The genus (Lamiaceae) in Central Africa (Democratic Republic of the Congo, Rwanda, Burundi), with the description of 15 new species.

The genus is revised for DR. Congo, Rwanda, Burundi, based on herbarium taxonomy. Ninety-five taxa are reported (89 species, 1 subspecies, 5 varieties).

Exploring the floristic diversity of tropical Africa.

Background: Understanding the patterns of biodiversity distribution and what influences them is a fundamental pre-requisite for effective conservation and sustainable utilisation of biodiversity. Such knowledge is increasingly urgent as biodiversity responds to the ongoing effects of global climate change. Nowhere is this more acute than in species-rich tropical Africa, where so little is known about plant diversity and its distribution.

RAINBIO: a mega-database of tropical African vascular plants distributions.

The tropical vegetation of Africa is characterized by high levels of species diversity but is undergoing important shifts in response to ongoing climate change and increasing anthropogenic pressures. Although our knowledge of plant species distribution patterns in the African tropics has been improving over the years, it remains limited. Here we present RAINBIO, a unique comprehensive mega-database of georeferenced records for vascular plants in continental tropical Africa.

Copper and cobalt accumulation in plants: a critical assessment of the current state of knowledge.

This review synthesizes contemporary understanding of copper-cobalt (Cu-Co) tolerance and accumulation in plants. Accumulation of foliar Cu and Co to > 300 μg g is exceptionally rare globally, and known principally from the Copperbelt of Central Africa. Cobalt accumulation is also observed in a limited number of nickel (Ni) hyperaccumulator plants occurring on ultramafic soils around the world.

Multiscale assemblage of an ectomycorrhizal fungal community: the influence of host functional traits and soil properties in a 10-ha miombo forest.

Ectomycorrhizal fungi (EMF) are highly diversified and dominant in a number of forest ecosystems. Nevertheless, their scales of spatial distribution and the underlying ecological processes remain poorly understood. Although most EMF are considered to be generalists regarding host identity, a preference toward functional strategies of host trees has never been tested.

Copper and cobalt mobility in soil and accumulation in a metallophyte as influenced by experimental manipulation of soil chemical factors.

The influence of Fe oxides, Mn oxides and organic matter (OM) on the Cu and Co mobility in soil and accumulation in the metallophyte Anisopappus chinensis (Ac), as compared with Helianthus annuus (Ha), was experimentally investigated. Growth and accumulation response when increasing the exchangeable Cu and Co concentrations in soil were also investigated. Plants were cultivated on soil where concentrations of Cu, Co, Fe oxides, Mn oxides and OM content were varied according to 36 treatments.

Unusual outcome of in utero infection and subsequent postnatal super-infection with different PCV2b strains.

VC2002, isolated from postweaning multisystemic wasting syndrome (PMWS)-affected pig, is a mixture of two porcine circovirus genotype 2b (PCV2b) viruses, K2 and K39. Preliminary experiments disclosed short-term adverse effects of K39, but not K2, on porcine foetuses. These findings led to the hypothesis that infection of immuno-incompetent foetuses with K2 confers a status of immunotolerance, and postnatal super-infection with K39 triggers PMWS.

Cell tropism and entry of porcine circovirus 2.

Porcine circovirus 2 (PCV2) may induce reproductive failure (return to oestrus, embryonic death, mummification, weak- and stillborn piglets) and postweaning multisystemic wasting syndrome (PMWS). Furthermore, it may modulate the immunity in such a way that it aggravates the outcome of many bacterial and viral infections. In the present paper, the cellular tropism and entry of PCV2 are described and linked with the pathological and clinical consequences.

Phytostabilisation of copper-contaminated soil in Katanga: an experiment with three native grasses and two amendments.

This study evaluates the feasibility of using the grass species Rendlia altera, Monocymbium ceresiiforme, Cynodon dactylon, and amendments (compost and lime) for the phytostabilisation of soils contaminated by Cu in the province of Katanga (Democratic Republic of Congo). Species were grown on control and Cu-contaminated plots (artificially contaminated with 2,500 mg kg(-1) Cu) unamended (NA), amended with 4.5 kg compost m(-2) or 0.

Life history traits of the pseudometallophyte Thlaspi caerulescens in natural populations from Northern Europe.

We examined recruitment, survival, life cycle and fecundity of two metallicolous (M, on metalliferous calamine soils) and two non-metallicolous (NM, on normal soils) populations of Thlaspi caerulescens in Belgium and Luxemburg. In each population, permanent plots were monitored over two reproductive seasons. In M populations, plots were located in two contrasting environments (grass versus grove) in order to test the influence of vegetation cover on life strategy.

An explicit test for the contribution of environmental maternal effects to rapid clinal differentiation in an invasive plant.

Population differentiation of alien invasive plants within their non-native range has received increasingly more attention. Common gardens are typically used to assess the levels of genotypic differentiation among populations.However, in such experiments, environmental maternal effects can influence phenotypic variation among individuals if seed sources are collected from field populations under variable environmental regimes.

Increased porcine circovirus type 2 replication in porcine leukocytes in vitro and in vivo by concanavalin A stimulation.

Previously, it was shown that modulation of the immune system enhances porcine circovirus type 2 (PCV2) replication in pigs. In the present study, the effect of the mitogen concanavalin A (ConA) on PCV2 replication was investigated. Since ConA induces T-lymphocyte activation and initiates the production of interferon-gamma (IFN-gamma), a cytokine that enhances PCV2 replication in porcine epithelial and monocytic cell lines in vitro, it was examined if the effects observed with ConA were mediated by IFN-gamma.

Impacts of alien invasive plants on soil nutrients are correlated with initial site conditions in NW Europe.

Alien invasive plants are capable of modifying ecosystem function. However, it is difficult to make generalisations because impacts often appear to be species- and site-specific. In this study, we examined the impacts of seven highly invasive plant species in NW Europe (Fallopia japonica, Heracleum mantegazzianum, Impatiens glandulifera, Prunus serotina, Rosa rugosa, Senecio inaequidens, Solidago gigantea) on nutrient pools in the topsoil and the standing biomass.

Cost of adaptation to a metalliferous environment for Thlaspi caerulescens: a field reciprocal transplantation approach.

Field reciprocal transplantations of two metallicolous populations (Mpops) and two nonmetallicolous populations (NMpops) of Thlaspi caerulescens were performed here to determine the pattern of local adaptation and to assess the cost of adaptation of Mpops to a metalliferous environment (Menv). The role of herbivores as an important selective pressure in the nonmetalliferous environment (NMenv) was also examined. Growth, survival, fitness, life cycle and herbivore consumption were monitored for each transplant for 2 yr.

Development of Issoria lathonia (Lepidoptera: Nymphalidae) on zinc-accumulating and nonaccumulating Viola species (Violaceae).

The larvae of Issoria lathonia L. feed in natural conditions on several Viola spp., among which are the zinc-accumulating Viola calaminaria (Gingins) Lej.

Do metal-rich plants deter herbivores? A field test of the defence hypothesis.

Some plant species growing on metalliferous soils are able to accumulate heavy metals in their shoots up to very high concentrations, but the selective advantage of this behaviour is still unknown. The most popular hypothesis, that metals protect plants against herbivores, has been tested several times in laboratory conditions, with contradictory results. We carried out the first large-scale test of the defence hypothesis in eight natural populations of the model Zn hyperaccumulator Thlaspi caerulescens J.

Reaction norms of life history traits in response to zinc in Thlaspi caerulescens from metalliferous and nonmetalliferous sites.

* We examined phenotypic plasticity of fitness components in response to zinc (Zn) in the Zn hyperaccumulator, Thlaspi caerulescens. * Two populations from Zn-enriched soils (M) and two populations from normal soils (NM) were grown in pots at three Zn concentrations (0, 1000 and 8000 mg kg(-1) Zn), for an entire life cycle. Growth, Zn accumulation and fitness components were assessed.

Porcine circovirus 2 uses heparan sulfate and chondroitin sulfate B glycosaminoglycans as receptors for its attachment to host cells.

Monocyte/macrophage lineage cells are target cells in vivo for porcine circovirus 2 (PCV2) replication. The porcine monocytic cell line 3D4/31 supports PCV2 replication in vitro, and attachment and internalization kinetics of PCV2 have been established in these cells. However, PCV2 receptors remain unknown.

Correlation between the presence of neutralizing antibodies against porcine circovirus 2 (PCV2) and protection against replication of the virus and development of PCV2-associated disease.

Background: In a previous study, it was demonstrated that high replication of Porcine circovirus 2 (PCV2) in a gnotobiotic pig was correlated with the absence of PCV2-neutralizing antibodies. The aim of the present study was to investigate if this correlation could also be found in SPF pigs in which PMWS was experimentally reproduced and in naturally PMWS-affected pigs.

Results: When looking at the total anti-PCV2 antibody titres, PMWS-affected and healthy animals seroconverted at the same time point, and titres in PMWS-affected animals were only slightly lower compared to those in healthy animals.

Enhancement of porcine circovirus 2 replication in porcine cell lines by IFN-gamma before and after treatment and by IFN-alpha after treatment.

Stimulation of the porcine immune system causes increased replication of porcine circovirus 2 (PCV2) in vivo. In the present study, we investigated whether various cytokines (interleukin-1 [IL-1], IL-6, IL-10, tumor necrosis factor-alpha [TNF-alpha], interferon-alpha [IFN-alpha], and IFN-gamma) are able to influence PCV2 infection in vitro. No changes were observed in IL-1, IL-6, TNF-alpha, or IL-10-treated cells.

Correlation between type of adaptive immune response against porcine circovirus type 2 and level of virus replication.

Porcine circovirus 2 (PCV2) replication is characterized by high variation among infected pigs. This study investigated the role of immunologic responses in causing this variation. Twelve gnotobiotic pigs were inoculated with PCV2.

Binding and entry characteristics of porcine circovirus 2 in cells of the porcine monocytic line 3D4/31.

Porcine circovirus 2 (PCV2) is associated with post-weaning multisystemic wasting syndrome and reproductive problems in pigs. Cells of the monocyte/macrophage lineage are important target cells in PCV2-infected pigs, but the method of binding and entry of PCV2 into these cells is unknown. Therefore, binding and entry of PCV2 to the porcine monocytic cell line 3D4/31 were studied by visualization of binding and internalization of PCV2 virus-like particles (VLPs) by confocal microscopy and chemical inhibition of endocytic pathways (clathrin- and caveolae-mediated endocytosis and macropinocytosis), followed by evaluation of the level of PCV2 infection.