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Parvularia gen. nov.

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· “PROTIST–2016”
integrating the information on morphological,
molecular, and ecological features of different
protist species. The content of the web-system
will include morphological descriptions and
differential diagnoses of the species, photos of living
cells and whole mounts, electron-microscopic
illustrations of coverings and cell ultrastructure,
movies of live cells, drawings, sequences of
phylogenetically important genes, molecular
phylogenetic trees, databases on geographic and
biotopic distribution of the species, protistological
literature. Now we focus on four groups of free-living
protists: heterotrophic flagellates, testate amoebae,
ciliates, centroheliozoans. The work on interactive
illustrative keys for some taxonomic groups was
started. Registered on the website users can upload
and edit content, create personal profiles, and topics
on the forum. We invite all protistologists to join
our team. The integrated web-system is available
for observing on the Internet at http://protist.ru/.
This study was supported by the Russian Foundation
for Basic Research (grant 15-29-02518).
HIDDEN DIVERSITY OF FILOSE TESTATE
AMOEBAE IN THE MIDDLE WATERSHED
OF THE DANUBE
Török J.K.
Department of Systematic Zoology and Ecology,
Eötvös Loránd University, Budapest
torokjul@elte.hu
Diversity of filose testate amoebae in the middle
watershed of the Danube has been searched for
decades, but still features with new detections.
Corythionella golemanskyi is first time detected in
Europe in satisfactory number of individuals for
correct identification. Cyphoderia calceolus and
Cyphoderia myosurus specimens found during the last
twenty years make possible to distinguish between
these two similar and rare taxa. Reviewing all the
rare filose testaceans found in the middle watershed
of River Danube from 1962 and considering their
sampled microhabitats, we conclude that these
species are generally adapted to low organic material
content and high oxygen concentration. Testate
amoeba species lists from Hungary are compared
throughout five decades, highlighting habitat
requirements for rare filoseans. We argue, that water
flow has an important role in formation of riverine
testate amoeba communities: Space clearing floods
open new microhabitats for colonization from local
refugia. Microhabitats like sandy riparian zone
remaining free from intensive organic load are
occasionally supplied with additional fresh ground
water, and can maintain favourable environmental
conditions for filoseans for a long time, while prevent
development of diverse lobosean assemblages.
Striking similarity between assemblages of Penard
in the profundal zone of deep Swiss lakes and the
middle watershed of the Danube are attributed to
the above environmental factors. It is still debated,
why majority of the presented species have not
been reported out of Europe. Finally, a concise
methodological proposal is presented to the detection of these inconspicuous testate amoeba
species. Funding: Hungarian Scientific Research
Fund (T49632).
RARE CORYTHIONELLA AND CYPHODERIA
SPECIES IN THE HUNGARIAN SECTION OF
THE DANUBE
Török J.K.
Department of Systematic Zoology and Ecology,
Eötvös Loránd University, Budapest
torokjul@elte.hu
Sandy sediment and seston were investigated
in several sites north from Budapest along the
Danube riparian zone in order to find rare filose
testate amoebae. Finally, ca. 20 kilometers north
from the capital Corythionella golemanskyi tests
were detected in 2015, enough for morphometric
analysis. A repeated sampling four months later
resulted specimens of Cyphoderia calceolus with
enormous form variations. Shell structure details
and morphometry are given for both species.
Characteristics of the latter are compared with
those of Cyphoderia myosurus, detected in 1996–97
sampling of the Danube in the Szigetköz area. As
Penard (1908) has stated, Cyphoderia myosurus
has elongated shell plates. Cyphoderia calceolus,
however, comprises non-overlapping plates, often
kidney shaped, without a regular circular outline.
Morphometry of Corythionella golemanskyi shells
leads us to conclude that the formerly found active
Corythionella specimens (sampled in Szigetkö z
Danube, 1996) belong to another species. The very
first Corythionella specimens ever found in Hungary
were detected as early as 1996 at the same site, but
being not yet described, they were preserved as weird
Cyphoderia laevis specimens. These data suggest that
although Corythionella is present in the Danube, its
shy appearence prevents it from recognition during
analysis of turbid sediment samples. Funding:
Hungarian Scientific Research Fund (T49632).
PARVULARIA GEN. NOV. REPRESENTS A
FILOSE AMOEBA RELATED TO NUCLEARIIDS, THE EARLIEST-BRANCHING LINEAGE OF HOLOMYCOTA (OPISTHOKONTA)
Torruella G.1, López-Escardó D.2, Moreira D.1,
Ruiz-Trillo I.2,3, López-García P.1
Protistology
- Unit é d’Ecologie, Syst é matique et Evolution,
Université Paris-Sud 11, France
2
- Institut de Biologia Evolutiva (CSIC-Universitat
Pompeu Fabra), Catalunya
3
- Institució Catalana de Recerca i Estudis Avançats
(ICREA)
guifre.torruella@u-psud.fr
Opisthokonts, one of the largest eukaryotic supergroups, is divided into two major clades: the Holozoa,
encompassing animals and their unicellular relatives,
and the Holomycota, including fungi and their
unicellular relatives. The earliest-branching lineage
in Holomycota, which has received many names
(e.g. Nucleariidae, Cristidiscoidia, Discicristata),
remains poorly studied. This group of phagotrophic
filose amoebae bears contrasting features in comparison with those of their close relatives, the
parasitic Opisthosporidia and the osmotrophic fungi.
It originally contained a single genus, Nuclearia,
which includes naked amoebae of ca. 40 µm cell
diameter that feed on filamentous cyanobacteria in
freshwater environments. More recently, Fonticula
alba was included as sister to Nuclearia spp. With
much smaller cell size and bacterivore, this amoeba
presents an aggregative multicellular fruiting body.
Here we describe the new genus Parvularia nov.
gen., a small filose amoeba formerly called Nuclearia
sp. ATCC50694, and we compare its morphological
features with those of the genera Nuclearia and
Fonticula. We also review the whole nucleariid
lineage at the onset of Holomycota, focusing on their
diversity, ecology and evolutionary importance.
SSU rRNA-based phylogenetic analyses including
environmental sequences suggest that nucleariids are
relatively scarce and thrive exclusively in freshwater
systems. Based on existing transcriptomic data for
Parvularia and novel data for a canonical Nuclearia
strain, we carried out phylogenomic analyses to
study the internal phylogeny of the whole group.
Nucleariids occupy a key evolutionary position, such
that mapping phenotypic traits on the phylogeny
of Opisthokonts will help understanding important
evolutionary transitions such multicellularity,
parasitism or osmotrophy.
1
TESTATE AMOEBA IN BAU SEN AND BAU
TRANG LAKES, BINH THUAN PROVINCE,
VIETNAM
Tran Q.H., Nguyen T.H.T.
Vietnamese-Russian Tropical Center
hoantran2985@gmail.com
The species composition and distribution of testate
amoebae in Bau Sen and Bau Trang lakes (Binh
Thuan Province, Vietnam) were investigated.
Fifty-three species, varieties and forms have been
· 83
identified from the water column and sediments.
Twenty-seven species, varieties and forms from the
genera Arcella, Centropyxis, Cyclopyxis, Difflugia and
Pyxidicula were found in Vietnam for the first time.
The updated list of testate amoebae in Vietnam now
includes 286 taxa. The genera Arcella, Centropyxis and
Difflugia are characterized by the highest frequency
of occurrence. The species diversity of Arcella,
Centropyxis, Difflugia was the highest. Centropyxis
aculeata, Arcella discoides, Difflugia schurmanni,
Netzelia oviformis and Difflugia limnetica were the
most common species. Some taxa have shown
restricted distribution, e.g. Lesquereusia modesta
was found in Bau Trang lake with a high frequency
of occurrence, but was not observed in Bau Sen lake.
The number of observed species,varieties and forms
in each lake is 34. The average number of the species
per sample on the shores of the lakes subjected to
human agricultural activity was significantly higher
than in the samples from the shores of the lakes
with less anthropogenic disturbance. The curves of
“cumulative species number vs. sampling effort” are
well fitted by equations S = 7.60N0.69 for Bau Sen
lake and S = 12.52N0.46 for Bau Trang. The curves
are unsaturated, which indicates that more intensive
investigations of testate amoebae should be expected
to reveal more species.
DIVERSITY OF THE GENUS MONOCERCOMONOIDES
Treitli S.C.1, Kotyk M.2, Yubuki N.1, Vlasáková
J.1, Šrámová E.1, Smejkalová P.1, Novotná K.K.1,
Čepička I.2, Hampl V.1
1
- Charles University in Prague, Faculty of Science,
Department of Parasitology, Prague, Czech Republic
2
- Charles University in Prague, Faculty of Science,
Department of Zoology, Prague, Czech Republic
treitlis@natur.cuni.cz
Monocercomonoides sp. is a genus of small flagellates
belonging to the order Oxymonadida. They live as
intestinal endosymbionts of insects, but some of
them can be found also in the intestine of vertebrates.
In this work we sequenced the SSU rRNA of 35
different strains of Monocercomonoides isolated
from various insect and vertebrate hosts and from
unused cesspit. We have performed phylogenetic
analysis in order to understand the diversity of
this genus. Our preliminary results indicate large
variation among strains at the genetic level with
some strains having a typical 1800 bp SSU and
some having around 3000 bp SSU sequence. The
strains formed two clades, potentially distinct
genera, however the position of these clades in the
oxymonad trees is unclear and we have so far not
found any good diagnostic feature discriminating
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