scholarly journals Infection of Barley by Brome Mosaic Virus Is Restricted Predominantly to Cells in and Associated with Veins through a Temperature-Dependent Mechanism

1999 ◽  
Vol 12 (7) ◽  
pp. 615-623 ◽  
Author(s):  
Xin Shun Ding ◽  
Stanislaw Flasinski ◽  
Richard S. Nelson
Keyword(s):  
Mosaic Virus ◽  
Systemic Infection ◽  
Cell Types ◽  
Brome Mosaic Virus ◽  
Temperature Dependent ◽  
Mesophyll Cells ◽  
Bundle Sheath Cells ◽  
The Relationship ◽  
Dependent Mechanism

Results from previous cytological studies on barley (Hordeum vulgare) infected with brome mosaic virus (BMV) indicated that this virus can infect and accumulate to high levels in mesophyll and other cell types within the leaves. Through immunocytochemistry and in situ hybridization, we have determined that BMV infection in barley is restricted predominantly to cells within and associated with vasculature when plants are grown at 24/20°C (day/night). This tissue restriction can be fully overcome by growing infected plants at 34°C for 2 h. Our results also indicate that BMV is likely to start systemic infection of young, uninoculated leaves in barley before spreading into all longitudinal veins in inoculated leaves. Possible barrier(s) to BMV movement between vascular bundle sheath cells and mesophyll cells, and the relationship between virus and photoassimilate transport through longitudinal and transverse veins are discussed.

scholarly journals Cucumber mosaic virus Establishes Systemic Infection at Increased Temperature Following Viral Entrance Into the Phloem Pathway of Tetragonia expansa

2003 ◽  
Vol 93 (11) ◽  
pp. 1445-1451 ◽  
Author(s):  
Takashi Kobori ◽  
Takeshi Osaki ◽  
Satoshi T. Ohki
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Cell Movement ◽  
Systemic Infection ◽  
Regulatory Site ◽  
Mesophyll Cells ◽  
Increased Temperature ◽  
Tetragonia Expansa ◽  
Internal Phloem

A potential regulatory site for Cucumber mosaic virus (CMV, pepo strain) movement necessary to establish systemic infection was identified through immunological and hybridization studies on Tetragonia expansa, which was systemically infected by CMV at 36°C but not at 24°C. In inoculated leaves, cell-to-cell movement of CMV was enhanced at 36°C compared with that observed at 24°C. CMV was distributed in the phloem cells of minor veins as well as epidermal and mesophyll cells at both 36 and 24°C. CMV was detected in the petioles of inoculated leaves, stems, and petioles of uninoculated upper leaves at 36°C, whereas CMV was detected only in the petioles of inoculated leaves and in stems at 24°C. CMV moved into the phloem and was transported to the stem within 24 h postinoculation (hpi) at 36°C. However, it did not accumulate in the petioles of the upper leaves until 36 hpi. In petioles of inoculated leaves at 24°C, CMV was detected in the external phloem but not in the internal phloem. From these results, we conclude that systemic infection is established after viral entrance into the phloem pathway in T. expansa at 36°C.

scholarly journals miR-375 mediates CRH signaling pathway in inhibiting E2 synthesis in porcine ovary

Reproduction ◽  
2017 ◽  
Vol 153 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Chulin Yu ◽  
Meiling Li ◽  
Yue Wang ◽  
Ying Liu ◽  
Chengzhi Yan ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Granulosa Cells ◽  
Reproductive System ◽  
Follicular Development ◽  
Cell Types ◽  
Signaling System ◽  
Key Factor ◽  
The Relationship

The corticotropin-releasing hormone (CRH) signaling system is involved in numbers of stress-related physiological and pathological responses, including its inhibiting effects on estradiol (E2) synthesis and follicular development in the ovary. In addition, there are reports that microRNAs (miRNAs) can control the function of animal reproductive system. The aim of present study was to investigate the functions of miR-375 and the relationship between miR-375 and CRH signaling molecules in the porcine ovary. First, our common PCR results show that miR-375 and the CRH receptor 1 (CRHR1) are expressed in porcine ovary, whereas CRH receptor 2 (CRHR2) is not detected. We further have located the cell types of miR-375 and CRHR1 by in situ hybridization (ISH), and the results show that miR-375 is located only in the granulosa cells, whereas CRHR1 is positive in all of granulosa cells and oocytes, inferring that miR-375 and CRHR1 are co-localized in granulosa cells. Second, we show that overexpression of miR-375 in cultured granulosa cells suppresses the E2 production, whereas miR-375 knockdown demonstrates the opposite result. Besides, our in vitro results demonstrate that miR-375 mediates the signaling pathway of CRH inhibiting E2 synthesis. Finally, our data show that the action of miR-375 is accomplished by directly binding to the 3′UTR of specificity protein1 (SP1) mRNA to decrease the SP1 protein level. Thus, we conclude that miR-375 is a key factor in regulating E2 synthesis by mediating the CRH signaling pathway.

scholarly journals Characterization of a Brome mosaic virus Strain and Its Use as a Vector for Gene Silencing in Monocotyledonous Hosts

2006 ◽  
Vol 19 (11) ◽  
pp. 1229-1239 ◽  
Author(s):  
Xin Shun Ding ◽  
William L. Schneider ◽  
Srinivasa Rao Chaluvadi ◽  
M. A. Rouf Mian ◽  
Richard S. Nelson
Keyword(s):  
Gene Silencing ◽  
Mosaic Virus ◽  
Gene Function ◽  
Festuca Arundinacea ◽  
Systemic Infection ◽  
Brome Mosaic Virus ◽  
Expression Vectors ◽  
Virus Induced Gene Silencing ◽  
Dicotyledonous Plants ◽  
Virus Expression

Virus-induced gene silencing (VIGS) is used to analyze gene function in dicotyledonous plants but less so in monocotyledonous plants (particularly rice and corn), partially due to the limited number of virus expression vectors available. Here, we report the cloning and modification for VIGS of a virus from Festuca arundinacea Schreb. (tall fescue) that caused systemic mosaic symptoms on barley, rice, and a specific cultivar of maize (Va35) under greenhouse conditions. Through sequencing, the virus was determined to be a strain of Brome mosaic virus (BMV). The virus was named F-BMV (F for Festuca), and genetic determinants that controlled the systemic infection of rice were mapped to RNAs 1 and 2 of the tripartite genome. cDNA from RNA 3 of the Russian strain of BMV (R-BMV) was modified to accept inserts from foreign genes. Coinoculation of RNAs 1 and 2 from F-BMV and RNA 3 from R-BMV expressing a portion of a plant gene to leaves of barley, rice, and maize plants resulted in visual silencing-like phenotypes. The visual phenotypes were correlated with decreased target host transcript levels in the corresponding leaves. The VIGS visual phenotype varied from maintained during silencing of actin 1 transcript expression to transient with incomplete penetration through affected tissue during silencing of phytoene desaturase expression. F-BMV RNA 3 was modified to allow greater accumulation of virus while minimizing virus pathogenicity. The modified vector C-BMVA/G (C for chimeric) was shown to be useful for VIGS. These BMV vectors will be useful for analysis of gene function in rice and maize for which no VIGS system is reported.

scholarly journals Virus Recovery Is Induced in Brome mosaic virus p2 Transgenic Plants Showing Synchronous Complementation and RNA-2-Specific Silencing

2000 ◽  
Vol 13 (3) ◽  
pp. 247-258 ◽  
Author(s):  
Lakshminarayan M. Iyer ◽  
Timothy C. Hall
Keyword(s):  
Transgenic Plants ◽  
Mosaic Virus ◽  
Brome Mosaic Virus ◽  
Degradation Rates ◽  
Class 1 ◽  
Steady State Levels ◽  
Context Specific ◽  
Virus Recovery ◽  
Specific Degradation ◽  
The Relationship

Nicotiana benthamiana plants expressing Brome mosaic virus (BMV) p2 protein complemented replication of RNAs1+3 but, surprisingly, supported little or no replication of RNA-2. Despite this, the p2 transgenic plants were able to support systemic migration of RNAs-1 and -3. Kinetic analyses showed identical degradation rates for RNAs-2 and -3, greatly detracting from the concept of an induction of an RNA-2-specific degradation system. Deletion analysis identified a 200-nucleotide sequence that may contribute to silencing in a context-specific manner. When (R)1 progeny of a severely silencing p2 transgenic line were tested for virus resistance, three different classes of reactions were observed. In class 1 and class 3 plants, the virus moved systemically and showed various extents of RNA-2 silencing. However, in class 2 plants, there was a stochastic onset of post-transcriptional silencing in the systemic leaves that was reminiscent of virus recovery. Plants showing recovery tended to have a greater number of transgene loci than did those exhibiting componentspecific silencing. The induction of silencing did not appear to be dependent solely on the combined steady state levels of the transgene and viral RNA. Some plants transformed with a p2 frameshift construct showed a complete silencing phenotype, but none showed RNA-2-specific silencing. While the relationship between the two types of silencing remains unclear, we speculate that our observations reflect early events in the induction of virus recovery.

scholarly journals Changes in IGFs in cardiac tissue following myocardial infarction

1999 ◽  
Vol 163 (3) ◽  
pp. 433-445 ◽  
Author(s):  
KG Matthews ◽  
GP Devlin ◽  
JV Conaglen ◽  
SP Stuart ◽  
W Mervyn Aitken ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Binding Proteins ◽  
Cardiac Tissue ◽  
Apoptotic Cell ◽  
Specific Binding ◽  
Cell Types ◽  
Necrotic Tissue ◽  
Igf I ◽  
The Relationship

We have studied changes in the IGF axis in an ovine model of myocardial infarction (MI), in order to determine the relationship between time-based changes in post-infarct myocardium and IGF levels. IGF localization was studied by immunocytochemistry, production by in situ hybridization, and specific binding by radioligand studies. In surviving tissue, IGF-I peptide localized to cardiomyocytes, with strongest immunostaining at 1 and 2 days post-infarct in the immediate border area adjoining the infarct, where IGF-I mRNA also increased, reaching a maximum at 2 days. Binding of radiolabelled IGF-I in surviving tissue was initially lower than that seen in cardiomyocytes in control myocardium, subsequently increasing to become significantly greater by 6 days post-infarct. In necrotic tissue, IGF-I peptide was still detectable in cardiomyocytes at 0.5 days post-infarct, but had cleared from this area by 1 day, becoming detectable again at 6 days post-infarct in macrophages and fibroblasts infiltrating the repair zone. IGF-I mRNA was not detected in necrotic tissue until 6 days, when probe hybridized to macrophages and fibroblasts. Within the necrotic zone, high levels of radiolabelled IGF-I binding to a combination of receptors and binding proteins were observed in cardiomyocytes in islands of viable tissue located close to the border. Weak immunostaining for IGF-II was observed in cardiomyocytes of the surviving tissue. IGF-II mRNA was not detected in either surviving or necrotic areas. Binding of radiolabelled IGF-II was predominantly to macrophages in both surviving and infarct areas, although as with IGF-I, high levels of binding of radiolabelled IGF-II to a combination of receptors and binding proteins were observed in islands of viable tissue close to the border within the necrotic area. We conclude that, following MI, surviving cardiomyocytes at the infarct border show marked changes in IGF-I localization, production, and specific binding, indicating that the IGF axis is directly involved in post-infarct events, possibly in the maintenance of cardiac function by the induction of hypertrophy and in cell survival by decreasing apoptotic cell death, which has been demonstrated in other cell types.

scholarly journals Electron Probe Microanalysis of Potassium and Chloride in Freeze-Substituted Leaf Sections of Zea Mays

1973 ◽  
Vol 26 (5) ◽  
pp. 1015 ◽  
Author(s):  
CK Pallaghy
Keyword(s):  
Potassium Concentration ◽  
Cell Types ◽  
Bundle Sheath ◽  
Concentration Gradients ◽  
Mesophyll Cells ◽  
Transmission Electron ◽  
Bundle Sheath Cells ◽  
Scanning Transmission ◽  
Diamond Knife ◽  
Sheath Cells

Small sections of leaves were floated on distilled water under either light or dark conditions, and were freeze-substituted in a 1 % solution of osmium tetroxide in acetone at -78�C followed by embedding in an epoxy resin. Approximately I-11m-thick sections were cut using a dry diamond knife and examined by scanning transmission electron microscopy. The relative concentrations of potassium and chloride in subcellular compartments were determined using an energy dispersive X-ray analyser. The concentration of sodium in the leaf (1�7 m-equivjkg of wet tissue) was too low to be detected by this method. The spatial resolution of this technique was sufficient to distinguish between concentrations in the chloroplasts, cytoplasm, vacuole, and nuclei. The concentration of chloride in stomata and some other epidermal cells was very much higher than in either mesophyll or bundle sheath cells. The potassium concentration in some vascular cells was at least two- to threefold higher than that in mesophyll or bundle sheath cells. The Cl : K ratio in mesophyll and bundle sheath cells resembled that in the solution (0 �10) used for growing the plants. The concentration of chloride in the "free" cytoplasm of mesophyll cells was always very low. Significant differences were found in the "ion" relations of mesophyll and bundle sheath cells. Whereas the ratio of potassium concentration between the vacuole and chloroplasts of mesophyll cells was high (1 �19) in the light and low (0�65) in the dark, the opposite was true for bundle sheath cells-O� 65 and 0�86 respectively. The ratio of potassium concentration between the vacuo les of mesophyll and those of bundle sheath cells was 1 �48 in the light, but only 0�76 in the dark. These concentration gradients are discussed in relation to a possible transfer of organic acid salts of potassium between these two cell types.

scholarly journals Detection of phosphoenolpyruvate and ribulose 1,5-bisphosphate carboxylase transcripts in maize leaves by in situ hybridization with sulfonated cDNA probes.

1989 ◽  
Vol 37 (4) ◽  
pp. 423-428 ◽  
Author(s):  
C Perrot-Rechenmann ◽  
M Joannes ◽  
D Squalli ◽  
P Lebacq
Keyword(s):  
In Situ Hybridization ◽  
Cell Types ◽  
Small Subunit ◽  
Bundle Sheath ◽  
Differential Distribution ◽  
Mesophyll Cells ◽  
Bisphosphate Carboxylase ◽  
Maize Leaves ◽  
Specific Mrnas

This report outlines an efficient in situ hybridization method for locating specific mRNAs in tissue cryosections using sulfonated cDNA probes. The method involves chemical modification of DNA probes by insertion of a sulfone radical on cytosine residues, which generates a specific epitope. Sulfonated DNA is then detected by using indirect immunochemical procedure. Alternatively, antibodies conjugated to fluorescein or to alkaline phosphatase were used for mRNA detection. In situ hybridization was developed to study aspects of mesophyll and bundle sheath cell differentiation in maize leaves. Our results indicate that phosphoenolpyruvate carboxylase (PEP C) mRNA is restricted to mesophyll cells, and the nucleus-encoded mRNA of the small subunit (SSU) ribulose 1,5-bisphosphate carboxylase (RuBP C) is limited to the cytosol of bundle sheath cells. Thus, using in situ hybridization, we have demonstrated that the differential distribution of PEP C and RuBP C proteins in the two cell types also reflects the location of their mRNAs. These data imply either a tissue-specific transcriptional regulation or a selective mRNA degradation.

bundle sheath defective, a mutation that disrupts cellular differentiation in maize leaves

Development ◽  
1994 ◽  
Vol 120 (3) ◽  
pp. 673-681 ◽  
Author(s):  
J. A. Langdale ◽  
C. A. Kidner
Keyword(s):  
Gene Action ◽  
Morphological Differentiation ◽  
Cell Types ◽  
Bundle Sheath ◽  
Sheath Cell ◽  
Mesophyll Cells ◽  
Bundle Sheath Cell ◽  
Bundle Sheath Cells ◽  
Maize Leaves ◽  
Sheath Cells

Post-primordial differentiation events in developing maize leaves produce two photosynthetic cell types (bundle sheath and mesophyll) that are morphologically and biochemically distinct. We have isolated a mutation that disrupts the differentiation of one of these cell types in light-grown leaves. bundle sheath defective 1-mutable 1 (bsd1-m1) is an unstable allele that was induced by transposon mutagenesis. In the bundle sheath cells of bsd1-m1 leaves, chloroplasts differentiate aberrantly and C4 photosynthetic enzymes are absent. The development of mesophyll cells is unaffected. In dark-grown bsd1-m1 seedlings, morphological differentiation of etioplasts is only disrupted in bundle sheath cells but photosynthetic enzyme accumulation patterns are altered in both cell types. These data suggest that, during normal development, the Bsd1 gene directs the morphological differentiation of chloroplasts in a light-independent and bundle sheath cell-specific fashion. In contrast, Bsd1 gene action on photosynthetic gene expression patterns is cell-type independent in the dark (C3 state) but bundle sheath cell-specific in the light (C4 state). Current models hypothesize that C4 photosynthetic differentiation is achieved through a light-induced interaction between bundle sheath and mesophyll cells (J. A. Langdale and T. Nelson (1991) Trends in Genetics 7, 191–196). Based on the data shown in this paper, we propose that induction of the C4 state restricts Bsd1 gene action to bundle sheath cells.

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