Summary
IscA/Isa proteins function as alternative scaffolds for the assembly of Fe‐S clusters and/or provide iron for their assembly in prokaryotes and eukaryotes. Isa are usually non‐essential and ...in most organisms are confined to the mitochondrion. We have studied the function of TbIsa1 and TbIsa2 in Trypanosoma brucei, where the requirement for both of them to sustain cell growth depends on the life cycle stage. The TbIsa proteins are abundant in the procyclic form, which contains an active organelle. Both proteins are indispensable for growth, as they are required for the assembly of Fe‐S clusters in mitochondrial aconitase, fumarase and succinate dehydrogenase. Reactive oxygen species but not iron accumulate in the procyclic mitochondrion upon ablation of the TbIsa proteins, but their depletion does not influence the assembly of Fe‐S clusters in cytosolic proteins. In the bloodstream form, which has a downregulated mitochondrion, the TbIsa proteins are non‐essential. The Isa2 orthologue of the anaerobic protist Blastocystis partially rescued the growth and enzymatic activities of TbIsa1/2 knock‐down. Rescues of single knock‐downs as well as heterologous rescues with human Isa orthologues partially recovered the activities of aconitase and fumarase. These results show that the Isa1 and Isa2 proteins of diverse eukaryotes have overlapping functions.
Summary
Trypanosomatids are a very diverse group composed of monoxenous and dixenous parasites belonging to the excavate class Kinetoplastea. Here we studied the respiration of five monoxenous ...species (Blechomonas ayalai, Herpetomonas muscarum, H. samuelpessoai, Leptomonas pyrrhocoris and Sergeia podlipaevi) introduced into culture, each representing a novel yet globally distributed and/or species‐rich clade, and compare them with well‐studied flagellates Trypanosoma brucei, Phytomonas serpens, Crithidia fasciculata and Leishmania tarentolae. Differences in structure and activities of respiratory chain complexes, respiration and other biochemical parameters recorded under laboratory conditions reveal their substantial diversity, likely a reflection of different host environments. Phylogenetic relationships of the analysed trypanosomatids do not correlate with their biochemical parameters, with the differences within clades by far exceeding those among clades. As the S. podlipaevi canonical respiratory chain complexes have very low activities, we believe that its mitochondrion is utilised for purposes other than oxidative phosphorylation. Hence, the single reticulated mitochondrion of diverse trypanosomatids seems to retain multipotency, with the capacity to activate its individual components based on the host environment.
Five newly isolated trypanosomatids were tested for specific mitochondrial enzymatic activities and respiration. The collected data were mapped to phylogeny to see whether there is a correlation between mitochondrial features and phylogeny or not. We concluded that trypanosomatids, in general, possess a mitochondrion that is capable of adjusting to various environments.
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•The trypanosome biodiversity and feeding preferences of tsetse and tabanid flies are presented.•Tsetse, but not tabanid, flies transmit a surprisingly wide spectrum of ...trypanosomes.•Five of eight Trypanosoma spp. identified were encountered for the first time.•Blood meals of ∼1000 forest tsetse flies were examined by high throughput sequencing.•Tsetse flies’ feeding opportunism includes buffaloes, humans, antelopes and suids.
Tsetse and tabanid flies transmit several Trypanosoma species, some of which are human and livestock pathogens of major medical and socioeconomic impact in Africa. Recent advances in molecular techniques and phylogenetic analyses have revealed a growing diversity of previously unidentified tsetse-transmitted trypanosomes potentially pathogenic to livestock and/or other domestic animals as well as wildlife, including African great apes. To map the distribution, prevalence and co-occurrence of known and novel trypanosome species, we analyzed tsetse and tabanid flies collected in the primary forested part of the Dzanga-Sangha Protected Areas, Central African Republic, which hosts a broad spectrum of wildlife including primates and is virtually devoid of domestic animals. Altogether, 564 tsetse flies and 81 tabanid flies were individually screened for the presence of trypanosomes using 18S rRNA-specific nested PCR. Herein, we demonstrate that wildlife animals are parasitized by a surprisingly wide range of trypanosome species that in some cases may circulate via these insect vectors. While one-third of the examined tsetse flies harbored trypanosomes either from the Trypanosoma theileri, Trypanosoma congolense or Trypanosoma simiae complex, or one of the three new members of the genus Trypanosoma (strains ‘Bai’, ‘Ngbanda’ and ‘Didon’), more than half of the tabanid flies exclusively carried T. theileri. To establish the putative vertebrate hosts of the novel trypanosome species, we further analyzed the provenance of blood meals of tsetse flies. DNA individually isolated from 1033 specimens of Glossina spp. and subjected to high-throughput library-based screening proved that most of the examined tsetse flies engorged on wild ruminants (buffalo, sitatunga, bongo), humans and suids. Moreover, they also fed (albeit more rarely) on other vertebrates, thus providing indirect but convincing evidence that trypanosomes can be transmitted via these vectors among a wide range of warm- and cold-blooded hosts.
Due to different biological characteristics of non-colorectal liver metastasizes (NCLM), surgical treatment, especially it´s long term results, is a topic of discussion. The aim of the study was to ...evaluate the single center experience with surgical treatment of NCLM.
Seventy two patients were prospectively included. The average length of time after the primary surgery was 3.9 years (0-8.5 years). RFA prevailed -50 patients (69.4%), resection presenting 30.6%. Preoperative chemotherapeutical downstaging or portal vein embolization was performed on 12 patients (16.7%). Resectable or radiofrequency ablation (RFA) treatable extrahepatic metastasizes were removed in 26 patients (36.1%).
One, three and five years patient survival after the liver resection or RFA was 88.6, 72.5 and 36.9%. The best survival rate was in patients with carcinoid (5 years-100%), breast cancer (5 years-33.8%), renal carcinoma (3 years-44.4% ) and gynecological tumors metastasizes (2 years-72.9%). With regards to long-term survival of patients, we did not find any statistically significant difference between RFA and resection. Patients with extrahepatic metastasizes had worse prognosis (p<0.01).
Liver resection and RFA in NCLM have an unambiguous place in multi-modal curative strategy. The decision for surgical treatment of patients suffering from NCLM, is strictly individual with the aim of achieving qualitative long-term survival.
To find out whether the total tumor mass and post-ablation necrosis volume influence the disease-free survival of patients following radiofrequency ablation (RFA).
Fifty nine patients with RFA of ...primary and secondary tumors were evaluated retrospectively in a four year period. Total liver mass, post-ablation necrosis volume and their ratio were evaluated using computed tomography examination in the relationship with the risk of insufficient tumor ablation and the disease-free patients survival.
A complete ablation was performed in 51 patients, non-ablation in 8 (13.6%) patients. Tumor, necrosis volume were 19.2±19.5, 58.7±44.7mL, respectively. The tumor and necrosis mass ratio was 0.39±0.45. The tumor or necroses mass volume or the tumor/necroses mass ratio had no effect on the patients progression-free survival. Patients with a necrosis volume <25mL had a 10-times higher risk of insufficient ablation (OR=9.9; 95% CI=1.9-51.5; p<0.002) and patients with the tumor/necrosis mass ratio >0.4 had a 8-times higher risk of insufficient ablation (OR=7.9; 95% CI=1.4-44.6; p<0.01).
Necrosis volume after RFA and tumor/necrosis mass ratio are the important factors for insufficient ablation but do not have any influence on the patients progression-free survival.
Portal vein embolization (PVE) may increase the resectability of liver metastases. However, the problem of PVE is insufficient growth of the liver or tumor progression in some patients. The aim of ...this study was to evaluate the significance of commonly available clinical factors for the result of PVE.
Portal vein embolization was performed in 38 patients with colorectal liver metastases. Effects of age, gender, time between PVE and liver resection, oncological therapy after PVE, indocyanine green retention rate test, synchronous, metachronous and extrahepatic metastases, liver volume before and after PVE, increase of liver volume after PVE and the quality of liver parenchyma before PVE on the result of PVE were evaluated.
Liver resection was performed in 23 (62.2%) patients within 1.3 ±0.4 months after PVE. Tumor progression occurred in 9 (23.7%) patients and 6 (15.8%) patients had insufficient liver hypertrophy. Significant clinical factors of PVE failure were number of liver metastases (cut-off - 4; odds ratio - 4.7; p < 0.03), liver volume after PVE (cut-off 1000 cm(3); odds ratio - 5.1; p < 0.02), growth of liver volume after PVE (cut-off 150 cm(3); odds ratio - 18.7; p < 0.002), oncological therapy administered concomitantly with PVE (p < 0.003).
Negative clinical factors of resectability of colorectal cancer liver metastases after PVE included more than four liver metastases, liver volume after PVE < 1000 cm(3), growth of the contralateral lobe by less than 150 cm(3) and concurrent oncological therapy.
In this case report, the authors aim to demonstrate the success of recent methods in the radical treatment of a patient with primary inoperable liver and subsequent colorectal cancer pulmonary ...metastases.
A 75 year old patient with inoperable bulky metastasis in the right hepatic lobe and insufficient future remnant liver volume was indicated for a stage procedure in the liver parenchyma. Embolization of the right branch of the portal vein was first performed with subsequent administration of stem cells into the contralateral liver lobe. Following compensatory growth of the left liver lobe, right-sided hepatectomy was performed with subsequent adjuvant oncological treatment. Six months after the surgery, a metastasis developed in the right pulmonary lobe which was solved by metastasectomy.
The patient, one year after the diagnosis of inoperable liver metastasis, is completely healthy and free of signs of disease recurrence.
A comprehensive oncosurgical approach using up-to-date diagnostic and treatment options may offer patients with metastatic colorectal cancer, radical treatment with the hope of long-term quality survival.
Low energy (0-3 eV) electron attachment to single formic acid (FA) and FA clusters is studied in crossed electron/molecular beam experiments. Single FA molecules undergo hydrogen abstraction via ...dissociative electron attachment (DEA) thereby forming HCOO(-) within a low energy resonance peaking at 1.25 eV. Experiments on the isotopomers HCOOD and DCOOH demonstrate that H/D abstraction occurs at the O-H/O-D site. In clusters, electron attachment is strongly enhanced leading to a variety of negatively charged complexes with the dimer M2(-) (Mtriple bondHCOOH) and its dehydrogenated form M (M-H)(-) as the most abundant ones. Apart from the homologous series containing the non-dissociated (Mn(-)) and dehydrogenated complexes (M(n-1) (M-H)(-), n > or = 1) further products are observed indicating that electron attachment at sub-excitation energies (approximately 1 eV) can trigger a variety of chemical reactions. Among these we detect the complex H2O (M-H)(-) which is interpreted to arise from a reaction initiated in the cyclic hydrogen bonded dimer target. In competition to hydrogen abstraction yielding the dehydrogenated complex M (M-H)(-) the abstracted hydrogen atom can react with the opposite FA molecule forming H2O and HCO with the polar water molecule attached to the closed shell HCOO(-) ion. The FA dimer can thus be used as a model system to study the response of a hydrogen bridge towards dehydrogenation in DEA.
All eukaryotic genomes encode multiple members of the heat shock protein 70 (HSP70) family, which evolved distinctive structural and functional features in response to specific environmental ...constraints. Phylogenetic analysis of this protein family thus can inform on genetic and molecular mechanisms that drive species-specific environmental adaptation. Here we use the eukaryotic pathogen Leishmania spp. as a model system to investigate the evolution of the HSP70 protein family in an early-branching eukaryote that is prone to gene amplification and adapts to cytotoxic host environments by stress-induced and chaperone-dependent stage differentiation. Combining phylogenetic and comparative analyses of trypanosomatid genomes, draft genome of Paratrypanosoma and recently published genome sequences of 204 L. donovani field isolates, we gained unique insight into the evolutionary dynamics of the Leishmania HSP70 protein family. We provide evidence for (i) significant evolutionary expansion of this protein family in Leishmania through gene amplification and functional specialization of highly conserved canonical HSP70 members, (ii) evolution of trypanosomatid-specific, non-canonical family members that likely gained ATPase-independent functions, and (iii) loss of one atypical HSP70 member in the Trypanosoma genus. Finally, we reveal considerable copy number variation of canonical cytoplasmic HSP70 in highly related L. donovani field isolates, thus identifying this locus as a potential hot spot of environment-genotype interaction. Our data draw a complex picture of the genetic history of HSP70 in trypanosomatids that is driven by the remarkable plasticity of the Leishmania genome to undergo massive intra-chromosomal gene amplification to compensate for the absence of regulated transcriptional control in these parasites.
Portal vein embolization (PVE) extends the resecability of liver tumours.The issue of PVE is an insufficient growth of the liver parenchyma or a tumour progression in some patients. We evaluated the ...effect of the volume and the number of liver tumours on the effect of PVE.
PVE was performed in 40 patients with liver tumours due to an insufficient future remnant liver volume. The number and the volume of the tumours were evaluated and compared with the final PVE effect.
In patients without any increase of the liver volume after PVE (n=3) the number and the volume of the tumours before PVE were 2.7±2.1 and 2205.1±2432.7mm3, respectively. In patients with sufficient growth of the liver (n=22) it was 3.8±2.2 (NS) and 1164.9±1392.1mm3 (NS), respectively. In patients with tumour progression (n=11) it was 5.6±2.2 and 6971.4±5189.5mm3, respectively (p<0.04 and p<0.005, respectively). Four patients were treated by radiofrequency ablation only due to worsening of their health state. Patients with >4 foci (OR 4.7) and a tumour volume >400mm3 (OR=13.0) had a higher probability of cancer progression or insufficient growth of the liver tissue. Patients with <6 foci and a tumour volume <3100mm3 had an 87.5% probability of a successful liver hypertrophy after PVE.
The tumour number and volume were crucial for progression of a malignant disease and growth of the liver parenchyma after PVE.
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