The role of Ca2+ in hormonal imprinting of the Tetrahymena

It is known from model experiments on Tetrahymena that primary exposure to a hormone induces receptor formation or amplification, in other words a hormonal imprinting. Substances acting on the intracellular Ca2+ level of the Tetrahymena, such as TMB-8, EDTA, EGTA, NiCl2 and La(NO3)3, interfered with hormonal imprinting of the unicellular to different degrees, and some of them influenced hormone (insulin, TSH) binding also independently of imprinting. Interference with the intracellular Ca-metabolism generally influenced imprinting by insulin and TSH, which were mediated by different mechanisms, to dissimilar degrees, or in opposite directions. On combined application of the agents acting on Ca-metabolism, their effects were additive. It appears that intact Ca-mediation is an essential prerequisite for normal hormonal imprinting.     

Degradation dynamics of lignocellulose materials by wood-rottingPleurotus fungi

When grown on wheat straw,Pleurotus decomposes both the lignin and the cellulose components of the substrate. The course of degradation differs during growth and fructification. The losses of dry mass during growth were about 20 %. The absolute amount of hemicelluloses, cellulose and lignin was decreasing. Hemicelluloses and lignin were degraded at a higher rate than cellulose. The total mass losses of the substrate after fructification were 32 to 45 %. Cellulose was consumed at a higher rate than lignin.     

Selective regeneration ofBacillus subtilis protoplasts transformed to kanamycin resistance

An HTY medium osmotically stabilized with 0.5 M D-glucitol was used for regeneration ofBacillus subtilis protoplasts. The application of glucitol as osmotic stabilizer allows simultaneous selection of cells resistant to kanamycin to be made since this antibiotic is not inactivated by glucitol when added to the regeneration medium.     

Alga consumption of four dominant planktonic crustaceans in Lake Balaton (Hungary)

Between 1981–83 the gut contents ofDaphnia galeata, D. cucullata, Eudiaptomus gracilis, andCyclops vicinus were examined with light and scanning electron microscope to obtain information on the feeding of these species in Lake Balaton. The twoDaphnia species feed mainly on abioseston, and it is assumed that their primary nutrient source was organic matter adsorbed onto the surfaces of the abioseston granules plus bacteria and detritus.E. gracilis feeds on algae, showing a preference for green algae and diatoms.C. vicinus is also a prodigious consumer of algae in Lake Balaton, utilizing the whole size spectrum of phytoplankton. Concerning the trophic relationships between phytoplankton and zooplankton in Lake Balaton, that between diatoms and bothE. gracilis andC. vicinus is the most conspicouos. Convincing evidence for an extensive utilization of blue-green algae was not found. Though there is no firm evidence yet, it is likely that theDaphnia are dependent on organic matter adsorbed on the abioseston.     

The effect of feeding high corn oil on fatty-acid-binding-protein isolated from rat liver

Fatty-acid-binding-protein isolated from liver of rats receiving normal or high fat diet was studied by three different methods. The effect of high fat diet on the thermal stability of the protein was determined employing differential scanning calorimetry. Fatty acids have a stabilizing effect on the thermal stability of the protein. In order to determine the relative binding affinity of native and delipidated protein a Sephadex G-50 assay was employed using [1-14C] oleate as ligand. The delipidated protein exhibited greater binding of oleate than did the native material. Increases in the transfer of oleic acid from rat liver microsomes to egg lecithin liposomes in vitro were also observed when protein obtained from both sources were delipidated. The results suggest that high corn oil diet would modify the properties of fatty-acid-binding-protein in the uptake and cytosolic transport of long-chain fatty acids.     

Stability of Lanatoside C content in thein vitro propagatedDigitalis lanata clones

In vitro culture was established from shoot tips ofDigitalis lanata cotyledonous plants. The propagated plant material was rooted, transplanted into soil and grown under field conditions. Lanatoside C content was determined in a total of 20 clones and statistically evaluated by means of variance analysis of unequal-sized samples.In vitro clonal propagation ofD. lanata was found not to affect lanatoside C content. Drug level was dependent on a plant genotype.     

Taxon-dependence of receptor level cell-to-cell communication in Tetrahymena: possible explanation for the transmission of hormonal imprinting

Insulin treatment induced in Tetrahymena pyriformis a positive hormonal imprinting, and in Tetrahymena thermophila a negative imprinting, resulting in increased and decreased binding capacity, respectively, at re-exposure to the hormone. The imprinting, or the information associated with it, is transferred by the nutrient medium of the insulin-treated cells to those not treated. The issue of transfer depends on the nature of the receiver taxon, leading always to a positive imprinting in Tetrahymena pyriformis, and to a negative imprinting in Tetrahymena thermophila, regardless of the nature of the 'imprinted' transmitter taxon. The findings substantiate the transferability of hormonal imprinting by the nutrient medium at the unicellular level, the key role of the postreceptorial mechanism in determining the trend of imprinting and may explain the persistence of imprinting in the progeny generations.     

Leukocyte-derived inhibitory activity in patients with myelodysplastic syndrome

Leukocyte-derived inhibitory activity inhibiting the entry of normal progenitor cells of granulocytes and macrophages (CFU-GM) into the S-phase of a cell cycle was investigated in 16 patients with different forms of myelodysplastic syndrome (MDS). The presence of this inhibitory activity was analysed in medium conditioned with low-density cells obtained from peripheral blood of MDS patients. The inhibition rate was measured by 3H-thymidine suicide technique with subsequent cultivation of pretreated cells in semisolid agar medium. Low-density cells from MDS patients of various types were studied: from the twelve patients with refractory anaemia (RA or RAS) only three were positive, one patient with chronic myelomonocytic leukaemia (CMML) was negative while one patient with refractory anaemia with excess of blasts (RAEB) and two patients with RAEB in transformation (RAEB-T) were positive with respect of the described test. In two patients with RA, who underwent a long-term investigation, the production of leukocyte-derived inhibitory activity preceded the development of disease into RAEB or RAEB-T. In five positive cases, supernatants were incubated with antiserum against human placental ferritin; with one exception, the inhibitory activity was neutralized.     

Analysis of chromosome aberrations and sister-chromatid exchanges in peripheral blood lymphocytes of workers with occupational exposure to the mancozeb-containing fungicide Novozir Mn80

Chromosome aberrations and sister-chromatid exchanges (SCEs) were analyzed in short-term cultures of peripheral lymphocytes of 44 workers occupationally exposed to mancozeb during the production of the pesticide Novozir Mn80 and 30 control persons. The results suggest that mancozeb exposure was associated with a significant increase in the frequencies of cells with structural chromosome aberrations (2.07% vs. 1.10% in the controls), and the number of SCEs per cell (9.19 +/- 1.81 vs. 7.82 +/- 1.04 in the controls).     

Effect of bromocriptine and progesterone on the length of the ovarian cycle in 4- and 5-day estrous cyclic rats

To study the effect of prolactin and progesterone on the length of the reproductive cycle in the rat, rats of different estrous cycle length (four and five days, respectively) were injected daily (09.00 h) with either bromocriptine (1 mg/rat) or 70% ethanol vehicle (0.25 ml) from the day of estrus onward, up to the appearance of the next ovulation. Each group of rats was then (16.00, metestrus) also injected with either progesterone (4 mg/rat) or 0.2 ml of olive oil. The effects of these treatments on the length of the estrous cycle was studied by both the recording of vaginal smears daily and by direct visualization of oocyte-cumulus complexes on the ensuing day of estrus (10.00 h-12.00 h). Bromocriptine treatment shortened the length of the cycle by one day in 5-day but not in 4-day cyclic rats, while progesterone treatment lengthened estrous cycles by one day in both groups of rats. Treatment with both bromocriptine and progesterone had no effect on the estrous cycle length of 5-day cyclic rats, but did prolong in one day the cycle of 4-day cyclic rats. These facts suggest that prolactin regulates the length of the ovarian reproductive cycle in the rat through its action on the secretion of progesterone by the corpus luteum.