Covalent linkage of [Phe2,Phe(p-N3)3]AVP to vasopressin receptors

1984 ◽  
Vol 246 (5) ◽  
pp. C486-C493 ◽  
Author(s):  
P. Eggena ◽  
F. Fahrenholz ◽  
I. L. Schwartz
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Covalent Binding ◽  
Receptor Interaction ◽  
Receptor System ◽  
Covalent Linkage ◽  
Osmotic Water ◽  
Vasopressin Receptors ◽  
History Of ◽  
Osmotic Water Flow

We have shown previously ( Eggena et al., Endocrinology 113: 1413-1421, 1983) that [Phe2,Phe(p-N3)3]-AVP induces a prolonged hydrosmotic response in the toad bladder when activated by ultraviolet (UV) light. To determine whether this response is due to covalent binding of the ligand with 8-arginine vasopressin (AVP) receptors, bladders were challenged with the ligand in the presence of AVP or the AVP antagonist, [Phe(p-N3)2]AVP, during photolysis. The permeability of bladders to water was tested subsequently in the absence of hormone or analogue. Bladders with a history of exposure to AVP (or to [Phe-(p-N3)2]AVP) during UV irradiation were considerably less permeable to water than controls, suggesting that [Phe2,Phe(p-N3)3]AVP, AVP, and [Phe(p-N3)2]AVP compete for the same receptor system during photolysis. Other experiments were directed at defining optimal conditions for covalent linkage of [Phe2,Phe(p-N3)3]AVP to receptors. These studies have indicated that two 10-min cycles of UV irradiation are more effective than one and that osmotic water flow at a rate of 1 mg X min-1 X cm-2 during irradiation does not interfere with the ligand-receptor interaction. Acidification of the serosal bath solution to pH 6.5 did not inhibit covalent binding of the ligand to receptors during photolysis. However, the capacity of the ligand-receptor complex to increase bladder permeability to water was markedly inhibited by serosal fluid acidification. These experiments have suggested that [Phe2 ,Phe(p-N3)3]AVP binds covalently to AVP receptors during photolysis and generates a signal that gradually decays as a function of time.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effect of Water Leaching on Photodegraded Scots Pine and Spruce Timbers Monitored by FTIR Spectroscopy

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 833
Author(s):  
Edina Preklet ◽  
László Tolvaj ◽  
Eszter Visi-Rajczi ◽  
Tamás Hofmann
Keyword(s):  
Ftir Spectroscopy ◽  
Scots Pine ◽  
Uv Irradiation ◽  
Chemical Elements ◽  
Uv Light ◽  
Carbonyl Groups ◽  
Water Leaching ◽  
Absorption Bands ◽  
Chemical Changes ◽  
Absorption Increase

The goal of this research was the systematic study and comparison of the divided individual effects of UV light irradiation and water leaching during artificial weathering. Spruce (Picea abies Karst.) and Scots pine (Pinus sylvestris L.) samples were irradiated by ultraviolet (UV) light. Another sequence of samples was treated with the combination of UV irradiation and water leaching. The total extent of UV treatment was 20 days for both series of samples. Time relation of UV irradiation and water leaching was 2:1. The chemical changes were observed by FTIR spectroscopy. The difference spectrum was used for determination of the chemical changes. Degradation of lignin was greater for the leached samples than for the pure UV treated samples. Scots pine suffered greater lignin degradation than spruce, and produced higher absorption increase on the absorption region of unconjugated carbonyls. The unconjugated carbonyl groups were the most responsive chemical elements to leaching. Spruce was more susceptible to leaching of unconjugated carbonyl groups than Scots pine. Two absorption bands of unconjugated carbonyl groups at 1706 and 1764 cm−1 wavenumbers were produced by photodegradation. The absorption band at 1764 cm−1 was more sensitive to water leaching than the band at 1706 cm−1.

scholarly journals UV-induced neuronal degeneration in the rat cerebral cortex

2021 ◽  
Author(s):  
Mariko Nakata ◽  
Masayuki Shimoda ◽  
Shinya Yamamoto
Keyword(s):  
Uv Irradiation ◽  
Neuronal Degeneration ◽  
Uv Light ◽  
Brain Lesion ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Heme Oxygenase 1 ◽  
Dependent Manner ◽  
Focal Brain Injury ◽  
The Brain ◽  
And Oxidative Stress

Abstract Irradiation with ultraviolet (UV) light on the cortical surface can induce a focal brain lesion (UV lesion) in rodents. In the present study, we investigated the process of establishing a UV lesion. Rats underwent UV irradiation (365 nm wavelength, 2.0 mWh) over the dura, and time-dependent changes in the cortical tissue were analyzed histologically. We found that the majority of neurons in the lesion started to degenerate within 24 hours and the rest disappeared within 5 days after irradiation. UV-induced neuronal degeneration progressed in a layer-dependent manner. Moreover, UV-induced terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positivity and heme oxygenase-1 (HO-1) immunoreactivity were also detected. These findings suggest that UV irradiation in the brain can induce gradual neural degeneration and oxidative stress. Importantly, UV vulnerability may vary among cortical layers. UV-induced cell death may be due to apoptosis; however, there remains a possibility that UV-irradiated cells were degenerated via processes other than apoptosis. The UV lesion technique will not only assist in investigating brain function at a targeted site but may also serve as a pathophysiological model of focal brain injury and/or neurodegenerative disorders.

Optimization of ultraviolet irradiation of Clarias gariepinus (Burchell, 1822) eggs for androgen production

Zygote ◽  
2021 ◽  
pp. 1-6
Author(s):  
Victor Tosin Okomoda ◽  
Haziqah Jumahat Nursyaza ◽  
Ijabo Oga Samuel ◽  
Anuar Hassan ◽  
Abraham Sunday Oladimeji ◽  
...  
Keyword(s):  
Survival Rate ◽  
Uv Irradiation ◽  
Uv Light ◽  
Clarias Gariepinus ◽  
African Catfish ◽  
Chromosome Counting ◽  
Complete Inactivation ◽  
Cell Cleavage ◽  
Optimal Protocol ◽  
Prolonged Duration

Summary The optimum distance and duration of ultraviolet (UV) irradiation for the complete inactivation of African catfish Clarias gariepinus egg nucleus was investigated in this study. The UV light was suspended above the unfertilized eggs at four distances (5, 10, 20 and 30 cm) and for five durations (1, 2, 3, 4 and 5 min). Then, the irradiated eggs were activated with sperm from diploid C. gariepinus and cold shocked at 5°C for 5 min just moments before cell cleavage. Ploidy analysis was performed using karyotype chromosome counting. The results obtained suggested that the further the distance, the better the hatchability rate, however prolonged duration seemed to significantly reduced hatchability. All treatments with surviving progenies at the end of the study showed evidence of successfully diploid gynogen (2n = 56) induction at different percentages. However, the optimal protocol that gave a moderately high hatchability/survival rate and completely induced gynogens was exposure of the eggs to UV irradiation at 20 cm for 1 min. It was concluded that the distance and duration of UV irradiation affects gynogenetic induction in African catfish C. gariepinus.

scholarly journals Mechanochemically Gated Photoswitching: Expanding the Scope of Polymer Mechanochromism

Synlett ◽  
2019 ◽  
Vol 30 (15) ◽  
pp. 1725-1732 ◽  
Author(s):  
Ross W. Barber ◽  
Molly E. McFadden ◽  
Xiaoran Hu ◽  
Maxwell J. Robb
Keyword(s):  
Mechanical Activation ◽  
Uv Light ◽  
Cycloaddition Reaction ◽  
Polymeric Materials ◽  
Diels Alder ◽  
Information Storage ◽  
Chemical Transformations ◽  
History Of ◽  
Polymer Mechanochemistry ◽  
Stress Sensing

Mechanophores are molecules that undergo productive, covalent chemical transformations in response to mechanical force. Over the last decade, a variety of mechanochromic mechanophores have been developed that enable the direct visualization of stress in polymers and polymeric materials through changes in color and chemiluminescence. The recent introduction of mechanochemically gated photoswitching extends the repertoire of polymer mechanochromism by decoupling the mechanical activation from the visible response, enabling the mechanical history of polymers to be recorded and read on-demand using light. Here, we discuss advances in mechanochromic mechanophores and present our design of a cyclopentadiene–maleimide Diels–Alder adduct that undergoes a force-induced retro-[4+2] cycloaddition reaction to reveal a latent diarylethene photoswitch. Following mechanical activation, UV light converts the colorless diarylethene molecule into the colored isomer via a 6π-electrocyclic ring-closing reaction. Mechanically gated photoswitching expands on the fruitful developments in mechanochromic polymers and provides a promising platform for further innovation in materials applications including stress sensing, patterning, and information storage.1 Introduction to Polymer Mechanochemistry2 Mechanochromic Reactions for Stress Sensing3 Regiochemical Effects on Mechanophore Activation4 Mechanochemically Gated Photoswitching5 Conclusions

scholarly journals Renin and the IGFII/M6P Receptor System in Cardiac Biology

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Jacqueline Heger ◽  
Klaus-Dieter Schlüter
Keyword(s):  
Plasma Renin ◽  
Pharmacological Intervention ◽  
Receptor Interaction ◽  
Chronic Hypertension ◽  
Receptor System ◽  
Specific Effects ◽  
Cardiac Adaptation ◽  
Pressure Independent ◽  
Independent Effects ◽  
Key Steps

Nonenzymatic cardiac activities of renin are well described during the last years and contribute either to cardiac-specific effects of the renin-angiotensin-aldosterone-system (RAAS) or to the pharmacological effects of RAAS inhibition. The interaction of renin with insulin-like growth factor II/mannose-6-phosphate (IGFII/M6P) receptors participates in nonclassical renin effects and contributes to cardiac remodelling caused by RAAS activation. The current findings suggest an important role for renin IGFII/M6P receptor interaction in cardiac adaptation to stress and support the idea that excessive accumulation of renin during inhibition of RAAS directly contributes to blood pressure-independent effects of these pharmacological interventions. It becomes a challenge for future studies focussing on chronic hypertension or myocardial infarction to comprise regulatory adaptations of the kidney, the main source of plasma renin and prorenin, because they directly contribute to key steps in regulation of cardiac (mal)adaptation via IGFII/M6P receptors. This receptor system is part of peptide/receptor interactions that modifies and possibly limits adverse remodelling effects caused by angiotensin II. Evaluation of interactions of renin with other pro-hypertrophic agonists is required to decide whether this receptor may become a target of pharmacological intervention.

Observations of TiO2 Surfaces Using Totally Reflected X-ray In-plane Diffraction Under UV Irradiation

2002 ◽  
Vol 751 ◽  
Author(s):  
T. Horiuchi ◽  
H. Ochi ◽  
K. Kaisei ◽  
K. Ishida ◽  
K. Matsushige
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Plane Surface ◽  
Signal To Noise Ratio ◽  
High Surface ◽  
Ultra Violet ◽  
High Signal ◽  
X Ray ◽  
Force Microscopy ◽  
Catalytic Activities

ABSTRACTSurface lattice displacements of titanium dioxide (TiO2: rutile) during ultra-violet (UV) light irradiation have been investigated using a total reflection x-ray diffraction, which provides a high signal to noise ratio (S/N) and superior in-plane surface diffraction. Under the environments in vapors of H2O, CH3OH, C2H5OH and C3H6OH, the photo-catalytic activities of TiO2 (110), (100) and (001) surfaces subject to UV irradiation have been measured. It is found that the diffraction peaks and their full width half maxima (FWHMs) show some peculiarities with respect to the photo-catalytic activities in both surface lattices and adsorbed molecules in vapors. Furthermore, Kelvin force microscopy (KFM) has showed that there exists a very high surface potential, probably due to surface atom displacements induced by UV irradiation. With regard to the origin of the photo-catalytic activities, the induced surface potentials are discussed.

Mechanism of bradykinin, ADH, and cAMP interaction in rabbit cortical collecting duct

1985 ◽  
Vol 249 (5) ◽  
pp. F645-F653 ◽  
Author(s):  
V. L. Schuster
Keyword(s):  
Collecting Duct ◽  
Prostaglandin Synthesis ◽  
Regulatory Subunit ◽  
Cortical Collecting Duct ◽  
Camp Generation ◽  
Osmotic Water ◽  
Transepithelial Voltage ◽  
Collecting Tubules ◽  
Prostaglandin Synthesis Inhibitors ◽  
Osmotic Water Flow

Vasopressin (ADH) and bradykinin (BK) have been shown to stimulate prostaglandin synthesis in rabbit cortical collecting tubules. We studied ADH and BK effects on osmotic water flow (Lp), Na transport (JNa), and transepithelial voltage (VT). Bath BK but not lumen BK blunted subsequent ADH hydroosmotic responses. This BK effect was prevented by ibuprofen or pertussigen pretreatment and was overcome with exogenous cAMP, suggesting that BK, via prostaglandins, interferes with ADH action on Lp at the cAMP generation step. In contrast, bath BK had no effect on bath-to-lumen (Jb-1Na) or lumen-to-bath (Jl-bNa) Na flux or on VT. As reported by others, ADH lowered Jl-bNa and depolarized VT; however, prostaglandin synthesis inhibitors neither prevented nor reversed these ADH effects. Together, these BK and ADH data do not support regulation of JNa by peptide-stimulated prostaglandins. Moreover, cAMP alone depolarized VT but had no effect on Jl-bNa. Therefore, ADH-induced depolarization of VT may at least partly owe to cAMP effects on VT independent of accompanying changes in JNa. As with Lp, bath BK blunted subsequent ADH effects on VT and, to a lesser extent, Jl-bNa; these BK effects on ADH action were also prevented by ibuprofen or pertussigen pretreatment. The data are consistent with the following model: 1) ADH depolarizes VT and increases Lp via cAMP; 2) ADH decreases JNa via neither cAMP nor prostaglandins; and 3) BK, via prostaglandins, inhibits the actions of ADH on Lp and VT at the inhibitory guanyl-nucleotide regulatory subunit of adenylate cyclase.

scholarly journals Enhanced Humidity Sensing Response of SnO2/Silicon Nanopillar Array by UV Irradiation

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2141 ◽  
Author(s):  
Wei Li ◽  
Linlin Wang ◽  
Yun Cai ◽  
Peifeng Pan ◽  
Jinze Li ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Response Time ◽  
Specific Surface ◽  
Uv Irradiation ◽  
Recovery Time ◽  
Room Temperature ◽  
Uv Light ◽  
Humidity Sensing ◽  
Potential Applications ◽  
Humidity Sensitivity

In this work, a silicon nanopillar array was created with nanosphere lithography. SnO2 film was deposited on this nanostructure by magnetron sputtering to form an SnO2/silicon nanopillar array sensor. The humidity sensitivity, response time, and recovery time were all measured at room temperature (25 °C) with UV or without UV irradiation. As a result, the humidity sensitivity properties were improved by enlarging the specific surface area with ordered nanopillars and irradiating with UV light. These results indicate that nanostructure sensors have potential applications in the field of sensors.

Transport properties of toad kidney epithelia in culture

1981 ◽  
Vol 241 (3) ◽  
pp. C154-C159 ◽  
Author(s):  
F. M. Perkins ◽  
J. S. Handler
Keyword(s):  
Electrical Resistance ◽  
Hormonal Regulation ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Transepithelial Electrical Resistance ◽  
Apical Surface ◽  
Osmotic Water ◽  
Sodium Flux ◽  
Regulation Of Transport ◽  
Osmotic Water Flow

The characteristics of a continuous line of toad kidney epithelial cells (A6) are described. These cells form a monolayer epithelium of high transepithelial electrical resistance (about 5,000 omega . cm2). The cells generate a transepithelial potential difference (apical surface negative) of about 9 mV. The short-circuit current is equivalent to net sodium flux. Net sodium flux is stimulated by aldosterone and by analogues of cAMP. The stimulation is readily reversible. Neither urea permeability nor osmotic water flow is altered by analogues of cAMP. Amiloride eliminates 90% of the short-circuit current. Thus A6 cells form an epithelium with several differentiated properties including hormonal regulation of transport.

Polyclonal antibodies in study of ADH-induced water channels in frog urinary bladder

1991 ◽  
Vol 261 (3) ◽  
pp. F437-F442
Author(s):  
G. Valenti ◽  
G. Calamita ◽  
M. Svelto
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Apical Membrane ◽  
Polyclonal Antibodies ◽  
Immune Serum ◽  
Frog Urinary Bladder ◽  
Hormonal Stimulation ◽  
Osmotic Water ◽  
Triton X ◽  
Osmotic Water Flow

It is now generally accepted that changes in water permeability in anti-diuretic hormone (ADH)-responsive target epithelial cells result from the insertion in the plasma apical membrane of new components that contain channels for water. The specificity of these channels suggests that they are formed by intrinsic proteins having access to both facies and spanning the whole membrane. We have previously shown that Triton X-100 apical extracts from ADH-stimulated frog urinary bladder contain some proteins inserted under hormonal stimulation. In the present study we have developed polyclonal antibodies using Triton X-100 extract as an immunogen. After considering the inhibitory effect exerted by the whole immune serum on the osmotic water flow, we used different adsorption steps to select, from the immune serum, antibodies to apical membrane proteins inserted in response to the hormone. Immunoblot analysis of these selected antibodies shows that they recognize seven to eight proteins, of which 55-, 35-, 26-, and 17-kDa proteins are always present. Antibodies to these four proteins, affinity purified on nitrocellulose sheets, inhibited ADH-induced osmotic water flow. Altogether these results strongly suggest that proteins of 55, 35, 26, and 17 kDa (or at least one of them) are likely to be involved in the mechanism of water transport.

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