Parsing PARP: the enzymatic and biophysical characterization of poly (ADP-Ribose) polymerases I and II

Includes bibliographical references.2015 Summer.The ADP-ribosyl transferase (ART) family is a prominent group of at least seventeen enzymes comprised of mono (ADP-ribose) transferases (MARTs) and poly (ADP-ribose) polymerases (PARPs). Each family member contains a conserved PARP signature motif in the catalytic domain. Enzymatically active proteins, in the presence of co-factor NAD+, catalyze individual or multiple ADP-ribose groups onto themselves or other proteins in automodification and heteromodification, respectively. The act of ADP-ribosylation implicates the ART family in a multitude of cellular processes including, but not limited to, transcription, apoptosis, DNA damage, metabolism, and inflammation. The founding member of the ART family is PARP-1, a first responder to DNA damage and regulator of active gene expression. In its inactive state and as a chromatin architectural protein, PARP-1 tightly binds chromatin, thereby regulating cellular activities, signifying the importance of PARP-1 and chromatin interaction. Importantly, PARP-1 must be activated and automodified in order to bind histones and gain nucleosome assembly function. Structurally similar and in many ways thought to be functionally redundant, PARP-2 is also thought to primarily function in the DNA damage response. PARP-2 has a non-canonical DNA binding domain, and therefore it is able to recognize different types of DNA structures in comparison to PARP-1, which could suggest a unique role for PARP-2 in repair. PARP-2 has not been extensively studied in a chromatin or gene regulation context due to this assumed redundancy. Given the pronounced functional changes in PARP-1 upon automodification, it is important to better understand what exactly triggers its enzymatic activity. Similarly, due to the functional redundancy of PARP-2, insight into activators of its enzymatic activity could indicate specificity and selectivity for the protein. However, determining the details of nuclear components that activate PARP-1 and PARP-2 are limited by the availability of a reliable quantitative and kinetic assay, as well as by the availability of defined substrates. These limitations hinder the separation of potent, and thus biologically relevant, activators from weak or non-specific activators. Utilizing a fluorescence based enzyme assay adapted for this system, kinetic parameters of PARP-1 and PARP-2 allosteric activators are reported here. As proof of principle and to test the reliability of the enzymatic assay, PARP-1 and PARP-2 activity was first tested with nucleic acids and other previously reported activators, such as nucleosomes and histones. Next, potentially novel activators were tested. Notably, PARP-1 is activated in the presence of its enzymatic product, PAR, indicating a mechanism by which PARP-1 could spread at sites of DNA damage and active gene expression. PARP-2 exhibits unique activation and specificity different from that of PARP-1 through its enzymatic preference for RNA. Further, PARP-1 remains the prominent chromatin related PARP due to the weak interaction, both activity and affinity, of chromatin with PARP-2. However, while PARP-1 and PARP-2 can act individually, affinity and activity studies demonstrate a PARP-1 and PARP-2 complex suggesting that these proteins can act sequentially and simultaneously with one another during a PAR-mediated recruitment and signaling cascade. Overall, these data indicate novel functions and mechanisms for PARP-1 and PARP-2 within the nucleus as critical responders to DNA damage and gene regulation

B799: Field Appraisal of Resource Management Systems Farms Crop Yield and Quality Relationships with Soil Erosion

This document presents objectives and preliminary results of the Field Appraisal of Resource Management Systems (FARMS) study. This study assumes that estimates of soil erosion using the Universal Soil Loss Equation (USLE) represent long-term rather than short- term effects. The FARMS study randomly sampled 2400 plots over a three year period, 1980-82, for: crop management, soils, conservation practices and management, crop yields, soil chemistry, and sociological data. This report presents analyses from the 800 plots sampled in 1980. Statistics of rill and sheet soil erosion, as estimated by the Universal Soil Loss Equation (USLE), are presented. Data are presented for each of the factors in the USLE, for potato yields and quality, for yield of other field crops, and for soil nutrient analyses. A significant response of yield to erosion was found when the dataset was limited to the most commonly found soil, Caribou (144 plots). Data analyses including potato yields for all varieties and soils (429 plots) do not show any relation to predicted erosion. Regression analysis predicts that for each ton increase in soil erosion per acre per year up to 12 tons, a decrease of 2.3 hundred- weight of potatoes per acre will occur. The cover and management factor (C) was found to be the most important variable in the USLE in predicting potato yield decreases. With each increase of 0.1 C, the predicted yield decrease amounted to 17 hundredweight gross for potatoes, and 20 hundredweight decrease for US-1 potatoes per acre.https://digitalcommons.library.umaine.edu/aes_bulletin/1113/thumbnail.jp

Design data for brazed Rene 41 honeycomb sandwich

Strength data, creep data and residual strength data after cyclic thermal exposure were obtained at temperatures from 78 K to 1144 K (-320 F to 1600 F). The influences of face thickness, core depth, core gage, cell size and thermal/stress exposure conditions on the mechanical design properties were investigated. A braze alloy and process was developed that is adequate to fully develop the strength of the honeycomb core while simultaneously solution treating and aging the Rene 41 fact sheets. New test procedures and test specimen configurations were developed to avoid excessive thermal stresses during cyclic thermal exposure

B811: Field Appraisal of Resource Management Systems Farms Crop Yield and Quality Relationships with Soil Erosion - 1982

This document presents the objectives and third-year results of the Field Appraisal of Resource Management Systems (FARMS) study. The principal objectives of FARMS were to study the relationship of crop yields to predicted soil erosion and to simulate the economics of this relationship. Crop management, soils, conservation practices and management, crop yields, soil chemistry, and sociological data were collected. The data analyzed in preparing this report are from the 800 plots sampled in 1982. This report presents statistics for rill and sheet soil erosion, which is estimated by the Universal Soil Loss Equation (USLE) and assumed to represent a long term rather than short term effect. The report also presents summary statistics for each of the factors in the USLE: for potato yields and quality, for yields of four other field crops, and for soil nutrient analyses.https://digitalcommons.library.umaine.edu/aes_bulletin/1107/thumbnail.jp

B805: Field Appraisal of Resource Management Systems: Crop Yield and Quality Relationships with Soil Erosion—1981

This document presents objectives and results of the Field Appraisal of Resource Management Systems (FARMS) study\u27S second year. The principal objectives of FARMS were to study the relationship of crop yields to soil erosion and to simulate the economic nature of this relationship. Crop management, soils, conservation practices and management, crop yields, soil chemistry, and sociological data were collected from 800 plots in 1981. This report presents statistics for rill and sheet soil erosion, which are estimated by the Universal Soil Loss Equation (USLE) and assumed to represent a long-term rather than short-term effect. The report also presents summary statistics for each of the factors in the USLE: for potato yields and quality, for yields of six other field crops, and for soil nutrient analyses. No general response of potato yield and quality to predicted soil erosion was found. However, individual potato varieties responded differently to predicted soil erosion. Potato yields and specific gravity were found to be significantly related to the Cover and Management factor (C). Potato yield was found to decrease as intensity of potato production increased in the rotation period. Potato yields were significantly reduced when the previous crop was potatoes in comparison to grain or hay.https://digitalcommons.library.umaine.edu/aes_bulletin/1056/thumbnail.jp

Анализ механических состояний силовых систем. Сообщение 1. Предельное состояние

Изложены основы теории предельных состояний силовых систем, которые работают в условиях сложного нагружения (механическая усталость, трение и изнашивание, температура, электрохимическая коррозия). Получен энергетический критерий предельного состояния и описаны методы определения его параметров. Записаны условия прочности с учетом как циклической, так и контактной нагрузок.Викладено основи теорії граничних станів силових систем, що працюють в умовах складного навантаження (механічна утома, тертя та спрацьовування, температура, електрохімічна корозія). Отримано енергетичний критерій граничного стану та описано методи визначення його параметрів. Записано рівняння міцності з урахуванням як циклічного, так і контактного навантажень.Fundamentals of the theory of ultimate states in force systems operating under complex loading (mechanical fatigue, friction and wear, temperature, and electrochemical corrosion) have been described. Energy criterion of an ultimate state has been obtained and methods for calculating its parameters are given. Strength conditions taking into account both cyclic and contact loads are described

A comparison of calcium-activated potassium channel currents in cell- attached and excised patches

Single channel currents from Ca-activated K channels were recorded from cell-attached patches, which were then excised from 1321N1 human astrocytoma cells. Cells were depolarized with K (110 mM) so that the membrane potential was known in both patch configurations, and the Ca ionophore A23187 or ionomycin (20-100 microM) was used to equilibrate intracellular and extracellular [Ca] (0.3 or 1 microM). Measurements of intracellular [Ca] with the fluorescent Ca indicator quin2 verified that [Ca] equilibration apparently occurred in our experiments. Under these conditions, where both membrane potential and intracellular [Ca] were known, we found that the dependence of the channel percent open time on membrane potential and [Ca] was similar in both the cell- attached and excised patch configuration for several minutes after excision. Current-voltage relations were also similar, and autocorrelation functions constructed from the single channel currents revealed no obvious change in channel gating upon patch excision. These findings suggest that the results of studies that use excised membrane patches can be extrapolated to the K-depolarized cell-attached configuration, and that the relation between [Ca] and channel activity can be used to obtain a quantitative measure of [Ca] near the membrane intracellular surface

Interpersonal interactions in instrumental lessons: teacher/students verbal and non-verbal behaviours

This study examined verbal and non-verbal teacher/student interpersonal interactions in higher education instrumental music lessons. Twenty-four lessons were videotaped and teacher/ student behaviours were analysed using a researcher-designed instrument. The findings indicate predominance of student and teacher joke among the verbal behaviours with no substantial gender differences between males and females. Deceit cues were the most frequent among the non-verbal behaviours, with the males displaying more gestures of deceit than the females. Other gender differences include the female students using courting signals towards both teacher groups and the female teachers showing interest towards the male students. The presence of positive verbal and negative non-verbal behaviours highlights the mixed messages present in teaching. Implications for instrumental teaching practice include greater focus on gender differences in interpersonal interactions and visual cues to improve communication and teacher/student relationship in the instrumental studio

Teaching strategies and gender in higher education instrumental studios

This study investigates instrumental music teaching strategies in higher education settings, in order to identify those employed and their frequency and context of use. An instrument- and gender-balanced sample of 24 lessons from five institutions was analysed using a researcher-designed observational instrument. The results reveal the predominance of teacher demonstration, general directives and praise as most frequent teaching strategies employed in lessons. Gender differences emerged in the teaching approaches: the male teachers gave more general directives and explanations and the female teachers offered more answers and practice discussions; the male students received the most specific teacher criticism despite uniform use of praise. The findings provide new evidence of teaching practices in advanced instrumental studios and raise questions regarding gender issues in music teaching