The role of endothelium in the vasorelaxant effects of the essential oil of Ocimum gratissimum in aorta and mesenteric vascular bed of rats

This study investigated the endothelium-dependent vasorelaxant effects of the essential oil of Ocimum gratissimum (EOOG) in aortas and mesenteric vascular beds isolated from rats. EOOG (3–300 µg/mL) relaxed the tonic contractions induced by phenylephrine (0.1 µmol/L) in isolated aortas in a concentration-dependent manner in both endothelium-containing and endothelium-denuded preparations. This effect was partially reversed by L-NAME (100 µmol/L) but not by indomethacin (10 µmol/L) or TEA (5 mmol/L). In mesenteric vascular beds, bolus injections of EOOG (30, 50, 100, and 300 ng) decreased the perfusion pressure induced by noradrenaline (6 µmol/L) in endothelium-intact preparations but not in those treated with deoxycholate. L-NAME (300 µmol/L) but not TEA (1 mmol/L) or indomethacin (3 µmol/L) significantly reduced the vasodilatory response to EOOG at all of the doses tested. Our data showed that EOOG exerts a dose-dependent vasodilatory response in the resistance blood vessels of rat mesenteric vascular beds and in the capacitance blood vessel, the rat aorta. This action is completely dependent on endothelial nitric oxide (NO) release in the mesenteric vascular beds but only partially dependent on NO in the aorta. These novel effects of EOOG highlight interesting differences between resistance and capacitance blood vessels.

Download Full-text

The P-element-induced silencing effect of KP transposons is dose dependent in Drosophila melanogaster

Genome ◽

10.1139/g11-023 ◽

2011 ◽

Vol 54 (9) ◽

pp. 752-762 ◽

Cited By ~ 7

Author(s):

Alireza Sameny ◽

John Locke

Keyword(s):

Drosophila Melanogaster ◽

Critical Role ◽

Mutagenic Effect ◽

P Element ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

P Elements ◽

Single Well ◽

Dose Dependent

Transposable elements are found in the genomes of all eukaryotes and play a critical role in altering gene expression and genome organization. In Drosophila melanogaster, transposable P elements are responsible for the phenomenon of hybrid dysgenesis. KP elements, a deletion-derivative of the complete P element, can suppress this mutagenic effect. KP elements can also silence the expression of certain other P-element-mediated transgenes in a process called P-element-dependent silencing (PDS), which is thought to involve the recruitment of heterochromatin proteins. To explore the mechanism of this silencing, we have mobilized KP elements to create a series of strains that contain single, well-defined KP insertions that show PDS. To understand the quantitative role of KP elements in PDS, these single inserts were combined in a series of crosses to obtain genotypes with zero, one, or two KP elements, from which we could examine the effect of KP gene dose. The extent of PDS in these genotypes was shown to be dose dependent in a logarithmic rather than linear fashion. A logarithmic dose dependency is consistent with the KP products interacting with heterochromatic proteins in a concentration-dependent manner such that two molecules are needed to induce gene silencing.

Download Full-text

Protein kinase C potentiates cAMP-stimulated mouse duodenal mucosal bicarbonate secretion in vitro

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00251.2003 ◽

2004 ◽

Vol 286 (5) ◽

pp. G814-G821 ◽

Cited By ~ 10

Author(s):

Bi-Guang Tuo ◽

Jimmy Y. C. Chow ◽

Kim E. Barrett ◽

Jon I. Isenberg

Keyword(s):

Short Circuit ◽

Short Circuit Current ◽

Duodenal Mucosa ◽

Bicarbonate Secretion ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Ussing Chambers ◽

Duodenal Bicarbonate Secretion

PKC has been shown to regulate epithelial Cl- secretion in a variety of models. However, the role of PKC in duodenal mucosal bicarbonate secretion is less clear. We aimed to investigate the role of PKC in regulation of duodenal mucosal bicarbonate secretion. Bicarbonate secretion by murine duodenal mucosa was examined in vitro in Ussing chambers using a pH-stat technique. PKC isoform expression and activity were assessed by Western blotting and in vitro kinase assays, respectively. PMA (an activator of PKC) alone had no effect on duodenal bicarbonate secretion or short-circuit current ( Isc). When PMA and dibutyryl-cAMP (db-cAMP) were added simultaneously, PMA failed to alter db-cAMP-stimulated duodenal bicarbonate secretion or Isc ( P > 0.05). However, a 1-h preincubation with PMA potentiated db-cAMP-stimulated duodenal bicarbonate secretion and Isc in a concentration-dependent manner (from 10-8 to 10-5M) ( P < 0.05). PMA preincubation had no effects on carbachol- or heat-stable toxin-stimulated bicarbonate secretion. Western blot analysis revealed that PKCα, -γ, -ϵ, -θ, -μ, and -ι/λ were expressed in murine duodenal mucosa. Ro 31–8220 (an inhibitor active against PKCϵ, -α, -β, and -γ), but not Gö 6983 (an inhibitor active against PKCα, -γ, -β, and -δ), reversed the potentiating effect of PMA on db-cAMP-stimulated bicarbonate secretion. PMA also time- and concentration-dependently increased the activity of PKCϵ, an effect that was prevented by Ro 31–8220 but not Gö 6983. These results demonstrate that activation of PKC potentiates cAMP-stimulated duodenal bicarbonate secretion, whereas it does not modify basal secretion. The effect of PKC on cAMP-stimulated bicarbonate secretion is mediated by the PKCϵ isoform.

Download Full-text

Sec1p directly stimulates SNARE-mediated membrane fusion in vitro

The Journal of Cell Biology ◽

10.1083/jcb.200405018 ◽

2004 ◽

Vol 167 (1) ◽

pp. 75-85 ◽

Cited By ~ 79

Author(s):

Brenton L. Scott ◽

Jeffrey S. Van Komen ◽

Hassan Irshad ◽

Song Liu ◽

Kirilee A. Wilson ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Membrane Fusion ◽

Membrane Trafficking ◽

Snare Complex ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Bud Neck ◽

Precise Role

Sec1 proteins are critical players in membrane trafficking, yet their precise role remains unknown. We have examined the role of Sec1p in the regulation of post-Golgi secretion in Saccharomyces cerevisiae. Indirect immunofluorescence shows that endogenous Sec1p is found primarily at the bud neck in newly budded cells and in patches broadly distributed within the plasma membrane in unbudded cells. Recombinant Sec1p binds strongly to the t-SNARE complex (Sso1p/Sec9c) as well as to the fully assembled ternary SNARE complex (Sso1p/Sec9c;Snc2p), but also binds weakly to free Sso1p. We used recombinant Sec1p to test Sec1p function using a well-characterized SNARE-mediated membrane fusion assay. The addition of Sec1p to a traditional in vitro fusion assay moderately stimulates fusion; however, when Sec1p is allowed to bind to SNAREs before reconstitution, significantly more Sec1p binding is detected and fusion is stimulated in a concentration-dependent manner. These data strongly argue that Sec1p directly stimulates SNARE-mediated membrane fusion.

Download Full-text

Aristoteline, an Indole-Alkaloid, Induces Relaxation by Activating Potassium Channels and Blocking Calcium Channels in Isolated Rat Aorta

Molecules ◽

10.3390/molecules24152748 ◽

2019 ◽

Vol 24 (15) ◽

pp. 2748 ◽

Cited By ~ 1

Author(s):

Fernando Romero ◽

Javier Palacios ◽

Ignacio Jofré ◽

Cristian Paz ◽

Chukwuemeka R. Nwokocha ◽

...

Keyword(s):

Potassium Channels ◽

Vascular Reactivity ◽

Soluble Guanylate Cyclase ◽

Indole Alkaloid ◽

Soluble Guanylyl Cyclase ◽

Rat Aorta ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Cav1.2 Channels ◽

Aristotelia Chilensis

Alkaloids derived from plants have shown great medicinal benefits, and are often reported for their use in cardiovascular disease management. Aristotelia chilensis (Molina) Stuntz (Maqui) has shown important medicinal properties in traditional useage. In this study, we evaluated the effect of the indole-alkaloid aristoteline (ARI), isolated from leaves of Maqui, on vascular reactivity of isolated aortic rings from normotensive rats. ARI induced relaxation (100%) in a concentration-dependent manner in intact or denuded-endothelium aortic rings pre-contracted with phenylephrine (PE; 1 μM). However, a specific soluble guanylyl cyclase inhibitor (ODQ; 1 μM) significantly reduced the relaxation to ARI in aortic rings pre-contracted with PE. In the presence of ARI, the contraction induced by KCl or PE was significantly (p < 0.05) decreased. Interestingly, the potassium channel blockade with 10 μM BaCl2 (Kir), 10 μM glibenclamide (KATP), 1 mM tetraethylammonium (TEA; KCa1.1), or 1 mM 4-aminopyridine (4-AP; Kv) significantly (p < 0.05) reduced the ARI-induced relaxation. ARI significantly (p < 0.05) reduced the contractile response to agonist of CaV1.2 channels (Bay K8644; 10 nM), likely reducing the influx of extracellular calcium through plasma membrane. The mechanisms associated with this process suggest an activation of the potassium channels, a calcium-induced antagonism and endothelium independent vasodilation that possibly involves the nitric oxide-independent soluble guanylate cyclase pathway.

Download Full-text

Phytotoxic potential of essential oil of Melaleuca leucadendra against some agricultural weeds

Annals of Plant Sciences ◽

10.21746/aps.2017.6.11.14 ◽

2017 ◽

Vol 6 (11) ◽

pp. 1799

Author(s):

Gunjan Goyal

Keyword(s):

Essential Oil ◽

Chlorophyll Content ◽

Volatile Oil ◽

Cyperus Rotundus ◽

Maximum Effect ◽

Dependent Manner ◽

Weed Species ◽

Concentration Dependent Manner ◽

Root And Shoot Length ◽

Melaleuca Leucadendra

The work was undertaken to investigate the phytotoxic potential of essential oil from Melaleuca leucadendra against three weed species, viz., Echinochloa crus-galli, Cyperus rotundus and Leptochloa chinensis. It was observed that volatile oil (0.25-1.5 mg ml-1) of Melaleuca retarded the germination and growth of all the test weeds in a dose-response bioassay conducted under laboratory conditions. Generally, both root and shoot length showed an inhibitory effect in a concentration dependent manner and the maximum effect was observed in C. rotundus, followed by E. crus-galli and L. chinensis. The Melaleuca oil not only affected the germination and seedling growth of the test weeds, but also inhibited the chlorophyll content and dry weight. At the highest dose of Melaleuca oil treatment (1.5 mg ml-1), the chlorophyll content declined by nearly 50% in E. crus-galli and 90% in L. chinensis over the control. Thus, it is concluded that volatile oil possesses phytotoxic potential towards other plants and could be further explored for weed management.

Download Full-text

Effect of Palmitic Acid on Exosome-Mediated Secretion and Invasive Motility in Prostate Cancer Cells

Molecules ◽

10.3390/molecules25122722 ◽

2020 ◽

Vol 25 (12) ◽

pp. 2722

Author(s):

Ivan V. Maly ◽

Wilma A. Hofmann

Keyword(s):

Prostate Cancer ◽

Palmitic Acid ◽

Cancer Cells ◽

Dependent Manner ◽

Prostate Cancer Cells ◽

Concentration Dependent Manner ◽

Fat Consumption ◽

Progression Markers

High fat consumption can enhance metastasis and decrease survival in prostate cancer, but the picture remains incomplete on the epidemiological and cell-biological level, impeding progress toward individualized recommendations in the clinic. Recent work has highlighted the role of exosomes secreted by prostate cancer cells in the progression of the disease, particularly in metastatic invasion, and also the utility of targeting these extracellular vesicles for diagnostics, as carriers of disease progression markers. Here, we investigated the question of a potential impact of the chief nutritional saturated fatty acid on the exosome secretion. Palmitic acid decreased the secretion of exosomes in human prostate cancer cells in vitro in a concentration-dependent manner. At the same time, the content of some prospective metastatic markers in the secreted exosomal fraction was also reduced, as was the ability of the cells to invade across extracellular matrix barriers. While by themselves our in vitro results imply that on the cell level, palmitic acid may be beneficial vis-à-vis the course of the disease, they also suggest that, by virtue of the decreased biomarker secretion, palmitic acid has the potential to cause unjustified deprioritization of treatment in obese and lipidemic men.

Download Full-text

The Role Of Calcium In Platelet Microtubule Assembly- Disassembly

10.1055/s-0038-1652479 ◽

1981 ◽

Author(s):

M Kikuchi ◽

Y Ikeda ◽

M Handa ◽

S Matsuda ◽

H Muraki ◽

...

Keyword(s):

Intracellular Calcium ◽

Dynamic Equilibrium ◽

Platelet Rich Plasma ◽

Human Platelets ◽

Microtubule Assembly ◽

Base Line ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Transient Decrease

Microtubules exist in a dynamic equilibrium between polymerized and depolymerized forms in human platelets, playing a major role to maintain the discoid shape of platelets. It has been previously shown that the interaction of aggregating agents with platelets leads to a rapid but transient disassembly of microtubules. ( Steiner and Ikeda, J.Clin. Invest. 63:443,1979 ) In this paper, the role of calcium in the equilibrium between assembled and disassembled microtubules was investigated. The respective pools of soluble and polymerized tubulin were “frozen” by addition of a glycerol-dimethyl sulfoxide-containing medium to platelet rich plasma, preincubated with 2 µM A23187 for various time intervals. The two pools of tubulin were estimated by measuring the colchicine binding activities of total and polymerized tubulin according to the method of Wilson.Resting platelets were found to contain 56.2 ± 2.7 µg tubulin per 109 platelets, of which 56.7 % was in polymerized form. Addition of A23187 to platelet rich plasma produced a transient decrease in the pool of polymerized tubulin within 30 sec., followed by a return to base-line values within 2 min.. TMB-8, a known intracellular calcium antagonist, abolished this transient decrease in polymerized tubulin induced by A23187 in a concentration dependent manner, while indomethacin or acetylsalycylic acid did not.These findings may indicate the important role of intracellular calcium in microtubule assembly-disassembly.

Download Full-text

Assessment of Chitosan-Rue (Ruta graveolens L.) Essential Oil-Based Coatings on Refrigerated Cape Gooseberry (Physalis peruviana L.) Quality

Applied Sciences ◽

10.3390/app10082684 ◽

2020 ◽

Vol 10 (8) ◽

pp. 2684

Author(s):

María González-Locarno ◽

Yarley Maza Pautt ◽

Alberto Albis ◽

Edwin Florez López ◽

Carlos David Grande Tovar

Keyword(s):

Essential Oil ◽

Antioxidant Capacity ◽

Lower Amount ◽

Edible Coatings ◽

Dependent Manner ◽

Ruta Graveolens ◽

Concentration Dependent Manner ◽

Physalis Peruviana ◽

Dpph Method ◽

Cape Gooseberry

Cape gooseberry (Physalis peruviana L.) is one of the main exotic fruits in demand throughout the world market. However, this fruit has problems with physical and microbial decay causing losses up to thirty percent during post-harvest stage and market storage. As an alternative for conservation, technologies based on edible coatings of biopolymers incorporating essential oils have been developed. In this paper we studied the effect of edible coatings based on chitosan (CS) and Ruta graveolens L. essential oil (RGEO) at different concentrations applied on the surface gooseberries at 18 ± 2 °C. The emulsions exhibited a reduction in the viscosity and the particle size with the increasing in the RGEO amount (from 124.7 cP to 26.0 cP for CS + RGEO 0.5% and CS + RGEO 1.5%, respectively). A lower weight loss was obtained for fruits coated with CS + RGEO 0.5% (12.7%) as compared to the uncoated (15%), while the maturity index increased in a lower amount for CS + RGEO coated than the uncoated fruits. The mesophyll growth was delayed three days after the coating applications for CS + RGEO 1.0% and 1.5%. At day twelve of the coating process, fruits with CS + RGEO 1.5% presented only 3.1 Log UFC/g of aerobic mesophylls and 2.9 Log UFC/g of molds and yeasts, while the uncoated fruits presented 4.2 Log UFC/g of aerobic mesophylls and 4.0 Log UFC/g of molds and yeasts, demonstrating a microbial barrier of the coatings incorporating RGEO in a concentration dependent manner. The CS + RGEO coating also preserve the antioxidant property of case gooseberries after twelve days of treatment under storage according to the 2,2′-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethyl-benzothiazoline-6-sulphonic acid) (ABTS) results. It was demonstrated by the ABTS method that T5 antioxidant capacity from day one to day twelve only decreases from 55% to 44%, while in the uncoated fruits (T1) the antioxidant capacity decreased from 65% to 18%. On the other hand, using the DPPH method the reduction was from 73% to 24% for the uncoated samples and 55% to 43% for T5. From the sensorial analysis, we recommend the use of CS + RGEO 0.5% that was still accepted by the panelists after the sixth day of application. These results show the potential application of these coatings as postharvest treatment under storage and low temperature conditions during twelve days of treatment for cape gooseberry fruits.

Download Full-text

Antiarrhythmic Properties of Elsholtzia ciliata Essential Oil on Electrical Activity of the Isolated Rabbit Heart and Preferential Inhibition of Sodium Conductance

Biomolecules ◽

10.3390/biom10060948 ◽

2020 ◽

Vol 10 (6) ◽

pp. 948

Author(s):

Regina Mačianskienė ◽

Lauryna Pudžiuvelytė ◽

Jurga Bernatonienė ◽

Mantė Almanaitytė ◽

Antanas Navalinskas ◽

...

Keyword(s):

Essential Oil ◽

Electrical Activity ◽

Rabbit Heart ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Cardiac Electrical Activity ◽

Surface Ecg ◽

Elsholtzia Ciliata ◽

Qrs Duration ◽

Mapping Techniques

Elsholtzia ciliata essential oil (E. ciliata) has been developed in Lithuania and internationally patented as exerting antiarrhythmic properties. Here we demonstrate the pharmacological effects of this herbal preparation on cardiac electrical activity. We used cardiac surface ECG and a combination of microelectrode and optical mapping techniques to track the action potentials (APs) in the Langendorff-perfused rabbit heart model during atrial/endo-/epi-cardial pacing. Activation time, conduction velocity and AP duration (APD) maps were constructed. E. ciliata increased the QRS duration and shortened QT interval of ECG at concentrations of 0.01–0.1 μL/mL, whereas 0.3 μL/mL (0.03%) concentration resulted in marked strengthening of changes. In addition, the E. ciliata in a concentration dependent manner reduced the AP upstroke dV/dtmax and AP amplitude as well as APD. A marked attenuation of the AP dV/dtmax and a slowing spread of electrical signals suggest the impaired functioning of Na+-channels, and the effect was use-dependent. Importantly, all these changes were at least partially reversible. Our results indicate that E. ciliata modulates cardiac electrical activity preferentially inhibiting Na+ conductance, which may contribute to its effects as a natural antiarrhythmic medicine.

Download Full-text

Potentiation of angiotensin II-stimulated vascular contraction by lithium

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1995.268.5.h2009 ◽

1995 ◽

Vol 268 (5) ◽

pp. H2009-H2016

Author(s):

M. E. Ullian ◽

L. G. Walsh ◽

K. C. Wong ◽

C. J. Allan

Keyword(s):

Angiotensin Ii ◽

Inositol Phosphate ◽

Cytosolic Calcium ◽

Rat Aorta ◽

Dependent Manner ◽

Ang Ii ◽

Concentration Dependent Manner ◽

Adrenergic Agents ◽

Phosphoinositide Signaling ◽

Protein Kinase C Inhibitor

Previous studies have suggested that lithium prolongs or enhances vascular contractions stimulated by alpha-adrenergic agents. The present study was performed to determine whether a similar phenomenon occurs with angiotensin II (ANG II)-stimulated contractions and whether this phenomenon results from interactions with the phosphoinositide signaling system. Contractions of rat aortic rings with 100 nM ANG II were 38% greater in the presence of 20 mM LiCl than in its absence (0.47 +/- 0.07 vs. 0.34 +/- 0.05 g tension/mg dry tissue wt, P < 0.01). The effects of lithium on inositol phosphate responses, diacylglycerol responses, and intracellular calcium concentration on single or repeated stimulations with ANG II were then examined in vascular smooth muscle cells cultured from rat aorta. Cells exposed twice to 100 nM ANG II contained 50% lower inositol trisphosphate levels (InsP3) and 10% lower diacylglycerol levels than cells exposed to ANG II only once. LiCl or lithium acetate abolished these desensitizations in a concentration-dependent manner. Similarly, InsP3 and diacylglycerol responses to a single exposure of ANG II were heightened by lithium (by 75 and 25%, respectively), and the duration of the responses was prolonged by lithium (5- and 2-fold, respectively). In contrast, ANG II-stimulated calcium transients were not enhanced or prolonged by lithium, nor was desensitization of ANG II-stimulated cytosolic calcium mobilization upon serial exposures abolished by lithium. When ring contraction studies were repeated in the presence of the protein kinase C inhibitor staurosporine (150 nM), lithium no longer potentiated ANG II contractions [0.38 +/- 0.03 (control) vs. 0.35 +/- 0.06 g tension/mg dry tissue wt (lithium)].(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text