The high-altitude pre-Andean region of the Atacama Desert is characterized by its stark volcanic rock formations and unique hydrothermal gypsum outcrops (gypcrete) that it hosts. This study delves into the biomolecular composition of the endolithic phototrophic microbes that thrive within these gypcretes. Using advanced Raman spectroscopy techniques, including Raman imaging (complemented by microscopic and 3D microscopic observations), herein we unveil new insights into the adaptive strategies of these gypsum-inhabiting algae. Our Raman imaging results provide a detailed chemical map of carotenoids associated with microbial colonization. This map reveals a significant gradient in pigment content, highlighting a critical survival mechanism for algae and cyanobacteria in this polyextreme environment. Intriguingly, we detected signals for carotenoids not only in the algae-colonized layer, but also deeper within the gypsum matrix - indicating pigment migration following cell disruption. In addition, we conducted an in-depth analysis of individual algal cells from the Trebouxiaceae family, noting their color variations from green to orange, plus describing the spectral differences in detail. This investigation identified in-vivo pigments (carotenoids, chlorophyll) and lipids at the cellular level, offering a comprehensive view of the molecular adaptations enabling life in one of the Earth's most extreme habitats.

• Klíčová slova
• Astrobiology, Biomarkers, Extremophiles, Geomicrobiology, Photopigments, Raman imaging,
• MeSH
• extrémní prostředí MeSH
• fyziologická adaptace MeSH
• karotenoidy * metabolismus   MeSH
• pouštní klima * MeSH
• Ramanova spektroskopie * MeSH
• sinice metabolismus   genetika   MeSH
• síran vápenatý * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• karotenoidy * MeSH
• síran vápenatý * MeSH

Microorganisms inhabiting gypsum have been observed in environments that differ greatly in water availability. Gypsum colonized by microorganisms, including cyanobacteria, eukaryotic algae, and diverse heterotrophic communities, occurs in hot, arid or even hyperarid environments, in cold environments of the Antarctic and Arctic zones, and in saline and hypersaline lakes and ponds where gypsum precipitates. Fossilized microbial remnants preserved in gypsum were also reported. Gypsum protects the endolithic microbial communities against excessive insolation and ultraviolet radiation, while allowing photosynthetically active radiation to penetrate through the mineral substrate. We here review the worldwide occurrences of microbially colonized gypsum and the specific properties of gypsum related to its function as a substrate and habitat for microbial life on Earth and possibly beyond. Methods for detecting and characterizing endolithic communities and their biomarkers in gypsum are discussed, including microscopic, spectroscopic, chemical, and molecular biological techniques. The modes of adaptation of different microorganisms to life within gypsum crystals under different environmental conditions are described. Finally, we discuss gypsum deposits as possible targets for the search for microbial life or its remnants beyond Earth, especially on Mars, where sulfate-rich deposits occur, and propose strategies to detect them during space exploration missions.

• Klíčová slova
• astrobiology, biomarkers, cyanobacteria, endolithic communities, gypsum,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Plant growth-promoting rhizobacteria (PGPR) boost crop yields and reduce environmental pressures through biofilm formation in natural climates. Recently, biofilm-based root colonization by these microorganisms has emerged as a promising strategy for agricultural enhancement. The current work aims to characterize biofilm-forming rhizobacteria for wheat growth and yield enhancement. For this, native rhizobacteria were isolated from the wheat rhizosphere and ten isolates were characterized for plant growth promoting traits and biofilm production under axenic conditions. Among these ten isolates, five were identified as potential biofilm-producing PGPR based on in vitro assays for plant growth-promoting traits. These were further evaluated under controlled and field conditions for their impact on wheat growth and yield attributes. Surface-enhanced Raman spectroscopy analysis further indicated that the biochemical composition of the biofilm produced by the selected bacterial strains includes proteins, carbohydrates, lipids, amino acids, and nucleic acids (DNA/RNA). Inoculated plants in growth chamber resulted in larger roots, shoots, and increase in fresh biomass than controls. Similarly, significant increases in plant height (13.3, 16.7%), grain yield (29.6, 17.5%), number of tillers (18.7, 34.8%), nitrogen content (58.8, 48.1%), and phosphorus content (63.0, 51.0%) in grains were observed in both pot and field trials, respectively. The two most promising biofilm-producing isolates were identified through 16 s rRNA partial gene sequencing as Brucella sp. (BF10), Lysinibacillus macroides (BF15). Moreover, leaf pigmentation and relative water contents were significantly increased in all treated plants. Taken together, our results revealed that biofilm forming PGPR can boost crop productivity by enhancing growth and physiological responses and thus aid in sustainable agriculture.

• MeSH
• Bacteria klasifikace   genetika   metabolismus   růst a vývoj   izolace a purifikace   MeSH
• biofilmy * růst a vývoj   MeSH
• biomasa MeSH
• kořeny rostlin * mikrobiologie   růst a vývoj   MeSH
• pšenice * mikrobiologie   růst a vývoj   MeSH
• půdní mikrobiologie * MeSH
• rhizosféra * MeSH
• vývoj rostlin MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Monitoring and control of both growth media and microbial biomass is extremely important for the development of economical bioprocesses. Unfortunately, process monitoring is still dependent on a limited number of standard parameters (pH, temperature, gasses etc.), while the critical process parameters, such as biomass, product and substrate concentrations, are rarely assessable in-line. Bioprocess optimization and monitoring will greatly benefit from advanced spectroscopy-based sensors that enable real-time monitoring and control. Here, Fourier transform (FT) Raman spectroscopy measurement via flow cell in a recirculatory loop, in combination with predictive data modeling, was assessed as a fast, low-cost, and highly sensitive process analytical technology (PAT) system for online monitoring of critical process parameters. To show the general applicability of the method, submerged fermentation was monitored using two different oleaginous and carotenogenic microorganisms grown on two different carbon substrates: glucose fermentation by yeast Rhodotorula toruloides and glycerol fermentation by marine thraustochytrid Schizochytrium sp. Additionally, the online FT-Raman spectroscopy approach was compared with two at-line spectroscopic methods, namely FT-Raman and FT-infrared spectroscopies in high throughput screening (HTS) setups. RESULTS: The system can provide real-time concentration data on carbon substrate (glucose and glycerol) utilization, and production of biomass, carotenoid pigments, and lipids (triglycerides and free fatty acids). Robust multivariate regression models were developed and showed high level of correlation between the online FT-Raman spectral data and reference measurements, with coefficients of determination (R2) in the 0.94-0.99 and 0.89-0.99 range for all concentration parameters of Rhodotorula and Schizochytrium fermentation, respectively. The online FT-Raman spectroscopy approach was superior to the at-line methods since the obtained information was more comprehensive, timely and provided more precise concentration profiles. CONCLUSIONS: The FT-Raman spectroscopy system with a flow measurement cell in a recirculatory loop, in combination with prediction models, can simultaneously provide real-time concentration data on carbon substrate utilization, and production of biomass, carotenoid pigments, and lipids. This data enables monitoring of dynamic behaviour of oleaginous and carotenogenic microorganisms, and thus can provide critical process parameters for process optimization and control. Overall, this study demonstrated the feasibility of using FT-Raman spectroscopy for online monitoring of fermentation processes.

• Klíčová slova
• Carotenoids, Infrared spectroscopy, Lipids, Partial least squares (PLS) regression, Process analytical technology, Raman spectroscopy, Real-time monitoring, Rhodotorula, Schizochytrium,
• MeSH
• biomasa MeSH
• fermentace MeSH
• glukosa metabolismus   MeSH
• glycerol MeSH
• karotenoidy metabolismus   MeSH
• Ramanova spektroskopie * metody   MeSH
• triglyceridy MeSH
• uhlík * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa MeSH
• glycerol MeSH
• karotenoidy MeSH
• triglyceridy MeSH
• uhlík * MeSH

In this study, we used microscopic, spectroscopic, and molecular analysis to characterize endolithic colonization in gypsum (selenites and white crystalline gypsum) from several sites in Sicily. Our results showed that the dominant microorganisms in these environments are cyanobacteria, including: Chroococcidiopsis sp., Gloeocapsopsis pleurocapsoides, Gloeocapsa compacta, and Nostoc sp., as well as orange pigmented green microalgae from the Stephanospherinia clade. Single cell and filament sequencing coupled with 16S rRNA amplicon metagenomic profiling provided new insights into the phylogenetic and taxonomic diversity of the endolithic cyanobacteria. These organisms form differently pigmented zones within the gypsum. Our metagenomic profiling also showed differences in the taxonomic composition of endoliths in different gypsum varieties. Raman spectroscopy revealed that carotenoids were the most common pigments present in the samples. Other pigments such as gloeocapsin and scytonemin were also detected in the near-surface areas, suggesting that they play a significant role in the biology of endoliths in this environment. These pigments can be used as biomarkers for basic taxonomic identification, especially in case of cyanobacteria. The findings of this study provide new insights into the diversity and distribution of phototrophic microorganisms and their pigments in gypsum in Southern Sicily. Furthemore, this study highlights the complex nature of endolithic ecosystems and the effects of gypsum varieties on these communities, providing additional information on the general bioreceptivity of these environments.

• Klíčová slova
• cyanobacteria, endoliths, green algae, gypsum, metagenomics, phototrophs,
• Publikační typ
• časopisecké články MeSH

Oleaginous filamentous fungi can accumulate large amount of cellular lipids and biopolymers and pigments and potentially serve as a major source of biochemicals for food, feed, chemical, pharmaceutical, and transport industries. We assessed suitability of Fourier transform (FT) Raman spectroscopy for screening and process monitoring of filamentous fungi in biotechnology. Six Mucoromycota strains were cultivated in microbioreactors under six growth conditions (three phosphate concentrations in the presence and absence of calcium). FT-Raman and FT-infrared (FTIR) spectroscopic data was assessed in respect to reference analyses of lipids, phosphorus, and carotenoids by using principal component analysis (PCA), multiblock or consensus PCA, partial least square regression (PLSR), and analysis of spectral variation due to different design factors by an ANOVA model. All main chemical biomass constituents were detected by FT-Raman spectroscopy, including lipids, proteins, cell wall carbohydrates, and polyphosphates, and carotenoids. FT-Raman spectra clearly show the effect of growth conditions on fungal biomass. PLSR models with high coefficients of determination (0.83-0.94) and low error (approximately 8%) for quantitative determination of total lipids, phosphates, and carotenoids were established. FT-Raman spectroscopy showed great potential for chemical analysis of biomass of oleaginous filamentous fungi. The study demonstrates that FT-Raman and FTIR spectroscopies provide complementary information on main fungal biomass constituents.

• Klíčová slova
• biodiesel, biopolymers, carotenoids, chitin, chitosan, fatty acids, fermentation, fungi, oleaginous microorganisms, pigments,
• MeSH
• analýza hlavních komponent MeSH
• biologické pigmenty analýza   MeSH
• biomasa MeSH
• biotechnologie MeSH
• chromatografie plynová MeSH
• fosfor analýza   metabolismus   MeSH
• Fourierova analýza MeSH
• houby chemie   růst a vývoj   MeSH
• karotenoidy analýza   MeSH
• lipidy analýza   MeSH
• magnetická rezonanční spektroskopie MeSH
• Ramanova spektroskopie metody   MeSH
• spektrofotometrie ultrafialová MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• vápník metabolismus   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické pigmenty MeSH
• fosfor MeSH
• karotenoidy MeSH
• lipidy MeSH
• vápník MeSH

Photosynthetic energy conversion and the resulting photoautotrophic growth of green algae can only occur in daylight, but DNA replication, nuclear and cellular divisions occur often during the night. With such a light/dark regime, an algal culture becomes synchronized. In this study, using synchronized cultures of the green alga Desmodesmus quadricauda, the dynamics of starch, lipid, polyphosphate, and guanine pools were investigated during the cell cycle by two independent methodologies; conventional biochemical analyzes of cell suspensions and confocal Raman microscopy of single algal cells. Raman microscopy reports not only on mean concentrations, but also on the distribution of pools within cells. This is more sensitive in detecting lipids than biochemical analysis, but both methods-as well as conventional fluorescence microscopy-were comparable in detecting polyphosphates. Discrepancies in the detection of starch by Raman microscopy are discussed. The power of Raman microscopy was proven to be particularly valuable in the detection of guanine, which was traceable by its unique vibrational signature. Guanine microcrystals occurred specifically at around the time of DNA replication and prior to nuclear division. Interestingly, guanine crystals co-localized with polyphosphates in the vicinity of nuclei around the time of nuclear division.

• Klíčová slova
• Desmodesmus quadricauda, cell cycle, confocal Raman microscopy, guanine, lipids, microalgae, polyphosphate, starch,
• MeSH
• buněčná stěna chemie   MeSH
• buněčný cyklus * MeSH
• časové faktory MeSH
• Chlorophyta cytologie   růst a vývoj   MeSH
• guanin analýza   MeSH
• lipidová tělíska metabolismus   MeSH
• lipidy analýza   MeSH
• mikroskopie * MeSH
• polyfosfáty analýza   MeSH
• Ramanova spektroskopie * MeSH
• škrob analýza   MeSH
• velikost buňky MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• guanin MeSH
• lipidy MeSH
• polyfosfáty MeSH
• škrob MeSH

We present a comparison of the performance of four miniature portable Raman spectrometers for the discrimination of carotenoids in samples of carotene-producing microorganisms. Two spectrometers using a green laser allowing to obtain Resonance Raman (or pre-Resonance Raman) signals, one instrument with a 785 nm laser, and a recently developed Portable Sequentially Shifted Excitation Raman spectrometer (PSSERS) were used for identifying major pigments of different halophilic (genera Halobacterium, Halorubrum, Haloarcula, Salinibacter, Ectothiorhodospira, Dunaliella) and non-halophilic microorganisms (Micrococcus luteus, Corynebacterium glutamicum). Using all the tested instruments including the PSSERS, strong carotenoids signals corresponding to the stretching vibrations in the polyene chain and in-plane rocking modes of the attached CH3 groups were found at the correct positions. Raman spectra of carotenoids can be obtained from different types of microbiological samples (wet pellets, lyophilized culture biomass and pigment extracts in organic solvents), and can be collected fast and without time-consuming procedures.

• Klíčová slova
• Corynebacterium, Halobacterium, Halorubrum, Salinibacter, exobiology, halophiles, portable Raman spectrometers, portable sequentially shifted excitation Raman spectrometer,
• Publikační typ
• časopisecké články MeSH

Nicotine has a profound influence on the carotenoid metabolism in halophilic Archaea of the class Halobacteria. In a study of Halobacterium salinarum, Haloarcula marismortui and Halorubrum sodomense, using different analytical techniques to monitor the production of different carotenoids as a function of the presence of nicotine, we showed that the formation of α-bacterioruberin was inhibited in all. In Hbt. salinarum, addition of nicotine led to a significant change in the color of the culture due to the accumulation of lycopene, in addition to the formation of bisanhydrobacterioruberin which does not differ in color from α-bacterioruberin. Very little or no lycopene was formed in Har. marismortui and in Hrr. sodomense; instead bisanhydrobacterioruberin was the only major carotenoid found in nicotine-amended cultures. The findings are discussed in the framework of the recently elucidated biochemical pathway for the formation of the different carotenoid pigments encountered in the Halobacteria.

• Klíčová slova
• Bacterioruberin, Carotenoids, Haloarchaea, Nicotine,
• MeSH
• Euryarchaeota chemie   účinky léků   metabolismus   MeSH
• karotenoidy analýza   biosyntéza   MeSH
• nikotin farmakologie   MeSH
• nikotinoví agonisté farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• karotenoidy MeSH
• nikotin MeSH
• nikotinoví agonisté MeSH