Nucleic acid amplification technologies are used in the field of molecular biology and recombinant DNA technologies. These techniques are used as leading methods in detecting and analyzing a small ...quantity of nucleic acids. The polymerase chain reaction (PCR) is the most widely used method for DNA amplification for detection and identification of infectious diseases, genetic disorders and other research purposes. However, it requires a thermocycling machine to separate two DNA strands and then amplify the required fragment. Novel developments in molecular biology of DNA synthesis in vivo demonstrate the possibility of amplifying DNA in isothermal conditions without the need of a thermocycling apparatus. DNA polymerase replicates DNA with the aid of various accessory proteins. Recent identification of these proteins has enabled development of new in vitro isothermal DNA amplification methods, mimicking these in vivo mechanisms. There are several types of isothermal nucleic acid amplification methods such as transcription mediated amplification, nucleic acid sequence-based amplification, signal mediated amplification of RNA technology, strand displacement amplification, rolling circle amplification, loop-mediated isothermal amplification of DNA, isothermal multiple displacement amplification, helicase-dependent amplification, single primer isothermal amplification, and circular helicase-dependent amplification. In this article, we review these isothermal nucleic acid amplification technologies and their applications in molecular biological studies.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Considering the introduction of aptamers as a new generation of analyte identifiers, this class of materials can be used in diagnostic systems because aptamers are easier to produce, more sensitive, ...higher accuracy, less sensitive to environmental factors, easier to handle and can be used. A special type of aptamer that has sequence rich in guanine base can create a special nanostructure called G-quadraplex. The creation of this structure gives the aptamer an enzyme property so that it can act like an enzyme in the vicinity of it, oxidize a chromogenic substrate and produce a colored signal. The main way to produce aptamers is a laboratory technique called SELEX (Systematic evolution of ligands by exponential enrichment), in which a mixture of different oligo libraries in the vicinity of the target analyte creates aptamers in several consecutive cycles. The aim of this study was the introduction a novel approach for obtaining DNA aptamers for detection a ligand such as aflatoxin M1 in bioinformatically manner in replacing to SELEX for obtaining the specific oligoaptamers against aflatoxin M1. For this purpose, the structure of the selected oligoaptamers were predicted using some molecular simulators and bioinformatically techniques. The results of these molecular simulations suggested G-quadruplex aptamers with suitable affinity for binding to aflatoxin M1 in colorimetric assays.
This paper reviews the best known techniques using circular dichroism spectroscopy such as conventional circular dichroism (i.e. electronic circular dichroism), magnetic circular dichroisms (magnetic ...vibrational circular dichroism, x‐ray magnetic circular dichroism), fluorescence detected circular dichroism, near‐infrared circular dichroism, vibrational circular dichroism, Fourier transform infrared circular dichroism, high pressure liquid chromatography circular dichroism, stopped‐flow circular dichroism, and synchrotron radiation circular dichroism. Also, we have described here the most important applications of circular dichroism spectroscopy in structural biochemistry and nanoscience.
Recently electrospun nanofibers have been fabricated from biodegradable polymers, which received attention due to their applications in various fields such as packaging nanomaterials. In this study,
...Aloe vera
nanofibers which contained
Pseudomonas
sp
.
bacteriophages were fabricated using electrospinning machine. The nanofibers were characterized ultra-structurally using atomic force microscopy (AFM). Mechanical stress of the nanofibers was measured using tensile test system (TTS). Thermodynamical characteristics of the nanofibers were analyzed via
s
imultaneous thermal analyzer (STA). Moreover, the biofunction of the electrospun nanofibers was checked via microbial experiments. The results demonstrated significant changes in the morphology of aloe vera nanofibers after addition of the phages. The roughness parameters and topographical ultra-structures of the aloe vera nanofibers were also changed significantly due to presence of the phages. Also, thermal stability and flexibility of the nanofibers were improved after containing the phage particles, because of higher thermodynamical and mechanical parameters of the phages in comparison to aloe vera substances. The antimicrobial properties of the aloe vera nanofibers which contained bacteriophages were significantly increased due to synergetic antimicrobial properties of the phages when electrospun with the aloe vera nanofibers. These findings suggested the nanofibers as hybrid nanomaterials for employing in food packaging.
During the last years with increasing resistant bacteria to the most antibiotics bacteriophages are suggested as appropriate treatment option. To investigate lytic activity of bacteriophages there ...are indirect microbial procedures and direct methods. The present study to complement microbial procedures and investigate ultra-structural characteristics of infection bacterium-phage use atomic force microscopy technique.
The
bacteriophages were isolated from sewage at the Tertiary Pediatric Hospital. Bacteriophages (10×10
PFU/ml) were diluted and were mixed with 100 μl of methicillin resistant
(MRSA) ATCC 33591 (1.5×10
CFU/ml). The tubes were incubated for 20 min at 37
C, at intervals 10 min, 10 μl samples were removed and directly were investigated MRSA ATCC morphology, roughness parameter, 3D topography, cell height, and fast Fourier transform (FFT) by atomic force microscopy (AFM) technique. Concurrently turbidity assay were performed.
Concentration of MRSA ATCC No. 33591 strain after 10 min in phage-treated MRSA S3 (1.5×10
CFU/ml), S4 (1.5×10
CFU/ml), S5 (1.5×10
CFU/ml), S6 (1.5×10
CFU/ml) decreased 2-log, 3-log, 4-log, and 5-log respectively. The results AFM micrographs shown the most changes in bacterial morphology and 3D topography, destruction of cell wall, decrease of cell height, and loss of their shape after 10 min at phage-treated MRSA S3 (1.5×10
CFU/ml), S4 (1.5×10
CFU/ml), S5 (1.5×10
CFU/ml), S6 (1.5×10
CFU/ml) respectively .
In this study MRSA ATCC ultra-structural changes in phage-treated MRSA ATCC groups directly were detected using AFM technique.
This study describes the fabrication techniques for two forms of magnetic DNA nanotubes (MDNTs) and their applications as platforms for developing colorimetric assays. The first form of MDNTs was ...DNTs filled-up with magnetic nanoparticles (MNPs) and the second one was DNTs arayed with MNPs on their extrior surfaces. Then the both forms of MDNTs were employed as platforms for attaching a specific insulin aptamer. The sensitivity and accuracy of the insulin measurement using both platforms were studied and compared with enzyme-linked immunosorbent assay (ELISA) as the standard method for the measurement of insulin in cliniccal laboratories. Applying the magnetic field to MDNTs led to enhance the ability of insulin capturing by the aptamer array in serum and subsequently by removing unspecified contents led to precised detection. For specific detection of insulin and its measurement in this study, a G-rich DNA aptamer with HRP-mimicking activity was used that simulated the peroxidase performance when the insulin was trapped with the aptamer. The presence of MDNTs made a high flexibility, a greater convergence of the connectivity to superficial aptamers, and hence the availability of these aptamers to increase the target molecules and subsequently increased the sensitivity of the measurements. This colorimetric method can be used as a novel biosensores for detection of any target molecules.
Context: Spread of Methicillin-resistant Staphylococcus aureus (MRSA) can cause serious and sometimes fatal diseases especially in children. Outbreaks and increasing the prevalence of ...antibiotic-resistant MRSA at pediatric hospital calls for the development of novel preservation techniques. Endolysins and bacteriophages have been used successfully to control bacterial infections in children. Endolysins were considered as a useful treatment especially for the pathogens without disturbing the normal flora, the low chance of bacterial resistance, and their ability to kill colonizing pathogens on mucosal surfaces. Herein, we aimed to review the effectiveness of endolysins of bacteriophage for controlling methicillin-resistant Staphylococcus aureus infections in children. Evidence Acquisition: This review was performed by searching studies indexed in international databases including PubMed, Scopus, Web of Science, Science Direct, as well as Google Scholar published from 2000 until 2016. Results: Experimental data show that endolysins of Staphylococcus aureus bacteriophage can be used to combat methicillin-resistant Staphylococcus aureus infections in children. Conclusions: Endolysins of bacteriophages could be effective for controlling a variety of methicillin-resistant Staphylococcus aureusinfections.
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Nowadays, the detection of albumin and determination of its concentration for early diagnosis of kidney diseases has attracted considerable attention as a simple and rapid method. In ...this work, two methods for detection and determination of albumin concentration were investigated and compared by using gold nanorods (GNRs) and spectrophotometry of their interaction with bovine serum albumin (BSA).
By the changes in the typical synthesis protocol, GNRs' samples were synthesized and characterized. Synthesized GNRs were mixed with different concentrations of BSA. Ultraviolet–Visible (UV–Vis) spectroscopy and X-ray Fluorescence (FL) spectroscopy were applied to examine the mixed samples. The change of absorption spectrum in the UV region showed the detection limit of BSA concentration of 0.2 mg/mL. The detection limit of BSA concentration of 0.05 mg/mL was obtained from the investigation of absorption spectrum in visible-infrared (Vis-IR) regions. However, the study of the FL spectra proved the detection limit is as low as 0.0013 mg/mL. Therefore, it was found out that very low concentrations of albumin could be very accurately detected by FL spectroscopy. Also, comparing of the spectra obtained from the samples at various time intervals indicated that the measurement of concentration is possible after 1–20 min of mixing GNRs and BSA.
We describe a microfluidic method for rapid isothermal turbidimetric detection of the DNA of
Mycobacterium tuberculosis
. Loop-mediated isothermal amplification is accomplished in capillary tubes for ...amplifying DNA in less than 15 min, and sensitivity and specificity were compared to conventional loop-mediated isothermal amplification (LAMP). The method can detect as little as 1 pg mL
−1
DNA in a sample. Results obtained with clinical specimens indicated 90 % sensitivity and 95 % specificity for microfluidic LAMP in comparison to culture methods. No interference occurred due to the presence of nonspecific DNAs. The findings demonstrate the power of the new microfluidic LAMP test for rapid molecular detection of microorganisms even when using bare eyes.
Graphical abstract
We describe a microfluidic method for rapid isothermal turbidimetric detection of the DNA of
Mycobacterium tuberculosis
. Loop-mediated isothermal amplification (LAMP) is accomplished in capillary tubes for amplifying DNA in less than 15 min. The findings demonstrate the power of the new microfluidic LAMP test for rapid molecular detection of microorganisms even when using bare eyes.
This paper reviews the best-known differential scanning calorimetries (DSCs), such as conventional DSC, microelectromechanical systems-DSC, infrared-heated DSC, modulated-temperature DSC, gas ...flow-modulated DSC, parallel-nano DSC, pressure perturbation calorimetry, self-reference DSC, and high-performance DSC. Also, we describe here the most extensive applications of DSC in biology and nanoscience.
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