scholarly journals Studies on the effect of sodium arsenate & cadmium chloride on Pithophora oedogonia (Mont.) Wittrock 1877

2021 ◽  
pp. 80-84
Author(s):  
Puspendu Karmakar ◽  
Jai Prakash Keshri
Keyword(s):  
Cadmium Chloride ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Anthropogenic Factors ◽  
Chlorophyll B ◽  
Sodium Arsenate ◽  
Carotenoid Production ◽  
Abrupt Changes ◽  
Control Set ◽  
Cdcl2 Treatment

Cadmium and Arsenic are heavy metals although not common in our environment, its threat in certain places are aggravated due to anthropogenic factors. To know its critical role on plants the investigation was made using Na2HAsO4 and CdCl2 treatment on Pithophora oedogonia (Mont.) Wittrock 1877. The observations were made after 14 days of treatment. The changes were noted. In both cases, the treated cells exhibited gradual disruption of cell wall and cell membrane. The chlorophyll content initially increased and finally decreased due to the notable destruction of chloroplasts in both treated cells. A profuse number of akinetes were observed at 100 ppm and 150 ppm of Na2HAsO4 and CdCl2 treated media. Decrease in protein content was started at 100 ppm in both cases. The lipid content initially decreased at 50 ppm and at 100 ppm lipid profile increased in terms of toleration to the Na2HAsO4 and CdCl2 stress. Pithophora oedogonia (Mont.) Wittrock 1877 exhibited more sensitivity to CdCl2 stress & showing abrupt changes in chlorophyll-a and chlorophyll-b production. The carotenoid production shown more sensitivity in Na2HAsO4 stress. Total phenol production was decreased initially and at 200 ppm CdCl2 stress had shown significant enhancement than the control set but at the 200 ppm of Na2HAsO4 shown inhibitory effect.

scholarly journals Elongation of the Cytoplasmic Tail Interferes with the Fusion Activity of Influenza Virus Hemagglutinin

1998 ◽  
Vol 72 (5) ◽  
pp. 3554-3559 ◽  
Author(s):  
Masanobu Ohuchi ◽  
Christian Fischer ◽  
Reiko Ohuchi ◽  
Astrid Herwig ◽  
Hans-Dieter Klenk
Keyword(s):  
Intracellular Transport ◽  
Critical Role ◽  
Simian Virus 40 ◽  
Cytoplasmic Tail ◽  
Surface Expression ◽  
Inhibitory Effect ◽  
Simian Virus ◽  
Cell Surface Expression ◽  
Erythrocyte Membranes ◽  
Fusion Pores

ABSTRACT The hemagglutinin (HA) of fowl plague virus was lengthened and shortened by site-specific mutagenesis at the cytoplasmic tail, and the effects of these modifications on HA functions were analyzed after expression from a simian virus 40 vector. Elongation of the tail by the addition of one to six histidine (His) residues did not interfere with intracellular transport, glycosylation, proteolytic cleavage, acylation, cell surface expression, and hemadsorption. However, the ability to induce syncytia at a low pH decreased dramatically depending on the number of His residues added. Partial fusion (hemifusion), assayed by fluorescence transfer from octadecylrhodamine-labeled erythrocyte membranes, was also reduced, but even with the mutant carrying six His residues, significant transfer was observed. However, when the formation of fusion pores was examined with hydrophilic fluorescent calcein, transfer from erythrocytes to HA-expressing cells was not observed with the mutant carrying six histidine residues. The addition of different amino acids to the cytoplasmic tail of HA caused an inhibitory effect similar to that caused by the addition of His. On the other hand, a mutant lacking the cytoplasmic tail was still able to fuse at a reduced level. These results demonstrate that elongation of the cytoplasmic tail interferes with the formation and enlargement of fusion pores. Thus, the length of the cytoplasmic tail plays a critical role in the fusion process.

scholarly journals Effect of kinetin on nucleic acid synthesis in senescing and young leaves in Brassica oleracea L. var. gongylodes L.

2015 ◽  
Vol 44 (4) ◽  
pp. 553-565
Author(s):  
J. Legocka ◽  
A. Szweykowska
Keyword(s):  
Molecular Weight ◽  
Nucleic Acid ◽  
Acid Synthesis ◽  
Inhibitory Effect ◽  
Rrna Synthesis ◽  
Low Molecular Weight ◽  
Chlorophyll B ◽  
Mature Leaves ◽  
Young Leaves ◽  
Brassica Oleracea L

In detached kohlrabi leaves senescing in the dark, the decrease in chlorophyll to was more pronounced than in chlorophyll a. The retardation by kinetin of the chlorophyll loss was also markedly stronger in the case of chlorophyll b. Using the fractionation of nucleic acids on polyacrylamide gels it has been shown that during leaf senescence the level of all RNA species decreased, whereas the amount of DNA was more or less constant. In the presence of kinetin, the loss of RNA was inhibited and the incorporation of precursor into the cytoplasmic rRNA as well as into low molecular weight RNA species was supported. Chloroplast rRNA synthesis has not been detected in mature leaves and kinetin showed no effect in this respect. In young expanding leaves detached and kept in light, the synthesis of cytoplasmic rRNA was strongly stimulated by kinetin, whereas in the case of Chloroplast rRNA only an inhibitory effect of kinetin could be found. The results suggest that the cytokinins are primarily involved in processes of the synthesis of cytoplasmic rRNA and low molecular RNA fractions, and in this way affect the development of plastids, in particular the course of their senescence.

scholarly journals Rapid G protein-regulated activation event involved in lymphocyte binding to high endothelial venules.

1993 ◽  
Vol 178 (1) ◽  
pp. 367-372 ◽  
Author(s):  
R F Bargatze ◽  
E C Butcher
Keyword(s):  
G Protein ◽  
Pertussis Toxin ◽  
Critical Role ◽  
Lymphocyte Activation ◽  
Inhibitory Effect ◽  
Peyer's Patches ◽  
Peyer’S Patches ◽  
High Endothelial Venules ◽  
Activation Event

The homing of blood borne lymphocytes into lymph nodes and Peyer's patches is mediated in part by recognition and binding to specialized high endothelial venules (HEV). Here we demonstrate that a rapid pertussis toxin-sensitive lymphocyte activation event can participate in lymphocyte recognition of HEV. In situ video microscopic analyses of lymphocyte interactions with HEV in exteriorized mouse Peyer's patches reveal that pertussis toxin has no effect on an initial "rolling" displayed by many lymphocytes, but inhibits an activation-dependent "sticking" event required for lymphocyte arrest. This is the first demonstration that physiologic lymphocyte-endothelial interactions can involve sequential rolling, activation, and activation-dependent arrest, previously shown only for neutrophils. The inhibitory effect of the toxin is dependent on its G protein-modifying ADP-ribosyltransferase activity and can be reversed by phorbol myristic acetate, which bypasses cell surface receptors to trigger activation-dependent adhesion. Lymphocyte sticking can occur within 1-3 s after initiation of rolling. We conclude that a rapid receptor-mediated activation event involving G protein signaling can trigger stable lymphocyte attachment to HEV in vivo, and may play a critical role in regulating lymphocyte homing.

PDGF-AA and its receptor influence early lung branching via an epithelial-mesenchymal interaction

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2559-2567 ◽  
Author(s):  
P. Souza ◽  
M. Kuliszewski ◽  
J. Wang ◽  
I. Tseu ◽  
A.K. Tanswell ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Critical Role ◽  
Polymerase Chain Reaction Analysis ◽  
Branching Morphogenesis ◽  
Inhibitory Effect ◽  
Embryonic Lung ◽  
Morphometric Analyses ◽  
Terminal Buds ◽  
Lung Branching

The biological role of platelet-derived growth factor (PDGF)-AA in lung morphogenesis was investigated by incubating embryonic lung explants with phosphorothioate antisense PDGF-A oligonucleotides, which decreased PDGF-AA but not PDGF-BB protein content. Antisense PDGF-A oligonucleotides inhibited DNA synthesis. This inhibitory effect of antisense PDGF-A was reversed by the addition of exogenous PDGF-AA but not PDGF-BB. Morphometric analyses of antisense-treated cultures showed a significant reduction in lung size. The number of terminal buds of the lung explants was significantly decreased by antisense PDGF-A oligonucleotides. PDGF-AA but not PDGF-BB attenuated the inhibitory effect of antisense PDGF-A on early lung branching. Sense PDGF-A had no effect on DNA synthesis and early lung branching. Reverse transcriptase-polymerase chain reaction analysis revealed PDGF-A mRNA expression in the epithelial component of the embryonic lung, while message for PDGF alpha-receptor was expressed in the mesenchyme. Incubation of explants with neutralizing PDGF-AA antibodies also reduced DNA synthesis and early branching morphogenesis. We conclude that PDGF-AA and its receptor represent an important epithelial-mesenchymal interaction which plays a critical role in early lung branching morphogenesis.

scholarly journals CD16+ monocytes control T-cell subset development in immune thrombocytopenia

Blood ◽  
2012 ◽  
Vol 120 (16) ◽  
pp. 3326-3335 ◽  
Author(s):  
Hui Zhong ◽  
Weili Bao ◽  
Xiaojuan Li ◽  
Allison Miller ◽  
Caroline Seery ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Thrombocytopenia ◽  
Critical Role ◽  
Cell Subset ◽  
Inhibitory Effect ◽  
Cell Polarization ◽  
T Cell Subsets ◽  
Monocyte Subset ◽  
Th Cells ◽  
Ifn Γ

Abstract Immune thrombocytopenia (ITP) results from decreased platelet production and accelerated platelet destruction. Impaired CD4+ regulatory T-cell (Treg) compartment and skewed Th1 and possibly Th17 responses have been described in ITP patients. The trigger for aberrant T-cell polarization remains unknown. Because monocytes have a critical role in development and polarization of T-cell subsets, we explored the contribution of monocyte subsets in control of Treg and Th development in patients with ITP. Unlike circulating classic CD14hiCD16− subpopulation, the CD16+ monocyte subset was expanded in ITP patients with low platelet counts on thrombopoietic agents and positively correlated with T-cell CD4+IFN-γ+ levels, but negatively with circulating CD4+CD25hiFoxp3+ and IL-17+ Th cells. Using a coculture model, we found that CD16+ ITP monocytes promoted the expansion of IFN-γ+CD4+ cells and concomitantly inhibited the proliferation of Tregs and IL-17+ Th cells. Th-1–polarizing cytokine IL-12, secreted after direct contact of patient T-cell and CD16+ monocytes, was responsible for the inhibitory effect on Treg and IL-17+CD4+ cell proliferation. Our findings are consistent with ITP CD16+ monocytes promoting Th1 development, which in turn negatively regulates IL-17 and Treg induction. This underscores the critical role of CD16+ monocytes in the generation of potentially pathogenic Th responses in ITP.

Degradation of soluble VEGF receptor-1 by MMP-7 allows VEGF access to endothelial cells

Blood ◽  
2009 ◽  
Vol 113 (10) ◽  
pp. 2363-2369 ◽  
Author(s):  
Ta-Kashi Ito ◽  
Genichiro Ishii ◽  
Seiji Saito ◽  
Keiichi Yano ◽  
Ayuko Hoshino ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Tube Formation ◽  
Membrane Receptors ◽  
Vegf Receptor ◽  
Migration Assay ◽  
Vegf Inhibitor ◽  
Umbilical Vein Endothelial Cells

AbstractVascular endothelial growth factor (VEGF) signaling in endothelial cells serves a critical role in physiologic and pathologic angiogenesis. Endothelial cells secrete soluble VEGF receptor-1 (sVEGFR-1/sFlt-1), an endogenous VEGF inhibitor that sequesters VEGF and blocks its access to VEGF receptors. This raises the question of how VEGF passes through this endogenous VEGF trap to reach its membrane receptors on endothelial cells, a step required for VEGF-driven angiogenesis. Here, we show that matrix metalloproteinase-7 (MMP-7) degrades human sVEGFR-1, which increases VEGF bioavailability around the endothelial cells. Using a tube formation assay, migration assay, and coimmunoprecipitation assay with human umbilical vein endothelial cells (HUVECs), we show that the degradation of sVEGFR-1 by MMP-7 liberates the VEGF165 isoform from sVEGFR-1. The presence of MMP-7 abrogates the inhibitory effect of sVEGFR-1 on VEGF-induced phosphorylation of VEGF receptor-2 on HUVECs. These data suggest that VEGF escapes the sequestration by endothelial sVEGFR-1 and promotes angiogenesis in the presence of MMP-7.

Role of phosphoinositide 3-kinase β in platelet aggregation and thromboxane A2 generation mediated by Gi signalling pathways

2010 ◽  
Vol 429 (2) ◽  
pp. 369-377 ◽  
Author(s):  
Analia Garcia ◽  
Soochong Kim ◽  
Kamala Bhavaraju ◽  
Simone M. Schoenwaelder ◽  
Satya P. Kunapuli
Keyword(s):  
Platelet Aggregation ◽  
Critical Role ◽  
Thromboxane A2 ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
P2y12 Receptor ◽  
Functional Responses ◽  
Induce Platelet Aggregation ◽  
Erk Phosphorylation

PI3Ks (phosphoinositide 3-kinases) play a critical role in platelet functional responses. PI3Ks are activated upon P2Y12 receptor stimulation and generate pro-aggregatory signals. P2Y12 receptor has been shown to play a key role in the platelet aggregation and thromboxane A2 generation caused by co-stimulation with Gq or Gz, or super-stimulation of Gi pathways. In the present study, we evaluated the role of specific PI3K isoforms α, β, γ and δ in platelet aggregation, thromboxane A2 generation and ERK (extracellular-signal-regulated kinase) activation. Our results show that loss of the PI3K signal impaired the ability of ADP to induce platelet aggregation, ERK phosphorylation and thromboxane A2 generation. We also show that Gq plus Gi- or Gi plus Gz-mediated platelet aggregation, ERK phosphorylation and thromboxane A2 generation in human platelets was inhibited by TGX-221, a PI3Kβ-selective inhibitor, but not by PIK75 (a PI3Kα inhibitor), AS252424 (a PI3Kγ inhibitor) or IC87114 (a PI3Kδ inhibitor). TGX-221 also showed a similar inhibitory effect on the Gi plus Gz-mediated platelet responses in platelets from P2Y1−/− mice. Finally, 2MeSADP (2-methyl-thio-ADP)-induced Akt phosphorylation was significantly inhibited in the presence of TGX-221, suggesting a critical role for PI3Kβ in Gi-mediated signalling. Taken together, our results demonstrate that PI3Kβ plays an important role in ADP-induced platelet aggregation. Moreover, PI3Kβ mediates ADP-induced thromboxane A2 generation by regulating ERK phosphorylation.

scholarly journals Blocking Both E-Selectin and P-Selectin Inhibits Neutrophil Recruitment into the Murine Testis after Ischemia-Reperfusion-Induced Injury

2008 ◽  
Vol 77 (3) ◽  
pp. 321-326 ◽  
Author(s):  
M. Celebi ◽  
A. G. A. Paul
Keyword(s):  
Flow Cytometry ◽  
Germ Cell ◽  
Adhesion Molecules ◽  
Testicular Torsion ◽  
Matched Control ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Neutrophil Recruitment ◽  
Testicular Interstitial Cells

Ischemia-reperfusion (IR) injury of the testis results in germ cell specific apoptosis, a process in which neutrophil recruitment to the testes plays a critical role. Adhesion molecules, in particular E- and P-selectins, play a critical role in this recruitment. The present study sought to characterize the inhibitory effect of function-blocking monoclonal anti-mouse E- and P-selectin antibodies on the migration of neutrophils into the IR-induced testis of the mouse. Mice were subjected to a 2 hr period of testicular torsion (ischemia) followed by detorsion (reperfusion). Ten minutes after the onset of reperfusion mice received either a mixture of 200 μg function-blocking monoclonal E-selectin and P-selectin antibody (FBMAb group; 100 μg; each) intravenously or 200 μg of isotype-matched control-antibody (IMCAb group). Separate groups of mice underwent shamoperation (SO group) or received 500 ng of TNFα (IF group) to induce inflammation. Mice were sacrificed 24 h after reperfusion and testicular interstitial cells were isolated and analyzed for the presence of neutrophils by means of flow cytometry. The mixture of function-blocking monoclonal E- and P-selectin antibody (FBMAb) decreased neutrophil recruitment to the IR-induced testis significantly (FBMAb group as compared to the IMCAb group 20.2 ± 2.8 vs. 51.9 ± 4.0 % Gr-1+CD11b+ of total leukocytes; p = 0.0002). Therefore, blocking both E- and P-selectin may be therapeutically beneficial to protect postischemic testis.

scholarly journals Reciprocal Regulation between Primary Cilia and mTORC1

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 711 ◽  
Author(s):  
Yandong Lai ◽  
Yu Jiang
Keyword(s):  
Primary Cilia ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Reciprocal Regulation ◽  
Quiescent Cells ◽  
Mechanistic Target Of Rapamycin ◽  
Tumor Suppressor Proteins ◽  
Mtorc1 Signaling ◽  
Liver Kinase B1 ◽  
Amp Activated Protein Kinase

In quiescent cells, primary cilia function as a mechanosensor that converts mechanic signals into chemical activities. This unique organelle plays a critical role in restricting mechanistic target of rapamycin complex 1 (mTORC1) signaling, which is essential for quiescent cells to maintain their quiescence. Multiple mechanisms have been identified that mediate the inhibitory effect of primary cilia on mTORC1 signaling. These mechanisms depend on several tumor suppressor proteins localized within the ciliary compartment, including liver kinase B1 (LKB1), AMP-activated protein kinase (AMPK), polycystin-1, and polycystin-2. Conversely, changes in mTORC1 activity are able to affect ciliogenesis and stability indirectly through autophagy. In this review, we summarize recent advances in our understanding of the reciprocal regulation of mTORC1 and primary cilia.

scholarly journals Mutations in the Cytoplasmic Domain of a Paramyxovirus Fusion Glycoprotein Rescue Syncytium Formation and Eliminate the Hemagglutinin-Neuraminidase Protein Requirement for Membrane Fusion

2003 ◽  
Vol 77 (1) ◽  
pp. 167-178 ◽  
Author(s):  
Shaguna Seth ◽  
Annelet Vincent ◽  
R. W. Compans
Keyword(s):  
Membrane Fusion ◽  
Critical Role ◽  
Syncytium Formation ◽  
Inhibitory Effect ◽  
Simian Virus ◽  
Dependent Manner ◽  
Fusion Activity ◽  
Double Mutation ◽  
F Protein ◽  
Fusion Glycoprotein

ABSTRACT SER virus is closely related to the paramyxovirus simian virus 5 (SV5) but is defective in syncytium formation. The SER virus F protein has a long cytoplasmic tail (CT) domain that has been shown to inhibit membrane fusion, and this inhibitory effect could be eliminated by truncation of the C-terminal sequence (S. Tong, M. Li, A. Vincent, R. W. Compans, E. Fritsch, R. Beier, C. Klenk, M. Ohuchi, and H.-D. Klenk, Virology 301:322-333, 2002). To study the sequence requirements for regulation of fusion, codons for SER virus F protein residues spanning amino acids 535 to 542 and 548 were mutated singly to alanines, and the two leucine residues at positions 539 and 548 were mutated doubly to alanines. We found that leu-539 and leu-548 in the CT domain played a critical role in the inhibition of fusion, as mutation of the two leucines singly to alanines partially rescued fusion, and the double mutation L539, 548A completely rescued syncytium formation. Mutation of charged residues to alanines had little effect on the suppression of fusion activity, whereas the mutation of serine residues to alanines enhanced fusion activity significantly. The L539, 548A mutant also showed extensive syncytium formation when expressed without the SER virus HN protein. By constructing a chimeric SV5-SER virus F CT protein, we also found that the inhibitory effect of the long CT of the SER virus F protein could be partially transferred to the SV5 F protein. These results demonstrate that an elongated CT of a paramyxovirus F protein interferes with membrane fusion in a sequence-dependent manner.

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