Nanobody-Based Probes for Subcellular Protein Identification and Visualization

Understanding how building blocks of life contribute to physiology is greatly aided by protein identification and cellular localization. The two main labeling approaches developed over the past decades are labeling with antibodies such as immunoglobulin G (IgGs) or use of genetically encoded tags such as fluorescent proteins. However, IgGs are large proteins (150 kDa), which limits penetration depth and uncertainty of target position caused by up to ∼25 nm distance of the label created by the chosen targeting approach. Additionally, IgGs cannot be easily recombinantly modulated and engineered as part of fusion proteins because they consist of multiple independent translated chains. In the last decade single domain antigen binding proteins are being explored in bioscience as a tool in revealing molecular identity and localization to overcome limitations by IgGs. These nanobodies have several potential benefits over routine applications. Because of their small size (15 kDa), nanobodies better penetrate during labeling procedures and improve resolution. Moreover, nanobodies cDNA can easily be fused with other cDNA. Multidomain proteins can thus be easily engineered consisting of domains for targeting (nanobodies) and visualization by fluorescence microscopy (fluorescent proteins) or electron microscopy (based on certain enzymes). Additional modules for e.g., purification are also easily added. These nanobody-based probes can be applied in cells for live-cell endogenous protein detection or may be purified prior to use on molecules, cells or tissues. Here, we present the current state of nanobody-based probes and their implementation in microscopy, including pitfalls and potential future opportunities

High-speed rail studies in South Africa

Papers presented virtually at the 41st International Southern African Transport Conference on 10-13 July 2023.The presentation covers the Limpopo to Gauteng high-speed rail and Moloto corridor

Neurotensin, vaso-active intestinal polypeptide and gastrin levels in plasma and portal venous blood in experimental mesenteric ischaemia

The effect of mesenteric ischaemia on the levels of neurotensin, vaso-active intestinal polypeptide and gastrin in portal venous blood and in the peripheral circulation was studied in two groups of 7 and 6 baboons (Papio ursinus). In peripheral blood a decreasing trend in levels of neurotensin was observed, while vaso-active intestinal polypeptide and gastrin levels were unchanged. There was a similar trend in neurotensin levels in portal venous blood, together with an increasing trend in levels of vaso-active intestinal polypeptide. Gastrin levels were unchanged. Further investigation of these apparent trends in a larger number of animals is warranted

The reliability of mortality data in Johannesburg

Infonnation on deaths in Johannesburg is collected on a voluntary basis by the Johannesburg City Health Department from the Department of Home Affairs regional offices as well as state mortuaries in the area. The reliability of these routinely collected data was assessed. Records of deaths of Asians, coloureds and whites from 1 July 1989 to 31 December 1989 were included in the study. Burial orders obtained from the different cemeteries and crematoria in the area were compared with the routinely collected mortality data. Two thousand eight hundred and thirty-seven deaths were included in the study. One hundred and ninety (6%) deaths in the department's records could not be found among the corresponding burial orders while 1 019 (36%) burial order records were not found among the department's routinely collected mortality data. Underreporting of deaths was greatest among the aged (43%) and infants (39%). When this underreporting was taken into account, the corrected infant mortality rate was 19,111 000 live births as opposed to 14,1. Recommendations are made for the improvement ofthe quality of routinely collected mortality data

Reply to the comment A.J. Kassman and D.B. Losee on the "Effect of gallium ions and of preparation methods on the structural properties of cobalt-molybdenum-alumina catalysts"

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A comparative study of numerical approximations for solving the Smoluchowski coagulation equation

In this work, numerical approximations for solving the one dimensional Smoluchowski coagulation equation on non-uniform meshes has been analyzed. Among the various available numerical methods, finite volume and sectional methods have explicit advantage such as mass conservation and an accurate prediction of different order moments. Here, a recently developed efficient finite volume scheme (Singh et al., 2015) and the cell average technique (Kumar et al., 2006) are compared. The numerical comparison is established for both analytically tractable as well as physically relevant kernels. It is concluded that the finite volume scheme predicts both number density as well as different order moments with higher accuracy than the cell average technique. Moreover, the finite volume scheme is computationally less expensive than the cell average technique

Beyond persons: extending the personal / subpersonal distinction to non-rational animals and artificial agents

The distinction between personal level explanations and subpersonal ones has been subject to much debate in philosophy. We understand it as one between explanations that focus on an agent’s interaction with its environment, and explanations that focus on the physical or computational enabling conditions of such an interaction. The distinction, understood this way, is necessary for a complete account of any agent, rational or not, biological or artificial. In particular, we review some recent research in Artificial Life that pretends to do completely without the distinction, while using agent-centered concepts all the way. It is argued that the rejection of agent level explanations in favour of mechanistic ones is due to an unmotivated need to choose among representationalism and eliminativism. The dilemma is a false one if the possibility of a radical form of externalism is considered