Navigating Identity: The Intersection of Social and Biological Identity from the WWII Battle of Tarawa

The 1943 Battle of Tarawa resulted in the loss of approximately 1000 U.S. service members on or around Betio Island, Tarawa Atoll, Republic of Kiribati. Nearly half the casualties were accounted for following the battle. The Defense POW/MIA Accounting Agency (DPAA) has worked to identify the remaining ~510 unaccounted-for service members, with successful identification of ~160 service members to date. Demographic data pulled from historical documentation of the U.S. losses indicate a relatively homogeneous population (99% White, 81% between the ages of 17 to 23 years, and only two individuals documented with a religious preference other than Protestant or Catholic). Using this demographic data as a framework, three case studies are presented to demonstrate how a holistic biosocial approach to identity building could facilitate forensic identifications. The temporal and sociocultural contextualization of analyses enables anthropologists to navigate the inconsistencies between 21st century and historical (1940s) social identity concepts and overcome challenges to identification. The case studies demonstrate how biological evidence, genetic evidence, and material culture (material evidence) differently contribute to the social identity of an individual and can impact identification efforts when analytical conclusions are incongruent with historical documentation. The first case examines how morphometric biological affinity assessments are biased by the fluidity of social identity concepts when complex morphological and metric indicators of biological affinity are not represented in the historical race categories for the U.S. Battle of Tarawa casualties. The second case demonstrates how biogeographic genetic affinity predictions, through a discussion of the G2a4 haplogroup, need to be examined holistically in the context of other lines of evidence. The third case highlights how material evidence can further define social identity beyond physicality, genetic structure, and race. The challenges of interpreting identity from human remains, as highlighted through these examples, are common among anthropologists working in disaster victim identification and other humanitarian contexts. Thus, it is imperative for anthropologists to be self-aware of implicit biases toward the current prevailing definitions of biological and social identity and to consider historical perceptions of identity when working in these contexts

Systematic analysis of phosphotyrosine antibodies recognizing single phosphorylated EPIYA-motifs in CagA of East Asian-type Helicobacter pylori strains

BACKGROUND: Highly virulent strains of the gastric pathogen Helicobacter pylori encode a type IV secretion system (T4SS) that delivers the effector protein CagA into gastric epithelial cells. Translocated CagA undergoes tyrosine phosphorylation by members of the oncogenic c-Src and c-Abl host kinases at EPIYA-sequence motifs A, B and D in East Asian-type strains. These phosphorylated EPIYA-motifs serve as recognition sites for various SH2-domains containing human proteins, mediating interactions of CagA with host signaling factors to manipulate signal transduction pathways. Recognition of phospho-CagA is mainly based on the use of commercial pan-phosphotyrosine antibodies that were originally designed to detect phosphotyrosines in mammalian proteins. Specific anti-phospho-EPIYA antibodies for each of the three sites in CagA are not forthcoming. RESULTS: This study was designed to systematically analyze the detection preferences of each phosphorylated East Asian CagA EPIYA-motif by pan-phosphotyrosine antibodies and to determine a minimal recognition sequence. We synthesized phospho- and non-phosphopeptides derived from each predominant EPIYA-site, and determined the recognition patterns by seven different pan-phosphotyrosine antibodies using Western blotting, and also investigated representative East Asian H. pylori isolates during infection. The results indicate that a total of only 9–11 amino acids containing the phosphorylated East Asian EPIYA-types are required and sufficient to detect the phosphopeptides with high specificity. However, the sequence recognition by the different antibodies was found to bear high variability. From the seven antibodies used, only four recognized all three phosphorylated EPIYA-motifs A, B and D similarly well. Two of the phosphotyrosine antibodies preferentially bound primarily to the phosphorylated motif A and D, while the seventh antibody failed to react with any of the phosphorylated EPIYA-motifs. Control experiments confirmed that none of the antibodies reacted with non-phospho-CagA peptides and in accordance were able to recognize phosphotyrosine proteins in human cells. CONCLUSIONS: The results of this study disclose the various binding preferences of commercial anti-phosphotyrosine antibodies for phospho-EPIYA-motifs, and are valuable in the application for further characterization of CagA phosphorylation events during infection with H. pylori and risk prediction for gastric disease development