Characterization of the Interaction between Arabidopsis Toc159 and Toc33 GTPase Domains

Protein-protein interactions are critical for many biochemical processes and for cellular function. Understanding interactions between proteins and ligands, as well as other proteins are necessary for the modelling of biological systems. Protein import into chloroplasts is one such system where the understanding of interactions between members of the translocation complex is limited. The translocon at the outer envelope membrane of chloroplasts (Toe complex) consists of three core components: Toc75, Tocl59, and Toc34. Members of the Tocl59 and Toc34 gene families in Arabidopsis thaliana have been shown to assemble differentially into structurally and functionally distinct complexes. More specifically, there is evidence that complexes containing atTocl59 and atToc33 (the prefix “at” identifies the species of origin, Arabidopsis thaliana) import photosynthetic proteins, whereas complexes containing atTocl32/120 and atToc34 seem to preferentially import non-photosynthetic proteins. The interactions between atTocl59 and atToc33 or atTocl32 and atToc34 are mediated by their GTPase domains. The current research used recombinant GTPase domains to investigate the specifics of the interaction between atTocl59G and atToc33G in more detail using molecular and biophysical approaches. Methods included using blue-native PAGE, fluorescence spectroscopy and circular dichroism spectroscopy to characterize the interaction between atTocl59G and atToc33G. Objectives were to characterize the interaction between atTocl59G and atToc33G as well as attempt to manipulate the monomendimer equilibrium for individual proteins for the purpose of studying heterodimer formation. A secondary objective was to generate single tryptophan mutants of atTocl59G (W973F and W1056F) to more precisely characterize the interaction between proteins. Results indicate that only a small percentage of the total protein exists as heterodimers, making quantification using fluorescence spectroscopy and circular dichroism spectroscopy difficult. Nonetheless, it was demonstrated that heterodimer formation occurs between the G-domains of atTocl59 and atToc33. The data also suggest that higher order oligomers may form, which may be indicative of multiple interaction domains among proteins as previously suggested by stoichiometric studies on isolated Toe complexes. The effects of chelating agents, such as EDTA and Chelex, produced significant structural changes which also inhibited homo-dimerization indicating the specific need for GTP-nucleotide to maintain a functional conformation. Single tryptophan mutants of atTocl59G also produced major structural changes to recombinant proteins highlighting the importance of these residues for overall structure of the protein

Policy responses to invasive native species: issues of social and private benefits and costs

Farm and catchment managers in Australia face decisions about controlling invasive native species (or scrub) which may infest agricultural land. The treatment of this land to remove the infestation and re-establish native pastures is likely to be expensive for landholders. Yet there are potential social benefits from such remediation and so a policy question arises of what to do to about facilitating such change. New South Wales state government legislation addresses this issue through regulations, and the Catchment Management Authorities are responsible for administering public funds to achieve associated natural resource improvements. However, the extent of the private costs and social benefits associated with such changes are not known, which precludes benefit-cost analyses using the traditional welfare economics framework. This paper reports results of a social and private economic analysis of the impacts of a typical infestation remediation decision. We show that for the landholder the private costs exceed the benefits achieved from increased livestock productivity. However, there are social benefits expressed by the willingness to pay by members of the local catchment community for improvements in native vegetation and biodiversity. When these social benefits are included, the economic analysis shows a positive social net benefit. This raises questions of how to reconcile the public and private accounting, and whether any changes to policies, regulations or procedures for natural resource management in New South Wales are warranted.Invasive native scrub, environmental values, choice modelling, financial, economic, Namoi catchment,

Extracellular Matrix Mineralization Promotes E11/gp38 Glycoprotein Expression and Drives Osteocytic Differentiation

Osteocytes are terminally differentiated osteoblasts which reside in a mineralized extracellular matrix (ECM). The factors that regulate this differentiation process are unknown. We have investigated whether ECM mineralization could promote osteocyte formation. To do this we have utilised MLO-A5 pre-osteocyte-like cells and western blotting and comparative RT-PCR to examine whether the expression of osteocyte-selective markers is elevated concurrently with the onset of ECM mineralization. Secondly, if mineralization of the ECM is indeed a driver of osteocyte formation, we reasoned that impairment of ECM mineralization would result in a reversible inhibition of osteocyte formation. Supplementation of MLO-A5 cell cultures with ascorbic acid and phosphate promoted progressive ECM mineralization as well as temporally associated increases in expression of the osteocyte-selective markers, E11/gp38 glycoprotein and sclerostin. Consistent with a primary role for ECM mineralization in osteocyte formation, we also found that inhibition of ECM mineralization, by omitting phosphate or adding sodium pyrophosphate, a recognized inhibitor of hydroxyapatite formation, resulted in a 15-fold decrease in mineral deposition that was closely accompanied by lower expression of E11 and other osteocyte markers such as Dmp1, Cd44 and Sost whilst expression of osteoblast markers Ocn and Col1a increased. To rule out the possibility that such restriction of ECM mineralization may produce an irreversible modification in osteoblast behaviour to limit E11 expression and osteocytogenesis, we also measured the capacity of MLO-A5 cells to re-enter the osteocyte differentiation programme. We found that the mineralisation process was re-initiated and closely allied to increased expression of E11 protein after re-administration of phosphate or omission of sodium pyrophosphate, indicating an ECM mineralization-induced restoration in osteocyte formation. These results emphasise the importance of cell-ECM interactions in regulating osteoblast behaviour and, more importantly, suggest that ECM mineralization exerts pivotal control during terminal osteoblast differentiation and acquisition of the osteocyte phenotype

Evaluation of yam-based production enterprises in Nigeria

This research investigated yam based production enterprise in Nigeria to identify the ideal farming system for yam. Data were extracted from 360 respondents in selected major yam-producing States in Nigeria. Data were analysed by the use of descriptive statistics and economic analysis. The result of this investigation reveals that yam production is profitable but it requires a large capital outlay. Yam production was more profitable that other comparable crops. There are infinite cropping systems for yam in Nigeria. All the dominant cropping systems for yam are profitable. Yam/maize intercropping system is the most profitable crop system for yam in Nigeria. The key recommendations from this research are increased investment in yam production; adoption of Yam/Maize intercropping system; and the development of an appropriate yam production technique that will reduce the cost of yam and make its production more profitable

Emerging patterns in the distribution of trace elements in ovarian, invasive and in-situ breast cancer

Breast cancer is the most common cancer and ovarian cancer is the 8th most common cancer affecting women worldwide. This study highlights the changes of trace element levels accompanied by the progression from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) of the breast, using micro probe Synchrotron Radiation X-ray Fluorescence (μSRXRF). The average values for the increase in Ca, Fe and Zn in tumour regions with respect to surrounding regions for the DCIS samples were significantly higher compared to the increase in the IDC samples (P <0.01).This study was also carried out to find a connection between ovarian cancer and breast cancer with respect to the cellular distribution of Ca, Cu, Fe, and Zn. For IDC, DCIS and ovarian cases, the statistical analysis reveals a significant increase in the levels of Ca, Cu and Zn concentrations in cancer tissue when compared to the normal surrounding tissue. For Fe, the differences between tumour regions with respect to surrounding regions were found to be not significant in IDC and ovarian cases. In DCIS cases, the results reveal a significant increase in the levels of Fe in cancer tissue when compared to the surrounding normal breast tissue (P <0.01)

Ten steps to conducting a large, multi-site, longitudinal investigation of language and reading in young children

Purpose: This paper describes methodological procedures involving execution of a large-scale, multi-site longitudinal study of language and reading comprehension in young children. Researchers in the Language and Reading Research Consortium (LARRC) developed and implemented these procedures to ensure data integrity across multiple sites, schools, and grades. Specifically, major features of our approach, as well as lessons learned, are summarized in 10 steps essential for successful completion of a large-scale longitudinal investigation in early grades. Method: Over 5 years, children in preschool through third grade were administered a battery of 35 higher- and lower-level language, listening, and reading comprehension measures (RCM). Data were collected from children, their teachers, and their parents/guardians at four sites across the United States. Substantial and rigorous effort was aimed toward maintaining consistency in processes and data management across sites for children, assessors, and staff. Conclusion: With appropriate planning, flexibility, and communication strategies in place, LARRC developed and executed a successful multi-site longitudinal research study that will meet its goal of investigating the contribution and role of language skills in the development of children’s listening and reading comprehension. Through dissemination of our design strategies and lessons learned, research teams embarking on similar endeavors can be better equipped to anticipate the challenges

Oblique internal hydraulic jumps at a stratified estuary mouth

Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 47 (2017): 85-100, doi:10.1175/JPO-D-15-0234.1.Observations and analyses of two tidally recurring, oblique, internal hydraulic jumps at a stratified estuary mouth (Columbia River, Oregon/Washington) are presented. These hydraulic features have not previously been studied due to the challenges of both horizontally resolving the sharp gradients and temporally resolving their evolution in numerical models and traditional observation platforms. The jumps, both of which recurred during ebb, formed adjacent to two engineered lateral channel constrictions and were identified in marine radar image time series. Jump occurrence was corroborated by (i) a collocated sharp gradient in the surface currents measured via airborne along-track interferometric synthetic aperture radar and (ii) the transition from supercritical to subcritical flow in the cross-jump direction via shipborne velocity and density measurements. Using a two-layer approximation, observed jump angles at both lateral constrictions are shown to lie within the theoretical bounds given by the critical internal long-wave (Froude) angle and the arrested maximum-amplitude internal bore angle, respectively. Also, intratidal and intertidal variability of the jump angles are shown to be consistent with that expected from the two-layer model, applied to varying stratification and current speed over a range of tidal and river discharge conditions. Intratidal variability of the upchannel jump angle is similar under all observed conditions, whereas the downchannel jump angle shows an additional association with stratification and ebb velocity during the low discharge periods. The observations additionally indicate that the upchannel jump achieves a stable position that is collocated with a similarly oblique bathymetric slope.We acknowledge the financial support of the Office of Naval Research under Awards N00014-10-1-0932 and N00014-13-1-0364.2017-07-0

Patient experience of lasting negative effects of psychological interventions for anxiety and depression in secondary mental health care services: a national cross-sectional study

Background Patients who undergo psychological treatment can report both negative and positive effects, but evidence of factors influencing the likelihood of negative effects is limited. Aims To identify aspects of the organisation and delivery of secondary care psychological treatment services that are associated with patient experiences of negative effects. Method Cross-sectional survey of people with anxiety and depression who ended psychological treatment delivered by 50 NHS trusts in England. Respondents were asked about how their treatment was organised and delivered and whether they experienced lasting negative effects. Results Of 662 respondents, 90 (14.1%) reported experiencing lasting negative effects. People over the age of 65 were less likely than younger respondents to report negative effects. There was an association between reporting neutral or negative effects and not being referred at what respondents considered to be the right time (OR = 1.712, 95% CI = 1.078–2.726), not receiving the right number of sessions (OR = 3.105, 95% CI = 1.934–4.987), and not discussing progress with their therapist (OR 2.063, 95% CI = 1.290–3.301). Conclusions One in seven patients who took part in this survey reported lasting negative effects from psychological treatment. Steps should be taken to prepare people for the potential for negative experiences of treatment, and progress reviewed during therapy in an effort to identify and prevent negative effects