Dear HengChiat Tai
(a) According to me Seed Solutions should be stored depending on the > stability of the crystals in the drop. If your crystal goes bad quite early > then you have to make fresh seed frequently. Its always a good habit to make > fresh seed, everytime you do streaking. > > (b) The number of drops which you can streak after dipping the whisker in > seed solution once ! Depends on your swiftness. There are robots which can > streak 12 drops continuously without the rquirement of washing in between. I > can streak upto 6 drops continuously with a gap of less than a second. But > it's always good to wash the whisker once in a while with water. If your > crystallization condition has salts like Ammonium sulfate in it, then, the > salt crystallizes quite fast on the whisker, as it is exposed to air for > some time and you may land up seeding salt crystals in to your drop. > > (c)The inconsistency, which, you have been seeing in the crystal growth is > quite common with streaking. Since it depends on how many micronuclei or > seeds get in to the drop. Some times only one seed goes into the drop and > you get a better quality single crystal in the entire drop. If two or three > seeds go into the drop during streaking the effective protein concentation > gets distribued between the seeds and as a result you have small and > numerous crystals. The only solution to this can be " Streak as many drops > as possible ". > > > Your protocol for seed preparation looks fine. > > I think you can minimize the vortex steps. If possible vortex or mix it > well with pipette. > > Choose those ends of the crystal for making seed solution which seem to > be growing. It is like inoculating the Fresh media with bacteria which are > in their early log phase of growth. > > Work with higher dilutions like, 100X and so on. Set up and streak as many > drops as possible. > All the best > Regards > > Vikas Navratna > > ------------------------------ > Hotmail® goes with you. Get it on your BlackBerry or > iPhone.<http://windowslive.com/Tutorial/Hotmail/Mobile?ocid=TXT_TAGLM_WL_HM_Tutorial_Mobile1_052009> >
