Key determinants of misdiagnosis of tracheobronchial tuberculosis among senile patients in contemporary clinical practice: A retrospective analysis.

BACKGROUND: Tracheobronchial tuberculosis (TBTB) is a common subtype of pulmonary tuberculosis. Concomitant diseases often obscure the diagnosis of senile TBTB. AIM: To characterize senile patients with TBTB and to identify the potential causes of misdiagnosis. METHODS: One hundred twenty patients with senile TBTB who were admitted to the Anhui Chest hospital between May 2017 and May 2019 were retrospectively analyzed. Patients were classified as diagnosed group (n = 58) and misdiagnosed group (n = 62). Clinical manifestations, laboratory results, radiographic data, and endoscopic findings were compared between the two groups. RESULTS: Patients in the misdiagnosed group were most commonly diagnosed as pulmonary tuberculosis (non-TBTB, 29/62, 46.8%), general pneumonia (9/62, 14.5%), chronic obstructive pulmonary disease (8/62, 12.9%), and tracheobronchial carcinoma (7/62, 11.3%). The time elapsed between disease onset and confirmation of diagnosis was significantly longer in the misdiagnosed group [median (first quartile, third quartile): 6.32 (4.94, 16.02) mo vs 3.73 (2.37, 8.52) mo]. The misdiagnosed group had lower proportion of patients who underwent bronchoscopy [33.87% (21/62) vs 87.93% (51/58)], chest computed tomography (CT) scan [69.35% (43/62) vs 98.28% (57/58)], and those who showed CT signs of tuberculosis [27.91% (12/62) vs 50% (29/58)] as compared to that in the diagnosed group (P < 0.05). There were no significant between-group differences with respect to age, gender, occupation, clinical manifestations, or prevalence of comorbid chronic diseases (P > 0.05). CONCLUSION: Insufficient or inaccurate radiographic or bronchoscopic assessment was the predominant cause of delayed diagnosis of TBTB. Increased implementation and better interpretation of CT scan and early implementation of bronchoscopy can help reduce misdiagnosis of senile TBTB.

Effects of submerged liquid fermentation of Bacillus subtilis WX-17 using okara as sole nutrient source on the composition of a potential probiotic beverage.

This work aims to produce a functional probiotic beverage using okara as the sole nutrient source. Hence, okara was fermented with Bacillus subtilis WX-17 in submerged liquid fermentation and the supernatant was tested. Metabolomic analysis showed that the nutritional profile of the beverage was enhanced after fermentation. Essential amino acids as well as short-chain fatty acids were significantly (p < .05) upregulated. Total phenolic content and antioxidant content (in terms of DPPH radical scavenging activity) increased by 6.32 and 1.55 times, respectively. After 6 weeks, probiotic viability remains unchanged when stored at 4°C and the cell count is above the minimum dosage to confer health benefits. Antimicrobial activity was also detected against gram-positive bacteria. The findings of this work showed the potential of submerged liquid fermentation of Bacillus subtilis WX-17 using okara as sole substrate to produce a functional and low-cost probiotic beverage.

Increasing L-homoserine production in Escherichia coli by engineering the central metabolic pathways.

l-homoserine is an important functional amino acid. Based on the system metabolic engineering strategy, the key genes in the central metabolic pathway of Escherichia coli W3110 were engineered to construct the strain for l-homoserine production. To construct an engineered strain with high yield of l-homoserine, the work was carried out from the following aspects: (1) Disrupt the competitive and degradative pathways of l-homoserine, and the l-homoserine was initially accumulated with a titer of 0.2 g/L; (2) Exploring the effect of weakening TCA cycle, modification of the glyoxylate branch, and reduction of the pyruvate synthesis for l-homoserine synthesis. The concentration of l-homoserine in the final recombinant strain LJL12 reached a titer of 3.2 g/L at shake flask and 35.8 g/L in fed-batch fermentation, showing a high l-homoserine production capacity (0.82 g/L/h). The study provides a well research foundation for l-homoserine production with the capacity for industrial application.

CRISPR/Cpf1 facilitated large fragment deletion in Saccharomyces cerevisiae.

In this study, we focused on the applicability of CRISPR/Cpf1 in genome simplification of Saccharomyces cerevisiae and established a CRISPR/Cpf1 assisted method for rapid markerless large fragment deletion to facilitate laboratory evolution of geome of S. cerevisiae by rational genetic engineering. This method uses a Cpf1 expression plasmid and a crRNA array expression plasmid. The DNA fragment between two DSBs generated by CRISPR/Cpf1 can be cut off from the chromosome, along with re-ligation of the genomic endpoints of the DSBs. Using this method, the large DNA fragment of ∼38 kb between the two genes of TRM10 and REX4 was successfully and rapidly deleted, which was verified by PCR and Sanger DNA Sequencing. This method is simple and rapid, and can be easily implemented for large fragment deletion in S. cerevisiae.

Metabolomics analysis of Pseudomonas chlororaphis JK12 algicidal activity under aerobic and micro-aerobic culture condition.

Utilization of algicidal bacteria as a biological agent have been receiving significant interest for controlling harmful algal blooms. While various algicidal bacterial strains have been identified, limited studies have explored the influence of bacterial culture conditions on its algicidal activity. Here, the effect of oxygen on the algicidal activity of a novel bacterium JK12, against a model diatom, Phaeodactylum tricornutum (P. tricornutum) was studied. Strain JK12 showed high algicidal activity against P. tricornutum and was identified as Pseudomonas chlororaphis (P. chlororaphis) by 16S ribosomal RNA gene analysis. JK12 culture supernatant exhibited strong algicidal activity while washed JK12 cells showed no obvious activity, indicating that JK12 indirectly attacks algae by secreting extracellular algicidal metabolites. Micro-aerobic culture condition dramatically enhanced the algicidal activity of JK12 by 50%, compared to that cultured under aerobic condition in 24 h. Extracellular metabolomic profiling of JK12 using gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry analysis revealed significantly higher amounts of allantoic acid, urocanic acid, cytidine 2',3'-cyclic phosphate, uridine 2',3'-cyclic phosphate, and chlorinated tryptophan in the micro-aerobic culture. This is the first report to demonstrate the important role of oxygen on the algicidal activity of a non-pathogenic strain P. chlororaphis. In addition, the metabolomics analysis provided insights into the algicidal mechanism of P. chlororaphis.