DNA charge transport as a first step in coordinating the detection of lesions by repair proteins

Damaged bases in DNA are known to lead to errors in replication and transcription, compromising the integrity of the genome. We have proposed a model where repair proteins containing redox-active [4Fe-4S] clusters utilize DNA charge transport (CT) as a first step in finding lesions. In this model, the population of sites to search is reduced by a localization of protein in the vicinity of lesions. Here, we examine this model using single-molecule atomic force microscopy (AFM). XPD, a 5′-3′ helicase involved in nucleotide excision repair, contains a [4Fe-4S] cluster and exhibits a DNA-bound redox potential that is physiologically relevant. In AFM studies, we observe the redistribution of XPD onto kilobase DNA strands containing a single base mismatch, which is not a specific substrate for XPD but, like a lesion, inhibits CT. We further provide evidence for DNA-mediated signaling between XPD and Endonuclease III (EndoIII), a base excision repair glycosylase that also contains a [4Fe-4S] cluster. When XPD and EndoIII are mixed together, they coordinate in relocalizing onto the mismatched strand. However, when a CT-deficient mutant of either repair protein is combined with the CT-proficient repair partner, no relocalization occurs. These data not only indicate a general link between the ability of a repair protein to carry out DNA CT and its ability to redistribute onto DNA strands near lesions but also provide evidence for coordinated DNA CT between different repair proteins in their search for damage in the genome

Genetic mapping, synteny, and physical location of two loci for Fusarium oxysporum f. sp. tracheiphilum race 4 resistance in cowpea [Vignaunguiculata (L.) Walp].

Fusarium wilt is a vascular disease caused by the fungus Fusariumoxysporum f.sp. tracheiphilum (Fot) in cowpea [Vignaunguiculata (L.) Walp]. In this study, we mapped loci conferring resistance to Fot race 4 in three cowpea RIL populations: IT93K-503-1 × CB46, CB27 × 24-125B-1, and CB27 × IT82E-18/Big Buff. Two independent loci which confer resistance to Fot race 4 were identified, Fot4-1 and Fot4-2. Fot4-1 was identified in the IT93K-503-1 (resistant) × CB46 (susceptible) population and was positioned on the cowpea consensus genetic map, spanning 21.57-29.40 cM on linkage group 5. The Fot4-2 locus was validated by identifying it in both the CB27 (resistant) × 24-125B-1 (susceptible) and CB27 (resistant) × IT82E-18/Big Buff (susceptible) populations. Fot4-2 was positioned on the cowpea consensus genetic map on linkage group 3; the minimum distance spanned 71.52-71.75 cM whereas the maximum distance spanned 64.44-80.23 cM. These genomic locations of Fot4-1 and Fot4-2 on the cowpea consensus genetic map, relative to Fot3-1 which was previously identified as the locus conferring resistance to Fot race 3, established that all three loci were independent. The Fot4-1 and Fot4-2 syntenic loci were examined in Glycine max, where several disease-resistance candidate genes were identified for both loci. In addition, Fot4-1 and Fot4-2 were coarsely positioned on the cowpea physical map. Fot4-1 and Fot4-2 will contribute to molecular marker development for future use in marker-assisted selection, thereby expediting introgression of Fot race 4 resistance into future cowpea cultivars

The Lopsidedness of Present-Day Galaxies: Results from the Sloan Digital Sky Survey

Large-scale asymmetries in the stellar mass distribution in galaxies are believed to trace non-equilibrium situations in the luminous and/or dark matter component. These may arise in the aftermath of events like mergers, accretion, and tidal interactions. These events are key in the evolution of galaxies. In this paper we quantify the large-scale lopsidedness of light distributions in 25155 galaxies at z < 0.06 from the Sloan Digital Sky Survey Data Release 4 using the m = 1 azimuthal Fourier mode. We show that the lopsided distribution of light is primarily due to a corresponding lopsidedness in the stellar mass distribution. Observational effects, such as seeing, Poisson noise, and inclination, introduce only small errors in lopsidedness for the majority of this sample. We find that lopsidedness correlates strongly with other basic galaxy structural parameters: galaxies with low concentration, stellar mass, and stellar surface mass density tend to be lopsided, while galaxies with high concentration, mass, and density are not. We find that the strongest and most fundamental relationship between lopsidedness and the other structural parameters is with the surface mass density. We also find, in agreement with previous studies, that lopsidedness tends to increase with radius. Both these results may be understood as a consequence of several factors. The outer regions of galaxies and low-density galaxies are more susceptible to tidal perturbations, and they also have longer dynamical times (so lopsidedness will last longer). They are also more likely to be affected by any underlying asymmetries in the dark matter halo.Comment: 42 pages, 13 figures, 3 tables, accepted to Ap

Les conséquences développementales de la maltraitance des filles

Objet : L’étude traite des conséquences des mauvais traitements, corroborés par des instances officielles, sur le comportement antisocial et sur d’autres indicateurs connexes chez les femmes d’un échantillon longitudinal et représentatif de la ville de Rochester aux États-Unis.Méthodologie : Les données proviennent de l’étude de Rochester sur le développement des jeunes, une étude de cohortes portant sur l’apparition de problèmes comportementaux à partir d’un échantillon de 1 000 jeunes suivis de l’âge de 13 ans jusqu’à l’âge adulte. Les analyses se concentrent uniquement sur les 271 adolescentes d’origine afro-américaine ou hispanique de l’échantillon. La consultation des registres du Service de protection de l’enfance du comté a permis de découvrir 74 (27 %) filles ayant subi des mauvais traitements. Les conséquences qui seront analysées sont les arrestations, la délinquance et la violence autorapportées, la consommation de drogues, les problèmes liés à la consommation d’alcool, la violence subie et manifestée dans les relations de couple, les symptômes dépressifs et les risques de contracter des maladies transmises sexuellement (MTS) et le SIDA au début de l’âge adulte (20-22 ans).Résultats : Les analyses bivariées indiquent que la maltraitance est associée à plusieurs conséquences négatives au début de l’âge adulte. La régression logistique, qui contrôle les variables sociodémographiques et la délinquance juvénile, confirme que la maltraitance augmente les risques d’apparition de plusieurs conséquences négatives. Les résultats suggèrent également que l’abus sexuel peut avoir des répercussions particulièrement graves chez les jeunes femmes.Implications : La présente recherche vise l’amélioration des programmes de prévention et de traitement pour les jeunes femmes ayant été abusées et négligées au cours de l’enfance.Purpose: The current study investigates the impact of substantiated maltreatment on antisocial behavior and other outcomes among young adult women in a representative community sample followed longitudinally.Methods: Data come from the Rochester Youth Development Study (RYDS), a cohort study of the development of problem behaviors in a sample of 1,000 urban youth followed from age 13 into adulthood. Subjects include 68% African American, 17% Hispanic, and 15% White youth. This analysis focuses only on the 271 young women in the panel. County Child Protective Service records were searched and 74 (27%) of the young women experienced substantiated maltreatment. Outcomes include arrest, self-reported general and violent offending, drug use, problem alcohol use, partner violence perpetration and victimization, depressive symptoms, and STD/HIV risk in early adulthood (ages 20-22).Results: We find that experiencing substantiated maltreatment increases the risk of most outcomes at the bivariate level. Employing logistic regression, maltreatment increases the odds of several negative consequences after controlling for confounding sociodemographic variables including poverty, family structure, parental education, race/ethnicity, and adolescent delinquency. Results also suggest that sex abuse may be particularly problematic for these young women in emerging adulthood.Implications: We discuss implications for understanding pathways and processes, and for improving prevention and treatment for abused and neglected young women

ATP-Stimulated, DNA-Mediated Redox Signaling by XPD, a DNA Repair and Transcription Helicase

Using DNA-modified electrodes, we show DNA-mediated signaling by XPD, a helicase that contains a [4Fe-4S] cluster and is critical for nucleotide excision repair and transcription. The DNA-mediated redox signal resembles that of base excision repair proteins, with a DNA-bound redox potential of ~80 mV versus NHE. Significantly, this signal increases with ATP hydrolysis. Moreover, the redox signal is substrate-dependent, reports on the DNA conformational changes associated with enzymatic function, and may reflect a general biological role for DNA charge transport

Phase Transitions of Orientifold Gauge Theories at Large N in Finite Volume

In this paper we consider the phase structure of ``orientifold'' gauge theories--obtained from unitary supersymmetric gauge theories by replacing adjoint Majorana fermions by Dirac fermions in the symmetric or anti-symmetric representations--in finite volume S^3 x S^1. If the radius of the S^3 is small the calculations can be performed at weak coupling for any value of the S^1 radius. We demonstrate that there is a confinement/de-confining type of phase transition even when the fermions have periodic (non-thermal) boundary conditions around S^1. At small radius of S^1, the theory is in a phase where charge conjugation and large non-periodic gauge transformation are spontaneously broken. But for large radius of S^1 the phase preseves these symmetries just as in the related supersymmetric theory.Comment: 12 page

Conduction band tight-binding description for silicon applied to phosphorous donors

A tight-binding parametrization for silicon, optimized to correctly reproduce effective masses as well as the reciprocal space positions of the conduction-band minima, is presented. The reliability of the proposed parametrization is assessed by performing systematic comparisons between the descriptions of donor impurities in Si using this parametrization and previously reported ones. The spectral decomposition of the donor wavefunction demonstrates the importance of incorporating full band effects for a reliable representation, and that an incomplete real space description results from a truncated reciprocal space expansion as proposed within the effective mass theory.Comment: 4 pages, 3 figure

Comparative Morphological and Anatomical Studies on the Leaf and Stem of some Medicinal Plants: Jatropha curcas L. and Jatropha tanjorensis J.L. Ellis and Saroja (Euphorbiaceae)

Morphological and anatomical investigations were carried out on two species of Jatropha: J. curcas and J. tanjorensis. These studies were carried out on the leaf and stem of these plants using the light microscope fitted with a Nikkon digital camera. Trichomes were observed in the leaf section of J. tanjorensis whereas these were lacking in J. curcas. The lower palisade parenchyma of J. tanjorensis consists of fewer layers but is thicker compared to that of J. curcas, which possessed more but thinner palisade layer

JOB STRESS AND EMPLOYEES' PERSONAL FULFILLMENTS IN NIGERIAN BANKING ORGANISATIONS

In this modern world, stress has become a global phenomenon that occurs in a variety of ways in every organization, irrespective of the profession. In today’s work life, employees are generally working longer hours as the rising levels of responsibilities require them to exert themselves even more strenuously to meet targets and raise expectations about their work performance. Banking is an inherently stressful profession characterized by long working hours, serious competition, ethical dilemmas, regulatory bottlenecks, and dealing with a diverse customer base.Hence, the thrust of this paper is to examine the effects of job stress on employees' personal fulfilments in Nigerian banking organizations, with the objectives of identifying the drivers of job stress and examining the coping strategies to managing job stress to enhance employees’ personal fulfilments. While adopting Two-Factor Theory of Job Satisfaction and the Person-Environment Fit Theory, a secondary method of data collection was utilized, in which books, journals, and internet-based&nbsp;articles were reviewed and their content analyzed. Based on the literature reviewed, the paper showed that inadequate resources to do the job, high demands, workload, time pressures, lack of job security, understaffing, technological revolution, role ambiguity, and role conflict, among others, were the major causes of job stress affecting bank employees. The paper also showed that headaches, eating disorders, sleep disturbances, fatigue, muscle aches and pains, anxiety, irritability, low morale, depression, alcohol and drug use, feeling powerless and isolation from family, friends, and co-workers, among others, were the major effects of job stress on the employees personal fulfilments in the Nigerian banking organizations. Based on these findings, it was concluded and recommended that managers should invite employees who think that they are being given jobs that are in contradiction with their skills and clarify their roles. They should facilitate an employee skill audit that will help to place employees that feel underutilized. Management should introduce stress management techniques into banking organizations. An Employee Assistance Program should be introduced for early identification and intervention of problems capable of causing stress e.t.c