Structure and composition of influenza virus. A small-angle neutron scattering study

A detailed analysis is presented of the small-angle neutron scattering curves of homogeneous solutions of influenza B virus, both intact and after treatment with bromelain, which removes the external glycoprotein spikes. The two sets of data are consistent with the following low-resolution structure: the virus particles are spherical, about 1200 A in diameter and of Mr about 180 X 10(6). The lipid bilayer is centred at a radius of 425 A, is 40 A to 50 A thick and constitutes 25% to 28% of the virus mass. The surface glycoproteins, predominantly haemagglutinin, contribute 40% to 46% of the total mass. Surprisingly little protein is found in the interior of the virus. It is suggested that the reason for this is that many particles do not contain the full complement of ribonucleoprotein complexes. These results are in good agreement with recent scanning transmission electron microscopic measurements of molecular mass and cryo-electron microscopic observations of the same preparations. Appendix 1 describes a new method of deriving spherical shell models from contrast variation neutron scattering data on viruses, in which scattering curves from all measured contrasts are used simultaneously. There is also a discussion of the assumptions and limitations implicit in the structural interpretation of such models, with emphasis on viruses containing lipid bilayers. Appendix 2 examines the effect on the scattering curves of various arrangements of the surface glycoproteins.     

A method for staining actin-containing structures in thick plastic sections for medium voltage electron microscopy

A staining procedure has been developed for imaging actin-containing structures in thick plastic sections in the electron microscope. The stress fibres of a fibroblastic cell line were used as a model system, and were first characterized immunocytochemically. After fixation of cells in formaldehyde, mordanting in a solution of gadolinium chloride allows stress fibres to be stained for light microscopy with haematoxylin. A brief exposure to a solution of ammonium paramolybdate renders haematoxylin-stained structures sufficiently electron-dense to be imaged in 1 micron thick plastic sections in a JEOL 200CX electron microscope, operating at 200 kV, and possibly in conventional instruments operating at 100 kV, particularly if equipped with a lanthanum hexaboride source.     

Multiphoton tomography visualizes collagen fibers in the tumor microenvironment that maintain cancer‐cell anchorage and shape

Second harmonic generation (SHG) multiphoton imaging can visualize fibrillar collagen in tissues. SHG has previously shown that fibrillar collagen is altered in various types of cancer. In the present study, in vivo high resolution SHG multi‐photon tomography in living mice was used to study the relationship between cancer cells and intratumor collagen fibrils. Using green fluorescent protein (GFP) to visualize cancer cells and SHG to image collagen, we demonstrated that collagen fibrils provide a scaffold for cancer cells to align themselves and acquire optimal shape. These results suggest a new paradigm for a stromal element of tumors: their role in maintaining anchorage and shape of cancer cells that may enable them to proliferate. J. Cell. Biochem. 114: 99–102, 2012. © 2012 Wiley Periodicals, Inc.     

Effect of mesenchymal stem cells on inhibiting airway remodeling and airway inflammation in chronic asthma

Previous studies proved that bone marrow‐derived mesenchymal stem cells (BMSCs) could improve a variety of immune‐mediated disease by its immunomodulatory properties. In this study, we investigated the effect on airway remodeling and airway inflammation by administrating BMSCs in chronic asthmatic mice. Forty‐eight female BALB/c mice were randomly distributed into PBS group, BMSCs treatment group, BMSCs control group, and asthmatic group. The levels of cytokine and immunoglobulin in serum and bronchoalveolar lavage fluid were detected by enzyme‐linked immunosorbent assay. The number of CD4⁺CD25⁺regulatory T cells and morphometric analysis was determined by flow cytometry, hematoxylin‐eosin, immunofluorescence staining, periodic‐acid Schiff, and masson staining, respectively. We found that airway remodeling and airway inflammation were evident in asthmatic mice. Moreover, low level of IL‐12 and high levels of IL‐13, IL‐4, OVA‐specific IgG1, IgE, and IgG2a and the fewer number of CD4⁺CD25⁺regulatory T cells were present in asthmatic group. However, transplantation of BMSCs significantly decreased airway inflammation and airway remodeling and level of IL‐4, OVA‐specific IgE, and OVA‐specific IgG1, but elevated level of IL‐12 and the number of CD4 + CD25 + regulatory T cells in asthma (P < 0.05). However, BMSCs did not contribute to lung regeneration and had no significant effect on levels of IL‐10, IFN‐Y, and IL‐13. In our study, BMSCs engraftment prohibited airway inflammation and airway remodeling in chronic asthmatic group. The beneficial effect of BMSCs might involved the modulation imbalance cytokine toward a new balance Th1–Th2 profiles and up‐regulation of protective CD4 + CD25 + regulatory T cells in asthma, but not contribution to lung regeneration. J. Cell. Biochem. 114: 1595–1605, 2013. © 2013 Wiley Periodicals, Inc.     

Addressing STEM Concepts through a Food Safety Activity

The activity described in this article engages students in learning about proper meat storage procedures by using the Internet. They apply their knowledge practically through creation of a pamphlet to be displayed in their kitchen at home and a follow-up report on their parents’ kitchen procedures; they may also participate in a classic food storage experiment. This activity is well suited for elementary school children in the second through fourth grades and promotes all basic STEM (science, technology, engineering, and math) concepts. Kitchen activities require all these concepts for successful and safe outcomes. The examination of food storage devices references engineering, and technology is used for the research and pamphlet creation. The section on bacteria introduces life sciences, and physical sciences come into play through the discussion of heat inducing change in the meats. Math skills are integral to the reference table containing temperatures and times.