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GEITLERINEMA SPECIES (OSCILLATORIALES, CYANOBACTERIA) REVEALED BY CELLULAR MORPHOLOGY, ULTRASTRUCTURE, AND DNA SEQUENCING

BITTENCOURT-OLIVEIRA, Maria do Carmo; MOURA, Ariadne do Nascimento; OLIVEIRA, Mariana Cabral de; MASSOLA JR., Nelson Sidnei
Fonte: WILEY-BLACKWELL PUBLISHING, INC Publicador: WILEY-BLACKWELL PUBLISHING, INC
Tipo: Artigo de Revista Científica
ENG
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Geitlerinema amphibium (C. Agardh ex Gomont) Anagn. and G. unigranulatum (Rama N. Singh) Komarek et M. T. P. Azevedo are morphologically close species with characteristics frequently overlapping. Ten strains of Geitlerinema (six of G. amphibium and four of G. unigranulatum) were analyzed by DNA sequencing and transmission electronic and optical microscopy. Among the investigated strains, the two species were not separated with respect to cellular dimensions, and cellular width was the most varying characteristic. The number and localization of granules, as well as other ultrastructural characteristics, did not provide a means to discriminate between the two species. The two species were not separated either by geography or environment. These results were further corroborated by the analysis of the cpcB-cpcA intergenic spacer (PC-IGS) sequences. Given the fact that morphology is very uniform, plus the coexistence of these populations in the same habitat, it would be nearly impossible to distinguish between them in nature. On the other hand, two of the analyzed strains were distinct from all others based on the PC-IGS sequences, in spite of their morphological similarity. PC-IGS sequences indicate that these two strains could be a different species of Geitlerinema. Using morphology...

Glandular trichomes on aerial and underground organs in Chrysolaena species (Vernonieae - Asteraceae): Structure, ultrastructure and chemical composition

Gloria, Beatriz Appezzato da; Costa, Fernando Batista da; Silva, Vanessa Cristina da; Neto, Leonardo Gobbo; Rehder, Vera Lúcia Garcia; Hayashi, Adriana Hissae
Fonte: ELSEVIER GMBH, URBAN & FISCHER VERLAG; JENA Publicador: ELSEVIER GMBH, URBAN & FISCHER VERLAG; JENA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Although the occurrence of glandular trichomes is frequently reported for aerial vegetative organs, many questions still remain opened about the presence of such trichomes in underground systems. Here, we present, for the first time, a comparative study concerning the structure, ultrastructure and chemical aspects of both, the aerial and underground glandular trichomes of two different Chrysolaena species, C obovata and C platensis. Glandular trichomes (GTs) were examined using LM, SEM, and TEM and also analyzed by GC-MS and HPLC coupled to UV/DAD and HR-ESI-MS (HPLC-UV-MS). In both aerial (leaf and bud) and underground (rhizophore) organs, the GTs are multicellular, biseriate and formed by five pairs of cells: a pair of support cells, a pair of basal cells, and three pairs of secreting cells. These secreting cells have, at the beginning of secretory process, abundance of smooth ER. The same classes of secondary metabolites are biosynthesized and stored in both aerial and underground GTs of C platensis and C obovata. These GTs from aerial and underground organs have similar cellular and sub-cellular anatomy, however the belowground trichomes show a higher diversity of compounds when compared to those from the leaves. We also demonstrate by means of HPLC-UV-DAD that the sesquiterpene lactones are located inside the trichomes and that hirsutinolides are not artifacts. (C) 2012 Elsevier GmbH. All rights reserved.; Sao Paulo Research Foundation - FAPESP [06/51370-9]; Sao Paulo Research Foundation (FAPESP); National Council for Scientific and Technological Development - CNPq [470750/2006-5]; National Council for Scientific and Technological Development (CNPq)

Ultraestrutura e expressão das enzimas: citocromo P450 aromatase e citocromo P450c17 (17-α-hidroxilase/17,20-liase) nas diferentes fases do desenvolvimento da via espermática e espermatogênese em cutia (Dasyprocta sp.) criada em cativeiro; Ultrastructure and expression of enzymes: cytochrome P450 aromatase and cytochrome P450c17 (17-α-hydroxylase/17,20-lyase) in different developmental stages of spermatogenesis and excurrent canals in agouti (Dasyprocta sp.) kept in captivity

Arroyo, Maria Angélica Machado
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/07/2013 PT
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Espécies silvestres com grande potencial zootécnico devem ser exploradas de forma racional a fim de se evitar a extinção das mesmas. Assim se dá a importância de pesquisas voltadas à reprodução daquelas criadas em cativeiro, como a cutia (Dasyprocta sp.). Este animal é um mamífero e roedor vivente, em sua maioria, na Caatinga brasileira. A ultraestrutura é a base para determinar os estágios celulares e, assim, facilitar as comparações dos processos entre cutias e roedores silvestres ou outros mamíferos. As enzimas P450 aromatase e P450c17 são responsáveis pela regulagem da produção de estrógenos e andrógenos, respectivamente. Considerando a hipótese de que o comportamento de expressão das enzimas do complexo citocromo P540 permanece o mesmo no testículo e na via espermática de cutias durante as fases de desenvolvimento sexual, objetivou-se observar a atuação das enzimas P450 aromatase e P450c17 (17-α-hidroxilase/17,20-liase) nas diferentes fases do desenvolvimento sexual, detalhar a ultraestrutura dos componentes desta via e constatar o desenvolvimento do processo espermatogênico. Segmentos do ducto deferente, epidídimo e testículo de 28 cutias machos em diferentes idades (um dia, 2-14 meses) foram fixados em paraformoldeído e glutaraldeído. O material foi coletado no Centro de Multiplicação da Universidade Federal Rural do Semiárido...

Spermatozoon ultrastructure and sperm cryopreservation of the Brazilian dry season spawner fish pirapitinga, Brycon nattereri

Viveiros, Ana T. M.; Maria, Alexandre N.; Amaral, Thiciana B.; Orfao, Laura H.; Isau, Ziara A.; Verissimo-Silveira, Rosicleire
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica Formato: 546-555
ENG
Relevância na Pesquisa
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The aims of this study were to describe the fresh spermatozoon ultrastructure using scanning and transmission electron microscopy and to improve the sperm cryopreservation methodology for the freshwater fish pirapitinga Brycon nattereri. Extenders (BTS (TM) and NaCl), straw volumes (0.5 and 4.0 mL), thawing temperatures (30 and 60 degrees C) and activating agents (0.29% NaCl and 1% NaHCO3) were tested. Methylglycol was used as a cryoprotectant agent and sperm was frozen in nitrogen vapour (dry-shipper). Post-thawed sperm motility rate, motility quality (score 0=no movement; 5=rapidly swimming spermatozoa), duration of motility and spermatozoon morphology were evaluated. Fresh spermatozoon was 35.06 mu m long, the head was ovoid (2.00 x 1.22 mu m) with no acrosome, the midpiece was 2.15 mu m long and the flagellum was 30.90 mu m long with the typical 9+2 axoneme arrangement. Post-thawed sperm motility rate (7079% motile sperm), motility quality (score 3.1-3.7) and morphology (9.311.6% abnormal spermatozoa) were not affected by any of the parameters tested. The duration of sperm motility was longer when triggered in 1% NaHCO3 (3921031 s) compared with 0.29% NaCl (144338 s). Brycon nattereri sperm cryopreserved under the conditions described above yields over 70% motility and should last long enough to fertilize oocytes...

Dendroid colleters on vegetative and reproductive apices in Alibertia sessilis (Rubiaceae) differ in ultrastructure and secretion

Machado, Silvia Rodrigues; Barreiro, Daniela Pacheco; Rocha, Joecildo Francisco; Rodrigues, Tatiane Maria
Fonte: Elsevier Gmbh, Urban & Fischer Verlag Publicador: Elsevier Gmbh, Urban & Fischer Verlag
Tipo: Artigo de Revista Científica Formato: 868-877
ENG
Relevância na Pesquisa
36.65%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 08/55434-7; Processo FAPESP: 02/09369-2; Processo FAPESP: 03/11747-8; In this work we compare the structure and secretion of dendroid colleters on stipules, bracts and sepals of Alibertia sessilis, a non-nodulate Rubiaceae species from Brazilian cerrado, with notes on the plant phenology. Samples were processed according to usual methods for anatomy, histochemistry and ultrastructure. Colleters are conical and constituted by a central axis of elongated parenchyma cells from which radiate numerous epidermal cells. Epidermal cells are cylindrical on the vegetative apex and digitiform or bulbous on reproductive apex. Both colleters produce hydrophilic and lipophilic compounds. on the vegetative apex, epidermal cells present numerous well-developed Golgi bodies associated with a network of smooth endoplasmatic reticulum (SER), scarce oil bodies and profiles of rough endoplasmatic reticulum (RER), indicating the involvement of these glands in the production of mainly polysaccharides in addition to protein and lipids. Differently, epidermal cells on bracts and sepals present abundant and prominent oil drops...

Spermatozoa ultrastructure in Sciaenidae and Polynemidae (Teleostei : Perciformes) with some consideration on Percoidei spermatozoa ultrastructure

Gusmao-Pompiani, P.; Oliveira, C.; Quagio-Grassiotto, I
Fonte: Churchill Livingstone Publicador: Churchill Livingstone
Tipo: Artigo de Revista Científica Formato: 177-191
ENG
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Spermatozoa ultrastructure was studied in five marines (Paralonchurus brasiliensis, Larimus breviceps, Cynoscion striatus, Micropogonias furnieri, Menticirrhus americanus, Umbrina coroides, Stellifer rastrifer), and one freshwater (Plagioscion squamosissimus) species of Sciaenidae and one species of Polynemidae (Polydactylus virginicus). The investigation revealed that, in all species, spermatozoa display a round head, a nucleus containing highly condensed, filamentous chromatin clusters, no acrosome, a short midpiece with a short cytoplasmic channel, and a flagellum showing the classic axoneme structure (9 + 2) and short irregular lateral fins. In Sciaenidae, the spermatozoa are type II, the flagellar axis is parallel to the nucleus, the lateral nuclear fossa is double arched, the centriolar complex is outside the nuclear fossa, the proximal centriole is anterior and perpendicular to the distal centriole, and no more than ten spherical (marine species) or elongate (freshwater species) mitochondria are observed. Polynemidae spermatozoa are of the intermediate type with the flagellar axis eccentric to the hemi-arc-shaped nucleus, and exhibit no nuclear fossa, the centriolar complex close to the upper nuclear end, the proximal centriole lateral and oblique to the distal centriole...

Spermatozoal ultrastructure in three species of the genus Uca Leach, 1814 (Crustacea, Brachyura, Ocypodidae)

Benetti, A. S.; Santos, D. C.; Negreiros-Fransozo, M. L.; Scelzo, M. A.
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 337-343
ENG
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Morphological aspects of spermatozoa in marine animals have been used in recent decades as phylogenetic criteria (spermiotaxonomy). This paper presents ultrastructural descriptions of the spermatozoa from Uca maracoani, U. thayeri, and U. vocator. A small portion of the vas deferens of each species was examined under the transmission and scanning electron microscopy. The ultrastructural analysis showed that each spermatophore consists of a varying number of spermatozoa embedded in a dense fibrillar matrix surrounded by a membrane. The spermatozoa of U. maracoani, U. thayeri, and U. vocator are typical of brachyurans. The Voluminous acrosome is characterized by three different layers. The postero-lateral surface of the acrosome is cupped by the reduced cytoplasm, and the anterior surface is covered by the operculum. The perforatorium consists of coiled, helicoidal membranous tubules and is continuous with the cytoplasm. The nucleus is composed by uncondensed chromatin and presents several lateral arms distributed over the entire equatorial plane of the cell. The presence of the apical button is a well defined character among all species of the genus Uca, but in U. thayeri it was not observed. The accessory opercular ring can be found in the three studied species...

Giardia agilis: Ultrastructure of the Trophozoites in the Frog Intestine

Sogayar, Maria Inês L; Gregório, Elisa Aparecida
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: 357-361
ENG
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Intestine samples of Bufo sp. tadpoles with parasitism confirmed for Giardia agilis were studied by transmission electron microscopy. The G. agilis trophozoites were long and thin. The plasma membrane was sometimes undulated and the cytoplasm, adjacent to the dorsal and ventral regions, showed numerous vacuoles. The two nuclei presented prominent nucleoli. The cytoplasm was electron-dense with free ribosomes, glycogen and rough endoplasmic reticulum-like structures. Polyhedral inclusions were observed in the cytoplasm and outside the protozoan; some of these inclusions exhibited membrane disruption. The flagella ultrastructure is typical, with the caudal pair accompanied by the funis. Next to the anterior pair, osmiophilic material was noticed. The ventro-lateral flange was short and thick, supported by the marginal plates that penetrated into its distal extremity; only its distal portion had adjacent osmiophilic filament. The G. agilis trophozoites showed the general subcellular feature of the genus. However, the ventro-lateral flange ultrastructure was an intermediate type between G. muris and G. duodenalis.

Ultrastructure of last larval instar fat body cells of Pachycondyla (= Neoponera) villosa (Formicidae : Ponerinae): cytochemical and chemical analysis

Zara, F. J.; Caetano, F. H.; Cabrera, ACG; Jaffe, K.
Fonte: Brill Academic Publishers Publicador: Brill Academic Publishers
Tipo: Artigo de Revista Científica Formato: 1-16
ENG
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The ultrastructure of the fat body cells (trophocytes) of the last larval instar of Pachycondyla (= Neoponera) villosa is presented. The cytoplasm is restricted to the cell periphery and to the smaller strips among the vacuoles, protein granules, lipid droplets, and around the nucleus. Cytochemically, the presence of basic amino acids in the protein granules and in the nuclei was observed by using the ethanolic phosphotungstic acid technique (EPTA). The lipid droplets stained for unsaturated lipids. This result was further confirmed by gas chromatography and mass spectrometry, where the unsaturated fatty acids were identified as oleic and linoleic acids together with saturated fatty acids such as palmitic and stearic acid. Carbohydrates (glycogen) were also detected in the fat body. The glycogen is present as beta particles distributed among the lipid droplets and sometimes attached to them.

Ultrastructure of spermatogenesis in the white-lined broad-nosed bat, Platyrrhinus lineatus (Chiroptera: Phyllostomidae)

Beguelini, Mateus R.; Puga, Cintia C. I.; Taboga, Sebastiao R.; Morielle-Versute, Eliana
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 586-599
ENG
Relevância na Pesquisa
36.78%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Spermatogenesis, the remarkable process of morphological and biochemical transformation and cell division of diploid stem cells into haploid elongated spermatozoa, is one of the most complex cell differentiations found in animals. This differentiation process has attracted extensive studies, not only because the process involves many radical changes in the cell shape and biochemistry, but also because the phases and steps of differentiation have provided a better basis for analyzing the seminiferous epithelium cycle. Thus, this study aimed to characterize ultrastructurally the spermatogenesis process in the bat Platyrrhinus lineatus in order to provide a basis for determining the stages of spermatogenesis and to facilitate comparisons of the process between bat species and other vertebrates. Based on ultrastructural characteristics three main types of spermatogonia could be accurately identified: A(d), A(p) and B; the differentiation of spermatids was clearly divided into 12 steps (steps 1-3: Golgi phase, steps 4-5: cap phase, steps 6-9: acrosomal phase and steps 10-12: maturation phase). The ultrastructure of spermatozoa...

Ultrastructure of Sorubim lima (Teleostei, Siluriformes, Pimelodidae) spermiogenesis

Quagio Grassiotto, Irani; Carvalho, E. D.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 629-633
ENG
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The spermiogenesis and the spermatozoon ultrastructure of Sorubim lima were studied. Our observations showed that early spermatids are round-shaped cells, have spherical nucleus with diffuse chromatin, small quantity of mitochondria and large amount of vesicles in the cytoplasm. During the differentiation process in the nucleus, chromatin compacts in a progressive and homogeneous way, and the flagellum is formed. In the cytoplasm the vesicles, that have double membranes, aggregate and fuse on the plasma membrane. The spermatozoa of 5. lima have no acrosome and show spherical nucleus with homogeneous and highly compacted chromatin, intermediary piece with mitochondria and double wall vesicles contiguous to the plasma membrane, as well as a flagellum formed by a basic axoneme (9 + 2).

Associação de ciclosporina e Heteropterys aphrodisiaca (no-de-cachorro) adminstrados a ratos wistar : estrutura, ultra-estrutura e morfometria testicular; Association of cyclosporine and Heteropterys aphrodisiaca (no-de-cachorro) administered to Wistar rats : testicular structure, ultrastructure and morphometry

Juliana Castro Monteiro
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/02/2007 PT
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TA ciclosporina A (CsA) possui potentes propriedades imunossupressivas e tem sido amplamente usada na terapia de transplantes de órgãos, aumentando as taxas de sobrevivência dos enxertos, e no tratamento de algumas doenças auto-imunes. Apesar de ser um importante medicamento, diversas reações colaterais são verificadas, entre elas a toxicidade testicular, levando à infertilidade masculina. Heteropterys aphrodisiaca é uma planta com indicações de estimulante e potente afrodisíaco, que aumenta o peso corporal e testicular e o volume das células de Leydig nos testículos de ratos adultos. Assim o efeito da associação dessas drogas foi estudado em ratos Wistar em idade reprodutiva, com avaliação da morfometria, estrutura e ultra-estrutura testicular. Foram utilizados 30 ratos divididos em 5 grupos: I- controle; II- tratamento com CsA; III- concomitante uso de CsA e H. aphrodisiaca; IV- pré-tratamento com H. aphrodisiaca por 30 dias, seguido de CsA por 26 dias; V- tratamento com H. aphrodisiaca. CsA foi administrada na dose de 15 mg/kg/dia e H. aphrodisiaca na dose de 0.5 ml de infusão preparada com 25g de raízes secas/100 ml água fervente. Os tratamentos foram administrados diariamente por gavagem, durante 56 dias. Aumento do peso corporal foi observado em todos os grupos...

Giardia agilis: Ultrastructure of the Trophozoites in the Frog Intestine

Sogayar,Maria Inês L; Gregório,Elisa Aparecida
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/1998 EN
Relevância na Pesquisa
36.78%
Intestine samples of Bufo sp. tadpoles with parasitism confirmed for Giardia agilis were studied by transmission electron microscopy. The G. agilis trophozoites were long and thin. The plasma membrane was sometimes undulated and the cytoplasm, adjacent to the dorsal and ventral regions, showed numerous vacuoles. The two nuclei presented prominent nucleoli. The cytoplasm was electron-dense with free ribosomes, glycogen and rough endoplasmic reticulum-like structures. Polyhedral inclusions were observed in the cytoplasm and outside the protozoan; some of these inclusions exhibited membrane disruption. The flagella ultrastructure is typical, with the caudal pair accompanied by the funis. Next to the anterior pair, osmiophilic material was noticed. The ventro-lateral flange was short and thick, supported by the marginal plates that penetrated into its distal extremity; only its distal portion had adjacent osmiophilic filament. The G. agilis trophozoites showed the general subcellular feature of the genus. However, the ventro-lateral flange ultrastructure was an intermediate type between G. muris and G. duodenalis.

Ultrastructure and chaetotaxy of sensory eeceptors in the cercaria of a species of Allopodocotyle Pritchard, 1966 (Digenea: Opecoelidae)

Bogéa,T; Caira,JN
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2001 EN
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36.93%
Previous investigations of sensory systems in opecoelid cercariae have focused on chaetotaxy and ultrastructure of sensory receptors. They revealed chaetotaxic patterns within family, genus, and species as well as different receptors. Chaetotaxic and ultrastructural observations have rarely been combined. We investigated the ultrastructure of cercarial sensory receptors in conjunction with chaetotaxy and neuromorphology in a species of Allopodocotyle. Cercariae were treated with acetylthiocholine iodide and silver nitrate, and some were processed for light, scanning (SEM), and transmission (TEM) electron microscopy. Five nerve regions were distinguished. Chaetotaxy was consistent with that of other opecoelids. Five types of receptors were distinguished with SEM. Types differed in number of cilium-like structures (one or more), length of cilium-like structure (short, moderately long, or long), presence or absence of a tegumentary collar, and length of tegumentary collar (low, moderately low, or very high). Internal ultrastructure of some types revealed unsheathed cilium-like structures, basal body, and thickened nerve collars. Possible subtegumentary and sheathed receptors are introduced. Some receptor types were site-specific. For example...

Phytohemagglutinin improves the development and ultrastructure of in vitro-cultured goat (Capra hircus) preantral follicles

Cunha,E.V.; Costa,J.J.N.; Rossi,R.O.D.S.; Silva,A.W.B.; Passos,J.R.S.; Portela,A.M.L.R.; Pereira,D.C.S.T.; Donato,M.A.M.; Campello,C.C.; Saraiva,M.V.A.; Peixoto,C.A.; Silva,J.R.V.; Santos,R.P.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2013 EN
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The objective this study was to determine the effect of phytohemagglutinin (PHA) on survival, growth and gene expression in caprine secondary follicles cultured in vitro. Secondary follicles (∼0.2 mm) were isolated from the cortex of caprine ovaries and cultured individually for 6 days in α-MEM+ supplemented with PHA (0, 1, 10, 50, 100, or 200 µg/mL). After 6 days of culture, follicle diameter and survival, antrum formation, ultrastructure and expression of mRNA for FSH receptors (FSH-R), proliferating cell nuclear antigen (PCNA), and neuronal nitric oxide synthase were determined. All treatments maintained follicular survival [α-MEM+ (94.59%); 1 µg/mL PHA (96.43%); 10 µg/mL PHA (84.85%); 50 µg/mL PHA (85.29%); 100 µg/mL PHA (88.57%), and 200 µg/mL PHA (87.50)], but the presence of 10 µg/mL PHA in the culture medium increased the antrum formation rate (21.21%) when compared with control (5.41%, P < 0.05) and ensured the maintenance of oocyte and granulosa cell ultrastructures after 6 days of culture. The expression of mRNA for FSH-R (2.7 ± 0.1) and PCNA (4.4 ± 0.2) was also significantly increased in follicles cultured with 10 µg/mL PHA in relation to those cultured in α-MEM+ (1.0 ± 0.1). In conclusion...

Ultrastructure of a Temperature-Sensitive Rod− Mutant of Bacillus subtilis

Cole, Roger M.; Popkin, Terry J.; Boylan, Robert J.; Mendelson, Neil H.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1970 EN
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Mutant 168ts-200B, resulting from nitrosoguanidine treatment of Bacillus subtilis 168 (trp− C2), exhibits a rod-to-sphere morphogenetic interconversion when the incubation temperature is 30 or 45 C, respectively. Ultrathin sections of rods grown at 30 C, after glutaraldehyde-osmium uranium-lead fixation and staining, show trilaminar cell walls with a well-developed underlying periplasm as in wild-type cells. However, the outer wall layer is irregular, and abnormal protrusions of wall material occur at the cross-walls. In contrast, cells growing at 45 C become rounded and are intersected randomly by irregular cross-walls which fail to split normally, resulting in large spherical masses. In these, the outer and inner wall layers and periplasm are lost, and the wall consists only of irregularly thickened and loosely organized middle layer. Wall ultrastructure is reversible in either direction as cell shape changes during temperature shifts. Mesosomes are rare and atypical at either temperature. It thus appears that cell wall ultrastructure is altered by the conditional (temperature-sensitive) mutation, and that loss of normal wall and submural organization is correlated with changes in cell size and shape as well as with inability to complete cell division. Preliminary studies after transformation of the mutant locus to another strain and growth at 45 C showed an increase in mucopeptide...

Contribuição ao conhecimento da anatomia, micromorfologia e ultraestrutura foliar de Amaranthaceae do Cerrado; Contribution to the knowledge of the anatomy, micromorphology and ultrastructure of the leaves of the Cerrado's Amaranthaceae

Suzane Margaret Fank-de-Carvalho
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/01/2011 PT
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36.87%
A família Amaranthaceae no sensu lato, incluindo Chenopodiaceae, é formada por cerca de 2.360 espécies, 145 delas encontradas no Brasil; 94 espécies subsistem em diversas fitofisionomias do Bioma Cerrado, 71 são endêmicas de diferentes regiões e biomas brasileiros e 27 aparecem em listas regionais de espécies ameaçadas de extinção. Visando contribuir para o conhecimento das espécies dessa família, foram estudados aspectos ecológicos, micromorfológicos, anatômicos e ultraestruturais de folhas de Amaranthaceae nativas do Brasil, com ênfase nos gêneros Alternanthera, Gomphrena, Froelichiella, Hebanthe e Pfaffia. As espécies nativas de regiões abertas de cerrado apresentam adaptações que favorecem a sobrevivência em condições adversas (seca e fogo), tais como raízes tuberosas ou lenhosas e xilopódios, hábito herbáceo e/ou subarbustivo, pilosidade densa nas porções aéreas, senescência de ramos aéreos durante as fases mais secas, dependência de fogo ou chuva para rebrotação e/ou floração, frutificação rápida seguida de dispersão anemocórica, epidermes com cutículas bem desenvolvidas e metabolismo fotossintético C4. O comportamento pirofítico das espécies favorece o estabelecimento pioneiro das mesmas...

Effect of a Brassinosteroid Analogue and High Temperature Stress on Leaf Ultrastructure of Lycopersicon Esculentum

Sam, O.; Núñez, M.; Ruiz Sánchez, Mª Carmen; Dell' Amico, José; Falcón, V.; Rosa, M. C. de la; Seoane, Javier
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
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The ultrastructure of tomato leaf disks treated with a biostimulator (0.01 mg dm–3 BB6, brassinosteroid analogue from Cuba), and subjected to high temperature (40 °C for 1.5 h) was studied. High temperature stress caused the appearance of granules in the nucleus, nucleolus and cytoplasm. In chloroplasts and in mitochondria the internal membrane system was disorganised and in chloroplasts some starch granules were detected. These symptoms were more marked in the cells treated with BB6. The influence of BB6 on the ultrastructure of leaf cells was apparent also before being subjected to heat stress.; The study was supported by a CSIC/CITMA (99CU0002) cooperation project and a CITMA (PNCT 013 05 008)project; Peer reviewed

Morphology and ultrastructure of the freshwater rotifer Brachionus bidentatus (Monogononta: Brachionidae) using scanning and transmission electron microscopy

Guerrero-Jiménez,Gerardo; Zavala-Padilla,Guadalupe; Silva-Briano,Marcelo; Rico-Martínez,Roberto
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2013 EN
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36.78%
The study of sexual reproductive behavior supported by ultrastructural evidence is important in rotifers to describe differences among potential cryptic species. In this research, the morphology of the rotifer Brachionus bidentatus is described at the ultrastructural level, using electronic microscopy, together with a brief description and discussion of its sexual reproductive behavior. The characteristics of the (a) male,(b) the female, (c) the sexual egg or cyst, (d) the partenogenic egg, (e) the no-fecundated sexual egg (male egg), and (f) the trophi, were described. Another part of this research is dedicated to the ultrastructure of the sex cells of the male rotifer B. bidentatus. Samples were obtained from La Punta pond in Cosio, Aguascalientes, Mexico (22°08’ N - 102°24’ W), and a culture was maintained in the laboratory. Fifty organisms, from different stages of the rotifer Brachionus bidentatus, were fixed in Formol at 4% and then prepared; besides, for the trophi, 25 female rotifer Brachionus bidentatus were prepared for observation in a JEOL 5900 LV scanning electronic microscope. In addition, for the observation of male sex cells, 500 males of Brachionus bidentatus were isolated, fixed and observed in a JEOL 1010 transmission microscope. Females of B. bidentatus in laboratory cultures had a lifespan of five days (mean±one SD=4.69±0.48; N=13)...

Ultrastructure of Oryza glumaepatula , a wild rice species endemic of tropical America

Sánchez,Ethel; Espinoza,Ana M
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2005 EN
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36.78%
Oryza glumaepatula is a perennial wild rice species,endemic to tropical America, previously known as the Latin American race of Oryza rufipogon .In Costa Rica, it is found in the northern region of the country, mainly in the wetland of the Medio Queso River, Los Chiles, Alajuela. It is diploid, of AA type genome and because of its genetic relatedness to cultivated rice it is included in the O.sativa complex. We describe the ultrastructure of leaf blade, spikelet, ligule and auricles. Special emphasis is given to those traits of major taxonomic value for O.glumaepatula and to those characters that distinguish this species from O. rufipogon and O. sativa . O. glumaepatula has a leaf blade covered with tombstone-shaped, oblong and spheroid epicuticular wax papillae. It has diamond-shaped stomata surrounded by spherical papillae, rows of zipper-like silica cells, bulky prickle trichomes of ca .40 m m in length and small hirsute trichomes of ca. 32 m m in length.The central vein is covered with large,globular papillae of ca. 146 m m in length,a characteristic that distinguishes this species from O.rufipogon and O.sativa. The border of the leaf blade exhibits a row of even-sized bulky prickle trichomes of ca .42.5 m m in length.Auricles have attenuated trichomes of ca .5.5 mm in length on the edges and small bicellular trichomes of 120 m m in length on the surface.The ligule has a large number of short attenuated trichomes on its surface of 100 m m in length.These latter two traits have important taxonomic value since they were found in O.glumaepatula but not found in O.sativa or in O.rufipogon . The spikelet has the typical morphology of the Oryza genus. Fertile lemmas have abundant spines...