Microscopic aspects of electrosensory system on the partially euryhaline lesser guitarfish

ABSTRACT The electrosensory system on elasmobranchs consists of subcutaneous electroreceptor organs known as ampullae of Lorenzini. The present study investigated the ampullae of Lorenzini morphology of the lesser guitarfish Zapteryx brevirostris, using light microscopy and scanning electron microscopy. The pore number found in the ventral skin surface is much higher than that found in the dorsal portion, characteristic of species that inhabit the euphotic zone. Under light microscopy it was possible to observe that the wall canal consists of a single layer of squamous epithelial cells. The canal features distal expansion, where the ampullae are located with up to six alveoli. The sensory epithelium of ampullae is composed by cubic cells, with oval nucleus, restricted to the interior of the alveoli. With analysis the clusters under scanning electron microscopy, it was possible to observe the structure and the random arrangement of individual ampullae, canals and nerves. The distribution of dorsal and ventral pores and ampullae in Z. brevirostris resembled those of the same family. The number of alveoli per ampullae was similar to that found in euryhaline elasmobranchs species, suggesting that the morphological organization in Z. brevirostris is linked to its possible evolutionary transitory position among batoids.

Antennal sensilla of grasshoppers (Orthoptera: Acrididae) in relation to food preferences and habits.

The external structure, i.e. number and distribution of sensillae on male and female antennae of 12 species of grasshoppers belonging to Pamphaginae, Catantopinae, Oedipodinae and Gomphocerinae in the grasslands of Inner Mongolia was investigated using scanning electron microscopy. Five major types of antennal sensillae were detected--trichoid, long basiconic, short basiconic, slender and short basiconic, and coeloconic sensillae. Total number of antennal sensillae varied among different sexes, subfamilies, feeding groups, life forms and eco-forms. Males showed significantly more sensillae than females, due to presence of more short basiconic and coeloconic sensillae. Species under Catantopinae showed more long basiconic sensillae than the others. The Oedipodinae had the highest number of slender and short basiconic sensillae and coeloconic sensillae, followed by Catantopinae and Gomphocerinae; while Pamphaginae had the fewest. The total number of sensillae showed the same trend for these two types amongst the subfamilies as well, species which prefer habits on the ground possessed fewer antennal sensillae than species which prefer to stay on plants. The maximal number of antennal sensillae were observed in hygrophytous species, Chorthippus albomarginatus, in the 12 grasshopper species investigated, although the data is not statistically significant. The general trend which emerged was that species feeding on grass possessed more antennal sensillae, particularly coeloconic sensillae, compared to other feeding group species.

Is the number of antennal plate organs (sensilla placodea) greater in hygienic than in non-hygienic Africanized honey bees?

Hygienic behavior is a desirable trait in honey bees (Apis mellifera L.), as hygienic bees quickly remove diseased brood, interrupting the infectious cycle. Hygienic lines of honey bees appear to be more sensitive to the odors of dead and diseased honey bee brood, and Africanized honey bees are generally more hygienic than are European honey bees. We compared the number of sensilla placodea, antennal sensory structures involved in the perception of odor, in 10 bees from each of six hygienic and four non-hygienic colonies of Africanized honey bees. The sensilla placodea of three of the terminal segments (flagellomeres) of the right antenna of each bee were counted with a scanning electron microscope. There were no significant differences in the mean numbers of sensilla placodea between the hygienic and non-hygienic bees, though the variance was higher in the hygienic group. Flagellomere 4 had significantly more sensilla placodea than flagellomeres 6 and 8. However, there was no significant difference between the other two flagellomeres. As hygienic bees are capable of identifying dead, injured, or infested brood inside a capped brood cell, sensilla placodea probably have an important role in enabling worker bees to sense sick brood. However, we did not find greater numbers of this sensory structure in the antennae of hygienic, compared to non-hygienic Africanized honey bees

Implicações do fumo na gustação e na olfação: revisando o tema / Implications of Smoke Habit in Gustation and in Olfaction: reviewing the theme

Entre os diversos malefícios causados pelo tabagismo, os efeitos na gustação e na olfação não têm sido abordados pela literatura especializada nacional. Realizou-se um estudo de revisão sobre o tema. Há um predomínio de estudos que se dedicam à investigação da gustação. A exposição ao fumo parece alterar significativamente os dois sistemas quimiorreceptores. A capacidade gustativa está comprometida, quanto à percepção de substâncias salgadas, amargas e doces-principalmente as duas últimas -, bem como à impressão hedônica global (prazer). Dessa forma, a preferência alimentar pode variar. Já na olfação, há alterações ultraestruturais no epitélio, perda na habilidade de identificação de odores (hiposmia) e sensação de queimação e dor na mucosa. Talvez com o esclarecimento da importância desses dois sistemas sensórios e de suas patologias, possam ser efetuados novas revisões e estudos sobre o tema em nosso meio.

Among the variety of general health smoking habit consequences, the effects on gustation and on olfacion have not been reported in the national specialized literature. We did a review study about the issue. There is a predominance of study inquirements on gustation. The smoking habit seems to affect both sensory systems. The gustatory capacity is compromised by a reduction in taste sensibility to salty, bitter and sweet substances (specially the last two), as well by a diminish global hedonic impression (pleasure). Therefore, alimentary preferences may change in smokers. The olfaction is compromised by ultra-estrucutral epithelial alterations. The smell identification ability is reduced (hyposmia), and a sensation of burn and pain on the mucosa is also established. The importance of understanding both sensory systems and their pathology suggests new study requirements among our academic staff.

Importância dos sentidos naturais em estomatologia / The importance of natural senses in stomatology

Neste trabalho os autores procuram destacar a importância dos sentidos naturais na elaboraçäo do diagóstico clínico em Estomatologia e sublinha a ascendência dos sinais sobre os sintomas e faz uma exposiçäo dos sentidos naturais mais utilizados em Semiologia, quais sejam: visäo, palpaçäo, auscultaçäo e olfaçäo e relaciona suas limitaçöes, vantagens e desvantagens de cada um e completa com uma relaçäo concisa dos principais distúrbios relacionados com a possibilidade de percepçäo através dos sentidos naturais