bluuebunny/crossref_metadata_2025_split huggingface dataset:
TWO MULTIALLELIC MATING COMPATIBILITY LOCI SEPARATELY REGULATE ZYGOTE FORMATION AND ZYGOTE DIFFERENTIATION IN THE MYXOMYCETE PHYSARUM POLYCEPHALUM
Authors: Youngman Philip J , Anderson Roger W , Holt Charles E 
Published: April 2021

ABSTRACT
The mating of Physarum polycephalum amoebae, the ultimate consequence of which is a "plasmodium," was recently shown to be governed by two compatibility loci, matA (or mt) and matB (DEE1 978; YOUNGMAeNt aZ. 1979), We present evidence that matA and matB separately regulate two discrete stages of mating: in the first stage, amoebae (which are normally haploid) fuse in pairs, with a specificity determined by matB genotype, to form diploid zygotes; subsequent differentiation of the zygotes into plasmodia is regulated by matA and is unaffected by matB. Mixtures of amoebae carrying unlike matA and matB alleles formed diploids to the extent of 10 to 15% of the cells present, and the diploids differentiated into plasmodia. When only the matB alleles differed, diploid cells still formed to a comparable (5 to 101%) extent, but rather than differentiating, these diploids remained amoebae. When strains carried the same alleles of matB, formation of diploid cells was greatly reduced: in like matB, like-matd mixtures, none of 320 cells examined was diploid; in like maiB, unlike mat-A mixtures, differentiating diploids could be detected, but at only IO-3 to 10-2 the frequency of unlike-matB, unlike-matA mixtures. The nondifferentiating diploid amoebae recovered from unlike-matB, like-matA mixtures were genetically stable through extensive growth, even though they grew more slowly than haploids (10-hr us. 8-hr doubling period), and could be crossed with both haploids and diploids. The results of such higher ploidy and mixed ploidy crosses indicate that karyogamy does not invariably accompany zygote formation and differentiation.
THIRD-CHROMOSOME MUTAGEN-SENSITIVE MUTANTS OF DROSOPHILA MELANOGASTER
Authors: Boyd J B , Golino M D , Shaw K E S , Osgood C J , Green M M 
Published: April 2021

ABSTRACT
A total of 34 third chromosomes of Drosophila melanogaster that render homozygous larvae hypersensitive to killing by chemical mutagens have been isolated. Genetic analyses have placed responsible mutations in more than eleven complementation groups. Mutants in three complementation groups are strongly sensitive to methyl methanesulfonate, those in one are sensitive to nitrogen mustard, and mutants in six groups are hypersensitive to both mutagens. Eight of the ten loci mapped fall within 15% of the genetic map that encompasses the centromere of chromosome 3. Mutants from four of the complementation groups are associated with moderate to strong meiotic effects in females. Preliminary biochemical analyses have implicated seven of these loci in DNA metabolism.
GENETICS OF FERTILITY RESTORATION IN THE C-GROUP OF CYTOPLASMIC MALE STERILITY IN MAIZE
Authors: Kheyr-Pour A , Gracen V E , Everett H L 
Published: April 2021

ABSTRACT
The genetics of fertility restoration of cms-C group cytoplasm of maize was studied using crosses involving stable maintainer lines and lines that restored full pollen fertility. Pollen fertility in the sources of cms-C sterile cytoplasms studied was restored by a single dominant restorer (Rf4) gene. The fertility restoration was sporophytic. Allelism tests among five restorer lines showed that they all apparently carried the same alleles (Rf4 Rf4). Similar tests also demonstrated that seven nonrestoring maintainer lines had apparently the same genotype (rf4 rf4), although a partial "late break" of fertility was observed at low levels in some maintainer crosses. Comparative studies among different cms-C sources (C, Bb, ES, PR and RB) indicated that similar inheritance of fertility restoration was involved. The data indicated that a single, dominant Rf gene is involved in the restoration of several C-group cytoplasms, at least in the lines studied here. This is the first single-gene, sporophytic restorer system described in maize to date.
GERMLINE HYPERMUTABILITY IN DROSOPHILA AND ITS RELATION TO HYBRID DYSGENESIS AND CYTOTYPE
Authors: Engels William R 
Published: April 2021

ABSTRACT
In its hypermutable state, an unstable singed allele, snw, mutates in the germline to two other alleleic forms at a total frequency usually between 40 and 60%. In its stable state, the mutation rate of snw is essentially zero. Its state depends on an extrachromosomal condition indistinguishable from a property called cytotype previously studied as a component of hybrid dysgenesis. Of the two known systems of hybrid dysgenesis, denoted P-M and I-R, snw hypermutability is determined by the P-M system and appears to be independent of the I-R system. Cytotype, as defined by the control of snw mutability, is self-reproducing in the cytoplasm or nucleoplasm of the germline through at least two generations. However, it is not entirely autonomous, being ultimately determined by the chromosomes after sufficiently many generations of backcrossing. This combination of chromosomal and extrachromosomal transmission agrees well with previous studies on cytotype. Temperature differences have little effect on the mean mutation rates, but they have a pronounced effect on the intrinsic variance among individuals. The latter effect suggests that high temperatures reduce germ-cell survival during the development of dysgenic flies. Chromosomal rearrangements produce no apparent effects on the behavior of snw. Hypermutability is thought to be caused by the excision or other alteration of an inserted genetic element in the snw gene. This element might be a copy of the "P factor," which is though to be a mobile sequence capable of causing female sterility and other dysgenic traits in the P-M system.
GENETIC DRIFT AND ESTIMATION OF EFFECTIVE POPULATION SIZE
Authors: Nei Masatoshi , Tajima Fumio 
Published: April 2021

ABSTRACT
The statistical properties of the standardized variance of gene frequency changes (a quantity equivalent to Wright's inbreeding coefficient) in a random mating population are studied, and new formulae for estimating the effective population size are developed. The accuracy of the formulae depends on the ratio of sample size to effective size, the number of generations involved (t), and the number of loci or alleles used. It is shown that the standardized variance approximately follows the Χ2 distribution unless t is very large, and the confidence interval of the estimate of effective size can be obtained by using this property. Application of the formulae to data from an isolated population of Dacus oleae has shown that the effective size of this population is about one tenth of the minimum census size, though there was a possibility that the procedure of sampling genes was improper.
AGENTS THAT CAUSE A HIGH FREQUENCY OF GENETIC CHANGE FROM [psi
+] TO [psi
-] IN SACCHAROMYCES CEREVISIAE
Authors: Tuite M F , Mundy C R , Cox B S 
Published: April 2021

ABSTRACT
The [psi] factor of yeast is cytoplasmically inherited. Singh, Helms and Sherman (1979) reported that high concentrations of KCl and of ethylene glycol induce the genetic change from [psi +] to [psi -]. In this study, the following agents have been shown to induce the same genetic change: guanidine hydrochloride at 1 mm, dimethyl sulfoxide at 2.5% v/v and ethanol or methanol at 10% v/v. It is likely that a number of other agents also cause the change, namely 2 m glycerol, m succinate, m glutamate and m MgCl2. Most of these agents induce the change at very high frequencies; with some, the frequency is 100%. Although the observed phenotypic change can also occur as a result of chromosomal gene mutation, no changes of this type were identified. Some of the agents also cause mutation from [rho +] to [rho -] and from killer to sensitive.
AUTOSOMAL FACTORS WITH CORRELATED EFFECTS ON THE ACTIVITIES OF THE GLUCOSE 6-PHOSPHATE AND 6-PHOSPHOGLUCONATE DEHYDROGENASES IN DROSOPHILA MELANOGASTER
Authors: Laurie-Ahlberg C C , Williamson J H , Cochrane B J , Wilton A N , Chasalow F I 
Published: April 2021

ABSTRACT
Isogenic lines, in which chromosomes sampled from natural populations of D. melanogaster are substituted into a common genetic background, were used to detect and partially characterize autosomal factors that affect the activities of the two pentose phosphate pathway enzymes, glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD). The chromosome 3 effects on G6PD and 6PGD are clearly correlated; the chromosome 2 effects, which are not so great, also appear to be correlated, but the evidence in this case is not so strong. Examination of activity variation of ten other enzymes revealed that G6PD and 6PGD are not the only pair of enzymes showing a high positive correlation, but it is among the highest in both sets of lines. In addition, there was some evidence that the factor(s) affecting G6PD and 6PGD may also affect two other metabolically related enzymes, transaldolase and phosphoglucose isomerase.—Rocket immunoelectrophoresis was used to estimate specific CRM levels for three of the enzymes studied: G6PD, 6PGD and ME. This experiment shows that a large part of the activity variation is accounted for by variation in CRM level (especially for chromosome 3 lines), but there remains a significant fraction of the genetic component of activity variation that is not explained by CRM level.—These results suggest that the autosomal factors are modifiers involved in regulation of the expression of the X-linked structural genes for G6PD and 6PGD, but a role in determining part of the enzymes′ primary structure cannot be excluded with the present evidence.
MODULATION OF PROTEIN LEVELS IN CHROMOSOMAL DOSAGE SERIES OF MAIZE: THE BIOCHEMICAL BASIS OF ANEUPLOID SYNDROMES
Authors: Birchler James A , Newton Kathleen J 
Published: April 2021

ABSTRACT
Genetically defined dosage series of chromosome arms 1L, 3L, 4S, 5L, 7L, 9S, 10L and combinations of 1L-3L, collectively spanning approximately one-third of the maize genome, were examined for alterations in the expression of total protein profiles in scutellar tissue. The major effects found were negative correlations of specific proteins with the dosage of particular regions in a manner similar to that previously described for enzyme activity levels (Birchler 1979). Chromosome arms 1L, 4S and 5L produced the most severe negative effects, with 3L and 7L exhibiting this phenomenon to a lesser degree. Positive correlations of certain proteins were observed with the dosage of the 1L, 3L, 5L and 7L regions. The structural locus of one of the major scutellar proteins (PRO) is present in the long arm of chromosome 1 (Schwartz 1979), but exhibits compensation in a dosage series involving whole-arm comparisons. Multiple factors in 1L affect the level of the protein. The compound TB-1La-3L4759-3 (1L 0.20-0.39) has a slight negative effect on PRO, while TB-1La-3Le (1L 0.20-0.58) and TB-1La-3L5267 (1L 0.20-0.72) have a more pronounced negative influence. The level of this protein is not altered by the dosage of 3L. These observations suggest that compensation is brought about by the cancellation of a positive structural gene dosage effect by the negative inverse effect. Other regions of the genome that contribute to the control of PRO levels are 4S and 5L. Total protein profiles were also compared in haploid, diploid and tetraploid maize as a comparison to the aneuploid series. Most proteins exhibit structural-gene-dosage effects through the ploidy series, but others show a positive effect greater than expected from varying the structural genes. Still others are negatively affected by ploidy changes. In general, the ploidy alterations are not as great as predicted from the cumulative action of the aneuploid effects. The bearing of these observations on the biochemical basis of aneuploid syndromes is discussed.
ANALYSIS OF A CONTROLLING-ELEMENT MUTATION AT THE Adh LOCUS OF MAIZE
Authors: Osterman John C , Schwartz Drew 
Published: April 2021

ABSTRACT
A Ds-suppressed Adh mutant was isolated by the allyl alcohol pollen selection technique. The mutant produces a reduced level of an altered thermolabile enzyme suggesting that the Ds element is inserted in the Adh structural gene. The mutant protein is enzymatically active and does not differ detectably in size from the progenitor protein. A number of possible explanations for the data are presented.
NET GENETIC AND TEMPORARY EPISTATIC OR MATERNAL ENVIRONMENTAL RESPONSES TO SELECTION FOR EGG PRODUCTION IN CHICKENS
Authors: Bennett G L , Dickerson G E , Gowe R S , McAllister A J , Emsley J A B 
Published: April 2021

ABSTRACT
The difference between progeny from selected and unselected parents (T) was experimentally partitioned into net genetic change (GA), temporary favorable epistatic combinations (GEP) and egg-transmitted maternal environment (M) in two strains of Leghorns selected over 14 years for early pure-strain egg production. Differences among progeny from selected sires and dams, selected sires only, selected dams only, unselected sires and dams and the parental generation were equated to expected GA, GEP and M responses for each trait. Total response was 3.3% for early egg number, 3.7% for total egg number, 0.5% for egg weight, 3.8% for early egg mass and 4.2% for total egg mass. Among progeny that survived the test period and were judged to be normal, total response was 2.6% for total number of eggs, 3.0% for early egg mass and 3.1% for total egg mass. The percentage of T attributed to GA was 9% for early egg number, 24% for total egg number, 43% for early egg mass and 47% for total egg mass; but 52% for total egg number, 98% for early egg mass and 71% for total egg mass of normal survivors. Temporary maternal selection responses (M) were (1) positive for number of eggs and egg masses, (2) greater for all progeny than for normal survivors, and (3) increased with progeny age. The results suggest that M was caused by reduced egg-transmitted disease. Epistatic selection response was positive for earlier sexual maturity and for number of eggs, but negative for egg weight and thus was small for egg masses. Temporary epistatic and maternal responses can explain overestimation of additive genetic response from offspring-parent regression or from replicated single-generation selection and apparent superiority of mass selection over family or combined selection.
GENETICALLY INDUCED MITOTIC EXCHANGE IN THE HETEROCHROMATIN OF DROSOPHILA MELANOGASTER
Authors: Robbins Leonard G 
Published: April 2021

ABSTRACT
Multiple copies of the 18s and 28sribosomal RNA cistrons are present in both the Xand Y chromosomes of Drosophila melanogaster.Data are presented here that identify a locus, Rex,that causes exchange-like events between duplicated ribosomal complexes at the ends of an attached-XY chromosome. Rex:(1) is close to or in the basal heterochromatin of the Xchromosome; (2)is semidominant and (its effect) is temperature sensitive; (3) acts maternally; and (4) affects behavior of paternally derived attached-XY chromosomes shortly after fertilization. Though, at this point, the existence of Rexis known only from its effects on behavior of a particular compound chromosome, it presents intriguing possibilities for understanding regulation of chromosome behavior and organization of the ribosomal cistrons.
A duplication on chromosome 16q12 affecting theIRXBgene cluster is associated with autosomal dominant cone dystrophy with early tritanopic color vision defect
Authors: Kohl Susanne , Llavona Pablo , Sauer Alexandra , Reuter Peggy , Weisschuh Nicole , Kempf Melanie , Dehmelt Florian Alexander , Arrenberg Aristides B , Sliesoraityte Ieva , Zrenner Eberhart , van Schooneveld Mary J , Rudolph Günther , Kühlewein Laura , Wissinger Bernd 
Published: April 2021

AbstractCone dystrophies are a rare subgroup of inherited retinal dystrophies and hallmarked by color vision defects, low or decreasing visual acuity and central vision loss, nystagmus and photophobia. Applying genome-wide linkage analysis and array comparative genome hybridization, we identified a locus for autosomal dominant cone dystrophy on chromosome 16q12 in four independent multigeneration families. The locus is defined by duplications of variable size with a smallest region of overlap of 608 kb affecting the IRXB gene cluster and encompasses the genes IRX5 and IRX6. IRX5 and IRX6 belong to the Iroquois (Iro) protein family of homeodomain-containing transcription factors involved in patterning and regionalization of embryonic tissue in vertebrates, including the eye and the retina. All patients presented with a unique progressive cone dystrophy phenotype hallmarked by early tritanopic color vision defects. We propose that the disease underlies a misregulation of the IRXB gene cluster on chromosome 16q12 and demonstrate that overexpression of Irx5a and Irx6a, the two orthologous genes in zebrafish, results in visual impairment in 5-day-old zebrafish larvae.
Quantification of persister formation ofEscherichia colileveraging electronic cell counting and semi-mechanistic pharmacokinetic/pharmacodynamic modelling
Authors: Seeger Johanna , Michelet Robin , Kloft Charlotte 
Published: April 2021

AbstractBackgroundPersister formation of Escherichia coli under fluoroquinolone exposure causes treatment failure and promotes emergence of resistant strains. Semi-mechanistic pharmacokinetic/pharmacodynamic modelling of data obtained from in vitro infection model experiments comprehensively characterizes exposure–effect relationships, providing mechanistic insights.ObjectivesTo quantify persister formation of E. coli under levofloxacin exposure and to explain the observed growth-kill behaviour, leveraging electronic cell counting and pharmacokinetic/pharmacodynamic modelling.MethodsThree fluoroquinolone-resistant clinical E. coli isolates were exposed to levofloxacin in static and dynamic in vitro infection model experiments. Complementary to plate counting, bacterial concentrations over time were quantified by electronic cell counting and amalgamated in a semi-mechanistic pharmacokinetic/pharmacodynamic model (1281 bacterial and 394 levofloxacin observations).ResultsBacterial regrowth was observed under exposure to clinically relevant dosing regimens in the dynamic in vitro infection model. Electronic cell counting facilitated identification of three bacterial subpopulations: persisters, viable cells and dead cells. Two strain-specific manifestations of the levofloxacin effect were identified: a killing effect, characterized as a sigmoidal Emax model, and an additive increase in persister formation under levofloxacin exposure. Significantly different EC50 values quantitatively discerned levofloxacin potency for two isolates displaying the same MIC value: 8 mg/L [EC50 = 17.2 (95% CI = 12.6–23.8) mg/L and 8.46 (95% CI = 6.86–10.3) mg/L, respectively]. Persister formation was most pronounced for the isolate with the lowest MIC value (2 mg/L).ConclusionsThe developed pharmacokinetic/pharmacodynamic model adequately characterized growth-kill behaviour of three E. coli isolates and unveiled strain-specific levofloxacin potencies and persister formation. The mimicked dosing regimens did not eradicate the resistant isolates and enhanced persister formation to a strain-specific extent.
Stress-constrained topology optimization for material extrusion polymer additive manufacturing
Authors: Liu Jikai , Yan Jingjing , Yu Huangchao 
Published: April 2021

Abstract
This paper presents a comprehensive numerical and experimental study on stress-constrained topology optimization for Fused Deposition Modeling (FDM) additive manufacturing. The qp method is employed to avoid the singularity issue of stress-constrained problems. The P-norm function with stability transformation is adopted to build the global stress constraint with iterative corrections to eliminate the gap between the maximum local stress and the P-norm stress. The Heaviside projection is employed to generate clear-cut 0–1 designs. Two benchmark examples have been studied with the numerical algorithm. Experiments are performed on the topologically optimized MBB beam to investigate the impact of the FDM process parameters, including deposition path direction, building direction, and slicing layer height, on the resulted structural strength. The stress-constrained designs without and with Heaviside projection are comparatively tested with experiments. The stress-minimization designs subject to different P-norm parameters are compared both numerically and experimentally. Experiments show that the deposition path direction and the building direction evidently affect the derived structural strength. Moreover, overthin structural members may severely degrade the structural strength due to manufacturing and loading uncertainties.
Syntax and the Illusion of Fit: How Grammatical Subject Influences Persuasion
Authors: Ostinelli Massimiliano , Luna David 
Published: April 2021

Abstract
We examine how the grammatical subject of a marketing claim affects persuasion. We refer to this phenomenon as the subject bias and introduce the distinction between users subjects (where product users are the grammatical subject of a sentence) and product subjects (where the product is the grammatical subject of the sentence). We find that users subjects can lead to an illusion of fit, where a reader believes that an offer provides a better fit for oneself than for other consumers, which, in turn, affects persuasion. Eight experiments, including a field study, provide support for the subject bias in different domains, ranging from online dating services to medical products, and uncover the underlying process along with its boundary conditions while ruling out alternative explanations. These findings advance the understanding of the antecedents and consequences of idiosyncratic fit and introduce a novel language effect in consumer research that has theoretical, methodological, and practical implications.
On the Form and Origins of the Bizarre Sex Chromosomal System of the Mandarin Vole
Authors: Roy Scott William 
Published: April 2021

AbstractRecent work has illuminated the bizarre sex chromosomal system of the mandarin vole, Lasiopodomys mandarinus. The ancestral sex chromosomes have been replaced by 4 neo-sex chromosomes. These sex chromosomes show non-Mendelian inheritance and epistatic sex determination, as well as unaccounted-for karyotype frequencies. I suggest a model to account for the complex observed inheritance patterns. The proposed model combines putative adaptations previously observed in rodents, including feminizing X chromosomes and Y-biased spermatogenesis, with a novel proposed mechanism of genomic imprinting of X-linked genes during oogenesis in XY females. Alternative possibilities are also discussed. The proposed scenario provides a relatively simple and testable model for the function and origins of a remarkably complex mammalian sex chromosomal system.