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Geographical scale might be expected to impact significantly the efficiency of DNA barcoding as spatially comprehensive sampling provides opportunities to uncover intricate relationships among closely related species and to detect cryptic diversity for widespread taxa. Here, we present a DNA barcoding study on a Xencyprididae subfamily (Culterinae) involving the production of 998 newly generated DNA barcodes from East Asian drainages (80 localities). Together with 513 barcodes mined from BOLD and GenBank, a reference library consisting of 1511 DNA barcodes (116 localities) for 42 species was assembled, accounting for 66% of known Culterinae species. Intraspecific genetic distances are positively correlated to geographical scale, while a negative correlation is detected between interspecific genetic distances and geographical scale. The present study demonstrates that geographical scale influences the efficiency of DNA barcoding by narrowing the width of the barcoding gap. DNA-based species delimitation analyses delimited 44 molecular operational taxonomic units (MOTUs). Rampant cryptic diversity is detected within eight species with multiple MOTUs, whereas 25 species present mismatch between morphological and molecular delimitations. A total of 18 species are lumped into nine MOTUs due to low interspecific divergence and/or mixed lineages. Several MOTU divergences are hypothesized to relate to known biogeographical barriers and geological events during the Pliocene and Pleistocene. This study provides new insights into the taxonomy and phylogeography of the subfamily Culterinae.

The grass carp is one of the most important herbivore consumers in aquatic ecosystems and plays key roles in controlling macrophyte abundance. To assess the trophic role of grass carp and their potential grazing pressure on macrophytes in their native range, we quantified their relative abundance (RA), diet composition and trophic niches in two major tributaries and the central delta of the Pearl River using a fish capture survey, high-throughput analysis of the 18S rDNA sequences of their gut contents, and stable isotope analysis. The grass carp RA variation among the sampling regions was explained most by river discharge range. The RA was the highest in the West River with high discharge range, and the lowest in the central delta with low discharge range. The grass carp fed primarily on Streptophyta (relative read abundance: 0.40 ± 0.33) and facultatively on Arthropoda, Rotifera, Ascomycota, and Chlorophyta. The Streptophyta proportion increased from the tributaries to the central delta. Such variation contributed most to the dietary difference among regions. Grass carp belonged to the second trophic level. The position and size of isotopic niche of grass carp differed among regions, and their niche breadth decreased from the tributaries to the central delta, as indicated by the corrected standard ellipse areas (SEAs) and the Bayesian SEAs. The regional differences in hydrological regime and grass carp RA probably affected the macrophyte distribution. The availability of macrophytes likely further contributed to the regional difference in the Streptophyta proportion in grass carp diet.

Although vehicle location-based services are prevalent outdoors, we are back into darkness in many GPS blocked environments, such as tunnels, indoor parking garages, and multilevel flyovers. Existing smartphone-based solutions usually adopt inertial dead reckoning to infer the trajectory, but low-quality inertial sensors in phones are plagued by heavy noises, causing unbounded localization errors through double integrations for movements. In this article, we propose VeTorch , a smartphone inertial odometry that devises an inertial sequence learning framework to track vehicles in real time when GPS signal is not available. Specifically, we transform the inertial dynamics from the phone to the vehicle regardless of the arbitrary phone’s placement in the car and explore a temporal convolutional network to learn the vehicle’s moving dependencies directly from the inertial data. To tackle the heterogeneous smartphone properties and driving habits, we propose a federated learning-based active model training mechanism to produce customized models for individual smartphones, without incurring user privacy issues. We implement a highly efficient prototype and conduct extensive experiments on two large-scale real-world traffic data sets collected by a modern ride-hailing platform. Our results outperform the state-of-the-art vehicular inertial dead-reckoning solutions on both accuracy and efficiency.

Reproductive isolation by time can occur in fish populations composed of individuals with different reproductive schedules. Most studies have tested this phenomenon using mature fish rather than their offspring, which may mask signals of population relationships. We directly sampled fish eggs from artificial fish nests at four different time instances and subsequently fed the eggs to fish larvae in an indoor laboratory. Fish larvae, of each timeline, were randomly selected for species identification using the mitochondrial cytochrome c oxidase I (COI) gene and performed population analyses utilizing the concatenated sequences of COI gene and the mitochondrial control region (D-loop). Neighbor-joining tree and Automatic Barcode Gap Discovery (ABGD) using COI sequences showed that all analyzed larvae can be assigned to the common carp (Cyprinus carpio). Significant differentiation among four demes inferred from the evidence of the concatenated sequences indicated temporal structuring in C. carpio demes within a reproductive season. Haplotype networks and a Bayesian method in BAPS also detected signals of population differentiation among the four demes. The pattern observed in C. carpio demes revealed the reproductive strategy of the species and provided knowledge allowing establishment of conservation units.

Guangdong bream (Megalobrama terminalis) is an economically important species. However, wild Guangdong bream resources have declined sharply in recent years as a result of human disturbance and habitat destruction. Thus, it is crucial that the current resources of Guangdong bream are protected. In this study, 30 novel single nucleotide polymorphism (SNP) markers were developed based on restriction site-associated DNA sequencing (RAD-seq). The results showed that the minor allele frequency varied from 0.021 to 0.489 and that the observed heterozygosity (Ho) and expected heterozygosity (He) ranged from 0.043 to 0.638 and 0.042 to 0.506, respectively. The PIC ranged from 0.041 to 0.375. Seven loci showed significant deviations from the HWE after Bonferroni correction (p

Silver carp (Hypophthalmichthys molitrix) is a world-wide species and its ecosystem level influence is controversial. Therefore, understanding the feeding behaviour of silver carp is important for assessing ecosystem functioning in many freshwater habitats. In this study, we used 18S rRNA sequencing to identify the spatiotemporal taxonomic composition of water and fish gut samples. Significant seasonal and spatial variations were observed in the taxonomic compositions of water and fish gut samples (p < 0.05). Five selected environmental factors (temperature, total phosphorus, chlorophyll a, ammonia, and distance from the first dam downstream) significantly affected the taxonomic composition of water (p < 0.05). Additionally, the temperature was the most important factor affecting seasonal (winter and summer) variations in the prey community composition of water, whereas the distance from the dam was the key factor contributing to spatial differences in the community. Significant differences were observed in the taxonomic composition between the water and fish gut samples (p < 0.05). Feeding selectivity analysis revealed that the selection ratios of the top 20 prey taxa underwent slight spatial and temporal changes, but silver carp always preferred to feed on Peridiniales, unidentified Streptophyta, unidentified Trebouxiophyceae, and unidentified Chlorophyceae. These results indicate that changes in the prey community in the environment affect the taxonomic composition of the fish gut but do not affect feeding preferences.

Objective. The increase of BMI before pregnancy and during pregnancy will lead to hypertensive disorder in pregnancy (HDP) and abnormal glycolipid metabolism, as well as increase the risk of neonatal weight abnormalities and adverse pregnancy outcome. This study retrospectively analyzed the clinical data of 358 women who were admitted to the obstetrics department of our hospital from January 2018 to July 2019. And the relationship between prepregnancy BMI, BMI increase during pregnancy and delivery methods, postpartum hemorrhage, neonatal weight, premature delivery, neonatal asphyxia, gestational diabetes mellitus (GDM), and hypertension during pregnancy (HDP) was observed and compared. The results show that both high BMI before pregnancy and excessive weight gain during pregnancy can lead to the incidence of abnormal birth weight and adverse birth outcome increase. Therefore, in order to reduce the incidence of neonatal weight abnormalities and adverse birth outcomes and to prevent the adverse effects during pregnancy and postpartum, clinically, obese women should be guided to eat according to reasonable diet and exercise to control their weight.

Although non‐native species can modify ecosystem function, their effects in southern China have not been investigated, despite their ecological importance. This study assessed how Nile tilapia Oreochromis niloticus (L.) invasions impact the functional patterns of fish communities in the large subtropical Pearl River by analysing the relationships between invasion and body size over a 9‐year period. The relative abundance of Nile tilapia increased significantly over time. In particular, the established Nile tilapia significantly undermined the relative densities and the body size of the native fishes. Importantly, this study provided empirical evidence that functional indices (such as body size) are more sensitive when evaluating the effects of non‐native species on a community than richness. Understanding processes such as those should be the basis of controlling alien fish species and fisheries management in the Pearl River.

Individual specialization and high plasticity in feeding activity are common in natural populations. However, the role of these two in intraspecific competition is unclear. In this study, the rhythm of feeding activity, dietary composition, niche width, niche overlap, and individual specialization was explored in four different size groups of black amur bream (Megalobrama terminalis), using microscopic identification of foregut contents and stable isotope analysis (δ13C and δ15N) of dorsal muscle. Both methods observed ontogenetic shifts in dietary preference and individual specializations, and revealed that the total niche width of large individuals was greater than small individuals. Mixed linear models indicated that feeding activity was significantly influenced by time (p p = 0.244). Niche overlaps revealed that there was intensive diet competition between different size groups of black amur bream. Individual specialization in small juveniles was likely to be stronger than sub-adult and adult groups. Pearson’s correlation analysis revealed that the individual specialization was positively correlated with mean diet similarity within a group. The results indicated that intraspecific competition is reduced mainly by individual dietary specialization, rather than shift in feeding activity.

Resolving the temporal community composition of a larvae population can not only further our understanding of the regional species composition but also help us to infer the reproductive times of regional fish taxa, which can have implications on the development of effective monitoring and conservation policies for the regional fish stock. Nevertheless, correctly diagnosing the fish larvae is extremely challenging due to the paucity of diagnostic morphological characters at the species level. Based on daily larval samplings during March and October in 2018, this study combined morphological features with a DNA barcode technique to determine the species composition of fish larvae in the lower Pearl River drainage (LPR) and evaluate the spawning periods of identified species. Due to an absence of reference barcodes for LPR fishes, a DNA barcode library of adult fishes in the LPR was built for 384 individuals representing 78 morphological species. Analyses demonstrated the usability of the barcode library and uncovered many undetected mitochondrial lineages in 12 species. Morphological analyses performed on 81 temporal larval samples revealed 25 morphotypes and assigned 9 morphotypes into the species level. A total of 1624 larvae from 96 temporal larval samples were selected for molecular identification, and high quality barcoding sequences were obtained from 1391 larvae. We accurately assigned 1078 larvae to 37 species using our barcode library and published database. Among the identified species, a critically endangered species, namely, Ochetobius elongatus, and several invasive species were examined, providing a new perspective to assess the stock of regional endangered and invasive species. Furthermore, this study found high species diversity occurred primarily between May and September, and clarified the spawning periods of identified species inferred from the temporal occurrences of larvae. Above all, our study highlights the applicability to fish larval ecology to assist conservation and fishery management efforts.

Understanding fish migration patterns and habitat use is essential for fisheries management. We conducted an acoustic fine-scale tracking experiment from March to June 2017 to determine the common carp movement pattern and habitat use in the downstream area of the Pearl River. The eight tagged common carp were detected for 39.38 &plusmn, 29.57 d, on average, with a total average detection period of 42.12 &plusmn, 28.02 d. A general linear mixed model suggested they were detected more during the night than during the day. Common carp preferred habitats near the sandbar and riparian shallow habitats, as revealed by their movement tracks and habitat selection indexes. The general additive mixed model (GAMM) analysis of their shortest distances to riverbanks and depth indicated that they migrated to shallower riparian habitat more frequently during the night than during the day. The continuous wavelet spectrum further confirmed the significant diel pattern of their vertical movement. Their habitat use was also influenced by the water temperature, water level, and river discharge, as suggested by the GAMM. Our results provide novel information on common carp spatiotemporal movement and habitat use patterns, and have important implications for its native population restoration and the invasive population control/exclusion.

The grass carp Ctenopharyngodon idella is a commercially relevant carp species with a long-term artificial release history in China. To date, several genetic diversity studies have been performed on the Yangtze River C. idella populations, but similar reports were sparse for the Pearl River populations. Here, our study explored the genetic diversity patterns and population structure of the Pearl River C. idella populations after human intervention using two mitochondrial loci. Phylogenetic analyses demonstrated that grass carp populations in the Pearl River exhibited two maternal genetic lineages. Haplotype networks demonstrated that most main Pearl River haplotypes were shared with those of the Yangtze River samples. No genetic structure was detected among the Pearl populations and low level of population differentiation was observed between individual Yangtze River populations and the Pearl River populations. These findings might be attributed to the high dispersal ability of grass carp, as well as anthropogenic release. Moreover, the nucleotide diversity of the Pearl River populations was higher than that of the Yangtze River, indicating that artificial release programs might have significant effects on the genetic diversity of the Pearl River populations. Taken together, our findings demonstrated artificial release programs may have influenced the Pearl River grass carp populations and provide important knowledge that may guide the future management of grass carp in the Pearl River.

Ochetobius elongatus (Cyprinidae, Leuciscinae) was once an endemic species and widely distributed in numbers of rivers throughout South China. Nevertheless, the wild population of O. elongatus reduced dramatically in recent years due to anthropogenic impacts and it has been listed as a critically endangered species by IUCN. In this study, 26 novel single nucleotide polymorphism (SNP) markers were developed based on Restriction-site associated DNA sequencing. The results showed that the minor allele frequency varied from 0.071 to 0.500, the observed heterozygosity and expected heterozygosity ranged from 0.093 to 0.964 and 0.133 to 0.505, respectively. The PIC ranged from 0.124 to 0.375. Six loci showed significant deviations from the HWE after Bonferroni correction (p

Herein, we propose a novel Ti3C2 grafted SiO2 (Ti3C2-g-SiO2, 21.2% loading weight content of SiO2) multifunctional filler with an average thickness of 10 ± 2 nm, which is skillfully prepared via an in-situ growing approach, to blend with styrene-butadiene rubber (SBR) and create high-performance elastomer composites. Thanks to the incorporation of SiO2, the Ti3C2-g-SiO2 not only disperses better (a uniform state) than Ti3C2 in the rubber matrix but also obtains innumerous nano protuberances on its surface to constrain more rubber chains than Ti3C2, significantly improving the interfacial interaction. Therefore, by comparison of the unfilled SBR sample, the mechanical strengths of the prepared Ti3C2-g-SiO2 filled SBR sample are dramatically enhanced, including tensile strength (enhanced by 244%, from 4.09 to 14.1 MPa) and elongation at break (enhanced by 93%, from 271 to 522%). More importantly, the Ti 3C2-g-SiO2 filled SBR sample featuring excellent electrical (8.96 × 10−4 S m−1 ) and thermal conductivities (0.449 W m −1 k−1 ), which could exceed the reduced graphene oxide filled SBR sample.

In this study, a single-layered Ti3C2 hybrid SiO2 filler (Ti3C2-h-SiO2) was proposed to fabricate high-performance styrene-butadiene rubber (SBR) elastomer composites. It was found that incorporating SiO2 not only facilitated the uniform dispersion of Ti3C2-h-SiO2 in the SBR matrix but also endowed the surface of Ti3C2-h-SiO2 with nano protuberances for immobilizing more rubber chains, resulting in the improvement of the interfacial interaction between Ti3C2-h-SiO2 and SBR matrix. Thus, the tensile strength of the SBR/Ti3C2-h-SiO2 elastomer composite was reinforced by 174% compared with the unfilled SBR. Moreover, the wet skid resistance and rolling resistance of the SBR/Ti3C2-h-SiO2 elastomer composite were also remarkably improved. Noteworthily, the exceptional thermal conductivity (0.401 W m−1 k−1) and electrical conductivity (4.87 × 10−4 S m−1) of the SBR/Ti3C2-h-SiO2 elastomer composite were comparable to the SBR/reduced graphene oxide (rGO) elastomer composite, implying that the conductivity of Ti3C2-h-SiO2 may be competitive with the rGO.

Black Amur bream (Megalobrama terminalis) is an economically important indigenous species that dominates the fish community in the lower reaches of the Pearl river. We used small subunit ribosomal DNA (18S rDNA) sequencing to assess the intestinal contents of black Amur bream at four independent developmental stages (stages II, III, IV, and V). This represents a new approach to the analysis of fish diets in the field. The results showed that Eunicida, Tubificina, unclassified Demospongiae, unclassified Insecta, unclassified Hexactinellida, unclassified Bivalvia and Monogononta constitute the predominant primary food sources of black Amur bream. Interestingly, a shift in the diet of black Amur bream was observed upon the fish reaching a standard length of around 225 ± 19.3 mm during gonad development from stage III to IV. A reduction in the consumption of Demospongiae and Rotifera, and an increase in the consumption of Annelida (mostly Eunicida) and Tubificina, were observed. Stage III in the developmental process is a transition phase in relation to dietary shift, which exhibits the food preferences both of juveniles and adults. We also observed that food items that were detected in the foregut were also present in the hindgut, indicating that 18S rDNA amplification of fecal matter could be used for dietary analysis in fish in the field.

Gene expression is generally regulated by multiple transcription factors (TFs). Despite previous findings of individual TFs regulating pancreatic α-amylase gene expression, the combinatorial transcriptional regulation is not fully understood. To gain insight into multiple TF regulation for pancreatic α-amylase gene, we employed a function conservation approach to predict interacting TFs regulating pancreatic α-amylase gene for 3 dietary animal groups. To this end, we have identified 77, 25, and 118 interacting TFs for herbivore, omnivore, and carnivore, respectively. Computational modeling of TF regulatory networks demonstrated that known pancreas-specific TFs (e.g. GR, NFAT, and PR) may play important roles in recruiting non pancreas-specific TFs to the TF-TF interaction networks, offering specificity and flexibility for controlling pancreatic α-amylase gene expression in different dietary animal groups. The findings from this study indicate that combinatorial transcriptional regulation could be a critical component controlling pancreatic α-amylase gene expression.

This study aimed to determine the age, growth, mortality, and population structure of the economically important cyprinid silver carp Hypophthalmichthys molitrix (Valenciennes, 1844) in the middle and lower reaches of the Pearl River. A total of 297 silver carp were sampled quarterly from the catches of gillnet fishermen, at six sites, between June 2019 and September 2020. Standard length of the specimens ranged from 130 to 585 mm, and body weight ranged from 45.5 to 3930 g. The length–weight relationship parameter b values reached 3.015. Age was determined through examination and measurements of fish scales, and the age composition of the sampled silver carp varied from 0+ to 4+. Fitting the new data to the von Bertalanffy growth model, we obtained an asymptotic size (L∞) of 1107 mm, k of 0.135, and t0 of −0.666 for silver carp in this stretch of the river. The calculated growth performance index ϕ and estimated longevity tmax were 5.22 and 21.56, respectively. The rates of total mortality, natural mortality, and fishing mortality were calculated as 0.4997, 0.1621, and 0.3377, respectively, while the exploitation ratio was evaluated as 0.6757. The overall results confirm overexploitation of this resource in the middle and lower reaches of the Pearl River. It was concluded that this species should be protected from capture until at least 790 mm in standard length, representing an optimal minimum size for capture to benefit conservation of the species and to sustainably develop this valuable fishery.

In this study, the complete mitochondrial genome of Carassioides acuminatus was first sequenced and annotated. The entire mitogenome is 16,579bp in length, which consists of 13 protein-coding genes (PCGs), 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region (D-loop). The overall nucleotide composition of the C. acuminatus mitochondrial genome shows an obvious anti-G bias. The accuracy of the fresh sequences was verified by phylogenetic analysis. The complete mitochondrial genome of C. acuminatus is useful to population genetics and molecular systematics.

Commercial ethylene propylene diene monomer (EPDM) rubber grafted with maleic anhydride (EPDM-g-MA) was thermoreversibly crosslinked by silane modified silica. EPDM-g-MA was first modified with furfurylamine to obtain furan functionalized EPDM (EPDM-g-FA) which was then crosslinked with 3-methacryloxypropyltrimethoxysilane (as electron-poor agent) modified silica via a Diels-Alder reaction. The as-formed rubber network could be broken at high temperature and reconstructed by thermal annealing, which were proven by differential scanning calorimetric analysis and solubility testing. The mechanical strength of the resulting EPDM/silica composites could be tailored by the amount of modified silica and were superior to the previously reported EPDM rubber crosslinked by low molecular organic agents. More importantly, the rubber composites showed good thermal reprocessability and self-healing behavior, by which the crosslinked composites could be recycled to use with comparable mechanical property as the original composites.

Summary Length–weight relationships (LWRs) were estimated for 15 species belonging to four orders and five families from the Xunjiang River, China. Exponent b varied from 2.364 to 3.634, and r2 values varied from .914 to .991. This is the first LWR report in the area for these species, seven species of which are published for the first time.

Summary Length–weight relationships (LWRs) were determined for seven fish species collected during 2014 and 2015 between January and July each year from Nandujiang River. The study used drift gillnet with 4 cm mesh (100 m long × 1.2 m high) as well as electrofishing. The parameter “b” of the LWR equations varied between 2.963 to 3.171 for the species studied.

Cirrhinus molitorella is one of the most important commercial fish species in the Pearl River, but there are few published studies on the early growth of this species. In the present study, seasonal recruitment patterns, temporal variations in early growth rates and environmental variables were analysed. In all, 1512 individuals were collected during monthly sampling from July 2015 to January 2016, ranging from 30.8- to 84.9-mm standard length (SL). A subsample of 276 juveniles was aged from 68 to 193 days, with hatch dates between 2 February and 19 September, by determining daily increments in otoliths. Monthly abundance data and SL frequency distributions showed that there were two major temporal cohorts of juvenile recruitment, which hatched primarily in April and July. Average growth rate, estimated by the linear relationship between age and SL, was greater for the April cohort (0.49mmday–1) than the July cohort (0.37mmday–1). Mean increment widths from the 23rd increment onwards were significantly greater for the April than July cohort (P

Summary Fish assemblages were randomly collected in March 2015 from the upper reaches of the Beijiang River, Shaoguan, China. Fish were sampled on 10 occasions using gill nets (mesh size: 3 cm) and the length–weight relationships (LWRs; W = a × Lb) of three native species recorded: Xenocypris davidi, Xenocypris macrolepis and Culter recurviceps. The exponent b varied from 2.803 to 3.096 and r2 values ranged 0.985–0.992. This is the first report on the LWRs of fish from this area, with valuable results for the research, management and conservation of fishery resources in the upper reaches of the Beijiang River.

Epithelial-mesenchymal transition (EMT) plays an important role in cancer invasion and metastasis by enabling cancer cells to depart from the primary tumor, invade surrounding tissue and disseminate to distant organs. The existence and function of EMT in cervical cancer is poorly understood. Placental growth factor (PLGF) has been shown to associate with EMT in various cancers. However, whether PLGF is involved in EMT in cervical cancer remains unclear. Thus the present study examined the relationship between PLGF expression and EMT-related proteins in 110 cervical lesions samples. We detected that PLGF was expressed in 61.8% cervical lesion sections. In addition, PLGF expression is positively correlated with low expression level of E-cadherin and high expression level of vimentin. Serum samples and cervical lavage samples were collected from patients with pre-invasive and invasive lesion of uterine cervix or normal control group, the PLGF levels were determined by enzyme-linked immunosorbent assay (ELISA). We found that a significantly high level of PLGF could be detected both in serum and vaginal lavage compared with normal women group, and there is no significant difference between serum and lavage in PLGF level. In addition, whatever in lavage or in serum, the PLGF level in stage I and II was significantly higher than it in CINIII or cancer in situ. However, there is no significant difference between the stage I and stage II; we also found that exogenous PLGF promotes molecular changes of epithelial-mesenchymal transition (EMT) in siha cells. In addition, application of a specific EKR1/2 inhibitor could reverse the effects of PLGF. These findings suggested that PLGF could regulate the expression of EMT-related proteins and promote migration of siha cells through ERK/MAPK signaling pathway. Therapies that targets PLGF/Flt-1/ERK/MAPK signaling pathway may be beneficial in treatment of cervical cancer.