Selection and molecular identification of fungal isolates that produce xylanolytic enzymes.

Xylan is a heteropolysaccharide and its complete hydrolysis involves a complex set of xylanolytic enzymes. Fungal xylanases have been widely used in the holocellulose industry to obtain by-products or for its elimination. The aim of this study was to select and identify filamentous fungi from different ecosystems that produce extracellular xylanases showing biotechnological potential. One hundred three fungal isolates were obtained from orchard, horticultural, and forest ecosystems. The ability of fungi to degrade xylan was measured by quantifying their xylanolytic indices after growth on solid culture media and their extracellular xylanolytic and cellulolytic activities after submerged fermentation. All fungal isolates grew on solid medium supplemented with xylan as the sole carbon source, but only 44% of isolates showed xylanolytic indices greater than 1.0. In submerged fermentation, 39% of the fungi tested showed no cellulolytic activity. Filamentous fungi were chosen from correspondence analysis and were identified by molecular tools using internal transcribed spacers. One of the 9 isolates selected belonged to the Phoma genus and the remaining were from the Fusarium genus. Fusarium solani (isolate 59) showed the highest xylanolytic index (0.964 ± 0.042), rapid growth on solid medium (1.233 ± 0.050 cm/day), significant xylanolytic activity (3.823 ± 0.210 U/mg), and a total deficiency of cellulolytic activity compared to other fungal isolates. In the zymogram, a clear zone was observed, indicating that F. solani possesses at least 1 xylanase. Fusarium solani was selected for its ability to produce extracellular xylanases with biotechnological potential.

Deletion mapping and paternal origin of a Mexican AMELY negative male.

The amelogenin represents the gender marker most widely used for human identification and biomedical purposes. However, some failures in sex-typing have been observed globally. In this study, we could approximate the population frequency of AMELY negative males in 1230 individuals from five states of Mexico (0.081%). For the sole AMELY negative male detected, we constructed a deletion map by means of 10 markers (7 STS and 3 Y-STRs). This allowed classifying the case into the most common category (Class I deletion), according to the nomenclature proposed by Jobling et al. (2007). Interestingly, the Mexican sample was R1a1(∗), a Y-chromosome haplogroup non-previously reported for AMELY negative cases. The geographic distribution of R1a1(∗), and the Y-STR haplotype similarity with a reported case from Slovenia, suggests an Eastern-Europe paternal origin for this case from Mexico. To our knowledge, this is the first report in Latin America that implies a low population frequency and European paternal origin of AMELY negative cases.

A leptin serum concentration less than 10 ng/ml is a predictive marker of outcome in patients with moderate to severe secondary peritonitis.

INTRODUCTION: Leptin is involved in the sepsis syndrome. A possible relationship exists between low leptin levels and peritonitis severity and a poorer prognosis. OBJECTIVES: We aimed to corroborate the relationship between low leptin serum levels and death in patients with peritonitis and to explore the associations between leptin and interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-13 (IL-13), tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein (CRP). METHODS: In 230 adult patients with surgically confirmed secondary peritonitis, the Mannheim Peritonitis Index and the serum concentrations of leptin, IL-6, IL-10, IL-13, TNF-alpha and CRP were determined. Two cohorts were established (leptin < or = 10 ng/ml and > 10 ng/ml). Death or survival was followed through 30 days. The relationship between leptin (< or = 10 ng/ml) and death was evaluated using the accumulated incidence ratio (AIR). The association of leptin (dependent variable) with IL-6, IL-10, IL-13, TNF-alpha and CRP (independent variables) was studied by regression analysis. RESULTS: The general mortality rate was 7.8% and the death AIR was 3.15 (p nonsignificant). A subsample of patients with a Mannheim Peritonitis Index > or = 21 was studied, showing a significant AIR of 4.26 (p = 0.017). Regression analysis determined an association only between leptin and IL-6 (p < 0.001), IL-10 (p < 0.047) and CRP (p < 0.001). DISCUSSION: A serum leptin below the threshold of 10 ng/ml is an adverse prognostic marker in patients with moderate to severe secondary peritonitis. The results of the regression analysis suggest that the mechanisms involved are opposing, in that leptin associated with IL-6 has a proinflammatory effect and, through IL-10 and CRP production, restrains the inflammatory response.