ESTRATEGIAS PEDAGÓGICAS PARA LA ENSEÑANZA DE CITOLOGÍA / HISTOLOGÍA PARA LOS ALUMNOS DE LA ENSEÑANZA MEDIA

Estudar biologia sem atividades práticas torna esta disciplina abstrata e monótona. Sabe-se que as atividades práticas contribuem para aprendizagem dos educandos. Temas como Citologia e Histologia necessitam de recursos pedagógicos para que facilite a sedimentação do conhecimento pelos discentes. O objetivo deste projeto de extensão foi ensinar Citologia/Histologia para os alunos do ensino médio com o auxílio de aulas práticas, além de consolidar o manual de protocolos para aulas de Biologia Celular e Histologia dos cursos de Ciências Naturais. Através do levantamento bibliográfico foram escolhidos os protocolos mais viáveis para serem aplicados em sala de aula. Após a seleção destes, os alunos extensionistas foram treinados para ministrarem as aulas de Citologia/Histologia para os alunos do ensino médio. Os objetivos propostos foram alcançados consolidando as práticas de Citologia/Histologia e contribuindo para aprendizagem desta disciplina tanto para os extensionistas como para os alunos do ensino médio.Studying biology without practical activities makes its subjects monotonous and abstract. It is known that practical activities contribute to student learning. Subjects such as cytology and histology need pedagogical resources to facilitate the sedimentation of knowledge by students. The objective of this extension project was to teach Cytology and Histology to high school students with the aid of practical classes, as well as to consolidate a protocol manual for classes in Cell Biology and Histology of the Natural Sciences courses at UFAM. Through the bibliographic survey, the most viable protocols were chosen to be applied in the classroom. After protocols were chosen, extension workers were trained to teach Cytology and Histology classes to high school students. The objectives were achieved by consolidating the practices of Cytology and Histology and contributing to the learning of this discipline for both extension workers and high school students. In this way, the students of IFAM had the opportunity to visualize contents previously only available in theory. Teachers of this public institution can also take advantage of the practices carried out during the project. The production of the Cytology and Histology workbook was and continues to be useful for UFAM teachers since it has been consolidated for continuous use in the practical classes of these disciplines in the Natural Sciences course.Estudiar biología sin actividades prácticas hace que sus asuntos sean monótonos y abstractos. Se sabe que las actividades prácticas contribuyen al aprendizaje de los estudiantes. Temas como Citología e Histología necesitan recursos pedagógicos para que facilite la sedimentación del conocimiento por los discentes. El objetivo de este proyecto de extensión fue enseñar Citología e Histología para los alumnos de la enseñanza media con el auxilio de clases prácticas, además de consolidar un manual de protocolos para clases de Biología Celular e Histología de los cursos de Ciencias Naturales de la UFAM. A través del levantamiento bibliográfico se eligieron los protocolos más viables para ser aplicados en el aula. Después de la selección de éstos, los alumnos extensionistas fueron entrenados para ministrar las clases de Citología e Histología para los alumnos de secundaria. Los objetivos se alcanzaron consolidando las prácticas de Citología e Histología y contribuyendo para el aprendizaje de esta disciplina tanto para los extensionistas como para los alumnos de la secundaria. De esta forma, los alumnos del IFAM tuvieron la oportunidad de visualizar en la práctica los contenidos vistos por ellos solamente en la teoría, al mismo tiempo que los docentes de esa institución pública puedan aprovechar las prácticas realizadas durante el proyecto. La producción de la apostilla de Citología e Histología fue y sigue siendo útil para los profesores de la UFAM una vez que la misma fue consolidada para uso continuo en las clases prácticas de las disciplinas referidas arriba del curso de Ciencias Naturales

Ultrastructure of the midgut in the predator Brontocoris tabidus (Heteroptera: Pentatomidae) after different feeding periods with prey and plant

Este trabalho avaliou alterações ultra-estruturais no intestino médio de Brontocoris tabidus Signoret (Heteroptera: Pentatomidae) causado pelo jejum ou alimentação em diferentes períodos, condição esta que pode ocorrer em seu ambiente natural, sendo esses fatores importantes para o entendimento da evolução do hábito alimentar desse predador. Adultos de B. tabidus receberam diferentes tratamentos (jejum ou alimentado com planta e presa) e seu intestino médio foi dissecado e dividido em anterior, mediano e posterior, as quais foram processadas e analisadas em microscópio de luz e eletrônico de transmissão. O epitélio do intestino médio de B. tabidus é formado por células digestivas e regenerativas. A porção anterior do intestino médio de B. tabidus em jejum ou alimentado com folhas de eucalipto, não apresentou reservas de glicogênio. B. tabidus alimentado com planta apresentou corpos multivesiculares nessa região e esferocristais seis horas após a alimentação com presa. As microvilosidades do intestino médio mediano de B. tabidus são mais longas que as da região anterior e posterior. O intestino médio posterior difere das outras duas partes, por apresentar grande quantidade de mitocôndrias, retículo endoplasmático rugoso e vesículas de dupla membrana na região apical após seis horas de alimentação. As regiões anterior, mediana e posterior do intestino médio de B. tabidus sintetizam enzimas digestivas, absorvem eletrólitos, nutrientes, estocam e excretam substâncias.This work evaluated ultrastrucural alterations in the midgut of Brontocoris tabidus Signoret (Heteroptera: Pentatomidae) caused by the starvig or feeding in differents periods, this condition can occur in its natural enviroment, being those important factors for the understanding the evolution of the alimentary habit of that predator. Adults of the B. tabidus received differents treatments (starvation or feeding with plant and prey) and their midgut were dissected and divided in anterior, medium and posterior, which were processed and analyzed in light and trasmission eletronic microscope. The epitelium of the midgut of B. tabidus is formed by digestive and regenerative cells. The anterior portion of the midgut of B. tabidus starved or feeding on eucalyptus leaves, didn t present glycogen storage. Brontocoris tabidus fed on plant have multivesicular bodies in this region and spherocrystals after six hour the feeding with prey. The microvilli of the medium midgut of B. tabidus are longer than ones of the anterior and posterior midgut. The posterior midgut differs of the other two parts, for presenting great amount the mitochondria, rough endoplasmatic reticule and double membrane vesicules in the apical region six hours after feeding. The anterior, medium and posterior regions of the midgut of B. tabidus synthesize digestive enzimes, absorb eletrolytes and nutrients, stored and excrete substances.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Characterization and Immunolocalization of Major Digestive Enzymes of the Predator Podisus nigrispinus (Heteroptera: Pentatomidae)

Considerando a importância do predador Podisus nigrispinus em programas de controle biológico de pragas e a escassez de estudos sobre as enzimas digestivas deste inseto, este trabalho teve como objetivo identificar, caracterizar e localizar as principais enzimas digestivas das glândulas salivares e do intestino médio de P. nigrispinus. Machos adultos de P. nigrispinus foram dissecados sendo as glândulas salivares e o intestino médio (dividido em anterior, médio e posterior) submetidas a testes enzimáticos para amilase, aminopeptidase, catepsina L, tripsina e α-glicosidase. Estas enzimas foram pré-purificadas e imunolocalizadas na região do intestino médio. O pH da glândula salivar foi 6,0 e do intestino médio foi de 5,6 na região anterior, 5,7 na mediana e 5,8 na posterior. A atividade específica das enzimas nas glândulas salivares e no intestino médio foi respectivamente: amilase 0,01, 21 mU/mg, aminopeptidase 0,19, 3 mU/mg, catepsina L 16, 3800 U/mg e α-glicosidase 0,27, 147 mU/mg de proteína. Tripsina não apresentou atividade no intestino médio, porém na glândula salivar sua atividade específica foi de 7 U/mg de proteína. Catepsina L foi a principal proteinase encontrada em P. nigrispinus e apresentou dois picos de atividade com pH ótimo 5,5 e massa molecular de 14 e 17 e Km de 32 e 11 μM.. Amilase, aminopeptidase, α-glicosidase apresentaram um pH ótimo de 5,1, 5,5, 5,8; Km de 0,1%, 0,03, 5 mM e massa molecular de 43, 125 e 90 respectivamente. Insetos alimentados há uma hora apresentaram diferenças na atividade enzimática de todas as enzimas analisadas e se manteve similar nos outros tempos. Os dados bioquímicos e da imunolocalização mostraram que a amilase, aminopeptidase e α-glicosidase de membrana foram as enzimas mais ativas na região anterior do intestino; já nas regiões mediana e posterior todas as enzimas estão ativas, porém com uma maior atividade de catepsina L e α-glicosidase solúvel. Estes dados mostram que a digestão inicial de carboidratos inicia na região anterior do intestino médio e termina na anterior e mediana. Já a digestão de proteínas tem o início na região mediana e termina na anterior do intestino médio, sugerindo que a membrana perimicrovilar nestes insetos tem um papel na compartimentação da digestão, na qual a anterior está relacionada à absorção de água e também na absorção de aminoácidos obtidos do xilema por esses insetos zoofitófagos.Considering the importance of the predator Podisus nigrispinus in programs of biological control of pests and the poor studies on the digestive enzymes in Hemiptera, this study aimed to identify, locate and characterize the major digestive enzymes of the salivary glands and midgut of P. nigrispinus. Adult males of P. nigrispinus were dissected and the salivary glands and midgut (divided into anterior, middle and posterior) subjected to enzyme tests for amylase, aminopeptidase, cathepsin L, trypsin and α-glucosidase. These enzymes were pre-purified and immunolocalized in the midgut regions. The pH was 6.0 in salivary gland and 5.6, 5.7 and 5.8 in the anterior, median and posterior regions of the midgut, respectively. The specific activity of enzymes in the salivary glands and midgut were respectively: amylase 0.01, 21 mU / mg, aminopeptidase 0.19, 3 mU / mg, cathepsin L 16, 3800 U / mg and α-glucosidase 0.27, 147 mU / mg protein. Trypsin was not active in the midgut, whereas in salivary gland its specific activity was 7 U / mg protein. Cathepsin L was the major proteinase in P. nigrispinus and showed two peaks of activity with optimum pH 5.5 and molecular mass of 14 and 17 kDa and Km 32 and 11 mM. Amylase, aminopeptidase, α-glucosidase had an optimum pH of 5.1, 5.5, 5.8, Km of 0.1%, 0.03, 5 mM and the molecular mass of 43, 125 and 90 kDa respectively. One hour after feeding, P. nigrispinus showed differences in activity of all enzymes tested and remained similar at other periods after feeding. The biochemical and immunolocalization data showed that the amylase, aminopeptidase and α-glucosidase membrane enzymes were more active in the anterior midgut, already in the middle and posterior all the enzymes were active, but with a higher activity of cathepsin L and soluble α-glucosidase. These data show that the initial digestion of carbohydrates begins in the anterior midgut and ends at the anterior and middle midgut, whereas digestion of proteins has its beginning in the middle, and ends at the anterior midgut, suggesting that the perimicrovilllar membrane play a role in compartmentalization of digestion in which the anterior midgut is related to water absorption and amino acid uptake obtained from xylem in this zoophytophagous insects.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Aquaporins in the honeybee crop—a new function for an old organ

Nectar used by bees as a food source is collected and stored in the crop, where it is transported and converted into honey. The production of honey involves water uptake from nectar. However, the crop is a portion of the insect foregut that has been characterized solely as a food storage organ. Aquaporins are integral membrane proteins that function as specific canal for water transport and are abundant in tissues with high water permeability. In this study, we detected five predicted genes for aquaporins in the gut of the honeybee Apis mellifera. We evaluated the aquaporins’ localization in the crop by using an anti-aquaporin antibody produced against the peptide sequence from one of the expressed genes, which was detected in the crop epithelium, particularly in the apical portions of the cells. Furthermore, we also showed an increase in sugar concentration in a sucrose solution collected from the crop lumen a few minutes after feeding, indicating that water uptake occurs during storage of nectar in the crop, suggesting a previously unidentified function for the honeybee crop

Ultrastructure and cytochemistry of salivary glands of the predator Podisus nigrispinus (Hemiptera: Pentatomidae)

Podisus nigrispinus Dallas (Hemiptera: Pentatomidae) is a zoophytophagous insect with a potential for use as a biological control agent in agriculture because nymphs and adults actively prey on various insects by inserting mouthparts and regurgitating the contents of the salivary glands inside the prey, causing rapid paralysis and death. However, the substances found in saliva of P. nigrispinus that causes the death of the prey are unknown. As a first step to identify the component of the saliva of P. nigrispinus, this study evaluated the ultrastructure and cytochemistry of the salivary glands of P. nigrispinus. The salivary system of P. nigrispinus has a pair of principal salivary glands, which are bilobed with a short anterior lobe and a long posterior lobe, and a pair of tubular accessory glands. The principal gland epithelium is composed of a single layer of cells enclosing a large lumen. Epithelial cells of the principal salivary gland vary from cubic to columnar shape, with one or two spherical and well-developed nuclei. Cells of the anterior lobe of the principal salivary gland have an apical surface with narrow, short, and irregular plasma membrane foldings; apical and perinuclear cytoplasm rich in rough endoplasmic reticulum; and mitochondria with tubular cristae. The basal portion of the secretory cells has mitochondria associated with many basal plasma membrane infoldings that are short but form large extracellular canals. Secretory granules with electron-dense core and electron-transparent peripheral are dispersed throughout the cytoplasm. Cells of the posterior lobe of the principal salivary gland are similar to those of the anterior lobe, except for the presence of mitochondria with transverse cristae. The accessory salivary gland cells are columnar with apical microvilli, have well-developed nucleus and cytoplasm rich in rough endoplasmic reticulum, and have secretory granules. Cytochemical tests showed positive reactions for carbohydrate, protein, and acid phosphatase in different regions of the glandular system. The principal salivary glands of P. nigrispinus do not have muscle cells attached to its wall, suggesting that saliva-releasing mechanism may occurs with the participation of some thorax muscles. The cytochemical and ultrastructural features suggest that the principal and accessory salivary glands play a role in protein synthesis of the saliva

Potencial reprodutivo horário do predador de lagartas desfolhadoras do eucalipto: Podisus nigrispinus (Heteroptera: Pentatomidae)

Insetos da subordem Heteroptera apresentam ampla diversidade faunística, incluindo predadores de pragas agrícolas e florestais. Espécies do gênero Podisus destacam-se entre os percevejos predadores no controle biológico de lagartas desfolhadoras de eucalipto, soja, algodão e tomate. O objetivo foi estudar o comportamento reprodutivo e a atividade de predação de Podisus nigrispinus (Heteroptera: Pentatomidae) alimentado com pupas de Tenebrio molitor L. (Coleoptera: Tenebrionidae) em laboratório. Casais desse predador foram acondicionados em potes plásticos de 500 mL com pupas de T. molitor e água em tubos tipo anestésico odontológico, inseridos na tampa desses potes. Foram observados: a postura o acasalamento e a alimentação de machos e fêmeas de P. nigrispinus às 0 h, 6 h, 12 h e 18 h. O porcentual de fêmeas de P. nigrispinus predando foi de 26,26; 24,39; 15,91; e 34,21% e o de machos, de 7,41; 6,20; 4,88; e 5,77%, às 0 h, 6 h, 12 h e 18 h, respectivamente. O maior número de fêmeas ovipositando foi observado às 00 h. A maior porcentagem de fêmeas predando foi às 18 h (32,21%) e a de atividade de postura, à 0 h (50,56% dos ovos depositados), enquanto foram registrados apenas 1,66% dos ovos às 12 h. O número de acasalamentos de P. nigrispinus foi maior às 12 h (34,58%), seguido das 00 h (29,65%), 18 h (22,36%) e 6 h (16,60%).Insects of the sub-order Heteroptera present a wide diversity including predators of agricultural and forest pests. Species of the genus Podisus are important agents of biological control of defoliating caterpillars of eucalyptus, soybem, cotton and tomato. The objective was to study the reproductive behavior and predation rate of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) fed with Tenebrio molitor L. (Coleoptera: Tenebrionidae) pupae in the laboratory. Pairs of this predator were placed in 500 ml plastic pots with T. molitor pupae and water in tubes of anesthetic odontologic type inserted in the lid. The egg masses were removed and matting and feeding of males and females P. nigrispinus were observed at 12:00 AM, 06:00 AM, 12:00 PM and 06:00 PM. The percentages of females of P. nigrispinus predating were 26.26, 24.39, 15.91 and 34.21%, and males 7.41, 6.20, 4.88 e 5.77% at 12:00 AM, 6:00AM, 12:00 PM and 06:00 PM, respectively. The largest number of females of this predator laying eggs was observed at 12:00 AM. The largest percentage of females predating was observed at 6:00 PM (32.21%) and the maximum number of eggs masses laid at 12:00 AM (50.56% of the eggs deposited) while only 1.66% of them were registered at 12:00 AM. The number of mating of P. nigrispinus was higher at 12:00 PM (34.58%) followed by those at 12:00 AM (29.65%) 06:00 PM (22.36%) and 06:00 AM (16.60%)

Degeneration and cell regeneration in the midgut of Podisus nigrispinus (Heteroptera: Pentatomidae) during post-embryonic development

Cell death, proliferation, and differentiation in some developmental stages of insects have been studied in the midgut of ametabolous, which undergo only continuous growth, and holometabolous, which undergo complete metamorphosis. However, in hemimetabolous insects, evolutionarily intermediate between ametabolous and holometabolous, midgut reorganization during the post-embryonic development has been poorly studied. The present study evaluates the post-embryonic development of the midgut of a hemimetabolous insect, Podisus nigrispinus, to test the hypothesis that these insects have programmed cell death and proliferation followed by differentiation of regenerative cells during midgut growth from nymphs to adult. The morphometrical data showed a 6-fold increase in midgut length from the first instar nymph to the adult, which did not result from an increase in the size of the midgut cells, suggesting that the growth of the midgut occurs by an increase in cell number. Cell death was rarely found in the midgut, whereas proliferation of regenerative cells occurred quite frequently. The growth of the midgut of P. nigrispinus appears to result from the proliferation of regenerative cells present in the epithelium; unlike ametabolous and holometabolous insects, the midgut of P. nigrispinus does not undergo extensive remodeling, as shown by the low frequency of digestive cell death

Morphology of the digestive tract of Cladomorphus phyllinus (Phasmatodea: Phasmidae)

The digestive tracts of insects may indicate life history and phylogenetic relationships among different species. Phasmatodea are chewing herbivores with an elongated body shape, which camouflages them on the vegetation on which they feed. This work evaluated the gut structure of the walking stick insect, Cladomorphus phyllinus (Gray 1835) (Phasmatoidea: Phasmidae), with light and scanning electron microscopy. The digestive tract of C. phillynus is an elongated tube with minimal external anatomical differences along its length. There is a short gastric caeca-like structure in the posterior midgut. The crop is an extensively folded storage organ and the proventriculus is covered by a thick cuticle with spine-like projections, which play a role in grinding food. The midgut has 2 anatomical regions probably involved in digestion and absorption of nutrients. The epithelial cells of the anterior midgut have bubbles of apocrine secretion, while the posterior midgut cells have a striated border. Gastric caecae-like projections are found in the posterior midgut. They are enlarged close to the midgut wall, and follow a thin and long filament, which is free in the body cavity. The epithelial cells lining the gastric caecae-like projections are cuboidal with well development striated borders, suggesting involvement in nutrient absorption. The hindgut is divided in an ileum and a rectum. The ileum epithelial cells are covered by cuticle and have cytological traits characteristic of electrolyte and water absorption. The rectum epithelial cells have no obvious absorptive features, but the rectal pads may be involved in water and electrolyte reabsorption. This work reinforces the concept that the anatomy of gut is related to the diet and body shape, and shows that the general pattern of compartmentalization of digestion in insects was maintained in Phasmatodea, but that it differs from other Orthopteroidea in some aspects.O trato digestivo dos insetos pode indicar a história de vida e as relações filogenéticas entre espécies diferentes. Phasmatodea são herbívoros mastigadores com corpo alongado que se camuflam na vegetação. Este trabalho avaliou a estrutura do intestino do bicho-pau Cladomorphus phyllinus através de microscopia de luz e microscopia eletrônica de varredura. O trato digestivo de C. phyllinus é um tubo alongado sem diferenças anatômicas ao longo de seu comprimento, exceto pela presença de uma estrutura semelhante ao ceco gástrico na região posterior do intestino médio. O papo é um órgão de armazenamento amplamente dobrado e o proventrículo é coberto por cutícula espessa com projeções na forma de espinhos. O intestino médio tem duas regiões anatômicas, e está provavelmente envolvido na digestão e absorção de nutrientes. As células epiteliais do intestino médio anterior apresentam bolhas de secreção apócrina na sua porção apical, ao passo que as células do intestino médio posterior possuem borda estriada no ápice. Estruturas semelhantes a cecos gástricos foram encontrados no intestino médio posterior, com células cúbicas que apresentam microvilosidades longas, provavelmente envolvidas na absorção de nutrientes. O intestino posterior é dividido em íleo e reto. As células do íleo são cobertas por cutícula e têm características de absorção de eletrólitos e água. As células epiteliais do reto não apresentam características de células absortivas, diferentemente das células das papilas retais, provavelmente envolvidas na reabsorção de água e eletrólitos. Este trabalho reforça que a anatomia do intestino está relacionada com a forma do corpo do inseto, e mostra que o padrão geral de compartimentalização da digestão nos insetos é mantido em Phasmatodea, mas com algumas diferenças em comparação com outros Orthopteroidea