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J Lukes

Publications and source records attributed to J Lukes.

At least 37 records · Page 2Linked to original sources
PubMed2000

Suramin blocks nucleotide triphosphate binding to ribosomal protein L3 from Trypanoplasma borreli.

Ribosomal protein L3 (L3) has been demonstrated to participate in formation of the peptidyltransferase center and is essential for its catalytic activity. In the present study we show that L3 is able to bind nucleotide triphosphates with high and specific affinity in vitro. L3 was serendipitously identified by screening of a genomic phage library from a primitive kinetoplastid flagellate Trypanoplasma borreli with the ATPase domain of the topoisomerase II gene as a probe. The cloned gene was overexpressed and purified as a his-tag fusion protein in E. coli. Radioligand binding experiments, using [gamma-35S]ATP, showed that L3 is able to bind ATP but also GTP and UTP with similar high affinity (IC50 50-100 nM), while it has no ATPase activity. Furthermore, we showed that L3 has more than 500-fold higher affinity for nucleotide triphosphates compared to the corresponding nucleotide monophosphates and diphosphates. Molecular genetic and biochemical analyses allowed us to localize the NTP binding domain of L3 to the N-terminal 296 residues. Suramin, a polysulfonated naphthylamine derivative of urea, known for its chemotherapeutic effects completely inhibited the binding of [gamma-35S]ATP at subclinical levels. Results obtained with surface plasmon resonance technology showed that suramin both forms weak multimolecular complexes with L3 and binds strongly to L3 in nearly stoichiometric amounts.

Adenosine Triphosphatases↗
PubMed2000

Phylogeny of the bodonid flagellates (Kinetoplastida) based on small-subunit rRNA gene sequences.

The phylogeny of kinetoplastid flagellates was investigated by determining the sequences of the small-subunit (18S) rRNA from Bodo designis, Bodo saltans K, Bodo saltans P, Bodo sorokini, Bodo sp. (cf. uncinatus), Cruzella marina, Cryptobia helicis, Dimastigella mimosa and Parabodo nitrophilus and analysing these data together with several previously obtained sequences. The root of the kinetoplastid tree was tentatively determined to be attached to the branch of B. designis and/or Cruzella marina. Within this topology, the suborder Trypanosomatina appears as a late-emerging monophyletic group, while the suborder Bodonina is paraphyletic. Within the bodonid subtree, the branches of parasitic organisms were intermingled with free-living ones, implying multiple transitions to parasitism. The tree indicates that the genera Cryptobia and Bodo are artificial taxa. In addition, the separation of the fish cryptobias and Trypanoplasma borreli as different genera was not supported.

Animals↗
PubMed2000

Phylogenetic analysis of Trypanosomatina (Protozoa: Kinetoplastida) based on minicircle conserved regions.

Phylogenetic relationships within the suborder Trypanosomatina were inferred from the kinetoplast DNA minicircle conserved region sequences. Trees built using distance-matrix (Neighbor-Joining) and maximum parsimony methods showed that the minicircle conserved regions (CRs) provide a sensitive and specific molecular marker suitable for phylogenetic analyses of subspecies and strains of trypanosomatid flagellates, as testified by the subdivision of the genus Leishmania into the subgenera Leishmania. Viannia and Sauroleishmania. However, since Phytomonas and monogenetic parasites of insects represent the earliest diverging groups, the CRs do not seem to be useful for inference of relationships among major lineages of the order Kinetoplastida.

Animals↗
PubMed1999

Phylogenetic analysis of Sarcocystis spp. of mammals and reptiles supports the coevolution of Sarcocystis spp. with their final hosts.

Sequences of the small subunit rRNA genes were obtained for two coccidians, Sarcocystis dispersa and an unnamed Sarcocystis sp. which parasitise the European barn owl and an African viperid snake as their final host, respectively, and share mouse as their intermediate host. Phylogenetic analysis of the sequence data showed that Sarcocystis sp. from the viperid snake is most closely related to another Sarcocystis sp. isolated from an American crotalid snake, while S. dispersa grouped with other bird-transmitted species. The available dataset failed to resolve the evolutionary relationships among four major branches into which all Sarcocystidae and Isospora spp. were split. However, within these branches, the phylogenetic relationships of the majority of analysed members of the genus Sarcocystis reflected coevolution with their final, rather than intermediate hosts.

Animals↗
PubMed1998

RNA editing in the free-living bodonid Bodo saltans.

In parasitic kinetoplastid protozoa, mitochondrial (mt) mRNAs are post-transcriptionally edited by insertion and deletion of uridylate residues, the information being provided by guide (g) RNAs. In order to further explore the role and evolutionary history of this process, we searched for editing in mt RNAs of the free-living bodonid Bodo saltans. We found extensive editing in the transcript for NADH dehydrogenase (ND) subunit 5, which is unedited in trypanosomatids. In contrast, B.saltans cytochrome c oxidase (cox) subunit 2 and maxicircle unidentified reading frame (MURF) 2 RNAs display limited editing in the same regions as their trypanosomatid counterparts. A putative intramolecular cox2 gRNA and the gene for gMURF2-I directing the insertion of only one U in the 5' editing domain of MURF2 RNA, are conserved in B.saltans. This lends (further) evolutionary support to the proposed role of these sequences as gRNAs. Phylogenetic analysis showed that B.saltans is more closely related to trypanosomatids than the cryptobiids Trypanoplasma borreli and Cryptobia helicis, in line with the trypanosomatid-like cox2 and MURF2 RNA editing patterns. Nevertheless, other features like the apparent absence of a catenated mtDNA network, are shared with bodonid and cryptobiid species. ND5 RNA editing may represent yet another example of editing 'on the way out' during kinetoplastid evolution, but in view of the fact that cox2 RNA is unedited in T. borreli and C.helicis, we infer that the editing of this RNA may have arisen relatively recently. Our results provide the first examples of RNA editing in a free-living kinetoplastid, indicating that there is no direct link between U-insertion/deletion editing and a parasitic lifestyle.

Amino Acid Sequence↗
PubMed1998

Technetium-99m Q4: a prototype cationic perfusion radiotracer with myocardial washout.

Technetium-99m Q4 is derived from an existing mixed ligand myocardial tracer (99mTc-Q3) by the addition of an ester group to promote myocardial washout. Six subjects with single-vessel coronary disease documented by angiography and/or Q wave myocardial infarction documented by electrocardiography were studied with 99mTc-Q4 injection during exercise and with comparative thallium-201 tomography. Six healthy volunteers were also studied with 99mTc-Q4 imaging following injection at peak exercise. Tomographic images with 99mTc-Q4 and 201Tl each provided correct assessment of the presence or absence of coronary disease in 22 of 30 myocardial segments (73.3%). Six myocardial segments showed defect reversibility with 99mTc-Q4, whereas 14 segments showed reversibility with 201Tl, but the latter included three segments with no angiographic or electrocardiographic evidence of disease. In both normals and subjects with coronary artery disease, significant global washout of 99mTc-Q4 was observed over 4 h. For five patients with angiographic evidence of unrevascularized coronary artery stenosis, the ischemic to normal zone count ratio increased from 0. 782+/-0.107 at 45 min postexercise to 0.891+/-0.115 at 4 h postexercise (P = 0.016), suggesting occurrence of differential washout. It is concluded that addition of an ester group functionality to a previously studied mixed ligand cardiac tracer promotes global and regional myocardial tracer washout. Nevertheless, demonstration of perfusion defect reversibility with comparable frequency to that observed with 201Tl stress and reinjection images, required separate injections of 99mTc-Q4 at peak stress and at rest.

Adult↗
PubMed1998

[Adrenal incidentalomas. Clinical experience].

In the course of two years the authors treated 27 patients with incidentally detected adrenal tumours. Detailed morphological and laboratory examination revealed four cases of non-classical late type adrenogenital syndrome (AGS) and two pheochromocytomas. From the submitted paper ensues that it is essential to provide interdisciplinary comprehensive treatment in departments which have sufficient experience with this problem.

Adrenal Gland Neoplasms↗
PubMed1997

Analysis of ribosomal RNA genes suggests that trypanosomes are monophyletic.

To further investigate the phylogeny of protozoa from the order Kinetoplastida we have sequenced the small subunit (SSU) and a portion of the large subunit (LSU) nuclear rRNA genes. The SSU and LSU sequences were determined from a lizard trypanosome, Trypanosoma scelopori and a bodonid, Rhynchobodo sp., and the LSU sequences were determined from an insect trypanosomatid, Crithidia oncopelti, and a bodonid, Dimastigella trypaniformis. Contrary to previous results, in which trypanosomes were found to be paraphyletic, with Trypanosoma brucei representing the earliest-diverging lineage, we have now found evidence for the monophyly of trypanosomes. Addition of new taxa which subdivide long branches (such as that of T. brucei) have helped to identify homoplasies responsible for the paraphyletic trees in previous studies. Although the monophyly of the trypanosome clade is supported in the bootstrap analyses for maximum likelihood at 97% and maximum parsimony at 92%, there is only a small difference in ln-likelihood value or tree length between the most optimal monophyletic tree and the best suboptimal paraphyletic tree. Within the trypanosomatid subtree, the clade of trypanosomes is a sister group to the monophyletic clade of the nontrypanosome genera. Different groups of trypanosomes group on the tree according to their mode of transmission. This suggests that the adaptation to invertebrate vectors plays a more important role in the trypanosome evolution than the adaptation to vertebrate hosts.

Animals↗
PubMed1997

[Activation of the immune system in colorectal carcinoma and its assessment].

The immune system of the patients with colorectal cancer is activated. Urinary neopterin is an index of this systemic immune activation, reflecting the circulating activity of interferon-gamma. We have measured urinary neopterin excretion in 34 patients with colorectal cancer. This excretion was significantly higher in our patients compared to reference group (325 +/- 267 vs 169 +/- 62 mumol/mol creatinine, neopterin concentrations were considerably higher in Dukes' stage D disease compared with Dukes' stage B and C disease/561 +/- 372 vs 188 +/- 47 and 250 +/- 142 mu/mol creatinine. Increased neopterin detected the presence of metastatic disease with 90% sensitivity and 87.5% specificity. Authors conclude that urinary neopterin measurement may be useful in the staging of colorectal cancer.

Biomarkers, Tumor↗
PubMed1997

Evidence for the anti-hyperlipidaemic activity of the edible fungus Pleurotus ostreatus.

The effects are described of adding either the dried fruiting bodies of the oyster fungus Pleurotus ostreatus, or an ethanolic extract of it, to the diet of normal Wistar male rats and a strain with hereditary hypercholesterolaemia. Addition of the dry oyster fungus to the diet significantly increased, by more than two-fold, the triacylglycerol (TAG) level in the plasma of both groups of rats compared with their respective controls. In contrast, the ethanolic extract did not significantly change TAG levels. Values for total cholesterol and its high- and low-density lipoprotein fractions in the plasma, as well as the calculated atherogenic index, did not show any significant change. Levels of liver cholesterol were significantly lowered by the dried oyster fungus in both hypercholesterolaemic and normal groups of rats, and by the ethanolic extract in normal rats. A significantly increased phospholipid-to-cholesterol ratio in the aortas of both groups of rats, after the administration of either dried oyster fungus or the ethanolic extract of it, suggests a favourable anti-atherogenic effect for both.

Animals↗
PubMed1996

[Soluble interleukin-6 receptors in the serum in multiple myeloma].

BACKGROUND: Infrequent studies, having been published so far, have brought few, partly contradictory, results on the importance of soluble receptor of Interleukin-6 (sIL-6R) in serum in patients with multiple myeloma (MM). The aim of the study was to find out, if there are applicable relations between the levels of sIL-6R and the values of selected clinical and biochemical indices and the levels of some cytokines in serum. METHODS AND RESULTS: The authors analyzed a cohort of 50 patients suffering from MM (age median 64 years, range 34-83 years, ratio of men versus women 1.2:1.0). The soluble IL-6R and other cytokines were examined by ELISA assay, clinical stages of the disease were evaluated according to Durie-Salmon and Bataille. Increased values of sIL-6R (> 90 ng/ml) were in 28 (56%) of patients, median value was 87.4 (range 28.3-220 ng/l). Correlation analysis (Pearson test, p < 0.05) proved a statistically significant relation between the levels of sIL-6R and the values of beta 2-microglobulin (S-B2M) and thymidine kinase (S-TK) in serum. There was no relation to the erythrocyte sedimentation velocity, haemoglobin levels, calcium, urea, creatinine, lactate dehydrogenase, albumin, monoclonal immunoglobulin, C-reactive protein, ferritin, IL-1, IL-2, sIL-2R, IL-6, TNF-alfa, and the occurrence of myeloma plasmocytes in bone marrow. No differences were found between the patients with normal values of S-B2M (< 3 ng/ml) and plasmocytes in bone marrow (< 5%) in comparison with the groups of patients with increased values (3-6, > 6 ng/ml and > 20%, respectively). There was no statistically significant relation of the levels of sIL-6R to clinical stages of MM (1-3) and the degree of activity of the disease. CONCLUSIONS: Increased values of sIL-6R, detected in more than a half of the cohort, were, with the exception of S-B2M, S-TK and massive infiltration of bone marrow by myeloma plasmocytes, in no applicable relation to selected biochemical indices, to the level of some cytokines and to the degree of advancement and activity of the disease.

Adult↗
PubMed1996

Phylogeny of trypanosomes as inferred from the small and large subunit rRNAs: implications for the evolution of parasitism in the trypanosomatid protozoa.

Sequences of the small rRNA genes and partial sequences of the large rRNA genes were obtained by PCR amplification from a variety of vertebrate trypanosomes. The trypanosome species and hosts included Trypanosoma avium from a bird, T. rotatorium from an amphibian, T. boissoni from an elasmobranch, T. triglae from a marine teleost and T. carassii from a freshwater teleost. Phylogenetic relationships among these species and other representatives of the family Trypanosomatidae were inferred using maximum likelihood, maximum parsimony and evolutionary parsimony. The trypanosomatid tree was rooted using rRNA sequences from two species from the suborder Bodonina. All methods showed that the mammalian parasite, Trypanosoma brucei, constitutes the earliest divergent branch. The remaining trypanosomes formed a monophyletic group. Within this group, the bird trypanosome was grouped with T. cruzi, while the elasmobranch trypanosome and the two fish trypanosome species formed a group with an affinity to T. rotatorium. Our results provide no evidence for co-evolution of trypanosomatids and their hosts, either vertebrate or invertebrate. This suggests that evolution of trypanosomatids was accompanied by secondary acquisitions of hosts and habitats.

Animals↗
PubMed1995

Analysis of kinetoplast DNA of freshwater fish trypanosomes.

The sequences of 10 conservative regions (CR) of minicircles of 6 selected isolates of freshwater fish trypanosomes have typical organization of this region with high degree of sequence conservation. The comparison with CRs of other trypanosomatids showed that freshwater fish trypanosomes represent a compact separate group within the genus Trypanosoma. The alignment of all sequences obtained revealed, however, the existence of 2 types of CRs in sequenced minicircles, with the differences concentrated in a short region. Taxonomic consequences of these results are discussed.

Animals↗