Sequence and Structural Differences between Enzyme and Nonenzyme Homologs

AbstractTo improve our understanding of the evolution of novel functions, we performed a sequence, structural, and functional analysis of homologous enzymes and nonenzymes of known three-dimensional structure. In most examples identified, the nonenzyme is derived from an ancestral catalytic precursor (as opposed to the reverse evolutionary scenario, nonenzyme to enzyme), and the active site pocket has been disrupted in some way, owing to the substitution of critical catalytic residues and/or steric interactions that impede substrate binding and catalysis. Pairwise sequence identity is typically insignificant, and almost one-half of the enzyme and nonenzyme pairs do not share any similarity in function. Heterooligomeric enzymes comprising homologous subunits in which one chain is catalytically inactive and enzyme polypeptides that contain internal catalytic and noncatalytic duplications of an ancient enzyme domain are also discussed

Gene expression differs in susceptible and resistant amphibians exposed to Batrachochytrium dendrobatidis.

Chytridiomycosis, the disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), has devastated global amphibian biodiversity. Nevertheless, some hosts avoid disease after Bd exposure even as others experience near-complete extirpation. It remains unclear whether the amphibian adaptive immune system plays a role in Bd defence. Here, we describe gene expression in two host species-one susceptible to chytridiomycosis and one resistant-following exposure to two Bd isolates that differ in virulence. Susceptible wood frogs (Rana sylvatica) had high infection loads and mortality when exposed to the more virulent Bd isolate but lower infection loads and no fatal disease when exposed to the less virulent isolate. Resistant American bullfrogs (R. catesbeiana) had high survival across treatments and rapidly cleared Bd infection or avoided infection entirely. We found widespread upregulation of adaptive immune genes and downregulation of important metabolic and cellular maintenance components in wood frogs after Bd exposure, whereas American bullfrogs showed little gene expression change and no evidence of an adaptive immune response. Wood frog responses suggest that adaptive immune defences may be ineffective against virulent Bd isolates that can cause rapid physiological dysfunction. By contrast, American bullfrogs exhibited robust resistance to Bd that is likely attributable, at least in part, to their continued upkeep of metabolic and skin integrity pathways as well as greater antimicrobial peptide expression compared to wood frogs, regardless of exposure. Greater understanding of these defences will ultimately help conservationists manage chytridiomycosis

About Women, Gender and Literature: An Interview with Janet Todd

During the annual AEDEAN conference held in Valladolid during the week of December 14th-20th, 1992, Professor Janet Todd was so kind as to grant us an interview. The text printed here is the result of that conversation

Hydrogeomorphic Factors and Ecosystem Responses in Coastal Wetlands of the Great Lakes

Gauging the impact of manipulative activities, such as rehabilitation or management, on wetlands requires having a notion of the unmanipulated condition as a reference. An understanding of the reference condition requires knowledge of dominant factors influencing ecosystem processes and biological communities. In this paper, we focus on natural physical factors (conditions and processes) that drive coastal wetland ecosystems of the Laurentian Great Lakes. Great Lakes coastal wetlands develop under conditions of largelake hydrology and disturbance imposed at a hierarchy of spatial and temporal scales and contain biotic communities adapted to unstable and unpredictable conditions. Coastal wetlands are configured along a continuum of hydrogeomorphic types: open coastal wetlands, drowned river mouth and Hooded delta wetlands, and protected wetlands, each developing distinct ecosystem properties and biotic communities. Hydrogeomorphic factors associated with the lake and watershed operate at a hierarchy of scales: a) local and short-term (seiches and ice action), b) watershed /lakewide /annual (seasonal water- level change), and c) larger or year-to-year and longer (regional and/or greater than one-year). Other physical factors include the unique water quality features of each lake. The aim of this paper is to provide scientists and managers with a framework for considering regional and site-specific geomorphometry and a hierarchy of physical processes in planning management and conservation projects

Commercial Space Transportation: A Simulation and Analysis of Operations Impacts on the United States National Airspace System and Airline Stakeholders

Agenda: Background on space launch activity Research problem and objective Methodology Results Implications Future researc

A Qualitative Examination of Youth Voice in the Decision-Making Process within the 4-H Youth Development Program: Promoting Promising Practices in Overcoming Barriers

This paper discusses a national study designed to identify and describe obstacles to youth voice in the decision-making process in the 4-H youth development program from the perception of three distinct populations - State 4-H Program Leaders, 4-H State Youth Development Specialists, and 4-H Youth Agents/Educators. When examining these professionals’ views on the barriers affecting youth voice in the decision-making process, time and scheduling seem to consistently present the largest barrier to youth voice. Involvement in the decision-making process provides a wide range of hurdles including the opportunity structures, involvement procedures, representation and dynamics within the process. Adult power and control provides a significant hurdle to authentic engagement of youth voice in the decision-making progress. Respect barriers were described by concepts such as preconceived notions, trust and valuing input. Additional barriers were identified including organizational culture, lack of transportation, lack of knowledge/experience, lack of preparation, lack of training, fear, misguided leadership, unclear expectations, participation, staffing and lack of resources

Palliative care in primary care: A study to determine whether patients and professionals agree on symptoms

BACKGROUND: Difficulties in managing symptoms of palliative care patients at home have been identified, yet there has been no investigation of agreement on symptom assessment in primary care. Lack of agreement between patients' and primary care professionals' symptom assessments may be contributing to difficulties in symptom control. AIM: To investigate agreement on symptom assessments between patients at home and GPs and district nurses. DESIGN OF STUDY: Prospective, self-completed, structured symptom assessments. SETTING: Routine contacts with adult palliative care patients estimated to be in their last year of life. METHOD: Patient and professional symptom assessments were obtained using CAMPAS-R, a comprehensive and reliable measure validated for palliative care in the community. Prevalence of reported symptoms was calculated in patient–professional pairs. Intraclass correlation techniques (ICCs) and percentage agreement were used to determine how well symptom assessments of patients and professionals agreed. RESULTS: Anxiety and depression were significantly more likely to be reported by professionals, and GPs over-identified nausea, vomiting and constipation. Professionals assessed emotional symptoms as more severe than patients. Agreement on scoring of physical symptoms was better, although this was at least partially due to agreement on absence of symptoms. Unlike previous reports, pain scores recorded by doctors in this study, were not significantly different from patients. CONCLUSION: This quick and easy to complete assessment tool, CAMPAS-R, has potential for monitoring quality of palliative care symptom control at home