Sericin can reduce hippocampal neuronal apoptosis by activating the Akt signal transduction pathway in a rat model of diabetes mellitus

In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels significantly reduced, neuronal apoptosis in the hippocampal CA1 region decreased, hippocampal phosphorylated Akt and nuclear factor kappa B expression were enhanced, but Bcl-xL/Bcl-2 associated death promoter expression decreased. Results demonstrated that sericin can reduce hippocampal neuronal apoptosis in a rat model of diabetes mellitus by regulating abnormal changes in the Akt signal transduction pathway.

Molecular identifi cation and population diff erentiation of Aurelia spp.ephyrae in sea cucumber aquaculture ponds of northern China

Aurelia spp.ephyrae have been reported to form blooms in sea cucumber aquaculture ponds in the Bohai and Yellow Seas.To identify the species,we carried out a genetic analysis of Aurelia spp.ephyrae and medusae based on mitochondrial 16 S rRNA gene.Samples offour Aurelia sp.ephyrae populations were collected in sea cucumber aquaculture ponds and samples offour Aurelia sp.medusae populations were collected in coastal waters.Using a BLASTn search,we found that both the ephyrae collected in the aquaculture ponds and medusae collected in coastal waters belong to Aurelia coerulea.Seventeen haplotypes were recovered from the 16 S rRNA gene.The overall haplotype diversity and nucleotide diversity of the 166 A.coerulea individuals were 0.686%and 0.329%,respectively,indicating high haplotype diversity and low nucleotide diversity.Moreover,the haplotype diversity of ephyrae populations were generally lower than that of medusae populations with close sampling points.The genetic differentiation between ephyrae populations collected in the sea cucumber aquaculture ponds and A.coerulea medusae collected in coastal waters was not significant,suggesting the ephyrae populations in the sea cucumber culture ponds were part of the same genetic group as the medusae populations in the coastal waters.Phylogeographic analysis of the 16 S rRNA region revealed that there was no significant correlation between the haplotypes and the geographic distribution of populations.Pairwise fixation index values showed significant genetic differentiation and limited gene flow between A.coerulea population of Weifang and other locations.

Application of DNA metabarcoding to characterize the diet of the moon jellyfish Aurelia coerulea polyps and ephyrae

Dietary studies of polyps and ephyrae are important to understand the formation and magnitude of jellyfish blooms and provide important insights into the marine food web.However,the diet of polyps and ephyrae in situ is largely unknown.Here,prey species of the polyps and ephyrae of the moon jellyfish Aurelia coerulea in situ were identified using high-throughput DNA sequencing techniques.The results show that A.coerulea polyps and ephyrae consume a variety of prey items.The polyps consume both planktonic and benthic prey,including hydromedusae,copepods,ciliates,polychaetes,stauromedusae,and phytoplankton.A.coerulea ephyrae mainly feed on copepods and hydromedusae.Gelatinous zooplankton,including Rathkea octopunctata and Sarsia tubulosa,were frequently found as part of the diet of A.coerulea polyps and ephyrae.The utilization of highthroughput sequencing technique is a useful tool for studying the diet of polyps and ephyrae in the field,complementing the traditional techniques towards a better understanding of the complex role of gelatinous animals in marine ecosystems.

Bacterial communities associated with hydromedusa Gonionemus vertens in diff erent regions in Chinese coastal waters

Bacteria communities in cnidarian jellyfi sh can be harmful to many important aquaculture species,as they can be key vectors of bacterial pathogens.However,our knowledge of bacterial communities associated with jellyfi sh in culture ponds and their potential roles in the regulation of aquaculture species remains unclear.In this study,sequencing based on the bacterial 16S rRNA gene was used to investigate the composition and variation of the bacterial communities associated with hydromedusa Gonionemus vertens in sea cucumber culture ponds and natural marine environment.The associated bacterial communities of G.vertens from the culture ponds in the Yellow Sea and Bohai Sea had signifi cantly diff erent compositions,when compared with those from ambient seawater environment.Furthermore,bacterial communities associated with G.vertens had similar diversity and composition in culture ponds and natural marine environment in the Yellow Sea.There were 31 unique bacterial biomarkers identifi ed in three locations.The major communities were highly abundant in Kiloniellales,Octadecabacter,Polynucleobacter,and Polaribacter,and are related to the environmental information processing.Pathogen candidates such as Vibrionales and Chlamydiales had notably low relative abundances(<1%).The venom of the jellyfi sh was considered responsible for damage to the aquaculture.This study provides important data to help assess the impact of cnidarians-associated bacterial communities on pond aquaculture and the infl uences on material cycling and energy fl ow in marine ecosystems.

Abscisic Acid Antagonizes Ethylene Production through the ABI4-Mediated Transcriptional Repression of ACS4 and ACS8 in Arabidopsis

Increasing evidence has revealed that abscisic acid （ABA） negatively modulates ethylene biosynthesis, although the underlying mechanism remains unclear. To identify the factors involved, we conducted a screen for ABA-insensitive mutants with altered ethylene production in Arabidopsis. A dominant allele of ABI4, abi4-152, which produces a putative protein with a 16-amino-acid truncation at the C-terminus of ABI4, reduces ethylene production. By contrast, two recessive knockout alleles of ABI4, abi4-102 and abi4-103, result in increased ethylene evolution, indicating that ABI4 negatively regulates ethylene produc- tion. Further analyses showed that expression of the ethylene biosynthesis genes ACS4, ACSS, and AC02 was significantly decreased in abi4-152 but increased in the knockout mutants, with partial dependence on ABA. Chromatin immunoprecipitation-quantitative PCR assays showed that ABI4 directly binds the pro- moters of these ethylene biosynthesis genes and that ABA enhances this interaction. A fusion protein containing the truncated ABI4-152 peptide accumulated to higher levels than its full-length counterpart in transgenic plants, suggesting that ABI4 is destabilized by its C terminus. Therefore, our results demon- strate that ABA negatively regulates ethylene production through ABI4-mediated transcriptional repression of the ethylene biosynthesis genes ACS4 and ACS8 in Arabidopsis.