O- vs. N-protonation of 1-dimethylaminonaphthalene-8-ketones: formation of a peri N–C bond or a hydrogen bond to the pi-electron density of a carbonyl group

X-ray crystallography and solid-state NMR measurements show that protonation of a series of 1-dimethylaminonaphthalene-8-ketones leads either to O protonation with formation of a long N–C bond (1.637–1.669 Å) between peri groups, or to N protonation and formation of a hydrogen bond to the π surface of the carbonyl group, the latter occurring for the larger ketone groups (C(O)R, R = t-butyl and phenyl). Solid state 15N MAS NMR studies clearly differentiate the two series, with the former yielding significantly more deshielded resonances. This is accurately corroborated by DFT calculation of the relevant chemical shift parameters. In the parent ketones X-ray crystallography shows that the nitrogen lone pair is directed towards the carbonyl group in all cases

Regulation of CCR7-dependent cell migration through CCR7 homodimer formation

The chemokine receptor CCR7 contributes to various physiological and pathological processes including T cell maturation, T cell migration from the blood into secondary lymphoid tissues, and tumor cell metastasis to lymph nodes. Although a previous study suggested that the efficacy of CCR7 ligand-dependent T cell migration correlates with CCR7 homo- and heterodimer formation, the exact extent of contribution of the CCR7 dimerization remains unclear. Here, by inducing or disrupting CCR7 dimers, we demonstrated a direct contribution of CCR7 homodimerization to CCR7-dependent cell migration and signaling. Induction of stable CCR7 homodimerization resulted in enhanced CCR7-dependent cell migration and CCL19 binding, whereas induction of CXCR4/CCR7 heterodimerization did not. In contrast, dissociation of CCR7 homodimerization by a novel CCR7-derived synthetic peptide attenuated CCR7-dependent cell migration, ligand-dependent CCR7 internalization, ligand-induced actin rearrangement, and Akt and Erk signaling in CCR7-expressing cells. Our study indicates that CCR7 homodimerization critically regulates CCR7 ligand- dependent cell migration and intracellular signaling in multiple cell types

Desempenho do capim-tanzânia cultivado em solução nutritiva com a omissão de macronutrientes

The effects of nutritional disorder depends on the plant nutrient and the crop species. The experiment was carried out to evaluate the effect of nutrients on the nutrition and plant growth of Panicum maximum cv. Tanzania, grown in nutrient solution. Plants of Tanzania grass were grown in pots containing nutrient solution corresponding to seven treatments, one complete and the others with individual absence of N, P, K, Ca, Mg and S, arranged in a randomized  design with three replications. After describing the symptoms of the nutrients not applied, the plants were harvested 45 days after transplantation and divided into roots and shoots, and the levels of macronutrients were determined. The removal of nutrients in Tanzania grass resulted in a decrease both of dry matter production, with emphasis on nitrogen, and nutrient uptake, producing typical visual symptoms for each nutrient. Macronutrient levels in the shoots of grass in nutrient solution and omitting the nutrients were, respectively: N = 23.6 to 11.4, P = 1.7 to 0.3, K = 15.2 to 2.0 , Ca = 3.8 to 0.7, Mg = 3.0 to 0.3 S = 1.0 to 0.6 g kg-1Os efeitos da  desordem nutricional na planta depende do nutriente e da espécie cultivada. O experimento foi desenvolvido com o objetivo de avaliar o efeito dos macronutrientes sobre a nutrição e o crescimento de plantas de Panicum maximum cv. Tanzânia, cultivado em solução nutritiva. As plantas do capim-Tanzânia foram cultivadas em vasos contendo solução nutritiva correspondendo a sete tratamentos sendo a completa e com ausência individual N, P, K, Ca, Mg e S, dispostos em delineamento inteiramente  casualizado e três repetições. Após a descrição da sintomatologia dos nutrientes não aplicados, as plantas foram colhidas, 45 dias após o transplante, divididas em raiz e parte aérea e determinado os teores de macronutrientes. A supressão dos macronutrientes em capim-tanzânia provocou diminuição na produção de matéria seca destacando-se o nitrogênio, e na absorção de nutrientes,  promovendo sintomas visuais característica para cada nutriente. Os teores dos macronutrientes na parte aérea do capim da solução nutritiva completa e com omissão dos nutrientes foram respectivamente: N = 23,6-11,4; P = 1,7-0,3; K = 15,2-2,0; Ca = 3,8-0,7; Mg = 3,0-0,3; S = 1,0-0,6 g kg-1