Scientific Discrimination and the Activist Scientist: L.C. Dunn and the Professionalization of Genetics and Human Genetics in the United States

During the 1920s and 1930s geneticist L.C. Dunn of Columbia University cautioned Americans against endorsing eugenic policies and called attention to eugenicists’ less than rigorous practices. Then, from the mid-1940s to early 1950s he attacked scientific racism and Nazi Rassenhygiene by co-authoring Heredity, Race and Society with Theodosius Dobzhansky and collaborating with members of UNESCO (United Nations Educational, Scientific, and Cultural Organization) on their international campaign against racism. Even though shaking the foundations of scientific discrimination was Dunn’s primary concern during the interwar and post-World War II years, his campaigns had ancillary consequences for the discipline. He contributed to the professionalization of genetics during the 1920s and 1930s and sought respectability for human genetics in the 1940s and 1950s. My article aims to elucidate the activist scientist’s role in undermining scientific discrimination by exploring aspects of Dunn’s scientific work and political activism from the 1920s to 1950s. Definitions are provided for scientific discrimination and activist scientist.     

Consequences of concurrent Ascaridia galli and Escherichia coli infections in chickens

   

Three experiments were carried out to examine the consequences of concurrent infections with Ascaridia galli and Escherichia coli in chickens raised for table egg production. Characteristic pathological lesions including airsacculitis, peritonitis and/or polyserositis were seen in all groups infected with E. coli. Furthermore, a trend for increased mortality rates was observed in groups infected with both organisms which, however, could not be confirmed statistically. The mean worm burden was significantly lower in combined infection groups compared to groups infected only with A. galli. It was also shown that combined infections of E. coli and A. galli had an added significant negative impact on weight gain.     

The evolutionary radiation of Arvicolinae rodents (voles and lemmings): relative contribution of nuclear and mitochondrial DNA phylogenies

Background  

Mitochondrial and nuclear genes have generally been employed for different purposes in molecular systematics, the former to resolve relationships within recently evolved groups and the latter to investigate phylogenies at a deeper level. In the case of rapid and recent evolutionary radiations, mitochondrial genes like cytochrome b (CYB) are often inefficient for resolving phylogenetic relationships. One of the best examples is illustrated by Arvicolinae rodents (Rodentia; Muridae), the most impressive mammalian radiation of the Northern Hemisphere which produced voles, lemmings and muskrats. Here, we compare the relative contribution of a nuclear marker – the exon 10 of the growth hormone receptor (GHR) gene – to the one of the mitochondrial CYB for inferring phylogenetic relationships among the major lineages of arvicoline rodents.     

The effect of methylprednisolone on cytokine concentration and leukocyte adhesion molecule expression in an isolated cardiopulmonary bypass system

This study examines the effect of methylprednisolone on cytokine balance and adhesion molecule expression within an isolated cardiopulmonary bypass (CPB) system. This isolated CPB system is an in vitro model which simulates the pro-inflammatory immune response. Whole blood from 10 volunteers was obtained in two equal amounts. Heparin and saline were added to the control group while heparin and methylprednisolone were added to the methylprednisolone group. The blood was added to two identical CPB circuits and bypass commenced by a trained perfusionist. Samples were taken at blood donation (Sample 0), 10 min after the addition of drugs (Sample 1) and after 30, 60 and 90 min of CPB (Samples 2, 3 and 4, respectively). Cytokines interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-1 receptor antagonist (IL-1ra) and tumour necrosis factor soluble receptor 2 (TNFsr2) and the leucocyte adhesion molecules L-selectin, HLA DR, CD18 and CD11b were determined. IL-8 increased in both groups. This increase was significantly less in the methylprednisolone group. Increases in granulocyte CD11b and CD18 expression were less in the methylprednisolone group than in the control group but did not reach statistical significance. These results indicate that methylprednisolone significantly reduces the production of IL-8 in an isolated CPB system. This effect occurs in the absence of IL-10.     

The abundance of additional N-acetyllactosamine units in N-linked tetraantennary oligosaccharides of human Tamm-Horsfall glycoprotein is a donor-specific feature

Previously, treatment of Tamm-Horsfall glycoprotein (THp) from different donors with endo-beta-galactosidase has been shown to liberate a tetra- and a Sd(a)-active pentasaccharide, concluding the presence of N-linked carbohydrate chains containing additional N - acetyllactosamine units. These type of oligosaccharides were not found in a detailed structure elucidation of the carbohydrate moiety of THp of one male donor, suggesting a donor-specific feature for these type of structures. Therefore, THp was isolated from four healthy male donors and each subjected to endo-beta-galactosidase treatment in order to release these tetra- and Sd(a)-active pentasaccharide. Differences were observed in the total amount of released tetra- and Sda-active pentasaccharide of the used donors (42, 470, 478, 718 microg/100 mg THp), indicating that the presence of repeating N-acetyllactosamine units incorporated into the N-glycan moiety of THp is donor specific. Furthermore, a higher expression of the Sd(a) determinant on antennae which display N-acetyllactosamine elongation was observed, suggesting a better accessibility for the beta-N-acetylgalactosaminyltransferase. In order to characterize the N-glycans containing repeating N- acetyllactosamine units, carbohydrate chains were enzymatically released from THp and isolated. The tetraantennary fraction, which accounts for more than 33% of the total carbohydrate moiety of THp, was used to isolate oligosaccharides containing additional N - acetyllactosamine units. Five N-linked tetraantennary oligosaccharides containing a repeating N-acetyllactosamine unit were identified, varying from structures bearing four Sd(a) determinants to structures containing no Sd(a) determinant (see below). One compound was used in order to specify the branch location of the additional N- acetyllactosamine unit, and it appeared that only the Gal-6' and Gal-8' residues were occupied by a repeating N -acetyllactosamine unit.      

Differential binding of lectins IL-2 and CSL to candida albicans and cancer cells

The demonstration that interleukin 2 (IL-2) is a lectin specific for oligomannosides allows to understand a new function for this cytokine: as a bifunctional molecule when bound to its receptor ss, IL-2 associates the latter which the CD3/TCR complex, interacting with oligosaccharides of CD3 through its carbohydrate-recognition domain (Zanetta et al. , 1996, Biochem. J., 318, 49-53). This induces the tyrosine phosphorylation of the IL-2R beta by ++p56(lck) , the first step of the IL-2-dependent signaling. Since this specific association is disrupted in vitro by oligomannosides with five and six mannose residues, we made the hypothesis that pathogenic cells or microorganisms could bind IL-2, consequently disturbing the IL-2- dependent response. This study shows that the pathogenic yeast Candida albicans (in contrast with nonpathogenic yeasts) binds high amounts of IL-2 as did cancer cells. In contrast with cancer cells, yeasts do not bind the Man6GlcNAc2-specific lectin CSL, an endogenous "amplifier of activation signals" (Zanetta et al. , 1995, Biochem. J., 311, 629-636).