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1.
J Biomed Sci ; 30(1): 67, 2023 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-37574554

RESUMEN

Beyond the development of resistance, the effects of antibiotics on bacteria and microbial communities are complex and far from exhaustively studied. In the context of the current global antimicrobial resistance crisis, understanding the adaptive and physiological responses of bacteria to antimicrobials is of paramount importance along with the development of new therapies. Bacterial dependence on antibiotics is a phenomenon in which antimicrobials instead of eliminating the pathogens actually provide a boost for their growth. This trait comprises an extreme example of the complexities of responses elicited by microorganisms to these drugs. This compelling evolutionary trait was readily described along with the first wave of antibiotics use and dependence to various antimicrobials has been reported. Nevertheless, current molecular characterizations have been focused on dependence on vancomycin, linezolid and colistin, three critically important antibiotics frequently used as last resource therapy for multi resistant pathogens. Outstanding advances have been made in understanding the molecular basis for the dependence to vancomycin, including specific mutations involved. Regarding linezolid and colistin, the general physiological components affected by the dependence, namely ribosomes and membrane function respectively, have been established. Nonetheless the implications of antibiotic dependence in clinically relevant features, such as virulence, epidemics, relationship with development of resistance, diagnostics and therapy effectiveness require clarification. This review presents a brief introduction of the phenomenon of bacterial dependence to antibiotics and a summary on early and current research concerning the basis for this trait. Furthermore, the available information on the effect of dependence in key clinical aspects is discussed. The studies performed so far underline the need to fully disclose the biological and clinical significance of this trait in pathogens to successfully assess its role in resistance and to design adjusted therapies.


Asunto(s)
Antibacterianos , Venenos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Vancomicina/farmacología , Linezolid/farmacología , Linezolid/uso terapéutico , Colistina/farmacología , Venenos/farmacología , Bacterias/genética , Pruebas de Sensibilidad Microbiana , Farmacorresistencia Bacteriana
2.
Pest Manag Sci ; 78(4): 1698-1706, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34994495

RESUMEN

BACKGROUND: Pesticides can be noxious to non-target beneficial arthropods and their negative effects have been recently recognized even at low doses. The predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) plays an important role in controlling insect pests in solanaceous crops, but its concurrent herbivory often poses relevant concerns for tomato production. Although insecticide side effects on N. tenuis have been previously studied, little is known on the potential implications of neurotoxic chemicals at low concentrations. We assessed the baseline toxicity of three neurotoxic insecticides (lambda-cyhalothrin, spinosad and chlorpyrifos) on N. tenuis by topical contact exposure. The behavioral and reproduction capacity of the predator was then investigated upon exposure to three estimated low-lethal concentrations (LC1 , LC10 and LC30 ). RESULTS: Predator survival varied among insecticides and concentrations, with LC30 /label rate ratios ranging from 8.45% to 65.40% for spinosad and lambda-cyhalothrin, respectively. All insecticides reduced the fertility of N. tenuis females at all estimated low-lethal concentrations. Chlorpyrifos seriously compromised predator orientation towards a host plant even at LC1 , while the same effect was observed for lambda-cyhalothrin and spinosad solely at LC30 . Lambda-cyhalothrin (at all concentrations) and chlorpyrifos (at LC10 and LC30 ) also affected the time taken by N. tenuis females to make a choice. CONCLUSION: The results indicate that all three insecticides can be detrimental to N. tenuis and should be avoided when presence of the predator is desirable. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Asunto(s)
Heterópteros , Insecticidas , Venenos , Animales , Femenino , Insecticidas/toxicidad , Control Biológico de Vectores , Venenos/farmacología , Reproducción
3.
Int J Mol Sci ; 16(7): 15235-50, 2015 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-26154765

RESUMEN

Saxitoxin (STX) is a neurotoxin produced by dinoflagellates in diverse species, such as Alexandrium spp., and it causes paralytic shellfish poisoning (PSP) in humans after the ingestion of contaminated shellfish. Recent studies have suggested that the immune functions of bivalves could be affected by harmful algae and/or by their toxins. Herein, hemocytes are the main effector cells of the immune cellular response. In this study, we evaluated the response of hemocytes from the mussel Mytilus chilensis to STX exposure in a primary culture. Cell cultures were characterized according to size and complexity, while reactive oxygen species (ROS) production was evaluated using a dichlorofluorescein diacetate (DCFH-DA) assay. Finally, phagocytic activity was measured using both flow cytometry and fluorescence microscopy assays. Additionally, gene transcription of candidate genes was evaluated by qPCR assays. The results evidenced that exposures to different concentrations of STX (1-100 nM) for 24 h did not affect cell viability, as determined by an MTT assay. However, when hemocytes were exposed for 4 or 16 h to STX (1-100 nM), there was a modulation of phagocytic activity and ROS production. Moreover, hemocytes exposed to 100 nM of STX for 4 or 16 h showed a significant increase in transcript levels of genes encoding for antioxidant enzymes (SOD, CAT), mitochondrial enzymes (COI, COIII, CYTB, ATP6, ND1) and ion channels (K+, Ca2+). Meanwhile, C-type lectin and toll-like receptor genes revealed a bi-phase transcriptional response after 16 and 24-48 h of exposure to STX. These results suggest that STX can negatively affect the immunocompetence of M. chilensis hemocytes, which were capable of responding to STX exposure in vitro by increasing the mRNA levels of antioxidant enzymes.


Asunto(s)
Hemocitos/efectos de los fármacos , Mytilus/efectos de los fármacos , Fagocitosis , Venenos/farmacología , Saxitoxina/farmacología , Transcriptoma , Animales , Hemocitos/inmunología , Hemocitos/metabolismo , Mytilus/inmunología , Mytilus/metabolismo , Estrés Oxidativo , Venenos/toxicidad , Saxitoxina/toxicidad , Transcripción Genética
4.
Int. immunopharmacol ; Int. immunopharmacol;11(9): 1368-1377, 8 Apr, 2011.
Artículo en Inglés | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP, SESSP-IBACERVO | ID: biblio-1063516

RESUMEN

Stingrays from the Potamotrygon cf. henlei species are widely distributed in high numbers throughout therivers of central-west Brazil, being the source of numerous envenomations occurring in the dry season, posinga serious public health problem even if not properly reported. The accidents usually involve fishermen andbathers, and to date there is no effective treatment for the injured. Considering these facts and limitations ofstudies aiming at understanding the effects induced by P. cf. henlei envenoming, this study aimed to describethe principal pharmacological and certain biochemical properties of the mucus and sting venom. We foundthat mucus and sting venom is toxic to mice having nociceptive, edematogenic and proteolysis activities. Ourresults also indicate that the inflammatory cellular influx observed could be triggered by the venom andmucus. Furthermore the venom and mucus were partially purified by solid-phase extraction tested forantimicrobial activity in which only the mucus presented activity. It could be inferred from the present studythat P. cf. henlei venom possesses a diverse mixture of peptides, enzymes and pharmacologically activecomponents.


Asunto(s)
Ratones , Moco , Rajidae/crecimiento & desarrollo , Venenos de los Peces/análisis , Venenos de los Peces/toxicidad , Venenos/análisis , Venenos/farmacología , Venenos/aislamiento & purificación , Venenos/toxicidad , Edema/inducido químicamente , Necrosis/inducido químicamente
5.
Rev. bras. parasitol. vet ; 17(4): 235-238, out.-dez. 2008. ilus, tab
Artículo en Inglés | LILACS | ID: lil-606754

RESUMEN

The purpose of this study was to characterize Eimeria bateri oocysts and to evaluate the aflatoxin effect in the morphometry of sporulated oocysts in Japanese quails infected naturally. Of a total of 50 quails naturally infected by E. bateri were randomly divided into two groups with 25 birds each. In one of them, quails were orally administered with aflatoxin in dose of 0.04 mg/kg body weight previously. Both experimental groups shed E. bateri oocysts. These oocysts were subspherical to ellipsoidal, 25.1 x 18.9 Lim, with bi-layered wall. Micropyle and residuum were absent, but one or more polar granules were present. Sporocysts elongate ovoid, 12.5 x 7.4 μm. Stieda and substieda bodies were present. Sporocyst residuum was dispersed and sporozoites presented a nucleus and a refractile body. Histograms confirmed the presence of a single species, E. bateri. Linear regression proved that E. bateri oocysts are polymorphic, due, basically, to shape of these oocysts. The comparative morphometry between two experimental groups demonstrated that the aflatoxin influenced significantly in the E. bateri oocysts.


O objetivo deste estudo foi caracterizar os oocistos de Eimeria bateri e avaliar o efeito da aflatoxina na morfometria destes oocistos em codornas japonesas naturalmente infectadas. Cinqüenta codornas naturalmente parasitadas por E. bateri foram separadas aleatoriamente em dois grupos com 25 aves cada. Um dos grupos foi intoxicado experimentalmente com aflatoxina, por via oral, na dose de 0,04 mg/kg de peso vivo. Os dois grupos experimentais eliminaram oocistos de E. bateri nas fezes. Esses oocistos foram de subesféricos a elipsóides, 25,1 x 18,9 Lm, com parede dupla. A micrópila e o resíduo estavam ausentes, mas um ou vários grânulos polares estavam presentes. Esporocistos ovóides alongados, 12,5 x 7,4 L m. Os corpos de Stieda e substieda estavam presentes. O resíduo do esporocisto estava disperso e os esporozoítas apresentaram um núcleo e um corpo refráctil. Os histogramas confirmaram a presença de uma única espécie, E. bateri. A regressão linear comprovou que os oocistos de E. bateri são polimórficos, devido, basicamente, à forma desses oocistos. A morfometria comparativa entre os dois grupos experimentais, demonstrou que a aflatoxina influiu significativamente nos oocistos de E. bateri.


Asunto(s)
Animales , Aflatoxinas/farmacología , Coturnix/parasitología , Eimeria , Oocistos/citología , Oocistos/efectos de los fármacos , Venenos/farmacología , Brasil
6.
Rev Bras Parasitol Vet ; 17(4): 235-8, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-19265584

RESUMEN

The purpose of this study was to characterize Eimeria bateri oocysts and to evaluate the aflatoxin effect in the morphometry of sporulated oocysts in Japanese quails infected naturally. Of a total of 50 quails naturally infected by E. bateri were randomly divided into two groups with 25 birds each. In one of them, quails were orally administered with aflatoxin in dose of 0.04 mg/kg body weight previously. Both experimental groups shed E. bateri oocysts. These oocysts were subspherical to ellipsoidal, 25.1 x 18.9 microm, with bi-layered wall. Micropyle and residuum were absent, but one or more polar granules were present. Sporocysts elongate ovoid, 12.5 x 7.4 microm. Stieda and substieda bodies were present. Sporocyst residuum was dispersed and sporozoites presented a nucleus and a refractile body. Histograms confirmed the presence of a single species, E. bateri. Linear regression proved that E. bateri oocysts are polymorphic, due, basically, to shape of these oocysts. The comparative morphometry between two experimental groups demonstrated that the aflatoxin influenced significantly in the E. bateri oocysts.


Asunto(s)
Aflatoxinas/farmacología , Coturnix/parasitología , Eimeria , Oocistos/citología , Oocistos/efectos de los fármacos , Venenos/farmacología , Animales , Brasil
8.
Respir Physiol Neurobiol ; 131(3): 175-87, 2002 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-12126919

RESUMEN

Nitric oxide (NO) produces a dual effect on carotid body (CB) oxygen chemoreception. At low concentration, NO inhibits chemosensory response to hypoxia, while in normoxia, medium and high [NO] increases the frequency of carotid chemosensory discharges (f(x)). Since NO and peroxynitrite inhibit mitochondrial respiration, it is plausible that the NO-induced excitation may depend on the mitochondrial oxidative metabolism. To test this hypothesis, we studied the effects of oligomycin, FCCP and antimycin A that produce selective blockade of hypoxic and NaCN-induced chemosensory responses, leaving nicotinic response less affected. CBs excised from pentobarbitone-anaesthetised cats were perfused in vitro with Tyrode (P(O(2)) approximately 125 Torr, pH 7.40 at 38 degrees C). Hypoxia (P(O(2)) approximately equal 30 Torr), NaCN and nicotine (1-100 microg) and S-nitroso-N-acetylpenicillamide (SNAP, 300-600 microg) increased f(x). Oligomycin (12.5-25 microg), antimycin A (10 microg) and FCCP (5 microM) transiently increased f(x). Subsequently, chemosensory responses to hypoxia, NaCN and SNAP were reduced or abolished, while the response to nicotine was less affected. The electron donor system tetramethyl-p-phenylene diamide and ascorbate that bypasses the electron chain blockade produced by antimycin A, restores the excitatory responses to NaCN and SNAP. Present results suggest that the chemoexcitatory effect of NO depends on the integrity of mitochondrial metabolism.


Asunto(s)
Cuerpo Carotídeo/metabolismo , Células Quimiorreceptoras/metabolismo , Mitocondrias/metabolismo , Óxido Nítrico/metabolismo , Animales , Antibacterianos/farmacología , Antimicina A/farmacología , Ácido Ascórbico/farmacología , Carbonil Cianuro p-Trifluorometoxifenil Hidrazona/farmacología , Cuerpo Carotídeo/efectos de los fármacos , Gatos , Células Quimiorreceptoras/efectos de los fármacos , Depuradores de Radicales Libres/farmacología , Indicadores y Reactivos , Masculino , Mitocondrias/efectos de los fármacos , Oligomicinas/farmacología , Fosforilación Oxidativa/efectos de los fármacos , Venenos/farmacología , Respiración , Cianuro de Sodio/farmacología , Tetrametilfenilendiamina , Desacopladores/farmacología
9.
J Comp Physiol A ; 186(10): 989-97, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11138800

RESUMEN

The non-spiking neurons 151 are present as bilateral pairs in each midbody ganglion of the leech nervous system and they are electrically coupled to several motorneurons. Intracellular recordings were used to investigate how these neurons process input from the mechanosensory P neurons in isolated ganglia. Induction of spike trains (15 Hz) in single P cells evoked responses that combined depolarizing and hyperpolarizing phases in cells 151. The phasic depolarizations, transmitted through spiking interneurons, reversed at around -20 mV. The hyperpolarization had two components, both reversing at around -65 mV, and which were inhibited by strychnine (10 micromol l(-1)). The faster component was transmitted through spiking interneurons and the slower component through a direct P-151 interaction. Short trains (<400 ms) of P cell spikes (15 Hz) evoked the phasic depolarizations superimposed on the hyperpolarization, while long spike trains (>500 ms) produced a succession of depolarizations that masked the hyperpolarizing phase. The amplitude and duration of the hyperpolarization reached their maximum at the initial spikes in a train, while the depolarizations persisted throughout the duration of the stimulus train. Both phases of the response were relatively unaffected by the spike frequency (5-25 Hz). The non-spiking neurons 151 processed the sensory signals in the temporal rather than in the amplitude domain.


Asunto(s)
Sanguijuelas/fisiología , Neuronas Aferentes/fisiología , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Electrofisiología , Ganglios de Invertebrados/citología , Ganglios de Invertebrados/fisiología , Interneuronas/fisiología , Mecanorreceptores/fisiología , Movimiento/fisiología , Venenos/farmacología , Estricnina/farmacología , Sinapsis/fisiología
10.
Rio de Janeiro; Guanabara Koogan; 1980. 1383 p. ilus.
Monografía en Portugués | LILACS | ID: lil-290715
11.
Brain Res ; 845(1): 28-34, 1999 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-10529441

RESUMEN

NaCN is a classical stimulus used to elicit discharges from carotid body chemoreceptors. The effect is assumed to be mediated by glomus (type I) cells, which release an excitatory transmitter for the excitation of carotid nerve endings. Since the sensory perikarya of the glossopharyngeal nerve (from which the carotid nerve branches) are located in the petrosal ganglion, we tested whether application of this drug to the petrosal ganglion superfused in vitro elicits antidromic discharges in the carotid nerve. NaCN did indeed cause an intense and prolonged burst of nerve impulses in the carotid nerve, while provoking a less intense and much briefer burst of discharges in the glossopharyngeal branch. Carotid nerve responses to NaCN were reduced and shortened by prior or following application of dopamine to the ganglion. Sodium azide applied to the petrosal ganglion evoked a less intense and much briefer burst of impulses in the carotid nerve. Ganglionar application of 2,4-dinitrophenol did not induce discharges in the carotid nerve. Switching the superfusion of the ganglion from a normoxic to a hypoxic solution did not evoke discharges in the carotid nerve. Therefore, the perikarya of carotid nerve neurons are sensitive to NaCN, but are not excited by reducing the pO(2) of the superfusing solution.


Asunto(s)
Cuerpo Carotídeo/fisiopatología , Ganglios Sensoriales/fisiopatología , Hipoxia/fisiopatología , 2,4-Dinitrofenol/farmacología , Animales , Cuerpo Carotídeo/efectos de los fármacos , Seno Carotídeo/inervación , Gatos , Dopamina/farmacología , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Potenciales Evocados/fisiología , Ganglios Sensoriales/efectos de los fármacos , Nervio Glosofaríngeo/citología , Nervio Glosofaríngeo/efectos de los fármacos , Nervio Glosofaríngeo/fisiología , Técnicas In Vitro , Oxígeno/farmacología , Venenos/farmacología , Azida Sódica/farmacología , Cianuro de Sodio/farmacología , Estimulación Química , Desacopladores/farmacología
12.
Hepatogastroenterology ; 46(25): 432-5, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10228836

RESUMEN

BACKGROUND/AIMS: Hepatic cirrhosis accompanied by portal hypertension is a common cause of death in human beings. The aim of the present study was to develop an experimental model of hepatic portal hypertension associated with liver damage. METHODOLOGY: To develop liver damage in rats, we used the toxic alkaloid monocrotaline. Two groups of male Wistar rats were used. Group 1 was injected with a single dose of monocrotaline (60 mg/kg of body weight) intraperitoneally. Group 2 was injected with an equal volume of saline solution. After 44 days, the animals underwent the following tests: splenoportography and measurement of portal pressure, hepatic serum biochemical tests, and light and electron microscopy. RESULTS: Group 1 showed a significant increase in splenic pressure, superior and inferior collateral circulation, and an increase in portal vein diameter. Serious alterations were detected in hepatic serum markers. Light microscopy showed different degrees of hepatocyte damage, varying from edema to focal necrosis. Ultrastructural changes were of membrane disruption, mitochondrial and nuclear alterations. CONCLUSIONS: The present experimental model could be useful in establishing the pathophysiological changes associated with portal hypertension due to liver damage.


Asunto(s)
Modelos Animales de Enfermedad , Hipertensión Portal , Cirrosis Hepática Experimental , Monocrotalina/farmacología , Venenos/farmacología , Animales , Hipertensión Portal/inducido químicamente , Hipertensión Portal/complicaciones , Hipertensión Portal/fisiopatología , Cirrosis Hepática Experimental/inducido químicamente , Cirrosis Hepática Experimental/complicaciones , Cirrosis Hepática Experimental/fisiopatología , Masculino , Ratas , Ratas Wistar
13.
Globo Ciência ; 6(70): 35-7, maio 1997. ilus
Artículo en Portugués | Sec. Est. Saúde SP, SESSP-ACVSES | ID: biblio-1063141
17.
Homeopatía [Argent.] ; 57(4): 157-8, 1992.
Artículo en Español | BINACIS | ID: bin-23274

RESUMEN

Esta colaboración trata de explicar lo relativo de los conceptos manejados en relación a los venenos animales y su acción terapéutica homeopática a través de la dinamización hahnemanniana. Las diferencias entre su acción tóxica y patogenética; su justificación a través de los parágrafos 19, 20 y 110 del Organón de Hahnemann. El planteo que otros conceptos son posibles en ciencia y la sugerencia de tender a una epistemología homeopática (AU)


Asunto(s)
Humanos , Animales , Venenos/farmacología , Lachesis muta/efectos adversos , Lachesis muta/uso terapéutico , Cantaridina/toxicidad , Abejas/toxicidad , Abejas/uso terapéutico , Tarentula cubensis/toxicidad , Aranea diadema/toxicidad , Venenos Elapídicos/toxicidad
18.
Homeopatía (B. Aires) ; 57(4): 157-8, 1992.
Artículo en Español | LILACS | ID: lil-157519

RESUMEN

Esta colaboración trata de explicar lo relativo de los conceptos manejados en relación a los venenos animales y su acción terapéutica homeopática a través de la dinamización hahnemanniana. Las diferencias entre su acción tóxica y patogenética; su justificación a través de los parágrafos 19, 20 y 110 del Organón de Hahnemann. El planteo que otros conceptos son posibles en ciencia y la sugerencia de tender a una epistemología homeopática


Asunto(s)
Humanos , Animales , Venenos/farmacología , Cantaridina/toxicidad , /toxicidad , /uso terapéutico , Aranea diadema/toxicidad , Lachesis muta/efectos adversos , Lachesis muta/uso terapéutico , Tarentula cubensis/toxicidad , /toxicidad
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