Survey of vomitoxin-contaminated feed grains in midwestern United States, and associated health problems in swine

During the 1981 corn harvest season in Illinois and surrounding states, cold wet weather enhanced the growth of Fusarium graminearum, with resulting contamination by vomitoxin and, to a lesser extent, zearalenone. Of 342 feed samples analyzed, 274 contained vomitoxin at a concentration ranging from 0.1 to 41.6 ppm (mean, 3.1 ppm) and 40 samples contained zearalenone at a concentration ranging from 0.1 to 8 ppm (mean, 0.66 ppm). Animal health problems and reduced growth performance were observed mainly in swine fed vomitoxin-contaminated rations. The predominant clinical complaints, in decreasing frequency were: reproductive problems (50%), feed refusal (43%), reduced weight gain (25%), diarrhea (17%), death (14%), and emesis (11%).     

Pharmacokinetics of diacetoxyscirpenol in cattle and swine: effects of halothane

In swine and cattle given 0, 0.1, or 0.5 and 0, 0.5 mg of diacetoxyscirpenol (DAS)/kg of body weight, IV, respectively; DAS had a large volume of distribution and total body clearance. The shortness of the interval between halothane and DAS exposures significantly (P greater than 0.05) decreased DAS biotransformation. Urinary excretion of DAS as a parent compound was not an important route of elimination. In swine and cattle, DAS was transformed by sequential deacetylation to monoacetoxyscirpenol and scirpentriol.     

Combinations of Fungicides with Phylloplane Yeasts for Improved Control of Botrytis cinerea on Geranium Seedlings

ABSTRACT Control of Botrytis cinerea on geranium seedlings was evaluated in treatments with phylloplane yeasts in combination with 10 fungicides used to manage Botrytis blight of ornamental plants. Rhodotorula glutinis PM4 significantly reduced the development of lesions caused by B. cinerea on geranium cotyledons; however, yeast biocontrol efficacy was highly variable between trials. Treatment with the yeast in combination with azoxystrobin or trifloxystrobin at one tenth the labeled rate (7.5 mug a.i. ml(-1)) or the full labeled rate (7.5 mug a.i. ml(-1)) reduced lesion development, compared to treatment with the yeast or the fungicide alone. Vinclozolin at half the labeled rate or the full labeled rate (250 or 500 mug a.i. ml(-1)), in combination with R. glutinis PM4, significantly reduced the development of lesions caused by an isolate of B. cinerea resistant to vinclozolin. Copper hydroxide and iprodione at one-tenth the labeled rates, with or without yeast, were highly effective in limiting lesion development. Mancozeb did not increase the biocontrol efficacy of the yeast, and thiophanate-methyl negatively affected the yeast efficacy. Improved disease control was observed in treatments with vinclozolin at the labeled rate and R. glutinis PM4 at cell densities of 5 x 10(5) and 1 x 10(6) cells ml(-1), but not 1 x 10(5) cells ml(-1), on seedlings co-inoculated with B. cinerea in a suspension containing 1 x 10(5) conidia ml(-1). Disease control improved in treatments with combinations of vinclozolin and eight other isolates of R. glutinis, two isolates of R. graminis, and two isolates of R. mucilaginosa. Biocontrol was not observed in treatments with two isolates of R. minuta. The combination of yeast and vinclozolin significantly reduced the germination of conidia of B. cinerea and the growth of R. glutinis PM4 in vitro. All combinations of R. glutinis PM4 with azoxystrobin, trifloxystrobin, or vinclozolin provided highly effective and consistent disease control not observed in treatments with the fungicides alone or the yeast alone.     

Rapid identification of bovine mastitis pathogens by high-resolution melt analysis of 16S rDNA sequences

Accurate identification of mastitis pathogens is often compromised when using conventional culture-based methods. Here, we report a novel, rapid assay tested for speciation of bacterial mastitis pathogens using high-resolution melt analysis (HRMA) of 16S rDNA sequences. Real-time PCR amplification of 16S rRNA gene fragment, spanning the variable region V5 and V6 was performed with a resulting amplicon of 290bp. First, a library was generated of melt curves of 9 common pathogens that are implicated in bovine mastitis. Six of the isolates, Escherichia coli, Streptococcus agalactiae, Klebsiella pneumoniae, Streptococcus uberis, Staphylococcus aureus and Mycoplasma bovis, were type strains while the other 3, Arcanobacterium pyogenes, Corynebacterium bovis and Streptococcus dysgalactiae, were bovine mastitis field isolates. Four of the type strains, E. coli, S. agalactiae, K. pneumoniae and S. aureus, were found to be of human origin, while the other 3 type strains were isolated from bovine infections. Secondly, the melt curves and corresponding amplicon sequences of A. pyogenes, E. coli, S. agalactiae, S. dysgalactiae, K. pneumoniae, S. uberis and S. aureus were compared with 10 bovine mastitis field isolates of each pathogen. Based on the distinct differences in melt curves and sequences between human and bovine isolates of E. coli and K. pneumoniae, it was deemed necessary to select a set of bovine strains for these pathogens to be used as reference strains in the HRMA. Next, the HRMA was validated by three interpreters analyzing the differential clustering pattern of melt curves of 60 bacterial cultures obtained from mastitis milk samples. The three test interpreters were blinded to the culture and sequencing results of the isolates. Overall accuracy of the validation assay was 95% as there was difficulty in identifying the streptococci due to heterogeneity observed in the PCR amplicons of S. uberis. The present study revealed that broad-range real-time PCR with HRMA can be used as a powerful, fast and low-cost tool for the differentiation of clinically important bacterial mastitis pathogens.     

Polygenetic development of the Mormon Mesa,NV petrocalcic horizons: Geomorphic and paleoenvironmental interpretations

Mormon Mesa, Nevada, USA is of one of Earth's rare and unique landforms. Regionally, Mormon Mesa is important because of its relationship to the lower Colorado River and its connection to stream incision. Petrocalcic horizons at Mormon Mesa developed from multiple exposure, erosion, and sedimentation events driven by variations in paleoclimate since the early Pliocene. This study utilizes pedogenic features at Mormon Mesa to construct a sequence of development for the soil profile. We sampled and described seven profiles at Mormon Mesa to determine the soil and geomorphic processes that have influenced the development of this geomorphically important soil. The Mormon Mesa soil profile generally consists of four petrocalcic soil horizons from the base upward (transitional, laminar, massive, and brecciated) and an additional set of horizons that formed in unconsolidated surficial eolian sediments. The transitional horizon formed after cessation of Muddy Creek Fm. deposition (~ 5 to 4 Ma) and accumulated calcium carbonate to a stage II–III morphology (maybe IV in some locations). After a period of landform stability, the upper portion of the transitional horizon was exposed and eroded (~ 2.8 Ma). Petrocalcic fragments and stage II pendants that formed in the transitional horizon were exposed on the surface and later mixed with aggrading eolian sediments. After the surface re-stabilized, calcium carbonate accumulated along the underlying discontinuity with the transitional horizon and formed a laminar horizon. Shallower accumulations of calcium carbonate formed pendants on the undersides of the rotated petrocalcic fragments and pendants that had previously been eroded from the transitional horizon. Continued rooting and bioturbation caused rotation and multiple directions of pendant formation. Today, in plan view, these pendants appear concentric and are the pisoliths described by Bachman and Machette [Bachman, G.O., Machette, M.N., 1977. Calcic Soils and Calcretes in the Southwestern United States., USGS: Open-File Report 77–797]. Continued calcium carbonate precipitation eventually plugged the horizon (massive horizon). After the massive horizon became indurated, the upper portion was exposed, fractured, eroded, and mixed with aggrading eolian sediments. These brecciated fragments experienced erosion/brecciation and soil stabilization/cementation with pedogenic calcite multiple times, probably as a result of the Pleistocene glacial/interglacial climate cycles. All of the features described in this study are interpreted to have formed in response to climatic changes that caused either soil erosion with concurrent eolian deposition, or soil development and pedogenic carbonate accumulation.