Some relations between the morphology and composition of the mycelium ofstreptomyces erythreus and the biosynthesis of erythromycin

Streptomyces erythreus формируется двумя типамимицелия hyphae под во дуусловия в сложной ср еде: Inoculum спор производств а давно, мало разветвле нныхhyphae, из которого выро с густой hyphae на начало рас ти в сфере производства деятельности. Синтетич еской активностимицел ий изменилось одноврем енно сИнтенсивность ро ста микроорганизмаМиц елий был самым продукти вным в течениераннем эт апе autolysis.По мере усиления и нтенсивности и роста производственной деят ельности, содержание са харамицелий компонент ов клеточной стенки decreas изд. В средствах массов ой информации полность ю hydrolyzed разных возрастов к онцентрацииаланин, glutamic кислота и глицин измени лосьаланин, glutamic кислота и глицин изменилосьодн овременно с ростом про изводства иДеятельно сть actinomycete. га-aminobutyric кислота была обнаружена только в мицелий hydrolyzates с начала от резкого снижения тем пов роста интенсивности от микроорганизмов.     

Taxonomical study of the reference strain ofStreptomyces erythreus

The reference strainStreptomyces erythreus formed filamentous growth with Retinaculum-Apertum forms and narrow, long, extended spirals. Under defined conditions it produced abundant red and white mycelium; for its taxonomical characterization the production of red mycelium according to which the strain is classified in a certain series is conclusive. Chains of spiny spores were observed in the electron microscope. In its growth requirements (taxonomically important carbon sources) this strain differed from other strains of the genusStreptomyces. Components of the cell wall type IV were demonstrated in its mycelium.     

Genetic analysis of erythromycin production in Streptomyces erythreus

Streptomyces erythreus produces the 14-membered macrolide antibiotic erythromycin A. The properties of erythromycin A nonproducing mutants and their genetic linkage to chromosomal markers were used to establish the rudiments of genetic organization of antibiotic production. Thirty-three Ery- mutants, produced by mutagenesis of S. erythreus NRRL 2338 and affecting the formation of the macrolactone and deoxysugar intermediates of erythromycin A biosynthesis, were classified into four phenotypically different groups based on their cosynthesis behavior, the type of biosynthetic intermediate accumulated, and their ability to biotransform known biochemical intermediates of erythromycin A. Demonstration of the occurrence of natural genetic recombination during conjugal mating in S. erythreus enabled comparison of the genetic linkage relationships of three different ery mutations with seven other markers on a simple chromosome map. This established a chromosomal location for the ery mutations, which appear to be located in at least two positions within one interval of the map.     

Influence of n-propanol on growth and antibiotic production by an industrial strain of Streptomyces erythreus under different nutritional conditions

Summary The effect of propanol on primary and secondary metabolism of a glucose and phosphorus non-repressive strain of Streptomyces erythreus was studied. Propanol increased erythromycin final titer by 100% as well as biomass (20%), both occuring later in the course of the production phase. A growth-dissociated production metabolism is emphasized by propanol (higher value). A partly growth-associated production pathway tends to switch its production pattern (higher and lower values) with propanol.     

Erythromycin production by Streptomyces erythreus entrapped in calcium alginate beads

Summary Mycelia of Streptomyces erythreus were immobilized in calcium alginate beads and employed for production of erythromycin. Compared to conventional and washed mycelial fermentation, the average specific productivity of immobilised mycelia was superior.     

Degeneration of a homing endonuclease and its target sequence in a wild yeast strain

Mobile introns and inteins self-propagate by ‘homing’, a gene conversion process initiated by site-specific homing endonucleases. The VMA intein, which encodes the PI-SceI endonuclease in Saccharomyces cerevisiae, is present in several different yeast strains. Surprisingly, a wild wine yeast (DH1-1A) contains not only the intein⁺ allele, but also an inteinless allele that has not undergone gene conversion. To elucidate how these two alleles co-exist, we characterized the endonuclease encoded by the DH1-1A intein⁺ allele and the target site in the intein^– allele. Sequence analysis reveals seven mutations in the 31 bp recognition sequence, none of which occurs at positions that are individually critical for activity. However, binding and cleavage of the sequence by PI-SceI is reduced 10-fold compared to the S.cerevisiae target. The PI-SceI analog encoded by the DH1-1A intein⁺ allele contains 11 mutations at residues in the endonuclease and protein splicing domains. None affects protein splicing, but one, a R417Q substitution, accounts for most of the decrease in DNA cleavage and DNA binding activity of the DH1-1A protein. Loss of activity in the DH1-1A endonuclease and target site provides one explanation for co-existence of the intein⁺ and intein^– alleles.     

Evidence for a sex factor in Streptomyces erythreus.

A lethal zygosis-sensitive mutant of Streptomyces erythreus, ER720, was isolated. Pocks were formed when spores of the parental type were plated on a lawn of ER720, suggesting the loss of a transmissible plasmid, SEP1, from this strain. Recombination did not occur between derivatives of ER720 lacking SEP1, but it did occur if SEP1 was transferred to one of these strains or if these strains were crossed with other strains containing SEP1. SEP1 could also be transferred at high frequency between strains. This is consistent with SEP1 acting as a sex factor in S. erythreus.     

cis-benzeneglycol production using a mutant Pseudomonas strain

The biotransformation of commodity aromatic chemicals into dihydroxy derivatives was studied. A strain isolated from the invironment, Pseudomonas JI104, used benzene, toluene, and other hydrocarbons as sole carbon and energy sources. We selected mutants unable to grow with benzene, and among these, screened for strains with deficient cis-benzenglycol dehydrogenase able to stably produce cis-benzeneglycol when another carbon source was co-metabolized.We exained the possibility of cis-benzeneglycol production by growing the mutant strain in the presence of benzene vapor. Ethanol was the carbon and energy source most adapted to the cis-benzeneglycol production phase, and lactate or propanol could also be used. Glucose inhibited the production of the metabolite.The growth rates were barely affected by the presence of benzene at a reduced partial pressure (less than 20% of saturation), showing that continuous culture is possible. In a batch process, 0.54g·1⁻¹ of a cell suspension produced 5.1 mmol·1⁻¹cis-benzeneglycol in 27 h, using ethanol as the energy source.     

Laccase production by a monokaryotic strain of Pycnoporus cinnabarinus derived from a dikaryotic strain

Monokaryotic Pycnoporus cinnabarinus strains were obtained from the dikaryotic strain I-938. One of these, designated MK18, consistently produced high laccase activity. In cultures of MK18 and I-938 where ferulic acid was added as laccase inducer, laccase activity was enhanced about 2.5-fold reaching 3400 U/l for the MK18 strain. Laccase was purified to homogeneity and under the selected growth conditions, only one isoform of the enzyme was produced. The N-terminal sequence was similar to the amino terminal sequence of laccase II from Trametes versicolor. The enzyme was stable at 60 C for more than 1 h.     

Isolation and characterization of Streptomyces erythreus plasmids

Streptomyces erythreus strains were found to carry several plasmids of molecular weights ranging from about 2 X 10(6) Mr to 40 X 10(6) Mr. Restriction enzyme maps for the streptomycete plasmids pPC7 and pPC8 were constructed for the enzymes Bg/II, EcoRI, XbaI, HindIII, BamHI and SalI. The smaller, pPC8, plasmid appears to be a naturally occurring deletion variant of pPC7. These plasmids belong to the group of conjugative streptomycete plasmids.     

Biosurfactant production by a new Pseudomonas putida strain

Observation of both tensio-active and emulsifying activities indicated that biosurfactants were produced by the newly isolated and promising strain Pseudomonas putida 21BN. The biosurfactants were identified as rhamnolipids, the amphiphilic surface-active glycolipids usually secreted by Pseudomonas spp. Their production was observed when the strain was grown on soluble substrates, such as glucose or on poorly soluble substrates, such as hexadecane, reaching values of 1.2 g l(-1). When grown on hexadecane as the sole carbon source the biosurfactant lowered the surface tension of the medium to 29 mN m(-1) and formed stable and compact emulsions with emulsifying activity of 69%.