Nuclear activity in Apis mellifera L. (Hymenoptera, Apidae) queen ovary cells demonstrated by silver nitrate impregnation and ultrastructure.

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.

Ultrastructural aspects of the intercellular bridges between female bee germ cells.

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.

Ultrastructural aspects of the intercellular bridges between female bee germ cells

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.

Ultrastructural aspects of the intercellular bridges between female bee germ cells

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.

Mating influence in the ovary differentiation in adult queens of Apis mellifera L. (Hymenoptera, Apidae)

The present results show that in the ovarioles of a newly emerged (0 day) queen of A. mellifera only two regions may be distinguished: a proximal, short germarium and a very long distal, terminal filament. As the queen matures and gets ready for the nupcial flight, the germarium increases in lenght, advancing towered the distal end, as the terminal filament shortens. The ovarioles of queens ready to mate (6 to 8 days old) have, already one or two ovarian follicles, i.e. a very short proximal vitellarium, but a real vitellogenesis only starts after the fecundation. If the queen does not mate the ovarioles structure is disrupted (12-16 days old). In mated queen eggs the ovarioles present three differentiated regions, from the apice to the basis: a short terminal filament, a medium size germarium, and a very long basal vitellarium. As the eggs are laid, the emptied follicle collapses, degenerates and produces a corpus luteum

Mating influence in the ovary differentiation in adult queens of Apis mellifera L. (Hymenoptera, Apidae).

The present results show that in the ovarioles of a newly emerged (0 day) queen of A. mellifera only two regions may be distinguished: a proximal, short germarium and a very long distal, terminal filament. As the queen matures and gets ready for the nuptial flight, the germarium increases in length, advancing towered the distal end, as the terminal filament shortens. The ovarioles of queens ready to mate (6 to 8 days old) have, already one or two ovarian follicles, i.e. a very short proximal vitellarium, but a real vitellogenesis only starts after the fecundation. If the queen does not mate the ovarioles structure is disrupted (12-16 days old). In mated queen eggs the ovarioles present three differentiated regions, from the apice to the basis: a short terminal filament, a medium size germarium, and a very long basal vitellarium. As the eggs are laid, the emptied follicle collapses, degenerates and produces a corpus luteum.

Mating influence in the ovary differentiation in adult queens of Apis mellifera L. (Hymenoptera, Apidae)

The present results show that in the ovarioles of a newly emerged (0 day) queen of A. mellifera only two regions may be distinguished: a proximal, short germarium and a very long distal, terminal filament. As the queen matures and gets ready for the nupcial flight, the germarium increases in lenght, advancing towered the distal end, as the terminal filament shortens. The ovarioles of queens ready to mate (6 to 8 days old) have, already one or two ovarian follicles, i.e. a very short proximal vitellarium, but a real vitellogenesis only starts after the fecundation. If the queen does not mate the ovarioles structure is disrupted (12-16 days old). In mated queen eggs the ovarioles present three differentiated regions, from the apice to the basis: a short terminal filament, a medium size germarium, and a very long basal vitellarium. As the eggs are laid, the emptied follicle collapses, degenerates and produces a corpus luteum.

Os resultados do presente trabalho demonstram que nos ovaríolos da rainha de Apis mellifera recém-emergida (0 dia) apenas duas regiões podem ser distinguidas: um curto germário proximal e um longo filamento terminal distal. À medida que a rainha amadurece e fica pronta para o vôo nupcial, o comprimento do germário aumenta e avança em direção à região distal e o filamento terminal diminui. Os ovaríolos da rainha pronta para acasalar (6 a 8 dias) têm 1 ou 2 folículos ovarianos, isto é, um vitelário proximal muito pequeno, mas a vitelogênese propriamente dita somente se inicia após a fecundação. Nas rainhas não acasaladas os ovaríolos se desestruturam (12-16 dias). Nas rainhas acasaladas os ovários apresentam os ovaríolos divididos em três regiões, do ápice para a base: um filamento terminal pequeno, um germário médio e um vitelário muito longo. Quando os ovos são postos, os folículos esvaziados colapsam, produzem um corpo lúteo e finalmente degeneram.

A block to mRNA nuclear export in S. cerevisiae leads to hyperadenylation of transcripts that accumulate at the site of transcription.

Several factors contribute to nuclear mRNA export in Saccharomyces cerevisiae, including Mex67p, Mtr2p, Gle1p, Nup159p, Dbp5p, and Rip1p. Strains carrying mutations in these factors show rapid and dramatic nuclear accumulation of poly(A)(+) RNA. We have characterized two heat shock mRNAs, SSA4 and HSP104, in these mutant backgrounds; each transcript concentrates in a single intranuclear focus. Evidence suggests that it coincides with the site of transcription. Interestingly, all detectable SSA4 transcripts have undergone 3'-end formation, indicating that RNAs in the foci are no longer nascent. Poly(A) tails of the transcripts are also dramatically longer in all of these export mutants. Based on all of the data, we suggest that very early mRNA maturation events determine transcript export competence.

Atividade antiinflamatória, antiúlcera gástrica e toxicidade subcrônica do extrato etanólico de própolis / Anti-inflammatory activity, gastric antiulcer and subchronic toxicity of the ethanol extract of propolis

Avaliou-se a atividade antiinflamatória do extrato etanólico de própolis - EEP, . sobre o edema desencadeado por carragenina, dextrana e histamina. O EEP apresentou dose eficaz (DE50) de 650 mg/kg (v.o), inibindo significativamente o processo inflamatório desencadeado pela carragenina, mas não inibiu o produzido por dextrana. O EEP antagonizou ainda o efeito edematogênico produzido por histamina. Nas úlceras produzidas por estresse, o EPP inibiu de forma significativa a geração dos diversos tipos classificados. Em todos os parâmetros analisados no estudo da toxicidade em fase de tratamento subcrônico , (hematológicos, bioquímicos e histopatológicos), o grupo tratado com o EEP não apresentou diferença significativa em relação ao grupo controle. Desta forma, sugere-se que na dose de 650 mg/kg (dose eficaz) não existe a presença de efeitos tóxicos que possam comprometer a utilização deste extrato.

The antlinflammatory activity of Ethanolic Extract of Propolis - EEP was evaluated on edema induced by carrageenan, dextran and hystamine. The inflammatory process induced by carrageenan was significantly reduced by the treatment with EEP (650 mg/kg, p.o), while it did not interfere in the response induced by dextran. The EEP antagonized the edematous effect produced by hystamine. The EEP promoted a significant inhibition in the generation of the ulcers induced by stress (p < 0.05). The hematological, biochemical and histopathological parameters presented no differences between treated and control groups. Therefore it can be concluded that the effective dose of 650 mg/kg of the EEP has no toxic effect which may compromise the use of this extract.

Anti-inflammatory activity of the crude extract from the fruits of Pterodon emarginatus Vog.

The vegetal species Pterodon emarginatus Vog. (Leguminosae/Papilonaceae), popularly known in Brazil as 'sucupira branca', is widely used by domestic medicine as an anti-inflammatory. From these observations, the hexanic crude extract (HCE) of the fruits was obtained and submitted for assessment of its anti-inflammatory activity. For this purpose, the following tests were used: (1) Determination of ED50 and LD50; (2) Paw edema induced by carrageenin, dextran, histamine and nystatin; (3) Peritonitis caused by carrageenin and (4) Granuloma test. The ED50 (oral) in the edema induced by carrageenin was 500 mg/kg, and LD50 (oral) was 4.02 g/kg. In the edema caused by nystatin, there was a significant inhibition by 45% (P < 0.05 student's t-test) at the 6th hour following the treatment. In the granuloma test performed in animals treated with HCE, there was an inhibition of the granulomatous tissue formation by 22%. The migration of neutrophils towards the peritoneal cavity was inhibited in HCE treated animals by 43% (P < 0.05). However, in the edema caused by dextran and histamine, there was no significant response in HCE treated animals.