M gene targeted qRT-PCR approach for SARS-CoV-2 virus detection.

Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) is the gold standard method for SARS-CoV-2 detection, and several qRT-PCR kits have been established targeting different genes of the virus. Due to the high mutation rate of these genes, false negative results arise thus complicating the interpretation of the diagnosis and increasing the need of alternative targets. In this study, an alternative approach for the detection of SARS-CoV-2 viral RNA targeting the membrane (M) gene of the virus using qRT-PCR was described. Performance evaluation of this newly developed in-house assay against commercial qRT-PCR kits was done using clinical oropharyngeal specimens of COVID-19 positive patients. The limit of detection was determined using successive dilutions of known copies of SARS-CoV-2 pseudovirus. The M gene based assay was able to detect a minimum of 100 copies of virus/mL indicating its capacity to detect low viral load. The assay showed comparable accuracy, sensitivity and specificity with commercially available kits while detecting all the variants efficiently. The study concluded that the in-house M gene based assay might be an effective alternative for the currently available commercial qRT-PCR kits.

Miliary tuberculosis in an immune-competent Bangladeshi man-A case report.

Miliary tuberculosis is a disseminated and active form of tuberculosis caused by Mycobacterium tuberculosis. It frequently affects immunocompromised patients. However, immune-competent hosts are reported rarely. Herein, we reported a case of miliary tuberculosis of a 40-year-old immune-competent Bangladeshi man presented with pyrexia of unknown origin.

Respiratory symptoms, spirometric, and radiological status of stone-cutting workers in Bangladesh: A cross-sectional study.

Background and Aims: Inhalation of respirable silica dust during several stone processing methods can result in several respiratory diseases. However, data are scarce regarding the respiratory health of stone-cutting workers in Bangladesh. We aimed to determine the point prevalence of respiratory symptoms, lung function status and radiological abnormalities among the stone-cutting workers. Methods: This cross-sectional study was conducted among 200 stone-cutting workers. Adult workers having a job experience of at least 3 years participated in this study. Then inquiry was made regarding respiratory symptoms with the help of a preformed questionnaire. All the participants underwent chest X-ray and spirometry. A respiratory dust sampler was used to measure the dust concentration of the stone-cutting factories. Results: Among the 200 stone-cutting workers, 89% (178) showed at least one chronic respiratory symptom while they had chest tightness (75.5%), chronic cough (74.5%), and shortness of breath (66.5%) as the most prominent ones. Spirometry findings revealed that the mean forced expiratory volume in 1 s (FEV1) value was 1.42± 0.65 L in the obstructive pattern, 1.43 ± 0.73 L in the restrictive pattern. The mean forced vital capacity (FVC) value was 2.53 ± 1.12 L in the obstructive pattern, 1.53 ± 0.75 L in the restrictive pattern. 42.69% of stone-cutting workers who complained of at least one respiratory symptom had abnormal chest X-ray findings. Those with progressive massive fibrosis had the lowest mean FEV1 value (0.75 ± 0.50 L). While measuring workplace dust concentration, we found high particulate matter (PM) 2.5 (979.78 µg/m3) and PM 10 (1298.35 µg/m3) values. Conclusions: Most of the stone-cutting workers in our study exhibited different respiratory symptoms. These symptoms were associated with abnormal lung function and radiology. Further longitudinal studies are recommended to determine the actual dimension of this problem.

Expression of root-related transcription factors associated with flooding tolerance of soybean (Glycine max).

Much research has been conducted on the changes in gene expression of the model plant Arabidopsis to low-oxygen stress. Flooding results in a low oxygen environment in the root zone. However, there is ample evidence that tolerance to soil flooding is more than tolerance to low oxygen alone. In this study, we investigated the physiological response and differential expression of root-related transcription factors (TFs) associated with the tolerance of soybean plants to soil flooding. Differential responses of PI408105A and S99-2281 plants to ten days of soil flooding were evaluated at physiological, morphological and anatomical levels. Gene expression underlying the tolerance response was investigated using qRT-PCR of root-related TFs, known anaerobic genes, and housekeeping genes. Biomass of flood-sensitive S99-2281 roots remained unchanged during the entire 10 days of flooding. Flood-tolerant PI408105A plants exhibited recovery of root growth after 3 days of flooding. Flooding induced the development of aerenchyma and adventitious roots more rapidly in the flood-tolerant than the flood-sensitive genotype. Roots of tolerant plants also contained more ATP than roots of sensitive plants at the 7th and 10th days of flooding. Quantitative transcript analysis identified 132 genes differentially expressed between the two genotypes at one or more time points of flooding. Expression of genes related to the ethylene biosynthesis pathway and formation of adventitious roots was induced earlier and to higher levels in roots of the flood-tolerant genotype. Three potential flood-tolerance TFs which were differentially expressed between the two genotypes during the entire 10-day flooding duration were identified. This study confirmed the expression of anaerobic genes in response to soil flooding. Additionally, the differential expression of TFs associated with soil flooding tolerance was not qualitative but quantitative and temporal. Functional analyses of these genes will be necessary to reveal their potential to enhance flooding tolerance of soybean cultivars.