Aspectos estruturais e ultraestruturais das espermátides de percevejos fitófagos (Heteroptera: Pentatomidae)
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Data
2020-02-27
Autores
Silva Junior, Fernando Cesar
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Universidade Estadual Paulista (Unesp)
Resumo
Dentro da subordem Heteroptera algumas espécies pertencentes a família Pentatomidae apresentam espermátides polimórficas em seus lobos testiculares que são oriundas de dois fenômenos: a polimegalia e o lobo harlequin. Para a investigação dessas espermátides polimórficas e de seu desenvolvimento comparadas às espermátides não polimórficas, foram coletadas em São José do Rio Preto as espécies Antiteuchus tripterus, Edessa meditabunda, Loxa deducta e Proxys albopunctulatus (Pentatomidae, Heteroptera). Os machos tiveram seus testículos extraídos, fixados e incluídos em parafina ou resina. O material incluído em parafina foi cortado e corado com hematoxilina/eosina (HE) e analisados em microscopia de luz, outros testículos, destas quatro espécies, foram incluídos em resina e analisados em microscópio eletrônico de transmissão (MET). Os testículos A. tripterus são alongados e divididos em 6 lobos, sendo 1 a 3 sem alterações, 4 e 6 com polimegalia e o 5 o lobo harlequin. Foi possível observar, também, que os lobos 4 e 6 possuem espermátides grandes enquanto o 5 apresenta espermátides pequenas. Em MET foi possível observar em todos os lobos a formação da cauda da espermátide onde ocorre a formação dos derivados mitocondriais e a posterior formação do axonema entre os derivados. Além disso, foi detectada a presença de três tipos de espermatozoides no ducto eferente, sendo estes oriundos dos diferentes lobos. Há o espermatozoide maior com morfologia alongada com pequenas protuberâncias em suas extremidades; o intermediário com morfologia reniforme com a extremidade apical maior que a extremidade basal e o menor e o mais arredondado quando comparado aos demais. Já nas espécies E. meditabunda, L. deducta e P. albopunctulatus foi possível se observar a morfologia do testículo e formação da cauda dos espermatozoides onde em E. meditabunda o testículo apresentou quatro lobos todos sem alterações, também se observou só um tipo de espermátide com forma arredondada que dá origem a um tipo de espermatozoide, já L. deducta apresentou sete lobos testiculares sendo o 5 o harlequin e os demais sem alterações. Foi possível observar a presença de um tipo maior e arredondado de espermátide oriunda dos lobos sem alterações e um tipo menor e de morfologia irregular originado do lobo harlequin, sendo possível observar dois tipos de espermatozoides no ducto eferente onde o primeiro tipo é menor e mais arredondado, com pequenas estruturas paracristalinas em seu interior e o segundo tipo é maior e mais retangular e com grandes estruturas paracristalinas. Em P. albopunctulatus se observou seis lobos testiculares, sendo o 4 e 6 com polimegalia e os demais sem alterações, também foi possível visualizar espermátides normais e arredondadas presentes nos lobos sem alterações, enquanto nos lobos com polimegalia estavam presentes espermátides gigantes com muitas mitocôndrias e vesículas em seu citoplasma Já a compactação da cromatina ocorreu de maneira semelhante nas espécies estudadas, ela se torna finamente granulada e começa a se aglomerar onde dá origem a cromatina filamentar que se aglomera para preencher o núcleo se tornando completamente compactada. Esse processo ocorre de maneira muito semelhante nas espermátides oriundas de lobos sem alterações, com polimegalia e do harlequin, além de que nas espermátides do lobo harlequin foram encontradas todas as estruturas que compõem a cabeça dos espermatozoides.. Portanto com este estudo podemos concluir que na espécie A. tripterus e L. deducta, os seus diferentes lobos testiculares produzem diferentes tipos de espermatozoides, sendo que estes apresentam todas as estruturas necessárias para serem funcionais e que estes diferem morfologicamente entre si, a formação dos componentes da cabeça e da cauda dos espermatozoides se da de maneira semelhante nas quatro espécies e em outros insetos estudados, a condensação da cromatina se deu de maneira semelhante em A. tripterus e L. deducta seguindo um padrão anteriormente descrito. Existem diferenças morfológicas entre os derivados mitocondriais das espécies estudadas e até mesmo na mesma espécie em espermatozoides oriundos de diferentes lobos testiculares o que pode fazer que através de novos estudos esses caracteres morfológicos sejam usados como ferramentas de identificação de novas espécies.
Within the suborder Heteroptera, some species belonging to the Pentatomidae family show alterations in some of their testicular lobes, where we can show the polymegaly and the harlequin lobe. For the investigation of these polymorphic cells and their development compared to non-polymorphic cells, the species Antiteuchus tripterus, Edessa meditabunda, Loxa deducta and Proxys albopunctulatus (Pentatomidae, Heteroptera) were collected in São José do Rio Preto. The males had their testicles extracted, fixed and included in paraffin or resin. The material included in paraffin was cut and stained with hematoxylin / eosin (HE) and analyzed under light microscopy, other testicles, of these four species, were included in resin and analyzed using a transmission electron microscope (TEM). The testicles A. tripterus are elongated and divided into 6 lobes, 1 to 3 without changes, 4 and 6 with polymegaly and the 5 the harlequin lobe. It was also possible to observe that lobes 4 and 6 have large cells while 5 has small cells. In TEM, it was possible to observe the formation of the sperm tail in all lobes where the formation of the mitochondrial complex occurs, which divides into two mitochondrial derivatives and the subsequent formation of the axoneme between the derivatives. In addition, the presence of three types of sperm in the efferent duct was detected, these coming from different lobes. There is the larger sperm with elongated morphology with small protuberances at its ends; the intermediate with reniform morphology with the apical extremity larger than the basal extremity and the smaller and more rounded when compared to the others. The chromatin compaction, on the other hand, becomes finely granulated and begins to clump where it gives rise to the filamentary chromatin that clusters to fill the nucleus and becomes completely compacted. This process occurred in a very similar way in the sperm cells from lobes without changes, with polyimegaly. and the harlequin, besides that in the harlequin lobe sperm cells all the structures that make up the head of the spermatozoa were found. In the E. meditabunda, L. deducta and P. albopunctulatus species, it was possible to observe the testis morphology and the formation of the sperm's tail, whereas in E. meditabunda the testis showed four lobes, all without alterations, only one type of sperm was also observed. with a rounded shape that gives rise to a type of sperm, L. deducta presented seven testicular lobes, the 5 being the harlequin and the others without alterations. It was possible to observe the presence of a larger and rounded type of sperm from the lobes without alterations and a smaller type and irregular morphology originating from the harlequin lobe, being possible to observe two types of spermatozoa in the efferent duct where the first type is smaller and more rounded, with small paracrystalline structures inside and the second type is larger and more rectangular and with large paracrystalline structures. In P. albopunctulatus, six testicular lobes were observed, with 4 and 6 with polyimegaly and the others without changes, it was also possible to see normal and rounded spermatids present in the lobes without changes, while in the lobes with polyimegaly, giant spermatids were present with many mitochondria and vesicles in your cytoplasm. Also in L. deducta the condensation of the chromatin observed occurred in a very similar way in the spermatids originating from lobes without alterations and from the harlequin to that previously described for A. tripterus. Therefore, with this study we were able to conclude that in the species A. tripterus and L. deducta, their different testicular lobes produce different types of sperm, which have all the necessary structures to be functional and that these differ morphologically, the formation of components of the head and tail of the sperm are similar in the four species and in other insects studied, the chromatin condensation occurred in a similar way in A. tripterus and L. deducta following a pattern previously described. There are morphological differences between the mitochondrial derivatives of the studied species and even in the same species in spermatozoa from different testicular lobes, which may cause these morphological characters to be used as tools to identify new species through new studies.
Within the suborder Heteroptera, some species belonging to the Pentatomidae family show alterations in some of their testicular lobes, where we can show the polymegaly and the harlequin lobe. For the investigation of these polymorphic cells and their development compared to non-polymorphic cells, the species Antiteuchus tripterus, Edessa meditabunda, Loxa deducta and Proxys albopunctulatus (Pentatomidae, Heteroptera) were collected in São José do Rio Preto. The males had their testicles extracted, fixed and included in paraffin or resin. The material included in paraffin was cut and stained with hematoxylin / eosin (HE) and analyzed under light microscopy, other testicles, of these four species, were included in resin and analyzed using a transmission electron microscope (TEM). The testicles A. tripterus are elongated and divided into 6 lobes, 1 to 3 without changes, 4 and 6 with polymegaly and the 5 the harlequin lobe. It was also possible to observe that lobes 4 and 6 have large cells while 5 has small cells. In TEM, it was possible to observe the formation of the sperm tail in all lobes where the formation of the mitochondrial complex occurs, which divides into two mitochondrial derivatives and the subsequent formation of the axoneme between the derivatives. In addition, the presence of three types of sperm in the efferent duct was detected, these coming from different lobes. There is the larger sperm with elongated morphology with small protuberances at its ends; the intermediate with reniform morphology with the apical extremity larger than the basal extremity and the smaller and more rounded when compared to the others. The chromatin compaction, on the other hand, becomes finely granulated and begins to clump where it gives rise to the filamentary chromatin that clusters to fill the nucleus and becomes completely compacted. This process occurred in a very similar way in the sperm cells from lobes without changes, with polyimegaly. and the harlequin, besides that in the harlequin lobe sperm cells all the structures that make up the head of the spermatozoa were found. In the E. meditabunda, L. deducta and P. albopunctulatus species, it was possible to observe the testis morphology and the formation of the sperm's tail, whereas in E. meditabunda the testis showed four lobes, all without alterations, only one type of sperm was also observed. with a rounded shape that gives rise to a type of sperm, L. deducta presented seven testicular lobes, the 5 being the harlequin and the others without alterations. It was possible to observe the presence of a larger and rounded type of sperm from the lobes without alterations and a smaller type and irregular morphology originating from the harlequin lobe, being possible to observe two types of spermatozoa in the efferent duct where the first type is smaller and more rounded, with small paracrystalline structures inside and the second type is larger and more rectangular and with large paracrystalline structures. In P. albopunctulatus, six testicular lobes were observed, with 4 and 6 with polyimegaly and the others without changes, it was also possible to see normal and rounded spermatids present in the lobes without changes, while in the lobes with polyimegaly, giant spermatids were present with many mitochondria and vesicles in your cytoplasm. Also in L. deducta the condensation of the chromatin observed occurred in a very similar way in the spermatids originating from lobes without alterations and from the harlequin to that previously described for A. tripterus. Therefore, with this study we were able to conclude that in the species A. tripterus and L. deducta, their different testicular lobes produce different types of sperm, which have all the necessary structures to be functional and that these differ morphologically, the formation of components of the head and tail of the sperm are similar in the four species and in other insects studied, the chromatin condensation occurred in a similar way in A. tripterus and L. deducta following a pattern previously described. There are morphological differences between the mitochondrial derivatives of the studied species and even in the same species in spermatozoa from different testicular lobes, which may cause these morphological characters to be used as tools to identify new species through new studies.
Descrição
Palavras-chave
Polimorfismos, Polimegalia, Lobo harlequin, Polymorphisms, Polimegaly, Harlequin lobe