Changes in phenolic composition induced by Pseudomonas savastanoi pv. Savastanoi infection in olive tree: presence of large amounts of verbascoside in nodules of tuberculosis disease

A study was carried out to determine the changes in phenolic composition induced by tuberculosis infection in olive trees. Four ethanolic extracts were compared: olive leaf from shoots affected by Pseudomonas savastanoi pv. Savastanoi, nodules induced by this bacteria, leaf from healthy (asymptomatic) shoots, and shoots. Among the differences found, the presence of a phenolic compound in nodules was significant in much larger quantities than in leaf or shoots. Mass spectrometric analysis showed this compound to be verbascoside. The enhancement of its biosynthesis could be related to the defense mechanisms of the tree in the nodules induced by P. savastanoi and suggests the possibility of exploration of natural and biotechnological sources of this compound.     

Changes in local species richness of farmland birds in relation to land-use changes and landscape structure

It has been suggested that an increase in the area of low-intensity land-use on arable land (e.g. set-aside fields and short-rotation coppice), and high or increased farmland habitat heterogeneity, may halt or reverse the observed population decline of farmland birds. We tested these hypotheses by undertaking farmland bird censuses during two contrasting periods of agricultural policies and land-use (i.e. 1994 and 2004) in a farmland region covering a gradient of forest- to farmland-dominated landscapes in Sweden. Local species richness (i.e. at 3 hectare sites) declined significantly between 1994 and 2004. Local species richness was positively related to habitat heterogeneity in both years of study whereas temporal change in species richness was not. Local change in species richness was positively associated with a change in the proportion of non-rotational set aside and short-rotation coppice (i.e. low-intensity land-use forms), but also to changes in the amount of spring-sown crops. However, the effect of low-intensity land-use was significantly dependent on the amount of forest in the surrounding landscape. An increase in low-intensity land-use was linked to an increase (or less marked decrease) in species richness at sites located in open farmland surroundings but to a decrease in richness at sites located in forest surroundings. This interaction between amount of forest and low-intensity land-use could be interpreted as a “rare habitat effect”, where an increase in a farmland habitat only positively affects biodiversity when it was originally uncommon (i.e. open farmland areas). Our results suggest that conservation measures of farmland biodiversity have to be put in a landscape context.     

Working with Swedish cryptogam conservation

The cryptogams constitute a very species-rich group. However, only a few taxa are well-studied and we thus know very little about the majority of the species. Moreover, cryptogams are usually small and hard to identify without training. The lack of knowledge is problematic to the conservation of cryptogams. Without basic information on actual distribution, population sizes and trends, susceptibility to anthropogenic environmental changes, etc., our ability to develop efficient conservation measures is put at risk. The necessity of additional research in, for example, taxonomy, population biology is clearly evident. In addition to better basic information, we also need more cryptogam experts, as well as good handbooks and identification keys. The level of cryptogam knowledge in Europe is, however, higher than in most other parts of the world. This presentation reviews the situation in Sweden, focusing on the red listing process and the ongoing publication of illustrated cryptogam floras.     

L-tryptophan reacts with naturally occurring and food-occurring phenolic aldehydes to give phenolic tetrahydro-beta-carboline alkaloids: activity as antioxidants and free radical scavengers

The reaction between the essential amino acid l-tryptophan and flavoring or naturally occurring phenyl and phenolic aldehydes was studied, and the alkaloidal reaction products were characterized by NMR and HPLC-MS. Benzaldehyde, vanillin, syringaldehyde, salicylaldehyde, and anisaldehyde condensed with l-tryptophan in aqueous-acidic media affording the corresponding phenolic tetrahydro-beta-carboline-3-carboxylic acid as two diastereoisomers, 1S,3S-cis and 1R,3S-trans. With the exception of benzaldehyde, the rest of the aldehydes needed heating conditions (70 degrees C) to significantly form tetrahydro-beta-carbolines over time with the cyclization highly favored at low pH. This suggests a likely formation of these compounds under conditions that may occur in foods, food processing, or cooking. The new phenolic tetrahydro-beta-carboline alkaloids were assayed, for the first time, for their activity as free radical scavengers and antioxidants and showed good antioxidant properties with Trolox equivalent antioxidant capacity (TEAC) values much higher than those of ascorbic acid and the water soluble vitamin E analogue, Trolox, in the 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) assay.     

Soil and crop responses to controlled traffic farming in reduced tillage and no-till: some experiences from field experiments and on-farm studies in Sweden

ABSTRACT

The purpose of this study was to investigate the impact of controlled traffic farming (CTF) with respect to soil physical properties and crop yield for Swedish conditions. Three field trials were conducted for six growing seasons in central and southern Sweden. In two of the trials, we compared CTF with random traffic farming (RTF) in deep chiseling (DC, 15–20?cm), shallow cultivation (SC, 5–10?cm) and no-till. The third trial was on farm study by using the existing CTF module at the farm. In the tracks of CTF (traffic zone) dry bulk density was increased and water movement was decreased. Soil penetration resistance was greater in the traffic zone than in the crop zone in some of the trials but the difference was not statistically significant. On average, crop yield was similar between CTF and RTF for all trials. Yield in the traffic zone was significantly less than that in the crop zone in the on-farm trial, but the yield in both zones were similar in the field trial at Lönnstorp, south Sweden. On the contrary, in the field trial at Säby 1 in Uppsala, central Sweden, crop zone produced less yield than traffic zone probably because of too loose soil, which impaired the uptake of nutrients and water. We conclude that if vehicle weight is not very high and the soil is not vulnerable to compaction, dual wheels and CTF are equal options.     

Genetic structure, population dynamics, and conservation of Black caiman (Melanosuchus niger)

Microsatellite DNA polymorphisms were screened in seven populations of the largest Neotropical predator, the Black caiman Melanosuchus niger (n = 169), originating from Brazil, French Guiana and Ecuador. Eight loci were used, for a total of 62 alleles. The Ecuadorian population had the lowest number of alleles, heterozygosity and gene diversity; populations of the Guianas region exhibited intermediate diversities; highest values were recorded in the two populations of the Amazon and Rio Negro. During the last century Melanosuchus populations have been reduced to 1-10% of their initial levels because of hunting pressure, but no strong loss of genetic diversity was observed. Both the inter-locus g-test and the Pk distribution suggested no recent important recovery and/or expansion of current populations. On a global scale, the inter-population variation of alleles indicated strong differentiation (F_ST = 0.137).Populations were significantly isolated from each other, with rather limited gene flow; however, these gene flow levels are sufficiently high for recolonization processes to effectively act at regional scales. In French Guiana, genetic structuring is observed between populations of two geographically close but ecologically distinct habitats, an estuary and a swamp. Similar divergence is observed in Brazil between geographically proximate “black water” and “white water” populations. As a consequence, the conservation strategy of the Black caiman should include adequate ecosystem management, with strong attention to preservation of habitat integrity. Distribution of genetic diversity suggests that current populations originated from the central Amazonian region. Dispersal of the species may thus have been deeply influenced by major climatic changes during the Holocene/Pleistocene period, when the Amazonian hydrographic networks were altered. Major ecological changes such as glaciations, marine transgressions and a hypothesized presence of an Amazonian Lake could have resulted in extension of Black caiman habitats followed by isolation.     

In-depth mechanistic study on the formation of acrylamide and other vinylogous compounds by the maillard reaction

The formation of acrylamide was studied in low-moisture Maillard model systems (180 degrees C, 5 min) based on asparagine, reducing sugars, Maillard intermediates, and sugar degradation products. We show evidence that certain glycoconjugates play a major role in acrylamide formation. The N-glycosyl of asparagine generated about 2.4 mmol/mol acrylamide, compared to 0.1-0.2 mmol/mol obtained with alpha-dicarbonyls and the Amadori compound of asparagine. 3-Hydroxypropanamide, the Strecker alcohol of asparagine, generated only low amounts of acrylamide ( approximately 0.23 mmol/mol), while hydroxyacetone increased the acrylamide yields to more than 4 mmol/mol, indicating that alpha-hydroxy carbonyls are much more efficient than alpha-dicarbonyls in converting asparagine into acrylamide. The experimental results are consistent with the reaction mechanism based on (i) a Strecker type degradation of the Schiff base leading to azomethine ylides, followed by (ii) a beta-elimination reaction of the decarboxylated Amadori compound to afford acrylamide. The beta-position on both sides of the nitrogen atom is crucial. Rearrangement of the azomethine ylide to the decarboxylated Amadori compound is the key step, which is favored if the carbonyl moiety contains a hydroxyl group in beta-position to the nitrogen atom. The beta-elimination step in the amino acid moiety was demonstrated by reacting under low moisture conditions decarboxylated model Amadori compounds obtained by synthesis. The corresponding vinylogous compounds were only generated if a beta-proton was available, for example, styrene from the decarboxylated Amadori compound of phenylalanine. Therefore, it is suggested that this thermal pathway may be common to other amino acids, resulting under certain conditions in their respective vinylogous reaction products.     

Artificial dispersal of endangered epiphytic lichens: a tool for conservation in boreal forest landscapes

Due to increasing fragmentation of the boreal forests of Fennoscandia, a number of epiphytic lichens are now becoming threatened. Since these species typically are limited by a poor ability of dispersal, one possible but largely unexplored strategy for conservation is to disperse lichen material artificially into suitable habitats. Therefore, the objective of this study was to evaluate survival and vitality in lichen fragments from Evernia divaricata (L.) Ach. and Ramalina dilacerata (Hoffm.) Hoffm. after transplantation into three different stand types situated in northern Sweden, using different fragment sizes and modes of transplantation. After one year, survival ranged between 85% and 97.5%, and new growth occurred at all transplantation sites. The study has shown that transplantations of small fragments might constitute a resource-efficient option for establishment of new populations of endangered lichen species, or for enlarging their populations at the present sites of occurrence. In addition, the mode of transplantation was of importance for fragment vitality.     

Diversity in natural populations of wild Brassica oleracea as estimated by isozyme and RAPD analysis

Naturally occurring populations of wild Brassica oleracea were collected in Spain, France, and Great Britain. Allele frequencies at four isozyme loci were determined for 18 populations, while five populations were screened using five random primers to generate RAPDs. Levels of homozygosity and gene diversity, H, were computed for each population using isozyme data and RAPD data when applicable. Homozygosity levels tended to be higher in smaller populations, which could also be observed as increased numbers of homozygous loci in smaller populations. Gene diversity values based on isozymes indicated considerable within population variation regardless of population size. The RAPID based gene diversities were significantly higher and the two exceptional populations displayed diversity levels more in keeping with the rest. The coefficient of gene differentiation, G _ST , for populations in each region showed that the Spanish populations were more homogenous than the French or British. When the G _ST for all populations was calculated using isozymes vs. RAPD data, the RAPD data gave a significantly lower value, a plausible result of the higher within population variation detected using RAPDs. Genetic distances between populations from different regions were also calculated from both data sets and used to produce phenograms. Clustering according to geographic region was not evident using either isozyme or RAPD data.