Biopolymer matrix systems for incorporation of biologically active substances

S. Dyankova, A. Solak
Abstract. A number of biopolymers have a potential to be used as a basis for producing films, coatings and therapeutic systems with application in medicine, pharmacy and food industry. The objective of the present work was to obtain monopolymer and composite matrices which can be used as carriers of biologically active substances. Protein (collagen, gelatin, soy protein) and polysaccharide (sodium alginate, highmethoxyl pectin, carrageenan and carboxymethylcellulose) hydrocolloids were investigated and a method for producing monopolymer and composite films was developed. The obtained materials were characterized by their physicochemical and mechanical properties; their behavior at different pH values and in media simulating the conditions in the gastrointestinal tract. The protein films showed lower moisture content and absorbed less water compared to the polysaccharide films. It was found that films prepared from collagen dispersions were the most resistant at different pH and in simulated gastric and intestinal juice. The polysaccharide films dissolved under the studied conditions except for the alginates which kept their wholeness in acidic medium and in simulated gastric juice, but degraded in intestinal juice. The combination of two biopolymers – protein-polysaccharide or polysaccharide-polysaccharide improved considerably the mechanical properties of the films. All composite films also showed significant differences in the dissolution profile compared to the individual biopolymer films.

odbutton

Ecological assessment of the phytoplankton community in the Bulgarian Black Sea coastal waters

D. Petrova, G. Kostadinova, D. Gerdzhikov
Abstract. The purpose of this article was to study and make an ecological assessment of the phytoplankton community in the Bulgarian Black Sea coastal waters for the period 2008 – 2010. Taxonomic distribution in the phytoplankton community is traced and analyzed on the basis of 389 quantitative and qualitative seawater samples. Dominant and subdominant phytoplankton species, qualitative and quantitative monthly and seasonal dynamics of the main groups in phytoplankton have been identified as well as their importance for the ecological status of the Black Sea ecosystem. The obtained results for phytoplankton demonstrated a comparative reduction of the trophic degree of the Bulgarian coastal waters, dominating natural factors of the environment over the anthropogenic ones and the present status of “good” and “very good” of the researched coastal area, according to the explored parameters. The phytoplankton annual development is accordingly with the climatic conditions. Also three seasonal phytoplankton successions were defined throughout the year.

odbutton

Contemporary assessment of the development of the genus Chaetoceros in the Bulgarian coastal waters

D. Petrova, D. Gerdzhikov, G. Kostadinova
Abstract. The genus Chaetoceros Ehrenberg of class Bacillariophyceae is widespread and abundant in species in the Black Sea phytoplankton. The aim of the article was to study its distribution in water and to analyzed its contemporary involvement in the formation of qualitative and quantitative composition of phytoplankton, the season dynamics of genus during the hydro-biological year and its role in the ecology of the Bulgarian Black Sea coastal water area for the period 2008 – 2010. It was found out that the highest species diversity, abundance and biomass of the genus were in the autumn and spring – a bimodal pattern of annual growth. 20 species and forms were registered of the genus Chaetoceros. They formed up to 1/3 of the taxonomic composition of Diatoms and 1/10 of all phytoplankton species. “Blooms” of representatives of the genus Chaetoceros in the researched period were not registered.

odbutton

Possible adverse effects of tetracyclines on the human health and the environment

Y. Koleva, T. Dimova, G. Angelova
Abstract. Medicines have an important role in the treatment and prevention of disease in both humans and animals. But it is because of the very nature of medicines that they may also have unintended effects on animals and microorganisms in the environment. Although the side effects on human and animal health are usually investigated in thorough safety and toxicology studies, the potential environmental impacts of the manufacture and use of medicines are less well understood and have only recently become a topic of research interest. This is further complicated by the fact that some pharmaceuticals can cast effects on bacteria and animals well below the concentrations that are usually used in safety and efficacy tests. In addition, breakdown products and the combination of different biologically active compounds may have unanticipated effects on the environment. Although it may be safe to assume that these substances do not substantially harm humans, we have only recently begun to research whether and how they affect a wide range of organisms in the environment and what this means for environmental health. The aim of this work is to predict the possible adverse effects of some tetracyclines on the human health and the environment. Persistent, bioaccumulative, acute and chronic toxic were predicted for ten tetracyclines by baseline models and a software of PBT Profiler. Possible metabolic activation (observed and predicted) of some tetracyclines was applied by a software of (Q)SAR Application Toolbox. Results show that some of them are persistent, do not bioaccumalate in the food chain and are with moderate to low toxicity. The tetracyclines were metabolically activated in the liver and their protein and DNA binding was estimated. Observed metabolic pathways weren’t observed. Predicted metabolites have different mechanisms of protein and DNA binding.

odbutton

Development and characteristics of accessions of Eragrostis tef (Zucc.) Trotter in the South Dobrudja

H. Stoyanov
Abstract. Abyssinian teff (Eragrostis tef) is a subtropical cereal and forage crop grown primarily in Ethiopia, Eritrea and South Africa, and limited in the southern United States of America. Demand for alternative crops to diversify grain production puts this crop as potentially more promising for areas with arid climate and possible heavy summer rainfall such as South Dobrudja. To determine the suitability of Abyssinian teff under the conditions of South Dobrudja three samples of the crop were studied. Productive and maximum tillering, formed panicle length, panicle fertility of the whole and its parts, depending on the period and conditions during the flowering are observed. The weight of seeds per panicle, weight of 1000 seeds and the yield are determined. Under the specific environmental conditions only one of the studied accessions successfully reached the above mentioned average yield of the crop (1650kg/ha), despite the little precipitation during vegetation – 295 mm. Its productive tillering is high – 6-8-10 (3-4 productive tillers per plant for other accessions). The length of panicle averaged 43 cm, and the number of individual branches was between 25 and 30. The weight of seeds in the panicle averaged approximately 1g, and the weight of 1000 seeds averaged 0.36g, which is above average for the crop. High yield potential of Abyssinian teff was negatively influenced by a combination of heavy rainfall with winds which leads to strong plant lodging. The average fertility of the panicle is 71%, varying between 23 to 88% and fertility decreases upward to the top of the panicle. Flowering starts from the top downward to the base of the panicle, and this determines the negative impact of environmental factors in early flowering. The average number of florets in the spikelet is 4 and the average number of spikelets in the panicle is 1000. A large number of spikelets with more fertile florets are formed in the middle of the panicle. In the other two accessions panicles are small, loose, with few spikelets and low fertility. Despite some of its negative properties Abyssinian teff emerged as a promising crop, which requires exhaustive studies of its suitability to the conditions of the country.

odbutton

New data for Leucoagaricus and Leucocoprinus (Agaricaceae) in Bulgaria

M. Lacheva
Abstract. New data on seven lepiotaceous fungi are reported for the country. One of them – Leucocoprinus badhamii (Berk. and Broome) Locq. were recorded for the first time in Bulgaria. The species Leucoagaricus wichanskyi (Pilát) Bon and Boiffard are of conservation value included in the Red List of fungi in Bulgaria. All taxa are presented with brief chorological data and notes on their distribution in the country. The new species are described and illustrated by photographs. Presented are macroscopic pictures of some of the typical species. Some observations are discussed in support of the microscopic separation of Leucocoprinus badhamii from Leucoagaricus pilatianus. The aim of the paper is to enrich the information about fungal diversity of Bulgarian mycota.

odbutton

Botanical composition of the main pasture types in Sakar and Strandja region

V. Vateva, K. Stoeva, D. Pavlov
Abstract. Natural meadows and pastures are some of the most valuable ecosystems, which oversee a wide variety of plant species. Exploration of the biodiversity of the pasture swards and meadows in the region is mainly to familiarize and with a view to their protection and conservation. Evaluation of the botanical composition of meadows and pasture swards is important for establishing the dominated groups, their variability and relation to productivity and biomass quality. The aim of present study is to analyse the changes in the botanical composition of the main grassland types in areas of Sakar and Strandja, to make comparative environmental assessment of changes occurring in the botanical composition of pasture swards in the two similar regions. The observations demonstrate that the main types of grassland swards in Sakar and Strandja are cereal-forbs. In the area of Strandja they occupy a greater proportion compared to the pastures of Sakar. In Sakar participation of leguminous species is greater than that of the Strandja mountain. From cereal species the most dominant are the species from the genera Festuca, Bromus, Andropogon, Agrostis, Cynodon Lolium. In the leguminous species dominate representatives of Trifolium and Lotus. In the group of forbs the greatest is the participation of the genera Achillea, Hypericum, Plantago, Centaurea, Convolvulus.

odbutton

Soil properties and salt content of soil from Inland salt meadow near Radnevo town

M. Todorova, N. Grozeva, D. Dermendgieva
Abstract. One of the most representative localities of Inland salt meadows in the country is the Inland salt meadow near the town of Radnevo, Bulgaria. A soil unit of that salt meadow has not been a subject of any detailed study. The objective of the present paper is to study the properties, degree and type of salt content of the soil from Inland soil meadow. The survey was conducted in 2011 – 2012. For the purpose of the study in July 2011 a soil profile was made with a depth of 100 cm on a relatively dry, not waterlogged and centrally located study territory. Samples from the soil profile were taken from different depth: 0-10 cm, 10–20 cm, 20–30 cm, 30–40 cm, 40–50 cm, 50–60 cm, 60–70 cm and 70–80 cm. A total of 60 soil samples were also taken from the study territory from a depth of 0–20 cm in same period. Soil samples were analysed for electrical conductivity, pH, Cl -, HCO- and SO2- content. The main reasons leading to swamping and 3 4 soil salinization are the accumulation relief with non-draining plane and micro depressions in it, the poor drainage of underground filtration water, high level of groundwater and high content of clay in the soil which results in low permeability. The soil unit is Gleic Vertisol, surface waterlogged, saline of sulphate–chloride type.

odbutton

Influence of Herbagreen mineral fertilizer on seed production of cucumber, melon and zucchini

N. Velkov, V. Petkova
Abstract. The effect of Herbagreen mineral fertilizer on seed production of cucumber, melon and zucchini was evaluated. Three times treatment with the fertilizer at a dose of 0.04% at an interval of 14 days has a positive effect on seed yield in the studied cultures. Proven high effect was established in the indicator number of fruit per plant. There were no significant differences between treated and untreated (control) variants at the indicators: number of seeds per fruit, number of seeds per gram, weight of seeds per fruit (g), number of seeds per gram; absolute mass of seeds (g). Increasing the yield of the seed does not have any negative effect on the quality of the seeds. By the worked out regression equations the effect of application of Herbagreen could be foreseen.

odbutton

Analysis of energy consumption for artificial lighting of rooms for fattening of pigs

V. Katsarov, K. Peychev
Abstract. State aid for the implementation of voluntary commitments for human attitude toward pigs involves providing artificial light for 11 hours a day. This technological approach is associated with a further increase of energy consumption at farms. Therefore, relevant calculation methods for determination of the energy costs of providing artificial illumination by various types of lighting fixtures are proposed. This comparative analysis can be used by farmers to optimize the energy consumption in different categories of pigs.

odbutton