Pigeons (Columba livia) are a suitable experimental model for Neospora caninum infection in birds

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Experimental infection of Newcastle disease virus in pigeons (Columba livia): Humoral antibody response, contact transmission and viral genome shedding

The aim of this study was to evaluate the humoral antibody response, the genome viral excretion and the contact transmission of pathogenic chicken origin Newcastle disease virus (NDV) from experimentally infected pigeons (Columba livia) to in-contact pigeon. The antibody response to infection was assessed by the hemagglutination inhibition (HI) test and the genome viral excretion was detected by RT-PCR. Viral strain induced high antibody levels, both in inoculated and in sentinel birds. The pathogenic viral strain for chickens was unable to produce clinical signs of the disease in experimentally infected pigeons, although it induced the Immoral antibody response and produced NDV genome shedding. NDV genome was detected intermittently throughout the experimental period, from 5 days post-infection (dpi) to 24 dpi. Therefore, viral genome shedding occurred for 20 days. The viral genome was detected in all birds, between I I and 13 dpi. Furthermore, the high infectivity of the virus was confirmed, as all non-inoculated sentinel pigeons showed antibody levels as high as those of inoculated birds. (C) 2007 Elsevier B.V. All rights reserved.

PREVALENCE of SALMONELLA SPP. ANTIBODIES TO TOXOPLASMA GONDII, and NEWCASTLE DISEASE VIRUS IN FERAL PIGEONS (COLUMBA LIVIA) IN THE CITY of JABOTICABAL, BRAZIL

The rock pigeon (Columba livia) may serve as a reservoir for several pathogenic agents that can be transmitted to poultry, wildlife, domesticated pets, and/or humans via excreta, secretions, or dust from feathers. In addition, ingestion of infected pigeons by wild and domestic animals can also transmit these pathogenic agents. The health status of 126 free-living pigeons in an urban area was evaluated by microbiologic culture for Salmonella and serologic testing for the presence of antibodies for Toxoplasma gondii and for Newcastle disease virus (NDV) from 120 and 109 pigeons, respectively. After drawing blood, the birds were euthanized, and fragments of the liver, spleen, lungs, and gonads, and feces were cultured for Salmonella spp. Salmonella spp. was isolated from 10 birds (7.94%), of which 8 were Salmonella typhimurium, one was Salmonella enterica subsp. enterica serotype 4,12 and one was Salmonella enterica subsp. enterica serotype 4,12,i. Six of 109 pigeons (5.50%) were positive for NDV antibodies when using the hemagglutination inhibition test. Toxoplasma gondii antibodies were detected by immunofluorescence in one of 120 sera tested (0.83%). The results indicate that feral rock pigeons were exposed to NDV and T gondii, although the exposure was low. In addition, these birds had Salmonella spp. and could disseminate this pathogen in the environment.

Chlamydophila psittaci and Toxoplasma gondii infection in pigeons (Columba livia) from São Paulo State, Brazil

Pigeons (Columba livia) cohabit with humans in urban and rural areas, representing a public health problem since microorganisms are transmitted through the inhalation of dust from their dry feces (chlamydiosis) and through ingestion of their undercooked or poorly refrigerated meat (toxoplasmosis). This study aimed to evaluate the presence of Chlamydophila psittaci and Toxoplasma gondii in pigeons from four cities in São Paulo State, Brazil. C psittaci was evaluated through hemi-nested polymerase chain reaction (hnPCR) using cloacal and tracheal swabs, whereas T. gondii specific antibodies were assessed by means of modified agglutination test (MAT), mouse brain and muscle bioassay, and polymerase chain reaction (PCR). To confirm the infection in mice, T. gondii antibodies were assayed by using indirect fluorescent antibody test (IFAT). Considering C. psittaci, 40/238 (16.8%; 95%CI 12.6-22.1%) samples were positive according to hnPCR, especially for the cities of São Paulo (42.5%) and Bauru (35%). As regards T. gondii, 12/238 (5%; 95%CI 2.9-8.6%) serum samples were positive according to MAT. of these, five samples had titer equal to 1:8; six samples, 1:16; and one sample, 1:32. Bioassay, IFAT and PCR were negative for mouse toxoplasmosis. The absence of T. gondii antibodies suggests that pigeons may be infected with a low concentration of the agent, not detected by the antigen test. Thus, C. psittaci represents an actual problem concerning bird health. (C) 2010 Elsevier B.V. All rights reserved.

PRP8 intein in Ajellomycetaceae family pathogens: Sequence analysis, splicing evaluation and homing endonuclease activity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic structure of the migratory catfish Pseudoplatystoma corruscans (Siluriformes: Pimelodidae) suggests homing behaviour

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

CHOLECYSTOKININ-LIKE IMMUNOREACTIVE RETINAL GANGLION-CELLS PROJECT TO THE VENTRAL LATERAL GENICULATE-NUCLEUS IN PIGEONS

A subpopulation of retinal ganglion cells projecting to the pigeon ventral lateral geniculate nucleus was shown to contain cholecystokinin-like immunoreactivity. These ganglion cells were mainly distributed in the peripheral retina, and their somata sizes were medium to large (14-23-mu-m). Taken together with previous findings, these results indicate that the retinal input to the ventral geniculate is chemically heterogeneous.

EFFECTS OF MASSIVE TELENCEPHALIC LESIONS ON THE ORGANIZATION OF BEHAVIOR IN PIGEONS (COLUMBA-LIVIA)

The effects of massive lesions of the telencephalon on the behavioral repertoire of captive pigeons were investigated. The behavior of four birds with an intact telencephalon was compared to that of four birds submitted to ablation of telencephalic structures. Behavioral audio recording was done according to previously defined categories in three daily sessions for fifteen days. Experimental birds were followed up for one month. Immediately after the lesion, operated birds showed decreases in the occurrence of different behaviors such as coordinated movements, feeding, interaction, preening, maintenance, exploration and vocalization and increases in locomotion and discrete movements of the body when compared to the control birds (P < 0.05). Recovery of exploration (P < 0.05), feeding and localization was observed during the follow-up period. These data are interpreted as suggestive of a functional role of the telencephalon in the organization of behavior and a long-term recovery of behavior after detelencephalation.

A liquid-phase-blocking concanavalin A enzyme-linked immunosorbent assay for the detection of antibodies against Newcastle disease virus in serum of free-ranging pigeons

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

ASSOCIATIVE SYMMETRY BY PIGEONS AFTER FEW-EXEMPLAR TRAINING

The present experiment investigated whether pigeons can show associative symmetry on a two-alternative matching to-sample procedure The procedure consisted of a within subject sequence of training and testing with reinforcement and It provided (a) exemplars of symmetrical responding and (b) all prerequisite discriminations among test samples and comparisons After pigeons had learned two arbitrary matching tasks (A B and C D) they were given a reinforced symmetry test for half of the baseline relations (B1-A1 and D1-C1) To control for the effects of reinforcement during testing two novel nonsymmetrical responses were concurrently reinforced using the other baseline stimuli (D2-A2 and B2-C2) Pigeons matched at chance on both types of relations thus indicating no evidence for symmetry These symmetrical and nonsymmetrical relations were then directly trained in order to provide exemplars of symmetry and all prerequisite discriminations for a second test The symmetrical test relations were now B2-A2 and D2-C2 and the nonsymmetrical relations were D1-A1 and B1-C1 On this test 1 pigeon showed clear evidence of symmetry 2 pigeons showed weak evidence and 1 pigeon showed no evidence The previous training of all prerequisite discriminations among stimuli and the within subject control for testing with reinforcement seem to have set favorable conditions for the emergence of symmetry in nonhumans However the variability across subjects shows that methodological variables still remain to be controlled

Daily cycling of nitric oxide synthase (NOS) in the hippocampus of pigeons (C. livia)

Abstract: Background: Nitric oxide synthase (NOS) is essential for the synthesis of nitric oxide (NO), a non-conventional neurotransmitter with an important role in synaptic plasticity underlying processes of hippocampus-dependent memory and in the regulation of biological clocks and circadian rhythms. Many studies have shown that both the NOS cytosolic protein content and its enzymatic activity present a circadian variation in different regions of the rodent brain, including the hippocampus. The present study investigated the daily variation of NOS enzymatic activity and the cytosolic content of nNOS in the hippocampus of pigeons. Results: Adult pigeons kept under a skeleton photoperiod were assigned to six different groups. Homogenates of the hippocampus obtained at six different times-of-day were used for NOS analyses. Both iNOS activity and nNOS cytosolic protein concentrations were highest during the subjective light phase and lowest in the subjective dark phase of the circadian period. ANOVA showed significant time differences for iNOS enzymatic activity (p < 0.05) and for nNOS protein content (p < 0.05) in the hippocampus. A significant daily rhythm for both iNOS and nNOS was confirmed by analysis with the Cosinor method (p < 0.05). The present findings indicate that the enzymatic activity of iNOS and content of nNOS protein in the hippocampus of pigeons exhibit a daily rhythm, with acrophase values occurring during the behavioral activity phase. Conclusions: The data corroborate the reports on circadian variation of NOS in the mammalian hippocampus and can be considered indicative of a dynamic interaction between hippocampus-dependent processes and circadian clock mechanisms.

Daily cycling of nitric oxide synthase (NOS) in the hippocampus of pigeons (C. livia)

Background: Nitric oxide synthase (NOS) is essential for the synthesis of nitric oxide (NO), a non-conventional neurotransmitter with an important role in synaptic plasticity underlying processes of hippocampus-dependent memory and in the regulation of biological clocks and circadian rhythms. Many studies have shown that both the NOS cytosolic protein content and its enzymatic activity present a circadian variation in different regions of the rodent brain, including the hippocampus. The present study investigated the daily variation of NOS enzymatic activity and the cytosolic content of nNOS in the hippocampus of pigeons. Results: Adult pigeons kept under a skeleton photoperiod were assigned to six different groups. Homogenates of the hippocampus obtained at six different times-of-day were used for NOS analyses. Both iNOS activity and nNOS cytosolic protein concentrations were highest during the subjective light phase and lowest in the subjective dark phase of the circadian period. ANOVA showed significant time differences for iNOS enzymatic activity (p < 0.05) and for nNOS protein content (p < 0.05) in the hippocampus. A significant daily rhythm for both iNOS and nNOS was confirmed by analysis with the Cosinor method (p < 0.05). The present findings indicate that the enzymatic activity of iNOS and content of nNOS protein in the hippocampus of pigeons exhibit a daily rhythm, with acrophase values occurring during the behavioral activity phase. Conclusions: The data corroborate the reports on circadian variation of NOS in the mammalian hippocampus and can be considered indicative of a dynamic interaction between hippocampus-dependent processes and circadian clock mechanisms.

Group I Introns and Homing Endonucleases in T-even-like Bacteriophages

Homing endonucleases are rare-cutting enzymes that cleave DNA at a site near their own location, preferentially in alleles lacking the homing endonuclease gene (HEG). By cleaving HEG-less alleles the homing endonuclease can mediate the transfer of its own gene to the cleaved site via a process called homing, involving double strand break repair. Via homing, HEGs are efficiently transferred into new genomes when horizontal exchange of DNA occurs between organisms. Group I introns are intervening sequences that can catalyse their own excision from the unprocessed transcript without the need of any proteins. They are widespread, occurring both in eukaryotes and prokaryotes and in their viruses. Many group I introns encode a HEG within them that confers mobility also to the intron and mediates the combined transfer of the intron/HEG to intronless alleles via homing. Bacteriophage T4 contains three such group I introns and at least 12 freestanding HEGs in its genome. The majority of phages besides T4 do not contain any introns, and freestanding HEGs are also scarcely represented among other phages. In the first paper we looked into why group I introns are so rare in phages related to T4 in spite of the fact that they can spread between phages via homing. We have identified the first phage besides T4 that contains all three T-even introns and also shown that homing of at least one of the introns has occurred recently between some of the phages in Nature. We also show that intron homing can be highly efficient between related phages if two phages infect the same bacterium but that there also exists counteracting mechanisms that can restrict the spread of introns between phages. In the second paper we have looked at how the presence of introns can affect gene expression in the phage. We find that the efficiency of splicing can be affected by variation of translation of the upstream exon for all three introns in T4. Furthermore, we find that splicing is also compromised upon infection of stationary-phase bacteria. This is the first time that the efficiency of self-splicing of group I introns has been coupled to environmental conditions and the potential effect of this on phage viability is discussed. In the third paper we have characterised two novel freestanding homing endonucleases that in some T-even-like phages replace two of the putative HEGs in T4. We also present a new theory on why it is a selective advantage for freestanding, phage homing endonucleases to cleave both HEG-containing and HEG-less genomes.