Purification of Porphobilinogen Deaminase and the Sequencing and Expression of thehemC Gene of Rhodobacter Capsulatus.

Rhodobacter capsulatus uses the common tetrapyrrole pathway to synthesize heme, bacteriochlorophyll, siroheme and vitamin B-12. As part of our studies on the regulation of this pathway, the product of the hemC gene, porphobilinogen deaminase was purified approximately 200-fold. The molecular weight, isoelectric point, pH optimum and Km of the enzyme were all similar to other porphobilinogen deaminases. The stoichiometry of the enzyme was found not to be the expected four porphobilinogens used per one uroporphyrin formed. Rather a 9:1 ratio was typically seen. Further study of this atypical ratio uncovered evidence of possible in vivo regulation of porphobilinogen deaminase dependant on the cellular redox state. The protein was isolated from a two-dimensional gel and the sequence of the first twenty amino acids from the N-terminus was determined. This protein sequence matched a putative amino acid sequence 110 bp upstream of the R. capsulatus hemE gene. The putative hemC locus was subcloned from the plasmid pCAP154 which contains the R. capsulatus hemE gene with 1.2 Kb of upstream DNA. The sequence of the upstream DNA was determined by dideoxy sequencing of both strands. A single open reading frame of 951 bp was found which could code for a 317 amino acid protein of 34,082 Da. The putative protein has 49% identity with the E. coli porphobilinogen deaminase and 44% identity with the B. subtilis enzyme. When a plasmid carrying the R. capsulatus hemC was inserted into E. coli and R. capsulatus, a four-fold and ten-fold increase in porphobilinogen deaminase activity was seen respectively. The DNA sequence revealed that the hemC and hemE genes are divergently transcribed. A palindrome was identified between the two start sites, 47 bp upstream of hemE and 42 bp upstream of hemC. This palindrome, found upstream of many R. capsulatus genes, has been proposed to be a transcriptional regulatory site. The effects of oxygen on the transcription of hemC were studied using a hemC-cat fusion vector. Under the conditions tested, oxygen had no effect on the transcription of the R. capsulatus hemC gene

On the calibration of the relation between geometric albedo and polarimetric properties for the asteroids

We present a new extensive analysis of the old problem of finding a satisfactory calibration of the relation between the geometric albedo and some measurable polarization properties of the asteroids. To achieve our goals, we use all polarimetric data at our disposal. For the purposes of calibration, we use a limited sample of objects for which we can be confident to know the albedo with good accuracy, according to previous investigations of other authors. We find a new set of updated calibration coefficients for the classical slope - albedo relation, but we generalize our analysis and we consider also alternative possibilities, including the use of other polarimetric parameters, one being proposed here for the first time, and the possibility to exclude from best-fit analyzes the asteroids having low albedos. We also consider a possible parabolic fit of the whole set of data.Comment: Accepted by MNRA

Where Land Meets Water: Understanding Wetlands of the Great Lakes

This publication summarizes the current state of knowledge about Great Lakes coastal wetlands based on the information presented at the Millennium Wetland Event symposium. Information on wetland development and classification, summaries of wetland vegetation communities, and details of the fish and wildlife species that use Great Lakes coastal wetlands as habitat are all found within the following pages. Wetland conservation initiatives and some of the challenges of performing wetland science in such a large and diverse environment are also highlighted

Rethinking Therapeutic Misconception in Biobanking : Ambivalence Between Research and Treatment

Peer reviewe

Digital Media Player Controls Supporting Music Education

non

Anxiety and depression in Canada during the COVID-19 pandemic: A national survey.

Depression and anxiety are the most prevalent mental health problems in Canada. The COVID-19 pandemic will likely result in a large increase in the incidence and prevalence of anxiety and depression and experts are already warning of an “echo pandemic” of mental health problems. The objective is this research was to explore how Canadians are managing with the COVID-19 outbreak and determine the impact of the pandemic on levels of anxiety and depression. A nationally representative sample of 1,803 participants completed an online survey that was offered in both official languages. The percentage of respondents who indicated that their anxiety was high to extremely high quadrupled (from 5% to 20%) and the number of participants with high self-reported depression more than doubled (from 4% to 10%) since the onset of COVID-19. Although current anxiety levels are expected to remain the same, respondents predicted that depression would worsen if physical distancing and self-isolation continue for another 2 months. One-third of Canadians with anxiety and depression also report an increase in alcohol and cannabis use during the pandemic. Canadians with depression and anxiety also indicate that the quantity and quality of mental health support systems has decreased. Finally, a sizable proportion of Canadians believe that the federal and provincial governments should do more to support the mental health of Canadians. Recommendations for psychologists responding to mental health needs during and following the pandemic are provided

Lack of Mutual Respect in Relationship The Endangered Partner

Violence in a relationship and in a family setting has been an issue of concern to various interest groups and professional organizations. Of particular interest in this article is violence against women in a relationship. While there is an abundance of knowledge on violence against women in general, intimate or partner femicide seems to have received less attention. Unfortunately, the incidence of violence against women, and intimate femicide in particular, has been an issue of concern in the African setting. This article examines the trends of intimate femicide in an African setting in general, and in Botswana in particular. The increase in intimate femicide is an issue of concern, which calls for collective effort to address. This article also examines trends offemicide in Botswana, and the antecedents and the precipitating factors. Some studies have implicated societal and cultural dynamics as playing significant roles in intimate femicide in the African setting. It is believed that the patriarchal nature of most African settings and the ideology of male supremacy have relegated women to a subordinate role. Consequently, respect for women in any relationship with men is lopsided in favor of men and has led to abuse of women, including intimate femicide. Other militating factors in intimate femicide ,are examined and the implications for counseling to assist the endangered female partner are discussed

Canadian infants' nutrient intakes from complementary foods during the first year of life

<p>Abstract</p> <p>Background</p> <p>Complementary feeding is currently recommended after six months of age, when the nutrients in breast milk alone are no longer adequate to support growth. Few studies have examined macro- and micro-nutrient intakes from complementary foods (CF) only. Our purpose was to assess the sources and nutritional contribution of CF over the first year of life.</p> <p>Methods</p> <p>In July 2003, a cross-sectional survey was conducted on a nationally representative sample of mothers with infants aged three to 12 months. The survey was administered evenly across all regions of the country and included a four-day dietary record to assess infants' CF intakes in household (tablespoon) measures (breast milk and formula intakes excluded). Records from 2,663 infants were analyzed for nutrient and CF food intake according to 12 categories. Mean daily intakes for infants at each month of age from CF were pooled and compared to the Dietary Reference Intakes for the respective age range.</p> <p>Results</p> <p>At three months of age, 83% of infants were already consuming infant cereals. Fruits and vegetables were among the most common foods consumed by infants at all ages, while meats were least common at all ages except 12 months. Macro- and micro-nutrient intakes from CF generally increased with age. All mean nutrient intakes, except vitamin D and iron, met CF recommendations at seven to 12 months.</p> <p>Conclusions</p> <p>Complementary foods were introduced earlier than recommended. Although mean nutrient intakes from CF at six to 12 months appear to be adequate among Canadian infants, further attention to iron and vitamin D intakes and sources may be warranted.</p

Optimal seismic upgrade timing in seaports with increasing throughput demand via real options

A real options (RO) formulation is proposed for decision-making on the timing to upgrade the seismic performance of existing seaports with increasing throughput demand in earthquake prone areas. The pay-off of the seismic upgrade investment option is estimated based on projected net earnings, repair cost, and downtime for a damaging reference seismic event having a pre-specified annual probability of occurrence. These projections inform a discrete-time RO binomial tree, following the American option valuation framework, which propagates the probability of the reference seismic event assuming Poisson temporal distribution of earthquake occurrence. The net present value of the expected annual payoff of the considered investment is used as an index supporting risk-informed decision-making discounted by the weighted average cost of capital (WACC). Numerical examples pertaining to decision makers with different capital cost, namely port authorities and terminal operators, operating in different economic environments typical of developed and developing countries are furnished to illustrate the applicability of the proposed RO formulation. It is found that high WACC and/or low throughput growth bring the optimal seismic upgrade timing forward, while earthquake consequences and upgrade cost have almost no influence on this timing