ABSTRACT
Pyropia yezoensis is commercially the most important edible red alga in China, and red rot disease is viewed as one of the major constraints for its cultivation. Microbes within the oomycetic genus Pythium have been reported as the causative agents for this disease; however, little is known about the interactions between the disease and the epiphytic and planktonic bacterial communities. In the present study, bacterial communities associated with uninfected, locally infected, and seriously infected thalli collected from cultivation farms, and within seawater adjacent to the thalli, were investigated using in-depth 16S ribosomal RNA (rRNA) gene sequencing in conjunction with assessing multiple environmental factors. For both thalli and seawater, uninfected and infected communities were significantly different though alpha diversity was similar. Phylogenetic differences between epiphytic bacterial communities associated with P. yezoensis were mainly reflected by the relative changes in the dominant operational taxonomic units (OTUs) assigned as genus Flavirhabdus, genus Sulfitobacter, and family Rhodobacteraceae. The prevalent OTUs in seawater also differed in relative abundance across the communities and were affiliated with diverse taxa, including the phyla Actinobacteria, Verrucomicrobia, and Bacteroidetes, and the classes Alpha- and Gamma-proteobacteria. The differentiation of bacterial communities associated with P. yezoensis and seawater was primarily shaped by reactive silicate (RS) content and salinity, respectively. In particular, 14 potential indicators (two OTUs on P. yezoensis and twelve OTUs in seawater) were identified that significantly differentiated P. yezoensis health statuses and correlated with environmental changes. Overall, the present study provides insights into the alterations of bacterial communities associated with P. yezoensis and surrounding seawater co-occurring with red rot disease. Observed changes were closely associated with health status of algal host, and highlight the potential of using community differentiation to forecast disease occurrence.
ABSTRACT
OBJECTIVE: To investigate the effects of simvastatin (SIM)on cardiac hypertrophy and association with calcium channel modulation in rats with myocardial hypertrophy. METHODS: Myocardial hypertrophy was induced by abdominal aortic constriction (AAC) in adult SD rats. Following groups were studied (n=8 each): sham group, AAC group, AAC+ verapamil group (10 mg x kg(-1) x d(-1) per gavage for 4 weeks), AAC +SIM group (10 mg x kg(-1) x d(-1) per gavage for 4 weeks) AAC + SIM + mevalonic acid (50 mg x kg(-1) x d(-1) per gavage for 4 weeks) group. Systolic blood pressure (SBP), echocardiography, heart weight/body weight (HW/BW) and left ventricle weight/body weight (LVW/BW) ratios were measured. The protein and mRNA expressions of L-type calcium channel subunit alpha1 C and T-type calcium channel subunit alpha1 G and alpha1 H were detected by Western blot and RT-PCR respectively. RESULTS: SBP, HW/BW, LVW/BW, IVS and LVPW thickness, left ventricular weights were significantly increased in AAC rats and these effects could be significantly reduced by verapamil and SIM. The protein and mRNA expressions of alpha1 G and alpha1 H were significantly increased in AAC rats which could also be significantly inhibited by SIM or verapamil. The effects of SIM could be blocked by cotreatment with mevalonic acid. Protein and mRNA expressions of L-type calcium channel alpha1 C were similar among groups. CONCLUSION: Similar as verapamil, SIM could prevent AAC induced cardiac hypertrophy, possibly via inhibiting T-type calcium channel subunit alpha1 G and alpha1 H re-expression.
