PRELIMINARY STUDIES ON POTATO APHIDS IN NORTH AND NORTH-EAST SCOTLAND

Studies of potato aphids made in the potato seed-growing areas of north and north-east Scotland during 1950-3 showed that potato plants were first infested during July, but with few aphids; maximum populations did not develop until mid-late August or early September, which is the period of potato haulm destruction in seed crops. Myzus persicae (Sulzer) was scarce in rural districts and most numerous near urban areas. The main influx of alatae occurred in early August. Aulacorthum solani (Kltb.) was the predominant species north of Inverness. Macrosiphum euphorbiae (Thomas) was present in small numbers in many potato fields, but Aphis nasturtii (Kltb.) was extremely scarce.
Because of the small numbers of aphids found during two years by examining two or three compound leaves per haulm, it was preferable to count the aphids on one main stem and all its leaves.
Stove-pipe sticky traps provided information complementary to complete stem/leaf examination, but are considered to be of doubtful use in an area where aphids are few.     

Time Space Translation: A Hox Mechanism for Vertebrate A-P Patterning

The vertebrate A-P axis is a time axis. The head is made first and more and more posterior levels are made at later and later stages. This is different to the situation in most other animals, for example, in Drosophila. Central to this timing is Hox temporal collinearity (see below). This occurs rarely in the animal kingdom but is characteristic of vertebrates and is used to generate the primary axial Hox pattern using time space translation and to integrate successive derived patterns (see below). This is thus a different situation than in Drosophila, where the primary pattern guiding Hox spatial collinearity is generated externally, by the gap and segmentation genes.     

Effect of trapidil derivative AR 12456 on intracellular cholesterol homeostasis in human hepatoma cell line Hep G2

The effect of trapidil derivative AR12456 on intracellular cholesterol metabolism was investigated in human hepatoma cell line HepG2. AR12456 enhanced the uptake and degradation of¹²⁵I-LDL in a dose-dependent manner. The drug inhibited cholesterol synthesis and esterification without affecting cellular cholesterol content and bile acid synthesis; cholesterol efflux was slightly increased. These results show that the inhibition of cholesterol synthesis together with the enhanced expression of LDL receptors may partially explain the hypocholesterolemic activity of compound AR12456.     

A new aero-aquatic hyphomycete from Papua New Guinea and Australia

An aero-aquatic hyphomycete with setose synnemata and scolecospores with a central isthmus is described.     

The biology, egg and larvae of Acaenitus dubitator (Panzer) (Hymenoptera, Ichneumonidae: Acaenitinae)

Acaenitus dubitator (Panzer) is found to be a koinobiont endoparasitoid of the larva of an endophytic beetle, Cleonis piger (Scopoli) (Curculionidae), in Britain, suggesting a similar mode of development for the ichneumonid subfamily Acaenitinae as a whole. The parasitoid can overwinter in its cocoon in one of two ways. Individuals overwintering as essentially unaltered mature larvae do not become adult the following summer, while those that overwinter as morphologically distinct prepupae are committed to pupate and become adult immediately afterwards. The change from mature larva to prepupa takes place in late summer, soon after the time of cocoon formation, but a proportion of mature larvae lie over in the first year, and perhaps subsequently. This appears to be an adaptation to life in a particularly harsh and uncertain environment. The egg, prepupa, and first, second and final instar larvae are described and figured. Previous interpretations of the cephalic sclerites of final instar acaenitines are revised.     

Mapping carcass and meat quality QTL on Sus Scrofa chromosome 2 in commercial finishing pigs

Quantitative trait loci (QTL) affecting carcass and meat quality located on SSC2 were identified using variance component methods. A large number of traits involved in meat and carcass quality was detected in a commercial crossbred population: 1855 pigs sired by 17 boars from a synthetic line, which where homozygous (A/A) for IGF2. Using combined linkage and linkage disequilibrium mapping (LDLA), several QTL significantly affecting loin muscle mass, ham weight and ham muscles (outer ham and knuckle ham) and meat quality traits, such as Minolta-L* and -b*, ultimate pH and Japanese colour score were detected. These results agreed well with previous QTL-studies involving SSC2. Since our study is carried out on crossbreds, different QTL may be segregating in the parental lines. To address this question, we compared models with a single QTL-variance component with models allowing for separate sire and dam QTL-variance components. The same QTL were identified using a single QTL variance component model compared to a model allowing for separate variances with minor differences with respect to QTL location. However, the variance component method made it possible to detect QTL segregating in the paternal line (e.g. HAMB), the maternal lines (e.g. Ham) or in both (e.g. pHu). Combining association and linkage information among haplotypes improved slightly the significance of the QTL compared to an analysis using linkage information only.