The effect of 2-benzylamino-1,3,5-triazines on photosynthetic electron transport (PET) was measured with thylakoids isolated from atrazine-resistant, wild-type Chenopodium album, and spinach to find novel 1,3,5-triazine herbicides bearing a strong PET inhibition. The PET inhibition assay with Chenopodium (wild-type and resistant), yielded a resistance ratio (R/W = I50 (resistant)/I50 (wild-type...

There is increasing concern that certain chemicals in the environment can cause endocrine disruption in exposed humans and wildlife. Investigations of potential effects on endocrine function have been limited mainly to interactions with hormone receptors. A need exists for the development of alternate in vitro methods to evaluate chemicals for their potential to disturb various endocrine functi...

Cyanobacterium Plectonema boryanum IU 594 and cyanophage LPP-1 were used as indicator organisms in a bioassay of 16 pesticides. Experiments such as spot tests, disk assays, growth curves, and one-step growth experiments were used to examine the effects of pesticides on the host and virus. Also, experiments were done in which host or virus was incubated in pesticide solutions and then assayed fo...

Hydroxyatrazine [2-(N-ethylamino)-4-hydroxy-6-(N-isopropylamino)-1,3,5-triazine] N-ethylaminohydrolase (AtzB) is the sole enzyme known to catalyze the hydrolytic conversion of hydroxyatrazine to N-isopropylammelide. AtzB, therefore, serves as the point of intersection of multiple s-triazine biodegradative pathways and is completely essential for microbial growth on s-triazine herbicides. Here, ...

Enrichment cultures utilizing deethylsimazine (6-chloro-N-ethyl-l,3,5-triazine-2,4-diamine) as a sole nitrogen source were obtained from so5 that had had long exposure to s-triazine herbicides. A bacterium was isolated that utilized deethylsimazine quantitatively as a nitrogen source for growth, but only 1 mol of nitrogen was obtained/mol of deethylsimazine, whereas all six atoms in melamine we...

Empore disks were used to successfully extract herbicide residues from a difficult-to-analyze surface water source and deionized water. Herbicide recoveries were lower in surface water at 7,14, or 21 days after fortification and storage at 4 degrees C, presumably due to chemical sorption onto precipitated organic particulates. The addition of acid to the samples, as recommended in EPA Method 52...

A simple, rapid, efficient, and environmentally friendly method for the determination of five triazine herbicides in water and soil samples was developed by using dispersive liquid-liquid microextraction (DLLME), coupled with high performance liquid chromatography-diode array detection (HPLC-DAD). The water samples were directly used for DLLME extraction. For soil samples, the target analytes w...

The effects of the photosystem II herbicides diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) on the photosynthetic membranes of a cyanobacterium, Aphanocapsa 6308, were compared to the effects on a higher plant, Spinacia oleracea. The inhibition of photosystem II electron transport by these herbicides was investigated by measurin...

Atrazine produces mammary gland cancer in one strain of rats and has been classified as an endocrine modulator. Epidemiologic studies have reported associations between agricultural use of atrazine and several forms of cancer. This study evaluated mortality patterns among workers at a plant that made atrazine and other triazine herbicides. The study covered the time period 1970-1997 and include...

Triazine herbicides inhibit photosynthesis by blocking electron transport in photosystem II. The target site of the herbicide was identified as a chloroplast thylakoid polypeptide (the Q B protein) o f 32,000 daltons. Studies o f triazine-resistant weed biotypes suggested that a subtle change in the QB protein caused the resistance. We have cloned the chloroplast gene (psbA) that codes this pro...