Immune persistence after different polio sequential immunization schedules in Chinese infants.

Trivalent oral poliovirus vaccine (tOPV) has been withdrawn and instead an inactivated poliovirus vaccine (IPV) and bivalent type 1 and type 3 OPV (bOPV) sequential immunization schedule has been implemented since 2016, but no immune persistence data are available for this polio vaccination strategy. This study aimed to assess immune persistence following different polio sequential immunization schedules. Venous blood was collected at 24, 36, and 48 months of age from participants who had completed sequential schedules of combined IPV and OPV in phase III clinical trials. The serum neutralizing antibody titers against poliovirus were determined, and the poliovirus-specific antibody-positive rates were evaluated. A total of 1104 participants were enrolled in this study. The positive rates of poliovirus type 1- and type 3-specific antibodies among the sequential immunization groups showed no significant difference at 24, 36, or 48 months of age. The positive rates of poliovirus type 2-specific antibody in the IPV-IPV-tOPV group at all time points were nearly 100%, which was significantly higher than the corresponding rates in other immunization groups (IPV-bOPV-bOPV and IPV-IPV-bOPV). Immunization schedules involving one or two doses of IPV followed by bOPV failed to maintain a high positive rate for poliovirus type 2-specific antibody.

Differences in rectal amino acid levels determine bacteria-originated sex pheromone specificity in two closely related flies.

Sex pheromones are widely used by insects as a reproductive isolating mechanism to attract conspecifics and repel heterospecifics. Although researchers have obtained extensive knowledge about sex pheromones, little is known about the differentiation mechanism of sex pheromones in closely related species. Using Bactrocera dorsalis and Bactrocera cucurbitae as the study model, we investigated how the male-borne sex pheromones are different. The results demonstrated that both 2,3,5-trimethylpyrazine (TMP) and 2,3,5,6-tetramethylpyrazine (TTMP) were sex pheromones produced by rectal Bacillus in the two flies. However, the TMP/TTMP ratios were reversed, indicating sex pheromone specificity in the two flies. Bacterial fermentation results showed that different threonine and glycine levels were responsible for the preference of rectal Bacillus to produce TMP or TTMP. Accordingly, threonine (glycine) levels and the expression of the threonine and glycine coding genes were significantly different between B. dorsalis and B. cucurbitae. In vivo assays confirmed that increased rectal glycine and threonine levels by amino acid feeding could significantly decrease the TMP/TTMP ratios and result in significantly decreased mating abilities in the studied flies. Meanwhile, decreased rectal glycine and threonine levels due to RNAi of the glycine and threonine coding genes was found to significantly increase the TMP/TTMP ratios and result in significantly decreased mating abilities. The study contributes to the new insight that insects and their symbionts can jointly regulate sex pheromone specificity in insects, and in turn, this helps us to better understand how the evolution of chemical communication affects speciation.

Rectal bacteria produce sex pheromones in the male oriental fruit fly.

Volatile molecules produced by the microbiota play a primary role in chemical communication between insects,1 and direct production of pheromone components by the microbiota is one of the most obvious mechanisms.2 Here, we investigated the production of male-borne sex pheromones of the oriental fruit fly, Bactrocera dorsalis. As observed in previous studies,3,4 2,3,5-trimethylpyrazine (TMP) and 2,3,5,6-tetramethylpyrazine (TTMP) are sex pheromones produced in the male rectum. Mature virgin females are strongly attracted to TMP and TTMP. 16S rRNA sequencing results show that the rectal bacteria are dominated by Bacilli that harbor the pathway to produce TMP and TTMP.5-8 The levels of Bacilli, TMP, and TTMP in the male rectum can be significantly decreased by feeding male flies with antibiotics. In vitro assays show that Bacillus species isolated from the male rectum can produce TMP and TTMP when provided with the substrates glucose and threonine, the levels of which are significantly higher in the rectum of mature males. These findings highlight the influence of microbial symbionts on insect pheromones and provide an example of direct bacterial production of pheromones in insects.

Egg-Surface Bacteria Are Indirectly Associated with Oviposition Aversion in Bactrocera dorsalis.

Finding a suitable oviposition site is a challenging task for a gravid female fly, because the hatched maggots have limited mobility, making it difficult to find an alternative host. The oriental fruit fly, Bactrocera dorsalis, oviposits on many types of fruits. Maggots hatching in a fruit that is already occupied by conspecific worms will face food competition. Here, we showed that maggot-occupied fruits deter B. dorsalis oviposition and that this deterrence is based on the increased ß-caryophyllene concentration in fruits. Using a combination of bacterial identification, volatile content quantification, and behavioral analyses, we demonstrated that the egg-surface bacteria of B. dorsalis, including Providencia sp. and Klebsiella sp., are responsible for this increase in the ß-caryophyllene contents of host fruits. Our research shows a type of tritrophic interaction between micro-organisms, insects, and insect hosts, which will provide considerable insight into the evolution of insect behavioral responses to volatile compounds.

V6 O13-δ @C Nanoscrolls with Expanded Distances between Adjacent Shells as a High-Performance Cathode for a Knittable Zinc-Ion Battery.

Herein, the defective vanadate oxide (V6 O13-δ )/C (denoted as DVOC) nanoscrolls with large distance between adjacent shells are constructed as a cathode material for ZIBs. By simultaneously enlarging the distance between adjacent shells and engineering the defective structure for oxide crystal, the DVOC nanoscrolls achieve fast kinetics, high reversibility and good energy storage capability. The formation process of DVOC nanoscrolls is investigated and a self-assembling-rolling sequential mechanism is disclosed. Moreover, the fiber-shaped flexible ZIBs are fabricated based on the DVOC cathode. Their admirable volumetric energy density, good high rate capability and excellent cycling stability demonstrate the superiority of the unique structure. Therefore, this work not only introduces a new strategy to improve the properties of vanadium oxides but also provide a new strategy for the design of knittable power sources for flexible electronics.

[Preparation of organic-inorganic hybrid poly(ionic liquids) material and evaluation of the adsorption to dyes].

An organic-inorganic hybrid poly(ionic liquids) material was prepared by using allyl triethoxysilane and 1-vinyl-3-octyl imidazolium bromide ionic liquids via combining free radical polymerization with sol-gel process. The prepared hybrid poly(ionic liquids) material was characterized by infrared spectroscopy and scanning electron microscopy. The adsorption properties of the prepared material to common dyes such as tartrazine, sunset yellow, amaranth and allura red were investigated. The results showed that the prepared poly(ionic liquids) material had excellent adsorption properties to sunset yellow and allura red. The adsorption capacities were 29.20 and 86.17 mg/g, respectively. When the adsorption time was 5 min, the material showed a fast adsorption rate to allura red and sunset yellow, which were 87.5% and 72.8% of the balance adsorption capacities, respectively.

[Effect of 2-phenoxyethanol on potency of Sabin inactivated poliomyelitis vaccine and its safety].

OBJECTIVE: To investigate the effect of 2-phenoxyethanol on potency of Sabin inactivated poliomyelitis vaccine (IPV). METHODS: Sabin IPV samples containing 5 mg or 7 mg 2-phenoxyethanol each dosage respectively were placed separately at 4 degrees C, 37 degrees C for 2 days and 7 days. D-antigen contents were tested with ELISA method. Then neutralizing antibodies in mice and guinea pigs were detected. The safety experiment was performed according to unusual toxicity test of China requirement for biological product. RESULTS: After addition of 2-phenoxyethanol, the I, II, and III D-antigen contents of Sabin IPV did not change. The antibody levels in mice and guinea pigs were not different between experimental group and control group. Animals were safe during observation period. CONCLUSION: 2-Phenoxyethanol had no effect on potency and safety of Sabin IPV. It can be used as antiseptic for Sabin IPV.