Nuclear Surveillance and Degradation of Hypomodified Initiator tRNA\u3csup\u3eMet\u3c/sup\u3e in \u3cem\u3eS. cerevisiae\u3c/em\u3e

The tRNA m1A58 methyltransferase is composed of two subunits encoded by the essential genes TRM6 and TRM61 (formerly GCD10 and GCD14). The trm6-504 mutation results in a defective m1A methyltransferase (Mtase) and a temperature-sensitive growth phenotype that is attributable to the absence of m1A58 and consequential tRNAiMet instability. We used a genetic approach to identify the genes responsible for tRNAiMet degradation in trm6 cells. Three recessive extragenic mutations that suppress trm6-504 mutant phenotypes and restore hypomodified tRNAiMet to near normal levels were identified. The wild-type allele of one suppressor, DIS3/RRP44, encodes a 3′-5′ exoribonuclease and a member of the multisubunit exosome complex. We provide evidence that a functional nuclear exosome is required for the degradation of tRNAiMet lacking m1A58. A second suppressor gene encodes Trf4p, a DNA polymerase (pol σ) with poly(A) polymerase activity. Whereas deletion of TRF4 leads to stabilization of tRNAiMet, overexpression of Trf4p destabilizes the hypomodified tRNAiMet in trm6 cells. The hypomodified, but not wild-type, pre-tRNAiMet accumulates as a polyadenylated species, whose abundance and length distribution both increase upon Trf4p overexpression. These data indicate that a tRNA surveillance pathway exists in yeast that requires Trf4p and the exosome for polyadenylation and degradation of hypomodified pre-tRNAiMet

Employee Assistance and Drug Testing: Fairness and Injustice in the Workplace

Every few years, the mass media report that a drug epidemic is sweeping America and sapping its economy

Development of a New Polymerase Chain Reaction Assay for the Rapid Detection of the Oral Pathogenic Bacterium, Selenomonas Noxia

Background In recent studies, periodontal health has been linked to being overweight and/or obese. Among common oral bacteria, Selenomonas noxia has been implicated in converting periodontal health to disease, and Selenomonas species have also been found in gastric ulcers. The objective of this study was to develop and validate a quantitative polymerase chain reaction (qPCR) assay for the specific and rapid detection of S. noxia. Methods Two oligonucleotide primer pairs and one probe were designed and tested to determine optimal amplification signal with three strains of S. noxia. The PCR assay was tested against fourteen non-target organisms, including closely related oral Selenomonads, one phylogenetically closely related bacterium, and two commonly isolated oral bacteria. Results One of the primer sets was more sensitive at detecting the target organism and was selected for optimization and validation experiments. The designed primers and probe amplified the target organism with 100 % specificity. PCR inhibition was observed with an internal positive control, and inhibition was resolved by diluting the DNA extract. Conclusions The qPCR assay designed in this study can be used to specifically detect S. noxiain the clinical setting and in future research involving the enhanced detection of S. noxia. The assay can also be used in epidemiological studies for understanding the role of S. noxia in disease processes including, but not limited to, oral health and obesity of infectious origin

Role of Rare-Earth Oxide Additives on Mechanical Properties and Oxidation Behavior of Si 3 N 4 /BN Fibrous Monolith Ceramics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65415/1/j.1551-2916.2006.00911.x.pd

Care For Pastors: Learning From Clergy and Their Spouses

Pastors and their spouses face unique challenges because of the nature of pastoral work, and yet most manage these challenges successfully. Five studies are presented which help distinguish between intrapersonal, family, and community forms of care. Pastors rely heavily on intrapersonal forms of coping such as spiritual devotion, hobbies, exercise, and taking time away from work. The marriage relationship is also quite important for most clergy and spouses. Relationships outside the immediate family are not commonly identified as coping resources. Implications are discussed

Multipole Strength Distributions in 16-O Above the Dipole Resonance Region

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Understanding Video Game Developers as an Occupational Community

The video game industry has rapidly expanded over the last four decades; yet there is limited research about the workers who make video games. In examining these workers, this article responds to calls for renewed attention to the role of the occupation in understanding project-based workers in boundaryless careers. Specifically, this article uses secondary analysis of online sources to demonstrate that video game developers can be understood as a unique social group called an occupational community (OC). Once this classification has been made, the concept of OC can be used in future research to understand video game workers in terms of identity formation, competency development, career advancement and support, collective action, as well as adherence to and deviance from organizational and industry norms

Learned helplessness in chess players: The importance of task similarity and the role of skill

The effects of noncontingency between subjects' responses and outcomes were examined with respect to treatment/posttest similarity and skill in the task. The experimental design consisted of three groups. The first group had to solve chess problems with objective solutions and received veridical feedback; each member of the second group faced problems with no objective solutions, and received the same feedback as the member of the first group he was yoked with, but without any control on it; the control group received a waiting task. It was found that the group with unsolvable problems was more depressed than the two other groups at the end of the experiment. The mid-strength players were the most sensitive to the manipulation, and the weakest players showed little effect of learned helplessness. It was also found that the effects were proportional to the degree of similarity between the treatment and the posttest. The results limit the domain of applicability of the learned helplessness model

Naturally propped fractures caused by quartz cementation preserve oil reservoirs in basement rocks

MB is in receipt of a postgraduate studentship from PTDF (Nigeria). Skilled technical support was provided by M. Baron and J. Still. Two reviewers made valuable criticisms that improved the paper.Peer reviewedPostprin

Suspension high velocity oxy-fuel spraying of a rutile TiO 2 feedstock: microstructure, phase evolution and photocatalytic behaviour

Nano-structured TiO2 coatings were produced by suspension high velocity oxy fuel (SHVOF) thermal spraying using water-based suspensions containing 30 wt% of submicron rutile powders (~180 nm). By changing the flame heat powers from 40 kW to 101 kW, TiO2 coatings were obtained with distinctive microstructures, phases and photocatalytic behaviour. Spraying with low power (40 kW) resulted in a more porous microstructure with the presence of un-melted nano-particles and a lower content of the anatase phase; meanwhile, high powers (72/101 kW) resulted in denser coatings and rougher surfaces with distinctive humps but not necessarily with a higher content of anatase. Linear sweep voltammetry (LSV) was used to evaluate the photocatalytic performance. Surprisingly, coatings with the lowest anatase content (~20%) using 40 kW showed the best photocatalytic behaviour with the highest photo-conversion efficiency. It was suggested that this was partially owing to the increased specific surface area of the un-melted nano-particles. More importantly, the structural arrangement of the similarly sized TiO2 nano-crystallites between rutile and antase phases also created catalytic “hot spots” at the rutile−anatase interface and greatly improved the photo-activity