Ecological Risk Assessment of Soil Heavy Metals and Pesticide Residues in Tea Plantations

Tea plantations have used many synthetic chemicals to ensure performance and control of pests. This has led to increased contamination of soils and reduced tea growth. We assessed the levels of heavy metals, including Cd, Cr, Pb, Cu, Ni, Zn, Hg, As, and pesticide residues, such as HCHs, biphenyl chrysanthemum ester, methamidophos, imidacloprid, permethrin, in the soil of tea plantations of Taiwan, Tibet, Guangdong, and Fujian. The Potential Ecological Risk Index and the Nemerow comprehensive pollution index were used to analyze the data. The results showed that risk indices in Tibet, Guangdong and Fuzhou were considered as moderate ecological harm level. Ecological risk assessment index of Anxi organic and Anxi conventional tea gardens suggested a "low" risk level. The Nemerow comprehensive pollution indices for soil pesticide residues in the tea plantations of Taiwan, Tibet, Anxi organic and Anxi conventional were considered mild. Guangdong and Fuzhou had values suggesting "slight pollution” levels. According to National Soil Environmental Quality Standard (GB15618-1995), soil in tea plantations in Taiwan, Tibet, and Anxi conventional matched the national first grade of soil quality and those from Guangdong, Fuzhou, and Anxi organic tea garden matched the national second grade

8-Azatetracyclines: Synthesis and Evaluation of a Novel Class of Tetracycline Antibacterial Agents

bS Supporting Information ABSTRACT: A novel series of fully synthetic 8-azatetracyclines was prepared and evaluated for antibacterial activity. Compounds were identified that overcome both efflux (tet(K)) and ribosomal protection (tet(M)) tetracycline resistance mechanisms and are active against Gram-positive and Gram-negative organisms. Two compounds were identified that exhibit comparable efficacy to marketed tetracyclines in in vivo models of bacterial infection. The tetracycline class of antibacterial agents has seen wide-spread clinical use for over 50 years due to its broad spectrum anti-bacterial activity.1 Tetracyclines inhibit bacterial growth by prevent-ing protein biosynthesis through binding to the 30S ribosome

[1]研究活動

Protein sequences of the ABCA transporters of the eight species. (XLSX 25 kb

A heterozygous moth genome provides insights into herbivory and detoxification

How an insect evolves to become a successful herbivore is of profound biological and practical importance. Herbivores are often adapted to feed on a specific group of evolutionarily and biochemically related host plants1, but the genetic and molecular bases for adaptation to plant defense compounds remain poorly understood2. We report the first whole-genome sequence of a basal lepidopteran species, Plutella xylostella, which contains 18,071 protein-coding and 1,412 unique genes with an expansion of gene families associated with perception and the detoxification of plant defense compounds. A recent expansion of retrotransposons near detoxification-related genes and a wider system used in the metabolism of plant defense compounds are shown to also be involved in the development of insecticide resistance. This work shows the genetic and molecular bases for the evolutionary success of this worldwide herbivore and offers wider insights into insect adaptation to plant feeding, as well as opening avenues for more sustainable pest management.Minsheng You … Simon W Baxter … et al

Artificial floating islands for water quality improvement

Artificial floating islands (AFIs) are variation of wetland treatment systems for water quality improvement. This paper provides a review concerning AFIs in terms of their development, classification and applications in the removal of nutrients, heavy metals and chemical oxygen demand (COD) on waterways. The role of microorganisms, aquatic plants and aquatic animals in AFIs for water decontamination and purification was also discussed. Additionally, some key factors influencing the AFIs’ performances were discussed and comparisons between AFIs and constructed wetlands were reviewed. Finally, further perspectives of artificial floating islands were identified to possibly improve their performances. The understanding of the mechanisms in AFIs that drive removal of various contaminants to improve water quality is crucial, which were also highlighted in this paper.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Electrochemical Corrosion and Critical Pitting Temperature of S32750 Super Duplex Stainless Steel in NaCl Solution

The electrochemical corrosion behavior and critical pitting temperature (CPT)of S32750 super duplex stainless steel in 3.5%NaCl solution were investigated by electrochemical techniques. The morphologies of the steel before after pitting corrosion were observed by scanning electron microscope. The CPT of the S32750 steel was identified as 71 ℃. A passive film could form on the steel surface when the solution temperature was below the CPT. While, when the solution temperature was above the CPT, pitting corrosion occurred on the steel surface as the result of the breakdown of the passive film due to the increase of the Cl~- activity. Pitting corrosion became more serious with the increasing temperature. Moreover, the corrosion models of the steel below and above the CPT were sketched respectively