Effects of myenteric denervation on extracellular matrix fibers and mast cell distribution in normal stomach and gastric lesions

Background  

In this study the effect of myenteric denervation induced by benzalconium chloride (BAC) on distribution of fibrillar components of extracellular matrix (ECM) and inflammatory cells was investigated in gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Rats were divided in four experimental groups: non-denervated (I) and denervated stomach (II) without MNNG treatment; non-denervated (III) and denervated stomachs (IV) treated with MNNG. For histopathological, histochemical and stereological analysis, sections of gastric fragments were stained with Hematoxylin-Eosin, Picrosirius-Hematoxylin, Gomori reticulin, Weigert's Resorcin-Fuchsin, Toluidine Blue and Alcian-Blue/Safranin (AB-SAF).     

Extraction of lipase from Aspergillus niger by insoluble complex formation with anionic and cationic polyelectrolytes

The insoluble complex formation between lipase from Aspergillus niger and the electrically charged polymers, polyacrylic acid (PAA), poly-vinil sulfonate (PVS) and chitosan (CHI), was studied by using turbidimetric and enzymatic methods on a commercial lyophilized (Ly) and a filtrate of solid culture medium (SCM). It could be shown that both electrostatic interactions as hydrophobic are involved in the formation of insoluble complexes. The kinetics of the complex formation were determined. Lipase enzymatic activity is maintained through time in the presence of polyelectrolytes.On the Ly the three polymers produced insoluble complex, with a stoichiometric ratio (polymer mass per mass of Ly from Aspergillus niger) of PAA/Ly: 0.035, PVS/Ly: 0.099 and CHI/Ly: 0.071 mg/mg Ly. For the anionic polyelectrolytes, the PAA presents slightly better results than PVS to be used when the protein concentration is similar to the lyophilized.The filtrate of the SCM has a total protein concentration much lower than commercial lyophilized. Working with CHI as cationic polymer a recovery of the activity in the re-dissolved precipitate higher than 80%, with purification factors greater than 3 were achieved, both at 8 and 20 °C. Therefore, this methodology could be used as a first step of purification.     

<Emphasis Type="Italic">Pseudocercospora griseola</Emphasis> Causing Angular Leaf Spot on <Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> Produces 1,8-Dihydroxynaphthalene-Melanin

Pseudocercospora griseola is the causal agent of angular leaf spot of common bean (ALS). It has undergone parallel coevolution with its host and two major groups have been defined, “Andean” (P. griseola f. griseola) and “Mesoamerican” (P. griseola f. mesoamericana). The aim of this study was to analyze the nature and the level of the dark pigment synthesized by the representatives of each group. After 21 days of incubation on potato dextrose agar medium, P. griseola f. griseola isolate S3b developed colonies with diameters of 17.5 ± 1.3 mm and concentric rings of pigmentation. Isolate T4 of P. griseola f. mesoamericana presented smaller colonies (9.9 ± 0.3 mm) with a uniform dark-gray color. Both isolates, S3b and T4, produced the same pigment, a 1,8-dihydroxynaphthalene-melanin, although different in quantity and structural features as suggested by the IR spectrum. The P. griseola f. griseola isolate S3b had a higher growth rate and melanin content as well as smaller sensitivity to melanin synthesis inhibitors compared to the isolate T4 of P. griseola f. mesoamericana. These results suggest a possible link between melanin and growth in P. griseola.     

Modified calibration protocol evaluated in a model-based testing of SBR flexibility

The purpose of this paper is to refine the BIOMATH calibration protocol for SBR systems, in particular to develop a pragmatic calibration protocol that takes advantage of SBR information-rich data, defines a simulation strategy to obtain proper initial conditions for model calibration and provides statistical evaluation of the calibration outcome. The updated calibration protocol is then evaluated on a case study to obtain a thoroughly validated model for testing the flexibility of an N-removing SBR to adapt the operating conditions to the changing influent wastewater load. The performance of reference operation using fixed phase length and dissolved oxygen set points and two real-time control strategies is compared to find optimal operation under dynamic conditions. The results show that a validated model of high quality is obtained using the updated protocol and that the optimization of the system’s performance can be achieved in different manners by implementing the proposed control strategies.     

Genetic characterization of grapevine-infecting Botrytis cinerea isolates from Argentina

BackgroundBotrytis cinerea is an ascomycete with a high genetic diversity and complex population structure, as reported from several hosts and sites. However, nothing is known about its genetic diversity in Argentina.AimsThe aim of this work is to estimate the genetic diversity of a local population of B. cinerea isolates obtained from grapevine in Argentina.MethodsIn this work, 35 strains that had been isolated from grapevines were genotyped for the presence of transposable elements and PCR-based RFLP molecular markers. The obtained results were compared with those from a large French population of the fungus, and used to perform a population genetics analysis using the Genepop software.ResultsAll the analysed isolates were classified as Group II (according to the most recent proposed classification) and showed a high degree of genetic diversity, with 14 different haplotypes. A significant difference in allele frequency was recorded between the local and French populations.ConclusionsThese comparisons between fungal populations, led to the detection of a high level of diversity and the differentiation between local and French groups of isolates. This was confirmed by an Fst value of 0.3332, which was higher than that reported for other pairwise comparisons of populations. This work constitutes the first report on the genetic diversity of B. cinerea isolates and their population structure in Argentina.