Establishment of a comprehensive method to derive seawater quality criteria of BDE-47 in China.

2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is an emerging toxic organic pollutant widely detected in territorial waters. Accordingly, establishing the seawater quality criteria (SWQC) for BDE-47 is of significant importance to protect the marine ecosystems. In this study, published ecotoxicity data of BDE-47 to aquatic species in China were collected, and acute and chronic toxicity tests were carried out on saltwater aquatic organisms from 5 phyla and 8 families widely existed in the Chinese marine environment. Static acute toxicity tests and renewed chronic toxicity tests were adopted. The scientific theories and technical methods of the United States Environmental Protection Agency (US EPA), Canada, the European Union (EU), and the Netherlands on water quality criteria guidelines, as well as the Chinese freshwater quality criteria guidelines were compared. Then an integrated method of SWQC derivation was introduced through comprehensive consideration. Afterward, the SWQC of BDE-47 was derived based on the ecotoxicity data. The SWQC includes short-term seawater quality criteria (S-SWQC), long-term seawater quality criteria (L-SWQC), and serious risk concentration for the ecosystem (SRCeco). And they were derived and recommended as 7.90 µg/L, 0.217 µg/L, and 3.65 µg/L, respectively. This study served as a specific example to quantitatively studies the differences between different scientific theories and technique methods. The derivation process and improvement of SWQC for BDE-47 provide support for the future revision of water quality criteria in China.

A novel major facilitator transporter TrSTR1 is essential for pentose utilization and involved in xylanase induction in Trichoderma reesei.

Trichoderma reesei (teleomorph Hypocrea jecorina) is an industrially important filamentous fungus for glycoside hydrolases production, with its xylanolytic enzymes widely applied in many areas. However, the molecular mechanisms underlying xylanase expression are still insufficiently understood. In particular, the effect of sugar transporter on the induction of xylanase expression is unclear. In this work, we identified a novel major facilitator transporter TrSTR1 that is capable of transporting xylose by using a xylose utilization system in Saccharomyces cerevisiae. In T. reesei, TrSTR1 is essential for the utilization of d-xylose, l-arabinose, and even their downstream metabolites D-xylitol and L-arabitol. TrSTR1 is also involved in the induction of xylanase expression since both the xylanase activity and extracellular protein concentration in the Tu6△str1 strain were decreased, which further confirmed by a qRT-PCR analysis of the transcript levels of the key transcriptional regulators. Our observations provide new insights into connections between pentose utilization and xylanase production in T. reesei.

[High-quality total RNA extraction from medicinal plant Aquilaria sinensis].

OBJECTIVE: It is quite difficult to isolate total RNA from Aquilaria sinensis due to the complexity of its secondary metabolites. In order to obtain the high-quality RNA, we investigated sampling method and RNA extraction from both normal and agilawood tissues of the plant. METHODS: Five methods such as modified CTAB-LiCl method, modified CTAB-LiCl method with no water-bath, SDS-acid phenol method, modified guanidinium thiocyanate-CTAB method and EASYspin RN09 RNA isolation kit were used to extract RNA from leaves, branches, white wood samples, agilawood samples of A. sinensis, respectively. RESULTS: Total RNA was stable for 5 hours at room temperature after extracted from A. sinensis branches. EASYspin RN09 RNA isolation kit was the best extraction method for the leaf while modified guanidinium thiocyanate-CTAB method was the best for the other samples. CONCLUSION: A great quantity of RNAs can be isolated from samples of white wood and agilawood wood, respectively. Their ratios of 28S : 18S are in the range of 1.2 - 1.4 and RINs are between 6.8 - 7.5. These RNAs can be applied in transcriptome sequencing.

Derivation of copper water quality criteria in Bohai Bay for the protection of local aquatic life and the ecological risk assessment.

Developing effective marine water quality criteria (WQC) is crucial for controlling marine contamination and protecting marine life. The WQC for copper is urgently needed due to the toxicity and widespread of copper contamination. In this work, both short-term water quality criteria (SWQC) and long-term water quality criteria (LWQC) under 10 % effect endpoints were derived by using the model averaging of species sensitivity distribution (SSD10) method for Bohai Bay. The WQC values were obtained directly from the hazardous concentration for 5 % of species (HC5) values, which removes the influence of arbitrary assessment factor (AF). Modifications to the acute-chronic ratio (ACR) strategies and the inclusion of the test toxicity data of local species also improved the accuracy and applicability of the WQC values. The derived SWQC and LWQC were 2.21 and 0.45 µg/L, respectively. Furthermore, the overall risk level of copper in Bohai Bay was evaluated by using the risk quotient (RQ) method, and the results showed it was at a moderate-low level. This study provides a new approach for the derivation of the WQC for Cu and the risk assessment of Bohai Bay, which is essential for the protection of local aquatic life and provides guidance to the establishment of the national WQC.

Derivation of copper water quality criteria in the Bohai Sea of China considering the effects of multiple environmental factors on copper toxicity.

Copper has become one of the most important heavy metal pollutants in the environment because of its wide application and high toxicity, but research on water quality criteria (WQCs) on copper is limited, especially the derivation of seawater WQC. In addition, the toxicity of copper in the seawater system is affected by various environmental factors. Therefore, establishing a WQC that meets the characteristics of the regional environment is a top priority. The correlations between four factors of temperature, salinity, pH, dissolved organic carbon (DOC) and the toxic effect values of copper were analyzed in this study, and the temperature was determined as the most influential factor among the four factors in the Bohai Sea. A specific correlation between temperature and the toxic effects of copper was identified, and WQCs were derived based on the identified correlation and the variations of the Bohai Sea's temperature in different seasons by species sensitivity distribution (SSD) method. Under the condition of the winter, spring, autumn, and summer with an average water temperature of 0.09, 15.96, 17.83, and 24.87 °C, the obtained short-term water quality criteria (SWQCs) were 44.29, 4.70, 4.31, and 3.33 µg/L; the long-term water quality criteria (LWQCs) were 18.14, 1.93, 1.77 and 1.36 µg/L. The findings indicated the importance of introducing specific environmental conditions during the derivation process. This work could provide valuable information for pollution prevention and aquatic life protection in the Bohai Sea and provide a valuable reference for the derivation of criteria in other regions alike.