Identification of A Novel CYP4V Gene In The Polychaete Perinereis Aibuhitensis: Transcriptional Comparison With CYP4B Exposed To PAHs

Polychaete worms can biotransform polycyclic aromatic hydrocarbons (PAHs) in environments, and the cytochrome P450 (CYP) enzyme plays an important role in this process. Herein, a novel cytochrome P450 gene was identified and characterized from the polychaete worm Perinereis aibuhitensis. The full-length cDNA, which is named CYP4V82, is 1709 bp encoding a protein of 509 amino acids and has high similarity to CYP4V. The expression levels of CYP4V82 and CYP4BB4 (a CYP gene identified from P. aibuhitensis in a previous study, Chen et al., 2012) exposure to various concentrations of benzo[α]pyrene (B[α]P) (0.5, 2, 4, and 8 μg/L) and same mass concentrations of fluoranthene (Flu, 3.2 μg/L), phenanthrene (Phe, 2.9 μg/L), B[α]P (4.0 μg/L) were detected to identify the function of the CYP4 family in P. aibuhitensis. Compared with CYP4BB4, CYP4V82 mRNA was minimally expressed on day 7 but highly sensitive on day 14. Notably, the expression level of CYP4V82 and CYP4BB4 was relatively different in response to PAHs with different benzene rings of the same concentration. The expression of CYP4V82 in the B(a)P group was the highest, while that of CYP4BB4 in the Phe group was relatively higher than the two other groups. These findings suggest that PAHs are associated with the induction of CYP4V82 and CYP4BB4 expressions, which may have different efficiencies in the detoxification of PAHs.

Hemoglobin Extracted From Perinereis aibuhitensis Acts as a Cell Culture Medium Supplement to Reduce Apoptosis

The environmental oxygen concentration is a crucial factor affecting cell proliferation. Owing to the reversible binding property of hemoglobin to oxygen, it can be utilized to regulate the oxygen concentration in vitro, and its ability to reduce apoptosis can be evaluated. In this study, a process comprising isolation, purification, and extraction was used to obtain hemoglobin from Perinereis aibuhitensis, a polychaete invertebrate. Extracts were separated and characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Extract component identity was confirmed by matrix-assisted laser desorption time-of-flight mass spectrometry analysis, with the molecular weight determined as 412,216.6875 Da. The oxygen carrying capacity of P. aibuhitensis hemoglobin was comparable with that of human hemoglobin. P. aibuhitensis hemoglobin remarkably downregulated the apoptosis rate. Reactive oxygen species (ROS) assays confirmed the reduction in ROS production, enabling a better elucidation of the mechanism underlying the decrease in apoptosis. These results suggested that P. aibuhitensis hemoglobin is a natural oxygen carrier, that, owing to its low-cost and accessibility, can be considered a candidate for culture medium supplement to reduce the apoptosis rate.

The Sediment Selectivity of Perinereis aibuhitensis Larvae: Active or Passive?

The selectivity of Perinereis aibuhitensis larvae on different sediment types was studied using an experimental behavioral device in the lab. There were six types of sediment with different organic matter content: 2.19, 2.30, 2.86, 3.25, 3.51, and 5.52%. The results indicated significant differences in the six treatments’ organic matter content (p < 0.05). When the P. aibuhitensis larvae initially attached to the sediment, the larvae’s density showed no significant difference among the six treatments. The density of larvae decreased gradually during the experimental period. It increased with the increasing organic matter content in sediment at every sampling time, but there was no significant difference (p > 0.05). The larvae’s specific growth rate in the first month was significantly higher than those in the second and third months (p < 0.05). The mortality showed no significance at different sediments in equal sampling times, but the mortality was lower in high organic matter content sediments. This study showed that the P. aibuhitensis larvae did not make an active selection; random selection happened when initially attached to the sediment with different organic matter contents. Higher organic matter content in the sediment was more conducive to larvae survival, and the organic matter content is the limitation factor on the mortality and the density. The different densities in the natural habitat of P. aibuhitensis might occur due to the passive selection by the environment.

Review of some Perinereis Kinberg, 1865 (Annelida: Nereididae) species of Group 2 sensu Hutchings, Reid & Wilson, 1991 from the Eastern and South-eastern Asian seas

The present study reviews Perinereis Group 2 species from the Eastern and South-eastern Asian seas based on morphological analysis of the types, non-types and original descriptions, and the use of molecular evidence (COI and 16S rDNA) from newly collected material. These species are characterized by having two bar-shaped paragnaths on pharyngeal area VI, which are often deemed conical when small and pointed, triggering misidentifications as to Neanthes species. New terminology and definition for this particular type of bars are proposed, and the generic position of some resembling Neanthes species is also re-assessed. Five species are transferred to Perinereis: Perinereis babuzai comb. nov., P. belawanensis comb. nov., P. kinmenensis comb. nov., P. shigungensis comb. nov. and P. vitabunda comb. nov. ‘Perinereis aibuhitensis’ species group is newly proposed by encompassing species having proximal dorsal ligule similar throughout the body, dorsal cirri short, and blades of heterogomph falcigers straight with long terminal tooth forming a distinct tendon. Perinereis belawanensis comb. nov., P. linea and P. vitabunda comb. nov. are redescribed. Perinereis linea is regarded as a senior synonym of Nereis (Neanthes) orientalis and Perinereis vancaurica tetradentata based on type material, whereas its exotic status in the Mediterranean Sea is questioned. An identification key to all currently valid species within Perinereis Group 2 is also provided.

Characterization, mRNA expression and nutritional regulation of a Δ6 fatty acyl desaturase-like gene by dietary DHA levels of Perinereis aibuhitensis (Gube, 1878)

The Δ6 fatty acyl desaturase (Δ6 Fad) enzyme plays an important role in the pathways for the biosynthesis of the highly unsaturated fatty acids (HUFA) by converting linoleic (LA, 18:2n-6) and α-linolenic (LNA, 18:3n-3) acids to 18:3n-6 and 18:4n-3, respectively. In the present study, a Δ6 Fad-like gene was cloned and its characterisation, tissue expression and nutritional regulation by dietary DHA (docosahexaenoic acid) levels were analysed in the clamworm Perinereis aibuhitensis. The full-length cDNA was 1535 bp including a 1335 bp open reading frame (ORF) encoding a polypeptide of 444 amino acids, a 113 bp 50’-UTR and an 87 bp 3’-UTR with a poly (A) tail. Sequence comparison revealed that the predicted protein shared higher homologies with Δ6 Fad from Apostichopus japonicus with 56% identify. The tissue distribution of P. aibuhitensis Δ6 Fad-like mRNA was found predominantly in intestine, followed by head, esophagus, stomach and other tissues. Quantitative real-time PCR showed that the Δ6 Fad-like transcriptional levels in intestine gradually decreased with increased content of dietary DHA.

The effects of organic matter concentration on sediment reworking of Perinereis aibuhitensis : a mesocosm study

<p>The organic matter (OM) concentration is one of the most important factors influencing benthic organism sediment reworking during bioturbation. This study was designed to evaluate differences in sediment reworking rate of Perinereis aibuhitensis based on quantification of its pellet production (PP) and OM transport rate from ambient sediment to the surface due to its feeding. The mesocosm experiment was conducted in acrylic container (15×1×20 cm) with two treatments (high OM treatment and low OM treatment) and each treatment had ten replicates. The pellets in each container were removed 2h before the beginning of the pellet collection, and then newly produced pellets were collected every 2 h during 24 h at each treatment. The mean grain size of pellets (5.1 ∅) was smaller than that of ambient sediment particles (5.9 ∅), and the mean OM concentration was much higher in pellet (0.69% for C and 0.06% for N) than in ambient sediment (0.46% for C and 0.05% for N). Since an organism cannot produce more organic matter than it ingests, production of organically enriched pellets by this species indicates selective ingestion. The overall OM transport rate was 0.7 g C m<sup>-2</sup> day<sup>-1</sup> in carbon and 0.06 g N m<sup>-2</sup> day<sup>-1 </sup>in nitrogen, respectively. The daily PP was much higher in high OM treatment than that of low OM treatment with mean values of 0.007 and 0.002 g ind.<sup>-1</sup> h<sup>-1</sup>, respectively. It is expected that Perinereis feeding activity strongly depended on OM concentrations. The overall sediment reworking rate based on the pellet production was much higher in high OM concentration (0.005 mm day<sup>-1</sup>) than in low OM (0.001 mm day<sup>-1</sup>) concentration.</p>