Transcriptome profiling reveals the developmental regulation of NaCl-treated Forcipomyia taiwana eggs.

BACKGROUND: The biting midge, Forcipomyia taiwana, is one of the most annoying blood-sucking pests in Taiwan. Current chemical control methods only target the adult, not the immature stages (egg to pupa), of F. taiwana. Discovering new or alternative tactics to enhance or replace existing methods are urgently needed to improve the effectiveness of F. taiwana control. The egg is the least understood life stage in this pest species but may offer a novel point of control as addition of NaCl to the egg environment inhibits development. Thus, the objective of this study was to use RNA profiling to better understand the developmental differences between wild-type melanized (black) and NaCl-induced un-melanized (pink), infertile F. taiwana eggs. RESULTS: After de novo assembly with Trinity, 87,415 non-redundant transcripts (Ft-nr) with an N50 of 1099 were obtained. Of these, 26,247 (30%) transcripts were predicted to have long open reading frames (ORFs, defined here as ≥300 nt) and 15,270 (17.5%) transcripts have at least one predicted functional domain. A comparison between two biological replicates each of black and pink egg samples, although limited in sample size, revealed 5898 differentially expressed genes (DEGs; 40.9% of the transcripts with long ORFs) with ≥2-fold difference. Of these, 2030 were annotated to a Gene Ontology biological process and along with gene expression patterns can be separated into 5 clusters. KEGG pathway analysis revealed that 1589 transcripts could be assigned to 18 significantly enriched pathways in 2 main categories (metabolism and environmental information processing). As expected, most (88.32%) of these DEGs were down-regulated in the pink eggs. Surprisingly, the majority of genes associated with the pigmentation GO term were up-regulated in the pink egg samples. However, the two key terminal genes of the melanin synthesis pathway, laccase2 and DCE/yellow, were significantly down-regulated, and further verified by qRT-PCR. CONCLUSION: We have assembled and annotated the first egg transcriptome for F. taiwana, a biting midge. Our results suggest that down-regulation of the laccase2 and DCE/yellow genes might be the mechanism responsible for the NaCl-induced inhibition of melanization of F. taiwana eggs.

Phytochemical composition and larvicidal activity of essential oils from herbal plants.

MAIN CONCLUSION: The essential oils (EOs) of Plectranthus amboinicus showed the highest larvicidal activity among four herbal plants studied and ß-caryophyllene might be the major component responsible for its differential toxicity to the larvae of Culex quinquefasciatus and Aedes Aegypti. Mosquitoes act as vectors for many life-threatening diseases, including malaria, dengue fever, and Zika virus infection. Management of mosquitoes mainly relies on synthetic insecticides, which usually result in the rapid development of resistance; therefore, alternative mosquito control strategies are urgently needed. This study characterized the major component of essential oils (EOs) derived from the vegetative parts of four herbal plants and their larvicidal activity toward important mosquito vectors. The EOs were extracted by hydro-distillation and subjected to gas chromatography-mass spectrometry (GC-MS) analysis and a larvicidal activity assay toward Aedes aegypti, Ae. albopictus and Culex quinquefasciatus. In total, 14, 11, 11 and 9 compounds were identified from the EOs of Plectranthus amboinicus, Mentha requienii, Vitex rotundifolia and Crossostephium chinense, respectively. The EOs derived from four herbal plants exhibited remarkable larvicidal activity against the three mosquito species. In particular, the EOs of P. amboinicus showed the highest larvicidal activity, and the larvae of Cx. quinquefasciatus were more sensitive to the P. amboinicus EOs than that of Ae. Aegypti. Although carvacrol (61.53%) was the predominant constituent of the P. amboinicus EOs, its precursors, γ-terpinene (8.51%) and p-cymene (9.42%), exhibited the most larvicidal activity toward Ae. aegypti and Cx. quinquefasciatus. However, ß-caryophyllene (12.79%) might be the major component responsible for the differential toxicity of the P. amboinicus EOs, as indicated by the significant differences in its LC50 values toward both mosquitoes. Information from these studies will benefit the incorporation of EOs into integrated vector management.

Aspartate aminotransferase to platelet ratio index and sustained virologic response are associated with progression from hepatitis C associated liver cirrhosis to hepatocellular carcinoma after treatment with pegylated interferon plus ribavirin.

BACKGROUND: The aim of this study was to evaluate the clinically significant predictors of hepatocellular carcinoma (HCC) development among hepatitis C virus (HCV) cirrhotic patients receiving combination therapy. PATIENTS AND METHODS: One hundred and five compensated cirrhosis patients who received pegylated interferon plus ribavirin between January 2005 and December 2011 were enrolled. All the patients were examined with abdominal sonography and liver biochemistry at baseline, end of treatment, and every 3-6 months posttreatment. The occurrence of HCC was evaluated every 3-6 months posttreatment. RESULTS: A total of 105 patients were enrolled (mean age 58.3±10.4 years). The average follow-up time for each patient was 4.38 years (standard deviation 1.73 years; range 1.13-9.27 years). Fifteen (14.3%) patients developed HCC during follow-up period. Thirteen of them had high baseline aspartate aminotransferase to platelet ratio index (APRI) (ie, an APRI >2.0). Multivariate analysis showed that those without sustained virologic response (SVR) (hazard ratio [HR] 5.795; 95% confidence interval [CI] 1.370-24.5; P=0.017) and high APRI (HR 5.548; 95% CI 1.191-25.86; P=0.029) had a significantly higher risk of HCC occurrence. The cumulative incidence of HCC was significantly higher (P=0.009) in patients without SVR (3-year cumulative incidence 21.4%; 95% CI 7.4%-35.5%; 5-year cumulative incidence 31.1%; 95% CI 11.2%-51.1%) compared to those with SVR (3- and 5-year cumulative incidence 6.2%; 95% CI 0%-1.3%). Further, the cumulative incidence of HCC was significantly higher (P=0.006) in patients with high APRI (3-year cumulative incidence 21.8%; 95% CI 8.2%-35.3%; 5-year cumulative incidence 30.5%, 95% CI 11.8%-49.3%) compared to those with low APRI (3- and 5-year cumulative incidence 4.2%, 95% CI 0%-1.0%). CONCLUSION: In HCV-infected cirrhotic patients who received combination therapy, APRI and SVR are the two major predictors of HCC development.

Association of sustained virologic response with reduced progression to liver cirrhosis in elderly patients with chronic hepatitis C.

OBJECTIVE: We studied the effect of sustained virologic response (SVR) after treatment with pegylated-interferon (PEG-IFN) plus ribavirin on the development of liver cirrhosis in elderly patients with chronic hepatitis C (CHC). PATIENTS AND METHODS: This retrospective study enrolled 145 elderly CHC patients (aged ≥65 years) who were treatment-naïve and were treated with PEG-IFN plus ribavirin for 6 months between January 2005 and December 2011. Abdominal sonography was performed and liver biochemistry was studied at baseline, at the end of treatment, and every 3-6 months thereafter. The development of liver cirrhosis and related complications was evaluated at the follow-ups. The aspartate aminotransferase-to-platelet ratio index was used as a noninvasive maker for fibrosis. RESULTS: The mean patient age was 69.1±3.3 years, and the average follow-up time was 5.5 years (standard deviation: 2.5 years, range: 1.1-12.3 years). Ninety-five patients (65.5%) achieved SVR, and 26 (17.9%) discontinued treatment. Twenty-seven patients (18.6%) developed liver cirrhosis after treatment. Patients without SVR had significantly greater risk of liver cirrhosis than those with SVR (hazard ratio [HR]: 3.39, 95% confidence interval [CI]: 1.312-8.761, P=0.012). The difference in 3-year cumulative incidence of liver cirrhosis was 24.8% greater for patients without SVR (35.2%, 95% CI: 13.0-57.5, P=0.012) compared with those with SVR (10.4%, 95% CI: 3.1-17.7). There was a trend of a higher baseline aspartate aminotransferase-to-platelet ratio index score in patients who progressed to liver cirrhosis compared with those who did not progress (2.1±1.2 vs 1.6±1.3, P=0.055), but the difference failed to reach significance by Cox regression (adjusted HR: 1.285, 95% CI: 0.921-1.791, P=0.14). CONCLUSION: An SVR following PEG-IFN combination treatment can reduce the risk of liver cirrhosis in elderly CHC patients.

Aspergillus oryzae AoSO is a novel component of stress granules upon heat stress in filamentous fungi.

Stress granules are a type of cytoplasmic messenger ribonucleoprotein (mRNP) granule formed in response to the inhibition of translation initiation, which typically occurs when cells are exposed to stress. Stress granules are conserved in eukaryotes; however, in filamentous fungi, including Aspergillus oryzae, stress granules have not yet been defined. For this reason, here we investigated the formation and localization of stress granules in A. oryzae cells exposed to various stresses using an EGFP fusion protein of AoPab1, a homolog of Saccharomyces cerevisiae Pab1p, as a stress granule marker. Localization analysis showed that AoPab1 was evenly distributed throughout the cytoplasm under normal growth conditions, and accumulated as cytoplasmic foci mainly at the hyphal tip in response to stress. AoSO, a homolog of Neurospora crassa SO, which is necessary for hyphal fusion, colocalized with stress granules in cells exposed to heat stress. The formation of cytoplasmic foci of AoSO was blocked by treatment with cycloheximide, a known inhibitor of stress granule formation. Deletion of the Aoso gene had effects on the formation and localization of stress granules in response to heat stress. Our results suggest that AoSO is a novel component of stress granules specific to filamentous fungi. The authors would specially like to thank Hiroyuki Nakano and Kei Saeki for generously providing experimental and insightful opinions.