Identifying the Key Role of Plutella xylostella General Odorant Binding Protein 2 in Perceiving a Larval Attractant, (E,E)-2,6-Farnesol.

There is currently a lack of effective olfaction-based techniques to control diamondback moth (DBM) larvae. Identifying behaviorally active odorants for DBM larvae and exploring their recognition mechanisms can provide insights into olfaction-based larval control strategies. Through the two-choice assay, (E,E)-2,6-farnesol (farnesol) was identified as a compound exhibiting significant attractant activity toward DBM larvae, achieving an attraction index of 0.48 ± 0.13. PxylGOBP1 and PxylGOBP2, highly expressed in the antennae of DBM larvae, both showed high affinity toward farnesol. RNAi technology was used to knock down PxylGOBP1 and PxylGOBP2, revealing that the attraction of DBM larvae to farnesol nearly vanished following the knockdown of PxylGOBP2, indicating its critical role in recognizing farnesol. Further investigation into the PxylGOBP2-farnesol interaction revealed the importance of residues like Thr9, Trp37, and Phe118 in PxylGOBP2's binding to farnesol. This research is significant for unveiling the olfactory mechanisms of DBM larvae and developing larval behavior regulation techniques.

A performance evaluation of an immuno-latex chromatography card for the rapid detection of Candida spp.

This report evaluates the performance and species specificity of an immuno-latex chromatography card (ICC) for rapid detection of Candida spp. Double-manipulator single-blind Gram staining smear examination (GSSE) and ICC were used to analyze 354 vaginal discharge specimens (VDS) (including 98 tested as positive by GSSE) from women with suspected candidal vaginitis, simulated specimens with a concentration gradient, and vaginitis causing organism suspensions (0.9% NaCl) of 22 species from nine genera. Limit of detection, semi-quantitative detection performance, total detection performance and species specificity were determined for ICC, and the results were compared with those of the GSSE method. The limits of detection of ICC for Candida spp. in organism suspensions with 0.9% NaCl and simulated specimens were 7 × 106 cells/L and 7 × 108 cells/L respectively. For species specificity, the results were positive for six Candida spp. (C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. krusei and C. guilliermondii) and negative for the remaining 16 species (C. lusitaniae, Saccharomyces cerevisiae; three Gram-positive coccus species, four Gram-negative bacillus species, three Gram-negative coccus species and four common microbes causing vaginal infection) from eight genera. The overall sensitivity, specificity, accuracy, positive predictive value and negative predictive value of ICC for VDS were 93.81%, 99.10%, 97.31, 98.14% and 96.90%, respectively. The above indicators in the 98 VDS evaluated as positive were 84.39%, 92.86%, 86.74%, 96.72% and 70.27%, respectively. In summary, ICC offered better specificity, sensitivity, positive predictive value and negative predictive value for the detection of Candida spp. in VDS.