scholarly journals Synthetic Analogue of Butenolide as an Antifouling Agent

Marine Drugs ◽  
2021 ◽  
Vol 19 (9) ◽  
pp. 481
Author(s):  
Ho Yin Chiang ◽  
Jinping Cheng ◽  
Xuan Liu ◽  
Chunfeng Ma ◽  
Pei-Yuan Qian
Keyword(s):  
Melting Point ◽  
Larval Settlement ◽  
Synthetic Analogue ◽  
Lower Toxicity ◽  
Antifouling Coatings ◽  
Antifouling Compound ◽  
Antifouling Agent ◽  
Foul Smell ◽  
High Concentrations ◽  
Coating Matrix

Butenolide derivatives have the potential to be effective and environmentally friendly antifouling agents. In the present study, a butenolide derivative was structurally modified into Boc-butenolide to increase its melting point and remove its foul smell. The structurally modified Boc-butenolide demonstrated similar antifouling capabilities to butenolide in larval settlement bioassays but with significantly lower toxicity at high concentrations. Release-rate measurements demonstrated that the antifouling compound Boc-butenolide could be released from polycaprolactone-polyurethane (PCL-PU)-based coatings to inhibit the attachment of foulers. The coating matrix was easily degraded in the marine environment. The performance of the Boc-butenolide antifouling coatings was further examined through a marine field test. The coverage of biofouler on the Boc-butenolide coatings was low after 2 months, indicating the antifouling potential of Boc-butenolide.

Evidence for Platelet αIIbβ3 Activation despite Elevated Cytosolic cAMP

2001 ◽  
Vol 85 (02) ◽  
pp. 320-325 ◽  
Author(s):  
Silvia Riondino ◽  
Fabio Pulcinelli ◽  
Pier Paolo Gazzaniga
Keyword(s):  
Platelet Aggregation ◽  
Calcium Influx ◽  
Cytosolic Calcium ◽  
Inhibitory Effect ◽  
Synthetic Analogue ◽  
Venom Toxin ◽  
Fibrinogen Binding ◽  
Snake Venom Toxin ◽  
Simultaneous Activation ◽  
High Concentrations

SummaryCyclic nucleotides, such as cAMP, are known to inhibit the multistep cascade that results in platelet aggregation. In the present study we provide evidence that it is possible to bypass cAMP inhibitory effect on fibrinogen binding site exposure induced by the thromboxane A2 synthetic analogue U46619, the snake venom toxin convulxin, or by the direct PKC activator OAG, by concomitantly activating a Gi-coupled receptor by means of epinephrine or by inducing cytosolic calcium influx by means of ionomycin. In fact, in our study we demonstrate that, in iloprost-treated platelets, the inhibition of both platelet aggregation and fibrinogen binding was overcome by adding epinephrine or ionomycin. To further confirm this, we used the cAMP analogue dibutyryl cAMP and we obtained platelet aggregation in response to U46619, convulxin or OAG plus epinephrine. Moreover, a complete inhibition of platelet aggregation in the presence of high concentrations of cAMP was observed only in the case of U46619, while a small percentage of aggregation persisted when convulxin or OAG were used, due to the small amount of ADP that both convulxin and OAG are able to release.Since PKC inhibition didn’t allow platelet aggregation to occur in response to the concomitant activation of U46619 or convulxin, plus epinephrine or ionomycin, we can conclude that cAMP-induced inhibition of aggregation can be counteracted by the simultaneous activation of PKC in the presence of an activated Gi-coupled receptor or of an induced calcium influx.

scholarly journals Imidazole and Triazole Coordination Chemistry for Antifouling Coatings

2013 ◽  
Vol 2013 ◽  
pp. 1-23 ◽  
Author(s):  
Markus Andersson Trojer ◽  
Alireza Movahedi ◽  
Hans Blanck ◽  
Magnus Nydén
Keyword(s):  
Coordination Chemistry ◽  
Controlled Release ◽  
Material Properties ◽  
Heterocyclic Compounds ◽  
Theoretical Description ◽  
Metal Coordination ◽  
Shipping Industry ◽  
Severe Problem ◽  
Antifouling Coatings ◽  
Antifouling Agent

Fouling of marine organisms on the hulls of ships is a severe problem for the shipping industry. Many antifouling agents are based on five-membered nitrogen heterocyclic compounds, in particular imidazoles and triazoles. Moreover, imidazole and triazoles are strong ligands for Cu2+and Cu+, which are both potent antifouling agents. In this review, we summarize a decade of work within our groups concerning imidazole and triazole coordination chemistry for antifouling applications with a particular focus on the very potent antifouling agentmedetomidine. The entry starts by providing a detailed theoretical description of the azole-metal coordination chemistry. Some attention will be given to ways to functionalize polymers with azole ligands. Then, the effect of metal coordination in azole-containing polymers with respect to material properties will be discussed. Our work concerning the controlled release of antifouling agents, in particular medetomidine, using azole coordination chemistry will be reviewed. Finally, an outlook will be given describing the potential for tailoring the azole ligand chemistry in polymers with respect to Cu2+adsorption and Cu2+→Cu+reduction for antifouling coatings without added biocides.

Larval settlement and metamorphosis of two gregarious sabellariid polychaetes:Sabellaria alveolatacompared withPhragmatopoma californica

1988 ◽  
Vol 68 (1) ◽  
pp. 101-124 ◽  
Author(s):  
Joseph R. Pawlik
Keyword(s):  
Larval Settlement ◽  
Larval Metamorphosis ◽  
Specific Mechanism ◽  
The West ◽  
Cemented Sand ◽  
Larval Behaviour ◽  
Naturally Occurring ◽  
Phragmatopoma Californica ◽  
Settlement And Metamorphosis ◽  
High Concentrations

Two sabellariid polychaetes,Sabellaria alveolatafrom European waters andPhragmatopoma californicafrom the west coast of North America, are known from previous work to have larvae that settle and metamorphose preferentially on the cemented sand tubes of conspecific adults. The naturally occurring inducers of larval metamorphosis were recently isolated and identified forP. californica.In the present study, larval behaviour ofS. alveolataandP. californicawas compared in reciprocal laboratory settlement assays. For both species, metamorphosis occurred to a greater extent on conspecific tube sand than on control sand or on heterospecific tube sand. Extraction of the tube sand ofS. alveolatawith organic solvents diminished its capacity to induce metamorphosis pi conspecific larvae, but this capacity was not transferred to the extracts, as was the case forP. californica. The substance responsible for the enhanced metamorphosis ofS. alveolataon conspecific tube sand remains unknown. The free fatty acid (FFA) inducers of larval metamorphosis ofP. californicaeither inhibited, or had no effect on, metamorphosis ofS. alveolata. Both species responded abnormally upon exposure to unnaturally high concentrations of certain (particularly polyenoic) FFAs. Abnormal larval responses ofS. alveolata, however, did not incorporate behavioural components of normal metamorphosis, as were observed forP. californica. FFAs were isolated from the natural tube sand ofS. alveolataat less than one-tenth the concentration found in the natural tube sand ofP. californica. The differences between the two species provide further evidence that a very specific mechanism is responsible for the perception of FFAs by the larvae ofP. californica.

scholarly journals Trehalose diester glycolipids are superior to the monoesters in binding to Mincle, activation of macrophages in vitro and adjuvant activity in vivo

2016 ◽  
Vol 22 (6) ◽  
pp. 405-418 ◽  
Author(s):  
Alexandra Huber ◽  
Rie S Kallerup ◽  
Karen S Korsholm ◽  
Henrik Franzyk ◽  
Bernd Lepenies ◽  
...  
Keyword(s):  
Macrophage Activation ◽  
Acyl Chain ◽  
No Production ◽  
Synthetic Analogue ◽  
Adjuvant Activity ◽  
Protein Insertion ◽  
Acyl Chains ◽  
High Concentrations

The T-cell adjuvanticity of mycobacterial cord factor trehalose 6,6'-dimycolate (TDM) is well established. The identification of the C-type lectin Mincle on innate immune cells as the receptor for TDM and its synthetic analogue trehalose 6,6'-dibehenate (TDB) has raised interest in development of synthetic Mincle ligands as novel adjuvants. Trehalose mono- (TMXs) and diesters (TDXs) with symmetrically shortened acyl chains [denoted by X: arachidate (A), stearate (S), palmitate (P), and myristate (M)] were tested. Upon stimulation of murine macrophages, G-CSF secretion and NO production were strongly augmented by all TDXs tested, in a wide concentration range. In contrast, the TMXs triggered macrophage activation only at high concentrations. Macrophage activation by all TDXs required Mincle, but was independent of MyD88. The superior capacity of TDXs for activating macrophages was paralleled by direct binding of TDXs, but not of TMXs, to a Mincle-Fc fusion protein. Insertion of a short polyethylene glycol between the sugar and acyl chain in TDS reduced Mincle-binding and macrophage activation. Immunization of mice with cationic liposomes containing the analogues demonstrated the superior adjuvant activity of trehalose diesters. Overall, immune activation in vitro and in vivo by trehalose esters of simple fatty acids requires two acyl chains of length and involves Mincle.

Concentration of Tributyltin in the Surface Microlayer of Natural Waters

1987 ◽  
Vol 22 (2) ◽  
pp. 227-233 ◽  
Author(s):  
R. James Maguire ◽  
Richard J. Tkacz
Keyword(s):  
New York ◽  
Natural Waters ◽  
Degradation Products ◽  
New York State ◽  
Subsurface Water ◽  
Surface Microlayer ◽  
York State ◽  
Antifouling Agent ◽  
High Concentrations ◽  
Contaminated Area

Abstract High concentrations of the very toxic antifouling agent tributyltin have been found in 24 surface microlayer samples in a survey of 74 locations in Ontario, Quebec, and New York State. In 6 of these 24 locations the concentration of tributyltin in the surface microlayer exceeded the 24-hr LC-50 value for adult rainbow trout. The most heavily contaminated area was the mouth of the Moira River at Belleville, Ontario, where the concentration of tributyltin in the surface microlayer was 42 times the 24-hr LC-50 value for trout. The concentration of tributyltin in the surface microlayer was occasionally so much greater than that in subsurface water that the microlayer contained a significant amount of tributyltin relative to that in the whole depth of the subsurface water. Similar findings were observed for the less toxic degradation products of tributyltin - dibutyltin, monobutyltin and inorganic tin.

Freeze-fracture, freeze-etch complementary pairs of virus-infected cells reveal value of etching even when relatively high concentrations of cryoprotectants are used

1978 ◽  
Vol 36 (2) ◽  
pp. 136-137
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Plant Tissue ◽  
Phosphate Buffer ◽  
Infected Plant ◽  
Freeze Fracture ◽  
Distilled Water ◽  
Virus Infected Plant ◽  
Infected Cells ◽  
High Concentrations

It has been assumed by many involved in freeze-etch or freeze-fracture studies that it would be useless to etch specimens which were cryoprotected by more than 15% glycerol. We presumed that the amount of cryoprotective material exposed at the surface would serve as a contaminating layer and prevent the visualization of fine details. Recent unexpected freeze-etch results indicated that it would be useful to compare complementary replicas in which one-half of the frozen-fractured specimen would be shadowed and replicated immediately after fracturing whereas the complement would be etched at -98°C for 1 to 10 minutes before being shadowed and replicated.Standard complementary replica holders (Steere, 1973) with hinges removed were used for this study. Specimens consisting of unfixed virus-infected plant tissue infiltrated with 0.05 M phosphate buffer or distilled water were used without cryoprotectant. Some were permitted to settle through gradients to the desired concentrations of different cryoprotectants.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

Effect of verapamil on cytoplasmic distribution of granules and microfilaments in amphibian urinary bladder

1988 ◽  
Vol 46 ◽  
pp. 324-325
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Morphological Changes ◽  
Granular Cell ◽  
Cytosolic Calcium ◽  
Calcium Storage ◽  
Amphibian Urinary Bladder ◽  
Vesicular Membrane ◽  
High Concentrations ◽  
Cytoskeletal System

The amphibian urinary bladder has been used as a ‘model’ system for studies of the mechanism of action of antidiuretic hormone (ADH) in stimulating transepithelial water flow. The increase in water permeability is accompanied by morphological changes that include the stimulation of apical microvilli, mobilization of microtubules and microfilaments and vesicular membrane fusion events . It has been shown that alterations in the cytosolic calcium concentrations can inhibit ADH transmembrane water flow and induce alterations in the epithelial cell cytomorphology, including the cytoskeletal system . Recently, the subapical granules of the granular cell in the amphibian urinary bladder have been shown to contain high concentrations of calcium, and it was suggested that these cytoplasmic constituents may act as calcium storage sites for intracellular calcium homeostasis. The present study utilizes the calcium antagonist, verapamil, to examine the effect of calcium deprivation on the cytomorphological features of epithelial cells from amphibian urinary bladder, with particular emphasis on subapical granule and microfilament distribution.

The observation of nano-voids in Au thin films

1987 ◽  
Vol 45 ◽  
pp. 366-367
Author(s):  
William Krakow
Keyword(s):  
Thin Films ◽  
Melting Point ◽  
Present Author ◽  
Stacking Faults ◽  
Damage Threshold ◽  
Ionic Species ◽  
Rare Gases ◽  
Chain Defects ◽  
Vacancy Chains ◽  
Au Thin Films

It has long been known that defects such as stacking faults and voids can be quenched from various alloyed metals heated to near their melting point. Today it is common practice to irradiate samples with various ionic species of rare gases which also form voids containing solidified phases of the same atomic species, e.g. ref. 3. Equivalently, electron irradiation has been used to produce damage events, e.g. ref. 4. Generally all of the above mentioned studies have relied on diffraction contrast to observe the defects produced down to a dimension of perhaps 10 to 20Å. Also all these studies have used ions or electrons which exceeded the damage threshold for knockon events. In the case of higher resolution studies the present author has identified vacancy and interstitial type chain defects in ion irradiated Si and was able to identify both di-interstitial and di-vacancy chains running through the foil.

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