[Spectral CT multi-parameter imaging in preoperatively evaluation the status of lymphovascular and perineural invasion of gastric cancer].

Objective: To explore the application value of spectral CT multi-parameter imaging in preoperative assessment the status of lymphovascular invasion (LVI) and perineural invasion (PNI) in patients with gastric cancer. Methods: A total of 62 patients who underwent energy spectral CT and with pathology confirmed gastric cancer in Lanzhou Uiversity Second Hospital from September 2020 to September 2021 were retrospectively collected, which including 46 males and 16 females, aged from 36 to 71 (57.5±9.1) years. According to the presence or absence of LVI/PNI in postoperative pathological results, they were divided into the positive group (42 cases) and the negative group (20 cases). The CT values of 40 keV and 70 keV (CT40 keV, CT70 keV), iodine concentration (IC), normalized iodine concentration (NIC) were measured in the arterial phase, the venous phase, and the delay phase, and the spectral curve slope of 40 keV to 70 keV (K(40-70)) and the combined parameters (the arterial phase: AP~all, the venous phase: VP~all, the delay phase: DP~all) were calculated. Spectral parameters between the positive and negative groups were compared, and the receiver operating characteristic curve (ROC) with the area under the curve (AUC), sensitivity, specificity, and optimal threshold were calculated for evaluating the diagnostic performance of each parameter. Results: The CT40 keV, CT70 keV, K(40-70), IC, and NIC in the arterial phase and the venous phase and the CT70 keV and NIC in the delay phase of the LVI/PNI-positive group were all higher than those of the negative group [the representative parameters: the arterial phase NIC 0.14±0.04 vs 0.12±0.04, the venous phase NIC 0.5(0.5, 0.6) vs 0.4(0.4, 0.5), the delay phase NIC 0.6±0.1 vs 0.5±0.1, all P<0.05]. ROC curve analysis showed that the diagnostic efficacy of the parameters of the venous phase is better than that of the arterial phase and the delay phase, and the diagnostic efficiency of the combined parameters is better than that of the individual parameters. The AUC value, sensitivity, and specificity of the most optimal parameter VP~all of the venous phase were 0.931(95%CI:0.872-0.990), 80.95%, and 95.00%, respectively. Conclusions: In the preoperative evaluation the status of the LVI and PNI in gastric cancer, the diagnostic efficacy in the venous phase parameters is better than that in the arterial phase and delay phase, and the diagnostic efficacy of combined parameters is better than that of individual parameters.

High-yield strain of fusidic acid obtained by atmospheric and room temperature plasma mutagenesis and the transcriptional changes involved in improving its production in fungus Fusidium coccineum.

AIMS: To obtain the high-yield strain of fusidic acid, which is produced from fungus Fusidium coccineum and is the only fusidane-type antibiotic that has been used clinically, and confirm the changes in the transcription levels involved in increasing its production. METHODS AND RESULTS: By using the atmospheric and room temperature plasma mutagenesis technology, a high-yield mutant strain of fusidic acid-producing fungus F. coccineum was obtained. Using the genomic analysis of the original strain based on biosynthetic pathways of ergosterol and helvolic acid, we demonstrate that the pathway involved in the biosynthesis of 2,3-oxidosqualene from acetyl coenzyme A was shared by fusidic acid and ergosterol, and fusidic acid was finally synthesized by the catalysis of multiple cytochrome P450s and short-chain dehydrogenase/reductase from 2,3-oxidosqualene. Then, through the transcriptomic analysis of the original and mutagenized strain, it revealed that the proposed pathway from sucrose to fusidic acid was the most significantly up-regulated in the transcription levels of the mutant strain. CONCLUSIONS: The changes in the transcription levels of fusidic acid during its biosynthesis might result in high-yield of fusidic acid in the mutant strain. This is the first report on the whole biosynthetic pathway of fusidic acid in F. coccineum. SIGNIFICANCE AND IMPACT OF THE STUDY: This study obtain the genetic basis for the biosynthesis of fusidic acid which could be beneficial for the molecular modifications of F. coccineum to further increase its yield by fermentation in future, and established the foundation to reveal the mechanism of the high-yield of the mutant strain.

Effects of amino acids on the fermentation of inulin or glucose to produce R,R-2,3-butanediol using Paenibacillus polymyxa ZJ-9.

This study investigated the effects of different amino acids on the fermentation of pure inulin and glucose using Paenibacillus polymyxa ZJ-9 in order to improve the production of R,R-2,3-butanediol (R,R-2,3-BD) respectively. The inulin extract from Jerusalem artichoke tubers contained 19 common amino acids, which were detected by HPLC. Arg featured the highest content (1290 mg l-1 ). A single add-back experiment of 20 common amino acids indicated that Asn, Ser, His and Arg are key amino acids in R,R-2,3-BD synthesis during inulin fermentation using P. polymyxa ZJ-9. The corresponding yields of R,R-2,3-BD reached 24·32, 22·32, 22·03 and 21·04 g l-1 after the four key amino acids (1·5 g l-1 each) and glucose were evaluated in this fermentation. The yields were considerably higher than that of the control group (12·11 g l-1 ). With the addition of the mixture of four amino acids (1·5 g l-1 each), the highest yields of R,R-2,3-BD (25·07 and 17·47 g l-1 ) were obtained with the increase of 107·0 and 89·1% during the fermentation of glucose and pure inulin respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: Paenibacillus polymyxa is a micro-organism with a reported potential for industrialized production of R,R-2,3-butanediol. The nitrogen sources have a significant effect on R,R-2,3-butanediol formation using P. polymyxa. This study demonstrated a highly efficient new method to improve the yield of R,R-2,3-butanediol without adding other nitrogen sources except amino acids during the fermentation. This will therefore decrease the production cost of R,R-2,3-butanediol and provide a new strategy for promoting synthesis of amino acid-dependent products.