Gap felling as a forest harvesting method in boreal forests: responses of carabid beetles (Coleoptera, Carabidae)

In order to study the ecological effects of logging combined with mechanical soil preparation, we sampled carabid beetles with pitfall trapping in nine spruce-dominated stands in central Finland in 1995–1998. Three of the stands were left intact as controls. Three 1600-m² openings per stand were logged in the winter 1995–1996 into six stands. In three of these stands, light soil preparation was applied. Logging affected the species assemblages, but soil preparation per se had no clear effects. Open-habitat species increased in abundance in the openings one year after logging, but catches of generalist species in the different treatments did not differ from each other. A forest species, Calathus micropterus , was least abundant in the prepared openings. The amounts of logging residue, exposed mineral soil and aggregated humus, as well as the abundance of red wood ants, significantly explained variation in carabid assemblages.     

Immunoglobulin constant kappa gene alleles in twelve strains of mice

Genomic DNA for the immunoglobulin (Ig) constant kappa Igk-C gene region was amplified by the polymerase chain reaction (PCR) method and sequenced from twelve commonly used inbred mouse strains. PCR products were used directly as templates in dideoxy-DNA-sequencing, a method which avoids the sequencing errors caused by Taq polymerase, since no cloning step is required. In restriction fragment length polymorphism (RFLP) studies the SJL mouse strain has been shown to belong to a Igk-C allogroup different from other common inbred mouse strains. The BALB/c Igk-C region was sequenced earlier, but our Igk-C sequences clarify the situation and confirm the existence of three Igk-C alleles in inbred mice (Mus musculus domesticus). Mice belonging to the kappa (Igk) haplotype e (SJL) have allele c of the Igk-C gene. The strains belonging to the kappa haplotype [a albino strain, K subline (AKR), PL and d (C58)] have allele a, and all other eight strains belonging to three different Igk haplotypes (b, c, and f) use allele b of the gene. Allele b has at least one (possibly two) nucleotide differences from allele a in the Igk-C region, but five compared to allele c. The allelic sequences also predict two allotypic kappa polypeptide chains among twelve inbred strains. Alleles a and b encode identical polypetides, but allele c (SJL) has a conserved lysine to arginine substitution in residue 142.The nucleotide sequence data reported in this paper have been submitted to the EMBL nucleotide sequence database and have been assigned the accession numbers X67002-X67012.     

Incompatibility of outer membrane proteins OmpA and OmpF of Escherichia coli with secretion in Bacillus subtilis: Fusions with secretable peptides

The secretion of the outer membrane proteins OmpA and OmpF of Escherichia coli has previously been found to be blocked at an early intracellular step, when these proteins were fused to a bacillar signal sequence and expressed in Bacillus subtilis. We have now fused these proteins to long secretable polypeptides, the amino-terminal portions of alpha-amylase or beta-lactamase. In spite of this, no secretion of the fusion proteins was detected in B. subtilis. With the exception of a small fraction of the beta-lactamase fusion, the proteins were cell-bound with uncleaved signal sequences. Protease accessibility indicated that the fusion proteins were not even partially exposed on the outer surface of the cytoplasmic membrane. Thus there was no change of the location compared to the OmpA or OmpF fused to the signal sequence only. We conclude that, like OmpA and OmpF, the fusion proteins fold into an export-incompatible conformation in B. subtilis before the start of translocation, which we postulate to be a late post-translational event.     

Biology student teachers’ dialogic talk in inquiry-based instruction

ABSTRACT

Inquiry-based learning has generally accepted by scholars as a most effective teaching approach in biology education. The talk during inquiry-based teaching needs to be practiced. There is less evidence how student teachers talk with students during their inquiry-based biology instruction. This knowledge is needed in supporting student teachers to develop their teachership in biology education. In this qualitative case study, the dialogic talk of biology student teachers (N = 6) was studied in the context of inquiry-based lessons in lower secondary school. The student teachers’ lessons were video and audio recorded and the data was analyzed using content analysis. The student teachers used dialogic talk in their inquiry-based instruction only occasionally, mainly in the examination and the conclusion stages. During the introduction stage, dialogic talk was less used and it was mainly explaining and instructing the content. In the examination stage, student teachers also guided students and stated facts. During the conclusion stage, student teachers mainly explained and also evaluated students’ statements. The lesson’s topics and methods used in inquiry-based learning may enable the dialogic talk of student teacher to some extent. However, teacher education should focus more on scaffolding student teachers’ talk with their students in all kinds of inquiry approaches.     

Distribution of a model biocontrol agent (Serenade® MAX) in apple and pear by mason bees and bumble bees

1. Biocontrol agents (BCAs) are commonly sprayed on flowering pipfruit trees to prevent them from getting infected by various pathogens. By entomovectoring, BCAs can be directly delivered onto the flowers. However, we currently lack knowledge on the distribution dynamics of BCAs by pollinators.
2. Here, managed bees, both bumble bees (Bombus terrestris) and mason bees (Osmia bicornis and Osmia cornuta), were placed in the vicinity of flowering pipfruit trees (pear -‘Conference’, and apple—‘Svatava’ and ‘Jonagold’), and this allowed us to investigate the distribution of a model BCA, namely, Serenade® MAX, from spray-inoculated flowers of a centralized tree to non-inoculated flowers of surrounding receiver trees by bees in an experimental setup in outdoor conditions.
3. One hour after inoculation, we detected an enrichment of BCA in the flowers of the receiver trees and this for each tested pipfruit.
4. The distribution of BCA from treated to untreated flowers was homogenous between the receiver trees for ‘Svatava’, while significantly different loads were detected for both ‘Conference’ and ‘Jonagold’, which might be due to differences in environmental factors, and/or bee characteristics.
5. More research is needed to understand the distribution dynamics of BCAs by pollinators in field conditions, such as in commercial orchards or crop fields, and how this could result in an efficient control.

     

Bacillus subtilisα-amylase: the rate limiting step of secretion is growth phase-independent

When Bacillus subtilis alpha-amylase was expressed under the control of sacR in a degU32(Hy) strain, the production of exoenzyme occurred during both the exponential and stationary phases of growth. In each phase, pulse-chase experiments showed that the rate-limiting step of the secretion process was the release of the processed form of the protein in each physiological context. The rate of this event was slightly slower (t(1/2) = 3.2 min) during the stationary phase than during the exponential phase (t(1/2) = 2 min). The effectors which possibly control the efficiency of the release stage, the level of PrsA or the calcium binding properties of the cell wall, remained unchanged throughout growth phases.     

Somatic polyploidy examined by flow cytometry in Daphnia

Flow cytometry was used to examine the patterns of somatic polyploidyand to determine the haploid genome sizes in Daphnia. The averageproportions of polyploid nuclei among adult animals of D.pulex,D.longispina, D.pulex x D.longispina and D.magna equalled 27,24, 24 and 24%, respectively. Both interclonal and developmentallyregulated variation were observed in the level of somatic polyploidy.Adult animals expressed more extensive polyploidy than did juveniles.The estimates of the haploid genome sizes (C values) of D.pulex,D.longispina, D.pulex x D.longispina and D.magna equalled 0.32,0.27, 0.26 and 0.37 pg, respectively. These are the smallestgenomes reported in crustaceans. Apparently, somatic polyploidycompensates for the loss of genetic material and gives riseto genetic plasticity which may contribute to the considerablelevel of phenotypic plasticity observed in Daphina.     

Blood pressure and five year survival in the very old

During 1977-8 we measured blood pressure in 561 old people (83% of those aged 85 or more living in Tampere) and analysed their five year survival according to their blood pressure group. The subjects were divided into six groups on the basis of their blood pressures (from <120 to >200 mm Hg systolic, from <70 to >110 diastolic). The greatest mortality was observed in those in the lowest systolic and lowest diastolic groups. Mortality was least in subjects with systolic pressures of 160 mm Hg or more and diastolic pressures of 90 mm Hg or more.The most essential finding in this series of the very old was an increased mortality in the lowest blood pressure groups.