Redox profile of silver catfish challenged with Aeromonas hydrophila and treated with hexane extract of Hesperozygis ringens (Benth.) Epling through immersion bath.

The growing increase in the fish farming sector has favored the establishment of bacterial outbreaks caused by Aeromonas hydrophila in several species. The hexane extract of Hesperozygis ringens (HEHR) (Lamiaceae) leaves increased the survival rate of silver catfish (Rhamdia quelen) experimentally infected by A. hydrophila. However, it is noteworthy that no reports have been found on the possible mechanisms of action of this extract in infected fish. This study aimed to evaluate the effect of the HEHR, administered through single immersion bath, on lipid peroxidation and antioxidant defenses in muscle and liver tissue of silver catfish challenged with A. hydrophila. The results showed that the oxidative status of silver catfish was altered, although oxidative stress was not triggered during the experiment. HEHR at 30 mg/L (HEHR30) was not characterized as a pro-oxidant agent in the presence of infection, unlike florfenicol and HEHR at 15 mg/L treatments in some cases. In short, HEHR30 provided an important increase in hepatic catalase activity, characterizing one of the possible mechanisms involved in the greater survival of fish experimentally infected by A. hydrophila. Additionally, HEHR30 did not induce lipid peroxidation, nor reduced antioxidant defenses of silver catfish infected or not by A. hydrophila.

Structural characterization of vegetative organs of the endangered Brazilian native species Hesperozygis ringens (Benth.) Epling.

The aim of this study was to describe the structural characterization of Hesperozygis ringens (Benth.) Epling vegetative organs. For this purpose, leaves, stems and roots of the endangered Lamiaceae were collected from a population located in Santo Antão, Santa Maria municipality, Rio Grande do Sul, Brazil. Results demonstrated that the H. ringens leaf blade presents glandular and non-glandular trichomes as well as two morphs of diallelocytic stomata, which are usually found above the epidermis level. The petiole is concave on ventral face and convex on its dorsal face, containing glandular and non-glandular trichomes as well as stomata in the epidermis. These types of trichomes were also detected in the stem. In addition, the presence of intercellular spaces within the organ is highlighted. Stomata above epidermis level also occurred in the stem. Phenolic idioblasts were found in the cortical region of plant root and deposit of lipophilic substance was observed in phloem cells. Great amount of apparently two different crystals were detected in all organs. Information obtained in this study provides knowledge about the characterizationof H. ringens, which may be used to distinguish characters of taxa and can help understand the species survival in its occurrence sites.

Essential oils of Cunila galioides and Origanum majorana as anesthetics for Rhamdia quelen: efficacy and effects on ventilation and ionoregulation

This study evaluated anesthetic efficacy and possible effects of the essential oils (EOs) of Cunila galioides (EOC) and Origanum majorana (EOO) on ventilatory rate (VR) and ionoregulation in Rhamdia quelen. In the anesthesia assessments, 50, 100, 200 and 300 μL L-1 EOC and 50, 100, 200, 300, 400 and 500 μL L-1 EOO were tested, and time for induction to sedation and anesthesia stages, as well as recovery, were taken. A second trial employed lower concentrations of both EOs, 10, 25, 50 and 100 μL L-1, in order to verify VR and Na+, K+ and Cl- whole body net fluxes. Sedation was achieved with both oils at 100 µL L-1, and anesthesia at ≥ 200 µL L-1. There was no significant difference between control and EO-treated groups regarding VR, but all fish subjected to 100 µL L-1 EOC died within 2 h of exposure. Overall, ionic loss declined in the presence of the EOs. The EOC at 200 - 300 μL L-1 and EOO at 400 - 500 μL L-1 present the potential to promote fast anesthesia in R. quelen.(AU)

No presente estudo foi avaliada a eficácia da anestesia e possíveis efeitos dos óleos essenciais (EOs) de Cunila galioides (EOC) e Origanum majorana (EOO) sobre a taxa ventilatória (VR) e regulação iônica em Rhamdia quelen. Nas avaliações de anestesia, as concentrações de 50, 100, 200 e 300 μL L-1 EOC e 50, 100, 200, 300, 400 e 500 μL L-1 EOO foram testadas, e os tempos para a indução às fases de sedação e de anestesia, assim como recuperação, foram mensurados. Um segundo ensaio empregou concentrações mais baixas de ambos EOs: 10, 25, 50 e 100 μL L-1 a fim de verificar a VR e o fluxo líquido corporal dos íons Na+, K+ and Cl- . A sedação foi alcançada para ambos os óleos em 100 μL L-1, e a anestesia em concentrações ≥ 200 µL L-1. Não houve diferença significativa entre o controle e grupos tratados com EOs em relação a VR, mas todos os peixes submetidos a 100 µL L-1 do EOC morreram dentro de 2 h de exposição. No geral, a perda iônica declinou na presença dos EOs. O EOC em 200 - 300 μL L-1 e o EOO em 400 - 500 μL L-1 apresentam potencial para anestesia rápida em R. quelen.(AU)

Evaluation of Ocimum americanum essential oil as an additive in red drum (Sciaenops ocellatus) diets.

This study evaluated productive parameters, whole-body composition, non-specific immune responses and pH and microbiota of digestive tract contents of red drum (Sciaenops ocellatus) fed diets supplemented with Ocimum americanum essential oil (OAEO) (0 - control, 0.25, 0.5, 1.0 and 2.0 g/kg diet). After 7 weeks no significant differences in productive parameters and whole-body composition were observed. Plasma and intestinal lysozyme measurements and pH of the stomach and intestine (6 h after feeding) did not show significant differences among groups. Intestinal microbial community in fish fed the basal and OAEO diets (all concentrations) were identical. However, red drum fed the diet with OAEO at 1.0 g/kg had significantly increased intraperitoneal fat deposition and stomach pH (2 h after feeding) and decreased superoxide ion production (NBT-test) compared to the control group. Hemolytic activity of the complement system increased in fish fed diets containing OAEO. Red blood cells from fish fed the lowest OAEO concentration (0.25 g/kg) showed significant lower fragility in erythrocyte osmotic fragility assay, but fish fed 0.5 and 1.0 g/kg showed significant higher erythrocyte fragility. Lysozyme measurement in the supernatant of stomach content was significantly higher in fish fed the diet supplemented at 0.5 g/kg. Based on these various results, OAEO at different supplementation levels did not influence growth performance and intestinal microbial community; however, the EO added to the diet showed effects on immunological responses of red drum.

The simulation of click and double-click through EMG signals.

Patients with severe motor impairments, victims of stroke, amyotrophic lateral sclerosis and spinal cord injury are prevented from oral and gesture communication, demanding alternative channels and methods of communication, possibly using a computer. In order to obtain the complete emulation of a standard mouse, the single-click and double-click actions are desirable functionalities. In this study, the implementation of such actions is executed by the analysis of the electromyographic signal recorded from the Frontalis muscle. Muscle activity is discriminated from noise and this information is used to feed a state-machine that in turn decides which action is intended. The method uses an adaptive threshold, which offers freedom for the selection of the parameters of the system. The rate of successfully detected commands found was up to 100% for the single-click and 92% for the double-click. Even though good results were found for double-clicks, the experiment indicate muscle fatigue in the short term. The time response found was below 300 ms suggesting real-time implementation is feasible. Also, other devices can be operated with this approach, if it is accepted as a two symbols system generator.

Alternative communication systems for people with severe motor disabilities: a survey.

We have now sufficient evidence that using electrical biosignals in the field of Alternative and Augmented Communication is feasible. Additionally, they are particularly suitable in the case of people with severe motor impairment, e.g. people with high-level spinal cord injury or with locked-up syndrome. Developing solutions for them implies that we find ways to use sensors that fit the user's needs and limitations, which in turn impacts the specifications of the system translating the user's intentions into commands. After devising solutions for a given user or profile, the system should be evaluated with an appropriate method, allowing a comparison with other solutions. This paper submits a review of the way three bioelectrical signals--electromyographic, electrooculographic and electroencephalographic--have been utilised in alternative communication with patients suffering severe motor restrictions. It also offers a comparative study of the various methods applied to measure the performance of AAC systems.