Evaluation of the Antioxidant Activity of Cell Extracts from Microalgae

A growing market for novel antioxidants obtained from non-expensive sources justifies educated screening of microalgae for their potential antioxidant features. Characterization of the antioxidant profile of 18 species of cyanobacteria (prokaryotic microalgae) and 23 species of (eukaryotic) microalgae is accordingly reported in this paper. The total antioxidant capacity, accounted for by both water- and lipid-soluble antioxidants, was evaluated by the (radical cation) ABTS method. For complementary characterization of cell extracts, a deoxyribose assay was carried out, as well as a bacteriophage P22/Salmonella-mediated approach. The microalga Scenedesmus obliquus strain M2-1 exhibited the highest (p > 0.05) total antioxidant capacity (149 ± 47 AAU) of intracellular extracts. Its scavenger activity correlated well with its protective effects against DNA oxidative damage induced by copper(II)-ascorbic acid; and against decay in bacteriophage infection capacity induced by H₂O₂. Finally, performance of an Ames test revealed no mutagenic effects of the said extract.     

A comparative study of an indirect fluorescent antibody test and an immunoperoxidase monolayer assay for the diagnosis of porcine proliferative enteropathy.

The currently used indirect fluorescent antibody test (IFAT) for the detection of antibodies against porcine proliferative enteropathy (PPE) was compared to an immunoperoxidase monolayer assay (IPMA). Serum samples used in this comparison were collected from 5-week-old pigs on day 0 (pre-experimental challenge) and on days 7, 14, 21, and 28 after oral inoculation with intestinal homogenate from pigs affected by PPE (28 challenged pigs) and sucrose phosphate glutamate solution (2 control pigs). All animals were euthanized 4 weeks after inoculation. Immunohistochemistry staining was applied to formalin-fixed, paraffin-embedded sections of ileum for the detection of Lawsonia intracellularis antigen. The serology results with each method agreed in all samples, except on days 0 and 7 in 1 control animal, which was positive by IPMA, but negative by IFAT. The percentage of agreement between IFAT and IPMA was 98.6%.     

Designing artificial anterior cruciate ligaments based on novel fibrous structures

The present paper reports the development of novel braided structures using polyamide 6.6 fibers for application as artificial anterior cruciate ligaments (ACLs). The developed structures were circular braids, axially reinforced with either a number of core yarns or braided structures. Tensile behavior of these structures was characterized and the effects of number of axial yarns or braids and, the number of yarns used in the axial braids were thoroughly investigated. From the experimental results, it was observed that the braided structures with axial braids could mimic the load-elongation behaviour of native ACL. The average breaking extension and strain at toe region were 30 % and 4.3 % respectively, which are in the range of native ACLs. The maximum breaking force and stiffness achieved with 7 axial braids, each produced using 6 yarns were 274 N and 13.5 N/mm respectively and, both breaking force and stiffess showed linear increase with the number of axial braids as well as number of yarns used in the axial braids. Therefore, it is possible to design an artificial graft using these novel braided sturctures with mechanical properties similar to that of native ACLs, through adjustment of these structural parameters, as these braided structures have much smaller diameter (0.5 mm) than native ACLs (11 mm).     

Protein digestibility, protease activity, and post-embryonic development of the velvetbean caterpillar (Anticarsia gemmatalis) exposed to the trypsin-inhibitor benzamidine

Protein digestibility, proteolytic activity, and post-embryonic development of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) were assessed in larvae reared on artificial diet containing 0.00, 0.25, 0.50, and 0.75% (w/w) of the synthetic trypsin inhibitor benzamidine. Diet consumption was affected by the inhibitor when the insects were exposed to 0.50% benzamidine showing a 4-day delay and a 70%-higher peak of consumption. Larva weight gain was also affected by benzamidine and again the results of 0.50% benzamidine were unexpected due to the worst performance of the insects at this inhibitor concentration and not at 0.75% benzamidine. These patterns of consumption and weight gain were however consistent with the results of protein digestibility, which affects larvae mortality and adult emergence. The insect proteolytic activity was also affected by benzamidine, particularly at 0.50%. These results indicate that the insects are able to circumvent the potentially harmful effects of the inhibitor since at the highest concentration the negative impact is mitigated.