Genes, rRNA: Genes, found in both prokaryotes and eukaryotes, which are transcribed to produce the RNA which is incorporated into RIBOSOMES. Prokaryotic rRNA genes are usually found in OPERONS dispersed throughout the GENOME, whereas eukaryotic rRNA genes are clustered, multicistronic transcriptional units.RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.DNA, Ribosomal: DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.RNA, Ribosomal: The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)rRNA Operon: Genetic loci which direct transcription of ribosomal RNA in bacterial operons. They are designated rrnB, rrnC, rrnD, etc. according to the structural position of the transcription unit in the DNA sequence.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.RNA, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.RNA, Ribosomal, 23S: Constituent of 50S subunit of prokaryotic ribosomes containing about 3200 nucleotides. 23S rRNA is involved in the initiation of polypeptide synthesis.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Base Composition: The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.RNA, Ribosomal, 5S: Constituent of the 50S subunit of prokaryotic ribosomes containing about 120 nucleotides and 34 proteins. It is also a constituent of the 60S subunit of eukaryotic ribosomes. 5S rRNA is involved in initiation of polypeptide synthesis.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Bacterial Typing Techniques: Procedures for identifying types and strains of bacteria. The most frequently employed typing systems are BACTERIOPHAGE TYPING and SEROTYPING as well as bacteriocin typing and biotyping.RNA, Ribosomal, 28S: Constituent of the 60S subunit of eukaryotic ribosomes. 28S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.Soil Microbiology: The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Bacteria: One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)Ribosomes: Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Seawater: The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Geologic Sediments: A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Ribosomal Proteins: Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.RNA Processing, Post-Transcriptional: Post-transcriptional biological modification of messenger, transfer, or ribosomal RNAs or their precursors. It includes cleavage, methylation, thiolation, isopentenylation, pseudouridine formation, conformational changes, and association with ribosomal protein.Cell Nucleolus: Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.Actinomycetales: An order of gram-positive, primarily aerobic BACTERIA that tend to form branching filaments.Cluster Analysis: A set of statistical methods used to group variables or observations into strongly inter-related subgroups. In epidemiology, it may be used to analyze a closely grouped series of events or cases of disease or other health-related phenomenon with well-defined distribution patterns in relation to time or place or both.Alphaproteobacteria: A class in the phylum PROTEOBACTERIA comprised mostly of two major phenotypes: purple non-sulfur bacteria and aerobic bacteriochlorophyll-containing bacteria.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.RNA, Fungal: Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis.RNA Precursors: RNA transcripts of the DNA that are in some unfinished stage of post-transcriptional processing (RNA PROCESSING, POST-TRANSCRIPTIONAL) required for function. RNA precursors may undergo several steps of RNA SPLICING during which the phosphodiester bonds at exon-intron boundaries are cleaved and the introns are excised. Consequently a new bond is formed between the ends of the exons. Resulting mature RNAs can then be used; for example, mature mRNA (RNA, MESSENGER) is used as a template for protein production.Fresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Polymorphism, Restriction Fragment Length: Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.RNA, Archaeal: Ribonucleic acid in archaea having regulatory and catalytic roles as well as involvement in protein synthesis.Bacteroidetes: A phylum of bacteria comprised of three classes: Bacteroides, Flavobacteria, and Sphingobacteria.RNA Polymerase I: A DNA-dependent RNA polymerase present in bacterial, plant, and animal cells. The enzyme functions in the nucleolar structure and transcribes DNA into RNA. It has different requirements for cations and salts than RNA polymerase II and III and is not inhibited by alpha-amanitin. EC 2.7.7.6.DNA, Archaeal: Deoxyribonucleic acid that makes up the genetic material of archaea.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Ribosome Subunits, Small: The small ribonucleoprotein component of RIBOSOMES. It contains the MESSENGER RNA binding site and two TRANSFER RNA binding sites - one for the incoming AMINO ACYL TRNA (A site) and the other (P site) for the peptidyl tRNA carrying the elongating peptide chain.Biodiversity: The variety of all native living organisms and their various forms and interrelationships.Actinobacteria: Class of BACTERIA with diverse morphological properties. Strains of Actinobacteria show greater than 80% 16S rDNA/rRNA sequence similarity among each other and also the presence of certain signature nucleotides. (Stackebrandt E. et al, Int. J. Syst. Bacteriol. (1997) 47:479-491)Gammaproteobacteria: A group of the proteobacteria comprised of facultatively anaerobic and fermentative gram-negative bacteria.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Korea: Former kingdom, located on Korea Peninsula between Sea of Japan and Yellow Sea on east coast of Asia. In 1948, the kingdom ceased and two independent countries were formed, divided by the 38th parallel.RNA, Transfer: The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.Quinones: Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.RNA, Protozoan: Ribonucleic acid in protozoa having regulatory and catalytic roles as well as involvement in protein synthesis.Methyltransferases: A subclass of enzymes of the transferase class that catalyze the transfer of a methyl group from one compound to another. (Dorland, 28th ed) EC 2.1.1.Vitamin K 2: A group of substances similar to VITAMIN K 1 which contains a ring of 2-methyl-1,4-naphthoquinione and an isoprenoid side chain of varying number of isoprene units. In vitamin K 2, each isoprene unit contains a double bond. They are produced by bacteria including the normal intestinal flora.Betaproteobacteria: A class in the phylum PROTEOBACTERIA comprised of chemoheterotrophs and chemoautotrophs which derive nutrients from decomposition of organic material.Sodium Chloride: A ubiquitous sodium salt that is commonly used to season food.Sewage: Refuse liquid or waste matter carried off by sewers.Proteobacteria: A phylum of bacteria consisting of the purple bacteria and their relatives which form a branch of the eubacterial tree. This group of predominantly gram-negative bacteria is classified based on homology of equivalent nucleotide sequences of 16S ribosomal RNA or by hybridization of ribosomal RNA or DNA with 16S and 23S ribosomal RNA.Ribosome Subunits, Small, Bacterial: The small subunit of eubacterial RIBOSOMES. It is composed of the 16S RIBOSOMAL RNA and about 23 different RIBOSOMAL PROTEINS.Endoribonucleases: A family of enzymes that catalyze the endonucleolytic cleavage of RNA. It includes EC 3.1.26.-, EC 3.1.27.-, EC 3.1.30.-, and EC 3.1.31.-.Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Oligonucleotide Probes: Synthetic or natural oligonucleotides used in hybridization studies in order to identify and study specific nucleic acid fragments, e.g., DNA segments near or within a specific gene locus or gene. The probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the probe include the radioisotope labels 32P and 125I and the chemical label biotin.Deltaproteobacteria: A group of PROTEOBACTERIA represented by morphologically diverse, anaerobic sulfidogens. Some members of this group are considered bacterial predators, having bacteriolytic properties.Aerobiosis: Life or metabolic reactions occurring in an environment containing oxygen.Environmental Microbiology: The study of microorganisms living in a variety of environments (air, soil, water, etc.) and their pathogenic relationship to other organisms including man.Genetic Variation: Genotypic differences observed among individuals in a population.Hot Springs: Habitat of hot water naturally heated by underlying geologic processes. Surface hot springs have been used for BALNEOLOGY. Underwater hot springs are called HYDROTHERMAL VENTS.Pigments, Biological: Any normal or abnormal coloring matter in PLANTS; ANIMALS or micro-organisms.Bacterial Proteins: Proteins found in any species of bacterium.Operon: In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.RNA, Small Nucleolar: Small nuclear RNAs that are involved in the processing of pre-ribosomal RNA in the nucleolus. Box C/D containing snoRNAs (U14, U15, U16, U20, U21 and U24-U63) direct site-specific methylation of various ribose moieties. Box H/ACA containing snoRNAs (E2, E3, U19, U23, and U64-U72) direct the conversion of specific uridines to pseudouridine. Site-specific cleavages resulting in the mature ribosomal RNAs are directed by snoRNAs U3, U8, U14, U22 and the snoRNA components of RNase MRP and RNase P.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Bacillaceae: A family of bacteria which produce endospores. They are mostly saprophytes from soil, but a few are insect or animal parasites or pathogens.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Nocardia: A genus of gram-positive, aerobic bacteria whose species are widely distributed and are abundant in soil. Some strains are pathogenic opportunists for humans and animals.Pol1 Transcription Initiation Complex Proteins: Factors that form a preinitiation complex at promoters that are specifically transcribed by RNA POLYMERASE I.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.DNA Fingerprinting: A technique for identifying individuals of a species that is based on the uniqueness of their DNA sequence. Uniqueness is determined by identifying which combination of allelic variations occur in the individual at a statistically relevant number of different loci. In forensic studies, RESTRICTION FRAGMENT LENGTH POLYMORPHISM of multiple, highly polymorphic VNTR LOCI or MICROSATELLITE REPEAT loci are analyzed. The number of loci used for the profile depends on the ALLELE FREQUENCY in the population.PseudouridineMethane: The simplest saturated hydrocarbon. It is a colorless, flammable gas, slightly soluble in water. It is one of the chief constituents of natural gas and is formed in the decomposition of organic matter. (Grant & Hackh's Chemical Dictionary, 5th ed)Anaerobiosis: The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Nucleic Acid Precursors: Use for nucleic acid precursors in general or for which there is no specific heading.Flavobacteriaceae: A family of bacteria in the order Sphingobacteriales, class Sphingobacteria. They are gram-negative rods, mostly saprophytic in terrestrial and aquatic habitats.RNA: A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Denaturing Gradient Gel Electrophoresis: Electrophoresis in which various denaturant gradients are used to induce nucleic acids to melt at various stages resulting in separation of molecules based on small sequence differences including SNPs. The denaturants used include heat, formamide, and urea.Protein Biosynthesis: The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.Diaminopimelic AcidPlankton: Community of tiny aquatic PLANTS and ANIMALS, and photosynthetic BACTERIA, that are either free-floating or suspended in the water, with little or no power of locomotion. They are divided into PHYTOPLANKTON and ZOOPLANKTON.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Chloroflexi: Phylum of green nonsulfur bacteria including the family Chloroflexaceae, among others.Eukaryota: One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.Rhodobacteraceae: A family in the order Rhodobacterales, class ALPHAPROTEOBACTERIA.Mycoplasma: A genus of gram-negative, mostly facultatively anaerobic bacteria in the family MYCOPLASMATACEAE. The cells are bounded by a PLASMA MEMBRANE and lack a true CELL WALL. Its organisms are pathogens found on the MUCOUS MEMBRANES of humans, ANIMALS, and BIRDS.DNA, Mitochondrial: Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.Transcription Factor TFIIIA: One of several general transcription factors that are specific for RNA POLYMERASE III. It is a zinc finger (ZINC FINGERS) protein and is required for transcription of 5S ribosomal genes.Biodegradation, Environmental: Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.DNA, Protozoan: Deoxyribonucleic acid that makes up the genetic material of protozoa.DNA Probes: Species- or subspecies-specific DNA (including COMPLEMENTARY DNA; conserved genes, whole chromosomes, or whole genomes) used in hybridization studies in order to identify microorganisms, to measure DNA-DNA homologies, to group subspecies, etc. The DNA probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the DNA probe include the radioisotope labels 32P and 125I and the chemical label biotin. The use of DNA probes provides a specific, sensitive, rapid, and inexpensive replacement for cell culture techniques for diagnosing infections.Cytophaga: A genus of gram-negative gliding bacteria found in SOIL; HUMUS; and FRESHWATER and marine habitats.Gentian Violet: A dye that is a mixture of violet rosanilinis with antibacterial, antifungal, and anthelmintic properties.Microbial Consortia: A group of different species of microorganisms that act together as a community.In Situ Hybridization, Fluorescence: A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.Waste Disposal, Fluid: The discarding or destroying of liquid waste products or their transformation into something useful or innocuous.Mycobacterium: A genus of gram-positive, aerobic bacteria. Most species are free-living in soil and water, but the major habitat for some is the diseased tissue of warm-blooded hosts.Halobacteriaceae: A family of extremely halophilic archaea found in environments with high salt concentrations, such as salt lakes, evaporated brines, or salted fish. Halobacteriaceae are either obligate aerobes or facultative anaerobes and are divided into at least twenty-six genera including: HALOARCULA; HALOBACTERIUM; HALOCOCCUS; HALOFERAX; HALORUBRUM; NATRONOBACTERIUM; and NATRONOCOCCUS.Comamonadaceae: A family of gram-negative aerobic bacteria in the class BETA PROTEOBACTERIA, encompassing the acidovorans rRNA complex. Some species are pathogenic for PLANTS.China: A country spanning from central Asia to the Pacific Ocean.Bacteria, AnaerobicSymbiosis: The relationship between two different species of organisms that are interdependent; each gains benefits from the other or a relationship between different species where both of the organisms in question benefit from the presence of the other.Ribosome Subunits, Large, Bacterial: The large subunit of the eubacterial 70s ribosome. It is composed of the 23S RIBOSOMAL RNA, the 5S RIBOSOMAL RNA, and about 37 different RIBOSOMAL PROTEINS.RNA Probes: RNA, usually prepared by transcription from cloned DNA, which complements a specific mRNA or DNA and is generally used for studies of virus genes, distribution of specific RNA in tissues and cells, integration of viral DNA into genomes, transcription, etc. Whereas DNA PROBES are preferred for use at a more macroscopic level for detection of the presence of DNA/RNA from specific species or subspecies, RNA probes are preferred for genetic studies. Conventional labels for the RNA probe include radioisotope labels 32P and 125I and the chemical label biotin. RNA probes may be further divided by category into plus-sense RNA probes, minus-sense RNA probes, and antisense RNA probes.DNA Restriction Enzymes: Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.Aminoglycosides: Glycosylated compounds in which there is an amino substituent on the glycoside. Some of them are clinically important ANTIBIOTICS.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Ribosome Subunits, Small, Eukaryotic: The small subunit of the 80s ribosome of eukaryotes. It is composed of the 18S RIBOSOMAL RNA and 32 different RIBOSOMAL PROTEINS.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Helicobacter: A genus of gram-negative, spiral-shaped bacteria that has been isolated from the intestinal tract of mammals, including humans. It has been associated with PEPTIC ULCER.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Methylation: Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)PhenazinesGenes: A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Flavobacterium: A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in SOIL and WATER. Its organisms are also found in raw meats, MILK and other FOOD, hospital environments, and human clinical specimens. Some species are pathogenic in humans.Ribonucleoproteins, Small Nucleolar: Nucleolar RNA-protein complexes that function in pre-ribosomal RNA processing.Microbiota: The full collection of microbes (bacteria, fungi, virus, etc.) that naturally exist within a particular biological niche such as an organism, soil, a body of water, etc.Cytophagaceae: A family of gram-negative, gliding bacteria in the order Cytophagales, class Cytophagia. They are found in SOIL and SEA WATER.Gram-Positive Endospore-Forming Rods: Rod-shaped bacteria that form endospores and are gram-positive. Representative genera include BACILLUS and CLOSTRIDIUM.Sequence Analysis, RNA: A multistage process that includes cloning, physical mapping, subcloning, sequencing, and information analysis of an RNA SEQUENCE.Ribosome Subunits: The two dissimilar sized ribonucleoprotein complexes that comprise a RIBOSOME - the large ribosomal subunit and the small ribosomal subunit. The eukaryotic 80S ribosome is composed of a 60S large subunit and a 40S small subunit. The bacterial 70S ribosome is composed of a 50S large subunit and a 30S small subunit.Sphingomonadaceae: A family of gram-negative, asporogenous rods or ovoid cells, aerobic or facultative anaerobic chemoorganotrophs. They are commonly isolated from SOIL, activated sludge, or marine environments.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Drug Resistance, Bacterial: The ability of bacteria to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Metagenomics: The genomic analysis of assemblages of organisms.Ribonuclease T1: An enzyme catalyzing the endonucleolytic cleavage of RNA at the 3'-position of a guanylate residue. EC 3.1.27.3.Gram-Positive Endospore-Forming Bacteria: Bacteria that form endospores and are gram-positive. Representative genera include BACILLUS; CLOSTRIDIUM; MICROMONOSPORA; SACCHAROPOLYSPORA; and STREPTOMYCES.Ribosome Inactivating Proteins: N-Glycosidases that remove adenines from RIBOSOMAL RNA, depurinating the conserved alpha-sarcin loop of 28S RIBOSOMAL RNA. They often consist of a toxic A subunit and a binding lectin B subunit. They may be considered as PROTEIN SYNTHESIS INHIBITORS. They are found in many PLANTS and have cytotoxic and antiviral activity.DNA-Directed RNA Polymerases: Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).Haloarcula marismortui: A species of halophilic archaea distinguished by its production of acid from sugar. This species was previously called Halobacterium marismortui.Bioreactors: Tools or devices for generating products using the synthetic or chemical conversion capacity of a biological system. They can be classical fermentors, cell culture perfusion systems, or enzyme bioreactors. For production of proteins or enzymes, recombinant microorganisms such as bacteria, mammalian cells, or insect or plant cells are usually chosen.Ribotyping: RESTRICTION FRAGMENT LENGTH POLYMORPHISM analysis of rRNA genes that is used for differentiating between species or strains.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Soil Pollutants: Substances which pollute the soil. Use for soil pollutants in general or for which there is no specific heading.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Soil: The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.Oligoribonucleotides: A group of ribonucleotides (up to 12) in which the phosphate residues of each ribonucleotide act as bridges in forming diester linkages between the ribose moieties.Bacillus: A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.Prevotella: A genus of gram-negative, anaerobic, nonsporeforming, nonmotile rods. Organisms of this genus had originally been classified as members of the BACTEROIDES genus but overwhelming biochemical and chemical findings in 1990 indicated the need to separate them from other Bacteroides species, and hence, this new genus was established.Ribosome Subunits, Large: The largest ribonucleoprotein component of RIBOSOMES. It contains the domains which catalyze formation of the peptide bond and translocation of the ribosome along the MESSENGER RNA during GENETIC TRANSLATION.Bacteriological Techniques: Techniques used in studying bacteria.Gastrointestinal Tract: Generally refers to the digestive structures stretching from the MOUTH to ANUS, but does not include the accessory glandular organs (LIVER; BILIARY TRACT; PANCREAS).Exoribonucleases: A family of enzymes that catalyze the exonucleolytic cleavage of RNA. It includes EC 3.1.13.-, EC 3.1.14.-, EC 3.1.15.-, and EC 3.1.16.-. EC 3.1.-Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Peptidyl Transferases: Acyltransferases that use AMINO ACYL TRNA as the amino acid donor in formation of a peptide bond. There are ribosomal and non-ribosomal peptidyltransferases.DNA, Intergenic: Any of the DNA in between gene-coding DNA, including untranslated regions, 5' and 3' flanking regions, INTRONS, non-functional pseudogenes, and non-functional repetitive sequences. This DNA may or may not encode regulatory functions.Marine Biology: The study of the origin, structure, development, growth, function, genetics, and reproduction of organisms which inhabit the OCEANS AND SEAS.Ribonucleases: Enzymes that catalyze the hydrolysis of ester bonds within RNA. EC 3.1.-.Ciliophora: A phylum of EUKARYOTES characterized by the presence of cilia at some time during the life cycle. It comprises three classes: KINETOFRAGMINOPHOREA; OLIGOHYMENOPHOREA; and POLYMENOPHOREA.Gram-Positive Cocci: Coccus-shaped bacteria that retain the crystal violet stain when treated by Gram's method.Lactobacillus: A genus of gram-positive, microaerophilic, rod-shaped bacteria occurring widely in nature. Its species are also part of the many normal flora of the mouth, intestinal tract, and vagina of many mammals, including humans. Pathogenicity from this genus is rare.Genes, Archaeal: The functional genetic units of ARCHAEA.Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.Genes, Fungal: The functional hereditary units of FUNGI.Porifera: The phylum of sponges which are sessile, suspension-feeding, multicellular animals that utilize flagellated cells called choanocytes to circulate water. Most are hermaphroditic. They are probably an early evolutionary side branch that gave rise to no other group of animals. Except for about 150 freshwater species, sponges are marine animals. They are a source of ALKALOIDS; STEROLS; and other complex molecules useful in medicine and biological research.Arctic Regions: The Arctic Ocean and the lands in it and adjacent to it. It includes Point Barrow, Alaska, most of the Franklin District in Canada, two thirds of Greenland, Svalbard, Franz Josef Land, Lapland, Novaya Zemlya, and Northern Siberia. (Webster's New Geographical Dictionary, 1988, p66)Base Pairing: Pairing of purine and pyrimidine bases by HYDROGEN BONDING in double-stranded DNA or RNA.Antarctic Regions: The continent lying around the South Pole and the southern waters of the Atlantic, Pacific, and Indian Oceans. It includes the Falkland Islands Dependencies. (From Webster's New Geographical Dictionary, 1988, p55)Chryseobacterium: A genus of aerobic, gram-negative bacteria in the family FLAVOBACTERIACEAE. Many of its species were formerly in the genus FLAVOBACTERIUM.Classification: The systematic arrangement of entities in any field into categories classes based on common characteristics such as properties, morphology, subject matter, etc.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Crenarchaeota: A kingdom in the domain ARCHAEA comprised of thermoacidophilic, sulfur-dependent organisms. The two orders are SULFOLOBALES and THERMOPROTEALES.Saccharomyces cerevisiae Proteins: Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.Fungi: A kingdom of eukaryotic, heterotrophic organisms that live parasitically as saprobes, including MUSHROOMS; YEASTS; smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi, commonly known as molds, refer to those that grow as multicellular colonies.Industrial Waste: Worthless, damaged, defective, superfluous or effluent material from industrial operations.Tetrahymena: A genus of ciliate protozoa commonly used in genetic, cytological, and other research.Gram-Negative Bacteria: Bacteria which lose crystal violet stain but are stained pink when treated by Gram's method.Alteromonadaceae: A family of marine, gram-negative PROTEOBACTERIA including the genera ALTEROMONAS; Colwellia; Idiomarina; MARINOBACTER; MORITELLA; PSEUDOALTEROMONAS; and SHEWANELLA.Genome, Bacterial: The genetic complement of a BACTERIA as represented in its DNA.Mediterranean SeaEscherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.tRNA Methyltransferases: Enzymes that catalyze the S-adenosyl-L-methionine-dependent methylation of ribonucleotide bases within a transfer RNA molecule. EC 2.1.1.Corynebacterium: A genus of asporogenous bacteria that is widely distributed in nature. Its organisms appear as straight to slightly curved rods and are known to be human and animal parasites and pathogens.Ricin: A protein phytotoxin from the seeds of Ricinus communis, the castor oil plant. It agglutinates cells, is proteolytic, and causes lethal inflammation and hemorrhage if taken internally.Heterotrophic Processes: The processes by which organisms utilize organic substances as their nutrient sources. Contrasts with AUTOTROPHIC PROCESSES which make use of simple inorganic substances as the nutrient supply source. Heterotrophs can be either chemoheterotrophs (or chemoorganotrophs) which also require organic substances such as glucose for their primary metabolic energy requirements, or photoheterotrophs (or photoorganotrophs) which derive their primary energy requirements from light. Depending on environmental conditions some organisms can switch between different nutritional modes (AUTOTROPHY; heterotrophy; chemotrophy; or PHOTOTROPHY) to utilize different sources to meet their nutrients and energy requirements.Bacteriochlorophyll A: A specific bacteriochlorophyll that is similar in structure to chlorophyll a.Colony Count, Microbial: Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.Streptococcaceae: A family of gram-positive non-sporing bacteria including many parasitic, pathogenic, and saprophytic forms.Bradyrhizobium: A genus of gram-negative, aerobic, rod-shaped bacteria usually containing granules of poly-beta-hydroxybutyrate. They characteristically invade the root hairs of leguminous plants and act as intracellular symbionts.RNA, Small Nuclear: Short chains of RNA (100-300 nucleotides long) that are abundant in the nucleus and usually complexed with proteins in snRNPs (RIBONUCLEOPROTEINS, SMALL NUCLEAR). Many function in the processing of messenger RNA precursors. Others, the snoRNAs (RNA, SMALL NUCLEOLAR), are involved with the processing of ribosomal RNA precursors.Rhizobiaceae: A family of gram-negative bacteria which are saprophytes, symbionts, or plant pathogens.UridineBlotting, Southern: A method (first developed by E.M. Southern) for detection of DNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Conserved Sequence: A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.Wetlands: Environments or habitats at the interface between truly terrestrial ecosystems and truly aquatic systems making them different from each yet highly dependent on both. Adaptations to low soil oxygen characterize many wetland species.Methylobacterium: A genus of gram-negative, aerobic, facultatively methylotrophic rods occurring singly or occasionally in rosettes. Members of this genus are usually motile and are isolated from soil, dust, fresh water, lake sediments, leaf surfaces, rice, air, and hospital environments. (From Bergey's Manual of Determinative Bacteriology, 9th ed)Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)