Simple Summary Fishmeal is an important but costly and limited protein ingredient in shrimp feed. Clostridium autoethanogenum protein is a promising alternative, yet high-level inclusion levels may adversely affect shrimp growth and health. This study evaluated whether dietary curcumin supplementation in Penaeus vannamei fed a diet in which 50% of the fishmeal was replaced with CAP. Three experimental groups were designed in this study: a fishmeal control, a high-CAP diet, and the same high-CAP diet supplemented with curcumin. After eight weeks, shrimp fed the high-CAP diet showed reduced growth, adverse histological changes in the intestine and hepatopancreas, lower nonspecific immune enzyme activities, and alterations in intestinal microbial community composition. Compared with the high-CAP group, curcumin supplementation was associated with improvements in growth performance, tissue morphology, immune enzyme activities, and intestinal microbial profiles. Transcriptomic analysis suggested that identified changes were associated with metabolic and immune-related biological processes. Because a fishmeal-based diet supplemented with curcumin was not included, these findings should be interpreted specifically under high-CAP dietary conditions. Overall, the results support the potential application of curcumin as a functional feed additive in CAP-based, low-fishmeal diets for shrimp.
Bacterial outer membrane proteins (OMPs) are critical players in host-pathogen interactions and environmental adaptation. Here we describe the newly developed "Gradient Enrichment of Native Targets from Lipid Environments" (GENTLE) methodology and use this approach to elucidate the structures of Campylobacter jejuni OMPs directly from native, detergent-solubilized crude membranes. We identify and solve high-resolution cryo-EM structures of PorA, OMP50, and Cj0034c from C. jejuni membranes, all of which are required for Campylobacter invasion, adhesion, and initiation of host infection. Notably, our results provide the first structural information of OMP50, revealing a two-domain architecture constructed with an all β-stranded transmembrane domain and an all α-helical periplasmic domain. This structure depicts that all tyrosine residues, many of which are expected to be critical for phosphorylation and host-pathogen interaction, are localized to the outer membrane of C. jejuni. Our studies also led to the first structure of the full-length Cj0034c protein, which assembles as a nonamer with each protomer containing a single-spanning transmembrane helix and a large periplasmic domain. The nine protomers stack side-by-side to form a channel that spans the entire lipid bilayer. However, whether Cj0034c spans the outer membrane (OM) or inner membrane (IM) of C. jejuni must await further experimental studies. In addition, we observed that the surface-exposed extracellular loop L4 of PorA is very flexible, which may be critical for the virulence of this porin. Collectively, this work provides novel structural information for functionally important OMPs and sheds light on how they assemble in native bacterial membranes. These findings further demonstrate that it is possible to obtain high-resolution structural information for targeted membrane proteins from crude native membranes without their overexpression and purification.
Zhemin Zhang, William D Gregor, M. Ilgu et al.· PLoS Biology· 0 citations
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