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Abstract: The first and most significant barrier against influenza infection is the mucosal-associated lymphoid tissue of the upper airways and rodent nasopharyngeal-associated lymphoid tissue (NALT) is considered equivalent to the lymphoid tissue of human Valdryer''s ring. This study is the first attempt to analyze and compare local and systemic cellular and antibody immune responses in NALT and spleen in a mouse model of experimental influenza infection and intranasal vaccination with LAIV (live attenuated reassortant influenza vaccine). It was shown that the vaccine strain completely inherited the ability to induce high-grade local antibody responses (secretory IgA+IgG+IgM), local cellular lymphoproliferative activity, CD4+, CD8+ and CD19+ lymphocyte and cytokine production responses from the virulent parental strain but it had less capacity to stimulate production of serum IgG, accumulation of CD8+ cells and IFN-γ production in the spleen. Primary non-complicated influenza infection and primary vaccination were accompanied by a short-term (24h) increase in the levels of lymphocyte apoptosis in both NALT and spleen. However, experimental data indicated that vaccination with LAIV and uncomplicated forms of influenza infection did not influence immune system apoptosis following a secondary immune response. [Copyright &y& Elsevier]

The mouse Hop2 and Mnd1 proteins, which can form a stable heterodimeric complex, ensure the proper synapsis of homologous chromosomes in meiosis by acting in concert with Rad51 and Dmc1 to promote the strand invasion (D-loop formation) step of homologous recombination. Hop2 alone promotes D-loop formation, but Mnd1 and the Hop2-Mnd1 complex do not. Here we show that only the heterodimer complex, but not the individual proteins, can stimulate strand invasion by Dmc1. Furthermore, we demonstrate that the interaction with Mnd1 provokes changes in Hop2 that are responsible not only for abrogating the recombinase activity of Hop2 but also for generating a new molecular interface able to physically interact with and stimulate Dmc1. We also show that coiled-coil motifs in Hop2 and Mnd1 are essential for their interaction with each other and that a clearly delineated region near the COOH terminus of both proteins is necessary for both the DNA binding and single-strand annealing by the Hop-Mnd1 heterodimer. Finally, we describe a point mutation in Hop2 that dissociates its strand invasion activity from its ability to bind and anneal DNA. [ABSTRACT FROM AUTHOR]

The S. cerevisiae Hop2 protein and its fission yeast homolog Meu13 are required for proper homologous chromosome pairing and recombination during meiosis. The mechanism of this requirement is, however, not understood. The previous studies in Saccharomyces suggested that Hop2 is a guardian of meiotic chromosome synapsis with the ability to prevent or resolve deleterious associations between nonhomologous chromosomes. We have generated a Hop2 knockout mouse that shows profound meiotic defects with a distinct and novel phenotype. Hop2−/− spermatocytes arrest at the stage of pachytene-like chromosome condensation. Axial elements are fully developed, but synapsis of any kind is very limited. Immunofluorescence analysis of meiotic chromosome spreads indicates that while meiotic double-stranded breaks are formed and processed in the Hop2 knockout, they fail to be repaired. In aggregate, the Hop2 phenotype is consistent with a direct role for the mouse Hop2 protein in promoting homologous chromosome synapsis. [Copyright &y& Elsevier]

• Silver monofluoride fluorinates chlorofullerenes yielding novel fullerene halides. • Cl/F exchange pathway preserves the initial addition pattern. • According to DFT studies Ag+-promoted Halex process occurs via cationic intermediates. Treatment of the skew-pentagonal-pyramid (SPP) isomer of C 60 Cl 6 with silver(I) fluoride affords displacement of chlorine addends to give mixed C 60 Cl 6– n F n compounds with n = 1–5 and pure C 60 F n fluorides with n = 2, 4, and 6. Likewise, treatment of C s -C 70 Cl 10 produces C 70 F n fluorides with n = 2–10 and a series of mixed chloro-fluoro derivatives. Several of the newly synthesized substances, SPP -C 60 Cl 5 F, SPP -C 60 ClF 5 (two isomers), SPP -C 60 F 6 , and non-symmetric C 60 F 4 and C 60 F 6 , have been isolated, and spectroscopically characterized. Their structures have been established on the basis of the 19F NMR data supplemented with DFT calculations. Our experimental data and theoretical considerations suggest that the reaction likely proceeds via Ag+-mediated elimination of chloride anion from the fullerene cage followed by fluoride anion attachment to the site thus vacated. [ABSTRACT FROM AUTHOR]