Search

Prokaryotes play a fundamental role in global ocean biogeochemical cycles. However, how the abundance and metabolic activity of ecologically distinct subgroups (i.e., high nucleic acid (HNA) and low nucleic acid (LNA) cells), and their regulating factors, change in response to changing marine environmental conditions remains poorly understood. Here, we delved into the time-evolving dynamic responses of the HNA and LNA prokaryotic subgroups to declining resource availability and selective grazing by protozoa by conducting a 73-day incubation experiment in a large-volume (117,000 L) macrocosm that facilitates community-level exploration. We found that the metabolic activity of the HNA subgroup was higher than that of the LNA subgroup when the macrocosm was resource replete but that the HNA subgroup declined more rapidly than the LNA subgroup as the resources became increasingly scarce, leading to a steadily increasing contribution of LNA cells to prokaryotic activity. Meanwhile, as resources in the macrocosm became limited, protozoan grazing preference shifted from the HNA to the LNA subgroup and the contributions of the LNA subgroup to the carbon flow within the macrocosm increased. The findings highlight the resilience of LNA cells in resource-limited environments, illuminate the critical role of selective grazing by protozoa in balancing distinct prokaryotic subgroups under changing resource conditions, and demonstrate the complex and adaptive interactions between protozoa and prokaryotes across diverse environmental contexts.

The evolution of the mitochondria was a significant event that gave rise to the eukaryotic lineage and most large complex life. Central to the origins of the mitochondria was an endosymbiosis between prokaryotes. Yet, despite the potential benefits that can stem from a prokaryotic endosymbiosis, their modern occurrence is exceptionally rare. While many factors may contribute to their rarity, we lack methods for estimating the extent to which they constrain the appearance of a prokaryotic endosymbiosis. Here, we address this knowledge gap by examining the role of metabolic compatibility between a prokaryotic host and endosymbiont. We use genome-scale metabolic flux models from three different collections (AGORA, KBase, and CarveMe) to assess the viability, fitness, and evolvability of potential prokaryotic endosymbioses. We find that while more than half of host-endosymbiont pairings are metabolically viable, the resulting endosymbioses have reduced growth rates compared to their ancestral metabolisms and are unlikely to gain mutations to overcome these fitness differences. In spite of these challenges, we do find that they may be more robust in the face of environmental perturbations at least in comparison with the ancestral host metabolism lineages. Our results provide a critical set of null models and expectations for understanding the forces that shape the structure of prokaryotic life.

Gram-negative bacteria have a large variety of channel-forming proteins in their outer membrane, generally referred to as porins. Some display weak voltage dependence. A similar trimeric channel former, named Triplin, displays very steep voltage dependence, rivaling that responsible for the electrical excitability of mammals, and high inter-subunit cooperativity. We report detailed insights into the molecular basis for these very unusual properties explored at the single-molecule level. By using chemical modification to reduce the charge on the voltage sensors, they were shown to be positively charged structures. Trypsin cleavage of the sensor eliminates voltage gating by cleaving the sensor. From asymmetrical addition of these reagents, the positively charged voltage sensors translocate across the membrane and are, thus, responsible energetically for the steep voltage dependence. A mechanism underlying the cooperativity was also identified. Theoretical calculations indicate that the charge on the voltage sensor can explain the rectification of the current flowing through the open pores if it is located near the pore mouth in the open state. All results support the hypothesis that one of the three subunits is oriented in a direction opposite to that of the other two. These properties make Triplin perhaps the most complex pore-forming molecular machine described to date.

This dataset contains the results of the characterisation of the prokaryotic community by flow cytometry and tritiated leucine incorporation from the MAFIA cruise (Migrants and Active Flux In the Atlantic ocean)

This dataset contains the results of the characterisation of the prokaryotic community by flow cytometry and tritiated leucine incorporation from the MAFIA cruise (Migrants and Active Flux In the Atlantic ocean)

These files contain the data described in the manuscript "A long look at short prokaryotic Argonautes "., These files contain the data described in the manuscript "A long look at short prokaryotic Argonautes ".

Marine microorganisms are involved in a variety of biogeochemical cycles and live in diverse ecological communities where they interact with each other and with other organisms to guarantee ecosystem functions. The present study focused on a shallow marine environment located in Ría de Vigo (NW, Spain), where sediment and size-fractionated plankton samples were collected from 2016 to 2018. DNA metabarcoding was used to describe the eukaryote and prokaryote composition and diversity in sediments and plankton and to depict possible associations among the most frequent and abundant organisms by co-occurrence network analysis. High eukaryote and prokaryote diversity indices were obtained in all compartments. Significant differences among eukaryote and prokaryote communities were found between sediment and plankton samples, with a high percentage of exclusive operational taxonomic units (OTUs) associated with each compartment, especially from sediment. Despite these differences, shared taxa between water and sediment were also obtained, suggesting a relatively meaningful exchange of organisms between both environmental compartments. Significant co-occurrences were mainly obtained between prokaryotes (41%), followed by eukaryotes–prokaryotes (32%) and between eukaryotes (27%). The abundant and strong positive correlations between organisms, including representatives from the sediment and the water column, suggested an essential role of biotic interactions as community-structuring factors in shallow waters where beneficial associations likely prevail. This study provides a novel approach for the detailed description of the eukaryote and prokaryote diversity and co-occurrence patterns in a shallow marine area, including both the sediment and different water-size fractions. The high diversity obtained and the detection of predominantly coexisting interactions among organisms from sediment and the overlying water column suggest a movement of species between both habitats and

Free faecal water (FFW) in equines results in pollution of the hindquarters and tail and can also involve clinical signs. Though the cause of FFW is unknown, it was hypothesized that it may involve the gut microbiota. This hypothesis was addressed as follows. First, the faecal prokaryotic community composition of horses suffering from FFW relative to healthy controls (n = 10) was compared. Second, FFW horses were treated with a standardised faecal microbiota transplantation (FMT) protocol (n = 10), followed by assessment of FFW symptom severity and faecal prokaryotic community composition over a follow-up period of 168 days. No significant differences were found in the faecal microbiota composition of FFW horses compared to healthy controls (p > 0.05). Relative to before FMT, FFW symptom severity decreased in affected horses 14 days after FMT (p = 0.02) and remained decreased for the remainder of the study (p < 0.02). However, individual animal responses to FMT varied. FMT had no effect on FFW horse faecal prokaryotic community composition in terms of alpha or beta diversity. Alpha diversity of the donor inocula used in the FMT was always lower than that of the faecal microbiota of the FFW treated horses (p < 0.001). In conclusion, whilst findings indicate FFW horses do not have an altered hindgut microbiota, some horses that received FMT had a temporary alleviation of FFW symptom severity without causing changes in the faecal microbiota. Future studies using controls are now needed to confirm the effectiveness of FMT to treat FFW.

How from high-magnitude springs fed by the Floridan aquifer system contributes hundreds of liters of water per second to rivers, creating unique lotic systems. Despite their importance as freshwater sources and their contributions to the state's major rivers, little is known about the composition and spatiotemporal variability of prokaryotic and viral communities of these spring systems or their influence on downstream river sites. At four time points throughout a year, we determined the abundance and diversity of prokaryotic and viral communities at three sites within the first-magnitude Manatee Springs system (the spring head where water emerges from the aquifer, a mixed region where the spring run ends, and a downstream site in the Suwannee River). The abundance of prokaryotes and virus-like particles increased 100-fold from the spring head to the river and few members from the head communities persisted in the river at low abundance, suggesting the springs play a minor role in seeding downstream communities. Prokaryotic and viral communities within Manatee Springs clustered by site, with seasonal variability likely driven by flow. As water flowed through the system, microbial community composition was affected by changes in physiochemical parameters and community coalescence. Evidence of species sorting and mass effects could be seen in the assemblages. Greater temporal fluctuations were observed in prokaryotic and viral community composition with increasing distance from the spring outflow, reflecting the relative stability of the groundwater environment, and comparisons to springs from prior work reaffirmed that distinct first-magnitude springs support unique communities. IMPORTANCE Prokaryotic and viral communities are central to food webs and biogeochemical processes in aquatic environments, where they help maintain ecosystem health. The Floridan aquifer system (FAS), which is the primary drinking water source for millions of people in the southeastern Unite

Deep-sea hypersaline anoxic basins are polyextreme environments in the ocean’s interior characterized by the high density of brines that prevents mixing with the overlaying seawater, generating sharp chemoclines and redoxclines up to tens of meters thick that host a high concentration of microbial communities. Yet, a fundamental understanding of how such pycnoclines shape microbial life and the associated biogeochemical processes at a fine scale, remains elusive. Here, we applied high-precision sampling of the brine–seawater transition interface in the Suakin Deep, located at 2770 m in the central Red Sea, to reveal previously undocumented fine-scale community structuring and succession of metabolic groups along a salinity gradient only 1 m thick. Metagenomic profiling at a 10-cm-scale resolution highlighted spatial organization of key metabolic pathways and corresponding microbial functional units, emphasizing the prominent role and significance of salinity and oxygen in shaping their ecology. Nitrogen cycling processes are especially affected by the redoxcline with ammonia oxidation processes being taxa and layers specific, highlighting also the presence of novel microorganisms, such as novel Thaumarchaeota and anammox, adapted to the changing conditions of the chemocline. The findings render the transition zone as a critical niche for nitrogen cycling, with complementary metabolic networks, in turn underscoring the biogeochemical complexity of deep-sea brines.

Asian dust events transport the airborne bacteria in Chinese desert regions as well as mineral particles and influence downwind area varying biological ecosystems and climate changes. However, the airborne bacterial dynamics were rarely investigated in the Gobi desert area, where dust events are highly frequent. In this study, air samplings were sequentially performed at a 2-m high above the ground at the sampling site located in desert area (Tsogt-Ovoo of Gobi desert; Mongolia 44.2304°N, 105.1700°E). During the dust event days, the bacterial cells and mineral particles increased to more than tenfold of concentrations. MiSeq sequencing targeting 16S ribosomal DNA revealed that the airborne bacteria in desert area mainly belonged to the classes Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Bacilli, Alpha-proteobacteria, Beta-proteobacteria, and Gamma-proteobacteria. The bacterial community structures were different between dust events and non-dust events. The air samples collected at the dust events indicated high abundance rates of Alpha-proteobacteria, which were reported to dominate on the leaf surfaces of plants or in the saline lake environments. After the dust events, the members of Firmicutes (Bacilli) and Bacteroidetes, which are known to form endospore and attach with coarse particles, respectively, increased their relative abundances in the air samples. Presumably, the bacterial compositions and diversities in atmosphere significantly vary during dust events, which carry some particles from grassland (phyllo-sphere), dry lake, and sand surfaces, as well as some bacterial populations such as Firmicutes and Bacteroidetes maintain in the atmosphere for longer time. © 2016 The Author(s), Embargo Period 12 months

The discovery of the numerical importance of viruses in a variety of (aquatic) ecosystems has changed our perception of their importance in microbial processes. Bacteria and Archaea undoubtedly represent the most abundant cellular life forms on Earth and past estimates of viral numbers (represented mainly by viruses infecting prokaryotes) have indicated abundances at least one order of magnitude higher than that of their cellular hosts. Such dominance has been reflected most often by the virus-to-prokaryote ratio (VPR), proposed as a proxy for the relationship between viral and prokaryotic communities. VPR values have been discussed in the literature to express viral numerical dominance (or absence of it) over their cellular hosts, but the ecological meaning and interpretation of this ratio has remained somewhat nebulous or contradictory. We gathered data from 210 publications (and additional unpublished data) on viral ecology with the aim of exploring VPR. The results are presented in three parts: the first consists of an overview of the minimal, maximal and calculated average VPR values in an extensive variety of different environments. Results indicate that VPR values fluctuate over six orders of magnitude, with variations observed within each ecosystem. The second part investigates the relationship between VPR and other indices, in order to assess whether VPR can provide insights into virus–host relationships. A positive relationship was found between VPR and viral abundance (VA), frequency of visibly infected cells (FVIC), burst size (BS), frequency of lysogenic cells (FLC) and chlorophyll a (Chl a) concentration. An inverse relationship was detected between VPR and prokaryotic abundance (PA) (in sediments), prokaryotic production (PP) and virus–host contact rates (VCR) as well as salinity and temperature. No significant relationship was found between VPR and viral production (VP), fraction of mortality from viral lysis (FMVL), viral decay rate (VDR), viral tur, SCOPUS: ar.j, info:eu-repo/semantics/published

Рассмотрено экологическое значение сине-зеленых водорослей как автотрофных организмов, обогащающих атмосферу кислородом, и как первого звена в пищевой цепи водоемов. Рассмотрены отрицательные последствия активного развития сине-зеленых водорослей для экосистем водоемов. Отмечено значение сине-зеленых водорослей в практической деятельности человека., Розглянуто екологічне значення синьо-зелених водоростей як автотрофних організмів, що збагачують атмосферу киснем, і як першої ланки в харчовому ланцюзі водоймищ. Розглянуті негативні наслідки активного розвитку синьо-зелених водоростей для екосистем водоймищ. Відзначено значення синьо-зелених водоростей в практичній діяльності людини., The ecological value of dark blue-green water-plants is considered as autotrophic organisms enriching an atmosphere by oxygen, and as the first link in the food chain of reservoirs is considered. The negative consequences of active development of dark blue-green water-plants for ecosystems of reservoirs are considered. The value of dark blue-green water-plants in practical activity of man is marked.

CRISPR-Cas are self-/nonself-discriminating systems found in prokaryotic cells. They represent a remarkable example of molecular memory that is hereditarily transmitted. Their discovery can be considered as one of the first fruits of the systematic exploration of prokaryotic genomes. Although this genomic feature was serendipitously discovered in molecular biology studies, it was the availability of multiple complete genomes that shed light about their role as a genetic immune system. Here we tell the story of how this discovery originated and was slowly and painstakingly advanced to the point of understating the biological role of what initially was just an odd genomic feature.

Background: Anesthetics mediate portions of their activity via modulation of the ?-aminobutyric acid receptor (GABAaR). Although its molecular structure remains unknown, significant progress has been made toward understanding its interactions with anesthetics via molecular modeling. Methods: The structure of the torpedo acetylcholine receptor (nAChR?), the structures of the ?4 and ?2 subunits of the human nAChR, the structures of the eukaryotic glutamate-gated chloride channel (GluCl), and the prokaryotic pH-sensing channels, from Gloeobacter violaceus and Erwinia chrysanthemi, were aligned with the SAlign and 3DMA algorithms. A multiple sequence alignment from these structures and those of the GABAaR was performed with ClustalW. The Modeler and Rosetta algorithms independently created three-dimensional constructs of the GABAaR from the GluCl template. The CDocker algorithm docked a congeneric series of propofol derivatives into the binding pocket and scored calculated binding affinities for correlation with known GABAaR potentiation EC50s. Results: Multiple structure alignments of templates revealed a clear consensus of residue locations relevant to anesthetic effects except for torpedo nAChR. Within the GABAaR models generated from GluCl, the residues notable for modulating anesthetic action within transmembrane segments 1, 2, and 3 converged on the intersubunit interface between ? and ? subunits. Docking scores of a propofol derivative series into this binding site showed strong linear correlation with GABAaR potentiation EC50. Conclusion: Consensus structural alignment based on homologous templates revealed an intersubunit anesthetic binding cavity within the transmembrane domain of the GABAaR, which showed a correlation of ligand docking scores with experimentally measured GABAaR potentiation., QC 20140121

ARA 13-14 Lecture 2 - Structure and function of the prokaryotic cell. NO IMAGES.

Background: In addition to vertical transmission, organisms can also acquire genes from other distantly related species or from their extra-chromosomal elements (plasmids and viruses) via horizontal gene transfer (HGT). It has been suggested that phages represent substantial forces in prokaryotic evolution. In eukaryotes, retroviruses, which can integrate into host genome as an obligate step in their replication strategy, comprise approximately 8% of the human genome. Unlike retroviruses, few members of other virus families are known to transfer genes to host genomes. Results: Here we performed a systematic search for sequences related to circular single-stranded DNA (ssDNA) viruses in publicly available eukaryotic genome databases followed by comprehensive phylogenetic analysis. We conclude that the replication initiation protein (Rep)-related sequences of geminiviruses, nanoviruses and circoviruses have been frequently transferred to a broad range of eukaryotic species, including plants, fungi, animals and protists. Some of the transferred viral genes were conserved and expressed, suggesting that these genes have been coopted to assume cellular functions in the host genomes. We also identified geminivirus-like and parvovirus-like transposable elements in genomes of fungi and lower animals, respectively, and thereby provide direct evidence that eukaryotic transposons could derive from ssDNA viruses. Conclusions: Our discovery extends the host range of circular ssDNA viruses and sheds light on the origin and evolution of these viruses. It also suggests that ssDNA viruses act as an unforeseen source of genetic innovation in their hosts. © 2011 Liu et al; licensee BioMed Central Ltd.

The reduced forms of NAD and NADP, two major nucleotides playing a central role in metabolism, are continuously damaged by enzymatic or heat-dependent hydration. We report the molecular identification of the eukaryotic dehydratase that repairs these nucleotides and show that this enzyme (Carkd in mammals, YKL151C in yeast) catalyzes the dehydration of the S form of NADHX and NADPHX, at the expense of ATP, which is converted to ADP. Surprisingly, the Escherichia coli homolog, YjeF, a bidomain protein, catalyzes a similar reaction, but using ADP instead of ATP. The latter reaction is ascribable to the C-terminal domain of YjeF. This represents an unprecedented example of orthologous enzymes using either ADP or ATP as phosphoryl donor.We also show that eukaryotic proteins homologous to the N-terminal domain of YjeF (apolipoprotein A-1-binding protein (AIBP) in mammals, YNL200C in yeast) catalyze the epimerization of the S and R forms of NAD(P)HX, thereby allowing, in conjunction with the energy-dependent dehydratase, the repair of both epimers of NAD(P)HX. Both enzymes are very widespread in eukaryotes, prokaryotes, and archaea, which together with theADPdependence of the dehydratase in some species indicates the ancient origin of this repair system. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

In DNA replication, the antiparallel nature of the parental duplex imposes certain constraints on the activity of the DNA polymerases that synthesize new DNA. The leading-strand polymerase advances in a continuous fashion, but the lagging-strand polymerase is forced to restart at short intervals. In several prokaryotic systems studied so far, this problem is solved by the formation of a loop in the lagging strand of the replication fork to reorient the lagging-strand DNA polymerase so that it advances in parallel with the leading-strand polymerase. The replication loop grows and shrinks during each cycle of Okazaki fragment synthesis. The timing of Okazaki fragment synthesis and loop formation is determined by a subtle interplay of enzymatic activities at the fork. Recent developments in single-molecule techniques have enabled the direct observation of these processes and have greatly contributed to a better understanding of the dynamic nature of the replication fork. Here, we will review recent experimental advances, present the current models, and discuss some of the exciting developments in the field. 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Background: There are a growing number of next-generation sequencing technologies. At present, the most cost-effective options also produce the shortest reads. However, even for prokaryotes, there is uncertainty concerning the utility of these technologies for the de novo assembly of complete genomes. This reflects an expectation that short reads will be unable to resolve small, but presumably abundant, repeats. Methodology/Principal Findings: Using a simple model of repeat assembly, we develop and test a technique that, for any read length, can estimate the occurrence of unresolvable repeats in a genome, and thus predict the number of gaps that would need to be closed to produce a complete sequence. We apply this technique to 818 prokaryote genome sequences. This provides a quantitative assessment of the relative performance of various lengths. Notably, unpaired reads of only 150nt can reconstruct approximately 50% of the analysed genomes with fewer than 96 repeat-induced gaps. Nonetheless, there is considerable variation amongst prokaryotes. Some genomes can be assembled to near contiguity using very short reads while others require much longer reads. Conclusions: Given the diversity of prokaryote genomes, a sequencing strategy should be tailored to the organism under study. Our results will provide researchers with a practical resource to guide the selection of the appropriate read length. 2010 Cahill et al.

Bacteria had remained undefined when, in 1962, Roger Y. Stanier and C.B. van Niel published their famed paper “The concept of a bacterium.” The articulation of the prokaryote–eukaryote dichotomy was a vital moment in the history of biology. This article provides a brief overview of the context in which the prokaryote concept was successfully launched in the 1960s, and what it was meant to connote. Two concepts were initially distinguished within the prokaryote– eukaryote dichotomy at that time. One was organizational and referred to comparative cell structure; the other was phylogenetic and referred to a “natural” classification. Here, I examine how the two concepts became inseparable; how the prokaryotes came to signify a monophyletic group that preceded the eukaryotes, and how this view remained unquestioned for 15 years, until the birth of molecular evolutionary biology and coherent methods for bacteria phylogenetics based on 16S rRNA. Today, while microbial phylogeneticists generally agree that the prokaryote is a polyphyletic group, there is no agreement on whether the term should be maintained in an organizational sense. [Int Microbiol 2006; 9(3):163-172]

Light-dependent disulphide/dithiol exchange catalysed by thioredoxin is a classical example of redox regulation of chloroplast enzymes. Recent proteome studies have mapped thioredoxin target proteins in all chloroplast compartments ranging from the envelope to the thylakoid lumen. Progress in the methodologies has made it possible to identify which cysteine residues interact with thioredoxin and to tackle membrane-bound thioredoxin targets. To date, more than hundred targets of thioredoxin and glutaredoxin have been found in plastids from Arabidopsis, spinach, poplar and Chlamydomonas reinhardtii. Thioredoxin-mediated redox control appears to be a feature of the central pathways for assimilation and storage of carbon, sulphur and nitrogen, as well as for translation and protein folding. Cyanobacteria are oxygenic photosynthetic prokaryotes, which presumably share a common ancestor with higher plant plastids. As in chloroplasts, cyanobacterial thioredoxins receive electrons from the photosynthetic electron transport, and thioredoxin-targeted proteins are therefore highly interesting in the context of acclimation of these organisms to their environment. Studies of the unicellular model cyanobacterium Synechocystis sp. PCC 6803 revealed 77 thioredoxin target proteins. Notably, the functions of all these thioredoxin targets highlight essentially the same processes as those described in chloroplasts suggesting that thioredoxin-mediated redox signalling is equally significant in oxygenic photosynthetic prokaryotes and eukaryotes.

Background: Clone-based microarrays, on which each spot represents a random genomic fragment, are a good alternative to open reading frame-based microarrays, especially for microorganisms for which the complete genome sequence is not available. Since the generation of a genomic DNA library is a random process, it is beforehand uncertain which genes are represented. Nevertheless, the genome coverage of such an array, which depends on different variables like the insert size and the number of clones in the library, can be predicted by mathematical approaches. When applying the classical formulas that determine the probability that a certain sequence is represented in a DNA library at the nucleotide level, massive amounts of clones would be necessary to obtain a proper coverage of the genome. Results: This paper describes the development of two complementary equations for determining the genome coverage at the gene level. The first equation predicts the fraction of genes that is represented on the array in a detectable way and cover at least a set part (the minimal insert coverage) of the genomic fragment by which these enes are represented. The higher this minimal insert coverage, the larger the chance that changes in expression of a specific gene can be detected and attributed to that gene. The second equation predicts the fraction of genes that is represented in spots on the array that only represent genes from a single transcription unit, which information can be interpreted in a quantitative way. Conclusion: Validation of these equations shows that they form reliable tools supporting optimal design of prokaryotic clone-based microarrays. © 2005 Pieterse et al; licensee BioMed Central Ltd.

Histone deacetylases (HDACs) modify core histones and participate in large regulatory complexes that both suppress and enhance transcription. Recent studies indicate that some HDACs can act on non-histone proteins as well. Interest in these enzymes is growing because HDAC inhibitors appear to be promising therapeutic agents against cancer and a variety of other diseases. Thus far, 11 members of the HDAC family have been identified in humans, but few have been characterized in detail. To better define the biological function of these proteins, make maximal use of studies performed in other systems, and assist in drug development efforts, we have performed a phylogenetic analysis of all HDAC-related proteins in all fully sequenced free-living organisms. Previous analyses have divided non-sirtuin HDACs into two groups, classes 1 and 2. We find that HDACs can be divided into three equally distinct groups: class 1, class 2, and a third class consisting of proteins related to the recently identified human HDAC11 gene. We term this novel group "class 4" to distinguish it from the unrelated "class 3" sirtuin deacetylases. Analysis of gene duplication events indicates that the common ancestor of metazoan organisms contained two class 1, two class 2, and a single class 4 HDAC. Examination of HDAC characteristics in light of these evolutionary relationships leads to functional predictions, among them that self-association is common among HDAC proteins. All three HDAC classes (including class 4) exist in eubacteria. Phylogenetic analysis of bacterial HDAC relatives suggests that all three HDAC classes precede the evolution of histone proteins and raises the possibility that the primary activity of some "histone deacetylase" enzymes is directed against non-histone substrates., QC 20141211

For many years, it has been understood that protein phosphorylation-dephosphorylation constitutes one of the most ubiquitous mechanisms for controlling the functional properties of proteins. Although originally believed to be a eukaryotic phenomenon, protein phosphorylation is now known to occur in all three domains of life Eukarya, Bacteria, and Archaea. Very little is known, however, concerning the origins and evolution of protein phosphorylation-dephosphorylation. Knowledge of the structure and properties of the protein kinases resident in the members of the Archaea represents a key piece of this puzzle. The extreme acidothermophilic archaeon, Sulfolobus solfataricus, exhibits a membrane-associated protein kinase activity. Solubilization of the kinase activity requires the presence of detergent such as Triton X-100 or octyl glucoside, indicating its activity reside in an integral membrane protein. This protein kinase utilizes purine nucleotides as phosphoryl donors in vitro with a requirement for a divalent metal ion cofactor, favoring Mn⁺². A preference for NTPs over NDPs and for adenyl nucleotides over the analogous guanyl nucleotides was observed. The enzyme appears to be a glycoprotein that displays catalytic activity on SDS-PAGE corresponding to a molecular mass of ≈67 kDa, as well as an apparent molecular mass of –125 kDa on a gel filtration column. Challenged with several exogenous substrates revealed the protein kinase to be relatively selective. Only casein, reduced carboxyamidomethylated and maleylated lysozyme (RCM lysozyme), histone H4 proved, and a peptide modeled after myosin light chains (KKRAARATSNVFA) were phosphorylated to appreciable levels in vitro. All of the aforementioned substrates were phosphorylated on threonine, while histone H4 was phosphorylated on serine as well. When the phosphoacceptor threonine in the MLC peptide was substituted with serine an appreciable decrease in phosphorylation was noted

260 sequences of tRNA are compared, after their classification into six categories: prokaryotic (83 sequences) and eukaryotic (83 sequences) elongators, prokaryotic (10 sequences) and eukaryotic (11 sequences), initiators, lower eukaryotic mitochondrial tRNA (53 sequences) and archaebacterial tRNA (20 sequences). Beside the presence of invariable and semi-invariable positions in tRNA, non-random base distribution in almost all positions is also evident; most of them being characteristic of each class of tRNA. Therefore, during evolution it would seem that selectional pressures do act in so called variable positions as well as invariant positions of tRNA molecules. Results are discussed in relation to possible restrictions depending on functional and/or structural constraints of tRNA. © 1982 Masson, Paris., SCOPUS: re.j, info:eu-repo/semantics/published

Tato bakalářská práce se zabývá metodami predikce genů v prokaryotických organismech. V první části je popsána prokaryotická buňka včetně genomu, exprese genetické informace a rozdělení metod pro predikci genů. Dále je zde uveden popis tří vybraných softwarů, které predikci provádějí. V praktické části je rozebráno testování softwarů a vyhodnocení jejich účinnosti na daném genomu. Nakonec je zde popsán vytvořený program pro hledání genů a jsou zde uvedeny výsledky jeho účinnosti., This bachelor thesis deals with methods of gene prediction in prokaryotic genomes. First part of the thesis introduces prokaryotic cell, its genome, expression of genetic information and methods for gene prediction. Following part describes three software products for gene prediction. Chosen software was tested against specific genome and next chapter presents obtained results. The last part describes program called Gene_finder and its results.

Tato bakalářská práce se zabývá metodami predikce genů v prokaryotických organismech. V první části je popsána prokaryotická buňka včetně genomu, exprese genetické informace a rozdělení metod pro predikci genů. Dále je zde uveden popis tří vybraných softwarů, které predikci provádějí. V praktické části je rozebráno testování softwarů a vyhodnocení jejich účinnosti na daném genomu. Nakonec je zde popsán vytvořený program pro hledání genů a jsou zde uvedeny výsledky jeho účinnosti., This bachelor thesis deals with methods of gene prediction in prokaryotic genomes. First part of the thesis introduces prokaryotic cell, its genome, expression of genetic information and methods for gene prediction. Following part describes three software products for gene prediction. Chosen software was tested against specific genome and next chapter presents obtained results. The last part describes program called Gene_finder and its results.

Tato bakalářská práce se zabývá metodami predikce genů v prokaryotických organismech. V první části je popsána prokaryotická buňka včetně genomu, exprese genetické informace a rozdělení metod pro predikci genů. Dále je zde uveden popis tří vybraných softwarů, které predikci provádějí. V praktické části je rozebráno testování softwarů a vyhodnocení jejich účinnosti na daném genomu. Nakonec je zde popsán vytvořený program pro hledání genů a jsou zde uvedeny výsledky jeho účinnosti., This bachelor thesis deals with methods of gene prediction in prokaryotic genomes. First part of the thesis introduces prokaryotic cell, its genome, expression of genetic information and methods for gene prediction. Following part describes three software products for gene prediction. Chosen software was tested against specific genome and next chapter presents obtained results. The last part describes program called Gene_finder and its results.

Tato bakalářská práce se zabývá metodami predikce genů v prokaryotických organismech. V první části je popsána prokaryotická buňka včetně genomu, exprese genetické informace a rozdělení metod pro predikci genů. Dále je zde uveden popis tří vybraných softwarů, které predikci provádějí. V praktické části je rozebráno testování softwarů a vyhodnocení jejich účinnosti na daném genomu. Nakonec je zde popsán vytvořený program pro hledání genů a jsou zde uvedeny výsledky jeho účinnosti., This bachelor thesis deals with methods of gene prediction in prokaryotic genomes. First part of the thesis introduces prokaryotic cell, its genome, expression of genetic information and methods for gene prediction. Following part describes three software products for gene prediction. Chosen software was tested against specific genome and next chapter presents obtained results. The last part describes program called Gene_finder and its results.

Tato bakalářská práce se zabývá metodami predikce genů v prokaryotických organismech. V první části je popsána prokaryotická buňka včetně genomu, exprese genetické informace a rozdělení metod pro predikci genů. Dále je zde uveden popis tří vybraných softwarů, které predikci provádějí. V praktické části je rozebráno testování softwarů a vyhodnocení jejich účinnosti na daném genomu. Nakonec je zde popsán vytvořený program pro hledání genů a jsou zde uvedeny výsledky jeho účinnosti., This bachelor thesis deals with methods of gene prediction in prokaryotic genomes. First part of the thesis introduces prokaryotic cell, its genome, expression of genetic information and methods for gene prediction. Following part describes three software products for gene prediction. Chosen software was tested against specific genome and next chapter presents obtained results. The last part describes program called Gene_finder and its results.

Tato bakalářská práce se zabývá metodami predikce genů v prokaryotických organismech. V první části je popsána prokaryotická buňka včetně genomu, exprese genetické informace a rozdělení metod pro predikci genů. Dále je zde uveden popis tří vybraných softwarů, které predikci provádějí. V praktické části je rozebráno testování softwarů a vyhodnocení jejich účinnosti na daném genomu. Nakonec je zde popsán vytvořený program pro hledání genů a jsou zde uvedeny výsledky jeho účinnosti., This bachelor thesis deals with methods of gene prediction in prokaryotic genomes. First part of the thesis introduces prokaryotic cell, its genome, expression of genetic information and methods for gene prediction. Following part describes three software products for gene prediction. Chosen software was tested against specific genome and next chapter presents obtained results. The last part describes program called Gene_finder and its results.

Tato bakalářská práce se zabývá metodami predikce genů v prokaryotických organismech. V první části je popsána prokaryotická buňka včetně genomu, exprese genetické informace a rozdělení metod pro predikci genů. Dále je zde uveden popis tří vybraných softwarů, které predikci provádějí. V praktické části je rozebráno testování softwarů a vyhodnocení jejich účinnosti na daném genomu. Nakonec je zde popsán vytvořený program pro hledání genů a jsou zde uvedeny výsledky jeho účinnosti., This bachelor thesis deals with methods of gene prediction in prokaryotic genomes. First part of the thesis introduces prokaryotic cell, its genome, expression of genetic information and methods for gene prediction. Following part describes three software products for gene prediction. Chosen software was tested against specific genome and next chapter presents obtained results. The last part describes program called Gene_finder and its results.

Tato bakalářská práce se zabývá metodami predikce genů v prokaryotických organismech. V první části je popsána prokaryotická buňka včetně genomu, exprese genetické informace a rozdělení metod pro predikci genů. Dále je zde uveden popis tří vybraných softwarů, které predikci provádějí. V praktické části je rozebráno testování softwarů a vyhodnocení jejich účinnosti na daném genomu. Nakonec je zde popsán vytvořený program pro hledání genů a jsou zde uvedeny výsledky jeho účinnosti., This bachelor thesis deals with methods of gene prediction in prokaryotic genomes. First part of the thesis introduces prokaryotic cell, its genome, expression of genetic information and methods for gene prediction. Following part describes three software products for gene prediction. Chosen software was tested against specific genome and next chapter presents obtained results. The last part describes program called Gene_finder and its results.