Interaction of Insulin-Like Growth Factor-Binding Protein 2 with α2-Macroglobulin in the Circulation

Insulin-like growth factors (IGFs) play active role in mitogenic and metabolic processes. In the peripheral circulation, they are mostly bound to specific IGF-binding proteins (IGFBPs). Proteolysis of IGFBPs releases free, active IGFs. IGFBP-2 is the second most abundant of the six binding proteins and its concentration increases in catabolic states. The possible interaction between IGFBP-2 and other proteins in the circulation was investigated in this study. Our results showed that IGFBP-2 associates with α2-macroglobulin (α2M), a protease inhibitor. Formation of IGFBP-2/α2M complexes most likely contributes to the regulation of IGFBP-2 proteolysis and, thus, the activity of IGFs.     

Diversity and evolution of the highly polymorphic tandem repeat LEI0258 in the chicken MHC-B region

The chicken major histocompatibility complex (MHC) is located on the microchromosome 16 and is described as the most variable region in the genome. The genes of the MHC play a central role in the immune system. Particularly, genes encoding proteins involved in the antigen presentation to T cells. Therefore, describing the genetic polymorphism of this region is crucial in understanding host–pathogen interactions. The tandem repeat LEI0258 is located within the core area of the B region of the chicken MHC (MHC-B region) and its genotypes correlate with serology. This marker was used to provide a picture of the worldwide diversity of the chicken MHC-B region and to categorize chicken MHC haplotypes. More than 1,600 animals from 80 different populations or lines of chickens from Africa, Asia, and Europe, including wild fowl species, were genotyped at the LEI0258 locus. Fifty novel alleles were described after sequencing. The resulting 79 alleles were classified into 12 clusters, based on the SNPs and indels found within the sequences flanking the repeats. Furthermore, hypotheses were formulated on the evolutionary dynamics of the region. This study constitutes the largest variability report for the chicken MHC and establishes a framework for future diversity or association studies.     

The YUMM lines: a series of congenic mouse melanoma cell lines with defined genetic alterations

The remarkable success of immune therapies emphasizes the need for immune‐competent cancer models. Elegant genetically engineered mouse models of a variety of cancers have been established, but their effective use is limited by cost and difficulties in rapidly generating experimental data. Some mouse cancer cell lines are transplantable to immunocompetent host mice and have been utilized extensively to study cancer immunology. Here, we describe the Yale University Mouse Melanoma (YUMM) lines, a comprehensive system of mouse melanoma cell lines that are syngeneic to C57BL/6, have well‐defined human‐relevant driver mutations, and are genomically stable. This will be a useful tool for the study of tumor immunology and genotype‐specific cancer biology.     

Improving Education in Medical Statistics: Implementing a Blended Learning Model in the Existing Curriculum

Background

Although recent studies report on the benefits of blended learning in improving medical student education, there is still no empirical evidence on the relative effectiveness of blended over traditional learning approaches in medical statistics. We implemented blended along with on-site (i.e. face-to-face) learning to further assess the potential value of web-based learning in medical statistics.

Methods

This was a prospective study conducted with third year medical undergraduate students attending the Faculty of Medicine, University of Belgrade, who passed (440 of 545) the final exam of the obligatory introductory statistics course during 2013–14. Student statistics achievements were stratified based on the two methods of education delivery: blended learning and on-site learning. Blended learning included a combination of face-to-face and distance learning methodologies integrated into a single course.

Results

Mean exam scores for the blended learning student group were higher than for the on-site student group for both final statistics score (89.36±6.60 vs. 86.06±8.48; p = 0.001) and knowledge test score (7.88±1.30 vs. 7.51±1.36; p = 0.023) with a medium effect size. There were no differences in sex or study duration between the groups. Current grade point average (GPA) was higher in the blended group. In a multivariable regression model, current GPA and knowledge test scores were associated with the final statistics score after adjusting for study duration and learning modality (p<0.001).

Conclusion

This study provides empirical evidence to support educator decisions to implement different learning environments for teaching medical statistics to undergraduate medical students. Blended and on-site training formats led to similar knowledge acquisition; however, students with higher GPA preferred the technology assisted learning format. Implementation of blended learning approaches can be considered an attractive, cost-effective, and efficient alternative to traditional classroom training in medical statistics.     

Single-step method for β-galactosidase assays in Escherichia coli using a 96-well microplate reader

Historically, the lacZ gene is one of the most universally used reporters of gene expression in molecular biology. Its activity can be quantified using an artificial substrate, o-nitrophenyl-ß-d-galactopyranoside (ONPG). However, the traditional method for measuring LacZ activity (first described by J. H. Miller in 1972) can be challenging for a large number of samples, is prone to variability, and involves hazardous compounds for lysis (e.g., chloroform, toluene).     

Predicting the success of an invader: Niche shift versus niche conservatism

Invasive species can encounter environments different from their source populations, which may trigger rapid adaptive changes after introduction (niche shift hypothesis). To test this hypothesis, we investigated whether postintroduction evolution is correlated with contrasting environmental conditions between the European invasive and source ranges in the Asian tiger mosquito Aedes albopictus. The comparison of environmental niches occupied in European and source population ranges revealed more than 96% overlap between invasive and source niches, supporting niche conservatism. However, we found evidence for postintroduction genetic evolution by reanalyzing a published ddRADseq genomic dataset from 90 European invasive populations using genotype–environment association (GEA) methods and generalized dissimilarity modeling (GDM). Three loci, among which a putative heat‐shock protein, exhibited significant allelic turnover along the gradient of winter precipitation that could be associated with ongoing range expansion. Wing morphometric traits weakly correlated with environmental gradients within Europe, but wing size differed between invasive and source populations located in different climatic areas. Niche similarities between source and invasive ranges might have facilitated the establishment of populations. Nonetheless, we found evidence for environmental‐induced adaptive changes after introduction. The ability to rapidly evolve observed in invasive populations (genetic shift) together with a large proportion of unfilled potential suitable areas (80%) pave the way to further spread of Ae. albopictus in Europe.     

Titanium dioxide as a chemo-affinity solid phase in offline phosphopeptide chromatography prior to HPLC-MS/MS analysis

We have developed a new offline chromatographic approach for the selective enrichment of phosphorylated peptides that is directly compatible with subsequent analysis by online nano electrospray ionization tandem mass spectrometry. In this technique, a titanium dioxide (TiO2)-packed pipette tip is used as a phosphopeptide trap that acts as an offline first-dimension separation step in a two-dimensional chromatography system. This is followed by online nano reversed-phase high-performance liquid chromatography. Here, we present suitable methods for enrichment, optimized separately for each step: sample loading, washing and elution from the TiO2-filled tips. To increase the trapping selectivity of the TiO2 column, we used the sodium salt of 1-octanesulfonic acid combined with 2,5-dihydroxybenzoic acid as ion-pairing agents and displacers for acidic peptides. These agents also improve the binding of phosphorylated peptides and block the binding of non-phosphorylated ones. This enrichment procedure takes 30 min, followed by a 100-min HPLC program, including washing and an elution gradient.