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Xiao D, Hu C, Xu X, Lü C, Wang Q, Zhang W, Gao C, Xu P, Wang X, Ma C. A d,l-lactate biosensor based on allosteric transcription factor LldR and amplified luminescent proximity homogeneous assay. Biosens Bioelectron 2022; 211:114378. [PMID: 35617798 DOI: 10.1016/j.bios.2022.114378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 05/11/2022] [Accepted: 05/13/2022] [Indexed: 11/02/2022]
Abstract
Lactate, a hydroxycarboxylic acid commercially produced by microbial fermentation, is widely applied in diverse industrial fields. Lactate exists in two stereoisomeric forms (d-lactate and l-lactate). d-Lactate and l-lactate are often simultaneously present in many biological samples. Therefore, a biosensor able to detect both d- and l-lactate is required but previously unavailable. Herein, an allosteric transcription factor LldR from Pseudomonas aeruginosa PAO1, which responds to both d-lactate and l-lactate, was combined with amplified luminescent proximity homogeneous assay technology to develop a d,l-lactate biosensor. The proposed biosensor was optimized by mutation of DNA sequence in binding site of LldR. The optimized biosensor BLac-6 can accurately detect the concentration of lactate independent on ratio of the two isomers in pending test samples. The biosensor was also tentatively used in quantitative analysis of d-lactate, l-lactate, or d,l-lactate in fermentation samples produced by three recombinant strains of Klebsiella oxytoca. With its desirable properties, the biosensor BLac-6 may be a potential choice for monitoring the concentration of lactate during industrial fermentation.
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Affiliation(s)
- Dan Xiao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Chunxia Hu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Xianzhi Xu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Chuanjuan Lü
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Qian Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Wen Zhang
- Institute of Medical Sciences, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250033, PR China
| | - Chao Gao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China
| | - Xia Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China
| | - Cuiqing Ma
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China.
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Porta G, Numis FG, Rosato V, Pagano A, Masarone M, Bosso G, Serra C, Rinaldi L, Fascione MC, Amelia A, Paladino F, Schiraldi F. Lactate determination in pleural and abdominal effusions: a quick diagnostic marker of exudate-a pilot study. Intern Emerg Med 2018; 13:901-906. [PMID: 28965174 DOI: 10.1007/s11739-017-1757-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
Abstract
Pleural or abdominal effusions are frequent findings in ICU and Internal Medicine patients. Diagnostic gold standard to distinguish between transudate and exudate is represented by "Light's Criteria," but, unfortunately, the chemical-physical examination for their calculation is not a rapid test. Pursuing an acid-base assessment of the fluid by a blood-gas analyzer, an increase of lactate beyond the normal serum range is reported in the exudative effusions. The advantages of this test are that it is a very fast bed-side test, executable directly by the physician. The aim of this study is to evaluate whether the increase in lactate in pleural and abdominal effusions might be used as a criterion for the differential diagnosis of the nature of the fluid. Sixty-nine patients with pleural or abdominal effusions and clinical indication for thoracentesis or paracentesis were enrolled. Acid-base assessment with lactate, total protein, and LDH dosage on the serum, and acid-base assessment with lactate, total protein, and LDH dosage, cytology, and bacterial culture on the fluid were performed to each patient. Fluid-blood lactate difference (ΔLacFB) and fluid-blood lactate ratio (LacFB ratio) were calculated. A statistical analysis was carried out for fluid lactate (LacF), ΔLacFB, and LacFB ratio, performing ROC curves to find the cut-off values with best sensitivity (Sn) and specificity (Sp) predicting an exudate diagnosis: LacF: cut-off value: 2.4 mmol/L; AU-ROC 0.854 95% CI 0.756-0.952; Sn 0.77; Sp 0.84. ΔLacFB: cut-off value: 0.95 mmol/L; Au-ROC 0.876 95% CI 0.785-0.966; Sn 0.80; Sp 0.92. LacFB ratio: cut-off value: 2 mmol/L; Au-ROC 0.730 95% CI 0.609-0.851; Sn 0.74; Sp 0.65. Lactate dosage by blood-gas analyzer on pleural and abdominal effusions seems to be a promising tool to predict a diagnosis of exudate.
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Affiliation(s)
- Giovanni Porta
- Emergency Department, "A. Cardarelli" Hospital, Via Cardarelli 9, 80131, Naples, Italy.
| | - Fabio G Numis
- Emergency Department, "San Paolo" Hospital, Naples, Italy
| | - Valerio Rosato
- Internal Medicine and Hepatology Department, Second University of Naples, Naples, Italy
| | - Antonio Pagano
- Emergency Department, "A. Cardarelli" Hospital, Via Cardarelli 9, 80131, Naples, Italy
| | - Mario Masarone
- Internal Medicine and Hepatology Unit, University of Salerno, Baronissi, Italy
| | - Giorgio Bosso
- Emergency Department, "A. Cardarelli" Hospital, Via Cardarelli 9, 80131, Naples, Italy
| | - Claudia Serra
- Emergency Department, "A. Cardarelli" Hospital, Via Cardarelli 9, 80131, Naples, Italy
| | - Luca Rinaldi
- Internal Medicine and Hepatology Department, Second University of Naples, Naples, Italy
| | - Maria C Fascione
- Internal Medicine and Hepatology Department, Second University of Naples, Naples, Italy
| | - Annalisa Amelia
- Internal Medicine and Hepatology Department, Second University of Naples, Naples, Italy
| | - Fiorella Paladino
- Emergency Department, "A. Cardarelli" Hospital, Via Cardarelli 9, 80131, Naples, Italy
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