Search

Members of the E74-like factor (ELF) subfamily are involved in the immune stress process of organisms by regulating immune responses and the development of immune-related cells. PmE74 of Penaeus monodon was characterized and functionally analyzed in this study. The full length of PmE74 was 3106 bp, with a 5'-UTR of 297 bp, and a 3'-UTR of 460 bp. The ORF (Open reading frame) was 2349 bp and encoded 782 amino acids. Domain analysis showed that PmE74 contains a typical Ets domain. Multiple sequence alignment and phylogenetic tree analysis showed that PmE74 clustered with Litopenaeus vannamei E74 and displayed significant similarity (98.98%). PmE74 was expressed in all tissues tested in P. monodon, with the highest levels of expression observed in the testis, intestine, and epidermis. Different pathogen stimulation studies have revealed that PmE74 expression varies in response to different pathogen stimuli. A 96-h acute low salt stress study revealed that PmE74 in the hepatopancreas was upregulated and downregulated in the salinity 17 group and considerably downregulated in the salinity 3 group, whereas PmE74 in gill tissue was considerably downregulated in both groups. Further, by knocking down PmE74 and learning the trends of its linkage genes PmAQP1, PmNKA, PmE75, PmFtz-f1, PmEcR, and PmRXR in response to low salt stress, it was further indicated that PmE74 could have a vital role in the regulation of low salt stress. The SNP test revealed that PmE74-In1-53 was significantly associated with low salt tolerance traits in P. monodon (P 0.05). The findings of this study can aid in the advancement of molecular marker-assisted breeding in P. monodon, as well as provide fundamental data and methodologies for further investigation of its low salt tolerance strains in P. monodon.

As a highly conserved transcription factor family, DMRTs (Doublesex and Mab-3-related transcription factors) are involved in sex determination and sexual differentiation in numerous animals. In the present study, we identified a DM (Doublesex/Mab-3)-domain gene in Penaeus monodon, which we named PmDMRT11E because it shared many similarities with DMRT11E homologs and has a close relationship in the phylogeny of different species. The three-dimensional structure and amino acid alignments indicated the stability and conservation of the DM domain. Real-time PCR analysis revealed that PmDMRT11E was highly and preferentially expressed in the testis of sub-adult shrimp. During embryogenesis, the expression level of PmDMRT11E was higher at the nauplius than at other periods. PmDMRT11E dsRNA injection significantly decreased the transcription factor Sox9 and increased ovarian marker Foxl2 expression, implying its important regulatory role in the mechanism of male determination. Moreover, dsDMRT11E caused abnormal sperm development, indicating that PmDMRT11E may be closely related to gonadal development and spermatogenesis.

The increased application of chemical fertilizers in citrus orchards and the non-point source nitrogen (N) and phosphorus (P) diffusion threaten the fresh water quality of the Three Gorges Reservoir area of China. A 10-year field trial on sloping citrus lands was conducted to evaluate five protection methods for reducing N and P losses: 1) intercropping with perennial white clover (CW); 2) straw mulching of the soil surface (CS); 3) intercropping with yellow daylily contour hedgerows (CH); 4) an impermeable membrane buried in the soil along the contour lines (CM); and 5) intercropping with a rotation of wheat and peanut (CWP). An area of conventional citrus management was also maintained as the control (CK). The results showed that CM and CH were the most effective methods for reducing surface runoff. The sediment yield were reduced at the highest rate by CW and CH and was also significantly reduced by CS. Reduced runoff volume and sediment yield were the crucial mechanism for the reductions in N and P losses. Compared with the control, CW, CS, CH, and CM reduced annual runoff by 9%, 13%, 25%, and 30%, sediment yield by 77%, 55%, 71%, and 28%, N loss by 10%, 23% 36%, and 37%, and P loss by 39%, 31%, 27%, and 25%, respectively. CW, CS, CH, and CM were effective in reducing N and P losses from the sloping citrus land. However, over the long-term, surface soil nutrient accumulation in CW, CS, and CH diminished the benefit of those methods in reducing N and P losses. In addition, CWP increased soil erosion and nutrient loss, which showed that citrus intercropping with other crops was an unsuitable method for citrus sloping land in the Three Gorges area.

In this study, 45# carbon steels were boronized, borosulphurized and RE-borosulphurized at 950 °C for 6 h, respectively. The samples were then characterized by scanning electron microscopy, X-ray diffraction, Auger electron spectroscopy, microhardness tester and ring-on-block wear tester. It has shown that the diffusion front (the interface between the diffusion layer and the substrate) of the boride layer (BL) and the boro-sulfide layer (BSL) is saw tooth shape, while the diffusion front of the RE-boro-sulfide layer (RBSL) is flat. Compared with BSL layer, RBSL layer has a smaller and more uniform grain size, and a flatter hardness gradient from the surface to the diffusion front. The RBSL layer, consisting of an outer layer (from surface to 30 μm) mainly composed of Fe-B and an inner layer (from 30 μm to the diffusion front) mainly composed of Fe-S, has the best wear resistance and the most sufficient adhesion among those three.

A long-term experiment set up in 1980 compared the effects of applying manures and chemical fertilizers on a paddy soil in the Taihu Lake region, China. Of the fourteen randomly distributed treatments consisting of different combinations of organic manure, inorganic nitrogen (N), phosphorus (P), and potassium (K), and rice straw, eight were selected for the present study in 2007. Application of organic manure plus straw significantly increased soil organic carbon (SOC) content of the topsoil (0-10 cm) compared to that of chemical fertilizers alone. The content of SOC was relatively stable in the 10-30 cm layer in the chemical fertilizer treatments and in the 20-40 cm layer in the manure treatments. The stable carbon isotope ratio (δ 13 C ) ranged from −24% to −28% and increased gradually with depth. The content of SOC was significantly ( P 0.05) negatively correlated with d 13 C. In the 0-20 cm layer, the d 13 C value significantly decreased in the treatments of manure alone (M), manure and chemical N and P fertilizers (MNP), manure and chemical N, P, and K fertilizers (MNPK), manure, rice straw, and chemical N fertilizer (MRN), and chemical N fertilizer and rice straw (CNR), as compared with the no-fertilizer control. In the 30-50 cm layer, however, the ratio significantly increased in all the treatments except Treatment CNR. Mineralization of organic C peaked in the first 2-4 d of incubation and gradually leveled off thereafter over the first 3 weeks, being faster in the manure treatments than the chemical fertilizer treatments. The average rate of mineralization varied from 55.36 to 75.46 mL CO 2 kg −1 d −1 and that of stable mineralization from 10 to 20 mL CO 2 kg −1 d −1 . In eight weeks of incubation, cumulative mineralization was always higher in the manure treatments than the chemical fertilizer treatments, being the highest in Treatment MRN. Combined humus in the soil was mainly (over 50%) composed of tightly combined fraction. The loosely combined humus and its ratio of humic acid (HA) to fulvic acid (FA) significantly increased with long-term application of organic manure and chemical fertilizers. It could be concluded that the cycle of organic C in the paddy soil ecosystem studied was stable over the long-term application of fertilizers and continued cultivation.

Cobalt content, grain size, microhardness and tensile strength of nanocrystalline Ni–Co deposits produced from a solution containing saccharin and cobalt sulfate at constant electrodeposition conditions (pulse on-time Ton at 1 ms and pulse off-time Toff at 15 ms) but varying the peak current density Jp were investigated. It is found that an increase in Jp makes the deposit Co content lower, colony-like morphology more obvious, grain size smaller, and hardness and tensile strength higher. All of the facts are believed to result from the higher overpotential and nucleation rates caused by the Jp increase. But its further increase could lead to reduction in the hardness and tensile strength. Peak current densities in the range of 100–120 A dm−2 are recommended for the preparation of nanostructured Ni–Co alloy deposits with grain sizes in the range of 15–20 nm, containing 7–8% Co, possessing hardness of 590–600 kg mm−2 and tensile strength of 1180–1200 MPa—significantly higher than the strength of pure nickel deposit which is produced by the similar method and gets similar grain size.