Maintenance of serological memory by polyclonal activation of human memory B cells

Production of antibodies can last for a lifetime, through mechanisms that remain poorly understood. Here, we show that human memory B lymphocytes proliferate and differentiate into plasma cells in response to polyclonal stimuli, such as bystander T cell help and CpG DNA. Furthermore, plasma cells secreting antibodies to recall antigens are produced in vivo at levels proportional to the frequency of specific memory B cells, even several years after antigenic stimulation. Although antigen boosting leads to a transient increase in specific antibody levels, ongoing polyclonal activation of memory B cells offers a means to maintain serological memory for a human lifetime.     

Soil mineral nitrogen dynamics in fallow periods in a rainfed semiarid Mediterranean agricultural systems

Rainfed agricultural systems in semiarid Mediterranean environments are subject to erratic but often heavy rainfall events.As an agronomic practice,fallow periods can be included even within the existing European Union common policy for crop diversification.This study aimed to quantify the effects of previous mineral fertilization on soil mineral nitrogen (Nmin) content and potential nitrate leaching during no-till fallow periods of crop rotation.The Leaching Estimation and Chemistry Model (LEAC...     

Continuous infusion of propofol in dogs premedicated with methotrimeprazine

Objective To evaluate the cardiopulmonary and clinical effects of three different infusion rates of propofol in dogs premedicated with methotrimeprazine. Study design Randomized experimental trial. Animals Ten healthy adult mixed‐breed male and female dogs, weighing from 14 to 20 kg. Methods Dogs were premedicated with methotrimeprazine [1 mg kg^?1 intravenously (IV)] followed by induction of anesthesia with 4.5 mg kg^?1 of propofol IV and maintenance with propofol for 60 minutes as follows: T1, 0.2 mg kg^?1 minute^?1; T2, 0.3 mg kg^?1minute^?1; and T3, 0.4 mg kg^?1minute^?1. Heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP), end‐tidal CO₂ (P_ETCO₂), arterial hemoglobin O₂ saturation, arterial blood gases, and pedal and cutaneous reflexes were measured before and 5, 10, 20, 30, 45 and 60 minutes after the beginning of the propofol infusion. Statistical analysis was performed using an anova . Results Heart rate increased during anesthesia in all cases and arterial blood pressure decreased only in dogs in the T3 category. Respiratory depression was proportional to the infusion rate of propofol. Muscle relaxation was satisfactory, but analgesia was inadequate in the three treatments. Conclusions The infusion of 0.2–0.4 mg kg^?1 minute^?1 of propofol produced a dose‐dependent respiratory depression. The presence of a pedal withdrawal reflex and marked cardiovascular responses to this noxious stimulus suggests that anesthesia may not be of sufficient depth for surgery to be carried out. Clinical relevance Although several studies have been performed using propofol in animals, few studies have investigated the cardiopulmonary and analgesic effects with different doses. The determination of an adequate propofol infusion rate is necessary for the routine use of this intravenous anesthetic for the maintenance of anesthesia during major surgical procedures in dogs.     

In Vitro Evaluation of Antioxidant Potential of the Invasive Seagrass Halophila stipulacea

Marine organisms with fast growth rates and great biological adaptive capacity might have biotechnological interests, since ecological competitiveness might rely on enhanced physiological or biochemical processes’ capability promoting protection, defense, or repair intracellular damages. The invasive seagrass Halophila stipulacea, a non-indigenous species widespread in the Mediterranean Sea, belongs to this category. This is the premise to investigate the biotechnological interest of this species. In this study, we investigated the antioxidant activity in vitro, both in scavenging reactive oxygen species and in repairing damages from oxidative stress on the fibroblast human cell line WI-38. Together with the biochemical analysis, the antioxidant activity was characterized by the study of the expression of oxidative stress gene in WI-38 cells in presence or absence of the H. stipulacea extract. Concomitantly, the pigment pool of the extracts, as well as their macromolecular composition was characterized. This study was done separately on mature and young leaves. Results indicated that mature leaves exerted a great activity in scavenging reactive oxygen species and repairing damages from oxidative stress in the WI-38 cell line. This activity was paralleled to an enhanced carotenoids content in the mature leaf extracts and a higher carbohydrate contribution to organic matter. Our results suggest a potential of the old leaves of H. stipulacea as oxidative stress damage protecting or repair agents in fibroblast cell lines. This study paves the way to transmute the invasive H. stipulacea environmental threat in goods for human health.     

The high tolerance of different pomegranate cultivars to the excess of boron in irrigation water is due to their capacity to limit boron transport from the root to the leaves

Background : Presently, irrigation waters often have a high concentration of boron (B), and the fruit trees in the Mediterranean areas, in general, are exposed to a high risk of B toxicity. Aims : To test the hypothesis that pomegranate trees are very tolerant to the presence of B in the irrigation water, to elucidate the physiological mechanisms behind this tolerance, and to assess differences between different varieties. Methods : In this study, the physiological and nutritional behavior of three pomegranate cultivars (‘Mollar de Elche', ‘Valenciana', and ‘Wonderful'), treated with five B concentrations (0.25, 1.25, 2.5, 5.0, 10.0 mg L^?1), were studied. At day 30 and 60 after the start of the treatments, growth measurements, gas exchange parameters and organic solutes were recorded. Results : Almost no significant differences were observed between the B treatments for any of the cultivars. Increasing the B concentration in the nutrient solution increased B concentrations in the leaves, but they never exceed 40 mg kg^?1 of B. In the roots, however, B concentrations were very high, up to 400 mg kg^?1. Conclusion : Pomegranate trees are very tolerant to B excess due to their ability to accumulate B in great quantities in the root, without causing toxicity to this part of the plant, thus limiting its transport to the shoots.     

EFFECT OF ROOTSTOCK ON SALT TOLERANCE OF LOQUAT: GROWTH AND MINERAL COMPOSITION

The salinity tolerance of loquat grafted onto anger or onto loquat was studied. The plants were irrigated using solutions containing 5, 25, 35, 50, or 70 mM sodium chloride (NaCl) for five months. Different parameters of vegetative growth were studied, all of them showing that plants grafted onto loquat are much less salinity-tolerant than those grafted onto anger. Thus, the concentration of NaCl that produced a growth reduction of 50% (C₅₀) for the growth parameters of the shoot was around 35 mM for loquat plants grafted onto loquat. With the NaCl levels employed, loquat-anger plants did not reach the C₅₀. Lower chloride (Cl^?) and sodium (Na⁺) uptake, higher potassium (K⁺)-Na⁺ selectivity and a lower reduction in the leaf magnesium (Mg²⁺) concentration for the loquat-anger combination can explain the higher salinity tolerance compared to loquat-loquat.     

Responses of elephantgrass to nutrient solution ph levels

Seedlings of elephantgrass (Pennisetumpurpureum, Schum.), cvs. Vruckwona and Napier, were grown in aerated nutrient solution and exposed to pH levels of 4.0, 5.0, 6.0, or 7.0. After 30 days under controlled conditions, the effects on growth were evaluated. Plants exposed to pH 5.0, as compared to those under pH 4.0, showed increases in total leaf area, plant height, number of leaves (NL), and leaf, root, and stem fresh weight. No significant differences were found in stubble fresh weight, maximum individual leaf area, leaf area ratio (LAR), leaf area:plant height ratio, and leaf, root, stem, and stubble dry weight and dry matter percentage. Seedlings exposed to pH 4.0, as compared to those under pH 5.0, exhibited higher leaf:stem ratio on a fresh weight basis (FWR) and a tendency for higher leaf :stem ratio on a dry matter basis (DWR). Cultivar Vruckwona yielded superior results than Napier for most studied parameters, except for NL, LAR, and DWR (in which there were no significant differences) and for stubble length and FWR (in which Napier performed better). The results suggest that reductions below 5.0 in the nutrient solution pH cause growth inhibition, affecting root, stem, and leaf FW to a greater extent. The magnitude of such effects varies among contrasting cultivars. In turn, pH increases above 5.0 induce no significant growth reduction or promotion.     

Using fuzzy clustering algorithms to describe the distribution of trace elements in arable calcareous soils in northwest Iran

Accumulation of trace elements in arable soils is an important global hazard worldwide. In this research, the available content of Zn, Fe, B, Co, Cu, Mn, Mo and other soil parameters (pH, organic carbon content, carbonates and electrical conductivity) were analysed in northwest Iran. Concentration levels of trace elements were relatively low in areas with high pH values and low organic matter content, and only the Mo value exceeded the reference threshold. Based on the correlation among the elements, two datasets were produced. The first consists of Fe and Mn data, while the second contains Zn, B, Co, Cu and Mo data. Two fuzzy clustering approaches, Fuzzy C-means (FCM) and Gustafson–Kessel (GK), were applied for clustering both datasets. Multiple accumulation of trace elements was investigated from the clustering results and then visualized in spatial regionalization maps. The fuzzy clustering evaluating indices showed that the GK method was more appropriate than FCM for clustering datasets. The results revealed that the first and second datasets were divided into seven and six clusters, respectively. Fuzzy clustering analyses combined with geostatistical methods were used to map the spatial variability of each cluster. This method enabled the monitoring of multiple metal accumulation in large agricultural soils.     

Olive mill wastewater spreading and AMF inoculation effects in a low-input semi-arid Mediterranean crop succession

ABSTRACT

The study aimed to evaluate, in a marginal semi-arid Mediterranean agro-ecosystem (Sicily-Italy), the effects of arbuscular mycorrhizal fungi (AMF) inoculation and raw olive mill wastewater (OMW) (40 and 80 m³ ha^?1) on forage (durum wheat-snail medick intercropping) yield, and grain production of broad bean and chickpea. AMF inoculation significantly increased (+13.6%) forage dry biomass and durum wheat nitrogen (+22.8%) and phosphorus (+32.5%) uptake. AMF inoculation, significantly promoted broad bean phosphorus uptake (+11.5%) and root nodule number (+13.9%) in the absence of OMW. OMW spreading reduced weeds in the forage (?31.3%), root nodule number (?29.7%) and dry weight (?22.7%) in broad bean. OMW also significantly increased snail medick dry biomass (+19.3%) as compared to control treatments (0, 40 and 80 m³ H₂O ha^?1, average production 361 g m^?2), and broad bean grain yield with a production of 2.46 ± 0.12 and 1.94 ± 0.09 Mg ha^?1 with and without OMW, respectively. During the experiment AMF colonization was not affected by OMW volumes. The results obtained showed that in a marginal Mediterranean agro-ecosystem: 1) OMW, notwithstanding spreading volumes, is a valuable amendment to maximize legume yield while 2) AMF inoculation is a valuable practice to improve biomass production and N and P uptake in wheat.