Morphological, Biological, and Molecular Characterization of Type I Granuloviruses of Spodoptera frugiperda.

Granuloviruses (GVs) Betabaculovirus associated with the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), especially those of the type I, have scarcely been studied. These GVs might be an effective alternative for the biocontrol of this insect. In this study, the native GVs SfGV-CH13 and SfGV-CH28 were isolated from FAW larvae and characterized for morphology, molecular traits, and insecticidal activity. The elapsed time between symptomatic infection of larvae and stop feeding as well as the weight of larvae before death or prior to pupation were also evaluated. Both GVs had ovoid shape and a length of 0.4 µm. They had the same DNA restriction profiles and their genome sizes were about 126 kb. The symptomatic infection with the tested GVs mainly caused flaccidity of larva body and discoloration of integument. The integument lysis was only observed in 8% of infected larvae. Infected larvae gradually stopped feeding. Overall, these symptoms are characteristic of infections caused by type I GVs, which are known as monoorganotropic or slow-killing GVs. The median lethal dose (LD50) values for SfGV-CH13 and SfGV-CH28 isolates were 5.4 × 102 and 1.1 × 103 OBs/larva, respectively. The median lethal time (LT50) ranged from 17 to 24 days. LT50 values decreased as the viral dose was increased. The elapsed time from symptomatic infection until pupation and body weight of larvae (third instar) were higher with SfGV-CH28 than SfGV-CH13. Both granulovirus isolates were able to kill the FAW larvae from the 12th day.

Characterization of insect chitosan films from Tenebrio molitor and Brachystola magna and its comparison with commercial chitosan of different molecular weights.

Insects are considered as alternative sources of chitosan; however, studies about the functional film-forming properties of insect chitosan are scarce. Insect chitosan films were made from Tenebrio molitor and Brachystola magna and were compared with commercial chitosan of different molecular weights (Mw). Mechanical properties (tensile strength, TS; elastic modulus, EM; elongation at break, %E), water vapor permeability (WVP) and physicochemical properties were characterized. The film properties of both commercial and insect chitosan were affected by Mw. Commercial chitosan films showed that at lower Mw, the TS (from 59 to 48 MPa) and EM (from 1471 to 1286 MPa) decreased; whereas WVP (from 2.9 × 10-11 to 3.4 × 10-11 g m-1s-1Pa-1), % E (from 38 to 41%) and solubility (from 30 to 33%) increased. Chitosan insect films showed lower TS and EM, and higher WPV, %E and solubility than commercial films. SEM revealed that chitosan insect films had lower porosity than commercial films. FTIR and X-ray diffraction showed not difference between insect and commercial chitosan films. These results showed that T. molitor and B. magna chitosan films could be used as a packaging material in several food products.

Antioxidant activity and content of chlorophylls and carotenoids in raw and heat-processed Jalapeño peppers at intermediate stages of ripening.

Jalapeño peppers at intermediate ripening stages (IRS) are typically discarded at the packinghouse because they are not demanded for fresh consumption or industrial processing. These peppers have been scarcely studied in terms of pigment composition and bioactivity. In this study, the profile of pigments (carotenoids and chlorophylls) and antioxidant activity were determined in raw and heat-processed Jalapeño peppers at three IRS (brown, 50% red, and 75% red). Peppers contained 64 different pigments. Chlorophylls were the most abundant pigments in raw brown peppers while capsanthin was the most abundant at the other IRS. The content of most pigments decreased due to heat treatments. Several pheophytins and cis isomers of carotenoids were generated by heat processing. Boiling and grilling consistently decreased and increased the antioxidant activity of peppers, respectively. Tested peppers showed a more complex/abundant pigment content and higher antioxidant activity than those typically reported for green and red peppers.