Transposing from the laboratory to the classroom to generate authentic research experiences for undergraduates.

Large lecture classes and standardized laboratory exercises are characteristic of introductory biology courses. Previous research has found that these courses do not adequately convey the process of scientific research and the excitement of discovery. Here we propose a model that provides beginning biology students with an inquiry-based, active learning laboratory experience. The Dynamic Genome course replicates a modern research laboratory focused on eukaryotic transposable elements where beginning undergraduates learn key genetics concepts, experimental design, and molecular biological skills. Here we report on two key features of the course, a didactic module and the capstone original research project. The module is a modified version of a published experiment where students experience how virtual transposable elements from rice (Oryza sativa) are assayed for function in transgenic Arabidopsis thaliana. As part of the module, students analyze the phenotypes and genotypes of transgenic plants to determine the requirements for transposition. After mastering the skills and concepts, students participate in an authentic research project where they use computational analysis and PCR to detect transposable element insertion site polymorphism in a panel of diverse maize strains. As a consequence of their engagement in this course, students report large gains in their ability to understand the nature of research and demonstrate that they can apply that knowledge to independent research projects

Pressure test analysis of 200-inch multicell test tank

Pressure test analysis for large multiple cell tank with sectioned ski

“It will always continue unless we can change something”: consequences of intimate partner violence for indigenous women, children, and families

Background: Violence against indigenous women and girls is endemic, yet the absence of research on the consequences of this violence from the perspectives of women presents a profound barrier to the development of knowledge, along with violence prevention and mitigation. Although family is central to many indigenous communities, existing research typically examines the consequences of intimate partner violence (IPV) on women or children in isolation, rather than examining its consequences holistically. Objective: The purpose of this article is to identify US indigenous women's perspectives about the impact of IPV on women, children, and families. Method: Data were collected with 29 indigenous women affected by violence from a Southeastern tribe in the United States. As part of a larger critical ethnography, pragmatic horizon analysis of life history interviews revealed the consequences of IPV across multiple levels. Results: Women reported profound psychological consequences resulting from IPV. The majority of women had witnessed IPV in their childhood, providing support for an intergenerational cycle of violence. Women reported psychological consequences on children, which paralleled those reported by women, leaving deep impressions on children across their life course. Consequences on children and whole families were extensive, indicating the negative ramifications of IPV transcended personal boundaries and affected children and families across multiple generations. Conclusions: Given the tight-knit nature of indigenous families and communities, the consequences across individuals and families were noteworthy. However, a dearth in research examining consequences of IPV across levels fails to capture the interconnections of consequences for women, children, and families. Given the centrality of family in many indigenous communities, examining IPV from a holistic perspective that incorporates multiple levels is recommended for IPV research and intervention development

Immunological characterization of chromogranins A and B and secretogranin II in the bovine pancreatic islet

Antisera against chromogranin A and B and secretogranin II were used for analysing the bovine pancreas by immunoblotting and immunohistochemistry. All three antigens were found in extracts of fetal pancreas by one dimensional immunoblotting. A comparison with the soluble proteins of chromaffin granules revealed that in adrenal medulla and in pancreas antigens which migrated identically in electrophoresis were present. In immunohistochemistry, chromogranin A was found in all pancreatic endocrine cell types with the exception of most pancreatic polypeptide-(PP-) producing cells. For chromogranin B, only a faint immunostaining was obtained. For secretorgranin II, A-and B-cells were faintly positive, whereas the majority of PP-cells exhibited a strong immunostaining for this antigen. These results establish that chromogranins A and B and secretogranin II are present in the endocrine pancreas, but that they exhibit a distinct cellular localization

Limitations of Absolute Current Densities Derived from the Semel & Skumanich Method

Semel and Skumanich proposed a method to obtain the absolute electric current density, |Jz|, without disambiguation of 180 degree in the transverse field directions. The advantage of the method is that the uncertainty in the determination of the ambiguity in the magnetic azimuth is removed. Here, we investigate the limits of the calculation when applied to a numerical MHD model. We found that the combination of changes in the magnetic azimuth with vanishing horizontal field component leads to errors, where electric current densities are often strong. Where errors occur, the calculation gives |Jz| too small by factors typically 1.2 ~ 2.0.Comment: 10 pages, 4 figures. To appear on Science in China Series G: Physics, Mechanics & Astronomy, October 200

Import of cytochrome c into mitochondria

The import of cytochrome c into mitochondria can be resolved into a number of discrete steps. Here we report on the covalent attachment of heme to apocytochrome c by the enzyme cytochrome c heme lyase in mitochondria from Neurospora crassa. A new method was developed to measure directly the linkage of heme to apocytochrome c. This method is independent of conformational changes in the protein accompanying heme attachment. Tryptic peptides of [35S]cysteine-labelled apocytochrome c, and of enzymatically formed holocytochrome c, were resolved by reverse-phase HPLC. The cysteine-containing peptide to which heme was attached eluted later than the corresponding peptide from apocytochrome c and could be quantified by counting 35S radioactivity as a measure of holocytochrome c formation. Using this procedure, the covalent attachment of heme to apocytochrome c, which is dependent on the enzyme cytochrome c heme lyase, could be measured. Activity required heme (as hemin) and could be reversibly inhibited by the analogue deuterohemin. Holocytochrome c formation was stimulated 5–10-fold by NADH > NADPH > glutathione and was independent of a potential across the inner mitochondrial membrane. NADH was not required for the binding of apocytochrome c to mitochondria and was not involved in the reduction of the cysteine thiols prior to heme attachment. Holocytochrome c formation was also dependent on a cytosolic factor that was necessary for the heme attaching step of cytochrome c import. The factor was a heat-stable, protease-insensitive, low-molecular-mass component of unknown function. Cytochrome c heme lyase appeared to be a soluble protein located in the mitochondrial intermembrane space and was distinct from the previously identified apocytochrome c binding protein having a similar location. A model is presented in which the covalent attachment of heme by cytochrome c heme lyase also plays an essential role in the import pathway of cytochrome c

Group Processes

Social behavior is often group behavior. People are in many respects individuals seeking their personal, private objectives, yet they are also members of social collectives that bind members to one another. The tendency to join with others is perhaps the most important single characteristic of humans. The processes that take place within these groups influence, in fundamental ways, their members and society-at-large. Just as the dynamic processes that occur in groups--such as the exchange of information among members, leading and following, pressures put on members to adhere to the group\u27s standards, shifts in friendship alliances, and conflict and collaboration-change the group, so do they also change the group\u27s members. In consequence, a complete analysis of individuals and their social relations requires a thorough understanding of groups and their dynamics

Large introns in relation to alternative splicing and gene evolution: a case study of Drosophila bruno-3

Background: Alternative splicing (AS) of maturing mRNA can generate structurally and functionally distinct transcripts from the same gene. Recent bioinformatic analyses of available genome databases inferred a positive correlation between intron length and AS. To study the interplay between intron length and AS empirically and in more detail, we analyzed the diversity of alternatively spliced transcripts (ASTs) in the Drosophila RNA-binding Bruno-3 (Bru-3) gene. This gene was known to encode thirteen exons separated by introns of diverse sizes, ranging from 71 to 41,973 nucleotides in D. melanogaster. Although Bru-3's structure is expected to be conducive to AS, only two ASTs of this gene were previously described. Results: Cloning of RT-PCR products of the entire ORF from four species representing three diverged Drosophila lineages provided an evolutionary perspective, high sensitivity, and long-range contiguity of splice choices currently unattainable by high-throughput methods. Consequently, we identified three new exons, a new exon fragment and thirty-three previously unknown ASTs of Bru-3. All exon-skipping events in the gene were mapped to the exons surrounded by introns of at least 800 nucleotides, whereas exons split by introns of less than 250 nucleotides were always spliced contiguously in mRNA. Cases of exon loss and creation during Bru-3 evolution in Drosophila were also localized within large introns. Notably, we identified a true de novo exon gain: exon 8 was created along the lineage of the obscura group from intronic sequence between cryptic splice sites conserved among all Drosophila species surveyed. Exon 8 was included in mature mRNA by the species representing all the major branches of the obscura group. To our knowledge, the origin of exon 8 is the first documented case of exonization of intronic sequence outside vertebrates. Conclusion: We found that large introns can promote AS via exon-skipping and exon turnover during evolution likely due to frequent errors in their removal from maturing mRNA. Large introns could be a reservoir of genetic diversity, because they have a greater number of mutable sites than short introns. Taken together, gene structure can constrain and/or promote gene evolution

Effects of deletion of the Streptococcus pneumoniae lipoprotein diacylglyceryl transferase gene lgt on ABC transporter function and on growth in vivo

Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt), deletion of the corresponding gene potentially allows the characterisation of the overall importance of lipoproteins for specific bacterial functions. We have used a Δlgt mutant strain of Streptococcus pneumoniae to investigate the effects of loss of lipoprotein attachment on cation acquisition, growth in media containing specific carbon sources, and virulence in different infection models. Immunoblots of triton X-114 extracts, flow cytometry and immuno-fluorescence microscopy confirmed the Δlgt mutant had markedly reduced lipoprotein expression on the cell surface. The Δlgt mutant had reduced growth in cation depleted medium, increased sensitivity to oxidative stress, reduced zinc uptake, and reduced intracellular levels of several cations. Doubling time of the Δlgt mutant was also increased slightly when grown in medium with glucose, raffinose and maltotriose as sole carbon sources. These multiple defects in cation and sugar ABC transporter function for the Δlgt mutant were associated with only slightly delayed growth in complete medium. However the Δlgt mutant had significantly reduced growth in blood or bronchoalveolar lavage fluid and a marked impairment in virulence in mouse models of nasopharyngeal colonisation, sepsis and pneumonia. These data suggest that for S. pneumoniae loss of surface localisation of lipoproteins has widespread effects on ABC transporter functions that collectively prevent the Δlgt mutant from establishing invasive infection