bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parental Effect of DNA (Cytosine-5) Methyltransferase 1 on Grandparental-Origin-Dependent Transmission Ratio Distortion in Mouse Crosses and Human Families
Authors: Yang Lanjian , Andrade Moises Freitas , Labialle Stephane , Moussette Sanny , Geneau Geneviève , Sinnett Donna , Belisle Alexandre , Greenwood Celia M T , Naumova Anna K 
Published: January 2008

Abstract
Transmission ratio distortion (TRD) is a deviation from the expected Mendelian 1:1 ratio of alleles transmitted from parents to offspring and may arise by different mechanisms. Earlier we described a grandparental-origin-dependent sex-of-offspring-specific TRD of maternal chromosome 12 alleles closely linked to an imprinted region and hypothesized that it resulted from imprint resetting errors in the maternal germline. Here, we report that the genotype of the parents for loss-of-function mutations in the Dnmt1 gene influences the transmission of grandparental chromosome 12 alleles. More specifically, maternal Dnmt1 mutations restore Mendelian transmission ratios of chromosome 12 alleles. Transmission of maternal alleles depends upon the presence of the Dnmt1 mutation in the mother rather than upon the Dnmt1 genotype of the offspring. Paternal transmission mirrors the maternal one: live-born offspring of wild-type fathers display 1:1 transmission ratios, whereas offspring of heterozygous Dnmt1 mutant fathers tend to inherit grandpaternal alleles. Analysis of allelic transmission in the homologous region of human chromosome 14q32 detected preferential transmission of alleles from the paternal grandfather to grandsons. Thus, parental Dnmt1 is a modifier of transmission of alleles at an unlinked chromosomal region and perhaps has a role in the genesis of TRD.
Genetic Linkage Map of the Nucleolus Organizer Region in the Soybean
Authors: Yang Kiwoung , Jeong Soon-Chun 
Published: January 2008

Abstract
Simple polymorphisms in ribosomal DNA repeats in the nucleolus organizer region (NOR) permitted the development of markers for the genetic mapping of the soybean NOR. The markers map to the top end of soybean linkage group F, one of either telomeric end predicted in the cytogenetic and primary trisomic studies.
A Gain-of-Function Suppressor Screen for Genes Involved in Dorsal–Ventral Boundary Formation in the Drosophila Wing
Authors: Bejarano Fernando , Luque Carlos M , Herranz Héctor , Sorrosal Georgina , Rafel Neus , Pham Thu Thuy , Milán Marco 
Published: January 2008

Abstract
The Drosophila wing primordium is subdivided into a dorsal (D) and a ventral (V) compartment by the activity of the LIM-homeodomain protein Apterous in D cells. Cell interactions between D and V cells induce the activation of Notch at the DV boundary. Notch is required for the maintenance of the compartment boundary and the growth of the wing primordium. Beadex, a gain-of-function allele of dLMO, results in increased levels of dLMO protein, which interferes with the activity of Apterous and results in defects in DV axis formation. We performed a gain-of-function enhancer-promoter (EP) screen to search for suppressors of Beadex when overexpressed in D cells. We identified 53 lines corresponding to 35 genes. Loci encoding for micro-RNAs and proteins involved in chromatin organization, transcriptional control, and vesicle trafficking were characterized in the context of dLMO activity and DV boundary formation. Our results indicate that a gain-of-function genetic screen in a sensitized background, as opposed to classical loss-of-function-based screenings, is a very efficient way to identify redundant genes involved in a developmental process.
An Unstable Targeted Allele of the Mouse Mitf Gene With a High Somatic and Germline Reversion Rate
Authors: Bismuth Keren , Skuntz Susan , Hallsson Jón H , Pak Evgenia , Dutra Amalia S , Steingrímsson Eiríkur , Arnheiter Heinz 
Published: January 2008

Abstract
The mouse Mitf gene encodes a transcription factor that is regulated by serine phosphorylation and is critical for the development of melanin-containing pigment cells. To test the role of phosphorylation at a particular serine, S73 in exon 2 of Mitf, we used a standard targeting strategy in mouse embryonic stem cells to change the corresponding codon into one encoding an alanine. By chance, we generated an allele in which 85,222 bp of wild-type Mitf sequence are duplicated and inserted into an otherwise correctly targeted Mitf gene. Depending on the presence or absence of a neomycin resistance cassette, this genomic rearrangement leads to animals with a white coat with or without pigmented spots or a gray coat with obligatory white and black spots. Several independent, genetically stable germline revertants that lacked the duplicated wild-type sequence but retained the targeted codon were then derived. These animals were normally pigmented, indicating that the serine-to-alanine mutation is not deleterious to melanocyte development. The fact that mosaic coat reversions occur in all mice lacking the neo-cassette and that ∼1% of these transmit a reverted allele to their offspring places this mutation among those with the highest spontaneous reversion rates in mammals.
Spatial and Temporal Control of Gene Expression in Drosophila Using the Inducible GeneSwitch GAL4 System. I. Screen for Larval Nervous System Drivers
Authors: Nicholson Louise , Singh Gunisha K , Osterwalder Thomas , Roman Gregg W , Davis Ronald L , Keshishian Haig 
Published: January 2008

Abstract
There is a critical need for genetic methods for the inducible expression of transgenes in specific cells during development. A promising approach for this is the GeneSwitch GAL4 system of Drosophila. With GeneSwitch GAL4 the expression of upstream activating sequence (UAS) effector lines is controlled by a chimeric GAL4 protein that becomes active in the presence of the steroid RU486 (mifepristone). To improve the utility of this expression system, we performed a large-scale enhancer-trap screen for insertions that yielded nervous system expression. A total of 204 GeneSwitch GAL4 lines with various larval expression patterns in neurons, glia, and/or muscle fibers were identified for chromosomes I–III. All of the retained lines show increased activity when induced with RU486. Many of the lines reveal novel patterns of sensory neurons, interneurons, and glia. There were some tissue-specific differences in background expression, with muscles and glia being more likely to show activity in the absence of the inducing agent. However, &gt;90% of the neuron-specific driver lines showed little or no background activity, making them particularly useful for inducible expression studies.
Role of the Saccharomyces cerevisiae Rad51 Paralogs in Sister Chromatid Recombination
Authors: Mozlin Amy M , Fung Cindy W , Symington Lorraine S 
Published: January 2008

Abstract
Rad51 requires a number of other proteins, including the Rad51 paralogs, for efficient recombination in vivo. Current evidence suggests that the yeast Rad51 paralogs, Rad55 and Rad57, are important in formation or stabilization of the Rad51 nucleoprotein filament. To gain further insights into the function of the Rad51 paralogs, reporters were designed to measure spontaneous or double-strand break (DSB)-induced sister or nonsister recombination. Spontaneous sister chromatid recombination (SCR) was reduced 6000-fold in the rad57 mutant, significantly more than in the rad51 mutant. Although the DSB-induced recombination defect of rad57 was suppressed by overexpression of Rad51, elevated temperature, or expression of both mating-type alleles, the rad57 defect in spontaneous SCR was not strongly suppressed by these same factors. In addition, the UV sensitivity of the rad57 mutant was not strongly suppressed by MAT heterozygosity, even though Rad51 foci were restored under these conditions. This lack of suppression suggests that Rad55 and Rad57 have different roles in the recombinational repair of stalled replication forks compared with DSB repair. Furthermore, these data suggest that most spontaneous SCR initiates from single-stranded gaps formed at stalled replication forks rather than DSBs.
Examination of Interchromosomal Interactions in Vegetatively Growing DiploidSchizosaccharomyces pombeCells by Cre/loxP Site-Specific Recombination
Authors: Molnar Monika , Kleckner Nancy 
Published: January 2008

AbstractThe probability with which different regions of a genome come in contact with one another is a question of general interest. The current study addresses this subject for vegetatively growing diploid cells of fission yeast Schizosaccharomyces pombe by application of the Cre/loxP site-specific recombination assay. High levels of allelic interactions imply a tendency for chromosomes to be colocalized along their lengths. Significant homology-dependent pairing at telomere proximal loci and robust nonspecific clustering of centromeres appear to be the primary determinants of this feature. Preference for direct homolog-directed interactions at interstitial chromosomal regions was ambiguous, perhaps as a consequence of chromosome flexibility and the constraints and dynamic nature of the nucleus. Additional features of the data provide evidence for chromosome territories and reveal an intriguing phenomenon in which interaction frequencies are favored for nonhomologous loci that are located at corresponding relative (rather than absolute) positions within their respective chromosome arms. The latter feature, and others, can be understood as manifestations of transient, variable, and/or occasional nonspecific telomeric associations. We discuss the factors whose interplay sets the probabilities of chromosomal interactions in this organism and implications of the inferred organization for ectopic recombination.
Distinct Activities of the Germline and Somatic Reproductive Tissues in the Regulation of Caenorhabditis elegans' Longevity
Authors: Yamawaki Tracy M , Arantes-Oliveira Nuno , Berman Jennifer R , Zhang Peichuan , Kenyon Cynthia 
Published: January 2008

Abstract
The two parts of the Caenorhabditis elegans reproductive system, the germ cells and the somatic reproductive tissues, each influence the life span of the animal. Removing the germ cells increases longevity, and this life span extension requires the somatic gonad. Here we show that the somatic gonad and the germ cells make distinct contributions to life span determination. The life span increase produced by loss of the germ cells requires the DAF-16/FOXO transcription factor. In response to germ-cell removal, DAF-16 accumulates in nuclei. We find that the somatic gonad is not required for DAF-16 nuclear accumulation or for the increased stress resistance that is produced by germ-cell removal. The somatic gonad is required, however, for expression of specific DAF-16 target genes. DAF-16 is known to be activated by reduced insulin/IGF-1 signaling in C. elegans. In certain insulin/IGF-1-pathway mutants, the somatic gonad is not required for germ-cell removal to extend life span. Our genetic experiments suggest that these mutations reduce insulin/IGF-1 signaling below a critical threshold level. At these low levels of insulin/IGF-1 signaling, factors normally provided by the somatic gonad are no longer needed for germ-cell removal to increase the expression of DAF-16 target genes.
Differential Regulation of Anaphase Promoting Complex/Cyclosome Substrates by the Spindle Assembly Checkpoint in Saccharomyces cerevisiae
Authors: Keyes Brice E , Yellman Christopher M , Burke Daniel J 
Published: January 2008

Abstract
The anaphase promoting complex (APC) targets proteins for degradation to promote progression through the cell cycle. Here we show that Clb5, an APCCdc20 substrate, is degraded when the spindle checkpoint is active, while other APCCdc20 substrates are stabilized, suggesting that APCCdc20 inhibition by the spindle checkpoint is substrate specific.
Reproductive Characteristics of Weakfish in Delaware Bay: Implications for Management
Authors: Nye Janet A. , Targett Timothy E. , Helser Thomas E. 
Published: January 2008

Abstract
We quantified size and age at maturity, batch fecundity, spawning frequency, and annual fecundity for weakfish Cynoscion regalis in Delaware Bay in 1999 and 2000. Information about these critical characteristics are needed for stock assessment models, which have never been assessed in Delaware Bay nor anywhere in the range of the weakfish since 1991–1992, when abundance was very low. Stock size increased from 1991–1992 to 1999–2000, but size at maturity was 168 ± 4.1 mm (mean ± SE) and did not appear to increase with stock size. Ninety-seven percent of age-1 fish were mature, but they arrived later to the estuary, had lower batch fecundity, and spawned less frequently than did older fish. The annual fecundity of fish age 2–6 was at least 30 times as great as that of age-1 fish. Batch fecundity was similar between Chesapeake Bay and Delaware Bay in the same year once corrected for fish size. The relationships of batch fecundity to both female weight and length were statistically equal between the two time periods in which batch fecundity has been quantified (1991–1992 and 1999–2000). However, we did detect differences in batch fecundity at age and the length–weight relationship over time. The difference in the length–weight relationship is due to the absence of large (&gt;400 mm) and old (&gt;4 years) females and indicates that the population has not recovered to its former stock structure. The absence of large females could lead to lower egg production than expected and may help explain the slow recovery of this species. We suggest decreasing the proportion of mature fish at age 1 to account for the low egg production of this age-class and to continue efforts to enhance the size and age structure of the population.
Retrospective Evaluation of Preseason Forecasting Models for Sockeye and Chum Salmon
Authors: Haeseker Steven L. , Peterman Randall M. , Su Zhenming , Wood Chris C. 
Published: January 2008

Abstract
Using comprehensive data sets for chum salmon Oncorhynchus keta (40 stocks) and sockeye salmon O. nerka (37 stocks) throughout their North American ranges, we compared the retrospective performance of 11 models in preseason forecasting of adult abundance. Chum and sockeye salmon have more complicated age structures than pink salmon O. gorbuscha, which we investigated previously (Haeseker et al. 2005), and this complexity presents new challenges as well as opportunities for forecasting. We extended our previous work to include two new forecasting models that make use of leading indicators: either the survival rate of earlier-maturing pink salmon from the same brood year (Ricker pink salmon index model) or the abundance of earlier-maturing siblings (hybrid sibling model, a new version of the standard sibling model). No single forecasting model was consistently the best for either chum or sockeye salmon, but the hybrid sibling model frequently performed best based on mean absolute error, mean percent error, and root mean square error. As was observed for pink salmon, several naïve models (i.e., simple time series models without explicitly modeled mechanisms) also performed well, as did forecast averaging models composed of two models with the least-correlated forecasting errors. In general, model ranking depended on the particular stock and performance measure used. However, even the top-ranked model for each stock explained on average only 21% of the observed interannual variation in chum salmon recruitment and only 36% of the variation in sockeye salmon recruitment. Although improvements may be possible for some stocks in specific circumstances, a major breakthrough in general forecasting ability seems unlikely given the breadth of stocks and models examined to date. Therefore, better in-season updates and adjustments to fishing regulations and a cautious approach to opening and closing fisheries should remain high priorities.
Influence of River Level on Temperature and Hydraulic Gradients in Chum and Fall Chinook Salmon Spawning Areas Downstream of Bonneville Dam, Columbia River
Authors: Geist David R. , Arntzen Evan V. , Murray Christopher J. , McGrath Kathleen E. , Bott Yi-Ju , Hanrahan Timothy P. 
Published: January 2008

Abstract
Chum salmon Oncorhynchus keta and fall Chinook salmon O. tshawytscha segregate spatially during spawning in the Ives Island side channel of the lower Columbia River downstream from Bonneville Dam. Previous research during one spawning season (2000) suggested that these species selected spawning habitats based on differences in hyporheic temperature and vertical hydraulic gradient (VHG). In this study we confirmed the spatial segregation of spawning based on hyporheic characteristics over 4 years (2001–2004) and examined the effects of load-following operations (power generation to meet short-term electrical demand) at Bonneville Dam on hyporheic function and characteristics. We found that during the study period hyporheic temperature and VHG in chum salmon spawning areas were highly variable during periods of load-following operation, when river levels fluctuated. In contrast, hyporheic water temperature and VHG within chum salmon spawning areas fluctuated less when river levels were not changing owing to load-following operation. Variable temperature and VHG could affect chum and fall Chinook salmon spawning segregation and incubation success by altering the cues each species uses to select redd sites. Additional research will be required to fully assess the effects of load-following operations on the hyporheic environment, spawning site selection, and incubation success of chum and fall Chinook salmon downstream from Bonneville Dam.
Indirect determination of lutetium by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode
Authors: Kumrić Ksenija , Trtić-Petrović Tatjana , Ignjatović Ljubiša , Čomor Jožef 
Published: January 2008

Abstract
Lutetium has been determined by differential pulse anodic stripping voltammetry in an acidic solution containing Zn-EDTA. Lutetium (III) ions liberated zinc (II), which was preconcentrated on a hanging mercury drop electrode and stripped anodically, resulting in peak current linearly dependent on lutetium (III) concentration. Less than 0.4 ng mL−1 lutetium could be detected after a 2 min deposition.
Synthesis, characterization and spectroscopic properties of some new phenylazo-6-aminouracil
Authors: Seferoğlu Zeynel , Ertan Nermin 
Published: January 2008

Abstract
In this study, a series of new 5-phenylazo-6-aminouracil dyes were prepared by linking m-,p-nitroaniline, m-,p-chloroaniline, m-,p-anisidine, m-,p-toluidine, m-,p-cyanoaniline, p-ethoxyaniline, p-phenoxyaniline, p-ethylaniline, p-acetamidoaniline, p-acetylaniline, p-carboxyaniline and aniline to 6-aminouracil. The prepared dyes were characterized by UV-vis, FT-IR, 1H NMR spectroscopic techniques and elemental analysis. The effect of acid and base upon the UV-vis spectra of these dyes were investigated. In addition, the solvatochromic behaviors and substituent effects in various solvents were evaluated.
Synthesis and characterization of thermoresponsive hydrogels cross-linked with chitosan
Authors: Yu Yueqin , Chang Xianzhi , Ning Hansheng , Zhang Shusheng 
Published: January 2008

Abstract
Hydrogels composed of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) were prepared by redox polymerization with degradable chitosan cross-linkers. Chitosan degradable cross-linkers were synthesized by the acrylation of the amine groups of glucosamine units within chitosan and characterized with 1H NMR. With the chitosan cross-linkers, loosely cross-linked poly(N-isopropylacryamideco-acrylic acid) [P(NIPAAm-co-AAc)] hydrogels were prepared, and their phase transition behavior, lower critical solution temperature (LCST), water content and degradation properties were investigated. The chitosan cross-linked P(NIPAAm-co-AAc) hydrogels were pliable and transparent at room temperature. The LCST could be adjusted at 32∼39°C by alternating the feed ratio. Swelling was influenced by NIPAAm/AAc monomer ratio, cross-linking density, swelling media, and temperature. All hydrogels with different feeding ratios contained more than 95% water at 25°C in the ultra pure water and phosphate-buffered saline (PBS, pH = 7.4 ± 0.1), and had a prospective swelling in the simulated gastric fluids (SGF, pH = 1.2) &gt; 72.54%. In degradation studies, breakdown of the chitosan cross-linked P(NIPAAm-co-AAc) hydrogels was dependent on the cross-linking density. The chitosan cross-linked P(NIPAAm-co-AAc) hydrogels which can be tailored to create environmentally-responsive artificial extracellular materials have great potential for future use.
Watson-crick base pairs with thiocarbonyl groups: How sulfur changes the hydrogen bonds in DNA
Authors: Guerra Célia , Baerends Evert , Bickelhaupt F. 
Published: January 2008

Abstract
We have theoretically analyzed mimics of Watson-Crick AT and GC base pairs in which N-H···O hydrogen bonds are replaced by N-H···S, using the generalized gradient approximation (GGA) of density functional theory at BP86/TZ2P level. The general effect of the above substitutions is an elongation and a slight weakening of the hydrogen bonds that hold together the base pairs. However, the precise effects depend on how many, and in particular, on which hydrogen bonds AT and GC are substituted.. Another purpose of this work is to clarify the relative importance of electrostatic attraction versus orbital interaction in the hydrogen bonds involved in the mimics, using a quantitative bond energy decomposition scheme. At variance with widespread believe, the orbital interaction component in these hydrogen bonds is found to contribute more than 40% of the attractive interactions and is thus of the same order of magnitude as the electrostatic component, which provides the remaining attraction.
Investigation on the catalytic activity of doped low-percentage oxide catalysts Mn/ZnO obtained from oxalate precursor
Authors: Donkova Borjana , Milenova Katja , Mehandjiev Dimitar 
Published: January 2008

Abstract
The precursors with a low manganese content ≤ 0.07% Mn were synthesized by spontaneous crystallization from Zn2+, Mn2+ and C2O42−-containing solutions. The initial ratio Zn2+:C2O42− = 1:1 and 1:2 influences the morphology and prevailing orientations of the crystallites in the oxalate samples. The presence of such small Mn content in the samples does not change the morphology or size of the crystals. The ZnO and Mn/ZnO oxides with manganese content from 0.51×10−2 to 15.1×10−2 Wt % are obtained after thermal decomposition of the oxalates. The oxides preserved the morphology of the precursors. The catalytic tests show that the pure ZnO has a poor activity for CO oxidation reaction. Its doping with Mn promotes the catalytic activity (up from twice to five times) in spite of the very low contents of the dopants. The observed increase of the activity depends on both dopant concentration and Zn2+:C2O42− ratio, probably due to the different mechanism of the manganese inclusion and different morphology of the oxides. The catalysts of the 1:2 series are more active in CO oxidation reaction.
Was that a man? Sex identification as a function of menstrual cycle and masculinity
Authors: Johnston Lucy , Miles Lynden , Macrae C. Neil 
Published: January 2008

AbstractThe accuracy of female perceivers on a face sex‐categorization task was investigated as a function of perceivers' menstrual cycle and target facial qualities. Regularly ovulating female participants completed a sex‐categorization task twice, once during ovulation (high fertility) and once during menstruation (low fertility). Perceivers made more errors in identifying male than female faces at both testing sessions. Fewer errors were made in identifying male targets rated high on masculinity, but only during periods of high fertility. For female targets accuracy was negatively associated with masculinity and positively associated with attractiveness ratings, at both high and low fertility testing sessions. Results are discussed in terms of adaptive person construal. Copyright © 2008 John Wiley & Sons, Ltd.