Immunohistochemical detection of extrinsic and intrinsic mediators of apoptosis in porcine paraffin-embedded tissues

Apoptosis is a strictly regulated mechanism of cell death that involves a complex network of biochemical pathways. Whether a cell undergoes apoptosis or not depends on a delicate balance of anti- and pro-apoptotic stimuli. This phenomenon can be induced by two different pathways: intrinsic and extrinsic pathways. The main aim of this study was to determine the ideal fixative and antigen retrieval method in porcine paraffin embedded tissues for the immunohistochemical detection of apoptosis mediators, from both extrinsic and intrinsic pathways. Tonsil, retropharyngeal lymph node and lung tissue samples were fixed in 10% neutral buffered formalin, Bouin solution and zinc salts fixative (ZSF) and different unmasking methods were carried out. Both 10% neutral buffered formalin and ZSF resulted as the fixatives of election to study apoptosis phenomena. Tween 20 (0.01% in PBS), citrate buffer (microwave, pH 6.0) and/or protease type XIV were the antigen retrieval methods which displayed better labelling. Our results allow to deep in the knowledge of apoptosis and its role in the pathogenesis of porcine diseases.     

Determination of the Bioavailable Fraction of Cu and Zn in Soils Amended with Biosolids as Determined by Diffusive Gradients in Thin Films (DGT), BCR Sequential Extraction, and Ryegrass Plant

This study assessed the effect of biosolids applied at rates, 0, 30, 45, and 60?Mg?ha^?1 on the chemical associations and bioavailability of Cu and Zn in soils from an important agricultural zone of the Metropolitan Region in Central Chile. Three methods were used to determine the bioavailability of Cu and Zn in soils: ryegrass (Lolium perenne) plants, diffusive gradients in thin films (DGT) technique, and Community Bureau of Reference (BCR) sequential extraction. The DGT effective concentration (C _E) and sequential extract acid soluble fraction of the BCR extraction (most labile fraction of the soils, normally associated with bioavailability) were compared with total metal concentration in ryegrass plants as a means to compare the chemical and biological measures of bioavailability. Total Zn was higher in comparison to Cu for all treatments. Concentrations were within the limits set by the Chilean regulations for land-applied biosolids. Metals in the control soil were primarily found in the residual fraction of soils. Biosolids application generally decreased this fraction, with a subsequent increase observed mainly in the acid soluble fraction. The contents of Cu and Zn in ryegrass plants increased with increasing rates of biosolids. Comparison of the Cu and Zn content in ryegrass plants with C _E, showed a good correlation for Zn. However, the C _E for soil Cu was only related to plant Cu for some of the soils studied. Correlation between Zn in ryegrass plants and the labile fraction of Zn as measured by the sequential extraction was excellent, with correlation coefficients >0.9, while for Cu, correlation coefficients were lower.     

Coinfection by Cryptosporidium parvum and Porcine Circovirus Type 2 in Weaned Pigs

Routine histopathological diagnosis of one representative 3‐month‐old pig from a group suffering from diarrhoea revealed a massive degree of parasitation by Cryptosporidium parvum, with a concomitant infection by porcine circovirus type 2 (PCV2), that was confirmed by immunohistochemical procedures. The areas of intestine where parasites were more numerous presented abundant PCV2 infected cells in mucosa and submucosa. The concurrence of C. parvum, a rare primary intestinal pathogen in post‐weaning and growing pigs, and PCV2 infections suggest an increased susceptibility as a result of an immunosuppression state.     

Differential Growth Response and Minituber Production of Three Potato Cultivars Under Aeroponics and Greenhouse Bed Culture

We have evaluated and compared different methods and cultivars for the production of quality prebasic seed in potato. Two cultivation systems, aeroponics and greenhouse beds with a peat moss substrate, and three potato cultivars with different vegetative cycle, Agria, Monalisa and Zorba, were assayed. Plants in the aeroponic system showed increased growth and their vegetative cycle extended between 12 and 36 % compared to the plants cultivated in greenhouse beds. Flowering and tuberization dates, Absolute Growth Rates (AGR) during the period of 60 days after planting (DAP) and height presented a wide variation between cultivars. Zorba showed earlier flowering and tuberization, lower AGR and reached a minor height at 60 DAP. Instead the late season cultivar Agria showed later flowering and tuberization, presented higher AGR and reached an increased height at 60 DAP. The total tuber yield per plant was between 34 and 87 % higher in the aeroponic system, with a marked difference for the earlier cultivars Zorba and Monalisa. Tuber numbers increased between 60 and 80 %. Minituber production in aeroponics showed a better size distribution, with a reduction in the percentage of tubers smaller than 12 mm of between 33 and 86 %. In this soil-less culture system average tuber weight increased in Zorba and Monalisa over 60 % but was lower for Agria. Further studies are needed to optimize aeroponics system, which can be considered a high yield potato multiplication system, particularly for early or mid season potato cultivars that may produce best quality minitubers.     

Genetic structure of highland papayas (<Emphasis Type="Italic">Vasconcellea pubescens</Emphasis> (Lenné et C. Koch) Badillo) cultivated along a geographic gradient in Chile as revealed by Inter Simple Sequence Repeats (ISSR)

In Chile Vasconcellea pubescens is cropped to produce canned fruit, juice, jam and processed sweets. Additionally this species produces latex with a high level of papain, an important and valuable proteolytic enzyme with industrial applications. In this investigation seven ISSR primers were used to study the level and organization of genetic diversity in 333 samples of V. pubescens. Out of the 114 bands recorded, 63 proved to be polymorphic (P = 55.3%). At the species level, the genetic diversity was rather low (h = 0.01 ± 6,80188E-05, Shannon’s Index I = 0.16 ± 0,000148). The major portion of the genetic diversity was found within groups (65%). The genetic differentiation between the different groups was significant, as the AMOVA analysis suggested (Φ_pt = 0.35). When analysing the Northern area alone, the differentiation increased to Φ_pt = 0.40. When only the Southern area was analysed, Φ_pt decreased to 0.18, indicating greater genetic similarity among the samples. The results generated from Structure and Bayesian Analysis of Population Structure distinguished 8 genetically different groups, five of them located in the north and three in the south. The results are discussed in the light of the growers’ practices.     

Marker-assisted Breeding for Disease Resistance in Potato

Sub-project 5 of BIOEXPLOIT aims to design durable disease resistance through marker-assisted breeding by converting existing markers for high-throughput application, developing and validating high-throughput marker technologies and pyramiding major R genes and/or quantitative trait loci into elite material. Activities include (1) the fine mapping of the quantitative trait locus PiXspg which accounts for a large proportion of the variation in late blight resistance, (2) converting SNP-based markers and an AFLP marker to easy-to-use-markers, (3) testing of progenies with combined sources of late blight resistance for presence of R genes and agronomic features, (4) backcrossing new sources of resistance to S. tuberosum and molecular screening of breeding materials with marker GP94 linked with gene Rpi-phu1 conferring late blight resistance, (5) evaluating potato clones with enhanced resistance against Phytophthora infestans under field conditions of Toluca (México), and (6) developing populations and marker-assisted breeding for disease resistance.     

Control of dry bubble disease (Lecanicillium fungicola) in button mushroom (Agaricus bisporus) by spent mushroom substrate tea

Dry bubble (caused by Lecanicillium fungicola) is a widespread disease of button mushroom. The objective of the experiments was to determine the efficacy of compost teas made from spent mushroom substrate (SMS) as a biocontrol method against the disease. All SMS teas produced in this study significantly inhibited (100 %) the in vitro mycelial growth of L. fungicola, whereas the fungicide prochloraz at 50 ppm inhibited growth by 91 %. The in vivo effectiveness of two SMS aerated teas, one with mineral soil (MS) and the other with peat (TPT), was evaluated in two mushroom cropping trials inoculated with L. fungicola. The results demonstrated that the most effective treatments were those with TPT applied close to harvest and/or those with the greatest number of applications. The most efficacious treatments were TPT treatments (reducing disease by 34 to 73 % in the two trials, compared to the inoculated control). In contrast, prochloraz reduced disease by 7 % and 4 % in the two trials, compared to the control. These results suggest that dry bubble disease can be controlled by the use of spent mushroom substrate teas.     

Breadmaking Use of Andean Crops Quinoa,Kañiwa,Kiwicha, and Tarwi

The effect of addition of flours from the highly nutritious Andean crops quinoa (Chenopodium quinoa), kañiwa (Chenopodium pallidicaule), kiwicha (Amaranthus caudatus), and tarwi (Lupinus mutabilis) has been investigated in wheat doughs and fresh bread quality. The thermomechanical profile of wheat doughs and bread quality has been explored by increasing substitution of wheat flour at 0–100% by Andean crop flours. Dough blends were evaluated using the Chopin Mixolab device, whereas bread quality assessment comprised sensory (overall acceptability) and physicochemical (moisture, specific volume, texture, color) determinations in composite breads. In general, no breads with aerated crumb structure could be obtained from 100% Andean crop flours, with the exception of quinoa breads that had overall sensory values about half a completely perfect score, and which were not significantly different from the breads made from a 50:50 blend of wheat and quinoa. Replacement of wheat flour by ≤12.5% (tarwi), 25% (kañiwa), and 50% (kiwicha), respectively, still produced breads with good sensory acceptability but variable color and doughs with acceptable thermomechanical patterns. Partial substitution of wheat flour by Andean crop flours constitutes a viable option to improve the nutritional value of the breads, with acceptable technological performance of dough blends and composite breads.     

Secondary Metabolites Isolated from Chilean Marine Algae: A Review

Chile is in the extreme southwestern part of America, and it has an extreme length, of approximately 4300 km that increases to 8000 km considering the Chilean Antarctic Territory. Despite the large extent of its coastal territory and the diversity of geographic environments and climates associated with Chilean coasts, the research on marine resources in Chile has been rather scarce. From marine organisms found in Chilean coastal waters, algae have been the most studied, since they contain a wide range of interesting secondary metabolites that have some structural traits that make them unique and uncharacteristic. Thus, a wide structural variety of natural products including terpenoids (monoterpenes, sesquiterpenes, diterpenes, and meroterpenoids), furanones, and C₁₅-acetogenins have been isolated and identified. This review describes the existing literature on bioprospecting and exploration of secondary metabolites from Chilean coasts.