Polarization Microscopy and Infrared Microspectroscopy of Integument Coverings of Diapausing Larvae in Two Distantly Related Nonsocial Bees

Abstract

The larvae of the two distantly related nonsocial bees Ericrocis lata (Apidae) and Hesperapis (Carinapis) rhodocerata (Melittidae), which develop mostly under arid desert areas of North America, and that differ in that they either spin (E. lata) or do not spin (H. rhodocerata) protective cocoons before entering diapause, produce transparent films that cover the larval integument. To understand the nature of these films, their responses to topochemical tests and their characteristics when examined with fluorescence and high-performance polarization microscopy and microspectroscopy were studied. A positive staining by Sudan black B, birefringence of negative sign, and a Fourier transform-infrared (FT-IR) spectrum typical of lipids were detected for the integument covering of both species. The FT-IR signature, particularly, suggests a wax chemical composition for these lipid coverings, resembling the waxes that are used as construction materials in the honey cells produced by social bees. Considering the arid environmental conditions under which these larvae develop, we hypothesize that their covering films may have evolved as protection against water depletion. This hypothesis seems especially appropriate for H. rhodocerata larvae, which are capable of undergoing a long diapause period in the absence of a protective cocoon.

Remodelação estrutural de tendão e caracterização fenotípica de tenócitos em cultura primária do tendão calcanear de ratos

“…Além disso, vem sendo utilizado em estudos de sedas, ceras e mucinas produzidas por abelhas (Mello e Vidal, 1971, 1979Mello 1979Mello , 1982Mello e Garófalo, 1986;Mello et al, 1987;Rozen e Mello, 2014;Mello et al, 2016;Mello et al, 2018).…”

“…Desta forma, as diferenças de caminho óptico puderam ser detectadas pelo deslocamento do prisma posicionado sob o analisador e as cores interferenciais resultantes puderam ser comparadas com aquelas presentes na escala de cores de Michel-Lévy (Vidal et al, 2015). Tal metodologia, em associação com a visualização da birrefringência, tem sido utilizada para descrever com profundidade a ordem quiral supramolecular de cristais de DNA, complexos colágeno-DNA e mesmo, para auxiliar na melhor compreensão da estrutura e composição molecular de casulos de abelhas, provando assim sua ampla e avançada aplicação (Mello et al, 2016;Vidal e Mello, 2017;Mello et al, 2018, Vidal e Mello, 2019b.…”