LOCAL ADAPTATION IN A CHANGING WORLD: THE ROLES OF GENE‐FLOW,MUTATION, AND SEXUAL REPRODUCTION

In spatially heterogeneous environments, the processes of gene flow, mutation, and sexual reproduction generate local genetic variation and thus provide material for local adaptation. On the other hand, these processes interchange maladapted for adapted genes and so, in each case, the net influence may be to reduce local adaptation. Previous work has indicated that this is the case in stable populations, yet it is less clear how the factors play out during population growth, and in the face of temporal environmental stochasticity. We address this issue with a spatially explicit, stochastic model. We find that dispersal, mutation, and sexual reproduction can all accelerate local adaptation in growing populations, although their respective roles may depend on the genetic make‐up of the founding population. All three processes reduce local adaptation, however, in the long term, that is when population growth becomes balanced by density‐dependent competition. These relationships are qualitatively maintained, although quantitatively reduced, if the resources are locally ephemeral. Our results suggest that species with high levels of local adaptation within their ranges may not be the same species that harbor potential for rapid local adaptation during population expansion.     

Population density of Sotalia guianensis (Cetacea: Delphinidae) in the Cananéia region, Southeastern Brazil

Population density in cetaceans can be estimated through photo-identification, mark-recapture, land-based observations and visual estimative. We the aim to contribute with conservation strategies, we used line transects (distance method) to estimate the population density of the river dolphin, S. guianensis, in the estuarine region of Cananéia, Southeastern Brazil. The study, developed from May 2003 until April 2004, during dry and rainy seasons and different times of the day, included a sampling area divided into three sectors according to their proximity to the open sea: Sector I (the closest to the open sea); Sector II (with a large flow of fresh water and a salient declivity); and Sector III (with a large flow of fresh water and non salient declivity). Onboard random sampling was carried out in all three sectors, and dolphins seen from the bow to 90 degrees on both port and starboard sides, were registered along with their position and distance from the boat. The total density found was 12.41 ind/km2 (CV = 25.53%) with an average of 2.2 individuals per group for both periods of the day, morning and afternoon. Densities also varied between dry and rainy seasons, being lower in the first with 5.77 ind/km2 (CV = 27.87%) than in the second 20.28 ind/km2 (CV = 31.95%), respectively. Regarding the three sectors, a non-causal heterogeneous distribution was found: Sector I was the most populated (D = 33.10 ind/km2, CV = 13.34%), followed by Sector II (D = 7.8 ind/km2, CV = 21.07%) and Sector III (D = 3.04 ind/km2, CV = 34.04%). The aforementioned area, due to its proximity to the open sea, has the highest salinity level and therefore has the greatest chance of holding most of the marine fish schools which can be cornered by dolphins on high declivity areas during fishing activities. This suggests that food availability may be the most important factor on the river dolphin's distribution in the estuary. Similar studies will contribute to a better understanding of these populations and are essential for future conservation strategies.     

Matrix metalloproteinases in inflammation

Background

Matrix metalloproteinases (MMPs) are a family of ubiquitously expressed zinc-dependent endopeptidases with broad substrate specificity and strictly regulated tissue specific expression. They are expressed in physiological situations and pathological conditions involving inflammation. MMPs regulate several functions related to inflammation including bioavailability and activity of inflammatory cytokines and chemokines. There is also evidence that MMPs regulate inflammation in tumor microenvironment, which plays an important role in cancer progression.

Scope of review

Here, we discuss the current view on the role of MMPs in the regulation of inflammation.

Major conclusions

MMPs modulate inflammation by regulating bioavailability and activity of cytokines, chemokines, and growth factors, as well as integrity of physical tissue barriers. MMPs are also involved in immune evasion of tumor cells and in regulation of inflammation in tumor microenvironment.

General significance

There is increasing evidence for non-matrix substrates of MMPs that are related to regulation of inflammatory processes. New methods have been employed for identification of the substrates of MMPs in inflammatory processes in vivo. Detailed information on the substrates of MMPs may offer more specific and effective ways of inhibiting MMP function by blocking the cleavage site in substrate or by inhibition of the bioactivity of the substrate. It is expected, that more precise information on the MMP–substrate interaction may offer novel strategies for therapeutic intervention in inflammatory diseases and cancer without blocking beneficial actions of MMPs. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.     

Lignification related enzymes in Picea abies suspension cultures

Activity of a number of enzymes related to lignin formation was measured in a Picea abies (L) Karsten suspension culture that is able to produce native-like lignin into the nutrient medium. This cell culture is an attractive model for studying lignin formation, as the process takes place independently of the complex macromolecular matrix of the native apoplast. Suspension culture proteins were fractionated into soluble cellular proteins, ionically and covalently bound cell wall proteins and nutrient medium proteins. The nutrient medium contained up to 5.3% of total coniferyl alcohol peroxidase (EC 1.11.1.7) activity and a significant NADH oxidase activity that is suggested to be responsible for hydrogen peroxide (H2O2) production. There also existed some malate dehydrogenase (EC 1.1.1.37) activity in the apoplast of suspension culture cells (in ionically and covalently bound cell wall protein fractions), possibly for the regeneration of NADH that is needed for peroxidase-catalysed H2O2 production. However, there is no proof of the existence of NADH in the apoplast. Nutrient medium peroxidases could be classified into acidic, slightly basic and highly basic isoenzyme groups by isoelectric focusing. Only acidic peroxidases were found in the covalently bound cell wall protein fraction. Several peroxidase isoenzymes across the whole pI range were detected in the protein fraction ionically bound to cell walls and in the soluble cellular protein fraction. One laccase-like isoenzyme with pI of approximately 8.5 was found in the nutrient medium that was able to form dehydrogenation polymer from coniferyl alcohol in the absence of H2O2. The total activity of this oxidase towards coniferyl alcohol was, however, several orders of magnitude smaller than that of peroxidases in vitro. According to 2D 1H-13C correlation NMR spectra, most of the abundant structural units of native lignin and released suspension culture lignin are present in the oxidase produced dehydrogenation polymer but in somewhat different amounts compared to peroxidase derived synthetic lignin preparations. A coniferin beta-glucosidase (EC 3.2.1.21) was observed to be secreted into the culture medium.     

The evolution and ecology of multiple antipredator defences

Prey seldom rely on a single type of antipredator defence, often using multiple defences to avoid predation. In many cases, selection in different contexts may favour the evolution of multiple defences in a prey. However, a prey may use multiple defences to protect itself during a single predator encounter. Such “defence portfolios” that defend prey against a single instance of predation are distributed across and within successive stages of the predation sequence (encounter, detection, identification, approach (attack), subjugation and consumption). We contend that at present, our understanding of defence portfolio evolution is incomplete, and seen from the fragmentary perspective of specific sensory systems (e.g., visual) or specific types of defences (especially aposematism). In this review, we aim to build a comprehensive framework for conceptualizing the evolution of multiple prey defences, beginning with hypotheses for the evolution of multiple defences in general, and defence portfolios in particular. We then examine idealized models of resource trade-offs and functional interactions between traits, along with evidence supporting them. We find that defence portfolios are constrained by resource allocation to other aspects of life history, as well as functional incompatibilities between different defences. We also find that selection is likely to favour combinations of defences that have synergistic effects on predator behaviour and prey survival. Next, we examine specific aspects of prey ecology, genetics and development, and predator cognition that modify the predictions of current hypotheses or introduce competing hypotheses. We outline schema for gathering data on the distribution of prey defences across species and geography, determining how multiple defences are produced, and testing the proximate mechanisms by which multiple prey defences impact predator behaviour. Adopting these approaches will strengthen our understanding of multiple defensive strategies.     

Molecular characterization and solution properties of enzymatically tailored arabinoxylans

Two α-l-arabinofuranosidases with different substrate specificities were used to modify the arabinose-to-xylose ratio of cereal arabinoxylans: one enzyme (AXH-m) removed the l-arabinofuranosyl substituents from the monosubstituted xylopyranosyl residues and the other (AXH-d3) the (1 → 3)-linked l-arabinofuranosyl units from the disubstituted xylopyranosyl residue. In this study, we noticed that not only the arabinose-to-xylose ratio but also the position of the arabinofuranosyl substituents affects the water-solubility of arabinoxylans. The AXH-d3 treatment had no significant effect on the solution conformation of arabinoxylans, but the density of the arabinoxylan molecules decreased in DMSO solution after AXH-m modification. The possible heterogeneity of arabinoxylans complicated the interpretation of data describing the macromolecular properties of the enzymatically modified samples.     

Fibrous carrot root responses to irrigation and compaction of sandy and organic soils

Field experiments were performed in Southern Finland on fine sand and organic soil in 1990 and 1991 to study carrot roots. Fall ploughed land was loosened by rotary harrowing to a depth of 20 cm or compacted under moist conditions to a depth of 25–30 cm by three passes of adjacent wheel tracks with a tractor weighing 3 Mg, in April were contiguously applied across the plot before seed bed preparation. Sprinkler irrigation (30 mm) was applied to fine sand when moisture in the 0–15 cm range of soil depth was 50% of plant-available water capacity. For root sampling, polyvinyl chloride (PVC) cylinders (30 × 60 cm) were installed in the rows of experimental plots after sowing, and removed at harvest. Six carrot plants were grown in each of in these soil colums in situ in the field.Fine root length and width were quantified by image analysis. Root length density (RLD) per plant was 0.2–1.0 cm cm^-3 in the 0–30 cm range. The fibrous root system of one carrot had total root lengths of 130–150 m in loose fine sand and 180–200 m in compacted fine sand. More roots were observed in irrigated than non-irrigated soils. In the 0–50 cm range of organic soil, 230–250 m of root length were removed from loosened organic soils and 240–300 m from compacted soils. Specific root surface area (surface area divided by dry root weight) of a carrot fibrous root system averaged 1500–2000 cm² g^-1. Root length to weight ratios of 250–350 m g^-1 effectively compare with the ratios of other species.Fibrous root growth was stimulated by soil compaction or irrigation to a depth of 30 cm, in both the fine sand and organic soils, suggesting better soil water supply in compacted than in loosened soils. Soil compaction increased root diameters more in fine sand than it did in organic soil. Most of the root length in loosened soils (fine sand 90%, organic soil 80%) and compacted soils (fine sand 80%, organic soil 75%) was composed of roots with diameters of approximately 0.15 mm. With respect to dry weight, length, surface area and volume of the fibrous root system, all the measurements gave significant resposes to irrigation and soil compaction. Total root volumes in the 0–50 cm of soil were 4.3 cm³ and 9.8 cm³ in loosened fine sand and organic soils, respectively, and 6.7 cm³ and 13.4 cm³ in compacted sand and organic soils, respectively. In fine sand, irrigation increased the volume from 4.8 to 6.3 cm³.     

Activation of Plasmin in Mastitic Milk

Milk and whey samples from healthy and inflamed udder quarters of 10 Ayrshire cows were analyzed for proteolytic activity using radial caseolysis procedures, a fluorogenic coumaryl peptide substrate, and casein agarose zymography. Free lysosomal enzyme activity (N–acetyl–beta–D–glucosaminidase) was used as the criterion for inflammation. All mastitic milk samples had proteolytic activity, tentatively identified as plasmin (comigration at Mr 83 000 and characteristic fragmentation). The plasmin activities in mastitic milk were on average 2.9 μg/ml (range 0.5–12.5) as measured by radial caseolysis. Milk or whey specimens from healthy quarters were all negative except 1 in which an activity of 0.1 μg/ml was found in both specimens. The caseolytic activities were totally inhibited by 50 KITJ/ml of aprotinin, a serine proteinase inhibitor from bovine lung. No free plasminogen activator (PA) activity was found in any of the samples. Howewer, according to zymographic analyses PA molecules corresponding to urokinase were found in healthy and especially in mastitic specimens. Analysis of plasmin may provide an alternative means of screening for mastitic milk samples.     

Oxidative d-xylose metabolism of Gluconobacter oxydans

Summary Gluconobacter oxydans subsp. suboxydans ATCC 621 oxidizes d-xylose to xylonic acid very efficiently, although it cannot grow on xylose as sole carbon source. The oxidation of xylose was found to be catalyzed by a membrane-bound xylose dehydrogenase. The xylono--lactone formed in the oxidation reaction is subsequently hydrolyzed to xylonic acid by a -lactonase. The complete oxidation pathway of d-xylose in G. oxydans is evidently located in the periplasmic space.     

Mycological records from ISAM 9, Kevo,Finland

ISAM 9 (International Symposium of Arctic-Alpine Mycology) was held in August 2012?at the Kevo Lapland Research Station in Utsjoki in northernmost Finnish Lapland. In addition to Utsjoki, some excursions were made in Finnmark, the northernmost part of Norway. Kevo station lies in the subarctic zone characterized by mountain birch (Betula pubescens var. czerepanovii), but the fells reach the arctic tundra zone. Áilegas fells at Utsjoki village and at Nuvvus lie on acid ground as does Skalluvaara, and all are under influence of reindeer grazing. The Gistuskaidi fell is highest and is characterized by the presence of more basic rocks; the vegetation also reflects some amount of maritime influence. The places visited on the Norwegian side belong to the Nesseby commune at the sea shore and Tana commune on the shore of the Tana River and along the road to Båtsfjord where the tundra is maritime and mossy with calcareous spots. In all 123 taxa were found during the excursions, some of them not determined at species level. The reported fungal taxa belong to the Basidiomycota (115 taxa), Ascomycota (7 taxa), and Mycetozoa (1 taxon).