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Erythromycin is a commonly used broad-spectrum antibiotic, but resistance to this antibiotic makes its use less effective. Considerable efforts, beside finding alternatives, are needed to enhance its antimicrobial effect and stability against bacteria. Tetrahedral framework nucleic acids (tFNAs), a novel delivery vehicle with a three-dimensional nanostructure, have been studied as a carrying platform of antineoplastic drugs. In this study, the use of tFNAs in delivering erythromycin into Escherichia coli ( E. coli ) was investigated for the first time. The tFNAs vehicle increased the bacterial uptake of erythromycin and promoted membrane destabilization. Moreover, it increased the permeability of the bacterial cell wall, and reduced drug resistance by improving the movement of the drug across the membrane. The tFNAs-based delivery system enhanced the effects of erythromycin against E. coli . It may therefore provide an effective delivery vehicle for erythromycin in targeting antibiotic-resistant bacteria with thick cell wall.

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a highly polyphagous herbivore. This research was conducted to compare the development of B. tabaci reared in a multi‐plant treatment (polyculture) with those in single‐plant treatments (monocultures). Adult B. tabaci females fed on a mixture of tomato, cabbage, cotton, cucumber, and kidney bean survived longer and laid more eggs than those fed exclusively on one of these plant species. Egg numbers per plant laid in the polyculture treatment were positively correlated with those laid on the same plant species in the monoculture treatments, and egg numbers per plant laid on tomato, cotton, and cucumber in the polyculture were significantly higher than those laid on the same plants in the monocultures. Concentrations of total protein and trehalose in B. tabaci were not significantly different after 7 days of feeding in the respective treatments, but activities of superoxide dismutases (SOD) and alkaline phosphatase (AKP) of B. tabaci in polyculture were lower than those in monoculture. Conversely, activities of trehalase, sucrase, and amylase in B. tabaci kept in polyculture were higher than those of insects from the monoculture. In each of the monoculture treatments, there was a negative correlation between AKP in B. tabaci and oviposition, and also between AKP and amylase. SOD and sucrase activities in B. tabaci were positively correlated with polyphenol oxidase (PPO) and peroxidase (POD) activities in plants. In the plants damaged by whiteflies in the polyculture treatment, activities of SOD in cucumber, PPO in cotton and kidney bean, and POD in tomato and cucumber were lower than those in the monoculture treatments, whereas SOD in cabbage and catalase (CAT) in tomato in the polyculture treatment were higher than those in the monoculture treatments.

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Metarhizium anisopliae as an essential entomopathogenic fungus has been known to produce destruxins (a kind of cyclo-peptidic mycotoxins) and blastospores in submerged culture. Blastospores and destruxins are candidates for insecticides, but the relations of both productions and the impact factors are unclear yet. In this study, we investigated the effects of inoculums, rotation, dissolved oxygen (DO) on the production of blastospores and destruxins A and B (DA and DB) in submerged culture of M. anisopliae strain MaQ01. The results indicated that DO levels were regulated by inoculum amounts and rotation speeds, meanwhile, the production of DA, DB and blastospores was also closely influenced by those factors. Totally, when DO value was more than 40%, the higher productions of destruxins and blastospores were achieved, by contrast, lower than 40% of DO values resulted in lower productions. The regression analysis suggested that the production of DA, DB and blastospores was positively correlated with the DO levels. Meanwhile, the positive correlations between the productions of DA or DB and blastospores were also found. Briefly, when the rotation is 150 r min-1 and the inoculum is 1.0×10 6 spore mL-1 , the DA, DB and blastospores achieved the best production of 61.81 mg mL-1 , 24.74 mg mL-1 and 5.73×10 6 spore mL-1 , respectively. In addition, the pathogenicities of blastospores and conidia against Plutella xylostella were bioassayed. The higher mortalities of P. xylostella were totally recorded in blastospore treatments than in conidia treatments, especially in lower dosages and earlier periods. Our research will give some new insights to production of destruxins and blastospores by using M. anisopliae.

Ammonia (NH 3) volatilized from agricultural production and its secondary aerosols contribute greatly to air pollution. Different long-term crop straw management practices may significantly affect the soil fertility and soil nitrogen cycle, however, the effect on NH 3 volatilization has not been well studied. Therefore, a one-year field experiment was conducted to evaluate the effect of straw incorporation on NH 3 volatilization from subtropical calcareous agricultural soil from a longterm perspective, including four treatments: synthetic fertilizer (CK); synthetic fertilizer incorporation with 100% or 50% of the previous season's crop straw (SI1 and SI2, respectively); and synthetic fertilizer incorporation with 50% burned crop straw (SI2B). Soil NH 3 volatilizations were monitored through a wheat-maize rotation year by using a dynamic chamber method. The results demonstrated that NH 3 volatilization primarily occurred within 38 days and 7-10 days following nitrogen fertilization events for the wheat and maize seasons, respectively. Different crop straw management practices mainly impacted the NH 3 flux of the basal fertilization rather than the topdressing fertilization; long-term crop straw incorporation effectively lowered NH 3 loss (35.1% for SI1 and 16.1% for SI2 compared to CK; and the inhibiting effect increased with increasing straw amount, possibly contributed by the high straw carbon/nitrogen ratio, and enhanced microbial activity, which contributed to inorganic nitrogen immobilization and lower ammonium content in the topsoil. However, SI2B significantly increased (29.9%) the annual NH 3 flux compared with SI2, indicating that long-term 100% straw incorporation could be a promising straw management practice for mitigating NH 3 loss and increasing soil fertility.

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