scholarly journals Systematic analysis of specific and nonspecific auxin effects on endocytosis and trafficking

2021 ◽  
Author(s):  
Madhumitha Narasimhan ◽  
Michelle Gallei ◽  
Shutang Tan ◽  
Alexander Johnson ◽  
Inge Verstraeten ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Specific Effect ◽  
Brefeldin A ◽  
Naphthalene Acetic Acid ◽  
Systematic Analysis ◽  
Low Concentrations ◽  
Nonspecific Effects ◽  
High Auxin ◽  
Golgi Network ◽  
Directional Transport

Abstract The phytohormone auxin and its directional transport through tissues are intensively studied. However, a mechanistic understanding of auxin-mediated feedback on endocytosis and polar distribution of PIN auxin transporters remains limited due to contradictory observations and interpretations. Here, we used state-of-the-art methods to reexamine the auxin effects on PIN endocytic trafficking. We used high auxin concentrations or longer treatments versus lower concentrations and shorter treatments of natural indole-3-acetic acid (IAA) and synthetic naphthalene acetic acid (NAA) auxins to distinguish between specific and nonspecific effects. Longer treatments of both auxins interfere with Brefeldin A-mediated intracellular PIN2 accumulation and also with general aggregation of endomembrane compartments. NAA treatment decreased the internalization of the endocytic tracer dye, FM4-64; however, NAA treatment also affected the number, distribution, and compartment identity of the early endosome/trans-Golgi network, rendering the FM4-64 endocytic assays at high NAA concentrations unreliable. To circumvent these nonspecific effects of NAA and IAA affecting the endomembrane system, we opted for alternative approaches visualizing the endocytic events directly at the plasma membrane (PM). Using total internal reflection fluorescence microscopy, we saw no significant effects of IAA or NAA treatments on the incidence and dynamics of clathrin foci, implying that these treatments do not affect the overall endocytosis rate. However, both NAA and IAA at low concentrations rapidly and specifically promoted endocytosis of photo-converted PIN2 from the PM. These analyses identify a specific effect of NAA and IAA on PIN2 endocytosis, thus, contributing to its polarity maintenance and furthermore illustrate that high auxin levels have nonspecific effects on trafficking and endomembrane compartments.

Effects of growth-regulating substances on fungi

1969 ◽  
Vol 15 (7) ◽  
pp. 713-721 ◽  
Author(s):  
K. M. Leelavathy
Keyword(s):  
Acetic Acid ◽  
Gibberellic Acid ◽  
Indole Acetic Acid ◽  
Fungal Growth ◽  
Fungal Species ◽  
Naphthalene Acetic Acid ◽  
Low Concentrations ◽  
High Concentrations ◽  
Dichlorophenoxy Acetic Acid ◽  
Fusarium Nivale

The effects of four growth-regulating substances, viz. indole acetic acid, gibberellic acid, 2, 4-dichlorophenoxy acetic acid, and naphthalene acetic acid on the linear growth of Penicillium herquei, Fusarium nivale, Thielavia terricola, and Cunninghamella echinulata were studied. Gibberellic acid at 400 p.p.m. did not reduce fungal growth, whereas the remaining substances at this rate inhibited fungal growth completely. Certain concentrations of the latter substances reduced while others had no influence on growth rate. Gibberellic acid at 1 and 5 p.p.m. was the only substance causing some stimulation of Fusarium nivale. Neither this stimulation nor the inhibition in other cases was constant with regard to growth-regulating substances and fungal species. In general, low concentrations of the growth-regulating substances had no effect on the growth of any of the fungi tested while high concentrations mostly inhibited growth to various extents.

Platelet-Bound Prekallikrein Promotes Pro-Urokinase-Induced Clot Lysis: A Mechanism for Targeting the Factor XII Dependent Intrinsic Pathway of Fibrinolysis

1994 ◽  
Vol 71 (03) ◽  
pp. 347-352 ◽  
Author(s):  
Jean-Pierre Loza ◽  
Victor Gurewich ◽  
Michael Johnstone ◽  
Ralph Pannell
Keyword(s):  
Platelet Rich Plasma ◽  
Specific Inhibitor ◽  
Specific Effect ◽  
Clot Lysis ◽  
Factor Xii ◽  
Intrinsic Pathway ◽  
Clot Retraction ◽  
Enzymatic Mechanism ◽  
Low Concentrations ◽  
Factor Xiia

SummaryClots formed from platelet rich plasma were found to be lysed more readily by low concentrations of pro-urokinase (pro-UK) than clots formed from platelet poor plasma. This was not a non-specific effect since the reverse occurred with tissue plasminogen activator. A mechanical explanation due to platelet-mediated clot retraction was excluded by experiments in which retraction was inhibited with cyto-chalasin B. Therefore, a platelet-mediated enzymatic mechanism was postulated to explain the promotion of fibrinolysis. Casein autography of isolated platelets revealed a ≈ 90 kDa band of activity which comigrated with plasma prekallikrein (PK)/kallikrein, a known activator of pro-UK. Furthermore, treatment of platelets with plasma PK activator (PPA), consisting essentially of factor XIIa, induced activation of pro-UK and of chromomgenic substrate for kallikrein (S-2302). This activity corresponded to approximately 40-200 pM kallikrein per 10 8 washed and gel filtered platelets per ml. The activation of pro-UK by PPA-pretreated platelets was dose-dependent and inhibited by soybean trypsin inhibitor but not by bdellin, a specific inhibitor of plasmin, nor by the corn inhibitor of factor XIIa. Kinetic analysis of pro-UK activation by kallikrein showed promotion of the reaction by platelets. The KM of the reaction was reduced by platelets by ≈ 7-fold, while the kcat was essentially unchanged. In conclusion, PK was shown to be tightly associated with platelets where it can be activated by factor XIIa during clotting. The activation of pro-UK by platelet-bound kallikrein provides an explanation for the observed platelet mediated promotion of pro-UK-induced clot lysis. Since pro-UK and plasminogen have also been shown to be associated with platelets, the present findings suggest a mechanism by which the factor Xlla-dependent intrinsic pathway of fibrinolysis can be localized and targeted to a thrombus.

FTIR, GC-MS and HPLC analysis of Baliospermum montanum (Willd.) Muell. Arg.

2020 ◽  
Vol 11 (4) ◽  
pp. 5059-5066
Author(s):  
Sushma B K ◽  
Raveesha H R
Keyword(s):  
Acetic Acid ◽  
Quantitative Estimation ◽  
Chemical Constituents ◽  
Standard Procedure ◽  
Naphthalene Acetic Acid ◽  
Root Extract ◽  
Pentanoic Acid ◽  
Trimethylsilyl Ester ◽  
Isolation And Characterization ◽  
Ms Analysis

The present work is aimed to determine the chemical constituents in Baliospermum montanum methanolic extracts. An in vitro regenerated procedure was developed for the induction of callus from stem explant cultured on Murashige and Skoog (MS) medium fortified with various concentration and permutations of 2, 4-dichloro phenoxy acetic acid, 1-naphthalene acetic acid, 6-benzyl amino purine and gibberellic acid. FTIR & GC-MS analysis was done according to standard procedure. The quantitative estimation of β-sitosterol was done by HPLC method. Maximum fresh and dry weight of callus was estimated in the combination of GA3 (0.5 mg/L) + NAA (2 mg/L) compared to other concentration. The FTIR analysis showed various functional compounds with different characteristic peak values in the extracts. Major bioactive constituents were recognized in the GC-MS analysis. Root extract revealed the existence of 1-hexadecanol, pentanoic acid, 2-(aminooxy)- and 1-hexacosanol. Leaf extract showed the presence of propanoic acid, 2-oxo-, trimethylsilyl ester, 9,12-octadecadienoic acid (z,z)-, trimethylsilyl ester, docosane, 1,22-dibromo- and pentatriacontane. Stem and stem derived callus exhibit the presence of 1,6,3,4-dihydro-2-deoxy-beta-d-lyxo-hexopyranose, n-hexadecanoic acid and pentanoic acid, 2-(aminooxy). The methanolic extract of leaf exhibited 0.2149 % of β-sitosterol content. There were no peaks observed in the root, stem and stem derived callus. Further studies are necessary for the isolation and characterization of bioactive compounds from B. montanum.

PENGARUH KOMBINASI INTENSITAS NAUNGAN DENGAN ZAT PENGATUR TUMBUH INDOLE BUTIRIC ACID (IBA), NAPHTHALENE ACETIC ACID (NAA), DAN VITAMIN B1 DALAM AKLIMATISASI PERTUMBUHAN BIBIT GAHARU (Aquilaria beccariana)

2013 ◽  
Vol 14 (3) ◽  
Author(s):  
Daru Mulyono
Keyword(s):  
Acetic Acid ◽  
Factorial Design ◽  
Vitamin B1 ◽  
Naphthalene Acetic Acid ◽  
Randomized Design ◽  
Optimal Formula

The objective of this research is to know the optimal formula of Indole Butiric Acid (IBA), Naphthalene Acetic Acid (NAA), Vitamine B1 and the combination with shading intensities to the acclimatization of Gaharu stump (Aquilaria beccariana). This research used Factorial Design with basic analysis of Complete Randomized Design in order to know theeffect of treatment. The research was carried out in Agroindustry and Biotechnology Laboratory, Ciampea, Bogor, from July to September 2007. The results of the research showed that after 8 weeks of treatment: (a). The combination of 55 % shading intensity with IBA 15 mg/l + NAA 10 mg/l + Vitamine B1 1 mg/l was the best formula for increasingheight of Gaharu stump 4.660 cm. (b). The combination of 55 % shading intensity with IBA 15 mg/l + NAA 30 mg/l + Vitamine B1 1 mg/l was the best formula for increasing sum of Gaharu leaf stump 12.337 leafs, (c). The combination of 55 % shading intensity with IBA 15 mg/l + NAA 40 mg/l + Vitamine B1 1 mg/l was the best formula for increasing sumof Gaharu root stump 3.783 roots, and (d). The combination of 55 % shading intensity with IBA 15 mg/l + NAA 40 mg/l + Vitamine B1 1 mg/l was the best formula for increasing length of Gaharu root stump 3.686 cm.

scholarly journals Influence of growth regulators and explants on shoot regeneration in carnation

2009 ◽  
Vol 36 (No. 4) ◽  
pp. 140-146 ◽  
Author(s):  
J.K. Kanwar ◽  
S. Kumar
Keyword(s):  
Acetic Acid ◽  
Shoot Regeneration ◽  
Growth Regulators ◽  
Dianthus Caryophyllus ◽  
Naphthalene Acetic Acid ◽  
Ms Medium ◽  
Shoot Bud ◽  
Dichlorophenoxy Acetic Acid ◽  
Number Of Shoots

The influence of growth regulators, explants and their interactions on in vitro shoot bud formation from callus was studied in <I>Dianthus caryophyllus</I> L. The leaf and internode explants were cultured on Murashige and Skoog (MS) medium containing different concentrations of growth regulators. The highest callus induction was observed with 2 mg/l 2,4-dichlorophenoxy acetic acid (2,4-D) and 1 mg/l benzyl adenine (BA). Out of twenty seven shoot regeneration media tested, only 2 mg/l thidiazuron (TDZ) and zeatin alone or in combination with naphthalene acetic acid (NAA) and/or indole acetic acid (IAA) could differentiate calli. The highest average number of shoots was observed with 2 mg/l TDZ and 1 mg/l IAA. Significant differences were observed in calli producing shoots and number of shoots per callus in the explants of leaf and internode. The shoots were elongated and multiplied on MS medium supplemented with 1 mg/l BA and solidified with 1% agar. The shoots were rooted and hardened with 76% survival success in pots after six weeks of transfer to the pots.

Tissue culture and genetic analysis of somaclonal variations of Solanum melongena L. cv. Nirrala

2014 ◽  
Vol 9 (12) ◽  
pp. 1182-1195
Author(s):  
Samar Naseer ◽  
Tariq Mahmood
Keyword(s):  
Tissue Culture ◽  
Acetic Acid ◽  
Soluble Protein ◽  
Solanum Melongena ◽  
Total Soluble Protein ◽  
Naphthalene Acetic Acid ◽  
Fresh Tissue ◽  
Somaclonal Variations ◽  
Random Amplification ◽  
Plant Grown

AbstractThe present study was designed to analyze genetically somaclonal variants using biochemical and molecular markers. Efficient tissue culture protocol for Solanum melongena L. cv. Nirrala was developed. Maximum callus induction (100%) was observed for Murashige and Skoog (MS) media supplemented with 2.0 mg L−1 naphthalene acetic acid +0.5 mg L−1 6-benzylaminopurine; and nodal explants gave best callusing response (88.8%) as compared to internodes (88.3%) and leaves (87.7%). The best shooting was induced on nodal and internodal callus in the presence of 2.0 mg L−1 6-benzylaminopurine. Total soluble protein content of callus and regenerated variant plants was estimated for biochemical analysis, and largest amount of soluble protein was found in callus (6.54 mg g−1 fresh tissue) followed by variant plant grown on 2.0 mg L−1 6-benzylaminopurine (5.96 mg g−1 fresh tissue). Random amplification of polymorphic DNA technique was done with five decamer primers (OPC1-OPC5) and maximum polymorphism was detected by OPC 2 (26.99%) among all samples, whereas nodal callus on media containing 1.0 mg L−1 naphthalene acetic acid +1.0 mg L−1 6-benzylaminopurine showed highest polymorphism producing 22 bands, out of which 8 bands were polymorphic. The study shows that this marker system can provide better evaluation of genetic variation induced by tissue culture.

Multimeric connexin interactions prior to the trans-Golgi network

2001 ◽  
Vol 114 (22) ◽  
pp. 4013-4024
Author(s):  
Jayasri Das Sarma ◽  
Rita A. Meyer ◽  
Fushan Wang ◽  
Valsamma Abraham ◽  
Cecilia W. Lo ◽  
...  
Keyword(s):  
Brefeldin A ◽  
Dominant Negative ◽  
Alveolar Epithelial Cells ◽  
Trans Golgi Network ◽  
Alveolar Epithelial ◽  
C Terminus ◽  
Gradient Fractionation ◽  
Golgi Network ◽  
Nih 3T3 ◽  
Gap Junction Hemichannels

Cells that express multiple connexins have the capacity to form heteromeric (mixed) gap junction hemichannels. We used a dominant negative connexin construct, consisting of bacterial β-galactosidase fused to the C terminus of connexin43 (Cx43/β-gal), to examine connexin compatibility in NIH 3T3 cells. Cx43/β-gal is retained in a perinuclear compartment and inhibits Cx43 transport to the cell surface. The intracellular connexin pool induced by Cx43/β-gal colocalized with a medial Golgi apparatus marker and was readily disassembled by treatment with brefeldin A. This was unexpected, since previous studies indicated that Cx43 assembly into hexameric hemichannels occurs in the trans-Golgi network (TGN) and is sensitive to brefeldin A. Further analysis by sucrose gradient fractionation showed that Cx43 and Cx43/β-gal were assembled into a subhexameric complex. Cx43/β-gal also specifically interacted with Cx46, but not Cx32, consistent with the ability of Cx43/β-gal to simultaneously inhibit multiple connexins. We confirmed that interactions between Cx43/β-gal and Cx46 reflect the ability of Cx43 and Cx46 to form heteromeric complexes, using HeLa and alveolar epithelial cells, which express both connexins. In contrast, ROS osteoblastic cells, which differentially sort Cx43 and Cx46, did not form Cx43/Cx46 heteromers. Thus, cells have the capacity to regulate whether or not compatible connexins intermix.

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