RESUMO
Fusarium species and fumonisin production by toxigenic strains were investigated. During 1996-1998, 158 samples of poultry feeds were collected from a factory located in the department of Rio Cuarto Córdoba province, Argentina. The most common species of Fusarium were F. moniliforme (60.7%) and F. nygamai (35.4%) followed by F. semitectum, F. subglutinans, F. proliferatum, F. dlamini, F. solani, F. oxysporum and F. napiforme. Fungal counts ranged from 1 x 10(3) to 8 x 10(5) CFU/g with mean values from 1.5 x 10(3) to 2.3 x 10(5) CFU/g. The highest counts were for F. dlamini, F. subglutinans, F. moniliforme and F. nygamai. Strains of F. moniliforme, F. nygamai, and E. proliferatum were screened for their potential to produce fumonisin B1 (FB1), fumonisin B2 (FB2) and fumonisin B3 (FB3) in corn grain. The samples were analysed using a modified high performance liquid chromatography method. The strains assayed, 43 strains, produced three fumonisins. There was a high degree of variability in the quantities of FB1, FB2, and FB3 produced. The toxin produced in highest levels by the majority of the strains was FB1. The range of concentration varied from 5.4 to 3,991, 1.01 to 189 and 0.4 to 765 ppm per gram of corn for FB1, FB2 and FB3 respectively. The toxigenic pattern of strains was normal, although two strains of F. moniliforme produced exceptionally high concentrations of FB3 and minor concentrations of FB2 and FB1. This is the first report from Argentina on Fusarium species in poultry feeds and fumonisin production by these strains.
Assuntos
Ração Animal/microbiologia , Fusarium/isolamento & purificação , Fusarium/metabolismo , Micotoxinas/biossíntese , Animais , Argentina , Contagem de Colônia Microbiana , Fusarium/classificação , Aves DomésticasRESUMO
A total of 180 samples of poultry feeds were collected during 1996 and 1997 from different factories in the south of the province of Córdoba-Argentina. They were examined for the occurrence of Penicillium spp. and Aspergillus group species. Likewise, the capacity to produce aflatoxins by the Aspergillus section flavi group was determined. The predominant species of Aspergillus were A. flavus and A. parasiticus. For Penicillium spp., P. brevicompactum, P. purpurogenum and P. oxalicum were identified. Less frequently isolated were A. candidus, A. fumigatus, A. niger, A. orizae, A. parvulus, A. tamarii, A. terreus, and P. expansum, P. funiculosum, P. minioluteum, P. pinophylum, P. restrictum, P. variable and others. The mean value counts ranged from 1 x 10(3) to 9.5 x 10(4) CFU/g for the Aspergillus spp. and from 1.2 x 10(3) to 2.5 x 10(5) CFU/g for the Penicillium spp. When cultured on autoclaved rice kernels for 1 week in the dark at 25 degrees C, mycotoxin production by strains of A. flavus was as follows: 21 of the 45 assayed strains (47%) produced aflatoxins. From them, 24% of the isolates produced AFB1 and AFB2 with levels from 181 to 14545 and 6 to 3640 micrograms/kg respectively. Only 10 strains produced AFB1 with levels from 10 to 920 micrograms/kg. Fifty percent of the A. parasiticus strain was toxicogenic; six aflatoxicogenic profiles were identified. Only 10% of the strains produced all of the aflatoxins. These results showed that a potential exists for the production of mycotoxins by the Aspergillus section flavi and the Penicillium spp. They also suggested an association of mycotoxicosis with poultry feeds in Argentina.
Assuntos
Ração Animal/microbiologia , Aspergillus/isolamento & purificação , Penicillium/isolamento & purificação , Aflatoxinas/análise , Animais , Argentina , Aspergillus/classificação , Microbiologia de Alimentos , Técnicas de Tipagem Micológica , Penicillium/classificação , Aves DomésticasRESUMO
Antidepressants exert mixed actions on serotonergic and catecholaminergic systems. However, it is unknown whether a catecholaminergic blockade impinge on the actions of a tricyclic with serotonergic agonist properties (clomipramine) in limbic structures. The aim of the present study is to explore the effects of a catecholaminergic lesion in the basolateral amygdala on the firing rate of lateral septal, and hippocampal neurons in rats treated with clomipramine. An amygdaline lesion with 6-OHDA resembled the actions of clomipramine on the firing rate in lateral septal neurons, i.e. an increased rate of firing. However, the lesion blocked further effects of clomipramine on septal firing. Clomipramine decreased the firing rate in hippocampal neurons; however, neither the 6-OHDA lesion nor the added treatment with clomipramine modified the firing rate. It is concluded that an intact catecholaminergic amygdaloid input to lateral septal nuclei is necessary for clomipramine actions; however, the initial action of the tricyclic may involve a catecholaminergic blockade.
Assuntos
Tonsila do Cerebelo/efeitos dos fármacos , Clomipramina/farmacologia , Hipocampo/fisiologia , Receptores Adrenérgicos alfa/fisiologia , Receptores de Serotonina/fisiologia , Septo Pelúcido/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Hipocampo/efeitos dos fármacos , Masculino , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Oxidopamina/toxicidade , Ratos , Ratos Wistar , Receptores Adrenérgicos alfa/efeitos dos fármacos , Receptores de Serotonina/efeitos dos fármacos , Septo Pelúcido/citologia , Septo Pelúcido/efeitos dos fármacosRESUMO
In the rat, long-term clomipramine increases the firing rate in lateral septal neurons. Although the hippocampus is the main afference for septal nuclei, it is unknown whether clomipramine increases the firing rate in most of hippocampal-septal neurons. Therefore, the present study explored the actions of long-term clomipramine in lateral septal neurons identified by their relation to the hippocampus. In most recordings, hippocampal stimulation produced a brief excitatory short-latency response, followed by a period of inhibition of firing. These neurons increased their firing rate after clomipramine treatment. Other septal neurons not respondent to hippocampal stimulation did not respond to clomipramine treatment, either. We concluded that only hippocampal-septal neurons are clomipramine responders too, and the drug-induced enhancement of firing rate is likely to be mediated by an interneuron-mediated disinhibition process.
Assuntos
Clomipramina/farmacologia , Hipocampo/fisiologia , Neurônios/efeitos dos fármacos , Núcleos Septais/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Animais , Clomipramina/administração & dosagem , Estimulação Elétrica , Masculino , Neurônios/fisiologia , Ratos , Ratos Wistar , Núcleos Septais/citologia , Estimulação QuímicaRESUMO
An increased firing rate in lateral septal nuclei (LSN) appears in urethane-anesthetized rats after several acute drug and non-drug human antidepressant treatments. A still more pronounced increase in firing rate is produced in LSN after clomipramine (CMI) long-term treatment. In spite of urethane is a widely used anesthetic for single unit extracellular recordings, it modifies evoked potentials wave-form. Therefore, present study discards urethane interaction with CMI in LSN single unit extracellular recordings. CMI was acutely injected (1.25 mg/kg: IP) either to urethane-anesthetized, or non-anesthetized encephale-isolé rats. The CMI treated groups showed higher rates of firing in LSN regardless of the use of general anesthesia during recordings. Another group of urethane-anesthetized rats received intracerebroventricular (ICV) microinjections of CMI (100 micrograms/10 microliters/1 min). An amount of 42.8% of LSN-recorded neurons responded with a long-lasting increased firing rate. Results discard urethane and CMI interactions. Additionally, systemic actions of CMI on firing rate of LSN are reproduced by ICV/route microinjections.