Variation in antioxidant properties and phenolics concentration in different organs of wild growing and greenhouse cultivated Castilleja tenuiflora Benth.

The content of total phenolic compounds and flavonoids was determined in methanol extracts of root, stem, leaves, and inflorescences from wild growing and greenhouse cultivated plants of Castilleja tenuiflora. The antioxidant activity in each extract was evaluated using three in vitro models: scavenging of free radicals with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), and reducing power by the phosphomolybdenum assay. Both, antioxidant activity and phytochemicals content were influenced significantly (P < 0.05) by the source of the plant material and the organ. Cultivated plants had the highest content of phenolic compounds (37.95 mg gallic acid equiv. g^?1 dry weight, P < 0.05) and the strongest antioxidant activity. Total phenolic compounds content correlated significantly with the antioxidant activity for all studied plant material and organs (P < 0.05). TLC profile using DPPH as a detection reagent indicated that the phenylethanoids verbascoside and isoverbascoside are the main contributors to the free-radical scavenging of C. tenuiflora. Cultivated plants of C. tenuiflora are an alternative source of natural antioxidants to wild growing plants. The antioxidant properties of C. tenuiflora may be associated with its traditional use to treat conditions consistent with radical-related diseases (e.g. inflammation, tumors).     

Discovery of a Protective Rickettsia prowazekii Antigen Recognized by CD8+ T Cells,RP884, Using an In Vivo Screening Platform

Rickettsia prowazekii has been tested for biological warfare due to the high mortality that it produces after aerosol transmission of very low numbers of rickettsiae. Epidemic typhus, the infection caused by these obligately intracellular bacteria, continues to be a threat because it is difficult to diagnose due to initial non-specific symptoms and the lack of commercial diagnostic tests that are sensitive and specific during the initial clinical presentation. A vaccine to prevent epidemic typhus would constitute an effective deterrent to the weaponization of R. prowazekii; however, an effective and safe vaccine is not currently available. Due to the cytoplasmic niche of Rickettsia, CD8⁺ T-cells are critical effectors of immunity; however, the identification of antigens recognized by these cells has not been systematically addressed. To help close this gap, we designed an antigen discovery strategy that uses cell-based vaccination with antigen presenting cells expressing microbe''s proteins targeted to the MHC class I presentation pathway. We report the use of this method to discover a protective T-cell rickettsial antigen, RP884, among a test subset of rickettsial proteins.     

Polyparasitism and its impact on the immune system

Parasitic infections are common in many tropical and sub-tropical regions of the world and concomitant infection, polyparasitism, is the rule rather than the exception in such areas. At the immunological level, different parasites induce quite different responses characterised, for example, by protozoa that polarise responses towards Th1, whilst helminths are strong Th2 and regulatory T cell inducers. The question of how the co-existence of such parasites within the same host might influence the immunological responses to each species and, more importantly, whether such interactions affect resistance, susceptibility or clinical outcome, needs to be addressed in well-designed studies of sufficient power. The current paper discusses what we know as well as the gaps in our knowledge of polyparasitism.     

Simple stochastic fingerprints towards mathematical modeling in biology and medicine. 3. ocular irritability classification model

MARCH-INSIDE methodology and a statistical classification method—linear discriminant analysis (LDA)—is proposed as an alternative method to the Draize eye irritation test. This methodology has been successfully applied to a set of 46 neutral organic chemicals, which have been defined as ocular irritant or nonirritant. The model allow to categorize correctly 37 out of 46 compounds, showing an accuracy of 80.46%. Specifically, this model demonstrates the existence of a good categorization average of 91.67 and 76.47% for irritant and nonirritant compounds, respectively. Validation of the model was carried out using two cross-validation tools: Leave-one-out (LOO) and leave-group-out (LGO), showing a global predictability of the model of 71.7 and 70%, respectively. The average of coincidence of the predictions between leave-one-out/leave-group-out studies and train set were 91.3% (42 out of 46 cases)/89.1% (41 out of 46 cases) proving the robustness of the model obtained. Ocular irritancy distribution diagram is carried out in order to determine the intervals of the property where the probability of finding an irritant compound is maximal relating to the choice of find a false nonirritant one. It seems that, until today, the present model may be the first predictive linear discriminant equation able to discriminate between eye irritant and nonirritant chemicals.     

Cryopreservation of <Emphasis Type="Italic">Pinus radiata</Emphasis> embryogenic tissue: effects of cryoprotective pretreatments on maturation ability

The goal of the study was to quantify the effect of different cryoprotective pretreatments on the maturation ability of cryopreserved Pinus radiata embryogenic tissue. Fourteen cell lines were evaluated under five pretreatments: (1) Dimethyl sulfoxide 5% (v/v); (2) Dimethyl sulfoxide 10% (v/v); (3) Dimethyl sulfoxide 5% (v/v) and 0.09 M of l-proline; (4) Dimethyl sulfoxide 10% (v/v) and 0.09 M of l-proline; (5) 0.09 M of l-proline and compared to embryogenic tissue that was not cryopreserved (control). The cell lines were thawed at 37 °C to evaluate the recovery percentage and determine the maturation ability. The recovery rate of all cryopreserved material was significantly lower than the control and material treated with 0.09 M of l-proline, in absent dimethyl sulfoxide, showed the lowest levels of recovery. Regarding the number of embryos, an interaction between pretreatments and the cell lines under evaluation was identified. Moreover, morphological differences in the plants being treated with the most concentrated Dimethyl sulfoxide pretreatment was observed. At the microscopic level, no damage or morphological changes in proembryogenic masses were observed during the post-cryopreservation evaluation. Therefore, the best pretreatment was 5% Dimethyl sulfoxide supplemented with 0.09 M l-proline, allowing the most growth recovery of thawed samples and more cotyledonary embryos (maturation ability). The evaluated responses in presence of cryoprotective elements were genotype dependent.