Pcr Assay
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2022 ◽  
Author(s):  
Hannah Hussey ◽  
Mary-Ann Davies ◽  
Alexa Heekes ◽  
Carolyn Williamson ◽  
Ziyaad Valley-Omar ◽  
...  

Background Emerging data suggest that SARS-CoV-2 Omicron variant of concern (VOC)is associated with reduced risk of severe disease. The extent to which this reflects a difference in the inherent virulence of Omicron, or just higher levels of population immunity, is currently not clear. Methods RdRp target delay (RTD: a difference in cycle threshold value of RdRp - E > 3.5) in the Seegene AllplexTM 2019-nCoV PCR assay is a proxy marker for the Delta VOC. The absence of this proxy marker in the transition period was used to identify suspected Omicron VOC infections. Cox regression was performed for the outcome of hospital admission in those who tested positive for SARS-CoV-2 on the Seegene AllplexTM assay from 1 November to 14 December 2021 in the Western Cape Province, South Africa, public sector. Vaccination status at time of diagnosis, as well as prior diagnosed infection and comorbidities, were adjusted for. Results 150 cases with RTD (proxy for Delta) and 1486 cases without RTD (proxy for Omicron) were included. Cases without RTD had a lower hazard of admission (adjusted Hazard Ratio [aHR] of 0.56, 95% confidence interval [CI] 0.34-0.91). Complete vaccination was protective of admission with an aHR of 0.45 (95%CI 0.26-0.77). Conclusion Omicron has resulted in a lower risk of hospital admission, compared to contemporaneous Delta infection in the Western Cape Province, when using the proxy marker of RTD. Under-ascertainment of reinfections with an immune escape variant like Omicron remains a challenge to accurately assessing variant virulence.


Author(s):  
Le Thi Thanh Nhan ◽  
Nguyen Thuy Quynh ◽  
Le Lan Phuong ◽  
Bui Phuong Thao ◽  
Nguyen Thi Tu Linh ◽  
...  

For the prevalence of lung cancer and its poor diagnosis, the seeking of the efficient biomarkers for this disease is an urgent requirement, especially from non-invasive samples such as plasma. The mitochondria DNA (mtDNA) copy number change has been evaluated as a potential indicator of cancer risk, however, there have been few studies regarding mtDNA in plasma derived exosomes. In this study, the mtDNA copy number was measured on 29 plasma exosome samples of patients with non-small cell lung cancer (NSCLC) and 29 plasma exosome samples of cancer-free controls by real-time PCR assay, then being statistically analyzed to evaluate the relationship between these figures and several pathological features of NSCLC patients. As the results, the existence of mtDNA in exosomes isolated from plasma was detected through PCR assay using primers covering most of the mtDNA length. The relative mtDNA copy numbers determined in the exosomes of the disease and control groups were 1619.1 ± 2589.0 and 1207.0 ± 1550.0, respectively, whereas these values in two disease stages were 783.6 ± 759.3 (stage I-II) and 2647.0 ± 3584.0 (stage III-IV). Comparing among these groups, the difference was only statistically significant between the disease groups of stage I-II and stage III-IV (p<0.05), the group of stage III-IV and the control group (p<0.05). Indeed, the mtDNA copy number is associated with tumor stage and stage N (p<0.05). On the other aspect, the smoking habit of NSCLC patients could be an underlying reason behind the alteration in mtDNA copy number in the plasma exosomes. In short, our study demonstrates that the mtDNA copy number in exosomes resourced from plasma could be a potential biomarker for the detection and prognosis of NSCLC.


Author(s):  
R. Jyothi Priya ◽  
Ganne Venkata Sudhakar Rao ◽  
N. Pazhanivel ◽  
K. Vijayarani ◽  
T. Lurthu Reetha ◽  
...  

Background: Infectious laryngotracheitis (ILT) is an economically important viral respiratory disease in poultry. Recently, re-emergence of Infectious laryngotracheitis virus (ILTV) has been reported in several countries including India. The current study aimed to evaluate the poultry flocks of Tamil Nadu with circulating GaHV-1 and to elucidate the origin of the virus involved in the outbreak. Methods: In this study, a molecular based survey on the overall occurrence of natural cases of Infectious laryngo-tracheitis in poultry flocks from Tamil Nadu, India were performed. Pathological findings in respiratory and secondary lymphoid organs like caecal tonsils and harderian gland was carried out. The PCR technique targeting Infected Cell Protein-4 (ICP4) gene along with molecular characterization was performed. Result: The overall prevalence rate in the outbreak was 42.86% with highest incidence in layer flocks (62.85%) than the broiler flocks (22.85%). The highest susceptible age groups were between 20-30 weeks old. Tracheal pathology revealed epithelial sloughing, syncytial cell formation, eosinophilic intranuclear inclusion bodies and heterophilic exudation microscopically. Partial genome sequencing and phylogenetic analysis of ICP4 gene revealed high genetic homology between field isolates and the virulent strains from Turkey, Germany, China and Brazil. In the present study, along with pathological findings, a rapid and sensitive PCR assay was used for detection of ILT virus specific ICP4 gene in commercial poultry farms in the region.


2022 ◽  
Author(s):  
Justin Clements ◽  
Maggie Haylett ◽  
Brenda Nelson ◽  
Silas Shumate ◽  
Nicole Young ◽  
...  

The alfalfa leafcutting bee Megachile rotundata Fabricius (HYMENOPTERA: Megachilidae) is an important pollinator for multiple agricultural seed commodities in the United States. Megachile rotundata is a solitary bee that forms brood cocoons where its larvae can develop. During the developmental stages of growth, broods can be preyed upon by multiple different fungal and bacterial pathogens and insect predators and parasitoids, resulting in the loss of the developing larvae. Larval loss is a major concern for alfalfa (Medicago sativa L.) seed producers because they rely on pollinator services provided by Megachile rotundata and reduced pollination rates result in lower yields and increased production costs. In the present study, we examined the taxonomic composition of organisms found within M. rotundata brood cells using a multiplex PCR assay which was developed for the detection of the most common bacterial, fungal, and invertebrate pests and pathogens of M. rotundata larvae. Known pests of M. rotundata were detected, including members of the fungal genus Ascosphaera, the causative agent of chalkbrood. Co-infection of single brood cells by multiple Ascosphaera species was confirmed, with potential implications for chalkbrood disease management. The multiplex assay also identified DNA from more than 2,400 total species including multiple new predators and pathogenetic species not previously documented in associated with M. rotundata brood cells.


2022 ◽  
Vol 12 ◽  
Author(s):  
Susana Ruiz-Ruiz ◽  
Carolina A. Ponce ◽  
Nicole Pesantes ◽  
Rebeca Bustamante ◽  
Gianna Gatti ◽  
...  

Here we report a new real-time PCR assay using SYBR Green which provides higher sensitivity for the specific detection of low levels of Pneumocystis jirovecii. To do so, two primer sets were designed, targeting the family of genes that code for the most abundant surface protein of Pneumocystis spp., namely the major surface glycoproteins (Msg), and the mitochondrial large subunit rRNA (mtLSUrRNA) multicopy gene, simultaneously detecting two regions. PCR methods are instrumental in detecting these low levels; however, current nested-PCR methods are time-consuming and complex. To validate our new real-time Msg-A/mtLSUrRNA PCR protocol, we compared it with nested-PCR based on the detection of Pneumocystis mitochondrial large subunit rRNA (mtLSUrRNA), one of the main targets used to detect this pathogen. All samples identified as positive by the nested-PCR method were found positive using our new real-time PCR protocol, which also detected P. jirovecii in three nasal aspirate samples that were negative for both rounds of nested-PCR. Furthermore, we read both rounds of the nested-PCR results for comparison and found that some samples with no PCR amplification, or with a feeble band in the first round, correlated with higher Ct values in our real-time Msg-A/mtLSUrRNA PCR. This finding demonstrates the ability of this new single-round protocol to detect low Pneumocystis levels. This new assay provides a valuable alternative for P. jirovecii detection, as it is both rapid and sensitive.


2022 ◽  
Vol 20 (6) ◽  
pp. 41-54
Author(s):  
N. A. Smetannikova ◽  
M. A. Abdurashitov ◽  
A. G. Akishev ◽  
P. I. Pozdnyakov ◽  
E. V. Dubinin ◽  
...  

Hypermethylation of the RcgY sites is shown for many cancer diseases. such aberrant methylation, suppressing the gene activity, occurs at early stages of carcinogenesis. Recently, using glad-pcR assay, we have detected aberrantly methylated RcgY sites, which can be considered to be epigenetic markers of colorectal, lung, and gastric cancers. in breast cancer, methylation of the regulatory regions of ALX4, BMP2, CCND2, CDH13, CDX1, FOXA1, GALR1, GATA5, GREM1, HIC1, HMX2, HS3ST2, HOXC10, ICAM5, LAMA1, RARB, RASSF1A, RUNX3, RXRG, RYR2, SFRP2, SOX17, TERT, and ZNF613 tumor-suppressor genes is reported. in the present work, we determined aberrantly methylated RcgY sites in the regulatory regions of these genes in dNa preparations from breast cancer tissues. the study of dNa samples from 30 tumor and 22 normal mammary tissue samples demonstrates a high diagnostic potential of selected R(5mc)gY sites in regulatory regions of CCND2, BMP2, GALR1, SOX17, HMX2, and HS3ST2 genes with total index of sensitivity and specificity for R(5mc)gY detection in tumor dNa 90.0 % and 100.0 %, respectively.


Diagnostics ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 147
Author(s):  
Sergei A. Kiryanov ◽  
Tatiana A. Levina ◽  
Maria V. Konopleva ◽  
Anatoly P. Suslov

Sensitive and reliable diagnostic test systems based on real-time PCR are of great importance in the fight against the ongoing SARS-CoV-2 pandemic. The genetic variability of the SARS-CoV-2 virus leads to the accumulation of mutations, some of which may affect the sensitivity of modern PCR assays. The aim of this study was to search in Russian clinical samples for new mutations in SARS-CoV-2 gene N that can affect the detection by RT-PCR. In this study, the polymorphisms in the regions of the target gene N causing failed or poor detection of the target N in the RT-PCR assay on 12 selected samples were detected. Sequencing the entire N and E genes in these samples along with other 195 samples that were positive for both target regions was performed. Here, we identified a number of nonsynonymous mutations and one novel deletion in the N gene that affected the ability to detect a target in the N gene as well a few mutations in the E gene of SARS-CoV-2 that did not affect detection. Sequencing revealed that majority of the mutations in the N gene were located in the variable region between positions 193 and 235 aa, inside and nearby the phosphorylated serine-rich region of the protein N. This study highlights the importance of the further characterization of the genetic variability and evolution of gene N, the most common target for detecting SARS-CoV-2. The use of at least two targets for detecting SARS-CoV-2, including one for the E gene, will be necessary for reliable diagnostics.


Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 208
Author(s):  
Gaurav Kumar ◽  
Jacqueline Cottalorda-Dufayard ◽  
Rodolphe Garraffo ◽  
Francine De Salvador-Guillouët ◽  
Eric Cua ◽  
...  

Raltegravir (RLT) prevents the integration of HIV DNA in the nucleus, but published studies remain controversial, suggesting that it does not decrease proviral DNA. However, there are only a few studies focused on virus-targeted cells. We aimed our study on the impact of RLT inclusion on total intra-cellular viral DNA (TID) in cellular subsets and immune effects in patients with newly acquired undetectable plasmatic viral load (UVL). Six patients having UVL using an antiretroviral combination for 6 months and CD4 T-cells > 350/mL and <500/mL were selected to receive RLT for 3 months from M0 to M3. Patients had 7 sequential viro-immunological determinations from M-1 to M5. Immune phenotypes were determined by flow cytometry and TID quantification was performed using PCR assay on purified cells. TID (median values) at the initiation of RLT in CD4 T-cells was 117 copies/millions of cells, decreased to 27.5 on M3, and remained thereafter permanently under the cut-off (<10 copies/millions of cells) in 4 out of 6 patients. This was associated with an increase of CD4 and CD4 + CD28+ T-cells and a decrease of HLA-DR expression and apoptosis of CD4 T-cells. RLT inclusion led to decreases in the viral load along with positive immune reconstitution, mainly for CD4 T-cells in HIV patients.


2022 ◽  
Author(s):  
Vemula Harshini ◽  
S.M.K. Karthickeyan ◽  
K.G P. Kumarasamy ◽  
Tirumurugaan ◽  
C. Jeevan

Abstract A SYBR green real-time PCR assay was developed to find out the sex skewness in bovine sex-sorted semen samples. The qPCR assay of PLP and SRY genes revealed the mean values of X- and Y-bearing spermatozoa as 50.24 ± 0.65 and 49.75 ± 0.62 per cent in unsorted, and 91.80 ± 0.79 and 8.20 ± 0.73 per cent in X-enriched semen samples respectively.. The amplification efficiencies of the PLP and SRY primers were 99.25 and 98.03 per cent respectively. The method was validated by a series of repeatability and reproducibility assays which revealed low co-efficients of variations as 2.19 and 3.12 per cent respectively Thus becoming a reliable and inexpensive tool to evaluate the sorted semen on routine basis and validation of other sperm sexing technologies.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Subeen Hong ◽  
Seung Mi Lee ◽  
Sohee Oh ◽  
So Yeon Kim ◽  
Young Mi Jung ◽  
...  

AbstractTo examine the detection performance of a peptide nucleic acid (PNA) probe-based real-time time polymerase chain reaction (PCR) assay to detect common aneuploidies. Using amniotic fluid samples, PNA probe based real-time PCR (Patio DEP Detection Kit; SeaSun Biomaterials, Korea) assay was performed. PNA probe was designed to hybridize to similar sequences located on different segments of target chromosomes (21, 18, and 13) and a reference chromosome. Amplification of target sequences and melting curve analysis was performed. When analyzing the melting curve, the ratio of the peak height of the target and reference chromosome was calculated and determined as aneuploidy if the ratio of peak height was abnormal. All the results from the PNA probe-based real-time PCR and melting curve analyses were compared to those from conventional karyotyping. Forty-two cases with common aneuploidies (24 of trisomy 21, 12 of trisomy 18, and 6 of trisomy 13) and 131 cases with normal karyotype were analyzed. When comparing the karyotyping results, the sensitivity and specificity of the PNA probe-based real-time PCR assay were both 100%. The level of agreement was almost perfect (k = 1.00). PNA real-time PCR assay is a rapid and easy method for detecting common aneuploidies.


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