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  1. Article ; Online: Length-weight relationship of European catfish (Silurus glanis L.) fry reared at different stocking densities under controlled conditions

    V. Krasteva / M. Yankova

    Agricultural Science and Technology, Vol 13, Iss 1, Pp 47-

    2021  Volume 51

    Abstract: Abstract. The present paper investigates the body length and weight, and the size-weight variations of one-month-old European catfish reared at 4 variants of stocking density: Variant 1 – 5 spec/l; Variant 2 – 10 spec/l; Variant 3 – 15 spec/l and Variant ...

    Abstract Abstract. The present paper investigates the body length and weight, and the size-weight variations of one-month-old European catfish reared at 4 variants of stocking density: Variant 1 – 5 spec/l; Variant 2 – 10 spec/l; Variant 3 – 15 spec/l and Variant 4 – 28 spec/l. The experiment is carried out at the Institute of Fisheries and Aquaculture, Plovdiv for a period of 16 days, using a production system consisting of tubs with continuous water flow (0.7 l/min). At the end of the experiment, the fish from each variant are sorted in three size-weight groups: A – large, B – medium and C – small. The number of fish in each group is established. From the group of the medium- and small-sized fish, 150 speciments are measured, while from the group of the large specimens, which are the smallest in number, all specimens are measured for the biometric parameters body weight (BW, g) and total body length (TL, cm). The results from the study show small variations in the length and weight of the fish reared at the lowest stocking density (Variant 1). As the density increase, the size-weight differences between the specimens from Group A also increased, while of those from Group B they decrease. The number of the medium-sized fish decrease (p≤0.001) while the number of large specimens (p≤0.01) and small fish increase (p≤0.001).
    Keywords body length ; body weight ; density ; size ; specimens ; variations ; Agriculture ; S
    Subject code 590
    Language English
    Publishing date 2021-03-01T00:00:00Z
    Publisher Trakia University. Faculty of Agriculture, Stara Zagora
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: A Highly Water-Soluble and Solid State Emissive 1,8-Naphthalimide as a Fluorescent PET Probe for Determination of pHs, Acid/Base Vapors, and Water Content in Organic Solvents

    Nikolai I. Georgiev / Paoleta V. Krasteva / Ventsislav V. Bakov / Vladimir B. Bojinov

    Molecules, Vol 27, Iss 4229, p

    2022  Volume 4229

    Abstract: A new highly water-soluble 1,8-naphthalimide fluorophore designed on the “ fluorophore-spacer-receptor 1 -receptor 2 ” model has been synthesized. Due to the unusually high solubility in water, the novel compound proved to be a selective PET-based probe ... ...

    Abstract A new highly water-soluble 1,8-naphthalimide fluorophore designed on the “ fluorophore-spacer-receptor 1 -receptor 2 ” model has been synthesized. Due to the unusually high solubility in water, the novel compound proved to be a selective PET-based probe for the determination of pHs in aqueous solutions and rapid detection of water content in organic solvents. Based on the pH dependence of the probe and its high water solubility, the INH logic gate was achieved using NaOH and water as chemical inputs, where NaOH is the disabler and the water is an enabler. In addition, the probe showed effective fluorescence “ off-on ” reversibility on glass support after exposure to acid and base vapors, which defines it as a promising platform for rapid detection of acid/base vapors in the solid-state, thus extending the molecular sensing concept from solution to the solid support.
    Keywords 1,8-naphthalimide fluorescent probe ; solid state emission ; photoinduced electron transfer (PET) ; INH logic gate ; acid-base vapors ; water content ; Organic chemistry ; QD241-441
    Subject code 540
    Language English
    Publishing date 2022-06-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Application of rosemary essential oil (Rosmarinus officinalis Linnaeus, 1753) for anesthesia and transport of bighead carp (Hypophthalmichthys nobilis Richardson, 1845) fingerlings

    V. Krasteva M. Yankova, A. Ivanovaa, A. Ivanova / M. Yankova A. Ivanovaa, A. Ivanova / A. Ivanova A. Ivanova / A. Ivanova

    Agricultural Science and Technology, Vol 13, Iss 3, Pp 260-

    2021  Volume 265

    Abstract: Abstract. The aim of the present research is to study the efficacy of rosemary oil as an anesthetic for bighead carp (Hypophthalmichthys nobilis Richardson, 1845) and as an anesthetic used for transport of fingerlings. The fish used in the experiment ... ...

    Abstract Abstract. The aim of the present research is to study the efficacy of rosemary oil as an anesthetic for bighead carp (Hypophthalmichthys nobilis Richardson, 1845) and as an anesthetic used for transport of fingerlings. The fish used in the experiment have an average body weight (BW, g) of 42.13±17.90 and an average total length (TL, cm) of 16.54±2.32. Five treatments are conducted with five experimental concentrations: 0.20 ml.l-1, 0.30 ml.l-1, 0.40 ml.l-1, 0.50 ml.l-1 and 0.60 ml.l-1. For each concentration 10 fish are used or a total of 50 fish. For the transport experiment, 3 concentrations are used: 0.06 ml.l-1, 0.08 ml.l-1 and 0.10 ml.l-1. The applied stocking density is 3 fish/l. A total of 60 fish are used for each concentration or a total of 180 fish. The established results, for the first experiment, show that at concentration of 0.60 ml.l-1 the induction of anesthesia is the fastest (3.46 min). From all tested concentrations the recovery time is the shortest at the lowest concentration – 2.16 min (p≤0.001). The concentration of 0.10 ml.l-1 of rosemary oil can be used for transport of bighead carp fingerlings for a period from 1 to 2 hours. The concentration of 0.08 ml.l-1 can be applied when the duration of the transport is from 1 to 3 hours.
    Keywords anesthesia ; bighead carp ; hypophthalmichthys nobilis ; rosmarinus officinalis ; rosemary oil ; transport ; Agriculture ; S
    Subject code 380
    Language English
    Publishing date 2021-09-01T00:00:00Z
    Publisher Trakia University. Faculty of Agriculture, Stara Zagora
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Conserved Streptococcus pneumoniae spirosomes suggest a single type of transformation pilus in competence.

    Raphaël Laurenceau / Petya V Krasteva / Amy Diallo / Sahra Ouarti / Magalie Duchateau / Christian Malosse / Julia Chamot-Rooke / Rémi Fronzes

    PLoS Pathogens, Vol 11, Iss 4, p e

    2015  Volume 1004835

    Abstract: The success of S. pneumoniae as a major human pathogen is largely due to its remarkable genomic plasticity, allowing efficient escape from antimicrobials action and host immune response. Natural transformation, or the active uptake and chromosomal ... ...

    Abstract The success of S. pneumoniae as a major human pathogen is largely due to its remarkable genomic plasticity, allowing efficient escape from antimicrobials action and host immune response. Natural transformation, or the active uptake and chromosomal integration of exogenous DNA during the transitory differentiated state competence, is the main mechanism for horizontal gene transfer and genomic makeover in pneumococci. Although transforming DNA has been proposed to be captured by Type 4 pili (T4P) in Gram-negative bacteria, and a competence-inducible comG operon encoding proteins homologous to T4P-biogenesis components is present in transformable Gram-positive bacteria, a prevailing hypothesis has been that S. pneumoniae assembles only short pseudopili to destabilize the cell wall for DNA entry. We recently identified a micrometer-sized T4P-like pilus on competent pneumococci, which likely serves as initial DNA receptor. A subsequent study, however, visualized a different structure--short, 'plaited' polymers--released in the medium of competent S. pneumoniae. Biochemical observation of concurrent pilin secretion led the authors to propose that the 'plaited' structures correspond to transformation pili acting as peptidoglycan drills that leave DNA entry pores upon secretion. Here we show that the 'plaited' filaments are not related to natural transformation as they are released by non-competent pneumococci, as well as by cells with disrupted pilus biogenesis components. Combining electron microscopy visualization with structural, biochemical and proteomic analyses, we further identify the 'plaited' polymers as spirosomes: macromolecular assemblies of the fermentative acetaldehyde-alcohol dehydrogenase enzyme AdhE that is well conserved in a broad range of Gram-positive and Gram-negative bacteria.
    Keywords Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
    Subject code 612
    Language English
    Publishing date 2015-04-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Structural basis for c-di-GMP-mediated inside-out signaling controlling periplasmic proteolysis.

    Marcos V A S Navarro / Peter D Newell / Petya V Krasteva / Debashree Chatterjee / Dean R Madden / George A O'Toole / Holger Sondermann

    PLoS Biology, Vol 9, Iss 2, p e

    2011  Volume 1000588

    Abstract: The bacterial second messenger bis-(3'-5') cyclic dimeric guanosine monophosphate (c-di-GMP) has emerged as a central regulator for biofilm formation. Increased cellular c-di-GMP levels lead to stable cell attachment, which in Pseudomonas fluorescens ... ...

    Abstract The bacterial second messenger bis-(3'-5') cyclic dimeric guanosine monophosphate (c-di-GMP) has emerged as a central regulator for biofilm formation. Increased cellular c-di-GMP levels lead to stable cell attachment, which in Pseudomonas fluorescens requires the transmembrane receptor LapD. LapD exhibits a conserved and widely used modular architecture containing a HAMP domain and degenerate diguanylate cyclase and phosphodiesterase domains. c-di-GMP binding to the LapD degenerate phosphodiesterase domain is communicated via the HAMP relay to the periplasmic domain, triggering sequestration of the protease LapG, thus preventing cleavage of the surface adhesin LapA. Here, we elucidate the molecular mechanism of autoinhibition and activation of LapD based on structure-function analyses and crystal structures of the entire periplasmic domain and the intracellular signaling unit in two different states. In the absence of c-di-GMP, the intracellular module assumes an inactive conformation. Binding of c-di-GMP to the phosphodiesterase domain disrupts the inactive state, permitting the formation of a trans-subunit dimer interface between adjacent phosphodiesterase domains via interactions conserved in c-di-GMP-degrading enzymes. Efficient mechanical coupling of the conformational changes across the membrane is realized through an extensively domain-swapped, unique periplasmic fold. Our structural and functional analyses identified a conserved system for the regulation of periplasmic proteases in a wide variety of bacteria, including many free-living and pathogenic species.
    Keywords Biology (General) ; QH301-705.5
    Subject code 572
    Language English
    Publishing date 2011-02-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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