Biology 625
ANIMAL PARASITOLOGY
Fall semester lecture note outline

Updated: 29 October 2003

1. sometimes considered either a subphylum or class. Recent classification places the opalinids as heterotrophic stramenophiles within the order Slopalinida Patterson, 1989.
2. most species in anura.
3. numerous flagella present, in oblique and parallel rows over entire body of protozoan. Superficially look like ciliates.
   1. rows of flagella termed kineties.
   2. between kineties, cell surface lies in delicate parallel folds that allows intereference of reflected light and opalescence
4. comments concerning typical (traditional) opalinids
   1. for traditional opalinids, anterior end of the organism is defined as the direction of travel. The anterior margin is usually hyaline, against which the anterior ends of the kineties abutt. This is termed the falx.
   2. left-handed spiral path of movement
   3. syngamy (sexual reproduction) present; anisogamous
   4. typically endocommensals in cloaca of anuras; however, fish, salamanders, reptiles, and some invertebrates harbor species as well
   5. no mouth; nutrition via pinocytosis
   6. no contractile vacuole
   7. nuclei large in binucleate forms; small in multinucleate forms; no macronucleus or micronucleus
5. life-cycle of traditional opalinid (typical of Opalina ranarum)
   1. multinucleate trophozoites in cloacal area of adult frogs
   2. divide by binary fission most of year
   3. mid-February to mid April, cysts and sexual cycle occurs
   4. about 2 weeks prior to breeding, acceleration of binary fission occurs
   5. plasmotony (numerous smaller forms, 30-90 micrometers long and with fewer nuclei, generated
   6. encyst; cysts 30-70 micrometers in diameter and with 2-12 nuclei each; passed out with feces;
   7. eaten by tadpole
   8. excysts (gamonts)
   9. numerous divisions, including meiosis
   10. 2 types of gametes produced
       1. larger, macrogametes
       2. smaller, microgametes
   11. anisogamous gametes fuse (syngamy)
   12. zygote divides often
   13. zygotes encyst (zygocyst or cytozygote)
   14. cysts exit with feces
   15. eaten by new tadpoles; excysts
   16. grows and becomes multinucleate and resides in anuran gut until next breeding season
   17. cyst formation can be induced experimentally by injecting sex or gonadotropin hormones into frogs
6. over 400 known species; very common in anurans
7. two families
   1. Proteromonadidae
      1. Proteromonas (4 spp.)
         1. 2 apical flagella
         2. single nucleus
         3. large dictyosomal complex located near anterior end
         4. surface not markedly ridged
         5. in lizards, caudata, mammals
      2. Karotomorpha (several spp.)
         1. 4 long apical flagella
         2. single nucleus
         3. large dictyosomal complex located near anterior end
         4. surface markedly ridged
         5. in amphibia
   2. Opalinidae
      1. Protozelleriella
         1. binucleate
         2. long, thin, marginal falx almost perpendicular to the anteriorposterior axis of the cell
         3. peripheral hyaline margin devoid of flagella
         4. crenulate posterior margin
         5. mushroom-shaped profile
      2. Zelleriella
         1. binucleate
         2. long, thin, marginal falx almost perpendicular to the anteriorposterior axis of the cell most species broadly ellipsoidal to ovoidal and dorsoventrally flattened; few species with mushroom-shaped body
      3. Opalina
         1. multinucleate
         2. long, thin, marginal falx almost perpendicular to the anteriorposterior axis of the cell
         3. kineties cover body evenly (no hyaline margin devoid of flagella)
         4. broad and elongate forms
         5. dorsoventral suture line at posterior of cell
         6. most species broadly ellipsoidal or ovoidal and dorso-ventrally flattened
      4. Protoopalina
         1. binucleate
         2. short, broad, axial falx almost parallel to the anterioposterior axis of the cell
         3. kineties cover body evenly
         4. most species with an elongate, cylindroid body
      5. Cepeda
         1. multinucleate
         2. short, broad, axial falx almost parallel to the anterioposterior axis of the cell
         3. kineties cover body evenly
         4. most species with an elongate, cylindroid body
      6. Hegneriella (needs verification)
         1. mononucleate
         2. long, thin, marginal falx almost parallel to the anterioposterior axis of the cell
         3. kineties cover body evenly
         4. only three described species
      7. Bezzenbergeria (needs verification)
         1. tetranucleate
         2. short, broad, axial falx almost parallel to anterioposterior axis of the cell
         3. kineties cover body evenly
         4. two described species

Reviews of the opalinids:

Delvinquier, B.L.J. and D.J. Patterson. 2000. Order Slopalinida Patterson, 1989. In, The Illustrated Guide to the Protozoa, 2nd edition. Society of Protozoologists, Allen Press, Lawrence, KS. pp. 754-758.

Delvinquier, B.L.J. and D.J. Patterson. 1992. The Opalinids. In, Kreier, J.P. and Baker, J.R., editors. Parasitic Protozoa, 2nd edition. Volume 3. Academic Press, San Diego. pp. 247-325.