25 research outputs found
Environmental Genomics as a source for the isolation of new operons and gene clusters from microbial consortia
No full textZentraler Aspekt dieser Arbeit war die Isolierung von neuartigen Biotinbiosyntheseoperons aus mikrobiellen Konsortien mit Hilfe kombinierter Anreicherung und direktem Klonieren. Hierzu wurden Cosmid-Genbanken aus Anreicherungskulturen mit einer Fragment-Größe von ca. 30 kb angelegt. Anschließend wurden die Genbanken auf Klone durchmustert, die möglicherweise Biotinbiosyntheseoperons (bio-Operons) tragen. Dabei wurden mit Hilfe funktionaler Komplementation sechs Cosmid-Klone identifiziert, die signifikante Mengen an Biotin produzierten. DNA-Sequenzanalysen der Cosmidklone zeigten, dass in allen Fällen vollständige bio-Operons vorhanden waren und die Sequenzanalysen identifizierten eine Reihe weiterer neuer Gene. Die Biotinproduktion der positiven Klone lag in einem Bereich von einigen pg/ml bis zu 3 800 pg/ml in definierten Medium. Aufgrund der sehr hohen Syntheseleistung wurde der Cosmid-Klon pCosHE2 für die Konstruktion von Biotin-überproduzierenden Mikroorganismen ausgewählt und das drauf enthaltende bio-Operon in verschiedene Vektoren kloniert. Diese bio-Konstrukte wurden in Bakterien aus neun verschiedenen Gattungen mobilisiert und anschleißend deren Biotinproduktionsfähigkeiten auf Mineralmedium getestet. Als Wirte für die Expression von Umwelt-isolierten bio-Genen wurden dabei Corynebacterium glutamicum, Sinorhizobium meliloti, Rhizobium NGR234, Rhizobium etli, Ralstonia eutropha, Agrobacterium tumeafciens, Klebsiella planticola, Escherichia coli und Xanthomonas campestris gewählt. Interessanterweise, nur E. coli-Stämme die das bio-Operon aus dem pCosHE2 überexprimierten, zeigten eine sehr hohe Biotinkonzentration (> 0,2 mg/l) im Kulturüberstan, wobei bis zu 3,5 mg/l Biotin gemessen wurden. Weitere Arbeiten konzentrierten sich auf die Analyse regulatorischer Phänomene bei Biotinsynthese und Aufnahme. Mit Hilfe von 2D-Gelelektrophorese wurden einige Proteine identifiziert, die in Zusammenhang mit dem Biotin-regulatorischen Netzwerk in gram-negativen Bakterien stehen.The main goal of the present work was the isolation of biotin biosynthesis genes and operons from microbial consortia employing a combined enrichment and direct cloning strategy. Cosmid libraries with large inserts of DNA (>30 kb) were constructed from enrichment cultures, which had been inoculated with different environmental samples. The cosmid libraries were screened for clones containing complete biotin biosynthesis operons (bio-operons) by functional complementation in E. coli. Altogether, six cosmid clones were identified that produced significant amounts of biotin. Sequence analysis of the complete cosmid clones identified six bio-operons and many other novel genes. Biotin synthesis rates of the tested clones were highly variable and ranged from just a few pg/ml to 3,800 pg/ml in defined medium. Because the clone designated pCosHE2 showed the highest biotin biosynthesis rates the corresponding bio-operon was subcloned into different vectors and the constructs were transferred into bacteria from nine different genera to test the potency for commercial biotin production. Hosts for the expression of the environmentally derived bio-genes included Corynebacterium glutamicum, Sinorhizobium meliloti, Rhizobium sp. NGR234, Rhizobium etli, Ralstonia eutropha, Agrobacterium tumeafciens, Klebsiella planticola, Escherichia coli and Xanthomonas campestris. Surprisingly, significant amounts of biotin (> 0.2 mg/l) were synthesized only in E. coli carrying extra copies of the pCosHE2 derived bio-operon. Up to 3.5 mg/l biotin were found in culture supernatant of recombinant E. coli strains grown on defined media in batch cultures. Additional studies focused on regulatory aspects linked to biotin biosynthesis and biotin uptake in gram-negative bacteria. For this purpose 2-dimensional gel electrophoresis was employed and this work has led to the identification of several proteins involved in the biotin-regulatory network
Direct Cloning from Enrichment Cultures, a Reliable Strategy for Isolation of Complete Operons and Genes from Microbial Consortia
No full textABSTRACT
Enrichment cultures of microbial consortia enable the diverse metabolic and catabolic activities of these populations to be studied on a molecular level and to be explored as potential sources for biotechnology processes. We have used a combined approach of enrichment culture and direct cloning to construct cosmid libraries with large (>30-kb) inserts from microbial consortia. Enrichment cultures were inoculated with samples from five environments, and high amounts of avidin were added to the cultures to favor growth of biotin-producing microbes. DNA was extracted from three of these enrichment cultures and used to construct cosmid libraries; each library consisted of between 6,000 and 35,000 clones, with an average insert size of 30 to 40 kb. The inserts contained a diverse population of genomic DNA fragments isolated from the consortia organisms. These three libraries were used to complement the
Escherichia coli
biotin auxotrophic strain ATCC 33767 Δ(
bio-uvrB
). Initial screens resulted in the isolation of seven different complementing cosmid clones, carrying biotin biosynthesis operons. Biotin biosynthesis capabilities and growth under defined conditions of four of these clones were studied. Biotin measured in the different culture supernatants ranged from 42 to 3,800 pg/ml/optical density unit. Sequencing the identified biotin synthesis genes revealed high similarities to
bio
operons from gram-negative bacteria. In addition, random sequencing identified other interesting open reading frames, as well as two operons, the histidine utilization operon (
hut
), and the cluster of genes involved in biosynthesis of molybdopterin cofactors in bacteria (
moaABCDE
).
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Geological – Geomorphological Features of River Catchments in Flood Susceptibility Assessment (on the Example of Middle Struma Valley, Bulgaria)
No full textInternational audienceThe geological-geomorphological features of the river catchments control flood propagation by influencing the surface runoff and its redistribution to surface and underground flow. The paper analyses the geological-geomorphological susceptibility to floods in a part of the river Struma valley – Municipalities Kresna and Strumyani (Bulgaria, EU). The following parameters are considered: lithology (presented by water permeability, capacity and type of rock reservoirs), distance from streams/river, slopes and fluvial landforms. Raster layers for each one of these parameters are created in geographic information system (GIS) environment and susceptibility rates are assigned. The flood susceptibility map is elaborated by spatial weighted sum overlay of the raster layers. The results show that the susceptibility is the highest in the low part of the valley, south of Kresna. The susceptibility of flooding is not equal over the whole area of the floodplain but depends on the retention capacity of the alluvial deposits and the hydro-geomorphological state of the floodplain. The river bank height above the water level and the river bed type are also taken into consideration by application of fuzzy logic. Using the fuzzy logic minimizes some imperfections of the initial data and gives good results in data-scarce areas. The fuzzy logic model is designed as a two-level hierarchical system with three inputs and one output. The output gives the complex assessment for geological-geomorphological flood susceptibility of study area regarding the interaction of the three inputs. The results of the current research aims to direct the attention of planning experts and decision-makers to the importance of geological-geomorphological parameters in flood management and can be considered as a first step of flood hazard assessment
Geoinformation Approach in Soil Erosion Susceptibility Assessment – A Tool for Decision Making: Case Study of the North-Western Bulgaria
No full textInternational audienceThe soil erosion is considered as one of the most serious environmental problem in a global scale. The development of the process could have negative impact on water, vegetation and ecosystem as a hole, as well as to influence on the quality of life. If the process is not mitigated in long term it could change the topographic surface and to trigger geomorphological hazards. The researches on soil erosion require analyses of large volume of information about soil properties, topographic surface, precipitation and land use. In the current research GIS technology is used for building the data base, spatial analyses and visualization of the results. The Universal Soil Loss Equation (USLE) is applied in Map Algebra and spatial distribution of soil loss is presented. The results are considered in relation to land use, particularly arable lands and vineyards. The application of computer technology provide opportunities for easy processing of data and updating the model by adding new data which can be used by territorial planning experts, local authorities and farmers in the planning process, monitoring and mitigating the soil erosion
Гъвкавост на пазара на труда в България
No full textГъвкавостта на трудовия пазар е от изключително значение за неговото ефективно функциониране, особено предвид целите и приоритетите, основани на Европейската стратегия по заетостта. Изследването прави преглед на съществуващата законова и институционална уредба на българския трудов пазар, въз основа на който се преценява дали и доколко е гъвкав трудовият пазар в България. Използваният метод е анализ в ретроспекция, както и сравнителен анализ със законодателствата на страни-членки на ЕС. След прегледа на условията, в които българският трудов пазар функционира, е анализирано доколко участниците на пазара на труда реално се възползват от тях, за да бъдат гъвкави. Накрая са представени факторите, които според авторите ограничават гъвкавостта на пазара на труда в България.гъвкавост на пазара на труда; наемане на работници; прекратяване на трудовите отношения; работно време; работна заплата; мобилност на работната сила; териториална мобилност
AGING GRACEFULLY IN OSTEOARTHRITIS: IMPACT OF COMORBIDITIES
Full text linkBackground: Osteoarthritis (OA) is a prevalent musculoskeletal disorder, often complicated by comorbid conditions such as cardiovascular diseases, metabolic syndromes, and mental health issues. These comorbidities significantly impact the progression of OA and the effectiveness of its management, posing challenges for comprehensive patient care.
Objectives: This review examines the relationship between OA and its common comorbidities, focusing on cardiovascular diseases, metabolic conditions, and mood disorders. We also explore the impact of pharmacological and non-pharmacological treatments in these patients, emphasizing the importance of integrated care strategies.
Methods: Data from multiple studies were analyzed to assess the association between OA and comorbid conditions. The studies examined mortality risk, cardiovascular incidents, metabolic syndrome, diabetes, obesity, and mood disorders, while considering the effects of various OA treatment modalities, particularly non-steroidal anti-inflammatory drugs (NSAIDs).
Results: Cardiovascular comorbidities, including coronary heart disease, are significantly linked to OA, with functional limitations such as impaired mobility being major contributors to increased cardiovascular risks and mortality. NSAIDs, commonly prescribed for OA, present substantial cardiovascular and renal risks, complicating their use in patients with pre-existing cardiovascular conditions. Metabolic comorbidities, particularly obesity and diabetes, are highly prevalent in OA patients and are associated with reduced quality of life and exacerbation of OA symptoms. Furthermore, mood disorders like depression and anxiety are common among OA patients, leading to a vicious cycle of pain and psychological distress that worsens functional outcomes.
Conclusions: OA is closely related to various comorbidities, necessitating a holistic, multimodal approach to treatment. Beyond pharmacologic interventions, lifestyle changes, psychosocial support, and careful management of comorbid conditions are essential for improving outcomes in OA patients
Pharmacokinetics and safety of paclitaxel delivery into porcine airway walls by a new endobronchial drug delivery catheter
No full textInternationalizing Campus Partners
No full textThe available discourse on how international students’ needs and
expectations are accommodated in U.S. higher education institutions is
extensive while the corresponding research on how International Services’
Staff (ISS) are prepared for the challenge is limited. The purpose of this
essay was to research the personal, academic, and professional background
of individuals working in International Services Offices (ISOs) nationwide
and identify issues that are not sufficiently addressed. The survey allowed
for the collection of data on the training and experience of International
Services Staff as well as the methods and strategies used to effectively
communicate with international students. Upon discussion of the findings
and their significance, the author proposes future recommendations through
the implementation of a practical training module.ISSN: 2162-3104 Print/ ISSN: 2166-3750 Online
Volume 7, Issue 3 (2017), pp. 876-892
© Journal of International Students
http://jistudents.org
Crafting Urban Landscapes and Monumental Infrastructure: Archaeometric Investigations of White Marble Architectural Elements from Roman Philippopolis (Bulgaria)
No full textThis study explores the provenance of white marble architectural elements from Roman Philippopolis, with a particular focus on the Eastern Gate complex. By determining the origin of the marble, we aim to elucidate economic, social, and urban dynamics related to material selection and trade networks. The investigation examines the symbolic significance of prestigious marble in elite representation and highlights the role of quarry exploitation in the region’s economic and technological development. The Eastern Gate, a monumental ensemble integrated into the city’s urban fabric, was primarily constructed with local Rhodope marble, alongside imported materials such as Prokonnesian marble. Analytical methods included petrographic examination, chemical analysis of trace elements (Mn, Mg, Fe, Sr, Y, V, Cd, La, Ce, Yb, and U), and stable isotope analysis (δ18O, δ13C). Statistical evaluations were performed for each sample (37 in total) and compared with a comprehensive database of ancient quarry sources. The results underscore the dominance of local materials while also indicating selective use of imports, potentially linked to symbolic or functional criteria. The findings support the hypothesis of local workshop activity in the Asenovgrad/Philippopolis area and shed light on regional and long-distance marble trade during the Roman Imperial period, reflecting broader economic and cultural interconnections
