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<DIV>Patrick Bastien asks for information on the sequence of the division of
organelles of leishmanial promastogotes. Observations on Giemsa-stained smears
of <EM>L. infantum</EM> in the midgut of one of its natural vectors,
<EM>P.ariasi</EM>, show that there appears to be a constant sequence of events.
See page 407 in Killick-Kendrick (1979) In <EM>Biology of Kinetoplastida</EM>
vol 2 and the account and figures on pp 126-7 in Molyneux & Killick-Kendrick
(1987) in <EM>The Leishmaniases in Biology and Medicine</EM>, vol 1. </DIV>
<DIV>The sequence is: </DIV>
<DIV>promastogote increases in size and a second basal body appears; </DIV>
<DIV>a daughter flagellum (which stays smaller than the original throughout the
process) arises from this second basal body; </DIV>
<DIV>kinetoplast enlarges and stains diffusely - but does not divide yet; </DIV>
<DIV>nucleus enlarges and divides into two equal parts which usually lie side by
side, but are sometimes in tandem; </DIV>
<DIV>the kinetoplast, which by now lies across the body, assumes a dumbbell
shape and then divides into two equal parts; </DIV>
<DIV>the daughter kinetoplasts, lying just anterior to the nuclei, are small and
stain densely with Giemsa's stain; </DIV>
<DIV>the body of the promastigote divides into two equal parts by a
cleft that arises between the two flagella and progressively continues
posteriorly leaving one nucleus and one kinetoplast in each daughter individual.
</DIV>
<DIV>The two new promastigotes are about half the size of the original
promastigote and morphologically identical except that the flagellum of one is
shorter than that of the other. </DIV>
<DIV>In cultures, the kinetoplast sometimes divides before the nucleus, but I
have never seen this sequence in stained smears of any <EM>Leishmania
</EM>species. </DIV></BODY></HTML>