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Sample records for biological properties issledovanie

  1. Biological properties

    Treesearch

    Rebecca E. Ibach

    2005-01-01

    There are numerous biological degradations that wood is exposed to in various environments. Biological damage occurs when a log, sawn product, or final product is not stored, handled, or designed properly. Biological organisms, such as bacteria, mold, stain, decay fungi, insects, and marine borers, depend heavily on temperature and moisture conditions to grow. A higher...

  2. Antimicrobial Peptides: Versatile Biological Properties

    PubMed Central

    Pushpanathan, Muthuirulan; Rajendhran, Jeyaprakash

    2013-01-01

    Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries. PMID:23935642

  3. Allicin: chemistry and biological properties.

    PubMed

    Borlinghaus, Jan; Albrecht, Frank; Gruhlke, Martin C H; Nwachukwu, Ifeanyi D; Slusarenko, Alan J

    2014-08-19

    Allicin (diallylthiosulfinate) is a defence molecule from garlic (Allium sativum L.) with a broad range of biological activities. Allicin is produced upon tissue damage from the non-proteinogenic amino acid alliin (S-allylcysteine sulfoxide) in a reaction that is catalyzed by the enzyme alliinase. Current understanding of the allicin biosynthetic pathway will be presented in this review. Being a thiosulfinate, allicin is a reactive sulfur species (RSS) and undergoes a redox-reaction with thiol groups in glutathione and proteins that is thought to be essential for its biological activity. Allicin is physiologically active in microbial, plant and mammalian cells. In a dose-dependent manner allicin can inhibit the proliferation of both bacteria and fungi or kill cells outright, including antibiotic-resistant strains like methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, in mammalian cell lines, including cancer cells, allicin induces cell-death and inhibits cell proliferation. In plants allicin inhibits seed germination and attenuates root-development. The majority of allicin's effects are believed to be mediated via redox-dependent mechanisms. In sub-lethal concentrations, allicin has a variety of health-promoting properties, for example cholesterol- and blood pressure-lowering effects that are advantageous for the cardio-vascular system. Clearly, allicin has wide-ranging and interesting applications in medicine and (green) agriculture, hence the detailed discussion of its enormous potential in this review. Taken together, allicin is a fascinating biologically active compound whose properties are a direct consequence of the molecule's chemistry.

  4. Optical Properties of Biological Aerosols

    DTIC Science & Technology

    2006-01-01

    in the near zone, so that no simplifying approximation applies. For instan e, theapproximations devised by Johnson and by Bobbert and Vlieger5 have...properties of a sphere inthe vi inity of a plane surfa e," J. Opt. So . Am. A 14, 1505{1514 (1997).17 5. P. A. Bobbert and J. Vlieger, \\Light s

  5. Physical and biological properties of Bazna waters

    PubMed Central

    TRÂMBIŢAŞ, DAN

    2013-01-01

    The healing properties of Bazna waters and their therapeutic indications have been well known since the 18th century. The objective of the present study was to characterize these waters from physical and biological points of view, and to further analyze the nitrogen compounds, especially NH4+. The following physical parameters of the water were analyzed: density (g/cm3), electric resistivity (Ω·m), electric conductivity (cm−1o−1), salinity, The pH analysis of the biological component was performed on samples from 4 basins. Nitrogen compounds were dosed in the form of ammonium ion (NH4+). The physical and chemical proprieties are similar across the basins. Flora and fauna biological components were identified. Ammonium ions were identified in large quantities, but this did not lead to hygienicaly unclean waters. PMID:26527972

  6. Physical and biological properties of Bazna waters.

    PubMed

    Trâmbiţaş, Dan

    2013-01-01

    The healing properties of Bazna waters and their therapeutic indications have been well known since the 18(th) century. The objective of the present study was to characterize these waters from physical and biological points of view, and to further analyze the nitrogen compounds, especially NH4+. The following physical parameters of the water were analyzed: density (g/cm(3)), electric resistivity (Ω·m), electric conductivity (cm(-1)o(-1)), salinity, The pH analysis of the biological component was performed on samples from 4 basins. Nitrogen compounds were dosed in the form of ammonium ion (NH(4+)). The physical and chemical proprieties are similar across the basins. Flora and fauna biological components were identified. Ammonium ions were identified in large quantities, but this did not lead to hygienicaly unclean waters.

  7. Properties and Biological Role of Streptococcal Fratricins

    PubMed Central

    Berg, Kari Helene; Biørnstad, Truls Johan; Johnsborg, Ola

    2012-01-01

    Competence for natural genetic transformation is widespread in the genus Streptococcus. The current view is that all streptococcal species possess this property. In addition to the proteins required for DNA uptake and recombination, competent streptococci secrete muralytic enzymes termed fratricins. Since the synthesis and secretion of these cell wall-degrading enzymes are always coupled to competence development in streptococci, fratricins are believed to carry out an important function associated with natural transformation. This minireview summarizes what is known about the properties of fratricins and discusses their possible biological roles in streptococcal transformation. PMID:22407687

  8. Biological Properties and Therapeutic Applications of Propolis.

    PubMed

    Sforcin, José M

    2016-06-01

    Propolis is a resinous material collected by bees from bud and exudates of the plants, mixed with bee enzymes, pollen and wax. In this review, the biological properties of propolis and some therapeutic applications are discussed. The same biological activities have been investigated until today, using samples from different geographic regions. Thus, the study of the biological properties of a given sample should always be associated with its chemical composition and botanical source, representing a particular sample of a given geographic area, exploring its biological potential and the role of its constituents. Efforts have been carried out to explain propolis' mechanisms of action in vivo and in vitro, but the majority of propolis' targets and actions are still unclear. The number of formulations containing propolis and patents have increased, although propolis extracts have been used deliberately with different recommendations, not always mentioning the chemical composition, vegetal source and the methods of extraction. Clinical studies will help to obtain criterious recommendations in view of the expected outcomes. Further investigation should explore the effects of common compounds found in the samples from all over the world in an attempt to standardize the research on propolis and to obtain new drugs. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Phytochemistry and Biological Properties of Glabridin

    PubMed Central

    Simmler, Charlotte; Pauli, Guido F.; Chen, Shao-Nong

    2013-01-01

    Glabridin, a prenylated isoflavonoid of G. glabra L. roots (European licorice, Fabaceae), has been associated with a wide range of biological properties such as antioxidant, anti-inflammatory, anti-atherogenic, regulation of energy metabolism, estrogenic, neuroprotective, anti-osteoporotic, skin-whitening. While glabridin is one of the most studied licorice flavonoids, a comprehensive literature survey linked to its numerous bioactivities is unavailable. The present review provides a comprehensive description of glabridin as a key chemical and biological marker of G. glabra, by covering both its phytochemical characterization and reported biological activities. Both glabridin and standardized licorice extracts have significant impact on food, dietary supplements (DSs) and cosmetic markets, as evidenced by the amount of available patents and scientific articles since 1976, when glabridin was first described. Nevertheless, a thorough literature survey also reveals that information about the isolation and chemical characterization of this important marker is scattered and less detailed than expected. Accordingly, the first part of this review gathers all analytical and spectroscopic data required for the comprehensive phytochemical characterization of glabridin. The four most frequently described and most relevant bioactivities of glabridin are its anti-inflammatory, anti-atherogenic, estrogenic-like effects, and its capacity to regulate energy metabolism. While all bioactivities reported for glabridin belong to a wide array of targets, its principal biological properties are likely interconnected. To this end, the current state of the literature suggests that the biological activity of glabridin mainly results from its capacity to down-regulate intracellular reactive oxygen species, bind to antioxidant effectors, and act on estrogen receptors, potentially as a plant-based Selective Estrogen Receptor Modulator (phytoSERM). PMID:23850540

  10. [BIOLOGICAL AND IMMUNOCHEMICAL PROPERTIES OF POLYREACTIVE IMMUNOGLOBULINS].

    PubMed

    Bobrovnik, S A; Demchenko, M A; Komisarenko, S V

    2015-01-01

    A previously unknown phenomenon of acquired polyreactivity for serum immunoglobulins, which were subjected either to solutions of KSCN (3.0-5.0 M), low/high pH (pH 2.2-3.0), or heating to 58-60 degrees C, was described by us in 1990 year. Much later, eleven years after that, similar data were published by others, which completely confirmed our results concerning the influence of either chaotropic ions or the drastic shift of pH on immunoglobulins polyreactive properties. Our further investigations of polyreactive serum immunoglobulins (PRIG) properties have shown that the mechanism of non-specific interaction between PRIG and antigens much differs from the mechanism of interaction between specific antibodies and corresponding antigens. Later we have shown that the increasing of PRIG reactivity could be induced in vivo, and PRIG are one of serum components for human or animal sera. Then, it could be suggested that PRIG can perform certain biological functions. Studying of PRIG's effect on the phagocytosis of microbes by peritoneal cells or the tumor growth have shown that PRIG can play a certain role in protecting the body from infections and probably can influence on the development of various pathological processes. Recently we have also found that PRIG IgG contents significantly increases in aged people. These data demonstrate that further investigations of PRIG's immunochemical properties and studying of their biological role in organism protection from various diseases is very intriguing and important.

  11. Arbutus unedo L.: chemical and biological properties.

    PubMed

    Miguel, Maria G; Faleiro, Maria L; Guerreiro, Adriana C; Antunes, Maria D

    2014-09-30

    Arbutus unedo L. (strawberry tree) has a circum-Mediterranean distribution, being found in western, central and southern Europe, north-eastern Africa (excluding Egypt and Libya) and the Canary Islands and western Asia. Fruits of the strawberry tree are generally used for preparing alcoholic drinks (wines, liqueurs and brandies), jams, jellies and marmalades, and less frequently eaten as fresh fruit, despite their pleasing appearance. An overview of the chemical composition of different parts of the plant, strawberry tree honey and strawberry tree brandy will be presented. The biological properties of the different parts of A. unedo and strawberry tree honey will be also overviewed.

  12. [Biological properties of spermatogonial stem cell niches].

    PubMed

    Li, Ling-Ling; Liu, Yang; Jin, Bo; Zhang, Xue-Ming

    2012-04-01

    The self-renewal and differentiation of adult stem cells are closely related to their niches. Naturally, spermatogonial stem cells (SSCs) are the only adult stem cells in the body, which can transfer genetic information into the offspring. An insight into the modulation of the self-renewal and differentiation of SSCs can help elucidate the mechanisms of spermatogenesis and investigate the proliferation and differentiation of other adult stem cells. Therefore, the SSC system provides an ideal model for researches on the adult stem cell niche. More and more evidence indicates that the self-renewal and differentiation of SSCs are regulated by their niches. Based on our previous work and other related findings recently reported, this article presents an overview on the biological properties of SSC niches and their relationship with the self-renewal and differentiation of SSCs, focusing on the basic properties and components of SSC niches and various regulatory factors they produce.

  13. Mechanical properties of nanostructure of biological materials

    NASA Astrophysics Data System (ADS)

    Ji, Baohua; Gao, Huajian

    2004-09-01

    Natural biological materials such as bone, teeth and nacre are nanocomposites of protein and mineral with superior strength. It is quite a marvel that nature produces hard and tough materials out of protein as soft as human skin and mineral as brittle as classroom chalk. What are the secrets of nature? Can we learn from this to produce bio-inspired materials in the laboratory? These questions have motivated us to investigate the mechanics of protein-mineral nanocomposite structure. Large aspect ratios and a staggered alignment of mineral platelets are found to be the key factors contributing to the large stiffness of biomaterials. A tension-shear chain (TSC) model of biological nanostructure reveals that the strength of biomaterials hinges upon optimizing the tensile strength of the mineral crystals. As the size of the mineral crystals is reduced to nanoscale, they become insensitive to flaws with strength approaching the theoretical strength of atomic bonds. The optimized tensile strength of mineral crystals thus allows a large amount of fracture energy to be dissipated in protein via shear deformation and consequently enhances the fracture toughness of biocomposites. We derive viscoelastic properties of the protein-mineral nanostructure and show that the toughness of biocomposite can be further enhanced by the viscoelastic properties of protein.

  14. Optical property measurement from layered biological media

    NASA Astrophysics Data System (ADS)

    Muller, Matthew R.

    1998-12-01

    Near infrared (NIR) photon reflectance spectroscopy is applied to measurement of blood concentration and its oxygen saturation within biological tissue. The measurement relies upon the changes in photon absorption of hemoglobin in the tissue as changes occur in the hemoglobin concentration and oxygen content. In the present study, NIR light is introduced at the skin surface and the optical properties (absorption and scattering) within the underlying tissue are determined from the resulting surface reflectance. Typically the tissue is modeled as a homogeneous mixture of bloodless tissue and blood, and the model incorporates the physical relationship between the surface reflectance and the optical properties of the tissue. The skin and underlying tissue, although heterogeneous, have a characteristic layered structure. These layers can be differentiated optically. The modeling and the inverse problem of measuring the optical properties in each of the tissue layers from the surface reflectance have been the subject of much attention by a number of investigators. Nonetheless, quantification of the relationship between surface reflectance and the optical properties of layered tissue has not been well understood nor well described. In the forward problem, tissue optical properties yield surface reflectance profiles (SRPs). Surface reflectance profiles, or SRPs, from diffusive media consisting of two layers are calculated using numerical solutions to the Boltzmann equation. Experimental SRPs are also measured in vitro from a test medium and in vivo from the calf of human subjects. This study provides a new approach to solving the inverse problem of determining optical properties from SRPs. To solve the inverse problem, an effective diffusion constant (Ke) is determined for the layered media. The Ke is the diffusion constant of an equivalent homogeneous medium which best fits the SRP of the layered medium. The departure from Ke of the SRP for a layered media is captured

  15. Biophysical and biological properties of quadruplex oligodeoxyribonucleotides

    PubMed Central

    Đapić, Virna; Abdomerović, Vedra; Marrington, Rachel; Peberdy, Jemma; Rodger, Alison; Trent, John O.; Bates, Paula J.

    2003-01-01

    Single-stranded guanosine-rich oligodeoxyribonucleotides (GROs) have a propensity to form quadruplex structures that are stabilized by G-quartets. In addition to intense speculation about the role of G-quartet formation in vivo, there is considerable interest in the therapeutic potential of quadruplex oligonucleotides as aptamers or non-antisense antiproliferative agents. We previously have described several GROs that inhibit proliferation and induce apoptosis in cancer cell lines. The activity of these GROs was related to their ability to bind to a specific cellular protein (GRO-binding protein, which has been tentatively identified as nucleolin). In this report, we describe the physical properties and biological activity of a group of 12 quadruplex oligonucleotides whose structures have been characterized previously. This group includes the thrombin-binding aptamer, an anti-HIV oligonucleotide, and several quadruplexes derived from telomere sequences. Thermal denaturation and circular dichroism (CD) spectropolarimetry were utilized to investigate the stability, reversibility and ion dependence of G-quartet formation. The ability of each oligonucleotide to inhibit the proliferation of cancer cells and to compete for binding to the GRO-binding protein was also examined. Our results confirm that G-quartet formation is essential for biological activity of GROs and show that, in some cases, quadruplex structures formed in the presence of potassium ions are significantly more active than those formed in the presence of sodium ions. However, not all quadruplex structures exhibit antiproliferative effects, and the most accurate factor in predicting biological activity was the ability to bind to the GRO-binding protein. Our data also indicate that the CD spectra of quadruplex oligonucleotides may be more complex than previously thought. PMID:12682360

  16. The Optical Properties of Biological Tissue.

    NASA Astrophysics Data System (ADS)

    Bews, Jeffrey Alan

    The ability of light to propagate through biological tissue has found much application in medicine (ie. Photodynamic therapy and Diaphanography). However, a poor understanding of this transport phenomenon has served to limit the effectiveness of those modalities employing it in their operation. This thesis is a study of light propagation through biological tissue, its goal being to improve on the lack of knowledge that presently exists. A spectrophotometer type instrument (DICOM-8) was developed to measure the diffuse spectra extinction of biological tissue. Results were obtained for both normal and diseased breast tissue. Extinction curves for the two tissues exhibited a similar shape (extinction monotonically decreasing with increasing wavelength) but differed in magnitude below 700 nm with carcinoma possessing a higher extinction than normal. Data obtained from these tissue measurements served as the basis for developing a homogeneous liquid (TEM) for simulating the optical properties of tissue over the range 550 to 900 nm. Bench-top Diaphanography studies carried out on a breast phantom constructed of TEM demonstrated the improved tumor visualization attainable with short wavelength light. TEM also functioned as a test medium in which light distributions resulting from highly controlled irradiation geometries (isotropic point and planar sources) were measured and compared with those predicted by Linear Transport (LT) theory. The mean free path (MFP) of TEM ranged from 0.206 mm at 550 nm to 0.495 mm at 900 nm and was found to be directly proportional to the square of the wavelength. The scatter/absorption coefficient (c) was 0.9986459 at 550 nm and 0.9997315 at 850 nm. Agreement between experimental and theoretical distributions was found to be extremely good. Theoretical distributions generated with LT theory revealed the fact that small changes in MFP will have little effect on light transport. Similar changes in c, meanwhile, will drastically alter the

  17. Chapter 5:Biological Properties of Wood

    Treesearch

    Rebecca E. Ibach

    2013-01-01

    There are numerous biological degradations that wood is exposed to in various environments. Biological damage occurs when a log, sawn product, or final product is not stored, handled, or designed properly. Biological organisms such as bacteria, mold, stain, decay fungi, insects, and marine borers depend heavily on temperature and moisture conditions to grow. Figure 5.1...

  18. VISCOELASTIC PROPERTIES OF A BIOLOGICAL HYDROGEL PRODUCED FROM SOYBEAN OIL

    USDA-ARS?s Scientific Manuscript database

    Hydrogels formed from biopolymers or natural sources have special advantages because of their biodegradable and biocompatible properties. The viscoelastic properties of a newly developed biological hydrogel made from modified vegetable oil, epoxidized soybean oil (ESO) were investigated. The mater...

  19. Non-Photoinduced Biological Properties of Verteporfin.

    PubMed

    Gibault, Floriane; Corvaisier, Matthieu; Bailly, Fabrice; Huet, Guillemette; Melnyk, Patricia; Cotelle, Philippe

    2016-01-01

    Verteporfin is a porphyrinic photosensitizer clinically used for the photodynamic treatment of age-related macular degeneration. It has been identified almost simultaneously as a YAP/TEAD and an autophagosome inhibitor. Over the last few years, YAP (TAZ), the downstream effectors of the Hippo pathway, have emerged as promising anticancer targets, as shown by several experimental lines of evidence, showing the overproduction of YAP in several cancers. However, YAP was also found to be closely connected to autophagy, mitochondria and reactive oxygen/nitrogen species. We herein, review the recent studies where VP was used without photoactivation as a YAP/TEAD inhibitor or protein oligomerization promoter, focusing on its effects on the YAP/TEAD gene targets and other biomarkers related to autophagy. Since the identification of VP as YAP/TEAD inhibitor, several in vitro and in vivo studies have revealed the new potential of this molecule in different cancers, where YAP is overexpressed. However, detailed structural information about its interaction with YAP is still lacking. Concomitantly, VP was identified as autophagosome inhibitor by promoting oligomerization of p62. Moreover, VP proves to be tumor-selective proteotoxic (by oligomerization of p62, STAT3) in colorectal cancer. Knowledge on the biological properties of the only YAP inhibitor available to date is vital for its pharmacological use on cellular and animal models. VP is a multi-target drug interacting with several proteins implicated in major cellular processes. Although this does not impact its clinical use, VP does not seem to be the ideal drug for pharmacological inhibitions of YAP/TEAD.

  20. Mechanical and biological properties of keratose biomaterials.

    PubMed

    de Guzman, Roche C; Merrill, Michelle R; Richter, Jillian R; Hamzi, Rawad I; Greengauz-Roberts, Olga K; Van Dyke, Mark E

    2011-11-01

    The oxidized form of extractable human hair keratin proteins, commonly referred to as keratose, is gaining interest as a biomaterial for multiple tissue engineering studies including those directed toward peripheral nerve, spinal cord, skin, and bone regeneration. Unlike its disulfide cross-linked counterpart, kerateine, keratose does not possess a covalently cross-linked network structure and consequently displays substantially different characteristics. In order to understand its mode(s) of action and potential for clinical translatability, detailed characterization of the composition, physical properties, and biological responses of keratose biomaterials are needed. Keratose was obtained from end-cut human hair fibers by peracetic acid treatment, followed by base extraction, and subsequent dialysis. Analysis of lyophilized keratose powder determined that it contains 99% proteins by mass with amino acid content similar to human hair cortex. Metallic elements were also found in minute quantities. Protein oxidation led to disulfide bond cleavage and drastic reduction of free thiols due to conversion of sulfhydryl to sulfonic acid, chain fragmentation, and amino acid modifications. Mass spectrometry identified the major protein constituents as a heterogeneous mixture of 15 hair keratins (type I: K31-35 and K37-39, and type II: K81-86) with small amounts of epithelial keratins which exist in monomeric, dimeric, multimeric, and even degraded forms. Re-hydration with PBS enabled molecular assembly into an elastic solid-like hydrogel. Highly-porous scaffolds formed by lyophilization of the gel had the compression behavior of a cellular foam material and reverted back to gel upon wetting. Cytotoxicity assays showed that the EC50 for various cell lines were attained at 8-10 mg/mL keratose, indicating the non-toxic nature of the material. Implantation in mouse subcutaneous tissue pockets demonstrated that keratose resorption follows a rectangular hyperbolic regression

  1. NANOSILVER MOVEMENT THROUGH BIOLOGICAL BARRIERS RELATES TO PHYSICOCHEMICAL PROPERTIES

    EPA Science Inventory

    Linking the physicochemical (PC) properties of engineered nanomaterials (NM) to their biological activity is critical for identifying their (toxic) mode of action, and developing appropriate and effective risk assessment guidelines. Particle surface charge (zeta potential), surfa...

  2. NANOSILVER MOVEMENT THROUGH BIOLOGICAL BARRIERS RELATES TO PHYSICOCHEMICAL PROPERTIES

    EPA Science Inventory

    Linking the physicochemical (PC) properties of engineered nanomaterials (NM) to their biological activity is critical for identifying their (toxic) mode of action, and developing appropriate and effective risk assessment guidelines. Particle surface charge (zeta potential), surfa...

  3. Dynamic and rheological properties of soft biological cell suspensions

    PubMed Central

    Yazdani, Alireza; Li, Xuejin

    2016-01-01

    Quantifying dynamic and rheological properties of suspensions of soft biological particles such as vesicles, capsules, and red blood cells (RBCs) is fundamentally important in computational biology and biomedical engineering. In this review, recent studies on dynamic and rheological behavior of soft biological cell suspensions by computer simulations are presented, considering both unbounded and confined shear flow. Furthermore, the hemodynamic and hemorheological characteristics of RBCs in diseases such as malaria and sickle cell anemia are highlighted. PMID:27540271

  4. About emergent properties and complexity in biological theories.

    PubMed

    Benci, Vieri; Freguglia, Paolo

    2004-01-01

    Our aim is to present some ideas about the notion of scientific theory which includes the biological theories. We examine relationships among theories and examples of theoretical situations. In this context we propose definitions of emergent property and complexity. These definitions are exemplified by the development of some biological theories.

  5. [Preparations and biological properties of chiral compounds].

    PubMed

    Sinko, Goran

    2005-12-01

    Enantiomers of chiral compounds may express various biological activities and also different toxicities. Examples of different pharmacological effects of some chiral drugs such as fluoxetine, penicillamine, ibuprofen and albuterol are provided in this paper. Due to possible differences in activity, the chiral drugs are required to be pure enantiomeric compounds in order to be more effective and safer to use. In the laboratory, enantiomers are mainly synthesized as racemates (an equimolar mixture of enantiomers) while in biological pathways only one enantiomeric form is produced, such as amino acids, sugars and lipids. This paper presents the principles of chirality, general information about enantiomers and their biological aspects. It gives an outline of stereoselective methods for chromatographic resolution of enantiomers with stereoselective protein stationary phases, i.e. capillary electrochromatography (CEC) and high performance liquid chromatography (HPLC). The use of enzyme biotransformations (hydrolysis, oxidation and reduction) in chiral syntheses of carboxyl-, phosphoryl- or beta-hydroxy esters, alcohols, epoxides and cis-carboxyl sulphoxide is described. This article also includes an example of lipase stereoselectivity improvement by amino acid mutations within the enzyme active site.

  6. Elastic proteins: biological roles and mechanical properties.

    PubMed Central

    Gosline, John; Lillie, Margo; Carrington, Emily; Guerette, Paul; Ortlepp, Christine; Savage, Ken

    2002-01-01

    The term 'elastic protein' applies to many structural proteins with diverse functions and mechanical properties so there is room for confusion about its meaning. Elastic implies the property of elasticity, or the ability to deform reversibly without loss of energy; so elastic proteins should have high resilience. Another meaning for elastic is 'stretchy', or the ability to be deformed to large strains with little force. Thus, elastic proteins should have low stiffness. The combination of high resilience, large strains and low stiffness is characteristic of rubber-like proteins (e.g. resilin and elastin) that function in the storage of elastic-strain energy. Other elastic proteins play very different roles and have very different properties. Collagen fibres provide exceptional energy storage capacity but are not very stretchy. Mussel byssus threads and spider dragline silks are also elastic proteins because, in spite of their considerable strength and stiffness, they are remarkably stretchy. The combination of strength and extensibility, together with low resilience, gives these materials an impressive resistance to fracture (i.e. toughness), a property that allows mussels to survive crashing waves and spiders to build exquisite aerial filters. Given this range of properties and functions, it is probable that elastic proteins will provide a wealth of chemical structures and elastic mechanisms that can be exploited in novel structural materials through biotechnology. PMID:11911769

  7. Biological properties of olive oil phytochemicals.

    PubMed

    Visioli, Francesco; Galli, Claudio

    2002-01-01

    Olive oil is the principal source of fat in the Mediterranean diet, which has been associated with a lower incidence of coronary heart disease and certain cancers. Extra-virgin olive oil contains a considerable amount of phenolic compounds, for example, hydroxytyrosol and oleuropein, that are responsible for its peculiar taste and for its high stability. Evidence is accumulating to demonstrate that olive oil phenolics are powerful antioxidants, both in vitro and in vivo; also, they exert other potent biological activities that could partially account for the observed healthful effects of the Mediterranean diet.

  8. Synthetic biology and intellectual property rights: six recommendations.

    PubMed

    Minssen, Timo; Rutz, Berthold; van Zimmeren, Esther

    2015-02-01

    On 26th November 2013, the Danish Agency for Science, Technology and Innovation organized an expert meeting on "Synthetic Biology & Intellectual Property Rights" in Copenhagen sponsored by the European Research Area Network in Synthetic Biology (ERASynBio). The meeting brought together ten experts from different countries with a variety of professional backgrounds to discuss emerging challenges and opportunities at the interface of synthetic biology and intellectual property rights. The aim of this article is to provide a summary of the major issues and recommendations discussed during the meeting.

  9. SOME CHEMICAL PROPERTIES UNDERLYING ARSENIC'S BIOLOGICAL ACTIVITY

    EPA Science Inventory

    ABSTRACT

    In this paper some of the chemical properties of arsenicals (atomic
    and molecular orbitals, electronegativity, valence state, changes between
    valence state, nucleophilicity, the hard/soft acid/base principle) that may
    account for some of the b...

  10. SOME CHEMICAL PROPERTIES UNDERLYING ARSENIC'S BIOLOGICAL ACTIVITY

    EPA Science Inventory

    ABSTRACT

    In this paper some of the chemical properties of arsenicals (atomic
    and molecular orbitals, electronegativity, valence state, changes between
    valence state, nucleophilicity, the hard/soft acid/base principle) that may
    account for some of the b...

  11. Insight into Biological Apatite: Physiochemical Properties and Preparation Approaches

    PubMed Central

    Liu, Quan; Matinlinna, Jukka Pekka; Chen, Zhuofan; Pan, Haobo

    2013-01-01

    Biological apatite is an inorganic calcium phosphate salt in apatite form and nano size with a biological derivation. It is also the main inorganic component of biological hard tissues such as bones and teeth of vertebrates. Consequently, biological apatite has a wide application in dentistry and orthopedics by using as dental fillers and bone substitutes for bone reconstruction and regeneration. Given this, it is of great significance to obtain a comprehensive understanding of its physiochemical and biological properties. However, upon the previous studies, inconsistent and inadequate data of such basic properties as the morphology, crystal size, chemical compositions, and solubility of biological apatite were reported. This may be ascribed to the differences in the source of raw materials that biological apatite are made from, as well as the effect of the preparation approaches. Hence, this paper is to provide some insights rather than a thorough review of the physiochemical properties as well as the advantages and drawbacks of various preparation methods of biological apatite. PMID:24078928

  12. Intellectual property conundrum for the biological sciences.

    PubMed

    Olds, James L

    2004-03-01

    Policy regarding academically generated biomedical intellectual property (IP) has been shaped by two important events: the Vannevar Bush report to then President Roosevelt in 1945 and the Bayh-Dole Act of 1980. This policy, which vests the intellectual property produced from federally funded biomedical research from the government to the academic institution, was designed to promote technology transfer and thus promote the health of the U.S. economy. However, the policy has led to significant challenges, particularly in implementation. Here it is argued that the difficulties are due to differences in the structure of motivations between biomedical scientists, institutional officials, and private sector entrepreneurs. Understanding these differences may lead to a review of policy with the goal of enhancing technology transfer for the future. Copyright 2004 Wiley-Liss, Inc.

  13. The diverse biological properties of the chemically inert noble gases.

    PubMed

    Winkler, David A; Thornton, Aaron; Farjot, Géraldine; Katz, Ira

    2016-04-01

    The noble gases represent an intriguing scientific paradox. They are extremely inert chemically but display a remarkable spectrum of clinically useful biological properties. Despite a relative paucity of knowledge of their mechanisms of action, some of the noble gases have been used successfully in the clinic. Studies with xenon have suggested that the noble gases as a class may exhibit valuable biological properties such as anaesthesia; amelioration of ischemic damage; tissue protection prior to transplantation; analgesic properties; and a potentially wide range of other clinically useful effects. Xenon has been shown to be safe in humans, and has useful pharmacokinetic properties such as rapid onset, fast wash out etc. The main limitations in wider use are that: many of the fundamental biochemical studies are still lacking; the lighter noble gases are likely to manifest their properties only under hyperbaric conditions, impractical in surgery; and administration of xenon using convectional gaseous anaesthesia equipment is inefficient, making its use very expensive. There is nonetheless a significant body of published literature on the biochemical, pharmacological, and clinical properties of noble gases but no comprehensive reviews exist that summarize their properties and the existing knowledge of their models of action at the molecular (atomic) level. This review provides such an up-to-date summary of the extensive, useful biological properties of noble gases as drugs and prospects for wider application of these atoms.

  14. Measurement of ultrasonic properties of muscle and blood biological phantoms

    NASA Astrophysics Data System (ADS)

    Ortega, R.; Téllez, A.; Leija, L.; Vera, A.

    2010-01-01

    Oncology hyperthermia refers to an artificial elevation of temperature in biological tissue to remove tumor cells. This temperature increase is reached by applying ultrasound or electromagnetic waves. Working with biological tissues implies a high effort; furthermore, biological material changes its properties with time. Also, it is necessary a knowledge of the handling of biological material and a specialized infrastructure. For these reasons, for some years our research laboratory has dedicated part of its researches to develop mimicking materials to emulate muscle and other tissue ultrasonic properties. A blood phantom was developed in our laboratory for its use in the transit time flow measurement (blood flow). The properties of interest for the muscle and for the blood phantoms are ultrasonic attenuation and ultrasound velocity. This work refers to the phantom preparation and their ultrasonic properties measurement. These phantoms emulate the mentioned ultrasonic characteristics. In the case of muscle, there are two types of phantoms: solid phantom with graphite and phantom with scatterers. The procedure of preparation of the phantoms is described. They have a different composition to that published for Doppler blood phantoms. Some ultrasonic properties of muscle and of blood have been already published and they are referred to one temperature. An originality of the results reported in this paper is that the behavior of the ultrasonic properties is presented at different temperatures: ranging from 22 ∘C to 470 ∘C. This range includes the temperatures used in our experimental work in hyperthermia treatment.

  15. A method to measure nanomechanical properties of biological objects

    SciTech Connect

    Ploscariu, Nicoleta; Szoszkiewicz, Robert

    2013-12-23

    We postulate that one will be able to quantitatively infer changes in the mechanical properties of proteins, cells, and other biological objects (BO) by measuring the shifts of several thermally excited resonance frequencies of atomic force microscopy cantilevers in contact with BOs. Here, we provide a method to extract spring constants and molecular damping factors of BOs in biologically relevant phosphate buffered saline medium and using compliant AFM cantilevers with a small aspect ratio (a ratio of length to width)

  16. Using electron microscopy to calculate optical properties of biological samples.

    PubMed

    Wu, Wenli; Radosevich, Andrew J; Eshein, Adam; Nguyen, The-Quyen; Yi, Ji; Cherkezyan, Lusik; Roy, Hemant K; Szleifer, Igal; Backman, Vadim

    2016-11-01

    The microscopic structural origins of optical properties in biological media are still not fully understood. Better understanding these origins can serve to improve the utility of existing techniques and facilitate the discovery of other novel techniques. We propose a novel analysis technique using electron microscopy (EM) to calculate optical properties of specific biological structures. This method is demonstrated with images of human epithelial colon cell nuclei. The spectrum of anisotropy factor g, the phase function and the shape factor D of the nuclei are calculated. The results show strong agreement with an independent study. This method provides a new way to extract the true phase function of biological samples and provides an independent validation for optical property measurement techniques.

  17. Using electron microscopy to calculate optical properties of biological samples

    PubMed Central

    Wu, Wenli; Radosevich, Andrew J.; Eshein, Adam; Nguyen, The-Quyen; Yi, Ji; Cherkezyan, Lusik; Roy, Hemant K.; Szleifer, Igal; Backman, Vadim

    2016-01-01

    The microscopic structural origins of optical properties in biological media are still not fully understood. Better understanding these origins can serve to improve the utility of existing techniques and facilitate the discovery of other novel techniques. We propose a novel analysis technique using electron microscopy (EM) to calculate optical properties of specific biological structures. This method is demonstrated with images of human epithelial colon cell nuclei. The spectrum of anisotropy factor g, the phase function and the shape factor D of the nuclei are calculated. The results show strong agreement with an independent study. This method provides a new way to extract the true phase function of biological samples and provides an independent validation for optical property measurement techniques. PMID:27896013

  18. Fundamental Investigations of the Tribological Properties of Biological Interfaces

    DTIC Science & Technology

    2005-10-01

    Final Technical Report Air Force Contract # F49620-02-1-0346 Fundamental Investigations of the Tribological Properties of Biological Interfaces For... tribological systems lubricated by aqueous solutions. The proposed experimental program will be aimed at measuring interfacial forces over a range of...structure) in determining the adsorption, load- bearing , and frictional properties of self-assembling waterborne organic coatings. It will also examine

  19. Mechanical properties of biological specimens explored by atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Kasas, S.; Longo, G.; Dietler, G.

    2013-04-01

    The atomic force microscope is a widely used surface scanning apparatus capable of reconstructing at a nanometric scale resolution the 3D morphology of biological samples. Due to its unique sensitivity, it is now increasingly used as a force sensor, to characterize the mechanical properties of specimens with a similar lateral resolution. This unique capability has produced, in the last years, a vast increase in the number of groups that have exploited the versatility and sensitivity of the instrument to explore the nanomechanics of various samples in the fields of biology, microbiology and medicine. In this review we outline the state of the art in this field, reporting the most interesting recent works involving the exploration of the nanomechanical properties of various biological samples.

  20. Physical, chemical, and biological properties of wonder kelp--Laminaria.

    PubMed

    Kim, Se-Kwon; Bhatnagar, Ira

    2011-01-01

    Laminaria is a kelp that finds its place in the brown algae family. It has been an area of study for past many years, and its wonderful biological properties have always attracted medical professionals and researchers to explore more and more from this wonder kelp. The constituents of Laminaria include iodine, potassium, magnesium, calcium and iron. Iodine compounds, TEA-hydroiodide in particular, are great lipolytic agents as they stimulate lipase activity. Laminarins on the other hand are used as a tumor angiogenic blocker. This genus of the kelps is also rich in algin, a high molecular weight polysaccharide that forms viscous colloidal solutions or gels in water leading to the use of kelp derivatives as bulk laxatives. It has great applications in cosmeceutical science, as well as some antibacterial properties have also been assigned to Laminaria. A deeper insight into the physical, biological, and chemical properties of this wonder kelp would lead to further exploitation of Laminaria for medicinal and cosmeceutical purpose.

  1. How divergence mechanisms influence disassortative mixing property in biology

    NASA Astrophysics Data System (ADS)

    Xu, Chunsui; Liu, Zengrong; Wang, Ruiqi

    2010-02-01

    The duplication-divergence mechanism of network growth has been widely investigated, especially in gene and protein networks. Both the duplication and divergence have a key role in biological network evolution. However, the relative roles of these mechanisms in the influence of disassortative property in protein interaction networks remain to be clarified. It has been shown that duplication can indeed make protein networks evolve towards disassortative networks. To make the relationship between the disassortative property and the duplication-divergence mechanism more clear, we further discuss how the divergence mechanism influences the disassortative property. We tested four different divergence mechanisms, i.e., node deletion, edge deletion, edge addition, and edge rewiring to study their effects on disassortative property. Our study highlights the crucial roles of different divergence evolution mechanisms.

  2. Topological properties of robust biological and computational networks

    PubMed Central

    Navlakha, Saket; He, Xin; Faloutsos, Christos; Bar-Joseph, Ziv

    2014-01-01

    Network robustness is an important principle in biology and engineering. Previous studies of global networks have identified both redundancy and sparseness as topological properties used by robust networks. By focusing on molecular subnetworks, or modules, we show that module topology is tightly linked to the level of environmental variability (noise) the module expects to encounter. Modules internal to the cell that are less exposed to environmental noise are more connected and less robust than external modules. A similar design principle is used by several other biological networks. We propose a simple change to the evolutionary gene duplication model which gives rise to the rich range of module topologies observed within real networks. We apply these observations to evaluate and design communication networks that are specifically optimized for noisy or malicious environments. Combined, joint analysis of biological and computational networks leads to novel algorithms and insights benefiting both fields. PMID:24789562

  3. Topological properties of robust biological and computational networks.

    PubMed

    Navlakha, Saket; He, Xin; Faloutsos, Christos; Bar-Joseph, Ziv

    2014-07-06

    Network robustness is an important principle in biology and engineering. Previous studies of global networks have identified both redundancy and sparseness as topological properties used by robust networks. By focusing on molecular subnetworks, or modules, we show that module topology is tightly linked to the level of environmental variability (noise) the module expects to encounter. Modules internal to the cell that are less exposed to environmental noise are more connected and less robust than external modules. A similar design principle is used by several other biological networks. We propose a simple change to the evolutionary gene duplication model which gives rise to the rich range of module topologies observed within real networks. We apply these observations to evaluate and design communication networks that are specifically optimized for noisy or malicious environments. Combined, joint analysis of biological and computational networks leads to novel algorithms and insights benefiting both fields.

  4. Physicochemical Properties of Ion Pairs of Biological Macromolecules.

    PubMed

    Iwahara, Junji; Esadze, Alexandre; Zandarashvili, Levani

    2015-09-30

    Ion pairs (also known as salt bridges) of electrostatically interacting cationic and anionic moieties are important for proteins and nucleic acids to perform their function. Although numerous three-dimensional structures show ion pairs at functionally important sites of biological macromolecules and their complexes, the physicochemical properties of the ion pairs are not well understood. Crystal structures typically show a single state for each ion pair. However, recent studies have revealed the dynamic nature of the ion pairs of the biological macromolecules. Biomolecular ion pairs undergo dynamic transitions between distinct states in which the charged moieties are either in direct contact or separated by water. This dynamic behavior is reasonable in light of the fundamental concepts that were established for small ions over the last century. In this review, we introduce the physicochemical concepts relevant to the ion pairs and provide an overview of the recent advancement in biophysical research on the ion pairs of biological macromolecules.

  5. Physicochemical Properties of Ion Pairs of Biological Macromolecules

    PubMed Central

    Iwahara, Junji; Esadze, Alexandre; Zandarashvili, Levani

    2015-01-01

    Ion pairs (also known as salt bridges) of electrostatically interacting cationic and anionic moieties are important for proteins and nucleic acids to perform their function. Although numerous three-dimensional structures show ion pairs at functionally important sites of biological macromolecules and their complexes, the physicochemical properties of the ion pairs are not well understood. Crystal structures typically show a single state for each ion pair. However, recent studies have revealed the dynamic nature of the ion pairs of the biological macromolecules. Biomolecular ion pairs undergo dynamic transitions between distinct states in which the charged moieties are either in direct contact or separated by water. This dynamic behavior is reasonable in light of the fundamental concepts that were established for small ions over the last century. In this review, we introduce the physicochemical concepts relevant to the ion pairs and provide an overview of the recent advancement in biophysical research on the ion pairs of biological macromolecules. PMID:26437440

  6. Physical properties of biological entities: an introduction to the ontology of physics for biology.

    PubMed

    Cook, Daniel L; Bookstein, Fred L; Gennari, John H

    2011-01-01

    As biomedical investigators strive to integrate data and analyses across spatiotemporal scales and biomedical domains, they have recognized the benefits of formalizing languages and terminologies via computational ontologies. Although ontologies for biological entities-molecules, cells, organs-are well-established, there are no principled ontologies of physical properties-energies, volumes, flow rates-of those entities. In this paper, we introduce the Ontology of Physics for Biology (OPB), a reference ontology of classical physics designed for annotating biophysical content of growing repositories of biomedical datasets and analytical models. The OPB's semantic framework, traceable to James Clerk Maxwell, encompasses modern theories of system dynamics and thermodynamics, and is implemented as a computational ontology that references available upper ontologies. In this paper we focus on the OPB classes that are designed for annotating physical properties encoded in biomedical datasets and computational models, and we discuss how the OPB framework will facilitate biomedical knowledge integration.

  7. Biological activities and medicinal properties of Gokhru (Pedalium murex L.)

    PubMed Central

    Rajashekar, V; Rao, E Upender; P, Srinivas

    2012-01-01

    Bada Gokhru (Pedalium murex L.) is perhaps the most useful traditional medicinal plant in India. Each part of the neem tree has some medicinal property and is thus commercially exploitable. During the last five decades, apart from the chemistry of the Pedalium murex compounds, considerable progress has been achieved regarding the biological activity and medicinal applications of this plant. It is now considered as a valuable source of unique natural products for development of medicines against various diseases and also for the development of industrial products. This review gives a bird's eye view mainly on the biological activities of some of this compounds isolated, pharmacological actions of the extracts, clinical studies and plausible medicinal applications of gokharu along with their safety evaluation. PMID:23569975

  8. Chiral hydroxy phosphonates: synthesis, configuration and biological properties

    NASA Astrophysics Data System (ADS)

    Kolodiazhnyi, Oleg I.

    2006-03-01

    Published data on the synthesis, absolute configurations and biological properties of chiral hydroxy phosphonates are generalised and described systematically. Examples of asymmetric synthesis of hydroxy phosphonates by the phospho-aldol reaction, reduction of keto phosphonates, chemo-enzymatic approach, and so on are discussed. Methods for determination of the optical purity and absolute configuration of hydroxy phosphonates using modification by chiral reagents, NMR, circular dichroism, GLC and HPLC on columns with chiral sorbents are considered. The significance of hydroxy phosphonates as promising compounds for the development of new drugs and bioregulators is demonstrated.

  9. Biological Properties of Tocotrienols: Evidence in Human Studies

    PubMed Central

    Meganathan, Puvaneswari; Fu, Ju-Yen

    2016-01-01

    Vitamin E has been recognized as an essential vitamin since their discovery in 1922. Although the functions of tocopherols are well established, tocotrienols have been the unsung heroes of vitamin E. Due to their structural differences, tocotrienols were reported to exert distinctive properties compared to tocopherols. While most vegetable oils contain higher amount of tocopherols, tocotrienols were found abundantly in palm oil. Nature has made palm vitamin E to contain up to 70% of total tocotrienols, among which alpha-, gamma- and delta-tocotrienols are the major constituents. Recent advancements have shown their biological properties in conferring protection against cancer, cardiovascular diseases, neurodegeneration, oxidative stress and immune regulation. Preclinical results of these physiological functions were translated into clinical trials gaining global attention. This review will discuss in detail the evidence in human studies to date in terms of efficacy, population, disease state and bioavailability. The review will serve as a platform to pave the future direction for tocotrienols in clinical settings. PMID:27792171

  10. Bioactive compounds in cranberries and their biological properties.

    PubMed

    Côté, J; Caillet, S; Doyon, G; Sylvain, J-F; Lacroix, M

    2010-08-01

    Cranberries are healthy fruit that contribute color, flavor, nutritional value, and functionality. They are one of only three fruits native to America. Over the past decade, public interest for the North American cranberry (Vaccinium macrocarpon) has been rising with reports of their potential health benefits linked to the numerous phytochemicals present in the fruit--the anthocyanins, the flavonols, the flavan-3-ols, the proanthocyanidins, and the phenolic acid derivatives. The presence of these phytochemicals appears to be responsible for the cranberry property of preventing many diseases and infections, including cardiovascular diseases, various cancers, and infections involving the urinary tract, dental health, and Helicobacter pylori-induced stomach ulcers and cancers. Recent years have seen important breakthroughs in our understanding of the mechanisms through which these compounds exert their beneficial biological effects, yet these remain to be scientifically substantiated. In this paper these characteristics, as well as the antioxidant, radical scavenging, antibacterial, antimutagen, and anticarcinogen properties of cranberry major bioactive compounds are explained.

  11. Mechanical and biological properties of oxidized horn keratin.

    PubMed

    Zhang, Quanbin; Shan, Guanghua; Cao, Ping; He, Jia; Lin, Zhongshi; Huang, Yaoxiong; Ao, Ningjian

    2015-02-01

    The goal of this study was to investigate the mechanical and biological properties of oxidized keratin materials, which were obtained by using buffalo horns to oxidize. It could provide a way to evaluate their potential for clinical translatability. The characterization on their composition, mechanical properties, and biological responses was performed. It is found that the oxidation process could lead the disulfide bond to break down and then to form sulfonic acid, or even make partial peptide chain to be fragment for the new modification of amino acid. Hence the oxidized horn keratins have lower thermal stability and hydrolytic stability in comparison with horn keratin, but the degradation products of oxidized horn keratins have no significant difference. In addition, the mechanical properties of oxidized horn keratins are poorer than that of horn keratin, but the oxidized horn keratins still have disulfide bonds to form a three-dimensional structure, which benefits for their mechanical properties. The fracture toughness of oxidized horn keratins increases with the increase in the degree of oxidation. After oxidation, the oxidized horn keratins have lower cytotoxicity and lower hemolysis ratio. Moreover, when the oxidized horn keratins, as well as different concentration of degradation products of oxidized horn keratins, are directly in contact with platelet-rich plasma, platelets are not activated. It suggests that the oxidized horn keratins have good hemocompatibility, without triggering blood thrombosis. The implantation experiment in vivo also demonstrates that the oxidized horn keratins are compatible with the tissue, because there are minimal fibrous capsule and less of infiltration of host cells, without causing serious inflammation. In summary, the oxidized horn keratins can act as implanted biomaterial devices that are directly in contact with blood and tissue. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Physical Properties of Biological Entities: An Introduction to the Ontology of Physics for Biology

    PubMed Central

    Cook, Daniel L.; Bookstein, Fred L.; Gennari, John H.

    2011-01-01

    As biomedical investigators strive to integrate data and analyses across spatiotemporal scales and biomedical domains, they have recognized the benefits of formalizing languages and terminologies via computational ontologies. Although ontologies for biological entities—molecules, cells, organs—are well-established, there are no principled ontologies of physical properties—energies, volumes, flow rates—of those entities. In this paper, we introduce the Ontology of Physics for Biology (OPB), a reference ontology of classical physics designed for annotating biophysical content of growing repositories of biomedical datasets and analytical models. The OPB's semantic framework, traceable to James Clerk Maxwell, encompasses modern theories of system dynamics and thermodynamics, and is implemented as a computational ontology that references available upper ontologies. In this paper we focus on the OPB classes that are designed for annotating physical properties encoded in biomedical datasets and computational models, and we discuss how the OPB framework will facilitate biomedical knowledge integration. PMID:22216106

  13. Biological glass fibers: Correlation between optical and structural properties

    PubMed Central

    Aizenberg, Joanna; Sundar, Vikram C.; Yablon, Andrew D.; Weaver, James C.; Chen, Gang

    2004-01-01

    Biological systems have, through the course of time, evolved unique solutions for complex optical problems. These solutions are often achieved through a sophisticated control of fine structural features. Here we present a detailed study of the optical properties of basalia spicules from the glass sponge Euplectella aspergillum and reconcile them with structural characteristics. We show these biosilica fibers to have a distinctive layered design with specific compositional variations in the glass/organic composite and a corresponding nonuniform refractive index profile with a high-index core and a low-index cladding. The spicules can function as single-mode, few-mode, or multimode fibers, with spines serving as illumination points along the spicule shaft. The presence of a lens-like structure at the end of the fiber increases its light-collecting efficiency. Although free-space coupling experiments emphasize the similarity of these spicules to commercial optical fibers, the absence of any birefringence, the presence of technologically inaccessible dopants in the fibers, and their improved mechanical properties highlight the advantages of the low-temperature synthesis used by biology to construct these remarkable structures. PMID:14993612

  14. Millimeter wave and terahertz dielectric properties of biological materials

    NASA Astrophysics Data System (ADS)

    Khan, Usman Ansar

    Broadband dielectric properties of materials can be employed to identify, detect, and characterize materials through their unique spectral signatures. In this study, millimeter wave, submillimeter wave, and terahertz dielectric properties of biological substances inclusive of liquids, solids, and powders were obtained using Dispersive Fourier Transform Spectroscopy (DFTS). Two broadband polarizing interferometers were constructed to test materials from 60 GHz to 1.2 THz. This is an extremely difficult portion of the frequency spectrum to obtain a material's dielectric properties since neither optical nor microwave-based techniques provide accurate data. The dielectric characteristics of liquids such as cyclohexane, chlorobenzene, benzene, ethanol, methanol, 1,4 dioxane, and 10% formalin were obtained using the liquid interferometer. Subsequently the solid interferometer was utilized to determine the dielectric properties of human breast tissues, which are fixed and preserved in 10% formalin. This joint collaboration with the Tufts New England Medical Center demonstrated a significant difference between the dielectric response of tumorous and non-tumorous breast tissues across the spectrum. Powders such as anthrax, flour, talc, corn starch, dry milk, and baking soda have been involved in a number of security threats and false alarms around the globe in the last decade. To be able to differentiate hoax attacks and serious security threats, the dielectric properties of common household powders were also examined using the solid interferometer to identify the powders' unique resonance peaks. A new sample preparation kit was designed to test the powder specimens. It was anticipated that millimeter wave and terahertz dielectric characterization will enable one to clearly distinguish one powder from the other; however most of the powders had relatively close dielectric responses and only Talc had a resonance signature recorded at 1.135 THz. Furthermore, due to

  15. Biological Properties of Acidic Cosmetic Water from Seawater

    PubMed Central

    Liao, Wei-Ting; Huang, Tsi-Shu; Chiu, Chien-Chih; Pan, Jian-Liang; Liang, Shih-Shin; Chen, Bing-Hung; Chen, Shi-Hui; Liu, Po-Len; Wang, Hui-Chun; Wen, Zhi-Hong; Wang, Hui-Min; Hsiao, Shu-Wen

    2012-01-01

    This current work was to investigate the biological effects of acidic cosmetic water (ACW) on various biological assays. ACW was isolated from seawater and demonstrated several bio-functions at various concentration ranges. ACW showed a satisfactory effect against Staphylococcus aureus, which reduced 90% of bacterial growth after a 5-second exposure. We used cultured human peripheral blood mononuclear cells (PBMCs) to test the properties of ACW in inflammatory cytokine release, and it did not induce inflammatory cytokine release from un-stimulated, normal PBMCs. However, ACW was able to inhibit bacterial lipopolysaccharide (LPS)-induced inflammatory cytokine TNF-α released from PBMCs, showing an anti-inflammation potential. Furthermore, ACW did not stimulate the rat basophilic leukemia cell (RBL-2H3) related allergy response on de-granulation. Our data presented ACW with a strong anti-oxidative ability in a superoxide anion radical scavenging assay. In mass spectrometry information, magnesium and zinc ions demonstrated bio-functional detections for anti-inflammation as well as other metal ions such as potassium and calcium were observed. ACW also had minor tyrosinase and melanin decreasing activities in human epidermal melanocytes (HEMn-MP) without apparent cytotoxicity. In addition, the cell proliferation assay illustrated anti-growth and anti-migration effects of ACW on human skin melanoma cells (A375.S2) indicating that it exerted the anti-cancer potential against skin cancer. The results obtained from biological assays showed that ACW possessed multiple bioactivities, including anti-microorganism, anti-inflammation, allergy-free, antioxidant, anti-melanin and anticancer properties. To our knowledge, this was the first report presenting these bioactivities on ACW. PMID:22754342

  16. Immunological and biological properties of recombinant Lol p 1.

    PubMed

    Boutin, Y; Lamontagne, P; Boulanger, J; Brunet, C; Hébert, J

    1997-03-01

    Current forms of allergy diagnosis and therapies are based on the use of natural allergenic extracts. Despite strong evidence that higher therapeutic efficacy may be achieved with purified allergens, the purification of multiple allergic components from extracts is a fastidious and sometimes an impossible task. However, the use of recombinant allergens may be an alternative to overcome this problem. In this study, we compared the immunological properties of recombinant (r) Lol p 1 with those of the natural protein. We cloned directly the gene encoding Lol p 1 from genomic DNA of ryegrass pollen. This gene was subcloned into the expression vector pMAL-c and expressed as fusion protein. Subsequently, rLol p 1 was cleaved from maltose-binding protein using factor Xa. Using binding inhibition and proliferative assays, we assessed the immunological properties of the recombinant allergens. The capacity of rLol p 1 to trigger basophil histamine release and to elicit a skin reaction was also assessed and compared to those of its natural counterpart. We found that the Lol p 1 gene has no introns since we amplified this gene directly from genomic DNA. We demonstrated that the binding sites of anti-Lol p 1 monoclonal antibody, specific human IgG and IgE antibody are well conserved on rLol p 1 as no difference in the binding inhibition profile was observed when using either natural or recombinant protein. At the T-cell level, rLol p 1 elicited a T-cell response in mice comparable to that observed with the natural protein. In addition, we demonstrated that the biological characteristics of rLol p 1 were comparable to those of the natural counterpart, in that rLol p 1 elicited a skin wheal reaction and induced basophil histamine release in grass-allergic patients only. The data indicate that natural Lol p 1 and rLol p 1 shared identical immunological and biological properties.

  17. Correlating the morphological and light scattering properties of biological cells

    NASA Astrophysics Data System (ADS)

    Moran, Marina

    The scattered light pattern from a biological cell is greatly influenced by the internal structure and optical properties of the cell. This research project examines the relationships between the morphological and scattering properties of biological cells through numerical simulations. The mains goals are: (1) to develop a procedure to analytically model biological cells, (2) to quantitatively study the effects of a range of cell characteristics on the features of the light scattering patterns, and (3) to classify cells based on the features of their light scattering patterns. A procedure to create an analytical cell model was developed which extracted structural information from the confocal microscopic images of cells and allowed for the alteration of the cell structure in a controlled and systematic way. The influence of cell surface roughness, nuclear size, and mitochondrial volume density, spatial distribution, size and shape on the light scattering patterns was studied through numerical simulations of light scattering using the Discrete Dipole Approximation. It was found that the light scattering intensity in the scattering angle range of 25° to 45° responded to changes in the surface fluctuation of the cell and the range of 90° to 110° was well suited for characterization of mitochondrial density and nuclear size. A comparison of light scattering pattern analysis methods revealed that the angular distribution of the scattered light and Gabor filters were most helpful in differentiating between the cell characteristics. In addition, a measured increase in the Gabor energy of the light scattering patterns in response to an increase in the complexity of the cell models suggested that a complex nuclear structure and mitochondria should be included when modeling biological cells for light scattering simulations. Analysis of the scattering pattern features with Gabor filters resulted in discrimination of the cell models according to cell surface roughness

  18. Biological and therapeutic activities, and anticancer properties of curcumin

    PubMed Central

    PERRONE, DONATELLA; ARDITO, FATIMA; GIANNATEMPO, GIOVANNI; DIOGUARDI, MARIO; TROIANO, GIUSEPPE; LO RUSSO, LUCIO; DE LILLO, ALFREDO; LAINO, LUIGI; LO MUZIO, LORENZO

    2015-01-01

    Curcumin (diferuloylmethane) is a polyphenol derived from the Curcuma longa plant. Curcumin has been used extensively in Ayurvedic medicine, as it is nontoxic and exhibits a variety of therapeutic properties, including antioxidant, analgesic, anti-inflammatory and antiseptic activities. Recently, certain studies have indicated that curcumin may exert anticancer effects in a variety of biological pathways involved in mutagenesis, apoptosis, tumorigenesis, cell cycle regulation and metastasis. The present study reviewed previous studies in the literature, which support the therapeutic activity of curcumin in cancer. In addition, the present study elucidated a number of the challenges concerning the use of curcumin as an adjuvant chemotherapeutic agent. All the studies reviewed herein suggest that curcumin is able to exert anti-inflammatory, antiplatelet, antioxidative, hepatoprotective and antitumor activities, particularly against cancers of the liver, skin, pancreas, prostate, ovary, lung and head neck, as well as having a positive effect in the treatment of arthritis. PMID:26640527

  19. Secondary metabolites and biological properties of Gesneriaceae species.

    PubMed

    Verdan, Maria Helena; Stefanello, Maria Élida Alves

    2012-12-01

    The family Gesneriaceae comprises ca. 150 genera and 3000 species, distributed in the tropics around the world. It is constituted of herbs, lianas, or shrubs, frequently with ornamental potential, due to the beauty of their flowers. Some species have been used in traditional medicine, mainly against fever, cough, colds, snakebite, pains, and infectious and inflammatory diseases. Although Gesneriaceae are a large family, only few species were chemically investigated, and this took place mainly in the last decade. In the present work, chemical and pharmacological studies on Gesneriaceae are reviewed based on original articles published. Altogether 300 compounds have been reported in Gesneriaceae species, including flavonoids, terpenes and steroids, phenolic glucosides, simple phenolics, quinones, lignans, xanthones, and compounds with unusual skeletons. Several species had been used in folk medicine, and some constituents have shown biological activities, such as antimicrobial, anti-inflamatory, antioxidant, and antitumor properties. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.

  20. [Physical, chemical and biological properties of food modified starches].

    PubMed

    Gapparov, M M; Sokolov, A I; Martynova, E A; Kulikova, O S; Bessonov, V V; Berketova, L V

    2007-01-01

    Aim of work was to compare the chemical and biological properties of starches modified by adipinic acid acetylation. Starches in question were: native maize starch "Novation 4600"; acetylated adipat di-starch of the cold swelling "Prejeflo CH 20"; acetylated adipat di-starch of the cold swelling "Prejeflo CH 40"; acetylated adipat di-starch of the hot swelling "Clearam CH 2020". The differences between starches were connected with number of cross-cut lacings in the structure, and with abilities to be gelatinized in the cold water. Rate of hydrolysis and water-retaining capacities were higher for cold swelling starches which contained the smaller number of resistance fractions. Acetyl value of cold swelling starches was higher under elevation of cross-cut lacing.

  1. Menthol: a simple monoterpene with remarkable biological properties.

    PubMed

    Kamatou, Guy P P; Vermaak, Ilze; Viljoen, Alvaro M; Lawrence, Brian M

    2013-12-01

    Menthol is a cyclic monoterpene alcohol which possesses well-known cooling characteristics and a residual minty smell of the oil remnants from which it was obtained. Because of these attributes it is one of the most important flavouring additives besides vanilla and citrus. Due to this reason it is used in a variety of consumer products ranging from confections such as chocolate and chewing gum to oral-care products such as toothpaste as well as in over-the-counter medicinal products for its cooling and biological effects. Its cooling effects are not exclusive to medicinal use. Approximately one quarter of the cigarettes on the market contain menthol and small amounts of menthol are even included in non-mentholated cigarettes. Natural menthol is isolated exclusively from Mentha canadensis, but can also be synthesised on industrial scale through various processes. Although menthol exists in eight stereoisomeric forms, (-)-menthol from the natural source and synthesised menthol with the same structure is the most preferred isomer. The demand for menthol is high and it was previously estimated that the worldwide use of menthol was 30-32,000 metric tonnes per annum. Menthol is not a predominant compound of the essential oils as it can only be found as a constituent of a limited number of aromatic plants. These plants are known to exhibit biological activity in vitro and in vivo such as antibacterial, antifungal, antipruritic, anticancer and analgesic effects, and are also an effective fumigant. In addition, menthol is one of the most effective terpenes used to enhance the dermal penetration of pharmaceuticals. This review summarises the chemical and biological properties of menthol and highlights its cooling effects and toxicity.

  2. Gene duplication and the properties of biological networks.

    PubMed

    Hughes, Austin L; Friedman, Robert

    2005-12-01

    Patterns of network connection of members of multigene families were examined for two biological networks: a genetic network from the yeast Saccharomyces cerevisiae and a protein-protein interaction network from Caenorhabditis elegans. In both networks, genes belonging to gene families represented by a single member in the genome ("singletons") were disproportionately represented among the nodes having large numbers of connections. Of 68 single-member yeast families with 25 or more network connections, 28 (44.4%) were located in duplicated genomic segments believed to have originated from an ancient polyploidization event; thus, each of these 28 loci was thus presumably duplicated along with the genomic segment to which it belongs, but one of the two duplicates has subsequently been deleted. Nodes connected to major "hubs" with a large number of connections, tended to be relatively sparsely interconnected among themselves. Furthermore, duplicated genes, even those arising from recent duplication, rarely shared many network connections, suggesting that network connections are remarkably labile over evolutionary time. These factors serve to explain well-known general properties of biological networks, including their scale-free and modular nature.

  3. Hepatitis B virus genetic variants: biological properties and clinical implications

    PubMed Central

    Tong, Shuping; Li, Jisu; Wands, Jack R; Wen, Yu-mei

    2013-01-01

    Hepatitis B virus (HBV) causes a chronic infection in 350 million people worldwide and greatly increases the risk of liver cirrhosis and hepatocellular carcinoma. The majority of chronic HBV carriers live in Asia. HBV can be divided into eight genotypes with unique geographic distributions. Mutations accumulate during chronic infection or in response to external pressure. Because HBV is an RNA-DNA virus the emergence of drug resistance and vaccine escape mutants has become an important clinical and public health concern. Here, we provide an overview of the molecular biology of the HBV life cycle and an evaluation of the changing role of hepatitis B e antigen (HBeAg) at different stages of infection. The impact of viral genotypes and mutations/deletions in the precore, core promoter, preS, and S gene on the establishment of chronic infection, development of fulminant hepatitis and liver cancer is discussed. Because HBV is prone to mutations, the biological properties of drug-resistant and vaccine escape mutants are also explored. PMID:26038454

  4. Optical characterization of thermal properties of biological tissue

    NASA Astrophysics Data System (ADS)

    Gutierrez-Arroyo, A.; Sánchez Pérez, C.; Alemán-García, N.; Piña-Barba, C.

    2013-11-01

    In this work we utilize heat conduction measurements trough the photothermal beam deflection technique to characterize thermal properties of biological tissue. We design a heat flux sensor based on the phenomenon of photothermal laser beam deflection within a thermo-optic slab (acrylic), where the deflection is quantified by an optical fiber angle sensor. We analytically model the heat flux sensor response based on heat wave propagation theory that well agree with experimental data. We present heat conduction measurements on different tissues applying a heat pulse. Hence we obtain the thermal effusivity coefficient of bovine tendon and chicken liver and heart. It has been shown that thermal conduction depends on the tissués chemical composition as well on their structural arrangements, so any modification in tissue will affect on heat conduction rendering this method potentially useful as an auxiliary in biomedical studies. Nowadays there are several thermal effusivity and diffusivity measurement techniques with classic calorimetry (using thermistors) for research and industrial applications. However there are only few integrated optical devices already proposed, turning this optical technique in an innovative and alternative sensing system for thermal properties characterization.

  5. Autologous chondrocyte implantation: superior biologic properties of hyaline cartilage repairs.

    PubMed

    Henderson, Ian; Lavigne, Patrick; Valenzuela, Herminio; Oakes, Barry

    2007-02-01

    Information regarding the quality of autologous chondrocyte implantation repair is needed to determine whether the current autologous chondrocyte implantation surgical technology and the subsequent biologic repair processes are capable of reliably forming durable hyaline or hyaline-like cartilage in vivo. We report and analyze the properties and qualities of autologous chondrocyte implantation repairs. We evaluated 66 autologous chondrocyte implantation repairs in 57 patients, 55 of whom had histology, indentometry, and International Cartilage Repair Society repair scoring at reoperation for mechanical symptoms or pain. International Knee Documentation Committee scores were used to address clinical outcome. Maximum stiffness, normalized stiffness, and International Cartilage Repair Society repair scoring were higher for hyaline articular cartilage repairs compared with fibrocartilage, with no difference in clinical outcome. Reoperations revealed 32 macroscopically abnormal repairs (Group B) and 23 knees with normal-looking repairs in which symptoms leading to arthroscopy were accounted for by other joint disorders (Group A). In Group A, 65% of repairs were either hyaline or hyaline-like cartilage compared with 28% in Group B. Autologous chondrocyte repairs composed of fibrocartilage showed more morphologic abnormalities and became symptomatic earlier than hyaline or hyaline-like cartilage repairs. The hyaline articular cartilage repairs had biomechanical properties comparable to surrounding cartilage and superior to those associated with fibrocartilage repairs.

  6. Biological and therapeutic properties of bee pollen: a review.

    PubMed

    Denisow, Bożena; Denisow-Pietrzyk, Marta

    2016-10-01

    Natural products, including bee products, are particularly appreciated by consumers and are used for therapeutic purposes as alternative drugs. However, it is not known whether treatments with bee products are safe and how to minimise the health risks of such products. Among others, bee pollen is a natural honeybee product promoted as a valuable source of nourishing substances and energy. The health-enhancing value of bee pollen is expected due to the wide range of secondary plant metabolites (tocopherol, niacin, thiamine, biotin and folic acid, polyphenols, carotenoid pigments, phytosterols), besides enzymes and co-enzymes, contained in bee pollen. The promising reports on the antioxidant, anti-inflammatory, anticariogenic antibacterial, antifungicidal, hepatoprotective, anti-atherosclerotic, immune enhancing potential require long-term and large cohort clinical studies. The main difficulty in the application of bee pollen in modern phytomedicine is related to the wide species-specific variation in its composition. Therefore, the variations may differently contribute to bee-pollen properties and biological activity and thus in therapeutic effects. In principle, we can unequivocally recommend bee pollen as a valuable dietary supplement. Although the bee-pollen components have potential bioactive and therapeutic properties, extensive research is required before bee pollen can be used in therapy. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  7. Biologic properties of surgical scaffold materials derived from dermal ECM.

    PubMed

    Kulig, Katherine M; Luo, Xiao; Finkelstein, Eric B; Liu, Xiang-Hong; Goldman, Scott M; Sundback, Cathryn A; Vacanti, Joseph P; Neville, Craig M

    2013-07-01

    Surgical scaffold materials manufactured from donor human or animal tissue are increasingly being used to promote soft tissue repair and regeneration. The clinical product consists of the residual extracellular matrix remaining after a rigorous decellularization process. Optimally, the material provides both structural support during the repair period and cell guidance cues for effective incorporation into the regenerating tissue. Surgical scaffold materials are available from several companies and are unique products manufactured by proprietary methodology. A significant need exists for a more thorough understanding of scaffold properties that impact the early steps of host cell recruitment and infiltration. In this study, a panel of in vitro assays was used to make direct comparisons of several similar, commercially-available materials: Alloderm, Medeor Matrix, Permacol, and Strattice. Differences in the materials were detected for both cell signaling and scaffold architecture-dependent cell invasion. Material-conditioned media studies found Medeor Matrix to have the greatest positive effect upon cell proliferation and induction of migration. Strattice provided the greatest chemotaxis signaling and best suppressed apoptotic induction. Among assays measuring structure-dependent properties, Medeor Matrix was superior for cell attachment, followed by Permacol. Only Alloderm and Medeor Matrix supported chemotaxis-driven cell invasion beyond the most superficial zone. Medeor Matrix was the only material in the chorioallantoic membrane assay to support substantial cell invasion. These results indicate that both biologic and structural properties need to be carefully assessed in the considerable ongoing efforts to develop new uses and products in this important class of biomaterials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Inverse Algorithm Optimization for Determining Optical Properties of Biological Materials from Spatially-Resolved Diffuse Reflectance

    USDA-ARS?s Scientific Manuscript database

    Optical characterization of biological materials is useful in many scientific and industrial applications like biomedical diagnosis and nondestructive quality evaluation of food and agricultural products. However, accurate determination of the optical properties from intact biological materials base...

  9. Plant polyphenols: chemical properties, biological activities, and synthesis.

    PubMed

    Quideau, Stéphane; Deffieux, Denis; Douat-Casassus, Céline; Pouységu, Laurent

    2011-01-17

    Eating five servings of fruits and vegetables per day! This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why? The answer is in fact still under scientific scrutiny, but a particular class of compounds naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really? What are their physicochemical properties? How do they express their biological activity? Are they really valuable for disease prevention? Can they be used to develop new pharmaceutical drugs? What recent progress has been made toward their preparation by organic synthesis? This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Impact of temperature on the biological properties of soil

    NASA Astrophysics Data System (ADS)

    Borowik, Agata; Wyszkowska, Jadwiga

    2016-01-01

    The aim of the study was to determine the response of soil microorganisms and enzymes to the temperature of soil. The effect of the temperatures: 5, 10, 15, 20, and 25°C on the biological properties of soil was investigated under laboratory conditions. The study was performed using four different soils differing in their granulometric composition. It was found that 15°C was the optimal temperature for the development of microorganisms in soil. Typically, in the soil, the highest activity of dehydrogenases was observed at 10-15°C, catalase and acid phosphatase - at 15°C, alkaline phosphatase at 20°C, urease and β-glucosidase at 25°C. The highest colony development index for heterotrophic bacteria was recorded in soils incubated at 25°C, while for actinomycetes and fungi at 15°C. The incubation temperature of soil only slightly changed the ecophysiological variety of the investigated groups of microorganisms. Therefore, the observed climate changes might have a limited impact on the soil microbiological activity, because of the high ability of microorganisms to adopt. The response of soil microorganisms and enzymes was more dependent on the soil granulometric composition, organic carbon, and total nitrogen than on its temperature.

  11. Essential oils from neotropical Myrtaceae: chemical diversity and biological properties.

    PubMed

    Stefanello, Maria Élida Alves; Pascoal, Aislan C R F; Salvador, Marcos J

    2011-01-01

    Myrtaceae family (121 genera, 3800-5800 spp.) is one of the most important families in tropical forests. They are aromatic trees or shrubs, which frequently produce edible fruits. In the neotropics, ca. 1000 species were found. Several members of this family are used in folk medicine, mainly as an antidiarrheal, antimicrobial, antioxidant, cleanser, antirheumatic, and anti-inflammatory agent and to decrease the blood cholesterol. In addition, some fruits are eaten fresh or used to make juices, liqueurs, and sweets very much appreciated by people. The flavor composition of some fruits belonging to the Myrtaceae family has been extensively studied due to their pleasant and intense aromas. Most of the essential oils of neotropical Myrtaceae analyzed so far are characterized by predominance of sesquiterpenes, some with important biological properties. In the present work, chemical and pharmacological studies carried out on neotropical Myrtaceae species are reviewed, based on original articles published since 1980. The uses in folk medicine and chemotaxonomic importance of secondary metabolites are also briefly discussed. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich.

  12. Some biological properties of respirable iron ore dust.

    PubMed

    Keast, D; Sheppard, N P; Papadimitriou, J M

    1987-04-01

    The respirable fraction of an ore dust from the North-West of Western Australia was tested for biological properties by inhalation and intrapleural implantation trials using rats and mice. Pulmonary histology indicated significant levels of interstitial pneumonia occasionally associated with bronchopneumonia, bronchiectasis, emphysema, and lung collapse over that found in age-matched control animals. While there was a significant increase of the incidence of tumors in general in WAG inbred rats up to 2 years following dust exposure, this did not persist into old age. No mesotheliomas were induced by any treatments associated with iron ore dust, although the rats were shown to be susceptible to crocidolite asbestos-induced mesothelioma. In the mouse models, tumors which are normally seen only in aged animals were induced with a significant number of bronchial adenomas being recorded following intrapleural implantation of dust into inbred BALB/c mice. Leukemia/lymphoma associated with murine leukemia virus was increased following dust inhalation by inbred C57BL mice.

  13. Biochemical characteristics and biological properties of Annurca apple cider.

    PubMed

    Fratianni, Florinda; De Giulio, Alfonso; Sada, Alfonso; Nazzaro, Filomena

    2012-01-01

    Our work aimed to investigate the phenolic composition and antioxidant capacity of the de-alcoholized extract of cider obtained from the Annurca apple (Malus domestica var. Annurca). The antimicrobial effect of the extract against different pathogens, including Chronobacter sakazakii, was also examined. The extract's potential anti-quorum-sensing (AQS) activity was assessed using the test microorganism Chromobacterium violaceum. Biochemical analysis of the extract using ultra-performance liquid chromatography revealed catechin and caffeic acid as the most abundant polyphenols present, which represented about 35.5% and 36.6% of the total phenolics identified, respectively. An antioxidant capacity was also found (50% effective concentraiton=10 μL). The extract exhibited clear antimicrobial activity against all strains used in the experiments. Escherichia coli and Bacillus cereus were the most sensitive bacteria to the antimicrobial activity. The extract also inhibited the growth of the emergent pathogen strain C. sakazakii. The AQS activity of apple cider is reported here for the first time. In conclusion, our results demonstrate some biological properties of the apple cider and contribute to reinforcing the potential of the apple and its derivatives as functional components of the diet.

  14. Chemical, biological, and immunochemical properties of the Chlamydia psittaci lipopolysaccharide.

    PubMed Central

    Brade, L; Schramek, S; Schade, U; Brade, H

    1986-01-01

    The lipopolysaccharide (LPS) of Chlamydia psittaci was extracted from yolk sac-grown elementary bodies, purified, and characterized chemically, immunochemically, and biologically. The LPS contained D-galactosamine, D-glucosamine, phosphorus, long-chain fatty acids, and 3-deoxy-D-manno-2-octulosonic acid in the molar ratio of approximately 1:2:2:6:5. The antigenic properties of the isolated LPS were compared with those of the LPS from Chlamydia trachomatis and Salmonella minnesota Re by the passive hemolysis and passive hemolysis inhibition tests, absorption, hydrolysis kinetics, and Western blot analysis with rabbit polyclonal antisera against chlamydiae and with a mouse monoclonal antibody recognizing a genus-specific epitope of chlamydial LPS. Two antigenic determinants were identified, one of which was chlamydia specific and the other of which was cross-reactive with Re LPS. Both determinants were destroyed during acid hydrolysis, whereby a third antigen specificity was exposed which was indistinguishable from the lipid A antigenicity. In rabbit polyclonal antisera prepared against Formalin-killed elementary bodies or detergent-solubilized membranes, two antibody specificities were differentiated. One of these was chlamydia specific, and the other was cross-reactive with Re LPS. The LPS of C. psittaci was inactive within typical endotoxin parameters (lethal toxicity, pyrogenicity, local Shwartzman reactivity); it was, however, active in some in vitro assays, such as those testing for mouse B-cell mitogenicity and the induction of prostaglandin E2 in mouse peritoneal macrophages. Images PMID:3770953

  15. H5N1 influenza viruses: outbreaks and biological properties

    PubMed Central

    Neumann, Gabriele; Chen, Hualan; Gao, George F; Shu, Yuelong; Kawaoka, Yoshihiro

    2010-01-01

    All known subtypes of influenza A viruses are maintained in wild waterfowl, the natural reservoir of these viruses. Influenza A viruses are isolated from a variety of animal species with varying morbidity and mortality rates. More importantly, influenza A viruses cause respiratory disease in humans with potentially fatal outcome. Local or global outbreaks in humans are typically characterized by excess hospitalizations and deaths. In 1997, highly pathogenic avian influenza viruses of the H5N1 subtype emerged in Hong Kong that transmitted to humans, resulting in the first documented cases of human death by avian influenza virus infection. A new outbreak started in July 2003 in poultry in Vietnam, Indonesia, and Thailand, and highly pathogenic avian H5N1 influenza viruses have since spread throughout Asia and into Europe and Africa. These viruses continue to infect humans with a high mortality rate and cause worldwide concern of a looming pandemic. Moreover, H5N1 virus outbreaks have had devastating effects on the poultry industries throughout Asia. Since H5N1 virus outbreaks appear to originate from Southern China, we here examine H5N1 influenza viruses in China, with an emphasis on their biological properties. PMID:19884910

  16. Dynamic properties of biologically active synthetic heparin-like hexasaccharides.

    PubMed

    Angulo, Jesús; Hricovíni, Milos; Gairi, Margarida; Guerrini, Marco; de Paz, José Luis; Ojeda, Rafael; Martín-Lomas, Manuel; Nieto, Pedro M

    2005-10-01

    A complete study of the dynamics of two synthetic heparin-like hexasaccharides, D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-1-->iPr (1) and -->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHAc-6-SO4-alpha-(1-->4)-L-IdoA-alpha-(1-->4)-D-GlcNHSO3-alpha-(1-->4)-L-IdoA-2-SO4-alpha-1-->iPr (2), has been performed using 13C-nuclear magnetic resonance (NMR) relaxation parameters, T1, T2, and heteronuclear nuclear Overhauser effect (NOEs). Compound 1 is constituted from sequences corresponding to the major polysaccharide heparin region, while compound 2 contains a sequence never found in natural heparin. They differ from each other only in sulphation patterns, and are capable of stimulating fibroblast growth factors (FGFs)-1 induced mitogenesis. Both oligosaccharides exhibit a remarkable anisotropic overall motion in solution as revealed by their anisotropic ratios (tau /tau||), 4.0 and 3.0 respectively. This is a characteristic behaviour of natural glycosaminoglycans (GAG) which has also been observed for the antithrombin (AT) binding pentasaccharide D-GlcNHSO3-6-SO4-alpha-(1-->4)-D-GlcA-beta-(1-->4)-D-GlcNHSO3-(3,6-SO4)-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-1-->Me (3) (Hricovíni, M., Guerrini, M., Torri, G., Piani, S., and Ungarelli, F. (1995) Conformational analysis of heparin epoxide in aqueous solution. An NMR relaxation study. Carbohydr. Res., 277, 11-23). The motional properties observed for 1 and 2 provide additional support to the suitability of these compounds as heparin models in agreement with previous structural (de Paz, J.L., Angulo, J., Lassaletta, J.M., Nieto, P.M., Redondo-Horcajo, M., Lozano, R.M., Jiménez-Gallego, G., and Martín-Lomas, M. (2001) The activation of fibroblast growth factors by heparin: synthesis, structure and biological activity of heparin-like oligosaccharides. Chembiochem, 2, 673-685; Ojeda, R

  17. Emerging Differentiation of Folkbiology and Folkpsychology: Attributions of Biological and Psychological Properties to Living Things.

    ERIC Educational Resources Information Center

    Coley, John D.

    1995-01-01

    Examined whether children differentiate or confuse the domains of folk biology and folk psychology. Children and adult subjects were asked whether the animals depicted in pictures possessed certain biological and psychological properties. Results indicated that by kindergarten, notions of folk psychology and folk biology are sufficiently…

  18. Preparation, characterization and biological properties of biotinylated derivatives of calmodulin.

    PubMed Central

    Polli, J W; Billingsley, M L

    1991-01-01

    Biotinylated derivatives of calmodulin (CaM) were prepared and their biological properties characterized by using enzyme assays, affinity and hydrophobic-interaction chromatography. Several N-hydroxysuccinimidobiotin derivatives [sulphosuccinimidobiotin (sulpho-NHS) and sulphosuccinimido-6-(biotinamido)hexanoate (BNHS-LC)] differing in spacer arm length were used to modify CaM. The shorter-spacer-arm CaM derivative (sulpho-CaM) activated CaM-dependent cyclic nucleotide phosphodiesterase and CaM-dependent protein kinase II; preincubation with avidin blocked its ability to activate these enzymes. The extended-spacer-arm derivative (BNHS-LC-CaM) activated CaM-dependent enzymes both in the presence and in the absence of avidin, suggesting that the longer spacer arm diminished steric effects from avidin preincubation. Other biotinylated CaM derivatives were prepared with biotinylated tyrosine and/or histidine residues (diazobenzoylbiocytin; DBB-CaM) or nucleophilic sites (photobiotin acetate; photo-CaM). These derivatives activated CaM-dependent enzymes in the presence and in the absence of avidin. Oriented affinity columns were constructed with covalently immobilized avidin complexed to each biotinylated CaM derivative. The chromatographic profiles obtained revealed that each column interacted with a specific subset of CaM-binding proteins. Elution profiles of biotinyl CaM derivatives on phenyl-Sepharose hydrophobic-interaction chromatography suggested that several derivatives displayed diminished binding to the matrix in the presence of Ca2+. Development and characterization of a series of biotinylated CaM molecules can be used to identify domains of CaM that interact with specific CaM-dependent enzymes. Images Fig. 1. Fig. 4. Fig. 6. Fig. 7. PMID:1645521

  19. Preparation, characterization and biological properties of biotinylated derivatives of calmodulin.

    PubMed

    Polli, J W; Billingsley, M L

    1991-05-01

    Biotinylated derivatives of calmodulin (CaM) were prepared and their biological properties characterized by using enzyme assays, affinity and hydrophobic-interaction chromatography. Several N-hydroxysuccinimidobiotin derivatives [sulphosuccinimidobiotin (sulpho-NHS) and sulphosuccinimido-6-(biotinamido)hexanoate (BNHS-LC)] differing in spacer arm length were used to modify CaM. The shorter-spacer-arm CaM derivative (sulpho-CaM) activated CaM-dependent cyclic nucleotide phosphodiesterase and CaM-dependent protein kinase II; preincubation with avidin blocked its ability to activate these enzymes. The extended-spacer-arm derivative (BNHS-LC-CaM) activated CaM-dependent enzymes both in the presence and in the absence of avidin, suggesting that the longer spacer arm diminished steric effects from avidin preincubation. Other biotinylated CaM derivatives were prepared with biotinylated tyrosine and/or histidine residues (diazobenzoylbiocytin; DBB-CaM) or nucleophilic sites (photobiotin acetate; photo-CaM). These derivatives activated CaM-dependent enzymes in the presence and in the absence of avidin. Oriented affinity columns were constructed with covalently immobilized avidin complexed to each biotinylated CaM derivative. The chromatographic profiles obtained revealed that each column interacted with a specific subset of CaM-binding proteins. Elution profiles of biotinyl CaM derivatives on phenyl-Sepharose hydrophobic-interaction chromatography suggested that several derivatives displayed diminished binding to the matrix in the presence of Ca2+. Development and characterization of a series of biotinylated CaM molecules can be used to identify domains of CaM that interact with specific CaM-dependent enzymes.

  20. Body and Soul: Do Children Distinguish between Foods When Generalizing Biological and Psychological Properties?

    ERIC Educational Resources Information Center

    Thibaut, Jean-Pierre; Nguyen, Simone P.; Murphy, Gregory L.

    2016-01-01

    Research Findings: In 2 experiments, we tested whether children generalize psychological and biological properties to novel foods. We used an induction task in which a property (either biological or psychological) was associated with a target food. Children were then asked whether a taxonomically related and a script-related food would also have…

  1. Body and Soul: Do Children Distinguish between Foods When Generalizing Biological and Psychological Properties?

    ERIC Educational Resources Information Center

    Thibaut, Jean-Pierre; Nguyen, Simone P.; Murphy, Gregory L.

    2016-01-01

    Research Findings: In 2 experiments, we tested whether children generalize psychological and biological properties to novel foods. We used an induction task in which a property (either biological or psychological) was associated with a target food. Children were then asked whether a taxonomically related and a script-related food would also have…

  2. Mechanical properties of the beetle elytron, a biological composite material

    USDA-ARS?s Scientific Manuscript database

    We determined the relationship between composition and mechanical properties of elytral (modified forewing) cuticle of the beetles Tribolium castaneum and Tenebrio molitor. Elytra of both species have similar mechanical properties at comparable stages of maturation (tanning). Shortly after adult ecl...

  3. Optical properties and cross-sections of biological aerosols

    NASA Astrophysics Data System (ADS)

    Thrush, E.; Brown, D. M.; Salciccioli, N.; Gomes, J.; Brown, A.; Siegrist, K.; Thomas, M. E.; Boggs, N. T.; Carter, C. C.

    2010-04-01

    There is an urgent need to develop standoff sensing of biological agents in aerosolized clouds. In support of the Joint Biological Standoff Detection System (JBSDS) program, lidar systems have been a dominant technology and have shown significant capability in field tests conducted in the Joint Ambient Breeze Tunnel (JABT) at Dugway Proving Ground (DPG). The release of biological agents in the open air is forbidden. Therefore, indirect methods must be developed to determine agent cross-sections in order to validate sensor against biological agents. A method has been developed that begins with laboratory measurements of thin films and liquid suspensions of biological material to obtain the complex index of refraction from the ultraviolet (UV) to the long wave infrared (LWIR). Using that result and the aerosols' particle size distribution as inputs to Mie calculations yields the backscatter and extinction cross-sections as a function of wavelength. Recent efforts to model field measurements from the UV to the IR have been successful. Measurements with aerodynamic and geometric particle sizers show evidence of particle clustering. Backscatter simulations of these aerosols show these clustered particles dominate the aerosol backscatter and depolarization signals. In addition, these large particles create spectral signatures in the backscatter signal due to material absorption. Spectral signatures from the UV to the IR have been observed in simulations of field releases. This method has been demonstrated for a variety of biological simulant materials such as Ovalbumin (OV), Erwinia (EH), Bacillus atrophaeus (BG) and male specific bacteriophage (MS2). These spectral signatures may offer new methods for biological discrimination for both stand-off sensing and point detection systems.

  4. Properties of Biological Media Determined from Polarization Properties of Backscattered Light

    NASA Astrophysics Data System (ADS)

    Locke, Landon

    2004-04-01

    Optical tissue characterization (OTC) is a biomedical optical technique that can potentially be useful in diagnosing and monitoring physiological changes in tissue without surgical intervention. OTC is a rapid, inexpensive, and non-invasive technique that may one day eliminate the occurrence of unnecessary biopsies. By directing light of various known polarization states onto a biological sample and analyzing the polarization state of the backscattered light, it is possible to extract quantitative information about the biological medium. The backscattering can be parameterized by the Mueller matrix, some elements of which are already known to be sensitive to particular properties of the scattering medium. For example, one known matrix element is related to the average size of the scatterers (A. H. Hielscher, A. A. Eick, et al.). There are, however, many elements of the Mueller matrix that have not been studied. My research interests lie in investigating what information some of the other elements of the Mueller matrix are capable of providing. I have constructed an apparatus to experimentally determine Mueller matrices for various samples. I will describe the method and present results to date.

  5. An ab-initio Computational Method to Determine Dielectric Properties of Biological Materials

    PubMed Central

    Abeyrathne, Chathurika D.; Halgamuge, Malka N.; Farrell, Peter M.; Skafidas, Efstratios

    2013-01-01

    Frequency dependent dielectric properties are important for understanding the structure and dynamics of biological materials. These properties can be used to study underlying biological processes such as changes in the concentration of biological materials, and the formation of chemical species. Computer simulations can be used to determine dielectric properties and atomic details inaccessible via experimental methods. In this paper, a unified theory utilizing molecular dynamics and density functional theory is presented that is able to determine the frequency dependent dielectric properties of biological materials in an aqueous solution from their molecular structure alone. The proposed method, which uses reaction field approximations, does not require a prior knowledge of the static dielectric constant of the material. The dielectric properties obtained from our method agree well with experimental values presented in the literature. PMID:23652459

  6. An ontology on property for physical, chemical, and biological systems.

    PubMed

    Dybkaer, René

    2004-01-01

    Current metrological literature, including the International vocabulary of basic and general terms in metrology (VIM 1993), presents a special language slowly evolved without consistent use of the procedures of terminological work; furthermore, nominal properties are excluded by definition. Both deficiencies create problems in fields, such as laboratory medicine, which have to report results of all types of property, preferably in a unified systematic format. The present text aims at forming a domain ontology around "property", with intensional definitions and systematic terms, mainly using the terminological tools--with some additions--provided by the International Standards ISO 704, 1087-1, and 10241. "System" and "component" are defined, "quantity" is discussed, and the generic concept "property" is given as 'inherent state- or process-descriptive feature of a system including any pertinent components'. Previously, the term 'kind-of-quantity' and quasi-synonyms have been used as primitives; the proposed definition of "kind-of-property" is 'common defining aspect of mutually comparable properties'. "Examination procedure", "examination method", "examination principle", and "examination" are defined, avoiding the term 'test'. The need to distinguish between instances of "characteristic", "property", "type of characteristic", "kind-of-property", and "property value" is emphasized; the latter is defined together with "property value scale". These fundamental concepts are presented in a diagram, and the effect of adding essential characteristics to give expanded definitions is exemplified. Substitution usually leads to unwieldy definitions, but reveals circularity as does exhaustive consecutive listing of defining concepts. The top concept <property> may be generically divided according to many terminological dimensions, especially regarding which operators are allowed among the four sets =, not equal to; <, >; +, -; and x, :. The coordinate concepts defined are

  7. Predictive Models of Nanotoxicity: Relationship of Physicochemical Properties to Particle Movement Through Biological Barriers

    EPA Science Inventory

    Understanding the linkage between the physicochemical (PC) properties of nanoparticles (NP) and their activation of biological systems is poorly understood, yet fundamental to predicting nanotoxicity, idenitifying mode of actions and developing appropriate and effective regul...

  8. Predictive Models of Nanotoxicity: Relationship of Physicochemical Properties to Particle Movement Through Biological Barriers

    EPA Science Inventory

    Understanding the linkage between the physicochemical (PC) properties of nanoparticles (NP) and their activation of biological systems is poorly understood, yet fundamental to predicting nanotoxicity, idenitifying mode of actions and developing appropriate and effective regul...

  9. Essential Oils of Oregano: Biological Activity beyond Their Antimicrobial Properties.

    PubMed

    Leyva-López, Nayely; Gutiérrez-Grijalva, Erick P; Vazquez-Olivo, Gabriela; Heredia, J Basilio

    2017-06-14

    Essential oils of oregano are widely recognized for their antimicrobial activity, as well as their antiviral and antifungal properties. Nevertheless, recent investigations have demonstrated that these compounds are also potent antioxidant, anti-inflammatory, antidiabetic and cancer suppressor agents. These properties of oregano essential oils are of potential interest to the food, cosmetic and pharmaceutical industries. The aim of this manuscript is to review the latest evidence regarding essential oils of oregano and their beneficial effects on health.

  10. Marine sponge lectins: actual status on properties and biological activities.

    PubMed

    Gomes Filho, Sandro Mascena; Cardoso, Juscélio Donizete; Anaya, Katya; Silva do Nascimento, Edilza; de Lacerda, José Thalles Jucelino Gomes; Mioso, Roberto; Santi Gadelha, Tatiane; de Almeida Gadelha, Carlos Alberto

    2014-12-26

    Marine sponges are primitive metazoans that produce a wide variety of molecules that protect them against predators. In studies that search for bioactive molecules, these marine invertebrates stand out as promising sources of new biologically-active molecules, many of which are still unknown or little studied; thus being an unexplored biotechnological resource of high added value. Among these molecules, lectins are proteins that reversibly bind to carbohydrates without modifying them. In this review, various structural features and biological activities of lectins derived from marine sponges so far described in the scientific literature are discussed. From the results found in the literature, it could be concluded that lectins derived from marine sponges are structurally diverse proteins with great potential for application in the production of biopharmaceuticals, especially as antibacterial and antitumor agents.

  11. Biological properties of 6-gingerol: a brief review.

    PubMed

    Wang, Shaopeng; Zhang, Caihua; Yang, Guang; Yang, Yanzong

    2014-07-01

    Numerous studies have revealed that regular consumption of certain fruits and vegetables can reduce the risk of many diseases. The rhizome of Zingiber officinale (ginger) is consumed worldwide as a spice and herbal medicine. It contains pungent phenolic substances collectively known as gingerols. 6-Gingerol is the major pharmacologically-active component of ginger. It is known to exhibit a variety of biological activities including anticancer, anti-inflammation, and anti-oxidation. 6-Gingerol has been found to possess anticancer activities via its effect on a variety of biological pathways involved in apoptosis, cell cycle regulation, cytotoxic activity, and inhibition of angiogenesis. Thus, due to its efficacy and regulation of multiple targets, as well as its safety for human use, 6-gingerol has received considerable interest as a potential therapeutic agent for the prevention and/or treatment of various diseases. Taken together, this review summarizes the various in vitro and in vivo pharmacological aspects of 6-gingerol and the underlying mechanisms.

  12. Multiple biological properties of macelignan and its pharmacological implications.

    PubMed

    Paul, Saswati; Hwang, Jae Kwan; Kim, Hahn Young; Jeon, Won Kyung; Chung, ChiHye; Han, Jung-Soo

    2013-03-01

    Macelignan found in the nutmeg mace of Myristica fragrans obtains increasing attention as a new avenue in treating various diseases. Macelignan has been shown to possess a spectrum of pharmacological activities, including anti-bacterial, anti-inflammatory, anti-cancer, anti-diabetes, and hepatoprotective activities; recently, it has also been shown to have neuroprotective activities. This review summarizes the current research on the biological effects of macelignan derived from M. fragrans, with emphasis on the importance in understanding and treating complex diseases such as cancer and Alzheimer's disease.

  13. Biological properties of extracellular vesicles and their physiological functions

    PubMed Central

    Yáñez-Mó, María; Siljander, Pia R.-M.; Andreu, Zoraida; Zavec, Apolonija Bedina; Borràs, Francesc E.; Buzas, Edit I.; Buzas, Krisztina; Casal, Enriqueta; Cappello, Francesco; Carvalho, Joana; Colás, Eva; Silva, Anabela Cordeiro-da; Fais, Stefano; Falcon-Perez, Juan M.; Ghobrial, Irene M.; Giebel, Bernd; Gimona, Mario; Graner, Michael; Gursel, Ihsan; Gursel, Mayda; Heegaard, Niels H. H.; Hendrix, An; Kierulf, Peter; Kokubun, Katsutoshi; Kosanovic, Maja; Kralj-Iglic, Veronika; Krämer-Albers, Eva-Maria; Laitinen, Saara; Lässer, Cecilia; Lener, Thomas; Ligeti, Erzsébet; Linē, Aija; Lipps, Georg; Llorente, Alicia; Lötvall, Jan; Manček-Keber, Mateja; Marcilla, Antonio; Mittelbrunn, Maria; Nazarenko, Irina; Hoen, Esther N.M. Nolte-‘t; Nyman, Tuula A.; O'Driscoll, Lorraine; Olivan, Mireia; Oliveira, Carla; Pállinger, Éva; del Portillo, Hernando A.; Reventós, Jaume; Rigau, Marina; Rohde, Eva; Sammar, Marei; Sánchez-Madrid, Francisco; Santarém, N.; Schallmoser, Katharina; Ostenfeld, Marie Stampe; Stoorvogel, Willem; Stukelj, Roman; Van der Grein, Susanne G.; Vasconcelos, M. Helena; Wauben, Marca H. M.; De Wever, Olivier

    2015-01-01

    In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system. PMID:25979354

  14. Biological properties of extracellular vesicles and their physiological functions.

    PubMed

    Yáñez-Mó, María; Siljander, Pia R-M; Andreu, Zoraida; Zavec, Apolonija Bedina; Borràs, Francesc E; Buzas, Edit I; Buzas, Krisztina; Casal, Enriqueta; Cappello, Francesco; Carvalho, Joana; Colás, Eva; Cordeiro-da Silva, Anabela; Fais, Stefano; Falcon-Perez, Juan M; Ghobrial, Irene M; Giebel, Bernd; Gimona, Mario; Graner, Michael; Gursel, Ihsan; Gursel, Mayda; Heegaard, Niels H H; Hendrix, An; Kierulf, Peter; Kokubun, Katsutoshi; Kosanovic, Maja; Kralj-Iglic, Veronika; Krämer-Albers, Eva-Maria; Laitinen, Saara; Lässer, Cecilia; Lener, Thomas; Ligeti, Erzsébet; Linē, Aija; Lipps, Georg; Llorente, Alicia; Lötvall, Jan; Manček-Keber, Mateja; Marcilla, Antonio; Mittelbrunn, Maria; Nazarenko, Irina; Nolte-'t Hoen, Esther N M; Nyman, Tuula A; O'Driscoll, Lorraine; Olivan, Mireia; Oliveira, Carla; Pállinger, Éva; Del Portillo, Hernando A; Reventós, Jaume; Rigau, Marina; Rohde, Eva; Sammar, Marei; Sánchez-Madrid, Francisco; Santarém, N; Schallmoser, Katharina; Ostenfeld, Marie Stampe; Stoorvogel, Willem; Stukelj, Roman; Van der Grein, Susanne G; Vasconcelos, M Helena; Wauben, Marca H M; De Wever, Olivier

    2015-01-01

    In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.

  15. Synthesis and biological properties of amino acids and peptides containing a tetrazolyl moiety

    NASA Astrophysics Data System (ADS)

    Popova, E. A.; Trifonov, R. E.

    2015-09-01

    Literature data published mainly in the last 15 years on the synthesis and biological properties of amino acid analogues and derivatives containing tetrazolyl moieties are analyzed. Tetrazolyl analogues and derivatives of amino acids and peptides are shown to be promising for medicinal chemistry. Being polynitrogen heterocyclic systems comprising four endocyclic nitrogen atoms, tetrazoles can behave as acids and bases and form strong hydrogen bonds with proton donors (more rarely, with acceptors). They have high metabolic stability and are able to penetrate biological membranes. The review also considers the synthesis and properties of linear and cyclic peptides based on modified amino acids incorporating a tetrazolyl moiety. A special issue is the discussion of the biological properties of tetrazole-containing amino acids and peptides, which exhibit high biological activity and can be used to design new drugs. The bibliography includes 200 references.

  16. Optimization of spatial frequency domain imaging technique for estimating optical properties of food and biological materials

    USDA-ARS?s Scientific Manuscript database

    Spatial frequency domain imaging technique has recently been developed for determination of the optical properties of food and biological materials. However, accurate estimation of the optical property parameters by the technique is challenging due to measurement errors associated with signal acquis...

  17. Biological properties of garlic and garlic-derived organosulfur compounds.

    PubMed

    Iciek, Małgorzata; Kwiecień, Inga; Włodek, Lidia

    2009-04-01

    Medicinal properties of garlic (Allium sativum) have been widely known and used since ancient times till the present. Garlic enhances immune functions and has antibacterial, antifungal and antivirus activities. It is known to prevent platelet aggregation, and to have hypotensive and cholesterol- and triglyceride-lowering properties, although the latter features have been questioned. This review is focused on anticancer efficacy of Allium sativum, and attempts to explain the mechanisms of this action. Medicinal properties of garlic rely upon organosulfur compounds mostly derived from alliin. Organosulfur compounds originating from garlic inhibit carcinogen activation, boost phase 2 detoxifying processes, cause cell cycle arrest mostly in G2/M phase, stimulate the mitochondrial apoptotic pathway, increase acetylation of histones. Garlic-derived sulfur compounds influence also gap-junctional intercellular communication and participate in the development of multidrug resistance. This review presents also other little known aspects of molecular action of garlic-derived compounds, like modulation of cellular redox state, involvement in signal transduction and post-translational modification of proteins by sulfane sulfur or by formation of mixed disulfides (S-thiolation reactions).

  18. Friction properties of biological functional materials: PVDF membranes.

    PubMed

    Chen, Long; Di, Changan; Chen, Xuguang; Li, Zhengzhi; Luo, Jia

    2017-01-02

    Touch is produced by sensations that include approaching, sliding, pressing, and temperature. This concept has become a target of research in biotechnology, especially in the field of bionic biology. This study measured sliding and pressing with traditional tactile sensors in order to improve a machine operator's judgment of surface roughness. Based on the theory of acoustic emission, this study combined polyvinylidene fluoride (PVDF) with a sonic transducer to produce tactile sensors that can detect surface roughness. Friction between PVDF films and experimental materials generated tiny acoustic signals that were transferred into electrical signals through a sonic transducer. The characteristics of the acoustic signals for the various materials were then analyzed. The results suggest that this device can effectively distinguish among different objects based on roughness. Tactile sensors designed using this principle and structure function very similarly to the human body in recognizing the surface of an object.

  19. Terahertz vibrational properties of water nanoclusters relevant to biology.

    PubMed

    Johnson, Keith

    2012-01-01

    Water nanoclusters are shown from first-principles calculations to possess unique terahertz-frequency vibrational modes in the 1-6 THz range, corresponding to O-O-O "bending," "squashing," and "twisting" "surface" distortions of the clusters. The cluster molecular-orbital LUMOs are huge Rydberg-like "S," "P," "D," and "F" orbitals that accept an extra electron via optical excitation, ionization, or electron donation from interacting biomolecules. Dynamic Jahn-Teller coupling of these "hydrated-electron" orbitals to the THz vibrations promotes such water clusters as vibronically active "structured water" essential to biomolecular function such as protein folding. In biological microtubules, confined water-cluster THz vibrations may induce their "quantum coherence" communicated by Jahn-Teller phonons via coupling of the THz electromagnetic field to the water clusters' large electric dipole moments.

  20. Phytochrome from Green Plants: Properties and biological Function

    SciTech Connect

    Quail, Peter H.

    2014-07-25

    Plants constantly monitor the light environment for informational light signals used to direct adaptational responses to the prevailing conditions. One major such response, the Shade-Avaoidance Response (SAR), triggered when plants sense the presence of competing neighbors, results in enhanced channeling of photosynthetically-fixed carbon into stem elongation at the expense of deposition in reproductive tissues. This response has been selected against in many modern food crops to ensure maximum edible yield (e.g. seeds). Converse enhancement of the SAR, with consequent increased carbon channeling into vegetative cellulose, could contribute to the generation of crops with improved yield of tissues suitable for cellulosic biofuel production. The signal for this response is light enriched in far-red wavelengths. This signal is produced by sunlight filtered through, or reflected from, neighboring vegetation, as a result of preferential depletion of red photons through chlorophyll absorption. The plant phytochrome (phy) photoreceptor system (predominantly phyB) senses this signal through its capacity to switch reversibly, in milliseconds, between two molecular states: the biologically inactive Pr (red-light-absorbing) and biologically active Pfr (far-red-light-absorbing) conformers. The photoequilibrium established between these two conformers in light-grown plants is determined by the ratio of red-to-far-red wavelengths in the incoming signal. The levels of Pfr then dictate the recipient plant’s growth response: high levels suppress elongation growth; low levels promote elongation growth. Studies on seedling deetiolation have advanced our understanding considerably in recent years, of the mechanism by which the photoactivated phy molecule transduces its signal into cellular growth responses. The data show that a subfamily of phy-interacting bHLH transcription factors (PIFs) promote skotomorphogenic seedling development in post-germinative darkness, but that the phy

  1. Mechanical properties of the beetle elytron, a biological composite material.

    PubMed

    Lomakin, Joseph; Huber, Patricia A; Eichler, Christian; Arakane, Yasuyuki; Kramer, Karl J; Beeman, Richard W; Kanost, Michael R; Gehrke, Stevin H

    2011-02-14

    We determined the relationship between composition and mechanical properties of elytra (modified forewings that are composed primarily of highly sclerotized dorsal and less sclerotized ventral cuticles) from the beetles Tribolium castaneum (red flour beetle) and Tenebrio molitor (yellow mealworm). Elytra of both species have similar mechanical properties at comparable stages of maturation (tanning). Shortly after adult eclosion, the elytron of Tenebrio is ductile and soft with a Young's modulus (E) of 44 ± 8 MPa, but it becomes brittle and stiff with an E of 2400 ± 1100 MPa when fully tanned. With increasing tanning, dynamic elastic moduli (E') increase nearly 20-fold, whereas the frequency dependence of E' diminishes. These results support the hypothesis that cuticle tanning involves cross-linking of components, while drying to minimize plasticization has a lesser impact on cuticular stiffening and frequency dependence. Suppression of the tanning enzymes laccase-2 (TcLac2) or aspartate 1-decarboxylase (TcADC) in Tribolium altered mechanical characteristics consistent with hypotheses that (1) ADC suppression favors formation of melanic pigment with a decrease in protein cross-linking and (2) Lac2 suppression reduces both cuticular pigmentation and protein cross-linking.

  2. Fractal Scaling of Particle Size Distribution and Relationships with Topsoil Properties Affected by Biological Soil Crusts

    PubMed Central

    Gao, Guang-Lei; Ding, Guo-Dong; Wu, Bin; Zhang, Yu-Qing; Qin, Shu-Gao; Zhao, Yuan-Yuan; Bao, Yan-Feng; Liu, Yun-Dong; Wan, Li; Deng, Ji-Feng

    2014-01-01

    Background Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. Methodology/Principal Findings To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (P<0.05); and soil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R2 = 0.494∼0.955, P<0.01). Conclusions/Significance Biological soil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions. PMID:24516668

  3. Structures and physical properties of gaseous metal cationized biological ions.

    PubMed

    Burt, Michael B; Fridgen, Travis D

    2012-01-01

    Metal chelation can alter the activity of free biomolecules by modifying their structures or stabilizing higher energy tautomers. In recent years, mass spectrometric techniques have been used to investigate the effects of metal complexation with proteins, nucleobases and nucleotides, where small conformational changes can have significant physiological consequences. In particular, infrared multiple photon dissociation spectroscopy has emerged as an important tool for determining the structure and reactivity of gas-phase ions. Unlike other mass spectrometric approaches, this method is able to directly resolve structural isomers using characteristic vibrational signatures. Other activation and dissociation methods, such as blackbody infrared radiative dissociation or collision-induced dissociation can also reveal information about the thermochemistry and dissociative pathways of these biological ions. This information can then be used to provide information about the structures of the ionic complexes under study. In this article, we review the use of gas-phase techniques in characterizing metal-bound biomolecules. Particular attention will be given to our own contributions, which detail the ability of metal cations to disrupt nucleobase pairs, direct the self-assembly of nucleobase clusters and stabilize non-canonical isomers of amino acids.

  4. Biological residues define the ice nucleation properties of soil dust

    NASA Astrophysics Data System (ADS)

    Conen, F.; Morris, C. E.; Leifeld, J.; Yakutin, M. V.; Alewell, C.

    2011-06-01

    Soil dust is a major driver of ice nucleation in clouds leading to precipitation. It consists largely of mineral particles with a small fraction of organic matter constituted mainly of remains of micro-organisms that participated in degrading plant debris before their own decay. Some micro-organisms have been shown to be much better ice nuclei than the most efficient soil mineral. Yet, current aerosol schemes in global climate models do not consider a difference between soil dust and mineral dust in terms of ice nucleation activity. Here, we show that particles from the clay and silt size fraction of four different soils naturally associated with 0.7 to 11.8 % organic carbon (w/w) can have up to four orders of magnitude more ice nuclei per unit mass active in the immersion freezing mode at -12 °C than montmorillonite, the most efficient pure clay mineral. Most of this activity was lost after heat treatment. Removal of biological residues reduced ice nucleation activity to, or below that of montmorillonite. Desert soils, inherently low in organic content, are a large natural source of dust in the atmosphere. In contrast, agricultural land use is concentrated on fertile soils with much larger organic matter contents than found in deserts. It is currently estimated that the contribution of agricultural soils to the global dust burden is less than 20 %. Yet, these disturbed soils can contribute ice nuclei to the atmosphere of a very different and much more potent kind than mineral dusts.

  5. BIOLOGICAL AND BIOPHYSICAL PROPERTIES OF VASCULAR CONNEXIN CHANNELS

    PubMed Central

    Johnstone, Scott; Isakson, Brant; Locke, Darren

    2010-01-01

    Intercellular channels formed by connexin proteins play a pivotal role in the direct movement of ions and larger cytoplasmic solutes between vascular endothelial cells, between vascular smooth muscle cells, and between endothelial and smooth muscle cells. Multiple genetic and epigenetic factors modulate connexin expression levels and/or channel function, including cell type-independent and cell type-specific transcription factors, posttranslational modification and localized membrane targeting. Additionally, differences in protein-protein interactions, including those between connexins, significantly contribute to both vascular homeostasis and disease progression. The biophysical properties of the connexin channels identified in the vasculature, those formed by Cx37, Cx40, Cx43 and/or Cx45 proteins, are discussed in this review in the physiological and pathophysiological context of vessel function. PMID:19815177

  6. Evaluation of biological properties and clinical effectiveness of Aloe vera: A systematic review

    PubMed Central

    Radha, Maharjan H.; Laxmipriya, Nampoothiri P.

    2014-01-01

    Aloe vera (蘆薈 lú huì) is well known for its considerable medicinal properties. This plant is one of the richest natural sources of health for human beings coming. The chemistry of the plant has revealed the presence of more than 200 different biologically active substances. Many biological properties associated with Aloe species are contributed by inner gel of the leaves. Most research has been centralized on the biological activities of the various species of Aloe, which include antibacterial and antimicrobial activities of the nonvolatile constituents of the leaf gel. Aloe species are widely distributed in the African and the eastern European continents, and are spread almost throughout the world. The genus Aloe has more than 400 species but few, such as A. vera, Aloe ferox, and Aloe arborescens, are globally used for trade. A. vera has various medicinal properties such as antitumor, antiarthritic, antirheumatoid, anticancer, and antidiabetic properties. In addition, A. vera has also been promoted for constipation, gastrointestinal disorders, and for immune system deficiencies. However, not much convincing information is available on properties of the gel. The present review focuses on the detailed composition of Aloe gel, its various phytocomponents having various biological properties that help to improve health and prevent disease conditions. PMID:26151005

  7. Evaluation of biological properties and clinical effectiveness of Aloe vera: A systematic review.

    PubMed

    Radha, Maharjan H; Laxmipriya, Nampoothiri P

    2015-01-01

    Aloe vera ( lú huì) is well known for its considerable medicinal properties. This plant is one of the richest natural sources of health for human beings coming. The chemistry of the plant has revealed the presence of more than 200 different biologically active substances. Many biological properties associated with Aloe species are contributed by inner gel of the leaves. Most research has been centralized on the biological activities of the various species of Aloe, which include antibacterial and antimicrobial activities of the nonvolatile constituents of the leaf gel. Aloe species are widely distributed in the African and the eastern European continents, and are spread almost throughout the world. The genus Aloe has more than 400 species but few, such as A. vera, Aloe ferox, and Aloe arborescens, are globally used for trade. A. vera has various medicinal properties such as antitumor, antiarthritic, antirheumatoid, anticancer, and antidiabetic properties. In addition, A. vera has also been promoted for constipation, gastrointestinal disorders, and for immune system deficiencies. However, not much convincing information is available on properties of the gel. The present review focuses on the detailed composition of Aloe gel, its various phytocomponents having various biological properties that help to improve health and prevent disease conditions.

  8. Reverse pharmacognosy: identifying biological properties for plants by means of their molecule constituents: application to meranzin.

    PubMed

    Do, Quoc-Tuan; Lamy, Cécile; Renimel, Isabelle; Sauvan, Nancy; André, Patrice; Himbert, Franck; Morin-Allory, Luc; Bernard, Philippe

    2007-10-01

    Reverse pharmacognosy aims at finding biological targets for natural compounds by virtual or real screening and identifying natural resources that contain the active molecules. We report herein a study focused on the identification of biological properties of meranzin, a major component isolated from Limnocitrus littoralis (Miq.) Swingle. Selnergy, an IN SILICO biological profiling software, was used to identify putative binding targets of meranzin. Among the 400 screened proteins, 3 targets were selected: COX1, COX2 and PPARgamma. Binding tests were realised for these 3 protein candidates, as well as two negative controls. The predictions made by Selnergy were consistent with the experimental results, meaning that these 3 targets can be modulated by an extract containing this compound in a suitable concentration. These results demonstrate that reverse pharmacognosy and its inverse docking component is a powerful tool to identify biological properties for natural molecules and hence for plants containing these compounds.

  9. [SEROLOGICAL PROPERTIES AND BIOLOGICAL ACTIVITY OF PANTOEA AGGLOMERANS LIPOPOLYSACCHARIDES].

    PubMed

    Bulygina, T V; Yakovleva, L M; Brovarska, O S; Varbanets, L D

    2015-01-01

    The serological and phytotoxic properties of lipopolysaccharide (LPS) of plant pathogens--Pantoea agglomerans were studied. It is known that the thin variations in the structure of the O-specific polysaccharides determining serological specificity of gram- negative bacteria and used as a molecular basis of serological classification schemes. For P. agglomerans still does not exist a classification scheme based on serology specificity of their LPS. The results of cross serological tests demonstrate immunochemical heterogeneity of species P agglomerans. Only three strains of the 8488, 8490 and 7969 according to the agglutination of O-antigens and direct hemagglutination and inhibition direct hemagglutination can be attributed to a single serogroup. Other strains--each separate group, although some have a relationship. Compared with control plants under the influence of seed treatment of LPS in plants may be reduced, and in some cases increased root length, height and weight sprout, depending on the strain from which the selected LPS. Dive seedlings of tomatoes in the solutions of the studied preparations FSC caused the loss, and after some time, restore turgor.

  10. Physical and biological properties of yam as a saliva substitute.

    PubMed

    Park, Moon-Soo; Chang, Ji-Youn; Kim, Yoon-Young; Kang, Jeong-Hyun; Kho, Hong-Seop

    2010-02-01

    The purpose of this study was to investigate the viscosity and wettability of a water-soluble extract of yam and its effects on lysozyme and peroxidase activities. Human whole saliva, yam tuber, hen egg-white lysozyme, and bovine lactoperoxidase were used. Viscosity was measured with a cone-and-plate digital viscometer, while wettability was determined by measuring the contact angle. Lysozyme activity was determined by the turbidimetric method. Peroxidase activity was determined using the NbsSCN assay. Hydroxyapatite beads were used as a solid-phase. The viscosity of the yam solution was proportional to its concentration, with diluted yam solutions at 1:5 and 1:10 in simulated salivary buffer displaying similar viscosity values to unstimulated whole saliva and stimulated whole saliva, respectively. The contact angle of yam solution was not significantly different according to the tested materials or yam concentrations. Contact angles of yam solutions on acrylic resin were higher than those of human saliva. Yam affected lysozyme and peroxidase activities, and those effects were different on the hydroxyapatite surface versus in solution. Hydroxyapatite-adsorbed yam increased subsequent adsorption of lysozyme and peroxidase. We objectively confirmed the similarity of the viscoelastic properties of yam and human saliva, suggesting a role for yam in the development of effective saliva substitutes. Copyright 2009 Elsevier Ltd. All rights reserved.

  11. DNA mesophases induced by spermidine: structural properties and biological implications.

    PubMed Central

    Pelta, J; Durand, D; Doucet, J; Livolant, F

    1996-01-01

    Conditions of formation of DNA aggregates by the addition of spermidine were determined with 146 base pair DNA fragments as a function of spermidine and NaCl concentration. Two different phases of spermidine-DNA complexes are obtained: a cholesteric liquid crystalline phase with a large helical pitch, with interhelix distances ranging from 31.6 to 32.6 A, and a columnar hexagonal phase with a restricted fluidity in which DNA molecules are more closely packed (29.85 +/- 0.05 A). In both phases, the DNA molecule retains its B form. These phases are always observed in equilibrium with the dilute isotropic solution, and their phase diagram is defined for a DNA concentration of 1 mg/ml. DNA liquid crystalline phases induced by spermidine are compared with the DNA mesophases already described in concentrated solutions in the absence of spermidine. We propose that the liquid crystalline character of the spermidine DNA complexes is involved in the stimulation of the functional properties of the DNA reported in numerous experimental articles, and we discuss how the nature of the phase could regulate the degree of activity of the molecule. Images FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 8 FIGURE 10 PMID:8804588

  12. Physical and biological properties of cationic triesters of phosphatidylcholine

    PubMed Central

    MacDonald, RC; Ashley, GW; Shida, MM; Rakhmanova, VA; Tarahovsky, YS; Pantazatos, DP; Kennedy, MT; Pozharski, EV; Baker, KA; Jones, RD; Rosenzweig, HS; Choi, KL; Qiu, R; McIntosh, TJ

    1999-01-01

    The properties of a new class of phospholipids, alkyl phosphocholine triesters, are described. These compounds were prepared from phosphatidylcholines through substitution of the phosphate oxygen by reaction with alkyl trifluoromethylsulfonates. Their unusual behavior is ascribed to their net positive charge and absence of intermolecular hydrogen bonding. The O-ethyl, unsaturated derivatives hydrated to generate large, unilamellar liposomes. The phase transition temperature of the saturated derivatives is very similar to that of the precursor phosphatidylcholine and quite insensitive to ionic strength. The dissociation of single molecules from bilayers is unusually facile, as revealed by the surface activity of aqueous liposome dispersions. Vesicles of cationic phospholipids fused with vesicles of anionic lipids. Liquid crystalline cationic phospholipids such as 1, 2-dioleoyl-sn-glycero-3-ethylphosphocholine triflate formed normal lipid bilayers in aqueous phases that interacted with short, linear DNA and supercoiled plasmid DNA to form a sandwich-structured complex in which bilayers were separated by strands of DNA. DNA in a 1:1 (mol) complex with cationic lipid was shielded from the aqueous phase, but was released by neutralizing the cationic charge with anionic lipid. DNA-lipid complexes transfected DNA into cells very effectively. Transfection efficiency depended upon the form of the lipid dispersion used to generate DNA-lipid complexes; in the case of the O-ethyl derivative described here, large vesicle preparations in the liquid crystalline phase were most effective. PMID:10545361

  13. Bioactive glass/hydroxyapatite composites: mechanical properties and biological evaluation.

    PubMed

    Bellucci, Devis; Sola, Antonella; Anesi, Alexandre; Salvatori, Roberta; Chiarini, Luigi; Cannillo, Valeria

    2015-06-01

    Bioactive glass/hydroxyapatite composites for bone tissue repair and regeneration have been produced and discussed. The use of a recently developed glass, namely BG_Ca/Mix, with its low tendency to crystallize, allowed one to sinter the samples at a relatively low temperature thus avoiding several adverse effects usually reported in the literature, such as extensive crystallization of the glassy phase, hydroxyapatite (HA) decomposition and reaction between HA and glass. The mechanical properties of the composites with 80wt.% BG_Ca/Mix and 20wt.% HA are sensibly higher than those of Bioglass® 45S5 reference samples due to the presence of HA (mechanically stronger than the 45S5 glass) and to the thermal behaviour of the BG_Ca/Mix, which is able to favour the sintering process of the composites. Biocompatibility tests, performed with murine fibroblasts BALB/3T3 and osteocites MLO-Y4 throughout a multi-parametrical approach, allow one to look with optimism to the produced composites, since both the samples themselves and their extracts do not induce negative effects in cell viability and do not cause inhibition in cell growth.

  14. Complex fluids: probing mechanical properties of biological systems with optical tweezers.

    PubMed

    Ou-Yang, H Daniel; Wei, Ming-Tzo

    2010-01-01

    The mechanical properties of cells are crucial for cell sensing and reaction to mechanical environments. This review describes the basic principles of optical tweezers and their use as force sensors for studying the mechanical properties of biological systems. It covers experiments of four groups of biological systems arranged by increasing complexity: (a) packaging DNA into viral capsids by bacteriophage portal motors and the dynamical stiffness of DNA upon protein binding, (b) actin-coated giant vesicles and the myosin-II embedded actin polymer network, (c) suspension cells, and (d) adhesion cells. These examples demonstrate how optical tweezers have been used to improve the understanding of the mechanical properties of biological systems at subcellular and molecular levels.

  15. Physicochemical and biological properties of biomimetic mineralo-protein nanoparticles formed spontaneously in biological fluids.

    PubMed

    Peng, Hsin-Hsin; Wu, Cheng-Yeu; Young, David; Martel, Jan; Young, Andrew; Ojcius, David M; Lee, Yu-Hsiu; Young, John D

    2013-07-08

    Recent studies indicate that mineral nanoparticles (NPs) form spontaneously in human body fluids. These biological NPs represent mineral precursors that are associated with ectopic calcifications seen in various human diseases. However, the parameters that control the formation of mineral NPs and their possible effects on human cells remain poorly understood. Here a nanomaterial approach to study the formation of biomimetic calcium phosphate NPs comparable to their physiological counterparts is described. Particle sizing using dynamic light scattering reveals that serum and ion concentrations within the physiological range yield NPs below 100 nm in diameter. While the particles are phagocytosed by macrophages in a size-independent manner, only large particles or NP aggregates in the micrometer range induce cellular responses that include production of mitochondrial reactive oxygen species, caspase-1 activation, and secretion of interleukin-1β (IL-1β). A comprehensive proteomic analysis reveals that the particle-bound proteins are similar in terms of their identity and number, regardless of particle size, suggesting that protein adsorption is independent of particle size and curvature. In conclusion, the conditions underlying the formation of mineralo-protein particles are similar to the ones that form in vivo. While mineral NPs do not activate immune cells, they may become pro-inflammatory and contribute to pathological processes once they aggregate and form larger mineral particles. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Structure and mechanical properties of Saxidomus purpuratus biological shells.

    PubMed

    Yang, W; Zhang, G P; Zhu, X F; Li, X W; Meyers, M A

    2011-10-01

    The strength and fracture behavior of Saxidomus purpuratus shells were investigated and correlated with the structure. The shells show a crossed lamellar structure in the inner and middle layers and a fibrous/blocky and porous structure composed of nanoscaled particulates (~100 nm diameter) in the outer layer. It was found that the flexure strength and fracture mode are a function of lamellar organization and orientation. The crossed lamellar structure of this shell is composed of domains of parallel lamellae with approximate thickness of 200-600 nm. These domains have approximate lateral dimensions of 10-70 μm with a minimum of two orientations of lamellae in the inner and middle layers. Neighboring domains are oriented at specific angles and thus the structure forms a crossed lamellar pattern. The microhardness across the thickness was lower in the outer layer because of the porosity and the absence of lamellae. The tensile (from flexure tests) and compressive strengths were analyzed by means of Weibull statistics. The mean tensile (flexure) strength at probability of 50%, 80-105 MPa, is on the same order as the compressive strength (~50-150 MPa) and the Weibull moduli vary from 3.0 to 7.6. These values are significantly lower than abalone nacre, in spite of having the same aragonite structure. The lower strength can be attributed to a smaller fraction of the organic interlayer. The fracture path in the specimens is dominated by the orientation of the domains and proceeds preferentially along lamella boundaries. It also correlates with the color changes in the cross section of the shell. The cracks tend to undergo a considerable change in orientation when the color changes abruptly. The distributions of strengths, cracking paths, and fracture surfaces indicate that the mechanical properties of the shell are anisotropic with a hierarchical nature.

  17. Autofluorescence And Other Optical Properties As Tools In Biological Oceanography

    NASA Astrophysics Data System (ADS)

    Cullen, John J.; Yentsch, Clarice M.; Cucci, Terry L.; MacIntyre, Hugh L.

    1988-08-01

    Bulk fluorescence measurements have been popular in algal culture studies and in oceanographic and limnological applications. Usually, fluorescence is interpreted as an indicator of chlorophyll concentration or phytoplankton biomass, but sometimes measurements of fluorescence can be related to physiological properties of phytoplankton, such as responses to light. Now that in situ fluorometers are being deployed routinely with optical packages, there is active interest in interpreting the relationships between fluorescence, beam transmission, diffuse attenuation, and the physiological characteristics of phytoplankton. Flow cytometry offers the potential to extend these interpretations to the scale of individual cells. It may be difficult to compare measurements of fluorescence, however, because instruments differ greatly in excitation irradiance and time scale of measurement. With this in mind, we examined the short-term responses of a marine diatom to bright light, comparing different instruments (SeaTech in situ fluorometer, Turner Designs fluorometer, EPICS flow cytometer, FACS Analyzer, SeaTech beam transmissometer) while making concurrent measurements of photosynthesis vs irradiance and absorption spectra. Each fluorometer yielded somewhat different information, yet all showed a similar pattern of inhibition after exposure. One instrument, the in situ pulsed fluorometer, could show rapid changes of fluorescence immediately after large shifts of irradiance. Beam attenuation did not decline with the bright light treatment, nor did the specific absorption of chlorophyll. Photosynthetic efficiency was reduced after exposure to bright light, but the capacity for photosynthesis in high irradiance increased at the same time. These results are preliminary: nonetheless they support some interpretations of fluorescence/beam attenuation ratios, clarify some aspects of photosynthetic response to bright light, and suggest that flow cytometry may be useful for assessing

  18. Diacylglycerol Kinase-ε: Properties and Biological Roles

    PubMed Central

    Epand, Richard M.; So, Vincent; Jennings, William; Khadka, Bijendra; Gupta, Radhey S.; Lemaire, Mathieu

    2016-01-01

    In mammals there are at least 10 isoforms of diacylglycerol kinases (DGK). All catalyze the phosphorylation of diacylglycerol (DAG) to phosphatidic acid (PA). Among DGK isoforms, DGKε has several unique features. It is the only DGK isoform with specificity for a particular species of DAG, i.e., 1-stearoyl-2-arachidonoyl glycerol. The smallest of all known DGK isoforms, DGKε, is also the only DGK devoid of a regulatory domain. DGKε is the only DGK isoform that has a hydrophobic segment that is predicted to form a transmembrane helix. As the only membrane-bound, constitutively active DGK isoform with exquisite specificity for particular molecular species of DAG, the functional overlap between DGKε and other DGKs is predicted to be minimal. DGKε exhibits specificity for DAG containing the same acyl chains as those found in the lipid intermediates of the phosphatidylinositol-cycle. It has also been shown that DGKε affects the acyl chain composition of phosphatidylinositol in whole cells. It is thus likely that DGKε is responsible for catalyzing one step in the phosphatidylinositol-cycle. Steps of this cycle take place in both the plasma membrane and the endoplasmic reticulum membrane. DGKε is likely present in both of these membranes. DGKε is the only DGK isoform that is associated with a human disease. Indeed, recessive loss-of-function mutations in DGKε cause atypical hemolytic-uremic syndrome (aHUS). This condition is characterized by thrombosis in the small vessels of the kidney. It causes acute renal insufficiency in infancy and most patients develop end-stage renal failure before adulthood. Disease pathophysiology is poorly understood and there is no therapy. There are also data suggesting that DGKε may play a role in epilepsy and Huntington disease. Thus, DGKε has many unique molecular and biochemical properties when compared to all other DGK isoforms. DGKε homologs also contain a number of conserved sequence features that are distinctive

  19. Biological properties of a new volumizing hyaluronic acid filler: a systematic review.

    PubMed

    Ho, Derek; Jagdeo, Jared

    2015-01-01

    Hyaluronic acid (HA) dermal fillers are effective and safe for correction of facial rhytides. A new volumizing HA filler, 20 mg/ml HA dermal filler (Juvéderm® Voluma®, Allergan Inc., Irvine, CA), is the only HA filler with a FDA indication for facial volumization due to age-related facial volume loss. Evaluate the biological properties, including biochemical, biophysical and rheological, of this new 20 mg/ml HA dermal filler and discuss the importance of these properties in clinical applications. A systematic search of the computerized bibliographic databases Medline, Embase, Embal, Biosis, SciSearch, Pascal, HCAPlus, IPA, and Dissertation Abstracts with key term "Voluma." Four articles on the biological properties of this new 20 mg/ ml HA dermal filler were suitable for inclusion in this review. Biological analysis of elasticity and viscosity values of this new 20 mg/ml HA dermal filler demonstrated intermediate properties in three studies and high in one study compared to other HA dermal fillers. This 20 mg/ml HA dermal filler retained the highest elasticity and viscosity values at temperature of 37°C. Histology demonstrated that this 20 mg/ml HA dermal filler has an intermediate pattern of distribution within the superficial and deep reticular dermis. This 20 mg/ml HA dermal filler demonstrated volumizing ability, and maintaining viscosity and free-flowing characteristics for easy injection, tissue lifting, and molding. We hope future research incorporates biological properties analysis of this HA dermal filler in clinical trials.

  20. Simple empirical model for identifying rheological properties of soft biological tissues.

    PubMed

    Kobayashi, Yo; Tsukune, Mariko; Miyashita, Tomoyuki; Fujie, Masakatsu G

    2017-02-01

    Understanding the rheological properties of soft biological tissue is a key issue for mechanical systems used in the health care field. We propose a simple empirical model using fractional dynamics and exponential nonlinearity (FDEN) to identify the rheological properties of soft biological tissue. The model is derived from detailed material measurements using samples isolated from porcine liver. We conducted dynamic viscoelastic and creep tests on liver samples using a plate-plate rheometer. The experimental results indicated that biological tissue has specific properties: (i) power law increase in the storage elastic modulus and the loss elastic modulus of the same slope; (ii) power law compliance (gain) decrease and constant phase delay in the frequency domain; (iii) power law dependence between time and strain relationships in the time domain; and (iv) linear dependence in the low strain range and exponential law dependence in the high strain range between stress-strain relationships. Our simple FDEN model uses only three dependent parameters and represents the specific properties of soft biological tissue.

  1. Simple empirical model for identifying rheological properties of soft biological tissues

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yo; Tsukune, Mariko; Miyashita, Tomoyuki; Fujie, Masakatsu G.

    2017-02-01

    Understanding the rheological properties of soft biological tissue is a key issue for mechanical systems used in the health care field. We propose a simple empirical model using fractional dynamics and exponential nonlinearity (FDEN) to identify the rheological properties of soft biological tissue. The model is derived from detailed material measurements using samples isolated from porcine liver. We conducted dynamic viscoelastic and creep tests on liver samples using a plate-plate rheometer. The experimental results indicated that biological tissue has specific properties: (i) power law increase in the storage elastic modulus and the loss elastic modulus of the same slope; (ii) power law compliance (gain) decrease and constant phase delay in the frequency domain; (iii) power law dependence between time and strain relationships in the time domain; and (iv) linear dependence in the low strain range and exponential law dependence in the high strain range between stress-strain relationships. Our simple FDEN model uses only three dependent parameters and represents the specific properties of soft biological tissue.

  2. Rheological properties of a biological thermo-responsive hydrogel produced from soybean oil polymers

    USDA-ARS?s Scientific Manuscript database

    The rheological properties of a newly developed biological thermo-hydrogel made from vegetable oil were investigated. The material named HPSO-HG is a hydrolytic product of polymerized soybean oil (PSO). HPSO-HG is a thermo-responsive gel, and it exhibited viscoelastic behavior above 2% (wt.%) at roo...

  3. Rheological properties of a biological thermo-responsive hydrogel produced from soybean oil polymers

    USDA-ARS?s Scientific Manuscript database

    The rheological properties of a newly developed biological thermo-hydrogel made from vegetable oil were investigated. The material named HPSO-VI is a hydrolytic product of polymerized soybean oil (PSO). HPSO-VI exhibited viscoelastic behavior above 2% (wt. %) at room temperature and viscous fluid ...

  4. Rheological Properties of a Biological Thermo-Hydrogel Produced from Soybean Oil Polymers

    USDA-ARS?s Scientific Manuscript database

    The rheological properties of a newly developed biological thermo-hydrogel made from vegetable oil were investigated. The material named HPSO-HG is a hydrolytic product of polymerized soybean oil (PSO). HPSO-HG exhibited viscoelastic behavior above 2% (wt.%) at room temperature and viscous fluid b...

  5. Intellectual property rights in synthetic biology: an anti-thesis to open access to research?

    PubMed

    Saukshmya, Trichi; Chugh, Archana

    2010-12-01

    Synthetic Biology is a surging area of contemporary life science based research that is rapidly evolving by virtue of its multidisciplinary composition and applications. Biology never before has seen such a gold rush and demonstrated potential for knowledge based economy. The area of synthetic biology is in a nascent and tender stage, however issues pertaining to open access to research versus the monopolistic intellectual property regime (specifically patents) have already started raising concerns in the emerging bio-based economy. The present study critically analyses the comparative benefits as well as lacunas of open access to research and patenting issues. It is noteworthy that both approaches for synthetic biology development have to co-exist in order to optimally benefit the society at large.

  6. Optical properties of dissolved organic matter (DOM): Effects of biological and photolytic degradation

    USGS Publications Warehouse

    Hansen, Angela; Kraus, Tamara; Pellerin, Brian; Fleck, Jacob; Downing, Bryan D.; Bergamaschi, Brian

    2016-01-01

    Advances in spectroscopic techniques have led to an increase in the use of optical properties (absorbance and fluorescence) to assess dissolved organic matter (DOM) composition and infer sources and processing. However, little information is available to assess the impact of biological and photolytic processing on the optical properties of original DOM source materials. We measured changes in commonly used optical properties and indices in DOM leached from peat soil, plants, and algae following biological and photochemical degradation to determine whether they provide unique signatures that can be linked to original DOM source. Changes in individual optical parameters varied by source material and process, with biodegradation and photodegradation often causing values to shift in opposite directions. Although values for different source materials overlapped at the end of the 111-day lab experiment, multivariate statistical analyses showed that unique optical signatures could be linked to original DOM source material even after degradation, with 17 optical properties determined by discriminant analysis to be significant (p<0.05) in distinguishing between DOM source and environmental processing. These results demonstrate that inferring the source material from optical properties is possible when parameters are evaluated in combination even after extensive biological and photochemical alteration.

  7. Biological Responses to Diesel Exhaust Particles (DEPs) Depend on the Physicochemical Properties of the DEPs

    PubMed Central

    Park, Eun-Jung; Roh, Jinkyu; Kang, Min-Sung; Kim, Soo Nam; Kim, Younghun; Choi, Sangdun

    2011-01-01

    Diesel exhaust particles (DEPs) are the main components of ambient particulate materials, including polyaromatic hydrocarbons (PAHs), n-PAHs, heavy metals, and gaseous materials. Many epidemiological, clinical, and toxicological studies have shown that ambient particles, including DEPs, are associated with respiratory disorders, such as asthma, allergic rhinitis, and lung cancer. However, the relationship between the biological response to DEPs and their chemical composition remains unclear. In this study, we investigated the physicochemical properties of DEPs before toxicological studies, and then administered a single intratracheal instillation of DEPs to mice. The mice were then killed 1, 7, 14 and 28 days after DEP exposure to observe the biological responses induced by DEPs over time. Our findings suggest that DEPs engulfed into cells induced a Th2-type inflammatory response followed by DNA damage, whereas DEPs not engulfed into cells induced a Th1-type inflammatory response. Further, the physicochemical properties, including surface charge, particle size, and chemical composition, of DEPs play a crucial role in determining the biological responses to DEPs. Consequently, we suggest that the biological response to DEPs depend on cell-particle interaction and the physicochemical properties of the particles. PMID:22039547

  8. [Fluorescent proteins: physical-chemical properties and application in cell biology].

    PubMed

    Stepanenko, O V; Verkhusha, V V; Kuznetsova, I M; Turoverov, K K

    2007-01-01

    Green fluorescent protein (GFP) from jellyfish Aequorea victoria is the most extensively studied and widely used in cell biology protein. At present novel naturally occurring GFP-like proteins have been discovered and enhanced mutants of Aequorea GFP have been created. These mutants differ from wild-type GFP by stability, value of quantum yield, absorption and fluorescence spectra position and photochemical properties. GFP-like proteins are the fast growing family. This review is an attempt to characterize the main groups of GFP-like proteins, describe their structure and mechanisms of chromophore formation and summarize the main trends of their utilization as markers and biosensors in cell and molecular biology.

  9. Biological Properties of Single Chemical–DNA Adducts: A Twenty Year Perspective

    PubMed Central

    Delaney, James C.; Essigmann, John M.

    2010-01-01

    The genome and its nucleotide precursor pool are under sustained attack by radiation, reactive oxygen and nitrogen species, chemical carcinogens, hydrolytic reactions, and certain drugs. As a result, a large and heterogeneous population of damaged nucleotides forms in all cells. Some of the lesions are repaired, but for those that remain, there can be serious biological consequences. For example, lesions that form in DNA can lead to altered gene expression, mutation, and death. This perspective examines systems developed over the past 20 years to study the biological properties of single DNA lesions. PMID:18072751

  10. Analysis of optically anisotropic properties of biological tissues under stretching based on differential Mueller matrix formalism

    NASA Astrophysics Data System (ADS)

    Chen, Hao-Wei; Huang, Chih-Ling; Lo, Yu-Lung; Chang, You-Ren

    2017-03-01

    The optical properties of biological tissues under stretching are investigated using a full-field ellipsometry technique based on a differential Mueller matrix formalism. Traditional photoelastic-based formalism for extracting the linear birefringence (LB) properties of stretched anisotropic optical samples ignores the effects of the other optical properties of the sample. By contrast, in the formalism proposed in this study, the LB, linear dichroism (LD), circular birefringence (CB), circular dichroism (CD), and depolarization (Dep) properties are fully decoupled. Simulations are performed to evaluate the performance of the two formalisms in extracting the LB properties of optically anisotropic samples with different degrees of Dep, CB, LD, and CD. The practical feasibility of the proposed all-parameter decoupled formalism is then demonstrated using chicken breast muscle tissue. In general, the results show that both formalisms provide a reliable LB measurement performance for healthy chicken breast tissue under stretching. However, while the LB-only formalism has good robustness toward scattering, its measurement performance is seriously degraded for samples with high CB. Thus, of the two formalisms, the proposed all-parameter decoupled formalism provides a more effective approach for examining the anisotropic properties of biological tissues under stretching.

  11. Polyelectrolyte properties of filamentous biopolymers and their consequences in biological fluids.

    PubMed

    Janmey, Paul A; Slochower, David R; Wang, Yu-Hsiu; Wen, Qi; Cēbers, Andrejs

    2014-03-14

    Anionic polyelectrolyte filaments are common in biological cells. DNA, RNA, the cytoskeletal filaments F-actin, microtubules, and intermediate filaments, and polysaccharides such as hyaluronan that form the pericellular matrix all have large net negative charge densities distributed over their surfaces. Several filamentous viruses with diameters and stiffnesses similar to those of cytoskeletal polymers also have similar negative charge densities. Extracellular protein filaments such collagen, fibrin and elastin, in contrast, have notably smaller charge densities and do not behave as highly charged polyelectrolytes in solution. This review summarizes data that demonstrate generic counterion-mediated effects on four structurally unrelated biopolymers of similar charge density: F-actin, vimentin, Pf1 virus, and DNA, and explores the possible biological and pathophysiological consequences of the polyelectrolyte properties of biological filaments.

  12. Time-resolved photoacoustic measurement for evaluation of viscoelastic properties of biological tissues

    NASA Astrophysics Data System (ADS)

    Zhao, Yue; Chen, Conggui; Liu, Hongwei; Yang, Sihua; Xing, Da

    2016-11-01

    In this letter, we proposed a method for viscoelastic characterization of biological tissues based on time-resolved photoacoustic measurement. The theoretical and experimental study was performed on the influence of viscoelasticity effects on photoacoustic generation. Taking the time delay between the photoacoustic signal and the exciting laser, the viscoelasticity distribution of biological tissues can be mapped. To validate our method, gelatin phantoms with different densities were measured. We also applied this method in discrimination between fat and liver to confirm the usefulness of the viscoelastic evaluation. Furthermore, pilot experiments were performed on atherosclerosis artery from an apolipoprotein E-knockout mouse to show the viscoelastic characterization of atherosclerotic plaque. Our results demonstrate that this technique has the potential for visualizing the biomechanical properties and lesions of biological tissues.

  13. Predicting spiral wave patterns from cell properties in a model of biological self-organization

    NASA Astrophysics Data System (ADS)

    Geberth, Daniel; Hütt, Marc-Thorsten

    2008-09-01

    In many biological systems, biological variability (i.e., systematic differences between the system components) can be expected to outrank statistical fluctuations in the shaping of self-organized patterns. In principle, the distribution of single-element properties should thus allow predicting features of such patterns. For a mathematical model of a paradigmatic and well-studied pattern formation process, spiral waves of cAMP signaling in colonies of the slime mold Dictyostelium discoideum, we explore this possibility and observe a pronounced anticorrelation between spiral waves and cell properties (namely, the firing rate) and particularly a clustering of spiral wave tips in regions devoid of spontaneously firing (pacemaker) cells. Furthermore, we observe local inhomogeneities in the distribution of spiral chiralities, again induced by the pacemaker distribution. We show that these findings can be explained by a simple geometrical model of spiral wave generation.

  14. Quantification of nanoscale density fluctuations using electron microscopy: Light-localization properties of biological cells

    SciTech Connect

    Pradhan, Prabhakar; Damania, Dhwanil; Turzhitsky, Vladimir; Subramanian, Hariharan; Backman, Vadim; Joshi, Hrushikesh M.; Dravid, Vinayak P.; Roy, Hemant K.; Taflove, Allen

    2010-12-13

    We report a study of the nanoscale mass-density fluctuations of heterogeneous optical dielectric media, including nanomaterials and biological cells, by quantifying their nanoscale light-localization properties. Transmission electron microscope images of the media are used to construct corresponding effective disordered optical lattices. Light-localization properties are studied by the statistical analysis of the inverse participation ratio (IPR) of the localized eigenfunctions of these optical lattices at the nanoscale. We validated IPR analysis using nanomaterials as models of disordered systems fabricated from dielectric nanoparticles. As an example, we then applied such analysis to distinguish between cells with different degrees of aggressive malignancy.

  15. Biological and physiocochemical properties of purified anti-DNP guinea-pig non-precipitating antibodies

    PubMed Central

    Margni, R. A.; Hajos, Silvia

    1973-01-01

    Methods for isolation and purification of precipitating and non-precipitating guinea-pig antibodies are described. The physicochemical properties of γ1 and γ2 non-precipitating antibodies are similar to γ1 and γ2 precipitating ones. Biological properties are also similar excepting the reverse Arthus reaction, which is positive with the precipitating and negative with the non-precipitating antibodies. Bivalence of these antibodies was experimentally demonstrated. Precipitating antibodies K0 do not differ greatly from those obtained with the corresponding non-precipitating ones. The incapacity to precipitates with the antigen may be a consequence of a steric impediment. ImagesFIG. 1 PMID:4267511

  16. Tackling the biophysical properties of sphingolipids to decipher their biological roles.

    PubMed

    Carreira, Ana C; Ventura, Ana E; Varela, Ana R P; Silva, Liana C

    2015-06-01

    From the most simple sphingoid bases to their complex glycosylated derivatives, several sphingolipid species were shown to have a role in fundamental cellular events and/or disease. Increasing evidence places lipid-lipid interactions and membrane structural alterations as central mechanisms underlying the action of these lipids. Understanding how these molecules exert their biological roles by studying their impact in the physical properties and organization of membranes is currently one of the main challenges in sphingolipid research. Herein, we review the progress in the state-of-the-art on the biophysical properties of sphingolipid-containing membranes, focusing on sphingosine, ceramides, and glycosphingolipids.

  17. [Study of some physical and biological properties of an endodontic sealer composed of calcium hydroxide].

    PubMed

    Birman, E G; Sampaio, J M; Magalhães, J; Sato, E

    1990-01-01

    The authors present a study of the physical and biological properties of a new endodontic cement known as Sealapex. In its composition the presence of calcium hydroxide is introduced in order to induce calcification of the periapical tissue. Our results using glass round cover slips implanted on the subcutaneous tissue of mice indicated a persistent foreign body reaction (60 days). The physical properties studied compared to N-Rickert ciment indicated, a decreased leakage. Adhesivity tests didn't give us significant values. Laboratorial studies and clinical trials are necessary to a complete acceptance of this new ciment in endodontic treatment.

  18. Review of temperature dependence of thermal properties, dielectric properties, and perfusion of biological tissues at hyperthermic and ablation temperatures

    PubMed Central

    Rossmann, Christian; Haemmerich, Dieter

    2016-01-01

    The application of supraphysiological temperatures (>40°C) to biological tissues causes changes at the molecular, cellular, and structural level, with corresponding changes in tissue function and in thermal, mechanical and dielectric tissue properties. This is particularly relevant for image-guided thermal treatments (e.g. hyperthermia and thermal ablation) delivering heat via focused ultrasound (FUS), radiofrequency (RF), microwave (MW), or laser energy; temperature induced changes in tissue properties are of relevance in relation to predicting tissue temperature profile, monitoring during treatment, and evaluation of treatment results. This paper presents a literature survey of temperature dependence of electrical (electrical conductivity, resistivity, permittivity) and thermal tissue properties (thermal conductivity, specific heat, diffusivity). Data of soft tissues (liver, prostate, muscle, kidney, uterus, collagen, myocardium and spleen) for temperatures between 5 to 90°C, and dielectric properties in the frequency range between 460 kHz and 3 GHz are reported. Furthermore, perfusion changes in tumors including carcinomas, sarcomas, rhabdomyosarcoma, adenocarcinoma and ependymoblastoma in response to hyperthmic temperatures up to 46°C are presented. Where appropriate, mathematical models to describe temperature dependence of properties are presented. The presented data is valuable for mathematical models that predict tissue temperature during thermal therapies (e.g. hyperthermia or thermal ablation), as well as for applications related to prediction and monitoring of temperature induced tissue changes. PMID:25955712

  19. Review of temperature dependence of thermal properties, dielectric properties, and perfusion of biological tissues at hyperthermic and ablation temperatures.

    PubMed

    Rossmanna, Christian; Haemmerich, Dieter

    2014-01-01

    The application of supraphysiological temperatures (>40°C) to biological tissues causes changes at the molecular, cellular, and structural level, with corresponding changes in tissue function and in thermal, mechanical and dielectric tissue properties. This is particularly relevant for image-guided thermal treatments (e.g. hyperthermia and thermal ablation) delivering heat via focused ultrasound (FUS), radiofrequency (RF), microwave (MW), or laser energy; temperature induced changes in tissue properties are of relevance in relation to predicting tissue temperature profile, monitoring during treatment, and evaluation of treatment results. This paper presents a literature survey of temperature dependence of electrical (electrical conductivity, resistivity, permittivity) and thermal tissue properties (thermal conductivity, specific heat, diffusivity). Data of soft tissues (liver, prostate, muscle, kidney, uterus, collagen, myocardium and spleen) for temperatures between 5 to 90°C, and dielectric properties in the frequency range between 460 kHz and 3 GHz are reported. Furthermore, perfusion changes in tumors including carcinomas, sarcomas, rhabdomyosarcoma, adenocarcinoma and ependymoblastoma in response to hyperthmic temperatures up to 46°C are presented. Where appropriate, mathematical models to describe temperature dependence of properties are presented. The presented data is valuable for mathematical models that predict tissue temperature during thermal therapies (e.g. hyperthermia or thermal ablation), as well as for applications related to prediction and monitoring of temperature induced tissue changes.

  20. Properties of alternative microbial hosts used in synthetic biology: towards the design of a modular chassis

    PubMed Central

    Kim, Juhyun; Salvador, Manuel; Saunders, Elizabeth; González, Jaime; Avignone-Rossa, Claudio

    2016-01-01

    The chassis is the cellular host used as a recipient of engineered biological systems in synthetic biology. They are required to propagate the genetic information and to express the genes encoded in it. Despite being an essential element for the appropriate function of genetic circuits, the chassis is rarely considered in their design phase. Consequently, the circuits are transferred to model organisms commonly used in the laboratory, such as Escherichia coli, that may be suboptimal for a required function. In this review, we discuss some of the properties desirable in a versatile chassis and summarize some examples of alternative hosts for synthetic biology amenable for engineering. These properties include a suitable life style, a robust cell wall, good knowledge of its regulatory network as well as of the interplay of the host components with the exogenous circuits, and the possibility of developing whole-cell models and tuneable metabolic fluxes that could allow a better distribution of cellular resources (metabolites, ATP, nucleotides, amino acids, transcriptional and translational machinery). We highlight Pseudomonas putida, widely used in many different biotechnological applications as a prominent organism for synthetic biology due to its metabolic diversity, robustness and ease of manipulation. PMID:27903818

  1. Analyzing resilience properties in oscillatory biological systems using parametric model checking.

    PubMed

    Andreychenko, Alexander; Magnin, Morgan; Inoue, Katsumi

    2016-11-01

    Automated verification of living organism models allows us to gain previously unknown knowledge about underlying biological processes. In this paper we show how parametric time model checking can be applied to define the time behavior of biological oscillatory systems more precisely. In particular, we focus on the resilience properties of such systems. This notion was introduced to understand the behavior of biological systems (e.g. the mammalian circadian rhythm) that are reactive and adaptive enough to endorse major changes in their environment (e.g. jet-lags, day-night alternating work-time). We formalize these properties through parametric TCTL and investigate the influence of environmental conditions changes on the resilience of living organisms under the uncertainty in parameters. In particular, we discuss the influence of various perturbations, e.g. artificial jet-lag or components knock-out on the parameters controlling the oscillatory behavior. This analysis is crucial when it comes to model elicitation for dynamic biological systems. We demonstrate the applicability of this technique using a simplified model of circadian clock and discuss its results with regard to other previous studies based on hybrid modeling. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Chemical and biological properties of quinochalcone C-glycosides from the florets of Carthamus tinctorius.

    PubMed

    Yue, Shijun; Tang, Yuping; Li, Shujiao; Duan, Jin-Ao

    2013-12-10

    Quinochalcone C-glycosides are regarded as characteristic components that have only been isolated from the florets of Carthamus tinctorius. Recently, quinochalcone C-glycosides were found to have multiple pharmacological activities, which has attracted the attention of many researchers to explore these compounds. This review aims to summarize quinochalcone C-glycosides' physicochemical properties, chromatographic behavior, spectroscopic characteristics, as well as their biological activities, which will be helpful for further study and development of quinochalcone C-glycosides.

  3. Structure-property relationship of quinuclidinium surfactants--Towards multifunctional biologically active molecules.

    PubMed

    Skočibušić, Mirjana; Odžak, Renata; Štefanić, Zoran; Križić, Ivana; Krišto, Lucija; Jović, Ozren; Hrenar, Tomica; Primožič, Ines; Jurašin, Darija

    2016-04-01

    Motivated by diverse biological and pharmacological activity of quinuclidine and oxime compounds we have synthesized and characterized novel class of surfactants, 3-hydroxyimino quinuclidinium bromides with different alkyl chains lengths (CnQNOH; n=12, 14 and 16). The incorporation of non conventional hydroxyimino quinuclidinium headgroup and variation in alkyl chain length affects hydrophilic-hydrophobic balance of surfactant molecule and thereby physicochemical properties important for its application. Therefore, newly synthesized surfactants were characterized by the combination of different experimental techniques: X-ray analysis, potentiometry, electrical conductivity, surface tension and dynamic light scattering measurements, as well as antimicrobial susceptibility tests. Comprehensive investigation of CnQNOH surfactants enabled insight into structure-property relationship i.e., way in which the arrangement of surfactant molecules in the crystal phase correlates with their solution behavior and biologically activity. The synthesized CnQNOH surfactants exhibited high adsorption efficiency and relatively low critical micelle concentrations. In addition, all investigated compounds showed very potent and promising activity against Gram-positive and clinically relevant Gram-negative bacterial strains compared to conventional antimicrobial agents: tetracycline and gentamicin. The overall results indicate that bicyclic headgroup with oxime moiety, which affects both hydrophilicity and hydrophobicity of CnQNOH molecule in addition to enabling hydrogen bonding, has dominant effect on crystal packing and physicochemical properties. The unique structural features of cationic surfactants with hydroxyimino quinuclidine headgroup along with diverse biological activity have made them promising structures in novel drug discovery. Obtained fundamental understanding how combination of different functionalities in a single surfactant molecule affects its physicochemical

  4. Differentiation of celosia mosaic virus and asparagus virus 1 based on biological properties.

    PubMed

    Owolabi, A T; Proll, E

    2000-01-01

    An attempt was made to distinguish between celosia mosaic virus (CIMV) and asparagus virus 1 (AV-1) based on biological properties, which hitherto was obscured from serological data from previous work. The host range of AV-1 was found to be a subset of that of CIMV and AV-1 was transmitted by the aphid Myzus persicae which, on the other hand, did not transmit CIMV. No evidence of cross-protection was obtained between these two viruses.

  5. Biological and genetic properties of the p53 null preneoplastic mammary epithelium

    NASA Technical Reports Server (NTRS)

    Medina, Daniel; Kittrell, Frances S.; Shepard, Anne; Stephens, L. Clifton; Jiang, Cheng; Lu, Junxuan; Allred, D. Craig; McCarthy, Maureen; Ullrich, Robert L.

    2002-01-01

    The absence of the tumor suppressor gene p53 confers an increased tumorigenic risk for mammary epithelial cells. In this report, we describe the biological and genetic properties of the p53 null preneoplastic mouse mammary epithelium in a p53 wild-type environment. Mammary epithelium from p53 null mice was transplanted serially into the cleared mammary fat pads of p53 wild-type BALB/c female to develop stable outgrowth lines. The outgrowth lines were transplanted for 10 generations. The outgrowths were ductal in morphology and progressed through ductal hyperplasia and ductal carcinoma in situ before invasive cancer. The preneoplastic outgrowth lines were immortal and exhibited activated telomerase activity. They are estrogen and progesterone receptor-positive, and aneuploid, and had various levels of tumorigenic potential. The biological and genetic properties of these lines are distinct from those found in most hyperplastic alveolar outgrowth lines, the form of mammary preneoplasia occurring in most traditional models of murine mammary tumorigenesis. These results indicate that the preneoplastic cell populations found in this genetically engineered model are similar in biological properties to a subset of precurser lesions found in human breast cancer and provide a unique model to identify secondary events critical for tumorigenicity and invasiveness.

  6. Biological and genetic properties of the p53 null preneoplastic mammary epithelium

    NASA Technical Reports Server (NTRS)

    Medina, Daniel; Kittrell, Frances S.; Shepard, Anne; Stephens, L. Clifton; Jiang, Cheng; Lu, Junxuan; Allred, D. Craig; McCarthy, Maureen; Ullrich, Robert L.

    2002-01-01

    The absence of the tumor suppressor gene p53 confers an increased tumorigenic risk for mammary epithelial cells. In this report, we describe the biological and genetic properties of the p53 null preneoplastic mouse mammary epithelium in a p53 wild-type environment. Mammary epithelium from p53 null mice was transplanted serially into the cleared mammary fat pads of p53 wild-type BALB/c female to develop stable outgrowth lines. The outgrowth lines were transplanted for 10 generations. The outgrowths were ductal in morphology and progressed through ductal hyperplasia and ductal carcinoma in situ before invasive cancer. The preneoplastic outgrowth lines were immortal and exhibited activated telomerase activity. They are estrogen and progesterone receptor-positive, and aneuploid, and had various levels of tumorigenic potential. The biological and genetic properties of these lines are distinct from those found in most hyperplastic alveolar outgrowth lines, the form of mammary preneoplasia occurring in most traditional models of murine mammary tumorigenesis. These results indicate that the preneoplastic cell populations found in this genetically engineered model are similar in biological properties to a subset of precurser lesions found in human breast cancer and provide a unique model to identify secondary events critical for tumorigenicity and invasiveness.

  7. Chemical and biological properties of supramolecular polymer systems based on oligocaprolactones.

    PubMed

    Dankers, Patricia Y W; van Leeuwen, Ellen N M; van Gemert, Gaby M L; Spiering, A J H; Harmsen, Martin C; Brouwer, Linda A; Janssen, Henk M; Bosman, Anton W; van Luyn, Marja J A; Meijer, E W

    2006-11-01

    We show that materials with a diverse range of mechanical and biological properties can be obtained using a modular approach by simply mixing different ratios of oligocaprolactones that are either end-functionalized or chain-extended with quadruple hydrogen bonding ureido-pyrimidinone (UPy) moieties. The use of two UPy-synthons allows for easy synthesis of UPy-modified polymers resulting in high yields. Comparison of end-functionalized UPy-polymers with chain-extended UPy-polymers shows that these polymers behave distinctively different regarding their material and biological properties. The end-modified UPy-polymer is rather stiff and brittle due to its high crystallinity. Disks made of this material fractures after subcutaneous implantation. The material shows a low inflammatory response which is accompanied by the formation of a fibrous capsule, reflecting the inertness of the material. The chain-extended UPy-material on the contrary is practically free of crystalline domains and shows clear flexible properties. This material deforms after in-vivo implantation, accompanied with cellular infiltration. By mixing both polymers, materials with intermediate properties concerning their mechanical and biological behaviour can be obtained. Surprisingly, a 20:80 mixture of both polymers with the chain-extended UPy-polymer in excess shows flexible properties without visible deformation upon implantation for 42 days. This mixture, a blend formed by intimate mixing through UPy-UPy interaction, also shows a mild tissue response accompanied with the formation of a thin capsule. The material does not become more crystalline upon implantation. Hence, this mixture might be an ideal scaffold material for soft tissue engineering due to its flexibility and diminished fibrous tissue formation, and illustrates the strength of the modular approach.

  8. Study optical properties of biological tissue in the presence of microbubbles

    NASA Astrophysics Data System (ADS)

    Assadi, Homa; Lee, Vincent; Karshafian, Raffi; Douplik, Alexandre

    2015-03-01

    Optical contrast agents introduce distinct features to induce detectable changes in native tissue properties [1]. In ultrasound imaging, microbubbles (MBs) - a gas-core shell-encapsulated agent - are used clinically as contrast agents. The working hypothesis of this study is that microbubbles can be employed as an intravascular contrast agent in optical imaging systems. Microbubbles can produce a refractive index mismatch which makes it distinguishable from surrounding media. In this work, the interaction of collimated light and microbubbles in a [1] biological phantom solution was investigated. The biological medium was comprised of intralipid and human blood which was constructed to cover the range of soft tissue optical properties. The effect of microbubbles on the optical properties such as reduced scattering and absorption coefficients were considered. Diffuse reflectance (DR) and total transmittance (TT) of a biological phantom solution were measured using a spectroscopic integrating sphere system in the absence and presence of Definity® microbubbles. The optical properties were computed using the inverse adding doubling (IAD) software. The presence of microbubbles increased DR and decreased TT of the phantom. In the presence of MB's (2.5% volume concentration), the reflectance of the phantom increased by 25% in the optical window. There is no absorption event and only scattering happened after light-microbubbles interactions. The reduced scattering coefficient increased significantly (30%) indicating the potential use of MBs as optical contrast agents. In conclusion, reflectance of a media can be enhanced by adding microbubbles to increase scattering properties and more light was detected returning to the surface of tissue.

  9. Biological properties of a thermally crosslinked gelatin film as a novel anti-adhesive material: Relationship between the biological properties and the extent of thermal crosslinking.

    PubMed

    Tsujimoto, Hiroyuki; Tanzawa, Ayumi; Miyamoto, Hiroe; Horii, Tsunehito; Tsuji, Misaki; Kawasumi, Akari; Tamura, Atsushi; Wang, Zhen; Abe, Rie; Tanaka, Shota; Yamanaka, Kouki; Matoba, Mari; Torii, Hiroko; Ozamoto, Yuki; Takamori, Hideki; Suzuki, Shuko; Morita, Shinichiro; Ikada, Yoshito; Hagiwara, Akeo

    2015-10-01

    In order to prevent postoperative adhesion and the related complications, a thermally crosslinked gelatin (TCG) film was developed and the basic biological properties were examined, paying special attention to the relationship between these properties and the extent of crosslinking of the film. The gelatin films crosslinked thermally for five different time periods (0, 1, 3, 8, and 14 hours) were developed and the following tests were performed. Regarding the material characterization of the films, the water content, the water solubility, and the enzymatic degradation for collagenase were found to be closely related to the duration of thermal crosslinking. In an in vitro study conducted to examine the cell growth of fibroblasts cultured on the films, the degree of cell growth, except no crosslinked film, was less than that observed in the control group, thus suggesting that such effects of the films on fibroblast cell growth may be related with their anti-adhesive effects. In in vivo tests, the films crosslinked for longer time periods (3, 8, and 14 hours) were retained for longer after being implanted into the abdominal cavity in rats and showed a significant anti-adhesive effect in the rat cecum adhesion models, indicating that the biodegradability and anti-adhesive effects of the TCG films depend on the duration of thermal crosslinking. In order to develop useful and effective anti-adhesive gelatin film, it is very important to optimize duration of the thermal crosslinking.

  10. Chitosan fibers with improved biological and mechanical properties for tissue engineering applications.

    PubMed

    Albanna, Mohammad Z; Bou-Akl, Therese H; Blowytsky, Oksana; Walters, Henry L; Matthew, Howard W T

    2013-04-01

    The low mechanical properties of hydrogel materials such as chitosan hinder their broad utility for tissue engineering applications. Previous research efforts improved the mechanical properties of chitosan fiber through chemical and physical modifications; however, unfavorable toxicity effects on cells were reported. In this paper, we report the preparation of chitosan fibers with improved mechanical and biocompatibility properties. The structure-property relationships of extruded chitosan fibers were explored by varying acetic acid (AA) concentration, ammonia concentration, annealing temperature and degree of heparin crosslinking. Results showed that optimizing AA concentration to 2vol% improved fiber strength and stiffness by 2-fold. Extruding chitosan solution into 25wt% of ammonia solution reduced fiber diameters and improved fiber strength by 2-fold and stiffness by 3-fold, due to an increase in crystallinity as confirmed by XRD. Fiber annealing further reduced fiber diameter and improved fiber strength and stiffness as temperature increased. Chitosan fibers crosslinked with heparin had increased diameter but lower strength and stiffness properties and higher breaking strain values. When individual parameters were combined, further improvement in fiber mechanical properties was achieved. All mechanically improved fibers and heparin crosslinked fibers promoted valvular interstitial cells (VIC) attachment and growth over 10 day cultures. Our results demonstrate the ability to substantially improve the mechanical properties of chitosan fibers without adversely affecting their biological properties. The investigated treatments offer numerous advantages over previous physical/chemical modifications and thus are expected to expand the utility of chitosan fibers with tunable mechanical properties in various tissue engineering applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Chemical variation in Piper aduncum and biological properties of its dillapiole-rich essential oil.

    PubMed

    de Almeida, Roseli R P; Souto, Raimundo N P; Bastos, Cleber N; da Silva, Milton H L; Maia, José G S

    2009-09-01

    The essential oils of the specimens of Piper aduncum that occur in deforested areas of Brazilian Amazon, North Brazil, are rich in dillapiole (35-90%), a derivative of phenylpropene, to which are attributed biological properties. On the other hand, the oils of the specimens with occurrence in the Atlantic Forest, and Northeastern and Southeastern Brazil, do not contain dillapiole, but only terpene compounds such as (E)-nerolidol and linalool. One specimen existing in the Amazon was hydrodistilled. The obtained oil was fractioned on a silica chromatographic column, resulting in fractions rich in dillapiole (95.0-98.9%) utilized for analyses by GC and GC/MS, structural characterization by NMR, confirmation of their biological properties, and to obtain the isomer isodillapiole. Dillapiole showed a fungicide action against the fungus Clinipellis perniciosa (witches' broom) by inhibition of its basidiospores, in concentrations ranging from 0.6 to 1.0 ppm. The larvicide and insecticide actions of dillapiole were tested against the larvae and the adult insects of Anopheles marajoara and Aedes aegypti (malaria and dengue mosquitoes), resulting in mortality of the larvae (48 h, 100%) at a concentration of 100 ppm, and mortality of the insects (30 min, 100%) at a concentration of 600 ppm. The isomeric isodillapiole showed no significant activity in the same biological tests.

  12. The sulfur-fumigation reduces chemical composition and biological properties of Angelicae Sinensis Radix.

    PubMed

    Zhan, Janis Ya-Xian; Yao, Ping; Bi, Cathy Wen-Chuan; Zheng, Ken Yu-Zhong; Zhang, Wendy Li; Chen, Jian-Ping; Dong, Tina Ting-Xia; Su, Zi-Ren; Tsim, Karl Wah-Keung

    2014-09-25

    Angelica Sinensis Radix (roots of Angelica sinensis; ASR) is a popular herbal supplement in China for promoting blood circulation. Today, sulfur-fumigation is commonly used to treat ASR as a means of pest control; however, the studies of sulfur-fumigation on the safety and efficacy of ASR are very limited. Here, we elucidated the destructive roles of sulfur-fumigation on ASR by chemical and biological assessments. After sulfur-fumigation, the chemicals in ASR were significantly lost. The biological activities of anti-platelet aggregation, induction of NO production and estrogenic properties were compared between the water extracts of non-fumigated and sulfur-fumigated ASR. In all cases, the sulfur-fumigation significantly reduced the biological properties of ASR. In addition, application of water extract deriving from sulfur-fumigated ASR showed toxicity to cultured MCF-7 cells. In order to ensure the safety and to achieve the best therapeutic effect, it is recommended that sulfur-fumigation is an unacceptable approach for processing herbal materials. Copyright © 2014 Elsevier GmbH. All rights reserved.

  13. Fabrication and in vitro biological properties of piezoelectric bioceramics for bone regeneration.

    PubMed

    Tang, Yufei; Wu, Cong; Wu, Zixiang; Hu, Long; Zhang, Wei; Zhao, Kang

    2017-02-27

    The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO3) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d33 of HA/BaTiO3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO3 piezoelectric ceramics.

  14. Fabrication and in vitro biological properties of piezoelectric bioceramics for bone regeneration

    PubMed Central

    Tang, Yufei; Wu, Cong; Wu, Zixiang; Hu, Long; Zhang, Wei; Zhao, Kang

    2017-01-01

    The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO3) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d33 of HA/BaTiO3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO3 piezoelectric ceramics. PMID:28240268

  15. Fabrication and in vitro biological properties of piezoelectric bioceramics for bone regeneration

    NASA Astrophysics Data System (ADS)

    Tang, Yufei; Wu, Cong; Wu, Zixiang; Hu, Long; Zhang, Wei; Zhao, Kang

    2017-02-01

    The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO3) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d33 of HA/BaTiO3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO3 piezoelectric ceramics.

  16. Group-10 metal complexes of biological molecules and related ligands: structural and functional properties.

    PubMed

    Shimazaki, Yuichi; Yamauchi, Osamu

    2012-09-01

    The complexes of group-10 metals, Ni, Pd, and Pt, with biological molecules and related ligands have been attracting increasing attention in recent years due to their reactivities and functions, such as catalysts and drugs, and their biological relevance. The well-defined structures and kinetic inertness especially of Pt complexes have been used as the sites for weak interactions with other molecules. The Ni complexes have been reported as models not only for Ni enzymes but also for other metalloenzyme active sites for deeper understanding of the reactivities such as oxygen activations and detailed electronic structures. Pd Complexes are widely known for their catalytic activities in conversions of various organic molecules including useful biological molecules, such as Suzuki-Miyaura cross-coupling, while Pt complexes have been intensively studied for their antitumor activities. We focus in this review on our recent results on weak interactions and reactivities of the group-10 metal complexes with biological molecules and related compounds, and discuss their structural features and some new properties pointing to functional possibilities. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.

  17. Physicochemical Properties, Biological Activity, Health Benefits, and General Limitations of Aged Black Garlic: A Review.

    PubMed

    Ryu, Ji Hyeon; Kang, Dawon

    2017-06-01

    Garlic (Allium sativum) has been used as a medicinal food since ancient times. However, some people are reluctant to ingest raw garlic due to its unpleasant odor and taste. Therefore, many types of garlic preparations have been developed to reduce these attributes without losing biological functions. Aged black garlic (ABG) is a garlic preparation with a sweet and sour taste and no strong odor. It has recently been introduced to Asian markets as a functional food. Extensive in vitro and in vivo studies have demonstrated that ABG has a variety of biological functions such as antioxidant, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, anti-allergic, cardioprotective, and hepatoprotective effects. Recent studies have compared the biological activity and function of ABG to those of raw garlic. ABG shows lower anti-inflammatory, anti-coagulation, immunomodulatory, and anti-allergic effects compared to raw garlic. This paper reviews the physicochemical properties, biological activity, health benefits, adverse effects, and general limitations of ABG.

  18. Some reactions and properties of nitro radical-anions important in biology and medicine.

    PubMed Central

    Wardman, P

    1985-01-01

    Nitroaromatic compounds, ArNO2 have widespread actual or potential use in medicine and cancer therapy. There is direct proof that free-radical metabolites are involved in many applications, and an appreciation of the conceptual basis for their therapeutic differential; however, an understanding of the detailed mechanisms involved is lacking. Redox properties control most biological responses of nitro compounds, and the characteristics of the one-electron couple: ArNO2/ArNO2- are detailed. The "futile metabolism" of nitroaryl compounds characteristic of most aerobic nitroreductase systems reflects competition between natural radical-decay pathways and a one-electron transfer reaction to yield superoxide ion, O2-. Prototropic properties control the rate of radical decay, and redox properties control the rate of electron transfer to O2 or other acceptors. There are clear parallels in the chemistry of ArNO2- and O2-. While nitro radicals have frequently been invoked as damaging species, they are very unreactive (except as simple reductants). It seems likely that reductive metabolism of nitroaryl compounds, although generally involving nitro radical-anions as obligate intermediates (and this is required for therapeutic selectivity towards anaerobes), results in biological damage via reductive metabolites of higher reduction order than the one-electron product. PMID:3830700

  19. Three-Dimensional Aggregates of Mesenchymal Stem Cells: Cellular Mechanisms, Biological Properties, and Applications

    PubMed Central

    Sart, Sébastien; Tsai, Ang-Chen; Li, Yan

    2014-01-01

    Mesenchymal stem cells (MSCs) are primary candidates in cell therapy and tissue engineering and are being tested in clinical trials for a wide range of diseases. Originally isolated and expanded as plastic adherent cells, MSCs have intriguing properties of in vitro self-assembly into three-dimensional (3D) aggregates reminiscent of skeletal condensation in vivo. Recent studies have shown that MSC 3D aggregation improved a range of biological properties, including multilineage potential, secretion of therapeutic factors, and resistance against ischemic condition. Hence, the formation of 3D MSC aggregates has been explored as a novel strategy to improve cell delivery, functional activation, and in vivo retention to enhance therapeutic outcomes. This article summarizes recent reports of MSC aggregate self-assembly, characterization of biological properties, and their applications in preclinical models. The cellular and molecular mechanisms underlying MSC aggregate formation and functional activation are discussed, and the areas that warrant further investigation are highlighted. These analyses are combined to provide perspectives for identifying the controlling mechanisms and refining the methods of aggregate fabrication and expansion for clinical applications. PMID:24168395

  20. Microwave processed nanocrystalline hydroxyapatite: Simultaneous enhancement of mechanical and biological properties

    PubMed Central

    Bose, Susmita; Dasgupta, Sudip; Tarafder, Solaiman; Bandyopadhyay, Amit

    2010-01-01

    Despite excellent bioactivity of hydroxyapatite (HA) ceramics, poor mechanical strength has limited its applications primarily to coatings and other non-load bearing areas as bone grafts. Using synthesized HA nanopowder, dense compacts with grain sizes in nanometers to micrometers were processed via microwave sintering between 1000 and 1150 °C for 20 minutes. Here we demonstrate that mechanical properties, such as compressive strength, hardness and indentation fracture toughness of HA compacts increased with a decrease in grain size. HA with 168± 86 nm grain size showed the highest compressive strength of 395±42 MPa, hardness of 8.4±0.4 GPa and indentation fracture toughness of 1.9 ±0.2 MPam1/2. To study the in vitro biological properties, HA compacts with grain size between 168 nm and 1.16 µm were assessed for in vitro bone cell-materials interactions with human osteoblast cell line. Vinculin protein expression for cell attachment and bone cell proliferation using MTT assay showed surfaces with finer grains provided better bone cell-materials interactions than coarse grained samples. Our results indicate simultaneous improvements in mechanical and biological properties in microwave sintered HA compacts with nanoscale grain size. PMID:20230922

  1. Emerging differentiation of folkbiology and folkpsychology: attributions of biological and psychological properties to living things.

    PubMed

    Coley, J D

    1995-12-01

    Research suggests that for adults, "folkpsychology" and "folkbiology" represent distinct conceptual domains for reasoning about living things. However, it is not clear whether these domains are distinct for children; past work suggests that the 2 systems are confused until age 10, and that radical theory change accounts for eventual differentiation. To examine this claim, 16 subjects each at ages 6, 8, and adult were shown pictures of predatory and domestic animals and asked whether each animal displayed a variety of biological properties (e.g., has blood) and psychological properties (e.g., can think, can feel angry). Subjects at all ages showed clearly different attribution patterns for biological versus psychological properties. This dissociation of attribution patterns provides evidence that by kindergarten, notions of folkpsychology and folkbiology are sufficiently differentiated to constitute distinct and independent conceptual domains. This in turn suggests that radical theory change regarding living things either occurs prior to the beginning of formal education, or does not explain the development of folkbiological knowledge.

  2. Soil Physicochemical and Biological Properties of Paddy-Upland Rotation: A Review

    PubMed Central

    Lv, Teng-Fei; Chen, Yong; Westby, Anthony P.; Ren, Wan-Jun

    2014-01-01

    Paddy-upland rotation is an unavoidable cropping system for Asia to meet the increasing demand for food. The reduction in grain yields has increased the research interest on the soil properties of rice-based cropping systems. Paddy-upland rotation fields are unique from other wetland or upland soils, because they are associated with frequent cycling between wetting and drying under anaerobic and aerobic conditions; such rotations affect the soil C and N cycles, make the chemical speciation and biological effectiveness of soil nutrient elements varied with seasons, increase the diversity of soil organisms, and make the soil physical properties more difficult to analyze. Consequently, maintaining or improving soil quality at a desirable level has become a complicated issue. Therefore, fully understanding the soil characteristics of paddy-upland rotation is necessary for the sustainable development of the system. In this paper, we offer helpful insight into the effect of rice-upland combinations on the soil chemical, physical, and biological properties, which could provide guidance for reasonable cultivation management measures and contribute to the improvement of soil quality and crop yield. PMID:24995366

  3. Changes in optical properties of biological tissue: experiment and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Kaspar, Pavel; Prokopyeva, Elena; Tománek, Pavel; Grmela, Lubomír.

    2016-12-01

    Biological tissue is a very complex, yet important material to describe and analyze. Its properties are affected by chemical processes too numerous to easily understand and describe. By simplifying and grouping some aspects together we are able to create a model for simulating behavior of a photon inside of a biological sample. Using the Monte Carlo method an algorithm for calculating photon propagation through the tissue based on several optical parameters, like absorption and scattering coefficients, refractive indices and optical anisotropy, can be created. Based on some of the results of the simulation a comparative measurement on a muscle sample was performed to prove the usefulness of such model and to describe changes in the tissue sample based on the aforementioned optical parameters in both real life and the simulation.

  4. Characterization of the structure of ultra dilute sols with remarkable biological properties.

    PubMed

    Rao, Manju Lata; Roy, Rustum; Bell, Iris

    2008-04-15

    Most natural waters are probably "ultra dilute": aquasols. While the composition of such waters is routinely characterized thoroughly with respect to composition, very little attention has been paid to the solid phases which are certainly suspended in most, if not all, such. Our recent work having established the importance of the structure of water on its properties, [[1]; R. Roy, W.A. Tiller, I. Bell, M.R. Hoover; Mater Res Innov. 9 (2005) 577.] we have examined the structures of many waters with easily demonstrated (e.g. silver aquasols) or long-claimed (e.g. homeopathic remedies) biological effects. The results show that such materials can be easily distinguished from the pure solvent, and from each other, by the use of UV-VIS and Raman spectroscopy, while FTIR is insensitive to these differences. This opens up a whole new field of endeavor for inorganic materials scientists interested in biological effects.

  5. Biological processes, properties and molecular wiring diagrams of candidate low-penetrance breast cancer susceptibility genes

    PubMed Central

    Bonifaci, Núria; Berenguer, Antoni; Díez, Javier; Reina, Oscar; Medina, Ignacio; Dopazo, Joaquín; Moreno, Víctor; Pujana, Miguel Angel

    2008-01-01

    Background Recent advances in whole-genome association studies (WGASs) for human cancer risk are beginning to provide the part lists of low-penetrance susceptibility genes. However, statistical analysis in these studies is complicated by the vast number of genetic variants examined and the weak effects observed, as a result of which constraints must be incorporated into the study design and analytical approach. In this scenario, biological attributes beyond the adjusted statistics generally receive little attention and, more importantly, the fundamental biological characteristics of low-penetrance susceptibility genes have yet to be determined. Methods We applied an integrative approach for identifying candidate low-penetrance breast cancer susceptibility genes, their characteristics and molecular networks through the analysis of diverse sources of biological evidence. Results First, examination of the distribution of Gene Ontology terms in ordered WGAS results identified asymmetrical distribution of Cell Communication and Cell Death processes linked to risk. Second, analysis of 11 different types of molecular or functional relationships in genomic and proteomic data sets defined the "omic" properties of candidate genes: i/ differential expression in tumors relative to normal tissue; ii/ somatic genomic copy number changes correlating with gene expression levels; iii/ differentially expressed across age at diagnosis; and iv/ expression changes after BRCA1 perturbation. Finally, network modeling of the effects of variants on germline gene expression showed higher connectivity than expected by chance between novel candidates and with known susceptibility genes, which supports functional relationships and provides mechanistic hypotheses of risk. Conclusion This study proposes that cell communication and cell death are major biological processes perturbed in risk of breast cancer conferred by low-penetrance variants, and defines the common omic properties, molecular

  6. Effect of nanoclay addition on physical, chemical, optical and biological properties of experimental dental resin composites.

    PubMed

    Munhoz, Tais; Fredholm, Yann; Rivory, Pascaline; Balvay, Sandra; Hartmann, Daniel; da Silva, Pedro; Chenal, Jean-Marc

    2017-03-01

    To prepare organically modified montmorillonite (OM MMT) and assess mechanical, physical, chemical and biological effects of its introduction into resin-composites. Natural MMT clay was modified by a methacrylate functionalized quaternary ammonium intercalating agent. Interlayer distance was measured by X-ray diffraction. Dental composites were then prepared with x=0, 1, 2.5, 5 or 7.5wt.% of OM MMT, (75-x) wt.% of silanated barium glass and 25wt.% of methacrylate based matrix). Relative weight loss was measured and the effect of the substitution on mechanical properties was studied by dynamic mechanical analysis and hardness tests. Properties of resin composites were evaluated in terms of water sorption, light transmittance, biological tests and by high-performance liquid chromatography (HPLC). Resin based composites with well-dispersed organically modified MMT were successfully prepared. There were no significant weight loss differences shown by TGA within all samples. The DMA analysis showed that the introduction of clays have a beneficial effect in increasing the storage and elastic modulus of composites. Clay presence was shown to interfere with the blue light transmittance, affecting Vickers hardness and water sorption levels. The amount of released monomers measured from extracts was below expected levels for this type of materials and biological tests show satisfactory cell compatibility. This paper reports the successful functionalization of MMT by a methacrylate group and further incorporation in experimental dental composites. Physical and biological results show a potential interest to the application of nanoclays into dental resin composites. Copyright © 2016. Published by Elsevier Ltd.

  7. Nanoparticle size and surface properties determine the protein corona with possible implications for biological impacts

    PubMed Central

    Lundqvist, Martin; Stigler, Johannes; Elia, Giuliano; Lynch, Iseult; Cedervall, Tommy; Dawson, Kenneth A.

    2008-01-01

    Nanoparticles in a biological fluid (plasma, or otherwise) associate with a range of biopolymers, especially proteins, organized into the “protein corona” that is associated with the nanoparticle and continuously exchanging with the proteins in the environment. Methodologies to determine the corona and to understand its dependence on nanomaterial properties are likely to become important in bionanoscience. Here, we study the long-lived (“hard”) protein corona formed from human plasma for a range of nanoparticles that differ in surface properties and size. Six different polystyrene nanoparticles were studied: three different surface chemistries (plain PS, carboxyl-modified, and amine-modified) and two sizes of each (50 and 100 nm), enabling us to perform systematic studies of the effect of surface properties and size on the detailed protein coronas. Proteins in the corona that are conserved and unique across the nanoparticle types were identified and classified according to the protein functional properties. Remarkably, both size and surface properties were found to play a very significant role in determining the nanoparticle coronas on the different particles of identical materials. We comment on the future need for scientific understanding, characterization, and possibly some additional emphasis on standards for the surfaces of nanoparticles. PMID:18809927

  8. Electrostatically self-assembled biodegradable microparticles from pseudoproteins and polysaccharide: fabrication, characterization, and biological properties.

    PubMed

    Potuck, Alicia N; Weed, Beth L; Leifer, Cynthia A; Chu, C C

    2015-02-09

    Electrostatically self-assembling hybrid microparticles derived from novel cationic unsaturated arginine-based poly(ester amide) polymers (UArg-PEA) and anionic hyaluronic acid (HA) were fabricated into sub-micron-sized particles in aqueous medium with subsequent UV crosslinking treatment to stabilize the structure. These hybrid microparticles were characterized for size, charge, viscosity, chemical structure, morphology, and biological properties. Depending on the feed ratio of cationic UArg-PEA to anionic HA, the crosslinked microparticles formed spherical structures of 0.772-22.08 μm in diameter, whereas the uncrosslinked microparticles formed a core with an outer petal-like structure of 2.49-15 μm in diameter. It was discovered that the morphological structure of the self-assembled microparticles had a profound influence on their biological properties. At a 1:1 feed ratio of UArg-PEA to HA, the uncrosslinked microparticles showed no cytotoxicity toward NIH 3T3 fibroblasts at concentrations up to 20 μg/mL, and the crosslinked particles exhibited no cytotoxicity at concentrations up to 10 μg/mL. The UArg-PEA/HA hybrid microparticles exhibited a significantly lower macrophage-induced proinflammatory response (via TNF-α) than that from a pure hyaluronic acid control while retaining the beneficial anti-inflammatory IL-10 production by HA. The UArg-PEA/HA microparticles also stimulated size-dependent induction of arginase activity. Therefore, self-assembling these two types of biomaterials in a favorable nontoxic aqueous environment, having complementary biological properties like those of the currently reported UArg-PEA/HA hybrid microparticles, may provide a new class of biomaterials to improve the overall tissue microenvironment for promoting wound healing.

  9. The chemical composition and biological properties of coconut (Cocos nucifera L.) water.

    PubMed

    Yong, Jean W H; Ge, Liya; Ng, Yan Fei; Tan, Swee Ngin

    2009-12-09

    Coconut water (coconut liquid endosperm), with its many applications, is one of the world's most versatile natural product. This refreshing beverage is consumed worldwide as it is nutritious and beneficial for health. There is increasing scientific evidence that supports the role of coconut water in health and medicinal applications. Coconut water is traditionally used as a growth supplement in plant tissue culture/micropropagation. The wide applications of coconut water can be justified by its unique chemical composition of sugars, vitamins, minerals, amino acids and phytohormones. This review attempts to summarise and evaluate the chemical composition and biological properties of coconut water.

  10. Specific features of diffuse photon migration in highly scattering media with optical properties of biological tissues

    SciTech Connect

    Proskurin, S G; Potlov, A Yu; Frolov, S V

    2015-06-30

    Specific features of motion of photon density normalised maximum (PDNM) of pulsed radiation in highly scattering media with optical properties of biological tissues are described. A numerical simulation has confirmed that, when the object is a homogeneous cylinder, PDNM always moves to its geometric centre. In the presence of an absorbing inhomogeneity, PDNM moves towards the point symmetric to the geometric centre of the inhomogeneity with respect to the centre of the cylindrical object. In the presence of a scattering inhomogeneity, PDNM moves towards its geometric centre. (radiation scattering)

  11. [BIOLOGICAL PROPERTIES OF SALMONELLA, ISOLATED FROM CLINICAL MATERIAL AND AQUATIC ENVIRONMENT IN ROSTOV REGION].

    PubMed

    Panasovets, O P; Usatkin, A V; Shmailenko, O A

    2015-01-01

    Study biological properties of salmonella, isolated from clinical materials and water of Don river. Salmonella strains of various serovars were used in the study. Biochemical characteristics were studied by generally accepted methods, antigenic properties were evaluated in agglutination reactions, virulence was determined by Dlm for laboratory animals, antibiotics sensitivity was verified by disc-diffusion method. The presence of pathogenicity factors in isolated strains was shown: hemolytic activity--in 64 and 36.8% of cases, DNAse activity--in 28 and 26%, respectively in clinical and wild strains. Microorganism dose, resulting in death of all the animals (LD100) did not depend on serovar of salmonella and varied from 10(3) to 10(10) PFU/ml. Clinical strains were established to possess higher virulence and resistance to antibiotics compared with strains isolated from the aquatic envionment.

  12. The influence of fluorine, boron, selenium, and arsenic pollution on the biological properties of ordinary chernozems

    NASA Astrophysics Data System (ADS)

    Kolesnikov, S. I.; Popovich, A. A.; Kazeev, K. Sh.; Val'Kov, V. F.

    2008-04-01

    In most cases, fluorine, boron, selenium, and arsenic pollution deteriorates the ecological-biological properties of ordinary chernozems: the number of saprotrophic bacteria (especially those of the Azotobacter genus) that of fungi, and the enzymatic activity decreases, while the phytotoxicity becomes higher, etc. The consequences of this pollution are related to the nature of the element, its concentration in the soil, the chemical form of the compound, and the time period from the moment of pollution. The elements studied form the following sequences according to their effect on the properties of an ordinary chernozem: B > Se > As > F (when the maximum permissible concentration (MPS) of these elements was accepted as the unit of measure) and Se > As > B > F (when the units of measurement were mg/kg or mmol/kg of soil).

  13. The effect of fibronectin on structural and biological properties of single walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Atyabi, Fatemeh; Omidvar, Ramin; Shokrgozar, Mohammad Ali; Sadeghizadeh, Majid

    2015-06-01

    Despite the attractive properties of carbon nanotubes (CNTs), cytoxicity and hydrophobicity are two main considerable features which limit their application in biomedical fields. It was well established that treating CNTs with extracellular matrix components could reduce these unfavourable characteristics. In an attempt to address these issues, fibronectin (FN) with different concentrations was loaded on single walled carbon nanotubes (SWCNTs) substrate. Scanning electron microscope, atomic force microscopy (AFM), contact angles and X-ray photoelectron spectroscopy (XPS) were preformed in order to characterize FN loaded SWCNTs substrates. According to XPS and AFM results, FN could interact with SWCNTs and for this, the hydrophilicity of SWCNTs was improved. Additionally, SWCNT modified with FN showed less cytotoxicity compared with neat SWCNT. Finally, FN was shown to act as an interesting extracellular component for enhancing the biological properties of SWCNT.

  14. Gastropod nacre: structure, properties and growth--biological, chemical and physical basics.

    PubMed

    Heinemann, Fabian; Launspach, Malte; Gries, Katharina; Fritz, Monika

    2011-01-01

    The biogenic polymer/mineral composite nacre is a non-brittle biological ceramic, which self-organizes in aqueous environment and under ambient conditions. It is therefore an important model for new sustainable materials. Its highly controlled structural organization of mineral and organic components at all scales down to the nano- and molecular scales is guided by organic molecules. These molecules then get incorporated into the material to be responsible for properties like fracture mechanics, beauty and corrosion resistance. We report here on structure, properties and growth of columnar (gastropod) nacre with emphasis on the genus Haliotis in contrast to sheet nacre of many bivalves. © 2010 Elsevier B.V. All rights reserved.

  15. A few nascent methods for measuring mechanical properties of the biological cell.

    SciTech Connect

    Thayer, Gayle Echo; de Boer, Maarten Pieter; Corvalan, Carlos; Corwin, Alex David; Campanella, Osvaldo H. (Purdue University, West Lafayette, IN); Nivens, David (Purdue University, West Lafayette, IN); Werely, Steven (Purdue University, West Lafayette, IN); Sumali, Anton Hartono; Koch, Steven John

    2006-01-01

    This report summarizes a survey of several new methods for obtaining mechanical and rheological properties of single biological cells, in particular: (1) The use of laser Doppler vibrometry (LDV) to measure the natural vibrations of certain cells. (2) The development of a novel micro-electro-mechanical system (MEMS) for obtaining high-resolution force-displacement curves. (3) The use of the atomic force microscope (AFM) for cell imaging. (4) The adaptation of a novel squeezing-flow technique to micro-scale measurement. The LDV technique was used to investigate the recent finding reported by others that the membranes of certain biological cells vibrate naturally, and that the vibration can be detected clearly with recent instrumentation. The LDV has been reported to detect motions of certain biological cells indirectly through the motion of a probe. In this project, trials on Saccharomyces cerevisiae tested and rejected the hypothesis that the LDV could measure vibrations of the cell membranes directly. The MEMS investigated in the second technique is a polysilicon surface-micromachined force sensor that is able to measure forces to a few pN in both air and water. The simple device consists of compliant springs with force constants as low as 0.3 milliN/m and Moire patterns for nanometer-scale optical displacement measurement. Fields from an electromagnet created forces on magnetic micro beads glued to the force sensors. These forces were measured and agreed well with finite element prediction. It was demonstrated that the force sensor was fully functional when immersed in aqueous buffer. These results show the force sensors can be useful for calibrating magnetic forces on magnetic beads and also for direct measurement of biophysical forces on-chip. The use of atomic force microscopy (AFM) for profiling the geometry of red blood cells was the third technique investigated here. An important finding was that the method commonly used for attaching the cells to a

  16. Effect of methoxy group position on biological properties of (18)F-labeled benzyl triphenylphosphonium cations.

    PubMed

    Chen, Shuting; Zhao, Zuoquan; Zhang, Ying; Fang, Wei; Lu, Jie; Zhang, Xianzhong

    2017-06-01

    (18)F-labeled phosphonium cations targeting mitochondrial membrane potential would be promising for positron emission tomography (PET) myocardial perfusion imaging (MPI). The purpose of this study was to examine the influence of additional methoxy group and its different positions on myocardium uptake and pharmacokinetics properties of (18)F-labeled benzyl triphenylphosphonium cations. In this study, three novel (18)F-labeled phosphonium cations, [(18)F]4-(fluoromethyl)benzyltris(4-methoxyphenyl) phosphonium cation (1b), [(18)F]4-(fluoromethyl)benzyltris(2-methoxyphenyl) phosphonium cation (2b) and [(18)F]4-(fluoromethyl)benzyltris(3-methoxyphenyl) phosphonium cation (3b), were efficiently prepared by a One-Pot method starting from the substitution of non-carried-added fluoride-18. Radiotracers were purified by HPLC. Physicochemical properties, in vitro cell uptake assay, in vivo mice biodistribution and rat micro-PET imaging were investigated. Results suggested that the position of methoxy group exhibited significant effect on the biological properties of (18)F-labeled benzyl triphenylphosphonium cations. The addition of methoxy group on orth- or meta-position of the radiotracers accelerated the radioactivity clearance from liver. The para-radiotracer had the highest uptake in the heart and other non-targeting organs. According to the biodistribution data, 2b (ortho-) displayed the fastest liver clearance and highest heart-to-background ratios. And its rat micro-PET images at 60min post-injection revealed a good visualization of heart and favorable heart-to-background contrast. Nevertheless, 2b exhibited a lower initial liver uptake and quicker liver clearance compared with (99m)Tc-sestamibi. The ortho- compound (2b) displayed the most favorable biological properties as a potential MPI agent to acquire high contrast images early after injection. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Mechanical properties and structure of the biological multilayered material system, Atractosteus spatula scales.

    PubMed

    Allison, P G; Chandler, M Q; Rodriguez, R I; Williams, B A; Moser, R D; Weiss, C A; Poda, A R; Lafferty, B J; Kennedy, A J; Seiter, J M; Hodo, W D; Cook, R F

    2013-02-01

    During recent decades, research on biological systems such as abalone shell and fish armor has revealed that these biological systems employ carefully arranged hierarchical multilayered structures to achieve properties of high strength, high ductility and light weight. Knowledge of such structures may enable pathways to design bio-inspired materials for various applications. This study was conducted to investigate the spatial distribution of structure, chemical composition and mechanical properties in mineralized fish scales of the species Atractosteus spatula. Microindentation tests were conducted, and cracking patterns and damage sites in the scales were examined to investigate the underlying protective mechanisms of fish scales under impact and penetration loads. A difference in nanomechanical properties was observed, with a thinner, stiffer and harder outer layer (indentation modulus ∼69 GPa and hardness ∼3.3 GPa) on a more compliant and thicker inner layer (indentation modulus ∼14.3 GPa and hardness ∼0.5 GPa). High-resolution scanning electron microscopy imaging of a fracture surface revealed that the outer layer contained oriented nanorods embedded in a matrix, and that the nanostructure of the inner layer contained fiber-like structures organized in a complex layered pattern. Damage patterns formed during microindentation show complex deformation mechanisms. Images of cracks identify growth through the outer layer, then deflection along the interface before growing and arresting in the inner layer. High-magnification images of the crack tip in the inner layer show void-linking and fiber-bridging exhibiting inelastic behavior. The observed difference in mechanical properties and unique nanostructures of different layers may have contributed to the resistance of fish scales to failure by impact and penetration loading. Published by Elsevier Ltd.

  18. Biochemical and Biological Characterization of a New Oxidized Avidin with Enhanced Tissue Binding Properties

    PubMed Central

    Verdoliva, Antonio; Bellofiore, Piero; Rivieccio, Vincenzo; Catello, Sergio; Colombo, Maurizio; Albertoni, Claudio; Rosi, Antonio; Leoni, Barbara; Anastasi, Anna Maria; De Santis, Rita

    2010-01-01

    Chicken avidin and bacterial streptavidin are widely employed in vitro for their capacity to bind biotin, but their pharmacokinetics and immunological properties are not always optimal, thereby limiting their use in medical treatments. Here we investigate the biochemical and biological properties of a new modified avidin, obtained by ligand-assisted sodium periodate oxidation of avidin. This method allows protection of biotin-binding sites of avidin from inactivation caused by the oxidation step and delay of avidin clearance from injected tissue by generation of aldehyde groups from avidin carbohydrate moieties. Oxidized avidin shows spectroscopic properties similar to that of native avidin, indicating that tryptophan residues are spared from oxidation damage. In strict agreement with these results, circular dichroism and isothermal titration calorimetry analyses confirm that the ligand-assisted oxidation preserves the avidin protein structure and its biotin binding capacity. In vitro cell binding and in vivo tissue residence experiments demonstrate that aldehyde groups provide oxidized avidin the property to bind cellular and interstitial protein amino groups through Schiff's base formation, resulting in a tissue half-life of 2 weeks, compared with 2 h of native avidin. In addition, the efficient uptake of the intravenously injected 111In-BiotinDOTA (ST2210) in the site previously treated with modified avidin underlines that tissue-bound oxidized avidin retains its biotin binding capacity in vivo. The results presented here indicate that oxidized avidin could be employed to create a stable artificial receptor in diseased tissues for the targeting of biotinylated therapeutics. PMID:20100839

  19. Extruded collagen fibres for tissue engineering applications: effect of crosslinking method on mechanical and biological properties.

    PubMed

    Enea, Davide; Henson, Frances; Kew, Simon; Wardale, John; Getgood, Alan; Brooks, Roger; Rushton, Neil

    2011-06-01

    Reconstituted collagen fibres are promising candidates for tendon and ligament tissue regeneration. The crosslinking procedure determines the fibres' mechanical properties, degradation rate, and cell-fibre interactions. We aimed to compare mechanical and biological properties of collagen fibres resulting from two different types of crosslinking chemistry based on 1-ethyl-3-(3-dimethyllaminopropyl)carbodiimide (EDC). Fibres were crosslinked with either EDC or with EDC and ethylene-glycol-diglycidyl-ether (EDC/EGDE). Single fibres were mechanically tested to failure and bundles of fibres were seeded with tendon fibroblasts (TFs) and cell attachment and proliferation were determined over 14 days in culture. Collagen type I and tenascin-C production were assessed by immunohistochemistry and dot-blotting. EDC chemistry resulted in fibres with average mechanical properties but the highest cell proliferation rate and matrix protein production. EDC/EGDE chemistry resulted in fibres with improved mechanical properties but with a lower biocompatibility profile. Both chemistries may provide useful structures for scaffolding regeneration of tendon and ligament tissue and will be evaluated for in vivo tendon regeneration in future experiments.

  20. Effect of chain elongation on biological properties of the toxin paralysin β-alanyl-tyrosine.

    PubMed

    Macurkova, Anna; Neubauerova, Tereza; Poncova, Kristyna; Jezek, Rudolf; Lovecka, Petra; Spiwok, Vojtech; Mackova, Martina; Macek, Tomas

    2014-04-01

    In hemolymph of insect species, compounds with remarkable properties for pharmaceutical industry are present. At the first line, there were found compounds of low molecular mass, less than 1 kDa. One of such compounds, β-alanyl-tyrosine (252 Da), was isolated from larval hemolymph of some species of holometabolous insects (e.g. Neobellieria bullata). Its paralytic activity and antimicrobial properties were described until now. In this study, we present the effect of elongation of β-alanyl-tyrosine by repeating of this motive on the biological and physical properties of prepared analogues. For assessment of antimicrobial properties of these new compounds strains of Gram-positive, Gram-negative bacteria and fungi were used, we also followed the haemolytic activity and toxic effect on human cell culture HepG2. On the base of ECD spectroscopy measurement, subsequent molecular modelling and known secondary structure of original β-alanyl-tyrosine dipeptide, the secondary structures of repeating sequences of β-AY were specified. The repeating structures of β-alanyl-tyrosine show increase in antimicrobial activity; for Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, minimal inhibitory concentration was decreased from 30 to 15 mM for 2xβ-AY, 0.4 mM for 4xβ-AY and 0.25 mM for 6xβ-AY.

  1. Functional groups affect physical and biological properties of dextran-based hydrogels.

    PubMed

    Sun, Guoming; Shen, Yu-I; Ho, Chia Chi; Kusuma, Sravanti; Gerecht, Sharon

    2010-06-01

    Modification of dextran backbone allows the development of a hydrogel with specific characteristics. To enhance their functionality for tissue-engineered scaffolds, a series of dextran-based macromers was synthesized by incorporating various functional groups, including allyl isocyanate (Dex-AI), ethylamine (Dex-AE), chloroacetic acid (Dex-AC), or maleic-anhydride (Dex-AM) into dextrans. The dextran-based biodegradable hybrid hydrogels are developed by integrating polyethylene glycol diacrylate (PEGDA). To explore the effect of different derivatives on hydrogel properties, three different ratios of Dex/PEGDA are examined: low (20/80), medium (40/60), and high (60/40). Differences in physical and biological properties of the hydrogels are found, including swelling, degradation rate, mechanics, crosslinking density, biocompatibility (in vitro and in vivo), and vascular endothelial growth factor release. The results also indicate that the incorporation of amine groups into dextran gives rise to hydrogels with better biocompatible and release properties. We, therefore, conclude that the incorporation of different functional groups affects the fundamental properties of a dextran-based hydrogel network, and that amine groups are preferred to generate hydrogels for biomedical use.

  2. Synthesis and biological activities of dynorphin A analogues with opioid antagonist properties.

    PubMed

    Gairin, J E; Mazarguil, H; Alvinerie, P; Saint-Pierre, S; Meunier, J C; Cros, J

    1986-10-01

    Dynorphin A, which displays a wide variety of physiological effects, binds to opioid receptors preferentially at the kappa receptor type. kappa-selective antagonists would be very useful as pharmacological and biochemical probes to study and better understand the action of dynorphin A at its preferred receptor. However, the development of such molecules has been elusive, and very few are known at this time. Taking these features into account, we have synthesized by the solid-phase procedure several analogues of dynorphin A containing various D-amino acid substitutions. The binding properties of the peptides have been examined at three main opioid binding sites (mu, delta, and kappa) and their kappa selectivity determined. Their biological activities have been tested in three specific pharmacological assays for agonist and/or antagonist properties. Introduction of D-Trp substitution leads to analogues, in particular [D- Trp2,8,D-Pro10]-, [D-Trp5,8,D-Pro10]-, and [D-Trp2,4,8,D-Pro10]dynorphin(1-11), showing antagonist properties in the isolated rabbit vas deferens preparation, a kappa specific bioassay. The antagonism against dynorphin A is weak, as indicated by the observed Ke values (433, 199, and 293 nM, respectively), and not very selective (kappa vs. mu). Such peptide analogues derived from the endogenous ligand and endowed with antagonist properties are the first ones reported to date and could open a promising way in designing more potent and selective kappa opioid antagonists.

  3. Improving mechanical and biological properties of macroporous HA scaffolds through composite coatings.

    PubMed

    Zhao, J; Lu, X; Duan, K; Guo, L Y; Zhou, S B; Weng, J

    2009-11-01

    Interconnected porous hydroxyapatite (HA) scaffolds are widely used for bone repair and replacement, owing to their ability to support the adhesion, transfer, proliferation and differentiation of cells. In the present study, the polymer impregnation approach was adopted to produce porous HA scaffolds with three-dimensional (3D) porous structures. These scaffolds have an advantage of highly interconnected porosity (approximately 85%) but a drawback of poor mechanical strength. Therefore, the as-prepared HA scaffolds were lined with composite polymer coatings in order to improve the mechanical properties and retain its good bioactivity and biocompatibility at the same time. The composite coatings were based on poly(D,L-lactide) (PDLLA) polymer solutions, and contained single component or combination of HA, calcium sulfate (CS) and chondroitin sulfate (ChS) powders. The effects of composite coatings on scaffold porosity, microstructure, mechanical property, in vitro mineralizing behavior, and cell attachment of the resultant scaffolds were investigated. The results showed that the scaffolds with composite coatings resulted in significant improvement in both mechanical and biological properties while retaining the 3D interconnected porous structure. The in vitro mineralizing behaviors were mainly related to the compositions of CS and ChS powders in the composite coatings. Excellent cell attachments were observed on the pure HA scaffold as well as the three types of composite scaffolds. These composite scaffolds with improved mechanical properties and bioactivities are promising bone substitutes in tissue engineering fields.

  4. Biochemical and biological characterization of a new oxidized avidin with enhanced tissue binding properties.

    PubMed

    Verdoliva, Antonio; Bellofiore, Piero; Rivieccio, Vincenzo; Catello, Sergio; Colombo, Maurizio; Albertoni, Claudio; Rosi, Antonio; Leoni, Barbara; Anastasi, Anna Maria; De Santis, Rita

    2010-03-19

    Chicken avidin and bacterial streptavidin are widely employed in vitro for their capacity to bind biotin, but their pharmacokinetics and immunological properties are not always optimal, thereby limiting their use in medical treatments. Here we investigate the biochemical and biological properties of a new modified avidin, obtained by ligand-assisted sodium periodate oxidation of avidin. This method allows protection of biotin-binding sites of avidin from inactivation caused by the oxidation step and delay of avidin clearance from injected tissue by generation of aldehyde groups from avidin carbohydrate moieties. Oxidized avidin shows spectroscopic properties similar to that of native avidin, indicating that tryptophan residues are spared from oxidation damage. In strict agreement with these results, circular dichroism and isothermal titration calorimetry analyses confirm that the ligand-assisted oxidation preserves the avidin protein structure and its biotin binding capacity. In vitro cell binding and in vivo tissue residence experiments demonstrate that aldehyde groups provide oxidized avidin the property to bind cellular and interstitial protein amino groups through Schiff's base formation, resulting in a tissue half-life of 2 weeks, compared with 2 h of native avidin. In addition, the efficient uptake of the intravenously injected (111)In-BiotinDOTA (ST2210) in the site previously treated with modified avidin underlines that tissue-bound oxidized avidin retains its biotin binding capacity in vivo. The results presented here indicate that oxidized avidin could be employed to create a stable artificial receptor in diseased tissues for the targeting of biotinylated therapeutics.

  5. Food-grade nanoemulsions: formulation, fabrication, properties, performance, biological fate, and potential toxicity.

    PubMed

    McClements, David Julian; Rao, Jiajia

    2011-04-01

    Nanoemulsions fabricated from food-grade ingredients are being increasingly utilized in the food industry to encapsulate, protect, and deliver lipophilic functional components, such as biologically-active lipids (e.g., ω-3 fatty acids, conjugated linoleic acid) and oil-soluble flavors, vitamins, preservatives, and nutraceuticals. The small size of the particles in nanoemulsions (r<100 nm) means that they have a number of potential advantages over conventional emulsions-higher stability to droplet aggregation and gravitational separation, high optical clarity, ability to modulate product texture, and, increased bioavailability of lipophilic components. On the other hand, there may also be some risks associated with the oral ingestion of nanoemulsions, such as their ability to change the biological fate of bioactive components within the gastrointestinal tract and the potential toxicity of some of the components used in their fabrication. This review article provides an overview of the current status of nanoemulsion formulation, fabrication, properties, applications, biological fate, and potential toxicity with emphasis on systems suitable for utilization within the food and beverage industry. © Taylor and Francis Group, LLC

  6. Golden Needle Mushroom: A Culinary Medicine with Evidenced-Based Biological Activities and Health Promoting Properties.

    PubMed

    Tang, Calyn; Hoo, Pearl Ching-Xin; Tan, Loh Teng-Hern; Pusparajah, Priyia; Khan, Tahir Mehmood; Lee, Learn-Han; Goh, Bey-Hing; Chan, Kok-Gan

    2016-01-01

    Flammulina velutipes (enoki, velvet shank, golden needle mushroom or winter mushroom), one of the main edible mushrooms on the market, has long been recognized for its nutritional value and delicious taste. In recent decades, research has expanded beyond detailing its nutritional composition and delved into the biological activities and potential health benefits of its constituents. Many bioactive constituents from a range of families have been isolated from different parts of the mushroom, including carbohydrates, protein, lipids, glycoproteins, phenols, and sesquiterpenes. These compounds have been demonstrated to exhibit various biological activities, such as antitumour and anticancer activities, anti-atherosclerotic and thrombosis inhibition activity, antihypertensive and cholesterol lowering effects, anti-aging and antioxidant properties, ability to aid with restoring memory and overcoming learning deficits, anti-inflammatory, immunomodulatory, anti-bacterial, ribosome inactivation and melanosis inhibition. This review aims to consolidate the information concerning the phytochemistry and biological activities of various compounds isolated from F. velutipes to demonstrate that this mushroom is not only a great source of nutrients but also possesses tremendous potential in pharmaceutical drug development.

  7. Golden Needle Mushroom: A Culinary Medicine with Evidenced-Based Biological Activities and Health Promoting Properties

    PubMed Central

    Tang, Calyn; Hoo, Pearl Ching-Xin; Tan, Loh Teng-Hern; Pusparajah, Priyia; Khan, Tahir Mehmood; Lee, Learn-Han; Goh, Bey-Hing; Chan, Kok-Gan

    2016-01-01

    Flammulina velutipes (enoki, velvet shank, golden needle mushroom or winter mushroom), one of the main edible mushrooms on the market, has long been recognized for its nutritional value and delicious taste. In recent decades, research has expanded beyond detailing its nutritional composition and delved into the biological activities and potential health benefits of its constituents. Many bioactive constituents from a range of families have been isolated from different parts of the mushroom, including carbohydrates, protein, lipids, glycoproteins, phenols, and sesquiterpenes. These compounds have been demonstrated to exhibit various biological activities, such as antitumour and anticancer activities, anti-atherosclerotic and thrombosis inhibition activity, antihypertensive and cholesterol lowering effects, anti-aging and antioxidant properties, ability to aid with restoring memory and overcoming learning deficits, anti-inflammatory, immunomodulatory, anti-bacterial, ribosome inactivation and melanosis inhibition. This review aims to consolidate the information concerning the phytochemistry and biological activities of various compounds isolated from F. velutipes to demonstrate that this mushroom is not only a great source of nutrients but also possesses tremendous potential in pharmaceutical drug development. PMID:28003804

  8. Imaging electric properties of biological tissues by RF field mapping in MRI.

    PubMed

    Zhang, Xiaotong; Zhu, Shanan; He, Bin

    2010-02-01

    The electric properties (EPs) of biological tissue, i.e., the electric conductivity and permittivity, can provide important information in the diagnosis of various diseases. The EPs also play an important role in specific absorption rate calculation, a major concern in high-field MRI, as well as in nonmedical areas such as wireless telecommunications. The high-field MRI system is accompanied by significant wave propagation effects, and the RF radiation is dependent on the EPs of biological tissue. On the basis of the measurement of the active transverse magnetic component of the applied RF field (known as B(1)-mapping technique), we propose a dual-excitation algorithm, which uses two sets of measured B(1) data to noninvasively reconstruct the EPs of biological tissues. The finite-element method was utilized in 3-D modeling and B(1) field calculation. A series of computer simulations were conducted to evaluate the feasibility and performance of the proposed method on a 3-D head model within a TEM coil and a birdcage coil. Using a TEM coil, when noise free, the reconstructed EP distribution of tissues in the brain has relative errors of 12%-28% and correlated coefficients of greater than 0.91. Compared with other B(1)-mapping-based reconstruction algorithms, our approach provides superior performance without the need for iterative computations. The present simulation results suggest that good reconstruction of EPs from B1 mapping can be achieved.

  9. Bioavailability, antioxidant and biological properties of the natural free-radical scavengers cyanidin and related glycosides.

    PubMed

    Galvano, Fabio; La Fauci, Luca; Vitaglione, Paola; Fogliano, Vincenzo; Vanella, Luca; Felgines, Catherine

    2007-01-01

    Cyanidin and its glycosides (Cy and Cyg) have been indicated as promising candidates as dietary compounds with a potential role in human health. They are the largest class of water-soluble compounds in plants, where they are responsible for the brilliant color (red, orange, blue) of fruits and flowers. As natural compounds of several foods such as vegetables, fruits and red wines, they are estimated to be widely ingested by humans. This paper, basing on the data previously reviewed in 2002, focuses on the findings regarding human and animal studies on Cy and Cyg absorption and metabolism, antioxidant activity and biological properties, with particular attention to anticarcinogenic activity, vasoprotective, anti-inflammatory, anti-obesity and anti-diabetes effects. It is concluded that although Cy and Cyg bioavailability is low, further investigations are necessary because some important metabolites may still not have been identified. Literature data on antioxidant activity and biological properties, however, widely confirm Cy and Cyg as dietary compounds with a potential beneficial role in human health.

  10. Biocorrosion properties of antibacterial Ti-10Cu sintered alloy in several simulated biological solutions.

    PubMed

    Liu, Cong; Zhang, Erlin

    2015-03-01

    Ti-10Cu sintered alloy has shown strong antibacterial properties against S. aureus and E. coli and good cell biocompatibility, which displays potential application in dental application. The corrosion behaviors of the alloy in five different simulated biological solutions have been investigated by electrochemical technology, surface observation, roughness measurement and immersion test. Five different simulated solutions were chosen to simulate oral condition, oral condition with F(-) ion, human body fluids with different pH values and blood system. It has been shown that Ti-10Cu alloy exhibits high corrosion rate in Saliva pH 3.5 solution and Saliva pH 6.8 + 0.2F solution but low corrosion rate in Hank's, Tyrode's and Saliva pH 6.8 solutions. The corrosion rate of Ti-10Cu alloy was in a order of Hank's, Tyrode's, Saliva pH 6.8, Saliva-pH 3.5 and Saliva pH 6.8 + 0.2F from slow to fast. All results indicated acid and F(-) containing conditions prompt the corrosion reaction of Ti-Cu alloy. It was suggested that the Cu ion release in the biological environments, especially in the acid and F(-) containing condition would lead to high antibacterial properties without any cell toxicity, displaying wide potential application of this alloy.

  11. Investigation of natural lipid-phenolic interactions on biological properties of virgin olive oil.

    PubMed

    Alu'datt, Muhammad H; Rababah, Taha; Ereifej, Khalil; Gammoh, Sana; Alhamad, Mohammad N; Mhaidat, Nizar; Kubow, Stan; Johargy, Ayman; Alnaiemi, Ola J

    2014-12-10

    There is limited knowledge regarding the impact of naturally occurring lipid-phenolic interactions on the biological properties of phenolics in virgin olive oil. Free and bound phenolics were isolated via sequential methanolic extraction at 30 and 60 °C, and were identified and quantified using reversed phase high performance liquid chromatography, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), and gas chromatography. Decreased oleic acid concentrations and increased concentrations of palmitoleic acid, stearic, linoleic, and linolenic acids were observed in virgin olive oil after removal of free and bound lipid phenolic compounds. The presence of p-hydroxybenzoic acid and tyrosol bound to glycerides was determined via LC-MS/MS, which indicates natural lipid-phenolic interactions in virgin olive oil. Both free and lipid bound phenolic extracts exerted antiproliferative activities against the CRC1 and CRC5 colorectal cancer cell lines. The present work indicates that naturally occurring lipid-phenolic interactions can affect the biological properties of phenolics in virgin olive oil.

  12. [Effects of tillage methods on soil physicochemical properties and biological characteristics in farmland: A review].

    PubMed

    Li, Yu-jie; Wang, Hui; Zhao, Jian-ning; Huangfu, Chao-he; Yang, Dian-lin

    2015-03-01

    Tillage methods affect soil heat, water, nutrients and soil biology in different ways. Reasonable soil management system can not only improve physical and chemical properties of the soil, but also change the ecological process of farmland soil. Conservation tillage can improve the quality of the soil to different degrees. For example, no-tillage system can effectively improve soil enzyme activity. No tillage and subsoiling tillage can provide abundant resources for soil microbe' s growth and reproduction. No tillage, minimum tillage and other conservation tillage methods exert little disturbance to soil animals, and in turn affect the quantity and diversity of the soil animals as well as their population structure. Effects of different tillage methods on soil physical and chemical properties as well as biological characteristics were reviewed in this article, with the soil physical and chemical indices, enzyme activities, soil microbe diversity and soil animals under different tillage patterns analyzed. The possibility of soil quality restoration with appropriate tillage methods and the future research direction were pointed out.

  13. Wildfire effects on biological properties of soils in forest-steppe ecosystems of Russia

    NASA Astrophysics Data System (ADS)

    Maksimova, E.; Abakumov, E.

    2014-01-01

    Soils affected by forest wildfires in 2010 in Russia were studied on postfire and mature plots near the Togljatty city, Samara region. Soil biological properties and ash composition dynamics were investigated under the forest fire affect: a place of local forest fire, riding forest fire and unaffected site by fire-control (mature) during 3 yr of restoration. Soil samples were collected at 0-15 cm. Soil biological properties was measured by the fumigation method. The analytical data obtained shows that wildfires lead to serious changes in a soil profile and soil chemistry of upper horizons. Wildfires change a chemical composition of soil horizons and increase their ash-content. Fires lead to accumulation of biogenic elements' content (P and K) in the solum fine earth. Calcium content is increased as a result of fires that leads to an alkaline pH of the solum. The values of nutrients decreased as a result of leaching out with an atmospheric precipitation during the second year of restoration. Thus, when the upper horizons are burning the ash arriving on a soil surface enrich it with nutrients. The mature (unaffected by fire) soils is characterized by the greatest values of soil microbial biomass in the top horizon and, respectively, the bigger values of basal respiration whereas declining of the both parameters was revealed on postfire soils. Nevertheless this influence does not extend on depth more than 10 cm. Thus, fire affect on the soil were recognized in decreasing of microbiological activity.

  14. Can Carbon Nanotubes Deliver on Their Promise in Biology? Harnessing Unique Properties for Unparalleled Applications

    PubMed Central

    2016-01-01

    Carbon nanotubes (CNTs) are cylindrical sheets of hexagonally ordered carbon atoms, giving tubes with diameters on the order of a few nanometers and lengths typically in the micrometer range. They may be single- or multiwalled (SWCNTs and MWCNTs respectively). Since the seminal report of their synthesis in 1991, CNTs have fascinated scientists of all stripes. Physicists have been intrigued by their electrical, thermal, and vibrational potential. Materials scientists have worked on integrating them into ultrastrong composites and electronic devices, while chemists have been fascinated by the effects of curvature on reactivity and have developed new synthesis and purification techniques. However, to date no large-scale, real-life biotechnological CNT breakthrough has been industrially adopted and it is proving difficult to justify taking these materials forward into the clinic. We believe that these challenges are not the end of the story, but that a viable carbon nanotube biotechnology is one in which the unique properties of nanotubes bring about an effect that would be otherwise impossible. In this Outlook, we therefore seek to reframe the field by highlighting those biological applications in which the singular properties of CNTs provide some entirely new activity or biological effect as a pointer to “what could be”. PMID:27163049

  15. [Characterization of the biological properties of acid-treated chrysotile-asbestos fibers].

    PubMed

    Pylev, L N; Vasil'eva, L A; Stadnikova, N M; Smirnova, O V; Zubakova, L E; Vezentsev, A I; Gudkova, E A; Bakhtin, A I

    2006-01-01

    Boiling of chrysotile of the textile brand PRZh1-50 in concentrated hydrochloric acid for 10, 15, and 20 minutes gave rise to three chrysotile-asbestos samples. The content of MgO decreased from to 24, 19, and 9%, respectively. As compared with the baseline values, the number and force of positively charged electrical centers were less in the samples containing 24 and 19% MgO and more in the sample having 9% MgO; the negatively charged centers were present in the former two samples and absent in the third one. When the samples were intrapleurally administered to rats, their hemolytic activity, induction of active oxygen radicals, mutagenic activity (micronuclear test using murine bone marrow cells), and the frequency of mesotheliomas were less in the treated samples than in the baseline ones; but there were no differences between the treated samples. Thus, the altered physicochemical properties of the fibrillar surface of asbestos diminished its biological aggressiveness; however, increased treatment rates failed to lead to its further decrease. There was no relationship of the biological properties to the number and force of electric charges of the surface.

  16. Electronic properties of a cytosine decavanadate: toward a better understanding of chemical and biological properties of decavanadates.

    PubMed

    Bosnjaković-Pavlović, Nada; Spasojević-de Biré, Anne; Tomaz, Isabel; Bouhmaida, Nouzha; Avecilla, Fernando; Mioc, Ubavka B; Pessoa, João Costa; Ghermani, Nour Eddine

    2009-10-19

    We have synthesized and crystallized a cytosine-decavanadate compound, Na(3) [V(10)O(28)] (C(4)N(3)OH(5))(3)(C(4)N(3)OH(6))(3).10H(2)O, and its crystal structure has been determined from a single-crystal X-ray diffraction. A high resolution X-ray diffraction experiment at 210 K (in P1 space group phase) was carried out. The data were refined using a pseudo-atom multipole model to get the electron density and the electrostatic properties of the decavanadate-cytosine complex. Static deformation density maps and Atoms in Molecules (AIM) topological analysis were used for this purpose. To get insight into the reactivity of the decavanadate anion, we have determined the atomic net charges and the molecular electrostatic potential. Special attention was paid to the hydrogen bonding occurring in the solid state between the decavanadate anion and its environment. The comparison of the experimental electronic characteristics of the decavanadate anions to those found in literature reveals that this anion is a rigid entity conserving its intrinsic properties. This is of particular importance for the future investigations of the biological activities of the decavanadate anion.

  17. Physico-chemical properties and biological effects of diesel and biomass particles.

    PubMed

    Longhin, Eleonora; Gualtieri, Maurizio; Capasso, Laura; Bengalli, Rossella; Mollerup, Steen; Holme, Jørn A; Øvrevik, Johan; Casadei, Simone; Di Benedetto, Cristiano; Parenti, Paolo; Camatini, Marina

    2016-08-01

    Diesel combustion and solid biomass burning are the major sources of ultrafine particles (UFP) in urbanized areas. Cardiovascular and pulmonary diseases, including lung cancer, are possible outcomes of combustion particles exposure, but differences in particles properties seem to influence their biological effects. Here the physico-chemical properties and biological effects of diesel and biomass particles, produced under controlled laboratory conditions, have been characterized. Diesel UFP were sampled from a Euro 4 light duty vehicle without DPF fuelled by commercial diesel and run over a chassis dyno. Biomass UFP were collected from a modern automatic 25 kW boiler propelled by prime quality spruce pellet. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of both diesel and biomass samples showed aggregates of soot particles, but in biomass samples ash particles were also present. Chemical characterization showed that metals and PAHs total content was higher in diesel samples compared to biomass ones. Human bronchial epithelial (HBEC3) cells were exposed to particles for up to 2 weeks. Changes in the expression of genes involved in xenobiotic metabolism were observed after exposure to both UFP already after 24 h. However, only diesel particles modulated the expression of genes involved in inflammation, oxidative stress and epithelial-to-mesenchymal transition (EMT), increased the release of inflammatory mediators and caused phenotypical alterations, mostly after two weeks of exposure. These results show that diesel UFP affected cellular processes involved in lung and cardiovascular diseases and cancer. Biomass particles exerted low biological activity compared to diesel UFP. This evidence emphasizes that the study of different emission sources contribution to ambient PM toxicity may have a fundamental role in the development of more effective strategies for air quality improvement. Copyright © 2016 Elsevier Ltd. All rights

  18. A Novel Reticular Dermal Graft Leverages Architectural and Biological Properties to Support Wound Repair

    PubMed Central

    Dasgupta, Anouska; Orgill, Dennis; Galiano, Robert D.; Zelen, Charles M.; Huang, Yen-Chen; Chnari, Evangelia; Li, William W.

    2016-01-01

    Background: Acellular dermal matrices (ADMs) are frequently used in reconstructive surgery and as scaffolds to treat chronic wounds. The 3-dimensional architecture and extracellular matrix provide structural and signaling cues for repair and remodeling. However, most ADMs are not uniformly porous, which can lead to heterogeneous host engraftment. In this study, we hypothesized that a novel human reticular ADM (HR-ADM; AlloPatch Pliable, Musculoskeletal Transplant Foundation, Edison, N.J.) when aseptically processed would have a more open uniform structure with retention of biological components known to facilitate wound healing. Methods: The reticular and papillary layers were compared through histology and scanning electron microscopy. Biomechanical properties were assessed through tensile testing. The impact of aseptic processing was evaluated by comparing unprocessed with processed reticular grafts. In vitro cell culture on fibroblasts and endothelial cells were performed to showcase functional cell activities on HR-ADMs. Results: Aseptically processed HR-ADMs have an open, interconnected uniform scaffold with preserved collagens, elastin, glycosaminoglycans, and hyaluronic acid. HR-ADMs had significantly lower ultimate tensile strength and Young’s modulus versus the papillary layer, with a higher percentage elongation at break, providing graft flexibility. These preserved biological components facilitated fibroblast and endothelial cell attachment, cell infiltration, and new matrix synthesis (collagen IV, fibronectin, von Willebrand factor), which support granulation and angiogenic activities. Conclusions: The novel HR-ADMs provide an open, interconnected scaffold with native dermal mechanical and biological properties. Furthermore, aseptic processing retains key extracellular matrix elements in an organized framework and supports functional activities of fibroblasts and endothelial cells. PMID:27826469

  19. Modification of titanium alloys surface properties by plasma electrolytic oxidation (PEO) and influence on biological response.

    PubMed

    Echeverry-Rendón, Mónica; Galvis, Oscar; Aguirre, Robinson; Robledo, Sara; Castaño, Juan Guillermo; Echeverría, Félix

    2017-09-27

    Surface characteristics can mediate biological interaction improving or affecting the tissue integration after implantation of a biomaterial. Features such as topography, wettability, surface energy and chemistry can be key determinants for interactions between cells and materials. Plasma electrolytic oxidation (PEO) is a technique used to control this kind of parameters by the addition of chemical species and the production of different morphologies on the surfaces of titanium and its alloys. With the purpose to improve the biological response, surfaces of c.p titanium and Ti6Al4V were modified by using PEO. Different electrolytes, voltages, current densities and anodizing times were tested in order to obtain surfaces with different characteristics. The obtained materials were characterized by different techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow discharge optical emission spectroscopy (GDOES). Wettability of the obtained surfaces were measured and the corresponding surface energies were calculated. Superhydrophilic surfaces with contact angles of about 0 degrees were obtained without any other treatment but PEO and this condition in some cases remains stable after several weeks of anodizing; crystal phase composition (anatase-rutile) of the anodic surface appears to be critical for obtaining this property. Finally, in order to verify the biological effect of these surfaces, osteoblast were seeded on the samples. It was found that cell behavior improves as SFE (surface free energy) and coating porosity increases whereas it is affected negatively by roughness. Techniques for surface modification allow changes in the coatings such as surface energy, roughness and porosity. As a consequence of this, biological response can be altered. In this paper, surfaces of c.p Ti and Ti6Al4V were modified by using plasma electrolytic oxidation (PEO) in order to accelerate the cell adhesion process.

  20. Physical-chemical determinant properties of biological communities in continental semi-arid waters.

    PubMed

    da Rocha, Francisco Cleiton; de Andrade, Eunice Maia; Lopes, Fernando Bezerra; de Paula Filho, Francisco José; Filho, José Hamilton Costa; da Silva, Merivalda Doroteu

    2016-08-01

    Throughout human history, water has undergone changes in quality. This problem is more serious in dry areas, where there is a natural water deficit due to climatic factors. The aims of this study, therefore, were (i) to verify correlations between physical attributes, chemical attributes and biological metrics and (ii) from the biological attributes, to verify the similarity between different points of a body of water in a tropical semi-arid region. Samples were collected every 2 months, from July 2009 to July 2011, at seven points. Four physical attributes, five chemical attributes and four biological metrics were investigated. To identify the correlations between the physicochemical properties and the biological metrics, hierarchical cluster analysis (HCA) and canonical correlation analysis (CCA) were applied. Nine classes of phytoplankton were identified, with the predominance of species of cyanobacteria, and ten families of macroinvertebrates. The use of HCA resulted in the formation of three similar groups, showing that it was possible to reduce the number of sampling points when monitoring water quality with a consequent reduction in cost. Group I was formed from the waters at the high end of the reservoir (points P1, P2 and P3), group II by the waters from the middle third (points P4 and P5), and group III by the waters from the lower part of the reservoir (points P6 and P7). Richness of the phytoplanktons Cyanophyceae, Chorophyceae and Bacillariophyceae was the attribute which determined dissimilarity in water quality. Using CCA, it was possible to identify the spatial variability of the physicochemical attributes (TSS, TKN, nitrate and total phosphorus) that most influence the metrics of the macroinvertebrates and phytoplankton present in the water. Low macroinvertebrate diversity, with a predominance of indicator families for deterioration in water quality, and the composition of phytoplankton showing a predominance of cyanobacteria, suggests greater

  1. Physical, chemical, and biological properties of soil under soybean cultivation and at an adjacent rainforest in Amazonia

    Treesearch

    T.P. Beldini; R.C. Oliveira Junior; Michael Keller; P.B. de Camargo; P.M. Crill; A. Damasceno da Silva; D. Bentes dos Santos; D. Rocha de Oliveira

    2015-01-01

    Land-use change in the Amazon basin has occurred at an accelerated pace during the last decade, and it is important that the effects induced by these changes on soil properties are better understood. This study investigated the chemical, physical, and biological properties of soil in a field under cultivation of soy and rice, and at an adjacent primary rain forest....

  2. Biological and functional properties of proteolytic enzyme-modified egg protein by-products

    PubMed Central

    Pokora, Marta; Eckert, Ewelina; Zambrowicz, Aleksandra; Bobak, Łukasz; Szołtysik, Marek; Dąbrowska, Anna; Chrzanowska, Józefa; Polanowski, Antoni; Trziszka, Tadeusz

    2013-01-01

    Enzymatic hydrolysis led to improve functional properties and biological activity of protein by-products, which can be further used as protein ingredients for food and feed applications. The effects of proteolytic enzyme modification of egg-yolk protein preparation (YP) and white protein preparation (WP), obtained as the by-products left during the course of lecithin, lysozyme, and cystatin isolation on their biological and functional properties, were evaluated by treating a commercial Neutrase. The antihypertensive and antioxidative properties of YP and WP hydrolysates were evaluated based on their angiotensin-converting enzyme (ACE)-inhibitory activity and radical scavenging (DPPH) capacity, ferric reducing power, and chelating of iron activity. The functionality of obtained hydrolysates was also determined. Neutrase caused a degree of hydrolysis (DH) of YP and WP by-products: 27.6% and 20.9%, respectively. In each of them, mixture of peptides with different molecular masses were also observed. YP hydrolysate showed high levels of antioxidant activity. The scavenging capacity, ferric reducing power, and chelating capacity were observed at the level: 0.44 μmol/L Trolox mg−1, 177.35 μg Fe2+ mg−1, and 549.87 μg Fe2+ mg−1, respectively. YP hydrolysate also exhibited significant ACE-inhibitory activity, in which the level was 59.2 μg. Protein solubility was significantly improved as the DH increased. WP hydrolysate showed high water-holding capacity of 43.2. This study indicated that YP and WP hydrolysates could be used in foods as natural antioxidants and functionality enhancers. PMID:24804027

  3. Dependence of Temporal Diffusion Spectra on Microstructural Properties of Biological Tissues

    PubMed Central

    Xu, Junzhong; Does, Mark D.; Gore, John C.

    2010-01-01

    The apparent diffusion coefficient (ADC) measured using magnetic resonance imaging (MRI) methods provides information on micro-structural properties of biological tissues, and thus has found applications as a useful biomarker for assessing changes such as those that occur in ischemic stroke and cancer. Conventional pulsed gradient spin echo (PGSE) methods are in widespread use and provide information on, for example, variations in cell density. The oscillating gradient spin echo (OGSE) method has the additional ability to probe diffusion behaviors more readily at short diffusion times, and the temporal diffusion spectrum obtained by the OGSE method provides a unique tool for characterizing tissues over different length scales, including structural features of intra-cellular spaces. It has previously been reported that several tissue properties can affect ADC measurements significantly, and the precise biophysical mechanisms that account for ADC changes in different situations are still unclear. Those factors may vary in importance depending on the time and length scale over which measurements are made. In the present work, a comprehensive numerical simulation is used to investigate the dependence of the temporal diffusion spectra measured by OGSE methods on different micro-structural properties of biological tissues, including cell size, cell membrane permeability, intracellular volume fraction, intra-nucleus and intra-cytoplasm diffusion coefficients, nuclear size and T2 relaxation times. Some unique characteristics of the OGSE method at relatively high frequencies are revealed. The results presented in the paper offer a framework for better understanding possible causes of diffusion changes and may be useful to assist the interpretation of diffusion data from OGSE measurements. PMID:21129880

  4. White mineral trioxide aggregate mixed with calcium chloride dihydrate: chemical analysis and biological properties

    PubMed Central

    2017-01-01

    Objectives This study aimed to evaluate the chemical and biological properties of fast-set white mineral trioxide aggregate (FS WMTA), which was WMTA combined with calcium chloride dihydrate (CaCl2·2H2O), compared to that of WMTA. Materials and Methods Surface morphology, elemental, and phase analysis were examined using scanning electron microscope (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD), respectively. The cytotoxicity and cell attachment properties were evaluated on human periodontal ligament fibroblasts (HPLFs) using methyl-thiazol-diphenyltetrazolium (MTT) assay and under SEM after 24 and 72 hours, respectively. Results Results showed that the addition of CaCl2·2H2O to WMTA affected the surface morphology and chemical composition. Although FS WMTA exhibited a non-cytotoxic profile, the cell viability values of this combination were lesser than WMTA, and the difference was significant in 7 out of 10 concentrations at the 2 time intervals (p < 0.05). HPLFs adhered over the surface of WMTA and at the interface, after 24 hours of incubation. After 72 hours, there were increased numbers of HPLFs with prominent cytoplasmic processes. Similar findings were observed with FS WMTA, but the cells were not as confluent as with WMTA. Conclusions The addition of CaCl2·2H2O to WMTA affected its chemical properties. The favorable biological profile of FS WMTA towards HPLFs may have a potential impact on its clinical application for repair of perforation defects. PMID:28808634

  5. Extracellular polysaccharides from Ascomycota and Basidiomycota: production conditions, biochemical characteristics, and biological properties.

    PubMed

    Osińska-Jaroszuk, Monika; Jarosz-Wilkołazka, Anna; Jaroszuk-Ściseł, Jolanta; Szałapata, Katarzyna; Nowak, Artur; Jaszek, Magdalena; Ozimek, Ewa; Majewska, Małgorzata

    2015-12-01

    Fungal polysaccharides (PSs) are the subject of research in many fields of science and industry. Many properties of PSs have already been confirmed and the list of postulated functions continues to grow. Fungal PSs are classified into different groups according to systematic affinity, structure (linear and branched), sugar composition (homo- and heteropolysaccharides), type of bonds between the monomers (β-(1 → 3), β-(1 → 6), and α-(1 → 3)) and their location in the cell (cell wall PSs, exoPSs, and endoPSs). Exopolysaccharides (EPSs) are most frequently studied fungal PSs but their definition, classification, and origin are still not clear and should be explained. Ascomycota and Basidiomycota fungi producing EPS have different ecological positions (saprotrophic and endophytic, pathogenic or symbiotic-mycorrhizae fungi); therefore, EPSs play different biological functions, for example in the protection against environmental stress factors and in interactions with other organisms. EPSs obtained from Ascomycota and Basidiomycota fungal cultures are known for their antioxidant, immunostimulating, antitumor, and antimicrobial properties. The major objective of the presented review article was to provide a detailed description of the state-of-the-art knowledge of the effectiveness of EPS production by filamentous and yeast Ascomycota and Basidiomycota fungi and techniques of derivation of EPSs, their biochemical characteristics, and biological properties allowing comprehensive analysis as well as indication of similarities and differences between these fungal groups. Understanding the role of EPSs in a variety of processes and their application in food or pharmaceutical industries requires improvement of the techniques of their derivation, purification, and characterization. The detailed analyses of data concerning the derivation and application of Ascomycota and Basidiomycota EPSs can facilitate development and trace the direction of application of these EPSs

  6. A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties.

    PubMed

    Mastrogiacomo, S; Güvener, N; Dou, W; Alghamdi, H S; Camargo, W A; Cremers, J G O; Borm, P J A; Heerschap, A; Oosterwijk, E; Jansen, J A; Walboomers, X F

    2017-08-24

    Different materials have been used for vital dental pulp treatment. Preferably a pulp capping agent should show appropriate biological performance, excellent handling properties, and a good imaging contrast. These features can be delivered into a single material through the combination of therapeutic and diagnostic agents (i.e. theranostic). Calcium phosphate based composites (CPCs) are potentially ideal candidate for pulp treatment, although poor imaging contrast and poor dentino-inductive properties are limiting their clinical use. In this study, a theranostic dental pulp capping agent was developed. First, imaging properties of the CPC were improved by using a core-shell structured dual contrast agent (csDCA) consisting of superparamagnetic iron oxide (SPIO) and colloidal gold, as MRI and CT contrast agent respectively. Second, biological properties were implemented by using a dentinogenic factor (i.e. bone morphogenetic protein 2, BMP-2). The obtained CPC/csDCA/BMP-2 composite was tested in vivo, as direct pulp capping agent, in a male Habsi goat incisor model. Our outcomes showed no relevant alteration of the handling and mechanical properties (e.g. setting time, injectability, and compressive strength) by the incorporation of csDCA particles. In vivo results proved MRI contrast enhancement up to 7weeks. Incisors treated with BMP-2 showed improved tertiary dentin deposition as well as faster cement degradation as measured by µCT assessment. In conclusion, the presented theranostic agent matches the imaging and regenerative requirements for pulp capping applications. In this study, we combined diagnostic and therapeutic agents in order to developed a theranostic pulp capping agent with enhanced MRI and CT contrast and improved dentin regeneration ability. In our study we cover all the steps from material preparation, mechanical and in vitro characterization, to in vivo study in a goat dental model. To the best of our knowledge, this is the first time that a

  7. The biological properties of the silver- and copper-doped ceramic biomaterial

    NASA Astrophysics Data System (ADS)

    Lysenko, Oleksandr; Dubok, Oleksii; Borysenko, Anatolii; Shinkaruk, Oleksandr

    2015-04-01

    The biological properties of nanostructured bioactive ceramic composite (BCC) granules doped with 0.1-10 at.% silver and 0.05-5 at.% copper have been investigated both in vitro and in vivo to develop effective alloplastic material for infected bone defect substitute. It is assumed that the granules consisting of biphasic calcium phosphate and bioactive glass ceramics due to their nanoscale (15-40 nm) and multiphase structure, bioelement placement in different ceramic phases as well as antimicrobial effect should improve osteogenic properties and biocompatibility. Tests in vitro have been conducted with multipotent mesenchymal stromal cells (MSCs) and test strains of microorganisms. The same biocomposite has been used in vivo to study the repair of bone defects in animal model. The findings indicate that doped BCC leads to antimicrobial activity. Inhibition of MSCs growth has been observed for granules doped with ions of more than 1 at.% silver and 0.5 at.% copper. The results of the in vivo study reveal that BCC implantation significantly improves bone reparation. Differences between bone repair with undoped and doped, with 1 at.% silver and 0.5 at.% copper, ceramic samples were not observed. The BCC doped within 0.5-1 at.% silver and 0.25-0.5 at.% copper stimulates bone tissue repair and has satisfactory biocompatibility and antimicrobial properties.

  8. Mechanical and biological properties of chitosan/carbon nanotube nanocomposite films

    PubMed Central

    Aryaei, Ashkan; Jayatissa, Ahalapitiya H.; Jayasuriya, Ambalangodage C.

    2015-01-01

    In this paper, different concentrations of multi-walled carbon nanotube (MWCNT) were homogeneously dispersed throughout the chitosan (CS) matrix. A simple solvent-cast method was used to fabricate chitosan films with 0.1, 0.5, and 1% of MWCNT with the average diameter around 30 nm. The CS/MWCNT films were characterized for structural, viscous and mechanical properties with optical microscopy, wide-angle X-ray diffraction, Raman spectroscopy, tensile test machine, and microindentation testing machine. Murine osteoblasts were used to examine the cell viability and attachment of the nanocomposite films at two time points. In comparison to the pure chitosan film, the mechanical properties, including the tensile modulus and strength of the films were greatly improved by increasing the percentage of MWCNT. Furthermore, adding MWCNT up to 1% increased the viscosity of the chitosan solution by 15%. However, adding MWCNT decreased the samples ductility and transparency. In biological point of view, no toxic effect on osteoblasts was observed in the presence of different percentages of MWCNT at day 3 and day 7. This investigation suggested MWCNT could be a promising candidate for improving chitosan mechanical properties without inducing remarkable cytotoxicity on bone cells. PMID:24108584

  9. Possible prebiotic significance of polyamines in the condensation, protection, encapsulation, and biological properties of DNA

    NASA Astrophysics Data System (ADS)

    Baeza, Isabel; Ibáñez, Miguel; Wong, Carlos; Chávez, Pedro; Gariglio, Patricio; Oró, J.

    1992-07-01

    Some properties of DNA condensed with spermidine have been compared with the properties of DNA condensed with Co3+(NH3)6 to determine whether condensation of DNA with these trivalent cations protects DNA against the action of DNase I and increases transcription and encapsulation of DNA into liposomes. It was shown that DNA condensed with Co3+(NH3)6 was resistant to the action of the endonuclease DNase I such as DNA condensed with spermidine was. However, DNA condensed with Co3+(NH3)6 was significantly less active in transcription with theE. coli RNA polymerase than DNA-spermidine condensed forms. In addition, it was demonstrated that both compacted forms of DNA were more efficiently encapsulated into neutral liposomes; however, negatively, charged liposomes were scarcely formed in the presence of DNA condensed with Co3+(NH3)6. These experiments and the well documented properties of polyamines increasing the resistance to radiations and hydrolysis of nucleic acids, as well as their biological activities, such as replication, transcription, and translation, together with the low concentration of Co3+ in the environment, lead us to propose spermidine as a plausible prebiotic DNA condensing agent rather than Co3+ and the basic proteins proposed by other authors. Then, we consider the possible role and relevance of the polyamine-nucleic acids complexes in the evolution of life.

  10. Possible prebiotic significance of polyamines in the condensation, protection, encapsulation, and biological properties of DNA

    NASA Technical Reports Server (NTRS)

    Baeza, I.; Ibanez, M.; Wong, C.; Chavez, P.; Gariglio, P.; Oro, J.

    1991-01-01

    Some properties of DNA condensed with spermidine have been compared with the properties of DNA condensed with Co3+(NH3)6 to determine whether condensation of DNA with these trivalent cations protects DNA against the action of DNase I and increases transcription and encapsulation of DNA into liposomes. It was shown that DNA condensed with Co3+(NH3)6 was resistant to the action of the endonuclease DNase I such as DNA condensed with spermidine was. However, DNA condensed with Co3+(NH3)6 was significantly less active in transcription with the E. coli RNA polymerase than DNA-spermidine condensed forms. In addition, it was demonstrated that both compacted forms of DNA were more efficiently encapsulated into neutral liposomes; however, negatively, charged liposomes were scarcely formed in the presence of DNA condensed with Co3+(NH3)6. These experiments and the well documented properties of polyamines increasing the resistance to radiations and hydrolysis of nucleic acids, as well as their biological activities, such as replication, transcription, and translation, together with the low concentration of Co3+ in the environment, lead us to propose spermidine as a plausible prebiotic DNA condensing agent rather than Co3+ and the basic proteins proposed by other authors. Then, we consider the possible role and relevance of the polyamine-nucleic acids complexes in the evolution of life.

  11. Biological and physical properties of autogenous vascularized fibular grafts in dogs

    SciTech Connect

    Goldberg, V.M.; Stevenson, S.; Shaffer, J.W.; Davy, D.; Klein, L.; Zika, J.; Field, G. )

    1990-07-01

    The biological and biomechanical properties of normal fibulae, fibulae that had had a sham operation, and both vascularized and non-vascularized autogenous grafts were studied in dogs at three months after the operation. The study was designed to quantify and correlate changes in these properties in orthotopic, stably fixed, weight-bearing grafts and to provide a baseline for additional studies of allografts. The grafts were eight centimeters long and internally fixed. The mechanical properties of the grafts were studied by torsional testing. Metabolic turnover of the grafts was evaluated by preoperative labeling of the dogs with 3H-tetracycline for resorption of bone mineral and with 3H-proline for turnover of collagen. Cortical bone area and porosity were measured. Postoperative formation of bone was evaluated by sequential labeling with fluorochrome. The vascularized grafts resembled the fibulae that had had a sham operation and those that had not had an operation with regard to the total number of osteons and the remodeling process, as measured both morphometrically and metabolically. The vascularized grafts were stronger and stiffer than the non-vascularized grafts and were not different from the bones that had had a sham operation. In contrast, the non-vascularized grafts were smaller, weaker, less stiff, and more porotic, had fewer osteons, and demonstrated increased turnover and resorption compared with the vascularized grafts, the bones that had had a sham operation, and the bones that had not been operated on.

  12. Insights on the Optical Properties of Estuarine DOM – Hydrological and Biological Influences

    PubMed Central

    Santos, Luísa; Pinto, António; Filipe, Olga; Cunha, Ângela; Santos, Eduarda B. H.

    2016-01-01

    Dissolved organic matter (DOM) in estuaries derives from a diverse array of both allochthonous and autochthonous sources. In the estuarine system Ria de Aveiro (Portugal), the seasonality and the sources of the fraction of DOM that absorbs light (CDOM) were inferred using its optical and fluorescence properties. CDOM parameters known to be affected by aromaticity and molecular weight were correlated with physical, chemical and meteorological parameters. Two sites, representative of the marine and brackish water zones of the estuary, and with different hydrological characteristics, were regularly surveyed along two years, in order to determine the major influences on CDOM properties. Terrestrial-derived compounds are the predominant source of CDOM in the estuary during almost all the year and the two estuarine zones presented distinct amounts, as well as absorbance and fluorescence characteristics. Freshwater inputs have major influence on the dynamics of CDOM in the estuary, in particular at the brackish water zone, where accounted for approximately 60% of CDOM variability. With a lower magnitude, the biological productivity also impacted the optical properties of CDOM, explaining about 15% of its variability. Therefore, climate changes related to seasonal and inter-annual variations of the precipitation amounts might impact the dynamics of CDOM significantly, influencing its photochemistry and the microbiological activities in estuarine systems. PMID:27195702

  13. Possible prebiotic significance of polyamines in the condensation, protection, encapsulation, and biological properties of DNA

    NASA Technical Reports Server (NTRS)

    Baeza, I.; Ibanez, M.; Wong, C.; Chavez, P.; Gariglio, P.; Oro, J.

    1991-01-01

    Some properties of DNA condensed with spermidine have been compared with the properties of DNA condensed with Co3+(NH3)6 to determine whether condensation of DNA with these trivalent cations protects DNA against the action of DNase I and increases transcription and encapsulation of DNA into liposomes. It was shown that DNA condensed with Co3+(NH3)6 was resistant to the action of the endonuclease DNase I such as DNA condensed with spermidine was. However, DNA condensed with Co3+(NH3)6 was significantly less active in transcription with the E. coli RNA polymerase than DNA-spermidine condensed forms. In addition, it was demonstrated that both compacted forms of DNA were more efficiently encapsulated into neutral liposomes; however, negatively, charged liposomes were scarcely formed in the presence of DNA condensed with Co3+(NH3)6. These experiments and the well documented properties of polyamines increasing the resistance to radiations and hydrolysis of nucleic acids, as well as their biological activities, such as replication, transcription, and translation, together with the low concentration of Co3+ in the environment, lead us to propose spermidine as a plausible prebiotic DNA condensing agent rather than Co3+ and the basic proteins proposed by other authors. Then, we consider the possible role and relevance of the polyamine-nucleic acids complexes in the evolution of life.

  14. Effect of Gamma Irradiation on Structural and Biological Properties of a PLGA-PEG-Hydroxyapatite Composite

    PubMed Central

    Shahabi, Sima; Najafi, Farhood; Majdabadi, Abbas; Hooshmand, Tabassom; Haghbin Nazarpak, Masoumeh; Karimi, Batool

    2014-01-01

    Gamma irradiation is able to affect various structural and biological properties of biomaterials In this study, a composite of Hap/PLGA-PEG and their ingredients were submitted to gamma irradiation doses of 25 and 50 KGy. Various properties such as molecular weight (GPC), thermal behavior (DSC), wettability (contact angle), cell viability (MTT assay), and alkaline phosphatase activity were studied for the composites and each of their ingredients. The results showed a decrease in molecular weight of copolymer with no change in the glass transition and melting temperatures after gamma irradiation. In general gamma irradiation can increase the activation energy ΔH of the composites and their ingredients. While gamma irradiation had no effect on the wettability of copolymer samples, there was a significant decrease in contact angle of hydroxyapatite and composites with increase in gamma irradiation dose. This study showed an increase in biocompatibility of hydroxyapatite with gamma irradiation with no significant effect on cell viability in copolymer and composite samples. In spite of the fact that no change occurred in alkaline phosphatase activity of composite samples, results indicated a decrease in alkaline phosphatase activity in irradiated hydroxyapatites. These effects on the properties of PLGA-PEG-hydroxyapatite can enhance the composite application as a biomaterial. PMID:25574485

  15. Engineering the mechanical and biological properties of nanofibrous vascular grafts for in situ vascular tissue engineering.

    PubMed

    Henry, Jeffrey J D; Yu, Jian; Wang, Aijun; Lee, Randall; Fang, Jun; Li, Song

    2017-08-17

    Synthetic small diameter vascular grafts have a high failure rate, and endothelialization is critical for preventing thrombosis and graft occlusion. A promising approach is in situ tissue engineering, whereby an acellular scaffold is implanted and provides stimulatory cues to guide the in situ remodeling into a functional blood vessel. An ideal scaffold should have sufficient binding sites for biomolecule immobilization and a mechanical property similar to native tissue. Here we developed a novel method to blend low molecular weight (LMW) elastic polymer during electrospinning process to increase conjugation sites and to improve the mechanical property of vascular grafts. LMW elastic polymer improved the elasticity of the scaffolds, and significantly increased the amount of heparin conjugated to the micro/nanofibrous scaffolds, which in turn increased the loading capacity of vascular endothelial growth factor (VEGF) and prolonged the release of VEGF. Vascular grafts were implanted into the carotid artery of rats to evaluate the in vivo performance. VEGF treatment significantly enhanced endothelium formation and the overall patency of vascular grafts. Heparin coating also increased cell infiltration into the electrospun grafts, thus increasing the production of collagen and elastin within the graft wall. This work demonstrates that LMW elastic polymer blending is an approach to engineer the mechanical and biological property of micro/nanofibrous vascular grafts for in situ vascular tissue engineering.

  16. Influence of Oil Contamination on Physical and Biological Properties of Forest Soil After Chainsaw Use.

    PubMed

    Klamerus-Iwan, Anna; Błońska, Ewa; Lasota, Jarosław; Kalandyk, Agnieszka; Waligórski, Piotr

    Forestry works using chainsaws result in up to 7 million liters of various mineral oils being soaked annually into forest soils. These substances, containing a complex mixture of polycyclic aromatic hydrocarbons (PAHs), are highly toxic. The aim of the study was to determine the effect of oil contamination with PAHs on the physical and biological properties of forest soils. The study area was located in southern Poland in the Miechów forest district. The experiment was conducted on four treatment blocks with various amounts of oil addition. The study included the determination of PAH content, dehydrogenase and urease activity, and biomass of earthworms. Physical properties were determined using the dryer method and Kopecky rings of 250 cm(3) volume. The results obtained confirmed the hypothesis that oil contamination with PAHs modified the physical properties of forest soils and oil had a negative impact on enzyme activity in soil. Enzyme activity in the studied soils was negatively correlated with PAH content. Earthworm population density reflected the contamination level of oil-contaminated soils.

  17. Mechanical and biological properties of chitosan/carbon nanotube nanocomposite films.

    PubMed

    Aryaei, Ashkan; Jayatissa, Ahalapitiya H; Jayasuriya, Ambalangodage C

    2014-08-01

    In this article, different concentrations of multiwalled carbon nanotube (MWCNT) were homogeneously dispersed throughout the chitosan (CS) matrix. A simple solvent-cast method was used to fabricate chitosan films with 0.1, 0.5, and 1% of MWCNT with the average diameter around 30 nm. The CS/MWCNT films were characterized for structural, viscous and mechanical properties with optical microscopy, wide-angle X-ray diffraction, Raman spectroscopy, tensile test machine, and microindentation testing machine. Murine osteoblasts were used to examine the cell viability and attachment of the nanocomposite films at two time points. In comparison to the pure chitosan film, the mechanical properties, including the tensile modulus and strength of the films, were greatly improved by increasing the percentage of MWCNT. Furthermore, adding MWCNT up to 1% increased the viscosity of the chitosan solution by 15%. However, adding MWCNT decreased the samples ductility and transparency. In biological point of view, no toxic effect on osteoblasts was observed in the presence of different percentages of MWCNT at day 3 and day 7. This investigation suggested MWCNT could be a promising candidate for improving chitosan mechanical properties without inducing remarkable cytotoxicity on bone cells.

  18. Seasonal variations of phenolic compounds and biological properties in sage (Salvia officinalis L.).

    PubMed

    Generalić, Ivana; Skroza, Danijela; Surjak, Jana; Možina, Sonja Smole; Ljubenkov, Ivica; Katalinić, Ana; Simat, Vida; Katalinić, Višnja

    2012-02-01

    The aim was to investigate the phenolic content, antioxidant capacity, and antibacterial activity of Dalmatian sage (Salvia officinalis L.) leaves collected during different vegetation periods. Separation and quantification of the individual phenols were performed by reversed-phase (RP)-HPLC coupled with a PDA (photodiode array) detector and using an internal standard, while the contents of total phenols, flavonoids, flavones, and flavonols were determined spectrophotometrically. The antioxidant properties of the sage leaf extracts were evaluated using five different antioxidant assays (FRAP, DPPH, ABTS, Briggs-Rauscher reaction, and β-carotene bleaching). The antimicrobial activity of the extracts was tested against two Gram-positive (Bacillus cereus and Staphylococcus aureus) and two Gram-negative (Salmonella Infantis and Escherichia coli) bacterial reference strains. All extracts were extremely rich in phenolic compounds, and provided good antioxidant and antibacterial properties, but the phenophase in which the leaves were collected affected the phenolic composition of the sage extracts and consequently their biological activity. The May Extract, the richest in total flavonoids, showed the best antioxidant properties and the highest antimicrobial activity. Thus, collection of the plants during May seems the best choice for further use of them in the pharmaceutical and food industry.

  19. Gold nanoparticles stabilized by cationic carbosilane dendrons: synthesis and biological properties.

    PubMed

    Peña-González, Cornelia E; Pedziwiatr-Werbicka, Elzbieta; Shcharbin, Dzmitry; Guerrero-Beltrán, Carlos; Abashkin, Viktar; Loznikova, Svetlana; Jiménez, José L; Muñoz-Fernández, M Ángeles; Bryszewska, Maria; Gómez, Rafael; Sánchez-Nieves, Javier; de la Mata, F Javier

    2017-01-16

    Gold nanoparticles (AuNPs) and polycationic macromolecules are used as gene carriers. Their behaviour is dependent on several factors, such as the size and type of the framework, charge, etc. We have combined both types of systems and prepared AuNPs covered with cationic carbosilane dendrons with the aim to evaluate their biocompatibility. Water soluble dendronized cationic AuNPs were prepared following a straightforward procedure from dendrons, a gold precursor and a reducing agent in water and were characterized by (1)H NMR, transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), ultraviolet spectroscopy (UV), and zeta potential (ZP). The biological properties of dendrons and AuNPs were determined by hemolysis, platelet aggregation and lymphocyte proliferation. These assays reflect modification of dendron properties when covering nanoparticles. For dendrons, hemolysis and platelet aggregation are generation dependent whilst, for AuNPs these properties are related to the bigger size of NPs. On the other hand, none of the systems induced lymphocyte proliferation. Selected cationic dendrons and AuNPs were chosen for gene delivery experiments employing a small interference RNA (siRNA Nef) against human immunodeficiency virus (HIV).

  20. Fluorescence properties of aurone derivatives: an experimental and theoretical study with some preliminary biological applications.

    PubMed

    Espinosa-Bustos, Christian; Cortés-Arriagada, Diego; Soto-Arriaza, Marco A; Robinson-Duggon, José; Pizarro, Nancy; Cabrera, Alan R; Fuentealba, Denis; Salas, Cristian O

    2017-08-09

    In this paper, we explored the fluorescence properties of eight aurone derivatives bearing methoxy groups and bromine atoms as substituents in the benzene rings. All derivatives showed strong solvatochromic absorption and emission properties in solvents of different polarities. Some of them showed high fluorescence quantum yields, which make them potential compounds for sensing applications. The position of the methoxy groups in the benzofuranone moiety and the presence of bromine atoms in the benzene ring had a strong influence on the fluorescence behaviour of the aurones. DFT calculations allowed us to explain the emission properties of aurones and their solvatochromism, which was related to an excited state with strong charge-transfer character. Aurone 4 has the most promising characteristics showing a large difference in the quantum yields and large Stokes shifts depending on the solvent polarities. These results prompted us to explore some preliminary biological applications for aurone 4 such as the sensing of hydrophobic pockets of a protein and its thermotropic behaviour in liposomes.

  1. [Modeling and experimental study on frequency-domain electricity properties of biological materials].

    PubMed

    Tian, Hua; Luo, Shiqiang; Zhang, Rui; Yang, Gang; Huang, Hua

    2009-12-01

    Frequency-domain electricity properties of four objects, including bullfrog skin, bullfrog muscle, triply distilled water and 0.9% NaCl, were tested in the range of 100Hz-10MHz using home-made electrode and measuring system. The experimental results showed that the resistance of 0.9% NaCl decreased dramatically, that the amplitude frequency characteristics of bullfrog's muscle and skin were similar, but that of triply distilled water did not change significantly. The frequency dependence of 0.9% NaCl showed that the electrode had great influence on the measuring system, so a new equivalent circuit model based on the electrode system was needed. These findings suggest that the new five-parameter equivalent circuit model, which embodies considerations on the interaction between electrodes and tissues, is a reasonable equivalent circuit for studying the electrical characteristics of biological materials.

  2. Actinobacteria mediated synthesis of nanoparticles and their biological properties: A review.

    PubMed

    Manivasagan, Panchanathan; Venkatesan, Jayachandran; Sivakumar, Kannan; Kim, Se-Kwon

    2016-01-01

    Nanotechnology is gaining tremendous attention in the present century due to its expected impact on many important areas such as medicine, energy, electronics, and space industries. In this context, actinobacterial biosynthesis of nanoparticles is a reliable, eco-friendly, and important aspect of green chemistry approach that interconnects microbial biotechnology and nanobiotechnology. Antibiotics produced by actinobacteria are popular in almost all the therapeutic measures and it is known that these microbes are also helpful in the biosynthesis of nanoparticles with good surface and size characteristics. In fact, actinobacteria are efficient producers of nanoparticles that show a range of biological properties, namely, antibacterial, antifungal, anticancer, anti-biofouling, anti-malarial, anti-parasitic, antioxidant, etc. This review describes the potential use of the actinobacteria as the novel sources for the biosynthesis of nanoparticles with improved biomedical applications.

  3. A mini-review of chemical and biological properties of polysaccharides from Momordica charantia.

    PubMed

    Zhang, Fan; Lin, Lihua; Xie, Jianhua

    2016-11-01

    Recently, isolation and characterization of bioactive polysaccharides from natural resources have attracted increasing interest. Momordica charantia L. (M. charantia), belongs to the Curcubitaceae family, which is widely distributed in the tropical and subtropical regions of the world, and has been used as herbal medicine and a vegetable for thousands of years. M. charantia polysaccharides, as major active ingredients of M. charantia, have attracted a great deal of attention because of their various biological activities, such as antitumor, immunomodulation, antioxidant, anti-diabetes, radioprotection, and hepatoprotection. The present review provides the most complete summary of the research progress on the polysaccharides isolated from M. charantia, including the extraction, separation, physical-chemical properties, structural characteristics, and bioactivities during the last ten years. This review also provides a foundation for the further development and application in the field of M. charantia polysaccharides.

  4. Biological and molecular properties of yellow venom of the Amazonian coral snake Micrurus surinamensis.

    PubMed

    Oliveira, Fabiana da Rocha; Noronha, Maria das Dores Nogueira; Lozano, Jorge Luis Lopez

    2017-01-01

    The coral snake Micrurus surinamensis, which is widely distributed throughout Amazonia, has a neurotoxic venom. It is important to characterize the biological and molecular properties of this venom in order to develop effective antitoxins. Toxins from the venom of M. surinamensis were analyzed by two-dimensional polyacrylamide gel electrophoresis and their neurotoxic effects in vivo were evaluated. Most proteins in the venom had masses < 14kDa, low phospholipase A2 activity, and no proteolytic activity. The toxins inhibited the coagulation cascade. The venom had neurotoxic effects in mice, with a median lethal dose upon intravenous administration of 700 µg/kg. Immunogenic studies revealed abundant cross-reactivity of antielapidic serum with 14kDa toxins and limited cross-reactivity with toxins < 10kDa. These results indicate that antielapidic serum against M. surinamensis venom has weak potency (0.35mg/ml) in mice.

  5. Review of the biological properties and toxicity of bee propolis (propolis).

    PubMed

    Burdock, G A

    1998-04-01

    Propolis is a multifunctional material used by bees in the construction and maintenance of their hives. Use of propolis by humans has a long history, predated only by the discovery of honey. Use of products containing propolis have resulted in extensive dermal contact and it is now increasingly being used a dietary supplement. Unlike many 'natural' remedies, there is a substantive database on the biological activity and toxicity of propolis indicating it may have many antibiotic, antifungal, antiviral and antitumour properties, among other attributes. Although reports of allergic reactions are not uncommon, propolis is relatively non-toxic, with a no-effect level (NOEL) in a 90-mouse study of 1400 mg/kg body weight/day.

  6. Understanding Oxadiazolothiazinone Biological Properties: Negative Inotropic Activity versus Cytochrome P450-Mediated Metabolism.

    PubMed

    Carosati, Emanuele; Cosimelli, Barbara; Ioan, Pierfranco; Severi, Elda; Katneni, Kasiram; Chiu, Francis C K; Saponara, Simona; Fusi, Fabio; Frosini, Maria; Matucci, Rosanna; Micucci, Matteo; Chiarini, Alberto; Spinelli, Domenico; Budriesi, Roberta

    2016-04-14

    We present a series of oxadiazolothiazinones, selective inotropic agents on isolated cardiac tissues, devoid of chronotropy and vasorelaxant activity. Functional and binding data for the precursor of the series (compound 1) let us hypothesize LTCC blocking activity and the existence of a recognition site specific for this scaffold. We synthesized and tested 22 new derivatives: introducing a para-methoxyphenyl at C-8 led to compound 12 (EC50 = 0.022 μM), twice as potent as its para-bromo analogue (1). For 10 analogues, we extended the characterization of the biological properties by including the assessment of metabolic stability in human liver microsomes and cytochrome P450 inhibition potential. We observed that the methoxy group led to active compounds with low metabolic stability and high CYP inhibition, whereas the protective effect of bromine resulted in enhanced metabolic stability and reduced CYP inhibition. Thus, we identified two para-bromo benzothiazino-analogues as candidates for further studies.

  7. Spectral, electrical conductivity and biological activity properties of some new azopyrimidine derivatives and their complexes.

    PubMed

    Masoud, Mamdouh S; Khalil, Ekram A; Ramadan, Ahmed M; Gohar, Yousry M; Sweyllam, Amr

    2007-07-01

    The electronic absorption spectra of 5-(o-substituted phenylazo)-6-amino-2-thiouracils and 6-(o-substituted phenylazo)-5-aminouracils containing different substituents are studied at different pH's. The dissociation constants are evaluated and discussed. Phenomenon of tautomerism is more supported by (1)H NMR and (13)C NMR spectra. The electrical conductivity of some ligands and their Co(II), Ni(II) and Cu(II) complexes in the temperature range 293-150K favoured their semiconducting properties where the metal ion forms a bridge to facilitate the flow of the current. The biological activity of some ligands and their complexes are tested against a number of Gram-positive and Gram-negative bacteria. The results showed that some of the compounds have a well considerable activity against some of the organisms.

  8. Ultrastable gold substrates: Properties of a support for high-resolution electron cryomicroscopy of biological specimens

    PubMed Central

    Russo, Christopher J.; Passmore, Lori A.

    2016-01-01

    Electron cryomicroscopy (cryo-EM) allows structure determination of a wide range of biological molecules and specimens. All-gold supports improve cryo-EM images by reducing radiation-induced motion and image blurring. Here we compare the mechanical and electrical properties of all-gold supports to amorphous carbon foils. Gold supports are more conductive, and have suspended foils that are not compressed by differential contraction when cooled to liquid nitrogen temperatures. These measurements show how the choice of support material and geometry can reduce specimen movement by more than an order of magnitude during low-dose imaging. We provide methods for fabrication of all-gold supports and preparation of vitrified specimens. We also analyse illumination geometry for optimal collection of high resolution, low-dose data. Together, the support structures and methods herein can improve the resolution and quality of images from any electron cryomicroscope. PMID:26592474

  9. Ultrastable gold substrates: Properties of a support for high-resolution electron cryomicroscopy of biological specimens.

    PubMed

    Russo, Christopher J; Passmore, Lori A

    2016-01-01

    Electron cryomicroscopy (cryo-EM) allows structure determination of a wide range of biological molecules and specimens. All-gold supports improve cryo-EM images by reducing radiation-induced motion and image blurring. Here we compare the mechanical and electrical properties of all-gold supports to amorphous carbon foils. Gold supports are more conductive, and have suspended foils that are not compressed by differential contraction when cooled to liquid nitrogen temperatures. These measurements show how the choice of support material and geometry can reduce specimen movement by more than an order of magnitude during low-dose imaging. We provide methods for fabrication of all-gold supports and preparation of vitrified specimens. We also analyse illumination geometry for optimal collection of high resolution, low-dose data. Together, the support structures and methods herein can improve the resolution and quality of images from any electron cryomicroscope. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Green tea catechins: biologic properties, proposed mechanisms of action, and clinical implications.

    PubMed

    Rosen, Ted

    2012-11-01

    Botanical products, including and especially green tea leaves, have a wide range of both reputed and demonstrated health benefits and have been used medicinally for thousands of years. This paper focuses on green tea catechins, principally reviewing their known biologic properties and potential mechanisms of action (MOAs). The primary objective is to discuss the proposed antiviral, antiproliferative, and immunostimulatory activity of catechins based on strong evidence from in vitro and in vivo studies conducted to date, including two preclinical in vitro studies with sinecatechins, a proprietary mixture of catechins. This review also discusses the clinical implications of catechins for the treatment of external genital and perianal warts (EGWs) and other conditions caused by human papillomavirus (HPV). While the MOA of catechins in the treatment of EGWs and other HPV-related conditions may be related to or associated with postulated or proven antiviral and immunostimulatory activity, the precise clinical significance of the various in vitro findings remains largely unknown.

  11. Fluorescent-magnetic hybrid nanostructures: preparation, properties, and applications in biology.

    PubMed

    Quarta, Alessandra; Di Corato, Riccardo; Manna, Liberato; Ragusa, Andrea; Pellegrino, Teresa

    2007-12-01

    Research on nanocomposite materials aims at developing nanoscale composites with innovative optical, chemical, and magnetic properties, all combined in one single nanostructure. In this scenario, nanostructures which show simultaneously fluorescent and magnetic features are of particular interest for pharmaceutical and biomedical applications. In this review, we will focus our attention on magnetic-fluorescent nanocomposite based on colloidal iron oxide nanocrystals combined with different classes of fluorophores which can be either organic dyes, such as fluoresceins, cyanines, porphyrins, or colloidal quantum dots. We will give an overview of the preparation methods of the magnetic-fluorescent nanocomposites that are now available and we will outline the most significant in vitro studies of such nanocomposites on living cells. Some examples of their applications in biology and medicine will also be discussed.

  12. The Influence of Nitrogen on the Biological Properties of Soil Contaminated with Zinc.

    PubMed

    Strachel, Rafał; Wyszkowska, Jadwiga; Baćmaga, Małgorzata

    2017-03-01

    This study analyzed the relationship between nitrogen fertilization and the biological properties of soil contaminated with zinc. The influence of various concentrations of zinc and nitrogen on the microbiological and biochemical activity of soil was investigated. In a laboratory experiment, loamy sand with pHKCl 5.6 was contaminated with zinc (ZnCl2) and fertilized with urea as a source of nitrogen. The activity of acid phosphatase, alkaline phosphatase, urease and β-glucosidase, and microbial counts were determined in soil samples after 2 and 20 weeks of incubation. Zinc generally stimulated hydrolase activity, but the highest zinc dose (1250 mg kg(-1)) led to the inhibition of hydrolases. Nitrogen was not highly effective in neutralizing zinc's negative effect on enzyme activity, but it stimulated the growth of soil-dwelling microorganisms. The changes in soil acidity observed after the addition of urea modified the structure of microbial communities.

  13. Bio-heat transfer model of electroconvulsive therapy: Effect of biological properties on induced temperature variation.

    PubMed

    de Oliveira, Marilia M; Wen, Paul; Ahfock, Tony

    2016-08-01

    A realistic human head model consisting of six tissue layers was modelled to investigate the behavior of temperature profile and magnitude when applying electroconvulsive therapy stimulation and different biological properties. The thermo-electrical model was constructed with the use of bio-heat transfer equation and Laplace equation. Three different electrode montages were analyzed as well as the influence of blood perfusion, metabolic heat and electric and thermal conductivity in the scalp. Also, the effect of including the fat layer was investigated. The results showed that temperature increase is inversely proportional to electrical and thermal conductivity increase. Furthermore, the inclusion of blood perfusion slightly drops the peak temperature. Finally, the inclusion of fat is highly recommended in order to acquire more realistic results from the thermo-electrical models.

  14. Investigation of physical and biological properties of polypyrrole nanotubes-chitosan nanocomposites.

    PubMed

    Upadhyay, J; Kumar, A; Gupta, K; Mandal, M

    2015-11-05

    Polypyrrole nanotubes-chitosan (PPy-NTs:chitosan) nanocomposite films have been synthesized with varying concentration of polypyrrole nanotubes (PPy-NTs) and their physical and biological properties have been investigated. Scanning electron microscopy (SEM) micrographs exhibit the increase in surface roughness of the nanocomposite films with increasing concentration of PPy-NTs. Enhancement in hydrophilicity of the nanocomposite films has been observed after surface functionalization with glutaraldehyde which is attributed to increase in surface energy due to the incorporation of polar groups on the films surface. The increasing amount of PPy-NTs in the nanocomposite leads to an increase in haemolysis activity, while the treatment with glutaraldehyde results in the decrease in haemolysis activity giving rise to higher biocompatibility. Urease immobilization in glutaraldehyde treated films exhibits higher enzymatic activity as compared to that of the untreated films, which is attributed to the enhancement in hydrophilicity and biocompatibility of the PPy-NTs:chitosan nanocomposites after functionalization with glutaraldehyde.

  15. [The biological properties of the HIV isolated from a virus carrier living in the Byelorussian SSR].

    PubMed

    Rytik, P G; van der Groen, G; Eremin, V F; Kolomiets, N D; Popov, S A; Nijs, P; Willems, V; Verkauteren, G; Il'kevich, Iu G; Lemeshko, N N

    1990-01-01

    Biological properties of an AIDS agent first isolated from a native citizen in the USSR are presented. The source of the virus was a young Byelorussian woman who in the near past had had sexual contacts with a citizen from one of the Central Africa countries. The isolate is thought to be of HIV-I type. It replicated perfectly in many continuous lymphocyte lines and had HIV-characteristic morphology. The protein spectrum of the isolate was gp120, gp41, p65/51, p55, p32, p24, p17. Reverse transcriptase activity was detected in the culture fluid of the virus-containing cell cultures. The isolate was designated HIV-IZ.

  16. A comparison of biochemical and biological properties of standard and defective lymphocytic choriomeningitis virus

    PubMed Central

    Welsh, R. M.; Burner, P. A.; Holland, J. J.; Oldstone, M. B. A.; Thompson, H. A.; Villarreal, L. P.

    1975-01-01

    Lymphocytic choriomeningitis (LCM) virus infection of the mouse is the best-studied model of persistent viral infection. In cell culture, persistent LCM virus infections are associated with the production of large quantities of defective interfering (DI) LCM virus. These defective interfering particles cannot replicate by themselves yet can interfere with the replication of the standard virus and prevent the cytolytic effect caused by the standard virus. It is important to determine the mechanism of interference and to establish whether the DI virus plays a role in vivo. Biological and biochemical properties of the standard and DI virus particles and also virus enzymes are compared. Antigenic analyses reveal that cells releasing only DI virus particles have less cell surface expression of viral antigens than cells releasing the standard virus. In the animal model, the DI virus is shown to have a protective effect against the pathogenesis of the LCM virus disease both in the mouse and in the rat. PMID:60182

  17. A comparison of biochemical and biological properties of standard and defective lymphocytic choriomeningitis virus.

    PubMed

    Welsh, R M; Burner, P A; Holland, J J; Oldstone, M B; Thompson, H A; Villarreal, L P

    1975-01-01

    Lymphocytic choriomeningitis (LCM) virus infection of the mouse is the best-studied model of persistent viral infection. In cell culture, persistent LCM virus infections are associated with the production of large quantities of defective interfering (DI) LCM virus. These defective interfering particles cannot replicate by themselves yet can interfere with the replication of the standard virus and prevent the cytolytic effect caused by the standard virus. It is important to determine the mechanism of interference and to establish whether the DI virus plays a role in vivo. Biological and biochemical properties of the standard and DI virus particles and also virus enzymes are compared. Antigenic analyses reveal that cells releasing only DI virus particles have less cell surface expression of viral antigens than cells releasing the standard virus. In the animal model, the DI virus is shown to have a protective effect against the pathogenesis of the LCM virus disease both in the mouse and in the rat.

  18. Unraveling the nanoscale surface properties of chitin synthase mutants of Aspergillus fumigatus and their biological implications.

    PubMed

    Alsteens, David; Aimanianda, Vishukumar; Hegde, Pushpa; Pire, Stéphane; Beau, Rémi; Bayry, Jagadeesh; Latgé, Jean-Paul; Dufrêne, Yves F

    2013-07-16

    Understanding the surface properties of the human opportunistic pathogen Aspergillus fumigatus conidia is essential given the important role they play during the fungal interactions with the human host. Although chitin synthases with myosin motor-like domain (CSM) play a major role in cell wall biosynthesis, the extent to which deletion of the CSM genes alter the surface structural and biophysical-biological properties of conidia is not fully characterized. We used three complementary atomic force microscopy techniques-i.e., structural imaging, chemical force microscopy with hydrophobic tips, and single-molecule force spectroscopy with lectin tips-to gain detailed insights into the nanoscale surface properties (ultrastructure, hydrophobicity) and polysaccharide composition of the wild-type and the chitin synthase mutant (ΔcsmA, ΔcsmB, and ΔcsmA/csmB) conidia of A. fumigatus. Wild-type conidia were covered with a highly hydrophobic layer of rodlet nanostructures. By contrast, the surface of the ΔcsmA mutant was almost completely devoid of rodlets, leading to loss of hydrophobicity and exposure of mannan and chitin polysaccharides. The ΔcsmB and ΔcsmA/csmB mutants showed a different behavior, i.e., the surfaces featured poorly organized rodlet layers, yet with a low hydrophobicity and substantial amounts of exposed mannan and chitin at the surface. As the rodlet layer is important for masking recognition of immunogenic fungal cell wall components by innate immune cells, disappearance of rodlet layers in all three chitin synthase mutant conidia was associated with an activation of human dendritic cells. These nanoscale analyses emphasize the important and distinct roles that the CSMA and CSMB genes play in modulating the surface properties and immune interactions of A. fumigatus and demonstrate the power of atomic force microscopy in fungal genetic studies for assessing the phenotypic characteristics of mutants altered in cell surface organization. Copyright

  19. Biological properties of carbon powders synthesized using chemical vapour deposition and detonation methods.

    PubMed

    Batory, M; Batory, D; Grabarczyk, J; Kaczorowski, W; Kupcewicz, B; Mitura, K; Nasti, T H; Yusuf, N; Niedzielski, P

    2012-12-01

    Carbon powders can be synthesized using variety of CVD and detonation methods. Several interesting properties of carbon powder particles make them a very attractive material examined in many laboratories all over the world. However there is a lack of information discussing investigation of carbon powders directed to its application in pharmaceutical-cosmetic industry and medicine. Earlier investigation results proved that diamond powders present properties fighting free radicals. Presented work discusses the influence of carbon powder particles manufactured using MW/RF PACVD, RF PACVD and detonation methods onto hydro-lipid skin coat. Before the biological examinations physicochemical properties of carbon powders were determined. Grain size, shape and chemical composition of carbon powders were determined using the scanning electron microscopy. Surface functional groups were characterized by IR Fourier-transform spectroscopy and X-ray photoelectron spectroscopy. Structure and phase composition were investigated by means of the Raman spectroscopy. Results of allergy tests performed on laboratory mice proved that carbon powder particles synthesized using different methods do not cause allergy. In the following stage, the group of 20 patients applied the formula including carbon powder on their face skin. The influence of carbon powder onto hydro-lipid skin coat was determined by measurement of such parameters as: pH reaction, skin temperature, lipid fotometry and level of hydration. Additionally, macro pictures of places where the cream had been applied were registered. As the result of the investigation it was found that powders synthesized using various methods present different physicochemical properties which may individually affect the face skin parameters. The noticeable improvement of hydro-lipid skin coat kilter was observed.

  20. Self-Organisation, Thermotropic and Lyotropic Properties of Glycolipids Related to their Biological Implications

    PubMed Central

    Garidel, Patrick; Kaconis, Yani; Heinbockel, Lena; Wulf, Matthias; Gerber, Sven; Munk, Ariane; Vill, Volkmar; Brandenburg, Klaus

    2015-01-01

    Glycolipids are amphiphilic molecules which bear an oligo- or polysaccharide as hydrophilic head group and hydrocarbon chains in varying numbers and lengths as hydrophobic part. They play an important role in life science as well as in material science. Their biological and physiological functions are quite diverse, ranging from mediators of cell-cell recognition processes, constituents of membrane domains or as membrane-forming units. Glycolipids form an exceptional class of liquid-crystal mesophases due to the fact that their self-organisation obeys more complex rules as compared to classical monophilic liquid-crystals. Like other amphiphiles, the supra-molecular structures formed by glycolipids are driven by their chemical structure; however, the details of this process are still hardly understood. Based on the synthesis of specific glycolipids with a clearly defined chemical structure, e.g., type and length of the sugar head group, acyl chain linkage, substitution pattern, hydrocarbon chain lengths and saturation, combined with a profound physico-chemical characterisation of the formed mesophases, the principles of the organisation in different aggregate structures of the glycolipids can be obtained. The importance of the observed and formed phases and their properties are discussed with respect to their biological and physiological relevance. The presented data describe briefly the strategies used for the synthesis of the used glycolipids. The main focus, however, lies on the thermotropic as well as lyotropic characterisation of the self-organised structures and formed phases based on physico-chemical and biophysical methods linked to their potential biological implications and relevance. PMID:26464591

  1. Medicinal properties of mangiferin, structural features, derivative synthesis, pharmacokinetics and biological activities.

    PubMed

    Benard, Outhiriaradjou; Chi, Yuling

    2015-01-01

    The identification of biologically active and potentially therapeutically useful pharmacophores from natural products has been a long-term focus in the pharmaceutical industry. The recent emergence of a worldwide obesity and Type II diabetes epidemic has increased focus upon small molecules that can modulate energy metabolism, insulin sensitivity and fat biology. Interesting preliminary work done on mangiferin (MGF), the predominant constituent of extracts of the mango plant Mangifera indica L., portends potential for this pharmacophore as a novel parent compound for treating metabolic disorders. MGF is comprised of a C-glucosylated xanthone. Owing to the xanthone chemical structure, MGF has a redox active aromatic system and has antioxidant properties. MGF exerts varied and impressive metabolic effects in animals, improving metabolic disorders. For example we have discovered that MGF is a novel activator of the mammalian pyruvate dehydrogenase complex, leading to enhancement of carbohydrate utilization in oxidative metabolism, and leading to increased insulin sensitivity in animal models of obesity and insulin resistance. In addition, recent unbiased proteomics studies revealed that MGF upregulates proteins pivotal for mitochondrial bioenergetics and downregulates proteins controlling de novo lipogenesis in liver, helping to explain protective effects of MGF in prevention of liver steatosis. Several chemical studies have achieved synthesis of MGF, suggesting possible synthetic strategies to alter its chemical structure for development of structure-activity relationship (SAR) information. Ultimately, chemical derivatization studies could lead to the eventual development of novel therapeutics based upon the parent pharmacophore structure. Here we provide comprehensive review on chemical features of MGF, synthesis of its derivatives, its pharmacokinetics and biological activities.

  2. Ultra-weak photon emission from biological samples: definition, mechanisms, properties, detection and applications.

    PubMed

    Cifra, Michal; Pospíšil, Pavel

    2014-10-05

    This review attempts to summarize molecular mechanisms, spectral and intensity properties, detection techniques and applications of ultra-weak photon emission. Ultra-weak photon emission is the chemiluminescence from biological systems where electronically excited species are formed during oxidative metabolic or oxidative stress processes. It is generally accepted that photons are emitted (1) at near UVA, visible, and near IR spectral ranges from 350 to 1300nm and (2) at the intensity of photon emission in the range of several units to several hundreds (oxidative metabolic process) and several hundreds to several thousands (oxidative stress process) photons s(-1)cm(-2). Current development in detection using low-noise photomultiplier tubes and imaging using highly sensitive charge coupled device cameras allows temporal and spatial visualization of oxidative metabolic or oxidative stress processes, respectively. As the phenomenon of ultra-weak photon emission reflects oxidative metabolic or oxidative stress processes, it can be widely used as a non-invasive tool for monitoring of the physiological state of biological systems. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Chemical Diversity and Biological Properties of Secondary Metabolites from Sea Hares of Aplysia Genus

    PubMed Central

    Pereira, Renato B.; Andrade, Paula B.; Valentão, Patrícia

    2016-01-01

    The marine environment is an important source of structurally-diverse and biologically-active secondary metabolites. During the last two decades, thousands of compounds were discovered in marine organisms, several of them having inspired the development of new classes of therapeutic agents. Marine mollusks constitute a successful phyla in the discovery of new marine natural products (MNPs). Over a 50-year period from 1963, 116 genera of mollusks contributed innumerous compounds, Aplysia being the most studied genus by MNP chemists. This genus includes 36 valid species and should be distinguished from all mollusks as it yielded numerous new natural products. Aplysia sea hares are herbivorous mollusks, which have been proven to be a rich source of secondary metabolites, mostly of dietary origin. The majority of secondary metabolites isolated from sea hares of the genus Aplysia are halogenated terpenes; however, these animals are also a source of compounds from other chemical classes, such as macrolides, sterols and alkaloids, often exhibiting cytotoxic, antibacterial, antifungal, antiviral and/or antifeedant activities. This review focuses on the diverse structural classes of secondary metabolites found in Aplysia spp., including several compounds with pronounced biological properties. PMID:26907303

  4. Physical and biological properties of U. S. standard endotoxin EC after exposure to ionizing radiation

    SciTech Connect

    Csako, G.; Elin, R.J.; Hochstein, H.D.; Tsai, C.M.

    1983-07-01

    Techniques that reduce the toxicity of bacterial endotoxins are useful for studying the relationship between structure and biological activity. We used ionizing radiation to detoxify a highly refined endotoxin preparation. U.S. standard endotoxin EC. Dose-dependent changes occurred by exposure to /sup 60/Co-radiation in the physical properties and biological activities of the endotoxin. Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis showed gradual loss of the polysaccharide components (O-side chain and R-core) from the endotoxin molecules. In contrast, although endotoxin revealed a complex absorption pattern in the UV range, radiation treatment failed to modify that pattern. Dose-related destruction of the primary toxic component, lipid A, was suggested by the results of activity tests: both the pyrogenicity and limulus reactivity of the endotoxin were destroyed by increasing doses of radiation. The results indicate that the detoxification is probably due to multiple effects of the ionizing radiation on bacterial lipopolysaccharides, and the action involves (i) the destruction of polysaccharide moieties and possibly (ii) the alteration of lipid A component of the endotoxin molecule.

  5. Structural parameters, molecular properties, and biological evaluation of some terpenes targeting Schistosoma mansoni parasite.

    PubMed

    Mafud, Ana C; Silva, Marcos P N; Monteiro, Daniela C; Oliveira, Maria F; Resende, João G; Coelho, Mayara L; de Sousa, Damião P; Mendonça, Ronaldo Z; Pinto, Pedro L S; Freitas, Rivelilson M; Mascarenhas, Yvonne P; de Moraes, Josué

    2016-01-25

    The use of natural products has a long tradition in medicine, and they have proven to be an important source of lead compounds in the development of new drugs. Among the natural compounds, terpenoids present broad-spectrum activity against infective agents such as viruses, bacteria, fungi, protozoan and helminth parasites. In this study, we report a biological screening of 38 chemically characterized terpenes from different classes, which have a hydroxyl group connected by hydrophobic chain or an acceptor site, against the blood fluke Schistosoma mansoni, the parasite responsible for schistosomiasis mansoni. In vitro bioassays revealed that 3,7-dimethyl-1-octanol (dihydrocitronellol) (10) was the most active terpene (IC50 values of 13-52 μM) and, thus, we investigated its antischistosomal activity in greater detail. Confocal laser scanning microscopy revealed that compound 10 induced severe tegumental damage in adult schistosomes and a correlation between viability and tegumental changes was observed. Furthermore, we compared all the inactive compounds with dihydrocitronellol structurally by using shape and charge modeling. Lipophilicity (miLogP) and other molecular properties (e.g. molecular polar surface area, molecular electrostatic potential) were also calculated. From the 38 terpenes studied, compound 10 is the one with the greatest flexibility, with a sufficient apolar region by which it may interact in a hydrophobic active site. In conclusion, the integration of biological and chemical analysis indicates the potential of the terpene dihydrocitronellol as an antiparasitic agent.

  6. Effect of sub-pore scale morphology of biological deposits on porous media flow properties

    NASA Astrophysics Data System (ADS)

    Ghezzehei, T. A.

    2012-12-01

    Biological deposits often influence fluid flow by altering the pore space morphology and related hydrologic properties such as porosity, water retention characteristics, and permeability. In most coupled-processes models changes in porosity are inferred from biological process models using mass-balance. The corresponding evolution of permeability is estimated using (semi-) empirical porosity-permeability functions such as the Kozeny-Carman equation or power-law functions. These equations typically do not account for the heterogeneous spatial distribution and morphological irregularities of the deposits. As a result, predictions of permeability evolution are generally unsatisfactory. In this presentation, we demonstrate the significance of pore-scale deposit distribution on porosity-permeability relations using high resolution simulations of fluid flow through a single pore interspersed with deposits of varying morphologies. Based on these simulations, we present a modification to the Kozeny-Carman model that accounts for the shape of the deposits. Limited comparison with published experimental data suggests the plausibility of the proposed conceptual model.

  7. Force per cross-sectional area from molecules to muscles: a general property of biological motors.

    PubMed

    Rospars, Jean-Pierre; Meyer-Vernet, Nicole

    2016-07-01

    We propose to formally extend the notion of specific tension, i.e. force per cross-sectional area-classically used for muscles, to quantify forces in molecular motors exerting various biological functions. In doing so, we review and compare the maximum tensions exerted by about 265 biological motors operated by about 150 species of different taxonomic groups. The motors considered range from single molecules and motile appendages of microorganisms to whole muscles of large animals. We show that specific tensions exerted by molecular and non-molecular motors follow similar statistical distributions, with in particular, similar medians and (logarithmic) means. Over the 10(19) mass (M) range of the cell or body from which the motors are extracted, their specific tensions vary as M(α) with α not significantly different from zero. The typical specific tension found in most motors is about 200 kPa, which generalizes to individual molecular motors and microorganisms a classical property of macroscopic muscles. We propose a basic order-of-magnitude interpretation of this result.

  8. Proton and gallium(III) binding properties of a biologically active salicylidene acylhydrazide.

    PubMed

    Hakobyan, Shoghik; Boily, Jean-François; Ramstedt, Madeleine

    2014-09-01

    Bacterial biofilm formation causes a range of problems in our society, especially in health care. Salicylidene acylhydrazides (hydrazones) are promising antivirulence drugs targeting secretion systems used during bacterial infection of host cells. When mixed with the gallium ion they become especially potent as bacterial and biofilm growth-suppressing agents, although the mechanisms through which this occurs are not fully understood. At the base of this uncertainty lies the nature of hydrazone-metal interactions. This study addresses this issue by resolving the equilibrium speciation of hydrazone-gallium aqueous solutions. The protonation constants of the target 2-oxo-2-[N-(2,4,6-trihydroxy-benzylidene)-hydrazino]-acetamide (ME0163) hydrazone species and of its 2,4,6-trihydroxybenzaldehyde and oxamic acid hydrazide building blocks were determined by UV-visible spectrophotometry to achieve this goal. These studies show that the hydrazone is an excessively strong complexing agent for gallium and that its antivirulence properties are predominantly ascribed to monomeric 1:1Ga-ME0163 complexes of various Ga hydrolysis and ME0163 protonation states. The chelation of Ga(III) to the hydrazone also increased the stability of the compounds against acid-induced hydrolysis, making this group of compounds very interesting for biological applications where the Fe-antagonist action of both Ga(III) and the hydrazone can be combined for enhanced biological effect. Copyright © 2014. Published by Elsevier Inc.

  9. Optical and biological properties of transparent nanocrystalline hydroxyapatite obtained through spark plasma sintering.

    PubMed

    Li, Zhong; Thompson, Brianna C; Dong, Zhili; Khor, Khiam Aik

    2016-12-01

    Transparent bioceramics have attracted a large amount of research interest as they facilitate direct observation of biointerfacial reactions. Thus far, attempts to achieve transparent hydroxyapatite have been focused on augmenting the sintering pressure and/or extending the sintering duration. This study aims at fabricating transparent HA using a direct and fast spark plasma sintering process with appropriate starting powder and moderate sintering pressure. Three types of raw powder, namely micro-spheres, nano-rods and nano-spheres, were sintered to investigate the optical and biological properties of the compacted pellets. It was found that in terms of transparency, the micro-sphere pellet sintered at 1000°C stood out with an in-line transmittance as high as 84% achieved at 1300nm for a 2mm thick sample. In addition, pellets fabricated from micro-spheres demonstrated the highest cell viability in in vitro biological tests with L929 cells. Living cells cultured on a transparent micro-sphere pellet could be directly and clearly observed by light microscopy. It is thus concluded that the micro-sphere powder is the most desirable raw material to manufacture transparent hydroxyapatite because it could enable dense pellets with notably high transparency and outstanding in vitro biocompatibility to be readily obtained.

  10. Functionalized Polymeric Membrane with Enhanced Mechanical and Biological Properties to Control the Degradation of Magnesium Alloy.

    PubMed

    Wong, Hoi Man; Zhao, Ying; Leung, Frankie K L; Xi, Tingfei; Zhang, Zhixiong; Zheng, Yufeng; Wu, Shuilin; Luk, Keith D K; Cheung, Kenneth M C; Chu, Paul K; Yeung, Kelvin W K

    2017-04-01

    To achieve enhanced biological response and controlled degradation of magnesium alloy, a modified biodegradable polymer coating called polycaprolactone (PCL) is fabricated by a thermal approach in which the heat treatment neither alters the chemical composition of the PCL membrane nor the rate of magnesium ion release, pH value, or weight loss, compared with the untreated sample. The changes in the crystallinity, hydrophilicity, and oxygen content of heat-treated PCL coating not only improve the mechanical adhesion strength between the coating and magnesium substrate but also enhance the biological properties. Moreover, the thermally modified sample can lead to higher spreading and elongation of osteoblasts, due to the enhanced hydrophilicity and CO to CO functional group ratio. In the analyses of microcomputed tomography from one to four weeks postoperation, the total volume of new bone formation on the heat-treated sample is 10%-35% and 70%-90% higher than that of the untreated and uncoated controls, respectively. Surprisingly, the indentation modulus of the newly formed bone adjacent to the heat-treated sample is ≈20% higher than that of both controls. These promising results reveal the clinical potential of the modified PCL coating on magnesium alloy in orthopedic applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Chemical Diversity and Biological Properties of Secondary Metabolites from Sea Hares of Aplysia Genus.

    PubMed

    Pereira, Renato B; Andrade, Paula B; Valentão, Patrícia

    2016-02-19

    The marine environment is an important source of structurally-diverse and biologically-active secondary metabolites. During the last two decades, thousands of compounds were discovered in marine organisms, several of them having inspired the development of new classes of therapeutic agents. Marine mollusks constitute a successful phyla in the discovery of new marine natural products (MNPs). Over a 50-year period from 1963, 116 genera of mollusks contributed innumerous compounds, Aplysia being the most studied genus by MNP chemists. This genus includes 36 valid species and should be distinguished from all mollusks as it yielded numerous new natural products. Aplysia sea hares are herbivorous mollusks, which have been proven to be a rich source of secondary metabolites, mostly of dietary origin. The majority of secondary metabolites isolated from sea hares of the genus Aplysia are halogenated terpenes; however, these animals are also a source of compounds from other chemical classes, such as macrolides, sterols and alkaloids, often exhibiting cytotoxic, antibacterial, antifungal, antiviral and/or antifeedant activities. This review focuses on the diverse structural classes of secondary metabolites found in Aplysia spp., including several compounds with pronounced biological properties.

  12. Biological properties of water-soluble polysaccharides and hemicelluloses from almond gum.

    PubMed

    Bouaziz, Fatma; Koubaa, Mohamed; Ellouz Ghorbel, Rhoudha; Ellouz Chaabouni, Semia

    2017-02-01

    The aim of this work was to investigate the biological activities of almond gum polysaccharides (AGP) and almond gum hemicelluloses (AGH). Almond gum was first fractionated into AGP and AGH using hot water and alkaline solution, respectively. The antioxidant activities of both extracted polymers revealed interesting free radical scavenging activities through DPPH test (IC50 AGP=4mg/mL, IC50 AGH=6mg/mL), 2,2'-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) radical scavenging activity test (% inhibition ABTS=40.53±1.99% and 87.14±1% for AGP and AGH, respectively), reducing power capacity (RPAGP=20mg/mL, RPAGH=1.1mg/mL), and β-carotene bleaching inhibition (IC50AGP=18.5mg/mL, IC50AGH 0.8mg/mL). Antibacterial activities of both polymers were tested against pathogenic strains showing interesting growth inhibition. Moreover, AGP and AGH were also efficient to inhibit ACE; the angiotensin converting enzyme (at 1mg/mL, the ACE inhibitory activity was 75.81±1.53% and 90.86±2.47%, respectively). The results obtained in this study demonstrate the attractive biological properties of fractions obtained from almond gum and their potential to be used in numerous food and non-food applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Mechanical properties and biological interaction of aortic clamps: are these all minimally invasive?

    PubMed

    Bianchi, Giacomo; Pucci, Angela; Matteucci, Marco; Varone, Egidio; Romano, Simone Lorenzo; Lionetti, Vincenzo; Glauber, Mattia

    2013-01-01

    Although specifically designed aortic clamps are mainstay of minimally invasive cardiac surgery, so far, no comparative reports about their mechanical properties and interaction with the aortic wall have been reported. In this study, the generated force in the clamps' jaws and the biological response of the aorta after clamping are evaluated. The jaw force of five commercially available clamps [Geister, Cygnet, Cardiovision (CV) 195.10, CV 195.40, and CV 195.83] was assessed by clamping a 2.2-mm compression load cell with a dedicated computer universal serial bus interface at the proximal, the middle, and the distal site from the fulcrum. Biological response of the aortic wall was assessed in five minipigs (weight, 38-40 kg) that underwent thoracic aorta clamping and leakage point test. Immunohistochemistry and morphometric analysis were carried out for each aortic segment tested. Force generation pattern is peculiar of each clamp, being higher in the proximal and the middle portion and lower in the distal part. One clamp (Cygnet) exhibited homogeneous maximal force generation at all three sites. All clamps exhibited peculiar crushing artifacts. A variable degree of endothelial layer disruption occurred in all clamping tests; three clamps (CV 195.10, Cygnet, and Geister) had the lower amount of intact endothelium. The clamping force was not associated with the degree of endothelial disruption (P value was not significant). The choice of a clamp that is not only minimally invasive in design but also least traumatic will help avoid complications of aortic manipulation.

  14. Effects of cellular homeostatic intrinsic plasticity on dynamical and computational properties of biological recurrent neural networks.

    PubMed

    Naudé, Jérémie; Cessac, Bruno; Berry, Hugues; Delord, Bruno

    2013-09-18

    Homeostatic intrinsic plasticity (HIP) is a ubiquitous cellular mechanism regulating neuronal activity, cardinal for the proper functioning of nervous systems. In invertebrates, HIP is critical for orchestrating stereotyped activity patterns. The functional impact of HIP remains more obscure in vertebrate networks, where higher order cognitive processes rely on complex neural dynamics. The hypothesis has emerged that HIP might control the complexity of activity dynamics in recurrent networks, with important computational consequences. However, conflicting results about the causal relationships between cellular HIP, network dynamics, and computational performance have arisen from machine-learning studies. Here, we assess how cellular HIP effects translate into collective dynamics and computational properties in biological recurrent networks. We develop a realistic multiscale model including a generic HIP rule regulating the neuronal threshold with actual molecular signaling pathways kinetics, Dale's principle, sparse connectivity, synaptic balance, and Hebbian synaptic plasticity (SP). Dynamic mean-field analysis and simulations unravel that HIP sets a working point at which inputs are transduced by large derivative ranges of the transfer function. This cellular mechanism ensures increased network dynamics complexity, robust balance with SP at the edge of chaos, and improved input separability. Although critically dependent upon balanced excitatory and inhibitory drives, these effects display striking robustness to changes in network architecture, learning rates, and input features. Thus, the mechanism we unveil might represent a ubiquitous cellular basis for complex dynamics in neural networks. Understanding this robustness is an important challenge to unraveling principles underlying self-organization around criticality in biological recurrent neural networks.

  15. Force per cross-sectional area from molecules to muscles: a general property of biological motors

    PubMed Central

    Meyer-Vernet, Nicole

    2016-01-01

    We propose to formally extend the notion of specific tension, i.e. force per cross-sectional area—classically used for muscles, to quantify forces in molecular motors exerting various biological functions. In doing so, we review and compare the maximum tensions exerted by about 265 biological motors operated by about 150 species of different taxonomic groups. The motors considered range from single molecules and motile appendages of microorganisms to whole muscles of large animals. We show that specific tensions exerted by molecular and non-molecular motors follow similar statistical distributions, with in particular, similar medians and (logarithmic) means. Over the 1019 mass (M) range of the cell or body from which the motors are extracted, their specific tensions vary as Mα with α not significantly different from zero. The typical specific tension found in most motors is about 200 kPa, which generalizes to individual molecular motors and microorganisms a classical property of macroscopic muscles. We propose a basic order-of-magnitude interpretation of this result. PMID:27493785

  16. Chemical and Biological Properties of S-1-Propenyl-l-Cysteine in Aged Garlic Extract.

    PubMed

    Kodera, Yukihioro; Ushijima, Mitsuyasu; Amano, Hirotaka; Suzuki, Jun-Ichiro; Matsutomo, Toshiaki

    2017-03-31

    S-1-Propenyl-l-cysteine (S1PC) is a stereoisomer of S-1-Propenyl-l-cysteine (SAC), an important sulfur-containing amino acid that plays a role for the beneficial pharmacological effects of aged garlic extract (AGE). The existence of S1PC in garlic preparations has been known since the 1960's. However, there was no report regarding the biological and/or pharmacological activity of S1PC until 2016. Recently, we performed a series of studies to examine the chemical, biological, pharmacological and pharmacokinetic properties of S1PC, and obtained some interesting results. S1PC existed only in trace amounts in raw garlic, but its concentration increased almost up to the level similar of SAC through aging process of AGE. S1PC showed immunomodulatory effects in vitro and in vivo, and reduced blood pressure in a hypertensive animal model. A pharmacokinetic study revealed that S1PC was readily absorbed after oral administration in rats and dogs with bioavailability of 88-100%. Additionally, S1PC had little inhibitory influence on human cytochrome P450 activities, even at a concentration of 1 mM. Based on these findings, S1PC was suggested to be another important, pharmacologically active and safe component of AGE similar to SAC. In this review, we highlight some results from recent studies on S1PC and discuss the potential medicinal value of S1PC.

  17. Phospholipid hydroxyalkenals: biological and chemical properties of specific oxidized lipids present in atherosclerotic lesions.

    PubMed

    Hoff, Henry F; O'Neil, June; Wu, Zhiping; Hoppe, George; Salomon, Robert L

    2003-02-01

    Phosphatidylcholine hydroxyalkenals (PC-HAs) are a class of oxidized PCs derived from lipid peroxidation of arachidonate or linoleate at the sn-2 position to form terminal gamma-hydroxy, alpha-, and beta-unsaturated aldehydes. The aim of this study was to characterize some of their biological properties, ascertain the mechanism of their action, and assess whether they have in vivo relevance. Combinations of cell biological approaches with radiolabels, mass spectroscopy, and immunochemical as well as immunohistochemical techniques were used to show that PC-HAs reduce the proteolytic degradation by mouse peritoneal macrophages (MPMs) of internalized macromolecules, such as maleylated bovine serum albumin, and that the activity of the lysosomal protease, cathepsin B, in MPMs form Michael adducts with MPM proteins and with N-acetylated cysteine in vitro form pyrrole adducts with MPM proteins and reduce the maturation of Rab5a, thereby impairing phagosome-lysosome fusion (maturation) in phagocytes; they are present unbound and as pyrrole adducts in human atherosclerotic lesions. PC-HAs are present in vivo and possess multiple functions characteristic of oxidized LDL and 4-hydroxynonenal.

  18. Microparticulated and nanoparticulated zirconium oxide added to calcium silicate cement: Evaluation of physicochemical and biological properties.

    PubMed

    Silva, Guilherme F; Bosso, Roberta; Ferino, Rafael V; Tanomaru-Filho, Mário; Bernardi, Maria I B; Guerreiro-Tanomaru, Juliane M; Cerri, Paulo S

    2014-12-01

    The physicochemical and biological properties of calcium silicate-based cement (CS) associated to microparticulated (micro) or nanoparticulated (nano) zirconium oxide (ZrO2 ) were compared with CS and bismuth oxide (BO) with CS. The pH, release of calcium ions, radiopacity, setting time, and compression strength of the materials were evaluated. The tissue reaction promoted by these materials in the subcutaneous was also investigated by morphological, immunohistochemical, and quantitative analyses. For this purpose, polyethylene tubes filled with materials were implanted into rat subcutaneous. After 7, 15, 30, and 60 days, the tubes surrounded by capsules were fixed and embedded in paraffin. In the H&E-stained sections, the number of inflammatory cells (ICs) in the capsule was obtained. Moreover, detection of interleukin-6 (IL-6) by immunohistochemistry and number of IL-6 immunolabeled cells were carried out. von Kossa method was also performed. The differences among the groups were subjected to Tukey test (p ≤ 0.05). The solutions containing the materials presented an alkaline pH and released calcium ions. The addition of radiopacifiers increased setting time and radiopacity of CS. A higher compressive strength in the CS + ZrO2 (micro and nano) was found compared with CS + BO. The number of IC and IL-6 positive cells in the materials with ZrO2 was significantly reduced in comparison with CS + BO. von Kossa-positive structures were observed adjacent to implanted materials. The ZrO2 associated to the CS provides satisfactory physicochemical properties and better biological response than BO. Thus, ZrO2 may be a good alternative for use as radiopacifying agent in substitution to BO.

  19. Thermoacoustic and photoacoustic imaging of biological tissue with different contrasts and properties

    NASA Astrophysics Data System (ADS)

    Nie, Liming; Guo, Hua

    2008-12-01

    Microwave-induced thermoacoustic or photoacoustic imaging is a nonionizing imaging modality based on the difference in microwave or light absorption of various biological tissues. The advantage of this imaging over traditional optical imaging is that it retains intrinsic microwave or optical contrast characteristics while benefiting from the diffraction-limited high spatial resolution of ultrasound. Various tissues present particular characteristics in their absorption spectra. Photoacoustic imaging can map optical absorption distribution whereas microwave-induced thermoacoustic imaging is related to the electrical properties in the objects. Muscles which have a rich blood supply provide excellent optical contrast. In contrast high water or ion content tissues, such as muscle tissues or malignant tissues, demonstrate high contrast to fatty tissues employing microwave radiation. Besides different contrast mechanisms, microwave-induced thermoacoustic imaging may find unique applications because microwave radiation provides a deeper penetration depth in biological tissues than optical radiation. The frequency spectrum of thermoacoustic images is much lower and the spatial resolution is poorer due to the pulse width of microwave radiation. Therefore, thermoacoustic and photoacoustic imaging are associated with different characteristics based on information from tissue properties over an electromagnetic spectrum from microwave to optical bands. The reconstructed thermoacoustic and photoacoustic images with their image blending may be more accurate and comprehensive than was previously available. Also the experimental results show that breast cancer detection is a promising, and specific application field by microwave-induced thermoacoustic imaging. We are able to provide multimodality, complementary, and low cost images which can be potentially used for early cancer detection and imaging.

  20. Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction.

    PubMed

    Sivagnanam, Saravana Periaswamy; Yin, Shipeng; Choi, Jae Hyung; Park, Yong Beom; Woo, Hee Chul; Chun, Byung Soo

    2015-05-29

    The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO2 (SC-CO2) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO2 method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO2 (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO2 oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO2. The acetone-methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO2 extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.

  1. Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction

    PubMed Central

    Periaswamy Sivagnanam, Saravana; Yin, Shipeng; Choi, Jae Hyung; Park, Yong Beom; Woo, Hee Chul; Chun, Byung Soo

    2015-01-01

    The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO2 (SC-CO2) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO2 method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO2 (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO2 oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO2. The acetone–methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO2 extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process. PMID:26035021

  2. Biologic and immunomodulatory properties of mesenchymal stromal cells derived from human pancreatic islets

    PubMed Central

    KIM, JAEHYUP; BREUNIG, MELISSA J.; ESCALANTE, LEAH E.; BHATIA, NEEHAR; DENU, RYAN A.; DOLLAR, BRIDGET A.; STEIN, ANDREW P.; HANSON, SUMMER E.; NADERI, NADIA; RADEK, JAMES; HAUGHY, DERMOT; BLOOM, DEBRA D.; ASSADI-PORTER, FARIBA M.; HEMATTI, PEIMAN

    2012-01-01

    Background aims Mesenchymal stromal cells (MSC) have now been shown to reside in numerous tissues throughout the body, including the pancreas. Ex vivo culture-expanded MSC derived from many tissues display important interactions with different types of immune cells in vitro and potentially play a significant role in tissue homeostasis in vivo. In this study, we investigated the biologic and immunomodulatory properties of human pancreatic islet-derived MSC. Methods We culture-expanded MSC from cadaveric human pancreatic islets and characterized them using flow cytometry, differentiation assays and nuclear magnetic resonance-based metabolomics. We also investigated the immunologic properties of pancreatic islet-derived MSC compared with bone marrow (BM) MSC. Results Pancreatic islet and BM-derived MSC expressed the same cell-surface markers by flow cytometry, and both could differentiate into bone, fat and cartilage. Metabolomics analysis of MSC from BM and pancreatic islets also showed a similar set of metabolic markers but quantitative polymerase chain reactions showed that pancreatic islet MSC expressed more interleukin(IL)-1b, IL-6, STAT3 and FGF9 compared with BM MSC, and less IL-10. However, similar to BM MSC, pancreatic islet MSC were able to suppress proliferation of allogeneic T lymphocytes stimulated with anti-CD3 and anti-CD28 antibodies. Conclusions Our in vitro analysis shows pancreatic islet-derived MSC have phenotypic, biologic and immunomodulatory characteristics similar, but not identical, to BM-derived MSC. We propose that pancreatic islet-derived MSC could potentially play an important role in improving the outcome of pancreatic islet transplantation by promoting engraftment and creating a favorable immune environment for long-term survival of islet allografts. PMID:22571381

  3. Physico-chemical properties of hydrophilic and amphiphilic crosslinked systems that influence biological responses

    NASA Astrophysics Data System (ADS)

    Ejiasi, Angel

    The effect of physical, chemical, and biological cues on the behavior of smooth muscle cells (SMCs) and attachment of marine organisms was investigated. Both hydrophilic and amphiphilic crosslinked polymer networks with varying chemical and mechanical properties were used to direct biological responses. Poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels were fabricated with tunable mechanical properties by varying the di-functional monomer concentration in the feed composition. Amphiphilic hydrogels composed of 2-hydroxyethyl methacrylate (HEMA), 1,3-bis(3-methacryloxypropyl)tetrakis(trimethylsiloxy)disiloxane (MPTSDS), and tris(trimethylsiloxy)-3-methacryloxypropylsilane (TRIS) were copolymerized using ultraviolet (UV) light and a photo-initiator. Hydrogels prepared with varying concentration of di-functional monomer, MPTSDS, exhibited an order of magnitude difference in elastic moduli. Not only were the bulk material properties influenced by the crosslinking agent concentration in the feed composition, but the surface properties (i.e., contact angle and hysteresis) were influenced as well. Modulus (E) has been reported to be positively correlated with the settlement of marine organisms. However, this was not the case for the amphiphilic gels tested against biomolecules and marine organisms. Stiffer gels inhibited fouling of proteins and marine organism, Ulva linza, to a greater extent than the softer gels. Furthermore, the network structure, in regards to the molecular weight between crosslinks Mc, was found to have a greater influence on fouling. A strong correlation was observed between protein adsorption and Mc of the amphiphilic crosslinked networks compared to just the modulus and surface energy (Upsilon) alone. A higher correlation was also obtained between Mc and Ulva sporeling biomass than between sporeling biomass and elastic modulus E, exhibiting R² value of 0.98 and 0.38, respectively. The percent removal of sporeling biomass growth was shown to be

  4. Comparative analysis of housekeeping and tissue-selective genes in human based on network topologies and biological properties.

    PubMed

    Yang, Lei; Wang, Shiyuan; Zhou, Meng; Chen, Xiaowen; Zuo, Yongchun; Sun, Dianjun; Lv, Yingli

    2016-06-01

    Housekeeping genes are genes that are turned on most of the time in almost every tissue to maintain cellular functions. Tissue-selective genes are predominantly expressed in one or a few biologically relevant tissue types. Benefitting from the massive gene expression microarray data obtained over the past decades, the properties of housekeeping and tissue-selective genes can now be investigated on a large-scale manner. In this study, we analyzed the topological properties of housekeeping and tissue-selective genes in the protein-protein interaction (PPI) network. Furthermore, we compared the biological properties and amino acid usage between these two gene groups. The results indicated that there were significant differences in topological properties between housekeeping and tissue-selective genes in the PPI network, and housekeeping genes had higher centrality properties and may play important roles in the complex biological network environment. We also found that there were significant differences in multiple biological properties and many amino acid compositions. The functional genes enrichment and subcellular localizations analysis was also performed to investigate the characterization of housekeeping and tissue-selective genes. The results indicated that the two gene groups showed significant different enrichment in drug targets, disease genes and toxin targets, and located in different subcellular localizations. At last, the discriminations between the properties of two gene groups were measured by the F-score, and expression stage had the most discriminative index in all properties. These findings may elucidate the biological mechanisms for understanding housekeeping and tissue-selective genes and may contribute to better annotate housekeeping and tissue-selective genes in other organisms.

  5. Biological properties of carbon/carbon implant composites with unique manufacturing processes.

    PubMed

    Wang, Guo-Hui; Yu, Shu; Zhu, Shai-Hong; Gao, Chang-Qing; Liu, Yong; Miu, Yun-Liang; Huang, Bo-Yun

    2009-12-01

    The goal was to manufacture carbon/carbon (C/C) composites through a unique procedure with improved biocompatibility and reduced debris release. C/C composites were prepared by chemical vapor deposition, and their biological properties were analyzed. With regard to mechanical properties, compressive strength/modulus was 219.1 MPa/9.72 GPa, flexural strength/modulus was 121.63 MPa/21.9 GPa, and interlaminar sheer was 15.13 GPa. Biocompatibility testing revealed: (1) the extract liquid from the C/C composites had no effect on cell proliferation; (2) the extract had no impact on micronucleus frequency as compared with the control groups (P > 0.05); (3) in vivo, there was mild tissue inflammation after implantation within the first 2 weeks, but there was no significant difference compared with the control group (P > 0.05); (4) the implants were well integrated into the host tissue, and debris was limited. The tested samples have excellent biocompatibilities and reduced release of debris. The demonstrated changes in manufacturing procedures are promising.

  6. Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties

    PubMed Central

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Joshua Pfefer, T.

    2016-01-01

    Abstract. Established medical imaging technologies such as magnetic resonance imaging and computed tomography rely on well-validated tissue-simulating phantoms for standardized testing of device image quality. The availability of high-quality phantoms for optical-acoustic diagnostics such as photoacoustic tomography (PAT) will facilitate standardization and clinical translation of these emerging approaches. Materials used in prior PAT phantoms do not provide a suitable combination of long-term stability and realistic acoustic and optical properties. Therefore, we have investigated the use of custom polyvinyl chloride plastisol (PVCP) formulations for imaging phantoms and identified a dual-plasticizer approach that provides biologically relevant ranges of relevant properties. Speed of sound and acoustic attenuation were determined over a frequency range of 4 to 9 MHz and optical absorption and scattering over a wavelength range of 400 to 1100 nm. We present characterization of several PVCP formulations, including one designed to mimic breast tissue. This material is used to construct a phantom comprised of an array of cylindrical, hemoglobin-filled inclusions for evaluation of penetration depth. Measurements with a custom near-infrared PAT imager provide quantitative and qualitative comparisons of phantom and tissue images. Results indicate that our PVCP material is uniquely suitable for PAT system image quality evaluation and may provide a practical tool for device validation and intercomparison. PMID:26886681

  7. Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties

    NASA Astrophysics Data System (ADS)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Joshua Pfefer, T.

    2016-10-01

    Established medical imaging technologies such as magnetic resonance imaging and computed tomography rely on well-validated tissue-simulating phantoms for standardized testing of device image quality. The availability of high-quality phantoms for optical-acoustic diagnostics such as photoacoustic tomography (PAT) will facilitate standardization and clinical translation of these emerging approaches. Materials used in prior PAT phantoms do not provide a suitable combination of long-term stability and realistic acoustic and optical properties. Therefore, we have investigated the use of custom polyvinyl chloride plastisol (PVCP) formulations for imaging phantoms and identified a dual-plasticizer approach that provides biologically relevant ranges of relevant properties. Speed of sound and acoustic attenuation were determined over a frequency range of 4 to 9 MHz and optical absorption and scattering over a wavelength range of 400 to 1100 nm. We present characterization of several PVCP formulations, including one designed to mimic breast tissue. This material is used to construct a phantom comprised of an array of cylindrical, hemoglobin-filled inclusions for evaluation of penetration depth. Measurements with a custom near-infrared PAT imager provide quantitative and qualitative comparisons of phantom and tissue images. Results indicate that our PVCP material is uniquely suitable for PAT system image quality evaluation and may provide a practical tool for device validation and intercomparison.

  8. Compatible solutes: Thermodynamic properties and biological impact of ectoines and prolines.

    PubMed

    Held, Christoph; Neuhaus, Thorsten; Sadowski, Gabriele

    2010-11-01

    Compatible solutes like ectoine and its derivatives are deployed by halophile organisms as osmolytes to sustain the high salt concentration in the environment. This work investigates the relation of the thermodynamic properties of compatible solutes and their impact as osmolytes. The ectoines considered in this work are ectoine, hydroxyectoine, and homoectoine. Besides solution densities (15-45°C) and solubilities in water (3-80°C), component activity coefficients in the aqueous solutions were determined in the temperature range between 0 and 50°C. The latter is important for adjusting a certain water activity and therewith a respective osmotic pressure within a cell. The characteristic effect of ectoines is compared to that of prolines, as well as to that of incompatible solutes as salts and urea. The experimental results show that the influence on the activity (coefficient) of water is quite different for compatible and incompatible solutes: whereas compatible solutes cause decreasing water activity coefficients, incompatible solutes lead to an increase in water activity coefficients. Based on this quantity, the paper discusses the impact of various osmolytes on biological systems and contributes to the explanation why some osmolytes are more often and at other temperatures used than others. Moreover, it was found that the anti-stress effect of an osmolyte is weakened in the presence of a salt. Finally, it is shown that the thermodynamic properties of compatible solutes can be modeled and even predicted using the thermodynamic model PC-SAFT (Perturbed-Chain Statistical Associating Fluid Theory).

  9. Biological properties and biodegradation studies of chitosan biofilms plasticized with PEG and glycerol.

    PubMed

    Kammoun, Maher; Haddar, Manel; Kallel, Tasnim Kossentini; Dammak, Mohamed; Sayari, Adel

    2013-11-01

    Chitosan biofilms, prepared by casting method at various percentage of plasticizer (PEG and glycerol), were evaluated for their biological, structural and thermal properties. The addition of PEG at 30% (w/w) and glycerol at 10% (w/w) to chitosan has increased the antioxidant activity of biofilm with the percentages of 22 and 26%, respectively. The increase of ferric reducing power was noted for the mixtures of chitosan-PEG (70-30) and chitosan-GLY (75-25). Additionally, the antibacterial properties of several biofilms were tested against E. coli and S. aureus. Biofilms with 70-30 and 90-10 blends ratio of chitosan-PEG and chitosan-GLY showed the best inhibitory effect against E. coli and S. aureus with 12 and 27%, respectively. All biofilms were degraded in compost in liquid and the addition of plasticizer PEG to chitosan increased his biodegradability with a value of BOD5 about 2.33 O2/mg CO. FT-IR spectra showed that the addition of plasticizer promoted the interactions through hydrogen bonding as reflected on the shifting of main peaks but there is no effect on biodegradation.

  10. An optimized molecular inclusion complex of diferuloylmethane: enhanced physical properties and biological activity

    PubMed Central

    Tan, Qunyou; Li, Yi; Wu, Jianyong; Mei, Hu; Zhao, Chunjing; Zhang, Jingqing

    2012-01-01

    Objective The purpose of this study was to explore and evaluate the enhanced physical properties and biological activity of a molecular inclusion complex (MICDH) comprising diferuloylmethane (DFM) and hydroxypropyl-β-cyclodextrin. Methods The preparation conditions of MICDH were optimized using an orthogonal experimental design. The solubility, in vitro release and model fitting, microscopic morphology, molecular structure simulation, anti-lung cancer activity, and action mechanism of MICDH were evaluated. Results The solubility of DFM was improved 4400-fold upon complexation with hydroxypropyl-β-cyclodextrin. The release rate of DFM was significantly higher from MICDH than from free DFM. MICDH exhibited higher antitumor activity against human lung adenocarcinoma A549 cells than free DFM. More cells were arrested in the S/G2 phase of the cell cycle or were induced to undergo apoptosis when treated with MICDH than when treated with free DFM. Furthermore, increased reactive oxygen species and intracellular calcium ion levels and decreased mitochondrial membrane potential were observed in cells treated with MICDH. Conclusion MICDH markedly improved the physical properties and antitumor activity of DFM. MICDH may prove to be a preferred alternative to free DFM as a formulation for DFM delivery in lung cancer treatment. PMID:23091376

  11. ZnO nanostructure fabrication in different solvents transforms physio-chemical, biological and photodegradable properties.

    PubMed

    Ali, Attarad; Ambreen, Sidra; Javed, Rabia; Tabassum, Saira; Ul Haq, Ihsan; Zia, Muhammad

    2017-05-01

    Zinc oxide (ZnO) nanostructures are synthesized in various organic solvents (acetone, chloroform, ethyl acetate, ethanol and methanol) and water via coprecipitation process using zinc acetate as precursor. The resultant ZnO nanoparticles, nano rods and nano sheets are characterized by UV-vis spectrophotometric analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDX). The variable size and geometry of nanoparticles depend upon medium used for synthesis. The synthesized ZnO nanostructures exhibit minor to moderate antioxidative (DPPH based free radical scavenging activity, total antioxidative potential and total reducing power) response. Mild to moderate antibacterial and antifungal activities, excellent antileishmanial potential (IC50 up to 3.76), and good cytotoxic perspective (LD50 up to 49.4) is also observed by the synthesized ZnO NPs. The nanoparticles also exhibit moderate α-amylase inhibition response. Furthermore the nanostructures are evaluated for methylene blue photodegradation response within 60min time period. It is found that organic solvent alters shape, size and other physio-chemical properties of ZnO that ultimately modulate the biological, chemical, and environmental properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Biological properties of carotenoids extracted from Halobacterium halobium isolated from a Tunisian solar saltern.

    PubMed

    Abbes, Molka; Baati, Houda; Guermazi, Sonda; Messina, Concetta; Santulli, Andrea; Gharsallah, Neji; Ammar, Emna

    2013-10-04

    Bioactive molecules have received increasing attention due to their nutraceutical attributes and anticancer, antioxidant, antiproliferative and apoptosis-inducing properties. This study aimed to investigate the biological properties of carotenoids extracted from Archaea. Halophilic Archaea strains were isolated from the brine of a local crystallizer pond (TS7) of a solar saltern at Sfax, Tunisia. The most carotenoid-producing strain (M8) was investigated on heptoma cell line (HepG2), and its viability was assessed by the MTT-test. The cells were incubated with different sub-lethal extract rates, with carotenoid concentrations ranging from 0.2 to 1.5 μM. Antioxidant activity was evaluated through exposing the cells to sub-lethal extract concentrations for 24 hours and then to oxidative stress induced by 60 μM arachidonic acid and 50 μM H₂O₂. Compared to non-treated cells, bacterial carotenoid extracts inhibited HepG2 cell viability (50%). A time and dose effect was observed, with cell viability undergoing a significant (P < 0.05) decrease with extract concentration. After exposure to oxidative stress, control cells underwent a significant (P < 0.05) decrease in viability as compared to the non-treated cells. The bacterial extracts under investigation were noted to exhibit the strongest free radical scavenging activity with high carotenoid concentrations. The carotenoid extract also showed significant antiproliferative activity against HepG2 human cancer cell lines.

  13. Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties.

    PubMed

    Vogt, William C; Jia, Congxian; Wear, Keith A; Garra, Brian S; Joshua Pfefer, T

    2016-10-01

    Established medical imaging technologies such as magnetic resonance imaging and computed tomography rely on well-validated tissue-simulating phantoms for standardized testing of device image quality. The availability of high-quality phantoms for optical-acoustic diagnostics such as photoacoustic tomography (PAT) will facilitate standardization and clinical translation of these emerging approaches. Materials used in prior PAT phantoms do not provide a suitable combination of long-term stability and realistic acoustic and optical properties. Therefore, we have investigated the use of custom polyvinyl chloride plastisol (PVCP) formulations for imaging phantoms and identified a dual-plasticizer approach that provides biologically relevant ranges of relevant properties. Speed of sound and acoustic attenuation were determined over a frequency range of 4 to 9 MHz and optical absorption and scattering over a wavelength range of 400 to 1100 nm. We present characterization of several PVCP formulations, including one designed to mimic breast tissue. This material is used to construct a phantom comprised of an array of cylindrical, hemoglobin-filled inclusions for evaluation of penetration depth. Measurements with a custom near-infrared PAT imager provide quantitative and qualitative comparisons of phantom and tissue images. Results indicate that our PVCP material is uniquely suitable for PAT system image quality evaluation and may provide a practical tool for device validation and intercomparison.

  14. Comparing the mechanical properties of high performances polymer nanocomposites from biological sources.

    PubMed

    Dufresne, Alain

    2006-02-01

    There are numerous examples where animals or plants synthesize extracellular high-performance skeletal biocomposites consisting of a matrix reinforced by fibrous biopolymers. Cellulose and chitin are classical examples of these reinforcing elements, which occur as whisker-like microfibrils that are biosynthesized and deposited in a continuous fashion. In many cases, this mode of biogenesis leads to crystalline microfibrils that are almost defect-free, with the consequence of axial physical properties approaching those of perfect crystals. Starch is another example of natural semicrystalline polymer that is produced by many plants and occurs as microscopic granules. It acts as a storage polymer in cereals and tubers. These abundant and natural polymers can be used to create high performance nanocomposites presenting outstanding properties. Aqueous suspensions of crystallites can be prepared by acid hydrolysis of the purified substrates. The object of this treatment is to dissolve away regions of low lateral order so that the water-insoluble, highly crystalline residue may be converted into a stable suspension by subsequent vigorous mechanical shearing action. For cellulose and chitin, these monocrystals appear as rod-like nanoparticles which dimensions depend on the biological source of the substrate. In the case of starch they consist of platelet-like nanoparticles. High reinforcing capability was reported resulting from the intrinsic chemical nature of these polymers and from their hierarchical structure. During the last decade, many works have been devoted to mimic biocomposites by blending cellulose whiskers from different sources with polymer matrices.

  15. Biological Properties and Characterization of ASL50 Protein from Aged Allium sativum Bulbs.

    PubMed

    Kumar, Suresh; Jitendra, Kumar; Singh, Kusum; Kapoor, Vaishali; Sinha, Mou; Xess, Immaculata; Das, Satya N; Sharma, Sujata; Singh, Tej P; Dey, Sharmistha

    2015-08-01

    Allium sativum is well known for its medicinal properties. The A. sativum lectin 50 (ASL50, 50 kDa) was isolated from aged A. sativum bulbs and purified by gel filtration chromatography on Sephacryl S-200 column. Agar well diffusion assay were used to evaluate the antimicrobial activity of ASL50 against Candida species and bacteria then minimal inhibitory concentration (MIC) was determined. The lipid A binding to ASL50 was determined by surface plasmon resonance (SPR) technology with varying concentrations. Electron microscopic studies were done to see the mode of action of ASL50 on microbes. It exerted antimicrobial activity against clinical Candida isolates with a MIC of 10-40 μg/ml and clinical Pseudomonas aeruginosa isolates with a MIC of 10-80 μg/ml. The electron microscopic study illustrates that it disrupts the cell membrane of the bacteria and cell wall of fungi. It exhibited antiproliferative activity on oral carcinoma KB cells with an IC50 of 36 μg/ml after treatment for 48 h and induces the apoptosis of cancer cells by inducing 2.5-fold higher caspase enzyme activity than untreated cells. However, it has no cytotoxic effects towards HEK 293 cells as well as human erythrocytes even at higher concentration of ASL50. Biological properties of ASL50 may have its therapeutic significance in aiding infection and cancer treatments.

  16. An analogy between effects of ultra-low doses of biologically active substances on biological objects and properties of spin supercurrents in superfluid 3He-B.

    PubMed

    Boldyreva, Liudmila B

    2011-07-01

    The effects of ultra-low doses (ULDs) of biologically active substances (BASs) (with concentrations of 10(-13)M or lower) on biological objects (BOs), such as cells, organisms, etc., and the properties of spin supercurrents in superfluid (3)He-B are discussed. It is shown that the effects of ULDs of BASs on biologic objects can be specified by the same set of physical characteristics and described by the same mathematical relations as those used for the specification and description of the properties of spin supercurrents between spin structures in superfluid (3)He-B. This is based on the up-to-date physical concepts: 1) the physical vacuum has the properties of superfluid (3)He-B; 2) all quantum entities (hence, the BAS and the BO, which consist of such entities) produce spin structures in the physical vacuum. The photon being a quantum entity, the features of the effects of low-intensity electromagnetic radiation on BOs can be explained using the same approach.

  17. Biologically-initiated rock crust on sandstone: Mechanical and hydraulic properties and resistance to erosion

    NASA Astrophysics Data System (ADS)

    Slavík, Martin; Bruthans, Jiří; Filippi, Michal; Schweigstillová, Jana; Falteisek, Lukáš; Řihošek, Jaroslav

    2017-02-01

    Biocolonization on sandstone surfaces is known to play an important role in rock disintegration, yet it sometimes also aids in the protection of the underlying materials from rapid erosion. There have been few studies comparing the mechanical and/or hydraulic properties of the BIRC (Biologically-Initiated Rock Crust) with its subsurface. As a result, the overall effects of the BIRC are not yet well understood. The objective of the present study was to briefly characterize the BIRC from both the mineralogical and biological points of view, and especially to quantify the effect of the BIRC upon the mechanical and hydraulic properties of friable sandstone. The mineralogical investigation of a well-developed BIRC showed that its surface is enriched in kaolinite and clay- to silt-sized quartz particles. Total organic carbon increases with the age of the BIRC. Based on DNA sequencing and microscopy, the BIRC is formed by various fungi, including components of lichens and green algae. Using the method of drilling resistance, by measuring tensile strength, and based on water jet testing, it was determined that a BIRC is up to 12 times less erodible and has 3-35 times higher tensile strength than the subsurface friable sandstone. Saturated hydraulic conductivity of the studied BIRC is 15-300 times lower than the subsurface, and was measured to also decrease in capillary water absorption (2-33 times). Water-vapor diffusion is not significantly influenced by the presence of the BIRC. The BIRC thus forms a hardened surface which protects the underlying material from rain and flowing water erosion, and considerably modifies the sandstone's hydraulic properties. Exposing the material to calcination (550 °C), and experiments with the enzyme zymolyase indicated that a major contribution to the surface hardening is provided by organic matter. In firmer sandstones, the BIRC may still considerably decrease the rate of weathering, as it is capable of providing cohesion to strongly

  18. Effects of different green manures on soil biological properties and maize yield.

    PubMed

    Tejada, M; Gonzalez, J L; García-Martínez, A M; Parrado, J

    2008-04-01

    The utilization of green manures as alternatives to reduce the use of mineral fertilizers is considered a good agricultural practice. However, the effect of each green manure on soil properties and crop yield depends upon its chemical composition. The main objective of this work was to study the effect of incorporating three green manures originating from residues of Trifolium pratense, L. (TP), Brassica napus, L. (BN), and the mixture of TP+BN at rates of 5384 and 8973 kg C ha(-1), on soil biological properties (soil microbial biomass-C, soil respiration and soil enzymatic activities), nutrition (leaf N, P and K concentration, pigments and soluble carbohydrate concentrations) and yield parameters of maize (Zea mays cv. Tundra) crop for four years on an Typic Xerofluvent located near Sevilla (Guadalquivir Valley, Andalusia, Spain). All green manures had a positive effect on the soil biological properties, plant nutrition an crop yield parameters, although at the end of the experimental period and at the high organic matter rate, the soil microbial biomass and dehydrogenase, urease, beta-glucosidase, phosphatase and arylsulfatase activities increased more significantly in the TP amended soils (79.2%, 92.1%, 93.9%, 99.3%, 87.9% and 96%, respectively) respect to the control soil, followed by TP+BN amended soils (77.3%, 90.9%, 92.8%, 99.1%, 84.4% and 95.7%, respectively) and BN amended soils (76%, 90.1%, 91.7%, 99%, 83.2% and 95.2%, respectively). Since these soil enzymatic activities measured are responsible for important cycles such as C, N, P and S, an increase of leaf N, P an K contents and pigments and soluble carbohydrate contents were highest in TP amended soils, followed by TP+BN and BN treatments. The application of TP in soils at high doses increased the grain protein concentration, number of grains corncob(-1) and crop yield 44.6%, 6.3% and 22.1%, respectively, compared with the control soil, followed by TP+BN treatment (41.7%, 5.7% and 20.8%, respectively

  19. Tree Species Traits Influence Soil Physical, Chemical, and Biological Properties in High Elevation Forests

    PubMed Central

    Ayres, Edward; Steltzer, Heidi; Berg, Sarah; Wallenstein, Matthew D.; Simmons, Breana L.; Wall, Diana H.

    2009-01-01

    Background Previous studies have shown that plants often have species-specific effects on soil properties. In high elevation forests in the Southern Rocky Mountains, North America, areas that are dominated by a single tree species are often adjacent to areas dominated by another tree species. Here, we assessed soil properties beneath adjacent stands of trembling aspen, lodgepole pine, and Engelmann spruce, which are dominant tree species in this region and are distributed widely in North America. We hypothesized that soil properties would differ among stands dominated by different tree species and expected that aspen stands would have higher soil temperatures due to their open structure, which, combined with higher quality litter, would result in increased soil respiration rates, nitrogen availability, and microbial biomass, and differences in soil faunal community composition. Methodology/Principal Findings We assessed soil physical, chemical, and biological properties at four sites where stands of aspen, pine, and spruce occurred in close proximity to one-another in the San Juan Mountains, Colorado. Leaf litter quality differed among the tree species, with the highest nitrogen (N) concentration and lowest lignin∶N in aspen litter. Nitrogen concentration was similar in pine and spruce litter, but lignin∶N was highest in pine litter. Soil temperature and moisture were highest in aspen stands, which, in combination with higher litter quality, probably contributed to faster soil respiration rates from stands of aspen. Soil carbon and N content, ammonium concentration, and microbial biomass did not differ among tree species, but nitrate concentration was highest in aspen soil and lowest in spruce soil. In addition, soil fungal, bacterial, and nematode community composition and rotifer, collembolan, and mesostigmatid mite abundance differed among the tree species, while the total abundance of nematodes, tardigrades, oribatid mites, and prostigmatid mites did not

  20. Mapping the functional properties of soft biological tissues under shear loading

    NASA Astrophysics Data System (ADS)

    Buckley, Mark Raymond

    The structure and composition of articular cartilage and other load-bearing biological tissues are highly complex and heterogeneous. As a result, their functional mechanical properties exhibit clear spatial variations. Unlocking the structure-function relationship in these materials is critical for devising strategies to restore tissue impaired by injury or disease and can provide a template for successful implant design. Here, we describe a tissue deformation imaging stage (TDIS) allowing for simultaneous force measurement and visualization of microscale deformation in soft biological tissues under controlled shear strain. In combination with a fast confocal microscope, the TDIS is used to test the microscale response of articular cartilage to shear loading. To obtain the location-specific shear modulus of this tissue, we employ a high-resolution technique that involves tracking the deformation of a line photobleached into a fluorescently stained sample loaded in the TDIS. We find that the quasi-static and dynamic shear moduli are lowest roughly 100 mum below the articular surface. Here, articular cartilage is highly nonlinear, stiffening under increased shear strain and becoming more compliant under increased compressive strain. Using a simple thought model, we relate these results to structural features of the collagen network in articular cartilage. Furthermore, we demonstrate that the region of maximum compliance is also the primary site of shear energy dissipation in articular cartilage. Our findings suggest that damage to or surgical removal of the surface of this tissue will increase the joint's susceptibility to shear-induced damage. Finally, similar experiments are performed on intervertebral disc and growth plate, demonstrating the versatility of our in-situ strain mapping techniques.

  1. Comparison of Biophysical and Biologic Properties of α-Helical Enantiomeric Antimicrobial Peptides

    PubMed Central

    Chen, Yuxin; Vasil, Adriana I.; Rehaume, Linda; Mant, Colin T.; Burns, Jane L.; Vasil, Michael L.; Hancock, Robert E. W.; Hodges, Robert S.

    2011-01-01

    In our previous study (Chen et al. J Biol Chem 2005, 280:12316–12329), we utilized an α-helical antimicrobial peptide V681 as the framework to study the effects of peptide hydrophobicity, amphipathicity, and helicity on biologic activities where we obtained several V681 analogs with dramatic improvement in peptide therapeutic indices against gram-negative and gram-positive bacteria. In the present study, the d-enantiomers of three peptides – V681, V13AD and V13KL were synthesized to compare biophysical and biologic properties with their enantiomeric isomers. Each d-enantiomer was shown by circular dichroism spectroscopy to be a mirror image of the corresponding l-isomer in benign conditions and in the presence of 50% trifluoroethanol. l- and d-enantiomers exhibited equivalent antimicrobial activities against a diverse group of Pseudomonas aeruginosa clinical isolates, various gram-negative and gram-positive bacteria and a fungus. In addition, l- and d-enantiomeric peptides were equally active in their ability to lyse human red blood cells. The similar activity of l- and d-enantiomeric peptides on prokaryotic or eukaryotic cell membranes suggests that there are no chiral receptors and the cell membrane is the sole target for these peptides. Peptide d-V13KD showed significant improvements in the therapeutic indices compared with the parent peptide V681 by 53-fold against P. aeruginosa strains, 80-fold against gram-negative bacteria, 69-fold against gram-positive bacteria, and 33-fold against Candida albicans. The excellent stability of d-enantiomers to trypsin digestion (no proteolysis by trypsin) compared with the rapid breakdown of the l-enantiomers highlights the advantage of the d-enantiomers and their potential as clinical therapeutics. PMID:16492164

  2. Comparative study of the biological properties of Trypanosoma cruzi I genotypes in a murine experimental model.

    PubMed

    Cruz, Lissa; Vivas, Angie; Montilla, Marleny; Hernández, Carolina; Flórez, Carolina; Parra, Edgar; Ramírez, Juan David

    2015-01-01

    Chagas disease is an endemic zoonosis in Latin America and caused by the parasite Trypanosoma cruzi. This kinetoplastid displays remarkable genetic variability, allowing its classification into six Discrete Typing Units (DTUs) from TcI to TcVI. T. cruzi I presents the broadest geographical distribution in the continent and has been associated to severe forms of cardiomyopathies. Recently, a particular genotype associated to human infections has been reported and named as TcIDOM (previously named TcIa-b). This genotype shows to be clonal and adapted to the domestic cycle but so far no studies have determined the biological properties of domestic (TcIDOM) and sylvatic TcI strains (previously named TcIc-e). Hence, the aim of this study was to untangle the biological features of these genotypes in murine models. We infected ICR-CD1 mice with five TcI strains (two domestic, two sylvatic and one natural mixture) and determined the course of infection during 91 days (acute and chronic phase of the disease) in terms of parasitemia, tissue tropism, immune response (IgG titers) and tissue invasion by means of histopathology studies. Statistically significant differences were observed in terms of parasitemia curves and prepatent period between domestic (TcIDOM) and sylvatic strains. There were no differences in terms of IgG antibodies response across the mice infected with the five strains. Regarding the histopathology, our results indicate that domestic strains present higher parasitemias and low levels of histopathological damage. In contrast, sylvatic strains showed lower parasitemias and high levels of histopathological damage. These results highlight the sympatric and behavioral differences of domestic and sylvatic TcI strains; the clinical and epidemiological implications are herein discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Some properties of methylotrophic bacteria isolated from sewage sludges derived from mechanical and biological sewage treatment plants.

    PubMed

    Durska, Grazyna

    2007-01-01

    The presented studies were carried out to get more information about physiological properties of methylotrophic bacteria selected from sewage sludges derived from mechanical and biological sewage treatment plants. All the isolated bacterial strains belonged to facultative methylotrophs. The majority of them utilized glucose, starch and lipids. Moreover, most of them were also found to possess proteolytic properties and were able to hydrolyze urea but they were incapable of asparagine ammonification.

  4. Path-Integration Computation of the Transport Properties of Polymers Nanoparticles and Complex Biological Structures

    NASA Astrophysics Data System (ADS)

    Douglas, Jack

    2014-03-01

    finite cross-section, DNA, nanoparticles with grafted chain layers and knotted polymers. The path-integration method, which grew up from research in Karl Freed's group, is evidently a powerful tool for computing basic transport properties of complex-shaped objects and should find increasing application in polymer science, nanotechnological applications and biology.

  5. Closed-form equation to estimate the dielectric properties of biological tissues as a function of age.

    PubMed

    Mohammed, Beadaa; Bialkowski, Konstanty; Abbosh, Amin; Mills, Paul C; Bradley, Andrew P

    2017-09-01

    Developing microwave systems for biomedical applications requires accurate dielectric properties of biological tissues for reliable modeling before prototyping and subject testing. Dielectric properties of tissues decrease with age due to the change in their water content, but there are no detailed age-dependent data, especially for young tissue-like newborns, in the literature. In this article, an age-dependent formula to predict the dielectric properties of biological tissues was derived. In the proposed method, the variation of water concentration in each type of tissue as a function of age was used to calculate its relative permittivity and conductivity. The derived formula shows that the concentration of water in each tissue type can be modeled as a negative exponential function of age. The dielectric properties of each tissue type can then be calculated as a function of the dielectric properties of water and dielectric properties of the organ forming the tissue and its water concentration. The derived formula was used to generate the dielectric properties of several types of human tissues at different ages using the dielectric properties of a human adult. Moreover, the formula was validated on pig tissues of different ages. A close agreement was achieved between the calculated and measured data with a maximum difference of only 2%. Bioelectromagnetics. 38:474-481, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  6. Substitutions of strontium in mesoporous calcium silicate and their physicochemical and biological properties.

    PubMed

    Zhu, Yufang; Zhu, Min; He, Xing; Zhang, Jianhua; Tao, Cuilian

    2013-05-01

    Calcium silicate (Ca-Si) based bioceramics have been regarded as a potential bioactive materials for bone tissue regeneration. In this study, we have successfully prepared ordered mesoporous strontium (Sr)-substituted CaSiO3 (Sr-CaSiO3) materials by using a triblock copolymer (P123) as a structure-directing agent. The microstructure and porosity of mesoporous Sr-CaSiO3 materials were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and the N2 adsorption-desorption technique. The substitution of Sr for Ca in mesoporous CaSiO3 did not change the mesoporous structure, but the surface area and pore volume decreased with increasing Sr substitution. The effects of the Sr substitution on the physiochemical and biological properties of mesoporous CaSiO3 materials were evaluated by the ion dissolution, apatite-forming ability, proliferation and alkaline phosphatase (ALP) activity of osteoblast-like MC3T3-E1 cells. The results showed that the increasing Sr substitution decreased the dissolution rate of Ca and Si ions from mesoporous CaSiO3 materials and enhanced the ability to stabilize the pH environment. Mesoporous Sr-CaSiO3 materials have a similar apatite-forming ability to mesoporous CaSiO3 material, and stimulated the proliferation and ALP activity of MC3T3-E1 cells. Furthermore, using gentamicin as a model drug, mesoporous Sr-CaSiO3 materials exhibited a sustained drug release property which could be used in local drug delivery therapy. Furthermore, the drug release rate decreased to some extent with increasing Sr substitution in mesoporous CaSiO3 materials. Therefore, mesoporous Sr-CaSiO3 materials have more potential for application in bone tissue regeneration. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  7. Potential of Magnetic Nanofiber Scaffolds with Mechanical and Biological Properties Applicable for Bone Regeneration

    PubMed Central

    Singh, Rajendra K.; Patel, Kapil D.; Lee, Jae Ho; Lee, Eun-Jung; Kim, Joong-Hyun; Kim, Tae-Hyun; Kim, Hae-Won

    2014-01-01

    Magnetic nanofibrous scaffolds of poly(caprolactone) (PCL) incorporating magnetic nanoparticles (MNP) were produced, and their effects on physico-chemical, mechanical and biological properties were extensively addressed to find efficacy for bone regeneration purpose. MNPs 12 nm in diameter were citrated and evenly distributed in PCL solutions up to 20% and then were electrospun into nonwoven nanofibrous webs. Incorporation of MNPs greatly improved the hydrophilicity of the nanofibers. Tensile mechanical properties of the nanofibers (tensile strength, yield strength, elastic modulus and elongation) were significantly enhanced with the addition of MNPs up to 15%. In particular, the tensile strength increase was as high as ∼25 MPa at 15% MNPs vs. ∼10 MPa in pure PCL. PCL-MNP nanofibers exhibited magnetic behaviors, with a high saturation point and hysteresis loop area, which increased gradually with MNP content. The incorporation of MNPs substantially increased the degradation of the nanofibers, with a weight loss of ∼20% in pure PCL, ∼45% in 10% MNPs and ∼60% in 20% MNPs. Apatite forming ability of the nanofibers tested in vitro in simulated body fluid confirmed the substantial improvement gained by the addition of MNPs. Osteoblastic cells favored the MNPs-incorporated nanofibers with significantly improved initial cell adhesion and subsequent penetration through the nanofibers, compared to pure PCL. Alkaline phosphatase activity and expression of genes associated with bone (collagen I, osteopontin and bone sialoprotein) were significantly up-regulated in cells cultured on PCL-MNP nanofibers than those on pure PCL. PCL-MNP nanofibers subcutaneously implanted in rats exhibited minimal adverse tissue reactions, while inducing substantial neoblood vessel formation, which however, greatly limited in pure PCL. In vivo study in radial segmental defects also signified the bone regeneration ability of the PCL-MNP nanofibrous scaffolds. The magnetic, bone

  8. Biological properties of carotenoids extracted from Halobacterium halobium isolated from a Tunisian solar saltern

    PubMed Central

    2013-01-01

    Background Bioactive molecules have received increasing attention due to their nutraceutical attributes and anticancer, antioxidant, antiproliferative and apoptosis-inducing properties. This study aimed to investigate the biological properties of carotenoids extracted from Archaea. Methods Halophilic Archaea strains were isolated from the brine of a local crystallizer pond (TS7) of a solar saltern at Sfax, Tunisia. The most carotenoid-producing strain (M8) was investigated on heptoma cell line (HepG2), and its viability was assessed by the MTT-test. The cells were incubated with different sub-lethal extract rates, with carotenoid concentrations ranging from 0.2 to 1.5 μM. Antioxidant activity was evaluated through exposing the cells to sub-lethal extract concentrations for 24 hours and then to oxidative stress induced by 60 μM arachidonic acid and 50 μM H2O2. Results Compared to non-treated cells, bacterial carotenoid extracts inhibited HepG2 cell viability (50%). A time and dose effect was observed, with cell viability undergoing a significant (P < 0.05) decrease with extract concentration. After exposure to oxidative stress, control cells underwent a significant (P < 0.05) decrease in viability as compared to the non-treated cells. Conclusions The bacterial extracts under investigation were noted to exhibit the strongest free radical scavenging activity with high carotenoid concentrations. The carotenoid extract also showed significant antiproliferative activity against HepG2 human cancer cell lines. PMID:24090008

  9. Titanium dioxide nanotubes addition to self-adhesive resin cement: Effect on physical and biological properties.

    PubMed

    Ramos-Tonello, Carla M; Lisboa-Filho, Paulo N; Arruda, Larisa B; Tokuhara, Cintia K; Oliveira, Rodrigo C; Furuse, Adilson Y; Rubo, José H; Borges, Ana Flávia S

    2017-07-01

    This study has investigated the influence of Titanium dioxide nanotubes (TiO2-nt) addition to self-adhesive resin cement on the degree of conversion, water sorption, and water solubility, mechanical and biological properties. A commercially available auto-adhesive resin cement (RelyX U200™, 3M ESPE) was reinforced with varying amounts of nanotubes (0.3, 0.6, 0.9wt%) and evaluated at different curing modes (self- and dual cure). The DC in different times (3, 6, 9, 12 and 15min), water sorption (Ws) and solubility (Sl), 3-point flexural strength (σf), elastic modulus (E), Knoop microhardness (H) and viability of NIH/3T3 fibroblasts were performed to characterize the resin cement. Reinforced self-adhesive resin cement, regardless of concentration, increased the DC for the self- and dual-curing modes at all times studied. The concentration of the TiO2-nt and the curing mode did not influence the Ws and Sl. Regarding σf, concentrations of both 0.3 and 0.9wt% for self-curing mode resulted in data similar to that of dual-curing unreinforced cement. The E increased with the addition of 0.9wt% for self-cure mode and H increased with 0.6 and 0.9wt% for both curing modes. Cytotoxicity assays revealed that reinforced cements were biocompatible. TiO2-nt reinforced self-adhesive resin cement are promising materials for use in indirect dental restorations. Taken together, self-adhesive resin cement reinforced with TiO2-nt exhibited physicochemical and mechanical properties superior to those of unreinforced cements, without compromising their cellular viability. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  10. Fab-based bispecific antibody formats with robust biophysical properties and biological activity.

    PubMed

    Wu, Xiufeng; Sereno, Arlene J; Huang, Flora; Lewis, Steven M; Lieu, Ricky L; Weldon, Caroline; Torres, Carina; Fine, Cody; Batt, Micheal A; Fitchett, Jonathan R; Glasebrook, Andrew L; Kuhlman, Brian; Demarest, Stephen J

    2015-01-01

    A myriad of innovative bispecific antibody (BsAb) platforms have been reported. Most require significant protein engineering to be viable from a development and manufacturing perspective. Single-chain variable fragments (scFvs) and diabodies that consist only of antibody variable domains have been used as building blocks for making BsAbs for decades. The drawback with Fv-only moieties is that they lack the native-like interactions with CH1/CL domains that make antibody Fab regions stable and soluble. Here, we utilize a redesigned Fab interface to explore 2 novel Fab-based BsAbs platforms. The redesigned Fab interface designs limit heavy and light chain mixing when 2 Fabs are co-expressed simultaneously, thus allowing the use of 2 different Fabs within a BsAb construct without the requirement of one or more scFvs. We describe the stability and activity of a HER2×HER2 IgG-Fab BsAb, and compare its biophysical and activity properties with those of an IgG-scFv that utilizes the variable domains of the same parental antibodies. We also generated an EGFR × CD3 tandem Fab protein with a similar format to a tandem scFv (otherwise known as a bispecific T cell engager or BiTE). We show that the Fab-based BsAbs have superior biophysical properties compared to the scFv-based BsAbs. Additionally, the Fab-based BsAbs do not simply recapitulate the activity of their scFv counterparts, but are shown to possess unique biological activity.

  11. Biological properties of cardiac mesenchymal stem cells in rats with diabetic cardiomyopathy.

    PubMed

    de Paula, Diógenes Rodrigo Maronezzi; Capuano, Vanessa; Filho, Daniel Mendes; Carneiro, Anna Cecília Dias Maciel; de Oliveira Crema, Virgínia; de Oliveira, Lucas Felipe; Rodrigues, Aldo Rogélis Aquiles; Montano, Nicola; da Silva, Valdo José Dias

    2017-11-01

    Cardiomyopathy is a major outcome in patients with diabetes mellitus (DM) and contributes to the high morbidity/mortality observed in this disease. To evaluate several biological properties of cardiac mesenchymal stem cells (cMSCs) in a rat model of streptozotocin-induced DM with concomitant diabetic cardiomyopathy. After 10weeks of DM induction, diabetic and control rats were assessed using ECG and ventricular hemodynamics monitoring. Then, the hearts were excised and processed for histology and for extracting non-cardiomyocytic cells. A pool of these cells was plated for a colony forming units-fibroblasts (CFU-F) assay in order to estimate the number of cMSCs. The remaining cells were expanded to assess their proliferation rate as well as their osteogenic and adipogenic differentiation ability. DM rats presented intense hyperglycemia and changes in ECG, LV hemodynamic, cardiac mass index and fibrosis, indicating presence of DCM. The CFU-F assay revealed a higher number of cardiac CFU-Fs in DM rats (10.4±1.1CFU-F/10(5) total cells versus 7.6±0.7CFU-F/10(5) total cells in control rats, p<0.05), which was associated with a significantly higher proliferative rate of cMSCs in DM rats. In contrast, cMSCs from DM rats presented a lower capacity to differentiate into both osteogenic (20.8±4.2% versus 10.1±1.0% in control rats, p<0.05) and adipogenic lineages (4.6±1.0% versus 1.3±0.5% in control rats, p<0.05). The findings suggest, for the first time, that in chronic DM rats with overt DCM, cMSCs increase in number and exhibit changes in several functional properties, which could be implicated in the pathogenesis of diabetic cardiomyopathy. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Improved algorithm for estimating optical properties of food and biological materials using spatially-resolved diffuse reflectance

    USDA-ARS?s Scientific Manuscript database

    In this research, the inverse algorithm for estimating optical properties of food and biological materials from spatially-resolved diffuse reflectance was optimized in terms of data smoothing, normalization and spatial region of reflectance profile for curve fitting. Monte Carlo simulation was used ...

  13. CARBON LOSS AND OPTICAL PROPERTY CHANGES DURING LONG-TERM PHOTOCHEMICAL AND BIOLOGICAL DEGRADATION OF ESTUARINE DISSOLVED ORGANIC MATTER

    EPA Science Inventory

    Terrestrially derived dissolved organic matter (DOM) impacts the optical properties of coastal seawater and affects carbon cycling on a global scale. We studied sequential long-term photochemical and biological degradation of estuarine dissolved organic matter from the
    Satilla...

  14. CARBON LOSS AND OPTICAL PROPERTY CHANGES DURING LONG-TERM PHOTOCHEMICAL AND BIOLOGICAL DEGRADATION OF ESTUARINE DISSOLVED ORGANIC MATTER

    EPA Science Inventory

    Terrestrially derived dissolved organic matter (DOM) impacts the optical properties of coastal seawater and affects carbon cycling on a global scale. We studied sequential long-term photochemical and biological degradation of estuarine dissolved organic matter from the
    Satilla...

  15. Some biologically active oxovanadium(IV) complexes of triazole derived Schiff bases: their synthesis, characterization and biological properties.

    PubMed

    Chohan, Zahid H; Sumrra, Sajjad H

    2010-10-01

    A series of biologically active oxovanadium(IV) complexes of triazole derived Schiff bases L(1)-L(5) have been synthesized and characterized by their physical, analytical, and spectral data. The synthesized ligands potentially act as bidentate, in which the oxygen of furfural and nitrogen of azomethine coordinate with the oxovanadium atom to give a stoichiometry of vanadyl complexes 1:2 (M:L) in a square-pyramidal geometry. In vitro antibacterial and antifungal activities on different species of pathogenic bacteria (E. coli, S. flexneri, P. aeruginosa, S. typhi, S. aureus, and B. subtilis) and fungi (T. longifusus, C. albicans, A. flavus, M. canis, F. solani, and C. glabrata) have been studied. All compounds showed moderate to significant antibacterial activity against one or more bacterial strains and good antifungal activity against most of the fungal strains. The brine shrimp bioassay was also carried out to check the cytotoxicity of coordinated and uncoordinated synthesized compounds.

  16. LASER METHODS IN BIOLOGY: Optical anisotropy of fibrous biological tissues: analysis of the influence of structural properties

    NASA Astrophysics Data System (ADS)

    Zimnyakov, D. A.; Sinichkin, Yu P.; Ushakova, O. V.

    2007-08-01

    The results of theoretical analysis of the optical anisotropy of multiply scattering fibrillar biological tissues based on the model of an effective anisotropic medium are compared with the experimental in vivo birefringence data for the rat derma obtained earlier in spectral polarisation measurements of rat skin samples in the visible region. The disordered system of parallel dielectric cylinders embedded into an isotropic dielectric medium was considered as a model medium. Simulations were performed taking into account the influence of a partial mutual disordering of the bundles of collagen and elastin fibres in derma on birefringence in samples. The theoretical optical anisotropy averaged over the spectral interval 550-650 nm for the model medium with parameters corresponding to the structural parameters of derma is in good agreement with the results of spectral polarisation measurements of skin samples in the corresponding wavelength range.

  17. Comparison of biological properties of St. Louis encephalitis and Rio bravo viruses.

    PubMed

    Hendricks, D A; Hardy, J L; Reeves, W C

    1983-05-01

    St. Louis encephalitis (SLE) virus, an arbovirus, and Rio Bravo (RB) virus, a non-arthropod-borne virus, are flaviviruses which cross-react in neutralization tests. Several of their biological properties were compared. Viral growth curves revealed that greater than 99% of infectious SLE (Parton) virus remained cell-associated in Vero cells but was released slowly into the medium of infected BHK-21 cells. In contrast, RB (M-64) virus was released upon maturation into the fluids of Vero and BHK-21 cell cultures. Fortyfold more SLE virus than RB virus adsorbed to monolayer cultures of Aedes dorsalis cells. SLE but not RB virus replicated and reached high titers (10(8) pfu/ml) in Ae. dorsalis cell cultures maintained in media which were expected to enhance recovery of RB virus. Further, SLE but not RB virus replicated in cultured bat epithelial cells and primary duck embryo cells incubated at 42 degrees C. Clearly, the prototype strains of RB and SLE viruses are distinct viruses. Both the classification of RB virus in the genus flavivirus and the antigenic relationship between RB and SLE viruses require further clarification.

  18. Biological properties of a crude venom extract from the greater weever fish Trachinus draco.

    PubMed

    Chhatwal, I; Dreyer, F

    1992-01-01

    Crude venom of the greater weever fish, Trachinus draco was analyzed to assess its toxicity, stability and biological properties. The best yield of venom was obtained by extraction in physiological saline of the whole venom apparatus of the fish which were shock-frozen and stored at -70 degrees C. This extract had a mouse i.v. minimum lethal dose of 1.8 micrograms protein per gram mouse and a total of 61,000 minimum lethal doses were obtained from venom apparatus of one fish. The lethal activity was unstable at room temperature especially at lower protein concentrations. Stability was achieved either by storing the extract at -70 degrees C or by precipitation with ammonium sulfate at 50% saturation. Toxicity of the crude venom was abolished by trypsin treatment. The crude venom did not possess any proteolytic or histamine-releasing activities. The venom caused an outflow of tetraphenylphosphonium from preloaded rat brain particles in a concentration-dependent manner. Like toxicity, this effect was also abolished by trypsin treatment or by keeping the venom at higher temperatures. The crude venom also possessed hemolytic activity with an EC50 for rabbit erythrocytes of 75 ng/ml venom protein. The hemolytic activity was also sensitive to heat and proteolytic treatment. Rabbit erythrocytes were most sensitive to venom followed by rat erythrocytes. Mouse and cattle erythrocytes were only slightly sensitive, whereas human, chicken and guinea pig erythrocytes were totally resistant.

  19. Design, synthesis and biological activity of a novel Rutin analogue with improved lipid soluble properties.

    PubMed

    Baldisserotto, Anna; Vertuani, Silvia; Bino, Alessia; De Lucia, Daniela; Lampronti, Ilaria; Milani, Roberta; Gambari, Roberto; Manfredini, Stefano

    2015-01-01

    Recent interest in flavonoids has increased greatly due to their biological and pharmacological activities. Flavonoids, consist of a large group of low molecular weight polyphenolic substances, naturally occurring in fruits, vegetables, tea, and wine, and are an integral part of the human diet. Rutin is a common dietary flavonoid that is widely consumed worldwide from plant-derived beverages and foods as traditional and folk medicine remedy as well. Rutin exhibit important pharmacological activities, including anti-oxidation, anti-inflammation, anti-diabetic, anti-adipogenic, neuroprotective and hormone therapy. Here, we present the synthesis, antimicrobial, antiproliferative and pro-apoptotic effect on human leukemic K562 cells of compound R2, a new semi-synthetic derivative of Rutin as compared to Rutin itself. The new derivative was also included in finished topical formulations to evaluate a potential application to the dermatology field in view of the antioxidant/antimicrobial/antiinflammatory properties. Stability studies were performed by HPLC; PCL assay and ORAC tests were used to determine the antioxidant activity. R2 presented an antioxidant activity very close to that of the parent Rutin while bearing much better lipophilic character. Regarding antiproliferative effects on the human K562 cell line, R2 was found to be more effective than parent Rutin. Preliminary experiments demonstrated that R2 inhibits NF-kB activity and promotes cellular apoptosis.

  20. Physical properties and biological activities of hesperetin and naringenin in complex with methylated β-cyclodextrin

    PubMed Central

    Sangpheak, Waratchada; Kicuntod, Jintawee; Schuster, Roswitha; Rungrotmongkol, Thanyada; Wolschann, Peter; Kungwan, Nawee; Viernstein, Helmut

    2015-01-01

    Summary The aim of this work is to improve physical properties and biological activities of the two flavanones hesperetin and naringenin by complexation with β-cyclodextrin (β-CD) and its methylated derivatives (2,6-di-O-methyl-β-cyclodextrin, DM-β-CD and randomly methylated-β-CD, RAMEB). The free energies of inclusion complexes between hesperetin with cyclodextrins (β-CD and DM-β-CD) were theoretically investigated by molecular dynamics simulation. The free energy values obtained suggested a more stable inclusion complex with DM-β-CD. The vdW force is the main guest–host interaction when hesperetin binds with CDs. The phase solubility diagram showed the formation of a soluble complex of AL type, with higher increase in solubility and stability when hesperetin and naringenin were complexed with RAMEB. Solid complexes were prepared by freeze-drying, and the data from differential scanning calorimetry (DSC) confirmed the formation of inclusion complexes. The data obtained by the dissolution method showed that complexation with RAMEB resulted in a better release of both flavanones to aqueous solution. The flavanones-β-CD/DM-β-CD complexes demonstrated a similar or a slight increase in anti-inflammatory activity and cytotoxicity towards three different cancer cell lines. The overall results suggested that solubilities and bioactivities of both flavanones were increased by complexation with methylated β-CDs. PMID:26877798

  1. Dielectric properties of biological tissues in which cells are connected by communicating junctions

    NASA Astrophysics Data System (ADS)

    Asami, Koji

    2007-06-01

    The frequency dependence of the complex permittivity of biological tissues has been simulated using a simple model that is a cubic array of spherical cells in a parallel plate capacitor. The cells are connected by two types of communicating junctions: one is a membrane-lined channel for plasmodesmata in plant tissues, and the other is a conducting patch of adjoining plasma membranes for gap junctions in animal tissues. Both junctions provided similar effects on the dielectric properties of the tissue model. The model without junction showed a dielectric relaxation (called β-dispersion) that was expected from an interfacial polarization theory for a concentrated suspension of spherical cells. The dielectric relaxation was the same as that of the model in which neighbouring cells were connected by junctions perpendicular to the applied electric field. When neighbouring cells were connected by junctions parallel to the applied electric field or in all directions, a dielectric relaxation appeared at a lower frequency side in addition to the β-dispersion, corresponding to the so called α-dispersion. When junctions were randomly introduced at varied probabilities Pj, the low-frequency (LF) relaxation curve became broader, especially at Pj of 0.2-0.5, and its intensity was proportional to Pj up to 0.7. The intensity and the characteristic frequency of the LF relaxation both decreased with decreasing junction conductance. The simulations indicate that communicating junctions are important for understanding the LF dielectric relaxation in tissues.

  2. Preparation and biological properties of PLLA/beta-TCP composites reinforced by chitosan fibers.

    PubMed

    Wang, Jing; Qu, Lijie; Meng, Xiangcai; Gao, Jing; Li, Hongbo; Wen, Guangwu

    2008-06-01

    Chitosan fibers were introduced into a poly(L-lactic acid)/beta-tricalcium phosphate (PLLA/beta-TCP) matrix as reinforcement to prepare scaffold materials for bone tissue engineering with adequate initial strength and a feasible degradation rate. The structure and morphology of the composites were observed by a scanning electron microscope (SEM). The porosity of the composites was tested by Archimedes' method. The mechanical property of the composites was measured. Simulated body fluid (SBF) experiments were conducted to assess the bioactivity of the composites. The chemical components of resultants on surfaces were analyzed by Fourier transform infrared spectroscopy (FTIR). The influence of the addition of chitosan fibers on the pH value, mass loss rate and structure of samples during immersion was also discussed. The results show that the initial compressive strength reaches 16.07 MPa when the composites prepared have a porosity of 36%. With the degradation of chitosan fibers, an interconnected structure is earlier formed in situ throughout the scaffolds, which is favorable for new bone ingrowth. The compressive strength of the composite decreases flatly and still maintains at 5.28 MPa after immersion in SBF for 24 days. Meanwhile, the formation of a layer of bone-like apatites on the surfaces of the samples indicates good biological activity. It is concluded that the composites have a promising prospect as bone tissue engineering materials.

  3. Biological properties of purified recombinant HCV particles with an epitope-tagged envelope

    SciTech Connect

    Takahashi, Hitoshi; Akazawa, Daisuke; Kato, Takanobu; Date, Tomoko; Shirakura, Masayuki; Nakamura, Noriko; Mochizuki, Hidenori; Tanaka-Kaneko, Keiko; Sata, Tetsutaro; Tanaka, Yasuhito; Mizokami, Masashi; Suzuki, Tetsuro; Wakita, Takaji

    2010-05-14

    To establish a simple system for purification of recombinant infectious hepatitis C virus (HCV) particles, we designed a chimeric J6/JFH-1 virus with a FLAG (FL)-epitope-tagged sequence at the N-terminal region of the E2 hypervariable region-1 (HVR1) gene (J6/JFH-1/1FL). We found that introduction of an adaptive mutation at the potential N-glycosylation site (E2N151K) leads to efficient production of the chimeric virus. This finding suggests the involvement of glycosylation at Asn within the envelope protein(s) in HCV morphogenesis. To further analyze the biological properties of the purified recombinant HCV particles, we developed a strategy for large-scale production and purification of recombinant J6/JFH-1/1FL/E2N151K. Infectious particles were purified from the culture medium of J6/JFH-1/1FL/E2N151K-infected Huh-7 cells using anti-FLAG affinity chromatography in combination with ultrafiltration. Electron microscopy of the purified particles using negative staining showed spherical particle structures with a diameter of 40-60 nm and spike-like projections. Purified HCV particle-immunization induced both an anti-E2 and an anti-FLAG antibody response in immunized mice. This strategy may contribute to future detailed analysis of HCV particle structure and to HCV vaccine development.

  4. Biological and chemical-physical properties of root-end filling materials: A comparative study.

    PubMed

    Ceci, Matteo; Beltrami, Riccardo; Chiesa, Marco; Colombo, Marco; Poggio, Claudio

    2015-01-01

    The purpose of the study is to evaluate and compare the biological and chemical-physical properties of four different root-end filling materials. Cytotoxicity towards murine odontoblasts cells (MDPC-23) was evaluated using the Transwell insert methodology by Alamar blue test. Streptococcus salivarius, S. sanguis, and S. mutans strains were selected to evaluate the antimicrobial activity by agar disc diffusion test. Solubility was determined after 24 h and 2 months. pH values were measured after 3 and 24 h. To evaluate radiopacity, all materials were scanned on a GE Healthcare Lunar Prodigy. Excellent percentage of vitality were obtained by mineral trioxide aggregate (MTA)-based materials and Biodentine. MTA-Angelus, ProRoot MTA, and Intermediate Restorative Material (IRM) showed the highest values for the inhibition zones when tested for S. mutans, while Biodentine showed the largest inhibition zone when tested for S. sanguis. All the materials fulfilled the requirements of the International Standard 6876, demonstrating low solubility with a weight loss of less than 3%. No significant reduction in pH value was demonstrated after 24 h. ProRoot MTA and MTA-Angelus showed the highest values of radiographic density. The differences showed by the root-end filling materials tested do not cover completely the ideal clinical requests.

  5. Effect of heparin on the biological properties and molecular signature of human mesenchymal stem cells

    PubMed Central

    Ling, Ling; Camilleri, Emily T.; Helledie, Torben; Samsonraj, Rebekah M.; Titmarsh, Drew M.; Chua, Ren Jie; Dreesen, Oliver; Dombrowski, Christian; Rider, David A.; Galindo, Mario; Lee, Ian; Hong, Wanjin; Hui, James H.; Nurcombe, Victor; van Wijnen, Andre J.; Cool, Simon M.

    2017-01-01

    Chronic use of heparin as an anti-coagulant for the treatment of thrombosis or embolism invokes many adverse systemic events including thrombocytopenia, vascular reactions and osteoporosis. Here, we addressed whether adverse effects might also be directed to mesenchymal stem cells that reside in the bone marrow compartment. Harvested human bone marrow-derived mesenchymal stem cells (hMSCs) were exposed to varying doses of heparin and their responses profiled. At low doses (<200 ng/ml), serial passaging with heparin exerted a variable effect on hMSC proliferation and multipotentiality across multiple donors, while at higher doses (≥100 µg/ml), heparin supplementation inhibited cell growth and increased both senescence and cell size. Gene expression profiling using cDNA arrays and RNA-seq analysis revealed pleiotropic effects of low-dose heparin on signaling pathways essential to hMSC growth and differentiation (including the TGFβ/BMP superfamily, FGFs, and Wnts). Cells serially passaged in low-dose heparin possess a donor-dependent gene signature that reflects their altered phenotype. Our data indicate that heparin supplementation during the culturing of hMSCs can alter their biological properties, even at low doses. This warrants caution in the application of heparin as a culture supplement for the ex vivo expansion of hMSCs. It also highlights the need for careful evaluation of the bone marrow compartment in patients receiving chronic heparin treatment. PMID:26484394

  6. Isolation, Characterization and Biological Properties of Membrane Vesicles Produced by the Swine Pathogen Streptococcus suis

    PubMed Central

    Haas, Bruno; Grenier, Daniel

    2015-01-01

    Streptococcus suis, more particularly serotype 2, is a major swine pathogen and an emerging zoonotic agent worldwide that mainly causes meningitis, septicemia, endocarditis, and pneumonia. Although several potential virulence factors produced by S. suis have been identified in the last decade, the pathogenesis of S. suis infections is still not fully understood. In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material. A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors. Biological assays confirmed that S. suis MVs possess active subtilisin-like protease (SspA) and DNase (SsnA). S. suis MVs degraded neutrophil extracellular traps, a property that may contribute to the ability of the bacterium to escape the host defense response. MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier. The present study brought evidence that S. suis MVs may play a role as a virulence factor in the pathogenesis of S. suis infections, and given their composition be an excellent candidate for vaccine development. PMID:26110524

  7. The impact of antibiotics (benzylpenicillin, and nystatin) on the biological properties of ordinary chernozems

    NASA Astrophysics Data System (ADS)

    Akimenko, Yu. V.; Kazeev, K. Sh.; Kolesnikov, S. I.

    2014-09-01

    In recent years, the input of antibiotics into soils has sharply increased. We studied the impact antibiotics (benzylpenicillin, pharmasin, and nystatin) at different concentrations (100 and 600 mg/kg) on population densities of microorganisms and enzymatic activity of ordinary chernozems in model experiments. The applied doses of antibiotics had definite suppressing effects on population densities of microorganisms (up to 30-70% of the control) and on the soil enzymatic activity (20-70% of the control). Correlation analysis showed close correlation between the concentrations of antibiotics and the population densities of soil microorganisms ( r = -0.68-0.86). Amylolytic bacteria had the highest resistance to the antibiotics, whereas ammonifying bacteria had the lowest resistance. Among the studied enzymes belonging to oxidoreductases and hydrolases, catalase and phosphatase had the highest and the lowest resistance to the antibiotics, respectively. The effect of antibiotics on the biological properties of the chernozem lasted for a long time. The studied parameters were not completely recovered in 120 days.

  8. The Mechanism and Properties of Electron Transfer in the Biological Organism

    NASA Astrophysics Data System (ADS)

    Pang, Xiao-Feng

    2013-08-01

    The mechanism and properties of electron transfer along protein molecules at finite temperature T ≠ 0 in the life systems are studied using nonlinear theory of bio-energy transport and Green function method, in which the electrons are transferred from donors to acceptors in virtue of the supersound soliton excited by the energy released in ATP hydrolysis. The electron transfer is, in essence, a process of oxidation-reduction reaction. In this study we first give the Hamiltonian and wavefunction of the system and find out the soliton solution of the dynamical equation in the protein molecules with finite temperature, and obtain the dynamical coefficient of the electron transfer. The results show that the speed of the electron transfer is related to the velocity of motion of the soliton, distribution of electrons in the donor and acceptor as well as the interaction strength among them. We finally concluded the changed rule of electric current, arising from the electron transfer, with increasing time. These results are useful in molecular and chemical biology.

  9. Effect of heparin on the biological properties and molecular signature of human mesenchymal stem cells.

    PubMed

    Ling, Ling; Camilleri, Emily T; Helledie, Torben; Samsonraj, Rebekah M; Titmarsh, Drew M; Chua, Ren Jie; Dreesen, Oliver; Dombrowski, Christian; Rider, David A; Galindo, Mario; Lee, Ian; Hong, Wanjin; Hui, James H; Nurcombe, Victor; van Wijnen, Andre J; Cool, Simon M

    2016-01-15

    Chronic use of heparin as an anti-coagulant for the treatment of thrombosis or embolism invokes many adverse systemic events including thrombocytopenia, vascular reactions and osteoporosis. Here, we addressed whether adverse effects might also be directed to mesenchymal stem cells that reside in the bone marrow compartment. Harvested human bone marrow-derived mesenchymal stem cells (hMSCs) were exposed to varying doses of heparin and their responses profiled. At low doses (<200 ng/ml), serial passaging with heparin exerted a variable effect on hMSC proliferation and multipotentiality across multiple donors, while at higher doses (≥ 100 μg/ml), heparin supplementation inhibited cell growth and increased both senescence and cell size. Gene expression profiling using cDNA arrays and RNA-seq analysis revealed pleiotropic effects of low-dose heparin on signaling pathways essential to hMSC growth and differentiation (including the TGFβ/BMP superfamily, FGFs, and Wnts). Cells serially passaged in low-dose heparin possess a donor-dependent gene signature that reflects their altered phenotype. Our data indicate that heparin supplementation during the culturing of hMSCs can alter their biological properties, even at low doses. This warrants caution in the application of heparin as a culture supplement for the ex vivo expansion of hMSCs. It also highlights the need for careful evaluation of the bone marrow compartment in patients receiving chronic heparin treatment.

  10. Near infrared fluorescence quenching properties of copper (II) ions for potential applications in biological imaging

    NASA Astrophysics Data System (ADS)

    Maji, Dolonchampa; Zhou, Mingzhou; Sarder, Pinaki; Achilefu, Samuel

    2014-03-01

    Fluorescence quenching properties of copper(II) ions have been used for designing Cu(II) sensitive fluorescent molecular probes. In this paper, we demonstrate that static quenching plays a key role in free Cu(II)-mediated fluorescence quenching of a near infrared (NIR) fluorescent dye cypate. The Stern-Volmer quenching constant was calculated to be KSV = 970,000 M-1 in 25 mM MES buffer, pH 6.5 at room temperature. We synthesized LS835, a compound containing cypate attached covalently to chelated Cu(II) to study fluorescence quenching by chelated Cu(II). The fluorescence quenching mechanism of chelated Cu(II) is predominantly dynamic or collisional quenching. The quenching efficiency of chelated Cu(II) was calculated to be 58% ± 6% in dimethylsulfoxide at room temperature. Future work will involve further characterization of the mechanism of NIR fluorescence quenching by Cu(II) and testing its reversibility for potential applications in designing fluorophore-quencher based molecular probes for biological imaging.

  11. Structural, physicochemical and biological properties of spray-dried wine powders.

    PubMed

    Wilkowska, Agnieszka; Czyżowska, Agata; Ambroziak, Wojciech; Adamiec, Janusz

    2017-08-01

    Different fruit wines, chokeberry, blackcurrant and blueberry, were spray-dried using hydroxypropyl-β-cyclodextrin (HP-β-CD) and inulin (IN). The structural, physicochemical, and biological properties of the spray-dried wine powders were studied over 12months of storage in darkness at 8°C. Identification and quantification of single phenolic compounds before and after storage revealed that HP-β-CD had a positive effect on anthocyanin retention during storage for all microcapsules tested. Similar decreases in anthocyanin were found for blackcurrant and chokeberry powders, ranging from 7.3 to 8.9% with HP-β-CD and 12.3 to 12.5% with IN. Levels of anthocyanin losses in blueberry wine microcapsules were much greater: 19.9% (HP-β-CD) and 22.7% (IN). The high antiradical activities of blackcurrant and chokeberry wine microcapsules were stable and remained unchanged during storage. All wine microcapsules revealed significant activity against medically important bacterial strains. The HP-β-CD samples showed generally higher activity against the test microorganisms compared to IN microcapsules, especially at concentrations of 100mg/mL. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Biological and chemical-physical properties of root-end filling materials: A comparative study

    PubMed Central

    Ceci, Matteo; Beltrami, Riccardo; Chiesa, Marco; Colombo, Marco; Poggio, Claudio

    2015-01-01

    Aim: The purpose of the study is to evaluate and compare the biological and chemical-physical properties of four different root-end filling materials. Materials and Methods: Cytotoxicity towards murine odontoblasts cells (MDPC-23) was evaluated using the Transwell insert methodology by Alamar blue test. Streptococcus salivarius, S. sanguis, and S. mutans strains were selected to evaluate the antimicrobial activity by agar disc diffusion test. Solubility was determined after 24 h and 2 months. pH values were measured after 3 and 24 h. To evaluate radiopacity, all materials were scanned on a GE Healthcare Lunar Prodigy. Results: Excellent percentage of vitality were obtained by mineral trioxide aggregate (MTA)-based materials and Biodentine. MTA-Angelus, ProRoot MTA, and Intermediate Restorative Material (IRM) showed the highest values for the inhibition zones when tested for S. mutans, while Biodentine showed the largest inhibition zone when tested for S. sanguis. All the materials fulfilled the requirements of the International Standard 6876, demonstrating low solubility with a weight loss of less than 3%. No significant reduction in pH value was demonstrated after 24 h. ProRoot MTA and MTA-Angelus showed the highest values of radiographic density. Conclusions: The differences showed by the root-end filling materials tested do not cover completely the ideal clinical requests. PMID:25829684

  13. Porous Tantalum Structures for Bone Implants: Fabrication, Mechanical and In vitro Biological Properties

    PubMed Central

    Balla, Vamsi Krishna; Bodhak, Subhadip; Bose, Susmita; Bandyopadhyay, Amit

    2010-01-01

    Relatively high cost of manufacturing and inability to produce modular all tantalum implants has limited its widespread acceptance, in spite of its excellent in vitro and in vivo biocompatibility. In this article, we report how to process Ta to create net shape porous structures with varying porosity using Laser Engineered Net Shaping (LENS™) for the first time. Porous Ta samples with relative densities between 45 to 73% have been successfully fabricated and characterized for their mechanical properties. In vitro cell materials interactions, using human osteoblast cell line hFOB, have been accessed on these porous Ta structures and compared with porous Ti control samples. The results show that the Young’s modulus of porous Ta can be tailored between 1.5 to 20 GPa by changing the pore volume fraction between 27 and 55%. In vitro biocompatibility in terms of MTT assay and immunochemistry study showed excellent cellular adherence, growth and differentitation with abundant extracellular matrix formation on porous Ta structures compared to porous Ti control. These results indicate that porous Ta structures can promote enhanced/early biological fixation. The enhanced in vitro cell-materials interactions on porous Ta surface are attributed to chemistry and its high wettability and surface energy relative to porous Ti. Our results show that these laser processed porous Ta structures can find numerous applications, particularly among older patients, for metallic implants because of their excellent bioactivity. PMID:20132912

  14. Obtaining edaphic biostimulants/biofertilizers from different sewage sludges. Effects on soil biological properties.

    PubMed

    Rodríguez-Morgado, Bruno; Gómez, Isidoro; Parrado, Juan; García-Martínez, Ana M; Aragón, Carlos; Tejada, Manuel

    2015-01-01

    We studied the influence of six edaphic biostimulants/biofertilizers (BSs) manufactured by the pH-stat method from different sewage sludge (SS): SS1 (an anaerobic mature sludge, one year old), SS2 (an aerobic young sludge, without maturation) and SS3 (an aerobic mature sludge, four months old), not previously autoclaved (A) and autoclaved (B), by analysing their effects on soil biological properties. Soil enzymatic activities were measured at 1, 3, 5, 7, 15, 30 and 60 days of the incubation period, whereas the 16S rDNA-DGGE profiles were determined at 0, 5 and 60 days. The enzymatic activities were significantly stimulated. The highest stimulation was found in the B2 treatment followed by B3, A2, A3, B1 and A1 treatments. Increasing the number of lower molecular weight proteins in the BS enhances the stimulation of soil enzymatic activities. The application of BS caused at 5 days of the incubation period temporal variations in the soil bacterial community structure.

  15. Selective freezing of target biological tissues after injection of solutions with specific thermal properties.

    PubMed

    Yu, Tian-Hua; Liu, Jing; Zhou, Yi-Xin

    2005-04-01

    Cryosurgery is a minimally invasive surgical technique that employs the destructive effect of freezing to eradicate undesirable tissues. This paper proposes a flexible method to control the size and shape of the iceball by injecting solutions with specific thermal properties into the target tissues, to enhance freezing damage to the diseased tissues while preserving the normal tissues from injury. The cryosurgical procedure was performed using a minimally invasive cryoprobe cooled by liquid nitrogen (LN2) to obtain deep regional freezing. Several needle thermocouples were applied simultaneously to record the transient temperature to detect the freezing effect on the tissues. Simulation experiments on biological tissue (fresh pork) were performed in vitro and four different liquids were injected into the test materials; these were distilled water, an aqueous suspension of aluminum nanoparticles in water, ethanol, and a 10% solution of the cryoprotective agent dimethyl sulfoxide (Me2SO). The experimental results demonstrate that the localized injection of an appropriate solution could enhance the tumor-killing effect without altering the freezing conditions. The study also suggests the potential value of combining cryosurgery with other therapeutic methods, such as electrical, chemical, and thermal treatments, to develop new clinical modalities in the near future.

  16. A functionalizable polyester with free hydroxyl groups and tunable physiochemical and biological properties.

    PubMed

    You, Zhengwei; Cao, Haiping; Gao, Jin; Shin, Paul H; Day, Billy W; Wang, Yadong

    2010-04-01

    Polyesters with free functional groups allow facile modifications with biomolecules, which can lead to versatile biomaterials that afford controlled interactions with cells and tissues. Efficient synthesis of functionalizable polyesters (Functionalizable polymer is defined as a polymer with functional groups that readily react with biomolecules and functionalized biomaterial as one already modified with biomolecules.) is still a challenge that greatly limits the availability and widespread applications of biofunctionalized synthetic polymers. Here we report a simple route to prepare a functionalizable polyester, poly(sebacoyl diglyceride) (PSeD) bearing free hydroxyl groups. The key synthetic step is an epoxide ring-opening polymerization, instead of the traditional polycondensation that produces poly(glycerol sebacate) (PGS) (Wang YD, Ameer GA, Sheppard BJ, Langer R. A tough biodegradable elastomer. Nat Biotechnol 2002;20(6):602-6). PSeD has a more defined structure with mostly linear backbone, more free hydroxyl groups, higher molecular weight, and lower polydispersity than PGS. Crosslinking PSeD with sebacic acid yields a polymer five times tougher and more elastic than cured PGS. PSeD exhibits good cytocompatibility in vitro. Furthermore, functionalization by glycine proceeds with high efficiency. This versatile synthetic platform can offer a large family of biodegradable, functionalized polymers with tunable physiochemical and biological properties useful for a wide range of biomedical applications. Copyright 2010 Elsevier Ltd. All rights reserved.

  17. Calcium phosphate coatings obtained by Nd:YAG laser cladding: physicochemical and biologic properties.

    PubMed

    Lusquiños, F; De Carlos, A; Pou, J; Arias, J L; Boutinguiza, M; León, B; Pérez-Amor, M; Driessens, F C M; Hing, K; Gibson, I; Best, S; Bonfield, W

    2003-03-15

    The plasma spray (PS) technique is the most popular method commercially in use to produce calcium phosphate (CaP) coatings to promote fixation and osteointegration of the cementless prosthesis. Nevertheless, PS has some disadvantages, such as the poor coating-to-substrate adhesion, low mechanical strength, and brittleness of the coating. In order to overcome the drawbacks of plasma spraying, we introduce in this work a new method to apply a CaP coating on a Ti alloy using a well-known technique in the metallurgical field: laser surface cladding. The physicochemical characterization of the coatings has been carried out by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). The biologic properties of the coatings have been assessed in vitro with human osteoblast-like MG-63 cells. The overall results of this study affirm that the Nd:YAG laser cladding technique is a promising method in the biomedical field. Copyright 2003 Wiley Periodicals, Inc.

  18. Nano-composite scaffolds for bone tissue engineering containing silver nanoparticles: preparation, characterization and biological properties.

    PubMed

    Marsich, Eleonora; Bellomo, Francesca; Turco, Gianluca; Travan, Andrea; Donati, Ivan; Paoletti, Sergio

    2013-07-01

    In this study nano-composite scaffolds to be used as bone grafts have been endowed with antibacterial properties owing to the presence of silver nanoparticles. The alginate/hydroxyapatite composite scaffolds were prepared by internal gelation followed by a freeze-drying procedure to obtain a porous structure. The nanoparticles were prepared in presence of a lactose modified-chitosan and this colloidal solution was adsorbed on the scaffolds by exploiting electrostatic interactions. The adsorption and release of the silver from the composite scaffold was measured by ICP-AES and spectrofluorimetry measurements. Micro-computed tomography analysis of the scaffolds showed a homogeneous porous structure with average pore sizes of 341.5 μm and porosity of 80 %. In vitro biological tests (MTS and killing kinetics assays) demonstrated that silver does not affect the ability of the scaffolds to promote osteoblasts proliferation and that at the same time it exerts a strong bactericidal effect against both Gram+ and Gram- bacterial strains. Overall, the combined results indicate that these biocompatible antimicrobial scaffolds possess ideal characteristics for tissue engineering applications.

  19. A functionalizable polyester with free hydroxyl groups and tunable physiochemical and biological properties

    PubMed Central

    You, Zhengwei; Cao, Haiping; Gao, Jin; Shin, Paul H.; Day, Billy W.; Wang, Yadong

    2010-01-01

    Polyesters with free functional groups allow facile modifications with biomolecules, which can lead to versatile biomaterials that afford controlled interactions with cells and tissues. Efficient synthesis of functionalizable polyesters is still a challenge that greatly limits the availability and widespread applications of biofunctionalized synthetic polymers. Here we report a simple route to prepare a functionalizable polyester, poly(sebacoyl diglyceride) (PSeD) bearing free hydroxyl groups. The key synthetic step is an epoxide ring-opening polymerization, instead of the traditional polycondensation, that produces poly(glycerol sebacate) (PGS) [1]. PSeD has a more defined structure with mostly linear backbone, more free hydroxyl groups, higher molecular weight, and lower polydispersity than PGS. Crosslinking PSeD with sebacic acid yields a polymer five times tougher and more elastic than cured PGS. PSeD exhibits good cytocompatibility in vitro. Furthermore, functionalization by glycine proceeds with high efficiency. This versatile synthetic platform can offer a large family of biodegradable, functionalized polymers with tunable physiochemical and biological properties useful for a wide range of biomedical applications. PMID:20149441

  20. Biological and Immunogenicity Property of IgY Anti S. mutans ComD

    PubMed Central

    Bachtiar, E.W.; Bachtiar, B.M.; Soejoedono, R.D.; Wibawan, I.W.; Afdhal, A.

    2016-01-01

    Objective: This study aims to elucidate the effect of IgY anti ComD on the biological properties of Streptococcus mutans. (S. mutans) ComD is an interspecies quorum-sensing signaling receptor that plays an important role in biofilm formation by S. mutans. Materials and Methodology: Egg yolk IgY was produced by the immunization of chickens with a DNA vaccine containing the ComD DNA coding region. We evaluated the effect of the antibody on biofilm formation by S. mutans isolated from subjects with or without dental caries. We also assessed the immunoreactivity of the antibody against all isolates, and analyzed the protein profile of S. mutans by SDS-PAGE. Results: The ComD antibody was successfully induced in the hens’ eggs. It inhibited biofilm formation by all S. mutans isolates. In addition, the expression of some protein bands was affected after exposure to the antibody. Conclusion: IgY anti-S. mutans ComD reduces biofilm formation by this bacterium and alters the protein profile of S. mutans. PMID:27386013

  1. Isolation, Characterization and Biological Properties of Membrane Vesicles Produced by the Swine Pathogen Streptococcus suis.

    PubMed

    Haas, Bruno; Grenier, Daniel

    2015-01-01

    Streptococcus suis, more particularly serotype 2, is a major swine pathogen and an emerging zoonotic agent worldwide that mainly causes meningitis, septicemia, endocarditis, and pneumonia. Although several potential virulence factors produced by S. suis have been identified in the last decade, the pathogenesis of S. suis infections is still not fully understood. In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material. A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors. Biological assays confirmed that S. suis MVs possess active subtilisin-like protease (SspA) and DNase (SsnA). S. suis MVs degraded neutrophil extracellular traps, a property that may contribute to the ability of the bacterium to escape the host defense response. MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier. The present study brought evidence that S. suis MVs may play a role as a virulence factor in the pathogenesis of S. suis infections, and given their composition be an excellent candidate for vaccine development.

  2. Effects of sterilization methods on the physical, chemical, and biological properties of silk fibroin membranes.

    PubMed

    de Moraes, Mariana Agostini; Weska, Raquel Farias; Beppu, Marisa Masumi

    2014-05-01

    Silk fibroin has been widely explored for many biomedical applications, due to its biocompatibility and biodegradability. Sterilization is a fundamental step in biomaterials processing and it must not jeopardize the functionality of medical devices. The aim of this study was to analyze the influence of different sterilization methods in the physical, chemical, and biological characteristics of dense and porous silk fibroin membranes. Silk fibroin membranes were treated by several procedures: immersion in 70% ethanol solution, ultraviolet radiation, autoclave, ethylene oxide, and gamma radiation, and were analyzed by scanning electron microscopy, Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction, tensile strength and in vitro cytotoxicity to Chinese hamster ovary cells. The results indicated that the sterilization methods did not cause perceivable morphological changes in the membranes and the membranes were not toxic to cells. The sterilization methods that used organic solvent or an increased humidity and/or temperature (70% ethanol, autoclave, and ethylene oxide) increased the silk II content in the membranes: the dense membranes became more brittle, while the porous membranes showed increased strength at break. Membranes that underwent sterilization by UV and gamma radiation presented properties similar to the nonsterilized membranes, mainly for tensile strength and FTIR results. Copyright © 2013 Wiley Periodicals, Inc.

  3. The critical role of didodecyldimethylammonium bromide on physico-chemical, technological and biological properties of NLC.

    PubMed

    Carbone, C; Campisi, A; Manno, D; Serra, A; Spatuzza, M; Musumeci, T; Bonfanti, R; Puglisi, G

    2014-09-01

    Exploiting the experimental factorial design and the potentiality of Turbiscan AG Station, we developed and characterized unmodified and DDAB-coated NLC prepared by a low energy organic solvent free phase inversion temperature technique. A 22 full factorial experimental design was developed in order to study the effects of two independent variables (DDAB and ferulic acid) and their interaction on mean particle size and zeta potential values. The factorial planning was validated by ANOVA analysis; the correspondence between the predicted values of size and zeta and those measured experimentally confirmed the validity of the design and the equation applied for its resolution. The DDAB-coated NLC were significantly affected in their physico-chemical properties by the presence of DDAB, as showed by the results of the experimental design. The coated NLC showed higher physical stability with no particles aggregation compared to the unmodified NLC, as demonstrated by Turbiscan(®) AGS measurements. X-ray diffraction, Raman spectroscopy and Cryo-TEM images allowed us to assert that DDAB plays a critical role in increasing the lipids structural order with a consequent enhancement of the NLC physical stability. Furthermore, the results of the in vitro biological studies allow the revisiting of the role of DDAB to the benefit of glioblastoma treatment, due to its efficacy in increasing the NLC uptake and reducing the viability of human glioblastoma cancer cells (U87MG).

  4. Effects of barriers on chemical and biological properties of two dual resin cements.

    PubMed

    Nocca, Giuseppina; Iori, Andrea; Rossini, Carlo; Martorana, Giuseppe E; Ciasca, Gabriele; Arcovito, Alessandro; Cordaro, Massimo; Lupi, Alessandro; Marigo, Luca

    2015-06-01

    The aim of this study was to investigate the degree of conversion, monomer release, and cytotoxicity of two dual-cure resin cements (Cement-One and SmartCem2), light-cured across two indirect restorative materials in an attempt to simulate in vitro the clinical conditions. The results obtained show that the degree of conversion was influenced by both barriers, but the effect of the composite material was greater than that of the ceramic one. The amount of monomers released from the polymerized materials in the absence of barriers was significantly lower than that released in the presence of either the ceramic or the composite barrier. However, a higher amount of monomers was released in the presence of the ceramic barrier. All materials, in all the experimental conditions employed, induced slight cytotoxicity (5-10%) on human pulp cells. Our examinations showed that the two resin cements had similar chemical and biological properties. The decreased degree of conversion of the dual-curing self-adhesive composite showed that the light-curing component of these materials has an important role in the polymerization process. In clinical practice, it is therefore important to pay attention to the thickness of the material used for the reconstruction. © 2015 Eur J Oral Sci.

  5. DNA binding properties and biological evaluation of dihydropyrimidinones derivatives as potential antitumor agents

    NASA Astrophysics Data System (ADS)

    Wang, Gongke; Li, Xiangrong; Gou, Yaping; Chen, Yuhan; Yan, Changling; Lu, Yan

    2013-10-01

    The binding properties of two medicinally important dihydropyrimidinones derivatives 5-(Ethoxycarbonyl)-6-methyl-4-phenyl-3,4-dihydropyrimidin-2(1H)-one (EMPD) and 5-(Ethoxycarbonyl)-6-methyl-4-(4-chlorophenyl)-3,4-dihydropyrimidin-2(1H)-one (EMCD) with calf-thymus DNA (ctDNA) were investigated by spectroscopy, viscosity, isothermal titration calorimetry (ITC) and molecular modeling techniques. Simultaneously, their biological activities were evaluated with MTT assay method. The binding constants determined with spectroscopic titration and ITC were found to be in the same order of 104 M-1. According to the results of viscosity studies, fluorescence competitive binding experiment and ITC investigations, intercalative binding was evaluated as the dominant binding modes between the two compounds and ctDNA. Furthermore, the results of molecular modeling corroborated those obtained from spectroscopic, viscosimetric and ITC investigations. Evaluation of the antitumor activities of the two derivatives against different tumor cell lines proved that they exhibited significant tumor cell inhibition rate, accordingly blocking DNA transcription and replication. The present results favor the development of potential drugs related with dihydropyrimidinones derivatives in the treatment of some diseases.

  6. Biological properties of a biomimetic membrane for guided tissue regeneration: a study in rat calvarial defects.

    PubMed

    Zhang, Jingchao; Huang, Cui; Xu, Qian; Mo, Anchun; Li, Jidong; Zuo, Yi

    2010-04-01

    The biological properties of nano-hydroxyapatite/polyamide (nHA/PA66) membrane as a guided tissue regeneration barrier were investigated based on a critical-size calvarial defect model. Thirty-six Sprague-Dawley rats were divided into four groups: nHA/PA66 membranes, control treated with expanded polytetrafluoroethylene (e-PTFE) membranes, control treated with PA membranes and blank. Bone regeneration in each group was evaluated using morphological, serological, radiographic and histological techniques at 1, 4 and 8 weeks, respectively, post-operation. Slight degradation of nHA/PA66 membranes was observed by a scanning electron microscope (SEM) at 4 and 8 weeks. The serum alkaline phosphatase level and the integral optical density of neo-bone were significantly higher in the nHA/PA66 group than those in the PA group and blank (P<0.05). Radiographic and histological analysis showed a fully closed cranial defect for both the nHA/PA66 group and the e-PTFE group at 8 weeks. No remarkable difference was found between the nHA/PA66 group and the e-PTFE group at each time interval. nHA/PA66 membrane promoted bone regeneration as effectively as conventional e-PTFE membrane. Based on a rat study, nHA/PA66 membrane provides a promising alternative to e-PTFE membrane due to the absence of requirement for a second surgery.

  7. Retro analog concept: comparative study on physico-chemical and biological properties of selected antimicrobial peptides.

    PubMed

    Neubauer, Damian; Jaśkiewicz, Maciej; Migoń, Dorian; Bauer, Marta; Sikora, Karol; Sikorska, Emilia; Kamysz, Elżbieta; Kamysz, Wojciech

    2017-07-29

    Increasing drug resistance of common pathogens urgently needs discovery of new effective molecules. Antimicrobial peptides are believed to be one of the possible solutions of this problem. One of the approaches for improvement of biological properties is reversion of the sequence (retro analog concept). This research is based on investigation of antimicrobial activity against Gram-positive, Gram-negative bacteria, and fungi, hemolysis of erythrocytes, interpretation of the circular dichroism spectra, measurement of counter-ion content, and assessment of the peptide hydrophobicity and self-assembly using reversed-phase chromatography. The experiments were conducted using the following peptides: aurein 1.2, CAMEL, citropin 1.1, omiganan, pexiganan, temporin A, and their retro analogs. Among the compounds studied, only retro omiganan showed an enhanced antimicrobial and a slightly increased hemolytic activity as compared to parent molecule. Moreover, retro pexiganan exhibited high activity towards Klebsiella pneumoniae, whereas pexiganan was in general more or equally active against the rest of tested microorganisms. Furthermore, the determined activity was closely related to the peptide hydrophobicity. In general, the reduced hemolytic activity correlates with lower antimicrobial activity. The tendency to self-association and helicity fraction in SDS seems to be correlated. The normalized RP-HPLC-temperature profiles of citropin 1.1 and aurein 1.2, revealed an enhanced tendency to self-association than that of their retro analogs.

  8. Vesicles in Nature and the Laboratory: Elucidation of Their Biological Properties and Synthesis of Increasingly Complex Synthetic Vesicles.

    PubMed

    Fernandez-Trillo, Francisco; Grover, Liam M; Stephenson-Brown, Alex; Harrison, Paul; Mendes, Paula M

    2017-03-13

    The important role of vesicles in many aspects of cell function is well-recognized, but only recently have sophisticated imaging techniques begun to reveal their ubiquity in nature. While we further our understanding of the biological properties of vesicles and their physiological functions, increasingly elegant artificial vesicles are being developed for a wide range of technological applications and basic research. Herein, we examine the state of the art of biological and synthetic vesicles and place their biological features in the context of recent synthetic developments, thus providing a unique overview of these complex and rapidly developing fields. The challenges and opportunities associated with future biological and synthetic studies of vesicles are also presented. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Study Under AC Stimulation on Excitement Properties of Weighted Small-World Biological Neural Networks with Side-Restrain Mechanism

    NASA Astrophysics Data System (ADS)

    Yuan, Wu-Jie; Luo, Xiao-Shu; Jiang, Pin-Qun

    2007-02-01

    In this paper, we propose a new model of weighted small-world biological neural networks based on biophysical Hodgkin-Huxley neurons with side-restrain mechanism. Then we study excitement properties of the model under alternating current (AC) stimulation. The study shows that the excitement properties in the networks are preferably consistent with the behavior properties of a brain nervous system under different AC stimuli, such as refractory period and the brain neural excitement response induced by different intensities of noise and coupling. The results of the study have reference worthiness for the brain nerve electrophysiology and epistemological science.

  10. The organization of biological sequences into constrained and unconstrained parts determines fundamental properties of genotype–phenotype maps

    PubMed Central

    Greenbury, S. F.; Ahnert, S. E.

    2015-01-01

    Biological information is stored in DNA, RNA and protein sequences, which can be understood as genotypes that are translated into phenotypes. The properties of genotype–phenotype (GP) maps have been studied in great detail for RNA secondary structure. These include a highly biased distribution of genotypes per phenotype, negative correlation of genotypic robustness and evolvability, positive correlation of phenotypic robustness and evolvability, shape-space covering, and a roughly logarithmic scaling of phenotypic robustness with phenotypic frequency. More recently similar properties have been discovered in other GP maps, suggesting that they may be fundamental to biological GP maps, in general, rather than specific to the RNA secondary structure map. Here we propose that the above properties arise from the fundamental organization of biological information into ‘constrained' and ‘unconstrained' sequences, in the broadest possible sense. As ‘constrained' we describe sequences that affect the phenotype more immediately, and are therefore more sensitive to mutations, such as, e.g. protein-coding DNA or the stems in RNA secondary structure. ‘Unconstrained' sequences, on the other hand, can mutate more freely without affecting the phenotype, such as, e.g. intronic or intergenic DNA or the loops in RNA secondary structure. To test our hypothesis we consider a highly simplified GP map that has genotypes with ‘coding' and ‘non-coding' parts. We term this the Fibonacci GP map, as it is equivalent to the Fibonacci code in information theory. Despite its simplicity the Fibonacci GP map exhibits all the above properties of much more complex and biologically realistic GP maps. These properties are therefore likely to be fundamental to many biological GP maps. PMID:26609063

  11. The organization of biological sequences into constrained and unconstrained parts determines fundamental properties of genotype-phenotype maps.

    PubMed

    Greenbury, S F; Ahnert, S E

    2015-12-06

    Biological information is stored in DNA, RNA and protein sequences, which can be understood as genotypes that are translated into phenotypes. The properties of genotype-phenotype (GP) maps have been studied in great detail for RNA secondary structure. These include a highly biased distribution of genotypes per phenotype, negative correlation of genotypic robustness and evolvability, positive correlation of phenotypic robustness and evolvability, shape-space covering, and a roughly logarithmic scaling of phenotypic robustness with phenotypic frequency. More recently similar properties have been discovered in other GP maps, suggesting that they may be fundamental to biological GP maps, in general, rather than specific to the RNA secondary structure map. Here we propose that the above properties arise from the fundamental organization of biological information into 'constrained' and 'unconstrained' sequences, in the broadest possible sense. As 'constrained' we describe sequences that affect the phenotype more immediately, and are therefore more sensitive to mutations, such as, e.g. protein-coding DNA or the stems in RNA secondary structure. 'Unconstrained' sequences, on the other hand, can mutate more freely without affecting the phenotype, such as, e.g. intronic or intergenic DNA or the loops in RNA secondary structure. To test our hypothesis we consider a highly simplified GP map that has genotypes with 'coding' and 'non-coding' parts. We term this the Fibonacci GP map, as it is equivalent to the Fibonacci code in information theory. Despite its simplicity the Fibonacci GP map exhibits all the above properties of much more complex and biologically realistic GP maps. These properties are therefore likely to be fundamental to many biological GP maps.

  12. Predicting neurological Adverse Drug Reactions based on biological, chemical and phenotypic properties of drugs using machine learning models.

    PubMed

    Jamal, Salma; Goyal, Sukriti; Shanker, Asheesh; Grover, Abhinav

    2017-04-13

    Adverse drug reactions (ADRs) have become one of the primary reasons for the failure of drugs and a leading cause of deaths. Owing to the severe effects of ADRs, there is an urgent need for the generation of effective models which can accurately predict ADRs during early stages of drug development based on integration of various features of drugs. In the current study, we have focused on neurological ADRs and have used various properties of drugs that include biological properties (targets, transporters and enzymes), chemical properties (substructure fingerprints), phenotypic properties (side effects (SE) and therapeutic indications) and a combinations of the two and three levels of features. We employed relief-based feature selection technique to identify relevant properties and used machine learning approach to generated learned model systems which would predict neurological ADRs prior to preclinical testing. Additionally, in order to explain the efficiency and applicability of the models, we tested them to predict the ADRs for already existing anti-Alzheimer drugs and uncharacterized drugs, respectively in side effect resource (SIDER) database. The generated models were highly accurate and our results showed that the models based on chemical (accuracy 93.20%), phenotypic (accuracy 92.41%) and combination of three properties (accuracy 94.18%) were highly accurate while the models based on biological properties (accuracy 82.11%) were highly informative.

  13. Mexican Arnica (Heterotheca inuloides Cass. Asteraceae: Astereae): Ethnomedical uses, chemical constituents and biological properties.

    PubMed

    Rodríguez-Chávez, José Luis; Egas, Verónica; Linares, Edelmira; Bye, Robert; Hernández, Tzasna; Espinosa-García, Francisco J; Delgado, Guillermo

    2017-01-04

    Heterotheca inuloides Cass. (Asteraceae) has been traditionally used to treat a wide range of diseases in Mexico in the treatment of rheumatism, topical skin inflammation, muscular pain colic, and other painful conditions associated with inflammatory processes, additionally has been used to treat dental diseases, and gastrointestinal disorders. This species has also been used for the treatment of cancer and diabetes. This review provides up-to-date information on the botanical characterization, traditional uses, chemical constituents, as well as the biolological activities of H. inuloides. A literature search was conducted by analyzing the published scientific material. Information related to H. inuloides was collected from various primary information sources, including books, published articles in peer-reviewed journals, monographs, theses and government survey reports. The electronic search of bibliographic information was gathered from accepted scientific databases such as Scienfinder, ISI Web of Science, Scielo, LILACS, Redalyc, Pubmed, SCOPUS and Google Scholar. To date, more than 140 compounds have been identified from H. inuloides, including cadinane sesquiterpenes, flavonoids, phytosterols, triterpenes, benzoic acid derivatives, and other types of compounds. Many biological properties associated with H. inuloides. Many studies have shown that the extracts and some compounds isolated from this plant exhibit a broad spectrum of biological activities such as antioxidant, antitumor, anti-inflammatory, cytotoxic, and chelating activities, as well as insecticidal and phytotoxic activity. To date, reports on the toxicity of H. inuloides are limited. A comprehensive analysis of the literature obtained through the above-mentioned sources confirmed that ethnomedical uses of H. inuloides have been recorded in Mexico to treat rheumatism, pain, and conditions associated with inflammatory processes. Pharmacological studies have demonstrated the activity of certain

  14. A review of the physical properties and biological effects of the high amplitude acoustic field used in extracorporeal lithotripsy.

    PubMed

    Coleman, A J; Saunders, J E

    1993-01-01

    Extracorporeal shockwave lithotripsy (ESWL) has now been used for more than a decade in the treatment of urinary stone disease. During this period there has been a wide range of studies on the physical properties of the high-amplitude focussed fields used in ESWL and the biological effects of exposure to such fields, including their ability to fragment hard concretions. These studies form a distinct body of knowledge whose relevance to the broader literature on biological effects from lower amplitude exposures has yet to be fully evaluated. This review attempts to present the main results of biological-effects studies in ESWL along with what is known of the physical properties of lithotripsy fields with the aim of assisting this evaluation. In general, the reported biological effects of lithotripsy fields are compatible with those that have been observed at those lower amplitudes of focussed pulsed ultrasound in which transient cavitation is the dominant mechanism of interaction. The relatively large amplitudes and low frequencies in ESWL, however, make it a more potent generator of transient cavitation than most other forms of medical ultrasound. Biological-effects studies with lithotripsy fields may, therefore, be expected to extend our understanding of the nature of transient cavitation and, in particular, its effects in mammalian tissue.

  15. Conformational assembly and biological properties of collagen mimetic peptides and their thermally responsive polymer conjugates

    NASA Astrophysics Data System (ADS)

    Krishna, Ohm Divyam

    2011-12-01

    Collagens are one of the most abundant proteins found in body tissues and organs, endowing structural integrity, mechanical strength, and multiple biological functions. Destabilized collagen inside human body leads to various degenerative diseases (ex. osteoarthritis) and ageing. This has continued to motivate the design of synthetic peptides and bio-synthetic polypeptides to closely mimic the native collagens in terms of triple helix structure and stability, potential for higher order assembly, and biological properties. However, the widespread application of de novo collagens has been limited in part by the need for hydroxylated proline in the formation of stable triple helical structures. To address this continued need, a hydroxyproline-free, thermally stable collagen-mimetic peptide (CLP-Cys) was rationally designed via the incorporation of electrostatically stabilized amino acid triplets. CLP-Cys was synthesized via solid phase peptide synthesis. The formation and stability of the triple helical structure were indicated via circular dichroism (CD) experiments and confirmed via differential scanning calorimetry (DSC) results. CLP-Cys also self-assembled into nano-rods and micro-fibrils, as evidenced via a combination of dynamic light scattering and transmission electron microscopy. Given the high thermal stability and its propensity for higher-order assembly, CLP-Cys was further functionalized at both the ends with a thermally responsive polymer, poly(diethylene glycol methyl ether methacrylate), (PDEGMEMA) to synthesize a biohybrid triblock copolymer. The CD results indicated that the triple helical form is retained, the thermal unfolding is sustained and helix to coil transition is reversible in the triblock hybrid context. The LCST of PDEGMEMA homopolymer (26 °C) is increased (to 35 °C) upon conjugation to the hydrophilic collagen peptide domain. Further, a combination of static light scattering, Cryo-SEM, TEM and confocal microscopy elucidated that the

  16. The effect of terminal sterilization on the material properties and in vivo remodeling of a porcine dermal biologic scaffold.

    PubMed

    Dearth, Christopher L; Keane, Timothy J; Carruthers, Christopher A; Reing, Janet E; Huleihel, Luai; Ranallo, Christian A; Kollar, Elizabeth W; Badylak, Stephen F

    2016-03-01

    Biologic scaffolds composed of extracellular matrix are commonly used in a variety of surgical procedures. The Food and Drug Administration typically regulates biologic scaffolds as medical devices, thus requiring terminal sterilization prior to clinical use. However, to date, no consensus exists for the most effective yet minimally destructive sterilization protocol for biologic scaffold materials. The objective of the present study was to characterize the effect of ethylene oxide, gamma irradiation and electron beam (e-beam) irradiation on the material properties and the elicited in vivo remodeling response of a porcine dermal biologic scaffold. Outcome measures included biochemical, structural, and mechanical properties as well as cytocompatibility in vitro. In vivo evaluation utilized a rodent model to examine the host response to the materials following 7, 14, and 35 days. The host response to each experimental group was determined by quantitative histologic methods and by immunolabeling for macrophage polarization (M1/M2). In vitro results show that increasing irradiation dosage resulted in a dose dependent decrease in mechanical properties compared to untreated controls. Ethylene oxide-treated porcine dermal ECM resulted in decreased DNA content, extractable total protein, and bFGF content compared to untreated controls. All ETO treated, gamma irradiated, and e-beam irradiated samples had similar cytocompatibility scores in vitro. However, in vivo results showed that increasing dosages of e-beam and gamma irradiation elicited an increased rate of degradation of the biologic scaffold material following 35 days. The FDA typically regulates biologic scaffolds derived from mammalian tissues as medical devices, thus requiring terminal sterilization prior to clinical use. However, there is little data and no consensus for the most effective yet minimally destructive sterilization protocol for such materials. The present study characterized the effect of common

  17. The influence comparing of activated biochar and conventional biochar on the soil biological properties

    NASA Astrophysics Data System (ADS)

    Dvořáčková, Helena; Mykajlo, Irina; Záhora, Jaroslav

    2016-04-01

    In our experiment we have used biochar. This material is the product of the pyrolysis that has shown a positive effect on numerous physical and chemical soil properties. However, its influence on the biological component of the soil is very variable. A number of toxic substances that inhibit the soil productivity may be produced during pyrolysis process. The experiment dealt with the hypothesis concerning biochar toxicity reduction by simulating natural processes in the soil. Biochar has been exposed to aeration in the aquatic environment, enriched with nutrients and a source of native soil microflora. It has been created 6 variants in total, each with four replications. The soils samples have been placed in a phytotron for 90 days. Variants consisted of the soil with fertilizers adding (compost, biochar, activated biochar) and have been prepared as well as variants containing compost and biochar and activated biochar optionally. The highest aboveground biomass production has been estimated in variants containing compost, while the lowest production - in the variants containing conventional biochar. During production comparing of the variants with the conventional biochar, activated biochar and control samples it has been evident that activated biochar promotes plant growth, and in contradiction conventional biochar inhibits it. We will approach to the same conclusions when comparing variants with a combination of conventional biochar + compost and activated biochar + compost. Mineral nitrogen leaching has been another investigated parameter. The highest leaching has occurred in the control variant, while the lowest - in the variant with activated biochar (the leaching of nitrate nitrogen has been negligeable). Our results suggest that activated biochar has the potential; however, it is necessary to carry out similar experiments in the field conditions.

  18. Effects of selenium on biological and physiological properties of the duckweed Landoltia punctata.

    PubMed

    Zhong, Y; Cheng, J J

    2016-09-01

    Duckweed can be used for bioremediation of selenium (Se) polluted water because of its capability of absorbing minerals from growing media. However, the presence of Se in the media may affect the growth of the duckweed. Landoltia punctata 7449 has been studied for its changes in chemical and biological properties with the presence of Se in the media. The duckweed was cultivated over a 12-day period at different initial concentrations of selenite (Na2 SeO3 ) from 0 to 80 μmol·l(-1) . The growth rate, the organic and total Se contents, the activity of antioxidant enzymes, the photosynthetic pigment contents, the chlorophyll a fluorescence OJIP transient, and the ultrastructure of the duckweed were monitored during the experiment. The results have shown that Se at low concentrations of ≤20 μmol·l(-1) promoted the growth of the L. punctata and inhibited lipid peroxidation. Substantial increases in duckweed growth rate and organic Se content in the duckweed were observed at low Se concentrations. The anti-oxidative effect occurred likely with the increases in guaiacol peroxidase, catalase and superoxide dismutase activities as well as the amount of photosynthetic pigments. However, negative impact to the duckweed was observed when the L. punctata was exposed to high Se concentrations (≥40 μmol·l(-1) ), in which the duckweed growth was inhibited by the selenium. The results indicate that L. punctata 7449 can be used for bioremediation of selenium (Se) polluted water when the Se concentration is ≤20 μmol·l(-1) . © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  19. A review on chemical and biological properties of Cayratia trifolia Linn. (Vitaceae)

    PubMed Central

    Kumar, Dinesh; Kumar, Sunil; Gupta, Jyoti; Arya, Renu; Gupta, Ankit

    2011-01-01

    Cayratia trifolia Linn. Domin Syn. Vitis trifolia (Family: Vitaceae) is commonly known as Fox grape in English; Amlabel, Ramchana in Hindi and Amlavetash in Sanskrit. It is native to India, Asia and Australia. It is a perennial climber having trifoliated leaves with 2-3 cm long petioles and ovate to oblong-ovate leaflets. Flowers are small greenish white and brown in color. Fruits are fleshy, juicy, dark purple or black, nearly spherical, about 1 cm in diameter. It is found throughout the hills in India. This perennial climber is also found in the hotter part of India from Jammu and Rajasthan to Assam extending into the peninusular India upto 600 m height. Whole plant of Cayratia trifolia has been reported to contain yellow waxy oil, steroids/terpenoids, flavonoids, tannins upon preliminary phytochemical screening. Leaves contain stilbenes (piceid, reveratrol, viniferin, ampelopsin). Stem, leaves, roots are reported to possess hydrocyanic acid, delphinidin and several flavonoids such as cyanidin is reported in the leaves. This plant also contains kaempferol, myricetin, quercetin, triterpenes and epifriedelanol. Infusion of seeds along with extract of tubers is traditionally given orally to diabetic patients to check sugar level of blood. Paste of tuberous is applied on the affected part in the treatment of snake bite. Whole plant is used as diuretic, in tumors, neuralgia and splenopathy. Its climbers wrapped around the neck of frantic bullock and poultice of leaves are used to yoke sores of bullock. The bark extract shows the antiviral, antibacterial, antiprotozoal, hypoglycemic, anticancer and diuretic activity. This article focuses on the upgraded review on chemical and biological properties of Cayratia trifolia Linn. and triggers further investigation on this plant. PMID:22279376

  20. Crop residue management and fertilization effects on soil organic matter and associated biological properties.

    PubMed

    Zhao, Bingzi; Zhang, Jiabao; Yu, Yueyue; Karlen, Douglas L; Hao, Xiying

    2016-09-01

    Returning crop residue may result in nutrient reduction in soil in the first few years. A two-year field experiment was conducted to assess whether this negative effect is alleviated by improved crop residue management (CRM). Nine treatments (3 CRM and 3 N fertilizer rates) were used. The CRM treatments were (1) R0: 100 % of the N using mineral fertilizer with no crop residues return; (2) R: crop residue plus mineral fertilizer as for the R0; and (3) Rc: crop residue plus 83 % of the N using mineral and 17 % manure fertilizer. Each CRM received N fertilizer rates at 270, 360, and 450 kg N ha(-1) year(-1). At the end of the experiment, soil NO3-N was reduced by 33 % from the R relative to the R0 treatment, while the Rc treatment resulted in a 21 to 44 % increase in occluded particulate organic C and N, and 80 °C extracted dissolved organic N, 19 to 32 % increase in microbial biomass C and protease activity, and higher monounsaturated phospholipid fatty acid (PLFA):saturated PLFA ratio from stimulating growth of indigenous bacteria when compared with the R treatment. Principal component analysis showed that the Biolog and PLFA profiles in the three CRM treatments were different from each other. Overall, these properties were not influenced by the used N fertilizer rates. Our results indicated that application of 17 % of the total N using manure in a field with crop residues return was effective for improving potential plant N availability and labile soil organic matter, primarily due to a shift in the dominant microorganisms.

  1. Studies of the biological properties of human beta-defensin 1.

    PubMed

    Pazgier, Marzena; Prahl, Adam; Hoover, David M; Lubkowski, Jacek

    2007-01-19

    Defensins are small (30-45 amino acid residues) cationic proteins with broad antimicrobial activity against many bacteria and fungi, some enveloped viruses, and other activities such as chemoattraction of a range of different cell types to the sites of inflammation. These proteins represent attractive targets for developing novel antimicrobial agents and modulators of immune responses with therapeutic applicability. In this report, we present the results of functional and structural studies of 26 single-site mutants of human beta-defensin 1 (hBD1). All mutants were assayed for antimicrobial activity against Escherichia coli (ATCC strain 25922) and for chemotactic activity with CCR6-transfected HEK293 cells. To analyze the structural implications of mutagenesis and to verify the correctness of the disulfide connectivity, we used x-ray crystallography to conduct complete structural studies for 10 mutants in which the topology of disulfides was the same as in the native hBD1. Mutations did not induce significant changes of the tertiary structure, suggesting that the observed alterations of biological properties of the mutants were solely associated with changes in the respective side chains. We found that cationic residues located near the C terminus (Arg(29), Lys(31), Lys(33), and Lys(36)) of hBD1 define most of the anti-E. coli in vitro activity of this protein. In turn, nearly all mutations altering the CCR6-mediated chemotaxis are located at one area of the protein, defined by the N-terminal alpha-helical region (Asp(1)... Ser(8)) and a few topologically adjacent residues (Lys(22), Arg(29), and Lys(33)). These experimental results allow for the first time drafting of the CCR6-epitope for a defensin molecule.

  2. Setting time affects in vitro biological properties of root canal sealers.

    PubMed

    Camargo, Carlos Henrique R; Oliveira, Tatiana R; Silva, Gleyce O; Rabelo, Sylvia B; Valera, Marcia C; Cavalcanti, Bruno N

    2014-04-01

    Biocompatibility of root canal sealers is important because of the long-term contact of their eluates and/or degradation products with periapical tissues. The literature still lacks studies about the genotoxic effects of these materials and the influence of setting time on biological properties. The cytotoxicity and genotoxicity of an epoxy resin-based sealer (AH Plus), a single methacrylate-based sealer (EndoRez), and a silicone-based sealer (RoekoSeal) were assessed. Chinese hamster fibroblasts (V79) were cultured and exposed to different dilutions of extracts from the sealers that were left to set for 0, 12, and 24 hours before contact with culture medium. Cell viability was measured by the methyl-thiazol-diphenyltetrazolium assay. Genotoxicity was assessed by the comet assay. Data were statistically analyzed by Kruskal-Wallis and Dunn tests (P < .05). Root canal sealers were statistically more cytotoxic than the untreated control group, except for the silicon-based sealer. Cell viability ranking was the following (from the most to the least cytotoxic): methacrylate-based > epoxy resin-based > silicone-based. The setting time influenced the epoxy resin-based sealer cytotoxicity (decreased at 12 hours) and the general genotoxicity (increased at 24 hours). DNA damage ranking was the following (from the most to the least genotoxic): methacrylate-based > silicone-based = epoxy resin-based. The setting time had influence on the cytotoxicity of the epoxy resin-based sealer and genotoxicity of all tested sealers. The methacrylate-based sealer was the most cytotoxic, and the silicone-based sealer was not cytotoxic. Genotoxicity was observed for all sealers. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. Energies and physicochemical properties of cation-π interactions in biological structures.

    PubMed

    Du, Qi-Shi; Meng, Jian-Zong; Liao, Si-Ming; Huang, Ri-Bo

    2012-04-01

    The cation-π interactions occur frequently within or between proteins due to six (Phe, Tyr, Trp, Arg, Lys, and His) of the twenty natural amino acids potentially interacting with metallic cations via these interactions. In this study, quantum chemical calculations and molecular orbital (MO) theory are used to study the energies and properties of cation-π interactions in biological structures. The cation-π interactions of H⁺ and Li⁺ are similar to hydrogen bonds and lithium bonds, respectively, in which the small, naked cations H⁺ and Li⁺ are buried deep within the π-electron density of aromatic molecules, forming stable cation-π bonds that are much stronger than the cation-π interactions of other alkali metal cations. The cation-π interactions of metallic cations with atomic masses greater than that of Li⁺ arise mainly from the coordinate bond comprising empty valence atomic orbitals (AOs) of metallic cations and π-MOs of aromatic molecules, though electrostatic interactions may also contribute to the cation-π interaction. The binding strength of cation-π interactions is determined by the charge and types of AOs in the metallic cations. Cation-π interaction energies are distance- and orientation-dependent; energies decrease with the distance (r) and the orientation angle (θ). In solution, the cation-π energies decrease with the increase of the dielectric constant (ɛ) of the solvent; however, solvation has less influence on the H⁺-π and H₃O⁺-π interactions than on interactions with other cations. The conclusions from this study provide useful theoretical insights into the nature of cation-π interactions and may contribute to the development of better force field parameters for describing the molecular dynamics of cation-π interactions within and between proteins.

  4. [Biological properties of lateritic red soil and their relationships with soil fertility in Southern China under different land use types].

    PubMed

    Zhang, Jing; Gao, Yun-Hua; Zhang, Chi; Zhou, Bo; Li, Jing-Juan; Yang, Xiao-Xue; Xu, Huan; Dai, Jun

    2013-12-01

    Taking the lateritic red soil on a typical slopeland in Southern China as test object, this paper studied the soil microbial properties, enzyme activities, and their relationships with soil fertility under four land use types (newly cultivated dryland, shrub land, Eucalyptus land, and orchard). There existed significant differences in the soil biological properties under different land use types, among which, orchard soil had the highest microbial quantity and enzyme activities, newly cultivated dryland soil had the fastest soil respiration rate, the fewest soil microorganism quantity, and the lowest enzyme activities, whereas shrub land and woodland soils had the biological properties ranged between newly cultivated dryland and orchard soils, and there was a high similarity in the biological properties between shrub land and woodland soils. Under different land use types, the soil microbial quantity and enzyme activities were positively correlated with soil organic carbon and most of the soil nutrients. It was suggested the soils with high soil organic matter content and high fertility level were beneficial to the soil microbial growth and enzyme activities.

  5. Biological Motion Preference in Humans at Birth: Role of Dynamic and Configural Properties

    ERIC Educational Resources Information Center

    Bardi, Lara; Regolin, Lucia; Simion, Francesca

    2011-01-01

    The present study addresses the hypothesis that detection of biological motion is an intrinsic capacity of the visual system guided by a non-species-specific predisposition for the pattern of vertebrate movement and investigates the role of global vs. local information in biological motion detection. Two-day-old babies exposed to a biological…

  6. Grammatical Gender and Inferences about Biological Properties in German-Speaking Children

    ERIC Educational Resources Information Center

    Saalbach, Henrik; Imai, Mutsumi; Schalk, Lennart

    2012-01-01

    In German, nouns are assigned to one of the three gender classes. For most animal names, however, the assignment is independent of the referent's biological sex. We examined whether German-speaking children understand this independence of grammar from semantics or whether they assume that grammatical gender is mapped onto biological sex when…

  7. Grammatical Gender and Inferences about Biological Properties in German-Speaking Children

    ERIC Educational Resources Information Center

    Saalbach, Henrik; Imai, Mutsumi; Schalk, Lennart

    2012-01-01

    In German, nouns are assigned to one of the three gender classes. For most animal names, however, the assignment is independent of the referent's biological sex. We examined whether German-speaking children understand this independence of grammar from semantics or whether they assume that grammatical gender is mapped onto biological sex when…

  8. Biological Motion Preference in Humans at Birth: Role of Dynamic and Configural Properties

    ERIC Educational Resources Information Center

    Bardi, Lara; Regolin, Lucia; Simion, Francesca

    2011-01-01

    The present study addresses the hypothesis that detection of biological motion is an intrinsic capacity of the visual system guided by a non-species-specific predisposition for the pattern of vertebrate movement and investigates the role of global vs. local information in biological motion detection. Two-day-old babies exposed to a biological…

  9. [Piezoelectric property of novel biological piezoelectric ceramic HALNK and its effect on the functional expression of rat osteoblast cells].

    PubMed

    Wang, Peng; Zhang, Jin-Chao; Zhang, Xiao-Zhou; Liu, Zhi-Qin; Chen, Que-Ting; Sun, Jing; Chen, Zhi-Qing

    2009-09-01

    To test the Piezoelectric property of novel biological piezoelectric ceramic HALNK and its effect on the proliferation and differentiation of rat osteoblast cells. The biological piezoelectric ceramic HALNK1/9 and HALNK5/5 were prepared by mixing Hydroxyapatite (HA) with lithium sodium potassium niobate (LNK) piezoelectric ceramic at a ratio of 1/9 and 5/5 (wt/wt), respectively. After poling treatment, the piezoelectric constants were measured. The osteoblast cells were then seeded on the surfaces of HALNK. The proliferation and differentiation activities of the osteoblast cells were evaluated by MTT assays, ALP activities and scanning electron microscopy examinations. Cells grown on the surfaces of HALNK showed normal morphology, and had better proliferation and differentiation activities than the control. The growth of osteoblastic cells on the surface of HALNK1/9 was significantly better than others. The surface of HALNK 1/9 possesses better piezoelectric property and osteogenesis potential than HALNK5/5.

  10. Physicochemical and biological properties of oxovanadium(IV), cobalt(II) and nickel(II) complexes with oxydiacetate anions.

    PubMed

    Wyrzykowski, Dariusz; Kloska, Anna; Pranczk, Joanna; Szczepańska, Aneta; Tesmar, Aleksandra; Jacewicz, Dagmara; Pilarski, Bogusław; Chmurzyński, Lech

    2015-03-01

    The potentiometric and conductometric titration methods have been used to characterize the stability of series of VO(IV)-, Co(II)- and Ni(II)-oxydiacetato complexes in DMSO-water solutions containing 0-50 % (v/v) DMSO. The influence of DMSO as a co-solvent on the stability of the complexes as well as the oxydiacetic acid was evaluated. Furthermore, the reactivity of the complexes towards superoxide free radicals was assessed by employing the nitro blue tetrazolium (NBT) assay. The biological properties of the complexes were investigated in relation to their cytoprotective activity against the oxidative damage generated exogenously by using hydrogen peroxide in the Human Dermal Fibroblasts adult (HDFa) cell line as well as to their antimicrobial activity against the bacteria (Bacillus subtilis, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis). The relationship between physicochemical and biological properties of the complexes was discussed.

  11. Trends in lipoplex physical properties dependent on cationic lipid structure, vehicle and complexation procedure do not correlate with biological activity.

    PubMed

    Ferrari, M E; Rusalov, D; Enas, J; Wheeler, C J

    2001-04-01

    Using a group of structurally related cytofectins, the effects of different vehicle constituents and mixing techniques on the physical properties and biological activity of lipoplexes were systematically examined. Physical properties were examined using a combination of dye accessibility assays, centrifugation, gel electrophoresis and dynamic light scattering. Biological activity was examined using in vitro transfection. Lipoplexes were formulated using two injection vehicles commonly used for in vivo delivery (PBS pH 7.2 and 0.9% saline), and a sodium phosphate vehicle previously shown to enhance the biological activity of naked pDNA and lipoplex formulations. Phosphate was found to be unique in its effect on lipoplexes. Specifically, the accessible pDNA in lipoplexes formulated with cytofectins containing a gamma-amine substitution in the headgroup was dependent on alkyl side chain length and sodium phosphate concentration, but the same effects were not observed when using cytofectins containing a beta-OH headgroup substitution. The physicochemical features of the phosphate anion, which give rise to this effect in gamma-amine cytofectins, were deduced using a series of phosphate analogs. The effects of the formulation vehicle on transfection were found to be cell type-dependent; however, of the formulation variables examined, the liposome/pDNA mixing method had the greatest effect on transgene expression in vitro. Thus, though predictive physical structure relationships involving the vehicle and cytofectin components of the lipoplex were uncovered, they did not extrapolate to trends in biological activity.

  12. Nanomechanical control of properties of biological membranes achieved by rodlike magnetic nanoparticles in a superlow-frequency magnetic field

    NASA Astrophysics Data System (ADS)

    Golovin, Yu. I.; Klyachko, N. L.; Gribanovskii, S. L.; Golovin, D. Yu.; Samodurov, A. A.; Majouga, A. G.; Sokolsky-Papkov, M.; Kabanov, A. V.

    2015-05-01

    It is proposed to use single-domain rodlike magnetic nanoparticles (MNPs) as mediators for nanomechanical control of properties of biological membranes and cells on the molecular or cellular level by exposing them to a homogeneous nonheating low-frequency magnetic field (AC MF). The trigger effect is achieved due to rotatory-oscillatory motion of MNPs in the AC MF, which causes the needed deformations in macromolecules of the membrane interacting with these MNPs.

  13. [Biological properties of Caski cell lines induced by exposing to the space environment].

    PubMed

    Yang, Cheng; Li, Guan-cheng; Li, Yue-hui; Hu, Jin-yue; Xiao, Yan; Zhang, Zhi-jie

    2007-06-01

    To investigate the biological properties of Caski cell lines induced by exposing to the space environment. Caski cells were carried in "Shen Zhou IV" airship. After 7 days of spaceflight, cells survived and were monocoloned, and the experimental methods such as cell morphological observation, the cell proliferation assay, flow cytometry cell cycle analysis, the soft agar assay, and tumorigenesis assay were used to analyze cell growth characteristics and malignant phenotypes. Altogether 1440 strains subclonal cell lines were established and 4 strains were screened. Compared with the control group, mutated cells appeared to have multiple cell morphological changes. Strains numbered 44F10 and 17E3 were screened due to their increased cell proliferation and tumorigenesis, and their cell cycles were induced to progress from G(1) to S phase, while strains 48A9 and 31F2 were opposite to 44F10 and 17E3 in cytological events. The average population double time of ground nomal control group, ground simulant control group, strains numbered 44F10, 17E3, 48A9 and 31F2 groups were 56.54, 58.44, 52.96, 51.46, 101.76 and 88.47h, respectively; compared with the control group, the average double time of strains numbered 44F10 and 17E3 was decline, but with no statistical significance. However, compared with the control groups, the average double time of 48A9 and 31F2 was significant increased (P<0.05). The colony formation rates were 9.7%, 9.3%, 14.7%, 12.1%, 0 and 0.1%, respectively, and the difference between the ground control groups and the other groups was significant (P<0.01); 6 groups of above-mentioned Caski cells were inoculated subcutaneously in Babl/c nude mice respectively. Forty-seven days later, the formed tumors in the nude mice were statistically analyzed and tested. The average weight of tumors of the above-mentioned groups was 0.066, 0.066, 0.175, 0.249, 0.011 and 0.018g. The difference between the ground control groups and other groups was significant (P<0

  14. Changes in the ecological properties of organic wastes during their biological treatment.

    PubMed

    Kuryntseva, P; Galitskaya, P; Selivanovskaya, S

    2016-12-01

    Organic wastes, such as the organic fractions of municipal solid waste (OFMSW) or sewage sludge (SS), have become a serious environmental problem in Russia as well as in other countries. The use of these wastes as soil amendments allows their negative impact on the environment to be minimized. However, before these wastes can be used, they need to be treated appropriately in order to decrease their level of hazard. In this study, composting of raw SS, OFMSW, a mixture of these two wastes (OFMSW+SS) at a ratio 1:2 as well as the anaerobically digested variants of these wastes (SSd, OFMSWd and OFMSWd+SSd) mixed with oiled sawdust was performed. Composting was conducted in the containers containing 20kg of the wastes. The results of three elutriate bioassays (with water flea Daphnia magna, infusoria Paramecium caudatum and radish plant, Raphanus sativus) and one contact bioassay (with oat plant Avena sativa) were used to indirectly estimate changes in the hazardous properties of the biological treatments. Besides, Corg, Ntot content and pH were analyzed in the process of composting. Within the study stability tests to determine maturation process completion were not carried out. It was revealed, that in the process of anaerobic pretreatment for 15days, the toxicity increased by a mean of 1.3-, 1.9- and 1.1-fold for OFMSW, SS and OFMSW+SS, respectively. During composting, the toxicity level of these pretreated samples decreased more rapidly as compared with those which were not pretreated. As a result, the toxicity levels of the elutriates from the final composts made of pretreated wastes OFMSW, SS and OFMSW+SS were three-, two- and 17-fold lower for D. magna and 15-, 21- and 12-fold lower for P. caudatum. As follows from phytotoxicity estimations, composts from digested substrates became mature on the 60th day and had a stimulation effect on the plants after the 90th day of incubation. For the composts prepared from raw substrates, a significantly longer period was

  15. Bioactive components and functional properties of biologically activated cereal grains: A bibliographic review.

    PubMed

    Singh, Arashdeep; Sharma, Savita

    2017-09-22

    Whole grains provide energy, nutrients, fibers, and bioactive compounds that may synergistically contribute to their protective effects. A wide range of these compounds is affected by germination. While some compounds, such as β-glucans are degraded, others, like antioxidants and total phenolics are increased by means of biological activation of grains. The water and oil absorption capacity as well as emulsion and foaming capacity of biologically activated grains are also improved. Application of biological activation of grains is of emerging interest, which may significantly enhance the nutritional, functional, and bioactive content of grains, as well as improve palatability of grain foods in a natural way. Therefore, biological activation of cereals can be a way to produce food grains enriched with health-promoting compounds and enhanced functional attributes.

  16. Near infrared spectra are more sensitive to land use changes than physical, chemical and biological soil properties

    NASA Astrophysics Data System (ADS)

    Guerrero, C.; Zornoza, R.; Mataix-Solera, J.; Mataix-Beneyto, J.; Scow, K.

    2009-04-01

    We studied the sensibility of the near infrared spectra (NIR) of soils to the changes caused by land use, and we compared with the sensibility of different sets of physical, chemical and biological soil properties. For this purpose, we selected three land uses, constituted by forest, almond trees orchards, and orchards abandoned between 10 and 15 years previously to sampling. Sampling was carried out in four different locations from the province of Alicante (SE Spain). We used discriminant analysis (DA) using different sets of soil properties. The different sets tested in this study using DA were: (1) physical and chemical properties (organic carbon, total nitrogen, available phosphorus, pH, electrical conductivity, cation exchange capacity, aggregate stability, water holding capacity, and available Ca, Mg, K and Na), (2) biochemical properties (microbial biomass carbon, basal respiration and urease, phosphatase and β-glucosidase activities), (3) phospholipids fatty acids (PLFAs), (4) physical, chemical and biochemical properties (all properties of the previous sets), and (5) the NIR spectra of soils (scores of the principal components). In general, all sets of properties were sensible to land use. This was observed in the DAs by the separation (more or less clear) of samples in groups defined by land use (irrespective of site). The worst results were obtained using soil physical and chemical properties. The combination of physical, chemical and biological properties enhanced the separation of samples in groups, indicating higher sensibility. It is accepted than combination of properties of different nature is more effective to evaluate the soil quality. The microbial community structure (PLFAs) was highly sensible to the land use, grouping correctly the 100% of the samples according with the land use. The NIR spectra were also sensitive to land use. The scores of the first 5 components, which explained 99.97% of the variance, grouped correctly the 85% of the soil

  17. Biological properties of coral GFP-type proteins provide clues for engineering novel optical probes and biosensors

    NASA Astrophysics Data System (ADS)

    Salih, Anya; Larkum, Anthony W.; Cronin, Thomas W.; Wiedenmann, Joerg; Szymczak, Ron; Cox, Guy C.

    2004-06-01

    In recent years, a variety of Green Fluorescent Protein (GFP)-like pigments have been discovered from corals and other marine organisms. They are widely used to expand the range of available GFP-type proteins in imaging applications, such as in vivo markers for gene expression and protein localization studies, FRET-based (Förster resonance energy transfer) multicolor imaging and biosensors. They have known diverse optical and biochemical properties but their in vivo spectral properties and biological function in marine organisms is only beginning to be understood. We have investigated their spectral diversity, optical properties and cellular microstructure in corals of the Great Barrier Reef with the aim of elucidating their photo-biological function/s as well as to identify novel proteins suitable for GFP-based technologies. We found numerous spectral variants, with emissions covering almost the full range of the visible spectrum. Many of these GFP-like proteins, especially in corals from the more extreme habitats, such as sun-exposed shallows or in deep water, showed a range of light-related spectral characteristics: high photostability, spectral tuning for energy transfer and dynamic photo-induced transformation properties. Intra-cellularly they were organized into spectral donor-acceptor pairs or even arrays, tuned for FRET. Coral color proteins thus offer an exciting potential to expand the use of the available GFPs in bio-imaging applications and as a basis for improved protein engineering.

  18. Characterizing and optimizing human anticancer drug targets based on topological properties in the context of biological pathways.

    PubMed

    Zhang, Jian; Wang, Yan; Shang, Desi; Yu, Fulong; Liu, Wei; Zhang, Yan; Feng, Chenchen; Wang, Qiuyu; Xu, Yanjun; Liu, Yuejuan; Bai, Xuefeng; Li, Xuecang; Li, Chunquan

    2015-04-01

    One of the challenging problems in drug discovery is to identify the novel targets for drugs. Most of the traditional methods for drug targets optimization focused on identifying the particular families of "druggable targets", but ignored their topological properties based on the biological pathways. In this study, we characterized the topological properties of human anticancer drug targets (ADTs) in the context of biological pathways. We found that the ADTs tended to present the following seven topological properties: influence the number of the pathways related to cancer, be localized at the start or end of the pathways, interact with cancer related genes, exhibit higher connectivity, vulnerability, betweenness, and closeness than other genes. We first ranked ADTs based on their topological property values respectively, then fused them into one global-rank using the joint cumulative distribution of an N-dimensional order statistic to optimize human ADTs. We applied the optimization method to 13 anticancer drugs, respectively. Results demonstrated that over 70% of known ADTs were ranked in the top 20%. Furthermore, the performance for mercaptopurine was significant: 6 known targets (ADSL, GMPR2, GMPR, HPRT1, AMPD3, AMPD2) were ranked in the top 15 and other four out of the top 15 (MAT2A, CDKN1A, AREG, JUN) have the potentialities to become new targets for cancer therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Mobility as an emergent property of biological organization: Insights from experimental evolution.

    PubMed

    Wallace, Ian J; Garland, Theodore

    2016-05-06

    Anthropologists accept that mobility is a critical dimension of human culture, one that links economy, technology, and social relations. Less often acknowledged is that mobility depends on complex and dynamic interactions between multiple levels of our biological organization, including anatomy, physiology, neurobiology, and genetics. Here, we describe a novel experimental approach to examining the biological foundations of mobility, using mice from a long-term artificial selection experiment for high levels of voluntary exercise on wheels. In this experiment, mice from selectively bred lines have evolved to run roughly three times as far per day as those from nonselected control lines. We consider three insights gleaned from this experiment as foundational principles for the study of mobility from the perspective of biological evolution. First, an evolutionary change in mobility will necessarily be associated with alterations in biological traits both directly and indirectly connected to mobility. Second, changing mobility will result in trade-offs and constraints among some of the affected traits. Third, multiple solutions exist to altering mobility, so that various combinations of adjustments to traits linked with mobility can achieve the same overall behavioral outcome. We suggest that anthropological knowledge of variation in human mobility might be improved by greater research attention to its biological dimensions.

  20. [Study on influence between activated carbon property and immobilized biological activated carbon purification effect].

    PubMed

    Wang, Guang-zhi; Li, Wei-guang; He, Wen-jie; Han, Hong-da; Ding, Chi; Ma, Xiao-na; Qu, Yan-ming

    2006-10-01

    By means of immobilizing five kinds of activated carbon, we studied the influence between the chief activated carbon property items and immobilized bioactivated carbon (IBAC) purification effect with the correlation analysis. The result shows that the activated carbon property items which the correlation coefficient is up 0.7 include molasses, abrasion number, hardness, tannin, uniform coefficient, mean particle diameter and effective particle diameter; the activated carbon property items which the correlation coefficient is up 0.5 include pH, iodine, butane and tetrachloride. In succession, the partial correlation analysis shows that activated carbon property items mostly influencing on IBAC purification effect include molasses, hardness, abrasion number, uniform coefficient, mean particle diameter and effective particle diameter. The causation of these property items bringing influence on IBAC purification is that the activated carbon holes distribution (representative activated carbon property item is molasses) provides inhabitable location and adjust food for the dominance bacteria; the mechanical resist-crash property of activated carbon (representative activated carbon property items: abrasion number and hardness) have influence on the stability of biofilm; and the particle diameter size and distribution of activated carbon (representative activated carbon property items: uniform coefficient, mean particle diameter and effective particle diameter) can directly affect the force of water in IBAC filter bed, which brings influence on the dominance bacteria immobilizing on activated carbon.

  1. The effect of model soil contamination with Cr, Cu, Ni, and Pb on the biological properties of soils in the dry steppe and semidesert regions of southern Russia

    NASA Astrophysics Data System (ADS)

    Kolesnikov, S. I.; Spivakova, N. A.; Kazeev, K. Sh.

    2011-09-01

    Model soil contamination with Cr, Cu, Ni, and Pb in the dry steppes and semideserts of southern Russia has worsened the biological soil properties. With respect to the degree of deterioration of the biological properties, the soils can be arranged in the following sequence: dark chestnut soils > chestnut soils > light chestnut soils > brown semidesert soils > sandy brown semidesert soils. The sequence of metal oxides according to the adverse effect on the biological soil properties is as follows: CrO3 > CuO ≥ PbO ≥ NiO.

  2. Interaction of silver nanoparticles with biological objects: antimicrobial properties and toxicity for the other living organisms

    NASA Astrophysics Data System (ADS)

    Egorova, E. M.

    2011-04-01

    This paper presents several examples of the biological effects of small-sized silver nanoparticles (10.5±3.5nm) observed in experiments on bacteria, slim mold, unicellular alga and plant seeds. The nanoparticles were prepared by the biochemical synthesis, based on the reduction of metal ions in reverse vicelles by biological reductants - natural plant pigments (flavonoids). It is found that, except for the plant seeds, silver nanoparticles (SNP) act as a strong toxic agent, both in water solution and as part of liquid-phase material. It is shown also that the biological action of silver nanoparticles can not be reduced to the toxic action of silver ions in equivalent concentrations or to that of the surfactant (the SNP stabilizer) present in the SNP water solution. Possible SNP applications are suggested.

  3. Optical properties of peritoneal biological tissues in the spectral range of 350-2500 nm

    NASA Astrophysics Data System (ADS)

    Bashkatov, A. N.; Genina, E. A.; Kozintseva, M. D.; Kochubei, V. I.; Gorodkov, S. Yu.; Tuchin, V. V.

    2016-01-01

    The optical characteristics of biological tissues sampled from the anterior abdominal wall of laboratory rats are for the first time experimentally studied in a wide wavelength range (350-2500 nm). The experiments have been performed in vitro using a LAMBDA 950 (PerkinElmer, United States) spectrophotometer. Inverse Monte Carlo simulation is used to restore the spectral dependences for scattering and absorption coefficients, as well as the scattering anisotropy factor for biological tissue based on the recorded spectra of diffuse reflection and total and collimated transmissions.

  4. The effect of magnesium sulphate on the photochemical formation of microstructures with properties of biological order.

    PubMed

    Bahadur, K; Ranganayaki, S; Maurya, H K

    1979-01-01

    The photochemical formation of microstructures in 1:2:1:1 mixture of ammonium molybdate, diammonium hydrogen phosphate, biological minerals, and formaldehyde showed better results at 9.6 x 10(-5) M concentration of magnesium sulphate in the mixture. The number of particles decreases with increasing concentration of magnesium sulphate.

  5. Biological properties of solid free form designed ceramic scaffolds with BMP-2: in vitro and in vivo evaluation.

    PubMed

    Abarrategi, Ander; Moreno-Vicente, Carolina; Martínez-Vázquez, Francisco Javier; Civantos, Ana; Ramos, Viviana; Sanz-Casado, José Vicente; Martínez-Corriá, Ramón; Perera, Fidel Hugo; Mulero, Francisca; Miranda, Pedro; López-Lacomba, José Luís

    2012-01-01

    Porous ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. Solid free form (SFF) fabrication methods allow fabrication of ceramic scaffolds with fully controlled pore architecture, which opens new perspectives in bone tissue regeneration materials. However, little experimentation has been performed about real biological properties and possible applications of SFF designed 3D ceramic scaffolds. Thus, here the biological properties of a specific SFF scaffold are evaluated first, both in vitro and in vivo, and later scaffolds are also implanted in pig maxillary defect, which is a model for a possible application in maxillofacial surgery. In vitro results show good biocompatibility of the scaffolds, promoting cell ingrowth. In vivo results indicate that material on its own conducts surrounding tissue and allow cell ingrowth, thanks to the designed pore size. Additional osteoinductive properties were obtained with BMP-2, which was loaded on scaffolds, and optimal bone formation was observed in pig implantation model. Collectively, data show that SFF scaffolds have real application possibilities for bone tissue engineering purposes, with the main advantage of being fully customizable 3D structures.

  6. Biological Properties of Solid Free Form Designed Ceramic Scaffolds with BMP-2: In Vitro and In Vivo Evaluation

    PubMed Central

    Abarrategi, Ander; Moreno-Vicente, Carolina; Martínez-Vázquez, Francisco Javier; Civantos, Ana; Ramos, Viviana; Sanz-Casado, José Vicente; Martínez-Corriá, Ramón; Perera, Fidel Hugo; Mulero, Francisca; Miranda, Pedro; López-Lacomba, José Luís

    2012-01-01

    Porous ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. Solid free form (SFF) fabrication methods allow fabrication of ceramic scaffolds with fully controlled pore architecture, which opens new perspectives in bone tissue regeneration materials. However, little experimentation has been performed about real biological properties and possible applications of SFF designed 3D ceramic scaffolds. Thus, here the biological properties of a specific SFF scaffold are evaluated first, both in vitro and in vivo, and later scaffolds are also implanted in pig maxillary defect, which is a model for a possible application in maxillofacial surgery. In vitro results show good biocompatibility of the scaffolds, promoting cell ingrowth. In vivo results indicate that material on its own conducts surrounding tissue and allow cell ingrowth, thanks to the designed pore size. Additional osteoinductive properties were obtained with BMP-2, which was loaded on scaffolds, and optimal bone formation was observed in pig implantation model. Collectively, data show that SFF scaffolds have real application possibilities for bone tissue engineering purposes, with the main advantage of being fully customizable 3D structures. PMID:22470527

  7. A Critical Review of Properties and Analytical Methods for the Determination of Oxytetracyline in Biological and Pharmaceutical Matrices.

    PubMed

    Sversut, Rúbia Adrieli; da Silva, Adriane Andrade; Cardoso, Teófilo Fernando Mazon; Kassab, Nájla Mohamad; do Amaral, Marcos Serrou; Salgado, Hérida Regina Nunes

    2017-03-04

    Antibiotics have an unquestionable importance in the treatment of many infections. Oxytetracycline is an antibiotic belonging to the class of tetracyclines, available for use in human and veterinary medicine. Development of analytical methods that prove the quality and efficacy of these drugs is fundamentally important to the pharmaceutical industry. In this context, the research presents an overview of the analytical profile of oxytetracycline, describing its chemical and pharmacological properties, and analytical methods for quantification of this drug in biological samples and pharmaceutical products. Oxytetracycline can be analyzed in these matrices by many types of methodologies. However, high-performance liquid chromatography is the most widely used, being recommended by official compendia. This kind of study can be useful to support the development of new efficient and sustainable analytical methods that may be utilized in the quality control routine of oxytetracycline in pharmaceutical products and pharmacokinetic monitoring in biological samples.

  8. Conformational and biological properties of the Ala10 analogue of human des-Trp1,Nle12-minigastrin.

    PubMed

    Mammi, S; Foffani, M T; Peggion, E; Galleyrand, J C; Bali, J P; Simonetti, M; Göhring, W; Moroder, L; Wünsch, E

    1989-09-05

    Synthesis, conformation, and biological properties of the Ala10 analogue of des-Trp1,Nle12-minigastrin are reported. Replacement of the Gly residue in the original sequence with Ala remarkably changes the conformational preference of the hormone in trifluoroethanol. CD and NMR results indicate that the conformational change is mainly located in the C-terminal portion of the molecule, with probable extension of the N-terminal alpha-helix throughout the entire sequence. The structural modification causes a 10-fold decrease in the biological potency of the hormone, which is about as active as the C-terminal tetrapeptide amide. These findings support our previous hypothesis that the optimal bioactive conformation of the native hormone is U-shaped, with mutual interactions among the two end segments.

  9. Changes in physicochemical and biological properties of porcine bone derived hydroxyapatite induced by the incorporation of fluoride

    PubMed Central

    Qiao, Wei; Liu, Quan; Li, Zhipeng; Zhang, Hanqing; Chen, Zhuofan

    2017-01-01

    Abstract As the main inorganic component of xenogenic bone graft material, bone-derived biological apatite (BAp) has been widely used in implant dentistry, oral and maxillofacial surgery and orthopedics. However, BAp produced via calcination of animal bones still suffers from some drawbacks, such as insufficient mechanical strength and inadequate degradation rate, which impede its application. Fluoride is known to play important roles in both physiological and pathological processes of human hard tissues for its double effects on bones and teeth. In order to understand the effects of fluoride on the properties of BAp, as well as the mechanism behind them, porcine bone derived hydroxyapatite (PHAp) was prepared via thermal treatment, which was then fluoride incorporated at a series concentrations of sodium fluoride, and noted as 0.25-FPHAp, 0.50-FPHAp, and 0.75-FPHAp respectively. The physicochemical characteristics of the materials, including crystal morphology, crystallinity, functional groups, elemental composition, compressive strength, porosity and solubility, were then determined. The biological properties, such as protein adsorption and cell attachment, were also evaluated. It was found that the spheroid-like crystals of PHAp were changed into rod-like after fluoride substitution, resulting in a fluoride concentration-dependent increase in compressive strength, as well as a decreased porosity and solubility of the apatite. However, even though the addition of fluoride was demonstrated to enhance protein adsorption and cell attachment of the materials, the most favorable results were intriguingly achieved in FPHAp with the least fluoride content. Collectively, low level of fluoride incorporation is proposed promising for the modification of clinically used BAp based bone substitute materials, because of its being able to maintain a good balance between physicochemical and biological properties of the apatite. PMID:28243337

  10. TH-A-19A-05: Modeling Physics Properties and Biologic Effects Induced by Proton and Helium Ions

    SciTech Connect

    Taleei, R; Titt, U; Peeler, C; Guan, F; Mirkovic, D; Grosshans, D; Mohan, R

    2014-06-15

    Purpose: Currently, proton and carbon ions are used for cancer treatment. More recently, other light ions including helium ions have shown interesting physical and biological properties. The purpose of this work is to study the biological and physical properties of helium ions (He-3) in comparison to protons. Methods: Monte Carlo simulations with FLUKA, GEANT4 and MCNPX were used to calculate proton and He-3 dose distributions in water phantoms. The energy spectra of proton and He-3 beams were calculated with high resolution for use in biological models. The repair-misrepairfixation (RMF) model was subsequently used to calculate the RBE. Results: The proton Bragg curve calculations show good agreement between the three general purpose Monte Carlo codes. In contrast, the He-3 Bragg curve calculations show disagreement (for the magnitude of the Bragg peak) between FLUKA and the other two Monte Carlo codes. The differences in the magnitude of the Bragg peak are mainly due to the discrepancy in the secondary fragmentation cross sections used by the codes. The RBE for V79 cell lines is about 0.96 and 0.98 at the entrance of proton and He-3 ions depth dose respectively. The RBE increases to 1.06 and 1.59 at the Bragg peak of proton and He-3 ions. The results demonstrated that LET, microdosimetric parameters (such as dose-mean lineal energy) and RBE are nearly constant along the plateau region of Bragg curve, while all parameters increase within the Bragg peak and at the distal edge for both proton and He-3 ions. Conclusion: The Monte Carlo codes should revise the fragmentation cross sections to more accurately simulate the physical properties of He-3 ions. The increase in RBE for He-3 ions is higher than for proton beams at the Bragg peak.

  11. Characterization of Mechanical and Biological Properties of 3-D Scaffolds Reinforced with Zinc Oxide for Bone Tissue Engineering

    PubMed Central

    Shuai, Cijun; Peng, Shuping

    2014-01-01

    A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP) scaffolds via selective laser sintering (SLS). We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO). Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam1/2, and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF), indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially. PMID:24498185

  12. Characterization of mechanical and biological properties of 3-D scaffolds reinforced with zinc oxide for bone tissue engineering.

    PubMed

    Feng, Pei; Wei, Pingpin; Shuai, Cijun; Peng, Shuping

    2014-01-01

    A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP) scaffolds via selective laser sintering (SLS). We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO). Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam(1/2), and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF), indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially.

  13. Ti–Ag–Pd alloy with good mechanical properties and high potential for biological applications

    PubMed Central

    Zadorozhnyy, V. Yu.; Shi, X.; Gorshenkov, M. V.; Kozak, D. S.; Wada, T.; Louzguine-Luzgin, D. V.; Inoue, A.; Kato, H.

    2016-01-01

    Ti-based alloys containing Ag were produced by tilt-casting method and their properties were studied. Even in its as-cast state, Ti94Ag3Pd3 showed relatively high tensile properties, good electrochemical behavior, and good biocompatibility. The relatively good mechanical properties of the as-cast α-Ti-type Ti94Ag3Pd3 alloy (tensile strength up to 850 MPa and elongation of ~10%) can be explained by its severely deformed, fine crystalline structure. The high biocompatibility of Ti94Ag3Pd3 can be explained by the Ag–Pd interaction, which inhibits the release of Ag ions from the surface. Ag, in combination with Pd has no toxic effects and demonstrates useful antimicrobial properties. The Ti94Ag3Pd3 alloy shows a good potential to be applied as a biomedical implant alloy. PMID:27122177

  14. On alterations in the refractive index and scattering properties of biological tissue caused by histological processing

    NASA Astrophysics Data System (ADS)

    Aung, Htet; DeAngelo, Bianca; Soldano, John; Kostyk, Piotr; Rodriguez, Braulio; Xu, M.

    2013-02-01

    Clinical tissue processing such as formalin fixing, paraffin-embedding and histological staining alters significantly the optical properties of the tissue. We document the alterations in the optical properties of prostate cancer tissue specimens in the 500nm to 700nm spectral range caused by histological processing with quantitative differential interference contrast (qDIC) microscopy. A simple model to explain these alterations is presented at the end.

  15. Biological and Molecular Properties of Dengue 2 Strains Isolated during the DHF/DSS Cuban Epidemic, 1981

    PubMed Central

    González, Lester; Álvarez, Mayling; del Rosario, Delfina; Pavón, Alequis; Prado, Irina; Díaz, Joel; Morier, Luis; Guzmán, María G.

    2007-01-01

    To study some biological and molecular properties of nine DENV-2 strains isolated during the 1981 Cuban epidemic, temperature sensitivity, viral plaque size, the kinetic of virus replication in newborn mice inoculated by intracerebral route, the influence of pH medium on virus-cell attachment phase and the restriction enzyme pattern were studied. Strains were classified in two patterns according to temperature sensitivity, plaque size, and virus replication in mouse brain and cell culture and restriction enzymatic pattern the changes observed differentiate clearly the strains isolated at the beginning and at the end of the epidemic suggesting that viruses with different characteristics circulated. PMID:23675036

  16. Microplatforms for gradient field generation of various properties and biological applications.

    PubMed

    Kim, Sung-Hwan; Lee, Gi-Hun; Park, Joong Yull; Lee, Sang-Hoon

    2015-04-01

    Well-designed microfluidic platforms can be excellent tools to eliminate bottleneck problems or issues that have arisen in biological fields by providing unprecedented high-resolution control of mechanical and chemical microenvironments for cell culture. Among such microtechnologies, the precise generation of biochemical concentration gradients has been highly regarded in the biorelated scientific fields; even today, the principles and mechanisms for gradient generation continue to be refined, and the number of applications for this technique is growing. Here, we review the current status of the concentration gradient generation technologies achieved in various microplatforms and how they have been and will be applied to biological issues, particularly those that have arisen from cancer research, stem cell research, and tissue engineering. We also provide information about the advances and future challenges in the technological aspects of microscale concentration gradient generation.

  17. Biological control of crystal texture: a widespread strategy for adapting crystal properties to function.

    PubMed

    Berman, A; Hanson, J; Leiserowitz, L; Koetzle, T F; Weiner, S; Addadi, L

    1993-02-05

    Textures of calcite crystals from a variety of mineralized tissues belonging to organisms from four phyla were examined with high-resolution synchrotron x-ray radiation. Significant differences in coherence length and angular spread were observed between taxonomic groups. Crystals from polycrystalline skeletal ensembles were more perfect than those that function as single-crystal elements. Different anisotropic effects on crystal texture were observed for sea urchin and mollusk calcite crystals, whereas none was found for the foraminifer, Patellina, and the control calcite crystals. These results show that the manipulation of crystal texture in different organisms is under biological control and that crystal textures in some tissues are adapted to function. A better understanding of this apparently widespread biological phenomenon may provide new insights for improving synthetic crystal-containing materials.

  18. Bio-nano interface: The impact of biological environment on nanomaterials and their delivery properties.

    PubMed

    Cai, Kaimin; Wang, Andrew Z; Yin, Lichen; Cheng, Jianjun

    2017-10-10

    The past several decades have witnessed the rapid development of nanomedicine (NM) which integrates the advancement of various interdisciplinary areas of science, engineering, and medicine. While a few clinical successes of NM greatly change the landscape of disease diagnosis and treatment, there are several areas of NM remaining to be explored. One such area is the complicated interactions between the NM and biological environment post administration, and how such interaction affects the biological performance of NM. Here, we review the recent progresses on this topic and discuss the interaction of NM with microscopic biomolecules, cells, and the macroscopic in vivo environment. The complete profiling of the bio/nanomaterials interface and interaction should have profound impact on the optimization and de novo design of new NM with better in vivo performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Biological control of crystal texture: A widespread strategy for adapting crystal properties to function

    SciTech Connect

    Berman, A.; Leiserowitz, L.; Weiner, S.; Addadi, L. ); Hanson, J.; Koetzle, T.F. )

    1993-02-05

    Textures of calcite crystals from a variety of mineralized tissues belong to organisms from four phyla were examined with high-resolution synchrotron x-ray radiation. Significant differences in coherence length and angular spread were observed between taxonomic groups. Crystals from polycrystalline skeletal ensembles were more perfect than those that function as single-crystal elements. Different anistropic effects on crystal texture were observed for sea urchin and mollusk calcite crystals, whereas none was found for the foraminifer, Patellina, and the control calcite crystals. These results show that the manipulation of crystal texture in different organisms is under biological control and that crystal textures in some tissues are adapted to function. A better understanding of this apparently widespread biological phenomenon may provide new insights for improving synthetic crystal-containing materials. 18 refs., 3 figs., 1 tab.

  20. Biological and biochemical properties of the carbon composite and polyethylene implant materials.

    PubMed

    Pesáková, V; Smetana, K; Balík, K; Hruska, J; Petrtýl, M; Hulejová, H; Adam, M

    2003-06-01

    We studied the biocompatibility of the carbon composites and polyethylene materials with and without collagen or collagen and proteoglycan cover. We used the in vitro technology to study the adhesion of model cells evalution, their metabolic activity and the production of TNF-alpha as a cytokine model. Under in vivo condition, the biocompatibility of tested polymers were studied in the implantation experiment, subcutaneously in the interscapular region in the laboratory rat. We have found in the in vitro assay favorable proliferation and the smallest production of pro-inflammatory TNF-alpha cytokine in cells adherent to the hydrophobic polyethylene material coated with biological macromolecules. Using in vivo tests performed by the implantation of materials to the rat we demonstrated that the materials are not cytotoxic. The tissue capsule surrounding the implants was not significantly influenced by the type of the implant and the pre-treatment by the biological molecules. However, the foreign-body giant multinucleated cells were observed only in the vicinity of the collagen - covered hydrophobic polyethylene implant. Interestingly, while the collagen coating improved the biocompatibility of tested polymers in vitro, the inflammatory reaction against this covered materials was higher under in vivo conditions. The pre-treatment of carbon composites by both types of biological macromolecules reduced the occurrence of carbon debris in the implantation site. The tested carbon composites and polyethylene materials are not toxic. The pre-treatment of the materials by extracellular matrix components increased their biological tolerance in vitro and reduced implant wears in animal experiment, which can be important for the medical application.

  1. Metabolic products of microorganisms. 239. Bacimethrin isolated from Streptomyces albus identification, derivatives, synthesis and biological properties.

    PubMed

    Drautz, H; Messerer, W; Zähner, H; Breiding-Mack, S; Zeeck, A

    1987-10-01

    Bacimethrin (1), known as a thiamine antagonist produced by Bacillus megatherium, was isolated from Streptomyces albus and has been further characterized by NMR spectra and acetylation. A new easy three step synthesis for 1 is described. The biological activity of 1, and its mode of action were discussed. There are indications that bacimethrin inhibits the phosphorylation of 4-amino-5-hydroxymethyl-2-methylpyrimidine (Pyr-OH) during thiamine biosynthesis.

  2. Composting of the solid fraction of digestate derived from pig slurry: Biological processes and compost properties

    SciTech Connect

    Tambone, Fulvia Terruzzi, Laura; Scaglia, Barbara; Adani, Fabrizio

    2015-01-15

    Highlights: • Anaerobic digestion leads to the production of a biologically stable digestate. • Solid–liquid separation produces a solid fraction having high fertilizer value. • Composting process shows low biological activity due to high biological stability of digestate. • Solid digestate fraction can be composted in a short time or used directly as organic fertilizer. - Abstract: The aim of this paper was to assess the characteristics of the solid fractions (SF) obtained by mechanical separation of digestate, their compostability and compost quality. To do so, the SF of digestates obtained from anaerobic digestion of pig slurry, energy crops and agro-industrial residues were sampled in five plants located in Northern Italy. Results obtained indicated that anaerobic digestion by itself promoted the high biological stability of biomasses with a Potential Dynamic Respiration Index (PDRI) close to 1000 mgO{sub 2} kg V S{sup −1} h{sup −1}. Subsequent composting of digestates, with an added bulking agent, did not give remarkably different results, and led only to a slight modification of the characteristics of the initial non-composted mixtures; the composts obtained fully respected the legal limits for high quality compost. Chemical studies of organic matter composition of the biomasses by using CP MAS {sup 13}C NMR, indicated that the compost was composed of a high relative content of O-alkyl-C (71.47% of total C) (cellulose and hemicelluloses) and a low alkyl-C (12.42%) (i.e. volatile fatty acids, steroid-like molecules, aliphatic biopolymers and proteins)

  3. Some emerging principles underlying the physical properties, biological actions, and utility of vitrification solutions.

    PubMed

    Fahy, G M; Levy, D I; Ali, S E

    1987-06-01

    Vitrification solutions are aqueous cryoprotectant solutions which do not freeze when cooled at moderate rates to very low temperatures. Vitrification solutions have been used with great success for the cryopreservation of some biological systems but have been less successful or unsuccessful with other systems, and more fundamental knowledge about vitrification solutions is required. The purpose of the present survey is to show that a general understanding of the physical behavior and biological effects of vitrification solutions, as well as an understanding of the conditions under which vitrification solutions are required, is gradually emerging. Detailed nonequilibrium phase diagram information in combination with specific information on the tolerance of biological systems to ice and to cryoprotectant at subzero temperatures provides a quantitative theoretical basis for choosing between vitrification and freezing. The vitrification behavior of mixtures of cryoprotective agents during cooling is predictable from the behavior of the individual agents, and the behavior of individual agents is gradually becoming predictable from the details of their molecular structures. Progress is continuing concerning the elucidation of mechanisms and cellular sites of toxicity and mechanisms for the reduction of toxicity. Finally, important new information is rapidly emerging concerning the crystallization of previously vitrified cryoprotectant solutions during warming. It appears that vitrification tendency, toxicity, and devitrification all depend on subtle variations in the organization of water around dissolved substances.

  4. Effect of capping agents: Structural, optical and biological properties of ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Javed, Rabia; Usman, Muhammad; Tabassum, Saira; Zia, Muhammad

    2016-11-01

    Different biological activities of capped and uncapped ZnO nanoparticles were investigated, and the effects of potential capping agents on these biological activities were studied. ZnO nanoparticles were synthesized and capped by polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) using a simple chemical method of co-precipitation. Characterization by X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR) and UV-vis spectroscopy confirmed the crystallinity, size, functional group, and band gap of synthesized nanoparticles. Reduction in size occurred from 34 nm to 26 nm due to surfactant. Results of all biological activities indicated significantly higher values in capped as compared to uncapped nanoparticles. Antibacterial activity against Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633), Escherichia coli (ATCC15224), and Acetobacter was obtained. This activity was more prominent against Gram-positive bacteria, and ZnO-PVP nanoparticles elucidated highest antibacterial activity (zone of inhibition 17 mm) against Gram-positive, Bacillus subtilis species. Antioxidant activities including total flavonoid content, total phenolic content, total antioxidant capacity, total reducing power and %age inhibition of DPPH, and antidiabetic activity against α-amylase enzyme found to be exhibited highest by ZnO-PEG nanoparticles.

  5. Effectiveness and properties of the biological prosthesis Permacol™ in pediatric surgery: A large single center experience.

    PubMed

    Filisetti, Claudia; Costanzo, Sara; Marinoni, Federica; Vella, Claudio; Klercy, Catherine; Riccipetitoni, Giovanna

    2016-05-01

    The use of prosthetic patches of non-absorbable materials represents a valid tool in the treatment of abdominal wall and diaphragmatic defects in pediatric age. In recent years research has developed biological dermal scaffolds made from a sheet of acellular matrix that can provide the desired support and reduce the occurrence of complications from non-absorbable implant. We present our experience and a systematic review to evaluate the use of biologic prosthesis for abdominal wall closure in pediatric patients. The study from January 2009 to January 2015 involved 20 patients treated with Permacol™ implant. We observed postoperative complications only in patients treated for abdominal wall closure, which is the major indication for the use of Permacol™. We conducted a systematic review and meta-analysis (according to PRISMA) on PubMed/Medline, Scopus and EMBASE regarding the use of biological prosthesis in pediatric population considering the incidence of complications as the primary outcome. 3/20 patients experienced complications: 2 patients with skin necrosis healed conservatively and 1 of them developed laparocele. Thus only 1 patient with incisional hernia had significant surgery complication. In patients who were permanently implanted with Permacol™ it has not determined adverse reactions with optimal functional outcome. In accordance with the few data (case reports and case series) reported in literature about pediatric patients, our experience in different pathologies and applications has shown the effectiveness of Permacol™, in particular for the non-occurrence of infections, that often affect the use of prosthesis.

  6. Mechanical and biological properties of the micro-/nano-grain functionally graded hydroxyapatite bioceramics for bone tissue engineering.

    PubMed

    Zhou, Changchun; Deng, Congying; Chen, Xuening; Zhao, Xiufen; Chen, Ying; Fan, Yujiang; Zhang, Xingdong

    2015-08-01

    Functionally graded materials (FGM) open the promising approach for bone tissue repair. In this study, a novel functionally graded hydroxyapatite (HA) bioceramic with micrograin and nanograin structure was fabricated. Its mechanical properties were tailored by composition of micrograin and nanograin. The dynamic mechanical analysis (DMA) indicated that the graded HA ceramics had similar mechanical property compared to natural bones. Their cytocompatibility was evaluated via fluorescent microscopy and MTT colorimetric assay. The viability and proliferation of rabbit bone marrow mesenchymal stem cells (BMSCs) on ceramics indicated that this functionally graded HA ceramic had better cytocompatibility than conventional HA ceramic. This study demonstrated that functionally graded HA ceramics create suitable structures to satisfy both the mechanical and biological requirements of bone tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Determination of structural, spectral, electronic and biological properties of tosufloxacin boron complexes and investigation of substituent effect

    NASA Astrophysics Data System (ADS)

    Sayin, Koray; Karakaş, Duran

    2017-10-01

    Quantum chemical calculations are performed over some boron complexes with tosufloxacin. Boron complex with fluorine atoms are optimized at HF/6-31+G(d), B3LYP/6-31+G(d) and M062X/6-31+G(d) level and the best level is determined by comparison of experimental and calculated results. The other complexes are optimized by using the best level. Structural properties, IR and NMR spectrum are examined in detail. Biological activities of mentioned complexes are investigated by some quantum chemical descriptors and molecular docking analyses. As results, it is found that boron complex with fluorine atoms coordinated to boron atom is the best candidate for anticancer drug. Additionally, NLO properties of mentioned complexes are investigated and complex (2) is found as the best candidate for NLO applications.

  8. Viscoelastic Properties of a Hierarchical Model of Soft Biological Tissue: Two-Dimensional and Three-Dimensional Cases

    NASA Astrophysics Data System (ADS)

    Posnansky, Oleg

    2016-09-01

    The measuring of viscoelastic response is widely used for revealing information about soft matter and biological tissue noninvasively. This information encodes intrinsic dynamic correlations and depends on relations between macroscopic viscoelasticity and structure at the mesoscopic scale. Here we show numerically that the frequency dependent dynamical shear moduli distinguish between the mesoscopic architectural complexities and sensitive to the Euclidean dimensionality. Our approach enables the explanation of two- and three-dimensional viscoelastic experiments by objectively choosing and modeling the most relevant architectural features such as the concentration of compounds and intra-model hierarchical characteristics of physical parameters. Current work provides a link between the macroscopical effective viscoelastic properties to viscoelastic constants and network geometry on the mesoscale. Besides of this we also pay attention to the analytical properties of generalized susceptibility function of considered constitutive model accounting principles of causality.

  9. Microstructural characterization and comparative evaluation of physical, mechanical and biological properties of three ceramics for metal-ceramic restorations.

    PubMed

    Kontonasaki, Eleana; Kantiranis, Nikolaos; Papadopoulou, Lambrini; Chatzistavrou, Xanthippi; Kavouras, Panagiotis; Zorba, Triantafillia; Sivropoulou, Afroditi; Chrissafis, Konstantinos; Paraskevopoulos, Konstantinos M; Koidis, Petros T

    2008-10-01

    A wide variety of dental ceramics compositions have been introduced in dental clinical practice in order to combine desired aesthetics with superior mechanical performance. The aim of the present study was to investigate the microstructural changes in three dental ceramics after their sintering according to manufacturers' instructions and to comparatively evaluate some of their physical, mechanical and biological properties. The analysis of the phases present in each material before and after sintering was performed with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD). The thermal properties of ceramic specimens were evaluated with differential thermal and thermogravimetric analysis (TG-DTA). The mechanical properties evaluated were fracture toughness, Young's modulus and microhardness with the Vickers indentation method. MTT assay was used for cell proliferation assessment. One-way analysis of variance (ANOVA) with Bonferroni multiple comparisons tests was used to determine statistically significant differences (significance level of p<0.05). Results showed a remarkable variation among the three ceramic compositions of leucite content in the starting unheated ceramic powders ranging between 14 and 32 wt.% and in the respective sintered powders ranging between 15 and 41 wt.% The low fusing glass-ceramic and the high fusing leucite-based ceramic presented significantly higher fracture toughness (p<0.001) and microhardness and lower modulus of elasticity (p<0.05) compared to the low fusing feldspathic ceramic. The three ceramics were almost equivalent concerning their in vitro biological behavior. Variations in crystal structure, distribution and composition are related to differences concerning mechanical properties of dental ceramics.

  10. New sol-gel bioactive glass and titania composites with enhanced physico-chemical and biological properties.

    PubMed

    Pawlik, Justyna; Widziołek, Magdalena; Cholewa-Kowalska, Katarzyna; Łączka, Maria; Osyczka, Anna Maria

    2014-07-01

    We developed TiO2 matrix composites modified by sol-gel bioactive glasses (SBG) of either high CaO content (A2) or high SiO2 content (S2). The latter were mixed with titanium dioxide (TiO2) at 75:25, 50:50, and 25:75 weight ratios and sintered at 1250°C for 2 h. We examined the effects of various types (A2 or S2) and compositional TiO2 :SBG ratios on the mechanical properties of resulting composites, their bioactivity and human bone marrow mesenchymal stem cells (MSC) response. The chemistry of SBGs influenced the phase composition, mechanical and biological properties of the composites. Rutile and titanite prevailed in A2-TiO2 composites, and rutile and crystobalite in S2-TiO2 composites. Compressive strength increased significantly for 25A2-TiO2 composites (140 MPa) compared to matrix TiO2 (58 MPa). Composites containing 50-75 wt % of either SBG displayed bioactive properties as determined by simulated body fluid test. Compared to TiO2, human bone marrow stromal cell (BMSC) viability was enhanced on the composites containing 25 wt % of either SBG, whereas the composites modified by 25 wt % of S2 enhanced alkaline phosphatase activity and mineralization in cultures treated with osteogenic inducers-dexamethasone (Dex) or bone morphogenetic protein. Increasing amounts of A2 in TiO2 matrix decreased cell viability but increased collagen deposition and mineralized matrix production by BMSC. Considering the physico-chemical and biological properties of the presented composites, the modification of TiO2 with SBG may prove useful strategy in several bone tissue related regeneration strategies.

  11. Iodination of vasopressin analogues with agonistic and antagonistic properties: effects on biological properties and affinity for vascular and renal vasopressin receptors.

    PubMed

    Jard, S; Lombard, C; Seyer, R; Aumelas, A; Manning, M; Sawyer, W H

    1987-09-01

    Twelve L- and D-tyrosine-containing vasopressin analogues were prepared in their mono- and diiodinated forms. These include six arginine vasopressin (AVP) vascular (V1) type antagonists/antidiuretic (V2) agonists, four V1/V2 antagonists, and two V1/V2 agonists, one of which is AVP itself. Ten peptides were iodinated on the tyrosyl residue in position 2; two were iodinated on a tyrosyl amide residue replacing the glycyl amide residue at position 9. All peptides were tested both for their biological activities in vivo (rat vasopressor and antidiuretic tests) and for their ability to bind to vasopressin receptors of the V1 (vascular) and V2 (renal) types from rat liver and rat kidney membranes, respectively. It is shown that monoiodination of the tyrosyl residue in the vasopressin analogues that were tested either preserves or reduces to a highly variable extent the in vivo and in vitro biological activities of these analogues. In most cases diiodonitation resulted in a marked decrease in biological activity. The effects of iodination on the affinity of vasopressin analogues for hepatic V1 receptors and renal V2 receptors were more related to the affinity of the noniodinated peptide for these receptors than to the biological properties (antagonist versus agonist) of the tested analogues, the nature (L versus D) of the iodinated tyrosyl residue, or the position (2 versus 9) at which this residue was introduced. The loss of affinity due to iodination was usually more pronounced for peptides exhibiting high affinity for vasopressin receptors. However, we show that among the monoiodinated peptides some (especially monoiodinated [2-D-Tyrosine]-AVP) retained enough affinity for vasopressin binding sites to suggest that their radioiodinated conterparts would be promising labeled ligands for use in studies in vasopressin receptors.

  12. The influence of halogen substituents on the biological properties of sulfur-containing flavonoids.

    PubMed

    Bahrin, Lucian Gabriel; Sarbu, Laura Gabriela; Hopf, Henning; Jones, Peter G; Babii, Cornelia; Stefan, Marius; Birsa, Mihail Lucian

    2016-07-15

    A series of halogen-substituted tricyclic flavonoids containing a 1,3-dithiol-2-ylium moiety has been synthesized from the corresponding 3-dithiocarbamic flavanones. The influence of halogen substituents on the antibacterial properties of the tricyclic flavonoids has been investigated against Staphylococcus aureus and Escherichia coli. On going from fluorine to iodine, these compounds exhibit good to excellent inhibitory properties against both Gram-positive and Gram-negative pathogens. These results suggest that size is the main factor for the change in potency rather than polarity/electronics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Biochemical Properties and Biological Function of a Monofunctional Microbial Biotin Protein Ligase

    PubMed Central

    Daniels, Kyle G.; Beckett, Dorothy

    2010-01-01

    Biotin protein ligases constitute a family of enzymes that catalyze biotin linkage to biotin-dependent carboxylases. In bacteria these enzymes are functionally divided into two classes; the monofunctional enzymes that only catalyze biotin addition and the bifunctional enzymes that also bind to DNA to regulate transcription initiation. Biochemical and biophysical studies of the bifunctional Escherichia coli ligase suggest that several properties of the enzyme have evolved to support its additional regulatory role. Included among these properties are the order of substrate binding and linkage between oligomeric state and ligand binding. PMID:20499837

  14. Properties of Resveratrol: In Vitro and In Vivo Studies about Metabolism, Bioavailability, and Biological Effects in Animal Models and Humans.

    PubMed

    Gambini, J; Inglés, M; Olaso, G; Lopez-Grueso, R; Bonet-Costa, V; Gimeno-Mallench, L; Mas-Bargues, C; Abdelaziz, K M; Gomez-Cabrera, M C; Vina, J; Borras, C

    2015-01-01

    Plants containing resveratrol have been used effectively in traditional medicine for over 2000 years. It can be found in some plants, fruits, and derivatives, such as red wine. Therefore, it can be administered by either consuming these natural products or intaking nutraceutical pills. Resveratrol exhibits a wide range of beneficial properties, and this may be due to its molecular structure, which endow resveratrol with the ability to bind to many biomolecules. Among these properties its activity as an anticancer agent, a platelet antiaggregation agent, and an antioxidant, as well as its antiaging, antifrailty, anti-inflammatory, antiallergenic, and so forth activities, is worth highlighting. These beneficial biological properties have been extensively studied in humans and animal models, both in vitro and in vivo. The issue of bioavailability of resveratrol is of paramount importance and is determined by its rapid elimination and the fact that its absorption is highly effective, but the first hepatic step leaves little free resveratrol. Clarifying aspects like stability and pharmacokinetics of resveratrol metabolites would be fundamental to understand and apply the therapeutic properties of resveratrol.

  15. Properties of Resveratrol: In Vitro and In Vivo Studies about Metabolism, Bioavailability, and Biological Effects in Animal Models and Humans

    PubMed Central

    Gambini, J.; Inglés, M.; Olaso, G.; Lopez-Grueso, R.; Bonet-Costa, V.; Gimeno-Mallench, L.; Mas-Bargues, C.; Abdelaziz, K. M.; Gomez-Cabrera, M. C.; Vina, J.; Borras, C.

    2015-01-01

    Plants containing resveratrol have been used effectively in traditional medicine for over 2000 years. It can be found in some plants, fruits, and derivatives, such as red wine. Therefore, it can be administered by either consuming these natural products or intaking nutraceutical pills. Resveratrol exhibits a wide range of beneficial properties, and this may be due to its molecular structure, which endow resveratrol with the ability to bind to many biomolecules. Among these properties its activity as an anticancer agent, a platelet antiaggregation agent, and an antioxidant, as well as its antiaging, antifrailty, anti-inflammatory, antiallergenic, and so forth activities, is worth highlighting. These beneficial biological properties have been extensively studied in humans and animal models, both in vitro and in vivo. The issue of bioavailability of resveratrol is of paramount importance and is determined by its rapid elimination and the fact that its absorption is highly effective, but the first hepatic step leaves little free resveratrol. Clarifying aspects like stability and pharmacokinetics of resveratrol metabolites would be fundamental to understand and apply the therapeutic properties of resveratrol. PMID:26221416

  16. Toxicant content, physical properties and biological activity of waterpipe tobacco smoke and its tobacco-free alternatives

    PubMed Central

    Shihadeh, Alan; Schubert, Jens; Klaiany, Joanne; El Sabban, Marwan; Luch, Andreas; Saliba, Najat A

    2015-01-01

    Objectives Waterpipe smoking using sweetened, flavoured tobacco products has become a widespread global phenomenon. In this paper, we review chemical, physical and biological properties of waterpipe smoke. Data sources Peer-reviewed publications indexed in major databases between 1991 and 2014. Search keywords included a combination of: waterpipe, narghile, hookah, shisha along with names of chemical compounds and classes of compounds, in addition to terms commonly used in cellular biology and aerosol sizing. Study selection The search was limited to articles published in English which reported novel data on waterpipe tobacco smoke (WTS) toxicant content, biological activity or particle size and which met various criteria for analytical rigour including: method specificity and selectivity, precision, accuracy and recovery, linearity, range, and stability. Data extraction Multiple researchers reviewed the reports and collectively agreed on which data were pertinent for inclusion. Data synthesis Waterpipe smoke contains significant concentrations of toxicants thought to cause dependence, heart disease, lung disease and cancer in cigarette smokers, and includes 27 known or suspected carcinogens. Waterpipe smoke is a respirable aerosol that induces cellular responses associated with pulmonary and arterial diseases. Except nicotine, smoke generated using tobacco-free preparations marketed for ‘health conscious’ users contains the same or greater doses of toxicants, with the same cellular effects as conventional products. Toxicant yield data from the analytical laboratory are consistent with studies of exposure biomarkers in waterpipe users. Conclusions A sufficient evidence base exists to support public health interventions that highlight the fact that WTS presents a serious inhalation hazard. PMID:25666550

  17. On the structural affinity of macromolecules with different biological properties: Molecular dynamics simulations of a series of TEM-1 mutants

    SciTech Connect

    Giampaolo, Alessia Di; Mazza, Fernando; Daidone, Isabella; Amicosante, Gianfranco; Perilli, Mariagrazia; Aschi, Massimiliano

    2013-07-12

    Highlights: •We have performed molecular dynamics simulations of TEM-1 mutants. •Mutations effects on the mechanical properties are considered. •Mutants do not significantly alter the average enzymes structure. •Mutants produce sharp alterations in enzyme conformational repertoire. •Mutants also produce changes in the active site volume. -- Abstract: Molecular Dynamics simulations have been carried out in order to provide a molecular rationalization of the biological and thermodynamic differences observed for a class of TEM β-lactamases. In particular we have considered the TEM-1(wt), the single point mutants TEM-40 and TEM-19 representative of IRT and ESBL classes respectively, and TEM-1 mutant M182T, TEM-32 and TEM-20 which differ from the first three for the additional of M182T mutation. Results indicate that most of the thermodynamic, and probably biological behaviour of these systems arise from subtle effects which, starting from the alterations of the local interactions, produce drastic modifications of the conformational space spanned by the enzymes. The present study suggests that systems showing essentially the same secondary and tertiary structure may differentiate their chemical–biological activity essentially (and probably exclusively) on the basis of the thermal fluctuations occurring in their physiological environment.

  18. Biological properties of dehydrated human amnion/chorion composite graft: implications for chronic wound healing.

    PubMed

    Koob, Thomas J; Rennert, Robert; Zabek, Nicole; Massee, Michelle; Lim, Jeremy J; Temenoff, Johnna S; Li, William W; Gurtner, Geoffrey

    2013-10-01

    Human amnion/chorion tissue derived from the placenta is rich in cytokines and growth factors known to promote wound healing; however, preservation of the biological activities of therapeutic allografts during processing remains a challenge. In this study, PURION® (MiMedx, Marietta, GA) processed dehydrated human amnion/chorion tissue allografts (dHACM, EpiFix®, MiMedx) were evaluated for the presence of growth factors, interleukins (ILs) and tissue inhibitors of metalloproteinases (TIMPs). Enzyme-linked immunosorbent assays (ELISA) were performed on samples of dHACM and showed quantifiable levels of the following growth factors: platelet-derived growth factor-AA (PDGF-AA), PDGF-BB, transforming growth factor α (TGFα), TGFβ1, basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), placental growth factor (PLGF) and granulocyte colony-stimulating factor (GCSF). The ELISA assays also confirmed the presence of IL-4, 6, 8 and 10, and TIMP 1, 2 and 4. Moreover, the relative elution of growth factors into saline from the allograft ranged from 4% to 62%, indicating that there are bound and unbound fractions of these compounds within the allograft. dHACM retained biological activities that cause human dermal fibroblast proliferation and migration of human mesenchymal stem cells (MSCs) in vitro. An in vivo mouse model showed that dHACM when tested in a skin flap model caused mesenchymal progenitor cell recruitment to the site of implantation. The results from both the in vitro and in vivo experiments clearly established that dHACM contains one or more soluble factors capable of stimulating MSC migration and recruitment. In summary, PURION® processed dHACM retains its biological activities related to wound healing, including the potential to positively affect four distinct and pivotal physiological processes intimately involved in wound healing: cell proliferation, inflammation, metalloproteinase activity and recruitment of progenitor cells. This suggests

  19. Impact of an intensive management on soil biochemical and biological properties in an agricultural soil of Southern Italy

    NASA Astrophysics Data System (ADS)

    Scotti, R.; D'Ascoli, R.; Rao, M. A.; Marzaioli, R.; Rutigliano, F. A.; Gianfreda, L.

    2009-04-01

    An intensive management of agricultural soils is widely carried out to increase vegetation productivity. Nevertheless, the large use of machineries, chemical fertilizers and pesticides can often cause, in time, a substantial decline in soil fertility by affecting soil physical and chemical properties and, in turn, growth and activity of soil microbial community. In fact, alteration in soil structure, nutrient losses and, in particular, changes in quality and quantity of soil organic matter are some of the principal soil degradation processes deriving from an intensive agricultural management that can affect, in different ways, soil biochemical and biological properties. The aim of this research was to assess the impact of intensive management on agricultural soils by measuring soil physical, chemical and biochemical/biological properties. The use of appropriate indicators as quantitative tools could allow to assess soil quality. Moreover, although soil physical and chemical properties have received great attention, soil biochemical/biological properties, such as enzyme activities and microbial biomass, functionally related properties involved in the nutrient cycles, can be considered as sensitive indicators of soil quality and health changes because, they show a faster turn over compared to soil organic matter. Our attention was focused on the Plane of Sele river (Campania region, Italy), an area characterized by an intensive agriculture and greenhouse cultures. Twenty-five farms were chosen, with the aid of regional soil map, in order to get soils with different physical and chemical properties. As common trait, the selected farms, all with greenhouse cultures, used no organic amendments but only mineral compounds to fertilize soils. Moreover, to better understand the impact of intensive agricultural practices on soil of each farm, control soils from orchards or uncultivated plots were chosen. In each farm soil samples were collected in three different plots

  20. [Biological effects of supplements on soil properties and the growth of Panax quinquefolium].

    PubMed

    Liu, H; Hu, B; Zhao, Y; Song, J; Zhang, G; Fu, J; Liu, W

    2000-04-01

    This paper suggests that the physical and chemical characteristics of soil in American ginseng field were greatly improved after utilization of supplement on soil. Compared with the contrast, the soil gravity ratio decreased from 0.812 g/cm3 to 0.715 g/cm3, while the soil porosity increased from 69.36% to 73.03%. These improvements are benefit for the growth of Panax quinquefolium. Biological observations show that the fresh weight of ginseng root enhanced 53.8%, and the content of total saponins in root enhanced 0.5%-1% (get to 8.28%).

  1. Modification of some biological properties of HeLa cells containing adeno-associated virus DNA integrated into chromosome 17.

    PubMed Central

    Walz, C; Schlehofer, J R

    1992-01-01

    Parvoviruses are known to interfere with cellular transformation and carcinogenesis. Since infecting adeno-associated virus (AAV) frequently integrates its DNA into the cellular genome, we analyzed whether this integration influences the transformed phenotype of the human tumor cell line HeLa. Analysis of three independent HeLa cell clones with integrated AAV DNA (HA-3x, HA-16, and HA-28) revealed the following phenotypic changes of these cells: (i) reduced growth rate, (ii) increased serum requirement, (iii) reduced capacity for colony formation in soft agar, (iv) reduced cloning efficiency on plastic, (v) elevated sensitivity to genotoxic agents (N-methyl-N'-nitro-N-nitrosoguanidine, 7,12-dimethylbenz[a]anthracene, human tumor necrosis factor alpha, UV irradiation [256 nm], and heat [42 degrees C]), and (vi) reduced sensitivity to the cytolytic effect of parvovirus H-1. Reduced growth rate and enhanced sensitivity to gamma irradiation were also observed in vivo when tumors from AAV DNA-containing HeLa cells were transplanted into nude mice. This alteration of the biological properties of HeLa cells was independent of the number of AAV genomes integrated, the physical structure of integrated AAV DNA, and the transcription of AAV genes. Integration of AAV DNA was found to occur preferentially on the long arm of chromosome 17 in the three HeLa cell clones analyzed. These findings demonstrate that genomic integration of AAV DNA can alter the biological properties of human tumor cells. Images PMID:1313913

  2. Lorentz contact resonance spectroscopy for nanoscale characterisation of structural and mechanical properties of biological, dental and pharmaceutical materials.

    PubMed

    Khanal, Dipesh; Dillon, Eoghan; Hau, Herman; Fu, Dong; Ramzan, Iqbal; Chrzanowski, Wojciech

    2015-12-01

    Scanning probe microscopy has been widely used to obtain topographical information and to quantify nanostructural properties of different materials. Qualitative and quantitative imaging is of particular interest to study material-material interactions and map surface properties on a nanoscale (i.e. stiffness and viscoelastic properties). These data are essential for the development of new biomedical materials. Currently, there are limited options to map viscoelastic properties of materials at nanoscale and at high resolutions. Lorentz contact resonance (LCR) is an emerging technique, which allows mapping viscoelasticity of samples with stiffness ranging from a few hundred Pa up to several GPa. Here we demonstrate the applicability of LCR to probe and map the viscoelasticity and stiffness of 'soft' (biological sample: cell treated with nanodiamond), 'medium hard' (pharmaceutical sample: pMDI canister) and 'hard' (human teeth enamel) specimens. The results allowed the identification of nanodiamond on the cells and the qualitative assessment of its distribution based on its nanomechanical properties. It also enabled mapping of the mechanical properties of the cell to demonstrate variability of these characteristics in a single cell. Qualitative imaging of an enamel sample demonstrated variations of stiffness across the specimen and precise identification of enamel prisms (higher stiffness) and enamel interrods (lower stiffness). Similarly, mapping of the pMDI canister wall showed that drug particles were adsorbed to the wall. These particles showed differences in stiffness at nanoscale, which suggested variations in surface composition-multiphasic material. LCR technique emerges as a valuable tool for probing viscoelasticity of samples of varying stiffness's.

  3. Rheological properties of a biological thermo-responsive hydrogel prepared from vegetable oil

    USDA-ARS?s Scientific Manuscript database

    Hydrogel is a colloidal gel in which water is the dispersion medium. The unique properties of hydrogels make this kind of materials have many utilization potentials, such as drug delivery, gene therapy, wound care products, breast implant materials, cosmetic products, and tissue engineering. Hydroge...

  4. Structure-Property-Function Relationship in Humic Substances to Explain the Biological Activity in Plants

    NASA Astrophysics Data System (ADS)

    García, Andrés Calderín; de Souza, Luiz Gilberto Ambrosio; Pereira, Marcos Gervasio; Castro, Rosane Nora; García-Mina, José María; Zonta, Everaldo; Lisboa, Francy Junior Gonçalves; Berbara, Ricardo Luis Louro

    2016-02-01

    Knowledge of the structure-property-function relationship of humic substances (HSs) is key for understanding their role in soil. Despite progress, studies on this topic are still under discussion. We analyzed 37 humic fractions with respect to their isotopic composition, structural characteristics, and properties responsible for stimulating plant root parameters. We showed that regardless of the source of origin of the carbon (C3 or C4), soil-extracted HSs and humic acids (HAs) are structurally similar to each other. The more labile and functionalized HS fraction is responsible for root emission, whereas the more recalcitrant and less functionalized HA fraction is related to root growth. Labile structures promote root stimulation at lower concentrations, while recalcitrant structures require higher concentrations to promote a similar stimulus. These findings show that lability and recalcitrance, which are derived properties of humic fractions, are related to the type and intensity of their bioactivity. In summary, the comparison of humic fractions allowed a better understanding of the relationship between the source of origin of plant carbon and the structure, properties, and type and intensity of the bioactivity of HSs in plants. In this study, scientific concepts are unified and the basis for the agronomic use of HSs is established.

  5. Structure-Property-Function Relationship in Humic Substances to Explain the Biological Activity in Plants

    PubMed Central

    García, Andrés Calderín; de Souza, Luiz Gilberto Ambrosio; Pereira, Marcos Gervasio; Castro, Rosane Nora; García-Mina, José María; Zonta, Everaldo; Lisboa, Francy Junior Gonçalves; Berbara, Ricardo Luis Louro

    2016-01-01

    Knowledge of the structure-property-function relationship of humic substances (HSs) is key for understanding their role in soil. Despite progress, studies on this topic are still under discussion. We analyzed 37 humic fractions with respect to their isotopic composition, structural characteristics, and properties responsible for stimulating plant root parameters. We showed that regardless of the source of origin of the carbon (C3 or C4), soil-extracted HSs and humic acids (HAs) are structurally similar to each other. The more labile and functionalized HS fraction is responsible for root emission, whereas the more recalcitrant and less functionalized HA fraction is related to root growth. Labile structures promote root stimulation at lower concentrations, while recalcitrant structures require higher concentrations to promote a similar stimulus. These findings show that lability and recalcitrance, which are derived properties of humic fractions, are related to the type and intensity of their bioactivity. In summary, the comparison of humic fractions allowed a better understanding of the relationship between the source of origin of plant carbon and the structure, properties, and type and intensity of the bioactivity of HSs in plants. In this study, scientific concepts are unified and the basis for the agronomic use of HSs is established. PMID:26862010

  6. A Comprehensive Review of Punica granatum (Pomegranate) Properties in Toxicological, Pharmacological, Cellular and Molecular Biology Researches

    PubMed Central

    Rahimi, Hamid Reza; Arastoo, Mohammad; Ostad, Seyed Nasser

    2012-01-01

    Punica granatum (Pg), commonly known as pomegranate (Pg), is a member of the monogeneric family, Punicaceae, and is mainly found in Iran which is considered to be its primary centre of origin. Pg and its chemical components possess various pharmacological and toxicological properties including antioxidant, anti-inflammatory (by inhibiting pro-inflammatory cytokines), anti-cancer and anti-angiogenesis activities. They also show inhibitory effects on invasion/motility, cell cycle, apoptosis, and vital enzymes such as cyclooxygenase (COX), lipooxygenase (LOX), cytochrome P450 (CYP450), phospholipase A2 (PLA2), ornithine decarboxylase (ODC), carbonic anhydrase (CA), 17beta-hydroxysteroid dehydrogenase (17β-HSDs) and serine protease (SP). Furthermore, they can stimulate cell differentiation and possess anti-mutagenic effects. Pg can also interfere with several signaling pathways including PI3K/AKT, mTOR, PI3K, Bcl-X, Bax, Bad, MAPK, ERK1/2, P38, JNK, and caspase. However, the exact mechanisms for its pharmacological and toxicological properties remain to be unclear and need further evaluation. These properties strongly suggest a wide range use of Pg for clinical applications. This review will discuss the areas for which Pg has shown therapeutic properties in different mechanisms. PMID:24250463

  7. Cellulose Nanocrystal Entrapment of Benzalkonium Chloride in Southern Pine: Biological, Chemical, and Physical Properties

    Treesearch

    Carol A. Clausen; Vina W. Yang; Rachel A. Arango; Laura E. Hasburgh; Patricia K. Lebow; Richard S. Reiner

    2015-01-01

    Protecting wood products from biodeterioration has been a dynamic area of research in the past decade with an emphasis on the development of non-arsenical wood preservatives. Naturally occurring cellulose nanomaterials that are reported to have unique chemical properties, high strength, and stiffness were evaluated for the potential to improve durability of wood either...

  8. Preparation, characterization, and biological properties of organic-inorganic nanocomposite coatings on titanium substrates prepared by sol-gel.

    PubMed

    Catauro, Michelina; Bollino, Flavia; Papale, Ferdinando

    2014-02-01

    When surface-reactive (bioactive) coatings are applied to medical implants by means of the sol-gel dip-coating technique, the biological proprieties of the surface of the implant can be locally modified to match the properties of the surrounding tissues to provide a firm fixation of the implant. The aim of this study has been to synthesize, via sol-gel, organoinorganic nanoporous materials and to dip-coat a substrate to use in dental applications. Different systems have been prepared consisting of an inorganic zirconium-based matrix, in which a biodegradable polymer, the poly-ε-caprolactone was incorporated in different percentages. The materials synthesized by the sol-gel process, before gelation, when they were still in sol phase, have been used to coat a titanium grade 4 (Ti-4) substrate to change its surface biological properties. Thin films have been obtained by means of the dip-coating technique. A microstructural analysis of the obtained coatings was performed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. The biological proprieties have been investigated by means of tests in vitro. The bone-bonding capability of the nanocomposite films has been evaluated by examining the appearance of apatite on their surface when plunged in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma. The examination of apatite formation on the nanocomposites, after immersion in SBF, has been carried out by SEM equipped with energy-dispersive X-ray spectroscopy. To evaluate cells-materials interaction, human osteosarcoma cell line (Saos-2) has been seeded on specimens and cell vitality evaluated by WST-8 assay. © 2013 Wiley Periodicals, Inc.

  9. Evaluation of biological, physical and chemical properties of mineral trioxide aggregate mixed with 4-META/MMA-TBB.

    PubMed

    Kaul, Rudra; Farooq, Riyaz; Kaul, Vibhuti; Malik, Altaf H; Purra, Aamir Rashid; Ahmad, Lateef

    2013-01-01

    To evaluate the change in physical, chemical and biological properties when mineral trioxide aggregate (MTA) is mixed with a resin 4-methacryloxyethyl trimellitate anhydride (4-META)/methyl methacrylate-tri-n-butyl-borane (MMA)-TBB. For biological evaluation MTA was inoculated in Wistar rat's subcutaneous tissue and peripheral tissue response was checked after 72 h, 7 days, 15 days and 30 days. Setting time was evaluated using Gillmore needle. The Ca++ release at the end of 24 h was checked using ethylenediaminetetraacetic acid titration method. For all the trials MTA mixed with water was kept as a control and the ratio of MTA with resin was 1:1 by weight. The biological reaction was verified by two observers and their readings were matched using kappa test and there was an excellent relevance. There was no significant difference in the tissue reaction at the end of 30 days where both the groups seemed to show healing. Setting time of MTA with 4-META/MMA-TBB was coming to a mean of 26 min (approx.), which is almost 6 times lesser than that of MTA with water. After applying t test, the difference in Ca++ release was found significant (P = 0.00), with mean of 0.044 and 0.031 mol/L of MTA with water and MTA with 4-META/MMA-TBB respectively. Under the parameters of this study, this new experimental cement has better handling, physical and chemical properties. Even its subcutaneous tissue reaction is comparable to MTA mixed with water.

  10. Biological and polymeric self-assembled hybrid systems: structure and properties of thylakoid/polyelectrolyte complexes.

    PubMed

    Dementiev, A A; Baikov, A A; Ptushenko, V V; Khomutov, G B; Tikhonov, A N

    2005-06-15

    A novel hybrid system composed of biological components and synthetic polymer, thylakoid/polycation complex, has been formed and studied. Effects of complex formation on the structure, electrostatics and functioning of thylakoid membranes have been examined. Thylakoids from bean leaves were used to form complexes with polycation polyallylamine hydrochloride (PAAH) in two systems: (i) thylakoid/polycation complexes formed in an aqueous bulk phase, and (ii) immobilized thylakoid/polycation planar complexes. Immobilized on a solid substrate surface, thylakoid/polycation complexes were prepared using layer-by-layer stepwise alternate adsorption technique, i.e., via the sequential alternate adsorption of thylakoids and polycation molecules. The morphology of built up structures was investigated by scanning electron microscopy. Light-induced electron transport in chloroplasts was studied by the electron paramagnetic resonance (EPR) method. Spin probe technique was employed to study the structural and electrostatic characteristics of thylakoid membranes. We have found that efficiency of light-induced electron transport in thylakoid membranes and membrane structure were not changed noticeably by PAAH binding to thylakoids in a wide range of PAAH concentrations. The data obtained indicate the physiologically-soft character of polycation interactions with thylakoid membranes and demonstrate effectiveness of interfacial self-assembly approach to fabrication of complex planar functional nanostructures from biological components and synthetic polymers.

  11. A biologically effective fullerene (C60) derivative with superoxide dismutase mimetic properties.

    PubMed

    Ali, Sameh S; Hardt, Joshua I; Quick, Kevin L; Kim-Han, Jeong Sook; Erlanger, Bernard F; Huang, Ting-Ting; Epstein, Charles J; Dugan, Laura L

    2004-10-15

    Superoxide, a potentially toxic by-product of cellular metabolism, may contribute to tissue injury in many types of human disease. Here we show that a tris-malonic acid derivative of the fullerene C60 molecule (C3) is capable of removing the biologically important superoxide radical with a rate constant (k(C3)) of 2 x 10(6) mol(-1) s(-1), approximately 100-fold slower than the superoxide dismutases (SOD), a family of enzymes responsible for endogenous dismutation of superoxide. This rate constant is within the range of values reported for several manganese-containing SOD mimetic compounds. The reaction between C3 and superoxide was not via stoichiometric "scavenging," as expected, but through catalytic dismutation of superoxide, indicated by lack of structural modifications to C3, regeneration of oxygen, production of hydrogen peroxide, and absence of EPR-active (paramagnetic) products, all consistent with a catalytic mechanism. A model is proposed in which electron-deficient regions on the C60 sphere work in concert with malonyl groups attached to C3 to electrostatically guide and stabilize superoxide, promoting dismutation. We also found that C3 treatment of Sod2(-/-) mice, which lack expression of mitochondrial manganese superoxide dismutase (MnSOD), increased their life span by 300%. These data, coupled with evidence that C3 localizes to mitochondria, suggest that C3 functionally replaces MnSOD, acting as a biologically effective SOD mimetic.

  12. Mount St. Helens Ash from the 18 May 1980 Eruption: Chemical, Physical, Mineralogical, and Biological Properties

    NASA Astrophysics Data System (ADS)

    Fruchter, Jonathan S.; Robertson, David E.; Evans, John C.; Olsen, Khris B.; Lepel, Elwood A.; Laul, Jagdish C.; Abel, Keith H.; Sanders, Ronald W.; Jackson, Peter O.; Wogman, Ned S.; Perkins, Richard W.; van Tuyl, Harold H.; Beauchamp, Raymond H.; Shade, John W.; Leland Daniel, J.; Erikson, Robert L.; Sehmel, George A.; Lee, Richard N.; Robinson, Alfred V.; Moss, Owen R.; Briant, James K.; Cannon, William C.

    1980-09-01

    Samples of ash from the 18 May 1980 eruption of Mount St. Helens were collected from several locations in eastern Washington and Montana. The ash was subjected to a variety of analyses to determine its chemical, physical, mineralogical, and biological characteristics. Chemically, the ash samples were of dacitic composition. Particle size data showed bimodal distributions and differed considerably with location. However, all samples contained comparable amounts of particles less than 3.5 micrometers in diameter (respirable fraction). Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystalline samples were dominated by plagioclase feldspar (andesine) and orthopyroxene (hypersthene), with smaller amounts of titanomagnetite and hornblende. All but one of the samples contained from less than 1 percent to 3 percent free crystalline silica (quartz, trydimite, or cristobalite) in both the bulk samples and 1 to 2 percent in the fractions smaller than 3.5 micrometers. The long-lived natural radionuclide content of the ash was comparable to that of crustal material; however, relatively large concentrations of short-lived radon daughters were present and polonium-210 content was inversely correlated with particle size. In vitro biological tests showed the ash to be nontoxic to alveolar macrophages, which are an important part of the lungs' natural clearance mechanism. On the basis of a substantial body of data that has shown a correlation between macrophage cytotoxicity and fibrogenicity of minerals, the ash is not predicted to be highly fibrogenic.

  13. Mount St. Helens ash from the 18 May 1980 eruption: chemical, physical, mineralogical, and biological properties

    SciTech Connect

    Fruchter, J.S.; Robertson, D.E.; Evans, J.C.

    1980-09-05

    Samples of ash from the 18 May 1980 eruption of Mount St. Helens were collected from several locations in eastern Washington and Montana. The ash was subjected to a variety of analyses to determine its chemical, physical, mineralogical, and biological characteristics. Chemically, the ash samples were of dacitic composition. Particle size data showed bimodal distributions and differed considerably with location. However, all samples contained comparable amounts of particles less than 3.5 micrometers in diameter (respirable fraction). Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystalline samples were dominated by plagioclase feldspar (andesine) and orthopyroxene (hypersthene), with smaller amounts of titanomagnetite and hornblende. All but one of the samples contained from less than 1% to 3% free crystalline silica (quartz, trydimite, or cristobalite) in both the bulk samples and 1 to 2% in the fractions smaller than 3.5 micrometers. The long-lived natural radionuclide content of the ash was comparable to that of crustal material; however, relatively large concentrations of short-lived radon daughters were present and polonium-210 content was inversely correlated with particle size. In vitro biological tests showed the ash to be nontoxic to alveolar macrophages, which are an important pat of the lungs' natural clearance mechanism. On the basis of a substantial body of data that has shown a correlation between macrophage cytotoxicity and fibrogenicity of minerals, the ash is not predicted to be highly fibrogenic.

  14. Mount st. Helens ash from the 18 may 1980 eruption: chemical, physical, mineralogical, and biological properties.

    PubMed

    Fruchter, J S; Robertson, D E; Evans, J C; Olsen, K B; Lepel, E A; Laul, J C; Abel, K H; Sanders, R W; Jackson, P O; Wogman, N S; Perkins, R W; VAN Tuyl, H H; Beauchamp, R H; Shade, J W; Daniel, J L; Erikson, R L; Sehmel, G A; Lee, R N; Robinson, A V; Moss, O R; Briant, J K; Cannon, W C

    1980-09-05

    Samples of ash from the 18 May 1980 eruption of Mount St. Helens were collected from several locations in eastern Washington and Montana. The ash was subjected to a variety of analyses to determine its chemical, physical, mineralogical, and biological characteristics. Chemically, the ash samples were of dacitic composition. Particle size data showed bimodal distributions and differed considerably with location. However, all samples contained comparable amounts of particles less than 3.5 micrometers in diameter (respirable fraction). Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystalline samples were dominated by plagioclase feldspar (andesine) and orthopyroxene (hypersthene), with smaller amounts of titanomagnetite and hornblende. All but one of the samples contained from less than 1 percent to 3 percent free crystalline silica (quartz, trydimite, or cristobalite) in both the bulk samples and 1 to 2 percent in the fractions smaller than 3.5 micrometers. The long-lived natural radionuclide content of the ash was comparable to that of crustal material; however, relatively large concentrations of short-lived radon daughters were present and polonium-210 content was inversely correlated with particle size. In vitro biological tests showed the ash to be nontoxic to alveolar macrophages, which are an important part of the lungs' natural clearance mechanism. On the basis of a substantial body of data that has shown a correlation between macrophage cytotoxicity and fibrogenicity of minerals, the ash is not predicted to be highly fibrogenic.

  15. Biological and nutritional properties of blackcurrant berries (Ribes nigrum L.) under conditions of shading nets.

    PubMed

    Djordjevic, Boban; Šavikin, Katarina; Djurovic, Dejan; Veberic, Robert; Mikulič Petkovšek, Maja; Zdunić, Gordana; Vulic, Todor

    2015-09-01

    Changes of environmental factors, created under the influence of various shading nets, could significantly affect the biological characteristics of plants grown in such conditions as well as biosynthesis of primary metabolites and ascorbic acid. Five blackcurrant cultivars - 'Ben Sarek', 'Ben Nevis', 'Ben Lomond', 'Ometa' and 'Čačanska Crna' - were cultivated in the shade of two green polyethylene nets and exposed to direct sunlight during two experimental seasons. In the control treatment, all cultivars contained the highest amounts of soluble solid content and number of flower buds per shoot in both years of cultivation. The bushes exposed to direct sunlight had the highest sunburn damage to the berries and leaves, and loss of yield. The greatest yield loss caused by berry damage in the present study during the experimental period was in cultivar 'Ben Sarek': 9.0% in 2010 and 15.4% in 2011. Growing in the shade of light-green net contributed the highest content of ascorbic acid. Control bushes and those shaded by light-green net had significantly higher radical scavenging activity, with values between 1.15 and 1.22 mg mL(-1). Plants shaded by nets in both years of cultivation had lower damage to leaves and berries and percentage of loss of yield, and usage of the net would be economically advantageous to growers. Fruit of blackcurrant cultivars grown in shading conditions still represent a good source of valuable nutritive and biologically active compounds. © 2014 Society of Chemical Industry.

  16. Nanoparticles to increase adhesive properties of biologically secreted materials for surface affixing.

    PubMed

    Zhang, Mingjun; Liu, Maozi; Bewick, Sharon; Suo, Zhiyong

    2009-06-01

    Surface adhesion in nature has been the focus of intense study over the past few years. Nevertheless, research in this field has primarily concentrated on understanding the chemical aspects of adhesion. While scientists have been able to determine some of the molecular structures present in the adhesives secreted by surface climbing or surface affixing biological systems such as mussels and barnacles, the fundamental adhesion mechanisms used by these systems are still unknown. This research paper focuses on the nano-scale morphological similarities of adhesive materials secreted from marine mussels, barnacles and ivy. We discovered that marine mussels secrete large amounts of adhesive materials in the form of nanoparticles for surface adhesion. This is in keeping with our previous work, which indicated a similar phenomenon for ivy. Both studies concur with earlier research on marine barnacles, polychaetes and sea stars. Taken together, these results indicate that nanoparticles are used by natural, biological systems to increase surface adhesion. These nanoparticle surface adhesion mechanisms have important implications in terms of engineering surface adhesive materials and devices.

  17. Borreria and Spermacoce species (Rubiaceae): A review of their ethnomedicinal properties, chemical constituents, and biological activities.

    PubMed

    Conserva, Lucia Maria; Ferreira, Jesu Costa

    2012-01-01

    Borreira and Spermacoce are genera of Rubiaceae widespread in tropical and subtropical America, Africa, Asia, and Europe. Based on its fruits morphology they are considered by many authors to be distinct genera and most others, however, prefer to combine the two taxa under the generic name Spermacoce. Whereas the discussion is still unclear, in this work they were considered as synonyms. Some species of these genera play an important role in traditional medicine in Africa, Asia, Europe, and South America. Some of these uses include the treatment of malaria, diarrheal and other digestive problems, skin diseases, fever, hemorrhage, urinary and respiratory infections, headache, inflammation of eye, and gums. To date, more than 60 compounds have been reported from Borreria and Spermacoce species including alkaloids, iridoids, flavonoids, terpenoids, and other compounds. Studies have confirmed that extracts from Borreria and Spermacoce species as well as their isolated compounds possess diverse biological activities, including anti-inflammatory, antitumor, antimicrobial, larvicidal, antioxidant, gastrointestinal, anti-ulcer, and hepatoprotective, with alkaloids and iridoids as the major active principles. This paper briefly reviews the ethnomedicinal uses, phytochemistry, and biological activities of some isolated compounds and extracts of both genera.

  18. A discrete spectral analysis for determining quasi-linear viscoelastic properties of biological materials

    PubMed Central

    Babaei, Behzad; Abramowitch, Steven D.; Elson, Elliot L.; Thomopoulos, Stavros; Genin, Guy M.

    2015-01-01

    The viscoelastic behaviour of a biological material is central to its functioning and is an indicator of its health. The Fung quasi-linear viscoelastic (QLV) model, a standard tool for characterizing biological materials, provides excellent fits to most stress–relaxation data by imposing a simple form upon a material's temporal relaxation spectrum. However, model identification is challenging because the Fung QLV model's ‘box’-shaped relaxation spectrum, predominant in biomechanics applications, can provide an excellent fit even when it is not a reasonable representation of a material's relaxation spectrum. Here, we present a robust and simple discrete approach for identifying a material's temporal relaxation spectrum from stress–relaxation data in an unbiased way. Our ‘discrete QLV’ (DQLV) approach identifies ranges of time constants over which the Fung QLV model's typical box spectrum provides an accurate representation of a particular material's temporal relaxation spectrum, and is effective at providing a fit to this model. The DQLV spectrum also reveals when other forms or discrete time constants are more suitable than a box spectrum. After validating the approach against idealized and noisy data, we applied the methods to analyse medial collateral ligament stress–relaxation data and identify the strengths and weaknesses of an optimal Fung QLV fit. PMID:26609064

  19. A discrete spectral analysis for determining quasi-linear viscoelastic properties of biological materials.

    PubMed

    Babaei, Behzad; Abramowitch, Steven D; Elson, Elliot L; Thomopoulos, Stavros; Genin, Guy M

    2015-12-06

    The viscoelastic behaviour of a biological material is central to its functioning and is an indicator of its health. The Fung quasi-linear viscoelastic (QLV) model, a standard tool for characterizing biological materials, provides excellent fits to most stress-relaxation data by imposing a simple form upon a material's temporal relaxation spectrum. However, model identification is challenging because the Fung QLV model's 'box'-shaped relaxation spectrum, predominant in biomechanics applications, can provide an excellent fit even when it is not a reasonable representation of a material's relaxation spectrum. Here, we present a robust and simple discrete approach for identifying a material's temporal relaxation spectrum from stress-relaxation data in an unbiased way. Our 'discrete QLV' (DQLV) approach identifies ranges of time constants over which the Fung QLV model's typical box spectrum provides an accurate representation of a particular material's temporal relaxation spectrum, and is effective at providing a fit to this model. The DQLV spectrum also reveals when other forms or discrete time constants are more suitable than a box spectrum. After validating the approach against idealized and noisy data, we applied the methods to analyse medial collateral ligament stress-relaxation data and identify the strengths and weaknesses of an optimal Fung QLV fit. © 2015 The Author(s).

  20. Borreria and Spermacoce species (Rubiaceae): A review of their ethnomedicinal properties, chemical constituents, and biological activities

    PubMed Central

    Conserva, Lucia Maria; Ferreira, Jesu Costa

    2012-01-01

    Borreira and Spermacoce are genera of Rubiaceae widespread in tropical and subtropical America, Africa, Asia, and Europe. Based on its fruits morphology they are considered by many authors to be distinct genera and most others, however, prefer to combine the two taxa under the generic name Spermacoce. Whereas the discussion is still unclear, in this work they were considered as synonyms. Some species of these genera play an important role in traditional medicine in Africa, Asia, Europe, and South America. Some of these uses include the treatment of malaria, diarrheal and other digestive problems, skin diseases, fever, hemorrhage, urinary and respiratory infections, headache, inflammation of eye, and gums. To date, more than 60 compounds have been reported from Borreria and Spermacoce species including alkaloids, iridoids, flavonoids, terpenoids, and other compounds. Studies have confirmed that extracts from Borreria and Spermacoce species as well as their isolated compounds possess diverse biological activities, including anti-inflammatory, antitumor, antimicrobial, larvicidal, antioxidant, gastrointestinal, anti-ulcer, and hepatoprotective, with alkaloids and iridoids as the major active principles. This paper briefly reviews the ethnomedicinal uses, phytochemistry, and biological activities of some isolated compounds and extracts of both genera. PMID:22654404

  1. Short cationic lipopeptides as effective antibacterial agents: Design, physicochemical properties and biological evaluation.

    PubMed

    Azmi, Fazren; Elliott, Alysha G; Marasini, Nirmal; Ramu, Soumya; Ziora, Zyta; Kavanagh, Angela M; Blaskovich, Mark A T; Cooper, Matthew A; Skwarczynski, Mariusz; Toth, Istvan

    2016-05-15

    The spread of drug-resistant bacteria has imparted a sense of urgency in the search for new antibiotics. In an effort to develop a new generation of antibacterial agents, we have designed de novo charged lipopeptides inspired by natural antimicrobial peptides. These short lipopeptides are composed of cationic lysine and hydrophobic lipoamino acids that replicate the amphiphilic properties of natural antimicrobial peptides. The resultant lipopeptides were found to self-assemble into nanoparticles. Some were effective against a variety of Gram-positive bacteria, including strains resistant to methicillin, daptomycin and/or vancomycin. The lipopeptides were not toxic to human kidney and liver cell lines and were highly resistant to tryptic degradation. Transmission electron microscopy analysis of bacteria cells treated with lipopeptide showed membrane-damage and lysis with extrusion of cytosolic contents. With such properties in mind, these lipopeptides have the potential to be developed as new antibacterial agents against drug-resistant Gram-positive bacteria.

  2. Tuning optical properties of water-soluble CdTe quantum dots for biological applications

    NASA Astrophysics Data System (ADS)

    Schulze, Anne S.; Tavernaro, Isabella; Machka, Friederike; Dakischew, Olga; Lips, Katrin S.; Wickleder, Mathias S.

    2017-02-01

    In this study, two different synthetic methods in aqueous solution are presented to tune the optical properties of CdTe and CdSe semiconductor nanoparticles. Additionally, the influence of different temperatures, pressures, precursor ratios, surface ligands, bases, and core components in the synthesis was investigated with regard to the particle sizes and optical properties. As a result, a red shift of the emission and absorption maxima with increasing reaction temperature (100 to 220°C), pressure (1 to 25 bar), and different ratios of core components of alloyed semiconductor nanoparticles could be observed without a change of the particle size. An increase in particle size from 2.5 to 5 nm was only achieved by variation of the mercaptocarboxylic acid ligands in combination with the reaction time and used base. To get a first hint on the cytotoxic effects and cell uptake of the synthesized quantum dots, in vitro tests mesenchymal stem cells (MSCs) were carried out.

  3. Biological properties of propolis extracts: Something new from an ancient product.

    PubMed

    Zabaiou, Nada; Fouache, Allan; Trousson, Amalia; Baron, Silvère; Zellagui, Amar; Lahouel, Mesbah; Lobaccaro, Jean-Marc A

    2017-10-01

    Natural products are an interesting source of new therapeutics, especially for cancer therapy as 70% of them have botany origin. Propolis, a resinous mixture that honey bees collect and transform from tree buds, sap flows, or other botanical sources, has been used by ethnobotany and traditional practitioners as early in Egypt as 3000 BCE. Enriched in flavonoids, phenol acids and terpene derivatives, propolis has been widely used for its antibacterial, antifungal and anti-inflammatory properties. Even though it is a challenge to standardize propolis composition, chemical analyses have pointed out interesting molecules that also present anti-oxidant and anti-proliferative properties that are of interest in the field of anti-cancer therapy. This review describes the various geographical origins and compositions of propolis, and analyzes how the main compounds of propolis could modulate cell signaling. A focus is made on the putative use of propolis in prostate cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Overview of β-Glucans from Laminaria spp.: Immunomodulation Properties and Applications on Biologic Models

    PubMed Central

    Bonfim-Mendonça, Patrícia de Souza; Capoci, Isis Regina Grenier; Tobaldini-Valerio, Flávia Kelly; Negri, Melyssa; Svidzinski, Terezinha Inez Estivalet

    2017-01-01

    Glucans are a group of glucose polymers that are found in bacteria, algae, fungi, and plants. While their properties are well known, their biochemical and solubility characteristics vary considerably, and glucans obtained from different sources can have different applications. Research has described the bioactivity of β-glucans extracted from the algae of the Laminaria genus, including in vivo and in vitro studies assessing pro- and anti-inflammatory cytokines, vaccine production, inhibition of cell proliferation, and anti- and pro-oxidant activity. Thus, the objective of this article was to review the potential application of β-glucans from Laminaria spp. in terms of their immunomodulatory properties, microorganism host interaction, anti-cancer activity and vaccine development. PMID:28878139

  5. Overview of β-Glucans from Laminaria spp.: Immunomodulation Properties and Applications on Biologic Models.

    PubMed

    Bonfim-Mendonça, Patrícia de Souza; Capoci, Isis Regina Grenier; Tobaldini-Valerio, Flávia Kelly; Negri, Melyssa; Svidzinski, Terezinha Inez Estivalet

    2017-09-06

    Glucans are a group of glucose polymers that are found in bacteria, algae, fungi, and plants. While their properties are well known, their biochemical and solubility characteristics vary considerably, and glucans obtained from different sources can have different applications. Research has described the bioactivity of β-glucans extracted from the algae of the Laminaria genus, including in vivo and in vitro studies assessing pro- and anti-inflammatory cytokines, vaccine production, inhibition of cell proliferation, and anti- and pro-oxidant activity. Thus, the objective of this article was to review the potential application of β-glucans from Laminaria spp. in terms of their immunomodulatory properties, microorganism host interaction, anti-cancer activity and vaccine development.

  6. Correlative study of properties of water in biological systems using ultrasound and magnetic resonance.

    PubMed

    Sehgal, C M; Greenleaf, J F

    1986-12-01

    Ultrasonic and nuclear magnetic resonance properties of media rich in water are investigated. The chemical shift of the water proton in pure water, aqueous solutions of tertiary butanol, and sodium chloride is shown to be linearly correlated to the reciprocal of sound speed in these media. A new method of determining the self-diffusion coefficient of water by using acoustic nonlinearity and sound speed is proposed. The method is tested on a variety of media that include pure water, aqueous solutions of glycerol, serum albumin, egg constituents, plant tissues, frog muscle and liver, and excised human tissues. In all the cases the results are found to compare closely to diffusion coefficients measured by magnetic resonance. The results presented here indicate that the acoustic and magnetic resonance modalities, though inherently different in their origin, can provide closely related information on the properties of water.

  7. Physical properties of iron-sulfur Fe6S6 superclusters important for biological systems.

    PubMed

    Ozga, Julita; Matusiewicz, Marek; Kasperczyk, Jacek; Kozlowski, Gregory; Kityk, Ivan

    2011-01-01

    The theoretical analysis of the thermal and magnetic properties of iron-sulfur superclusters has been studied by taking into account Heisenberg interactions and resonance delocalizations (double exchange interactions). The numerical calculations are based on the determination of the lowest energy states for different values of spins (from S = 0.5 to S = 12.5) and Heisenberg exchange integrals. It is shown that the spin magnetic susceptibility of the iron-sulfur superclusters decreases with increasing temperature and increases with increasing the double exchange parameter. In contrast to the susceptibility, the heat capacity decreases with the increasing values of the double exchange parameter. It was theoretically found that spin of ground state for the iron-sulfur supercluster is equal to 0.5. Based on our results, we can state that the Heisenberg model of spin interactions describes the thermodynamic properties of the iron-sulfur superclusters which are the important constituents of proteins and enzymes.

  8. Doped tricalcium phosphate bone tissue engineering scaffolds using sucrose as template and microwave sintering: enhancement of mechanical and biological properties.

    PubMed

    Ke, Dongxu; Bose, Susmita

    2017-09-01

    β-tricalcium phosphate (β-TCP) is a widely used biocompatible ceramic in orthopedic and dental applications. However, its osteoinductivity and mechanical properties still require improvements. In this study, porous β-TCP and MgO/ZnO-TCP scaffolds were prepared by the thermal decomposition of sucrose. Crack-free cylindrical scaffolds could only be prepared with the addition of MgO and ZnO due to their stabilization effects. Porous MgO/ZnO-TCP scaffolds with a density of 61.39±0.66%, an estimated pore size of 200μm and a compressive strength of 24.96±3.07MPa were prepared by using 25wt% sucrose after conventional sintering at 1250°C. Microwave sintering further increased the compressive strength to 37.94±6.70MPa, but it decreased the open interconnected porosity to 8.74±1.38%. In addition, the incorporation of polycaprolactone (PCL) increased 22.36±3.22% of toughness while maintaining its compressive strength at 25.45±2.21MPa. Human osteoblast cell line was seeded on scaffolds to evaluate the effects of MgO/ZnO and PCL on the biological property of β-TCP in vitro. Both MgO/ZnO and PCL improved osteoinductivity of β-TCP. PCL also decreased osteoblastic apoptosis due to its particular surface chemistry. This novel porous MgO/ZnO-TCP scaffold with PCL shows improved mechanical and biological properties, which has great potential in bone tissue engineering applications. Copyright © 2017. Published by Elsevier B.V.

  9. Effects of seasonal olive mill wastewater applications on hydrological and biological soil properties in an olive orchard in Israel

    NASA Astrophysics Data System (ADS)

    Steinmetz, Zacharias; Kurtz, Markus; Peikert, Benjamin; Zipori, Isaac; Dag, Arnon; Schaumann, Gabriele E.

    2014-05-01

    During olive oil production in Mediterranean countries, large amounts of olive mill wastewater (OMW) are generated within a short period of time. OMW has a high nutrient content and could serve as fertilizer when applied on land. However, its fatty and phenolic constituents have adverse effects on hydrological and biological soil properties. It is still unknown how seasonal fluctuations in temperature and precipitation influence the fate and effect of OMW components on soil in a long-term perspective. An appropriate application season could mitigate negative consequences of OMW while preserving its beneficial effects. In order to investigate this, 14 L OMW m-2 were applied to different plots of an olive orchard in Gilat, Israel, in winter, spring, and summer, respectively. Hydrological soil properties (water drop penetration time, hydraulic conductivity, dynamic contact angle), physicochemical parameters (pH, EC, soluble ions, phenolic compounds, organic matter), and biological degradation (bait-lamina test) were measured to assess the soil state after OMW application. After one rainy season following OMW application, the soil quality of summer treatments significantly decreased compared to the control. This was particularly apparent in a ten-fold higher soil water repellency, a three-times lower biodegradation performance, and a four-fold higher content of phenolic compounds. 1.5 years after the last OMW application, the soil properties of winter treatments were comparable to the control, which suggests a certain recovery potential of the soil. Spring treatments resulted in an intermediate response compared to summer and winter treatments, but without any precipitation following OMW application. Strongest OMW effects were found in the top soil layers. Further research is needed to quantify the effect of spring treatments as well as to gain further insight into leaching effects, the composition of organic OMW constituents, and the kinetics of their degradation in

  10. Non-contact, Ultrasound-based Indentation Method for Measuring Elastic Properties of Biological Tissues Using Harmonic Motion Imaging (HMI)

    PubMed Central

    Vappou, Jonathan; Hou, Gary Y.; Marquet, Fabrice; Shahmirzadi, Danial; Grondin, Julien; Konofagou, Elisa E.

    2015-01-01

    Noninvasive measurement of mechanical properties of biological tissues in vivo could play a significant role in improving the current understanding of tissue biomechanics. In this study, we propose a method for measuring elastic properties non-invasively by using internal indentation as generated by Harmonic Motion Imaging (HMI). In HMI, an oscillating acoustic radiation force is produced by a focused ultrasound transducer at the focal region, and the resulting displacements are estimated by tracking RF signals acquired by an imaging transducer. In this study, the focal spot region was modeled as a rigid cylindrical piston that exerts an oscillatory, uniform internal force to the underlying tissue. The HMI elastic modulus EHMI was defined as the ratio of the applied force to the axial strain measured by 1D ultrasound imaging. The accuracy and the precision of the EHMI estimate were assessed both numerically and experimentally in polyacrylamide tissue-mimicking phantoms. Initial feasibility of this method in soft tissues was also shown in canine liver specimens in vitro. Very good correlation and agreement was found between the actual Young’s modulus and the HMI modulus in the numerical study (r2>0.99, relative error <10%) and on polyacrylamide gels (r2=0.95, relative error <24%). The average HMI modulus on five liver samples was found to EHMI=2.62±0.41 kPa, compared to EMechTesting=4.2±2.58 kPa measured by rheometry. This study has demonstrated for the first time the initial feasibility of a non-invasive, model-independent method to estimate local elastic properties of biological tissues at a submillimeter scale using an internal indentation-like approach. Ongoing studies include in vitro experiments in a larger number of samples and feasibility testing in in vivo models as well as pathological human specimens. PMID:25776065

  11. Fabrication method, structure, mechanical, and biological properties of decellularized extracellular matrix for replacement of wide bone tissue defects.

    PubMed

    Anisimova, N Y; Kiselevsky, M V; Sukhorukova, I V; Shvindina, N V; Shtansky, D V

    2015-09-01

    The present paper was focused on the development of a new method of decellularized extracellular matrix (DECM) fabrication via a chemical treatment of a native bone tissue. Particular attention was paid to the influence of chemical treatment on the mechanical properties of native bones, sterility, and biological performance in vivo using the syngeneic heterotopic and orthotopic implantation models. The obtained data indicated that after a chemical decellularization treatment in 4% aqueous sodium chlorite, no noticeable signs of the erosion of compact cortical bone surface or destruction of trabeculae of spongy bone in spinal channel were observed. The histological studies showed that the chemical treatment resulted in the decellularization of both bone and cartilage tissues. The DECM samples demonstrated no signs of chemical and biological degradation in vivo. Thorough structural characterization revealed that after decellularization, the mineral frame retained its integrity with the organic phase; however clotting and destruction of organic molecules and fibers were observed. FTIR studies revealed several structural changes associated with the destruction of organic molecules, although all organic components typical of intact bone were preserved. The decellularization-induced structural changes in the collagen constituent resulted changed the deformation under compression mechanism: from the major fracture by crack propagation throughout the sample to the predominantly brittle fracture. Although the mechanical properties of radius bones subjected to decellularization were observed to degrade, the mechanical properties of ulna bones in compression and humerus bones in bending remained unchanged. The compressive strength of both the intact and decellularized ulna bones was 125-130 MPa and the flexural strength of humerus bones was 156 and 145 MPa for the intact and decellularized samples, respectively. These results open new avenues for the use of DECM samples as

  12. Non-contact, ultrasound-based indentation method for measuring elastic properties of biological tissues using Harmonic Motion Imaging (HMI)

    NASA Astrophysics Data System (ADS)

    Vappou, Jonathan; Hou, Gary Y.; Marquet, Fabrice; Shahmirzadi, Danial; Grondin, Julien; Konofagou, Elisa E.

    2015-04-01

    Noninvasive measurement of mechanical properties of biological tissues in vivo could play a significant role in improving the current understanding of tissue biomechanics. In this study, we propose a method for measuring elastic properties non-invasively by using internal indentation as generated by harmonic motion imaging (HMI). In HMI, an oscillating acoustic radiation force is produced by a focused ultrasound transducer at the focal region, and the resulting displacements are estimated by tracking radiofrequency signals acquired by an imaging transducer. In this study, the focal spot region was modeled as a rigid cylindrical piston that exerts an oscillatory, uniform internal force to the underlying tissue. The HMI elastic modulus EHMI was defined as the ratio of the applied force to the axial strain measured by 1D ultrasound imaging. The accuracy and the precision of the EHMI estimate were assessed both numerically and experimentally in polyacrylamide tissue-mimicking phantoms. Initial feasibility of this method in soft tissues was also shown in canine liver specimens in vitro. Very good correlation and agreement was found between the measured Young’s modulus and the HMI modulus in the numerical study (r2 > 0.99, relative error <10%) and on polyacrylamide gels (r2 = 0.95, relative error <24%). The average HMI modulus on five liver samples was found to EHMI = 2.62  ±  0.41 kPa, compared to EMechTesting = 4.2  ±  2.58 kPa measured by rheometry. This study has demonstrated for the first time the initial feasibility of a non-invasive, model-independent method to estimate local elastic properties of biological tissues at a submillimeter scale using an internal indentation-like approach. Ongoing studies include in vitro experiments in a larger number of samples and feasibility testing in in vivo models as well as pathological human specimens.

  13. Non-contact, ultrasound-based indentation method for measuring elastic properties of biological tissues using harmonic motion imaging (HMI).

    PubMed

    Vappou, Jonathan; Hou, Gary Y; Marquet, Fabrice; Shahmirzadi, Danial; Grondin, Julien; Konofagou, Elisa E

    2015-04-07

    Noninvasive measurement of mechanical properties of biological tissues in vivo could play a significant role in improving the current understanding of tissue biomechanics. In this study, we propose a method for measuring elastic properties non-invasively by using internal indentation as generated by harmonic motion imaging (HMI). In HMI, an oscillating acoustic radiation force is produced by a focused ultrasound transducer at the focal region, and the resulting displacements are estimated by tracking radiofrequency signals acquired by an imaging transducer. In this study, the focal spot region was modeled as a rigid cylindrical piston that exerts an oscillatory, uniform internal force to the underlying tissue. The HMI elastic modulus EHMI was defined as the ratio of the applied force to the axial strain measured by 1D ultrasound imaging. The accuracy and the precision of the EHMI estimate were assessed both numerically and experimentally in polyacrylamide tissue-mimicking phantoms. Initial feasibility of this method in soft tissues was also shown in canine liver specimens in vitro. Very good correlation and agreement was found between the measured Young's modulus and the HMI modulus in the numerical study (r(2) > 0.99, relative error <10%) and on polyacrylamide gels (r(2) = 0.95, relative error <24%). The average HMI modulus on five liver samples was found to EHMI = 2.62  ±  0.41 kPa, compared to EMechTesting = 4.2  ±  2.58 kPa measured by rheometry. This study has demonstrated for the first time the initial feasibility of a non-invasive, model-independent method to estimate local elastic properties of biological tissues at a submillimeter scale using an internal indentation-like approach. Ongoing studies include in vitro experiments in a larger number of samples and feasibility testing in in vivo models as well as pathological human specimens.

  14. Exploiting the Physicochemical Properties of Dendritic Polymers for Environmental and Biological Applications

    SciTech Connect

    Bhattacharya, Priyanka; Geitner, Nicholas K.; Sarupria, Sapna; Ke, Pu Chun

    2013-04-07

    In this Perspective we first examine the rich physicochemical properties of dendritic polymers for hosting cations, anions, and polyaromatic hydrocarbons. We then extrapolate these conceptual discussions to the use of dendritic polymers for humic acid antifouling, oil dispersion, copper sensing, and fullerenol remediation. In addition, we review the state-of-the-art of dendrimer research and elaborate on their 10 implications for water purification, environmental remediation, nanomedicine, and energy harvesting.

  15. Biologic properties of non-antibiotic, chemically modified tetracyclines (CMTs): a structured, annotated bibliography.

    PubMed

    Greenwald, R; Golub, L

    2001-02-01

    The first paper reporting on a potentially important medical property of a non-antimicrobial tetracycline appeared in 1987. Since then, a literature of over 75 papers has supported the therapeutic potential of this class of compounds. In this review, this literature is grouped and organized with commentary on the data which has been published to date. The biomedical applicability of these discoveries obviously covers a wide range of medical conditions and clearly justifies their continued development.

  16. Plankton and particle size and packaging: from determining optical properties to driving the biological pump.

    PubMed

    Stemmann, L; Boss, E

    2012-01-01

    Understanding pelagic ecology and quantifying energy fluxes through the trophic web and from the surface to the deep ocean requires the ability to detect and identify all organisms and particles in situ and in a synoptic manner. An idealized sensor should observe both the very small living or dead particles such as picoplankton and detritus, respectively, and the large particles such as aggregates and meso- to macroplankton. Such an instrument would reveal an astonishing amount and diversity of living and nonliving particles present in a parcel of water. Unfortunately such sensors do not exist. However, complex interactions constrain the space, temporal, and size distributions of these objects in such ways that general rules can be inferred from the measurement of their optical properties. Recent technological developments allow for the in situ measurement of the optical properties and size distributions of particles and plankton in a way such that synoptic surveys are possible. This review deals with particle and plankton size distributions (PSDs) as well as how particles' geometry and nature affect their optical properties. Finally, we propose the integration of the PSD into size-structured mathematical models of biogeochemical fluxes.

  17. Improving fundamental abilities of atomic force microscopy for investigating quantitative nanoscale physical properties of complex biological systems

    NASA Astrophysics Data System (ADS)

    Cartagena-Rivera, Alexander X.

    Measurements of local material properties of complex biological systems (e.g. live cells and viruses) in their respective physiological conditions are extremely important in the fields of biophysics, nanotechnology, material science, and nanomedicine. Yet, little is known about the structure-function-property relationship of live cells and viruses. In the case of live cells, the measurements of progressive variations in viscoelastic properties in vitro can provide insight to the mechanistic processes underpinning morphogenesis, mechano-transduction, motility, metastasis, and many more fundamental cellular processes. In the case of living viruses, the relationship between capsid structural framework and the role of the DNA molecule interaction within viruses influencing their stiffness, damping and electrostatic properties can shed light in virological processes like protein subunits assembly/dissassembly, maturation, and infection. The study of mechanics of live cells and viruses has been limited in part due to the lack of technology capable of acquiring high-resolution (nanoscale, subcellular) images of its heterogeneous material properties which vary widely depending on origin and physical interaction. The capabilities of the atomic force microscope (AFM) for measuring forces and topography with sub-nm precision have greatly contributed to research related to biophysics and biomechanics during the past two decades. AFM based biomechanical studies have the unique advantage of resolving/mapping spatially the local material properties over living cells and viruses. However, conventional AFM techniques such as force-volume and quasi-static force-distance curves are too low resolution and low speed to resolve interesting biophysical processes such as cytoskeletal dynamics for cells or assembly/dissasembly of viruses. To overcome this bottleneck, a novel atomic force microscopy mode is developed, that leads to sub-10-nm resolution and sub-15-minutes mapping of local

  18. Physicochemical properties of crystalline silica dusts and their possible implication in various biological responses.

    PubMed

    Fubini, B; Bolis, V; Cavenago, A; Volante, M

    1995-01-01

    The effect of grinding, heating, and etching was investigated on polymorphs of silicon dioxide exhibiting different biological responses. Diatomaceous earths were converted into cristobalite at 1000 degrees C. Dusts obtained by grinding crystalline minerals exhibited different micromorphology and a propensity to originate surface radicals which decrease in the sequence cristobalite --> quartz --> coesite --> stishovite. The production of surface radicals was suppressed by grinding in the presence of water. Thermal treatments selectively quenched the radicals and decreased surface hydrophilicity. Quartz treated with aluminum lactate exhibited higher surface acidity when compared with pure quartz, with a reduction in fibrogenicity. Etching by hydrofluoric acid smoothed the particles with loss of specific surface. Adsorption of water on three cristobalite dusts of different origin (ground mineral, ex-diatomite, heated quartz) indicated a loss in heated quartz (1300 degrees C) that was relatable to the corresponding reduction in fibrogenicity.

  19. Mars primordial crust: unique sites for investigating proto-biologic properties.

    PubMed

    Perry, Randall S; Hartmann, William K

    2006-12-01

    The Martian meteorite collection suggests that intact outcrops or boulder-scale fragments of the 4.5 Ga Martian crust exist within tens of meters of the present day surface of Mars. Mars may be the only planet where such primordial crust samples, representing the first 100 Ma of a planet's environment, are available. The primordial crust has been destroyed on Earth by plate tectonics and other geological phenomena and is buried on the Moon under hundreds or thousands of meters of megaregoltih. Early Mars appears to have been remarkably similar to early Earth, and samples of rock from the first few Ma or first 100 Ma may reveal "missing link" proto-biological forms that could shed light on the transition from abiotic organic chemistry to living cells. Such organic snapshots of nascent life are unlikely to be found on Earth.

  20. Investigation on biological properties of tacrolimus-loaded poly(1,3-trimethylene carbonate) in vitro

    NASA Astrophysics Data System (ADS)

    Hou, Ruixia; Wu, Leigang; Wang, Jin; Huang, Nan

    2010-06-01

    The drug-eluting stents have been regarded as a milestone in inhibiting the restenosis of coronary arteries. However, adverse reactions caused by bare-metal stents and non-biodegradable polymer coatings may result in some clinical problems. In this study, a new tacrolimus-eluting stent coated with biodegradable poly(1,3-trimethylene carbonate) (PTMC) is developed. The structures are characterized by Fourier transform infrared (FTIR) analysis, and the wettability is measured by contact angle assay. The biological behaviors are evaluated by the in vitro platelets adhesion test, APTT test, the human umbilical cord artery smooth muscle cells (HUCASMCs), 4',6-diamidine-2-phenylindole (DAPI) and actin immunofluorescence staining, MTT colorimetric assay. These results show that after blending tacrolimus into PTMC, the anticoagulant behavior is improved, and the adhesion and proliferation of HUCASMCs on samples are inhibited. This work aims to find one kind of surface erosion biodegradable polymers that can be applied as drug-eluting stent coatings.

  1. (/sup 125/I)diiodoinsulins. Binding affinities, biologic potencies, and properties of their decay products

    SciTech Connect

    Perez Maceda, B.; Linde, S.; Sonne, O.; Gliemann, J.

    1982-07-01

    Insulin was iodinated with 0.3-0.4 mol /sup 125/I/mol insulin using the lactoperoxidase method. About one-third of the radioactivity incorporated into insulin was in diiodoinsulins and about 40% of these molecules contained diiodotyrosine in residue 14 of the A chain. Most of the remaining molecules contained one A14-monoiodotyrosine and one monoiodotyrosine in either position A19, B16, or B26. The binding affinity and biologic potency of this heterogeneous diiodoinsulin preparation was not significantly different from that of A14-(/sup 125/I)monoiodoinsulin in rat adipocytes, whereas it was slightly reduced in hepatocytes and IM-9 lymphocytes. From the iodine distribution and previous data on the binding affinity of each of the four monoiodoinsulin isomers it was calculated that A14-diiodotyrosine-insulin possesses full binding affinity and biologic potency in adipocytes. Diiodoinsulins isolated from another iodoinsulin preparation (iodate method) contained 58% A19-diiodotyrosine-insulin, and most remaining molecules contained one A19-monoiodotyrosine. The binding affinity of this mixed diiodoinsulin preparation was approximately one-fourth of that of A14-monoiodoinsulin in adipocytes, IM-9 lymphocytes, and hepatocytes. It was calculated that A19-diiodotyrosine-insulin is nearly devoid of binding affinity. The diiodoinsulins (lactoperoxidase method) decayed to iodide (probably from diiodotyrosine-insulin) or to polymers with little specific but a markedly increased nonspecific binding. In addition, the polymers had a marked tendency to adsorb to cellulose acetate filters. Conclusions: 1. The binding affinities of diiodoinsulins range from very low values to values at least as high as that of insulin depending on the positions of the iodine moieties. 2. The relative binding affinities vary among tissues. 3. Polymeric decay products give high nonspecific binding.

  2. Thermodynamic nonequilibrium phase change behavior and thermal properties of biological solutions for cryobiology applications.

    PubMed

    Han, Bumsoo; Bischof, John C

    2004-04-01

    Understanding the phase change behavior of biomaterials during freezing/thawing including their thermal properties at low temperatures is essential to design and improve cryobiology applications such as cryopreservation and cryosurgery. However, knowledge of phase change behavior and thermal properties of various biomaterials is still incomplete, especially at cryogenic temperatures (< or = -40 degrees C). Moreover, in these applications, chemicals are often added to improve their outcome, which can result in significant variation in the phase change behavior and thermal properties from those of the original biomaterials. These chemical additives include cryoprotective agents (CPAs), antifreeze protein (AFP), or cryosurgical adjuvants like sodium chloride (NaCl). In the present study, phase change behavior and thermal properties of saline solutions--either water-NaCl or phosphate buffered saline (PBS)--with various chemical additives were investigated. The chemical additives studied are glycerol and raffinose as CPAs, an AFP (Type III, molecular weight = 6500), and NaCl as a cryosurgical adjuvant. The phase change behavior was investigated using a differential scanning calorimeter (DSC) and a cryomicroscope. The specific and latent heat of these solutions were also measured with the DSC. The saline solutions have two distinct phase changes--water/ice and eutectic phase changes. During freezing, eutectic solidification of both water-NaCl and PBS are significantly supercooled below their thermodynamic equilibrium eutectic temperatures. However, their melting temperatures are close to thermodynamic equilibrium during thawing. These eutectic phase changes disappear when even a small amount (0.1 M glycerol) of CPA was added, but they are still observed after the addition of an AFP. The specific heats of these solutions are close to that of ice at very low temperatures (< or = -100 degrees C) regardless of the additives, but they increase between -100 degrees C and -30

  3. BioCompoundML: A General Biofuel Property Screening Tool for Biological Molecules Using Random Forest Classifiers

    DOE PAGES

    Whitmore, Leanne S.; Davis, Ryan W.; McCormick, Robert L.; ...

    2016-09-15

    Screening a large number of biologically derived molecules for potential fuel compounds without recourse to experimental testing is important in identifying understudied yet valuable molecules. Experimental testing, although a valuable standard for measuring fuel properties, has several major limitations, including the requirement of testably high quantities, considerable expense, and a large amount of time. This paper discusses the development of a general-purpose fuel property tool, using machine learning, whose outcome is to screen molecules for desirable fuel properties. BioCompoundML adopts a general methodology, requiring as input only a list of training compounds (with identifiers and measured values) and a listmore » of testing compounds (with identifiers). For the training data, BioCompoundML collects open data from the National Center for Biotechnology Information, incorporates user-provided features, imputes missing values, performs feature reduction, builds a classifier, and clusters compounds. BioCompoundML then collects data for the testing compounds, predicts class membership, and determines whether compounds are found in the range of variability of the training data set. We demonstrate this tool using three different fuel properties: research octane number (RON), threshold soot index (TSI), and melting point (MP). Here we provide measures of its success with these properties using randomized train/test measurements: average accuracy is 88% in RON, 85% in TSI, and 94% in MP; average precision is 88% in RON, 88% in TSI, and 95% in MP; and average recall is 88% in RON, 82% in TSI, and 97% in MP. The receiver operator characteristics (area under the curve) were estimated at 0.88 in RON, 0.86 in TSI, and 0.87 in MP. We also measured the success of BioCompoundML by sending 16 compounds for direct RON determination. Finally, we provide a screen of 1977 hydrocarbons/oxygenates within the 8696 compounds in MetaCyc, identifying compounds with high

  4. Optimization and biological evaluation of celastrol derivatives as Hsp90-Cdc37 interaction disruptors with improved druglike properties.

    PubMed

    Jiang, Fen; Wang, Hui-Jie; Bao, Qi-Chao; Wang, Lei; Jin, Yu-Hui; Zhang, Qiong; Jiang, Di; You, Qi-Dong; Xu, Xiao-Li

    2016-11-01

    Heat shock protein 90 (Hsp90) as a molecular target for oncology therapeutics has attracted much attention in the last decade. The Hsp90 multichaperone complex has important roles in the growth and/or survival of cancer cells. Cdc37, as a cochaperone, associates kinase clients to Hsp90 and promotes the development of malignant tumors. Disrupting the Hsp90-Cdc37 interaction provides an alternative strategy to inhibit the function of Hsp90 for cancer therapy. Celastrol, as a natural product, can disrupt the Hsp90-Cdc37 interaction and induce degradation of kinase clients. The study conducted here attempted to elucidate the structure-activity relationship of celastrol derivatives as Hsp90-Cdc37 disruptors and to improve the druglike properties. 23 celastrol derivatives were designed, synthesized, and the biological activities and physicochemical properties were determined. The derivative CEL20 showed improved Hsp90-Cdc37 disruption activity, anti-proliferative activities as well as druglike properties. Additionally, CEL20 induced clients degradation, cell cycle arrest and apoptosis in Panc-1 cells. This study can provide reference for the discovery of novel Hsp90-Cdc37 disruptors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Chitosan as a Biomaterial: Influence of Degree of Deacetylation on Its Physiochemical, Material and Biological Properties

    PubMed Central

    Foster, Leslie John Ray; Ho, Sonia; Hook, James; Basuki, Monica; Marçal, Helder

    2015-01-01

    Chitosan is a biomaterial with a range of current and potential biomedical applications. Manipulation of chitosan degree of deacetylation (DDA) to achieve specific properties appears feasible, but studies investigating its influence on properties are often contradictory. With a view to the potential of chitosan in the regeneration of nerve tissue, the influence of DDA on the growth and health of olfactory ensheathing cells (OECs) was investigated. There was a linear increase in OEC proliferation as the DDA increased from 72 to 85%. This correlated with linear increases in average surface roughness (0.62 to 0.78 μm) and crystallinity (4.3 to 10.1%) of the chitosan films. Mitochondrial activity and membrane integrity of OECs was significantly different for OECs cultivated on chitosan with DDAs below 75%, while those on films with DDAs up to 85% were similar to cells in asynchronous growth. Apoptotic indices and cell cycle analysis also suggested that chitosan films with DDAs below 75% were cytocompatible but induced cellular stress, while OECs grown on films fabricated from chitosan with DDAs above 75% showed no significant differences compared to those in asynchronous growth. Tensile strength and elongation to break varied with DDA from 32.3 to 45.3 MPa and 3.6 to 7.1% respectively. DDA had no significant influence on abiotic and biotic degradation profiles of the chitosan films which showed approximately 8 and 20% weight loss respectively. Finally, perceived patterns in property changes are subject to change based on potential variations in DDA analysis. NMR examination of the chitosan samples here revealed significant differences depending upon which peaks were selected for integration; 6 to 13% in DDA values within individual samples. Furthermore, differences between DDA values determined here and those reported by the commercial suppliers were significant and this may also be a source of concern when selecting commercial chitosans for biomaterial research. PMID

  6. Fine structure and optical properties of biological polarizers in crustaceans and cephalopods

    NASA Astrophysics Data System (ADS)

    Chiou, Tsyr-Huei; Caldwell, Roy L.; Hanlon, Roger T.; Cronin, Thomas W.

    2008-04-01

    The lighting of the underwater environment is constantly changing due to attenuation by water, scattering by suspended particles, as well as the refraction and reflection caused by the surface waves. These factors pose a great challenge for marine animals which communicate through visual signals, especially those based on color. To escape this problem, certain cephalopod mollusks and stomatopod crustaceans utilize the polarization properties of light. While the mechanisms behind the polarization vision of these two animal groups are similar, several distinctive types of polarizers (i.e. the structure producing the signal) have been found in these animals. To gain a better knowledge of how these polarizers function, we studied the relationships between fine structures and optical properties of four types of polarizers found in cephalopods and stomatopods. Although all the polarizers share a somewhat similar spectral range, around 450- 550 nm, the reflectance properties of the signals and the mechanisms used to produce them have dramatic differences. In cephalopods, stack-plates polarizers produce the polarization patterns found on the arms and around their eyes. In stomatopods, we have found one type of beam-splitting polarizer based on photonic structures and two absorptive polarizer types based on dichroic molecules. These stomatopod polarizers may be found on various appendages, and on the cuticle covering dorsal or lateral sides of the animal. Since the efficiencies of all these polarizer types are somewhat sensitive to the change of illumination and viewing angle, how these animals compensate with different behaviors or fine structural features of the polarizer also varies.

  7. Effects of proanthocyanidin, a crosslinking agent, on physical and biological properties of collagen hydrogel scaffold

    PubMed Central

    Choi, Yoorina; Kim, Hee-Jin

    2016-01-01

    Objectives The purpose of the present study was to evaluate the effects of proanthocyanidin (PAC), a crosslinking agent, on the physical properties of a collagen hydrogel and the behavior of human periodontal ligament cells (hPDLCs) cultured in the scaffold. Materials and Methods Viability of hPDLCs treated with PAC was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The physical properties of PAC treated collagen hydrogel scaffold were evaluated by the measurement of setting time, surface roughness, and differential scanning calorimetry (DSC). The behavior of the hPDLCs in the collagen scaffold was evaluated by cell morphology observation and cell numbers counting. Results The setting time of the collagen scaffold was shortened in the presence of PAC (p < 0.05). The surface roughness of the PAC-treated collagen was higher compared to the untreated control group (p < 0.05). The thermogram of the crosslinked collagen exhibited a higher endothermic peak compared to the uncrosslinked one. Cells in the PAC-treated collagen were observed to attach in closer proximity to one another with more cytoplasmic extensions compared to cells in the untreated control group. The number of cells cultured in the PAC-treated collagen scaffolds was significantly increased compared to the untreated control (p < 0.05). Conclusions Our results showed that PAC enhanced the physical properties of the collagen scaffold. Furthermore, the proliferation of hPDLCs cultured in the collagen scaffold crosslinked with PAC was facilitated. Conclusively, the application of PAC to the collagen scaffold may be beneficial for engineering-based periodontal ligament regeneration in delayed replantation. PMID:27847751

  8. Chitosan as a Biomaterial: Influence of Degree of Deacetylation on Its Physiochemical, Material and Biological Properties.

    PubMed

    Foster, Leslie John Ray; Ho, Sonia; Hook, James; Basuki, Monica; Marçal, Helder

    2015-01-01

    Chitosan is a biomaterial with a range of current and potential biomedical applications. Manipulation of chitosan degree of deacetylation (DDA) to achieve specific properties appears feasible, but studies investigating its influence on properties are often contradictory. With a view to the potential of chitosan in the regeneration of nerve tissue, the influence of DDA on the growth and health of olfactory ensheathing cells (OECs) was investigated. There was a linear increase in OEC proliferation as the DDA increased from 72 to 85%. This correlated with linear increases in average surface roughness (0.62 to 0.78 μm) and crystallinity (4.3 to 10.1%) of the chitosan films. Mitochondrial activity and membrane integrity of OECs was significantly different for OECs cultivated on chitosan with DDAs below 75%, while those on films with DDAs up to 85% were similar to cells in asynchronous growth. Apoptotic indices and cell cycle analysis also suggested that chitosan films with DDAs below 75% were cytocompatible but induced cellular stress, while OECs grown on films fabricated from chitosan with DDAs above 75% showed no significant differences compared to those in asynchronous growth. Tensile strength and elongation to break varied with DDA from 32.3 to 45.3 MPa and 3.6 to 7.1% respectively. DDA had no significant influence on abiotic and biotic degradation profiles of the chitosan films which showed approximately 8 and 20% weight loss respectively. Finally, perceived patterns in property changes are subject to change based on potential variations in DDA analysis. NMR examination of the chitosan samples here revealed significant differences depending upon which peaks were selected for integration; 6 to 13% in DDA values within individual samples. Furthermore, differences between DDA values determined here and those reported by the commercial suppliers were significant and this may also be a source of concern when selecting commercial chitosans for biomaterial research.

  9. Chemical properties and biological activity of a polysaccharide from Melocactus depressus.

    PubMed

    da Silva, Bernadete P; Parente, José P

    2002-01-01

    An arabinogalactan with mean Mr of 6.85 x 10(4), was isolated from the pulps of Melocactus depressus Hook by fractionation on Sephacryl S-300 HR. Chemical and spectroscopic studies indicated that it has a branched arabinogalactan type structure composed of beta-(1-->4) linked D-galactopyranose residues with beta-(1-->3) and beta-(1-->6) branching points. Its structural features include also alpha-(1-->2), alpha-(1-->3) and alpha-(1-->5) linked L-arabinofuranose residues. The polysaccharide demonstrated a phagocytosis stimulating property.

  10. Influence of Space-Flight Factors on the Properties of Microorganisms, Producers of Biologically Active Substances

    NASA Astrophysics Data System (ADS)

    Krasheninnikova, T. K.; Kanaeva, E. N.; Ukraintsev, A. D.; Smolyanaya, G. L.; Kuznetsov, N. V.; Panasyuk, M. I.; Shcherbakov, G. Ya.

    2001-07-01

    The following substances were isolated under the influence of space-flight factors in cosmic experiments aboard the Mirorbital station: an MIB-90 monoisolant, which is distinguished by its morphological and biochemical properties and enhanced productivity, was isolated from the Bacillus thuringiensis ssp. Kurstaki var. Z-52culture, which is a producer of the plant protection agent Lepidocide; and MIA-74 and MIP-89 monoisolants, which are highly active toward heavy petroleum fractions (C23 C33), were isolated from the Arthrobacter OC-1culture, which is a producer of biodegradants for petroleum.

  11. Nonlinear electric properties in biological system for stochastic computing (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sumida, Saki; Yamaguchi, Harumasa; Ohyama, Hiroshi; Otsuka, Yoichi; Che, Dock-Chil; Matsumoto, Takuya

    2016-09-01

    Nonlinearity is the vital factor for stochastic computing. Toward the realization of brain-mimetic function using molecular network, the nonlinear electric properties of molecular systems are investigated in nanoscale with atomic force microscopy and nano-gap electrodes. Nonlinear current-voltage characteristics were observed for {Mo154/152}-ring, cytochorome c, and cytochrome c/DNA networks where the conduction paths include electron injection into weakly coupled discrete energy levels, electron tunneling through potential well, and electron hopping via Coulomb-blockade network. Stochastic resonance was observed in Cytochrome c/DNA network.

  12. Synthesis of antisense oligonucleotides containing acyclic alkynyl nucleoside analogs and their biophysical and biological properties.

    PubMed

    Ogata, Aya; Maeda, Yusuke; Ueno, Yoshihito

    2017-04-01

    The synthesis of oligonucleotide (ON) analogs, which can be used as antisense molecules, has recently gained much attention. Here, we report the synthesis and properties of an ON analog containing acyclic thymidine and cytidine analogs with a 4-pentyl-1,2-diol instead of the d-ribofuranose moiety. The incorporation of these analogs into the ON improved its nuclease resistance to 3'-exonucleases. Furthermore, it was found that the incorporation of the acyclic thymidine analog into a DNA/RNA duplex accelerates the RNA cleavage of a DNA/RNA duplex by Escherichia coli RNase H.

  13. Studies of biological properties of Uncaria tomentosa extracts on human blood mononuclear cells.

    PubMed

    Bors, Milena; Michałowicz, Jaromir; Pilarski, Radosław; Sicińska, Paulina; Gulewicz, Krzysztof; Bukowska, Bożena

    2012-08-01

    Uncaria tomentosa (Willd.) DC is a lignified climbing plant from South and Central America, which (under the name of "vilcacora" or "cat's claw") has become highly popular in many countries due to its proven immunostimmulatory and anti-inflammatory activities and also with respect to its anticancer and antioxidative effects. There are insufficient data on the mechanism of U. tomentosa action on normal blood mononuclear cells. The aim of the study was to analyze the impact of ethanol and aqueous extracts from bark and leaves of Uncaria tomentosa on the structure and function of human mononuclear cells and to find out whether the kind of extractant used modulates biological activity of the extracts studied. Plant material consisted of four different extracts: (1) ethanol extract from leaves, (2) aqueous extract from leaves, (3) ethanol extract from bark and (4) aqueous extract from bark. The effect of these extracts on protein damage as well as on free-radical formation in human peripheral blood mononuclear cells was analyzed. Moreover, changes in viability, size, and granularity as well as apoptotic alterations in human blood mononuclear cells exposed to U. tomentosa extracts were investigated. The oxidative changes were observed in mononuclear blood cells exposed to both ethanol and aqueous extracts obtained from bark and leaves. Moreover, in the cells studied the extracts from U. tomentosa induced apoptosis and a decrease in viability of mononuclear blood cells, with the exception of aqueous extract from leaves. Additionally, no statistically significant changes in the cell size were observed both for aqueous extracts from leaves and bark. Changes in the blood mononuclear cell granularity were observed at 250 μg/mL for all extracts examined. The strongest changes were observed for the ethanol extract of the bark, which increased cell granularity at 50 μg/mL and changed cell size at 100 μg/mL. The conducted research showed differences in biological activity

  14. A Monte-Carlo maplet for the study of the optical properties of biological tissues

    NASA Astrophysics Data System (ADS)

    Yip, Man Ho; Carvalho, M. J.

    2007-12-01

    Monte-Carlo simulations are commonly used to study complex physical processes in various fields of physics. In this paper we present a Maple program intended for Monte-Carlo simulations of photon transport in biological tissues. The program has been designed so that the input data and output display can be handled by a maplet (an easy and user-friendly graphical interface), named the MonteCarloMaplet. A thorough explanation of the programming steps and how to use the maplet is given. Results obtained with the Maple program are compared with corresponding results available in the literature. Program summaryProgram title:MonteCarloMaplet Catalogue identifier:ADZU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.:3251 No. of bytes in distributed program, including test data, etc.:296 465 Distribution format: tar.gz Programming language:Maple 10 Computer: Acer Aspire 5610 (any running Maple 10) Operating system: Windows XP professional (any running Maple 10) Classification: 3.1, 5 Nature of problem: Simulate the transport of radiation in biological tissues. Solution method: The Maple program follows the steps of the C program of L. Wang et al. [L. Wang, S.L. Jacques, L. Zheng, Computer Methods and Programs in Biomedicine 47 (1995) 131-146]; The Maple library routine for random number generation is used [Maple 10 User Manual c Maplesoft, a division of Waterloo Maple Inc., 2005]. Restrictions: Running time increases rapidly with the number of photons used in the simulation. Unusual features: A maplet (graphical user interface) has been programmed for data input and output. Note that the Monte-Carlo simulation was programmed with Maple 10. If attempting to run the simulation with an earlier version of Maple

  15. Divalent Amino-Acid-Based Amphiphilic Antioxidants: Synthesis, Self-Assembling Properties, and Biological Evaluation.

    PubMed

    Rosselin, Marie; Meyer, Grégory; Guillet, Pierre; Cheviet, Thomas; Walther, Guillaume; Meister, Annette; Hadjipavlou-Litina, Dimitra; Durand, Grégory

    2016-03-16

    We report herein the synthesis of a divalent amphiphilic carrier onto which α-phenyl-N-tert-butyl nitrone (PBN) and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) antioxidants were grafted to give the divalent derivative called FATxPBN. The divalent carrier consists of two lysine amino acids as a scaffold upon which the antioxidant moieties are grafted, a perfluorinated chain that supplies hydrophobicity, and a sugar-based polar headgroup that ensures water solubility. For the sake of comparison, a divalent PBN derivative called FADiPBN was also synthesized. The self-aggregation properties of FATxPBN and FADiPBN were studied by means of surface tension, dynamic light scattering, and transmission electron microscopy methods, and showed they form small micelles (i.e., 12 and 6 nm diameter, respectively) at submillimolar concentrations (i.e., 0.01 and 0.05 mM, respectively), in agreement with partition coefficient values. The superior antioxidant properties of FATxPBN over FADiPBN and the parent compounds PBN and Trolox were demonstrated using in vitro ABTS(•+) reduction (98%) and soybean lipoxygenase inhibition (94%) assays. Finally, FATxPBN was found to significantly inhibit hyperglycemia-induced toxicity on an ex-vivo rat model, demonstrating its potency as a bioactive antioxidant against oxidative stress-induced damage.

  16. Polyurethane anionomers containing metal ions with antimicrobial properties: thermal, mechanical and biological characterization.

    PubMed

    Francolini, I; D'Ilario, L; Guaglianone, E; Donelli, G; Martinelli, A; Piozzi, A

    2010-09-01

    In recent years the employment of implantable medical devices has increased remarkably, notwithstanding that microbial infections are a frequent complication associated with their use. Different strategies have been attempted to overcome this problem, including the incorporation of antimicrobial agents into the device itself. In this study a new approach to obtain intrinsically antimicrobial materials was developed. Polymer anionomers containing Ag(I), Cu(II), Zn(II), Al(III) and Fe(III) were prepared by neutralization of a carboxylated polyurethane. In the case of the PEUA-Ag, PEUA-Fe and PEUA-Cu ionomers the ion aggregates behaved as reinforcing filler particles, increasing the mechanical properties of the systems in terms of hardness and strength at break over the pristine carboxylated polymer. With the exception of the Al-containing polymer, all the other experimented ionomers showed satisfactory antimicrobial properties. The best antibacterial effect was obtained with the silver ion-containing polymer, which inhibited Staphylococcus epidermidis growth for up to 16days. Ciprofloxacin was also adsorbed onto the above mentioned ionomers. A synergistic effect of the antibiotic and silver ions on bacterial growth inhibition was observed for at least 25days. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  17. Physicochemical, mechanical, and biological properties of bone cements prepared with functionalized methacrylates.

    PubMed

    Sabino, Marco A; Ajami, Diana; Salih, Vehid; Nazhat, Showan N; Vargas-Coronado, Rossana; Cauich-Rodríguez, Juan V; Ginebra, Ma Pau

    2004-10-01

    Bone cements prepared with methyl methacrylate (MMA) as a base monomer and either methacrylic acid (MAA) or diethyl amino ethyl methacrylate (DEAEMA) as comonomers were characterized in terms of curing behavior, mechanical properties, and their in vitro biocompatibility. The curing time and setting temperature were found to be composition dependent while the residual monomer was not greatly affected by the presence of either acidic or alkaline comonomers in the bone cements. For samples with MAA comonomer, a faster curing time and higher setting temperature were observed when compared to the cement with DEAEMA comonomer. In terms of mechanical properties, the highest compressive strength was exhibited by formulations containing MAA, while the highest impact strength was shown by the formulations prepared with DEAEMA. There were no differences observed between the two formulations for tensile, shear, and bending strength values. Similarly, fatigue crack propagation studies did not reveal differences with the addition of either DEAEMA or MAA.No differences were observed in the initial number of attached primary rat femur osteoblasts on the different bone cements and positive controls. However, after 48 h there was a reduced proliferation in the cells grown on bone cements containing MAA.

  18. Biological and surface-active properties of double-chain cationic amino acid-based surfactants.

    PubMed

    Greber, Katarzyna E; Dawgul, Małgorzata; Kamysz, Wojciech; Sawicki, Wiesław; Łukasiak, Jerzy

    2014-08-01

    Cationic amino acid-based surfactants were synthesized via solid phase peptide synthesis and terminal acylation of their α and ε positions with saturated fatty acids. Five new lipopeptides, N-α-acyl-N-ε-acyl lysine analogues, were obtained. Minimum inhibitory concentration and minimum bactericidal (fungicidal) concentration were determined on reference strains of bacteria and fungi to evaluate the antimicrobial activity of the lipopeptides. Toxicity to eukaryotic cells was examined via determination of the haemolytic activities. The surface-active properties of these compounds were evaluated by measuring the surface tension and formation of micelles as a function of concentration in aqueous solution. The cationic surfactants demonstrated diverse antibacterial activities dependent on the length of the fatty acid chain. Gram-negative bacteria and fungi showed a higher resistance than Gram-positive bacterial strains. It was found that the haemolytic activities were also chain length-dependent values. The surface-active properties showed a linear correlation between the alkyl chain length and the critical micelle concentration.

  19. Water-soluble polysaccharides from agro-industrial by-products: functional and biological properties.

    PubMed

    Sila, Assaâd; Bayar, Nadia; Ghazala, Imen; Bougatef, Ali; Ellouz-Ghorbel, Raoudha; Ellouz-Chaabouni, Semia

    2014-08-01

    Water-soluble polysaccharides were isolated from almond (AWSP) and pistachio (PWSP) juice processing by-products. Their chemical and physical characteristics were determined using NMR and Infrared spectroscopic analysis. The complexities of the spectra reflected the heterogeneity of these polysaccharides. The ACE inhibitory activities (IC50 AWSP=2.81mgmL(-1) and IC50 PWSP=2.59mgmL(-1)) and antioxidant properties of AWSP and PWSP were investigated based on the DPPH radical-scavenging capacity assay (IC50 AWSP=2.87mgmL(-1) and IC50 PWSP=1.61mgmL(-1)). Reducing power, β-carotene bleaching inhibition (IC50AWSP=4.46mgmL(-1) and IC50 PWSP=3.39mgmL(-1)), and ferrous chelating assays (IC50 AWSP=0.22mgmL(-1) and IC50 PWSP=0.19mgmL(-1)) were also performed. The findings revealed that water-soluble polysaccharides exhibited antioxidant and antihypertensive activities. AWSP and PWSP showed excellent interfacial concentration-dependent properties. Overall, the results suggested that both AWSP and PWSP are promising sources of natural antioxidants and ACE inhibitory agents and could, therefore, be used as alternative additives in food, pharmaceutical and cosmetic preparations.

  20. Physicochemical and biological properties of a novel injectable polyurethane system for root canal filling

    PubMed Central

    Wang, Jian; Zuo, Yi; Zhao, Minghui; Jiang, Jiaxing; Man, Yi; Wu, Jun; Hu, Yunjiu; Liu, Changlei; Li, Yubao; Li, Jidong

    2015-01-01

    A root canal sealer with antibacterial activity can be efficacious in preventing reinfection that results from residual microorganisms and/or the leakage of microorganisms. In the present study, a series of injectable, self-curing polyurethane (PU)-based antibacterial sealers with different concentrations of silver phosphate (Ag3PO4) were fabricated. Subsequently, their physicochemical properties, antibacterial abilities, and preliminary cytocompatibilities were evaluated. The results indicated that the fabricated PU-based sealers can achieve a high conversion rate in a short amount of time. More than 95% of the isocyanate group of PU sealers with 3 wt% (PU3) and 5 wt% (PU5) concentrations of Ag3PO4 were included in the curing reaction after 7 hours. With the exception of those for film thickness for PU5, the results of setting time, film thickness, and solubility were able to meet the requirements of the International Organization for Standardization. The antibacterial tests showed that PU3 and PU5 exhibit stronger antimicrobial effects than that achieved with 1 wt% Ag3PO4 (PU1) and AH Plus (positive control) against Streptococcus mutans. The cytocompatibility evaluation revealed that the PU1 and PU3 sealers possess good cytocompatibility and low cytotoxicity. These results demonstrate that the PU3 sealer offers good physicochemical and antimicrobial properties along with cytocompatibility, which may hold great application potential in the field of root canal fillings. PMID:25653518

  1. The Investigation of Property of Radiation and Absorbed of Infrared Lights of the Biological Tissues

    NASA Astrophysics Data System (ADS)

    Pang, Xiao-Feng; Deng, Bo; Xiao, He-Lan; Cai, Guo-Ping

    2010-04-01

    The properties of absorption of infrared light for collagen, hemoglobin, bivine serum albumen (BSA) protein molecules with α- helix structure and water in the living systems as well as the infrared transmission spectra for person’s skins and finger hands of human body in the region of 400-4000 cm-1 (i.e., wavelengths of 2-20 μm) have been collected and determined by using a Nicolet Nexus 670 FT-IR Spectrometer, a Perkin Elmer GX FT-IR spectrometer, an OMA (optical multichannel analysis) and an infrared probe systems, respectively. The experimental results obtained show that the protein molecules and water can all absorb the infrared lights in the ranges of 600-1900 cm-1 and 2900-3900 cm-l, but their properties of absorption are somewhat different due to distinctions of their structure and conformation and molecular weight. We know from the transmission spectra of person’s finger hands and skin that the infrared lights with wavelengths of 2 μm-7 μm can not only transmit over the person’s skin and finger hands, but also be absorbed by the above proteins and water in the living systems. Thus, we can conclude from this study that the human beings and animals can absorb the infrared lights with wavelengths of 2 μm-7 μm.

  2. A new computational strategy for identifying essential proteins based on network topological properties and biological information.

    PubMed

    Qin, Chao; Sun, Yongqi; Dong, Yadong

    2017-01-01

    Essential proteins are the proteins that are indispensable to the survival and development of an organism. Deleting a single essential protein will cause lethality or infertility. Identifying and analysing essential proteins are key to understanding the molecular mechanisms of living cells. There are two types of methods for predicting essential proteins: experimental methods, which require considerable time and resources, and computational methods, which overcome the shortcomings of experimental methods. However, the prediction accuracy of computational methods for essential proteins requires further improvement. In this paper, we propose a new computational strategy named CoTB for identifying essential proteins based on a combination of topological properties, subcellular localization information and orthologous protein information. First, we introduce several topological properties of the protein-protein interaction (PPI) network. Second, we propose new methods for measuring orthologous information and subcellular localization and a new computational strategy that uses a random forest prediction model to obtain a probability score for the proteins being essential. Finally, we conduct experiments on four different Saccharomyces cerevisiae datasets. The experimental results demonstrate that our strategy for identifying essential proteins outperforms traditional computational methods and the most recently developed method, SON. In particular, our strategy improves the prediction accuracy to 89, 78, 79, and 85 percent on the YDIP, YMIPS, YMBD and YHQ datasets at the top 100 level, respectively.

  3. Mechanical properties of complex biological systems using AFM-based force spectroscopy

    NASA Astrophysics Data System (ADS)

    Graham, John Stephen

    An atomic force microscope (AFM) was designed and built to study the mechanical properties of small collagen fibrils and the plasma membrane of living cells. Collagen is a major component of bone, skin and connective tissues, and is abundant in the extracellular matrix (ECM). Because of its abundance, an understanding of how disease affects collagen mechanics is crucial in disease prevention efforts. Two levels of type I collagen structure were investigated, subfibrils (on the order of 1 mum in length) and longer fibrils. Comparisons were made between measurements of wild-type (wt) collagen and collagen from the mouse model of osteogenesis imperfecta (OI). Significant differences between OI and wt collagen were observed, primarily that intermolecular bonds in OI collagen fibrils are weaker than in wt, or not ruptured, as in the case of OI subfibrils. As cells interact with collagen in the ECM, the mechanical properties of the plasma membrane are also of great interest. Membrane tethers were extracted from living cells under varied conditions in order to assess the contributions of membrane-associated macromolecules such as the actin cytoskeleton and the glycocalyx, and intracellular signaling. Tether extraction force was found to be sensitive to all of these altered conditions, suggesting that tether extraction may be used to monitor various cellular processes.

  4. Prediction of biological protein-protein interactions using atom-type and amino acid properties.

    PubMed

    Aziz, Md Mominul; Maleki, Mina; Rueda, Luis; Raza, Mohammad; Banerjee, Sridip

    2011-10-01

    Identification and analysis of types of biological protein-protein interactions and their interfaces to predict obligate and non-obligate complexes is a problem that has drawn the attention of the research community in the past few years. In this paper, we propose a prediction approach to predict these two types of complexes. We use desolvation energies - amino acid and atom type - of the residues present in the interface. The prediction is performed via two state-of-the-art classification techniques, namely linear dimensionality reduction (LDR) and support vector machines (SVM). The results on a newly compiled data set, namely BPPI, which is a joint and modified version of two well-known data sets consisting of 213 obligate and 303 non-obligate complexes, show that the best prediction is achieved with SVM (76.94% accuracy) when using desolvation energies of atom-type features. Also, the proposed approach outperforms the previous solvent accessible area-based approaches using SVM (75% accuracy) and LDR (73.06% accuracy). Moreover, a visual analysis of desolvation energies in obligate and non-obligate complexes shows that a few atom-type pairs are good descriptors for these types of complexes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Age-dependence of molecular and functional changes in biological membrane properties.

    PubMed

    Hegner, D

    1980-01-01

    Some general aspects including results on the possible mechanisms of membrane ageing are reviewed. The liquid-crystalline fluid state of a biological membrane is an essential condition for maintenance of different membrane functions. The liquid-crystalline state of different plasma membranes changes with age of the organism. The degree of unsaturated fatty acids decreases and the content of cholesterol increases during ageing. It could be shown that superoxide radicals originate from minor side-reactions of oxidoreductase enzymes. Ageing increases the amount of superoxide radicals. A small amount of radicals escape quenching by superoxide dismutase. The formation of radicals leads to degradation of membrane lipids. The age-dependent changes in membrane lipid composition influence respiratory activity in rat heart mitochondria of old animals. Rat liver plasma membrane lipids also show a decrease in membrane fluidity which results in a change in transport parameters of cholic acid and thymidine. The change in age-dependent lipid-protein interactions was demonstrated by spin-label measurements in model membranes. The results demonstrated that peroxidative break-down of lipids is an ongoing post-transcriptional process of ageing. The possible role of protective repair mechanisms is discussed.

  6. Biological properties of novel ruthenium- and osmium-nitrosyl complexes with azole heterocycles.

    PubMed

    Novak, Maria S; Büchel, Gabriel E; Keppler, Bernhard K; Jakupec, Michael A

    2016-06-01

    Since the discovery that nitric oxide (NO) is a physiologically relevant molecule, there has been great interest in the use of metal nitrosyl compounds as antitumor pharmaceuticals. Particularly interesting are those complexes which can deliver NO to biological targets. Ruthenium- and osmium-based compounds offer lower toxicity compared to other metals and show different mechanisms of action as well as different spectra of activity compared to platinum-based drugs. Novel ruthenium- and osmium-nitrosyl complexes with azole heterocycles were studied to elucidate their cytotoxicity and possible interactions with DNA. Apoptosis induction, changes of mitochondrial transmembrane potential and possible formation of reactive oxygen species were investigated as indicators of NO-mediated damage by flow cytometry. Results suggest that ruthenium- and osmium-nitrosyl complexes with the general formula (indazolium)[cis/trans-MCl4(NO)(1H-indazole)] have pronounced cytotoxic potency in cancer cell lines. Especially the more potent ruthenium complexes strongly induce apoptosis associated with depolarization of mitochondrial membranes, and elevated reactive oxygen species levels. Furthermore, a slight yet not unequivocal trend to accumulation of intracellular cyclic guanosine monophosphate attributable to NO-mediated effects was observed.

  7. Preparation and biological properties of a melibiose binding lectin from Bauhinia variegata seeds.

    PubMed

    Lin, Peng; Ng, Tzi Bun

    2008-11-26

    A dimeric 64-kDa melibiose-binding lectin was isolated from the seeds of Bauhinia variegata. The isolation procedure comprised affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Mono Q, and gel filtration on Superdex 75. The lectin was adsorbed on the first two chromatographic media. Its hemagglutinating activity was stable after 30-min exposure to temperatures up to 70 degrees C. Since lectins may demonstrate biological activities such as antiproliferative, immunomodulatory, antifungal, antiviral, and HIV-1 reverse transcriptase inhibitory activities, the isolated lectin was tested for these activities. It was found that the lectin inhibited proliferation in hepatoma HepG2 cells and breast cancer MCF7 cells with an IC(50) of 1.4 microM and 0.18 microM, respectively. HIV-1 reverse transcriptase activity was inhibited with an IC(50) of 1.02 microM. The lectin and concanavalin A (Con A) evoked maximal mitogenic response from mouse splenocytes at similar concentrations, but the maximal response to B. variegata lectin was only 1/5 of that induced by Con A in magnitude. B. variegata lectin was devoid of antifungal activity.

  8. Biological and biochemical properties of two Xenopus laevis N-acetylgalactosaminyltransferases with contrasting roles in embryogenesis.

    PubMed

    Voglmeir, Josef; Laurent, Nicolas; Flitsch, Sabine L; Oelgeschläger, Michael; Wilson, Iain B H

    2015-02-01

    The biosynthesis of mucin-type O-linked glycans in animals is initiated by members of the large family of polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts), which play important roles in embryogenesis, organogenesis, adult tissue homeostasis and carcinogenesis. Until now, the mammalian forms of these enzymes have been the best characterized. However, two N-acetylgalactosaminyltransferases (xGalNAc-T6 and xGalNAc-T16) from the African clawed frog (Xenopus laevis), which are most homologous to those encoded by the human GALNT6 and GALNT16 (GALNTL1) genes, were shown to have contrasting roles in TGF-β/BMP signaling in embryogenesis. In this study we have examined these two enzymes further and show differences in their in vivo function during X. laevis embyrogenesis as evidenced by in situ hybridization and overexpression experiments. In terms of enzymatic activity, both enzymes were found to be active towards the EA2 peptide, but display differential activity towards a peptide based on the sequence of ActR-IIB, a receptor relevant to TGF-β/BMP signaling. In summary, these data demonstrate that these two enzymes from different branches of the N-acetylgalactosaminyltransferase do not only display differential substrate specificities, but also specific and distinct expression pattern and biological activities in vivo.

  9. Therapeutic Uses and Pharmacological Properties of Garlic, Shallot, and Their Biologically Active Compounds

    PubMed Central

    Mikaili, Peyman; Maadirad, Surush; Moloudizargari, Milad; Aghajanshakeri, Shahin; Sarahroodi, Shadi

    2013-01-01

    Objective(s): Garlic (Allium sativum L. family Liliaceae) is well known in Iran and its leaves, flowers, and cloves have been used in traditional medicine for a long time. Research in recent decades has shown widespread pharmacological effects of A. sativum and its organosulfur compounds especially Allicin. Studies carried out on the chemical composition of the plant show that the most important constituents of this plant are organosulfur compounds such as allicin, diallyl disulphide, S-allylcysteine, and diallyl trisulfide. Allicin represents one of the most studied among these naturally occurring compounds. In addition to A. sativum, these compounds are also present in A. hirtifolium (shallot) and have been used to treat various diseases. This article reviews the pharmacological effects and traditional uses of A. sativum, A. hirtifolium, and their active constituents to show whether or not they can be further used as potential natural sources for the development of novel drugs. Materials and Methods: For this purpose, the authors went through a vast number of sources and articles and all needed data was gathered. The findings were reviewed and classified on the basis of relevance to the topic and a summary of all effects were reported as tables. Conclusion: Garlic and shallots are safe and rich sources of biologically active compounds with low toxicity. Further studies are needed to confirm the safety and quality of the plants to be used by clinicians as therapeutic agents. PMID:24379960

  10. Therapeutic uses and pharmacological properties of garlic, shallot, and their biologically active compounds.

    PubMed

    Mikaili, Peyman; Maadirad, Surush; Moloudizargari, Milad; Aghajanshakeri, Shahin; Sarahroodi, Shadi

    2013-10-01

    Garlic (Allium sativum L. family Liliaceae) is well known in Iran and its leaves, flowers, and cloves have been used in traditional medicine for a long time. Research in recent decades has shown widespread pharmacological effects of A. sativum and its organosulfur compounds especially Allicin. Studies carried out on the chemical composition of the plant show that the most important constituents of this plant are organosulfur compounds such as allicin, diallyl disulphide, S-allylcysteine, and diallyl trisulfide. Allicin represents one of the most studied among these naturally occurring compounds. In addition to A. sativum, these compounds are also present in A. hirtifolium (shallot) and have been used to treat various diseases. This article reviews the pharmacological effects and traditional uses of A. sativum, A. hirtifolium, and their active constituents to show whether or not they can be further used as potential natural sources for the development of novel drugs. For this purpose, the authors went through a vast number of sources and articles and all needed data was gathered. The findings were reviewed and classified on the basis of relevance to the topic and a summary of all effects were reported as tables. Garlic and shallots are safe and rich sources of biologically active compounds with low toxicity. Further studies are needed to confirm the safety and quality of the plants to be used by clinicians as therapeutic agents.

  11. Composting of the solid fraction of digestate derived from pig slurry: Biological processes and compost properties.

    PubMed

    Tambone, Fulvia; Terruzzi, Laura; Scaglia, Barbara; Adani, Fabrizio

    2015-01-01

    The aim of this paper was to assess the characteristics of the solid fractions (SF) obtained by mechanical separation of digestate, their compostability and compost quality. To do so, the SF of digestates obtained from anaerobic digestion of pig slurry, energy crops and agro-industrial residues were sampled in five plants located in Northern Italy. Results obtained indicated that anaerobic digestion by itself promoted the high biological stability of biomasses with a Potential Dynamic Respiration Index (PDRI) close to 1000 mgO2 kg V S(-1)h(-1). Subsequent composting of digestates, with an added bulking agent, did not give remarkably different results, and led only to a slight modification of the characteristics of the initial non-composted mixtures; the composts obtained fully respected the legal limits for high quality compost. Chemical studies of organic matter composition of the biomasses by using CP MAS (13)C NMR, indicated that the compost was composed of a high relative content of O-alkyl-C (71.47% of total C) (cellulose and hemicelluloses) and a low alkyl-C (12.42%) (i.e. volatile fatty acids, steroid-like molecules, aliphatic biopolymers and proteins).

  12. New insights into the biological activity and secretion properties of a polypeptide derived from tilapia somatotropin.

    PubMed

    Acosta, Jannel; Carpio, Yamila; Morales, Reynold; Aguila, Julio César; Acanda, Yosvani; Herrera, Fidel; Estrada, Mario P

    2010-08-01

    In a previous study, we unexpectedly found that tilapia growth hormone (tiGH) secreted to the culture media by transformed cells of the yeast Pichia pastoris lacks 46 amino acids from the C-terminal end. In the present study, we cloned the exact fragment that code for this truncated variant and demonstrated its growth promoting activity in goldfish when it's administered by immersion bath. Furthermore, a better characterization of this polypeptide was performed. Administration of the polypeptide derived from tiGH increased superoxide anion production and has a mitogenic effect on peripheral blood leukocytes. This molecule binds to liver membranes proteins in vitro in a saturable manner. Beside, we cloned and expressed tiGH and its truncated variant in mammalian cells using the signal peptide of this hormone and we observed that the secretion was drastically reduced in the truncated tiGH as compared to the intact molecule. Truncated tilapia growth hormone lacking the helix 4 and two disulfide loops is still a bioactive hormone, suggesting that the disulfide bonds and the helix 4 are not essential for the biological activities examined in this work. However, the growth hormone C-terminal portion seems to be essential for this hormone to be secreted by cultured cells in vitro. 2010 Elsevier Inc. All rights reserved.

  13. A survey of schistosome protein domain types: insights into unique biological properties

    PubMed Central

    Hughes, Austin L.; Friedman, Robert

    2012-01-01

    Using the PROSITE database and search tools, we conducted a comprehensive bioinformatic analysis of the predicted protein sequences of the flatworm parasites Schistosoma mansoni and S. japonicum and seven other animal genomes in order to identify novel schistosome-specific features. Our analyses revealed a relative paucity of proline-rich domains in schistosomes in comparison with their human host and a corresponding enrichment in schistosomes of asparagine-rich, serine-rich, and threonine-rich domains. Domain types found in both schistosome species but not in human included the two-component system sensor histidine kinase/response regulator; C83 family peptidase; DyP-type peroxidase; and densovirus NS1-type domain. Unique features of the schistosome proteome may help guide development of new drugs, while the presence of a densovirus-derived protein in S. mansoni suggests that this species may be infected by a virus of this group, which might be useful as a biological control agent. PMID:21315771

  14. Influence of taro (Colocasia esculenta L. Shott) growth conditions on the phenolic composition and biological properties.

    PubMed

    Gonçalves, Rui F; Silva, Artur M S; Silva, Ana Margarida; Valentão, Patrícia; Ferreres, Federico; Gil-Izquierdo, Angel; Silva, João B; Santos, Delfim; Andrade, Paula B

    2013-12-15

    Colocasia esculenta (L.) Shott, commonly known as taro, is an essential food for millions of people. The leaves are consumed in sauces, purees, stews, and soups, being also used in wound healing treatment. Nowadays, the consumers' demand for bioactive compounds from the diet led to the development of new agricultural strategies for the production of health-promoting constituents in vegetables. In this work, two strategies (variety choice and irrigation conditions) were considered in the cultivation of C. esculenta. The effect on the phenolic composition of the leaves was evaluated. Furthermore, a correlation between the biological activity of the different varieties and their chemical composition was established. Qualitative and quantitative differences in the phenolic composition were observed between varieties; furthermore, the irrigation conditions also influenced the composition. C. esculenta varieties were able to scavenge several oxidant species and to inhibit hyaluronidase, but data suggest that metabolites other than phenolics are involved. The results show that cultivation strategies can effectively modulate the accumulation of these types of bioactive compounds. Furthermore C. esculenta wound healing potential can be attributed, at least in part, to the protection of the wound site against oxidative/nitrosative damage and prevention of hyaluronic acid degradation.

  15. [Biologically active peptides derived from food proteins as the food components with cardioprotective properties].

    PubMed

    Iwaniak, Anna; Darewicz, Małgorzata; Minkiewicz, Piotr; Protasiewicz, Monika; Borawska, Justyna

    2014-06-01

    Food proteins are the source of peptides with many biological activities. One of them is their impact on bl