Home economics in an oak gall: behavioural and chemical immune strategies against a fungal pathogen in Temnothorax ant nests.

Nest architecture is a fundamental character shaping immune strategies of social insects. The arboreal ant Temnothorax unifasciatus nests in cavities such as oak galls where the entire colony lives in a unique small chamber. In these conditions, physiological and behavioural strategies likely prevail over compartmentalisation and are presumably tuned with colony size. We designed two experiments to study chemical and behavioural immune strategies against the entomopathogenic fungus Metarhizium anisopliae in colonies of different sizes. First, we compared spore germination and length of germinal tubes inside artificial nests, designed to impede the contact between the ants and the fungus, in colonies of different size. In the absence of direct contact, Temnothorax unifasciatus colonies inhibit fungal growth inside their nests, presumably through volatile compounds. The analysis revealed a positive correlation between fungistatic activity and colony size, indicating that workers of smaller colonies do not invest a higher per capita effort in producing such substances compared to larger colonies. Second, we performed a removal experiment of contaminated and non-contaminated items introduced inside the nests of colonies of different size. Small colonies challenged with contaminated fibres showed an increased removal of all the items (both contaminated and non-contaminated) compared to small colonies challenged with non-contaminated fibres only. Conversely, larger colonies moved items regardless of the presence of the spores inside the nest. Colony size qualitatively affected removal of waste items showing a pathogen elicited reaction in small colonies to optimise the reduced workforce, while the removal behaviour in larger colonies revealed to be expressed constitutively.

[Optimization of technological processes for the preparation of tablets with a low content of warfarin by direct compression]. / Optimalizace technologických postupu pro prípravu tablet s nízkým obsahem warfarinu metodou prímého lisování

Warfarin is a rug with an arrow therapeutic index. It is commercially available in the form of tablets with immediate release from many generic manufacturers. Though attempts are being made to replace it with new drugs, in the U.S.A.it is still the antithrombotic agent of the first choice. In the past there were cases when after replacement of the original brand preparation with the generic one, the patient suffered from complications such as the loss of control of anticoagulation and increased frequency of patients visits to the physician. One of the critical parameters of tablets containing an active substance with an arrow therapeutic index (NTI) is content uniformity, which must comply with the pharmacopoeial requirements as well as the strict criteria of regulatory authorities in the validation of the manufacture of the solid dosage form. Content uniformity is affected by a number of factors such as density, particle shape and size distribution, electrostatic charge, and concentration of the individual components. Of the technological parameters, it is mainly the intensity and length of mixing, shape of the mixing vessel and the mixer, the size of the charge, or the degree of filling of the mixing device, etc. This paper deals with the influence of the mixing time and concentration of the drug on the content uniformity of warfarin-containing tablets. In mixing the mixtures of solid substances, where the active substance is included in alow concentration, there occurs the so-called mixing-out and segregation of the active substance. For this reason it is necessary to optimize the period of mixing. This study managed to optimize the mixing time of mixtures prepared with the use of the patented technology of the Veterinary and Pharmaceutical University Brno and further to prepare tablets with varying content of warfarin (2-10 mg) from acommon blend, which fulfil the pharmacopoeial requirements as well as the requirements of regulatory authorities for content uniformity.