HONEYDEW SUGARS ELIMINATED BY STIGMACOCCUS SP. NR. ASPER HEMPEL (HEMIPTERA: MARGARODIDAE) FEEDING ON LEGUMINOUS TREES IN BRAZIL.

HONEYDEW SUGARS ELIMINATED BY STIGMACOCCUS SP. NR ASPER HEMPEL (HEMIPTERA: MARGARODIDAE) FEEDING ON LEGUMINOUS TREES IN BRAZIL. The sooty mould coating the trunks of mature trees of Schizolobium excelsum in Brazil was found to be associated with honeydew being eliminated by an undescribed species of margarodid near Stigmacoccus asper Hempel. Analysis of the honeydew sugars by paper chromatography revealed a complex composition. The principal sugar was sucrose, but there were significant amounts of fructose, glucose and three components identified as di-, tri- and tetrasaccharides. The disaccharides were maltose, trehalose, trehalulose and a hexose-hexitol. The other, apparently novel, pair of oligosaccharides were composed of glucose(s) 1,4 linked to the glucose of sucrose. The sugar composition of the tree sap was also determined and found to be glucose and sucrose only. The findings, therefore, imply significant and novel metabolic transformations of sugars by the scale insect and/or its microbial symbionts. Key words: Xylococcinae, sexual reproduction, stigmatriose, stigmatetraose, Amazonia

Relations among sorghum ergot strains from the United States, Mexico, Puerto Rico, Bolivia, India and Australia

Sorghum ergot, initially restricted to Asia and Africa, was recently found in the Americas and Australia. Three species causing the disease have been reported: Claviceps sorghi in India, C. sorghicola in Japan, and C. africana in all ergot-positive countries. The objective of our study was to study the intraspecific variation in C. africana isolates in the Americas, Africa, India, and Australia. We confirmed C. africana, C. sorghi, and C. sorghicola as different species using differences in nucleotide sequences of internal transcribed spacer 1 and 5.8S rDNA regions. Sequences of this region obtained from the representative American, Indian, and Australian isolates of C. africana were identical. In addition, random amplified polymorphic DNA (RAPD) banding patterns of sorghum ergot pathogen isolates from the United States, Mexico, Puerto Rico, Bolivia, Australia, and India were evaluated with nearly 100 primers. A total of 65 primers gave identical patterns for all isolates, which confirmed that all were C. africana. The identity of RAPD pattern and rDNA sequence of Indian isolates with those of C. africana confirmed that the species is now present in India. Only 20 primers gave small pattern differences and 7 of them were used for routine testing. All of the American isolates were identical and three isolates of the same type were also found in South Africa, suggesting Africa as the origin of the invasion clone in the Americas. Australian and Indian isolates were distinguishable by a single band difference; therefore, migration from the Asian region to Australia is suspected. Another distinct group was found in Africa. Cluster analysis of the informative bands revealed that the American and African group are on the same moderately (69%) supported clade. Isolates from Australia and India belonged to another clade

Influence of halogen salts on the production of the ochratoxins by Aspergillus ochraceus Wilh.

The first report of the biological production of bromo ochratoxin B by Aspergillus ochraceus Wilh. is presented as well as a study of the influence of potassium bromide, potassium iodide, potassium fluoride, and potassium chloride on the production of ochratoxin A and ochratoxin B. Potassium fluoride and potassium iodide inhibited the growth of the fungus, whereas potassium chloride substantially stimulated the production of ochratoxin A in shaken solid substrate fermentation on whole wheat or shredded wheat, generally giving a high yield of ochratoxins. Increasing levels of potassium bromide led to a decline in ochratoxin A production and an increase in bromo- ochratoxin B, ochratoxin B, and 4-hydroxy ochratoxin B. Nevertheless, A. ochraceus was much less versatile in the bromo analogues than other fungi, which produce metabolites containing chlorine. Analysis included aminopropyl solid-phase extraction column cleanup followed by quantitative analysis on reversed-phase HPLC using fluorescence detection and employing N-(5-chloro-2- hydroxybenzoyl)-phenylalanine as an internal standard.Articl