Cell biology of bordered-pit formation in balsam-fir trees

A mature bordered pit in secondary xylem of Pinaceae comprises a circular border of secondary-wall material that protrudes into the tracheid lumen and is punctuated by a centralized aperture through which sap flows. The overarching border encloses a pit chamber within which is a “membrane”, or diaphragm, consisting of a central torus and margo strands. Bordered-pit pairs are abundantly present in all woods, and their membranes serve as swinging-diaphragm check valves regulating sap flow between adjoining tracheary elements, simultaneously trapping emboli and particulates in water as it moves from roots to leaves. The cell biology of bordered-pit formation in cambial derivatives of Abies balsamea (L.) Mill. was investigated by light and scanning electron microscopy during early stages of cellular differentiation of cambial derivatives into secondary xylem tracheids. A bordered-pit template (BPT), a bordered-pit organelle (BPO), a bordered-pit basal disk, and additional novel structures were found to be associated with bordered-pit formation. Evidence was found that the membrane does not comprise residual compound middle lamella; rather, the membrane forms de novo as BPO remnants. A cell-biology model and new terminology are introduced to explain how BPTs, BPOs, and basal disks contribute to successive stages in formation of bordered-pit pairs.

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Ovarian Cancer Dissemination—A Cell Biologist’s Perspective

Cancers ◽

10.3390/cancers11121957 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1957 ◽

Cited By ~ 2

Author(s):

Sadaf Farsinejad ◽

Thomas Cattabiani ◽

Taru Muranen ◽

Marcin Iwanicki

Keyword(s):

Ovarian Cancer ◽

Cell Biology ◽

De Novo ◽

Peritoneal Dissemination ◽

Cellular Processes ◽

Disease States ◽

A Cell ◽

Cancer Dissemination ◽

Current Stage

Epithelial ovarian cancer (EOC) comprises multiple disease states representing a variety of distinct tumors that, irrespective of tissue of origin, genetic aberrations and pathological features, share common patterns of dissemination to the peritoneal cavity. EOC peritoneal dissemination is a stepwise process that includes the formation of malignant outgrowths that detach and establish widespread peritoneal metastases through adhesion to serosal membranes. The cell biology associated with outgrowth formation, detachment, and de novo adhesion is at the nexus of diverse genetic backgrounds that characterize the disease. Development of treatment for metastatic disease will require detailed characterization of cellular processes involved in each step of EOC peritoneal dissemination. This article offers a review of the literature that relates to the current stage of knowledge about distinct steps of EOC peritoneal dissemination, with emphasis on the cell biology aspects of the process.

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Pit Pairs With Tori in the Wood of Osmanthus Americanus (Oleaceae)

IAWA Journal ◽

10.1163/22941932-90001052 ◽

1987 ◽

Vol 8 (3) ◽

pp. 237-244 ◽

Cited By ~ 3

Author(s):

Roland R. Dute ◽

Ann E. Rushing

Keyword(s):

Middle Lamella ◽

Radial Component ◽

Wall Material ◽

Sodium Chlorite ◽

Variable Amount ◽

Tracheary Elements ◽

Bordered Pit ◽

Compound Middle Lamella ◽

Pit Membrane

Bordered pit pairs connecting tracheary elements in the wood of Osmanthus americanus (L.) Benth. ' Hook. ex Gray contained a torus in the pit membrane. This structure is approximately 2.5 μm in diameter, and is located at or near the centre of the pit membrane. The encrusting material of the torus could be removed by treatment with sodium chlorite. Thin seetions through theJorus showed it to consist of a pad of wall material appressed to either side of the compound middle lamella. The membrane surrounding the torus (the margo) consisted of fibrils and a variable amount of enc10sing matrix. The fibrils were generally c1oseIy packed and randomly oriented, although occasionally a radial component was also present. Aspiration of the pit membrane in air-dried material caused the torus to seal off one of the pit apertures. During this process the torus probably prevented rupture of the pit membrane at that site.

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The terminal heme synthetic enzyme, Coproheme Decarboxylase, coordinates heme synthesis and uptake in response to iron in Mycobacteria

10.1101/2021.05.10.443464 ◽

2021 ◽

Author(s):

Rebecca K. Donegan ◽

Jacqueline Copeland ◽

Stanzin Edgha ◽

Gabriel Brown ◽

Owen F. Hale ◽

...

Keyword(s):

Cell Biology ◽

De Novo ◽

Reductase Activity ◽

Human Pathogen ◽

Biosynthetic Enzyme ◽

De Novo Synthesis ◽

Heme Uptake ◽

Heme Synthesis ◽

A Cell ◽

Ferrous Heme

Heme is both an essential cofactor and an abundant source of nutritional iron for the human pathogen Mycobacterium tuberculosis (Mtb). While heme is required for Mtb survival and virulence, it is also potentially cytotoxic. Since Mtb has the ability to both make and uptake heme, the de novo synthesis of heme and its acquisition from the host must be balanced in order to mitigate heme toxicity. However, the mechanisms employed by Mtb to regulate heme uptake, synthesis, and bioavailability are poorly understood. By integrating ratiometric heme sensors with mycobacterial genetics, cell biology, and biochemistry, we determined that the terminal heme biosynthetic enzyme, coproheme decarboxylase (ChdC), plays a role in regulating both heme bioavailability and uptake in Mtb. Moreover, we found that Mtb has a preference for scavenging reduced ferrous heme and exhibits a cell surface heme reductase activity that is regulated by ChdC. In Mtb, ChdC expression is down-regulated when iron is limiting, which in-turn increases both heme import and bioavailability. Such a mechanism may serve to protect cells from heme toxicity while trying to meet the nutritional demand for iron. Our results demonstrate that heme synthesis and uptake are tightly integrated in mycobacteria and represent the first example of a heme synthetic enzyme playing a role in controlling heme uptake.

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CALINCA—A Novel Pipeline for the Identification of lncRNAs in Podocyte Disease

Cells ◽

10.3390/cells10030692 ◽

2021 ◽

Vol 10 (3) ◽

pp. 692

Author(s):

Sweta Talyan ◽

Samantha Filipów ◽

Michael Ignarski ◽

Magdalena Smieszek ◽

He Chen ◽

...

Keyword(s):

Cell Biology ◽

Mammalian Cells ◽

De Novo ◽

Depth Information ◽

Gene Products ◽

Classical Analysis ◽

Protein Coding ◽

Bioinformatic Pipeline ◽

Non Coding Rnas ◽

Filtration Unit

Diseases of the renal filtration unit—the glomerulus—are the most common cause of chronic kidney disease. Podocytes are the pivotal cell type for the function of this filter and focal-segmental glomerulosclerosis (FSGS) is a classic example of a podocytopathy leading to proteinuria and glomerular scarring. Currently, no targeted treatment of FSGS is available. This lack of therapeutic strategies is explained by a limited understanding of the defects in podocyte cell biology leading to FSGS. To date, most studies in the field have focused on protein-coding genes and their gene products. However, more than 80% of all transcripts produced by mammalian cells are actually non-coding. Here, long non-coding RNAs (lncRNAs) are a relatively novel class of transcripts and have not been systematically studied in FSGS to date. The appropriate tools to facilitate lncRNA research for the renal scientific community are urgently required due to a row of challenges compared to classical analysis pipelines optimized for coding RNA expression analysis. Here, we present the bioinformatic pipeline CALINCA as a solution for this problem. CALINCA automatically analyzes datasets from murine FSGS models and quantifies both annotated and de novo assembled lncRNAs. In addition, the tool provides in-depth information on podocyte specificity of these lncRNAs, as well as evolutionary conservation and expression in human datasets making this pipeline a crucial basis to lncRNA studies in FSGS.

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Reconstruction ofmreBExpression in Staphylococcus aureus via a Collection of New Integrative Plasmids

Applied and Environmental Microbiology ◽

10.1128/aem.00759-14 ◽

2014 ◽

Vol 80 (13) ◽

pp. 3868-3878 ◽

Cited By ~ 11

Author(s):

Ana Yepes ◽

Gudrun Koch ◽

Andrea Waldvogel ◽

Juan-Carlos Garcia-Betancur ◽

Daniel Lopez

Keyword(s):

Staphylococcus Aureus ◽

Cell Wall ◽

Cell Biology ◽

Genetic Manipulation ◽

Protein Localization ◽

Antibiotic Resistance Genes ◽

Wall Material ◽

Content Type ◽

Genetic Manipulations ◽

Discrete Structures

ABSTRACTProtein localization has been traditionally explored in unicellular organisms, whose ease of genetic manipulation facilitates molecular characterization. The two rod-shaped bacterial modelsEscherichia coliandBacillus subtilishave been prominently used for this purpose and have displaced other bacteria whose challenges for genetic manipulation have complicated any study of cell biology. Among these bacteria is the spherical pathogenic bacteriumStaphylococcus aureus. In this report, we present a new molecular toolbox that facilitates gene deletion in staphylococci in a 1-step recombination process and additional vectors that facilitate the insertion of diverse reporter fusions into newly identified neutral loci of theS. aureuschromosome. Insertion of the reporters does not add any antibiotic resistance genes to the chromosomes of the resultant strains, thereby making them amenable for further genetic manipulations. We used this toolbox to reconstitute the expression ofmreBinS. aureus, a gene that encodes an actin-like cytoskeletal protein which is absent in coccal cells and is presumably lost during the course of speciation. We observed that inS. aureus, MreB is organized in discrete structures in association with the membrane, leading to an unusual redistribution of the cell wall material. The production of MreB also caused cell enlargement, but it did not revert staphylococcal shape. We present interactions of MreB with key staphylococcal cell wall-related proteins. This work facilitates the useS. aureusas a model system in exploring diverse aspects of cellular microbiology.

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e-Book on plant virus infection—a cell biology perspective

Frontiers in Plant Science ◽

10.3389/fpls.2013.00203 ◽

2013 ◽

Vol 4 ◽

Cited By ~ 2

Author(s):

Jean-François Laliberté ◽

Peter Moffett ◽

Hélène Sanfaçon ◽

Aiming Wang ◽

Richard S. Nelson ◽

...

Keyword(s):

Virus Infection ◽

Cell Biology ◽

Plant Virus ◽

A Cell

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(A) Cell biology of epithelia

Advanced Drug Delivery Reviews ◽

10.1016/0169-409x(91)90012-2 ◽

1991 ◽

Vol 7 (3) ◽

pp. 313-338 ◽

Cited By ~ 16

Author(s):

Martin Mackay ◽

Ian Williamson ◽

John Hastewell

Keyword(s):

Cell Biology ◽

A Cell

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DNA methylation in 5-aza-2'-deoxycytidine-resistant variants of C3H 10T1/2 C18 cells

Molecular and Cellular Biology ◽

10.1128/mcb.4.10.2098-2102.1984 ◽

1984 ◽

Vol 4 (10) ◽

pp. 2098-2102

Author(s):

E Flatau ◽

F A Gonzales ◽

L A Michalowsky ◽

P A Jones

Keyword(s):

Cell Line ◽

Cytosine Methylation ◽

De Novo ◽

Lethal Dose ◽

Cytotoxic Effects ◽

Drug Treatments ◽

A Cell ◽

Mouse Cells ◽

Low Levels ◽

Dna Cytosine Methylation

A cell line (T17) was derived from C3H 10T1/2 C18 cells after 17 treatments with increasing concentrations of 5-aza-2'-deoxycytidine. The T17 cell line was very resistant to the cytotoxic effects of 5-aza-2'-deoxycytidine, and the 50% lethal dose for 5-aza-2'-deoxycytidine was ca. 3 microM, which was 30-fold greater than that of the parental C3H 10T1/2 C18 cells. Increased drug resistance was not due to a failure of the T17 cell line to incorporate 5-aza-2'-deoxycytidine into DNA. The cells were also slightly cross-resistant to 5-azacytidine. The percentage of cytosines modified to 5-methylcytosine in T17 cells was 0.7%, a 78% decrease from the level of 3.22% in C3H 10T1/2 C18 cells. The DNA cytosine methylation levels in several clones isolated from the treated lines were on the order of 0.7%, and clones with methylation levels lower than 0.45% were not obtained even after further drug treatments. These highly decreased methylation levels appeared to be unstable, and DNA modification increased as the cells divided in the absence of further drug treatment. The results suggest that it may not be possible to derive mouse cells with vanishingly low levels of 5-methylcytosine and that considerable de novo methylation can occur in cultured lines.

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