Organogel nanoemulsion containing Nisin and D-limonene and its antimicrobial activity

The aim of this study was to investigate a novel delivery system containing D-limonene and nisin by food organogel-nanoemulsion and study its effect on the antimicrobial activity. Organogel-nanoemulsion containing with D-limonene and nisin or without nisin was prepared by a homogenization method. Factors that may affect the droplet size and stability of organogel-nanoemulsion such as pressure and surfactant to oil ratio were studied. The average droplet size decreased with pressure, and the organogel-nanoemulsion could achieve good stability at low surfactant to oil ratio. Positive effects and outstanding antimicrobial activities of organogel-nanoemulsion containing with D-limonene and nisin were confirmed by MICs comparison, growth curves of bacteria, scanning electron microscopy and determination of cell constituents’ release. Furthermore, the organogel-nanoemulsion applied as food preservative in milk also shown excellent antimicrobial performance. Overall, the research described in the current article show that organogel-nanoemulsion containing with D-limonene and nisin may be an effective antimicrobial system for the production and preservation of food

Isolation and functional characterization of bidirectional promoters in rice

Bidirectional promoters, which show great application potential in genetic improvement of plants, have aroused great research interest recently. However, most bidirectional promoters were cloned individually in the studies of single genes. Here, we initiatively combined RNA-seq data and cDNA microarray data to discover the potential bidirectional promoters in rice genome. Based on the expression level and correlation of each adjacent and oppositely transcribed gene pair, we selected four candidate gene pairs. Then, the intergenic region between each pair was isolated and cloned into a dual reporter vector pDX2181 for functional identification. GUS and GFP assays of the transgenic plants indicated that all the intergenic regions showed bidirectional expression activity in various tissues. Through 5’ and 3’ deletion analysis on one of the above bidirectional promoters, we identified the enhancing region which sharply increased its bidirectional expression efficiency and the essential regions respectively responsible for its 5’ and 3’ basic expression activity. The bidirectional arrangement of the four gene pairs in six gramineous plants was also analyzed, showing the conserved characteristics of the four bidirectional promoters identified in our study. In addition, two novel cis-sequences conserved in the four bidirectional promoters were discovered by bioinformatic identification. Our study proposes a feasible method for selecting, cloning and functionally identifying bidirectional promoters as well as for discovering their bidirectional regulatory regions and conserved sequences in rice

Listeria ivanovii infection in mice: restricted to the liver and lung with limited replication in the spleen

Listeria monocytogenes (LM) vectors have shown much promise in delivery of viral and tumor antigens for the development of vaccines. Listeria ivanovii (LI) is a closely related bacterium with a similar intracellular life cycle that may offer advantages over LM because it is not a human pathogen, but can infect other animal species. Recent studies show that recombinant LI expressing M. tuberculosis antigens is effective in inducing protective immunity in mouse models, demonstrating the potential of LI as a live vaccine vector. However, a key barrier in the development of LI into a live vaccine vector is that its pathogenic and immunogenic characteristics have yet to be fully understood. Therefore, in this research, C57BL/6J mice were inoculated with LM or LI intravenously or intranasally, and bacterial loads, histopathologic changes, and cytokine production were determined at indicated days post inoculation. Results showed that after intravenous infection with LM or LI, bacteria were found proliferating in the liver, spleen and lung. However, LI could only reach a heavy burden in the liver and its ability to multiply and to resist host immunity seemed limited in the spleen and lung. After intranasal inoculation with LI, bacteria were mainly localized in the lung and failed to infect liver or spleen, while LM could. In organs with heavy LI burden, lesions were isolated, localized and densely packed, compared to lesions caused by LM, which were invasive. In the liver of intravenously inoculated mice and lung of intranasally inoculate mice, LI was able to elicit comparable cytokine production with LM and cause less severe histopathologic damages, and thus could be considered as a vector for treating or preventing hepatic or pulmonary diseases

MeioBase: a comprehensive database for meiosis

Meiosis is a special type of cell division process necessary for the sexual reproduction of all eukaryotes. The ever expanding meiosis research calls for an effective and specialized database that is not readily available yet. To fill this gap, we have developed a knowledge database MeioBase (http://meiosis.ibcas.ac.cn), which is comprised of two core parts, Resources and Tools. In the Resources part, a wealth of meiosis data collected by curation and manual review from published literatures and biological databases are integrated and organized into various sections, such as Cytology, Pathway, Species, Interaction, and Expression. In the Tools part, some commonly used tools have been integrated into MeioBase, such as Search, Download, Blast, Comparison, My Favorites, Submission, and Advice. With a simplified and efficient web interface, users are able to search against the database with gene model IDs or keywords, and batch download the data for local investigation. We believe that MeioBase can greatly facilitate the researches related to meiosis

Exopolysaccharides play a role in the swarming of the benthic bacterium Pseudoalteromonas sp. SM9913

Most marine bacteria secrete exopolysaccharide (EPS), which is important for bacterial survival in the marine environment. However, it is still unclear whether the self-secreted EPS is involved in marine bacterial motility. Here we studied the role of EPS in the lateral flagella-driven swarming motility of benthic bacterium Pseudoalteromonas sp. SM9913 (SM9913) by a comparison of wild SM9913 and ΔepsT, an EPS synthesis defective mutant. Reduction of EPS production in ΔepsT did not affect the growth rate or the swimming motility, but significantly decreased the swarming motility on a swarming plate, suggesting that the EPS may play a role in SM9913 swarming. However, the expression and assembly of lateral flagella in ΔepsT were not affected. Instead, ΔepsT had a different swarming behavior from wild SM9913. The swarming of ΔepsT did not have an obvious rapid swarming period, and its rate became much lower than that of wild SM9913 after 35 h incubation. An addition of surfactin or SM9913 EPS on the surface of the swarming plate could rescue the swarming level. These results indicate that the self-secreted EPS is required for the swarming of SM9913. This study widens our understanding of the function of the EPS of benthic bacteria

LPAIV H9N2 drives the differential expression of goose interferons and proinflammatory cytokines in both in vitro and in vivo studies

Geese, as aquatic birds, are an important natural reservoir of avian influenza virus (AIV). To characterize the innate antiviral immune response against AIV H9N2 strain infection in geese as well as the probable relationship between the expression of immune-related genes and the distribution of viral antigens, we investigated the levels of immune-related gene transcription both in AIV H9N2 strain-infected geese and in vitro. The patterns of viral location and the tissue distribution of CD4- and CD8α-positive cells were concurrently detected by immunohistochemical staining, which revealed respiratory and digestive organs as the primary sites of antigen-positive signals. Average AIV H9N2 viral loads were detected in the faeces, Harderian gland and trachea, where higher copy numbers were detected compared with the rectum. Our results suggested the strong induction of proinflammatory cytokine expression compared with interferons (IFNs). Notably, in most tissues from the AIV H9N2 strain-infected birds, IFNα and IFNγ gene transcripts were differentially expressed. However, inverse changes in IFNα and IFNγ expression after AIV H9N2 strain infection were observed in vitro. Taken together, the results suggest that AIV H9N2 is widely distributed in multiple tissues, efficiently induces inflammatory cytokines in the Harderian gland and spleen of goslings and inversely influences type I and II IFN expression both in vivo and in vitro. The findings of this study further our understanding of host defence mechanisms and the pathogenesis of the H9N2 influenza virus in geese