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Biomedical subjects

J Stastná

Publications and source records attributed to J Stastná.

At least 19 recordsLinked to original sources
PubMed1992

Characteristics of Streptomyces globisporus strain 0234A forming endospores in submerged cultures.

Thermosensitive submerged endospores formed by Streptomyces globisporus 0234 and its natural variant A resembled those of thermoresistant actinomycetes not only in their morphology ultrastructure, but also in the content of dipicolinic acid. The production of endospores containing this substance is unusual in Streptomyces while other features of the strain indicate relatedness to other streptomycetes. Chemotaxonomic analysis of variant A revealed the cell wall to be of chemotype I and fatty acid content typical of Streptomyces. Most characteristics of surface cultures of variant A coincided with those of the original strain 0234 and its endosporeless variant B. Both the strain 0234 and its variants A and B produced identical antibiotics and pesticidal compounds.

Anti-Bacterial Agents↗
PubMed1991

Characterization of an asporogenous mutant of Streptomyces aureofaciens with increased resistance to several aminoglycoside antibiotics.

An asporogenous spontaneous mutant of Streptomyces aureofaciens named ASR1 was selected on streptomycin gradient plates. The mutant is very stable and differs in ultrastructure and morphology, it is prototrophic but it lost the ability to grow well on soybean extract medium and produces one-tenth tetracyclines of the parent. The ASR1 mutant has a 3-4-fold increased resistance to streptomycin and is cross-resistant to other aminoglycosides. Comparison of the protein profiles from both strains on SDS gels revealed a very low expression of a 29.5 kDa protein in the ASR1 mutant which is overexpressed in both vegetative cells and spores of the parental strain.

Aminoglycosides↗
PubMed1989

Submicroscopic localization of glycogen in mouse blastocysts developed in vivo and in blastocysts developed in vitro from two-cell embryos.

Ultrahistochemical method according to Thiéry (1967) was used to determine the occurrence and localization of glycogen in blastocysts developed in vivo and in blastocysts developed from 2-cell embryos of the mouse for 62 to 64 h in in vitro culture. The presence of glycogen was found in blastocysts of both experimental groups. Glycogen had a monoparticulate character, i.e. the form of beta-granules, localized above all in the ground cytoplasm of cells. Their size varied from 10 to 30 nm. In the blastocysts developed in the physiological uterine environment the glycogen content was relatively low, trophoblasts cells containing regularly a higher amount of glycogen particles than embryoblast cells. In the blastocysts developed in the culture medium in the presence of currently used energy sources the distribution and content of glycogen were clearly graded according to the cell types. Compared with the in vivo-blastocysts, an abnormally high amount of glycogen was observed in the cytoplasm of trophoblast cells, a medium amount in the prospective endoderm cells and the minimum amount in the prospective ectoderm cells. The authors are of the opinion that differences in the accumulation of glycogen and its occurrence in the individual cells are in connection with their position in the blastocyst and with their relation to the surrounding microenvironment. It can be judged from the findings of glycogen deposits inside autophagic vacuoles and multivesicular bodies as well as inside extracellular located sacs that simultaneously with glycogen accumulation there also proceeds its partial degradation in lysosomal structures of blastocyst cells.

Animals↗
PubMed1988

Mycobacterial species responsible for tuberculosis and mycobacteriosis cases in the Czech Socialist Republic, 1981-1985.

This study is based on the analysis of nation-wide notification data on the bacteriologically proved mycobacterial infections registered in the national Information System on Bacillary Tuberculosis. Over the 5-year period under study, as many as 2,226 M. tuberculosis isolations were on average reported annually in the country (i.e. 21.6 per 100,000 population), and of these 62.5% were isolations in males, 63.5% were repeated isolations and 87% were isolations from sputum specimens; identification of human of M. bovis infection was reported in 13 patients annually only, mostly in those of higher age categories. The annual average of notified M. kansasii isolations was 138 (1.3 per 100,000 population), repeated isolations of the agent were reported in 66.6% of patients, mostly males 45-54 years old, and 81% of all reports came from an endemic area in the North-Moravian Region; notification of positive M. avium-intracellulare isolations occurred in 24 persons annually, in 48% of these repeatedly, M. xenopi isolation was reported in 87 and M. fortuitum/chelonei in 12 cases annually.

Adolescent↗
PubMed1987

An antibiotic-overproducing mutant of Streptomyces granaticolor with impaired differentiation.

A thy- tetracycline-resistant mutant of Streptomyces granaticolor was prepared by mutagenesis of the parental strain ETH 7437. The mutant exhibits a different morphology and an overproduction of granaticins. The ability to form an aerial mycelium and spores has been lost. The mutant cells have a round or an atypical shape and a thick cell wall, the membraneous system is enlarged by numerous mesosomes. Division septa are formed rarely. The mutant is more sensitive to both low and high temperature than the parental strain. The altered features are stably maintained for many generations. Ribosomal proteins of the mutant do not differ substantially from those of the original strain indicating that the mutant phenotype is not due to an alteration at the translational level.

Antibiotics, Antineoplastic↗
PubMed1987

Identification of an inducible penicillinase of the lithoautotrophic hydrogen-oxidizing bacterium Alcaligenes eutrophus.

The growth of Alcaligenes eutrophus in the presence of benzylpenicillin under heterotrophic and autotrophic conditions was studied. The drug induced a penicillinase in the cells, which can be readily released and extracted from the cells after a lysozyme and EDTA treatment in the course of spheroplast formation. The isoelectric point of the enzyme is 8.1 and the molar mass was estimated to be nearly 25 kg/mol. Phenoxypenicillin is hydrolyzed in the presence of the enzyme at a higher relative rate than benzylpenicillin, ampicillin, amoxycillin and azlocillin. The cephalosporins tested, i.e. cephalosporin C, cefalexin, cefotaxime and 7-aminocephalosporanic acid, were hydrolyzed at a substantially lower relative rate than the penicillins, indicating that the enzyme is a penicillinase.

Alcaligenes↗
PubMed1987

Skin reactivity to mycobacterial antigens in children living in an area of Mycobacterium xenopi endemicity.

Intradermal skin tests with a 2TU dose of PPD-RT 23 prepared from M. tuberculosis and 0.1 ug/0.1 ml of PPD-RS 631 from M. xenopi were simultaneously carried out in 378 7-year-old children from two localities in North-Bohemian region's capital Ustí n. Lab., a focus of M. xenopi endemicity repeatedly confirmed since its disclosure in 1980 by positive M. xenopi isolations from humans and public water supply network. A further group 157 children serving as controls was from Prague district 4 where no presence of M. xenopi strains was ever recorded. All of these children had received routine immunization at birth with Czech BCG vaccine. The children from the two endemic localities were found to give a positive 6 mm or greater reaction to M. xenopi mycobacterin in 43.3% and 22.3%, to human tuberculin in 12.8% and 12.6%, respectively. The frequency histogram clearly separated a group of reactors with 8-18 mm indurations from a group of nonreactors showing a skin induration of 4-8 mm. The higher reactivity of this exposed child population was also reflected in a larger proportion of reactions greater to M. xenopi PPD than to human tuberculin antigen: the reactions greater by 1-5 mm accounted, respectively, for 25.1% and 20.6%, reactions greater by 6 mm or more for 23.7% and 15.9%. Among a group of children from Prague district 4, 6.4% had medium-sized and 3.8% large-sized reactions to M. xenopi antigen; the proportion of reactions greater to M. xenopi antigen than to human tuberculin accounted for only 5.1%, reactions greater to tuberculin than to sensitin were here in slight predominance. The evidenced skin sensitization to M. xenopi mycobacterin is suggested to result from the different degrees of exposure to infection by environmental mycobacteria.

Antigens, Bacterial↗
PubMed1984

RNA and ribosomal protein patterns during aerial spore germination in Streptomyces granaticolor.

Disruption of the external sheath of Streptomyces granaticolor aerial spores and subsequent cultivation in a rich medium result in a synchronous germination. This method was used to analyze RNA and protein patterns during the germination. The germination process took place through a sequence of time-ordered events. RNA and protein synthesis started during the first 5 min and net DNA synthesis at 60-70 min of germination. Within the first 10 min of germination, synthesis of RNA was not sensitive to the inhibitory effect of rifamycin. During this period rRNA and other species including 4-5-S RNA were synthesized. Dormant spores contained populations of ribosomes or ribosomal precursors that were structurally and functionally defective. The ribosomal particles bound a sporulation pigment(s) of the melanine type. The ribosomal proteins complexed to the pigments formed insoluble aggregates which were easily removed from the ribosomes by one wash with 1 M NH4Cl. During the first 10 min of germination, pigment(s) were liberated from the complexes with the ribosomes and protein extracts of the washed ribosomes had essentially the same pattern as the extracts of ribosomes of vegetative cells. These structural alterations were accompanied by enhancement of the ribosome activities in polypeptide synthesis in vivo and in vitro. When the spores were incubated with a 14C-labelled amino acid mixture in the presence of rifamycin, only three proteins (GS1, GL1 and GS9) were identified to be radiolabelled in the extracts from the washed ribosomes. These experiments indicate that liberation of the sporulation pigment(s) from the complexes with ribosomal proteins and assembly of de novo synthesized proteins and proteins from a preexisting pool in the spore are involved in the reactivation of the ribosomes of dormant spores of S. granaticolor.

DNA Replication↗
PubMed1984

Comparative testing of skin reactions to PPD mycobacterins from Mycobacterium tuberculosis and Mycobacterium scrofulaceum in school-age children.

Comparative skin tests with 2 TU PPD-RT 23 with Tween 80 (prepared from M. tuberculosis) and 5 TU PPD-RS 95 with Tween 80 (prepared from M. scrofulaceum) were intradermally given to a total of 1,140 7-year-old children in two towns of Karviná district (340 and 255 children) and in Teplice (267 children) and Prague (278 children). In the two groups of Karviná district children the percentages of small-sized reactions (6-9 mm) to PPD-RT 23 were 13.6 and 22.3% compared to 7.1% in Teplice and 5.7% in Prague. The prevalence of small reactions to the PPD-RS 95 test in district of Karviná was 14.4 and 16.9%, in Teplice 4.5% and in Prague 6.8%. In the two towns of Karviná district the percentages of children whose reaction to PPD-RS 95 was larger than to PPD-RT 23 were 56.4 and 42.8%, in Teplice 24% and in Prague 24%. The hypothesis is advanced that the higher degree of skin hypersensitivity to the M. scrofulaceum mycobacterin which was found among the Karviná district children tested is due to sensitization with environmental mycobacteria which are common in this area.

Child↗
PubMed1983

Toxicity of morphazinamide compared with pyrazinamide.

In a toxicological study on rats two derivatives of pyrazine: morphazinamide (MZA) and pyrazinamide (PZA) were compared with the objective to verify the possibility of using MZA as a substitute for the hepatotoxic PZA. The daily recorded weight and food intake of the rats were statistically significantly changed in the experimental groups with MZA as well as those with PZA, as compared with the control group and the group fed parallelly, already after the sixth dose of MZA and PZA 2.5 g per kg body weight, and similarly changed were also the various biochemical blood and liver tissue tests. Yet, certain differences were observed between the action of MZA and PZA. Some explanation was obtained from PZA blood and tissue concentrations, determined in the course of 24 hours following the administration of the sixth dose of both drugs. A repeated administration of MZA led to a PZA cumulation in the blood and organs of the rats. The study demonstrated that both drugs are hepatotoxic and, in high doses, also nephrotoxic. Moreover, MZA decreases the concentration of plasmatic iron and causes spleen atrophy. It will not be, therefore, a suitable substitute for the hepatotoxic PZA.

Animals↗
PubMed1983

Pharmacokinetics of antituberculosis drugs after oral isolated and simultaneous administration in triple combination.

On the basis of a mathematical analysis of the time course of the drug distributed in the organism there were studied pharmacokinetics of antituberculosis drugs after an isolated oral administration of doses used in daily treatment of tuberculosis, in INH, RMP, EMB, PZA, ETA, CS and TZ, and after a simultaneous--single and repeated--administration of INH, RMP, EMB in a triple combination, after the usual daily doses and after increased intermittent doses administered twice weekly. At first there were determined, with the use of chemical methods, blood concentrations of the antituberculosis drugs studied and their excretion with urine in an unchanged form. The results were analyzed pharmacokinetically by means of a one- compartment model with absorption. By an iteration process, based on non-linear regression analysis, the following pharmacokinetic parameters were calculated: Vd, Ka, Ke, T0.5 abs, T0.5 el, Tmax, Cmax, Clp tot and AUC. Their comparison revealed the following facts: The microbiologically most effective antituberculosis drugs--INH and RMP--are comparable even from the point of view of pharmacokinetics on account of similar pharmacokinetic parameters; in comparison with them EMB has half the size of the AUC, characterizing the efficacy of the drug. In this parameter PTA exceeds more than twice ETA; CS and TZ have a low Ke as well as Clp tot and a high T0.5 el, which is indicative of an insufficient excretion of both drugs. Pharmacokinetic parameters of PZA confirm the possibility of using the dose of 25 mg/kg in the treatment of tuberculosis. A simultaneous administration of the triple drug combination under study influences pharmacokinetic parameters of all the three antituberculosis drugs--it significantly decreases Ka as well as Ke, increases T0.5 el, Tmax, Vd and in INH also Clp tot, but only after a repeated administration. An intermittent administration of the mentioned triple drug combination significantly increases the area under the curve AUC in all the three antituberculosis drugs. This explains the same efficacy of higher doses of antituberculosis drugs, administered twice weekly, in comparison with a daily administration of lower doses of the same combination. The pharmacokinetic process of orally administered antituberculosis drugs can be analyzed according to a one-compartment model of pharmacokinetics, although the kinetics of certain antituberculosis drugs probably proceed in the organism in a more complicated way.

Administration, Oral↗
PubMed1983

Electron microscopic and cytochemical study of the cortical cytoplasm in the preovulatory human oocytes.

Important changes take place in the cortical cytoplasm of human oocytes in connection with their maturation. Contacts between granulosa cell processes and the oocyte are interrupted, the perivitelline space develops, invaded by oocyte long microvilli. Fine flocculent material is deposited in the perivitelline space. As for oocyte cell organelles, changes occur especially in the granular endoplasmic reticulum which, formerly creating a network of cisternae studded with a low number of ribosomes, eventually becomes disintegrated, splitting into individual smooth vesicles scattered together with mitochondria throughout the cytoplasm. The number of Golgi structures drops substantially. Cortical granules mature and become organized into a single layer beneath the cell membrane. Acid mucopolysaccharides, glycoproteins and proteins were demonstrated in their contents. In addition to the above cortical granules, morphologically distinct secretory vesicles are present in the cortical cytoplasm of human preovulatory oocytes. Their number increases markedly during the resumption of meiosis when they release their contents into the perivitelline space. Like the extracellular flocculent material deposited in the perivitelline space, also the secretory vesicles contain glycoproteins and proteins. The extrusion of this glycoprotein material into the perivitelline space coincides temporally with the loosening of microvilli, previously embedded in the zona pellucida material, and with the interruption of oocyte-follicular cells contacts.

Adult↗
PubMed1982

Isolation and characterization of Streptomyces aureofaciens protein-synthesis elongation factor Tu in an aggregated state.

The ability of EF-Tu to aggregate spontaneously was employed for the purification of homogeneous EF-Tu . GDP from Streptomyces aureofaciens. The formation of filamentous structures in the aggregated EF-Tu was demonstrated in a light microscope. The purified factor, with a specific activity of 19,100 +/- 1,000 units/mg in [3H]GDP exchange, was shown to be active in the translation of poly(U). Aggregated EF-Tu . GDP exhibited almost eight-times lower GDP-exchange capacity at 2 degrees C than at 30 degrees C. This suggests that GDP-binding sites are not freely accessible at lower temperatures in the aggregated factor, in contrast to Escherichia coli polymerized EF-Tu. Turbidimetric assays revealed that the solubilization of diluted aggregated S. aureofaciens EF-Tu is strongly dependent on temperature and causes an increase in the number of accessible GDP-binding sites.

Bacterial Proteins↗