A parasitic wasp of stored‐product pests, Anisopteromalus calandrae (Howard), is known to have a sibling species with a different chromosome number. Here, we report establishment and characterization of an eye color mutant in this sibling species. The phenotype of the mutant is red eye in adults, and crossing experiments revealed that the mutant phenotype is recessive to wild type (brown eye color). We also report DNA barcode sequences (a partial sequence of mitochondrial cytochrome‐c oxidase subunit I) of A. calandrae and the sibling species to enable accurate identification of these morphologically similar species. Analyses of our laboratory strains showed that 12.6% of the analyzed sequences (82 of 652 bp) differed between the two species. Finally, we note that the seed beetle Callosobruchus chinensis (Linné) (family Bruchidae), host of our laboratory strains of the sibling species, is a new record of alternative host at the family‐level for the wasp (known hosts: Anobiidae (natural host) and Curculionidae (alternative host)).

To test the existence of the salt bridge and stability of the HIV-1 p17 matrix protein, an E12A (mutated at helix 1) was established to abolish possible electrostatic interactions. The chemical shift perturbation from the comparison between wild type and E12A suggested the existence of an electrostatic interaction in wild type between E12 and H89 (located in helix 4). Unexpectedly, the studies using urea denaturation indicated that the E12A substitution slightly stabilized the protein. The dynamic structure of E12A was examined under physiological conditions by both amide proton exchange and relaxation studies. The quick exchange method of amide protons revealed that the residues with faster exchange were located at the mutated region, around A12, compared to those of the wild-type protein. In addition, some residues at the region of helix 4, including H89, exhibited faster exchange in the mutant. In contrast, the average values of the kinetic rate constants for amide proton exchange for residues located in all loop regions were slightly lower in E12A than in wild type. Furthermore, the analyses of the order parameter revealed that less flexible structures existed at each loop region in E12A. Interestingly, the structures of the regions including the alpha1-2 loop and helix 5 of E12A exhibited more significant conformational exchanges with the NMR time-scale than those of wild type. Under lower pH conditions, for further destabilization, the helix 1 and alpha2-3 loop in E12A became more fluctuating than at physiological pH. Because the E12A mutant lacks the activities for trimer formation on the basis of the analytical ultra-centrifuge studies on the sedimentation distribution of p17 (Fledderman et al. Biochemistry 49, 9551–9562, 2010), it is possible that the changes in the dynamic structures induced by the absence of the E12-H89 interaction in the p17 matrix protein contributes to a loss of virus assembly.