Ecotoxicity Assessment of Fe3O4 Magnetic Nanoparticle Exposure in Adult Zebrafish at an Environmental Pertinent Concentration by Behavioral and Biochemical Testing.

Magnetic Nanoparticles (MNPs) are widely being investigated as novel promising multifunctional agents, specifically in the fields of development for theranostics, electronics, waste water treatment, cosmetics, and energy storage devices. Unique, superior, and indispensable properties of magnetization, heat transfer, and melting temperature make MNPs emerge in the field of therapeutics in future healthcare industries. However, MNPs ecotoxicity as well as behavioral toxicity is still unexplored. Ecotoxicity analysis may assist investigate MNPs uptake mechanism and its influence on bioavailability under a given set of environmental factors, which can be followed to investigate the biomagnification of MNPs in the environment and health risk possessed by them in an ecological food chain. In this study, we attempted to determine the behavioral changes in zebrafishes at low (1 ppm) or high (10 ppm) concentration levels of Fe3O4 MNPs. The synthesized Fe3O4 MNPs sized at 15 nm were characterized by the transmission electron microscope (TEM), the superconducting quantum interference device (SQUID) magnetometer, and the multiple behavior tests for novel tank, mirror biting, conspecific social interaction, shoaling, circadian rhythm, and short-term memory of zebrafish under MNPs chronic exposure were demonstrated. Low concentration MNP exposure did not trigger alteration for majority behavioral and biochemical tests in adult zebrafish. However, tight shoal groups were observed at a high concentration of MNPs exposure along with a modest reduction in fish exploratory behavior and a significant reduction in conspecific social interaction behavior. By using enzyme-linked immunosorbent assays (ELISA), we found a high dose of MNPs exposure significantly elevated cortisol, acetylcholine, and catalase levels while reducing serotonin, acetylcholine esterase, and dopamine levels in the brain. Our data demonstrates chronic MNPs exposure at an environmentally-relevant dose is relatively safe by supporting evidence from an array of behavioral and biochemical tests. This combinational approach using behavioral and biochemical tests would be helpful for understanding the MNPs association with anticipated colloids and particles effecting bioavailability and uptake into cells and organisms.

Zebrafish Mutants Carrying Leptin a (lepa) Gene Deficiency Display Obesity, Anxiety, Less Aggression and Fear, and Circadian Rhythm and Color Preference Dysregulation.

Leptin, a hormone secreted by peripheral adipose tissues, regulates the appetite in animals. Recently, evidence has shown that leptin also plays roles in behavioral response in addition to controlling appetite. In this study, we examined the potential function of leptin on non-appetite behaviors in zebrafish model. By using genome editing tool of Transcription activator-like effector nuclease (TALEN), we successfully knocked out leptin a (lepa) gene by deleting 4 bp within coding region to create a premature-translation stop. Morphological and appetite analysis showed the lepa KO fish display a phenotype with obese, good appetite and elevation of Agouti-related peptide (AgRP) and Ghrelin hormones, consistent with the canonical function of leptin in controlling food intake. By multiple behavior endpoint analyses, including novel tank, mirror biting, predator avoidance, social interaction, shoaling, circadian rhythm, and color preference assay, we found the lepa KO fish display an anxiogenic phenotype showing hyperactivity with rapid swimming, less freezing time, less fear to predator, loose shoaling area forming, and circadian rhythm and color preference dysregulations. Using biochemical assays, melatonin, norepinephrine, acetylcholine and serotonin levels in the brain were found to be significantly reduced in lepa KO fish, while the levels of dopamine, glycine and cortisol in the brain were significantly elevated. In addition, the brain ROS level was elevated, and the anti-oxidative enzyme catalase level was reduced. Taken together, by performing loss-of-function multiple behavior endpoint testing and biochemical analysis, we provide strong evidence for a critical role of lepa gene in modulating anxiety, aggression, fear, and circadian rhythm behaviors in zebrafish for the first time.

A Simple Method to Decode the Complete 18-5.8-28S rRNA Repeated Units of Green Algae by Genome Skimming.

Green algae, Chlorella ellipsoidea, Haematococcus pluvialis and Aegagropila linnaei (Phylum Chlorophyta) were simultaneously decoded by a genomic skimming approach within 18-5.8-28S rRNA region. Whole genomic DNAs were isolated from green algae and directly subjected to low coverage genome skimming sequencing. After de novo assembly and mapping, the size of complete 18-5.8-28S rRNA repeated units for three green algae were ranged from 5785 to 6028 bp, which showed high nucleotide diversity (π is around 0.5-0.6) within ITS1 and ITS2 (Internal Transcribed Spacer) regions. Previously, the evolutional diversity of algae has been difficult to decode due to the inability design universal primers that amplify specific marker genes across diverse algal species. In this study, our method provided a rapid and universal approach to decode the 18-5.8-28S rRNA repeat unit in three green algal species. In addition, the completely sequenced 18-5.8-28S rRNA repeated units provided a solid nuclear marker for phylogenetic and evolutionary analysis for green algae for the first time.

The complete mitogenome of nereid worm, Neanthes glandicincta (Annelida: Nereididae).

In this study, the complete mitogenome sequence of nereid worm, Neanthes glandicincta (Annelida: Nereididae), has been decoded for the first time by PCR amplification and Sanger sequencing methods. The overall base composition of N. glandicincta mitogenome is 31.5% for A, 22.2% for C, 14.5% for G and 31.7% for T, and has GC content of 36.7%. The assembled mitogenome, consisting of 16,126 bp, has unique 13 protein-coding genes (PCGs), 22 transfer RNAs and 2 ribosomal RNAs genes. The complete mitogenome of N. glandicincta shows 65% identities to Namalycastis abiuma. All PCGs, tRNA and rRNA genes were encoded on H-strand. The potential D-loop is 1625 bp in length and located between tRNA-Gly and tRNA-Met. The complete mitogenome provides essential and important DNA molecular data for further phylogenetic and evolutionary analysis for Annelida.

The complete mitogenome of sea hares, Dolabella auricularia (Mollusca: Aplysiidae).

In this study, the complete mitogenome sequence of sea hares, Dolabella auricularia (Mollusca: Aplysiidae), has been decoded for the first time by low coverage whole genome sequencing method. The overall base composition of D. auricularia mitogenome is 31.5% for A, 14.0% for C, 16.4% for G, and 38.0% for T, and has low GC content of 30.5%. The assembled mitogenome, consisting of 14,598 bp, has unique 13 protein-coding genes (PCGs), 22 transfer RNAs, and two ribosomal RNAs genes. The D. auricularia has the common mitogenome gene organization and feature of Aplysiidae. The complete mitogenome of D. auricularia provides essential and important DNA molecular data for further phylogenetic and evolutionary analysis for Aplysiidae.

Genome skimming yields the complete mitogenome of Chromodoris annae (Mollusca: Chromodorididae).

In this study, the complete mitogenome sequence of sea slug, Chromodoris annae (Mollusca: Chromodorididae), has been decoded for the first time by genome skimming method. The overall base composition of C. annae mitogenome is 30.6% for A, 14.5% for C, 17.8% for G, and 37.2% for T, and has GC content of 32.2%. The assembled mitogenome, consisting of 14,260 bp, has unique 13 protein-coding genes (PCGs), 22 transfer RNAs, and two ribosomal RNAs genes. The C. annae has the common mitogenome gene organization and feature of Chromodorididae. The complete mitogenome of C. annae provides essential and important DNA molecular data for further phylogenetic and evolutionary analysis for sea slugs.

Next generation sequencing yields the complete mitogenome of nereid worm, Namalycastis abiuma (Annelida: Nereididae).

In this study, the complete mitogenome sequence of nereid worm, Namalycastis abiuma (Annelida: Nereididae), has been decoded for the first time by low coverage genome sequencing method. The overall base composition of N. abiuma mitogenome is 30.8% for A, 24.6% for C, 14.0% for G and 30.6% for T, and has GC content of 38.6%. The assembled mitogenome, consisting of 15 265 bp, has unique 13 protein-coding genes (PCGs), 21 transfer RNAs and two ribosomal RNA genes. The complete mitogenome of N. abiuma shows 69% identities to Tylorrhynchus heterochaetus. All PCGs, tRNA and rRNA genes were encoded on H-strand. The potential D-loop is 827 bp in length and located between tRNA-Gly and tRNA-Trp. The complete mitogenome provides essential and important DNA molecular data for further phylogenetic and evolutionary analysis for Annelida.

[Distribution pattern of microphytoplankton in the Bering Sea during the summer of 2010].

Based on the analysis of 70 water samples collected by the Chinese icebreaker Xuelong in the areas of 52 degrees 42.29'-65 degrees 30.23' N and 169 degrees 20.85' E-179 degrees 30.37' W in the Bering Sea during the Chinese Arctic Research Expedition on July 10-19, 2010, a total of 143 phytoplankton species were identified, including 95 diatom species belonging to 37 genera, 44 dinoflagellate species belonging to 15 genera, 2 Chlorophyta species belonging to 2 genera, 1 Euglenophyta belonging to 1 genus, and 1 Chrysophyta species belonging to 1 genus. The cluster analysis revealed that the phytoplankton in the study areas could be divided as oceanic and shallow water groups. The oceanic group found in the western North Pacific Ocean and the Bering Basin was dominated by the boreal oceanic species such as Neodenticula seminae and Chaetoceros atlanticus and the cosmopolitan species such as Thalassionema nitzschioides and Chaetoceros compressus, with the characteristics of low abundance and high evenness of diversified species. The shallow water group found in the continental shelf and slope of Bering Sea was mostly composed of the pan-arctic neritic species such as Thalassiosira nordenskioldi and Chaetoceros furcellatus and the cosmopolitan species such as Leptocylindrus danicus and Chaetoceros curvisetus, with the characteristics of low species diversity and evenness index due to the high abundance in certain species. The phytoplankton abundance in the surface water layer distributed unevenly among the stations, ranging from 950 to 192400 cells x L(-1) and with an average of 58722 cells x L(-1). Horizontally, the abundance distribution trend was decreased in the order of the Bering Sea shelf, the Bering Sea slope, the Bering Sea basin, and the western North Pacific Ocean. Vertically, the abundance was lower in surface layer and maximized in the thermocline, suggesting that the phytoplankton abundance in vertical distribution varied with the regional thermocline.

[Community composition of phytoplankton in Fujian-Guangdong coastal upwelling region in summer and related affecting factors].

Based on the investigation data of 133 samples from 30 grid stations in the Fujian-Guangdong coastal upwelling region (21.6 degrees - 24.3 degrees N,115.7 degrees -118.7 degrees E) in 11-16 June 2009, this paper studied the phytoplankton species composition and cell abundance in the region in three dimensions (vertical, horizontal, and sectional), and approached their relations with major environmental factors. A total of 159 taxa belonging to 85 genera of 4 phyla were identified, among which, diatom was predominant, followed by dinoflagellate. Cyanophyceae mainly composed of Trichodesmium also occupied a greater proportion, but Chrysophyceae was only checked out in the upper 10 m water layer at coastal stations. The dominant species were Rhizosolenia alata f. gracillma, Thalassionema nitzschioides, Pseudonitzschia pungens, Skeletonema costatum, Thalassionema frauenfeldii, Paralia sulcata, Guinadia striata, Trichodesmium thiebautii, Ceratium fusus, and Gyrodinium spirale. Most of the phytoplankton taxa were cosmopolitan species, followed by warm-water species, while tropic high-salinity or oceanic eurythermal species were lesser. The cell abundance of the phytoplankton was average of 67.59 x10(2) ind x L(-1). In vertical profile, the cell abundance of the phytoplankton was the highest in surface water, and decreased with water depth. In horizontal and sectional profiles, the cell abundance had no definite patterns, but the high abundance region was in Nanao Island water area, being anastomosed with the center of upwelling region, which indicated that the weak and small intensity of deep-sea water upwelling caused lesser phytoplankton cell abundance and superposition. The comparatively high phytoplankton cell abundance in the four sections (B, C, D, E) along Nanao-Zhangpu was resulted from the upwelling from Taiwan Bank. The phytoplankton cell abundance had a significant positive correlation with the PO4(3-) concentration in the upper 10 m water layer, but no correlation with the dissolved inorganic nitrogen (DIN) concentration. Thereby, to study the eco-physiological responses of phytoplankton species to nutrient stress would be helpful to reveal the formation mechanism of algal bloom in upwelling region.