Sublingual immunization with Japanese encephalitis virus vaccine effectively induces immunity through both cellular and humoral immune responses in mice

The Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis. Although there are four classes of vaccines against JEV, all of them are administered by s.c or i.m injection. Here, the effectiveness of sublingual (s.l.) administration of a JEV live‐attenuated vaccine or recombinant modified vaccinia virus Ankara (MVA) vaccine, including JEV prM/E, was investigated. The mice were immunized three times i.m. or s.c. One week after the final immunization by both s.l. and i.m. routes, the titers of IgG1 induced by the recombinant MVA vaccine were higher than those induced by the live‐attenuated vaccine, whereas the titers of IgG2a induced by the live‐attenuated vaccine were higher than those induced by the recombinant MVA vaccine. However, both vaccines induced neutralizing antibodies when given by either s.l. or i.m. routes, indicating that both vaccines induce appropriate Th1 and Th2 cell responses through the s.l. and i.m. routes. Moreover, both vaccines protected against induction of proinflammatory cytokines and focal spleen white pulp hyperplasia after viral challenge. Virus‐specific IFN‐γ⁺ CD4⁺ and CD8⁺ T cells appeared to increase in mice immunized via both s.l. and i.m. routes. Interestingly, virus‐specific IL‐17⁺ CD4⁺ T cells increased significantly only in the mice immunized via the s.l. route; however, the increased IL‐17 did not affect pathogenicity after viral challenge. These results suggest that s.l. immunization may be as useful as i.m. injection for induction of protective immune responses against JEV by both live‐attenuated and recombinant MVA vaccines.     

An approach to bioassess pelagic ciliate biodiversity at different taxonomic resolutions in response to various habitats in the Amundsen Sea (Antarctica)

The rapid melting of glaciers and loss of sea ice will result in changes in habitat conditions that may drive substantial changes in biodiversity. In order to bioassess the changing polar ecosystem and evaluate biological conservation, pelagic ciliate communities at different taxonomic resolutions were studied at five habitats in the Amundsen Sea during the austral summer from December 2010 to January 2011. Distinctive spatial patterns were observed in the communities among the five habitats (oceanic areas, transitional areas, polynyas, edges of glaciers, and edges of sea ice) in response to environmental variability (e.g., temperature, salinity, chlorophyll a, and nutrients). The distributions in the numbers of different taxonomic levels and of three biodiversity indices (Shannon-Wiener H′, Pielou’s J′, and Margalef D) also revealed clear spatial variability with the maximum mean species number and indices in the polynya and maximum genus and family numbers in the transitional area. The presence/absence of data at taxonomic resolutions up to the family level provided sufficient information to evaluate the ecological patterns of pelagic ciliate communities and could accurately reflect habitat variations. The k-dominance curves illustrated clearly that maximum diversity was presented in the polynya at the species level and in the transitional area at the genus and family level. We suggest that the diversity at higher taxonomic resolutions should be considered more in future monitoring. Our findings provide basic data and an approach toward answering important questions about biological conservation, especially the biodiversity at various taxonomic resolutions in response to the increasing climate changes in polar ecosystems.     

Immobilization of glucose oxidase on graphene oxide for highly sensitive biosensors

Glucose oxidase (GOx) was immobilized onto graphene oxide (GRO) via three different preparation methods: enzyme adsorption (EA), enzyme adsorption and crosslinking (EAC), and enzyme adsorption, precipitation and crosslinking (EAPC). EAPC formulations, prepared via enzyme precipitation with 60% ammonium sulfate, showed 1,980 and 1,630 times higher activity per weight of GRO than those of EA and EAC formulations, respectively. After 59 days at room temperature, EAPC maintained 88% of initial activity, while EA and EAC retained 42 and 45% of their initial activities, respectively. These results indicate that the steps of precipitation and crosslinking in the EAPC formulation are critical to achieve high enzyme loading and stability of EAPC. EA, EAC and EAPC were used to prepare enzyme electrodes for use as glucose biosensors. Optimized EAPC electrode showed 93- and 25-fold higher sensitivity than EA and EAC, respectively. To further increase the sensitivity of EAPC electrode, multi-walled carbon nanotubes (MWCNTs) were mixed with EAPC for the preparation of enzyme electrode. Surprisingly, the EAPC electrode with additional 99.5 wt% MWCNTs showed 7,800-fold higher sensitivity than the EAPC electrode without MWCNT addition. Immobilization and stabilization of enzymes on GRO via the EAPC approach can be used for the development of highly sensitive biosensors as well as to achieve high enzyme loading and stability.     

Glycerol-fed microbial fuel cell with a co-culture of <Emphasis Type="Italic">Shewanella oneidensis</Emphasis> MR-1 and <Emphasis Type="Italic">Klebsiella pneumonae</Emphasis> J2B

Glycerol is an attractive feedstock for bioenergy and bioconversion processes but its use in microbial fuel cells (MFCs) for electrical energy recovery has not been investigated extensively. This study compared the glycerol uptake and electricity generation of a co-culture of Shewanella oneidensis MR-1 and Klebsiella pneumonia J2B in a MFC with that of a single species inoculated counterpart. Glycerol was metabolized successfully in the co-culture MFC (MFC-J&M) with simultaneous electricity production but it was not utilized in the MR-1 only MFC (MFC-M). A current density of 10 mA/m² was obtained while acidic byproducts (lactate and acetate) were consumed in the co-culture MFC, whereas they are accumulated in the J2B-only MFC (MFC-J). MR-1 was distributed mainly on the electrode in MFC-J&M, whereas most of the J2B was observed in the suspension in the MFC-J reactor, indicating that the co-culture of both strains provides an ecological driving force for glycerol utilization using the electrode as an electron acceptor. This suggests that a co-culture MFC can be applied to electrical energy recovery from glycerol, which was previously known as a refractory substrate in a bioelectrochemical system.