Organic amendments to enhance herbicide biodegradation in contaminated soils

Pesticide contamination of soil and groundwater at agricultural chemical distribution sites is a widespread problem in the USA. Alternatives to land-farming or solid waste disposal include biostimulation and phytoremediation. This research investigated the ability of compost, corn stalks, corn fermentation byproduct, peat, manure, and sawdust at rates of 0.5% and 5% (w/w) to stimulate biodegradation of atrazine [6-chloro-N-ethyl-N'-(1-methyethyl)-1,3,5-triazine-2,4-diamine], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], and trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine] added as a mixture to soil. Initial concentrations were 175ᆾ mg atrazine kg^-1 soil, 182ᆭ mg metolachlor kg^-1 soil, and 165ᆫ mg trifluralin kg^-1 soil. After amendment addition, 30% of the atrazine, 33% of the metolachlor, and 44% of the trifluralin was degraded over 245 days, which included 63 days' aging prior to amendment additions. Atrazine degradation was enhanced by 0.5% manure, 5% peat, and 5% cornstalk amendments compared to nonamended soils. Metolachlor degradation was enhanced by all amendments at the 5% level, except for compost and peat. Amendments had no effect on trifluralin degradation. The 5% addition of compost, manure, and cornstalks resulted in significant increases in bacterial populations and dehydrogenase activity. A second experiment compared the persistence of atrazine, metolachlor, and trifluralin applied in a mixture to their persistence in soil individually. A combined average of 123 mg atrazine kg^-1 remained in soil treated with the three-herbicide mixture compared to 31 mg atrazine kg^-1 remaining in soil treated with atrazine only. Atrazine mineralization and atrazine-degrading microorganisms were suppressed by high concentrations of metolachlor, but not by trifluralin.     

Effects of castration on chronic bacterial prostatitis in dogs

An Escherichia coli bacterial prostatitis was experimentally induced in dogs to determine the effect of castration on chronic bacterial prostatitis. Two weeks after instillation of bacteria directly into the prostate gland, 17 of 22 adult mixed-breed male dogs had positive urine or prostatic fluid cultures or both. Seven of the 17 dogs were randomly chosen to be castrated, and 10 of the 17 served as sham-operated controls. At weekly intervals, urine was obtained from 17 dogs for aerobic microbiologic culturing. At each week, dogs with no bacterial growth in the cultured urine had prostatic fluid collected for aerobic microbiologic culture. Dogs with negative urine, prostatic fluid, and prostatic tissue needle biopsy culture results at week 7 were euthanatized. For remaining dogs, weekly cultures were continued until the dogs were euthanatized at week 12. None of the 7 castrated dogs and 6 of the 10 dogs subject to sham operation had prostatic infection at the time of necropsy. The castrated dogs had a mean infection duration of 4.2 weeks, which was statistically shorter than the 9.5-week mean duration of infection in the sham-operated controls. Cultures of prostatic tissue obtained immediately after euthanasia correlated 100% with urine and prostatic fluid cultures taken before euthanasia. All of the 6 dogs with positive prostatic cultures at termination had moderate to marked lymphoplasmacytic chronic prostatitis. The 11 dogs that were not infected at the end of the study had normal to moderate lymphoplasmacytic chronic prostatitis on histologic examination.(ABSTRACT TRUNCATED AT 250 WORDS)     

Generalized demodicosis in a cat responsive to amitraz

Generalized demodicosis was diagnosed in a 14-year-old castrated male domestic short-hair cat. No underlying disease was detected. The cat responded incompletely or poorly to commonly recommended treatment, but responded well to total body dipping with 0.0125% amitraz at weekly intervals.     

Eradication of over-wintering mildew (Podosphaera leucotricha) in apple buds by nitrogen-containing surfactants

The eradicant activities of 24 nitrogen-containing preparations, comprising primary, secondary or tertiary amines, amine acetates, diamines, amine oxides or quaternary ammonium salts, were assessed in trials with potted dormant apple rootstocks, heavily infected with the powdery mildew fungus Podosphaera leucotricha. The surfactants consisted of mixtures in which C₁₂/C₁₄ or C₁₆/C₁₈ alkyl or alkenyl compounds predominated. Of the amine acetates (at 50g litre^?1), only the formulation containing C₁₂/C₁₄ primary amine acctates was considered worthy of further evaluation. Some amine oxides and quaternary ammonium compounds (at 35 g litre^?1) were good eradicants and were as effective as ‘PP222’ a (nonylphenol-ethoxylate mixture) which was included for comparison. All the compounds showing good activity contained one C₁₂/C₁₄ alkyl group whereas C₁₆/C₁₈ compounds, whether saturated or unsaturated, were relatively inactive. In a field trial, C₁₂/C₁₄ (dimethyl) amine oxide, C₁₂/C₁₄bis (2-hydroxyethyl) amine oxide, and C₁₂/C₁₄ amine acetate (35 g litre^?1) greatly reduced the amount of primary mildew on trees that were previously heavily infected, but there were signs that the fruit yield was reduced.     

Using 3D animations to teach intracellular signal transduction mechanisms: taking the arrows out of cells

Traditional methods of teaching intracellular biological processes and pathways use figures or flowcharts with the names of molecules linked with arrows. Many veterinary students, presented with such material, simply memorize the names or chemical structures of the molecules and are then likely to forget the material once the examination is completed. To address this problem, the authors designed, created, and field-tested new teaching media that incorporate realistic three-dimensional (3D) animations depicting the dynamic changes that occur in intracellular molecules during cellular activation. Testing found that veterinary students taught using traditional teaching media (e.g., lectures, handouts, textbooks) are proficient in memorizing the names and order of intracellular molecules but unable to appreciate the interactions between these elements or their spatial relationships within cells. In contrast, more than 90% of veterinary students taught using 3D animations not only recall the facts about the intracellular elements but also develop accurate mental images of the interactions among these molecules and their spatial relationships. These findings strongly suggest that the comprehension of complex biological processes by veterinary students can be enhanced by the use of dynamic 3D depictions of these processes in the classroom.