Preliminary search for a νirus in Dacus oleae Gmel. populations in Northern Greece

Στην περίοδο από Ιούλιο έως Δεκέμβριο 1984 συλλέχΟησαν 4.5 g ακμαίων, 8.5 g υγιών προνυμφών και 0.45 g νεκρών προνυμφών του εντόμου Dacus oleae Gmel. από περιοχές της Βόρειας Ελλάδας, που χαρακτηρίζονταν από Βαριά προσβολή των ελαιοδένδρων από δάκο, στα οποία δεν εφαρμόστηκε χημική καταπολέμηση. Τα δείγματα εξετάσθηκαν για εγκλεισμένους και μη εγκλεισμένους ιούς με τη χρησιμοποίηση φυγοκεντρήσεων, οπτικού και ηλεκτρονικού μικροσκοπίου, ανάλυσης νουκλεϊ νικών οξέων KUI πειράματα μολυσματικότητας. Στα δείγματα των νεκρών προνυμφών, και σε αντίθεση με εκείνα των υγιών προνυμφών και των ακμαίων, εντοπίσθηκαν και απομονώθηκαν ιόμορφα σωμάτια. Τα σωμάτια αυτά είχαν διάμετρο περίπου 35 nm και μερικά ήταν άδεια, όπως φάνηκε από τη διείσδυση της χρωστικής κατά την αρνητική χρώση. Δεν κατέστη δυνατός ο παραπέρα χαρακτηρισμός των «ιοσωματίων» για το λόγο έλλειψης αρκετής ποσότητας δείγματος, ενώ προσπάθειες πολλαπλασιασμούτους σε προνύμφες του λεπιδόπτερου Galleria mellonella και σε καλλιέργειες κυττάρων Drosophila melanogastcr αποδείχθησαν ανεπιτυχείς. Αν και τα μικρά ιόμορφα σωμάτια ήταν το μοναδικό πιθανό παθογόνο αίτιο που αναγνωρίστηκε στις νεκρές προνύμφες, φαίνεται κάπως απίθανο να αποτελούν και το μοναδικό αίτιο του θανάτου για το λόγο του σχετικά μικρού αριθμού τους. Πάντως αν καταστεί δυνατό να πολλαπλασιασθούν οι «ιοί» αυτοί σε εκτροφές του δάκου της ελιάς ή σε καλλιέργειες κυττάρων ιστών του ίδιου εντόμου, ίσως να αποτελέσουν στο μέλλον ένα βιολογικό μέσο καταπολέμησης του.A large number of larvae of Dacus oleae were collected from infested olives in Northern Greece, and a small proportion of these were found to be dead. Adult flies were caught in McPhail traps at the same locations. The larvae and adults were fractionated by a series of steps designed to identify occluded and nonoccluded viruses. Virus-like particles were identified in small amounts only in the dead larvae

A short purification process for quantitative isolation of PrP(Sc) from naturally occurring and experimental transmissible spongiform encephalopathies

BACKGROUND: Transmissible spongiform encephalopathies (TSEs) are neurodegenerative diseases affecting both humans and animals. They are associated with post-translational conversion of the normal cellular prion protein (PrP(C)) into a heat- and protease-resistant abnormal isoform (PrP(Sc)). Detection of PrP(Sc) in individuals is widely utilized for the diagnosis of prion diseases. METHODS: TSE brain tissue samples have been processed in order to quantitatively isolate PrP(Sc). The protocol includes an initial homogenization, digestion with proteinase K and salt precipitation. RESULTS: Here we show that over 97 percent of the PrP(Sc) present can be precipitated from infected brain material using this simple salting-out procedure for proteins. No chemically harsh conditions are used during the process in order to conserve the native quality of the isolated protein. CONCLUSION: The resulting PrP(Sc)-enriched preparation should provide a suitable substrate for analyzing the structure of the prion agent and for scavenging for other molecules with which it may associate. In comparison with most methods that exist today, the one described in this study is rapid, cost-effective and does not demand expensive laboratory equipment

Mammalian prions: Tracking the infectious entities

Protein misfolding is central to the pathogenesis of several neurodegenerative disorders. Among these disorders, prion diseases are unique because they are transmissible. The conversion of the host-encoded GPI-anchored PrP protein into a structurally altered form is crucially associated with the infectious and neurotoxic properties of the resulting abnormal PrP. Many lines of evidence indicate that distinct aggregated forms with different size and protease resistance are produced during prion multiplication. The recent isolation of various subsets of abnormal PrP, along with the improved biochemical tools and infectivity detection assays have shed light on the diversity of abnormal PrP protein and may give insights into the features of the more infectious subsets of abnormal PrP

The argan - multipurpose tree of Morocco

Joseph Hooker and John Ball, writing of Argania spinosa (L.) Skeels, said that "this tree is rightly regarded as the most interesting vegetable product of Marocco, being confined to that empire and to a very circumscribed area in it, belonging to an almost exclusively tropical family, yielding a most important article of diet to the inhabitants, and a wood that for hardness and durability rivals any hitherto described" (Hooker & Ball, 1878). More than a century later the argan continues to be of manifold interest; to the botanist and ecologist because of its apparent Moroccan endemism and its disjunct distribution in relation to its family, the Sapotaceae; to the food technologist because of its highly nutritious oil whose untapped commercial potential is hindered by problems with its extraction; and to foresters and local inhabitants because of its central role as a stabilizer of soil and as a source of fuel and food for goats. There must now, however, be added a further interest in the argan: a grave concern for its future