Poly(ADP-Ribose)Polymerase Activity Controls Plant Growth by Promoting Leaf Cell Number

Moss-bags were applied to study the effect of contamination in three standing water bodies in Bulgaria (Kardzhali, Studen Kladenets and Zhrebchevo Reservoirs), the first two with old industrial contamination and the last polluted with short-chain chlorinated paraffins (SCCPs). Fontinalis antipyretica Hedw. collected from background (unpolluted) site was placed in cages for a period of 30 days. The present study examined whether inorganic and organic pollution detected with moss-bags resulted in corresponding differences in molecular, chemical and micromorphological markers. Suppressed large subunit of ribulose-1,5-bisphosphate carboxylase (rbcL) expression was assessed in moss-bags from two of the reservoirs, contaminated with heavy metals. There was a decrease of the total phenolic content (TPC) in the moss-bags, which provides a basis for further studies of the chemical content of aquatic mosses. Fontinalis antipyretica also showed a response through leaf micromorphological characteristics. In the all three reservoirs, an increase of the twig leaf cell number was recorded (p ≤ 0.01 for Kardzhali and p ≤ 0.001 for Studen Kladenets and Zhrebchevo reservoirs), as well as of the stem leaf cell number in Zhrebchevo Reservoir (p ≤ 0.001). On the contrary, the width of the cells decreased in the studied anthropogenically impacted reservoirs. All three studied groups of biomarkers (molecular, chemical and micromorphological) appeared to be sensitive to freshwater pollution. The results achieved indicated that rbcL gene expression, TPC, cell number and size are promising biomonitoring tools.

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Effects of Constant and Variable Nitrogen Supply on Sunflower (Helianthus annuus L.) Leaf Cell Number and Size

Annals of Botany ◽

10.1006/anbo.1999.0954 ◽

1999 ◽

Vol 84 (5) ◽

pp. 599-606 ◽

Cited By ~ 22

Author(s):

N TRÁPANI

Keyword(s):

Helianthus Annuus ◽

Cell Number ◽

Nitrogen Supply ◽

Leaf Cell ◽

Helianthus Annuus L

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The ultrastructure of acinar cells in the external orbital gland of young and old male rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082248 ◽

1978 ◽

Vol 36 (2) ◽

pp. 276-277

Author(s):

R. Carriere

Keyword(s):

Young Adulthood ◽

Acinar Cells ◽

Cell Number ◽

Male Rats ◽

Polyploid Cell ◽

Secretory Cells ◽

Age Changes ◽

Albino Rat ◽

Golgi Membranes ◽

Diploid Cells

The external orbital gland of the albino rat exhibits both sexual dimorphism and histological age changes. In males, many cells attain a remarkable degree of polyploidy and an increase of polyploid cell number constitutes the major age change until young adulthood. The acini of young adults have a small lumen and are composed of tall serous cells. Subsequently, many acini acquire a larger lumen with an irregular outline while numerous vacuoles accumulate throughout the secretory cells. At the same time, vesicular acini with a large lumen surrounded by pale-staining low cuboidal diploid cells begin to appear and their number increases throughout old age. The fine structure of external orbital glands from both sexes has been explored and in considering acinar cells from males, emphasis was given to the form of the Golgi membranes and to nuclear infoldings of cytoplasmic constituents.

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Effects of the pseudomonad phytotoxin coronatine on tomato leaf structure and ultrastructure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140683 ◽

1995 ◽

Vol 53 ◽

pp. 862-863

Author(s):

D.A. Palmer ◽

C.L. Bender

Keyword(s):

Pseudomonas Syringae ◽

Membrane Integrity ◽

Leaf Tissue ◽

Cell Number ◽

Cell Ultrastructure ◽

Response To Treatment ◽

Prominent Symptom ◽

Chlorophylls A And B ◽

Cell Dimensions ◽

Structure And Ultrastructure

Coronatine is a non-host-specific phytotoxin produced by several members of the Pseudomonas syringae group of pathovars. The toxin acts as a virulence factor in P. syringae pv. tomato, allowing the organism to multiply to a higher population density and develop larger lesions than mutant strains unable to produce the toxin. The most prominent symptom observed in leaf tissue treated with coronatine is an intense spreading chlorosis; this has been attributed to a loss of chlorophylls a and b in tobacco. Coronatine's effects on membrane integrity and cell ultrastructure have not been previously investigated. The present study describes changes in tomato leaves in response to treatment with purified coronatine, infection by a coronatine-producing strain of P. syringae pv. tomato, and infection by a cor" mutant.In contrast to H2O-treated tissue, coronatine-treated tissue showed a diffuse chlorosis extending approximately 5 mm from the inoculation site. Leaf thickness, cell number, and cell dimensions were similar for both healthy and coronatine-treated, chlorotic tissue; however, the epidermal cell walls were consistently thicker in coronatine-treated leaves (Figs, la and lb).

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Apoptosis and development

Essays in Biochemistry ◽

10.1042/bse0390011 ◽

2003 ◽

Vol 39 ◽

pp. 11-24 ◽

Cited By ~ 6

Author(s):

Justin V McCarthy

Keyword(s):

Drosophila Melanogaster ◽

Mammalian Cells ◽

Cell Number ◽

Model Organisms ◽

Biological Processes ◽

Nematode Caenorhabditis Elegans ◽

Apoptotic Pathway ◽

Genetic Pathways ◽

Evolutionarily Conserved ◽

Multicellular Organisms

Apoptosis is an evolutionarily conserved process used by multicellular organisms to developmentally regulate cell number or to eliminate cells that are potentially detrimental to the organism. The large diversity of regulators of apoptosis in mammalian cells and their numerous interactions complicate the analysis of their individual functions, particularly in development. The remarkable conservation of apoptotic mechanisms across species has allowed the genetic pathways of apoptosis determined in lower species, such as the nematode Caenorhabditis elegans and the fruitfly Drosophila melanogaster, to act as models for understanding the biology of apoptosis in mammalian cells. Though many components of the apoptotic pathway are conserved between species, the use of additional model organisms has revealed several important differences and supports the use of model organisms in deciphering complex biological processes such as apoptosis.

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Mechanisms of ethylene biosynthesis and response in plants

Essays in Biochemistry ◽

10.1042/bse0580061 ◽

2015 ◽

Vol 58 ◽

pp. 61-70 ◽

Cited By ~ 11

Author(s):

Paul B. Larsen

Keyword(s):

Plant Growth ◽

Growth And Development ◽

Ethylene Biosynthesis ◽

Unsaturated Hydrocarbon ◽

Flower Senescence ◽

Detailed Knowledge ◽

Plant Growth And Development ◽

Step Process ◽

Ethylene Response ◽

Ethylene Signalling

Ethylene is the simplest unsaturated hydrocarbon, yet it has profound effects on plant growth and development, including many agriculturally important phenomena. Analysis of the mechanisms underlying ethylene biosynthesis and signalling have resulted in the elucidation of multistep mechanisms which at first glance appear simple, but in fact represent several levels of control to tightly regulate the level of production and response. Ethylene biosynthesis represents a two-step process that is regulated at both the transcriptional and post-translational levels, thus enabling plants to control the amount of ethylene produced with regard to promotion of responses such as climacteric flower senescence and fruit ripening. Ethylene production subsequently results in activation of the ethylene response, as ethylene accumulation will trigger the ethylene signalling pathway to activate ethylene-dependent transcription for promotion of the response and for resetting the pathway. A more detailed knowledge of the mechanisms underlying biosynthesis and the ethylene response will ultimately enable new approaches to be developed for control of the initiation and progression of ethylene-dependent developmental processes, many of which are of horticultural significance.

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