Rossby wave propagation tracks in southern hemisphere mean basic flows associated to generalized frosts over southern South America

Based on previous observational studies on cold extreme events over southern South America, some recent studies suggest a possible relationship between Rossby wave propagation remotely triggered and the occurrence of frost. Using the concept of linear theory of Rossby wave propagation, this paper analyzes the propagation of such waves in two different basic states that correspond to austral winters with maximum and minimum generalized frost frequency of occurrence in the Wet Pampa (central-northwest Argentina). In order to determine the wave trajectories, the ray tracing technique is used in this study. Some theoretical discussion about this technique is also presented. The analysis of the basic state, from a theoretical point of view and based on the calculation of ray tracings, corroborates that remotely excited Rossby waves is the mechanism that favors the maximum occurrence of generalized frosts. The basic state in which the waves propagate is what conditions the places where they are excited. The Rossby waves are excited in determined places of the atmosphere, propagating towards South America along the jet streams that act as wave guides, favoring the generation of generalized frosts. In summary, this paper presents an overview of the ray tracing technique and how it can be used to investigate an important synoptic event, such as frost in a specific region, and its relationship with the propagation of large scale planetary waves.

Basic aminopeptidase activity is an emerging biomarker in collagen-induced rheumatoid arthritis

The objective of this study was to investigate the catalytic activity of basic aminopeptidase (APB) and its association with periarticular edema and circulating tumor necrosis factor (TNF)-alpha and type II collagen (CII) antibodies (AACII) in a rat model of rheumatoid arthritis (RA) induced by CII (CIA). Edema does not occur in part of CH-treated, even when AACII is higher than in control. TNF-alpha is detectable only in edematous CII-treated. APB in synovial membrane is predominantly a membrane-bound activity also present in soluble form and with higher activity in edematous than in non-edematous CH-treated or control. Synovial fluid and blood plasma have lower APB in non-edematous than in edematous CII-treated or control. In peripheral blood mononuclear cells (PBMCs) the highest levels of APB are found in soluble form in control and in membrane-bound form in non-edematous CII-treated. CII treatment distinguishes two categories of rats: one with arthritic edema, high AACII, detectable TNF-alpha, high soluble and membrane-bound APB in synovial membrane and low APB in the soluble fraction of PBMCs, and another without edema and with high AACII, undetectable TNF-alpha, low APB in the synovial fluid and blood plasma and high APB in the membrane-bound fraction of PBMCs. Data suggest that APB and CIA are strongly related. (C) 2011 Elsevier B.V. All rights reserved.

Crotoxin alters lymphocyte distribution in rats: Involvement of adhesion molecules and lipoxygenase-derived mediators

Crotoxin is the main neurotoxic component of Crotalus durissus terrificus snake venom and modulates immune and inflammatory responses, interfering with the activity of leukocytes. In the present work, the effects of crotoxin on the number of blood and lymphatic leukocytes and on lymph nodes and spleen lymphocytes population were investigated. The toxin s.c. administered to male Wistar rats, decreases the number of lymphocytes in blood and lymph circulation and increases the content of B and T-lymphocytes in lymph nodes. These effects were detected 1-2 h after treatment. The crotoxin molecule is composed of two subunits, an acidic non-toxic polypeptide, named crotapotin and a toxic basic phospholipase A(2) (PLA(2)). PLA(2), but not crotapotin, decreased the number of circulating blood and lymph lymphocytes. Crotoxin promotes leukocyte adherence to endothelial cells of blood microcirculation and to lymph node high endothelial venules, which might contribute to the drop in the number of circulating lymphocytes. Crotoxin increases expression of the adhesion molecule LFA-1 in lymphocytes. The changes in the expression of the adhesion molecule might contribute, at least in part, for the increased leukocyte adhesion to endothelium. Zileuton, a 5-lipoxygenase inhibitor, blocked the decrease in the number of circulating leukocytes induced by crotoxin and also abolished the changes observed in leukocyte-endothelial interactions, suggesting the involvement of lipoxygenase-derived mediators in the effects of the toxin. (c) 2008 Elsevier Ltd. All rights reserved.

SBTX, a new toxic protein distinct from soyatoxin and other toxic soybean [Glycine max] proteins, and its inhibitory effect on Cercospora sojina growth

SBTX, a novel toxin from soybean, was purified by ammonium sulfate fractionation followed by chromatographic steps DEAE-Cellulose, CM-Sepharose and Superdex 200 HR fast-protein liquid chromatography (FPLC). Lethality of SBTX to mice (LD50 5.6 mg/kg) was used as parameter in the purification steps. SBTX is a 44-kDa basic glycoprotein composed of two polypeptide chains (27 and 17 kDa) linked by a disulfide bond. The N-terminal sequences of the 44 and 27 kDa chains were identical (ADPTFGFTPLGLSEKANLQIMKAYD), differing from that of 17 kDa (PNPKVFFDMTIGGQSAGRIVMEEYA). SBTX contains high levels of Glx, Ala, Asx, Gly and Lys and showed maximum absorption at 280 nm, epsilon(1 cm) (1%) of 6.3, and fluorescence emission in the 290-450nm range upon excitation at 280nm. The secondary structure content was 35% alpha-helix, 13% beta-strand and beta-sheet, 27% beta-turn, 25% unordered, and 1% aromatic residues. Immunological assays showed that SBTX was related to other toxic proteins, such as soyatoxin and canatoxin, and cross-reacted weekly with soybean trypsin inhibitor and agglutinin, but it was devoid of protease-inhibitory and hemagglutinating activities. The inhibitory effect of SBTX on growth of Cercospora sojina, fungus causing frogeye leaf spot in soybeans, was observed at 50 mu g/ml, concentration 112 times lesser than that found to be lethal to mice. This effect on phytopathogenic fungus is a potential attribute for the development of transgenic plants with enhanced resistance to pathogens. (c) 2007 Elsevier Ltd. All rights reserved.

Basic oxygen furnace slag as a treatment material for pathogens: Contribution of inactivation and attachment in virus attenuation

Basic oxygen furnace (BOF) slag media were studied as a potential treatment material in on-site sanitation systems. Batch and column studies were conducted to evaluate attenuation of the bacteriophage PR772 and 0.190 mu m diameter microspheres by BOF media, and to delineate the relative contributions of two principle processes of virus attenuation: inactivation and attachment. In the batch studies, conducted at 4 degrees C, substantial inactivation of PR772 did not occur in the pH 7.6 and 9.5 suspensions. At pH 11.4, bimodal inactivation of PR772 was observed, at an initial rate of 2.1 log C/C(0) day(-1) for the first two days, followed by a much slower rate of 0.124 log C/C(0) day(-1) over the following 10 days. Two column studies were conducted at 4 degrees C at a flow rate of 1 pore volume day(-1) using two slag sources (Stelco, Ontario; Tubarao, Brazil) combined with sand and pea gravel. In both column experiments, the effluent microsphere concentration approached input concentrations over time (reductions of 0.1-0.2 log C/C(0)), suggesting attachment processes for microspheres were negligible. Removal of PR772 virus was more pronounced both during the early stages of the experiments, but also after longer transport times (0.5-1.0 log C/C(0)). PR772 reduction appeared to be primarily as a result of virus inactivation in response to the elevated pH conditions generated by the BOF mixture (10.6-11.4). On-site sanitation systems using BOF media should be designed to maintain sufficient contact time between the BOF media and the wastewater to allow sufficient residence time of pathogens at elevated pH conditions. (C) 2009 Published by Elsevier Ltd.