RESUMEN

We investigated whether Melipona quadrifasciata worker mandibular gland secretions contribute directly to their cuticular hydrocarbon profile. The mandibular gland secretion composition and cuticular surface compounds of newly emerged worker bees, nurse bees, and foragers were determined by gas chromatography and mass spectrometry and compared. Both the mandibular gland secretions and the cuticular surface compounds of all worker stages were found to be composed almost exclusively of hydrocarbons. Although the relative proportion of hydrocarbons from the cuticular surface and gland secretion was statistically different, there was a high similarity in the qualitative composition between these structures in all groups of bees.

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RESUMEN

The present paper shows through conventional light microscopy, silver nitrate impregnation and Transmission Electron Microscopy, the changes in nuclear activity that occurs in the ovary cells during vitellogenesis of Apis mellifera (Linnaeus, 1758). The material impregnated by silver nitrate was detected in nurse cells, oocyte germinal vesicle and follicular cells, whose amounts are greater in phases corresponding to ovarian cells more intense activity. The silver impregnation permitted to demonstrate that the oocyte germinal vesicle synthezises ribonucleoproteins (RNP) during the beginning of the vitellogenesis. The ultrastructure show nucleolar-like material corresponding to nuclear sites impregnated by silver.

Asunto(s)

RESUMEN

The present paper shows through conventional light microscopy, silver nitrate impregnation and Transmission Electron Microscopy, the changes in nuclear activity that occurs in the ovary cells during vitellogenesis of Apis mellifera (Linnaeus, 1758). The material impregnated by silver nitrate was detected in nurse cells, oocyte germinal vesicle and follicular cells, whose amounts are greater in phases corresponding to ovarian cells more intense activity. The silver impregnation permitted to demonstrate that the oocyte germinal vesicle synthezises ribonucleoproteins (RNP) during the beginning of the vitellogenesis. The ultrastructure show nucleolar-like material corresponding to nuclear sites impregnated by silver.

Este estudo mostra, por meio de microscopia convencional, impregnação por nitrato de prata e microscopia eletrônica de transmissão, as mudanças que ocorrem na atividade nuclear de células do ovário durante a vitelogênese de Apis mellifera (Linnaeus, 1758). Material impregnado por nitrato de prata foi detectado no núcleo de células nutridoras, na vesícula germinal do ovócito e no núcleo das células foliculares. As maiores quantidades de material impregnado pela prata foram observadas durante as fases de maior atividade dessas estruturas. A impregnação por prata permitiu demonstrar que a vesícula germinal sintetiza ribonucleoproteínas (RNP) durante o início da vitelogênese. A ultraestrutura mostrou que o material impregnado apresenta características morfológicas de nucléolos.

Asunto(s)

RESUMEN

The present paper shows through conventional light microscopy, silver nitrate impregnation and Transmission Electron Microscopy, the changes in nuclear activity that occurs in the ovary cells during vitellogenesis of Apis mellifera (Linnaeus, 1758). The material impregnated by silver nitrate was detected in nurse cells, oocyte germinal vesicle and follicular cells, whose amounts are greater in phases corresponding to ovarian cells more intense activity. The silver impregnation permitted to demonstrate that the oocyte germinal vesicle synthezises ribonucleoproteins (RNP) during the beginning of the vitellogenesis. The ultrastructure show nucleolar-like material corresponding to nuclear sites impregnated by silver.

Este estudo mostra, por meio de microscopia convencional, impregnação por nitrato de prata e microscopia eletrônica de transmissão, as mudanças que ocorrem na atividade nuclear de células do ovário durante a vitelogênese de Apis mellifera (Linnaeus, 1758). Material impregnado por nitrato de prata foi detectado no núcleo de células nutridoras, na vesícula germinal do ovócito e no núcleo das células foliculares. As maiores quantidades de material impregnado pela prata foram observadas durante as fases de maior atividade dessas estruturas. A impregnação por prata permitiu demonstrar que a vesícula germinal sintetiza ribonucleoproteínas (RNP) durante o início da vitelogênese. A ultraestrutura mostrou que o material impregnado apresenta características morfológicas de nucléolos.

RESUMEN

Histological and histochemical analyses were carried out in order to evaluate the influence of the topical application of a synthetic juvenile hormone on the secretory cycle and degeneration of the venom gland of Apis mellifera. Newly emerged workers received the topical application of synthetic hormone and the results were compared to the normal development of the secretory cycle in virgin and mated queens. The first worker group received the juvenile hormone diluted in hexane (2 microg/microL), the second received only 1 microL of hexane, and the third did not receive any kind of application. After the application the workers were returned to the colony and collected at the ages of 14 and 25 days of adult life. The groups with virgin queens and the other with mated queens, did not receive the treatment. The results show that the individuals treated with juvenile hormone and with pure hexane presented differences in the histological and cytochemical aspects of the secretory cells of the venom gland. The data indicate that both the juvenile hormone and hexane accelerate the activity of the secretory cycle and the degeneration of the venom gland; however, the juvenile hormone proved to be more effective than hexane.

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The germline cells in the ovary of the female bee are interconnected by intercellular bridges kept open by cytoskeletal reinforcements in the plasmic membrane. These bridges among the germline cells display a dynamic behavior and probably act in the determination of the oocyte among the cells of the clone formed by the premeiotic mitoses, subsequently forming a pathway that enables the products synthesized by the nurse cells to reach the oocyte during its maturation. The cytoskeletal elements in the intercellular bridges of bee gonads are basically microfilaments and microtubules, but another type of filament (thick, of non-defined nature, associated with elements of the endoplasmic reticulum) is present in the bridges between the premeiotic cystocytes. This filament crosses the bridge, using microfilaments to fasten itself to the plasmic membrane. These filaments appear to control the span of the bridge. Upon completion of the proliferation phase the cystocytes take on a rosette shape, and a fusome formed by the convergence of the bridges appears at their center. The thick filaments are not present in this conformation. The differentiation of the oocyte and the nurse cells leads to a new change, in which the bridges are reoriented to convey the content of the future nurse cells to the oocyte.

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RESUMEN

No ovário das abelhas as células germinativas e as células foliculares são interconectadas por pontes intercelulares mantidas abertas por reforços do citoesqueleto na membrana plasmática. As pontes entre as células germinativas têm comportamento dinâmico e provavelmente atuam na determinação do ovócito entre as células do clone formado pelas mitoses pré meióticas formando posteriormente uma via de transporte para que os produtos sintetizados pelas células nutridoras atinjam o ovócito durante sua maturação. Os elementos do citoesqueleto presentes nas pontes intercelulares das gônadas das abelhas são basicamente microfilamentos e microtúbulos, mas nas pontes entre os cistócitos pré-meióticos outro tipo de filamento (espesso de natureza não definida, associado a elementos do retículo endoplasmático) está presente, atravessando a ponte e prendendo-se através dos microfilamentos à membrana plasmática. Estes filamentos aparentemente controlam o vão da ponte. Terminada a fase de proliferação os cistócitos tomam a forma de uma roseta e um fusoma, formado pela convergência das pontes, aparece no centro desta. Nesta conformação os filamentos grossos não estão presentes. Nova mudança ocorre com a diferenciação do ovócito e das células nutridoras, com a reorientação de todas as pontes de maneira a canalizar o conteúdo das futuras células nutridoras para o ovócito.

Asunto(s)

RESUMEN

The germline cells in the ovary of the female bee are interconnected by intercellular bridges kept open by cytoskeletal reinforcements in the plasmic membrane. These bridges among the germline cells display a dynamic behavior and probably act in the determination of the oocyte among the cells of the clone formed by the premeiotic mitoses, subsequently forming a pathway that enables the products synthesized by the nurse cells to reach the oocyte during its maturation. The cytoskeletal elements in the intercellular bridges of bee gonads are basically microfilaments and microtubules, but another type of filament (thick, of non-defined nature, associated with elements of the endoplasmic reticulum) is present in the bridges between the premeiotic cystocytes. This filament crosses the bridge, using microfilaments to fasten itself to the plasmic membrane. These filaments appear to control the span of the bridge. Upon completion of the proliferation phase the cystocytes take on a rosette shape, and a fusome formed by the convergence of the bridges appears at their center. The thick filaments are not present in this conformation. The differentiation of the oocyte and the nurse cells leads to a new change, in which the bridges are reoriented to convey the content of the future nurse cells to the oocyte.

No ovário das abelhas as células germinativas e as células foliculares são interconectadas por pontes intercelulares mantidas abertas por reforços do citoesqueleto na membrana plasmática. As pontes entre as células germinativas têm comportamento dinâmico e provavelmente atuam na determinação do ovócito entre as células do clone formado pelas mitoses pré meióticas formando posteriormente uma via de transporte para que os produtos sintetizados pelas células nutridoras atinjam o ovócito durante sua maturação. Os elementos do citoesqueleto presentes nas pontes intercelulares das gônadas das abelhas são basicamente microfilamentos e microtúbulos, mas nas pontes entre os cistócitos pré-meióticos outro tipo de filamento (espesso de natureza não definida, associado a elementos do retículo endoplasmático) está presente, atravessando a ponte e prendendo-se através dos microfilamentos à membrana plasmática. Estes filamentos aparentemente controlam o vão da ponte. Terminada a fase de proliferação os cistócitos tomam a forma de uma roseta e um fusoma, formado pela convergência das pontes, aparece no centro desta. Nesta conformação os filamentos grossos não estão presentes. Nova mudança ocorre com a diferenciação do ovócito e das células nutridoras, com a reorientação de todas as pontes de maneira a canalizar o conteúdo das futuras células nutridoras para o ovócito.

RESUMEN

The germline cells in the ovary of the female bee are interconnected by intercellular bridges kept open by cytoskeletal reinforcements in the plasmic membrane. These bridges among the germline cells display a dynamic behavior and probably act in the determination of the oocyte among the cells of the clone formed by the premeiotic mitoses, subsequently forming a pathway that enables the products synthesized by the nurse cells to reach the oocyte during its maturation. The cytoskeletal elements in the intercellular bridges of bee gonads are basically microfilaments and microtubules, but another type of filament (thick, of non-defined nature, associated with elements of the endoplasmic reticulum) is present in the bridges between the premeiotic cystocytes. This filament crosses the bridge, using microfilaments to fasten itself to the plasmic membrane. These filaments appear to control the span of the bridge. Upon completion of the proliferation phase the cystocytes take on a rosette shape, and a fusome formed by the convergence of the bridges appears at their center. The thick filaments are not present in this conformation. The differentiation of the oocyte and the nurse cells leads to a new change, in which the bridges are reoriented to convey the content of the future nurse cells to the oocyte.

No ovário das abelhas as células germinativas e as células foliculares são interconectadas por pontes intercelulares mantidas abertas por reforços do citoesqueleto na membrana plasmática. As pontes entre as células germinativas têm comportamento dinâmico e provavelmente atuam na determinação do ovócito entre as células do clone formado pelas mitoses pré meióticas formando posteriormente uma via de transporte para que os produtos sintetizados pelas células nutridoras atinjam o ovócito durante sua maturação. Os elementos do citoesqueleto presentes nas pontes intercelulares das gônadas das abelhas são basicamente microfilamentos e microtúbulos, mas nas pontes entre os cistócitos pré-meióticos outro tipo de filamento (espesso de natureza não definida, associado a elementos do retículo endoplasmático) está presente, atravessando a ponte e prendendo-se através dos microfilamentos à membrana plasmática. Estes filamentos aparentemente controlam o vão da ponte. Terminada a fase de proliferação os cistócitos tomam a forma de uma roseta e um fusoma, formado pela convergência das pontes, aparece no centro desta. Nesta conformação os filamentos grossos não estão presentes. Nova mudança ocorre com a diferenciação do ovócito e das células nutridoras, com a reorientação de todas as pontes de maneira a canalizar o conteúdo das futuras células nutridoras para o ovócito.

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An investigation of the histological and ultrastructural changes of Sertoli cells during the male reproductive cycle in Piaractus mesopotamicus was made. The results showed that the Sertoli cell development is closely related with germ cell maturation. Therefore, these cells may have some role in germ cell maturation during the reproductive cycle of this species, whether in forming a tissue framework for the developing spermatogenic cysts, aiding in testes reorganization for a new reproductive cycle, in addition to other possible functions discussed in the text.

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Caste determination in Trigona spinipes Fabricius (Hymenoptera, Apidae, Meliponini) is trophogenic. Larvae that eat about 360 microl of food become queens, while those who consume 36 microl develop into workers. We studied the effect of larval nutrition on the number and length of ovarioles and on ovarian development in fifth instar larvae, white eyed, pink eyed and black-eyed pupae as well as newly emerged adults. All larvae have four ovarioles per ovary, while in queen pupae this number ranged from 8 to 15. Cyst formation, the cell death and other characteristics of ovary morphogenesis were the same regardless of the quantity of food consumed. These results are discussed in relation to caste differentiation in other bees.

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Realizou-se uma investigação das mudanças histológicas e ultra-estruturais das células de Sertoli durante o ciclo reprodutivo de machos de Piaractus mesopotamicus. Os resultados mostraram que o desenvolvimento das células de Sertoli está estritamente relacionado à maturação das células gaméticas. Portanto, as células de Sertoli têm algum papel na maturação das células germinativas durante o ciclo reprodutivo dessa espécie, talvez formando um tecido de sustentação para os cistos espermatogênicos em desenvolvimento, ajudando a reorganização testicular para um novo ciclo reprodutivo, além de outras possíveis funções discutidas no texto.

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We used light and transmission electron microscopy to examine the morphology of the accessory glands of immature and mature adult males of Apis mellifera L. We also made an electrophoretic analysis of the protein content of the mature gland. The glands of the immature male actively secrete a mucous substance that can be seen in the lumen of the gland of the mature male. This secretion stains with mercury bromophenol blue and with periodic acid-Schiff reaction, which stain glyconjugates. The protein content was higher in the lumen secretion than in the gland wall extracts. The electrophoresis patterns of the wall extracts were different from those of the secretion found in the gland lumen.

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Hydrolytic enzymes from hypopharyngeal gland extracts of newly emerged, nurse and foraging workers of two eusocial bees, Scaptotrigona postica, a native Brazilian stingless bee, and the Africanized honey bee (Apis mellifera) in Brazil, were compared. The hypopharyngeal gland is rich in enzymes in both species. Fifteen different enzymes were found in the extracts, with only a few quantitative differences between the species. Some of the enzymes present in the extracts may have intracellular functions, while others seem to be digestive enzymes. Scaptotrigona postica, had lower beta-glucosidase and higher lipase esterase activities than A. mellifera. The differences may be due to different feeding habits and behavioral peculiarities of the two species.

Asunto(s)

RESUMEN

An investigation of the histological and ultrastructural changes of Sertoli cells during the male reproductive cycle in Piaractus mesopotamicus was made. The results showed that the Sertoli cell development is closely related with germ cell maturation. Therefore, these cells may have some role in germ cell maturation during the reproductive cycle of this species, whether in forming a tissue framework for the developing spermatogenic cysts, aiding in testes reorganization for a new reproductive cycle, in addition to other possible functions discussed in the text.

Realizou-se uma investigação das mudanças histológicas e ultra-estruturais das células de Sertoli durante o ciclo reprodutivo de machos de Piaractus mesopotamicus. Os resultados mostraram que o desenvolvimento das células de Sertoli está estritamente relacionado à maturação das células gaméticas. Portanto, as células de Sertoli têm algum papel na maturação das células germinativas durante o ciclo reprodutivo dessa espécie, talvez formando um tecido de sustentação para os cistos espermatogênicos em desenvolvimento, ajudando a reorganização testicular para um novo ciclo reprodutivo, além de outras possíveis funções discutidas no texto.

RESUMEN

We investigated the occurrence and ultrastructurally characterized electrondense nuclear material (nuage) released from the nucleus during oogenesis and early spermatogenesis of Piaractus mesopotamicus, a fish from Pantanal Matogrossense (Brazil) having a seasonal reproductive cycle. The female germ cells presented two instances of nuclear material extrusion: in the oogonia and in the oocyte in the perinucleolar phase. In males, material with similar morphology and behavior occurred in the spematogonia. In all cases, this material was associated to mitochondria. The possible function of this material is discussed.

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Insect mandibular glands are exocrine organs that produce chemical substances known as pheromones that play an important role in intra-specific communication of insects. The mandibular glands of Apis mellifera, which are more highly developed in queens than in workers, present caste-specific polymorphism which seems to be regulated by the juvenile hormone (JH). These glands develop at the pupation stage, during which the titer of JH is higher in queens. In spite of this observation, application recounted here of juvenile hormone on 5th-instar workers' larvae of Apis mellifera did not produce a significant effect on the size of the mandibular glands. Therefore, we may conclude that the response of insect organs to the exogenous application of JH varies according to the type of organ, its developmental program, and its developmental stage, as well as to the amount of hormone applied.

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