Phytotoxins from anaerobically decomposing wheat straw

Phytotoxicity was demonstrated in the aqueous extract of wheat (Triticum aestivum, L.) straw suspensions. When extracts were incubated under anaerobic conditions, the development of phytotoxicity was greater at 20°C than at 10°C. The toxic products formed during incubation depended upon the incubation medium. Acetic and butyric acids were the major toxins produced in liquid straw fermentations during the first 2 weeks. However, after that time the acids did not account for the total toxicity, suggesting formation of unidentified phytotoxins. Acetic, propionic and butyric acids were the toxins formed in sand culture. The development and accumulation of phytotoxins were favored where the sand-straw mixtures were water-saturated. The implications of these findings to wheat cultural practice is discussed.     

Aquatic turtles of Amazonia: An endangered resource

Turtles have long served man as an important food resource in Amazonia. During the colonial period, Portuguese traders disturbed nesting beaches on a large scale in search of eggs which were converted into oil for cooking and lighting. Exploitation was increasingly intense by the end of the 19th century and turtle populations had declined drastically. Although legislation has been passed to protect them, enforcement is lax and turtles face increasing pressure from man not only for food but as a result of habitat disturbance.     

The Prince Edward Islands: A sanctuary for seabirds in the Southern Ocean

This paper reviews the breeding distribution and numerical status of selected species of seabirds at 23 oceanic island groups in the Southern Ocean (between latitudes 35 and 70°S), based on census data and population estimates which have become available through increased scientific endeavour in the region during the last 15 years or so. The paper focuses on the avifauna of the Prince Edward islands, in the southern Indian Ocean, and points to the importance of these islands as a breeding station and sanctuary for seabirds. Only one oceanic island group, the Crozets, contains more species of breeding seabirds than the Prince Edward islands. Substantial segements (about 10% and greater) of the world breeding populations of the king and macaroni penguins, and the wandering, grey-headed, yellow-nosed and sooty albatrosses are based at the Prince Edward group. We recommend that Prince Edward Island (sensu stricto) should be a wilderness area, and that development at Marion Island should be kept to an absolute minimum.     

Analysis of fat-soluble vitamins. XXIII. High performance liquid chromatographic assay for vitamin D in vitamin D3 and multivitamin preparations.

Vitamin D is determined in preparations containing other fat-soluble vitamins by high performance liquid chromatography (HPLC). The unsaponifiable residue is extracted and separated from interferences by reverse phase chromatography; the fraction corresponding to vitamin D3 is collected and quantitated using normal phase chromatography (amylalcohol-n-hexane as mobile phase) by measuring the vitamin D3 and pre-vitamin D3 peaks at 254 nm. Previtamin D3 content is calculated as vitamin D3 with a conversion factor (determined on the equipment used). Application of the method to vitamin AD3 mixtures in oils gives 98-102% recovery. The reproducibility, using an external standard, is 2-3%, calculated as the coefficient of variation; with an internal standard, the coefficient of variation is 1-1.5%. The method measures potential vitamin D3 content in preparations containing greater than or equal to 200 IU/g in the presence of all known vitamin D3 isomers, vitamin A, and vitamin E.     

Spectrophotometric analysis of binary mixtures of sulfonamides.

Different methods for analyzing binary mixtures by using 2 wavelengths are reviewed. The absorbance ratio calculated at 2 wavelengths, not including the isoabsorptive point, was a quadratic function of relative concentration. The curve-fitting process using orthogonal polynomials was applied to obtain the quadratic equation. An absorbance ratio can be used as a rapid purity index for sulfacetamide sodium in the presence of sulfanilamide. Sulfacetamide sodium has been determined in eye drop preparations.     

Gas-liquid chromatographic/mass spectrometric screening method for T-2 toxin in milk

A method for the analysis of T-2 toxin in milk is presented. Ethyl acetate extracts of milk samples which had been spiked with T-2 toxin were purified by thin layer chromatography and derivatized with N,O-bis(trimethylsilyl)acetamide to produce the T-2 toxin trimethylsilyl ether (T-2 toxin-TMS). N,O-bis(trimethylsilyl-d9)acetamide was used to make T-2 toxin d9-trimethylsilyl ether (T-2 toxin-d9 TMS) which was added to the derivatized milk extract as an internal standard. Samples were analyzed by combined gas-liquid chromatography/mass spectrometry using either electron impact ionization or chemical ionization mass spectrometry. In electron impact ionization analyses, simultaneous monitoring of the T-2 toxin-TMS fragment ion at m/z 436 and the T-2 toxin-d9TMS fragment ion at m/z 445 gave a T-2 toxin-TMS detectability estimated at 6 microgram/kg. In chemical ionization analyses, the T-2 toxin-TMS fragment ion at m/z 377 and the T-2 toxin-d9TMS fragment ion at m/z 386 were simultaneously monitored to give a T-2 toxin-TMS detectability estimated at 3 microgram/kg. Average recovery was 85% at 200 microgram/kg and 65% at 20 microgram/kg.     

A comparison of continuous grazing systems for milk production

In two experiments conducted with Ayrshire dairy cows in 1974 and 1975 on swards of S23 perennial ryegrass, four systems of continuous grazing were investigated. The leys received 345 and 370 kg ha^-1 fertilizer nitrogen in 1974 and 1975 respectively and were stocked at the rate of five cows per ha. In 1974, a comparison was made between two systems which either integrated silage making with, or separated it from, the continuous grazing. The provision of a silage aftermath in late July increased milk yield after that time, but had no significant effect on milk yield over the 19-week experimental period. In 1975, a comparison between weekly and monthly applications of fertilizer N showed no significant differences between milk yields in a 20-week period. The feeding of supplementary concentrates from late July onwards significantly increased milk yield. The treatments in both years had only small and mainly non-significant effects on milk composition. On average, excluding the concentrate treatment, the annual output of milk was 10,800 kg ha^-1 using spring-calved cows.     

Inoculation of pines with mycorrhizal fungi in natural soils—III: Effect of soil fumigation on rate of infection and response to inoculum density

Pinus radiata seedlings were inoculated with basidiospores of Rhizopogon roseolas and Suillus granulatus, and with chlamylospores of two unidentified but highly effective mycorrhizal fungi in undisturbed cores of natural soil fumigated with methyl bromide. Fumigation stimulated mycorrhizal infection rate and enhanced the response of seedlings to increasing concentrations of both inoculum types, but the effect of chlamydospore inoculum was more favoured by fumigation than that of basidio-spores. Chlamydospore inocula appear more sensitive to competitive and antagonistic soil microorganisms than basidiospores. Soil fumigation appears a necessary adjunct to the use of chlamydospores as inoculants in nurseries and is discussed in relation to nursery culture of pines.