Effects of Spent Mushroom Compost (SMC) as an Ingredient in Phase I Compost on Production of Agaricus bisporus

Experiments were performed to determine the effect of using 20% spent mushroom compost (SMC) as an ingredient in phase I compost on mushroom yield. Yields from compost prepared with two 20% SMC formulations (80Ctl, 80LC) were compared to a standard control (Ctl) containing no SMC. The 80LC compost was formulated with a higher level of lignocellulose raw materials, including corn stover, corncobs, cottonseed hulls, and wheat straw. The 80Ctl compost contained 20% SMC plus the same raw materials used to prepare Ctl compost. Yields of 80LC matched or exceeded yields of the Ctl compost in all three crops while yields of 80Ctl were significantly lower. As an additional factor, lignocellulose supplements were added at spawning and were a significant factor in increasing mushroom yields, although not superior to a standard commercial supplement applied at 3.7% (dry compost weight). Compost bulk density was significantly higher (19–20%) in compost formulations containing 20% SMC compared to the non-SMC Ctl. Populations of four prominent phyla of bacteria (Firmicutes, Actinobacteria, Proteobacteria, and Chloroflexi), as determined by pyrosequence analysis, were similar in both compost types and did not appear to influence mushroom yield.     

Experiences with a vaccine being developed for the control of swine dysentery

SUMMARY A prototype vaccine that is being developed for the control of swine dysentery (SD) was tested in two groups of experimental pigs. Vaccination induced high circulating antibody titres against the aetiological agent, Serpulina (Treponema) hyodysenteriae .
Pigs in the first trial were vaccinated twice before being challenged orally with the bacteria. Five of 6 unvaccinated animals developed dysentery within a fortnight of challenge, but only 1 of 6 vaccinated pigs showed signs of disease at this time. Unexpectedly, 1 mo after challenge, the surviving unvaccinated pig and 2 remaining healthy vaccinated animals succumbed to the disease. The reason for the development of this late-onset form of dysentery was not clear.
In the second trial, 8 pigs were vaccinated 3 times. Only 2 of these animals (25%) developed severe dysentery after being mixed with infected pigs, whereas 7 of 8 (88%) unvaccinated control pigs in the same pen became diseased. The late-onset form of dysentery was not observed.
The prototype vaccine for SD provided a useful level of protection, and could be used in programs to control the disease in Australia.     

Antimicrobial susceptibility testing of Serpulina hyodysenteriae

Summary The macrobroth dilution technique was used to test the in-vitro effectiveness of 4 commonly used antimicrobial agents against 23 Australian isolates and 7 overseas strains of Serpulina hyodysenteriae. Minimum inhibitory concentrations and minimum bactericidal concentrations were determined. The growth of 90% of isolates was inhibited by dimetridazole at a concentration of 4 μg/mL, and by tiamulin at 8 μg/mL Australian isolates resistant to both antimicrobial agents were identified. Lincomycin was less effective than these antimicrobial agents, with 90% of isolates requiring a concentration of 128 μg/mL for inhibition of growth, and 54% being susceptible at 64 μg/mL. Tylosin did not prevent the growth of the majority of S hyodysenteriae isolates tested, and 90% were resistant to concentrations of 128 μg/mL. Resistant isolates came from different geographical areas. Resistance was not related to overall genetic background of the spirochaetes, and was not correlated with the presence of plasmids or the serogroup of the isolates.     

Vitrification of In Vitro-produced Bovine Embryos by Addition of Ethylene Glycol in One-step

The objective of this study was to simplify two-step addition of cryoprotectant for vitrification of bovine embryos by developing a one-step procedure. Survival was calculated as a percentage of non-vitrified controls developed from the same batch of oocytes. In experiment 1, bovine blastocysts were vitrified following one- or two-step addition of cryoprotectant. Exposure of embryos to cryoprotectant in one-step resulted in survival rates not significantly lower (p > 0.1) than those obtained by two-step addition (85% vs 98%, respectively). Based on these results, experiments 2-4 were designed to test one-step addition of cryoprotectant more rigorously. Experiment 2 exposed day 7 blastocysts to 6, 7 or 8 M ethylene glycol for 2.5 or 3.5 min. At 24 h post-vitrification, survival of embryos was similar, irrespective of ethylene glycol concentration or exposure time (6 M 38%, 7 M 51%, 8 M 59%; 2.5 min 54%, 3.5 min 45%). In experiment 3, blastocysts were exposed to 7 M ethylene glycol for shorter times (30 or 60 s); 30 s exposure resulted in decreased survival (8% vs 31%, p < 0.05). Experiment 4 concerned one-step addition of cryoprotectant to day 6 bovine morulae, exposed to 7 M ethylene glycol for 1 or 1.5 min. There was no difference in survival between exposure times of 1 or 1.5 min (28% vs 45%, respectively; p > 0.1). It is unclear why many embryos survive vitrification with one-step addition of cryoprotectant, but others do not. Although, one-step addition of cryoprotectant simplifies the vitrification procedure, survival rates were inadequate for routine cryopreservation of in vitro-produced bovine embryos.     

Cultivation of <Emphasis Type="Italic">Pleurotus eryngii</Emphasis> on umbrella plant (<Emphasis Type="Italic">Cyperus alternifolius</Emphasis>) substrate

Mycelial growth and mushroom yields of three strains of Pleurotus eryngii produced on wheat bran-supplemented umbrella plant (Cyperus alternifolius) substrate were assessed using surface brightness, bromophenol blue color reactions, ergosterol and glucosamine contents, and water potential as indicators of strain performance. Mycelial growth was 31%–46% greater, depending on strain, on the umbrella plant substrate compared with the mushroom industry standard sugi (Cryptomeria japonica) substrate. Mushroom yields on the first flush were 20%–23% higher, depending on strain, on the plastic bottle-contained umbrella plant substrate. However, yields on the second break were lower from the umbrella plant substrate. Because many growers in Japan only harvest one flush, production of P. eryngii on umbrella plant substrate may offer commercial producers an alternative basal ingredient to diminishing supplies of sugi sawdust.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002.     

Elasticity of single-crystal MgO to 8 gigapascals and 1600 kelvin

The cross pressure (P) and temperature (T) dependence of the elastic moduli (Cij) of single-crystal samples of periclase (MgO) from acoustic wave travel times was measured with ultrasonic interferometry: partial differential2C11/ partial differentialP partial differentialT = (-1.3 +/- 0.4) x 10(-3) per kelvin; partial differential2C110/ partial differentialP partial differentialT = (1. 7 +/- 0.7) x 10(-3) per kelvin; and partial differential2C44/ partial differentialP partial differentialT = (-0.2 +/- 0.3) x 10(-3) per kelvin. The elastic anisotropy of MgO decreases with increasing pressure at ambient temperature, but then increases as temperature is increased at high pressure. An assumption of zero cross pressure and temperature derivatives for the elastic moduli underestimates the elastic anisotropy and overestimates the acoustic velocities of MgO at the extrapolated high-pressure and high-temperature conditions of Earth's mantle.