Assessment of Cholinesterase inhibition activity of birds inhabiting pesticide exposed croplands and protected area in hot semi-arid region of Pakistan / Avaliação da atividade de inibição da colinesterase de pássaros que habitam áreas cultivadas e áreas protegidas expostas a pesticidas na região semiárida quente do Paquistão

Abstract Acetylcholinesterase (AChE) activity levels can be used as an indicator for AChE inhibition due to pesticide poisoning in bird species. We assessed the comparative brain cholinesterase (AChE) activity level of five bird species inhabiting pesticide exposed croplands and Protected Area i.e. Deva Vatala National Park (DVNP), Bhimber by using a spectrophotometric method. AChE activity levels ranged from 56.3 to 85.9 µmol/min/g of brain tissue of birds representing DVNP. However, AChE activity levels ranged from 27.6 to 79.9 µmol/min/g of brain tissue of birds representing croplands. AChE activity levels observed in Jungle babbler, Common babbler, and Red-vented bulbul showed significant differences (P < 0.05) at two sites. However, White wagtail and Black drongo demonstrated non-significant differences (P > 0.05). Maximum inhibition was recorded in Jungle babbler (53%) followed by Common babbler (35%), Red-vented bulbul (18%), White wagtail (15%), and Black drongo (7%). The brain cholinesterase inhibition levels under-protected ecosystems (DVNP, Bhimber) and agricultural landscape suggest insecticidal contamination and its impact on avifauna diversity. The study also emphasizes on the importance of pesticide-free zones to protect the biodiversity of birds.

Resumo Os níveis de atividade da acetilcolinesterase (AChE) podem ser usados ​​como um indicador para a inibição da AChE devido ao envenenamento por pesticidas em espécies de aves. Avaliamos o nível de atividade comparativa da colinesterase cerebral (AChE) de cinco espécies de aves que habitam áreas cultivadas expostas a pesticidas e Área Protegida, ou seja, Deva Vatala National Park (DVNP), Bhimber, usando um método espectrofotométrico. Os níveis de atividade da AChE variaram de 56,3 a 85,9 µmol / min / g de tecido cerebral de aves representando DVNP. No entanto, os níveis de atividade da AChE variaram de 27,6 a 79,9 µmol / min / g de tecido cerebral de aves representando áreas de cultivo. Os níveis de atividade de AChE observados no tagarela da selva, tagarela comum e bulbul vermelho exalado mostraram diferenças significativas (P < 0,05) em dois locais. No entanto, alvéola branca e drongo preto demonstraram diferenças não significativas (P > 0,05). A inibição máxima foi registrada no tagarela da selva (53%), seguido pelo tagarela comum (35%), bulbul vermelho (18%), alvéola branca (15%) e drongo preto (7%). Os níveis de inibição da colinesterase cerebral nos ecossistemas subprotegidos (DVNP, Bhimber) e na paisagem agrícola sugerem contaminação por inseticida e seu impacto na diversidade da avifauna. O estudo também enfatiza a importância das zonas livres de pesticidas para proteger a biodiversidade das aves.

Enzymatic and biochemical characterization of Bungarus sindanus snake venom acetylcholinesterase

This study analyses venom from the elapid krait snake Bungarus sindanus, which contains a high level of acetylcholinesterase (AChE) activity. The enzyme showed optimum activity at alkaline pH (8.5) and 45ºC. Krait venom AChE was inhibited by substrate. Inhibition was significantly reduced by using a high ionic strength buffer; low ionic strength buffer (10 mM PO4 pH 7.5) inhibited the enzyme by 1. 5mM AcSCh, while high ionic strength buffer (62 mM PO4 pH 7.5) inhibited it by 1 mM AcSCh. Venom acetylcholinesterase was also found to be thermally stable at 45ºC; it only lost 5% of its activity after incubation at 45ºC for 40 minutes. The Michaelis-Menten constant (Km) for acetylthiocholine iodide hydrolysis was found to be 0.068 mM. Krait venom acetylcholinesterase was also inhibited by ZnCl2, CdCl2, and HgCl2 in a concentrationdependent manner. Due to the elevated levels of AChE with high catalytic activity and because it is more stable than any other sources, Bungarus sindanus venom is highly valuable for biochemical studies of this enzyme.(AU)

Intoxicação por organofosforados em bezerros no Uruguai / Organophosphate poisoning in Calves in Uruguay

Background: Organophosphate compounds are used worldwide in animal agriculture as pesticides, inseticides and herbicides. The inappropriate use of these anticholinesterasic agents may cause poisoning, apart of great economic losses. Organophosphate poisoning may affect all animal species. Organophosphate overdose induce increase in tissue acetylcholine content and, therefore, enhanced parasympathetic and post-ganglionic sympathetic nerve activities. The toxic effects are shown as muscarinic, nicotinic and central nervous system signs. The muscarinic signs are characterized by increased peristaltism, salivation, lacrimation, nasal discharge, bronchial constrition, miosis and sudoresis, among others. The nicotinic signs are mainly locomotor signs and include muscular tremors, weakness, and flaccid paralysis. The effects on the central nervous system include inquietation, ataxia, convulsions, depression and coma. Minimal differences may be seen in the diseases caused by different compounds; nevertheless, the route of administration may facilitate the exacerbation of some signs instead of others. Case: This paper report an outbreak of organophosphate poisoning in calves. The disease occurred in a dairy farm located in Florida, Uruguay and affected female Holstein 15-day-old calves. The main owner complaints were apathy, standing difficulty and sialorrhea. Seven out of twenty calves presented neurological signs such as incoordination and sternal recumbency. The clinical examination revealed prostration, lacrimation, tongue protusion, muscular weakness and miosis. At anamnesis, the previous application, in the day before, of a pour-on inseticide was noticed. The composition of the commercial product was ethion (15%), which is an insecticide organophosphate widely used as an antiparasitic drug. Affected animals were treated with intravenous atropine sulfate 1% (0.50 mg/kg) and sodium chloride 0.9%. Atropine sulfate is a potent parasympatholytic agent that inhibits the effects of acetylcholine at the postganglionic parasympathetic neuroeffector junctions. Ten minutes after the treatment, most calves showed an improvement in health status. Only one calf needed two extra doses at 1-hour intervals to recuperate. The presumptive diagnosis was based on the clinical findings and supported by depressed blood cholinesterase level. Discussion: The rapid therapeutic response of affected animals to specific treatment also supports the hypothesis. The outcome of this outbreak relies in the aggressive approach of the team and adequate treatment choice. In spite of other differential diagnosis possibilities such as poisoning by carbamate and pyrethroid, the clinical findings, laboratory result and therapeutic response allowed us to attribute this outbreak to the misuse of organophosphate. The key to an excellent outcome, when dealing with organophosphate poisoning, is immediate treatment.

Intoxicação por organofosforados em bezerros no Uruguai / Organophosphate poisoning in Calves in Uruguay

Background: Organophosphate compounds are used worldwide in animal agriculture as pesticides, inseticides and herbicides. The inappropriate use of these anticholinesterasic agents may cause poisoning, apart of great economic losses. Organophosphate poisoning may affect all animal species. Organophosphate overdose induce increase in tissue acetylcholine content and, therefore, enhanced parasympathetic and post-ganglionic sympathetic nerve activities. The toxic effects are shown as muscarinic, nicotinic and central nervous system signs. The muscarinic signs are characterized by increased peristaltism, salivation, lacrimation, nasal discharge, bronchial constrition, miosis and sudoresis, among others. The nicotinic signs are mainly locomotor signs and include muscular tremors, weakness, and flaccid paralysis. The effects on the central nervous system include inquietation, ataxia, convulsions, depression and coma. Minimal differences may be seen in the diseases caused by different compounds; nevertheless, the route of administration may facilitate the exacerbation of some signs instead of others. Case: This paper report an outbreak of organophosphate poisoning in calves. The disease occurred in a dairy farm located in Florida, Uruguay and affected female Holstein 15-day-old calves. The main owner complaints were apathy, standing difficulty and sialorrhea. Seven out of twenty calves presented neurological signs such as incoordination and sternal recumbency. The clinical examination revealed prostration, lacrimation, tongue protusion, muscular weakness and miosis. At anamnesis, the previous application, in the day before, of a pour-on inseticide was noticed. The composition of the commercial product was ethion (15%), which is an insecticide organophosphate widely used as an antiparasitic drug. Affected animals were treated with intravenous atropine sulfate 1% (0.50 mg/kg) and sodium chloride 0.9%. Atropine sulfate is a potent parasympatholytic agent that inhibits the effects of acetylcholine at the postganglionic parasympathetic neuroeffector junctions. Ten minutes after the treatment, most calves showed an improvement in health status. Only one calf needed two extra doses at 1-hour intervals to recuperate. The presumptive diagnosis was based on the clinical findings and supported by depressed blood cholinesterase level. Discussion: The rapid therapeutic response of affected animals to specific treatment also supports the hypothesis. The outcome of this outbreak relies in the aggressive approach of the team and adequate treatment choice. In spite of other differential diagnosis possibilities such as poisoning by carbamate and pyrethroid, the clinical findings, laboratory result and therapeutic response allowed us to attribute this outbreak to the misuse of organophosphate. The key to an excellent outcome, when dealing with organophosphate poisoning, is immediate treatment.(AU)