New species, Actinomadura fulvescens sp. nov. and Actinomadura turkmeniaca sp. nov. and their antagonistic properties

Two new species of Actinomadura isolated from soil samples of the Turkmen SSR, i.e. Actinomadura fulvescens sp. nov. and Actinomadura turkmeniaca sp. nov. are described. The first species is characterized by formation of short (1-2 turns) spiral spore chains, smooth spores, scanty white aerial mycelium, colourless or yellowish substrate mycelium on synthetic media and brownish-yellow substrate mycelium and soluble pigment of the same colour on organic media. No melanoid pigment is secreted. The type culture is designated as INA 3321. The cultures of A. fulvescens show antibiotic activity. A. turkmeniaca is characterized by formation of short straight or spiral spore chains, smooth spores, scanty white aerial mycelium, substrate mycelium and soluble pigment of pinkish-violet colour, absence of melanoid pigment. The type culture is designated as INA 3344. The strains of this species have low antibiotic activity. The study on the use of carbon sources by the representatives of 7 species (9 strains) of Actinomadura showed that the majority of the cultures (5 species, 7 strains) produced no growth on the Pridham and Gottlieb medium (ISP-9) with various carbon sources, including glucose. Possibly this medium cannot be used as the main medium for investigation of the spectrum of carbohydrate consumption in Actinomadura.     

Effect of various carbon and nitrogen sources on the biosynthesis of ristomycin, protease and pigments by a culture of Nocardia fructiferi var. ristomycini

The effect of various sources of carbon and nitrogen on the biosynthesis of ristomycin, protease and pigments by Nocardia fructiferi was studied. It was shown that the carbon sources had the most significant effect on the biosynthesis of the antibiotic. The maximum biosynthetic activity of the Nocardia was observed in the medium containing 1-2 per cent of soybean meal and 2 per cent of glycerol. Under such conditions all the three biologically active substances formed. The contents of ristomycin, protease and pigments amounted to 562-649 microgram/ml, 26-30 PU/ml and 0.45-0.63 conditional units, respectively.     

Kinetic aspects of the relation of the growth of the producer and the biosynthesis of heliomycin depending on the carbon source in the medium

Kinetic parameters of Streptomyces olivocinereus 11-98 growth and biosynthesis of heliomycin were studied. It was shown that carbon sources such as glycerol, mannitol and ramnose were the most favourable for the antibiotic biosynthesis. These carbon sources belonged to the group of substances providing high growth rates of the culture. Ranging of the culture growth rates and antibiotic production levels revealed a set of carbon sources providing a converse relationship between the growth rate and antibiotic biosynthesis i.e. L-arabinose, potassium gluconate, raffinose and sucrose. It was suggested that these compounds were catabolic type regulators of heliomycin biosynthesis.     

Fibrinolytic activity of Bacillus mesentericus strains

Two Bacillus mesentericus strains with a high activity of proteolytic enzymes having the thrombolytic action were selected from a group of its collection strains. The effect of different carbon sources on the synthesis of proteases was studied. A growth medium containing potato broth (10%), peptone (0.5%) and lactose (0.5%) allowed one to obtain a cultural broth dissolving human blood clots within 2.5 to 3 hours in experiments in vitro.     

Studies on a new marine streptomycete BT-408 producing polyketide antibiotic SBR-22 effective against methicillin resistant Staphylococcus aureus

A new actinomycete strain designated as BT-408 producing polyketide antibiotic SBR-22 and showing antibacterial activity against methicillin resistant Staphylococcus aureus has been characterized and found to be a novel strain of Streptomyces psammoticus. Nutritional and cultural conditions for the production of antibiotic by this organism under shake-flask conditions have been optimized. Glucose and ammonium nitrate were found to be best carbon and nitrogen sources respectively for growth and antibiotic production. Similarly initial medium pH of 7.2, incubation temperature of 30 degrees C and incubation time of 96 h were found to be optimal. Optimization of medium and cultural conditions resulted in 1.82-fold increase in antibiotic yield.     

Influence of the culture medium on the production of iturin A by Bacillus subtilis

The production of iturin A by Bacillus subtilis was studied with respect to the composition of the culture medium. Increasing phosphate concentrations did not modify the antibiotic yield. Fructose, sucrose and mannitol were better carbon sources than glucose for antibiotic production. The nature of the nitrogen source was an important factor in the production of antibiotic. Among the amino acids which are components of iturin A, L-asparagine was the best substrate for the biosynthesis of iturin A; L-glutamine and L-serine were rather poor substrates while L-proline and D-tyrosine gave no antibiotic. Ammonium salts permitted good synthesis of antibiotic but the addition of calcium ions to the culture medium inhibited the excretion of antibiotic from the cells.     

Influence of various nitrogen and carbon sources on the production of pectolytic,cellulolytic and proteolytic enzymes byAspergillus niger

Three isolates ofAspergillus niger produced polygalacturonase (PG) and pectin methyl galacturonase (PMG) in the presence of organic and inorganic nitrogen sources. Complete inhibition of PG PMG cellulase (C_x) and proteinase synthesis was found in the presence of cystine in all isolates. Maximum biomass was found in sodium nitrate whereas no isolate could grow in the presence of cystine. A correlation between biomass and enzyme production could be obtained when sodium nitrate and cystine were added to the medium separately. All isolates produced pectic cellulolytic and proteolytic enzymes in the presence of various native carbon sources. Sodium polypectate was found to be the best carbon source for the production of PG and PMG; pectin inhibited completely the production of PG and PMG. Maximum cellulase production was brought about by cotton in all three isolates. Maximum proteinase production was observed with gelatin which served as poor substrate for fungal growth. Sucrose supported maximum fungal growth in comparison with all other native carbon sources. The increased production of pectolytic cellulolytic and proteolytic enzymes in the presence of sodium polypectate reflected a stimulation rather than an induction of synthesis of these enzymes.     

Role of the carbon source in regulating chloramphenicol production by Streptomyces venezuelae: studies in batch and continuous cultures

Both carbon- and nitrogen-limited media that supported a biphasic pattern of growth and chloramphenicol biosynthesis were devised for batch cultures of Streptomyces venezuelae. Where onset of the idiophase was associated with nitrogen depletion, a sharp peak of arylamine synthetase activity coincided with the onset of antibiotic production. The specific activity of the enzyme was highest when the carbon source in the medium was also near depletion at the trophophase-idiophase boundary. In media providing a substantial excess of carbon source through the idiophase, the peak specific activity was reduced by 75%, although the timing of enzyme synthesis was unaltered. Moreover, chemostat cultures in which the growth rate was limited by the glucose concentration in the input medium failed to show a decrease in specific production of chloramphenicol as the steady-state intracellular glucose concentration was increased. The results suggest that a form of "carbon catabolite repression" regulates synthesis of chloramphenicol biosynthetic enzymes during a trophophase-idiophase transition induced by nitrogen starvation. However, this regulatory mechanism does not establish the timing of antibiotic biosynthesis and does not function during nitrogen-sufficient growth in the presence of excess glucose.     

Ligninolytic enzyme production by Phanerochaete chrysosporium under conditions of nitrogen sufficiency

Abstract A lignin-degrading enzyme has been detected in culture supernatants of Phanerochaete chrysosporium strain INA-12 grown under non-limiting nitrogen conditions. Highest levels of enzyme activity were observed when glycerol served as carbon source. Veratryl alcohol, a known secondary metabolite of P. chrysosporium , was also produced in high nitrogen/glycerol cultures of strain INA-12 and closely followed the development of the 'ligninase' activity. Evolution of ¹⁴CO₂ from ¹⁴C-ring-DHP was readily observed when a hydrogen peroxide-generating system was added to 5-day-old high nitrogen/glycerol cultures which contained high amounts of enzyme.     

Production of an antifungal antibiotic by Streptomyces aburaviensis 1DA-28

A broad-spectrum antifungal Streptomyces isolate, 1DA-28, from Indian soil has been characterized and identified as Streptomyces aburaviensis var. ablastmyceticus (MTCC 2469). Nutritional and cultural conditions for the production of antibiotic by this organism under shake-flask conditions have been determined. Antibiotic production in synthetic medium reached the maximum on the 5th day of incubation at 30 degreesC. Glucose and starch were found to be the best carbon sources while NH4NO3 was preferred as nitrogen source. Optimum temperature and pH for antibiotic production were 32 degreesC and 7.4, respectively. Phosphate at a concentration sub-optimal for growth enhanced antibiotic production. Supplementation of medium with casein hydrolysate improved both growth and antibiotic titre but yeast extract exhibited marked inhibition.     

Nutritional requirements ofLysobacter lactamgenus for the production of cephabacins

Summary To optimize the fermentation medium for the production of new cephem compounds, cephabacins, by an eubacteriaLysobacter lactamgenus IFO 14,288, the effects of medium components on cephabacin production were investigated. Supplementation of glucose as a sole carbon source in liquid media was the best for the antibiotic production as well as for the cell growth. Casamino acid was the best nitrogen source for antibiotic biosynthesis and cell growth among nitrogen sources tested, and this strain could utilize sulfate or thiosulfate as a sulfur source. No significant effects of growth factors (vitamins) on the antibiotic production and cell growth were observed, but ferrous, magnesium and nickel ions slightly enhanced the cephabacin production.     

Cytogenetic study for possible mutagenic activity induced by ice-nucleation bacteria or their metabolic products in human lymphocytes in vitro

A means for eliminating ice-nucleation-active (INA) bacteria, the microorganisms responsible for frost damage to plants at mild freezing temperatures, is the use as competitors of other naturally occurring, non-nucleating strains. Inactive mutants (INA-) of INA bacteria have been produced by genetic or chemical methods and proposed for biological control of INA populations. Since, however, the application of these INA- mutants in the field may create health hazards to animals, we have studied the possible mutagenic activity of the INA- mutants by examining chromosome aberrations, sister-chromatid exchange (SCE) frequencies, and proliferation kinetics of human lymphocyte cultures. These cultures were treated with: (a) a naturally occurring INA- bacterium (p 767), (b) 2 parental strains (cit 7 and cit 13) of INA bacteria isolated from Citrus orchards, and (c) 2 INA- mutant strains (cit 7 del 1b and cit 13-12), produced, respectively, by chemical modification and by deletion of the corresponding parental strains. Neither whole bacteria nor infiltrates of bacterial growth media, in which toxic metabolic bacterial products might have been released, induced elevation of either chromosome aberrations and SCEs or a cell-division delay. Negative results were also obtained when sonicated bacteria were tested for possible intracellular mutagenic components.     

Some characteristics of fucidin biosynthesis]

Some features of fusidin biosynthesis by 2 strains of Fusidium coccineum were studied proceeding from the peculiar properties of the antibiotic molecule structure. It was found that an increase in the levels of the carbon sources in the medium stimulated the biosynthesis of fusidin, while excessive concentrations of nitrogen especially in its inorganic and amino acidpeptide forms stimulated the organism growth and lowered the antibiotic activity levels. The concentration of nitrogen in the medium is considered as one of the possible control mechanisms in the processes of the fungus growth and biosynthesis of fusidin.     

Application of factorial design to the optimization of medium composition in batch cultures of Streptomyces lividans TK21 producing a hybrid antibiotic

Summary The composition of the liquid medium employed to obtain a hybrid antibiotic in batch cultures of a recombinant strain of Streptomyces lividans TK21 has been studied. Starch and glutamic acid are the most appropriate carbon and nitrogen sources to support respectively cell growth and antibiotic production. A central composite experimental design has been employed to derive a statistical model of the effect of phosphate and glutamic acid on growth and antibiotic production, and an initial concentration of 10 mM phosphate and 52.8 mM glutamic acid have been found optimal to maximize the final antibiotic concentration in batch cultures.     

The effects of temperature on growth and production of the antibiotic granaticin by a thermotolerant streptomycete

The synthesis of granaticin, a polyketide-derived antibiotic synthesized as a secondary metabolite by Streptomyces thermoviolaceus strain NCIB 10076, was studied at different growth temperatures. Quantitative measurements of the antibiotic made during batch fermentations showed that the yield was greatest at 45 degrees C, whereas the rate of synthesis was most rapid at 37 degrees C. The timing of the appearance of granaticin in culture could not be assigned to any particular phase of growth or to de-repression due to depletion of any particular nutrient. However, at all temperatures, appearance of the antibiotic coincided with a rise in ammoniacal nitrogen presumably due to deamination of glutamate, the carbon source for growth. We have previously shown that production of the antibiotic is pH sensitive and that some carbon sources result in higher titres than others. This paper examines the effect of temperature on the physiology of growth and on antibiotic production in more detail under conditions that also allow an exact measurement of granaticin yield.     

牛筋草离孺孢生物学特性及代谢产物活性测定

对牛筋草离孺孢属(Bipolaris sorokiniana)NJ-08菌株的生物学特性及代谢产物除草活性测定结果表明：此菌株的菌丝体生长速度慢, 但产孢量大, 致病性强。菌丝体生长最适温度25°C, 致死温度是55°C/10 min, 最适pH值为8, 碳源以葡萄糖最佳, 供试氮源则不利于菌丝体生长。产生分生孢子最适温度25°C, 最适pH值为8, 碳源以葡萄糖最好, 氮源以硝酸钠产孢量最高。分生孢子萌发温度在20°C~35°C之间没有差异, 适宜pH值为5~7, 碳源以D-木糖的孢子萌发率最高, 氮源以蛋白胨的孢子萌发率最高, 不同处理间存在明显差异。NJ-08菌株产生的代谢产物作用于牛筋草, 可使叶片黄化或枯死, 代谢产物对指示植物及杂草如柱花草、地桃花、猪屎豆和辣椒的胚根胚芽生长都有明显的抑制作用, 抑制率均超过了90%, 显示出很好的除草活性。     

Factors affecting antimicrobial activity of Synechococcus leopoliensis

An antimicrobial agent is produced by the cyanobacterium Synechococcus leopoliensis which was found to be active against the Gram-positive bacterium Staphylococcus aureus. The effects of temperature, pH, incubation period, some media and different nitrogen and carbon sources on both growth and antimicrobial activity were investigated. Temperature 35 °C and pH 8 were the best for growth and antimicrobial agent production and 14 and 15 days of incubation were found to be the best for maximum growth and antimicrobial activity, respectively, in the medium BG-11.

No antimicrobial activity could be detected by the use of G medium, moderate activity was recorded with Chu 10 medium, while high activity was reported in BG-11 medium. Leucine was the best nitrogen source for antimicrobial activity, while maximum antimicrobial activity was introduced by using the carbon sources, citrate and acetate. Very high antimicrobial activity could be detected by using the carbon source galactose in combination with the nitrogen source alanine or by using arabinose with methionine.     

Regulation of phosphoglycerate dehydrogenase levels and effect on serine synthesis in Escherichia coli K-12.

The level of phosphoglycerate dehydrogenase, the first enzyme in the biosynthetic pathway to serine and glycine, has been studied in Escherichia coli grown under different conditions. The enzyme level was not reduced by growth in a medium which contained the end products of the pathway, nor was it elevated when the growth rates was limited by the supply of serine. Elevation of phosphoglycerate dehydrogenase did not occur when charging of tRNA ser was inhibited by serine hydroxamate. However, phosphoglycerate dehydrogenase levels were subject to regulation. Elevated levels of enzyme activity were observed in merodiploids containing multiple copies of the serA gene, and lowered enzyme levels were found in cells grown on carbon sources other than glucose or when certain amino acids were present in the growth medium. The combined effect of these nutritional changes (carbon source and amino acids) reduced the level of phosphoglycerate dehydrogenase to 10 to 12% of that found in wild-type cells and to about 5% of the level in the merodiploids. By using antibody prepared against purified phosphoglycerate dehydrogenase we established that the decrease in enzyme activity reflected decreased amounts of enzyme protein. Constant intracellular concentrations of 3-phosphoglycerate and serine were found in cells with marked differences in phosphoglycerate dehydrogenase activity, indicating that end product inhibition of phosphoglycerate dehydrogenase activity, rather than the amount of the biosynthetic enzymes, is the major factor in regulating the intracellular concentration of serine.     

Optimal protease production condition for Prevotella ruminicola 23 and characterization of its extracellular crude protease

In this study, Prevotella ruminicola 23 (ATCC 19189), a ruminal proteolytic bacterium, was used as protease producer to examine the optimal condition for protease production. The best carbon and nitrogen sources for the maximum growth were glucose with peptone. Both sucrose and glucose could stimulate high protease production. Casein and peptone are better nitrogen sources for protease production than other choice in this study. The best enzyme production condition was 18-20 h incubation which was at late log phase in the broth of 5% glucose or sucrose as carbon source with 0.1% ammonium chloride and 0.2% peptone as nitrogen sources. Most of the protease activity was secreted into broth (65%) and on cell surface (18%). The optimal temperature and pH for protease reaction were 40 degrees C and pH 6.8, respectively. After incubation for 6h, the crude extract maintained 50% of original protease activity at 30 and 50 degrees C, and protease activity was stable between pH 6 and 8. The protease inhibitor test showed that serine, aspartic acid and metallo-protease inhibitors could cause inhibition of proteolysis. Protein feedstuff degradation experiments suggested that protease in crude extract had higher degradation ability on fish meal, whey, and feather meal (2.39, 2.60 and 1.76 micromol aminoacid/mg enzyme/h) in comparison to soybean meal and blood meal (1.11 and 1.09 micromol aminoacid/mg enzyme/h). The protease in the crude extract should have application potential in term of improving utilization of fish meal and feather meal for monogastric animals.