ABSTRACT
Luminescent lanthanide chelates have been used to label antibodies in time-gated luminescence (TGL) bioimaging. However, it is a challenging task to label directly an antibody with lanthanide-binding ligands and achieve control of the target ligand/protein ratios whilst ensuring that affinity and avidity of the antibody remain uncompromised. We report the development of a new indirect detection reagent to label antibodies with detectable luminescence that circumvents this problem by labelling available lysine residues in the linker portion of the recombinant fusion protein Linker-Protein G (LPG). Succinimide-activated lanthanide chelating ligands were attached to lysine residues in LPG and Protein G (without Linker) and the resulting Luminescence-Activating (LA-) conjugates were compared for total incorporation and conjugation efficiency. A higher and more efficient incorporation of ligands at three different molar ratios was observed for LPG and this effect was attributed to the presence of eight readily available lysine residues in the linker region of LPG. These Luminescence-Activating (LA-) complexes were subsequently shown to impart luminescence (upon formation of europium(III) complexes) to cell-specific antibodies within seconds and without the need for any complicated bioconjugation procedures. The potential of this technology was demonstrated by direct labelling of Giardia cysts and Cryptosporidium oocysts in TGL bioimaging.
Subject(s)
Chelating Agents/chemistry , Lanthanoid Series Elements/chemistry , Luminescence , Recombinant Fusion Proteins/chemistry , Chelating Agents/pharmacology , Cryptosporidium/isolation & purification , Cryptosporidium/pathogenicity , Europium/chemistry , Giardia/isolation & purification , Giardia/pathogenicity , Lanthanoid Series Elements/pharmacology , Ligands , Luminescent Measurements/methods , Recombinant Fusion Proteins/pharmacologyABSTRACT
A series of proflavine derivatives for use to further image Aß amyloid deposits were synthesized and characterized. Aged 3xTg-AD (23 months old) mice hippocampus sections incubated with these derivatives revealed preferential labeling of amyloid plaques. Furthermore an in vitro binding study showed an inhibitory effect, although moderate, of these compounds on Aß(40) fibril formation. This study highlights the potential of proflavine as a molecular scaffold for designing new Aß imaging agents, its native fluorescence allowing in vitro neuropathological staining in AD damaged brain sections.
Subject(s)
Fluorescent Dyes/chemistry , Plaque, Amyloid/pathology , Proflavine/chemistry , Alzheimer Disease/pathology , Amyloid beta-Peptides/antagonists & inhibitors , Amyloid beta-Peptides/metabolism , Animals , Disease Models, Animal , Mice , Mice, Transgenic , Microscopy, Fluorescence , Peptide Fragments/antagonists & inhibitors , Peptide Fragments/metabolism , Proflavine/chemical synthesisABSTRACT
In the mol-ecule of the title compound, C(16)H(16)N(2), the ethano-strapped analogue of unsubstituted Tröger's base, the dihedral angle between the two benzene rings is 75.85â (4)°, the smallest angle measured for an ethano-strapped analogue.
ABSTRACT
In the mol-ecule of the title compound, C(16)H(14)N(2)O(2), an N,N'-dimethyl-dianthranilide, the two methyl groups are disordered over two positions; site occupation factors were kept fixed as 0.75:0.25 and 0.65:0.35. The dihedral angle between the two benzene rings is 75.57â (3)°.
ABSTRACT
The asymmetric unit of the title compound, C(21)H(22)N(2)O(4), a Tröger's base analogue derived from methyl 4-amino-phenyl-acetate, contains two crystallographically independent mol-ecules with dihedral angles of 88.44â (5) and 88.68â (6)° between the two benzene rings.
ABSTRACT
The title compound, C(15)H(10)Br(2)Cl(2)N(2), a 2,8-dibromo-4,10-dichloro Tröger's base analogue derived from 4-bromo-2-chloro-aniline, has a dihedral angle of 110.9â (10)° between the two aryl rings, the largest yet measured for a simple dibenzo analogue.
ABSTRACT
In the mol-ecule of the title compound, C(21)H(22)N(2)O(4), the 1,7-diethyl ester analogue of Tröger's base, the dihedral angle between the two benzene rings is 93.16â (3)°; the mol-ecule is C(2) symmetric.
ABSTRACT
The synthesis and redox properties of a series of free-base and metal(II) quinoxalino[2,3-b']porphyrins and their use in an investigation of the substituent effects on the degree of communication between the porphyrin and its beta,beta'-fused quinoxalino component are reported. ESR, thin-layer spectroelectrochemistry, and quantum chemical calculations of the resultant radical anions from one-electron reduction indicate that localization of the unpaired electron across both the porphyrin and the fused quinoxalino group can be controlled, the system as a whole behaving as a highly polarizable pi-expanded porphyrin radical anion. ESR studies on the radical anions of zinc(II) quinoxalino[2,3-b']porphyrin derivatives indicate that nitrogen-atom spin distribution changes as a function of chemical substitution: 27% quinoxaline character when the porphyrin ring bears a 7-nitro substituent, 34% quinoxaline character in the unsubstituted parent, and 51-61% nitroquinoxaline character when the quinoxalino unit has one or more nitro groups. Close analogies are found between the calculated and observed nitrogen-atom spin distributions, indicating that the calculations embody the key chemical effects. The calculations also indicate that the nitrogen-atom spin distributions closely parallel the important total porphyrin, quinoxaline, and nitro spin distributions, indicating that the observed quantities realistically depict the change in the nature of the delocalization of the radical anion as a function of chemical substitution. The profound effects observed indicate long-range communication of the type that is essential in molecular electronics applications.
ABSTRACT
In the mol-ecule of the title compound, C(16)H(14)Cl(2)N(2), the ethano-strapped 2,8-dichloro analogue of Tröger's base, the dihedral angle between the two benzene rings is 87.01â (3)°.
ABSTRACT
This study undertook an empirically based examination of the cognitive processes associated with the accurate construction of a criminal psychological profile. This was accomplished by comparing the abilities of profilers and nonprofilers in two simulated profiling exercises that measured both profile accuracy and an individual's performance on various tests of memory and comprehension related to the case materials presented in each exercise. The results of these experiments suggest that an incremental relationship exists between comprehension of the case materials and accuracy of the profiles generated. In addition, the findings provide some tentative indications that the comprehension of case material in a narrative (i.e., written) format is an integral cognitive function to proficient profiling.
