SclC is a member of a novel family of collagen-like proteins in Streptococcus equi subspecies equi that are recognised by antibodies against SclC

Previously we have reported on a cell surface collagen-like protein, called SclC, from Streptococcus equi subspecies equi. In the present study we show that this protein is a member of a family of seven collagen-like proteins, called SclC-SclI in this subspecies. All proteins contain an N-terminal signal sequence, followed by a unique non-repetitive region called A, a highly repetitive collagen-like region (CL) consisting of Glycine-Xaa-Yaa-triplet repeats. Following the CL-region a C-terminal proline-rich putative wall spanning region (W) preceding an LPXTG-motif and a hydrophobic transmembrane region (M) are found, typical features of cell surface exposed proteins in Gram-positive bacteria. The nucleotide and amino acid sequences, were analysed to investigate the similarities between them, and recombinant proteins encoding different domains (A- and CL-regions) were expressed and purified. Although the novel collagen-like proteins display differences in amino acid sequences, affinity purified antibodies against SclC were found to cross react with the other members of the novel collagen-like proteins. Furthermore, in sera from horses previously diagnosed having strangles, antibodies against these proteins were detected suggesting that these proteins are expressed during the infection.     

Effects of acidification and liming on carbon and nitrogen mineralization and soil organisms in mor humus

The aim was to determine if changes in C and N mineralization after acidification and liming could be explained by changes in the soil organism biomass. Intact soil cores from F/H layers in a Norway spruce (C:N=31) and a Scots pine (C:N=44) stand in central Sweden were treated in the laboratory for 55 days with deionized water (control), weak H₂SO₄ (successively applied as 72 mm of acid rain of pH 3.1), strong H₂SO₄ (applied as a single high dose of pH 1), and lime CaCO₃. Strong acidification reduced C mineralization and increased net N mineralization in both soils. Weak acidification resulted in similar but less pronounced effects. Liming initially stimulated C mineralization rate, but the rates declined, indicating that an easily available C source was successively used up by the microorganisms. Liming also increased net N mineralization in the C:N=31 humus, but not significantly in the C:N--44 humus. Strong acidification generally affected the amounts of FDA-active fungal hyphae, nematodes and enchytraeids more than the other treatments did. The increases in net N mineralization after acidification and liming could only partly be explained by the decreases in biomass N in soil organisms. Mineralization of biomass N from killed soil organisms could at the most explain up to about 30% of the increase in net N mineralization after strong acidification. Most of the effects on N mineralization seemed to depend on the fact that acidification reduced and liming increased the availability of C and N to the microorganisms. Furthermore, acidification seemed to reduce the incorporation of N from dead organisms into the soil organic matter and, thereby, make the N compounds more readily available to microbial decomposition and mineralization.     

Cost-effectiveness of silvicultural measures to increase substrate availability for red-listed wood-living organisms in Norway spruce forests

It is important that measures to maintain biodiversity are taken in a way that is cost-effective for the landowner. We analyzed the cost-effectiveness of silvicultural measures that aim at increasing the substrate availability for red-listed (species that are threatened, near threatened or where species probably are threatened but data is deficient) saproxylic (wood-inhabiting) organisms. We modelled stands of Norway spruce (Picea abies) in three regions of Sweden by using computer simulations and a database with substrate requirements of saproxylic beetles and cryptogams on the Swedish Red-List. Conclusions concerning cost-effectiveness of silvicultural measures depend on the extinction thresholds of the species they are intended to conserve; measures that generate only small amounts of coarse woody debris (CWD) may provide too little substrate to be useful for species with high extinction thresholds. In northern Sweden, forestland is relatively inexpensive, so a cost-effective strategy to increase the amount of spruce CWD was to set aside more forests as reserves. In central and southern Sweden, more emphasis should instead be given to increasing the amount of CWD in the managed forest. The regulations by the Forest Stewardship Council (FSC) could be made more cost-effective by prescribing creation of more high stumps and retention of larger amounts of naturally dying trees. Large-sized CWD, CWD from slow-growing trees, and CWD in late decay stages are substrate types that were particularly rare in managed forest in relation to unmanaged forests. Manual soil scarification and retention of living trees are measures that can increase the proportion of these underrepresented CWD types.     

Changes in fruitbody production of mycorrhizal and litter decomposing macromycetes in heavy metal polluted coniferous forests in North Sweden

Basidiomycete fruitbodies growing in coniferous forests along a complex heavy metal pollution gradient in north Sweden were identified and counted over a 4 yr period. The dominant metals in the humus layer were As, Cd, Cu, Pb, and Zn. Pb occurred at the highest levels in a range of 80 to 8500 μg g^?1 dry wt. Both the number of fruitbodies and the number of fruiting species decreased strongly with increasing pollution level. A few species appeared to sustain the metal loads. Many of these were ectomycorrhizal fungi. The relationship between fruitbody frequencies and plant species composition were also studied statistically although no obvious relations were found. Metal content of the fruitbodies of six species were also analyzed and their bioaccumulation calculated. Amanita muscaria accumulated Cd efficiently.     

Extraction of rye bran by supercritical carbon dioxide: influence of temperature, CO2, and cosolvent flow rates

Process parameter optimization for the supercritical CO(2) extraction of rye bran to obtain alkylresorcinols (AR) was studied by carrying out a two-level fractional design experiment. Four parameters, temperature, CO(2) flow rate, cosolvent percentage, and extraction time, presumed to influence the extraction process, were analyzed. A tentative fractionation of the crude extract was also carried out and is discussed. The best extracts were achieved when the CO(2) flow rate and extraction time or temperature and cosolvent addition were kept high. It was found that temperature increase was not statistically significant within the range of the study performed, and the extraction time was thus the most important factor. A preliminary fractionation process in two cyclone separators yielded two fractions, one rich in AR components with higher molecular weights and the other rich in AR components with low molecular weight.     

Evaluation of soil respiration characteristics to assess heavy metal effects on soil microorganisms using glutamic acid as a substrate

Computerized continuous monitoring of soil respiration rates before and during glutamic acid decomposition in heavy metal polluted soils was used to determine four microbial parameters: basal respiration rate, substrate induced respiration rate, lag time before the exponential increase of the soil respiration rate and the specific respiration increment during the exponential phase. Both smelter- and laboratory-contaminated soils were studied.

Basal respiration rate was the parameter most inhibited (54–77%) by heavy metal contamination. Increased soil moisture resulted in increased basal respiration rate, irrespective of pollution level. The substrate-induced respiration rate after the addition of glutamic acid was strongly correlated with the basal respiration rate (r = 0.85−0.95). The change in specific respiration increment was not related to metal contamination but increased with increasing soil moisture, with an optimum at about 250% H₂O based on soil organic matter (oven-dried). Lag time was the parameter best correlated with smelter-induced metal contamination (r = 0.64 and 0.75). Unlike the three other parameters, the lag time was unaffected by soil moisture, irrespective of contamination level.