The mechanisms involved in long-distance trafficking of FT/FTL2 remain to be elucidated. In this study, we identified the critical motifs on both FT and FTL2 required for cell-to-cell trafficking through mutant analyses using a zucchini yellow mosaic virus expression vector. Western blot analysis, performed on phloem sap collected from just beneath the vegetative apex of C.moschata plants, established that all mutant proteins tested retained the ability to enter the phloem translocation stream. However, immunolocalization see more studies revealed that a number of these FTL2/FT mutants were defective
in the post-phloem zone, suggesting that a regulation mechanism for FT trafficking exists in the post-phloem unloading step. The selective movements of FT/FTL2 were further observed by microinjection and trichome rescue studies, which revealed that FT/FTL2 has the ability to dilate
plasmodesmata microchannels during the process of cell-to-cell trafficking, and various mutants were compromised in their capacity to traffic through plasmodesmata. Based on these findings, a model is presented to account for the mechanism by which FT/FTL2 enters the phloem translocation stream and subsequently exits the phloem and enters the apical tissue, where it initiates the vegetative to floral transition.”
“Antibiotic use in the treatment of respiratory QNZ tract infections is common in primary care. The European Surveillance of Antimicrobial Consumption (ESAC programme), collecting data from 35 countries, showed that antibiotic use was highest in southern European countries. Increased antibiotic consumption has been shown by numerous ecological studies drug discovery to contribute to the emergence of antibiotic resistance in streptococci. A study comparing outpatient antibiotic consumption in the USA showed it to be similar to that in southern European countries, but macrolides, particularly azithromycin, are among the first-line agents prescribed in the USA for respiratory infections. In Europe, patients are more likely to receive a beta-lactam;
and when a macrolide is indicated, clarithromycin is more likely to be prescribed than azithromycin. Streptococci resistance to macrolides can be acquired via two mechanisms: by the mef gene, which encodes for the efflux pump mechanism, producing low to moderate resistance, or the erm gene (post-transcriptional modification of the bacterial ribosomal unit), resulting in high resistance. Macrolide resistance is mediated by erm(B) and mef(A) alone or in combination. A surveillance study showed that mef was responsible for most of the macrolide resistance seen in the USA; a decrease in the number of isolates carrying mef(A) was associated with a doubling of the number of isolates carrying both mef(A) and erm(B).