Plant-plant interactions are major determinants of the dynamics of terrestrial ecosystems. There is a long tradition in the study of these interactions, their mechanisms and their consequences using experimental, observational and theoretical approaches. Empirical studies overwhelmingly focus at the level of species pairs or small sets of species. Although empirical data on these interactions at the community level are scarce, such studies have gained pace in the last decade. Studying plant-plant interactions at the community level requires knowledge of which species interact with which others, so an ecological networks approach must be incorporated into the basic toolbox of plant community ecology. The concept of recruitment networks (RNs) provides an integrative framework and new insights for many topics in the field of plant community ecology. RNs synthesise the set of canopy-recruit interactions in a local plant assemblage. Canopy-recruit interactions describe which ("canopy") species allow the recruitment of other species in their vicinity and how. Here we critically review basic concepts of ecological network theory as they apply to RNs. We use RecruitNet, a recently published worldwide data set of canopy-recruit interactions, to describe RN patterns emerging at the interaction, species, and community levels, and relate them to different abiotic gradients. Our results show that RNs can be sampled with high accuracy. The studies included in RecruitNet show a very high mean network completeness (95%), indicating that undetected canopy-recruit pairs must be few and occur very infrequently. Across 351,064 canopy-recruit pairs analysed, the effect of the interaction on recruitment was neutral in an average of 69% of the interactions per community, but the remaining interactions were positive (i.e. facilitative) five times more often than negative (i.e. competitive), and positive interactions had twice the strength of negative ones. Moreover, the frequency and strength of facilitation increases along a climatic aridity gradient worldwide, so the demography of plant communities is increasingly strongly dependent on facilitation as aridity increases. At network level, species can be ascribed to four functional types depending on their position in the network: core, satellite, strict transients and disturbance-dependent transients. This functional structure can allow a rough estimation of which species are more likely to persist. In RecruitNet communities, this functional structure most often departs from random null model expectation and could allow on average the persistence of 77% of the species in a local community. The functional structure of RNs also varies along the aridity gradient, but differently in shrubland than in forest communities. This variation suggests an increase in the probability of species persistence with aridity in forests, while such probability remains roughly constant along the gradient in shrublands. The different functional structure of RNs between forests and shrublands could contribute to explaining their co-occurrence as alternative stable states of the vegetation under the same climatic conditions. This review is not exhaustive of all the topics that can be addressed using the framework of RNs, but instead aims to present some of the interesting insights that it can bring to the field of plant community ecology.

• Klíčová slova
• canopy service, ecological networks, facilitation, interaction strength, plant–plant interactions, recruitment niche, replacement networks, sapling bank, stress gradient hypothesis, strongly connected components,
• Publikační typ
• časopisecké články MeSH

The main advantage of the use of electrochemical methods is that the object studied is under conditions very close to the natural ones. Next advantage is that the same information about the sample can be received with lower costs than other methods. The electrode double layer impedance measurement is effective electrochemical method of the study of interaction of the substances on electrode surface. It is much more sensitive on adsorption processes than other electrochemical methods. After the mathematical evaluation of the results of the electrode double layer impedance measurements it was found, that the adsorption energies of xanthine are much higher than those of adenine and for hypoxanthine are close to adenine. This result could be connected with the role of these two adenine metabolites in nucleic acids. The measurements in the solutions, containing different methyl derivatives of xanthine showed that the adsorption behaviour of every substance is strongly dependent on the position of the methyl group in the molecule. From the dependence of the electrode double layer impedance on the potential and frequency in the solution containing 3'-azido-2'3'-dideoxythymidine (AZT) it was found, that under conditions studied a reduction process occurs in the sample near-IV vs. AgCl. The adsorption behaviour of AZT is the same as that of thymidine both at room temperature and at lower ones (near 0 degree C). The measurement of the electrode double layer impedance is the sensitive method for the study of the properties of the nucleic acids components that could be used in the field of new antiviral agents development.

• MeSH
• adenin analogy a deriváty   farmakokinetika   MeSH
• adsorpce MeSH
• elektrická impedance MeSH
• elektrochemie MeSH
• elektrody MeSH
• nukleosidy farmakokinetika   MeSH
• xanthiny farmakokinetika   MeSH
• zidovudin farmakokinetika   MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenin MeSH
• nukleosidy MeSH
• xanthiny MeSH
• zidovudin MeSH

Cholesterol is not only a major component of the cell membrane, but also plays an important role in a wide range of biological processes and pathologies. It is therefore crucial to develop appropriate tools for visualizing intracellular cholesterol transport. Here, we describe new cationic analogues of BODIPY-Cholesterol (TopFluor-Cholesterol, TF-Chol), which combine a positive charge on the sterol side chain and a BODIPY group connected via a C-4 linker. In contrast to TF-Chol, the new analogues TF-1 and TF-3 possessing acetyl groups on the A ring (C-3 position on steroid) internalized much faster and displayed slightly different levels of intracellular localization. Their applicability for cholesterol monitoring was indicated by the fact that they strongly label compartments with accumulated cholesterol in cells carrying a mutation of the Niemann-Pick disease-associated cholesterol transporter, NPC1.

• Klíčová slova
• Cholesterol transport, Fluorescence imaging, Sterol, TopFluor cholesterol analogues, Trafficking disorders,
• MeSH
• biologický transport MeSH
• buněčné linie MeSH
• cholesterol analogy a deriváty   analýza   chemická syntéza   metabolismus   MeSH
• lidé MeSH
• optické zobrazování MeSH
• sloučeniny boru analýza   chemická syntéza   chemie   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene MeSH Prohlížeč
• cholesterol MeSH
• sloučeniny boru MeSH

Rising temperatures in the Arctic can affect soil organic matter (SOM) decomposition directly and indirectly, by increasing plant primary production and thus the allocation of plant-derived organic compounds into the soil. Such compounds, for example root exudates or decaying fine roots, are easily available for microorganisms, and can alter the decomposition of older SOM ("priming effect"). We here report on a SOM priming experiment in the active layer of a permafrost soil from the central Siberian Arctic, comparing responses of organic topsoil, mineral subsoil, and cryoturbated subsoil material (i.e., poorly decomposed topsoil material subducted into the subsoil by freeze-thaw processes) to additions of 13C-labeled glucose, cellulose, a mixture of amino acids, and protein (added at levels corresponding to approximately 1% of soil organic carbon). SOM decomposition in the topsoil was barely affected by higher availability of organic compounds, whereas SOM decomposition in both subsoil horizons responded strongly. In the mineral subsoil, SOM decomposition increased by a factor of two to three after any substrate addition (glucose, cellulose, amino acids, protein), suggesting that the microbial decomposer community was limited in energy to break down more complex components of SOM. In the cryoturbated horizon, SOM decomposition increased by a factor of two after addition of amino acids or protein, but was not significantly affected by glucose or cellulose, indicating nitrogen rather than energy limitation. Since the stimulation of SOM decomposition in cryoturbated material was not connected to microbial growth or to a change in microbial community composition, the additional nitrogen was likely invested in the production of extracellular enzymes required for SOM decomposition. Our findings provide a first mechanistic understanding of priming in permafrost soils and suggest that an increase in the availability of organic carbon or nitrogen, e.g., by increased plant productivity, can change the decomposition of SOM stored in deeper layers of permafrost soils, with possible repercussions on the global climate.

• Klíčová slova
• Organic matter decomposition, Permafrost, Phospholipid fatty acid (PLFA), Priming, Tundra,
• Publikační typ
• časopisecké články MeSH

Non-inflammatory alopecia is a frequent skin problem in dogs, causing damaged coat integrity and compromised appearance of affected individuals. In this study, we examined the Cesky Fousek breed, which displays atypical recurrent flank alopecia (aRFA) at a high frequency. This type of alopecia can be quite severe and is characterized by seasonal episodes of well demarcated alopecic areas without hyperpigmentation. The genetic component responsible for aRFA remains unknown. Thus, here we aimed to identify variants involved in aRFA using a combination of histological, genomic, and transcriptomic data. We showed that aRFA is histologically similar to recurrent flank alopecia, characterized by a lack of anagen hair follicles and the presence of severely shortened telogen or kenogen hair follicles. We performed a genome-wide association study (GWAS) using 216 dogs phenotyped for aRFA and identified associations on chromosomes 19, 8, 30, 36, and 21, highlighting 144 candidate genes, which suggests a polygenic basis for aRFA. By comparing the skin cell transcription pattern of six aRFA and five control dogs, we identified 236 strongly differentially expressed genes (DEGs). We showed that the GWAS genes associated with aRFA are often predicted to interact with DEGs, suggesting their joint contribution to the development of the disease. Together, these genes affect four major metabolic pathways connected to aRFA: collagen formation, muscle structure/contraction, lipid metabolism, and the immune system.

• Klíčová slova
• Cesky Fousek, GWAS, RNA-seq, atypical recurrent flank alopecia, canine alopecia, differential gene expression, dog, skin biopsies,
• MeSH
• alopecie genetika   patologie   veterinární   MeSH
• celogenomová asociační studie * MeSH
• kůže patologie   MeSH
• psi MeSH
• transkriptom * genetika   MeSH
• vlasový folikul MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chronic periodontitis (CP), an infectious disease resulting in inflammation within the periodontal tissue, is the main cause of adult tooth loss. CP is a multi-factorial disorder and the interaction between multiple genetic and environmental factors results in the manifestation of this disease. Recent researches in periodontitis has focused on cytokine gene polymorphisms that play important role in periodontal inflammation, but few studies investigated histological change that occur during CP in the supporting tissue of teeth. The aims of this study were to investigate the association of IFN-γ +874 A/T polymorphisms and quantitative parameters of interdental gingiva in CP patients. The study samples were interdental gingiva biopsies from 60 individuals including 38 patients and 22 healthy subjects. After determination of IFN-γ +874 A/T gene polymorphism by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR), patients were divided in three subgroups: 10 AA, 18 AT and 10 TT. After slides preparation, quantitative parameters were estimated by Cavalieri's point-counting method. Statistical analyses were performed using Mann-Whitney and Kruskal-Wallis test to compare differences between groups. The volume density (Vv) of epithelium, connective tissue and its components were significantly different between the control and CP groups (P<0.05). Statistically significant differences in the Vv of collagenous and non-collagenous matrix of interdental gingiva between AA, AT and TT groups were found (P<0.05). Result of present study shows that IFN-γ +874 A/T is strongly associated with some quantitative parameters of connective tissue constituents of interdental papilla in CP patients.

• Klíčová slova
• Chronic periodontitis, Genetic, Gingiva, Interferon-gamma, Polymorphism,
• MeSH
• biopsie MeSH
• chronická parodontitida genetika   MeSH
• dospělí MeSH
• genetická predispozice k nemoci MeSH
• genotyp MeSH
• gingiva patologie   MeSH
• interferon gama genetika   MeSH
• lidé MeSH
• polymerázová řetězová reakce MeSH
• polymorfismus genetický genetika   MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• interferon gama MeSH

Interneuronal connections are an important component of the integration circuits of the hippocampus. They are formed mostly postnatally, i.e. in a phase when their development can be strongly influenced by external environmental factors. In model postnatal hypoxia, a morphometric analysis showed reduction of the number of dendritic segments (chiefly 3rd order segments) in 18-day-old rats. The total length of the dendrites was unaltered, but mean segment length increased. Interneuron density in the experimental animals was higher, especially in the stratum radiatum, but pyramidal cell density was lower than in the controls. These findings are evidence that hypoxia has a complex effect on the microstructure of the hippocampus and that, in the long run, it can lead to impairment of the balance of the elementary processes of excitation and inhibition.

• MeSH
• buněčná diferenciace MeSH
• buněčné dělení MeSH
• dendrity ultrastruktura   MeSH
• hipokampus růst a vývoj   patologie   MeSH
• hypoxie patologie   MeSH
• inbrední kmeny potkanů MeSH
• interneurony patologie   MeSH
• krysa rodu Rattus MeSH
• počet buněk MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Recent fMRI resting-state findings show aberrant functional connectivity within somatomotor network (SMN) in schizophrenia. Moreover, functional connectivity aberrations of the motor system are often reported to be related to the severity of psychotic symptoms. Thus, it is important to validate those findings and confirm their relationship with psychopathology. Therefore, we decided to take an entirely data-driven approach in our fMRI resting-state study of 30 chronic schizophrenia outpatients and 30 matched control subjects. We used independent component analysis (ICA), dual regression, and seed-based connectivity analysis. We found reduced functional connectivity within SMN in schizophrenia patients compared to controls and SMN hypoconnectivity with the cerebellum in schizophrenia patients. The latter was strongly correlated with the severity of alogia, one of the main psychotic symptoms, i.e. poverty of speech and reduction in spontaneous speech,. Our results are consistent with the recent knowledge about the role of the cerebellum in cognitive functioning and its abnormalities in psychiatric disorders, e.g. schizophrenia. In conclusion, the presented results, for the first time clearly showed the involvement of the cerebellum hypoconnectivity with SMN in the persistence and severity of alogia symptoms in schizophrenia.

• Klíčová slova
• Cerebellum, Negative symptoms, Schizophrenia, Somatomotor network, fMRI,
• MeSH
• afázie patofyziologie   diagnostické zobrazování   etiologie   patologie   MeSH
• chronická nemoc MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• mozeček * diagnostické zobrazování   patofyziologie   MeSH
• nervová síť diagnostické zobrazování   patofyziologie   MeSH
• nervové dráhy patofyziologie   diagnostické zobrazování   MeSH
• schizofrenie * diagnostické zobrazování   patofyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Supramolecular structures, such as micelles, liposomes, polymerosomes or dendrimerosomes, are widely studied and used as drug delivery systems. The behavior of amphiphilic building blocks strongly depends on their spatial distribution and shape of polar and nonpolar component. This report is focused on the development of new versatile synthetic protocols for amphiphilic carbosilane dendrons (amp-CS-DDNs) capable of self-assembly to regular micelles and other supramolecular objects. The presented strategy enables the fine modification of amphiphilic structure in several ways and also enables the facile connection of a desired functionality. DLS experiments demonstrated correlations between structural parameters of amp-CS-DDNs and the size of formed nanoparticles. For detailed information about the organization and spatial distribution of amp-CS-DDNs assemblies, computer simulation models were studied by using molecular dynamics in explicit water.

• Klíčová slova
• DLS, amphiphiles, carbosilane, computer modeling, dendrons, micelles, molecular dynamics, zeta potential,
• MeSH
• anthraceny chemie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• micely MeSH
• nanočástice chemie   MeSH
• počítačová simulace MeSH
• silany chemie   MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• anthraceny MeSH
• carbosilane MeSH Prohlížeč
• dendron MeSH Prohlížeč
• micely MeSH
• silany MeSH
• voda MeSH

The great ethnolinguistic diversity found today in mainland Southeast Asia (MSEA) reflects multiple migration waves of people in the past. Maritime trading between MSEA and India was established at the latest 300 BCE, and the formation of early states in Southeast Asia during the first millennium CE was strongly influenced by Indian culture, a cultural influence that is still prominent today. Several ancient Indian-influenced states were located in present-day Thailand, and various populations in the country are likely to be descendants of people from those states. To systematically explore Indian genetic heritage in MSEA populations, we generated genome-wide SNP data (using the Affymetrix Human Origins array) for 119 present-day individuals belonging to 10 ethnic groups from Thailand and co-analyzed them with published data using PCA, ADMIXTURE, and methods relying on f-statistics and on autosomal haplotypes. We found low levels of South Asian admixture in various MSEA populations for whom there is evidence of historical connections with the ancient Indian-influenced states but failed to find this genetic component in present-day hunter-gatherer groups and relatively isolated groups from the highlands of Northern Thailand. The results suggest that migration of Indian populations to MSEA may have been responsible for the spread of Indian culture in the region. Our results also support close genetic affinity between Kra-Dai-speaking (also known as Tai-Kadai) and Austronesian-speaking populations, which fits a linguistic hypothesis suggesting cladality of the two language families.

• MeSH
• Asijci genetika   MeSH
• etnicita genetika   MeSH
• genetická variace genetika   MeSH
• haplotypy genetika   MeSH
• jazyk (prostředek komunikace) MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• lidé MeSH
• populační genetika metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Geografické názvy
• Indie etnologie   MeSH
• jihovýchodní Asie etnologie   MeSH
• Thajsko etnologie   MeSH