Looking at the cut-outs now, we are apt to forget how they looked before the positions of his shapes were finally mapped and traced, and before these floating, fragile forms were fixed and flattened to large paper sheets that were then laid down on canvas, and contained once again by a rectangle and a frame.
Procyclic culture forms were fixed with 2% formaldehyde at 4°C.
Promastigote forms were fixed in 4% paraformaldehyde and adhered in poly-L-lysine-treated coverslips overnight.
Colonies formed were fixed in methanol, stained in methylene blue (Sigma), and counted to determine percent survival relative to the untreated controls.
T. cruzi epimastigote or metacyclic trypomastigote forms were fixed in 4% paraformaldehyde, and 100 µl (1.0×106) of parasites were incubated in each well of a 96 well ELISA MaxiSorp plate (Nalge Nunc International) overnight at 4°C with coating buffer (0.1M Na2CO3/0.1M NaHCO3, pH 9.5).
Stationary-phase promastigote forms were fixed overnight in 2.5% glutaraldehyde, 4% of sucrose (w/v), 4% of paraformaldehyde and 5 mM of CaCl2 in 0.1 M of cacodylate buffer, and post-fixed with 1% osmium tetroxide and 0.8% potassium ferrocyanide in 0.1 M of cacodylate buffer for 1 h.
After two weeks of incubation at 37°C and 5% CO2, the colonies formed were fixed with formaldehyde, stained with Giemsa, and counted using an Oxford Optronix Colony Counter Oxford Optronix Companyy, UK).
The ratio of the numbers of atoms that can be bonded together to form molecules is fixed; for example, every water molecule contains two atoms of hydrogen and one atom of oxygen.
An. gambiae occurs throughout tropical Africa, but 2Rj is not found outside of West-Central andica and the Bamako chromosomal form that is fixed for this inversion is limited to the Niger River and its tributaries in southern Mali and northern Guinea [22].
The construction of congenic strains in breeding experiments [ 58, 59], where the mtDNA form M. rutilus is fixed in a nuclear background of M. glareolus, would allow testing if mtDNA alone alters phenotype, and ultimately, whether the mtDNA introgression has any significant fitness effects.
