Spatial distribution of digestive proteinases in the midgut of the Pacific white shrimp (Litopenaeus vannamei) indicates the existence of endo-ectoperitrophic circulation in crustacea - Alexandre, Daniel; Ozório, Renata A; Derner, Roberto B; Fracalossi, Débora Machado; Oliveira, Gabriel Braga; Samuels, Richard Ian; Terra, Walter Ribeiro; Silva, Carlos P (Comparative Biochemistry and Physiology, Part B, 2014)