In this study we used spectrophotometry to investigate the effect of negative concentrations of sodium chloride ions on photosynthetic pigments in Elodea canadensis (Michx. 1803). The concentrations of pigments, carotenoids, chlorophyll a and chlorophyll b, in plant leaves provide information about the physiological state of plants and were determined using a spectrophotometer. Quantity and dynamics analyses of photosynthetic pigments are effective methods which allow determining changes in metabolites of plant cells even at insignificant cellular damage. During this research photosynthetic pigments in leaves were obtained at the different sodium chloride levels: 0.0, 0.025, 0.05, 0.1, 0.5 and 1.0 M. The results of this research indicate that these types of stressors at high concentrations: 0.1, 0.5 and 1.0 M after a prolonged time of impact on plant leaves lead to a decrease of photosynthetic pigments and inhibit growth and development of a plant as a whole.

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Impact of moderate heat stress on the biochemical and physiological responses of the invasive waterweed Elodea canadensis (Michx.

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Salmonellosis infection is caused by bacteria of the genus Salmonella. There are many pathways for the pathogenic bacteria to spread which is through contaminated food, water, and contact with animals. The research was conducted to detect Salmonella spp. carriage in free-living aquatic turtles and zoo turtles. Turtles are frequent inhabitants of zoos and the owners of a large number of bacteria in their outer skin and shell surfaces that under adverse conditions can multiply and lead to the development of infection. However, they are known to be a frequent source of Salmonella infection without showing signs of disease. The risk of human infection exists if personal hygiene is not followed after contact with a turtle. Identification of bacteria of the genus Salmonella, the main causative agent of the disease was determined by the standard method on chromogenic Salmonella LAB-Agarᵀᴹ (BIOMAXIMA, Poland) agar. The inoculation was incubated under aerobic conditions at 37 ± 1°C for 72 h. Serotype (D serotype) was determined by serotyping in 11 from 16 (68.75%) Zoo inhabitants but not found in 25 free-living turtles. Our present research is of theoretical and practical value for the study of free-living turtles as well as from the collections of zoos under protection in Latvia and Europe. It is necessary to remember the possibility of infection with pathogenic bacteria.

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In the present study, different eggs were collected and analyzed from five various animal species: European pond turtle (Emys orbicularis (Linnaeus, 1758)), giant African land snail (Achatina fulica (Bowdich, 1822)), common ostrich (Struthio camelus (Linnaeus, 1758)), white, light-brown, and dark-brown laying hen (Gallus gallus domesticus (Linnaeus, 1758) and European quail (Coturnix coturnix (Linnaeus, 1758). The typical mineral shell mainly composed of the calcite polymorph of CaCO3 but the eggshell consists of membranes, that composed mainly of proteins. The shell quality also could be assigned by several external and internal factors such as oviposition time, animal genotype and age, housing system (for poultry), and mineral nutrition complex. The CaCO3 content was determined by the standard titration method, coz the titration could provide a reliable method for evaluation of CaCO3 content in different types of eggshells. The structural surface characterization of eggshells was performed by scanning electron microscopy (SEM) with a field emission gun. In terms of chemical composition, ostrich eggshells generally did not differ much from those of laying hen, turtles, giant snails, or quail eggs, but the concentration of calcium carbonate was the highest. The average calcium carbonate content of various eggshells is between 84 and 98%. The thickness of the eggshell ranges from 0.08 to 1.89 mm, and it  is not the same over the entire surface of the egg. At the sharp end of the egg, the shell is slightly thicker than at the blunt end. The purpose of this study was to study the quantitative content of calcium carbonate in various eggshells of different animals to draw further conclusions in which animals the eggshell contains the maximum amount of biological calcium carbonate.