Roost ectoparasites are believed to have a negative impact on fitness of their hosts as birds or mammals. Previous studies were mostly focussed on the synchronization between reproduction cycles of ectoparasites and hosts living in infested roosts. However, to date, it has not been examined how fast ectoparasites colonize new, non-infested roosts and thus increasing the impact on the local populations of hosts. The parasite-host model was studied, including bat bugs Cimex pipistrelli and soprano pipistrelles Pipistrellus pygmaeus, where bat behaviour was observed which tended to reduce the parasite load in bat roosts. We investigated (1) whether bats change their roosting behaviour when we discontinued synchronization of their reproduction and the life cycle of the bat bugs and (2) how fast and which stages of bat bugs reoccupy cleaned roosts. In a 3-year field experiment, we removed all bat bugs from six bat boxes in each spring. Pipistrelles bred young in all non-infested boxes during these 3 years. In addition, 8 years of regular observations before this experiment indicate that bats avoided breeding in the same bat boxes at all. Bat bugs were found again in clean boxes in mid-May. However, their densities did not maximise before the beginning of June, before parturition. A re-appearance of bugs was observed after 21-56 days after the first bat visit. Adult bugs, mainly females, colonised cleaned boxes first though at the same time there were a lot of younger and smaller instars in non-manipulated roosts in the vicinity.

Bat bugs are often roost ectoparasites of bats. Previous studies have shown that bats shifting roosts within the growing season prevent the massive reproduction of these parasites. We postulated that there could be other antiparasitic strategies of philopatric bats roosting in non-dwelling spacious roosts. Unfortunately, there are no studies devoted to such a topic. For 3 years, two attics highly and less infested by bat bugs (Cimex pipistrelli) with breeding females of Myotis myotis were monitored. From April, after the arrival of the bats, to November, abundance of all instars and adult bugs was sampled in the attics by adhesive traps. We found different patterns in the bug abundances and dynamics in the two attics. In highly infested attic, bat bugs induced pregnant females to move from the infested site of the attic to the non-infested one. Internal temperature and relative humidity were similar in both infested and non-infested sites. Females roosted in the infested site till time before parturition and then moved to the non-infested site within attic. When bats were absent in their old site, the abundance of nymphal instars of bugs decreased by half. Although adult bats can survive under high parasite loads of bat bugs, reproducing females prevent parasite reproduction and simultaneously reduce parasite load in the young by shifting inside spacious roosts.

X-ray diffraction is commonly used in the pharmaceutical industry to determine the atomic and molecular structure of crystals. However, it is costly, sometimes time-consuming, and it requires a considerable degree of expertise. Vibrational circular dichroism (VCD) spectroscopy overcomes these drawbacks while also being highly sensitive to small changes in conformation and molecular packing in the solid phase. Here, we investigate the ability of VCD to distinguish between different crystal forms of the same molecule (polymorphs) and, thereby, identify those with the greatest pharmaceutical potential. First, we developed a universal experimental approach for obtaining reliable and reproducible solid-phase VCD spectra. Using three amino acids (serine, alanine, tyrosine) and one hydroxy acid (tartaric acid) as model pharmaceutical ingredients we investigated an effect of various experimental conditions on resulting VCD spectra. Solid samples were prepared using two techniques: (i) suspension of each model compound in oil (mulling agent); (ii) mixture of the model compound and crystalline powder (matrix) compressed into a pellet. Additionally, to achieve artifact-free results with a maximal signal-to-noise ratio, the following experimental conditions were optimized: time of spectral acquisition (0.5‒3h), mulling agent (Nujol, fluorolube), pellet size (0.7 and 20 mm in diameter) and pellet matrix (KBr, KCl, CsI). Then, the optimized approach was successfully applied to distinguish three polymorphs of the antiviral drug sofosbuvir. Our results suggest that solid-state VCD represents a relatively rapid, cost-effective, and easy-to-use structural probe for the identification of crystal structures, with potential use in pharmaceutics.

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Jihočeská univerzita v Českých Budějovicích, Zdravotně sociální fakulta, katedra radiologie a toxikologie Summary Certain chlorinated propanols occur as contaminants in some foodstuffs, particularly in plant protein hydrolyzates. The most frequently occurring contaminant from this chemical group known as chloropropanol is 3-monochloropropane-1,2-diol (3-MCPD). Together with 1,3-dichloropropanol (1,3-DCP), it was identified as a substance produced in the manufacture of spicy admixtures through the acid hydrolysis of plant proteins. 3-MCPD is a contaminant encountered in the course of the meal preparation and it was first found in different spices, such as plant protein hydrolyzates and soya or oyster sauce. 3-MCPD and 1,3-DCP can also be produced in foodstuffs as a result of heat effects (for example when baking cereal products) similarly as in the course of the food preparation and storage, but the accurate mechanism of their production is still unknown. Chloropropanols are produced in foodstuffs simultaneously containing fat and salt, if they are exposed to high temperature in the course of cooking. Studies are aimed at 3-MCPD, which induces infertility in rats, inhibits immunity reactions and is likely to be carcinogenic. In 2001, the Scientific Committee for Foodstuffs established the tolerable daily intake of 3-MCPD as 2 mg/kg (per kg body weight) and anchored in legal EU regulations of 3-MCPD concentrations of 20 mg/kg for food prepared from hydrolyzed plant proteins and for the soya sauce. In 2007, 3-MCPD-esters of fatty acids (3-MCPD esters) were first found in a number of foodstuffs including refined edible fats, such as margarine and oils but also in products for suckling babies and in the human milk. In spite of the fact that there are a number of toxicological studies performed in animals, little is known about the mechanism of the 3-MCPD ester production, their bioavailability, toxicological kinetics, toxicological dynamics and toxicity. The article presented here deals with possible risks of 3-MCPD and 1,3-DCP to human health.