Eurycea tridentifera

Number of Pages: 2Integrative BiologyGeological Science

Pituophis melanoleucus

Number of Pages: 8Integrative BiologyGeological Science

The role of protein kinases in DNA replication in Saccharomyces cerevisiae

The initiation of DNA replication at the onset of S phase in eukaryotic cells is a critically important and tightly regulated process. Multiple origins of replication in the genome must be co-ordinately regulated such that duplication of the chromosomes is complete before cell division, whilst also ensuring that no sections of the DNA are over-replicated. In G1 phase of the cell cycle, a large ‘pre-replicative complex’ (pre-RC) forms at origins consisting of a hexameric Origin Recognition Complex (ORC) as well as Cdc6, Cdt1 and another hexameric complex known as the Minichromosome Maintenance (MCM) complex. At the onset of S phase, two cell cycle regulated protein kinases, the Cyclin Dependent Kinase (CDK) and Cdc7, are activated. Phosphorylation of various proteins by these two enzymes triggers formation of large ‘replisome’ complexes, initiation of DNA replication from each origin, and disassembly of the pre-RCs. Pre-RC re-assembly is subsequently inhibited until kinase activity falls again after cell division. In this study, we have set about identifying substrates of both CDK and Cdc7 involved in DNA replication in the budding yeast Saccharomyces cerevisiae. Two techniques are employed, the in vitro phosphorylation of arrays of peptides and phosphorylation of pre-RCs assembled in cell-free yeast extracts. Peptide arrays provide a high throughput technique for screening large numbers of potential substrates in a single experiment, whilst pre-RC phosphorylation allows consideration of both tertiary and quaternary structures of the in vivo kinase substrate. Several potential novel substrates of both CDK and Cdc7 are revealed. Pre-RC phosphorylation also reveals a previously unreported phosphorylation of Orc1 by a third kinase which has been identified as Casein Kinase II (CKII)

Database Search Strategies for Proteomic Data Sets Generated by Electron Capture Dissociation Mass Spectrometry

Large data sets of electron capture dissociation (ECD) mass spectra from proteomic experiments are rich in information; however, extracting that information in an optimal manner is not straightforward. Protein database search engines currently available are designed for low resolution CID data, from which Fourier transform ion cyclotron resonance (FT-ICR) ECD data differs significantly. ECD mass spectra contain both z-prime and z-dot fragment ions (and c-prime and c-dot); ECD mass spectra contain abundant peaks derived from neutral losses from charge-reduced precursor ions; FT-ICR ECD spectra are acquired with a larger precursor m/z isolation window than their low-resolution CID counterparts. Here, we consider three distinct stages of postacquisition analysis: (1) processing of ECD mass spectra prior to the database search; (2) the database search step itself and (3) postsearch processing of results. We demonstrate that each of these steps has an effect on the number of peptides identified, with the postsearch processing of results having the largest effect. We compare two commonly used search engines: Mascot and OMSSA. Using an ECD data set of modest size (3341 mass spectra) from a complex sample (mouse whole cell lysate), we demonstrate that search results can be improved from 630 identifications (19% identification success rate) to 1643 identifications (49% identification success rate). We focus in particular on improving identification rates for doubly charged precursors, which are typically low for ECD fragmentation. We compare our presearch processing algorithm with a similar algorithm recently developed for electron transfer dissociation (ETD) data

Building Social Skills: A Qualitative Study of Relationships Between Stay-At-Home Fathers and Their Preschool Children

Building social skills: A qualitative study of relationships between stay-at-home fathers (SAHF) and their 2.5 to 4-year-old children is a presentation of two SAHF-child dyad case studies. With the rise in the number of SAHFs, observational data between SAHFs and their children is lacking in the literature. The purpose and primary focus of this study was to examine the interactions between SAHFs and their preschool children, focusing on father involvement. A secondary focus for this study was to explore the availability and responsibility of SAHFs with their preschool children. Two research questions guided this study: 1.) “What types of interactions occur between SAHFs with their 2.5 to 4-year-old children?” and 2.) “What are the thoughts of SAHFs when interacting with their children?” Data for each case study consisted of an initial interview with the SAHF, two observations between the SAHF and child, and two stimulated recall interviews within 48 hours of observations. Themes found with Case Study One, Dan and Lou were teaching social skills, communication, “big kid,” basketball techniques, entertain herself, taking care of physical needs of child, sarcasm, know your child, “mindful,” and not missing out. Themes with Case Study Two, Arnie and Sally were teaching, “showing affection,” caring for Sally’s needs, safety concerns, “remaining engaged,” “just a bonding thing,” “let her figure it out,” and “testing boundaries.” This study provides insight to the types of interactions observed between SAHFs and preschool children and SAHFs’ thoughts behind these interactions

Letter from J. S. Sweet to B. R. Colson

Letter from J. S. Sweet to B. R. Colson dated 11 January 1913. The hand-written letter is three pages long. There is a typewritten transcript of the document included in the item PDF

Study of quiet turbofan STOL aircraft for short haul transportation

Conceptual designs of Quiet Turbofan STOL Short-Haul Transport Aircraft for the mid-1980 time period are developed and analyzed to determine their technical, operational, and economic feasibility. A matrix of aircraft using various high-lift systems and design parameters are considered. Variations in aircraft characteristics, airport geometry and location, and operational techniques are analyzed systematically to determine their effects on the market, operating economics, and community acceptance. In these studies, the total systems approach is considered to be critically important in analyzing the potential of STOL aircraft to reduce noise pollution and alleviate the increasing air corridor and airport congestion