Human Plasmacytoid Dendritic Cells Elicited Different Responses after Infection with Pathogenic and Nonpathogenic Junin Virus Strains

The arenavirus Junin virus (JUNV) is the etiologic agent of Argentine hemorrhagic fever. We characterized the JUNV infection of human peripheral blood-derived plasmacytoid dendritic cells (hpDC), demonstrating that hpDC are susceptible to infection with the C#1 strain (attenuated) and even more susceptible to infection with the P (virulent) JUNV strain. However, hpDC elicited different responses in terms of viability, activation, maturation, and cytokine expression after infection with both JUNV strains.     

Flood pulses drive the temporal dynamics of assemblages of aquatic insects (Heteroptera and Coleoptera) in a temperate floodplain

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Estimating crop N uptake from organic residues using a new approach to the 15N isotope dilution technique

Experiments were conducted to test a new approach to the ¹⁵N isotope dilution technique for estimating crop N uptake from organic inputs. Soils were pre-labelled with ¹⁵N fertiliser and a carbon source. These were then incubated until there was stabilisation of the ¹⁵N abundance of the inorganic N pool and resumption of inorganic N concentrations. Residues were then applied to the soils and planted with ryegrass (Lolium perenneL.) to determine the nitrogen derived from the residue (Ndfr) using the isotope dilution equations. This method was compared with the direct method, i.e. where ¹⁵N-labelled residues were added to the soil and Ndfr in the ryegrass calculated directly. Estimates of percentage nitrogen derived from the residue (%Ndfr) alfalfa (Medicago sativaL.) in the ryegrass, were similar, 22 and 23% for the direct and soil pre-labelling methods, respectively, in the Wechsel sandy loam. Also, estimates of the %Ndfr from soybean (Glycine max (L.) Merr) residues in the Krumbach sandy loam were similar 34% (direct) and 36% (soil pre-labelling approach). However, in the Seibersdorf clay loam, the %Ndfr from soybean was 49% using the direct method and 61% using the soil pre-labelling method; yet Ndfr from common bean residue was 46% using the direct approach and 40% using the pre-labelling, not significantly different (P > 0.05). The soil pre-labelling approach appears to give realistic values for Ndfr. It was not possible to obtain an estimate of Ndfr using the soil pre-labelling method from the maize residues (Zea mays L.) in two of the soils, as there was no increase in the total N of the ryegrass over the growing period. This was probably due to microbial immobilisation of inorganic N, as a result of the wide C:N ratio of the residue added. The results suggest that the new soil pre-labelling method is feasible and that it is a potentially useful technique for measuring N release from a wide range or organic residues, but it requires further field-testing. This revised version was published online in June 2006 with corrections to the Cover Date.     

Seasonal dynamics of mosquitoes (Diptera: Culicidae) in Osijek (Croatia) for the period 1995–2004

The ten year research (1995–2004) of adult mosquitoes in the area of Osijek by dry ice baited CDC traps has provided significant information on mosquito species, species prevalence, their dynamics and seasonal activity. A total of 207,136 adult mosquitoes comprising twenty species belonging to the following genera: Anopheles, Ochlerotatus, Aedes, Culex, Coquillettidia, Culiseta and Uranotaenia were collected. The seven most common species collected during this study were: Aedes vexans (75.6%), Ochlerotatus sticticus (13.3%), Culex pipiens complex (5.9%), Anopheles maculipennis complex (1.9%), Oc. cantans (0.9%), Oc. caspius (0.6%) and Oc. excrucians (0.6%). The temporal changes in the relative abundance of the twenty mosquito species in the Osijek area were reflected in three peaks: in May, July and September. Seasonal population dynamics differed between years and between mosquito species in relation to wetland, urban and forest habitats and was influenced by water level of the Drava and the Danube rivers.     

Protoplast fusion between a petite strain ofCandida utilis andSaccharomyces cerevisiae respiratory-competent cells

Prototrophic RD mutant cells ofCandida utilis NRRL-Y-1084 and auxotrophic mutant respiratory-competent cells ofSaccharomyces cerevisiae 4003-5Ba his ₄ leu ₂ can ^S meth ₂ trp ₅ ade ₁ ura ₃ gal were turned into protoplasts to be further fused with the aid of polyethylene glycol (PEG) and Ca²⁺ ions. Minimal medium containing glycerol as the carbon source was employed for fusion product selection. The respiratory-competent fusion products, mainly oval cells, resembledCandida utilis and had the fermentative abilities of this strain (dextrose, sucrose, raffinose). Five fusion products were analyzed as to their ability to metabolize dextrose, xylose, cellobiose, trehalose, glycerol, succinic acid, citric acid, salycin, and maltose. Fusion products partially restored the respiratory-competentCandida utilis capacity to grow by use of these carbon compounds, and none of theSaccharomyces cerevisiae fermenting abilities were found. Our results would suggest either a partial recombination between parental mitochondria or some occurring phenomenon affecting the cell, membrane function after somatic fusion without concomitant nuclear fusion.     

Histological and histochemical study of the duodenum of the plains viscacha (Lagostomus maximus) at different stages of its ontogenetic development

The general objective of this study focused on the duodenal histological and histochemical analysis of fetuses and adults of plains viscacha (Lagostomus maximus) from the Buenos Aires province (Argentina). Histological techniques, histochemical procedures for localizing and characterizing glycoproteins (GPs) and lectin histochemical techniques for the identification of specific sugar residues were used. The duodenal structure of all age groups here considered was typical of mammals. We identified a proliferation phase and an epithelial morphogenesis in mid‐gestational fetuses, an intermediate period of cell differentiation in at‐term fetuses and a posterior stage of physiological maturation in adults. According to histochemistry, the diverse GPs elaborated and secreted into the duodenum show a high degree of histochemical complexity related to the multiple functions of mucus in the digestive tract. The GPs in the duodenum of L. maximus and their glycosylation patterns varied according to the animal's age and the developmental state of the organ.     

The Effects of Cadmium-Zinc Interactions on Biochemical Responses in Tobacco Seedlings and Adult Plants

The objective of the present study was to investigate the effects of cadmium-zinc (Cd-Zn) interactions on their uptake, oxidative damage of cell macromolecules (lipids, proteins, DNA) and activities of antioxidative enzymes in tobacco seedlings as well as roots and leaves of adult plants. Seedlings and plants were exposed to Cd (10 µM and 15 µM) and Zn (25 µM and 50 µM) as well as their combinations (10 µM or 15 µM Cd with either 25 µM or 50 µM Zn). Measurement of metal accumulation exhibited that Zn had mostly positive effect on Cd uptake in roots and seedlings, while Cd had antagonistic effect on Zn uptake in leaves and roots. According to examined oxidative stress parameters, in seedlings and roots individual Cd treatments induced oxidative damage, which was less prominent in combined treatments, indicating that the presence of Zn alleviates oxidative stress. However, DNA damage found in seedlings, and lower glutathione reductase (GR) and superoxide dismutase (SOD) activity recorded in both seedlings and roots, after individual Zn treatments, indicate that Zn accumulation could impose toxic effects. In leaves, oxidative stress was found after exposure to Cd either alone or in combination with Zn, thus implying that in this tissue Zn did not have alleviating effects. In conclusion, results obtained in different tobacco tissues suggest tissue-dependent Cd-Zn interactions, which resulted in activation of different mechanisms involved in the protection against metal stress.     

Efficacy of mosquito attractants in various habitats of a floodplain

Efficacy of different mosquito attractants was invesigated at four sites in three plant communities (Galio-Salicetum albae, Populetum nigro-albae, Genisto elatae-Quercetum roboris) of flooded and forest habitats in Kopački rit Nature Park, Croatia. The attractants were: dry ice, horse urine, horse urine + acetone, acetone, 1-octen-3-ol and ammonium hydroxide baited CDC traps. A total of 11,441 mosquito specimens of 12 species were collected. Aedes vexans (91.43%) was the most numerous species. A statistically significant difference between the efficacy of dry ice and the other attractants was shown, whereas there was no difference between the other attractants. A greater number of specimens and species number were noted in the flooded plant communities (Populetum nigro-albae). The response of Ae. vexans to dry ice was higher in flooded sites, and it was significantly lower in forest habitat (Genisto elatae-Quercetum roboris) according to fuzzy c-means cluster analysis. The same analysis shows a higher efficacy of other attractants (horse urine, horse urine + acetone, acetone, octenol and ammonium hydroxide) in forest habitat when compared to the flooded area habitats.