- MeSH
- břišní tyfus MeSH
- infekční nemoci MeSH
- mikrobiologie * MeSH
- Publikační typ
- biografie MeSH
- O autorovi
- Prowázek, Stanislav, 1875-1915 Autorita
- MeSH
- genomika MeSH
- klinické kódování MeSH
- Publikační typ
- biografie MeSH
- historické články MeSH
- O autorovi
- Šorm, František, 1913-1980 Autorita
The distribution of aerobic anoxygenic phototrophs (AAPs) was surveyed in various regions of the Mediterranean Sea in spring and summer. These phototrophic bacteria were present within the euphotic layer at all sampled stations. The AAP abundances increased with increasing trophic status ranging from 2.5 × 10(3) cells per ml in oligotrophic Eastern Mediterranean up to 90 × 10(3) cells per ml in the Bay of Villefranche. Aerobic anoxygenic phototrophs made up on average 1-4% of total prokaryotes in low nutrient areas, whereas in coastal and more productive stations these organisms represented 3-11% of total prokaryotes. Diel bacteriochlorophyll a decay measurements showed that AAP community in the Western Mediterranean grew rapidly, at rates from 1.13 to 1.42 day(-1). The lower AAP abundances registered in the most oligotrophic waters suggest that they are relatively poor competitors under nutrient limiting conditions. Instead, AAPs appear to be metabolically active organisms, which thrive better in more eutrophic environments providing the necessary substrates to maintain high growth rates.
- MeSH
- aerobní bakterie růst a vývoj izolace a purifikace MeSH
- bakteriochlorofyl A analýza MeSH
- fluorometrie MeSH
- fototrofní procesy MeSH
- mořská voda mikrobiologie MeSH
- počet mikrobiálních kolonií MeSH
- roční období MeSH
- zátoky mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Středozemní moře MeSH
We studied the distribution of anoxygenic phototrophs in 23 steppe lakes in the Transbaikal region (Russia), in Uzbekistan (Central Asia) and in the Crimean peninsula (Ukraine). The lakes varied in their mineral content and composition (salinities from 0.2 to 300 g L(-1) ). The Transbaikal lakes were alkaline (pH>9), with high amounts of soda. The Uzbek and Crimean lakes were more pH neutral, frequently with high amounts of sulfates. The presence of anoxygenic phototrophs was registered by infrared epifluorescence microscopy, infrared fluorometry and pigment analyses. In mostly shallow, fully oxic lakes, the anoxygenic phototrophs represented 7-65% of the total prokaryotes, with the maxima observed in Transbaikal soda lakes Gorbunka (32%), Khilganta (65%), Zanday (58%) and Zun-Kholvo (46%). Some of the lakes contained over 1 μg bacteriochlorophyll L(-1) . In contrast, only small amounts of anoxygenic phototrophs were present in highly mineralized lakes (>100 g total salts L(-1) ); Borzinskoe, Tsagan-Nur (Transbaikal), Staroe (Crimea) and in the residual part of the south-west Aral Sea (Uzbekistan). The oxic environment and the specific diurnal changes of bacteriochlorophyll concentration observed suggest that the phototrophic community was mostly composed of aerobic anoxygenic phototrophs. The high abundances and bacteriochlorophyll concentrations point to an important role of aerobic anoxygenic phototrophs in the habitats studied.
- MeSH
- Bacteria izolace a purifikace metabolismus MeSH
- bakteriochlorofyly analýza MeSH
- ekosystém MeSH
- fluorescenční mikroskopie MeSH
- fluorometrie MeSH
- fototrofní procesy MeSH
- mikrobiologie vody MeSH
- salinita MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Rusko MeSH
- Ukrajina MeSH
- Uzbekistán MeSH
- MeSH
- gramnegativní oxygenní fotosyntetizující bakterie izolace a purifikace MeSH
- Geografické názvy
- oceány a moře MeSH
Aerobic anoxygenic phototrophs were recently found to constitute a significant portion of the marine microbial community. These bacteria use bacteriochlorophyll-containing reaction centers to perform photoheterotrophic metabolism. A new instrument for routine measurements of both chlorophyll a and bacteriochlorophyll a was used for monitoring anoxygenic phototrophs in the Baltic Sea in late summer 2003. Bacteriochlorophyll a concentration ranged from 8 to 50 ngl(-1), with an average bacteriochlorophyll/chlorophyll ratio of 4.2 x 10(-3). Moreover, diel trends in bacteriochlorophyll a signals were observed, with a distinct decline occurring during daylight hours. Based on laboratory measurements this phenomenon was ascribed to the complete inhibition of bacteriochlorophyll synthesis by light, which, in combination with a concurrent turnover of the cells, resulted in a pigment decline. Following this explanation, we postulate that bacteriochlorophyll a can serve as a natural 'pulse-and-chase' marker, allowing estimation of the mortality rates of anoxygenic phototrophs from the rates of pigment decline. Based on this assumption, we suggest that the Baltic photoheterotrophic community was characterized by high turnover rates, in a range of 0.7-2 d(-1).
- MeSH
- aerobióza MeSH
- bakteriochlorofyl A metabolismus MeSH
- bakteriologické techniky metody přístrojové vybavení MeSH
- časové faktory MeSH
- cirkadiánní rytmus MeSH
- financování organizované MeSH
- fluorometrie přístrojové vybavení MeSH
- fotosyntéza MeSH
- mořská voda mikrobiologie MeSH
- plankton růst a vývoj MeSH
- Sphingomonadaceae růst a vývoj MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Geografické názvy
- oceány a moře MeSH
- pobaltské republiky MeSH
- MeSH
- aerobní bakterie klasifikace metabolismus MeSH
- fluorometrie metody využití MeSH
- fototropismus fyziologie MeSH
- mořská voda mikrobiologie MeSH
- Publikační typ
- kongresy MeSH
