Swimmingform

Caudal cilium

Bipartitionprocess

Different stagesof the life cycle

ArreguiArregui, L, L11, , PerezPerez--UzUz, B, B11, , ZornozaZornoza, A , A 22 andand Serrano, S Serrano, S 11

11Departamento de Microbiología III. Facultad de Biología. Departamento de Microbiología III. Facultad de Biología. Universidad Universidad ComplutenseComplutense, Madrid, Spain. , Madrid, Spain. 22EGEVASA. EDAR EGEVASA. EDAR QuartQuart--BenagerBenager. EPSAR. Valencia. EPSAR. Valencia , Spain., Spain.

INTRODUCTIONINTRODUCTIONCiliates, 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 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 Axiostarmicroscope. 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.

20-30 somatic kineties, each constituted by eight kinetosomes

Stained Cells

LSk

Ok

Ck

TSg

LSk

Ok

Ck

TSgTSg

OC

SC

FLUTAX DAPI

CIRCUMORAL INFRACILIATURE One circumoral kinety (dikinetids)Two perioral girdles (fiveand two densely packed kinetosomes)

Contractile vacuole pore

Single micronucleus

One spherical macronucleus Transversal bipartitioninside the lorica

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)

RESULTS RESULTS andand DISCUSSIONDISCUSSION

Elongate cell shapeCytostome at the anterior apical end of a retractile proboscideSac-like lorica tapered toward the aperture with a smooth neck and 11--16 annular ridgesSomatic ciliature formed by longitudinal kinetiesCircumoral ciliature constituted by perioral girdlesOne single posterior contractile vacuoleOne large vacuole protruding at the cell terminal endRounded secreted particles often observed inside the lorica

Species Diagnosis Metacystis galiana n. sp.

“In vivo”

COMPARATIVE DATAGENUS Metacystis

Lorica Species Description Shape S ize (μm )

Cytostome

Num ber of som atic kineties

Num ber of transverse ciliary rings

C ircum ora l ciliature

Ma(μm )

M i Term ina l Vacuole

Caudal cilium Shape S ize

(μm ) Num ber of gird les

Habitat

Metacystis annulata

Stokes, 1895 elongate 55 _ _ _ _ _ _ present absent cylindrica l, w ith anterior neck

140 present

brack ish

Metacystis borrori

Aladro-Lube l and Martinez-M urillo

ovo id-cylindrica l

10-35 x 10-18

centra l 22-30 5-7 2 periora l 1 circum ora l

3-7 absent cylindrica l 18-61 x 11-26

absent m arine

Metacystis daphnicola

Penard, 1922

elongate 75-170 _ _ 24 _ _ _ present absent tubular, curved anteriorly

_ _ freshwater

Metacystis elongata

Kahl, 1928 cylindrica l, elongate

40-120 x 10

centra l 30 18-21 1 periora l 5,5 1 present absent _ _ _ m arine, brack ish

Meatcystis exigua

Penard, 1922

sacca te 13-20 acentric _ 5-6 2 periora l _ _ absent various saccate _ absent freshwater

Metacystis galiana

n.sp. elongate to ovo id

44-60.5 x 15-16

apica l 20-30 8 2 (5+2) perioral 1 circum ora l (dik inetids)

sing le, ovo id

s ing le, sphaerical

present present in the sw im m ing stage

am phora-like 66.4 x 20 11-16 bio log ica l reactor of W W TP

Meacystis hyperhalina

Dietz, 1964 elongate 92 _ _ 4 _ _ _ present absent like M . annulata

_ _ m arine,

Metacystis lagenula

Penard,1922 vase-like 30 acentric present _ 2 periora l sm all 4 absent various Vase-like 50-62 absent freshwater

Metacystis megapterae

Kahl, 1930 elongate 80-120 _ _ _ _ _ _ absent absent cylindrica l, sem iannular, rounded posteriorly

_ _ freshwater

Metacystis recurva

Penard, 1922

elongate 45-68 15 1 present 1 vase-like freshwater, m arine

Metacystis striata

Stokes, 1893 cylindrica l 50-110 x 25-39

centra l 63-66 20-24 2 periora l 1 circum ora l

10 1 present absent tubular 100 x 48

absent brack ish, m arine

Metacystis tesselata

Kahl, 1926 cylindrica l 50 centra l 20-26 9 1 periora l 1 present 1 vase-like 84 x 25

absent freshwater

Metacystis truncata

Cohn, 1866 ovo id-cylindrica l

10-91 x 11-30

centra l 10-18 abundant perioral c ilia

7-14μm

1 present absent cylindrica l, annular

77-140 x 24.5-31.5

15-26 brack ish, m arine

67.6

--51.

6 μm

18.8-13.6 μm

A A NewNew SpeciesSpecies ofof thethe GenusGenus MetacystisMetacystis ((CiliateCiliate, , ProstomatidaProstomatida) ) fromfrom a a WastewaterWastewater TreatmentTreatment PlantPlant ofof a a HealthHealth ResortResort