Variation in Heterobasidion annosum detected by Random Amplified Polymorphic DNAs

The production of Random Amplified Polymorphic DNAs (RAPDs) by Polymerase Chain Reaction (PCR) was used to detect variation in the isolates of Heterobasidion annosum with various geographical origins. Specific RAPD products were detected for each of the intersterility groups: the European S, F, P and the North American S group. There was considerably more polymorphism found among European S than P isolates. The analysis of RAPDs was shown to be a simple and a fast way to generate DNA markers specific to the previously established intersterility groups and thus useful for diagnostic purposes.     

The impact of small-scale design interventions on the behaviour patterns of the users of an urban wasteland

Urban derelict space can form a valuable complementary element to the formal green spaces of a city: wastelands are often biologically diverse and their unregulated status can provoke innovative spatial activities by a wide range of users. Using the case of an urban brownfield in Tallinn, Estonia, this paper examines how such a space is used and evaluates the magnitude of the impact of minor design interventions – so-called urban acupuncture – on the activities carried out by the users. The study used field observations and behaviour mapping to compare the spatial pattern of the users before and after small design interventions. Although there was widespread use beforehand there was both an increase in use and a different pattern afterwards, which was clearly detectable from the composite behaviour maps of both arrangements, where users follow the properties of the particular environment. The small improvements tested showed the largest effect on the female and the older user groups, raising the number of overall visits and increasing the occurrence of active behaviour almost five times. The research demonstrates that small, inexpensive and possibly temporary interventions can have a major positive effect.     

Genetic basis of penicillin resistance of S. aureus isolated in bovine mastitis

Background

The blaZ gene encoding penicillin resistance can be located either chromosomally or on plasmids. The aim of this study was to investigate the genetic relationships and to determine the location of the blaZ gene in S. aureus isolated in bovine mastitis in Finland and Sweden.

Methods

Seventy-eight β-lactamase positive S. aureus isolates from bovine mastitis (34 from Finland and 44 from Sweden) were included in the study. The localization of blaZ gene was determined by Southern blotting. The blaZ genes of the isolates were sequenced and the sequences were translated to beta-lactamase proteins and further grouped as different protein signatures. The isolates and, as control, 33 Swedish and 36 Finnish beta-lactamase negative isolates were typed with pulsed-field gel electrophoresis (PFGE).

Results

In 26 out of 34 Finnish isolates (76.5%) and in 25 out of 44 Swedish isolates (56.8%) the blaZ gene was localized on a plasmid. Six different protein signatures were found. One signature was found only in four Swedish isolates, but all other signatures were found both in Finnish and Swedish isolates. The PFGE results revealed a diversity of S. aureus clones. The protein signatures were not clearly associated with certain pulsotypes.

Conclusions

The plasmid location of the blaZ gene was not statistically significantly more common in Finland than in Sweden, and hence does not explain the higher proportion of penicillin-resistant isolates of S. aureus causing bovine mastitis in Finland compared to Sweden.     

Genetic Analysis of Metalaxyl Insensitivity Loci in Phytophthora infestans Using Linked DNA Markers

ABSTRACT Previous studies indicated that incompletely dominant loci determine insensitivity by oomycetes to phenylamide fungicides such as metalaxyl. To compare the bases of insensitivity in different strains of the late blight pathogen, Phytophthora infestans, crosses were performed between sensitive isolates and isolates from Mexico, the Netherlands, and the United Kingdom that displayed varying levels of insensitivity. Segregation analyses indicated that metalaxyl insensitivity was determined primarily by one locus in each isolate, and that two of the isolates were heterozygous and the other homozygous for the insensitive allele. Metalaxyl insensitivity was also affected by the segregation of additional loci of minor effect. DNA markers linked to insensitivity were obtained by bulked segregant analysis using random amplified polymorphic DNA (RAPD) markers and the Dutch and Mexican crosses. By studying the linkage relationships between these markers and the insensitivity in each cross by RAPD or restriction fragment length polymorphism analysis, it appeared that the same chromosomal locus conferred insensitivity in the Mexican and Dutch isolates. However, a gene at a different chromosomal position was responsible for insensitivity in the British isolate.     

Spatial eco-evolutionary feedback in plant-pathogen interactions

In recent years the potential for evolutionary change to drive ecological dynamics, and vice versa, has been widely recognized. However, the convincing examples of eco-evolutionary dynamics mainly stem from highly artificial experimental systems, with conspicuously few examples contributed by field systems. While rarely considered in the eco-evolutionary literature, the gene-for-gene hypothesis inherently recognizes the tight link between evolutionary and ecological dynamics. The boom-and-bust dynamics of some agricultural pathogens are an extreme demonstration of this. In this perspective, we place plant-pathogen systems in a spatial eco-evolutionary framework, which recognizes that ecology and evolution are tightly linked, take place at the same time scale and are strongly influenced by spatial structure. Specifically, we: i) exemplify how the ecological process of dispersal modifies rapid local coevolutionary dynamics and thereby shapes spatial variation in resistance, infectivity, and local adaptation; and ii) illustrate how the outcome of coevolution (spatial distribution in resistance, infectivity and local adaptation) drives ecological metapopulation processes. Overall, we conclude that both agricultural and wild pathosystems provide a unique illustration of the high relevance of spatial eco-evolutionary feedback in understanding species interactions.     

Beobachtungen am Schlehenspinner (Orgyia,antiqua L.) und seinen Parasiten

Zusammenfassung 1. Das erstmalige Massenauftreten des Schlehenspinners in Fichtenwäldern Süddeutschlands bot Gelegenheit, im Walde und Labor Beobachtungen an diesem seltenen Forstschädling und seinen Parasiten anzustellen. In warmen Gegenden und Jahren durchläuft er zwei Generationen (Bionomieformel: I = 67–78/ 9 + 9, II = 9,5–46/6 + 67).2. Die Altraupe hat Brennhaare. Längeres Arbeiten mit den Puppenkokons verursacht ein heftiges Nesselfieber (Urticaria).3. Gradationen des Schlehenspinners in mitteleuropäischen Forsten treten in 50–60jährigen Intervallen auf. Eine Standortgebundenheit ist nicht erkennbar. Die Altraupe verschont die Knospen, ein mehrjä hriger starker Fraß in denselben Beständen ist selten, er verursacht nur einen Zuwachsverlust. Die Gradation findet meist im Innern geschlossener Bestände statt.4. Im Untersuchungsgebiet, 7 km nördlich von Bad Wurzach, ermittelten wir an der 2. Generation des Jahres 1971 einen Weibchenanteil von 48,4% und eine Puppenmortalität von 4,4%. Die Zahl abgelegter Eier war im Zentrum geringfügig höher als im Randgebiet.5. Häufigste Parasiten waren der PuppenparasitCoccygomimus turionellae (L.), der LarvenparasitPhobocampe crassiuscula (Grav.) und der EiparasitTelenomus dalmanni Ratz. Die Besatzdichte der vorgenannten Schmarotzer wurde im Zentrum und Randgebiet untersucht.6. Systematische Stellung, Wirtsspektrum, Lebensdauer, Sexualindex und Parasitierungsverhalten vonTelenomus dalmanni Ratz. werden beschrieben.

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Summary 1. The first appearance in large numbers ofOrgyia antiqua in the spruce forest of Southern Germany offered the possibility of observing this insect pest and its parasitoides under field and laboratory conditions. In warm regions and years this insect has two generations (Bionomic data [Bionomieformel] I = 67–78/9 + 9, II = 9,5–46/6 + 67).2. The older larva has poisoned hairs. Extended handling with the cocoon causes a heavy kind of feaver (Urticaria).3. The outbreak ofOrgyia antiqua in middle-european forests occurs in intervals from 50 to 60 years. A preference of special areas could not be seen. The older larva doesn't attack the buds. A high population over several years in the same stands is very seldom. This high population density causes only a loss of increment. The outbreak mostly takes place in the center of closed forests.4. In the study area (about 7 km north of Bad Wurzbach, Baden-Württemberg) we found 48.4% females for the second generation. The mortality of the pupa was 4.4 %. The number of eggs laid was found to be higher in the center than in the peripheral zones.5. The most important parasitoides wereCoccygomimus turionellae (L.) (pupae),Phobocampe crassiuscula (Grav.) (larvae) andTelenomus dalmanni (Ratz.) (eggs). The density of population of these parasitoides has been studied in heavy infested areas as well as in scarcely poculated zones.6. Systematics, host-species, duration of life, sexual index and the behavoir of the parasitoidTelenomus dalmanni are described.

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Als Stipendiat der Alexander v. Humboldt-Stiftung am Institut für biologische Schädlingsbekämpfung tätig.     

Occurrence and characterization of methicillin-resistant staphylococci from bovine mastitis milk samples in Finland

Background

Methicillin-resistant staphylococci (MRS) are increasingly being isolated in bovine mastitis. The aim of our study was to evaluate the occurrence of MRS in Finnish mastitis milk samples and characterize the MRS isolates using molecular methods.

Results

Methicillin-resistant S. aureus (MRSA) was a rare finding in bovine mastitis in Finland. Only two out of 135 (1.5%) S. aureus isolates were positive for mec genes. One of these carried mecA and was of spa type t172, SCCmec type IV and ST375, and the other harboured mecC, being spa type t3256, and ST130. MRSA ST375 is common among human MRSA isolates in Finland, but this is the first report in the country of bovine mecC MRSA. In coagulase-negative staphylococci (CoNS) originating from bovine mastitis, methicillin resistance was more common. In the two CoNS collections studied, 5.2% (17/324) and 1.8% (2/110) of the isolates were mecA positive. Eighteen of these were methicillin-resistant S. epidermidis (MRSE), which were divided into 6 separate PFGE clusters. One pulsotype was detected in different parts of the country, indicating clonal spread. Most MRSE (13/18) were of SCCmec type IV, one was of type V and four were non-typeable. Comparison with a human staphylococcal database indicated that bovine MRSE strains were not closely related to human MRSE isolates.

Conclusions

The occurrence of MRS, especially MRSA, in bovine mastitis in Finland was low. Most methicillin-resistant bovine CoNS are MRSE, and we found evidence of a bovine MRSE strain that may spread clonally. This is the first report of a Finnish bovine isolate of MRSA_mecC ST130. The study provides a baseline for further MRS monitoring.     

Retention patches maintain diversity of epiphytic and epixylic indicator lichens more effectively than solitary trees

The effectiveness of retention trees and patches in preserving diversity of nine epiphytic and epixylic old-growth forest lichens was studied in north boreal spruce forests in Finland. We compared (1) 7–8-year-old retention cuts, with at least 5–10 living or dead retention trees per hectare, (2) 10–12-year-old clear-cuts, with some scattered living and dead retention trees on the sites, (3) old-growth spruce forests, and (4) 7-8-year-old retention patches (0.06–0.45?ha) representing the original tree species composition of old-growth forests. The occurrence of indicator lichens was studied on 150 deciduous trees and snags in each forest category. The species richness was significantly higher in old-growth forests than in the clear-cuts and retention cuts, but did not differ between old-growth forests and retention patches. Only three species were found in clear-cuts and two in retention cuts. Foliose cyanolichens Leptogium saturninum and Nephroma bellum thrived on solitary retention trees, whereas humidity-requiring pin lichens from the genus Chaenotheca were found only in old-growth forests and retention patches. Our results suggest that the ability of epiphytic and epixylic species to survive on retained trees depends on several factors: (1) substrate quality (tree species, tree type and diameter of a tree), (2) environmental factors (e.g. humidity, slope exposition), and (3) morphological and physiological characteristics of species. Besides of substrate trees, the retained conifers (esp. spruce) seem to be important in retention patches to provide the shading necessary to maintain humidity.     

Effect of Germination and Water Content on the Microstructure and Rheological Properties of Two Rye Doughs

Two rye cultivars, Marder and Motto, with falling numbers 314 and 309, respectively, were germinated in vitro. Relative to the native grains, germination induced minor local changes in the microstructure of cell walls and proteins in the kernels. Kernels of germinated and native grains were milled, and doughs were prepared from the flours, with water content and incubation time varied according to experimental design. The viscoelastic properties of the doughs were measured just after mixing and after various incubation times. The area of blue fluorescence, a measure of intact cell walls, was quantified by computer-assisted image analysis in thin sections of rye dough after mixing and incubation, and the starch structure was studied under the microscope after iodine staining. The water content of the doughs was explained well by the rheological behavior. Doughs made from flours of germinated grains were always softer than doughs made from flours of native grains, and Marder doughs were always more rigid than Motto doughs. The higher the water content, and the longer the incubation time, the greater the rheological changes during incubation. Microstructural studies showed that germination and incubation caused changes in the cell wall structures of dough that might explain the softening of the doughs.