Photoresponsive molecular tweezer: Control-release of anions and fluorescence switch

SummaryIn endothelial cells von Willebrand factor (vWF) and P-selectin are stored in dense granules, so-called Weibel-Palade bodies. Upon stimulation of endothelial cells with a variety of agents including thrombin, these organelles fuse with the plasma membrane and release their content. Small GTP-binding proteins have been shown to control release from intracellular storage pools in a number of cells. In this study we have investigated whether small GTP-binding proteins are associated with Weibel-Palade bodies. We isolated Weibel-Palade bodies by centrifugation on two consecutive density gradients of Percoll. The dense fraction in which these subcellular organelles were highly enriched, was analysed by SDS-PAGE followed by GTP overlay. A distinct band with an apparent molecular weight of 28,000 was observed. Two-dimensional gel electrophoresis followed by GTP overlay revealed the presence of a single small GTP-binding protein with an isoelectric point of 7.1. A monoclonal antibody directed against RalA showed reactivity with the small GTP-binding protein present in subcellular fractions that contain Weibel-Palade bodies. The small GTPase RalA was previously identified on dense granules of platelets and on synaptic vesicles in nerve terminals. Our observations suggest that RalA serves a role in regulated exocytosis of Weibel-Palade bodies in endothelial cells.

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Hybrid nanoparticle based fluorescence switch for recognition of ketoprofen in aqueous media

Molecular Systems Design & Engineering ◽

10.1039/d0me00065e ◽

2020 ◽

Vol 5 (8) ◽

pp. 1428-1436

Author(s):

Anu Saini ◽

Manpreet Kaur ◽

Mayank ◽

Anil Kuwar ◽

Navneet Kaur ◽

...

Keyword(s):

Aqueous Media ◽

Fluorescent Chemosensors ◽

Fluorescence Switch ◽

Nanomolar Detection ◽

Hybrid Nanoparticle

Hybrid nanoassembly, fluorescent chemosensors, selective response to ketoprofen, and nanomolar detection.

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The synthesis and characterization of layered hydroxide salt interleaved with 4-chlorophenoxyacetic acid and its control release study as herbicide

10.1063/5.0043290 ◽

2021 ◽

Author(s):

Farah Liyana Bohari ◽

Fardzil Idham Sufian ◽

Sheikh Ahmad Izaddin Sheikh Mohd Ghazali ◽

Nur Nadia Dzulkifli

Keyword(s):

Control Release ◽

Synthesis And Characterization ◽

Chlorophenoxyacetic Acid ◽

Release Study

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Binding Properties of a Dinuclear Zinc(II) Salen-Type Molecular Tweezer with a Flexible Spacer in the Formation of Lewis Acid-Base Adducts with Diamines

Inorganics ◽

10.3390/inorganics9060049 ◽

2021 ◽

Vol 9 (6) ◽

pp. 49

Author(s):

Gabriella Munzi ◽

Giuseppe Consiglio ◽

Salvatore Failla ◽

Santo Di Bella

Keyword(s):

Lewis Acid ◽

Degrees Of Freedom ◽

Binding Constants ◽

Molecular Structures ◽

Acid Base ◽

Binding Properties ◽

Binding Characteristics ◽

Fluorescence Studies ◽

Flexible Spacer ◽

Molecular Tweezer

In this paper we report the binding properties, by combined 1H NMR, optical absorption, and fluorescence studies, of a molecular tweezer composed of two Zn(salen)-type Schiff-base units connected by a flexible spacer, towards a series of ditopic diamines having a strong Lewis basicity, with different chain length and rigidity. Except for the 1,2-diaminoethane, in all other cases the formation of stable 1:1 Lewis acid-base adducts with large binding constants is demonstrated. For α,ω-aliphatic diamines, binding constants progressively increase with the increasing length of the alkyl chain, thanks to the flexible nature of the spacer and the parallel decreased conformational strain upon binding. Stable adducts are also found even for short diamines with rigid molecular structures. Given their preorganized structure, these latter species are not subjected to loss of degrees of freedom. The binding characteristics of the tweezer have been exploited for the colorimetric and fluorometric selective and sensitive detection of piperazine.

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