Effects of recombinant Lactobacillus casei on growth performance, immune response and disease resistance in crucian carp, Carassius auratus.

In the present study, we constructed two recombinant Lactobacillus casei (L. casei) Lc-pPG-1-AcrV (surface-displayed) and Lc-pPG-2-AcrV (secretory) constitutively expressing AcrV protein of Aeromonas veronii (A. veronii). Expression of recombinant AcrV protein was verified by western blot and immunofluorescence technique. Compared with PBS group, the final weight (FW), weight gain (WG) and specific growth rate (SGR) of fish fed Lc-pPG-1-AcrV, Lc-pPG-2-AcrV and Lc-pPG diets after 56 days observed significantly increase (p < 0.05), while the feed conversion ratio (FCR) showed a significantly decrease (p < 0.05). The recombinant L. casei strains were orally administrated to crucian carp, and significant increased (p < 0.05) the immunoglobulin M (IgM), elevated the acid phosphatase (ACP), alkaline phosphatase (AKP), lysozyme (LZM) and superoxide dismutase (SOD) activity in serum. Moreover, leukocytes phagocytosis percentage and index of the recombinant L. casei were both enhanced. The results demonstrated that the recombinant L. casei could elicit systemic immune responses and increase the serum immunological index. The Interleukin-10 (IL-10), Interleukin-1ß (IL-1ß), interferon-γ (IFN-γ) and Tumor Necrosis Factor-α (TNF-α) levels in liver, spleen, kidney and intestine have up regulated significantly in tissues (p < 0.05), suggesting that the recombinant L. casei has the ability to induce expression of cytokines and enhance the innate immune response. Higher survival rates were exhibited that crucian carp immunized with Lc-pPG-1-AcrV (67.5%) and Lc-pPG-2-AcrV (52.5%) after challenge with A. veronii. In conclusion, these two recombinant L. casei vaccine were effective in improving crucian carp growth, immunity response and disease resistance. The recombinant L. casei strains may be a promising candidate for the development of an oral vaccine against A. veronii.

Oral Administration of Lactobacillus Casei Expressing Flagellin A Protein Confers Effective Protection against Aeromonas Veronii in Common Carp, Cyprinus Carpio.

Aeromonas veronii is a pathogen capable of infecting humans, livestock and aquatic animals, resulting in serious economic losses. In this study, two recombinant Lactobacillus casei expressing flagellin A (FlaA) of A. veronii, Lc-pPG-1-FlaA (surface-displayed) and Lc-pPG-2-FlaA (secretory) were constructed. The immune responses in fish administered with recombinant L. casei were evaluated. The two recombinant L. casei were orally administered to common carp, which stimulated high serum IgM and induced higher ACP, AKP, SOD and LYZ activity. Using qRT-PCR, the expression of IL-10, IL-8, IL-1ß, TNF-α and IFN-γ in the tissue of fish immunized with recombinant L. casei was significantly (p < 0.05) upregulated, which indicated that recombinant L. casei could activate the innate immune system to trigger the cell immune response and inflammatory response. Furthermore, recombinant L. casei was able to survive the intestinal environment and colonize in intestine mucosal. The study showed that after being challenged by A. veronii, fish administered with Lc-pPG-1-FlaA (70%) and Lc-pPG-2-FlaA (50%) had higher survival rates compared to Lc-pPG and PBS, indicating that recombinant L. casei might prevent A. veronii infection by activating the immune system to trigger immune responses. We demonstrated that flagellin as an antigen of vaccine, is acceptable for preventing A. veronii infection in fish. The recombinant L. casei expressing FlaA may be a novel mucosal vaccine for treating and controlling A. veronii.

Calycosin ameliorates diabetes-induced cognitive impairments in rats by reducing oxidative stress via the PI3K/Akt/GSK-3ß signaling pathway.

Diabetic encephalopathy is one of the most prevalent chronic complications of diabetes mellitus (DM), but there is currently no effective method of prevention nor proven therapeutic regimen for it. In this study, we investigated the effects of calycosin on cognitive behavior and the potential mechanism involved in streptozocin-induced diabetic rats. The effects of diabetes and calycosin treatment on spatial learning and memory were evaluated using the Morris Water Maze, passive avoidance and motor coordination tests. Histological analysis of the hippocampus cornu ammonis 1 (CA1) region was conducted in rats. The decreased expression of the synapsin (SYN) and postsynatptic density protein (PSD-95), as well as brain-derived neurotrophic factor (BDNF) in diabetic rats was measured by quantitative real-time PCR and western blot. Treatment with calycosin promoted a reduction in the expression of SYN, PSD-95 and BDNF. In addition, diabetic rats showed increased MDA levels, and decreased SOD levels and GSH-Px activities in the hippocampus, as well as increased AChE activity in the cerebral cortex; these changes were reversed by calycosin supplementation. Thus, the impairment of learning and memory in STZ-induced diabetic rats was alleviated by calycosin, and that the degree of alleviation was associated with oxidative stress. We also found that calycosin treatment significantly stimulated Akt phosphorylation and decreased GSK-3ß and tau phosphorylation, and that these changes could be restored by the PI3K/Akt inhibitor LY294002. In conclusion, calycosin had a beneficial effect on the amelioration, prevention and treatment of diabetes-associated cognitive deficits, through its involvement in oxidative stress, synaptic function and the PI3K/Akt/GSK-3ß pathway.

Antimicrobial and Antiviral Nanofibers Halt Co-Infection Spread via Nuclease-Mimicry and Photocatalysis.

The escalating spread of drug-resistant bacteria and viruses is a grave concern for global health. Nucleic acids dominate the drug-resistance and transmission of pathogenic microbes. Here, imidazolium-type poly(ionic liquid)/porphyrin (PIL-P) based electrospun nanofibrous membrane and its cerium (IV) ion complex (PIL-P-Ce) are developed. The obtained PIL-P-Ce membrane exhibits high and stable efficiency in eradicating various microorganisms (bacteria, fungi, and viruses) and decomposing microbial antibiotic resistance genes and viral nucleic acids under light. The nuclease-mimetic and photocatalytic mechanisms of the PIL-P-Ce are elucidated. Co-infection wound models in mice with methicillin-resistant S. aureus and hepatitis B virus demonstrate that PIL-P-Ce integrate the triple effects of cationic polymer, photocatalysis, and nuclease-mimetic activities. As revealed by proteomic analysis, PIL-P-Ce shows minimal phototoxicity to normal tissues. Hence, PIL-P-Ce has potential as a "green" wound dressing to curb the spread of drug-resistant bacteria and viruses in clinical settings.

A review on the exploitation of biodegradable magnesium-based composites for medical applications.

In recent years, materials science research based on magnesium (Mg) alloys has increased significantly due to their notable advantages over traditional metals. However, magnesium alloys are susceptible to excessive degradation and subsequent disruption of mechanical integrity; this phenomenon limits the utility of these materials. Mg alloys can thus be combined with other materials to form composites for medical applications. The present article describes key advances in and considerations for the development of biodegradable Mg-based composites (BMCs). The primary characteristics of these materials include their controllable degradation rates, tunable mechanical properties, adjustable structures to promote tissue repair, improved biocompatibility, and added functionality according to the purpose of the applications. Here we provide an overview of the current research on and development status of BMCs for biomedical materials, including the present limitations and challenges of their use. Finally, this paper comprehensively discusses the most promising directions of future development for these materials.