TTS).

Methods and results
Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were treated with a toxic concentration of epinephrine (Epi, 0.5 mM for 1 h) to mimic the setting of TTS. Patch-clamp technique, polymerase chain reaction (PCR) and Fluorescence-activated cell sorting (FACS) were employed for the study. High concentration Epi suppressed the depolarization velocity, prolonged duration of action potentials and induced arrhythmic events in hiPSC-CMs. The Epi effects were attenuated by an alpha-adrenoceptor blocker (phentolamine), suggesting involvement of alpha-adrenoceptor signalling in arrhythmogenesis related to QT interval prolongation in the setting of TTS. An alpha 1-adrenoceptor agonist (phenylephrine) but not an alpha 2-adrenoceptor agonist (clonidine) mimicked Epi effects. Epi enhanced ROS production, which could be attenuated by the alpha- adrenoceptor blocker. Treatment of cells with H2O2 (100 µM) mimicked the effects of Epi on action potentials and a reactive oxygen species (ROS)-blocker (N-acetyl-I-cysteine, 1 mM) prevented the Epi effects, indicating that the ROS signalling is involved in the alpha-adrenoceptor actions. Nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidases were involved in alpha 1-adrenoceptor signalling. A protein kinase C (PKC) blocker suppressed the effects of Epi, phenylephrine and ROS as well, implying that PKC participated in alpha 1-adrenoceptor signalling and acted as a downstream factor of ROS. The abnormal action potentials resulted from alpha 1-adrenoceptor activation-induced dysfunctions of ion channels including the voltage-dependent Na+ and L-type Ca2+ channels.

Conclusions
Alpha 1-adrenoceptor signalling plays important roles for arrhythmogenesis of TTS. Alpha-adrenoceptor blockers might be clinically helpful for treating arrhythmias in patients with TTS.
Development and external validation of prediction models to predict implantable cardioverter-defibrillator efficacy in primary prevention of sudden cardiac death
Authors: Verstraelen Tom E , van Barreveld Marit , van Dessel Pascal H F M , Boersma Lucas V A , Delnoy Peter-Paul P H M , Tuinenburg Anton E , Theuns Dominic A M J , van der Voort Pepijn H , Kimman Gerardus P , Buskens Erik , Hulleman Michiel , Allaart Cornelis P , Strikwerda Sipke , Scholten Marcoen F , Meine Mathias , Abels René , Maass Alexander H , Firouzi Mehran , Widdershoven Jos W M G , Elders Jan , van Gent Marco W F , Khan Muchtiar , Vernooy Kevin , Grauss Robert W , Tukkie Raymond , van Erven Lieselot , Spierenburg Han A M , Brouwer Marc A , Bartels Gerard L , Bijsterveld Nick R , Borger van der Burg Alida E , Vet Mattheus W , Derksen Richard , Knops Reinoud E , Bracke Frank A L E , Harden Markus , Sticherling Christian , Willems Rik , Friede Tim , Zabel Markus , Dijkgraaf Marcel G W , Zwinderman Aeilko H , Wilde Arthur A M 
Published: January 2021

Abstract

Aims
This study was performed to develop and externally validate prediction models for appropriate implantable cardioverter-defibrillator (ICD) shock and mortality to identify subgroups with insufficient benefit from ICD implantation.

Methods and results
We recruited patients scheduled for primary prevention ICD implantation and reduced left ventricular function. Bootstrapping-based Cox proportional hazards and Fine and Gray competing risk models with likely candidate predictors were developed for all-cause mortality and appropriate ICD shock, respectively. Between 2014 and 2018, we included 1441 consecutive patients in the development and 1450 patients in the validation cohort. During a median follow-up of 2.4 (IQR 2.1–2.8) years, 109 (7.6%) patients received appropriate ICD shock and 193 (13.4%) died in the development cohort. During a median follow-up of 2.7 (IQR 2.0–3.4) years, 105 (7.2%) received appropriate ICD shock and 223 (15.4%) died in the validation cohort. Selected predictors of appropriate ICD shock were gender, NSVT, ACE/ARB use, atrial fibrillation history, Aldosterone-antagonist use, Digoxin use, eGFR, (N)OAC use, and peripheral vascular disease. Selected predictors of all-cause mortality were age, diuretic use, sodium, NT-pro-BNP, and ACE/ARB use. C-statistic was 0.61 and 0.60 at respectively internal and external validation for appropriate ICD shock and 0.74 at both internal and external validation for mortality.

Conclusion
Although this cohort study was specifically designed to develop prediction models, risk stratification still remains challenging and no large group with insufficient benefit of ICD implantation was found. However, the prediction models have some clinical utility as we present several scenarios where ICD implantation might be postponed.
Settlers of our inner surface – factors shaping the gut microbiota from birth to toddlerhood
Authors: Laursen Martin Frederik , Bahl Martin Iain , Licht Tine Rask 
Published: January 2021

ABSTRACTDuring the first 3 years of life, the microbial ecosystem within the human gut undergoes a process that is unlike what happens in this ecosystem at any other time of our life. This period in time is considered a highly important developmental window, where the gut microbiota is much less resilient and much more responsive to external and environmental factors than seen in the adult gut. While advanced bioinformatics and clinical correlation studies have received extensive focus within studies of the human microbiome, basic microbial growth physiology has attracted much less attention, although it plays a pivotal role to understand the developing gut microbiota during early life. In this review, we will thus take a microbial ecology perspective on the analysis of factors that influence the temporal development of the infant gut microbiota. Such factors include sources of microbes that seed the intestinal environment, physico-chemical (abiotic) conditions influencing microbial growth and the availability of nutrients needed by the intestinal microbes.
First Complete Genome of the Thermophilic Polyhydroxyalkanoates-Producing Bacterium Schlegelella thermodepolymerans DSM 15344
Authors: Musilova Jana , Kourilova Xenie , Bezdicek Matej , Lengerova Martina , Obruca Stanislav , Skutkova Helena , Sedlar Karel 
Published: January 2021

Abstract
Schlegelella thermodepolymerans is a moderately thermophilic bacterium capable of producing polyhydroxyalkanoates—biodegradable polymers representing an alternative to conventional plastics. Here, we present the first complete genome of the type strain S. thermodepolymerans DSM 15344 that was assembled by hybrid approach using both long (Oxford Nanopore) and short (Illumina) reads. The genome consists of a single 3,858,501-bp-long circular chromosome with GC content of 70.3%. Genome annotation identified 3,650 genes in total, whereas 3,598 open reading frames belonged to protein-coding genes. Functional annotation of the genome and division of genes into clusters of orthologous groups revealed a relatively high number of 1,013 genes with unknown function or unknown clusters of orthologous groups, which reflects the fact that only a little is known about thermophilic polyhydroxyalkanoates-producing bacteria on a genome level. On the other hand, 270 genes involved in energy conversion and production were detected. This group covers genes involved in catabolic processes, which suggests capability of S. thermodepolymerans DSM 15344 to utilize and biotechnologically convert various substrates such as lignocellulose-based saccharides, glycerol, or lipids. Based on the knowledge of its genome, it can be stated that S. thermodepolymerans DSM 15344 is a very interesting, metabolically versatile bacterium with great biotechnological potential.
COMPENSATORY REGULATION OF TWO CLOSELY RELATED HEMOGLOBIN LOCI IN CHIRONOMUS TENTANS
Authors: Thompson Peter , Patel Gordhan 
Published: January 2021

ABSTRACT
Regulatory mutants in the hemoglobin system of Chironomus larvae can be detected by shifts in the relative quantity of specific components among the 10-12 mixed monomers. One such mutant, at or near a hemoglobin structural locus in the right tip of chromosome 3, greatly increases the quantity of that minor hemoglobin and greatly diminishes the quantity of the hemoglobin normally most abundant. Heterozygotes for the mutant are quantitatively intermediate, suggesting a transcriptional basis.—Structural similarities of the two hemoglobins indicate a close evolutionary relationship, and their interdependent but non-coordinate regulation is interpreted as competition for a common factor which functions in transcription. If evolutionary duplication of both structural genes and promotors is assumed, this factor may be a sigma subunit of RNA polymerase which recognizes similar but non-identical promotor regions. Parallels in the compensatory control of human hemoglobins are described.
RNA SYNTHESIS AND HETEROCHROMATIZATION IN EARLY DEVELOPMENT OF A MEALYBUG
Authors: Sabour Mohammad 
Published: January 2021

ABSTRACT
Microinjection of specific radioisotope tracers showed that DNA and protein synthesis are triggered by fertilization but nuclear RNA synthesis does not occur until the cleavage nuclei migrate to the periphery. In the male, heterochromatization of the paternal chromosome set also occurs when the cleavage nuclei reach the periphery. These results help to explain those of several types of genetic test, especially the failure of typical dominant lethal induction in the heterochromatized set.
THE LOCATION OF VIABILITY GENES WITHIN A TESTCROSS FRAMEWORK
Authors: Chapco William 
Published: January 2021

ABSTRACT
The maximum likelihood method is applied to the problem of estimating the positions and effects of viability genes. Whenever testcross linkage data indicate the presence of differential viability, it is hypothesized that there exists one viability gene between each marker. Estimation is possible only for two-point data since the number of independent expectation expressions is less than the number of parameters for three or more markers. It is pointed out that within the two-point testcross system, it is impossible to distinguish between pleiotropic effects of the marker genes and the effect of a middle viability gene, if existent. The methods outlined will be useful in their application to experiments specifically designed to locate induced viability genes.
A STUDY OF SPONTANEOUS MUTATION RATES AT TEN LOCI DETECTABLE BY STARCH GEL ELECTROPHORESIS IN DROSOPHILA MELANOGASTER
Authors: Tobari Yoshiko N , Kojima Ken-Ichi 
Published: January 2021

ABSTRACT
Spontaneous mutation rates at ten allozyme loci on chromosomes II and III of Drosophila melanogaster were studied. Over the three and a half years study, one α-GPD mutation and two different IDH mutations were obtained. The α-GPD mutation was inherited in the Mendelian fashion, as expected. The two IDH mutations were peculiar in that the band of new types appeared only in females. In males, only the original bands were stained, and the positions where mutant alleles' bands should be present were blank. Both IDH mutant homozygotes appeared as null allele homozygotes, while in females clear-cut single bands were present.—The rates of spontaneous mutation varied greatly. Eight loci studied (MDH, ADH, EST-6, APH, EST-C, ODH, XDH, AO) did not give any germ-line mutation. The average germ-line mutation rate over all ten loci was estimated at 4.5 × 10-6. This rate is considerably smaller than that for sex-linked recessive visible mutations (Muller, Valencia and Valencia 1950), but it is somewhat less than autosomal recessive visible mutations (Glass and Ritterhoff 1956).
THE ADDITION OF LAC+ CHROMOSOME FRAGMENTS TO THE E. COLI PROA—PROB—LAC DELETION XIII CHROMOSOME
Authors: Stodolsky M , Rae M Engel , Mullenbach E 
Published: January 2021

ABSTRACT
Escherichia coli with the proA–proB–lac deletion ×111 (Δ111) can be transduced with bacteriophage P1 propagated on a wild-type lac + donor. Though the donor lac + genes cannot be integrated by replacement of the recipient Δ111 marker, the transduction process has the characteristics generally associated with generalized transduction of bacterial genes. Transduction does not require P1 helper infection, is stimulated by UV irradiation of transducing particles, and does require homology between the donor lac + chromosome and the recipient Δ111 chromosome. Among transductants produced through multiple P1 infection, a minority of P1 dl lysogens are present. But the majority of the transductants have unstable lac + units, designated lac V, which are without detected P1 gene content. LacV is tightly linked to the Δ111 locus. Instability of lac + is eliminated when a recombination deficiency is introduced through a substitution of recA1 for rec +. The properties of the Δ111/lacV strains are attributable to a chromosome in which lac + is situated between units of a genetic duplication beside the Δ111 locus. To explain the formation of partially diploid chromosomes we suggest that chromosome fragment integration is sometimes accomplished through a single aberrant recombination, a fusion of genetically heterologous DNA ends, and a single legitimate crossover.
FACTORS AFFECTING RECOGNITION AND DISJUNCTION OF CHROMOSOMES AT DISTRIBUTIVE PAIRING IN FEMALE DROSOPHILA MELANOGASTER. I. TOTAL LENGTH VS. ARM LENGTH
Authors: Moore Charleen M , Grell Rhoda F 
Published: January 2021

ABSTRACT
The behavior of a compound metacentric fourth chromosome (see PDF) has been examined to determine whether arm length or total length is the basis for recognition in distributive pairing. Recognition was judged by the frequency with which the (see PDF) nondisjoined from a series of X duplications (Dp), ranging in size from ≤ 0.3 to &gt; 4 times the size of a single fourth chromosome. Dp, (see PDF) nondisjunction was measured in the absence and in the presence of a competitor, a compound metacentric X. In both situations, total length and not arm length, was found to confer the characteristic recognition property to the (see PDF). A comparison of Dp, (see PDF) nondisjunction curves for both the noncompetitive and competitive situations with analogous Dp, 4 curves previously obtained, show the Dp, (see PDF) curves to be similar in shape to those obtained earlier but displaced one unit to the right, corresponding precisely to the difference in size between the (see PDF) and the 4. Rules governing chromosome recognition for acrocentrics were found completely applicable to metacentrics; disjunctive behavior of metacentrics differed from that of acrocentrics in that two arms conferred on a chromosome the capacity to act as the intermediate of a trivalent when size no longer warranted this attribute. This capacity, itself, is size-dependent.
POPULATION GENETICS OF LEBISTES (POECILIA) RETICULATUS PETERS (POECILIIDAE; PISCES). I. EFFECTS OF RADIATION-INDUCED MUTATIONS ON THE SEGREGATION RATIO IN POSTIRRADIATION F2
Authors: Schröder Johannes Horst , Holzberg Sebastian 
Published: January 2021

ABSTRACT
Wild-type germ cells of the viviparous fish, Lebistes (Poecilia) reticulatus, were irradiated in the stages of oogonia, spermatogonia or spermatozoa with 1000 R of X rays at a dose-rate of 200–220 R/min. The grown-up fish were mated after irradiation or sham treatment to unirradiated mutant fish homozygous for three recessive gene loci, causing albinism, lack of yellow and reddish pigmentation ("blue" constitution), and diminution of the size of melanophores ("blond" constitution). As compared to the control series, the phenotypic segregation ratios in the adult F2 generation after irradiation was changed significantly in favour of wild-type and blue fish, whereas the proportion of albinotic, blond and "white" (= blond + blue) guppies was lowered. This unidirectional effect in postirradiation F2 was greatest after exposure of spermatozoa with 2 × 500 R (24 hr apart), followed by single doses of 1000 R to spermatogonia and oogonia. These results were explained in terms of a synergistic interaction of recessive radiation-induced mutations in the heterozygous state with those genotypes of the guppy which affect the formation of melanophoric patterns and the synthesis of melanins.
CHROMOSOME PAIRING IN MAIZE
Authors: Burnham Charles R , Stout John T , Weinheimer William H , Kowles Richard V , Phillips Ronald L 
Published: January 2021

ABSTRACT
This report summarizes our observations at pachytene on opposite-arms intercrosses between stocks of interchanges that involve chromosomes 1 and 5 in maize.—Pairing does not begin at the centromeres in these intercrosses.—We propose a model which assumes different probability values along each chromosome arm for the initial or primary site of pairing. Observations on the frequencies of the different types of configurations at pachytene were used to estimate probability values which satisfactorily fit the data.—There is a relatively low probability (of the order of.1 to.3) for the initial pairing to be in a short terminal segment (about.1 of the arm length). Initial pairing in the one or two short segments adjacent to the tip segment is much higher. Initial pairing is much lower in segments successively closer to the middles of the chromosome arms, and then zero or nearly zero in the proximal half of the arm. This means that the initial pairing may fail occasionally even in a relatively long interchanged segment and produce a T-shaped (3-armed) configuration.—After the initial pairing has occurred, the average probability that a secondary site of pairing is adjacent to the centromere in a segment.3 to.4 the length of an arm is low (.13, ranging from.02 to.29).—We can predict that in an intercross in which both breakpoints in both parental interchanges are far out on the chromosomes, "pairs" will be formed with nonhomologous ends (homologous differential segments paired). In these pairing could have begun at any point in the interstitial segments, but not likely in segments close to the centromeres.—Multiple secondary sites which vary in time or in order of pairing will explain the variation in position of the cross-shaped pachytene configuration in interchange heterozygotes.—The observed configuration in any one cell is the result of a particular combination of pairing events at the various sites. This is a very different concept of pairing from previous interpretations which described it as a result of zipper-like action, and the variation in position of the pachytene cross-configuration as the result of "shifts" in position.—Our cytogenetic results and their interpretation are in close agreement with reports on chromosome ultrastructure and molecular events in the early stages of meiosis, i.e. the attachment of chromosome ends to the nuclear membrane, the manner in which synaptonemal complexes develop, and the regions of DNA whose replication is delayed until zygonema.
THE α-GLYCEROPHOSPHATE IN DROSOPHILA MELANOGASTER II. GENETIC ASPECTS
Authors: O'Brien Stephen J , Macintyre Ross J 
Published: January 2021

ABSTRACT
Seven alleles of the α-Glycerophosphate dehydrogenase-1 (αGpdh-1) locus of Drosophila melanogaster have been described. These include two naturally occurring electrophoretic variants, one EMS-induced electrophoretic variant, and four EMS-induced "null" or "zero" mutants. With the electrophoretic variants, the locus was mapped to II-20.5 ± 2.5. A complementation matrix was prepared utilizing the null mutants. Three of the four mutants and a deletion of the locus (Grell 1967) exhibit dosage dependency. The dosage independent mutant exhibits complementation with two of the other null alleles. Flies genetically deficient in α-glycerophosphate dehydrogenase are fertile, but their relative viability is severely diminished. Such flies also lose the ability to sustain flight, an observation consistent with the enzyme's function in energy production. The levels of mitochondrial α-glycerophosphate oxidase, measured in flies genetically deficient in the cytoplasmic enzyme, were normal.
ON SOME GENETIC ASPECTS OF PHAGE Λ RESISTANCE IN E. COLI K12
Authors: Thirion J P , Hofnung M 
Published: January 2021

ABSTRACT
Most mutations rendering E. coli K12 resistant to phage λ, map in two genetic regions mal A and mal B.—The malB region contains a gene lamB specifically involved in the λ receptor synthesis. Twenty-one independent lamB mutations studied by complementation belonged to a single cistron. This makes it very likely that lamB is monocistronic. Among the lamB mutants some are still sensitive to a host range mutant of phage λ. Mutations mapping in a proximal gene essential for maltose metabolism inactivate gene lamB by polarity confirming that both genes are part of the same operon. Because cases of intracistronic complementation have been found, the active lamB product may be an oligomeric protein.—Previously all λ resistant mutations in the malA region have been shown to map in the malT cistron. malT is believed to be a positive regulatory gene necessary for the induction of the "maltose operons" in the malA region and in the malB region of the E. coli K12 genetic map. No trans dominant malT mutation have been found. Therefore if they exist, they occur at a frequency of less than 10–8, or strongly reduce the growth rate of the mutants.