Because the fastest response time, measured in terms of [tLD.sub.50], was [is less than] 4 hr at 37 [+ or -] 3 [degrees] C (the optimum Btk or Bti spore outgrowth temperature) and because 5-20% of these spores remained viable, even under the harshest pH and temperature conditions used by the human body defense system (2), these spores have the potential to survive and also to propagate in an in vivo mammalian environment.
Spore outgrowth from BT products as well as from the controls, B.
Enumeration of the shed cells based on separate exposure assays (n = 20) revealed that 43 [+ or -] 12% of the cells had degraded beyond recognition as long as one spore was present per assay well and its outgrowth was permitted.
Exposures to intact or solubilized PIBs and the liquid, particulate-free fractions of BT products (Figures 4 and 6) caused little human cell damage as compared to that seen whenever spores were present and their outgrowth was not prevented by antibiotic.
In the absence of human cells, spore outgrowth was found to be [is less than or equal to] 4% in either fresh DMEM or in medium conditioned for 8 or 24 hr with any of the human cell monolayers.
Polypeptide analysis of VCP produced at various stages of spore outgrowth indicated considerable size heterogeneity, ranging from 5 kDa to [is greater than] 200 kDa.
The direction of neurite outgrowth in relation to topographic guidance cues was assessed using the "directionality" plugin in ImageJ (open source software).
To investigate if human PSC-derived cortical neurons would respond similarly to topography, we seeded DIV40 neural progenitor cells (NPC) from three human PSC lines (H9, 0028, and CRL-2522) on these micropatterned substrates and assessed neurite outgrowth 24 hours later.
We selected a pillar configuration with pillar spacing of 1.4 [micro]m, as this spacing promoted maximal neurite outgrowth (Figure 2(c)).
Visual inspection of the cultures revealed topography directed neurite outgrowth for all PSC lines.
Morphological analysis and quantification of neurite outgrowth showed that microtopography enhanced neurite outgrowth (Figure 6(b)).
We demonstrated that plating of PSC neural progeny on microgroove and micropillar substrates significantly affected the number of differentiating neuronal cells from PSCs, significantly decreased the frequency of immature NESTIN positive NPCs persisting in PSC progeny, and increased the neurite outgrowth length, as well as neurite alignment.