Ichnostratigraphic correlation of Lower Palaeozoic clastics in the Kufra Basin (SE Libya)

The Lower Palaeozoic deposits in North Africa are dominated by sandstones and shales which often lack biostratigraphically useful body fossils. Trilobite burrows ( Cruziana ) partly fill this gap and provide the basis for medium-resolution stratigraphic interpretations. Several Ordovician-Silurian ichnostratigraphically significant Cruziana forms have been found and studied in the Kufra Basin (SE Libya), including C. goldfussi and C. furcifera from the Lower Ordovician Hawaz Fm. and a new ichnospecies, C. kufraensis , occurring in transgressive sandstones at the base of the Lower Silurian Tanezzuft Fm. The upper Tanezzuft Fm. and Akakus Fm. typically contain C. acacensis , a form that is characteristic of the Lower Silurian of Northern Gondwana.     

Molecular characterisation of resistance against potato wart races 1, 2, 6 and 18 in a tetraploid population of potato (Solanum tuberosum subsp. tuberosum)

Potato wart is caused by the obligate biotrophic fungus Synchytrium endobioticum, which is subject to quarantine regulations due to the production of long persisting spores in the soil and the lack of effective fungicides. The objective of this study was to identify quantitative trait loci (QTL) for resistance against potato wart races (R) 1, 2, 6 and 18 in a tetraploid potato population developed by crossing cv. Saturna (resistant to R1) with cv. Panda (resistant to R1, R2, R6, R18). A total of 92 progenies were used for phenotyping and genotyping. Resistance tests were performed for races 1 and 18 in 2 years and for races 2 and 6 in 1 year on 10 to 20 eyepieces per genotype. Based on amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers, linkage maps were established for the female and male parent, respectively. Single marker analysis followed by a multiple regression analysis revealed initial marker–trait associations. The interval mapping routine of TetraploidMap was applied for QTL analysis. A major QTL for resistance against race 1 explaining between 46 % and 56 % of the phenotypic variation was identified near Sen1, a known resistance locus for potato wart race 1 on chromosome XI. Other resistance QTL were detected on chromosomes I (to R2), II (to R6, 18), VI (to R1, 2, 6, 18), VII (to R2, 6, 18), VIII (to R1, 2, 6, 18), X (to R2, 6, 18), XI (to R2, 6, 18) and on an unknown linkage group (to R18) explaining minor to moderate effects of the phenotypic variation. Resistance QTL against different potato wart races often overlapped, particularly concerning races 2, 6 and 18. Overall, this study gives a valuable insight into the complex inheritance of resistance against potato wart.     

Triglochinin in Araceen

Five species of four subfamilies of the Araceae contain triglochinin as the only cyanogenic glucoside. The compound was identified by TLC, PC, IR, NMR and hydrolysis with a triglochinin-specific β-glucosidase.     

Cyanoglucoside storing cuticle of Zygaena Larvae (Insecta,Lepidoptera)

Summary As a deterrent against predators, larvae of Zygaena trifolii release droplets of fluid containing cyanoglucosides from segmentally arranged cuticular cavities. Histological examinations show that during the moulting period, the old cuticle, including the cavities and the secretion within them, is degraded, with the exception of a thin mesocuticular layer forming the exuviae. When the endocuticular layer of the new cuticle is deposited, the cuticle detaches from the underlying epidermis in specific areas, which leads to the formation of the cuticular cavities. During a moult-intermoult sequence the concentration of cyanoglucosides in both the haemolymph and the defensive secretion shows specific changes. These changes seem to be related to the formation and degradation of the cavities. We suggest that during the moult the cyanoglucosides are transported through the epidermis into the haemolymph to prevent them from being wasted with the exuviae and, after ecdysis, are retranslocated into the newly formed cavities.     

Ichnocoenoses of a turbidite sole

Specimens of 13 ichnospecies and their spatial distributions were analyzed on a spectacular cast of a turbidite sole surface (2.9 m²), from Eocene flysch of Spain. The distribution tends to be patchy. Except for postturbidite Granularia, no intraspecies overcrossing was observed. Overlapping and intersecting graphoglyptids indicate that they were formed at different times. This difference may result from (1) ecologic succession of their producers, (2) upward migration of a tiered community following sediment accretion, or (3) synchronous burrowing on the whole area, the specific places of occupation shifting with time.