scholarly journals Sintesis antigen AFB1-BSA dan konjugasi antibodi anti AFB1-BSA dengan nanopartikel emas sebagai pereaksi imunostrip

2021 ◽  
Vol 4 (4) ◽  
pp. 77-78
Author(s):  
Ita Krissanti ◽  
Agustin Indrawati ◽  
Romsyah Maryam

Aflatoksin B1 (AFB1) often contaminates a great variety of foods and animal feeds that will be dangerous if con-sumed by humans or animals.  Rapid detection techniques that can be used in the field is really needed to monitor AFB1 contamination.  The aims of this study were to perform synthesis of AFB1-BSA antigen and conjugation of antibody against AFB1-BSA to gold nanoparticle as immunostrip-test reagents. The AFB1-CMO was identified on TLC and AFB1-BSA was characterized using SDS PAGE. The AFB1-CMO formation indicated as a blue spot at 0.45 retention factor (Rf) on TLC and the AFB1-BSA antigen revealed as a single band protein at about 72 kDa molecular weight on the SDS PAGE.  Conjugation of antibody against AFB1-BSA to gold nanoparticle resulted in the formation of red-dish purple compound which can be used for the detection of AFB1 on immunostrip. The optimum composition achieved in concentration of AFB1-BSA 1-1.5 mg/ml, IgG anti rabbit 0.1 mg/ml, and antibody against AFB1-BSA-gold nanoparticle conjugate in 0.5x0.5 cm² area characterized by the establishment of two reddish purple lines in the test and control zone.

1987 ◽  
Vol 33 (7) ◽  
pp. 614-618 ◽  
Author(s):  
Mary Giblin ◽  
Catherine T. Kelly ◽  
William M. Fogarty

Bacillus caldovelox produces an intracellular α-glucosidase (EC 3.2.1.20). It is the most thermostable microbial α-glucosidase reported to date and a number of its properties are outlined here. It was purified by treatment with protamine sulphate and gel filtration on Sephadex G-150 and gave a single band on SDS–PAGE. The enzyme had highest activity on p-nitrophenyl-α-D-glucoside, which was 2.04 times higher than the activity on maltose, and it was inactive towards isomaltose. It had a molecular weight of 30 000 and an isoelectric point of pH 5.0. The enzyme operated most efficiently at pH 5.5–6.0 and at 50–60 °C. It possessed considerable pH stability, retaining 80% or more activity in the range pH 4.0–9.0. α-Glucosidases tend to be very unstable, but this enzyme was fully stable up to 60 °C for 1 h and retained 51% of its original activity on incubation at 70 °C over the same period. The presence of histidine, cysteine, and manganous ions improved the thermal stability of the enzyme considerably. EDTA, α,α′-dipyridyl, o-phenanthroline, barium, strontium, manganous ions, and glucose stimulated activity, while Tris, ribose, glucono-δ-lactone, and phenyl-α-D-glucoside inhibited activity.


2020 ◽  
Vol 9 (1) ◽  
pp. 30
Author(s):  
Mochammad Sriduresta Soenarno ◽  
Irma Isnafia Arief ◽  
Cece Sumantri ◽  
Epi Taufik ◽  
Lilis Nuraida

Bakteriosin adalah peptida dengan aktivitas antibakteri yang diproduksi oleh bakteri asam laktat dan digunakan sebagai pengawet alami. Penelitian sebelumnya menunjukkan bahwa Lactobacillus plantarum IIA-1A5 memproduksi bakteriosin yang diberi nama Plantarisin IIA-1A5 pada medium pertumbuhan yang dibuat dari whey yang diperkaya skim. Untuk aplikasi sebagai pengawet alami dan untuk memperbaiki masa simpan dan aktivitas anti mikrobanya, plantarisin perlu dienkapsulasi dan dikeringbekukan. Tujuan dari penelitian ini adalah untuk mengkarakterisasi dan mengevaluasi aktivitas antimikroba dari sediaan plantarisin IIA-1A5 yang terpurifikasi parsial dan terenkapsulasi kering beku. Ekstraksi dan purifikasi dari bakteriosin dimulai dengan presipitasi dengan ammonium sulfat, yang diikuti dengan dialysis, dan penukar kation kromatografi. Purifikasi parsial dari plantarisin kemudian dimikroenkapsulasi dengan maltodextrin kemudian dilanjutkan dengan proses kering beku. Berdasarkan pada SDS-PAGE, fraksi protein ke-7 (F7) dari plantarisin yang dipurifikasi parsial memiliki pita tunggal dan berat molekul sekitar 9,65 kDa. Konfirmasi lebih lanjut dengan menggunakan MALDI-TOF MS, ternyata pita tunggal tersebut terdiri dari 5 peptida yang diidentifikasi berbobot molekul masing-masing sebagai berikut 5,5, 7,80, 7,96, 9,09, dan 9,27 kDa. Plantarisin kering beku memiliki aktivitas antimikroba terhadap Staphylococcus  aureus tiga kali lipat dibandingkan dengan aktivitas antimikroba dari supernatan bebas sel, dan lebih tinggi dibandingkan dengan nisin, namun kurang bila dibandingkan dengan antibiotik ampisilin dan penisilin. Kesimpulannya, aktivitas antimikroba plantarisin kering beku dapat ditentukan dan lebih tinggi dibandingkan dengan nisin, ampisilin dan penisilin.Characterization of Plantarisin IIA-1A5 as Antimicrobial subtances and Evaluation of Acitivity of Freeze-dried Microencapsulated PreparationAbstractBacteriocins are peptides with antibacterial activity produced by lactic acid bacteria and used as natural preservatives. Previous studies showed that Lactobacillus plantarum IIA-1A5 produces bacteriocin named plantaricin IIA-1A5 in the medium consisting whey enriched with skim milk. For application as food preservatives and to improve its shelf-lie and activity, plantaricin was needed to be microencapsulated and freeze dried. The objective of this research was to characterize and evaluate the activity of partially purified freeze dried microencapsulated plantaricin IIA-1A5. Characterisation of partially purified plantaricin IIA-IA5 includes the identification of active fractions and molecular weight, evaluation of activity at different stage of purification and evaluation of antimicrobial activity of freeze dried microencapsulated plantaricin IIA-IA5. Extraction and prificafication of the bacteriocins started with precipitacion with ammonium sulfate, followed by dialysis, and cation exchange chromatography. The partial purified of plantaricin was then microencapsulated in maltodextrin followed by freeze drying. Based on SDS-PAGE, the protein fraction F7 of partially purified plantaricin had a single band and molecular weight about 9.65 kDa. Further analyses using MALDI-TOF, it revealed that five peptides were identified from one single band plantaricin with molecular weight 5.5, 7.80, 7.96, 9.09, and 9.27 kDa, respectively. The freeze dried plantaricin freeze showed antimicrobial activity against Staphylococcus aureus three times stringer as compared to the activity of cell free supernatant, and was higher than nicin, but less than antibiotic ampicilin and penicilin. As concusion, the activity of freeze dried plantaricin could be determined and had a higher value than nicin, ampicilin and penicilin.


2015 ◽  
Vol 63 (2) ◽  
Author(s):  
Yingyin Xu ◽  
Yuxiao Lu ◽  
Rui Zhang ◽  
Hexiang Wang ◽  
Qinghong Liu

A novel laccase was purified from the white rot fungus, Hohenbuehelia serotina, to investigate the applications of this laccase in the decoloration of various dyes. SDS-PAGE revealed a single band of this laccase corresponding to a molecular weight of approximately 57.8 kDa. The enzyme showed activity towards several substrates, the most sensitive of which was 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS). The highest enzymatic activity using ABTS as a substrate was observed at pH 6.8 and 30°C. The enzyme activity was found to be significantly enhanced in the presence of Zn(2+) ions and inhibited by Fe(2+) ions. Moreover, SDS and β-mercaptoethanol were inhibitory, and inhibition by L-cysteine was observed while EDTA and DMSO had almost no inhibitory effect. The laccase could effectively decolorize seven different dyes within 30 minutes at 40°C.


1999 ◽  
Vol 82 (11) ◽  
pp. 1428-1432 ◽  
Author(s):  
Cheryl Scott ◽  
Francesco Salerno ◽  
Elettra Lorenzano ◽  
Werner Müller-Esterl ◽  
Angelo Agostoni ◽  
...  

SummaryLittle is known about the regulation of high-molecular-weight-kininogen (HK) and low-molecular-weight-kininogen (LK) or the relationship of each to the degree of liver function impairment in patients with cirrhosis. In this study, we evaluated HK and LK quantitatively by a recently described particle concentration fluorescence immunoassay (PCFIA) and qualitatively by SDS PAGE and immunoblotting analyses in plasma from 33 patients with cirrhosis presenting various degrees of impairment of liver function. Thirty-three healthy subjects served as normal controls. Patients with cirrhosis had significantly lower plasma levels of HK (median 49 μg/ml [range 22-99 μg/ml]) and LK (58 μg/ml [15-100 μg/ml]) than normal subjects (HK 83 μg/ml [65-115 μg/ml]; LK 80 μg/ml [45-120 μg/ml]) (p < 0.0001). The plasma concentrations of HK and LK were directly related to plasma levels of cholinesterase (P < 0.0001) and albumin (P < 0.0001 and P < 0.001) and inversely to the Child-Pugh score (P < 0.0001) and to prothrombin time ratio (P < 0.0001) (reflecting the clinical and laboratory abnormalities in liver disease). Similar to normal individuals, in patients with cirrhosis, plasma HK and LK levels paralleled one another, suggesting that a coordinate regulation of those proteins persists in liver disease. SDS PAGE and immunoblotting analyses of kininogens in cirrhotic plasma showed a pattern similar to that observed in normal controls for LK (a single band at 66 kDa) with some lower molecular weight forms noted in cirrhotic plasma. A slight increase of cleavage of HK (a major band at 130 kDa and a faint but increased band at 107 kDa) was evident. The increased cleavage of HK was confirmed by the lower cleaved kininogen index (CKI), as compared to normal controls. These data suggest a defect in hepatic synthesis as well as increased destructive cleavage of both kininogens in plasma from patients with cirrhosis. The decrease of important regulatory proteins like kininogens may contribute to the imbalance in coagulation and fibrinolytic systems, which frequently occurs in cirrhotic patients.


1992 ◽  
Vol 68 (05) ◽  
pp. 534-538 ◽  
Author(s):  
Nobuhiko Yoshida ◽  
Shingi Imaoka ◽  
Hajime Hirata ◽  
Michio Matsuda ◽  
Shinji Asakura

SummaryCongenitally abnormal fibrinogen Osaka III with the replacement of γ Arg-275 by His was found in a 38-year-old female with no bleeding or thrombotic tendency. Release of fibrinopeptide(s) by thrombin or reptilase was normal, but her thrombin or reptilase time in the absence of calcium was markedly prolonged and the polymerization of preformed fibrin monomer which was prepared by the treatment of fibrinogen with thrombin or reptilase was also markedly defective. Propositus' fibrinogen had normal crosslinking abilities of α- and γ-chains. Analysis of fibrinogen chains on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the system of Laemmli only revealed the presence of abnormal γ-chain with an apparently higher molecular weight, the presence of which was more clearly detected with SDS-PAGE of fibrin monomer obtained by thrombin treatment. Purified fragment D1 of fibrinogen Osaka III also seemed to contain an apparently higher molecular weight fragment D1 γ remnant on Laemmli gels, which was digested faster than the normal control by plasmin in the presence of [ethy-lenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA).


1989 ◽  
Vol 61 (03) ◽  
pp. 437-441 ◽  
Author(s):  
Cindra Condra ◽  
Elka Nutt ◽  
Christopher J Petroski ◽  
Ellen Simpson ◽  
P A Friedman ◽  
...  

SummaryThe present work reports the discovery and charactenzation of an anticoagulant protein in the salivary gland of the giant bloodsucking leech, H. ghilianii, which is a specific and potent inhibitor of coagulation factor Xa. The inhibitor, purified to homogeneity, displayed subnanomolar inhibition of bovine factor Xa and had a molecular weight of approximately 15,000 as deduced by denaturing SDS-PAGE. The amino acid sequence of the first 43 residues of the H. ghilianii derived inhibitor displayed a striking homology to antistasin, the recently described subnanomolar inhibitor of factor Xa isolated from the Mexican leech, H. officinalis. Antisera prepared to antistasin cross-reacted with the H. ghilianii protein in Western Blot analysis. These data indicate that the giant Amazonian leech, H. ghilianii, and the smaller Mexican leech, H. officinalrs, have similar proteins which disrupt the normal hemostatic clotting mechanisms in their mammalian host’s blood.


2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Kate Highnam ◽  
Domenic Puzio ◽  
Song Luo ◽  
Nicholas R. Jennings

AbstractBotnets and malware continue to avoid detection by static rule engines when using domain generation algorithms (DGAs) for callouts to unique, dynamically generated web addresses. Common DGA detection techniques fail to reliably detect DGA variants that combine random dictionary words to create domain names that closely mirror legitimate domains. To combat this, we created a novel hybrid neural network, Bilbo the “bagging” model, that analyses domains and scores the likelihood they are generated by such algorithms and therefore are potentially malicious. Bilbo is the first parallel usage of a convolutional neural network (CNN) and a long short-term memory (LSTM) network for DGA detection. Our unique architecture is found to be the most consistent in performance in terms of AUC, $$F_1$$ F 1 score, and accuracy when generalising across different dictionary DGA classification tasks compared to current state-of-the-art deep learning architectures. We validate using reverse-engineered dictionary DGA domains and detail our real-time implementation strategy for scoring real-world network logs within a large enterprise. In 4 h of actual network traffic, the model discovered at least five potential command-and-control networks that commercial vendor tools did not flag.


2013 ◽  
Vol 838-841 ◽  
pp. 30-35
Author(s):  
Xiao Bin Sun ◽  
Tian Ling Du ◽  
Bo Tian

With regards to the quality problem of concrete that cant be found out earlier in the quality control, this paper discussed the principle to rapidly detect composition of concrete mixture and analyzed the measurement accuracy of water checker for fresh concrete through laboratory test. Experiments showed that the error in unit cement and unit water measured by instruments is relatively small and able to meet the accuracy requirements. And, the application of rapid detection techniques to the concrete quality control in practical engineering has achieved good results.


Author(s):  
Tae Ito ◽  
Yuko Suzuki ◽  
Hideto Sano ◽  
Naoki Honkura ◽  
Francis J Castellino ◽  
...  

Background: Details of the molecular interaction between tissue type plasminogen activator (tPA) and plasminogen activator inhibitor type-1 (PAI-1) remain unknown. Methods and Results: Three distinct forms of high molecular weight complexes are demonstrated. Two of the forms were detected by mass spectrometry. The high molecular mass detected by MALDI-TOF MS spectrometry was 107,029 Da, which corresponds to the sum of molecular masses of the intact tPA (65,320 Da) and the intact PAI-1 (42,416 Da). The lower molecular mass was 104,367 Da and is proposed to lack the C-terminal bait peptide of PAI-1 (calculated mass, 3,804 Da) which was detected as a 3,808 Da fragment. When the complex was analyzed by SDS-PAGE, only a single band was observed. However, after treatment by SDS and Triton X-100, two distinct forms of the complex with different mobilities were shown by SDS-PAGE. The higher molecular weight band demonstrated specific tPA activity on fibrin autography, whereas the lower molecular weight band did not. Peptide sequence analysis of these two bands, however, unexpectedly revealed the existence of the C-terminal cleavage peptide in both bands and its amount was less in the upper band. In the upper band, the sequences corresponding to the regions at the interface between two molecules in its Michaelis intermediate were diminished. Thus, these two bands corresponded to distinct nonacyl-enzyme complexes, wherein only the upper band liberated free tPA under the conditions employed. Conclusion: These data suggest that under physiological conditions a fraction of the tPA-PAI-1 population exists as non-acylated-enzyme inhibitor complex.


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