Michal Koblizek

Michal Koblizek
The Czech Academy of Sciences | AVCR · Dept of Phototrophic Microorganisms - Algatech

Dozent, Ph.D.

About

295
Publications
79,134
Reads
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5,966
Citations
Citations since 2017
92 Research Items
2655 Citations
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20172018201920202021202220230100200300400500
20172018201920202021202220230100200300400500
Introduction
My research interest is physiology, genetics and ecology of phototrophic organisms
Additional affiliations
September 2002 - present
The Czech Academy of Sciences
Position
  • Researcher
September 2000 - August 2002
Rutgers, The State University of New Jersey
Position
  • PostDoc Position

Publications

Publications (295)
Article
Full-text available
The bacterium Gemmatimonas phototrophica AP64 isolated from a freshwater lake in the western Gobi Desert represents the first phototrophic member of the bacterial phylum Gemmatimonadota. This strain was originally cultured on agar plates because it did not grow in liquid medium. In contrast, the closely related species G. groenlandica TET16 grows b...
Article
Full-text available
Aerobic anoxygenic photoheterotrophic (AAP) bacteria represent a functional group of prokaryotic organisms that harvests light energy using bacteriochlorophyll-containing photosynthetic reaction centers. They represent an active and rapidly growing component of freshwater bacterioplank-ton, with the highest numbers observed usually in summer. Speci...
Article
Photoheterotrophic bacteria harvest light energy using either proton-pumping rhodopsins or bacteriochlorophyll (BChl)-based photosystems. The bacterium Sphingomonas glacialis AAP5 isolated from the alpine lake Gossenköllesee contains genes for both systems. Here, we show that BChl is expressed between 4°C and 22°C in the dark, whereas xanthorhodops...
Article
Possibly the most abundant group of anoxygenic phototrophs are marine photoheterotrophic Gammaproteobacteria belonging to the NOR5/OM60 clade. As little is known about their photosynthetic apparatus, the photosynthetic complexes from the marine phototrophic bacterium Congregibacter litoralis KT71 were purified and spectroscopically characterised. T...
Article
Full-text available
The functions of both (bacterio) chlorophylls and carotenoids in light-harvesting complexes have been extensively studied during the past decade, yet, the involvement of BChl a high-energy Soret band in the cascade of light-harvesting processes still remains a relatively unexplored topic. Here, we present transient absorption data recorded after ex...
Preprint
Full-text available
Mitochondrial cristae expand the surface area of respiratory membranes and ultimately allow for the evolutionary scaling of respiration with cell volume across eukaryotes. The discovery of Mic60 homologs among alphaproteobacteria, the closest extant relatives of mitochondria, suggested that cristae might have evolved from bacterial intracytoplasmic...
Article
Full-text available
Phototrophic Gemmatimonadetes evolved the ability to use solar energy following horizontal transfer of photosynthesis-related genes from an ancient phototrophic proteobacterium. The electron cryo-microscopy structure of the Gemmatimonas phototrophica photosystem at 2.4 Å reveals a unique, double-ring complex. Two unique membrane-extrinsic polypepti...
Article
Full-text available
Bacteria are an important part of every ecosystem that they inhabit on Earth. Environmental microbiologists usually focus on a few dominant bacterial groups, neglecting less abundant ones, which collectively make up most of the microbial diversity. One of such less-studied phyla is Gemmatimonadota. Currently, the phylum contains only six cultured s...
Article
Full-text available
Dental biofilm is a complex microbial community influenced by many exogenous and endogenous factors. Despite long-term studies, its bacterial composition is still not clearly understood. While most of the research on dental biofilms was conducted in humans, much less information is available from companion animals. In this study, we analyzed the co...
Article
Full-text available
Growth is one of the main manifestations of life. It is assumed generally that bacterial growth is constrained mostly by nutrient availability (bottom-up control) and grazing (top-down control).
Article
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Reverse-transcription quantitative PCR (RT-qPCR) is currently the most sensitive method to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19). We analysed 1927 samples collected in a local public hospital during the autumn 2020 peak of the pandemic in the Czech Republic. The tests w...
Article
Full-text available
Gemmatimonas phototrophica AP64 is the first phototrophic representative of the bacterial phylum Gemmatimonadetes . The cells contain photosynthetic complexes with bacteriochlorophyll a as the main light-harvesting pigment and an unknown carotenoid with a single broad absorption band at 490 nm in methanol. The carotenoid was extracted from isolated...
Preprint
Full-text available
Dental biofilm is a complex microbial community influenced by many exogenous and endogenous factors. Despite long-term studies, its bacterial composition is still not clearly understood. While most of the research on dental biofilms was conducted in humans, much less information is available from companion animals. In this study, we analyzed the co...
Article
Full-text available
Bacteria are an active and diverse component of pelagic communities. The identification of main factors governing microbial diversity and spatial distribution requires advanced mathematical analyses. Here, the bacterial community composition was analysed, along with a depth profile, in the open Adriatic Sea using amplicon sequencing of bacterial 16...
Preprint
Full-text available
During their 2.7 Gyr long evolution cyanobacteria radiated into a large number of different lineages. To better understand the evolution of cyanobacteria we compared a whole genome phylogenetic tree using 1,047 concatenated single copy orthologues of Prochlorococcus marinus MIT9313 obtained from 93 reference prokaryotic species with traditional phy...
Article
Full-text available
An aerobic, yellow-pigmented, bacteriochlorophyll a-producing strain, designated AAP5 (=DSM 111157=CCUG 74776), was isolated from the alpine lake Gossenköllesee located in the Tyro-lean Alps, Austria. Here, we report its description and polyphasic characterization. Phylogenetic analysis of the 16S rRNA gene showed that strain AAP5 belongs to the ba...
Preprint
Full-text available
Gemmatimonas phototrophica AP64 is the first phototrophic representative of bacterial phylum Gemmatimonadetes. The cells contain photosynthetic complexes with bacteriochlorophyll a as the main light-harvesting pigment. In addition, the complexes contain a carotenoid with a single broad absorption band at 490 nm in methanol. A combination of nuclear...
Article
Full-text available
Members of the bacterial phylum Gemmatimonadota are ubiquitous in most natural environments and represent one of the top 10 most abundant bacterial phyla in soil. Sequences affiliated with Gemmatimonadota were also reported from diverse aquatic habitats; however, it remains unknown whether they are native organisms or represent bacteria passively t...
Article
Full-text available
Gemmatimonas phototrophica is, so far, the only described phototrophic species of the bacterial phylum Gemmatimonadetes. Its cells contain a unique type of photosynthetic complex with the reaction center surrounded by a double ring antenna, however they can also grow in the dark using organic carbon substrates. Its photosynthesis genes were receive...
Article
Full-text available
The bacterial phylum Gemmatimonadetes contains members capable of performing bacteriochlorophyll-based phototrophy (chlorophototrophy). However, only one strain of chlorophototrophic Gemmatimonadetes bacteria (CGB) has been isolated to date, hampering our further understanding of their photoheterotrophic lifestyle and the evolution of phototrophy i...
Article
Full-text available
Photoheterotrophic bacteria represent an important part of aquatic microbial communities. There exist two fundamentally different light-harvesting systems: bacteriochlorophyll-containing reaction centers or rhodopsins. Here, we report a photoheterotrophic Sphingomonas strain isolated from an oligotrophic lake, which contains complete sets of genes...
Article
Full-text available
Gemmatimonas phototrophica is, so far, the only described phototrophic species of the bacterial phylum Gem-matimonadetes. Its cells contain a unique type of photosynthetic complex with the reaction center surrounded by a double ring antenna, however they can also grow in the dark using organic carbon substrates. Its photosyn-thesis genes were recei...
Article
Full-text available
Phytoplankton is a key component of aquatic microbial communities, and metabolic coupling between phytoplankton and bacteria determines the fate of dissolved organic carbon (DOC). Yet, the impact of primary production on bacterial activity and community composition remains largely unknown, as, e.g., in the case of aerobic anoxygenic phototrophic (A...
Article
Heterotrophic bacteria in the surface ocean play a critical role in the global carbon cycle and the magnitude of this role depends on their growth rates. Although methods for determining bacterial community growth rates based on incorporation of radiolabeled thymidine and leucine are widely accepted, they are based on a number of assumptions and si...
Article
Full-text available
The anoxygenic phototrophic bacteria (APB) are an active component of aquatic microbial communities. While DNA-based studies have delivered a detailed picture of APB diversity, they cannot provide any information on the activity of individual species. Therefore, we focused on the expression of a photosynthetic gene by APB communities in two freshwa...
Article
Full-text available
The influence of temperature on photosynthetic reactions was investigated by a combination of time-resolved bacteriochlorophyll fluorescence, steady-state and differential absorption spectroscopy, and polarographic respiration measurements in intact cells of purple non-sulphur bacterium Rhodospirillum rubrum. Using variable bacteriochlorophyll fluo...
Article
Aerobic anoxygenic phototrophic (AAP) bacteria are a common component of freshwater microbial communities. They harvest light energy using bacteriochlorophyll a-containing reaction centers to supplement their predominantly heterotrophic metabolism. We used epifluorescence microscopy, HPLC, and infrared fluorometry to examine the dynamics of AAP bac...
Article
Full-text available
In Bacteria, chromosome replication starts at a single origin of replication and proceeds on both replichores. Due to its asymmetric nature, replication influences chromosome structure and gene organization, mutation rate and expression. To date, little is known about the distribution of highly conserved genes over the bacterial chromosome. Here, w...
Article
Sulfide‐driven anoxygenic photosynthesis is an ancient microbial metabolism that contributes significantly to inorganic carbon fixation in stratified, sulfidic water bodies. Methods commonly applied to quantify inorganic carbon fixation by anoxygenic phototrophs, however, cannot resolve the contributions of distinct microbial populations to the ove...
Preprint
Full-text available
Sulfide-driven anoxygenic photosynthesis is an ancient microbial metabolism that contributes significantly to inorganic carbon fixation in stratified, sulfidic water bodies. Methods commonly applied to quantify inorganic carbon fixation by anoxygenic phototrophs, however, cannot resolve the contributions of distinct microbial populations to the ove...
Article
Full-text available
Temperature is one of the most important physical factors affecting microbial and biochemical processes. We investigated the performance of photosynthetic apparatus of marine photoheterotrophic bacterium Dinoroseobacter shibae under various temperatures. The primary photochemistry and electron transport was measured using variable infra-red fluorom...
Article
Soil microbes evolved complex metabolic strategies including photoprotective and photosynthetic pigments to survive the environmental stress including high UV irradiance, oscillating temperature and drought. Despite pigment importance for survival of soil microbes in alpine ecosystems, there have been few efforts documenting the soil pigment conten...
Article
Full-text available
Genotypic and morphological diversity of cyanobacteria in the Rupite hot spring (Bulgaria) was investigated by means of optical microscopy, cultivation, single-cell PCR, and 16S rRNA gene amplicon sequencing. Altogether, 34 sites were investigated along the 71–39 °C temperature gradient. Analysis of samples from eight representative sites shown tha...
Article
Full-text available
Soda lakes, with their high salinity and high pH, pose a very challenging environment for life. Microorganisms living in these harsh conditions have had to adapt their physiology and gene inventory. Therefore, we analyzed the complete genome of the haloalkaliphilic photoheterotrophic bacterium Rhodobaca barguzinensis strain alga05. It consists of a...
Article
Full-text available
The growth rate is a fundamental characteristic of bacterial species, determining its contributions to the microbial community and carbon flow. High throughput sequencing can reveal bacterial diversity, but its quantitative inaccuracy precludes estimation of abundances and growth rates from the read numbers. Here, we overcame this limitation by nor...
Article
Full-text available
The capacity for anoxygenic photosynthesis is scattered throughout the phylogeny of the Proteobacteria. Their photosynthesis genes are typically located in a so-called photosynthesis gene cluster (PGC). It is unclear (i) whether phototrophy is an ancestral trait that was frequently lost or (ii) whether it was acquired later by horizontal gene trans...
Article
Full-text available
The majority of life on Earth depends directly or indirectly on the sun as a source of energy. The initial step of photosynthesis is facilitated by light-harvesting complexes, which capture and transfer light energy into the reaction centers (RCs). Here, we analyzed the organization of photosynthetic (PS) complexes in the bacterium G. phototrophica...
Data
Detailed discussion of the BChl a stoichiometry in PS complex. BChl, bacteriochlorophyll; PS, photosynthetic. (DOC)
Data
Flash-induced absorbance spectra of purified photosynthetic complexes of G. phototrophica. As expected for the type 2 RC, the signal is dominated by signatures of the oxidized primary donor (P870+): bleaching around 865 nm, electrochomic shift of the accessory BChl a around 800 nm and bleaching of the Qx band of the primary donor at 600 nm. BChl, b...
Data
Parameters used for computation of the steady-state optical spectra of G. phototrophica PS complex. PS, photosynthetic. (PDF)
Data
Absorption spectra of PS membranes from G. phototrophica (red) and R. rubrum (grey). PS, photosynthetic. (TIF)
Data
Upper panel: size exclusion chromatography of the partially purified PS complexes from G. phototrophica. The blue line recorded at 820 nm shows the fraction with the purified complex, and the red trace at 490 nm represent the carotenoids. Lower panel: the absorption spectrum of the obtained complex (blue) and the spectrum of the “free” carotenoids...
Data
Example of a raw TEM image of G. phototrophica complexes. TEM, transmission electron microscopy. (TIF)