Binding specificity of Bacillus thuringiensis Cry1Aa for purified, native Bombyx mori aminopeptidase N and cadherin-like receptors

BACKGROUND: To better understand the molecular interactions of Bt toxins with non-target insects, we have examined the real-time binding specificity and affinity of Cry1 toxins to native silkworm (Bombyx mori) midgut receptors. Previous studies on B. mori receptors utilized brush border membrane vesicles or purifed receptors in blot-type assays. RESULTS: The Bombyx mori (silkworm) aminopeptidase N (APN) and cadherin-like receptors for Bacillus thuringiensis insecticidal Cry1Aa toxin were purified and their real-time binding affinities for Cry toxins were examined by surface plasmon resonance. Cry1Ab and Cry1Ac toxins did not bind to the immobilized native receptors, correlating with their low toxicities. Cry1Aa displayed moderate affinity for B. mori APN (75 nM), and unusually tight binding to the cadherin-like receptor (2.6 nM), which results from slow dissociation rates. The binding of a hybrid toxin (Aa/Aa/Ac) was identical to Cry1Aa. CONCLUSIONS: These results indicate domain II of Cry1Aa is essential for binding to native B. mori receptors and for toxicity. Moreover, the high-affinity binding of Cry1Aa to native cadherin-like receptor emphasizes the importance of this receptor class for Bt toxin research

Effectiveness of need measurement in identifying student change in a university

Call number: LD2668 .T4 1967 J4Master of Scienc

Rising top-income persistence in Australia: evidence from income tax data

We use a new Australian longitudinal income tax dataset, Alife, covering 1991–2017, to examine levels and trends in the persistence in top-income group membership, focussing on the top 1%. We summarize persistence in multiple ways, documenting levels and trends in rates of remaining in top-income groups; re-entry to the top; the income changes associated with top-income transitions; and we also compare top-income persistence rates for annual and ‘permanent’ incomes. Regardless of the perspective taken, top-income persistence increased markedly over the period, with most of the increase occurring in the mid-2000s and early 2010s. In the mid- to late2010s, Australian top-income persistence rates appear to have been near the top of the range of tax-data estimates for other countries. Using univariate breakdowns and multivariate regression, we show that the rise in top-income persistence in Australia was experienced by many population subgroups

Hybrid High-Order Finite Volume/Discontinuous Galerkin Methods for Turbulent Flows

In this paper we develop a family of arbitrarily high-order non-oscillatory hybrid Finite Volume/Discontinuous Galerkin schemes for turbulent flows on mixed-element unstructured meshes. The schemes are inherently compact in the sense that the central stencils employed are as compact as possible, and that the directional stencils are reduced in size, simplifying their implementation. Their key ingredient is the switch between a DG method and a FV method based on the CWENOZ scheme when a troubled cell is detected. Therefore, in smooth regions of the computational domain, the high order of accuracy offered by DG is preserved, while in regions with sharp gradients, the robustness of FV is utilized. This paper also presents the time evolution of troubled cells in unsteady test cases and the use of extended bounds for troubled cell detection. We assess the performance of these schemes in terms of accuracy, robustness and computational cost through a series of stringent 2D and 3D test problems. The results obtained demonstrate the accuracy and robustness that the schemes offer and highlight areas of future improvements that are considered

Seeing the smart city on Twitter: Colour and the affective territories of becoming smart

This paper pays attention to the immense and febrile field of digital image files which picture the smart city as they circulate on the social media platform Twitter. The paper considers tweeted images as an affective field in which flow and colour are especially generative. This luminescent field is territorialised into different, emergent forms of becoming ‘smart’. The paper identifies these territorialisations in two ways: firstly, by using the data visualisation software ImagePlot to create a visualisation of 9030 tweeted images related to smart cities; and secondly, by responding to the affective pushes of the image files thus visualised. It identifies two colours and three ways of affectively becoming smart: participating in smart, learning about smart, and anticipating smart, which are enacted with different distributions of mostly orange and blue images. The paper thus argues that debates about the power relations embedded in the smart city should consider the particular affective enactment of being smart that happens via social media. More generally, the paper concludes that geographers must pay more attention to the diverse and productive vitalities of social media platforms in urban life and that this will require experiment with methods that are responsive to specific digital qualities

Blocking binding of Bacillus thuringiensis Cry1Aa to Bombyx mori cadherin receptor results in only a minor reduction of toxicity

<p>Abstract</p> <p>Background</p> <p><it>Bacillus thuringiensis </it>Cry1Aa insecticidal protein is the most active known <it>B. thuringiensis </it>toxin against the forest insect pest <it>Lymantria dispar </it>(gypsy moth), unfortunately it is also highly toxic against the non-target insect <it>Bombyx mori </it>(silk worm).</p> <p>Results</p> <p>Surface exposed hydrophobic residues over domains II and III were targeted for site-directed mutagenesis. Substitution of a phenylalanine residue (F328) by alanine reduced binding to the <it>Bombyx mori </it>cadherin by 23-fold, reduced biological activity against <it>B. mori </it>by 4-fold, while retaining activity against <it>Lymantria dispar</it>.</p> <p>Conclusion</p> <p>The results identify a novel receptor-binding epitope and demonstrate that virtual elimination of binding to cadherin BR-175 does not completely remove toxicity in the case of <it>B. mori</it>.</p

Entomology research in southeast Missouri 1960.

Cover title.This report summarized research on crop pest control conducted by the Agricultural Experiment Station in southeast Missouri during 1960.Cotton insect research / Keith Harrendorf -- Corn insects / Armon J. Keaster, Mahlon L. Fairchild, B. Dean Barry -- Nematode control / Lee Jenkins