Dalibor Titera

Publications (8) View all

• Article: A new low-cost procedure for detecting nucleic acids in low-incidence samples: a case study of detecting spores of Paenibacillus larvae from bee debris.

  Stepan Ryba, Pavel Kindlmann, Dalibor Titera, Marcela Haklova, Pavel Stopka
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  ABSTRACT: American foulbrood, because of its virulence and worldwide spread, is currently one of the most dangerous diseases of honey bees. Quick diagnosis of this disease is therefore vitally important. For its successful eradication, however, all the hives in the region must be tested. This is time consuming and costly. Therefore, a fast and sensitive method of detecting American foulbrood is needed. Here we present a method that significantly reduces the number of tests needed by combining batches of samples from different hives. The results of this method were verified by testing each sample. A simulation study was used to compare the efficiency of the new method with testing all the samples and to develop a decision tool for determining when best to use the new method. The method is suitable for testing large numbers of samples (over 100) when the incidence of the disease is low (10% or less).
  Journal of Economic Entomology 10/2012; 105(5):1487-91. · 1.70 Impact Factor
• Article: In vitro inhibitory activity of essential oil vapors against Ascosphaera apis.

  Pavel Kloucek, Jakub Smid, Jaroslav Flesar, Jaroslav Havlik, Dalibor Titera, Vojtech Rada, Ondrej Drabek, Ladislav Kokoska
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  ABSTRACT: This work evaluates the in vitro inhibitory activity of 70 essential oils (EOs) in the vapor phase for the control of Chalkbrood disease caused by Ascosphaera apis Maassen ex Claussen (Olive et Spiltoir). Two wild strains isolated from infected honey bee colonies together with one standard collection strain were tested by the microatmosphere method. From 70 EOs, 39 exhibited an antifungal effect against A. apis standard and wild strains. The greatest antifungal action was observed for EO vapors from Armoracia rusticana, followed by Thymus vulgaris, Cymbopogon flexosus, Origanum vulgare and Allium sativum. An investigation of chemical composition by GC-MS revealed, that the most active EOs contained allyl isothiocyanate, citral, carvacrol and diallyl sulfides as the main constituents. The chemical composition plays a key role, as activities of different EOs from the same botanical species were different according to their composition.
  Natural product communications 02/2012; 7(2):253-6. · 1.24 Impact Factor
• Article: In vitro growth-inhibitory effect of plant-derived extracts and compounds against Paenibacillus larvae and their acute oral toxicity to adult honey bees.

  Jaroslav Flesar, Jaroslav Havlik, Pavel Kloucek, Vojtech Rada, Dalibor Titera, Michal Bednar, Michal Stropnicky, Ladislav Kokoska
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  ABSTRACT: In total, 26 natural compounds of various chemical classes (flavonoids, alkaloids, terpenoids) and 19 crude extracts from selected plants were tested in vitro for antibacterial activity against three strains of P. larvae, the causal agent of American Foulbrood Disease of honey bees (AFB) by the broth microdilution method. Among the individual substances, sanguinarine (MIC 4 microg/ml), followed by thymoquinone, capsaicin, trans-2-hexenal and nordihydroguaiaretic acid (MIC 4-32 microg/ml) possessed the strongest antibacterial effect. In case of extracts, common hop (Humulus lupulus L.) and myrtle (Myrtus communis L.) methanolic-dichloromethane extracts exhibited the highest growth-inhibitory effect with MICs ranging from 2 to 8 microg/ml. Acute oral toxicity of the most active natural products was determined on adult honey bees, showing them as non-toxic at concentrations as high as 100 microg peer bee. Our study leads to identification of highly potent natural products effective against AFB in vitro with very low MICs compared to those reported in literature, low toxicity to adult honey bees and commercial availability suggesting them as perspective, low cost and consumer-acceptable agents for control of AFB.
  Veterinary Microbiology 09/2010; 145(1-2):129-33. · 3.33 Impact Factor
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  Available from: cnrs.fr

  Article: A PCR method of detecting American Foulbrood (Paenibacillus larvae) in winter beehive wax debris.

  Stepan Ryba, Dalibor Titera, Marcela Haklova, Pavel Stopka
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  ABSTRACT: The objective of this work was to create a fast and sensitive method of detecting Paenibacillus larvae from beehive debris based on PCR that does not require long-lasting cultivation steps. Various methods of extracting spores from beehive debris were compared: the original method of extraction of spores into toluene, and alternative spore extraction methods into Tween 80, into water, into isopropanol and into 95% ethanol. Isolation of DNA from various spore extractions was evaluated too. Best results were provided by isolation of DNA using the QIAamp DNA Mini Kit, without heat treatment. DNA of spores was detected by PCR from 0.25 g of beeswax debris, with the detected titer of 10(5) in 1g according to the cultivation tests.
  Veterinary Microbiology 07/2009; 139(1-2):193-6. · 3.33 Impact Factor
• Article: Solid phase microextraction and gas chromatography with ion trap detector (GC-ITD) analysis of amitraz residues in beeswax after hydrolysis to 2,4-dimethylaniline.

  Jan Lenícek, Milan Sekyra, Andrea Rychtecká Novotná, Eva Vásová, Dalibor Titera, Vladimír Veselý
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  ABSTRACT: An analytical method for the determination of amitraz residues in beeswax after hydrolysis to 2,4-dimethylaniline is reported. It consists of wax extraction with an acid buffer solution, head space solid phase microextraction and GC-ITD analysis. The limit of determination is 1 ng g(-1). Wax samples from beekepers and commercial foundations were analysed, content of residues varied from <1 to 20.5 ng g(-1).
  Analytica chimica acta 06/2006; 571(1):40-4. · 4.31 Impact Factor