Viability and stability of biological control agents on cotton and snap bean seeds.

Cotton and snap bean were selected for a multi-year, multi-state regional (south-eastern USA) research project to evaluate the efficacy of both commercial and experimental bacterial and fungal biological control agents for the management of damping-off diseases. The goal for this portion of the project was to determine the viability and stability of biological agents after application to seed. The biological seed treatments used included: (1) Bacillaceae bacteria, (2) non-Bacillaceae bacteria, (3) the fungus Trichoderma and (4) the fungus Beauveria bassiana. Seed assays were conducted to evaluate the following application factors: short-term (< or = 3 months) stability after seed treatment; quality (i.e. isolate purity); compatibility with chemical pesticides and other biocontrol agents; application uniformity between years and plant species. For the bacterial treatments, the Bacillaceae genera (Bacillus and Paenibacillus) maintained the greatest population of bacteria per seed, the best viability over time and the best application uniformity across years and seed type. The non-Bacillaceae genera Burkholderia and Pseudomonas had the least viability and uniformity. Although Beauveria bassiana was only evaluated one year, the seed fungal populations were high and uniform. The seed fungal populations and uniformity for the Trichoderma isolates were more variable, except for the commercial product T-22. However, this product was contaminated with a Streptomyces isolate in both the years that it was evaluated. The study demonstrated that Bacillaceae can be mixed with Trichoderma isolates or with numerous pesticides to provide an integrated pest control/growth enhancement package.

Beneficial Effects of Solid Matrix Chemo-priming in Okra.

Two field trials at Stillwater and Bixby, OK, evaluated the efficacy of solid matrix priming techniques, alone or in combination with fungicide seed treatment on seedling emergence and reduction of damping-off of okra in field soil naturally infested with Pythium ultimum. The following treatments were evaluated: thiram + carboxin (chemo-primed) (commercially applied), biological seed treatment (bio-primed) (Trichoderma harzianum isolate OK-110, 1 g suspended in 1% carboxymethylcellulose [CMC]), untreated seed (control), and a 1% CMC control. Chemo-primed seeds had a more uniform and faster emergence compared with untreated seeds at both field sites. Within 3 days, 92 and 78% of chemo-primed seeds had emerged at Stillwater and Bixby, respectively, compared with 84 and 71% emergence in the untreated control. Mean emergence of chemo-primed seeds was lower (P ≤ 0.05) than the untreated control. Chemo-primed seeds had greater vigor (P≤ 0.05) at both locations compared with either fungicide-treated or priming alone, at both locations. There were no differences (P ≤ 0.05) in yield among treatments at both locations. P. ultimum was consistently isolated from damped-off seedlings and surrounding soil at both locations. Isolates of P. ultimum were more pathogenic on okra in laboratory tests than isolates of Rhizoctonia spp., Fusarium spp., and other Pythium spp. also isolated from seed or soil.

TMS1, a novel proapoptotic caspase recruitment domain protein, is a target of methylation-induced gene silencing in human breast cancers.

Gene silencing associated with aberrant methylation of promoter region CpG islands is an acquired epigenetic alteration that serves as an alternative to genetic defects in the inactivation of tumor suppressor and other genes in human cancers. The hypothesis that aberrant methylation plays a direct causal role in carcinogenesis hinges on the question of whether aberrant methylation is sufficient to drive gene silencing. To identify downstream targets of methylation-induced gene silencing, we used a human cell model in which aberrant CpG island methylation is induced by ectopic expression of DNA methyltransferase. Here we report the isolation and characterization of TMS1 (target of methylation-induced silencing), a novel CpG island-associated gene that becomes hypermethylated and silenced in cells overexpressing DNA cytosine-5-methyltransferase-1. We also show that TMS1 is aberrantly methylated and silenced in human breast cancer cells. Forty percent (11 of 27) of primary breast tumors exhibited aberrant methylation of TMS1. TMS1 is localized to chromosome 16p11.2-12.1 and encodes a 22-kDa predicted protein containing a COOH-terminal caspase recruitment domain, a recently described protein interaction motif found in apoptotic signaling molecules. Ectopic expression of TMS1 induced apoptosis in 293 cells and inhibited the survival of human breast cancer cells. The data suggest that methylation-mediated silencing of TMS1 confers a survival advantage by allowing cells to escape from apoptosis, supporting a new role for aberrant methylation in breast tumorigenesis.

Integration of Biological and Chemical Controls for Rhizoctonia Aerial Blight and Root Rot of Rosemary.

Aerial blight, caused by Rhizoctonia solani AG-4, was identified as a major disease of greenhouse mist-produced rosemary cuttings. An isolate of the biocontrol fungus Laetisaria arvalis, selected for tolerance to the experimental fungicide CGA 173506, was used as an amendment to potting soil. Combined treatment of rosemary with L. arvalis and a foliar spray of the fungicide at one-half the recommended rate reduced disease more than treatment with either the fungus or fungicide alone. Similar synergism was not observed for combinations of Trichoderma harzianum as a soil amendment and a foliar spray of the fungicide iprodione applied at the labeled rate.

Characterization of pXV10A, a Copper Resistance Plasmid in Xanthomonas campestris pv. vesicatoria.

The efficacy of copper bactericides for control of Xanthomonas campestris pv. vesicatoria in eastern Oklahoma tomato fields was evaluated. Copper bactericides did not provide adequate control, and copper-resistant (Cu) strains of the pathogen were isolated. The Cu genes in these strains were located on a large indigenous plasmid designated pXV10A. The host range of pXV10A was investigated; this plasmid was efficiently transferred into 8 of 11 X. campestris pathovars. However, the transfer of pXV10A to other phytopathogenic genera was not detected. DNA hybridization experiments were performed to characterize the Cu genes on pXV10A. A probe containing subcloned Cu genes from X. campestris pv. vesicatoria E3C5 hybridized to pXV10A; however, a subclone containing Cu genes from P. syringae pv. tomato PT23 failed to hybridize to pXV10A. Further DNA hybridization experiments were performed to compare pXV10A with pXvCu plasmids, a heterogenous group of Cu plasmids present in strains of X. campestris pv. vesicatoria from Florida. These studies indicated that the Cu genes on pXV10A and pXvCu plasmids share nucleotide sequence homology and may have a common origin. Further experiments showed that these plasmids are distinctly different because pXV10A did not contain sequences homologous to IS476, an insertion sequence present on pXvCu plasmids.

Effects of exercise at high altitudes on young adults.

Outward Bound programs are carried out throughout the world, and many of these courses occur at altitudes above 3000 m (10,000 ft). As more knowledge is accumulated about health problems at high altitudes, exercise has been implicated as a factor contributing to acute mountain sickness in susceptible individuals. Thus, exercise conditioning programs occurring at high altitudes have come under scrutiny. Twenty-eight young men and women were enrolled in an Outward Bound course at an altitude over 3000 m for a 21-day period. Twelve of the 28 individuals developed shortness of breath, cough, or both by the third day of the course. Of these 12, seven had pulmonary function abnormalities: three having evidence of large airway involvement and four having findings of small airway involvement. The symptoms were not significant enough to interfere with acclimatization and the muscular conditioning aspects of the program. Although at altitudes between 3000 m and 4300 m, pulmonary function abnormalities of acute mountain sickness develop in a significant number of participants, the abnormalities were not significant enough to prevent persons from completing the course or achieving marked improvements in fitness measurements.