Additionally, while the cytotoxicity of the POR and CAB strains was similar, the CAB2 (T3SS1 regulatory mutant) strain was strikingly more invasive than the comparable POR2 (T3SS1 structural mutant) strain. In summary, creating structural or regulatory mutations in either T3SS1 or T3SS2 causes differential downstream
effects on other virulence systems. Understanding the biological differences of strains created from a clinical isolate is critical for interpreting and understanding the pathogenic nature of V. parahaemolyticus. “
“The metabolic responses of indigenous dominant bacterioplankton populations to additions of dust were examined in the tropical northeast Atlantic. Subsurface seawater samples were learn more treated with dust, added directly or indirectly as a ‘leachate’ after its rapid dissolution in deionized water. Samples were incubated at ambient temperature and light for up to 24 h and microbial metabolic responses were assessed by 35S-methionine (35S-Met) uptake. Prochlorococcus and low nucleic acid (LNA) cells were sorted
by flow cytometry to determine their group-specific responses. Sorted cells were also phylogenetically affiliated using FISH. The high-light-adapted ecotype II dominated the Prochlorococcus group and 73±14% of LNA prokaryotes belonged to the SAR11 clade of Alphaproteobacteria. Both Prochlorococcus Selleck Acalabrutinib and LNA cells were metabolically Oxymatrine impaired by the addition of dust (40±28% and 37±22% decrease in 35S-Met uptake compared with controls, respectively). However, LNA bacterioplankton showed minor positive responses to dust leachate additions (7±4% increase in 35S-Met uptake), while the metabolic activity of Prochlorococcus cells decreased in the presence of dust leachate by 16±11%. Thus, dust dissolution in situ appears to be more deleterious to Prochlorococcus
than SAR11-dominated LNA bacterioplankton and hence could initiate a compositional shift in the indigenous bacterioplankton. Desert dust consists of soil particles that are lifted into the atmosphere when high winds occur over dry and sparsely vegetated land (Mahowald et al., 2005). With dust production estimated at about 1700 Tg year−1 (Jickells et al., 2005) and potentially increasing desertification (Rosenfeld et al., 2001), the effect of dust deposition on the indigenous microbial communities of the surface ocean can be significant. Desert dust, and its associated nutrients, can play a key role in regulating primary production (Guieu et al., 2002; Bonnet et al., 2005; Herut et al., 2005; Moore et al., 2006) and bacterial production (Herut et al., 2005; Pulido-Villena et al., 2008b) in the open ocean, as well as bacterioplankton and phytoplankton dynamics in lakes and reservoirs (Pulido-Villena et al., 2008a; Reche et al., 2009).