Extracellular antibacterial substances in Anabaena fertilissima CCC597 kill bacteria by triggering oxidative radicals and destroying membrane integrity

Nova Hedwigia ◽  
2020 ◽  
Vol 110 (3) ◽  
pp. 247-267
Author(s):  
Trashi Singh ◽  
Pushpendra Kumar Dwivedi ◽  
Suvendra Nath Bagchi
Keyword(s):  
Cytoplasmic Membrane ◽  
Unsaturated Fatty Acids ◽  
Membrane Integrity ◽  
Antibacterial Properties ◽  
Axenic Culture ◽  
Test Organism ◽  
Concomitant Increase ◽  
Anabaena Fertilissima ◽  
Membrane Bound ◽  
Cytosolic Acidification

An axenic culture of a cyanobacterium in the spent medium produced hexane-extracta- ble compound(s) that antagonized growth of several Gram+ve and –ve bacteria, including a few potential pathogens. Phylogenetic investigations classified the strain to be Anabaena fertilissima strain CCC597. Using Escherichia coli MTCC443 as a test organism, we have shown that ROS (O 2; H 2O 2) production and outer and inner membrane (OM: IM) permeabilization were induced upon such treatments. Consequently, leakage of proteins and cytosolic acidification processes were initi- ated. Suppression of cytoplasmic membrane-bound respiratory O 2consumption was most likely the physiological aberration that killed the bacteria. Several antioxidant enzymes viz. superoxide dis- mutase, catalase, and peroxidases showed concomitant increase in the enzymatic activities and band intensities in the corresponding substrate gels. Notwithstanding, the counteraction mechanism(s) was not preventive, and sufficient oxidative radicals still generated to manifest lipid peroxidation. Chemical analysis of the hexane-extract of A. fertilissima culture filtrates revealed presence of a number of long chain unsaturated fatty acids, including cis-13,16-docosadienoic acid, with proven antibacterial properties.

scholarly journals CBMT-17. DEFECTIVE QKI-DEPENDENT LIPID METABOLISM INDUCES GENOMIC INSTABILITY AND SENSITIZES GLIOBLASTOMA TO IMMUNOTHERAPY

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi36-vi36
Author(s):  
Takashi Shingu ◽  
Jian Hu
Keyword(s):  
Genomic Instability ◽  
Mitochondrial Membrane ◽  
Rna Binding ◽  
Cytoplasmic Membrane ◽  
Unsaturated Fatty Acids ◽  
Rna Stability ◽  
Membrane Integrity ◽  
Immune Checkpoints ◽  
Mitochondrial Defects ◽  
And Function

Abstract Despite transformative effects on the therapy of cancers such as melanoma and lung adenocarcinoma, blockade of the T cell immune checkpoints has generated limited impact on glioblastoma. Identifying genetic/genomic alterations that could potentially sensitize the patients to immunotherapy will significantly improve the efficacy of immunotherapy on glioblastoma patients. As part of our effort to identify novel glioma suppressors that affect the interaction of GSCs with their microenvironment, we discovered that the RNA-binding protein Quaking (QKI) is a key regulator of cellular endocytosis. QKI is mutated or deleted in ~34% of human glioblastomas. Supporting QKI’s tumor suppresser function, 92% of the Nestin-CreERT2;QkiL/L;PtenL/L;p53L/L mice developed glioblastoma with a median survival of 105 days, however, the Nestin-CreERT2;PtenL/L;p53L/L mice did not develop any glioma up to a year. Mechanistically, QKI regulates the RNA stability and alternative splicing of numerous protein and lipid components of endolysosomes, particularly the unsaturated fatty acids (UFAs). Functionally, deletion of Qki and inhibition of UFA biosynthesis both decrease endolysosome-mediated receptor degradation, thereby enriching receptors on the cytoplasmic membrane (e.g., Frizzled and Notch1) that are essential for maintaining stemness. This enrichment of receptor signaling enables GSCs to cope with the low ligand levels during their invasion. On the other hand, lower lysosomal activity induced by Qki deletion and UFA loss led to defective mitophagy. We also found that insufficient UFAs in mitochondrial membrane significantly compromised mitochondrial membrane integrity and function. These two mechanisms concomitantly led to accumulation of damaged mitochondria and higher levels of reactive oxygen species (ROS), and consequently genomic instability. Lastly, we found that the higher level of genomic instability induced by Qki loss rendered cells more sensitive to anti-CTLA4 and anti-PD1 antibodies. Taken together, our data suggest that Qki/UFA loss-induced endolysosomal and mitochondrial defects promote gliomagenesis yet render cells vulnerabilities that could be harnessed for therapeutic purposes.

scholarly journals Biological Properties of Novel Antistaphylococcal Quinoline-Indole Agents

2003 ◽  
Vol 47 (2) ◽  
pp. 458-466 ◽  
Author(s):  
Brunello Oliva ◽  
Keith Miller ◽  
Nico Caggiano ◽  
Alexander J. O'Neill ◽  
Gregory D. Cuny ◽  
...  
Keyword(s):  
Cytoplasmic Membrane ◽  
Membrane Integrity ◽  
Antibacterial Properties ◽  
Biological Properties ◽  
Membrane Function ◽  
Structure Activity ◽  
Methoxy Substituent ◽  
Bactericidal Activities ◽  
Resistance Mutants ◽  
Basic Amine

ABSTRACT The antibacterial properties of novel quinoline-indole (QI) agents were examined. QI agents demonstrated potent bactericidal activities against Staphylococcus aureus, killing by lytic and nonlytic mechanisms. S. aureus mutants resistant to a lytic QI agent (SEP 155342) and a nonlytic QI agent (SEP 118843) arose at frequencies of 1.4 × 10−9 and 1.2 × 10−8, respectively, by selection at four times the MICs. Mutants resistant to QI agent SEP 155342 were unstable, but mutants resistant to QI agent SEP 118843 displayed stable resistance. Mutants resistant to QI agent SEP 118843 were not cross resistant to other inhibitors, including QI agent SEP 155342. Addition of QI agents SEP 118843 and SEP 155342 at four times the MIC caused nonspecific inhibition of several macromolecular biosynthetic pathways in S. aureus. Within 10 min, QI agents SEP 118843 and SEP 155342 both interfered with bacterial membrane integrity, as measured by uptake of propidium iodide. Agents from the two classes of the QI agents probably kill staphylococci by separate mechanisms which, nevertheless, both involve interference with cytoplasmic membrane function. Precise structure-activity relationships for the division of QI agents into two classes could not be determined. However, lytic activity was often associated with substitution of a basic amine at position 4 of the quinoline nucleus, whereas compounds with nonlytic activity usually contained an aromatic ring with or without a methoxy substituent at position 4. Nonlytic QI agents such as SEP 118843 may possess selective activity against the prokaryotic membrane since this compound failed to lyse mouse erythrocytes when it was added at a concentration equivalent to four times the MIC for S. aureus.

IMPACT OF SORBITOL- INDUCED OSMOTIC STRESS ON SOME BIOCHEMICAL TRAITS OF POTATO IN VITRO

2020 ◽  
Vol 51 (4) ◽  
pp. 1038-1047
Author(s):  
Mawia & et al.
Keyword(s):  
Ascorbic Acid ◽  
Osmotic Stress ◽  
Cytoplasmic Membrane ◽  
Genotypic Variation ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Culture Collection ◽  
Nutritive Medium ◽  
Starting Point

This study had as principal objective identification of osmotic-tolerant potato genotypes by using "in vitro" tissue culture and sorbitol as a stimulating agent, to induce water stress, which was added to the  culture nutritive medium in different concentration (0,50, 110, 220, 330 and 440 mM).  The starting point was represented by plantlets culture collection, belonging to eleven potato genotypes: Barcelona, Nectar, Alison, Jelly, Malice, Nazca, Toronto, Farida, Fabulla, Colomba and Spunta. Plantlets were multiplied between two internodes to obtain microcuttings (in sterile condition), which were inoculated on medium. Sorbitol-induced osmotic stress caused a significant reduction in the ascorbic acid, while the concentration of proline, H2O2 and solutes leakage increased compared with the control. Increased the proline content prevented lipid peroxidation, which played a pivotal role in the maintenance of membrane integrity under osmotic stress conditions. The extent of the cytoplasmic membrane damage depends on osmotic stress severity and the genotypic variation in the maintenance of membranes stability was highly associated with the ability of producing more amounts of osmoprotectants (proline) and the non-enzymic antioxidant ascorbic acid in response to osmotic stress level. The results showed that the genotypes Jelly, Nectar, Allison, Toronto, and Colomba are classified as highly osmotic stress tolerant genotypes, while the genotypes Nazca and Farida are classified as osmotic stress susceptible ones.

scholarly journals Evaluating the Antimicrobial Activity of Commercially Available Herbal Toothpastes on Microorganisms Associated with Diabetes Mellitus

2013 ◽  
Vol 14 (5) ◽  
pp. 924-929 ◽  
Author(s):  
Reena Kulshrestha ◽  
J Kranthi ◽  
P Krishna Rao ◽  
Feroz Jenner ◽  
V Abdul Jaleel ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Antimicrobial Activity ◽  
Dental Health ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Test Organism ◽  
Diffusion Method ◽  
Zone Of Inhibition ◽  
Disk Diffusion Method

ABSTRACT Aim The present study was conducted to evaluate the efficacy of commercially available herbal toothpastes against the different periodontopathogens. Materials and methods Six herbal toothpastes that were commonly commercially available were included in the study. Colgate herbal, Babool, Meswak, Neem active, Dabur red toothpastes were tested for the study whereas sterile normal saline was used as control. Antimicrobial efficacies of dentifrices were evaluated against Streptococcus mutans and Actinobacillus actinomycetemcomitans. The antimicrobial properties of dentifrices were tested by measuring the maximum zone of inhibition at 24 hours on the Mueller Hinton Agar media inoculated with microbial strain using disk diffusion method. Each dentifrice was tested at 100% concentration (full strength). Results The study showed that all dentifrices selected for the study were effective against the entire test organism but to varying degree. Neem active tooth paste gave a reading of 25.4 mm as the zone of inhibition which was highest amongst all of the test dentifrices. Colgate Herbal and Meswak dentifrices recorded a larger maximum zone of inhibition, measuring 23 and 22.6 mm respectively, compared to other toothpastes. All other dentifrices showed the zone of inhibition to be between 17 and 19 mm respectively. Conclusion The antibacterial properties of six dentifrices were studied in vitro and concluded that almost all of the dentifrices available commercially had antibacterial properties to some extent to benefit dental health or antiplaque action. How to cite this article Jenner F, Jaleel VA, Kulshrestha R, Maheswar G, Rao PK, Kranthi J. Evaluating the Antimicrobial Activity of Commercially Available Herbal Toothpastes on Microorganisms Associated with Diabetes Mellitus. J Contemp Dent Pract 2013;14(5):924-929.

scholarly journals The effects of anions on fumarate reductase isolated from the cytoplasmic membrane of Escherichia coli

1981 ◽  
Vol 199 (3) ◽  
pp. 473-477 ◽  
Author(s):  
J J Robinson ◽  
J H Weiner
Keyword(s):  
Escherichia Coli ◽  
Cytoplasmic Membrane ◽  
Chemical Properties ◽  
Fumarate Reductase ◽  
Maximal Velocity ◽  
Nitrobenzoic Acid ◽  
Thiol Reagent ◽  
Membrane Bound ◽  
Physical And Chemical ◽  
And Chemical Properties

A broad range of anions was shown to stimulate the maximal velocity of purified fumarate reductase isolated from the cytoplasmic membrane of Escherichia coli, while leaving the Km for fumarate unaffected. Reducing agents potentiate the effects of anions on the activity, but have no effect by themselves. Thermal stability, conformation as monitored by circular dichroism and susceptibility to the thiol reagent 5,5′-dithiobis-(2-nitrobenzoic acid) are also altered by anions. The apparent Km for succinate in the reverse reaction (succinate dehydrogenase activity) varies as a function of anion concentration, but the maximal velocity is not affected. The membrane-bound activity is not stimulated by anions and its properties closely resemble those of the purified enzyme in the presence of anions. Thus it appears that anions alter the physical and chemical properties of fumarate reductase, so that it more closely resembles the membrane-bound form.

scholarly journals Identification and Analysis of Bacterial Protein Secretion Inhibitors Utilizing a SecA-LacZ Reporter Fusion System

2000 ◽  
Vol 44 (6) ◽  
pp. 1418-1427 ◽  
Author(s):  
L. E. Alksne ◽  
P. Burgio ◽  
W. Hu ◽  
B. Feld ◽  
M. P. Singh ◽  
...  
Keyword(s):  
Protein Secretion ◽  
Antimicrobial Agents ◽  
Membrane Integrity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Reporter Construct ◽  
Central Protein ◽  
Bona Fide ◽  
Membrane Bound ◽  
Protein Components

ABSTRACT Protein secretion is an essential process for bacterial growth, yet there are few if any antimicrobial agents which inhibit secretion. An in vivo, high-throughput screen to detect secretion inhibitors was developed based on the translational autoregulation of one of the central protein components, SecA. The assay makes use of a SecA-LacZ fusion reporter construct in Escherichia coli which is induced when secretion is perturbed. Several compounds, including two natural product extracts, which had the ability to induce the reporter fusion were identified and the MICs of these compounds forStaphylococcus aureus strain MN8 were found to be ≤128 μg/ml. Enzyme-linked immunosorbent assay, Western blotting, and immunoprecipitation techniques were used to analyze the affects of these compounds on protein secretion. Six representative compounds presented here appear to be bona fide secretion inhibitors but were found to have deleterious effects on membranes. It was concluded that, while the method described here for identifying inhibitors of secretion is valid, screens such as this, which are directed against the membrane-bound portion of a pathway, may preferentially identify compounds which affect membrane integrity.

scholarly journals The Involvement of Energy Metabolism and Lipid Peroxidation in Lignin Accumulation of Postharvest Pumelos

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 269
Author(s):  
Huiling Yan ◽  
Junjia Chen ◽  
Juan Liu
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Energy Metabolism ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Energy Charge ◽  
Succinic Dehydrogenase ◽  
Membrane Integrity ◽  
Lignin Accumulation ◽  
Juice Sacs

Lignification is especially prominent in postharvest pumelo fruit, which greatly impairs their attractiveness and commercial value. This study investigated the energy metabolism and lipid peroxidation and their relationship with accumulated lignin content in juice sacs of “Hongroumiyou” (HR) during 90 d of storage at 25 °C. The results indicated that, the alterations of energy metabolism in juice of sacs of postharvest pumelos was featured by a continuous decline in energy charge and ATP/ADP; an increase in succinic dehydrogenase (SDH) activity before 30 d and increases in activities of cytochrome c oxidase (CCO) and F0F1-ATPase before 60 d; but declines in activities of Ca2+-ATPase and H+-ATPase. Additionally, enhanced contents of H2O2, O2−, and –OH scavenging rate; increased malondialdehyde (MDA) content; and transformation of unsaturated fatty acids (USFA) to saturated fatty acids (USFA) and reduced USFA/SFA (U/S) could result in lipid peroxidation and membrane integrity loss. Moreover, correlation analysis showed that lignin accumulation was in close relation to energy metabolism and lipid peroxidation in juice sacs of postharvest pumelos. These results gave evident credence for the involvement of energy metabolism and lipid peroxidation in the lignin accumulation of HR pumelo fruit during postharvest storage.

scholarly journals Hex1, the Major Component of Woronin Bodies, Is Required for Normal Development, Pathogenicity, and Stress Response in the Plant Pathogenic Fungus Verticillium dahliae

2020 ◽  
Vol 6 (4) ◽  
pp. 344
Author(s):  
Vasileios Vangalis ◽  
Ioannis A. Papaioannou ◽  
Emmanouil A. Markakis ◽  
Michael Knop ◽  
Milton A. Typas
Keyword(s):  
Stress Response ◽  
Verticillium Dahliae ◽  
Pathogenic Fungus ◽  
Membrane Integrity ◽  
Fungal Growth ◽  
Growth Physiology ◽  
Cellular Processes ◽  
Ros Homeostasis ◽  
Membrane Bound ◽  
Septal Pores

Woronin bodies are membrane-bound organelles of filamentous ascomycetes that mediate hyphal compartmentalization by plugging septal pores upon hyphal damage. Their major component is the peroxisomal protein Hex1, which has also been implicated in additional cellular processes in fungi. Here, we analyzed the Hex1 homolog of Verticillium dahliae, an important asexual plant pathogen, and we report its pleiotropic involvement in fungal growth, physiology, stress response, and pathogenicity. Alternative splicing of the Vdhex1 gene can lead to the production of two Hex1 isoforms, which are structurally similar to their Neurospora crassa homolog. We show that VdHex1 is targeted to the septum, consistently with its demonstrated function in sealing hyphal compartments to prevent excessive cytoplasmic bleeding upon injury. Furthermore, our investigation provides direct evidence for significant contributions of Hex1 in growth and morphogenesis, as well as in asexual reproduction capacity. We discovered that Hex1 is required both for normal responses to osmotic stress and factors that affect the cell wall and plasma-membrane integrity, and for normal resistance to oxidative stress and reactive oxygen species (ROS) homeostasis. The Vdhex1 mutant exhibited diminished ability to colonize and cause disease on eggplant. Overall, we show that Hex1 has fundamentally important multifaceted roles in the biology of V. dahliae.

scholarly journals Characterization of Cytoplasmic / Membrane-Bound Protein Mixtures by Z-Scan Fluorescence Fluctuation Spectroscopy

2011 ◽  
Vol 100 (3) ◽  
pp. 470a
Author(s):  
Elizabeth M. Smith ◽  
Patrick J. Macdonald ◽  
Yan Chen ◽  
Joseph P. Albanesi ◽  
Joachim D. Mueller
Keyword(s):  
Cytoplasmic Membrane ◽  
Fluorescence Fluctuation Spectroscopy ◽  
Membrane Bound

scholarly journals Membrane-bound lactate dehydrogenases and mandelate dehydrogenases of Acinetobacter calcoaceticus. Location and regulation of expression

1985 ◽  
Vol 227 (3) ◽  
pp. 753-757 ◽  
Author(s):  
N Allison ◽  
M J O'Donnell ◽  
M E Hoey ◽  
C A Fewson
Keyword(s):  
Lactate Dehydrogenase ◽  
Cytoplasmic Membrane ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Acinetobacter Calcoaceticus ◽  
Regulation Of Expression ◽  
Ionic Detergents ◽  
Membrane Bound ◽  
Lactate Dehydrogenases ◽  
Triton X

Acinetobacter calcoaceticus possesses an L(+)-lactate dehydrogenase and a D(-)-lactate dehydrogenase. Results of experiments in which enzyme activities were measured after growth of bacteria in different media indicated that the two enzymes were co-ordinately induced by either enantiomer of lactate but not by pyruvate, and repressed by succinate or L-glutamate. The two lactate dehydrogenases have very similar properties to L(+)-mandelate dehydrogenase and D(-)-mandelate dehydrogenase. All four enzymes are NAD(P)-independent and were found to be integral components of the cytoplasmic membrane. The enzymes could be solubilized in active form by detergents; Triton X-100 or Lubrol PX were particularly effective D(-)-Lactate dehydrogenase and D(-)-mandelate dehydrogenase could be selectively solubilized by the ionic detergents cholate, deoxycholate and sodium dodecyl sulphate.

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