Search

Viral diseases are a serious issue for the shrimp aquaculture industry. White spot syndrome virus (WSSV) has been considered one of the most dangerous pathogens infecting cultured shrimp, causing a mortality rate as high as 100% within 7–10 days of viral infection. So far, several protocols have been applied to protect shrimp against virus attacks, but their protection efficiency is very limited. In this study, for the first time, three melanin-containing feedstuffs (F1, F2, and F3) were formulated and fed to cultured shrimp to investigate the ability of melanin to protect shrimp from WSSV. The obtained results showed that F2 had a protection rate of 64% at day 7 and 62% at day 10 after virus challenge. The protection ability of the feedstuff depended on the amount of melanin consumed by shrimp. Moreover, our results also demonstrated that the transcription level of the VP28 gene, which codes for the VP28 protein, a representative for the presence of WSSV, was significantly decreased in shrimp fed F2. Taken together, our study suggests that melanin-containing diets may be applied in aquaculture to protect shrimp against WSSV infection; further, combined protocols with the simultaneous use of melanin-containing diets and other protectants should be studied and applied to increase the protection efficiency.

SiO2-coated Fe3O4 nanoparticles (Fe3O4@SiO2 NPs) were successfully synthesized using ultrasound in order to extract DNA from cancer tissues for application in diagnostics. The core 10.7-nm-diameter Fe3O4 nanoparticles were synthesized by co-precipitation of Fe3+ and Fe2+ as reaction substrates and NH4OH as precipitant, then coated with a thin layer of amorphous silica by a modified Stober method. Further SiO2 coating using alkaline hydrolysis of tetraethyl orthosilicate in ethanol and water mixture was accelerated in the presence of a 37-kHz ultrasound, resulting in the NPs having different sizes of 14.5 nm (version M1), 24.4 nm (version M2), and 34.9 nm (version M3) with saturation magnetization values of 50.2 emu/g, 18.6 emu/g, 10.3 emu/g, respectively. Among the three Fe3O4@SiO2 NPs versions, the M1 NPs allowed extraction of DNAs from 10 mg formalin-fixed and paraffin-embedded (FFPE) tissues of nasopharyngeal carcinoma patients with the highest recovery of about 100–500 ng/μl and good purity (A260/A280: 1.8–1.9). The extracted DNAs could be used as templates for downstream amplification of 252-bp sequencing specifically for the Braf cancer biomarker gene using polymerase chain reaction (PCR), as well as detection of the pathogenic Epstein–Barr virus (EBV) and the human papilloma-virus (HPV) using real-time PCR. DNA extraction recoveries of both EBV and HPV using Fe3O4@SiO2 NPs M1 were significantly better that those using commercialized Fe3O4@SiO2 microbeads, as indicated by lower threshold cycles of all fluorescent signals including fluorescein amidite (FAM) dye representative for EBV infection, hexachlorofluorescein (HEX) dye representative for β-globin (internal control), and SYBR Green dye representative for HPV infection in tested clinical samples from patients with nasopharyngeal carcinoma (NPC).