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Doxycycline hydrochloride and florfenicol combination (DoxHcl&FF) is an effective treatment for respiratory diseases. In the study, our objective was to evaluate the activity of DoxHcl&FF against Actinobacillus pleuropneumoniae (APP) in porcine pulmonary epithelial lining fluid (PELF) and the optimal dosage scheme to avoid the development of resistance. The DoxHcl&FF was administered intramuscularly (IM) at 20 mg/kg, and the PELF was collected at different time points. The minimum inhibitory concentration (MIC) and time-mortality curves were also included in the study. Based on the sigmoid Emax equation and dose equations, the study integrated the in vivo pharmacokinetic data of infected pigs and ex vivo pharmacodynamic data to obtain the area under concentration time curve (AUC0-24h)/MIC values in PELF and achieve bacteriostatic activity, bactericidal activity and the virtual eradication of bacteria. The study showed that the combination of DoxHcl and FF caused no significant changes in PK parameters. The peak concentration (Cmax) of FF in healthy and diseased pigs was 8.87 ± 0.08 μg/mL and 8.67 ± 0.07 μg/mL, the AUC0-24h were 172.75 ± 2.52 h·μg/mL and 180.22 ± 3.13 h·μg/mL, the Cmax of DoxHcl was 7.91 ± 0.09 μg/mL and 7.99 ± 0.05 μg/mL, and the AUC0-24h was 129.96 ± 3.70 h·μg/mL and 169.82 ± 4.38 h·μg/mL. DoxHcl&FF showed strong concentration-dependent tendencies. The bacteriostatic, bactericidal, and elimination activity were calculated as 5.61, 18.83 and 32.68 h, and the doses were 1.37 (bacteriostatic), 4.59 (bactericidal) and 7.99 (elimination) mg/kg. These findings indicated that the calculated recommended dose could assist in achieving more precise administration, increasing the effectiveness of DoxHcl&FF treatment for APP infections.

Theranostic nanosystem has been demonstrated great potential in real-timely monitoring drug biodistribution and therapeutic response. It is still a challenge to fabricate a theranostic nanosystem that possesses the properties of good biocompatibility, a high magnetic resonance imaging (MRI) sensitivity, and stimuli-responsive drug release for the diagnosis and treatment of hepatocellular carcinoma. Here, a pH-responsive micelle, which was self-assembled from biodegradable poly(amino acid) block copolymer mPEG-PAsp(DIP)-co-PLLeu, was constructed to load both chemotherapeutic paclitaxel (PTX) and MRI contrast agent superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs/PTX-coloaded PDPL micelle (SPIONs/PTX-PDPL) had a hydrodynamic particle size of 134.5 ± 11.2 nm. The theranostic SPIONs/PTX-PDPL not only effectively delivered PTX and SPION into Bel-7402 cancer cells but also rapidly released PTX in acidic lysosome to induce cell apoptosis. Meanwhile, in vitro MR imaging sensitively detected the liver cancer cells after co-incubation with SPIONs/PTX-PDPL micelle. The SPIONs/PTX-PDPL micelle is a potential theranostic nanosystem in terms of the simultaneous chemotherapy and MR imaging of hepatocellular carcinoma.

Wheat is one of the most important staple food crops in many parts of the world. Nitrogen (N) is often considered to be the most important mineral nutrient element for crop growth and development. Nitrogen use efficiency (NUE) comprises nitrogen uptake efficiency (NUpE) and nitrogen utilization efficiency (NUtE). We constructed a high-density genetic map using a set of 184 recombinant inbred lines (RILs) derived from the cross ‘Tainong 18 × Linmai 6’ (TL-RILs). In this study, 14 seedling traits and 17 maturity traits related to NUE and agronomic traits of wheat were investigated using the TL-RILs under hydroponic culture trials with high N (HN), moderate N (MN) and low N (LN) levels in two time frames, and under field trials with HN and LN levels in two growing seasons. A total of 121 and 130 quantitative trait loci (QTLs) we detected at seedling and maturity stages, respectively. Of these, 47 relatively high-frequency QTLs (RHF-QTLs) and 16 QTL clusters were found. The most important cluster, C9, included morphological, biomass, yield, NUpE and NUtE traits at the same time. The contributions for most QTLs were high, with the highest contribution of 30.00%. Seventeen RHF-QTLs were detected in this cluster, and it showed a favorable relationship between the RHF-QTLs for breeding programs. The markers in the region of cluster C9 should be valuable in marker-assisted selection (MAS). The sequence of DArT marker D-3940950 in the C9 region was identified to the RhtB1 gene with the similarity of 100% by BLAST against the Chinese Spring genome (IWGSCv1.0). The correlation analysis suggested that the morphological/biomass traits and eight yield traits can be considered as the primary morphological indexes for the evaluation of NUE instead of using element determinations, and the outcomes make it easy to identify NUE on a large scale.

Background Recent results demonstrated that either non-coding or coding genes generate phased secondary small interfering RNAs (phasiRNAs) guided by specific miRNAs. Till now, there is no studies for phasiRNAs in Panax notoginseng (Burk.) F.H. Chen (P. notoginseng), an important traditional Chinese herbal medicinal plant species. Methods Here we performed a genome-wide discovery of phasiRNAs and its host PHAS loci in P. notoginseng by analyzing small RNA sequencing profiles. Degradome sequencing profile was used to identify the trigger miRNAs of these phasiRNAs and potential targets of phasiRNAs. We also used RLM 5’-RACE to validate some of the identified phasiRNA targets. Results After analyzing 24 small RNA sequencing profiles of P. notoginseng, 204 and 90 PHAS loci that encoded 21 and 24 nucleotide (nt) phasiRNAs, respectively, were identified. Furthermore, we found that phasiRNAs produced from some pentatricopeptide repeat-contain (PPR) genes target another layer of PPR genes as validated by both the degradome sequencing profile and RLM 5’-RACE analysis. We also found that miR171 with 21 nt triggers the generations of 21 nt phasiRNAs from its conserved targets. Conclusions We validated that some phasiRNAs generated from PPRs and TASL genes are functional by targeting other PPRs in trans. These results provide the first set of PHAS loci and phasiRNAs in P. notoginseng, and enhance our understanding of PHAS in plants. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-4331-0) contains supplementary material, which is available to authorized users.