Quadrivalent hemagglutinin and adhesion expressed on Saccharomyces cerevisiae induce protective immunity against Mycoplasma gallisepticum infection and improve gut microbiota.

Mycoplasma gallisepticum (MG) infection causes infectious respiratory diseases in poultry, causing economic losses to the poultry industry. Therefore, this study aims to develop a safe, convenient, and effective multivalent recombinant Saccharomyces cerevisiae vaccine candidate and to explore its potential for oral immunization as a subunit vaccine. Mycoplasma gallisepticum Cytadhesin (MGC) and variable lipoprotein and hemagglutinin (vlhA) are associated with the pathogenesis of MG. In this study, a quadrivalent recombinant Saccharomyces cerevisiae (ST1814G-MG) displaying on MGC2, MGC3, VLH5, and VLH3, proteins was innovatively constructed, and its protective efficiency was evaluated in birds. The results showed that oral immunization with ST1814G-MG stimulates specific antibodies in chickens, reshapes the composition of the gut microbiota, reduces the Mycoplasma loading and pulmonary disease injury in the lungs. In addition, we found that oral ST1814G-MG had better protection against MG infection than an inactivated vaccine, and co-administration with the inactivated vaccine was even more effective. The results suggest that ST1814G-MG is a potentially safer and effective agent for controlling MG infection.

De novo biosynthesis of anthocyanins in Saccharomyces cerevisiae using metabolic pathway synthases from blueberry.

BACKGROUND: Anthocyanins are water-soluble flavonoids in plants, which give plants bright colors and are widely used as food coloring agents, nutrients, and cosmetic additives. There are several limitations for traditional techniques of collecting anthocyanins from plant tissues, including species, origin, season, and technology. The benefits of using engineering microbial production of natural products include ease of use, controllability, and high efficiency. RESULTS: In this study, ten genes encoding enzymes involved in the anthocyanin biosynthetic pathway were successfully cloned from anthocyanin-rich plant materials blueberry fruit and purple round eggplant rind. The Yeast Fab Assembly technology was utilized to construct the transcriptional units of these genes under different promoters. The transcriptional units of PAL and C4H, 4CL and CHS were fused and inserted into Chr. XVI and IV of yeast strain JDY52 respectively using homologous recombination to gain Strain A. The fragments containing the transcriptional units of CHI and F3H, F3'H and DFR were inserted into Chr. III and XVI to gain Strain B1. Strain B2 has the transcriptional units of ANS and 3GT in Chr. IV. Several anthocyanidins, including cyanidin, peonidin, pelargonidin, petunidin, and malvidin, were detected by LC-MS/MS following the predicted outcomes of the de novo biosynthesis of anthocyanins in S. cerevisiae using a multi-strain co-culture technique. CONCLUSIONS: We propose a novel concept for advancing the heterologous de novo anthocyanin biosynthetic pathway, as well as fundamental information and a theoretical framework for the ensuing optimization of the microbial synthesis of anthocyanins.

Oral immunization of recombinant Saccharomyces cerevisiae expressing fiber-2 of fowl adenovirus serotype 4 induces protective immunity against homologous infection.

Hydropericardium-hepatitis syndrome (HHS) caused by fowl adenovirus (FAdV) serotype 4 strains is a highly contagious disease that causes significant economic loss to the global poultry industry. However, subunit vaccine against FAdV-4 infection is not yet commercially available to date. This study aims to explore the potential for oral immunization of recombinant Saccharomyces cerevisiae expressing Fiber-2 of FAdV-4 as a subunit vaccine. Here, we constructed recombinant S. cerevisiae (ST1814G/Fiber-2) expressing recombinant Fiber-2 (rFiber-2), which was displayed on the cell surface. To evaluate the immune response and protective effect of live recombinant S. cerevisiae, chickens were orally immunized with the constructed live ST1814G/Fiber-2, three times at 5-day intervals, and then challenged with FAdV-4. The results showed that oral administration of live ST1814G/Fiber-2 could stimulate the production of humoral immunity, enhance the body's antiviral activity and immune regulation ability, improve the composition of gut microbiota, provide protection against FAdV-4 challenge, reduce viral load in the liver, and alleviate the pathological damage of heart, liver, and spleen for chicken. In addition, we found the synergistic effect in combining the ST1814G/Fiber-2 yeast and inactivated vaccine to trigger stronger humoral immunity and mucosal immunity. Our results suggest that oral live ST1814G/Fiber-2 is a potentially safer auxiliary preparation strategy in controlling FAdV-4 infection.

Biodegradation of propyzamide by Comamonas testosteroni W1 and cloning of the propyzamide hydrolase gene camH.

Propyzamide is a widely used benzamide herbicide for controlling weeds in lettuce, soybeans, cotton and other crops. An efficient propyzamide-degrading strain W1 was firstly isolated from activated sludge and identified as Comamonas testosteroni. A metabolite of propyzamide by strain W1 was firstly identified. The novel gene camH encoding a hydrolase that catalyzed the amide bond cleavage of propyzamide was cloned from strain W1. The gene contained an open reading frame of 1452 bp, the deduced amino acid sequence showed low identity with other amidases. The recombinant enzyme CamH was expressed in Escherichia coli BL21 and purified. CamH displayed the highest activity at 30°C and pH 8.0 with propyzamide as the substrate. These results provide important knowledge on the fate of propyzamide in the biodegradation, and elucidate the biodegradation mechanism of propyzamide by the strain W1.