Natural compounds containing alternating carbonyl and methylene groups (beta-polyketones), bioenergenetically derived from repeated condensation of acetyl coenzyme A via malonyl coenzyme A, in a process similar to fatty acid synthesis.

Large enzyme complexes composed of a number of component enzymes that are found in STREPTOMYCES which biosynthesize MACROLIDES and other polyketides.

A group of often glycosylated macrocyclic compounds formed by chain extension of multiple PROPIONATES cyclized into a large (typically 12, 14, or 16)-membered lactone. Macrolides belong to the POLYKETIDES class of natural products, and many members exhibit ANTIBIOTIC properties.

A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.

Sets of enzymatic reactions occurring in organisms and that form biochemicals by making new covalent bonds.

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)

A genus of gram-positive bacteria whose spores are round to oval and covered by a sheath.

Compounds based on ANTHRACENES which contain two KETONES in any position. Substitutions can be in any position except on the ketone groups.

A genus of ascomycetous fungi of the family Hypocreaceae, order Hypocreales including several pathogens of grains and cereals. It is also the source of plant growth regulators such as gibberellin and gibberellic acid.

Keto-pyrans.

Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.

A genus of ascomycetous fungi of the family Chaetomiaceae, order SORDARIALES. Many members are cellulolytic and some mycotoxic. They occur naturally on paper and cotton fabric.

A TETRACYCLINE analog isolated from the actinomycete STREPTOMYCES rimosus and used in a wide variety of clinical conditions.

A plant genus of the family PIPERACEAE. Members contain prenylated quinones.

(S-(E))-3,4,5,6,8,10-Hexahydro-14,16-dihydroxy-3-methyl-1H-2-benzoxacyclotetradecin-1,7(8H)-dione. One of a group of compounds known under the general designation of resorcylic acid lactones. Cis, trans, dextro and levo forms have been isolated from the fungus Gibberella zeae (formerly Fusarium graminearum). They have estrogenic activity, cause toxicity in livestock as feed contaminant, and have been used as anabolic or estrogen substitutes.

A genus of SPONGES in the family Plakinidae, with the skeleton formed by small diactine (and some triactine) needle-like terminations.

The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.

Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)

A phylum of small sessile aquatic animals living as small tufted colonies. Some appear like hydroids or corals, but their internal structure is more advanced. Most bryozoans are matlike, forming thin encrustations on rocks, shells, or kelp. (Storer & Stebbins, General Zoology, 6th ed, p443)

The enzymatic synthesis of PEPTIDES without an RNA template by processes that do not use the ribosomal apparatus (RIBOSOMES).

Cyclic esters of hydroxy carboxylic acids, containing a 1-oxacycloalkan-2-one structure. Large cyclic lactones of over a dozen atoms are MACROLIDES.

Complex pharmaceutical substances, preparations, or matter derived from organisms usually obtained by biological methods or assay.

A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)

Polyacenes with four ortho-fused benzene rings in a straight linear arrangement. This group is best known for the subclass called TETRACYCLINES.

Directed modification of the gene complement of a living organism by such techniques as altering the DNA, substituting genetic material by means of a virus, transplanting whole nuclei, transplanting cell hybrids, etc.

The study of the origin, structure, development, growth, function, genetics, and reproduction of organisms which inhabit the OCEANS AND SEAS.

A soil-dwelling actinomycete with a complex lifecycle involving mycelial growth and spore formation. It is involved in the production of a number of medically important ANTIBIOTICS.

A coenzyme A derivative which plays a key role in the fatty acid synthesis in the cytoplasmic and microsomal systems.

S-Acyl coenzyme A. Fatty acid coenzyme A derivatives that are involved in the biosynthesis and oxidation of fatty acids as well as in ceramide formation.

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.

An order of rod-shaped, gram-negative fruiting gliding bacteria found in SOIL; WATER; and HUMUS.

Consists of a polypeptide chain and 4'-phosphopantetheine linked to a serine residue by a phosphodiester bond. Acyl groups are bound as thiol esters to the pantothenyl group. Acyl carrier protein is involved in every step of fatty acid synthesis by the cytoplasmic system.

Hydrocarbons with more than one double bond. They are a reduced form of POLYYNES.

A class of enzymes that transfers substituted phosphate groups. EC 2.7.8.

Ligases that catalyze the joining of adjacent AMINO ACIDS by the formation of carbon-nitrogen bonds between their carboxylic acid groups and amine groups.

The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)

Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.

A bacteriostatic antibiotic macrolide produced by Streptomyces erythreus. Erythromycin A is considered its major active component. In sensitive organisms, it inhibits protein synthesis by binding to 50S ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins.

The functional hereditary units of BACTERIA.

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.

Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).

A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.

Proteins found in any species of bacterium.

Procedures by which protein structure and function are changed or created in vitro by altering existing or synthesizing new structural genes that direct the synthesis of proteins with sought-after properties. Such procedures may include the design of MOLECULAR MODELS of proteins using COMPUTER GRAPHICS or other molecular modeling techniques; site-specific mutagenesis (MUTAGENESIS, SITE-SPECIFIC) of existing genes; and DIRECTED MOLECULAR EVOLUTION techniques to create new genes.

The relationships of groups of organisms as reflected by their genetic makeup.

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.

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.