scholarly journals ON A RETICULAR DERIVATIVE FROM GOLGI BODIES IN THE MERISTEM OF Anthoceros

1960 ◽  
Vol 8 (1) ◽  
pp. 221-231 ◽  
Author(s):  
Irene Manton
Keyword(s):  
Vegetative Cell ◽  
Developmental Stages ◽  
Early Stage ◽  
Smooth Endoplasmic Reticulum ◽  
Mitotic Division ◽  
Golgi Bodies ◽  
Spore Mother Cell ◽  
A Cell ◽  
Face View ◽  
Morphological Differences

Micrographs of dictyosomes in face view and in profile, together with serial sections representing both these planes, are reproduced from three sample cells at different developmental stages in the meristem of Anthoceros. The stages are: a vegetative cell at anaphase of a mitotic division, a vegetative cell in an early stage of postmitotic extension growth, and a young spore mother cell in the act of rounding up before the onset of meiosis. The observations suggest that proliferation of tubules from the edges of the dictyosomal cisternae into the cytoplasm is occurring with varying intensity and with slightly different morphological expression in all three cells. In all, the tubules are joined into a reticulum which exhibits local swellings at varying distances from the unfenestrated part of the subtending cisterna. A comparison is suggested between the observed reticulum and "smooth" endoplasmic reticulum of animals but it is not claimed that all the cytoplasmic tubules detectable in Anthoceros need have arisen in this way. Morphological differences discernible between tubules near their point of attachment to dictyosomes and others apparently involved in the formation of the new nuclear membrane at the end of a cell division could mean that more than one category of tube may exist in these cells. A plea is registered for restraint in the formulation of far reaching theories until more facts are available on unequivocal evidence.

scholarly journals N-acetyl-L-cysteine Improves the Developmental Competence of Bovine Oocytes and Embryos Cultured In Vitro by Attenuating Oxidative Damage and Apoptosis

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 860
Author(s):  
Wu-Sheng Sun ◽  
Hoon Jang ◽  
Mi-Ryung Park ◽  
Keon Bong Oh ◽  
Haesun Lee ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Early Stage ◽  
Developmental Competence ◽  
Beneficial Effects ◽  
Developmental Rates ◽  
A Cell ◽  
Bovine Oocytes ◽  
Dose Dependent

Oxidative stress has been suggested to negatively affect oocyte and embryo quality and developmental competence, resulting in failure to reach full term. In this study, we investigated the effect of N-acetyl-L-cysteine (NAC), a cell-permeating antioxidant, on developmental competence and the quality of oocytes and embryos upon supplementation (0.1–10 mM) in maturation and culture medium in vitro using slaughterhouse-derived oocytes and embryos. The results show that treating oocytes with 1.0 mM NAC for 8 h during in vitro maturation attenuated the intracellular reactive oxygen species (ROS) (p < 0.05) and upregulated intracellular glutathione levels (p < 0.01) in oocytes. Interestingly, we found that NAC affects early embryonic development, not only in a dose-dependent, but also in a stage-specific, manner. Significantly (p < 0.05) decreased cleavage rates (90.25% vs. 81.46%) were observed during the early stage (days 0–2), while significantly (p < 0.05) increased developmental rates (38.20% vs. 44.46%) were observed during the later stage (from day 3) of embryonic development. In particular, NAC supplementation decreased the proportion of apoptotic blastomeres significantly (p < 0.05), resulting in enhanced hatching capability and developmental rates during the in vitro culture of embryos. Taken together, our results suggest that NAC supplementation has beneficial effects on bovine oocytes and embryos through the prevention of apoptosis and the elimination of oxygen free radicals during maturation and culture in vitro.

Ultrastructure of the osphradium of the Tertiary relict snail, Campanile symbolicum Iredale (Mollusca, Streptoneura)

1992 ◽  
Vol 337 (1282) ◽  
pp. 457-469 ◽  
Keyword(s):  
Smooth Endoplasmic Reticulum ◽  
Sense Organ ◽  
Central Zone ◽  
Structural Data ◽  
Structural Features ◽  
Sensory Epithelium ◽  
Sensory Cells ◽  
Cell Type ◽  
Sensory Cilia ◽  
A Cell

The osphradium of Campanile symbolicum Iredale, 1917 is a gill-like, bipectinate sense organ, which is located at the left side of the mantle roof. The mass of the deeply clefted sensory epithelium of the leaflets is built up by sensory cells, which are provided with deeply invaginated aberrant cilia and large cytosomes containing pigment formations. In addition, many free nerve processes are present, bearing a single or few sensory cilia with accessory centrioles. Polyciliary cells are interspersed. A cell type with netlike or concentrically arranged smooth endoplasmic reticulum is commonly found near the central axis of the osphradium . The central zone of each leaflet includes nervous tissue and a complicated muscular grid, with pore cells and fibroblasts also present. Based on the fine-structural data the functional and ecological significance of the osphradium of Campanile symbolicum is discussed. The com bination of herbivory and a lamellar osphradium is rare among the Gastropoda, suggesting that the osphradium of Campanile might also be involved in reproductive biology. Many fine-structural features of the osphradium of Campanile symbolicum are unique among the gastropods and reflect the phylogenetic isolation of this relict snail. The net-like cell type, however, is probably homologous with the so-called Si4 cell in the rem aining caenogastropods, for which a largely different osphradial fine-structure is diagnostic. The affinities of Campanile symbolicum are probably closer to the Caenogastropoda than to the Allogastropoda and Euthyneura. With present knowledge it might be best classified near the base or even as the first clade within the Caenogastropoda.

scholarly journals Influence of Parenting Styles and Developmental Stages on Identity Formation among Adolescents

2017 ◽  
Vol 4 (3) ◽  
Author(s):  
Ahmad Rezvan ◽  
H. M. Ramakrishne Gowda ◽  
Lancy D’Souza
Keyword(s):  
Identity Formation ◽  
Parenting Styles ◽  
Collective Identity ◽  
Rural Areas ◽  
Developmental Stages ◽  
Early Stage ◽  
Personality Development ◽  
Late Adolescents ◽  
Authoritarian Parenting ◽  
Significant Difference

Paternal attitudes, beliefs and behaviors that appear as family pattern or parenting styles play a key role in personality development and stabilizing the identity of adolescents. The present study assesses parenting styles and identity formation status of adolescents studying in and around Mysore city. A total of 400 adolescents (200 early and 200 late adolescents) were randomly selected covering Mysore city and nearby rural areas, of which equal number among were male and female adolescents and also equal number of them were from urban and rural areas. They were provided with Parental authority questionnaire (PAQ) developed by Buri (1991) and Aspects of Identity Questionnaire – IV (AIQ – IV) developed by Sampson (1978). PAQ measured perceived parenting styles. The AIQ scale measured personal, Relational Social and Collective areas of identity formation. The collected data were, coded and analyzed using SPSS software. The data was analyzed by Two-way ANOVA to find significant difference if any, in the developmental stages, area of living as well as gender of the participants. Results revealed that, adolescents with authoritarian Parenting styles had higher personal identity formation than adolescents with permissive and authoritarian parenting styles. Developmental stage showed significant influence on all components of identity-Personal, Relational, Social and Collective, where in early stage adolescents had higher identity than adolescents at later stage. In general, this study showed that the developmental stages had considerable effect on the collective identity formation in both early and late adolescents.

scholarly journals Autoradiographic studies of DNA and histone synthesis in successive differentiation stages of pollen grain in Hyacinthus orientalis L.

2014 ◽  
Vol 50 (3) ◽  
pp. 367-380 ◽  
Author(s):  
Elżbieta Bednarska
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
Vegetative Cell ◽  
Developmental Stages ◽  
Generative Cell ◽  
Pollen Grain ◽  
Cell Nuclei ◽  
Hyacinthus Orientalis ◽  
Histone Synthesis ◽  
Generative Cells

DNA and histone synthesis in five consecutive morphological stages of <em>Hyacinthus orientalis</em> L. pollen grain differentiation were studied autoradiographically. DNA synthesis was found to occur in both the generative and the vegetative cell. DNA replication in the generative cell took place when the generative cell was still adhered to the pollen grain wall but already devoid of callose wall. DNA synthesis in the generative cell slightly preceded that in the vegetative cell. Histones were synthesized in phase S of the generative and vegetative cell. In the generative cell histone synthesis also continued at a lower level after completion of DNA replication. In the developmental stages under study the nuclei of the generative cells were decidedly richer in lysine histones than vegetative cell nuclei.

scholarly journals Plant Developmental Stage Drives the Differentiation in Ecological Role of Plant Bacterial and Fungal Microbiomes

2021 ◽  
Author(s):  
Chao Xiong ◽  
Brajesh K. Singh ◽  
Ji-Zheng He ◽  
Yan-Lai Han ◽  
Pei-Pei Li ◽  
...  
Keyword(s):  
Developmental Stage ◽  
Plant Development ◽  
Late Stage ◽  
Developmental Stages ◽  
Early Stage ◽  
Alpha Diversity ◽  
Microbial Interactions ◽  
Disease Suppression ◽  
Fungal Communities ◽  
Ecological Role

Abstract BackgroundPlants live with diverse microbial communities which profoundly affect multiple facets of host performance such as nutrition acquisition, disease suppression and productivity, but if and how host development impacts the assembly, functions and microbial interactions of crop microbiomes are poorly understood. Here we examined both bacterial and fungal communities across soils (rhizosphere and bulk soil), plant epiphytic and endophytic niches (phylloplane, rhizoplane, leaf and root endosphere), and plastic leaf of fake plant (representing environment-originating microbes) at three developmental stages of maize at two contrasting sites, and further explored the potential function of phylloplane microbiomes based on metagenomics.ResultsOur results suggested that plant developmental stage had a much stronger influence on the microbial diversity, composition and interkingdom networks in plant compartment niches than in soils, with the strongest effect in the phylloplane. Air (represented by fake plants) was an important source of phylloplane microbiomes which were co-shaped by both plant development and seasonal environmental factors. Further, we demonstrated that bacterial and fungal communities in plant compartment niches exhibited contrasting response to host developmental stages, with higher alpha diversity and stronger deterministic assembly within bacterial microbiomes at the early stage but a similar pattern within mycobiomes at the late stage. Moreover, we found that bacterial taxa played a more important role in microbial interkingdom network and crop yield prediction at the early stage, while fungal taxa did so at the late stage. Metagenomic analyses further indicated that phylloplane microbiomes possessed higher functional diversity and functional genes involved in nutrient provision and disease resistance at the early stage than the late stage. ConclusionsOur results suggest that host developmental stage profoundly influences plant microbiome assembly and functions, and the bacterial and fungal microbiomes take a differentiated ecological role at different plant development stages. This study provides empirical evidence for host exerting strong effect on plant microbiomes by deterministic selection to meet the physiological requirement of plant developmental stages. These findings have implications for the development of future tools to manipulate microbiome for sustainable increase in primary productivity.

Anatomy, ultrastructure, and functional morphology of the metathoracic tracheal defensive glands of the grasshopper Romalea guttata

1991 ◽  
Vol 69 (8) ◽  
pp. 2100-2108 ◽  
Author(s):  
Douglas W. Whitman ◽  
Johan P. J. Billen ◽  
David Alsop ◽  
Murray S. Blum
Keyword(s):  
Secretory Cell ◽  
Tactile Stimulation ◽  
Defensive Secretion ◽  
Smooth Endoplasmic Reticulum ◽  
Duct Cell ◽  
Secretory Cells ◽  
Glandular Tissue ◽  
Golgi Bodies ◽  
Romalea Guttata ◽  
Defensive Glands

In the lubber grasshopper Romalea guttata, the respiratory system produces, stores, and delivers a phenolic defensive secretion. The exudate is secreted by a glandular epithelium surrounding the metathoracic spiracular tracheal trunks. Embedded in the glandular tissue are multiple secretory units, each comprised of a basal secretory cell and an apical duct cell. Secretory cells have numerous mitochondria, a tubular, smooth endoplasmic reticulum, well-developed Golgi bodies, and a microvillilined vesicle thought to transfer secretion to the intracellular cuticular duct of a duct cell. Ducts empty into the metathoracic tracheal lumina where the exudate is stored behind the closed metathoracic spiracle. Tactile stimulation elicits secretion discharge, which begins when all spiracles except the metathoracic pair are closed and the abdomen is compressed. Increased hemostatic and pneumatic pressures drive air and secretion out of the spiracle with an audible hiss. Both metathoracic spiracles discharge simultaneously. The secretion erupts first as a dispersant spray, then as an adherent froth, and finally assumes the form of a slowly evaporating repellent droplet. Discharge force and number vary with eliciting stimuli, volume of stored secretion, and age, disturbance state, and temperature of the insect. Molting grasshoppers are unable to discharge because the stored exudate is lost with the shed cuticle. The advantages and limitations of a tracheal defensive system are discussed.

The distribution of E-cadherin during Xenopus laevis development

Development ◽  
1991 ◽  
Vol 111 (1) ◽  
pp. 159-169 ◽  
Author(s):  
G. Levi ◽  
B. Gumbiner ◽  
J.P. Thiery
Keyword(s):  
Xenopus Laevis ◽  
Developmental Stages ◽  
Early Embryo ◽  
The Body ◽  
Gut Epithelium ◽  
A Cell ◽  
Well Differentiated ◽  
Sensory Layer ◽  
Endodermal Cells ◽  
E Cadherin

A vast amount of experimental evidence suggests that cell surface molecules involved in cell-to-cell and/or cell-to-substrate interactions participate in the control of basic events in morphogenesis. E-cadherin is a cell adhesion molecule directly implicated in the control of Ca2(+)-dependent interactions between epithelial cells. We report here the patterns of expression of E-cadherin in developmental stages of Xenopus laevis ranging from early embryo to adult using immunofluorescence microscopy. Although its distribution shares some similarities with those of L-CAM in the chicken and E-cadherin/Uvomorulin in the mouse, the distribution of E-cadherin in Xenopus presents several peculiar and unique features. In early stages of Xenopus development, E-cadherin is not expressed. The molecule is first detectable in the ectoderm of late gastrulas (stage 13-13.5 NF). At this time both the external and the sensory layer of the nonneural ectoderm accumulate high levels of E-cadherin while the ectoderm overlying the neural plate and regions of the involuting marginal zone (IMZ) not yet internalized by the movements of gastrulation are E-cadherin-negative. Unlike most other species, endodermal cells express no or very low levels of E-cadherin up to stage 20 NF. Endodermal cells become strongly E-cadherin-positive only when a well-differentiated epithelium forms in the gut. No mesodermal structures are stained during early development. In the placodes, in contrast to other species, E-cadherin disappears very rapidly after placode thickening. During further embryonic development E-cadherin is present in the skin, the gut epithelium, the pancreas, many monostratified epithelia and most glands. Hepatocytes are stained weakly while most other tissues, including the pronephros, are negative. In the mesonephros, the Wolffian duct and some tubules are positive. During metamorphosis a profound restructuring of the body plan takes place under the control of thyroid hormones, which involves the degeneration and subsequent regeneration of several tissues such as the skin and the gut. All newly formed epithelia express high levels of E-cadherin. Surprisingly, degenerating epithelia of both skin and intestine maintain high levels of the protein even after starting to become disorganized and to degenerate. In the adult, staining is strong in the skin, the glands, the lungs, the gut epithelium and the pancreas, weak in the liver and absent from most other tissues. Our results show that the expression of E-cadherin in Xenopus is strongly correlated with the appearance of differentiated epithelia.

Cell proliferation in the developing wing-bud of normal and talpid3 mutant chick embryos

Development ◽  
1975 ◽  
Vol 34 (3) ◽  
pp. 589-607
Author(s):  
D. A. Ede ◽  
O. P. Flint ◽  
P. Teague
Keyword(s):  
Cell Cycle ◽  
Early Stage ◽  
Mitotic Rate ◽  
Mitotic Division ◽  
Chick Embryos ◽  
Division Rate ◽  
Cell Cycle Time ◽  
Continuous Sampling ◽  
Wing Bud ◽  
Marked Drop

Previous measurements on mitotic division rate or cell cycle time have been made on samples from a few discrete limb regions or by continuous sampling, but only down a unidimensional limb axis, disregarding morphological discontinuities such as the presence or absence of cartilage. This study presents a new analysis on normal and talpid3 mutant chick embryos, measuring mitotic rate and also cell density through the central proximo-distal axis and at the limb periphery, taking into account the development of cartilage regions. Differentiation of cartilage is correlated with a marked drop in mitotic rate, accounting for a proximo-distal gradient of mitosis in central counts which was not observed at the limb periphery. Talpid3 limbs at an early stage show a central mitotic gradient, but the reverse of that observed in normal limbs.

The Spermatozoon of Actinia Equina L. Var. Mesembryanthemum

1980 ◽  
Vol 60 (1) ◽  
pp. 193-204 ◽  
Author(s):  
A. U. Larkman ◽  
M. A. Carter
Keyword(s):  
Fine Structure ◽  
Sexual Reproduction ◽  
Recent Work ◽  
Developmental Stages ◽  
Early Stage ◽  
Genetic Material ◽  
Sea Anemones ◽  
Free Living ◽  
Pass Through ◽  
Parent Female

Actinia equina var. mesembryanthemum, the beadlet anemone (Stephenson, 1935), is a very common and widely distributed littoral anthozoan, whose sexual reproduction shows several interesting characteristics. Adult sea anemones of both sexes brood planulae and more advanced developmental stages within the gastrovascular cavity, although earlier embryonic stages are rarely found brooded in this way. Chia & Rostron (1970) suggest that embryos are expelled from the parent female anemone at an early stage and pass through a free-living phase before re-entering anemones of either sex for brooding. However, recent work (Cain, 1974) suggests that juvenile anemones are genetically related to the adult anemones in which they are brooded, and also the distribution of genetic material during sexual reproduction appears to be abnormal (Carter & Thorp, 1979). In an attempt to achieve a better understanding of the unusual sexual reproduction of this species, an ultrastructural investigation of gametogenesis was undertaken. This paper describes the fine structure of the spermatozoon within the testis.

scholarly journals Temporospatial Flavonoids Metabolism Variation in Ginkgo biloba Leaves

2020 ◽  
Vol 11 ◽  
Author(s):  
Ying Guo ◽  
Tongli Wang ◽  
Fang-Fang Fu ◽  
Yousry A. El-Kassaby ◽  
Guibin Wang
Keyword(s):  
Ginkgo Biloba ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Early Stage ◽  
Sunshine Duration ◽  
Flavonoid Biosynthesis ◽  
Flavonoid Glycosides ◽  
Biosynthesis Pathway ◽  
Flavonoids Biosynthesis ◽  
Flavonoid Biosynthesis Pathway

Ginkgo (Ginkgo biloba L.) is a high-value medicinal tree species characterized by its flavonoids beneficial effects that are abundant in leaves. We performed a temporospatial comprehensive transcriptome and metabolome dynamics analyses of clonally propagated Ginkgo plants at four developmental stages (time: May to August) across three different environments (space) to unravel leaves flavonoids biosynthesis variation. Principal component analysis revealed clear gene expression separation across samples from different environments and leaf-developmental stages. We found that flavonoid-related metabolism was more active in the early stage of leaf development, and the content of total flavonoid glycosides and the expression of some genes in flavonoid biosynthesis pathway peaked in May. We also constructed a co-expression regulation network and identified eight GbMYBs and combining with other TF genes (3 GbERFs, 1 GbbHLH, and 1 GbTrihelix) positively regulated the expression of multiple structural genes in the flavonoid biosynthesis pathway. We found that part of these GbTFs (Gb_11316, Gb_32143, and Gb_00128) expressions was negatively correlated with mean minimum temperature and mean relative humidity, while positively correlated with sunshine duration. This study increased our understanding of the molecular mechanisms of flavonoids biosynthesis in Ginkgo leaves and provided insight into the proper production and management of Ginkgo commercial plantations.

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