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
Rochester scientists discover gene controlling genetic recombination rates
23.04.2018 | University of Rochester
One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
23.04.2018 | Physics and Astronomy
23.04.2018 | Physics and Astronomy
23.04.2018 | Trade Fair News