scholarly journals Characterization of New Formalin-Detoxified Botulinum Neurotoxin Toxoids

2008 ◽  
Vol 15 (9) ◽  
pp. 1374-1379 ◽  
Author(s):  
James E. Keller
Keyword(s):  
Botulinum Neurotoxin ◽  
Lethal Dose ◽  
Enzyme Linked Immunosorbent Assay ◽  
Reaction Conditions ◽  
Inhibition Elisa ◽  
Naturally Occurring ◽  
Antibody Titers

ABSTRACT Antigenicities of several formalin-detoxified botulinum neurotoxin preparations were measured by inhibition and sandwich enzyme-linked immunosorbent assay (ELISA), and immunogenicity was studied in mice. The toxoids were derived primarily from the serotype A 150-kDa neurotoxin protein, while one toxoid was derived from the naturally occurring 900-kDa toxin-hemagglutinin complex. Antigenicity was severely compromised in two commercially available toxoids. A variety of new toxoids were synthesized in-house by optimizing formaldehyde reaction conditions. Three of the resulting toxoids were found to be antigenically identical to the native toxin, as measured by inhibition ELISA, in spite of showing a reduction of toxicity by more than 100,000-fold. Sandwich ELISAs indicated that the in-house toxoids were two- to threefold less antigenic than the neurotoxin compared to commercial toxoids, which were about 100-fold less antigenic. Mice were immunized twice, on day 0 and day 14. By day 28, relatively high toxin-specific immunoglobulin G (IgG) titers were detected in animals that had received any of the in-house toxoids, with greater than 99% being IgG1 and the remainder being IgG2. These immunized mice remained asymptomatic after being challenged with 50 to 1,000,000 50% lethal dose (LD50) units of the 900-kDa neurotoxin. In contrast, animals immunized with several different batches of commercially available toxoids did not develop measurable toxin-specific antibody titers. However, these mice survived neurotoxin challenges with 2 LD50 units but died when challenged with 6 LD50 units. Neutralizing titers measured from pools of sera generated with the in-house toxoid preparations ranged from 2.5 to 5 U/ml. In terms of predicting immunogenicity, inhibition ELISAs comparing each formalin toxoid to the parent toxin provided good insight for screening the new toxoids as well as for estimating their relative in vivo potencies. Inhibition ELISA data indicate that those toxoids that most closely resemble the native toxin are highly immunogenic and protective. The superior quality of these new toxoids makes them useful tools for continued use in ELISA development and for antitoxin production.

scholarly journals A Minimal Metric for the Characterization of Acoustic Noise Emitted by Underwater Vehicles

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6644
Author(s):  
Giacomo Picardi ◽  
Clara Borrelli ◽  
Augusto Sarti ◽  
Giovanni Chimienti ◽  
Marcello Calisti
Keyword(s):  
Acoustic Noise ◽  
Acoustic Emissions ◽  
Remotely Operated Vehicles ◽  
Underwater Robots ◽  
Acoustic Disturbance ◽  
Marine Fauna ◽  
Acoustic Data

Underwater robots emit sound during operations which can deteriorate the quality of acoustic data recorded by on-board sensors or disturb marine fauna during in vivo observations. Notwithstanding this, there have only been a few attempts at characterizing the acoustic emissions of underwater robots in the literature, and the datasheets of commercially available devices do not report information on this topic. This work has a twofold goal. First, we identified a setup consisting of a camera directly mounted on the robot structure to acquire the acoustic data and two indicators (i.e., spectral roll-off point and noise introduced to the environment) to provide a simple and intuitive characterization of the acoustic emissions of underwater robots carrying out specific maneuvers in specific environments. Second, we performed the proposed analysis on three underwater robots belonging to the classes of remotely operated vehicles and underwater legged robots. Our results showed how the legged device produced a clearly different signature compared to remotely operated vehicles which can be an advantage in operations that require low acoustic disturbance. Finally, we argue that the proposed indicators, obtained through a standardized procedure, may be a useful addition to datasheets of existing underwater robots.

Production and Characterization of Antibodies against Fumonisin B1

1996 ◽  
Vol 59 (9) ◽  
pp. 992-997 ◽  
Author(s):  
FENG-YIR YU ◽  
FUN S. CHU
Keyword(s):  
Detection Limit ◽  
Polyclonal Antibodies ◽  
Fumonisin B1 ◽  
Correlation Coefficients ◽  
Keyhole Limpet Hemocyanin ◽  
Hplc Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Indirect Competitive Elisa ◽  
Antibody Titers

Polyclonal antibodies against fumonisin B1 (FmB1) were produced in rabbits after immunizing the animals with either FmBl-keyhole limpet hemocyanin (KLH) or FmB1 bovine serum albumin (BSA). A direct competitive enzyme-linked immunosorbent assay (dc-ELISA) and an indirect competitive ELISA (idc-ELISA) were used for the characterization of the antibodies and for analysis of the toxin in corn samples. The antibody titers in the serum of rabbits immunized with FmBl-KLH were considerably higher than in those immunized with FmBl-BSA. The antibodies from the rabbits immunized with FmBl-KLH were further characterized. The concentrations causing 50% inhibition of binding of FmB1-horseradish peroxidase (HRP) to the antibodies by FmB1, FmB2 and FmB3 in the ELISA were found to be 0.45, 0.72, and 25 ng/ml, respectively. The detection limit of FmBl, based on 95% confidence at 5% of inhibition of binding of FmBl-HRP conjugate, in buffer of the dc-ELISA was found to be 0.05 ng/ml. In the presence of a matrix such as corn, the detection limit was less than 50 ppb. The overall analytical recoveries of FmBl (50 to 1,000 ng/g) added to the ground corn and then extracted with CH3CN/H2O (1/1, vol/vol) with cleanup and without cleanup in the dc ELISA were found to be 70.5 and 85.9%, respectively. A good correlation was found between the FmBl levels in 2 starch and 10 naturally contaminated corn samples analyzed by the dc-ELISA and the high-pressure liquid chromatography (HPLC) method. The correlation coefficients between ELISA and HPLC were found to be 0.955 (y [ELISA] = 1.3 1x [HPLC] + 77 ppb; P < 0.001) and 0.811 (y = 1.13x + 34 ppb; P < 0.01) for the sample without and with cleanup treatment, respectively.

scholarly journals Fluid Structural Analysis of Urine Flow in a Stented Ureter

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
J. Carlos Gómez-Blanco ◽  
F. Javier Martínez-Reina ◽  
Domingo Cruz ◽  
J. Blas Pagador ◽  
Francisco M. Sánchez-Margallo ◽  
...  
Keyword(s):  
Computational Models ◽  
Mechanical Characterization ◽  
Ex Vivo ◽  
Biological Tissues ◽  
Urine Flow ◽  
Computational Environment ◽  
Computational Fluid Dynamics Cfd

Many urologists are currently studying new designs of ureteral stents to improve the quality of their operations and the subsequent recovery of the patient. In order to help during this design process, many computational models have been developed to simulate the behaviour of different biological tissues and provide a realistic computational environment to evaluate the stents. However, due to the high complexity of the involved tissues, they usually introduce simplifications to make these models less computationally demanding. In this study, the interaction between urine flow and a double-J stented ureter with a simplified geometry has been analysed. The Fluid-Structure Interaction (FSI) of urine and the ureteral wall was studied using three models for the solid domain: Mooney-Rivlin, Yeoh, and Ogden. The ureter was assumed to be quasi-incompressible and isotropic. Data obtained in previous studies from ex vivo and in vivo mechanical characterization of different ureters were used to fit the mentioned models. The results show that the interaction between the stented ureter and urine is negligible. Therefore, we can conclude that this type of models does not need to include the FSI and could be solved quite accurately assuming that the ureter is a rigid body and, thus, using the more simple Computational Fluid Dynamics (CFD) approach.

In Vivo Toxicity and Immunological Characterization of Detoxified Recombinant Botulinum Neurotoxin Type A

2015 ◽  
Vol 33 (3) ◽  
pp. 639-652 ◽  
Author(s):  
Easwaran Ravichandran ◽  
Pavithra Janardhanan ◽  
Kruti Patel ◽  
Stephen Riding ◽  
Shuowei Cai ◽  
...  
Keyword(s):  
Botulinum Neurotoxin ◽  
Type A ◽  
Immunological Characterization ◽  
In Vivo Toxicity ◽  
Botulinum Neurotoxin Type A

scholarly journals Preclinical characterization of Sintilimab, a fully human anti-PD-1 therapeutic monoclonal antibody for cancer

2018 ◽  
Vol 1 (2) ◽  
pp. 65-73 ◽  
Author(s):  
Shuang Zhang ◽  
Min Zhang ◽  
Weiwei Wu ◽  
Zhijun Yuan ◽  
Andy Tsun ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Receptor ◽  
Luciferase Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Tcr Signaling ◽  
Igg Antibody ◽  
Dissociation Kinetics ◽  
Programmed Death

ABSTRACT Background Programmed cell death 1 (PD-1) is an inhibitory immune checkpoint expressed on activatedT cells. Upon the formation of T cell receptor (TCR)-pMHC complexes, concomitant PD-1 ligation to its ligands programmed death-ligand 1 (PD-L1) or programmed death-ligand 2 (PD-L2) downregulates TCR signaling and effector function. Here we describe the preclinical characterization of Sintilimab, a fully human IgG4 antibody that potently blocks PD-1 interactions with PD-L1 and PD-L2. Methods The binding affinity and blockade function were detected by using surface plasmon resonance (SPR), Enzyme-linked immunosorbent assay (ELISA) and flow cytometry. The biology function properties were measured with luciferase assay and mixed lymphocyte reaction assay. In vivo anti-tumor function and preclinical pharmacokinetic (PK) were identified with human PD-1 transgenic mice and non-human primates separately. Results Sintilimab can specifically and strongly bind to human PD-1 (hPD-1) and cynomolgus PD-1 and the affinity of Sintilimab to human PD-1 was measured at 0.3 nm via surface SPR, and displayed slow dissociation kinetics. Sintilimab can block the interaction of PD-1 to PD-L1 and PD-L2 and induce high secretion levels of interferon (IFN)-γ and interleukin (IL)-2 in primary T cell assays. In humanized hPD-1 knock-in mouse models, Sintilimab showed potent anti-tumor activity and increased tumor-infiltrating CD8/CD4 T cell and CD8/ Treg ratios. Preclinical experimentation in non-human primates following a single intravenous infusion of Sintilimab at 1, 6 and 30 mg/kg presented with no signs of drug-related toxicity, and showed typical PK characteristics of an IgG antibody. Conclusions Sintilimab has desirable preclinical attributes that supports its clinical development for cancer treatment.

scholarly journals Degradation of recalcitrant organic polluants in seafood wastewater by modified TiO2 photocatalysts

2017 ◽  
Vol 1 (T4) ◽  
pp. 241-248
Author(s):  
Loc Cam Luu ◽  
Da Linh Ho ◽  
Phu Chi Hoang ◽  
Tri Nguyen ◽  
Van Thi Thuy Nguyen ◽  
...  
Keyword(s):  
Waste Water ◽  
Water Discharge ◽  
Pure Tio2 ◽  
Reaction Conditions ◽  
Tio2 Photocatalysts ◽  
Processing Plants ◽  
Seafood Processing ◽  
The Relationship

In seafood processing plants, industrial waste water discharge reached virtually the level B (QCVN 11-MT:2015/BTNMT) after using mechanical, physicochemical and biological wastewater treatment methods. However, their COD values (COD = 20-120 mg/L) were not qualified for allowable concentration of discharge requirement - level A (COD ≤ 75 mg/L) in many cases. In this paper, bio-treated seafood waster water was continually treated by TiO2 photocatalyst modified by doping Fe and N to degrade recalcitrant organic pollutants to obtain the A level water which can be resused. TiO2 modified by doping Fe and N were prepared and investigated the physico-chemicalproperties. The results showed that modified TiO2 had a lower band gap and more photoactivity than pure TiO2. Beside that, at the reaction conditions: reaction temperature 25 oC, dissolved oxygen concentration 7.6 mg/L and pH = 7, the optimal concentration of catalysts was determined (1.25 g/L). After 12 hours of treatment, COD removal efficiency on TiO2-Fe and TiO2-N catalysts attained 41.1 % and 64.3 %, respectively, and their COD values reached 49.3 and 29.9 mg/L, correspondingly. After treatment, the quality of waste water discharge met the level A (QCVN 11-MT:2015/BTNMT) and became a safety source for reusing (QCVN 08-MT:2015/BTNMT). In addition, the relationship between the characterization of modifed TiO2 and their activity was characterized.

scholarly journals An Unspliced Group I Intron in 23S rRNA LinksChlamydiales, Chloroplasts, and Mitochondria

1999 ◽  
Vol 181 (16) ◽  
pp. 4734-4740 ◽  
Author(s):  
Karin D. E. Everett ◽  
Simona Kahane ◽  
Robin M. Bush ◽  
Maureen G. Friedman
Keyword(s):  
Ribosomal Subunit ◽  
Group I Intron ◽  
23S Rrna ◽  
Rt Pcr ◽  
Naturally Occurring ◽  
Group I ◽  
Ribosomal Function ◽  
Simkania Negevensis

ABSTRACT Chlamydia was the only genus in the orderChlamydiales until the recent characterization ofSimkania negevensis ZT and Parachlamydia acanthamoebae strains. The present study ofChlamydiales 23S ribosomal DNA (rDNA) focuses on a naturally occurring group I intron in the I-CpaI target site of 23S rDNA from S. negevensis. The intron, SnLSU · 1, belonged to the IB4 structural subgroup and was most closely related to large ribosomal subunit introns that express single-motif, LAGLIDADG endonucleases in chloroplasts of algae and in mitochondria of amoebae. RT-PCR and electrophoresis of in vivo rRNA indicated that the intron was not spliced out of the 23S rRNA. The unspliced 658-nt intron is the first group I intron to be found in bacterial rDNA or rRNA, and it may delay the S. negevensis developmental replication cycle by affecting ribosomal function.

scholarly journals Dissociation Mechanics and Stability of Type a Botulinum Neurotoxin Complex by Means of Biophysical Evaluation

2022 ◽  
Author(s):  
Shavron Hada ◽  
Jae Chul Lee ◽  
Eun Chae Lee ◽  
Sunkyong Ji ◽  
Jeong Sun Nam ◽  
...  
Keyword(s):  
Light Scattering ◽  
Botulinum Neurotoxin ◽  
Type A ◽  
Size Exclusion ◽  
Enzyme Linked Immunosorbent Assay ◽  
Biophysical Characterization ◽  
Exclusion Chromatography ◽  
Associated Proteins ◽  
Dissociated State

Abstract Biophysical characterization of type A botulinum neurotoxin (BoNT/A) complex along with its thermodynamic stability was assessed through a combination of various methods. BoNT/A exists as large complexes in association with neurotoxin associated proteins (NAPs). To evaluate its biophysical behavior, size-exclusion chromatography (SEC), multi-angled light scattering (MALS), enzyme linked immunosorbent assay (ELISA), and dynamic light scattering (DLS) were utilized. Initially, a single peak (peak 1) of SEC was observed at pH 6.0, and an additional peak (peak 2) appeared at pH 7.4 with a decrement of peak 1. Through MALS and ELISA, the peak 2 was determined to be BoNT/A dissociated from its complex. The dissociation was accelerated by time and temperature. At 37°C, dissociated BoNT/A self-associated at pH 7.4 in the presence of polysorbate 20. On the other hand, the dissociation was partly reversible when titrated back to pH 6.0. Overall, BoNT/A was more stable when associated with NAPs at pH 6.0 compared to its dissociated state at pH 7.4. The conventional analytical methods could be utilized to relatively quantify its amount in different formulations.

Production and Characterization of Antibodies Against Neosaxitoxin

1992 ◽  
Vol 75 (2) ◽  
pp. 341-345 ◽  
Author(s):  
Fun S Chu ◽  
Xuan Huang ◽  
Sherwood Hall
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Indirect Elisa ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Antibody ◽  
Antibody Titers ◽  
Antibody Elisa

Abstract Antibody against neosaxitoxin (neo-STX) was obtained from rabbits after immunization with neo- STX conjugated to either keyhole limpet hemocyanln (KLH) or bovine serum albumin (BSA). An indirect enzyme-linked Immunosorbent assay (ELISA), In which either neo-STX-BSA or neo-STXKLH was coated to the mlcroplate, was used to monitor the antibody titer. Although high antibody titers were obtained from rabbits after immunization with both immunogens, only antibody obtained from rabbits immunized with neo-STX-KLH was useful for Immunoassay. Competitive indirect ELISA revealed that the antibodies obtained from rabbits Immunized with neo-STX-KLH are specific for neo-STX but also have good cross-reactivity with STX. The concentrations causing 50% inhibition binding of neo-STX-BSA to the anti-neo-KLH by neo-STX, STX, and decarbamoyl-STX (DC-STX) were 0.9,8.0, and 53.1 ng/mL, respectively. Saxitoxin conjugated to polylyslne (STX-PLL) was also used as the coating reagent In the indirect ELISA. The concentrations causing 50% inhibition binding of antl-neo-STX-KLH to STX-PLL coated on the mlcrotiter plate by neo-STX, STX, and DC-STX were 1.2,4.1, and 36.1 ng/mL, respectively. With this newly developed antibody, ELISA could be a very effective method for monitoring seafood for both neo-STX and STX.

scholarly journals Characterization of Serological Responses to Pertussis

2006 ◽  
Vol 13 (3) ◽  
pp. 341-348 ◽  
Author(s):  
Mineo Watanabe ◽  
Beverly Connelly ◽  
Alison A. Weiss
Keyword(s):  
Adenylate Cyclase ◽  
Serological Diagnosis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Vaccine Antigens ◽  
History Of ◽  
Antibody Titers ◽  
Iga Antibody ◽  
Conventional Vaccine ◽  
Culture Positive

ABSTRACT We have compared the use of five nonvaccine antigens to the use of conventional vaccine antigens, pertussis toxin (PT), and filamentous hemagglutinin (FHA) for the serological diagnosis of pertussis by enzyme-linked immunosorbent assay (ELISA). The nonvaccine antigens included the catalytic region of adenylate cyclase toxin (CatACT), the C-terminal region of FHA (C-FHA), lipooligosaccharide (LOS), the peptidoglycan-associated lipoprotein (PAL), and the BrkA protein. The serological responses of individuals with culture-confirmed pertussis were compared to those of adults with no recent history of a coughing disease. An immunoglobulin G (IgG) ELISA for PT was the most sensitive (92.2%) test for the serodiagnosis of pertussis. Of the nonvaccine antigens, ELISA for IgG responses to CatACT (sensitivity, 62.8%), C-FHA (sensitivity, 39.2%), and LOS IgA (sensitivity, 29.4%) were less sensitive but could also distinguish culture-positive individuals from control individuals. The use of a combination of multiple ELISA targets improved the sensitivity of the assay for serological diagnosis. Elevated IgG and IgA antibody titers persisted for more than a year in the individuals with culture-confirmed pertussis.

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