Objective:To test the HIV virus nucleic acid using immunoblot method (Western blotting, WB) and to follow-up with the negative and indeterminate samples in the Dujiangyan area, compare the WB and nucleic acid results before and after followed-up, and try to reduce the WB band′s false-negatives and false-positives.Methods:The 286 suspected HIV infection samples in the Dujiangyan region from January to October 2021 were confirmed by WB, the HIV virus load were tested for the samples that were WB negative and WB indeterminate, those patients were followed-up with epidemiological history and viral load results, and the results before and after tracking were compared.Results:In the 286 samples of suspected HIV infection included in this study, we reported 213 (74.48%) WB positive, 37 WB negative (12.94%), and 36 WB indeterminate (12.58%); 10 of 37 WB negative samples were followed-up; 18 of 36 WB indeterminate samples were followed-up. Among the followed-up WB negative and indeterminate samples, 17 of them had virus nucleic acid detection prior to the follow-up, and all of them turned positive after following-up. The others with no previous virus nucleic acid detection were confirmed to be negative.Conclusions:Among the followed-up samples, 2 samples were false-negative in WB negative results, and 3 were false-positive in WB indeterminate results. The viral nucleic acid must be tested and followed-up in WB negative and indeterminate samples.

Different neutralizing agents were used as pH controller to investigate their effects on the growth and succinic acid production of Actinobacillus succinogenes NJ113. The fermentation results showed that Ca(OH)2, CaCO3 and NH4OH were not suitable for succinic acid production by A. succinogenes NJ113 because of their negative effects on cell growth. When Na-base was used, cells would flocculate and lump, and due to the sodium ion concentration reaching to a high level, OD660 dropped sharply after 12 h of fermentation. Mg-base was better because there was no significant inhibition by magnesium ion. Two combined neutralizing agents were used to maintain pH level, one with NaOH and Mg(OH)2 while the other with Na2CO3 and Mg(OH)2. The optimum ratios of the combined neutralizing agents were both 1:1 (g:g) when using 100 g/L glucose. When NaOH and Mg(OH)2 were chosen with the ratio of 1:1(g:g), 69.8 g/L of the succinic acid and 74.5% of the yield was obtained.
Actinobacillus ; genetics ; metabolism ; Fermentation ; Hydrogen-Ion Concentration ; Industrial Microbiology ; Magnesium Hydroxide ; pharmacology ; Sodium Hydroxide ; pharmacology ; Succinic Acid ; metabolism

We investigated the effect of adding intermediate metabolites on cell growth and succinate production. The yield of succinic acid achieved to the highest when 0.5 g/L phosphoenolpyruvic acid (PEP) was added. According to the metabolic network of Actinobaccilus succinogenes NJ113, the metabolic flux was calculated by metabolic flux analysis. The ratio of hexose monophosphate pathway to glycolytic pathway increased from 39.4:60.3 to 76.8:22.6 after adding 0.5 g/L PEP, thus the reducing power was better balanced. The flux of PEP to oxaloacetate was 23.8% higher, which made the succinic acid flux improve from 99.8 mmol/(g DCW x h) to 124.4 mmol/(g DCW x h) and the flux of acetic acid and formic acid decreased by 22.9% and 15.4%, respectively. The key enzyme activity analysis showed that the specific activity of PEP carboxykinase reached to 1910 U/mg with 0.5 g/L PEP addition, which was 74.7% higher than the control; and the specific activity of pyruvate kinase decreased by 67.5%. Finally, the concentration of succinic acid was 29.1 g/L with the yield of 76.2%.
Actinobacillus ; metabolism ; Anaerobiosis ; Culture Media ; Culture Techniques ; methods ; Fermentation ; Phosphotransferases (Paired Acceptors) ; metabolism ; Succinic Acid ; metabolism