Domain specific interaction of S-RNase binding protein with the stylar 120 kDA glycoprotein in nicotiana [abstract]

Abstract only availableThrough the process of evolution, many flowering plants have developed a biochemical mechanism to prevent self-pollination and pollination by closely related plants. Gametophytic self-incompatibility (SI) is one such system that prevents inbreeding, a well-known disadvantage for organisms. In Nicotiana, this SI mechanism is controlled by the S-locus and genes located within this locus. The S-locus encodes two highly polymorphic proteins that are directly responsible for the recognition and rejection of self-pollen, S-RNase and SLF/SFB an F-box protein. Non-S-RNase factors also play a key role in SI. The 120 kDa glycoprotein (120K) and HT-B are two style proteins known to be involved in SI. Recent research has revealed that without 120K or HT-B the SI mechanism doesn't work, thus rendering the plants self-compatible (SC). In a previous experiment, the C-terminus of 120K (120K CTD) was used as bait in a yeast-two hybrid (Y2H) screen of pollen and pistil proteins. These experiments revealed that several proteins interacted with the 120K CTD. One of these proteins was the S-RNase Binding Protein (NaSBP1). NaSPB1's interaction with 120K CTD suggests that it could be involved in SI. In vitro binding assays demonstrated that 120K CTD interacts with full length NaSBP1, but which part of the protein is responsible for this interaction? NaSPB1 consists of a 120 amino acid (aa) N-terminal domain, a 165 aa helical domain and a 47 aa RING HC domain. NaSBP1 has been cloned into pMAL-C2xMBP, an N-terminal fusion expression vector. Six different MBP::NaSBP1 fusion constructs have been designed from the three different domains of NaSBP1. Binding experiments (pull-down assays) with domain specific MBP::SBP1 clones will be performed to see what domain or domains are responsible for the interaction with 120K CTD. This will ultimately lead to a greater understanding of how the gametophytic SI mechanism works in Nicotiana.MU Monsanto Undergraduate Research Fellowshi

Cardiopulmonary exercise testing for high-risk South African surgical patients.

Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2007.Aim: To determine the prognostic value of cardiopulmonary exercise testing (CPET) for major vascular surgery in South African patients. Methods: CPET has been used in Durban since October 2004 to predict cardiac risk for high-risk patients undergoing major vascular surgery. A submaximal 'anaerobic threshold' (AT) test was conducted on all high-risk patients. Patients were classified into two groups: 'low AT' where the oxygen consumption at the AT was <1 lml.kg^.min"1 for cycling or < 9ml.kg"1.mkf1 for arm cranking and 'high AT' when the patient surpassed these targets. Analysis of all in-hospital deaths following surgery was conducted by two independent assessors blinded to the CPET test result. Deaths classified as primarily 'cardiac in origin' have been used in this retrospective cohort analysis. Results: The AT measured during CPET was not a statistically significant pre-operative prognostic marker of cardiac mortality. However, the survivors of the patients with a 'low AT' may be identified by their response to increasing metabolic demand between 5 and 7 ml.kg^.min"1. Survivors were more dependent on increasing heart rate, while non-survivors were more dependent on oxygen extraction. When this information is added to the AT, CPET was the only test statistically associated with cardiac mortality, in comparison to Lee's Revised Cardiac Risk Index and the resting left ventricular ejection fraction which were not statistically associated with cardiac death. A hundred percent of patients with a positive test died of cardiac causes, while 11% of the patients with a negative test had cardiac deaths. The risk ratio associated with cardiac death following a positive test was 8.00 [95% CI 3.8-16.9]. The sensitivity was 0.25 [95% CI 0.04-0.64], the specificity was 1.00 [95% CI 0.90-1.00], the positive predictive value was 1.00 [95% CI 0.20-0.95] and the negative predictive value was 0.88 [95% CI 0.74-0.95]. Conclusions: CPET provides valuable prognostic information in our surgical population

Science Outreach and Informal Science Education-Programs and Partnerships [abstract]

Comparative Medicine - OneHealth and Comparative Medicine Poster SessionOur vision is to create a culture where engagement between scientists and the public is the norm. This will contribute to workforce development, public understanding of science and its economic impacts in our state. We are creating opportunities for exchange between scientists and the public and training graduate students to regard public engagement as an ordinary part of professional life. We are looking for partners to sustain and expand these efforts. Our approaches: Saturday Morning Science (SMS) is a free public lecture series held at MU every Saturday throughout the fall and winter semesters. Talks are geared toward the general public and include a two-way engagement between scientists and the public. SMS has established its reputation by presenting scientific ideas and concepts in a lively, engaging, and accessible manner. Audiences include K-12 students and teachers, retirees, and MU students, among others. Largely through word-of-mouth, interest in SMS has grown tremendously. We have held over 145 presentations with approximately 18,000 total attendees. Science Talks to You (STTY) is SMS's new off-campus offshoot. Like SMS, STTY will feature direct engagement between established scientists and the public, but in venues around Missouri including communities distant from museums, science centers, and research universities. Our plan is to visit specific communities several times over a period of a few years ensuring a significant impact for a manageable cost. Science and Me (SaM) is a public lecture series offered by graduate students in MU's "Public Understanding of Science" course designed by Dr. Hannah Alexander. Students are mentored as they develop presentations focusing on science in everyday life. Their presentations are given to adult audiences in venues such as libraries and assisted-living facilities. Students gain an understanding of how science fits into the lives of audience members and how to communicate effectively to non-scientists. Audience members gain an appreciation for the role of science in their lives and also for the perspectives of young scientists. In fall 2008, SaM hosted 31 presentations in seven venues with audiences totaling nearly 500. Approximately 25 presentations are planned for early 2010. Sustaining These Programs: Despite wide recognition of the need for engagement between scientists and the public, sustaining these programs is a challenge. SMS has succeeded largely with volunteer effort and modest support from MU's Office of Research and Bookstore. Monsanto recently made a gift that will extend SMS, pilot STTY presentations, and SaM in 2010. Dr. Alexander teaches her course and organizes SaM without salary support. The greatest needs are for salary and graduate student support. To realize our vision of cultural change we propose a new kind of graduate assistantship…not teaching assistants, but outreach assistants. These would be students skilled in both science and science communication. We need to identify partners who share this vision and can help make it a reality

Economic crisis and smoking behaviour: prospective cohort study in Iceland

Objective: To examine the associations between the 2008 economic collapse in Iceland and smoking behaviour at the national and individual levels. Design: A population-based, prospective cohort study based on a mail survey (Health and Wellbeing in Iceland) assessed in 2007 and 2009. Setting: National mail survey. Participants: Representative cohort (n=3755) of Icelandic adults. Main outcome measure: Smoking status. Results: A significant reduction in the prevalence of smoking was observed from 2007 (pre-economic collapse) to 2009 (postcollapse) in both males (17.4–14.8%; p 0.01) and females (20.0–17.5%; p 0.01) in the cohort (n=3755). At the individual level of analysis, male former smokers experiencing a reduction in income during the same period were less likely to relapse (OR 0.37; 95% CI 0.16 to 0.85). Female smokers were less likely to quit over time compared to males (OR 0.65; 95% CI 0.45 to 0.93). Among male former smokers who experienced an increase in income between 2007 and 2009, we observed an elevated risk of smoking relapse (OR 4.02; 95% CI 1.15 to 14.00). Conclusions: The national prevalence of smoking in Iceland declined following the 2008 economic crisis. This could be due to the procyclical relationship between macro-economic conditions and smoking behaviour (ie, hard times lead to less smoking because of lower affordability), or it may simply reflect a continuation of trends already in place prior to the crisis. In individual-level analysis, we find that former smokers who experienced a decline in income were less likely to relapse; and conversely, an increase in income raises the risk. However, caution is warranted since these findings are based on small numbers

An Experimental Study of Effects of Overlaying Tissues on HIFU Lesion

Understanding the effect of overlaying tissues on HIFU lesion is crucial for estimating HIFU dose distribution at a target tissue. We have run a series of experiments to systematically observe the effects of the overlaying tissues on the HIFU beam and ultimately the lesion created in the target tissue. First, we mapped out the HIFU transducer beam (in low power) under water without and with different overlaying tissue layers. Then, we performed a series of experiments in high power to create lesions in target tissues (e.g., liver) without and with overlaying tissues (e.g. muscle). The lesions are characterized by slicing the tissues and reconstructing the 3D lesion from calibrated pictures of the target tissue slices. The low power beam measurements show significant effects in terms of severe beam wave‐field amplitude distortion due to phase aberration introduced by velocity inhomogeneity in the overlaying tissues. These results compare well qualitatively with the computational models. The results from the high power HIFU lesions in a similar setup using various tissues, including liver and muscle, provide understanding of the significance of phase aberration in overlaying tissues and could prove useful towards high precision HIFU therapy

Differential in-gel electrophoresis (DIGE): The key to finding the 4936 factor? [abstract]

Abstract only availableThere are many species of plants that do not accept their own or closely related pollen. This self-incompatibility (SI), is seen in members of the genus Nicotiana. There are three proteins that are known to be required for SI to function in the pistil: S-RNase, 120K and HT-B. We discovered a mutation segregating in a population of otherwise SI plants that prevents SI from functioning in the pistil. Plants that display normal SI are called Rejectors (because they reject their own pollen), and mutants are called Acceptors (because they accept their own pollen). Acceptors show normal expression of S-RNase, 120K, and HT-B. The factor responsible for the mutation was named the 4936 Factor after the population in which it was first discovered. In order to Identify the 4936 Factor, I have used the DIGE method. Total protein extracts from Acceptor and Rejector pistils are stained with two different fluorophores and run in the same two-dimensional gel. By separating proteins both by size and isoelectric point, one can search for differences in the expression level or presence/absence of a particular protein. Therefore, a protein that is present in the rejector color, but not in the acceptor color, is a good candidate for further investigation as the 4936 Factor.MU Monsanto Undergraduate Research Fellowshi

A Spectroscopic and Photometric Study of the Metal-Poor, Pulsating, Post-AGB Binary HD 46703

The metal-poor post-AGB star HD 46703 is shown to be a single-line spectroscopic binary with a period of 600 days, a high velocity of -94 km/s, and an orbital eccentricity of 0.3. Light curve studies show that it also pulsates with a period of 29 days. High-resolution, high signal-to-noise spectra were used for a new abundance study. The atmospheric model determined is T(eff) = 6250 K, log(g) = 1.0, V(t) = 3.0 km/s, and a metal abundance of [M/H] = -1.5. A low carbon abundance and lack of s-process element enhancement indicate that the star has not experienced third dredge-up on the AGB. The sulfur and zinc abundances are high compared with iron, and the chemical abundances show a clear anti-correlation with condensation temperature. The abundance depletion pattern is similar to that seen in other post-AGB binaries, and, like them, is attributed to the chemical fractionation of refractory elements onto dust stored in a circumbinary disk and the re-accretion of volatiles in the stellar atmosphere. The infrared excess is small but the excess energy distribution is very similar to what can expected from a disk. HD 46703 joins the growing list of depleted, post-AGB stars which are likely surrounded by a dusty and stable circumbinary disk.Comment: Machine readable files not include

Management of failed spinal anaesthesia for caesarean section

Background. Failed spinal anaesthesia for caesarean section (CS) may be partial or complete and the subsequent discomfort is the most commonly cited cause of litigation in obstetric anaesthesia.Objectives. To determine if there is a standardised approach to: (i) testing the level of block of spinal anaesthesia; and (ii) the management of failed spinal anaesthesia for CS.Methods. A structured questionnaire to ascertain the current practice of testing the level of block and management of three different scenarios of failed spinal anaesthesia was distributed to 51 government hospitals in KwaZulu-Natal, South Africa (SA). All obstetric anaes­thetic service providers, ranging from interns to specialist anaesthetists, were invited to complete the questionnaire.Results. A total of 375 responses were received from 42 of the 51 hospitals surveyed. Specialist anaesthetists managed failure of spinal anaesthesia significantly differently than other anaesthetic service providers. Specialists were more likely to convert to a general anaesthetic (GA), while others were more likely to repeat spinal anaesthesia or administer intravenous ketamine, midazolam and opioids. Only 212 respondents (56%) tested the level of block and there was no difference between the groups with regard to the method of assessment of height (p=0.15). Non-specialists, however, accepted a significantly lower level of block, using pinprick, than specialists (p=0.027), which could lead to a higher failure rate. More than one-third of non-specialists did not consider themselves competent to perform a GA and &gt;90% of respondents agreed that a ‘failed’ spinal algorithm would be useful.Conclusion. There is a need for standardised assessment of the adequacy of spinal anaesthesia for CS in SA, as well as a failed spinal algorithm.

Management of failed spinal anaesthesia for caesarean section

Background. Failed spinal anaesthesia for caesarean section (CS) may be partial or complete and the subsequent discomfort is the most commonly cited cause of litigation in obstetric anaesthesia. Objectives. To determine if there is a standardised approach to: (i) testing the level of block of spinal anaesthesia; and (ii) the management of failed spinal anaesthesia for CS. Methods. A structured questionnaire to ascertain the current practice of testing the level of block and management of three different scenarios of failed spinal anaesthesia was distributed to 51 government hospitals in KwaZulu-Natal, South Africa (SA). All obstetric anaes­thetic service providers, ranging from interns to specialist anaesthetists, were invited to complete the questionnaire. Results. A total of 375 responses were received from 42 of the 51 hospitals surveyed. Specialist anaesthetists managed failure of spinal anaesthesia significantly differently than other anaesthetic service providers. Specialists were more likely to convert to a general anaesthetic (GA), while others were more likely to repeat spinal anaesthesia or administer intravenous ketamine, midazolam and opioids. Only 212 respondents (56%) tested the level of block and there was no difference between the groups with regard to the method of assessment of height (p=0.15). Non-specialists, however, accepted a significantly lower level of block, using pinprick, than specialists (p=0.027), which could lead to a higher failure rate. More than one-third of non-specialists did not consider themselves competent to perform a GA and >90% of respondents agreed that a ‘failed’ spinal algorithm would be useful. Conclusion. There is a need for standardised assessment of the adequacy of spinal anaesthesia for CS in SA, as well as a failed spinal algorithm

Pollination in Nicotiana alata stimulates synthesis and transfer to the stigmatic surface of NaStEP, a vacuolar Kunitz proteinase inhibitor homologue

After landing on a wet stigma, pollen grains hydrate and germination generally occurs. However, there is no certainty of the pollen tube growth through the style to reach the ovary. The pistil is a gatekeeper that evolved in many species to recognize and reject the self-pollen, avoiding endogamy and encouraging cross-pollination. However, recognition is a complex process, and specific factors are needed. Here the isolation and characterization of a stigma-specific protein from N. alata, NaStEP (N. alata Stigma Expressed Protein), that is homologous to Kunitz-type proteinase inhibitors, are reported. Activity gel assays showed that NaStEP is not a functional serine proteinase inhibitor. Immunohistochemical and protein blot analyses revealed that NaStEP is detectable in stigmas of self-incompatible (SI) species N. alata, N. forgetiana, and N. bonariensis, but not in self-compatible (SC) species N. tabacum, N. plumbaginifolia, N. benthamiana, N. longiflora, and N. glauca. NaStEP contains the vacuolar targeting sequence NPIVL, and immunocytochemistry experiments showed vacuolar localization in unpollinated stigmas. After self-pollination or pollination with pollen from the SC species N. tabacum or N. plumbaginifolia, NaStEP was also found in the stigmatic exudate. The synthesis and presence in the stigmatic exudate of this protein was strongly induced in N. alata following incompatible pollination with N. tabacum pollen. The transfer of NaStEP to the stigmatic exudate was accompanied by perforation of the stigmatic cell wall, which appeared to release the vacuolar contents to the apoplastic space. The increase in NaStEP synthesis after pollination and its presence in the stigmatic exudates suggest that this protein may play a role in the early pollen–stigma interactions that regulate pollen tube growth in Nicotiana