Early harvest and ensilage of forage sorghum infected with ergot (Claviceps africana) reduces the risk of livestock poisoning

Sorghum ergot produces dihydroergosine (DHES) and related alkaloids, which cause hyperthermia in cattle. Proportions of infected panicles (grain heads), leaves and stems were determined in two forage sorghum crops extensively infected 2 to 4 weeks prior to sampling and the panicles were assayed for DHES. Composite samples from each crop, plus a third grain variety crop, were coarsely chopped and half of each sealed in plastic buckets for 6 weeks to simulate ensilation. The worst-infected panicles contained up to 55 mg DHES/kg, but dilution reduced average concentrations of DHES in crops to approximately 1 mg/kg, a relatively safe level for cattle. Ensilation significantly (P = 0.043) reduced mean DHES concentrations from 0.85 to 0.46 mg/kg.     

Presence of encysted immature nematodes in a released whooping crane (Grus americana).

Numerous nematode cysts were observed throughout the mesentery and on the surface of gastrointestinal organs in a whooping crane (Grus americana) that was found dead in a central Florida marsh. Morphology of the excysted nematodes most closely resembled third-stage larvae in the order Spirurida but were not similar to any species previously reported in whooping cranes. Evidence presented suggests that the larvae may be Physocephalus sexalatus, a swine spirurid in the subfamily Ascaropsinae that is commonly found encapsulated in birds, amphibians, and reptiles. We suspect that the whooping crane may potentially serve as a transport host for this parasite.     

The effect of biocidal treatments on respiration and enzymatic activities of douglas-fir needle litter

Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) needle-litter was given treatments of varying biocidal severity including air-drying, oven-drying, fumigation with methyl bromide plus chloropicrin. autoclaving, and a control. The litter was inoculated with a small amount of fresh litter homogenate and monitored for CO₂ evolution rate and extractable enzymatic activity during a 77-day incubation. Enzymatic activities assayed included cellulase. xylanase, mannase, amylase. invertase, β-glucosidase, protease, polyphenoloxidase and peroxidase. The concentrations of extractable ninhydrin-reactive compounds, glucose, and reducing substances were also determined.

Air-drying produced a small, initial stimulation in respiration but had no effect on any enzymatic activity throughout the 77-day incubation except for an initial decrease in polyphenoloxidase and peroxidase activities. Oven-drying produced a substantial loss of all enzymatic activities initially but all carbohydrase and protease activities recovered to greater than control levels by 7 days; after a 1-day lag, oven-drying produced a pronounced stimulation in the rate of CO₂ evolution. Autoclaving produced a 2-day lag in a less pronounced (compared to oven-drying) respiratory stimulation: initially all enzymatic activities were destroyed and only protease and β-glucosidase activities recovered to control levels. Fumigation produced a respiratory stimulation after a 9-day lag (probably due to residual chloropicrin) which coincided with a pronounced increase in cellulase. xylanase, mannase and amylase activities: initially, no activities except polyphenoloxidase and peroxidase were adversely affected by fumigation.

During the entire incubation, the activities of cellulase. xylanase. mannase. amylase and invertase were highly correlated with each other regardless of treatment. After 77 days, the rates of CO₂ evolution of all samples were correlated with the level of amylase and cellulase activity (r = 0.86 and 0.83, respectively). This observation points to the value of enzymatic assays for following the processes which release substrate for microbial assimilation from plant litter. The close association of polysaccharidase and protease activities with the flush of CO₂ evolution following biocidal treatment, particularly oven-drying, indicates that the decomposition of carbohydrates and proteins released from microbial biomass or plant litter is a mechanism for this often-observed respiratory stimulation.     

The fall, recovery, orbit, and composition of the Tagish Lake meteorite: a new type of carbonaceous chondrite

The preatmospheric mass of the Tagish Lake meteoroid was about 200,000 kilograms. Its calculated orbit indicates affinity to the Apollo asteroids with a semimajor axis in the middle of the asteroid belt, consistent with a linkage to low-albedo C, D, and P type asteroids. The mineralogy, oxygen isotope, and bulk chemical composition of recovered samples of the Tagish Lake meteorite are intermediate between CM and CI meteorites. These data suggest that the Tagish Lake meteorite may be one of the most primitive solar system materials yet studied.