scholarly journals Antimicrobial Activity of Euplotin C, the Sesquiterpene Taxonomic Marker from the Marine Ciliate Euplotes crassus

2004 ◽  
Vol 48 (10) ◽  
pp. 3828-3833 ◽  
Author(s):  
Dianella Savoia ◽  
Claudio Avanzini ◽  
Tiziano Allice ◽  
Emanuela Callone ◽  
Graziano Guella ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Leishmania Major ◽  
Lethal Dose ◽  
J774 Cell ◽  
Marine Ciliate ◽  
Euplotes Crassus ◽  
Taxonomic Marker ◽  
Solubility Enhancers ◽  
J774 Cell Line ◽  
Lethal Doses

ABSTRACT Strains of the marine ciliate protist Euplotes crassus produce exclusive terpenoids called euplotins that play an ecological role. Among these derivatives, euplotin C is the main of four secondary metabolites isolated from cultures of this protozoon and represents the sesquiterpene taxonomic marker from E. crassus. Because different terpenoid metabolites of plant origin showed a certain antimicrobial activity, we assessed the compound euplotin C, purified by high-pressure liquid chromatography and solubilized in two solubility enhancers, against the protozoa Leishmania major and Leishmani infantum, the fungus Candida albicans, and nine strains of gram-positive and gram-negative microorganisms. An activity of euplotin C against Leishmania promastigotes was demonstrated (50% lethal doses were 4.6 or 8.1 μg/ml depending on the agent used to solubilize the compound), while the effect was less evident on Candida and nearly absent on bacteria. A nonsignificant cytotoxicity (50% lethal dose, >200 μg/ml) against the J774 cell line was observed. A leishmanicidal activity was also shown by the living, euplotin-producing cells of E. crassus cultured together with promastigotes; this activity increased with time from 10 min to 6 h of incubation. This study provides an initial rationale for the evaluation of euplotin C and other similar natural products as alternative or possibly synergistic compounds for current antiprotozoon chemotherapeutics.

Evaluation of the Cytotoxicity Effect of Chaerophyllum Extract on Leishmania major and J774 Cell Line in Vitro

2016 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Parisa Ebrahimisadr ◽  
Hamidreza Majidiani ◽  
Farahnaz Bineshian ◽  
Farnoosh Jameie ◽  
Ezatollah Ghasemi ◽  
...  
Keyword(s):  
Cell Line ◽  
Leishmania Major ◽  
J774 Cell ◽  
J774 Cell Line

scholarly journals Prostaglandin E2Receptor Antagonist with Antimicrobial Activity against Methicillin-ResistantStaphylococcus aureus

2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Mélanie A. C. Ikeh ◽  
Paul L. Fidel ◽  
Mairi C. Noverr
Keyword(s):  
Antimicrobial Activity ◽  
Receptor Antagonist ◽  
Enzyme Inhibitors ◽  
Lethal Dose ◽  
Prostaglandin E ◽  
Protective Effects ◽  
Physiological Concentration ◽  
Content Type ◽  
Abdominal Infections

ABSTRACTPolymicrobial intra-abdominal infections (IAI) involvingCandida albicansandStaphylococcus aureusare associated with severe morbidity and mortality (∼80%). Our laboratory discovered that the immunomodulatory eicosanoid prostaglandin E2(PGE2) plays a key role in the lethal inflammatory response during polymicrobial IAI using a mouse model of infection. In studies designed to uncover key PGE2biosynthesis/signaling components involved in the response, selective eicosanoid enzyme inhibitors and receptor antagonists were selected and prescreened for antimicrobial activity againstC. albicansorS. aureus. Unexpectedly, we found that the EP4receptor antagonist L-161,982 had direct growth-inhibitory effects onS. aureusin vitroat the physiological concentration required to block the PGE2interaction with EP4. This antimicrobial activity was observed with methicillin-sensitiveS. aureusand methicillin-resistantS. aureus(MRSA) strains, with the MIC and minimum bactericidal concentration values for planktonic cells being 50 μg/ml and 100 μg/ml, respectively. In addition, L-161,982 inhibitedS. aureusbiofilm formation and had activity against preformed mature biofilms. More importantly, treatment of mice with L-161,982 following intraperitoneal inoculation with a lethal dose of MRSA significantly reduced the bioburden and enhanced survival. Furthermore, L-161,982 protected mice against the synergistic lethality induced by coinfection withC. albicansandS. aureus. The antimicrobial activity of L-161,982 is independent of EP4receptor inhibitory activity; an alternative EP4receptor antagonist exerted no antimicrobial or protective effects. Taken together, these findings demonstrate that L-161,982 has potent antimicrobial activity against MRSA and may represent a significant therapeutic alternative in improving the prognosis of mono- or polymicrobial infections involving MRSA.

scholarly journals A SPECIFIC POISON IN THE LIVER EXTRACTS OF RABBITS INOCULATED WITH TYPHOID AND PRODIGIOSUS BACILLI INTRAVENOUSLY

1918 ◽  
Vol 28 (5) ◽  
pp. 571-583
Author(s):  
Julia T. Parker
Keyword(s):  
Anaphylactic Shock ◽  
Liver Extract ◽  
Lethal Dose ◽  
Toxic Substance ◽  
Normal Liver ◽  
Immune Serum ◽  
Minimum Lethal Dose ◽  
Lethal Doses

1. The livers of rabbits inoculated with cultures of Bacillus typhosus or Bacillus prodigiosus under certain conditions contain a toxic substance extractable with salt solution. When the toxic extracts are injected intravenously into normal rabbits the latter animals develop symptoms resembling those of anaphylactic shock and succumb. The lethal doses of the toxic extracts are far smaller than those of normal liver extract. 2. The livers of rabbits injected with typhoid antigen also yield a toxic extract. 3. Boiling as well as filtration through a Berkefeld filter only partially detoxicates the extract. 4. Tolerance to one to two lethal doses of the poisonous extracts can be induced by cautious immunization. 5. Rabbits actively immunized to Bacillus typhosus or Bacillus prodigiosus usually resist one lethal dose of the homologous liver poison; and animals tolerant to the typhoid liver poison resist one minimum lethal dose at least of Bacillus typhosus. 6. Typhoid immune serum is not detoxicating either in vivo or in vitro for the typhoid liver poison. 7. The liver poisons are specific, since rabbits actively immunized to either Bacillus typhosus or Bacillus prodigiosus withstand at least one minimum lethal dose of the homologous but not of the heterologous-liver poisons.

scholarly journals Efficient synthesis of (R)-harmonine – the toxic principle of the multicolored Asian lady beetle (Harmonia axyridis)

2015 ◽  
Vol 13 (18) ◽  
pp. 5139-5146 ◽  
Author(s):  
Nadja C. Nagel ◽  
Anita Masic ◽  
Uta Schurigt ◽  
Wilhelm Boland
Keyword(s):  
Antimicrobial Activity ◽  
Leishmania Major ◽  
Harmonia Axyridis ◽  
Lady Beetle ◽  
Efficient Synthesis ◽  
Toxic Principle ◽  
Asian Lady Beetle ◽  
Multicolored Asian Lady Beetle

An efficient and flexible synthesis of (R)-harmonine and putative biosynthetic precursors has been developed. Furthermore, its antimicrobial activity againstLeishmania majoris demonstrated.

The Cumulative Toxicity of Diniteo-O-cresol applied in Small Doses to Locusts

1957 ◽  
Vol 48 (2) ◽  
pp. 435-445 ◽  
Author(s):  
R. D. MacCuaig ◽  
K. F. Sawyer
Keyword(s):  
Single Dose ◽  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Lethal Dose ◽  
Cumulative Effect ◽  
Lethal Effect ◽  
Substantial Contribution ◽  
Successful Operation ◽  
Relative Susceptibility ◽  
Lethal Doses

SummaryBy the method of attacking flying swarms of locusts with insecticides sprayed directly into the swarm by relays of light aircraft, a proportion of the swarm receives a sub-lethal dose from each sortie. For successful operation it is essential that a substantial contribution to the final mortality should be produced by the accumulation of these sub-lethal doses on individual insects over a period of time. The object of the present experiments was to determine whether such doses applied at intervals are wholly additive in their effects. The poison used was dinitro-o-cresol (Mk. IV DNC solution) and to shorten the experimental procedure, the locusts, Schistocerca gregaria (Forsk.) and Locusta migratoria migratorioides (R. & F.), were dosed by means of a single drop of poison applied to the ventral surface of the abdomen by a micro-drop syringe.When locusts are given regular daily doses of DNC the doses are not wholly cumulative in their effect. After the second or third day the lethal effect of each dose becomes steadily less, and after the fourth or fifth day it tends to zero, representing a steady state in which the rates of application and loss of insecticidal activity in the survivors are equal.When the dose is applied in two halves with various time intervals between them, the cumulative effect during the first 24 hours is less in S. gregaria than in L. migratoria. In the latter species it is possible that sensitisation occurs. After three days, the first half-dose has fallen to an estimated 20 per cent, of its initial effectiveness in each species.These two species are equally susceptible to a single dose expressed as μg. DNC/g. body weight. The females are more resistant than the males to daily doses (relative susceptibility in S. gregaria, 1·54) but probably not to single doses (relative susceptibility, 1·09).Resistance to a daily dose correlates roughly with resistance to a single dose, the total dose required to produce 50 per cent, mortality in four days being about twice the LD50 for a single dose.If flight activity does not materially alter the present results, it is evident that the non-cumulative effects of sub-lethal doses could cause a serious loss in the efficiency of an air-spray operation if it were unduly prolonged. Thus a quantity of insecticide sufficient to kill over 99 per cent, of the locusts if applied as a single dose would kill less than 40 per cent, if the application were spread over four days.

scholarly journals Influence of functional groups on toxicity of carbon nanomaterials: implication for toxicological evolution during atmospheric relevant aging of soot

2019 ◽  
Author(s):  
Yongchun Liu ◽  
Haotian Jiang ◽  
Chunmei Liu ◽  
Lian Wang ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Decay Rate ◽  
Cell Line ◽  
Black Carbon ◽  
Carbon Nanomaterials ◽  
Control Sample ◽  
Oxidation Potential ◽  
Single Wall Carbon Nanotubes ◽  
J774 Cell ◽  
J774 Cell Line

Abstract. It has been well recognized that black carbon is toxic for human health, while it is still controversial about the influence of functionalization on its toxicity as well as the evolution of its toxicity due to chemical aging in the atmosphere. In the current study, the oxidation potential measured by dithiothreitol (DTT) decay rate and the cytotoxicity to murine macrophage cells of different functionalized carbon nanomaterials, which were used as model sample of black carbon, were investigated for understanding the role of functionalization in the toxicity of black carbon. The DTT decay rates of special black 4A (SB4A), graphene, graphene oxide, single wall carbon nanotubes (SWCNT), SWCNT-OH and SWCNT-COOH were 45.9±3.0, 58.5±6.6, 160.7±21.7, 38.9±8.9, 57.0±7.2 and 36.7±0.2 pmol min−1 μg−1, respectively. Epoxide was found to be mainly responsible for the largest DTT decay rate of graphene oxide compared with other materials based on comprehensive characterizations. Both carboxylation and hydroxylation showed little influence on the oxidation potential of these materials, while epoxidation contributes to the enhancement of oxidation potential. All these carbon nanomaterials were toxic to murine J774 cell line. However, oxidized carbon nanomaterials (graphene oxide, SWCNT-OH and SWCNT-COOH) showed weaker cytotoxicity to J774 cell line compared with the corresponding control sample as far as the metabolic activity was considered and stronger cytotoxicity to J774 cell line regarding to the membrane integrity and DNA incorporation. These results imply that epoxidation might enhance the oxidation potential of black carbon during transport in the atmosphere.

A Comparison of Ecotoxicological Tests

2002 ◽  
Vol 30 (5) ◽  
pp. 539-550 ◽  
Author(s):  
James L. Botsford
Keyword(s):  
Lethal Dose ◽  
Correlation Coefficients ◽  
Rat Hepatocytes ◽  
In Vitro Cytotoxicity ◽  
Test Results ◽  
Average Correlation ◽  
Ecotoxicological Tests ◽  
Present Test ◽  
Lethal Doses

A simple, inexpensive and rapid method of determining toxicity by using a bacterium as the indicator organism was developed and compared with 23 other tests. The average correlation coefficient when comparing these 23 tests with the present test was 0.800, ranging from 0.580 to 0.950. Eleven of the tests were compared in detail by using 35 of the chemicals on the Multicentre Evaluation of In Vitro Cytotoxicity list of test chemicals. Comparing results from the present test with test results for these 35 chemicals with Microtox™, Biotox™, Daphnia magna, rat hepatocytes and ascites tumour cell resulted in correlation coefficients ranging from 0.871 to 0.933. Comparisons of the test data with rodent LD50 values, human lethal dose estimates from autopsies and human lethal doses obtained from the literature provided correlation coefficients ranging from 0.580 to 0.770, indicating that the test compares less favourably with these methods. This test provides data comparable to data from other ecotoxicological tests.

In vivo protection studies of bis-quaternary 2-(hydroxyimino)-N-(pyridin-3-yl) acetamide derivatives against sarin poisoning in mice

2016 ◽  
Vol 36 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Devyani Swami ◽  
Hitendra N Karade ◽  
Jyotiranjan Acharya ◽  
Pravin Kumar
Keyword(s):  
Time Course ◽  
Lethal Dose ◽  
Nerve Agent ◽  
Ache Inhibition ◽  
Inhibition Concentration ◽  
Time Course Study ◽  
Dose Dependent ◽  
Protection Index ◽  
Lethal Doses

In vivo antidotal efficacy of new bis- quaternary 2-(hydroxyimino)- N-(pyridin-3yl) acetamide derivatives (HNK series), to counter multiples of lethal doses of nerve agent sarin (GB) and reactivation of acetylcholinesterase (AChE), was evaluated in Swiss albino mice. [Protection index PI; median lethal dose (LD50) of sarin with treatment/LD50 of sarin] was estimated, using 0.05, 0.10, and 0.20 LD50 as treatment doses of all the oximes with atropine against sarin poisoning. Dose-dependent time course study was conducted at 0.2, 0.4 and 0.8 LD50 dose of sarin for estimating maximum AChE inhibition. At optimized time (15 min), in vivo enzyme half inhibition concentration (IC50) was calculated. AChE reactivation efficacy of HNK series and pralidoxime (2-PAM) were determined by plotting shift of log IC50 doses. HNK-102 with atropine showed three fold higher PI compared to 2-PAM. In vivo IC50 of sarin for brain and serum AChE was found to be 0.87 LD50 (139.2 µg/kg) and 0.48 LD50 (77.23 µg/kg), respectively. Treatment with HNK-102 and HNK-111 (equal to their 0.20LD50) significantly reactivated sarin-intoxicated AChE ( p < 0.05) at 2× IC50 dose of sarin, compared to 2-PAM. The study revealed that HNK-102 oxime was three times more potent as antidote, for acute sarin poisoning compared to 2-PAM in vivo.

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