RESUMEN
The vitellogenin receptor (VgR) is essential for the uptake and transport of the yolk precursor, vitellogenin (Vg). Vg is synthesized in the fat body, released in the hemolymph, and absorbed in the ovaries, via receptor-mediated endocytosis. Besides its important role in the reproductive pathway, Vg occurs in nonreproductive worker honey bee, suggesting its participation in other pathways. The objective was to verify if the VgR occurs in the hypopharyngeal glands of Apis mellifera workers and how Vg is internalized by these cells. VgR occurrence in the hypopharyngeal glands was evaluated by qPCR analyses of VgR and immunohistochemistry in workers with different tasks. The VgR gene is expressed in the hypopharyngeal glands of workers with higher transcript levels in nurse honey bees. VgR is more expressed in 11-day-old workers from queenright colonies, compared to orphan ones. Nurse workers with developed hypopharyngeal glands present higher VgR transcripts than those with poorly developed glands. The immunohistochemistry results showed the co-localization of Vg, VgR and clathrin (protein that plays a major role in the formation of coated vesicles in endocytosis) in the hypopharyngeal glands, suggesting receptor-mediated endocytosis. The results demonstrate that VgR performs the transport of Vg to the hypopharyngeal glands, supporting the Ovary Ground Plan Hypothesis and contributing to the understanding of the role of this gland in the social context of honey bees.
Asunto(s)
Proteínas del Huevo , Hipofaringe , Proteínas de Insectos , Receptores de Superficie Celular , Animales , Abejas/metabolismo , Abejas/genética , Receptores de Superficie Celular/metabolismo , Receptores de Superficie Celular/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Proteínas del Huevo/metabolismo , Proteínas del Huevo/genética , Hipofaringe/metabolismo , Femenino , Vitelogeninas/metabolismo , Vitelogeninas/genética , Clatrina/metabolismoRESUMEN
Bovine alphaherpesvirus 1 (BHV1) is an agent associated with reproductive disease in cattle. Viral pathogenicity is related to disorders such as temporary infertility, embryonic death, and abortions in affected animals. Considering that natural infections in genital organs of males are understudied, this investigation evaluated the presence of BHV1 in both testicular and epididymal tissues obtained from naturally infected bulls by the evaluation of the presence of the BHV1 genome and antigens. Sixty samples of blood and genital organs of 60 bulls that were not vaccinated against BHV1 were assayed. Fragments from testes and head, body, and tail of epididymides were processed and analyzed by nested PCR and immunofluorescence with confocal laser scanning microscopy. Also, the BHV1 gB glycoprotein gene of 14 positive samples was partially sequenced. The percentage of BHV1 presence obtained by the immunolocalization assay corresponded to 95.9% of the testes, 100% of the epidydimal tissue in the head and tail portions, and 98% of the epididymal body. The nested PCR assay detected the viral nucleic acid in 59.2% of the testicular tissue and in 65.3, 75.5, and 83.7% of epididymis head, body, and tail samples, respectively. The partial sequences analyzed presented 100% of identity with other BHV1 strains. Accordingly, BHV1 detection in testes and epididymides of naturally infected bulls suggests that these organs may be sources of viral infection for semen.
Asunto(s)
Epidídimo , Herpesvirus Bovino 1 , Mataderos , Aborto Veterinario , Animales , Bovinos , Femenino , Masculino , Embarazo , TestículoRESUMEN
Vitellogenin is the main yolk precursor protein in insect oocytes. It is synthesized in the fat body and released into the hemolymph. To reach the oocyte surface, vitellogenin must cross a single layer of follicular epithelium cells. The transport of vitellogenin across the follicular epithelium has been suggested to occur through the enlarged intercellular spaces (patency) by a paracellular route or by endocytosis by follicular cells and release onto oocyte surface in a transcelluar route. In this study, we investigated whether vitellogenin transport in the meroistic telotrophic ovary of Podisus nigrispinus (Hemiptera) occurs via a paracellular or transcellular route. Light and transmission electron microscopies showed that short cell-cell contacts with well-developed occluding septate junctions were present in follicular cells with patency. Immunofluorescence microscopy revealed the presence of vitellogenin receptors in the plasma membrane and of vitellogenin in the cytoplasm of follicular cells. Data suggest that cell-cell contacts serve as a barrier to large vitellogenin molecules and that this protein is transported via a transcellular route of receptor-mediated endocytosis.
Asunto(s)
Hemípteros/fisiología , Oocitos/metabolismo , Ovario/metabolismo , Vitelogeninas/metabolismo , Animales , Femenino , Técnica del Anticuerpo Fluorescente , Oocitos/ultraestructura , Ovario/ultraestructura , Transporte de ProteínasRESUMEN
Vitellogenin receptor (VgR) is a low-density lipoprotein receptor responsible for the mediated endocytosis of vitellogenin (Vg) during egg formation in insects. The maturing oocyte is enveloped by a follicular epithelium, which has large intercellular spaces during Vg accumulation (patency). However, Vg has been reported in the cytoplasm of follicular cells, indicating that there may be a transcellular route for its transport. This study verified the presence of VgR in the follicular cells of the ovaries of the honeybee Apis mellifera and the wasp Polistes simillimus in order to evaluate if Vg is transported via transcytosis in these insects. Antibodies specific for vitellogenin receptor (anti-VgR), vitellogenin (anti-Vg), and clathrin (anti-Clt) were used for immunolocalization. The results showed the presence of VgR on the apical and basal plasma membranes of follicular cells of the vitellogenic follicles in both species, indicating that VgR may have been transported from the basal to the apical cell domain, followed by its release into the perivitelline space, evidenced by the presence of apical plasma membrane projections containing VgR. Co-localization proved that Vg bind to VgR and that the transport of this protein is mediated by clathrin. These data suggest that, in these social insects, Vg is transported via clathrin-mediated VgR transcytosis in follicular cells.