The two previously unknown species from the Baltic Sea appear to have adapted extremely well to the changing oxygen conditions of their native environment and have a cell structure that heretofore has not been observed in collared flagellates.
The funnel-shaped collar accounts for the scientific name of these protozoa, choanoflagellates (choano [Greek]: depression, funnel). They are among the protists and bacterial feeders that play a major role in the microbial food web. The collar consists of a series of filamentous cellular appendages, the microvilli. Protruding from the collar is a single flagellum, which these one-celled organisms use both to propel themselves and to swirl their bacterial food, which is then captured by the funnel and, via the microvilli, transported into the cell.
Cultivation — that is, the establishment of pure cultures under laboratory conditions — is extremely difficult and only rarely successful for these types of microorganisms. Consequently, only a small proportion of the existing marine microbial biodiversity is known. Previous research carried out by members of the IOW indicated that choanoflagellates in the oxygen-depleted areas of the central Baltic Sea are present in elevated concentrations. However, until now it has not been possible to obtain pure laboratory cultures of choanoflagellates isolated from marine low-oxygen environments (redox zones).
Exactly this feat was recently accomplished by IOW researchers with the support of Russian visiting scientists. The addition of Codosiga minima and Codosiga balthica, two previously completely unknown species of collared flagellates, further enriches the extensive culture collection of the IOW, which already includes representatives of a number of bacterial, flagellate, and ciliate species central to the Baltic Sea ecosystem. These two new members have been examined by electron microscopy and characterized in detail. Codosiga minima was so named because of its small size (about 3 microns) and it is probably one of the rarer species in the Baltic Sea. Its "big brother" (about 5 microns), however, is a common species that seems to preferentially reside in the Baltic Sea, hence the name Codosiga balthica.
Both species make use of the food sources of the low-oxygen redox zone and feed on its abundant supplies of bacteria and archaea. At the same time they enjoy a degree of protection from predators, since multicellular zooplankton (e.g., small crustaceans) rarely ventures into the low-oxygen layers. In order to take advantage of the living conditions of the redox zone, the two choanoflagellates — which evolved from oxygen-loving ancestors — have adapted in many ways to the lack of oxygen. Thus, the normally oxygen-dependent mitochondria — the energy-producing "power plants" of cells — have undergone an important change in that they can function with little or even no oxygen. This form of adaptation is absolutely unique among the collared flagellates as it has never been observed before in this group of organisms. Another surprise for the IOW researchers was that Codosiga balthica harbors intracellular bacteria. Thus, numerous bacterial cells live within each flagellated cell, where they presumably serve to support energy metabolism.
These two closely related species are now available for the first time as model organisms, which will allow experimental investigations of choanoflagellate metabolism under low-oxygen conditions. The results of such studies will no doubt help to clarify many of the as yet unanswered ecological, physiological, and evolutionary questions regarding collared flagellates.
The described work was supported by the German Research Foundation conducted. Further information on these results can be found in:
Wylezich,C., Karpov,S.A., Mylnikov,A.P., Anderson,R. and Jürgens,K. (2012) Ecologically relevant choanoflagellates collected from hypoxic water masses of the Baltic Sea have untypical mitochondrial cristae. BMC Microbiol. 12 (1), 271
Contact:Dr. Claudia Wylezich, Biological Oceanography, IOW
Dr. Barbara Hentzsch | idw
Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology
Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences