Suspended sediment concentration (SSC) is one of the most critical parameters in ocean ecological environment evaluation and it can be determined using ocean color remote sensing (RS). The purpose of this study is to develop a model that provides a reliable and sensitive evaluation of SSC retrieval using RS data. Data were acquired for and gathered from the Gulf of Bohai where SSC levels are relatively low with an average value below 30 mg·L −1. The study indicates that the most sensitive band to SSC levels in the study area is the NIR band of Landsat5 TM images. A quadratic polynomial semi-analytical model appears to be the best retrieval model based on the relationship between the inherent optical properties (IOPs) and apparent optical properties (AOPs) of water as described by the quasi-analytical algorithm (QAA). The model has a higher precision and effectiveness for SSC retrieval than data-driven statistical models, especially when SSC level is relatively high. The average relative error and the root mean square error (RMSE) are 12.32% and , respectively, while the correlation coefficient between observed and estimated SSC by the model is 0.95. Using the proposed retrieval model and TM data, SSC levels of the entire study region in the Gulf of Bohai were estimated. These estimates can serve as the baseline for efficient monitoring of the ocean environment in the future.

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important viral pathogens in the swine industry. Current antiviral strategies do not effectively prevent and control PRRSV. Recent reports show that microRNAs (miRNAs) play vital roles in viral infections by post transcriptionally regulating the expression of viral or host genes. Our previous research showed that non-muscle myosin heavy chain 9 (MYH9) is an essential factor for PRRSV infection. Using bioinformatic prediction and experimental verification, we demonstrate that MYH9 expression is regulated by the miRNA let-7f-5p, which binds to the MYH9 mRNA 3′UTR and may play an important role during PRRSV infection. To understand how let-7f-5p regulates PRRSV infection, we analyzed the expression pattern of both let-7f-5p and MYH9 in porcine alveolar macrophages (PAMs) after infection with either highly pathogenic PRRSV (HP-PRRSV) or classical type PRRSV (N-PRRSV) using a deep sequencing approach with quantitative real-time PCR validation. Our results showed that both HP-PRRSV and N-PRRSV infection reduced let-7f-5p expression while also inducing MYH9 expression. Furthermore, let-7f-5p significantly inhibited PRRSV replication through suppression of MYH9 expression. These findings not only provide new insights into the pathogenesis of PRRSV, but also suggest potential new antiviral strategies against PRRSV infection.

Viral cycle progression depends upon host-cell processes in infected cells, and this is true for bovine viral diarrhoea virus (BVDV), the causative agent of BVD that is a worldwide threat to the bovine industry. Heme oxygenase-1 (HO-1) is a ubiquitously expressed inducible isoform of the first and rate-limiting enzyme for heme degradation. Recent studies have demonstrated that HO-1 has significant antiviral properties, inhibiting the replication of viruses such as ebola virus, human immunodeficiency virus, hepatitis C virus, and porcine reproductive and respiratory syndrome virus. However, the function of HO-1 in BVDV infection is unclear. In the present study, the relationship between HO-1 and BVDV was investigated. In vitro analysis of HO-1 expression in BVDV-infected MDBK cells demonstrated that a decrease in HO-1 as BVDV replication increased. Increasing HO-1 expression through adenoviral-mediated overexpression or induction with cobalt protoporphyrin (CoPP, a potent HO-1 inducer), pre- and postinfection, effectively inhibited BVDV replication. In contrast, HO-1 siRNA knockdown in BVDV-infected cells increased BVDV replication. Therefore, the data were consistent with HO-1 acting as an anti-viral factor and these findings suggested that induction of HO-1 may be a useful prevention and treatment strategy against BVDV infection.

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