Does the Segregation of Evolution in Biology Textbooks and Introductory Courses Reinforce Students’ Faulty Mental Models of Biology and Evolution?

The well-established finding that substantial confusion and misconceptions about evolution and natural selection persist after college instruction suggests that these courses neither foster accurate mental models of evolution’s mechanisms nor instill an appreciation of evolution’s centrality to an understanding of the living world. Our essay explores the roles that introductory biology courses and textbooks may play in reinforcing undergraduates’ pre-existing, faulty mental models of the place of evolution in the biological sciences. Our content analyses of the three best-selling introductory biology textbooks for majors revealed the conceptual segregation of evolutionary information. The vast majority of the evolutionary terms and concepts in each book were isolated in sections about evolution and diversity, while remarkably few were employed in other sections of the books. Standardizing the data by number of pages per unit did not alter this pattern. Students may fail to grasp that evolution is the unifying theme of biology because introductory courses and textbooks reinforce such isolation. Two goals are central to resolving this problem: the desegregation of evolution as separate “units” or chapters and the active integration of evolutionary concepts at all levels and across all domains of introductory biology.     

PDL1 Expression on Plasma and Dendritic Cells in Myeloma Bone Marrow Suggests Benefit of Targeted anti PD1-PDL1 Therapy

In this study we set out to investigate whether anti PDL1 or PD–1 treatment targeting the immune system could be used against multiple myeloma. DCs are important in regulating T cell responses against tumors. We therefore determined PDL1 and PDL2 expression on DC populations in bone marrow of patients with plasma cell disorders using multicolour Flow Cytometry. We specifically looked at CD141⁺ and CD141^- myeloid and CD303⁺ plasmacytoid DC. The majority of plasma cells (PC) and DC subpopulations expressed PDL1, but the proportion of positive PDL1+ cells varied among patients. A correlation between the proportion of PDL1⁺ PC and CD141⁺ mDC was found, suggesting both cell types could down-regulate the anti-tumor T cell response.     

From left to right all through the night: Characteristics of lying rest in zoo elephants

Despite increased research during the past years, many characteristics of resting behavior in elephants are still unknown. For example, there is only limited data suggesting elephants express longer lying bouts and increased total nightly lying durations on soft substrates as compared to hard surfaces. Additionally, it has not been investigated how frequently elephants change body sides between lying bouts. Here we present these characteristics based on observations of nighttime lying behavior in 10 zoo elephants (5 African Loxodonta africana and 5 Asian Elephas maximus elephants) living in five different European facilities. We found that elephants housed on soft substrates have significantly increased total lying durations per night and longer average lying bouts. Furthermore, at 70%−85% of all bouts, a consistently higher frequency of side change between lying bouts occurred on soft substrates, leading to an overall equal laterality in resting behavior. Deviations from this pattern became evident in elephants living on nonsand flooring or/and in nondominant individuals of nonfamily groups, respectively. Based on our findings, we consider elephants to normally have several lying bouts per night with frequent side changes, given an appropriate substrate and healthy social environment. We encourage elephant-keeping facilities to monitor these characteristics in their elephants' nighttime behavior to determine opportunities for further improvements and detect alterations putatively indicating social or health problems in individual elephants at an early stage.     

Evaluation of surfactants as solubilizing agents in microsomal metabolism reactions with lipophilic substrates

Solubilizing agents are routinely added when investigating the biotransformation of lipophilic substrates using hepatic microsomes. For highly lipophilic compounds, the concentration of solvent or surfactant necessary for dissolution can be detrimental to enzyme activity. This study evaluates the effect of 12 surfactants on microsomal metabolism and the ability of the same surfactants to improve the aqueous solubility of the pentabrominated diphenyl ether BDE-100, a lipophilic environmental contaminant previously found to be recalcitrant to in vitro metabolism. Of the surfactants investigated, Cremophor EL and Tween 80 displayed the best combination of increased BDE-100 solubility and minimal inhibition of microsomal metabolism. However, a comparison of the in vitro metabolism products of BDE-100 in the presence of the two surfactants revealed varying amounts of metabolites depending on the surfactant used.     

Improved Protein-A separation of VH3 Fab from Fc after Papain Digestion of Antibodies

Antibody-binding fragments (Fab) are generated from whole antibodies by treatment with papain and can be separated from the Fc component using Protein-A affinity chromatography. Commercial kits are available, which facilitate the production and purification of Fab fragments; however, the manufacturer fails to report that this method is inefficient for antibodies with V_H3 domains as a result of the intrinsic variable region affinity for Protein-A. A commercially available, modified Protein-A resin (MabSelect SuRe) has been engineered for greater stability. Here, we report that an additional consequence of the modified resin is the ability to purify V_H3 family Fab fragments, which cannot be separated effectively from other components of the papain digest by traditional Protein-A resin. This improvement of a commonly used procedure is of significance, as increasingly, therapeutic antibodies are being derived from human origin, where V_H3 is the most abundantly used variable region family.     

Transport of quinolinic acid into rabbit and rat brain

The transport metabolism of [³H]quinolinic acid in the central nervous system of rabbits and rats were studied. In vitro [³H]quinolinic acid was not readily accumulated by isolated choroid plexus. After the intraventricular injection of tracer quantities of [³H]quinolinic acid, the [³H]quinolinic acid did not enter the brain as readily as concurrently injected [¹⁴C]mannitol and was not metabolized, The permeability-surface area constant for [³H]quinolinic acid at the rat blood-brain barrier was 1.5±1.3×10^–5 sec^–1 compared to 2.8±0.4×10^–5 sec^–1 for [³H]mannitol. Our results suggest that: 1) [³H]quinolinic acid is transported in the CNS by passive diffusion and 2) is not metabolized.     

Cellular Expression, Developmental Regulation, and Phylogenic Conservation of PEA-15, the Astrocytic Major Phosphoprotein and Protein Kinase C Substrate

Abstract: PEA-15 has recently been identified as a major phosphoprotein in astrocytes and an endogenous substrate for protein kinase C. This 15-kDa protein exists under three molecular forms, an unphosphorylated form, N, and two phosphorylated forms, Pa and Pb. ntisera were raised against synthetic peptides corresponding to the internal sequences of the mouse protein containing the two specific phosphorylation sites and affinity-purified antibodies were used for immunoblotting. PEA-15 was found mainly in the cytosol, but its protein kinase C-phosphorylated form, Pb, was also detectable in association with the membrane and remained with the fraction that contains stabilized microtubules. Abundant in astrocytes, particularly in the hippocampus, PEA-15 was also detected in all cultured brain cell types examined, indicating a more ubiquitous distribution of the protein, further demonstrated by its detection in the eye and in the lung. Parallel to the increase in expression levels, phosphorylation of PEA-15 also increased during development. This paralleled results obtained in primary cultures, where PEA-15 levels increase with cell maturation. Finally, physiological importance of PEA-15 phosphorylation was illustrated by immunoreactivity observed in brain homogenates of different mammals, birds, amphibians, and fish.