Effect of sulfonylurea tribenuron methyl herbicide on soil Actinobacteria growth and characterization of resistant strains

ABSTRACT Repeated application of pesticides disturbs microbial communities and cause dysfunctions on soil biological processes. Granstar® 75 DF is one of the most used sulfonylurea herbicides on cereal crops; it contains 75% of tribenuron-methyl. Assessing the changes on soil microbiota, particularly on the most abundant bacterial groups, will be a useful approach to determine the impact of Granstar® herbicide. For this purpose, we analyzed Actinobacteria, which are known for their diversity, abundance, and aptitude to resist to xenobiotic substances. Using a selective medium for Actinobacteria, 42 strains were isolated from both untreated and Granstar® treated soils. The number of isolates recovered from the treated agricultural soil was fewer than that isolated from the corresponding untreated soil, suggesting a negative effect of Granstar® herbicide on Actinobacteria community. Even so, the number of strains isolated from untreated and treated forest soil was quite similar. Among the isolates, resistant strains, tolerating high doses of Granstar® ranging from 0.3 to 0.6% (v/v), were obtained. The two most resistant strains (SRK12 and SRK17) were isolated from treated soils showing the importance of prior exposure to herbicides for bacterial adaptation. SRK12 and SRK17 strains showed different morphological features. The phylogenetic analysis, based on 16S rRNA gene sequencing, clustered the SRK12 strain with four Streptomyces type strains (S. vinaceusdrappus, S. mutabilis, S. ghanaensis and S. enissocaesilis), while SRK17 strain was closely related to Streptomyces africanus. Both strains were unable to grow on tribenuron methyl as unique source of carbon, despite its advanced dissipation. On the other hand, when glucose was added to tribenuron methyl, the bacterial development was evident with even an improvement of the tribenuron methyl degradation. In all cases, as tribenuron methyl disappeared, two compounds were detected with increased concentrations. These by-products appeared to be persistent and were not degraded either chemically or by the studied strains. Based on these observations, we suggested that bacterial activity on carbon substrates could be directly involved in the partial breakdown of tribenuron methyl, by generating the required acidity for the first step of the hydrolysis. Such a process would be interesting to consider in bioremediation of neutral and alkaline tribenuron methyl-polluted soils.

Effects of suplatast tosilate on airway inflammation and interleukin-5 in asthmatic rats / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effects of suplatast tosilate (IPD) on the airway inflammation and expression of interleukin-5 in asthmatic rats.</p><p><b>METHODS</b>Fifty adult male Sprague-Dawley rats (4-week- old) were randomly assigned to five groups: placebo control, untreated asthma, budesonide(BUD)-treated asthma , early or late IPD intervention group (n=10 rats each). Asthmatic mode was prepared by ovalbumin sensitizion and challenge. Inflammatory cells and the percentage of EOS were detected in bronchoalveolar lavage fluid (BALF). The lung tissues were removed to detect the lung histomorphology. Gene expression of IL-5 was measured by reverse transcription-polymerase chain reaction (RT-PCR). Levels of interleukin 5 (IL-5) in BALF were measured using ELISA.</p><p><b>RESULTS</b>The inflammatory cells and the percentage of EOS in BALF, IL-5 levels in BALF and IL-5 mRNA expression in the lung tissues were obviously higher in the untreated asthma group than the control group (P<0.05), while the parameters in the IPD or BUD-treated asthma groups were significantly lower than the untreated asthma group (P<0.05).</p><p><b>CONCLUSIONS</b>IPD treatment can alleviate airway inflammation in asthmatic rats, possibly through inhibiting IL-5 mRNA transcripts.</p>

use of hen's egg test -chorioallantoic membrane as a model to evaluate the potential eye irritation of herbicide [Tribenuron-Methyl]

The aim of the present study was to evaluate the potential eye irritation of herbicide [tribenuron-methyl] at concentrations [0.01%, 0.02% and 0.03%, w/v] by using the Hen's Egg Test -Chorioallantoic membrane test [HET-CAM] test. According to the our results tribenuron-methyl was classified as non-irritant to eye at concentration [0.01%, w/v] that is recommend by manufacture of herbicide because its doesn't induced any visible changes in the chorioallantoic vessel like [Hyperemia, Hemorrhage, Clotting] thus, the total scores of irritation were [0]. As well as, the increasing concentrations of herbicide at [0.02%, 0.03%, w/v] doesn't induced any vascular injury in [CAM]. In contrast, the N 0.1 NaOH [Positive control] was classified as strongly irritant because its was induced intense hemorrhage with opaque on [CAM] thus, the total scores of irritation were increased to [14]. Physiological saline [0.9% NaCl] [Negative control] doesn't induced any irritant effects in the chorioallantoic vessel thus; the total scores of irritation were [0] and classified as non - irritant for eye. We conclude that, the [HET-CAM] test has been shown to be most suitable for use as a model for evaluating the potential eye irritation of herbicide due to its sensitivity, rapidity and inexpensive as well as reduces the requirement for laboratory animals

A Report for the Research about the Accuracy of a flow Regulator

PURPOSE: The supply of fluids is a major consideration in modern medicine. When fluid is needed, flow regulators are extensively used. But no research or study of flow regulators has yet been performed in Korea. We researched the accuracy of flow regulators that are commonly used in domestic medicine. METHODS: We collected and studied the fluid pumped for an hour through four kinds of flow regulators that are used domestic ally. Infusion rates were 10, 20, 30, 40, 60, 80, 100, 150, and 200 ml/hr. For each rate, the height of the fluid between the point of infusion and the outlet was evaluated in 10 cm increments within the range 30 cm to 120 cm. RESULTS: Among the four products tested, one product injected the fluid three times at the standard height of 80~100 cm, an error of <10%. Two other products injected within the standard range once each, and the fourth product failed to inject within range even once. CONCLUSION: The accuracy of flow regulators in the domestic market was exceedingly low.

Laboratory simulated dissipation of metsulfuron methyl and chlorimuron ethyl in soils and their residual fate in rice, wheat and soybean at harvest / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Two sulfonylurea herbicides, metsulfuron methyl (Ally 20 WP) and chlorimuron ethyl (Classic 25 WP) were evaluated for their dissipation behaviour in alluvial, coastal saline and laterite soils under laboratory incubated condition at 60% water holding capacity of soils and 30 degrees C temperature was maintained. In field study herbicides were applied twice for the control of grasses, annual and perennials broad leaves weeds and sedges in rice, wheat and soybean to find out the residual fate of both the herbicides on different matrices of respective crops after harvest. Extraction and clean up methodologies for the herbicides were standardized and subsequently analyzed by HPLC. The study revealed that the half-lives of metsulfuron methyl and chlorimuron ethyl ranged from 10.75 to 13.94 d irrespective of soils and doses applied. Field trials with rice, wheat and soybean also revealed that these two herbicides could safely be recommended for application as no residues were detected in the harvest samples.

Determination of chlorimuron and metsulfuron residues in two soils of Argentina using a rapid seed-bioassay.

The presence of chlorimuron ethyl and metsulfuron methyl in two soils was determined by a modified petri dish bioassay. Pregerminated seeds of maize and sunflower were placed in petri dishes containing 85 to 100 g of treated soil. Radicle root lengths were measured after 24 h. Chlorimuron had no effect on maize on the Balcarce soil, however 0.007 microg g(-1) decreased sunflower root length. Chlorimuron decreased maize and sunflower root length regardless application dose on the San Cayetano soil. Metsulfuron decreased maize root length at 0.04 microg g(-1) and sunflower at 0.021 microg g(-1) on the Balcarce soil. On the San Cayetano soil metsulfuron at 0.001 microg g(-1) decreased maize and sunflower root length. The phytotoxicity of chlorimuron and metsulfuron changed according to soil type and dose. Maize and sunflower were 1.3-1.5 and 1.3-1.8 times respectively more sensitive to chlorimuron on the San Cayetano soil than on the Balcarce soil. In the case of metsulfuron, maize was similarly sensitive on both soils but sunflower was 1.7-2.0 times more sensitive on the San Cayetano soil than on the Balcarce soil. Phytotoxicity increased as organic matter (OM) content decreased and/or when the soil pH and concentration increased.