Thiosulfate production from cystine by the keratinolytic prokaryote Streptomyces fradiae

In cultures of Streptomyces fradiae on wool as the only source of nutrition inorganic thiosulfate (in amounts up to 0.5 mg of Na₂S₂O₃·5 H₂O/ml) was formed as the final product of metabolization of sulfur from cystine of keratin proteins. The presence of thiosulfate was proved by qualitative tests and thin-layer chromatography and estimated quantitatively by spectrophotometry, titrimetry, and capillary isotachophoresis. Metabolization of organic sulfur to thiosulfate excreted into the medium is a process not yet described in microorganisms.     

Comparative histology of antelope placentomes

The histological structure of ruminant (family: Bovidae) placentomes in eight antelope species was compared to that of domestic cattle and sheep. The chorioallantoic villi differed in degree of branching, surface corrugation, and complexity of utero-placental junction. All species had the epitheliochorial type of placenta, with the epithelial lining of maternal caruncular crypts varying between cellular and syncytial types.     

A comparison of the drying of chymotrypsin bound to bead cellulose by lyophilisation and in air at 25 to 70°C

Summary The effect was studied of the method of drying chymotrypsin attached to bead cellulose on its chemical and physical characteristics. These characteristics are not deteriorated when replacing the commonly used lyophilisation by fluid drying in the air stream. The preparations saved essentially the same proteolytic activity as well as stability even when increasing the drying air temperature to 70°C.     

Transfer factor of131I from the fallout to human thyroid dose equivalent after the Chernobyl accident

Summary A similar pattern of variation with time in observed maxima of daily dose equivalent rates in human thyroids (TD - µSv·d^–1) and of daily fallout radioactivities (FR - kBq·m^–2) has been found after the Chernobyl accident. An estimate of the time-lag between the maxima in TD lines and the preceding FR peaks was made of about seven days for adult and nine days for juveniles. Applying this time-lag it was possible to estimate transfer factors from the fall-out to thyroid dose equivalent: the highest estimated values were 221 µSv/kBq·m^–2 for adult and 641 µSv/kBq·m^–2 for juvenile thyroids. These values differ from those published by UNSCEAR (United Nations 1988), which have been calculated for various regions of Czechoslovakia, from ingestion and inhalation intake estimates. A broad variation of transfer factor values could be expected to result from such transfer calculations using ingestion and inhalation estimates. The findings also support the concept of a need for prolonged iodine prophylaxy after emissions of radioiodine into the environment.Abbreviations TD dose equivalent rates in thyroids [µSv·d^–1] - FR fall-out radioactivity (-ies) [kBq·m^–2]     

Plasma endothelin 1/2 levels in healthy blood donors as measured by RIA--a clinical application.

Normal endothelin 1/2 levels and their correlation with age were evaluated. For clinical application of the endothelin 1/2 RIA test, optimum storage conditions were investigated. Plasma endothelin 1/2 (ET) levels were measured in 36 healthy blood donors, mostly males, of mean age 36 +/- 8 years, subdivided into three age groups: 17-30, 31-40 and above 40 years old. The mean normal ET levels in the three age groups, and corresponding standard deviations, were: 0.58 +/- 0.19, 0.62 +/- 0.31, and 0.80 +/- 0.28 fmol/ml, respectively. The mean ET level for the whole normal population was 0.66 +/- 0.28 fmol/ml. Only differences between mean ET levels for the first and last groups were statistically significant (p < 0.05). Differences between mean ET levels in smokers (53% of total population) and non-smokers, women and men, irrespective of age, were found not to be statistically significant. At this stage of our work, we conclude that other factors than age alone play a role in enhancing ET levels above the age of 41 years. In our study of optimum storage conditions for endothelin 1/2, we found that after one week of storage at -24 degrees C the mean level of ET measured in frozen plasma dropped to 85% of the initial activity, while after the same period the respective decrease in ET activity in frozen extracts was 49%. Over the next two weeks, ET levels in plasma and extracts dropped to 57% and 32% of "zero time" activities, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Microflora participating in the decomposition of carboxymethyl cellulose continuously added to the soil

The microbial community in the soil was analyzed during four weeks of a continuous enrichment of structural chernozem soil samples with a 0.1% solution of carboxymethyl cellulose (CMC) under aerobic and semianaerobic conditions. During the first 14 d, the total amount of the aerobic and anaerobic, cellulose-degrading microorganisms increased significantly. Various metabolic pathways were u‘ed te decompose the substrate: diverse metabolic systems were activated and different groups of microorganisms preferred in dependence on the presence of oxygen or the source of mineral nitrogen. In the later phases of cultivation, a decrease in the concentration of zymogenous microflora and in the level of substrate mineralization was observed ovon though CM-cellulase activity remained high. During the fourth week of cultivation, a conspicuous increase in the numbers of oligothropic bacteria occurring in the colcnies of the microorganisms degrading cellulose was found. The representatives of prosthecobacteria (Caulobacter, Hyphomicrobium, Prosthecomicrobium spp.) andSeliberia sp. were thus identified. This “microflora of dispersion” attends the zymogenous microbes degrading CMC and indicates later phases of the process of decomposition.     

Adherence to epithelial cells and ultrastructure of fosfomycin-resistant mutants of group A streptococci

Adherence of three strains of group A streptococci and their fosfomycin-resistant mutants to HEp-2 tissue culture cells was compared with some cell-surface characteristics, i.e. ultrastructure and hydrophobicity. Among Fosr mutants, both well-adhering and weakly adhering mutants were found. Clonal analysis of the mutants proved their greater stability in the adherence. Well-adhering parent strains of streptococci and Fosr mutants exhibited surface fibrillae in contrast to weakly adhering Fosr mutants which were devoid of fibrillae or contined fibrillae of lower electron density. Decrease of adherence of Fosr mutants of two strains was accompanied by a decrease of their hydrophobicity.     

Leaf water potential and leaf conductance during the growing season in almond trees under different irrigation regimes

Seasonal changes in leaf water potential (Φ) and leaf conductance (g₁) were determined in almond trees under different irrigation regimes. The development of water stress in the rainfed treatment induced a specific seasonal dynamics of Φ values and an important reduction in g₁ values. A decrease in g₁ values occurred independently of the irrigation treatment through the growing season. No statistically significant differences were obtained in g₁ values within the drip irrigated treatments.     

Chromosome condensation activity in the cytoplasm of anucleate and nucleate fragments of mouse oocytes

The activity of maturation promoting factor (MPF) which causes chromosome condensation and subsequent oocyte maturation was investigated in mouse oocytes using polyethylene-glycol-mediated cell fusion technique. Fully grown oocytes were bisected at germinal vesicle (GV) stage or shortly after germinal vesicle breakdown (GVBD) into anucleate and nucleate fragments. After 2-3 or 15-17 hr of culture these fragments were fused with interphase blastomeres from two-cell embryos. It was found that almost all the anucleate oocyte fragments cultured for a short term (2-3 hr), regardless of whether they were produced at GV stage or after GVBD, induced premature chromosome condensation in the blastomere nuclei, whereas only about 20% of those cultured for a long term (15-17 hr) could do so. On the other hand, the nucleate fragments always retain the cytoplasmic activity to induce chromosome condensation. Thus we suggested that the MPF initially could appear in mouse oocytes independently of the GV, that the mixing of GV material with the oocyte cytoplasm following GVBD had no effect on the activity of MPF in anucleate fragments, and that oocyte chromosomes or some components associated with them could play a significant role in maintaining the MPF activity.