Morphological variability in the ecotone — an important factor for the conservation of fish species richness in Swiss rivers

Data from a survey on the distribution of fish species in Switzerland were used to test the hypothesis that species richness of the fish fauna is closely related with the structure, heterogeneity and complexity of the ecotonal zone in rivers. Species richness increased with increasing structural heterogeneity and variability of the ecotone in rivers wider than 2.5 m at altitudes below 500 m. In lowland brooks and in rivers at higher altitudes other factors seemed to be more important than morphological variability: alpine rivers are more often left natural than lowland rivers and salmonid stocking is more important in these naturally species poor fish communities. The proportion of threatened species was higher if riverbed and -banks were natural, the slope was flat, the variability in depths and sediment composition was high and if the ecotonal zone was well structured. Specialized species such as nase and riffle minnow only occurred in larger rivers, whereas in small and medium-sized rivers with low morphological variability these threatened species were missing. On the other hand, ubiquitous species such as chub, roach and perch, occurred in all sizes of rivers, even if morphological variability was small. Low morphological variability and its impact on the composition of the fish community is mainly a consequence of past human interventions. Therefore river management has to take into account the ecological requirements of specialized species and increasing the variability of riverbed and banks would considerably contribute to the conservation of endangered fish species.     

The role of the copper-binding enzyme – laccase – in the biodegradation of polyethylene by the actinomycete Rhodococcus ruber

Polyethylene is considered one of the most durable plastic polymers. Virtually, non-biodegradable polyethylene accumulates in the environment, thus posing an ecological threat to man and wildlife. We have previously isolated a strain of the actinomycete Rhodococcus ruber (designated C208; EC 1.10.3.2.) capable of utilizing and degrading polyethylene. Here, we report the role of the bacterial copper-binding enzyme, laccase, in the oxidation and degradation of polyethylene by this strain. Copper markedly affected the induction and activity of laccase, resulting in polyethylene degradation. mRNA quantification by RT-PCR, revealed a 13-fold increase in laccase mRNA levels, in copper-treated cultures compared with the untreated control. Addition of copper to C208 cultures containing polyethylene enhanced the biodegradation of polyethylene by 75%, as compared with the non-amended control. Furthermore, when an extracellular isoform of laccase collected from the media of copper-induced cells was incubated with polyethylene, reductions of 20% and 15% were obtained in the Average Molecular Weight (Mw) and Average Molecular Number (Mn) with the polymer, respectively. FTIR analysis of similar polyethylene films incubated with the extracellular laccase exhibited an increase in the carbonyl peak, indicating that enzymatic oxidation by laccase plays a major role in the biodegradation of polyethylene.     

A nature reserve as a repository of genetic richness – The case of European larch from the Gorce Mountains

Conservation of valuable populations must be based on a thorough understanding of their genetic variation, especially for species negatively affected by human activities. We investigated the population of larch from the nature reserve in the Gorce Mountains, which was established to preserve a unique stand of Larix decidua subsp. polonica, a remnant of one of the largest native complexes of this species. The chloroplast marker ll-TaqI was used to investigate whether the gene pool of the analysed population was contaminated with the alien larch species. We used eleven nuclear DNA microsatellite markers (nSSRs) to examine this population’s genetic diversity and verify the hypothesis about historical use of the larch from the reserve as a source of reproductive material for the Tatra Mountains. The link between the reserve population and the European larch’s ancestral groups was also verified. No contamination of the studied pool of individuals by alien species was found. The study showed high genetic variability in larch from the Gorce Mountains (H_E = 0.689, H_O = 0.671). The differentiation between the Gorce and Tatra National Park populations was F_ST = 0.038 (p < 0.001). Trees from the reserve and the national park formed two distinct genetic groups. We rejected the hypothesis that the nature reserve was the source of the regeneration material used in the Tatra Mountains. The study proved the uniqueness of the reserve population, and confirmed the appropriateness of the protection measures taken.     

The Contributions – and Collapse – of Lamarckian Heredity in Pasteurian Molecular Biology: 1. Lysogeny, 1900–1960

This article shows how Lamarckism was essential in the birth of the French school of molecular biology. We argue that the concept of inheritance of acquired characters positively shaped debates surrounding bacteriophagy and lysogeny in the Pasteurian tradition during the interwar period. During this period the typical Lamarckian account of heredity treated it as the continuation of protoplasmic physiology in daughter cells. Félix d’Hérelle applied this conception to argue that there was only one species of bacteriophage and Jules Bordet applied it to develop an account of bacteriophagy as a transmissible form of autolysis and to analyze the new phenomenon of lysogeny. In a long-standing controversy with Bordet, Eugène Wollman deployed a more morphological understanding of the inheritance of acquired characters, yielding a particulate, but still Lamarckian, account of lysogeny. We then turn to André Lwoff who, with several colleagues, completed Wollman’s research program from 1949 to 1953. We examine how he gradually set aside the Lamarckian background, finally removing inheritance of acquired characters from the resulting account of bacteriophagy and lysogeny. In the conclusion, we emphasize the complex dual role of Lamarckism as it moved from an assumed explanatory framework to a challenge that the nascent molecular biology had to overcome.     

Species introduction in restoration projects – Evaluation of different techniques for the establishment of semi-natural grasslands in Central and Northwestern Europe

During recent decades, many studies have shown that the successful restoration of species-rich grasslands is often seed-limited because of depleted seed banks and limited seed dispersal in modern fragmented landscapes. In Europe, commercial seed mixtures, which are widely used for restoration measures, mostly consist of species and varieties of non-local provenance. The regional biodiversity of a given landscape, however, can be preserved only when seeds or plants of local provenance are used in restoration projects. Furthermore, the transfer of suitable target species of local provenance can strongly enhance restoration success.We review and evaluate the success of currently used near-natural methods for the introduction of target plant species (e.g. seeding of site-specific seed mixtures, transfer of fresh seed-containing hay, vacuum harvesting, transfer of turves or seed-containing soil) on restoration sites, ranging from dry and mesic meadows to floodplain grasslands and fens. Own data combined with literature findings show species establishment rates during the initial phase as well as the persistence of target species during long-term vegetation development on restoration sites.In conclusion, our review indicates that seed limitation can be overcome successfully by most of the reviewed measures for species introduction. The establishment of species-rich grasslands is most successful when seeds, seed-containing plant material or soil are spread on bare soil of ex-arable fields after tilling or topsoil removal, or on raw soils, e.g. in mined areas. In species-poor grasslands without soil disturbance and on older ex-arable fields with dense weed vegetation, final transfer rates were the lowest. For future restoration projects, suitable measures have to be chosen carefully from case to case as they differ considerably in costs and logistic effort. Long-term prospects for restored grassland are especially good when management can be incorporated in agricultural systems.     

Trade-offs between plant species richness and carbon storage in the context of afforestation – Examples from afforestation scenarios in the Mulde Basin,Germany

The German Federal State of Saxony aims to increase forest cover, supported by the implementation of afforestation programs. To analyze consequences of an increase in forest cover, this study investigates possible trade-offs between carbon storage and plant biodiversity caused by afforestation. Six afforestation scenarios with total forest cover ranging from 27.7% to 46% were generated in the Mulde river basin in Saxony with regard to different forest types. Carbon storage was calculated by the process-based Dynamic Vegetation Model LPJ-GUESS while random forest models were used to predict changes in plant species richness. We used eight different plant groups as responses: total number of plant species, endangered species, as well as species grouped by native status (three groups) and pollination traits (three groups). Afforestation led to an increase in carbon storage that was slightly stronger in coniferous forests as compared to deciduous forests. The relationship between plant species richness and afforestation was context dependent. Species richness showed a non-linear relationship with forest cover share. The relationship was influenced by shares of land use types, climatic conditions and land use configuration expressed by the number of land use patches. The effect of forest type on plant species richness was marginal. On average the relationship between carbon storage and plant species richness was synergistic for most plant groups. However, the relationship between change in species richness and change in carbon storage varied across space. This changing relationship was used to identify priority areas for afforestation. The different plant groups responded differently to an increase in forest cover. The change in species richness for Red List species was relatively distinct from the other species groups. Neophytes and archeophytes (i.e. alien plant species introduced after and before the discovery of the Americas) showed a similar response to the afforestation scenarios. While afforestation had overall positive effects both on plant species richness and carbon storage, a number of locations were identified for which afforestation would lead to a decrease in plant species richness. Spatial planning should therefore avoid afforestation at these locations.     

The impact of roads on the avifauna of páramo grasslands in Cajas National Park,Ecuador

National parks are an important tool for conserving biodiversity, particularly in areas of high biodiversity and endemism such as the tropical Andes. However, national parks often face a variety of stressors related to recreation, road construction and illegal extraction of natural resources. Unfortunately, the influence of these stressors for biodiversity is rarely well documented. Cajas National Park in Ecuador is no exception. Despite being traversed by the Cuenca-Molleturo-Naranjal road, effects of the road construction on biodiversity have not been determined. We therefore assessed the influence of road proximity on bird species richness and abundance as well as composition of bird habitat groups in Cajas National Park using transect walks at 25 m and 250 m distance to the road (overall 18 transects, each 1 km length). In total, we recorded 1110 individuals of 28 páramo bird species. Overall species richness did not differ between transects near and far from the road. Nevertheless, the average abundance of shrubby páramo species was significantly higher far from the road than near the road (Far = 36, Near = 25). Moreover, we found a tendency towards differences in the composition of bird habitat groups between transects near and far from the road. One aspect potentially driving the observed patterns was the increasing proportion of planted non-native woody tree species within páramo grassland near the road, which may have caused reduced abundances of shrubby páramo bird species there. While roads represented a clear impact on the composition of bird species in the páramo, the major effect seems to be driven by the introduction of non-native plant species along the roadside. In order to reduce the impact of roads to a minimum, we suggest that park managers should control the introduction of such plant species.     

The singular fate of genetics in the history of French biology, 1900–1940

In this study we have examined the reception of Mendelism in France from 1900 to 1940, and the place of some of the extra-Mendelian traditions of research that contributed to the development of genetics in France after World War II. Our major findings are:

Humidity – The overlooked variable in the thermal biology of mosquito-borne disease

Vector-borne diseases cause significant financial and human loss, with billions of dollars spent on control. Arthropod vectors experience a complex suite of environmental factors that affect fitness, population growth and species interactions across multiple spatial and temporal scales. Temperature and water availability are two of the most important abiotic variables influencing their distributions and abundances. While extensive research on temperature exists, the influence of humidity on vector and pathogen parameters affecting disease dynamics are less understood. Humidity is often underemphasized, and when considered, is often treated as independent of temperature even though desiccation likely contributes to declines in trait performance at warmer temperatures. This Perspectives explores how humidity shapes the thermal performance of mosquito-borne pathogen transmission. We summarize what is known about its effects and propose a conceptual model for how temperature and humidity interact to shape the range of temperatures across which mosquitoes persist and achieve high transmission potential. We discuss how failing to account for these interactions hinders efforts to forecast transmission dynamics and respond to epidemics of mosquito-borne infections. We outline future research areas that will ground the effects of humidity on the thermal biology of pathogen transmission in a theoretical and empirical framework to improve spatial and temporal prediction of vector-borne pathogen transmission.     

The pH dependence of the stereochemistry around the heme group in NO–cytochrome c (horse heart)

The electronic absorption, EPR and MCD spectra of NO derivatives of both ferrous and ferric cytochrome c (horse heart) have been measured in the pH region 2.0 to 12.9, in order to elucidate the pH dependence of the stereochemistry around the heme group. The reaction products of NO with ferrous cytochrome c in equilibrium were as follows: in the region 2.0 ⩽ pH ⩽ 5.3, NO–ferrous cytochrome c; in the region 5.3 < pH ⩽ 11.0, a mixture of NO–ferrous cytochrome c and native ferrous cytochrome c; at pH 12.0, NO–ferrous cytochrome c. At pH 2.0, the NO–ferrous cytochrome c contained a five-coordinate nitrosylheme as the major component and a six-coordinate species as the minor component, and at the order pH values it contained only the six-coordinate species. The reaction products of NO with ferric cytochrome c in equilibrium were as follows: in the region 2.0 ⩽ pH ⩽ 7.2, NO–ferric cytochrome c with six-coordinate nitrosylheme; in the region 7.2 < pH ⩽ 11.0, a mixture of NO–ferrous cytochrome c and native ferrous cytochrome c; at pH 12.0, NO–ferrous cytochrome c. Thus, the reaction of NO with ferric cytochrome c results in the formation of NO–ferrous cytochrome c, which is a typical case of reductive nitrosylation.     

The decline of malaria in Finland – the impact of the vector and social variables

Background

Resistance to anti-malarial drugs hampers control efforts and increases the risk of morbidity and mortality from malaria. The efficacy of standard therapies for uncomplicated Plasmodium falciparum and Plasmodium vivax malaria was assessed in Chumkiri, Kampot Province, Cambodia.

Methods

One hundred fifty-one subjects with uncomplicated falciparum malaria received directly observed therapy with 12 mg/kg artesunate (over three days) and 25 mg/kg mefloquine, up to a maximum dose of 600 mg artesunate/1,000 mg mefloquine. One hundred nine subjects with uncomplicated vivax malaria received a total of 25 mg/kg chloroquine, up to a maximum dose of 1,500 mg, over three days. Subjects were followed for 42 days or until recurrent parasitaemia was observed. For P. falciparum infected subjects, PCR genotyping of msp1, msp2, and glurp was used to distinguish treatment failures from new infections. Treatment failure rates at days 28 and 42 were analyzed using both per protocol and Kaplan-Meier survival analysis. Real Time PCR was used to measure the copy number of the pfmdr1 gene and standard 48-hour isotopic hypoxanthine incorporation assays were used to measure IC₅₀ for anti-malarial drugs.

Results

Among P. falciparum infected subjects, 47.0% were still parasitemic on day 2 and 11.3% on day 3. The PCR corrected treatment failure rates determined by survival analysis at 28 and 42 days were 13.1% and 18.8%, respectively. Treatment failure was associated with increased pfmdr1 copy number, higher initial parasitaemia, higher mefloquine IC₅₀, and longer time to parasite clearance. One P. falciparum isolate, from a treatment failure, had markedly elevated IC₅₀ for both mefloquine (130 nM) and artesunate (6.7 nM). Among P. vivax infected subjects, 42.1% suffered recurrent P. vivax parasitaemia. None acquired new P. falciparum infection.

Conclusion

The results suggest that artesunate-mefloquine combination therapy is beginning to fail in southern Cambodia and that resistance is not confined to the provinces at the Thai-Cambodian border. It is unclear whether the treatment failures are due solely to mefloquine resistance or to artesunate resistance as well. The findings of delayed clearance times and elevated artesunate IC₅₀ suggest that artesunate resistance may be emerging on a background of mefloquine resistance.     

Up in the Tree – The Overlooked Richness of Bryophytes and Lichens in Tree Crowns

Assessing diversity is among the major tasks in ecology and conservation science. In ecological and conservation studies, epiphytic cryptogams are usually sampled up to accessible heights in forests. Thus, their diversity, especially of canopy specialists, likely is underestimated. If the proportion of those species differs among forest types, plot-based diversity assessments are biased and may result in misleading conservation recommendations. We sampled bryophytes and lichens in 30 forest plots of 20 m × 20 m in three German regions, considering all substrates, and including epiphytic litter fall. First, the sampling of epiphytic species was restricted to the lower 2 m of trees and shrubs. Then, on one representative tree per plot, we additionally recorded epiphytic species in the crown, using tree climbing techniques. Per tree, on average 54% of lichen and 20% of bryophyte species were overlooked if the crown was not been included. After sampling all substrates per plot, including the bark of all shrubs and trees, still 38% of the lichen and 4% of the bryophyte species were overlooked if the tree crown of the sampled tree was not included. The number of overlooked lichen species varied strongly among regions. Furthermore, the number of overlooked bryophyte and lichen species per plot was higher in European beech than in coniferous stands and increased with increasing diameter at breast height of the sampled tree. Thus, our results indicate a bias of comparative studies which might have led to misleading conservation recommendations of plot-based diversity assessments.     

The effects of reindeer grazing on the composition and species richness of vegetation in forest–tundra ecotone

We conducted an 8-year exclosure experiment (1999–2006) in a forest–tundra ecotonal area in northwestern Finnish Lapland to study the effects of reindeer grazing on vegetation in habitats of variable productivity and microhabitat structure. The experimental sites included tundra heath, frost heath and riparian habitats, and the two latter habitats were characterized by hummock-hollow ground forms. The total cover of vegetation, cover of willow (Salix spp.), dwarf birch (Betula nana), dwarf shrubs, forbs and grasses (Poaceae spp.) increased in exclosures in all habitats. The increase in the total cover of vegetation and in the covers of willow and dwarf birch tended to be greatest in the least productive tundra heath. Opposing to the increase in the dominant vascular plant groups, the cover and species number of bryophytes decreased in exclosures. We conclude that the effects of reindeer grazing on vegetation composition depend on environmental heterogeneity and the responses vary among plant groups. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The Distribution of Tissue Insulin Receptors in the Mouse by Whole – Body Autoradiography

Abstract

The distribution of insulin binding sites in the mouse was investigated by in vivo whole – body autoradiography. Male mice were injected intravenousely with ¹²⁵ I – insulin in the absence of and, in the presence of, excess unlabeled insulin. Three, 6, 15, 30 and 60 minutes after injection, the animals were perfused and subjected to autoradiographic procedures.

Specific insulin binding was observed in the choroid plexus, liver, gastrointestinal tract, spleen, pancreas, deferent duct, and Harderian gland.

In the liver and spleen, the distribution of binding sites was heterogeneous. In the liver, the density of the binding was higher around the branches of the portal vein than around the central vein. In the spleen, the marginal zone exhibited a higher density than the white and red pulp.

The kidney cortex, and the thyroid gland showed a high degree of insulin binding, but the binding was nonspecific. The binding of insulin to other tissues and organs, including the skeletal muscle and fat, was weak, and most of the binding was nonspecific.     

The National QAAMS Program – A Practical Example of PoCT Working in the Community

The Quality Assurance for Aboriginal and Torres Strait Islander Medical Services (QAAMS) Program is the largest and longest-standing national point-of-care testing (PoCT) program in Australia. With a focus on PoCT for diabetes management, it now operates in 115 Indigenous medical services and has been funded continuously by the Australian Government for 11 years. A recent independent evaluation of the QAAMS Program concluded that the program continues to meet best practice standards for Indigenous healthcare, diabetes management and PoCT.     

The missing link in the amyloid cascade of Alzheimer’s disease – Metal ions

Progressive deposition of amyloid beta (Aβ) peptides into amyloid plaques is the pathological hallmark of Alzheimer’s disease (AD). The amyloid cascade hypothesis pins this deposition as the primary cause of the disease, but the mechanisms that causes this deposition remain elusive. An increasing amount of evidence shows that biometals Zn(II) and Cu(II) can interact with Aβ, thus influencing the fibrillization and toxicity. This review focuses on the role of Zn(II) and Cu(II) in AD, and revisits the amyloid cascade hypothesis demonstrating the possible roles of Zn(II) and Cu(II) in the disease pathogenesis.