Exclusion of livestock grazing and wood collection in dryland savannah: an effect on long‐term vegetation succession

Sahelian savannah faces increasing pressure from human activities, leading to its degradation. The aim of this study was to investigate the possibility of restoration of dryland savannah vegetation by the elimination of disturbance factors on the ecosystem. Is degraded dryland savannah vegetation able to be restored by means of natural succession? What is the timescale for its recovery? The study took place in the Bandia Reserve, 65 km south‐east of Dakar (Senegal), a unique site with two successional stages due to the elimination of uncontrolled exploitation. The vegetation structure of 15 years (15YRS) and 5 years (5YRS) after fencing was compared with vegetation exposed to continuous livestock grazing and wood collection outside the fenced area. Calculated by redundancy analysis, a significant effect of selected areas on the cover of all species was revealed and successional stage explained more than 45% of data variability. Perennial forbs, annual forbs and perennial grasses achieved the highest cover in 5YRS, woody species in 15YRS and annual grasses in the area outside of the fenced reserve. The dominant woody species Acacia seyal, A. ataxacantha, A. nilotica subsp. adstringens and Balanites aegyptiaca reconstituted the dense formation of Acacia bushland by means of natural succession in the 15YRS area.     

The negative effect of magnetic nanoparticles with ascorbic acid on peritoneal macrophages

Neurochemical Research - Superparamagnetic iron oxide nanoparticles (SPIOn) are widely used as a contrast agent for cell labeling. Macrophages are the first line of defense of organisms in contact...     

Chinko/Mbari drainage basin represents a conservation hotspot for Eastern Derby eland in Central Africa

One of the largest of antelopes, Derby eland (Taurotragus derbianus), is an important ecosystem component of African savannah. While the western subspecies is Critically Endangered, the eastern subspecies is classified as least concern. Our study presents the first investigation of population dynamics of the Derby eland in the Chinko/Mbari Drainage Basin, Central African Republic, and assesses the conservation role of this population. We analysed data from 63 camera traps installed in 2012. The number of individuals captured within a single camera event ranged from one to 41. Herds were mostly mixed by age and sex, mean group size was 5.61, larger during the dry season. Adult (AD) males constituted only 20% of solitary individuals. The overall sex ratio (M:F) was 1:1.33, while the AD sex ratio shifted to 1:1.52, reflecting selective hunting pressure. Mean density ranged from 0.04 to 0.16 individuals/km², giving an estimated population size of 445–1,760 individuals. Chinko harbours one of the largest documented populations of Derby eland in Central Africa, making Chinko one of its potential conservation hotspots.     

Effects of Sewage Sludge Application on Biomass Production and Concentrations of Cd,Pb and Zn in Shoots of <Emphasis Type="Italic">Salix</Emphasis> and <Emphasis Type="Italic">Populus</Emphasis> Clones: Improvement of Phytoremediation Efficiency in Contaminated Soils

Fast-growing clones of Salix and Populus species have been studied for phytoremediation of soils contaminated by risk elements (REs) using short-rotation coppice plantations. Biomass yield, accumulation and removal of RE (Cd, Pb and Zn) by highly productive willow (S1—(Salix schwerinii × Salix viminalis) × S. viminalis, S2—Salix × smithiana) and poplar (P1—Populus maximowiczii × Populus nigra, P2—P. nigra) clones were investigated with and without sewage sludge (SS) application. The precise field experiment was established in April 2008 on moderately Cd-, Pb- and Zn-contaminated soil. Initially, shoots were harvested after four seasons in February 2012 and then after two more seasons in February 2014. The application of SS limited plant growth during the first years of the experiment in the majority of treatments, mainly due to weed competition and higher concentrations of available soil nutrients causing lower yields than those of control (C) treatments. Well-developed roots were able to take advantage of SS applications, and shoot yield was mainly higher in SS treatments in the second harvest, reaching up to 15 t dry matter (DM)?ha^?1. Willows performed better than poplars. Application of SS reduced RE shoot concentrations compared to the C treatment. The removal of RE was significantly higher in the second harvest for all clones and elements (except the P2 clone), and the biomass yield was the major driving force for the amount of RE removed by shoots. Well-developed plantations of fast-growing trees showed better suitability for the phytoextraction of moderately contaminated soils for Cd and partly for Zn but not for Pb, which was less available to plants. From the four tested clones, S2 showed the best removal of Cd (up to 0.94 %) and Zn (up to 0.34 %) of the total soil element content, respectively, and this clone is a good candidate for phytoextraction. SS can be a suitable source of nutrients for Salix clones without any threat to the food chain in terms of biomass contamination, but its application to the soil can result in an increased incidence of some weeds during the first years of plantation.     

The human leucocyte antigen CD48 (MEM-102) is closely related to the activation marker Blast-1

The glycosyl phosphatidylinositol (GPI)-linked antigen recognized by monoclonal antibody (mAb) MEM-102 is expressed on all peripheral blood lymphocytes, both resting and activated. Its properties are very similar to a previously described activation antigen, Blast-1. The amino acid sequence deduced from the structure of cloned cDNA is identical to that of the Blast-1 antigen except for a single amino acid residue. There are several other minor differences in the nucleotide sequence of the Blast-1 and MEM-102 cDNAs that do not affect the predicted structure of the polypeptide product. The amino acid sequence of the first 15 N-terminal residues of the antigen purified from Raji cells is found in the deduced sequence close to the presumed boundary between the leader peptide and mature polypeptide. Properties of the recombinant product expressed in COS cells are similar to the antigen isolated from peripheral blood mononuclear cells (PBMNCs) or B-and T-cells lines. The antigen purified on immobilized mAb MEM-102 is recognized by all six known CD48 mAbs under western blotting conditions. COS cells transfected with MEM-102 cDNA react with all the CD48 mAbs. It is concluded that mAb MEM-102 is directed against the as yet poorly characterized antigen CD48, which is therefore structurally closely related to Blast-1. Several possibilities are discussed that might account for the apparent discrepancy between the broad pan-leucocyte expression of the MEM-102/CD48 antigen and much more restricted expression of the epitope recognized by the previously described mAb defining the Blast-1 antigen.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number M 37766.     

Combination of two chromophores: synthesis and PDT application of porphyrin-pentamethinium conjugate

A general method for the synthesis of a novel porphyrin with pentamethine periphery substitution is described. The combination of two chromophoric systems, a porphyrin macrocycle and a polymethine moiety was achieved by transformation of tetrapyridyl porphyrin. The synthetic strategy included conversion of the tetrapyridyl porphyrin to its corresponding 2,4-dinitrophenylpyridinuim salt, which was subsequently converted to tetrakis(meso-pentamethinium salt) on the porphyrin core. This novel porphyrin exhibited PDT properties as manifested by the induction of apoptosis in the myeloid cell line HL-60 and the effective reduction of amelanotic melanoma in nude mice.     

The effects of reactive nitrogen and oxygen species on the regeneration and growth of cucumber cells from isolated protoplasts

The present study investigated changes in the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in isolated mesophyll protoplasts and cell cultures of the cucumber Cucumis sativus cv. Marketer. Although only a minor increase in the level of nitrogen oxide (NO) was observed during the first 7 days of culture following protoplast isolation, a substantial accumulation of ROS was detected. Compounds known to modulate endogenous ROS and RNS levels were employed to study their role in cucumber protoplast regeneration and growth. Supplementing the culture medium with the NO donors S-nitrosoglutathione and sodium nitroprusside and the ROS scavenger ascorbate significantly increased protoplast viability and cell density. In contrast, cell density was significantly decreased following the addition of catalase to the medium. Scavenging of ROS and RNS induced the formation of cucumber microcalli, thus suggesting a differential role of NO in the maintenance of cell viability and in the control of cell division. Our findings confirm the crucial role of controlled ROS and RNS production in both protoplast regeneration and cellular growth and differentiation.     

End products of lipid peroxidation in erythrocyte membranes in Alzheimer's disease

Alzheimer's disease (AD) is accompanied by oxidative stress in the brain. Because the brain tissue is rich in polyunsaturated fatty acids, it is prone to the free radical attack resulting in lipid peroxidation. Intermediates of lipid peroxidation may diffuse from the primary site, cross the blood-brain barrier and modify erythrocyte membranes in the bloodstream. We exposed isolated erythrocyte membranes from patients with AD and the control group to in vitro free radical damage and monitored the accumulation of the end products of lipid peroxidation, lipofuscin-like pigments (LFPs), by fluorescence spectroscopy. LFPs were analyzed by means of tridimensional and synchronous fluorescence spectroscopy. The levels of LFP formed during in vitro peroxidation were significantly higher in erythrocyte membranes from patients with AD compared with the control group. Furthermore, the chemical composition of LFP in AD was different from the control group. The analysis of the specific modifications of erythrocyte membranes in AD is of great medical importance regarding the need of a diagnostic blood biomarker.