Autolytic activities of the cell wall in rice coleoptiles. Effects of nojirimycin

Oryza sativa L. var. bahia coleoptile cell walls show sufficient autolytic activity for the release into the surrounding medium of amounts up to 60 μg of sugars per mg of dry weight of cell wall. The products released elute in Bio-gel P.2 as mono- and polysaccharides with glucose as the sole component. The polysaccharide component releases tri- and tetrasaccharides on treatment with a glucanase specific for β (1–3) (1–4) linkages in the same proportion as that of the mixed glucan of the cell wall. This supports the hypothesis that the polysaccharide component originates from the cell wall glucan and that autolysis is therefore related to the processes of the loss of rigidity of the cell wall. Nojirimycin (a specific glucanase inhibitor and inhibitor of auxin-induced elongation) decreases autolytic activity of the cell walls, reducing it to 30% of its normal value. Bio-gel P. 2 elution of the products released in autolysis in the presence of nojirimycin shows that only the monosaccharide fraction was affected.     

Metabolism of steroid hormones by Taenia solium and Taenia crassiceps cysticerci

Previous in vitro experiments showed that both, Taenia crassiceps and Taenia solium cysticerci have the ability to metabolize exogenous androstenedione to testosterone. Here we evaluate on the capacity of both cysticerci to synthesize several sex steroid hormones, using different hormonal precursors. Experiments using thin layer chromatography (TLC) showed that both cysticerci were able to produce ³H-hydroxyprogesterone, ³H-androstenedione and ³H-testosterone when ³H-progesterone was used as the precursor. They also synthesized ³H-androstenediol and ³H-testosterone when ³H-dehydroepiandrosterone was the precursor. In addition, both cysticerci interconverted ³H-estradiol and ³H-estrone. These results, strongly suggest the presence and activity of the Δ4 and Δ5 steroid pathway enzymes, 3β-hydroxysteroid dehydrogenase/Δ^5-4 isomerase-like enzyme (3β-HSD), that converts androstenediol into testosterone; and the 17β-hydroxysteroid dehydrogenase that interconverts estradiol and estrone, in both types of cysticerci.     

Diversity in proteinase specificity of thermophilic lactobacilli as revealed by hydrolysis of dairy and vegetable proteins

Ability of industrially relevant species of thermophilic lactobacilli strains to hydrolyze proteins from animal (caseins and β-lactoglobulin) and vegetable (soybean and wheat) sources, as well as influence of peptide content of growth medium on cell envelope-associated proteinase (CEP) activity, was evaluated. Lactobacillus delbrueckii subsp. lactis (CRL 581 and 654), L. delbrueckii subsp. bulgaricus (CRL 454 and 656), Lactobacillus acidophilus (CRL 636 and 1063), and Lactobacillus helveticus (CRL 1062 and 1177) were grown in a chemically defined medium supplemented or not with 1 % Casitone. All strains hydrolyzed mainly β-casein, while degradation of α_s-caseins was strain dependent. Contrariwise, κ-Casein was poorly degraded by the studied lactobacilli. β-Lactoglobulin was mainly hydrolyzed by CRL 656, CRL 636, and CRL 1062 strains. The L. delbrueckii subsp. lactis strains, L. delbrueckii subsp. bulgaricus CRL 656, and L. helveticus CRL 1177 degraded gliadins in high extent, while the L. acidophilus and L. helveticus strains highly hydrolyzed soy proteins. Proteinase production was inhibited by Casitone, the most affected being the L. delbrueckii subsp. lactis species. This study highlights the importance of proteolytic diversity of lactobacilli for rational strain selection when formulating hydrolyzed dairy or vegetable food products.     

Evaluation of AMCase and CHIT-1 expression in monocyte macrophages lineage

Acidic mammalian chitinase (AMCase) and chitotriosidase (CHIT-1) are two active chitinases expressed in humans. The chitinase activity of AMCase was found to be causative in allergic inflammation and its expression was found to be induced by interleukin-13. CHIT1-1 is expressed by phagocytic cells and extremely high levels are seen in lysosomal storage diseases. Despite that AMCase expression in the inflammation is under investigation, little is known regarding its regulation during macrophages' full maturation and polarization. In this study, we compared AMCase and CHIT-1 modulation during monocyte to macrophage transition and polarization. Gene expression analysis was investigated by real-time PCR from mRNA of human monocytes obtained from buffy coat of healthy volunteers, from mRNA of polarized to classically activated macrophages (or M1), obtained by interferon (IFN)-γ and lipopolysaccharide (LPS) treatment, and from mRNA of alternatively activated macrophages (or M2) obtained by interleukin (IL)-4 exposure. Our results showed that the expression of AMCase and CHIT-1 were differently modulated in HMMs at different stage of maturation. The behavior of these two active chitinase suggests that in the immune response their role is complementary.     

Contribution of crop model structure,parameters and climate projections to uncertainty in climate change impact assessments

Climate change impact assessments are plagued with uncertainties from many sources, such as climate projections or the inadequacies in structure and parameters of the impact model. Previous studies tried to account for the uncertainty from one or two of these. Here, we developed a triple‐ensemble probabilistic assessment using seven crop models, multiple sets of model parameters and eight contrasting climate projections together to comprehensively account for uncertainties from these three important sources. We demonstrated the approach in assessing climate change impact on barley growth and yield at Jokioinen, Finland in the Boreal climatic zone and Lleida, Spain in the Mediterranean climatic zone, for the 2050s. We further quantified and compared the contribution of crop model structure, crop model parameters and climate projections to the total variance of ensemble output using Analysis of Variance (ANOVA). Based on the triple‐ensemble probabilistic assessment, the median of simulated yield change was ?4% and +16%, and the probability of decreasing yield was 63% and 31% in the 2050s, at Jokioinen and Lleida, respectively, relative to 1981–2010. The contribution of crop model structure to the total variance of ensemble output was larger than that from downscaled climate projections and model parameters. The relative contribution of crop model parameters and downscaled climate projections to the total variance of ensemble output varied greatly among the seven crop models and between the two sites. The contribution of downscaled climate projections was on average larger than that of crop model parameters. This information on the uncertainty from different sources can be quite useful for model users to decide where to put the most effort when preparing or choosing models or parameters for impact analyses. We concluded that the triple‐ensemble probabilistic approach that accounts for the uncertainties from multiple important sources provide more comprehensive information for quantifying uncertainties in climate change impact assessments as compared to the conventional approaches that are deterministic or only account for the uncertainties from one or two of the uncertainty sources.     

Autolysis of cell walls in pea epicotyls during growth. Enzymatic activities involved

Pisum sativum L. (cv. Lincoln) epicotyl cell walls show autohydrolysis and release into the incubation medium up to 120 μg of sugar per mg of cell wall dry weight in 30 h. Cell walls from younger epicotyls with high growth capacity showed higher auto-lytic capacity than older epicotyls. This suggests that both processes, growth and au-tolysis, are related. The proteins responsible for autolysis were extracted from the wall fraction with high saline solution (3 M LiCl) and enzymatic activities associated with the proteins were studied. The highest activity corresponded to α-galactosidase; lower activities were found for β-galactosidase, a-arabinosidase and exoglucanase. Changes in enzymatic activities and changes in the proportion of sugars released in autolysis by cell walls during the growth of epicotyls support the notion that α-galac-tosidase is one of the enzymes involved in the process of autolysis, and that the liberation of arabinose and galactose in this process occurs as arabinogalactan.     

The muscle ankyrin repeat proteins: CARP, ankrd2/Arpp and DARP as a family of titin filament-based stress response molecules

CARP, ankrd-2/Arpp, and DARP, are three members of a conserved gene family, referred to here as MARPs (muscle ankyrin repeat proteins). The expression of MARPs is induced upon injury and hypertrophy (CARP), stretch or denervation (ankrd2/Arpp), and during recovery following starvation (DARP), suggesting that they are involved in muscle stress response pathways. Here, we show that MARP family members contain within their ankyrin repeat region a binding site for the myofibrillar elastic protein titin. Within the myofibril, MARPs, myopalladin, and the calpain protease p94 appear to be components of a titin N2A-based signaling complex. Ultrastructural studies demonstrated that all three endogenous MARP proteins co-localize with I-band titin N2A epitopes in adult heart muscle tissues. In cultured fetal rat cardiac myocytes, passive stretch induced differential distribution patterns of CARP and DARP: staining for both proteins was increased in the nucleus and at the I-band region of myofibrils, while DARP staining also increased at intercalated discs. We speculate that the myofibrillar MARPs are regulated by stretch, and that this links titin-N2A-based myofibrillar stress/strain signals to a MARP-based regulation of muscle gene expression.