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Skocaj M, Bakrac B, Krizaj I, Macek P, Anderluh G, Sepcic K. The Sensing of Membrane Microdomains Based on Pore-Forming Toxins. Curr Med Chem 2013. [DOI: 10.2174/092986713804910094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Macek P, Sanchez-Salas R, Rozet F, Barret E, Galiano M, Hanus T, Cathelineau X. Prostate-Sparing Radical Cystectomy for Selected Patients with Bladder Cancer. Urol Int 2013; 91:89-96. [DOI: 10.1159/000348332] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 01/18/2013] [Indexed: 11/19/2022]
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Sklenář P, Kučerová A, Macek P, Macková J. The frost-resistance mechanism in páramo plants is related to geographic origin. NEW ZEALAND JOURNAL OF BOTANY 2012; 50:391-400. [PMID: 0 DOI: 10.1080/0028825x.2012.706225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Ahallal Y, Barret E, Sanchez-Salas R, Macek P, Galiano M, Cathala N, Prapotnich D, Mombet A, Rozet F, Cathelineau X. Cancer de prostate localisé à faible risque : impact psychologique et qualité de vie des patients en fonction de la prise en charge. Prog Urol 2012. [DOI: 10.1016/j.purol.2012.08.164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Macek P, Bodnarova M, Zavada J, Jezek P, Pavlik I, Slany M, Havelkova M, Stork J, Duskova J, Hanus T, Kocvara R. Mycobacterium marinum Epididymoorchitis: Case Report and Literature Review. Urol Int 2011; 87:120-4. [DOI: 10.1159/000328220] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 04/07/2011] [Indexed: 11/19/2022]
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Savdie R, Yuen C, Stricker P, Macek P, Jagavkar R, Pe Benito R, Haynes A. MP-16.19: High Dose Rate Brachytherapy Compared to Open Radical Prostatectomy for the Treatment of High-Risk Prostate Cancer: 10 Year Biochemical Relapse-Free Survival. Urology 2009. [DOI: 10.1016/j.urology.2009.07.1317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Safarík L, Novák K, Pesl M, Fogel K, Sedlácek J, Macek P, Dvorácek J. [Laparoscopic pyeloplasty in adults--mid-term results in 32 laparoscopic pyeloplasties during 2003-2008]. ROZHLEDY V CHIRURGII : MESICNIK CESKOSLOVENSKE CHIRURGICKE SPOLECNOSTI 2009; 88:142-146. [PMID: 19526947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Pyeloureteric iunction obstruction is the most common inborn error of the upper urinary pathways. In the time of routine prenatal ultrasound examination, this disease is discovered in the child's age, when it is treated most frequently. Publication summarizes the results of modern laparoscopic management in the adults, who had not been diagnosed previously and symptoms occurred many years after their birthdate. The surgical treatment has been changed in the approach, but not the goal of desobtruction. The results in the adults are influenced not only by the operation technique, but also by the length of time the obstruction lasted and by the number and severity of the inflammatory changes.
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Safarík L, Novák K, Babjuk M, Pesl M, Macek P, Dvorácek J. [Outcomes of transperitoneal laparoscopic nephrectomy for renal adenocarcinoma]. ROZHLEDY V CHIRURGII : MESICNIK CESKOSLOVENSKE CHIRURGICKE SPOLECNOSTI 2008; 87:601-604. [PMID: 19209515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Laparoscopic radical nephrectomy (LRN) is method of choice in malignant renal tumors (RCC) stage T1-3. Procedure has proved to be technically safe with low post-operative morbidity and standard oncological results, provided the patients are secondaries free in the time of surgery, and there was no positive margin in resected tissue. There was no recurrence even after 6 years of follow-up. The most influential variables regarding the survival of patients postoperatively were: presence of metastases in the time of surgery p <0.0001, pathological grade p < 0.001, stage p < 0.018 and p < 0.046, respectively, if the tumors were 4 cm and bigger. It could be concluded, that laparoscopic way of removing the tumor with the kidney has proved the same oncological results even in the mid-term follow-up, if compared with classical open surgery done lege artis.
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Macek P, Novák K, Hanus T, Babjuk M, Pesl M, Safarík L, Fógel K, Soukup V, Dvorácek J, Sedlácek J, Stolz J, Capoun O. [Analysis of results of percutaneous nephrolithotomies]. CASOPIS LEKARU CESKYCH 2007; 146:809-812. [PMID: 18020017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
BACKGROUND Percutaneous nephrolithotomy is an effective less invasive method for the treatment of nephrolithiasis. Authors retrospectively analysed results of this procedure performed in a single centre (Department of Urology, General University Hospital, Prague) from January 2005 till June 2007. METHODS AND RESULTS Patients were acquired by an analysis of operating reports performed over a period January 2005 till June 2007 and subsequently a retrospective analysis of electronic and paper patient's records was carried out. Percutaneous nephrolithotomy was performed in 150 patients. Of those, 117 (78%) patients underwent primary and 33 (21.3%) secondary procedure. Analysed group consisted of 85 (56.7%) men and 65 (43.3%) women. Right-sided procedure was performed in 46% (69 times) and left-sided in 54% (81 times) of cases. Mean patient's age was 52.9 years (SD +/- 16.3). Mean stone size was 18.3 (SD +/- 9.5) mm. Staghorn calculi were present in 19 (12.7%) patients and 77 (51.3%) patients had more than 1 stone. Intracorporeal lithotripsy was necessary in 82 (54.7%) cases. Seventy eight (52.9%) patients were stone free after the procedure. There were 24 (16%) patients with an anatomic abnormality of upper urinary tract. The most common (in 64.3%) component in analysed stones was a calcium oxalate. CONCLUSIONS The amount of stone free patients is rather lower compared to the literature results. However, definitive results are always affected by auxiliary procedures (mainly extracorporeal shock wave lithotripsy), which are not included in the analysis.
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Safarík L, Novák K, Sedlácek J, Macek P, Pesl M, Sobotka R, Dvorácek J. [Progress of laparoscopic surgery in adults at the Department of Urology of the First Faculty of Medicine and General Teaching Hospital]. CASOPIS LEKARU CESKYCH 2007; 146:806-808. [PMID: 18020016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Laparoscopy is the most modern operative technique, the main advantage of which is the least invasivity. In urology, the laparoscopy has won its yield only in nineties of 20th century, but it was in urology, where the robots were launched as first, and nowadays using them it is possible to perform ablative/reconstructive surgery in a tiny intracorporeal space. The price of laparoscopic operations is high and has been the only limit up to now, but technical approaches and indications have already been fixed.
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Potrich C, Tomazzolli R, Dalla Serra M, Anderluh G, Malovrh P, Macek P, Menestrina G, Tejuca M. Cytotoxic Activity of a Tumor Protease-Activated Pore-Forming Toxin. Bioconjug Chem 2005; 16:369-76. [PMID: 15769091 DOI: 10.1021/bc049873z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Equinatoxin II is a pore forming toxin produced by the sea anemone Actinia equina. It is able to kill very unspecifically most cell types by the membrane-perturbing action of an amphiphilic alpha-helix located at its N-terminal. A normally active N-terminal mutant, containing one single cys in the amphiphilic alpha-helix, becomes totally inactive when it is bound to avidin via a biotinylated linker. By choosing, as a linker, a peptide containing a tumor protease cleavage site, we were able to construct an enzymatically activable conjugate which should be selective for tumor cells. The introduced cleavage site was designed in order to be digested by both cathepsin B and matrix metalloproteases (MMPs). We confirmed that this conjugate could be activated in vitro by cathepsin B and MMPs. After having measured the enzymatic activity of fibrosarcoma and breast carcinoma cells, we analyzed the cytotoxic effect of the conjugate on the same lines and on human red blood cells (HRBC) as controls. We found that the conjugate was activated, at least in part, by the tumor cell lines used, whereas it was inactive on HRBC. That the activation process was dependent on the enzymatic action of cathepsin B and MMPs, was indicated by three lines of evidence: (1) binding occurred normally on all type of cells including HRBC which however were insensitive being devoid of enzymes; (2) the cytotoxic effect correlated with the amount of cathepsin B activity expressed by the cells; (3) conjugate activation was reduced by specific inhibitors of cathepsin B and MMPs. These results demonstrate the possibility of tumor cell killing by a pore-forming toxin conjugate specifically activated by tumor proteases.
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Förstl M, Stepánová V, Buchta V, Kalousek I, Spacek J, Veselský Z, Macek P, Chrzová M. [Chlamydia infections in urogenital tract--application of direct immunofluorescence in the diagnostics of Chlamydia trachomatis in the East Bohemian Region of Czech Republic during 1997-2003]. CESKA GYNEKOLOGIE 2005; 70:128-33. [PMID: 15918267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
OBJECTIVE The aim of the study was an evaluation of results of Chlamydia trachomatis antigen detection by means of direct immunofluorescence in samples from patients suspected from this infection. DESIGN Retrospective study. SETTING Institute of clinical microbiology, University Hospital and Medical Faculty of Charles University, Hradec Králové. METHODS Samples from females were swabs from uterine cervix, vagina and urethra, from male urethral swabs; moreover conjunctival swabs, bronchoalveolar irrigation, lower respiratory tract aspirates and sputum. Samples were fixed and "dyed" with monoclonal specific antibody labeled by fluorescent dye in the lab with a commercial diagnostic kit and they were evaluated microscopically after adding a drop of glycerol and covering with a top slide. RESULTS Within a group of 6126 samples from patients suspected from Chlamydia infection we have found positivity in 14.4%. Of this subgroup 14.1% in samples from genitourinary tract of females and 15.2% in males, 14.1% from conjunctival swabs and 3.7% from lower respiratory tract. According to an age differentiation, positive samples in individual life-decades from genitourinary tract were 0-13-14.4-13.9-13.9 and in females over 60 13.9%. In males the corresponding walues were 0-21.4-15.1-16-13.4 and those over 60 years 16%. So, the highest positivity in our region has been detected in samples from young men aged 20-30, where it is nearly two-fold higher comparison to age-matched females. CONCLUSION Direct detection of Chlamydia trachomatis antigen with immunofluorescence method still remains a reliable diagnostic tool. But for a control or confirmation of disputable results it is inconditionally necessary to have at least one more method available, e.g. PCR.
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Prosvic P, Dulícek P, Odrázka K, Navrátilová J, Morávek P, Macek P, Veselský Z. [Asynchronous occurrence of three neoplastic diseases: chronic B-cell lymphatic leukemia, renal carcinoma and prostatic adenocarcinoma]. ROZHLEDY V CHIRURGII : MESICNIK CESKOSLOVENSKE CHIRURGICKE SPOLECNOSTI 2003; 82:583-6. [PMID: 14686258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Authors present a case of three asynchronous malignancies in man working life-long in chemical industry. Course of diseases and their treatment are described: B chronic lymphatic leukaemia (B-CLL) (age of 55), conventional clear cell renal carcinoma (CRCC) (age of 61) and adenocarcinoma of prostate (CaP) (age of 72). B-CLL treatment was chlorambucil for 2 years and follow-up subsequently. CRCC treatment was radical transperitoneal nephrectomy. Due to locally advanced CaP bilateral orchiectomy and radical external beam radiotherapy were performed. Patients is alive 30 months without any signs of any malignity. Incidence of multiple malignancies and particularly triplicities are discussed in this article. Authors point out pertinence of radical therapeutic approach also in multiple malignancies and oncological screening not only in patients with heamatological malignancy, but considering it in all tumours.
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Veselský Z, Macek P, Rýdel L, Prosvic P, Förstl M, Plísek S. [Fournier's gangrene]. ROZHLEDY V CHIRURGII : MESICNIK CESKOSLOVENSKE CHIRURGICKE SPOLECNOSTI 2002; 81:357-9. [PMID: 12197171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The authors present their own experiences with diagnostics and treatment of men with necrotising fasciitis of the scrotum (Fournier's gangrene). During 1995-2001 8 men were treated for the above diagnosis at the Clinic of Urology, Faculty Hospital in Hradec Králové. Six cases were patients with diabetes type II, in one patient we found during basic examinations a large tumour of the sigmoid and one patient was 7 days after total scrotal orchiectomy (because of prostatic adenocarcinoma). Repeated open revision under general anaesthesia was performed in all men with necessary necrectomy, testicles were intact (except a patient after orchiectomy). The infection was spread into the hypogastric area in two patients and in one patient spontaneous rupture of bulbar urethra occurred. By a combination of antibiotic therapy and repeated necrectomies, open wound healing and wet compresses we achieved cure of infection and granulations, which made final scrotal plastic surgery possible. From microbiological point of view it was mixed aerobic and anaerobic flora.
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Pasic L, Sepcic K, Turk T, Macek P, Poklar N. Characterization of parazoanthoxanthin A binding to a series of natural and synthetic host DNA duplexes. Arch Biochem Biophys 2001; 393:132-42. [PMID: 11516170 DOI: 10.1006/abbi.2001.2469] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Parazoanthoxanthin A is a fluorescent yellow nitrogenous pigment of the group of zoanthoxanthins, which show a broad range of biological activity. These include, among others, the ability to bind to DNA. In this study we have used a variety of spectroscopic (intrinsic fluorescence emission and UV-spectroscopy) and hydrodynamic techniques (viscometry) to characterize in more detail the binding of parazoanthoxanthin A to a variety of natural and synthetic DNA duplexes in different buffer conditions. Our results reveal the following five significant features: (i) Parazoanthoxanthin A exhibits two modes of DNA binding: One binding mode exhibits properties of intercalation, while the second binding mode is predominantly electrostatic in origin. (ii) The apparent binding "site size" for parazoanthoxanthin A near physiological salt concentration (100 mM NaCl) is in the range of 7 +/- 1 base pairs for natural genomic DNA duplexes (calf thymus and salmon testes DNA) and alternating synthetic polynucleotides (poly[d(AT)]. poly[d(AT)] and poly[d(GC)]. poly[d(GC)]). A slightly larger apparent binding site size of 9 +/- 1 bp was obtained for parazoanthoxanthin A binding to the synthetic homopolymer poly[d(A)]. poly[d(T)]. (iii) Near physiological salt concentration (100 mM NaCl) parazoanthoxanthin A binds with the same approximate binding affinity of 2-5 x 10(5) M(-1) to all DNA polymers studied. (iv) At low salt concentration, parazoanthoxanthin A preferentially binds alternating poly[d(AT)]. poly[d(AT)] and poly[d(GC)]. poly[d(GC)] host duplexes. (v) Parazoanthoxanthin A inhibits DNA polymerase in vitro.
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Sepcić K, Mancini I, Vidic I, Franssanito R, Pietra F, Macek P, Turk T. Antibacterial and anticholinesterase activities of aplysamine-4, a bromotyrosine-derived metabolite of a Red Sea marine sponge. JOURNAL OF NATURAL TOXINS 2001; 10:181-91. [PMID: 11491458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Aplysamine-4, a metabolite of likely bromotyrosine biogenesis, was isolated from an unidentified verongid sponge from the Red Sea. The compound was identified by heteronuclear magnetic resonance experiments, and by electrospray ionization tandem mass spectrometry. The compound exhibited moderate inhibitory activity on several Gram positive and Gram negative bacteria, and was also found to be a non-competitive reversible inhibitor of acetylcholinesterase. At pH 7.4, a Ki value of 16 and 2 microM was determined with electric eel and insect recombinant acetylcholinesterase, respectively. A deprotonated form of aplysamine-4 was obtained by alkaline treatment of the natural compound and it was shown to be less active than the protonated form.
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Veselský Z, Macek P, Navrátil P, Fixa P, Psohlavec J, Förstl M. [Comparison of 2 methods of diagnosis of changes in transplanted kidneys in the early postoperative period: biopsy vs dynamic scintigraphy of the graft]. ROZHLEDY V CHIRURGII : MESICNIK CESKOSLOVENSKE CHIRURGICKE SPOLECNOSTI 2001; 80:361-3. [PMID: 11505690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Renal transplantation is at present a standard therapeutic method in chronic renal insufficiency. For a favourable development of the graft some investigated criteria are of basic importance: basic diagnosis which led to renal failure, period of dialyzation treatment, high standard collection and perfusion and early diagnosis of the rejection episode. Non-invasive diagnostic methods of the rejection episode are always indirect and correlate with histologically confirmed rejection, depending on the period of transplantation in 10-90% patients. Indirect diagnosis is based in particular on a rise of the creatinemia, decline of glomerular filtration, fluid retention variations of blood pressure and increase of the Doppler assessed index of resistance (IR) in the peripheral veins of the graft [1]. For many years the role of nuclear diagnostics are tested. The disadvantage of direct diagnosis--biopsy--is increased haemorrhage and loss of the graft [1, 2, 3, 4]. The greatest problem is the differentiation of acute (cellular) rejection as compared with acute tubular necrosis during the initial days after transplantation. The authors describe their experience with 81 biopsies in the course of 3 years in patients during the first 10 days after transplantation, comparison with dynamic scintigraphy of the graft. Their attention is focused on the technique and risks of renal biopsy.
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Veselský Z, Navrátil P, Steiner I, Macek P, Psohlavec J, Forstl M, Podhola M. [Aspergillosis--a rare complicating disease in patients after renal transplantation]. ROZHLEDY V CHIRURGII : MESICNIK CESKOSLOVENSKE CHIRURGICKE SPOLECNOSTI 2001; 80:364-6. [PMID: 11505691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The authors submit a detailed analysis of the death of a 42-year-old man after a second renal transplantation. The patient died with symptoms of cardiac failure in a septic condition of obscure etiology where even detailed examination did not provide a timely answer as regards the lethal pathogen. Aspergillus fumigatus is a rare lethal pathogen. Despite this it is, as all opportune infections, for patients with immunosuppressive therapy a serious life threatening infection [1, 2]. In a group of 650 transplantations performed since 1961 in Hradec Králové it is the first death caused by generalized Aspergillus infection.
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Athanasiadis A, Anderluh G, Macek P, Turk D. Crystal structure of the soluble form of equinatoxin II, a pore-forming toxin from the sea anemone Actinia equina. Structure 2001; 9:341-6. [PMID: 11525171 DOI: 10.1016/s0969-2126(01)00592-5] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Membrane pore-forming toxins have a remarkable property: they adopt a stable soluble form structure, which, when in contact with a membrane, undergoes a series of transformations, leading to an active, membrane-bound form. In contrast to bacterial toxins, no structure of a pore-forming toxin from an eukaryotic organism has been determined so far, an indication that structural studies of equinatoxin II (EqtII) may unravel a novel mechanism. RESULTS The crystal structure of the soluble form of EqtII from the sea anemone Actinia equina has been determined at 1.9 A resolution. EqtII is shown to be a single-domain protein based on a 12 strand beta sandwich fold with a hydrophobic core and a pair of alpha helices, each of which is associated with the face of a beta sheet. CONCLUSIONS The structure of the 30 N-terminal residues is the largest segment that can adopt a different structure without disrupting the fold of the beta sandwich core. This segment includes a three-turn alpha helix that lies on the surface of a beta sheet and ends in a stretch of three positively charged residues, Lys-30, Arg-31, and Lys-32. On the basis of gathered data, it is suggested that this segment forms the membrane pore, whereas the beta sandwich structure remains unaltered and attaches to a membrane as do other structurally related extrinsic membrane proteins or their domains. The use of a structural data site-directed mutagenesis study should reveal the residues involved in membrane pore formation.
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Poklar N, Völker J, Anderluh G, Macek P, Chalikia TV. Acid- and base-induced conformational transitions of equinatoxin II. Biophys Chem 2001; 90:103-21. [PMID: 11352270 DOI: 10.1016/s0301-4622(01)00131-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We have investigated the acid- and base-induced conformational transitions of equinatoxin II (EqTxII), a pore-forming protein, by a combination of CD-spectroscopy, ultrasonic velocimetry, high precision densimetry, viscometry, gel electrophoresis, and hemolytic activity assays. Between pH 7 and 2, EqTxII does not exhibit any significant structural changes. Below pH 2, EqTxII undergoes a native-to-partially unfolded transition with a concomitant loss of its rigid tertiary structure and the formation of a non-native secondary structure containing additional alpha-helix. The acid-induced denatured state of EqTxII exhibits a higher intrinsic viscosity and a lower adiabatic compressibility than the native state. Above 50 degrees C, the acid-induced denatured state of EqTxII reversibly denatures to a more unfolded state as judged by the far UV CD spectrum of the protein. At alkaline pH, EqTxII undergoes two base-induced conformational transitions. The first transition occurs between pH 7 and 10 and results in a partial disruption of tertiary structure, while the secondary structure remains largely preserved. The second transition occurs between pH II and 13 and results in the complete loss of tertiary structure and the formation of a non-native, more alpha-helical secondary structure. The acid- and base-induced partially unfolded states of EqTxII form water-soluble oligomers at low salt, while at high salt (> 350 mM NaCl), the acid-induced denatured state precipitates. The hemolytic activity assay shows that the acid- and base-induced denatured states of EqTxII exhibit significantly reduced activity compared to the native state.
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Lahajnar G, Macek P, Zupancic I. Suppression of red cell diffusional water permeability by lipophilic solutes. Bioelectrochemistry 2000; 52:179-85. [PMID: 11129241 DOI: 10.1016/s0302-4598(00)00100-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The inhibitory effect of a series of neutral lipophilic solutes (methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-amylalcohol, n-hexanol, diethylether, nitrobenzene, and pyridine) on the diffusional water permeability (Pd, tot) of bovine erythrocyte membrane at 25 degrees C was studied in comparison to that of p-chloromercuri benzoate (pCMB). Permeability data were obtained by measuring the transmembrane diffusional water exchange time tau(exch) using an 1H-T2 NMR technique. Maximal inhibition by approximately 50% of Pd, tot was produced by 2 mM pCMB which completely blocked the membrane water channels in 20 min, hence suggesting the channel-to-lipid diffusional water permeability ratio of about 1:1. Furthermore, the maximal inhibitory effect of pCMB in combination with the lipophilic solutes was lower than that of pCMB alone. As pCMB does not interfere with the lipid bilayer, and provided that it blocks the water channels in solute presence as well, this confirms that the solutes induce an increase in the lipid-mediated background water permeability contribution (Pd, lipid) by the formation of aqueous leaks in the membrane hydrophobic barrier. However, faster but less efficient in permeability inhibition than pCMB (either alone or combined with solutes) were the lipophilic solutes alone. Taken together, the results indicate that the lipophilic solutes suppress the membrane total permeability Pd, tot by two opposing effects: a reduction of its channel-mediated part (Pd, channel) to the extent exceeding that of a simultaneous Pd, lipid increase. The inhibitory potency of the solutes tested appears to be correlated with their solubility in the membrane medium.
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Grgicević D, Balija M, Pirc-Tiljak D, Mihaljević I, Gjenero-Margan I, Zupancić-Salek S, Macek P. Decreasing risk of viral transfusion-transmitted diseases in Croatia. Croat Med J 2000; 41:191-6. [PMID: 10853051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
AIM To assess the risk of viral transfusion-transmitted infections in Croatia. METHODS The following parameters were analyzed: frequency of blood donations repeatedly reactive for HBsAg and anti-HCV (1993-1999); blood donations confirmed positive for HBsAg and anti-HCV (1997-1999), anti-HIV1/2, and syphilis reactivity (1993-1999); number of registered patients with hepatitis B and C; transfusion-associated hepatitis B and hepatitis C; and frequency of HBV, HCV and HIV markers in patients with congenital bleeding disorders (1993-1998). RESULTS The frequency of repeatedly reactive HBsAg and anti HCV markers and confirmed positive HBsAg, anti-HCV, and syphilis markers in donors blood decreased during the study, whereas the frequency of anti-HIV1/2 positivity did not change. The frequency of confirmed positive donors in 1999 was 0.068% for HBsAg, 0.035% for anti HCV, 0.002% for anti HIV1/2, and 0.0056% for syphilis. The number of patients with hepatitis B, hepatitis C, and transfusion-associated hepatitis B and C steadily decreased during the 1993-1998 period. The number of transfusion-associated hepatitis patients leveled off in 1997. From the beginning of the follow-up of AIDS patients in 1987, only 7 (2%) of hemophiliacs have been HIV-infected, all before 1990 and due to non-inactivated coagulation factor concentrates. There were no cases of transfusion-associated HIV2 infection in patients with congenital bleeding disorders or transfusion-associated HIV1 infection through transfusion of labile blood components. CONCLUSION The safety of transfusion therapy in Croatia has improved, and the present risks of viral transfusion transmitted diseases are very low.
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Anderluh G, Podlesek Z, Macek P. A common motif in proparts of Cnidarian toxins and nematocyst collagens and its putative role. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1476:372-6. [PMID: 10669802 DOI: 10.1016/s0167-4838(99)00237-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
In Cnidarians, cnidoblast cells contain organelles called cnidocysts, which are believed to be the product of an extremely complex regulated secretory pathway. When matured, these stinging organelles are capable of storing and delivering toxins. We hypothesized that translated nematocyst proteins might comprise specific sequences serving as signals in sorting to the organelle. A sodium channel neurotoxin from the sea anemone Actinia equina was cloned and the toxin precursor sequence was compared to those of nematocyst collagens, pore-forming toxins and ion channel neurotoxins. It was found that all the analyzed sequences possess a highly conserved stretch of nine amino acid residues ending with Lys-Arg N-terminally of the mature region.
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Anderluh G, Barlic A, Potrich C, Macek P, Menestrina G. Lysine 77 is a key residue in aggregation of equinatoxin II, a pore-forming toxin from sea anemone Actinia equina. J Membr Biol 2000; 173:47-55. [PMID: 10612691 DOI: 10.1007/s002320001006] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Among eighteen point mutants of equinatoxin II produced in E. coli, containing a single cystein substitution at variable position, EqtIIK77C was chosen for its peculiar properties. It was almost 100 times less hemolytic than the wild-type, but its hemolytic activity could be restored by chemical modification of the thiol group, provided that a positive charge was reintroduced. This indicates that a positive charge at this position is necessary for toxin activity. The mutant formed larger pores as compared to the wild type, but displayed the same cation selectivity. The pores reverted to normal size upon reintroduction of the positive charge. The conformation of EqtIIK77C and its binding to lipid membranes, either vesicles or red blood cells, was almost normal. However the kinetics of calcein release from lipid vesicles was substantially slower than that of the wild-type. Taken together with the different size of the pore formed, this is an indication that mutation of Lys77 --> Cys influences the normal development of the aggregate which is required for assembling the functional pore.
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Sepcić K, Musevic I, Lahajnar G, Turk T, Macek P. AFM imaging of surface adsorbed polymeric 3-alkylpyridinium salts from the marine sponge Reniera sarai. Int J Biol Macromol 1999; 26:353-6. [PMID: 10628537 DOI: 10.1016/s0141-8130(99)00106-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Bioactive 3-alkylpyridinium polymers (poly-APS) have recently been isolated from the marine sponge Reniera sarai. Previous results have shown that these molecules in aqueous solutions form supramolecular aggregates with an average hydrodynamic radius of 23 +/- 2 nm. To obtain additional evidences about the shape and the dimensions of poly-APS aggregates, we used atomic force microscopy (AFM) operating in tapping mode. The images clearly showed adsorbed aggregates with a lateral dimension of approximately 40 nm and a thickness of the order of approximately 1 nm. The distribution of volumes of the adsorbed aggregates is very similar to the distribution of hydrodynamic radii as obtained from the dynamic light scattering experiments. The volume distribution of these aggregates shows a maximum at 1750 nm3, which corresponds to a sphere with a radius of 7.5 nm.
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