There are seven antigenically distinct serotypes of foot-and-mouth disease virus (FMDV), each of which has intratypic variants. In the present study, we have developed methods to efficiently generate promising vaccines against seven serotypes or subtypes. The capsid-encoding gene (P1) of the vaccine strain O1/Manisa/Turkey/69 was replaced with the amplified or synthetic genes from the O, A, Asia1, C, SAT1, SAT2, and SAT3 serotypes. Viruses of the seven serotype were rescued successfully. Each chimeric FMDV with a replacement of P1 showed serotype-specific antigenicity and varied in terms of pathogenesis in pigs and mice. Vaccination of pigs with an experimental trivalent vaccine containing the inactivated recombinants based on the main serotypes O, A, and Asia1 effectively protected them from virus challenge. This technology could be a potential strategy for a customized vaccine with challenge tools to protect against epizootic disease caused by specific serotypes or subtypes of FMDV.IMPORTANCE Foot-and-mouth disease (FMD) virus (FMDV) causes significant economic losses. For vaccine preparation, the selection of vaccine strains was complicated by high antigenic variation. In the present study, we suggested an effective strategy to rapidly prepare and evaluate mass-produced customized vaccines against epidemic strains. The P1 gene encoding the structural proteins of the well-known vaccine virus was replaced by the synthetic or amplified genes of viruses of seven representative serotypes. These chimeric viruses generally replicated readily in cell culture and had a particle size similar to that of the original vaccine strain. Their antigenicity mirrored that of the original serotype from which their P1 gene was derived. Animal infection experiments revealed that the recombinants varied in terms of pathogenicity. This strategy will be a useful tool for rapidly generating customized FMD vaccines or challenge viruses for all serotypes, especially for FMD-free countries, which have prohibited the import of FMDVs.

In an attempt to engineer a Yarrowia lipolytica strain to produce glycoproteins lacking the outer-chain mannose residues of N-linked oligosaccharides, we investigated the functions of the OCH1 gene encoding a putative ␣-1,6-mannosyltransferase in Y. lipolytica. The complementation of the Saccharomyces cerevisiae och1 mutation by the expression of YlOCH1 and the lack of in vitro ␣-1,6-mannosyltransferase activity in the Yloch1 null mutant indicated that YlOCH1 is a functional ortholog of S. cerevisiae OCH1. The oligosaccharides assembled on two secretory glycoproteins, the Trichoderma reesei endoglucanase I and the endogenous Y. lipolytica lipase, from the Yloch1 null mutant contained a single predominant species, the core oligosaccharide Man 8 GlcNAc 2 , whereas those from the wild-type strain consisted of oligosaccharides with heterogeneous sizes, Man 8 GlcNAc 2 to Man 12 GlcNAc 2 . Digestion with ␣-1,2-and ␣-1,6-mannosidase of the oligosaccharides from the wild-type and Yloch1 mutant strains strongly supported the possibility that the Yloch1 mutant strain has a defect in adding the first ␣-1,6-linked mannose to the core oligosaccharide. Taken together, these results indicate that YlOCH1 plays a key role in the outer-chain mannosylation of N-linked oligosaccharides in Y. lipolytica. Therefore, the Yloch1 mutant strain can be used as a host to produce glycoproteins lacking the outer-chain mannoses and further developed for the production of therapeutic glycoproteins containing human-compatible oligosaccharides.Yeast can secrete a variety of proteins in much the same way that mammalian cells do. The presence of yeast-specific outerchain mannosylation, however, has been a primary hindrance to the exploitation of yeast for therapeutic glycoprotein production, because glycoproteins decorated with yeast-specific glycans are immunogenic and show poor pharmacokinetic properties in humans (1, 24). In the budding yeast Saccharomyces cerevisiae, the N-linked oligosaccharides assembled on glycoproteins include hypermannose structures with outer chains that may contain up to 200 mannose units (6). Elongation of the outer chain is initiated by the Och1 protein, which adds the first ␣-1,6-linked mannose to the core N-linked oligosaccharides upon their arrival in the Golgi apparatus in S. cerevisiae (17). Following the addition of the first ␣-1,6-mannose by Och1p, the core oligosaccharide is elongated by additional ␣-1,6-mannosyltransferases, Mnn9p and Van1p, which extend the ␣-1,6-linked polymannose backbone, and the core oligosaccharide is further branched by the addition of ␣-1,2-and ␣-1,3-linked mannoses (5, 8). Other yeast species, including Pichia pastoris, Hansenula polymorpha, and Schizosaccharomyces pombe, also use the Och1 protein to extend the mannose outer chain of N-glycans (14, 24, 26, 28). Therefore, the elimination of the Och1 protein was performed to block the yeast-specific outer-chain mannosylation, followed by further engineering of yeast N-glycosylation pathways for the production of glycoproteins with hum...

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The genomewide gene expression profiling of the methylotrophic yeast Hansenula polymorpha exposed to cadmium (Cd) allowed us to identify novel genes responsive to Cd treatment. To select genes whose promoters can be useful for construction of a cellular Cd biosensor, we further analyzed a set of H. polymorpha genes that exhibited >6-fold induction upon treatment with 300 M Cd for 2 h. The putative promoters, about 1,000-bp upstream fragments, of these genes were fused with the yeast-enhanced green fluorescence protein (GFP) gene. The resultant reporter cassettes were introduced into H. polymorpha to evaluate promoter strength and specificity. The promoter derived from the H. polymorpha SEO1 gene (HpSEO1) was shown to drive most strongly the expression of GFP upon Cd treatment among the tested promoters. The Cd-inducible activity was retained in the 500-bp deletion fragment of the HpSEO1 promoter but was abolished in the further truncated 250-bp fragment. The 500-bp HpSEO1 promoter directed specific expression of GFP upon exposure to Cd in a dose-dependent manner, with Cd detection ranging from 1 to 900 M. Comparative analysis of the Saccharomyces cerevisiae SEO1 (ScSEO1) promoter revealed that the ScSEO1 promoter has a broader specificity for heavy metals and is responsive to arsenic and mercury in addition to Cd. Our data demonstrate the potential use of the HpSEO1 promoter as a bioelement in whole-cell biosensors to monitor heavy metal contamination, particularly Cd.Industrial activities lead to large-scale environmental contamination with toxic heavy metals, such as cadmium (Cd) and mercury (Hg). These metals are toxic even at low levels and tend to accumulate in the body over an extended period of time, which can eventually cause serious health problems in humans. Therefore, the development of monitoring systems for these metal ions in the environment has become increasingly important in order to prevent chronic exposure to these pollutants (2). As a response to this need, numerous biological systems and nonbiological sensors based on the emerging nanotechnology have been developed to monitor heavy metal contamination (38, 43). In particular, biosensors that use unicellular microorganisms as analytical tools to monitor heavy metals have drawn attention because of several practical advantages (1): the large population size, rapid growth rate, low cost, and easy maintenance. Moreover, the feasibility of genetic manipulation makes microbial cells an attractive choice as environmental bioreporters.Many current microbial whole-cell sensors are based on genetically modified microorganisms (43,28). In general, microbial biosensors comprise the molecular fusion of two linked genetic elements: a sensing bioelement and a reporter gene. In most cases, the sensing element is a promoter that specifically responds to the presence or absence of the target molecule, and the reporter gene, which is fused to the sensing element, encodes a quantifiable molecule such as a bioluminescent or fluorescent protein (13). In creating ...