Food For Thought: Short-Term Fasting Upregulates Glucose Transporters in Neurons and Endothelial Cells,But Not in Astrocytes

Neurochemical Research - Our group previously reported that 6-h fasting increased both insulin II mRNA expression and insulin level in rat hypothalamus. Given that insulin effects on central...     

Development of the dendritic cell system during mouse ontogeny

Based on the view that the efficacy of the immune system is associated with the maturation state of the immune cells, including dendritic cells (DC), we investigated the development and functional potential of conventional DC and plasmacytoid pre-DC (p-preDC) in spleen, thymus, and lymph nodes during mouse development. Both CD11c+ DC and CD45RA+ p-preDC were detected in small numbers in the thymus as early as embryonic day 17. The ratio of DC to thymocytes reached adult levels by 1 wk, although the normal CD8alpha+ phenotype was not acquired until later. Significant, but low, numbers of DC and p-preDC were present in the spleen of day 1 newborn mice. The full complement of DC and p-preDC was not acquired until 5 wk of age. The composition of DC populations in the spleen of young mice differed significantly from that found in adult mice, with a much higher percentage (50-60% compared with 20-25%) of the CD4-CD8alpha+ DC population and a much lower percentage (10-20% compared with 50-60%) of the CD4+CD8alpha- DC population. Although the p-preDC of young mice showed a capacity to produce IFN-alpha comparable with that of adult mice, the conventional DC of young mice were less efficient than those of their adult counterparts in IL-12p70 and IFN-gamma production and in Ag presentation. These results suggest that the neonatal DC system is not fully developed, and innate immunity is the dominant form of response. The complete DC system required for adaptive immunity in the mouse is not fully developed until 5 wk of age.     

Cutting edge: generation of splenic CD8+ and CD8- dendritic cell equivalents in Fms-like tyrosine kinase 3 ligand bone marrow cultures

We demonstrate that functional and phenotypic equivalents of mouse splenic CD8(+) and CD8(-) conventional dendritic cell (cDC) subsets can be generated in vitro when bone marrow is cultured with fms-like tyrosine kinase 3 (flt3) ligand. In addition to CD45RA(high) plasmacytoid DC, two distinct CD24(high) and CD11b(high) cDC subsets were present, and these subsets showed equivalent properties to splenic CD8(+) and CD8(-) cDC, respectively, in the following: 1) surface expression of CD11b, CD24, and signal regulatory protein-alpha; 2) developmental dependence on, and mRNA expression of, IFN regulatory factor-8; 3) mRNA expression of TLRs and chemokine receptors; 4) production of IL-12 p40/70, IFN-alpha, MIP-1alpha, and RANTES in response to TLR ligands; 5) expression of cystatin C; and 6) cross-presentation of exogenous Ag to CD8 T cells. Furthermore, despite lacking surface CD8 expression, the CD24(high) subset contained CD8 mRNA and up-regulated surface expression when transferred into mice. This culture system allows access to bona fide counterparts of the splenic DC subsets.     

A modified microtiter-plate test for quantification of staphylococcal biofilm formation

The tube test and the microtiter-plate test are the most frequently used techniques for quantifying biofilm formation, an important indicator for the pathogenicity of staphylococci. The purpose of the present study was to develop a modified microtiter-plate technique for quantification of biofilm formation. This technique involves fixing the bacterial film with methanol, staining with crystal violet, releasing the bound dye with 33% glacial acetic acid, and measuring the optical density (OD) of the solution at 570 nm by using an enzyme immunosorbent assay reader. Biofilm formation of 30 Staphylococcus strains was estimated by the tube test, the standard microtiter-plate test and the modified microtiter-plate test. The modified microtiter-plate test, as a quantitative assay, is superior to the tube test in terms of objectivity and accuracy. It is also superior to the standard microtiter-plate test because it enables indirect measuring of bacteria attached both to the bottom and to the walls of the wells, while in the standard test only the dye bound to the bacteria adhered to the bottom of the wells is spectrophotometrically registered. Highly significant differences between OD values obtained by the standard microtiter-plate test and those obtained by the modified test suggest that large number of bacteria were attached to the walls of the wells. Therefore, the modification of the standard microtiter-plate test by introduction of an additional step of decolorization by acetic acid seems to be a useful improvement of the technique.