Aims:  To understand the modification of C4‐metabolism under anaerobic glycolysis condition by overexpressing anaplerotic enzymes, which mediating carboxylation of C3 into C4 metabolites, in Escherichia coli. Methods and Results:  Anaplerotic NADP‐dependent malic enzyme (MaeB), as well as the other anaplerotic enzymes, including phosphoenolpyruvate carboxylase (Ppc), phosphoenolpyruvate carboxykinase (Pck) and NAD‐dependent malic enzyme (MaeA), were artificially expressed and their C4 metabolism was compared in E. coli. Increasing MaeB expression enhanced the production of C4 metabolites by 2·4 times compared to the wild‐type strain in anaerobic glucose medium with bicarbonate supplementation. In MaeB expression, C4 metabolism by supplementing 10 g l−1 of NaHCO3 was three times than that by no supplementation, which showed the greatest response to increased CO2 availability among the tested anaplerotic enzyme expressions. Conclusions:  The higher C4 metabolism was achieved in E. coli expressing increased levels of the NADPH‐dependent MaeB. The greatest increase in the C4 metabolite ratio compared to the other tested enzymes were also found in E. coli with enhanced MaeB expression as CO2 availability increased. Significance and Impact of the Study:  The higher C4 metabolites and related biomolecule productions can be accomplished by MaeB overexpression in metabolically engineered E. coli.

There are two alternative pathways leading to methionine synthesis in microorganisms: The transsulfuration pathway involves cystathionine as the intermediate and utilizes cysteine as the sulfur source, but the direct sulfhydrylation pathway bypasses cystathionine and uses inorganic sulfur instead. While most microorganisms synthesize methionine via either one of these pathways, Corynebacterium glutamicum utilizes both pathways, which appear to be fully functional. In C. glutamicum, each pathway is catalyzed by independent enzymes and is tightly regulated by methionine. Although the physiological significance of parallel pathways remains to be elucidated, their presence suggests metabolic flexibility and efficient adaptation of the organism to its environment.

Although co-infection with multiple parasites is a frequent occurrence, changes in the humoral immune response against a pre-existing parasite induced as a result of a subsequent parasitic infection remain undetermined. Here, we utilized enzyme-linked immunosorbent assay (ELISA) to investigate antibody responses, cytokine production and enhanced resistance in Clonorchis sinensis-infected rats (Sprague-Dawley) upon Trichinella spiralis infection. Higher levels of C. sinensis-specific IgG and IgA were elicited upon T. spiralis infection, and these levels remained higher than in rats infected with C. sinensis alone. Upon subsequent infection with T. spiralis, IgG antibodies against C. sinensis appeared to be rapidly boosted at day 3, and IgA antibodies were boosted at day 7. Challenge infection of C. sinensis-infected rats with T. spiralis induced substantial mucosal IgG and IgA responses in the liver and intestine and increases in antibody-secreting plasma cells in the spleen and bone marrow. Subsequent infection also appeared to confer effective control of liver C. sinensis loads, resulting in enhanced resistance. Memory B cells generated in response to C. sinensis infection were rapidly amplified into antibody-secreting cells upon T. spiralis infection. These results indicate that enhanced C. sinensis clearance induced by co-infection is associated with systemic and mucosal IgG and IgA responses.

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A novel perturbing methodology using asymmetrical defected ground structure (DGS) is proposed for a circularly polarized Figure 10 Measured and simulated VSWR for the modified antenna design of Figure 7(b). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com](CP) annual ring antenna with improved antenna gain. By loading two fairs of half dumbbell-shaped DGS at four diagonal corners of the ring radiator, the orthogonally polarized modes are controlled. Simulated and measured results show that the proposed antenna demonstrates good CP radiations at the resonant frequency.