scholarly journals Arabidopsis glucosinolate storage cells transform into phloem fibres at late stages of development

2019 ◽  
Vol 70 (16) ◽  
pp. 4305-4317 ◽  
Author(s):  
Pascal Hunziker ◽  
Barbara Ann Halkier ◽  
Alexander Schulz
Keyword(s):  
Morphological Changes ◽  
Smooth Endoplasmic Reticulum ◽  
Chemical Defence ◽  
Herbaceous Plant ◽  
Stages Of Development ◽  
Golgi Bodies ◽  
Early Stages ◽  
High Concentrations ◽  
Storage Cells ◽  
Late Stages

Abstract The phloem cap of Arabidopsis thaliana accumulates glucosinolates that yield toxic catabolites upon damage-induced hydrolysis. These defence compounds are stored in high concentrations in millimetre long S-cells. At early stages of development, S-cells initiate a process indicative of programmed cell death. How these cells are maintained in a highly turgescent state following this process is currently unknown. Here, we show that S-cells undergo substantial morphological changes during early differentiation. Vacuolar collapse and rapid clearance of the cytoplasm did not occur until senescence. Instead, smooth endoplasmic reticulum, Golgi bodies, vacuoles, and undifferentiated plastids were observed. Lack of chloroplasts indicates that S-cells depend on metabolite supply from neighbouring cells. Interestingly, TEM revealed numerous plasmodesmata between S-cells and neighbouring cells. Photoactivation of a symplasmic tracer showed coupling with neighbouring cells that are involved in glucosinolate synthesis. Hence, symplasmic transport might contribute to glucosinolate storage in S-cells. To investigate the fate of S-cells, we traced them in flower stalks from the earliest detectable stages to senescence. At late stages, S-cells were shown to deposit thick secondary cell walls and transform into phloem fibres. Thus, phloem fibres in the herbaceous plant Arabidopsis pass a pronounced phase of chemical defence during early stages of development.

Larval morphology of Dart-Poison Frogs (Anura: Dendrobatoidea: Aromobatidae and Dendrobatidae)

Zootaxa ◽  
2013 ◽  
Vol 3637 (5) ◽  
pp. 569 ◽  
Author(s):  
DAVID A. SÁNCHEZ
Keyword(s):  
Digestive System ◽  
Larval Morphology ◽  
Stages Of Development ◽  
Taxonomic Assignment ◽  
Digestive Tube ◽  
Early Stages ◽  
Constant Diameter ◽  
The Family ◽  
Upper Jaw ◽  
Late Stages

Tadpoles in the superfamily Dendrobatoidea (families Aromobatidae and Dendrobatidae), housed in zoological collections or illustrated in publications, were studied. For the most part, tadpoles of species within the family Aromobatidae, the subfamilies Colostethinae and Hyloxalinae (of the family Dendrobatidae), and those of the genus Phyllobates, Dendrobatinae (Dendrobatidae) have slender anterior jaw sheaths with a medial notch and slender lateral processes, triangular fleshy projections on the inner margin of the nostrils and digestive tube with constant diameter and color and its axis sinistrally directed, concealing the liver and other organs. These morphologies are different from the ones observed in tadpoles of species included in the Dendrobatinae (minus Phyllobates). Exceptions to these morphological arrangements are noted, being the digestive system arrangement and the nostril ornamentation more plastic than the shape of the upper jaw sheath. Tadpoles of all species of the Dendrobatoidea have similar disposition of digestive organs in early stages, but differentiate in late stages of development. Classifying the upper jaw sheath into the two recognized states is possible from very early stages of development, but gut disposition and nostril ornamentation cannot be determined until late in development, making classification and taxonomic assignment of tadpoles based on these morphological features challenging.

scholarly journals STUDIES ON SEEDS

1971 ◽  
Vol 48 (2) ◽  
pp. 387-394 ◽  
Author(s):  
Hilton H. Mollenhauer ◽  
Clara Totten
Keyword(s):  
Electron Microscopy ◽  
Cell Shape ◽  
Stages Of Development ◽  
Early Stages ◽  
Late Stages

Several fixation procedures were studied to determine those most suitable for preservation of seeds during late stages of development and early stages of germination. These are the periods when the tissues are partially dehydrated and are most difficult to fix for electron microscopy. It was found that a prefixation with a mixture of glutaraldehyde, reconstituted formaldehyde (i.e. paraformaldehyde), and acrolein, followed by a postfixation in OsO4 or KMnO4, gives very acceptable images. The results also indicate that glutaraldehyde is necessary for preservation of cell shape, paraformaldehyde for stabilization of reserve proteins, and acrolein for rapid penetration of tissues. Phosphate, cacodylate, and collidine are all acceptable buffers, although collidine gives the most consistent results.

scholarly journals COMPARATIVE CHARACTERISTICS OF THE MORPHOLOGICAL CHANGES OF NEPHRON TUBULES AT THE EARLY AND LATE STAGES OF THE CHRONIC OPIOID EFFECT

2019 ◽  
pp. 19-22
Author(s):  
Lesya Mateshuk-Vatseba ◽  
Iryna Vilkhova ◽  
Anna Bekesevych ◽  
Yeugen Paltov ◽  
Elena Kantser
Keyword(s):  
Morphological Changes ◽  
Mature Male ◽  
Male Rats ◽  
Histological Investigation ◽  
Early Stages ◽  
Hematoxylin And Eosin ◽  
Convoluted Tubules ◽  
Late Stages ◽  
Sexually Mature ◽  
Proximal Convoluted Tubules

The aim of the study is the examination of the nephron tubules morphological changes at the early and late stages of the experimental chronic opioid effect. Varying degrees of the morphological changes of proximal convoluted tubules, loops of Henle and distal convoluted tubules under chronic nalbuphine effect in the dynamics have been detected. The materials of the study – kidneys of 56 sexually mature male-rats. The experimental animals received daily intramuscular nalbuphine injections for 98 days. From the first to the fourteenth day of the experiment the dose of nalbuphine was 0,212 mg/kg. Every next two weeks nalbuphine injections were done in increasing doses. For histological investigation was used commonly agreed method. The colouring was performed using hematoxylin and eosin as well as azan by Heidenhain's method. Varying degrees of morphological changes of proximal convoluted tubules, loops of Henle and distal convoluted tubules under continuous nalbuphine injection in the dynamics have been detected. The most vivid alterative changes can be observed in proximal convoluted tubules both: at the early and late stages of the experiment. At the early stages as of the 14th day of the experiment signs of granular dystrophy appear, as of the 28th day – necrotic changes, progressing further at the late stages of the experiment. The loops of Henle undergo sporadic destructive changes at the early stages and at the beginning of the late stage of the experiment. Distal convoluted tubules have been necrotic altered only at the late stages of the experiment.

Effect of verapamil on cytoplasmic distribution of granules and microfilaments in amphibian urinary bladder

1988 ◽  
Vol 46 ◽  
pp. 324-325
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Morphological Changes ◽  
Granular Cell ◽  
Cytosolic Calcium ◽  
Calcium Storage ◽  
Amphibian Urinary Bladder ◽  
Vesicular Membrane ◽  
High Concentrations ◽  
Cytoskeletal System

The amphibian urinary bladder has been used as a ‘model’ system for studies of the mechanism of action of antidiuretic hormone (ADH) in stimulating transepithelial water flow. The increase in water permeability is accompanied by morphological changes that include the stimulation of apical microvilli, mobilization of microtubules and microfilaments and vesicular membrane fusion events . It has been shown that alterations in the cytosolic calcium concentrations can inhibit ADH transmembrane water flow and induce alterations in the epithelial cell cytomorphology, including the cytoskeletal system . Recently, the subapical granules of the granular cell in the amphibian urinary bladder have been shown to contain high concentrations of calcium, and it was suggested that these cytoplasmic constituents may act as calcium storage sites for intracellular calcium homeostasis. The present study utilizes the calcium antagonist, verapamil, to examine the effect of calcium deprivation on the cytomorphological features of epithelial cells from amphibian urinary bladder, with particular emphasis on subapical granule and microfilament distribution.

scholarly journals Association of beta-cytoplasmic actin with high concentrations of acetylcholine receptor (AChR) in normal and anti-AChR-treated primary rat muscle cultures.

1984 ◽  
Vol 32 (9) ◽  
pp. 973-981 ◽  
Author(s):  
B W Lubit
Keyword(s):  
Acetylcholine Receptor ◽  
Acetylcholine Receptors ◽  
Neuromuscular Junctions ◽  
Morphological Changes ◽  
Muscle Cells ◽  
High Concentration ◽  
Rat Muscle ◽  
Cytoplasmic Actin ◽  
High Concentrations

Previous immunocytochemical studies in which an antibody specific for mammalian cytoplasmic actin was used showed that a high concentration of cytoplasmic actin exists at neuromuscular junctions of rat muscle fibers such that the distribution of actin corresponded exactly to that of the acetylcholine receptors. Although clusters of acetylcholine receptors also are present in noninnervated rat and chick muscle cells grown in vitro, neither the mechanism for the formation and maintenance of these clusters nor the relationship of these clusters to the high density of acetylcholine receptors at the neuromuscular junction in vivo are known. In the present study, a relationship between beta-cytoplasmic actin and acetylcholine receptors in vitro has been demonstrated immunocytochemically using an antibody specific for the beta-form of cytoplasmic actin. Networks of cytoplasmic actin-containing filaments were found in discrete regions of the myotube membrane that also contained high concentrations of acetylcholine receptors; such high concentrations of acetylcholine receptors have been described in regions of membrane-substrate contact. Moreover, when primary rat myotubes were exposed to human myasthenic serum, gross morphological changes, accompanied by an apparent rearrangement of the cytoplasmic actin-containing cytoskeleton, were produced. Although whether the distribution of cytoplasmic actin-containing structures was influenced by the organization of acetylcholine receptor or vice versa cannot be determined from these studies, these findings suggest that in primary rat muscle cells grown in vitro, acetylcholine receptors and beta-cytoplasmic actin-containing structures may be somehow connected.

Comparative leaf development of aerial and aquatic growth forms of Myriophyllum aquaticum

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 421-430 ◽  
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Epidermal Cells ◽  
The Other ◽  
Developmental Study ◽  
Growth Forms ◽  
Myriophyllum Aquaticum ◽  
Stages Of Development ◽  
Qualitative And Quantitative ◽  
Early Stages ◽  
Other Hand

Myriophyllum aquaticum (Vell.) Verdc. produces two morphologically different forms of leaves based on whether they are aerial or aquatic. The objective of this study was to determine whether there are any similarities or differences between these two growth forms during their early stages of development. A comparative developmental study of aerial and aquatic growth forms of M. aquaticum was conducted from a qualitative and quantitative perspective using a scanning electron microscope. The pattern of leaf and lobe initiation such as their origin and shape were similar in both growth forms until the fourth plastochron (stage P4). Differences between the two growth forms became evident from stage P5 onward, where a larger shoot apical meristem (SAM), elongated epidermal cells, shorter and slightly more numerous lobes, as well as the presence of appendage-like structures characterized aquatic growth forms. On the other hand, aerial growth forms had smaller SAM, bulb-like epidermal cells, and longer and slightly less numerous leaf lobes. Significant differences between growth forms were noted for parameters such as volume of SAM, length of terminal, first, and middle lobes, as well as the length from first to last lobes. The volume of the SAM of aquatic shoot tips was always greater than aerial forms. On the other hand, lobes of aerial forms were always longer than the aquatic counterpart during early stages of development. This study on the development of M. aquaticum shows that the aerial and aquatic growth forms diverge from their early stages of development.

XV. On the development of the parasitic isopoda

1878 ◽  
Vol 169 ◽  
pp. 505-521 ◽  
Keyword(s):  
The Body ◽  
The Other ◽  
Stages Of Development ◽  
Early Stages ◽  
Abdominal Appendages ◽  
Pair Of Antennae

The following paper contains an account of observations on the development of the species Cymothoa œstroides and C . parallela of Milne Edwards; but the forms of the young seem to show that several species are really included under these two names. In the early stages of development the only observable difference that exists between the embryos is one of size, but in the later stages they differ very markedly from each other in their external characters. From adult individuals answering the description of C . œstroides I have obtained four varieties of embryos: two with long antennae and two with short.* In the two former the first pair of antennae are but slightly longer than the head, while the second pair are longer than the body; the eyes are small. In one of the varieties thus characterised the abdominal appendages are fringed with long hairs (fig. 20), and in the other they are smooth.

Morphological variations of Phrosina semilunata Risso, 1822 juveniles (Crustacea: Amphipoda: Hyperiidea), new evidence from the Gulf of Mexico

Zootaxa ◽  
2021 ◽  
Vol 4995 (3) ◽  
pp. 594-600
Author(s):  
MARCO VIOLANTE-HUERTA ◽  
LAURA SANVICENTE-AÑORVE ◽  
MARGARITA HERMOSO-SALAZAR ◽  
AURORA MARRÓN-BECERRA
Keyword(s):  
Gulf Of Mexico ◽  
Monotypic Genus ◽  
Stages Of Development ◽  
Morphological Variations ◽  
Stages Of Growth ◽  
Early Stages ◽  
Southern Gulf Of Mexico ◽  
New Evidence ◽  
Lack Of Knowledge

Lack of knowledge of morphological variations during growth of amphipod crustaceans can result in misidentification of species. In this study, we advance the knowledge of morphological variations of juveniles of the monotypic genus Phrosina Risso, 1822 collected in the oceanic province of the southern Gulf of Mexico. The juveniles differed from the adults mainly in the morphology of pereopods 3 & 4 in that the carpal process is parallel to the propodus, also the rami of the pleopoda consist of only four segments, uropoda 3 are more lanceolate, and the uropoda bear a large prominent spine terminally. These morphological variations have not been described for the species previously. Therefore, the current observations enrich the description of P. semilunata in the early stages of growth and support the need for further taxonomical studiest that could help identify species at different stages of development.  

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