1000 resultados para nurse cells
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In this work we describe the internal morphology of the female reproductive system of the cayenne tick Amblyomma cajennense. This system is represented by a panoistic ovary, which lacks nurse cells in the germarium. This ovary consists of a single tube, in which a large number of oocytes develop asynchronously, thus accompanying the processes of yolk deposition in the oocytes. The oocytes were classified into stages that varied from I to V, according to: cytoplasm appearance, presence of the germ vesicle, presence of yolk granules, and presence of chorion. The study of vitellogenesis dynamics suggest that the yolk elements are deposited in the oocyte following a preferencial sequence, in which the lipids are the first to appear, followed by proteins an finally by the carbohydrates. In this way the yolk of A. cajennense ticks have these three elements that may be free in the cytoplasm or chemically bounded forming glycoprotein or lipoprotein complexes. (C) 2004 Elsevier B.V. All rights reserved.
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This study presents the morphology of the ovary, as well as the process of the vitellogenesis in oocytes of the tick Rhipicephalus sanguineus. The ovary of these individuals is of the panoistic type; therefore, it lacks nurse cells. This organ consists of a single tubular structure, continuous, and composed of a wall formed by small epithelial cells with rounded nuclei which delimit the lumen. The oocytes in the different developmental stages in this tick species were classified into five stages (I V). They remain attached to the ovary during vitellogenesis by a cellular pedicel and afterwards the mature oocytes (stage V) are released into the ovary lumen. (c) 2005 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The present study describes the ultrastructure of meroistic telotrophic ovaries of the sugarcane spittlebug Mahanarva fimbriolata. In this type of ovary, nurse cells, oogonia, and prefollicular tissue are located at the terminal (distal) regions or tropharium of ovarioles. Oocytes in different developmental stages, classified from I to V, are observed in the vitellarium. Stage I oocytes do not exhibit intercellular spaces in the follicular epithelium, suggesting that synthesis and production of yolk during this stage occurs only through endogenous processes. Small yolk granules of different electron densities are present in the cytoplasm. Few lipid droplets are observed. Stage 11 oocytes exhibit small intercellular spaces in the follicular epithelium. More protein as well as lipid yolk granules are observed in the cytoplasm. In stage III oocytes, intercellular spaces in the follicular epithelium are larger than those observed in the previous stage. Electrondense protein granules of various sizes, larger than those observed in stage 11 oocytes predominate in the cytoplasm. Smaller lipid droplets are also present. In stage IV oocytes, the follicular epithelium exhibits large intercellular spaces. Our data clearly indicate that the opening of these spaces in the follicular epithelium of M. fimbriolata oocytes increases as the intake of exogenous proteins intensifies, that is, in stages IV and Voocytes. During these stages, granular yolk becomes viscous due to the lysis of granules. In stage Voocytes, viscous yolk predominates in the cytoplasm. This type of yolk, however, has not been described for other orders of insects. The chorion of M. fimbriolata oocytes consists of an external layer (exochorion) and an internal one (endochorion), which is in direct contact with the oocyte. Numerous small pores that probably facilitate oxygenation of the internal structures inside the eggs are observed in the exochorion. (c) 2006 Elsevier Ltd. All rights reserved.
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The present study aimed describing the ovaries of the sugarcane spittlebug Mahanarva fimbriolata which are meroistic telotrophic with nurse cells and oocytes located in the tropharium. SEM revealed paired ovaries located dorsolaterally around the intestine, and oocytes exhibiting shapes ranging from round (less developed) to elliptic (more developed), suggesting a simultaneous, although, asynchronous development. Based on histological data we classified the oocytes in stages from I to V. Stage I oocytes exhibit follicular epithelium with cubic and/or prismatic cells, fine cytoplasmic granules. Stage II oocytes present intercellular spaces in the follicular epithelium due to the incorporation of yolk elements from the hemolymph. Small granules are present in the periphery of oocytes while larger granules are observed in the center. Stage III oocytes are larger and intercellular spaces in the follicular epithelium are evident, as well as the interface between follicular epithelium and oocyte. Yolk granules of different sizes are present in the cytoplasm. During this stage, chorion deposition initiates. Stage IV oocytes exhibit squamous follicular cells and larger intercellular spaces when compared to those observed in the previous stage. The oocyte cytoplasm present granular and viscous yolk, the latter is the result of the breakdown of granules. Stage V oocytes exhibit a follicular epithelium almost completely degenerated, smaller quantities of granular yolk and large amounts of viscous yolk. Based on our findings we established the sequence of yolk deposition in M. fimbriolata oocyte as follows: proteins and lipids, which are first produced by endogenous processes in stages I and II oocytes. Exogenous incorporation begins in stage III. In stages I and II oocytes, lipids are also produced by follicular epithelial cells. The third element to be deposited is polysaccharides, mainly found as complexes. Therefore, the yolk present in the oocytes of this species consists of glycolipoproteins. Molecular weights of proteins present in M. fimbriolata oocytes ranged from 10 to 92 KDa, differently from vitellogenin, the most common protein present in insect oocytes, weighing approximately 180 KDa. (c) 2006 Elsevier Ltd. All rights reserved.
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C-banding and silver-staining techniques were used to examine pupal ovaries of Aedes aegypti from Sao Jose do Rio Preto (Brazil). Silver staining in ovary cystocytes showed two basic patterns relative to the nucleolar morphology: viz (1) a single, compact small body; and (2) multiple bodies encompassing large nuclear areas. These two types of cystocytes were present in the ratio of 7:1, which is the same as the number of nurse cells and oocytes, respectively, in each follicle. This suggests the possibility of eventually using such a nucleolar morphological difference to recognize both cell types in developmental stages before emergence. Silver nitrate staining in metaphase chromosomes revealed centromeric bands on all six chromosomes. The C-banding pattern in metaphase chromosomes showed an intercalary band in one of the X arms, as described previously in other populations. In ovary cystocytes (pachytene stage) this C-positive band seemed to consist of two chromomeres. Phase contrast microscopy showed that the nucleolus was associated with the distal chromomere of this intercalary C-band, indicating that the nucleolus organizer region was located in that part of the heterochromatic band.
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In Neoponera villosa ants, we found ovaries of the polytrophic meroistic type which is characterized by the presence of nurse cells forming together with the oocyte, the so-called follicles. The nurse cells have the primary function of supplying the oocyte with RNA, but they contribute to the supply of other elements such as glycogen. With the objetive of detecting the presence of this substance in the ovarioles of workers and queens of N.villosa ante the ovaries were removed and processed according to electron microscopy technic for glycogen detection. Glycogen is a common element in insect oocytes and is abundantly distributed in the cytoplasm of N.villosa workers and queens. However, in ovarian follicles it can only be detected at stages ET and lit of development. Glycogen synthesis probably occurs predominantly in nurse cells which transfer it into the oocyte through the nourish pore. This process requires high energy expenditure that justify the large numbers of mitochondria associated with glycogen in the nurse cell cytoplasm. The amount of glycogen in the nurse cells of queens is slightly greater than workers.
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In Neoponera villosa ants, we found ovaries of the polytrophic meroistic type which is characterized by the presence of nurse cells forming together with the oocyte, the so-called follicles. The nurse cells have the primary function of supplying the oocyte with RNA, but they contribute to the supply of other elements such as glycogen. With the objetive of detecting the presence of this substance in the ovarioles of workers and queens of N. viillosa ants the ovaries were removed and processed according to electron microscopy technic for glycogen detection. Glycogen is a common element in insect oocytes and is abundantly distributed in the cytoplasm of N. villosa workers and queens. However, in ovarian follicles it can only be detected at stages II and III of development. Glycogen synthesis probably occurs predominantly in nurse cells which transfer it into the oocyte through the nourish pore. This process requires high energy expenditure that justify the large numbers of mitochondria associated with glycogen in the nurse cell cytoplasm. The amount of glycogen in the nurse cells of queens is slightly greater than workers.
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Elements of oocyte of Neoponera villosa ants (workers and queen) were analyzed histochemically and ultrastructurally. It was observed that lipids are the first element to be deposited. They appear in oocytes of all stages. Lipids probably arose in the younger oocytes (stages I and II) from mitochondria of their own cytoplasm and from the nurse cells as well. In mature oocytes (stage III) the cells of the follicular epithelium appears with droplets of lipids in their cytoplasm showing that besides the other sites, this epithelium can also be active in lipid synthesis.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC
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The effects of the active sulphoxide metabolite of the fasciolicide triclabendazole (Fasinex, Ciba-Geigy) on the vitelline cells of Fusciola hepatica were determined in vitro by transmission electron microscopy using both intact flukes and tissue-slice material. At a triclabendazole concentration of 15 mu g/ml the vitelline cells of intact flukes showed ultrastructural changes only after prolonged incubation periods (12-24 h). The changes observed were a swelling of the granular endoplasmic reticulum (GER) cisternae with decreased ribosomal covering in the intermediate-type cells and condensation of chromatin and disappearance of the nucleolus in the nucleus of the stem cell. Similar changes were evident more quickly (by 6 h) in whole flukes treated at the higher concentration of 50 mu g/ml. The shell globule clusters were loosely packed in the intermediate type-2 cells, and the number of intermediate type-1 cells declined with more prolonged incubation. Disruption of the nurse-cell cytoplasm was also observed from 12 h onwards. After only 6 h incubation of tissue-slice material at 50 mu g/ml, intermediate type-1 cells were absent, shell globule clusters in mature cells were loosely packed and the nurses cell cytoplasm was badly disrupted. By 12 h the vitelline cells were vacuolated and grossly abnormal. The results are discussed in relation to postulated actions of triclabendazole against the microtubule component of the cytoskeleton and against protein synthesis in the fluke.
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Blending Art and Science in Nurse Education: The Benefits and Impact of Creative Partnerships
This paper presents the benefits of an innovative education partnership between lecturers from the School of Nursing and Midwifery, Queens University Belfast and Arts Care, a unique Arts and Health Charity in Northern Ireland, to engage nursing students in life sciences
Nursing and Midwifery students often struggle to engage with life science modules because they lack confidence in their ability to study science.This project was funded by a Teaching Innovation Award from the School of Nursing and Midwifery, Queens University Belfast, to explore creative ways of engaging year one undergraduate nursing students in learning anatomy and physiology. The project was facilitated through collaboration between Teaching staff from the School of Nursing and Midwifery and Arts Care, Northern Ireland. This unique Arts and Health Charity believes in the benefits of creativity to well being.
RESEARCH OBJECTIVE(S)
To explore creative ways of engaging year one undergraduate nursing students in learning anatomy and physiology.
METHODS AND METHODLOGY
Students participated in a series of workshops designed to explore the cells, tissues and organs of the human body through the medium of felt. Facilitated by an Arts Care artist, and following self-directed preparation, students discussed and translated their learning of the cells, tissues and organs of the human body into striking felt images. During the project students kept a reflective journal of their experience to document how participation in the project enhanced their learning and professional development
RESULTS
Creativity transformed and brought to life the students learning of the cells, tissues and organs of the human body.
The project culminated in the exhibition of a unique body of artwork which has been exhibited across Northern Ireland in hospitals and galleries and viewed by fellow students, teaching staff, nurses from practice, artists, friends, family and members of the public.
CONCLUSION
The impact of creativity learning strategies in nurse education should be further explored.
REFERENCES
Bennett, M and Rogers, K.MA. (2014) First impressions matter: an active, innovative and engaging method to recruit student volunteers for a pedagogic project. Reflections, Available online at: QUB, Centre for Educational Development / Publications / Reflections Newsletter, Issue 18, June 2014.
Chickering,A.W. and Gamson,Z.F. (1987) Seven principles for good practice in undergraduate education The American Association for Higher Education Bulletin, March. http://www.aahea.org/aahea/articles/sevenprinciples1987.htm, accessed 8th August 2014
Fell, P., Borland, G., Lynne, V. (2012) Lab versus lectures: can lab based practical sessions improve nursing students’ learning of bioscience? Health and Social Care Education 3:1, 33-38
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The ultrastructure of digestive cells of newly emerged, nurse and forager worker bees is described. Newly emerged bees have the endoplasmic reticulum characteristically in whorls and stacks as well as in parallel arrays of smooth endoplasmic reticulum. Nurse bees have spherits, autophagic vacuoles, lysosomes and multivesicular bodies. Forager bees have many cells with disorganized cytoplasm containing vacuoles, lamellated bodies, lipid inclusions, microbodies and intranuclear crystalloid inclusions. The basal cell region stays essentially unchanged. The changes observed are discussed in relation to previous observations on other insect species.