The recombinant E. coli BL21 (DE3) containing the peptidase M15A gene-plasmid was induced by IPTG and the His-tagged proteins inside E. coli cells were purified using Ni NTA agarose (Qiagen, Hilden, Germany) by a gravity-flow chromatography method.
The resin-bound protein was eluted step by step by gravity flow with increasing concentrations of imidazole (10 mM, 100 mM, and 200 mM in buffer containing 200 mM NaCl and 20 mM Tris HCl, pH 7.4).
Following incubation, the chamber containing the mounted fly is washed to remove excess coelenterazine and the fly ringers with or without added drugs was then delivered to the chamber by perfusion (1 ml/min by gravity flow).
Turbidites (deposits created by a gravity-driven flow of fluidized sediments), shales, and siliciclastic rocks (sedimentary rocks made of fragments with a high silica content) can also be found in Tethyan deposits.
Ammonium ion (NH4+) solution was delivered by gravity flow through a capillary placed onto the cells.
The bound proteins were eluted from the beads by gravity flow in a Bio-Rad mini-column with increasing concentrations of imidazole (Sigma) in Ni-NTA wash buffer.
Up to 6 mLs of CSF was initially aspirated for routine microbiological and biochemical assessment, as well as concurrent studies, after which 8 mLs of CSF was collected by gravity flow into a 15 mL polypropylene tube (Greneir Bio-One188271), and placed immediately onto wet ice.
Samples were spun for 15 min at 20,000 x g to remove insoluble material, and the solubilized material was fractionated by gravity flow over a 1 ml Sephacryl-S-300 column pre-equilibrated in column buffer (50 mM HEPES [pH 7.5], 200 mM KOAc, 15 mM MgOAc2, 1 mM DTT, and 0.25% digitonin).
The source area capable of supplying sediment to the basin by sediment gravity flow (white dotted line in Figure 1) has an area of about 85 km2.
The media was recovered by gravity flow into an Em-Con filter, after which the cuff was deflated to allow the withdrawal of the catheter.
