Perspectives of digestive pest control with proteinase inhibitors that mainly affect the trypsin-like activity of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae)

The present study describes the main characteristics of the proteolytic activities of the velvetbean caterpillar, Anticarsia gemmatalis Hübner, and their sensitivity to proteinase inhibitors and activators. Midguts of last instar larvae reared on an artificial diet were homogenized in 0.15 M NaCl and centrifuged at 14,000 g for 10 min at 4ºC and the supernatants were used in enzymatic assays at 30ºC, pH 10.0. Basal total proteolytic activity (azocasein hydrolysis) was 1.14 ± 0.15 absorbance variation min-1 mg protein-1, at 420 nm; basal trypsin-like activity (N-benzoyl-L-arginine-p-nitroanilide, BApNA, hydrolysis) was 0.217 ± 0.02 mmol p-nitroaniline min-1 mg protein-1. The maximum proteolytic activities were observed at pH 10.5 using azocasein and at pH 10.0 using BApNA, this pH being identical to the midgut pH of 10.0. The maximum trypsin-like activity occurred at 50ºC, a temperature that reduces enzyme stability to 80 and 60% of the original, when pre-incubated for 5 and 30 min, respectively. Phenylmethylsulfonyl fluoride inhibited the proteolytic activities with an IC50 of 0.39 mM for azocasein hydrolysis and of 1.35 mM for BApNA hydrolysis. Benzamidine inhibited the hydrolysis with an IC50 of 0.69 and 0.076 mM for azocasein and BApNA, respectively. The absence of cysteine-proteinases is indicated by the fact that 2-mercaptoethanol and L-cysteine did not increase the rate of azocasein hydrolysis. These results demonstrate the presence of serine-proteinases and the predominance of trypsin-like activity in the midgut of Lepidoptera insects, now also detected in A. gemmatalis, and suggest this enzyme as a major target for pest control based on disruption of protein metabolism using proteinase inhibitors.

Serotonergic modulation of face-emotion recognition

Facial expressions of basic emotions have been widely used to investigate the neural substrates of emotion processing, but little is known about the exact meaning of subjective changes provoked by perceiving facial expressions. Our assumption was that fearful faces would be related to the processing of potential threats, whereas angry faces would be related to the processing of proximal threats. Experimental studies have suggested that serotonin modulates the brain processes underlying defensive responses to environmental threats, facilitating risk assessment behavior elicited by potential threats and inhibiting fight or flight responses to proximal threats. In order to test these predictions about the relationship between fearful and angry faces and defensive behaviors, we carried out a review of the literature about the effects of pharmacological probes that affect 5-HT-mediated neurotransmission on the perception of emotional faces. The hypothesis that angry faces would be processed as a proximal threat and that, as a consequence, their recognition would be impaired by an increase in 5-HT function was not supported by the results reviewed. In contrast, most of the studies that evaluated the behavioral effects of serotonin challenges showed that increased 5-HT neurotransmission facilitates the recognition of fearful faces, whereas its decrease impairs the same performance. These results agree with the hypothesis that fearful faces are processed as potential threats and that 5-HT enhances this brain processing.

Modulation of peritoneal macrophage activity by the saturation state of the fatty acid moiety of phosphatidylcholine

To determine the effects of saturated and unsaturated fatty acids in phosphatidylcholine (PC) on macrophage activity, peritoneal lavage cells were cultured in the presence of phosphatidylcholine rich in saturated or unsaturated fatty acids (sat PC and unsat PC, respectively), both used at concentrations of 32 and 64 µM. The treatment of peritoneal macrophages with 64 µM unsat PC increased the production of hydrogen peroxide by 48.3% compared to control (148.3 ± 16.3 vs 100.0 ± 1.8%, N = 15), and both doses of unsat PC increased adhesion capacity by nearly 50%. Moreover, 64 µM unsat PC decreased neutral red uptake by lysosomes by 32.5% compared to the untreated group (67.5 ± 6.8 vs 100.0 ± 5.5%, N = 15), while both 32 and 64 µM unsat PC decreased the production of lipopolysaccharide-elicited nitric oxide by 30.4% (13.5 ± 2.6 vs 19.4 ± 2.5 µM) and 46.4% (10.4 ± 3.1 vs 19.4 ± 2.5 µM), respectively. Unsat PC did not affect anion production in non-stimulated cells or phagocytosis of unopsonized zymosan particles. A different result pattern was obtained for macrophages treated with sat PC. Phorbol 12-miristate 13-acetate-elicited superoxide production and neutral red uptake were decreased by nearly 25% by 32 and 64 µM sat PC, respectively. Sat PC did not affect nitric oxide or hydrogen peroxide production, adhesion capacity or zymosan phagocytosis. Thus, PC modifies macrophage activity, but this effect depends on cell activation state, fatty acid saturation and esterification to PC molecule and PC concentration. Taken together, these results indicate that the fatty acid moiety of PC modulates macrophage activity and, consequently, is likely to affect immune system regulation in vivo.

Storage stability of cashew apple juice preserved by hot fill and aseptic processes

Cashew (Anacardium occidentale L.) apples from Pacajus, Ceará State, Brazil, were processed into high pulp content juice. The juice was packed either by hot fill or an aseptic process and evaluated for physical, physical-chemical, and sensorial changes during a 12-month storage period at room temperature. The results indicated that pH, soluble solids, total acidity, total sugar content and color did not change significantly during storage nor were affected by the type of filling. The sensorial analysis showed that juice acceptance remained high throughout the storage period regardless of the filling system. Differences in juice viscosity persisted between both processes.

Type of dietary lipids and storing time on egg stability

The objective of this work was to evaluate the influence of diets containing different lipid sources on eggs quality during refrigerated storage, on yolk fatty acid composition, and on cholesterol in the yolk. Four diets were used containing Soy Oil (SO), Sunflower Seed (SS), and Meat and Bone Meal + Soy Oil (MBM + SO) or Meat and Bone Meal + Tallow (MBM + TA). The experiment followed a factorial design 4 × 3 with four dietary treatments and three storage times. The eggs were stored at 4 °C for 0, 30, and 60 days. The collected eggs were analyzed for egg weight loss, Haugh units, yolk moisture, yolk lipid oxidation, and cooked yolk firmness. Refrigerated storage reduced Haugh units, and increased yolk moisture. Sixty days of storage time reduced the firmness of hard-cooked yolk. There was an interaction between dietary treatment and storage time for egg weight loss and lipid oxidation. With regard to yolk fatty acid profile, MBM + TA diet increased the contents of palmitic and palmitoleic acids. The levels of oleic and arachidonic acids were higher in yolks from birds fed with SS diet. Linoleic acid level was higher in the yolk from treatment with SO diet. Diets containing MBM + SO induced higher levels of docosahexaenoic acid. Yolk cholesterol content was reduced with the inclusion of SS in the diet. Therefore, the type of lipid present in the diet and refrigerated storage for 60 days at 4 °C can affect the egg quality.

Downstream processing of pectinase produced by Aspergillus niger in solid state cultivation and its application to fruit juices clarification

In this work, a protocol for the formulation of an enzyme concentrated product to be applied in fruit juice treatment is described. Downstream processing conditions for the recovery and concentration of pectinases produced by the new strain Aspergillus niger LB-02-SF in solid state cultivation were assessed. The solid-liquid ratio in the extraction step of pectinases recovery from the cultivated media was evaluated and the highest activity was obtained with a solid-liquid ratio of 1:10. The crude extract was concentrated by ultrafiltration and the total pectinase (TP) activity was 73.6-fold concentrated in relation to the crude extract, and a final TP titer of 663 U mL–1 was obtained with 73.7% of recovery yield. KCl and different glycerol concentrations were added to the concentrated extract and the stability of pectinases during the storage at 5°C for 59 weeks was tested. The formulation with 50% w/w glycerol was applied to the treatment of apple and grape juices and the results of these tests were statistically comparable to those obtained with two high-quality commercial preparations.