Surface lipoproteins (SLPs) are peripherally attached to the outer leaflet of the outer membrane in many Gram-negative bacteria, playing significant roles in nutrient acquisition and immune evasion in the host. While the factors that are involved in the synthesis and delivery of SLPs in the inner membrane are well characterized, the molecular machinery required for the movement of SLPs to the surface are still not fully elucidated. In this study, we investigated the translocation of a SLP TbpB through a Slam1-dependent pathway. Using purified components, we developed an in vitro translocation assay where unfolded TbpB is transported through Slam1-containing proteoliposomes, confirming Slam1 as an outer membrane translocon. While looking to identify factors to increase translocation efficiency, we discovered the periplasmic chaperone Skp interacted with TbpB in the periplasm of Escherichia coli. The presence of Skp was found to increase the translocation efficiency of TbpB in the reconstituted translocation assays. A knockout of Skp in Neisseria meningitidis revealed that Skp is essential for functional translocation of TbpB to the bacterial surface. Taken together, we propose a pathway for surface destined lipoproteins, where Skp acts as a holdase for Slam-mediated TbpB translocation across the outer membrane.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

No abstract

Pterygoplichthys spp. is an invasive alien species distributed in most water bodies of southern Vietnam. Pre-matured fish (70 - 188 mm in length) were sampled from Am Chua canal (12o17.436' N, 109o6.063' E) in Khanh Hoa province, Vietnam and analyzed for reproductive and growth characteristics. Morphology analysis of gonad of these fish indicated that sex of small fish (≈ 8 cm in length, 4 g in weight) could be distinguished using naked eyes. Male to female ratio for the population was 1:1. Weight of gonad at stage I was significantly smaller those at stage II (both collected at the same and different sampling period). Fish at pre-matured stage tended to grow in length more than in weight (b<3). Research results indicated that this species had diverse reproductive characteristics and well adapted to water bodies in south Vietnam.

This study presents results of the effects of dietary β-glucan (BG) on growth and survival of golden pompano, Trachinotus ovatus (mean weight ~6.5 g). An experiment was conducted with four treatments with β-glucan (0.0% (control), 0.05%, 0.1%, and 0.2%) supplemented in the diet. After 8 weeks of culture, the growth rate and final biomass were higher in the fish fed 0.1% BG supplemented, with significant difference among the control (P > 0.05). However, the survival rates ranked between 92 ÷ 95% with no significant difference among the treatments (P > 0.05). Coefficients of Variantion (CV) were between 24.1% in fish fed 0.05% BG to 36.9% in fish fed 0.2% BG (P < 0.05). In general, supplementation of 0.1% BG in the diet will boost growth, and final biomass of pompano fish.