Complementary Sequences Research Articles

Proton-Mediated Dynamic Nestling of DNA Payloads Within Size-Matched MOFs Nanochannels for Smart Intracellular Delivery.

With sequence-programmable biological functions and excellent biocompatibility, synthetic functional DNA holds great promise for various biological applications. However, it remains a challenge to simultaneously retain their biological functions while protecting these fragile oligonucleotides from the degradation by nucleases abundant in biological circumstances. Herein, a smart delivery system for functional DNA payloads is developed based on proton-mediated dynamic nestling of cytosine-rich DNA moieties within the precisely size-matched nanochannels of highly crystalline metal-organic frameworks (MOFs): At neutral pH, cytosine-rich DNA strands exhibit a flexible single-stranded state and can be accommodated by MOFs nanochannels with a size of ca. 2.0nm; while at acidic conditions, the protonation of cytosine-rich strands weakens their interaction with the nanochannels, and the tendency to form four-strandedstructures drives these DNA strands out of the nanochannels. Results confirm the successful protection of DNA payloads from enzymatic hydrolysis by the MOFs nanochannels, and the delicate coupling of the endocytosis processes and the proton-responsive Cytosine-rich DNA/MOFs systems realized the efficient intracellular delivery of DNA payloads. Furthermore, with a complementary sequence to the telomere overhangs, direct imaging of telomeres and the nucleus is successfully achieved with the proton-mediated DNA/MOFs system.

Field-Based cDNA-Biosensor for Accurate Detection of Canine Distemper Virus in Tissue Samples.

Canine distemper, a viral disease with a global impact on various animals including dogs, foxes, wolves, lions, and leopards, requires early diagnosis for effective treatment and outbreak control. Common laboratory methods, such as enzyme-linked immunosorbent assay, polymerase chain reaction, and viral isolation, face challenges such as extended turnaround times, high costs, and the expertise required. This study has developed a field-based biosensor for detecting the canine distemper virus (CDV), utilising a screen-printed carbon electrode (SPCE) and a computer-assisted portable potentiostat. A 30-mer oligonucleotide capture probe, designed using Primer3 Plus software version 3.3.0, detected hybridisation with the CDV complementary strand through electrochemical analysis via differential pulsed voltammetry. The developed biosensor exhibited good linearity in quantifying the target analyte concentration (0.1 to 12.8µM), with a detection limit of 0.05µM, indicating high sensitivity. Specificity tests using complementary and non-complementary sequences confirmed the biosensor's accuracy. The electrode can be reused up to eight times with a residual capacity of 93.72 ± 5.45% after regeneration using a 50mM NaOH solution. The developed biosensor was also used to detect CDV in biological samples after RNA extraction and amplification. Results from the biosensor aligned with those from reverse transcriptase polymerase chain reaction (RT-PCR) findings, showing 100% agreement. These findings support the potential development of a field-deployable portable device for effectively diagnosing canine distemper in biological samples.

Enzyme-free and highly sensitive detection of human epidermal growth factor receptor-2 based on MNAzyme signal amplification in breast cancer.

As a common cancer biomarker, human epidermal growth factor receptor-2 (HER2) is highly expressed in breast cancer. Consequently, developing a simple and accurate HER2 sensing platform is of great significance for early diagnosis and treatment of breast cancer. Herein, we developed a rapid enzyme-free fluorescent assay biosensor based on MNAzyme signal amplification for breast cancer biomarker, HER2. The MNAzyme consists of multiple parts, including complementary DNA (cDNA) and two parts of DNAzyme (partzyme A/B). Initially, cDNA is blocked by combining with the HER2 aptamer to form a double-stranded DNA. When HER2 is present, cDNA is released as a result of the binding between HER2 and its aptamer. Due to the complementary sequences among cDNA and partzyme A/B, the MNAzyme is successfully assembled to cleave the substrate, recovering the fluorescence output. The MNAzyme biosensor exhibited a low detection limit of 0.02 ng mL-1 and excellent selectivity. Furthermore, the proposed biosensor can also change the recognition element by changing the aptamer sequence to detect various biomarkers, holding great potential for cancer diagnosis and other related biomedical applications.

Deep learning method for detecting fluorescence spots in cancer diagnostics via fluorescence in situ hybridization

Fluorescence in Situ Hybridization (FISH) is a technique for macromolecule identification that utilizes the complementarity of DNA or DNA/RNA double strands. Probes, crafted from selected DNA strands tagged with fluorophore-coupled nucleotides, hybridize to complementary sequences within the cells and tissues under examination. These are subsequently visualized through fluorescence microscopy or imaging systems. However, the vast number of cells and disorganized nucleic acid sequences in FISH images present significant challenges. The manual processing and analysis of these images are not only time-consuming but also prone to human error due to visual fatigue. To overcome these challenges, we propose the integration of medical imaging with deep learning to develop an automated detection system for FISH images. This system features an algorithm capable of quickly detecting fluorescent spots and capturing their coordinates, which is crucial for evaluating cellular characteristics in cancer diagnosis. Traditional models struggle with the small size, low resolution, and noise prevalent in fluorescent points, leading to significant performance declines. This paper offers a detailed examination of these issues, providing insights into why traditional models falter. Comparative tests between the YOLO series models and our proposed method affirm the superior accuracy of our approach in identifying fluorescent dots in FISH images.

C-Reactive Protein Biosensor for Diagnosing Infections Caused by Orthopedic Trauma.

Infections linked to orthopedic trauma are common complications that place a significant strain on the healthcare system. Immediate identification of the infection and its severity is essential for providing effective treatment. C-reactive Protein (CRP) is a commonly used inflammatory marker in orthopedic surgery and has proven to be a valuable biomarker for diagnosing and monitoring infections. Specifically, CRP aids in the early identification of postoperative infections. This research work has focused on developing a highly sensitive CRP biosensor using iron oxide nanomaterial-modified dielectric sensors. Gold Urchin (GU)-conjugated aptamers and antibodies were used as probes and attached to the electrode via amine linkers. The aptamer-GU-antibody-modified electrode detected CRP at concentrations as low as 1 pg/mL, with an R2 value of 0.9942. Furthermore, CRP-spiked serum exhibited an increase in current response at all concentrations of CRP, indicating selective detection of CRP. Additionally, control experiments using complementary sequences of the aptamer, relevant proteins, and non-immune antibodies did not enhance the current responses, confirming the specific identification of CRP. The sensing strategy has enabled the detection of CRP at its lowest levels, facilitating the identification of infections during orthopedic surgery and subsequent treatment.

CircPCNXL2 promotes preeclampsia progression by suppressing trophoblast cell proliferation and invasion via miR-487a-3p/interferon regulatory factor 2 axis.

Preeclampsia (PE) has culminated in maternal and perinatal sickness and death across the world, affecting approximately 4.6% of pregnancies. Circular RNAs (circRNAs) have been linked to the biology of numerous pathologies, including PE. Here, we investigated the functional role of circPCNXL2 in the progression of PE. We employed the GEO database to get the expression profile of circPCNXL2 in patients with PE. This was followed by the detection of the expression of circPCNXL2 and miR-326 by qRT-PCR. The role of circPCNXL2 on trophoblast cell proliferation, migration, and invasion was confirmed with cell viability assays, the transwell assay, and the colony formation assay. Further, we employed dual luciferase, FISH, RNA pull-down assay and Western blot analysis to determine the interaction between the expression of circPCNXL2, miR-487a-3p, and IRF2. Findings from this study revealed that proliferation and migration of trophoblast cells were significantly increased in the HTR-8/SVneo cells after silencing circPCNXL2. Additionally, knockdown of circPCNXL2 remarkably increased miR-487a-3p expression, while IRF2 expression was remarkably reduced (P < 0.05), indicating the presence of complementary binding sequence on miR-487a-3p with which they sequester circPCNXL2. Rescue experiments revealed that interaction occurs between circPCNXL2, miR-487a-3p, and the IRF2 protein, indicating that circPCNXL2 expression elicits suppression of migration and proliferation of trophoblast cells via the miR-487a-3p/IRF2 pathway. We demonstrated that circPCNXL2 upregulation promotes pre-eclampsia by inhibiting proliferation and migration of trophoblast cells via the miR-487a-3p/IRF2 pathway or axis.

Split G-Quadruplex Programmed Recyclable AIE-Biosensor for Label-Free Detection of miRNA in Acute Kidney Injury.

We herein rationally designed a target-recyclable AIE-biosensor based on a split G-quadruplex for label-free detection of miRNA in acute kidney injury. Initially, the PG was in an "OFF" state, and the two split segments (G4-a and G4-b) of G4 were tethered at the two terminals of P1 and far away from each other due to the rigid duplex structure formed by the partially complementary intermediate sequences of P2 and P1, bringing MG with quenched fluorescence. In the presence of target, the 5'-PO4 P2 was displaced from PG probe and competitively hybridized with target, which led to G4-a and G4-b tending to form an intact intermolecular G-quadruplex, providing sites for MG intercalation, thus generating an activated "ON" fluorescence signal due to the restriction of intermolecular motion. Successively, relying on the λ-exonuclease (λ-Exo) cleavage reaction-assisted target recycling, more amounts of targets will be liberated, accompanied by forming more G-quadruplex and binding more MG, resulting in a strong fluorescence signal, further realizing the sensitive detection of the targets. As a proof of concept, miRNA-21 was chosen as the model target. Endowing with the precise target recognition and efficient cleavage activity of λ-Exo, the AIE-biosensor exhibited excellent detection sensitivity and specificity, which could quantitatively detect miRNA-21 down to 10.36 fM with a single mismatch specificity. The results revealed that the distinctive attributes of noninvasive, simple, and efficient in this G-quadruplex-based AIE-biosensor offered promising prospects for extensive applications in AKI screening and early clinical diagnosis.

Multimodal Pre-training for Sequential Recommendation via Contrastive Learning

Sequential recommendation systems often suffer from data sparsity, leading to suboptimal performance. While multimodal content, such as images and text, has been utilized to mitigate this issue, its integration within sequential recommendation frameworks remains challenging. Current multimodal sequential recommendation models are often unable to effectively explore and capture correlations among behavior sequences of users and items across different modalities, either neglecting correlations among sequence representations or inadequately capturing associations between multimodal data and sequence data in their representations. To address this problem, we explore multimodal pre-training in the context of sequential recommendation, with the aim of enhancing fusion and utilization of multimodal information. We propose a novel Multimodal Pre-training for Sequential Recommendation (MP4SR) framework, which utilizes contrastive losses to capture the correlation among different modality sequences of users, as well as the correlation among different modality sequences of users and items. MP4SR consists of three key components: (1) multimodal feature extraction; (2) a backbone network, Multimodal Mixup Sequence Encoder (M 2 SE); and (3) pre-training tasks. After utilizing pre-trained encoders to generate initial multimodal features of items, M 2 SE adopts a complementary sequence mixup strategy to fuse different modality sequences, and leverages contrastive learning to capture modality interactions at the sequence-to-sequence and sequence-to-item levels. Extensive experiments on four real-world datasets demonstrate that MP4SR outperforms state-of-the-art approaches in both normal and cold-start settings. We further highlight the efficacy of incorporating multimodal pre-training in sequential recommendation representation learning, serving as an effective regularizer and optimizing the parameter space for the recommendation task.

A measles virus collective infectious unit that caused lethal human brain disease includes many locally restricted and few widespread copy-back defective genomes.

During virus replication in cultured cells, copy-back defective viral genomes (cbDVGs) can arise. CbDVGs are powerful inducers of innate immune responses in vitro, but their occurrence and impact on natural infections of human hosts remain poorly defined. We asked whether cbDVGs were generated in the brain of a patient who succumbed to subacute sclerosing panencephalitis (SSPE) about 20 years after acute measles virus (MeV) infection. Previous analyses of 13 brain specimens of this patient indicated that a collective infectious unit (CIU) drove lethal MeV spread. In this study, we identified 276 replication-competent cbDVG species, each present in over 100 copies in the brain. Six species were detected in multiple forebrain locations, implying that they travelled long-distance with the CIU. The cbDVG to full-length genomes ratio was often close to 1 (0.6-1.74). Most cbDVGs were 324-2,000 bases in length, corresponding to 2%-12% of the full-length genome; all are predicted to have complementary terminal sequences. If improperly encapsidated, these sequences have the potential to form double-stranded structures that can induce innate immune responses. To assess this, we examined the transcriptome of all brain specimens. Several interferon and inflammatory response genes were upregulated, but upregulation levels did not correlate with cbDVG levels in the specimens. Thus, the CIU that drove MeV pathogenesis in this brain includes, in addition to two complementary full-length genome populations, many locally restricted and few widespread cbDVG species. The widespread cbDVG species may have been positively selected but how they impacted pathogenesis remains to be determined.IMPORTANCECopy-back defective viral genomes (cbDVGs) can drive virus-host interactions. They can suppress virus replication directly, by competing with full-length genomes, or indirectly by stimulating antiviral immunity. In vitro, cbDVG can slow down infections and promote persistence, but there is limited documentation of their presence in human hosts or of their impact on disease. We had the unique opportunity to analyze the brain of a patient who succumbed to subacute sclerosing panencephalitis, a rare but lethal consequence of measles. We detected more than 270 distinct cbDVG species; most were restricted to one specimen, but several reached all lobes of the forebrain, suggesting positive selection. Our analyses provide the missing knowledge of the diversity of cbDVG in a natural infection of a human host. They also reveal that a collective infectious unit that caused lethal human brain disease includes few widespread cbDVG, in addition to two ubiquitous complementary full-length genome populations.

Sequentially Activated-Dumbbell DNA Nanodevices for Accurate Detection of Uracil-DNA Glycosylase via PER-Based Orthogonal Signal Outputs.

Accurate and reliable detection of uracil-DNA glycosylase (UDG) activity is crucial for clinical diagnosis and prognosis assessment. However, current techniques for accurately monitoring UDG activity still face significant challenges due to the single input or output signal modes. Here, we develop a sequentially activated-dumbbell DNA nanodevice (SEAD) that enables precise and reliable evaluation of UDG activity through primer exchange reactions (PER)-based orthogonal signal output. The SEAD incorporates a double-hairpin structure with a stem containing two deoxyuridine (dU) sites for target recognition and two preblocked primer binding regions for target amplification and signal output. Upon UDG recognition of dU, the SEAD can be cleaved by apurinic/apyrimidinic endonuclease 1 (APE1), generating two different hairpins with exposed primer binding regions. These hairpins serve as templates to initiate the parallel PER, enabling the extending of two different amplification products: a long single-stranded DNA (ssDNA) with repetitive sequences and a short ferrocene-labeled ssDNA with complementary sequences. These products further self-assemble into DNA nano-strings in an orthogonal manner that act as an electrochemiluminescence signal switch, enabling precise detection of low-abundance UDG. This work develops a sequential input and orthogonal output strategy for accurately monitoring UDG activity, highlighting the significant potential in cancer diagnosis and treatment.

Tetramerization-dependent activation of the Sir2-associated short prokaryotic Argonaute immune system

Eukaryotic Argonaute proteins (eAgos) utilize short nucleic acid guides to target complementary sequences for RNA silencing, while prokaryotic Agos (pAgos) provide immunity against invading plasmids or bacteriophages. The Sir2-domain associated short pAgo (SPARSA) immune system defends against invaders by depleting NAD+ and triggering cell death. However, the molecular mechanism underlying SPARSA activation remains unknown. Here, we present cryo-EM structures of inactive monomeric, active tetrameric and active NAD+-bound tetrameric SPARSA complexes, elucidating mechanisms underlying SPARSA assembly, guide RNA preference, target ssDNA-triggered SPARSA tetramerization, and tetrameric-dependent NADase activation. Short pAgos form heterodimers with Sir2-APAZ, favoring short guide RNA with a 5′-AU from ColE-like plasmids. RNA-guided recognition of the target ssDNA triggers SPARSA tetramerization via pAgo- and Sir2-mediated interactions. The resulting tetrameric Sir2 rearrangement aligns catalytic residue H186 for NAD+ hydrolysis. These insights advance our understanding of Sir2-domain associated pAgos immune systems and should facilitate the development of a short pAgo-associated biotechnological toolbox.

Reliable Majority Vote Computation With Complementary Sequences for UAV Waypoint Flight Control

Reliable Majority Vote Computation With Complementary Sequences for UAV Waypoint Flight Control

Expression and drought functional analysis of one circRNA PecircCDPK from moso bamboo (Phyllostachys edulis).

Drought stress can affect the growth of bamboo. Circle RNAs (CircRNAs) have been found to play a role in drought stress in plants, but their function in moso bamboo is not well understood. In previous studies, we observed that under drought stress, the expression of some circRNAs were altered and predicted to be involved in calcium-dependent protein kinase phosphorylation, as indicated by KEGG enrichment analysis. In this study, we cloned a circRNA called PecircCDPK in moso bamboo that is responsive to drought stress. To further investigate its function, we constructed an overexpression vector using flanking intron sequences supplemented by reverse complementary sequences. When this vector was transferred to Arabidopsis plants, we observed that the roots of the transgenic lines were more developed, the water loss rate decreased, the stomata became smaller, and the activity of antioxidant enzymes increased under drought stress. These findings suggest that overexpression of PecircCDPK can enhance the drought resistance of Arabidopsis thaliana, providing valuable insights for the breeding of moso bamboo with improved resistance to drought.

Small Molecule Detection with Ligation-Dependent Light-Up Aptamer Transcriptional Amplification.

ATP and NAD+ are small biomolecules that participate in a variety of physiological functions and are considered as potential biomarkers for disease diagnosis. In this study, we developed a ligation-dependent light-up aptamer transcriptional amplification assay for the sensitive and selective detection of ATP and NAD+. This assay relies on a specific DNA ligase that catalyzes the ligation of a nicked DNA template in the presence of a specific small molecule. We prepared a nicked template consisting of a duplex fragment with an overhang for the T7 promoter region and a single-stranded DNA with a complementary overhang sequence for the Broccoli aptamer. The nicked template was connected using a DNA ligase in the presence of a specific small molecule. The ligation product was subjected to in vitro transcription to amplify the light-up aptamer-mediated fluorescence signals. By integrating the target-dependent ligation and transcription amplification, significant signal amplification was achieved with 5.9 and 142 pM detection limits for ATP and NAD+, respectively. Moreover, good selectivity to discriminate between the target and its analogues was also realized. The application of this method to biological samples was evaluated using human serum and exhibited excellent recovery values.

Waveguide-Enhanced Nanoplasmonic Biosensor for Ultrasensitive and Rapid DNA Detection.

DNA is fundamental for storing and transmitting genetic information. Analyzing DNA or RNA base sequences enables the identification of genetic disorders, monitoring gene expression, and detecting pathogens. Traditional detection techniques like polymerase chain reaction (PCR) and next-generation sequencing (NGS) have limitations, including complexity, high cost, and the need for advanced computational skills. Therefore, there is a significant demand for enzyme-free and amplification-free strategies for rapid, low-cost, and sensitive DNA detection. DNA biosensors, especially those utilizing plasmonic nanomaterials, offer a promising solution. This study introduces a novel DNA-functionalized waveguide-enhanced nanoplasmonic optofluidic biosensor using a nanogold-linked sorbent assay for enzyme-free and amplification-free DNA detection. Integrating plasmonic gold nanoparticles (AuNPs) with a glass planar waveguide (WG) and a microfluidic channel, fabricated through cost-effective, vacuum-free methods, the biosensor achieves specific detection of complementary target DNA sequences. Utilizing a sandwich architecture, AuNPs labeled with detection DNA probes enhance sensitivity by altering evanescent wave distribution and inducing plasmon resonance modes. The biosensor demonstrated exceptional performance in DNA detection, achieving a limit of detection (LOD) of 33.1 fg/mL (4.36 fM) with a rapid response time of approximately 8 min. This ultrasensitive, rapid, and cost-effective biosensor exhibits minimal background nonspecific adsorption, making it highly suitable for clinical applications and early disease diagnosis. The innovative design and fabrication processes offer significant advantages for mass production, presenting a viable tool for precise disease diagnostics and improved clinical outcomes.

Single-stranded DNA regulated peroxidase mimetic activity of MCOF@AuNPs for colorimetric detection of carcinoembryonic antigen

Rapid, accurate, simple and portable monitoring of carcinoembryonic antigen (CEA) in serum is important for assessing the occurrence, development, and prognosis of cancer. In this work, we developed a colorimetric method based on the peroxidase-like activity of MCOF@AuNPs functionalized by complementary sequences of CEA-specific aptamer (MCOF@AuNPs-apt*) enhancing by G-terminated CEA-specific aptamer (G-apt). The enhancement of catalytic activity depends on the increase affinity of MCOF@AuNPs-apt*-G-apt to the TMB via promoting electron transfer. Based on this strategy, we successfully detected CEA at 0.1 ng/mL with high accuracy and anti-interference ability. Importantly, combined with the smartphone app based on the smartphone app RGB color model, the results can be visualized directly without expensive equipment, which meets the demand for point of care testing of CEA. This study also explored the enhancement of catalytic activity of nanozyme by ssDNA and the application potential in aptamer biosensor.

A new exploration of the amplification mechanism of saltatory rolling circle amplification (SRCA) for food safety detection

A new property of Bst DNA polymerase was discovered by our team, which led to the establishment of a new isothermal amplification method for SRCA nucleic acid, which was applied to food safety detection, investigated the amplification mechanism, and the SRCA version 1.0 amplification mechanism was proposed. This study proposes a new SRCA amplification mechanism (version 2.0) by using the autosynthetic sequences CDG2040 and CDG2068, as well as the Listeria monocytogenes hlyA gene and Vibrio parahaemolyticus toxR gene as target sequences to further investigate the amplification mechanism. The initiation of the SRCA reaction depends primarily on the spatial structure of the non-closed circle formed by the discontinuous complementation of the bases on both sides of the target sequence. The DNA fragments that connect the target sequences in the SRCA reaction are the sum of the complementary sequences of adjacent partial sequences on both sides of the target sequence.

Preparation of DNA nanoflower-modified capillary silica monoliths for chiral separation.

Innovative chiral capillary silica monoliths (CSMs) were developed based on DNA nanoflowers (DNFs). Baseline separation of enantiomers such as atenolol, tyrosine, histidine, and nefopam was achieved by using DNF-modified CSMs, and the obtained resolution value was higher than 1.78. To further explore the effect of DNFs on enantioseparation, different types of chiral columns including DNA strand containing the complementary sequence of the template (DCT)-modified CSMs, DNF2-modified CSMs, and DNF3-modified CSMs were prepared as well. It was observed that DNF-modified CSMs displayed better chiral separation ability compared with DCT-based columns. The intra-day and inter-day repeatability of model analytes' retention time and resolution kept desirable relative standard deviation values of less than 8.28%. DNF2/DNF3-modified CSMs were able to achieve baseline separation of atenolol, propranolol, 2'-deoxyadenosine, and nefopam enantiomers. Molecular docking simulations were performed to investigate enantioselectivity mechanisms of DNA sequences for enantiomers. To indicate the successful construction of DNFs and DNF-modified CSMs, various charaterization approaches including scanning electron microscopy, agarose gel electrophoresis, dynamic light scattering analysis, electroosmotic flow, and Fourier-transform infrared spectroscopy were utilized. Moreover, the enantioseparation performance of DNF-modified CSMs was characterized in terms of sample volume, applied voltage, and buffer concentration. This work paves the way to applying DNF-based capillary electrochromatography microsystems for chiral separation.

Diverse Head-to-Tail Sequences in the Circular Genome of Human Bocavirus Genotype 1 among Children with Acute Respiratory Infections Implied the Switch of Template Chain in the Rolling-Circle Replication Model.

Head-to-tail sequences have been reported in human bocavirus (HBoV) 1-4. To reveal their features and functions, HBoV DNA was screened among respiratory specimens from pediatric patients with an acute respiratory infection (ARI) between April 2020 and December 2022, followed by HBoV genotyping. Head-to-tail sequences were detected using nested PCR, TA cloning, and Sanger sequencing, and these findings were confirmed by mNGS and amplicon sequencing. The secondary structure was predicted using the Mfold web server. The results indicated that head-to-tail sequences were detected in 42 specimens through TA cloning from 351 specimens positive for HBoV1 DNA, yielding 92 sequences into 32 types and 2 categories. Additionally, head-to-tail sequences were detected in 16 specimens by amplicon sequencing, yielding 60 sequences categorized into 23 types. The 374nt type, detected in 13 specimens, contains variants 374a and 374b, which differ in the unpaired loop regions of the palindrome or complementary reverse sequences, implying a switch of template chains during the replication process. The mNGS results in three specimens confirmed the presence of circular genome in copies below 1%. In conclusion, head-to-tail sequences of HBoV1 were common in children with ARI and were highly diverse in length and sequences. The variants may be generated by the switch of the template chain in the rolling-circle replication model.

Investigation of Introns in Proteus Mirabilis Bacteria and Extent of their Resistance to Antibiotics

Proteus mirabilis is an opportunistic pathogen meaning that causes infection in people with reduced natural immunity. These bacteria possess many virulence factors or pathogens which is essential for colonizing new areas, including tissues and hosts. The study aimed to investigate phenotypically or genetically the introns (MIs) in P. mirabilis by estimate the extent of its resistance to antibiotics. The results showed that the appearance of genetic packages for all migrated isolates at one level. This is an indication of the binding of the primer to its complementary sequence in the DNA strand. The molecular weights of the resulting genetic packages were estimated based on known standard packages, the apparent molecular weights in the path (M) with a graduated size (100- 200 bp). The results also showed a clear similarity of the molecular weight of the resulting bands (1500 bp) with the molecular weight of the diagnostic gene rRNA 16s. In addition, 20 isolates were examined using PCR technology for the three classes of introns gene. All isolates were carried the chromosome intron gene. The appearance of the intron 1 gene on all isolates was (100%).