Heavy metal contamination in duck eggs from a mercury mining area, southwestern China.

Objective: Mercury (Hg) contamination in the environment around mercury mines is often accompanied by heavy metal contamination. Methods: Here, we determined concentrations of chromium (Cr), zinc (Zn), strontium (Sr), barium (Ba), and lead (Pb) in duck eggs from a Hg mining area in Southwest China to assess the contamination and health risk. Results: Duck eggs obtained from the mining area exhibit higher concentrations of Cr, Zn, Sr, Ba, and Pb compared to those from the background area, with egg yolks containing higher metal levels than egg whites. Specifically, the mean Cr, Zn, Sr, Ba, and Pb concentrations of duck eggs from the Hg mining area are 0.38, 63.06, 4.86, 10.08, and 0.05 µg/g, respectively, while those from the background area are only 0.21, 24.65, 1.43, 1.05, and 0.01 µg/g. Based on the single-factor contamination index and health risk assessment, heavy metal contamination in duck eggs poses an ecological risk and health risk. Conclusion: This study provides important insight into heavy metal contamination in duck eggs from Hg mining areas.

Metabolisms of both inorganic and methyl-mercury in hens reveal eggs as an effective bioindicator for environmental Hg pollution.

Mercury (Hg) is a globally distributed toxic metal and could pose serious harm to birds, which may ultimately threaten human health through poultry consumption. However, the avian Hg metabolism remains unclear. Poultry, like chickens, are more accessible human dietary sources than wild birds and are ideal proxies to study Hg metabolism in birds. In this study, the avian Hg metabolism is carefully investigated with hens fed by Hg-spiked (both inorganic mercury IHg and methylmercury MeHg) foods. Our results demonstrate that feces and eggs are the main removal pathways of Hg from hens, rather than feathers. Eggs show particularly rapid responses towards Hg exposures, thus could be more sensitive to environmental Hg pollution than feathers, feces or internal organs (and tissues). Egg yolk (with THg peak of 55.92 ng/g on Day 6) and egg white (THg peak of 1195.03 ng/g on Day 4) react as an effective bioindicator for IHg and MeHg exposure, respectively. In 90-day-single-dose exposure, IHg is almost completely excreted, while approximately 11% of MeHg remains in internal organs. Our study provides new insight into the metabolism and lifetime of IHg and MeHg in birds, advancing the understanding of the dynamics for human exposure to Hg through poultry products.

Buffer zone-based trace elements indicating the impact of human activities on karst urban groundwater.

The tanglesome allocation of landscape types at various spatial dimensions is an important component influencing the quality of groundwater environment in karst cities. Trace elements can be used as indicators of the extent of impact on groundwater which is an effective means of tracing groundwater contamination. In this study, we studied the influence of landscape patterns on trace elements in groundwater of typical karst cities in Southwest China (Guiyang City) on a multi-spatial scale by using multivariate statistical analysis. According to the sampling points, buffer zone scales with different radii (500 m, 1000 m, 1500 m, and 4000 m) were established to quantify the land use model. There are suburban and urban differences in trace element content. The city center has higher levels of trace elements compared to suburban areas, especially Li, Ni, Tl, Cu, Sr, Co, As, and Mn. In addition, the outcomes of the multiple linear regression had shown that the size effect of the association from landscape pattern to trace elements varies with different indicators and parameters. The results of redundancy analysis showed an overall change in trace elements was better interpreted by the landscape pattern of the 1500 m-scale buffer. At the same time, at the 1500 m scale, Ni, Tl, Cu, Co, As, Cr, Sr, Li, and Mn were positively correlated with the urban landscape index (4LPI, 4LSI), influenced by urban anthropogenic activities, while Cd, Zn, and Pb were positively correlated with the cropland landscape index (1AI, 1LPI), influenced by agricultural activities. This study indicates that trace elements are a reliable indicator for tracing groundwater contamination. The buffer zone can reflect the extent of urban impacts on groundwater and provide a new and effective analytical tool for groundwater management.

Total mercury in different egg tissues provides insights to mercury metabolisms in bird bodies.

Mercury (Hg) pollution in birds has been widely reported, but the metabolism of Hg in bird bodies remains unclear. Measurement of Hg concentrations in bird tissues (muscles and organs) could provide insights into the metabolism of Hg in bird bodies, however, this approach is often invasive. To avoid invasive procedures, we conducted feeding experiments using chickens and used eggs as a proxy for understanding Hg metabolism in chicken bodies. For the control group, various THg concentrations were observed in egg whites, egg yolks, and eggshells, but the THg concentration trends for different egg tissues were not statistically different (P > 0.05). For the Hg feeding group (0.3 mg/kg body weight, feeding once), Hg peaks were observed in egg yolks and egg whites at different time periods, suggesting different response time to dietary Hg in chicken body tissues. Mercury in egg yolks peaked at Day 6, suggesting their quick response to dietary Hg. Egg whites reached Hg peak at Day 20, exhibiting a slower response to dietary Hg. Eggshells did not show a Hg peak, perhaps due to their predominant inorganic components that do not trigger Hg bioaccumulation. We measured THgyolk/THgwhite ratios in various chicken eggs purchased from three areas in Guizhou, SW China. The THgyolk/THgwhite ratios for Huaxi, Hezhang and Wuchuan were 1.33 (0.57-2.41), 7.89 (4.27-19.47) and 2.64 (1.68-4.22), respectively, to suggest different exposure history for chickens. This study provides new insights into the metabolism and lifetime of Hg in bird bodies.

Coupled controls of the infiltration of rivers, urban activities and carbonate on trace elements in a karst groundwater system from Guiyang, Southwest China.

Hydrogeochemical processes of trace elements (TEs) are of considerable significance to river water and groundwater resource assessment and utilization in the karst region. Therefore, seven TEs were analyzed to investigate their contents, spatial variations, sources, and controlling factors in Guiyang, a typical karst urban area in southwest China. The results showed that the average content of TEs in river water (e.g., As = 1.44 ± 0.47 µg/L andCo = 0.15 ± 0.06 µg/L) was higher than that of groundwater (e.g., As = 0.51 ± 0.42 µg/L andCo = 0.09 ± 0.05 µg/L). The types of groundwater samples were dominated by Ca/Mg-HCO3 and Ca/Mg-Cl types, while those of the river water samples were Ca-Cl and Ca/Mg-Cl types. Principal component analysis (PCA) and correlation analysis (CA) analyses indicated that As and Mn in the groundwater of the study area were related to river infiltration. The end-member analysis further revealed that river infiltration (As = 0.86-1.81 µg/L, Cl/SO42- = 0.62-0.89) and urban activities (As = 0.21-0.32 µg/L, Cl/SO42- = 0.51-0.89) were two main controlling factors of TEs (e.g., As, Co, and Mn) in the study area. In addition, the ion ratios in river and groundwater samples indicated that the weathering of carbonates was also an important control on the hydrogeochemistry of TEs (e.g., Fe and Mn) in Guiyang waters. This study showed that the trace element (TE) contents of groundwater in the Guiyang area were greatly associated with urban input and river recharge, and provided a new perspective for understanding the geochemical behavior of TEs in urban surface and groundwater bodies, which will help the protection of groundwater in the karst areas of southwest China.

Anthropogenic rare earth elements in urban lakes: Their spatial distributions and tracing application.

Anthropogenic activities associated with various new technologies are increasingly disrupting the geochemical cycles of rare earth elements (REEs). For example, samarium (Sm) and gadolinium (Gd) have emerged as microcontaminants in the natural waters of developed areas. Surface water samples of 13 urban lakes were collected in Wuhan, the largest city in central China, with a population of over 11 million. The aim of this study was to examine to what extent REE anomalies occur and the relationship between the concentration of anthropogenic REEs in lakes and the surrounding environment. In this study, based on land-use type and point of interest (POIs) data, buffer extraction, density estimation and Spearman correlation analysis were first proposed to identify different sources of anthropogenic REEs, which mainly included hospitals, factories, population, urban land and cropland. The PAAS-normalized REE patterns indicate that all lake samples display pronounced positive Sm and Gd anomalies, ranging from 5.92 to 19.88 and 1.73 to 14.97, respectively. Spearman correlation analysis showed that hospital density was positively correlated with anthropogenic Gd concentration, and a positive relationship between proportion of cropland and the concentration of anthropogenic Sm. By utilizing Gdanth, Smanth, and the conventional ion ratio (NO3-/Cl-), a three-dimensional tracer system was established, and the system accurately obtained a characterization of the impact of WWTPs, hospitals, factories and agriculture on the lakes. Moreover, the results from this hydrochemical method were consistent with the analysis of geographic information systems, which indicated that this anthropogenic contaminant as a tracer was reliable for analysing the source of urban water pollution.

Distribution, source, water quality and health risk assessment of dissolved heavy metals in major rivers in Wuhan, China.

Heavy metals are released into the water system through various natural processes and anthropogenic activities, thus indirectly or directly endangering human health. The distribution, source, water quality and health risk assessment of dissolved heavy metals (V, Mn, Fe, Co, Ni, Zn, As, Mo, Sb) in major rivers in Wuhan were analyzed by correlation analysis (CA), principal component analysis (PCA), heavy metal pollution index (HPI), hazard index (HI) and carcinogenic risk (CR). The results showed that the spatial variability of heavy metal contents was pronounced. PCA and CA results indicated that natural sources controlled Mn, Fe, Co, Ni and Mo, and industrial emissions were the dominant factor for V, Zn and Sb, while As was mainly from the mixed input of urban and agricultural activities. According to the heavy metal pollution index (HPI, ranging from 23.74 to 184.0) analysis, it should be noted that As and Sb contribute most of the HPI values. The health risk assessment using HI and CR showed that V and Sb might have a potential non-carcinogenic risk and As might have a potential carcinogenic risk to adults and children in the study area (CR value exceeded target risk 10-4). At the same time, it was worth noting that As might have a potential non-carcinogenic risk for children around QLR (HI value exceeded the threshold value 1). The secular variation of As and Sb should be monitor in high-risk areas. The results of this study can provide important data for improving water resources management efficiency and heavy metal pollution prevention in Wuhan.

Bombyx mori Nucleopolyhedrovirus p26 Is Associated with Viral Late Stage Replication.

Bombyx mori nucleopolyhedrovirus (BmNPV) p26 is conserved among all Lepidoptera baculoviruses that have been completely sequenced thus far, and some baculoviruses even have two copies of p26, which suggested that p26 may play an important role in the virus infection cycle. This study aimed to characterize BmNPV p26. We found that BmNPV p26 transcripts were detectable as early as 3 h post-infection (hpi), and the transcript levels rapidly increased starting from 12 hpi. Western blot analysis using an anti-p26 polyclonal antibody demonstrated that the corresponding protein was also detectable from 6 hpi in BmNPV-infected cell lysates. Immunofluorescence analysis demonstrated that p26 was mainly dispersed in the infected cell cytoplasm, whereas the over-expressed fusion protein EGFP-p26 also accumulated in the nucleus. These results indicated that p26 is an early BmNPV gene and has functions both in the cytoplasm and the nucleus. RNAi-based knockdown of p26 could produce infectious virus and normal-appearing virions but decreased budded virus (BV) production in BmNPV-infected cells at 72 hpi. Moreover, the results of further quantitative PCR (Q-PCR) analysis indicated that the gp64 and p74 transcripts levels decreased significantly. These results indicated that BmNPV p26 may be associated with BmNPV replication during the late infection stage.

The Pupal Pigmentation Pattern and Pupal Development in the Species of Aphytis Howard (Hymenoptera: Aphelinidae).

Species identification of Aphytis on the basis of adult morphology is extremely difficult, especially in the A. lingnanensis group, with several cryptic species. Pupal pigmentation could be used as one of the taxonomic characters for Aphytis species, and in some instances, pupal pigmentation actually provided the first clue to the distinctness of cryptic Aphytis species. The present study investigated the full-grown larvae or younger pupae of Aphytis species, and pupal pigmentation and pupal development were observed and photographed. Four characteristic pigmentation patterns of Aphytis pupae were summarized including: entirely yellow, partly dark brown, entirely or predominantly black, and partly black. The species in the chilensis and mytilaspidis groups, and some unassigned species, generally have entirely, or predominantly and or partly black pupae. The species in the chrysomphali, funicularis, and proclia groups generally have the pupae entirely yellow. The species of the lingnanensis group have the pupae both entirely yellow, e.g., A. fisheri, and partly dark brown pupae, e.g., A. lingnanensis, A. holoxanthus and A. melinus. The pupae of Aphytis species in this study had a developmental duration of about 5-8 days at 27 ± 1 °C, 70 ± 5% RH and a photoperiod of 10L: 14D. It was found that the pupal skin was always melanized at the beginning stage, generally in the first day, among the pigmented pupae of Aphytis species. As development continued, the pigmentation became darker and the eye colour changed from pale red/brown to green. No significant intra-specific variation in pupal colour pattern was detected despite relatively high numbers of specimens examined, many from multiple, and different, origins. Overall, our study indicates that pupal pigmentation could be more helpful in species identification of Aphytis.

Evaluation of the effects of Hg/DOC ratios on the reduction of Hg(II) in lake water.

Reduction of mercury (Hg) in natural waters, which releases a substantial amount of gaseous Hg(0) to the atmosphere, has a close relationship to Hg/DOC ratios. However, the role of Hg/DOC ratio on the Hg(II) reduction in natural waters remains poorly understood. In this study, natural water collected from Hongfeng Lake, SW China, was used to study the effects of Hg/DOC ratio on the Hg(II) reduction. The lake water was spiked with variable amounts of Hg to make different Hg/DOC solutions. Through a 72 h Hg(II) reduction process, we demonstrated that the maximum percentage reduction of Hg (29 ± 3%) occurred when Hg/DOC ratio was 1134 ng mg-1. Further increase or decrease of the Hg/DOC ratios would inhibit the reduction of Hg(II). This study clearly demonstrated that Hg/DOC ratio has a dual role in the reduction of Hg(II) from natural waters.

Long non-coding RNA TUG1 promotes cell progression in hepatocellular carcinoma via regulating miR-216b-5p/DLX2 axis.

BACKGROUND: Accumulating evidence indicates that the long noncoding RNA taurine upregulated gene 1(TUG1) plays a critical role in cancer progression and metastasis. However, the overall biological role and clinical significance of TUG1 in hepatocellular carcinoma (HCC) remain largely unknown. METHODS: The expressions of TUG1, microRNA-216b-5p and distal-less homeobox 2 (DLX2) were detected by Quantitative real-time polymerase chain reaction (qRT-PCR). The target relationships were predicted by StarBase v.2.0 or TargetScan and confirmed by dual-luciferase reporter assay. The cell growth, apoptosis, migration and invasion were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Flow cytometry and Transwell assays, respectively. All protein expression levels were detected by western blot. Tumor xenografts were implemented to explore the role of TUG1 in vivo. RESULTS: We found that there was a marked rise in TUG1 expression in HCC tissues and cells, and knockdown of TUG1 repressed the growth and metastasis and promoted apoptosis of HCC cells. In particular, TUG1 could act as a ceRNA, effectively becoming a sink for miR-216b-5p to fortify the expression of DLX2. Additionally, repression of TUG1 impared the progression of HCC cells by inhibiting DLX2 expression via sponging miR-216b-5p in vitro. More importantly, TUG1 knockdown inhibited HCC tumor growth in vivo through upregulating miR-216b-5p via inactivation of the DLX2. CONCLUSION: TUG1 interacting with miR-216b-5p contributed to proliferation, metastasis, tumorigenesis and retarded apoptosis by activation of DLX2 in HCC.

Anthropogenic Rare Earth Elements: Gadolinium in a Small Catchment in Guizhou Province, Southwest China.

Rare earth elements (REEs), known as "industrial vitamins", are widely used in medical treatment, industry, agriculture, etc. However, with the increasing demand for REEs, excess REEs, such as gadolinium (Gd), are considered micropollutants in the environment. In this paper, the distributions of dissolved REEs were analyzed in three small streams, in order to determine the extent and occurrence of Gd anomalies. The shale-normalized REE patterns in the three streams were less smooth with heavy REEs higher than light REEs, for a weak reaction of the heavy REE complexes. A negative Ce (cerium) anomaly and positive samarium (Sm) and europium (Eu) anomalies were observed in the three streams and the negative Ce anomaly was affected by the pH of the alkaline rivers. However, a positive Gd anomaly was found in only a typical urban small stream, Jinzhong. With a population of approximately 60,000, Jinzhong runs by a hospital and through wastewater treatment plants (WWTPs). The concentrations of Gd in Jinzhong ranged from 1.54 to 86.65 ng/L with high anthropogenic Gd proportions (63.64%-98.07%). Anthropogenic Gd showed significant seasonal variations and distinct spatial disparities from upstream to downstream, and it was associated with certain ions such as Cl-. Anthropogenic Gd could be attributed to gadopentetic acid (Gd-DTPA), which is used in magnetic resonance imaging (MRI) in hospitals. This type of Gd was shown to be correlated with municipal wastewater. Due to the high stability and low particulate reactivity in water, anthropogenic Gd has great potential to serve as a tracer to prove the presence of medical wastewater.

TiO2 Nanotubes/Ag/MoS2 Meshy Photoelectrode with Excellent Photoelectrocatalytic Degradation Activity for Tetracycline Hydrochloride.

A novel type of TiO2 nanotubes (NTs)/Ag/MoS2 meshy photoelectrode was fabricated with highly oriented TiO2 nanotube arrays grown from a Ti mesh supporting Ag nanoparticles and three-dimensional MoS2 nanosheets. In this structure, Ag nanoparticles act as bridges to connect MoS2 and TiO2 and pathways for electron transfer, ensuring the abundant production of active electrons, which are the source of •O2-. The TiO2 NTs/Ag/MoS2 mesh can be used as both photocatalyst and electrode, exhibiting enhanced photoelectrocatalytic efficiency in degrading tetracycline hydrochloride under visible light irradiation (λ ≥ 420 nm). Compared to unmodified TiO2 NTs, the improved photoelectrocatalytic activity of the TiO2 NTs/Ag/MoS2 arise from the formation of Z-scheme heterojunctions, which facilitate the efficient separation of photogenerated electron-hole pairs through the Schottky barriers at the interfaces of TiO2 NTs⁻Ag and Ag⁻MoS2.

An insect nucleoside diphosphate kinase (NDK) functions as an effector protein in wheat - Hessian fly interactions.

Like pathogens, galling insects deliver effectors into plant tissues that induce gall formation. The gall midge Mayetiola destructor, also called Hessian fly, can convert a whole wheat seedling into a gall by inducing the formation of nutritive cells at the feeding site, inhibiting wheat growth, and reprogramming metabolic pathways of the attacked plants. Here we demonstrated the identification of a secreted Hessian fly protein, the nucleoside diphosphate kinase (NDK), in infested wheat plants through liquid chromatography-tandem mass spectrometry (LC-MS/MS) and western blots. In association with the NDK presence, enzymatic activity of NDK increased significantly in wheat tissues at the feeding site. In addition, there was a sudden increase in ATP abundance at the feeding site of infested susceptible wheat seedlings 24 h following Hessian fly larval infestation. Even though a direct link between cause and effect remains to be established, our data points to the direction that Hessian fly larvae injected NDK into wheat tissues as an effector protein, which plays a role in manipulating host plants and converting the plants into galls.

Cu Isotopic Composition in Surface Environments and in Biological Systems: A Critical Review.

Copper (Cu) is a transition metal and an essential micronutrient for organisms, but also one of the most widespread toxic inorganic contaminants at very high content. The research on Cu isotopes has grown rapidly in the last decade. Hitherto, a large number of studies have been published on the theoretical fractionation mechanisms, experimental data and natural variations of Cu isotopes in variable environments and ecosystems. These studies reported a large variation of δ65Cu (-16.49 to +20.04‰) in terrestrial samples and showed that Cu isotopes could be fractionated by various biogeochemical processes to different extent. Several papers have previously reviewed the coupling of Cu and Zn isotope systematics, and we give here a tentative review of the recent publications only on Cu isotopesin variable surface repositories, animals and human beings, with a goal to attract much attention to research on Cu (and other metals) behaviors in the environment and biological systems.

Two new species of Encarsia Förster (Hymenoptera, Aphelinidae) and first description of the male E. plana Viggiani & Ren from China.

Two new species of Encarsia Förster (Hymenoptera: Aphelinidae) are described from China, Encarsia floralis Wang, Huang & Polaszek, sp. nov. and Encarsia maculiformis Wang, Huang & Polaszek, sp. nov., and the male of Encarsia plana Viggiani & Ren (1987) is newly described.

Three new species of Baeoentedon Girault (Hymenoptera: Eulophidae) from China, with the first record of whitefly host association (Hemiptera: Aleyrodidae).

Three new species of Baeoentedon Girault (Hymenoptera: Eulophidae) are described from China, Baeoentedon balios Wang, Huang & Polaszek sp. nov., Baeoentedon bouceki Wang, Huang & Polaszek sp. nov. and Baeoentedon virgatus Wang, Huang & Polaszek sp. nov. Both female and male of Baeoentedon balios were reared from the whitefly Pealius spina (Singh) (Hemiptera: Aleyrodidae) on the bodhi tree Ficus religiosa L. (Urticales: Moraceae). The male and the whitefly host association of Baeoentedon are recorded for the first time. A key is also provided to females of the world species of the genus.

Three new species of Coccobius Ratzeburg (Hymenoptera, Aphelinidae) and redescription of C. abdominis Huang and C. furviflagellatus Huang from China.

Three new species of Coccobius Ratzeburg (Hymenoptera: Aphelinidae) are described from China, Coccobius bimaculatus Wang, Huang & Polaszek sp. nov., Coccobius jinshanensis Wang, Huang & Polaszek sp. nov. and Coccobius leptocerus Wang, Huang & Polaszek sp. nov. Coccobius abdominis Huang 1994 and Coccobius furviflagellatus Huang 1994, originally described in Chinese, are redescribed in English and illustrated by macrophotography based on newly collected material. All five species were reared from Diaspididae (Hemiptera) scale insects on bamboo. Both the male of C. furviflagellatus and the diaspidid host association of C. abdominis and C. furviflagellatus are recorded for the first time.

[Parasitic functional response of Coccobius azumai Tachikawa (Hymenoptera: Aphelinidae) to Hemiberlesia pitysophila Takagi (Homoptera: Diaspididae)].

With female Hemiberlesia pitysophila adult as the host, this paper studied the parasitic functional response of Coccobius azumai in laboratory. The results showed that the response of C. azumai fitted Holling Type II equation, and was affected by temperature and the densities of host and parasitoid. At the same temperature, the number of parasitized host increased with increasing host density. At 15 degrees C-25 degrees C, the parasitized number increased with temperature; while at 25 degrees C-35 degrees C, it was in adverse. There was a stronger intraspecific interference in the parasitic functional response of C. azumai, i.e., the number of parasitized host decreased with increasing C. azumai density. The relationship between searching efficiency (E) of C. azumai and its density (P) could be well simulated as E = 0.1659P(-0.5597) by Hassell (1969) model E = QP(-m) and as E = 0.1437T/ [1 + 0.2691 (P -1)] by Beddington (1975) model E = aT/[1 + bt(w) (P-1)].