Immobilization of Acetobacter aceti by adhesion

1988 ◽  
Vol 34 (5) ◽  
pp. 638-644 ◽  
Author(s):  
M. P. Hermesse ◽  
C. Dereppe ◽  
Y. Bartholome ◽  
P. G. Rouxhet
Keyword(s):  
Electrostatic Interactions ◽  
Ferric Ions ◽  
Binding Agent ◽  
Acetobacter Aceti ◽  
Lower Cell Density ◽  
A Cell ◽  
Previously Treated ◽  
Electrostatic Repulsions ◽  
Hydrophobic Bonding ◽  
Reduced Surface

The attachment of three strains of Acetobacter aceti (ATCC 23747, ATCC 23748, NCIB 8246), with or without capsule, cultured under different conditions has been investigated in solutions of controlled pH. Various materials (silicates, organic polymers) have been used as supports, and the results have been related to the surface properties of the cells and supports. Cells that do not have a capsule do not adhere to the tested materials, whatever their hydrophobicity, unless the latter are previously treated by ferric ions to make their surface less negative. Cells that possess a capsule adhere to non-treated supports. In all cases the highest density of the adhering cellular film is obtained when the electrostatic repulsions between a cell and the support and between cells are reduced (surface charge of the support less negative, lower pH). The capsule influences adhesion by affecting the interplay between electrostatic interactions and hydrophobic bonding; moreover, capsule polymers may favor adhesion by acting as binding agent. The occurrence of cell flocculation gives rise to greater heterogeneity and lower cell density in the film of adhering cells.

scholarly journals Bone Regeneration in Defects Compromised by Radiotherapy

2009 ◽  
Vol 89 (1) ◽  
pp. 77-81 ◽  
Author(s):  
W.-W. Hu ◽  
B.B. Ward ◽  
Z. Wang ◽  
P.H. Krebsbach
Keyword(s):  
Bone Regeneration ◽  
Bone Development ◽  
Micro Ct ◽  
Mineral Density ◽  
Woven Bone ◽  
Before And After ◽  
Biomaterial Scaffolds ◽  
A Cell ◽  
Previously Treated ◽  
Freely Suspended

Because bone reconstruction in irradiated sites is less than ideal, we applied a regenerative gene therapy method in which a cell-signaling virus was localized to biomaterial scaffolds to regenerate wounds compromised by radiation therapy. Critical-sized defects were created in rat calvariae previously treated with radiation. Gelatin scaffolds containing lyophilized adenovirus encoding BMP-2 (AdBMP-2) or freely suspended AdBMP-2 were transplanted. Lyophilized AdBMP-2 significantly improved bone quality and quantity over free AdBMP-2. Bone mineral density was reduced after radiotherapy. Histological analyses demonstrated that radiation damage led to less bone regeneration. The woven bone and immature marrow formed in the radiated defects indicated that irradiation retarded normal bone development. Finally, we stored the scaffolds with lyophilized AdBMP-2 at −80°C to determine adenovirus stability. Micro-CT quantification demonstrated no significant differences between bone regeneration treated with lyophilized AdBMP-2 before and after storage, suggesting that virus-loaded scaffolds may be convenient for application as pre-made constructs.

The in vivo efficacy of docetaxel and cabazitaxel in a cell-line based xenograft of castration-resistant prostate cancer (CRPC) previously treated with enzalutamide.

2014 ◽  
Vol 32 (15_suppl) ◽  
pp. 5046-5046 ◽  
Author(s):  
Robert J. van Soest ◽  
Ellen S. de Morrée ◽  
Corrina M.A. de Ridder ◽  
Herman Burger ◽  
Erik A.C. Wiemer ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Line ◽  
Castration Resistant Prostate Cancer ◽  
In Vivo Efficacy ◽  
Castration Resistant ◽  
A Cell ◽  
Previously Treated

scholarly journals The Effect of Lycopene Preexposure on UV-B-Irradiated Human Keratinocytes

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Andreia Ascenso ◽  
Tiago Pedrosa ◽  
Sónia Pinho ◽  
Francisco Pinho ◽  
José Miguel P. Ferreira de Oliveira ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Annexin V ◽  
Human Keratinocytes ◽  
Protective Role ◽  
Cell Cycle Distribution ◽  
Skin Cells ◽  
A Cell ◽  
Previously Treated ◽  
Annexin V Assay ◽  
And Oxidative Stress

Lycopene has been reported as the antioxidant most quickly depleted in skin upon UV irradiation, and thus it might play a protective role. Our goal was to investigate the effects of preexposure to lycopene on UV-B-irradiated skin cells. Cells were exposed for 24 h to 10 M lycopene, and subsequently irradiated and left to recover for another 24 h period. Thereafter, several parameters were analyzed by FCM and RT-PCR: genotoxicity/clastogenicity by assessing the cell cycle distribution; apoptosis by performing the Annexin-V assay and analyzing gene expression of apoptosis biomarkers; and oxidative stress by ROS quantification. Lycopene did not significantly affect the profile of apoptotic, necrotic and viable cells in nonirradiated cells neither showed cytostatic effects. However, irradiated cells previously treated with lycopene showed an increase in both dead and viable subpopulations compared to nonexposed irradiated cells. In irradiated cells, lycopene preexposure resulted in overexpression ofBAXgene compared to nonexposed irradiated cells. This was accompanied by a cell cycle delay at S-phase transition and consequent decrease of cells in G0/G1 phase. Thus, lycopene seems to play a corrective role in irradiated cells depending on the level of photodamage. Thus, our findings may have implications for the management of skin cancer.

scholarly journals Encapsulation of Synthesized Plant Growth Regulator Based on Copper(II) Complex in Chitosan/Alginate Microcapsules

2021 ◽  
Vol 22 (5) ◽  
pp. 2663
Author(s):  
Darikha Kudasova ◽  
Botagoz Mutaliyeva ◽  
Kristina Vlahoviček-Kahlina ◽  
Slaven Jurić ◽  
Marijan Marijan ◽  
...  
Keyword(s):  
Plant Growth ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Electrostatic Interactions ◽  
Growth Regulation ◽  
Profile Analysis ◽  
Fickian Diffusion ◽  
Controlling Mechanism ◽  
High Concentrations ◽  
Reduced Surface

A new copper complex, trans-diaqua-trans-bis [1-hydroxy-1,2-di (methoxycarbonyl) ethenato] copper (abbreviation Cu(II) complex), was synthesized and its plant growth regulation properties were investigated. The results show a sharp dependence of growth regulation activity of the Cu(II) complex on the type of culture and its concentration. New plant growth regulator accelerated the development of the corn root system (the increase in both length and weight) but showed a smaller effect on the development of the wheat and barley root systems. Stimulation of corn growth decreased with increasing Cu(II) complex concentration from 0.0001% to 0.01% (inhibition at high concentrations—0.01%). The development of corn stems was also accelerated but to a lesser extent. Chitosan-coated calcium alginate microcapsules suitable for delivery of Cu(II) complex to plants were prepared and characterized. Analysis of the FTIR spectrum showed that complex molecular interactions between functional groups of microcapsule constituents include mainly electrostatic interactions and hydrogen bonds. Microcapsules surface exhibits a soft granular surface structure with substructures consisting of abundant smaller particles with reduced surface roughness. Release profile analysis showed Fickian diffusion is the rate-controlling mechanism of Cu(II) complex releasing. The obtained results give new insights into the complexity of the interaction between the Cu(II) complex and microcapsule formulation constituents, which can be of great help in accelerating product development for the application in agriculture

scholarly journals Application of Cationic Conjugated Polymer–Outer Membrane Vesicle Complexes in Inhibiting Red Blood Cell Aggregation

2019 ◽  
Vol 01 (01) ◽  
pp. 038-042
Author(s):  
Ping He ◽  
Endong Zhang ◽  
Ruilian Qi ◽  
Fengting Lv ◽  
Libing Liu ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Cell Aggregation ◽  
Outer Membrane Vesicles ◽  
Photoelectric Properties ◽  
Rbc Aggregation ◽  
A Cell

Cationic conjugated polymers (CCPs) have been attracting a lot of attention in biomedical applications because of their good photoelectric properties and good cell viability. However, positively charged components may reduce the electrostatic repulsion among red blood cells (RBCs) and induce RBC aggregation, which may lead to thrombus. Herein, in this work, we prepared the complexes of CCPs and outer membrane vesicles (OMVs) to inhibit RBC aggregation induced by CCPs and improve the biocompatibility of CCPs. A poly(fluorene-co-phenylene) derivative (PFP), a poly(p-phenylenevinylene) derivative (PPV), and a poly(thiophene) derivative (PMNT) were chosen as the model CCPs, and OMVs were used as the representative of a cell membrane. The CCP–OMV complexes were formed mainly driven by electrostatic interactions. Besides, the electrostatic CCP–OMV complexes were proved to be able to prevent the RBC aggregation induced by CCPs while maintaining the hydrophobic interactions between CCPs and RBCs.

Electrostatic interactions between particles through heterogeneous fluid phases

Soft Matter ◽  
2017 ◽  
Vol 13 (37) ◽  
pp. 6647-6658 ◽  
Author(s):  
Dong Woo Kang ◽  
Mina Lee ◽  
Kyung Hak Kim ◽  
Ming Xia ◽  
Sang Hyuk Im ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Polymer Particles ◽  
Fluid Media ◽  
Electrostatic Repulsions ◽  
Fluid Phases

Gravitational confinement of polymer particles due to electrostatic repulsions between the particles through heterogeneous fluid media.

A THEORETICAL COMPARISON OF CONFORMATIONAL FEATURES OF CALIX[4]AROMATICS

2004 ◽  
Vol 03 (01) ◽  
pp. 51-68 ◽  
Author(s):  
DI-FEI WANG ◽  
YUN-DONG WU
Keyword(s):  
Hydrogen Bonds ◽  
Electrostatic Interactions ◽  
Conformational Preference ◽  
Cone Conformation ◽  
Structural Modifications ◽  
Hydrogen Bonding Interactions ◽  
Partial Cone ◽  
Conformational Preferences ◽  
Intramolecular Hydrogen ◽  
Electrostatic Repulsions

Although there are tremendous studies about the conformational feature of calix[4]arenes and its analogies, no theoretical study has been done systematically about why some structural modifications could completely lead to a change of conformational preference. For example, calix[4]arene 1 adopts a cone conformation while its analogue calix[4]pyrrole 7 only adopts a 1,3-alternate conformation. So if this is only because of the effect of OH—OH hydrogen bonds, then why does O-methyl substituted calix[4]arene 2 still has cone conformation? In this paper, the conformational features of a series of seven calix[4]aromatics, calix[4]arene and calix[4]pyrrole related structures, have been investigated at BLYP/6–31G* level both in the gas phase and in CH 2 Cl 2 solution. The calculations demonstrated that three main factors influence the conformational preference of these calix[4]aromatics, i.e. the intramolecular hydrogen bond, the adjacent ring-ring electrostatic interaction and the intrinsic flexibility of the [14] metacyclophane framework. Calix[4]benzene 3 and calix[4]pyridine 4 have little conformational preferences due to their flexible [14] metacyclophane framework, the lack of hydrogen-bonding interactions and weak ring-ring electrostatic interactions. In contrast, calix[4]aromatics 1 and 5–7 have either intramolecular hydrogen bonds (1) or ring-ring electrostatic interactions (5–7). Consequently, calix[4]arene 1 has the cone preference and calix[4]pyrrole, calix[4]furan, and calixthiophene (5–7) have the 1,3-alternate preference. Methoxy calix[4]arene prefers a cone or partial cone conformation, because the 1,3-alternate and 1,2-alternate conformations are destabilized by electrostatic repulsions involving the methoxy group and the adjacent phenyl ring.

scholarly journals Metschnikowia Strains Isolated from Botrytized Grapes Antagonize Fungal and Bacterial Growth by Iron Depletion

2006 ◽  
Vol 72 (10) ◽  
pp. 6716-6724 ◽  
Author(s):  
Matthias Sipiczki
Keyword(s):  
Iron Acquisition ◽  
Antagonistic Activity ◽  
Microbial Populations ◽  
Iron Binding ◽  
Ferric Ions ◽  
Binding Agent ◽  
Pigment Formation ◽  
Inhibition Zones ◽  
High Concentrations ◽  
Pigment Accumulation

ABSTRACT Noble-rotted grapes are colonized by complex microbial populations. I isolated pigment-producing Metschnikowia strains from noble-rotted grapes that had antagonistic activity against filamentous fungi, yeasts, and bacteria. A red-maroon pigment was formed from a diffusible colorless precursor released by the cells into the medium. The conversion of the precursor required iron and could occur both in the cells (red colonies) and in the medium (red halos around colonies). The intensity of pigmentation was correlated with the intensity of the antimicrobial activity. Mutants that did not form pigment also lacked antifungal activity. Within the pigmented halos, conidia of the sensitive fungi did not germinate, and their hyphae did not grow and frequently lysed at the tips. Supplementation of the medium with iron reduced the size of the halos and the inhibition zones, while it increased the pigment accumulation by the colonies. The iron-binding agent tropolone had a similar effect, so I hypothesize that pigmented Metschnikowia isolates inhibit the growth of the sensitive microorganisms by pigment formation, which depletes the free iron in the medium. As the pigment is a large nondiffusible complex produced in the presence of both low and high concentrations of ferric ions, the proposed mechanism is different from the mechanisms operating in microbes that release siderophores into the environment for iron acquisition.

Nanocarriers as Non-Viral Vectors in Gene Delivery Application

2018 ◽  
pp. 357-380
Author(s):  
Upendra Bulbake ◽  
Anjali Jain ◽  
Wahid Khan
Keyword(s):  
Gene Delivery ◽  
Electrostatic Interactions ◽  
Viral Vectors ◽  
Cationic Polymer ◽  
Biomedical Science ◽  
Intracellular Release ◽  
Life Threatening ◽  
A Cell ◽  
Low Toxicity ◽  
Extracellular Environment

Gene therapy is the emerging trend in biomedical science for treatment of life-threatening diseases. This involves delivery of a therapeutic gene to the nucleus of an affected cell by a suitable vector. Gene delivery using non-viral vectors such as cationic polymer and lipid is gaining attention due to their favourable properties, including lack of immunogenicity, low toxicity, and potential for tissue specificity when compared with viral vectors. A variety of non-viral vectors have been proposed, most of which facilitate gene delivery by electrostatic interactions, encapsulation, and in some cases, condensing nucleic acids into nano-sized particles which can then be taken up by cells. Successful gene delivery within a cell is the nanocarrier's ability to protect its contents from degradation in the extracellular environment. A well-designed nanocarrier will promote cellular uptake and intracellular release of the nucleic acid. This chapter highlights different polymers, lipids, and their nanocarriers employed for gene delivery along with clinical trials.

scholarly journals A S-cysteine conjugate, precursor of aroma of White Sauvignon

OENO One ◽  
1995 ◽  
Vol 29 (4) ◽  
pp. 227 ◽  
Author(s):  
Takatoshi Tominaga ◽  
Isabelle Masneuf-Pomarède ◽  
Denis Dubourdieu
Keyword(s):  
Pyridoxal Phosphate ◽  
The Other ◽  
Cell Free Extract ◽  
Crude Preparation ◽  
Lyase Activity ◽  
A Cell ◽  
Previously Treated ◽  
Eubacterium Limosum ◽  
Enzyme Source

<p style="text-align: justify;">4-mercapto-4-methylpentan-2-one (4-MMP), a strongly odorant compound responsible for the « boxtree » or « broom plant » odour of the Sauvignon wines, can be enzymaticaly released <em>in vitro</em> from an odourless must extract. The enzyme source used is a cell-free extract of the gastrointestinal bacterium <em>Eubacterium limosum</em>. This crude preparation exhibits a cysteine β-lyase activity which requires the presence of pyridoxal phosphate. The release of 4-MMP is inhibited when the substrate is previously treated with N-hydroxysuccimide acetate which reacts with a primary amine. The same bacterial extract is also able to release 4-MMP, pyruvic acid and ammonium, from S-(4-méthylpentan-2-one)-L-cysteine. On the other hand, the cleavage of S-(4-méthylpentan-2-one)D,L-homocysteine and S-(4-méthylpentan-2-one)- glutathione is very limited. These results suggest that the precursor of 4-MMP in Sauvignon must is a S-cysteine conjugate. Such an aroma precursor in grapes or in other fruits has never been round berore.</p>

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