BACKGROUND: Picocyanobacteria from the genera Prochlorococcus, Synechococcus, and Cyanobium are the most widespread photosynthetic organisms in aquatic ecosystems. However, their freshwater populations remain poorly explored, due to uneven and insufficient sampling across diverse inland waterbodies. RESULTS: In this study, we present 170 high-quality genomes of freshwater picocyanobacteria from non-axenic cultures collected across Central Europe. In addition, we recovered 33 genomes of their potential symbiotic partners affiliated with four genera, Pseudomonas, Mesorhizobium, Acidovorax, and Hydrogenophaga. The genomic basis of symbiotic interactions involved heterotrophs benefiting from picocyanobacteria-derived nutrients while providing detoxification of ROS. The global abundance patterns of picocyanobacteria revealed ecologically significant ecotypes, associated with trophic status, temperature, and pH as key environmental factors. The adaptation of picocyanobacteria in (hyper-)eutrophic waterbodies could be attributed to their colonial lifestyles and CRISPR-Cas systems. The prevailing CRISPR-Cas subtypes in picocyanobacteria were I-G and I-E, which appear to have been acquired through horizontal gene transfer from other bacterial phyla. CONCLUSIONS: Our findings provide novel insights into the population diversity, ecology, and evolutionary strategies of the most widespread photoautotrophs within freshwater ecosystems. Video Abstract.

• Klíčová slova
• CRISPR-Cas, Freshwater, Genome collection, Picocyanobacteria, Symbiotic interaction,
• MeSH
• ekosystém MeSH
• fylogeneze * MeSH
• fyziologická adaptace genetika   MeSH
• genom bakteriální * MeSH
• genomika MeSH
• přenos genů horizontální MeSH
• sinice * genetika   klasifikace   MeSH
• sladká voda * mikrobiologie   MeSH
• symbióza * MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH

Current research needs to be more focused on agronomical plants to effectively utilize the knowledge obtained from model plant species. Efforts to improve legumes have long employed common breeding tools. Recently, biotechnological approaches facilitated the development of improved legumes with new traits, allowing them to withstand climatic changes and biotic stress. Owing to its multiple uses and profits, alfalfa (Medicago sativa L.) has become a prominent forage crop worldwide. This review provides a comprehensive research summary of tissue culture-based genetic transformation methods, which could be exploited for the development of transgenic alfalfa with agronomically desirable traits. Moreover, advanced bio-imaging approaches, including cutting-edge microscopy and phenotyping, are outlined here. Finally, characterization and the employment of beneficial microbes should help to produce biotechnologically improved and sustainable alfalfa cultivars.

• Klíčová slova
• Advanced microscopy, bio-imaging, phenotyping, symbiotic interaction, tissue culture, transformation techniques, transgenic alfalfa,
• MeSH
• biotechnologie metody   MeSH
• elektroporace MeSH
• fixace dusíku MeSH
• geneticky modifikované rostliny genetika   MeSH
• Medicago sativa genetika   MeSH
• mikrobiota MeSH
• mikroskopie metody   MeSH
• symbolismus MeSH
• techniky tkáňových kultur metody   MeSH
• transformace genetická * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Effect of nitrate on the nitrogenase (C2H2-reduction) activity, growth of nodule tissue accumulation of nitrate and nitrate reductase activity in 4-weeks-old nodulated peas (Pisum sativum L.) was investigated. A relatively slow decrease of the total nitrogenase activity (mumol C2H4 per root per h), as compared with plants cultivated without nitrate, was due to both retardation of further growth of the nodule tissue and to a decrease of their specific nitrogenase activity (mumol C2H4 per gf.wt. per h). However, an absolute and pronounced decrease of both nitrogenase activities occurred only 4 or 7 d after the application of nitrate. The addition of nitrate led to its rapid accumulation in the nodule and leaf tissue with a simultaneous induction of the nitrate reductase activity. The nitrogenase activity was not completely inhibited even after a 7-d cultivation with 280 m NO3- -N in the nutrient medium and after accumulation of up to 180 ppm NO3- -Nf.wt. in the nodule tissue. The results obtained indicate that the "photosynthate deprivation" reflects competition between assimilation of nitrate and fixation of dinitrogen.

• MeSH
• časové faktory MeSH
• chemická deprese MeSH
• dusičnany aplikace a dávkování   MeSH
• dusík metabolismus   MeSH
• Fabaceae účinky léků   metabolismus   MeSH
• fotosyntéza MeSH
• kultivační média farmakologie   MeSH
• kultivační techniky MeSH
• léčivé rostliny * MeSH
• nitrátreduktasy antagonisté a inhibitory   metabolismus   MeSH
• nitrogenasa metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusičnany MeSH
• dusík MeSH
• kultivační média MeSH
• nitrátreduktasy MeSH
• nitrogenasa MeSH

Unicellular algae of genus Trebouxia are the most frequent symbiotic photobionts found in lichen species adapted to extreme environments. When lichenised, they cope well with freezing temperature of polar regions, high-mountains environments and were successfully tested in open-space experiments. Trebouxia sp. is considered potential model species for exobiological experiments. The aim of this paper is to evaluate cryoresistence of Trebouxia sp. when isolated from lichen thalli and cultivated on media. In our study, six algal strains were exposed to repeated freezing/thawing cycles. The strains of Trebouxia sp. (freshly isolated from lichen Lasallia pustulata), Trebouxia erici, Trebouxia asymmetrica, Trebouxia glomerata, Trebouxia irregularis, and Trebouxia jamesii from culture collection were cooled from 25 to -40 °C at two different rates. The strains were also shock frozen in liquid nitrogen. After repeated treatment, the strains were inoculated and cultivated on a BBM agar for 7 days. Then, cell viability was assessed as relative share of living cells. Potential quantum yield of photochemical reactions in PS II (F(V)/F(M)), and effective quantum yield of photochemical reactions in PS II (Φ(PSII)) were measured. While the slow cooling rate (0.5 °C min(-1)) did not cause any change in viability, F(V)/F(M), and Φ(PSII), the fast cooling rate (6.0 °C min(-1)) caused species-specific decrease in all parameters. The most pronounced interspecific differences in cryoresistance were found after shock freezing and consequent cultivation. While T. asymmetrica and T. jamesii exhibited low viability of living cells (18.9% and 34.7%) and full suppression of photosynthetic processes, the other strains had viability over 60%, and unaffected values of F(V)/F(M), and Φ(PSII). This indicated a high degree of cryoresistance of T. glomerata, T. erici, T. irregularis and Trebouxia sp. strains. These strains could be used for detailed investigation of underlying physiological mechanisms and as models for astrobiological tests taken in the Earth facilities.

• MeSH
• agar MeSH
• chlorofyl chemie   MeSH
• druhová specificita MeSH
• fluorescenční spektrometrie MeSH
• fotosyntéza MeSH
• fotosystém II - proteinový komplex chemie   MeSH
• fyziologická adaptace MeSH
• kryoprezervace * MeSH
• kultivační média MeSH
• lišejníky fyziologie   MeSH
• mikrobiální viabilita MeSH
• sinice klasifikace   izolace a purifikace   fyziologie   MeSH
• symbióza MeSH
• zmrazování MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• agar MeSH
• chlorofyl MeSH
• fotosystém II - proteinový komplex MeSH
• kultivační média MeSH
• photosystem II, PSII-X subunit MeSH Prohlížeč

How symbioses between bacteria and aquatic animals influence food webs in freshwater ecosystems is a fundamental question in ecology. We investigated symbiosis between a crustacean zooplankton Daphnia magna and its dominant bacterial symbiont Limnohabitans, an abundant and globally distributed freshwater Betaproteobacteria. Aposymbiotic juvenile Daphnia were prepared and exposed to any of four Limnohabitans sp. - Limnohabitans strains DM1, 2KL-3, 2KL-7 and Limnohabitans planktonicus strain II-D5, all previously found in D. magna digestive tract or culture. Re-infected Daphnia were cultured until they produced the first clutch of juveniles. Limnohabitans strain DM1 and L. planktonicus strain II-D5 successfully re-infected Daphnia through single exposure at the first instar juvenile stage. In contrast to aposymbiotic Daphnia that produced non-viable juveniles, re-infected Daphnia produced viable juveniles and increased fecundity to levels of that of symbiotic Daphnia. Re-infected Daphnia did not increase their number of eggs nor growth rates. Limnohabitans strains 2KL-7 and 2KL-3 could not recover fecundity even in multiple exposures during culture. This study shows the functional evidence demonstrating that a single bacterium Limnohabitans regulates fecundity of the consumer Daphnia through symbiosis. Our results indicated that symbiotic relationship between major bacterioplankton and zooplankton is important for maintaining the population of zooplankton in freshwater ecosystems.

• MeSH
• Betaproteobacteria genetika   růst a vývoj   izolace a purifikace   fyziologie   MeSH
• Daphnia mikrobiologie   fyziologie   MeSH
• ekosystém MeSH
• fertilita MeSH
• potravní řetězec MeSH
• sladká voda mikrobiologie   MeSH
• symbióza * MeSH
• zooplankton mikrobiologie   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Attachment theorists believe that children rely on their caregivers for protection and exploration. Due to this emphasis on independent exploration, however, the extent to which this notion of secure-base behavior is valid in societies emphasizing belongingness, such as Japan, has been questioned. By conducting an in-depth exploration of two Japanese collectivistic concepts, amae and ie, the present paper reexamines the relevance of secure-base behavior in Japan. Current discussions of amae have relied on psychoanalytic concepts that were developed in Western culture, and thus may not accurately represent Japanese parent-child relations. By examining another traditional concept of the family system, ie, this paper proposes that attachment theory is relevant in Japanese culture because children's individual competence is important to their families.

• Klíčová slova
• Amae, Attachment, Cross-culture, Japanese culture, Secure base,
• MeSH
• chování dětí etnologie   MeSH
• kojenec MeSH
• lidé MeSH
• předškolní dítě MeSH
• připoutání k objektu * MeSH
• rodina etnologie   MeSH
• vztahy mezi rodiči a dětmi etnologie   MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Japonsko etnologie   MeSH

Interactions with microorganisms might enable house dust mites (HDMs) to derive nutrients from difficult-to-digest structural proteins and to flourish in human houses. We tested this hypothesis by investigating the effects of changes in the mite culture growth and population of two HDM species on HDM microbiome composition and fitness. Growing cultures of laboratory and industrial allergen-producing populations of Dermatophagoides farinae (DFL and DFT, respectively) and Dermatophagoides pteronyssinus (DPL and DPT, respectively) were sampled at four time points. The symbiotic microorganisms of the mites were characterized by DNA barcode sequencing and quantified by qPCR using universal/specific primers. The population growth of mites and nutrient contents of mite bodies were measured and correlated with the changes in bacteria in the HDM microbiome. The results showed that both the population and culture age significantly influenced the microbiome profiles. Cardinium formed 93% and 32% of the total sequences of the DFL and DFT bacterial microbiomes, respectively, but this bacterial species was less abundant in the DPL and DPT microbiomes. Staphylococcus abundance was positively correlated with increased glycogen contents in the bodies of mites, and increased abundances of Aspergillus, Candida, and Kocuria were correlated with increased lipid contents in the bodies of mites. The xerophilic fungus Wallemia accounted for 39% of the fungal sequences in the DPL microbiome, but its abundance was low in the DPT, DFL, and DFT microbiomes. With respect to the mite culture age, we made three important observations: the mite population growth from young cultures was 5-8-fold higher than that from old cultures; specimens from old cultures had greater abundances of fungi and bacteria in their bodies; and yeasts predominated in the gut contents of specimens from young cultures, whereas filamentous mycelium prevailed in specimens from old cultures. Our results are consistent with the hypothesis that mites derive nutrients through associations with microorganisms.

• Klíčová slova
• Bacteria, Dermatophagoides farinae, Dermatophagoides pteronyssinus, Diet, Fungi, Gut, Nutrition, Symbiosis, Yeasts,
• MeSH
• Bacteria * klasifikace   MeSH
• bakteriální RNA analýza   MeSH
• druhová specificita MeSH
• fungální RNA analýza   MeSH
• houby * klasifikace   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• mikrobiota * MeSH
• populační dynamika MeSH
• Pyroglyphidae mikrobiologie   fyziologie   MeSH
• RNA ribozomální 16S analýza   MeSH
• RNA ribozomální 18S analýza   MeSH
• taxonomické DNA čárové kódování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální RNA MeSH
• fungální RNA MeSH
• RNA ribozomální 16S MeSH
• RNA ribozomální 18S MeSH

Arbuscular mycorrhizal (AM) fungi can benefit plants under environmental stress, and influence plant adaptation to warmer climates. However, very little is known about the ecology of these fungi in alpine environments. We sampled plant roots along a large fraction (1941-6150 m asl (above sea level)) of the longest terrestrial elevational gradient on Earth and used DNA metabarcoding to identify AM fungi. We hypothesized that AM fungal alpha and beta diversity decreases with increasing elevation, and that different vegetation types comprise dissimilar communities, with cultured (putatively ruderal) taxa increasingly represented at high elevations. We found that the alpha diversity of AM fungal communities declined linearly with elevation, whereas within-site taxon turnover (beta diversity) was unimodally related to elevation. The composition of AM fungal communities differed between vegetation types and was influenced by elevation, mean annual temperature, and precipitation. In general, Glomeraceae taxa dominated at all elevations and vegetation types; however, higher elevations were associated with increased presence of Acaulosporaceae, Ambisporaceae, and Claroideoglomeraceae. Contrary to our expectation, the proportion of cultured AM fungal taxa in communities decreased with elevation. These results suggest that, in this system, climate-induced shifts in habitat conditions may facilitate more diverse AM fungal communities at higher elevations but could also favour ruderal taxa.

• Klíčová slova
• alpine environment, altitudinal gradient, arbuscular mycorrhizal fungi, elevational gradient, mycorrhizal traits, the Himalayas,
• MeSH
• ekosystém MeSH
• Glomeromycota * MeSH
• kořeny rostlin mikrobiologie   MeSH
• mykorhiza * genetika   MeSH
• podnebí MeSH
• půda MeSH
• půdní mikrobiologie MeSH
• rostliny MeSH
• symbióza MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• půda MeSH

An intracellular symbiotic bacterium was isolated from the hemolymph of Triatoma infestans and cultured in an Aedes albopictus cell line. 16S ribosomal DNA sequence analysis revealed that the bacterium was a member of the gamma-3 subgroup of the class Proteobacteria, having 96.2% sequence identity with the most closely related bacterium, Arsenophonus nasoniae, the causative agent of the son-killer trait in the parasitoid wasp Nasonia vitripennis. These bacteria share morphological features and a common tissue distribution and transmission mode. The A. nasoniae-T. infestans symbiont branch represents a lineage of insect symbionts which may be capable of horizontal transmission between phylogenetically distant host insects. We propose that the intracellular symbiont from T. infestans be classified as "Candidatus Arsenophonus triatominarum." The bacterium found in the hemocytes of T. infestans is designated the type strain of this species.

• MeSH
• DNA bakterií analýza   MeSH
• elektronová mikroskopie MeSH
• fylogeneze MeSH
• gramnegativní bakterie klasifikace   genetika   ultrastruktura   MeSH
• RNA ribozomální 16S analýza   MeSH
• symbióza MeSH
• Triatoma mikrobiologie   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA bakterií MeSH
• RNA ribozomální 16S MeSH

We have investigated whether mycobiont identity and environmental conditions affect morphology and physiology of the chlorophyllous orchid: Cremastra variabilis. This species grows in a broad range of environmental conditions and associates with saprotrophic rhizoctonias including Tulasnellaceae and saprotrophic non-rhizoctonian fungi from the family Psathyrellaceae. We cultured the orchid from seeds under aseptic culture conditions and subsequently inoculated the individuals with either a Tulasnellaceae or a Psathyrellaceae isolate. We observed underground organ development of the inoculated C. variabilis plants and estimated their nutritional dependency on fungi using stable isotope abundance. Coralloid rhizome development was observed in all individuals inoculated with the Psathyrellaceae isolate, and 1-5 shoots per seedling grew from the tip of the coralloid rhizome. In contrast, individuals associated with the Tulasnellaceae isolate did not develop coralloid rhizomes, and only one shoot emerged per plantlet. In darkness, δ13C enrichment was significantly higher with both fungal isolates, whereas δ15N values were only significantly higher in plants associated with the Psathyrellaceae isolate. We conclude that C. variabilis changes its nutritional dependency on fungal symbionts depending on light availability and secondly that the identity of fungal symbiont influences the morphology of underground organs.

• Klíčová slova
• Cremastra variabilis, Coralloid rhizome, Orchidaceae, Stable isotope, Symbiotic culture,
• MeSH
• Agaricales * MeSH
• Basidiomycota * MeSH
• lidé MeSH
• mykorhiza * fyziologie   MeSH
• Orchidaceae * mikrobiologie   MeSH
• semenáček mikrobiologie   MeSH
• symbióza MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH