Propidium iodide stained the majority of both coiled cells and rods even when fresh cultures (24 h old) were used. After many repeats, we hypothesized that slight manipulations (ie, centrifugation or osmotic shock) of the cells may damage cell membranes thus allowing the propidium iodine to penetrate into the cells. Revival of starved cultures The growth curves of 5-month old ALG-00-530 inoculated into media with different nutrient loads

are shown in Figure 6. Cell cultured in MS broth reached the highest cell density followed by cells cultured in MS-T (no yeast extract). MS-Y broth supported cell growth but at much higher levels than MS and MS-T and the lag phase was noticeable longer in this medium. Diluted selleck chemicals MS (MD-10) produced the lowest cell density. No growth was observed in broth without nutrients (MS-S). The lag

phase extended up to 12 h post-inoculation (except for MS-Y which lasted 24 h) and significant differences in ODs were observed between MS&MS-T and MS-10&MS-Y at 24 h. Cell densities became statistically significant between all culture media after 48 h post inoculation and remained different until the end of the experiment. Figure 6 Growth curves of 5-month old Flavobacterium columnare ALG-00-530 Saracatinib molecular weight cultures incubated under different nutrient conditions. Modified Sheih (MS) medium (■), diluted MS (MS-10) (□), MS without yeast extract (MS-T) (○), MS without tryptone (MS-Y) (♦), and MS without nutrients (MS-S) (▼). Data points represent means and error bars represent standard errors. To determine what morphological changes, if any, accompanied the revival of starved cells under Dipeptidyl peptidase different nutrient conditions, we examined the cell morphology at 4, 12, and 24 h post-inoculation using both light microscopy

(data not shown) and SEM (Figure 7). Morphology of starved cells at time 0 (prior inoculation) was similar to that displayed in Figure 5. At 4 h post-inoculation, cells were scarce in all media and appeared as short rods (1–2 μm). In MS broth and MS-10, cells were covered by small spheres that in some instances (Figure 7A, B) coated most of the cell surface. This spheres resembled membrane vesicles that could derive from the external cell membrane of the cells. We did not observe any coiled forms at this time. Some cells cultured in MS-10 exhibited long fimbrie and this was not detected in any of the other media (Figure 7C). The presence of these structures may explained why at 4 h post-inoculation into MS-10, cells appeared as tight clusters under light microscopy (data not shown). At 12 h, cell become more elongated and cell division was observed in MS (Figure 7D) and MS-T. Cells reached the average size previously observed for ALG-00-530 strain after 24 h of incubation in MS and MS-T. Between 24 and 36 h post-inoculation, we observed the production of what appeared to be surface blebbing leading to membrane vesicle formation in all examined cultures (Figure 7E).