scholarly journals The membrane depolarization and increase intracellular calcium level produced by silver nanoclusters are responsible for bacterial death

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Junior Bernardo Molina-Hernandez ◽  
Antonio Aceto ◽  
Tonino Bucciarelli ◽  
Domenico Paludi ◽  
Luca Valbonetti ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Membrane Depolarization ◽  
Silver Nanoclusters ◽  
Common Mechanism ◽  
Bacterial Survival ◽  
Intracellular Level ◽  
Fluorescence Techniques ◽  
Intracellular Calcium Level ◽  
Chemical Constitution ◽  
First Time

AbstractThis work highlights how our silver ultra nanoclusters (ARGIRIUM-SUNc) hand-made synthesized, are very useful as a bactericide and anti-biofilm agent. The Argirium-SUNc effective antibacterial concentrations are very low (< 1 ppm) as compared to the corresponding values reported in the literature. Different bacterial defense mechanisms are observed dependent on ARGIRIUM-SUNc concentrations. Biochemical investigations (volatilome) have been performed to understand the pathways involved in cell death. By using fluorescence techniques and cell viability measurements we show, for the first time, that membrane depolarization and calcium intracellular level are both primary events in bacteria death. The ARGIRIUM-SUNc determined eradication of different biofilm at a concentration as low as 0.6 ppm. This suggests that the effect of the nanoparticles follows a common mechanism in different bacteria. It is highly probable that the chemical constitution of the crosslinks could be a key target in the disrupting mechanism of our nanoparticles. Since the biofilms and their constituents are essential for bacterial survival in contact with humans, the silver nanoparticles represent a logical target for new antibacterial treatments.

CHARACTERISTICS OF AGE-DEPENDENT CHANGES IN THE URINE'S PROTEOM COMPOSITION OF THE HEALTHY PERSONS (EXPERIMENTAL AND THEORETICAL STUDY)

2020 ◽  
pp. 735-740
Author(s):  
Л. Х. Пастушкова ◽  
Д. Н. Каширина ◽  
А. Г. Гончарова ◽  
Н. Б. Захарова ◽  
Е. С. Тийс ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Insulin Signaling ◽  
Defense Mechanisms ◽  
Theoretical Study ◽  
Clinical Manifestations ◽  
Age Dependent ◽  
First Time ◽  
Healthy Persons ◽  
Over Time

Впервые описаны белки, достоверно увеличивающиеся и уменьшающиеся в моче с возрастом в интервале 20-60 лет. Охарактеризованы комбинации белков, связанных с изменением иммунных процессов, нарушением реологии крови, в том числе риском коагулопатии, противоопухолевых защитных механизмов, инсулинового сигнального пути, с изменением характеристик клеточного деления и качества новообразованной ткани. Таким образом, возрастная динамика основных процессов запускает каскад реакций, проявляющихся в замыкании «патологических биохимических кругов», которые формируют предпосылки к развитию заболеваний и, с течением времени, клинические проявления. For the first time proteins are described, reliably increasing and decreasing in urine with age in the range of 20 to 60 years. The combinations of proteins associated with changes in immune processes, violation of blood reology, including the risk of coagulopathy, anticancer defense mechanisms, insulin signaling pathway, changes in cell characteristics are characterized division and quality of the newly formed fabric. Thus, the age dynamics of the main processes triggers a cascade of reactions manifested in the closure of «pathological biochemical circles» that form the prerequisites for the development of diseases and, over time, clinical manifestations.

scholarly journals Macrophage Autophagy and Oxidative Stress: An Ultrastructural and Immunoelectron Microscopical Study

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Ida Perrotta ◽  
Valentina Carito ◽  
Emilio Russo ◽  
Sandro Tripepi ◽  
Saveria Aquila ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Defense Mechanisms ◽  
Ultrastructural Localization ◽  
Microscopical Study ◽  
Beclin 1 ◽  
Cell Organelles ◽  
A Cell ◽  
First Time

The word autophagy broadly refers to the cellular catabolic processes that lead to the removal of damaged cytosolic proteins or cell organelles through lysosomes. Although autophagy is often observed during programmed cell death, it may also serve as a cell survival mechanism. Accumulation of reactive oxygen species within tissues and cells induces various defense mechanisms or programmed cell death. It has been shown that, besides inducing apoptosis, oxidative stress can also induce autophagy. To date, however, the regulation of autophagy in response to oxidative stress remains largely elusive and poorly understood. Therefore, the present study was designed to examine the ratio between oxidative stress and autophagy in macrophages after oxidant exposure (AAPH) and to investigate the ultrastructural localization of beclin-1, a protein essential for autophagy, under basal and stressful conditions. Our data provide evidence that oxidative stress induces autophagy in macrophages. We demonstrate, for the first time by immunoelectron microscopy, the subcellular localization of beclin-1 in autophagic cells.

scholarly journals Constituents of Da-Cheng-Qi Decoction and its Parent Herbal Medicines Determined by LC-MS/MS

2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500
Author(s):  
Fengguo Xu ◽  
Ying Liu ◽  
Rui Song ◽  
Haijuan Dong ◽  
Zunjian Zhang
Keyword(s):  
High Performance ◽  
Herbal Medicines ◽  
Gradient Elution ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Esi Ms ◽  
Chemical Constitution ◽  
Tandem Mass Spectrometric ◽  
Liquid Chromatographic ◽  
First Time

Da-Cheng-Qi decoction (DCQD) is a purgative prescription used in China and East Asia. To profile the constituents of this complex traditional Chinese medicine (TCM), a high-performance liquid chromatographic, electrospray ionization, tandem mass spectrometric (HPLC-ESI/MS/MS) analytical method was developed. After separation on a reversed-phase C18 analytical column using gradient elution, samples were analyzed by ESI-MS/MS in negative mode. As a result, a total of 37 compounds were detected, of which two tannins, three anthraquinones, two sennosides, five flavonoids and two lignans were unambiguously identified by comparison with standard compounds, and sixteen compounds were either tentatively identified or deduced according to their MS/MS data. The fragmentation pathways of many of the observed compounds, such as the tannins and lignans are reported for the first time. In addition, the identity of each peak in DCQD was explored by comparison with those of its three constituent herbs. The results indicated that tannins, anthraquinones and sennosides in DCQD originated from Radix et Rhizoma Rhei, flavonoids from Fructus Aurantii Immaturus, and lignans from Cortex Magnoliae officinalis. The present study provides an example of chemical constitution profiling in complex TCM systems using LC/MS/MS.

scholarly journals Recombination of Feline calicivirus within an endemically infected cat colony

2006 ◽  
Vol 87 (4) ◽  
pp. 921-926 ◽  
Author(s):  
K. P. Coyne ◽  
F. C. Reed ◽  
C. J. Porter ◽  
S. Dawson ◽  
R. M. Gaskell ◽  
...  
Keyword(s):  
Recombinant Virus ◽  
Recombination Event ◽  
Common Mechanism ◽  
Feline Calicivirus ◽  
First Report ◽  
The Family ◽  
Distinct Strain ◽  
First Time

To understand the evolution of the family Caliciviridae, the persistence of Feline calicivirus (FCV) was studied within an endemically infected cat colony. Polymerase and capsid sequences were analysed for 34 FCV isolates obtained over a 4 year period. Initially, the colony was infected with one strain of virus, but a second distinct strain was later identified. Subsequently, the emergence of a recombinant virus was observed, containing elements of both of the strains circulating within the colony. The recombination event mapped close to the ORF1/ORF2 junction. This is consistent with recombination in other caliciviruses, suggesting a common mechanism within this family. This is the first report of recombination within the genus Vesivirus in the family Caliciviridae and the first time that a recombination event has been observed where the parental strains have also been identified.

Circularly polarized luminescence in chiral silver nanoclusters

2017 ◽  
Vol 53 (7) ◽  
pp. 1269-1272 ◽  
Author(s):  
Jatish Kumar ◽  
Tsuyoshi Kawai ◽  
Takuya Nakashima
Keyword(s):  
Circular Dichroism ◽  
Mirror Image ◽  
Silver Nanoclusters ◽  
Dihydrolipoic Acid ◽  
Circularly Polarized ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence ◽  
First Time ◽  
Circular Dichroïsm

Sets of mirror image circular dichroism (CD) and circularly polarized luminescence (CPL) spectra are for the first time demonstrated using enantiomeric dihydrolipoic acid (DHLA)-capped silver nanoclusters.

Mechanisms and models for homogeneous copper mediated ligand exchange reactions of the type: CuNu + ArX → ArNu + CuX

1985 ◽  
Vol 63 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Christiane Couture ◽  
Anthony James Paine
Keyword(s):  
Molecular Design ◽  
Nucleophilic Aromatic Substitution ◽  
Common Mechanism ◽  
Aromatic Substitution ◽  
Exchange Reactions ◽  
Design And Synthesis ◽  
Alkyl Groups ◽  
Leaving Group ◽  
First Time ◽  
Redox Equilibria

The title reactions are an important class of copper mediated nucleophilic aromatic substitution processes, which constitute a useful tool in the molecular design and synthesis of small molecules. We report the results of extensive investigation of these processes, primarily focussing on cyanodeiodination (ArI + CuCN → CuI + ArCN). Among the interesting features of these processes are: (a) an unusual rate equation involving autocatalysis by CuI product; (b) retardation by both excess nucleophile (as KCN) and excess leaving group (as KI), which compete with ArX to complex with CuNu; (c) only cuprous nucleophiles are active (ligand exchanged products from cupric salts arise from prior redox equilibria which form CuNu); (d) the halogen effect is large (kI ~ 40–100 kBr ~ 300–5000kCl) but the Hammett ρ value is zero; (e) ortho-alkyl groups do not hinder the reaction (and actually cause mild acceleration by relief of steric strain). Finally, the introduction of an ortho-COO− group accelerates the reaction by a factor of 104–105, but the general features of the accelerated reactions are also the same, again indicating a common mechanism, with entropic acceleration by ortho-carboxylate. Both kinetic and thermodynamic factors were considered in detail, the latter apparently for the first time. Applications to practical syntheses are considered, and novel mechanistic models for these interesting processes are discussed.

scholarly journals Immunopathogenesis of Oropharyngeal Candidiasis in Human Immunodeficiency Virus Infection

2004 ◽  
Vol 17 (4) ◽  
pp. 729-759 ◽  
Author(s):  
Louis de Repentigny ◽  
Daniel Lewandowski ◽  
Paul Jolicoeur
Keyword(s):  
Human Immunodeficiency Virus ◽  
Transgenic Mice ◽  
Hiv Infection ◽  
Defense Mechanisms ◽  
Small Laboratory Animal ◽  
Effect Analysis ◽  
Immunodeficiency Virus ◽  
Cause And Effect Analysis ◽  
Mucosal Candidiasis ◽  
First Time

SUMMARY Oropharyngeal and esophageal candidiases remain significant causes of morbidity in human immunodeficiency virus (HIV)-infected patients, despite the dramatic ability of antiretroviral therapy to reconstitute immunity. Notable advances have been achieved in understanding, at the molecular level, the relationships between the progression of HIV infection, the acquisition, maintenance, and clonality of oral candidal populations, and the emergence of antifungal resistance. However, the critical immunological defects which are responsible for the onset and maintenance of mucosal candidiasis in patients with HIV infection have not been elucidated. The devastating impact of HIV infection on mucosal Langerhans' cell and CD4+ cell populations is most probably central to the pathogenesis of mucosal candidiasis in HIV-infected patients. However, these defects may be partly compensated by preserved host defense mechanisms (calprotectin, keratinocytes, CD8+ T cells, and phagocytes) which, individually or together, may limit Candida albicans proliferation to the superficial mucosa. The availability of CD4C/HIV transgenic mice expressing HIV-1 in immune cells has provided the opportunity to devise a novel model of mucosal candidiasis that closely mimics the clinical and pathological features of candidal infection in human HIV infection. These transgenic mice allow, for the first time, a precise cause-and-effect analysis of the immunopathogenesis of mucosal candidiasis in HIV infection under controlled conditions in a small laboratory animal.

scholarly journals Drosophila Histone Deacetylase 6 Protects Dopaminergic Neurons against α-Synuclein Toxicity by Promoting Inclusion Formation

2010 ◽  
Vol 21 (13) ◽  
pp. 2128-2137 ◽  
Author(s):  
Guiping Du ◽  
Xiang Liu ◽  
Xinping Chen ◽  
Mei Song ◽  
Yan Yan ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Histone Deacetylase ◽  
Dopaminergic Neurons ◽  
Critical Role ◽  
Ectopic Expression ◽  
Common Mechanism ◽  
Histone Deacetylase 6 ◽  
Inclusion Formation ◽  
Progressive Degeneration ◽  
First Time

Parkinson's disease (PD) is associated with progressive degeneration of dopaminergic (DA) neurons. We report for the first time that the Drosophila histone deacetylase 6 (dHDAC6) plays a critical role in the protection of DA neurons and the formation of α-synuclein inclusions by using a Drosophila PD model constructed by ectopic expression of human α-synuclein. Depletion of dHDAC6 significantly enhances the effects caused by ectopic expression of α-synuclein, namely, loss of DA neurons, retinal degeneration, and locomotor dysfunction. Expression of α-synuclein in the DA neurons leads to fewer inclusions in the brains of dHDAC6 mutant flies than in wild-type flies. Conversely, overexpression of dHDAC6 is able to suppress the α-synuclein–induced DA neuron loss and retinal degeneration and promote inclusion formation. Furthermore, mutation of dHDAC6 reinforces the accumulation of oligomers that are suggested to be a toxic form of α-synuclein. We propose that α-synuclein inclusion formation in the presence of dHDAC6 protects DA neurons from being damaged by oligomers, which may uncover a common mechanism for synucleinopathies.

The Importance of Amy Lynn

1994 ◽  
Vol 15 (3) ◽  
pp. 87-87 ◽  
Author(s):  
Vincent J. Menna
Keyword(s):  
Defense Mechanisms ◽  
Unusual Event ◽  
Practice Of Medicine ◽  
Seriously Ill Patients ◽  
First Time ◽  
Seriously Ill ◽  
Lay Public

Recently I became a grandfather for the first time, certainly not an unusual event. However, the gestation and birth of this little girl made me more keenly aware of my responsibilities and role as a physician and specifically as a pediatrician. Preoccupation with the practice of medicine and life in general may have clouded the memory of my own children as infants. In clinical residency, we often would distance ourselves emotionally from seriously ill patients by various defense mechanisms; it was difficult to experience children dying and their parents' grief. Too often, we would use terms or expressions that would be abhorrent to the lay public.

Electroionization study of ethylene: ionization and appearance energies, ion-pair formations, and negative ions

1987 ◽  
Vol 65 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Electron Impact ◽  
Negative Ions ◽  
High Sensitivity ◽  
Ion Pair ◽  
Common Mechanism ◽  
Threshold Region ◽  
Monoenergetic Electron ◽  
Text Fragment ◽  
First Time ◽  
Very High

Monoenergetic electron-impact threshold ionization and appearance curves of very high sensitivity of ethylene and all fragments containing at least one carbon atom are analyzed in detail. Ionization or appearance energies are measured for all ions, including the [Formula: see text] fragment. Structures are observed in the immediate [Formula: see text] threshold region, which are attributed to hot bands and to Rydberg autoionizing states. [Formula: see text],[Formula: see text] and [Formula: see text] ion-pair formations are reported for the first time. Simultaneous production of positive and negative ions is seen to be a common mechanism by electron impact. Appearance energies of some fragments are several electron volts lower than those of previous works.

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