Production of Potato Spindle Tuber Viroid (PSTV) by Large Scale Fermentation of PSTY-Infected Potato Cell Suspension Cultures

Berlin, J., Wray, V., Forche, E., Reng, H.–G , Schler,H, Luckinger, R. and Mhlbach, H.–P. 1985. Production ofpotato spindle tuber viroid (PSTV) by large scale fermentationof PSTV–infected potato cell suspension cultures.—J.exp. Bot 36: 1985–1995. Cell suspension cultures of Solatiumdemissum, infected with the potato spindle tuber viroid (PSTV),were scaled up to volumes of up to 800 dm³ to provide sufficientand uniform plant material for subsequent studies on viroidbiosynthesis. Here we describe the technological aspects ofproducing the required amounts of biomass and viroid. The cells,which had been maintained on a medium containing expensive coconutmilk, were first adapted to rapid growth on the less expensiveB5–medium. The physiological state of the cells was monitoredby in vivo ³¹P–NMR spectroscopy Under the chosen conditionsthe scale–up from 10 dm³ inoculum from shake flasks tothe harvest of the 800 dm³ stirred fermenter lasted 38 d andprovided 112 kg biomass. Growth characteristics and viroid productionin shake flasks and large bioreactors were rather similar. Gelelectrophoretic analysis of isolated nucleic acids using silverstaining and Northern blot hybridization revealed a PSTV–contentof approximately 700 µg PSTV per kg fresh mass of culturedcells. Key words: Solanum demissum, plant cell cultures, potato spindle tuber viroid, biomass production, fermentation, in vivo ³¹P-NMR     

An Electron Microscope Study of the Path of Water Movement in Transpiring Leaves of Cotton (Gossypium hirsulum L.)

Precipitation of ferrocyanide by ferric ions in cotton leavesproduced electron-opaque crystals visible with othe electronmicroscope and identifiable as Prussian blue by X-ray and electrondiffraction. These crystals were formed within the lumina andexposed primary walls of the tracheary elements but not withintheir secondary walls. The precipitation pattern indicated thatwater moved from the tracheary elements into the parenchymaof the bundle sheath and bundle sheath extensions. From thesecells water moved into the epidermis or through the mesophyllto the transpirational exits. Prussian blue accumulated in thewalls of cells lining the substomatal cavities and to a lesserextent between adjacent covering hairs. Ferrocyanide anionsdid not follow the water stream through the cuticle. In parenchymaand epidermal cells Prussian blue crystals were found withinthe primary wall, in the region between the plasma-lemma andthe cell wall, and within the protoplast.     

Covert Categories and Folk Taxonomies

Much of the recent work in ethnoscience has been concerned with the nature of folk taxonomies, an often stated definition of which requires that all folk taxa be monolexemically labeled. This paper offers evidence that unlabeled categories may also be of crucial taxonomic significance, and we feel that it is inappropriate to treat such categories apart from the named taxonomic entities of the system. More importantly, evidence presented indicates that by recognizing unnamed taxa one may gain an understanding of the structure of a particular semantic domain that is actually obscured if one focuses solely on lexically labeled units.     

General Principles of Classification and Nomenclature in Folk Biology

Since about 1954, modern field research has been carried out by a number of ethnographers and biologists in an effort to understand more fully the nature of folk biological classification. Much of this work has been devoted to studies dealing with the naming and classification of plants and animals in non-Western societies. It has now become apparent that several important and far reaching generalizations can be formulated which promise to throw considerable light on prescientific man's understanding of his biological universe.     

Genetic diversity and differentiation among Lagopus lagopus populations in Scandinavia and Scotland: evolutionary significant units confirmed by SNP markers

Single Nucleotide Polymorphism in four Scandinavian populations of willow grouse (Lagopus lagopus) and two Scottish populations of red grouse (Lagopus lagopus scoticus) were assessed at 13 protein‐coding loci. We found high levels of diversity, with one substitution every 55 bp as an average and a total of 76 unlinked parsimony informative SNPs. Different estimators of genetic diversity such as: number of synonymous and non‐synonymous sites, average number of alleles, number and percentage of polymorphic loci, mean nucleotide diversity (π_s, π_a) and gene diversity at synonymous and non‐synonymous sites showed higher diversity in the northern populations compared to southern ones. Strong levels of purifying selection found in all the populations together with neutrality tests conforming to neutral expectations agree with large effective population sizes. Assignment tests reported a clear distinction between Scandinavian and Scottish grouse suggesting the existence of two different evolutionary significant units. The divergence time between willow and red grouse ranging between 12 500 and 125 000 years, in conjunction with the presence of ‘specific’ markers for each subspecies prompt a reassessment of the taxonomical status of the Scottish red grouse.