Optimization extraction of rosemary essential oils using hydrodistillation with extraction kinetics analysis.

Rosemary (Rosmarinus officinales L. (Labiatae)) is one of the major economic crops in the world, and rosemary essential oil (REO) is one of the top products derived from rosemary and has excellent commercial prospects. Many factors affect the yield of REO extracted by hydrodistillation (HY). This study was proposed to identify and analyze these factors to maximize the yield of essential oils and reduce the cost. First, two different single-factor extraction experiments were conducted, (1) adding NaCl and (2) using various organs of the plant, to determine the influence of each factor on the oil yield. Based on single-factor experiments, the orthogonal experiments (L9, 33) were designed to determine the optimal conditions for the extraction of rosemary oil. Meanwhile, the kinetic extraction analysis of the test data was carried out. The results revealed that the highest oil yield was achieved when rosemary leaves were crushed to 2 cm, the ratio of water to the material was 1:3, and NaCl concentration was 5%. A simple first-order kinetic model has also proved to be an acceptable general choice and allows to predict the output of extraction operations overtime accurately and robustly in practice. This study provides a reference scheme for using hydrodistillation to extract rosemary essential oil.

Phytoremediation of potentially toxic elements in a polluted industrial soil using Poinsettia.

Potentially toxic elements (PTEs) pollution has become a serious environmental threat, particularly in developing countries such as China. In response, there is a growing interest in phytoremediation studies to identify plant species as designated hyperaccumulators of PTEs in polluted soils. Poinsettia was selected as a candidate species for phytoremediation of six PTEs (Zn, Pb, Hg, Cr, As, Cu) in this study. A pot cultivation experiment (randomized incomplete block experimental design with 5 treatments and 4 blocks) was conducted using contaminated soils gathered from an industrial area in southcentral China. The bioaccumulation factor (BAF), translocation factor (TF), and bioconcentration factor were analyzed to determine the phytoremediation potential of poinsettia potted in different ratios of polluted soils. One-way ANOVA with post-hoc Tukey's test showed that poinsettia had significant uptake of Zn, Pb, Cu (BAF < 1 and TF < 1, p < 0.05) and Hg (BAF < 1 and TF > 1, p < 0.05). Poinsettias can therefore effectively accumulate Zn, Pb, and Cu in their lateral roots while extracting and transferring Hg into their leaves. Moreover, poinsettia exhibited tolerance towards As and Cr. Interestingly, it was also observed that PTEs can inhibit the height of potted poinsettia at a certain concentration.

Characterization of mitochondrial genomes of three Andrena bees (Apoidea: Andrenidae) and insights into the phylogenetics.

Andrena is a large bee genus of >1500 species, which includes many important pollinators of agricultural systems. In this study, we present three mitochondrial genomes (mitogenomes) of Andrena species, which are the pollinators of Camellia oleifera. Compared with putative ancestral gene arrangement of insects, the three mitogenomes present identical gene rearrangement events, including local inversion (trnR) and gene shuffling (trnQ/trnM, trnK/trnD, and trnW/trnC-trnY). Most PCGs initiate with standard ATN codon and share the stop codon of TAA or TAG, whereas truncated stop codon T was detected in the atp6 gene of A. chekiangensis. Furthermore, the nad4 gene end with a single T in all three Andrena species. All tRNAs could be folded into clover-leaf secondary structure except for trnS1, with the dihydrouracil (DHU) arm forming a simple loop. Phylogenetic analysis is performed on 17 Andrena mitogenomes. Maximum likelihood and Bayesian methods generate identical topology, in which A. hunanensis and A. striata form a group and are close to A. camellia. Although A. chekiangensis is also difficult to be distinguished from A. camellia by morphological methods, A. chekiangensis and A. haemorrhoa form a clade and are grouped with the other taxa of the genus Andrena.

Prevalence of the mcr-1 colistin resistance gene in extended-spectrum ß-lactamase-producing Escherichia coli from human faecal samples collected in 2012 in rural villages in Shandong Province, China.

Since its initial discovery in China in 2015, the plasmid-mediated colistin resistance gene mcr-1 has been reported in Escherichia coli isolated from clinical samples, animals and meat worldwide. In this study, 706 extended-spectrum ß-lactamase (ESBL)-producing E. coli from 411 persons were detected in a collection of faecal samples from 1000 rural residents in three counties in Shandong Province, China. These isolates were screened for mcr-1 and phenotypic colistin resistance. The gene was found in 3.5% of the isolates (from 4.9% of persons) from all three counties. All isolates with phenotypic colistin resistance carried mcr-1. These data indicate that commensal carriage of ESBL-producing E. coli with mcr-1 among persons in rural China was already present in 2012 and that mcr-1 was the most important colistin resistance mechanism. Interventions are necessary to minimise further dissemination of mcr-1, which would limit the future usefulness of colistin as a last-resort antibiotic.