DSpace 7
DSpace is the world leading open source repository platform that enables organisations to:
- easily ingest documents, audio, video, datasets and their corresponding Dublin Core metadata
- open up this content to local and global audiences, thanks to the OAI-PMH interface and Google Scholar optimizations
- issue permanent urls and trustworthy identifiers, including optional integrations with handle.net and DataCite DOI
Join an international community of leading institutions using DSpace.
The test user accounts below have their password set to the name of this software in lowercase.
- Demo Site Administrator = dspacedemo+admin@gmail.com
- Demo Community Administrator = dspacedemo+commadmin@gmail.com
- Demo Collection Administrator = dspacedemo+colladmin@gmail.com
- Demo Submitter = dspacedemo+submit@gmail.com
Recent Submissions
Influence of in vitro cultivation factors on micropropagation and alkaloid determination of Convolvulus persicus L.
(Plovdiv University Press "Paisii Hilendarski", 2026-01-25) Doycheva, Iva; Doncheva, Tsvetelina; Philipov, Stefan
Convolvulus persicus L. is a critically endangered species native to Bulgaria. Studying the conditions for its in vitro cultivation is important for its ex-situ conservation. A number of factors influence the growth, development, and multiplication of in vitro plants. In this study, the effects of several medium components - including the type of gelling agent, the quantity of macrosalts, activated charcoal supplementation, and plant growth regulators - were investigated to determine the most suitable conditions for the in vitro cultivation of the species. The effects of explant type and culture vessels were also examined. The type of gelling agent (Gelrite) and the explant significantly affected culture growth. Culture vessels and plant growth regulators had a smaller influence, while the effect of activated charcoal depended on its combination with the other factors. The quantity of macrosalts did not influence plant growth in vitro. A phytochemical analysis of the alkaloid content of Convolvulus persicus was conducted for the first time. The phytochemical analysis revealed that three alkaloids - nicotine, tropinone, and Nmethylpyrrolidinyl-cuscohygrine - were biosynthesized by C. persicus at two developmental stages. Nicotine was identified as the major alkaloid in the species.
Influence of the urban environment on the metabolic activity and functional diversity of phyllospheric microbial communities in linden trees
(Plovdiv University Press "Paisii Hilendarski", 2026-01-25) Dimitrova, Katya; Spasov, Spas; Bogdanov, Nikolov; Shilev, Stefan; Petrova, Slaveya
It has been shown that microorganisms associated with the crown of trees (phyllosphere) can improve their ability to purify the air from pollutants. On the one hand, this is due to the metabolites released by the microorganisms that stimulate the development of trees and their resistance to stress, and on the other hand, the microorganisms themselves also are able to degrade some of the atmospheric pollutants. The aim of the present study was to assess the influence of the urban environment on the metabolic activity and functional diversity of microbial communities in the phyllosphere of linden trees, planted in four experimental plots within the city of Plovdiv (Bulgaria). Each plot is characterized by different anthropogenic load, thus allowing for detection of potential specificity of microbial metabolism. A total of 12 saplings of Tilia tomentosa Moench were planted (3 individuals per plot) and leaf samples were collected after 3-month period in the urban environment. Biolog EcoPlate™ of the BIOLOG system (Biolog, Hayward, CA, USA) was used for estimation of metabolic activity of microbial communities, associated with linden trees. The epiphytic communities isolated from leaf samples of Plot 4 (lowest degree of urbanization) showed the highest average-well color development (AWCD) and substrates` metabolic activity. It was found that microorganisms in the two more strongly affected by the traffic locations (Plot 1 and Plot 3) have a higher rate of carbohydrate assimilation and a lower rate of phenolic compounds assimilation compared to the other two locations. Most of the analyzed functional indices showed higher biodiversity and better distribution of substrate utilization in the epiphytic microflora of the leaves of trees planted on Plot 4 (lowest urbanization intensity).
Breeding density and habitat preferences of the European Turtle Dove Streptopelia turtur Linnaeus, 1758 (Columbiformes: Columbidae) in Bulgaria: preliminary results
(Plovdiv University Press "Paisii Hilendarski", 2026-01-15) Gruychev, Gradimir; Stoyanov, Stoyan; Angelov, Evlogi; Mihaylov, Hristo
We conducted country-wide surveys from 15 May to 31 July 2022 to quantify singing males’ population size and habitat-specific density of Turtle Dove (Streptopelia turtur). We applied point counts at survey stations situated in 11 plot locations systematically distributed across the country. The average Turtle Dove’s density was estimated as 10.1 singing birds per 1 km2 (λ = 10.084, SE = 0.674, 95% CI: 8.846 – 11.496). The mean detection probability (p) was 0.115 (95% CI: 0.105 – 0.126), and the scale parameter of half-normal detection function was 120 m (σ = 119.74 m, SE = 3.53, 95% CI: 113.03 – 126.86). The effective radius was 169.33 m (95% CI: 159.84 – 179.37). The Turtle Dove densities were influenced by altitude with lower densities in higher elevations. The number of singing males increased from May to July. The abundance was influenced by habitat type and land cover, and it was positively correlated with tree height and shrub height measured around sampling points. The highest densities were recorded around stubbles, sunflower crops, and in a mixture of agricultural land cover, although their importance was insignificant. The density of singing males was higher in open areas, in oak and mixed deciduous forests, and in Paliurus communities as well.
Prevalence of opportunistic pathogenic Gram-negative bacteria from the Enterobacteriaceae family in the cloacal microflora of Testudo graeca and Testudo hermanni – a pilot study
(Plovdiv University Press "Paisii Hilendarski", 2025-12-08) Popova, Steliyana; Lazarkevich, Irina; Engibarov, Stephan; Mitova, Simona; Lalovska, Iva
Reptiles can harbour a variety of zoonotic bacteria in their gut, often asymptomatically. In this study, we report our preliminary data on the occurrence of opportunistic pathogenic Gram-negative bacteria in the cloacal microbiota of tortoises housed in the Rescue, Rehabilitation and Breeding Center in Banya village, Burgas District. A total of 24 healthy adult individuals were sampled: 12 spur-thighed tortoises (Testudo graeca) and 12 Hermann’s tortoises (Testudo hermanni), with equal numbers of each gender. Representatives of 7 genera from Enterobacteriaceae family, known as causative agents of rare but serious infections both in humans and animals, have been identified. The most common bacteria were Klebsiella spp., Salmonella enterica, Citrobacter braakii and Enterobacter cloacae, detected in over 75% of the individuals sampled. Morganella morganii, Pantoaea agglomerans and Escherichia coli were found less frequently, in 20% - 30% of individuals. No significant difference in bacterial load between tortoise species or between sexes was found. The high prevalence of opportunistic pathogens that tortoises host may pose a potential health risk, so strict hygiene practices are recommended when handling animals.
Ecological risk assessment of heavy metals and microbiological diversity of soil samples from some automobile workshops in Benin City, Nigeria
(Plovdiv University Press “Paisii Hilendarski”, 2026-01-07) Enerijiofi, Kingsley; Osariyekemwen, Nathaniel
The indiscriminate discharge of waste engine oil arising from auto-mechanic workshops is known to cause environmental challenges. This study investigated the pollution status of heavy metals and microbiological diversity of waste engine oil contaminated soils in Benin City. Standard laboratory methods were used in the study. The physicochemical parameters recorded were sandy loam, pH (6.8 - 7.9), EC (1.9 - 5.4 uS/cm), sulphate (42.51 - 68.45 mg/kg), Nitrate (1.08-2.10mg/kg), Phosphate (2.60- 4.92 mg/kg), Calcium (0.32 -0.64mg/kg), Magnesium (0.17- 0.28mg/kg), Sodium (0.11- 0.14 mg/kg) Potassium (0.10-0.18mg/kg), Zinc (31.92- 68.40mg/kg), Copper (9.21-13.65mg/kg), Chromium (0.23 -0.40mg/kg), Lead (2.40 - 6.20mg/kg), Manganese (32.92-51.70mg/kg), Iron (826.24 — 1012.4mg/kg), Nickel (2.11 — 3.10mg/kg) and Cadmium (1.98-3.10mg/kg). The total heterotrophic bacterial counts of soils samples from location A had the highest, 8.61x10^4cfu/g while location E had the least, 1.12x10^4cfu/g. location B had the highest fungal count, 8.04x10^3cfu/g while location C had the least, 1.11x10^3cfu/g. The bacterial and fungi isolated were Bacillus, Pseudomonas, Micrococcus, Clostridium, Corynebacterium, Penicillium, Fusarium, Aspergillus, Trichoderma and Geotrichum species. The pollution indices indicated iron had the highest contamination factor of 8.88 while Chromium had the least of 0.87. The geo-accumulation index showed that cadmium had the highest of 0.76 while iron had the least. The Quantification of concentration revealed that chromium had the highest of 90.32 while nickel had the least of 57.25. The waste engine oil polluted soil revealed unpolluted to moderately polluted status. This study recommends proper disposal of waste engine oil thereby safeguarding the environment and public health of citizens.