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Ultrastructure of secretory and senescence phase in colleters of Bathysa gymnocarpa and B. stipulata (Rubiaceae)
Miguel, Emilio de Castro;Klein, Denise Espellet;Oliveira, Marco Antonio de;Cunha, Maura da;
Brazilian Journal of Botany , 2010, DOI: 10.1590/S0100-84042010000300006
Abstract: (ultrastructure of secretory and senescence phase in colleters of bathysa gymnocarpa and b. stipulata (rubiaceae)). colleters are secretory structures formed by a parenchymatic axis with vascular bundles, bound by a layer of secretory palisade-like epidermis. some studies regarding the structure of colleters have focused on secretory cells structure, but not distinguished the secretory and senescent phases. generally, in mucilage-secreting cells such as colleters, the endoplasmic reticulum and golgi apparatus are involved in secretion production and transport. in these study, colleters structure of bathysa gymnocarpa k. schum. and b. stipulata (vell.) c. presl. (rubiaceae) were determined in two phases: a secretory phase and a senescence one. samples were collected and processed by usual light and electron microscopy techniques. studied colleters are constituted by an epidermal palisade layer and a central axis formed by parenchymatic cells with rare vascular traces. during the secretory phase, epidermal cells presented a dense cytoplasm, small vacuoles, enhanced rough and smooth endoplasmic reticulum, and a golgi apparatus close to large vesicles. during the senescence phase epidermal cells presented a disorganized membrane system. no intact organelles or vesicles were observed. the outer cell wall exhibited similar layers to that observed during the secretory phase. the senescent phase is easily defined by the morphology of the colleters, but not well defined at subcellular level. our research suggests that programmed cell death starts on secretory phase. however, more evidences are needed to evaluate the phenomena.
The Ultrastructure Characteristics of Secretory Cavities Associated with the Secretory Products of Ginkgo biloba  [PDF]
Fangren Peng, Hongyan Guo, Mingzhuo Hao, Juan Guo, Yuzhen Yang, Pengpeng Tan
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.31010
Abstract: The origin, development and ultrastructure of secretory cavities in leaf of Ginkgo biloba and its relation to the secretory products were studied by optical and electron microscope. The results indicated that the formation pattern of the secretory cavities was schizo-lysigenous in nature. First, some original central secretory cells in the center of secretory cavities expanded, dissolved then moved aside schizogeneously forming an intercellular space. Later the central and peripheral secretory cells continued to dissolve making the intercellular space larger. This process continued until the central secretory cells degenerated, autolyzed and separated off into cavities. It has been assumed that the secretory products in the secretory cavities of Ginkgo biloba were synthesized mainly in the plastids and the endoplasmic reticulum (ER). However it was our observation that the Mitochondrion, Golgi Body and Cytoplasm were also involved in the synthesis and translocation of the secretions. After synthesized in ER and plastids, the secretory products approached the plasmalemma and fused their membranes with the latter in the form of samll vesicles, and then was eliminated to the spaces between the plasmalemma and the wall. At last the secretory products percolated through the wall that faded into an even looser mesh of fibrillar material toward the cavity.
Nuclear DNA content and ultrastructure of secretory cells of Vicia faba L. stigma
Bogdan Wróbel,El?bieta Bednarska
Acta Societatis Botanicorum Poloniae , 1994, DOI: 10.5586/asbp.1994.018
Abstract: The object of study was the level of nuclear DNA and the ultrastructural transformations in the secretory cells of the stigma in Vicia faba L. It has been found that the stigmal cells which are active in biogenesis and exudate secretion are diploid cells whose differentiation starts from 2C DNA level. The presence of a population of nuclei with an amount DNA of about 2.5 C suggests that the metabolic activity of those cells may be regulated through supplementary incomplete replication. The ultrastructural transformations of secretory cells point to three stages of biogenesis and secretion of exudate. Stage I, before the start of the cell's secretory functions, is characterized by the development of the protein synthesizing apparatus and the activity of dictyosomes. In development stage II vesicular electron-transparent exudate is secreted. Stage III of exudate biogenesis is production of lipids. They form mainly in the plastids and are secreted with the involvement of the cell's vacuolar system.
Secretory Structures in Flourensia campestris and F. oolepis: Ultrastructure, Distribution, and (-)-Hamanasic Acid A Secretion  [PDF]
Mariana P. Silva, Graciela M. Tourn, Daniela López, Beatriz G. Galati, Leonardo A. Piazza, Gabriela Zarlavsky, Juan J. Cantero, Ana L. Scopel
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.67100
Abstract: In this work, the localization, density, morphology and ultrastructure of secretory structures in aerial organs of Flourensia campestris (FC) and F. oolepis (FO) (Asteraceae) by means of a combination of light, fluorescence, transmission (TEM) and scanning electron microscopy (SEM) were examined. The possible role of secretory structures in the production and secretion of the phytotoxic sesquiterpene (-)-hamanasic acid A ((-)HAA) in both species was also assessed. Capitate glandular trichomes were found in all reproductive organs of FC and FO, and were being reported for the first time. These glandular trichomes, typically associated to edges and veins, were of the same type as those already described for vegetative organs, and were abundant in involucral bracts and corolla of tubulose and ligulate flowers. Their density in reproductive organs of both species was similar (ca. 30/mm2) and lower than that found in leaves (ca. 100/mm2) and stems (ca. 160/mm2 in FC, and up to 650/mm2 in FO). Glandular trichomes in vegetative organs followed a species-specific pattern of distribution. TEM and SEM observations suggest that each species differs in the way in which secretory materials are released to the outside: through cracks or pores in FC, or through a loose cuticle in FO. Similar inspections of the secretory ducts revealed lipophilic vacuoles localized in subepithelial and epithelial cells, in which secretions accumulated before being transferred to the duct. The presence of wall ingrowths in subepithelial cells suggests that granulocrine secretion operates in these species. Secretory ducts varied in density and diameter among the organs in both species, with the combination being maximal in woody stems. (-)HAA was only detected in surface secreted resins of both species, and its concentration (2D-TLC, GC-FID) was intimately associated with the distribution and density of glandular trichomes in each organ (capitula, leaves, and stems with primary or secondary growth). In addition, no (-)HAA was detected internally in the resins collected from secretory ducts. The composition of these resins showed distinctive profiles for FC and FO, and only four from ca. 30 compounds detected (GC/MS) were shared by both species. In addition to the elucidation of ultrastructural traits, distribution and density of secretory structures in aerial organs of FC and
Anatomy and ultrastructure of spur nectary of Gymnadenia conopsea (L.) Orchidaceae
Ma?gorzata Stpiczyńska,Janusz Matusiewicz
Acta Societatis Botanicorum Poloniae , 2001, DOI: 10.5586/asbp.2001.034
Abstract: The anatomy and the ultrastructure of spur nectaries of Cymnadenia conopsea at different developmental stages were investigated. The secretory epidermis surrounded the inside of spur and formed many unicellular papillae, which significantly enlarged the secretory surface. At the activity stage the epidermal cells contained characteristic plastids with well developed intraplastidal membrane system and numerous osmiophillic globules. The contact of plastids and endoplasmic reticulum indicates a possibility of the involvement of these structures in the secretory processes. The cell wall and the cuticle did not form a barrier for the secreted nectar and no pores or cracks were visible in the cuticle covering secretory papillae.
Visual categorization and the parietal cortex  [PDF]
Sruthi K. Swaminathan,David J. Freedman
Frontiers in Integrative Neuroscience , 2012, DOI: 10.3389/fnint.2012.00018
Abstract: The primate brain is adept at rapidly grouping items and events into functional classes, or categories, in order to recognize the significance of stimuli and guide behavior. Higher cognitive functions have traditionally been considered the domain of frontal areas. However, increasing evidence suggests that parietal cortex is also involved in categorical and associative processes. Previous work showed that the parietal cortex is highly involved in spatial processing, attention, and saccadic eye movement planning, and more recent studies have found decision-making signals in lateral intraparietal area (LIP). We recently found that a subdivision of parietal cortex, LIP, reflects learned categories for multiple types of visual stimuli. Additionally, a comparison of categorization signals in parietal and frontal areas found stronger and earlier categorization signals in parietal cortex arguing that, in trained animals, parietal abstract association or category signals are unlikely to arise via feedback from prefrontal cortex (PFC).
The parietal association cortex of the rat
TORREALBA,FERNANDO; VALDéS,JOSé LUIS;
Biological Research , 2008, DOI: 10.4067/S0716-97602008000400002
Abstract: spatial cognition is a complex higher function in mammals and is involved in a variety of tasks that can be explored in the laboratory. in this review we will discuss the role of the posterior parietal/anteromedial cortex of rodents, also known as the parietal association cortex, and the hippocampal formation in spatial navigation. we will also discuss other higher associational functions of the posterior parietal/anteromedial cortex as they relate to dr. pinto-hamuy's contribution to understanding behavioral functions.
The parietal association cortex of the rat  [cached]
FERNANDO TORREALBA,JOSé LUIS VALDéS
Biological Research , 2008,
Abstract: Spatial cognition is a complex higher function in mammals and is involved in a variety of tasks that can be explored in the laboratory. In this review we will discuss the role of the posterior parietal/anteromedial cortex of rodents, also known as the parietal association cortex, and the hippocampal formation in spatial navigation. We will also discuss other higher associational functions of the posterior parietal/anteromedial cortex as they relate to Dr. Pinto-Hamuy's contribution to understanding behavioral functions.
Y
广州汉族人群DYS19、DYS389Ⅰ/Ⅱ、DYS390多态性及其单体型 Y-DNA STRs Polymorphisms and Haplotypes in Guangzhou Han Population

Ladder,
唐双柏
,郭景元,刘超,梁赏猷,王穗保TANG Shuang-bo,GUO Jing-yuan,LIU Chao,LIANG Shang-you,WANG Sui-bao

遗传 , 2000,
Abstract: In order to apply a set of useful and high polymorphic YSTRs in forensic practice and genetic analysis,we performed a population genetic study from Chinese.The allele distributions of the systems DYS19、DYS389Ⅰ/Ⅱ、and DYS390 were investigated in sample of 111 unrelated males from the area of Guangzhou, China.PCR products were detected using polyacrylamide gel electrophoresis and silver staining.5、4、5、5 alleles were observed in locus DYS19、DYS389Ⅰ、DYS389Ⅱ、DYS390 respectively.Different allele frequency distributions were observed when compared to other population.Haplotype frequency date of 72 different types were obtained.
Ultrastructure of the midgut endocrine cells in Melipona quadrifasciata anthidioides (Hymenoptera, Apidae)
Neves, C. A.;Gitirana, L. B.;Serr?o, J. E.;
Brazilian Journal of Biology , 2003, DOI: 10.1590/S1519-69842003000400015
Abstract: in this study we describe the ultrastructure of the endocrine cells observed in the midgut of m. quadrifasciata anthidioides. this bee has two types of endocrine cells, which are numerous on the posterior midgut region. cells of the closed type are smaller and have irregular secretory granules with lower electrondensity than those of the open cell type. the open cell type has elongated mitochondria mainly on the basal area, where most of the secretory granules are also found. besides the secretion granules and mitochondria, endocrine cells in this species have well-developed autophagic vacuoles and golgi complex elements.
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