Comparison of environmental DNA metabarcoding and bottom trawling for detecting seasonal fish communities and habitat preference in a highly disturbed estuary

Environmental DNA (eDNA) metabarcoding has been used to study fish diversity in various aquatic ecosystems. However, studies on fish community structure in estuarine ecosystems have not been well corroborated by eDNA metabarcoding, and comparisons with bottom trawling are lacking. We used eDNA sequencing of mitochondrial 12S rRNA gene to investigate the fish species composition and relative abundance, community temporal and spatial variations, and community-environment relationship of the Pearl River Estuary during spring and autumn. Then, we compared these results with those obtained by bottom trawling. Results showed that eDNA metabarcoding detected more species (214 vs 90), genera (148 vs 69), families (67 vs 38), and a significantly greater number of species at each station. Results of nonmetric multidimensional scaling and permutational multivariate analysis of variance based on the Bray-Curtis dissimilarity index indicated that eDNA metabarcoding detected significant differences in fish communities between spring and autumn, which was similar to the bottom trawling results. eDNA metabarcoding revealed that the fish community differences increased with spatial distance among stations. However, when we compared results of the two methods using principal coordinates analysis, we observed discordance in the fish community differences among sites. eDNA metabarcoding may provide new insights into and a more detailed and comprehensive understanding of estuarine ecosystems. Additionally, eDNA metabarcoding revealed that salinity and temperature were closely linked to fish community composition in spring, and salinity and dissolved oxygen were closely associated with fish community composition in autumn. In conclusion, eDNA metabarcoding may represent an important supplementary method, or even replace current methods, to monitor and assess temporal and spatial variation of fish communities and infer the community-environment relationship, especially in estuarine ecosystems, which are difficult to sample using traditional methods

OsMIOX, a myo-inositol oxygenase gene, improves drought tolerance through scavenging of reactive oxygen species in rice (Oryza sativa L.)

Myo-inositol oxygenase (MIOX), a unique monooxygenase, catalyzes the oxidation of myo-inositol to d-glucuronic acid. However, the protective role of MIOX in plants against oxidative stress or drought stress remains unknown. In this study, the functional characterization of MIOX obtained from the cDNA library of upland rice (Oryza sativa L. cv. IRAT109), was performed. OsMIOX was expressed predominantly in the roots and induced by drought, H2O2, salt, cold and abscisic acid. The transgenic rice lines overexpressing OsMIOX showed obviously improved growth performance in the medium containing 200 mM mannitol. Further, the survival rate of leaves from the transgenic rice lines was significantly higher than that of the wild type plants under polyethylene glycol treatment. It was discovered that the activity of ROS-scavenging enzymes and proline content, as well as the transcript levels of many ROS scavenging genes were significantly increased in transgenic plants compared to the wild type plants under drought stress conditions. Together, these data suggest that OsMIOX has a specific function in drought stress tolerance by decreasing oxidative damage

A template-stripped carbon nanofiber/poly(styrene-butadiene-styrene) compound for high-sensitivity pressure and strain sensing

Materials selection and microstructural design of the sensing part of flexible pressure sensors are of great significance in improving their performance. However, achieving synergy between the sensing material and the microstructure of the flexible sensors remains a challenge. Herein, compressible and stretchable sensors based on a carbon nanofiber/poly(styrene-butadiene-styrene) (CNF/SBS) compound are demonstrated with a template-stripped method for detecting various human motions, including pulses, finger bending and pressure distributions. Benefiting from the adjustable fingerprint microstructure and mass fraction of CNFs, the as-designed flexible pressure sensor dramatically achieves a high sensitivity of 769.2 kPa-1, a low detection limit of 5 Pa and high reliability of over 1000 cycles. Moreover, the flexible sensor based on CNF/SBS can be stretched due to the outstanding tensile properties of SBS. The enhanced stretchable sensor remarkably possesses a high gauge factor of 105.6 with a stretch range of 0%-300% and up to 600% elongation. Importantly, the proposed pressure and tension strain sensors are investigated to monitor vigorous human motion, revealing their tremendous potential for applications in flexible compressible and stretchable wearable electronics

Exploring the Spatial and Temporal Distribution of Frigate Tuna (<i>Auxis thazard</i>) Habitat in the South China Sea in Spring and Summer during 2015–2019 Using Fishery and Remote Sensing Data

Frigate tuna Auxis thazard fishery is considered a potential marine resource in the open South China Sea (SCS). However, little is known about the spatial and temporal distribution of its habitat, and how this may respond to environmental changes. Using fish survey and remote sensing data from 2015–2019, we applied generalized additive models to identify relationships between environmental factors and the distribution of A. thazard in the SCS. To examine seasonal patterns in the habitat of A. thazard in the SCS, we generated a habitat suitability index model using environmental factors screened by generalized additive models. Results showed that A. thazard migrates from south to north in the SCS, and its suitable habitat is patchily distributed. Significant environmental factors affecting the habitat of A. thazard distribution were different in different seasons; we demonstrated A. thazard to be sensitive to Chl-a in spring (optimum 0.155, optimal range ~0.1252–0.1840), and in summer to be sensitive to SST (optimum 30.405, optimal range ~29.789–31.021) and SSH (optimum 0.741, optimal range ~0.618–0.864). Suitable habitat in spring occurs mainly in northeastern areas, while in summer it occurs mainly around the southeastern Nansha Islands. Compared with that in spring, the area of suitable habitat increases in summer, as does the habitat suitability index of the entire sea area. These results improve our understanding of environmental factors that affect the distribution of A. thazard habitat in the SCS, and provide a scientific basis for the development and management of A. thazard resources

Enabling an integrated tantalum nitride photoanode to approach the theoretical photocurrent limit for solar water splitting

The feasibility of photoelectrochemical (PEC) water-splitting cells relies on the development of high-performance photoanodes. Significant progress has been made in the discovery of narrow bandgap semiconductors as promising photoanodes. However, the rational design of photoanode architecture that brings the potentials of narrow bandgap semiconductors into fruition for efficient PEC water oxidation still remains a key challenge. Herein, we show a highly efficient photoanode system consisting of a tantalum nitride (Ta3N5) semiconductor for light harvesting, hole-storage layers (Ni(OH)(x)/ferrhydrite) that mediate interfacial charge transfer from Ta3N5 to coupled molecular catalysts (Co cubane and Ir complex) for water oxidation and a TiOx blocking layer that reduces the surface electron-hole recombination. The integrated Ta3N5 photoanode exhibits a record photocurrent of 12.1 mA cm(-2) at 1.23 V vs. the reversible hydrogen electrode (RHE), which is nearly its theoretical photocurrent limit under sunlight (12.9 mA cm(-2)), suggesting that almost each pair of photogenerated charge carriers in Ta3N5 has been efficiently extracted and collected for solar water splitting

Overexpression of <i>OsMYB48-1</i>, a Novel MYB-Related Transcription Factor, Enhances Drought and Salinity Tolerance in Rice

<div><p>MYB-type transcription factors (TFs) play essential roles in plant growth, development and respond to environmental stresses. Role of MYB-related TFs of rice in drought stress tolerance is not well documented. Here, we report the isolation and characterization of a novel MYB-related TF, <i>OsMYB48-1</i>, of rice. Expression of <i>OsMYB48-1</i> was strongly induced by polyethylene glycol (PEG), abscisic acid (ABA), H₂O₂, and dehydration, while being slightly induced by high salinity and cold treatment. The OsMYB48-1 protein was localized in the nucleus with transactivation activity at the C terminus. Overexpression of <i>OsMYB48-1</i> in rice significantly improved tolerance to simulated drought and salinity stresses caused by mannitol, PEG, and NaCl, respectively, and drought stress was caused by drying the soil. In contrast to wild type plants, the overexpression lines exhibited reduced rate of water loss, lower malondialdehyde (MDA) content and higher proline content under stress conditions. Moreover, overexpression plants were hypersensitive to ABA at both germination and post-germination stages and accumulated more endogenous ABA under drought stress conditions. Further studies demonstrated that overexpression of <i>OsMYB48-1</i> could regulate the expression of some ABA biosynthesis genes (<i>OsNCED4</i>, <i>OsNCED5</i>), early signaling genes (<i>OsPP2C68</i>, <i>OSRK1</i>) and late responsive genes (<i>RAB21</i>, <i>OsLEA3</i>, <i>RAB16C</i> and <i>RAB16D</i>) under drought stress conditions. Collectively, these results suggested that <i>OsMYB48-1</i> functions as a novel MYB-related TF which plays a positive role in drought and salinity tolerance by regulating stress-induced ABA synthesis.</p></div

ABA accumulation and the expression of ABA -related genes under drought stress.

<p>(A) ABA contents in normal or drought treated seedlings. Data are means SE (n = 4). (B) qRT-PCR analysis of the expression of ABA biosynthesis genes. (C) Transcript levels of ABA early signaling genes. (D) Transcript levels of ABA later responsive genes under normal or drought stress conditions (withholding water for 5 d). Values are means ± SE (n = 3).</p

ABA hypersensitivity of <i>OsMYB48-1</i> overexpression plants.

<p>(A) Germination performance of <i>OsMYB48-1-</i>overexpression and WT seeds on 1/2 MS medium containing 0, 2, 3, or 5 μM/L ABA measured at 10 d after initiation. (B) Calculation of the germination rates of transgenic and WT seeds. Values are means ± SE (n = 3). (C) Performance of the <i>OsMYB48-1</i> overexpression plants and WT in 1/2 MS medium containing 3 μM/L ABA. (D) The relative shoot length and fresh weight of the transgenic and WT plants grown on normal and ABA-containing medium were compared. SE based on 30 seedlings. Values are means ± SE. * and ** indicate significant difference at P<0.05 and P<0.01 probability, respectively.</p

Expression analysis of the <i>OsMYB48-1</i> gene.

<p>(A) qRT-PCR analysis of the expression level of <i>OsMYB48-1</i> in different tissues of Nipponbare. (B) Expression patterns of <i>OsMYB48-1</i> under various stress treatments including PEG, ABA, H₂O₂, dehydration, NaCl, and cold. Error bars indicate standard error (SE) based on 3 replicates.</p