[Leish-l] Fw: Fwd: Re: sandfly, mosquito ..

Petr Volf volf at cesnet.cz
Wed Apr 8 08:24:04 BRT 2009


I fully agree with the opinion presented by Paul. Just I think we need to 
clarify the name of the stage attached to the midgut.  Promastigotes 
attached to cuticular lining of the foregut (including the stomodeal valve) 
and the hindgut are true "Haptomonads", morphologically very specific, with 
hemidesmosomes etc. Those attached to midgut epithelium have morphology 
similar to nectomonads (and no hemidesmosomes) but I have problem to call 
them "nectomonads" as the name "nectomonad" is by definition something like 
"free moving flagellated forms". Any suggestions?

Best wishes
Petr


----- Original Message ----- 
From: "Bates, Paul" <pbates at liverpool.ac.uk>
To: <volf at cesnet.cz>; <leish-l at lineu.icb.usp.br>
Sent: Wednesday, April 08, 2009 10:59 AM
Subject: RE: [Leish-l] Fwd: Re: sandfly, mosquito ..


I would add a couple of points to what Petr has said (if anybody is 
interested!).

My view is that although there are some (undefined) "rules" about using 
names, in general these are meant to be helpful in understanding the 
underlying biology. If they are useful they will be used, if not they will 
become forgotten and replaced by more useful terms.

Regarding short promastigotes = short nectomonads = leptomonads (in our 
terminology), the usefulness of this term is intended to reflect the 
different role of this form in life cycle progression (based on our current 
understanding - which could change of course). What distinguishes these 
forms is that they are dividing (unlike nectomonads), they are the 
precursors of metacyclic promastigotes, they produce promastigote secretory 
gel, and the major population (along with metacyclics) in late stage 
infections. Giving these forms a different name is (in my view) helpful in 
emphasising their different bioogical properties.

"Haptomonad" should be reserved for attached forms, but only those that 
develop hemidesmosomal flagellar attachment to the foregut, stomodeal valve 
or hindgut, as these are functionally and morphologically different to 
attached forms on the midgut epithelium i.e. mediated by receptors and 
ligands (LPG etc.). These latter forms are often nectomonads!

More problematic than either of the above is the general misuse of the term 
procyclic promastigote, often used rather loosely to mean anything other 
than metacyclic promastigotes. We can argue about nomenclature of some of 
the forms above, but it is clear that to lump them all together is a mistake 
and obscures our thinking. "Procyclic" should be reserved for the first 
stages found in the flies - a rather weakly motile replicating form that are 
precursors of nectomonads.

[On a related issue it has always amused me how exercised people can get 
over axenic vs. tissue amastigotes, their similarities or differences. 
Definitely an important issue, I agree, but what about "axenic 
promastigotes", because for sure what we grow in our culture flasks is often 
very different to what we see in sand flies! Cultures tend to be a mixture 
of the replicating forms, procyclics and leptomonads, which of course never 
occur together in vivo in time or space].

For a good review on this topic see Shaden Kanhawi's review in Trends in 
Parasitology from a few years ago.

Paul Bates.
________________________________________
From: leish-l-bounces at lineu.icb.usp.br [leish-l-bounces at lineu.icb.usp.br] On 
Behalf Of volf at cesnet.cz [volf at cesnet.cz]
Sent: 07 April 2009 09:12
To: leish-l at lineu.icb.usp.br
Subject: [Leish-l] Fwd: Re:  sandfly, mosquito ..

The sequence of forms described by Paul we saw in many parasite-vector
pairs. However, we try to be more precise as concerns the terminology of
forms.

Haptomonad is any form which is attached. Nectomonad is any form which is
freely moving in the midgut lumen. Therefore one word only is not
suitable do define the parasite stage. Good terminology of forms was
invented in 20th century already. Detailed description with all
measurements are given for example by Walters et al, 1989 and Walters
1993, and Cihakova and Volf, 1997.

Very long forms originating from procyclics should be called "Long
nectomonads". These occur in partially digested bloodmeal and escape to
ectoperitrophic space of the midgut. Next form prevailing in defecated
females is short and small. Paul Bates and Mattew Rogers gave them a name
"Leptomonad", however, it is a synonym of previously used "Short
promastigotes" or "Short nectomonads" by Walters (and us). Long or short
nectomonads can attach and become haptomonads.

In our terminology the sequence of nectomonad forms is:
Procyclics (oval, short flagellum, within the bloodmeal)
Long nectomonads (see above)
Short nectomonads (or leptomonads if you wish)
Metacyclics (highly motile, with long flagellum, different LPG etc)

Best wishes
Petr Volf


----- Forwarded message from jacobsr at cc.huji.ac.il -----
    Date: Mon, 06 Apr 2009 12:08:07 +0300
    From: Jake Jacobson <jacobsr at cc.huji.ac.il>
Reply-To: Jake Jacobson <jacobsr at cc.huji.ac.il>
 Subject: Re: [Leish-l] sandfly, mosquito ..
      To: leish-l at lineu.icb.usp.br

At 08:56 PM 04/04/09, you wrote:
>Let's talk about something else!
>Bob K-K

I agree - enough is enough already so soon.
Surely a suitable subject for discussion is the etymology of the
flagellated forms in the sand fly.
in the mid-20th Century we changed from Leishman-Donovan bodies to
amastigotes and leptomonads to promastigotes.
Now at the beginning of the 21st C we have:
"The developmental sequence of the five major promastigote forms:
procyclic promastigotes, nectomonad promastigotes, leptomonad
promastigotes, haptomonad promastigotes and metacyclic promastigotes.
The exact position of haptomonad promastigotes in the developmental
sequence is uncertain". Bates
PA
<http://www.sciencedirect.com//science/journal/00207519>International
Journal for
Parasitology
<http://www.sciencedirect.com//science?_ob=PublicationURL&_tockey=%23TOC%235057%232007%23999629989%23662628%23FLA%23&_cdi=5057&_pubType=J&view=c&_auth=y&_acct=C000032999&_version=1&_urlVersion=0&_userid=626711&md5=07330fba5b44fa1b4646d911b337b0f6>Volume
37, Issue 10, August 2007, Pages 1097-1106.
Does anyone know whether all these morphs occur in all species in
their phlebotomine hosts? And is monad the correct suffix for these forms?
Monad = unity and/or a flagellated protozoan (as of the genus Monas).
Jake Jacobson




Dr.R.L.Jacobson MPH PhD
Department of Parasitology
The Hebrew University-Hadassah Medical School
POB 12272, Jerusalem, 91120
Israel
Telephone 972-2-6758077
Fax          972-2-6757425
Mobile 054-4970731
NEW:
VOIP (from USA)  415-963-9801   (up to 17:00hrs EST)
No amount of experimentation can ever prove me right; a single
experiment can prove me wrong.
Albert E.



----- End forwarded message -----= 



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