H.M. was supported by NIH postdoctoral fellowship F32 GM095200. “
“Failing in bacteria isolation in a significant number of infections might be due to the involvement of microorganisms nonrecoverable in culture media. The presence cannot be ruled out of nondividing cells or even bacterial products still capable of promoting a host immunological response. Antibiotic therapy, for example, might induce a block of bacterial division and the impossibility of recovering cells in culture media. In these cases, a molecular method targeting DNA should be used. In this study, 230 clinical
samples with a culture-negative report obtained from 182 patients were examined with a protocol of PCR targeting the bacterial 16S rRNA gene to evaluate the usefulness of molecular methods in differencing see more culture-negative infections from other pathologies. Amplicons were obtained in 14% of the samples, although this percentage increased (27%) in a subgroup of patients with presumptive diagnosis of infection and ongoing antibiotic therapy. By multiplex PCR, it was shown that detected DNA
belonged mostly to Enterobacteriaceae and enterococcal species. selleck screening library Multiple culture-negative, PCR-positive samples and isolation of the same bacterial species in culture in additional samples from the same patient support the clinical significance of the data obtained and highlight the complementary role and usefulness of applying molecular methods in diagnostic microbiology. “
“The proteomic response of Prochlorococcus marinus MED4, subjected to extended phosphate (P) starvation, was measured utilizing the quantitative technique isobaric tags for relative and absolute quantitation. Seventeen proteins were identified as significantly more abundant in MED4 cultures grown under P-stressed conditions than the nonstressed cultures, while 14 proteins were observed to be significantly less abundant.
Proteins involved in P acquisition, and membrane-associated Ribonucleotide reductase functions such as protein folding, export and recycling as well as a protein putatively associated with maintaining DNA integrity were found to be higher in abundance than the nonstressed cultures. The effect of P starvation was also noticeable on the photosynthetic apparatus, whereby important proteins involved with light harvesting were reduced in abundance directly affecting the metabolism. This is expected, as the cell is starved of an essential nutrient; however, proteins involved in maintaining structural integrity in the photosystems are more abundant, which was not expected. We conclude that MED4 is capable of acclimating to long periods of P deprivation through a suite of processes including activating P transport and acquisition mechanisms, general stress responses, reduction of energy-related metabolic processes and importantly maintaining structural integrity in vital cell mechanisms.