Fate,behavior, and aquatic toxicity of the fungicide IPBC in the Canadian environment

Canadian water quality guidelines (CWQG) for 3‐iodo‐2‐propynyl butyl carbamate (IPBC) were developed based on a review of environmental chemistry, fate, and toxicology of IPBC. IPBC is used in Canada in antisapstain formulations for treatment of freshly sawn lumber, as an industrial mildewcide, and as an antimicrobial. In British Columbia, IPBC is an active ingredient in the most widely used antisapstain formulation (Kop‐Coat NP‐1); 36,020 kg of IPBC were used by lumber mills for antisapstain purposes in 1996. IPBC is moderately soluble in water, and is not likely to adsorb to suspended solids or sediments. It is not persistent in the water column; hydrolysis is expected to be the main route of dissipation. IPBC was reported to affect fathead minnows at levels as low as 0.019 mg L⁻ and Daphnia magna at levels as low as 0.07 mg L⁻¹. It is not expected to bioaccumulate. An interim water quality guideline for the protection of freshwater aquatic life of 1.9 μg L⁻¹ is recommended. This guideline was derived according to the Canadian Council of Ministers of the Environment's (CCME) Protocol for the Derivation of Water Quality Guidelines for the Protection of Aquatic Life, and is intended to be protective of all forms of freshwater aquatic life at all aquatic life stages. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 201–213, 2000     

Azole‐resistant Aspergillus fumigatus isolates carrying TR34/L98H mutations in Taiwan

Cumulative evidence described the emergence and geographical expansion of azole‐resistant A. fumigatus associated with azole treatment failure. To investigate the status of azole resistance in A. fumigatus in Taiwan, we studied 38 A. fumigatus clinical isolates cultivated from 31 patients at two teaching hospitals from 2011 to 2014. Three isolates obtained from respiratory samples of two azole‐naïve patients with pulmonary aspergillosis were found to display multi‐azole resistance and cross resistance to agricultural azole fungicides, and all carried TR₃₄/L98H mutations in cyp51A gene. The prevalence rates of azole resistance were 7.9% and 6.5% based on isolates and patients respectively. A phylogenetic analysis suggested genetic diversity of the TR₃₄/L98H isolates in Taiwan, including a unique genotype distinct from strains outside Taiwan. The result underlines the emergence of such isolates in Taiwan as well, emphasising the importance of further surveillance for azole‐resistant A. fumigatus and implementation of strategies that prevent fungicide‐driven resistance selection.     

5种杀菌剂对甘草生长及菌根效应的影响

通过分析多抗霉素、井冈霉素、甲基托布津、百菌清和多菌灵5种杀菌剂对甘草生长及菌根效应的影响,旨在选出对菌根效应影响最小的杀菌剂,为甘草菌根化栽培提供指导。实验以盆栽甘草为材料,以田间常用浓度灌施不同杀菌剂,处理60 d后测定各处理组的侵染率、侵染密度、生物量指标、光合指标以及有效成分含量。实验结果表明,多菌灵对甘草菌根效应抑制最强,能够显著抑制菌根侵染率,显著抑制甘草的实际光合效率,显著抑制甘草的株高、叶片数、地上鲜重和地下鲜重等生物量指标,对有效成分的含量也有一定的抑制作用;多抗霉素对菌根效应的抑制作用最弱,对菌根侵染率、多个甘草生物量指标以及实际光合效率均无显著影响;其他杀菌剂对菌根效应也有一定的抑制作用,抑制程度介于多菌灵和多抗霉素之间。作者认为杀菌剂对菌根效应的抑制程度可能与杀菌剂的种类有关,建议田间在防治病害时尽量选择多抗霉素等生物杀菌剂。     

Folpet-induced short term cytotoxic and proliferative changes in the mouse duodenum

Folpet, an agricultural fungicide, induces tumors in the mouse gastrointestinal tract, primarily in the duodenum. Bioassays show a threshold for tumors at ~1000?ppm dietary administration. We investigated the early histologic changes to the mouse duodenum in mice fed a diet containing 6000?ppm folpet for 28 days. Reversibility of folpet-induced changes was evaluated after treatment for 28 days and a recovery period of 17 days. Macroscopic changes in the cecum (dilatation) and duodenum (roughening) were evident by day 7, continued through day 28, then returned to normal by recovery day 17. The duodenal mucosa also appeared to be thickened. Macroscopic changes to the forestomach were also evident as a rough surface or depressions; they also decreased in incidence and severity in the recovery animals. Histologic changes of the duodenum (crypt cell hyperplasia, villous hypertrophy, numerous intraepithelial lymphocytes, and elongation of epithelial columnar cells) were evident in all treated mice by day 7 and continued and increased in severity through 28 days of administration. The incidence and severity of these findings was reduced on recovery day 17, indicating reversibility. Histologic changes (epithelial hyperplasia and hyperkeratosis) of the non-glandular squamous epithelium in the forestomach occurred later than the changes to the duodenum. The incidence and severity of these changes also lessened by recovery day 17. These early histologic changes support a non-DNA reactive mode of action for folpet carcinogenicity in mice involving the key events of mucosal cytotoxicity with consequent regenerative proliferation. Exposures that are not sufficient to produce cytotoxicity would also not lead to tumor formation.     

Antimicrobial activity of Hermannia incana

Hermannia incana Cav. (Sterculiaceae) is a prostrate herb used to treat stomachache and diarrhea, and as an emetic by the people of Eastern Cape Province, South Africa. Acetone, methanol, and water extracts from the leaves and roots of the plant were investigated for antibacterial and antimycotic activities. The methanol extracts of the plant showed appreciable activity against Gram-positive and Gram-negative bacteria at concentrations ranging from 0.5 to 7?mg/mL. The acetone and water extracts of both the leaves and the roots showed moderate activity against Gram-positive bacteria and less activity against Gram-negative bacteria. All the extracts inhibited the growth of the fungi Aspergillus flavus, Aspergillus niger, and Mucor hiemalis with growth inhibition based on MIC ranging from 54% to 96% at 0.1-?10?mg/mL. None of the extracts suppressed the growth of Candida albicans at the maximum concentration (10?mg/mL) tested. This study has pointed to the potential application of Hermannia incana as a bacteriocide and fungicide.     

水杨酰肼的合成工艺研究

采用均匀设计方法，按回归方程优化肼解水杨酸甲酯合成水杨酰肼的工艺条件，结果使合成产主从８６．４５％提高到９４．７４％。     

Widely used pesticides with previously unknown endocrine activity revealed as in vitro antiandrogens

Background

Evidence suggests that there is widespread decline in male reproductive health and that antiandrogenic pollutants may play a significant role. There is also a clear disparity between pesticide exposure and data on endocrine disruption, with most of the published literature focused on pesticides that are no longer registered for use in developed countries.

Objective

We used estimated human exposure data to select pesticides to test for antiandrogenic activity, focusing on highest use pesticides.

Methods

We used European databases to select 134 candidate pesticides based on highest exposure, followed by a filtering step according to known or predicted receptor-mediated antiandrogenic potency, based on a previously published quantitative structure–activity relationship (QSAR) model. In total, 37 pesticides were tested for in vitro androgen receptor (AR) antagonism. Of these, 14 were previously reported to be AR antagonists (“active”), 4 were predicted AR antagonists using the QSAR, 6 were predicted to not be AR antagonists (“inactive”), and 13 had unknown activity, which were “out of domain” and therefore could not be classified with the QSAR (“unknown”).

Results

All 14 pesticides with previous evidence of AR antagonism were confirmed as antiandrogenic in our assay, and 9 previously untested pesticides were identified as antiandrogenic (dimethomorph, fenhexamid, quinoxyfen, cyprodinil, λ-cyhalothrin, pyrimethanil, fludioxonil, azinphos-methyl, pirimiphos-methyl). In addition, we classified 7 compounds as androgenic.

Conclusions

Due to estimated antiandrogenic potency, current use, estimated exposure, and lack of previous data, we strongly recommend that dimethomorph, fludioxonil, fenhexamid, imazalil, ortho-phenylphenol, and pirimiphos-methyl be tested for antiandrogenic effects in vivo. The lack of human biomonitoring data for environmentally relevant pesticides presents a barrier to current risk assessment of pesticides on humans.