Póster publicado en: 2nd FEMS Congress of European Microbiologists. Madrid (España) Fecha: 04-08/07/2006 Publicado oficialmente en: J Eukaryot Microbiol. 2010 Jul-Aug;57(4):362-8. Epub 2010 Jun 18. A new species of the genus Metacystis (Ciliophora, Prostomatida, Metacystidae) from a wastewater treatment plant. Arregui L, Pérez-Uz B, Zornoza A, Serrano S. Source Departamento de Microbiología III, Facultad de Biología, Universidad Complutense, Madrid, Spain. arregui@bio.ucm.es Abstract Unusual prostomatid specimens were found in the biological reactor of a wastewater treatment plant in a health resort in Valencia, Spain. These ciliates were attached to flocs unlike other free-swimming prostomatid ciliates described to date in the mixed liquor of activated sludge plants. The morphological study of this species led to a typically different combination of characteristics: elongated cell shape, 20-30 somatic kineties, 2 perioral kineties, and 1 circumoral kinety, 1 large vacuole protruding at the terminal end, a lorica tapered toward the aperture with a smooth neck, and 11-16 annular ridges. These characteristics place this representative as a new species of the genus Metacystis-Metacystis galiani n. sp. This species became the dominant population within the biological reactor when high values of conductivity (4,244 mS/cm) and temperature (26.8 degrees C) were recorded.

1. A New Species of the Genus Metacystis (Ciliate, Prostomatida)
from a Wastewater Treatment Plant of a Health Resort
Arregui, L1, Perez-Uz, B1, Zornoza, A 2 and Serrano, S 1
Arregui, Perez- Uz, Zornoza,
1Departamento de Microbiología III. Facultad de Biología. Universidad Complutense, Madrid, Spain. 2EGEVASA. EDAR
Complutense,
Quart-Benager. EPSAR. Valencia , Spain.
Quart- Benager.
INTRODUCTION
Ciliates, the most significant group of protists within the ecosystem of biological reactors of sewage treatment plants, can be divided into crawling and
sessile ciliates that are associated with flocs and, swimming ciliates that move freely in the mixed liquor. Species of Prostomatids, usually free-swimming
ciliates, are scarce in activated sludge WWTP, they do not usually reach high abundances and have never been reported as the dominant population in
stable conditions. The aim of this work is to describe a new species of a sessile prostomatid found associated with flocs in the biological reactor.
MATERIAL AND METHODS
Metacystis sp. was found in the biological reactor of a waste water treatment plant of a health resort located in Cofrentes, Valencia (Spain). 50 μl aliquots
containing living cells were placed on a coversliped slide and viewed by phase contrast microscopy using either an Olympus BH-5 or a Zeiss Axiostar
microscope. Specimens were stained with Flutax-2 (as described in Arregui et al. 2003) and DAPI (final concentration of 10 μg/ml), and were observed under
a Zeiss Axioplan 2 epifluorescence microscope with a CCD Spot Camera. Physico-chemical parameters were measured according to standard methods
(APHA 1989). Scale bar means 20 μm.
RESULTS and DISCUSSION
Species Diagnosis Metacystis galiana n. sp. Different stages
of the life cycle
67.6--51.6 μm
Caudal cilium
“In vivo”
Swimming
form
18.8-13.6 μm Bipartition
Elongate cell shape process
Cytostome at the anterior apical end of a retractile proboscide
Sac-like lorica tapered toward the aperture with a smooth neck and 11--16 annular ridges
Somatic ciliature formed by longitudinal kineties
Circumoral ciliature constituted by perioral girdles
One single posterior contractile vacuole
One large vacuole protruding at the cell terminal end
Rounded secreted particles often observed inside the lorica
Stained Cells
FLUTAX DAPI
Ck
Ok
OC
CIRCUMORAL INFRACILIATURE One spherical macronucleus
LSk Transversal bipartition
One circumoral kinety (dikinetids) inside the lorica
SC
Two perioral girdles (fiveand two
TSg
densely packed kinetosomes)
Single micronucleus
20-30 somatic kineties, each
constituted by eight kinetosomes
Contractile vacuole pore
PHYSICAL-CHEMICAL CONDITIONS IN THE BIOLOGICAL REACTOR OF WWTP
High conductivities due high values of sulfates, carbonates, magnesium, calcium and sodium ions and unusually high water temperature (rounding 30ºC)
S pecie s D escriptio n S hap e S ize C yto stom N um ber N um be C irc um ora l Ma Mi T erm ina l C auda l Lorica H abitat
(μm ) e of r of ciliature (μm ) V acuo le cilium
S hap e S ize N um b
som atic tra nsv
(μm ) er of
kinetie s erse
gird le s
ciliary
ring s
M etacystis S tokes, 1895 elo ngate 55 _ _ _ _ _ _ pre se nt abse nt cylind rica l, 140 pre se n brack ish
annulata w ith a nterior t
neck
M etacystis A la dro-L ube l ovo id- 10-35 centra l 22-30 5-7 2 perio ra l 3-7 abse nt cylind rica l 18-61 x abse nt m arine
borro ri and cylind ric a l x 1 circ um ora l 11-26
M artinez - 10-18
M urillo
M etacystis P ena rd, elo ngate 75-17 0 _ _ 24 _ _ _ pre se nt abse nt tub ular, _ _ freshw ate r
COMPARATIVE DATA
daphnicola 1922 curve d
GENUS Metacystis M etacystis
elongata
K ahl, 1928 cylind ric a l,
elo ngate
40-12 0 x
10
centra l 30 18-21 1 perio ra l 5,5 1 pre se nt abse nt
anterio rly
_ _ _ m arine,
brack ish
M eatcystis P ena rd, sacca te 13-20 ace ntric _ 5-6 2 perio ra l _ _ abse nt va rio us sacca te _ abse nt freshw ate r
exig ua 1922
M etac ys tis n.sp. elo ngate to 44-60.5 apic a l 20-30 8 2 (5+ 2) sing le, sing le, pre se nt pre se nt in am pho ra-like 66.4 x 2 0 11-16 bio log ica l
ga lia n a ovo id x perioral ovo id sp haeric the reactor of
15-16 1 circ um ora l al sw im m ing W W TP
(dik inetid s) sta ge
M eacystis D ietz, 1964 elo ngate 92 _ _ 4 _ _ _ pre se nt abse nt like M . _ _ m arine,
hyperh alina annulata
M etacystis P ena rd,1 922 va se -like 30 ace ntric pre se nt _ 2 perio ra l sm all 4 abse nt va rio us V ase-lik e 50-62 abse nt freshw ate r
lagenula
M etacystis K ahl, 1930 elo ngate 80-12 0 _ _ _ _ _ _ abse nt abse nt cylind rica l, _ _ freshw ate r
m egapterae sem ia nnular,
ro und ed
poste rio rly
M etacystis P ena rd, elo ngate 45-68 15 1 pre se nt 1 va se -like freshw ate r,
recurva 1922 m arine
M etacystis S tokes, 1893 cylind ric a l 50-11 0 centra l 63-66 20-24 2 perio ra l 10 1 pre se nt abse nt tub ular 100 x 48 abse nt brack ish,
striata x 2 5-39 1 circ um ora l m arine
M etacystis K ahl, 1926 cylind ric a l 50 centra l 20-26 9 1 perio ra l 1 pre se nt 1 va se -like 84 x 25 abse nt freshw ate r
tesselata
M etacystis C ohn, 18 66 ovo id- 10-91 centra l 10-18 ab unda nt 7- 1 pre se nt abse nt cylind rica l, 77-14 0 15-26 brack ish,
truncata cylind ric a l x 1 1-30 perioral cilia 14 μm annular x 2 4.5- m arine
31.5