Trichomonas vaginalis: expression and characterisation of recombinant S-adenosylhomocysteinase.

The gene encoding S-adenosylhomocysteinase activity (S-adenosylhomocysteine hydrolase, SAHH; EC 3.3.1.1) in Trichomonas vaginalis has been expressed in Escherichia coli to facilitate the characterisation of the enzyme. Expression of this gene using the pQE-30 (6xHis N-terminal tag) expression system (QIAGEN) has enabled the one-step purification of 6 mg of active recombinant enzyme from a 100-ml bacterial culture by affinity chromatography using a nickel-NTA matrix. The recombinant enzyme has a molecular weight of approximately 56,000 and identification of tryptic peptides by matrix-assisted laser desorption ionisation (MALDI) mass spectrometry has shown that the purified recombinant protein is identical in primary structure to the predicted sequence. The presence of the N-terminal 6xHis tag in the recombinant enzyme did not appear to affect its kinetic and other properties, which are similar to those exhibited by the "native" enzyme present in cell-free extracts of T. vaginalis. These properties include a similar apparent Km for adenosine (20-25 microM for the recombinant and 5-10 microM for the native enzymes, respectively) and similar inhibition/inactivation patterns exhibited by adenosine analogues such as arabinosyl adenine (ara-A).

Molecular characterisation of adenosylhomocysteinase from Trichomonas vaginalis.

The enzyme S-adenosylhomocysteine hydrolase (SAHH) has been identified as a potential target for chemotherapy in protozoan parasites including Trichomonas vaginalis. To investigate this area of trichomonad metabolism in more detail, we have isolated and characterised a gene which encodes this activity from the WAA38 strain of this parasite. The gene was isolated by probing a Bg/II genomic mini-library with a fragment of the gene generated by thermal cycling using degenerate oligonucleotide primers. A 5.9-kb Bg/II clone was isolated and has been partially sequenced to reveal a 1458-bp open reading frame which encodes a 486-residue polypeptide (computed molecular mass of 53.4 kDa). The deduced amino acid sequence showed a high degree of sequence similarity to the hydrolases from other species, but was most similar to the enzyme from photosynthetic organisms. The trichomonal sahh gene also contains two "insertion sequences', one of which appears to be unique to this parasite while the second has previously been found only in photosynthetic organisms and in Plasmodium falciparum. Characterisation of the sahh mRNA from T. vaginalis confirmed that both of these insertion sequences (encoding 9 and 37 amino acid residues, respectively) are expressed in the protein product. The sahh mRNA is similar to those characterised from other protozoa in having a short, 12-bp untranslated 5'-leader sequence but the leader sequence does not conform well with the consensus sequence of the other mRNAs. Finally, Southern blots and sequence differences between genomic and cDNA clones indicate that there are multiple copies of the sahh gene in T. vaginalis.

[The immunological status of Cyprinus carpio L. in experimental mycotoxicosis]. / Immunologicheskii status Cyprinus carpio L. pri éksperimental'nom mikotoksikoze.

Some humoral factors of nonspecific resistance have been determined in carp yearlings in 28 days after intraperitoneal administration of fungi culture filtrate (I), conidia (II), micellar extract (III) of the fungus Aspergillus fumigatus Fres., physiological solution (control). The toxicogenic and immunogenic effect of the fungus has been shown in I and II variants of the experiment respectively. The injection of fungus micella did not have any influence on the studied factors. The account of specific and quantitative composition of zooparasites in experiments and under control has been carried out; no truly differences have been revealed.

[X-ray semeiotics of functional changes of the respiratory organs in patients with tuberculosis of the lungs and the obstructive syndrome]. / Rentgenosemiotika funktsional'nykh izmenenii organov dykhaniia u bol'nykh tuberkulezom legkikh s obstruktivnym sindromom.

Examination included 178 patients with active pulmonary tuberculosis and moderate obstruction (74 subjects) or severe obstructive syndrome (104 subjects). The dynamic morphofunctional X-ray examination along with a study of external respiratory function made it possible to study the pattern of functional disturbances in patients with tuberculosis of respiratory organs and concurrent bronchial obstruction. Roentgeno-pneumopolygraphy supplemented with physical exercise tests and berotec specified the localization, extent and the character of disorders of bronchial patency and enabled one to study the compensatory mechanisms of external respiratory function during antibacterial therapy. According to the data of roentgeno-pneumopolygraphy, the more serious air-filling disorders are, the more pronounced the bronchial obstructive changes are, while the degree of respiratory disorders depends on the type and extent of the process and on the duration of the disease and its genesis.

[Roentgenological symptoms of functional changes in the respiratory organs of patients with pulmonary tuberculosis]. / Rentgenosemiotika funktsional'nykh izmenenii organov dykhaniia u bol'nykh tuberkulezom legkikh.

To study typical disorders in the external respiration function of patients with pulmonary tuberculosis without concurrent bronchial obstruction and to find out an information potential of the roentgeno-pneumo-polygraphic+ (RPPG) method in detecting local obstructive disturbances, 53 subjects aged from 23 to 52 years with respiratory tuberculosis, including 38 and 15 of them with a limited or disseminated process, respectively, were examined. X-ray functional examination conducted in dynamics and with the use of physical load and bronchodilators made in possible to discover both local and disseminated occult bronchial obstruction. Application of RPPG method and administration of such bronchodilator, as berotec, revealed a functional nature of the bronchial obstruction. According to RPPG data. In a lingering tuberculous process a costal component is predominant in the course of respiration.

[X-ray semiotics of the morphological and functional changes in chronic bronchitis]. / Rentgenosemiotika morfologicheskikh i funktsional'nykh izmenenii pri khronicheskikh bronkhitakh.

The authors analysed structural disorders of a pulmonary pattern in patients with non-obstructive, obstructive and purulent bronchitis. Characteristic x-ray symptom-complexes were singled out for each clinical variant of the disease. In addition to roentgenomorphological changes functional disorders showing changes of biomechanics in patients with chronic bronchitis were revealed at roentgenopneumopolygraphy.