N-Alkane uptake and utilisation by Streptomyces strains.

Streptomyces strains isolated from the Kuwait Burgan oil field were defined as S. griseoflavus, S. parvus, and S. plicatus utilised n-hexadecane, n-octadecane (purified fractions of mineral oil), kerosene, and crude oil as sole carbon and energy sources. The strains were incubated with n-alkanes and increase of the fatty acid content with chain length equivalent to the employed n-alkanes was observed. Signal transducing GTP-binding proteins (GBPs) play an important role in n-alkane uptake in streptomycetes. Specific activators of GBPs increased the uptake of hydrocarbons. Using the hydrophobic fluorescent dye diphenylhexatrien (DPH) as a probe, it was found that the microviscosity of the hydrophobic inner region of the cellular membrane is significantly lower in hydrocarbon utilisers than in non-utilisers. This difference probably reflects differences in the fatty acid composition of the strains. When cultures were grown in n-alkane containing media, electron microscopy revealed that the hydrocarbon utilisers showed less-electron dense areas as inclusions in the cytoplasm. Soil samples inoculated with Streptomyces strains eliminated hydrocarbons much faster than those not containing these strains, serving as control. When inorganic medium was supplied with n-hexadecane-1-14C as sole carbon and energy source, radioactive CO2 was detected. Since streptomycetes have not been used until now for oil elimination, though they are known as abundant soil bacteria tolerating extreme conditions, their possible use for bioremediation of hydrocarbon contaminated soils is discussed.

Hydrocarbon uptake by Streptomyces.

Oligocarbophilic Streptomyces strains capable of hydrocarbon uptake and utilization were isolated from the polluted desert of Kuwait and used in this study. Transmission electron-microscopy of hyphae revealed that they become enriched with large less electron dense areas in the cytoplasm, when biomass samples were incubated with alkanes. The Streptomyces isolate could utilize n-hexadecane as sole carbon and energy source and their fatty acid content showed an increase in the fatty acids with chain length equivalent to those of the alkane substrates. Fluorescence measurements of diphenylhexatriene dissolved in the representative alkane, n-hexadecane, showed that the kinetics of hydrocarbon uptake are quite different in hydrocarbon-utilizer compared with non-utilizer Streptomyces strain. Microviscosity of the cellular membrane of the utilizer strain was also different from that of the non-utilizer control strain Streptomyces griseus after incubation in the presence of n-hexadecane. Very likely the hydrocarbon utilizer transported these compounds more efficiently across their membranes and accumulated them as inclusions in the cytoplasm.

The faecal actinomycete flora of Protracheoniscus amoenus (woodlice; Isopoda).

Following a marked order of preference, adults of Protracheoniscus amoenus consumed in preference tests the fallen, weathered leave species of forest litter much more selectively than those of the millipede Chromatoiulus projectus. Under natural circumstances, the individuals (prejuveniles, juveniles, young adults and adults) of these two species live frequently together in the forest litter-layer, feeding on weathered leaves of the very same tree species and placing their faecal pellets in the vicinity of each other. Accordingly, there is a high probability of mutual contamination with their faecal bacteria. In contrast, promicromonospora-type intestinal actinomycetes characterized by cell-wall composition type VI colonize only the faeces of Ch. projectus, and are completely lacking of the dropped pellets of woodlice. Diverse species of streptomycetes were detected in the fresh faecal matter of both litter-dwelling animal species, but presumably they were only survivors of gut passage and passive travellers through the digestive canal.

Studies on the selection of streptomycetes in the rhizoplane of sugar-cane.

The overwhelming majority of species of Streptomyces (S. aburaviensis, S. chromofuscus, S. collinus, S. tenebrarius, S. galilaeus, etc.) and Streptoverticillium aureoversales indigenous in the cultivated horizon of the red ferralitic tropical soil of an investigated sugar-cane plantation, were completely lacking in the root surface region of this plant. Only two species (S. griseorubiginosus and S. viridochromogenes) characterized by very broad C- and N-source utilization spectra, proved capable of colonizing the roots of sugar-cane under natural circumstances. They are not stable members of the rhizoplane but, in contrast to many other species of Streptomyces, are very successful occasional root colonizers. S. viridochromogenes occurred also in the root far soil region but S. griseorubiginosus could only be detected in the rhizoplane.

Is the colour of the mature aerial mycelium (spore mass) of streptomycetes a diagnostic key-character of decisive taxonomic importance?

A white sporulated stable mutant strain (strain No. 66/m) of a Streptomyces sp. belonging to the nigrescens group of the typical grey Streptomyces spp. has been isolated. On the basis of ISP *International Streptomyces Project) criteria strain No. 66/m would be considered a true member of the albus-group of Streptomyces (regarded by some workers as a well separated assemblage of species) all the more so because it fits into this alien group at least in such a degree as into that from which it has originated. Caution is necessary in using the aerial mycelium colour as a distinguishing diagnostic property for establishing large intraspecific groups, series, or even in separating species of Streptomyces.

Effect of antenatal glucocorticoid administered in a single dose on the incidence of respiratory distress syndrome in premature infants.

Authors administered glucocorticoid in the cases of 116 pregnant women admitted with premature delivery beginning between 28--36 weeks of gestation to prevent respiratory distress syndrome (RDS). Prednisolone-sodium succinate (Di-Adreson F. Organon) was given intramuscularly in a single dose of 100 mg. 314 infants born before introduction of the corticosteroid prevention on the 28--36 weeks of gestation whose mothers had not been given corticosteroid served as a control group. The frequency of RDS on the treated group was 8,62% while 101 of 314 infants on the control group showed RDS (32,16%). Number of infants of hyaline membrane disease was 3 and 40, respectively. A close correlation could be observed between the interval lasting from therapy to delivery and RDS incidence. In infants born within 24 hours after administration of Di-Adreson F. aquosum injection RDS developed in 58,33% while in those born within 24--48 hours RDS was diagnosed only on 3 cases (8,57%). No RDS was found in babies born after 2 days following the therapy. There were no significant differences between treated and control groups in Apgar scores and the mean weights of infants. These findings seem to suggest that 100 mg of prednisolonesodium succinate administered in a single dose significantly reduces the incidence of RDS in premature infants.

Composition and properties of the actinomycete flora in a ferralitic tropical soil (oxisol)-sugar cane ecological system.

Streptomycetes constituted about 46--48 per cent of the total aerobic microflora in the cultivated horizon of the studied ferralitic tropical soil below sugar cane plantation. This streptomycete fraction of the soil microbial community was composed of 13 (or more) species of Streptomyces (S. chromofuscus, S. chromogenus, S. diastatochromogenes, S. flavochromogenes, S. griseolus, S. nigrescens, S. phaeofaciens, S. sterilis, S. violaceus, Streptomyces sp. I--III), and Streptoverticillium (Sv. aspergilloides). None of these organisms did occur, with detectable frequency of occurrence, in the root surface region of sugar cane. Here, in the rhizoplane, we found a numerically small population of streptomycetes (about 5 per cent of the total bacterial flora), composed of two species (Streptomyces sp. IV and S. griseorubiginosus) which were, however, not detected in soil samples.

Isolation of Streptomyces finlayi from the rhizoplane of Egyptian clover (Trifolium alexandrinum).

A representative strain (531) of green streptomycetes occurring in the root surface region of Egyptian clover (Trifolium alexandrinum) was identified as a typical strain of Streptomyces finlayi, a species which seems capable of living, in loose protocooperative or commensalistic association, also with soil invertebrates (Szabó 1974). In the aerial mycelium of strain 531, spore-chains both with a typical hairy sheath and without a sheath (smooth spores) were observed. According to our present and previous observations the release of spores after the disruption of the hairy sheath seems to be a frequently occurring phenomenon in the aerial mycelium of many strains of S. finlayi.

Amniotic fluid shake test versus lecithin-sphingomyelin ratio in the antenatal prediction of respiratory distress syndrome.

Surfactant content of 211 amniotic fluid samples raken between 28 and 42 weeks' gestations was determined by the shake test. Parallel with this also the lecithin/sphingomyelin (L/S) ratio was measured in 99 cases. When the test was positive no respiratory distress syndrome (RDS) occurred, while 25 RDS (53.34%) developed in 46 newborns with negative test and 8 RDS (15.38%) in 52 newborns with intermediate test. RDS was observed in all cases when the L/S ratio was below 1.5. At L/S ratios between 1.5 and 2.0, RDS appeared in 50% of the negative tests and 20% of the intermediate tests. However, when the L/S ratio was over 2.0 no RDS occured even in the case of negative tests. For the clinical praxis the positive test gives an exact information; no RDS is to be expected in such cases. In the case of a negative test, however, the authors think is necessary also to determine the L/S ratio.

Changes in the surface layer (sheath) of the cell wall of streptomycetes during sporulation.

Fine structural changes of the sheath, occurring during spore formation in strains Streptomyces finlayi ATCC 23 340 and Streptomyces coeruleorubidus FBUA 328 were investigated by means of electron microscopy of air-dried whole mounts and thin sections. The results suggest that in the strains the process of sporulation is not strictly synchronized spatially with the molecular arrangements and re-arrangements (formation of hairy or spiny surface ornaments) occurring outside the wall of the sporulation hyphae, in the sheath. On the contrary, the intensity of transformation induction in the sheath may show a gradually decreasing tendency from the tip of the sporulating hypha towards its sterile basal part, resulting in the formation of both ornamented and smooth spores in the same chain. This suggests that the morphogenetic changes occurring in the sheath during spore formation are probably controlled by a "functional centre", located near the tip of the sporulating hypha, and this centre is perhaps indentical with the cell unit at the tip.

Taxonomy of primycin producing actinomycetes. I. Description of the type strain of thermomonospora galeriensis.

Strain FBUA 1274 (=strain 28/650707, Hungarian National Collection of Medical Bacteria, National Institute of Public Health, Budapest) is designated the type strain of Thermonospora galeriensis (Vályi-Nagy et al.) comb. nov., and the morphological characteristics of this strain are described.