Antigenic and immunogenic properties of truncated VP28 protein of white spot syndrome virus in Procambarus clarkii

Previous studies identify VP28 envelope protein of white spot syndrome virus (WSSV) as its main antigenic protein. Although implicated in viral infectivity, its functional role remains unclear. In the current study, we described the production of polyclonal antibodies to recombinant truncated VP28 proteins including deleted N-terminal (rVP28ΔN), C-terminal (rVP28ΔC) and middle (rVP28ΔM). In antigenicity assays, antibodies developed from VP28 truncations lacking the N-terminal or middle regions showed significantly lowered neutralization of WSSV in crayfish, Procambarus clarkii. Further immunogenicity analysis showed reduced relative percent survival (RPS) in crayfish vaccinating with these truncations before challenge with WSSV. These results indicated that N-terminal (residues 1–27) and middle region (residues 35–95) were essential to maintain the neutralizing linear epitopes of VP28 and responsible in eliciting immune response. Thus, it is most likely that these regions are exposed on VP28, and will be useful for rational design of effective vaccines targeting VP28 of WSSV.     

Involvement of STIM1 and Orai1 in EGF-mediated cell growth in retinal pigment epithelial cells

Background

In non-excitable cells, one major route for calcium entry is through store-operated calcium (SOC) channels in the plasma membrane. These channels are activated by the emptying of intracellular Ca²⁺ store. STIM1 and Orai1 are major regulators of SOC channels. In this study, we explored the functions of STIM1 and Orai1 in epidermal growth factor (EGF)-induced cell proliferation and migration in retinal pigment epithelial cells (ARPE-19 cell line).

Results

EGF triggers cell proliferation and migration in ARPE-19 cells. Cell proliferation and migration involve STIM1 and Orai1, as well as phosphorylation of extracellular signal-regulated protein kinase (ERK) 1/2, and Akt. Pharmacological inhibitors of SOC channels and siRNA of Orai1 and STIM1 suppress cell proliferation and migration. Pre-treatment of mitogen-activated protein kinase kinase (MEK) inhibitors and a phosphatidylinositol 3 kinases (PI3K) inhibitor attenuated cell proliferation and migration. However, inhibition of the SOC channels failed to prevent EGF-mediated ERK 1/2 and Akt phosphorylation.

Conclusions

Our results showed that STIM1, Orai1, ERK 1/2, and Akt are key determinants of EGF-mediated cell growth in ARPE-19 cells. EGF is a potent growth molecule that has been linked to the development of PVR, and therefore, STIM1, Orai1, as well as the MEK/ERK 1/2 and PI3K/Akt pathways, might be potential therapeutic targets for drugs aimed at treating such disorders.     

Cloning and expression analysis of a CMS-related gene BcCoi1 from Brassica campestris ssp. chinensis

BcCoi1, a cytoplasmic male sterility related gene, which was isolated from flower buds of Brassica campestris ssp. chinensis Makino using the RACE technology, was characterized and submitted to the NCBI GenBank (accession no. GU263836). The gene encodes a 67.78-kD protein containing 16 leucine-rich repeats and an N-terminal F-box motif and is extremely similar to Arabidopsis thaliana Coi1 gene. The Southern blot showed that BcCoi1 belongs to a multigene family. In A. thaliana, the Coi1 gene is involved in jasmonate signaling, and Coi1 mutant displayed male sterility. In this study, qPCR results demonstrated that BcCoi1 was accumulated in stamens and was significantly higher expressed in flower organs of the maintainer line than in the CMS one. At the microsporocyte development stage, the gene was expressed at a significantly lower extent in the CMS line than in the maintainer line. This expression profile presumes that BcCoi1 plays a role in early microspore development in non-heading Chinese cabbage.     

Molecular cloning and characterization of ascorbate oxidase gene in non-heading Chinese cabbage

The cDNA clone of ascorbate oxidase gene was isolated from non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino, cv. Suzhouqing) and characterized. Sequence analysis showed that there was a high similarity between this sequence (named BcAO) and its homologues in other plant species. Southern blotting indicated that more than one nuclear gene encoded this enzyme in non-heading Chinese cabbage. The mRNA level of the BcAO gene in leaves was monitored by real-time PCR at different developmental stages and under different stress conditions. Results showed that the expression of BcAO was upregulated by light, and the BcAO gene responded to copper stress as well. After inoculation with Alternaria brassicae, the expression of BcAO in the leaves was increased in general and peaked at 12 and 72 h post inoculation, with much higher expression at the later date. Cloning the BcAO gene will enable us to further understand its function and would provide useful information for resistance breeding program for non-heading Chinese cabbage.     

Changes of Sleep Adaptation in Hospitalized Patients with Depression

Sleep adaptation in an unfamiliar environment, the so-called “first-night effect”, is known to occur in healthy individuals. To avoid the confounding effects of the “first-night effect”, the first-night sleep data are not used in most of sleep studies. In the present study, we examined changes of sleep adaptation in hospitalized patients with depression. Polysomnographic recordings were obtained for two consecutive nights from 14 patients, and sleep parameters were compared between both nights. Total sleep time, sleep latency, awakening times, movement awakening time, sleep efficiency, sleep architecture, rapid eye movement (REM) sleep latency, REM intensity, REM density, REM time, REM cycles, and other indicators showed no significant difference (p > 0.05) between the first and second nights. To conclude, hospitalized patients with depression have relatively less change in sleep adaptation, thus, the data from their first night do not need to be discarded.     

Surfactin-Induced Apoptosis Through ROS–ERS–Ca2+-ERK Pathways in HepG2 Cells

Although surfactin is able to inhibit cancer cell proliferation and to induce cancer cell apoptosis, the molecular mechanism responsible for this process remain elusive. In this study, the signaling network underlying the apoptosis of human hepatoma (HepG2) cells induced by surfactin was investigated. It is found that the reaction oxygen species (ROS) production and intracellular calcium ([Ca²⁺]_i) accumulation are both induced HepG2 cells apoptosis. The [Ca²⁺]_i exaltation was partly depended on the Ca²⁺ release from inositol 1,4,5-trisphosphate (IP3) and ryanodine (Ry) receptors channels, which both triggered endoplasmic reticulum stress (ERS). The results showed that surfactin induced the ROS production and ROS production led to ERS. The occurrence of ERS increased the [Ca²⁺]_i level and the processes associated with blocking extracellular signal-regulated kinase (ERK) pathway. According to a comprehensive review of all the evidence, it is concluded that surfactin induces apoptosis of HepG2 cells through a ROS–ERS–Ca²⁺ mediated ERK pathway.     

Construction of ploidy series of Saccharomyces cerevisiae by the plasmid YCplac33-GHK

An effective approach, using the plasmid YCplac33-GHK, is developed to construct a ploidy series of Saccharomyces cerevisiae. YCplac33-GHK harbors the HO gene under the control of galactose-inducible promoter and KanMX4 as the selective marker. The simple method can solve the problem of industrial applications of strains with resistance genes.     

Physiological mechanisms for plant distribution pattern: responses to flooding and drought in three wetland plants from Dongting Lake, China

Both flooding and drought are important in determining plant distribution in wetlands. However, the roles of plant’s physiological response to flooding and drought in accounting for plant distribution are far from clear. To this end, three typical wetland plants with different distribution patterns (high-elevation species Miscanthus sacchariflorus, low-elevation species Carex brevicuspis and Polygonum hydropiper) in Dongting Lake were treated with three water levels (flooding 25 cm, control 0 cm, drought ?25 cm), and relative growth rate (RGR), malondialdehyde (MDA) content, electrolyte leakage and proline content were investigated. The RGR of the three species decreased significantly in both flooding and drought treatments. Compared to the control, the RGR of M. sacchariflorus decreased more in the flooding treatment but less in the drought treatment compared to the other two species. The contents of MDA in the three species increased in both flooding and drought treatments, except for P. hydropiper in the flooding treatment. MDA contents increased more in M. sacchariflorus in the flooding treatment but less in the drought treatment compared to the other two species. Only M. sacchariflorus had a higher electrolyte leakage in the flooding treatment, and drought led to a higher electrolyte leakage in P. hydropiper and C. brevicuspis. Proline content increased 69.2, 66.7 and 39.6 % in P. hydropiper, C. brevicuspis and M. sacchariflorus in the flooding treatment, and increased 44.2, 13.0 and 45.3 % in the drought treatment, respectively. These results suggest that M. sacchariflorus has a higher tolerance to drought but a lower tolerance to flooding than do the other two species, which might be the intrinsic mechanisms accounting for their different distribution patterns.