RESUMO
Location and degree of protection of aerial buds are important functional traits in disturbance- or stress-prone environments since aerial buds ensure the development of new organs under favourable growing conditions. This study was carried out in a Brazilian Cerrado area under regeneration after long-term Pinus cultivation, where the trees were clear-cut in 2012 and the remaining material was burned in 2014. After the fire treatment, several species resprouted from belowground organs and their aboveground organs were directly exposed to full sunlight. We collected 15 terminal branches with fully expanded leaves from three individuals of each of three Eugenia species to investigate if those with well-developed belowground organs invest in bark for aboveground bud protection. The samples were analysed using light and electron microscopy. In addition to terminal and axillary buds, all species presented accessory buds, and the number varied according to the node analysed. None of the aerial buds were protected by bark, but all were well protected by cataphylls and densely pubescent leaf primordia. There were also inter- and intra-petiolar colleters that released a mucilaginous protein exudate. The distance between the shoot apical meristem and the outer surface was longer in the terminal bud than in axillary buds. The bud leaf primordia covering the shoot apical meristem had a thick cuticle, unicellular non-glandular trichomes that accumulate phenolic and lipophilic compounds, and secretory cavities. Our study shows that all three Eugenia species studied here had highly protected aerial buds allocated from belowground organs. These morphological traits may improve the chances of the species' persistence in areas subjected to frost events, low relative humidity, high irradiance and harmful UV levels.
Assuntos
Eugenia , Incêndios , Meristema , Árvores , Folhas de Planta/metabolismoRESUMO
The Brazilian poultry industry is an outstanding national and international agribusiness sector. Among the Brazilian states, São Paulo is the largest producer of commercial eggs and the fourth largest producer and exporter of chicken meat. Alternatively, semi-intensive and/or organic poultry production have also obtained a significant share of the domestic market as a result of consumer demand. Helminths affect the performance of the birds, causing significant direct or indirect losses. The objective of the present study was to identify the main helminth species present in chickens reared in 17 municipalities of the state of São Paulo. In total, 359 adult birds were investigated. The birds were reared in different housing systems and were obtained from 69 farms in the selected regions. The birds were submitted to procedures for the detection and identification of helminth parasites, following international standards. The evaluation of the small intestine employed the Mello-Campos method (Mello & Campos, 1974), which allows better recovery of cestode scolices attached to the intestinal mucosa. Stereomicroscopy was used to evaluate the collected materials, and light microscopy was used to identify the species based on their morphological characteristics. The following helminth species were diagnosed in chickens reared in 17 municipalities of the state of São Paulo: nematodes (Ascaridia galli, Capillaria sp., Cheilospirura hamulosa, Heterakis gallinarum, Oxyspirura mansoni, and Strongyloides sp.), cestodes (Amoebotaenia cuneata, Choanotaenia infundibulum, Hymenolepis sp., Raillietina cesticillus, Raillietina echinobothrida, and Raillietina tetragona), and trematodes (Zygocotyle lunata and Postharmostomum commutatum).
Assuntos
Animais , Carne/análise , Galinhas/anormalidades , Galinhas/parasitologia , Helmintos/crescimento & desenvolvimento , Ascaridia , Capillaria , StrongyloideaRESUMO
The Brazilian poultry industry is an outstanding national and international agribusiness sector. Among the Brazilian states, São Paulo is the largest producer of commercial eggs and the fourth largest producer and exporter of chicken meat. Alternatively, semi-intensive and/or organic poultry production have also obtained a significant share of the domestic market as a result of consumer demand. Helminths affect the performance of the birds, causing significant direct or indirect losses. The objective of the present study was to identify the main helminth species present in chickens reared in 17 municipalities of the state of São Paulo. In total, 359 adult birds were investigated. The birds were reared in different housing systems and were obtained from 69 farms in the selected regions. The birds were submitted to procedures for the detection and identification of helminth parasites, following international standards. The evaluation of the small intestine employed the Mello-Campos method (Mello & Campos, 1974), which allows better recovery of cestode scolices attached to the intestinal mucosa. Stereomicroscopy was used to evaluate the collected materials, and light microscopy was used to identify the species based on their morphological characteristics. The following helminth species were diagnosed in chickens reared in 17 municipalities of the state of São Paulo: nematodes (Ascaridia galli, Capillaria sp., Cheilospirura hamulosa, Heterakis gallinarum, Oxyspirura mansoni, and Strongyloides sp.), cestodes (Amoebotaenia cuneata, Choanotaenia infundibulum, Hymenolepis sp., Raillietina cesticillus, Raillietina echinobothrida, and Raillietina tetragona), and trematodes (Zygocotyle lunata and Postharmostomum commutatum).(AU)
Assuntos
Animais , Galinhas/anormalidades , Galinhas/parasitologia , Helmintos/crescimento & desenvolvimento , Carne/análise , Ascaridia , Capillaria , StrongyloidesRESUMO
It has been proposed that spontaneous panic attacks are the outcome of the misfiring of an evolved suffocation alarm system. Evidence gathered in the last years is suggestive that the dorsal periaqueductal gray (dPAG) in the midbrain harbors a hypoxia-sensitive suffocation alarm system. We here investigated whether facilitation of 5-HT-mediated neurotransmission within the dPAG changes panic-like defensive reactions expressed by male Wistar rats submitted to a hypoxia challenge (7% O2), as observed in other animal models of panic. Intra-dPAG injection of 5-HT (20 nmol), (±)-8-hydroxy-2-(di-n-propylamino) tetralin hydrobromide (8-OH-DPAT) (8 nmol), a 5-HT1A receptor agonist, or (±)-2,5-dimethoxy-4-iodo amphetamine hydrochloride (DOI) (16 nmol), a preferential 5-HT2A agonist, reduced the number of upward jumps directed to the border of the experimental chamber during hypoxia, interpreted as escape attempts, without affecting the rats' locomotion. These effects were similar to those caused by chronic, but not acute, intraperitoneal administration of the antidepressant fluoxetine (5-15 mg/kg), or acute systemic administration of the benzodiazepine receptor agonist alprazolam (1-4 mg/kg), both drugs clinically used in the treatment of panic disorder. Our findings strengthen the view that the dPAG is a key encephalic area involved in the defensive behaviors triggered by activation of the suffocation alarm system. They also support the use of hypoxia-evoked escape as a model of respiratory-type panic attacks.
Assuntos
Mecanismos de Defesa , Hipóxia/complicações , Hipóxia/patologia , Pânico/fisiologia , Substância Cinzenta Periaquedutal/metabolismo , Serotonina/metabolismo , Alprazolam/farmacologia , Análise de Variância , Animais , Relação Dose-Resposta a Droga , Moduladores GABAérgicos/farmacologia , Masculino , Microinjeções , Substância Cinzenta Periaquedutal/efeitos dos fármacos , Ratos , Ratos Wistar , Serotoninérgicos/farmacologiaRESUMO
AIM: Hydrogen sulphide (H2S) is endogenously produced and plays an important role as a modulator of neuronal functions; however, its modulatory role in the central CO2 chemoreception is unknown. The aim of the present study was to assess the role of endogenously produced H2S in the ventilatory response to hypercapnia in adult conscious rats. METHODS: Cystathionine ß-synthase (CBS) and cystathionine γ-lyase (CSE) inhibitors (aminooxyacetate: AOA and propargylglycine: PAG respectively) and a H2S donor (sodium sulphide: Na2S) were microinjected into the fourth ventricle (4V). Ventilation (VÌ(E)), oxygen consumption (VÌO2) and body temperature were recorded before (room air) and during a 30-min CO2 exposure (hypercapnia, 7% CO2). Endogenous H2S levels were measured in the nucleus tractus solitarius (NTS). RESULTS: Microinjection of Na2S (H2S donor), AOA (CBS inhibitor) or PAG (CSE inhibitor) did not affect baseline of the measured variables compared to control group (vehicle). In all experimental groups, hypercapnia elicited an increase in VÌ(E). However, AOA microinjection, but not PAG, attenuated the ventilatory response to hypercapnia (P < 0.05), whereas Na2S elicited a slight, not significant, enhancement. Moreover, endogenous H2S levels were found higher in the NTS after hypercapnia (P < 0.05) compared to room air (normoxia) condition. CONCLUSION: There are a few reports on the role of gaseous transmitters in the control of breathing. Importantly, the present data suggest that endogenous H2S via the CBS-H2S pathway mediates the ventilatory response to hypercapnia playing an excitatory role.
Assuntos
Sulfeto de Hidrogênio/farmacologia , Hipercapnia/tratamento farmacológico , Envelhecimento/metabolismo , Ácido Amino-Oxiacético/metabolismo , Animais , Cistationina beta-Sintase/metabolismo , Cistationina gama-Liase/metabolismo , Modelos Animais de Doenças , Sulfeto de Hidrogênio/metabolismo , Hipercapnia/metabolismo , Masculino , Ratos Wistar , Sulfetos/farmacologiaRESUMO
AIM: We hypothesized that hydrogen sulphide (H2 S), acting specifically in the anteroventral preoptic region (AVPO - an important integrating site of thermal and cardiorespiratory responses to hypoxia in which H2 S synthesis has been shown to be increased under hypoxic conditions), modulates the hypoxic ventilatory response. METHODS: To test this hypothesis, we measured pulmonary ventilation (VËE) and deep body temperature of rats before and after intracerebroventricular (icv) or intra-AVPO microinjection of aminooxyacetate (AOA; CBS inhibitor) or Na2 S (H2 S donor) followed by 60 min of hypoxia exposure (7% O2 ). Furthermore, we assessed the AVPO levels of H2 S of rats exposed to hypoxia. Control rats were kept under normoxia. RESULTS: Microinjection of vehicle, AOA or Na2 S did not change VËE under normoxic conditions. Hypoxia caused an increase in ventilation, which was potentiated by microinjection of AOA because of a further augmented tidal volume. Conversely, treatment with Na2 S significantly attenuated this response. The in vivo H2 S data indicated that during hypoxia the lower the deep body temperature the smaller the degree of hyperventilation. Under hypoxia, H2 S production was found to be increased in the AVPO, indicating that its production is responsive to hypoxia. The CBS inhibitor attenuated the hypoxia-induced increase in the H2 S synthesis, suggesting an endogenous synthesis of the gas. CONCLUSION: These data provide solid evidence that AVPO H2 S production is stimulated by hypoxia, and this gaseous messenger exerts an inhibitory modulation of the hypoxic ventilatory response. It is probable that the H2 S modulation of hypoxia-induced hyperventilation is at least in part in proportion to metabolism.