Transcriptome analysis endoplasmic reticulum-stress response in Litopenaeus vannamei hemocytes.

Numerous studies have proved that endoplasmic reticulum (ER)-stress is an important cause of aquatic animal diseases. Therefore, for effectively preventing and controlling aquatic animal diseases, a systematic and in-depth understanding of the environmental stress response in aquatic animals is necessary. In present study, the influence of ER-stress in Litopenaeus vannamei was investigated using Illumina HiSeq based RNA-Seq. Comparing to the cDNA library of hemocytes treated with DMSO in L. vannamei, 286 unigenes were significantly upregulated and 473 unigenes were significantly down-regulated in the Thapsigargin treated group. KEGG analysis indicated that the differentially expressed genes (DEGs) are mainly related to ER-stress, immune as well as metabolism. Besides the classical ER-stress response pathways, the regulation of cell cycle and DNA replication are also important measures of ER-stress response. It has been suggested that the influence of ER-stress on immune genes might be an important factor in environmental stress inducing shrimp disease. Our investigation exhibited that immune-related DEG Prophenoloxidase activating enzyme 2 (LvPPAE2) roled in anti-pathogen immunity of shrimp. This study provides a solid foundation for uncovering the environmental adaptation response and especially its relationship with L. vannamei immune system.

A IFI27 gene contributes to ER-stress mediated apoptosis and benefits for white spot syndrome virus infection in Litopenaeus vannamei.

The interplay between virus and host has been one of the hot spot in virology, and it is also the important aspect of revealing the mechanism of virus infection. Increasing studies revealed that several key molecules took part in the process of virus-host interaction. White spot syndrome virus (WSSV) has been proved to affect several physiological processes of the host cells, especially apoptosis. While the relationship between them still remains unclear. In this study, a IFI27 gene (LvIFI27) of Litopenaeus vannamei was cloned. It is indicated that LvIFI27 was induced upon endoplasmic reticulum (ER)-stress and unfolded protein response activator Thapsigargin. Unlike human IFI27 locating to mitochondria, LvIFI27 lied to ER, and was involved in cell apoptosis process. Moreover, results of cumulative mortality analysis showed that LvIFI27 might contributed to WSSV proliferation by promoting apoptosis during the process of viral infection. Findings in this study enriched our understanding of the relationship between WSSV infection and ER-stress mediated apoptosis.

Transcriptome analysis of the influence of high plant protein based diet on Trachinotus ovatus liver.

Seeking out fish meal (FM) alternatives is an important requirement for aquaculture all over the world. And most practitioners believe that the plant protein is most potential for FM surrenal. While high plant protein feed caused some common problems in aquatic livestock: the absorption rate and growth rate are decreased, and even caused digestive tract inflammation. In present study, the inflence of high plant protien feed in Trachinotus ovatus was investigated using illumina HiSeqTM2000 based RNA-Seq. By comparing the two groups of cDNA libraries developed from high plant protien based diet or FM based diet fed T. ovatus livers, 836 unigenes were significantly upregulated, and 345 were significantly down regulated. KEGG analysis indicated that the differentially expressed genes (DEGs) are mainly metabolic-related genes. It was found that more than 28 DGEs beloned to the protein metabolism and absorption, lipid biosynthesis or other metabolic pathways. It indicated that high plant protein based diet had broad effects on metabolism on T. ovatus. There were also more DEGs belong to immune-related signaling pathways, include genes were involved in pathpathogen resistance and genes related to immunity system. These DEGs provided useful clues to explore the mechanisms that high plant protein based diet caused side effects on T. ovatus. These results improved our current understanding of the response of high plant protein based diet in T. ovatus, and outstanding the reasons of the side effect caused by high protein based diet.

Litopenaeus vannamei Sma and Mad related protein 5 gene is involved in stress response and white spot syndrome virus infection.

Cell survival is based on the stability of intracellular state. It was well known that biochemical reactions in cells require specific intracellular environments, such as pH and calcium concentration. While the mechanism of stabilizing the intracellular environment is complex and far from clear. In this study, a Sma and Mad related protein 5 gene (LvSmad5) of Litopenaeus vannamei was cloned. LvSmad5 was located to both cytoplasm and nucleus. And subcellular localization of LvSmad5 was responsed to the changing of cells internal and external environment. Besides, it was found that subcellular localization of LvSmad5 was also regulated by unfolded protein response. Moreover, it was proved that nucleic localization of LvSmad5 could significantly increase the white spot syndrome virus (WSSV) infection in shrimp, and knockdown expression of LvSmad5 decreased the cumulative mortality of WSSV infection shrimp. Further investigation revealed that cytoplasm LvSmad5 could interplay with shrimp hexokinase 1, and contribute to glycolysis. These results indicated that LvSmad5 played a role in L. vannamei environmental stress response, and was used by WSSV for its replication.

Identification and functional characterization of a systemic RNA interference defective 1 gene in Litopenaeus vannamei.

RNA interference (RNAi) is a conservative and important functional pathway in eukaryocyte. It regulates the expression of genes that are engaged in a variety of cellular physiological functions. Among the functions of RNAi, its antiviral function have attracted many attentions.The RNAi pathway molecules are able to recognize virus-related dsRNA and degrade it, therefore killing the virus. More importantly, RNAi could mediate systemic antiviral responses, transmit from cell to cell, and systemic RNA interference defective 1 (SID1) was thought to play an important role in this process. In the present study, a SID1 gene (LvSID1) of Litopenaeus vannamei was cloned. LvSID1 could locate to both plasma membrane and endoplasmic reticulum. Result of real-time RT-PCR assay showed that it was highly expressed in shrimp gills. Besides, it was shown that over-expressed LvSID1 in Sf9 cells could significant enchane RNAi efficiency. It was found that the expression of LvSID1was regulated by white spot syndrome virus (WSSV), and knockdown expression of LvSID1 increased the cumulative mortality of WSSV infection shrimp. These results suggested that LvSID1 likely to played a role in L. vannamei systemic RNAi, and was involved in WSSV resistence.

A Litopenaeus vannamei TRIM32 gene is involved in oxidative stress response and innate immunity.

Tripartite motif (TRIM) family proteins are named by the presence of tripartite motifs in their amino terminal domains. Apart from the amino terminal, their carboxyl terminal contain variable domains which mediate diverse functions of the TRIM proteins. It had been found that TRIM proteins played important roles in distinct biological processes, such as innate immunity, anti-tumor immunity, cell cycle regulation and so on. In the present study, we cloned a TRIM32 (LvTRIM32) gene from Litopenaeus vannamei. LvTRIM32 was highly expressed in hemocytes, gills and epidermis, and subcellular localization analysis indicated that it was widely distributed in S2 cells. In vitro ubiquitination assays indicated that LvTRIM32 had E3 ubiquitin ligase activity. Results of real-time RT-PCR assay showed that LvTRIM32 was induced in shrimp hemocytes upon oxidative stress. It was also proved that the promoter activity of LvTRIM32 was enhanced by NF-E2-related factor, and knocked-down expression of LvTRIM32 depressed the expression of malic enzyme and epoxide hydrolase. Downregulated LvTRIM32 suppressed the cumulative mortality of shrimp under oxidative stress. Moreover, it was found that LvTRIM32 could be induced in shrimp hemocytes upon immunostimulation, and downregulated LvTRIM32 increased the cumulative mortality of shrimp infected with white spot syndrome virus (WSSV) or Vibrio alginolyticus. Collecting results suggested that LvTRIM32 was a member of shrimp antioxidant stress system, and it was also involved in WSSV- or V. alginolyticus-infection resistance.

Identification and functional characterization of a C-type lectin gene from Litopenaeus vannamei that is associated with ER-stress response.

C-type lectins (CTLs), which bind carbohydrates in a Ca2+-dependent manner, are involved in many cellular activities, especially immunity. CTLs play important roles in both the antibacterial and the antiviral immune response and are also associated with autoimmunity. Several CTLs have been investigated in crustaceans, primarily with respect to their function in the immune response. In this study, we cloned a novel CTL gene (LvCTLU) from Litopenaeus vannamei. LvCTLU is involved in microbe agglutination and phagocytosis. Downregulating LvCTLU increased the cumulative mortality of L. vannamei after Vibrio parahemolyticus infection. Similar to other reported CTLs, LvCTLU also had antiviral properties. Downregulation of LvCTLU also increased the cumulative mortality of L. vannamei after infection with white spot syndrome virus. More importantly, LvCTLU expression was induced by the unfolded protein response (UPR), which is the key pathway in the endoplasmic reticulum (ER)-stress response of eukaryotic organism. Our results suggested that this protein might be involved in the shrimp ER-stress response. Reporter gene assay indicated that LvCTLU was regulated by X-box-binding protein 1, which is the key transcription factor in the UPR. Our study thus revealed that LvCTLU plays vital roles in both the anti-pathogen immune response and the ER-stress response.

Resonantly pumped high power flat L-band erbium-doped superfluorescent fiber source.

An all-single-mode-fiber L-band superfluorescent fiber source (SFS) with 1 W output power, 34.3 nm bandwidth (FWHM) and 54% optical conversion efficiency is constructed by seeding a high power erbium-doped fiber amplifier (EDFA) with a low power L-band ASE seed source to avoid parasitic lasing. The source is resonantly pumped by a high power C-band SFS peaked at 1545 nm.

Watt-level L band superfluorescent fiber source.

An L band superfluorescent fiber source (SFS) with output power of 0.94W is presented, under 4.4W 976nm pump power. The optical conversion efficiency is about 21%. The spectrum covers the broad wavelength range from 1560nm to 1615nm. The high power L band SFS is constructed by a low power L band amplified spontaneous emission (ASE) seed source and a high power erbium-ytterbium co-doped fiber (EYDF) amplifier in double pass forward pumping configuration.

Branch arm filtered coherent combining of tunable fiber lasers.

A branch arm filtering technique is firstly proposed and experimentally demonstrated. A tunable band pass filter is inserted into one branch arm of the Mach-Zehnder type resonator instead of into the common arm as usual, in the coherent combining of two tunable fiber lasers. The arrangement improves the efficiency of the laser without obvious spectral quality penalty. The laser can be tuned from 1530 nm to 1570 nm with little power fluctuation, which is limited by the tuning range of the filter. A novel scaling scheme is also proposed, allowing the technique to be applied to the tuning of an extremely high power laser with a low power filter. The technique is expected to be compatible with other kinds of lasers such as linearly polarized lasers, Michelson type resonator and bulk lasers as well.

Tunable high-peak-power, high-energy hybrid Q-switched double-clad fiber laser.

A cw laser-diode-pumped Yb-doped double-clad fiber laser operating in a hybrid Q-switched regime was demonstrated. The output pulses had a duration as short as 4.2 ns, a tunable wavelength range from 1080.8 to 1142.7 nm, and a linewidth of less than 0.05 nm. Maximum peak power of approximately 175 kW and single-pulse energy of 1.57 mJ were obtained.

Narrow-linewidth widely tunable hybrid Q-switched double-clad fiber laser.

A laser-diode-pumped Yb-doped double-clad fiber laser operating in a hybrid Q-switched regime has been demonstrated. With pulsed pump light and stimulated Brillouin scattering of the gain fiber as the Q-switching mechanisms, the laser generated nanosecond pulses with a stable repetition rate. A single-pulse energy of as much as 143.1 microJ with a peak power of 28.6 kW was obtained. Use of an external-cavity diffraction grating in the Littman configuration permitted tuning of the laser wavelength over a 15.7-THz range from 1080 to 1140 nm, and a linewidth of 0.04 nm over the whole tuning range was achieved.